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Biomedical subjects

Z Huang

Publications and source records attributed to Z Huang.

At least 343 records · Page 19Linked to original sources
PubMed1997

[Effect of extremely low frequency (correction of frenquency) magnetic field on brain ischemic reaction in rats].

The effect of extremely low frequency magnetic field (ELMF, 15 Hz, 18 mT) on ischemic brain produced by ligation of general carotid artery in left side was studied in rats. The results showed that the degree of brain blood vessel dilation was higher in magnetic field group than that in control group at the 1st, 3rd and 6th hour after ligation and the extent of damage of neurocyte was apparently lighter in magnetic field group than that in control group at the 3rd and 6th hour after ischemia. It indicates that ELMF stimulation improves the brain blood circulation after brain ischemia and alleviates the brain ischemic reaction.

Animals↗
PubMed1997

[Detection of bcl-2/JH fusion gene in patients with B cell non-Hodgkin's lymphoma by polymerase chain reaction and its clinical implication].

OBJECTIVE: To investigate the frequency and clinical implication of bcl-2/JH gene rearrangement in B cell non-Hodgkin's lymphomas(B-NHLs). METHODS: Major breakpoint region (MBR) and minor cluster region(mcr) of bcl-2 rearrangement were amplified by polymerase chain reaction in fresh tumor tissue, bone marrow and peripheral blood samples from 23 cases of B-NHL. RESULTS: Translocation breakpoint was revealed in 10 fresh tumor tissue (71.4% of follicular NHL, 31.3% of diffuse NHL), 8 bone marrow and 7 peripheral blood specimens. The MBR was involved in most of the cases, while the mcr only in one. In addition, of 18 patients with normal bone marrow morphology, 4 were PCR positive, including 2 in early stage ( I and II). Untreated patients with bcl-2 gene rearrangement obtained lower complete remission rate than those without the rearrangement. CONCLUSION: Detection of bcl-2/JH fusion gene was helpful in diagnosing and staging lymphomas, selecting treatment protocols, and monitoring minimal residual diseases.

Adolescent↗
PubMed1997

[Fluorescence lifetimes of squamous carcinoma, adenocarcinoma and normal human lung tissues in vitro by time-resolved fluorescence].

Using pulsed dye laser 632.8nm, lifetimes of adenocarcinoma, squamous carcinoma and normal human lung tissues in vitro have been measured by time-resolved fluorescence as 5.1, 5.6 and 6.3 ns respectively. Time-resolved fluorescence shows that the decay time of tumor tissues is faster than that of normal tissues. The results may offer new diagnostic method to determine cancer.

Adenocarcinoma↗
PubMed1997

[Simultaneous determination of cobalt and indium by atomic absorption spectrometry].

Present paper describes method which uses solution of simultaneous equations to compensate for spectral "overlap" interference of In 252.137nm with Co 252.136nm. Experimental results show that solution of simultaneous equations is possible method for resolving spectral interference in atomic absorption spectrometry. This method has been applied to determination of Co and In in the samples. Satisfactory results are obtained.

English Abstract↗
PubMed1997

Increases in DNA lesions and the DNA damage indicator Gadd45 following transient cerebral ischemia.

Transient global or focal ischemia leads to the production of several types of lesions in the DNA backbone including alkali-labile sites, and both single-stranded (ss) and double-stranded (ds) breaks. The ds breaks result in high molecular weight fragments of 10-50 kbp that contain both 3'- and 5'-OH end-groups, suggesting that more than one endonuclease is involved. This lesioning of DNA is followed by the appearance of the damage-response indicator Gadd45 in the ischemic hemisphere following middle cerebral artery occlusion. By 6 h, gadd45 mRNA was shown to increase by semi-quantitative reverse transcriptase - polymerase chain reaction. In situ hybridization histochemistry indicated that these increases in gadd45 mRNA occurred in pyramidal neurons located on the edge of the infarcted cortex. Gadd45 immunostaining yielded similar findings with maximal protein staining detected at 18 h after occlusion. In neurons, in the infarct core with frank DNA fragmentation shown by in situ TdT-mediated dUTP-biotin nick end labeling (TUNEL) at 24 h, the Gadd45 immunostaining was not visible. Taken together, these findings suggest that Gadd45 responds to DNA damage following ischemia as part of a repair response mounted by brain cells attempting to survive the insult.

Animals↗
PubMed1997

Complications of laparoscopic cholecystectomy in China: an analysis of 39,238 cases.

OBJECTIVE: To investigate the complications of laparoscopic cholecystectomy in China. METHODS: All Chinese articles about laparoscopic cholecystectomy published between April 1994 and November 1995 were identified through CMCC (Chinese Medical Computerized Contents). From more than 600 titles, 105 articles were screened for analysis. Another 21 articles from the 6th Biliary Surgical Congress and 300 cases from the General Hospital of PLA were added. A total of 39,238 cases of laparoscopic cholecystectomy from 91 hospitals were studied. RESULTS: Severe complications of laparoscopic cholecystectomy were identified in 409 (1.04%) patients, including bile duct injury (in 0.32% of patients), postoperative cystic duct leak (0.11%), postoperative bile leak (0.20%), peritoneal abscess (0.07%), bowel injury (0.06%) and postoperative hemorrhage (0.1%). Fourteen postoperative deaths (0.04%) resulted from operative injury. CONCLUSIONS: The data demonstrate that laparoscopic cholecystectomy is an operation associated with low morbidity and mortality rate, but bile duct injury is still a major problem. Complications of laparoscopic cholecystectomy can be minimized by improving operative procedure.

Bile Ducts↗
PubMed1997

[The development of new-type soft X-ray tube].

This report is based on the technology of image and photo-taking and the creative mecaanism of X-ray. It also analyses the disadvanges of the outanode X-ray tube and the limitations of its clinical practice. Moreover, it clarifies the designing idea and the development result of a new-type soft X-ray tube.

Equipment Design↗
PubMed1997

[An experimental study of bioactive glass ceramics as orbital implants].

One eyeball of experimental rabbits was enucleated in routine procedure, and then implanted the biocative glass ceramic (BGC). No rejection was observed during the postoperation period. After three months of implantation, they were examined with ultrasound, and a venous-flow-like spectra was detected in the ceramic implant. After six months of implantation, the implans were examined histologically; the ingrowth fibrovascular tissue filled the 90% gaps of the implant. The results suggest that the bioactive glass ceramic implants made in China possess acceptable histocompatibility.

Animals↗
PubMed1996

The N-terminal region of the third intracellular loop of the parathyroid hormone (PTH)/PTH-related peptide receptor is critical for coupling to cAMP and inositol phosphate/Ca2+ signal transduction pathways.

Structural determinants within the parathyroid hormone (PTH)/PTH-related peptide (PTHrP) receptor that mediate G-protein activation of adenylate cyclase and phospholipase C are unknown. We investigated the role of the N-terminal region of the third intracellular loop of the opossum PTH/PTHrP receptor in coupling to two signal transduction pathways. We mutated residues in this region by tandem-alanine scanning and expressed these mutant receptors in COS-7 cells and/or Xenopus oocytes. All mutant receptors retained high affinity PTH binding in COS-7 cells, indistinguishable from wild-type receptors. Receptors with tandem-alanine substitutions in two N-terminal segments (377RVL379 and 381TKLR384) demonstrated impaired adenylate cyclase and phospholipase C activation. Receptor mutants with single-alanine substitutions scanning these two segments showed three different signaling defects in COS-7 cells. 1) Two mutant receptors (V378A and L379A) had reduced inositol phosphate (IP), but normal cAMP responses to PTH. 2) Mutant receptor T381A showed reduced cAMP, but wild-type IP responses to PTH. 3) Mutant receptor K382A demonstrated both markedly reduced cAMP and IP production due to PTH. In oocytes, mutants T381A and K382A showed decreased PTH-stimulated cAMP accumulation and intracellular Ca2+ mobilization. Thus, the N-terminal region of the third intracellular loop of this receptor plays a critical role in coupling to both Gs- and Gq-mediated second-messenger generation.

Animals↗
PubMed1996

Genomic organization and DNA sequences of two human phenol sulfotransferase genes (STP1 and STP2) on the short arm of chromosome 16.

A family of human phenol sulfotransferase genes has been suggested by the cloning of numerous cDNA isolates from different tissues. We have previously cloned and sequenced the STM gene encoding the monoamine neurotransmitter-preferring sulfotransferase, M-PST, and a portion of the STP1 gene encoding the phenol-preferring isozyme, P-PST1 (BBRC 205, 1325-1332; Genomics 18, 440-443). Both genes were mapped to a small region on the short arm of chromosome 16 (BBRC 205, 482-489). Here we report on the sequencing and genomic organization of the STP1 and STP2 genes from a single cosmid clone obtained from chromosome 16p12.1-p11.2. STP1 and STP2 are 95.9% identical at the amino acid sequence level, whereas the STM gene is only 92.9% and 90.5% identical to STP1 and STP2, respectively. Alignment of the genomic sequences indicated that all three genes have 7 coding exons and conserved intron-exon boundaries. These results facilitated the assignment of previously published cDNA isolates as "alleles" of the individual STM, STP1, and STP2 loci on 16p, and provide to us a greater understanding of the complexity and roles of the phenol sulfotransferase gene family in the metabolism of endogenous and xenobiotic agents.

Alleles↗
PubMed1996

Large DNA fragment sizing by flow cytometry: application to the characterization of P1 artificial chromosome (PAC) clones.

A flow cytometry-based, ultrasensitive fluorescence detection technique is used to size individual DNA fragments up to 167 kb in length. Application of this technology to the sizing of P1 artificial chromosomes (PACs) in both linear and supercoiled forms is described. It is demonstrated that this method is well suited to characterizing PAC/BAC clones and will be very useful for the analysis of large insert libraries. Fluorescence bursts are recorded as individual, dye stained DNA fragments pass through a low power, focused, continuous laser beam. The magnitudes of the fluorescence bursts are linearly proportional to the lengths of the DNA fragments. The histograms of the burst sizes are generated in <3 min with <1 pg of DNA. Results on linear fragments are consistent with those obtained by pulsed-field gel electrophoresis. In comparison with pulsed-field gel electrophoresis, sizing of large DNA fragments by this approach is more accurate, much faster, requires much less DNA, and is independent of the DNA conformation.

Chromosomes↗
PubMed1996

A simple method for 3'-labeling of RNA.

We describe a simple method for 3'-end labeling RNAs of known sequence. A short DNA template is designed to anneal to the 3'-end of the RNA, with a two nucleotide 5' overhang of 3'-TA-5', 3'-TG-5' or 3'-TC-5'. The Klenow fragment of DNA polymerase I can then cleanly and efficiently extend the 3'-end of the RNA by the incorporation of a single alpha-32P-labeled dATP residue. This method can be used to label one RNA in a mixture of RNAs, or to label 5'-blocked RNAs such as mRNA.

Affinity Labels↗
PubMed1996

Hedgehog, transmitted along retinal axons, triggers neurogenesis in the developing visual centers of the Drosophila brain.

The development of the visual centers of the Drosophila brain is tightly regulated by the ingrowth of retinal axons from the developing eye. In the first optic ganglion, the lamina, arriving retinal axons trigger the precursors of their synaptic partners to complete a final cell division and commence neural differentiation. The secreted product of the hedgehog gene regulates the temporal assembly of photoreceptor precursor cells into ommatidial clusters in the compound eye. Here, we show that Hedgehog is transmitted along the retinal axons to serve as the inductive signal in the brain. Hedgehog acts in the first of two retinal axon-mediated steps in the assembly of lamina synaptic cartridges. These observations provide a novel insight into the molecular interactions that orchestrate the assembly of neural precursor cells into precise synaptic circuits.

Animals↗
PubMed1996

Synthetic peptides derived from the fourth domain of CD4 antagonize off function and inhibit T cell activation.

We have developed synthetic peptide analogs to analyze novel surface structures of the human CD4 protein potentially involved in T cell activation. Linear and cyclic peptides derived from the FG and CC' loops of the membrane proximal fourth domain of CD4 displayed inhibitory activities in a CD4-dependent immunological assay. These results suggest that the fourth domain of CD4 plays an important role in T cell activation. In addition, we report the synthesis of a highly stable CD4 peptide analog cyclized by the formation of an amide bond between amino and carboxyl termini. Serum stability studies showed that this main-chain cyclic CD4 peptide was highly resistant to proteolytic degradation while the linear and disulfide cyclic peptides were much less stable. The strategy of main chain cyclization of CD4 peptides may represent a promising approach to generate proteolytically stable, orally active immunoregulatory agents.

Amino Acid Sequence↗
PubMed1996

Nutrition and subsequent hip fracture risk among a national cohort of white women.

This study investigated three aspects of general nutritional status (dietary intake, biochemical markers, and anthropometric measurements) in relation to subsequent hip fracture risk by using prospective data from the First National Health and Nutrition Examination Survey (NHANES I) epidemiologic follow-up studies. A cohort of 2,513 white women 45 years and over who participated in the NHANES I survey in 1971-1975 were subsequently followed in the three follow-up studies in 1982-1984, 1986, and 1987, respectively. Multiple nutritional variables were measured at baseline, and 130 incident hip fractures were identified by hospital records or by death certificates during the follow-up period. Cox regression analyses showed that baseline dietary energy intake; serum albumin; and weight, body mass index, skinfold, and arm muscle area were significantly and inversely related to subsequent hip fracture risk (relative risks for a 1-standard deviation increment in these variables ranged from 0.68 to 0.83). The authors suggest that poor nutritional status, evident in inadequate dietary intake, reduced serum albumin, and decreased body mass and soft tissues, increases the risk for subsequent hip fracture. The study also showed that age and previous fracture history were significant risk factors; however, self-reported physical activity, parity, and alcohol use were not significantly related to subsequent hip fracture.

Aged↗
PubMed1996

Decreased rat brain cytochrome oxidase activity after prolonged hypoxia.

Three weeks of hypoxic exposure results in a spectrum of systemic physiological and local brain tissue adaptations. Cytochrome oxidase histochemistry was used as an indicator of changes in energy demand in response to hypoxia. We found overall cytochrome oxidase activity decreased in hypoxic adapted rats as compared to normoxic control rats. Some regions, notably layer 3 of the frontal cerebral cortex, layer 4 of the parietal sensory barrel fields, lacunosum moleculare hippocampi, and specific nuclei of the rostral ventral medulla, though exhibiting cytochrome oxidase activity decreases of 16-27%, still retain their relatively higher levels of activity. We conclude that there is a hypometabolic component of the rat brain adaptation to continued hypoxia.

Animals↗