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Biomedical subjects

S Shi

Publications and source records attributed to S Shi.

At least 127 records · Page 7Linked to original sources
PubMed1991

Chemical synthesis, cloning and expression of human epidermal growth factor gene in Saccharomyces cerevisiae.

A gene coding for human epidermal growth factor (hEGF) has been chemically synthesized by solid-phase phosphoramidite method. The 173 base-pair synthetic DNA duplex consists of a structural gene encoding hEGF, a stop codon TGA at 3' end and some convenient restriction sites at both ends of the gene. The synthesis of the gene involved enzymatic joining of 8 oligonucleotides to form a DNA duplex which was cloned into vector M13mp18. The recombinant colonies were identified by dot hybridization and restriction enzyme digestion. Its accuracy was confirmed by DNA sequence analysis. The hEGF DNA was inserted into yeast secretory vector YFD59. The resulting expression plasmid YFD104 was introduced into yeast Saccharomyces cerevisiae. The binding assay showed that the yeast transformants could express and secrete hEGF.

Amino Acid Sequence↗
PubMed1991

[A study on the secondary infection in families in which hepatitis A patients were isolated and treated in hospitals and those in which patients stayed at home].

This study was conducted during the epidemic season in Hang Zhou, zhejiang in the spring of 1988. HAV infection rates were compared between close contacts of the hepatitis A patients isolated in hospitals and those stayed at home. It was found that there was significant difference between the HAV infection rates in the group of close contacts of hepatitis A patients who have been hospitalized within 5 days and those in the group stayed at home or those in other groups. Whereas the HAV infection rates in the group of close contacts of HA patients remained at home were not significantly different from those in other groups. The results showed that HA patients had to be isolated and treated in hospital early. HAV inapparent infection rate was 86.21% in this study. The ratio between HAV apparent infection and inapparent infection was 1:6.25.

Adult↗
PubMed1991

[Chemical constituents of Morinda officinalis How].

This paper reports the identification of four compounds isolated from the cortex of Morinda officinalis growing in Guangdong Province. These compounds are beta-sitosterol (I), 2-methyl-anthraquinone(II), rubiadin-1-methyl ether(III) and 24-ethylcholesterol(VI). Compounds II and VI are isolated from Morinda Genus for the first time.

Anthraquinones↗
PubMed1990

[Effects of the combination of aspirin and nifedipine on platelet aggregation and thrombogenesis].

The effects of nifedipine (Nif), aspirin (ASA) and ASA + Nif on platelet aggregation and generation of thrombosis were studied. Both ASA and Nif inhibited rabbit platelet aggregation in vitro and rat platelet aggregation in vivo induced by ADP, also prolonged the occlusion time of thrombosis induced electrically in the carotid artery of the rat and reduced the death rate resulting from pulmonary thrombosis induced by i.v collagen and epinephrine in mice. The above effects were markedly increased when Nif and ASA were used in combination. All the above effects were dose-dependent.

Animals↗
PubMed1990

[The natural foci of the tsutsugamushi disease in the suburbs of Hang Zhou City].

In 1986, investigating tsutsugamushi disease in the suburbs of Hangzhou, We isolated Rickettsia tsutsugamushi from leptotrombidium gaohuense and its reservoir hosts, Rattus confucianus and Rattus fulvescens, which were collected in Yang Shan Wu village, Linan county. It proved there was a natural focus of tsutsugamushi disease in the suburbs of Hang zhou. Which is located at 30 degrees 35'. North latitude, and main forest of the East Tianmu Mountain, covered by wide and needle leaves, with more wide leaves than needle one. The vector is leptotrombidium gaohuense. The host are Rattus confucianus and fulvescens. Such focus belongs to inland-mountain type.

Adult↗
PubMed1990

Aldose reductase mRNA is an epithelial cell-specific gene transcript in both normal and cataractous rat lens.

Aldose reductase (AR) is implicated in the development of sugar cataracts by its reduction of galactose or glucose to polyols. The authors' recent work suggested that AR mRNA is found to be expressed in high concentrations in rat-lens epithelial cells after exposure of the animal to a diet containing 50% galactose. They localized the AR mRNA in the lens cells by in situ hybridization with a previously described AR clone. The data establish that AR mRNA is apparently an epithelial and not a fiber-cell gene transcript. It accumulates in the epithelial cell, then it is carried into the newly differentiated fiber cell, and finally it concentrates in the posterior region of the matured fiber cell. The AR mRNA is found in all of the anterior epithelial cells including the equatorial and central epithelia. It is present at highest concentrations in the elongating epithelial cells, and it is distributed equally throughout the secondary fiber cells at the bow, with no indication of a preferential buildup of AR mRNA in any of the nucleated fiber cells in the cortex. This differs from what the authors reported to occur with MP26 mRNA, a fiber cell-specific gene transcript. They found that MP26 mRNA was absent from the epithelial cells but was preferentially found in the secondary fiber cells. Present data suggest that the increase in AR mRNA concentration observed to occur in cataractous lenses is a result of epithelial cell proliferation, where every cell appears to be competent in expressing AR mRNA. The results of this research imply that AR mRNA is a lens epithelial cell-specific gene transcript in both normal and cataractous lenses.

Aldehyde Reductase↗
PubMed1990

[Study on protein polymorphism of Chinese KM subcolonies].

This paper presents the results of study on 24 protein markers by means of electrophoresis in 4KM subcolonies maintained in Beijing, Shanghai and Changcun, and compares it with that of one NIH colony introduced from U.S.A. in 1982. The results revealed that: (1) There were few genetic variants on allelic constitutions of Chinese KM mouse colonies, and the genetic distance among KM subcolonies is 0.008-0.027 positively related with the time the colony closed; (2) The unique position of S: KM mouse was shown in phylogenetic diagram of 4 KM subcolonies, which agrees with the result from mandible analysis; (3) The allelic constitutions of KM mice differs from NIH mice a Swiss derivative colony at Es-3, Es-10, Glo-1, Gpt-1, Got-2 and Mpi-1 loci and the average genetic distance between KM and NIH colonies is 0.131 + 0.011, which indicates that Chinese KM mice is one of non-Swiss derivative subspecies.

Animals↗
PubMed1989

Relative abundance of aldose reductase mRNA in rat lens undergoing development of osmotic cataracts.

Aldose reductase (AR) messenger RNA concentration was determined in normal rat lens and in lens from rats fed a 50% galactose diet over a period of 20 days. The AR mRNA was detected by using a previously described AR cDNA clone. The relative concentration of the AR mRNA was estimated by cpm of 35S-UTP labeled antisense RNA hybridized to dot-blots prepared from cytosols isolated from single lens, decapsulated lens (cortex) and its respective capsule (epithelia). The results demonstrated that the concentration of the AR mRNA in the epithelium doubled over the 20 day period. Correspondingly, an increase in the concentration of the DNA was also observed, suggesting that the increase in epithelial cytosolic mRNA might be partially due to the increase in the number of epithelial cells occurring in lens undergoing cataractogenesis. The increase in AR mRNA in the epithelia was gradual, and it doubled by day 12 on galactose, while the increase in DNA was rapid and reached an optimum level by about day 4. By day 4 the cortex AR mRNA concentration increased, then rapidly decreased to insignificant levels by day 20. Changes in AR mRNA and in DNA following a high influx of galactose in the lens might suggest a heightened gene response to changes in the cellular environment for the lens epithelium.

Aldehyde Reductase↗
PubMed1986

The prediction and/or detection of ovulation by means of urinary steroid assays.

Twenty normally menstruating women volunteered for a study in which plasma samples were collected daily during an entire menstrual cycle. On the same days, samples of morning urine were also collected, as well as random samples of urine voided at the visit to the Outpatient Clinic. Progesterone (P), estradiol (E2) and lutropin (LH) were assayed in plasma, and pregnanediol-3-glucuronide (PdG), estrone-glucuronide (E1G), estriol-16-glucuronide (E3G), P, and E2 were measured in urine using radioimmunoassays. Progesterone in urine was assayed both with and without preceding chromatography. All urinary glucuronides and progesterone exhibited cyclic patterns similar to those of E2 or P in plasma. Seven-fold increases from early follicular to luteal phase values (for PdG and urinary P; the latter both with and without chromatography), or to peak levels (for E1G and E3G) were observed. The difference between the baseline and peak levels was less distinct (approximately 5-fold) for E2 in urine. The day-to-day coefficient of variation of early follicular phase values decreased from 40% to 25% by calculating the ratios of the glucuronides or P to creatinine (C). The peaks of estrogen glucuronides were delayed mostly by 1 day in comparison to the peaks of E2 in plasma. The urinary peaks of estrogens were in most cases more closely clustered around the day of the LH-peak when the measurements were corrected for C. For the determination of the first significant rise of steroid levels in a cycle, the calculation of a sustained rise (leading to a significant cumulative sum - CUSUM) was found superior when compared to other recommended indices, such as a 50% increase over the mean of 3 preceding values, or the increase over the baseline level plus 2 standard deviations. Sustained rises were calculated for all indices studied (including the ratio of urinary E1G to PdG). The ratio of E1G to C in morning urine gave consistently the most compact distribution of sustained rises. It is concluded that daily measurements of urinary PdG (or P) and E1G (or, possibly, E2) could substitute the serial assays of P and E2 in peripheral blood in the retrospective assessment of the ovarian functionn. The day-to-day variation can be significantly reduced, if results are expressed per concentration of C. For the prediction of ovulation or fertile period, the best index of urinary steroids appears to be the sustained rise in the ratio of E1G to C. However, this "best" method is still not good enough in terms of overall reliability and practicability.

Adult↗