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Biomedical subjects

Ming Chen

Publications and source records attributed to Ming Chen.

157 records · Page 9Linked to original sources
PubMed2002

Protection of potassium channel inhibitors against hypoxia/reoxygenation-induced death of cultured hippocampal neurons.

OBJECTIVE: To investigate the effects of potassium channel inhibitors on hypoxia/reoxygenation-induced death of cultured hippocampal neurons. METHODS: Cultured 8 d in vitro, hippocampal neurons were exposed to hypoxia (in mixture of 95% N2 and 5% CO2) for 6 h, and then reoxygenated till the 72nd hour. Different potassium channel inhibitors were applied to the culture solution separately after reoxygenation. Neuron death was analyzed with cell counting and MTT assay. RESULTS: Hypoxia/reoxygenation procedure induced a delayed death of cultured hippocampal neurons. Application of tetraethylammonium (TEA) offered concentration-dependent protection of the neurons against death. Selective high-conductance calcium-activated potassium channel (BK) inhibitor iberiotoxin (IbTX) showed significant neuron protection (P<0.001). However, A-type potassium channel inhibitor 4-aminopyridine presented no protection against neuron death (P>0.05). CONCLUSION: Following hypoxia/reoxygenation, enhanced activity of potassium channel, especially BK channel, may induce neuron death.

4-Aminopyridine↗
PubMed2002

[Effects of Seroxat on premature ejaculation: a clinical trial].

OBJECTIVES: To evaluate the effects of antidepressant Seroxat on premature ejaculation. METHODS: After having taken Seroxat 20 mg every noon for four weeks, the patients were asked to fill the investigating questionaire about the effects and side effects before and after the treatment. RESULTS: After the treatment, 43 cases in our study had increased their ejaculation latency time, enhanced the quality of their sexy lives and their wives', and had significant difference compared with pre-treatment(P < 0.001). They had good effects on improving premature ejaculation after taking Seroxat (11.26 +/- 5.79) days; and after having stopped taking seroxat for (20.94 +/- 8.04) days, the situation of premature ejaculation in 32 cases were as same as that of before. There were seven cases whose sexuality and oomph increased, and two cases whose sexuality were decreased. A few patients had constipation, dry in mouth, insomnia and itch in skin, after taking the drugs. CONCLUSIONS: Antidepressant Seroxat has rather good effects on premature ejaculation and should be used and studied further.

Adult↗
PubMed2002

[Prognostic factors of 60 nasal cavity carcinoma patients].

OBJECTIVE: To evaluate the treatment modalities and the prognostic factors of nasal cavity carcinoma. METHODS: A retrospective study was done on 60 nasal cavity carcinoma patients treated from 1985 to 1992. Thirty-four patients received radiotherapy alone and 26 patients received surgery plus radiotherapy. Kaplan-Meier method was used to evaluate the survival, Log-rank test to assess the difference between these two groups and Cox proportional hazard model by multivariate analysis. RESULTS: The overall 5- and 10-year survival rates were 55.9% and 36.9% respectively. The 5- and 10-year survival rates were 79.0% and 57.9% in patients with early lesions (stage I, II) and 44.1% and 26.0% in patients with advanced lesions (stage III, IV) (P = 0.005). There was no significant difference in the survival rate between radiotherapy alone and radiotherapy plus surgery (P = 0.33). Patients with squamous cell carcinoma had obviously poorer survival rate than patients with adenocarcinoma (P = 0.04). Patients with positive nodes had a lower survival rate compared with negative node patients (P = 0.09). CONCLUSION: Histological type and clinical stage, but not method of treatment or neck node metastasis, are the important prognostic factors.

Adolescent↗
PubMed2001

Developmental expression and perturbation of arabinogalactan-proteins during seed germination and seedling growth in tomato.

Arabinogalactan-proteins (AGPs) are a family of highly glycosylated hydroxyproline-rich glycoproteins present throughout the plant kingdom. A synthetic chemical reagent, (beta-D-Gal)3 Yariv reagent, specifically binds AGPs and can be used for histochemical staining, isolating and probing the function of AGPs. Here, the role of AGPs in tomato (Lycopersicon esculentum Mill. cv. UC82B) seed germination and seedling growth was examined by following expression of AGPs during these events and by treatment with (beta-D-Gal)3 Yariv to perturb AGP function. AGP expression changed during germination and seedling development both quantitatively and qualitatively as revealed by analysis of total AGP content, crossed electrophoresis patterns, RNA blots using LeAGP-1 probe, and western blots with LeAGP-1, JIM13, and MAC207 antibodies. (beta-D-Gal)3 Yariv treatment of seeds and developing seedlings did not affect percent seed germination, but markedly inhibited seedling growth in roots and to a lesser degree in shoots. Root growth inhibition encompassed reductions in overall root length, epidermal root cell elongation, root cell numbers and root hair formation. This growth inhibition was reversible following removal of (beta-D-Gal)3 Yariv. In a related experiment, water uptake by tomato seedlings was greatly inhibited by (beta-D-Gal)3 Yariv treatment. Based on these experiments, AGPs are clearly associated with tomato seedling development and likely to function in root growth, more specifically in cell elongation, cell proliferation, root hair formation and water uptake.

Journal Article↗
PubMed2001

Automatic segmentation of cardiac magnetic resonance images using knowledge base.

OBJECTIVE: To study the automated implementation of cardiac magnetic resonance image (MRI) segmentation. METHODS: By training the feature parameters of the images and establishing a knowledge base, an efficient method for extracting and using prior knowledge was proposed. RESULTS and CONCLUSION: Through extracting and using prior knowledge of cardiac MRI, automation of cardiac MRI segmentation can be well accomplished.

Journal Article↗
PubMed2000

Revisiting Alzheimer's Disease from a New Perspective: Can "Risk Factors" Play a Key Role?

Alzheimer's disease (AD) has been intensively studied for decades, but why has its common pathological cause remained so enigmatic? Our studies have suggested that plaques and tangles occur spontaneously during aging as a result of a natural decline of energy metabolism and Ca2+ signaling, but not necessarily due to conventional pathogens. This view would lead to an unexpected outcome; that is, natural aging plays a more important role in neurodegeneration than is currently recognized. Does this model over-simplify the disease origin? We know that AD-type neurodegeneration typically occurs at the end stages of life when not only do plaques and tangles appear, but also many other bodily changes as well (bone loss and skin wrinkling, etc). Neurodegeneration differs from the latter changes mainly by "social" consequences, not by "physiological" origin. If neurodegeneration is a natural event, then why do only some people, but not others, develop AD? Obviously, additional factors are required for neurodegeneration to develop into AD. By comparing current models and ruling out other possibilities, we think that several known "risk factors" most likely play a critical role in the late-onset sporadic AD. These risk factors can exert their effects either by providing the conditions for ailing neurons to die (extended longevity and sedentary lifestyle), or by enhancing the individual's "vulnerability" to natural neurodegeneration (low synapse reserve). In this context, late-onset sporadic AD would be similar to many other age-related conditions where perhaps no single pathogen can be held exclusively responsible for most cases; rather, many risk factors are important to allow the initial defect to turn into clinical diseases. Accordingly, these factors should be the primary targets for AD prevention. Yet, some other AD cases, especially the early-onset ones, may be complicated by the concomitant involvement of other diseases in the brain.

Journal Article↗
PubMedDate not supplied

Comparison of the difference in histopathology and cell cycle kinetics among the postmenopausal endometrium treated with different progestins in sequential-combined hormone replacement therapy.

OBJECTIVE: To investigate the difference in histopathology and cell cycle kinetics in the menopausal endometrium treated with sequential-combined hormone replacement therapy (HRT) using different types and doses of progestins. DESIGN: A randomized, double-blind, 1-year study was conducted. In a menopause clinic of a university hospital, 241 postmenopausal women using HRT were included for the study of histopathology and cell cycle analysis. Conjugated equine estrogens, 0.625mg/day, were administered for 25 days (days 1-25) of each month, and the following were also administered for 14 days (days 12-25): in group A ( n= 102), medroxyprogesterone acetate (MPA), 5 mg/day; in group B ( n= 66), MPA, 10mg/day; and in group C ( n= 73), dydrogesterone, 20mg/day. Endometrial sampling was performed after at least 10 months of treatment. Fifty-two premenopausal women were also enrolled for the comparative studies (group Y). The S-G2-M fractions in the cell cycle were used as the marker of proliferation. RESULTS: Most menopausal endometria were normal regardless of the regimens of HRT. Endometrial hyperplasia was only found in two cases (both in group A). The S-G2-M fractions of the endometrial cells in all three menopausal groups showed no statistically significant difference. It appeared that S-G2-M fractions increased from normal postmenopausal to normal premenopausal endometria to postmenopausal hyperplasia to premenopausal hyperplasia. The S-G2-M fractions of the normal menopausal endometrial cells were lower than those of the premenopausal controls either in normal or in hyperplastic categories. CONCLUSIONS: Our study showed that there is no difference between the effect of MPA and dydrogesterone used in sequential-combined HRT based on the cycle kinetics of the menopausal endometrium.

Aged↗
PubMedDate not supplied

Prenatal diagnosis of a fetus affected with Down syndrome and deletion 1p36 syndrome by fluorescence in situ hybridization and spectral karyotyping.

OBJECTIVE: A fetus having partial trisomy of the distal part of chromosome 21q due to a de novo translocation is reported here. METHOD: A 29-year-old woman received amniocentesis at 18 weeks of gestation because of abnormal ultrasound findings including bilateral choroid plexus cysts, atrioventricular septal defects, rocker-bottom feet, and possible hydrocephalus. RESULTS: Cytogenetic analysis revealed 46,XY, add(1)(p36.3), in which an additional material of unknown origin was attached to one of the terminal short arms of chromosome 1. Parental blood studies showed normal karyotypes in both parents. Spectral karyotyping was then performed and the origin of the additional material locating at chromosome 1p was found to be from chromosome 21. Conventional fluorescence in situ hybridization analysis was also used and confirmed the spectral karyotyping findings by use of a chromosome 21 specific painting probe, a locus specific probe localized within bands 21q22.13-q22.2 and a 21q subtelomeric probe. A hidden Down syndrome caused by a de novo translocation in this fetus was therefore diagnosed and the karyotype was designated as 46,XY, der(1)t(1;21)(p36.3;q22.1).ish der(1)(WCP21+, LSI 21+, 1pTEL-, 21q TEL+) de novo. Clinical features of the 1p36 deletion syndrome are also reviewed and may contribute to some features of this fetus. Termination of pregnancy was performed at 20 weeks of gestation. CONCLUSION: To our knowledge, our case appears to be the first to have partial monosomy 1p and partial trisomy 21q caused by de novo translocation being diagnosed prenatally.

Adult↗
PubMedDate not supplied

Antenatal treatment of chylothorax and cystic hygroma with OK-432 in nonimmune hydrops fetalis.

OBJECTIVES: To present our experience of using OK-432 in treating fetal cystic hygroma and chylothorax complicated with nonimmune hydrops fetalis. METHODS: OK-432 (Picibanil) was injected into the fetal pleural cavity or fetal cystic hygroma. RESULTS: Patient 1: A 23-year-old, gravida 2, para 1, was found to have a recurrent fetal chylothorax at GA 29 weeks. Serial amnioreduction and thoracocentesis was performed at GA 31, 32, 33, and 34 weeks. Intrapleural OK-432 injection was performed twice at GA 33 and 34 weeks. Cyanosis and respiratory distress were noted immediately after birth (GA 34 weeks). The baby expired despite of aggressive neonatal resuscitation. Patient 2: A 26-year-old, gravida 2, para 1, was found to have a cystic hygroma of her fetus at GA 17 weeks. Karyotype of the cystic fluid and the amniocytes were 46, XY. Fetal ascites developed at GA 22 weeks. OK-432 injection into the tumour was performed at GA 23 weeks. Stabilization of the cystic hygroma was noted throughout the pregnancy (about 3.5 cm in diameter). Serial fetal paracentesis and/or amnioreduction were performed. Karyotype of the ascites was again 46, XY. Maternal dietary modification with medium chain triglyceride was also prescribed. Chylothorax developed and the baby was born by cesareans at GA 32 weeks. Resolution of pleural effusion, ascites, and regression of cystic hygroma were noted since the 2nd day after birth. The baby had survived beyond 4 months of age at submission. CONCLUSION: Combination of antenatal OK-432 injection, maternal dietary modification, serial thoracocentesis plus paracentesis, together with amnioreduction and tocolysis, appeared to contribute to the success of antenatal treatment. Fetal pulmonary expansion may determine the immediate neonatal survival.

Adult↗
PubMedDate not supplied

Aurones interfere with Leishmania major mitochondrial fumarate reductase.

A series of aurones was analyzed for the ability to inhibit respiratory functions of mitochondria of Leishmania parasites. The aim of this study was to find a rational explanation for the activity of certain aurones and auronols as novel antiprotozoal compounds of plant origin. In a cell-free assay mitochondrial fumarate reductase from L. donovani was inhibited in a concentration-dependent manner. The most active compounds were 4',6-dihydroxyaurone and 6-methoxyaurone which inhibited parasite enzyme activity at 25 nM by over ninety percent.

Animals↗
PubMedDate not supplied

Weathering of lead bullets and their environmental effects at outdoor shooting ranges.

Lead contamination at shooting range soils is of great environmental concern. This study focused on weathering of lead bullets and its effect on the environment at five outdoor shooting ranges in Florida, USA. Soil, plant, and water samples were collected from the ranges and analyzed for total Pb and/or toxicity characteristic leaching procedure (TCLP) Pb. Selected bullet and berm soil samples were mineralogically analyzed with X-ray diffraction and scanning electron microscopy. Hydrocerussite [Pb3(CO3)2(OH)2] was found in both the weathered crusts and berm soils in the shooting ranges with alkaline soil pH. For those shooting ranges with acidic soil pH, hydrocerussite, cerussite (PbCO3), and small amount of massicot (PbO) were predominantly present in the weathered crusts, but no lead carbonate mineral was found in the soils. However, hydroxypyromorphite [(Pb10(PO4)6(OH)2] was formed in a P-rich acidic soil, indicating that hydroxypyromorphite can be a stable mineral in P-rich shooting range soil. Total Pb and TCLP Pb in the soils from all five shooting ranges were significantly elevated with the highest total Pb concentration of 1.27 to 4.84% (w/w) in berm soils. Lead concentrations in most sampled soils exceeded the USEPA's critical level of 400 mg Pb kg(-1) soil. Lead was not detected in subsurface soils in most ranges except for one, where elevated Pb up to 522 mg kg(-1) was observed in the subsurface, possibly due to enhanced solubilization of organic Pb complexes at alkaline soil pH. Elevated total Pb concentrations in bermudagrass [Cynodon dactylon (L.) Pers.] (up to 806 mg kg(-1) in the aboveground parts) and in surface water (up to 289 microg L(-1)) were observed in some ranges. Ranges with high P content or high cation exchange capacity showed lower Pb mobility. Our research clearly demonstrates the importance of properly managing shooting ranges to minimize adverse effects of Pb on the environment.

Cynodon↗