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Biomedical subjects

J Su

Publications and source records attributed to J Su.

137 records · Page 8Linked to original sources
PubMed1992

Effect of dizocilpine maleate on cerebral anoxia and ischemic damage in rodents.

The Protective effects of dizocilpine maleate (DM) against anoxia in mice and ischemic damage in rats of 4-vessel occlusion (4-VO) were studied. DM 0.5 or 1.0 mg.kg-1 ip significantly prolonged the survival time of mice in closed containers. DM 0.5 and 1.0 mg.kg-1 ip 30 min prior to 4-VO obviously accelerated the electroencephalographic recovery, reduced the neuronal loss in the hippocampus, and increased the survival rate after 72-h reperfusion. These effects followed a dose-dependent manner. Our results indicate that selective non-competitive N-methyl-D-aspartate receptor blocker DM protects against anoxic and ischemic cerebral damage.

Animals↗
PubMed1984

Beneficial effect of anisodamine in hemorrhagic shock.

Anisodamine , an alkaloid extracted from Anisodus tanguticus , is widely used in China in the treatment of septic shock, but its mechanism of action is unknown. We studied its antishock action in cats in a well controlled model of hemorrhagic shock. A bolus dose of 1 mg/kg was given intravenously 20 min after MABP was stabilized at 40-45 mm Hg, followed by i.v. infusion of 2 mg/kg/h during the oligemic period. Two hours post-reinfusion, MABP was significantly higher (106 +/- 10 mm Hg) in the drug-treated group than in shock cats receiving only vehicle (53 +/- 6 mm Hg, P less than 0.001). Anisodamine treated shock cats exhibited significantly lower cathepsin D activity (P less than 0.02) and amino-nitrogen concentration (P less than 0.001) than untreated shock animals. Plasma myocardial depressant factor (MDF) activity was significantly increased in the untreated shock cats (61 +/- 6 Units/ml), but the plasma accumulation of MDF was significantly blunted by anisodamine (32 +/- 5 Units/ml, P less than 0.01). Anisodamine did not increase superior mesenteric artery flow ( SMAF ) in this model of hemorrhagic shock as there was no significant difference in SMAF between the two shocked groups. Thus, the beneficial effect of anisodamine probably is not due to vasodilation of the splanchnic vasculature. In vitro analysis indicates that the drug has a direct anti-proteolytic action in cat pancreatic homogenates. This may partly explain the mechanism of its action, which appears to be complex.

Animals↗
PubMed1984

Hormonal control of eclosion of flies from the puparium.

Pharate flies (Sarcophaga bullata) very close to eclosion were injected with hemolymph from eclosing flies or various other preparations, kept at 10 degrees C for 24 hr, returned to room temperature, and tested for eclosion behavior (ongoing, attempted, or completed eclosion) during the first 30 min, the subsequent 2(1/2) hr, and after 51 hr. Flies injected with "eclosion" hemolymph showed significantly more eclosion activity during the first 30 min than noninjected controls, flies injected with hemolymph from larvae, or flies injected with Ringer solution.

Journal Article↗
PubMed1982

Influence of sulpiride-induced hyperprolactinemia on baboon menstrual cycles: a longitudinal study.

The influence of sulpiride-induced hyperprolactinemia on the hypothalamic-pituitary-ovarian function of the baboon (Papio cynocephalus) was investigated. Plasma levels of prolactin, LH, FSH, estrone, estradiol, 17-hydroxyprogesterone, progesterone and 20 alpha-dihydroprogesterone in control and consecutive treatment cycles (sulpiride i.m. injections 100 mg/day) were determined serially. The hormonal changes indicate that the ovary is the most sensitive site to the direct inhibitory action of sulpiride-induced hyperprolactinemia.

Animals↗
PubMedDate not supplied

Morphological and biochemical assessment of DNA damage and apoptosis in Down syndrome and Alzheimer disease, and effect of postmortem tissue archival on TUNEL.

We have previously shown that Alzheimer disease (AD) brain exhibits terminal deoxynucleotidyl transferase dUTP nick end-labeling (TUNEL) for DNA damage and morphological evidence for apoptosis. Down syndrome (DS) is a neurodegenerative disorder that exhibits significant neuropathological parallels with AD. In accordance with these parallels and the need to clarify the mechanism of cell death in DS and AD, we investigated two principal issues in the present study. First, we investigated the hypothesis that TUNEL labeling for DNA damage and morphological evidence for apoptosis is also present in the DS brain. All DS cases employed had a neuropathological diagnosis of AD. Analysis of these cases showed that DS brain exhibits a significant increase in the number of TUNEL-labeled nuclei relative to controls matched for age, Postmortem Delay, and Archival Length, and that a subset of TUNEL-positive nuclei exhibits apoptotic morphologies. We also report that Archival Length in 10% formalin can significantly affect TUNEL labeling in postmortem human brain, and therefore, that Archival Length must be controlled for as a variable in this type of study. Second, we investigated whether biochemical evidence for the mechanism of cell death in DS and AD could be detected. To address this question we employed pulsed-field gel electrophoresis (PFGE) as a sensitive method to evaluate DNA integrity. Although apoptotic oligonucleosomal laddering has not previously been observed in AD, PFGE of DNA from control, DS and AD brain in the present study revealed evidence of high molecular weight DNA fragmentation indicative of apoptosis. This represents biochemical support for an apoptotic mechanism of cell death in DS and AD.

Adult↗
PubMedDate not supplied

The nontoxic tripeptide glycyl-prolyl-glycine amide inhibits the replication of human immunodeficiency virus type 1.

OBJECTIVE: To determine whether short peptides corresponding to the RGPGR motif of the V3 loop of gp 120 have anti-human immunodeficiency virus type 1 (anti-HIV-1) activity. DESIGN/METHODS: Short peptides were tested against the HIV-1 laboratory strains and clinical isolates. RESULTS: The tripeptide glycyl-prolyl-glycine amide (GPG-NH2) inhibited the replication of both laboratory strains and 47 clinical isolates, including 19 strains that were resistant to other drugs or that were from patients with failing therapy. The 50% inhibitory concentrations values were 2.7 to 37 microM. Phenotypic change of two isolates from nonsyncytia-inducing to syncytia-inducing did not change their sensitivity to GPG-NH2. The tripeptide added to the antiviral effect of both zidovudine and ritonavir. CONCLUSIONS: The tripeptide GPG-NH2 is a nontoxic compound that inhibits the replication of HIV-1 by an apparently new mode of action. Glycyl-prolyl-glycine-NH2 might prove useful by itself or as a lead compound for the treatment of drug-resistant HIV-1. Glycyl-prolyl-glycine-NH2 is currently undergoing phase I/II human clinical trials in Sweden.

Amides↗
PubMedDate not supplied

The tripeptide glycyl-prolyl-glycine amide does not affect the early steps of the human immunodeficiency virus type 1 replication.

OBJECTIVE: To determine whether the peptide glycyl-prolyl-glycine amide (GPG-NH2) corresponding to a conserved motif in the tip of the third hypervariable region of gp120 affected the early events in the human immunodeficiency virus type 1 (HIV-1) replication. DESIGN/METHODS: Glycyl-prolyl-glycine amide was tested for its effect on HIV-1 adsorption, co-receptor usage, proviral DNA synthesis, messenger RNA (mRNA) synthesis and splicing, translation, tat/TAR transactivation, and virus protease activity. RESULTS: Glycyl-prolyl-glycine amide did not appear to affect the early events of the virus replication. HIV-1 having glycine-leucine-glycine instead of GPG in the V3 loop and the mutants deleted of the GPG motif were still inhibited by the peptide. Glycyl-prolyl-glycine-NH2 had no discernible effect on any of the other steps in the virus replication cycle tested. The only effect observed was an increased sodium dodecyl sulfate polyacrylamide amide gel electrophoresis mobility of gp160/120 at high concentrations of GPG-NH2. CONCLUSIONS: The tripeptide GPG-NH2 is a nontoxic compound that inhibits the replication of HIV-1 by an apparently new mode of action.

Amides↗
PubMedDate not supplied

The effects of radiofrequency (< 30 MHz) radiation in humans.

121 workers who were exposed to RFR (< 30 MHz) over one year were examined. They were divided into two groups: one group was exposed to high electric field intensity (> or = 100 V/m), another to low intensity (< 100 V/m) and both groups were compared to control subjects. No significant changes in the functioning of the autonomic nervous system and blood parameters (Hb, WBC and blood platelets) occurred in the exposed subjects of either group. Some changes in ECG (ST-T interval and abnormal heart rate) were observed in the group exposed to high intensity (> or = 100 V/m) radiation. 100 V/m is suggested as an exposure limit for RF (< 30 MHz) radiation.

Adult↗