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Biomedical subjects

T He

Publications and source records attributed to T He.

At least 73 records · Page 4Linked to original sources
PubMed1998

Chemokine coreceptor usage by diverse primary isolates of human immunodeficiency virus type 1.

We tested chemokine receptor subset usage by diverse, well-characterized primary viruses isolated from peripheral blood by monitoring viral replication with CCR1, CCR2b, CCR3, CCR5, and CXCR4 U87MG.CD4 transformed cell lines and STRL33/BONZO/TYMSTR and GPR15/BOB HOS.CD4 transformed cell lines. Primary viruses were isolated from 79 men with confirmed human immunodeficiency virus type 1 (HIV-1) infection from the Chicago component of the Multicenter AIDS Cohort Study at interval time points. Thirty-five additional well-characterized primary viruses representing HIV-1 group M subtypes A, B, C, D, and E and group O and three primary simian immunodeficiency virus (SIV) isolates were also used for these studies. The restricted use of the CCR5 chemokine receptor for viral entry was associated with infection by a virus having a non-syncytium-inducing phenotype and correlated with a reduced rate of disease progression and a prolonged disease-free interval. Conversely, broadening chemokine receptor usage from CCR5 to both CCR5 and CXCR4 was associated with infection by a virus having a syncytium-inducing phenotype and correlated with a faster rate of CD4 T-cell decline and progression of disease. We also observed a greater tendency for infection with a virus having a syncytium-inducing phenotype in men heterozygous for the defective CCR5 Delta32 allele (25%) than in those men homozygous for the wild-type CCR5 allele (6%) (P = 0.03). The propensity for infection with a virus having a syncytium-inducing phenotype provides a partial explanation for the rapid disease progression among some men heterozygous for the defective CCR5 Delta32 allele. Furthermore, we did not identify any primary viruses that used CCR3 as an entry cofactor, despite this CC chemokine receptor being expressed on the cell surface at a level commensurate with or higher than that observed for primary peripheral blood mononuclear cells. Whereas isolates of primary viruses of SIV also used STRL33/BONZO/TYMSTR and GPR15/BOB, no primary isolates of HIV-1 used these particular chemokine receptor-like orphan molecules as entry cofactors, suggesting a limited contribution of these other chemokine receptors to viral evolution. Thus, despite the number of chemokine receptors implicated in viral entry, CCR5 and CXCR4 are likely to be the physiologically relevant chemokine receptors used as entry cofactors in vivo by diverse strains of primary viruses isolated from blood.

Animals↗
PubMed1998

In vivo distribution of the human immunodeficiency virus/simian immunodeficiency virus coreceptors: CXCR4, CCR3, and CCR5.

We have evaluated the in vivo distribution of the major human immunodeficiency virus/simian immunodeficiency virus (HIV/SIV) coreceptors, CXCR4, CCR3, and CCR5, in both rhesus macaques and humans. T lymphocytes and macrophages in both lymphoid and nonlymphoid tissues are the major cell populations expressing HIV/SIV coreceptors, reaffirming that these cells are the major targets of HIV/SIV infection in vivo. In lymphoid tissues such as the lymph node and the thymus, approximately 1 to 10% of the T lymphocytes and macrophages are coreceptor positive. However, coreceptor expression was not detected on follicular dendritic cells (FDC) in lymph nodes, suggesting that the ability of FDC to trap extracellular virions is unlikely to be mediated by a coreceptor-specific mechanism. In the thymus, a large number of immature and mature T lymphocytes express CXCR4, which may render these cells susceptible to infection by syncytium-inducing viral variants that use this coreceptor for entry. In addition, various degrees of coreceptor expression are found among different tissues and also among different cells within the same tissues. Coreceptor-positive cells are more frequently identified in the colon than in the rectum and more frequently identified in the cervix than in the vagina, suggesting that the expression levels of coreceptors are differentially regulated at different anatomic sites. Furthermore, extremely high levels of CXCR4 and CCR3 expression are found on the neurons from both the central and peripheral nervous systems. These findings may be helpful in understanding certain aspects of HIV and SIV pathogenesis and transmission.

Animals↗
PubMed1998

Genotypic characterization of Actinobacillus actinomycetemcomitans isolated from periodontitis patients by arbitrarily primed polymerase chain reaction.

Actinobacillus actinomycetemcomitans is one of the most suspected pathogens in the initiation and progression of juvenile periodontitis and severe adult periodontitis. The aim of the present study was to investigate the genotypic characterization of A. actinomycetemcomitans using arbitrarily primed polymerase chain reaction (AP-PCR). AP-PCR was applied to 143 A. actinomycetemcomitans strains, including 8 reference strains and 135 clinical strains isolated from 43 unrelated Japanese periodontitis patients. The DNA fragment patterns obtained using a single 10-mer primer with random sequence (OPA-07) for these strains allowed the recognition of 10 distinct AP-PCR groups that correlated to some extent with serotypes. AP-PCR group VIII was significantly (P < 0.05) observed in deep (> 5 mm) periodontal pockets. Group II was exclusively detected in deep pockets. However, a clear relationship was not observed between AP-PCR genotypes and various periodontal status. Only one genotype was found within individual oral cavity/single-infected site, except one case in which the patient harbored two AP-PCR genotypes. The AP-PCR patterns of the A. actinomycetemcomitans isolates recovered from the site after periodontal treatment remained identical. These results demonstrate genetic diversity among the investigated population and a clonal nature in a periodontal patient of A. actinomycetemcomitans by AP-PCR. Furthermore, it could be inferred that a certain AP-PCR genotype(s) of A. actinomycetemcomitans is more important in the pathogenesis of periodontal diseases.

Adolescent↗
PubMed1998

In vivo and in vitro studies on the antitumor activities of MCP (Malva crispa L. Powder).

Four short-term in vivo and in vitro tests were used to further confirm the antitumor activities of MCP, a vegetable powder, prepared from Malva crispa L. (i) In the H22 hepatoma-transplanting test, MCP had antitumor action, but MCP residue did not show such action; 5-FU appeared to have more potent antitumor activities and more harmful effects than MCP. (ii) In the micronucleus (MN) test, MCP significantly decreased MN frequency. (iii) In the cancer cell culture systems, the MCP fat-soluble extract revealed inhibitory effects on the growth and proliferation of the human hepatoma and the gastric cancer cells in a dose-response manner. (iv) In the colony formation test, MCP also altered the morphology of human gastric cancer cells. It was suggested that MCP could be consumed not only by healthy subjects for cancer prevention but also by patients with cancer as supplementary treatment in combination with anticarcinogenic drug such as 5-FU, cyclophosphamide (CP).

Animals↗
PubMed1998

[Respiratory muscle function and serum enzymology in hyperthyroidism before and after treatment].

To investigate the effect of hyperthyroidism on respiratory muscle function and its possible mechanism, the thyroid function, serum enzymology, serum potassium, pulmonary function and respiratory muscle function were examined in 60 patients with Grave's disease before treatment and 26 patients among them after treatment, and 20 normal subjects as control. T3, T4, and FT4 increased while FVC and PImax, which reflect the respiratory muscle strength, and Pi/PImax, which reflects the reserve capacity of inspiratory muscle, decreased significantly in the 60 patients with Grave's disease, compared with the ones of normal subjects. The comparison of above measurements in the 26 patients between before- and after-treatment showed that respiratory muscle strength increased obviously along with the improvement of throid function. The serum enzymology, potassium and TSH, however, were not abnormal and not changed after treatment. The thyroid functions in 10 patients with hyperthyroid heart disease were not different, compared with the ones of other 50 patients without hyperthyroid heart disease, but their respiratory muscle strength was significantly lower than the ones of latter. The above results suggested that hyperthyroidism could lead to significant decrease of respiratory muscle strength and its reserve capacity, whereas treatment for hyperthyroidism would improve respiratory muscle function, so the measurement of respiratory muscle function in hyperthyroidism cases might be useful in prediction of hyperthyroid heart disease.

Adult↗
PubMed1998

[Study on enzyme-linked immunosorbent assay for cholecystokinin].

This study was undertaken to develop a method for assaying octapeptide cholecystokinin (CCK-8) using ELISA. The design of the method was based on the pretreatment of polystyrene microplates with ultraviolet irradiation and glutaraldehyde activation piror to coating. The results showed that this pretreatment let to stable attachment of CCK-8 to the solid-phase. Competitive ELISA with CCK-8 as a competitor gave excellent quantitive relationship. Using this method we distinguished two kinds of CCK-related peptides. This method proved to be simple, stable and reproducible, the intra- and inter-assay coefficients of variation were 4.75% and 7.80% respectively.

Animals↗
PubMed1998

[Microvasculature of the dog's periodontal ligament and its immediate response to orthodontic forces].

The purpose of this study was to examine the microvascular architecture of dog's periodontal ligament (PDL) and its immediate response to horizontal orthodontic force. A force of 200 g was applied mesially to the mandibular premolar of a dog for 2 hours, the distal side served as the contrast side. Formalin ink was perfused into the carotid arteries bilaterally through the cannulas. After perfusion the mandible was decalcified, celloidin embedded, serially sectioned and stained with eosin. The sections were then observed by light microscope and analyzed by image analyzer. Vascular corrosion casts were prepared by the similar way with the formalin ink perfusion and examined by scanning electron microscope. The results showed: there were extensive interconnections among the PDL, dental pulp, gingiva, alveolus and the neighbour tooth PDL, which would benefit the maintenance of health and functions of the dental pulp and the periodontal tissues. Arterioles and venulae could be confirmed by the presence of characteristic differences of nuclear impressions in endothelial cell under the scanning electron microscope. The quantitative analysis showed that the tensioned PDL sites in the experimental group had a higher microvascular volume density than the corresponding sites in the contrast group, while the pressed PDL sites in the experimental group had a lower microvascular volume density than the corresponding sites in the contrast group. This should result from the hydraulic mechanism in the PDL.

Animals↗
PubMed1998

Stent revascularization for atherosclerotic renal artery stenosis. 1-year clinical follow-up.

Patients who had undergone stent revascularization of renal artery stenosis for poorly controlled hypertension, preservation of renal function, or both were monitored to assess the procedure's effect upon subsequent renal function and blood pressure control. At 1-year follow-up, systolic and diastolic blood pressures had significantly decreased (166 +/- 26 to 156 +/- 25 mmHg and 86 +/- 14 to 80 +/- 13 mmHg, respectively; P < 0.05), and creatinine levels decreased or remained stable in approximately two thirds of the patients. Renal artery stent revascularization appears to have a beneficial effect upon blood pressure control and a nondeleterious effect upon renal function in the majority of patients.

Aged↗
PubMed1998

Wavelet-assisted volume ray casting.

Volume rendering is an important technique for computational biology. In this paper we propose a new wavelet-assisted volume ray casting algorithm. The main idea is to use the wavelet coefficients for detecting the local frequency, and decide the appropriate sampling rate along the ray according to the maximum frequency. Our algorithm is to first apply the 3D discrete wavelet transform on the volume, then create an index volume to indicate the necessary sampling distance at each voxel. During ray casting, the original volume is traversed in the spatial domain, while the index volume is used to decide the appropriate sampling distance. We demonstrate that our algorithm provides a framework for approximating the volume rendering at different levels of quality in a rapid and controlled way.

Algorithms↗
PubMed1997

HIV type 1 subtypes, coreceptor usage, and CCR5 polymorphism.

Identification of the chemokine receptors CCR5 and CXCR4 as the major coreceptors for HIV-1 entry has greatly assisted our understanding of HIV-1 pathogenesis, transmission, and tropism. However, most of our current knowledge on coreceptor usage comes from studies using HIV-1 strains or env genes derived from the genetic subtype B predominant in North America and western Europe. In this report, the coreceptor usage of 20 primary viral isolates representative of genetic subtypes A, B, C, D, E, and group O was examined. Thirty-nine full-length CCR5 sequences from individuals of diverse geographic origins were also obtained to examine the possible effect of CCR5 polymorphism on HIV-1 subtype distribution. Our results indicate that (1) CCR5 and CXCR4 serve as the two major coreceptors for viruses belonging to HIV-1 subtypes A, B, C, D, E, and group O, whereas other chemokine receptors such as CCR2b and CCR3 play only a minor role in facilitating viral entry into stimulated PBMCs; (2) the coreceptor usage is determined by the viral phenotype rather than its genotype because all NSI strains, irrespective of their subtype classification, utilize CCR5, whereas all SI strains are able to use CXCR4; and (3) there is no geographic clustering of CCR5 polymorphism in different ethnic populations, suggesting that CCR5 diversity is not the underlying explanation for differences in the spread of different HIV-1 subtypes. Therefore, the uneven worldwide distribution of HIV-1 subtypes is more likely the result of stochastic dissemination.

Amino Acid Sequence↗
PubMed1997

Expectancy of working life of mine workers in Hunan province.

From demographic mortality and disability of, in total, 424965 y from workers in 29 coal or coloured/metal mines in Human province of China during the period 1980-1984, we calculated the length of expected working life (EWL) as well as the life expectancy (EL) of the workers in the different types of mines and between those working on the surface and those working underground. The average life expectancy in the coal mines for those starting work at 15 y was found to be 58.91 y and 49.23 y for surface and underground workers respectively. In the coloured/metal mines they were 60.24 y and 56.55 y respectively. If only the mortality data was taken into account; for the coal mines, the EWL at the age of 15 y of surface workers and underground workers was 48.46 and 45.10 y respectively; whilst in the coloured/metal mines the figures were 48.25 and 45.99 y respectively. If both mortality and morbidity data is used the EWL at the same age and in the same population is for the coal mines 39.42 (surface workers) 25.54 (underground workers) and for the coloured/metal mines 42.05 (surface workers) and 30.02 (underground workers). The main causes of the lowered EWL of the underground workers were industrial accidents and pneumoconiosis which indicates that safety measures need to be increased and working conditions improved to protect underground workers.

Accidents, Occupational↗
PubMed1997

Prevalence of Actinobacillus actinomycetemcomitans serotypes in Japanese patients with periodontitis.

Oral Actinobacillus actinomycetemcomitans strains are serologically classified into 5 distinct groups, a to e. We examined the distribution of A. actinomycetemcomitans serotypes in Japanese patients with periodontitis. A total of 157 A. actinomycetemcomitans clinical isolates from diseased sites of 39 patients with periodontitis were serotyped by using serotype-specific rabbit antisera against A. actinomycetemcomitans serotypes a, b, c, d and e strains. In the immunodiffusion assay, autoclaved extracts of 42, 6, 39, 9 and 41 A. actinomycetemcomitans clinical isolates reacted with serotypes a, b, c, d and e antisera, respectively. Although 37 patients were infected with a serotype strain, 2 patients harbored 2 different serotype strains, b/e and b/untypeable. To establish a correlation between serotype and genotype of A. actinomycetemcomitans clinical isolates from 2 patients who had different serotype strains, we used arbitrarily primed polymerase chain reaction (AP-PCR) to fingerprint clinical isolates of different serotypes. The AP-PCR genotypes among 4 clinical isolates (b/e and b/untypeable) were identical to that of A. actinomycetemcomitans Y4 (serotype b), indicating the presence of multiple A. actinomycetemcomitans serotypes which are genetically homogeneous in the periodontally diseased sites of patients with periodontitis.

Actinobacillus Infections↗
PubMed1997

[Measurement and clinical significance of inspiratory drive efficacy in patients with chronic obstructive pulmonary disease].

To study the relationship between VT/P0.1 and the function of inspiratory muscles, we performed the measurement of VT/P0.1 (inspiratory drive efficacy), MIP (maximal inspiratory mouth pressure) and MMIF (maximal midinspiratory flow) in 15 normal subjects and 60 patients with chronic obstructive pulmonary disease(COPD). The results indicated that VT/P0.1 decreased with the deterioration of COPD and it correlated highly and positively with MIP and MMIF. These suggest that VT/P0.1 can reflect the function of inspiratory muscles as well as MIP and MMIF can.

Aged↗
PubMed1997

[Effect of methylphenidatum on inspiratory muscles function in patients with chronic obstructive pulmonary disease and its mechanism].

To have a better understanding of the effect of methylphenidatum on inspiratory muscles function, we studied the respiratory force parameters of 70 patients with chronic obstructive pulmonary disease by intravenous infusion methylphenidatum in a randomized controlled clinical trial. The indices of respiratory force parameter included maximal inspiratory mouth pressure (MIP), maximal midinspiratory flow (MMIF), forced inspiratory capacity (FIC), maximal works of inspiration (Wimax) and airway occlusion pressure (P0.1), etc. Aminophylline and Nikethamidi were chosen as controls. The results showed that MIP, MMIF, FIC, Wimax, P0.1 and minute ventilation (Vr) were significantly increased after administration of methylphenidatum and aminophylline. There were no significant differences in MIP, MMIF, FIC and Wimax after administration of Nikethamidi, but P0.1 was significantly increased and the increase was higher than that after administration of methylphenidatum and aminophylline groups. We conclude that methylphenidatum can significantly improve the function of inspiratory muscles as aminophylline can do.

Female↗
PubMed1997

[Measuring EEG complexity for studying the state of mental load].

The complexity defined by Lemple and Ziv (1976) represents the degree of the sequence randomness. In this paper, the complexity of EEG under different mental loads was measured and the relation between the brain active state and the EEG complexity was analyzed. The results showed a statistically strong relation between the mental load and the EEG complexity. Further study showed that the heavier the mental load was the smaller the EEG complexity became. This correlation was especially apparent in the frontal lobe, and the complexity of EEG might be regarded as one of the parameters representing the functional state of the brain. The results indicate that EEG complexity represents the active state of brain in processing information, and the measurement of EEG complexity may provide a new path to the research in the advanced cognitive function of the human brain.

Adult↗
PubMed1996

Clinical results of computerized tomography-based simulation with laser patient marking.

PURPOSE: Accuracy of a patient treatment portal marking device and computerized tomography (CT) simulation have been clinically tested. METHODS AND MATERIALS: A CT-based simulator has been assembled based on a commercial CT scanner. This includes visualization software and a computer-controlled laser drawing device. This laser drawing device is used to transfer the setup, central axis, and/or radiation portals from the CT simulator to the patient for appropriate patient skin marking. A protocol for clinical testing is reported. Twenty-five prospectively, sequentially accessioned patients have been analyzed. RESULTS: The simulation process can be completed in an average time of 62 min. Under many cases, the treatment portals can be designed and the patient marked in one session. Mechanical accuracy of the system was found to be within +/- 1mm. The portal projection accuracy in clinical cases is observed to be better than +/- 1.2 mm. Operating costs are equivalent to the conventional simulation process it replaces. CONCLUSION: Computed tomography simulation is a clinical accurate substitute for conventional simulation when used with an appropriate patient marking system and digitally reconstructed radiographs. Personnel time spent in CT simulation is equivalent to time in conventional simulation.

Computer Simulation↗
PubMed1996

The role of a mutant CCR5 allele in HIV-1 transmission and disease progression.

A 32-nucleotide deletion (delta 32) within the beta-chemokine receptor 5 (CCR5) gene has been described in subjects who remain uninfected despite extensive exposure to HIV-1. This allele was found to be common in the Caucasian population with a frequency of 0.0808, but was not found in people of African or Asian ancestry. To determine its role in HIV-1 transmission and disease progression, we analyzed the CCRS genotype of 1252 homosexual men enrolled in the Chicago component of the Multicenter AIDS Cohort Study (MACS). No infected participant was found to be homozygous for the delta 32 allele, whereas 3.6% of at-risk but uninfected Caucasian participants were homozygous, showing the highly protective role of this genotype against sexual acquisition of HIV-1. No evidence was found to suggest that heterozygotes were protected against HIV-1 infection, but a limited protective role against disease progression was noted. The delta 32 allele of CCR5 is therefore an important host factor in HIV-1 transmission and pathogenesis.

Alleles↗