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Biomedical subjects

C R Hung

Publications and source records attributed to C R Hung.

At least 109 records · Page 6Linked to original sources
PubMed1984

Intraventricular arginine vasopressin maintains ethanol tolerance.

Tolerance to the hypnotic effect of ethanol in mice is prolonged by once daily intraventricular injections of arginine vasopressin. This action is similar to that reported previously when vasopressin was administered subcutaneously. The results indicate that maintenance of ethanol tolerance by vasopressin is a centrally mediated action of the peptide, and is not due to possible aversive properties of peripherally administered vasopressin.

Analysis of Variance↗
PubMed1984

Effect of manganese treatment on the levels of neurotransmitters, hormones, and neuropeptides: modulation by stress.

Six weeks of daily intraperitoneal injection with manganese chloride (15 mg/kg body wt) reduced the normal weight gain of male Fischer-344 rats. This treatment depressed plasma testosterone and corticosterone levels, but prolactin levels were unaffected. The only significant changes in the levels of a variety of neuropeptides assayed in several regions were increases in the levels of hypothalamic substance P and pituitary neurotensin. Striatal serotonin, dopamine, and their metabolites were unchanged in manganese-exposed rats relative to saline-injected controls. However, the stress of injection combined with the effect of manganese appeared to significantly increase concentrations of striatal monoamines relative to uninjected controls.

Animals↗
PubMed1984

Sternal splintage with rib graft to avoid retrosternal compression after open heart surgery--an experimental study.

We present an experimental study in monkeys of sternal splintage using single or multiple rib grafts. This technique provides an enlarged retrosternal space, at the same time giving good stability of the mediastinum. In this way it is possible to avoid compression of the dilated heart, an external conduit or an assist device as may happen on occasion after conventional sternal closure.

Animals↗
PubMed1982

The prevention of an artifact in receptor binding assay by an improved technique.

The intensity of vacuum suction used during filtration of cerebral membranes on glass fiber filters used in the assays of neurotransmitter receptors is a factor in determining the apparent extent of bound radioactivity. This is not related to protein loss during filtration at various speeds nor to rates of dissociation of various ligand-receptor complexes. It appears to be due to the failure of hydrophobic ligands on dry filters, to be readily removed by aqueous media. A means whereby the vacuum can be held constant is described and shown to eliminate this artifact.

Animals↗
PubMed1982

Lack of asymmetrical distribution of receptor binding sites and of neurally active peptides within rat brain.

The high affinity binding of 5 tritiated (naloxone, spiroperidol, serotonin, quinuclidinylbenzilate, dihydroalprenolol) ligands to left and right frontal cortex, hippocampus and striatum has been compared in 8-week-old male rats. No lateralization of specific binding was observed between paired brain regions. Also, no regional asymmetry of protein content was found. No significant differences in met-enkephalin and substance P contents were found between paired striata, frontal cortex, and hippocampi. These data suggest that several neurotransmitter and neuromodulator indices are symmetrically distributed within the rat brain.

Animals↗
PubMed1981

H+ back diffusion stimulating gastric mucosal blood flow in the rabbit fundus.

The effect of barrier breakers on gastric mucosal blood flow (MBF) has been disputed, but the influence of acid back diffusion alone has never been studied. In anesthetized New Zealand white rabbits, intramural pH (pHi) and gastric MBF were measured with an antimony microelectrode and with radioactive microspheres (51Cr, 85Cr, 141Ce), respectively. Innervated fundic pouches were perfused with solutions of varying [H+] at 37 degrees C. In the rabbit, back flux of H+ is linearly dependent on luminal [H+] and in the present studies a direct positive linear correlation was found between luminal [H+] and MBF (r = 0.97 P < 0.001) while pHi remained unchanged up to luminal [H+] of 80 mM. The usual 80% increase in MBF induced by 80 mM HCl was prevented by pretreatment with vasopressin, which decreased pHi and caused gross ulceration. Without vasopressin, [H+] of 120 mM HCl produced gross mucosal ulceration and a decrease in MBF and pHi. Our data suggest that back diffusion of H+ influences MBF in the rabbit. There is an increasing MBF caused by increasing luminal [H+] up to 80 mM, beyond which MBF decreases. When the balance between back diffusion and MBF is disturbed by a vasoconstrictor or a high luminal [H+], pHi decreases and gross ulceration occurs.

Animals↗
PubMed1980

Ruptured congenital aneurysm of the right sinus of Valsalva into the right ventricle: with special reference to pathoanatomic and hemodynamic characteristics in symptomless cases.

Clinical features of 19 cases with congenital aneurysm of the right sinus of Valsalva rupturing into the right ventricular outflow region (Type 1) were analysed in relation to their pathoanatomic lesions and hemodynamic alterations. Sixteen cases were operated with one surgical death. All were catheterized together with ascending aortographic study. Rupture of the aneurysm in many cases was silent or symptomless and progressive heart failure was not quite common. Symptomatology of the patients did not seem to be related entirely to status of the pathoanatomical lesions or hemodynamic alterations. Time of the rupture, and inherent right ventricular characteristics, tolerating volume overload rather well, might be, in part, responsible for its better prognosis in some cases. However, all patients with ruptured aneurysm of the sinus of Valsalva should be treated surgically. Bacterial endocarditis is a serious complication leading to death.

Adolescent↗