A review of research on genetic variation in physiological characteristics related to performance in dairy cattle.

Genetic influence on physiological characteristics ranges from single gene effects on amino acid substitutions in alternative forms of proteins to quantitative genetic effects on the amounts of enzymes and hormones. The number of loci involved in the control of quantitative variation in physiologically important substances is not known. A number of marker genes that affect blood antigens, serum and milk proteins, and enzymes have been identified in dairy cattle. However, relatively little is known about genetic effects on quantitative physiological traits in dairy cattle. Much more is known about the genetic control of hormones in laboratory animals. About 25% of the variation in milk production of dairy cows results from genetic differences. We need more studies of genetic influences on the various physiological and biochemical processes involved in the secretion of milk to reveal the mechanisms by which genetics influences the quantity and quality of milk produced by individual cows.


Distribution and effects of the 1/29 Robertsonian translocation in cattle.

The distribution and effects of the 1/29 translocation in cattle, defined with chromosome banding techniques, are described. Findings in different parts of the world are reported, and the origin of the translocation in some cases is explained. Geographical distribution as known at present reflects the areas in which chromosome investigations have been carried out rather than the true distribution. It is not known whether the occurrence of the 1/29 translocation in different geographical areas and breeds is due to recurrent mutation or distribution of an ancient mutation, but many observations point to the latter. Although direct observations of an increased embryonic mortality are lacking, reduced fertility of males and females heterozygous for 1/29 is established. No correlations of the 1/29 translocation with other characteristics have been found, and variability in incidence between different populations is probably due to genetic drift. The importance in animal breeding of introducing eradication programs is emphasized, and it is stressed that cattle populations using artificial insemination should undergo routine cytogenetic investigations.


Cytogenetic research techniques in humans and laboratory animals that can be applied most profitably to livestock.

The usefulness of various chromosome banding techniques, i.e., Q, C, G, R, Ag-NOR, and SCE, which are currently in use in many clinical cytogenetics labortories are discussed. Since C-banding revealed the location of constitutive heterochromatin, it must be applied in conjunction with Q, G, or R-banding techniques. For the longitudinal differentiation of mammalian chromosomes one can use either the G-banding or the Q-banding and, if possible, R-banding technique. The results of such studies should not only contribute to our understanding of cytogenetics of domestic animals but also assist breeding programs and improvement of livestock.


Wound healing: a review. II. Environmental factors affecting wound healing.

A variety of factors, both intrinsic and extrinsic, may influence the healing of wounds. Some of these influences are environmental in nature and subject to advantageous manipulation by the practitioner. In this article, the role of humidity, temperature, infection and oxygen tension on the process of wound healing will be discussed.


Pyogenic granuloma recurrent with satellite lesions.

Pyogenic granuloma recurrent with satellite lesions is an uncommon clinical entity. The condition occurs most often on the back of young individuals and runs a benign course. A case is presented and the literature is reviewed.


A selective ventilation distribution circuit (S.V.D.C).

A circuit for selective ventilation distribution (S.V.D.C.) is described. The use of the circuit is illustrated with five cases in which it was used. S.V.D.C. allowed: 1) Measurement of individual lung tidal volumes and pressures during the respiratory cycle. 2) Adjustment of the tidal volumes of both lungs in the most appropriate way for the patient. 3) Application of different degrees of PEEP to each lung. The circuit is easily built and managed, the patient is connected to it by a double lumen endotracheal tube (Carlens tube); the circuit requires only one respirator.


Physiological control of sibilant duration: insights afforded by speech compensation to dental prostheses.

Temporal relationships among tongue contact, phonation, and presence of frication were examined for /s/ and /z/. In cases where /s/ and /z/ were produced with a supraglottal articulation of the same duration, the duration of the resulting frication was 17 ms longer for /s/. The difference can be attributed to glottal activity. The presence of a unfamiliar dental prosthesis in the mouth caused the tongue to contact the alveolar ridge sooner and release later. This physiological effect was reflected in lengthening of frication for sibilants, but the acoustical consequences were greater and more reliable for /z/ than for /s/. Reasons for this difference were sought in adaptation of timing of tongue contact, and in aerodynamic conditions expected for voiced versus voiceless sibilants. A rapid adaptation of tongue contact timing was found, with the adaptation being greater for /s/. Timing of vocal fold adduction at the end of unvoiced sibilants, and its aerodynamic consequences, are suggested to consequences, are suggested to contribute to the relative stability of /s/ acoustical durations.


Denture service use in a selected population in a prepaid dental program.

Rates of use of dental services for a large population of employees enrolled in a prepayment plan were examined. During a three-year period, the number of complete denture services that were provided declined steadily. Also, the number of simple and surgical extractions decreased, and there was an increase in the rate of use of periodontic and endodontic services.


An evaluation of two methods for the quantitation of dentinal hypersensitivity.

In a well-controlled, double-blind, parallel study design using burnishing with 33% sodium fluoride paste and "sham" burnishing with a placebo paste, both a cold air stimulus method and an electrical stimulus method can discriminate between levels of dentinal hypersensitivity. Correlation between the scores obtained by the methods was significant. The electrical stimulus method discriminated between the sodium fluoride and placebo effects to a greater degree than did the cold air method. Use of these methods should broaden the scientific foundation and rationale for evaluating the condition of dentinal hypersensitivity and the agents designed for treatment of persons with this condition.


Clinical evaluation of a glass ionomer cement for restoration of cervical erosion.

The following conclusions can be made: A glass ionomer cement mixed in preweighed capsules to restore anatomically deficient cervical contours demonstrated bonding of the total restoration to tooth tissue without undercutting or pinning the tooth or relying on geometric design of a cavity preparation in approximately 95% of 113 restorations observed postoperatively for six months. Seven restorations showed partial loss of material. Seven of the 113 restorations, showed some marginal discoloration although no stain penetrated the interface of the tooth and restoration. For most cervical restorations, the glass ionomer cement produced a mismatch in "color, shade, and/or translucency" in relationship to the tooth. The probable reason for this is the opacity of the cement. An acceptable surface of the glass ionomer cement restorations can be established at a later finishing appointment. There is little evidence that roughness increased slightly during the six months. Patients' sensitivity to temperature and direct tactile contact diminished or was eliminated after placement of the restoration.


Repair technique for fractured anterior facings.

A technique for repairing the anterior region with use of aluminous porcelain-bonded-to-platinum-foil has been described. This technique produces a strong replacement and maintains the esthetic appearance of the original prosthesis.


Dimensional change of dental amalgam and a suggested correlation between marginal integrity and creep.

Discussion of a possible correlation of marginal integrity and degree of creep resulting from relative resistance of amalgams to deformation caused by expansion is included in this study of the effect of phase changes on the dimensional stability of amalgams.


The effect of the operator on the clinical performance of amalgam.

In this study, the effect of the operator on the clinical performance of amalgam was examined by evaluating the marginal fracture characteristics of four alloys placed by four operators. The results were as follows: --Marginal fracture was influenced by the operator. Therefore, careful attention should be given to the cavity design and the placement technique. --The interaction between operators and alloys was such that, for the worst alloy, there was no difference caused by the operators; for the intermediate alloys, there were large differences caused by the operators; and for the best alloy (a non-gamma 2 system), there was almost no difference caused by the operators. --The difference in marginal fracture characteristics among alloys was greater than the difference attributed to operators. --It appears that all practitioners should use non-gamma 2 amalgams because such amalgams perform better clinically and are less susceptible to variations in operators.


A comparative study of two pit and fissure sealants: three-year results in Augusta, Ga.

A total of 254 children were examined 36 months after a single application of sealant. In 128 children, 201 permanent first molars were treated with Delton, and, in 126 children, 205 permanent first molars were treated with Nuva-Seal. Delton was completely retained on 80% of all paired permanent first molars, partially retained on 10%, and completely lost on 10% of the study teeth. Nuva-Seal was completely retained on 60% of all paired permanent molars, partially retained on 21%, and completely lost on 19% of the study teeth. Delton was 69% effective in preventing occlusal caries on permanent first molars three years after a single application. Nuva-Seal was 39% effective in preventing occlusal caries on permanent first molars three years after a single application. Both sealants have been shown to prevent dental caries on permanent first molars of children three years after a single application.


Denture marking for identification.

A method for including the patient's name in the denture base material for identification purposes has been described. This simple procedure takes little time, has almost no cost, and is effective.


Effect of methods of tooth enamel preparation on the retentive strength of acid-etch composite resins.

The effect of three procedures of preparing enamel surface on the retentive strengths of Concise Enamel Bond. Adaptic acid etch, Restodent and Nurva-Seal/Nurva-Fil was investigated. Resins using an unfilled-filled resin combination(Concise Enamel Bond, Adaptic acid etch, and Nurva-Fil) had a significantly higher retentive strength when the enamel was prepared with a coarse diamond bur than when the surface was unprepared or prepared with a carbide bur. The different procedures of tooth preparation did not affect the retentive strength of the resin when only filled resin was used (Restodent).


Microleakage of amalgam restorations with high-copper content.

An in vitro study of microleakage of the margins of Class II restorations of several high-copper-content amalgams found that in general, leakage increased between 24 hours and a month, but decreased below the 24-hour values after six months; there were some differences in leakage among the products at 24 hours, but not aftersix months: the depth of leakage was not correlated with adaptation of the cavosurface margins; and the high-copper-content amalgams were similar to the conventional composition amalgam tested in regard to microleakage.


Study of a bland dentifrice for persons with radiation-induced mucositis and vesiculo-erosive disease.

Althought the patient group was limited to persons with radiation-induced mucositis, lichen planus, and erythema multiforme, the study indicates the potential usefulness of a bland dentifrice to other patients with sensitive mouths. Although it is presumed that regular brushing habits will aid in oral hygiene and health, the specific effect of a bland dentifrice on control of plaque, caries, and periodontal disease cannot be assessed in this preliminary study. Also, no comparison was made with cleaning techniques in which dentifrice is not used. Therefore, this study indicated only that dentifrice with reduced flavor, like the one used in this study, may encourage better oral hygiene through continued brushing when irritation from regular dentifrices discouages it.


Multidisciplinary management of Crouzon syndrome.

The comprehensive management of Crouzon syndrome in a 14-year-old girl has been presented. Because of the complexity of the facial and associated problems, a multidisciplinary approach is necessary to provide maximum functional and esthetic results; however, with such a cooperative interdisciplinary effort, the improvement and benefits derived for these patients are rewarding to all concerned.


Clinical therapy for accommodative responses: transfer effects upon performance.

A clinical therapy program featuring accommodative training was administered to a group of children with diagnosed disorders of accommodative function. The children ranged in age from six to twelve years. A group of subjects representing the same clinical population, and not differing significantly in age or grade level, acted as a control group. The control subjects participated in a therapy program of a similar duration, wherein perceptual-motor training (unrelated to the training of accommodative skills) was administered. A nearpoint pencil-and-paper task was administered to all subjects before and after the training programs, to assess changes in performance as a criterion of learning transfer and behavioral generalization. A significantly greater decrease in errors occurred in the group receiving the accommodative training as contrasted to the control group. No significant differences were found in the time scores. The results suggest that accommodative training, for children with diagnosed accommodative disorders, has transfer effects upon nearpoint performance relating to improved accuracy.


Reported ocular side effects of the ten most frequently prescribed drugs.

The ten drugs most frequently prescribed in 1977 are identified according to proprietary and non-proprietary names, pharmaceutical manufacturer, drug class, principal uses, and the ocular side effects which have been reported in the medical literature.


The United States Food and Drug Administration and the practice of optometry.

In the past decade the United States Food and Drug Administration has become increasingly involved with the regulation of materials used in the practice of optometry. It is the purpose of this paper to help the practitioner understand the FDA involvement, historically and legally, organization, how one can have input into the process, the procedures for testing and approving new drugs and devices, their regulation and the advantages and disadvantages of such control.


Immunofluorescent study of the spore antigens of proteolytic strains of Clostridium botulinum.

By means of the spore fluorescent antibody technique 31 strains of Clostridium botulinum types A (18 strains), B (10 strains) and F (3 strains) were found to belong to the same homogeneous group irrespective of their toxigenic types. Some strains of this species also cross-reacted with certain strains of Clostridium sporogenes types I, II and III and Clostridium histolyticum type II. By spore antigenic analysis it was found that Clostridium parabotulinum contained two components designated L and M, the former describing species specificity; the latter was the cross-reacting component shared by some strains of Clostridium sporogenes and Clostridium histolyticum. Following this, a scheme showing the distribution of spore antigenic components among various species of Clostridium was given.


The effect of an intramammary infusion of endotoxin on the establishment of experimental mastitis by Streptococcus agalactiae in the cow.

An infusion of E. coli endotoxin (10 microgram) into the mammary gland of the cow 16 h before experimental infection with St. agalactiae prevented the establishment of mastitis. A clinical examination of the affected gland did not reveal signs of inflammation, all organisms were eliminated from the milk by 36 h after infection. Mammary glands not pretreated with endotoxin, and injected with the same number of viable streptococci, showed signs of severe inflammation the milk yield was reduced and the injected pathogen could be isolated from the gland for up to 14 days when sampling was discontinued. The injection of endotoxin alone produced a rapid increase in the cell count of the milk, there were some signs of inflammation and 80% of the cells in the milk were neutrophils. The cell counts in the milk remained above normal for 7-10 days. Untreated control quarters appeared to be unaffected by the injection of E. coli endotoxin into an adjacent quarter, on the other hand the injection of St. agalactiae into the adjacent quarter on the same side of the udder produced a cell response which reached a peak after 2 days and returned to preinoculation levels by the fourth day. No inflammation was observed in these control quarters and no streptococci were isolated from the milk.


The relationship between rainfall and well water pollution in a West African (Gambian) village.

Water pollution was monitored in six Gambian village wells over a period of 8 months spanning the 5-month monomodal rains and the pre- and post-rains dry periods. Faecal coliform (FC) and faecal streptococci (FS) counts were high throughout and there was a massive increase associated with the onset of the rains, maximum counts exceeding 5 x 10(5)/100 ml. This pattern was largely sustained throughout the rainy season. Some individual variations in patterns of pollution could be ascribed to well design, in particular lining of the shaft, but no well was protected from the seasonal increase in faecal pollution. The source of the increased pollution appeared to be a flushing in of faecal material of indeterminate or mixed human and animal origin, probably over considerable distances. Peaks of pollution not associated with rainfall episodes could have resulted from the practice of communal laundering in the near vicinity of the wells. Specific pathogens including Salmonella spp. were isolated only intermittently. Attention has been drawn to a problem complicating the standard method for assessing FC counts.


Cross-contamination during the preparation of frozen chickens in the kitchen.

A study was made of the extent to which frozen broilers, contaminated with indicator organisms, can cause cross-contamination in the kitchen. In 60 kitchens a number of relevant objects were sampled during the preparation of contaminated frozen broilers. The results show that cross-contamination occurred in a high proportion of the kitchens examined. In many instances the indicator organism was still present on various objects even after rinsing, 'clearing' or washing up. In view of the possible risk of a cross-contamination with Salmonella spp. the importance of instructing food preparers is emphasized. No salmonellas could be found in the sinks of the 60 kitchens examined.


Enterotoxigenic enteric bacteria in foods and outbreaks of food-borne diseases in Sweden.

All of 86 food routinely examined for potentially pathogenic enteric bacteria were found to harbour one or more coliform species. None of the strains isolated produced heat-labile enterotoxin (LT) or showed invasive properties. The suckling mouse test indicated that one strain of Escherichia coli produced heat-stable enterotoxin (ST). Twelve incidents of suspected food poisoning were also investigated. In two of them the foods examined contained LT-producing strains of E. coli and in two there were LT-producing strains of Klebsiella pneumoniae. The counts of viable enterotoxigenic micro-organisms in these foods were 3000-30,000 E. coli/g and 50,000 to 1 million K. pneumoniae/g. The dominant symptom in all the incidents was watery diarrhoea. These seem to be the first reported cases of foodborne enterotoxigenic enteric bacteria in Europe. Though enterotoxigenic E. coli and related gram-negative enterotoxin-producing species are rare in correctly handled food in Sweden, these micro-organisms should be searched for when outbreaks of food poisoning are investigated.


Wound infections after surgery in a modern operating suite: clinical, bacteriological and epidemiological findings.

A prospective study of 2983 operations in general and orthopaedic surgery during 3 years performed in four operating theatres in a modern operating suite was carried out in order to evaluate the importance of airborne infection. Weekly nose-and-throat samples were taken from the surgical staff and pre-operative samples were taken from the nose, throat, skin and perineum of the patients. The air contamination was followed by using settle plates, which showed low mean counts of total bacteria of between 9 and 15 c.f.u./m(2)/min, with mean counts of Staph. aureus of between 0.03 and 0.06 c.f.u./m(2)/min. No correlation was found between the total number of bacteria and the incidence of post-operative infections or between the amount of Staph. aureus in the air and post-operative Staph. aureus infections. It was concluded that further increases in ventilation could, at best, only marginally affect the incidence of post-operative infection.The post-operative wound-infection rate was 9.0%. In various types of surgery, the infection rates varied from 5.3% in clean operations to 47.6% in dirty surgery. About one third of the infections were classified as moderate or severe.Adverse patient factors, such as immunodeficiency, steroid treatment, intensive care, etc., increased the rate to 15.0%; in ;normal' patients it was 3.8%.Among the bacteria isolated, gram-negative bacilli (31% of wounds), often together with other bacteria, and Staph. aureus (28%) predominated, but in 25% no specimens were taken.Of 76 post-operative Staph. aureus infections, 32 were caused by the patients' own strains, and of the remaining 44 infections, 22, or 8% of all infections, could be traced to strains present in the air and/or the respiratory tracts of staff during the operation.The length of pre-operative hospital stay had no influence on the carrier rate of Staph. aureus in patients. The incidence of post-operative wound infection was significantly higher in patients carrying Staph. aureus and was even higher if these bacteria were found on the skin.Patients with wound infections stayed, on an average, 15 days longer than patients without infections. In serious infections the increase in duration of stay was > 20 days. Although infections were commoner in older patients, the average additional hospital stay of infected patients did not increase with age. If the post-operative infections studied in a concurrent retrospective study are taken into account more than 12 000 bed-days were due to post-surgical wound infections in the period studied or, in other words, some 12 beds (corresponding to 5.5% of the total) were always occupied by infected patients.


IgG recruiting component (GRC): B cell-derived signal for IgG antibody synthesis.

The B cell-derived soluble factor that has been described as an IgG-recruiting component (GRC) was investigated to: a) ascertain whether it is governed by genetic constraints, b) determine what triggers its synthesis, and c) identify its cellular target. GRC has been shown to be unrestricted by histocompatibility barriers since it enhanced IgG antibody production in mice of diverse genetic backgrounds. Further, we report that eliminating IgG-bearing cells from B cells to be immunized in vitro allows T cells-replacing factor (TRF) to increase the number of IgM but not IgG PFC. Thus, TRF appears to act on IgM-bearing cells by expanding the IgM PFC number. Adding GRC 48 hr after the addition of TRF to such IgG-depleted cells caused expression of IgG PFC. Hence, B cells lacking IgG but possessing IgM surface immunoglobulins appear to be those that are acted upon by GRC. These data indicate that in whole splenic cell populations, GRC is derived from IgG-bearing B cells that are stimulated by antigen and a component in TRF.


Further evidence for the antibody nature of C3 nephritic factor (C3NeF).

C3 nephritic factor (C3NeF), found in the sera of some patients with membranoproliferative glomerulonephritis, has been shown to be composed of two heavy and two light chains, like IgG; in addition it shares antigenic determinants with IgG. Purified C3NeF binds to the amplification convertase of complement, C3b,Bb, and thereby prevents decay of its C3-cleaving potential. The capability of C3NeF to bind to C3b,Bb was used as a means for purifying C3NeF to homogeneity. The investigation described in this report suggests that binding of C3NeF to C3b,Bb occurs via the Fab portion of the molecule. Pepsin treatment of eight C3NeF preparations resulted in an average loss of 76% of C3NeF functional activity. Papain treatment induced a loss of approximately 90%. The decrease in functional activity could be attributed to the accelerated rate of dissociation of 125I-F(ab')2 and 125I-Fab fragments from stabilized cell-bound C3b,Bb. The dissociation rate of 125I-F(ab')2 from C3b,Bb was comparable with the decay of the functional activity of C3b,Bb stabilized by F(ab')2 or Fab fragments of C3NeF. Although these results suggest that the stabilizing activity of C3NeF is mediated by the Fab portion of the molecule, it was found that the Fc portion also contributes to its functional activity.


Ia antigens in mouse skin are predominantly expressed on Langerhans cells.

We have investigated the expression of products of the mouse major histocompatibility complex (MHC) on BALB/c and A/J epidermal cells. By using reagents with specificity for various products of the MHC in an indirect immunofluorescence procedure, we found that H-2 antigens are expressed on the vast majority of epidermal cells. Ia antigens, by contrast, are present on only 2.4 to 6.9% of all epidermal cells. These Ia-bearing cells bear a receptor for the Fc portion of IgG and ultrastructurally exhibit the characteristics of Langerhans cells. Ia antigens on Langerhans cells are encoded for by at least the I-A and I-E/C subregions of the MHC.


Activation of human B lymphocytes. XIV. Characterization of the precursor of the pokeweed mitogen-induced anti-sheep red blood cell plaque-forming cell.

The precursor of the pokeweed mitogen (PWM)-induced anti-sheep red blood cell (SRBC) plaque-forming cell (PFC) in human peripheral blood was characterized. By a variety of purification procedures, it was demonstrated to be a lymphocyte with surface characteristics of a B cell. Furthermore, it was demonstrated to bind to sheep erythrocytes (E) and thus segregated with the E-rosetting T cells when T cell enrichment was performed by differential fractionation of E-rosetting cells. This binding of the PFC precursor to E was blocked by pretreating the lymphocyte with anti-human Ig before E rosetting, indicating that the PFC precursor specifically bound to SRBC by a surface Ig molecule with binding specificity for sheep red blood cell determinants. Hence, the precursor of the PWM-triggered anti-SRBC PFC is a B lymphocyte with surface Ig expressing specificity for SRBC.


Membrane immunoglobulin is present on thymic and splenic lymphocytes of the trout Salmo gairdneri.

Three rabbit antisera raised to trout IgM showed positive immunofluorescent reactions with lymphocytes of trout spleen and thymus. These antisera showed no detectable cross-reactivity with keyhole limpet hemocyanin, as determined by direct radioimmune precipitation and adsorption, and did not appear to react significantly with carbohydrate moieties on trout IgM, as determined by the failure of proteolytic digests of trout IgM to inhibit in radioimmunoassay against intact trout IgM. Membrane immunoglobulin determinants were detectable on the membrane of both thymocytes and splenocytes with the lactoperoxidase-catalyzed iodination reaction. Radioimmunoassay of lysates of lymphocytes confirmed the association of immunoglobulin with trout thymocytes. By radioimmunoassay, lysates of thymic and splenic lymphocytes contained similar amounts of immunoglobulin, equivalent to approximately 8 X 10(4) molecules of IgM per cell (calculated as the monomer micro 2L2).


Use of antibodies against the label in non-separation non-isotopic immunoassay: 'indirect quenching' fluoroimmunoassay of proteins.

Antibodies against the label are introduced as a potentially useful reagent in nonisotopic immunoassay. They may permit end point determination without the need for a separation step, provided (i) that steric hindrance selectively prevents their binding to the antibody-bound fraction of the labelled antigen in an immunoassay mixture, and (ii) that their binding to the label in the free fraction results in a change in its signal. This 'indirect' approach was investigated in systems employing the fluorescein label and antibodies to fluorescein which quenched the fluorescence of free labelled antigen. 'Indirect quenching' fluoroimmunoassays for human serum albumin, human immunoglobulin G and human placental lactogen were demonstrated. These assays for proteins may be contrasted with conventional non-separation techniques, which are usually best suited to the determination of haptens.


Attachment of polymorphonuclear leukocytes to glomeruli with immune deposits.

A method for quantitative evaluation of a biological activity of immune complexes deposited in glomeruli is described. The activity reflects the activation of complement and is represented by the number of PMN attached to a glomerulus. It is possible to compare data from different individuals or different phases of glomerulonephritis. The complement component concerned is considered to be C3, activated through the classical or alternate pathway.


A pen smear technique for assays of rosette-forming lymphocytes.

A simple technique is described for the preparation of permanent stained smears of human E-rosette lymphocytes. Smears of the cells suspended in foetal calf serum were drawn as thin strips on slides with a pen nib. Such smears, after Romanowsky staining, and incorporating latex-particles phagocytosis as a marker for non-lymphoid cells, show excellent rosette preservation and permit easy distinction and counting of rosetting lymphocytes, non-rosetting lymphocytes, monocytes and granulocytes. The percentages of rosette-forming lymphocytes estimated on such smears correspond closely to those obtained from counts made on viable cell suspensions.


A method to evaluate the capacity of monocytes and macrophages to inhibit multiplication of an intracellular pathogen.

A new method to assess intracellular inhibition of multiplication or killing by normal and activated mouse peritoneal macrophages, human peripheral blood monocytes, and human monocyte-derived macrophages is described. This method involves measurement of incorporation of [3H]uracil into nucleic acids of the obligate intracellular parasite Toxoplasma gondii. The method utilizes the observation by Pfefferkorn and Pfefferkorn (1977) that [3H]uracil is incorporated in substantially greater amounts by T. gondii than by certain mammalian cell types. Differential uptake of [3H]uracil by Toxoplasma-infected and uninfected cultures allows for evaluation of the ability of macrophages or monocytes to inhibit or kill this organism. This method has been adapted to microsystem.


A modified mixed haemadsorption procedure for the detection and localisation of sperm antigens.

A mixed haemadsorption procedure for the detection and localisation of spermatozoal antigens is described. Sperm are immobilised by attaching them to the bases of wells on plastic plates using poly-L-lysine and antisera and sensitised red cells are then added to these wells. The technique uses simple reagents and allows sperm/red cell rosettes to be kept as permanent records.


The use of fluorescent labeled antigen to follow the fate of instilled immune complexes in the rabbit lung.

To follow the fate of exogenously introduced immune complexes in the rabbit lung, a direct labeling method was devised. Bovine serum albumin was incubated with fluorescein isothiocyanate, washed and then bound at equivalence with antibovine serum albumin. Immune complexes thus prepared are injected into a rabbit airway and the animal was sacrificed. Using chilled alcohol fixative and paraffin embedding 4 micrometer sections were prepared for light and fluorescent microscopy. This technique readily verifies that labeled antigen is taken up by alveolar macrophages. Electron microscopy using ferritin-antiferritin complexes corroborate these light findings.


Preparation of antigenically active membranes from solid murine lymphomas and fibrosarcomas.

Plasma membrane preparations were obtained from solid lymphosarcomas and fibrosarcomas by disrupting the tissues with a mechanical press. The subcellular fractions were isolated by differential centrifugations and examined by electron microscopy. The membrane-enriched fractions were also assayed for protein content and analyzed in SDS-polyacrylamide gel electrophoresis; a fairly good reproducibiltiy was found comparing different membrane preparations derived from the same tumor. The H-2 antigenic activity of the different membrane preparations was demonstrated in vitro by the inhibition of the C'-dependent 51Cr-release assay using monospecific H-2 alloantisera. The specificity of the assay was ascertained by the lack of inhibition of unrelated monospecific H-2 alloantisera and by a dose-response relationship between the amount of added membranes and the observed inhibition. The immunogenicity of the membranes was assessed in vivo by immunizing allogeneic mice that developed anti-H-2 alloantibodies. The possible mechanisms of the tissue disruption by the press are also discussed.


Ingestion of dyed-opsonised yeasts as a simple way of detecting phagocytes in lymphocyte preparations. Cytophilic binding of immunoglobulins by ingesting cells.

Procion-dyed yeasts which have been incubated in fresh serum and washed are readily ingested by human blood monocytes and tumour macrophages during a 30 min incubation period. Uptake is enhanced by centrifugation. Intracellular yeasts can be readily distinquished from extracellular by their much slower uptake of toluidine blue. Yeast ingestion is a much more reliable test for blood monocytes than the latex bead test and it is easier to read. The ingestion test may be combined with a rosette test for surface immunoglobulins (SmIg). Since the yeasts take up immunoglobulins from human serum during the complement-coating stage it is necessary, in a combined ingestion-SmIg test, to use fresh serum from another species (sheep) for opsonisation of the yeasts. A technique is described for reducing the number of immunoglobulin-bearing monocytes to a low level with a combined ingestion-SmIg rosette technique to detect residual immunoglobulin-bearing phagocytes.


A method for obtaining swine alveolar macrophages by segmental pulmonary lavage.

A technique for obtaining alveolar macrophages (AM) from anesthetized swine is described. Animals were intubated and segmental pulmonary lavage was performed utilizing a double lumen catheter (DLC). An average of 98% of the initial 100 ml lavage fluid was recovered with a typical yield of 1 x 10(8) free alveolar cells (FAC). AM were then separated from other FAC by their adherence to plastic. The final adherent cell population consisted of greater than 95% macrophage as determined by morphology and non-specific esterase activity. The technique described had no adverse effects on the animals even when repeated on the same animal several days later.


Transcutaneous leukocyte migration in vivo: cellular kinetics, platelet and C5a dependent activity.

A simple quantitative method for the measurement of leukotaxis in vivo is described. Duplicate skin chambers are placed over tape-stripped skin with 50% autologous serum--50% Hank's balanced salt solution as the attractant. Neutrophils predominate throughout 24 hr in this method with no change to mononuclear cells. A recommended modification of our original method is that chambers are sampled and removed after 8 hr rather than 24 hr since the majority of leukocyte migration occurs within the first 8 hr. Analysis of serum factors showed that heat-inactivation of the serum (56degreesC for 30 min) had no effect. However, depleting platelets or C5 from the serum removed approximately 90% of chemotactic activity for human neutrophils in vivo. Platelets, presumably through activity of their granules, enzymatically cleaves C5a from C5 in plasma. We conclude that C5a, after cleavage from C5, accounts for the majority of chemattractant activity in vivo.


Monocyte function in psoriasis.

Monocytes derived from the peripheral blood of psoriatic patients demonstrated a significantly higher phagocytic capacity (36 to 40%) for both 125I-labeled Shigella flexneri and 125I-labeled Staphylococcus albus compared with monocytes from healthy subjects. Monocytes from psoriatic patients showed a 2-to-4fold increase in bactericidal capacity against S. albus when compared with normal monocytes. However, the bactericidal capacity of monocytes from diphylline-treated patients did not differ from that of the control subjects. The antibody-dependent cellular cytotoxicity (ADCC) activity against EL4 tumor cells was found to be similar in both psoriatic patients and control subjects. It is postulated that these abnormalities of monocyte function in psoriasis are caused by a decreased cAMP/cGMP ratio similar to the decreased cAMP/cGMP ratio found in the lesional epidermis of this disease. It seems therefore, that the psoriatic abnormality is not confined to only one type of cell, the epidermal cell.


Detection of hapten erythrocyte conjugates in vitro and in vivo.

The studies presented demonstrate that immunofluorescent techniques are capable of detecting picryl chloride erythrocyte protein conjugates formed in vitro and in vivo, following infusion of picryl chloride into normal, sensitized and tolerant guinea pigs. These experiments and the finding that picryl erythrocyte stromata prepared in vitro, and in vivo from infused recipients, have the capacity fo sensitize fresh animals, support the view that infused picryl chloride conjugates with the red cell membrane in vivo.


Components of the Goeckerman regimen.

Although application of tar products and subsequent exposure to ultraviolet radiation (the Goeckerman regimen) has repeatedly been demonstrated to be effective therapy for psoriasis, the therapeutic role of each component has remained uncertain. Utilizing the bilateral comparison technique in 30 hospitalized patients with chronic stable plaque-type psoriasis vulgaris, we closely monitored the clinical responses to ultraviolet radiation (Westinghouse fluorescent FS40 bulbs, 290--400 nm) and a variety of tar preparations and lubricant vehicles in combination and separately. We found that: 1) 4 weeks of maximally-aggressive exposure to ultraviolet radiation alone will markedly improve, but not completely clear, psoriasis unless combined with a tar preparation or lubricating base; 2) 5% crude coal tar plus ultraviolet radiation offers no clear advantage or benefit over lubricating base plus ultraviolet radiation; and 3) none of the tar preparations tested offered any consistent advantage over any other preparation.


Failure to detect gliadin or gliadin binding sites in the skin of patients with dermatitis herpetiformis: immunofluorescence, organ culture and autoradiographic studies.

Recent investigations indicate an abnormal binding of gluten or gliadin to lymphocytes or intestinal mucosa cells in gluten sensitive enteropathy. Since dermatitis herpetiformis is closely associated to gluten sensitive enteropathy, similar receptors could also exist in the skin of patients with dermatitis herpetiformis. To prove this hypothesis, skin of normal volunteers and uninvolved skin of 3 patients with dermatitis herpetiformis was investigated for the presence of gliadin and gliadin binding sites. In vivo bound gliadin was not found by direct immunofluorescence using 3 different rabbit antigliadin antisera. In order to test skin for gliadin binding sites, normal sera and autologous dermatitis herpetiformis sera containing 25 mg% gliadin and tritium labeled gliadin, respectively, were used for incubation of normal and dermatitis herpetiformis skin cryocut sections and of normal and dermatitis herpetiformis skin specimens, grown under organ culture conditions. As checked by direct immunofluorescence and autoradiography, there was no specific in vitro binding of gliadin, indicating that gliadin does not fix to normal human or dermatitis herpetiformis skin. Thus, the role of gliadin in the fixation in vivo, of antibodies or immune complexes to skin in dermatitis herpetiformis, remains obscure.


Serologic responses to somatic O and colonization-factor antigens of enterotoxigenic Escherichia coli in travelers.

To improve the retrospective diagnoses of enterotoxigenic Escherichia coli (ETEC) as a cause of travelers' diarrhea, as well as to determine the presence of colonization-factor antigens in these infections, a study of serologic responses to antigens of ETEC was done. Paired sera from 60 United States students in Cholula, Puebla, Mexico, were analyzed for rises in titer of antibody to heat-labile toxin, eight somatic antigen O serogroups associated with ETEC, and two colonization-factor antigens, CFA/I and CFA/II. Only 9% had a response to O antigens, while 20% had responses to the colonization-factor antigens. Response to the colonization-factor antigens correlated significantly with response to the heat-labile toxin and with culture evidence of ETEC infection. Serologic studies confirmed that colonization-factor antigen has a role in naturally acquired cases of travelers' diarrhea and that it can be used as an additional determinant of infection with ETEC.


Characterization of yeast agglutinins in lavage fluid from lungs of rabbits.

Rabbits were challenged intratracheally with 10(8) Candida albicans or Torulopsis glabrata, and their lungs were lavaged 5, 60, and 120 min later. Initial lavage samples showed significant agglutination of yeasts, followed by the development of larger aggregates in association with alveolar macrophages. To investigate this early agglutination reaction, lungs of normal rabbits were lavaged with heparinized saline, and after alveolar macrophages were discarded, the cell-free lavage fluid was centrifuged at 25,000 g to recover a small, whitish, surface-active pellet (F fraction). The supernatant was concentrated 15-fold by vacuum dialysis (P fraction). When Candida species, T. glabrata, and Saccharomyces cerevisiae were incubated with the F fraction, serial colony counts decreased eight- to 20-fold with every yeast species tested except S. cerevisiae and Candida krusei. Decrease in colony counts was associated with yeast agglutination. The F fraction was further separated by ethanol-ether extraction, and yeast agglutination was seen only in the protein-rich fraction. Further separation of this protein-rich fraction by polyacrylamide gel electrophoresis yielded three bands, one of which, with a molecular size of about 10(4) daltons, agglutinated C. albicans. IgA in the P fraction also agglutinated C. albicans, although not as dramatically as the F fraction.


Interposed bone-graft augmentation of the atrophic mandible (a progress report).

A follow-up study on 41 patients who had augmentation of the atrophic mandible by interposed bone graft is presented. Special emphasis has been put on the prosthetic implications. The rapid reduction in height measured postoperatively appeared almost to cease after 6 months. Some of the possible causes of this phenomenon are discussed.


The Kaleff-Hollwich technique and results of external dacryocysto-rhinostomy operation.

After a review of the history of lacrimal surgery the author describes the techniques of dacryocystorhinostomy which are currently performed. The ideal method is that of Ohm (1921) and Dupuy-Dutemps (1921) with its totally closed mucosal anastomosis. Because of the technical problems demonstrated with this technique the author recommends that of Kaleff (1937), modified by Hollwich (1977). The advantages of this method are: 1. The almost closed mucosal cavity which permits primary would healing. 2. The easy strain-free practicability particularly in cases of small scarred sac and pre-positioned ethmoid cells. 3. The sure fixation of the mucosal roof at the subcutis particularly in cases of marked swelling. Finally a survey of long-term and short term observations on all 324 cases from 1964 to 1977 is given.


Studies with fragments of a highly active analogue of luteinizing hormone releasing hormone.

The minimal structural requirements for gonadotrophin releasing activity were studied with fragments of a highly active analogue of luteinizing hormone releasing hormone (LH-RH), [D-Ser(But)6]LH-RH(1-9)nonapeptide-ethylamide (Hoe 766). All fragments are related to the C-terminal structure of LH-RH and have increased enzyme stability. Ovulation in phenobarbitone-blocked rats was induced with a median effective dose/rat, of 1.9 microgram of the (3-9)-heptapeptide, Trp-Ser-Tyr-D-Ser(But)-Leu-Arg-Pro-ethylamide and 6.8, 18.0 and 38.3 microgram for the (4-9), (5-9) and (6-9) fragments respectively. The (3-9)- heptapeptide and (4-9)-hexapeptide induced release of LH and FSH in phenobarbitone-blocked rats with a ratio similar to that of LH-RH. Degradation of LH-RH by enzyme preparations of liver, kidney and hypothalamic or anterior pituitary tissue was not modified by addition of the (3-9)-heptapeptide fragment. The organ distribution of the 125I-labelled (3-9)-heptapeptide fragments was similar to LH-RH, but not to Hoe 766. The peptide accumulated in liver and kidney, but was eliminated from the anterior pituitary gland 15 min after i.v. injection, whereas Hoe 766 showed progressive accumulation in the pituitary gland (tissue:plasma ratio = 6.6 after 60 min). In contrast to C-terminal fragments of LH-RH, the corresponding fragments of nonapeptide analogues retained significant biological activity, and the minimal structural requirements for LH release may be related to the C-terminal sequence of LH-RH.


Ontogeny and localization of the crystallins during lens development in normal and Hy-1 (hyperplastic lens epithelium) chick embryos.

A strain of chickens selected for high growth rate has been found to exhibit an anomalous eye lens morphology indicating a failure of the normal process of growth regulation. Hyperplasia of the lens epithelium and annular pad, often with fiber formation, has recently been described in day-old chicks of this strain, termed Hy-1 (Clayton, 1975). The earliest evidence of this condition in this study has been found in the 11-day embryonic Hy-1 lens. Before this time, no definitive lens abnormality could be detected histologically in the Hy-1 embryos. However, the indirect immunofluorescence technique had revealed early temporal and spatial differences with regard to the lens crystallins. Antibodies, specific for delta, cathodal beta, anodal beta and alpha crystallins, were applied to sections through the lens of 2 1/2-, 3-, 3 1/2, 4-, 5-, 8- and 16-day embryonic and 1-day post-hatch normal and Hy-1 chicks. delta crystallin appears precociously in the external layer, and alpha crystallin in the prospective fiber region, of the lens rudiment of Hy-1 embryos. Both anodal and cathodal beta crystallins are retarded, however, in their appearance in the external layer/epithelium of Hy-1 lenses. Localization of the crystallin classes within the lenses of the two strains continues to vary during lens differentiation until 1 day post-hatch, at which time and during late embryogenesis annular pad and epithelium abnormalities can be frequently be seen in the Hy-1 lens. This inability to control normal lens histogenesis thus manifests itself early as alterations in the appearance of an organ-specific gene product, the crystallins.


Rejection of first-set skin allografts in man. the microvasculature is the critical target of the immune response.

Recent reports of microvascular injury in delayed hypersensitivity skin reactions prompted us to reexamine the pathogenesis of first-set skin allograft rejection in man using morphologic techniques that allowed both extensive vessel sampling and unequivocal evaluation of microvascular endothelium. We here report that widespread microvascular damage is a characteristic, early consequence of the cellular immune response to first-set human skin allografts and is qualitatively similar to, but substantially more extensive than, that occurring in delayed hypersensitivity reactions. Microvascular damage in invariably preceded significant epithelial necrosis and affected initially and primarily those venules, arterioles, and small veins enveloped by lymphocytes. Vessels of both the allograft itself and the underlying graft bed (recipient tissue) were equally affected. These data suggest that endothelial cells of the microvasculature are the critical target of the immune response in first-set vascularized skin allograft rejection in man and that rejection can be attributed largely to ischemic infarction resulting from extensive microvascular damage. Other mechanisms, such as direct cellular contacts between infiltrating lymphocytes and epithelium, apparently played only a minor role. The findings presented here indicate that the rejection of first-set vascularized skin allografts, though induced by immunologically specific mechanisms, is primarily effected by final pathways that are relatively nonspecific and that may cause damage to both foreign and host vessels and cells. Rather than contradicting studies demonstrating the exquisite specificity of allograft rejection in other systems, these findings provide a further example of the heterogeneity of the cellular immune response. Recognition of the critical role of immunologically mediated microvascular injury may prove important both for an understanding of the biology of allograft rejection and for strategies aimed at prolonging allograft survival.


[Determination of alpha-amylase by an enzymatic kinetic method on the ABA-100 (author's transl)].

The enzymatic method of H. W. Schiwara (1972) Z. Klim. Chem. Klin. Biochem. 10,12--16 (reagents by Smith Kline Instruments), using the enzymatic reaction sequence alpha-amylase -- alpha-glucosidase -- hexokinase/glucose 6-phosphate dehydrogenase for the determination of alpha-amylase was evaluated on the ABA-100. The coefficient of variation for control sera and human pooled serum was 0.9--4.2% within series, and 1.4--6.6% day to day. Reference values for a healthy population (212 blood donors) in sera were 13--79 U/1 (+/- 2 SD), mean 46 U/1. In catch urines the values did not show a normal distribution; the minimal and maximal range for men was 58--385 U/1, for women 7--318 U/1. The kinetic curve of the enzymatic test was measured and the influence of glucose and linearity studied. In comparison with the enzymatic test, the chromogenic method Amlyochrom Roche was tested on the sera and urine of patients. The coefficient of correlation in sera was r = 0.975, in urine r = 0.965.


A diagnostic strategy for myocardial infarction.

In attempting to make the diagnosis of myocardial infarction, the family physician has available an increasing array of enzyme and nuclear imaging techniques to add to the clinical and electrocardiographic findings. In this review several of the new diagnostic tests are described, and their role is discussed both in supplementing and replacing older diagnostic tests. A general strategy for employing both old and new tests is proposed, with a goal of achieving both increased diagnostic accuracy and reduced charges for laboratory tests.


Psychiatric complications of medical drugs.

General drug toxicity has long been a concern of physicians. Recently, there has been increasing concern about the psychological side effects of drugs. This paper reviews the literature on psychological side effects of those drugs which have been most studied in recent years. It also includes a section reviewing the literature on miscellaneous drugs associated with psychological symptoms. This review, although not exhaustive, is intended to alert the physician to drug related causes for psychological symptoms which patients may experience while taking drugs.


Evidence for an intracellular calcium store releasable by surface stimuli ifibroblasts (L cells).

A spontaneously occurring or electrically elicited hyperpolarizing activation (HA) in L cells was previously shown to be due to a specific increase in the membrane K+ permeability (Nelson et at. 1972. J. Gen. Physiol. 60:58--71). Intracellular injection of Ca++ elicits an identical hyperpolarizing response which suggests that the increased K+ permeability associated with the HA is mediated by an increase in cytoplasmic Ca++. In zero-Ca, EGTA-containing saline the proportion of cells in which HA's can be evoked decreases, but the amplitude of those HA's that are produced is comparable to that of HA's in normal Ca saline. Co++ does block the HA but only after a period of 2 h or longer; D-600 does not affect the HA. The observations, with others, suggest that the primary source of the Ca mediating the HA response is intracellular. In L cells the endoplasmic reticulum forms morphologically specialized appositions with the surface membrane which resemble structures at the triads of muscle that are thought to mediate coupling between surface membrane electrical activity and contraction via Ca release from the sarcoplasmic reticulum. The similar structures in L cells may mediate coupling between surface membrane electrical, mechanical, or chemical stimuli and the HA response via release of Ca from the endoplasmic reticulum. Surface-coupled release of Ca from intracellular stores might also regulate a number of other intracellular functions in nonmuscle cells.


A model for hyphal growth and branching.

A mathematical model for hyphal growth and branching is described which relates cytological events within hyphae to mycelial growth kinetics. Essentially the model quantifies qualitative theories of hyphal growth in which it is proposed that vesicles containing wall precursors and/or enzymes required for wall synthesis are generated at a constant rate throughout a mycelium and travel to the tips of hyphae where they fuse with the plasma membrane, liberating their contents into the wall and increasing the surface area of the hypha to give elongation. The hypothesis that there is a duplication cycle in hyphae which is equivalent to the cell cycle observed in unicellular micro-organisms is also included in the model. Predictions from the model are compared with experimentally observed growth kinetics of mycelia of Geotrichum candidum and Aspergillus nidulans. The finite difference model which was constructed is capable of predicting changes in hyphal length and in the number and positions of branches and septa on the basis of changes in vesicle and nuclear concentration. Predictions were obtained using the model which were in good agreement with experimentally observed data.


Mutants of Escherichia coli K12 accumulating porphobilinogen: a new locus, hemC.

Mutants of Escherichia coli K12 which accumulated the haem precursor porphobilinogen are described. The mutants grew very slowly on carbon and energy sources which K12 uses only oxidatively, and they had low catalase activities, suggesting that they were deficient in haem. Extracts had one-tenth of the parental activity of the enzyme porphobilinogen deaminase. In transduction, the mutation mapped close to genes ilvD and metE at minute 84. The gene was tentatively identified as hemC, coding for porphobilinogen deaminase. The gene symbol hemC replaces the earlier and temporary symbol popE.


The influence of the growth environment on the stability of a drug resistance plasmid in Escherichia coli K12.

Populations of Escherichi coli K12 containing the plasmid TP120 which coded for resistance to ampicillin, streptomycin, sulphonamide and tetracycline were grown in a chemostat under carbon-limited and phosphorus-limited conditions. With time resistance to one or more of the drugs was lost, resulting in the production of mutant populations which were more competitive than the parent population. The resistance to tetracycline was always lost under both carbon and phosphorus limitations, but resistance to the other three drugs was lost only during phosphate-limited growth. Strains of E. coli which had lost resistance to one or more of the drugs were capable of higher maximum specific growth rates than the parent strain.


The effect of varying dietary zinc levels on growth and antibody-mediated response in two strains of mice.

The objectives of the present study were to determine the zinc requirement of two strains of young growing female mice. The strains tested were outbred Swiss mice and inbred A/J mice. In addition to using growth as a criteria of zinc adequacy, the response to immunization with sheep red blood cells (SRBC) was measured in each strain at various dietary zinc levels. The dietary levels of zinc fed in a biotin-fortified egg white diet were: 0.7, 3.3, 5.9, 8.2, 11.0 and 31.4 mg/kg. It was found during a 3-week experimental period that the outbred Swiss mice attained maximum growth and normal antibody-mediated response at a zinc level in the diet of 5.9 mg/kg. The inbred A/J mice in a 2-week experimental period were also able to attain maximum growth and normal antibody-mediated response at 5.9 mg Zn/kg. It is concluded that there were no differences in the zinc requirement for growth of the two strains of mice used and also that the zinc requirement for immunological competency as measured by the Jerne plaque assay using SRBC antigen were similar. The results indicate that the mouse has a lower dietary requirement for zinc than the rat.


Distribution and evaluation of complete dentures in a population in northern Norway.

The frequency and distribution of complete dentures were studied in a population of 358 persons aged 20--69 living in a community in Northern Norway. Among the 83% who attended the investigation, 49% had a maxillary and 26% a mandibular denture. The occurrence of dentures increased with increasing age and with decreasing income and/or social class, while dentures were almost equally common in both sexes, when differences of age and income were taken into account. Of the participants between 50--69 years 39% had received their first maxillary denture at the age 17--24 years. In the age group 30--49 years the corresponding percentage was 20. Forty-four percent of the participants had maxillary dentures and 33% mandibular dentures which were older than 10 years. According to an index on the clinical evaluation of complete dentures as well as to the denture wearers' own opinion, the insufficiency of the dentures tended to increase with increasing age of the dentures. Sex, age, income and social class, however, were found to have only a minor effect on the age and the condition of the dentures as well as on the denture wearers' degree of satisfaction with their dentures. Persons who had natural mandibular teeth, tended to be less satisfied with their maxillary dentures than persons with complete dentures in both jaws.


Tensile strength of the bond between resin to enamel etched with phosphoric acid containing fluoride.

The tensile bond strength of Epoxylite 9075 and Enamelite to enamel treated with NaF and SnF2, at two concentrations, in the etching acid (H3PO4) was determined. The average fracture stress of those samples in which fracture occurred in the resin only, may be considered as the tensile strength of the resin, 69.8 +/- 5.6 kg/cm2. The mean fracture stresses of the Epoxy 9075 systems etched with pure phosphoric acid or with acid solutions containing 0.5% F salts were significantly higher than those treated with acid solutions containing 2% F salts. Incorporation of NaF or SnF2 in the etching solutions highly increased the fluoride concentration of enamel. The fluoride increase dependend on the fluoride concentration of the etching solution and was greater for NaF than SnF2.


Evaluation of alternative alloys to precious ceramic alloys. 1. Mechanical properties.

In the first part of this study, the microstructures and the mechanical properties of precious, semi-precious, and nonprecious dental casting alloys for the porcelain-baked-to-metal technique have been determined. The semi-precious alloys contained only 50% gold, and palladium, silver, and some base metals. The nonprecious alloys were of the nickel-chromium type. Discs and miniaturized tensile bars have been cast and tested either in the as cast condition, or after a simulation of the various porcelain bakes. Proof stress, ultimate tensile strength, elongation, and plastic stiffness have been measured and results compared by use of analyses of variance. The microstructure examination shows that the simulation of the porcelain bakes improves the homogeneity of the precious and semi-precious alloys. Simultaneously, the mechanical properties of the same alloys are also improved. One semi-precious alloy, still under development at the time of these tests, has its mechanical characteristics markedly downgraded by the thermal treatments. The nickel-chromium alloys exhibit the best range of mechanical properties for the porcelain-baked-to-metal technique, when considering the three most relevant properties: proof stress, plastic stiffness, and modulus of elasticity.


Neonatal solitary renal cysts associated with posterior urethral valves.

Large simple cysts of the kidney are common findings in adults but are extremely rare in neonates. Three cases of large solitary renal cysts in newborn boys associated with posterior urethral valves are described. The pathogenesis, diagnosis, treatment, and differentiation from urinoma secondary to spontaneous urinary extravasation are discussed.


Congenital lip pits and Hirschsprung's disease.

A newborn infant with aganglionosis of the entire colon and terminal ileum also had congenital lip pits and a submucous cleft palate. These anomalies may be added to the growing list of conditions associated with Hirschsprung's disease.


Full-thickness rectal punch biopsy for the diagnosis of Hirschsprung's disease.

The authors propose a full-thickness rectal punch biopsy method for the diagnosis of Hirschsprung's disease when the results of other diagnostic investigations have been equivocal. This procedure has been utilized in 48 patients in the last 8 yr and the method was diagnostically reliable.


Experience with the van der Meulen one-stage hypospadias repair.

The van der Meulen one-stage hypospadias repair for distal hypospadias with minimal or nor chordee is described. It has been used in 65 cases and the results were good or excellent in 50 patients. There were no instances of postoperative urethral fistula.


Don't get hooked on your sponges.

Attention is given to the poor design of a disposable cellulose sponge that results in frequent hooking of sutures during microsurgical procedures. Suggestions for improvement are made.


Alveolar bone mass using 125I absorptiometry.

Small changes in alveolar bone mass are very difficult to detect using radiograms. A method is described for registering minute changes in bone mass in restricted parts of the jaw. The method is based on the use of collimated monenergetic radiation from 125I and replacement of the roentgen film by a non-image forming detector. As the apparatus also can be used for measuring the object thickness, the attenuation formula can be used for calculating the alveolar bone mass. The radiation dose can be kept an extremely low level and the reproducibility of the measurements is high. The technique therefore may be used for long-term studies of changes in alveolar bone mass. The alveolar bone mass responds rapidly to changes in the neighboring tissues. The reaction following gingivectomy or dental trauma is characterized by a significant loss of alveolar bone mass initially. After 4 weeks an increase in the alveolar bone mass is noted and found to continue during the subsequent months.


Removal of amalgam overhangs. A profilometric and scanning electron microscopic evaluation.

Forty recently extracted teeth with Class II amalgam restorations with overhangs were divided into four groups of 10 teeth each. The overhangs were removed using one of the following instruments in each group: trimmer, chisel, surgical blade and reciprocating motordriven diamond tip. Instrumentation was performed until no irregularity could be detected clinically with a No. 3 explorer. The tooth-amalgam interfaces were examined by combined use of a surface measuring instrument and a scanning electron microscope. Four tracings from each specimen were recorded and the discrepancy at the tooth-restoration interface was measured. The mean score for each tooth was determined, and the results were analyzed statistically. The tooth-restoration interfaces were photographed at 140 magnification with the SEM. The results indicated that all instruments tested were effective in removing overhangs, since none of the mean discrepancies registered after instrumentation exceed 4 micron. The surgical blade, and especially the reciprocating motor-driven diamond tip eliminated overhangs better than the chisel. Both SEM photographs and the profilometric tracings revealed gaps or voids at the toothamalgam interface, ranging from 10 to 50 micron.


Histological assessment of autogenous bone graft. A case report and critical evaluation.

A histological study of the site of a clinically successful bone graft revealed the presence of a downgrowing junctional epithelium between the root surface and the altered graft bone. No new cementum could be seen associated with the osseous autograft, nor was a functional periodontal ligament in evidence adjacent to the grafted bone. It is suggested that the presence of newly formed bone on surgical reentry following bone grafting in periodontal lesions does not necessarily imply that regeneration of the periodontium has occurred.


Sulcular exudate flow in gingival inflammation.

Sulcular exudate flow measurements were obtained from 45 subjects and compared to the clinical as well as histologic degrees of inflammation. The results of this investigation demonstrated no statistically significant difference between exudate flow and the clinical degree of inflammation while demonstrating a statistically significant difference between exudate flow and the clinical assessment of inflammation. It was proposed that current clinical indices do not accurately reflect the microscopic degree of gingival inflammation.


New compounds: arylsulfonylhydrazones derived from various heterocycles.

Ten arylsulfonylhydrazones were prepared from various heterocycles. The antimicrobial activity of these compounds was investigated, as was the cytotoxic activity of one of them.


Pepsin secretion in anaesthetized cats stimulated by pentagastrin and gastrin II in the presence or absence of secretin.

1. In fasting anaesthetized cats pentagastrin and gastrin II, infused alone in doses which evoked a large acid response, did not stimulate the secretion of pepsin. However, peptic secretion increased significantly when either acid stimulant was infused simultaneously with a dose od Boots' secretin, in itself below the threshold for peptic stimulation. 2. The potentiation by pentagastrin and gastrin II of the peptic response to secretin was similar to the potentiation observed when caerulein, histamine and N-methyl histamine are given with secretin, an effect we have attributed to a non-specific increase of gastric mucosal blood flow which accompanies the infusion of these acid stimulants and effectively increases the concentration of secretin delivered at the site of the chief cell in the gastric mucous membrane.


The effect of pentagastrin (I.C.I. 50, 123) on peptic secretion in man.

1. We have studied the peptic responses of the intact human stomach to stimulation by doses of pentagastrin which elicit a maximal acid response.2. In twelve patients an intramuscular injection of pentagastrin (6 mug/kg) was followed by a prompt increase in acid output which attained a peak value eight times higher than the basal value in the period 15-30 min after stimulation. The pattern of the peptic response was similar, but the peak output of pepsin was only three times the output in unstimulated juice.3. In ten subjects the acid and peptic responses to I.V. infusion of pentagastrin (1.2 mug/kg per hr) were studied using a gastric perfusion technique with (14)C-labelled polyethylene glycol as non-absorbable marker. In seven of these ten subjects the pH of duodenal contents exceeded 6, and less than 0.5 m-mole HCl per 15 min entered the duodenum throughout the tests. In this subgroup pentagastrin evoked a strong acid response but no peptic response.4. In three subjects the pH of duodenal juice was less than 5.5 at times when more than 1 m-mole HCl per 15 min entered the duodenum. The acid response to pentagastrin differed considerably in the three subjects, but in each individual the output of pepsin increased each time an excess of HCl entered the duodenum.5. Since pentagastrin infused in a dose which maximally stimulates acid did not significantly increase the output of pepsin provided no HCl entered the duodenum we conclude that pentagastrin does not stimulate the secretion of pepsin in man. The transient insignificant peptic response to pentagastrin infusions, and the small but significant response to bolus injections of pentagastrin, can be explained as a wash-out phenomenon.


The effect of relining on the accuracy and stability of maxillary complete dentures--an in vitro and in vivo study.

A technique was developed for evaluating in vitro the accuracy or fit of experimental denture bases using a low-viscosity impression material for determining the space between the master die and the processed denture base. These measurements indicated that relining heat-cured maxillary denture bases with autopolymerizing acrylic resin improved their adaptation to the ridges. Interestingly, if no teeth were present in the heat-cured denture base, markedly less distortion occurred after processing. Limited clinical measurements on the stability of maxillary dentures in function showed no statistically significant change in stability after relining, but the trend was toward increased stability with the relined denture.


In vitro comparison of intact endodontically treated teeth with and without endo-post reinforcement.

In an in vitro experiment, the failure loads of 59 intact endodontically treated teeth with and without Kerr Endo-Post reinforcement were compared. Fifty-eight teeth fractured below the cementoenamel junction. One tooth fractured through the pulp chamber with a chisel fracture involving both the crown and root. Teeth without posts fractured through the middle or coronal one third of the root. Teeth with posts fractured through the body of the post. No statistically significant reinforcement was demonstrated by cementing a Kerr Endo-Post No. 100 into a sound endodontically treated tooth.


Semiprecision rest system for distal-extension removable partial dentures.

The history of the nonlocking type of intracoronal semiprecision rest has been traced from its origins with Neurohr in 1930, up to its present use as the Thompson dowel rest. The advantages of the use of this deep rest design and the clasp arm design for primary retention have been discussed. The Blatterfein modification of the lingual clasp arm has been introduced to overcome the problems of breakage and lack of stabilization which are present with the Thompson, Van Dam, and Wands designs.


A resilient lining material for the retention of maxillofacial prostheses.

The use of a resilient denture lining material and the rationale for the selection of the particular material used has been described. A resilient lining material provides primary retention for prostheses that may be difficult or impossible to obtain by other means. The improved compatibility of delicate tissues with a resilient material as compared to a rigid material has also been discussed.


Current concepts in cranioplasty.

A review of the methods of cranioplasty has been presented. A method of prefabrication of an alloplastic cranial implant has been described as well as a review of 40 patients with whom this technique was used.


The influence of the loss of teeth and attrition on the articular eminence.

A review of the literature revealed that changes in the articular eminence associated with changes in the dentition were usually overlooked in most reports. An attempt was made to determine whether changes in attrition and loss of teeth would correlate with a change (decreased angulation) in the articular eminence. The population consisted of 103 adult skulls and mandibles of both sexes and three different races. They included partial and totol edentulism, mild to severe attrition, and complete dentitions in good condition. An impression of each of the 206 articular eminences was made and the angulation established. The data were transferred to computer cards and a statistical analysis performed. The level of significance for each of the variables was established and conclusions were made.


Patient response to variations in denture technique. Part III: Five-year subjective evaluation.

Dentures were constructed for 64 patients by two different techniques. One technique, designated as "complex," involved more complicated procedures such as a true hinge axis location, balanced occlusion, dentures remounted on an articulator after processing with new interocclusal records, and occlusal corrections made on the articulator. The "standard" technique involved an arbitrary mounting of the maxillary cast on the articulator, arranging the occlusion with centric relation coincident with centric occlusion but without a balanced occlusion, and making occlusal corrections in the mouth. Subjective evaluations were made for each of the 64 patients at initial placement of the dentures and for all active patients at five yearly recall visits following placement. The evaluation method was designed to determine clinical differences between the dentures made by the two techniques. At the end of 5 years, the data obtained at five yearly recall visits were subjected to statistical testing. These tests were performed to determine if the technique by which the dentures were made had any effect on the performance of the dentures that could be detected clinically. The results of the test showed that there was no significant difference between dentures made using two denture techniques that could be detected by subjective means.


Root retention and removable partial denture design.

The position of a retained root for preservation of a ridge requires modification of the design of a distal-extension removable partial denture on the side of the retained root. A model with silicone rubber over the ridges and simulated retained roots was fabricated. A framework with mesial rests, distal proximal plates, and I-bar clasp arms was fitted to it. A pencil lead was attached to the framework to record the arcs of rotation of the I-bar clasp arm. The movements and the fulcrums of the prosthesis were changed by the presence of simulated retained roots posterior to the distal abutment.


A clinical survey of gagging patients.

A clinical investigation was carried out on 74 dental patients who were suffering from a severe gagging reflex. The most common stimulating factor was the maxillary denture. Routine history and clinical examination were carried out for each patient, and lateral skull radiographs and an Eysenck Personality Inventory were completed for some of the patients. Treatment consisted of the use of an acrylic resin training base combined with relaxation therapy and heterohypnotic techniques. The results of this ongoing study were: (1) there were no consistent features of the group which differentiated them from control groups; (2) a number of patients were insufficiently motivated and discontinued treatment; and (3) some patients who were declared completely cured suffered relapses.


Cost analysis of relined mercaptan rubber impressions.

An investigation was conducted to compare the time and amount of material used in a corrective reline impression procedure and in a complete remake of a new double-mix impression. The reline technique required 22.22 gm less material, and the reline technique was achieved in approximately 7.6 minutes less time than that required for a complete remake. This results in a monetary saving while preserving quality.


The Micro-Ring for full subperiosteal implant and prosthesis construction.

This technique was developed to overcome some of the difficulties experienced by the dentist in construction and maintenance of an implant denture. Laboratory construction time is greatly reduced in both the subperiosteal and the implant prosthesis. The greatest advantages of the technique are accurate and positive construction and predictable results.


Adhesion between copper-plated acrylic tray resin and a polysulfide rubber impression material.

The method of copper plating on acrylic resin was developed, and the bond strength to polysulfide rubber was measured in comparison with that of the adhesive coating. The bond strength with copper plating was greater than with adhesive coating. The specimens with adhesive coating failed due to a rupture occurring at the elastomer-adhesive interface, while those with copper plating had cohesive-adhesive failure. The method of copper plating on acrylic resin improved the adhesion between the polysulfide rubber and the custom-built acrylic resin tray.


Technique for making a customized shade guide.

A technique has been presented for making a custom shade guide that provides a direct visual means for conveying color information to the laboratory technician. The technique consists of applying pigment directly to acrylic resin denture teeth using colored drawing pencils. This technique was originated by Dr. Royal Norman of Omaha, Nebraska. One of the authors (S. W. A.) first saw Dr. Norman present it to the USAF Area Dental Laboratory Workshop, Westover AFB, Mass., in 1969.


Fabricating a post and core to fit an existing crown.

This is a useful method for making a single post and core on an endodontically treated anterior tooth to fit an existing crown. It is a comparatively simple technique and gives a stable result.


Anencephaly and twins: prenatal ultrasound and estriol.

A rare case of anencephalic twin pregnancy diagnosed prenatally with ultrasonography is reported. It is the only case found in the literature in which maternal 24-hour urinary estriol is documented in an anencephalic twin pregnancy. Ultrasound diagnosis and obstetric problems associated with such cases are discussed briefly.


Ames test of 1-(X-phenyl)-3,3-dialkyltriazenes. A quantitative structure-activity study.

The mutagenicity of 1-(X-phenyl)-3,3-dialkyltriazenes was tested in the Ames test using Salmonella typhimurium TA92. The following quantitative structure-activity relationship (QSAR) was formulated: log 1/C = 1.09 log P -1.63 sigma+ + 5.58. In this expression, C is the molar concentration of triazene producing 30 mutations/10(8) bacteria above background. This equation is based on 17 congeners and has a correlation coefficient of 0.974. The QSAR for mutagenicity is compared with QSAR for antileukemia action and toxicity (LD50) in mice. The mutagenicity of aflatoxin B (log 1/C = 9.5) and DTIC (log 1/C = 3.0) have also been determined.


Synthesis and antibacterial activity of 2'-substituted chelocardin analogues.

Chelocardin (1) was condensed with numerous hydrazines, hydrazides, and anilines, yielding 2'-substituted derivatives with antibacterial spectra similar to the parent antibiotic. The hydrazone derivatives 9 and 10 and the two anilino derivatives 42 and 44 had more in vivo antibacterial activity than chelocardin.


Synthesis of all the stereoisomers of statine (4-amino-3-hydroxy-6-methylheptanoic acid). Inhibition of pepsin activity by N-carbobenzoxy-L-valyl-L-valyl-statine derived from the four stereoisomers.

Synthesis of all four stereoisomers of the novel amino acid statine, 4-amino-3-hydroxy-6-methylheptanoic acid, found in pepstatin, a potent acid protease inhibitor, has been accomplished. Carbobenzoxy-L-valyl-L-valyl-statine tripeptides derived from all four stereoisomers have been prepared and their effect on pepsin activity is compared to that of pepstatin.


Potential radiosensitizing agents. Dinitroimidazoles.

New compounds of the nitroimidazole series have been synthesized as radiosensitizers which selectively sensitize hypoxic cells to the lethal effect of radiation. The reaction of 2,4(5)-dinitroimidazole (2) with chloroethanol or hydrochloric acid yielded 4(5)-nitro-5(4)-chloroimidazole (3), which upon reaction with ethylene oxide yielded the 4-nitro-5-chloroimidazole-1-ethanol (6). Reaction of 2 with ethylene oxide resulted in a mixture of two compounds, the 2,4-dinitroimidazole-1-ethanol (4) and 2,3-dihydro-5-nitroimidazo[2,1-b]oxazole (5). The structure of the new heterocyclic compound 5 was confirmed by 1H NMR, mass spectrum, and X-ray crystallography. These agents were tested for their ability to sensitize hypoxic Escherichia coli cells to killing by ionizing radiation. Compound 4 was found to be the most active agent of this series of compounds.


Synthesis and biological activity of 5-fluoro- and 5-methyl-1,3-oxazine-2,6(3H)-dione.

5-Fluoro-1,3-oxazine-2,6(3H)-dione (3-oxa-FU) was synthesized by reacting 3-oxauracil with fluoroxytrifluoromethane and decomposing the adduct in the presence of a catalytic amount of Et3N. 5-Methyl-1,3-oxazine-2,6(3H)-dione (3-oxathymine) was prepared by polyphosphoric acid catalyzed ring closure of beta-(N-ethoxycarbonylamino)-2-methacrylic acid and by treatment of citraconimide with sodium hypochlorite. As determined in vitro, 3-oxa-FU was markedly inhibitory to S. faecium (ID50 = 9 X 10(-8) M) and E. coli (ID50 = 1 X 10(-7) M) but was less active against leukemia L-1210 cells (ID50 = 1 X 10(-5) M). At 1 x 10(-4) M, 3-oxathymine was inactive in these cell systems. Inhibition of the growth of S. faecium by 3-oxa-FU was reversed competitively by the natural pyrimidines. The relatively rapid hydrolysis of the compounds in the growth media is a major factor in determining their biological effectiveness.


Orally active esters of cephalosporin antibiotics. 3. Synthesis and biological properties of aminoacyloxymethyl esters of 7-[D(-)-mandelamido]-3-[[(1-methyl-1H-tetrazol-5-yl)thio]methyl]-3-cephem-4-carboxylic acid.

The synthesis of six amino acid acyloxymethyl esters of cefamandole (1), a semisynthetic broad-spectrum cephalosporin antibiotic, is described. These esters were examined as potentially useful orally active antibiotic prodrugs. When tested for oral efficacy against Streptococcus pyogenes C203 in mouse protection tests, the esters were not notably more active than lithium cefamandole. Further studies demonstrated that significant blood and urine levels of 1 were not obtained after dosing 2a, 2b, and 2f orally at 17 mg/kg in mice. A study of the stability to chemical hydrolysis and the possible relationship of hydrolysis to the lack of oral absorption of these esters is also presented.


Immunofluorescent skin band test in the differential diagnosis of systemic lupus erythematosus.

Forty-four uninvolved skin biopsies from lupus patients and 43 with various connective tissue diseases and nephritides other than lupus were tested for the presence of immunoglobulin deposition in the dermal-epidermal junction. Results were examined to determine their relationship to renal and clinical activity. Lupus band test (LBT) was positive in 30 (60%) SLE patients regardless of renal or clinical status. DNA-binding (p less than 0.01) and ANA (p less than 0.002) correlated to LBT. None of the other nephritides and only 2 with other connective tissue diseases were positive. LBT is a good aid in the differential diagnosis of SLE regardless of clinical or renal activity.


Germ-tube formation by oral strains of Candida tropicalis.

Candida species isolated from the mouths of healthy children and of patients with denture stomatitis included strains of Candida tropicalis that formed germ tubes when incubated in serum. Twenty-six germ-tube-forming strains of C. albicans and of C. tropicalis were subcultured weekly for 9 wk on blood agar and on Sabouraud's agar and the ability of each subculture to form germ tubes was measured. All the strains of C. albicans formed almost as many germ tubes after nine weekly subcultures as they did when first isolated. By contrast, although all 26 strains of C. tropicalis formed germ tubes when first isolated, all had lost the ability to do so after six serial weekly subcultures. Germ-tube formation should not be the sole criterion for the identification of oral C. albicans strains.


Serum creatine kinase levels in pubertal, mature, pregnant, and postmenopausal women.

In order to obtain control values for the diagnosis of carriers of Duchenne muscular dystrophy, creatine kinase (CK) estimations were performed in two laboratories on 148 healthy teenage girls (of whom 38 were premenarchal and 110 postmenarchal), 133 healthy mature women, 124 pregnant women, and 37 postmenopausal women. These levels were highest in the premenarchal teenagers, and became successively lower in the postmenarchal teenagers, the mature women, and the pregnant women, so that the mean level of the pregnant women was less than half that of the teenagers. The CK levels then rose again after the menopause. If the distribution of CK levels in adult non-pregnant women had been taken as controls for teenagers who were possible carriers for Duchenne muscular dystrophy, then one third of those teenagers classified as carriers would have been so classified incorrectly.


Measurement of Proteus cell motility during swarming.

The motilities of Proteus long forms during swarming on agar were measured on cells transferred to liquid suspension. During concentric-ring formation on solid medium, when the edge of the swarm was advancing slowly or had stopped, the velocity of long-form motility was low. When the colony was spreading rapidly, long-form velocitywas relatively high. This periodic variation in cell velocity, which determines the zones formed during swarming, cannot adequately be explained by negative chemotaxis.


Acquisition of Klebsiella aerogenes by neonates.

The acquisition of Klebsiella aerogenes by neonates born in hospital has been studied by sero- and klebecin typing. This organism was more commonly carried in the bowel of breast-fed babies than of bottle-fed babies. Only very rarely did babies acquire strains of K. aerogenes from their mothers. K. aerogenes was widely distributed in the ward environment and on the hands of nurses and mothers. Some strains were able to spread on the ward. These results are relevant to the control of K. aerogenes infection in maternity units.


The fimbrial and non-fimbrial haemagglutinins of Escherichia coli.

Both cultures of Escherichia coli were examined for mannose-sensitive (MS) haemagglutinin in rocked-tile tests with guinea-pig red cells at ambient temperature, and agar plate cultures were examined for mannose-resistant eluting (MRE) haemagglutinins against 14 species of red cells in tests mixed at 3--5 degrees C in the presence of .05% (w/v) D-mannose. Ox, sheep, human, pig, horse, guinea-pig, and fowl red cells were required to detect the various patterns of MRE haemagglutination with the different species of cells. Of 387 strains in 155 O serogroups, 95 formed both MS and MRE haemagglutinins (MS+/MRE+), 198 formed only MS (MS+/MRE-), 21 only MRE (MS+/MRE+), and 73 neither (MS-/MRE-). Strains of more than one of these types, and MRE+ strains with different cell specificities were found in many of the serogroups. Some strains in 144 O serogroups had MS haemagglutinin and some in 50 an MRE haemagglutinin. The presence of MS haemagglutinin in a culture was invariably associated with the presence of type-1 fimbriae on the bacteria. All MS+ strains shared a common antigen in their type-1 fimbriae and three groups of these strains possessed also a group-specific fimbrial antigen. The presence of certain kinds of MRE haemagglutinin in over half the MRE+ strains was associated with that of type-MRE fimbriae, but fimbriae were not detected in the other MRE+ strains. The antigens of the MRE haemagglutinins in different strains were heterogeneous and differed from those of the type-1 fimbriae of MS+ strains. Three series of strains from normal faeces, and from patients with infantile diarrhoea and urinary-tract infections each included a minority possessing neither type of haemagglutinin, but this observation did not preclude a role of the haemagglutinins in colonization or pathogenicity.


Effects of divalent cation ionophores on the neuron membrane of the crayfish.

The effects of divalent cation ionophores, A23187 and X-537A, on the electrical membrane properties were investigated by using the soma membrane of the X-organ of the crayfish. They reduced the amplitude and maximum rate of rise of Ca-action potential in lower concentration. As the concentration increased, a reduction of membrane resistance and hyperpolarization occurred simultaneously. Further increase resulted in membrane depolarization with a further decrease in resistance. The threshold concentration of X537A was 100 times higher than that of A23187. These effects were reversible only when the application period was relatively short, while a longer application resulted in an incomplete reversibility or in no reversibility at all. The ionophore effect was facilitated in high Ca medium and diminished in low Ca medium. In Sr medium, the same effects on the resistance and the membrane potential were barely observable. TEA reduced the effects of A23187 but did not completely inhibit the effects. The Na-cation potential was also reduced by the higher concentration of the ionophore. From these results it is concluded that the divalent cation ionophores. A23187 and X537A, carry divalent cations, Ca ions in a physiological medium, into the neuron soma through the membrane and the consequent increase of the intracellular divalent cations induces K conductance increase and that higher concentration of the ionophore induces the increase in the conductance of the other ion species, such as Na.


Radio-iodination of plasma membranes of toad bladder epithelium.

The present report describes high yield enzymatic radio-iodination of the apical and basal-lateral plasma membranes of toad bladder epithelium, by a procedure that does not breach the functional integrity of the epithelium, as assessed by the basal and vasopressin-sensitive short-circuit current (SCC). Restriction of the label to the membrane surface, was ascertained by light and electron-microscopic autoradiographs. On the apical surface, the grains were over the glycocalyx and the plasma membrane. Analysis of the labeled glycocalyx by agarose gel filtration, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), as well as enzymatic and pH-dependent hydrolysis indicated that the glycocalyx is a trichloro-acetic acid-soluble macromolecular complex of high molecular weight composed of a peptide moiety attached to large prosthetic groups (presumably carbohydrates) by O-glycosidic bonds. Analysis of the labeled apical plasma membrane components by agarose gel filtration and SDS-PAGE disclosed the presence of six major species of apparent molecular weights: 23,000, 28,000, 37,000, 44,000, 68,000, and 95,000. More than half of the membrane-associated radio-iodine was in two bands of molecular weights 37,000 and 44,000. Concentrations of vasopressin and cyclic AMP sufficient to increase the SCC significantly did not modify the extent of membrane labeling or the distribution of the label among the apical membrane components (presumably proteins) as assessed by SDS-PAGE. Iodination in the presence of amiloride inhibited incorporation but did not change the pattern of the distribution of the label among the components resolved by SDS-PAGE. Iodination of basal-lateral plasma membranes, at a yield comparable to that obtained with apical labeling, was attained after about 30 min of exposure of the intact bladder to the labeling solutions. Approximately 25% of the basal-lateral labeling was lost when the epithelial cells were harvested after collagenase treatment, implying that some iodination of the basement membrane had taken place. Less than 10% of iodination of the apical or basal-lateral surfaces was accounted for by lipid-labeling. Analysis of the labeled apical and basal-lateral species by enzymatic digestion and thin layer chromatography disclosed that virtually all the radioactivity was present as mono-iodotyrosine (MIT).


Cation permeation of the amphibian motor end-plate.

Measurements of acetylcholine-induced single-channel conductance and null potentials at the amphibian motor end-plate in solutions containing Na, K, Li and Cs ions (Gage & Van Helden, 1979; J. Physiol. (London) (in press) were analyzed in terms of three models. Two of these models, the "neutral" site channel model and the "charged" site channel model were developed to cater for three cations. Both were shown to be able to explain the dependence of single-channel conductance on membrane potential and gave the following sequences of equilibrium constants and mobilities. KLi/KNa/KK/KCs = 7:1.1:1:0.9 and UCs/UK/UNa/ULi = 1.4:1:0.58:0.13 at 8 degrees C. Similar sequences were obtained at 20 degrees C. Although the neutral model fitted the data for relative conductances in Li-, Cs- and Na-solutions slightly better than the charged model, experiments done in normal [NaCl] and [NaCl]/2 solutions could only be fitted by the neutral model. In contrast, the third model, the Constant Field Equation, was unable to fit the conductance data in any of the above situations. The data available suggests that permeation is through "long" neutral channels, lined with high field-strength negative polar groups and including one or possibly more high resistance barriers for anions.


Progression of fusion during rapid freezing for electron microscopy.

The method used to determine the rate of fusion was based on the large difference in the dielectric constants of water and ice. A thin (50--60 micrometers) slice of a gelatin gel was used as the dielectric in a plate condenser. The slice was placed on a metal electrode built in a specimen carrier which was dropped on a silver freezing surface kept at below 70 K, forming the other plate of the condenser. Freezing of the gelatin causes a marked decrease in a 20,000 cycle current passing through the condenser. Since the thickness of the layer of frozen material was shown to be a function of the reciprocal of the current, it was possible to determine the course of fusion of the section. Freezing started at a high rate which declined during the first 5 ms but then increased again and usually became quite high at the end of fusion.


A double embedding technique for the electron microscopic analysis of the liver acinus.

A double embedding technique allowing accurate and systematic sampling of zones of the hepatic acinus by electron microscopy was developed. The method involved the primary embedding of large (10 mm x 30 mm x 0.5 mm) liver slices and the preparation of 10 micrometers thick tissue sections by means of a rotary microtome with a steel knife. Veins 20--40 micrometers in diameter, the landmarks of the hepatic acinus, were localized by light microscopy, dissected from surrounding tissue and reembedded for ultramicrotomy. The method facilitated the systematic evaluation of hepatocyte ultrastructure in each zone of the microcirculatory unit of the liver, the hepatic acinus.


Achilles tendon repair with the plantaris tendon compared with repair using polyglycol threads.

Therapeutic results in 56 surgically treated patients with rupture of the Achilles tendon are presented. Results with repair using plantaris tendon and by suture of polyglycol threads are compared in 41 patients in a long-term followup study. Although 54 patients returned to their pre-accident physical activity, in all cases residual phenomena like calf atrophy, thickening of tendon, and tendon excursion were analyzed. The use of synthetic absorbable threads shortens the convalescence period. Covering the repair site with the fanned plantaris tendon seems to help to avoid painful adhesions with the skin.


Composite resection without mandibular reconstruction.

While composite resection remains the fundamental surgical approach to carcinoma of the posterior oral cavity, removal or reconstruction of the adjacent segment of mandible remains contentious. Various grafts have been used with less than satisfactory and unpredictable results. Bone has been brought in, borrowed, reshaped, and implanted into the area of mandibular deficit; mandibular osteotomy has been attempted with primary closure as well. A review of 78 composite resections at Upstate Medical Center reveals that of this number, 61 have undergone primary lateral mandibulectomy without reconstruction while four others have undergone more extended resection without reconstruction at the time of initial surgery. In the others, mandibular reconstruction has been unsatisfactory; mandibular osteotomy in the presence of irradiated tissue has been unsuccessful in all cases. In our experience, satisfactory results, functionally and cosmetically, have been attained with partial mandibulectomy and primary closure of the wound obviating more involved reconstructive procedures. A review of therapy with attention to surgical detail, complications, and results is presented.