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Biomedical subjects

M L Wang

Publications and source records attributed to M L Wang.

At least 19 recordsLinked to original sources
PubMed2001

Two new bislabdane-type diterpenoids and three new diterpenoids from the roots of Cunninghamia lanceolata.

Two new bislabdane-type diterpenoids lanceolatin (1), lancelatol (2) and three new diterpenoids 15-nor-14-oxo-8(17),12-labdanien-14,18-dionic acid (3), 8(17),12,14-labdantrien-18-oic acid (4) and 8(17),12,14-labdantrien-18-ol (5), together with 7 known diterpenoids were isolated from the roots of Cunninghamia lanceolata. Their structures were determined by spectroscopic and chemical methods. All of these compounds were isolated from the species for the first time. One of the isolated compounds showed a significant inhibition effect on mouse hind-paw edema induced by carrageenan.

Animals↗
PubMed2001

Chemical constituents from the leaves of Magnolia denudata.

20 compounds were isolated from the leaves of Magnolia denudata including 16 lignans, which belong to 6 structural types. Except for (7R, 8S, 1'S)-delta8' -1', 4'- dihydro-5'-methoxy-3,4-methylenedioxy-4'-oxo-7.0.2', 8.1'-neolignan (6), magliflonenone (9), 2, 5'-diene-2', 8'-epoxy-5'-methoxy-8-methyl-4'-oxo-3,4- methylenedioxy-spiro (5, 5)-undecane (10), veraguensin (16) and beta-sitosterol (20), the other 15 compounds were obtained from this species for the first time. The absolute configurations of 3 compounds (1, 4, 10) were determined by CD spectroscopy for the first time. The anti-inflammatory activities of compounds 1, 2 and 16 were assessed and 2 was shown to have significant inhibition effect on mice hind-paw edema induced by carrageenan.

Animals↗
PubMed2001

Capecitabine for 5-fluorouracil-resistant brain metastases from breast cancer.

We report a case in which brain metastases originating from breast cancer responded to treatment with oral capecitabine. The metastases had progressed and Karnofsky performance status deteriorated despite whole brain irradiation, hormonal treatment, and systemic chemotherapy that included 5-fluorouracil (5-FU). In contrast, 2 months of treatment with oral capecitabine produced a partial response, documented by lesion size on magnetic resonance imaging and an improvement in performance status; both measures continued to improve during 11 months of capecitabine treatment.

Adult↗
PubMed2001

Rapid declines in FEV1 and subsequent respiratory symptoms, illnesses, and mortality in coal miners in the United States.

Coal mine dust exposure is associated with accelerated loss of lung function. We assessed long-term health outcomes in two groups of underground coal miners who during previous mine surveys had shown either high rates of FEV1 decline (cases, n = 310) or relatively stable lung function (referents, n = 324). Cases and referents were matched initially for age, height, smoking status, and FEV1. We determined vital status for 561 miners, and obtained a follow-up questionnaire for 121 cases and 143 referents. Responses on the follow-up questionnaire were compared with those on the last previous mine health survey questionnaire. Cases showed a greater incidence of symptoms than did referents for cough, phlegm production, Grades II and III dyspnea, and wheezing, and greater incidences than referents of chronic bronchitis and self- reported asthma and emphysema. More cases than referents (15% versus 4%) left mining before retirement because of chest illnesses. After controls were applied for age and smoking, cases had twice the risk of dying of cardiovascular and nonmalignant respiratory diseases and a 3.2-fold greater risk of dying of chronic obstructive pulmonary disease than did referents. Rapid declines in FEV1 experienced by some coal miners are associated with subsequent increases in respiratory symptoms, illnesses, and mortality from cardiovascular and nonmalignant respiratory diseases.

Coal Mining↗
PubMed2001

Efficacy trial of Vi polysaccharide vaccine against typhoid fever in south-western China.

OBJECTIVE: To test the efficacy of locally produced Vi vaccine over a time period of longer than one year. METHODS: A double-blinded, randomized field trial was performed in Guangxi Zhuang Autonomous Region in south-western China, using 30 micrograms doses of locally produced Vi. Enrolled subjects were 3-50 years of age, although the majority (92%) were school-aged children, who have the highest rate of typhoid fever in this setting. A total of 131,271 people were systematically allocated a single dose of 30 micrograms of Vi polysaccharide or saline placebo. The study population was followed for 19 months, with passive surveillance conducted in the Ministry of Health and the Regional Health and Anti-epidemic Centre (HAEC). Clinically suspected cases of typhoid fever were confirmed by blood culture, or by serological reaction with O-antigen (Widal tests). FINDINGS: After 19 months, there were 23 culture-confirmed cases of typhoid fever in the placebo group versus 7 cases in the Vi group (Protective efficacy (PE) = 69%; 95% CI = 28%, 87%). Most of the isolates were from school-aged children: 22 cases in the placebo group versus 6 in the Vi group (PE = 72%; 95% CI = 32%, 82%). No serious post-injection reactions were observed. The locally produced Vi polysaccharide vaccine showed levels of protective efficacy similar to those for Vi vaccine produced in industrial countries. CONCLUSION: The slightly higher dose of vaccine did not seem to alter efficacy significantly in China.

Adolescent↗
PubMed2000

Comparative fluorescence in situ hybridization mapping of a 431-kb Arabidopsis thaliana bacterial artificial chromosome contig reveals the role of chromosomal duplications in the expansion of the Brassica rapa genome.

Comparative genome studies are important contributors to our understanding of genome evolution. Most comparative genome studies in plants have been based on genetic mapping of homologous DNA loci in different genomes. Large-scale comparative physical mapping has been hindered by the lack of efficient and affordable techniques. We report here the adaptation of fluorescence in situ hybridization (FISH) techniques for comparative physical mapping between Arabidopsis thaliana and Brassica rapa. A set of six bacterial artificial chromosomes (BACs) representing a 431-kb contiguous region of chromosome 2 of A. thaliana was mapped on both chromosomes and DNA fibers of B. rapa. This DNA fragment has a single location in the A. thaliana genome, but hybridized to four to six B. rapa chromosomes, indicating multiple duplications in the B. rapa genome. The sizes of the fiber-FISH signals from the same BACs were not longer in B. rapa than those in A. thaliana, suggesting that this genomic region is duplicated but not expanded in the B. rapa genome. The comparative fiber-FISH mapping results support that chromosomal duplications, rather than regional expansion due to accumulation of repetitive sequences in the intergenic regions, played the major role in the evolution of the B. rapa genome.

Arabidopsis↗
PubMed2000

Simultaneous occurrence of multiple aetiologies of polycythaemia: renal cell carcinoma, sleep apnoea syndrome, and relative polycythaemia in a smoker with masked polycythaemia rubra vera.

A 58 year old male heavy smoker presented with intracranial haemorrhage and erythrocytosis. Four aetiologies of polycythaemia--polycythaemia rubra vera (PRV), renal cell carcinoma, sleep apnoea syndrome, and relative polycythaemia--were found to be associated with the underlying causes of erythrocytosis. He did not fulfill the diagnostic criteria for PRV at initial presentation, but an erythropoietin independent erythroid progenitor assay identified the masked PRV, and the low post-phlebotomy erythropoietin concentration also suggested the likelihood of PRV evolution. This case demonstrates that a search for all the possible causes of erythrocytosis is warranted in patients who already have one aetiology of polycythaemia.

Carcinoma, Renal Cell↗
PubMed2000

Design strategies for longitudinal spirometry studies: study duration and measurement frequency.

Measuring the longitudinal change in FEV(1) is useful for assessing the adverse effects of respiratory exposures and pulmonary diseases. Investigators seek to estimate the "true" mean FEV(1) slope (mu(beta)) of an infinite population. The difference between the estimated mean FEV(1) slope (mu(beta)) and the true mean slope, resulting from biological variation and measurement errors, can be minimized by increasing the number of subjects (N), years of follow-up (D), or the frequency of measurements (P). We defined maximum error e(max) such that P[|mu(beta) - mu(beta)| < or = e(max)] = 0.95, and thus e(max) is one-half the width of the 95% confidence interval for mu(beta). We computed the values of e(max) on the basis of actual data obtained from 160 coal miners and working nonminers who had completed 11 spirometry measurements, using recommended equipment and procedures, at 6-mo intervals over 5 yr. Individual 5-yr FEV(1) slopes (Delta FEV(1)) were calculated by linear regression. For a range of values of N, D, and P, tables are provided for e(max), the magnitude of detectable differences in Delta FEV(1) between two groups, and the recommended number of subjects needed in each of two groups to reliably detect the anticipated differences in Delta FEV(1). The tables provide unique guidance for investigators in selecting among various study design options.

Adult↗
PubMed2000

Asthma-like symptoms in wood product plant workers exposed to methylene diphenyl diisocyanate.

BACKGROUND: Diisocyanates, a group of highly reactive chemicals, have frequently been associated with occupational asthma. We evaluated respiratory health in workers at a new wood products manufacturing plant that uses methylene diphenyl diisocyanate (MDI), and was designed and operated with a goal of minimizing worker exposures. METHODS: Health surveys using standardized respiratory questionnaires were done prior to the initial use of diisocyanates in the plant, and semiannually thereafter for a period of 2 years. Other testing included occupational and work practice histories, serial peak flow measurements, spirometry, methacholine challenge, and measurement of specific IgE antibodies to MDI-albumin conjugate. RESULTS: Of 214 plant employees who participated in at least one health survey, a follow-up survey was also available from 178 employees (83%). New-onset asthma-like symptoms (NAS) were reported by 15 of 56 workers (27%) in areas with the highest potential for exposures to liquid MDI monomer and prepolymer, vs 0 of 43 workers in the lowest potential exposure areas (p = 0.001). In the areas with high potential exposure, NAS developed in 47% of workers who had noted MDI skin staining, vs 19% without skin stains (p = 0.07). Working around and cleaning up liquid MDI represented a significant risk for asthma-like symptoms in both current smokers and nonsmokers; work with finished wood products did not. Asthma-like symptoms were associated with variable airflow limitation (odds ratio [OR], 5.0; confidence interval [CI], 1.4 to 18.7) and specific IgE to MDI-albumin (OR, 3.2; CI, 1.1 to 9.0), but not with skin prick tests to common aeroallergens (OR, 1.1; CI, 0.5 to 2.7). CONCLUSIONS: During the first 2 years of operation, in a plant designed and operated to control exposure to diisocyanates, the development of asthma-like symptoms was reported in a relatively high proportion of the employees who worked with liquid MDI. To prevent asthma symptoms among workers, careful control of respiratory tract exposures associated with liquid MDI is important, especially during cleanup activities. Strict limitation of skin contact with diisocyanates may also be necessary.

Adult↗
PubMed2000

Major hematological diseases associated with cleft lip and palate.

OBJECTIVE: Cleft lip and palate is among the most common congenital anomalies. Its association with major blood disorders has rarely been reported. The purpose of this study was to report two patients who had major blood diseases associated with cleft lip and palate. PATIENTS AND RESULTS: From June 1995 to December 1997, there were 2700 patients with cleft lip, cleft palate, or both who received treatment at Chang Gung Memorial Hospital. Two of them were found to have major hematological disorders. In both cases, the disorder was detected by preoperative blood cell counts and white cell differentiation. Case 1 was a 21-year-old woman patient with repaired right cleft lip. She was admitted for alveolar bone grafting and closure of oronasal fistula. Abnormal presentation of blast cells was found, and subsequent bone marrow study confirmed acute lymphocytic leukemia. Case 2 was a 26-year-old man with left secondary cleft lip nasal deformity scheduled to receive staged reconstructive operations. An elevated platelet count was found and subsequently confirmed to represent essential thrombocytosis. In both cases, reconstructive operations for the cleft-related deformities were performed. CONCLUSIONS: Association of major hematological disorders and cleft lip, palate, or both is rare and is reported herein.

Adult↗
PubMed2000

Significance of nitrogen removal mass in uremic patients on different modalities of dialysis therapy.

BACKGROUND AND PURPOSE: While most nephrologists use Kt/V values for dialysis prescriptions, some researchers are beginning to view the role of solute removal mass as an indicator of adequate dialysis. This study, using nitrogen as a surrogate for solute removal, probed whether solute removal mass can be used as the target of adequate dialysis. Mathematical formulas for easy bedside calculation of nitrogen removal mass were used to avoid the problems associated with direct measurement. METHODS: The weekly removal mass of urea nitrogen (M) and the urea generation rate (G) of 32 conventional hemodialysis (HD) and 21 continuous ambulatory peritoneal dialysis (CAPD) patients were calculated. All the patients were anuric, clinically stable, and under adequate dialysis pursuant to either the criterion of the urea index, Kt/V, or clinical requirements. RESULTS: The difference in MHD (MHD = 41.9 +/- 9.5 g/week, MCAPD = 38.8 +/- 11.9 g/week) and G (GHD = 3.90 +/- 1.02 mg/min, GCAPD = 3.85 +/- 1.21 mg/min) between the two groups was statistically insignificant (p = 0.119 and p = 0.868, respectively). When protein nitrogen leaking through the peritoneal membrane was considered and added to MCAPD, nitrogen removal in CAPD patients (M'CAPD = 42.3 +/- 13.0 g/week) approached that in HD patients (p = 0.886). There was no correlation between dialysis dosage and urea removal mass in either the CAPD or HD groups. CONCLUSIONS: Urea nitrogen removal mass is similar to the protein catabolic rate (PCR) in stable patients. It is meaningful in dialysis evaluation only when it is used simultaneously with blood urea nitrogen measurement. However, because M changes at the inception of dialysis, it more significant than PCR in the evaluation of unstable patients.

Adult↗
PubMed2000

Meningeal involvement in B-cell chronic lymphocytic leukemia: report of two cases.

Symptomatic central nervous system (CNS) involvement in chronic lymphocytic leukemia (CLL) or its variants is rare. We report two cases of CLL with leptomeningeal involvement. Patient one was an 81-year-old male who had CLL stage C (IV) at diagnosis and developed meningeal disease 29 months later. Patient 2 was a 42-year-old male with a diagnosis of CLL stage A (II) that evolved into mixed-cell CLL/prolymphocytic leukemia (PLL) 1.5 years later, with leptomeningeal infiltration of prolymphocytes developing 26 months after initial diagnosis. Meningeal leukemia was diagnosed by cerebrospinal fluid examination, with flow cytometry showing the same immunophenotypic findings of lambda-light chain restriction as the lymphocytes in bone marrow in one patient, and with morphologic characteristics exhibiting exclusively prolymphocytes in the other patient. The CNS disease of both patients responded effectively to intrathecal chemotherapy and cranial irradiation. However, both patients died of infection, a major cause of morbidity and mortality in patients with CLL. The clinicopathologic features of these two patients indicate that, despite the rarity of CNS involvement in CLL patients, any neurologic manifestation in CLL patients should arouse suspicion of meningeal leukemia and patients should be examined and managed accordingly.

Adult↗
PubMed1999

Free medialis pedis flap as a coverage and flow-through flap in hand and digit reconstruction.

BACKGROUND: Skin and soft-tissue defects of the hand and digit present a challenge for the hand surgeon especially in meeting the reconstructive needs of thickness, texture, color matching, and sensation. It becomes an even bigger challenge to reconstruct the defect in a devascularized finger with segmental loss of the neurovascular bundle. We use the relatively new flap, the medialis pedis flap, to solve the above conditions and compare it with traditional flaps. METHODS: From May of 1994 to March of 1997, the free medialis pedis flap was used to reconstruct 19 digit and hand defects; the flap sizes ranging from 1.5 x 3.0 cm to 3.0 x 9.0 cm. Sixteen flaps were used for simple coverage of digit defects, including 12 for single-digit and 4 for multiple-digit reconstruction. The remaining three flaps were used as coverage and a flow-through flap for devascularized fingers. RESULTS: All 19 flaps survived and achieved a good protective sensation. The appearance was very satisfactory, and the donor-site scars were without sensory problems. CONCLUSION: Compared with traditional flaps, the free medialis pedis has the following advantages: it provides good thickness, texture, and color matching for hand and digit resurfacing; it can be used as a flow-through flap and as coverage for a devascularized finger in a one-stage procedure; the size of the feeding vessels of the flap matches those of the digital vessels well; and it consists of glabrous skin rich in nerve endings, so it has good potential for sensory recovery. Because of all of these characteristics, the free medialis flap may become a better consideration for hand surgeons.

Adult↗
PubMed1999

Chest illnesses and the decline of FEV1 in steelworkers.

This study relates the impact of various medical conditions to clinically important forced expiratory volume in 1 second (FEV1) declines in a cohort of steelworkers evaluated cross-sectionally and longitudinally. Medical records of 1171 randomly chosen steelworkers were obtained from the medical department of a steel company. We reviewed the medical records for information regarding demographic parameters, smoking status, spirometry indexes, job history, and the worker's respiratory health. These workers had performed annual spirometry from 1980 to 1991 at least once and up to 12 times. We compared the prevalence of medical conditions in 203 male never-smoking steelworkers in this group of 1171 workers by separating workers into three groups on the basis of final predicted FEV1 values (< 65%, between 65% and 79%, and > or = 80%). We also evaluated the prevalence of medical conditions and the association between these conditions and the rate of annual decline in FEV1 in 475 steelworkers who had at least three valid tests and at least 5 years separating the first and last test by multiple logistic regression analysis. Of the 475 steelworkers, 121 were categorized as rapid decliners (an annual rate of decline in FEV1 exceeding the 75th percentile of the slope distribution), whereas the remaining workers served as controls. Three of 203 and 17 of the remaining 200 in the cross-sectional survey had final predicted FEV1 values < 65% or between 65% and 79%, respectively. Among these 20 never-smokers, the accelerated rate of decline could be reasonably explained by factors independent of dust and age in all but two. In the 203 never-smokers, hay fever and trauma occurred more frequently in those with a decreased predicted FEV1. In the longitudinal study of 475 workers, the prevalence of pneumonia was significantly greater in the rapid decliners, whereas the prevalence of allergy, asthma or hay fever, and trauma approached a significant excess in number. Logistic regression models demonstrated that aging, weight gain, smoking, trauma, pneumonia, and a history of allergy, asthma, or hay fever were independently related to the risk of a clinically important decline of FEV1 in this group. In summary, there are multiple risk factors for an accelerated rate of decline in workers with dust exposure. An accurate assessment of the causes for an excessive rate of lung function decline in an individual worker within a population requires an understanding of the relationship between environmental exposures, lung function decline, and the individual worker's underlying health. In addition to the three traditionally recognized variables--age, smoking, and dust exposure--the medical conditions of trauma, pneumonia, and allergy, asthma, or hay fever were related to a clinically important decline of FEV1 in this industrial population.

Adult↗
PubMed1999

Clinically important FEV1 declines among coal miners: an exploration of previously unrecognised determinants.

OBJECTIVES: The relation between occupational exposure to dust and loss of ventilatory lung function is now well established. However, many exposures during work and other activities might also have important roles in determining clinically important losses of lung function. In this study, we attempted to explore additional plausible determinants of exposures and other potential risk factors for clinically important decline in forced expiratory volume in 1 second (FEV1) during work in dusty trades. METHODS: The study was performed in 264 underground coal miners whose lung function had been followed up for an average of 11 years. With an extensive follow up questionnaire, miners were asked about their occupational and non-occupational exposures, smoking, personal and family medical history, and living conditions during childhood. RESULTS: Several variables of the mine environment (as well as previously recognised effects of mining work and region) were found to be associated with excess decline in FEV1, including work in roof bolting, exposure to explosive blasting, and to control dust spraying water that had been stored in holding tanks. Use of respiratory protection seemed to reduce the risk of decline in FEV1. Other factors that were found to be associated with declines in pulmonary function included smoking, body mass, weight gain, childhood pneumonia, and childhood exposure in the home to passive tobacco smoke and possibly smoke due to wood and coal fuels. Miners with excessive decline in FEV1 were less likely to be working in mining jobs at follow up. CONCLUSIONS: These findings suggest the existence of additional risk factors for decline in lung function in dusty trades, and may be useful in developing additional approaches to the prevention of chronic respiratory disease.

Adult↗