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Biomedical subjects

M Wei

Publications and source records attributed to M Wei.

123 records · Page 7Linked to original sources
PubMed1993

[Optimum sample size in the crossing experiments].

Crossing experiments are time-consuming and costly, hence, it is very essential to make a through plan and provide the necessary and sufficient sample size in advance. The common formula of the sample size in statistics is not suitable for the crossing experiments. This paper discussed two cases and put forward a corresponding estimate formula of sample size for crossing experiments, by utilizing the sample size derived from the estimate formula to arrange the crossing experiments; thus the total experimentation cost could be reduced to the lowest, or the total number of tested livestocks may be the fewest under the precondition of satisfying the requirements of the experiment designer.

Costs and Cost Analysis↗
PubMed1992

Localized membrane depolarizations and localized calcium influx during electric field-guided neurite growth.

Our study explores the mechanisms behind neurite galvanotropism. Using phase, differential interference contrast and ratiometric fluorescence microscopy, we reveal four responses of N1E-115 mouse neuroblastoma cells to 0.1-1.0 mV/microns uniform DC electric fields: cathode-directed neurite initiation and elongation, cathode-biased growth cone filopodial protrusions, transient cathode-localized calcium increases, and persistent cathode-localized membrane depolarizations. These newly demonstrated events are temporally and spatially correlated, suggesting that they are causally related. The calcium increases are prevented by calcium channel blockers and by the removal of extracellular calcium. We therefore propose that the observed field-induced membrane depolarizations activate voltage-dependent calcium channels, resulting in cathode-localized calcium influx. This, in turn, may initiate the observed cathode-biased growth cone filopodial protrusions, followed by the cathode-directed neurite elongation.

Animals↗
PubMed1992

[Estimation of genetic parameters by using analysis of variance within unit].

In the estimation of heritability, various non-genetic factors must be excluded from the variance of sire or dam. The methods of sib correlation within unit, suggested by professor Sheng Zhilian is commonly used in China. This paper will provide evidence to verify this method theoretically and discuss the application of the method to systematic classification. In addition, in this paper the author suggest some other methods to estimate heritability by using analysis of variance within unit when the blood relationship exists between sire and dam. These methods not only make the estimation procedure of hertability simple but also have the same function of analyzing variance with multiple factors.

Analysis of Variance↗
PubMed1990

[Effects of longevity-antihypertensive-mixture on essential hypertension and left ventricular hypertrophy].

A study which enrolled 65 middle-aged and elderly essential hypertensive patients with Kidney-deficiency pattern was carried out to evaluate the effects of Longevity-Antihypertensive-Mixture (LAM). As LAM was composed of Kidney-tonifying herbs, all the subjects chosen fell into the pattern of Kidney-deficiency in TCM. The subjects were randomized into two groups: The LAM group had 34, and the control group taking Apocyhum Venetum L. Fluid (AVLF) 31. The duration of medication was 12 weeks. The main results were as follows: (1) At the end of week 4, the supine systolic blood pressure (SBP), diastolic blood pressure (DBP) and mean blood pressure (MBP) in LAM group declined from 171 +/- 16 (mmHg, the same below), 101 +/- 6 and 127 +/- 7 to 153 +/- 12, 93 +/- 7 and 113 +/- 7 respectively. At the end of week 12, the supine SBP, DBP and MBP were 151 +/- 14, 93 +/- 6 and 112 +/- 8. There was significance of difference in the reduction of supine blood pressure compared with baseline (P less than 0.001). AVLF produced similar changes in the reduction of supine SBP, DBP and MBP. However, the magnitude of reduction in SBP and MBP was smaller than those with LAM (P less than 0.001). (2) There was no significance of difference in attaining goal blood pressure between LAM and AVLF groups (P greater than 0.05). At the end of week 4, 79.41% and 77.42% were achieved respectively; at 12, 79.41% and 80.65%. (3) LAM had stronger effect on relieving symptoms of essential hypertension and Kidney-deficiency than AVLF (P less than 0.05). (4) In LAM group the left ventricular mass index (VMI) decreased from 114.75 +/- 42.40 g/m2 to 100.39 +/- 36.08 g/m2 (P less than 0.001). The LVMI in AVLF group increased from 117.27 +/- 36.90 g/m2 to 117.68 +/- 38.37 g/m2 (P greater than 0.05). The results supported the therapeutic principle of TCM: Treating patients according to their pathophysiological patterns.

Cardiomegaly↗
PubMed1987

Cardiac tamponade in rheumatoid arthritis. Successful treatment with intrapericardial steroid administration.

Cardiac tamponade complicated by classic rheumatoid arthritis was markedly alleviated by pericardiocentesis and intrapericardial administration of steroid. For the following 2 years, no recurrence of cardiac tamponade or constrictive pericarditis was observed. According to the literature, only one other patient with cardiac tamponade complicating rheumatoid arthritis (RA) had been successfully treated patient by intrapericardial steroid administration.

Adult↗
PubMed1982

Chlorination of taurine by human neutrophils. Evidence for hypochlorous acid generation.

The model hydrogen peroxide-myeloperoxidase-chloride system is capable of generating the powerful oxidant hypochlorous acid, which can be quantitated by trapping the generated species with the beta-amino acid, taurine. The resultant stable product, taurine chloramine, can be quantitated by its ability to oxidize the sulfhydryl compound, 5-thio-2-nitro-benzoic acid to the disulfide, 5,5'-dithiobis(2-nitroben-zoic acid) or to oxidize iodide to iodine. Using this system, purified myeloperoxidase in the presence of chloride and taurine converted stoichiometric quantities of hydrogen peroxide to taurine chloramine. Chloramine generation was absolutely dependent on hydrogen peroxide, myeloperoxidase, and chloride and could be inhibited by catalase, myeloperoxidase inhibitors, or chloride-free conditions. In the presence of taurine, intact human neutrophils stimulated with either phorbol myristate acetate or opsonized zymosan particles generated a stable species capable of oxidizing 5-thio-2-nitrobenzoic acid or iodide. Resting cells did not form this species. The oxidant formed by the stimulated neutrophils was identified as taurine chloramine by both ultraviolet spectrophotometry and electrophoresis. Taurine chloramine formation by the neutrophil was dependent on the taurine concentration, time, and cell number. Neutrophil-dependent chloramine generation was inhibited by catalase, the myeloperoxidase inhibitors, azide, cyanide, or aminotriazole and by chloride-free conditions, but not by superoxide dismutase or hydroxyl radical scavengers. Thus, it appears that stimulated human neutrophils can utilize the hydrogen peroxide-myeloperoxidase-chloride system to generate taurine chloramine. Based on the demonstrated ability of the myeloperoxidase system to generate free hypochlorous acid we conclude that neutrophils chlorinate taurine by producing this powerful oxidant. The biologic reactivity and cytotoxic potential of hypochlorous acid and its chloramine derivatives suggest that these oxidants play an important role in the inflammatory response and host defense.

Cells, Cultured↗
PubMedDate not supplied

Imprinting of PEG1/MEST isoform 2 in human placenta.

The PEG1 gene (a.k.a. MEST) is expressed in human placental trophoblast and endothelium, and data from knockout mice show that this gene regulates placental and fetal growth. Isoform 1 of PEG1 mRNA initiates from exon 1c and produces the long form of the MEST protein. This isoform is imprinted, with expression only from the paternal allele in many human and mouse organs, including placenta. In contrast, PEG1 isoform 2, initiating from exon 1a and producing the short form of MEST protein, is biallelically expressed (non-imprinted) in several non-placental organs. Here we show that PEG1 isoform 2 is in fact imprinted in a large subset of human placentae. A CpG island overlapping PEG1 exon 1a is unmethylated in various fetal and adult non-placental tissues, but is often substantially methylated in the placenta, with the extent of methylation in a large series approximating a normal distribution. Bisulfite conversion/sequencing indicates that the inter-individual differences reflect the relative representation of heavily methylated vs. unmethylated alleles, and RT-PCR/RFLP analysis shows strongly biased allelic expression of PEG1 isoform 2 mRNA in a majority of placentae with a high proportion of methylated alleles. These data highlight PEG1 isoform 2 as a marker for future studies of inter-individual epigenetic variation and its relation to placental and fetal growth in humans.

Adult↗
PubMedDate not supplied

Sedentary habits, health, and function in older women and men.

PURPOSE: To evaluate the relation of physical activity and cardiorespiratory fitness to morbidity, mortality, and functional limitations in older persons. DATA SOURCES: We reviewed published reports related to the review's purpose. Sources were identified from recent major reports and position statements from scientific and public health organizations, our files, and reference lists of published papers. STUDY INCLUSION AND EXCLUSION CRITERIA: We included prospective epidemiological studies and clinical trials published in the peer-reviewed literature that included data from age groups of people 60 years and older. We evaluated study methods and included studies that used valid measures of exposures, clearly specified outcomes, and controlled for confounders. DATA EXTRACTION METHODS: We extracted by detailed review data on sample characteristics, outcomes, and rates and relative risks. DATA SYNTHESIS: Extracted data were included in tables, figures, or the text and were synthesized by nonquantitative methods. MAJOR CONCLUSIONS: Active and fit individuals were at much lower risk for morbidity, mortality, and loss of function when compared with sedentary and unfit persons. Data from the studies generally conformed to a steep inverse dose-response gradient across activity or fitness categories. Results were consistent, temporally appropriate, strong, and graded, and therefore support a causal hypothesis that a fit and active way of life improves health and function in older individuals.

Activities of Daily Living↗