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Biomedical subjects

K Honda

Publications and source records attributed to K Honda.

At least 559 records · Page 31Linked to original sources
PubMed1988

[Effects of TJ-41 (Tsumura Hochu-ekki-to) on spermatogenic disorders in mice under current treatment with adriamycin].

Experiments were performed to investigate the effects of TJ-41 on spermatogenic disorders under current treatment with adriamycin (ADR). Male ICR mice were intraperitoneally injected with ADR at the dose of 0.15 mg/kg, twice a week for 5 weeks. Simultaneously, these mice were orally administered TJ-41 at the dose of 1, 2 or 4 g/kg for 12 weeks. The effects of TJ-41 were evaluated by histological analysis of germ cells in the testis at 7 weeks after the last injection of ADR. TJ-41 at a dose of 4 g/kg significantly inhibited the decrease of testis weight in mice treated with ADR. TJ-41 at doses of 1 and 4 g/kg significantly decreased the proportion of seminiferous tubules without germ cells as compared with the ADR-treated group. On the other hand, TJ-41 at doses of 1 and 4 g/kg significantly increased the proportion of normal seminiferous tubules and the Sertoli cell ratio of spermatocytes as compared with the ADR-treated group. These results indicate that TJ-41 may qualitatively and quantitatively protect against the decrease of germ cells in the testis of mice treated with ADR.

Animals↗
PubMed1988

Reduced oxytocin response to osmotic stimulus and immobilization stress in lactating rats.

The release of oxytocin in response to an osmotic stimulus and immobilization stress was compared in lactating rats 8-12 days after delivery and in non-lactating rats. Intravenous injection of hypertonic saline or immobilization stress induced an increase in blood oxytocin levels in both lactating and non-lactating rats, but the increment in the former was significantly lower than that in the latter. The lower responsiveness of oxytocin release to stress in lactating rats was not altered by ovariectomy 2 days after parturition. Oxytocin release induced by electrical stimulation of the anteroventral third ventricle (an osmoreceptive area), paraventricular nucleus and neurohypophysis was significantly lower, to a similar extent, in lactating rats compared with non-lactating rats. These findings indicate that the structural reorganization reported in the hypothalamo-neurohypophysial system may not function to facilitate release of oxytocin in response to stress and osmotic stimulus in lactating rats. The reduced responsiveness of the release of oxytocin is independent of the influence of ovarian hormones, and may be due to the low ability of the oxytocin neurone itself to release oxytocin, and/or due to the activated inhibitory influence on the oxytocin neurone in the lactating rat.

Animals↗
PubMed1988

Immunocytochemical study of Onuf's nucleus in amyotrophic lateral sclerosis.

The sacral segments of the spinal cord in 15 cases of amyotrophic lateral sclerosis and 7 control cases were investigated using peptides immunocytochemistry. A rich supply of somatostatin-, enkephalin- and substance P-immunoreactive fibers and terminals were found in common with the intermediolateral cell column in Onuf's nucleus, but not with the motor neurons in ventral horn. Furthermore, there was no significant difference with peptides innervation between ALS and control cases. Onuf's nucleus, though located in the ventral horn of the upper sacral segment, has a rich supply of peptidergic innervation which suggests that this nucleus does not represent merely somatic motor neurons, but also represents autonomic neurons. This may be related to sparing of Onuf's nucleus along with the autonomic sacral intermediolateral nucleus in ALS.

Adult↗
PubMed1988

Osmoreceptor mechanism for oxytocin release in the rat.

In order to determine whether oxytocin release is controlled by an osmoreceptor mechanism identical with that for vasopressin release, the plasma oxytocin concentration and plasma osmolality were measured during intraatrial infusion and after intraventricular injection of various osmotic solutions in unanesthetized rats. Intraatrial infusion of 0.6 M NaCl Locke solution (L.S.) or 1.2 M mannitol L.S. elevated plasma oxytocin significantly, while 1.2 M urea L.S. caused only a small increase and isotonic L.S. did not change in plasma oxytocin. All hypertonic solutions produced significant and similar increases in the plasma osmolality. Plasma oxytocin was positively correlated with plasma osmolality in the animals infused with hypertonic NaCl or mannitol but not in the animals infused with hypertonic urea. The injection of 2 microliters of 0.6 M NaCl artificial cerebrospinal fluid (CSF) or 1.2 M mannitol CSF into the third ventricle caused a significant increase in plasma oxytocin immediately (5 min after injection) without changing plasma osmolality, while the intraventricular injection of 1.2 M urea CSF or isotonic CSF produced no significant change in plasma oxytocin. These results indicate that oxytocin release is controlled by osmoreceptors rather than Na receptors, that the adequate stimulus for the osmoreceptors is one which produces cellular dehydration and that the osmoreceptors are located in the brain region which is accessible to osmotic agents from both the outside and inside of the blood-brain barrier. Since the organum vasculosum of the lamina terminalis (OVLT) lacks a blood-brain barrier and is known to be involved in osmotic control of vasopressin release, a lesion was made in the anteroventral region of the third ventricle which encompasses the OVLT and the effect of hypertonic NaCl infusion on oxytocin release was examined. No significant increase in plasma oxytocin was observed after intraatrial infusion of 0.6 M NaCl L.S. in the lesioned rats. All of these findings lead to the conclusion that oxytocin release is under the control of osmoreceptors identical to those for vasopressin release.

Animals↗
PubMed1988

Otitis media with effusion and tubal tonsil (video).

Carbon dioxide laser surgery was performed on children aged 5 to 11 years, on whom either adenoidectomy or tonsilloadenoidectomy had been performed to restore their hearing. We examined 177 ears 18 to 24 months after surgery. Thirty ears (17%) were diagnosed as having otitis media with effusion. Analysis of the endoscopic findings revealed 51% marked tubal tonsil hypertrophy and 33% adenoid tissue hypertrophy. Subjects were operated upon in the dorsal position for a duration of point one second at an amplitude of 15 watts. Six months after surgery, most patients' hearing had returned to almost normal. The tympanograms which were taken 6 months after surgery showed good results in almost every case. Otitis media with effusion was found to have recurred in 3 ears. The effect of adenoidectomy is apparently dependent upon age, the size of adenoids, and the influence of allergies and sinusitis. Furthermore, our cases suggested that tubal tonsil hypertrophy was one of the factors found in recurrent otitis media with effusion in older children. It can thus be inferred that endoscopic examination of the postnasal space is recommended in children with recurrent otitis media with effusion after adenoidectomy, and that carbon dioxide laser surgery is a reliable therapeutic method in the topical treatment of this disease.

Adenoidectomy↗
PubMed1988

Sequence-defined dimer block synthesis from unprotected nucleoside.

mediates to synthesize the oligodeoxynucleotides have been synthesize otected nucleoside using morpholinophosphorditetrazolide. From these sequence-defined oligodeoxynucleotides were also synthesized. The gen is composed of following steps; a) reaction of 5'-O-protected nucleo orpholinophosphorditetrazolide (phosphitilation), b) reaction of the nucleoside phosphoramidite with the second nucleoside (condensation), ueous oxidation with t-BuOOH (oxidation). RE 1/hlp F2/cmt F3/ext F4/can F5/nxt F6/ins F7/up F8/dwn F9/fin

Indicators and Reagents↗
PubMed1987

Vaginal distension induces milk ejection-related burst of oxytocin neurones interacting with suckling stimuli in lactating rats.

Milk ejection-related bursts of action potentials recurred at fairly regular intervals during suckling in oxytocin cells of anesthetized lactating rats. Additional milk ejection-related bursts were frequently induced in response to vaginal distension. The latency for the induced response was 2.9 +/- 0.2 s and the size of the induced bursts was similar to that of spontaneous ones. When animals were not suckled, the burst was in no case induced by the stimulus. The findings indicate that the two afferent stimuli arising from the mammary gland and vagina can interact with each other in generating milk ejection-related bursts of oxytocin cells.

Action Potentials↗
PubMed1987

Further studies on (+/-)-YM-12617, a potent and selective alpha 1-adrenoceptor antagonist and its individual optical enantiomers.

YM-12617, 5-[2-[[2-(o-ethoxyphenoxy)ethyl]amino]propyl]- 2-methoxybenzenesulfonamide HCl is structurally novel, an extremely potent and highly selective alpha 1-adrenoceptor antagonist. An asymmetric center exists at the alpha-carbon atom in the phenethylamine portion of YM-12617, therefore two optical enantiomers exist. alpha-Adrenoceptor blocking properties and hypotensive activities of YM-12617 and its enantiomers have been compared in vitro and in vivo. 1. In the isolated rabbit aorta, R(-)- and S(+)-YM-12617 competitively antagonized phenylephrine-induced contraction with pA2 values of 9.95 and 7.69, respectively. Although R(-)- and S(+)-YM-12617 were also competitive antagonists toward UK-14,304 at prejunctional alpha 2-adrenoceptors in the isolated guinea-pig ileum, the affinities of R(-)-YM-12617 (pA2 = 6.18) and S(+)-YM-12617 (pA2 = 5.64) for these receptors were 5,900 and 110 times lower than those displayed for postjunctional alpha 1-adrenoceptors in the isolated rabbit aorta. 2. R(-)- and S(+)-YM-12617 displaced both 3H-prazosin and 3H-idazoxan binding to rat brain membranes; however, the affinities of the R(-)- and S(+)-enantiomers for alpha 1-adrenoceptors (pKi = 9.95 and 7.83, respectively) were 21,000 and 72 times higher than those for alpha 2-adrenoceptors (pKi = 5.62 and 5.97), respectively. 3. Based on pA2 values obtained in the isolated tissues and pKi values in the binding assays, R(-)-YM-12617 was 132-182 times more potent than S(+)-YM-12617 as an antagonist at alpha 1-adrenoceptors. In contrast, the R(-)- and S(+)-enantiomers were similar in potency at blocking alpha 2-adrenoceptors.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic alpha-Antagonists↗
PubMed1987

Facilitation of milk ejection-related activation of oxytocin-secreting neurones by osmotic stimulation in the rat.

Extracellular recordings were made from antidromically identified neurosecretory cells in the paraventricular nucleus of the hypothalamus in urethane-anesthetized lactating rats. Sixty-six percent of the rats tested (n = 80) showed reflex milk ejections during suckling. Oxytocin neurones could be distinguished from other neurosecretory neurones by a characteristic high-frequency burst of spikes displayed before a reflex milk ejection. Twenty-three of the oxytocin neurones recorded from twenty-three individual animals were tested for the effect of intraperitoneal injection of 1.5 M NaCl (1 ml), which raised the plasma osmotic pressure from 299.3 +/- 2.4 (SE) mosmole/kg to 313.0 +/- 2.4 mosmole/kg. The injection significantly increased not only the firing rate of the oxytocin neurones (from 1.7 +/- 0.3 spikes/s to 4.9 +/- 0.6 spikes/s) but also the number of spikes per burst (from 53.6 +/- 7.4 to 75.5 +/- 7.5) and burst duration (from 3.38 +/- 0.22 s to 3.80 +/- 0.18 s). The amplitude of reflex milk ejection was also increased to 1.9 times. However, the injection did not change the interval between bursts. On the other hand, intraperitoneal injection of 0.15 M NaCl affected neither these parameters of oxytocin neurones nor the amplitude of milk ejection. Some of the antidromically identified neurones recorded in the rats which showed no detectable reflex milk ejection during suckling displayed intermittent bursts of action potentials. Ten of these neurones in ten individual rats were tested for the effect of 1.5 M NaCl. The number of spikes per burst was significantly increased and reflex milk ejection was induced by the injection in eight of these rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Action Potentials↗