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Biomedical subjects

M L Wang

Publications and source records attributed to M L Wang.

At least 91 records · Page 5Linked to original sources
PubMed1989

Extensive heterogeneity in the hemagglutinin of egg-grown influenza viruses from different patients.

We establish that the cultivation of influenza (H3N2) virus from any infected individual in chicken embryos (eggs) can result in the isolation of viruses with antigenic and/or structural heterogeneity in the hemagglutinin (HA) molecule. This variability contrasted sharply with the apparent lack of antigenic alterations in the HA of influenza viruses isolated from patients in Madin Darby canine kidney (MDCK) cells. The most common subpopulation of egg-grown influenza viruses had the same phenotype as MDCK cell-grown virus and may best represent the virus circulating in humans. It should be considered the optimal strain for use in vaccine and epidemiologic studies.

Amino Acid Sequence↗
PubMed1989

Rhythms of serum melatonin in patients with spinal lesions at the cervical, thoracic or lumbar region.

The neural pathway essential for the diurnal rhythm of serum melatonin was studied in humans. Blood samples from 17 patients with chronic lesions of cervical (n = 8), low thoracic or lumbar (n = 9) spinal cord were collected at 0200, 0400, 1000 and 1400 h of their normal light-dark cycle. Blood samples were also collected from eight control subjects at 0200 and 1400 h. No special treatment of food, drug or photoperiod was implemented. Serum melatonin was extracted by dichloromethane and determined by radioimmunoassay. In patients with cervical spinal lesions (C3-C7), it was found that serum melatonin levels were low and no diurnal rhythm was observed. Conversely, diurnal rhythm of circulating melatonin with significantly higher levels (P less than 0.01) in the dark period were observed in individuals with injuries at the low thoracic or lumbar regions (T9-L2). In the second experiment, blood samples from two other patients were collected for three consecutive days during acute period of spinal injuries (cervical or upper thoracic region) and serum melatonin concentrations were determined. Again, there were low levels of serum melatonin with no observable diurnal rhythm in the patient with cervical lesion (C4-5). However, diurnal rhythms were maintained with high levels in the dark period in the patient with upper thoracic spinal (T2-3) transection. Our data suggest that the cervical region of the spinal cord is part of the neural pathway essential for the diurnal rhythm of pineal melatonin secretion in human beings.

Adult↗
PubMed1989

In vitro fertilization, gamete intrafallopian transfer and combined IVF-GIFT results: three-year experience at Chang Gung Memorial Hospital.

A review is presented summarizing the IVF-ET, GIFT and combined IVF-ET-GIFT experienced at Chang Gung Memorial Hospital. Since the building of an aseptic dust free laboratory next to the operation room, the clinical pregnancy rate has been 12.2% per embryo transfer in IVF-ET, 16.7% in the GIFT program and 30.0% in the combined IVF-GIFT program. The overall clinical pregnancy rate was 14.9%. The overall pregnancy rate appeared to be independent of the causes of infertility, be it tubal factor, endometriosis or unexplained infertility. It was lower in couples with male factor or combined factors. The different regimens for follicular stimulation were hMG-hCG, clomiphene-hMG-hCG and FSH-hMG-hCG. No one regimen showed a better pregnancy rate than the others. The methods of oocyte retrieval were laparascopy, laparotomy, transbladder ultrasound-guided, and transvaginal ultrasound-guided retrieval. There were 4.53 oocytes retrieved pertreatment cycle. The transvaginal ultrasoundguided oocyte retrieval has greatly simplified the procedures in the IVF-ET program. The patient selection was important not only for the indications but also for the methods of IVF-ET, GIET and combined IVF-GIFT.

Evaluation Studies as Topic↗
PubMed1988

Chemodectoma of the temporal bone: a comparison of surgical and radiotherapeutic results.

Between January 1950 and December 1981, 32 patients with chemodectomas of the temporal bone were treated at the University of Iowa Hospitals and Clinics. Thirteen patients were treated with surgery alone, 15 with radiation therapy alone, one with preoperative radiation therapy and surgery, and three with surgery and postoperative radiation therapy. In general, the patients treated with radiotherapy alone or combined therapy (radiotherapy group) had more advanced tumors than those treated with surgery alone (surgery group). For the surgery group, the initial local control rate was 46% and the ultimate local control rate 84% following salvage with additional surgery, 31% developed complications, and 78% survived 10 years. For the radiotherapy group, 84% had local tumor control, 11% developed complications, and 77% survived 10 years. These results demonstrate that radiation therapy is an effective treatment modality for chemodectomas of the temporal bone.

Adult↗
PubMed1987

Inoperable adenocarcinoma of endometrium: radiation therapy.

Between 1960 and 1979, 41 patients with adenocarcinoma of the endometrium who were poor surgical risks were treated with radiation therapy at the University of Iowa. Local tumor control was achieved in 78% of the patients, 5% manifested complications, and 46% survived 5 years ("uncorrected" 5-year survival rate). Intercurrent disease was the major cause of death (54%), and intrauterine recurrence (22%) was the most frequent recurrence. Intraperitoneal spread (12%) occurred as commonly as hematogenous metastases (12%). Three of nine local failures occurred after 5 years. Local control rates correlated well with clinical stage, and the survival rates correlated well with the stage and grade of the tumor. Local tumor control was achieved in 95% of patients who received greater than 7,000 mg-h intracavitary radium, compared with 63% of patients treated with less than 7,000 mg-h.

Adenocarcinoma↗
PubMed1986

Production of IgA monoclonal antibodies against influenza A virus.

Nineteen IgA monoclonal antibodies against influenza A virus X-31 were obtained following intranasal infection of mice with influenza A virus X-31. It was demonstrated that specificities of IgA monoclonal antibodies are similar to those of IgG monoclonal antibodies. These IgA antibodies might be useful for the study of mucosal immunity against influenza A viruses. Infection may be an easier and better way of producing monoclonal antibodies against some viral agents.

Animals↗
PubMed1986

Comparative analyses of the specificities of anti-influenza hemagglutinin antibodies in human sera.

Estimates of the variety of specificities of anti-influenza hemagglutinin antibodies in postinfection human sera taken between 1969 and 1971 and in 1978 were made by using Fab fragments of defined monoclonal antibodies in competitive virus-binding assays. The results obtained with the sera taken between 1969 and 1971 indicated that different sera contained antibodies with different ranges of specificities, whereas the 1978 sera mainly contained a broad range of antibodies. The results are discussed in relation to the mechanism of antigenic drift in influenza virus, the commonly observed antigenic heterogeneity of influenza virus isolates, and the efficacy of antiinfluenza vaccination.

Antibodies, Viral↗
PubMed1986

The use of micropeptide maps and monoclonal antibodies for antigenic variation analysis of influenza A viruses isolated in China from 1972 to 1983.

125I-labelled haemagglutinin (HA) micropeptide mapping and haemagglutinin inhibition (HAI) tests with monoclonal antibodies were used in analysing antigenic variation of six strains of influenza A virus isolated from 1972 to 1983 in China. The results from micropeptide mapping generally coincided with those of sequence analysis. 125I-labelled HA micropeptide mapping is a simple, reproducible and practical method for surveillance of influenza, especially in combination with HAI test using monoclonal antibodies.

Amino Acid Sequence↗
PubMed1985

Fusion mutants of the influenza virus hemagglutinin glycoprotein.

The influenza virus hemagglutinin (HA) mediates viral entry into cells by a low pH induced membrane-fusion event in endosomal vesicles. Mutant viruses with altered pH dependence for both hemolysis and the HA conformational change required for fusion were selected for their ability to grow in cells treated with amantadine hydrochloride, which raises the endosomal pH. The amino acid sequence and three-dimensional location of 19 substitutions on the HA are reported. The mutations fall into two groups, one that results in the destabilization of the pH 7.0 location of the hydrophobic N-terminal HA2 peptide, and a second that results in the alteration of intersubunit contacts, suggesting a large distortion or disruption of these contacts in the "fusion-active" conformation.

Amantadine↗
PubMed1985

Lung function studies of asbestos workers.

Pulmonary function tests have been conducted on 155 asbestos workers and 130 referents. It was found that the lung function impairment in asbestos workers is predominantly a restrictive ventilatory defect appearing even when radiographic changes are not detectable. There was, however, no evidence of airway obstruction. As the disease progressed, all the pulmonary function indices, including vital capacity (VC), forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1.0), maximal ventilation volume (MVV), total lung capacity (TLC), and pulmonary diffusing capacity (DLCO), were reduced dramatically, with the exception of FEV1.0/FVC(%). It is suggested that both radiographic examination and pulmonary function tests should be used as early detection measures of asbestos-induced lung disorders. VC, FVC, and FEV1.0 are the simplest, most reproducible, and most valid indices for the health surveillance of asbestos workers, while the FVC test is the most valuable for epidemiologic study. With stepwise regression analysis a quantitative relationship between dust exposure and pulmonary function was demonstrated. There was no significant difference in the small airway function of the exposed workers and the referents. Further study is needed to investigate the possibility of asbestos-induced small airway obstruction and to estimate the roles played by cigarette smoking and air pollution.

Adult↗
PubMed1984

Studies on the adaptation of influenza viruses to MDCK cells.

The amino acid sequences and biological properties of the haemagglutinin of three variants of the influenza virus X-31 (H3N2) selected for their capacity to grow in MDCK cells are reported. In two variants, amino acid substitutions at HA1 residues 8 and 144 correlated with the loss of a site for glycosylation and specific changes in antigenicity, respectively. In all three variants substitution of an arginine residue for histidine at HA1 position 17 was correlated with increased pH optima of haemolysis. The importance of this substitution for cleavage of the haemagglutinin precursor required to produce infectious virus is discussed in relation to the three-dimensional structure of X-31 haemagglutinin.

Adaptation, Physiological↗
PubMed1984

Habituation of human limbic neuronal response to sensory stimulation.

Hippocampal, parahippocampal gyrus, and amygdalar neuronal responses to visual and acoustic stimuli were analyzed during trains of several hundred stimulus repetitions as part of an investigation of sensory pathways to medial temporal lobe structures in complex-partial epilepsy patients who were being monitored with depth electrodes. Ten percent of more than 500 single and multiple units tested were responsive to simple sensory stimuli. The majority of the responsive units were recorded in the posterior parahippocampal gyrus (HG) during visual stimulation. Although neurons in pes hippocampi (PH; Ammons's horn) were also responsive to photic stimuli, no visually responsive units were found in amygdala. Very few units were responsive to acoustic stimuli, and these were found only in PH and amygdala, and not in HG. Significant trends of increase or decrease in response amplitude during trains of stimuli were found in all acoustically responsive units. Significant trends of visual response amplitude increase or decrease were found in 20% of PH units, and in 44% of HG units. Mean latencies of acoustically responsive units were longer than those of visually responsive units, and latencies of PH sensory units showing decremental response were longer than nondecremental PH units. Rate of response decrement was usually linear for acoustic responses and exponential for visual responses. The response dynamics of medial temporal lobe neurons are compared with those described in the animal limbic system and are related to habituation of human sensory evoked scalp potentials.

Acoustic Stimulation↗
PubMed1983

Polymerization of vector DNA after transfection into hamster fibroblast cells.

We have transformed hamsters lung fibroblasts with two cloned, selectable markers, the widely used pSV2gpt vector and pNEO3, which confers resistance to neomycin. Analysis of DNA extracted from both individual and pooled groups of several hundred transformants reveal that in these carrier DNA-free transformation experiments, the vector DNA are found in concatenate forms in the transformants. The copy number of the integrated vectors can vary from a few to several hundred. In addition, the efficiency of transformation is ten times higher in the case of pSV2gpt.

Animals↗