Studies of the Sal I strain of Plasmodium vivax in the squirrel monkey (Saimiri sciureus)

The Sal I strain of Plasmodium vivax was successfully adapted to three phenotypes of the squirrel monkey, Saimiri sciureus. Through five linear blood passages, parasitemias in excess of 200,000/mm3 blood were attained; Bolivian phenotype Saimiri appear to develop higher peak parasitemias. Sporozoites of the Sal I strain inoculated intravenously produced patent parasitemias in all five squirrel monkeys challenged, with prepatent periods ranging from 21 to 38 days. Anopheles freeborni and An. gambiae were the most susceptible of eight anopheline species fed on infected squirrel monkeys. As a model for in vivo studies of P. vivax the Sal I strain in Saimiri has great potential.     

The proteolytic digestion of ox neurofilaments with trypsin and alpha-chymotrypsin.

Brief digestion of ox neurofilaments with trypsin liberates fragments that are soluble and have molecular weights ranging from 164 000 to 97 000. Peptide fingerprinting indicates that these regions, termed the tryptic head-regions, arise from the 205 000- and 158 000-mol.wt. components of the triplet. The remains of the parent polypeptides sediment with normal filaments and have been termed tail-regions. Digestion of neurofilaments with chymotrypsin also liberates soluble fragments (chymotryptic head-regions) but these have mol.wts. 171 000 and 119 000, though they too originate from the higher-molecular-weight triplet polypeptides. Tryptic and chymotryptic head-regions have extensive homology, and a low (less than or equal to 20%) helix content. Electron microscopy shows that chymotryptic digestion rapidly reduces the length of filaments, probably because this enzyme preferentially attacks the 72 000-mol.wt. polypeptide. In contrast, brief digestion with trypsin does not reduce filament length even though more than 90% of the two higher-molecular-weight components have been cleaved. These results indicate that the backbone of native filaments is formed from the 72 000-mol.wt. polypeptide together with the tail-regions from the 205 000- and 158 000-mol.wt. polypeptides. The corresponding head-regions of these components, which can represent nearly 75% of each molecule, are not necessary for preserving the backbone of native neurofilaments and are therefore good candidates for being the side arms that connect these filaments in nerve cells.     

The efficacy of biobehavioral and compliance interventions in the adjunctive treatment of mild pregnancy-induced hypertension

This investigation assessed the efficacy of a biobehavioral intervention in the adjunctive treatment of mild pregnancy-induced hypertension (PIH), a potentially serious complication of pregnancy in which normotensive women develop hypertension, proteinuria, and edema of unknown etiology late in gestation. Forty-five women with symptoms of PIH were randomly assigned to one of three treatment conditions: bed rest alone (the most common obstetrical treatment), bed rest with individualized compliance enhancement training, or a four-session biobehavioral treatment consisting of bed rest, compliance enhancement training, and individualized thermal biofeedback-assisted relaxation training. Results indicated that while blood pressure for the bed rest and compliance enhancement groups continued to rise and pose an increasing health risk to maternal and fetal well-being, subjects in the biobehavioral group maintained their blood pressure at a significantly lower, and presumably safer, level. The biobehavioral treatment is hypothesized to affect blood pressure levels in subjects with mild PIH through the mediation of the sympathetic nervous system, decreasing peripheral vascular resistance and cardiac output. The results of this investigation suggest that the biobehavioral intervention may be an effective adjunct to bed rest in the treatment of mild PIH remote from term.     

Breathing during sleep with mild hypoxia

To investigate ventilatory response to mild hypoxia during non-rapid-eye-movement sleep, we administered approximately 16% O2 (which corresponds to concentrations found in commercial high altitude air craft) to 12 normal subjects by using a Venturi mask, which did not alter the breathing pattern during this study. Under mild hypoxia, inspiratory minute ventilation during sleep showed an initial rapid increase (P less than 0.001) but then declined significantly (P less than 0.001) and stabilized. Stable levels differed among individuals and, compared with those measured before hypoxia, were significantly lower in some subjects, higher in one, and essentially unchanged in the others. The initial rapid increase in minute ventilation after mild hypoxia during sleep correlated with the respective values of hypoxic ventilatory response during the awake state (P less than 0.01), but the final lowered levels did not. We conclude that the ventilatory response after mild hypoxia during sleep is biphasic and hypoxic depression exerts considerable influence on ventilation under mild hypoxia during sleep. So we should take hypoxic depression into consideration to evaluate the response to hypoxia during sleep.     

应用酶联免疫吸附试验检测不同类型乙型肝炎中激活补体类HBsAg循环免疫复合物

本文以抗人C_(?)的羊IgG为包被抗体,以HRP-HBs抗体为指示抗体,建立了可检测激活补体类HBsAg循环免疫复合物(HBsAg/C3-CIC)的C_3捕捉法酶联免疫吸附试验。检测了236例六种类型临床诊断为乙型肝炎的病人血清标本,其阳性率分别为:无症状携带者(ASC)12.9％(4/31),急性肝炎(AH)36.7％(22/60),慢性迁延性肝炎(CPH)33.3％(7/21),慢性活动性肝炎(CAH)59.6％(34/57),重型肝炎(SH)77.8％(14/18),肝炎后肝硬化(PLC)67.3％(33/49),阳性率与肝损严重程度明显相关(P<0.01)。认为HBs-Ag/C3-CIC可能在乙型肝炎病毒引起的慢性活动性肝炎、重型肝炎和肝炎后肝硬化的发病过程中起重要作用,并可作为乙型肝炎的诊断、临床分型和预后判断的指标之一。     

大麦条纹花叶病毒新疆株(BSMV-XJ)RNA_2的cDNA克隆及5′端序列分析

分离了大麦条纹花叶病毒(BSMV)新疆株基因组的3个RNA组份。以RNA2为模板,3′端互补寡核苷酸为引物,合成了第一条cDNA链和第二条cDNA链,将ds-cDNA重组在pUC9质粒中,转化大肠杆菌细胞,获得含RNA3′端的克隆,并证明所选克隆的cDNA含有新疆株几近全长的RNA2组份。对于插入片段为3.3kbp的112号克隆进行了酶谱分析,得到了与国外典型株类似的结果;用双脱氧终止法分析了相当于RNA 2 5′端250bp的cDNA酶切片段,表明与国外典型株有十分相似的一级结构。     

Tissue-specific regulation of rat estrogen receptor mRNAs

The estrogen receptor (ER) is present in a wide variety of mammalian tissues and is required for physiological estrogen responses, including estrogen-induced tissue-specific changes in gene expression. We studied the estrogen regulation of the mRNAs encoding the ER in rat uterus, liver, and pituitary. Ovariectomized (21-28 day post surgery) female CD-1 rats were injected daily with 17 beta-estradiol (E2, 10 micrograms/100 g BW) for 0, 1, or 4 h, 1, 3, or 7 days and compared with intact controls. Steady-state levels of ER mRNA were quantified using a human ER cDNA probe. Only one hybridizing species of approximately 6.2 kilobase (kb) was detected in uterine and liver RNA, similar to that observed in MCF7 human breast cancer cells. However, the ER mRNA regulation by E2 differed in direction depending on the tissue examined. In uterus, ER mRNA increased 3- to 6-fold after ovariectomy, and returned to intact levels within 24 h of E2 replacement. In contrast, liver ER mRNA declined 1.5- to 3-fold after ovariectomy and returned to intact levels after 1-3 days of E2. In pituitary tissue two hybridizing forms of ER mRNA were observed, with one species migrating at 6.2 kb, equivalent to the form in other tissues, and a second smaller species at approximately 5.5 kb. The lower molecular weight species varied somewhat in abundance from animal to animal, averaging about 20% of the intensity of the 6.2 kb band. The ER mRNA forms were regulated positively with E2.(ABSTRACT TRUNCATED AT 250 WORDS)     

EGFR expression and EGF stimulation of proliferation in human liver carcinoma cells

Epidermal growth factor receptor (EGFR) gene expression and growth stimulation of EGF on human hepatoma cells of cell lines BEL-7404 and SMMC-7721 were studied. 125I-EGF binding assay was used to measure the binding characteristics and the amounts of EGFR on these cells. The binding time course and the binding competition assay showed that the binding of 125I-EGF to 7404 cells was saturable and specific. Scatchard analysis of EGF binding curve indicated that 7404 and 7721 cells expressed approximately 1.1 x 10(5) and 0.7 x 10(5) EGFRs per cell with binding affinity (Kd) 2.1 nM and 1.8 nM respectively. Northern hybridization and immunoblotting analysis showed the EGFR gene expression products in 7404 and 7721 cells were 5.6 Kb mRNA and 170 Kilo-dalton glycoprotein. Anchorage-dependent growth of 7404 and 7721 cells was stimulated in the presence of nanogram quantities of EGF in medium containing 10% calf serum or 0.5% calf serum. The factors in serum appeared to act synergitically in stimulating of cell proliferation. EGF also stimulated the anchorage-independent growth of 7404 and 7721 cells in soft agar. The results suggest that EGFR is actively expressed in human hepatoma 7404 and 7721 cells and EGF may be one of the mitogens needed for the growth of hepatoma cells.     

甘蔗叶不同部位ATP酶活性细胞化学定位

甘蔗叶片,叶鞘和肥厚带韧皮部 ATP 酶活性定位于筛管、伴胞的质膜、内质网和某些伴胞细胞基质、小囊泡和发育成熟的液泡上;叶片韧皮部薄壁细胞、厚壁细胞和厚壁通道细胞质膜及小囊泡中亦显示有 ATP 水解产物;维管束鞘细咆与厚壁细胞或厚壁通道细胞所构成的细胞间隙上也存在有 ATP 酶活性反应产物沉淀。甘蔗叶片大、中、小三种维管束,从小维管束到大维管束,面向细胞间隙的细胞表面上的 ATP 酶活性逐渐增强,而维管束鞘细胞质膜上的 ATP 酶活性则趋于减弱;同一维管束内则以韧皮部细胞的 ATP 酶活性最强。维管束鞘细胞与叶肉细胞之间存在很多的胞间连丝,并表现出高的 ATP 酶活性。讨论了 ATP 酶活性的分布状态与叶肉细胞的光合产物向韧皮部运输的关系。