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Biomedical subjects

Z Zeng

Publications and source records attributed to Z Zeng.

At least 109 records · Page 6Linked to original sources
PubMed1997

[Long-term effect of voice rehabilitation in 125 patients following total laryngectomy].

One hundred and twenty-five patients received voice rehabilitation operations following total laryngectomy over the period from August 1977 to December 1994. Among them, 119 were male and 6 were female, the eldest was 70 years old and the youngest 30 years old, and the average age was 55.3 years. Clinical staging was as follows: stage II, 2 cases; stage III, 45 cases; stage IV, 66 cases; and recurrence, 12 cases. The voice rehabilitation operations included pharynx-trachea anastomosis 18 cases and trachea-esophagus fistulization 107 cases. One hundred and fourteen patients were followed-up for 13 months to 18 years. The 3, 5, and 10 year survival rates were 78.2%, 61.4%, and 40.5% respectively. The effective rates of voice rehabilitation according to hearing voice distance were 84.6%, 81.1%, and 67.5% 3 weeks, 1 year, and 5 years respectively after operation. The causes of failure were closure of fistula 15 cases; food aspiration 8 cases and unknown 3 cases. The clinical value, advantages and disadvantages of voice rehabilitation, and the time to evaluate the effect of voice rehabilitation were discussed.

Adult↗
PubMed1996

Molecular cloning and characterization of the human anaphylatoxin C3a receptor.

In a human neutrophil cDNA library, an orphan G-protein-coupled receptor, HNFAG09, with 37% nucleotide identity to the C5a receptor (C5a-R, CD88) was identified. A novel feature of this gene, unlike C5a-R and other G-protein-coupled receptors, is the presence of an extraordinarily large predicted extracellular loop comprised of in excess of 160 amino acid residues between transmembrane domains 4 and 5. Northern blot analysis revealed that expression of mRNA for this receptor in human tissues, while similar, was distinct from C5a-R expression. Although there were differences in expression, transcripts for both receptors were detected in tissues throughout the body and the central nervous system. Mammalian cells stably expressing HNFAG09 specifically bound 125I-C3a and responded to a C3a carboxyl-terminal analogue synthetic peptide and to human C3a but not to rC5a with a robust calcium mobilization response. HNFAG09 encodes the human anaphylatoxin C3a receptor.

Amino Acid Sequence↗
PubMed1996

A mechanism for inducing plant development: the genesis of a specific inhibitor.

Parasitic strategies are widely distributed in the plant kingdom and frequently involve coupling parasite organogenesis with cues from the host. In Striga asiatica, for example, the cues that initiate the development of the host attachment organ, the haustorium, originate in the host and trigger the transition from vegetative to parasitic mode in the root meristem. This system therefore offers a unique opportunity to study the signals and mechanisms that control plant cell morphogenesis. Here we establish that the biological activity of structural analogs of the natural inducer displays a marked dependence on redox potential and suggest the existence of a semiquinone intermediate. Building on chemistry that exploits the energetics of such an intermediate, cyclopropyl-p-benzoquinone (CPBQ) is shown to be a specific inhibitor of haustorial development. These data are consistent with a model where haustorial development is initiated by the completion of a redox circuit.

Journal Article↗
PubMed1996

A cDNA encoding the calcitonin gene-related peptide type 1 receptor.

Calcitonin gene-related peptide (CGRP) is a neuropeptide with diverse biological effects including potent vasodilator activity. We report here the cloning of a complementary DNA (cDNA) encoding a human CGRP1 receptor, which shares significant peptide sequence homology with the human calcitonin receptor, a member of the G-protein-coupled receptor superfamily. Northern blot analysis revealed that the messenger RNA for this receptor is predominantly expressed in the lung and heart. In situ studies showed specific localization of the receptor mRNA to alveolar cells in the lung and to cardiac myocytes in the heart. Stable expression of the cDNA in human embryonic kidney 293 (HEK 293) cells produced specific, high affinity binding sites for CGRP that displayed pharmacological and functional properties very similar to native human CGRP1 receptor. Exposure of these cells to CGRP resulted in a 60-fold increase in cAMP production, which was inhibited in a competitive manner by the CGRP1 receptor antagonist, CGRP-(8-37).

Adrenomedullin↗
PubMed1996

Multiple transcription start sites for the GnRH gene in rhesus and cynomolgus monkeys: a non-human primate model for studying GnRH gene regulation.

In humans, transcription of the gonadotropin-releasing hormone (GnRH) gene can be initiated at two transcription start sites to produce different GnRH mRNAs. The upstream transcription start site is used only in reproductive tissues and tumors. To determine if a similar pattern of GnRH gene expression exists in non-human primates, we cloned GnRH cDNA from rhesus monkey hypothalamic RNA using reverse transcriptase-polymerase chain reaction (RT-PCR) and the 5' flanking region of the monkey GnRH gene by PCR. A 96% similarity between monkey and human GnRH cDNA was found with 94% similarity in the upstream promoter region. An upstream transcriptional start site, was identified in cynomolgus monkey testicular mRNA, 504 base pairs upstream from the hypothalamic site, which was different from that identified in the human GnRH gene. Various cynomolgus monkey reproductive tissues were found to utilize this upstream transcriptional start site. In contrast, no evidence was found for the use of upstream transcriptional start sites in rat testis or placenta, suggesting that the reproductive tissue specificity of the upstream transcription start site may be a primate specific feature.

Amino Acid Sequence↗
PubMed1996

Analysis and Modeling of Time-Dose-Mortality of Melanoplus sanguinipes, Locusta migratoria migratorioides, and Schistocerca gregaria (Orthoptera: Acrididae) from Beauveria, Metarhizium, and Paecilomyces Isolates from Madagascar

A complementary log-log (CLL) model was used to model time-dose-mortality relationships from bioassay tests of 26 fungal isolates mostly from Madagascar, Africa, against three acridid species, all referred to here as "grasshoppers." The fungal pathogens included 15 isolates of Beauveria bassiana, 9 isolates of Metarhizium flavoviridae, and 2 isolates of Paecilomyces spp. Grasshopper species tested included Melanoplus sanguinipes, Locusta migratoria migratorioides, and Schistocerca gregaria. The scaled deviance, mean deviance, Pearson X2 statistic, Hosmer-Lemeshow (H-L) C statistic, and three-dimensional time-dose-mortality graphs were used to assess extra-binomial variation, data points that were potential outliers, conformance of the scaled deviance statistic and Pearson's X2 statistic to a chi2 distribution, and the fit of the CLL model. The H-L C statistic also was found to be useful in showing the goodness of fit of the CLL model for the fungal isolates prior to modeling the extra-binomial variation. After the extra-binomial variation was modeled using Williams' method, the slope from maximum likelihood estimation, modified log(LD50) estimates (which were corrected for background mortality using the CLL model), a dynamic ranking of the log(LD50) values over time, and a three-dimensional plot of time, dose, and mortality of the three grasshopper species were used to evaluate the effectiveness of the fungal isolates. In general, the CLL model provided a rather poor fit of the fungal isolates which had a large number of replicate trials in the bioassay tests (i.e., a large sample size) due to extra-binomial variation. The CLL model provided an excellent fit of the time-dose-mortality relationships of such isolates after the extra-binomial variation was modeled and included in the CLL model. Metarhizium isolates MFV and SP5 were found to be the most virulent isolates tested against M. sanguinipes, followed by Metarhizium isolates: SP8, SP7, SP9, SP6, and SP1, and Beauveria isolate S33B. Metarhizium isolates SP3, SP5, SP6, and SP9, and Beauveria isolates SP11, SP12, SP13, and SP16 showed higher levels of virulence against L. migratoria migratorioides over more of the time periods tested than the other pathogen isolates examined. Metarhizium isolates SP9 and SP5 were the most effective isolates tested against S. gregaria. In general, the Metarhizium isolates were more virulent against the grasshoppers than the Beauveria isolates, which were more virulent than the Paecilomyces isolates. The CLL model was found to be very useful in describing grasshopper mortality as a function of time and dose. This approach combined with model and fungal isolate assessment statistics will be helpful for determining which pathogen isolates have the greatest potential for controlling grasshoppers and other pests in the future.

Journal Article↗
PubMed1996

Fate of 4"-epiacetylamino-4"-deoxyavermectin B1 in rats.

Distribution, excretion, and metabolism of 4"-epiacetylamino-4"-deoxyavermectin B1 (AAB1), a new avermectin, were determined in Sprague-Dawley VAF rats. The rats were dosed orally for 7 consecutive days at approximately 6 mg/kg body weight with [5-3H]AAB1 as a 1.2 mg/ml aqueous suspension containing 0.5% methyl cellulose. Rats were killed at approximately 7 hours and 1, 2, and 5 days after the last dose. The major route of excretion of drug residues was via feces, with less than 1% of the dose found in urine. The radioactive residue levels in tissues and blood followed the order GI > liver approximately equal to fat approximately equal to kidney > muscle > plasma approximately equal to red blood cells and were comparable in male and female rats. HPLC-radiochromatographic profiles revealed that 4"-epiamino-4"-deoxyavermectin B1a was the major metabolite in all tissue samples and plasma samples, and was usually the major residue at later time points. The results indicate that N-deacetylation of AAB1 was the primary route of metabolism in rats. A distinct feature of the metabolism was a sex difference in the extent of metabolism. When metabolite profiles of male and female rats killed at the same time were compared, less parent drug and more of the N-deacetylated metabolite were found in the female rats, indicating that the drug was metabolized more extensively in female rats than in male rats. The sex difference in the extent of metabolism was also demonstrated in vitro.

Animals↗
PubMed1996

[Secretion of endothelin-1 by cultured human normal adrenal cells].

Endothelin (ET) is a vasoactive peptide produced by some other types of cells in addition to endothelial cells. The authors investigated into the possibility of ET-1 secretion by cultured human normal adrenal cells. Human normal adrenal cells were prepared by 2% collagenase digestion for 1.5 hours and cultured in DMEM supplemented with 10% FCS. Angiotensin I (10(-9)-10(-7) mol/L) was added to the experimental groups on the 7-9th days of cultivation. Mediums were collected after 24 hours and the levels of aldosterone, cortisol and ET-1 in the mediums were measured by RIA. Other than aldosterone and cortisol, ET-1 was detected in the cultured mediums of human normal adrenal cells. And the secretion of ET-1 was stimulated by angiotesin I. Therefore, it is proposed that ET-1 may play a role by autocrine or paracrine in the human normal adrenal gland.

Adrenal Glands↗
PubMed1996

[Effect of tetramethyl pyrazine on coronary vasoconstriction induced by endothelin-1 in dogs].

The purpose of this study was to determine the antagonistic effect of tetramethyl pyrazine (TMP), a sort of chinese herbal medicine, on coronary vasoconstriction induced by endothelin-1 (ET-1) in closed chest dogs. ET-1 at doses of 50, 75 and 100 pmol was selectively administered into left main coronary artery and coronary angiogram was performed in 1, 3 and 10 minutes after intracoronary administration of ET-1. After a 60 minute interval ET-1 administration and coronary angiogram were repeated in two groups in group A with 5 dogs intravenous infusion of saline solution was administered while in group B with 4 dogs TMP was infused at a dose of 80 mg/kg. Blood pressure of intra-femoral artery, heart rate and ECG were monitored during the experiment. The study demonstrated that coronary vessel diameter significantly decreased by 17% (P < 0.02) in group A and 20% (P < 0.02) in group B, associated with ischemia in ECG (4/5 in group A and 3/4 in group B) after intracoronary administration of ET-1. Endothelin-1 induced coronary vasoconstriction and ischemic changes in ECG were significantly inhibited by intravenous TMP. The coronary diameter increased by 20% (P < 0.03) after administration of TMP, comparing with the control group. Heart rate had an increased response to TMP. In conclusion this study demonstrated that intracoronary administration of ET-1 caused significant myocardial ischemia through coronary vasoconstriction, which was inhibited by TMP. TMP significantly dilated coronary artery.

Animals↗
PubMed1996

Changes of plasma endothelin concentrations before and after percutaneous balloon mitral valvuloplasty in patients with mitral stenosis.

Plasma concentrations of endothelin in blood from the femoral vein and the antecubital vein were measured in 35 patients with mitral stenosis and heart failure before and after percutaneous balloon mitral valvuloplasty (PBMV). The basal plasma concentrations of endothelin in blood from the antecubital vein in the patients were significantly higher than those in 32 control subjects (15.40 +/- 3.32 vs. 9.59 +/- 2.66 pg/ml, P < 0.001). Plasma endothelin concentrations in patients in New York Heart Association functional classes II and III were significantly higher than those in control subjects, respectively. The concentrations of endothelin in patients with atrial fibrillation were also significantly higher than those in patients with normal sinus rhythm. Ten to fifteen minutes after PBMV, plasma endothelin concentrations in blood from the femoral vein significantly decreased from 16.14 +/- 3.34 to 13.74 +/- 3.78 pg/ml (P < 0.01). Seventy-two hours after the procedure, the concentrations of endothelin in blood from the antecubital vein had fallen to 12.31 +/- 2.55 pg/ml (P < 0.001 vs. before PBMV and control subjects). Plasma endothelin concentrations still tended to be higher in patients with atrial fibrillation than those in normal sinus rhythm, but the difference did not reach statistical significance. There were weak but significantly correlations of plasma endothelin concentrations with the mean left atrial pressure (r = 0.424, P < 0.001), mean right atrial pressure (r = 0.323, P < 0.01), mean transmitral pressure gradient (r = 0.397, P < 0.001), heart rate (r = 0.350, P < 0.005) and mitral valve area (r = -0.454, P < 0.001) in the patients before and after PBMV.

Adolescent↗
PubMed1996

[A simplified method for detection of genomic subtyps of HBV S-gene].

When the 513 bp amplified fragments of HBV S-gene, known subtypes, were digested with Msp I and BamH I, the following phenomena appeared: adr subtypic 513 bp was fragmentized to 320 bp and 193 bp by Msp I; ayw subtype was digested and fragmentized to 295 bp and 218 bp by BamH I; ayw could also be fragmentized to become 326 bp and 187 bp digested by Msp I. Howerev, adw subtype was not digested by Msp I and BamH I nor adr by BamH I. The experimental patterns in agarose gel electrophoresis were tallied with the expected patterns. Each HBV subtypes gave unique size of digestive fragments which was easy to observe and distinguish on agarose gel. This study provided a new classification scheme for HBV-DNA and could be used for epidemiological investigation of HBV infection.

DNA, Viral↗
PubMed1996

[Acupuncture and cortical evoked potentials].

Research works for the effects of acupuncture on cortical evoked potentials were reviewed since 1970 in this article. As a result of the acupuncture anesthesia being applied widely in clinical operation, most of the studies were focused on the evoked potential of somatosensory cortex for elucidating the principle of the analgesic effect of acupuncture, while less observations were reported on the aspects of auditory and visual cortex. The amplitude of the evoked potential was often used as an index in assessing the excitability of the cerebral cortex in the studies of the effect of acupuncture in the past. An increase in the amplitude of evoked potential means an excitory process of the cortex and a decrease means depression. Based on their work, the authors consider that whether the change in the amplitude of cortical evoked potential could be served as an optional index in reflecting the excitability of the cortex is still a problem in neurophysiology remained for further investigation.

Acupuncture Therapy↗
PubMed1996

Crystal structure determination of an acidic neurotoxin (BmK M8) from scorpion Buthus martensii Karsch at 0.25 nm resolution.

The crystal structure of an acidic neurotoxin, BmK M8, from Chinese scorpion Buthus martensii Karsch was determined at 0.25 nm resolution. The X-ray diffraction data of BmK M8 crystals at 0.25 nm resolution were collected on a Siemens area detector. Using molecular replacement method with a basic scorpion toxin AaH II in a search model, the cross-rotation function, PC-refinement and translation function were calculated by X-PLOR program package. The correct orientation and position of BmK M8 molecule in crystal were determined in a resolution range of 1.5-0.35 nm. The crystallographic refinement was further performed by stereo-chemical restrict least-square technique, followed by simulated annealing, slow-cooling protocols. The final crystallographic R-factor at 0.8-0.25 nm is 0.171. The standard deviations of bond length and bond angle from ideality are 0.0017 nm and 2.24 degrees, respectively. The final model of BmK M8 structure is composed of a dense core of secondary structure elements by a stretch of alpha-helix with two and a half turns (residues 19-28) and a three-stranded antiparallel beta-sheet (residues 2-4, 32-37, 45-51). In addition, three loops protruded from the structural core. The general folding properties of BmK M8 molecule were described; a common structure motif which may appear in all scorpion neurotoxins was identified. The conserved aromatic residues and charged residues were found to be distributed on two roughly opposite surfaces of the molecule. The relationship between these two faces and receptor-binding sites are also discussed.

Animals↗
PubMed1996

[Immunohistochemical study of endothelin-1 in adrenal tumors].

10 cases of aldosteronoma, 10 cases of pheochromocytoma and 10 cases of adrenocortical adenoma and hyperplasia were studied by using immunohistochemical staining for ET-1. All of the tumors were stained positivily for ET-1, ranging from weak diffuse (+) staining to moderate staining (++). In aldosteronomas ET-1 receptro may be down-regulated and ET-1 may play a paracrine role in regulating catecholamine in pheochromocytoma.

Adolescent↗
PubMed1996

[Effects of L-arginine on acute hypoxic pulmonary hypertension and production of endothelin-1 in vivo and in cultured endothelial cells].

This study is aimed to investigate the effects of L-arginine, a precursor of the formation of nitric oxide, on acute hypoxic pulmonary hypertension in vivo and on production of endothelin-1 both in vivo and in cultured endothelial cells. In mechanically ventilated anesthetized dogs (n = 7), L-arginine (0.5 g/kg) reduced the mean pulmonary arterial pressure and femoral arterial pressure during hypoxic ventilation and its action lasted for about 30 minutes. Meanwhile, plasma endothelin-1 in the pulmonary and femoral artery had no remarkable change. In cultured endothelial cells from umbilical veins, different concentrations of L-arginine had no influence on endothelin-1 level of culture medium in 4 or 24 hours after the addition of L-arginine. These results indicate that L arginine can decrease the pulmonary arterial pressure during acute hypoxia, which may be associated with the increase of nitric oxide production.

Animals↗
PubMed1996

[A morphometric study on hippocampus of epileptic rats induced by coriaria lactone].

This experiment was carried out with these rats were injected with 3.8 microliters (19 micrograms) convulsive dosage of coriaria lactone (CL) in the left cerebral motor cortex of the forelimb to induce acute focal epilepsy, while the other 5 rats as controls (no seizure) received normal saline solution of the same volume and at the same location. The brains were taken after seizuring for 60 min. The volume (water displacement method) and weight of the brain were measured. The brain was cut coronally and the structures of hippocampus were compared morphologically with those of the pair-matched control. The area of hippocampal formation was measured with paraffin section by test grid under 40x. The mean size (Feret's diameter) of pyramidal neurons in CA1 region was measured with semithin section by ocular micrometer under 1000x. The areal fraction of several organelles of the CA1 pyramidal cells was measured with EM negative film by magnifier. Under conditions of the consistent reference space, especially the size of CA1 pyramidal cells, the areal fraction of rough endoplasmic reticulum, lysosome and mitochondria increased significantly (P < 0.05) in epileptic rats. It indicated that their volume increased. The results show that certain ultrastructural changes have taken place after seizuring for 60 min.

Animals↗