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Biomedical subjects

H Ohta

Publications and source records attributed to H Ohta.

At least 703 records · Page 39Linked to original sources
PubMed1986

[The effect of hyperoxemia on cerebral blood flow in normal humans].

The aim of this study was to evaluate the effect of various degrees of hyperoxemia on cerebral blood flow (CBF), including the hyperbaric oxygenation (HBO) environment. Study subjects were 28 healthy volunteers (17 males and 9 females) from 26 to 60 (average: 42 +/- 11) years old. CBF measurements were done by 19 mCi 133Xe intravenous injection method using rCBF analyzer BI-1400 (Valmet). Two-compartmental analysis was used for the calculation of Fast, Slow Flow and initial slope index (ISI). The three CBF study series included: Rest (before HBO 1 ATA.air)-1 ATA.O2-2 ATA.O2 series in 8 cases; Rest-1 ATA.O2 50% N2 50%-1.5 ATA.O2 series in 10 cases; and Rest-2.5 ATA.O2-after HBO (1 ATA.air) series in 8 cases. CBF measurements commenced 5 to 10 minutes after fixing a mask for oxygen inhalation. Arterial blood gas analyses using IL-813 (IL) and blood pressure measurements were done immediately after CBF measurements. CBF changes evaluated by ISI, estimating resting flow as 100% (PaO2: 93 +/- 8 mmHg), were 91% at 1 ATA.O2 50% (PaO2: 201 +/- 50 mmHg), 79% at 1 ATA.O2 (PaO2: 432 +/- 44 mmHg), 77% at 1.5 ATA.O2 (PaO2: 693 +/-79 mmHg) and 71% at 2 ATA.O2 (PaO2: 838 +/- 95 mmHg). CBF gradually decreased to the level shown for 2 ATA.O2, but CBF showed a tendency to increase somewhat at 2.5 ATA.O2 (81%, PaO2: 1103 +/- 111 mmHg). CBF decreases were statistically significant at 1 ATA.O2, 1.5 ATA.O2, 2 ATA.O2 and also 2.5 ATA.O2 compared with Rest (P less than 0.05). Arterial blood gas analyses clearly showed the stepwise increase in PaO2 to the level of 2.5 ATA.O2 (P less than 0.01). Changes in PaCO2 and blood pressure were slight and not significant statistically in each series. Since the data showed no significant change in the PaCO2 level in each series, it was concluded that the CBF decrease was due to vasoconstriction caused by the elevated PaO2. The mechanism of cerebral vasoconstriction caused by hyperoxemia is not yet clearly understood, but the direct vasoconstrictive effect of oxygen, neurogenic control and the metabolic effect of an elevated cerebral tissue oxygen level may contribute to the CBF decrease. CBF decrease during elevated PaO2 may be a protective physiological response to maintain normal brain metabolism and function against the excessive oxygen supply. Disturbance of this regulatory mechanism may result in oxygen poisoning of the central nervous system.(ABSTRACT TRUNCATED AT 400 WORDS)

Administration, Inhalation↗
PubMed1986

[A case of pineocytoma presenting with symptoms like normal pressure hydrocephalus].

A pineocytoma in an old man, whose initial symptoms resembled a normal pressure hydrocephalus, is reported. This 67-year-old man gradually became uncommunicative and difficult to walk alone in three months. Just before visiting our clinic, his family also noticed his nocturnal urinary incontinence. CT scan on admission disclosed tumor in the posterior wall of the third ventricle, and subsequent hydrocephalus. This oval, isodense tumor was homogeneously enhanced after the injection of contrast medium on CT scan. The vertebral angiography showed a mass in the pineal region with no vascular staining. Ventricular drainage, the opening pressure of which was 100 mmH2O, could not offer cytological verification of the tumor. By the infratentorial supracerebellar approach, the tumor was successfully extirpated, and the post-operative course was uneventful. The microscopic study revealed the nature of this tumor to be well compatible with that of a pineocytoma.

Aged↗
PubMed1986

[Surgical indication and limitation in hypertensive intracerebral hemorrhage of the basal ganglia].

The purpose of this paper is to elucidate surgical indication and limitation for severe hypertensive intracerebral hemorrhage in the basal ganglia (HIH) with a view toward good functional outcome. Materials were 32 patients of severe basal ganglionic hemorrhage (HIH). Neurological grading (G) for HIH, reported by Kanaya et al. in 1978, was applied. Grading on admission in 11 patients with conservative treatment was G-4a in 2, G-4b in 3 and, G-5 in 6. Preoperative grading in 21 patients with surgical treatment was G-4a in 9, G-4b in 8 and G-5 in 4. G-4a revealed semicoma without herniation signs, G-4b semicoma with herniation signs and G-5 deep coma. The interval from the onset of HIH to hematoma evacuation was from 3 to 10 hours in 14 patients, from 17 to 23 hours in 5, 44 hours in one and 5 days in one. Functional outcomes at hospital discharge were classified as follows: self-managing (SM); partially dependent (PD); fully dependent (FD); vegetative (V); dead (D). Factors which would have influenced functional outcomes were studied and the results follow. All 11 patients with conservative treatment died. On the contrary, in 21 patients with surgical treatment, the outcomes were SM in 2 patients, PD in 3, FD in 11, V in one and D in 4. Death in the 4 patients was caused by fatal complications from 8 to 24 days after the operation. In 17 surviving patients with surgical treatment, (a) Mean age of the SM or PD patients was 45 years, and that of FD or V patients was 55 years.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

[Problems in general rules/TNM classification, and prognosis--rectal cancer].

Problems in General Rules (Japan) and TNM Classification (UICC) for, and the prognoses of rectal cancer were considered. The problems of rules are concerned with the division of the rectal locations, depth of the wall invasion, lymph-node classification, vasal infiltration, edge of the resected specimen (EW), etc. And the General Rules and TNM Classification were compared in these respects stage by stage. The locations of rectal cancer (Rb, Ra, Rs,) are asked to be indicated, setting up the borders at 1 cm, 6 cm, 12 cm above DL (dentate line), as Rb (1.1-6.0 above DL), Ra (6.1-12 above DL) and Rs (12.1-15 above DL). With regard to the depth of the wall invasion, the parts lacking in and having the serosa are asked to be contrasted as a1 and ss or a2 and s(+). With regard to ly, v that influences greatly the prognosis, it should be shown either positive or negative, and also the distance from EW be measured. Under TNM Classifications, there are observed some strains in the ratings of the metastasis of lymph-nodes and the depth of invasions, whereas the General Rules are quite peculiar of them. And it is of great rate clinical significance that the stages have been provided depending on the difference of ratings.

Humans↗
PubMed1985

Inhibition by islet-activating protein of a chemotactic peptide-induced early breakdown of inositol phospholipids and Ca2+ mobilization in guinea pig neutrophils.

Receptors for a chemotactic peptide (fMet-Leu-Phe) in guinea pig neutrophils were primarily coupled to phospholipase C catalyzing breakdown of phosphatidylinositol 4,5-bisphosphate to inositol 1,4,5-trisphosphate, which was in turn responsible for intracellular Ca2+ mobilization. These early responses of neutrophils to fMet-Leu-Phe, eventually leading to O2- generation, were abolished by prior exposure of cells to islet-activating protein (IAP), pertussis toxin, which had been reported to bring about ADP-ribosylation of a membrane Mr = 41,000 protein (Okajima, F., and Ui, M. (1984) J. Biol. Chem. 259, 13863-13871). The IAP substrate, probably the inhibitory guanine nucleotide-binding regulatory component of adenylate cyclase (Ni) or an analogous protein, is hence proposed to mediate fMet-Leu-Phe receptor-linked activation of the phospholipase C. In support of this proposal, A23187 and phorbol myristate acetate which stimulate arachidonate release or O2- generation by-passing these early processes of signaling were effective in IAP-treated cells as well. Release of arachidonic acid and accumulation of inositol 1-monophosphate in delayed response to fMet-Leu-Phe were also abolished by the IAP treatment of cells, despite the fact that slowly-onset inflow of Ca2+ which must be responsible for these delayed responses was observed in these IAP-treated cells. Thus, the IAP substrate may play an additional role in Ca2+-dependent activation of somehow compartmentalized phospholipases.

Adenylate Cyclase Toxin↗
PubMed1985

delta 9-Tetrahydrocannabinol elicited ipsilateral circling behavior in rats with unilateral nigral lesion.

The present study was designed to examine the influence of delta 9-tetrahydrocannabinol (THC) on the central dopaminergic system using circling behavior. THC 5 mg/kg i.p. produced ipsilateral circling in rats with unilateral nigral lesion by 6-hydroxy-dopamine. THC-induced ipsilateral circling was completely antagonized by 0.2 mg/kg of haloperidol. These findings suggest that THC may cause a presynaptic stimulation of nigrostriatal dopaminergic neurons.

Animals↗
PubMed1985

Taurine's possible protective role in age-dependent response to calcium paradox.

When hearts were reperfused with Ca++ after a short period of Ca++-free perfusion, irreversible loss of electrical and mechanical activity was observed. This phenomenon, first described by Zimmerman and Hulsmann, was termed the "calcium paradox". Chizzonite and Zak recently reported that rat hearts exhibited an age-dependent response in a calcium paradox model. The taurine (2-aminoethanesulfonic acid) content of hearts in the newborn animal is high, and decreases rapidly during the first few days of life. The present experiments were performed to test whether the myocardial taurine content was closely linked to an age-dependent response in the calcium paradox model, using post-hatched chicks. The mechanical dysfunction of the heart was much more severe in 9-day-old post-hatched chicks than in 2-day-old chicks when the hearts were subjected to the calcium paradox. Myocardial taurine content was lower in the 9-day-old chicks than in the 2-day-old chicks. The age-related response to the calcium paradox was partially protected by oral pretreatment with taurine, and there was a small increase in myocardial taurine level. It is proposed that myocardial taurine is one factor in the protection against the calcium paradox phenomenon.

Administration, Oral↗
PubMed1985

Central effects of DN1417, a novel TRH analog, on plasma glucose and catecholamines in conscious rats.

Intracerebroventricular (icv) injection of DN1417 (0.3, 3 and 30 nmol/rat), a TRH analog, resulted in a dose-related increase in plasma glucose, epinephrine and norepinephrine levels in conscious male rats. The effects of DN1417 were more potent and longer-lasting than those of TRH on a molar basis. Intravenous injection of DN1417 (30 nmol/rat) did not change plasma glucose, epinephrine and norepinephrine levels. Pretreatment with hexamethonium (1.5 mg/100 g body wt, iv, 2 min before) inhibited plasma glucose, epinephrine and norepinephrine responses to DN1417 (3 nmol/rat, icv). DN1417 did not change plasma glucose, epinephrine and norepinephrine levels in rats after total adrenalectomy. In the animals pretreated with cysteamine (30 mg/100 g body wt, sc, 4 h before), basal plasma glucose, epinephrine and norepinephrine levels were raised, and exaggerated responses of plasma glucose, epinephrine and norepinephrine to DN1417 (3 nmol/rat, icv) were obtained. These results indicate that DN1417 has a potent and long-lasting effect in the central nervous system in stimulating the secretion of catecholamines through the autonomic nervous system, which is associated with an elevation of plasma glucose and that endogenous hypothalamic somatostatin may inhibit the action of DN1417.

Adrenalectomy↗
PubMed1985

Inhibition by antiserum to vasoactive intestinal polypeptide (VIP) of prolactin secretion induced by serotonin in the rat.

Intraventricular (i.c.v.) injection of serotonin (5HT) or intravenous (i.v.) injection of 5-hydroxytryptophan (5HTP), a precursor of 5HT, raised plasma prolactin (PRL) levels in urethane-anesthetized rats pretreated with normal rabbit serum. When the animals were injected i.c.v. or i.v. with specific anti-VIP rabbit serum, the plasma PRL responses to 5HT and 5HTP were blunted. These findings suggest that hypothalamic VIP is involved, at least in part, in PRL secretion induced by central serotonergic stimulation in the rat.

5-Hydroxytryptophan↗
PubMed1985

Therapeutic effect of taurine in congestive heart failure: a double-blind crossover trial.

In a double-blind, randomized, crossover, placebo-controlled study, we investigated the effects of adding taurine to the conventional treatment in 14 patients with congestive heart failure for a 4-week period. Compared with placebo, taurine significantly improved the New York Heart Association functional class (p less than 0.02), pulmonary crackles (p less than 0.02), and chest film abnormalities (p less than 0.01). A benefit of taurine over placebo was demonstrated when an overall treatment response for each patient was evaluated on the basis of clinical examination (p less than 0.05). No patient worsened during taurine administration, but four patients did during placebo. Pre-ejection period (corrected for heart rate) decreased from 148 +/- 14 ms before taurine treatment to 137 +/- 12 ms after taurine (p less than 0.001), and the quotient pre-ejection period/left ventricular ejection time decreased from 47 +/- 9 to 42 +/- 8% (p less than 0.001). Side effects did not occur in the patients during taurine. The results indicate that addition of taurine to conventional therapy is safe and effective for the treatment of patients with congestive heart failure.

Administration, Oral↗