Serum concentration of prolactin, gastrin and glycocholic acid in patient with peptic ulcer treated with ranitidine

In 66 patients with peptic ulcer (11 with gastric ulcer, 55 with duodenal ulcer, 19 women, 47 men) the serum concentrations of prolactin, dehydrocholic acid and gastrin were determined. The studies were repeated after treatment with ranitidine: in 50 patients after three weeks and in 40 patients after another 30 days. During the first period ranitidine 2 x 150 mg was administered, while during the second period the dose was 1 x 150 mg. The results were compared with those obtained from 120 healthy subjects. Before starting the treatment prolactin levels were significantly higher than those in the control group. During the treatment a significant decrease of the levels was observed. Similar changes of prolactin concentrations were found in the group of 39 men with duodenal ulcer isolated from the studied patients, who were compared with a group of 50 healthy men. It was not found that the development of peptic ulcer and the treatment with ranitidine exerted and effect on the changes of gastrin and dehydrocholic acid concentrations.     

Sugar-Induced Increase of Calcium-Dependent Protein Kinases Associated with the Plasma Membrane in Leaf Tissues of Tobacco

The sugar-inducible expression of genes for sporamin and [beta]-amylase in leaf explants of sweet potato (Ipomoea batatas) and that of a [beta]-glucuronidase-fusion gene, with the promoter of the gene for [beta]-amylase in leaves of tobacco (Nicotiana tabacum), requires Ca2+ signaling (M. Ohto, K. Hayashi, M. Isobe, K. Nakamura [1995] Plant J 7: 297-307), and it was inhibited by staurosporin and K252a, inhibitors of protein kinases. Autophosphorylation activities of several potential protein kinases in leaves of tobacco were significantly higher in younger leaves than in mature leaves. However, the autophosphorylation activities of these proteins in mature leaves, especially those of the major autophosphorylatable proteins with apparent molecular masses of 56 and 54 kD, increased upon treatment of leaf discs with a 0.3 M solution of sucrose, glucose, or fructose, did not increase with sorbitol or mannitol treatments, and the increase by sucrose was inhibited by cycloheximide. Autophosphorylation of the 56- and 54-kD protein in vitro was dependent on Ca2+ and inhibited by staurosporine, K-252a, and by W-7. These results suggest that they belong to the family of calcium-dependent protein kinases. They were concentrated in the plasma membrane fraction and were released from membrane vesicles by high salt or with sodium carbonate. The possible functions of these sugar-inducible calcium-dependent protein kinases associated with the plasma membrane are discussed.     

Desensitization of the skeletal muscle ryanodine receptor: evidence for heterogeneity of calcium release channels.

Ca release channels from the junctional sarcoplasmic reticulum (SR) membranes of rabbit skeletal muscle were incorporated into the lipid bilayer membrane, and the inactivation kinetics of the channel were studied at large membrane potentials. The channels conducting Cs currents exhibited a characteristic desensitization that is both ligand and voltage dependent: 1) with a test pulse to -100 mV (myoplasmic minus luminal SR), the channel inactivated with a time constant of 3.9 s; 2) the inactivation had an asymmetric voltage dependence; it was only observed at voltages more negative than -80 mV; and 3) repetitive tests to -100 mV usually led to immobilization of the channel, which could be recovered by a conditioning pulse to positive voltages. The apparent desensitization was seen in approximately 50% of the experiments, with both the native Ca release channel (in the absence of ryanodine) and the ryanodine-activated channel (1 microM ryanodine). The native Ca release channels revealed heterogeneous gating with regard to activation by ATP and binding to ryanodine. Most channels had high affinity to ATP activation (average open probability (po) = 0.55, 2 mM ATP, 100 microM Ca), whereas a small portion of channels had low affinity to ATP activation (po = 0.11, 2 mM ATP, 100 microM Ca), and some channels bound ryanodine faster (< 2 min), whereas others bound much slower (> 20 min). The faster ryanodine-binding channels always desensitized at large negative voltages, whereas those that bound slowly did not show apparent desensitization. The heterogeneity of the reconstituted Ca release channels is likely due to the regulatory roles of other junctional SR membrane proteins on the Ca release channel.     

东亚大都市学生头型的比较研究

为了研讨居住区域的气候条件和社会经济环境对头型的影响,采用国际通用的人体测量法,调查测量了东亚三个国家四个集团３４７２名６－１７岁学生的头长和头宽,经统计学处理求得其平均值、头指数,回归方程,并作性差和地区差检验,其结果表明：中国大连学生为特圆头型,菲律宾马尼拉学生为圆头型,地理位置在大连和马尼拉之间的日本东京的学生的头型也位于二者之间,生活富裕集团的头长和头宽明显大于生活贫穷集团的学生,但头型二     

Preliminary investigation of feeding performance of larvae of early red-spotted grouper, Epinephelus coioides, reared with mixed zooplankton

Larvae of red-spotted grouper, Epinephelus coioides, were reared inoutdoor tanks with nauplii of copepods (mainly Pseudodiaptomus annandaleiand Acartia tsuensis) and/or rotifers, Brachionus rotundiformis. Grouperlarvae successfully started feeding on early stage nauplii even though theirabundance was as low as approximately 100 individuals l^–1 andshowed better survival and growth thereafter compared to those fed withrotifers only. Incidence of feeding reached 100% on day 4 whennauplii were available and only on day 9 when rotifers were given alone.Larvae seemed to be poor feeders at the onset of feeding, attempting tocapture any food organisms in the tank water. Selective feeding ability oflarvae started from day 4 and the larvae then preferred to feed on medium-and large-size nauplii rather than on rotifers as they grew. Larvae appearedto have a better chance at surviving in the presence of early stage nauplii,which were probably caught more easily than rotifers.     

Targeting Determinants and Proposed Evolutionary Basis for the Sec and the Delta pH Protein Transport Systems in Chloroplast Thylakoid Membranes

Transport of proteins to the thylakoid lumen is accomplished by two precursor-specific pathways, the Sec and the unique Delta pH transport systems. Pathway selection is specified by transient lumen-targeting domains (LTDs) on precursor proteins. Here, chimeric and mutant LTDs were used to identify elements responsible for targeting specificity. The results showed that: (a) minimal signal peptide motifs consisting of charged N, hydrophobic H, and cleavage C domains were both necessary and sufficient for pathway-specific targeting; (b) exclusive targeting to the Delta pH pathway requires a twin arginine in the N domain and an H domain that is incompatible with the Sec pathway; (c) exclusive targeting to the Sec pathway is achieved by an N domain that lacks the twin arginine, although the twin arginine was completely compatible with the Sec system. A dual-targeting signal peptide, constructed by combining Delta pH and Sec domains, was used to simultaneously compare the transport capability of both pathways when confronted with different passenger proteins. Whereas Sec passengers were efficiently transported by both pathways, Delta pH passengers were arrested in translocation on the Sec pathway. This finding suggests that the Delta pH mechanism evolved to accommodate transport of proteins incompatible with the thylakoid Sec machinery.     

Anthropometrics Do Not Influence Dual X-ray Absorptiometry (DXA) Measurement of Fat in Normal to Obese Adults: A Comparison with In Vivo Neutron Activation Analysis (IVNA)

Dual-energy X-ray absorptiometry (DXA) is now a commonly used method for the determination of bone mineral status and body composition in humans. The purposes of this study were to compare fat mass by in vivo neutron activation analysis (FM_IVNA) with that by DXA (FM_DXA) in an anthropometrically heterogeneous sample of healthy adult men (n=33) and women (n=36) (19=≤BMI≤39), and to determine whether differences in fat mass estimates between the two methods (ΔFM) were attributable to subject anthropometry as defined by several circumference (waist, iliac crest, thigh) and skinfold thickness (umbilical, suprailiac, abdominal) measurements. No significant differences between FM_DXA and FM_IVNA were observed in men (p=0.46) or women (p=0.09). The two methods were very highly correlated in both sexes (women r²=0.97, p<0.001, men r²=0.91, p<0.001), although the regression line for men was significantly different from the line of identity (p=0.043). These results suggest modest trends toward underestimation of FM_DXA in men when FM_IVNA<18 kg, and overestimation in men when FM_IVNA>18 kg. ΔFM (IVNA-DXA) was not significantly related to any combination of skinfold thicknesses and circumferences in either gender. Age explained 27% of the variance in ΔFM for the men (p=0.008). Furthermore, ΔFM was not significantly related to inter-method disparity in total-body bone mineral measurements in men or women (p<0.05). The present study demonstrates strong correlation in fat measurements between IVNA and DXA in men and women ranging from normal to markedly obese. Correction for subject anthropometry does not significantly improve this relationship.     

蚤数量与宿主数量和气象因子的关系

根据内蒙古自治区鄂托克旗和鄂托克前旗1975一1989年长爪沙鼠密度、蚤指数监测数据和本地区气象站的,项气象因子资料,分别求出了蚤指数与鼠密度的直线和曲线的回归模型,与气象因子的最优回因子集模型和标准回归模型,给出了鼠蚤因子和气象因子间的典型棺关分析。结论：宿主数量变化导致蚤指数变化;气象因子综合影响蚤指数;相对湿度和地表温度是影响蚤数量变动的重要因子;气象因于对蚤指数的影响大于对鼠密度的影响。     

帕里红景天的化学成分研究

从帕里红景天根茎的石油醚和乙醇提取部分共分得１４种结晶性化合物,经光谱分析和化学反应,分别鉴定为二十二醇、二十六酸、十九醇、β－谷甾醇、二十九醇、红景天甙、麦芽糖、棉皮素－８－葡萄糖甙、胡萝卜甙、酪醇、咖啡酸、没食子酸、形花内酯和新化合物帕里甙。     

Escherichia coli alkaline phosphatase: X-ray structural studies of a mutant enzyme (His-412-->Asn) at one of the catalytically important zinc binding sites.

The X-ray structure of a mutant version of Escherichia coli alkaline phosphatase (H412N) in which His-412 was replaced by Asn has been determined at both low (-Zn) and high (+Zn) concentrations of zinc. In the wild-type structure, His-412 is a direct ligand to one of the two catalytically critical zinc atoms (Zn1) in the active site. Characterization of the H412N enzyme in solution revealed that the mutant enzyme required high concentrations of zinc for maximal activity and for high substrate and phosphate affinity (Ma L, Kantrowitz ER, 1994, J Biol Chem 269:31614-31619). The H412N enzyme was also inhibited by Tris, in contrast to the wild-type enzyme, which is activated more than twofold by 1 M Tris. To understand these kinetic properties at the molecular level, the structure of the H412N (+Zn) enzyme was refined to an R-factor of 0.174 at 2.2 A resolution, and the structure of the H412N(-Zn) enzyme was refined to an R-factor of 0.166 at a resolution of 2.6 A. Both indicated that the Asn residue substituted for His-412 did not coordinate well to Zn1. In the H412N(-Zn) structure, the Zn1 site had very low occupancy and the phosphate was shifted by 1.8 A from its position in the wild-type structure. The Mg binding site was also affected by the substitution of Asn for His-412. Both structures of the H412N enzyme also revealed a surface-accessible cavity near the Zn1 site that may serve as a binding site for Tris.(ABSTRACT TRUNCATED AT 250 WORDS)