Biomedical subjects
Publications and source records attributed to S J Nelson.
Dental clinicians should be aware that symptomatology of the head, neck, shoulders and arms, associated with cervical syndrome may present concurrent to temporomandibular disorders. A review of some cervical complex alterations is presented as well as treatment procedures which could reflect upon temporomandibular treatment in dentistry.
To investigate immuno-incompetence to polysaccharide Ag in young children, antibodies to the polysaccharide and protein Ag of Streptococcus pyogenes were studied. S. pyogenes was chosen because it commonly causes natural infections and has well-characterized polysaccharide and protein Ag. In children over the age of 2 yr it was found that the maturation of antibody responses to the polysaccharide Ag of S. pyogenes (A-CHO) appeared to occur in parallel with, or even earlier, than the responses to streptococcal protein Ag. When antibodies to group A carbohydrate (A-CHO) were studied in detail, qualitative differences between the antibodies of children and adults were demonstrated. Although anti-A-CHO antibodies of adults were strikingly restricted to the IgG2 subclass, those of children were found in both the IgG1 and IgG2 subclasses. In addition, the clonal diversity of IgG antibodies to A-CHO increased with age, and additional clonotypes were detectable in convalescent sera of some subjects of all ages after infection. Two cases with major additional clonotypes after group A streptococcal infection were studied in detail. In these two cases the additional clonotypes belonged to a different IgG subclass than the previously dominant clonotypes, and the expression of the additional major clonotypes occurred in both IgG1 and IgG2 subclasses.
Eight human subjects measured peak integrals from a set of simulated 31P NMR spectra by triangulation, by extrapolation of tangents from the baseline of computed integrals, and by cursor demarcation of computed integrals using standard commercial software. The test spectra were qualitatively similar to phosphorus spectra routinely acquired from mammalian skeletal muscle. All three of the above methods were found to underestimate the areas of relatively broad peaks (e.g., ATP peaks were underestimated by 20-40%), even when the peak signal/rms-noise ratio was better than 8/1. This bias resulted in major errors in calculated metabolite ratios. Of the three methods, triangulation was the least accurate, and showed the greatest variation between subjects. Cursor demarcation of computed integrals was the most accurate manual method. The same test spectra were also integrated by two fully-automated fitting algorithms. Although not free of bias, these methods were generally superior to the manual methods.
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The polysaccharide (PS) capsule of Haemophilus influenzae type b (Hib) is a "simple" antigen, polyribosylribitolphosphate. Although similar carbohydrate antigens have been reported to elicit IgG antibodies relatively restricted to the IgG2 subclass in man, we report here that Hib PS elicits substantial quantities of both IgG1 and IgG2 serum antibodies in most individuals. Because the determination of IgG subclass distribution can be technically difficult, we used four different approaches to establish our finding. First, we used an IgG subclass-specific, antigen-specific "sandwich assay." Second, we measured IgG subclasses of purified antibodies to Hib PS. Third, we showed that significant amounts of IgG anti-PS can be absorbed with a monoclonal anti-IgG1 affinity column. Fourth, we showed that IgG1 and IgG2 fractions of immune sera have clonally restricted anti-Hib PS antibodies that are easily distinguishable by their isoelectric points. The data indicate that both IgG1 and IgG2 contribute substantially to the IgG antibody response of most adults to immunization with Hib PS.
A baseline model for consideration of the theoretical effects of amniotic fluid volume changes on surfactant concentration measurements has been constructed. The baseline data include: a polynomial equation that best fits experimental data comparing amniotic fluid lecithin concentration measurements to gestational age, inflow of 0.450 L of surfactant-poor fluid into the amniotic fluid per day, outflow of 0.450 L of surfactant-rich fluid per day, and volume of 1.0 L of amniotic fluid between 30 to 31 and 38 to 39 weeks' gestation. With this model the incremental amounts of lecithin necessary to achieve the concentration levels derived from the polynomial equation have been calculated. The quantity of lecithin needed was calculated at intervals of 0.1 day for 56 days. Polyhydramnios and oligohydramnios were then allowed to develop hypothetically by modifying the inflow or outflow of fluid while keeping the quantity of lecithin added exactly the same as was determined from the baseline data. Chronic polyhydramnios or oligohydramnios had minimal effects on the concentration measurements. The effects of acute polyhydramnios (or oligohydramnios) were greater when the change in volume was due to an increased (or decreased) volume of inflow as compared to a decreased (or increased) volume of outflow.
Children less than 24 months of age respond poorly to immunization with the capsular polysaccharide of Haemophilus influenzae type b. Because human antibodies to polysaccharide antigens are relatively restricted to IgG2, a late-maturing subclass, we examined the relationship between serum subclass concentrations and anticapsular antibody responses of 41 healthy children, 9 to 38 months of age, following immunization with type b polysaccharide mixed with pertussis vaccine. Both total and IgG anticapsular antibody responses correlated significantly with preimmune serum concentrations of IgG2 but not with those if IgG1. This correlation was age dependent, however, and after the effect of age was removed by partial correlation, the correlation between anticapsular antibody responses and serum IgG2 concentrations was no longer significant. These findings indicate that the ability to respond to this vaccine coincides with maturation of the ability to secrete immunoglobulin of the IgG2 subclass; however, individual variation in IgG2 that is independent of age does not correlate with antibody response to the type b polysaccharide.
RECONSIDER, a computer program designed to perform as a diagnostic prompting aid, was evaluated for its ability to include the correct diagnosis in an ordered computed list of candidate diseases. The study was performed using 100 consecutive first admissions to the medical service of a university hospital, where the individuals entering the data into the program were blind to all but a limited set of findings known at time of admission. Each person entering the data created one or more lists of diagnostic possibilities (versions) using the program. The program suggested the correct diagnosis within the first 40 on its list 61% (498/797) of the time; the correct diagnosis was present with the first 40 in at least one version 93% (98/105) of the time. Performance was found to be best with cases having a single diagnosis and when more terms were entered into the program.
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Concentrations of IgG1, IgG2, and total IgG were measured by a solid phase radioimmunoassay in sera from 36 healthy adults and 114 healthy children. As expected, IgG2 and total IgG had a positive correlation with age in children. In addition to age, several other factors were associated with significant differences in serum subclass concentrations. Female children had higher concentrations of IgG1 than males, and black subjects had significantly higher concentrations of IgG1, IgG2, and total IgG than whites. Although Km(1) and Gm(23) immunoglobulin allotypes had no relation to subclass concentrations when tested as single factors, the Km(1) allotype interacted significantly with race so that Km(1)-positive black children had higher IgG2 concentrations than other subjects. Our findings may explain, in part, recent observations of an association of the Km(1) allotype with altered immune responses of blacks to certain vaccines containing bacterial polysaccharides. In addition, our data indicate the need to control factors such as sex, race, and allotype in studies of subclass concentrations or immune responses.
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The effects of competitive inhibitors of transglutaminase on the formation of myotubes by the fusion of myoblasts in vitro has been investigated. Myotube formation was inhibited when myoblasts from 11-day-old chick embryos were cultured in vitro in the presence of 10 mM histamine or 0.2 mM dansyl cadaverine. The inhibitions observed were reversed when the treated cells were subsequently cultured in normal medium. Glycine methyl ester also inhibited myotube formation but sarcosine methyl ester, which is not a competitive inhibitor of transglutaminase, had little if any inhibitory action. The formation of myotubes was not inhibited by cultivation in normal medium adjusted to pH 8.0-8.1, indicating that the observed effects of histamine and of dansyl cadaverine were not mediated by a lysosomotropic effect. Inhibition of myotube formation in the presence of histamine was accompanied by the production of abnormal multinucleated cells, indicating that myoblast fusion occurred in the treated cultures but that the fused cells failed to elongate into normal myotubes. Transglutaminase activity has been found in cell-free lysates of embryonic chick myoblasts and it is concluded that a transglutaminase enzyme, activated by an increase in the concentration of intracellular Ca2+, plays an important role in stabilising the cytoskeletal network of developing myotubes.
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Scrotal masses are a common problem in children. Cystic lesions usually are found to be hydroceles, while solid masses suggest the possibility of neoplasia. A rare cause of a cystic scrotal mass is ectasia of the rete testis. A review of the literature reveals only 1 case similar to the patient herein described. Both patients had agenesis of the ipsilateral kidney, which explained on the basis of the embryologic overlapping of the genitourinary system. Our patient bears clinical similarity to the ACI rat and correlation is made with this animal model system. Excision of the multiloculated rete testis cyst, rather than orchiectomy, appears to be curative.
Salmonellosis in older children and adults is usually a self-limited disease, but the risk of complications in infants is not well-defined. We performed a retrospective review of 52 patients. 90 days of age or less, seen at the St. Louis Children's Hospital between 1975 and 1981 with stool cultures positive for salmonella. Sixteen were 30 days old or less (neonates), 21 were 31- 60 days of age, and 15 were 61-90 days old. Among patients in whom blood cultures were done initially, bacteremia was most frequent in neonates: 5/11 (45%), compared to 2/18 (11%) in older infants. All seven infants presenting with bacteremia received 10 or more days of antibiotic therapy: yet complications (osteomyelitis, fatal meningitis or chronic diarrhea) developed in three of five neonates and one of two older infants. Complications also developed in seven of 22 patients who initially had negative blood cultures, including two infants in whom sepsis later developed and two infants who required intravenous hyperalimentation because of chronic diarrhea and malnutrition. The group of 23 patients who did not have blood cultures all did well. Salmonellosis is not necessarily a self-limited infection in young infants. Even in the absence of bacteremia, clinicans would appear to be justified in using antimicrobial therapy in infants 3 months of age or les with salmonella gastroenteritis, particularly neonates of older infants with symptoms of dysentery or failure to thrive.
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A simple method of analytical subcellular fractionation, combined with a sensitive computational method for data analysis and presentation, has been used to reinvestigate the distribution and relative amounts of several enzymes in the cytoplasmic and plasma membranes of two different cell types: one is a neoplastic, transformed cell type (Ehrlich ascites tumour cells), the other an untransformed, highly differentiated cell type (liver hepatocytes plus Kupffer and endothelial cells). In general the distribution of the enzymes in particular membranes is similar in the two cell types, however the relative amounts differ. Ehrlich ascites tumour cells have a higher specific activity of galactosyltransferase and ouabain-sensitive (Na,K)ATPase, while liver cells have higher glucose-6-phosphatase, 5'-nucleotidase and succinate dehydrogenase activity. These differences appear to be correlated with morphological and, in some cases, functional differences between the two cell types.