Search PubMed⌕ Search

Biomedical subjects

K Yamada

Publications and source records attributed to K Yamada.

At least 307 records · Page 17Linked to original sources
PubMed2001

Cardiac dysfunction because of secondary hemochromatosis caused by congenital non-spherocytic hemolytic anemia.

Most patients diagnosed with secondary hemochromatosis have had repeated blood transfusions. Cardiac failure accounts for approximately one-third of the deaths associated with hemochromatosis. Liver dysfunction or hormonal disorders such as diabetes generally precede cardiac failure. A 23-year-old woman with hemochromatosis had, despite significant left ventricular dysfunction, liver function within the normal range on biochemical evaluation. She was treated for congestive heart failure and given desferoxamine intravenously. She did not have primary hemochromatosis, and had not received multiple blood transfusions or iron supplement. As a child the patient had been diagnosed with congenital non-spherocytic hemolytic anemia not requiring transfusion; thus, this is a unique case of secondary hemochromatosis.

Adult↗
PubMed2001

Possible involvement of calcium-calmodulin pathways in the positive chronotropic response to angiotensin II on the canine cardiac sympathetic ganglia.

We investigated the ganglionic effects of angiotensin II (Ang II) and the signal transduction involved in the cardiac sympathetic ganglia by the direct administration of agents to the ganglia through the right subclavian artery and monitoring the heart rate as an indicator of the ganglionic function in pithed dogs. Ang II given i.a. caused increases in the heart rate, which was inhibited by the treatment with the AT1-receptor antagonist forasartan, but not by the AT2-receptor antagonist PD-123319. The stimulation by Ang II, but not by acetylcholine, was inhibited after treatment with an inhibitor of phospholipase C, U-73122; a cell-permeant modulator of the Ins(1,4,5)P3 receptors, 2-aminoethoxydiphenyl borate; an intracellular calcium and calcium-associated protein kinase inhibitor, HA-1077; calmodulin (CaM) inhibitor, W-7; Ca2+/CaM-dependent protein kinase II inhibitor, KN-93; a selective protein kinase C inhibitor, calphostin C; and Na+H+ exchange inhibitor, dimethylamiloride. These results suggest that Ang II stimulates the ganglionic transmission at postsynaptic sites via the activation of AT1 receptor coupled to either activation of phospholipase C, phosphoinositide hydrolysis and subsequent increase in intracellular Ca2+ and activation of protein kinase C and Ca2+/CaM kinase II, although this ganglionic stimulation seems to involve, at least in part, the protein kinases-dependent increase of amiloride-sensitive Na+ inflow.

Amiloride↗
PubMed2001

Development of assay system for immunoglobulin production regulatory factors using whole cell cultures of mouse splenocytes.

We tried to establish an assay system for screening and assessment of immunoregulatory factors using whole cell cultures of mouse splenocytes and found that splenic adhesive cells markedly increased immunogobulin (Ig) production of splenocytes. In the absence of adhesive cells, lipopolysaccharides, pokeweed mitogen, and phytohemagglutinin stimulated the production of IgA, IgG, and IgM in a class-dependent manner. Adhesive cells increased more markedly Ig production of splenocytes stimulated with these mitogens. When mouse splenocytes were cultured with milk proteins in the absence of adhesive cells, lactoferrin, beta-lactoglobulin, alpha-casein, and beta-casein stimulated IgA and IgG production. Adhesive cells increased IgA production of splenocytes stimulated with milk proteins, especially. These results suggest that the assay system is useful for assessment of Ig production-regulating factors.

Animals↗
PubMed2001

Dietary manipulations of body fat-reducing potential of conjugated linoleic acid in rats.

To study whether the body fat-reducing potential of conjugated linoleic acid (CLA) could be increased through dietary manipulations, the effects of the combination of CLA with different proteins, fats, and sesamin were examined in rats. Male rats were fed diets containing 1% CLA or linoleic acid (LA) in combination with different proteins (20% of casein or soybean protein), fats (7% perilla oil or soybean oil) and 0.2% sesamin (SES) for 3 or 4 weeks. When the dietary fat source was soybean oil, CLA, as compared with LA, significantly reduced weights of epididymal and perirenal adipose tissues, irrespective of the dietary protein sources. However, the highest reducing effect was shown when soybean protein was given as a protein source. SES stimulated the reduction of epididymal and perirenal adipose tissue weights in both protein diets. In contrast, CLA increased the weight of brown adipose tissue, and SES further increased it in combination with soybean oil but not with perilla oil. No effect of dietary manipulation was observed on serum leptin and TNF-alpha levels. Thus, the body fat-reducing potential of CLA can be increased by an appropriate combination with food factors that may stimulate fatty acid beta-oxidation.

Adipose Tissue↗
PubMed2001

Oxidative stress by visible light irradiation suppresses immunoglobulin production in mouse spleen lymphocytes.

In this study, we attempted to induce the oxidative stress in mouse spleen lymphocytes with visible light irradiation and examined the effects of lipid peroxidation on immunoglobulin (Ig) production. The spleen lymphocytes were isolated from 8-week-old male balb/c mice and irradiated with 300 W visible light. When the cells were cultured for 72 hr, Ig contents in culture supernatants were decreased gradually by irradiation for over 30 min. The cell viability was also lowered by the irradiation. Intracellular phosphatidylcholine hydroperoxide (PCOOH) levels and thiobarbituric acid-reactive substances (TBARS) values in culture supernatants were measured as indices of lipid peroxidation and we found that Ig production by mouse spleen lymphocytes was suppressed accompanied with the progress of peroxidation of intracellular phospholipids. Cell membrane fluidity was also significantly decreased, but the intracellular Ig level was not changed in the irradiated cells. These results suggest that the peroxidation of intracellular lipids is a cause of the suppression of Ig production by mouse spleen lymphocytes via lowering cell viability and suppressing Ig synthesis and secretion.

Animals↗
PubMed2001

[A clinical study of the usefulness of assessing dyspnea in healthy elderly subjects].

Dyspnea is a major clinical symptom of various respiratory diseases. However, no objective assessment of dyspnea on exertion (DOE) in elderly subjects has been established yet. Furthermore, the factors which may influence DOE in healthy elderly subjects have not yet been precisely elucidated. An oxygen cost diagram (OCD), which was originally developed by McGavin (1978), is one of the methods of assessing dyspnea on exertion in a semi-quantitative way, although it is still uncertain which factor (s) might influence the changes in OCD values. The present study was, therefore, undertaken to study; 1) whether OCD values are useful for the assessment of DOE in elderly subjects, and 2) the possible factors (s) which might contribute to changes in OCD values in these patients. The total number of subjects which were enrolled in the present study was 818, consisting of 355 men and 463 women, whose mean age was 76.4 years old, was studied. Spirometry, arterial blood gases and OCD values were measured on the same day. The OCD value and FEV(1.0) declined linearly with advanced aging. It was found that the factors which significantly reduce OCD values were as follows: aging, vital capacity, FEV(1.0), and maximal voluntary ventilation (MVV). The odd ratio which contributes to changes in OCD values was calculated. It appeared that there was a gender difference: when the odd ratio of OCD values of less than 70 was taken as 1 in the men, the odd ratio in women was calculated as 1.42. The odd ratio increased with advancing age; when the value in the 65~69 year-old group was 1, the odd ratios in the 85~89 year-old and 90~94 year-old groups were in approximately 6 and 8, respectively. Similarly, the odd ratio increased parallel with reduction in MVV. From these results, we conclude that the OCD value is reliable, simple and the best method of evaluating dyspnea in elderly subjects semi-quantitatively, and both the minute ventilatory volume and age are closely related with changes in OCD values.

Activities of Daily Living↗
PubMed2001

Application of short-time magnetic resonance examination for intervertebral disc diseases in dogs.

The usefulness of magnetic resonance (MR) is already established, but it has a disadvantage of requiring a long scanning time. A short-time examination is more or less needed so as to be more practical in veterinary clinics. A protocol of the short-time MR examination was devised based on parameters determined, and validity of the protocol was assessed through the diagnosis of clinical cases with intervertebral disc diseases. With this protocol, it was possible to complete an MR examination for the spine within 15 min. The MR images and myelographic findings were correlated well in this study, suggesting the short-time protocol of MR examination can be used in the clinical diagnosis of spinal diseases.

Animals↗
PubMed2001

Investigation of the short-term effect of chemonucleolysis with chondroitinase ABC.

Chondroitinase ABC (C-ABC) is expected to be a novel agent for chemonucleolysis. The effect of C-ABC was investigated by magnetic resonance (MR) and radiograph. C-ABC was administered into the lumbar intervertebral disks on the clinically normal beagles (n=5), in a dose of 50 microl (12.5 units as C-ABC). MR scans were performed pre-dose, and 1, 3, 7, 14 and 28 days after administration of C-ABC, and the signal intensity (SI) of the nucleus pulposus was measured. Radiographs were taken pre-dose, and 1, 2, 3, 4, 5, 6, 7, 14 and 28 days post-dose, to evaluate narrowing of the disk space in terms of height index (HI). In addition, the quantity of the chondroitin sulfate (CS) and the hyaluronic acid (HA) in the nucleus pulposus were measured by high performance liquid chromatography on day 28 after dosing. SI and HI continuously decreased, following the injection to 37.1% and 78.9% of the pre-dose values, respectively. Statistically significant differences (p<0.01) were observed between the C-ABC group and the control group in the respects on day 1 post-dose. CS and HA contents of the nucleus pulposus were noted to be significantly decreased on day 28 (p<0.01) in the treated group. This agent proved to degenerate proteoglycans in the nucleus pulposus, thus progressively reducing the interdiskal pressure from day 1 post-dose onwards. It is concluded that C-ABC is expected to afford its efficacy from early in the course of chemonucleolysis.

Animals↗
PubMed2001

Sequence analysis of candidate genes for common susceptibility to type 1 and type 2 diabetes in mice.

Although type 1 and type 2 diabetes are regarded as clinically distinct diseases, several lines of evidence have suggested common genetic factors between the two types of diabetes. The non-obese diabetic (NOD) mouse, an animal model of type 1 diabetes, and the Nagoya-Shibata-Yasuda (NSY) mouse, a model of type 2 diabetes, are derived from the same outbred colony, Jcl:HCR, suggesting a shared susceptibility between the two types of diabetes in mice. Genetic as well as functional studies have supported the possibility that Tcf2, which encodes the transcription factor, hepatocyte nuclear factor 1beta (HNF-1beta), is a candidate gene for the common susceptibility between NSY and NOD mice. Txn, encoding thioredoxin which is a redox (reduction/oxidation)-active protein, is also a positional and functional candidate for a common susceptibility gene. To investigate whether either of these two genes is a common susceptibility gene, the coding nucleotide sequences of these two genes were compared among the NSY, NOD and control C3H strains. The coding sequence of Tcf2 of the NOD mouse was identical to that of the C3H mouse, but was different from that of the NSY mouse. The coding sequence of Txn was identical in the three strains. These data suggest that neither of the two genes is a common susceptiblity gene between type 1 and type 2 diabetes in mice.

Animals↗
PubMed2001

Fluorescence-quenching phenomenon by photoinduced electron transfer between a fluorescent dye and a nucleotide base.

Fluorescently labeled oligonucleotide probes have been widely used in biotechnology, and fluorescence quenching by the interaction between the dyes and a nucleobase has been pointed out. This quenching causes big problem in analytical methods, but is useful in some other cases. Therefore, it is necessary to estimate the fluorescence quenching intensity under various conditions. We focused on the redox properties of some commercially available fluorescent dyes, and investigated dye-nucleotide interactions between a free dye and a nucleotide in aqueous solution by electrochemical and spectroscopic techniques. Our results suggested that the quenching was accompanied by photoinduced electron transfer between a thermodynamically quenchable excited dye and a specific base. Several kinds of fluorescent dyes labeled to the 5'-end of oligonucleotide C10T6 were prepared, and their quenching ratios compared upon hybridization with the complementary oligonucleotide A6G10. The quenching was completely reversible and their efficiencies depended on the attached fluorophore types. The fluorescence of 5-FAM, BODIPY FL or TAMRA-modified probe was strongly quenched by hybridization.

Algorithms↗
PubMed2001

Lower mortality in patients with the DD genotype of the angiotensin-converting enzyme gene after acute myocardial infarction.

OBJECTIVE: The angiotensin-converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism has been associated with different serum ACE concentrations and cardiac ACE activity. We assessed whether the ACE gene I/D polymorphism influenced cardiac mortality in Japanese patients with acute myocardial infarction. METHODS AND RESULTS: The ACE gene I/D polymorphism was determined in 441 consecutive patients with a first myocardial infarction. There were 69 patients (16%) with the DD genotype, 194 patients (44%) with the ID genotype, and 178 patients (40%) with the II genotype. During a mean follow-up of 9.4 months, there were 49 cardiac deaths (DD, n = 4; ID, n = 26; II, n = 19). The DD genotype was significantly associated with a lower mortality than the other genotypes (p = 0.0363) by Cox regression analysis adjusted for age, sex, site of myocardial infarction, Killip functional class, reperfusion therapy during acute phase, ACE inhibitor use, and beta-blocker use. CONCLUSIONS: In a selected cohort of Japanese patients, the DD genotype was associated with a significantly lower cardiac mortality after a first myocardial infarction.

Female↗
PubMed2001

Idiopathic giant cell granulomatous hypophysitis with hypopituitarism, right abducens nerve paresis and masked diabetes insipidus.

A 38-year-old man presented with headache, fever, and double vision associated with right abducens nerve paresis. He had neither nuchal rigidity nor visual field defect. Laboratory data revealed elevated erythrocyte sedimentation rate (ESR), eosinophilia, and lymphocytic pleocytosis in the cerebrospinal fluid (CSF). Provocation tests of pituitary hormones showed partial hypopituitarism. Magnetic resonance imaging (MRI) revealed swelling of the hypophysis and a mass lesion expanding into the right cavernous sinus. The supplement dose of dexamethasone for hypothalamic hypocortisolism manifested diabetes insipidus. Biopsy, carried out through the transsphenoidal approach, revealed giant cell granuloma. Systemic granulomatous diseases were ruled out, and the lesion was considered to be idiopathic giant cell granulomatous hypophysitis. Right abducens nerve paresis, diabetes insipidus and dysfunction of the anterior lobe were amended by the treatment with prednisolone for 4 months, and findings of the pituitary gland and stalk were normalized. The present case shows that glucocorticoid has an effect on amendment of idiopathic giant cell granulomatous hypophysitis.

Abducens Nerve Diseases↗
PubMed2001

Growth of occult arteriovenous malformation after cerebral hemorrhage demonstrated by serial magnetic resonance imaging--case report.

A 19-year-old male presented with sudden onset of right hemiparesis caused by left cerebral hemorrhage. Cerebral angiography demonstrated no vascular abnormality, and the hematoma was removed surgically. At operation, no abnormal vascular lesion was found in the brain adjoining the hematoma. Two years later, magnetic resonance (MR) imaging demonstrated a few foci of flow voids adjacent to the hematoma cavity. Four years after the hemorrhage, MR imaging showed more extensive flow-void abnormalities that indicated growth of an occult arteriovenous malformation (AVM). Cerebral angiography indicated a definite AVM supplied mainly by branches of the middle cerebral artery. Total resection of this lesion was performed. The histological diagnosis was typical AVM. Immunohistochemistry with vascular endothelial growth factor showed staining in the walls of the abnormal vessels. Serial MR imaging is very useful for the diagnosis and management of occult AVMs.

Adult↗
PubMed2001

A morphological and immunohistochemical study of the ultimobranchial body in the Japanese lizard and the snake.

A morphological and immunohistochemical study of the ultimobranchial body of reptiles Japanese lizard and snake was carried out. The ultimobranchial body of the Japanese lizard was located adjacent to the left arch of the aorta between the trachea and esophagus. It was found as a cluster or group of cells with no capsule. Grimelius' silver impregnation and lead-hematoxylin staining produced positive reactions in some of the clustered cells and follicular cells. The same reaction pattern was observed with anti-calcitonin using the PAP method. The PAP reactions were positive to antiserum against pig calcitonin, but negative to antiserum against synthesized human calcitonin. Furthermore, the PAP reactions were negative to antiserum against tyrosine hydroxylase. The immunofluorescent study of the snake ultimobranchial body revealed that most of the clustered cells and some of the follicular cells were calcitonin-immunoreactive but none was tyrosine hydroxylase-immunoreactive. Certain histological similarities exist between the Japanese lizard ultimobranchial body and snake ultimobranchial body, but the distribution of calcitonin-positive cells were slightly different. In the Japanese lizard, the positive cells were scattered between the foliicles and the number was small. However, most of the cells which formed the cluster in the ultimobranchial body of snake were positive. The findings suggest that the configuration of amino acid in the Japanese lizard calcitonin and snake calcitonin are similar to that of pig calcitonin, and the reptile and the birds is a boundary of the tyrosine hydroxylase existence.

Animals↗
PubMed2001

[Two elderly patients with sarcoidosis and Sjögren's syndrome].

Two elderly patients with sarcoidosis complicated with Sjögren's syndrome are described. Case 1: A 70-year-old woman was admitted due to dry eyes. Histological examination of a minor salivary gland specimen revealed lymphocytic infiltration, which was compatible with Sjögren's syndrome. Because uveitis was demonstrated, transbronchial lung biopsy (TBLB) was performed, to confirm a diagnosis of lung sarcoidosis. Histological examination of TBLB showed non-caseating granulomas compatible with sarcoidosis. Case 2: A 70-year-old woman was admitted due to dyspnea on exercise and blurred vision. Two years previously, Sjögren's syndrome was diagnosed because of a positive Shirmer test and positive SS-A antibody. Result of ophthalmic examination were compatible with uveitis. Histological examination of TBLB showed non-caseating granulomas compatible with sarcoidosis. Certain similarities between sarcoidosis and Sjögren's syndrome in terms of immunological aspects have attracted attention. In the present manuscript, a possible relationship between the two diseases as well as the characteristics of elderly sarcoidosis are discussed.

Aged↗
PubMed2001

Symptomatic solitary xanthogranuloma occupying the cavernous sinus. Case report.

The authors report the first case of a solitary xanthogranuloma of the cavernous sinus without systemic manifestation. A 43-year-old woman experienced decreased visual acuity on the right side in association with papilledema and a visual field defect. She was alert and no other neurological sign was observed. She had no family history of hyperlipoproteinemia and no cutaneous and/or systemic xanthomatous lesions. Skull x-ray films showed an enlarged right superior orbital fissure. Computerized tomography revealed a low-density oval mass 2 x 3 cm in diameter in the right cavernous region that was compressing the right optic nerve in the lateral to medial direction. This mass exhibited isointensity on T1-weighted and mixed-pattern hyperintensity on T2-weighted magnetic resonance images with diffuse contrast enhancement. Cerebral angiography demonstrated fine staining in the margin, originating from the right middle meningeal artery. These neuroimaging findings closely mimicked those associated with trigeminal neuroma. The lesion was partially removed via a right-sided zygomatic approach, and her symptoms improved. Clinical characteristics and histopathological features of this rare case are discussed.

Adult↗