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Biomedical subjects

B Zhou

Publications and source records attributed to B Zhou.

At least 181 records · Page 10Linked to original sources
PubMed1995

[Endoscopic sinus surgery in children].

Thirty-seven cases (67 sides) of chronic sinusitis treated with endoscopic sinus surgery (ESS) at the age of 8 to 17 years were evaluated in the paper. All the patients after ESS were followed up for a period of 2 to 24 months. Twenty-four out of 37 cases were primarily healed, 7 cases had delayed healing and 2 cases still had persistent inflammation during the period of follow-up. Among the 37 cases, 17 recovered completely and 20 recovered incompletely. The necessity, feasibility and indications of ESS in children were discussed.

Adolescent↗
PubMed1995

[Vitrectomy combined with scleral buckling for the treatment of complicated retinal detachment].

PURPOSE: To raise operative successful rate of complicated retinal detachment, we used the methods of vitrectomy combined with scleral buckling for the treatment of complicated retinal detachment. METHODS: The operative methods included: scleral buckling, vitrectomy, membrane peeling, intraocular and extraocular drainage, gas and silicone oil tamponade. RESULT: Being followed up for 1-16 months, 22 eyes got anatomic reattachment in 29 eyes, the operative successful rate was 75.8%; 15 eyes were injected with silicone oil intraocular tamponade, with 12 eyes getting reattachment. The successful rate was 80%. CONCLUSION: Since the vitreous surgery is used, it is possible for the treatment of complicated retinal detachment, the operative successful rate can be raised. The technique of membrane peeling and intraocular tamponade was very important. Silicone oil has been accepted by more and more ophthalologists in the world, which acts as an effective material of intraocular tamponade.

Adolescent↗
PubMed1994

Resolution of proteins on a phenyl-Superose HR5/5 column and its application to examining the conformation homogeneity of refolded recombinant staphylococcal nuclease.

In order to examine the effect of amino acid substitutions on protein retention in hydrophobic interaction chromatography and the resolution of a phenyl-Superose HR5/5 column, two groups of staphylococcal nucleases, named Y113/W140 (wild-type), Y113W/W140 and Y113/W140F, Y113W/W140F, were produced by substituting tryptophan (W) for tyrosine (Y) at residue 113 and phenylalanine (F) for tryptophan (W) at residue 140. For each group, the proteins have the same amino acid at residue 140, but a different amino acid at residue 113. The solvent perturbation of nuclease fluorescence and 1,8-anilinoaphthalene-8-sulfonate binding studies showed that the substitutions do not change the side-chain positions of amino acids at residues 113 and 140. Chromatography of the proteins on the Phenyl-Superose HR5/5 column showed that the proteins with tryptophan at residue 113 have longer retention times than the proteins having tyrosine at residue 113; the proteins with the same amino acid at residue 113 have almost the same retention time regardless of substituting phenylalanine for tryptophan at residue 140. The studies clearly indicate that not all amino acid substitutions have an effect on protein retention; the contribution to retention of a given amino acid substitution depends on its position in a protein. Single amino acid substitutions at the exterior surface of a protein, which change the strength of hydrophobic interaction, can affect the protein retention in hydrophobic interaction chromatography. Staphylococcal nuclease and its mutants with only one amino acid difference on their surfaces can be discriminated by the phenyl-Superose column.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acids↗
PubMed1994

Esophageal balloon cytology and subsequent risk of esophageal and gastric-cardia cancer in a high-risk Chinese population.

Linxian, China has some of the highest rates of esophageal/gastric cardia cancer in the world. In 1983, esophageal balloon cytology screening was performed in 3 communes in northern Linxian. Of the participants, 10,066 with no evidence of cancer were followed prospectively for 7 1/2 years to evaluate the ability of the initial cytologic diagnoses to identify individuals at increased risk for developing cancer of the esophagus or gastric cardia. A total of 747 incident cases of esophageal or cardia cancer and 322 deaths due to these tumors were identified during the follow-up period and used in this analysis. The risks for esophageal or cardia cancer incidence and mortality increased in parallel with the presumed severity of the 1983 Chinese cytologic diagnoses. After adjusting for potential confounding factors, relative risks for esophageal or cardia cancer incidence, by initial cytologic diagnosis, were normal = 1.00 (reference), hyperplasia = 1.25, dysplasia 1 = 2.20, dysplasia 2 = 4.22 and near-cancer = 5.96. Our results suggest that esophageal balloon cytology, as performed and interpreted in Linxian in 1983, successfully identified individuals at increased risk for developing cancer of the esophagus or gastric cardia.

Age Factors↗
PubMed1994

Effect of diallyl trisulfide on the activation of T cell and macrophage-mediated cytotoxicity.

At high concentration (50 micrograms/ml), diallyl trisulfide (DATS) had an inhibitory effect on T cell activation (compared with control group, P < 0.05). But at appropriate concentrations (3.125-12.5 micrograms/ml), DATS augmented the activation of T lymphocytes by Con A (compared with control group, P < 0.01). The augmentation of T cell activation by DATS was related to its inhibitory effect on the production of nitric oxide (NO) by macrophages. In a wide range of concentrations (1-100 micrograms/ml), DATS can inhibit the production of NO by macrophages (P < 0.05, P < 0.01). In addition, DATS can antagonize the inhibition of tumor-derived immunosuppressive factors produced by S180 cells and Ehrlich ascitic cancer cells on the activation of T cells, and reduce the inhibitory rate significantly (P < 0.01). DATS, despite its inhibition of the production of NO by macrophages, can significantly enhance the production of hydrogen peroxide (H2O2) by macrophages. When macrophages were pretreated with DATS for 24 h, the cytotoxicity % of macrophages to three tumor cell lines was significantly higher than that in corresponding control group (P < 0.05, P < 0.01). In the presence of both DATS and LPS, the cytotoxicity of macrophages was further enhanced so that the cytotoxicity % of macrophages to tumor cells was significantly higher than either that in the presence of DATS alone or that in the presence of LPS alone (P < 0.05, P < 0.01). These results indicate that DATS can augment the activation of T cells and enhance the anti-tumor function of macrophage, suggesting that DATS may be potentially useful in tumor therapy.

Allyl Compounds↗
PubMed1994

Double and multiple looped suture tendon repair.

We report our experience of using double or multiple looped sutures for primary tenorrhaphy combined with early active mobilization. In 46 patients involving 51 fingers with flexor tendon lacerations, double threads of the looped nylon suture were placed to repair injured FDP or FDS tendons, or three threads of looped nylon suture were made to repair the FDP tendons. Using White's (1956) criteria, the results were good or excellent in 76.5% of fingers. The double and multiple looped sutures are of sufficient strength to sustain early motion, and cause little disturbance in the circulation. Satisfactory function following primary tendon repair can be expected with these new techniques.

Adolescent↗
PubMed1994

Hormonal control of testicular descent and the cause of cryptorchidism.

This paper briefly reviews the literature on testicular descent and presents new observations from the authors' laboratory which suggest new ways of looking at old problems. There is now good evidence that testicular descent occurs in two morphologically and hormonally distinct phases. Relative 'transabdominal migration' of the testis compared with the ovary occurs at 10-15 weeks of gestation in the human and 'inguinoscrotal' migration occurs at 26-35 weeks of gestation. We have proposed previously that the first phase is controlled by Müllerian inhibiting substance although this remains controversial. The second phase is androgen dependent and is possibly mediated indirectly through the release from the genitofemoral nerve (GFN) of the neuropeptide calcitonin gene-related peptide (CGRP). Recently we have used three different rodent models of undescended testis to determine the involvement of the GNF and/or CGRP. The testicular feminization mouse with complete androgen resistance and the rat exposed prenatally to the antiandrogen flutamide have a deficiency of CGRP in the GFN. In contrast, the mutant trans-scrotal rat which has normal androgen levels has an excess of CGRP in the GFN. All cryptorchidism models, despite their different primary cause, have in common an abnormality of the GNF and/or CGRP which is consistent with the hypothesis that normal testicular descent in the rodent may be mediated by the GFN.

Abdomen↗
PubMed1994

Mechanically induced changes in action potential duration and left ventricular segment length in acute regional ischaemia in the in situ porcine heart.

OBJECTIVE: The electrophysiological events accompanying early ischaemia are important. The aim of this study was to investigate mechano-electric feedback in acute regional myocardial ischaemia in the intact heart in situ by measuring the change in action potential duration in response to increased ventricular loading imposed by transient aortic occlusion. METHODS: 11 landrace pigs were anaesthetised and their hearts exposed. A pneumatically operated blood pressure clamp was placed around the aorta. Monophasic action potentials and an index of segment motion were recorded from the epicardium in and around the ischaemic area produced by a snare placed around a coronary artery. Ventricular and systemic arterial pressures were measured. An initial aortic clamp was performed during which control recordings were taken. The coronary artery was then tied and the aorta clamped for 5-10 s every 5 min for the duration of the 30 min tie. Recordings were taken from the ischaemic area and non-ischaemic areas. RESULTS: Aortic clamp before ischaemia increased intraventricular diastolic and systolic pressure and reduced action potential duration in all the areas studied (p < 0.001). During acute regional myocardial ischaemia aortic clamping resulted in significantly more shortening of the action potential in the ischaemic area after 10 min of ischaemia than in the control area (5 ms v 10 ms, p = 0.008). Over the following 20 min the degree of shortening decreased. The greater shortening at 10 min could not be attributed to changes in the end diastolic segment length or peak ventricular pressure and could thus represent a change in the expression of mechano-electric feedback by ischaemic myocardium rather than a change in loading conditions. CONCLUSIONS: During the first 30 min following a coronary artery occlusion mechano-electric feedback in the ischaemic myocardium varies with time.

Action Potentials↗
PubMed1994

Molecular evolution of the metallothionein gene Mtn in the melanogaster species group: results from Drosophila ananassae.

Three distinctly different alleles of the metallothionein gene Mtn have been identified in natural Drosophila melanogaster populations: Mtn.3, Mtn1, and Dp(Mtn1), where the latter designates a tandem duplication of Mtn1. In Drosophila simulans, only Mtn.3-type alleles have been found. It has been suggested that Mtn.3 is the ancestral allele and demonstrated that a presumed two-step transition from Mtn.3 to Mtn1 to Dp(Mtn1) is accompanied by an approximate 5-fold increase in RNA levels. We analyzed the evolutionary genetics of the Mtn locus of Drosophila ananassae, a distant relative of D. melanogaster and D. simulans within the melanogaster species group. The Mtn gene of D. ananassae is most similar to Mtn.3: (i) it is identical with Mtn.3 at the amino acid level, but differs from Mtn1 in its terminal codon; (ii) its 3' UTR contains a characteristic extra DNA segment of about 50 bp which is present in Mtn.3, but lacking in Mtn1; (iii) duplications of Mtn were not found in a worldwide sample of 110 wild D. ananassae chromosomes. However, the intron of the Mtn gene in D. ananassae is only 69 bp long, whereas the length of the Mtn.3 and Mtn1 introns is 265 bp; and it lacks a polypyrimidine stretch upstream of the 3' splice site in contrast to the much greater pyrimidine-richness found in the Mtn.3 and Mtn1 introns. A short intron (67 bp) was also identified in a D. pseudoobscura Mtn allele, suggesting that the short intron is the ancestral form and that the transition from the short to the long intron occurred within the melanogaster species group.(ABSTRACT TRUNCATED AT 250 WORDS)

Alleles↗
PubMed1994

The relationship of dietary animal protein and electrolytes to blood pressure: a study on three Chinese populations.

The relationship of diet to blood pressure was studied in a total of 705 men and women aged 40-59 from three Chinese population samples having different mean blood pressure and dietary sodium and animal protein intake. Two groups were farmers from Shanxi in northern China, and Guangxi in southern China, and the third were fishermen from Zhejiang, eastern China. Three 24-hour dietary recalls were done for each participant. Serum and overnight urine amino acids were measured in random subsamples. Determination of electrolytes in three 24-hour urine specimens was done in an additional sample of 59 men in each population. Results of multiple or stepwise regression showed: 1) in the pooled group, individual intake of sodium was positively associated with systolic blood pressure; 2) when stratifying by median calcium intake, a positive association of dietary sodium or sodium/potassium was found only in the group with calcium intake lower than the median; 3) daily intake of animal protein, urinary sulphate and certain serum and urine amino acids formed from protein metabolism, were inversely associated with blood pressure.

Adult↗
PubMed1994

[Nasal endoscopic middle meatal antrostomy].

Middle meatal antrostomy under nasal endoscope, a functional procedure which conforms to paranasal sinus physiology, has provided a new approach to reestablishing the ventilation and drainage of nasal cavity and paranasal sinus. A 3-15 month's follow-up of 75 patients with chronic sinusitis and polyps who had undergone endoscopic sinus surgery shows a higher patency rate of 86.7% and a lower closure rate of 13.3%. While for patients who received inferior meatal antrostomy the patency rate was 54.7% and the closure rate 45.3%. There was a significant difference (P < 0.01) between the two groups in patency rate and closure rate respectively. So the antrostomy of middle meatus appears to be better than that of inferior meatus. The clinical significance of middle meatal antrostomy on the basis of anatomy and physiology of paranasal sinus is emphasized in discussion.

Adolescent↗
PubMed1994

[The effects of brain ischemia and electroacupuncture on cortical somatosensory evoked potential in rats].

The dynamic changes of cortical somatosensory evoked potential during occluding bilateral common carotid arteries and electroacupuncturing "Hegu" point were recorded and observed IN 30 wistar rats anesthetized with chloralose and urethane, The main results were as follows: After brain ischemia, P. N. amplitudes of SEP were significantly depressed, and the spike latency of SEP is obviously increased. The decreased amplitude of SEP during brain ischemia could be obviously increased by electroacupuncturing "Hegu" point. It is suggested that SEP may be an indicator to show brain ischemia and acupuncturing "Hegu" point could improve brain ischemia.

Animals↗
PubMed1994

[Multivariate analysis on prognostic factors for acute myocardial infarction during acute period noncondition stepwise logistic model].

The relationship between baseline factors defined at 4.3 +/- 1.8 hr after onset of acute myocardial infarction and 28-day survival in 319 patients admitted into the China Medical University was evaluated. The case fatality rate during acute period was 17.9%. Univariate statistics identified a significant relationship between 5 of these factors and survival. Multivariate noncondition stepwise logistic model analysis identified four factors as being most closely related to survival: (1) heart failure; (2) arrhythmia; (3) age; (4) history of essential hypertension. It is concluded that heart failure during the acute period of acute myocardial infarction is the most important baseline factor for prediction of 28-day survival.

Aged↗
PubMed1994

High-level expression of staphylococcal nuclease A in Escherichia coli.

The staphylococcal nuclease A gene has been successfully cloned and overexpressed in E. coli under the transcriptional control of the bacteriophage lambda PRPL promoters regulated by the temperature sensitive repressors. The SDS-PAGE analysis demonstrates that the nuclease A is produced to the extent of as much as 60% of the total cellular protein. The N-terminal analysis of the nuclease A shows that the amino terminal formyl methionine residue of the enzyme is precisely processed. The recombinant nuclease A with full activity is finally obtained after appropriate solubilization--denaturation and renaturation treatment. The conformational identity of the renatured nuclease A in different conditions is also studied by using hydrophobic interaction chromatography on a phenyl-superose HR5/5 column.

Base Sequence↗
PubMed1994

2',3'-Dideoxycytidine alters calcium buffering in cultured dorsal root ganglion neurons.

Mitochondria play a prominent role in shaping intracellular calcium concentration ([Ca2+]i) transients in dorsal root ganglion neurons. Mitochondrial DNA polymerase is inhibited by antiviral compounds such as 2',3'-dideoxycytidine (ddC). Here, we test the hypothesis that ddC can alter mitochondrially mediated Ca2+ buffering in neurons. Chronic treatment of dorsal root ganglion cultures with ddC (1 microM) lowered mitochondrial DNA levels and decreased the mitochondrially mediated component of depolarization-induced [Ca2+]i transients. The inhibition increased in a time-dependent manner, reaching a maximum at 6 days. ddC did not affect small, action potential-evoked, [Ca2+]i transients that are predominantly buffered by Ca(2+)-ATPases, suggesting that ATP levels were not depleted. The drug did not inhibit whole-cell Ca2+ currents, indicating that the Ca2+ load was not affected. Thus, ddC produces a graded, time-dependent inhibition of mitochondrial function that is reflected, in part, by a decrease in the direct buffering of Ca2+ by mitochondria. This effect may contribute to the peripheral neuropathy that results from ddC treatment. Furthermore, ddC promises to be a useful tool to study the role of mitochondria in [Ca2+]i homeostasis and neurodegenerative processes.

Animals↗