Biomedical subjects

T Zhang

Publications and source records attributed to T Zhang.

At least 415 records · Page 23Linked to original sources

PubMed1991

[Duodenal ulcer disease: Helicobacter pylori and hyperchlorhydria].

Basal and pentagastrin-stimulated gastric acid secretion and basal serum gastrin level were investigated in 55 active duodenal ulcer patients with antral colonization with Helicobacter pylori (HP) and 17 patients without. Our study shows that basal (BAO) and pentagastrin-stimulated gastric acid secretion (MAO and PAO) were significantly higher in HP positive than in HP negative patients with duodenal ulcer disease. There were also a tendency to increase in basal serum gastrin concentration in HP positive patients. We suggest that antral HP increases antral gastrin release and gastric secretion. Increased acid secretion then causes duodenal ulcers by producing a low intraduodenal pH.

Adult↗

PubMed1991

[An experimental study on cerebral arteriosclerosis].

The experimental study suggested that it would be difficult to induce atherosclerosis in the cerebral arteries. Although the atherosclerotic lesions on the aortas were evident in the experimental rabbits of the hypertension plus hypercholesterolemia group, evidence of early atherosclerosis was found on the intracranial small arteries in only three out of the 10 rabbits of this group. Under the microscope widespread thickening and contraction were seen on almost all the small cerebral and cerebral parenchymal arteries. Hyaline degeneration could be seen in some of the arteries. Most of the cerebral parenchymal capillary endothelia were swollen and some of these cells contained lipid drops. All of these pathological changes could not be found in the authors earlier experiment in the group of the rabbits without hypertension. It was, therefore, surmised that both hypertension and hyperlipidemia would be two of the important factors in inducing the lesions in the cerebral arteries, but although such factors would be coordinative, hypertension might be more important in the process of damaging the cerebral arteries and leading to their degenerative changes.

Animals↗

PubMed1990

Pancreastatin: characterization of biological activity.

Pancreastatin (PST) (1-49) was first isolated from the porcine pancreas and can inhibit glucose-induced insulin release. PST (33-49), a PST C-terminal fragment, can also inhibit insulin release. The purpose of this study was to determine the shortest C-terminal biologically active fragment of PST, in terms of inhibition of insulin release from the isolated perfused rat pancreas. Porcine PST (1-49) and C-terminal fragments, PST (33-49), PST (35-49), PST (37-49) and PST (39-49) were synthesized by solid-phase methodology. PST (1-49), PST (33-49) and PST (35-49), at 10 nM, significantly (p less than 0.05) inhibited insulin release from isolated perfused rat pancreas: the first phase was inhibited by 15.6 +/- 2.4, 24.4 +/- 6.5 and 12.5 +/- 1.9% and the second phase, 18.9 +/- 2.7, 25.7 +/- 4.8 and 20.1 +/- 1.9% by PST (1-49), PST (33-49) and PST (35-49), respectively. PST (35-49) shows a dose-dependent inhibition of insulin release. PST (37-49) and PST (39-49) were, however, inactive. Our results indicate that the shortest C-terminal biologically active fragment is PST (35-49). These data further indicate that the C-terminal portion of PST is primarily responsible for the biological activity of PST.

Animals↗

PubMed1990

Morphological evidence for neuronal regulation of luteinizing hormone-releasing hormone-containing neurons by neuropeptide Y in the rat septo-preoptic area.

Using a preembedding double immunolabeling technique, synaptic contacts were found between luteinizing hormone-releasing hormone (LHRH)-containing neurons and neuropeptide Y-containing axonal fibers in the rat septo-preoptic area. In demonstrating LHRH neurons, we used mainly an antiserum generated against rat gonadotrophic hormone-releasing hormone-associated peptide. Although many diaminobenzidine-labeled neuropeptide Y-containing fibers were seen around silver-gold-labeled LHRH cell bodies, synapses with synaptic membrane specialization were scarce. The fiber terminals usually contained many small clear vesicles and some large cored vesicles. The synapses were characterized with the presynaptic accumulation of the small clear vesicles and symmetric thickenings of the synaptic membranes.

Animals↗

PubMed1990

Is obesity-related hypertension less of a cardiovascular risk? The Framingham Study.

The hypothesis that obesity-related hypertension is relatively innocuous was explored by an examination of cardiovascular events over 34 years of follow-up when related to biennially measured weights and blood pressures using time-dependent covariate proportional hazards analysis. The 5209 participants were also classified by age, cigarette smoking, and antihypertensive treatment at each of four baseline examinations with 8-year follow-up periods. Over the period of follow-up, there were 978 cardiovascular events in men and 836 in women. Risk of cardiovascular morbidity and mortality in general and of CHD in particular was as strongly related to hypertension at all levels of body mass index. This was also found to apply when adjustment was made for possible confounding by cigarette smoking. Age and smoking-adjusted absolute risks of cardiovascular events were found to be higher in hypertensive individuals with high than with low BMIs. Furthermore, the relative risk of cardiovascular disease did not vary significantly with BMI. Thus hypertension is at least as dangerous in obese as in lean persons at all ages in either sex, providing no support for the hypothesis that hypertension in the obese is more benign. This is important, since obesity predisposes to hypertension and most who have hypertension are obese. This report examines the hypothesis for CVD outcomes considered by previous reports and also the subcategories of CVD disease such as myocardial infarction and stroke, and includes data on both men and women and on young and old.

Adult↗

PubMed1990

Centrosome duplication continues in cycloheximide-treated Xenopus blastulae in the absence of a detectable cell cycle.

Cycloheximide (500 micrograms/ml) rapidly arrests cleavage, spindle assembly, and cycles of an M-phase-specific histone kinase in early Xenopus blastulae. 2 h after cycloheximide addition, most cells contained two microtubule asters radiating from perinuclear microtubule organizing centers (MTOCs). In contrast, blastomeres treated with cycloheximide for longer periods (3-6 h) contained numerous microtubule asters and MTOCs. Immunofluorescence with an anticentrosome serum and EM demonstrated that the MTOCs in cycloheximide-treated cells were typical centrosomes, containing centrioles and pericentriolar material. We conclude that centrosome duplication continues in cycloheximide-treated Xenopus blastulae in the absence of a detectable cell cycle. In addition, these observations suggest that Xenopus embryos contain sufficient material to assemble 1,000-2,000 centrosomes in the absence of normal protein synthesis.

Animals↗

PubMed1990

Gonadotropin-releasing hormone-associated peptide immunoreactivity in bovine colostrum.

Gonadotropin-releasing hormone(GnRH)-associated peptide (GAP) is a 56-amino acid peptide found on the C-terminal of the GnRH (also called luteinizing hormone-releasing hormone) precursor and is assumed to be co-produced with GnRH. The purpose of this report is to demonstrate the presence of GAP immunoreactivity in bovine colostrum. Radioimmunoassay of acidified methanolic extracts demonstrated a concentration of GAP immunoreactivity of approximately 1.5 +/- 0.1 pmol/g dry skim bovine colostrum. Gel filtration (Sephadex G-10) and high-performance liquid chromatography of extracts containing GAP immunoreactivity showed it to be of low molecular weight and a high hydrophobic character. The presence of GAP immunoreactivity in bovine colostrum suggests that the GnRH precursor is synthesized and processed in mammary tissue itself.

Animals↗

PubMed1990

[Relation of capsaicin-sensitive neurones to the effect of electro-acupuncture analgesia].

In this experiment, the rats treated with capsaicin (50 mg/kg) s. c. on day 2 of liqe were used 12 weeks after injection. The levels of substance P(SP) in sciatic nerves and dorsal spinal cords were measured with radioimmunoassay to evaluate the extent of C-afferent fibers damaged by capsaicin. The results as follows: (1) the levels of SP in the sciatic nerve and the dorsal spinal cord are decreased by 69% and by 62% respectively, indicating the degeneration of the primary C-afferent fibers is very massive; (2) the average of basal tail-flick latency (immersing in 50 degrees C water) is prolonged 105% as compared with the control; (3) after electro-acupuncture, the average of tail-flick latency of the capsaicin treated rats is increased by 81%, while that of the vehicle treated rats increased by 54%. These data suggest that C-afferent fibers substantially mediate the transmission of noxious thermal stimuli, but is unnecessary for the transmission of acupuncture message to induce analgesia.

Acupuncture Analgesia↗

PubMed1990

Some introductory remarks on acupuncture in dentistry.

In general two different types of acupuncture are used in dentistry, Traditional Chinese Acupuncture and Acupuncture according to Dr. Voll. Both use imaginary lines, called channels, according to theories of Traditional Chinese Medicine. However fundamental differences between the two types of acupuncture exist.

Acupuncture Therapy↗

PubMed1990

[Idiopathic inflammation of the optic nerve simulating optic nerve sheath meningioma].

A case of idiopathic inflammation of the optic nerve (perioptic neuritis) which simulated optic nerve sheath meningioma is reported and the literature reviewed. In this case, idiopathic inflammation of the optic nerve caused enlargement of the nerve and its sheath, showing a tubular diffuse thickening with a central hypodense area (tram-tracking sign). thus mimickling the cancers morphology idiopathic perioptic neuritis is an important condition for, the differential diagnosis of visual loss when CT demonstrates enlargement of the optic nerve.

Cranial Nerve Neoplasms↗

PubMed1990

[Computed tomographic findings of intracranial gliosis: report of 2 cases].

Two cases of intracranial gliosis documented by surgery and histopathology are presented. Intracranial gliosis is a nonspecific reaction to different neoplastic and non-neoplastic lesions. The CT findings were also non-specific and the disease could not be differentiated from other neoplastic and non-neoplastic lesions. The clinician and radiologist should be aware that in patients with intracranial gliosis of unknown etiology, clinical and CT follow-up studies should be done diligently in order to uncover the underlying pathology.

Adult↗

PubMed1990

[Anti-ulcer effects of weiteling tablets].

The traditional Chinese medicine Weiteling Pain shows a marked anti-ulcer action when administered orally at a dose of 3g/kg. The drug has been found able to inhibit the formation of stress restraint induced ulcer and reserpine induced ulcer. A decrease of volume of gastric juice collected from pyloric ligated stomachs and a reduced level of gastric acid have also been observed. In addition, the drug can reduce the inflammatory reaction of the acute gastritis induced by salicylate.

Animals↗

PubMed1990

[Studies on the structure of scuteamoenin from the root of Scutellaria amoena].

In containing our studies on the flavonoids from Scutellaria amoena C.H. Wright, a new flavanone (I) and six known compounds (II-VII) were isolated from the roots of this plant. On the basis of spectroscopic analysis (UV, 1H NMR, 13C NMR, MS and CD) and chemical evidence, the structure of the new compound was elucidated as (2S) -2',5,6'-trihydroxy-7-methoxyflavanone (I) and named scuteamoenin, the other six known compounds were identified as (2R,3R) -3,5,7-trihydroxyflavanone (II), 2',3,5,6,7-pentahydroxyflavone (III), 2',5,7-trihydroxy-6-methoxyflavone (IV), skullcaflavone II (V), chrysin (VI) and beta-sitosterol (VII) respectively. Compounds II-VII were obtained from this plant for the first time.

Drugs, Chinese Herbal↗

PubMed1989

Recent advances in brain-gut hormones.

Although recent advances in gene technology have made it possible to produce peptides and proteins by the recombinant technique, chemical synthesis either by the solution or by the solid-phase technique is still only a method of choice for the syntheses of a brain-gut hormone and its superagonist and/or antagonist. In addition, synthetic replicates of brain-gut hormones, their analogus and fragments or their precursor-related peptides are important haptenic immunogens to produce region-specific antisera to the respective peptides. In the present study, antisera against proglucagon and pro-LH-RH related peptides were proved to be useful not only for identifying hormone-producing cells, but also for demonstrating the post-translational biosynthetic processing in the cells. For galanin, a novel brain-gut hormone, have structural similarity in its C-terminal region to tachykinins, a monoclonal antibody against synthetic porcine galanin (1-15) was prepared for immunohistochemical study. This monoclonal antibody was found to recognize specifically galanin-producing cells and not to cross-react with any of tachykinins examined. These observations indicate that monoclonal antibodies are highly useful for identifying cells possessing a brain-gut hormone containing structures common to those of different known peptides.

Animals↗

PubMed1989