Biomedical subjects

H Kondo

Publications and source records attributed to H Kondo.

At least 451 records · Page 25Linked to original sources

PubMed1996

Re-examination of the carotid body ultrastructure with special attention to intercellular membrane appositions.

Ultrathin sections of the carotid body of adult rats, processed through freeze-substitution after aldehyde-prefixation, showed a substantial number of presumed gap junctions between two adjacent chief cells, between chief and sustentacular cells, and between chief cells and carotid nerve terminals. The junctions showed a very narrow intercellular space of 2 nm and ranged in length from 200 nm to 1 micron. They may form the morphological substrate for electrical coupling between cells, the occurrence of which has been demonstrated by electrophysiology. Further studies using freeze-fracture and immunocytochemistry for connexins are necessary to confirm this possibility. In addition, small tight junctions are present between chief and sustentacular cells, and between adjacent sustentacular cells.

Animals↗

PubMed1996

Changes in element concentrations induced by agonist in pig pancreatic acinar cells.

Changes in electrolytes of pig pancreatic acinar cells following application of gastrin-cholecystokinin (CCK) were investigated using the technique of X-ray microanalysis of hydrated and dehydrated sections of freshly frozen pancreas. After stimulation by CCK (10(-9) M), Na and Cl increased significantly in the cytoplasm [Na, from 10 mmol/kg wet wt. (48 mmol/kg dry wt.) to 19 mmol/kg (95 mmol/kg); Cl, from 22 mmol/kg (105 mmol/kg) to 49 mmol/kg (245 mmol/kg)] as well as in the luminal interspace [Na, from 53 mmol/kg (189 mmol/kg) to 65 mmol/kg (283 mmol/kg); Cl, from 65 mmol/kg (232 mmol/kg) to 102 mmol/kg (443 mmol/kg)]. In the secretory granules Cl increased significantly from 30 mmol/kg (86 mmol/kg) to 67 mmol/kg (203 mmol/kg). K decreased significantly from 120 mmol/kg (571 mmol/kg) to 81 mmol/kg (405 mmol/kg) in the cytoplasm, while both increased from 38 mmol/kg (109 mmol/kg) to 58 mmol/kg (176 mmol/kg) in the granules and from 46 mmol/kg (164 mmol/kg) to 48 mmol/kg (209 mmol/kg) in the luminal interspace. Ca increased significantly in the cytoplasm as well as in the luminal interspace, and decreased significantly in the secretory granules. CCK evoked Ca release from secretory granules in the secretory pole of acinar cells. The values were measured from dehydrated sections, and agreed well with those from hydrated sections. The effect of furosemide, an inhibitor of the Na+-K+-2Cl- co-transporter, on the ion transport of acinar cell was studied. When furosemide (10(-5) M) was added to the external solution, the cytoplasmic Cl and Ca concentrations decreased significantly, while there was a little decrease in Na and K concentrations under the secretory condition. These results indicate that Na+-K+-2Cl- co-transport, and Na+, Cl- and K+ exits into the lumen are involved in the mechanism of ion secretion in pig pancreatic acinar cells.

Animals↗

PubMed1996

The mechanism of Bodian's silver staining: effect of copper ion on silver impregnation.

We studied the effect of the duration (0.5-48 h) of silver impregnation on the intensity of Bodian's silver staining using formalin-fixed, paraffin-embedded sections of a human brain. The silver ion (Ag+) and copper ion (Cu2+) in the silver protein solution were quantified simultaneously for treatments of various durations. Both the intensity of staining and the quantities of Ag+ and Cu2+ were greatly affected by the duration of silver impregnation. While the quantity of Ag+ considerably decreased during the first 4 h of impregnation, that of Cu2+ greatly increased. Only small changes were observed in both ions after 12 h. Neurofibrils or axons, and neurofibrillary tangles (NFTs) were clearly stained after 12-24 and 16-48 h of impregnation, respectively. Strong staining of these components was not observed for other durations of treatment. The amount of metallic copper in silver impregnation also affected both the intensity of staining and the quantities of Ag+ and Cu2+ in the silver protein solution. Ag+ and Cu2+ were also present in the gold trichloride acid solution in which the section was toned. These findings suggest that both Cu2+ derived from metallic copper and silver protein are deposited on sections during silver impregnation, that the amount of Cu2+ may determine the amount of silver protein deposited on the section, and that the reduced (metallic) form of silver and copper on the section may participate in gold toning. Thus, to achieve strong staining of a desired component, it is important to examine the conditions of silver impregnation (i.e. duration and amount of metallic copper). For strong staining of neurofibrils, axons and NFTs, optimal results are obtained by the addition of 5 g of metallic copper foil to 100 ml of 1% silver protein solution, and by 16-24 h of impregnation.

Aged↗

PubMed1996

Enhanced gene expression for phosphatidylinositol 3-kinase in the hypoglossal motoneurons following axonal crush.

We attempted to see whether or not gene expression of phosphatidylinositol 3-kinase (PI 3-kinase) is changeable in the hypoglossal nucleus of rats after hypoglossal nerve crushing by in situ hybridization histochemistry. After unilateral nerve crushing, an apparent enhancement of gene expression for PI 3-kinase was observed in individual neurons of the hypoglossal nucleus at the operated side on the first postoperative day, and it was sustained for 7 postoperative days. Thereafter the expression decreased at the operated side and no significant difference in the expression level was noticed between the operated nucleus and the contralateral, non-operated or sham-operated nucleus on postoperative day 14. The present study suggests that PI 3-kinase contributes to some important roles in morphological changes of mature neurons associated with nerve regeneration.

Animals↗

PubMed1996

Influence of preload, afterload, and contractility on myocardial ultrasonic tissue characterization with integrated backscatter.

Influence of hemodynamic changes in preload, afterload and contractility on myocardial integrated backscatter (IB) was studied in 26 adult mongrel dogs by measuring myocardial IB calibrated with the backscatter from the blood during volume infusion (preload alteration), during aortic constriction (afterload alteration), and during dobutamine or propranolol infusion (contractility alteration). Changes in preload, afterload or contractility did not significantly affect the calibrated myocardial IB either in the septum or in the posterior wall. Changes in preload and afterload did not affect the magnitude of cyclic variation in IB. However, dobutamine produced a significant increase in the magnitude of cyclic variation in IB and propranolol significantly decreased the magnitude of cyclic variation in IB. These data indicated that the calibrated myocardial IB is independent of preload, afterload and contractility, and that the magnitude of cyclic variation in IB is influenced by contractility. We may estimate static (related to histological changes such as fibrosis, edema, necrosis, and so on) and dynamic (related to myocardial contraction such as sarcomere length, muscle fiber orientation, and so on) properties of the myocardium more precisely using myocardial IB calibrated with the backscatter from the blood in addition to the magnitude of cyclic variation in IB.

Adrenergic beta-Agonists↗

PubMed1996

Analysis of transmural trend of myocardial integrated ultrasonic backscatter in patients with old myocardial infarction.

Changes in myocardial integrated backscatter (IB) reflect myocardial viability in patients with myocardial infarction. IB may be obtained separately in the subendocardial and subepicardial layers to establish a transmural trend. The purpose of this study is to examine the possibilities that the measurement of the transmural trend in myocardial IB may provide a new estimate of transmurality of infarction in patients with old myocardial infarction. A calibrated myocardial IB and its transmural trend were measured both in the septum and posterior wall in 21 normal subjects, 24 patients with anteroseptal old myocardial infarction (13 patients with Q-wave myocardial infarction and 11 patients with non-Q-wave myocardial infarction). The transmural trend in myocardial IB was assessed by measuring the acoustic parameter separately in the right and left ventricular halves of the septum, and in the endocardial and epicardial halves of the posterior wall. The magnitude of cyclic variation of IB (a difference between minimum and maximum peaks) was lower, and calibrated myocardial IB (the maximum value of myocardial IB at end diastole calibrated with the power of Doppler signals from the blood along the same ultrasound beam) was higher in patients with anteroseptal old myocardial infarction in the septum, compared with normal subjects. Among patients with myocardial infarction, the difference in these IB parameters between the right and left ventricular halves of the septum was found only in patients with non-Q-wave myocardial infarction. The transmural trend of myocardial IB was likely to reflect the transmurality of myocardial infarction. Therefore, our data give another insight into the assessment of transmural inhomogeneity of myocardial fibrosis or viability in patients with myocardial infarction.

Aged↗

PubMed1996

Heterogeneity of diacylglycerol kinase in terms of molecular structure, biochemical characteristics and gene expression localization in the brain.

Three different cDNA clones for diacylglycerol (DG) kinase were isolated from a rat brain cDNA library and designated DGK-I, DGK-II and DGK-III. These three encode distinct polypeptides with 58% identity to each other and contain EF-hand motifs, cysteine-rich zinc finger-like sequences and putative ATP-binding sites. A high kinase activity is shown in COS cells transfected with either one of the three cDNAs without substrate specificity among DG species, and the kinase activity is Ca-dependent. The activity for DGK-I is recovered dominantly in the soluble fraction of the cell, that for DGK-II in the particulate fraction; and that for DGK-III equally in both of the fractions. The difference in their expression localization is most noticeable: DGK-I is expressed in oligodendrocytes of the brain as well as T-lymphocytes in the thymus and spleen; DGK-II is expressed in neurons of the caudate-putamen, accumbens nucleus and olfactory tubercle; and DGK-III in the cerebellar Purkinje cells and granule cells. The functional significance of the discovery of three DG kinase isozymes is briefly discussed.

Animals↗

PubMed1996

A highly practical synthesis of the sialyl Lewis X pentasaccharide and an investigation of binding to E-, P-, and L-selectins.

A practical synthesis of the sialyl Lewis X (sLex) pentasaccharide, NeuAc alpha 2-3Gal beta 1-4(Fuc alpha 1-3)GlcNAc beta 1-3Gal beta OEt (1), as a potential blocker for E-selectin has been described. The glycosylation of a trisaccharide acceptor, Fuc alpha (1-3)GlcNAc beta (1-3)Gal beta OEt, with a disaccharide donor, NeuAc alpha (2-3)Gal beta SMe, did not yield the desired sLex pentasaccharide 1 at all. However, the glycosylation of a disaccharide acceptor, GlcNAc beta (1-3)Gal beta OEt, with a disaccharide donor, NeuAc alpha (2-3)Gal beta SMe, quantitatively yielded the tetrasaccharide NeuAc alpha (2-3)Gal beta (1-4)GlcNAc beta (1-3)Gal beta OEt. This tetrasaccharide is readily converted to the title compound in a high yield by fucosylation, followed by deprotection. The inhibitory activities of compound 1 toward the binding of the natural ligand (sLex) with the E-, P-, and L-selectins were stronger than those of the sLex tetrasaccharide.

Anti-Inflammatory Agents↗

PubMed1996

Ultrasonic myocardial tissue characterization in patients with dilated cardiomyopathy: value in noninvasive assessment of myocardial fibrosis.

Dilated cardiomyopathy (DCM) is usually diagnosed from the left ventricular functional viewpoint by the detection of dilated ventricular cavity and depressed myocardial contractility. Although histologic analysis of the myocardium no doubt provides clinically important information, it is possible only with microscopic examination of biopsy specimen of the myocardium. The objective of this particular study is to clarify the comparative values of the measures of ultrasonic tissue characterization, that is, calibrated myocardial integrated backscatter (IB) and the magnitude of cyclic variation in IB, with conventional echocardiographic parameters in assessing histologic condition of the myocardium. The magnitude of cyclic variation in IB and myocardial IB at end-diastole calibrate with the power of Doppler signals from the blood were measured in addition to conventional echocardiographic parameters in 14 patients with DCM. Calibrated myocardial IB was higher in patients with more fibrosis in the biopsy specimen of the heart tissue, whereas the magnitude of variation in IB or conventional echocardiographic parameters did not significantly correlate with a histologic estimate of myocardial fibrosis. Calibrated myocardial IB provides information about the myocardial fibrosis that cannot be assessable with conventional echocardiographic parameters. Calibrated myocardial IB and the magnitude of cyclic variation of IB are likely to reflect somewhat different acoustic properties of the myocardium.

Adult↗

PubMed1996

Endothelial dysfunction in the early stage of atherosclerosis precedes appearance of intimal lesions assessable with intravascular ultrasound.

The objective of this study was to clarify whether morphologic evaluation of the in vivo artery with intravascular ultrasound provides as sensitive a marker as endothelial dysfunction or microscopic histologic assessment. Endothelial dysfunction assessed with the changes in the vessel diameter during acetylcholine infusion has been used as a more sensitive marker of atherosclerosis than the angiographic estimates of morphologic structure of the vessel. Recent advent of intravascular ultrasound has provided such high-resolution images of the vessels that morphologic changes in the vessel structure are sensitively and accurately detected. Twenty-two rabbits were divided into three groups: six rabbits fed a cholesterol-rich diet for 2 weeks as the hypercholesterolemia group, eight rabbits fed with the diet for 8 weeks as the atherosclerosis group, and eight rabbits fed a normal diet as the normal group. After evaluating the atherosclerotic lesions by intravascular ultrasound, the cross-sectional area was measured in the baseline and during the infusion of acetylcholine (0.05, 0.5, and 5 micrograms/kg/min) and nitroglycerin (5 micrograms/kg/min). No atherosclerotic lesions were detectable with intravascular ultrasound in any rabbit despite the presence of microscopic intimal lesions in the vessels in the rabbits of the atherosclerosis group. The cross-sectional area increased during acetylcholine infusion in the rabbits of the normal and the hypercholesterolemia groups. In contrast, in the rabbits of the atherosclerosis group, the cross-sectional area did not significantly increase during acetylcholine infusion at the rate of 0.5 microgram/kg/min and even tended to decrease at the rate of 5 micrograms/kg/min (-3.8% +/- 3.7%, P < 0.05 vs the normal group). Dilating responses to nitroglycerin infusion were similar among all three groups. In conclusion, impairment of the endothelium-dependent vasodilating response assessed with intravascular ultrasound in the in vivo vessel precedes the appearance of echographic atherosclerotic findings. Thus intravascular ultrasound, if used in combination with drug intervention to assess endothelial function, would provide even more accurate assessment of the vessels than conventional intravascular ultrasound alone.

Acetylcholine↗

PubMed1996

Myocardial integrated ultrasonic backscatter in patients with old myocardial infarction: comparison with radionuclide evaluation.

The purpose of our study was to clarify whether the abnormalities in integrated backscatter may be used to assess myocardial viability in patients with old myocardial infarction by comparing these integrated backscatter parameters with conventional radionuclide and echocardiographic estimates of myocardial viability. Two myocardial integrated backscatter parameters, the magnitude of cyclic variation in integrated backscatter and the myocardial integrated backscatter calibrated with the power of Doppler signals from the blood along the same ultrasound beam (calibrated myocardial integrated backscatter), were measured in 21 normal persons and 33 patients with old anteroseptal myocardial infarction. Calibrated myocardial integrated backscatter was higher and the magnitude of cyclic variation in integrated backscatter was lower in the infarct septum compared with the septum of normal subjects. Percent thallium uptake, as assessed in scintigraphic images taken at rest or after reinjection, correlated well with the calibrated myocardial integrated backscatter (r = -0.72, p < 0.01) and more weakly but significantly with the magnitude of cyclic variation in integrated backscatter (r = 0.55, p < 0.05) in 16 of 33 patients. The measurement of calibrated myocardial integrated backscatter, in addition to the magnitude of cyclic variation of integrated backscatter, may likely be valuable in the noninvasive assessment of myocardial viability.

Adult↗

PubMed1996

Dual infection with attaching and effacing Escherichia coli and enterotoxigenic Escherichia coli in post-weaning pigs.

Post-weaning diarrhoea in pigs occurred on two farms in Hokkaido, Japan, in 1994. Four piglets aged 35 or 45 days were examined after death. At necropsy, ecchymotic haemorrhages were seen on the mucosal surface of the caecum and colon. Histopathologically, numerous Gram-negative bacilli adhered to the brush border of the small intestines, but the brush border itself was intact. Typical attaching and effacing (AE) lesions were seen in the caecum and colon. Immunohistochemically, the bacilli which adhered to the brush border gave positive results with antisera against serogroup O149 of Escherichia coli; the bacilli which caused the AE lesions, however, belonged to serogroup O45. It was concluded that the disease resulted from dual infection with attaching and effacing E. coli (AEEC) and enterotoxigenic E. coli (ETEC).

Animals↗

PubMed1996

Intestinal adenocarcinoma with neuroendocrine cells in a clouded leopard (Neofelis nebulosa).

Adenocarcinoma of the small intestine was found in a 6-year-old clouded leopard. This tumour was characterized by the presence of goblet and neuroendocrine cells. The latter were labelled positively for either serotonin, somatostatin, neurotensin, gastrin or secretin. These neuroendocrine cells were reduced in number in most of the metastatic lesions, including those of the mesentery, diaphragmatic pleura, lungs, liver and heart, and squamous metaplasia was detected in some metastatic sites.

Adenocarcinoma↗

PubMed1996

Pulmonary resection for metastatic colorectal cancer: experiences with 159 patients.

We reviewed the clinical courses of 159 patients between February 1967 and May 1995 for the purpose of examining the survival of patients who had pulmonary resection for metastatic colorectal cancer. The cumulative survivals at 5 years and 10 years were 40.5% and 27.7%, respectively. Fifteen patients (10%) were alive more than 10 years after the thoracotomy without any evidence of recurrence. The cumulative survival at 5 years for 39 patients who had hepatic metastases before thoracotomy was 33%. There was a statistically significant difference in survival between patients with extrapulmonary metastases and those with only intrapulmonary metastases before thoracotomy. The number of pulmonary metastases and the presence of hilar or mediastinal lymph node metastases affected postthoracotomy survival. There was no significant difference in survival on the basis of sex, age, location of the primary cancer, size of the pulmonary tumors, mode of operation, or disease-free interval. Surgical treatment for pulmonary metastases from colorectal cancer in selected patients, even those who had hepatic metastases before thoracotomy, might improve prognosis.

Adult↗

PubMed1996

Lymph node involvement, recurrence, and prognosis in resected small, peripheral, non-small-cell lung carcinomas: are these carcinomas candidates for video-assisted lobectomy?

To determine the clinicopathologic characteristics of peripheral non-small-cell carcinomas, the cases of 337 patients undergoing major pulmonary resection with complete lymphadenectomy were retrospectively reviewed with regard to lymph node involvement, recurrence, and prognosis. All of the tumors were 3.0 cm or less in diameter and were categorized as T1 (318 patients) or T2 (19). Eighty-eight patients (26.1%) had lymph node involvement: 32 (9.5%) at N1 nodes, 55 (16.3%) at N2 nodes, and 1 (0.3%) at N3 nodes. Although the prevalence of lymph node involvement did not differ significantly with tumor histologic type, it was quite low in squamous cell carcinomas 2.0 cm or less in diameter. Of the 56 N2/3 metastases, 14 (25%) occurred in a "skipping" manner, and all but one had a nonsquamous histologic makeup. Of the 213 patients with a follow-up period of 5 years or more, 59 patients (27.7%) showed cancer recurrence. This occurred at a distant site in 67.8% of the cases. Five-year survival rates based on nodal status were 91.9% (NO), 61.8% (N1), 44.5% (N2), and 0% (N3). Because of the relatively high prevalence of lymph node involvement, complete hilar/mediastinal lymphadenectomy should be routinely done regardless of tumor histologic type and size, as long as patients are at good risk. However, in squamous cell histologic types, mediastinal lymphadenectomy might be dispensable if the tumor is less than 2.0 cm in diameter, or if the hilar node is proved to be tumor-free on pathologic examination of the frozen section during operation. Although video-assisted major pulmonary resection currently has limited application, this new technique may represent a surgical option in resection without complete lymphadenectomy.

Adenocarcinoma↗

PubMed1996

Increased expression of the mRNA for brain- and skin-type but not heart-type fatty acid binding proteins following kainic acid systemic administration in the hippocampal glia of adult rats.

Increased gene expression for two species of cytosolic fatty acid binding proteins (FABPs) after systemic administration of kainic acid in the rat brain was demonstrated by Northern blotting and in situ hybridization histochemical analyses. The expression of brain (B)- and skin (S)- but not heart (H)-FABP mRNAs were markedly elevated in the hippocampus at 48 h after systemic kainate treatment. The elevated expression patterns of B- and S-FABP mRNAs were quite similar to that for glial fibrillary acidic protein in the normal brain, suggesting strongly that the increased expression for B- and S-FABPs occurs in dedifferentiated and proliferated astrocytes in response to kainic acid-induced seizure.

Animals↗

PubMed1996

Spatio-temporally differential expression of genes for three members of fatty acid binding proteins in developing and mature rat brains.

The chronological changes in the gene expression for three species of cytosolic fatty acid-binding proteins (FABPs) in the rat brain were examined by Northern and in situ hybridization analyses. The expression for heart(H)-FABP became evident after birth, with a gradual increase and confined to the gray matter, suggesting that the expression of H-FABP mRNA is neuron-specific in postnatal brain. The expression for brain(B)-FABP was very intense in the ventricular germinal zone, without expression in the cerebellar external granule cell layer, suggesting the dominant expression in the cells of glial lineage. B-FABP mRNA was transiently expressed in perinatal gray as well as white matter and the expression in glial cells persists only in the olfactory nerve fiber layer at the adult stage. On the other hand, the expression for skin type(S)-FABP was evident in the both ventricular germinal zone and cerebellar external granule cell layer, suggesting the expression in cells of neuronal lineage. The expression for S-FABP was evident in the prenatal gray matter and S-FABP mRNA was expressed in glial cells at early postnatal stage, whereafter the expression decreased to, but remained at weak levels in the adult brain. Discrete functions of the three FABPs were suggested in neurons and glia differentially at various developmental stages.

Animals↗

PubMed1996

Role of basal release of nitric oxide in the presence of acute left ventricular dysfunction: comparative study with normal condition.

The basal release of nitric oxide (NO) plays an important role in the regulation of vascular circulation in the presence of acute left ventricular dysfunction. It is not clear, however, whether the role is as important in the presence of acute left ventricular dysfunction as it is in the normal condition. In addition, the effects of flow rate on the role of basal NO have not been clarified in the presence of acute left ventricular dysfunction. This in vivo study was attempted to compare the contribution of the basal release of NO to the regulation of vascular circulation and the effects of a mechanically reduced basal flow rate on the contribution of basally released NO between the normal condition and acute left ventricular dysfunction. In eight anesthetized dogs, the responses of femoral artery blood flow to NG-monomethyl-L-arginine (L-NMMA, 10(-5)M) were observed with and without a reduction in basal flow. The same observation was performed after the production of acute left ventricular dysfunction by coronary microembolization. Without the reduction in basal flow, the L-NMMA-induced decrease in femoral artery flow was significantly larger in acute left ventricular dysfunction than in the normal condition (-40 +/- 12% vs-17 +/- 6%, P < .01). Under the reduction in basal flow, there was no significant change in flow during the infusion of L-NMMA in the normal condition and only a small decrease in acute left ventricular dysfunction. There was no significant difference in the L-NMMA-induced changes in flow between these conditions. The contribution of basally released NO to the regulation of vascular circulation is larger in the presence of acute left ventricular dysfunction than in the normal condition; however, the role of basal NO is reduced with a decrease in basal flow rate.

Acetylcholine↗