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Biomedical subjects

Shigeru Kohno

Publications and source records attributed to Shigeru Kohno.

At least 271 records · Page 15Linked to original sources

Evaluation of newly developed oxygen meters with multi-channels and disposable oxygen electrode sensors for antimicrobial susceptibility testing.

The objective of this study was to investigate the applicability of new oxygen meters with multi-channels and disposable oxygen electrode sensors (DOX-96) on the antimicrobial susceptibility testing of clinical bacterial isolates. The oxygen amount in the wells of 96-well plates was converted into current through electrodes. Bacterial inoculation decreased the oxygen amount in the wells because viable bacteria consume the oxygen. On the other hand, a failure of bacteria to consume oxygen was observed in the presence of potent antimicrobial agents, representing a serious arrest of bacterial metabolism usually leading to stasis or death. Based on these results, the minimum inhibitory concentration was determined by DOX-96 (MICdox). The MICdox showed good agreement with MIC measured by the standard broth microdilution method (98.2%). DOX-96 was also useful for turbid samples such as Mueller-Hinton broth containing 0.1% lipid emulsion. The MICdox in turbid samples showed good agreement with those in clear samples (100.0%). These results indicate that the newly developed DOX-96 is very useful in antimicrobial susceptibility testing even in turbid clinical samples such as colloidal products and turbid biological components.

Anti-Bacterial Agents↗

Relationship between ECG findings and pulmonary artery pressure in patients with acute massive pulmonary thromboembolism.

Pulmonary thromboembolism (PTE) is associated with various electrocardiogram (ECG) abnormalities, but the utility of evaluating the severity of PTE based on ECG abnormalities alone has not been investigated in Japanese patients previously. The purpose of this study was to examine the relationship between ECG abnormalities and the mean pulmonary artery pressure (MPAP) in patients with acute massive PTE (AMPTE). ECG examination of 21 patients, who were diagnosed with AMPTE by pulmonary arteriography, found that S(1)Q(3)T (3) was the most frequently observed abnormality (in 67% of the patients), followed by negative T (62%), clockwise rotation (57%), and ST elevation (48%). When these patients were divided into 2 groups based on the level of MPAP, 8 of the 11 ECG findings, which were associated with PTE in a previous report, were more frequently observed in Group H (MPAP >/=40 mmHg) than in Group L (MPAP <40 mmHg). MPAP correlated significantly with the total number of ECG abnormalities (r=0.82, p<0.001). In particular, at least 5 ECG abnormalities were noted in patients with MPAP >/=45 mmHg. These results suggested that the total number of ECG abnormalities in patients with AMPTE can be used to evaluate the severity of APTE, including PAP level.

Acute Disease↗

Role of autonomic nervous dysfunction in electrocardio-graphic abnormalities and cardiac injury in patients with acute subarachnoid hemorrhage.

Electrocardiographic abnormalities, cardiac injury, and autonomic nervous function were investigated in patients with acute-phase subarachnoid hemorrhage (SAH) (42 patients with SAH related to ruptured aneurysm and 42 control subjects). Electrocardiogram and Holter electrocardiogram for spectral analysis of heart rate variability (HRV) were recorded. Concentrations of cardiogenic enzymes (ie, creatine kinase-myocardial fraction [CK-MB], myosin light chain I, and troponin T), plasma concentrations of catecholamine (ie, noradrenaline, adrenaline, 3-methoxy-4-hydroxy-phenylethylene glycol [MHPG]) and HRV were compared in the acute and chronic phase of SAH, and with the values in the controls subjects. As previously reported, patients with acute SAH exhibited electrocardiographic (ECG) abnormalities and increased concentrations of both cardiogenic enzymes and plasma catecholamines, suggesting that acceleration of sympathetic activity is involved. However, HRV analysis showed enhanced parasympathetic activity, probably associated with increased intracranial pressure after the onset of SAH, which may be explained by accentuated antagonism, negative feedback of noradrenaline to the center, and reduction of sympathetic activity after reaching a peak level. The results suggest that not only sympathetic activity but also vagal activity is enhanced during the acute phase of SAH, thus contributing to the ECG abnormalities and the onset of cardiac injury.

Acute Disease↗

Expression of heat shock protein (Hsp) 70 and Hsp 40 in colorectal cancer.

Heat shock protein (Hsp) 70 and Hsp 40 are stress proteins that cooperate as chaperones in mammalian cells. The present study was designed to determine the expression levels of Hsp 70 and Hsp 40 in colorectal cancer by immunohistochemistry and Western blot analysis. Among 50 colorectal cancer tissues studied, 80% and 14% of tumors showed specific immunoreactivity to Hsp 70 and Hsp 40, respectively. Hsp 70 and Hsp 40 were overexpressed in cancer tissue samples compared with normal tissues, on both analytic sets. However, there were no significant correlations between their expression and various clinicopathological parameters of colorectal cancer. Hsp 70 and Hsp 40 may be tumor markers for colorectal cancer.

Adult↗

[Clinical and mycological features of cryptococcosis].

Cryptococcosis is the third most common deep mycosis in Japan. Cryptococcus neoformans is known to grow in pyres of pigeon feces. Chicken feces in Thailand were tested for whether C. neoformans could be isolated, because there is considerable prevalence of cryptococcal meningitis in patients with HIV in that country. We isolated C. neoformans from chicken feces in as many as at 70 % of the villages tested. Chicken as well as pigeon feces were believed to be an origin of infection. We have studied the relation between in vitro virulence and thickness of polysaccharide capsules. Strains with thicker capsules such as YC-11 or YC-5 showed more resistance to macrophage phagocytosis than strains with thinner capsules like YC-27 or YC-13. This finding was consistent with the cytokine dynamic state in mice cryptococcosis. Th1 was dominant in infections with thinner capsule strains, although Th2 was relatively dominant in those with thick capsules. The clinical features of 104 cases with pulmonary cryptococcosis were summarized. Radiological findings of pulmonary cryptococcosis varied depending on the time course of the disease and on immunological status. There were no specific symptoms and signs except for positive glucronoxylomannan. Those in azole class were the most commonly prescribed antifungals. New generation antifungals voriconazole and intravenous itraconazole showed potent clinical efficacy in pulmonary cryptococcosis.

Animals↗

[Azole resistance in Candida spp].

The emergence of azole-resistant Candida spp. is a significant problem after long-term treatment of recurrent oropharyngeal candidiasis in HIV-infected patients. Several mechanisms can cause this resistance. An important mechanism of azole resistance is reduced intracellular accumulation of the drug. Among the multidrug efflux transporters, ABC transporters and the major facilitator superfamily are reported to cause the resistance. Erg11p, sterol C14 alfa-demethylase, is a target of azole derivatives. It was reported that ERG11 over-expression had only a modest effect on the development of azole resistance. However, mutations in the ERG11 gene can cause the resistance, probably by reducing binding of azole to the target enzyme. We sequenced the ERG11 gene in a high-level azole resistant C. albicans strain, Darlington, and found that two amino acid substitutions, Y132H and I471T, had been encoded in the Darlington ERG11 gene. To assess the significance of these substitutions, we replaced one of the two copies of ERG11 gene in anazole-susceptible strain of C. albicans with a copy of the Darlington ERG11 and this resulted in a modest increase in azole resistance. Furthermore, to estimate the effect of Y132H and I471T individually, ERG11 genes with either or both mutations were expressed in S. cerevisiae. The I471T substitution, not previously described, conferred azole resistance when overexpressed alone and increased this resistance when added to the Y132H substitution. Alterations in the sterol biosynthetic pathway are another resistance mechanism. Inhibition of 14 alfa-demethylase by azole results not only in ergosterol depletion but also in accumulation of methylated sterol 14 alfa-methylergosta-8, 22(28)-dien-3 beta, 6 alfa-diol. We deleted the ERG3 gene, which encodes a sterol 5, 6-desaturase, in C. albicans, and the deletion resulted in reduced susceptibility of the mutant to azoles.Sterol analysis revealed that erg3 mutant lost both ergosterol and diol when cultured with fluconazole.

Antifungal Agents↗

Expression of mucosal addressin cell adhesion molecule 1 on vascular endothelium of gastric mucosa in patients with nodular gastritis.

AIM: The interaction of mucosal addressin cell adhesion molecule 1 (MAdCAM-1) with integrin alpha4beta7 mediates lymphocyte recruitment into mucosa-associated lymphoid tissue (MALT). Nodular gastritis is characterized by a unique military pattern on endoscopy representing increased numbers of lymphoid follicles with germinal center, strongly associated with H pylori infection. The purpose of this study was to address the implication of the MAdCAM-1/integrin beta7 pathway in NG. METHODS: We studied 17 patients with NG and H pylori infection and 19 H pylori-positive and 14 H pylori-negative controls. A biopsy sample was taken from the antrum and snap-frozen for immunohistochemical analysis of MAdCAM-1 and integrin beta7. In simultaneous viewing of serial sections, the percentage of MAdCAM-1-positive to von Willebrand factor-positive vessels was calculated. We also performed immunostaining with anti-CD20, CD4, CD8 and CD68 antibodies to determine the lymphocyte subsets co-expressing integrin beta7. RESULTS: Vascular endothelial MAdCAM-1 expression was more enhanced in gastric mucosa with than without H pylori infection. Of note, the percentages of MAdCAM-1-positive vessels were significantly higher in the lamina propria of NG patients than in H pylori-positive controls. Strong expression of MAdCAM-1 was identified adjacent to lymphoid follicles and dense lymphoid aggregates. Integrin beta7-expressing mononuclear cells, mainly composed of CD20 and CD4 lymphocytes, were associated with vessels lined with MAdCAM-1-expressing endothelium. CONCLUSION: Our results suggest that the MAdCAM-1/integrin alpha4beta7 homing system may participate in gastric inflammation in response to H pylori-infection and contributes to MALT formation, typically leading to the development of NG.

Base Sequence↗

Impact of endoscopically minimal involvement on IL-8 mRNA expression in esophageal mucosa of patients with non-erosive reflux disease.

AIM: Little has been known about the pathogenesis of non-erosive reflux disease (NERD). Recent studies have implicated interleukin 8 (IL-8) in the development and progression of gastroesophogeal reflux disease (GERD). The purpose of this study was to determine IL-8 RNA expression levels in NERD patients with or without subtle mucosal changes. METHODS: We studied 26 patients with NERD and 13 asymptomatic controls. Biopsy sample was taken from the esophagus 3 cm above the gastroesophageal junction and snap frozen for measurement of IL-8 mRNA levels by real-time quantitative polymerase chain reaction (PCR). We also examined mRNA expression of IL-8 receptors, CXCR-1 and -2 by reverse transcriptase PCR. The patients were endoscopically classified into grade M (mucosal color changes without visible mucosal break) and N (neither minimal involvement nor mucosal break) of the modified Los Angeles classification. RESULTS: The relative IL-8 mRNA expression levels were significantly higher in esophageal mucosa of NERD patients than those in esophageal mucosa of the controls. There was a significant difference in IL-8 mRNA levels between grades M and N. The CXCR-1 and -2 mRNAs were constitutively expressed in esophageal mucosa. CONCLUSION: Our results suggest that high IL-8 levels in esophageal mucosa may be involved in the pathogenesis of NERD through interaction with its receptors. NERD seems to be composed of a heterogeneous population in terms of not only endoscopically minimal involvement but also immune and inflammatory processes.

Adult↗

Pedunculated rectal carcinoid removed by endoscopic mucosal resection: a case report.

Carcinoid tumors generally appear as yellow/gray or tan submucosal nodules. We experienced a case of pedunculated rectal carcinoid showing a mushroom-like appearance. The case was a forty years old woman who was admitted to our hospital due to rectal bleeding. Colonoscopy revealed a pedunculated polyp presenting a mushroom-shaped appearance measuring 13 mm in diameter in the rectum. The histological diagnosis of specimens obtained by biopsy was adenocarcinoma and transanal ultrasonography revealed the tumor localization within the submucosal layer in the rectum. Endoscopic mucosal resection (EMR) was performed. Histopathological examination established the diagnosis of carcinoid tumor in the rectum. Frequencies of the pedunculated type in rectal carcinoids were reported to be 2.4% to 7.1% in the literature. Because of its rarity, pedunculated configuration may confuse the endoscopic diagnosis of carcinoids. Treatment for carcinoids of 1 to 1.5 cm in size remains controversial. Although such tumors are technically respectable by EMR, careful attention must be paid in dealing with these tumors because there may be unexpected behaviors of the tumors.

Adult↗

[A case of pulmonary involvement of malignant lymphoma with diffuse ground-glass opacity in chest CT].

A chest CT of an 82-year-old woman suffering from general fatigue revealed ground-glass opacities in both lower lung fields. Antibiotics were administered, but the ground-glass opacities developed into air-space consolidation with air-bronchogram. Hematuria was observed and abdominal CT showed multiple retroperitoneal masses, suggesting malignant lymphoma. The case was diagnosed histopathologically as malignant lymphoma (non-Hodgkins) of the diffuse, medium-sized B cell type on the basis of a right inguinal lymph node biopsy. Autopsy results suggested that the malignant lymphoma may have developed from the left adrenal gland. In the lungs, lymphoma cells infiltrated mainly into the interstitial spaces, but also into some alveolar spaces. The ground-glass opacities found in this case may have reflected the infiltration of lymphoma cells into the pulmonary interstitial spaces.

Adrenal Gland Neoplasms↗

[Cryptococcosis].

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Amphotericin B↗

[Two cases of Legionella pneumophila pneumonia improved by parenteral ciprofloxacin administration].

We report here two cases of Legionella pneumophila pneumonia that were markedly improved by parenteral ciprofloxacin administration. A 69-year-old man who had previously visited a hot spring was admitted to our hospital with severe pneumonia and a 48-year-old man with dilated cardiomyopathy as an underlying disease was also hospitalized because of heart failure and pneumonia. In both cases a urinary antigen test for L. pneumophila was negative at the incipient stage, and the initial treatment with a beta-lactam agent was ineffective. However, the high titer of L. pneumophila serogroup 6 antigen in the serum at the convalescent stage revealed that these two pneumonia cases were caused by L. pneumophila, and the following intravenous administration of ciprofloxacin was highly effective. We concluded that intravenous treatment with ciprofloxacin could be effective against L. pneumophila pneumonia, which is sometimes hard to diagnose in the acute phase.

Aged↗

[Two cases of allergic bronchopulmonary mycosis caused by Schizophyllum commune in young asthmatic patients].

We report on two patients, a 27-year-old and a 33-year-old woman, with allergic bronchopulmonary mycosis (ABPM) caused by the basidiomycetous fungus Schizophyllum commune (S. commune). Each patient had bronchial asthma. Both were admitted to our institution for further examination of cough, sputum, and abnormal chest shadows. ABPM was strongly suspected, because they showed eosinophilia in both peripheral blood and sputum, and increased serum IgE levels. A mold was isolated from their sputum, but identification was not possible. Systemic corticosteroid therapy relieved their symptoms and chest abnormal shadows. Later, S. commune, a basidiomycetous fungus, was detected from further examination of their sputum cultures, and serum anti-S. commune IgG was elevated. Finally, both cases were diagnosed as ABPM caused by S. commune. It is reported that this syndrome typically develops in women in middle age, but our patients were young women. It is important to take into account the possibility of ABPM caused by S. commune even in young patients when Aspergillus species are not isolated.

Adult↗

[A case of pulmonary sarcoidosis with cavitation].

A 37-year-old woman, who had first been given a diagnosis of sarcoidosis at 23 years of age, was admitted to our hospital after her condition deteriorated. Chest radiographs and CT scan films showed multiple cavitary lesions with thick walls, diffuse granular shadows and bilateral hilar and mediastinal lymphadenopathy. Skin lesions were also observed. In the bronchoalveolar lavage fluid, no pyogenic bacteria, fungi, acid-fast bacilli or malignant cells were detected. A CT-guided transcutaneus lung biopsy specimen revealed a sarcoid granuloma, and we concluded that the cavitary lesions were due to sarcoidosis. After treatment with prednisolone (30 mg/day), the multiple cavitary lesions, diffuse granular shadows and skin lesions showed obvious improvement.

Adult↗