PubMed Health⌕ Search

Biomedical subjects

G L Hu

Publications and source records attributed to G L Hu.

At least 19 recordsLinked to original sources
PubMed2003

ELF magnetic fields induce internalization of gap junction protein connexin 43 in Chinese hamster lung cells.

We have previously demonstrated that exposure of Chinese hamster lung (CHL) cells to 50 Hz magnetic fields (MFs) and/or 12-O-tetradecanoylphorbol-3-acetate (TPA)-inhibited gap junctional intercellular communication (GJIC). To explore and compare the mechanisms of GJIC inhibition induced by extremely low frequency (ELF) MF and TPA, the number and localization of connexin 43 (C x 43) were studied. The localization of C x 43 was determined with indirect immunofluorescence histochemical analysis and detected by confocal microscopy after exposing CHL cells to 50 Hz sinusoidal magnetic field at 0.8 mT for 24 h without or with TPA (5 ng/ml) for the last 1 h. The C x 43 levels in nuclei and in cytoplasm were examined by Western blotting analysis. The results showed that the cells exposed to MF and/or TPA displayed individual plaques at regions of intercellular contact, which were fewer than the normal cells in number, while the number of C x 43 in cytoplasm increased and congregated near the nuclei. Western blot analysis further demonstrated the quantity of changes in location of Cx43. These results suggest that reduction of C x 43 at regions of intercellular contact may be one of the mechanisms of GJIC inhibition induced by ELF MF.

Animals↗
PubMed2002

Helicobacter pylori cagA and vacA cytotoxin genes in Changsha, China.

Cytotoxin-associated protein (cagA) and the vacuolating cytotoxin (vacA) encoded by cagA and vacA genes are virulence determinants of Helicobacter pylori. In earlier studies among Chinese patients, all H. pylori strains were cagA-positive and vacAs1a/m2 type. Here, we determine the cagA, vacA and allele status of H. pylori strains isolated from patients with upper gastrointestinal symptoms in Changsha, China. Forty strains of H. pylori isolated from patients with peptic ulcer disease between March 1997 and August 1999 were recovered from storage at -80 degrees C and studied by the polymerase chain reaction (PCR) for cagA and vacA genotypes. cagA was positive in 75% of H. pylori isolates. Patients with peptic ulcer demonstrated cagA in 83% (15/18), compared with 68% (15/22) patients with superficial gastritis. vacAs1 allele was carried in 82.5% (33/40) isolates, of which 52.5% (21/40) were subtype vacAs1a/m2 and 17.5% (7/40) were subtype vacAs1b/m2.

Antigens, Bacterial↗
PubMed2001

ELF magnetic field inhibits gap junctional intercellular communication and induces hyperphosphorylation of connexin43 in NIH3T3 cells.

The effects of extremely low frequency (ELF) magnetic field on gap junctional intercellular communication (GJIC), protein levels, and phosphorylation of connexin43 (Cx43) were studied in NIH3T3 cells. The suppression of GJIC by 24 h, 50 Hz, 0.8 mT ELF magnetic field, 2 h, 3 ng/ml 12-O-tetradecanoylphorbol-13-acetate (TPA), or ELF combined with TPA treatment was confirmed by the fluorescence recovery after photobleaching (FRAP) analysis with a confocal microscope. The results showed that ELF or TPA exposure induced 50-60% inhibition of GJIC (P < 0.01). ELF combined with TPA enhanced the inhibition of GJIC. Western blot analysis using Cx43 specific antibodies showed obviously decreasing non phosphorylated Cx43 (P(0)) induced by ELF and/or TPA exposure. On the other hand, cells treated with ELF and/or TPA displayed a hyperphosphorylated Cx43 band (P(3)). However, there was no obvious changes in the level of Cx43 protein. The results implied that the P(3) band appeared to result from phosphorylation of P(0). But it remains possible that upon the ELF exposure P(0) is converted to P(1), P(2) or both and that P(3) is formed from P(1) or P(2) resulting in the observed hyperphosphorylation pattern. From the present study, we conclude that ELF magnetic field inhibits GJIC and the main mechanism is the hyperphosphorylation of Cx43.

3T3 Cells↗
PubMed2001

Polycolonization of Helicobacter pylori among Chinese subjects.

OBJECTIVE: To investigate the situation among Chinese patients with regard to infection with multiple strains of Helicobacter pylori. METHODS: Biopsy specimens for culture of H. pylori were obtained from gastric antrum, body and fundus of 20 patients during endoscopic investigation of upper gastrointestinal symptoms. H. pylori was identified by culture from one site in 16 and two or more sites in 10 of the 16 patients. Five isolated colonies of six strains of H. pylori from gastric antrum were subcultured and used for further analysis. Antibiotic susceptibility to metronidazole and clarithromycin was determined by disk diffusion test. Protein profiles of isolates were compared by sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE). DNA diversity of the isolates was determined by arbitrarily primed polymerase chain reaction (AP-PCR) fingerprinting. RESULTS: Of the 10 patients with multiple isolates, 70% (7/10) exhibited variation in susceptibility to metronidazole and 20% (2/10) to clarithromycin between different sites. In 83% of (5/6) single colonies, no variability was seen in metronidazole and clarithromycin susceptibility; they were either susceptible or resistant. Protein profiles of all isolates by SDS-PAGE were similar. Isolates from different patients produced clearly different AP-PCR fingerprints. In 50% of H. pylori strains isolated from different sites of the stomach, genetic diversity was demonstrated by different AP-PCR fingerprints. In 67% (4/6) strains, five single-colony fingerprints were similar. CONCLUSIONS: Genetic variability has been found in H. pylori strains. Individual patients are infected with a single predominant genotype at a single site but can be colonized by multiple strains, and they may show different antibiotic susceptibilities. Individual colonies of the H. pylori population from a single site may not always yield identical DNA fingerprints and antibiotic sensitivities.

Adult↗
PubMed2000

The effect of 50 Hz magnetic field on GCSmRNA expression in lymphoma B cell by mRNA differential display.

Magnetic fields (MFs) of various characteristics can lead to plethora effects in biological system. From a molecular point of view, we hypothesized that there must be a fundamental difference in gene expression between the MF exposed and the unexposed cell. To identify the classes of genes that are regulated, 0.8 mT 50 Hz MF-induced changes in gene expression were examined in a Daudi cell culture using differential display and reverse transcriptase-polymerase chain reaction. A candidate cDNA (signatured as MF-CB) that was observed in the sham-exposed but not in MF-exposed cultures was recovered and reamplified. After verification by Northern blot, the cDNA was cloned and sequenced. It was found that 254-base pair of 5'-end MF-CB cDNA clone was identical to gcs in open reading frame (ORF) range. Based on the preliminarily sequence, the prolonged length of 5'-end MF-CB cDNA was obtained by PCR amplification and its sequence analysis showed the same results as its original fragment. In order to further determine whether MF-CB cDNA is from gcs, two Northern blots were probed with gcs and MF-CB cDNA, respectively, and the data revealed signals of the same size and expression pattern on the two probe filters, which demonstrated that MF-CB is an EST (expression sequence tag) of gcs. gcs is a gene, identified recently (GenBank accession number D89866), encoding ceramide glucosyltransferase (GCS), which has been implicated as a causal element in human cell growth and differentiation. In an additional experiment, time-dependent changes in the transcription of gcs induced by 0.8 mT MF were observed by Northern blot with a sharp and reproducible inhibition effect after 20 min exposure and a reduction after 20-24 h exposure. The study demonstrates for the first time that 50 Hz MF can lead to changes in gcs transcription, which provides a new clue to elucidate the mechanism by which MF influence cell growth and differentiation.

Amino Acid Sequence↗
PubMed2000

[Determination of six ginsenosides in Panax species by high performance liquid chromatography].

A method for the determination of six major ginsenosides in panax species by high performance liquid chromatography (HPLC) with UV detection at 203 nm is described. The six major ginsenosides, which were reported to account for more than 90% of the total ginsenosides content of the panax species' root, were successfully separated using gradient HPLC. The column to be used was a Cosmosil-C18 reversed-phase, 4.6 mm i.d. x 250 mm, 5 microns (Japan), connected with a C18 guard column and the mobile phase was acetonitrile and water. The calibration curves of the six ginsenosides were all linear over the range of 25 mg/L-300 mg/L with good correlation coefficients (> 0.99). The recoveries for the ginsenosides were all above 80%. For real samples and recovery study, the major ginsenosides were ultrasonically extracted by methanol. The extracts were evaporated to 1 mL, under vacuum, at about 50 degrees C and then diluted by methanol. Just prior to HPLC analysis, the sample solutions were filtered using a C18 cartridge. This method has been successfully applied to the analysis of four commercial panax samples.

Chromatography, High Pressure Liquid↗
PubMed1999

Follow-up recommendations for patients with American Joint Committee on Cancer Stages I-III malignant melanoma.

BACKGROUND: Guidelines for follow-up of melanoma patients are not established. In 1987, a follow-up protocol was instituted at the Yale Melanoma Unit to improve upon the detection of disease recurrence in patients with American Joint Committee on Cancer Stage I-III cutaneous melanoma. The follow-up protocol consists of a patient education program and a surveillance schedule based on stage of disease. METHODS: The authors retrospectively reviewed the records of 373 patients who were seen and followed according to the surveillance protocol in the Yale Melanoma Unit between January 1988 and December 1994 to determine 1) the time interval between the initial visit and recurrence; 2) the most common method of detecting recurrences; 3) whether the surveillance schedule or the patient detects more recurrences, i.e., asymptomatic recurrences versus symptomatic recurrences; 4) whether there is any survival difference between asymptomatic and symptomatic recurrences. RESULTS: The 5-year overall survival rates for Stage I, II, and III patients were 95%, 72%, and 52%, respectively. Of the 78 recurrences, 44 (56%) were detected by physician-directed surveillance examinations and 34 (44%) by patients. Most recurrences were found within the first (47%) or second (32%) year of follow-up. The estimated 6-month hazard rates for death or recurrence were 0.0044, 0.0088, and 0.0278 for Stage I, II, and III patients, respectively. The group of asymptomatic patients with recurrence had a survival advantage over the symptomatic recurrence group. In addition, patients with locoregional recurrence had better survival than those with distant recurrence. CONCLUSIONS: Although many recurrences arise rapidly and are recognized early by patients, in this study more than half were found by surveillance examinations before symptoms were manifest. Based on the hazard ratio for recurrences, the authors recommend the following surveillance schedules in addition to the patient education program for detection of recurrences: 1) Stage I, annually; 2) Stage II, every 6 months for Years 1-2 and annually thereafter; 3) Stage III, every 3 months for Year 1, every 4 months for Year 2, and every 6 months for Years 3-5; 4) at Year 6 and beyond, all patients should have surveillance annually, due to the risk of late recurrence and/or metachronous multiple primaries.

Adolescent↗
PubMed1999

Neutropenic infections in 100 patients with non-Hodgkin's lymphoma or Hodgkin's disease treated with high-dose BEAM chemotherapy and peripheral blood progenitor cell transplant: out-patient treatment is a viable option.

A retrospective analysis was performed on 100 patients with non-Hodgkin's lymphoma (NHL, n = 75) or Hodgkin's disease (HD, n = 25) who underwent peripheral blood progenitor cell transplant (PBPCT) following high-dose chemotherapy (HDCT) with BCNU, etoposide, cytarabine and melphalan (BEAM) between March 1994 and June 1997. Following PBPCT and until engraftment all patients received oral ciprofloxacin and fluconazole, patients with positive Herpes simplex virus serology received acyclovir and 91 patients received filgrastim. The median days of neutropenia and days to an absolute neutrophil count (ANC) >500/mm3 were 6 and 9, respectively. Febrile neutropenia occurred in 68 patients. Gram-positive bacteremia occurred in 14 patients. No gram-negative infections, invasive fungal infections, intensive care visits or deaths occurred during the period of neutropenia or in the first 30 days following transplant. In multivariate logistic regression the risk of development of any infection was associated only with the duration of neutropenia (P = 0.02) and the risk of bacteremia was associated only with the number of CD34+ cells infused (P = 0.046). Among 49 patients treated in the outpatient setting, 14 (28%) were never admitted. High-dose chemotherapy with BEAM supported by PBPCT, prophylactic antibiotics and filgrastim resulted in a low incidence of infections and no acute mortality. WBC engraftment occurred rapidly allowing for a predictable course during which lengthy hospital stays and amphotericin therapy could be avoided.

Adult↗
PubMed1999

Assessment of cardiac and pulmonary function in adult patients with Hodgkin's disease treated with ABVD or MOPP/ABVD plus adjuvant low-dose mediastinal irradiation.

We evaluated the long-term effects of combined modality therapy (CMT) with adriamycin, bleomycin, vinblastine, dacarbazine (ABVD) or mechlorethamine, vincristine, prednisone, procarbazine (MOPP)/ABVD plus adjuvant low-dose (< 30 Gy) involved-field radiation therapy (LDRT) on cardiac and pulmonary functions in adult patients with Hodgkin's disease (HD). Adjuvant LDRT (mean dose, 2340 cGy) to the mediastinum was administered to 24 patients after chemotherapy with MOPP/ABVD (n = 10) and ABVD (n = 14). The mean doses of doxorubicin and bleomycin were 233 mg/m2 and 92 IU/m2, respectively. Cardiac and pulmonary function tests were performed in all patients and, when available, were compared with pretreatment studies. After a median follow-up of 6.3 years, none of the patients had cardiac or pulmonary symptoms. A 4.7% overall decrease in left ventricular ejection fraction (LVEF) was observed (p = 0.03), but only one patient had a mildly decreased LVEF (47%). Diastolic function, LVEF, and left ventricular volume remained within the normal range in the other 23 patients. Mild pulmonary function study abnormalities occurred in 8 of 24 patients, 6 of whom were cigarette smokers. There were no significant changes in total lung capacity and forced vital capacity (FVC) values, but there was a 3% overall decrease in FEV1/FVC ratio (p = 0.05). In adult patients with HD, adjuvant LDRT after chemotherapy with ABVD or MOPP/ABVD did not result in a significant incidence of permanent pulmonary or cardiac toxicity after more than 6.3 years of median follow-up. Further studies are warranted to fully evaluate the impact of such therapy on cardiopulmonary function.

Adolescent↗
PubMed1998

Assessment of pulmonary and cardiac function after high dose chemotherapy with BEAM and peripheral blood progenitor cell transplantation.

BACKGROUND: Limited information is available regarding the cardiac and pulmonary effects of high dose chemotherapy (HDCT) and autologous peripheral blood progenitor cell (PBPC) transplantation. METHODS: The authors evaluated cardiac and pulmonary function after BEAM (BCNU 300 mg/m2, etoposide 400 mg/m2/day x 3 days, cytosine arabinoside 200 mg/m2/day x 4 days, and melphalan 140 mg/m2), HDCT, and PBPC transplantation in 26 patients with non-Hodgkin's lymphoma or Hodgkin's disease. Therapy prior to BEAM included doxorubicin (25 patients), bleomycin (6 patients), and mediastinal irradiation (4 patients). All patients had pulmonary function tests (PFTs) and equilibrium radionuclide angiography before and at a median of 57 weeks after transplantation. RESULTS: Prior to high dose therapy, 8 patients had abnormal PFTs, including 6 with a diffusing capacity of the lung for carbon monoxide (DLCO) <70% of predicted value. At the time of reevaluation after HDCT, all patients included in the study were in complete remission, and none had received additional therapy after transplantation. At a median of 77 weeks after transplantation, none of the patients had cardiac or pulmonary symptoms. Moreover, there were no significant changes in total lung capacity, forced vital capacity, forced expiratory volume in 1 second/forced vital capacity, DLCO, or left ventricular ejection fraction values when compared with baseline studies. CONCLUSIONS: The authors concluded that HDCT with BEAM and PBPC transplantation did not result in significant cardiac or pulmonary toxicity, even in patients with borderline pretransplantation PFT values. Further studies of patients undergoing HDCT and PBPC transplantation are needed.

Adult↗
PubMed1998

Circulating Th1 and Th2 cytokines in patients with hepatitis C virus infection.

The imbalance of T-helper (Th) lymphocyte cytokine production may play an important role in immunopathogenesis of persistent hepatitis C virus (HCV) infection. To know whether an imbalance between Th1 and Th2 cytokines is present in chronic HCV infection, serum levels of Th1 cytokines, interferon gamma (IFN-gamma) and interleukin (IL)-2, and Th2 cytokines, IL-4 and IL-10, were measured using enzyme-linked immunosorbent assay in this study. Eighteen individuals with chronic HCV infection, 11 healthy subjects as normal controls and 10 chronic HBV infected patients as disease controls were observed. The results showed that the levels of Th2 cytokines (IL-4 and IL-10) were significantly increased in chronic HCV infected patients compared with normal controls (IL-4: 30.49+/-17.55 vs. 14.94+/-13.73, pg/ml, P<0.025; IL-10: 50.30+/-19.59 vs. 17.87+/-9.49, pg/ml, P<0.001). Similarly, the levels of Th1 cytokine, IL-2, was also elevated in individuals with chronic HCV infection when compared with normal controls (IL-2: 118.53+/-95.23 vs. 61.57+/-28.70, pg/ml, P<0.05). However, Th1 cytokine IFN-gamma level was not significantly changed during HCV infection (IFN-gamma: 28.09+/-15.65 vs. 24.10+/-15.61, pg/ml, P>0.05). Furthermore, the elevated levels of Th2 cytokines are greater than Th1 cytokines in HCV infection. Thus, the study indicates that an enhanced Th2 responses are present during chronic HCV infection, which may partly be responsible for the persistence of HCV infection.

Adult↗
PubMed1998

Seroprevalence of Helicobacter pylori infection in patients with hepatitis B.

Helicobacter pylori infection has been investigated extensively in immunocompromised hosts, such as those with acquired immunodeficiency syndrome (AIDS) and organ transplant recipients. However, few reports on H. pylori prevalence in individuals with chronic HBV infection are available. The aim of this serological study is to investigate H. pylori prevalence in patients with hepatitis B. Ninety-six consecutive hospitalised patients with chronic hepatitis B were studied, together with 104 age-matched healthy individuals of similar socioeconomic status and with no evidence of hepatitis B virus infection or liver diseases. Serum samples from both groups were tested for specific IgG antibodies to H. pylori, using enzyme-linked immunosorbent assay (ELISA). Of the 96 patients with hepatitis B, 55 (57.3%) were positive for serum IgG anti-H. pylori, significantly greater than in the control group of 104, where 44 (42.3%) were positive (P < 0.05). In addition, the seroprevalence of H. pylori in the 45 patients who were positive for hepatitis B envelope antigen (HBeAg) and/or HBV-DNA was 75.6% (34), compared to 41.2% (21) in the 51 patients who were negative (P < 0.005). An increase in H. pylori prevalence is present in patients with chronic hepatitis B. Further study is needed to determine whether eradication of H. pylori will benefit these patients.

Adolescent↗
PubMed1993

Molecular cloning, sequencing and expression of core and NS3 fragments of HCV from patients with HCV infection.

Fragments of core and NS3 of hepatitis C virus-Hunan (HCV-Hun) were cloned by RT-PCR and gene recombinant techniques from blood samples collected in Hunan Province, China. In comparison with sequences of our samples with those of HCV-US and HCV-J, the homologies of nucleotides and amino acids were about 90%, indicating that fragments of core and NS3 of HCV-Hun were in a relative conserved region of HCV. Two fusion proteins containing the peptides coded by HCV core (MBP-HCV core) and HCV. NS3 (MBP-HCV. NS3-Gal) were expressed by Escherichia Coli with recombinant plasmids. The specific HCV antigenicity of the two fusion proteins were identified by western blotting. Therefore, MBP-HCV. core and MBP-HCV.NS3-Gal were found useful for anti-HCV assay.

Amino Acid Sequence↗
PubMed1992

[Detection of serum antibody against hepatitis C virus in patients with hepatitis and liver diseases].

Antibody against hepatitis C virus (anti-HCV) was tested in 658 cases of hepatitis and liver diseases with ELISA, ninety of these cases were positive, with a total infection rate of 13.68% (90/658). The positive rate of anti-HCV was highest in patients with chronic severe hepatitis (33.78%) and CAH accompanied by cirrhosis of liver(31.58%). The infection rate in other types of hepatic diseases in order of frequency was as follows: fulminant hepatitis (18.18%), CAH without cirrhosis (15.13%), subacute severe hepatitis (13.43%), CPH (5.88%), primary hepatocellular carcinoma (3.85%), and acute hepatitis (2.42%). Serological markers of HBV infection were detectable concomitantly in 77 of the 90 cases who were anti-HCV positive, but there was no evidence of mutual inhibition of viral replication. There was neither appreciable difference in the level of hyperbilirubinemia in cases of hepatitis with or without anti-HCV, nor significant diversity in the number of death between cases of severe hepatitis with and without anti-HCV.

Adult↗
PubMed1990

[Epidemiological characteristics and control of filariasis in Hunan Province].

Of 98 counties or cities in Hunan Province, 55 were endemic areas of filariasis. The average microfilaria rate was 5.64% (180,046/3,194,102), and the incidence of advanced filariasis, including elephantiasis and hydrocele was 3.29%. The number of filariasis patients in the whole province was estimated to be 1.63 million, comprising 1.25 million of microfilaremia cases, Culex fatigans and Anopheles hyrcanus sinensis were the major vectors of bancroftian and malayan filariasis respectively in the province. Control strategies concentrated on the elimination of infection source were implemented on the basis of extensive investigations, and the ensuing examination and treatment of filariasis cases in pilot areas prior to the implementation of province-wide filariasis control. Repeated blood examinations and medications for 3-4 times were carried out in hypo-endemic areas of malayan filariasis, whereas mass treatment with hetrazan-medicated salt containing 0.2% to 0.5% DEC was carried out in meso- and hyper-endemic areas of bancroftian filariasis as well as those situated in remote mountainous regions for six months. Subsequent evaluation and clearance checking showed that microfilaria rate of the whole province has already dropped to less than 1%. That filariasis was basically eliminated in Hunan was recognized by the Evaluation Mission Group sent by the Ministry of Public Health in 1986.

Animals↗
PubMed1988

Expression of the cDNA for mouse beta-nerve growth factor protein in Escherichia coli.

The cDNA coding for the mature beta-nerve growth factor (beta-NGF) has been cloned into a plasmid expression vector, pAS1, and expressed in Escherichia coli. The cDNA fragment in pAS1 is under the control of strong phage transcriptional and translational initiation elements that provide for regulated expression of cloned genes in E. coli. The protein, produced in bacteria at a level of about 0.0005-0.1% of cell protein, was purified by ammonium sulfate precipitation and ion exchange chromatography. The recombinant NGF was biologically active in the PC12 neurite outgrowth assay, and formed a band at Mr of about 11,000 to 12,000, when electrophoresed on sodium dodecyl sulfate-polyacrylamide gel and Western-blotted.

Animals↗