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Biomedical subjects

A Roberts

Publications and source records attributed to A Roberts.

At least 415 records · Page 23Linked to original sources
PubMedDate not supplied

The effect of saccharin on the microbial metabolism of tryptophan in man.

The microbial catabolism of tryptophan to indole has been studied in 15 human subjects by analysis of the daily urinary excretion of indican (potassium indoxylsulphate) before, during and after chronic saccharin ingestion. The daily excretion of indican during a 3-wk control period showed marked inter- and intra-subject variability. Analysis of the urinary excretion of saccharin during chronic administration demonstrated good compliance for both saccharin ingestion and urine collection. The urinary excretion of indican was not increased significantly by the ingestion of saccharin (1 g/day as divided doses with meals) for one month. These findings are consistent with epidemiology studies which show the absence of a consistent excess risk of cancer of the urinary bladder in humans ingesting saccharin as a food additive.

Adult↗
PubMedDate not supplied

Paraneoplastic myasthenic syndrome IgG inhibits 45Ca2+ flux in a human small cell carcinoma line.

Certain cancers exert unexplained remote effects on the nervous system. Small cell carcinoma (SCC) of the lung, a tumour capable of spike electrogenesis and which is of possible neural crest origin, is present in approximately 70% of patients with the Lambert-Eaton myasthenic syndrome (LEMS), a disorder characterized by fatigable muscle weakness. Patients with this syndrome have a defect in the (Ca2+-dependent) quantal release of acetylcholine from motor nerve terminals evoked by a nerve impulse or by high K+ (ref.5), and a decreased number of presynaptic active zone particles. The physiological and morphological features of the syndrome can be transferred to mice by the patients' IgG, consistent with an autoantibody interfering with the function of voltage-dependent Ca2+ channels. Here we demonstrate that K+-induced 45Ca2+ flux in a cultured human SCC line is significantly reduced by LEMS IgG, suggesting that in SCC-LEMS an autoantibody to tumour Ca2+-channel determinants is triggered; its cross-reaction with similar determinants at the motor nerve terminal could lead to the remote neurological syndrome.

Antibody Specificity↗
PubMedDate not supplied

Inhibitory neurones of a motor pattern generator in Xenopus revealed by antibodies to glycine.

Glycine and gamma-aminobutyric acid (GABA) are inhibitory transmitters of major importance. Whereas neurones using GABA as the transmitter can be visualized by immunocytochemical methods for glutamate decarboxylase (GAD) or GABA, no comparable techniques have been available for the selective visualization of glycinergic neurones. We have now produced polyclonal antibodies which specifically recognize glycine in glutaraldehyde-fixed tissue. We used these antibodies to investigate the distribution of glycine in the simple central nervous system (CNS) of the Xenopus embryo, which contains an anatomically and physiologically defined class of reciprocal inhibitory interneurones, the commissural interneurones. These interneurones have an important role in the generation of the swimming motor pattern and are thought to be glycinergic. The glycine antibodies specifically stain these interneurones, revealing their distribution and number in the embryo CNS. This is the first demonstration of the selective localization of glycine-like immunoreactivity in a putative glycinergic class of neurone that has been characterized physiologically, pharmacologically and anatomically.

Animals↗
PubMedDate not supplied

Comparison of fetal lung maturation in preterm singleton and twin pregnancies.

Preterm labor or premature rupture of membranes is one of the major complications of twin pregnancies and contributes to the increased maternal and perinatal morbidity and mortality. Forty-seven twin pregnancies and a comparable group of singleton pregnancies constitute the study population. These patients' pregnancies were complicated only by preterm labor. The lecithin to sphingomyelin ratio is used as an index of fetal lung maturation. Analysis of the data reveals that fetal lung maturation is biochemically comparable between twin and singleton pregnancies and among twins for a given gestational age in this clinical setting.

Adult↗
PubMedDate not supplied

A scoring system for the quantitative evaluation of oral mucositis during bone marrow transplantation.

A system for assessing the severity of mucositis in patients undergoing bone marrow transplantation (BMT) is presented. Ten criteria were graded to give component scores together with a total score. The overall severity score ranged from 0 through 21. Scores were assigned three times daily by nursing staff members and verified daily by the attending dental and medical practitioners. Total scores were highly reproducible and were related to the severity of neutropenia. Variation between sequential total scores was not related to interexaminer variation but rather to changes in the severity of oral mucositis. Component scores provided a useful means for transmitting oral health information between health care personnel. Total scores were used to regulate the nature and frequency of oral hygiene procedures for patients undergoing BMT as well as other hematology/oncology patients. Application of this oral assessment system to other institutional settings may be beneficial.

Adolescent↗
PubMedDate not supplied

Fetal and maternal white cells and B- and T-lymphocyte subpopulations in pregnant women with recent infection.

OBJECTIVE: To study maternal and fetal white cell counts, B- and T-lymphocyte subpopulations in pregnant women with evidence of recent infection. METHODS: Thirty-seven pregnant women with recent infection and 38 controls were studied. All were referred for fetal blood sampling to exclude congenital infection, or to perform fetal chromosome analysis. There were 16 infected fetuses: 9 cytomegalovirus (CMV), 4 rubella, and 3 toxoplasmosis. Maternal and fetal blood was taken and white cell counts, the percentage of CD3+, CD4+, CD8+, CD56+, HLADR+CD3+ T-lymphocyte subpopulations and CD19+ B lymphocytes were measured. RESULTS: The percentage of CD3+, CD8+, and HLADR+CD3+ lymphocytes were significantly higher in infected mothers compared to controls, while CD19+ and the CD4+/CD8+ ratio were lower. Infected mothers carrying infected fetuses had significantly lower white blood cell counts compared to those infected mothers without fetal infection. The percentage of HLADR+CD3+ T lymphocytes was significantly higher and the CD4+/CD8+ ratio lower in infected fetuses compared to controls and noninfected fetuses of infected mothers. Abnormal CD4+/CD8+ ratios and/or increased HLADR+CT3+ T lymphocytes were found in 8 of 10 fetuses with structural abnormalities and/or hematological/biochemical signs of systemic damage, and in 7 of 27 without (RR = 3.1, 95% CI = 1.5-6.3). CONCLUSION: Both infected fetuses and their mothers have significant identifiable changes in white cell counts and T-lymphocyte subpopulations compared to controls. These tests may help in diagnosing maternal and fetal infection.

B-Lymphocytes↗
PubMedDate not supplied

Fetal growth and birthweight in isoimmunized pregnancies after intravenous intrauterine transfusion.

Forty-seven fetuses treated with intravenous intrauterine transfusion for rhesus isoimmunization were studied. At the time of first transfusion the fetuses were below average in size with the fetal femur length being directly related to the degree of fetal anemia. Subsequent to transfusion therapy there was increased growth of all fetal parameters measured. Birthweight was similar to a control group of unaffected fetuses. This contrasts with results after intraperitoneal transfusion where birthweights have been reported as being below average.

Birth Weight↗
PubMedDate not supplied

Plasma phosphatidylcholine/free cholesterol ratio as an indicator for atherosclerosis.

Plasma lipid profiles were determined in two inbred strains of mice, C57BR/cdJ and CBA/J, fed either a normal chow or an atherogenic diet for a 15-week period, starting at 10 weeks of age. On the chow diet, the C57BR/cdJ had significantly higher mean free cholesterol, esterified cholesterol, and total lipid values, and a significantly lower mean phosphatidylcholine/free cholesterol ratio than the CBA/J mice. On the atherogenic diet, the C57BR/cdJ had significantly higher mean levels for all lipids classes, except triacylglycerols, than the CBA/J mice. The mean plasma free cholesterol and esterified cholesterol levels of the C57BR/cdJ were four times greater than those of the CBA/J strain on the atherogenic diet. The mean plasma phosphatidylcholine/free cholesterol ratio of the C57BR/cdJ mice on the high cholesterol diet was 0.87 compared to 1.91 for CBA/J mice. These plasma lipid changes were associated with a marked development of atheromatous deposits in the wall of the aortic sinus of the C57BR/cdJ compared to the CBA/J animals. The phosphatidylcholine/free cholesterol ratios of the liver lipids of both strains decreased from 2.5-2.7 on the chow diet to 1.0-1.1 on the high cholesterol diet. It is suggested that a plasma phosphatidylcholine/free cholesterol ratio less than 1 represents a supersaturation of the vascular system and the vessel wall with cholesterol, which leads to a destabilization of the plasma membranes of the endothelial and smooth muscle cells, and an infiltration of the vessel wall by the plasma lipids.

Animals↗
PubMedDate not supplied

Lipoprotein levels in genetically selected mice with increased susceptibility to atherosclerosis.

Male mice of two inbred strains, C57BR/cdJ and CBA/J, were maintained either on an atherogenic diet rich in cholesterol (5%) and saturated fat (30%) or on a control Purina Laboratory Chow diet. After 3 weeks on a 90% atherogenic/10% chow diet, the C57BR/cdJ mice showed a fivefold increase in plasma total cholesterol levels, while the CBA/J strain indicated only a twofold increase. On the atherogenic diet, both groups of animals showed marked increases in a lipoprotein of a broad density spectrum (1.006 greater than d less than 1.063) with prebeta and beta mobility on agarose gel electrophoresis, but the C57BR/cdJ strain showed a greater increase than the CBA/J strain. The very low density lipoprotein (VLDL) contained predominantly lipoprotein of prebeta mobility, while intermediate density lipoprotein (IDL) and low density lipoprotein (LDL) contained lipoprotein of beta-mobility. In both strains, the major lipid component in this lipoprotein was cholesteryl ester and both strains showed large amounts of an apoprotein (apo) with E mobility as defined for known apoproteins by sodium dodecyl sulfate polyacrylamide gel electrophoresis or by isoelectric focusing on polyacrylamide-urea disc gels. The phosphatidylcholine/free cholesterol ratio of the VLDL, IDL, and LDL fractions isolated from the C57BR/cdJ mice on the atherogenic diet (0.76 to 0.95) was noticeably lower than that (1.10 to 1.19) from the CBA/J mice maintained on the same diet. There was a marked decrease in the high density lipoprotein (HDL) fraction in both strains of mice on the atherogenic diet, but a greater reduction in the HDL level of the C57BR/cdJ strain with a 50% decrease in the phosphatidylcholine/free cholesterol ratio.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMedDate not supplied

A correlation between shoulder laxity and interfering pain in competitive swimmers.

Shoulder pain in the swimming athlete that interferes with effective training is serious and may result in decreased performance. Based on the hypothesis that shoulder laxity is an important factor in shoulder pain, this study of 40 senior national and elite swimmers was undertaken. A questionnaire identified those athletes currently suffering from such pain. Shoulder laxity was assessed using standard clinical tests, from which a laxity score was derived. A statistically significant correlation was identified between the shoulder laxity score and the presence of interfering shoulder pain, confirming the hypothesis of the study. These results have direct implications for training the symptomatic athlete.

Adolescent↗