Biomedical subjects

L Shen

Publications and source records attributed to L Shen.

At least 181 records · Page 10Linked to original sources

PubMed1997

[Spectral analysis of R-R intervals in adolesent persons during mental stress].

In this study, power spectrum analysis of the autoregressive model was used to quantitatively estimate the power spectrum of R-R intervals in adolesent during the state of the mental stress. The power spectrum density of the lower frequency (HF: 0.05-0.15 Hz) and the high frequency (HF: 0.15-0.5 Hz) component were acquired. The results showed that during the mental stress the HF component decreased significantly (P < 0.001) while the LF component increased relatively and the center frequency of the HF increased remarkably (P < 0.001). This suggests that the spectral analysis of heart rate variability (R-R interval) offers an efficient non-invasive method to assess the autonomic nerve activity of cardiovascular system during the stress condition.

Adult↗

PubMed1997

[Clinical observation on effect of xiaoyu zhixue tablet on 104 patients with idiopathic multifocal bleeding and platelet aggregation defect].

OBJECTIVE: To explore the effect and pharmacological mechanism of Xiaoyu Zhixue Tablet (XZT). METHODS: The XZT mainly composed of Chinese medicinal herbs to replenishing Qi and removing stasis was used to treat patients with idiopathic multifocal bleeding and platelet aggregation defect. Patients were divided into 2 groups. The TCM group (104 cases) treated with XZT, and the control group (84 cases) treated with vitamins C, K and P, adrenosin and (or) artificial menstruation, for at least 4 months. RESULTS: The hemostatic effective rate was 92.3% in TCM group and 27.4% in control group (P < 0.005), the recovery rate of platelet aggregation after 6 months therapy was 69.2% and only 1.8% respectively. The difference between two groups was very significant (P < 0.005). CONCLUSION: XZT could regulate the physiological functions of blood-vessel and platelet to realize the hemostatic action and platelet aggregation.

Adolescent↗

PubMed1997

[Clinical significance of changes of fibrillation potential amplitude following denervation of human skeletal muscle].

To evaluate the value of clinical application of examination of fibrillation potential amplitude, 110 patients, 97 males and 13 females, were examined and only the maximum fibrillation potential amplitudes were recorded in 420 muscles. The results showed that there was no significant difference between sexes, ages and sides. However, significant difference was evident between the groups of different frequency (1+ to 4+). The fibrillation potential amplitude was maximum at 3 to 4 months after denervation and still remained at relatively high level for years in certain patients. No significant difference was showed between the time groups in incomplete nerve injuries. Surgery did not affect the course of fibrillation potential amplitude change. It was suggested that the muscle cells sustained their property for years after denervation in some patients, thus it might explain that satisfactory result could be obtained from operative repair in some late cases. The changes of fibrillation potential amplitude might indicate that the changes from muscle denervation was still reversible and might be more accurate than traditional method of examination.

Action Potentials↗

PubMed1997

[Intraoperative extra strong electrical stimulation in the treatment of peripheral nerve injury].

In order to enhance the therapeutic effectiveness of peripheral nerve injury, intraoperative extrastrong electrical stimulation was used in peripheral nerve surgery. In 16 cases of incomplete peripheral rnerve injuries or poorly regeneratedn erves, continuous intraoperative electrophysiological monitoring was used for guidance of neurolysis. Meanwhile, extrastong electrical stimulation was applied. The latency and amplitude before and after electrical stimulation were recorded and the extent of improrement was compared. In all cases, the latency and amplitude were improved after neurolysis and electrical stimulation. Clinical follow-up also showed that the function of corresponding innorvated muscle was improved. Continuous intraoperative extrastrong electrical stimulation could be used as an practical measure to increase the effectiveness of peripheral nerve treatment.

Adolescent↗

PubMed1996

Glu227-->Lys substitution in the acidic loop of major histocompatibility complex class I alpha 3 domain distinguishes low avidity CD8 coreceptor and avidity-enhanced CD8 accessory functions.

Cytotoxic T lymphocyte (CTL) activation requires specific T cell receptor (TCR)-class I major histocompatibility complex (MHC) antigen complex interactions as well as the participation of coreceptor or accessory molecules on the surface of CTL. CD8 can serve as a coreceptor in that it binds to the same MHC class I molecules as the TCR to facilitate efficient TCR signaling. In addition, CD8 can be "activated" by TCR stimulation to bind to class I molecules with high avidity, including class I not recognized by the TCR as antigenic complexes (non-antigen [Ag] class I), to augment CTL responses and thus serve an accessory molecule function. A Glu/Asp227-->Lys substitution in the class I alpha 3 domain acidic loop abrogates lysis of target cells expressing these mutant molecules by alloreactive CD8-dependent CTL. Lack of response is attributed to the destruction of the CD8 binding site in the alpha 3 domain which is likely to disrupt CD8 coreceptor function. The relative importance of the class I alpha 3 domain acidic loop Glu227 in coreceptor as opposed to accessory functions of CD8 is unclear. To address this issue, we examined CTL adhesion and degranulation in response to immobilized class I-peptide complexes formed in vitro from antigenic peptides and purified class I molecules containing wild-type or Glu227-->Lys substituted alpha 3 domains. The alpha 3 domain mutant class I-peptide complexes were bound by CTL and triggered degranulation, however to much lower levels than wild-type class I-peptide complexes. In further experiments, it is directly demonstrated that the alpha 3 domain mutant class I molecules, which lack the Glu227 CD8 binding site, still serve as TCR-activated, avidity-enhanced CD8 accessory ligands. However, mutant class I peptide Ag complexes failed to effectively serve as CD8 coreceptor ligands to initiate TCR-dependent signals required to induce avidity-enhanced CD8 binding to coimmobilized non-Ag class I molecules. Thus the Glu227-->Lys mutation effectively distinguishes CD8 coreceptor and avidity-enhanced CD8 accessory functions.

Binding Sites↗

PubMed1996

Type I (CD64) and type II (CD32) Fc gamma receptor-mediated phagocytosis by human blood dendritic cells.

Three classes of Fc receptors for IgG, Fc gamma RI (CD64), Fc gamma RII (CD32), and Fc gamma RIII (CD16), are expressed on blood leukocytes. Although Fc gamma R are important phagocytic receptors on phagocytes, most reports suggest that dendritic cells lack Fc gamma R-mediated phagocytosis and express significant levels of only CD32. We now report that phagocytically active forms of both CD64 and CD32 are expressed significantly on at least one subset of human blood dendritic cells. Countercurrent elutriation and magnetic bead selection were used to rapidly enrich subsets of blood dendritic cells (CD33brightCD14-HLA-DRbrightCD83-) and monocytes (CD33brightCD14brightHLA-DRdimCD83-). Upon culture for 2 days, dendritic cells became CD83-positive and markedly increased HLA-DR expression, whereas monocytes did not express CD83 and exhibited reduced levels of HLA-DR. Constitutive CD64 expression was identified on this circulating dendritic cell population, but at a lower level than on monocytes. CD64 expression by dendritic cells and monocytes did not decrease during 2 days in culture, and was up-regulated on both cell types following incubation with IFN-gamma. Freshly isolated blood dendritic cells performed CD64- and CD32-mediated phagocytosis, although at a lower level than monocytes. Dendritic cells generated by culture of adherent mononuclear cells in granulocyte-macrophage CSF and IL-4 also up-regulated CD64 following IFN-gamma stimulation, and mediated CD64-dependent phagocytosis. These results indicate that both CD64 and CD32 expressed on blood dendritic cells may play a role in uptake of foreign particles and macromolecules through a phagocytic mechanism before trafficking to T cell-reactive areas.

Cell Separation↗

PubMed1996

Defects in enteric innervation and kidney development in mice lacking GDNF.

Glial-lial-cell-line-derived neurotrophic factor (GDNF) has been isolated as neurotrophic factor for midbrain dopaminergic neurons. Because of its neurotrophic activity on a wide range of neuronal populations in vitro and in vivo, GDNF is being considered as a potential therapeutic agent for neuronal disorders. During mammalian development, it is expressed not only in the nervous system, but also very prominently in the metanephric kidney and the gastrointestinal tract, suggesting possible functions during organogenesis. We have investigated the role of GDNF during development by generating a null mutation in the murine GDNF locus, and found that mutant mice show kidney agenesis or dysgenesis and defective enteric innervation. We demonstrate that GDNF induces ureter bud formation and branching during metanephros development, and is essential for proper innervation of the gastrointestinal tract.

Animals↗

PubMed1996

Characterization of the gene encoding murine heparin-binding epidermal growth factor-like growth factor.

The mouse gene (mHB-EGF) encoding heparin-binding epidermal growth factor-like growth factor was isolated from a mouse 129SVJ genomic library. DNA sequence analysis confirmed that the clone contained six exons (I-VI) and five introns (A-E), and spanned approx. 14 kb of DNA. PCR analysis showed that introns A-E of mHB-EGF are 203 bp, 2.5 kb, 5.5 kb, 825 bp and 272 bp in length, respectively. These results establish that mHB-EGF is similar in organization to human HB-EGF (hHB-EGF). However, DNA sequence analysis of introns A-E of mHB-EGF failed to show significant overall homology with those of hHB-EGF.

Amino Acid Sequence↗

PubMed1996

Molecular cloning and characterization of a novel casein kinase II substrate, HASPP28, from rat brain.

HASPP28 (heat- and acid-stable phosphoprotein of 28 kDa) has been purified to near homogeneity from the acid-stable protein fraction of rat brain extract. Based on the N-terminal 40 amino acid sequence, a pair of highly degenerate primers was used to generate a 107-bp probe from rat brain RNA by RT-PCR. From the rat brain lambda gt11 library, this probe identified two positive clones that together provided a cDNA of 837 bp with an open reading frame of 546 bp. This cDNA was extended by 3'RACE to 1.2 kb that included a polyadenylation signal and a poly(A) tail. The 180-amino-acid sequence derived from the open reading frame, which did not correspond to any known protein, was predicted to have phosphorylation sites for protein kinase C, casein kinase II (CKII), and protein kinase A. Indeed, both the purified rat brain HASPP28 and the recombinant HASPP28 (rHASPP28) can be phosphorylated by these kinases. Northern blot analysis indicated that HASPP28 was present in all rat tissues tested, including those from the brain, lung, spleen, kidney, liver, heart, and muscle, in decreasing order of abundance. Phosphopeptide analysis of rHASPP28 phosphorylated in vitro by various kinases showed different tryptic patterns on two-dimensional mapping and isoelectric focusing gels. From [32P]PO4-labeled N1E115 neuroblastoma cells, HASPP28 can be immunoprecipitated with a polyclonal antiserum raised against rHASPP28. The immunoprecipitated protein showed a phosphopeptide pattern similar to that of rHASPP28 phosphorylated by CK II in vitro. Furthermore, the immunoprecipitates from cells treated with phorbol 12-myristate 13-acetate or 8-bromo-cAMP did not show any increased phosphorylation over those of untreated ones, and the phosphopeptide patterns of the immunoprecipitates again were similar to that of CK II phosphorylated protein. These results suggest that HASPP28 is a novel phosphoprotein that can be phosphorylated by several kinases in vitro. In intact cells, CK II seems to be solely responsible for the phosphorylation of HASPP28.

Amino Acid Sequence↗

PubMed1996

Sertoli cell signaling by Desert hedgehog regulates the male germline.

BACKGROUND: In mammals, testis development is initiated in the embryo in response to the expression of the sex determining gene, Sry, in Sertoli cell precursors. Subsequently, Sertoli cells are thought to play a central role in male-specific cell interactions, including those that occur during spermatogenesis. However, the molecular nature of these interactions is poorly understood. Desert hedgehog (Dhh) encodes a signaling molecule expressed in the testis, but not the ovary, and may therefore play a role in the regulation of spermatogenesis. RESULTS: Dhh expression is initiated in Sertoli cell precursors shortly after the activation of Sry and persists in the testis into the adult. Female mice homozygous for a Dhh-null mutation show no obvious phenotype, whereas males are viable but infertile, owing to a complete absence of mature sperm. Examination of the developing testis in different genetic backgrounds suggests that Dhh regulates both early and late stages of spermatogenesis. Patched, a likely target of Hedgehog signaling, also displays male-specific transcription in the gonad. This expression is restricted to a second somatic lineage, the Leydig cells. The expression of Patched is lost in Dhh mutants. CONCLUSIONS: Dhh expression in pre-Sertoli cells is one of the earliest indications of male sexual differentiation. Analysis of a null mutant demonstrates that Dhh signaling plays an essential role in the regulation of mammalian spermatogenesis. Loss of Patched expression in Dhh mutants suggests a conservation in the Hedgehog signaling pathway between flies and mice, and indicates that Leydig cells may be the direct target of Dhh signaling.

Alleles↗

PubMed1996

The T cell receptor gene usage by simian immunodeficiency virus gag-specific cytotoxic T lymphocytes in rhesus monkeys.

MHC class I-restricted CTL play an important role in limiting the spread of HIV-1 in the infected individual. Elucidating the molecular interactions of CTL with the virus is, therefore, of central importance for characterizing the immune control of this infection. In exploring this CTL response, we have defined the TCR usage by SIVmac Gag-specific CTL in rhesus monkeys. Thirty-nine CTL clones were generated from PBL of three SIVmac-infected monkeys expressing the MHC class I Mamu-A*01 gene product, all of which were shown to recognize a single SIVmac Gag peptide in association with Mamu-A*01. Sixty-six percent of CTL clones derived from two monkeys early after infection expressed TCR genes of the V beta 13 family; 70% of these V beta 13+ CTL clones expressed a TCR heterodimer composed of V alpha 1 and V beta 13 gene products. In addition, there appeared to be a selection of a single conserved amino acid and restricted CDR3 lengths in junctional regions of TCR beta-chains expressed by the V beta 13+ CTL clones. These findings indicate significant structural constraints on the CTL-TCR interaction with the AIDS virus. Interestingly, 55% of the CTL clones derived from the third animal at a later time following infection employed genes of the V beta 6 family in their TCR. Despite the preferential use of TCR V family genes by the CTL clones, the SIVmac Gag-specific CTL response was clearly polyclonal; TCR expressed by these CTL clones displayed varied sequences in their CDR3 regions. Other V gene families, including V beta 23, V alpha 8, and V alpha 20, were used in TCR expressed by SIVmac Gag-specific CTL clones. These studies, therefore, indicate that the TCR repertoire of SIVmac Gag-specific CTL that share a peptide and MHC class I recognition specificity can be diverse. Such a broad CTL-TCR repertoire may be advantageous for the host in containing an AIDS virus infection.

Amino Acid Sequence↗

PubMed1996

Major histocompatibility complex class I-dependent cell binding to isolated Ly-49A: evidence for high-avidity interaction.

Ly-49A molecules negatively regulate a subset of mouse natural killer (NK) cells, preventing lysis of H-2Dd-expressing target cells. In the present report, we immunoaffinity-purified Ly-49A from the EL4 lymphoma using the A1 monoclonal antibody (mAb) and examined cell adhesion to immobilized Ly-49A. Adhesion was observed by cells expressing relatively high levels of H-2Dd, but not cells expressing very low or no cell surface Dd, while antibodies specific for Dd or Ly-49A inhibited the cell binding, indicating that Dd and Ly-49A mediate the observed adhesion. The density of immobilized Ly-49A was varied and confirmed by ELISA. Cell binding exhibited a threshold Ly-49A density requirement, and above this threshold, increases in Ly-49A density resulted in substantial increases in cell adhesion to a high maximum cell binding. The density of Ly-49A homodimers required to mediate cell adhesion was found to be quite low: 140-250 molecules/microm2. These results suggest that the avidity of Ly-49A for Dd is relatively high and indicate that small changes in Ly-49A density near the threshold result in large changes in stable Ly-49A receptor engagement. The relatively sharp threshold and marked density dependence presented here for Ly-49A receptor engagement may explain the observation that relatively small differences in Ly-49A expression level on NK cells result in significant differences in functional outcome, i.e. whether a target cell expressing a low level of Dd is spared from lysis or not.

Animals↗

PubMed1996

Factors influencing accuracy of computer-built models: a study based on leucine zipper GCN4 structure.

A three-dimensional model of the leucine zipper GCN4 built from its amino acid sequence had been reported previously by us. When the two alternative x-ray structures of the GCN4 dimer became available, the root mean square (r.m.s.) shifts between our model and the structures were determined as approximately 2.7 A on all atoms. These values are similar to the r.m.s. shift of 2.8 A between the two GCN4 structures in the different crystal forms (C2 and P2(1)2(1)2(1)). CONGEN conformational searches were run to better understand the conditions that may determine the preference of different conformers in different environments and to test the sensitivity of our current modeling techniques. With a judicious choice of CONGEN search parameters, the backbone r.m.s. deviation improved to 0.8 A and 2.5 A on all atoms. The side-chain conformations of Val and Leu at the helical interface were well reproduced (1.2 A r.m.s.), and the large side-chain misplacements occurred with only a small number of charged amino acids and a tyrosine. Inclusion of the crystal environment (C2 symmetry), as a passive background, into the side-chain conformational search further improved the accuracy of the model to an r.m.s. deviation of 2.1 A. Conformational searches carried out in the two different crystal environments and employing the AMBER protein/DNA forcefield, as implemented in CONGEN, gave the r.m.s. values of 2.2 A (for the C2 symmetry) and 2.5 A (for the P2(1)2(1)2(1) symmetry). In the C2 symmetry crystal, as much as 40% of the surface of each dimer was involved in crystal contacts with other dimers, and the charged residues on the surface often interacted with immobilized water molecules. Thus, occasional large r.m.s. deviations between the model and the x-ray side chains were due to specific conditions that did not occur in solution.

Amino Acid Sequence↗

PubMed1996

Enhanced TNF alpha production by monocytic-like cells exposed to dengue virus antigens.

The studies indicating the importance of TNF alpha in dengue virus infection have led us to determine whether monocyte-like cells produce TNF alpha exposure after dengue virus. The supernatant fluids of mosquito cells (AP61) infected with dengue virus (DV) type 1 and DV type 3 were harvested 7 days post-infection and clarified. DV inactivation was performed in the presence of betapropiolactone that preserves antigenicity of viruses. We used the monocytic-like cell line THP-1 that is a model system of TNF alpha production. Polymyxin B (50 micrograms/ml) was added to block untoward effects resulting from possible LPS contamination of media or cultures. THP-1 cells were primed with a phorbol ester (PMA) for 24 h, then they were cultured for 4 and 24 h in the presence of inactivated culture supernatant of dengue infected AP61 cells or control preparations. The concentrations of TNF alpha in the culture supernatants were measured by using an immunoenzymatic assay. PMA-treated THP-1 cells rapidly secreted TNF alpha in response to inactivated culture supernatant of DV-infected cells. We found high levels of TNF alpha with cells exposed to DV1 and DV3 preparations compared with controls (mean values; 465 and 829 vs. 70 pg/ml, respectively, at 24 h post exposure, n = 4). We obtained a substantial inhibition of the enhancing activity of DV1 and DV3 infected supernatants in the presence of dengue hyperimmune mouse ascitic fluids. Our results demonstrate that exposure of monocytes/macrophages to DV particles or virus proteins derived from DV may be responsible for the enhanced production of TNF alpha in DV-infected patients.

Animals↗

PubMed1996

Bioactivation of estrone and its catechol metabolites to quinoid-glutathione conjugates in rat liver microsomes.

Although the carcinogenic effects of estrogens have been mainly attributed to hormonal properties, there is interest in estrogens acting as chemical carcinogens by binding to cellular macromolecules. In the present study, we explored factors which influence the rate of P450-catalyzed formation of the o-quinones (3,5-cyclohexadiene-1,2-diones) from 2-hydroxyestrone (2-OHE) and 4-hydroxyestrone (4-OHE) as well as from estrone in rat liver microsomes. The initially formed o-quinones were trapped as their GSH conjugates which were separated and characterized by HPLC with electrospray-MS detection. Two mono-GSH conjugates were observed from the 2-OHE-o-quinone as well as a conjugate where GSH had added twice to the molecule producing a di-GSH conjugate. 4-OHE-o-quinone gave only one mono-GSH adduct as well as a di-GSH adduct. Both 2-OHE and 4-OHE were excellent substrates for P450, generating o-quinone GSH adducts at 94 and 40 times, respectively, the rate of estrone. 2-OHE but not 4-OHE saturated P450 at unusually low concentrations (0.2 nmol of P450/mL) perhaps due to differences in the stability of the o-quinones formed in the active site of the enzyme. Preliminary data suggest that the o-quinones of both 2-OHE and 4-OHE could isomerize to quinone methides (4-alkyl-2,5-cyclohexadien-1-ones, QMs). The o-quinones of the catechol estrogens were incubated at 37 degrees C (pH 7.4) in the absence of GSH. Aliquots were removed at various times and combined with GSH. From the pseudo-first-order rate of disappearance of the o-quinone GSH adducts, the half-lives of the o-quinones were determined. The o-quinone from 2-OHE has a half-life of 42 +/- 3 s at 37 degrees C (pH 7.4), and the o-quinone from 4-OHE has a half-life of 12.2 +/- 0.4 min under identical conditions. The o-quinones of the AB ring analogs of the catechol estrogens (3,4-dihydroxy-5,6,7,8-tetrahydronaphthalene and 1,2-dihydroxy-5,6,7,8-tetrahydronaphthalene) isomerize to QMs, suggesting that a similar reaction pathway could occur with the o-quinones from catechol estrogens. In support of this, oxidation of 4-OHE and quenching with GSH after 70 min produced 9-dehydro-4-hydroxyestrone (3-hydroxy-1,3,5-(10),9(11)-estratetraen-17-one), a product which could result from either the QM hydrolysis product or the QM--glutathione conjugate, both of which could eliminate to give the conjugated alkene of 4-OHE. The implications of the o-quinone/QM pathway to the in vivo effects of catechol estrogens are not known; however, given the direct link between excessive exposure to endogenous estrogens and the enhanced risk of breast cancer, the potential for formation of additional reactive intermediates needs to be explored.

Animals↗

PubMed1996

p-Quinone methides are the major decomposition products of catechol estrogen o-quinones.

The mechanism of catechol estrogen-induced carcinogenesis could involve alkylation of critical cellular macromolecules by electrophilic quinoids. The o-quinones formed from peroxidase/P450-catalyzed oxidation of catechol estrogens have previously been implicated as the ultimate carcinogens. In the present study, we have shown that additional reactive intermediates can be produced from isomerization of the catechol estrogen o-quinones to highly electrophilic p-quinone methides (QMs). The o-quinones of the catechol estrogens were incubated at 37 degrees C (pH 7.4) in the absence of GSH. Aliquots were removed at various times and combined with GSH. The GSH adducts were isolated and characterized by 1H-NMR, UV, and electrospray mass spectrometry. The o-quinone of 2-hydroxyestrone isomerized to two QMs; a QM stabilized by one alkyl substituent in the B ring, 2-OHE-QM1 (3-hydroxy-1-(10),3(4),5(6)-oestratrien-2,17-dione) and one having two alkyl substituents on the methylene group in the C ring, 2-OHE-QM2 (2-hydroxy-1(2),4(5),9(10)-oestratrien-3,17-dione). Only one QM was observed from the o-quinone of 4-hydroxyestrone, 4-OHE-QM2 (4-hydroxy-1(2),4(5),9(10)- oestratrien-3,17-dione) which is analogous to the C ring analog (2-OHE-QM2) from the o-quinone of 2-hydroxyestrone. The GSH adduct of 4-OHE-QM2 decomposed at pH 7.4 to give 9(11)-dehydro-4-hydroxyestrone as the major product. Finally, the disappearance of the estrogen o-quinone GSH adducts correlated with the formation of the GSH conjugates of the QMs. These data suggest that in cells with low levels of GSH, the formation of these potent electrophiles represents the major reaction pathway for estrogen o-quinones. The implications of the o-quinone/QM pathway for the in vivo effects of catechol estrogens are not known; however, given the direct link between excessive exposure to endogenous estrogens and the enhanced risk of breast cancer, the potential for formation of additional reactive intermediates needs to be explored.

Estrogens, Catechol↗

PubMed1996

Changes in average blood pressure and incidence of high blood pressure 1983-1984 to 1987-1988 in four population cohorts in the People's Republic of China. The PRC-USA Cardiovascular and Cardiopulmonary Epidemiology Research Group.

OBJECTIVE: To assess comparative changes in systolic and diastolic blood pressure and incidence of high blood pressure over 4 years, and factors related to these changes, in northern and southern, urban and rural adults in the People's Republic of China. SETTING: This is a prospective study of populations surveyed by standardized methods in 1983-1984 and 1987-1988 in north China, Beijing area steel mill workers and farmers, and south China, Guangzhou area shipyard workers and farmers. SUBJECTS: The subjects were 8805 men and women aged 35-54 years at baseline (1983-1984), of whom 7338 were non-hypertensive (systolic blood pressure < 140, diastolic blood pressure < 90 mmHg, not being administered antihypertensive drugs). MAIN OUTCOME MEASURES: The main outcome measures were 4-year changes in systolic and diastolic blood pressures and the 4-year incidence of high blood pressure in persons not hypertensive at baseline. RESULTS: At baseline, the average systolic and diastolic blood pressures were higher for Beijing than for Guangzhou cohorts. At resurvey the average systolic blood pressure had increased for seven of eight sex-city-setting cohorts (all but Guangzhou urban men). The Beijing urban cohorts had the greatest increases (men 6.2 mmHg, women 4.9 mmHg, slopes of 1.6 and 1.2 mmHg/year). The incidence of high blood pressure was higher for Beijing than for Guangzhou cohorts in all four comparisons (men and women, urban and rural). Beijing men, urban and rural, had the highest incidence rates (about 21%). In multiple logistic analyses by sex, variables significantly related to 4-year high blood pressure incidence were city, baseline systolic blood pressure and body mass index, change in weight, and, for men, baseline alcohol use and heart rate. CONCLUSION: Modifiable lifestyle traits, previously shown to be related to blood pressure and high blood pressure in cross-sectional studies, also relate to the incidence of hypertension.

Adult↗

PubMed1996

A microassay for determination of the cytopathogenicity of human immunodeficiency virus type-1 isolates.

Correlations between the in vitro biological properties of HIV strains isolated from patients and the prognosis of their disease have been reported. We developed a technique to study the phenotype of HIV strains isolated from patients. We used the P4 cell line, derived from HeLa cells, which has been transfected with receptor CD4 gene. HIV laboratory strain (HIVLAI) and peripheral blood leukocytes (PBLs) from donors infected with HIVLAI induce syncytium in P4 cell cultures in vitro. The presence of reporter gene (LacZ gene) under the control of the HIV-1 long terminal repeat (LTR) in these cells allows colorimetric visualization of syncytia in the cytoplasm using a beta-galactosidase (beta gal) assay in the presence of X-gal. We cocultivated 1 x 10(6) patient PBLs with 2 x 10(6) normal PHA-activated normal PBLs for 4 days in the presence of IL-2 in 24-well plates. Half of the medium was replaced twice a week and PHA-activated normal PBLs were added every 7 days. HIV-1 was isolated from cocultured PBLs of 18 patients with advanced-stage HIV infection as assessed by the production of HIV p24 detected with a commercially available HIV-1 p24 ELISA. Supernatant and 10(5) cells were collected twice a week from cocultured PBLs and were added to P4 cells in 96-well microtiter plates. The cultures were observed every day for 3 days and then the beta gal assay was performed. We did not observe any effect with cells and supernatant from 8 patients, harvested from cultures incubated for as long as 28 days. The phenotype of these isolates was called NC (noncytopathic). In cells from 2 patients, we obtained blue multinucleated giant cells; the phenotype of these strains was called SI (syncytium inducing). In cultures from 8 other patients, we obtained the death of P4 cells without syncytium formation, and the phenotype of these strains was called CI (cell-killing inducing). In every case, the cytopathic effect of HIV-1 isolates could be detected with cocultured PBLs collected as early as day 4 of culture. Cocultured PBLs from 13 healthy controls did not alter the P4 cells. We displayed the replication of CI strains of HIV-1, but not the one of NC strains in P4 cell line. Our micromethod allowed the detection of cytopathic effects of HIV isolates. Further investigations should define the clinical applications of this method.

Coculture Techniques↗