Education, occupation, and Alzheimer's disease.
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Alzheimer Disease↗
Biomedical subjects
Z M Zhang
Publications and source records attributed to Z M Zhang.
An experimental study on somatostatin receptors in the brains of hepatic encephalopathy rats.
The present study was undertaken to evaluate the effect of somatostatin (SS) receptor, a brain-gut peptide receptor which is capable of inhibiting central neurons, on the pathogenesis of hepatic encephalopathy (HE). By means of radioligand binding assay, SS receptors in crude synaptosomal membrane of rat brains were investigated in a rat model of HE induced by partial hepatectomy following carbon tetrachloride intoxication and in controls. Binding to SS receptor was studied using 125 I-SS as radioligand. Scatchard analysis of binding data was linear, yielding a dissociation constant (Kd) of 3.99 +/- 0.22 nmol/L and a maximal binding capacity (Bmax) of 238 +/- 14.2 fmol/mg of protein in HE rats. Only increased Bmax values were observed (P < 0.005), while the Kd values were statistically unchanged (P > 0.50), in HE rats as compared with those in controls. The results suggest that the changes of SS receptors in brains play a significant role in the pathogenesis of HE. The mechanism of HE induced by the alterations of SS receptors in the brains was discussed in this paper.
Animals↗
[An experimental study on brain-gut peptide receptors in brains of rats with hepatic encephalopathy].
By means of radioligand binding assay, two brain-gut peptide, somatostatin (SS) and vasoactive intestinal peptide (VIP), receptors in crude synaptosomal membranes of brain were investigated in rats with hepatic encephalopathy (HE) and in controls. In HE rats and in controls, the maximal binding capacity (Bmax) were 238.0 +/- 14.2 and 200.0 +/- 11.3 fmol/mg of protein, the dissociation constant (Kd) was 3.99 +/- 0.22 and 3.89 +/- 0.34 nM respectively for SS receptors. The Bmax values of VIP receptors in HE rats and in controls were 9.56 +/- 0.29 and 10.92 +/- 0.44 fmol/mg of protein, the Kd values were 0.28 +/- 0.01 and 0.29 +/- 0.02 nM, respectively. Increased Bmax values of SS receptors (P < 0.005) and decreased Bmax values of VIP receptors (P < 0.002) were observed in HE rats as compared with those in controls. The results suggest that changes of brain-gut peptide receptors in brains play a significant role in the pathogenesis of HE.
Animals↗
[Vasoactive intestinal peptide receptors in the brains of hepatic encephalopathy rats].
We evaluated the effect of vasoactive intestinal peptide (VIP) receptor, a brain-gut peptide receptor, which is capable of exciting central neurons, on the pathogenesis of hepatic encephalopathy (HE). By means of radioligand binding assay, VIP receptors in crude synaptosomal membrane of rat brains were investigated in a rat model of HE induced by partial hepatectomy following carbon tetrachloride intoxication and in controls. A dissociation constant (Kd) was found 0.28 +/- 0.01 nmol/L and a maximal binding capacity (Bmax) 9.56 +/- 0.29 fmol/mg of protein in HE rats. Only decreased Bmax values were observed (P < 0.002) and the Kd values were statistically unchanged (P > 0.20) in HE rats as compared with in controls. The results suggest that the changes of VIP receptors in brains play a significant role in the pathogenesis of HE. The mechanism of HE induced by the alterations of VIP receptors in the brains was described.
Animals↗
[Experimental studies on peripheral-type benzodiazepine receptors in brain in rats with hepatic encephalopathy].
By means of radioligand binding assay, peripheral-type benzodiazepine receptors (PBR) in the telencephalon, diencephalon, brain stem and cerebellum, were investigated in a rat model with hepatic encephalopathy (HE). Binding to PBR was studied using [3H]PK11195 as radioligand. It was demonstrated that only densities (Bmax) of [3H]PK11195 binding to crude synaptosomal membranes in the telencephalon, diencephalon of HE rats were obviously increased as compared with those of controls (P < 0.001 and P < 0.05 respectively). Increased affinities (Kd) were only observed in brain stem (P < 0.05). The results showed that the alterations of PBR in different regions of the brain play a significant role in the pathogenesis of HE.
Animals↗
[Clinico-pathologic study of 285 cases of ectopic pregnancy in intrauterine devices-users and non-intrauterine devices-users].
Two hundred eighty five cases of ectopic pregnancy in Beijing area from Jan. 1 to Dec. 31 1990 including 150 cases of intrauterine devices (IUD) and 135 cases of non-IUD users were studied. Clinico-pathological observation included the history of pelvic inflammatory disease, the site of ectopic pregnancy, the classification of previous tubal inflammation of the ectopic side and other pathologic lesions, the side of the corpus luteum of pregnancy and histology of endometrium, etc. Besides, using stereologic technique the cilia length and cilia density of endosalpinx were studied in 50 cases through image analysis system. Results showed that except for a significant higher frequency of ovarian pregnancy in IUD-users, there was no significant differences between the 2 groups. It indicated that the degree of injury of fallopian tubes and the factors causing the damage were similar in both groups. The authors concluded that IUD does not increase the risk of fallopian tube lesions.
Fallopian Tubes↗
[Tuberculosis ulcer of the oral mucosa: Report of 3 cases]
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Journal Article↗
Experimental studies on central benzodiazepine receptors in the brains of hepatic encephalopathy rats.
With radioligand binding assay, we studied the central benzodiazepine receptors (CBR) in the different regions of brain including the telencephalon, diencephalon, brain stem and cerebellum in a rat model of hepatic encephalopathy (HE) induced by partial hepatectomy following carbon tetrachloride (CC1(4)) intoxication and in the controls. Affinities (Kd) and densities (Bmax) of [3H]-flunitrazepine binding to crude synaptic membranes in the telencephalon of HE rats were obviously increased as compared with those of the controls. It was only in the diencephalon, the brain stem and the cerebellum of HE rats that increased Bmax values were observed, while the Kd values remained unchanged. The results support the recent suggestion that the alterations of CBR play a significant role in the pathogenesis of HE. Among the ranges of the alterations of CBR in the HE rats, the telencephalon ranked first, the brain stem second, the cerebellum third, and the diencephalon last.
Animals↗
Purification and cloning of opioid receptors.
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Animals↗
[Incidence of ectopic pregnancy in Beijing area].
The incidence of ectopic pregnancy (EP) was studied through the 3 level monitoring network of maternal and child health care (MCH) in the whole Beijing area, including 82 hospitals, 19 MCH centers and 2 institutes for family planning. 1,420 cases of EP were collected in a sample of 2.7 million women of reproductive age (15-49) during one year period from January 1 to December 31 1990. The cases were confirmed by pathological examination or laparoscopy, and method of epidemiological surveillance was used. The results showed that the overall incidence of EP was 0.52 per thousand women of reproductive age in Beijing area, 0.60/1,000 in urban districts and 0.41/1,000 in rural area; 0.67/1,000 in married women, and 0.05/1,000 in the unmarried; for married women the incidence was 0.54/1,000 in women using various contraceptive measures and 1.80/1,000 in women using no contraceptive methods, while women after sterilization had the lowest incidence (0.18/1,000) and women using natural contraceptive measures (rhythm or withdrawal method) had the highest (2.43/1,000). It was 0.65/1,000 in IUD users, 0.21/1,000 in OC users and 0.57/1,000 in couples using condom or spermicides. The ratio of EP to delivery was 1:90 or 11.41/1,000 delivery.
Adult↗
Effect of hypoxia on the accumulation of technetium-99m-glucarate and technetium-99m-gluconate by Chinese hamster ovary cells in vitro.
The accumulation of 99mTc-glucarate, an agent recently reported to localize in acutely infarcted myocardium, zones of acute cerebral injury and tumors, has been compared with 99mTc-gluconate in an in vitro system of cultured Chinese hamster ovary fibroblasts. The effects on accumulation of hypoxia and competition with fructose have been studied. Both labeled glucose analogs showed a two- to threefold enhanced accumulation in hypoxic cells relative to aerobic cells. No such enhanced accumulation under hypoxia was observed for the nonsugar tracers pertechnetate and 99mTc-DTPA. The presence of 20 mM fructose reduced the accumulation of 99mTc-glucarate by 30% (p = 0.067) and 99mTc-gluconate by 40% (p < 0.05) in hypoxic cells, but had no significant effect in aerobic cells. These results suggest that both compounds at least partially share a common mechanism of uptake and/or accumulation with fructose.
Animals↗
Formulation of technetium-99m-aerosol colloid with improved delivery efficiency for lung ventilation imaging.
Static imaging of lung ventilation in multiple views or with SPECT requires a 99mTc aerosol which does not wash out during imaging. Commercially available 99mTc colloids have suitable physical properties but are inefficiently delivered from jet nebulizers. An in vitro system was used to compare the delivery of various 99mTc radiopharmaceuticals from nebulizer solutions. Delivery of noncolloidal agents (pertechnetate, pentetate, imidodiphosphate, albumin) was much greater than that of colloids. However, addition of phosphate buffer to an in-house 99mTc-tin colloid produced an agent that was delivered as efficiently as the noncolloidal tracers and which shows promise for clinical use.
Aerosols↗
Purification of opioid receptor in the presence of sodium ions.
Opioid receptor was solubilized from rat brain membranes with a mixture of the detergents CHAPS and digitonin in the presence of protease inhibitors and 1 M NaCl. The solubilized receptor bound mu-opioid agonists and antagonists with affinities similar to those of native membrane receptor. The affinity of solubilized receptor for the agonist PL017 was greatly reduced by GTP gamma S, suggesting the receptor is still associated with G-protein. The solubilized material was passed through an opioid antagonist (10cd) affinity column and a wheat germ agglutinin column, set up in series, to obtain a partially purified receptor preparation. This partially purified material bound mu-agonist with low affinity and the binding affinity was no longer affected by GTP gamma S. The partially purified receptor was further purified by repeating the affinity and lectin chromatography with smaller size column. Binding of opioid antagonist [3H]diprenorphine to the partially or purified receptors was dependent upon the presence of sodium ions. The purified receptor showed saturable and stereospecific binding for opioid ligands, was predominantly of the mu-type, and exhibited as a diffuse band with a medium molecular mass of 62 kD upon sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The average specific binding activity of the purified receptor was 18.8 +/- 2.3 pmol/micrograms protein, a value close to the theoretical estimation.
Animals↗
Evaluation of reduction-mediated labelling of antibodies with technetium-99m.
Monoclonal antibodies can be labelled with technetium-99m by prereduction of the antibody with 2-mercaptoethanol, then reduction of pertechnetate with an aliquot of a stannous kit, resulting in greater than 97% labelling without the need for further purification. The present work shows that equally high labelling can be obtained with a variety of weak ligands and that the optimum quantity of stannous chloride is 2-4 micrograms. Although the label was stable to challenge with excess DTPA, cysteine was able to remove a portion of the label. We have also shown that this technique works with the IgG2a isotype in addition to the previously reported IgG1 isotype. This approach is simple, convenient and reproducible, and warrants further clinical evaluation.
Antibodies, Monoclonal↗
[Treatment of chronic gastritis with traditional Chinese medicine--yingwei tablet].
A prospective controlled study on the treatment of 60 cases chronic gastritis with TCM Yingwei tablet as well as Sucrafati and Doperidone tablets from Oct. 1990 to Sep. 1991 were done. 30 patients in each group. The cases in treated group took Yingwei tablet while that in control group took Sucrafati and Doperidone tablets. Before and after treatment, the patients were examined by gastroscope, pathology and Helicobacter pylori. The results showed that total effective rate, the gastroscopically effective rate, the pathological cure rate, the cure rate of gastric mucosa atrophy and the effective rate of bacteriocidal effect against Helicobacter pylori in treated group and control group was 96.7% and 73.3%; 80% and 70%; 36.7% and 20%; 38% and 9%; 60% and 23.0%, respectively, all of the above-mentioned differences between the two groups was significant (P < 0.05-0.01). Therefore Yingwei tablet is an effective drug for various kind of chronic gastritis.
Adult↗
Uptake of N-(4'-pyridoxyl)amines and release of amines by renal cells: a model for transporter-enhanced delivery of bioactive compounds.
The importing of vitamin B6 by renal proximal tubular cells from the rat is facilitated and Na(+)-dependent and reflects specificity for the meta-phenolate pyridinium structure with a 5-hydroxymethyl function. This transporter can, however, accept competitively each of the natural nonphosphorylated vitamers (pyridoxine, pyridoxamine, and pyridoxal) and other B6 analogues differing only in the groups at position 4. A series of N-(4'-pyridoxyl)amines was synthesized by sodium borohydride or boro[3H]hydride reduction of aldimines formed by condensing the amines with pyridoxal. The unlabeled B6-secondary amine compounds were found to competitively inhibit the uptake of [4'-3H]pyridoxine by the renal cells. Moreover, the 3H-labeled N-(4'-pyridoxyl)amines were shown to enter the cells by the process facilitated by the B6 transporter. Upon entry the labeled compounds were converted to N-(5'-phospho-4'-pyridoxyl)amines in a reaction catalyzed by pyridoxal kinase, an enzyme that tolerates considerable functional variation in position 4 of the B6 structure. The 5'-phosphates were subsequently converted within the cell to pyridoxal 5'-phosphate with liberation of the original amine in a reaction catalyzed by pyridoxamine (pyridoxine) 5'-phosphate oxidase, an enzyme with broad specificity for 4'-substituted amines on the 5'-phospho-B6 structure. This system illustrates how knowledge of transporter specificity can permit design of a compound with potential biologic activity. A drug or other intracellular effector may be piggybacked onto a transported solute (e.g., vitamin or other nutrient) that gains facilitated entry to a cell and is, thereafter, metabolized to release the active compound.
Amines↗
The AMPA receptor antagonist NBQX has antiparkinsonian effects in monoamine-depleted rats and MPTP-treated monkeys.
Abnormally increased subthalamic nucleus output to the internal pallidal segment and the reticular part of the substantia nigra plays a critical pathophysiological role in the development of parkinsonism. Because synaptic transmission of subthalamic output is glutamatergic and mediated, in part, by the alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA) subtype of glutamate receptor, AMPA receptor antagonists may possess antiparkinsonian properties. We report that in monoamine-depleted rats, 2,3-dihydroxy-6-nitro-7-sulfamoyl-benzo(f)quinoxaline (NBQX) (Novo-Nordisk, Copenhagen, Denmark)--a selective antagonist of the AMPA subtype of glutamate receptor--suppressed muscular rigidity but had no effect on akinesia. NBQX microinjected into the subthalamic nucleus, internal pallidal segment, and reticular part of the substantia nigra, but not into the laterodorsal neostriatum of the rats, stimulated locomotor activity and reduced muscular rigidity. In aged Rhesus monkeys with bilateral 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced parkinsonism, intramuscular NBQX produced clinically apparent improvement in akinesia, tremor, posture, and gross motor skills. NBQX also potentiated the antiparkinsonian effects of L-3,4-dihydroxyphenylalanine in both rats and monkeys. Blockade of excitatory synaptic transmission by AMPA receptor antagonists may provide a new therapeutic strategy for Parkinson's disease (PD).
Animals↗
Nasal secretion of iodine-131.
A case of total-body I-131 imaging showing an abnormal collection of I-131 is presented. The site of uptake was initially thought to be a thyroid carcinoma metastasis in the upper right thigh but was subsequently shown to be due to the nasal secretion of I-131 contaminating a handkerchief. Other possible causes of I-131 contaminated handkerchiefs are also discussed.
Humans↗