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Biomedical subjects

H He

Publications and source records attributed to H He.

At least 91 records · Page 5Linked to original sources
PubMed2000

Transforming growth factor-alpha, epidermal growth factor receptor, and PCNA immunoexpression in uterine leiomyosarcomas and leiomyomas in B6C3F1 mice.

The role of growth factors in the development of murine uterine mesenchymal tumors is unknown. In this study, immunohistochemical expression of transforming growth factor alpha (TGF-alpha) and its receptor epidermal growth factor (EGF-R) was assessed in spontaneous uterine leiomyomas and leiomyosarcomas in B6C3F1 mice. Cell proliferation, which has been induced by some growth factors, was evaluated by immunohistochemical detection of an endogenous marker of cell proliferation, proliferating cell nuclear antigen (PCNA). PCNA labeling indices were determined and compared to the intensity and distribution of TGF-alpha staining in sequential sections of control myometrium or tumor tissue. Results showed uterine leiomyosarcomas had positive cytoplasmic staining for TGF-alpha; however, all uterine leiomyomas evaluated were negative. Positive EGF-R staining was also observed in the uterine leiomyosarcomas, but not in the leiomyomas. EGF-R immunoexpression was detected primarily within the cytoplasm of the leiomyosarcoma cells, with occasional nuclear immunoreactivity. Immunohistochemical staining for PCNA was more intense and there were increased numbers of positively staining nuclei in the leiomyosarcomas compared to samples of control myometrium or leiomyomas. The mean labeling index for the uterine leiomyosarcomas (7.40%) was significantly (p < 0.01) higher than that of leiomyomas (0.29%) and control uterine myometrium (0.13%). We conclude, that TGF-alpha and its receptor, EGF-R, are expressed more intensely in uterine leiomyosarcomas, compared to leiomyomas in B6C3F1 mice. Immunoexpression of TGF-alpha may be an important biomarker of malignancy in uterine smooth muscle tumors in mice. Futhermore, TGF-alpha may play a critical role in increased proliferation of uterine smooth muscle tumor cells as suggested by increased immunolocalization of PCNA in rodent leiomyosarcomas expressing TGF-alpha, although other factors regulating cell replication can not be ruled out.

Animals↗
PubMed2000

Identification of a point mutation in an esterase gene in different populations of the southern cattle tick, Boophilus microplus.

Two esterase cDNA sequences were obtained from susceptible and organophosphorus resistant strains of Boophilus microplus. Both sequences have a high degree of homology to carboxylesterase B. One gene has identical sequences in both strains and the other showed two point mutations. One mutation produces an amino acid substitution when the amino acid sequence is deduced, this mutation was detected in six different populations susceptible and resistant to insecticides, but a pyrethroid resistant strain was the only one that showed only the mutant allele. Identification of this mutation and the strong signal detected in southern blot with this strain, suggest that esterases are contributing to detoxification of pyrethroid compounds, as a resistant mechanism in Mexican strains of the southern cattle tick.

Amino Acid Sequence↗
PubMed2000

Cloning and transcriptional expression of a leucokinin-like peptide receptor from the southern cattle tick, Boophilus microplus (Acari: Ixodidae).

Leucokinins are invertebrate neuropeptides that exhibit myotropic and diuretic activity. Only one leucokinin-like peptide receptor is known, the lymnokinin receptor from the mollusc Lymnaea stagnalis. A cDNA encoding a leucokinin-like peptide receptor was cloned from the Southern cattle tick, Boophilus microplus, a pest of cattle world-wide. This is the first neuropeptide receptor known from the Acari and the second known in the subfamily of leucokinin-like peptide G-protein-coupled receptors. The deduced amino acid sequence exhibits 40% identity to the lymnokinin receptor. The receptor transcript is present in all tick life stages as determined by semiquantitative reverse transcription polymerase chain reaction. We also propose that the sequence AAF50775.1 from the Drosophila melanogaster genome (CG10626) encodes the first identified insect leucokinin receptor.

Amino Acid Sequence↗
PubMed2000

Children at risk for asthma: home allergen levels, lymphocyte proliferation, and wheeze.

BACKGROUND: Allergic asthma is a common childhood disease. Although T-lymphocyte activation plays a critical role in allergic asthma, the environmental factors promoting lymphocyte activation in children are not well defined. OBJECTIVE: In a cohort of children at risk for asthma (n = 114), we determined whether the levels of cockroach (Bla g 1 or 2), house dust mite (Der f 1), and cat allergen (Fel d 1) in the home during infancy was associated with subsequent allergen-specific lymphocyte proliferation in later life. METHODS: Dust samples from multiple sites in the home were collected at 3 months of age and were measured for allergen levels. Serial questionnaires were applied. At a median age of 2 years, PBMCs were isolated and lymphocyte proliferation to the home allergens and PHA was determined. RESULTS: Increased lymphocyte proliferative responses to Bla g 2 were associated with higher home levels of Bla g 1 or 2 (P for trend with kitchen Bla g levels =.011), in analyses adjusting for cold in the past week. Proliferative responses to Der f 1 were higher in homes with family room levels of Der f 1 > or =10 microg/g dust than in homes with Der f 1 <2 microg/g, but differences were not significant in analyses adjusting for cold (P =. 15). Repeated wheeze in the first 2 years of life was associated with increased allergen-specific and PHA proliferative responses. CONCLUSION: Early-life cockroach allergen exposure at 3 months of age predicts allergen-specific lymphocyte proliferative responses at a median of 2 years of age.

Air Pollution, Indoor↗
PubMed2000

Increased drug delivery to the brain by P-glycoprotein inhibition.

BACKGROUND: Although the antidiarrheal loperamide is a potent opiate, it does not produce opioid central nervous system effects at usual doses in patients. On the basis of in vitro studies demonstrating that loperamide is a substrate for the adenosine triphosphate-dependent efflux membrane transporter P-glycoprotein, we postulated that inhibition of P-glycoprotein with quinidine would increase entry of loperamide into the central nervous system with resultant respiratory depression. METHODS: To test this hypothesis, a 16-mg dose of loperamide was administered to eight healthy male volunteers in the presence of either 600 mg quinidine, a known inhibitor of P-glycoprotein, or placebo. Central nervous system effects were measured by evaluation of the respiratory response to carbon dioxide rebreathing as a measure of opiate-induced respiratory depression. RESULTS: Loperamide produced no respiratory depression when administered alone, but respiratory depression occurred when loperamide (16 mg) was given with quinidine at a dose of 600 mg (P < .001). These changes were not explained by increased plasma loperamide concentrations. CONCLUSION: This study therefore demonstrates first the potential for important drug interactions to occur by a new mechanism, namely, inhibition of P-glycoprotein, and second that the lack of respiratory depression produced by loperamide, which allows it to be safely used therapeutically, can be reversed by a drug causing P-glycoprotein inhibition, resulting in serious toxic and abuse potential.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2000

Phenotypic characterization of the Xenorhabdus bacterial symbiont of a Texas strain of the entomopathogenic nematode Steinernema riobrave, and characterization of the Xenorhabdus bovienii bacterial symbiont of a Newfoundland strain of Steinernema feltiae.

Two bacterial symbionts of entomopathogenic nematodes, one of which originated from Texas, U.S.A., and the other from Newfoundland, Canada, were characterized phenotypically. These strains belonged to the genus Xenorhabdus. The Newfoundland (NF) strain was shown to be X. bovienii but the Texas (TX) strain was not identified at the species level. Four additional cultures of Xenorhabdus were included in the study. These were a strain of X. bovienii (Umeå), which was from a nematode of European origin, and strains of X. nematophilus, X. beddingii, and X. poinarii. The tests used in this study indicated identical properties for the NF (North American) and Umeå (European) strains of X. bovienii. These could be differentiated from the other strains studied by their failure to grow at 34 degrees C and resistance to low concentrations of a mixture of amoxilline and clavulanic acid. The Xenorhabdus TX strain could be differentiated from the other strains studied by its failure to grow at 10 degrees C. Of the tests done, approximately 30 were useful in distinguishing between the strains and species studied.

Animals↗
PubMed2000

Immunohistochemical localization of growth factors and their receptors in uterine leiomyomas and matched myometrium.

Immunolocalization of transforming growth factor alpha (TGF-Alpha), epidermal growth factor (EGF), insulinlike growth factor (IGF)-I, vascular endothelial growth factor (VEGF(165,189,121)), basic fibroblast growth factor (FGF)-2, EGF receptor (R), IGF-IRbeta, and FGFR-1 was studied in uterine leiomyomas and matched myometrial samples taken from seven women (42-47 years of age) in the proliferative phase of the menstrual cycle. Immunolocalization of growth factor peptides was accomplished with either monoclonal or polyclonal antibodies to the amino or carboxy terminus of growth factor peptides or their respective receptors, or against full-length recombinant growth factor. All reactions were conducted using the avidin-biotin complex method. Immunolocalization of TGF-alpha, EGF, EGF-R, IGF-I, IGF-IRbeta, FGF-2, FGFR-1, and VEGF was observed in the cytoplasm of smooth-muscle cells of leiomyomas and matched myometrium. The cytoplasm of vascular smooth-muscle cells expressed TGF-alpha, EGF, EGF-R, IGF-I, IGF-IRbeta, FGF-2, FGFR-1, and VEGF, whereas the vascular endothelium was positive for TGF-alpha, EGF, EGF-R, FGF-2, and FGFR-1 in both leiomyomas and matched myometria. Fibroblasts within the fibrous component of some leiomyomas were positive for IGF-I and FGF-2 and minimally positive for FGFR-1. In addition, the extracellular matrix of leiomyomas showed focal localization of FGF-2 and IGF-I in some tumors. When scores of intensity and percent positive staining were compared, IGF-IRbeta was significantly increased in the leiomyomas compared to matched myometria, whereas EGF was significantly decreased in the uterine leiomyomas compared to matched myometria. In summary, these data revealed growth factors to be expressed differentially in smooth muscle, vascular and fibroblastic cell types of leiomyomas and matched myometria. Specifically, IGF-IRbeta was significantly increased in leiomyomas; although a similar increase was seen with IGF-I peptide, statistical significance was not achieved. The EGF peptide was significantly decreased in the leiomyomas compared to matched myometrium. These data suggest that IGF-IRbeta and IGF-I peptide may be one of several growth factor/receptor pathways important in uterine leiomyoma growth during the proliferative phase of the menstrual cycle. In addition, decreased EGF may be secondary to the predominant estrogenic milieu present at time of sampling, as it has been proposed that progesterone, and not estrogen, may regulate EGF.

Adult↗
PubMed2000

HSP70 and heat shock factor 1 cooperate to repress Ras-induced transcriptional activation of the c-fos gene.

Heat shock protein 70 (HSP70) is a molecular chaperone involved in protein folding and resistance to the deleterious effects of stress. Here we show that HSP70 suppresses transcription of c-fos, an early response gene that is a key component of the ubiquitous AP-1 transcription factor complex. HSP70 repressed Ras-induced c-fos transcription only in the presence of functional heat shock factor1 (HSF1). This suggests that HSP70 functions as a corepressor with HSF1 to inhibit c-fos gene transcription. Therefore, besides its known function in the stress response, HSP70 also has the property of a corepressor and combines with HSF1 to antagonize Fos expression and may thus impact multiple aspects of cell regulation.

Animals↗
PubMed2000

[Electron spin resonance studies on inhibiting methemoglobin in erythrocyte with exogenous ascorbic acid].

Research on inhibiting the methemoglobin (MetHb) in erythrocyte by means of exogenous ascorbic acid is helpful to elucidating whether exogenous antioxidant inhibits the oxidative denaturation of hemoglobin when the erythrocyte does not inhibit such denaturation with its own antioxidation system. Using electron spin resonance (ESR) technique, we have studied the oxidative denaturation of hemoglobin and the inhibition of MetHb in erythrocyte with the exogenous ascorbic acid. The results indicate that there is the ESR absorption of high spin MetHb (g = 6) at the 5th, 35th and 90th min after the blood was mixed with NaNO2. The ESR absorption of high spin MetHb increases with time. Yet, in the case where the blood was mixed with exogenous ascorbic acid in advance, the ESR absortpion of high spin MetHb (g = 6) only appears at the 35th min among the ESR measures at the 5th, 35th, and 90th min after the blood was mixed with NaNO2. These findings suggest that exogenous antioxidant can inhibit the oxidative denaturation of hemoglobin when the erythrocyte does not inhibit such dematuration with its own antioxidation system.

Adult↗
PubMed2000

Fusion of low-fusing porcelain to Ti-75 alloy: an experimental study.

OBJECTIVE: To study the stomatological feasibility of low-fusing porcelain fused to Ti-75 alloy. METHODS: Electroprobemicroanalysis (EPMA) and shear test were used to observe interface state and bonding strength of porcelaintitanium. RESULTS: Shear bond strengths of low-fusing porcelain with Ti-75 alloy and conventional porcelain each fused to metal (NC-VMK68) were 47.38 +/- 7.95 MPa and 48.50 +/- 7.60 MPa, respectively. There was no significant difference between the shear bonding strength of low-fusing porcelain with Ti-75 and that of conventional porcelain fused to metal (PFM) (P > 0.05). EPMA showed that Ti-75 alloy and low-fusing porcelain bound tightly, had no fissure, and that low-fusing porcelain had good infiltration to Ti-75. It was shown that Ti spread from Ti-75 basal body into porcelain, and elements such as Si-Sn spread from porcelain to Ti-75. CONCLUSION: Ti-75 alloy can be used stomatologically, as a porcelain alloy.

Biocompatible Materials↗
PubMed2000

Analysis of the mandibular position in malocclusion patients.

OBJECTIVE: To study the changes of condyle position and occlusion between centric jaw relation (CR) and maximum intercuspation (MI) positions. METHODS: The power centric registration advocated by Roth was used to take centric relation bite registration for 50 patients (25 Angle Class I, and 25 Angle Class II). Diagnostic models were mounted and analyzed with Panadent articulator and condylar position indicator. RESULTS: Nearly all patients had CR-MI difference in all three spatial planes. Seventy percent of the sagittal displacement was within 2.0 mm and 87% of the transverse displacement was within 1.0 mm. Movement of most of the condyles was posterior and inferior. Sixty-five percent of the initial contacts in CR occurred on the most posterior molar on one side. When the mandible moved from CR to MI, overbite deepened, overjet decreased, and molar relationship became mesialized. Correlation was found between some variables of condylar displacement and occlusion changes. No significant difference between Angle Class I and Angle Class II patients was observed in condylar position and occlusion changes. CONCLUSION: The occlusion in centric jaw relation should be analyzed before treatment to reveal the disharmony between occlusion and jaw position.

Adolescent↗
PubMed2000

Effects of Scutellarein on diabetic rat aorta.

AIM: To study the effect of Scutellarein (Scu) on the diabetic rat aorta. METHODS: Contractile responses to phenylepherine and endothelium-dependent relaxation responses to acetylcholine (ACh) in rat aorta were investigated after streptozocin-induced 6-wk diabetes, Scu-treated streptozocin-induced diabetes, and in age-matched control in vitro. RESULTS: 1) Endothelium-dependent relaxation to ACh in diabetic rats was decreased (P < 0.01) compared with age-matched control. 2) Contractile responses to phenylepherine were increased (P < 0.01) in diabetic rats. 3) The dietary supplement of 0.5% Scu starting from 1-wk diabetes induction prevented endothelial dysfunction (P < 0.01), but the contractile responses to phenylepherine were further increased. CONCLUSION: Scu prevented vascular endothelial dysfunction in diabetic rats, and also potentiated the contraction induced by phenylepherine.

Animals↗
PubMed2000

[Cloning and primary analysis of 3 'end genome of two alphaviruses isolated from Hainan Province of China].

OBJECTIVE: To further characterize the HBbl7 and Ml viruses isolated from Hainan Province by molecular biology. METHODS: The fragment containing partial El and 3'untranslated region of each of the viral isolate was amplified by RT-PCR, then subcloned. Recombinant was screened and sequenced. Analysis and comparison were carried out. RESULTS: 1.6kb fragment was amplified from HBbl7 and a 1.3kb was from Ml Comparison of sequences showed, in 3'untranslated region the nucleotide homology between HBbl7 and T48, the prototype of Ross River virus, is 99%, between Ml and Sagiyama virus is 98%. In the partial El sequence, the nucleotide (amino acid) homology between HBbl7 and T48 is 99%(99%),between Ml and Sagiyama virus is 97%(99%), and between Ml and Cetah virus is 94% (98%). CONCLUSIONS: Sequence analysis showed HBb17 virus belongs to Ross River virus, Ml virus belongs to Sagiyama virus or Cetah virus.

Alphavirus↗
PubMed2000

[Effect of different watering and fertilization on N utilization efficiency].

The comprehensive effects of the timing of watering and N and K fertilization(D), amount of irrigated water(W), and application rates of chemical N and K fertilizers, and farm manure(M) were studied by the design of orthogonal regression rotation with five factors and five levels under dry greenhouse condition. The N utilization efficiency of potato was in order of N > W > D > M > K. Under different application rates of W, N, K and M, the N utilization efficiency was significantly increased with optimum timing of watering and fertilization. When the application rate was low, the timing should be earlier, while it was high, the timing should be later. High application rates of W and N resulted in the best interaction effect, with 57.83% of N utilization efficiency; moderater W and N or low W and N had 29.17-40.99% of efficiency; and high W and low N or low W and high N resulted in the lowest efficiency, with 22.87% and 22.51%, respectively.

Fertilizers↗
PubMed2000

[WHO sample survey on drug resistant tuberculosis in Zhejiang, China].

OBJECTIVES: To obtain the data on initial and acquired drug resistance, and to evaluate the efficacy of ongoing tuberculosis (TB) control strategies. METHODS: According to the Guidelines for Surveillance of Drug Resistance in Tuberculosis of WHO/IUATLD, randomly selected 30 counties with population proportionate cluster sampling method. Proportion method was used for drug sensitivity test, laboratory quality control was done by Korean super-country reference laboratory. RESULTS: 1,013 TB patients were enrolled in 30 counties, 954 were culture positive, and one with non-tuberculous mycobacteria. The culture positive rate was 94.6%, the contaminated rate was 3.2%. Drug susceptibility testing against streptomycin (SM), isoniazid (INH), rifampicin (RFP) and ethambutol (EMB) were performed in 953 cases, the total drug resistant rate was 21.5%, the initial drug resistant rate was 14.8%, the initial multi-drug resistance was 4.4%, the acquired drug and multi-drug resistant rates were 59.0% and 34.7%, respectively. CONCLUSIONS: The initial drug resistant rates were decreasing in comparison to 1990 (24.0%), suggesting good effect of DOTS policy implemented in Zhejiang province. However, multi-drug resistant rate was higher in this province than some other countries, indicating more attention should be paid to this situation.

Anti-Bacterial Agents↗