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Biomedical subjects

S Koyanagi

Publications and source records attributed to S Koyanagi.

At least 37 records · Page 2Linked to original sources
PubMed1998

HSP90 has neurite-promoting activity in vitro for telencephalic and spinal neurons of chick embryos.

We purified a protein from the extract of denervated chick muscle. The protein had neurite-promoting activity in vitro for the chick telencephalic neurons and spinal neurons. Partial amino acid sequencing and immunoblotting revealed that the protein was chick heat shock protein 90 (HSP90). Commercially available bovine HSP90 and recombinant chick HSP90 expressed in Escherichia coli also showed the same activity. Since HSP10 (GroES) and HSP60 (GroEL) exhibited no activity for neurite outgrowth in the same culture, this activity was specific to HSP90 among the heat shock proteins.

Amino Acid Sequence↗
PubMed1998

Neurite outgrowth-promoting factors in extracts of denervated chick skeletal muscle.

1. An extract of denervated skeletal muscle contained activity for promotion of neurite outgrowth from telencephalic neurons, as well as that from neurons in the spinal cord. A factor responsible for the activity was characterized in cultures of dissociated neurons. 2. The factor acted on neurons only when they were attached to the surface of culture dishes. Since treatments with proteases and lectins reduced the outgrowth-promoting activity, the factor was thought to be a glycoprotein. 3. Among the monoclonal antibodies raised against the partially purified extract, five antibodies were found to inhibit the activity for spinal and telencephalic neurons. The most potent antibody, 4D2a, recognized mainly a 63-kD protein and other minor proteins in the extract. Although the 63-kD protein was confirmed to be chick serum albumin by analysis of amino acid sequence, the purified albumin exhibited no activity. 4. From these observations, the factor was found to be a glycoprotein recognized by the neutralizing antibody as one of the minor components of the extract. This factor exhibits its activity in a substrate-bound form but not in a diffusible one.

Amino Acid Sequence↗
PubMed1998

Evaluation of the early stage of carotid atherosclerosis using the vascular response to nitroglycerin and high-resolution ultrasonography.

The purpose of this study was to determine whether the early stages of arterial atherosclerosis could be evaluated by the vascular response to nitroglycerin (NTG). The vascular elasticity of the common carotid artery (CCA) was evaluated at sites without atheromatous plaque using high-resolution ultrasonography before and after sublingular NTG administration. The vascular elasticity was expressed by vascular strain (VS) and pressure-strain elastic modulus (Ep). The study was performed in 9 normal young males (group N) and 52 patients who were suspected to have coronary artery disease (CAD). In group N, VS of the CCA increased from 9+/-2 to 13+/-4%, Ep decreased from 80+/-18 to 42+/-14 kPa (p<0.01) and systolic blood pressure (SBP) decreased from 116+/-8 to 109+/-8 mmHg (p<0.05) after NTG administration. Two different responses were observed in the patients. One group of patients (group A, n=27) showed similar responses to NTG as those of group N; that is, VS increased from 8+/-4 to 14+/-8%, Ep decreased from 115+/-64 to 57+/-31 kPa (p<0.01) and SBP decreased from 121+/-15 to 110+/-16 mmHg (p<0.05). In the other group (group B, n=25), in spite of SBP decreasing from 124+/-21 to 111+/-21 mmHg (p<0.05), VS decreased from 11+/-4 to 7+/-3% and Ep increased from 76+/-29 to 113+/-53 kPa (p<0.01). The prevalence and severity of CAD were lower in group A than in group B (33 vs 80%, 11 vs 60%, p<0.01, respectively). The prevalence of atheromatous plaque of the CCA was also lower in group A than in group B (4 vs 22%, p<0.01). These results revealed that the prevalence of carotid atheromatous plaque was highly correlated with that of CAD (p=0.001) and suggested that the vascular elasticity response of the CCA to NTG is highly associated with atherosclerotic changes of the artery and may be a useful method for detecting the early stages of atherosclerosis.

Administration, Sublingual↗
PubMed1998

Correlation between wave components of the second derivative of plethysmogram and arterial distensibility.

The ratio of two wave components (magnitude of b/a constituting the second derivative of the plethysmogram (SDPTG) was correlated with arterial distensibility. Eighty-two subjects (33-93 years old) were classified into three groups according to the thickness of the intima-media complex of the common carotid artery measured by B-mode ultrasonography. One group was non-atherosclerotic (without pathologic thickening) (nAS) and the other two groups atherosclerotic (mild and severe thickening, or plaque formation) (AS-1 and AS-2). Distensibility (D) of the common carotid artery was calculated from arterial dimensions and blood pressure: h/p = D, where h = (Ds-Dd)/Dd; Ds, Dd and p represent the inner diameter of the carotid artery at peak systole, at end diastole and brachial pulse pressure, respectively. The plethysmogram was recorded at the cuticle of the 2nd digit of the left hand, and the SDPTG was determined with a 10 msec time constant. D showed a significant negative correlation with age in all subjects and in the three separate groups. The correlation between age and magnitude of b/a was significantly negative in all subjects. This negative correlation was not observed in the nAS group, while it was significant in both AS-1 and AS-2. The correlation between magnitude of b/a and D was significantly positive in all subjects and in each group. Significant differences were found among the three groups for magnitude of b/a and D. These results suggest that a decrease in magnitude of b/a or in D was proportional to the thickness of the intima-media complex of the carotid artery, that is, the development of atherosclerosis. These results provide direct evidence that magnitude of b/a of the SDPTG is related to the distensibility of the peripheral artery, and suggest that magnitude of b/a is a useful non-invasive index of atherosclerosis and altered arterial distensibility.

Adult↗
PubMed1998

Treatment of a Brodie bite by lower lateral expansion: a case report and fourth year follow-up.

The patient was a 4 year 4 month old boy at the first visit. The chief complaint was chewing dysfunction. The intra-oral and facial films, study casts, cephalometrics, muscle-balance monitor, temporomandibular joint radiographs were analyzed. The patient presented with a Brodie bite or unilateral posterior cross bite. The upper dental arch was wider than other children of his age. The lower dental arch was significantly smaller than the upper dental arch. The lower dental arch was expanded using a Schwarz appliance. The period of treatment was one year and two months. The period of observation was four years and ten months. First the patient underwent chewing training and secondarily then was treated by lateral expansion. After this treatment the patient achieved good occlusion and muscle function, while the morphology and function of the temporomandibular joints were improved, as well.

Cephalometry↗
PubMed1997

Circadian rhythm of fever induced by interferon-alpha in mice.

The influence of dosing time on the fever induced by interferon-alpha (IFN-alpha) was investigated in ICR male mice under light-dark cycle. There was a significant circadian rhythm in rectal temperature, as an index of fever, at 1 hr after IFN-alpha (10 MIU/kg, i.v.) injection. The rhythmic pattern resembled overall the rhythm occurring in the nondrugged state. IFN-alpha increased rectal temperature during the light phase, but not during the dark phase. The fever induced by IFN-alpha was blocked by indomethacin (10 mg/kg, i.p.) pretreatment. There was no significant difference of plasma IFN-alpha concentrations at 0.167, 0.5 and 1 hr after IFN-alpha injection. Therefore the dosing time dependent difference of fever induced by IFN-alpha may be caused via that of PGE2 level elevated by IFN-alpha. The choice of the most appropriate time of day for drug administration may help to achieve rational chronotherapeutics of IFN-alpha.

Analgesics, Non-Narcotic↗
PubMed1997

Autoimmune pancreatitis as a new clinical entity. Three cases of autoimmune pancreatitis with effective steroid therapy.

The most common forms of chronic pancreatitis are related to alcohol ingestion, whereas the entity of non-alcohol-associated (idiopathic) pancreatitis is poorly understood. Autoimmunity has been suggested as a possible etiologic factor of idiopathic chronic pancreatitis. A total of 362 Japanese patients underwent endoscopic retrograde pancreatography (ERP) for suspected pancreatic disease, and 161 were diagnosed with chronic pancreatitis. Among them, we found three cases (1.86% incidence) of unique chronic pancreatitis, in which ERP revealed diffuse narrowing of the main pancreatic duct with an irregular wall. We diagnosed these three patients as having pancreatitis associated with an autoimmune mechanism morphologically and biochemically and started them on steroid therapy. The characteristics of the these three patients were as follows: hypergammaglobulinemia, eosinophilia, ultrasonography showing hypoehoic diffuse swelling in the pancreas (sausage-like appearance), ERP showing diffuse narrowing of the main pancreatic duct with irregular like thumbprint-like marks, reversible exocrine insufficiency, and positive anti-carbonic anhydrase II antibody. After one month of the treatment with steroids, pancreatitis dramatically improved morphologically and enzymatically. Here we describe these cases of the suspected autoimmune chronic pancreatitis. We must recognize the concept and the features of autoimmune pancreatitis in order to avoid unnecessary surgery as pancreatic cancer.

Aged↗
PubMed1997

Chronopharmacological study of interferon-alpha in mice.

The influence of dosing time on the pharmacological effects (fever and antiviral activity) and the pharmacokinetics of interferon-alpha (IFN-alpha) was investigated in ICR male mice under light-dark (12:12) cycle. There was a significant circadian rhythm in rectal temperature, as an index of fever, at 0.5 hr after IFN-alpha (10.0 MIU/kg i.v.) injection. The rhythmic pattern resembled overall the rhythm that occurs in the nondrugged state. However, the percent change from basal level of rectal temperature varied according to the dosing time. The rhythmicity corresponded to the dosing time-dependent difference of PGE2 levels in thalamus after IFN-alpha injection, but it did not correspond to that of plasma IFN-alpha concentrations. A significant dosing time-dependent difference was also demonstrated for 2'-5'oligoadenylate synthetase activities, as an index of antiviral activity, in plasma and liver at 24 hr after IFN-alpha injection. It was related to the rhythmicity in plasma IFN-alpha concentrations that was caused by the rhythmicity in clearance of IFN-alpha. The choice of the most appropriate time of day for drug administration may help to achieve rational chronotherapeutics of IFN-alpha in certain experimental and clinical situations.

2',5'-Oligoadenylate Synthetase↗
PubMed1997

A case of successfully treated giardiasis in pancreas.

We report a case of giardiasis in the pancreas in a patient with diabetes mellitus. The patient is interesting in the following: 1) Giardia lamblia was found only in the pancreas and not in the gall bladder by cytology on endoscopic retrograde cholangiopancreaticography (ERCP) and by cerulein-secretin test (CST). 2) ERCP revealed multiple small cysts scattered throughout the pancreas. 3) Decreased pancreatic exocrine function was recovered by treatment with metronidazole.

Aged↗
PubMed1996

Case report: mucin-producing cystic neoplasm of the pancreas with onset in childhood.

Mucin-producing tumours of the pancreas have been recently reported with increasing frequency and most cases have occurred in middle-aged and elderly people. In the present report, a case of a 21-year-old man with mucinous cystadenoma of the pancreas is reported. He had a long history of recurrent pancreatitis from the age of 8. When he was aged 10, the first branch of the main pancreatic duct was shown to be enlarged on endoscopic retrograde pancreaticography (ERP). A series of ERP studies and computed tomography scans performed over a period of 11 years demonstrated continuing growth of this enlargement of the pancreatic duct. Pancreaticoduodenectomy was performed and the patient has been well without further episodes of acute pancreatitis and has been free of recurrent tumour for 1 year.

Adult↗
PubMed1996

Abnormalities of cardiac sympathetic neuronal and left ventricular function in chronic mitral regurgitation: assessment by iodine-123 metaiodobenzylguanidine scintigraphy.

Myocardial uptake of iodine-123 meta-iodobenzylguanidine (123I-MIBG) was measured using scintigrams at rest in 12 patients with isolated, nonischemic mitral regurgitation (MR; regurgitant fraction 64% +/- 7%) and was related to the left ventricular (LV) function assessed by cardiac catheterization. Iodine-123 meta-iodobenzylguanidine activity in the upper mediastinum, liver, and lung was comparable between MR and control (n = 8) patients. The heart-to-mediastinum 123I-MIBG activity ratio 4 hours after injection was significantly (p < 0.01) decreased in MR (2.0 +/- 0.1, mean +/- SE) compared with control (2.7 +/- 0.1) with the increased clearance of MIBG. In addition, MR patients had significantly greater heterogeneity in the 123I-MIBG distribution within the myocardial images (26.1% +/- 2.1% intraimage variability for MR versus 15.6% +/- 0.8% for control, p < 0.01). Myocardial 123I-MIBG activity correlated positively with cardiac index and negatively with pulmonary capillary wedge pressure and LV volume indexes. Thus, 123I-MIBG scintigrams can be a noninvasive method for assessing the contractile dysfunction in MR.

3-Iodobenzylguanidine↗
PubMed1995

Protective effect of nitric oxide on development of acute pancreatitis in rats.

Nitric oxide (NO) has been implicated to regulate pancreatic circulation, promote capillary integrity, and inhibit leukocyte adhesion. We investigated the role of NO in the development of pancreatitis. Nitro-L-arginine, an inhibitor of NO synthase, in total dose of 35 mg/kg body wt was infused in the rats with edematous pancreatitis induced by two intraperitoneal injections of cerulein (20 micrograms/kg). L-Arginine (125 or 250 mg/kg), a NO donor was intravenously administered twice in the rats with hemorrhagic pancreatitis induced by water-immersion stress plus two intraperitoneal injections of cerulein (40 micrograms/kg). The degree of pancreas edema, serum amylase levels, and histologic alterations were investigated. Nitro-L-arginine exacerbated cerulein-induced pancreatitis and caused a decrease in pancreatic blood flow. L-Arginine ameliorated the severity of hemorrhagic pancreatitis dose dependently and improved the pancreatic blood flow. These findings suggest that NO could confer protection against the development of hemorrhagic pancreatitis, probably through improvement of the pancreatic microcirculation.

Acute Disease↗