Function of phospholipids in Escherichia coli. Characterization of a mutant deficient in cardiolipin synthesis. Screening of a collection of temperature-sensitive mutants of Escherichia coli for defects in phospholipid metabolism led to the isolation of a mutant deficient in cardiolipin synthesis. The defective gene, named cls, is closely linked to the trp marker and maps at about Minute 27 on the E. coli chromosome. After transfer of cls to a defined genetic background by transduction, the mutant has the following properties as compared to an isogenic wild type. Exponentially growing cells show a reduction in cardiolipin content by a factor of at least 15 (less than 0.2 mol % of the total phospholipids). A crude membrane fraction derived from the mutant is unable to synthesize cardiolipin from phosphatidylglycerol in vitro. The mutant has no distinctive phenotype regarding its growth properties, membrane-associated respiratory functions, or the ability to insert bacteriophage M13 coat protein into the cell envelope. The cls mutation confers a 5-times reduction in the turnover of the phosphate moiety of phosphatidylglycerol.


A new iron-containing superoxide dismutase from Escherichia coli. Escherichia coli B, grown under aerobic conditions, contains at least three distinct superoxide dismutases, which can be visualized on polyacrylamide gel electropherograms of crude soluble extracts of the sonically disrupted cells. Of these, the slowest migrating and the fastest migrating, respectively, have previously been isolated and characterized as manganese-containing and iron-containing enzymes. The enzyme form with medium electrophoretic mobility has now been purified to homogeneity. Its molecular weight is approximately 37,000 and it contains 0.8 atoms of iron/molecule and only negligible amounts of manganese. Like other iron-containing superoxide dismutases and unlike the corresponding manganienzymes, it is inactivated by EDTA plus H2O2. Its specific activity is comparable to that of the other superoxide dismutases of E. coli. Two types of subunits could be distinguished upon electrophoresis in the presence of sodium dodecyl sulfate. One of these migrated identically with the subunit obtained from the manganisuperoxide dismutase, while the other similarly appeared identical with the subunit from the ferrisuperoxide dismutase. This newly isolated enzyme thus appears to be a hybrid of the other two forms. In support of this conclusion, we observed that ultrafiltration or storage of the new superoxide dismutase gave rise to the mangani- and ferrienzymes on disc gel electrophoresis or isoelectric focussing.


Stereochemistry and mechanism of reactions catalyzed by tryptophanase Escherichia coli. Several beta replacement and alpha,beta elimination reactions catalyzed by tryptophanase from Escherichia coli are shown to proceed stereospecifically with retention of configuration. These conversions include synthesis of tryptophan from (2S,3R)- and (2s,3s)-[3(-3H)]serine in the presence of indole, deamination of these serines in D2O to pyruvate and ammonia, and cleavage of (2S,3R)-and (2S,3S)-[3(-3H)]tryptophan in D2O to indole, pyruvate, and ammonia. A coupled reaction with lactate dehydrogenase was used to trap the stereospecifically labeled [3-H,2H,3H]pryuvates as lactate, which was oxidized to acetate for chirality analysis of the methyl group. During deamination of tryptophan there is significant intramolecular transfer of the alpha proton of the amino acid to C-3 of indole. To determine the exposed face of the cofactor.substrate complex on the enzyme surface and to analyze its conformational orientation, sodium boro[3H]hydride was used to reduce tryptophanase-bound alaninepyridoxal phosphate Schiff's base. Degradation of the resulting pyridoxylalanine to (2S)-[2(-3H)]alanine and (4'S)-[4'(-3H)]pyridoxamine demonstrates that reduction occurs from the exposed si face at C-4' of the complex and that the ketimine double bond is trans.


5-Dehydro-3-deoxy-D-arabino-heptulosonic acid 7-phosphate. An intermediate in the 3-dehydroquinate synthase reaction. 3-Dehydroquinate synthase was purified to homogeneity from Escherichia coli. It was found to be a single polypeptide chain of Mr = approximately 57,000. Reaction mixtures of pure enzyme and the substrate, 3-deoxy-D-arabino-heptulosonic acid 7-phosphate, were incubated for short times and treated with NaB3H4. The resulting 3-deoxyheptonic acid 7-phosphate was degraded with sodium periodate, and formic acid representing C-5 of the substrate was isolated. The presence of 3H in the formate corresponding to 15% of the enzyme was interpreted as indicating a 5-dehydro derivative of the substrate as an intermediate of the reaction. Quinic acid, resulting from reduction of 3-dehydroquinate with NaB3H4, was also isolated and degraded with periodate. The formate from C-4 of the quinate was unlabeled, indicating that 3,4-bisdehydroquinate is not an intermediate.


Zinc uptake and incorporation into proteins in T4D bacteriophage-infected Escherichia coli. The metabolism of Zn2+ in Escherichia coli infected with T4D bacteriophage and various T4D mutants has been examined. E. coli B infected with T4D, and all T4D mutants except T4D 12-, took up zinc ions at a rate identical to that of uninfected cells. E. coli B infected with T4D 12- had a markedly decreased rate of zinc uptake. The incorporation of zinc into proteins of infected cells has also been studied. T4D phage infection was found to shut off the synthesis of all bacterial host zinc metalloproteins while allowing the formation of viral-induced zinc proteins. The amount of zinc incorporated into viral proteins was affected by the absence of various T4D gene products. Cells infected with T4D 12-, and to a much less extent those infected with T4D 29-, incorporated the least amount of zinc into proteins, while cells infected with T4D 11- and T4D 51- incorporated increased amounts of zinc into the zinc metalloproteins. In cells infected with T4D 11- and 51- most of the zinc protein was found to be the product of gene 12. The marked effect of infection of E. coli with T4D 12- on both zinc uptake and zinc incorporation into protein supports the conclusion that T4D gene 12 protein is a zinc metalloprotein. Additionally, these observations have indicated that this metalloprotein interacts with host cell membrane.


In vivo distribution of phosphothioredoxin and thioredoxin in Escherichia coli. The phosphorylation state of thioredoxin was compared in intact cells and in crude extracts. In crude extracts, the extent of phosphorylation was 0.70 to 0.80 mol of phosphate per mol of thioredoxin, with approximately equal amounts of thioredoxin phosphorylated either on cysteinyl32 (formula: see text) or on cysteinyl35 (formula: see text). By comparison, the extent of thioredoxin phosphorylation in intact cells was nearly 1.0 with phosphate present almost exclusively on cysteine32. Nonphosphorylated thioredoxin was present as the reduced thiol form (formula: see text). These findings imply that (formula: see text) is the relevant in vivo species and that a mechanism is operative in crude extracts for transfer of phosphate from cysteine32 to cysteine35.


Synthesis and degradation of poly(A) in permeable cells of Escherichia coli. Poly(A) synthesis and degradation have been examined in Escherichia coli cells made permeable to nucleotides by treatment with toluene. Although newly synthesized poly(A) is normally rapidly degraded in this system, extraction of the soluble portion of the cell effectively eliminates this process without affecting poly(A) synthesis. Poly(A) synthesis in this system displays many properties associated with poly(A) synthesis by purified poly(A) polymerase in vitro including a lag in polymerization, stimulation by increased ionic strength, and a low Mg2+ optimum. As with the purified enzyme, this system uses both ADP and ATP as substrates, requires conversion of ATP to ADP, and is strongly inhibited by dADP, orthophosphate, and pyrophosphate. In contrast to the purified poly(A) polymerase, the permeable cell system displays some properties suggestive of in vivo poly(A) metabolism. Thus, the permeable cells require an endogenous RNA primer for activity, the poly(A) product remains with the cells, and the reaction is greatly stimulated by polyamines. This system should prove extremely useful for studies of poly(A) metabolism in E. coli. A surprising feature of these studies was the finding that mutant strains deficient in polynucleotide phosphorylase were unable to synthesize poly(A). The possible roles of polynucleotide phosphorylase and poly(A) in E. coli are discussed.


Escherichia coli dnaB protein. Affinity chromatography on immobilized nucleotides. The purification of the Escherichia coli dnaB protein by affinity chromatography on nucleotides bound to agarose is described. The dnaB protein, which contains an associated ribonucleoside triphosphatase activity (Wickner, S., Wright, M., and Hurwitz, J. (1974) Proc. Natl. Acad. Sci. U. S. A. 71, 783-787) binds to immobilized ATP, ADP, and UDP, but not to AMP. The type of linkage of ATP to agarose influences the adsorption, elution, and purification of the enzyme. Optimal purification is achieved using ATP bound to agarose via its oxidized ribose moiety. By this means, the dnaB protein can be obtained at least 95% electrophoretically pure after only three purification steps. The enzyme can be eluted from immobilized nucleoside-5'-di- and -triphosphates by ATP, ADP, and pyrophosphate, but not by AMP or orthophosphate. ADP and pyrophosphate, as well as the substrate ATP in high concentration are at the same time inhibitors of the ribonucleoside triphosphatase. The dnaB complementing and ribonucleoside triphosphatase activities could not be separated from each other by affinity chromatography, supporting the finding of others that they both reside on the same protein complex, namely a dnaB multimer. The results indicate that the dnaB protein binds to immobilized nucleotides by means of its ribonucleoside triphosphatase, and that at least the pyrophosphate moiety is essential for adsorption as well as elution of the enzyme.


The effect of methylmethacrylate on chemotaxis of polymorphonuclear leukocytes. The effect of methylmethacrylate on chemotaxis of polymorphonuclear leukocytes was evaluated by an in vitro method that involved migration of human leukocytes under agarose. Chemotactic factors produced during growth of Staphylococcus epidermidis, Staphylococcus aureus, and Escherichia coli remained chemotactically active in the presence of a methylmethacrylate concentration of 1.25 per cent, which was the highest tested. The methylmethacrylate also did not alter the activity of the chemotactic factor produced by zymosan activation of normal human serum. However, when methylmethacrylate was added to normal human serum prior to zymosan activation, a methylmethacrylate concentration of 0.312 per cent significantly depressed the subsequent zymosan-induced chemotactic activity and concentrations above 0.312 per cent abolished it. When methylmethacrylate was added to the polymorphonuclear leukocyte suspensions, there was significant depression of the migration of cells at a concentration of 0.312 per cent, and at concentrations of 0.625 and 1.25 per cent no leukocyte migration occurred.


On the stimulation of rat thymocyte 3-O-methyl-glucose transport by mitogenic stimuli. Pretreatment of rat thymus lymphocytes with N-ethyl-maleimide prevents the stimulation of 3-O-methyl-glucose transport by concanavalin A or ionophore A23187 but does not affect the ability of concanavalin A to induce a rapid increase in cellular Ca2+take. N-ethyl-maleikide added after concanavalin A amplifies rather than prevents the subsequent stimulation of 3-O-methyl-glucose transport. Incubation of thymocytes with concanavalin A produces a decrease of 43% in the apparent Ki for phloretin, a competitive inhibitor of 3-O-methyl-glucose transport, without affecting the apparent Km for the substrate. Similarly, very low concentrations of cytochalasin B inhibit concanavalin A-stimulated glucose transport preferentially, without markedly affecting the unstimulated transport rates. The similarity between concanavalin A-stimulated 3-O-methyl-glucose transport in thymocytes and insulin-stimulated glucose transport in adipose tissue, with particular emphasis on the effects of the modifying agents described in this paper, is discussed.


Effects of temperature and nutritional conditions on the mitotic cell cycle of Saccharomyces cerevisiae. Yeast cells were cultivated at different growth rates in a chemostat by alterations in the flow of the limiting nutrient glucose and in batch cultures where variations in growth rate were achieved by alterations in the composition of nutrients. It was observed that the stage in the cycle at which S-phase was completed varied with growth rate. The faster the growth rate, the earlier the stage in the cycle in which completion of S-phase occurred. When stage in the cycle  is converted into time before division it was observed that the time from completion of S-phase to cell division varied only slightly with growth rate except at extremely slow growth rates. Expansion of cell cycle transit time as the growth rate was slowed was achieved primarily by an expansion in time of the period from division to the completion of S-phase. In contrast, when cells were grown at different rates by alterations in the temperature of cultivation, completion of S-phase occurred at approximately the same stage in the cell cycle at all growth rates.


Comparison of micro-ID, API 20E, and conventional media systems in identification of Enterobacteriaceae. The Micro-ID, a new identification kit for Enterobacteriaceae, consists of 15 biochemical tests, with substrates and reagents impregnated in filter paper disks. A 0.2-ml amount of an organism suspension equal to a 0.5 McFarland standard is pipetted into each of the compartments. After 4 h of incubation and addition of potassium-hydroxide (KOH) to the Voges-Proskauer test, the color reactions are read according to the recommendations of the manufacturer. A five-digit octal code number is derived from each set of reactions from which an identification is derived by using a code book. In a single-blind, comparative study of the Micro-ID system with the API 20E system (Analytab Products Inc.) and conventional biochemical tube media, we found that the Micro-ID and the API 20E systems gave a 90% identification correlation when each was compared with the conventional tube media. A comparison of all three systems gave an 82% overall identification correlation. When the common tests of Micro-ID and API 20E were compared with conventional tube media, we found that the tests in the Micro-ID performed as well as or better than those of the API 20E. Certain groups of organisms, i.e., Citrobacter, Enterobacter, Proteus, Salmonella, and Serratia genera, were found to give low correlation on certain common tests. When using primary isolation MacConkey plates from the clinical laboratory, only 74% of the plates with Enterobacteriaceae had sufficient numbers of colonies of each enteric organism to produce the 0.5 McFarland inoculum density required. Problems concerning the misidentification of some organisms are discussed.


Evaluation of the Oxi/Ferm tube system for identification of nonfermentative Gram-negative bacilli. The Oxi/Ferm tube system designed for identification of oxidative-fermentative gram-negative bacteria was evaluated for identification of nonfermentative gram-negative bacilli by comparing it with the conventional system. The nine biochemical reactions used as the initial tests in the Oxi/Ferm tube system showed a close agreement with the same conventional reactions. However, the system was only 41% accurate to species or biotype for complete identification of 239 isolates which were well distributed in 48 species and biotypes and included organisms not listed in the Oxi/Ferm tube identification list. The system correctly identified 56% of the test organisms when the degree of identification was based on the manufacturer's guidance list. However, all isolates of Acinetobacter calcoaceticus, Bordetella bronchiseptica, Pseudomonas aeruginosa, P. diminuta, and group IIf were completely identified by the system.


Evaluation of the API 20E system for identification of nonfermentative Gram-negative bacteria. The API 20E system for Enterobacteriaceae, recently broadened to include identification of nonfermentative gram-negative bacteria, was evaluated and compared with the conventional method for complete identification of 221 nonfermenters, which were well distributed into 48 species or biotypes and included organisms not listed in the API 20E data base. The results of 16 tests common to both systems were in close agreement. The API 20E system correctly identified 71 (43%) of the 165 organisms included in the API 20E data base. However, almost 90% of Acinetobacter calcoaceticus, three species of Pseudomonas, and Bordetella bronchiseptica were correctly identified to species.


Rapid urea broth test for yeasts.

Rapid urea broth test for yeasts. A rapid, miniaturized, urea broth test useful for detecting urease activity of yeasts was compared to Christensen urea agar. All urease-producing yeasts tested were positive on both media; however, 60% were reactive in the urea R broth within 30 min, and the remainder were reactive within 4 h. This urea multiwell test may be useful as a rapid screening method for detecting urease-producing yeasts recovered from clinical specimens and as an adjunct test with other rapid methods of yeast identification.


Characterization and incidence of pigment production by human clinical group B streptococci. Pigment was produced in stab cultures by 97% of 297 group B streptococci isolated from human clinical specimens. The pigment, which was associated with a membranous cell fraction, showed a four-banded absorption spectrum similar to that of a carotenoid, with maxima at 435, 566, 485, and 525 nm. Addition of glucose to the growth medium suppressed pigment production in most strains. Only 37% of strains from bovine sources produced pigment.


Preparation of acid-fast microscopy smears for proficiency testing and quality control. A method is presented for preparing smears for proficiency testing and quality control in acid-fast microscopy. The work was prompted by the increased demand for acid-fast bacilli positive smears with characteristic microscopic appearance and among-smear uniformity.


Evaluation of Port-A-Cul transport system for protection of anaerobic bacteria. The protection of anaerobes in Port-A-Cul (PAC) transport system (Bioquest, Div. of Becton, Dickinson &Co., Cockeysville, Md.) tubes and vials was studied. Ten species of obligately anaerobic bacteria commonly isolated from clinical specimens were used to prepare simulated swab and fluid specimens in high and low concentrations. Samples in PAC tubes and vials were held for 2, 24, and 48 h at ambient temperature and in a refrigerator. In addition, samples of the simulated specimens were exposed to controlled anaerobic and aerobic conditions in vented tubes and vials, with and without PAC medium, at ambient and refrigerator temperatures. Viable bacterial colony counts from specimens in PAC tubes and vials used as recommended by the manufacturer were consistently greater than those from specimens exposed to the different controlled conditions. The protection in PAC was about equal for specimens with either high or low concentrations of bacteria. Protection of the anaerobes in PAC was more obvious with swab than with fluid specimens. Quantitative recovery of anaerobes from refrigerated PAC samples, with few exceptions, was comparable to that from PAC samples held at ambient temperature.


Standardization of the Analytab Enteric (API 20E) system to increase accuracy and reproducibility of the test for biotype characterization of bacteria. Procedures employing the Analytab Enteric (API 20E) system were standardized to improve the accuracy and reproducibility of the individual biochemical tests so that the system could be used to biochemically characterize bacteria for epidemiological studies. The standardized method and the method recommended by the manufacturer (routine method) were tested in parallel with 130 clinical isolates. Tests with 100 randomly selected clinical isolates demonstrated that the standardized method was more accurate and reproducible than the routine method. In addition, the standardized method accurately identified 24 of 30 clinical isolates which could not be identified with the routine method.


Biotyping of Serratia marcescens and its use in epidemiological studies. A Serratia marcescens biotyping system using eight carbon sources (benzoate, DL-carnitine, m-erythritol, 3-hydroxybenzoate, 4-hydroxybenzoate, lactose, D-quinate, and trigonelline), a tetrathionate reduction test, production of prodigiosin, and horse blood hemolysis was derived from a recent numerical taxonomic study (Grimont et al., J. Gen. Microbiol. 98:39-66, 1977). A total of 98.6% of 2,210 isolates from various sources could be assigned to 1 of 19 biotypes. Distribution and spread of 1,088 S. marcescens isolates throughout 13 clinical departments of Pellegrin Hospital (Bordeaux, France) were studied from 1968 through 1975. Except for one that colonized the intestinal tract of newborns, the six pigmented biotypes were seldom isolated. Each of the 13 nonpigmented biotypes showed a particular pattern of distribution and spread. The usefulness of S. marcescens biotyping was shown by relating several isolates recovered from patients and their inanimate environment and by pointing out the possible existence of infections or colonizations by two unrelated biotypes. S. marcescens strains isolated from the natural environment (water) are usually pigmented, and their biotypes are uncommon in hospitals. Biotyping can, therefore, be of help in epidemiological and ecological surveys.


Biotype determinations for monitoring of EK1 host strains used in recombinant DNA research. The biotypes of eight Escherichia coli K-12 strains were determined. Eight different biotypes were observed. Based upon the API biotype computer file, the appearance frequency for these K-12 biotypes ranged from 1/127 (infrequent) to 1/18,046 (rare).


Glucose intolerance in uremia. Quantification of pancreatic beta cell sensitivity to glucose and tissue sensitivity to insulin. The relative contributions of impaired insulin secretion and of tissue insensitivity to insulin to the carbohydrate intolerance of uremia were investigated in 10 chronically uremic subjects. Two types of glucose-clamp experiments were performed in each patient before and after 10 wk of thrice weekly hemodialysis. In both types the blood glucose concentration was maintained at a constant level by the periodic adjustment of a variable glucose infusion with a negative feedback formula.Hyperglycemic clamp. The blood glucose concentration was acutely raised and maintained 125 mg/dl above basal levels for 2 h. Since the glucose concentration was held constant, the glucose infusion rate is an index of glucose metabolism (M). After dialysis M increased in all patients from an average of 4.23 to 6.30 mg/kg body wt per min (P < 0.001). The plasma insulin responses (I) both pre- and postdialysis were biphasic with an early burst within the first 2-5 min, followed by a phase of gradually increasing insulin concentration. After dialysis the plasma insulin response diminished slightly. Consequently, the M/I ratio, an index of tissue sensitivity to endogenous insulin, increased postdialysis in all subjects by an average of 92% (P < 0.01). Euglycemic clamp. The plasma insulin concentration was acutely raised and maintained by a primecontinuous insulin infusion. The blood glucose concentration was held constant at the basal level by a variable glucose infusion as above. M/I again is a measure of tissue sensitivity to insulin (exogenous) and increased in all patients postdialysis by an average of 57% (P < 0.01). In two patients hepatic glucose production was measured with tritiated glucose during the euglycemic clamp and declined by 84% predialysis. A similar decrease (82%) was observed postdialysis. Thus, both the hyperglycemic and euglycemic clamp techniques demonstrated tissue insensitivity to insulin to be the dominant carbohydrate defect in uremia. The surprising apparent lack of consistency in the change in beta cell response postdialysis is explained by the strong inverse correlation between beta cell sensitivity to glucose and tissue sensitivity to insulin (r = -0.920; P < 0.001). Those individuals who showed the most striking improvement in tissue sensitivity to insulin actually decreased their serum insulin response to hyperglycemia; those whose improvement in tissue sensitivity was more modest showed increases in beta cell responses.


The roles of intracellular and extracellular Ca++ in glucose-stimulated biphasic insulin release by rat islets. Verapamil, an agent known rapidly to block calcium uptake into islets of Langerhans, has been used to study the roles of intra- and extracellular calcium in the two phases of glucose-induced insulin release. Rates of calcium uptake and insulin release during the first phase were measured simultaneously over 5 min in rat islets after maintenance in tissue culture for 2 days. Rates of (45)Ca(++) efflux and insulin release during the first and second phases were also measured simultaneously under perifusion conditions. For this, islets were loaded with (45)Ca(++) during the entire maintenance period to complete isotopic equilibrium. Under static incubation conditions 5 muM Verapamil had no effect upon Ca(++) uptake or insulin release in the presence of 2.8 mM glucose. By contrast, glucose-stimulated calcium influx was totally abolished without there being any significant effect upon first phase insulin release. Thus first phase insulin release is independent of increased uptake of extracellular calcium. The lack of effect of 5 muM Verapamil blockade on first phase insulin release was confirmed, under perifusion conditions, and was in marked contrast to the observed 55% inhibition of second phase release. (45)Ca(++) efflux was inhibited during both phases of the insulin release response. The results show that increased calcium uptake in response to glucose is not involved in the mechanism of first phase insulin release but is required for the full development and maintenance of the second phase release. It seems possible that intracellular calcium is the major regulatory control for first phase insulin release and that intracellular calcium and increased uptake of extracellular calcium contribute almost equally to the second phase of glucose-induced release.


Evaluation of the single radial haemolysis (SRH) technique for rubella antibody measurement. Sera from 1258 individuals have been tested by four laboratories for rubella antibody by both the haemagglutination-inhibition and single radial haemolysis techniques. There was good agreement between the results obtained by the two methods. Although sheep red blood cells were used in the single radial haemolysis plates, no problems were encountered with sera from patients with infectious mononucleosis. The single haemolysis technique was found to be simple, convenient, and reliable, and suited to the rapid screening of large numbers of sera to assess susceptibility to rubella in the context of a vaccination campaign. However, since the technique does not detect anti-rubella IgM, it should not be used as the only test to investigate suspected recent infection.


Tamm-Horsfall protein in the glomerular capsular space. Tamm-Horsfall protein was detected within the capsular space by immunofluorescence in 7 of 72 consecutive patients on whom renal immunopathological studies were performed. Three patients showed prominent aggregates or crescentic collections affecting 30-50% glomeruli; the remaining four patients showed smaller aggregates between lobules. All patients showed pathological evidence of tubulointerstitial disease. It is suggested that Tamm-Horsfall protein in the capsular space is a sign of intratubular urinary backflow and that Tamm-Horsfall antiserum is a useful addition to the reagents used in the immunofluorescence study of renal biopsies.


Lysosomal enzyme cytochemistry of blood neutrophils. Patients with bacterial infection may show altered membrane permeability of the primary azurophilic lysosomes of blood neutrophils. A new enzyme cytochemical technique, sensitive to increased membrane permeability caused by contact of neutrophils with acetone, saponin, low pH, Streptolysin O, bacteria, and nylon wool, has been developed. The method is of potential value as a screening test for bacterial infection and for detecting neutrophil damage during filtration leucopheresis.


Some considerations on the role of cementum in periodontal disease. The protective role of cementum against root resorption is discussed in relation to buried teeth, orthodontic treatment, replantation and periodontal disease. The essential feature seems to be a layer of partially calcified precementum or vital cementoblasts. Root resorption close to the epithelial attachment, although not common, is probably the result of death of cementoblasts caused by irritants from bacterial plaque, and the presence of severe of prolonged inflammation. Cementum exposed in the pocket can be affected in different ways by these irritants, and rendered unacceptable for re-attachment to periodontal tissue. Successful re-attachment procedures involve either the removal of the affected cementum or its treatment with agents partially to decalcify such as acids, or detoxify by phenol for example. Examples of treatment embodying some of these principles are illustrated by two case histories of localised gingival recession and one of intra-bony pocketing associated with an acute lateral periodontal abscess. In this case a follow-up radiograph taken 16 years later is presented as evidence of the permanence of repair which can be achieved. Root resorption which often follows the use of fresh autogenous bone from the ilium is then discussed and the conclusion reached that the vital cells in the transplant discourage the migration of cementoblasts from the adjacent periodontium. The cementum and dentine thus remain unprotected and susceptible to resorption.


Osseous repair in infrabony periodontal defects. The present investigation was undertaken to quantitate the osseous changes which occur throughout the entire circumferential extent of infrabony periodontal defects in patients with optimal plaque control. Fifteen defects were selected in nine patients. Periodontal surgery was scheduled after each patient had shown an ability to practice efficient plaque removal. Muco-periosteal flaps were raised and the osseous defects debrided. The dimensions of each defect were measured at several specific location points within the defect. The flaps were replaced at their original location and, post-operatively, optimal plaque control was maintained in the area (Mean Plaque Index 0.04). Six to 8 months after the initial surgery all areas were re-operated and the osseous defects were remeasured at the same specific location points. Each defect showed osseous regeneration at every location point. The mean initial osseous defect depth at a location point was 3.5 mm and the mean amount of bone regeneration which occurred was 2.5 mm. Crestal alveolar bone resorption occurred at almost half of the location points and averaged 0.7 mm. Eleven of the 15 defects had resolved completely. There were isolated areas where a shallow defect persisted in the remaining four defects. The behavior of an osseous defect throughout its circumferential extent was characterized by a combination of coronal bone regeneration (mean 77%) and marginal bone resorption (mean 18%). Infrabony periodontal defects may predictably remodel after surgical debridement and establishment of optimal plaque control.


Development of gingivitis in pre-school children and young adults. A comparative experimental study. Earlier studies suggest that children and adults differ in the propensity to develop gingivitis when oral hygiene is abandoned. To confirm the existence of such a difference, a comparative study of pre-school children and young adults was made with objective registration methods. The author performed all registrations. After a period of intensive oral hygiene, all cleaning of teeth was discontinued for 21 days. The amount of bacterial plaque, the amount of gingival exudate and crevicular leukocytes and the bleeding tendency were registered on days 0, 7, 14 and 21. During the experiment the amount of bacterial plaque increased continously in both groups. The amount of gingival exudate and the tendency to gingival bleeding increased to high values in the adults, while only a small rise was seen in the children. The amount of crevicular leukocytes increased in both groups, but the increment was greater in the adults. A comparison concerning differences in gingival exudate and bleeding tendency between pre-school children and adults was undertaken for gingival units that showed a similar plaque development. Under these statistically acceptable prerequisites, it was shown that there is a real difference in the tendency to develop gingivitis between pre-school children and adults.


Effect on plaque growth of xylitol and sucrose-containing chewing gums. Two experiments tested the effects of xylitol or sucrose-containing chewing gums on plaque formation. In the first experiment the 18 subjects maintained their normal dietary habits, and in the second they received a sucrose-free diet during the 3-day experimental periods. Plaque formation was assessed gravimetrically and/or planimetrically. When the dietary habits were not altered, neither the sucrose nor the xylitol-containing chewing gums had significant effects on the plaque scores. When sucrose was almost eliminated from the diet, plaque formation was significantly higher in the sucrose than in the xylitol and the placebo groups. Although plaque formation was lower in the xylitol group than in the placebo group, the differences were not statistically significant.


A comparison of the scalloped and linear incisions as used in the reverse bevel technique. Using a split-mouth technique in 20 patients, a comparison was made of the linear and scalloped incisions as used in the reverse bevel technique. Forty full thickness periodontal flap procedures were evaluated. The PlI and GI were recorded and gingival fluid collected at operation and at weeks 1, 2, 3, 4 and 12 after operation. Pocket depths and attachment levels were noted and gingival contour assessed, using the Contour Index, pre-operatively and 12 weeks after operation. Pain experience during the first week after operation was evaluated. No significant changes in PlI occurred throughout the study. The GI and gingival fluid flow showed comparable trends. More inflammation was present after the linear incision during the first 2 weeks after operation. Clinically, satisfactory results were achieved for both scalloped and linear incision procedures as shown by the improvement in gingival contour, reduction in pocket depth, slight gain in attachment, lack of gingivitis and low plaque scores.


Clinical assessment of periodontal dressings. Forty-one patients requiring gingivectomy in one or more areas were used for a clinical evaluation of three different periodontal dressings. Sixty-five operations were performed. Whenever possible different dressings were tested in the same patient. The type of dressing was chosen randomly, applied by one operator and left in place for 1 week. The patients were supplied with analgetic tablets. At day 7 the condition of the dressing was evaluated before removal. The patients' subjective experiences of pain, swelling, bleeding and fever, as well as use of pain relieving tablets, were recorded. The wound was evaluated with regard to the degree of epithelialization, presence of denuded bone and granulation tissue. The tendency to bleeding and the sensitivity of the teeth to a water spray (15 degrees C) were tested. At day 14 and 21 the same evaluation procedure was repeated. In addition the presence of plaque in the operated area was assessed. One of the dressings more frequently induced pain and swelling than the others. Tablet consumption was also higher when this dressing had been used. No statistically significant differences were found in the clinical assessment of wound healing, tendency to bleeding and the sensitivity of teeth.


Controlled clinical trial of sedative-anticholinergic drugs in patients with the irritable bowel syndrome. We studied 16 patients with long-standing irritable bowel syndrome of moderate severity using a controlled, double-blind crossover method. Five sedative-anticholinergic drug combinations and a placebo were tested. The subjective response was assessed with four subjective methods to include an increasing number of response variables. The patients preferred 30 mg phenobarbital plus 8 mg belladonna (P & B) to placebo (P = 0.02). Five of ten patients were helped "some" or "a lot" with placebo, while ten of 15 were helped "some" or "a lot" with P & B (P = 0.07). The ten prominent-symptoms method revealed that subjective symptoms such as nervousness, sleep difficulties, and tiredness were experienced as greater problems than diarrhea. The factor analysis method documented a strong placebo response. Simpler evaluation methods such as drug preference and a five-choice method appear more likely to show a positive drug effect, while the inclusion of a larger number of variables appears to emphasize the placebo portion of the response. These observations may help explain some of the apparent discrepancies between the conclusions of some controlled clinical trials and subsequent clinical experience.


Effect of nighttime anisotropine methyl bromide of duodenal ulcer healing and pain: a double-blind controlled trial. Anisotropine methyl bromide, an anticholinergic, 80 mg given orally at 8 P.M., suppresses gastric acid secretion through the night without significant side effects. Thirty patients with endoscopy-proved symptomatic duodenal ulcer disease completed a randomized, double-blind, placebo-controlled trial of nighttime anisotropine methyl bromide therapy. Eleven (69 per cent) of 16 anisotropine methyl bromide-treated and six (43 per cent) of 14 placebo-treated subjects healed their ulcers within two weeks of starting treatment. The anisotropine methyl bromide-treated subjects averaged 0.63 +/- 0.27 (mean +/- S.E.) episodes of nocturnal pain during the treatment period versus 2.71 +/- 1.08 episodes in the placebo group (P = 0.06). This is the first reported study of this type designed to evaluate the efficacy of an anticholinergic agent in the healing of duodenal ulcers. Although not conclusive, the results suggest nighttime anisotropine methyl bromide therapy may be useful in the treatment of duodenal ulcer disease. Further studies seem warranted.


Computed tomography in the diagnosis of Creutzfeldt-Jacob disease. Creutzfeldt-Jacob disease manifests clinically as a form of presenile dementia. It is now known to be caused by a transmissible agent, probably a "slow virus". Rapidly progressive atrophic changes on serial computed tomograms of the brain are highly suggestive of the disease. Neuroradiographic and pathological findings in two cases of Creutzfeldt-Jacob disease are documented.


Computed tomography in spinal dysraphism. The value of spinal computed tomography in the diagnosis and management of spinal dysraphism is described. Eight patients with diverse etiological agents were evaluated by clinical examination and subsequent computed tomography, without contrast enhancement. The diagnosis and location of the pathology thus ascertained allowed for appropriate surgery without invasive diagnostic studies. The value of this approach in children and in those patients in whom a low conus medullaris is suspected is obvious.


Simplified resazurin rennet test for diagnosis of mastitis. A simplified resazurin rennet test for diagnosis of bovine mastitis was devised. A tablet of resazurin and rennet was placed in a sterile test tube to which 10 ml of milk were added directly from a teat. The test tube was incubated for 1 h at 37 C. After incubation the change in color of resazurin and the time required for coagulation by the rennet were observed. From the results the milk samples tested were classified into four types. Cell count, modified California Mastitis Test, coagulase positive staphylococci, and contents of solids-not-fat, lactose, and protein differed among the four types. This method is simple and practically useful for diagnosis of bovine mastitis.


Milk secretion at the cellular level: a unique approach to the mechanism of exocytosis. Drugs which interfere with the mechanism of exocytosis such as colchicine and vincristine, so-called microtubule antagonists, are providing a fruitful approach to the study of milk secretion at the cellular level. Intramammary infusions of a milligram or less of these substances into lactating goats produce dramatic drops in milk yields in 24 to 36 h. These depressions are reversed substantially by 48 h. In vitro experiments and tissue observations confirm that these drugs are blocking secretion at the level of the lactating cell and that secretion of all the major milk components (fat globules, casein micelles, lactose, and water) is restrained. Mammary infusion of the plant lectin concanavalin A, a protein which binds to cell surface receptors, produces similar changes in milk flow to those of the microtubule antagonists. This indicates that cell surface membrane components perturbed by concanavalin also must be involved in the secretory mechanism. One of the known receptors for concanavalin A in the apical (secretory) plasma membrane of the lactating cell is the enzyme 5'nucleotidase. The possibility must be considered that this enzyme (glycoprotein), inactivated by concanavalin A, is involved in milk secretion.


The assessment of maladaptive parent-child interaction by direct observation: an analysis of methods. Six direct observation technologies for assessing parent-child interactions are examined: Descriptive-narrative, event recording, three types of interval sampling, and sequential event recording. Selected articles in the clinical literature are reviewed to illustrate use of each technology. Furthermore, the yield of each procedure in terms of four assessment criteria was evaluated: precise description of the parent-child interaction, target selection, identification of the intervention strategy, and evaluation of the intervention technique. The sequential-event-recording technology was determined to be most advantageous in terms of the four criteria.


Professional dietetic education in the U.S. Historical notes. Since its founding in 1917, The American Dietetic Association has been concerned with the development and improvement of educational programs for the professional dietitian. This article traces the evolution of professional dietetic educational programs from its beginning in the early cooking schools in the nineteenth century through the development of educational standards, the requirement for training beyond the bachelor's degree, and the establishment of academic requirements. The continued importance of educating the professional dietitian is evidenced by the inclusion of academic requirements as a prerequisite to membership in the Association.


Cyclandelate in the treatment of senility: a controlled study. Elderly patients often manifest a variety of symptoms (e.g., depression, memory loss, irritability, hostility), categorized as "senility" or "senile dementia," which are difficult to treat and represent a major therapeutic challenge to the geriatrician. This investigation was designed to assess, under double-blind conditions, a drug often prescribed for these symptoms--cyclandelate. In a 16-week study, 58 elderly patients were randomly assigned to two groups and received either 1600 mg of cyclandelate daily or identical-appearing placebo capsules. Initially, the every four weeks thereafter, the patients were examined for changes in vital signs and for adverse reactions, also, the Sandoz Clinical Assessment-Geriatric (SCAG) Scale and the Nurses Observation Scale Inpatient Evaluation (NOSIE) were completed. At the final evaluation, a physician's global rating was obtained. Our data suggest that cyclandelate is a safe and moderately effective treatment for certain symptoms of senescence in carefully selected patients.


Variations in state Medicaid programs.

Variations in state Medicaid programs. Many federal laws permit the states considerable latitude in determining the important characteristics of programs created under them. Yet, frequently, this aspect is overlooked in the analyses of differences in state-level programs. The purpose of this paper is to present a measure to aid in the analysis of one such program, Medicaid, and to illustrate some of the ways it can be useful. The Medicaid Program Index (MPI) differentiates among state Medicaid programs according to four important characteristics: inclusion of the medically indigent, the optional services covered, limitations on the provision of the basic services, and arrangements for paying providers. Data are presented to show that, in fact, the states do vary considerably on these factors, which can be analyzed in the aggregate (i.e., as the MPI) or separately. In addition, several uses for the MPI are discussed. They include: (1) identifying variations in state programs; (2) accounting for those differences by comparing them to promising explanatory variables; (3) identifying trends in program characteristics over time: and (4) developing hypotheses to account for those trends. Finally, it was suggested that similar measures can be developed to facilitate analyses of other federal/state programs.


Rhodamine immunohistofluorescence applied to plant tissue. Tissue slices from the roots and seeds of sanifoin (Onobrychis viciifolia, Scop.) exhibit bright autofluorescence when illuminated with blue (495 nm) light. This autofluorescence is indistinguishable from the fluorescence emission of fluorescein, the commonly used fluorochrome in immunohistochemical staining procedures. Rhodamine isothiocyanate, when coupled to immunoglobulin, and excited with green light at 546 nm, exhibits a reddish-orange fluorescence with an emission maximum at 590 nm. Plant tissue has little or no autofluorescence when illuminated at this wavelength and viewed with a 580 nm barrier filter. Therefore, use of rhodamine for immunohistochemical localization in plant tissue avoids interpretative complications due to inherent autofluorescence.


Identification of inbred strains of mice: II. Characterization of different substrains of the C3H strain. Substrains of inbred C3H mice differ significantly in their genetic constitution with respect to biochemical markers, skin grafting, and skeletal variations. The presence of such discrepancies among substrains poses a problem when comparing conclusions based on experiments done in different substrains. Therefore, methods of controlling the genetic constitution are necessary and important to avoid these discrepancies.


Loss of self-tolerance to single-stranded deoxyribonucleic acid (sDNA) in vitro. The spleens of many normal and autoimmune-susceptible strains of mice mount a specific, IgM, anti-sDNA plaque-forming cell (PFC) response in vitro in the absence of an exogenous source of antigen. This response was not related solely to levels of xenotropic or ecotropic virus and was generated from a small number of precursor cells capable of binding sDNA. Small numbers of anti-sDNA PFC were also apparent in serum-free medium and the response of low-responder strains could be augmented with pokeweed mitogen. T cells and macrophages were not essential and cell division was required early in culture to obtain a peak response on day 5. These results suggest that autoantigen-sensitive cells may escape normal regulatory mechanisms in vitro and differentiate into clones of autoantibody secreting cells.


Measurement of antigen-specific IgG autoantibody production in vitro. This report describes the development of a direct, highly sensitive and reproducible microassay for measuring picogram amounts of IgG antibody produced in spleen cultures of NZB/NZW female mice and specific for a well defined nucleic acid antigen (native ssRNA). The spontaneously synthesized antibodies were extensively purified from the culture supernatants. The isolated IgG anti-RNA antibodies had a high affinity, limited heterogeneity, and were specific for RNA as compared with DNA. Spleen cell cultures produced quantities of anti-RNA antibodies sufficient to account for a large proportion of the circulating anti-RNA antibodies in the whole animal. However, our results provide no evidence for the recently published suggestion (Sawada) et al., 1977. J. Immunol. 119:355) that autoreactive lymphocytes are released from normal immunoregulatory control during in vitro culture conditions.


Studies on the interaction between protein A and immunoglobulin G. I. Effect of protein A on the functional activity of IgG. Staphylococcal protein (A (PA) and IgG anti-Forssman immunoglobulin formed complexes that behaved functionally like IgM in their ability to lyse sheep erythrocytes (E) in the presence of whole guinea pig complement (GPC) and to fix purified guinea pig C1. Concanavalin A, a plant lectin that inhibited IgM but not IgG hemolytic activity, inhibited the hemolytic activity of IgG-protein A complexes that behaved like IgM but had no effect on complexes that behaved functionally like IgG. Since Con A is known to bind specifically to glucose and mannose residues, our results suggested that the interaction of protein A with the Fc region of IgG led to exposure of sugar moieties that may participate in complement (C) binding. The production of IgM-like complexes depended on the ratio of protein A to IgG and the empirical formula of these IgM-like complexes was found to be [(IgG)2PA]n. As the ratio of PA to IgG was increased, the resulting complexes tended to behave functionally like IgG but with reduced hemolytic activity and C1 fixing ability. Furthermore, the binding of C1 to EIgG was inhibited by PA and the binding of PA to EIgG was inhibited by C1 indicating that the binding sites for C1 and PA were located near each other or were identical. Our results offer a reasonable explanation for the reported effects of PA or mixtures of PA and IgG in vitro and in vivo.


Regulation of the autoimmune plaque-forming cell response to single-strand DNA (sDNA) in vitro. We have shown that young autoimmune and normal strain mice possess autoantigen-sensitive cells potentially capable of producing anti-sDNA autoantibody in the absence of normal regulatory mechanisms in vitro. In certain strains such as B/W mice, these regulatory mechanisms presumably break down with increasing age, and autoimmunity develops. These regulatory mechanisms might consist of sDNA, T cells, or some combination of these since both of these agents suppressed the anti-sDNA PFC response in vitro. The sDNA may have inhibited PFC development by a receptor blockade mechanism since i) spleen cells pulsed with sDNA for short periods and then washed were suppressed after 5 days of culture; ii) treatment of these blocked cells with trypsin and DNase I restored the anti-sDNA response; iii) the PFC remaining in partially blocked cultures were of lower avidity than PFC in unblocked cultures; and iv) the target of sDNA may be a B cell. Thymocytes and splenic T cells suppressed the anti-sDNA response but not the anti-SRBC response in vitro in a dose-dependent manner. The suppressive capacity of thymus cells did not decline with age in B/W mice. In addition, thymus cells activated by competing foreign antigens could also suppress the anti-sDNA response. The relationship between these modes of regulating autoreactivity remains to be investigated.


Inhibition enzyme immunoassay, application to human apolipoprotein B. Inhibition enzyme immunoassay was applied to human apolipoprotein B (apo-B) from plasma. The technical conditions of the assay were determined. The detection limits of the assay were 200 ng to 10 microgram/ml. Correlation coefficients obtained between enzymoassay and rocket immunoelectrophoresis on one hand and radial immunodiffusion on the other were respectively 0.84 and 0.80. The inhibition enzymoassay provides a specific and highly sensitive method for the quantitation of apo-B.


Use of ELISA for measuring immunoconglutinins. An enzyme-linked immunosorbent assay (ELISA) for detection of immunoconglutinins (IKs) has been developed. IKs are allowed to bind to solid-phase C3 and are then assayed using alkaline phosphatase coupled to anti-IgG or anti-IgM. IK activity was detected in some patients' sera up to 50,000-fold dilution. Significant correlation (r = 0.65) was obtained between the levels of IgM-IKs measured by ELISA and by conventional hemagglutination assay, IgG-IKs and hemagglutination titers did not correlate (r = -0.15).


DNA antibodies detected by microhemagglutination test in the diagnosis of systemic lupus erythematosus. A method of tanned erythrocyte agglutination of wide applicability is described for the study of DNA antibodies. The practical aspects of the method have been explored in estimation of antibodies to DNA in human cases of systemic lupus erythematosus, discoid lupus erythematosus, rheumatoid arthritis, other collagenoses and not related diseases. This method was found to be of high sensitivity and specificity, detecting DNA antibodies only in sera of systemic lupus erythematosus. Results were compared with those obtained by immunofluorescence test using rat liver hepatocytes as source of nuclei.


Primary reconstruction of the mandible with a wire mesh prosthesis. A stainless steel wire mesh prosthesis was used as a primary mandibular replacement in 102 patients following resection of malignant neoplasms arising in the head and neck. In 67 patients the prosthesis was considered successful. Failure of the host to tolerate the prostheses was associated with history of previous irradiation, extensive resections, and the loss of distant skin flaps used for coverage of the prosthesis. But the prosthesis is tolerated by the host in 90% of the cases if it is inserted in a non-irradiated bed, covered with local tissues, and the resection is limited to the maxillo-oral complex only.


Unspecific cellular immunity before therapy in patients with squamous cell carcinoma of head and neck. An introduction to the role of lymphocytes in immunological reactions is given. Two fundamental categories of immunological response are described which are mediated by two distinct subpopulations of lymphocytes: B-lymphocytes are responsible for humoral immune reactions and T-lymphocytes are involved in cell-mediated immunity. Information is given on the role of the immune system in generation of anti-tumour activities and of mechanisms leading to an acceleration of tumour growth. Several pathways of cytotoxic and blocking reactions against target cells are mentioned. Furthermore, methods are described for monitoring the non-specific immune reactivity of the host. These nonspecific cellular immune responses in 30 patients with squamous cell carcinoma of the head and neck were compared with those in 30 healthy controls. Assays were performed in vitro to evaluate the blastogenic response of lymphocytes to the mitogens PHA (phytohaemagglutinin) and PWM (pokeweed mitogen) and to quantify T-rosetteforming lymphocytes in the peripheral blood. The in vivo assays used were the delayed cutaneous hypersensitivity reaction to the primary stimulus of DNCB (dinitro-chloro-benzene) and the recall reaction to PPD (purified protein derivate). The carcinoma patients demonstrated significant impairment of lymphocyte blastogenesis reactions to PHA but not to PWM. The percentage and absolute counts of T-rosettes was significantly reduced in cancer patients compared with normal controls. Skin test reactivity to de-novo sensitation with DNCB was significantly abnormal in patients with head and neck cancer. However, delayed type hypersensitivity evaluated with PPD (recall antigen) was not significantly reduced. After subdividing the cancer patients according to their clinical stage of disease and subsequent analysis, they showed no correlation between clinical stage and immune reactivity. These data indicate that PHA induced lymphocyte blastogenesis, enumeration of T-rosette levels and evaluation of delayed hypersensitivity reaction to DNCB are potentially useful for the study of squamous cell carcinoma of head and neck to monitor effects of tumour treatment and perhaps to evaluate a correlation between immunocompetence and prognosis.


The effects of "BAR" therapy on oral malignant tumors. "BAR" therapy is a combined therapy with BUdR (Radiosensitizer), Antimetabolites (5-FU, FT-207 etc.) and Radiation for malignant tumours. How radiation can be reduced as far as possible and how the effects of treatment can be increased as much as possible are the objectives of this study of combining radiation and BUdR therapy. The authors attempted to irradiate 3-5 days after the BUdR and antimetabolite had been infused via the superficial temporal artery, in 12 malignant oral tumours (11 squamous cell carcinomas and 1 reticulum-cell sarcoma). BUdR 50-250 mg/day, antimetabolites (5-FU) 10-250 mg/day and a total irradiation dose of 6000 rads by 6 MeV Linac X-ray or Co-60 gamma ray, 200 rads/day were given. 9 marked responses, 2 moderate responses and 1 no response (2 cases were operated on by local resection) were obtained by the authors. Side effects of treatment were observed during the course of "BAR" therapy. Stomatitis was found in all patients and it occurred on the mucosa of the tumour-affected site especially. Dermatitis of the skin of the face was noted in 6 cases, resembling irradiation dermatitis. Fever was observed in 4 cases and it always occurred after irradiation. Diarrhoea was noted in 3 cases and occurred before irradiation, 2 out of 3 were given BUdR 0.1 g and the remaining one was given BUdR 1 g, and 5-FU lg. In addition, there were: 1 loss of appetite, 1 nausea and 1 exfoliation of nails.


In vitro development of inner cell masses isolated immunosurgically from mouse blastocysts. II. Inner cell masses from 3.5- to 4.0-day p.c. blastocysts. This paper describes the development in culture of inner cell masses isolated immunosurgically from C3H/He mouse blastocysts immediately after collection between 3.5 and 4.0 days p.c. By 24--48 h most of the inner cell masses isolated from half-expanded blastocysts, and about 50% of those from expanded blastocysts, regenerate an outer layer of trophectoderm-like cells and so resemble mini-blastocysts. With further in vitro culture these structures attach to the substratum and give rise to trophoblast-like giant cells, together with clusters of parietal endoderm cells or inner cell masses surrounded by visceral endoderm. Many of the inner cell masses from the remaining expanded blastocysts develop into floating structures with an outer layer of endoderm cells, and by 7 days consist of a large fluid filled cyst surrounding a collapsed vesicle of epithelial cells. Mesodermal cells line the cysts and form numerous blood islands. When mechanically disrupted, and grown as attached sheets of cells, these cystic structures give rise to patches of trophoblast-like giant cells similar to those described in the previous paper. These results suggest that the inner cell mass of normal mouse blastocysts contains cells which are capable of giving rise to trophoblast in culture.


Isolation and development of the inner cell mass after exposure of mouse embryos to calcium ionophore A23187. Compacted morulae and blastocysts were obtained from CBA, BALB/c and CFLP strains of mice. The embryos were incubated in medium containing 2 X 10(-5) M or 2 X 10(-6) M ionophore A23187. With 2 X 10(-6) M ionophore, morulae survived for up to 12 h showing slight decompaction. Normal development resumed when the morulae were explanted to fresh medium. There was no detectable effect on blastocysts. With 2 X 10(-5) M ionophore, morulae survived for about 20 min and then extensive cell death occurred after this time. With blastocysts however, selective lysis of trophectoderm cells occurred after approximately 30 min following their swelling and vesiculation but the inner cell mass cells (ICM) remained apparently intact and viable. Nearly 80% of the early blastocysts obtained 87 h post-ovulation and all of the late blastocysts used after 12 h in culture (99 h blastocysts) showed this response. Individual fluid accumulating cells were detected in a few isolated ICMs after their overnight culture in vitro, especially in those obtained from early blastocysts, but the majority of the ICMs did not have these cells. All aggregates of three to five ICMs, except one which reformed into a blastocyst, developed as embryoid bodies after 2 days in culture and these survived for up to 10 days; in some cases they developed into cystic embryoid bodies or attached to the culture dish displaying a variety of cell types. The development of the isolated ICMs in vivo was judged to be normal after their transfer to intact host blastocysts as these developed as chimaeric embryos to term.


Cell division, cell elongation and the co-ordination of crystallin gene expression during lens morphogenesis in the rat. A quantitative analysis of cell division and cell elongation was carried out during lens morphogenesis in the rat. At 13 days of development elongating cells in the posterior part of the lens vesicle (presumptive fibre cells) have a lower mitotic activity than cells in the anterior vesicle. By 14 days these elongating cells do not divide. Thus at 14 days of development the lens can be separated into two compartments; a proliferation compartment in the anterior lens and an elongation compartment in the posterior lens. The three main groups of lens-specific proteins, alpha-, beta- and gamma-crystallins, were localized by immunofluorescence. alpha-crystallin is the first crystallin to be detected and is localized in some lens pit cells at 12 days of development. By 14 days all lens cells contain alpha-crystallin. beta- and gamma-crystallins are detected later at 12 1/2 days and are localized in some cells situated primarily in the posterior part of the lens vesicle. At later stages of development these crystallins are restricted to cells of the elongation compartment, i.e. presumptive fibre and fibre cells. Possible mechanisms that govern the temporal and spatial distribution of crystallins are discussed.


Time of commitment of inside cells isolated from preimplantation mouse embryos. Groups of inside cells (ICs) and inner cell masses (ICMs) were isolated from individual mouse embryos between the late morula and 3 1/2-day expanded blastocyst stages using a modified immunosurgical procedure, and their purity and developmental potential were assessed in vitro. Several different techniques failed to detect the presence of viable contaminating outside cells on ICs isolated from any of the stages studied. The numbers of inside cells isolated from the earlier stages, counted in air-dried preparations, were considerably higher than previous estimates from serial sections; whereas the numbers isolated from expanded blastocysts were in reasonable agreement. Thus the proportion of inside cells recovered by immunosurgery decreases over this period of development. In view of the evidence that inside cells divide at a faster rate than outside cells at these stages, it is argued that there may be an outward movement of inside cells capable of forming trophectoderm, during expansion of the blastocyst. ICs and ICMs in vitro were observed to develop in one of two distinct ways according to the stage at which they were isolated. ICs from late morulae and some early cavitating blastocysts formed blastocyst-like vesicles over a period of 24--36 h in culture. The presence of trophectoderm cells in these vesicles was confirmed by the persistence of giant cells after ectopic transfer. In contrast ICs from a minority of early cavitating blastocysts, and all ICMs from 3 1/2-day expanded blastocysts did not form vesicles, but proliferated endoderm-like cells. Thus at least some inside cells do not appear to lose the capacity to form trophectoderm and do not become committed to an ICM fate until after the initial formation of the blastocoel cavity.


In vitro development of inner cell masses isolated immunosurgically from mouse blastocysts. I. Inner cell masses from 3.5-day p.c. blastocysts incubated for 24 h before immunosurgery. This paper describes the in vitro development of inner cell masses isolated immunosurgically from mouse blastocysts which had been collected on 3.5 days p.c. and then incubated for 24 h. The inner cell masses continue to grow in culture and develop through a series of stages with increasing complexity of internal organization. By day 1 all of the cultured ICMs have an outer layer of endoderm, and by day 3 some of them have two distinct kinds of inside cells; a columnar epithelial layer and a thin hemisphere of elongated cells. Later, mesodermal cells appear to delaminate from a limited region of the columnar layer, close to where it forms a junction with the thinner cells. By day 5, about 25% of the cultured ICMs have a striking resemblance to normal 7.5-day p.c. C3H embryos, with embryonic ectoderm, extra-embryonic ectoderm and chorion, embryonic and extra-embryonic mesoderm, and visceral endoderm. When mechanically disrupted and grown as attached clumps of cells in a tissue dish, these embryo-like structures give rise to trophoblast-like giant cells. These results suggest that the inner cell mass of 4.5-day p.c. blastocysts contains cells which can give rise to trophoblast derivates in culture.


Trypanosoma cruzi: in vitro induction of macrophage microbicidal activity. Normal, resident and inflammatory mouse peritoneal macrophages can be induced to display microbicidal activity against trypomastigotes of Trypanosoma cruzi by exposure to products from antigen-pulsed, sensitized spleen cell populations. Optimal macrophage microbicidal activity was achieved by constant exposure and daily renewal of the spleen cell factors. Macrophages obtained after an intraperitoneal injection of mild inflammatory agents were rapidly induced, displaying trypanocidal activity 24 h after exposure to the active spleen cell factor(s), and by 48 h, parasites were no longer observed. Resident peritoneal macrophages required 24 h longer for activation. Removal of the factor(s) before achieving complete disappearance of intracellular parasites led to resumed growth of the surviving organisms. The spleen cell factor(s) is effective when added either before or after exposure of the macrophages to trypomastigotes, and does not itself alter parasite viability. Dilution of the factor(s) up to 1:16 still results in significant trypanocidal activity. In vivo activated cells, obtained after a specific secondary challenge of animals infected with T. cruzi or Bacille Calmette-Guérin, lose their trypanocidal activity under in vitro conditions. This loss of activity can be prevented or restored by the addition of the active spleen cell factor(s). Induction of trypanocidal activity is also obtained with products from Concanavalin A- or lipopolysaccharide-stimulated normal spleen cells.


Resistance of neoplasms to immunological destruction: role of a macrophage chemotaxis inhibitor. Several tissue culture lines of 6C3HED, a murine lymphoma, were more susceptible to immunologic destruction in vivo than the highly virulent 6C3HED line maintained by serial intramuscular transplantation. The attenuated tissue culture cells were rejected by normal syngeneic recipients, but thymectomized mice were unable to reject attenuated cells. In such mice, the growth rate of attenuated cells was equivalent to the growth rate of virulent cells in normal syngeneic mice. The increased susceptibility of attenuated cells to destruction by syngeneic hosts was shown to correlate with decreased production by the tumor cells of a macrophage chemotaxis inhibitor, and not with altered antigen density. In addition, when inhibitor isolated from virulent cells was administered to mice challenged with attenuated cells, the latter cells became virulent in vivo. When attenuated and virulent cells were administered simultaneously in the same host, the attenuated cells were able to develop into progressively growing tumors. The data suggest that the successful growth of neoplastic cells in normal may require tumor cells to produce factors which subvert the ability of the host to mobilize macrophages rapidly at the tumor site.


[Determination of digoxin in serum. Comparison of radioimmunoassay and a heterogeneous enzyme immunoassay (author's transl)]. This paper describes the evaluation of a heterogeneous enzymeimmunoassay (EIA, subtype ELISA) for the determination of digoxin in serum. Results are compared with those obtained from a radioimmunoassay (New England Nuclear, 125I-Digoxin). The limit of detection is 0.3 microgram/1 (0.4 nmol/1). The range of the test is from 0.3 unto 5.0 microgram/1 (0.4--6.4 nmol/1). Within-batch precision ranged from 7 to 11%, between-batch precision from 8--14%. Pure digoxin, added to solutions of albumin and pooled sera, gave recoveries between 87 and 106%. 116 sera from patients taking digoxin exclusively yielded no systematic difference compared to the results of a radioimmunoassay (RIA) (equation of the bivariate regression CELISA = 0.954 . CRIA + 0.14 (microgram/1) (0.18 nmol/1). Nevertheless marked differences between both tests were observed in individual cases. Digitoxin yielded in vitro and in vivo a cross-reactivity of 7 to 14% depending upon the concentration. In 68 sera from patients, taking digoxin plus spironolactone, we found results that were on average 0.48 microgram/1 (0.64 nmol/1) higher with the ELISA than with the RIA (p less than 0.01%). With respect to practicability the ELISA test for digoxin is very similar to the analogous RIA both using the solid phase technique.


Actin in mammalian sperm heads.

Actin in mammalian sperm heads. An actin-like substance has been detected in the postacrosomal region of mammalian spermatozoa by indirect immunofluorescence. The antigen was localized using an anti-actin antiserum from a patient with active chronic hepatitis. The actin-like contractile proteins may be important in sperm function and spermegg interactions during fertilization.


Isoelectric focusing studies on the beta-fructofuranosidases and alpha-glucosidases of Streptococcus mitis. Extracts of Streptococcus mitis ATCC 903 were analysed for beta-fructofuranosidase and alpha-glucosidase activities by isoelectric focusing in thin-layer polyacrylamide gels combined with zymogram procedures. Three bands of activity were visualized in the gels after incubation with sucrose (pI 4.05, 4.25 and 4.85) and three other bands after incubation with p-nitrophenyl alpha-D-glucopyranoside (pI 3.90, 4.45 and 4.65). The enzymes responsible for the reaction with sucrose were identified as beta-fructofuranosidases (EC 3.2.1.26) for the following reasons: identical enzyme bands were visualized in the gels after incubation with raffinose; no enzyme bands appeared in the gel after incubation with the alpha-glucosides maltose, turanose, trehalose and melezitose; and the soluble fraction hydrolysed sucrose to equimolar amounts of glucose and fructose.


The coating of respiratory syncytial (RS) virus-infected cells in the respiratory tract by immunoglobulins. During the course of 26 respiratory syncytial (RS) virus infections, infected cells in the respiratory tract become coated with immunoglobulins (IgA, IgG, and IgM), IgA being predominant. Methods are described for detecting both intracellular virus and coating immunoglobulin using a double staining technique and immunofluorescence. IgA coating antibody appears in small amounts very early in the illness. The relationship of coating antibody to pathogenesis, prevention, and recovery from RS virus infection is discussed.


Cerebral aspergillosis following intracranial surgery. Case report. The authors report a case of cerebral aspergillosis. This is only the fifth case following intracranial surgery noted in the literature. Pathogenesis, angiographic findings, and results of cerebrospinal fluid culture are discussed.


Developmental changes in the sucrase-isomaltase complex in rat intestinal mucosa. Developmental changes in sucaras-isomaltase complex formation were investigated in intestinal mucosal homogenates and brush border membranes of 15-day-old, 18-day-old and adult rats using Sephadex G-200 column chromatography and polyacrylamide disc gel electrophoresis. Disaccharidases were solubilized by papain treatment. The molecular weight of the complex did not change during development, however, the activity ratio of sucrase to isomaltase increased during development. Furthermore, a significant amount of free isomaltase, which was probably not to be derived from intestinal brush border membrane, was detected before the weanling.


How the industrial physician can reduce mortality from asbestos-related diseases. Risk indicators for asbestos-related diseases (cancers of the lung, larynx, and alimentary tract; mesothelioma; and asbestosis) and methods of early detection are reviewed and evaluated. The best medical means of reducing mortality from these diseases is to recognize particularly susceptible persons during a preemployment examination and to recommend that they not be hired for jobs involving asbestos exposure. Workers necessarily exposed to asbestos should be enrolled in a medical screening program and urged not to smoke.


Transplantation of cadaver kidneys from anencephalic donors. Of 14 potential anencephalic donors, the kidneys of six were transplanted to recipients ranging in age from 4 to 19 years and in weight from 8 to 49 kg. In three recipients, serum creatinine levels are less than 1.0 mg/dl 1.5 to 9.5 years after transplant. The transplants failed in two for technical reasons; in one, the kidneys were lost by rejection. The other anencephalic infants were not suitable as donors because of rapid deterioration of vital signs (4), ABO incompatibility (3), and inability to perfuse the kidney (1). Successfully transplanted kidneys from this source rapidly increase in size and function to accomodate even large recipients.


Intermittent bag ventilation of preterm infants on continuous positive airway pressure: The effect on transcutaneous PO2. Preterm infants with respiratory distress syndrome requiring continuous positive airway pressure are frequently assisted with intermittent bag ventilation. We assessed the effect of intermittent bag ventilation on PO2 in these infants by continuous monitoring with a transcutaneous oxygen electrode. The behavior of the infants during bagging determined the effect on PO2. Bag ventilation decreased PO2 significantly (P less than 0.01) in infants who were restless during bagging, whereas a significant increase in PO2 (P less than 0.02) was observed in infants who were quiet while being bagged. Although the duration of the increase in PO2 was variable, a sustained rise (greater than 20 minute) occurred in almost half of the infants studied. Intermittent bag ventilation appears to be beneficial in infants who remain quiet during the bagging period.


Bacterial colonization of neonates admitted to an intensive care environment. In order to elucidate some of the factors responsible for the high rate of nosocomial infection associated with neonatal intensive care, we studied bacterial colonization in 63 infants admitted to a neonatal intensive care unit. In a six-month period, cultures of nose, throat, umbilicus, and stool were obtained on admission and every three days from all infants staying in the NICU greater than or equal to 3 days. Study infants did not develop "normal" aerobic flora. Forty-eight percent of infants grew Escherichia coli from stool, but 52% had stool colonization with Klebsiella, Enterobacter, or Citrobacter, the only other Enterobacteriaceae encountered. KEC were also isolated from throat, nose, and umbilicus in 22%, 22%, and 24% of patients, respectively. The risk of stool colonization with KEC increased with duration of hospitalization: 2% of infants were colonized on admission, 60% after 15 days, and 91% after 30 days. Stool colonization with E. coli seemed to protect infants from colonization with other gram-negative bacilli. Thirteen of 20 infants, however, developed pharyngeal GNB colonization in spite of pre-existing abundant growth of alpha streptococci. Antibiotic therapy for greater than 3 days was associated with the isolation of KEC in stool and GNB in the throat, but birth weight less than 2,500 gm and lack of breast milk feedings were not.


Hemodynamics of congenital diaphragmatic hernia in lambs. Despite surgical treatment, congenital foramen of Bochdalek diaphragmatic hernia continues to carry a high mortality rate due to associated respiratory insufficiency. We studied the pathologic and hemodynamic changes that result from this condition in lambs. Surgical creation of diaphragmatic hernias in fetal lambs was performed in utero with subsequent delivery by cesarean section near term. Cardiac catheterization was performed on these newborn lambs immediately after delivery, before and after surgical repair of the defect. Data from five of these lambs were compared to data obtained from seven normal lambs. Pulmonary hypertension was found only in lambs with hernias. Pulmonary artery pressures and the mean ratio of pulmonary to systemic resistance were higher in experimental lambs. Oxygen saturation and average cardiac index were higher in normals. Lambs in the experimental group, but not in the control group, had large left-to-right shunts at the level of the ductus arteriosus in the early neonatal period. Arterial oxygen saturations were consistently low with no differences in pre- and post-ductal samples, which suggests right-to-left shunting at the atrial level or physiologic shunting across the unexpanded lungs. No further expansion of the hypoplastic lungs occurred following decompression by surgical hernia repair, but transient hemodynamic improvement was noted in some cases. Surgical ligation of the ductus arteriosus did not significantly alter the clinical condition of the lambs. Lungs in lambs with hernias were grossly abnormal, the left appearing more hypoplastic than the right.


Repair potential in periodontal disease: the interproximal channel. Interproximal channeling defects associated with lingual denudation of the root are often encountered in patients with insidiously progressive chronic periodontitis. Several cases of such lesions are described and their  potential for repair demonstrated. It is suggested that this type of defect is predictably amenable to successful therapy by exposure and curettage, and that restoration of lost periodontal structures can be anticipated within the interproximal portion of the lesion.


Effects of a mouthwash in an irrigating device on accumulation and maturation of dental plaque. A study was conducted to determine whether there was any advantage in using a commercial mouthwash over water in a pulsating oral irrigating device on dental plaque growth and maturation. The amount of plaque accmulated on the test teeth of human subjects was measured on days 1,3,5,7 and 10 during the experimental period by using the two-tone disclosing dye solution and the Quigley and Hein scoring method. The results showed the value of using the two-tone disclosing dye in visualizing the growth and maturation of bacterial plaque in situ. There was a marked delay in the rate of plaque maturation by the commerical mouthwash delivered by an irrigating device. There were no statistical differences in plaque accumulation between the control and treatment groups for the 10-days test periods.


A comparison of postsurgical healing following debridement by ultrasonic or hand instruments. Subjects for the study were 15 patients requiring periodontal surgery in the maxillary posterior quadrants. A split mouth technique with assignment of quadrants by random alternation was used. Assessments were carried out at given time intervals using the Gingival Index, crevicular fluid measurement, Plaque Index and Retention Index. Pain experience following surgery was also noted. Approximately 8 weeks after the initial assessment, periodontal flap surgery was carried out. On the one side debridement was carried out using an ultrasonic scaler, on the other side, hand instrumentation only was used. On the side receiving ultrasonic debridement during surgery, there was an increased rate of healing as measured by the Gingival Index and crevicular fluid. There was no difference in postoperative pain experience, Plaque Index or Retention Index.


Omission of pepsin from simulated gastric fluid in evaluating activated charcoals as antidotes. Although simulated gastric fluid USP calls for 3.2 g of pepsin/liter, most researchers omit pepsin when evaluating adsorbents. The present results show that, although pepsin adsorbs strongly to activated charcoal, it does not interfere significantly with the adsorption of a typical drug like sodium salicylate. Therefore, its omission is justified. Gastric mucin also had almost no effect on salicylate adsorption.


Cyclic changes in potential and resistance of the beta-cell membrane induced by glucose in islets of Langerhans from mouse. 1. The effects of KCl on the membrane potential were studied in cells from mouse islets of Langerhans identified as beta-cells by the characteristic pattern of electrical activity induced by 11.1 mM glucose. 2. In the absence of glucose, when the beta-cell membrane does not exhibit electrical activity, the dependence of the membrane potential upon external potassium [K+]o, could be described by the constant field equation using a PK/PNa ratio between 30 and 75. 3. In 11.1 mM glucose, when the beta-cell membrane potential fluctuates between a silent phase at about -50 mV and an active phase at about -40 mV giving rise to a train of spikes, the dependence of the membrane potential upon [K+]o could also be described with the constant field equation using a smaller PK/PNa of about 15, during the silent phase, and of about 8, during the active phase (foot of the spikes during the burst). 4. A bridge amplifier for measuring the changes in membrane potential during the application of pulses of current through the same micro-electrode was used to estimate the input resistance of a beta-cell. In 11.1 mM glucose, rough estimates of the membrane resistance during the silent phase averaged 1.2 X 10(8) omega. 5. The time course of the changes in input resistance of the cell when switching from 0 to 11.1 mM glucose showed a transient decrease from 0.9 X 10(8) to 0.7 X 10(8) omega followed by an increase to 1.2 X 10(8) omega. 6. The burst pattern was shown to result from the superposition of two potential changes: (a) 5--10 mV depolarization (lasting about 10 sec in 11.1 mM glucose), and (b) 10--50 mM spikes (lasting about 0.1 sec). Only the latter could be suppressed by hyperpolarizing current injection. 7. Application of pulses of current during the various phases of the electrical activity in 11.1 mM glucose enable us to compare the resistance during the silent and active phases. This was found to be oscillating between a high resistance value at about 1.2 X 10(8) omega before each burst and a low resistance value at 0.9 X 10(8) omega during the active phase at the foot of the spikes. In some cells the resistance during the silent phase remained fairly constant. In other cells it increased gradually from 1.1 X 10(8) to 1.3 X 10(8) omega measured just before each burst of spikes. 8. The observed increase in resistance induced by glucose together with the measured dependency of the membrane potential on [K+]o with and without glucose can be explained by postulating that in the presence of glucose the K+ permeability of the beta-cell membrane is reduced. 9. The oscillations between a high and a low resistance state in the presence of 11.1 mM glucose could be due to a sudden decrease in K+  permeability followed by a much larger increase in permeability to other ions, presumably Na+ and Ca2+.


Influence of external potassium concentration on secretory responses to cholecystokinin-pancreozymin and ionophore A23187 in the pancreatic acinar cell. 1. The inhibitory effect of a diminution in [K+]o on the secretory processes of the pancreatic acinar cell was analysed in the isolated and perfused rat pancreas. 2. Partial replacement of KCl with NaCl produced falls in both amylase output and pancreatic juice flow which were induced by 5 m-u. cholecystokinin-pancreozymin (CCK-PZ)/ml., and the responses were slowly regained after reintroduction of a standard concentration of KCl. 3. A quantitative relation was found between the amount of amylase released by CCK-PZ and [K+]o over the range 1.0--5.6 mM. A linear relation was obtained between the ratio of E1K+]3(0)/amylase output and [K+]3(0). 4. A quantitative relation was also found between the pancreatic juice flow induced by CCK-PZ and [K+]o over the range 1.0--5.6 mM. A linear relation was obtained between the ratio of [K+]3(0)/juice flow and [K+]3(0). 5. The results obtained may be explained by a model as follows: (1) amylase output and juice flow induced by CCK-PZ are simply proportional to the amount of complex composed of a carrier molecule bearing one Ca and four Na atoms, (2) the inward movement of the complex is tightly linked to the CCK-PZ-induced activation of pumps which are postulated on both basal and apical sides of the membrane of the acinar cell, and (3) the Na:K coupling ratio of the pumps is close to 3:2. 6. A quantitative relation was also found between the amount of amylase released by Ca reintroduction after pre-treatment with Ca-ionophore A23187 and [K+]o. This may be explained by a model essentially similar to that mentioned above. 7. Total replacement of NaCl with NaBr slightly reduced the CCK-PZ-induced fluid and amylase secretion. Total replacement of NaCl with sodium isethionate or with sodium pyruvate, however, virtually abolished the CCK-PZ-induced fluid and amylase secretion.


Exogenous prostaglandins and gastric secretion in the cat. 1. In the conscious gastric fistula cate PGE2 was shown to produce dose-related inhibition of gastric acid and pepsin secreted in response to pentagastrin, histamine and insulin. 2. PGF2alpha had little effect on pentagastrin-stimulated gastric acid and pepsin secretion. 3PGF2 delayed the tachyphylaxis of gastric acid stimulated by pentagastrin and histamine, but not that stimulated by insulin. 4. Although not delaying tachyphylaxis of insulin stimulated acid, PGE2 delayed tachyphylaxis of insulin stimulated pepsin.


Endogenous prostaglandins and gastric secretion in the cat. 1. The gastric juice outputs of acid, pepsin, PGE and PGF, and the plasma concentrations of PGE and PGF have been measured in response to I.V. infusions of pentagastrin, histamine and insulin in the conscious cat. 2. There were significant correlations between the output of gastric acid and gastric outputs of both PGE and PGF during secretion produced by all stimulants. Furthermore, there were similar significant correlations between the gastric outputs of pepsin and both PGE and PGF. However, during insulin stimulation there was significantly more pepsin output per unit PGE or PGF output than during either pentagastrin or histamine stimulation. 3. The correlations between the outputs of gastric acid and both PGE and PGF were similar during pentagastrin and insulin stimulation whereas those between acid and PGE and PGF altered during the infusion of histamine. 4. It is concluded that these data partially, but not entirely, support the hypothesis that local release of prostaglandins may act as a negative feed-back mechanism on gastric acid secretion. 5. Plasma prostaglandin concentration did not correlate with changes in acid or pepsin secretion.


The physiological properties of amine-containing neurones in the lobster nervous system. 1. Our previous studies have shown that octopamine and serotonin are found associated with a system of neurones in the connective tissue sheath of the second roots of lobster thoracic ganglia. To try to understand the mechanism of activation of these neurones, we undertook an examination of their general physiological properties. 2. All of the neurones receive excitatory synaptic input that has a cholinergic pharmacology, which suggests that it may be from sensory neurones. A very limited number of cells, possibly one, provdes the total synaptic input to all the cells in the roots of the second and third thoracic segments. 3. The cells within one root are electronically coupled to each other. The extent of coupling varies widely between cells; on occasion the coupling is sufficiently tight for action potentials originating in one cell to trigger action potentials in the neighbouring cell. 4. The majority of the cells show no spontaneous activity at temperatures below 14 degrees C, but become spontaneously active above that temperature. Cells cycle reversibly from silent to continuously active to bursting and back as the temperature is increased and decreased. 5. Octopamine and serotonin both inhibit the bursting activity. The octopamine response is blocked by phentolamine but not by propranolol, while the inhibitory action of serotonin is unaffected by either of these drugs. The amine-inhibition of the firing could be an autoregulatory mechanism for cell activity. 6. The physiological properties described in this paper suggest that the widely dispersed amine-containing neurones in lobsters behave like a neurosecretory organ in terms of their mechanism of activation.


Dimensional and occlusal changes in fluid resin dentures. This study evaluated complete dentures processed with fluid acrylic resins. The dentures were constructed with the aid of a new flask and modified spruing procedures, with the teeth immobilized in the hydrocolloid mold, and with slight mechanical vibration provided during the pouring of the resin. The fluid resin dentures were compared with the dentures constructed by the compression-molding technique and processed with heat-curing acrylic resin. The results indicate that the fluid resin dentures underwent more processing shrinkage (0.617%) than the conventionally processed dentures (0.377%). However, the fluid resin dentures seemed to function as well as the heat-cured dentures. The excessive reduction in the vertical dimension of the occlusion usually observed with fluid resin dentures was minimized; the average cusp height reduction was -0.089 mm. Individual tooth movement, voids, visible porosity, and other surface deficiencies were eliminated.


A multiple post-core technique.

A multiple post-core technique. An indirect technique to prepare a multirooted pulpless tooth to receive a crown is presented. The crown also may be made on the newly completed core and its die. The procedure promotes the use of a commercial dental laboratory. The system, which uses divergent roots, results in a cast core having maximum retention.


A procedure for repairing fractured post-core restorations. Two methods have been described for dealing with fractured or underextended posts in endodontically treated teeth. They seem to be adequate in preserving teeth that might otherwise have been lost.


Acrylic resin copings: an adjunct to fixed restorative dentistry. A simple technique for fabricating and several uses for acrylic resin copings have been presented. These techniques apply to many aspects of restorative dentistry and often are used in combination with each other. Master cast fabrication, interocclusal registrations, and verification of die accuracy can be done using the copings during a one-appointment sequence. The use of resin copings is especially helpful for the inexperienced dentist, permitting high quality dentistry with a minimum of mistakes and frustations. For the experienced fixed prosthodontist they provide another approach to treatment.


Effect of ultrasonic instrumentation on the retention of simulated cast crowns. The effect of ultrasonic instrumentation on the retention of cemented cast restorations was studied. Forces required to dislodge castings from specimen assemblies subjected to ultrasonic vibrations did not differ significantly from those required to cause failure of noninstrumented specimens. The results indicate that clinical application of the ultrasonic device would not affect adversely the retention of properly cemented and well fitting cast restorations.


Complete mandibular subperiosteal implants for edentulous mandibles. The complete mandibular subperiosteal implant is one of the oldest implant modalities. It has been serving thousands of people for over 25 years. All failures and problems created in the past have been due to the inadequate support and improper architectural design of the implant substructure. Through the mistakes made in experimentation over the years, better results have been achieved because of the improvement of the implant design. Proper evaluation and utilization of the available bone is essential for a successful prognosis for the edentulous mandible. The crossbar attachment that joins the four implant posts of the substructure provides better force distribution and less potential for resorption below the primary struts of the complete mandibular subperiosteal implant. The cast substructure rests on the bone and is covered by the mucoperiosteum. Satisfactory retention and stability is given to the definitive overdenture which is fitted over the protruding posts and crossbar design. The complete mandibular subperiosteal implant is a definite solution to the problem mandibular edentulous patient. Proper, careful, and conservative diagnosis is important. Skill, experience, and accuracy are major criteria for the success of a dental implant.


Fabrication of a single posterior intermediate restoration. Intermediate or temporary crowns are important in cast restoration procedures. A techniques is suggested whereby a metal shell crown is relined with autopolymerizing acrylic resin. It produces a restoration that (1) has good adaptation, (2) maintains gingival tissue health, (3) provides proximal and occlusal contacts, and (4) maintains tooth position.


A review of the association between intrauterine devices and acute pelvic inflammatory disease. Six controlled epidemiologic studies of the association between intrauterine device (IUD) use and development of acute pelvic inflammatory disease (PID) are reviewed. The strength and weaknesses of each study are discussed as well as the consistencies of the results. All six studies point in the same direction: IUD use is associated with approximately a three-to fivefold increased risk of PID. The consistency of the association in six different studies, in three different countries and by five different investigators is strong evidence that the association is one of cause and effect. Evidence is presented for the biologic plausability of the association. There also is evidence that copper IUDs do not appear to offer any protection from gonococcal PID. Teenagers appear as likely as older women to be similarly affected by the use of IUDs. There is the intriguing but uncomfirmed suggestion that nulliparous IUD users are more likely to suffer from acute PID than are multiparous users. A public health measure that would control this effect of IUD use is to decrease the use of IUDs in populations at high risk of PID.


Ibuprofen therapy for dysmenorrhea.

Ibuprofen therapy for dysmenorrhea. Thirty-three dysmenorrheic patients were given ibuprofen, aspirin and a placebo in a double-blind crossover study, with each drug taken during one of three successive menstrual cycles in random sequence. Paired drug comparisons demonstrated the statistical superiority of ibuprofen, as compared with the other two, for the relief of pain. Data evaluated according to patient drug preference showed similar results. The role of nonsteroidal antiinflammatory drugs in therapy for dysmenorrhea is discussed.


beta-D-Arabinofuran[1',2':4,5]oxazolo-1,3,5-triazine-5-N-methyl-4,6-dione and analogues, unusually specific immunosuppressive agents. Sequential treatment of the protected beta-D-arabinofuran[1',2':4,5]-2-aminooxazoline (2) with methyl isocyanate and diimidazole carbonyl afforded the 2,2'-anhydro-beta-D-arabinofuranosyl nucleoside, 6. Deprotection and hydrolysis yielded the corresponding arabinoside. Although the anhydronucleoside exhibited in vitro antiviral activity against herpes simplex type 1, it exacerbated the infection in vivo. Further examination uncovered an in vitro inhibition of the induction of a cell-mediated immune response without cytotoxicity.


A new class of antimalarial drugs: derivatives of benzothiopyrans. A series of substituted benzothiopyrans was synthesized and examined for antimalarial activity. Some were found to be active and curative at dose levels of 160--360 mg/kg against Plasmodium berghei in mice. Afew observations concerning structure-activity relationships were made. The benzothiopyrans were prepared by treatment of either the gem-dichloro- or the thionothioflavone intermediate with various primary amines. The thionothioflavone intermediates were made from thioflavones. Condensation of thiophenols with benzoyl acetates gave the thioflavones.


Inducibility of aryl hydrocarbon hydroxylase in cultured human lymphocytes: a study of repeatability. Modifications to the method for estimating aryl hydrocarbon hydroxylase (AHH) activity in cultured human lymphocytes are described. Despite the improvements to the technique it was not possible to show significant 'repeatability' of values for AHH induction over a period of 2 weeks or more. Significant repeatability could be seen when a blood sample from each subject was split into duplicates. However, this level of repeatability was low when considered for quantitative genetics purposes. Possible reasons for the poor repeatability have been discussed.