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Biomedical subjects

J Hu

Publications and source records attributed to J Hu.

At least 91 records · Page 5Linked to original sources
PubMed2002

Oxytocin stimulates secretion of prostaglandin F(2alpha) from endometrial cells of swine in the presence of progesterone.

Oxytocin (OT) stimulates endometrial secretion of prostaglandin (PG) F(2 alpha) during corpus luteum regression in swine but there is differential responsiveness to OT among endometrial cell types. To determine if progesterone influenced responsiveness of luminal epithelial, glandular epithelial, and stromal cells to 100 nM OT during luteolysis in swine, cells were isolated from endometrium of 15 gilts by differential enzymatic digestion and sieve filtration on day 16 postestrus and cultured continuously in the presence of 0, 10 or 100 nM progesterone. For phospholipase C (PLC) activity and PGF(2 alpha) secretion, stromal cells were most responsive to OT (P<0.01) in the absence of progesterone, whereas luminal epithelial cells were unresponsive and glandular epithelial cells displayed an intermediate response to OT (P<0.09). Progesterone enhanced PLC activity linearly in glandular epithelial cells (P<0.05) and influenced it quadratically in stromal cells (P=0.05). The effect of OT and progesterone on PLC activity in luminal epithelial cells was not significant, and progesterone did not increase PLC activity in response to OT in any cell type. Culture in the presence of progesterone, enhanced PGF(2 alpha) secretion in response to OT in luminal epithelial cells (P<0.05) but not in glandular epithelial or stromal cells. Progesterone also increased overall PGF(2 alpha) release from glandular epithelial (P<0.05) and stromal cells (P<0.06) across both levels of OT treatment. These results indicate that progesterone enhanced PGF(2 alpha) secretion from luminal epithelial cells in response to OT and increased basal PGF(2 alpha) release from glandular epithelial and stromal cells.

Animals↗
PubMed2002

Differences in mandibular distraction osteogenesis after corticotomy and osteotomy.

Corticotomy or osteotomy was performed on opposing sides of the mandibles in 18 goats. A custom-made distractor was used to lengthen the mandible at a rate of 1 mm/day for 10 days (total 10 mm elongation). Six goats were sacrificed respectively at 2, 4 and 8 weeks after completion of distraction. The distracted calluses were harvested and processed for radiographic, histologic, and scanning electron microscopic evaluation as well as Ca/P ratio analysis. The regenerate bone in the corticotomy side showed more bone formation and earlier mineralization than in the osteotomy side. The results of this study suggest that preservation of intramedullary vessels is beneficial to bone regeneration following mandibular osteodistraction, and that performing corticotomy may be a simple but effective way to promote the maturity of the distracted callus and shorten the time for fixation.

Animals↗
PubMed2002

Renal cell carcinoma and occupational exposure to chemicals in Canada.

This study assesses the effect of occupational exposure to specific chemicals on the risk of renal cell carcinoma in Canada. Mailed questionnaires were used to obtain data on 1279 (691 male and 588 female) newly diagnosed, histologically confirmed renal cell carcinoma cases and 5370 population controls in eight Canadian provinces, between 1994 and 1997. Data were collected on socio-economic status, smoking habit, alcohol use, diet, residential and occupational histories, and years of exposure to any of 17 chemicals. Odds ratios (ORs) and 95% confidence intervals (CIs) were derived using unconditional logistic regression. The study found an increased risk of renal cell carcinoma in males only, which was associated with occupational exposure to benzene; benzidine; coal tar, soot, pitch, creosote or asphalt; herbicides; mineral, cutting or lubricating oil; mustard gas; pesticides; and vinyl chloride. Compared with no exposure to the specific chemical, the adjusted ORs were 1.8 (95% CI = 1.2-2.6), 2.1 (1.3-3.6), 1.4 (1.1-1.8), 1.6 (1.3-2.0), 1.3 (1.1-1.7), 4.6 (1.7-12.5), 1.8 (1.4-2.3) and 2.0 (1.2-3.3), respectively; an elevated risk was also associated with exposure to cadmium salts and isopropyl oil. The risk of renal cell carcinoma increased with duration of exposure to benzene, benzidine, cadmium, herbicides and vinyl chloride. Very few females were exposed to specific chemicals in this study; further research is needed to clarify the association between occupational exposure to chemicals and renal cell carcinoma in females.

Adult↗
PubMed2002

Active and passive smoking and the risk of stomach cancer, by subsite, in Canada.

This study assessed the influence of active and passive smoking on the risk of stomach cancer by subsite. Mailed questionnaires were used to obtain information on 1171 newly diagnosed histologically confirmed stomach cancer cases and 2207 population controls between 1994 and 1997 in eight Canadian provinces. Data were collected on socio-economic status, lifestyle and passive smoking status. Odds ratios (OR) and 95% confidence intervals (95% CI) were derived by logistic regression. Compared with those who had never smoked, there was strongly increased risk for ex- and current smokers among subjects with cardial stomach cancer. For men with cardial cancer, the adjusted ORs were 1.9 (95% CI 1.2-3.0) and 2.6 (95% CI 1.6-4.3) for ex-smokers and current smokers, respectively, with a similar pattern among women. Among men, the adjusted ORs were lower for subsites of stomach cancer other than cardia. These findings suggest that active and passive smoking may play an important role in the development of cardial stomach cancer.

Adult↗
PubMed2001

Deletion mapping of 6q21-26 and frequency of 1p36 deletion in childhood endodermal sinus tumors by microsatellite analysis.

The most common malignant germ cell tumor of early childhood is the endodermal sinus tumor (CEST), also known as yolk sac tumor. Previous cytogenetic studies of CEST have demonstrated recurrent deletion of distal regions of chromosomes 1p and 6q. Studies utilizing comparative genomic hybridization have likewise demonstrated loss of distal 6q, however these studies show discrepant data concerning chromosome 1 abnormalities. This study analyses 18 CESTs for loss of heterozygosity (LOH) of distal chromosome 6q utilizing 17 microsatellite markers and 13 tumors were analysed for LOH of distal 1p using two microsatellite markers. LOH of 6q was found in 13/18 tumors (72 %). This data confirms that loss of genetic material on 6q is one of the most common abnormalities in CESTs and narrows the region of loss, enabling candidate tumor suppressor genes to be identified and analysed. In addition, LOH of 1p36 was identified in five of 11 informative tumors, clarifying prior conflicting data and confirming that 1p deletion is a common event in CESTs.

Child, Preschool↗
PubMed2001

Nuclear inelastic x-ray scattering of FeO to 48 GPa.

The partial density of vibrational states has been measured for Fe in compressed FeO (wüstite) using nuclear resonant inelastic x-ray scattering. Substantial changes have been observed in the overall shape of the density of states close to the magnetic transition around 20 GPa from the paramagnetic (low pressure) to the antiferromagnetic (high pressure) state. The results indicate that strong magnetoelastic coupling in FeO is the driving force behind the changes in the phonon spectrum of FeO. The paper presents the first observation of changes in the density of terahertz acoustic phonon states under magnetic transition at high pressure.

Journal Article↗
PubMed2001

[Mannose-binding lectin gene site mutations and the susceptibility of rheumatic heart disease].

OBJECTIVE: To investigate the relationship between mannose-binding lectin (MBL) gene exon 1 site mutations and chronic rheumatic heart disease (CRHD). METHODS: Polymerase chain reaction (PCR) and restrictive fragment length Polymorphism (RFLP) were used to investigate the MBL exon 1 alleles in 36 patients with CRHD and 39 normal people. RESULTS: No C and D alleles of MBL gene were found in both groups. Eleven patients had A/B alleles, 1 patient had B/B alleles, 15 normal people had A/B alleles but none of the 39 normal people had B/B alleles. Statistic analyses showed no significant difference between CRHD group and normal group. But when the age of heart-disease-symptom-onset (HDSO) of the CRHD group were considered, we found that the mean HDSO age of patients with B allele was 30 +/- 14 years and the mean HDSO age of patients with AA homozygous was 37 +/- 11 years. P < 0.05. CONCLUSION: MBL gene mutations may not be a main factor of the pathogenesis of CRHD, but MBL deficiency may facilitate the development of CRHD in younger people and accelerate the progress of CRHD. This is consistent with the phenomenon that the most susceptible people of rheumatic heart disease are teenagers.

Adolescent↗
PubMed2001

[Effect of NPS R-467 on PTH secretion of cultured parathyroid cells from secondary hyperparathyroidism patients].

OBJECTIVE: To observe the effect of NPS R-467, a calcimimetic, on PTH secretion of cultured parathyroid cells from severe secondary hyperparathyroidism (SHPT) patient. METHODS: The parathyroid tissue from a severe SHPT patient (iPTH: 2000 pg/ml) who had underwent parathyroidectomy was cultured in medium containing 1.05 mmol/L Ca and 0.8 mmo/L Mg. After 90 minutes' culture, NPS R-467 or NPS S-467, as negative control, with the final concentrations of 25, 50, and 100 nmol/L was added. The supernatant of medium was aspirated after 15, 30, and 60 minutes and iPTH therein was measured by radioimmunoassay. RESULTS: There was no difference between the PTH concentrations in NPS R-467 group and NPS S-467 15 minutes after the reagents were added (1.8 ng/10(5) cells). In the NPS S-467 group, the PTH secretion was elevated along with the culture time, at 60 minutes up to 2.3 ng/10(5) cells. The PTH concentration of NPS R-467 was 80% of that of control group 30 minutes later and 60% of that in control group 60 minutes later. No difference was found among the effects of NPS R-467 at different concentrations. CONCLUSION: The calcimimetic NPS R-467 significantly suppresses the PTH secretion, even in severe uremic hyperparathyroidism patient. It is an effective medicine for hyperparathyroidism.

Aniline Compounds↗
PubMed2001

A four-dimensional generalization of the quantum Hall effect.

We construct a generalization of the quantum Hall effect, where particles move in four dimensional space under a SU(2) gauge field. This system has a macroscopic number of degenerate single particle states. At appropriate integer or fractional filling fractions the system forms an incompressible quantum liquid. Gapped elementary excitation in the bulk interior and gapless elementary excitations at the boundary are investigated.

Journal Article↗
PubMed2001

Angiotensin-converting enzyme degrades Alzheimer amyloid beta-peptide (A beta ); retards A beta aggregation, deposition, fibril formation; and inhibits cytotoxicity.

We have demonstrated that the angiotensin-converting enzyme (ACE) genotype is associated with Alzheimer's disease (AD) in the Japanese population (). To determine why ACE affects susceptibility to AD, we examined the effect of purified ACE on aggregation of the amyloid beta-peptide (A beta) in vitro. Surprisingly, ACE was found to significantly inhibit A beta aggregation in a dose response manner. The inhibition of aggregation was specifically blocked by preincubation of ACE with an ACE inhibitor, lisinopril. ACE was confirmed to retard A beta fibril formation with electron microscopy. ACE inhibited A beta deposits on a synthaloid plate, which was used to monitor A beta deposition on autopsied brain tissue. ACE also significantly inhibited A beta cytotoxicity on PC12 h. The most striking fact was that ACE degraded A beta by cleaving A beta-(1-40) at the site Asp(7)-Ser(8). This was proven with reverse-phase HPLC, amino acid sequence analysis, and MALDI-TOF/MS. Compared with A beta-(1-40), aggregation and cytotoxic effects of the degradation products A beta-(1-7) and A beta-(8-40) peptides were reduced or virtually absent. These findings led to the hypothesis that ACE may affect susceptibility to AD by degrading A beta and preventing the accumulation of amyloid plaques in vivo.

Alzheimer Disease↗
PubMed2001

Multipoint imprinting analysis indicates a common precursor cell for gonadal and nongonadal pediatric germ cell tumors.

Pediatric germ cell tumors (GCTs) commonly arise at extragonadal sites. It has been proposed that nongonadal GCTs arise from ectopic primordial germ cells that have aberrantly migrated during embryogenesis. During a time between their migration and development to mature gametes, primordial germ cells are characterized by their lack of imprinting, which can be assessed by the evaluation of allelic gene expression and DNA methylation in differentially methylated control regions. To elucidate the cellular origin of nongonadal GCTs, we evaluated the imprinting status of 21 gonadal and 21 nongonadal pediatric GCTs. Allele-specific H19 and IGF-2 expression was assessed with reverse transcription-PCR followed by digestion at polymorphic restriction sites. DNA methylation was evaluated after bisulfite modification, PCR amplification, and restriction digestion at a consistently methylated CpG dinucleotide within the 5' flanking region of the SNRPN gene. These results were compared with genetic gains and losses determined by comparative genomic hybridization. Seven of 15 informative tumors showed biallelic H19 expression, and 8 of 17 informative tumors showed biallelic IGF-2 expression. The frequency of biallelic gene expression was comparable in gonadal and nongonadal GCTs. Sixteen of 19 gonadal GCTs and 17 of 21 nongonadal GCTs showed absence of methylation of SNRPN consistent with loss of imprinting. One testicular GCT and three nongonadal GCTs showed a somatic methylation pattern. Two ovarian teratomas and one mediastinal teratoma showed only methylated SNRPN, consistent with entry into meiosis. Twenty-one of 22 non-GCT control samples showed a somatic methylation pattern. Gonadal and nongonadal germ cell tumors are derived from primordial germ cells that have consistently lost the imprinting of SNRPN and partly lost imprinting of H19 and IGF-2. Because the imprinting pattern of the latter genes differs from that found in testicular GCTs of adult patients, our data suggest that pediatric GCTs arise from a different stage of germ cell development.

Adolescent↗
PubMed2001

Dynamics of the Mrf-2 DNA-binding domain free and in complex with DNA.

Mrf-2 is a member of a new class of DNA-binding proteins known as the AT-rich interaction domain family or ARID. Chemical shift indices and characteristic NOE values indicate that the three-dimensional structure of the Mrf-2 ARID in complex with DNA is nearly identical to that of the free protein. The backbone dynamics of the Mrf-2 domain free and in complex with DNA have been characterized by (15)N NMR relaxation measurements and model-free analysis. Chemical shift perturbations and dynamic studies suggest that two flexible interhelical loops, the flexible C-terminal tail, and one alpha-helix are involved in DNA recognition, indicating the importance of protein dynamics in DNA binding. Some well-structured regions, in particular the putative DNA-contacting helix, in Mrf-2 show a decrease in the order parameters (S(2)) upon complex formation. The less well-structured loops and the unstructured C-terminus show reduced flexibility upon DNA binding. In addition, the model-free analysis indicates motions on the picosecond to nanosecond and micro- to millisecond time scales at the DNA-binding surface of the bound Mrf-2 ARID, suggesting a model where interactions between the protein and DNA are highly dynamic.

Anisotropy↗
PubMed2001

Modulation of p53 dependent gene expression and cell death through thioredoxin-thioredoxin reductase by the Interferon-Retinoid combination.

We have shown earlier that the IFN-beta and all-trans retinoic acid (RA) combination, but not the single agents, induces death in several tumor cell lines. Employing a genetic technique we have identified several Genes associated with Retinoid-IFN induced Mortality (GRIM). One of the GRIMs was human thioredoxin reductase (TR), a redox enzyme. Since the overexpressed TR augments IFN/RA stimulated cell death, we explored the mechanisms of TR-mediated death. Here we show that TR augments cell death by upregulating the transcriptional activity of p53 tumor suppressor. This process does not involve a physical increase in levels of p53. Using redox inactive mutants of TR and its substrate, thioredoxin (Trx), we demonstrate that IFN/RA-induced regulation of p53 dependent gene expression requires TR and Trx. In contrast-over-expression of wildtype TR or Trx augment the p53 dependent gene expression in response to IFN/RA treatment. Consistent with these results an increased DNA binding activity of p53 was noted in the presence of TR. These studies identify a novel mechanism of p53 mediated cell death regulation involving redox enzymes.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2001

Thioredoxin participates in a cell death pathway induced by interferon and retinoid combination.

Interferons (IFNs) and retinoids are potent tumor growth suppressors. We have shown earlier that the IFN-beta and all-trans retinoic acid combination, but not the single agents, induces death in several tumor cell lines. Employing a genetic approach we have recently identified several Genes associated with Retinoid-IFN induced Mortality (GRIM) that mediate the cell death effect of IFN/RA combination. One of the GRIMs, GRIM-12, was identical to human thioredoxin reductase (TR), an enzyme that controls intracellular redox state. To define the participants of TR mediated death pathway we have examined the role of thioredoxin (Trx), its downstream substrate, and its influence on IFN/RA-induced death regulation. Inhibition of the thioredoxin expression by antisense RNA suppressed cell death. Similarly, a mutant Trx1 lacking the critical cysteine residues blocked cell death. In contrast, overexpression of wildtype thioredoxin augmented cell death. This effect of Trx1 was in part due to its ability to augment cell death via caspase-8. The redox inactive Trx1 mutant inhibits the cell death induced by caspase-8 but not caspase-3. These studies identify a novel mechanism of cell death regulation by IFN/RA combination involving redox enzymes.

Antineoplastic Agents↗
PubMed2001

Increased interleukin-6 of skin and serum in amyotrophic lateral sclerosis.

Studies of skin in amyotrophic lateral sclerosis (ALS) have demonstrated morphological and biochemical alterations. Interleukin-6 (IL-6) has been suggested to have a trophic effect in nerve cells and to have a direct pathogenic role in neurodegenerative central nervous system (CNS) disorders. However, little is known concerning IL-6 in ALS patients. We examined IL-6 immunoreactivity of biopsy specimens of skin and measured serum IL-6 levels from 11 ALS patients and 11 diseased control subjects. IL-6 immunoreactivity was markedly positive in the epidermis and dermal blood vessels and glands and was moderately positive in the reticular dermis in all ALS patients. These optical densities for IL-6 immunoreactivity in ALS patients were significantly higher than in control subjects, and were significantly increased with duration of illness. Serum IL-6 levels were detected in 8 (73%) of 11 ALS patients compared with only 1 (9%) of 11 diseased control subjects. Serum IL-6 levels were significantly correlated with duration of illness in ALS patients and immunoreactivity of IL-6 of the epidermis. These data suggest that the increased levels of serum IL-6 may reflect an increased IL-6 immunoreactivity of skin in ALS patients.

Adult↗
PubMed2001

[Study on the clinical misdiagnosis of hepatolenticular degeneration].

OBJECTIVE: To study the proportion and frequency of misdiagnosis of hepatolenticular degeneration (HLD), diseases easily confused with HLD, and the relation between misdiagnosis and curative effect so as to sum up experience and improve diagnosis. METHODS: 1 011 cases with the confirmed diagnosis of HLD who were hospitalized in the Hospital Affiliated to the Institute of Neurology, Anhui College of TCM from November 1993 to June 2000 were analyzed. Those patients who had attended two or more than two hospitals and had been misdiagnosed as other diseases or failed to get a clear diagnosis for 3 months and over before hospitalization were included in the group of clinical misdiagnosis or the group without a definite diagnosis. Relevant data were analyzed. RESULTS: 516 cases (51.04%) were misdiagnosed, 193 cases (19.09%) failed to be diagnosed as a specific disease, only 302 cases (29.87%) had been diagnosed as HLD within 3 months after the onset. The 516 cases had been misdiagnosed as more than 100 different diseases, including all types of hepatitis, cirrhosis, splenomegaly, hepatomegaly, arthritis, nephritis, encephalitis, encephalopathy, psychosis, anaemia, and so on. The curative effect was much better in the group with early diagnosis than in the groups with misdiagnosis and without a clear diagnosis (P < 0.01). CONCLUSION: HLD is often misdiagnosed as other diseases or fails to get a clear diagnosis. Early diagnosis and treatment without delay is critical to the prognosis. Patients with symptoms described in this article should be examined for the presence of corneal K-F ring and copper metabolism teat should be made when necessary.

Adolescent↗