Tobacco: a major challenge for the developing world.
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Developing Countries↗
Biomedical subjects
K Ball
Publications and source records attributed to K Ball.
Concentrations of immunoreactive inhibin in ovarian and peripheral venous plasma and follicular fluid of Booroola ewes that are homozygous carriers or non-carriers of the FecB gene.
No gene-specific differences were found during either the luteal or follicular phases of the oestrous cycle in the venous secretion rates of ovaries or in concentrations of immunoreactive inhibin in peripheral plasma between Booroola ewes that were homozygous carriers (BB) or non-carriers (++) of the FecB gene. In three experiments in which concentrations of plasma inhibin and follicle-stimulating hormone (FSH) were compared, gene-specific differences were noted for FSH (P less than 0.05), but no significant correlations were noted between FSH and inhibin for either genotype. Granulosa cells and follicular fluid, but not theca interna, stroma or corpora lutea, were the major intra-ovarian sites of inhibin; no gene-specific differences were noted for inhibin concentrations in follicular fluid or in any of the intra-ovarian tissues. The mean concentrations of inhibin in follicular fluid remained constant irrespective of follicular diameter whereas the mean total contents of inhibin increased significantly with increasing diameter (P less than 0.05). Inhibin secretion rates were four times higher in ovaries with oestrogen-enriched follicles (i.e. greater than or equal to 50 ng oestradiol ml-1) than in ovaries with no such follicles (P less than 0.01). Moreover, inhibin concentrations were higher in follicular fluid of oestrogen-enriched follicles than in those with low oestrogen (i.e. less than 50 ng ml-1; P less than 0.05). Ovariectomy resulted in a significant reduction in concentrations of immunoreactive inhibin from plasma (P less than 0.01). The residual plasma inhibin in some Booroola ewes was not associated with genotype. It is concluded that, although antral follicles are a major source of inhibin in Booroola ewes, immunoreactive inhibin is not associated with the FecB gene and is not responsible for the gene-specific differences in concentrations of FSH in plasma.
Analysis of Variance↗
Conducting laser research.
Nurses today are sometimes reluctant to get involved with research due to their lack of involvement or experience. This article simplifies the research process by comparing its steps with the familiar steps of the nursing process. Laser technology offers nurses the challenge of an ever-changing arena in which research projects can be easily identified and conducted.
Humans↗
Visual/cognitive correlates of vehicle accidents in older drivers.
Older drivers have more accidents per miles driven than any other age group and tend to have significant impairments in their visual function, which could interfere with driving. Previous research has largely failed to document a link between vision and driving in the elderly. We have taken a comprehensive approach by examining how accident frequency in older drivers relates to the visual/cognitive system at a number of levels: ophthalmological disease, visual function, visual attention, and cognitive function. The best predictor of accident frequency as recorded by the state was a model incorporating measures of early visual attention and mental status, which together accounted for 20% of the variance, a much stronger model than in earlier studies. Those older drivers with a visual attentional disorder or with poor scores on a mental status test had 3-4 times more accidents (of any type) and 15 times more intersection accidents than those without these problems.
Accidents, Traffic↗
Starch biosynthesis and its regulation.
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Amino Acid Sequence↗
Identification and functional significance of troponin I isoforms in neonatal rat heart myofibrils.
We investigated the mechanism(s) responsible for differences in the effects of acidic pH on Ca2+ activation of the activity of adult and neonatal rat heart myofilaments. Studies on preparations of myofilaments reconstituted with adult troponin-tropomyosin (Tn-Tm) and either adult or neonatal thick filaments indicated that the difference in effect of acidic pH is related to differences in Tn-Tm and not other myofilament proteins. Immunoblotting analysis showed that development of the rat heart myofibrils is associated with isoform switching from slow skeletal TnI to cardiac TnI and from a slow mobility isoform of TnT (TnT1) to a faster Mr isoform (TnT2. Expression of slow skeletal TnI was associated with a relative insensitivity of myofilament Ca2+ activation to deactivation by acidic pH. Moreover, the effect of acidic pH on Ca2+ activation of ATPase activity of soleus myofibrils, which contain cardiac TnC and slow skeletal TnI, was essentially the same as the effect of acidic pH on rat cardiac myofibrils in the early neonatal period. Neonatal myofilaments also contained a relative abundance of a set of polypeptides copurifying with the thin filaments. We have identified these proteins as histones. The relative amount of histones among a variety of preparations from different species was not correlated with the pH sensitivity of myofibrillar Ca2+ activation. Shifts in TnT isoforms among these species were also not correlated with an altered response to acidic pH. Our data provide evidence in support of the hypothesis that the relative insensitivity of neonatal myofilament activity to acidic pH is due to the presence of slow skeletal TnI in the thin-filament regulatory complex.
Acids↗
The effects of infusion of insulinlike growth factor (IGF) I, IGF-II, and insulin on glucose and protein metabolism in fasted lambs.
In vivo effects of 300-min infusions of recombinant insulinlike growth factor I (IGF-I) and IGF-II on glucose and protein metabolism have been investigated in awake, fasted lambs. Two doses of recombinant human (rh) IGF-I were infused: 6.7 nmol/kg.h, which induced hypoglycemia, and 2.0 nmol/kg.h, which did not. The effects were compared with an insulin infusion (0.17 nmol/kg.h) that had the same hypoglycemic potential as the high dose rhIGF-I infusion. rhIGF-II was infused at a rate of 6.7 nmol/kg.h. Primed constant infusions of isotopically labeled glucose, urea and leucine tracers were used to determine glucose and protein kinetics. rhIGF-I lowered blood glucose by increasing the rate of glucose clearance (P less than 0.01), in contrast to insulin, which both increased clearance and reduced glucose production. Net protein loss was reduced after infusion of low and high dose rhIGF-I and insulin by 11% (P less than 0.05), 15% (P less than 0.01), and 12% (P less than 0.05), respectively. rhIGF-II infusion did not alter the rate of net protein loss. In contrast to insulin, high dose rhIGF-I infusion increased the rate of protein synthesis in skeletal (P less than 0.05) and cardiac muscle (P less than 0.01) and in hepatic tissue (P less than 0.05). We conclude that (a) protein metabolism is more sensitive than glucose metabolism to rhIGF-I infusion, as protein loss was reduced by an rhIGF-I infusion that did not alter glucose kinetics; (b) protein synthesis is increased by rhIGF-I infusion but not by insulin infusion; and (c) rhIGF-II is a less effective anabolic agent than rhIGF-I. We speculate that the effects of rhIGF-I on protein metabolism are not mediated by insulin receptors.
Animals↗
Identifying correlates of accident involvement for the older driver.
Most older adults rely on the automobile to maintain their mobility and independence, in spite of the fact that age-related behavioral and biomedical changes may make driving more difficult. Indeed, accident and fatality rates begin to rise after age 55. One research goal, therefore, is to identify functional measures that differentiate older adults who drive safely from those who do not. This paper discusses conceptual and methodological issues involved in addressing this question, considers why earlier research has been largely unsuccessful, presents a working model for approaching the problem, and argues the need for large-sample, prospective research in this area.
Accidents, Traffic↗
GnRH-induced gonadotrophin secretion in ovariectomized Booroola ewes with hypothalamic-pituitary disconnection.
To test whether the F gene-specific differences in the plasma concentrations of FSH and LH are due to differences in the pituitary responsiveness to exogenous GnRH, ovariectomized Booroola ewes with hypothalamic-pituitary disconnection (HPD-ovx) were treated with GnRH (250 ng i.v.) once every 2 h for up to 5 weeks. In Exp. 1, jugular venous blood was collected once weekly from 13 FF and 14 ++ HPD-ovx ewes for 6 weeks before GnRH treatment and every 2nd, 3rd or 6th day for 5 weeks during treatment. In Exp. 2, jugular venous blood was collected from another 8 FF and 7 ++ HPD-ovx ewes at 5- or 10-min intervals over 4 GnRH pulses (250 ng i.v. once every 2 h) on 3 separate occasions after the animals had been subjected to the GnRH pulse regimen for approximately 7 days beforehand. Also in Exp. 2, the animals were extensively sampled around a larger (10 micrograms) i.v. injection of GnRH and the pituitary FSH and LH contents assessed after the animals had been re-exposed to the once every 2 h GnRH (250 ng i.v.) pulse regimen for several days following the larger GnRH bolus. In Exp. 3 the distributions of mean plasma concentrations of FSH and LH in individual GnRH-treated HPD-ovx ewes were compared with those in ovariectomized and ovary-intact FF and ++ ewes. During the 6 weeks before GnRH treatment (Exp. 1), the plasma concentrations of FSH (approximately 1 ng/ml) and LH (less than or equal to 0.8 ng/ml) were not different between the genotypes. After GnRH treatment both the mean FSH and LH concentrations increased significantly (P less than 0.01) above basal values after 2 days with F gene-specific differences being noted for FSH but not LH (FSH; FF greater than ++; P less than 0.05). Thereafter, the mean FSH but not LH concentrations increased at a faster rate in FF than in ++ ewes with the overall mean FSH concentrations between the genotypes being significantly different (P less than 0.05). In Exp. 2 considerable between-animal variation in the pulsatile pattern of FSH but not LH concentrations was seen in ewes of both genotypes during GnRH treatment. The overall mean FSH concentrations were higher in FF than in ++ ewes (P less than 0.05) and the mean FSH response to each GnRH pulse was significantly higher in FF than in ++ ewes (P less than 0.05).(ABSTRACT TRUNCATED AT 400 WORDS)
Animals↗
Visual and cognitive predictors of driving problems in older adults.
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Accidents, Traffic↗
The ontogeny of [3H]5-hydroxytryptamine binding in the lamb: effects of in vivo thyroidectomy.
The effects of congenital hypothyroidism in the late gestation ovine fetus include changes in serotonin concentrations in specific brain areas. To investigate possible ontogenic patterns of changes in 5-HT receptor function, we studied the binding characteristics of [3H]5-HT in the midbrain, hypothalamus and cerebral cortex in the late gestation ovine fetus and young lamb. We compared the binding characteristics of control fetuses to those of thyroidectomized fetuses, with or without thyroxine replacement therapy. In each of the areas examined, age-dependent changes in the receptor density (Bmax) for [3H]5-HT was observed. In cerebral cortex, Bmax was constant from 120 days gestation through the early neonatal period and increased significantly only at 25-30 days after birth. In hypothalamus, [3H]5-HT binding density decreased late in gestation (140-145 days) with a return after birth to values comparable to those at 120-125 and 130-135 days gestation. The midbrain also exhibited a significant age-dependent pattern of altered receptor density with a decrease in the 130-135 and 140-145 day gestational age groups compared to both younger and older lambs. In contrast, the affinity constant (Kd) for [3H]5-HT did not change over the ages evaluated in cerebral cortex or hypothalamus. In the midbrain, however, there was a significant increase in Kd at 1-5 days after birth compared to all other age groups. The ability of fetal thyroidectomy, with or without thyroxine replacement therapy, to alter patterns of [3H]5-HT binding was also tested.(ABSTRACT TRUNCATED AT 250 WORDS)
Aging↗
Oocyte production and ovarian steroid concentrations of immature rats in response to some commercial gonadotrophin preparations.
Four commercial gonadotrophin preparations, namely Folligon, F.S.H.-P., Folltropin and Ovagen, were examined for their effects on oocyte production and ovarian steroid concentrations in immature rats. The ratios of the FSH to LH concentrations of the preparations, determined by radioreceptor assays, were Folligon 5, F.S.H.-P. 18, Folltropin 49 and Ovagen 1090. Forty-eight hours after administering each gonadotrophin preparation to immature rats, ovulation was induced by injection of chorionic gonadotrophin. Twenty-four hours later, oocytes were recovered from the oviducts and counted. Oocytes were produced after injection of chorionic gonadotrophin following a single injection of Folligon (10-50 i.u.). However, no oocytes were produced in response to the other gonadotrophin preparations unless they were administered by continuous infusion (30-1000 micrograms day-1). When given by injection (Folligon) or infusion (others), the gonadotrophin preparations all promoted a dose-dependent increase in mean oocyte production, except at the highest doses when mean oocyte numbers either remained unchanged or declined significantly in the cases of Folligon and F.S.H.-P. The highest mean numbers of oocytes produced in response to Folltropin (48 +/- 9 oocytes, mean +/- s.e.m.) and Ovagen (47 +/- 7) were greater than those attained with Folligon (21 +/- 6) or F.S.H.-P. (31 +/- 5). Mean ovarian weights also increased in a dose-dependent fashion in response to each of the gonadotrophin preparations. Measurements of ovarian steroid concentrations 48 h after the onset of gonadotrophin treatment (i.e. immediately prior to ovulation induction with chorionic gonadotrophin) showed that the gonadotrophin preparations markedly influenced the ratios of ovarian oestradiol-17 beta and androgen (androstenedione plus testosterone) concentrations. At low doses the gonadotrophin preparations increased the ratio of oestradiol-17 beta to androgens, but at the highest doses, with the exception of Ovagen, the ratio was reduced relative to peak values. Co-infusion of ovine LH (NIADDK-oLH-25; 10-20 micrograms day-1) with Ovagen (250 micrograms day-1) or ovine FSH (10 micrograms day-1, NIADDK-oFSH-17), both low in LH content, increased the mean number of oocytes produced and also the ovarian oestradiol-17 beta:androgen concentration ratio. However, with 40 micrograms LH day-1, the oestradiol-17 beta:androgen ratio fell due to a continued increase in mean ovarian androgen concentrations and a decrease in mean ovarian oestradiol-17 beta concentration. The mean number of oocytes produced also fell significantly.(ABSTRACT TRUNCATED AT 400 WORDS)
Androstenedione↗
Exporting death. Britain's malignant epidemic spreads to the developing world.
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Developing Countries↗
Seasonal koilonychia in Ladakh.
During a health survey for chest disease in Ladakh, it was noted that women and a few men had marked koilonychia. It caused disfigurement, discomfort and sometimes disturbance of function. It occurred mainly in spring and summer and usually disappeared in winter. It is thought to be due to exposure to cold wet mud while repairing walls and irrigation canals. There was no evidence of iron deficiency.
Adult↗
Changes in selected brain neurotransmitters and their metabolites in the lamb after thyroidectomy during the last two trimesters of gestation or the early neonatal period.
To evaluate in a development context the effect of congenital hypothyroidism on concentrations of the neurotransmitters norepinephrine, dopamine, and serotonin (5HT) in selected brain areas of the ovine fetus, we studied the effect of thyroidectomy at three ages on the concentrations of these neurotransmitters and their major metabolites, homovanillic acid and 5-hydroxyindoleacetic acid. Fetuses underwent thyroidectomy at 90-95 or 105-115 d gestation (term = 147-150 d) or 1-5 d after birth. Approximately 25 d after thyroidectomy, at d 120-125 or 130-135 of gestation or 25-30 d after birth, respectively, the ewes were killed and fetal brains removed. Neurotransmitters and their metabolites were measured by HPLC with electrochemical detection. Thyroidectomy in the 2nd trimester increased 5HT in five brain areas: anterior hypothalamus, dorsal medial hypothalamus, pons, medulla, and cerebellum. Thyroidectomy in the 3rd trimester increased 5HT in the pons and medulla, increased norepinephrine in the dorsal medial hypothalamus and pons, and increased homovanillic acid in the posterior hypothalamus. Thyroidectomy in the newborn period decreased NE in the anterior hypothalamus, ventral medial hypothalamus, and midbrain, decreased 5-hydroxyindoleactic acid in the posterior hypothalamus, lateral hypothalamus, dorsal medial hypothalamus, and ventral medial hypothalamus, and decreased homovanillic acid in the dorsal medial hypothalamus and ventral medial hypothalamus. From these data we conclude the following: 1) Hypothyroidism causes changes in neurotransmitter concentrations only in selected brain areas of the ovine fetus, rather than causing generalized and similar changes in all brain areas; and 2) 5HT 5-hydroxyindoleacetic acid concentrations are affected more often than the other neurotransmitters evaluated, perhaps because the 5HT neurotransmitter system is developing at these times.
Animals↗
Expanded ontogeny of neurotransmitters and their metabolites in the brains of fetal and newborn lambs.
To evaluate the ontogeny of the brain neurotransmitters norepinephrine, dopamine, serotonin and the metabolites hydroxyindoleacetic acid and homovanillic acid, we measured these neurotransmitters in 10 brain areas at three ages in fetal sheep and two ages in newborn lambs. Norepinephrine exhibited an increase only at 25-30 days after birth in the midbrain, lateral hypothalamus, dorsal medial hypothalamus and ventral medial hypothalamus. Dopamine concentration was very low and did not change over the ages examined. Homovanillic acid decreased after 125 days in the cerebellum, but this change is probably not biologically meaningful, since there were no statistically significant changes in homovanillic acid in other brain areas. Serotonin increased at 25-30 days after birth in the ventral medial hypothalamus, but changes in other brain areas were not significant. Hydroxyindoleacetic acid reached its greatest concentration at 1-5 days after birth in nine of the ten brain areas examined. Thus we conclude that the serotonin system is undergoing more change in the last third of gestation and first month of extrauterine life than the norepinephrine or dopamine systems.
Animals↗
Special messages. Bob's story--Janet's story.
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Adult↗
Differences in the plasma concentrations of FSH and LH in ovariectomized Booroola FF and ++ ewes.
During 12 sampling days before ovariectomy the mean plasma FSH but not LH concentrations in FF ewes were higher (P less than 0.01) than those in ++ ewes (16 ewes/genotype). After ovariectomy increases in the concentrations of FSH and LH were noted for ewes of both genotypes within 3-4 h and the rates of increase of FSH and LH were 0.18 ng ml-1 h-1 and 0.09 ng ml-1 h-1 respectively for the first 15 h. From Days 1 to 12 after ovariectomy, the overall mean +/- s.e.m. concentrations for FSH in the FF and ++ ewes were 8.1 +/- 0.6 and 7.1 +/- 0.4 ng/ml respectively and for LH they were 2.7 +/- 0.3 and 2.1 +/- 0.2 ng/ml: these differences were not statistically significant (P = 0.09 for both FSH and LH; Student's t test). However, when the frequencies of high FSH or LH values after ovariectomy were compared with respect to genotype over time, significant F gene-specific differences were noted (P less than 0.01 for both FSH and LH; median test). In Exp. 2 another 21 ewes/genotype were blood sampled every 2nd day from Days 2 to 60 after ovariectomy and the plasma concentrations of FSH and LH were more frequently higher in FF than in ++ ewes (P less than 0.01 for FSH and LH). The F gene-specific differences in LH concentration, observed at 21-36 days after ovariectomy were due to higher mean LH amplitudes (P less than 0.025) but not LH peak frequency in FF than in ++ ewes.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗