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Biomedical subjects

T Kumazawa

Publications and source records attributed to T Kumazawa.

At least 307 records · Page 17Linked to original sources
PubMed1989

Concentrations of catecholamines and indoleamines in the central nervous system of Wriggle mouse Sagami.

1. The concentrations of norepinephrine (NE), 3-methoxy-4-hydroxyphenylglycol (MHPG), 5-hydroxytryptamine (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) in the central nervous system of Wriggle mouse Sagami (WMS), which is a new ataxic mutant mouse, were studied. 2. NE and MHPG levels were increased most remarkably in the cerebellum. 3. 5-HT and 5-HIAA levels were increased most remarkably in the brain stem and spinal cord. 4. The present results suggest enhancement of catecholamine and indoleamine metabolism in the cerebellum and bulbospinal cord, respectively, of the WMS, and these changes seem relevant to the specific motor dysfunction of the WMS.

Animals↗
PubMed1989

Acceptance of murine thyroid allografts by pretreatment of anti-Ia antibody or anti-dendritic cell antibody in vitro.

A new method for thyroid allografts in mice was established. Thyroids of C67BL/6J mice were treated with collagenase, and the follicles were isolated using a Percoll density gradient technique. These follicles were treated with anti-Ia antibody (Ab) or anti-DC Ab plus complement in order to eliminate DCs. The follicles were then mixed with agarose and transplanted under the left renal capsule of BALB/c mice. One hundred days after transplantation, acceptance of the grafts was verified by both histological study and the incorporation of 125I into the grafts. Allografts treated with C were rejected, whereas allografts treated with Ab plus C were accepted. When nontreated thyroids of C57BL/6J mice were grafted under the right renal capsule of BALB/c mice that had accepted DC-depleted thyroids of C57BL/6J mice, the nontreated thyroids were rejected. These findings indicate that DCs play a crucial role in the rejection of mouse thyroid allografts, and that the depletion of DCs permits allografts to be accepted without inducing donor-specific tolerance. Our method presented here may be developed as a viable strategy for the treatment of patients with congenital or acquired hypothyroidism.

Animals↗
PubMed1989

Effects of ionic calcium on the responses of canine testicular polymodal receptors to algesic substances.

1. To explore possible mechanisms of the responses to algesic substances (bradykinin, hypertonic saline, and high K+ solution) of polymodal receptors in the canine testis, the Ca2+ concentration was varied in vitro. 2. After 1 min in Ca2+-free media, the responses to both high K+ solution (60 mM K+) and hypertonic saline (0.6 M Na+) were significantly augmented and tended to increase further with time; return to normal Ca2+ concentration quickly reversed these changes. These augmenting effects were blocked by the substitution of Mg2+ for Ca2+. The excitation produced by 60 mM K+ was decreased by increasing Ca2+ in a concentration-dependent fashion. 3. Reducing the bath concentration of K+ decreased responses evoked by 9 X 10(-8) M bradykinin (BK), whereas increased K+ concentration had the opposite effect. 4. The excitatory effects of BK were significantly suppressed in extracellular Ca2+-free condition. The suppression was not affected by the addition of Mg2+. Prostaglandin E2, which has been known to be released by BK and to augment the BK response, failed to restore the suppressed response by either preapplication (2.8 X 10(-7) M) or simultaneous application in high concentration (1.4 X 10(-5) M). 5. On the basis of these observations, it was postulated that Ca2+ concentration-dependent changes of the responses to 60 mM K+ and 0.6 M Na+ results from Ca2+-dependent "membrane surface potential" changes. The suppressed response to BK by Ca2+ depletion may be explained by the intervention of Ca2+-dependent processes other than PG production.

Animals↗
PubMed1989

Gas permeability of round window membrane.

The perilymphatic oxygen tension in the scala tympani was measured with a polarographic technique after various gases were insufflated into the middle ear cavity of 7 guinea pigs. Pure oxygen, insufflated into the middle ear cavity, easily permeated the round window membrane and elevated the perilymphatic oxygen tension. Oxygen transport to the inner ear, other than by the inner ear vessels, was confirmed. The inner ear function may partially be maintained by oxygenation through this route.

Animals↗
PubMed1989

Recurrent bacterial meningitis. Secondary to malformation of the inner ear.

A 5-year-old girl with congenital sensorial deafness experienced four episodes of bacterial meningitis in a 13-month period. On the fourth episode, an extensive search for the cause of recurrent meningitis was conducted. Complete immunologic studies, humoral, cellular, and phagocytic, yielded negative results. Precise otological examination, i.e., skull roentgenograms, an inner ear target CT scan, and puncture of the eardrum, was attempted, which disclosed the inner ear malformation (Mondini's anomaly) and a cerebrospinal fluid (CSF) fistula. CSF discharge from the oval window was repaired surgically. Extensive otologic evaluation should be conducted in patients with recurrent bacterial meningitis.

Cerebrospinal Fluid Otorrhea↗
PubMed1989

Rapid isolation with Sep-Pak C18 cartridges and wide-bore capillary gas chromatography of some barbiturates.

A simple and rapid method for isolation of nine barbiturates with Sep-Pak C18 cartridges from human urine, plasma and whole blood, is presented; the detection of drugs was made by wide-bore capillary gas chromatography (GC) with flame ionization. The drug-containing samples, after mixing with dilute acid solution, were directly applied to the cartridges and eluted with either chloroform/methanol (9:1) or acetonitrile. Separation of the nine drugs was satisfactory with use of an intermediately polar HP-17 capillary column. Recoveries of most compounds were excellent for both chloroform/methanol and acetonitrile as elution solvents. However, backgrounds were cleaner and evaporation time was much shorter for the chloroform/methanol system. The present isolation method with use of Sep-Pak C18 cartridges and wide-bore capillary GC seem very useful in the fields of forensic chemistry, clinical toxicology and clinical pharmacology.

Barbiturates↗
PubMed1989

Quantitative immunocytochemical localization of Na+,K+-ATPase alpha-subunit in the lateral wall of rat cochlear duct.

Ultrastructural localization of the alpha-subunit of Na+,K+-ATPase on the lateral wall of rat cochlear duct was investigated quantitatively by the protein A-gold method, using affinity-purified antibody against the alpha-subunit of rat kidney Na+,K+-ATPase. In the stria vascularis, gold particles were sparse over the endolymphatic luminal surface of the marginal cells but were numerous over the basolateral membrane. The labeling density of the basolateral membrane was almost equal to that of the same domain of the distal tubule cells of kidney. The intermediate cells were studded with a large number of gold particles on the plasma membrane domain facing the basolateral domain of the marginal cells. On the luminal surfaces of the other epithelial cells, including those of Reissner's membrane, no significant amount of gold particles was found. Many gold particles were localized on all the plasma membranes of the spiral prominence stromal cells and on the intracellular membrane domain of the external sulcus cells.

Animals↗
PubMed1989

Functional disturbances of the sympathetic nerve in experimentally-induced nasal hypersensitivity.

Norepinephrine, alpha-1 and beta adrenergic receptors in the nasal mucosa of toluene-diisocyanate sensitized guinea-pigs were evaluated quantitatively at specific points in time during a pre-determined sensitization period. At 4, 8 and 12 weeks, the norepinephrine content was reduced. The concentration of alpha-1 adrenergic receptors significantly decreased in 8- and 12-week groups. A lower density of beta adrenergic receptors was shown in the 12-week group. Signs of a return to normalcy were observed by four weeks post-sensitization. These results led us to speculate that excess norepinephrine release, which may be promoted by allergy-inducing histamine, depleted the norepinephrine at the sympathetic nerve terminal and caused a lowering of the concentration of sympathetic receptors. Functional disturbance of the sympathetic nerve was suggested by clinical findings of nonspecific nasal hypersensitivity, congestion and nasal discharge.

Animals↗
PubMed1989

Enhanced parasympathetic nerve activities in experimentally-induced nasal hypersensitivity.

In order to verify the role of cholinergic nerves in nasal allergy and nonspecific nasal hypersensitivity we have evaluated the muscarinic acetylcholine receptors and the activity of choline acetyltransferase in nasal mucosa of TDI-sensitized guinea-pigs at specific points in time during a pre-determined sensitization period. The density of muscarinic receptors was significantly elevated in animals sensitized for 8 and/or 12 weeks as well as in the group which received 12 weeks of sensitization followed by a 4 week rest period. Choline acetyltransferase activity was also enhanced at 4-, 8- and 12 weeks. These observations provide biochemical evidence of the hyperactivity of cholinergic nerves in nasal allergy which has been suggested by clinical and pharmacological studies, and lead to the speculation that enhanced parasympathetic nerve function is implicated in causing and maintaining hypersensitivity and hypersecretion in nasal allergy.

Animals↗
PubMed1989

Histamine content and histamine H1 receptor in experimentally-induced nasal hypersensitivity.

Quantitative evaluations of histamine and histamine H1 receptor were carried out in nasal mucosa of toluene diisocyanate (TDI) sensitized guinea-pigs at specific points in time during a pre-determined sensitization period. Histamine content is significantly increased at 1 week and definitely elevated after 2 weeks of sensitization. This increase was maintained throughout the sensitization period. It decreased to normal by four weeks post-sensitization. Also the relatively low histamine content immediately after TDI challenge indicated that a certain amount of histamine was released by TDI challenge. On the other hand, the density and affinity of the histamine H1 receptor was not found to be altered during TDI sensitization. These results suggest that enhanced histamine has a role in the development of nasal allergy, whereas the relevance of quantitative-alteration of the H1 receptor to histamine hypersensitivity observed in nasal allergy has not been demonstrated.

Animals↗
PubMed1989

Histamine and acetylcholine regulation of sympathetic nerve activity in guinea-pig nasal mucosa.

The regulating effects of histamine and acetylcholine (Ach) in norepinephrine (NE) transmission in nasal mucosa were investigated by analyzing 3H-NE release from isolated guinea-pig tissues. In addition, localization of the histamine H1 receptor and the muscarinic acetylcholine receptor on the sympathetic nerve in the guinea-pig nasal mucosa were examined by quantitatively evaluating these receptors after the unilateral removal of the superior cervical ganglion. Ach inhibited electrically-stimulated 3H-NE release in a concentration-dependent manner, and this effect was blocked by atropine. Histamine inhibited electrically-induced 3H-NE release at a concentration of 10(-5) M but enhanced it in concentration of 10(-3) M. Histamine increased the spontaneous release of 3H-NE in a dose-dependent manner, which was inhibited by pyrilamine (H1 antagonist) and excess Ach, but was not altered by cimetidine (H2 antagonist). These results suggest the following: 1) Local regulation of NE transmission in nasal mucosa involved excitatory H1 receptors, inhibitory H2 receptors and inhibitory muscarine receptors which can be facilitated by sensory stimulation with histamine. 2) Histamine regulation may vary with a balance between the excitatory and inhibitory effects. 3) Histamine in the high concentrations seen in cases of nasal allergy, may shift this balance causing increased NE release; at low concentrations, NE release is inhibited. In the second series of this study, we were unable to demonstrate a decreased number of either H1 or muscarine receptors on the side affected by unilateral cervical ganglia sympathectomy.

Acetylcholine↗
PubMed1989

Norepinephrine content in guinea-pig nasal mucosa response to histamine and methacholine provocation.

The effects of histamine and methacholine (cholinergic substance) on norepinephrine (NE) content in nasal mucosa of the guinea-pig has been investigated. Histamine application for seven consecutive days was found to reduce NE content on both sides of nasal mucosa with bilateral provocation and on the affected side with unilateral stimulation, whereas NE content increased on the unaffected side with unilateral application. Methacholine provocation enhanced NE content on both sides after the bilateral application to nasal mucosa and the affected side after the unilateral application, whereas there was no effect on the other side. Time course evaluation of NE content after unilateral histamine application demonstrated that NE content on the affected side was decreased 30 min after application, but was restored to a normal level by 120 min after application; there was no change on the other side. These results suggest that histamine promotes NE release in nasal mucosa although it possesses the inhibitory effect mediated by the parasympathetic nerve, suggesting that repeated histamine stimulation may deplete NE content and cause a functional disturbance of the sympathetic nerve predisposing patients to the non-specific nasal hypersensitivity observed in nasal allergy.

Animals↗
PubMed1989

Etiology of nasal polyps associated with aspirin-sensitive asthma.

It is well known that nasal polyps occur at high frequency in aspirin-sensitive asthma (ASA). Their etiology, however, remains obscure. Therefore, histopathologic observations and measurements of arachidonic acid metabolites were carried out to investigate the etiopathogenesis of nasal polyps in ASA. Abundant eosinophils and degranulated mast cells were found in the tissue of nasal polyp-associated ASA cases. Electron-microscopic analyses of these eosinophils revealed that high-electron-dense material had disappeared from the cytoplasmic granules' central crystalloids. Arachidonic acid metabolites (PGE2, PGF2, 6-keto-PGF1 and TXB2) from the cyclooxygenase pathway were measured via gas mass-chromatography. Leukotrienes (LTC4 and LTD4) from the lipoxygenase pathway were measured via HPLC-radioimmunoassay. Especially noteworthy are the high level of leukotrienes and low level of prostaglandins in nasal polyp-associated ASA. The etiopathogenesis of nasal polyps in aspirin-sensitive asthma is postulated.

Arachidonic Acid↗
PubMed1989

[Effects of inhalation anesthetics on hepatic ATP and L/P ratio in the rat subjected to hemorrhagic shock].

Both anesthetics and hemorrhage may affect the hepatic energy metabolism. The effects of inhalation anesthetics (halothane, enflurane and isoflurane) on hepatic ATP level and L/P ratio were evaluated in rat under hemorrhagic shock. There was no significant difference in the hepatic ATP levels among 4 groups. However the L/P ratio in 3 inhalation anesthetic groups was significantly lower than that in control group. These results suggest that inhalation anesthetics may improve the hepatic energy metabolism during hemorrhagic shock.

Animals↗
PubMed1989

[A case report of hypoxia in a child after renal transplantation].

A 4 year-old boy underwent renal transplantation and the kidney was given by his mother. Anesthesia was induced slowly with halothane and nitrous oxide in oxygen. The trachea was intubated with pancuronium and the anesthesia was switched to neurolept anesthesia. Blood, plasmanate and crystalloid were infused in order to increase the circulatory blood volume measuring the CVP before the kidney was transplanted because it was so large for the child that it could not be perfused adequately. The spontaneous breathing and soon the recovery followed immediately after the end of operation. However, the patient became hypoxic on the next day probably due to the aspiration of gastric juice. He recovered from hypoxia after 3 days since the aspiration pneumonia was not severe. When the adult kidney is transplanted into a very small child, gastric juice can easily be regurgitated because of the high intraabdominal pressure. Therefore, we must be careful when a child undergoes renal transplantation.

Anesthesia, General↗
PubMed1989

[Anesthetic management in surgery of a descending aortic aneurysm in an eighteen-month-old boy].

Aortic aneurysm occurs rarely in childhood. Most aneurysms in children are associated with conditions such as Marfan's syndrome, coarctation of the aorta, Ehlers-Danlos syndrome and neurofibromatosis. We report a case of descending thoracic-abdominal aortic aneurysm in an eighteen month old boy with a mask-like face, ocular hypertelorism, blepharoptosis, a high arched palate and low set ears. He was scheduled for a bypass graft of the descending thoracic and abdominal aorta under partial cardiopulmonary bypass. High dose morphine anesthesia (2mg/kg) was employed and halothane was used to control the blood pressure. To our knowledge, anesthetic management of such an infant had not been reported. Therefore, we anesthetized this child according to anesthetic managements for adult cases considering carefully the boy's multiple anomalies. Anesthetic managements for the surgery of aortic aneurysms in childhood are discussed.

Anesthesia↗