赛庚啶对离体犬心肌肌质网Ca2+,Mg2+—ATP酶活性和45Ca2+摄取功能的影响

当赛庚啶浓度在8×10^-6mol/L～2×10^-4mol/L之间时,该药对正常犬心肌肌质网Ca²⁺,Mg²⁺—ATP酶活性几乎没有影响,仅在10^-3mol/L时对该酶活性才有一定的抑制作用(抑制率为39.85%,P<0.01)。正常犬心肌肌质网的⁴⁵Ca²⁺摄取过程有明显的时间依赖性,至第30 min,其⁴⁵Ca²⁺摄取量可达312.79±22.25 nmol/mg protein.赛庚啶对心肌肌质网的~(45)Ca²⁺摄取有一定的抑制作用,其IC₅₀为1.94×10^-4mol/L。     

Acne vulgaris: endocrine aspects

Androgens play an important part in the development of acne vulgaris. Androgen levels in patients with acne are higher than those in controls and people with the androgen insensitivity syndrome do not develop acne. Local factors other than androgen plasma levels, also play a part in the development of acne. The skin contains enzymes that convert precursor hormones to the more potent androgens such as testosterone and dihydrotestosterone. Androgen synthesis can therefore be regulated locally. The effects of androgens on the skin are the result of circulating androgens and enzyme activity in local tissues and androgen receptors. Acne is a clinical manifestation of some endocrine diseases. The polycystic ovary syndrome has the highest prevalence. In women with acne that persists after puberty, in 10-200% of cases polycystic ovary syndrome is later diagnosed. The mechanism of hormonal anti-acne therapy may work by blocking the androgen-production (oestrogens) or by blocking the androgen receptor (cyproterone, spironolactone).     

Does being bilingual in English and Chinese influence changes in quality of life scale scores? Evidence from a prospective,population based study

Background: Bilinguals differ from monolinguals in language use, but the influence of bilingualism on changes in Health-Related Quality of Life (HRQoL) scores is not known. Objective: To determine the influence of bilingualism on changes in HRQoL scores. Research design: A prospective cohort study of a population-based, disproportionately stratified random sample of monolingual or bilingual ethnic Chinese who completed the Short-Form 36 Health Survey (SF-36) in English or Chinese twice in 2 years. Least squares regression models were used to assess the influence of bilingualism on SF-36 scores, while adjusting for the influence of questionnaire language and determinants of HRQoL. Results: Usable English and Chinese questionnaires were returned by 1013 and 910 subjects respectively (aged 21–65 years, 48.5% female, 52.8% bilingual). Bilinguals differed from monolinguals in known determinants of HRQoL (being younger and better educated), changes in determinants of HRQoL over 2 years (more bilinguals had changes in work or marital status) and had mean SF-36 scores that were up to 10 points higher than monolinguals. After adjusting for these differences, bilingualism did not influence 2 year change scores for any of 8 SF-36 scales. Conclusion: Bilingualism did not influence changes in HRQoL scores over 2 years in this large, population-based study of subjects fluent in English and/or Chinese (representing an alphabet and/or pictogram based language respectively).     

Mutations causing achondroplasia and thanatophoric dysplasia alter bFGF- induced calcium signals in human diploid fibroblasts

Mutations in the fibroblast growth factor receptor (FGFR) gene family recently have been shown to underlie several hereditary disorders of bone development, with specific FGFR3 mutations causing achondroplasia (Ach) and thanatophoric dysplasia (TD). However, for none of these mutations has the defect in receptor function been demonstrated directly and, therefore, for none has the pathophysiological mechanism of the disease been defined. Using our established techniques for single-cell ratiometric real-time calcium image analysis, we defined the nature of the basic fibroblast growth factor (bFGF)-induced calcium signal in human diploid fibroblasts, and, in blinded studies, have analyzed the bFGF-induced signals from 18 independent fibroblast cell lines, including multiple lines from patients with known mutant alleles of FGFR3 and syndromes of Ach or TD. Control cells responded with transient increases in intracellular calcium, with many cells showing oscillatory calcium waves. Homozygous Ach cell lines failed to signal, whereas heterozygous Ach lines responded nearly normally. We observed heterogeneous signals in TD heterozygotes: the unresponsive lines all turned out to carry TD1 alleles, whereas all responsive lines had TD2 alleles. Since FGFR1, 2 and 3 receptors are known to be expressed in fibroblasts, our results suggest that specific mutant FGFR3 alleles can function in a dosage-dependent dominant-negative fashion to inactivate FGFR signaling.      

Nicotinic acetylcholine currents in cultured postnatal rat hippocampal neurons.

Nicotinic acetylcholine (ACh) currents were studied in cultured postnatal rat hippocampal neurons, using whole-cell voltage-clamp techniques. In most cells, ACh produces one of two types of response. One class of ACh currents exhibits rapid and profound desensitization and is sensitive to inhibition by alpha-bungarotoxin (alpha BTXN). The second class activates slowly and exhibits no desensitization during prolonged agonist applications. This slow current is insensitive to alpha BTXN. Both the fast and slow responses exhibit inwardly rectifying current-voltage relationships and pass little current at positive membrane potentials. Both currents can be recorded in the presence of 1 microM atropine but are blocked by 0.1-1.0 mM d-tubocurarine and 0.1-1.0 mM mecamylamine. These observations suggest heterogeneity of nicotinic ACh receptors in rat hippocampal neurons and provide support for functional alpha BTXN-sensitive nicotinic receptors in this region.