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Biomedical subjects

M Nakagawara

Publications and source records attributed to M Nakagawara.

At least 19 recordsLinked to original sources
PubMed2000

A portable instrument for non-invasive monitoring of beat-by-beat cardiovascular haemodynamic parameters based on the volume-compensation and electrical-admittance method.

A new, portable instrument has been developed for simultaneous monitoring of blood pressure, cardiac output and other cardiovascular haemodynamic variables. The measurements are based on the volume-compensation method and the transthoracic electrical admittance method. The instrument is small and light and can be carried by the subject. The portable unit controls the measurement procedures, performs the blood pressure and cardiac output measurement, processes signals and stores almost 32,000 beats of time-series data in a fully automated manner. A conventional personal computer is used to initialize the measurement system, and to reproduce and evaluate the measurement data. The measurement system provides a means to evaluate in detail, without restriction, the subject's cardiovascular haemodynamic responses to daily physical activities as well as to various psycho-physiological stresses. The paper describes a new, portable, cardiovascular haemodynamic instrument and in-the-field test results. Twelve subjects are monitored for trials, 60-210 min, and fewer than 3% of the data in each trial are artifactual. Artefacts are due mainly to body movements.

Adult↗
PubMed2000

Successful treatment of percutaneous transhepatic papillary dilation in patients with obstructive jaundice due to common bile duct stones after Billroth II gastrectomy: report of two emergent cases.

Successful treatment of two patients with obstructive jaundice due to choledocholithiasis after Billroth II gastrectomy was performed by elimination of stones by percutaneous transhepatic balloon dilatation of the sphincter of Oddi. Patient 1 was an 82-year-old man and Patient 2 was a 73-year-old man. Both patients presented with obstructive jaundice. The papilla was not observed in either patient because of previous Billroth II gastrectomy. Because an endoscopic approach was impossible, percutaneous transhepatic cholangiodrainage (PTCD) was performed to alleviate jaundice. Choledocholithiasis was treated as follows: The sphincter of Oddi was dilated by percutaneous transhepatic balloon, and stone particles were removed from the papilla with a stone-eliminating balloon catheter via the same route of PTCD. This method is less invasive than the percutaneous transhepatic cholangioscopic method, and the use of existing appliances such as a balloon for papillary dilation is possible. Hence, this method appears to be an effective and simple method for the treatment of choledocholithiasis after gastrectomy that is difficult to treat endoscopically.

Aged↗
PubMed1999

Preservative treatment for biliobiliary fistula.

Biliobiliary fistula is thought to be a rare type of internal biliary fistula. A 68-year-old man presented to our hospital with complaints of jaundice and general malaise. Endoscopic retrograde cholangiography was performed, but the gallbladder was not imaged. Mirizzi's sign was observed in the common hepatic duct. During the course of evaluating this inpatient, imaging revealed that a gallstone was extruded to the right hepatic duct. After incision of the papilla, stones in the bile duct were subjected to mechanical lithotripsy and were extracted. As a result of bile duct decompression, the biliobiliary fistula was closed completely 2 months later.

Aged↗
PubMed1997

Strain difference in behavioral response to a new environment in rats.

Locomotor activity in rats throughout a 24-hour period in a new environment was examined for strain differences and for the capacity for adaptation to that environment. Fischer 344 rats (F344), spontaneously hypertensive rats (SHR) and Wistar normotensive Kyoto rats (WKY) were used. The horizontal locomotor activity of individual rats was measured by photocell-utilizing activity-recording devices. The locomotor activity counts on the second day, after 1 day of adaptation, were compared with those after 5 days of adaptation (on the sixth day). In WKY, there was no difference in activity at any period of the day between the second and sixth days. In SHR, the locomotor activity on the second day between 6:00 h and 9:00 h (in the light phase) and between 24:00 h and 3:00 h (in the dark phase) was higher than on the sixth day. In F344, the locomotor activity on the second day between 18:00 h and 2:00 h was higher than on the sixth day. The capacity for adaptation in SHR and F344 was thus poorer than in WKY. The poor adaptation in SHR and F344 was similar to that in depressive patients induced by moving house. These findings suggested that SHR or F344 were suitable for depression research.

Animals↗
PubMed1996

Effect of a phenylethanolamine N-methyltransferase inhibitor, 2,3-dichloro-alpha-methylbenzylamine, on the alpha-2-adrenoceptor function in the hypothalamus in rats.

This study examines the in vivo effects of 2,3-dichloro-alpha-methylbenzylamine (DCMB), a centrally active phenylethanolamine-N-methyltransferase (PNMT) inhibitor, on alpha 2-adrenoceptors. Sixty-six rats received either DCMB, SKF29661, the peripheral PNMT inhibitor, at a dose of 50 mg/kg or saline intraperitoneally. To examine the functional responses of the alpha 2-adrenoceptors to these drugs, changes in spontaneous locomotor activity, concentration of 3-methoxy-4-hydroxyphenylglycol (MHPG) in dialysates from the hypothalamus, and the influence of clonidine on growth hormone (GH) secretion were investigated. (1) DCMB increased spontaneous motion of the rat. (2) DCMB increased extracellular MHPG concentration in the hypothalamus verified by micro-brain dialysis. (3) Clonidine failed to stimulate GH secretion in DCMB-treated rats. These results suggest that DCMB has an inhibitory action on the alpha 2-adrenoceptor function in vivo.

Animals↗
PubMed1996

Effect of phenylethanolamine N-methyltransferase inhibitor, CGS19281A, on the alpha-2-adrenoceptor function in the hypothalamus of rats in comparison with SKF29661, SKF64139 and yohimbine.

CGS19281A, a phenylethanolamine N-methyltransferase (PNMT) inhibitor, is reported not to inhibit alpha-2-adrenoceptor activity, in vitro. Effects of CGS19281A on the hypothalamic alpha-2-adrenoceptor function were studied in vivo in male Wistar rats. Agents used as controls were SKF29661, which is a selective peripheral PNMT inhibitor, SKF64139, a PNMT inhibitor that inhibits equally both alpha-2-adrenoceptor activity and PNMT, and yohimbine, an alpha-2-adrenoceptor inhibitor that does not inhibit PNMT. Following the administration of PNMT inhibitors, hypothalamic 3-methoxy 4-hydroxy phenylglycol (MHPG) was measured during micro brain dialysis to observe its fluctuations. Effects of PNMT inhibitors on growth hormone (GH) secretion caused by clonidine were examined in order to assess the effects of PNMT inhibitors on postsynaptic alpha-2-adrenoceptors in the hypothalamus. Neither saline nor the peripherally active PNMT inhibitor SKF29661 (50 mg/kg) increased hypothalamic MHPG. Both SKF64139 (50 mg/kg) and yohimbine (5 mg/kg) increased MHPG significantly when compared with SKF29661. There was no significant increase in MHPG after the administration of CGS19281A (20 mg/kg). Blood GH increased 30 min after clonidine was administered. While CGS19281A (20 mg/kg), SKF64139 (50 mg/kg) and yohimbine (5 mg/kg) inhibited GH secretion, the peripherally active PNMT inhibitor SKF29661 (50 mg/kg) did not. These results suggest that CGS19281A has an in vivo inhibitory effect on the clonidine induced GH secretion. This may be due to inhibition of adrenaline synthesis by this agent.

Animals↗
PubMed1995

Factors affecting quality of ulcer healing after lansoprazole treatment.

To evaluate endogenous and exogenous factors affecting the quality of ulcer healing produced by proton pump inhibitors, gastric acid pH, serum gastrin, and serum pepsinogen (PG) I and II were measured in peptic ulcer patients before and after treatment with lansoprazole 30 mg once daily. Lansoprazole achieved more rapid scarring in duodenal ulcer (n = 34), with a healing rate of 97.1% after 6 weeks, than in gastric ulcer (n = 56), with a healing rate of 92.8% after 8 weeks. Scarring was the most rapid in gastroduodenal ulcer (n = 8), with a healing rate of 100% after 8 weeks, but the rate of complete scarring was the lowest (37.5%). Lower gastric acidity and lower PG I:II ratio were associated with poor quality ulcer scarring in patients with gastric ulcers, but the opposite was true for those with duodenal and gastroduodenal ulcers. For gastric ulcers, not only ulcer size but also mucosal atrophy was an important factor in ulcer healing. Smoking and alcohol consumption had little effect on the quality of ulcer healing during treatment. These results suggest that there are a number of differences between gastric ulcers and duodenal ulcers in terms of the quality of ulcer healing after lansoprazole treatment.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed1994

[Neuropeptide Y: psychopharmacological and clinical aspects].

Neuropeptide Y is a 36-amino acid peptide that is widely distributed in the brain. Recently, three neuropeptide Y receptor subtypes were discovered with the aid of peptidergic agonist analogs of neuropeptide Y. Many researchers reported that neuropeptide Y might be involved in locomotor activity, eating behavior, stress responses, memory processing, circadian rhythms, blood pressure and neuroendocrine functions. It was also reported to interact with sigma receptor and corticotropin-releasing factor. Clinical evidence suggests that neuropeptide Y might be related to depression, schizophrenia, anorexia nervosa and Alzheimer's disease. In this review, central distribution and receptor subtypes of neuropeptide Y, its physiological action and its levels in cerebrospinal fluid and plasma in psychiatric and neurological illnesses are described.

Alzheimer Disease↗
PubMed1992

Beta-phenylethylamine and noradrenergic function in depression.

1. The relationship between plasma levels of beta-phenylethylamine (PEA) and 3-methoxy-4-hydroxyphenylglycol (MHPG) was investigated in depressive patients. 2. The mean PEA level in plasma in healthy subjects was 1.19 ng/ml (N = 32). No clearly age-related difference was found. The plasma levels of PEA were measured in major depression, but no significant difference was found between healthy and depressive subjects. 3. Plasma levels of MHPG correlated positively with age in healthy subjects (N = 22, R = 0.71, p less than 0.01). There was no significant difference in MHPG levels between healthy subjects and depressive patients. 4. There was no significant correlation between PEA and MHPG levels in healthy subjects; however, in depressive patients, there was a significant negative correlation between plasma PEA levels and plasma MHPG levels (N = 14, R = -0.73, p less than 0.05). These results suggested that PEA may regulate noradrenergic function in depression.

Depressive Disorder↗
PubMed1989

Anterior-posterior relationships of EEG in photosensitive subjects: coherence and cross-phase-spectral analysis.

Coherence and cross-phase-spectral analysis of EEG were applied to photo-sensitive subjects to investigate the mechanism of the generalization of photo-induced paroxysms. Coherence values were high between frontal (F) and central (C) in resting records and between F-C in EEGs revealing harmonic responses, where the coherence values of F-O (occipital) were also high, and the waves of F preceded those of O. In cases of occipital-localized 3/6 Hz (poly) spike-waves, discharges of O preceded those of F. During the stage of generalized paroxysms, discharges were highly cohered between all electrodes. Discharges of F preceded those of O, and appeared to play as a generator. Two conditions with clinical symptoms had higher frequencies (greater than or equal to 12 Hz) and shorter time lags (less than or equal to 5 msec) than conditions without symptoms.

Adolescent↗