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Biomedical subjects

W Zhou

Publications and source records attributed to W Zhou.

At least 343 records · Page 19Linked to original sources
PubMed1995

Protective effects of nifedipine and allopurinol on high energy shock wave induced acute changes of renal function.

In a prospective randomized study, the effects of a calcium antagonist (nifedipine) and a xanthine oxidase inhibitor (allopurinal) on high energy shock wave induced impairment of renal function were examined. A total of 40 patients with renal pelvis or caliceal stones undergoing anesthesia-free extracorporeal shock wave lithotripsy (ESWL) without auxiliary measures was randomly assigned to 4 groups. Group 1 received no medication and the others received nifedipine (group 2), allopurinol (group 3) or nifedipine plus allopurinol (group 4), respectively. Nifedipine (20 mg. each) or allopurinol (0.2 gm. each) was given orally 3 times a day for a total of 4 days beginning the night before ESWL. To assess renal function the urinary excretions of beta 2-microglobulin, albumin and Tamm-Horsfall protein were determined by radioimmunoassay. After ESWL there was a significant increase in urinary beta 2-microglobulin and albumin (p < 0.001), and the urinary Tamm-Horsfall protein decreased significantly (p < 0.01) compared with before ESWL in group 1. In groups 2 and 4, however, all of the parameters after ESWL were not significantly different compared with the values before ESWL. Although the levels of urinary beta 2-microglobulin and albumin after ESWL were significantly higher (p < 0.05) than the pre-ESWL levels in group 3, the changes in urinary albumin and Tamm-Horsfall protein were milder in group 3 than in group 1. In addition, the urinary albumin level in group 2 and the urinary beta 2-microglobulin or albumin level in group 4 were less significantly different (p < 0.05) than the levels in group 1. All parameters before ESWL were not significantly different among the groups. Our results indicated that nifedipine and/or allopurinol exhibits a protective effect on high energy shock wave induced renal damage.

Adolescent↗
PubMed1995

[Analysis of HLA-DRB1 alleles in patients with IDDM].

HLA-DR association with IDDM in local population in Beijing was studied by PCR/SSP typing. The frequency of HLA-DR9 was significantly higher in diabetic patients (30.3% [45/148] vs 17.92% [38/212], chi 2 = 6.97, P < 8.3 x 10(-3)). DR3 was higher in diabetic patients in this study (7.0% [10/148] vs 2.36% [5/212], chi 2 = 3.19, P > 0.05) and DR2 was lower in patients with IDDM (7.4% [11/148] vs 19.8% [42/212], chi 2 = 9.67, P < 1.9 x 10(-3)). These results suggest that DR9 and DR3 both were positively associated with IDDM, but DR2 was negatively associated with IDDM.

Adolescent↗
PubMed1995

[Hoffa disease: diagnosis and arthroscopic treatment].

The diagnosis of Hoffa disease (syndrome of impigement of the infrapatellar fat pad) was established in 20 patients with anterior knee pain by clinical physical examination, magnetic resonance imaging and arthroscopic findings. Arthroscopic partial or total resections of the infrapatellar fat pad were performed after arthroscopic examination. According to the Larson's rating score for knee function, 18 cases had a satisfactory result at an average follow-up of 36 months. The results of follow-up also suggested there was no significant difference between the partial and total resections of the fat pad.

Adipose Tissue↗
PubMed1995

[Arthroscopic evaluation and treatment of the disorder resulted from open meniscectomy of the knee].

Between 1989 and 1994, twenty four cases of knee disorders caused by open meniscectomy had undergone the second operation by arthroscopic procedures. The results of retrospective study indicated that main reasons of early disorders following meniscectomy were locking of remanent posterior horn, tears of remanent meniscus and injuries of fat pad and the cause of late disorders were single compartment osteoarthritis and genu varum/valgum caused by meniscectomy. In early cases, the arthroscopic reshape or removal of meniscal remanents and partial resection of fat pads could get satisfactory results. In late cases of osteoarthritis with genu varum/valgum, arthroscopic debridement, high osteotomy of tibia or knee replacement should be carried out as means of treatment.

Adult↗
PubMed1995

Effect of phorbol ester on cAMP-dependent protein kinase activity in cardiomyocytes.

Cardiomyocytes isolated from neonatal rats were treated with phorbol-12-myristate-13-acetate (PMA) ranging from 10(-11) to 10(-7) mol/L for 20 min, causing cytosol protein kinase A (PKA) activity to decrease while particulate PKA activity increase in a concentration-dependent manner. The change of PKA activity induced by PMA was abolished completely by pretreatment of polymyxin B or depletion of protein kinase C (PKC). Type II PKA activity in particulate fraction was enhanced remarkably, while that of type I PKA was not altered when the cells were treated with 100 nmol/L PMA. The results suggested that subcellular distribution and activity of PKA in cardiomyocytes may be regulated by PKC.

Animals↗
PubMed1995

Experimental studies of the effect of Forskolin on the lowering of intraocular pressure.

PURPOSE: To determine the effect of domestic Forskolin on lowering of intraocular pressure (IOP) in rabbits. METHODS: Measure the normal IOP and ocular hypertension by water load in rabbits using Perkins tonometer. Measure the adenylate cyclase (AC) activity by Ho & Sutherland's method. RESULTS: The results show that Forskolin significantly lowered the normal IOP of rabbits and blocked the ocular hypertension induced by water load in rabbits (P < 0.01). The maximum decrease value of 2%, 1% and 0.5% of the Forskolin was 0.59, 0.36 and 0.19 kPa (1kPa = 7.5 mmHg), which showed the noticeable dose-effect relationship. Topical ocular application of Forskolin lowered IOP in half an hour, reached to a peak in 2-3 hours and remained significantly for 10 hours. The pupillary diameter did not change when IOP was reduced. The Forskolin had potent stimulative properties to AC. The greater the ability of the Forskolin to stimulate AC, the stronger the effect of IOP lowering. CONCLUSIONS: The Forskolin had the effect on lowering the IOP of rabbits. The mechanism of IOP reduction by Forskolin is related to its AC activation.

Adenylyl Cyclases↗
PubMed1995

[Prognosis of hypopharyngeal and esophageal cancers treated with different surgical procedures].

Thirty-nine cases of hypopharyngeal and 21 cases of cervical esophageal carcinomas were resected and different organs and tissues were used for reconstruction. Among them, the stomach was used as substitute for the esophagus in 33 cases the colon in 20, the myocutaneous flap in 4 and the gastric tube in 3. Three-year and 5-year survival rates were 61.2% and 37.9% respectively. Of the post-operative deaths within 5 years, 40.5% was due to local recurrence and 35.1% due to metastasis to cervical lymphnode. In patients who had negative lymphnode findings before operation, positive results were obtained in 42.1% of the cervical lymphnodes and in 27.2% of the tracheoesophageal groove and superior mediastinal lymphnodes resected. Reoperation was performed in 5 cases with local recurrence and 8 cases with cervical lymphnode metastasis and the resectabilities were 40.1% and 37.9% respectively. The authors consider that among these operative procedures, the colonic interposition with pharyngocolonic anastomosis had the following advantages: (1) excellent physiological function; (2) higher successful rate; (3) lower local recurrence incidence; and (4) good living quality.

Adult↗
PubMed1995

[A study on method of measurement and analysis of anterior chamber configuration by computerized image processing].

A new computerized method of measurement and analysis of the anterior chamber configuration in the human eye is described. The image or photograph of the anterior chamber taken with a slitlamp microscope is inputted into a computer with digitized camera or digitizer. After cornea, iris and lens surfaces are digitized, methematical corrections are made for the distortion from the slitlamp microscope and the refractive effect of cornea and aqueous humor to convert an optic distorted image into a true image. From the corrected image of anterior chamber, the data and parameter of anterior chamber configuration are measured and calculated. The reproducibility and accuracy of the method were 1.78% approximately 4.66% and 0.05 mm respectively and found to be adequate for clinical study of human eye under physiologic or disease state.

Anterior Chamber↗
PubMed1995

[The study of correlation between hemorrheology and fluorescein angiography in open-angle glaucoma].

PURPOSE: To observe the correlation between hemorrheology and arm-retinal filling time of fluorescein angiogaphy in patients with primary open-angle glaucoma. METHODS: The whole blood apparent viscosity in high (125 S-1), moderate (23 S-1) and low (1.2435 S-1) shear rates, plasma viscosity and hematocrit were measured in 50 cases (50 eyes) with primary open-angle glaucoma whose intraocular pressures were controlled. They also underwent fluorescein angiography. The duration from arm to retina arteria filling was named arm-retinal arteria filling time. RESULTS: There were positive correlation between the whole blood apparent viscosity in high and moderate shear rates, hematocrit and arm-retinal arteria filling time (P < 0.05-0.005). The higher blood viscosity, the longer arm-retinal arteria filling time. CONCLUSION: The blood viscosity in patients with primary open-angle glaucoma can affect the arm-retinal arteria filling time of fluorescein angiography. So, the increasing blood viscosity in patients with primary open-angle glaucoma can reduce the blood supply to the optic disc.

Adolescent↗
PubMed1995

[Evaluation of accuracy of measuring intraocular pressure by handheld non-contact applanation tonometer].

PURPOSE: To evaluate the accuracy of measuring intraocular pressure by handheld non-contact applanation tonometer. METHOD: 58 patients' (113 eyes) intraocular pressure were measured by Keeler, non-contact tonometer and R 900 Goldmann applanation tonometer and the results of measurement of intraocular pressure by the two kinds of tonometers were compared. RESULT: The mean intraocular pressure measured by non-contact is 16.31 +/- 5.59 mmHg and 17.49 +/- 6.13 mmHg (1 mmHg = 0.1333 kPa) by Goldmann applanation tonometer, respectively. There was no statistical significance to be found (P > 0.05) between the two methods. By linear correlation and regression analysis, a positive correlation was found between the two methods (r = 0.8942, b = 0.8154). CONCLUSION: The handheld non-contact tonometer has the same accuracy and reliability of measurement of intraocular pressure comparing with Goldmann applanation tonometer, and it can be used in glaucoma clinic and screening.

Evaluation Studies as Topic↗
PubMed1994

The tsA58 simian virus 40 large tumor antigen disrupts megakaryocyte differentiation in transgenic mice.

Thrombocytopenia is a condition of multiple etiologies affecting the megakaryocyte lineage. To perturb this lineage in transgenic mice, the tsA58 mutation of the simian virus 40 large tumor antigen was targeted to megakaryocytes using the platelet factor 4 promoter. Ten of 17 transgenic lines generated exhibited low platelet levels, each line displaying a distinct, heritable level of thrombocytopenia. Within a line, the degree of the platelet reduction correlated directly with transgene zygosity. The platelet level could be further reduced by the inactivation of one copy of the endogenous retinoblastoma gene. Western blot analysis detected large tumor antigen protein in the most severely affected lines; less affected lines were below the level of detection. Platelets and megakaryocytes from thrombocytopenic mice exhibited morphological abnormalities. Mice with either normal or reduced platelet levels developed megakaryocytic malignancies with a mean age of onset of about 8 months. There was no correlation between severity of thrombocytopenia and onset of malignancy. These mice provide a defined genetic model for thrombocytopenia, and for megakaryocytic neoplasia, and implicate the retinoblastoma protein in the process of megakaryocyte differentiation.

Animals↗
PubMed1994

Transcription bypass or blockage at single-strand breaks on the DNA template strand: effect of different 3' and 5' flanking groups on the T7 RNA polymerase elongation complex.

We have studied the effects of single-strand breaks present on the template strand during T7 RNA polymerase transcription elongation. A synthetic DNA template with a T7 promoter was designed to contain a one-nucleotide gap at a defined location on the template strand. This gap, surprisingly, was efficiently bypassed by T7 RNA polymerase during transcription elongation, and the full-length transcript (FLT37) generated from the bypass event was shortened by one nucleotide compared to the full-length transcript (FLT38) generated from an intact, unbroken template strand. FLT37 did not contain any nucleotide insertions opposite to the gap, so that the RNA sequence downstream from the gap, although accurately transcribed, contained a single base deletion compared to FLT38. This, to our knowledge, is the first demonstration that the continuity of the DNA template strand is not a necessary requirement for DNA-dependent RNA polymerase transcription elongation. DNA templates with different 3' and 5' termini at the single-strand break site were also investigated in this study. One of these templates, 1/3P-4P, which contained 3'- and 5'-phosphoryl termini at the break site, efficiently blocked T7 RNA polymerase. A single phosphoryl group present on either the 3' or the 5' terminus of the break site did not efficiently block RNA polymerase progression, suggesting that the blockage observed with template 1/3P-4P is due to the repulsion between the two phosphoryl termini in the vicinity of the polymerase active site.

Base Sequence↗
PubMed1994

Amino-terminal basic residues of Src mediate membrane binding through electrostatic interaction with acidic phospholipids.

Membrane targeting of pp60src (Src) is mediated by its myristoylated amino terminus. We demonstrate that, in addition to myristate, six basic residues in the amino terminus are essential for high-affinity binding to the lipid bilayer via electrostatic interaction with acidic phospholipids. Specifically, c-Src was shown to bind 2500-fold more strongly to vesicles composed of the physiological ratio of 2:1 phosphatidylcholine (PC)/phosphatidylserine (PS) than to neutral PC bilayer vesicles. The apparent Kd for binding of c-Src to the PC/PS bilayer was 6 x 10(-7) M. This interaction is sufficiently strong to account for c-Src membrane targeting. Mutants of c-Src in which the amino-terminal basic residues were replaced by neutral asparagine residues exhibited binding isotherms approaching that of wild-type binding to neutral bilayers (apparent Kd of 2 x 10(-3) M). The transforming v-Src and activated c-Src (Y527F) proteins also bound more strongly to PC/PS bilayers (apparent Kd of approximately 1 x 10(-5) M) than to neutral PC bilayers. In vivo experiments with Src mutants confirmed the role of positive charge in mediating membrane binding and cellular transformation.

3T3 Cells↗
PubMed1994

Glutamate 301 of the mouse gonadotropin-releasing hormone receptor confers specificity for arginine 8 of mammalian gonadotropin-releasing hormone.

The Arg residue at position 8 of mammalian GnRH is necessary for high affinity binding to mammalian GnRH receptors. This requirement has been postulated to derive from an electrostatic interaction of Arg8 with a negatively charged receptor residue. In order to identify such a residue, 8 conserved acidic residues of the mouse GnRH receptor were mutated to isosteric Asn or Gln. Mutant receptors were tested for decreased preference for Arg8-containing ligands by ligand binding and inositol phosphate production. One of the mutants, in which the Glu301 residue was mutated to Gln, exhibited a 56-fold decrease in apparent affinity for mammalian GnRH. The mutant receptor also exhibited decreased affinity for [Lys8]GnRH, but its affinity for [Gln8]GnRH was unchanged compared with the wild type receptor. The apparent affinity of the mutant receptor for the acidic analogue, [Glu8]GnRH, was increased more than 10-fold. The mutant receptor did not, therefore, distinguish mammalian GnRH from analogues with amino acid substitutions at position 8 as effectively as the wild type receptor. This loss of discrimination was specific for the residue at position 8, because the mutant receptor did distinguish mammalian GnRH from analogues with favorable substitutions at positions 5, 6, and 7. These findings show that Glu301 of the GnRH receptor plays a role in receptor recognition of Arg8 in the ligand and are consistent with an electrostatic interaction between these 2 residues.

Amino Acid Sequence↗
PubMed1994

A mechanism for phorbol ester-mediated regulation of the PAF receptor in human neutrophils.

Phorbol esters induce rapid downregulation of PAF receptors on human neutrophils. The molecular mechanism responsible for this observation has not been elucidated. In the present study, treatment of neutrophils with PMA (10(-7) M) for 10 min caused a complete loss of PAF receptors from the cell surface as determined by specific radioligand binding. This loss of PAF receptors was associated with an inhibition of a PAF-induced increase in [Ca2+]i. Evidence presented in this study suggests that the rapid loss of PAF binding sites from the neutrophil surface is due to PMA-induced PAF receptor internalization and/or redistribution of cellular PAF receptors. This contention is based upon: (i) disruption of PMA-treated neutrophils exposed latent PAF binding sites, while PAF receptors downregulated following A23187 treatment failed to recover upon cell disruption; (ii) PMA-induced PAF receptor downregulation was not observed in cell homogenate preparations, suggesting that cellular integrity which facilitates receptor internalization or redistribution was required; (iii) cytochalasin B, an agent capable of disrupting microfilaments, attenuated PMA-induced PAF receptor downregulation. This phenomenon was reproduced in human mononuclear cells. Thus, the cellular basis for PMA-induced PAF receptor loss from human neutrophils and mononuclear leukocytes likely involves internalization or cellular redistribution of the PAF receptor.

Calcimycin↗