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Biomedical subjects

M L Wang

Publications and source records attributed to M L Wang.

At least 55 records · Page 3Linked to original sources
PubMed1996

Blood pressure-lowering effect of fish oil is independent of thromboxane A2 level in spontaneously hypertensive rats.

Whether the alterations in the synthesis of thromboxane A2 (TXA2) is the direct mechanism underlying the blood pressure-lowering effect of fish oil was investigated in this study. Six groups of 11 male spontaneously hypertensive rats were fed semipurified diets containing corn or fish oils and graded levels (50, 5000 or 15,000 ppm) of dietary vitamin E for 8 weeks. Plasma TXA2, assayed by RIA, was significantly greater in the corn oil group than in the fish oil group (P < 0.05). Compared to 50 ppm dietary vitamin E, 5000 and 15 000 ppm dietary vitamin E, respectively, significantly decreased plasma TXA2 (P < 0.05). Systolic, mean or diastolic blood pressure, evaluated by the tail cuff method, were significantly higher in the corn oil group than in the fish oil group (P < 0.05). However, vitamin E had no effect on blood pressure. No relationship between TXA2 and blood pressure was found. Experimental results indicated that the alterations in the synthesis of TXA2 were not the direct antihypertensive effect of fish oil.

Animals↗
PubMed1996

Reconsideration of testicular biopsy and follicle-stimulating hormone measurement in the era of intracytoplasmic sperm injection for non-obstructive azoospermia?

To determine the possibility of finding motile spermatozoa and spermatids in patients with high serum follicle stimulating hormone (FSH) and spermatogenetic disorders proven by pathology, 100 cases of male infertility were reviewed. Of these, 71 patients were found to have non-obstructive azoospermia or severe primary spermatogenetic disorders, and 20 had obstructive azoospermia. A prospective study of the most recent 51 cases was conducted. Multiple testicular tissue biopsies were examined by a pathologist and a well-trained gynaecological technician. The findings of spermatozoa, spermatids and serum FSH concentrations were compared among six different histological groups. It was concluded that 51.2% of the non-obstructive azoospermic and failed spermatogenetic patients had spermatids and even motile 'shaking' spermatozoa and should be re-evaluated. In the non-obstructive azoospermic patients here, almost all the motile spermatozoa and spermatids were found in patients with a serum FSH concentration of < 30 mIU/ml. It is suggested that a testicular biopsy should be conducted in every case of non-obstructive azoospermia and spermatogenetic disorder, even in those patients with elevated serum FSH concentrations.

Biopsy↗
PubMed1996

Improvement in lung function measurements using a flow spirometer that emphasizes computer assessment of test quality.

We compared retrospective measurements of lung function from 101 steel workers using a commercially available spirometer to prospective lung function measurements performed, on average, 1.3 years later, with a newly developed spirometer. This spirometer was designed and developed to incorporate technology that provides immediate feedback on the quantitative and qualitative aspects of each forced expiratory effort. Of the 101 workers, 82 who had spirometry performed with each spirometer had at least two acceptable curves, and 51 workers tested with each spirometer had curves that met all American Thoracic Society (ATS) criteria for spirometry. No group showed the anticipated decline in forced expiratory volume in 1 second (FEV1) over time. The results showed an increased number of curves meeting ATS acceptability and reproducibility criteria, and a statistically significant increase in the FVC in all groups, and an increase in the FEV1 in the group encompassing all workers. Use of technology that strengthens the interaction between the spirometry technician, the data available to the technician on the computer, and the participant appears to represent true underlying lung function more accurately. Such an approach to the collection of lung function data should be considered by those evaluating spirometers for implementation in the workplace or pulmonary function laboratory as well as by those planning future spirometer development.

Humans↗
PubMed1996

A physical map of chromosome 2 of Arabidopsis thaliana.

A yeast artificial chromosome (YAC) physical map of chromosome 2 of Arabidopsis thaliana has been constructed by hybridization of 69 DNA markers and 61 YAC end probes to gridded arrays of YAC clones. Thirty-four YACs in four contigs define the chromosome. Complete closure of the map was not attained because some regions of the chromosome were repetitive or were not represented in the YAC library. Based on the sizes of the YACs and their coverage of the chromosome, the length of chromosome 2 is estimated to be at least 18 Mb. These data provide the means for immediately identifying the YACs containing a genetic locus mapped on Arabidopsis chromosome 2.

Arabidopsis↗
PubMed1996

Longitudinal and cross-sectional analyses of lung function in steelworkers.

We evaluated associations between dust exposure, demographic factors, and lung function by longitudinal and cross-sectional analyses in 475 steelworkers who participated in at least three spirometry tests over 5 yr between 1982 and 1991. Baseline and follow-up spirometry and changes between baseline and final follow-up assessment attributable to age, height, weight, weight gain, smoking status, pack-years, and years worked in dusty areas were examined using stepwise multiple linear regression techniques. Smoking, aging, being overweight, excessive weight gain, and dust exposure were related to a lower level and a steeper slope of decline of pulmonary function. Cigarette smoking was also an important risk factor. Dust exposure was related to the level of lung function, with a stronger effect at baseline than at follow-up. Estimated loss at baseline of FEV1, FVC, and FEV1/FVC% was 9.3, 6.4 ml, and 0.1 % per year of employment in a dusty area, respectively, whereas the association between dust exposure and longitudinal decline of lung function was weak. However, a strong relationship between weight gain and longitudinal decline of FEV1 and FVC was found. Estimated decreases in FEV1 and FVC attributable to weight gain were 4.7 and 6.3 ml per lb/yr, respectively. This work suggests that weight gain is an important determinant for longitudinal lung function decline. This large impact of weight gain in the decline of lung function in a middle-age and relatively overweight working population has not been previously reported. Additional work needs to be undertaken to show the strength of this relationship in other populations.

Adult↗
PubMed1996

Preimplantation diagnosis of alpha-thalassemia by blastomere aspiration and polymerase chain reaction: preliminary experience.

The ability to diagnose and detect the presence of debilitating and life-threatening diseases would be an invaluable asset to those involved in in vitro fertilization programs. To investigate the possibility of diagnosing severe alpha-thalassemia before implantation, DNA sequences targeting the abnormal deletion breakpoint and the normal region of the alpha-globin gene were amplified by polymerase chain reaction from blastomeres aspirated from human preimplantation embryos. Before performing this experiment, a mouse model blastomere aspiration technique was examined to confirm embryo survival and normal development capability. The mouse embryos showed undisturbed development in the five- to seven-, as well as the eight-cell stages when one, or two (eight-cell stage only) blastomeres were aspirated. The four-cell embryos had a lower survival rate but had a blastocyst formation rate comparable to the more advanced stages and the control embryos. In the human embryo experiment, no homozygous Southeast Asian alpha-thalassemia was detected in the aspirated blastomeres, although two heterozygotic alpha-thalassemia embryos were discovered. The sensitivities of targeting sequence detection in the mouse and human blastomeres were between 50% and 76% in the respective groups. This study supports the feasibility of preimplantation diagnosis of severe alpha-thalassemia when both father and mother are carriers of this inheritable disease.

Animals↗
PubMed1996

The effects of Vero cell co-culture on human zygotes resulting from in vitro fertilization and oocytes following subzonal insemination.

A variety of co-culture systems have been devised to enhance the human embryo development in vitro. Vero cells were selected because they can be highly controlled and are easy to handle. To evaluate the embryotrophic effects of Vero cell monolayers, when they were co-cultured with human in vitro fertilized zygotes or subzonal inseminated oocytes. Total 1695 two-pronuclear embryos resulting from in vitro fertilization were cultured with Vero cells or medium alone for 24 hours. Similarly, sixty-six two-pronuclear embryos resulted from subzonal insertion of sperm (SUZI) with co-culture starting immediately following SUZI were compared with fifty-two two-pronuclear embryos resulted from SUZI, without co-culture. The numbers of blastomere and morphology of embryos were compared between the co-culture group and control group using student's t-test. Cell numbers in each embryo were greater in the IVF/co-culture group than in the control group (4.01 +/- 1.32 vs. 3.86 +/- 1.45, p < 0.05). The rates of poor quality embryo with major fragmentation were lower in the co-culture group than in the control group(11.5% vs. 19.9%, p < 0.001, for IVF embryos; 9% vs. 27%, p < 0.005, for SUZI oocytes). Co-culture SUZI oocytes on Vero cells prior to fertilization did not positively influence embryo cleavage, but improved embryo quality. We conclude that Vero cells can enhance human embryo development; however, the period for one-day or two-day co-culture is too short to provide a maximal support. Short term co-culture did not increase implantation rates. Immediate co-culture following SUZI might somewhat rescue the microinseminated oocytes. However, a longer duration of co-culture is necessary to exert the maximal effects on embryo development and implantation.

Adult↗
PubMed1995

Clinical significance of admission hyperglycemia and factors related to it in patients with acute severe head injury.

BACKGROUND: Patients in the acute stage after a severe head injury often exhibit systemic stress responses. The aim of the present study is to assess in such patients the clinical significance of the change of catecholamines (CA) and of blood glucose. METHODS: The levels of serum of norepinephrine (NE), epinephrine (E), and dopamine (DA) were measured in 48 adults in the first 7 days after a severe head injury, and in 35 normal adults as a control group. The blood level of glucose at the time of admission was also measured. RESULTS: It was found that: (1) The serum CA level was significantly higher in the injured group than in controls. (2) The serum NE and E levels were higher in patients with lower Glasgow Coma Scores (GCS) and in the group of patients who did not survive. (3) The blood glucose level on admission was related both to the serum NE and E levels within the first 24 hours after head injury (r = 0.574, p < 0.05 and r = 0.410 and p < 0.05, respectively) and also the GCS and Glasgow Outcome Score (GOS) in these patients. (4) Patients with GCS of 3-4, 5-6, and 7-8 had mean glucose levels on admission of 12.805 +/- 3.205 mmol/L (228 +/- 67.23 mg/100 mL), 9.133 +/- 1.228 mmol/L, (160 +/- 12.28 mg/100 mL) and 6.029 +/- 1.228 mmol/L (107.66 +/- 21.9 mg/100 mL), respectively (p < 0.01). (5) Ninety percent of the patients with blood glucose levels of 9.6 mmol/L (171.4 mg/100 mL) at admission died within the first month; in the patients with lower glucose levels the mortality was 15%. CONCLUSIONS: These findings suggest that in the acute stage of severe head injury hyperglycemia and elevation of serum levels of CA are common components of the stress response, significant indicators of severity, and significant predictors of outcome.

Acute Disease↗
PubMed1995

Effects of vitamin E deficiency and dietary linoleate on serum thromboxane synthesis in male sprague-dawley rats.

The aim of the present study was to examine whether vitamin E deficiency and dietary linoleate had additive or synergistic effects on serum thromboxane (TX) status and therefore on thrombogenesis. Eight groups of five male weaning Sprague-Dawley rats were fed semipurified diets containing 3.5 or 18.4% of energy from linoleate (en% linoleate) and 0, 100, 5000, 15,000 ppm vitamin E for 8 weeks. Rats fed no vitamin E had the lowest serum vitamin E while rats fed 15,000 ppm vitamin E had the highest serum vitamin E (p < 0.05). Serum 18:2, n-6 (linoleic acid; LA) and 20:4, n-6 (arachidonic acid; AA) were significantly greater in the 18.4 en% linoleate group than in the 3.5 en% linoleate group (p < 0.05). Serum TXA2, measured as its stable metabolite TXB2, was significantly greater in the vitamin E-deficient rats than in the vitamin E-adequate and vitamin E-supplemented rats (p < 0.05). Serum lipid peroxidation, measured as thiobarbituric acid reactive substances (TBARS), was significantly greater in the 0 and 100 ppm vitamin E groups than in the 5000 and 15,000 ppm vitamin E groups (p < 0.05). No interaction between dietary linoleate and vitamin E deficiency on serum TX status was found. However, it seemed that vitamin E deficiency had a more potent effect on TX synthesis than dietary linoleate. The result suggested that vitamin E deficiency may be prothrombogenic via its effect on TX synthesis.

Animals↗
PubMed1995

Airway responsiveness and job selection: a study in coal miners and non-mining controls.

BACKGROUND: It has been suggested that health related job selection is a major cause of the healthy worker effect, and may result in inaccurate estimates of health risks of exposures in the working environment. Improved understanding of self selection, including the role of airway hyperresponsiveness, should improve accuracy in estimating occupational risks. METHODS: We evaluated symptoms of the respiratory tract, lung function, occupational and smoking histories, and airway responsiveness from a cross sectional survey of 478 underground bituminous coal miners and non-mining controls. Workers with abnormal spirometry were excluded from methacholine testing. RESULTS: Methacholine responsiveness (> or = 15% decline in forced expiratory volume in one second) was associated in both miners and controls with reduced ventilatory lung function and an increased risk of respiratory symptoms. Miners with the longest duration of work at the coal face had a low prevalence of methacholine responsiveness, compared with miners who had never worked at the coal face (12% v 39%, P < 0.01). Throughout their mining careers, miners who responded to methacholine were consistently less likely to have worked in dusty jobs than miners who did not respond to methacholine. CONCLUSIONS: These results provide evidence that workers who are employed in dusty jobs are less likely than their unexposed coworkers to show increased non-specific airway responsiveness, presumably as a result of health related job selection. Surveys of workers in which responsiveness data are unavailable may underestimate the effects of dust exposure on respiratory health.

Adult↗
PubMed1994

Neonatal renal venous thrombosis--a case report describing serial sonographic changes.

Neonatal renal venous thrombosis (NRVT) is a serious complication of newborns. Ultrasound is most useful in detecting NRVT. However, there is no detailed description of the evolution of ultrasound finding in NRVT. Here we report a patient with NRVT with complete ultrasound follow-up. Perivascular streaks were first seen at 3 days of age with a diffusely enlarged and echogenic right kidney. Echolucency then gradually appeared over the medulla area with shrinking renal size. Concomitant loss of renal function was evidenced by dimercaptosuccinic acid scan. The kidney became contracted at the age of 1 year. Since the pathognomonic perivascular streaks were present for only a few days, early ultrasound scanning should be performed for every newborn suspected of having NRVT.

Humans↗
PubMed1994

[The role of TNF-alpha in the growth and differentiation of U937 cells induced by PMA and IFN-gamma].

The effects of PMA and IFN-gamma on regulation of growth and differentiation of human monoblastic leukemic cell U937 were examined. U937 cells were stimulated by different concentrations of PMA and IFN-gamma respectively and NBT reduction assay was used to detect the differentiation of the cells. The results showed that both PMA and IFN-gamma dose-dependently induced differentiation of U937 cells into mature macrophage-like cells. The data also revealed a time-course response in the differentiation induction. Moreover, the U937 cell growth was significantly inhibited by the treatment of PMA and IFN-gamma. These results suggest that PMA and IFN-gamma coupled the regulation of U937 cell growth and differentiation. It was found that tumor necrosis factor-alpha (TNF-alpha) was expressed by the stimulated U937 cells. The specific monoclonal antibody against TNF-alpha diminished the effects of PMA and IFN-gamma on the growth and differentiation of U937 cells. Thus the endogenous TNF-alpha may involved in the mechanism of the effects of PMA and IFN-gamma on the differentiation of U937 cells. The regulatory action of the endogenous TNF-alpha on U937 cells was not due to its cytotoxic effect.

Cell Transformation, Neoplastic↗
PubMed1994

Heroin lung: report of two cases.

Heroin lung is the most frequent complication of heroin intoxication. In September 1991 and January 1993, two young men aged 19 and 22 years presented with a sudden loss of consciousness and cyanosis after injecting heroin. They were both brought to our emergency department in the night and were immediately intubated and given 100% oxygen. Following intravenous naloxone, they both regained consciousness. The first patient's chest X ray revealed increased bilateral perihilar lung markings and mild patchy alveolar edema while the second patient showed a bat's wing shaped confluent alveolar edema. The blood gases in both cases revealed hypoxemia and hypercapnia. Follow-up chest roentgenograms on the second hospital day in case 1 and the third hospital day in case 2 revealed partial clearing of the lung fields. Fever developed on the second hospital day and they both received two weeks of antibiotics prior to discharge. Case 1 had normal pulmonary function testing, but case 2 developed mild restrictive lung changes. Review of the literature shows that heroin can cause a fulminant but rapidly reversible form of pulmonary edema. The treatment for this noncardiogenic pulmonary edema is adequate ventilation, good pulmonary toilet, and naloxone to reverse the respiratory and central nervous system depression. Diuretics, digitalis and morphine are not recommended in the treatment of heroin lung.

Adult↗
PubMed1994

MR imaging of sports-related muscle injuries.

Magnetic resonance (MR) imaging of the thighs of 26 baseball athletes and one softball athlete were studied to evaluate muscle injuries. We documented the abnormalities present in MR imaging after a muscle injury and evaluated the role of MR imaging in muscle injuries. Fifteen of the athletes showed muscle abnormalities in MR images. These include muscle strains without tear, muscle tear, scar and chronic tendon injury. Having the advantages of high tissue contrast and multiplanar display capability, MR allowed direct visualization of the injured muscles and characterization of traumatic lesions. We conclude that MR could be a good imaging modality for evaluating muscle injuries.

Adult↗
PubMed1993

Proposed healing and consolidation mechanisms of rock salt revealed by ESEM.

The grain boundary healing behavior of crushed rock salt was mainly studied by employing the environmental scanning electron microscope (ESEM) to study the consolidation mechanism of rock salt backfill. Dedicated miniature round rock salt specimens were prepared for observation of the water trapping effect by using a cold stage in the ESEM to reach saturation conditions. Comparable high pressure pellets were prepared for measuring the crystal growth. Consolidation tests using materials made at different pressures and containing different moisture levels were conducted in order to construct the proposed mechanism. Direct observation of specimens in the ESEM resulted in viewing water trapped on the surface and the formation of a water meniscus between two particles. The concentration of brine at the grain boundary was observed as contributing to the amount of recrystallization. From aforementioned observations, a schematic drawing of the dissolution and recrystallization process may be redrawn. The amount of water therefore has a great effect on the consolidation of rock salt and is possibly due to the sliding, rotation, or crushing of the contact zone of the granular material. From such a study, tentative healing and consolidation mechanisms can be deduced.

Microscopy, Electron, Scanning↗
PubMed1993

No detrimental effects in delaying initiation of gonadotropin administration after pituitary desensitization with gonadotropin-releasing hormone agonist.

OBJECTIVE: To determine if delaying initiation of exogenous gonadotropin administration after pituitary desensitization with gonadotropin-releasing hormone agonist (GnRH-a) is a realistic option to avoid scheduling clinical and laboratory work on weekends/holidays. DESIGN, PATIENTS: A review of 57 in vitro fertilization (IVF) cycles in which, after pituitary desensitization with GnRH-a, initiation of gonadotropin administration were delayed in an attempt to avoid off-hour work. Thirty-eight IVF cohort cycles served as control. SETTING: Tertiary medical center. RESULTS: There were no statistically significant differences in ovarian response, dose of gonadotropin required, oocytes and embryos obtained, pregnancy rates, and abortion rates between groups. Eighty-three percent of the delayed cycles had clinical and laboratory work that fell within weekdays. CONCLUSION: Delaying initiation of exogenous gonadotropin administration after pituitary desensitization had no detrimental effects on IVF outcomes. It may be used to avoid scheduling work on weekends/holidays.

Adult↗