Growth and DNA synthesis of bacteriophage phi x174 in a dnaP mutant of Escherichia coli.

phi X174am3trD, a temperature-resistant mutant of bacteriophage phi X174am3, exhibited a reduced ability to grow in a dnaP mutant, Escherichia coli KM107, at the restrictive temperature (43 degrees C). Under conditions at which the dnaP gene function was inactivated, the amount and the rate of phi X174am3trD DNA synthesis were reduced. The efficiency of phage attachment to E. coli KM107 at 43 degrees C was the same as to the parental strain, E. coli KD4301, but phage eclipse and phage DNA penetration were inhibited in E. coli KM107 at 43 degrees C. It is suggested that the dnaP gene product, which is necessary for the initiation of host DNA replication, participates in the conversion of attached phages to eclipsed particles and in phage DNA penetration in vivo in normal infection.


Prophage substitution and prophage loss from superinfected Escherichia coli recA(P1) lysogens.

It is shown that the plasmid prophage P1 can be displaced by a superinfecting P1 phage in Escherichia coli recA(P1) lysogens. Six widely separated phage markers were used to distinguish between residual recombination and total substitution. It is further shown that superinfection of recA lysogens can lead to loss of both phage (curing). These two phenomena, previously reported in Rec+ strains, are thus independent of host recombination and may result from perturbations of some function involved in plasmid maintenance.


Host cell DNA chain initiation protein requirements for replication of bacteriophage G4 replicative-form DNA.

Bacteriophages G4ev1 and G4bs1 are simple temperature-resistant derivatives of wild-type G4 as demonstrated by restriction endonuclease analyses. The rate of replication of the duplex replicative-form DNA of these phages was normal in dnaB and dnaC mutants of the host, whereas the rate was markedly reduced in a dnaG host mutant at the restrictive temperature. We conclude that G4 duplex DNA replication requires the host cell dnaG protein, but not the dnaB and dnaC proteins. The reasons for the differences between our conclusions and those based on previously published data are documented and discussed.


Protein induced by bacteriophage T4 which is absent in Escherichia coli infected with nuclear disruption-deficient phage mutants.

A protein induced by wild-type T4 phage which is absent in Escherichia coli infected with nuclear disruption-deficient phage (with mutations in gene ndd) was identified by polacrylamide gel electrophoresis. This protein was synthesized at maximum rate at 3 to 6 min after infection. It had a molecular weight of 15,000 determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. It was associated with sedimentable fractions of the cell from which it can be dissociated with 1 M guanidine-hydrochloride. The dissociated protein can be partly recovered in a form soluble in dilute buffer after partial purification and dialysis. The occurrence of this protein in a particulate cell fraction is of interest because of the postulated role of the bacterial cell membrane in nuclear disruption.


Butorphanol and meperidine compared in patients with acute ureteral colic.

Pain relief was evaluated in 81 patients with acute ureteral colic and the confirmed presence of a calculus. A randomized double-blind comparison of intramuscular 2 and 4 mg. butorphanol and 80 mg. meperidine was used. Pain intensity and pain relief were evaluated at half hour and hourly intervals for 4 hours. A 2 mg. dose of butorphanol was found to be analgesically equivalent to 80 mg. meperidine, while a 4 mg. dose of butorphanol was found to be more effective than 80 mg. meperidine and 2 mg. butorphanol. Each patient received up to 2 doses of analgesic medication when necessary. There was no significant difference in the incidence of side effects among treatments. One patient had visual hallucinations after a 2 mg. dose of butorphanol, possibly owing to its antagonistic activity to significant narcotic experience given previously at another hospital. There was no other evidence of toxicity with butorphanol. It was found to be a safe, effective and wall tolerated drug for the treatment of ureteral colic and is recommended in place of narcotics.


A double-blind study of trimethoprim-sulfamethoxazole prophylaxis in patients having transrectal needle biopsy of the prostate.

We studied 89 men undergoing transrectal prostatic biopsies to determine the efficacy of trimethoprim-sulfamethoxazole in preventing postoperative fever, bacteremia and bacteriuria. Of the patients who received placebo temperatures of 37.6C or more occurred in 18%, bacteremia in 70% and bacteriuria in 21%. Most cases of bacteremia were caused by anaerobic organisms and were asymptomatic. Trimethoprim-sulfamethoxazole did not reduce the frequency of fever or bacteremia but did produce a significant reduction  in bacteriuria (0 versus 21%, p equals 0.008).


Antimicrobial resistant Salmonella spp. isolated from double-crested cormorants (Phalacrocorax auritus) and common loons (Gavia immer) in Florida.

Antimicrobial resistant Salmonella spp. were found in double-crested cormorants and common loons in Florida. Single or multiple resistance occurred in all Salmonella agona isolates from cormorants, primarily to ampicillin, sulfonamids, streptomycin, neomycin, and kanamycin. Similar patterns of resistance were found in S. agona isolates from common loons. In addition, isolates of S. Saint paul from loons were found resistant to tetracycline and streptomycin, while 2 of 7 isolates of S. infantis were resistant to tetracycline only.


A study of two species of fish inoculated with spruce budworm nuclear polyhedrosis virus.

Preliminary studies conducted on rainbow trout (Salmo gairdneri) and white suckers (Castostomus commersoni) exposed to spruce budworm nuclear polyhedrosis virus revealed minor histopathologic changes in various organs of each fish which were interpreted as not being significant. However, an evaluation (mean values) of the total changes in groups of fish suggested that a relationship may exist in the suckers exposed to either purified polyhedra or virions. A more extensive and definitive study must be done before any conclusions are warranted.


Serratia marcescens bacteremia from contaminated pressure transducers.

Primary Serratia marcescens bacteremia developed in 17 patients in an intensive care unit after exposure to pressure monitoring devices. A study showed that all of the transducer heads were contaminated with S marcescens, and prospective culturing of 110 pressure monitoring lines disclosed a 24% rate of contamination with the same organism. Hand contamination occurs at the time the equipment is initially assembled; in five of eight trials, transmission was shown experimentally to occur by direct inoculation of open ports. Routine disinfection of the transducer heads with glutaraldehyde not only effectively decontaminated all pressure monitoring lines in use, but also controlled the outbreak.


A mass dissection technique for determining infectivity rate of filariasis vectors.

A mass dissection method is described using an apparatus with a 55 mesh cotton sieve (244 micron pore size), which proved efficient in detecting the infectivity rate of bancroftian filariasis in Culex p. fatigans. A recovery rate of more than 98% was obtained after one hour's settling when a known number of infective larvae was released through the sieve. In the comparative tests of individual- and mass-dissection of mosquitos from the same origin, the number of infective larvae recovered in the mass dissection was almost the same as that in individual dissection. By manual centrifuging of the saline solution, it is possible to concentrate larvae at the bottom of the sedimentation tube.


Restrospective correlation of clinical and histologic findings of 189 exchanged kidneys.

Tissues samples from 189 unsuccessful renal allografts, 47 recovered at autopsy and the others removed surgically, were examined histologically by light microscopy. Tissues samples were obtained from cadaver kidneys that had been exchanged regionally for transplantation. Each allograft tissue sample was rated as to extent of pathologic changes denoting rejection and was classified accordingly. Surgical and autopsy reports, as well as clinical data, were then obtained and these were compared with the retrospective pathologic findings of this study. Our pathologic findings agreed with the original pathologic diagnosis as to presence or absence of rejection changes in 180 cases, but disagreed with the clinical diagnosis of rejection in 28 of the 63 cases with minimal or no histologic evidence of rejection. There was less disagreement with the clinical diagnosis for the 87 cases with histologic evidence of rejection which had been judged as sufficient to cause allograft loss, 70 having been clinically diagnosed as rejected. Disagreement occurred most often where the allograft had never functioned or had been lost within 3 months. Retrospective analysis did not disclose any association between rejection histology and preformed antibodies or length of kidney perfusion time. Sufficient allografts appeared to have been lost for reasons other than rejection to cast doubt on the validity of interpreting renal allograft data only by graft survival statistics.


Historical development of saralasin.

The research environment in which saralasin was discovered has been described, and illustrations of the rationale which contributed to its synthesis, selection for development, and eventual development have been presented. As an example, the synthesis of [Sar1, Val5, Ala8]-AII (P113, saralasin) was an attempt to make an AII antagonist which would be resistant to metabolism by aminopeptidases. Subsequent evaluation, however, indicated that the substitution of sarcosine had not only protected against aminopeptidase degradation but unexpectedly also had greatly increased the octapeptide's affinity for vascular smooth muscle receptors. Finally, the laboratory demonstration of saralasin as a potential therapeutic and diagnostic entity and the clinical confirmation of use of saralasin in hypertensive patients are reviewed.


[Mushroom poisoning in childhood].

The authors describe frequency and importance of poisoning by Amanita phalloides. There are demonstrated the different toxins and their biochemical properties. The typical clinical symptoms of the intoxication by Amanita phalloides with vourse in two phases (1. gastrointestinal phase, 2. hepatonephrotic phase) are shown. The possibilities of diagnostic and differentialdiagnostic and the problems of therapy are discussed. It is pointed out, that in a modern treatment there must be given Penicillin-G-Natrium in high dosage as early as possible, also in cases of questionableness. Hemodialysis is only of effect till 40 hours after ingestion of Amanita.


[Retinal detachment surgery: Incidence and causes of silicone sponge implant rejection].

In 51 patients with retinal detachments silicone sponge implants have been applicated. In 9 of these cases (17,6%) the implants had to be removed 3 weeks to 16 months postoperatively because of inflammatory reactions. The influence of these complications on the healing of the retinal detachment is considered as relatively unimportant. In light- and electron-microscopic examinations we could establish that the reactions are mainly caused by infections (which primarily spread within the caves of the sponge implants). Chronic infections caused by so-called apathogenic bacteria are more frequent than acute infections by so-called pathogenic micro-organisms. A foreign body reaction could be proved only in one case, in which the sponge was loosened and displaced. Defence reactions against the foreign body material probably develop only if mechanical irritation of the tissue is caused by the sponge material.


[Reduced production of aqueous humor in Fuch's corneal dystrophy].

Fuchs' corneal dystrophy is associated with a reduced production of the aqueous humor, as can be established via tonography. The trophopathy and cornea guttata caused thereby are prerequisites for the production of Fuchs' corneal dystrophy. The aqueous humor production should be examined before keratoplasty, since the prognosis is questionable if the production is low. If no improvement of visual acuity can be excepted, keratoplasty should not be performed, since pain has also been relieved by means of intracorneal acrylate implantates.


[Artificial lens implantations of Medallion - lenses (author's transl)].

Description of the surgical technique of artificial lens implantations extra- and intracapsularly. Only the original Medallion -lens for flexible suture fixation and the "slotted" Medallion - lens for steel suture fixation will be described with brief mention of Platina clip lens for extra-capsular surgery, the Small incision lens, the Three loop lens and the Boomerang lens.


Identification of a low moleculr weight IgM antibody with treponema pallidum specificity in sera of patients with chronic syphilis.

A low-molecular (8S) treponema-specific IgM antibody was isolated by means of Sephadex 200 G gel filtration and/or sucrose gradient ultracentrifugation in 78 of 4,120 sera of patients who had been identified to have had syphilis. The IgM specificity can be shown by indirect immunofluorescence using a mu-chain specific antiserum. The low molecular IgM (LMW-IgM) antibodies are not identical with the 19S-IgM as demonstrated in studies with gel filtration and sucrose gradient methods. They are not identical neither with 7S IgG or IgA. Neither the presence of antinuclear nor rheumatic factor could be shown in the LMW-IgM fraction. In most of the patients with LMW-IgM antibody, there existed a treponema infection of late latency.


[On the history of intraocular lenses (author's transl)].

A short review on the world-wide and Swiss history of the three generations of intraocular lenses is recorded: the implantation of posterior and anterior chamber lenses is completely given up in Switzerland. Prepupillary 2- and 4-loop-lenses of the Binkhorst type are used at the Lucerne Eye Hospital since 1973. A major brakethrough of artificial lens'implantation in Switzerland is expected in 1979.


Studies on Tyzzer's disease: acquired immunity against infection and activation of infection by immunosuppressive treatment.

The correlation between serum antibody titre and resistance to challenge infection with Bacillus piliformis was studied in naturally infected mice, in experimentally infected but recovered mice, and in mice treated with antigen prepared from infected livers. Irrespective of the way in which the antibodies were acquired resistance to infection was found to be related to the immunofluorescence antibody titre found. Experimentally infected but recovered mice, as well as rats with persistent antibodies to Bacillus piliformis, were given prednisolone in order to activate a possible persistent infection. Bacillus piliformis was detected in the rats, but not in the mice.


Is encephalitozoonosis a zoonosis?

Encephalitozoon cuniculi has often been cited as a human pathogen although few cases (of disease) have been described in the literature. A discussion of these cases suggests that this microsporidium should not be regarded as a pathogen of man.


Surgical technique to reduce the risks of heart block following closure of ventricular septal defect in atrioventricular discordance.

Traumatic heart block remains a major concern after ventricular septal defect (VSD) closure in patients with atrioventricular discordance. A technique of closing the VSD, placing the suture line on the morphologically right side of the septum without opening the systemic ventricle, is described. This was used in 13 consecutive patients. The VSD was closed through the right atrium in eight patients, the left ventricle in three patients, the right atrium and the left ventricle in one patient, and through the right ventricle in one patient with atrioventricular disordance and ventriculo-arterial concordance. All patients were in sinus rhythm preoperatively, two exhibited atrioventricular dissociation before intracardiac manipulation began, and 11 patients were in sinus rhythm postoperatively. No major arrhythmia could be attributed to the closure of the VSD.


Guidelines for safely opening a previous sternotomy incision.

Operations through a previous sternotomy incision are associated with significant hazards, including cardiac injury, excessive hemorrhage during and after cardiopulmonary bypass, and postoperative sternal instability. A technique for safely opening previous sternotomy incisions has been developed at New York University Medical Center which has proved satisfactory in over 150 patients. It has been demonstrated repeatedly to be free of the serious and often lethal intraoperative and postoperative complications previously associated with this procedure.


Restoration of impaired immune functions in aging animals. II. Effect of mercaptoethanol in enhancing the reduced primary antibody responsiveness in vitro.

The enhancing effect of 2-ME on the in vitro primary antibody forming capacity of young and old spleen cells from 5 different strains and hybrids was investigated by assessing the number of antibody-forming cells in response to sheep RBC stimulation. The following results were obtained: (1) the optimum concentration of 2-ME is 5 x 10(-5) M; (2) the best time to expose cultures to 2-ME is on day 0 together with the antigen, although days 3 and 4 were equally as effective with young but not old spleen cells; (3) 2-ME can enhance slightly the time of peak antibody response, but this appears to be strain dependent; (4) in response to antigenic stimulation over a 10,000-fold range in antidgen dose, antibody response by cultures exposed to it; (5) 2-ME is comparable to, or better than, those which had been exposed to it; (5) 2-ME is effective in enhancing antibody response because it probably promotes proliferation and transformation, as well as protects dividing cells which otherwise could not survive the culture conditions; (6) the relative number of viable cells detected on the third day of culture after antigen stimulation can be used in predicting with a reasonable accuracy (pie 2, 0.94) the magnitude of peak antibody response, which is detected normally about 2 days later; (7) 2-ME enhances antibody response of young spleen cells by about 30%, but is quite variable depending upon the genetic strain, varying from a low of --20% with random bred CV1 cells to a high of 100% with inbred C57B1 cells; (8) the enhancing effect of 2-ME on old spleen cells is much more impressive, being more that 10 times greater than on young spleen cells (i.e., 500 vs. 30%), although it too is quite variable, ranging from a low of 85% with C3H cells to a high of about 1100% with C57BL cells; (9) the enhancing effect of 2-ME on limiting numbers of spleen cells is most impressive, as judged by the relative magnitude of response by limiting (3 x 10(6)) and optimum numbers (10 x 10(6)) of young and old spleen cells and by the frequency of antibody response of cultures with limiting and optimum numbers of cells exposed to 2-ME was 23 and 3 times greater than that not exposed to 2-ME, respectively; and with old spleen cells, it was 30 and 12 times greater. In terms of the frequency of antibody responding cultures with limiting numbers of young spleen cells (3 x 10(6)), 77% responded in absence of 2-ME, whereas 100% of the cultures responded in the presence of 2-ME. The effect of 2-ME on cultures containing limiting numbers of old spleen cells was much more striking, for, in contrast to only 9% of the cultures responding in the absence of 2-ME, 78% responded in the presence of 2-ME.


Age-associated changes in T-B cell cooperation demonstrated by the allogeneic effect.

The allogeneic effect results in an increase in the number of antibody-producing cells (PFC) when the allogeneically stimulated lymphoid cells and the antibody-producing cells are from young individuals. This increase depends on the interaction of allogeneically stimulated T-cells and precursor plasma cells (B-cells). Age-associated deficiencies in these two cell populations were studied in these experiments by use of allogeneically stimulated T-cells from old donors or responding B-cells from old recipients. These experiments showed that lymphocytes from 20-month-old mice were capable of inducing an increase in PFC in young recipients. However, the allogeneic effect was ineffectual in 12-month-old mice. These data suggest that the T-helper function is equally capable in mice 4 to 20 months old, but that the B-cell is not as effectively recruited. The possible causes for limited B-cell recruitment are discussed.


An index of accessibility for ambulatory health services.

This paper discusses an Index developed and used to measure accessibility to health services provided on an outpatient basis at the Kaiser Community Health Foundation, Cleveland, Ohio. The Index is based on four levels of urgency or severity of illness and on the waiting times to get entry into the system. The parameters of the Index, initially established by task force members, were tested on a sample basis against the judgments of Kaiser outpatient facility users and finally refined through the consensus-seeking Delphi technique using a panel representing Kaiser members, gatekeepers, physicians and administrators. The actual times required to gain accessibility in the various process stages and in the various departments were obtained through simulated requests for appointments, by monitoring telephone calls to the various gate-keeping stations, by direct observations, and by the use of a telephone traffic computer. The paper discusses the Index developed, the data collection methodologies, and the data analyses performed.


[Zollinger-Ellison syndrome type II due to diffuse hyperplasia of the pancreatic islet cells (author's transl)].

A 58-year-old patient with hypergastrinemia (basal and after stimulation by means of protein food, calcium, glucagon, and secretin), acid hypersecretion, recurrent anastomotic ulcer, gastrocolonic fistula, steatorrhea, and malabsortion (hypocalcemia, hypocholesterolemia and a rather elevated 5-HIAA) is reported. The definite preoperative diagnosis of Zollinger-Ellison syndrome was established after the intravenous secretin test (75 U) which produced a significant stimulation peak 5 minutes after being injected. The possible existence of a multiple endocrine adenomatosis syndrome type I was discarded. During the operation no pancreatic or extrapancreatic macroscopic tumor was found. A total gastrectomy, transverse colectomy, splenectomy, and subtotal pancreatic resection were performed; Rosanow's techniques was used to re-established the gastrointestinal continuity. The morphological study of the excised pancreatic tissue showed a diffuse hyperplasia of the Langerhans islet cells; indirect immunofluorescence in the presence of antigastrin antibodies was faintly positive and difficult to evaluate. However, gastrin levels clearly decrease after the operation may be because the inhibitory effect of total gastrectomy or because of the partial pancreatectomy. Furthermore, the inhibitory effect of tyrocalcitonine onthe pre- and postoperative gastrin levels measured by radioimmunoassay could be verified. For the moment the importance of this test in the diagnosis of Zollinger-Ellison syndrome, and especially in the diagnosis of ZES-type II, is not known.


[Legionnaires' disease (author's transl)].

Since Legionnaires' disease was diagnosed in Spain for the first time, we have considered it of interest to review the subject and to bring it up to date as much as possible. Legionnaires' disease is an infectious illness which principally affects people in the fifth decade of life and which has been diagnosed in different countries in the world, including Spain. The etiologic agent is a Gram-negative bacteria, which does not grow in the normal culture media and which requires special stains for its identification. Clinically the disease presents as an atypical pneumonia accompanied by gastrointestinal symptoms and hyponatremia as a characteristic laboratory finding. It appears with greater frequency during the summer season in an epidemic form, although isolated cases have been reported during the entire year. It is potentially a very severe condition, and the mortality rate has been calculated at 15--20 percent. A definite diagnosis requires the isolation of the etiologic agent: directly, by stain (direct immunofluorescence, Dieterle's silver stain), isolation and culture in an enriched media (Mueller-Hinton agar supplemented with Iso-Vitalex and hemoglobin), or indirectly by serologic methods (indirect immunofluorescence). Eryhtromycin is the antibiotic of choice with or without the association of another antibiotic of wider spectrum.


[Adquired epidermolysis bullosa. Immunopathological and ultrastructural studies].

A case of epidermolysis bullosa acquisita (EBA) in a 64 year old man is reported. The direct immunofluorescence showed a positive lineal anti IgG basement membrane on the affected skin (blisters and provocation tests) and on the univolved healthy skin. The electron microscopic studies showed a "dermolysis". In this patient it was not possible to find any pathological association. The EBA is usually associated with different processus but, sometimes, it could be isolated. Probably this clinicopathological field includes diverse badly delimited entities.


[Metabolic studies in brothers affected by alcaptonuria (ochronosis)].

The case of two brothers affected by alcaptonurie is reported. The activity of the homogenthisycasa enzyme has been determined by the material obtained through percutaneous biopsy. Concentrations of the aminoacids producing fenilalanina and thiroxina in their parents' blood have been investigated, the tests showing lack of liver enzyme and normal concentration of the amount of aminoacids in blood. Some aspects of skin lesion have been briefly reported and methods for treatment presented.


[Non hereditary porokeratosis of Mibelli].

After a short review of the literature on the clinical and histopathological features of PM, 66 cases of the disease observed in the past 14 years at the IPO Dermatology Deparment are presented. They are compared with the previously mentioned case reports, particularly the ones published in the portuguese literature. The existance of two forms of the disease is suggested, and the differences between them specified. Treatment is considered, with special emphasis on the cases with a small number of lesions.


[Jorge Lobo disease. Study of 2 cases with disseminated lesions and plantar invasion].

The Author describes two cases of Jorge Lobo's disease, with disseminated lesions and plantar invasion, originating from Cruzeiro do Sul, state of Acre and Manaus, state of Amazonas. In both cases, the disease was of long duration, 30 and 55 years respectively. In the second patient described the disease began 9 years before Jorge Lobo described this condition. In spite of the duration of the illness in this patient 76 years of age, he was in good physical condition without any apparent suggesting dissemination of the mycosis.


[Netherton-Comel's syndrome].

Two cases of the so-called Netherton's syndrome are described and the relevant literature is reviewed. On the author's opinion there exists no relationship between the disease and ichthyosiform dermatoses. It fits more adequately in the group of the "Génodermatoses érythémato-desquamatives circinées variables" of Bazex and Dupré. The syndrome is characterized by the association of two tipical clinical features: "Trichorrhexis invaginata", reported by Netherton and the "Ichthyosis linearis circumflexa", described by Comel. The authors propose therefore the eponymous designation of "Syndrome of Netherton-Comel". As there exists no link with the group of the ichthyosiform dermatoses, the authors suggest the name of "Dyskeratosis figurata variabilis" for the disease described described by Comel.


[Erythema elevatum diutinum].

Three cases of Erythema Elevatum Diutinum are reported and a revision of the literature about this subject is made. The authors described extensively the general and cutaneous clinical picture. They precise the histological characteristics and mention other dermatological proceses from which this entity must be differentiated. Finally the ethiology and treatment of this clinical picture are discussed.


[Anatomical function of the small intestine (malabsorption syndrome) in dermatological diseases].

Fifty patients with various long lasting skin diseases were examined. Past history and digestive-nutritional symptoms were recorded. Two or three samples of distal duodenum, elimination of fecal fat and d-xylose absortion test were intended to be performed in all patients, but this coincident parameters were obtained in only 35 patients. Twenty two of these patients were classified as abnormal by 1 of the 3 investigations (62,85%), and 9 (25,71%) were abnormal by 2 criteria. In addition to these usual studies, vit B12 and folic acid absortion were tested in 12 and 23 cases respectively. Distribution does not allow for comparison of the "sensibility" of such tests with the forementioned ones. While only 2 of the 12 patients showed defective absorption of B12, 8 of 22 cases presented with defect of absorption of folic acid. Of this last group, 5 were cases of eritrodermia (the test was performed in 6 cases with this diagnosis). In the total series of 50 cases, including those not thoroughly studied, 27 (54%) presented at least with one abnormal study. These observations point to the possible frequency of intestinal absorption alterations, in several skin diseases, though of moderate degree and pertaining to variable absorption functions. They validate the prosecution of the study, with the aim of clarifying the etio-pathogenesis of some dermatological entities and trying to contribute to their therapy.


Effects of physical training and cardiorespiratory physical fitness on exercise-heat tolerance: recent observations.

Most authors agree that physical training in a cool environment improves tolerance to exercise in the heat and the rate of heat acclimatization, but the extent or degree of improvement remains controversial. The best improvement in heat tolerance for men is associated with intensive interval or continuous training at a training intensity greater than 50% of maximal oxygen uptake (Vo2max) for 8-12 weeks; the Vo2max should be increased 15-20%. Far less is known about the appropriate type, intensity and duration of endurance training associated with improved exercise-heat tolerance in women. The major benefits of physical training appear to apply to both short term (less than 2 hrs) or long term (greater than 2 hrs) exercise-heat exposures for men. Generally, individuals with high Vo2max values (previously trained and endurance athletes) are at an advantage in the heat. Utilization of proper physical training appears to produce about 50% of the total adjustment resulting from heat acclimatization, while increased fitness is associated with greater retention of acclimatization in cool environments. Female athletes appear somewhat better able to tolerate exercise in hot environments than nonathletic females while differences between highly trained females and males do not appear as dramatic as once thought.


Effects of exercise in the heat on predisposition to heatstroke.

This article reviews briefly the historical origins for both the cardiovascular and neural-anhidrotic concepts of heatstroke pathophysiology. It describes how deemphasis of the role of anhidrosis as the primary cause of heatstroke has resulted in: (a) an increased acceptance of animal models for heatstroke research; (b) further evidence that rigid reliance on the classic heatstroke symptoms (coma, anhidrosis, and a fever over 106 degrees F) can result in underdiagnosis; and (c) new research consistant with the hypothesis that exhaustive physical effort, by worsening circulatory collapse and metabolic acidosis predisposes tissue to hyperthermic injury and, as a result, substantially lowers the threshold for heatstroke injury and mortality. Thus, a new hypothesis combining the essential features of both direct thermal injury and cardiovascular origins of heatstroke pathophysiology may be necessary.


[Immunothermistor unit].

An immunotermistor has been devised for studying immunological reactions. It includes a probe pack, a measuring pack and an automatic potentiometer. The adoption of analogue integral microcircuits enabled the authors to make a unit with high reliability, small size and mass. The error in assessing immunological reaction parameters does not exceed 5%.


Antiglomerular basement membrane antibody-mediated glomerulonephritis and Goodpasture's syndrome.

The originally dismal prognosis associated with anti-GBM Ab-mediated GN and Goodpasture's syndrome may be changing as we recognize a broader spectrum of disease, improve general supportive care, and improve specific treatment. Immunosuppressive therapy, if started early in the course of disease, may prevent or allow recovery from renal failure and may also result in cessation of recurrent pulmonary hemorrhage in most patients with this form of Goodpasture's syndrome. The administration of pharmacologic doses of corticosteroids intravenously can result in cessation of and dramatic recovery from severe pulmonary hemorrhage and obviate the need for emergency bilateral nephrectomy. Plasmaspheresis may represent a useful therapeutic procedure for the immediate and long term reduction in amounts of circulating anti-GBM Ab, but the definition of its true value and role awaits completion of controlled, prospective trials. Immunosuppressive therapy, with or without plasmapheresis, can reduce quantities of anti-GBM Ab in serum to undetectable levels without nephrectomy. Thus, it is likely, but not proven, that nephrectomy can be discontinued as a routine pretransplantation procedure in patients with anti-GBM Ab mediated GN. Finally, in patients who suffer irreversible renal failure, renal transplantation can be successfully undertaken with minimal risk of recurrent disease, when circulating anti-GBM Ab becomes undetectable.


[Cardiac rhythm analyzer based on the 15 VSM-5 program-controlled calculator].

Automatic analysis of the cardiac rhythm recorded through electrodes connected in various lead patterns can be carried out with a measuring and calculating complex, based on a program controlled calculator provided with the program for the rhythm analysis. The functional basis of this complex is a block controlling the information input, and it is described comprehensively.


Identification of the C. coli dnaK (groPC756) gene product.

The E. coli dnaK (groPC756) gene product is essential for bacteriophage lambda DNA replication. Bacterial DNA segments carrying this gene have been cloned onto a bacteriophage lambda vector. The product of the dnaK gene has been identified on SDS polyacrylamide gels after infection of UV-irradiated E. coli cells. The dnaK gene codes for a polypeptide with an apparent molecular weight of 93,000-Mr. Transducing phages carrying amber mutations in the dnaK gene fail to induce the synthesis of the 93,000-Mr polypeptide chain upon infection of sup+ bacteria, but do so upon infection of supF bacteria. E coli carrying the dnaK756 mutation are, in addition, temperature sensitive for growth at 43 degrees C. It is shown that the dnaK756 mutation results in an overproduction of the dnaK gene product at that temperature.


[Automatic 2-wave length cytophotometer with a calculator].

The described microscope photometer is intended for determination of biologically active substances in stained cells. It consists of a photometric attachment to a standard microscope, a measuring device and a block for digital data processing with a calculator 15 BCM-5 or a microcalculator (Formula: see text). The model with the microcalculator is described in detail.


Nucleotide sequence of small ColE1 derivatives: structure of the regions essential for autonomous replication and colicin E1 immunity.

A small ColE1 derivative, pAO2, which replicates like the original ColE1 and confers immunity to colicin E1 on its host cell has been constructed from a quarter region of ColE1 DNA (Oka, 1978). The entire nucleotide sequence of pAO2 (1,613 base pairs) was determined based on its fine cleavage map. The sequence of a similar plasmid, pAO3, carrying additional 70 base pairs was also deduced. The sequence in the region covering the replication initiation site on these plasmids was consistent with those reported for ColE1 by Tomizawa et al. (1977) and by Bastia (1977). DNA sequences indispensable for autonomous replication were examined by constructing plasmids from various restriction fragments of pAO2 DNA. As a result, a region of 436 base pairs was found to contain sufficient information to permit replication. The occurrence of initiation and termination codons and of the ribosome-binding sequence on pAO2 DNA suggests that a polypeptide chain consisting of 113 amino acid residues may be encoded by the region in which the colicin E1 immunity gene has been mapped.


Isolation and restriction mapping of plasmids containing ribosomal DNA sequences from the rrn B cistron of E. coli.

Recombinant plasmids containing the entire 16S RNA gene from the rrn B cistron of E. coli inserted in Col E1 and pBR322 plasmid vectors have been constructed. These plasmids have been mapped using several restriction endonucleases as well as by DNA-RNA hybridization. These maps reveal previously undetected restriction sites in the rrn B cistron and in Col E1 plasmid DNA.


Thymidine sensitivity of certain strains of Escherichia coli K12.

In studies on thymineless death in Escherichia coli K12, it was noted that certain thymine requiring mutants were inhibited by thymidine. The pattern of inhibition varied with the conditions and media employed. Accumulation of deoxyribose-5-phosphate as a possible reason for inhibition is ruled out since the strains are deoB- (formerly drm-) and synthesize deoxyriboaldolase constitutively. We report this inhibition to alert investigators who study thymidine metabolism or use thymidine to label the DNA.


Regulation of mitochondrial ribosomal RNA synthesis in yeast. I. In search of a relaxation of stringency.

Studies were undertaken to determine if mitochondrial rRNA synthesis in yeast is regulated by general cellular stringent control mechanism. Those variables affecting the relaxation of a cycloheximide-induced stringent response as a result of medium-shift-down or tyrosine limitation include: 1) the stage of cell growth, 2) carbon source, 3) strain differences and, 4) integrity of the cell wall. The extent of phenotypic relaxation decreased or was eliminated entirely in a strain dependent manner as cells entered stationary phase of growth or by growth of cells on galactose or in osmotically stabilized spheroplast cultures. Cytoplasmic and mitochondrial RNA species were extracted from regrowing spheroplast cultures subjected to different experimental regimens and analyzed by electrophoresis on 2.5% polyacrylamide gels. Relative rates of synthesis were determined in pulse experiments and normalized by double-label procedures to longterm label material. Tyrosine starvation was found to inhibit synthesis of the large and small rRNA species of both cytoplasmic and mitochondrial rRNAs to about 5-20% of the control values. Chloramphenicol inhibits mitochondrial and cytoplasmic rRNA synthesis to 60-80% of control; however, chloramphenicol addition does not relax the stringent inhibition of either class of rRNAs. Cycloheximide addition results in 70-80% inhibition of synthesis of both cellular speceis of rRNAs. As noted above, cycloheximide does not relax the stringent response of cytoplasmic rRNA synthesis in spheroplasts, and also does not relax the stringent inhibition of mitochondrial rRNA synthesis. From these studies, we conclude that both cytoplasmic and mitochondrial rRNA synthesis share common control mechanisms related to regulation of protein synthesis by shift-down or amino acid limitation.


Multiple fusion of protoplasts in Saccharomyces yeasts.

Fusion of protoplasts prepared from haploid strains of Saccharomyces yeasts having identical mating type was induced with the aid of polyethylene glycol. Stable fusion products were isolated by complementation of the auxotrophic markers. Of 64 isolates derived by protoplast fusion between two different haploid strains having alpha mating type, 35 fusion products were estimated from their cell volumes to be diploid, 13 to be triploid and 16 to be tetraploid. The isolates showing tetraploid cell size were thought to have resulted from fusion of three protoplasts of one strain and one protoplast of the other (three-to-one fusion) or from two-to-two fusion. In protoplast fusion of three different haploid strains having alpha mating type, all four possible phenotypes of fusion product were recovered. Fusion products of three different protoplasts were obtained in much lower frequency (2.1 x 10(-6)) than those of two different protoplasts (1.2 x 10(-5) to 1.4 x 10(-4)) in the three other combinations. Genetic analyses revealed that triploid fusion products were formed by protoplast fusion of two different strains as well as of three different strains.


Use of RP4-prime plasmids constructed in vitro to promote a polarized transfer of the chromosome in Escherichia coli and Rhizobium meliloti.

RP4-prime plasmids containing chromosomal fragments of either Escherichia coli or Rhizobium meliloti were constructed in vitro. When introduced into E. coli or R. meliloti respectively, they promoted a polarized transfer of the chromosome as demonstrated either by the gradient of transfer of various markers or by the study of the genetic constitution of recombinants. In E. coli, mobilization was shown to be dependent upon the presence of a functional rec A system. Inheritance of markers was due to their integration into the chromosome of the recipient as shown by the need for a functional rec A system in the recipient E. coli or by mobilization of recessive markers in R. meliloti. The system described could be applied to genetic mapping in any Gram negative bacteria.


Mitochondrial activity of 2,6-diaminopurine in Saccharomyces cerevisiae.

2,6-diaminpurine (DAP) selectively inhibited mitochondrial protein synthesis in yeast cells with concomitant failure of cells to grow in non-fermentable (yeast extract, glycerol) medium. The selectivity was pronounced in all strains tested (15) nearly all of which were able to grow in yeast extract, glucose medium containing 5 mg/ml DAP (maximum solubility) whereas growth was arrested in all strains at 250-500 microgram/ml DAP in the glycerol medium. The inhibition was reversed by further addition of adenine to the culture medium. RNA synthesis in rat liver mitochondria was depressed by DAP suggesting that the analogue affected RNA polymerase activity. There was no evidence of nuclear mutagenicity by DAP but resistance to the antibiotics chloramphenicol and oligomycin was induced by the drug. Genetic evidence, although limited, indicated that the resistance mutations were cytoplasmic. The mitochondrial petite mutation was also induced by DAP but only at comparatively high concentrations. The mutagenic effects were seen only in the glycerol medium.


Regulation of the L-arabinose operon in strains of Escherichia coli containing ColE1-ara hybrid plasmids.

Hybrid plasmids were constructed from fragments of F'ara episomes formed by the restriction endonuclease EcoRI and a linear form of the plasmid ColE1 created by cleavage with EcoRI. Hybrid plasmids were constructed containing the entire ara region or the ara region with various parts deleted. E. coli K12 host strains were constructed which contained different deletions of the ara region. The hybrid plasmids were transferred to those strains whose ara deletion complemented that of the plasmid. The initial differential rates of synthesis of L-arabinose isomerase, the product of the araA gene, were determined for the Ara+, plasmid containing strains. These studies demonstrated that strains containing delta(araOIBA)718 produce elevated levels of araC protein, suggesting the araC promoter has been altered by this deletion. Evidence is also presented which suggests that araC protein activates the ara-BAD operon to higher levels when it is present in cis rather than trans. Amplification of the products of the cloned genes is observed when compared to haploid levels in some cases.


Studies of colicin induction with an imm- col+ mutant of the plasmid colicin E1.

A mutant of a derivative of the colicin E1 plasmid has been isolated that does not confer immunity to colicin E1 on its host (imm-) although it is still capable of producing colicin (col+). Cells carrying the col+, imm- plasmid are capable of forming colonies and grow best in liquid culture in the presence of trypsin. The induction of colicin synthesis by ultraviolet light has been analysed using this mutant plasmid. The results suggest that a) the expression of the col+ gene may be delayed for many generations after the inducing stimulus, b) although induced cells are usually killed they can reproduce and c) the capacity to produce colicin can be propagated and segregated into the progeny of an induced cell.


Decreased transfer of pyrimidine dimers from parental to daughter DNA strands in UV-irradiated Escherichia coli deficient in DNA polymerase III.

The number of pyrimidine dimers (sites sensitive to UV-endonuclease from M. luteus) transferred at 43 degrees to daughter DNA strands during postreplication repair in UV-irradiated E. coli uvr A polCts was found to be decreased as compared to that after repair at 32 degrees. This indicates the involvement of DNA polymerase III in the sister DNA recombination in UV-irradiated E. coli.


Posttranslational regulation of repressible acid phosphatase in yeast.

On the basis of genetic data it has been suggested that repressible acid phosphatase of Saccharomyces cerevisiae is regulated by a control circuit involving operator-repressor mechanisms (Toh-e et al., 1978). We measured no significant difference in the amount of translatable mRNA of repressed and derepressed cells in the reticulocyte in vitro translation system. We find a 25 fold difference in specific enzyme activity in repressed versus derepressed cells whereas the amount of 35S-methionine labelled enzyme protein as measured by antibody precipitation varies only 2-3 fold. This argues for posttranslational regulation of preexisting inactive acid phosphatase. Minor regulatory effects at the transcriptional or translational level cannot be excluded.


Product induction of purine hydroxylase II in Asperigillus nidulans.

By the use of a mutation, hxB-20, that eliminates purine hydroxylase II activity but retains cross-reacting material and an ancillary NADH dehydrogenase activity, it has been established that 6-hydroxynicotinic acid rather than nicotinic acid, is the true inducer of purine hydroxylase II.


Genetic analysis of a mutation affecting ribosomal protein S1 in Escherichia coli.

Ribosomal protein S1 from a newly isolated Escherichia coli mutant has a molecular weight of about 54,000 which is smaller than the wild type S1 (M.W. 65,000). The isoelectric points of the smaller and the wild type S1 species are similar in the gel electrophoresis system of O'Farrell (1975). Genetic analyses by Hfr conjugation and P1 phage transduction indicate that the mutation affecting S1 (rpsA) is located close to the serC gene [20 min on the E. coli genetic map of Bachmann et al. (1976)], with a co-transduction frequency of 61%. The most probable gene order is serC-rpsA-cmlB.


Characterization of 10S RNA: a new stable rna molecule from Escherichia coli.

When cells of Escherichia coli are labeled with 32Pi for long periods of time and the cell content is subjected to electrophoresis in polyacrylamide gels, an RNA band appears which is about 10S in size. This band seems to contain three conformers. After treatment with formamide only a single band appears in this region of the gel, which contains 550 nucleotides as determined from its mobility. The complexity of the fingerprint of this material, after digestion with T1-RNase, is in agreement with the size as determined by the mobility, this confirming that indeed it is a single molecule. Composition of the T1-oligonucleotides was determined by digesting the T1-generated oligonucleotides with pancreatic RNase and T2-RNase. The quantitative and qualitative analysis of these digestions suggest that 10S RNA contains 609 nucleotides. The molecule contains, besides the four regular bases, one copy per molecule of the modified base pseudouridine. 10S RNA cannot be processed by cell extracts to tRNA-sized molecules and does not bind significantly to ribosomes, hence it is unlikely to be a tRNA precursor or an mRNA.


Toxic and mutagenic effects of carcinogens on the mitochondria of Saccharomyces cerevisiae.

Nineteen haploid yeast (Saccharomyces cerevisiae) strains were used to assess the relative growth inhibitory potencies on fermentable vs. non-fermentable media of a collection of carcinogenic and non-carcinogenic chemicals. The majority of carcinogens were distinctly more potent on the non-fermentable (glycerol) medium, where mitochrondrial function is required for growth, than on the fermentable medium, where it is not. The anti-mitochondrial selectivity indicated by these growth tests was much slighter for the non-carcinogens. Similarly most carcinogens induced the cytoplasmic petite mutation whereas the non-carcinogens did not. Five carcinogens which were tested impaired the development of cytochromes aa3 and b in glucose cultures. Six carcinogens, when tested, inhibited growth on three fermentable sugars, the utilisation of which requires mitochondrial function. Out of five carcinogens which were examined, four suppressed the surface-dependent phenomenon of fluocculence in a flocculating strain of yeast, at concentrations primarily affecting the mitochondrial system; the fifth had a similar but less pronounced effect.


Assembly of ribosomal subunits affected in a ribosomal mutant of E. coli having an altered L22 protein.

In this article we describe some in vivo properties of a coldsensitive ribosomal mutant from Escherichia coli. The mutation affects the rplV gene which is the structural gene of ribosomal protein L22. Our work shows that at 22 degrees C, the biosynthesis of both ribosomal subunits and the maturation processing of 15S and 23S ribosomal RNA are impaired. Integration of our results in a general model of in vivo ribosomal assembly in E. coli is presented.


Overlapping sequences of Klebsiella pneumoniae nifDNA cloned and characterized.

A HindIII (17.0 kb) and an EcoR1 restriction fragment (6.9 kb) of Klebsiella pneumoniae nif DNA were cloned on two small amplifiable plasmids, pCM1 and pSA30 respectively. These plasmids between them carry 14 of the 15 known Klebsiella nif genes. The operon for the three structural genes for nitrogenase, nifpHDK, is carried on pSA30: four and five of the remaining six operons are on pCRA37 and pCM1 respectively. All of the nif genes were assigned to endonuclease restriction fragments of DNA using the Southern blotting technique (Southern, 1975) with total DNA of nif insertion mutants and radioactive plasmid DNA which contained cloned nif DNA sequences. Their locations were consistent with the genetic map of nif genes. The estimated size of the nif gene cluster was 24 kb.


Tandem and inverted repeats of arginine genes in Escherichia coli: structural and evolutionary considerations.

Duplications of arg genes produced in the Rec+ and in the recA genetic backgrounds are shown by heteroduplex analysis to be strictly tandem at the level of resolution of this technique. The formation of these particular rearrangements therefore does not require the inclusion of transposons or other sequences of an appreciable size in their final structure. Duplications of short segments (about 2,000 nucleotides) appear unexpectedly stable when compared with duplications of longer segments (about 10,000 nucleotides). One of the structures analyzed displays two inversely repeated argE genes rearranged into an artificial divergent operon. The bearing of this observation on the origin of bipolar operons, of "mirror-image" map symmetries and on the production of inverted repeats in general, is discussed.


Do the tightly linked structural genes for nitrate and nitrite reductases in Aspergillus nidulans form an operon? Evidence from an insertional translocation which separates them.

Previous work (Rand and Arst, 1977) led to the proposal that the nis-5 mutation results in a new low activity promoter for niiA, the structural gene for nitrite reductase in Aspergillus nidulans. Expression of niiA via this promoter differs from expression of niiA via its normal promoter/initiator in that expression by the new promoter is not subject to nitrate induction or ammonium repression. nis-5 reduces but does not abolish niiA expression mediated by the normal promoter/initiator. In this work we show that nis-5 is associated with and is probably identical to a non-reciprocal translocation in which a considerable portion of the centromere proximal region of the right arm of linkage group II is inserted into linkage group VIII between niiA and niaD, the tightly linked, probably contiguous structural genes for nitrate reductase. This implies that niiA, along with its normal promots yet unidentified by its normal role. Further, it indicates that niiA is transcribed from the niaD-proximal side. As niiA and niaD are separated by a large number of unrelated genes in nis-5 strains, we can safely conclude that expression of niiA does not occur solely by synthesis of a messenger which carries a niaD as well as a niiA transcript. Clearly, niiA and niaD do not form an operon for which a di- (or poly-) cistronic messenger by the only transcript. This is consistent with other experimental evidence which shows that the syntheses of nitrate and nitrite reductases are not coordinately regulated. Nevertheless, all of these data would also be consistent with a model in which niiA and niaD form an operon-type structure having overlapping transcripts, one being di- (or poly-) cistronic and including both niiA and niaD and another being monocistronic for niiA. The reduced niiA expression mediated by the normal promoter/initiator in nis-5 strains could be a consequence of the functioning or positioning of the new linkage group II niiA promoter. An alternative, but not mutually exclusive, explanation would be that the insertional translocation prevents synthesis of a niiA niaD dicistronic transcript so that only that component of niiA expression which is due to a monocistronic niiA messenger can be induced by nitrate (and nitrite) in nis-5 strains. The apparently low activity of the new linkage group II promoter in comparison to the normal niiA promoter/initiator might betoken considerable efficiency of the latter rather than any particular lack of efficiency of the former. In addition, this work has involved extensive new mapping in linkage group II, including both mitotic mapping of the centromere and meiotic mapping of previously unlocated markers. A series of crosses in cluding genotype combinations both heterozygous and homozygous for nis-5 has been used to map the break-points and orientation of the translocation. As one break-point is closer to the centromere of linkage group II than the most centromere proximal identified gene on the same (i.e...


Structure of the malB region in Escherichia coli K12. I. Genetic map of the malK-lamB operon.

A series of deletions, Mu insertions and point mutations affecting the malK-lamB operon have been isolated. They were used to establish a deletion map of this operon, which could be divided in 27 intervals, with 16 in malK and 11 in lamB. One interesting feature of this map is the lack of randomness in the distribution of Mu insertions in the lamB gene; by using data published elsewhere on the physical length of the deletion intervals it can be concluded that about 25% of these Mu insertions are clustered in a segment representing 2 to 8% of the gene. This map is presently being used to study the biosynthesis, structure, and function of the lamB product, which is an outer membrane protein involved in the transport of maltose and maltodextrin, and which in addition constitutes the receptor for phage lambda.


Structure of the malB region in Escherichia coli K12. III. Correlation of the genetic map with the restriction map.

A correlation between the genetic and physical maps of the malB region was obtained by performing a restriction cleavage analysis of DNA's carrying various genetically characterized malB deletions. This also allowed to localize the boundaries between malF and malE, malE and malK, mal K and lamB on the restriction map. The genetic map is not grossly distorted with respect to the physical map.


Structure of the malB region in Escherichia coli K12. II. Genetic map of the malE,F,G operon.

Starting with a strain containing a malK-lacZ fusion, a series of lambda plaque-forming phages which carry varying amounts of the malE,F operon have been isolated. We have used these phages to construct a deletion map of the malE,F operon. The construction of this deletion map has led to the identification of a new gene, malG. The malG gene is located distal to malF. The malG gene product is a protein required for the active transport of maltose and maltodextrins.


The nucleotide sequence of the mitochondrial genome of a spontaneous "petite" mutant of yeast.

The nucleotide sequence of the repeat unit of the mitochondrial genome of a spontaneous petite mutant of S. cerevisiae is reported. The sequence provides direct information on the AT-spacers and GC-clusters of the mitochondrial genome of yeast.


Var1 is associated with the small ribosomal subunit of mitochondrial ribosomes in yeast.

We show that the mitochondrial protein known as Var1 is identical with the ribosome-associated protein previously identified as a product of mitochondrial protein synthesis. Although indirect evidence suggests that Var1 is not involved in ribosome biosynthesis, a definite conclusion has to await further investigation.


Tetracyclines and host defence mechanisms. Doxycyclinepolymethaphosphate sodium complex (DMSC) compared to doxycycline with regard to influence on some host defence mechanisms.

A new doxycycline preparation, doxycycline polymethaphosphate sodium complex (DMSC), was compared to doxycycline in a cross-over study on six volunteers. The serum levels attained were of the same magnitude, but DMSC was shown to influence the serum bactericidal effect to a lesser degree. In vitro investigations of the influence on chemotaxis showed that DMSC even in high concentrations did not interfere with the spontaneous or induced migration to the same extent as doxycycline.


Reliability of thermal transitions for characterizing DNA from micro-organisms.

Data from thermal transitions were evaluated for their usefulness in detecting similarities in the deoxyribonucleic acid (DNA) of micro-organisms. Levels of reproducibility were determined for thermal transition analysis; methods of purification of DNA and the solvents, pH, and temperature intervals used during thermal transitions did not greatly affect the reproducibility of the values obtained. The shape of the thermal transition curve is a stable property of a given kind of DNA, and this property can be described quantitatively and with satisfactory precision.


Decreased conjugation efficiency by Fla-mutants of Escherichia coli K-12 bearing F-like plasmids.

Fla-, Pil-mutants of Escherichia coli K-12 were found to have decreased transfer efficiency of F-like resistance plasmids as compared to the parent strains. This was accompanied by decreased production of conjugation pili and decreased resistance level to some, but not all, of the antibiotics to which resistance was conferred. There was no reduction in pilus production or transfer efficiency in any of the mutants when the plasmid was F'gal. This host-mediated influence on conjugation pilus production is discussed with reference to a possible loss of cell envelope integrity which causes the simultaneous loss of all cellular appendage structures.


Surface colony growth in a controlled nutrient environment. 1 The exponential law.

An apparatus designed to study the growth rates of surface colonies in constant conditions, i.e. not affected by nutrient diffusion as in a closed Petri dish, is described. In contrast to classical experiments in closed systems, an exponential growth of colony radius is obtained for a period of more than 72 h. Nutrient concentration gradients are shown to be eliminated by analytical techniques.


Surface colony growth in a controlled nutrient environment. 2 The effect of ethanol.

The effect of feed alcohol in an apparatus designed to study growth rates of surface colonies in constant nutrient conditions was studied. The results obtained indicate that departure from exponential growth in normal conditions is due to accumulation of alcohol in the system.


Effectiveness of instructional computers in teaching basic medical sciences.

The present study was designed to investigate the effectiveness of computer-based PLATO IV basic medical science lessons. Effectiveness was operationalized in terms of increased performance on basic medical science examinations for those medical students who had used the lessons when compared to those students who had not. Usage of the PLATO lessons was quantified as 'minutes of use' of the relevant lessons. Data were gathered in 1976-77 from first-year medical students at two sites, both under the auspices of one college of medicine. Usage of PLATO lessons and subsequent performance on three subtests from three different examinations were analysed. The findings from the current study offer encouragement that use of PLATO basic medical science materials contribute to increased performance on subsequent examinations.


Vincristine and prednisone vs vincristine, L-asparaginase, and prednisone for second remission induction of acute lymphocytic leukemia in children.

Second remission induction rates for vincristine and prednisone alone (VP) and vincristine, L-asparaginase, and prednisone (VLP) are compared for children with acute lymphocytic leukemia. No evidence of a significant difference between the second induction complete remission rate for VP (78.6%) and VLP (73.7%) was found. Duration of first remission and prognostic group at initial diagnosis (defined on the basis of age and white blood count at initial diagnosis) are shown to be significant prognostic factors for second remission induction; and three second remission induction risk groups are defined on the basis of these two factors. Periodic reinforcement with prednisone in first remission does not appear to lower second induction complete response (CR) rates for VP. There was no evidence of a significant difference in the frequency of occurrence of severe toxicity between the VP and VLP regimens.


Treatment of advanced head and neck cancer by means of radiation therapy plus chemotherapy--a randomised trial.

Fifty-eight patients with advanced head and neck cancer were entered into a randomised trial comparing radical radiation therapy to the primary tumour and associated lymph node areas with a combination of radiation therapy plus chemotherapy. The distribution of tumour types and stages was similar in the two treatment groups. The response rates to radiation therapy alone (50% complete plus parital response) and to radiation therapy plus chemotherapy (60% complete plus partial response) were not significantly different. However, a significant difference in survival was found between the two groups. The median duration of survival for the patients treated by means of radiation therapy alone was 18 weeks; that for the combined therapy was 36 weeks. The combination of radical radiation therapy plus intermittent high-dose chemotherapy was well tolerated and appears to be an approach that warrants further trial.


[Comparative study of the protein makeup in diploid and haploid forms of Saccharomyces and Pichia].

The rates of growth, biomass accumulation, and electrophoretic spectra of mobile cytoplasmic proteins were studied with nonisogenous haploid and diploid cultures of Saccharomyces cerevisiae and Pichia guilliermondii as well as with isogenous haploid-diploid pairs of Saccharomyces cerevisiae and Pichia pinus. On a mineral medium with glucose, differences in these parameters in various yeast strains were found to be due to the genotype of a strain rather than to ploidy: nonisogenous haploid and diploid cultures displayed considerable and random variability of these properties while no differences were found in isogenous haploid-diploid pairs. Studies on solubility of protein fractions in various solvents made it possible to reveal differences connected with ploidy, namely: both in nonisogenous and isogenous haploid-diploid systems, the content of the water-soluble fraction decreased in diploid cultures.


E. coli galactose-1-phosphate uridyl transferase: N-terminal and C-terminal sequences.

A modified procedure for the purification of E. coli galactose-1-phosphate uridyl transferase (E.C. 2.7.6.12) was developed which reproducibly gives pure enzyme. The purified enzyme was shown to be a dimeric protein with a subunit molecular weight of 41,000 and its amino acid composition and content of free sulfhydryl groups were determined. The N-terminal and C-terminal amino acid sequences were found to be NH2-thr-gln-phe-asn-pro-val-asp and -ser(val leu)-ala-COOH respectively. This N-terminal sequence allowed the identification of the start of the transferase gene in the DNA sequence determined by GRINDLEY. Furthermore it appears to define a nine base intercistronic region between the epimerase and transferase genes.


The development of a "Microtitre" fluctuation test for the detection of indirect mutagens, and its use in the evaluation of mixed enzyme induction of the liver.

The "Microtitre" Fluctuation test recently introduced for the detection of direct mutagens has been adapted for the detection of indirect mutagens through the incorporation of an "S9-mix" metabolic system. It compares favourably with Greens' original method for the detection of a range of chemical mutagens. The technique has been employed in the evaluation of mixed enzyme induction using phenobarbitone and beta-naphthoflavone (benzoflavone), as a safe substitute for Aroclor-1254. The post-mitchondrial preparations from rats induced with the combined inducers had a similar "metabolic competence" to those derived from Aroclor induced animals. Such a combination would therefore provide a useful alternative to Aroclor-1254 for routine screening. It was found that the level of "S9" present in the metabolic system greatly affected the quantitative mutagenic response. This varied considerably from chemical to chemical and underlined the need for such preliminary investigations in routine screening.


Relative effectiveness of the 300--320 NM spectral region on sunlight for the production of primary lethal damage in E. coli cells.

Cell inactivation by sunlight exposure has been studied in E. coli CSR 603 (uvrA recA phr), a K12 derivative which is deficient in all known repair systems. Under suitable conditions, unfiltered sunlight inactivates these cells to 10(-3) survival within 30 sec. The effects of unfiltered sunlight have been compared with those of sunlight filtered through 1-cm layers of aqueous caffeine solutions ranging in concentration from 1 to 20 mg/ml. In the wavelength region of solar emission below 320 nm, which is most critical for DNA damage, the transmission of these liquid filters changes from 10 to 90% within 8-nm intervals. Thus our results permit minimum estimates for the fraction of lethal lesions produced by the solar spectrum below certain wavelenghts. In an experiment analyzed in this manner more than 80% of primary lethal lesions are caused by wavelengths less than 321 nm, and more than 50% by wavelengths less than 306 nm, while the contribution of wavelengths greater than 380 nm to primary lethal damage is below 1%.


Mutation induction by thymine deprivation in Escherichia coli B/R. II. Mutation in the repressed and derepressed tryptophan operon.

True Trp+ reversions are induced by thymine deprivation in cells with repressed trp operons as efficiently as in derepressed cells. At least part of the mutations are fixed during thymine starvation, i.e. in the absence of net DNA synthesis. The hypothesis is put forward that thymineless mutagenesis is due to repair-replication under limited concentrations of 5'-dTTP, performed by an inducible error-prone "DNA-polymerizing activity" on single-strand gaps.


Mechanism of the lethal and mutagenic effects of phenoxyacetic acids in Saccharomyces cerevisiae.

MCPA and salicylic acid, two compounds with similar structures and almost the same dissociation pattern, were tested for lethal and mutagenic effects on, and uptake by, cells of Saccharomyces cerevisiae strain rad18. The results obtained with the two compounds were similar, suggesting a common mechanism of action. It is proposed that they act by increasing the concentration of hydrogen ions within the cell, so that killing and mutation occur. Mutations were induced only when killing reached 95--99%. The compounds are considered weak mutagens for yeast cells. The methyl ester of MCPA also induced killing and reverse mutation, but only at concentrations about 100 times higher than for the undissociated acid. MCPA methyl ester did not increase the number of revertants in the Salmonella/liver microsome test. It is suggested that the effects of the methyl ester of MCPA depends on the ester being hydrolysed to the acid by yeast cells and the liver microsome preparation.


Mutagenicity of 8-ethoxycaffeine in vitro. Induction of point mutations in the Salmonella/microsome test and of sister-chromatid exchanges as well as chromosomal aberrations in Chinese hamster ovary cells (CHO line).

The caffeine derivative 8-ethoxycaffeine (EOC) was tested in 3 different test systems in vitro. Each experiment was carried out with and without S9 mix. Incubation temperatures were 20 and 37 degrees C. (1) In the Salmonella/microsome test, EOC behaved as a pro-mutagen in the Salmonella typhimurium strain TA1535. No mutagenic activity was found in experiments without S9 mix. The influence of temperature was negligible. The mutagenic activity of EOC depended mainly on the mammals used to prepare the S9 fraction and on the agents given to them to induce liver enzymes. (2) EOC did not induce sister-chromatid exchanges in cell cultures, either at 20 or at 37 degrees C. (3) On the other hand, EOC induced chromosomal aberrations when the cells were incubated at 37 degrees C without S9 mix.


Spontaneous mutagenesis in Escherichia coli strains lacking 6-methyladenine residues in their DNA: an altered mutational spectrum in dam- mutants.

The mutational spectrum at the lacI locus in a dam-4 strain of Escherichia coli was examined. The observed 20-fold increase in spontaneous mutagenesis in a dam- strain was found to be due to base substitutions, primarily transitions, which had increased 140-fold. Using the trpE997 mutation it was found that the dam mutations also resulted in an increase in frameshift mutagenesis. The mutational spectrum of dam- strains was similar to that found with strains carrying the mutH, mutL, mutS and uvrE mutations thought to result in a defect in the repair of mismatched bases. These results are taken to be consistent with, and to support the hypothesis that, dam- strains are deficient in a post-replicative error-avoidance pathway which allows the directed elimination of mismatch lesions by a mechanism in which parental strands are recognized by their level of DNA methylation.


Repair promoted by plasmid pKM101 is different from SOS repair.

In E. coli K12 bacteria carrying plasmid pKM101, prophage lambda was induced at UV doses higher than in plasmid-less parental bacteria. UV-induced reactivation per se was less effective. Bacteria with pKM101 showed no alteration in their division cycle. Plasmid pKM101 coded for a constitutive error-prone repair different from the inducible error-prone repair called SOS repair. Plasmid pKM101 protected E. coli bacteria from UV damage but slightly sensitized them to X-ray lesions. Protection against UV damage was effective in mutant bacteria deficient in DNA excision-repair provided that the recA, lexA and uvrE genes were functional. Survival of phages lambda and S13 after UV irradiation was enhanced in bacteria carrying plasmid pKM101; phage lambda mutagenesis was also increased. Plasmid pKM101 repaired potentially lethal DNA lesions, although wild-type DNA sequences may not necessarily be restored; hence the mutations observed are the traces of the original DNA lesions.


DNA--benzo[a]pyrene adducts formed in a Salmonella typhimurium mutagenesis assay system.

The DNA adducts formed in Salmonella typhimurium when bacteria are incubated with radioactive benzo[a]pyrene and liver microsomal enzymes from several sources has been investigated. When enzyme preparations from Aroclor I254 or 3-methylcholanthrene induced C57BL/6N (B6) mice were used to mediate activation, the predominant product was an adduct between the 10 position of 7 beta, 8 alpha-dihydroxy-9 alpha, 10 alpha epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene and the N-2 position of deoxyguanosine. Similar results were obtained with human liver and with Aroclor-induced rat-liver enzyme preparations. This adduct is also the major DNA product previously found when human tissues or certain rodent cells were incubated with benzo[a]pyrene. On the other hand, when activation of benzo[a]pyrene was mediated by a phenobarbital-induced B6 mouse-liver enzyme preparation, the extent of binding was quite low and the profile of DNA adducts in S. typhimurium DNA was quite different. Thus, under appropriate conditions, the activation and DNA binding of benzo[a]pyrene inthe microsome mediated S. typhimurium mutagenesis assay generally resembles that seen in intact mammalian cells. Caution must be exercised, however, in the choice of microsome-activation systems.


Mutagenesis of Saccharomyces cerevisiae by sodium azide activated in barley.

Concentrated dialysate of the extract prepared from barley seeds treated with sodium azide increased up to 100--200 times the frequency of forward mutations to cycloheximide resistance in the excision-deficient UV-sensitive heploid strain rad2-5 of Saccharomyces cerevisiae, when applied to growing cells in complete medium at pH 4.2. Only a slight increase of mutation frequency (less than 4 times) was found in the haploid RAD+ strain treated in the same way as well as in haploid RAD+ and rad2-5 strains treated directly by sodium azide. In contrast with the barley-activated sodium azide, UV irradiation was more effective in the induction of cycloheximide resistance in the RAD+ strain than in the RAD2-5 mutant. The dialysate from azide-treated barley seeds, applied at both pH 4.2 and pH 9, also significantly increased the frequency of locus-specific suppressor mutations to isoleucine independence and -- to a lesser extent -- reversions and/or gene conversions in the trp5 locus in growing cells of the diploid strain D7. The dialysate was also mutagenic in resting cells of strains D7 and rad2-5 but with lower effectiveness.


Mitochondrial mutagenesis in Saccharomyces cerevisiae. II. Methyl methanesulphonate and diepoxybutane.

In Saccharomyces cerevisiae, methyl methanesulphonate and diepoxybutane produced efficiently lethal, as well as mutagenic, damage in nuclear DNA. However, in the same conditions, these agents did not induce cytoplasmic petite mutations and poorly induced point mutations (resistance to erythromycin and chloramphenicol) in mitochondrial DNA. Possible reasons for these differences are discussed.


Enumeration of 6-thioguanine-resistant peripheral blood lymphocytes in man as a potential test for somatic cell mutations arising in vivo.

An autoradiographic method to enumerate variant 6-thiogunanine-resistant (TGr) peripheral blood lymphocytes (PBLs) that occur in vivo in man is described. Variant cells are detected in PBL cultures stimulated to tritiated thymidine (3HTdr) incorporation in vitro with phytohemagglutinin (PHA) in the presence of TG. Cells with the naturally-occurring Lesch--Nyhan (LN) mutation served as prototype-variant cells. PBLs from a LN hemizygous male were found to be resistant to TG inhibition of PHA-stimulated 3HTdr in corporation in vitro while a LN heterozygous female was found to be a mosaic with 2/1000 PBLs resistant to 2 X 10(-4) M TG. Experiments with artificial mixtures of LN and normal PBLs showed that the LN cells were virtually all detectable even when present in low frequency (10(-5)). TGr PBLs were found in healthy non-LN individuals at median frequencies of 1.0 X 10(-4) and 1.1 X 10(-4) when determined at 2 X 10(-3) M TG and 2 X 10(-4) M TG respectively. Their frequencies were not age-related. TGr PBL-variant frequencies (Vf's) were determined in 47 cancer patients who were being treated with cytotoxic agents that are known to be mutagens. The median TGr PBL Vf determined at 2 X 10(-3) M TG in cancer patients was 2.2 X 10(-4) while, when determined at 2 X 10(-4) M TG, it was 8.5 X 10(-4). The distribution of Vf's for the treated cancer-patient group differed from that for the normal control group in that more than half of the treated cancer patients had TGr PBL Vf's greater than the highest seen for controls. Unlike those of the normal controls, the TGr PBL Vf's of treated cancer patients differed if determined at 2 X 10(-3) M TG and 2 X 10(-4) M TG, a behavior that suggested partial resistance and mimicked that seen with LN TGr PBLs. PBLs resistant to 2,6-diaminopurine (DAPr) were not found in two individuals, although the TGr PBL Vf was elevated in one. TGr PBL Vf's were greatly elevated under conditions of in vivo selection in patients receiving purine-analogue immunosuppressive therapy. The TGr PBL enumerative assay system is presented as one of potential value to detect somatic cell mutations occurring in vivo in man.


Reversal of sodium-azide mutagenicity by liver preparations and by gastric juice.

Sodium azide was found to be mutagenic for Salmonella typhimurium by inducing base-pair substitutions that were not enhanced by pKM101 plasmid (R factor). However, the mutagenicity of sodium azide was decreased by enzyme proteins contained in rat-liver post-mitochondrial fractions, depending on the NADPH-generating system. Pre-incubation with human gastric juice also decreased azide mutagenicity. These metabolic effects might explain the conflicting nature of the mutagenicity and carcinogenicity tests reported in the literature. Laboratory reagents containing 0.1% sodium azide as a preservative showed the expected patterns of mutagenicity and of metabolic deactivation, and no aspecific interaction could be detected between azide and the various components, including proteins, of the reagents tested.


Mutagens in the feces of 3 South-African populations at different levels of risk for colon cancer.

The incidence of mutagens in the feces of 3 South-African populations at different risk levels for colon cancer has been determined. Lyophilized fecal samples were extracted with ether and the mutagenicity of the extracts determined using the Salmonella/mammalian microsome mutagenicity test. 19% of the samples from urban white South-Africans, a population at a high risk for colon cancer, were mutagenic using Salmonella typhimurium strain TA100. This incidence was significantly greater (p less than 0.001) than the incidence of mutagen excretion in the low-risk populations of urban blacks (2%) and rural blacks (0%). This pattern was also obtained using Salmonella typhimurium strain TA98. The incidence of mutagen excretion for urban whites was 10%, as compared to 5% and 2% for urban and rural blacks, respectively.


Methodology for the testing of food dyes for genotoxic activity: experiments with red 2G (C.I. 18050).

A methodology for investigating genotoxicity of food colours using the fluctuation and DNA-repair assays with bacteria is described. In addition, a liquid repair test, developed to permit incorporation of microsomes and the quantitative estimation of cell viability, has been characterised with a number of positive control agents. Results obtained in these systems suggest that the food colour Red 2G induces repairable DNA damage and base-substitution mutation, but only in the presence of a rat-liver microsomal preparation. The significance of the data in the light of other toxicological information is discussed.


The L-arabinose-resistance test with Salmonella typhimurium strain SV3 selects forward mutations at several ara genes.

A new assay has been described for mutagenicity testing using an L-arabinose-sensitive strain of Salmonella typhimurium. The test strain SV3 and several L-arabinose-resistant mutants selected therefrom are characterized in the present study by 3 different criteria: inhibition of growth by L-arabinose, accumulation of keto-sugars, and activities of the enzymes involved in L-arabinose catabolism. Strain SV3 (ara-531) shows high levels of inducible L-arabinose isomerase (EC 5.3.1.4) and L-ribulokinase (EC 2.7.1.16) activities, but is deficient in L-ribulose-5-phosphate 4-epimerase (EC 5.1.3.4), the enzyme encoded in Escherichia coli by gene D in the araBAD operon. Addition of L-arabinose to SV3 growing in glycerol or casamino acids stops growth. D-Glucose only partially reverses this inhibition. Reversion of the ara-531 mutation restores different levels of epimerase activity and resistance to L-arabinose. However, the great majority of the L-arabinose-resistant mutants do not utilize L-arabinose. The physiological and enzymatic properties of these L-arabinose non-utilizing mutants suggest that L-arabinose resistance is due to forward mutations in at least 3 other genes, araA, araB and araC, blocking steps prior to L-ribulose 5-phosphate accumulation.


Statistical tests for recessive lethal-carriers.

This paper presents a statistical method for testing whether a male mouse is a recessive lethal-carrier. The analysis is based on a back-cross experiment in which the male mouse is mated with some of his daughters. The numbers of total implantations and intrauterine deaths in each litter are recorded. It is assumed that, conditional on the number of total implantations, the number of intrauterine deaths follows a binomial distribution. Using computer-simulated experimentation it is shown that the proposed statistical method, which is sensitive to the pattern of intrauterine death rates, is more powerful than a test based only on the total number of implant deaths. The proposed test requires relatively simple calculations and can be used for a wide range of values of total implantations and background implant mortality rates. For computer-simulated experiments, there was no practical difference between the empirical error rate and the nominal error rate.


Platinum(II) complexes generate frame-shift mutations in test strains of Salmonella typhimurium.

cis-Diamminodichloroplatinum(II) (cis-PDD) and diaquoethylenediamineplatinum(II) induce histidine revertants in Salmonella typhimurium strains TA98 (frame-shift mutation) and TA100 (base-pair substitution mutation). A linear dose--response relationship is found with cis-PDD acting on TA98 and TA100. Salmonella typhimurium strains TA1535, TA1537 and TA1538 are not sensitive to the mutagenic action of cis-PDD. All 5 strains are sensitive to the toxic effect of cis-PDD. Platinum(II) complexes induce mutations (frame-shift or base-pair substitution) only in strains carrying the R-factor plasmid.


Recombinogenicity and mutagenicity of saccharin in Saccharomyces cerevisiae.

Diploid yeast grown in the presence of a commercial lot of saccharin exhibited reproducible, dose-dependent increases in intergenic and intragenic recombination, and mutation. Cells grew to nearly the same titer in media without saccharin and containing 2 or 20 mg saccharin/ml, although cell viability was somewhat reduced in saccharin-containing media. At the high test dose of 100 mg/ml, titers and cell viability were more markedly lowered. Differences between this study and previous (negative) tests of saccharin in yeast are described.


Derivatives of side-chain hydroxylated nitrosamines direct acting mutagens in Salmonella typhimurium.

Methyl-(beta-tosyloxyethyl)nitrosamine and 3-methyl-4,5-dihydro-1,2,3-oxadiazolium tosylate are potent direct acting mutagens in the Ames assay, as is N-nitrosoprolinyl tosylate. These compounds are derived from beta-hydroxylated nitrosamines. The closely related methyl-(gamma-tosyloxypropyl)nitrosamine is not mutagenic without activation. These data are consistent with the chemical behavior of these substances, which suggest that suitable derivatives of beta-hydroxylated nitrosamines, such as O-sulfates, may be direct-acting biological alkylating agents.


Testing of some permitted food colours for the induction of gene conversion in diploid yeast.

12 permitted food colours in use were screened for geno-toxicity. Mitotic gene conversion in Saccharomyces cerevisiae was used as the end-point. Each food colour was tested in stationary-phase as well as log-phase cells but without microsomal activation. These food colours did not cause any increase in mitotic gene conversion in diploid yeast BZ 34.


Mutagenic effects of cadmium on mammalian oocyte chromosomes.

When female golden hamsters were treated with cadmium chloride at the oogenesis stages of diakinesis/metaphase I to metaphase II, oocytes with the chromosomal complements of hyperhaploidy and diploidy, as well as oocytes at the anaphase-I stage, were observed. Oocytes of this species were especially sensitive to cadmium. Chromosome analysis of metaphase-II oocytes seems to be a useful method for the screening of mutagenicity of environmental contaminants in mammalian germ cells in vivo.


Cytogenetic studies in patients treated with penicillamine.

Cytogenetic studies were performed on bone-marrow cells from 11 patients with rheumatoid arthritis treated with penicillamine. One of the patients was studied while developing a granulocytopenia and thrombocytopenia. The findings show that penicillamine had no chromosome-damaging effect as estimated by the micronucleus test and by the number of structural chromosomal aberrations.


Failure of high-dose vitamin C (ascorbic acid) therapy to benefit patients with advanced cancer. A controlled trial.

One hundred and fifty patients with advanced cancer participated in a controlled double-blind study to evaluate the effects of high-dose vitamin C on symptoms and survival. Patients were divided randomly into a group that received vitamin C (10 g per day) and one that received a comparably flavored lactose placebo. Sixty evaluable patients received vitamin C and 63 received a placebo. Both groups were similar in age, sex, site of primary tumor, performance score, tumor grade and previous chemotherapy. The two groups showed no appreciable difference in changes in symptoms, performance status, appetite or weight. The median survival for all patients was about seven weeks, and the survival curves essentially overlapped. In this selected group of patients, we were unable to show a therapeutic benefit of high-dose vitamin C treatment.


Financing graduate medical education.

The direct costs of residency training in the United States are over $1 billion per year. These educational programs have been organized predominantly around hospital services and supported by hospital revenues. Pressure has been increasing to reduce the rate of increase in hospital expenditures or costs or both. This article describes alternative methods for financing graduate medical education. Debate over the current sources of financing reveals several troublesome issues: the presence of residents allegedly decreases the productivity of professionals and leads to overusage of ancillary services, proposed methods to pay for faculty salaries and services have created confusion and concern, and the financing of ambulatory-care training has been insufficient and poorly coordinated. The medical-education community must resolve these professional and educational problems so that financing issues can be debated and properly defended.


Warfarin sodium versus low-dose heparin in the long-term treatment of venous thrombosis.

Acute deep-vein thrombosis is usually treated with intravenous heparin for a number of days, then with oral anticoagulants for weeks to months. We have compared adjusted-dose warfarin sodium with fixed low-dose subcutaneous heparin in the prevention of recurrent deep-vein thrombosis. Sixty-eight patients with acute deep-vein thrombosis confirmed by venography were treated with intravenous heparin and then randomized to secondary prophylaxis. Nine of 35 patients receiving subcutaneous heparin, but none of 33 receiving warfarin sodium, had new episodes of objectively documented venous thromboembolism (P = 0.001). Seven patients on warfarin sodium experienced bleeding complications (of which four were major), as compared with no patients receiving subcutaneous heparin (P less than 0.005). Thus, adjusted-dose warfarin sodium is more effective than low-dose subcutaneous heparin in preventing recurrent venous thromboembolism, but its use is accompanied by a significant risk of bleeding.


Detection of circulating antigen of Aspergillus fumigatus in sera of mice and rabbits by enzyme-linked immunosorbent assay.

Circulating antigen of Aspergillus fumigatus was demonstrated in the sera of experimentally infected, cortisone-treated mice and rabbits by enzyme-linked immunosorbent assay (micro-ELISA), confirming earlier results where fungal antigen had been detected by counter-immunoelectrophoresis (CIE). Peaks of detection of circulating antigen by CIE and micro-ELISA in mice were not simultaneous suggesting that the nature of the predominant antigens may have altered during the course of infection. CIE failed to detect fungal antigen in infected rabbits whereas micro-ELISA monitored antigenemia until death. Both CIE and micro-ELISA demonstrated the rapid clearance of intravenously inoculated Aspergillus-antigen from the rabbit circulation.


Prevalence of pathogenic fungi in the toe-webs and toe-nails of diabetic patients.

100 diabetic and 100 diabetes-free patients were mycologically examined for the presence of pathogenic fungi in their toe-webs and toe-nails. While there were clinical signs of presumed mycotic infection in 73 of the diabetic and in 66 of the non-diabetic subjects, the examination of the KOH-treated specimens revealed fungal elements in only 70 of the former and in 53 of the latter group. Isolation of the causative agent was possible in 57 of the diabetic patients (T. rubrum in 46%, C. albicans in 31%, T. mentagrophytes in 21% and E. floccosum in 3%) and in 40 of the control group (T. rubrum 57,5%, T. mentagrophytes 35%, C. albicans 5%, E. floccosum 2,5%). An interesting correlation was observed between the level of blood sugar and the percentage of positive fungal findings, the patients with more than 3000 mg/ml being 100% afected. C. albicans was found in a lower percentage in non-diabetic patients. The in vitro test of the sensitivity of the isolated organisms to the antidiabetic drugs, received by the patients, showed no significant anti-fungal activity.


Comparison of the growth of virulent and attenuated strains of Candida albicans in the kidneys of normal and cortison-treated mice by chitin assay.

Candida albicans strain 22114 was avirulent for mice compared with strain 19321 in that, administered intravenously, 10(6) blastospores of 22114 failed to kill whereas 10(6) blastospores of 19321 produced 100% mortality. Cortisone treatment rendered mice susceptible to killing by 22114. Chitin assay showed that cortisone stimulated the growth of both strains in the mouse kidney. Growth of 19321 was increased up to five-fold and 22114 up to forty-fold. The strains may have differential susceptibility to cortisone-sensitive host defences which control fungal growth in vivo.


Prenatal exposure to chemical carcinogens and its effect on subsequent generations.

That exposure of pregnant animals to chemical carcinogens results in the occurrence of tumors in the progeny is well documented. Evidence has been accumulated on at least 38 chemicals pertaining to different chemical groups. The experimental evidence was followed by observations in humans regarding the increased risk of cancer in daughters of women who received stilbestrol during pregnancy. Additional experimental evidence is accumulating on the possibility that exposure during pregnancy results in an increased incidence of tumors for more than one generation of untreated descendants. Studies done on mice with DMBA and on rats with MNU and ENU showed that exposure to the carcinogens during pregnancy resulted in a high incidence of tumors in animals of the first generation and in an increased incidence of tumors at specific sites in untreated animals of the second and third generations.


Perinatal viral carcinogenesis: the role of immunity.

The perinatal period cumulates conditions favorable to carcinogenesis that comprise high cellular multiplication rates, unstable homeostasis, and immune incompetence. The placenta allows the passage of various antigens including oncogenic viruses that have immunogenic or tolerogenic effects on the fetus. According to the structural type in different species, the placenta also transfers a diversity of maternal antibodies that protect efficiently the unborn progeny. However, in the postnatal period, the infant deprived of maternal antibodies and still incompetent to produce sufficient levels of immunoglobulins is highly susceptible to viral carcinogenesis. In an experimental system, newborn rats were totally protected against viral leukemogenesis by prenatal immunization of mothers with either live or inactivated leukemia virus. The routes of transfer and the comparative efficiency of serum and milk immunoglobulins of different classes to neutralize the virus were examined. The passage of antibodies under conditions of maternal immunosuppression was also studied.


Transplacental and neonatal induction of neurogenic tumors in mice: comparison with related species and with human pediatric neoplasms.

The literature on chemical induction and natural occurrence of neurogenic tumors in mice and some unpublished data from our laboratories are reviewed. Neurogenic tumors are a minor component of the total tumorigenic response of mice to alkylating agents such as ENU and MNU. In comparison with rats, a given dose of ENU induces a much lower incidence of neurogenic tumors in mice, and the mean latency is much longer than in rats. Although most neurogenic tumors induced by ENU in mice by either transplacental or direct postnatal exposure are of glial or Schwann cell origin, as in rats, and occur most frequently in the cerebrum or cranial nerves, respectively, medulloblastomas of the cerebellum also occur in treated mice. Transplacental and neonatal exposure to ENU were much more effective in inducing neurogenic tumors than treatment later in life. Ependymomas were not seen in mice, although they are common in ENU-treated rats. Neuroblastoma of the adrenal medulla, a common human pediatric tumor, has not been induced to either species, but it does occur spontaneously in mice. The induction by ENU of medulloblastomas demonstrates that this rodent equivalent of an embryonal tumor of the human nervous system can result from exposure to exogenous chemical agents.


Neoplastic response of mouse tissues during perinatal age periods and its significance in chemical carcinogenesis.

A series of studies pertaining to perinatal carcinogenesis have been reviewed. Their main objective was development and definition of a sensitivity biologic model for carcinogenicity screening. Data were summarized on factors modifying the carcinogenic response of various tissues following transplacental, neonatal-infant, or adult exposure of (B57BL/6J X C3HeB/FeJ)F1 mice to a single administration of ENU. In addition, tumor response of mice treated during specific perinatal age periods with DEN, BP, aflatoxin B1, benzidine . 2HCl, DDT, dieldrin, and safrole were analyzed. The results revealed that the age of the animals at the time of carcinogenic exposure has been the most effective modulator of carcinogenesis in liver, lung, stomach, ovary, and lymphoreticular tissues. Infancy proved to be the most susceptible period to carcinogenesis as demonstrated by a great variety of tissues that responded to treatment and the incidence of tumors which developed. Depending on the nature of carcinogen, variation in organ sites undergoing carcinogenesis was considerable, apparently due to difference in their enzymatic competence to activate and metabolize the agent. Thus a single treatment with ENU, a spontaneously activated type of procarcinogen, induced 59 primary types of tumors in 22 tissues. In contrast, treatment of infants by procarcinogens requiring enzymatic activation led to development of tumors only at a limited number of tissue sites. However, regardless of the type of carcinogen used, the liver consistently responded with development of tumors. Detailed morphologic and biologic evaluations of the induced liver tumors demonstrated in addition to the benign neoplastic variety, the presence of the frank malignant tumors. The character of tumors was dependent not only on carcinogenicity of the agent used but also on the age of mice at the time of carcinogenic treatment. Perinatally induced primary liver tumors showed greater tendency to metastasize and were more readily transplantable into an isogeneic host than those induced at later age periods. Data showed the advantage of prenatal and/or postnatal treatment in combination of life-long exposures to test agents as a more sensitive bioassay system in comparison with solely postweaning treatment. Because the early age period is the most sensitivity life phase to carcinogenesis, it appears to be a good model for prescreening various potential carcinogens, especially when only small amounts of test substances are available. The importance of the proper relationship of such bioassay to the other test systems regarding assessment of potential human risk has been emphasized.