Biomedical subjects

J L Wang

Publications and source records attributed to J L Wang.

At least 55 records · Page 3Linked to original sources

PubMed2001

Female sensitivity to diet and irradiation treatments underlies sex-mortality differentials in the Mediterranean fruit fly.

Large-scale experiments on medflies that were subjected to sterilizing doses of ionizing radiation (plus intact controls) and maintained on either sugar-only or full, protein-enriched diets revealed that, whereas the mortality trajectories of both intact and irradiated male cohorts maintained on both diets are similar, the mortality patterns of females are highly variable. Mean mortality rates at 35 days in male cohorts ranged from 0.2 to 0.3 but in female cohorts ranged from 0.09 to 0.35, depending on treatment. The study reports three main influences: (a) qualitative differences exist in the sex-mortality response of medflies subjected to dietary manipulations and irradiation; (b) the female mortality response is linked to increased vulnerability due to the nutritional demands of reproduction; and (c) female sensitivity to environmental changes underlies the dynamics of the sex-mortality differential.

Animals↗

PubMed2001

Intraocular lens power calculation after laser in situ keratomileusis for myopia and hyperopia: a standardized approach.

PURPOSE: (1) To determine the effect of myopic and hyperopic laser in situ keratomileusis (LASIK) on calculation of intraocular lens (IOL) power. (2) To determine a standard way to approach the IOL power determination after LASIK, and (3) To compare different suggested methods. METHODS: Biometric analysis and theoretical calculation of IOL powers for eyes undergoing LASIK for myopia and hyperopia were performed. RESULTS: Manual keratometry after LASIK for myopia resulted in underestimation of IOL power. Manual keratometry after hyperopic LASIK resulted in overestimation of IOL power. The amount of error was directly related to the amount of correction by LASIK. CONCLUSION: The pre-LASIK refraction can be used theoretically to determine an accurate IOL power.

Cataract Extraction↗

PubMed2001

Genetic deletion of COX-2 prevents increased renin expression in response to ACE inhibition.

Cyclooxygenase-2 (COX-2) is expressed in macula densa (MD) and surrounding cortical thick ascending limb of the loop of Henle (cTALH) and is involved in regulation of renin production. We and others have previously found that selective COX-2 inhibitors can inhibit renal renin production (Cheng HF, Wang JL, Zhang MZ, Miyazaki Y, Ichikawa I, McKanna JA, and Harris RC. J Clin Invest 103: 953-961, 1999; Harding P, Sigmon DH, Alfie ME, Huang PL, Fishman MC, Beierwaltes WH, and Carretero OA. Hypertension 29: 297-302, 1997; Traynor TR, Smart A, Briggs JP, and Schnermann J. Am J Physiol Renal Physiol 277: F706-F710, 1999; Wang JL, Cheng HF, and Harris RC. Hypertension 34: 96-101, 1999). In the present studies, we utilized mice with genetic deletions of the COX-2 gene in order to investigate further the potential role of COX-2 in mediation of the renin-angiotensin system (RAS). Age-matched wild-type (+/+), heterozygotes (+/-), and homozygous null mice (-/-) were administered the angiotensin-converting enzyme inhibitor (ACEI), captopril, for 7 days. ACEI failed to significantly increase plasma renin activity, renal renin mRNA expression, and renal renin activity in (-/-) mice. ACEI increased the number of cells expressing immunoreactive renin in the (+/+) mice both by inducing more juxtaglomerular cells to express immunoreactive renin and by recruiting additional renin-expressing cells in the more proximal afferent arteriole. In contrast, there was minimal recruitment of renin-expressing cells in the more proximal afferent arteriole of the -/- mice. In summary, these results indicate that ACEI-mediated increases in renal renin production were defective in COX-2 knockout (K/O) mice and provide further indication that MD COX-2 is an important mediator of the renin-angiotensin system.

Angiotensin-Converting Enzyme Inhibitors↗

PubMed2001

Mechanism of bradykinin-induced Ca(2+) mobilization in MG63 human osteosarcoma cells.

BACKGROUND: The effect of bradykinin on intracellular free Ca(2+) levels ([Ca(2+)](i)) in MG63 human osteosarcoma cells was explored using fura-2 as a Ca(2+) dye. METHODS/RESULTS: Bradykinin (0.1 nM-1 microM) increased [Ca(2+)](i) in a concentration-dependent manner with an EC(50) value of 0.5 nM. The [Ca(2+)](i) signal comprised an initial peak and a fast decay which returned to baseline in 2 min. Extracellular Ca(2+) removal inhibited the peak [Ca(2+)](i )signals by 35 +/- 3%. Bradykinin (1 nM) failed to increase [Ca(2+)](i) in the absence of extracellular Ca(2+ )after cells were pretreated with thapsigargin (an endoplasmic reticulum Ca(2+) pump inhibitor; 1 microM). Bradykinin (1 nM)-induced intracellular Ca(2+) release was nearly abolished by inhibiting phospholipase C with 2 microM 1-(6-((17 beta-3-methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl)-1H-pyrrole-2,5-dione (U73122). The [Ca(2+)](i )increase induced by 1 nM bradykinin in Ca(2+)- free medium was abolished by 1 nM HOE 140 (a B2 bradykinin receptor antagonist) but was not altered by 100 nM Des-Arg-HOE 140 (a B1 bradykinin receptor antagonist). Pretreatment with 1 pM pertussis toxin for 5 h in Ca(2+) medium inhibited 30 +/- 3% of 1 nM bradykinin-induced peak [Ca(2+)](i) increase. CONCLUSIONS: Together, this study shows that bradykinin induced [Ca(2+)](i) increases in a concentration-dependent manner, by stimulating B2 bradykinin receptors leading to mobilization of Ca(2+) from the thapsigargin-sensitive stores in a manner dependent on inositol-1,4,5-trisphosphate, and also by inducing extracellular Ca(2+) influx. The bradykinin response was partly coupled to a pertussis toxin-sensitive G protein pathway.

Biological Transport↗

PubMed2001

Alternative medicine use by individuals with major depression.

OBJECTIVE: To describe the use of alternative medicine (AM) by persons with major depression and to examine the factors associated with AM use among these individuals. METHODS: We used data from the 1994-1995 and 1996-1997 National Population Health Surveys. We selected subjects who had major depression according to the Composite International Diagnostic Interview Short Form for Major Depression (CIDI-SFMD). The prevalence of AM and conventional health service use by the subjects was calculated for each survey and was stratified by province. We employed logistic regression to examine the factors associated with AM use. RESULTS: There was a temporal trend toward increasing use of AM among persons with major depression. The prevalence of AM use among subjects with major depression was 7.8% in 1994-1995 and 12.9% in 1996-1997. Female sex, having more than 12 years' education, and having 1 or more long-term medical conditions were associated with an increased likelihood of using AM. The sex difference in AM use depended on subjects' age in 1996-1997. CONCLUSION: General practitioners, mental health specialists, and AM providers should be aware of their patients' use of both conventional medical services and AM because there may be interactions between conventional and alternative treatments. Communication and, if possible, cooperation may lead to improved outcomes in the management of depressive disorders.

Adolescent↗

PubMed2001

Effects of the antianginal drug fendiline on Ca2+ movement in hepatoma cells.

This study investigated the effect of the anti-anginal drug, fendiline, on intracellular free Ca2+ levels ([Ca2+]i) in HA/ 22 human hepatoma cells by using fura-2 as a fluorescent Ca2+ dye. Fendiline (1-100 microM) increased [Ca2+]i with an EC50 of 25 microM. Removal of extracellular Ca2+ reduced the [Ca2+]i signals by 51 +/- 5%. Fendiline (10 microM)-induced Ca2+ release was abolished by pretreatment with 1 microM thapsigargin (an endoplasmic reticulum Ca2+ pump inhibitor). Inhibition of phospholipase C with 2 microM 1-(6-((17beta-3-methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl)-1H-pyrrole-2,5-dione (U73122) did not alter 10 microM fendiline-induced Ca2+ release. Several other calmodulin antagonists, such as phenoxybenzamine (100-200 microM), trifluoperazine (5-50 microM), and fluphenazine-N-chloroethane (2-100 microM), had no effect on [Ca2+]i. Together, it was found that fendiline increased [Ca2+]i in human hepatoma cells by discharging Ca2+ from the endoplasmic reticulum in an inositol 1,4,5-trisphosphate-independent manner and by inducing Ca2+ entry. This effect of fendiline does not appear to be via antagonism of calmodulin.

Calcium↗

PubMed2001

[Studies on asymmetric synthesis of R-phenylethanolamine by whole cells of Arachnia sp. P163].

Effects of various factors on asymmetric synthesis of R-phenylaminoethanol from aminoacetophenone by the whole cells of Arachnia sp. P163 producing alcohol dehydrogenase for phenylethanol amine was investigated. It found that, although the reduction was inhibited by the substrate and the product, but it has the very high stereoselectivity. The reduction was normaly carried out with 2% glucose for reproduction of coenzyme in the reaction system without oxygen. The conversion yield and ee value of the product achieved 65% and 100%, respectively.

2-Hydroxyphenethylamine↗

PubMed2001

Surface keratopathy after penetrating keratoplasty.

PURPOSE: To determine the type and prevalence of epithelial abnormalities in the intermediate postoperative period after penetrating keratoplasty and to define the donor and recipient variables that influence the status of the graft epithelium. DESIGN: Prospective cohort study. METHODS: We prospectively followed the clinical course of 80 patients after penetrating keratoplasty. We monitored the status of the corneal epithelium for 3 months after surgery using slit-lamp biomicroscopy and fluorescein staining of the epithelium. Donor characteristics, recipient preoperative and postoperative variables, and postoperative medications were recorded. Epithelial abnormalities were analyzed against these variables by using univariate and combined statistical models to determine the impact of each variable on postoperative epithelial pathology. Main outcome measures included punctate keratopathy, macro-epithelial defects, hurricane keratopathy, rim defects, and filamentary keratopathy. RESULTS: Sixty-three percent of all patient visits demonstrated punctate epithelial keratopathy (PEK). Hurricane keratopathy (51%) and filamentary keratopathy (14%) constituted the next most commonly observed abnormalities. Older recipient age and the use of topical antibiotics were associated with a higher prevalence of punctate epithelial keratopathy. The odds ratio (OR) for a 1-year increase in age is 1.0276 (95% CI, 1.1013-1.0442), and the OR for using topical antibiotics is 6.9028 (95% CI, 3.1506-15.1239). Use of topical ofloxacin and increased time after surgery were associated with lower prevalence of punctate keratopathy; ORs were 0.9806 (95% CI, 0.9736-0.9876) and 0.3662 (95% CI, 0.1688-0.7943), respectively. Decreased corneal sensation and the presence of anterior blepharitis preoperatively were associated with an increase in hurricane keratopathy; ORs were 8.8265 (CI, 2.3837-32.6835) and 3.2815 (CI, 1.7388-6.1931), respectively. Total storage time for the donor material was also associated with an increased prevalence of hurricane keratopathy (OR, 1.0316; CI, 1.0052-1.0220). Patients with rim defects and macro-epithelial defects were more likely to have antibiotic and topical lubrication prescribed. No specific variable was found to have a significant association with filamentary keratopathy, except possibly for death-to-preservation time, which had a P value of .0587. CONCLUSIONS: Surface keratopathy is one of the most common complications of keratoplasty. Our study demonstrates that older age, preoperative lid disease, and decreased preoperative corneal sensation appear to increase the probability of clinically significant epithelial surface abnormalities after keratoplasty. Recognition of these risk factors in advance of surgery will alert the surgeon to the need for appropriate management.

Adolescent↗

PubMed2001

[Effects of combined transdermal acupoint electric stimulation and isoflurane anesthesia on isoflurane-induced hypotension and tissue oxygen metabolism in patients undergoing craniotomy].

OBJECTIVE: To observe the effects of combined transdermal acupoint electric stimulation and isoflurane anesthesia on isoflurane-induced hypotension and tissue oxygen metabolism in patients undergoing craniotomy. METHODS: Forty-two patients with brain tumor of ASA physical status I or II and scheduled for elective surgery were randomly divided into two groups. The craniotomy was undergoing in Group A with isoflurane anesthesia, while in Group B, with combined transdermal acupoint electric stimulation (TAES) and isoflurane anesthesia. Isoflurane induced hypotension was performed in both groups by augmenting the concentration of isoflurane to lower the mean arterial pressure than before anesthesia for 30%-40% and maintain for 30-45 mins. The tissue oxygen metabolism, blood gas and arterial lactic acid level before, during and after hypotension were monitored by Swan-Ganz floating catheterization. RESULTS: As compared with before hypotension, the pulmonary arterial and mixed with venous blood oxygen saturation lowered and oxygen supply lowered, and oxygen uptake increased significantly in both groups (P < 0.05), but the extent of changes in oxygen metabolic criteria in Group B were all lesser than those in Group A (P < 0.05). CONCLUSION: Combined acupoint electric stimulation and general anesthesia could maintain the tissue oxygen supply and demand balance better in the isofluraneinduced hypotension process.

Acupuncture Points↗

PubMed2001

[Cochinchinenin--a new chalcone dimer from the Chinese dragon blood].

AIM: To study the active constituents of Dracaena cochinchinensis (Lour.) S.C. Chen. in the commercial dragon blood. METHODS: Various column chromatographies with Sephadex L-20 gel, MCI gel and silica gel were employed for the isolation and purification. The structures of compounds were elucidated by spectral analysis. RESULTS: Nine chalcones were isolated from the commercial dragon's blood which was made of D. cochinchinensis (Lour.) S.C. Chen.. By means of spectral data, they were identified as 1-[5-(2,4,4'-trihydroxydihydrochalconyl)]-1- (p-hydroxyphenyl)-3-(2-methoxy-4-hydroxy-phenyl)-propane (1), 2'-methoxysocotrin-5'-ol (2), socotrin-4'-ol (3), 2-methoxy-4, 4'-dihydroxydihydrochalcone (4), 2, 4, 4'-trihydroxy-dihydrochalcone (5), 2, 4, 4'-trihydroxy-6-methoxydihydrochalcone (6), 2', 4', 4-trihydroxychalcone (7), 2-methoxy-4, 4'-dihydroxychalcone (8) and 2'-methoxy-4', 4-dihydroxychalcone (9). CONCLUSION: Compound 1 is a new chalcone dimer and named as cochinchinenin. Compounds 2-9 were isolated from D. cochinchinensis (Lour.) S.C. Chen. for the first time.

Chalcone↗

PubMed2001

[The experimental study of the delayed replantation after cryopreservation of mature tooth in dogs].

OBJECTIVE: To study the conditions of healing of mature tooth in dogs after long cryopreservation followed by replantation. METHODS: The tooth was extracted after filling the root canals and then preserved for one week and three months respectively by Schwartz's method of cryopreservation of periodontal membrane. The specimens were took out eight weeks after replantation. It was demineralized in a 5% solution of formic acid,and then sectioned perpendicular to the long axes of tooth at a thickness of 5microm. The tooth were sectioned in step-serial sections at 500 microm intervals. The sections were stained with hematoxylin-eosin and followed by evaluation according to Andreasen. RESULTS: The percentage of healing of periodontal membrane (PHPM) of the group of cryopreservation for one week was 64.53%. It was lower than the PHPM of the group of immediate replantation (85%), but the difference demonstrated no significance (P>0.05). The PHPM of the group of cryopreservation for three months was 50.3%. It was lower than the PHPM of the group of immediate replantation significantly (P<0.05). CONCLUSION: The human's periodontal membrane may be cryopreserved longly and heals after the replantation of tooth as the human's tissues of corneas, skin, islets, et al may be done. The alveolar cavities to be newly made affect the healing of periodontal membrane in some degree.

English Abstract↗

PubMed2000

Histamine-Induced increases in intracellular free Ca2+ levels in hepatoma cells.

The effect of histamine on intracellular free Ca2+ levels ([Ca2+]i) in HA22/VGH human hepatoma cells were evaluated using fura-2 as a fluorescent Ca2+ dye. Histamine (0.2-5 microM) increased [Ca2+]i in a concentration-dependent manner with an EC50 value of about 1 microM. The [Ca2+]i response comprised an initial rise, a slow decay, and a sustained phase. Extracellular Ca2+ removal inhibited 50% of the [Ca2+]i signal. In Ca2+-free medium, after cells were treated with 1 microM thapsigargin (an endoplasmic reticulum Ca2+ pump inhibitor), 5 microM histamine failed to increase [Ca2+]i. After pretreatment with 5 microM histamine in Ca2+-free medium for 4 min, addition of 3 mM Ca2+ induced a [Ca2+]i increase of a magnitude 7-fold greater than control. Histamine (5 microM)-induced intracellular Ca2+ release was abolished by inhibiting phospholipase C with 2 microM 1-(6-((17beta-3-methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl)-1H-pyrrole-2,5-dione (U73122), and by 5 microM pyrilamine but was not altered by 50 microM cimetidine. Together, this study shows that histamine induced [Ca2+]i increases in human hepatoma cells by stimulating H1, but not H2, histamine receptors. The [Ca2+]i signal was caused by Ca2+ release from thapsigargin-sensitive endoplasmic reticulum in an inositol 1,4,5-trisphosphate-dependent manner, accompanied by Ca2+ entry.

Biological Transport↗

PubMed2000

Synthesis of 60- and 72 kDa heat shock proteins in early porcine embryogenesis.

Proteins of selected embryonic stages were metabolically labeled with [(35)S]-methionine and analyzed by two-dimensional SDS-polyacrylamide gel electrophoresis (2-D PAGE) to study protein expression from 4- to 8-cell to blastocyst stage of porcine embryos. Two proteins with molecular weights of 60 and 72kDa were de novo synthesized during the 4- to 8-cell stage were the earliest that were detected. They were identified as HSP60 and HSP72 according to their locations on 2-D autoradiography and the immunoblotting result of anti-HSP 60 and HSP 72 antibodies of 1-cell stage of porcine embryos. In protein translation in early pig embryogenesis the timing of their synthesis suggests that HSP60 and HSP72 play significant roles as chaperones.

Animals↗

PubMed2000

Cryogen free automated gas chromatography for the measurement of ambient volatile organic compounds.

An automated gas chromatographic system was constructed for measuring ambient volatile organic compounds (VOCs). Preconcentration of the VOCs was performed by using two separated sorbent traps of different combinations with each designated for either low or high boiling VOCs. Both traps and their associated valve systems were integrated as a complete system sharing a common sample inlet. Precise temperature controls for desorption relied on the use of a process controller with proportional-integral-derivative algorithm to throttle the current supply. No additional cryo-focusing stage prior to the column was needed owing to the flash heating capability for desorption. Other than the cryogen free preconcentration and focusing, the separation of VOCs of large volatility difference was also performed without cryogen. The system employed an Al2O3/KCl porous-layer open tubular column for separating C3-C7 compounds; and a DB-1 column for C6-C12. This automated GC system has been deployed in a Taiwan Environmental Protection Agency urban air quality monitoring station of Taiwan for continuous measuring C3-C7 ozone precursors. Excellent correlation between the car exhaust type of compounds measured by our GC system and carbon monoxide measured by a non-dispersive infrared spectrometer was observed, suggesting the automated GC system was robust and reliable.

Automation↗

PubMed2000

Breast-cancer diagnosis with nipple fluid bFGF.

Early diagnosis of breast cancer is the key to extending survival of breast-cancer patients. We found that the concentrations of nipple fluid bFGF (basic fibroblast growth factor) was significantly increased in breast-cancer patients compared with concentrations in controls (1717 ng/L [SD 706] vs 19 ng/L [19]; Student's t test p=0.027). Measurement of bFGF in nipple fluid could be a useful diagnostic tool for breast cancer, and deserves further study.

Biomarkers, Tumor↗

PubMed2000

The human myoepithelial cell displays a multifaceted anti-angiogenic phenotype.

Human myoepithelial cells which surround ducts and acini of certain organs such as the breast form a natural border separating epithelial cells from stromal angiogenesis. Myoepithelial cell lines (HMS-1-6), derived from diverse benign myoepithelial tumors, all constitutively express high levels of active angiogenic inhibitors which include TIMP-1, thrombospondin-1 and soluble bFGF receptors but very low levels of angiogenic factors. These myoepithelial cell lines inhibit endothelial cell chemotaxis and proliferation. These myoepithelial cell lines sense hypoxia, respond to low O2 tension by increased HIF-1 alpha but with only a minimal increase in VEGF and iNOS steady state mRNA levels. Their corresponding xenografts (HMS-X-6X) grow very slowly compared to their non-myoepithelial carcinomatous counterparts and accumulate an abundant extracellular matrix devoid of angiogenesis but containing bound angiogenic inhibitors. These myoepithelial xenografts exhibit only minimal hypoxia but extensive necrosis in comparison to their non-myoepithelial xenograft counterparts. These former xenografts inhibit local and systemic tumor-induced angiogenesis and metastasis presumably from their matrix-bound and released circulating angiogenic inhibitors. These observations collectively support the hypothesis that the human myoepithelial cell (even when transformed) is a natural suppressor of angiogenesis. Oncogene (2000) 19, 3449 - 3459

Animals↗

PubMed2000

The effects of pedicle screw adjustments on neural spaces in burst fracture surgery.

STUDY DESIGN: An in vitro biomechanical study of experimental burst fractures and a pedicle screw device. OBJECTIVES: To investigate the effects that adjustments of a pedicle screw device have on the neural spaces of the burst fracture. SUMMARY OF BACKGROUND DATA: Decompression of the neural spaces is important for the recovery of neural function after a burst fracture. No studies, experimental or clinical, are available that have attempted to relate the pedicle screw device adjustments to the decompression of the neural spaces. METHODS: Burst fractures were produced at L1 vertebra in nine human lumbar spine specimens. Pedicle screw devices were attached to T12 and L2. Eight device adjustments, consisting of pure translations (distraction or compression), pure extension, and combinations of translation and extension were applied. The dimensional changes in the canal and the superior and inferior intervertebral foramens were measured. Functions of restoration and improvement were determined for the adjustments to evaluate the effects of each adjustment and to determine the optimal adjustment. Analysis of variance was used to find statistically significant differences, with significance set at P values less than 0.05. RESULTS: Significant differences were observed in the results of the eight adjustments. The most effective adjustments were the combination of 5-mm distraction with 6 degrees extension or 10-mm distraction alone. The worst adjustment was 5 mm of compression. CONCLUSIONS: Restoring compromised neural spaces in a patient with burst fracture is necessary. The choice of a device adjustment was found to be an important factor in the decompression of the neural spaces after the burst fracture. Combined distraction with extension and distraction alone were found to decompress the canal andintervertebral foramens maximally in a burst fracture.

Adult↗

PubMed2000

The role of bone graft force in stabilizing the multilevel anterior cervical spine plate system.

STUDY DESIGN: The role of bone graft force in stabilizing an instrumented cervical spine was evaluated for one-level and three-level corpectomy models using in vitro experiments. OBJECTIVES: To investigate the role of bone graft force in enhancing stability of anterior cervical plate, and to study effects of fatigue loading. SUMMARY OF BACKGROUND DATA: The anterior cervical plate system is used widely in stabilizing the cervical spine after spinal corpectomy and grafting. Many factors such as applied screw torque, screw pullout force, plate strength, plate geometry, and type of bone graft have been studied. However, the role of bone graft in stabilizing the anterior plate system has not been explored. METHODS: Two models (one-level and three-level) incorporating corpectomy, strut graft, and anterior plate were constructed from eight human spine specimens (C2-T1). The flexibility of an intact specimen and two constructs with graft forces of 0 N and 100 N was determined. A flexibility test, simulating physiologic loads, consisted of pure moments of flexion, extension, lateral bending, and axial torques up to 1 Nm. For each moment, range of motion and neutral zone were determined. The stability potential index was defined as the decrease in motion caused by instrumentation, as compared with intact motion. A larger stability potential index indicates a more stable spinal construct. Repeated measures analysis of variance was used to determine the significant changes. RESULTS: In both models, bone graft force increased during extension, decreased during flexion, and showed minor changes during axial torsion and lateral bending. Higher bone graft force increased stability potential index-neutral zone and stability potential index-range of motion in the three-level model in all directions, but only in flexion-extension in the one-level model. Fatigue loading decreased bone graft force to a greater extent in the three-level model. CONCLUSIONS: In the corpectomy-graft-anterior-plate model, graft force decreased in flexion and increased in extension. Higher graft force increased and fatigue decreased stability of the spinal construct in the three-level model.

Adolescent↗