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Biomedical subjects

J Jones

Publications and source records attributed to J Jones.

At least 559 records · Page 31Linked to original sources
PubMed1989

Early and late passage C-6 glial cell growth: similarities with primary glial cells in culture.

Earlier studies in our laboratory have shown that C-6 glial cells in culture exhibit astrocytic properties with increasing cell passage. In this study, we tested the responsiveness of early and late passage C-6 glial cells to various cultures conditions: culture substrata (collagen, poly-L-lysine, plastic), or supplements for the culture medium, DMEM, [fetal calf, or heat inactivated (HI) serum, or media conditioned from mouse neuroblastoma cells (NBCM) or primary chick embryo cultured neurons (NCM)]. Glutamine synthetase (GS) and cyclic nucleotide phosphohydrolase (CNP), astrocytic and oligodendrocytic glial markers, were used. Cell number and protein content increased exponentially with days in culture regardless of the type of the substratum or cell passage. Differences in cell morphology among the three types of substratum were also reflected on GS activity, which rose by three-fold on culture day 3 for cells grown on collagen; thereafter, GS profiles were similar for all substrata. This early rise in GS is interpreted to reflect differential cell adhesion processes on the substrata; specifically, cell adhesion on the collagen stimulated differentiation into "astrocytic phenotype". Analogous to immature glia cells in primary cultures, early passage C-6 glial cells responded to neuronal factors supplied either from NCM or NBCM by expressing reduced GS activity, the astrocytic marker and enhanced CNP activity, the oligodendrocytic marker. Thus, early passage cells can be induced to express either astrocytic or oligodendrocytic phenotype. In accordance with our previous reports on primary glial cells, late passage C-6 cells exhibit their usual astrocytic behavior, responding to serum factors with GS activity. Moreover, whereas NCM or NBCM alone markedly lowered GS activity, a combination with serum restored activity. The present findings confirm our previous observations and further establish the C-6 glial cells as a reliable model to study immature glia.

Animals↗
PubMed1989

A study of inter-reviewer reliability of attacks recorded on ambulatory EEG.

Eleven ambulatory EEG (A/EEG) cassette tapes were sent to 5 reviewers from different EEG laboratories in the U.K. Each tape included one attack recorded from a different patient. Attacks were chosen to include various possible EEG changes that can occur during attacks on A/EEG. Reviewers were asked to give details of EEG changes seen during attacks and to state whether they thought attacks were epileptic. Total agreement about the presence of abnormality was found on 2 tapes. Four out of 5 reviewers agreed on 4 tapes and on the remaining 5 tapes only 2 or 3 reviewers were in agreement. It was concluded that the amount of agreement amongst reviewers was poor but reasonable in view of the degree of difficulty of the tapes which were not a random sample. Compared to the final clinical opinion of referring consultants, these findings would have resulted in 16% false negatives, 7% false positives and 13% of cases in which no decision was made.

Ambulatory Care↗
PubMed1989

Prognostic significance of eosinophils and mast cells in rectal cancer: findings from the National Surgical Adjuvant Breast and Bowel Project (protocol R-01).

The numbers of eosinophils and mast cells observed at the tumor border of 331 rectal cancers from patients enrolled in the National Surgical Adjuvant Breast and Bowel Project (NSABP), protocol R-01, were correlated according to overall survival rate, as well as Dukes' stage, tumor differentiation, nodal status, degree of lymphoid and stromal reactions, sex, and age. Life table plots disclosed a significantly better overall survival rate when ten or more eosinophils per 30 oil immersion fields were found. However, the numbers of eosinophils were strongly associated with Dukes' stage and, when life table plots were adjusted for Dukes' stage, this relationship to survival rate was not evident. On the other hand, overall survival rate was significantly higher in patients in whom 0 to three mast cells per 30 oil immersion fields were found than in those patients in whom four or more mast cells were found. This relationship persisted even when life table plots were adjusted for treatment, Dukes' stage, or nodal status, and indicated that the number of mast cells further defined survival rate among patients exhibiting Dukes' A, B, and C stages. It is concluded that numbers of eosinophils and mast cells may play a role in the natural history of rectal cancer but only the latter represents a prognostic parameter independent of Dukes' stage or nodal status. The mechanism whereby mast cells may exert this effect is at present unknown.

Cell Count↗
PubMed1989

X-inactivation of the Sts locus in the mouse: an anomaly of the dosage compensation mechanism.

The behaviour of the X- and Y-borne Sts locus has been studied in male and female mice. There was considerable heterogeneity in STS activity between inbred mouse strains, with a four fold difference in activity between the highest (101/H) and lowest (Ju/Ct) activity strains, which can be interpreted in terms of allelic differences. In all inbred strains male STS levels were higher than those of female STS levels and in the majority of strains tested male STS levels were nearly twice as high as female levels. Reciprocal crosses between C3H/HeH and the STS-deficient substrain, C3H/An, demonstrated that activities of the X- and Y-borne genes in males are essentially the same and this suggested that the lower STS level in females derives from X-inactivation of the locus. The possibility that hormonal differences could instead be responsible for the lower activity in females was ruled out by the findings that (a) castration of males did not reduce their STS levels and (b) sex-reversed males, X/X Sxr, had STS levels typical of females. Final proof that the mouse Sts locus can be subject to the X-inactivation process was provided by the observation that XX females had STS levels that were only slightly (20%) higher than those of XO females. The difference may indicate incomplete inactivation of the locus. Linkage data verifying the location of Sts on the distal end of the X chromosome are provided.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Hormones regulating lipid and carbohydrate metabolism in premenopausal women: modulation by dietary lipids.

The effect of high- and low-fat diets with different levels of fatty acid unsaturation on plasma hormones involved in lipid metabolism was studied during different phases of the menstrual cycle in 31 premenopausal women. Subjects were divided into two groups and were fed controlled diets containing 39% fat with a ratio of polyunsaturated to saturated fatty acids (P:S) of either 0.3 or 1.0 for four menstrual cycles and then switched to a 19% fat diet with the same P:S for another four cycles. Blood samples were analyzed during both the follicular and luteal phases. A significant direct effect of level of dietary fat was observed on plasma cortisol and dehydroepiandrosterone-sulphate whereas an inverse relationship was seen for plasma insulin. Both plasma insulin and growth hormone levels were higher during the luteal compared with the follicular phase of the menstrual cycle. None of the hormones was affected by the level of unsaturation of dietary fats.

Adult↗
PubMed1989

Dietary fat and menstrual-cycle effects on the erythrocyte ghost insulin receptor in premenopausal women.

The effect of high- and low-fat diets with different levels of fatty acid unsaturation on insulin receptors of erythrocyte ghosts was studied during different phases of the menstrual cycle in 31 healthy premenopausal women. Subjects were divided into two groups and consumed controlled diets containing 39% fat with a ratio of polyunsaturated to saturated fatty acids (P:S) of either 0.30 or 1.00 for four menstrual cycles. They were switched to 19% fat at the same P:S for another four cycles. Fasting blood samples were collected during the follicular and luteal phases. Insulin receptors were measured from right-side-out ghosts. Insulin binding was significantly lower due to fewer receptors when subjects were fed the low-fat, high-carbohydrate diet compared with the high-fat, low-carbohydrate diet. There was no significant effect of level of unsaturation or time of menstrual cycle on insulin binding. Thus, insulin receptors on erythrocytes respond to dietary lipids.

Dietary Fats↗
PubMed1989

Practical evaluation of trauma deaths.

The TRISS method of auditing trauma deaths necessitates audit of patients with minor injuries who die of their underlying medical problems. Using an anatomic definition of injury as a criterion for audit, as suggested by Wesson et al. at the Hospital for Sick Children in Toronto, excludes patients with minor injuries but necessitates audit of patients who expired due to systems problems rather than in-hospital patient care. We propose combining the TRISS and Toronto methods in order to identify the deaths truly appropriate for detailed review of hospital care. Fifty-four trauma deaths over a 22-month period were audited and categorized as frankly preventable, potentially salvageable, or nonpreventable. Considering only in-hospital care, the deaths designated as potentially salvageable by audit were likely to be identified by both TRISS and Toronto, while deaths targeted by only one system were more likely to be nonpreventable by audit. The predictive value of this combination of methods (84.6%) was better than Toronto (52.4%) or TRISS (54.5%) using audit results as the standard for comparison. This simple computerized method may serve as a practical and inexpensive method of targeting deaths for in-depth review.

Adolescent↗
PubMed1989

Cohort and case-control analyses of workers exposed to vinyl chloride: an update.

The mortality in a cohort of workers at a vinyl chloride polymerization plant has been updated, extending the period of observation in the original study from 1974 to 1986. Workers at this plant may have been exposed to vinyl chloride monomer and/or polyvinyl chloride dust, or may have had no exposure to either substance. Seventy-six percent of the work force worked in jobs with potential exposure to vinyl chloride monomer. Among the total cohort, statistically significant excess risks were observed for liver, lung, and brain cancer. For the subcohort of workers exposed to vinyl chloride monomer, the standardized mortality ratio (SMR) for liver cancer was 333 (90% confidence interval (CI) 202 to 521). However, there were no significant excesses of either brain (SMR = 145, 90% CI 78 to 249) or lung cancer (SMR = 115, 90% CI 96 to 141). To investigate dose response, nested case-control studies for liver, brain, and lung cancer were conducted among the total cohort (including the nonexposed). For these studies there were two exposure variables, cumulative dose of vinyl chloride monomer and cumulative dose of polyvinyl chloride dust. Cumulative dose was defined as the product of level and duration of exposure. The only significant association between disease risk and cumulative dose was for liver cancer and cumulative dose of vinyl chloride monomer. Further division of the liver cancers into angiosarcoma (n = 12) and other liver cancers (n = 7), based on review of death certificates and medical records, showed that the dose response existed only for angiosarcomas.

Brain Neoplasms↗
PubMed1989

The diagnosis of polycystic ovaries in subfertile women.

Laparoscopy was used to identify the polycystic ovary (PCO) in a group of subfertile women. A third were found to have PCO. These patients had higher levels of luteinizing hormone (LH), testosterone (T) and a higher free androgen index (FAI) than those with normal ovaries. Only 15% of patients with laparoscopic evidence of PCO were obese, hirsute and oligomenorrhoeic. Within the PCO group, hirsutism was strongly associated with obesity and a high FAI. A group of subfertile women with PCO and regular cycles was found who had no other identifiable cause for their infertility. These women had higher follicular phase concentrations of LH and higher FAI than ovulatory women with normal ovaries.

Adult↗
PubMed1989

Insulin-like growth factor 1 as an intra-ovarian hormone--an integrated hypothesis and review.

Fourteen ovulatory patients undergoing diagnostic laparoscopy had at least 2 samples of clear follicular fluid (FF) collected in the late follicular phase. Dominant follicles contained significantly higher concentrations of insulin-like growth factor-1 (IGF1), oestradiol (E2), progesterone (P) and lower androstenedione (AD) than their matched cohorts. After the luteinizing hormone (LH) surge, a significant increase in dominant FF-IGF1 and FF-P occurred. Log FF-E2 and log FF-P were correlated with both FF-IGF1 and FF volume. Log FF-AD was negatively correlated with FF-volume, FF-E2 and FF-P (but not FF-IGF1). The cohort concentration of FF-IGF1 was correlated with serum IGF1. These results support the hypothesis that IGF1 has a central role in the selection of the dominant follicle.

Adult↗
PubMed1989

Advances in catheter ablation use of unipolar electrograms.

Ventricular tachycardia in man can be eliminated by relatively small lesions in the reentrant circuit. This report includes a review of available energy sources, and methods for localizing arrhythmias. Methods to assure contact and prevent perforation using low frequency electrograms are presented including the new finding of reverse ST deflection with contact. Experience with laser energy in dogs showed discrete homogenous lesions. When compared with DC shock the animals showed far less arrhythmia and the lack of far field effect greatly reduced echo abnormalities in the post shock period. Studies with radiofrequency show ability to produce localized lesions similar to the laser but with a more flexible catheter. Localization requires a correlation of techniques including pacemapping, activation maps and pacing during tachycardia. Early activation (less than -60 ms) at times 180-320 ms, with comparable pace to QRS during tachycardia with no change in morphology best localized the slow zone of the reentrant circuit. The low frequency unipolar electrogram from the tip and immediately proximal electrode revealed contact with ST deviation. The distal deviation was always greater than the proximal RV free wall and posterior basal produced depression rather than elevation of the electrogram. While the mechanism of ST reversal with contact is not understood and may relate to the type of indifferent reference used (Wilson central terminal), the ST depression reveals the same information about contact that elevation does in most areas of the heart studied in our patients.

Animals↗
PubMed1989

Physiological growth hormone secretion and response to growth hormone treatment in children with short stature and intrauterine growth retardation.

Physiological growth hormone (GH) secretion was examined in 31 children (8 girls, 23 boys) with short stature secondary to intrauterine growth retardation (IUGR). Seventeen (4 girls, 13 boys) had dysmorphic features of Russell-Silver syndrome. Four of the 31 children had GH insufficiency with peak GH levels of less than 20 mU/l during the night. Nine of the patients (8 of whom had Russell-Silver syndrome) had a single nocturnal GH pulse. Twenty-three children (6 girls, 17 boys) were randomized into two groups treated with either 15 or 30 U/m2/week of GH by daily subcutaneous injections. Age, sex distribution, pretreatment height velocity SD score (SDS), and distribution of dysmorphic and non-dysmorphic children were similar in both groups. The group treated with 15 U/m2/week for a mean of 0.82 years showed an increase in mean height velocity SDS from -0.61 to +1.09, and the group treated with 30 U/m2/week for a mean of 0.92 years showed an increase in mean height velocity SDS from -0.69 to +3.48. The results suggest that physiological GH insufficiency is probably common in children with Russell-Silver syndrome and that both dysmorphic and non-dysmorphic children with short stature secondary to IUGR will respond to GH treatment. Initial evidence suggests that the increase in short-term growth velocity does not result in an improved final height prognosis.

Body Height↗
PubMed1989

Growth of South African Indian schoolchildren in different social classes.

The height and weight of 4594 Indian schoolchildren aged 6 to 17 years, in Durban, South Africa, were measured at schools selected by inspectors as representative of upper, intermediate, and lower socio-economic populations. Significant superiority, anthropometrically, prevailed at all ages in upper compared with lower or poor-class children, but tended to lessen at 17 years. In the affluent group, in the age period studied the proportions under the 5th percentile of USA NCHS reference values were--concerning height-for-age 4.7% to 22.0% of boys and 5.0% to 20.7% of girls; and concerning weight-for-age, 20.3% to 45.0% of boys and 9.3% to 37.7% of girls. In the affluent group, at full growth at 17 years, means of height and weight were highly significantly lower, namely, roughly by 7cm and 10kg, compared with respective mean values given in USA reference values. Hence, in Indian schoolchildren a genetic factor, and not dietary inadequacy, appears primarily responsible for both slower post-pubertal growth and lower ultimate height attainment.

Adolescent↗
PubMed1989

Effect of dietary carbohydrates on insulin and glucagon receptors in a new model of noninsulin-dependent diabetes-SHR/N-corpulent rat.

A new congenic strain of rat, the SHR/N-corpulent, provides a good model for noninsulin-dependent diabetes and was used in the present study. Corpulent rats as compared to their lean littermates are obese, hyperlipidemic, and severely hyperinsulinemic, and show an age-dependent loss of glucose tolerance. Mild fasting hyperglycemia is seen only in corpulent rats fed sucrose. Since dietary sucrose is more lipogenic than starch and since insulin and glucagon are involved in lipid and carbohydrate metabolism, we studied the effect of the type of dietary carbohydrate on insulin and glucagon levels and their receptors in lean and corpulent SHR/N rats. A significant phenotypic effect was observed (corpulent greater than lean) on plasma levels of triglyceride, cholesterol, and insulin. Dietary sucrose increased these parameters in corpulent rats but not in lean rats. Insulin and glucagon binding to liver plasma membranes was lower in corpulent rats than in lean; decreases were due to fewer receptors without a significant change in affinity. Thus, in corpulent rats, in addition to hyperinsulinemia, fewer glucagon receptors and their failure to be regulated by plasma glucagon levels appear to contribute to the hyperlipidemia. Furthermore, the hyperglycemia observed in sucrose-fed corpulent rats may be due to extreme resistance to insulin despite lower plasma glucagon and fewer glucagon receptors.

Animals↗
PubMed1989

The effect of clomiphene citrate on follicular phase increase in endometrial thickness and uterine volume.

Fifteen ovulating women had serial ultrasound scans to measure follicular, endometrial, and uterine growth, as well as biochemical indices including estradiol (E2) and the free androgen index, throughout a natural and a clomiphene-citrate-induced cycle. Despite higher E2 levels in the 5 days preceding ovulation, the clomiphene cycles were characterized by absence of the normal increase in uterine volume and an inhibition of endometrial thickening. It is proposed that the anti-estrogen effect of clomiphene inhibits the normal cyclical growth of the uterus and endometrium.

Adult↗