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Biomedical subjects

N Kanoh

Publications and source records attributed to N Kanoh.

At least 19 recordsLinked to original sources
PubMed2001

Cytochemical localization of Na+/K+-ATPase activity in cochlear strial marginal cells after various catecholamine administrations.

Sodium/potassium-activated adenosine triphosphatase (Na+/K+-ATPase) activity in the kidney and brain is high, and is regulated by catecholamines. Na+/K+-ATPase activity is also high in the basolateral infoldings of the strial marginal cells, where it aids in maintaining the characteristic electrolyte composition of the endolymph. To clarify the involvement of humoral control in strial function, particularly the role of catecholamines, the K+-dependent p-nitrophenylphosphatase (K+-NPPase) activity of strial marginal cells was investigated in guinea pigs using a cerium-based cytochemical method. The effects of reserpine, serotonin (5-HT), norepinephrine (NE), epinephrine (EP), both alone and in combination, were studied. High doses of reserpine cause depletion of sympathetic substances. Strial K+-NPPase activity was decreased after reserpine or dopamine treatment, and was increased after 5-HT, NE, and EP treatment. After reserpinization, repeated treatment with 5-HT, NE, or EP led to detectable strial enzyme activity. Thus, exogenous 5-HT, NE, and EP were able to restore strial K+-NPPase activity in the reserpine-treated animals. These results suggested that biogenic amines regulate strial K+-NPPase activity. Thus, the function of the stria vascularis may be regulated by the opposing actions of these catecholamines, and 5-HT.

4-Nitrophenylphosphatase↗
PubMed2000

Study on facial motoneuronal death after proximal or distal facial nerve transection.

BACKGROUND: Among the cranial nerves, the facial nerve is most liable to be damaged. Pathologic changes in the facial motor nucleus (FMN) after nerve injury are not well recognized, and the optimal time for facial nerve reconstruction after axotomy is controversial. In this study, to clarify the pathologic change in the FMN after axotomy and to determine the best time for surgery, facial motoneuronal death was investigated after facial nerve injury. METHODS: Sixty Wistar rats were divided into proximal and distal groups. In the proximal group, the right facial nerve was transected at the porus of internal acoustic meatus. In the distal group, the nerve was cut at the stylomastoid foramen. The animals were sacrificed from day 3 to day 60 after surgery, and the brainstem was fixed with 4% paraformaldehyde. The FMN were then examined in serial sections stained with Cresyl Violet, and facial motoneurons were counted under a light microscope. RESULTS: The death rate of facial motoneurons in the animals that underwent proximal axotomy was found to be higher and cell death occurred earlier than in the distal axotomy animals at every time point. Moreover, neuron death increased with time and peaked at 15 days after surgery. CONCLUSIONS: The results indicate that the injury site was correlated with facial motoneuronal death, and suggest that reconstructive surgery should be performed as early as possible.

Animals↗
PubMed2000

Parameters for the preoperative evaluation of arteriosclerosis for free-flap transfers in head and neck surgery.

The microsurgical transfer of free tissue has become essential for reconstructive surgery in the head and neck, and arteriosclerosis is one of the risk factors for microvascular anastomosis. In order to detect severe arteriosclerosis and to determine the parameters useful for evaluating arteriosclerosis preoperatively, the grade of arteriosclerosis was investigated with respect to age, PWV (Aortic Pulse Wave Velocity), ocular fundus findings, and histopathological findings of the recipient arteries in 40 patients with malignant tumours. Severe arteriosclerosis was detected in 2/40 patients by the PWV, in the same 2/40 patients by the ocular fundus findings and in the same 2/40 patients by histopathological findings. The current observations indicate that the PWV and ocular fundus findings are useful parameters for the preoperative evaluation of the grade of arteriosclerosis.

Adult↗
PubMed1999

Tremorgenic indole alkaloids. Studies directed toward the assembly of the A, F, and I rings of penitrem D: observation of an unexpected stereochemical outcome.

[formula: see text] In this Letter we demonstrate the viability of a highly stereoselective tandem Mannich cyclization-grammine fragmentation/addition cascade, critical for assembly of the A and F rings of penitrem D. We also explored simultaneous execution of this tactic with concurrent construction of ring I. Reinvestigation of a model system provided an explanation for the unanticipated stereochemical outcome at C(28).

Alkaloids↗
PubMed1999

Effects of epinephrine on ouabain-sensitive, K(+) -dependent P-nitrophenylphosphatase activity in strial marginal cells of guinea pigs.

In strial marginal cells, Na+/K(+)-ATPase activity is abundant, and contributes to maintain the characteristic electrolyte composition of the cochlear endolymph. In the present study, to clarify the relationship between epinephrine and strial Na+/K(+)-ATPase activity, the ouabain-sensitive, K+-dependent p-nitrophenylphosphatase (K(+)-NPPase) activity of strial marginal cells was investigated with a cerium-based method in normal guinea pigs and guinea pigs treated with reserpine, epinephrine, and reserpine plus epinephrine. In our previous study, K(+)-NPPase activity had almost completely decreased 3 to 20 days after reserpine administration. In the present study, at 10 days after reserpinization and following repeated epinephrine treatment, enzyme activity was detectable. These results suggest that exogenous epinephrine was able to restore strial K(+)-NPPase activity in the reserpine-treated animals, and that epinephrine might increase strial Na+/K(+)-ATPase activity.

4-Nitrophenylphosphatase↗
PubMed1999

Constitutive expression of GlyCAM-1 core protein in the rat cochlea.

Glycosylation-dependent cell adhesion molecule-1 (GlyCAM-1) is a mucin-like glycoprotein previously identified on high endothelial venules (HEV) of lymph nodes and also in lactating mammary glands. A specifically glycosilated form of GlyCAM-1 on HEV has been shown to be a ligand for a leukocyte L-selectin, which plays an important role in leukocyte rolling along the inflamed endothelium. Here we report that GlyCAM-1 is also expressed in the cochlea. Immunohistochemistry revealed the lateral wall of the cochlea, tectorial membrane, modiolus, organ of corti, and spiral modiolar vein (SMV) to be strongly stained with polyclonal anti-GlyCAM-1 antibody. Moreover, RT-PCR of the cochlear tissue by the use of specific oligonucleotide primers for rat GlyCAM-1 generated a 378 bp product which was then verified by nucleotide sequencing to represent GlyCAM-1. Electron microscopic investigation revealed the presence of GlyCAM-1 over the entire lumenal surface of the vessels, and the basolateral infoldings in stria vascularis. However, soluble L-selectin or mAb MECA-79 which recognizes a carbohydrate epitope on functional L-selectin ligands bound only to the spiral ligament, tectorial membrane and modiolus. These observations suggest that GlyCAM-1 expressed in the cochlear region is heterogenous in terms of its glycosylation.

Animals↗
PubMed1998

Effects of dopamine hydrochloride (Inovan(R)) on ouabain-sensitive, K+-dependent, p-nitrophenylphosphatase activity of choroid plexus in guinea pigs.

Dopamine hydrochloride (Inovan(R)) is used for the treatment of acute circulatory insufficiency. In the present study, the Na-K ATPase activity of the choroid plexus was determined normal and after repeated injections of dopamine hydrochloride using cerium-based cytochemistry. In the normal guinea pigs, the reaction product was detected on the microvilli of the choroidal epithelium, but was almost undetectable after seven repeated injections of dopamine hydrochloride. These findings suggested that high doses of dopamine hydrochloride decreased the choroidal Na-K ATPase activity.

4-Nitrophenylphosphatase↗
PubMed1998

Effect of serotonin on ouabain-sensitive, K+-dependent, p-nitrophenylphosphatase activity in strial marginal cells of normal and reserpinized guinea pigs.

Na+,K+-ATPase activity is abundant on the basolateral infoldings of the strial marginal cells and contributes to the maintenance of the characteristic electrolyte composition of the endolymph. However, the stria vascularis of the cochlea is known not to be innervated. In order to clarify its humoral regulation by serotonin, the K+-p-nitrophenylphosphatase activity of strial marginal cells was investigated with a cerium-based method in normal guinea pigs and in guinea pigs treated with reserpine, 5-hydroxytryptamine or reserpine plus 5-hydroxytryptamine. K+-p-nitrophenylphosphatase activity was almost completely depressed 3-20 days after reserpine administration. Ten days after reserpinization, followed by repeated 5-hydroxytryptamine treatment, the enzyme activity was detectable. These results suggest that 5-hydroxytryptamine increases the phosphatase activity. Thus, the function of the stria vascularis in producing cochlear endolymph may be regulated by 5-hydroxytryptamine.

4-Nitrophenylphosphatase↗
PubMed1998

Effect of norepinephrine on ouabain-sensitive, K+-dependent p-nitrophenylphosphatase activity in strial marginal cells of the cochlea in normal and reserpinized guinea pigs.

On the basolateral infoldings of the strial marginal cells in the cochlea, Na K ATPase activity is abundant. To clarify the humoral control by norepinephrine, K-NPPase activity of strial marginal cells in the cochlea was investigated in normal, reserpine, norepinephrine (NE), reserpine plus NE-treated guinea pigs using a cerium-based method. K-NPPase activity was almost completely decreased 3-20 days after reserpine administration. At 10 days after reserpinization and following NE repeated treatment, enzyme activity was detectable. These results suggested that norepinephrine might restore and regulate strial K-NPPase activity.

4-Nitrophenylphosphatase↗
PubMed1998

Cytochemical localization of ouabain-sensitive, K+-dependent p-nitrophenylphosphatase activity in the choroid plexus of normal and reserpinized guinea pigs.

High doses of reserpine induce depletion of biogenic amines. The K-NPPase activity of choroid plexus was determined after one-shot reserpine administration using cerium-based cytochemistry. In normal untreated animals, reaction product was found on the microvilli of the choroidal epithelium but was almost undetectable 3 and 7 days after reserpinization. At 20 days after reserpinization, however, it was detectable. These findings suggested that reserpine decreased the choroidal Na,K-ATPase activity, and that catecholamines might be essential to maintain normal choroidal Na,K-ATPase activity. (J Histochem Cytochem 46: 975-976, 1998)

4-Nitrophenylphosphatase↗
PubMed1997

Cytochemical localization of ouabain-sensitive, K(+)-dependent p-nitrophenylphosphatase activity in the facial nerve of reserpinized guinea pigs.

Ion-transporting Na,K-ATPase plays an essential role in nerve conduction. To clarify the cytochemical effects of reserpine on transport Na,K-ATPase activity, the localization of ouabain-sensitive, K(+)-dependent p-nitrophenylphosphatase (K-NPPase) activity was investigated in the facial nerves of normal and reserpinized guinea pigs using a cerium-based method. In the normal facial nerve, the reaction product of K-NPPase activity was observed on the internodal axolemma and Schmidt-Lanterman incisures. In the Ranvier nodes, enzyme activity was localized to the paranodal and nodal axolemma. In the reserpinized nerves, reaction product was detectable on the nodal axolemma but was undetectable on the other parts of the axolemma. Nodal K-NPPase was not affected by reserpine treatment. Therefore, the transport Na,K-ATPase on the nodal axolemma might differ from that on the other parts of the axolemma. Allowing reserpinized animals to survive. Two different ouabain-sensitive K-NPPase reactivities, "reserpine-sensitive" and "reserpine-resistant," might be present in the facial nerve of guinea pigs.

4-Nitrophenylphosphatase↗
PubMed1996

Impaired Ranvier node sodium-potassium adenosine triphosphatase may induce facial palsy.

To clarify the part of the neuron essential for myelinated nerve conduction, the cytochemical localization of potassium ion (K+)-dependent p-nitrophenylphosphatase (K-NPPase) activity was investigated in the normal and reserpine-treated facial nerve of guinea pigs. In the normal animals, K-NPPase activity was localized to the internodal axolemma and Schmidt-Lanterman incisures. In the Ranvier nodes, enzyme activity was observed along the paranodal and nodal axolemma. In reserpinized nerves, K-NPPase activity was absent along the internodal axolemma and Schmidt-Lanterman incisures. In the Ranvier nodes, however, enzyme activity was detectable only in the nodal axolemma. The reserpinized animals demonstrated no evidence of facial palsy. Because K-NPPase is essential for nerve conduction, these results indicate that the location of enzyme activity in reserpinized animals, namely the nodal axolemma, may be of prime importance in saltatory nerve conduction.

Animals↗
PubMed1996

Cytochemical effects of in vitro dopamine treatment on the Na-KATPase activity in strial marginal cells.

Dopamine is often used clinically for the treatment of patients with shock. In a previous study, the Na-KATPase (K-NPPase) activity of strial marginal cells was inhibited after the repeated in vivo administration of dopamine hydrochloride. In the present study, the K-NPPase activity of strial marginal cells was determined using a cerium-based cytochemistry after an in vitro incubation with dopamine. The enzyme reaction product was found in untreated normal strial marginal cells, but it was almost completely undetectable after an in vitro treatment with 10 mM dopamine. This finding suggested that dopamine directly inhibited the Na-KATPase activity of strial marginal cells, and that these cells might have a dopamine receptor.

Adrenergic Agents↗
PubMed1995

The role of L-threo DOPS in the control of Na-K ATPase activity of the marginal cells in the stria vascularis of reserpinized guinea pigs.

It is believed that the function of the stria vascularis in the cochlea is to produce endolymph. The mechanisms that maintain or control the function of the stria vascularis, however, remain unclear. In a previous study, we investigated the ultracytochemical effects of one-shot reserpine administration on the Na-K ATPase activity of the stria vascularis in guinea pigs. Na-K ATPase activity was shown to be completely inhibited 3-20 days after reserpinization, whereas in the present study at 20 days after reserpinization and following L-threo DOPS treatment, Na-K ATPase activity was detectable. As reserpine is an adrenergic neuron blocker, and L-threo DOPS is the precursor of noradrenaline, it seems that noradrenaline converted from L-threo DOPS was able to restore the Na-K ATPase activity in the reserpinized animals. These results suggest that catecholamines may play an essential role in the maintenance or control of the Na-K ATPase activity, and that the stria vascularis may be one of the target organs of catecholamines.

4-Nitrophenylphosphatase↗
PubMed1995

Dopamine inhibits the Na-K ATPase activity of the stria vascularis in the cochlea. In vivo ultracytochemical study.

It is believed that the function of the stria vascularis in the cochlea is to produce endolymph. However, the mechanisms that maintain and control the function of the stria vascularis remain unclear. In the present study, to clarify the role of humoral substances in the stria vascularis, a cerium-based method was used to investigate the ultracytochemical effects of intraperitoneal dopamine administration on ouabain-sensitive, K(+)-dependent, p-nitrophenylphosphatase (K-NPPase) activity, which is the second step in the formation of the Na-K ATPase complex, in the stria vascularis of guinea pigs. Na-K ATPase activity was shown to be completely inhibited after dopamine administration. This observation suggests that dopamine inhibits Na-K ATPase activity in the marginal cells of the stria vascularis, and that the stria vascularis may have dopamine receptors. Catecholamines may play an important role in the maintenance and/or control of stria vascularis function.

Adenosine Triphosphatases↗
PubMed1994

Developmental anomaly of the process of Folius.

We present four cases of an ossicular anomaly considered to consist of an abnormality of the anterior process and manubrium mallei (malleus handle). In one case, a thick bony bar was found extending from the neck of the malleus which fused with the posterior bony wall or the tympanic bone. No trace of the short process and umbo of the malleus was recognized. In two other cases, a similar bony bar was seen as well as a cartilaginous malleus handle that apparently was attached to the anterior part of the bony bar. On the basis of these findings, the bony bar was assumed to represent abnormally developed mesenchyme bone (os goniale), which later develops into the anterior process of the malleus. In the last case, no bony bar was seen, but a V-shaped ossicle was recognized, one end of which was connected to the malleus head by fibrous tissue. Since this abnormally shaped ossicle was bony and hard and no trace of the short process and umbo characteristic of the handle of the malleus was found, it was though to be an abnormally developed os goniale.

Adult↗
PubMed1994

Ultracytochemical demonstration of ouabain-sensitive, K(+)-dependent, p-nitrophenylphosphatase (Na-K ATPase) activity in cat facial nerve.

Ouabain-sensitive, K(+)-dependent, p-nitrophenylphosphatase (K-NPPase) is the second dephosphorylative property of the Na-K ATPase complex. Localization of its activity in the horizontal portion of the facial nerve in 11 normal cats was studied ultracytochemically using a cerium-based method. The fine granular reaction product of the K-NPPase activity was observed on the cytoplasmic side of the axolemma of the axon cylinder. Enzyme activity was also detected on the cytoplasmic side of the plasma membrane of Schmidt-Lanterman incisures and nodes of Ranvier. No reaction product was detected on the periaxonal and outermost plasma membrane of Schwann cells and in the myelin sheath. In control tissue samples, enzyme activity was almost completely inhibited by 10 mM ouabain, and no reaction was noted in medium without K+. The present findings indicate that localization of Na-K ATPase in the cat facial nerve simulates that of other peripheral and cranial nerves.

4-Nitrophenylphosphatase↗