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Biomedical subjects

K Kosaka

Publications and source records attributed to K Kosaka.

At least 91 records · Page 5Linked to original sources
PubMed1998

How simple is the organization of the olfactory glomerulus?: the heterogeneity of so-called periglomerular cells.

Recent progress in the studies of the olfactory system, especially in the molecular biological studies, makes it one of the useful sensory model systems for understanding neural mechanisms for the information processing. In the olfactory bulb, the primary center of the olfactory system, glomeruli are regarded as important functional units in the transmission of odorant signals and in processing the olfactory information, but have been believed to be composed by only a small number of neuronal types and thus to be simple in their neuronal and synaptic organization. However, accumulating morphological data reveal that each type of neurons might further consist of several different subpopulations, indicating that the organization of glomeruli might not be so simple as it was believed. Here we describe an aspect of the structural organization of glomeruli, focusing on the heterogeneities of periglomerular neurons in mammalian main olfactory bulb.

Animals↗
PubMed1998

Baseline factors affecting the efficacy of troglitazone on plasma glucose in Japanese patients with non-insulin-dependent diabetes mellitus.

In order to assess the relationship between clinical efficacy of troglitazone on glycemic control and baseline characteristics of patients with NIDDM, we analyzed the data of ten clinical studies on troglitazone carried out in Japan. The study consisted of 604 subjects with NIDDM whose glycemic control had been unsatisfactory (fasting plasma glucose (FPG) > or = 8.3 mM) with diet or sulfonylureas (SU) and who had been assigned to one of ten clinical studies at a dose of 400 mg/day troglitazone for 12-16 weeks. In patients who had been treated with SU, troglitazone was given in combination with the SU drugs. The percentage decrease in FPG was adopted as the index of clinical efficacy. The relationship between this index and various baseline parameters of patients was analyzed. It was found that FPG and triglycerides decreased significantly with troglitazone (pre- and post-treatment: FPG 10.3 +/- 2.0 and 8.7 +/- 2.2 mM; triglyceride 1.82 +/- 1.27 and 1.51 +/- 0.99 mM, respectively). The percentage decrease in FPG after treatment did not differ between groups treated with troglitazone alone and those treated with troglitazone in combination with SU drugs (14.7 vs. 15.5%). Patients were classified into two groups according to the percentage decrease in FPG, greater and less than 15%. The group with greater decrease in FPG included more females and had the older mean age, greater body mass index (BMI), higher pre-treatment FPG, and higher pre-treatment C-peptide values. In the multiple regression analysis, female gender, age, BMI and pre-treatment FPG level were selected as the variables for the best regression model. The results indicate that troglitazone at 400 mg/day decreased FPG significantly in patients with NIDDM and the percentage decrease in FPG was positively correlated with female gender, higher pre-treatment FPG, older age, greater BMI and higher C-peptide level. The results suggest that this drug is more effective in patients with greater insulin resistance, in keeping with its proposed mode of effect.

Aged↗
PubMed1998

A novel mutation found in an adrenoleukodystrophy patient who underwent bone marrow transplantation.

We identified a novel mutation, L322P, in a patient with X-linked adrenoleukodystrophy (ALD) who underwent bone marrow transplantation (BMT). An identification of the ALD gene mutation enabled us to employ an approach not dependent on the use of radioisotopes for detecting mixed chimerism. This assay could show more than 99.0% of the patient's peripheral white blood cells were replaced by the donor's cells.

Adrenoleukodystrophy↗
PubMed1998

HLA-DRB1 alleles contribute to determining the prognosis of Japanese diabetes mellitus positive for antibodies to glutamate decarboxylase.

Diabetes mellitus positive for antibodies to glutamate decarboxylase is heterogeneous as far as the degree of impairment of endogenous insulin release, though antibodies to glutamate decarboxylase are the most useful marker for future insulin deficiency. To investigate what determines the prognosis of diabetes mellitus positive for antibodies to glutamate decarboxylase, we measured HLA-DRB1 alleles in three groups: 77 cases of insulin-dependent diabetes mellitus (IDDM), 44 of non-insulin-dependent diabetes mellitus (NIDDM) with secondary failure of oral hypoglycemic therapy, and 22 of NIDDM well controlled by diet and/or sulfonylurea agents. The proportion of susceptible and resistant alleles to IDDM determined the degree of insulin deficiency, and comparison of IDDM to NIDDM well controlled by diet and/or sulfonylurea agents revealed significant differences in DRB1*0405 (P < 0.05; RR = 2.82 and RR = 0.89, respectively) and DRB1*1502 (P < 0.001; RR = 0.02 and RR = 2.19, respectively). This study revealed that HLA-DRB1 alleles contribute to determining the prognosis of Japanese diabetes mellitus positive for antibodies to glutamate decarboxylase.

Adolescent↗
PubMed1998

A case of depressive disorder with neuronal heterotopia.

We describe a case of depressive disorder with neuronal heterotopia. The patient, a 55-year-old woman, had a history of depressive episodes since the age of 53. Magnetic resonance imaging (MRI) disclosed bilateral periventricular heterotopia. The patient had not experienced any epileptic episodes, and an electroencephalogram did not reveal any epileptic discharge. Single photon emission computed tomography (SPECT) disclosed diffuse cerebral hypoperfusion. This is the first report on a case of depression with neural migration disorder. Patients with neural migration disorders can be detected more frequently with the increasing use of MRI.

Cell Movement↗
PubMed1998

Recent advances in dementia research in Japan: non-Alzheimer-type degenerative dementias.

In this article, we review recent reports by Japanese researchers on non-Alzheimer-type degenerative dementias. These dementias can be classified into the following subtypes: dementias with Lewy bodies, including diffuse Lewy body disease, dementias with neurofibrillary tangles, dementias with glial tangles, including progressive supranuclear palsy and corticobasal degeneration, argyrophilic grain dementia, frontotemporal dementias including Pick's disease; dementias with degeneration of subcortical nuclei, including Huntington's disease and, last, unclassified dementias. Recently, these various forms of dementia have received much attention in Japan, as elsewhere.

Cerebral Cortex↗
PubMed1998

Japanese Creutzfeldt-Jakob disease patients exhibiting high incidence of the E200K PRNP mutation and located in the basin of a river.

Seven cases with Creutzfeldt-Jakob disease (CJD) located in the basin of the Fuji river (Fuji area) in Japan were examined genetically and clinicopathologically. The onset of the disease was between 1989 and 1995. All cases were from different families, although 3 cases were family members of previously reported CJD patients. They had clinical and/or neuropathological features, corresponding to subacute spongiform encephalopathy. Five of the 7 cases, including the 3 familial cases, had the E200K mutation in the gene encoding prion protein (PRNP). It is suggested that there is a small cluster of CJD patients with a founder effect of the E200K mutation in the Fuji area, because the incidence of CJD with the E200K mutation appears to be much higher in this area than other areas in Japan. The disease penetrance of the 5 cases with the E200K mutation seems to be low, and they may have an age-related incidence in the Fuji area. These findings support the hypothesis that the phenotypes of CJD patients with the PRNP mutations are linked to the position of the mutation, but not related to ethnic or environmental factors.

Aged↗
PubMed1998

Changes in work performances in obstructive sleep apnea patients after dental appliance therapy.

The effects of dental appliances on work performances of obstructive sleep apnea syndrome (OSAS) is not well examined. This study evaluated the polysomnographic and psychological findings before and after therapy. Nine patients were diagnosed OSAS by nocturnal polysomnography. The psychological batter, was performed from 13:00 to 14:00, which consisted of Uchida-Kraepelin psychodiagnostic test (U-K's test) and Bourdon's cancellation test (Bourdon's test). Approximately 3 months after the treatment, the examinations were performed. Apnea and desaturation index decreased significantly after the therapy. In addition, sleep architecture improved after the therapy compared with that before the therapy. Dysfunction of task performances, such as mean level of work amounts in U-K's test, mean error, mean performance time and mean deviation in Bourdon's test improved after therapy. We conclude that dental appliances therapy is effective not only to apnea but also to work performance in OSAS.

Adult↗
PubMed1998

Brain imaging of affective disorders and schizophrenia.

We review recent findings in human brain imaging, for example, which brain areas are used during perception of colors, moving objects, human faces, facial expressions, sadness and happiness etc. One study used fluorine-18-labeled deoxyglucose positron emission tomography (PET) in patients with unipolar depression and bipolar depression, and found hypometabolism in the left anterolateral prefrontal cortex. Another study reported increased regional cerebral blood flow in the amygdala in familial pure depressive disease. Using 11C-glucose PET, we reported that the glutamic acid pool was reduced in cortical areas of the brain in patients with major depression. We also found that the thalamic and cingulate areas were hyperactive in drug-naive (never medicated) acute schizophrenics, while the associative frontal, parietal, temporal gyri were hypoactive in drug-naive chronic schizophrenics. Brain biochemical disturbances of schizophrenic patients involved glutamic acid, N-acetyl aspartic acid, phosphatidylcholine and sphingomyelin which are important chemical substances in the working brain. The areas of the thalamus and the cingulate which become hyperactive in acute schizophrenic patients are important brain areas for perception and communication. The association areas of the cortex which become disturbed in chronic schizophrenia are essential brain areas in human creativity (language, concepts, formation of cultures and societies) and exist only in human beings.

Bipolar Disorder↗
PubMed1998

Pancreatic exocrine dysfunction associated with mitochondrial tRNA(Leu)(UUR) mutation.

We report on pancreatic exocrine dysfunction in families that have the mitochondrial tRNA(Leu)(UUR) gene mutation. These families exhibited maternally inherited diabetes mellitus (DM) and an A to G substitution at nt 3243 of the mitochondrial tRNA(Leu)(UUR) gene (A3243G mutation). Pancreatic necropsy samples from one proband showed accumulation of degenerated mitochondria in pancreatic acinar cells. Pancreatic exocrine dysfunction was recognised by a functional pancreatic study. This study indicates that exocrine pancreatic dysfunction may be associated with the A3243G mutation.

4-Aminobenzoic Acid↗
PubMed1998

Lack of association between neuroleptic malignant syndrome and polymorphisms in the 5-HT1A and 5-HT2A receptor genes.

OBJECTIVE: The molecular basis of neuroleptic malignant syndrome is unclear, but studies suggest that genetic factors are involved in its pathogenesis. Considering possible involvement of the serotonergic system in neuroleptic malignant syndrome, the authors examined the association between neuroleptic malignant syndrome and polymorphisms of the 5-HT1A and 5-HT2A receptor genes. METHOD: The authors examined the frequencies of gene polymorphisms in the 5-HT1A (Arg219Leu) and 5-HT2A (Thr25Asn and His452Tyr) receptor genes in 29 patients previously diagnosed with neuroleptic malignant syndrome, 94 neuroleptic-treated patients with schizophrenia who had no history of neuroleptic malignant syndrome, and 94 healthy comparison subjects. Polymerase chain reaction and restriction fragment length polymorphism analyses were used to screen gene mutations. RESULTS: No polymorphic allele was detected in the patients who had experienced the neuroleptic malignant syndrome. CONCLUSIONS: The authors cannot conclude that polymorphisms in the 5-HT1A and 5HT2A receptor genes are factors determining susceptibility to the neuroleptic malignant syndrome.

Adult↗
PubMed1998

Diffuse Lewy body disease.

Diffuse Lewy body disease (DLBD) has been studied from various viewpoints, and although clinical diagnostic criteria for DLBD have been proposed, the diagnosis remains difficult. It has been reported that DLBD is the second most frequent degenerative dementia among the elderly, following Alzheimer-type dementia. Many DLBD cases, however, are clinically misdiagnosed. Therefore, the search for diagnostic markers for DLBD must continue. Very recently, "dementia with Lewy bodies" (DLB) was proposed as a generic term including DLBD and similar disorders. Cortical Lewy bodies are the most important pathological marker for diagnosis of DLB. At this time, however, the mechanism of cortical Lewy body formation is yet to be disclosed.

Aged↗
PubMed1997

Selective association of S100A6 (calcyclin)-immunoreactive astrocytes with the tangential migration pathway of subventricular zone cells in the rat.

In adult rodents, proliferating cells in the subventricular zone of lateral ventricle tangentially migrate into the olfactory bulb, where they become the interneurons. The present immunocytochemical analysis revealed that S100A6 (calcyclin), a specific calcium-binding protein of the S100 family, is restrictedly distributed in some astrocytes in the tangential migration pathway of the rat. These results suggest that a particular type of astrocytes containing S100A6 is associated with the tangential migration pathway.

Animals↗
PubMed1997

Reduction of telencephalin immunoreactivity in the brain of patients with Alzheimer's disease.

Telencephalin (TLN) is a cell adhesion molecule expressed in the telencephalon of the mammalian central nervous system. We have investigated immunohistochemically the expression of TLN in human brain tissue from control subjects and patients with Alzheimer's disease (AD). In control brain, neuropil of the gray matter was stained diffusely with the anti-TLN antibody. TLN immunoreactivity was markedly decreased in the brain of AD patients, particularly in the hippocampal formation.

Aged↗