Biomedical subjects

W J Chen

Publications and source records attributed to W J Chen.

At least 55 records · Page 3Linked to original sources

PubMed2001

Lateral collateral ligament reconstruction using quadriceps tendon-patellar bone autograft with bioscrew fixation.

The lateral collateral ligament is the primary stabilizer against varus stress and is also an important contributor in maintaining posterolateral knee stability. Quadriceps tendon-patellar bone autograft has been used for anterior or posterior cruciate ligament reconstruction. We introduce a reconstructive procedure to restore the lateral collateral ligament using a quadriceps tendon-patellar bone autograft. The procedure is designed for unstable knees with concomitant cruciate ligament tear and posterolateral complex injury. This is a reasonable choice especially when allograft tissue is not available or in patients who are not suited for the use of bone-patellar tendon-bone autograft.

Arthroscopy↗

PubMed2001

IL-6 inhibits apoptosis and retains oxidative DNA lesions in human gastric cancer AGS cells through up-regulation of anti-apoptotic gene mcl-1.

Apoptosis plays a critical role in maintaining genomic integrity by selectively removing the most heavily damaged cells from the population. Reactive oxygen species (ROS) and certain inflammatory cytokines are always elevated during the human carcinogenic process. However, the biological significance of the interplay between ROS and inflammatory cytokine remains elusive. This study demonstrates that interleukin-6 (IL-6) effectively protects gastric cancer cells from the apoptosis induced by hydrogen peroxide (H(2)O(2)). The cell death signaling JNK pathway elicited by H(2)O(2) is also inhibited by IL-6. We further found that Mcl-1, but not other Bcl-2 family members, was up-regulated by IL-6, by a substantial level over 24 h. We further transfected a mcl-1 expression vector, pCMV-mcl-1, into the AGS cells, and successfully obtained several mcl-1-overexpressing clones. Flow cytometric analysis shows that these mcl-1-overexpressing AGS cells are more resistant to the apoptosis induced by H(2)O(2) when compared with the neo control AGS cells. Consistently, the activation of the JNK pathway induced by H(2)O(2) is also blocked in mcl-1-overexpressed cells. These results indicate that the anti-apoptotic effect of IL-6 is, at least in part, due to the up-regulation of mcl-1. To our surprise, either IL-6 exposure or mcl-1 overexpression fails to reduce the level of intracellular peroxides in the AGS cells triggered by H(2)O(2). This study also determined the level of 8-hydroxydeoxyguanosine (8-OH-dGua), an indicator for oxidative DNA lesions in IL-6-treated or mcl-1-overexpressed AGS cells after treatment with H(2)O(2). Notably, our results indicate that a majority of the 8-OH-dGua is efficiently removed in the AGS cells without IL-6 treatment, whereas only approximately 50% of the 8-OH-dGua was repaired in the IL-6-treated AGS cells after 24 h. Similarly, approximately 60-70% of the 8-OH-dGua also failed to repair and was retained in the genomic DNA of the mcl-1 transfectants. Results in this study provide a novel mechanism by which up-regulation of the Mcl-1 protein by IL-6 may enhance the susceptibility to H(2)O(2)-induced oxidative DNA lesions by overriding apoptosis.

8-Hydroxy-2'-Deoxyguanosine↗

PubMed2001

Functional relevance of human adh polymorphism.

This article represents the proceedings of a symposium at the 2000 ISBRA Meeting in Yokohama, Japan. The chairs were C. J. Peter Eriksson and Tatsushige Fukunaga. The presentations were (1) 4-Methylpyrazole as a tool in the investigation of the role of ADH in the actions of alcohol in humans, by Taisto Sarkola and C. J. Peter Eriksson; (2) ADH2 polymorphism and flushing in Asian populations, by Wei J. Chen, C. C. Chen, J. M. Ju, and Andrew T. A. Cheng; (3) Role of ADH3 genotypes in the acute effects of alcohol in a Finnish population, by Hidetaka Yamamoto, Kathrin Kohlenberg-Müller, and C. J. Peter Eriksson; (4) Clinical characteristics and disease course of alcoholics with different ADH2 genotypes, by Mitsuru Kimura, Masanobu Murayama, Sachio Matsushita, Haruo Kashima, and Susumu Higuchi; (5) ADH2 polymorphism, alcohol drinking, and birth defects, by Lucinda Carr, D. Viljoen, L. Brooke, T. Stewart, T. Foroud, J. Su, and Ting-Kai Li; and (6) ADH genotypes and alcohol use in Europeans, by John B. Whitfield.

Adult↗

PubMed2001

Rates and patterns of comorbidity of adolescent behavioral syndromes as reported by parents and teachers in a Taiwanese nonreferred sample.

OBJECTIVE: To evaluate the rates and patterns of comorbidity between behavioral syndromes in adolescents as reported by parents and teachers. Whether the patterns of comorbidity were "epiphenomenal" was also assessed. METHOD: Parents of 854 randomly selected students (response rate = 88%) in Taipei in 1996 completed the Child Behavior Checklist; among them, 240 also were randomly selected to have the Teacher's Report Form completed by their teachers. In addition to bidirectional comorbidity rates, odds ratios with and without other comorbid pairs controlled for were estimated via multiple logistic regressions. RESULTS: High comorbidity rates between behavioral syndromes were found in adolescents as reported both by parents and teachers except for that of Somatic Complaints with other syndromes. When other comorbidity pairs were controlled for, the comorbidity rates between Anxious/Depressed with externalizing syndromes turned out to be epiphenomenal, whereas those between externalizing syndromes remained high for both informants' reports. Attention Problems also remained significantly comorbid with other syndromes in the multiple logistic regressions except for that of Aggressive Behavior in the Teacher's Report Form sample. CONCLUSION: High comorbidity rates between adolescent behavioral syndromes exist in both parents' and teachers' reports, and it is important to control for the epiphenomenal condition when assessing such comorbidity rates.

Adolescent↗

PubMed2001

Genetic polymorphisms of the promoter region of dopamine D2 receptor and dopamine transporter genes and alcoholism among four aboriginal groups and Han Chinese in Taiwan.

This study aims to examine the relationship between the functional polymorphism at the promoter region of the dopamine D2 receptor (DRD2) gene (i.e. -141C Ins/Del) and variable number of tandem repeat polymorphism at the 3' untranslated region of the dopamine transporter (DAT) gene (SLC6A3) with alcoholism in a case-control study. The cases (n = 203) were alcohol dependents with withdrawal symptoms, and the controls (n = 213) were sex- and ethnicity-matched individuals who were screened to exclude those with alcohol problems among four aboriginal groups (Atayal, Ami, Bunun, and Paiwan) and Han Chinese in Taiwan. To control for potential confounding factors, we excluded tobacco abusers from control subjects in part of the analysis and compared the distribution of the genetic polymorphisms in alcoholics with severe medical complications versus those with less severe medical complications. There were no differences in allele and genotype frequencies of these two distinct genetic markers between alcoholics and control subjects in these five different ethnic groups. There was no significant linkage disequilibrium between the -141C polymorphism and two other DRD2 polymorphisms (TaqI A and NcoI). The results remained unchanged when cases were limited to alcoholics with more severe medical complications or when tobacco abusers were excluded from control subjects. The results suggest that both the DRD2 promoter region and the DAT gene do not play a significant role in conferring vulnerability to alcoholism.

Adult↗

PubMed2001

Cystic malignant fibrous histiocytoma of the gastrocolic ligament.

A case of malignant fibrous histiocytoma (MFH) of the gastrocolic ligament is presented. It appeared as a huge, thin walled cystic tumour in the upper abdominal cavity on CT. Barium studies showed splaying of the stomach and transverse colon by the mass. 1 year after resection of the cystic tumour, recurrence occurred at the greater curvature of the stomach and in the liver, with a cystic appearance similar to the primary tumour. To our knowledge, the CT appearance of primary cystic MFH of the gastrocolic ligament has not been previously documented.

Abdominal Neoplasms↗

PubMed2001

Effect of lanthanide chloride on photosynthesis and dry matter accumulation in tobacco seedlings.

To investigate the physiological effects of rare earth ions, we have studied the effect of LaCl3 on the photosynthetic light reactions in tobacco (Nicotiana tobacum). When treated with 5-20 mg/L LaCl3 in Hoagland solution by water culture, the dry matter accumulation of different parts in tobacco, the content of chlorophyll increased gradually, but decreased when the concentration of LaCl3 was > or = 50 mg/L. The optimum concentration for growth appeared to be about 20 mg/L of LaCl3 in nutrient solution. La3+ promoted the activities of the Hill reaction, Mg2(+)-ATPase, and stimulated the rate of photophosphorylation in chloroplast at low concentrations, but inhibited them at high concentrations. It is concluded that La3+ stimulated the growth of tobacco seedlings and accelerated the photosynthetic light reactions at suitable concentration in vivo.

Ca(2+) Mg(2+)-ATPase↗

PubMed2001

The EXAFS study on the local structure of lanthanum in spinach PSII.

The complex of photosystem II (PSII) had been prepared from spinach by treatment with Triton X-100. The PSII, which had been depleted of the extrinsic 17- and 23-kDa polypeptides, was obtained by exposing the solution to a high concentration of NaCl, and the complex of PSII-La3+ was prepared by treatment with LaCl3. The result indicated that La3+ could inhibit the oxygen-evolution activity of PSII by replacing the Ca2+. The local structural environment of La in PSII has been also studied by using extended X-ray absorption fine structure (EXAFS). The primary result of EXAFS indicated that La coordinated with eight oxygen and/or nitrogen atoms, with the distance of the La-O/N bond being 2.5 A. In addition, La coordinated with four carbon atoms, with a distance of 3.5 A in the second shell. In the third shell, La coordinated with two manganese atoms, with the distance of La-Mn bond being 4.49 A, and it was also found that the La-Mn distance (4.49 A) was longer than that of Ca-Mn (3.3 A) (1) in PSII.

Calcium↗

PubMed2001

Tension-band technique for ankle fusion.

A prospective study was conducted to develop a better technique for ankle fusion. Eleven consecutive patients were treated using the tension-band technique for ankle fusion and underwent follow-up for a minimum of 2 years (range: 2-5 years). All 11 patients achieved solid fusion for a fusion rate of 100%. Average time to fusion was 3 months (range: 2-6 months). The indication for ankle fusion was intractable aching pain that could not be controlled by conservative methods. Two of 11 patients underwent surgery due to infected arthritis. After ankle fusion, there was no recurrence of infection during a 3-year follow-up period. The technique included osteotomy of the bimalleoli from the inside out, removal of articular cartilage and preserving wedge space for cancellous bone grafting, with or without staple stabilization, and external immobilization supplementation. The functional outcome in all 11 patients improved from unsatisfactory preoperatively to satisfactory at latest follow-up (P<.001). No significant complications were noted. This simple technique proved excellent for ankle fusion with a satisfactory outcome and is recommended for treating severe ankle arthropathies.

Adult↗

PubMed2001

Third trimester binge ethanol exposure results in fetal hypercapnea and acidemia but not hypoxemia in pregnant sheep.

BACKGROUND: The mechanisms by which maternal ethanol abuse during pregnancy causes neurodevelopmental injury in the fetus are not well understood. The purpose of this study was to use a chronically instrumented fetal sheep model system to determine if a binge pattern of ethanol exposure administered throughout the third trimester reduced fetal arterial partial pressure of oxygen (PaO2); a positive finding would support the hypothesis that fetal hypoxemia may play a role in mediating ethanol-related birth defects. METHODS: Pregnant ewes received saline or 0.75, 1.25, 1.5, or 1.75 g/kg of ethanol intravenously over 1 hr beginning on day 109 of gestation (term = 145 days) for 3 consecutive days per week followed by 4 days without exposure. The fetuses were surgically instrumented on day 113, and experiments were performed on days 118 or 132, the 6th and the 12th ethanol exposure, respectively. RESULTS: Ethanol infusions resulted in peak blood ethanol concentrations of 80.8 +/- 6.5, 182.5 +/- 13.5, 224.4 +/- 13.9, and 260.6 +/- 20.0 mg/dl +/- SEM (maternal) and 70.0 +/- 5.9, 149.7 +/- 9.0, 216.9 +/- 14.0, and 233.3 +/- 19.8 mg/dl +/- SEM (fetal) in response to the 0.75, 1.25, 1.5, and 1.75 g/kg doses, respectively. Maternal and fetal heart rate and maternal blood pressure increased whereas fetal blood pressure decreased in a dose-dependent manner in response to ethanol infusions. Maternal and fetal arterial pH decreased and arterial partial pressures of carbon dioxide increased in response to ethanol infusions. Maternal PaO2 decreased whereas fetal PaO2 did not change in response to ethanol infusions. CONCLUSIONS: A binge ethanol exposure paradigm, three consecutive days per week throughout the third trimester at ethanol doses that created blood ethanol concentrations commonly achieved by human ethanol abusers, resulted in changes in maternal and fetal heart rate, changes in blood pressure, hypercapnea, acidemia, and maternal, but not fetal, hypoxemia. We conclude that in an ovine model system, ethanol doses that create blood ethanol concentrations as high as 260 mg/dl do not result in fetal hypoxemia. Remaining issues to address with this model system are whether neurodevelopmental injuries that are associated with maternal ethanol abuse are mediated by a reduction in fetal cerebral blood flow, fetal hypercapnea, or acidemia.

Abnormalities, Drug-Induced↗

PubMed2001

Zinc supplementation does not attenuate alcohol-induced cerebellar Purkinje cell loss during the brain growth spurt period.

BACKGROUND: Alcohol-induced zinc deficiency is one of the mechanisms proposed as a cause of developmental brain damage associated with fetal alcohol syndrome. It is known that alcohol exposure during the brain growth spurt period leads to cerebellar Purkinje cell loss. Therefore, this study examined whether zinc supplementation was capable of preventing alcohol-induced Purkinje cell loss in the cerebellar vermis in a neonatal rat model system. METHODS: Sprague-Dawley rat pups were given alcohol (EtOH; 4.5 g/kg/day), zinc (Zn; 0.54 mg/ml diet; [10 times the regular diet Zn concentration]), or both from postnatal days (PD) 4 through 9 using the artificial-rearing paradigm. A gastrostomy control (GC) and a suckle control group (SC) also were included. All pups were killed on PD 10. Following perfusion, the cerebellar vermis was dissected and processed for stereological cell counting. The total number of Purkinje cells and the volume of the cerebellar vermis were determined. RESULTS: Alcohol produced a significant loss of Purkinje cells compared with that in the GC group (no EtOH and no Zn supplement). The zinc supplementation had no effect in attenuating alcohol-induced Purkinje cell loss in the cerebellar vermis. In fact, the serum zinc concentration data indicated higher zinc concentrations following either EtOH or Zn treatment. Interestingly, the GC group showed a significantly lower zinc concentration compared with the SC group, even though no significant difference in Purkinje cell numbers was observed between these two control groups. CONCLUSION: These findings indicate that alcohol exposure during the third trimester equivalent did not result in zinc deficiency in this neonatal rat model system, nor did zinc supplementation rescue the alcohol-induced Purkinje cell loss in the cerebellar vermis. These findings showed clearly that the serum zinc concentration was not correlated with Purkinje cell loss, suggesting that alcohol-induced loss of cerebellar Purkinje cells in this neonatal rat model system is independent of the availability of serum zinc.

Animals↗

PubMed2001

Calcific myonecrosis of the leg: a case report and review of the literature.

Calcific myonecrosis is a rare complication of the leg after trauma. It usually develops as a late sequelae of compartment syndrome. Only approximately 21 cases have been reported in the English literature. The reported cases mostly have involved the anterior compartment of the leg. The current authors report the case of a 49-year-old man with a huge mass that involved the anterior and posterior compartments of the leg 30 years after initial trauma. Soft tissue sarcoma was suspected initially. A secondary infection developed after open incisional biopsy. After extensive debridement and closure of the wound over antibiotic-impregnated cement beads and a suction drain followed by compressive dressings, there has been no recurrence of the lesion or infection.

Calcinosis↗

PubMed2001

Alcohol-mediated Purkinje cell loss in the absence of hypoxemia during the third trimester in an ovine model system.

BACKGROUND: Although the mechanisms that underlie fetal alcohol-induced neuronal loss have not been determined, hypoxia/hypoxemia has been considered a leading candidate. This study was designed to test the hypothesis that neuronal loss could occur in the developing brain in the absence of fetal hypoxemia. METHODS: Three groups of pregnant sheep were used: a control group, a binge-drinking group, and a pair-fed group. The alcohol and pair-fed animals were anesthetized on day 113 of pregnancy, and the mothers and fetuses were instrumented with arterial and venous catheters. All animals were killed on day 133. Stereological cell counting techniques were used to estimate the total number of Purkinje cells in the fetal cerebellum. RESULTS: Peak maternal and fetal blood alcohol concentrations did not produce fetal hypoxemia. Nevertheless, there was a 25% loss of Purkinje cells of the cerebellum in the alcohol-exposed fetuses compared with that in the pair-fed controls. The loss of neurons was not accompanied by microencephaly or a concomitant decrease in either cerebellar weight or volume of the fetal cerebellum. CONCLUSIONS: Neuronal loss can be observed after alcohol exposure during the third trimester equivalent in fetal sheep in the absence of alcohol-induced hypoxemia. Furthermore, cell loss in the absence of deficits in gross brain weight or regional brain volume indicates that the lack of gross brain volume deficits from magnetic resonance imaging techniques is not a reliable indication that the brain is unaffected by the alcohol exposure.

Algorithms↗

PubMed2001

Fetal and maternal sheep hypothalamus pituitary adrenal axis responses to chronic binge ethanol exposure during the third trimester equivalent.

BACKGROUND: We tested the hypothesis that in utero ethanol exposure results in changes in fetal and maternal adrenocorticotropin (ACTH) and cortisol during the third trimester equivalent, by using a chronically instrumented fetal sheep model. METHODS: Pregnant ewes received saline or ethanol intravenously 3 consecutive days per week from day 109 to day 132 of gestation. Fetal and maternal blood samples were collected on days 118 and 132. RESULTS: Maternal and fetal ACTH and cortisol values increased on days 118 and 132 of gestation in response to ethanol infusions that created blood ethanol concentrations (BECs) that are easily achievable by human drinkers. Peak ACTH and cortisol values were detected 30 to 60 min after peak BECs were achieved. CONCLUSIONS: Chronic ethanol exposure during the third trimester equivalent in sheep resulted in repeated activation of the hypothalamus-pituitary-adrenal axis in both the mother and fetus. Temporally, the patterns of maternal and fetal responses to ethanol infusion were similar. We conclude that ovine maternal ethanol exposure during the third trimester equivalent increases fetal ACTH and cortisol concentrations, hormonal responses that may play a role in mediating alcohol-related birth defects.

Adrenocorticotropic Hormone↗

PubMed2001

Nicotine decreases blood alcohol concentration in neonatal rats.

BACKGROUND: Our previous findings suggested that the intragastric coadministration of alcohol and nicotine to neonatal rats resulted in a significant decrease from the predicted peak blood alcohol concentration (BAC). We hypothesized that the coadministration of alcohol and nicotine would produce a nicotine dose-related decrease in peak BAC and a change in the BAC time curve profile. METHODS: Sprague-Dawley rat pups were given alcohol and nicotine simultaneously via intragastric infusion. Two sets of nicotine doses were used in two independent studies. The low doses of nicotine were examined after the study of high doses of nicotine administration because of the possible ceiling effects from these nicotine doses on lowering BACs. RESULTS: The results not only confirmed that the peak BAC was lowered by nicotine, but also generated new findings showing that the profile of BAC time curve was affected by these doses of nicotine. Concerns about possible ceiling effects led us to conduct another experiment to examine the effects of lower doses of nicotine on BACs. Those results showed a significant decline in BACs after cotreatment with 0.5 or 1 mg/kg nicotine and less robust changes on the BAC curve profiles. Although the nicotine dose at 0.25 mg/kg/day did not affect significantly the overall BAC profile, it did lower the peak BAC. CONCLUSIONS: Nicotine is capable of lowering the peak BAC among neonatal rat pups. Furthermore, the pattern of the BAC time curve seems to be more affected by high doses of nicotine.

Animals↗

PubMed2001

Computed tomography and angiography in hepatic tuberculosis mimicking liver tumor.

Tuberculosis is one of the most common and well-documented infectious diseases, with a vast variety of clinical manifestations. A case of isolated hepatic tuberculosis mimicking liver tumor is presented. The patient was a 44-year-old man who had suffered from intermittent epigastralgia for about 2 years. Abdominal computed tomography demonstrated a low density mass with internal calcification over the left lobe of the liver. Celiac angiography showed encasement of the hepatic propia and occlusion of the left hepatic artery. Abnormal tortuous vascular structures were found at the hepatic hilar region. The patient underwent surgical intervention under the impression of left liver tumor. Microscopically, the resected liver tissue specimen revealed tuberculosis.

Adult↗

PubMed2001

Developmental alcohol and circadian clock function.

Studies in rats found that alcohol exposure during the early postnatal period, particularly during the brain-growth-spurt period, can result in cell loss in various brain regions and persistent behavioral impairments. Some investigators have speculated that the body's internal clock, which is located in the suprachiasmatic nuclei (SCN) in the brain, may also be affected by developmental alcohol exposure. For example, alcohol-induced damage to the SCN cells and their function could result in disturbances of the circadian timekeeping function, and these disturbances might contribute to the behavioral impairments and affective disorders observed in people prenatally exposed to alcohol. Preliminary findings of studies conducted in rats suggest that developmental alcohol exposure may indeed interfere with circadian clock function as evidenced by a shortened circadian sleep-wake cycle and changes in the release of certain brain chemicals (i.e., neuropeptides) by SCN cells.

Animals↗

PubMed2001

Ambulance utilization in metropolitan and rural areas in Taiwan.

BACKGROUND AND PURPOSE: Emergency medical services (EMS) have expanded rapidly in the Asian developing countries recently. However, the patterns of ambulance utilization in the rural and urban areas of these countries have not been thoroughly described. This study investigated the patterns of ambulance utilization in two urban areas and the larger rural area of Taiwan formerly designated Taiwan Province. METHODS: We studied a total of 304,368 ambulance missions during 1997 in Taiwan. We analyzed the differences in the characteristics of emergency calls and the interventions performed on the scene in two urban areas, Taipei City and Kaohsiung City, and in the rural area formerly designated Taiwan Province. RESULTS: The call volume and percentage of non-transport calls were higher in the more developed of the two urban areas, Taipei City, than in Kaohsiung (p < 0.01). The incidence of calls with trauma-related causes was higher in both urban areas. However, the percentage of calls placed for trauma-related reasons was higher in the rural area (p < 0.01). More calls for acute medical illness were placed in Taipei City (p < 0.01) than in the rural area. The number of interventions performed by ambulance staff was higher in Taipei City and Kaohsiung City than in the rural area (p < 0.01). The availability of acute illness management was generally lower than needed in all areas. CONCLUSIONS: Call volume and the number of interventions performed were higher in the urban area, whereas the percentage of trauma-related calls was higher in the rural area. These findings suggest that EMS use patterns in Taiwan are transitioning towards a pattern characteristic of a more developed country. The differences in ambulance utilization patterns must be considered in plans to further develop EMS services in these areas.

Ambulances↗