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Biomedical subjects

N Yoshimura

Publications and source records attributed to N Yoshimura.

At least 181 records · Page 10Linked to original sources

[Pneumonitis induced by the drug ougon].

We report a case of drug-induced pneumonitis associated with the herbal medications Sho-saiko-to and Ouren-gedoku-to. A 62-year-old man experienced fever and dry cough after using Ouren-gedoku-to for 2 months. He was admitted to our hospital because a subsequent 5-day course of Sho-saiko-to for suspected bronchitis aggravated these symptoms and caused exertional dyspnea. Chest X-ray films revealed a ground-glass appearance in both lower lung fields. Cessation of these medications improved the patient's clinical and X-ray findings. Bronchoalveolar lavage showed an increase in lymphocytes with a decreased CD 4/CD 8 ratio. While drug-induced lymphocyte stimulation tests gave negative results, challenge tests for Ouren-gedoku-to and Sho-saiko-to were both positive. A diagnosis of drug-induced pneumonitis was made. Our findings suggested the involvement of Ougon, the only common ingredient in the two medications.

CD4-CD8 Ratio↗

[Hypereosinophilic syndrome associated with antineutrophil cytoplasmic antibody].

A 68-year-old man was admitted to our hospital with complaints of fever, cough, and shortness of breath. He had several erythematous maculae on the trunk and experienced hypesthesia in his lower extremities. Laboratory data showed marked eosinophilia (20,235/mm3) and enhanced hepatobiliary enzymes. Chest X-ray films and computed tomographic scans revealed diffuse patchy infiltrative changes in the lungs. Histologic findings confirmed eosinophilic infiltration of the skin, liver, and lungs. A diagnosis of hypereosinophilic syndrome (HES) was made in accordance with clinical criteria proposed by Chusid et al. The patient was positive for antineutrophil cytoplasmic antibodies (a marker for vasculitis). This suggested a clinical picture resembling Churg-Strauss syndrome (CSS) despite the lack of bronchial asthma. The findings in this report could contribute to a better understanding of the diversity of HES cases, several of which are considered to represent a continuum of pathologies sharing an etiology similar to that of CSS.

Aged↗

Apoptotic retinal neuronal death by ischemia-reperfusion is executed by two distinct caspase family proteases.

PURPOSE: To evaluate possible roles of caspase-1 and caspase-3 in retinal ischemia-reperfusion injury. METHODS: Retinal ischemia was induced in rats by increasing the intraocular pressure to 110 mm Hg for 60 minutes. Expression of caspase-1 and caspase-3 was studied at the mRNA and protein levels using immunohistochemical staining, western blot analysis, semiquantitative reverse transcription-polymerase chain reaction, and assay of the enzymatic activities. Apoptotic retinal neurons were detected by the TdT-dUTP terminal nick-end labeling (TUNEL) method. To study the roles of the caspases in retinal ischemia-reperfusion injury, an inhibitor of caspase-1, acetyl-tyrosyl-valyl-alanyl-aspart-1-al (Ac-YVAD-CHO; total dose, 10(-7) moles) and that of caspase-3, acetyl-aspartyl-glutamylvalyl-aspart-1-al (Ac-DEVD-CHO; total dose, 10(-7) moles) was injected intravitreally and the number of TUNEL-positive cells was compared with the number in sections not treated with the inhibitors. RESULTS: In the inner nuclear layer (INL), caspase-3-like immunoreactivity was predominantly detected, whereas caspase-1-like immunoreactivity was more predominant in the outer nuclear layer (ONL). Expression of caspase-1 and -3 was upregulated at the protein and gene levels 24 hours after reperfusion. Intravitreal injection of Ac-DEVD-CHO decreased the number of TUNEL-positive cells more significantly in the INL than in the ONL (P < 0.01) at 24 hours, whereas, intravitreal injection of Ac-YVAD-CHO was more effective in decreasing the number in the ONL (P < 0.05). CONCLUSIONS: These findings suggest a possibility that cell-type-specific activation of caspases takes place in retinal ischemia-reperfusion injury, and such caspase may induce retinal neuronal cell death.

Animals↗

BDNF diminishes caspase-2 but not c-Jun immunoreactivity of neurons in retinal ganglion cell layer after transient ischemia.

PURPOSE: Retinal ischemia-reperfusion injury induces apoptosis of retinal neurons. The purpose of this study was to examine the association of c-Jun, caspase-1, -2, and -3 immunoreactivities and neuronal apoptosis in the retinal ganglion cell layer (GCL) and to study the effects of intravitreal brain-derived neurotrophic factor (BDNF) on the expression of these gene products in a rat model of retinal ischemia-reperfusion injury. METHODS: After 60 minutes of ischemia, eyes were enucleated after 3, 6, 12, 24, and 168 hours of reperfusion. The numbers of c-Jun-, caspase-1-, caspase-2-, caspase-3, and TdT-dUTP terminal nick-end labeling (TUNEL)-positive cells in the GCL were counted. Recombinant human BDNF (5 microg) or vehicle was injected intravitreally immediately after reperfusion. At 6, 24, and 168 hours, the numbers of immunoreactive cells in BDNF- and vehicle-treated groups were compared. RESULTS: Expression of c-Jun and caspase-2 was found in dying cells in flat-mounted retinas. The numbers of caspase-1- and caspase-3-positive cells were fewer than c-Jun- or caspase-2-positive cells. Cell death in the retinal GCL was suppressed by an intravitreal injection of BDNF. The numbers of TUNEL- and caspase-2-positive cells were lower in the BDNF-treated group at 6 hours after reperfusion (P<0.01). The number of c-Jun-positive cells in the treated retinas was not altered by the treatment. CONCLUSIONS: Expression of c-Jun and caspase-2 is associated with neuronal cell apoptosis in the GCL. Suppression of caspase-2 expression may explain the neuroprotective effects of BDNF.

Animals↗

[New monitoring strategies during shock].

Disturbances in tissue perfusion and oxygenation are known to occur during shock. To treat shock properly, it is necessary to have a good understanding of its pathophysiological characteristics. By monitoring cardiac output and oxygen delivery, we can assess the systemic oxygen transport to the tissues, while mixed venous oxygen saturation provides an index of the systemic oxygen balance between oxygen delivery and consumption. However, because a redistribution of blood volume and flow occurs in shock, the use of systemic monitoring alone does not allow an assessment of regional oxygenation in the various organs. Monitoring of hepatic and jugular venous oxygen saturation enables us to assess the adequacy of regional tissue oxygenation in the liver and brain, respectively, while monitoring intramucosal pH (pHi) is useful not only to assess regional oxygenation in the splanchnic organs, but also to predict complications and to evaluate the clinical outcome. The use of near-infrared spectroscopy may allow simultaneous, noninvasive monitoring of regional tissue oxygenation and energy levels. There exists a wide variety of viable options for the monitoring of shock, both systemically and regionally. This increases the chances of successful treatment.

Brain↗

Roles of constitutive nitric oxide synthase in postischemic rat retina.

PURPOSE: Nitric oxide is a reactive species that could be protective or destructive to the retina depending on the stage of the evolving ischemic process. This study was conducted to obtain a better understanding of the roles of constitutive nitric oxide synthase (cNOS) during reperfusion after ischemia in rat retina. METHODS: Retinal ischemia was induced for 60 minutes in Sprague-Dawley rats by ligating the optic nerve. Gene expression for endothelial and neuronal nitric oxide synthases (eNOS and nNOS) was studied by reverse transcription-polymerase chain reaction (RT-PCR). To inhibit cNOS, NG-nitro-L-arginine (L-NNA) was injected intraperitoneally four times (every 6 hours) beginning 2 hours after reperfusion, for a total dose of 80 mg/kg. Retinal damage was assessed by the rate of a- and b-wave recovery on electroretinograms and by the thickness of the retinal layers. Retinal circulation and vessel diameter were evaluated by the dye-dilution technique. RESULTS: After ischemia ended, eNOS mRNA initially decreased until 6 hours, then increased to a peak at 12 hours, and decreased progressively beyond 24 hours until the final measurement at 96 hours of reperfusion. nNOS mRNA decreased to nearly undetectable levels during the same measurement periods. L-NNA treatment enhanced reduction of a- and b-wave amplitudes and increased thinning of the inner retina in postischemic eyes. Retinal mean circulation time was markedly prolonged in L-NNA-treated postischemic eyes. Arterial mean transit times were 2.1-fold and 4.5-fold longer in L-NNA-treated postischemic eyes than in L-NNA-treated nonischemic eyes and in D-NNA-treated postischemic eyes, respectively. CONCLUSIONS: This study shows that postischemic inhibition of NOS worsens retinal damage after ischemia-reperfusion and alters postischemic retinal circulation. Nitric oxide may play an important role in protecting the retina from ischemic injury, possibly by preventing postischemic hypoperfusion.

Animals↗

Suppression of laser-induced choroidal neovascularization by oral tranilast in the rat.

PURPOSE: To determine whether tranilast administered to pigmented rats inhibits formation of choroidal neovascularization induced by diode-laser photocoagulation. METHODS: Female Brown Norway rats were used. On day 0, choroidal neovascularization was induced by diode-laser photocoagulation, using a setting of 75 microm spot size, 0.1 second's duration, and 100 mW intensity. Tranilast (200 or 600 mg/kg per day) was administered orally twice daily for 14 days. Indomethacin (1 and 5 mg/kg per day) was administered orally once a day for 14 days. Choroidal neovascularization was evaluated on days 7 and 14 by fundus photography and fluorescein angiography. Late-phase fluorescein angiography was scored according to four grades. The animals were killed on day 14, and the lesions were evaluated histologically. RESULTS: In the vehicle-treated group, 34 of 35 burns (97%) showed fluorescein staining and late leakage on day 14. Choroidal neovascularization was identified by light microscopy in all the lesions that showed fluorescein staining and late leakage. The score of fluorescein staining was reduced in rats given 200 mg/kg per day or 600 mg/kg per day (P < 0.01) of tranilast. The thickness of the laser-induced lesions was reduced in a dose-dependent manner by tranilast, a significant difference was observed with 600 mg/kg per day (P < 0.05). Oral indomethacin treatment did not reduce fluorescein staining on day 14. CONCLUSIONS: Tranilast inhibits the development of choroidal neovascularization in this experimental model.

Administration, Oral↗

A possible role for p16INK4 in neuronal cell death after retinal ischemia-reperfusion injury.

PURPOSE: To study whether cell type-specific death occurs in retinal ischemia-reperfusion injury and the possible roles of p16INK4 in the determination of cell death. METHODS: Retinal ischemia-reperfusion injury was induced in rats by a ligation method. After 1 hour of ischemia and a time of reperfusion that varied, rat eyes were enucleated. Cell death in the retina was studied by the TdT-dUTP terminal nick-end labeling method and propidium iodide (PI) staining. Electron microscopic observation of the retina was also performed. Immunohistochemical studies using antibodies against syntaxin and calbindin were performed to detect amacrine cells and horizontal cells, respectively, and immunohistochemical studies using an antibody against p16INK4 were performed to study whether this cell cycle-related protein was expressed in dying cells. RESULTS: Most of the calbindin-positive horizontal cells in the outer aspect of the inner nuclear layer (INL) showed morphologic features of necrosis. In contrast, syntaxin-positive amacrine cells in the inner aspect of the INL showed features of apoptosis. Of 320 calbindin-positive horizontal cells, only 11 (3.4%) showed positive PI staining. Those calbindin-positive, horizontal cells were p16INK4 positive. In contrast, 746 of 910 (82.0%) syntaxin-positive amacrine cells showed condensed PI staining, and none were p16INK4 positive. CONCLUSIONS: Expression of p16INK4 may regulate the fate of retinal neurons in ischemia-reperfusion injury, and cell type-specific death thus occurs in the retina after such injury.

Animals↗

Expression of tissue factor in hepatic ischemic-reperfusion injury of the rat.

BACKGROUND: Tissue factor (TF) is a membranous protein normally present on the surface of the fibroblasts and smooth muscle cells of vessels. TF is an initiation factor for blood coagulation, and its expression is induced on macrophages and endothelial cells during the inflammatory or immune response. We studied the significance of TF expression in warm ischemic-reperfusion injury of the liver using a rat model. METHODS: Following laparotomy of Lewis rats, the branches of the hepatic artery and portal vein leading to the median, left, and caudate lobes of the liver were clamped for 2 hr. The liver was reperfused after 120 min of ischemia. Rats were killed at 0, 1, 3, 5, 8, and 12 hr after reperfusion, and liver tissues were harvested. TF activity was measured by the chromophilic substrate S-2222. TF expression was studied by immunohistochemical staining with the monoclonal antibody HTF-K108. RESULTS: TF activity in the blood showed a peak at 3 hr after reperfusion (8.9+/-0.5 U/L), then decreased and returned to the normal level by 12 hr (0.9+/-0.3 U/L). TF activity in ischemic liver tissue increased gradually over 12 hr after reperfusion (1223+/-275 U/g dry weight before ischemia and 2545+/-284 U/g weight at 12 hr after reperfusion). Histologically spotty necroses were observed in the liver tissue 5 hr after reperfusion. The necrotic area extended and encompassed almost all of the ischemic liver by 12 hr after reperfusion. Histochemically, TF staining was negative on the hepatocytes and slightly positive on sinusoid cells of the normal liver. On the other hand, TF was strongly stained, especially on the hypertrophic monocytic cells accumulating at the site of the necrosis, but staining was not evident on the necrotic hepatocytes. A slight degree of TF staining was observed on the alveolar epithelium of the lung, irrespective of liver ischemia and reperfusion. CONCLUSION: These results demonstrate that TF plays an important role in the development of the hepatic ischemic-reperfusion injury, and the subsequent microcirculatory incompetence might cause the formation of microthrombus and the development of necrosis.

Alanine Transaminase↗

The expression and localization of fibroblast growth factor-1 (FGF-1) and FGF receptor-1 (FGFR-1) in human breast cancer.

Fibroblast growth factor-1 (FGF-1) is an inducer of angiogenesis, the growth of new blood vessels. The expression and localization of FGF-1 (acidic FGF) and FGF receptor (FGFR)-1 in mammary tissues from patients with breast cancer was investigated using Western blot analysis and immunohistochemistry. The affinity-purified FGF-1 antibody which did not have cross-reactivity to FGF-2 (basic FGF) was used in this study. Western blot analysis demonstrated the presence of FGF-1 protein in all of the samples from breast cancer, but not benign tumors such as mastopathy and fibroadenoma. To assess the localization of FGF-1 in cancer tissues, immunostaining with specific antibody was performed. All samples from breast cancer displayed significantly intense staining with FGF-1 antibody. The extent and intensity of immunoreactive FGF-1 polypeptides in cancer cells was statistically much greater than those of cells from fibroadenoma or mastopathy. Control immunostaining with normal rabbit serum or anti-FGF-1 antibody adsorbed with the recombinant FGF-1 polypeptide was completely negative. In contrast to FGF-1, Western blot analysis demonstrated the presence of FGFR-1 protein in all of the samples from breast cancer and benign tumors. By immunohistochemical analysis, the enhanced expression of FGFR-1 was observed in breast cancer cells. Benign tumor cells or interstitial cells displayed a faint expression of FGFR-1. These results demonstrated that breast cancer cells not only generated FGF-1, but also expressed FGFR-1, and FGF-1 might play a role in the proliferation of breast cancer cells not only by paracrine but also by autocrine mechanism.

Adult↗

Ocular hypotension induced by intravitreally injected C-type natriuretic peptide.

The purpose of the study is to determine if intravitreal injection of c-type natriuretic peptide (CNP) affects intraocular pressure (IOP), aqueous humor dynamics and guanosine 3',5'-cyclic monophosphate (cGMP) concentration in the aqueous humor of the rabbit eye. Also we investigated whether CNP-like immunoreactivities (CNP-LI) were present in porcine aqueous humor and whether CNP-LI were detected in rabbit and porcine ciliary body. The IOP was measured after intravitreal injection of 2 pmol approximately 20 nmol CNP into rabbit eyes. Aqueous humor dynamics (aqueous humor flow, outflow facility, and uveoscleral outflow) and cGMP concentration in the aqueous humor were determined at approximately 6 hr after CNP injection. The CNP concentration in aqueous was measured by radioimmunoassay in porcine eye, and CNP-LI were detected with a monoclonal antibody in porcine and rabbit eyes. Intravitreally injected CNP caused IOP reduction in a dose-dependent manner (P<0.0001) and the maximum effect was observed at 4 approximately 6 hr. CNP increased total outflow facility by approximately 35%, but did not affect aqueous humor flow or uveoscleral outflow. The cGMP concentration in the aqueous of CNP-treated eyes was about 4- to 14-fold higher than that in the contralateral untreated eyes. CNP concentration in aqueous was about 2-fold higher than that in plasma, and CNP-LI were found in non-pigmented epithelium of the ciliary body of both rabbit and porcine eyes. CNP may play an important role in the regulation of IOP.

Animals↗

Dynamic changes in intracapillary hemoglobin oxygenation in human skin following various temperature changes.

To evaluate microvascular regulation in human skin, changes in intracapillary hemoglobin oxygen saturation (HbO2) were studied in human finger skin following an abrupt change in local ambient temperature. In the first series of experiments, we assessed the heterogeneity of HbO2 in the skin by using a 2-D scanning system and a rapid micro-lightguide spectrophotometer at each of two near-normal skin temperatures. The data showed that heterogeneous oxygenation exists in human skin even at near-normal temperatures (although the pattern is different at different skin temperatures). In a second series of experiments, the performance of the microcirculation of the skin was continuously examined in a selected area with initially different oxygenation levels during an abrupt change in local ambient temperature (5, 15, 25, 35, and 45 degrees C). At very low (5 degrees C) or very high (45 degrees C) temperatures, oxygenation in tissues within the low HbO2 area increased greatly, but there was no such change within the high HbO2 area. Our data indicate that different types of capillary supply units exist in human skin (indicated by the initially different oxygenation levels). These different capillary supply units may operate to produce a local redistribution of flow between the various capillary supply units. This effect may be initiated by heat sensors and oxygen sensors when temperature of the skin is varied.

Adult↗

Successful surgical treatment of an Edwards type IIIB right aortic arch aneurysm: report of a case.

A true aneurysm of the right aortic arch which accompanies various branching characteristics is very rare. We report herein the successful surgical treatment of an elderly patient found to have an Edwards type IIIB right aortic arch aneurysm encircling and compressing the trachea. The complete right aortic arch and right subclavian artery were reconstructed through the inside of the aneurysm using selective cerebral perfusion. The patient recovered well, with no residual neurologic deficit and with resolution of the dyspnoic attacks he had suffered preoperatively.

Aortic Aneurysm, Thoracic↗

[Pulmonary artery sling with tracheal stenosis--primary repair in infancy].

Between 1984 and 1996 five infants underwent surgical repair of pulmonary artery sling associated with severe congenital tracheal stenosis. All infants had symptoms of severe respiratory distress and three of them required ventilator support preoperatively ages ranged from 2 to 11 months (mean age 6 months). Complete tracheal rings were present in all patients as an associated lesion and right upper lobe tracheal bronchus in 3 patients. The length of tracheal stenosis ranged from 18 to 45 mm (median 40 mm). Three had associated intracardiac anomalies (Scimitar syndrome (1), VSD (1), double-outlet right ventricle with VSD (1), double-outlet right ventricle with pulmonary hypertension (1)). Surgical intervention was carried out through a right thoracotomy (1) or median sternotomy (4). Cardiopulmonary bypass (CPB) was used in 3 patients and extracorporeal membrane oxgenator (ECMO). In 1. All infants had reimplantation of the left pulmonary artery into the main pulmonary artery left anterior to the trachea. Four patients underwent simultaneous tracheoplasty using costal cartilage grafts and one had complete resection of obstructed trachea between the right upper lobe tracheal bronchus and carina. The length of resected trachea was about 30% of the entire length of the trachea. Three infants underwent simultaneous intracardiac repair. There was no hospital death. All were weaned from ventilatory support and extubated on 1 to 16 months (mean 4, 5 months) postoperatively. AS an additional procedure, aortopexy, removal of granulation tissue or balloon dilatation of the trachea were carried out in one patient each following tracheoplasty using cartilage grafts. There was one late death at 1 year postoperatively. Three of 4 survivors are doing well with no stridor. We adonostridor. We adovocate 1) early aggressive primary repair of pulmonary artery sling with tracheal stenosis, 2) concomitant repair of tracheal lesion and intracardiac anomalies whenever possible, 3) application of CPB or ECMO to avoid cumbersome intubation technique, and 4) utmost effort to perform tracheal resection and end-to-end anastomosis.

Anastomosis, Surgical↗

Determinants of bone loss in a rural Japanese community: the Taiji Study.

The objective of this study was to assess the rate of bone loss and characterize its determinants, among the inhabitants of Taiji, a rural Japanese community. A cohort of 2261 inhabitants aged 40-79 years was established using resident registration in 1992. Fifty men and 50 women in each of four age strata between 40 and 79 years were randomly selected and completed a self-administered risk factor questionnaire. Baseline bone density of lumbar spine and proximal femur was measured by dual-energy X-ray absorptiometry in 1993. BMD was measured again on the same participants in 1996. The rates of change of lumbar spine BMD in men in their 40s, 50s, 60s and 70s were 0.20%, 0.34%, 0.43% and 0.28% respectively. Rates in women were -0.35%, -1.02%, -0.10% and -0.20% respectively. At the femoral neck, rates of change in BMD among men in their 40s, 50s, 60s and 70s were 0.09%, -0.07%, 0.34% and 0.31% respectively. Femoral neck rates of change among women were -0.55%, 0.02%, 0.49% and -0.25% respectively. The rate of change of lumbar spine BMD was -0.24% in premenopausal women with regular periods, -1.99% in premenopausal women with irregular periods and -0.33% in postmenopausal women. Anthropometric measurements at baseline were also related significantly to change in bone density. Baseline weight and height were statistically significant predictors of bone loss rate. These data provide estimates of the rate of bone loss among Japanese men and women aged 40-79 years. They suggest that body build and menstrual function in women are important determinants of bone loss.

Adult↗

Comparative study of event-related potentials and positron emission tomography activation during a paired-associate memory paradigm.

Event-related potentials (ERP) and regional cerebral blood flow (rCBF) activation using 15O-labeled water associated with retrieval and retention of episodic memory were studied during a visual paired-association task with delayed response in eight healthy subjects. In both studies, the subjects memorized four pairs of figures during the learning period. They were presented with each cue (S1) and asked to judge whether the following figure (S2) formed one of the memorized pairs. In an attempt to identify brain activity related to memory function, a choice reaction task with delay was used as a behavioral control. The ERP study showed a posterior positive component in the difference waveform, which was obtained by subtracting responses in the choice reaction task from those in the paired association task, between 300 and 850 ms after S1 presentation. It was maximal at the parietal midline electrode and distributed predominantly over the left posterior quadrant of the scalp. The rCBF activation study showed a greater increase in rCBF in the right dorsolateral prefrontal cortex (Brodmann's area 46), left inferior frontal cortex (Brodmann's area 44/45), left thalamus, and bilateral cerebellar hemisphere during the paired association task as compared to the choice reaction task, which suggests a possible involvement of cerebello-thalamo-cortical circuit in the memory processing. Additionally, it is suggested that the scalp distribution of the ERP component may not necessarily represent regional cortical activation below the electrodes where such a component is observed and could indirectly represent activation in remote areas such as subcortical regions. It seems that ERP and rCBF activation may provide information about different aspects of higher brain function.

Adolescent↗

Development of extrahepatic arterial blood supply to the liver during hepatic arterial infusion chemotherapy.

The aim of this study was to evaluate the correlation of development of the collateral circulation to the liver during hepatic arterial infusion chemotherapy (HAIC) with the presence of hepatic tumours adjacent to the hepatic surface, and with pretreatment occlusion of aberrant hepatic arteries. In 102 patients with unresectable malignant hepatic tumours treated with HAIC using an implantable port system, development of collaterals to the liver was assessed with CT arteriography using the implantable port and pre- and postoperative angiography. Aberrant hepatic arteries, if present, were occluded prior to treatment for hepatic arterial redistribution. Collaterals to the liver were seen in 29 patients, who had 35 areas with collateral perfusion: 22 areas were in the right posterosuperior area, 6 in the left peripheral area and 7 in the right or left lobar area. Collaterals were revealed more frequently in patients with hepatic tumours adjacent to the hepatic surface than in those without hepatic tumours in peripheral areas in the liver (p < 0.0001). In addition, collaterals developed more frequently in patients with an aberrant hepatic arterial anatomy compared with those with conventional anatomy (p = 0.0007). Our results indicated that patients with hepatic tumours adjacent to the hepatic surface and with pretreatment occlusion of aberrant hepatic arteries had the potential to develop collaterals to the liver during HAIC.

Adult↗