Association between confined placental trisomy, fetal uniparental disomy, and early intrauterine growth retardation.
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Female↗
Biomedical subjects
P Bennett
Publications and source records attributed to P Bennett.
Caldesmon binds to smooth muscle myosin and myosin rod and crosslinks thick filaments to actin filaments.
It is well established that caldesmon binds to actin (Kb = 10(7) - 10(-8) M-1) and to tropomyosin (Kb = 10(6) M-1) and that it is a potent inhibitor of actomyosin ATPase. Caldesmon can also bind tightly to myosin. We investigated the binding of smooth muscle and nonmuscle caldesmon isoforms (CDh and CDl respectively) to myosin using proteins from sheep aorta. Both caldesmon isoforms bind to myosin with indistinguishable affinity. The affinity is about 10(6) M-1 in low salt buffer, but is weakened by increasing [KCl] reaching 10(5) M-1 in 100 mM KCl. The stoichiometry of binding is about three caldesmon per myosin molecule. Stoichiometry and affinity are not dependent on whether myosin is phosphorylated nor on the presence of Mg2+ and ATP, provided the ionic strength is maintained constant. The caldesmon binding site of smooth muscle myosin is located in the S-2 region, consequently both HMM and myosin rod bind to caldesmon. Over a range of conditions myosin and myosin rod binding to caldesmon were indistinguishable. Skeletal muscle myosin has no caldesmon binding site. Smooth muscle myosin rods form side-polar filaments in low salt buffer in which the backbone packing of LMM into the filament shaft is clearly visible in negatively-stained electron microscopic images. Sometimes the S-2 portions can be seen 'frayed' from the filament shaft. When caldesmon is bound the filament shaft appears to be about 20% thicker and the frayed effect is dramatically increased; long filamentous 'whiskers' are often seen curving out from the filament shaft. Similar structures are observed with smooth muscle and with non-muscle caldesmon. Myosin also binds to caldesmon when it is incorporated into the thin filament; however, this interaction is qualitatively different. Measurements of smooth muscle HMM binding to native thin filaments in the presence of 3 mM MgATP shows there is a high affinity binding (Kb = 10(6) M-1) which is independent of [Ca2+] and of the level of myosin phosphorylation. The stoichiometry is one HMM molecule per actin monomer which is equivalent to up to 14 HMM bound at high affinity per caldesmon. Negatively stained electron microscopic images of the HMM.ADP.Pi-thin filament complex have failed to show any attachment of HMM to the thin filaments. When rod filaments are added to actin plus caldesmon or to native thin filaments the rod filaments are strongly associated with the actin filament bundles. The majority of rod filaments are lined up parallel and in close proximity to actin filaments.(ABSTRACT TRUNCATED AT 400 WORDS)
Actin Cytoskeleton↗
Determination of twin zygosity by DNA hybridisation to wild type bacteriophage M13.
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Bacteriophage M13↗
Characterization of the chromosomal aac(6')-Ic gene from Serratia marcescens.
The DNA sequence of the chromosomal aac(6')-Ic gene from Serratia marcescens, which had been previously cloned (H. M. Champion, P. M. Bennett, D. A. Lewis, and D. S. Reeves, J. Antimicrob. Chemother. 22:587-596, 1988) was determined. High-pressure liquid chromatographic analysis of extracts prepared from Escherichia coli carrying the chromosomal aac(6')-Ic gene on a plasmid confirmed the presence of 6'-N-acetyltransferase activity in this strain, which was suggested by the aminoglycoside resistance profile. DNA sequence analysis of the cloned 2,057-bp PstI fragment revealed several regions of homology to previously characterized sequences from GenBank, including the rpoD and tRNA-2 genes of E. coli. Subcloning experiments confirmed the coding sequence of the aac(6')-Ic gene to be at positions 1554 to 1992. The predicted amino acid sequence of the AAC(6')-Ic protein suggested that it was the third member of a family of AAC(6') proteins which included a coding region identified between the aadB and aadA genes of Tn4000 and an AAC(6') protein encoded by pUO490, which was isolated from Enterobacter cloacae. Primer extension analysis suggested that the -35 region of the aac(6')-Ic promoter overlapped a large palindromic sequence which may be involved in the regulation of the aac(6')-Ic gene. Hybridization experiments utilizing a restriction fragment from the aac(6')-Ic gene showed that all S. marcescens organisms carried this gene whether or not the AAC(6')-I resistance profile was expressed. Organisms other than Serratia spp. did not hybridize to this probe.
Base Sequence↗
The contribution of body composition, substrates, and hormones to the variability in energy expenditure and substrate utilization in premenopausal women.
Twenty-four-hour energy expenditure and substrate use were measured by indirect calorimetry in respiration chambers on a fixed physical program and related to body composition and plasma concentrations of various substrates and thermogenic hormones. Fifty premenopausal women with a wide range of body weight were examined in the follicular menstrual phase under weight stable conditions. Most of the variance in the sleeping energy expenditure (82%) was accounted for by two covariates, lean body mass (75%, P less than 0.0001), and fat mass (7%, P less than 0.0001). An additional 6% of the variance in sleeping energy expenditure was accounted for by plasma androstenedione concentration (4%, P = 0.0005) and by free T3 index (2%, P = 0.03). Thus physiological variation among individuals in plasma androstenedione concentration may result in a difference in energy expenditure of 908 kJ/day and the corresponding variation in free T3 index may result in a difference between individuals of 594 kJ/day. Fifty four percent of the variation in carbohydrate oxidation rates was accounted for by 24-h energy balance, and by plasma concentrations of insulin, nonesterified fatty acids, and estradiol. Waist circumference, plasma nonesterified fatty acids, and estradiol concentrations explained 49% of the variance in 24-h lipid oxidation. An obese subgroup of women (n = 27) had significantly higher 24-h energy expenditure, lipid, and carbohydrate oxidation rates than an age-matched normal weight group (n = 16), but the entire group difference in energy expenditure was explained by differences in body composition. We conclude that physiological variations in plasma androstenedione and T3 concentrations contribute to the interindividual variance in energy expenditure of women, and their role is not different in obese women. A positive energy balance and increased insulin action may be mediators of the higher carbohydrate oxidation in obesity, whereas an increased substrate availability seems to bring about the increased lipid oxidation.
Adolescent↗
The pituitary-gonadal axis in women with benign or malignant ovarian tumors.
The serum levels of follicle-stimulating hormone (FSH), luteinizing hormone (LH), human chorionic gonadotropin (hCG), estradiol, progesterone, androstenedione, testosterone (total and free) and dehydroepiandrosterone sulphate (DHEAS) were investigated prior to surgery in 24 postmenopausal women with benign and 28 postmenopausal women with malignant epithelial ovarian tumors. The serum concentrations of hormones were compared with those of 28 healthy, postmenopausal, age-matched controls. Significantly lower serum FSH levels were demonstrated in women with malignant tumors. No significant differences were found between the groups regarding the serum LH levels. The hCG levels were low in all groups. Regarding progesterone and estradiol levels, low postmenopausal steroid levels were found in all groups examined and no significant differences were demonstrated within the groups. No significant correlations between the levels of estradiol and FSH or progesterone and LH were demonstrated. To exclude a central depression of gonadotropin release mediated by the dopaminergic system we examined the thyroid stimulating hormone (TSH) and prolactin. No differences were found between the groups regarding TSH and prolactin levels. A possible relationship between other hormones/factors produced by the tumor and exerting a negative feedback, either centrally or directly, on the gonadotropin release remains to be investigated. A change in biological activity in the gonadotropins might explain the present findings.
Aged↗
Serum sex hormones and endurance performance after a lacto-ovo vegetarian and a mixed diet.
Serum sex hormones and endurance performance after a lacto-ovo vegetarian and a mixed diet. Med. Sci. Sports Exerc., Vol. 24, No. 11, pp. 1290-1297, 1992. The effect of a lacto-ovo vegetarian (V) and a mixed, meat-rich (M) diet on the level of serum sex hormones, gonadotropins, and endurance performance of eight male endurance athletes was investigated in a 2 x 6 wk cross-over study. The energy contribution from carbohydrate, fat, and protein was 58%, 27%, and 15% on the V diet and 58%, 28%, and 14 E% on the M diet. For total fasting serum testosterone (T) there was a significant interaction between diet and time (P < 0.01). Thus, the V diet resulted in a lower total T level (13.7, 9.8-32.4 nmol.l-1) (median and range) compared with the M diet (17.4, 11.8-33.5 nmol.l-1). During exercise after 6 wk on the diets total T was also significantly lower on the V than on the M diet (P < 0.05). Serum free testosterone, however, did not differ significantly during the 6 wk dietary intervention periods and neither did serum concentrations of sex hormone binding globulin, dihydrotestosterone, dehydroepiandrosterone sulphate, 4-androstenedione, estrone, estradiol, estrone sulphate, or gonadotropins. Endurance performance time was higher for six and lower for two after the mixed diet compared with the vegetarian diet. This was not significant, however. In conclusion, 6 wk on a lacto-ovo vegetarian diet caused a minor decrease in total testosterone and no significant changes in physical performance in male endurance athletes compared with 6 wk on a mixed, meatrich diet.
Diet↗
Testis cancer. Ichthyosis constitutes a significant risk factor.
Testis cancer and ichthyosis are both relatively rare diseases. Hence the finding of six individuals with both these conditions in a small population with testicular cancer is highly conspicuous and indicates some kind of connection among such persons. Despite the identical clinical appearances of their ichthyoses, three of the ichthyotic subjects had no measurable activity of the enzyme, steroid sulfatase (STS) in leucocytes, a distinct characteristic of recessive X-linked ichthyosis (RXLI). However, the remaining three subjects had normal STS activity, a strong indicator of autosomal dominant ichthyosis (ADI). The STS activity in patients with testicular cancer who do not have ichthyosis (N = 30) was also within the normal range. The patients with testicular cancer with no skin disease had elevated serum levels of 4-androstenedione (4-AD), follicle stimulating hormone (FSH), and luteinizing hormone (LH) but had reduced levels of estrone and estrone sulfate. The other serum parameters measured did not significantly differ from normal levels. In essence, the hormone levels obtained for the patients with ichthyotic testicular cancer followed the same pattern, although their dehydroepiandrosterone sulfate (DHEAS) and estrone sulfate levels tended to be slightly higher than normal. However, no conspicuous aberrations in any of the parameters examined were observed, and why men with ichthyosis are at high risk for testicular cancer remains an unresolved issue.
Adult↗
Treating Type A behaviours and mild hypertension in middle-aged men.
Unmedicated mildly hypertensive Type A men were randomly allocated to one of three conditions: stress management intervention training (N = 15), Type A management (N = 15), and delayed Type A management intervention. Significantly greater reductions in blood pressure at rest and during the Type A structured interview were found following the active interventions than during the minimal treatment control period of the delayed intervention. Type A management was more successful in changing a number of Type A behaviours, including anger, hostility and global Type A behaviour. Changes on measures of anger-in, -out, hostility, and SI ratings of Type A behaviour were associated with changes in systolic and diastolic blood pressure reactivity during interview.
Adult↗
Menopausal age and sex hormones in postmenopausal women with alcoholic and non-alcoholic liver disease.
In order to evaluate age at menopause and serum sex hormone profiles in postmenopausal women with stable chronic liver disease, six non-cirrhotic alcoholics, 13 with alcoholic cirrhosis, eight with non-alcoholic cirrhosis, and 46 healthy controls were studied. In all three groups, patients were significantly (p less than 0.05) younger at the time of natural menopause than controls. Compared to controls, non-cirrhotic alcoholic women had significantly (p less than 0.05) reduced levels of DHAS, significantly (p less than 0.05) more alcoholic cirrhotic women had detectable oestradiol concentrations, elevated concentrations of oestrone and sex hormone binding globulin (SHBG) and reduced levels of 5 alpha-dihydrotestosterone (DHT), while women with non-alcoholic cirrhosis had significantly elevated concentrations of SHBG and reduced levels of oestrone sulphate, DHT, androstenedione and dehydroepiandrosterone sulphate (DHAS) (p less than 0.05). The observed changes may be a consequence of liver disease since similar changes were observed in patients with alcoholic and non-alcoholic liver disease, but an additional effect of alcohol cannot be excluded.
Aged↗
Patterns of drinking in Wales.
As part of a larger survey of health-related behaviours, 8441 Welsh men and women aged 18-64 years provided information relating to their overall consumption of alcohol, frequency of binge drinking (defined as consumption of at least half the recommended weekly limits, less than or equal to 21 units for men, less than or equal to 14 units for women) per occasion, and changes in consumption over time. Key findings indicate 29% of men and 9% of women report drinking in excess of the recommended safe limits, whilst 28% and 8% respectively report binge drinking at least once weekly. Such drinking is not, however, confined to heavy drinkers: 14% of men and 5% of women who drink within the recommended safe limits also report binge drinking at least once weekly. These and other results are discussed in relation to future health promotion initiatives.
Adolescent↗
Reliability of self-reports of alcohol use by community clients.
Eighty-five of 116 randomly selected clients receiving case management services at a comprehensive community mental health center responded anonymously to a survey questionnaire that included two measures of self-reported alcohol use: questions about frequency and quantity and a retrospective diary for reporting the number of drinks consumed daily in the preceding week. Forty-two patients reported using alcohol; consumption was higher among younger patients. A significant correlation was found between responses to the frequency-quantity questions and the information provided in the retrospective diary, indicating that self-reports of alcohol consumption are reasonably reliable for the clients studied. Future research is needed to establish the reliability and validity of self-reported alcohol and drug use in typical treatment settings.
Affective Disorders, Psychotic↗
Sex hormones in postmenopausal women with primary biliary cirrhosis.
To evaluate serum sex hormone profiles in nonalcoholic postmenopausal women with liver disease, 25 women with primary biliary cirrhosis (11 in cirrhotic stage) and 46 healthy controls were studied. The patients had significantly (p less than 0.05) elevated serum concentrations of estrone and androstenedione and significantly (p less than 0.05) lower concentrations of estrone sulfate, dehydroepiandrosterone sulfate and 5 alpha-dihydrotestosterone compared with the 46 controls. Serum concentrations of sex hormone binding globulin, testosterone, non-sex hormone binding globulin-bound testosterone and non-protein-bound testosterone did not differ significantly (p greater than 0.05) between primary biliary cirrhosis patients and controls. Patients in the cirrhotic stage had significantly (p less than 0.05) higher concentrations of sex hormone binding globulin than did controls. Patients in the cirrhotic stage had significantly (p less than 0.05) higher sex hormone binding globulin and estrone sulfate levels compared with noncirrhotic patients with primary biliary cirrhosis. Otherwise, no significant differences were observed between cirrhotic and noncirrhotic patients. The observed changes in steroid concentrations may be a consequence of hepatic dysfunction.
Aged↗
Hyperinsulinaemia is a predictor of non-insulin-dependent diabetes mellitus.
Most incidence studies indicate that baseline plasma glucose, either fasting or post-glucose load, is the best predictor of progression to non-insulin-dependent diabetes mellitus (NIDDM)--the higher the level, the higher the risk. Elevated serum insulin concentrations in the presence of normal fasting plasma glucose levels reflect the presence of insulin resistance and they have also been shown to predict deterioration to NIDDM in a number of populations. Hyperinsulinaemia is a notable characteristic of populations with a high prevalence of NIDDM such as Micronesian Nauruans, American Pima Indians, Mexican-Americans and Asian Indians. In Nauruans and Pima subjects with normal glucose tolerance, those with higher post-load (2-hour) serum insulin at baseline were more likely to progress to either impaired glucose tolerance (IGT) or NIDDM. Conversely, amongst subjects with IGT, progression to NIDDM was predicted by lower (but still high relative to normal) baseline insulin responsiveness. Similar results for subjects with IGT have been described in Japanese. It appears from longitudinal studies that baseline insulin and glucose levels explain much of the association of obesity with risk of NIDDM. It remains to be resolved whether obesity itself may be a manifestation of an underlying defect (such as primary hyperinsulinaemia) which leads to both obesity and NIDDM. The possible sequence of events for the development of NIDDM includes a genetic defect resulting in hyperinsulinaemia and/or insulin resistance and leading ultimately to secondary pancreatic exhaustion with an insulin secretory defect which may also be genetically determined or the result of glucotoxicity.(ABSTRACT TRUNCATED AT 250 WORDS)
Diabetes Mellitus, Type 2↗
Comparison of the effect of cortisol on aromatase activity and androgen metabolism in two human fibroblast cell lines derived from the same individual.
The effect of preincubation with cortisol on estrogen and androgen metabolism was investigated in human fibroblast monolayers grown from biopsies of genital and non-genital skin of the same person. The activity in the cells of aromatase, 5 alpha-reductase, 17 beta-hydroxysteroid oxidoreductase and 3 alpha-hydroxysteroid oxidoreductase was investigated by isolating estrone, estradiol, estriol, dihydrotestosterone, androstanedione, androsterone, 3 alpha-androstanediol, testosterone and androstenedione after incubation of the cells with [14C]testosterone or [14C]androstenedione. For experiments with 14C-labeled substrate the cells were incubated in medium, charcoal stripped of steroids without Phenol Red. Preincubation from 6 to 36 h with cortisol in concentrations of 10(-8) - 10(-6) M showed maximal stimulation of aromatase activity after 12 h preincubation with cortisol in concentrations of 0.5-1.0 x 10(-6) M in both cell lines. When preincubation with cortisol was omitted no estrogen synthesis was detected. The formation of androgen was not altered after preincubation with cortisol. Pronounced differences were found in estrogen and in androgen metabolism in the two cell lines suggesting a local regulation of the hormonal environment. The aromatase activity, which is low in many tissues could be stimulated by cortisol without altering the androgen metabolism was found to be a suitable system for investigations of the cellular interconversion of androgens and estrogens and for investigations of the in vitro regulation of the enzymes involved.
Androgens↗
Fundamental voice frequency in female puberty measured with electroglottography during continuous speech as a secondary sex characteristic. A comparison between voice, pubertal stages, oestrogens and androgens.
The change of fundamental voice frequency in continuous speech in female puberty was analysed in 47 girls by comparison of 2000 consecutive electroglottographic cycles in a reading situation. The results were compared with serum concentrations of androgens (dihydroepiandrosterone, delta-4-androstenedione, testosterone, and sex hormone binding globulin), oestrogens (oestradiol, oestrone, and oestronesulphate), and somatic puberty (weight, height, mamma stages, and pubic hair stages). Fundamental frequency in continuous speech was related only to oestrone r = -0.34, (P less than 0.05). But the tone range in continuous speech and the lowest tone in the phonetogram were found to be significantly correlated with many of the pubertal and hormone parameters. All these correlations could be explained by a common age-dependency. By multiple regression analysis different sets of variables for prediction of speaking fundamental frequency were found before and after menarche.
Adolescent↗
Stress management approaches to the prevention of coronary heart disease.
This paper reviews evidence for the effectiveness of stress management techniques in reducing three risk factors for coronary heart disease: Type A behaviour, raised serum cholesterol, and hypertension. Preliminary evidence suggests that such interventions not only reduce individual risk factors, they can also reduce mortality and morbidity to CHD. Consideration now has to be given to the most effective system of delivery of such interventions.
Coronary Disease↗