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Biomedical subjects

M Wang

Publications and source records attributed to M Wang.

At least 1,009 records · Page 56Linked to original sources
PubMed1988

Analysis of thromboelastogram on coagulation and fibrinolysis.

Hartert's thromboelastography has been used in the diagnosis of abnormal blood clotting for more than 20 years. From a thromboelastogram three parameters are obtained, viz, the reaction time 'r', the rate of formation of fibrin clot 'k', the maximum elasticity of thrombus 'amax'. It is desirable, however, to know the equation that describes the thromboelastogram both in the period in which the complex modulus increases with time because of coagulation, and in the period in which the complex modulus decreases with time because of fibrinolysis. The parameters of the equation could then be used as a diagnostic criterion; yielding information on the mechanism of coagulation and fibrinolysis. Based on our experimental results on human blood in normal and abnormal subjects, we found that the complex modulus of thromboelastograms can be expressed by the sum of two terms, one describing the increase of the complex modulus during coagulation, G1 = G'1 Exp (-tau 1/t), the other describing the decrease of the complex modulus during fibrinolysis, G2 = G'2 Exp (-tau 2/(t-D) when t greater than D. G2 = 0 when t less than D. The compound complex modulus from coagulation to fibrinolysis is G = G1 - G2. Here t is the clotting time, and G'1, G'2, tau 1, tau 2, and D are five constants to be identified. These five constants can be used for diagnostic and prognostic purposes.

Adult↗
PubMed1987

Fractal model of ion-channel kinetics.

Markov models with discrete states, such as closed in equilibrium with closed in equilibrium with open have been widely used to model the kinetics of ion channels in the cell membrane. In these models the transition probabilities per unit time (the kinetic rate constants) are independent of the time scale on which they are measured. However, in many physical systems, a property, L, depends on the scale, epsilon, at which it is measured such that L(epsilon) alpha epsilon 1-D where D is the fractal dimension. Such systems are said to be 'fractal'. Based on the assumption that the kinetic rates are given by k(t) alpha t1-D we derive a fractal model of ion-channel kinetics. This fractal model has fewer adjustable parameters, is more consistent with the dynamics of protein conformations, and fits the single-channel recordings from the corneal endothelium better than the discrete-state Markov model.

Animals↗
PubMed1987

Evidence for intermediate filaments in squirrelfish erythrophores of Holocentrus ascensionus (Rufus).

We have documented the presence of intermediate filaments (IF) in cultured erythrophores of the squirrelfish Holocentrus ascensionus (Rufus). SDS-PAGE and Western blots with monoclonal antibodies T11 and R12 demonstrated that isolated IF consisted of a pair of polypeptides of 54 and 52 kDa. Immunofluorescent studies revealed that the two proteins formed prominent radially oriented IF networks in erythrophores. Immunoelectron microscopic studies showed that the IF were distributed in a "spider-web"-like network of filaments which occasionally intersected with the microtubule surfaces. The IF proteins also were found in fish iridiphores but not in fish epithelial cells which cocultured with the chromatophores.

Animals↗
PubMed1987

Diagnosis of tertian malaria by enzyme-linked immunosorbent assay.

A method of ELISA diagnosis of tertian malaria based on detecting Plasmodium vivax antigen in red blood cells (RBC) was developed, using 0.16 ml of packed, washed, and sonicated RBC. 68 blood samples from tertian malaria cases were examined; 67 (98.5%) were positive. 104 normal persons were all negative by this test. The lowest parasite number detected was 3 parasites/10(5) RBC on a thin film, or 1-2 parasites per thick film of usual size.

Animals↗
PubMed1987

Polarized pigment granule transport occurs in the absence of microtubules in squirrelfish erythrophores: studies of the effects of estramustine.

We have re-examined the involvement of microtubules in the process of pigment granule transport in squirrelfish erythrophores in situ (i.e. on scales). Light-microscopic studies revealed that following exposure to 5 microM-nocodazole for 1 h at 4 degrees C erythrophores retained an ability to aggregate and disperse their pigment uniformly, though at reduced rates. Serial thick-section stereo high-voltage electron-microscopic studies showed that the entire microtubule population was removed by drug treatment and that the microtubules were not reassembled as a result of pigment translocation processes in the presence of reduced levels of nocodazole (0.4 microM). Immunofluorescence microscopic studies confirmed that nocodazole (0.5-1 microM) produced rapid disassembly of the microtubules. Whole-mount electron-microscopic studies showed that the pigment granules were suspended in a cross-linking network of 3-10 nm filaments, which appeared to support ordered pigment transport in situ in the absence of microtubules. Drug inhibition studies showed that micromolar levels of estramustine, a novel anti-MAPs (microtubule-associated proteins) drug, reversibly inhibited pigment transport. The results suggest that an estramustine-sensitive cytomatrix component might produce polarized pigment transport in intact erythrophores.

Animals↗
PubMed1987

[Value of prophylactic irradiation to supraclavicular areas in small cell lung carcinoma--analysis of 104 patients].

A series of 104 patients with limited small cell lung carcinoma was treated by combination of chemotherapy and radiotherapy from August 1975 to July 1981. 104 patients were divided into three groups: prophylactic irradiation to supraclavicular areas (14 patients), non-prophylactic group (72 patients), non-prophylactic irradiation with positive supraclavicular lymph node metastasis after the treatment (18 patients). The 5 year survival rates of the three groups were 14%, 6% and 0%. Distant metastasis rates after the treatment were 36%, 52% and 61%, respectively. The supraclavicular lymph node metastasis rate after the treatment was higher in patients with intra-thoracic lymph node metastasis before the treatment (25%) than in those without this metastasis (0%). It is suggested that, for small cell lung cancer patients, especially with intra-thoracic lymph node metastasis before the treatment, prophylactic irradiation to the supraclavicular areas be valuable.

Adult↗
PubMed1987

[Preliminary evaluation of the combination of Chinese herbal medicine (destagnation) and radiotherapy for esophageal cancer].

From May 1973 to March 1979, a prospective randomized clinical trial on 425 patients with esophageal cancer was conducted. 194 patients were allotted into the destagnation plus radiotherapy group, the other 231 into radiotherapy only group. The result shows that the combination of destagnation and radiotherapy does not give a result superior to radiotherapy alone. However, destagnation does not increase either hematogenous, lymphatic metastasis, perforation or hemorrhea of the esophageal cancer.

Clinical Trials as Topic↗
PubMed1986

Interactions between adenosine and oscillatory cAMP signaling regulate size and pattern in Dictyostelium.

We present evidence for the hypothesis that in multicellular structures of Dictyostelium, production of adenosine by hydrolysis of cAMP near the tip region prevents both generation of competing tips and differentiation of prespore cells near the tip, and thus establishes a "prestalk" region. We demonstrate that adenosine affects the immunological prespore specific staining pattern in slugs in a manner opposite to cAMP:cAMP induces an increase of prespore antigen; adenosine induces a decrease. When endogenous adenosine is removed from slugs, prespore vacuoles are synthesized throughout the prestalk region. Adenosine was found to inhibit the induction of prespore differentiation by cAMP in an apparently competitive manner. It was also found that adenosine specifically increased the amount of tissue controlled by one tip, probably by inhibiting generation of competing oscillators. Removing endogenous adenosine from slugs resulted in a decrease of tip dominance.

Adenosine↗
PubMed1986

Activities of cerebral dihydropteridine reductase and tyrosine hydroxylase in chronic uremia in rats.

The effect of chronic uremia on activities of cerebral dihydropteridine reductase (DHPR) and tyrosine hydroxylase (TH) and content of norepinephrine and dopamine was investigated in the male Sprague-Dawley rats. The uremic animals were fed diets containing either 8% or 18% casein ad libitum, and sham-operated pair-fed and ad libitum fed animals were used as controls. There were no significant differences in TH activity between the groups fed the two levels of protein. Uremic rats had lower activity of TH than pair-fed controls, and pair-fed controls had lower activity than ad libitum-fed animals. DHPR activity and norepinephrine and dopamine content did not differ among the groups. Our study suggests that the chronic uremic condition or restricted feeding causes a decrease in brain TH activity which is not mediated by decreased DHPR activity. Further, this decreased enzyme activity does not result in depressed catecholamine content, indicating the presence of a highly regulated mechanism controlling catecholamine levels.

Animals↗
PubMed1986

Occult gastric cancer manifested by progressive shortness of breath in a young adult.

We have reported a case of occult, diffuse gastric cancer in a young adult with progressive shortness of breath and bilateral pulmonary interstitial infiltrates. Progressive shortness of breath may be the first or only manifestation of occult gastric cancer caused by either lymphangitic carcinomatosis or microscopic tumor emboli to the lungs. Widespread recognition of this syndrome, a high index of suspicion, and prompt lung biopsy are necessary to make the correct diagnosis. With progress in chemotherapy for malignant diseases, early diagnosis and specific treatment may improve the prognosis of this condition.

Adenocarcinoma, Mucinous↗
PubMed1986

Phorbol 12,13-dibutyrate increases tyrosine hydroxylase activity in the superior cervical ganglion of the rat.

Phorbol 12,13-dibutyrate (PDBu) increased the production of 3,4-dihydroxyphenylalanine (DOPA) in the superior cervical ganglion of the rat. This effect occurred without a detectable lag and persisted for at least 90 min of incubation. The action of PDBu was half-maximal at a concentration of approximately 0.1 microM; at high concentrations, PDBu produced about a twofold increase in DOPA accumulation. PDBu increased DOPA production in decentralized ganglia and in ganglia incubated in a Ca2+-free medium. The action of PDBu was additive with the actions of dimethylphenylpiperazinium, muscarine, and 8-Br-cyclic AMP, all of which also increase DOPA accumulation, and was not inhibited by the cholinergic antagonists hexamethonium (3 mM) and atropine (6 microM). Finally, PDBu did not increase the content of cyclic AMP in the ganglion. Thus, the action of PDBu does not appear to be mediated by the release of neurotransmitters from preganglionic nerve terminals, by the stimulation of cholinergic receptors in the ganglion, or by an increase in ganglionic cyclic AMP. PDBu also increased the incorporation of 32Pi into tyrosine hydroxylase. PDBu activates protein kinase C, which in turn may phosphorylate tyrosine hydroxylase and increase the rate of DOPA synthesis in the ganglion.

8-Bromo Cyclic Adenosine Monophosphate↗
PubMed1986

Changes in psychophysiological and conditioning variables during chlormethiazole-medicated and unmedicated ethanol withdrawal: preliminary report.

Autonomic lability during ethanol withdrawal in chlormethiazole-medicated and unmedicated groups was investigated using electrodermal measures. Vulnerability to Pavlovian aversive conditioning was also assessed. Ethanol withdrawal was associated with increased autonomic arousal and aversive conditioning, suggesting an increased risk of phobia acquisition. Chlormethiazole administered during ethanol withdrawal may protect against such developments.

Adolescent↗