Endothelial and smooth muscle properties of coronary and mesenteric resistance arteries in spontaneously hypertensive rats compared to WKY rats

Summary— To investigate if the functional alterations observed in resistance arteries of spontaneously hypertensive rats (SHRs) were also present at the coronary level, in vitro experiments were performed in mesenteric resistance arteries (MRA) and in right (RIC) and left interventricular coronary (LIC) arteries taken from 15–25-week-old SHR and age-matched Wistar Kyoto rats WKYs. Using a passive extension protocol, internal diameters corresponding to 100 mmHg intraluminal pressure (D₁₀₀) were determined and vessels were set up to a normalized internal diameter (0.9 D₁₀₀). SHR mesenteric resistance arteries had a significantly smaller diameter compared to WKY arteries, whereas both types of SHR coronary arteries had a greater diameter compared to those of WKY rats. In arteries in the absence of contracting agonist, nitro-L-arginine (NOLA, 100 μM) induced a progressive rise in basal tone, which could be reversed by subsequent addition of L-arginine (100 μM) but not D-arginine (100 μM). When expressed as percent of maximal contractions induced by agonists (noradrenaline, NA [10 μM] in MRA; serotonin, 5-HT [10 μM], in RIC and LIC), these contractions were significantly stronger in WKY compared to SHR coronary and mesenteric resistance arteries. In NA-precontracted MRA and 5HT-precontracted coronary arteries in the presence of indomethacin (10 μM), the magnitude of acetylcholine-induced maximal relaxations (expressed as percent of maximal contractions induced by agonists) was greater in WKY compared to SHR arteries. After a 30-min incubation period, NOLA (100 μM) completely inhibited relaxations induced by acetylcholine (0.01–10 μM) in all types of precontracted arteries. Subsequent additions of sodium nitroprusside, (SNP, 10 μM) induced complete relaxations in all preparations. These results show that a basal release of NO or NO-like compound by endothelial cells is present in isolated mesenteric resistance and coronary arteries of WKY rats and SHRs. The contribution of endothelium-derived relaxing factor-nitric oxide (EDRF-NO) to arterial tone was lower in MRA compared to coronary arteries in both strains and in SHR compared to WKY arteries. In the SHR preparations, the impaired relaxation induced by acetylcholine appeared to be due to a functional alteration of the endothelium in the presence of normal reactivity of the smooth muscle cells.     

Splicing of the mitochondrial group-II intron rl1: conserved intron-exon interactions diminish splicing efficiency

The mitochondrial intron rI1 is a self-splicing group-II intron of algal mitochondria that can be transferred into chloroplasts from the green alga Chlamydomonas reinhardtii for in vivo investigations (Herdenberger et al. 1994). Thus, rI1 is a suitable system to compare in vitro and in vivo RNA processing. Interestingly, rI1 shows correct RNA splicing, although typical cis-acting exon-sequences (IBS2, δ) of group-II introns are lacking. In order to examine the effect of these exon-intron interactions on splicing, we introduced the endogenous mitochondrial IBS2 sequence in order to produce optimal IBS2-EBS2 base pairing. In addition, the first nucleotide of the 3′exon (δ′) was substituted to create an optimal δ-δ′ interaction. Neither of the two mutations, nor a combination of both, had any effect on the precision of the splice-site selection. Unexpectedly, introduction of IBS2 led to a reduction in the efficiency of the second splicing step in vitro but not in vivo. These findings lead us to conclude that trans-acting factors are present in vivo to optimize splicing efficiency. The possibility is discussed that these factors may, for example, stabilize tertiary intron structures that are a prerequisite for correct RNA processing. Furthermore, our data indicate that similar trans-acting factors promote correct intron splicing in chloroplasts and mitochondria. Received: 18 October / 4 December 1997     

麦冬类中药组织切片计算机三维重建图鉴

利用计算机技术实现麦冬类中药组织连续切片三维重建与动态显示,为计算机辅助生药学鉴定和教学提供了新的三维图像技术和研究资料。     

表小檗碱对α受体的作用

表小檗碱(epiberberine,EB)是从湖北产黄连(Coptis chinensis Franch)中提取的一种生物碱,属苯喹嗪类原小檗碱,对其药理作用的研究资料甚少,未见其对α肾上腺素体作用的报道。资料表明,许多原小檗碱类化合物有α受体阻滞作用,为从该类化合物中选择     

Genetic traits in the area of Bodrogk?z]

In 1984 a late malaria endemic area, called Bodrogk?z was studied. This was a reexamination of the population genetic work performed by Walter, Nemeskéri. In six villages of Bodrogk?z 328 persons were tested for AB0, Rh blood groups, haptoglobins, haemoglobin concentration, haematocrit, erythrocyte amount, the MCV, the MCH and the G-6-PD were analyzed. The quantitative determination of HbF and HbA2, red cell osmotic resistance and thalassemia were measured as well. Thalassemia heterozygote carriers and an increased level of HbF were revealed. The frequency of G-6-PD deficiency was 0.39%. In Bodrogk?z the frequencies of AB0, Rh and haptoglobin types were similar in the present and all previous studies. The background of this similarity might be the genetic similarity between two following generations. On the basis of these facts, the Hb0 Arab and partially DNA work we suggested an alternative hypothesis that these mutant genes got into Bodrogk?z by the rather later migration than with ancient Hungarian people during the period of conquest of Hungary.     

Economics in pediatric type 1 diabetes - results from recently published studies.

OBJECTIVE: Type 1 diabetes in childhood is increasing worldwide. Several therapy components and models of pediatric diabetes care have been introduced. Economic aspects are of increasing interest to decide appropriate strategies in clinical practice. However, knowledge in pediatric diabetes is limited. METHODS: We conducted a literature research to identify and describe systematically recently published analyses on the economics of pediatric diabetes. RESULTS: We substracted ten analyses. Four were cost of illness studies. The main result is that hospitalization, mainly due to metabolic control, education, and acute complications, seems to be a large cost component. Only one study took the perspective of society, including indirect costs. Four of the six studies which evaluated interventions in pediatric diabetes care focussed on ambulatory or home care strategies. Detailed evaluation of new technologies, pharmacotherapy, or screening for late complications is lacking. Except one, all studies performed cost comparison analyses. Evidence is limited, however, diabetes care models may be effective and, possibly, cost saving compared to routine care. CONCLUSIONS: Health economic studies in pediatric diabetes are scarse and limited with respect to topics and quality. Hospitalization has a large impact on health care costs in diabetic children and adolescents. Models in pediatric diabetes care like home intervention may be cost effective compared to more traditional strategies of care. However, further studies are warranted which evaluate clinical and cost effectiveness in pediatric diabetes.