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Biomedical subjects

M Wang

Publications and source records attributed to M Wang.

At least 847 records · Page 47Linked to original sources

Establishment of a human retinal cell line by transfection of SV40 T antigen gene with potential to undergo neuronal differentiation.

Recently, a number of laboratories have been interested in developing cell lines of ocular tissues to understand the pathogenesis of ocular diseases. Toward this end, we report here the generation of cell lines of human retina by transfection of simian virus SV40 T antigen gene. Established retinal cells grow as a monolayer and exhibit limited serum dependence. Phase-contrast and electron microscopic studies revealed distinct morphological cell types. Immunofluorescence studies showed that the established retinal cells were positive for neuron-specific enolase, neurofilament protein, glycine receptor, synaptophysin, and secretogranin. Cells were negative for glial fibrillary acidic protein, glutamine synthetase, galactocerebroside, and carbonic anhydrase II. In addition to neuronal features, a small percentage of flat cells were, however, positive for cellular retinaldehyde binding protein, and cells with the phenotype of rod and cone photoreceptor coexpressed opsin and interphotoreceptor retinoid-binding protein. An important feature of this cell line is that addition of phorbol ester and cAMP induced dramatic changes, with 100% of the cells extending long, thin neuritic processes. Thus, the established retinal cells would be useful for studies dealing with differentiation and plasticity of the cells of the nervous system.

Antigens, Polyomavirus Transforming↗

Hemorrhagic fever with renal syndrome: relationship between pathogenesis and cellular immunity.

After phenotype analysis of peripheral blood mononuclear cells (PBMC), soluble interleukin-2 receptor (sIL-2R) levels in plasma or sera from patients with hemorrhagic fever with renal syndrome (HFRS) were measured. The results showed the ratio of activated antigen (CD25, TLiSA1, CD71, and Ia)-positive lymphocytes of PBMC in the acute phase of HFRS was higher than that in convalescent phase. Moreover, there was much higher expression of heteromorphologic lymphocytes than of small lymphocytes. Decreases in T lymphocytes and CD4:CD8 ratios were seen with increases in B lymphocyte ratios and interferon-gamma (IFN-gamma) expression on PBMC surfaces in the acute phase of HFRS. IFN-gamma-positive lymphocytes included CD4, CD8, and CD56 subsets. sIL-2R levels were much higher in sera and plasma in the acute phase, especially the oliguric phase. These findings suggest that patients with HFRS are in a state of high-level cellular immune response, which may be involved in the development of inflammation and pathologic lesions.

Acute Disease↗

Serum immunoglobulin G subclass concentrations in periodontally healthy and diseased individuals.

Patients with localized juvenile periodontitis (LJP) often have high titers of antibody reactive with the serotype-specific immunodominant carbohydrate antigen of Actinobacillus actinomycetemcomitans serotype b. The vast majority of this A. actinomycetemcomitans serotype b-specific antibody is immunoglobulin G2 (IgG2). The present study was undertaken to determine whether the overall total levels of IgG2 in the sera of LJP patients are elevated. LJP patients and nonperiodontitis (NP) controls matched for age, race (black and white), and gender were studied. Additional controls included patients with adult periodontitis (AP) and patients similar in age to LJP patients but with the more-severe, generalized form of early-onset periodontitis (SP). Sera from over 700 periodontally characterized subjects were examined by using radial immunodiffusion to quantitate IgG2 as well as IgG1, -3, and -4, which were included for comparison. Serum IgG2 levels increased with age, and this was most dramatic around puberty. Black subjects in all periodontal groups had nearly 1 mg more IgG2 per ml than their white counterparts. Serum IgG2 levels were elevated (about 30 to 40%) in LJP patients of both races compared with their age- and race-matched NP controls (P < 0.01). In contrast, SP patients and AP patients had IgG2 levels comparable to their age- and race-matched NP controls. No other IgG subclass concentration correlated with periodontal diagnosis except for IgG3, which was elevated in white LJP patients. We reason that the high levels of serum IgG2 in LJP may be helpful in localizing periodontal destruction.

Adult↗

Cardiovascular regulation in humans in response to oscillatory lower body negative pressure.

The frequency response characteristics of human cardiovascular regulation during hypotensive stress have not been determined. We therefore exposed 10 male volunteers to seven frequencies (0.004-0.1 Hz) of oscillatory lower body negative pressure (OLBNP; 0-50 mmHg). Fourier spectra of arterial pressure (AP), central venous pressure (CVP), stroke volume (SV), cardiac output (CO), heart rate (HR), and total peripheral resistance (TPR) were determined and first harmonic mean, amplitude, and phase angles with respect to OLBNP are presented. AP was relatively well regulated as demonstrated by small oscillations in half amplitude (3.5 mmHg) that were independent of OLBNP frequency and similar to unstressed control spectra. Due to the biomechanics of the system, the magnitudes of oscillations in calf circumference (CC) and CVP decreased with increasing frequency; therefore, we normalized responses by these indexes of the fluid volume shifted. The ratios of oscillations in AP to oscillations in CC increased by an order of magnitude, whereas oscillations in CVP to oscillations in CC and oscillations in AP to oscillations in CVP both tripled between 0.004 and 0.1 Hz. Therefore, even though the amount of fluid shifted by OLBNP decreased with increasing frequency, the magnitude of both CVP and AP oscillations per volume of fluid shifted increased (peaking at 0.08 Hz). The phase relationships between variables, particularly the increasing lags in SV and TPR, but not CVP, indicated that efferent responses with lags of 5-6 s could account for the observed responses. We conclude that, at frequencies below 0.02 Hz, the neural system of humans functioned optimally in regulating AP; OLBNP-induced decreases in SV (by as much as 50%) were counteracted by appropriate oscillations in HR and TPR responses. As OLBNP frequency increased, SV, TPR, and HR oscillations increasingly lagged the input and became less optimally timed for AP regulation.

Adult↗

History of medicine and nephrology in Asia.

The beginning of Chinese medicine has been attributed to 3 mythical emperors who gathered herbs for medicines. During the 2nd century BC, Han dynasty physicians developed cranial trephining and sedation with wine and herbs for anesthesia. Chiang Chung-Ching (142-212 AD) used the appearance of rashes in diagnosis, treated infections with anthelmintics and asthma with ephedra, described the symptoms of diabetes mellitus and expanded medical ethics. The specialties of obstetrics, pediatrics, ophthalmology and dentistry were described in the records of the Han and Tang dynasties, and methods of setting fractures and treating trauma were comparable with those of Roman military doctors. Shen Tua (1031-1095 AD) compiled a pharmacopeia and studied acupuncture and the pulses. Forensic medicine was developed during the 10th century by Sung Tse, who also advocated hand washing with sulfur and vinegar to avoid infection during autopsies. The Daoist physicians used androgens and estrogens to treat hypogonadism with therapeutic preparations of placentas. They also had an advanced knowledge of alchemy, claiming to achieve 'immortality' by their preservation techniques. Qualifying examinations for physicians were conducted by the Chinese state as early as the 1st century AD, and later incorporated philosophy and art to conform with the Confucian ideal. Throughout these eras, Chinese medicine profited from contact with western Asia. In ancient Chinese medicine, the excretory function of the kidney was attributed to the bladder. 'Kidney weakness', which refers to somatized depression, was treated by acupuncture along the 'kidney channel'. Pulse examination was also used to give a measure of the imbalance of renal Yin and Yang.(ABSTRACT TRUNCATED AT 250 WORDS)

Alchemy↗

The LIM domain homeobox gene isl-1: conservation of human, hamster, and rat complementary deoxyribonucleic acid sequences and expression in cell types of nonneuroendocrine lineage.

The LIM domain homeobox gene isl-1 was originally isolated by virtue of its ability to bind DNA sequences from the 5'-flanking region of the rat insulin gene. Initial experiments localized isl-1 to the islet cells of the pancreas, suggesting a possible role for this protein in the regulation of insulin gene expression and/or islet cell development. More recent studies have determined that isl-1 is also expressed in the central and peripheral nervous system. We now report that isl-1 gene expression is not restricted to cells of neuroendocrine lineage. Northern blot analysis of rat and hamster fibroblasts, rat keratinocytes, and human epidermoid carcinoma cells detected messenger RNA transcripts that hybridized, at high stringency, to different isl-1 complementary DNA probes. DNA sequence analysis of human and hamster isl-1 complementary DNAs generated by reverse transcription-polymerase chain reaction from nonneuroendocrine cell lines demonstrated 100% conservation of isl-1 amino acid sequences from rat hamster and human species. Western blot analysis with isl-1 antiserum demonstrated that immunoreactive isl-1 was detectable in nuclear extracts from islet cell lines. In contrast, immunoreactive isl-1 was only detected in cytoplasmic extracts from nonneuroendocrine cell lines. The results of these studies demonstrate striking conservation of mammalian isl-1 coding sequences and widespread expression of the isl-1 gene in heterologous cells. These experiments suggest that the biological importance of isl-1 may not be restricted to neuroendocrine cell lineages and raise the possibility that isl-1 function may be regulated by sequestration in distinct cellular compartments.

Amino Acid Sequence↗

The G gamma:A gamma ratios in the fetal hemoglobin of newborns of the Man ethnic group and their gamma-globin gene arrangements.

The G gamma:A gamma ratios of Hb F were determined in 331 newborn babies of the Man ethnic group in Liaoning Province, P.R. China, using polyacrylamide gel electrophoresis; in 27 cases they were also determined by reversed phase high performance liquid chromatography. The results showed that a high G gamma value (> 80%) was present in four cases (1.21%) and low G gamma values (30-48%) in six cases (1.81%); not a single case with the A gamma T [A gamma 75(E19)Ile->Thr] chain was found. Gene mapping analysis demonstrated that two babies with high G gamma values had the -G gamma-G gamma-/-G gamma-A gamma- (0.60%), and two others the -G gamma-AG gamma-A gamma-/-G gamma-A gamma- (0.60%) arrangements. Two of the four babies with low G gamma values were identified as -A gamma-A gamma-/-G gamma-A gamma- (0.60%) and the other two as -GA gamma-/-G gamma-A gamma- (0.60%). The genotype -A gamma-A gamma- has not been reported before in Chinese.

Asian People↗

Measuring and predicting the effects of alcohol consumption on contrast sensitivity for stationary and moving gratings.

Contrast sensitivity was measured for 12 healthy young males while sober, after ingestion of an alcohol placebo, and after ingestion of alcohol (95% grain alcohol; mean estimated blood alcohol level = .088%). Observations were made for both stationary gratings and gratings that traveled through a circular path and required pursuit eye movements. The significant alcohol-related reduction in contrast sensitivity was 2.6 times greater for moving (.29-log-unit reduction) than for stationary gratings (.11-log-unit reduction). The loss in contrast sensitivity for the moving gratings of high spatial frequency (12 cpd) was particularly severe (.37 log unit). Estimated blood alcohol level was correlated with the loss in contrast sensitivity for moving gratings (r = .61), but not with the loss for stationary gratings. Estimated blood alcohol level was strongly correlated with the difference between the loss in contrast sensitivity to moving and stationary gratings (r = .75). These results are consistent with reports that alcohol consumption degrades the ability to make pursuit eye movements. Subjects' perceived intoxication level was not a reliable predictor of any index of visual performance.

Adult↗

Precocious IRBP gene expression during mouse development.

PURPOSE: To determine if the time course for the onset of gene and protein expression for interphotoreceptor binding protein (IRBP) precedes that of opsin in the developing mouse retina. METHODS: Relative mRNA levels of the IRBP and opsin genes were determined in prenatal and postnatal retinal RNA with RNase protection analysis (RPA). To determine if IRBP and opsin protein expressions are differentially regulated, dissociated retinal cells from postnatal (P) days 2 and 3 mice, that were injected with BrdU, were then double-labeled with antibodies against BrdU and either opsin or IRBP. RESULTS: With RPA, IRBP mRNA was detected on embryonic (E) day 11 at the time of cone formation, whereas opsin mRNA was not detected until P0. It took until P3 for opsin expression to reach significant levels, whereas rods already appear during embryonic development. IBRP transcription preceded that of opsin because it rapidly increased from E13 to an early postnatal day. By P20, the expression levels of IRBP and opsin achieved constancy. Double antibody labeling revealed positive staining for both IRBP and BrdU as soon as 2 hours after injection, but it took until 40 hours for double positive staining for opsin and BrdU. CONCLUSION: Because only IRBP protein expression was observed before the last mitosis of the photoreceptor precursor cells, IRBP could be essential for retinal development.

Actins↗

[Isolation and purification of glyceraldehyde-3-phosphate dehydrogenase from Schistosoma japonicum].

This paper recommends a simple and easy method to isolate and purify glyceraldehyde-3-phosphate dehydrogenase (GAPDH) from Schistosoma japonicum with electrophoretic purity. The recovery rate of 56.1% of glyceraldehyde-3-phosphate dehydrogenase from S. japonicum extract was achieved by ammonium sulfate precipitation, DEAE-cellulose column chromatography and SDS-PAGE. Using SDS-PAGE, the presence of one major band in the final purified GAPDH preparation was demonstrated. This protein had a MW of 37 kDa. The authors discuss the important functions of GAPDH and suggest that this method may be useful in the research of the protective immunity of S. japonicum GAPDH in the development of schistosome vaccine.

Animals↗

[Pharmacokinetics and bioavailability study on acetaminophen oral drop in healthy volunteers].

The concentrations of acetaminophen in human plasma were determined by RP-HPLC after administration of a single oral dose of 1000 mg acetaminophen oral drop or tablet to eight normal male volunteers in a crossover study. The concentration vs time curves of acetaminophen all fitted the two compartment model. The Cmax in oral drop and tablet were 11.23 +/- 0.93 and 8.79 +/- 0.93mg/L, respectively; Tmax were 0.86 +/- 0.08 and 1.48 +/- 0.39h; T1/2 beta 3.03 +/- 0.79 and 2.51 +/- 1.10 h; AUC 42.35 +/- 6.20 and 40.60 +/- 6.79mg/L.h. When AUC in tablet was 100%, the relative bioavailability of acetaminophen oral drop was 105.58%. The results showed that the oral drop and tablet are bioequivalent.

Acetaminophen↗

Predictors for wound healing in ischemic lower limb amputation.

Determination of the level of amputation of an ischemic lower limb presents a difficult problem. This prospective study evaluated parameter capable of predicting wound healing in patients with peripheral vascular disease. Forty-four amputations performed on 38 patients for advanced ischemia of a lower extremity were analyzed. Among them, 20 patients had diabetes mellitus and 10 received vascular reconstruction prior to the amputation. All patients except one had a skin temperature measurement and 26 patients had segmental blood pressure measurements before amputation. Of the 44 amputations, 31 healed successfully and 13 failed to heal without further intervention. Patients who had an amputation above the ankle joint had a significantly better outcome than those who had amputation below the ankle joint. Among the amputations proximal to the ankle joint, all patients with segmental blood pressures > 70 mmHg at the amputation level had successful wound healing, compared with only half of those patients with segmental pressures < 70 mmHg. However, ankle segmental pressure was not associated with the outcome of wound healing in the amputations distal to the ankle joint. The absolute skin temperature and the difference between the skin and ambient temperature were found to be poor predictors for wound healing. No significant differences were detected among the successes and failures with regard to the patient's sex, age, blood chemistry and duration of diabetes mellitus.

Adult↗

Potential role of ascorbic acid and beta-carotene in the prevention of preterm rupture of fetal membranes.

The association of antioxidant vitamins in serum and amniotic fluid with preterm rupture of fetal membrane (PROM) was examined. Amniotic fluid and venous blood specimens from 80 pregnant women with or without PROM were analyzed for ascorbic acid (ASA), alpha-tocopherol, retinol and beta-carotene concentrations. No differences in retinol and alpha-tocopherol in amniotic fluid or serum concentrations were found between the PROM and control groups. PROM and control subjects had similar serum ASA concentrations. However, PROM subjects had lower amniotic fluid ASA concentrations (p < 0.0001) and lower ratios of amniotic fluid ASA to serum ASA concentration than those of controls. Serum beta-carotene levels were lower in PROM group than control group (p = 0.025). The findings suggest that a low level of ASA in amniotic fluid but not serum appears to be an important determinant of PROM. beta-Carotene and ASA may act synergistically to prevent PROM in smokers.

Adult↗

Immunoassays of the metalloproteinase (MMP-2) and tissue inhibitor of metalloproteinase (TIMP 1 and 2) levels in noninvasive and metastatic PC-3 clones: effects of taxol.

We have selected and subcloned bone metastatic (PC-3 ML) and noninvasive, nonmetastatic (3 x N.I.) lines from human prostatic PC-3 parent cells. In this paper, we have compared relative levels of MMP-2 and TIMP-1 and 2 in PC-3 tumors grown in severe combined immunodeficient or SCID mice. Dot blots with polyclonal antibodies specific for MMP-2, TIMP-1 and TIMP-2 revealed that the MMP-2 levels were high in subcutaneously grown PC-3 ML clones but low in 3 x N.I. clones at days 20 and 40. The TIMP-1 levels were inversely proportional to MMP-2 in the two types of clones, respectively. The TIMP-2 levels were similar in both clones at days 20 and 40. Gelatin zymograms confirmed that PC-3 ML tumors contained MMP-2 (and not MMP-9) subcutaneously or in bone metastases in SCID mice. Slot blots of PC-3 ML bone tumors comparing MMP-2 and TIMP-1 levels showed at days 10, 15, 17, 19, 21, and 25 that the ratio of MMP-2 to TIMP-1 increased, especially at about day 21, when extensive secondary metastases to the peritoneal cavity occurred. The levels of TIMP-2 remained constant. Quantitative ELISAs confirmed the blotting data and showed that taxol blocked MMP-2 but not TIMP-1 production in these advanced tumors. We conclude that highly metastatic PC-3 ML variants contained relatively high levels of MMP-2 and low amounts of TIMP-1.

Animals↗

Connection ensemble model of local neural circuits.

A connection ensemble model (CEM) of local neural circuits in central nervous system (CNS) is proposed in this work. Neuronal interactions are investigated at two levels, i.e. the synaptic connection between single neurons and the macro-connections between different neuronal groups. The efficacy of macro-connection is quantitatively determined by the efficacies of constituent synapses, and is asymptotically stable. This model provides a reasonable description for the functional invariance of local neural circuits with structural diversities, which is a widely observed fact in neurobiology. It is expected that the works in CEM model would enrich the current research in neural dynamics.

Animals↗

[Chemical constituents of flower of David lily].

Three compounds were isolated from the flower of Lilium devidii. On the basis of chemical reaction, UV, MS, 1HNMR and 13CNMR spectral data, they were identified as beta-sitosterol, stigmasterol and emodin. These compounds are obtained from the plant for the first time.

Drugs, Chinese Herbal↗