Biomedical subjects
Publications and source records attributed to S Carr.
Parents' perceptions of temperament in their three-month-old infants were examined in relation to prenatally measured parental characteristics and to objective indices of infant behavior at three months. Infant behavior and parental characteristics appear to make independent contributions to parents' perceptions in early infancy.
Anticholinergic effects of the 25 drugs most commonly prescribed for the elderly were measured by radioreceptor assay. Fourteen had detectable anticholinergic drug levels; 10 of these had levels that have been associated with impairments in memory and attention in normal elderly subjects. These data indicate that patients taking multiple medications may be at increased risk for side effects from psychotropic drugs, most of which have anticholinergic effects.
Increased sodium-lithium countertransport in erythrocytes is found in patients with insulin-dependent diabetes mellitus (IDDM) and nephropathy. To determine whether such an increase precedes the onset of nephropathy and, if so, whether it is associated with changes in renal function, we measured erythrocyte sodium-lithium countertransport in 52 patients with IDDM but not nephropathy or hypertension and in 32 control subjects. Seventeen of the 52 patients with IDDM (33 percent) had sodium-lithium countertransport activity that exceeded the maximal activity in the control subjects (0.39 mmol of lithium per hour per liter of cells). Eighteen of the 52 patients with IDDM were studied in more detail. The 7 patients with raised sodium-lithium countertransport values had glomerular filtration rates (median, 159 ml per minute per 1.73 m2 of body-surface area; range, 134 to 197) that were significantly higher (P less than 0.01) than those in the remaining 11 patients with IDDM and normal sodium-lithium countertransport (median, 126 ml per minute per 1.73 m2; range, 110 to 176) or in the 10 control subjects (median, 128 ml per minute per 1.73 m2; range, 93 to 151). In the seven patients with elevated sodium-lithium countertransport, the filtration fraction (median, 0.27; range, 0.22 to 0.37) was also greater (P less than 0.01) than that in control subjects (median, 0.22; range, 0.18 to 0.28). There were no differences in renal function between the patients with IDDM and normal sodium-lithium countertransport and the control subjects. We conclude that sodium-lithium countertransport is increased in patients with IDDM before the onset of nephropathy and is associated with hyperfiltration. Thus, elevated sodium-lithium countertransport activity may be an early marker of diabetic nephropathy.
A young woman with long-standing systemic lupus erythematosus and rheumatic fever presented with deteriorating renal function. She had severe gastritis treated with cimetidine and received methylprednisolone when her blood cultures were repeatedly negative. She developed spontaneous bruising and bleeding from venepuncture sites, leading to clotting studies and a diagnosis of thrombotic thrombocytopenic purpura. At post-mortem, extensive evidence of disseminated zygomycosis was found. The likely portal of entry was the gastric route.
1. Escherichia coli heat-stable enterotoxin (ST) induces a secretory diarrhea by binding to receptors on brush borders of intestinal villus cells, activating particulate guanylate cyclase and increasing intracellular concentrations of guanosine 3',5'-cyclic monophosphate (cyclic GMP). 2. However, little is known concerning coupling of receptor-ligand interaction to enzyme activation. 3. This study compares the kinetics of toxin-receptor binding and enzyme activation to better understand this transmembrane signal cascade. 4. Toxin receptor binding was linear and saturable with 50% of maximum displacement of [125I]ST by unlabeled toxin observed at 1.1 x 10(-7) M. ST increased the maximum velocity (Vmax) of guanylate cyclase with magnesium or manganese as the cation substrate without altering the affinity of the enzyme for its substrate or its positive cooperativity. 5. The concentration of toxin yielding half-maximum stimulation of guanylate cyclase was 1.2 x 10(-6) M, 10-fold higher than the affinity of the ligand for its receptor. 6. These data are consistent with the suggestion that ST-receptor interaction is coupled to activation of particulate guanylate cyclase. 7. However, the discrepancy between the affinity of ST for its receptor and its efficacy in activating the enzyme suggests that this coupling is complex. 8. Possible mechanisms underlying this coupling are discussed.
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Trichotillomania is seen in normal children with a variety of psychiatric conditions (Krishnan, 1985). Although an association between depression and trichotillomania has been suggested in adults and adolescents (Krishnan, 1985), its association with DSM-III-R major depressive disorder in a prepubertal child has not been reported. Such a case of trichotillomania occurring with major depressive disorder is reported in this paper. In this prepubertal child, imipramine therapy led to remission of both disorders.
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The use of reflectance meters to screen for gestational diabetes has been advocated because of convenience and apparent accuracy. The present study addresses the possibility that imprecision of reflectance meters may affect the reliability of the blood sugar values obtained with their use. We tested four reflectance meters (Glucometer, Glucometer II, Glucoscan 3000, and Accuchek II) on 84 gravidas undergoing 1-hour, 50-g glucose screening, and calculated average coefficients of variation (9.6 +/- 10.9, 8.2 +/- 4.7, 6.8 +/- 4.5, and 7.4 +/- 4.4%, respectively). One-way analysis of variance testing indicated no significant difference between these values (P = .11). However, comparison with the coefficients of variation from standard laboratory technology (YSI Model 23A Glucose Analyzer) applied to simultaneously obtained venous samples (2.3 +/- 1.5, 1.5 +/- 0.6, 1.9 +/- 1.0, and 1.0 +/- 0.5%) revealed that the meters all had coefficients of variation significantly higher (P less than .0001). Use of reflectance meters would have resulted in 45.2% (38 of 84) of the subjects undergoing 3-hour oral glucose tolerance tests. Use of standard laboratory values would have indicated these tests in only 16% (14 of 84). The inconvenience and increased cost of these oral glucose tolerance tests suggest that meters may not be appropriate for screening.
A cell line derived from a human ovarian carcinosarcoma was established in tissue culture and in nude mice. Two sublines, LDF and HDF, separated by discontinuous density centrifugation were also established from the parent line JoN. The cloning efficiency of the JoN line was 21%. Morphologic features of adenocarcinoma cells characteristic of the parent JoN cells were retained in the sublines and clones; all lines showed the same karyotype and DNA content (pseudodiploid and pseudotetraploid). Keratin, as demonstrated immunohistochemically, was strongly expressed in the parent line JoN and the xenograft tumor, but not at all in the LDF sublines and only moderately in the HDF sublines. Vimentin, however, was expressed in neither the parent line JoN nor the xenograft tumor, but was present in both sublines. Transglutaminase and plasminogen activator activity was high in the parent line JoN. Neither, sublines nor clones showed the same high enzyme activity as the parent line. It is concluded that this human tumor line JoN is comprised of epithelial cells, capable of multidirectional differentiation.
Sodium-lithium countertransport is believed to depend on a specific protein and since such proteins usually decline with erythrocyte age it would be expected to be reduced in older cells. In fact, sodium-lithium countertransport increased with ageing, whereas the rate constant of the sodium pump decreased. The increase in sodium-lithium countertransport with erythrocyte ageing was due to a phloretin insensitive component that was not present in young erythrocytes. Raised sodium-lithium countertransport in patients with essential hypertension was due mainly to an increased phloretin sensitive component but the phloretin insensitive component was also higher in middle aged erythrocytes. Amiloride had no effect upon sodium-lithium countertransport or unidirectional sodium influx in cells of any age. This suggests that sodium-lithium countertransport is not a mode of action of the sodium-proton exchanger in the erythrocyte.
A method has been developed that allows for the detection of the eleven stereoisomers of diphenylcyclobutanedicarboxylic acid in illicit cocaine samples, including alpha-, gamma-, and epsilon-truxillic acids and beta- and delta-truxinic acids. These, and other carboxylic acids, were also detected as ester moieties of alkaloidal impurities in illicit cocaine as well as in alkaloids of the South American coca leaf, e.g., alpha- and beta-truxilline. After lithium aluminum hydride reduction of the acidic and basic extracts of a prepared sample, the reduced species were derivatized with heptafluorobutyric anhydride in the presence of pyridine. The heptafluorobutyryl derivatives of the reduced diphenylcyclobutanedicarboxylic compounds were easily detected on-column at low picogram levels using a moderately polar fused-silica capillary column in the splitless mode and interfaced with a 63Ni electron-capture detector.
Five years experience in the application of electron microscopy to fine needle aspiration biopsy specimens is reviewed. In an initial evaluation, 200 consecutive unselected specimens were examined; 89 proved diagnostic and, in a third of these, electron microscopy gave additional information that was often essential to diagnosis. Negative specimens resulted almost entirely from failure to obtain an adequate amount of material. Results were improved by the adoption of a preparation technique involving concentration of the cells in bovine serum albumin and by the inspection of a rapidly stained smear at the time of the aspiration procedure, with a further needle pass for electron microscopy being performed if necessary. Despite the small size of specimens, adequate examination was usually possible and electron microscopy has proved of value in the diagnosis of tumor samples acquired by fine needle aspiration in the same way as has been established with the larger sized specimens obtained by conventional biopsy and surgical resection.
In Caenorhabditis elegans collagens comprise a dispersed family of 40-150 genes, the majority of which probably code for collagen proteins found in the animal's cuticle. The conserved (Gly-X-Y)n triple helix coding sequence of collagen genes has facilitated the isolation of a large number of C. elegans collagen genes by recombinant DNA methods. We have begun a study of the chromosomal organization of these genes by screening laboratory strains of C. elegans for DNA polymorphisms in the regions surrounding collagen genes. Polymorphisms near seven genes have been identified and have been used as phenotypic markers in genetic crosses to assign the genes to linkage groups II, III, IV, and X. Four genes are shown by multifactor crosses to map to a 2-3 map unit interval between unc-24 and unc-22 on chromosome IV.
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Explore the source record for details and available documents.