Biomedical subjects

K Hoshi

Publications and source records attributed to K Hoshi.

At least 127 records · Page 7Linked to original sources

PubMed1997

Fibroblasts of spinal ligaments pathologically differentiate into chondrocytes induced by recombinant human bone morphogenetic protein-2: morphological examinations for ossification of spinal ligaments.

To elucidate the process of ossification in spinal ligaments, an aqueous solution containing recombinant human bone morphogenetic protein (BMP)-2 (40 micrograms/100 microL) was injected into murine ligamenta flava, and the ossification process was analyzed morphologically. In the control group, the solution administered lacked the protein; these flattened ligamentous fibroblasts possessing BMP receptors type IA and type II existed among type I collagen bundles. In the week immediately following the injection of BMP-2, ligamentous fibroblasts began to proliferate, differentiating into alkaline phosphatase-positive chondrocytes surrounded by an extracellular matrix composed of type I and II collagen. By the second week, differentiated chondrocytes of various stages were observed in type II collagen-rich matrix. These chondrocytes showed an abundance of BMP receptors type IA and II. The pathologically induced cartilage was resorbed by chondroclasts, permitting migration of blood vessels and osteogenic cells, as well as providing a site for endochondral ossification. By the third week, BMP-induced ossification had compressed the spinal cord, and by the sixth week, the ligamentous tissue had been almost completely replaced by bone. Ligamentous fibroblasts appeared to possess BMP receptors, as well as the potentiality to differentiate into chondrocytes. BMP receptors were upregulated during chondrification of ligamentous fibroblasts induced by exogenous BMP-2, suggesting that BMPs may play an important role in ossification of spinal ligaments.

Acid Phosphatase↗

PubMed1997

Role of NMDA receptors in pentobarbital tolerance/dependence.

Effects of continuous pentobarbital administration on binding characteristics of [3H]MK-801 in the rat brain were examined by autoradiography. Animals were rendered tolerant to pentobarbital using i.c.v. infusion of pentobarbital (300 micrograms/10 microliters/hr for 7 days) by osmotic minipumps and dependent by abrupt withdrawal from pentobarbital. The levels of [3H]MK-801 binding were elevated in rats 24-hr after withdrawal from pentobarbital while there were no changes except in septum and anterior ventral nuclei in tolerant rats. For assessing the role of NMDA receptor in barbiturate action, an NMDA receptor antagonist (MK-801, 2.7 femto g/10 microliters/hr) was co-infused with pentobarbital. The pentobarbital-infused group had a shorter duration of pentobarbital-induced loss of righting reflex (sleeping time) than that of the control group, and MK-801 alone did not affect the righting reflex. However, co-infusion of MK-801 blocked hyperthermia, and prolonged the onset of convulsions induced by t-butylbicyclophosphorothionate (TBPS) in pentobarbital withdrawal rats. In addition, elevated [35S]TBPS binding was significantly attenuated by co-infusion with MK-801. These results suggest the involvement of NMDA receptor up-regulation in pentobarbital withdrawal and that the development of dependence can be attenuated by the treatment of subtoxic dose of MK-801.

Animals↗

PubMed1997

Impaired left ventricular diastolic filling occurs in diabetic patients without atherosclerotic coronary artery disease.

Using left ventriculography, left ventricular diastolic function was studied in 24 diabetic patients who had angina pectoris without atherosclerotic large-vessel coronary artery diseases (group A, 14 patients with exercise-induced ischemic ST-T changes as seen during electrocardiogram; group B, 10 patients without such changes). In groups A and B, the global peak filling rate was significantly less than that in control patients without diabetes or cardiac diseases. The ratio of the global time to the peak filling rate to the diastolic time was higher in both groups A and B than in the control groups. However, the total of time differences, defined as the sum of the time differences between global time to the peak filling rate and each of the three regional time to the peak filling rate, was greater in group A than in either group B or the control patients. Total time difference was similar in group B and the controls. Left ventricular diastolic filling was impaired in diabetic patients without large-vessel coronary artery disease. Impaired diastolic filling was present regionally in patients with ischemic ST-T change but globally in those without such change.

Adult↗

PubMed1997

Inhibitory effects of glibenclamide and pertussis toxin on the attenuation of ischemia-induced myocardial acidosis following ischemic preconditioning in dogs.

Ischemic preconditioning is known to be mediated by several humoral factors, such as adenosine, norepinephrine, and bradykinin. We examined intracellular signal transduction of ischemic preconditioning following receptor stimulation. Alterations in the pH of the ischemic bed were monitored to assess the response of control and ischemic-preconditioned myocardium to glibenclamide and pertussis toxin. Pentobarbital-anesthetized open-chest dogs were subjected to 40 min of ligation of the left anterior descending coronary artery. Ischemic preconditioning was elicited by 25-min periods of coronary ligation followed by 5 min of reperfusion before a 40-min period of ligation. Glibenclamide (0.3 mg/kg)was given i.v. 20 min before the onset of ischemic preconditioning. Pertussis toxin (6-10 micrograms/kg) was given i.v. 3 days before the experiment. Tissue myocardial pH was measured by a glass micro-pH electrode. Ischemia for 5 min decreased myocardial pH and reperfusion returned it to the preischemic levels. Ischemia for 40 min decreased the myocardial pH from 7.43 +/- 0.06 to 6.43 +/- 0.08. Ischemic preconditioning significantly attenuated the decrease in myocardial pH (6.57 +/- 0.06) induced by 40 min of ischemia. Pretreatment with either glibenclamide or pertussis toxin completely abolished the effect of ischemic preconditioning on ischemic myocardial acidosis. Ischemic preconditioning can attenuate ischemia-induced myocardial acidosis in dogs, and this effect is mediated by activation of adenosine triphosphate-sensitive potassium channels and pertussis toxin-sensitive guanosine triphosphate-binding protein.

Acetylcholine↗

PubMed1997

Lipid peroxidation in the pancreas and other organs in streptozotocin diabetic rats.

We studied the relationship between changes in lipid peroxides and those in catalase activity in pancreases, livers and hearts of streptozotocin-induced diabetic rats. Animals were killed 2 or 7 weeks after saline or streptozotocin (32 mg/kg, i.v.) injection. The levels of blood glucose and plasma insulin in the 2-week streptozotocin-treated rats were 176.8+/-20.5 mg/dl and 29.9+/-3.2 microU/ml, respectively. In the pancreas, the lipid peroxide level significantly decreased and the catalase activity significantly increased 2 weeks after streptozotocin injection. These changes recovered after 7 weeks. In the heart, the lipid peroxide level significantly increased without any change of catalase activity 2 weeks after the initiation of diabetes. After 7 weeks, the catalase activity significantly increased and the lipid peroxide level returned to the control level. In the liver, there was no change in the lipid peroxides and catalase in the 2-week streptozotocin-treated rats, whereas the catalase activity significantly increased 7 weeks after the injection. It was suggested that the defense system in the pancreas to oxidative stress may be evoked in an early stage of streptozotocin-induced diabetes.

Animals↗

PubMed1997

Vitamin K2 enhances osteocalcin accumulation in the extracellular matrix of human osteoblasts in vitro.

The role of vitamin K in osteocalcin accumulation in the extracellular matrix of normal human osteoblasts in culture was investigated by using a human intact osteocalcin-specific assay system. Human osteoblasts produced osteocalcin by treatment with 10(-9) M 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) for 20 days in culture. With the addition of vitamin K2 (1.5-5.0 microM), osteocalcin accumulation in the extracellular matrix of the osteoblasts was increased, but the osteocalcin content in the conditioned medium decreased, in comparison with that treated with 10-9 M 1,25(OH)2D3 alone. The enhancement of osteocalcin accumulation induced by vitamin K2 was dependent on the duration of the treatment. The vitamin K2 plus 1,25(OH)2D3-induced osteocalcin accumulation was blocked by the addition of warfarin 2 days before the vitamin treatment. At that time, warfarin significantly reduced the mineralization by osteoblasts in vitro. Osteocalcin accumulated in the extracellular matrix was almost completely precipitated by a low concentration of hydroxyapatite, 10 mg/ml. Moreover, the gamma-carboxyglutamic acid (Gla)-containing osteocalcin level was increased by the vitamin K2 plus 1,25(OH)2D3 treatment. These results proved that vitamin K2 increased Gla-containing osteocalcin, which accumulated osteocalcin in the extracellular matrix, and facilitated mineralization in vitro. Vitamin K2 also enhanced the 1,25(OH)2D3-induced osteocalcin mRNA level, but vitamin K2 alone did not show osteocalcin mRNA expression. We thus demonstrated that vitamin K2 enhanced not only the accumulation of Gla osteocalcin, but also the osteocalcin production induced by 1,25(OH)2D3 in human osteoblasts in culture.

Bone Density↗

PubMed1997

An evaluation of neuromuscular reversal with edrophonium in a patient with malathion intoxication.

We evaluated the neuromuscular reversal with edrophonium using peripheral nerve stimulator and recorder in a patient with malathion intoxication. Edrophonium 10 mg i.v. caused an increase in single twitch tension by 76% of the control during the recovery phase from an acute cholinergic crisis 16 days after ingestion of malathion solution. The present study indicated that edrophonium test seems to be a reliable monitoring in evaluating neuromuscular reversal in the patient with acute malathion insecticide poisoning.

Adult↗

PubMed1997

Apolipoprotein E Sendai (arginine 145-->proline): a new variant associated with lipoprotein glomerulopathy.

Lipoprotein glomerulopathy (LPG) is a novel disease characterized by proteinuria, lipoprotein thrombi in the glomeruli, and increased concentration of plasma apolipoprotein (apo) E. It is believed that a genetic disorder of apo E may be present and associated with the disease. Three patients with LPG were examined in this study. The patients' DNA sequences were analyzed, and a nucleotide G to C point mutation in exon 4 of the apo E gene was confirmed in each patient. This missense mutation denotes amino acid substitution of the proline residue for arginine residue at position 145 of apo E. This variant (apo E Sendai) may cause a marked molecular conformational change of the apo E. These findings suggest that a novel variant is etiologically related to LPG.

Aged↗

PubMed1997

The prognosis of fetuses with transient nuchal translucency in the first and early second trimester.

OBJECTIVE: The purpose of this study was to evaluate the prognosis of fetuses with transient nuchal translucency before 15 weeks of gestation. STUDY DESIGN: A nuchal translucency's measurement of > or = 5 mm was considered abnormal. In the period from 1994 to 1995, twelve fetuses were diagnosed at our institution with nuchal translucency. The fetuses all underwent karyotyping and a complete ultrasonographic search for any associated anomalies and a resolution of nuchal translucency at 1-2 week gestational age intervals. RESULTS: Five cases ('Transient NT') demonstrated transient nuchal translucency. Seven cases ('Persistent NT') demonstrated persistent nuchal translucency. The 984 cases with no or less than 5 mm of nuchal translucency (control group) gave birth at the same time. The mean initial week of diagnosis was 12.0 +/- 1.6 weeks in 'Transient NT', and 13.6 +/- 1.8 weeks in 'Persistent NT'. The mean maternal age was 30.8 +/- 6.3 years old in 'Transient NT', 28.9 +/- 3.0 years old in 'Persistent NT', and 30.5 +/- 43 years old in the control group. Abnormal karyotypes were detected in one case in 'Transient NT', and in four cases in 'Persistent NT'. Structural malformations were detected in two cases (40%) in 'Transient NT', seven cases (100%) in 'Persistent NT', and 30 cases (3.0%) in the control group. CONCLUSIONS: Regardless of the spontaneous resolution of abnormal nuchal translucency, there was a high association with both karyotypical and structural abnormalities, and the prognosis of such cases was generally poor, especially persistent NT's prognosis.

Adult↗

PubMed1997

[Successful surgical treatment of aortic regurgitation due to annuloaortic ectasia and mitral regurgitation caused by tendon rupture in a case of osteogenesis imperfecta].

A 54-year-old man presented with osteogenesis imperfecta complicated with both aortic regurgitation due to annuloaortic ectasia and mitral regurgitation secondary to tendon rupture. He had spinal and carpal deformities in his childhood, and heart murmurs were identified at the age of 25. He was admitted complaining of dyspnea on effort. His height was 142 cm and his weight was 46 kg. He had kyphosis, scoliosis and carpal deformity. Blue sclera was not observed. Chest radiography showed cardiomegaly and lung congestion. Echocardiography showed annuloaortic ectasia, mild aortic regurgitation, and serious mitral regurgitation due to postero-apical tendon rupture. Bone deformity and his statues were indicative of osteogenesis imperfecta. He received modified Bentall and mitral valve replacements.

Aortic Valve Insufficiency↗

PubMed1997

Glutamate in opioid dependence.

The present review will concentrate on a discussion of recent investigations which implicate a critical linkage of three facets of the central nervous system mediation of opioid dependence, as evidenced by expression of acutely-precipitated withdrawal events. These are the kappa-opioid receptor subtype, the glutamatergic neuronal system and a specific brain locus, the locus coeruleus. The impetus for this line of investigation derives from a recognition that opioid analgesics, such as butorphanol (Stadol), exhibit a markedly different profile of activity at opioid receptors than does morphine yet have abuse liability and cause dependence readily. Emphasis will be placed on demonstration of a rodent model in which butorphanol administration induces dependence through a unique (in comparison with morphine) activation of the kappa-opioid receptor. The use of in vivo microdialysis techniques clearly identifies, in this model, that acutely-precipitated withdrawal from dependence on butorphanol results in focal increases in extracellular levels of glutamate within the locus coeruleus, and that the withdrawal syndrome can be mimicked by intracerebroventricular administration of exogenous glutamate, acting through the N-methyl-D-aspartate glutamate receptor subtype. The data confirm the participation of glutamate as a general phenomenon in opioid dependence, identify the locus coeruleus as a primary site for glutamatergic mediation of dependence, and suggest novel aspects to the neuropharmacology of opioid dependence with respect to the role of the kappa-opioid receptor.

Analgesics, Opioid↗

PubMed1997

Tricuspid valve infectious endocarditis associated with dental treatment.

A 52-year-old man with neither congenital heart disease nor history of drug abuse had a spiking fever after dental treatment and was diagnosed with pneumonia at a local clinic. He was treated with antibiotics and his fever went down. Ten months later, he had again pyrexia and suffered from congestive heart failure. He admitted to our hospital and tricuspid valve endocarditis was proved by echocardiography. He was treated with penicillin. However, during the treatment, he developed a pulmonary embolism. So he underwent surgical treatment. We should take dental treatment into account one of predisposing causes of tricuspid endocarditis.

Anti-Bacterial Agents↗

PubMed1997

[Male sterility].

Recently several studies have suggested a decline in the quality of semen. About half of the infertile causes are in men, the rate is increasing in the infertile couples. There are some therapy for the male sterility; medication, surgery or assisted reproductive technology (ART). Medicinal effects are not expected, and surgical cases are localized for indication. Moreover, since most of male sterility are idiopathic insufficiency of spermatogenesis, a recent tendency in the male sterile therapy is ART such as IVF-ET, ICSI, TESE, etc.

Humans↗

PubMed1997

[Successful treatment of interstitial pneumonia with lipo-PGE1 and pentoxifylline in a patient with dermatomyositis].

Interstitial pneumonia complicated with dermatomyositis sometimes shows a resistance to high dose steroid therapy and a fatal course particularly in patients without showing the elevation of creatine kinase. We experienced a 48 year old woman who developed heliotrope rash, Gottron's sign, multiple cutaneous ulcers, and dyspnea on exertion. These symptoms were resistant to low dose steroid therapy. Serum levels of creatine kinase were normal. Anti-nuclear antibodies and anti-Jo-1 antibody were negative. High resolution CT scan of the chest showed areas of multiple air space consolidation and subpleural linear shadows. Lung biopsy performed under video-assist thoracosurgery revealed diffuse alveolitis with scattered lymphoid folicules and mild accumulation of macrophages in the alveolar spaces. There were no honey-combing. These features were compatible with "non-specific interstitial penumonia" proposed by Katzenstein, 1995. The patient was treated with 10 micrograms lipo-PGE1, PGE1 incorporated in lipid microspheres, and 300 mg pentoxifylline, which resulted in a dramatic improvement of both interstitial pneumonia and cutaneous ulcers. The present case suggested a novel strategy for the treatment of interstitial pneumonia.

Alprostadil↗

PubMed1997

[The efficacy of postural drainage in a case of pulmonary edema following cholecystectomy].

An 81-year-old man underwent percutaneous transluminal gallbladder drainage. As the drain was accidentally removed six days later, he received cholecystectomy. After the operation, he developed hypotension, hypoxemia and ST level depression on ECG. He received artificial ventilation and cathecholamines. His chest CT showed marked pulmonary edema, and total protein of the edema-fluid was 3.3 g.dl-1. These findings suggested permeability pulmonary edema. He received postural drainage of the edema-fluid, and the pulmonary oxygenation was gradually improved. He was weaned from artificial ventilation on the 6th ICU day and discharged the next day.

Aged↗

PubMed1997

Improvement of impaired glucose tolerance by oral administration of vanadyl sulfate by gavage in streptozotocin-induced diabetic rats.

We examined the effect of oral administration of vanadyl sulfate by gavage on the levels of blood glucose and plasma insulin during oral glucose tolerance test (OGTT) in diabetic rats. Diabetes was induced by intravenous injection of streptozotocin at the dose of 32 mg/kg. Nondiabetic control animals were injected with an equal volume of saline. Vanadyl sulfate at a dose of 25, 50, or 75 mg/kg was given orally by gavage for 2 weeks, starting 12 hours after streptozotocin injection. When vanadyl sulfate was given twice a day, half of the one-day-dosage was given in the morning and the remaining half in the evening. Glucose tolerance test with 5 g/kg of glucose was carried out 2 weeks after administration of vanadyl sulfate. The fasting the blood glucose level in the diabetic rats was higher than that in the non-diabetic rats, whereas the plasma insulin level in the diabetic rats was lower. An increase in blood glucose seen in the glucose tolerance test was significantly greater in the diabetic rats than in the non-diabetic rats. The level of plasma insulin was increased by glucose tolerance test in the non-diabetic rats, while it was not changed in diabetic rats. Oral administration of vanadyl sulfate by gavage significantly improved the impaired glucose tolerance in the the diabetic rats in a dose-dependent manner without any change in plasma insulin level. In conclusion, oral administration of vanadyl sulfate by gavage is effective on impaired glucose tolerance in streptozotocin-induced diabetic rats.

Animals↗

PubMed1996

Precipitated kappa-opioid receptor agonist withdrawal increase glutamate in rat locus coeruleus.

Extracellular fluid levels of excitatory amino acids (glutamate, Glu; and aspartate, Asp) in the locus coeruleus and the behavioral signs during naloxone-precipitated withdrawal from kappa-opioid receptor agonists, butorphanol and (5 alpha, 7 alpha, 8 beta) -(+)-N-methyl-N-[7-(1-pyrrolidinyl)-1-oxaspiro[4,5]dec-8-yl]-be nzaneacetamide (U-69,593), were investigated by in vivo microdialysis. Increases in levels of Glu, but not of Asp, were noted after naloxone (12 or 48 nmol/5 microliters, locus coeruleus)-precipitated withdrawal in the rats which had been intracerebroventricularly infused with butorphanol (26 nmol/1 microliters/h) or U-69,593 (26 nmol/10 microliters/h) for 3 days. The Glu levels in the locus coeruleus increased following administration of naloxone before and during the first 15-min sample after the precipitation of withdrawal in the butorphanol- or U-69,593-dependent rats. Furthermore, behavioral evidence of withdrawal (teeth-chattering, wet-dog shakes, etc.) was detected following the naloxone challenge in the butorphanol- and U-69,593-infused rats, but not in saline-infused controls. These results provide direct evidence to support the role of excitatory amino acids within the locus coeruleus in butorphanol or U-69,593 withdrawal.

Analgesics↗

PubMed1996

The untranslated first exon 'exon 0S' of the rat estrogen receptor (ER) gene.

Recently, we have isolated the untranslated first exon 'exon ON' of the rat estrogen receptor (ER) gene from the liver by the use of the 5'-rapid amplification of cDNA ends (5'-RACE) method. To investigate the existence of other untranslated first exon(s), we further analyzed the 5'-untranslated region (UTR) of ER mRNA in the rat liver in this study. Total RNA from the livers of 8-week-old male Wistar rats was subjected to 5'-RACE with the antisense primers located in exon 1 of the rat ER gene. The inserts of four clones (clones 3, 4, 7 and 8) were sequenced. The nucleotide sequences of the clones revealed the existence of a previously unidentified untranslated first exon (we termed it 'exon OS') which was spliced onto exon I of the rat ER mRNA. The distribution of ER mRNA containing 'exon OS' (ER mRNA (OS-1)) in several brain regions and various peripheral tissues of 8-week-old male and female Wistar rats was further analyzed by the use of the reverse transcription-polymerase chain reaction. ER mRNA (OS-1) was found to be widely distributed in the rat brain and peripheral tissues. The distribution of the message was different from that of ER mRNA containing exon 0 (the first reported 5'-UTR form of rat ER mRNA) or of ER mRNA with exon ON which was reported in our recent report. These results indicate that (1) 'exon OS' is a novel untranslated first exon of the rat ER gene, (2) rat ER mRNAs possess at least three forms of 5'-UTRs which are exon 0, exon ON, and exon OS, (3) the tissue specific expression of ER is regulated, at least in part, by the usage of differential promoters in the rat.

Alternative Splicing↗