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Biomedical subjects

H Kuroda

Publications and source records attributed to H Kuroda.

At least 307 records · Page 17Linked to original sources
PubMed1986

[An analysis of prognostic examination in cirrhotic portal hypertension and hepatoma].

With an increasing number of patients with advanced liver cirrhosis, the discrepancy between the preoperative examination and results of surgery for bleeding varices is widening. To correct this discrepancy, additional prognostic examinations to Child's criteria and routine hepatic laboratory tests were studied in our 246 cirrhotic patients with esophageal varices. These included wedged hepatic vein pressure, clearance and maximal removal rate of indocyanine green, and hepaplastin test. We performed the endoscope assisted terminal esophagoproximal gastrectomy with the EEA stapler gun with devascularization and splenectomy. No operative death and complications developed when the results of following 4 preoperative examinations were: wedged hepatic vein pressure below 400 mm of saline, peripheral disappearance rate (K) of indocyanine green above 0.04 min-1, maximal removal rate (Rmax) of the dye above 0.3mg/kg/min and hepaplastin test more than 40%. It is necessary for these indicators to be satisfied simultaneously prior to performing this surgery. In addition, these values should be changed a little in their critical limits when these cirrhotic patients also had hepatoma and were candidates for hepatectomy.

Adult↗
PubMed1985

Effect of serum and 12-O-tetradecanoyl-phorbol-13-acetate on FSH-stimulated conversion of 4-androstene-3,17-dione to oestrogens in cell and organ cultures of suckling mouse ovaries.

The effect of serum and 12-O-tetradecanoylphorbol-13-acetate (TPA) on the FSH-stimulated oestrogen production was studied in both cell and organ cultures. Ovaries were removed from (WB X C57BL/6)F1 mice at 9-days of age, and the conversion of 4-androstene-3,17 -dione to oestrogens was stimulated by the addition of FSH in vitro. Either 10% serum (fetal calf, mouse, rat and horse) or 0.1 microM TPA markedly inhibited the FSH-stimulated oestrogen production by dispersed and cultured ovarian cells. In contrast, neither serum nor TPA influenced the oestrogen production in the organ culture. This suggests that the presence of tissue architecture may prevent the inhibitory effect of serum and TPA on the FSH-stimulated oestrogen production.

Androstenedione↗
PubMed1985

Treatment of stroke with opiate antagonists--effects of exogenous antagonists and dynorphin 1-13.

We studied the effects of acute and long-term, continuous administration of six opioid compounds--naloxone, naltrexone, diprenorphine, leucine enkephalin, dynorphin 1-13, and dynorphin 3-13--on neurologic function, survival, and infarct size in a feline model of acute focal cerebral ischemia. Acutely, naloxone, naltrexone, and diprenorphine significantly improved motor function over baseline scores; the other drugs and saline (control) had no effect. In the long-term condition, no substance administered significantly affected level of consciousness, sensory function, or pupillary reactions. Naloxone, naltrexone, and dynorphin 1-13 significantly prolonged survival (p less than 0.1); the other substances had no effect. Evaluations of cat brains postmortem showed that the infarcts involved the sensory and motor cortex, internal capsule, and caudate nucleus. Infarct size was unaltered by any treatment administered; results among groups were remarkably similar. In evaluations of opiate receptor binding characteristics, high-affinity binding of ekylketocyclozocine was significantly reduced in the right (occluded) side of the cortex. Dynorphin 1-13 given 8 h postocclusion but before sacrifice increased this binding affinity to the previous level in non-occluded cortex. The observed protective effect of dynorphin 1-13 warrants further investigation. Our results support the involvement of endogenous opioid peptides in the pathophysiology of cerebral ischemia and suggest that, administered appropriately, opiate antagonists may be useful in the treatment of focal ischemic neurologic deficits.

Acute Disease↗
PubMed1985

Urinary retention induced by estrogen injections in mice: an analytical model.

Daily subcutaneous injections of pharmacological doses of 17 beta-estradiol (E2, 0.4 micrograms./gm. body weight) resulted in significant urinary retention in the bladder of castrated mice. Although the urinary retention developed in both male and female mice, the increase in urethral resistance to urinary flow and the dilatation of posterior urethra were observed only in castrated male mice receiving E2. Histological changes common to male and female mice were cornification and stratification of urethral epithelium and fibrosis of connective tissues surrounding the urethra, suggesting that these changes may cause the urinary retention. Although the exact mechanism has not been defined, the urinary retention produced by the present method may be useful as a model of human disease.

Animals↗
PubMed1985

Specific epidermal growth factor receptors on porcine and human thyroid membranes.

Specific, high affinity, saturable receptors for epidermal growth factor (EGF) have been demonstrated both on porcine and on human thyroid membranes. The binding affinities of porcine (Ka 3.0 X 10(-9) M) and human thyroid EGF receptors (Ka 1.75 X 10(-9) M) are very similar. TSH does not inhibit the binding of 125I-EGF to either membrane. These results suggest the possibility that EGF may be involved in the regulation of human as well as porcine thyroid follicular cell growth and function.

Animals↗
PubMed1985

Forskolin stimulation of adenylate cyclase in human thyroid membranes.

Forskolin stimulates adenylate cyclase in human thyroid membranes approximately 7-fold with half-maximal stimulation occurring at 5-10 microM. Guanine nucleotides are not required for stimulation of the enzyme by forskolin. Forskolin-stimulation is additive or greater than additive with that of TSH or Gpp(NH)p- (above 1 microM). Different from TSH- or Gpp(NH)p-stimulation of adenylate cyclase, uncoupling of the guanine nucleotide-binding regulatory component by increasing concentrations of MnCl2 did not result in uncoupling of forskolin stimulation. The finding indicates that forskolin may mainly act on the catalytic component of adenylate cyclase. From the present study, it is suggested that the diterpene forskolin stimulates adenylate cyclase in human thyroid membranes by a novel mechanism that differs from TSH- or Gpp(NH)p-stimulation, and that the diterpene may be a useful tool to investigate the metabolism of thyroid and its regulation in normal and pathological situations.

Adenylyl Cyclases↗
PubMed1985

Effects of pentazocine and concomitant clonidine on opioid receptors in the rat brain.

The changes in opioid receptors (Op-R) caused by repeated administration of pentazocine and the effect of concomitant clonidine were investigated. Binding of [3H] naloxone was markedly decreased in the absence of Na+, but was increased in the presence of Na+ in the diencephalon-mesencephalon of chronic pentazocine-treated rats. No significant changes were observed in the cerebral cortex of pentazocine-treated rats. The pentazocine-induced changes in Op-R were abolished by the concurrent use of clonidine, an alpha-adrenergic agonist, which has been shown to relieve the withdrawal symptoms of morphine. This result indicated that the behavioral action of clonidine can also be observed at the Op-R level.

Animals↗
PubMed1985

Synthesis and antitumor activity of spergualin analogues. I. Chemical modification of 7-guanidino-3-hydroxyacyl moiety.

Many analogues and derivatives of an antitumor antibiotic, spergualin, were synthesized, and the relationships between the structure and the activity against mouse L-1210 tumor were studied. Both modification of the 15-hydroxyl group and alteration of chain-length of the omega-guanidinoacyl moiety affected the activity. 15-Deoxyspergualin (18, 1-amino-19-guanidino-11-hydroxy-4,9,12-triazanonadecane-10,13-d ion e) and its analogue 25 (1-amino-21-guanidino-11-hydroxy-4,9,12-triazauneicosane-10,13-dio ne) had strong activity, superior to that of spergualin.

Animals↗
PubMed1985

Influence of angiotensin-converting enzyme inhibitor, foroxymithine, on dynamic equilibrium around the renin-angiotensin system in vivo.

To understand the in vivo actions of angiotensin-converting enzyme (ACE) inhibitors, a prolonged study was performed in rabbits over a half year, using one of such inhibitors, foroxymithine. During the initial 2 months of the inhibitor administration, the serum level of ACE was suppressed. Thereafter, probably triggered by the consequent sharp rise in the plasma renin activity (PRA) level, the ACE level regained its initial value. Thus the close correlation between the levels of PRA and ACE seen in the control animal was entirely broken by this inhibitor. A multivariate study indicated that the inhibitor drastically changed the normal networks of peptide metabolism in vivo. These results are compatible with the notion that the ACE inhibitor blocks the regulatory mechanisms of the renin-angiotensin system in vivo.

Angiotensin I↗
PubMed1985

[An experimental study on the role of pancreatic hormones in the regeneration of the canine liver].

The role of pancreatic hormones on hepatic regeneration after partial hepatectomy was studied in dogs with a new portal blood flow diversion which did not use vein graft. Right lobe of the liver received blood from the pancreas, stomach, duodenum and spleen, whereas the left lobe received blood from the intestine. Venous anastomoses were patent in 70% of survival animals for 12 weeks. Right lobe of the liver, from which 10% of the whole liver weight was removed, revealed rapid accumulation of glycogen and weight in the early stage of regeneration but failed to show sufficient removal of indocyanine green (ICG). On the other hand, left lobe, from which 40% of the liver was removed, revealed a slow and steady regenerative process and maintained efficient ICG removal throughout the study. The results revealed that endogenous pancreatic hormones could be a transient stimulating factor in the early stage of hepatic regeneration but do not require supplementation.

Animals↗
PubMed1985

Uterotropic hormones produced by ovaries of Sl/Slt mutant mice before spontaneous development of tubular adenomas.

Tubular adenomas developed spontaneously in ovaries of (WB X C57BL/6)F1-Sl/Slt and -W/Wv mice after 150 days of age. The uteri of the W/Wv mice were hypoplastic before development of tubular adenomas, but the uteri of the Sl/Slt mice were not. Since oophorectomy significantly reduced the uterus weight in the Sl/Slt mice, we investigated the androgen- and estrogen-producing activity of Sl/Slt and W/Wv mice before development of tubular adenomas. Fragments of ovaries were cultured for 48 hr in serum-free medium containing either progesterone or 4-androstene-3,17-dione (androstenedione). The amount of androgens produced from progesterone by ovaries of Sl/Slt mice in the presence of human chorionic gonadotropin was comparable to that of W/Wv mice. In contrast, the amount of estrogens produced from androstenedione by ovaries of Sl/Slt mice in the presence of follicle stimulating hormone was much greater than that of W/Wv mice. Moreover, the amount of estrogens produced was much greater than the amount of androgens in the ovaries of Sl/Slt mice. Therefore, before development of tubular adenomas, estrogens rather than androgens seem to be a major uterotropic hormone produced by ovaries of Sl/Slt mice.

Adenoma↗