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Biomedical subjects

M T Wu

Publications and source records attributed to M T Wu.

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

Outbreak of bronchiolitis obliterans associated with consumption of Sauropus androgynus in Taiwan.

BACKGROUND: In August, 1995, there was an outbreak in Taiwan of rapidly progressive respiratory distress associated with consumption of uncooked Sauropus androgynus, a vegetable with a claimed yet unconfirmed effect on weight control. We report on 23 patients with strikingly similar clinical presentations. METHODS: A structured questionnaire for clinical manifestations was completed. Radiographic findings, pulmonary physiological changes, immunological and microbiological studies, and pathological examination were evaluated. FINDINGS: All patients were young and middle-aged women (mean age 39 years [range 21-52]). They took uncooked S androgynus juice, generally mixed with guava or pineapple juice, for a mean duration of 10 weeks. Progressive dyspnoea and persistent cough were the main symptoms on presentation. Pulmonary function testing uniformly revealed moderate to severe airflow obstruction with mean forced expiratory volume in 1 s (FEV1) of 0.66 L (26% of predicted). No bronchodilator response was observed. Room-air arterial blood gas analysis showed hypoxaemia (mean PaO2 9.6 [SD 1.6] kPa). Chest radiographs were essentially normal. High-resolution computed tomography showed bilateral bronchiectasis and patchy low attenuation of lung parenchyma with mosaic perfusion. Ventilation-perfusion scintigraphic findings were compatible with obstructive lung disease. Histopathology of open lung biopsy specimens in four patients confirmed the presence of bronchiolitis obliterans. Immunohistochemical stains of the open lung biopsy specimens showed predominance of T cells over B cells. Immunofluorescent stains for IgG, IgM, IgA, C1q, C3, and C4 were negative. Serum concentrations of tumour necrosis factor alpha were higher than those of normal controls. Clinical response to prednisolone was limited. INTERPRETATION: We describe an unusual association between bronchiolitis obliterans and ingestion of the vegetable S androgynus. T-cell mediated immunity may be involved in the pathogenesis.

Adult↗
PubMed1996

Azygos blood flow in cirrhosis: measurement with MR imaging and correlation with variceal hemorrhage.

PURPOSE: To evaluate magnetic resonance (MR) measurement of azygos blood flow (ABF) in assessment of risk of variceal hemorrhage in cirrhosis. MATERIALS AND METHODS: ABF in 50 patients with cirrhosis and 20 healthy control subjects was evaluated with phase-contrast cine MR imaging at the transaxial subcarinal plane. Group 1 included nine patients with cervical-drainage varices draining into brachiocephalic vein; group 2 included 41 patients with varices draining into azygos vein and was subdivided as group 2A, 15 patients with variceal hemorrhage, and group 2B, 26 without variceal hemorrhage. RESULTS: Azygos flow rate and velocity were increased in patients compared with that in control subjects. ABF in group 2A was faster than that in group 2B (cutoff, 15 cm/sec; sensitivity, 80%; specificity, 89%). Group 1 had ABF close to that of group 2B, but variceal hemorrhage occurred in seven of nine patients in group 1 versus 15 of 41 patients in group 2 (78% vs 37%; P = .029). CONCLUSION: Patients with cirrhosis with cervical-drainage varices or ABF greater than 15 cm/sec may have higher risk for variceal hemorrhage.

Azygos Vein↗
PubMed1995

Characterization of the interaction of diacylpiperazine antagonists with the human neurokinin-1 receptor: identification of a common binding site for structurally dissimilar antagonists.

We recently described a novel series of diacylpiperazine antagonists of the human neurokinin (NK)-1 receptor. The diacylpiperazine compounds are structurally dissimilar from previously described NK-1 antagonists. L-161,664 [1-(N,N-diphenylaminocarbonyl)-4-(N',N'-di-n-pentylaminocarbony l) piperazine-2-diethylaminopropylcarboxamide] inhibits 125I-substance P binding to the human NK-1 receptor with an IC50 of 43 +/- 21 nM but has 50-fold and 200-fold lower affinity for the human NK-2 and NK-3 receptors, respectively. L-161,664 inhibits substance P-stimulated inositol monophosphate accumulation in Chinese hamster ovary cells expressing the human NK-1 receptor by increasing the EC50 for substance P but not its maximal effect. The compound decreases the apparent affinity of the NK-1 receptor for 125I-substance P and does not alter the rate of dissociation of 125I-substance P from the receptor. These data indicate that L-161,664 is a potent and selective competitive antagonist of the human NK-1 receptor. L-161,664 has reduced affinity for mutants of the NK-1 receptor in which alanine has replaced Gln-165 in transmembrane helix 4, His-197 in helix 5, His-265 in helix 6, or Tyr-287 in helix 7. Similarly, a novel series of acyclic 2-benzhydryl-2-aminoethyl ethers that we have recently shown to be competitive NK-1 receptor antagonists have reduced affinity for the Q165A. H197A, and H265A mutant receptors. These residues have been shown to be important for binding of quinuclidine, tryptophan benzyl ester, and perhydroisoindole antagonists to the receptor. Analysis of the interaction of structural analogs of L-161,664 with the Q165A mutant receptor suggests that this residue interacts with the 2-diethylaminopropylcarboxamide side chain of L-161,664. Thus, even though the diacylpiperazine antagonists are structurally dissimilar from other classes of antagonists described to date, these data suggest that a common antagonist binding site that accomodates much structural diversity is present in the human NK-1 receptor. Furthermore, these data, combined with those obtained from medicinal chemistry approaches, suggest a minimum pharmacophore map for the interaction of these diverse ligands with the NK-1 binding site.

Amino Acid Sequence↗
PubMed1994

Use of quantitative CT to predict postoperative lung function in patients with lung cancer.

PURPOSE: To evaluate the effectiveness of quantitative computed tomography (CT) for predicting postoperative lung function in patients with lung cancer. MATERIALS AND METHODS: Preoperative spirometry and conventional CT of the chest were performed in 38 patients. A postprocessing CT program was applied to quantitate the volume of whole-lung parenchyma with attenuations of -500 to -910 HU; this was defined as total functional lung volume (TFLV). The regional functional lung volume (RFLV) of the lobes or lung to be resected was quantitated separately. CT-predicted postoperative forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC) were derived by multiplying the preoperative spirometry values by (1 - RFLV/TFLV). RESULTS: CT-predicted values correlated well with postoperatively measured results (FEV1: r = .93, P < .001; FVC: r = .86, P < .001) in patients who underwent pneumonectomy or lobectomy, regardless of the patient's preoperative ventilation status. CONCLUSION: This method is effective in the prediction of postoperative FEV1 and FVC in patients undergoing pulmonary resection.

Aged↗
PubMed1990

[The analysis of motivation and attitude of premarital medical examinees].

The study aims to analyse the motivation and attitude of premarital medical examinees. Ninety-two premarital medical examines, which include 46 self-paid persons and 46 government paid (subsidized by the Department of Health) visited the Family Clinic. They were studied from Oct. 27, 1988 to Nov. 8, 1989. Among 48 male and 44 female examinees, the sex ratio (male:female) was 1.09:1. The predominant age distribution was 26-30 y/o (58.2%); and the predominant level of education was college (54.4%). Questionnaires were sent to these premarital medical examinees. We received 70 questionnaires-47.1% from self-paid, and 52.9% from government paid. The recovery rate was 76.1%. The results of analysis were: 1) Concerning the motivation of examination, 35.1% of self-paid were introduced by relatives or friends; while 50% of government paid were introduced by newspapers; 41.2% of the total response were afraid of genetic disease. 2) Concerning the opinion of the examination fee, there were no significant differences between those of self-paid and government paid.

Adolescent↗
PubMed1989

[A case report of carotenemia].

Carotenemia is a common disease in children, and it is mainly due to excessive intake of food enriched with carotene. A fourteen-year-old girl, whose skin had been discolored yellow for several months, was brought to Kaohsiung Medical College Hospital for examination. Physical examination revealed she had a marked yellow color skin, especially on the palms and soles; conjunctiva was not anemic; sclera was not icteric; breath and heart sounds were normal; liver and spleen were not enlarged. Laboratory examination revealed normal results for the liver function test, however, serum carotene was elevated to 460 micrograms/dl in contrast to 80 micrograms/dl from a same-aged healthy child as a control (normal range of the serum carotene: 50-250 micrograms/dl). Tracing back her past history, she had taken a lot of oranges daily for more than one year. After consulting a nutritionist and changing her eating habits to a balanced diet for eight weeks, the serum carotene level decreased to 270 micrograms/dl (same-aged healthy child: 30 micrograms/dl). The skin color was also improved.

Adolescent↗
PubMed1988

A study on the induction of differentiation of human leukemic cells by harringtonine combined with cytarabine.

Both harringtonine (Harr) and Ara-C are effective for treatment of ANLL. Since it was suggested that Harr could induce leukemic cells to differentiate and Ara-C might be a weak inducer of leukemic cell differentiation, we investigated the effect of Harr in combination with Ara-C on inducing differentiation of leukemic cells. Ten patients with ANLL were treated with low dose Harr in combination with low dose Ara-C. Complete remission was achieved in 8 of the 10 patients. After therapy, severe pancytopenia and moderate myelosuppression occurred in two patients who achieved remission. Four patients demonstrated a decrease in blast cells with an associated transient increase in mature granulocytes during therapy. Auer bodies appeared in 7-8% mature granulocytes in peripheral blood and in bone marrow on the 14th day of combination therapy in one patient. Freshly isolated leukemic cells from six pretreatment patients were cultured in liquid in the presence of Harr in combination with Ara-C. Apparent evidence of differentiation of leukemic cells and Auer bodies in the cytoplasm of mature granulocytic cells were observed in two of the six patients. The above results seem to suggest that the therapeutic effect of low dose Harr plus low dose Ara-C may result from both differentiation induction and cytotoxicity of the leukemic cells.

Adolescent↗
PubMed1986

Kinetic studies and structure-activity relationships of bispyridinium oximes as reactivators of acetylcholinesterase inhibited by organophosphorus compounds.

The kinetics of the reactivation of acetylcholinesterase inhibited by isopropyl methylphosphonofluoridate was studied. The reactivators used include nine bispyridinium monooximes and three bispyridinium dioximes. The dissociation constant (Kd) and the rate constant (k2) of dephosphorylation of the complex formed from the organophosphorus acetylcholinesterase (OP-AChE) and the oxime were measured. The reactivation parameters obtained from the in vitro kinetic studies were used to elucidate the structure-activity relationships. The hydrophobic property of a nonoxime substituent at the 3-position on the pyridinium ring can exert a positive effect on their binding affinity to OP-AChE. However, the rate constants (k2) of the nucleophilic displacement of OP-AChE by oximes depend negatively on these physical and structural factors of the oximes. The correlations of the in vivo antidotal efficacy (ED50) of these bispyridinium oximes have been analyzed with their pharmacological properties, e.g., reactivation potency, antimuscarinic activities, and antinicotinic activities. However, no satisfactory correlations were observed. It may be concluded that the detoxication mechanism of poisoning by isopropyl methylphosphonofluoridate is different from those of pinacolyl methylphosphonofluoridate and paraoxon.

Acetylcholinesterase↗
PubMed1984

Heat stress responses in cultured plant cells : effect of culture handling and age.

The pipetting of pear (Pyrus communis cv Bartlett) suspension cultures was followed by a substantial but transient decrease in heat sensitivity. During a culture cycle, pear cells were most sensitive to heat at day 3, which coincided with the period of most active cell division. To minimize serious artifacts, the influence of culture handling and age on parameters such as heat sensitivity must be standardized.

Journal Article↗
PubMed1984

Heat Stress Responses in Cultured Plant Cells : Heat Tolerance Induced by Heat Shock versus Elevated Growing Temperature.

Using cultured pear (Pyrus communis cv Bartlett) cells, heat tolerance induced by heat shock was compared to that developed during growth at high temperature. After growth at 22 degrees C, cells exposed to 38 degrees C for 20 minutes (heat shock) showed maximum increased tolerance within 6 hours. Cells grown at 30 degrees C developed maximum heat tolerance after 5 to 6 days; this maximum was well below that induced by heat shock. Heat shock-induced tolerance was fully retained at 22 degrees C for 2 days and was only partly lost after 4 days. However, pear cells acclimated at 30 degrees C lost all acquired heat tolerance 1 to 2 days after transfer to 22 degrees C. In addition, cells which had been heat-acclimated by growth at 30 degrees C showed an additional increase in heat tolerance in response to 39 degrees C heat shock. The most striking difference between heat shock and high growth temperature effects on heat tolerance was revealed when tolerance was determined using viability tests based on different cell functions. Growth at 30 degrees C produced a general hardening, i.e. increased heat tolerance was observed with all three viability tests. In contrast, significantly increased tolerance of heat-shocked cells was observed only with the culture regrowth test. The two types of treatment evoke different mechanisms of heat acclimation.

Journal Article↗
PubMed1984

Adverse behavioral effects of the anticholinesterase poisoning protector pralidoxime methanesulfonate.

Pralidoxime methanesulfonate (P2S) has anticholinesterase protective properties, but it also has an array of gastrointestinal (GI) symptoms. Because such a symptom would be disadvantageous to occupational workers who handled and used organophosphorus anticholinesterase continuously, and to soldiers who have had oral pretreatment in a situation where anticholinesterase agent poisoning is a possibility, this question was investigated in rats using three behavioral paradigms to evaluate the feasibility of the oral prophylactic regimen. These are: (1) conditioned taste aversion (CTA), (2) operant behavior and (3) spontaneous locomotor activity (SMA); these three behavioral parameters are analogous to toxicant-induced gastrointestinal (GI) disturbances, performance of learned tasks and behavioral arousal, respectively. Dose-response studies of P2S in dose levels of 0.2, 0.4, 0.8 and 1.6 gm/kg (P.O.) were evaluated. The results consistently demonstrated that only the highest dose significantly produced marked decreases in consumption of flavored solution associated with its ingestion, suppressed keypress response maintained under a 20-response fixed-ratio schedule of water presentation, and inhibited SMA. By inference, if CTA, operant behavior and SMA are appropriate paradigms, P2S, on an acute single oral high dose level, would cause GI disturbances, impair task performance and induce sedation in man.

Animals↗
PubMed1983

Heat stress responses in cultured plant cells : development and comparison of viability tests.

The response of suspension-cultured pear (Pyrus communis cv Bartlett) cells to heat stress was studied using three viability tests: regrowth (culture growth during 10 days after stress); triphenyltetrazolium chloride reduction; and electrolyte leakage. Critical (50% injury) temperatures for a 20-minute exposure were 42 degrees , 52 degrees , and 56 degrees C, respectively, for these viability tests. Electrolyte leakage had the lowest temperature coefficient. Heat stress inhibition of triphenyltetrazolium chloride reducing capacity was much greater if the viability test was conducted 3 days, rather than immediately, after the stress treatment. Consistent with a major role for indirect metabolic strain in heat injury, treatment with 3.6 micromolar cycloheximide and heat stress (20 minutes at 43 degrees C) affected culture regrowth similarly. We conclude that the measurements of direct response are not adequate substitutes for regrowth tests in assessing heat injury to cultured plant cells.

Journal Article↗
PubMed1980

A new class of angiotensin-converting enzyme inhibitors.

Much current attention focuses on the renin-angiotensin system in relation to mechanisms controlling blood pressure and renal function. Recent demonstrations (ref. 1, ref. 2 and refs therein) that angiotensin-converting enzyme inhibitors show promising clinical antihypertensive properties have been of particular interest. We now report on the design of a novel series of substituted N-carboxymethyl-dipeptides which are active in inhibiting angiotensin-converting enzyme at nanomolar levels. We suggest that these compounds are transition-state inhibitors and that extensions of this design to other metalloendopeptidases merit further study.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1978

Toxicity of Phytophthora infestans and Alternaria solani to chick embryos.

None of the extracts and culture filtrates from growth of 9 races of Phytophthora infestans on living potato tissue and potato dextrose broth are toxic to chick embryos. Chloroform extracts of 4 out of 10 isolates of Alternaria solani grown on potato dextrose broth showed some toxicity to chick embryos.

Alternaria↗
PubMed1978

Teratogenic potential of blighted potato concentrate in rabbits, hamsters, and miniature swine.

Freeze-dried preparations of potatoes infected with phytophthora infestans or Alternaria solani were fed to pregnant hamsters, rabbits, and miniature swine. No evidence was observed that these diets or the extracts of respective blights were capable of producing teratologic effects in hamsters. Lesions of neurulation and anencephaly were noticed in rabbits and swine, respectively. The need for further pharmacological and toxicological evaluation in sensitive species is emphasized.

Alternaria↗