Biomedical subjects

W C Lee

Publications and source records attributed to W C Lee.

At least 55 records · Page 3Linked to original sources

PubMed2001

Effects of the testing situation on item responding: cause for concern.

The effects of faking on personality test scores have been studied previously by comparing (a) experimental groups instructed to fake or answer honestly, (b) subgroups created from a single sample of applicants or nonapplicants by using impression management scores, and (c) job applicants and nonapplicants. In this investigation, the latter 2 methods were used to study the effects of faking on the functioning of the items and scales of the Sixteen Personality Factor Questionnaire. A variety of item response theory methods were used to detect differential item/test functioning, interpreted as evidence of faking. The presence of differential item/test functioning across testing situations suggests that faking adversely affects the construct validity of personality scales and that it is problematic to study faking by comparing groups defined by impression management scores.

Adult↗

PubMed2001

Lamivudine is effective for the treatment of reactivation of hepatitis B virus and fulminant hepatic failure in renal transplant recipients.

Lamivudine is a potent inhibitor of hepatitis B virus (HBV) replication. The aim of this study is to elucidate the effectiveness of lamivudine for the treatment of HBV reactivation with or without fulminant hepatic failure in renal transplant recipients. Forty-two renal transplant recipients (30 men, 12 women) were enrolled onto this study. Eight patients presented with HBV reactivation without fulminant hepatic failure and were administered lamivudine (group I), 5 patients presented with HBV and hepatic failure and were administered lamivudine (group II), 5 patients presented with HBV and hepatic failure but were not administered lamivudine (group III), and 24 patients were asymptomatic HBV carriers who were not administered lamivudine (group IV). Lamivudine was administered at a dose of 100 or 150 mg once daily. A greater prevalence of recent use of a combination of antilymphocyte immunoglobulin (ALG) and methylprednisolone (MP) occurred in patients with hepatic failure (groups II and III) than those without hepatic failure (30% versus 6.3%; P = 0.043). However, there was no significant difference in the incidence of MP use alone (20% versus 25%; P = 0.746). Mortality rates for groups I, II, and III were significantly different (12.5%, 40%, 100%; P = 0.008). One patient in group I died of sepsis without evidence of HBV DNA, even in the terminal event. In group II, 3 of 5 patients (60%) were rescued by lamivudine therapy. In group III, without lamivudine treatment, there was a 100% mortality rate despite intensive plasmapheresis. HBV DNA was not detectable after lamivudine treatment in 7 of 8 patients in group I and 3 of 5 patients in group II. Creatinine levels did not change significantly during lamivudine treatment. Hepatitis B surface antigen and hepatitis B e antigen seroconversion rates after lamivudine treatment were 7.7% and 37.5%, respectively. We conclude that ALG is a potent trigger of HBV-related fulminant hepatic failure in renal transplant recipients, whereas lamivudine is an effective and lifesaving treatment. Prompt use of lamivudine is recommended in renal transplant recipients with evidence of HBV reactivation to prevent catastrophic fulminant hepatic failure.

Adolescent↗

PubMed2001

Effective treatment of small murine hepatocellular carcinoma by dendritic cells.

Hepatocellular carcinoma (HCC) is a common malignancy with a poor prognosis. This investigation examined whether dendritic cell-based immunotherapy can treat murine HCC effectively. Bone marrow-derived dendritic cells were propagated from C57BL/10J mice in GM-CSF (4 ng/mL) and interleukin (IL)-4 (1,000 micro/mL). The dendritic cells were pulsed with a Hepa1-6 lysate overnight and employed to treat murine HCC. For in vivo study, HCC was created by inoculation of hepa1-6, 5 x 10(5) cells, in the flank of C57BL/10J mice. HCC were categorized into small (3 x 3-mm) and large (5 x 5-mm) tumors. These HCC were treated by dendritic cells intravenously, twice at weekly intervals. The results revealed that lymphocytes could be gathered around small HCC after administration of Hepa1-6 lysate-pulsed dendritic cells. Seven of 12 (58.3%) small HCC could be eradicated completely by dendritic cell-based immunotherapy, and 33.3% of the small tumors responded to immunotherapy partially which were held in a stable condition for 34.0 +/- 7.4 days before the tumors regrew. For large HCC, lymphocytes did not gather around the tumors, and the tumors cannot be eradicated effectively by dendritic cells. However, dendritic cell-based immunotherapy could slow down the growth rate of large tumors (116.2 +/- 91.4 mm(3) vs. 234.0 +/- 149.1 mm(3) of the control on day 7, P =.043; and 280.3 +/- 224.7 mm(3) vs. 870.0 +/- 418.9 mm(3) of the control on day 17, P <.001). Conclusively, dendritic cells pulsed with a Hepa1-6 lysate can be employed to treat small HCC in vivo effectively. However, the efficacy of dendritic cell-based immunotherapy decreases while tumors grow.

Animals↗

PubMed2001

Hemodynamic effects of a combination of prazosin and terlipressin in patients with viral cirrhosis.

OBJECTIVES: Terlipressin reduces portal pressure in cirrhotic patients mainly through intense splanchnic vasoconstriction that decrease portal venous inflow. Hepatic blood flow may also be reduced by terlipressin. Prazosin (an alpha1-adrenoceptor antagonist) has also been proposed to decrease portal pressure in cirrhotic patients possibly through a decrease in the intrahepatic vascular resistance. The current study was aimed to evaluate whether a combination of prazosin and terlipressin exerts more beneficial effects than terlipressin alone. METHODS: Patients were randomly assigned to receive either a placebo (n = 12) or an oral administration of prazosin 2 mg (n = 12). Thereafter, each patient received an intravenous injection of terlipressin 2 mg. Hemodynamic values were measured basally, 30 min after prazosin or placebo, and 30 min after terlipressin. RESULTS: Placebo administration did not affect any hemodynamic values. Terlipressin administration, on the other hand, resulted in expected changes on the hepatic venous pressure gradient, hepatic blood flow, and systemic hemodynamics. In contrast, prazosin significantly decreased hepatic venous pressure gradient with an increased hepatic blood flow and intrinsic hepatic clearance. After terlipressin administration, a further decrease in hepatic venous pressure gradient was observed with preservation of hepatic blood flow and intrinsic hepatic clearance. The magnitude of decrease in hepatic venous pressure gradient was more profound in patients receiving prazosin plus terlipressin than in those receiving terlipressin alone. However, the magnitude of changes in systemic hemodynamics was no different between the two groups of patients. CONCLUSIONS: The current study showed that a combination of prazosin and terlipressin resulted in a more profound reduction of hepatic venous pressure gradient with a preservation of hepatic blood flow and intrinsic hepatic clearance than did terlipressin alone. However, the combined therapy did not modify the systemic hemodynamic effects exerted by terlipressin.

Antihypertensive Agents↗

PubMed2001

Adaptive vasodilatory response after octreotide treatment.

Despite the suppression of glucagon release, an adaptive response aimed at maintaining vasodilatation after octreotide treatment may exist in portal hypertension. The present study was undertaken to evaluate the possible interaction between endothelium and non-endothelium-derived vasodilators after 1-wk octreotide administration in cirrhotic rats. Rats were allocated to receive either vehicle or octreotide (30 or 100 microg/kg every 12 h subcutaneously). Hemodynamic values, plasma glucagon levels, endothelium-related vasodilatory activities, and aortic endothelial nitric oxide synthase (eNOS) expression were determined after treatment. Octreotide administration decreased plasma glucagon and increased serum 6-keto-PGF(1 alpha) and NOx levels without affecting the hemodynamic values. In cirrhotic rats receiving octreotide, there was a blunt response to either L-NAME or indomethacin administration alone, but this blunt pressor response disappeared after simultaneous administration of the two drugs. Additionally, an increased aortic eNOS expression was observed in cirrhotic rats receiving 1-wk octreotide. It is concluded that 1-wk octreotide treatment did not correct the hemodynamic derangement in cirrhotic rats. The enhanced endothelium-related vasodilatory activity was noted after octreotide treatment that overcame the octreotide-induced hemodynamic effects in portal hypertension.

6-Ketoprostaglandin F1 alpha↗

PubMed2001

Foodborne illness outbreaks in Korea and Japan studied retrospectively.

The average prevalence of reported foodborne illness from 1981 to 1995 was 2.44 per 100,000 population in Korea, and 28.01 in Japan. The mean case fatality rate in Korea was 0.74% and in Japan, 0.03%. When both prevalence and case fatality rates in Korea and Japan were compared during the same period, the prevalence in Japan was much higher than that in Korea. However, the case fatality rate of patients in Korea was much higher than that in Japan. The distribution of monthly and seasonal patterns of foodborne illness outbreaks strongly indicate the outbreaks may be associated with climatic conditions, frequencies of national holidays, and vacation seasons. Comparison study indicates that the foodborne illness outbreaks in Korea most frequently involved homemade foods (47% of the total cases); in Japan, restaurants accounted for 31.3%. Foodborne illness cases of bacterial origin in Korea were 59.3% of the total and included Salmonella spp. (20.7%). Vibrio (17.4%), Staphylococcus (9.7%), pathogenic Escherichia coli (2.4%), and other species (9.1%); in Japan, 72.8% of the total cases and the majority of the bacterial foodborne illness was caused by Vibrio (32.3%), Staphylococcus (15.9%), Salmonella (14.2%), pathogenic E. coli (3.0%), and other species (7.2%). In conclusion, the outbreaks of foodborne illness in Korea and Japan may be mainly caused by improper food handling, and their occurrences may be differentiated according to food sources.

Disease Outbreaks↗

PubMed2001

Mirizzi's syndrome: experience from a multi-institutional review.

P.L. Mirizzi described in 1948 a partial or spastic obstruction of the common hepatic duct secondary to an impacted gallstone in the cystic duct or infundibulum of the gallbladder. The modern definition of Mirizzi's syndrome is thought to include four components: anatomic arrangement of the cystic duct at the gallbladder neck such that it runs parallel to the common hepatic duct; impaction of a stone in the cystic duct or neck of the gallbladder; mechanical obstruction of the common hepatic duct by the stone itself or by secondary inflammation; and intermittent or constant jaundice causing possible recurrent cholangitis and, if longstanding, secondary biliary cirrhosis. Intermittent symptomatology may make Mirizzi's syndrome difficult to diagnose preoperatively or intraoperatively. Bilio-biliary fistulas may or may not be present. Diagnosis and choice of operative repair may be best accomplished by open operative technique. Over a 24-year period two faculty members from Louisiana State University (LSU) Medical Center-Shreveport at Monroe and LSU Baton Rouge treated 4180 cases of cholelithiasis at six Louisiana university and private hospitals. Eleven cases of Mirizzi's syndrome were diagnosed on the basis of operative and preoperative notes with detailed description of size and extent of biliobiliary fistulas when they were present. These 11 cases were reviewed and followed from one to 20 years. Presentation, workup, operative findings, choice of operative repair, choice of operative approach, and complications were evaluated by retrospective chart review. Review of the pertinent literature for informative and comparative purposes was also completed. These 11 cases ranged from Csendes Type I to III. There were no Type IV cases. They were ultimately diagnosed and managed by classical open technique. Four laparoscopic procedures were converted to open technique following initial inspection. All four were converted to open as a result of inability to delineate structures in and adjacent to the triangle of Calot due to marked scarring in the subhepatic space. No iatrogenic injuries or major complications occurred. Mirizzi's syndrome occurs in fewer than 0.5 per cent of patients with cholelithiasis. Removal of stones with partial cholecystectomy and use of gallbladder or cystic duct remnant to oversew or repair Mirizzi fistulas should be considered. Roux-en-y hepaticojejunostomy becomes the procedure of choice when the vascularity or viability of the hepatic duct or tissues available for duct repair is questionable. Review of the literature reveals the increase in complications with laparoscopic versus open technique in Mirizzi's syndrome. Although very little direct evidence exists we believe that when this syndrome is diagnosed or strongly suspected open biliary operation is the procedure of choice because the increased potential for major complications with the use of laparoscopic technique far outweighs the potential slight increase in morbidity of an open procedure.

Bile Ducts↗

PubMed2001

Surgical management for chronic pancreatitis.

This study reviewed the results of surgery for chronic pancreatitis. We also attempted to identify any factors that may influence outcome. A 10-year retrospective chart review was carried out on all patients undergoing surgery for the diagnosis of chronic pancreatitis. Twenty-three patients were identified. Alcohol was the most common etiology, but other causes were identified. All but two patients had abnormal ductal anatomy on endoscopic retrograde cholangiopancreatography. A total of 23 patients underwent six different operations. There were five complications and no perioperative deaths. Only one patient had to be readmitted for pancreatitis during follow-up. The majority of patients reported some improvement with their pain. Patients who continued to use alcohol had the worst results in regard to weight gain and pain control. The results of our study are consistent with the current literature in regard to morbidity and mortality. Surgical treatment had minimal effect on endocrine and exocrine function. Weight loss was avoided in the majority of patients. Addition of biliary bypass to the Puestow procedure did not increase morbidity. Poorest results were obtained in patients who continued to use alcohol. A basic algorithm for management of this disease process is given.

Adolescent↗

PubMed2000

Molecular cloning and expression analysis of human glycogen synthase kinase-3 alpha promoter.

Human glycogen synthase kinase-3 alpha (GSK-3 alpha) is a serine/threonine kinase that phosphorylates a variety of cytoplasmic and nuclear proteins. It also phosphorylates components of the neuronal cytoskeleton including tau and neurofilament heavy chain. Hyperphosphorylated tau is found in neurofibrillary tangles, a hallmark of Alzheimer's disease and aberrant phosphorylation of neurofilament heavy chain is observed in motor neuron disease. Alterations in GSK-3 alpha activity may therefore contribute to the disease process in these disorders. As a first step to understand the transcriptional regulation of GSK-3 alpha, a 2-kb (p-1751/+243) DNA fragment upstream of the GSK-3 alpha initiation codon was obtained from a YAC clone and characterised. Using primer extension assays, a putative transcriptional start site was located to a G nucleotide 244 bp upstream of the ATG codon. Several transcription factor-binding sites were identified on the promoter region, but no TATA-like element was located close to the start site. Deletion mutants of the 2-kb DNA fragment were generated and fused to a promoterless chloramphenicol acetyltransferase (CAT) gene. Transfection study in a neuroblastoma cell line revealed the 1-kb (p-719/+243) fragment carried strong promoter activity, while the 2-kb construct that contains an Alu-like sequence was only 50% active.

Alu Elements↗

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

Association of heat shock protein 70 with semen quality in boars.

This study attempted to clarify the relationship between the levels of 70kDa heat shock protein (HSP70) and semen quality in boars. Semen samples from 29 (13 Duroc, 9 Landrace, and 7 Yorkshire) boars (mean age=25.2+/-2.2 months) were examined. Three to four ejaculates per boar, collected during cool and hot seasons, were evaluated in terms of the sperm concentration, sperm motility, percentage of normal and abnormal sperm, as well as percentage of sperm with proximal and distal plasma droplets. Significant seasonal and breed differences in semen quality were observed. Experimental results indicate that the semen quality of Landrace boars was better than those of Yorkshire and Duroc boars (P<0.05) and semen quality declined significantly during the hot season (P<0.05). One-dimensional SDS-PAGE analysis of spermatozoa proteins indicated that protein profiles did not significantly differ between seasons and among breeds. Both constitutive and stress-inducible form of HSP70 were detected in boar spermatozoa by Western blot analysis. The level of HSP70, which revealed no difference among breeds within a season, was significantly lower during the hot season in all the three breeds (P<0.05). Although there appeared to be low correlation coefficients between the level of HSP70 and semen quality traits, the semen quality tended to decline significantly in samples with a lower level of HSP70. Results in this study suggest that the levels of HSP70 in boar spermatozoa are significantly lower during the hot season and might be associated with semen quality.

Animals↗

PubMed2000

Structure and site-directed mutagenesis of a flavoprotein from Escherichia coli that reduces nitrocompounds: alteration of pyridine nucleotide binding by a single amino acid substitution.

The crystal structure of a major oxygen-insensitive nitroreductase (NfsA) from Escherichia coli has been solved by the molecular replacement method at 1.7-A resolution. This enzyme is a homodimeric flavoprotein with one FMN cofactor per monomer and catalyzes reduction of nitrocompounds using NADPH. The structure exhibits an alpha + beta-fold, and is comprised of a central domain and an excursion domain. The overall structure of NfsA is similar to the NADPH-dependent flavin reductase of Vibrio harveyi, despite definite difference in the spatial arrangement of residues around the putative substrate-binding site. On the basis of the crystal structure of NfsA and its alignment with the V. harveyi flavin reductase and the NADPH-dependent nitro/flavin reductase of Bacillus subtilis, residues Arg(203) and Arg(208) of the loop region between helices I and J in the vicinity of the catalytic center FMN is predicted as a determinant for NADPH binding. The R203A mutant results in a 33-fold increase in the K(m) value for NADPH indicating that the side chain of Arg(203) plays a key role in binding NADPH possibly to interact with the 2'-phosphate group.

Amino Acid Sequence↗

PubMed2000

Estimating genotype relative risks in case-parental control studies: an optimal weighting approach.

The "case-parental control study" is a novel study design. It can quantify the relations between candidate genes and disease risk. Previous authors have proposed noniterative methods for estimating "genotype relative risks" (GRRs) in case-parental control studies. Here the authors propose yet another noniterative method. The new method is simple. It involves taking certain weighted averages with weights chosen according to one's educated guess about the likely values of the true GRRs. Monte Carlo simulation shows that the new estimators are approximately unbiased and that they have smaller variances than the previous estimators.

Adult↗

PubMed2000

The decline of porcine sperm motility by geldanamycin, a specific inhibitor of heat-shock protein 90 (HSP90).

Sperm motility is an important parameter for fertility. The molecular mechanisms of mammalian sperm motility are still largely undefined. Our previous observations suggested that heat shock protein 90 (HSP90) may be associated with porcine sperm motility. The aim of the present study was to further characterize the plausible novel function of HSP90 on sperm motility. Semen from normal, sexually mature boars with sperm motility higher than 80% was used. An HSP90-specific inhibitor, geldanamycin (GA), was added to diluted semen at 0.5, 1.0, 2.5 or 5.0 microg/mL and the semen was then incubated at 37 degrees C for 15, 30, 45 or 60 min. Sperm motility was determined by using computer-assisted semen analyzer at the end of incubation. The results indicated that GA significantly reduced sperm motility in a dose and time dependent manner. Moreover, incubation of semen with 5.0 microg/mL GA for 15 min completely stopped sperm motility. To test the reversibility of the GA effect on sperm motility, GA was removed after 30 min incubation and was replaced with fresh extender alone or with extender plus 5 mM caffeine, then incubated for another 15, 30, 45 or 60 min. The results showed that simply removing GA did not reverse the inhibitory effect on sperm motility, while adding caffeine partially reversed this inhibitory effect. However, the effect of 2.5 or 5.0 microg/mL GA was not reversed by caffeine. Considering the specificity of GA targeting to HSP90, the above observations suggested that HSP90 may play a crucial role in regulating porcine sperm motility.

Animals↗

PubMed2000

cDNA cloning of pig testicular lactate dehydrogenase-C, thermal stability of the expressed enzyme, and polymorphism among strains.

Pig testicular lactate dehydrogenase-C (LDHC) cDNA was cloned and sequenced. The deduced sequence of 332 amino acids from pig LDHC shows 73% and 67% identity with that of pig LDHA (muscle) and LDHB (heart) respectively, whereas pig LDHA and LDHB isozymes shows 74% sequence identity. Pig and mouse LDHC cDNAs were subcloned into bacterial expression vector, and the expressed pig LDHC isozyme was shown to be as thermally stable as mouse LDHC isozyme. Pig genomic DNAs from Chinese Meishan, English Yorkshire, Danish Landrace and American Duroc were shown to exhibit polymorphic sites for restriction enzymes EcoRI, BamHI and PstI.

Animals↗

PubMed2000

Expression of GPC3, an X-linked recessive overgrowth gene, is silenced in malignant mesothelioma.

Gene expression changes in rat asbestos-induced malignant mesothelioma (MM) cells were investigated by differential mRNA display. A mRNA transcript identified by this approach was abundant in normal rat mesothelial cells but not expressed in rat MM cell lines. Northern blot analysis confirmed that this transcript is uniformly silenced in rat MM cell lines and primary tumors. Nucleotide sequence analysis revealed that this transcript is encoded by the rat glypican 3 gene (GPC3), whose human homolog is mutated in the Simpson-Golabi-Behmel overgrowth syndrome. Allelic loss at the GPC3 locus was infrequent (6.9%) in MM cell lines, and no mutations were found. GPC3 transcript levels were markedly decreased in 16 of 18 primary tumors and 17 of 22 human MM cell lines. Most of the cell lines were shown to have aberrant methylation of the GPC3 promoter region. In two of four human MM cell lines tested, GPC3 expression was restored after 2-deoxy 5-azacytidine (DAC)-mediated demethylation of its promoter region. Ectopic expression of GPC3 inhibited in vitro colony formation of human MM cells. Collectively, these data suggest that down-regulation of GPC3 is a common occurrence in MM and that GPC3, an X-linked recessive overgrowth gene, may encode a negative regulator of mesothelial cell growth.

Alleles↗

PubMed2000

Foley catheter action in the nasopharynx: a cadaveric study.

OBJECTIVES: To determine the action of the Foley catheter in the posterior nasal cavity in relation to balloon volume, and to deduce its implications in the treatment of posterior epistaxis. DESIGN: Human cadaveric study. MATERIALS: Twenty nasal fossae of 10 adult cadavers. INTERVENTIONS: A Foley catheter (size 14) was inserted into the nasopharynx via each nostril. The catheter balloon was inflated to its recommended maximum volume with 15 mL of water. Firm traction was applied to the catheter. Colored liquid was instilled into the ipsilateral aspect of the nasal cavity, and liquid leakage into the contralateral side was monitored using a nasoendoscope. The balloon was reduced in volume by 1-mL steps, and the same fluid infusion and documentation procedures were performed for each reduced volume until the balloon slipped out of the nose. The procedure was repeated in the opposite nostril. MAIN OUTCOME MEASURES: Successful choanal sealing and anterior balloon shift into the nasal fossa in relation to the balloon size. RESULTS: The Foley catheter balloon sealed the choana without any leakage of infused liquid into the contralateral side at appropriate inflation volumes in 17 (85%) of 20 nasal fossae. Complete sealing between volumes of 12 and 15 mL was achieved in 13 fossae (65%), between 11 and 15 mL in 10 nasal fossae (50%), and between 5 and 15 mL in 3 nasal fossae (15%). Failure to seal at any volume occurred in 3 nasal fossae (15%). Bimodal seal (ie, complete seal at high [15 mL] and low volumes [4-7 mL], but leakage in intermediate volumes) occurred in 3 nasal fossae (15%). The balloon remained in the nasopharynx under traction and did not slip past the choanal rim to encroach on the middle and inferior turbinates until the balloon volume was reduced to between 4 and 7 mL. The balloon slid out of the nose at a volume of 5 mL or less. The inflation volumes ranging from 8 to 12 mL were statistically more effective in sealing the choana than lower volumes (4-7 mL) (P<.002, chi(2) test). CONCLUSIONS: At different inflation volumes, the Foley catheter balloon acts primarily (1) as a platform for an anterior gauze pack (at 4-15 mL); (2) as an effective seal of the choana (at 8-15 mL usually and at 4-7 mL occasionally); and (3) as a compressor of the region behind the middle and inferior turbinates (at 4-7 mL), provided that the balloon under traction does not slip out of the nose.

Adult↗

PubMed2000

Fish bone inhalation in infancy.

Inhalation of sharp bones by infants is an uncommon but hazardous occurrence. management relies not only on a high index of clinical suspicion and timely treatment but also demands expertise in therapeutic bronchoscopy. The potential complications and the management of this condition are reviewed.

Animals↗