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Hiroki Morita

Publications and source records attributed to Hiroki Morita.

13 recordsLinked to original sources
PubMed2006

Pharmacokinetic study of pleural fluid penetration of carbapenem antibiotic agents in chemical pleurisy.

STUDY OBJECTIVES: We investigated pleural fluid penetration of carbapenem antibiotic agents [imipenem (IPM), panipenem (PAPM), meropenem (MEPM), and biapenem (BIPM)] using an experimental rabbit pleuritis model to clarify the usefulness of the carbapenem agents for the treatment of bacterial pleurisy or pyothorax. MEASUREMENTS AND RESULTS: Serum and pleural fluid specimens were serially collected at 5, 10, 15, 30, 60, 90, 120, 180, 240, 300, and 360 min after antibiotic administration for measurement of antibiotic levels. We investigated each agent alone as well as drug solutions containing each agent and a dehydropeptidase-I-specific inhibitor, cilastatin (CS), to remove the influence of dehydropeptidase-I-related hydrolysis. Groups of animals (n=3) received each carbapenem agent with or without CS. Serum and pleural fluid antibiotic levels were measured by high-performance liquid chromatography (HPLC). Because Cmax is not useful for evaluating the antimicrobial effects of carbapenem antibiotic agents due to their dose-dependent antimicrobial activity, we also investigated the AUC, which is correlated with the total drug levels in vivo. Among the drug solutions containing CS, MEPM/CS had the highest pleural fluid AUC0-360 (1594.8+/-510.3 microg min/ml), and the highest pleural fluid AUC0-360/plasma AUC0-360 ratio (0.79+/-0.04). BIPM/CS had the highest plasma AUC0-360 (3040.1+/-1525.9 microg min/ml). In pleural fluid AUC0-360/plasma AUC0-360 ratio MEPM/CS was significantly higher than those for the remaining agents. In pleural fluid AUC0-360 and plasma AUC0-360 there were no significant differences among these mixed solutions. CONCLUSIONS: MEPM had the most favorable pleural fluid penetration. Pleural fluid penetration should be examined in infection models and in clinical trials.

Animals↗
PubMed2005

Combined effects of panipenem and aminoglycosides on methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa in vitro.

BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa are the main causes of refractory infections that are often resistant to antimicrobial agents. In these cases, combination of agents with antimicrobial activity is being examined. However, few studies have investigated combined effects with antimicrobial agents including carbapenem and aminoglycosides. METHODS: We evaluated the effects of panipenem (PAPM) combined with 3 aminoglycosides, arbekacin, amikacin, and netilmicin, and vancomicin (VCM) with an agar dilution checkerboard technique and the fractional inhibitory concentration index against 47 strains of MRSA and 56 strains of P. aeruginosa. RESULTS: PAPM combined with VCM achieved a synergic effect against MRSA in 80.9%. PAPM combined with aminoglycosides showed only additive effects against MRSA and P. aeruginosa. When comparing the activity of Mueller-Hinton agar (MHA) medium with MHA medium diluted 40-fold (1/40 MHA) against P. aeruginosa, the mean minimum inhibitory concentration of PAPM was decreased to 1/16. CONCLUSIONS: Combination of PAPM and VCM is effective against MRSA. Combinations of PAPM and aminoglycosides showed additive effects against MRSA and P. aeruginosa.

Aminoglycosides↗
PubMed2005

Isolation of nontuberculous mycobacteria from patients with pneumoconiosis.

This study aimed to confirm the isolation of nontuberculous mycobacteria (NTM) from patients with pneumoconiosis. Monthly sputum examinations in 155 patients were performed from April 1998 to December 2002. When NTM were isolated, species were identified and the frequency of isolation was reviewed. We then identified the patients who satisfied the bacteriologic criteria for the diagnosis of nontuberculous mycobacterial pulmonary disease (NTM pulmonary disease) recommended by the American Thoracic Society (ATS). Symptoms and findings on computed tomography (CT) scans were evaluated. NTM were isolated from 60 patients (39%): common etiologic species defined by the ATS, i.e., Mycobacterium avium, M. intracellulare, M. abscessus, and M. kansasii, were identified in 21 patients; unusual etiologic species, i.e., M. fortuitum, M. simiae, and M. szulgai, were identified in 11 patients; and undefined species, which appeared to be nonpathogenic, were identified in 41 patients. The bacteriologic criteria were satisfied in 8 patients. NTM species isolated in conformity with the bacteriologic criteria were: M. avium in 4 patients, M. intracellulare in 2, a combination of M. intracellulare and M. kansasii in 1, and M. gordonae in 1 patient. Two patients, from whom M. avium were repeatedly isolated, satisfied the ATS diagnostic criteria for NTM pulmonary disease. It is important to note that NTM, including both pathogenic species and nonpathogenic species, were isolated from patients with pneumoconiosis.

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PubMed2005

Bronchoscopic intralesional injection of triamcinolone acetonide treated against bronchial obstruction caused by peanut aspiration.

We encountered a case of obstructive pneumonia 1 month after peanut aspiration. Bronchoscopic examination revealed obstruction of the right basal bronchus with immature granulation tissue due to the peanut aspiration. Despite antibiotic treatment, the obstruction had not been resolved. To relieve the bronchial obstruction, bronchoscopic intralesional injection of triamcinolone acetonide was performed without any complications. Seven days after injection, the bronchial obstruction had resolve. In conclusion, intralesional injection of triamcinolone acetonide may play a role in one of the non-surgical repairs against obstruction due to foreign body aspiration.

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PubMed2004

Paracrine regulation of mammalian oocyte maturation and male germ cell survival.

Mammalian oocytes are arrested at the prophase of meiosis before induction of maturation by the preovulatory luteinizing hormone (LH) surge. LH also promotes the survival of meiotic male germ cells in the testis. Because LH binds somatic cells, the mechanism underlying its regulation of germ cell function is unclear. We found that LH stimulates Leydig insulin-like 3 (INSL3) transcripts in ovarian theca and testicular Leydig cells. INSL3, in turn, binds a G protein-coupled receptor, LGR8 (leucine-rich repeat-containing G protein-coupled receptor 8), expressed in germ cells to activate the inhibitory G protein, thus leading to decreases in cAMP production. Treatment with INSL3 initiates meiotic progression of arrested oocytes in preovulatory follicles in vitro and in vivo and suppresses male germ cell apoptosis in vivo, thus demonstrating the importance of the INSL3-LGR8 paracrine system in mediating gonadotropin actions.

Animals↗
PubMed2004

Identification of novel hepatitis C virus-specific cytotoxic T lymphocyte epitopes by ELISpot assay using peptides with human leukocyte antigen-A*2402-binding motifs.

The human leukocyte antigen (HLA)-A*2402 is common in Asians. The authors attempted to identify epitopes for HLA-A*2402-restricted, hepatitis C virus (HCV)-specific CD8(+) T cells by an enzyme-linked immunospot (ELISpot) assay using peripheral blood CD8(+) T cells from HLA-A*2402-positive hepatitis C patients and synthetic HCV peptides based on HLA-A*2402-binding motifs and the amino acid sequence of type 1b HCV. Ten novel epitopes were identified in five of seven HLA-A*2402-positive patients with acute or short-term chronic HCV infection (<3 years), but in none of four with longer-term chronic infection (>10 years). Only one of the ten epitopes proved to be definitely HLA-A*2402-restricted. Another epitope was identified in one of two HLA-A*2402-negative acute hepatitis C patients. In two of the six patients with positive CD8(+) T cell responses, the targeted epitopes were multiple. The same epitope was targeted in two patients. When patients with unresolved acute HCV infection were treated with alpha interferon, peripheral blood HCV-specific CD8(+) T cells decreased with resolution of the hepatitis. In conclusion, CD8(+) T cell responses to HCV infection are heterogeneous. One definite HLA-A*2402-restricted and ten probably non-HLA-A*2402-restricted epitopes were identified. Patients with short-term HCV infection are suitable for searching for novel HCV epitopes, but peripheral blood HCV-specific CD8(+) T cells decrease markedly after loss of antigenic stimulation.

Binding Sites↗
PubMed2004

Neonatal lethality of LGR5 null mice is associated with ankyloglossia and gastrointestinal distension.

The physiological role of an orphan G protein-coupled receptor, LGR5, was investigated by targeted deletion of this seven-transmembrane protein containing a large N-terminal extracellular domain with leucine-rich repeats. LGR5 null mice exhibited 100% neonatal lethality characterized by gastrointestinal tract dilation with air and an absence of milk in the stomach. Gross and histological examination revealed fusion of the tongue to the floor of oral cavity in the mutant newborns and immunostaining of LGR5 expression in the epithelium of the tongue and in the mandible of the wild-type embryos. The observed ankyloglossia phenotype provides a model for understanding the genetic basis of this craniofacial defect in humans and an opportunity to elucidate the physiological role of the LGR5 signaling system during embryonic development.

Animals↗
PubMed2004

[A case of pulmonary nocardiosis with a polypoid lesion in a bronchus].

A 62-year-old woman was admitted with fever and bloody sputum. A mass shadow in the left S3 and obstruction of the left B3 were seen on a chest radiograph and CT. Obstructive pneumonia was suspected, and cefotiam and imipenem/cilastatin were administered. However, this treatment did not show adequate efficacy. Bronchoscopy demonstrated a yellowish-white polypoid lesion in the left B3, but histopathological findings with HE staining yielded no definite diagnosis. Subsequently, Nocardia asteroides was detected in sputum test. A sulfamethoxazole-trimethoprim combination and minocycline were administered, and the clinical findings improved. Gram-positive microfilaments were confirmed retrospectively in the pathologic specimen, and a diagnosis of pulmonary nocardiosis was made.

Anti-Bacterial Agents↗
PubMed2002

Chronic necrotizing pulmonary aspergillosis in pneumoconiosis: clinical and radiologic findings in 10 patients.

STUDY OBJECTIVE: To characterize clinical, radiographic, and CT findings of chronic necrotizing pulmonary aspergillosis (CNPA) in patients with pneumoconiosis. METHODS: We studied 10 patients with pneumoconiosis who were seen at Asahi Rosai Hospital and received a clinical diagnosis of CNPA during a 15-year period, and detailed the long-term clinical and radiologic courses of four cases. RESULTS: All patients were men, ranging in age from 48 to 77 years (mean, 60.1 years). Their occupational histories included pottery making (n = 9) and coal mining (n = 1). Chest radiographic findings by the International Labor Organization profusion grading system were greater than category 2. All patients were symptomatic, with a productive cough, hemoptysis, and dyspnea. Serum findings were positive for the Aspergillus antibody in seven patients. The radiologic findings consisted of parenchymal infiltrates and cavities mostly containing mycetoma, which generally involved the upper lobes. The disease progressed slowly; in one patient, broad destruction of the lung was observed after > 10 years without antifungal administration. Most of the patients experienced clinical and radiologic improvement after receiving antifungal therapy, by oral, inhaled, or intracavitary administration. CONCLUSIONS: Chronic persistent or progressive upper-lobe infiltrates and cavities in patients with pneumoconiosis should raise the possibility of CNPA. Early diagnosis and initiation of effective therapy are recommended to achieve a better outcome.

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