Biomedical subjects
Publications and source records attributed to Y C Wu.
Bioactivity-guided fractionation of a CHCl3 extract of the soft coral Lobophytum michaelae afforded a new cytotoxic cembranolide, lobomichaolide (1), and a known cytotoxic cembranolide, crassolide (2). The structure of 1 was determined by spectral and X-ray crystallographic analysis.
The epidemiology of penicillin-susceptible Neisseria gonorrhoeae isolated in Taiwan from 1960 to 1990 is summarized. The isolation of N. gonorrhoeae less sensitive to penicillin (i.e., with intrinsic resistance) was first reported in 1960. The rate at which organisms less sensitive to penicillin (MIC, greater than or equal to 0.5 microgram/mL) were isolated increased to 17%, 50%, 80.1%, and 88.8% in 1967, 1975, 1984, and 1990, respectively. Penicillinase-producing N. gonorrhoeae (PPNG) first appeared in Taiwan in late 1976, and the first six strains of PPNG isolated were from United States military servicemen who had relocated from Southeast Asia. The percentage of PPNG strains rose to 37.82% in 1982, and has remained high (50%-62%) since 1983. In the present study, resistance of N. gonorrhoeae to spectinomycin (MIC, greater than 32 micrograms/mL), third-generation cephalosporins (MIC, greater than 4 micrograms/mL), or quinolones (MIC, greater than 4 micrograms/mL) has not been found. Strains requiring arginine, hypoxanthine, and uracil for growth, which frequently cause disseminated gonococcal infections, were not isolated. PPNG strains tended to be of the prototrophic auxotype (55%); non-PPNG strains were mostly of the proline-requiring auxotype (48.8%). Two kinds of R plasmids were isolated in the PPNG strains: the 4.4-MD Asian type (82%-95%) and the 3.05-MD Toronto type (5%-18%). All of the PPNG strains possessing Toronto R plasmid were of the same auxotype/serotype (prototrophic/IB). Evidence suggests that the Asian-type R plasmid was imported into Taiwan in 1976, while the Toronto-type R plasmid may have first emerged in Taiwan in 1983.(ABSTRACT TRUNCATED AT 250 WORDS)
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The pharmacological properties and mechanism of the action of protopine on isolated rat thoracic aorta were examined. It inhibited norepinephrine (NE, 3 microM)-induced tonic contraction in rat thoracic aorta in a concentration-dependent manner (25-100 micrograms/ml). The phasic contraction caused by NE was inhibited only by a high concentration of protopine (100 micrograms/ml). At the plateau of NE-induced tonic contraction, the addition of protopine also caused relaxation. This relaxing effect of protopine was not antagonized by indomethacin (20 microM) or methylene blue (50 microM), and it still existed in denuded rat aorta or in the presence of nifedipine (2-100 microM). Protopine also inhibited high potassium (60 mM)-induced, calcium-dependent (0.03-3 mM) contraction of rat aorta in a concentration-dependent manner. Neither cAMP nor cGMP level was changed by protopine. Both the formation of inositol monophosphate caused by NE and the phasic contraction induced by caffeine were also not affected by protopine. 45Ca2+ influx caused by either NE or K+ was inhibited by protopine concentration-dependently. It is concluded that protopine relaxed the rat thoracic aorta mainly by suppressing the Ca2+ influx through both voltage- and receptor-operated calcium channels.
In Taiwan, the epidemiological status of HCV infection is similar to those observed in other areas of the world, with 1.0% prevalence among adult volunteer blood donors and high prevalences among the high risk groups, by the detection of anti-HCV with synthetic peptide antigens. However, unusually high prevalences, 35.1%, 15.8% and 14.2%, were observed among adult populations in three of the five aboriginal communities. No difference in sex specificity was noted. In 37 (75.0%) of the 48 anti-HCV-positive cases, HCV-RNA was detected by reverse transcription polymerase chain reaction (RT-PCR) assay. None of such particular risk factors as tattooing, sexual promiscuity, operation, blood transfusion, nor intravenous drug abuse could be accounted for this high prevalence of HCV infection. No helpful supporting evidence for ethnic specificity was noted, either. Although a possible sexual transmission between spouses was observed, it is unlikely to be the main cause of the high prevalence in these aboriginal communities. We conclude that the unusually high prevalence of HCV infection observed in some aboriginal communities in Taiwan could be ascribed to poor anti-septic medical practice derived from insufficiency of medical personnel and facilities in these communities as compared with the other regions in Taiwan at the time before twenty years ago.
Percutaneous transvenous mitral commissurotomy (PTMC) was performed in 219 patients with symptomatic, severe rheumatic mitral stenosis. There were 59 men and 160 women, aged 19 to 76 years (mean 43). Pliable, noncalcified valves were present in 139 (group 1), and calcified valves or severe mitral subvalvular lesions, or both, in 80 patients (group 2). Atrial fibrillation was present in 133 patients (61%) and 1+ or 2+ mitral regurgitation in 59 (27%). Technical failure occurred with 3 patients in our early experience. There was no cardiac tamponade or emergency surgery. The only in-hospital death occurred 3 days after the procedure in a group 2 premoribund patient in whom last-resort PTMC created 3+ mitral regurgitation. Mitral regurgitation appeared or increased in 72 patients (33%); 3+ mitral regurgitation resulted in 12 patients (6%). There were 3 systemic embolisms. Atrial left-to-right shunts measured by oximetry developed in 33 patients (15%). Immediately after PTMC, there were significantly reduced (p = 0.0001) left atrial pressure (24.2 +/- 5.6 to 15.1 +/- 5.1 mm Hg), mean pulmonary artery pressure (39.7 +/- 13.0 to 30.6 +/- 10.9 mm Hg) and mitral valve gradient (13.0 +/- 5.1 to 5.7 +/- 2.6 mm Hg). Mitral valve area increased from 1.0 +/- 0.3 to 2.0 +/- 0.7 cm2 (p = 0.0001) and cardiac output from 4.4 +/- 1.4 to 4.7 +/- 1.2 liters/min (p less than 0.01). The results mirrored clinical improvements in 209 patients (97%). Multivariate analysis showed an echo score greater than 8, and valvular calcification and severe subvalvular lesions as independent predictors for suboptimal hemodynamic results.(ABSTRACT TRUNCATED AT 250 WORDS)
Natural killer (NK) cell activity was studied serially in the peripheral blood obtained from 35 patients with recurrent aphthous ulcers (RAU) and from 46 age/sex-matched normal healthy controls. The NK cell activity was assayed by a 4-hr 51Cr release assay using K562 cells as targets. The results showed that the patients in remission (2 weeks of convalesence) had normal NK cell activity compared to that of normal controls. Four stages of evolution (early, exacerbation, postexacerbation, and convalescence) in these patients were further evaluated. Increased NK cell activity in the exacerbation of major aphthous ulcer was noted. In contrast, depressed NK cell activity in postexacerbation and in 1 week of convalescence was found at different effector/target (E/T) ratios. The depressed NK cell activity was interpreted as temporary and a secondary phenomenon in the immunopathogenesis of this disease. Partial restoration of depressed NK cell activity by adding recombinant interleukin-2 (rIL-2) suggests that other factors are also involved in the process or that IL-2 deficiency exists in RAU patients. However, no deficiency of plasma IL-2 and interferon-gamma (IFN-gamma) was noted. The percentage of large granular lymphocytes (LGL, NK/K) was correlated with NK cell activity, with both parameters being depressed in the postexacerbation of RAU patients. NK cell activity of RAU patients was still depressed after the depletion of plastic adherent cells. Suprisingly, in contrast to the remission stage, unresponsiveness to rIL-2 of normal NK cell activity in the exacerbation stage was found. The discrepancy was not associated with different subpopulations of NK heterogeneous cells. Immunopathogenesis of RAU on the NK-IFN-IL-2-IL-2R system needs further clarification.
The frequency of HLA-DR and -DQ antigen occurrence was investigated in 80 Chinese patients with recurrent oral ulcers and 107 matched healthy control subjects of the same ethnic group. No significant differences in the presence of HLA-DQ antigens were found. However, the HLA-DRw9 antigen occurs more frequently in patients with recurrent oral ulcers (p less than 0.0001, corrected p less than 0.005) and may be considered as a genetic marker of the disease in the Chinese population.
The use of intermittent positive-pressure ventilation via nasal mask with a rocking bed provided the necessary ventilatory support for a person with quadriplegia living at home. This option was required to maintain an independent life-style of choice. The combination of techniques and the linkage of devices demonstrated an effective use of simple available technology for respiratory care at home and the adaptation of the respiratory prescription to the total needs of each person: medical, social, and financial. The further use of nasal mask ventilation in selected cases is encouraged by clinical research protocol.
Cryofibrinogenemia, a rare disease, is diagnosed by the presence of reversible cryoprecipitate in plasma, which may cause various clinical manifestations of thromboembolic or hemorrhagic disorders. A 66-year-old female patient suffered from recurrent reticulate erythema, purpura and gangrene on the distal portion of the extremities and face during the winter for 5 years. Cryofibrinogenemia was proven with the following evidences: (1) Histopathologic findings revealed many eosinophilic cylinders, about 6-9 microns in diameter, deposited within the lumen of the blood vessels in the dermis and subcutaneous tissue. There was no evidence of vasculitis. These cylinders were fibrinogen in nature, as proven by direct immunofluorescence. (2) Cryofibrinogen was detected in the citrated plasma, which was confirmed by double immunodiffusion, the presence of an IgG-kappa M protein was also revealed by immunofixation. Debridement and skin grafts were performed, and prednisolone combined with cyclophosphamide were given. Skin lesions improved without recurrence, and the "cryocrit" decreased from 13.6% to less than 2% during the follow up. We conclude that if there is any case with the similar cutaneous manifestations, cryofibrinogenemia should be considered.
A continuous dimensional electrophoretic method was used in 15 urine samples of clinically diagnosed mucopolysaccharidoses I or IV. Twelve of the 15 were glycosaminoglycans band positive. Of the 12 one was KS band positive but methyl toluidine blue test was negative. The other 11 were positive with both methods. Prenatal diagnosis was done in 10 cases during their next pregnancy with the same method on the amniotic fluid. Two affected fetuses were diagnosed and proved, one after induced abortion and the other after full-term delivery.
Muscle pain syndrome is a complicated situation in that even an extensive work-up may overlook the primary etiology. A patient with multiple medical problems, including a history of partial gastrectomy due to trauma, a below-knee amputation from arteriosclerotic disease, and chronic phenytoin therapy for a seizure disorder, developed intractable, generalized muscle pain, with total dependency in mobility and self care. He was admitted to an acute care hospital and was eventually discharged with a diagnosis of occult malignancy. After being referred to our amputee clinic for prosthetic management, the patient was admitted for inpatient rehabilitation. Electrodiagnostic studies and muscle biopsy revealed typical neuropathic findings and nonspecific myopathic changes. Laboratory studies showed a vitamin D deficiency with secondary hyperparathyroidism. Discontinuation of phenytoin and treatment with calcium and vitamin D resulted in rapid relief of muscle pain and marked improvement in mobility and self care. This case illustrates an unusual combination of phenytoin-induced axonopathy and osteomalacia that incapacitated an otherwise functional person with below-knee amputation.
Three female patients of two generations in one family each had patent ductus arteriosus (PDA) that was proved by echocardiography and cardiac catheterization. Two of them received surgical ligation of the PDA because of large left to right shunt (Qp/Qs of 3.8 and 2.7, respectively), while the third patient with a Qp/Qs of 1.2 was not operated. Although the exact cause of PDA in this family is unclear, an autosomal recessive inheritance is highly possible.
This study was undertaken to identify the cutaneous manifestations among different prognostic subgroups of postthymic T cell malignancies. Cutaneous involvement was demonstrated in 43 of 88 cases. We recognized five clinicopathologic subtypes: type I, classical cutaneous T cell lymphoma (CTCL) or mycosis fungoides, six cases; type II, primary large cell type CTCL, Ki-1 antigen (Ki-1+ or Ki-1-), seven cases; type III, primary angioinvasive T cell lymphoma, three cases; type IV, human T-lymphotropic virus type I (HTLV-I+) adult T cell leukemia/lymphoma (ATL), eight cases; type V, secondary cutaneous involvement by peripheral T cell lymphoma (PTL), 19 cases. Primary CTCL and ATL tend to involve papillary dermis with or without epidermotropism, whereas PTL and angioinvasive T cell lymphoma predominantly affect skin adnexae, vessels, and subcutis. Cutaneous lesions in type V PTL are heterogeneous and may be confused with panniculitis, vasculitis, or an eczematous eruption. Classic CTCL, Ki-1+ lymphoma, and angioinvasive T cell lymphoma have a chronic course, whereas ATL, Ki-1- large cell lymphoma, and PTL are clinically aggressive.
We studied 128 children who were transplacentally exposed to polychlorinated biphenyls and dibenzofurans in Taiwan, their parents and siblings who were directly exposed, and 115 control children. Direct exposure of the mothers stopped in 1979 and the children were born as late as 1985. At birth, exposed children had increased rates of hyperpigmentation, eyelid swelling and discharge, deformed nails, acne, natal teeth and swollen gums compared to controls. On examination, they had a much higher rate of dystrophic finger-nails and pigmented or dystrophic toe-nails than controls. They also had an increased rate of hyperpigmentation and acne. In addition they had more generalized itching, localized skin infections and hair loss. The findings seen in transplacentally exposed children differ from those seen in people directly exposed, particularly in the latter group in higher prevalence of acne.
In a F12 medium supplemented with epidermal growth factor (20 ng/ml), insulin (5 micrograms/ml), transferrin (5 micrograms/ml), hydrocortisone (1 microM), cholera toxin (40 ng/ml), endothelial cell growth supplement (15 ng/ml) and retinoic acid (1 x 10(-7) M) on Vitrogen coated culture dishes, normal adult and newborn human foreskin keratinocytes were cultured for 4- and 2-time with population doublings (PD) accumulated as 8 and 12, respectively. The cells grown in this medium possessed a basaloid, undifferentiated and hyperproliferating nature, with a population doubling time of about 24 hours at early passage. Between the 1st and 2nd subcultures, cell proliferation was the most active. Delaying the time of first subculture lowered the rate of cell proliferation. The keratin of the cultured cells was studied by immunoblotting and revealed the presence of permanent keratin markers of the human skin (AE1 50 kDa and AE3 58kDa) as well as a relatively high intensity of a proliferating marker (AE1 48 kDa) and a relatively low intensity of a differentiation marker (AE3 67 kDa).
From January 1987 to December 1988, 100 patients with symptomatic severe rheumatic mitral stenosis underwent percutaneous transvenous mitral commissurotomy (PTMC). The patients included 32 males and 68 females, aged 19-71 years (mean of 41). Mild mitral regurgitation (grade 1 or 2) was present in 23 patients and a history of thromboembolism in 12. One patient had had mitral restenosis after surgical open mitral commissurotomy 9 years earlier. The mitral valve was successfully dilated in 97 patients. PTMC resulted in immediate improvements in hemodynamic measurements. The left atrial pressure decreased from 24.5 +/- 5.3 to 14.8 +/- 5.2 mmHg (p less than 0.001), the mean mitral transvalvular gradient from 13.8 +/- 4.8 to 5.0 +/- 2.8 mmHg (p less than 0.001), and the mean pulmonary artery pressure from 38.8 +/- 12.0 to 30.6 +/- 10.3 mmHg (p less than 0.001). The mitral valve area increased from 1.1 +/- 0.3 to 2.2 +/- 0.8 cm2 (p less than 0.001). The cardiac output increased from 4.5 +/- 1.2 to 4.84 +/- 1.2 L/min (p less than 0.05). The right atrial pressure did not change significantly after PTMC (6.5 +/- 3.8 vs 6.4 +/- 4.0 mmHg). The mitral valve area measured by 2-D echocardiograms increased from 1.04 +/- 0.48 to 1.88 +/- 0.66 cm2 after PTMC (p less than 0.001). All 97 patients were followed for 6-24 months (median of 13) after the PTMC. After an initial recovery period of 1-2 weeks, all patients reported improvements in symptoms and in New York Heart Association (NYHA) functional class by at least one class. A comparison between treadmill exercise test durations before, and 3 months after PTMC, showed an increase from 9.1 +/- 4.3 to 15.4 +/- 3.8 minutes (n = 60; p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)
Percutaneous transvenous mitral commissurotomy (PTMC) for severe, symptomatic mitral stenosis was successfully performed in 47 of 50 patients with pliable, non-calcified valves. The procedure resulted in immediate hemodynamic and sustained clinical improvements in all patients. Repeat cardiac catheterization was performed in 22 patients at a mean follow-up period of 15 months (range 12 to 29). The patients were similar to the other 25 patients in regard to gender, age, clinical and hemodynamic characteristics. There were 4 males and 18 females with a mean age of 37 years (range 20 to 61). Immediately after PTMC, there were significant increases in the mitral valve area (1.0 +/- 0.2 to 2.4 +/- .9cm2, p less than 0.001) and cardiac index (3.1 +/- 0.7 to 3.3 +/- 0.7 l/min/m2, p less than 0.05) and significant (p less than 0.001) decreases in the left atrial pressure (25.7 +/- 6.4 to 13.2 +/- 3.9 mmHg), the mitral valve gradient (15.7 +/- 5.7 to 3.9 +/- 1.4 mmHg), mean pulmonary arterial pressure (41.5 +/- 10.7 to 29.2 +/- 10.9 mmHg) and the pulmonary vascular resistance (4.2 +/ 3.4 to 3.5 +/- 2.9 Wood unit). At follow-up study, the mitral valve area (2.2 +/- 0.7 cm2) and the left atrial pressure (12.6 +/- 3.7 mmHg) remained unchanged. There were further decreases in the mean pulmonary arterial pressure (22.4 +/- 5.9 mmHg, p less than 0.05) and the pulmonary vascular resistance (2.0 +/- 1.5 Wood unit, p less than 0.05). There were significant (p less than 0.05) increases in the mitral valve gradient (6.6 +/- 2.5 mmHg) and the cardiac output (3.6 +/- 0.7 l/min/m2).(ABSTRACT TRUNCATED AT 250 WORDS)