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Biomedical subjects

J A Carter

Publications and source records attributed to J A Carter.

72 records · Page 4Linked to original sources
PubMed1978

Bile acid conjugation in the chimpanzee: effective sulfation of lithocholic acid.

To characterize the hepatic biotransformation in the chimpanzee of the primary bile acid chenodeoxycholic acid (chenic) and its major bacterial metabolite lithocholic acid (lithocholic) a mixture of trace amounts of 14C-lithocholic and 3H-chenic was injected intravenously into two animals with a bile fistula; the chemical form of radioactivity appearing in bile was inferred using thin layer chromatography. About 80% of chenic, and 70% of lithocholic was recovered in 90 min. Chenic was completely conjugated in bile, appearing predominantly as chenyltaurine (52%) and chenylglycine (37%). An unidentified conjugate (about 11%) was also found. Lithocholic was excreted completely as taurine and glycine conjugates, but the majority (63%) of conjugates was sulfated. Sulfation increased progressively with time, and lithocholylglycine was sulfated more than lithocholyltaurine. We conclude that the chimpanzee is similar to man in that the secondary bile acid lithocholic is efficiently sulfated. The chimpanzee thus differs from the baboon and rhesus monkey which sulfate lithocholic poorly. However, the chimpanzee differs from man and is similar to the baboon and rhesus monkey in showing preferential conjugation of bile acids with taurine. The results imply that hepatotoxicity caused by chenic, which is well documented in the rhesus monkey and baboon and has been related to defective lithocholic sulfation, should not occur in the chimpanzee.

Animals↗
PubMed1978

Distribution of gamma-aminobutyric acid, glycine, glutamate and aspartate in the cochlear nucleus of the rat.

The distributions of gamma-aminobutyric acid (GABA), glycine, glutamate and aspartate were measured in cochlear nuclei of two rats by quantitative histochemical mapping procedures. The levels and distributions in the two rats were comparable, and resembled those previously reported for cat cochlear nucleus. The results are consistent with a concept that these putative transmitter amino acids have similar levels and distributions in the cochlear nucleus among mammals.

Aminobutyrates↗
PubMed1978

Field independence and performance on ball-handling tasks.

Subjects were administered the Children's Embedded Figures Test and four ball-handling tests. Pearson product-moment correlations were low between the measures. Girls scored significantly higher than boys on the embedded figures test while boys scored significantly higher than girls on the striking and throwing tests.

Child↗
PubMed1977

Radioimmunoassay of unsulfated lithocholates.

A simple, rapid, precise radioimmunoassay for total unsulfate species of lithocholate (lithocholyglycine, lithocholyltaurine, and lithocholate) in serum is described. Antiserum was raised in rabbits by injection of lithocholylglycine coupled to bovine serum albumin (prepared by a carbodiimide method) and emulsified in complete Freund's adjuvant; antisera capable of measuring 40-120 pmol at 1:400 dilution were obtained. The tracer was [11, 12-3[H]lithocholyglycine. The radioimmunoassay featured a 2-hr binding step at 42 decrease C and a 1-hr separation step using polyethylene glycol. The antibody had the following relative specificities: lithocholyglycine and lithocholytaurine, 1; lithocholate, 1.5; chenodeoxycholyglycine, 20; and deoxycholylglycine, 55. There was no binding of various other free or conjugated sulfated and unsulfated bile acids. The mean fasting-state level in 50 healthy subjects was 0.3 mu mol/l (0.14 microgram/ml), but 11 of the 50 subjects had level too low to measure by this technique.

Antibody Specificity↗
PubMed1977

Radioimmunoassay of sulfated lithocholates.

A sensitive, rapid radioimmunoassay for sulfated species of lithocholic acid (sulfolithocholyglycine, sulfolithocholyltaurine, and sulfolithocholic acid) was developed and used to measure the total concentration of sulfated lithocholates in serum from healthy human subjects. Sulfolithocholylglycine was conjugated to bovine serum albumin by a carbodiimide procedure, and the reaction product, emulsified in Freund's adjuvant, was injected into rabbits. The antiserum obtained was capable to binding 40% of [3H]sulfolithocholylglycine at 1:1000 dilution. The assay featured a 2-hr binding step at 42 degrees C followed by precipitation of bound tracer with polyethylene glycol at 4 degrees C. The assay can be used with 0.1 ml of serum and was reproducible. The antibody had little affinity for the 3-sulfate of cholic or chenodeoxycholic acid, a number of steroid sulfates, or unsulfated bile acids. In 50 healthy subjects, mean (+/-SE) fasting-state serum levels of immunoreactive sulfated lithocholyl conjugates (+sulfated lithocholate) was 1.6 +/- 0.1 micrometer; based on results with a separate radioimmunoassay for unsulfated lithocholyl conjugates, most of the lithocholate in serum in healthy man is present in sulfated form.

Antibody Specificity↗
PubMed1976

Lithocholate metabolism during chenotherapy for gallstone dissolution. 1. Serum levels of sulphated and unsulphated lithocholates.

Serum levels of total sulphated and total unsulphated lithocholates were each measured by a specific radioimmunoassay in 66 patients ingesting chenodeoxycholic (chenic) acid for gallstone dissoultion and in 35 gallstone patients ingesting either cholic acid or placebo. No changes occurred in serum lithocholate levels in the control groups. In patients ingesting chenic acid, there was a twofold increase in serum levels of total lithocholate, but the percent sulphation (greater than 75%) remained unchanged during chenotherapy. There was no correlation in the chenic acid treated group between serum lithocholate levels and the proportion of lithocholate in biliary bile acids or changes in serum SGOT. The data suggest that there is effective sulphation of lithocholate in such patients; this may explain the lack of hepatotoxicity observed during ingestion of chenic acid.

Aspartate Aminotransferases↗
PubMedDate not supplied

Triton WR-1339, a lysosomotropic compound, is excreted into bile and alters the biliary excretion of lysosomal enzymes and lipids.

In these experiments, we tested two hypothesis: first, that Triton WR-1339, a nonionic detergent which is sequestered in hepatocyte lysosomes, undergoes biliary excretion; and second, that Triton WR-1339, which also alters serum lipid levels and modifies hepatic catabolism of lipoproteins, affects the biliary output of proteins and lipids. When 3H-Triton WR-1339 was administered to rats, biochemical and morphologic studies showed that hepatocyte lysosomes sequestered Triton WR-1339: (i) the subcellular distribution of 3H was identical to that of lysosomal enzymes after liver fractionation by differential or isopycnic centrifugation, and (ii) lysosomes appeared engorged with Triton WR-1339 on electron microscopy. 3H was also excreted into bile in parallel to three lysosomal enzymes. Triton WR-1339 administration caused a coordinate increase in the biliary excretion of three lysosomal enzymes and also increased the biliary output of total protein, bile acids, and phospholipid. Triton WR-1339 administration did not affect bile flow or the biliary outputs of cholesterol, plasma membrane, and cytosolic enzymes, but did decrease biliary cholesterol saturation by 50%. These results demonstrate that an exogenous compound which is sequestered in hepatocyte lysosomes may be excreted directly into bile in parallel with endogenous lysosomal constituents. The data also show that such a lysosomotropic agent may also selectively modify the biliary excretion of proteins and lipids. The findings are consistent with the existence of a lysosome-to-bile hepatic excretory pathway and suggest that hepatocyte lysosomes may be important in modulating biliary protein and lipid secretion.

Acetylglucosaminidase↗
PubMedDate not supplied

Evaluation of a treatment-appropriate cognitive intervention for challenging alcohol outcome expectancies.

The current study evaluated an alcohol expectancy challenge (EC) that did not require alcohol administration and could therefore be implemented in a treatment setting. Participants in the treatment group directly challenged alcohol expectancies endorsed on an expectancy questionnaire. A total of 62 male and female undergraduates completed the study (32 control participants, 30 EC participants). Self-report questionnaires were collected pre- and post-intervention, and alcohol logs were kept during the study. The EC resulted in significant reductions in alcohol expectancies across multiple expectancy dimensions. Although the analysis for alcohol consumption was not significant, there was a trend toward better outcomes for male participants in the EC condition. In contrast to study hypotheses, women in the EC condition increased their alcohol consumption from pre to post-test to a greater degree than did control participants.

Alcohol Drinking↗
PubMedDate not supplied

Self-esteem, gender, and alcohol use: relationships with HIV risk perception and behaviors in college students.

The present study examined the confluence of alcohol use and self-esteem on risky sexual behavior and perceptions of risk for female and male college students. It was predicted that higher levels of self-esteem, female gender, and lower alcohol consumption would be associated with greater condom use and lower perceptions of risk for self and partner. Results indicated that for low drinking students, those with high self-esteem reported greater condom use. In addition, low rates of alcohol use were associated with greater frequency of past condom use. Women and students low in self-esteem indicated greater perceptions of risk for themselves and their partners. These findings are discussed in terms of their implications for developing interventions aimed at reducing risky sexual behavior.

Adolescent↗
PubMedDate not supplied

Gender differences related to heterosexual condom use: the influence of negotiation styles.

The present study had three primary goals. The first was to identify gender differences related to negotiation styles associated with condom use. We hypothesized that women would report engaging in more negotiation behaviors associated with condom use than men. The second goal was to determine whether the relationships between intentions to use condoms and past condom use for women and men were moderated by negotiation behaviors. The third goal was to examine gender differences in responses to an open-ended question inquiring why participants did not use condoms. Male and female college students (N = 219) anonymously completed a series of measures. The results indicated that women and men have unique roles in the negotiation process; women play a more active role in negotiation of condom use, while men play a more reactive role. The relationship between intentions to use condoms and past condom use increased for men when their partners were more active in the process of deciding whether to use condoms. Responses to the open-ended item revealed that women identified perceptions of low risk as the most common reason for not using condoms, while men identified the inconvenience or unavailability of condoms as the most common reason. The implications of these results are discussed as they relate to health efforts to increase condom use.

Adolescent↗
PubMedDate not supplied

Validity and reliability of the 'Ten Questions' questionnaire for detecting moderate to severe neurological impairment in children aged 6-9 years in rural Kenya.

BACKGROUND: The 'Ten Questions' Questionnaire (TQQ) is used to detect severe neurological impairment in children living in resource-poor countries. Its usefulness has been established in Asia and the Caribbean, but there are a few published studies from Africa. We evaluated the TQQ as part of a larger study of neurological impairment in a rural community, on the coast of Kenya. METHODS: The study was conducted in two phases from June 2001 to May 2002; in phase one, a community household screening of 10,218 children aged 6-9 years using the TQQ was performed. Phase two involved a comprehensive clinical and psychological assessment of all children testing positive on the TQQ (n = 810) and an equivalent number of those testing negative (n = 766). Data were interpreted using the impairment-specific approach. RESULTS: Overall, the sensitivity rates for screening the different impairments were: cognitive (70.0%), motor (71.4%), epilepsy (100%), hearing (87.4%) and visual (77.8%). All the specificity rates were greater than 96%. However, the positive predictive values were low, and ranged from 11 to 33%. CONCLUSIONS: These results are similar to those from other continents and provide evidence that the TQQ can be used to compare the epidemiology of moderate/severe impairment in different parts of the world. Furthermore, the TQQ can be used to screen for moderately/severely impaired children in resource-poor countries; however, the low positive predictive values mean that other assessments are required for confirmation.

Child↗