Biomedical subjects

Tsuyoshi Yamamoto

Publications and source records attributed to Tsuyoshi Yamamoto.

11 recordsLinked to original sources

PubMed2006

[Successful telithromycin therapy of Legionella pneumonia --report of three cases].

Legionella species have been widely recognized as among the important causative organisms of community-acquired pneumonia in Japan. A delay in the start of adequate treatment has a negative influence on the outcome of the disease. Telithromycin, the first oral ketolide antibacterial, was developed for the treatment of community-acquired pneumonia, including Legionella pneumonia. However, few reports have indicated the efficacy of telithromycin in community-acquired pneumonia caused by Legionella species. We report three cases of Legionella pneumonia, that were improved by early telithromycin therapy. The first patient (67-year-old man) had bronchiectasis as an underlying disease, and the second patient (73-year-old man) had diabetes mellitus and chronic renal failure. The third patient (62-year-old man) developed pneumonia after a spa tour. The diagnosis of Legionella pneumonia was made on the basis of the presence of a single IgG titer of 1/256 in case 1 and positive antigenuria in cases 2 and 3. The patients were classified into a mild group (case 1) and a moderate group (cases 2 and 3) based on the severity of the community-acquired pneumonia according to the 2005 Japanese Respiratory Society Guidelines. The results support the efficacy of telithromycin in mild to moderate Legionella pneumonia.

Aged↗

PubMed2005

Protein-bound polysaccharide isolated from basidiomycetes inhibits endotoxin-induced activation by blocking lipopolysaccharide-binding protein and CD14 functions.

The protein-bound polysaccharide isolated from basidiomycetes (PSK) is a biological response modifier capable of exhibiting various biological activities, such as antitumor and antimicrobial effects. In the present study, we found that PSK suppressed interleukin (IL)-6 production in murine peritoneal macrophages stimulated with endotoxic lipopolysaccharide (LPS) and its synthetic lipid A (compound 506). Nitric oxide production and p38 mitogen-associated protein kinase phosphorylation induced in a murine macrophage cell line, J774-A1, by LPS and compound 506 were also inhibited by PSK. Further, PSK distinctly suppressed nuclear factor-kappaB activation in Ba/F3 cells expressing mouse Toll-like receptor 4 and MD-2, following stimulation with LPS and compound 506, however, not with Taxol. These PSK-induced inhibitory activities were caused by inhibition of the physical associations of LPS with LPS-binding protein (LBP) and CD14. PSK also protected mice from LPS-induced lethality, presumably by down-regulating IL-6 and tumor necrosis factor-alpha concentrations in serum. These findings indicate that PSK, which also has an ability to regulate LBP/CD14 functions, may be useful for clinical control of endotoxic sepsis.

Acute-Phase Proteins↗

PubMed2005

Recent advances in interventional radiology for acute massive pulmonary thromboembolism.

Acute massive pulmonary thromboembolism is life-threatening and requires vigorous treatment. Anticoagulation is the most traditional treatment for pulmonary thromboembolism, but may not be sufficient for massive thromboemboli. Systemic thrombolytic therapy and surgical thrombectomy are the traditional therapeutic options in this situation. Catheter-directed thrombolysis, percutaneous embolectomy and, more recently, percutaneous thrombus fragmentation techniques using specialized devices are now available to treat the most severe cases of massive pulmonary thromboembolism. The success of these techniques depends on a thorough understanding of the mechanism of action of each of the devices and familiarity with the relevant catheterization techniques. We present a review of currently available equipment and techniques, and describe our work with hybrid treatment using a combination of mechanical fragmentation, localized fibrinolysis and clot aspiration.

Acute Disease↗

PubMed2005

[Clinical analysis of 10 cases of chest wall tuberculosis].

AIM/METHODS: A series of 10 cases of chest wall tuberculosis (man/woman=7/3, average age 62 +/- 17 years old) during past seven years were reviewed. RESULTS: Acid-fast bacillus was detected from an abscess in 60% by smear, 30% by culture, and 75% by polymerase chain reaction (PCR). It was characteristic that enhanced CT of abscess revealed a low density mass with peripheral enhancement, 'rim enhancement findings', in all cases. CT also showed ipsilateral pleural thickening in all cases, suggesting lymphogenous pathogenesis of chest wall lesions from tuberculous pleurisy. As for the treatment, antituberculosis chemotherapies were done in all cases. In addition, open drainage was done in 8 cases and curettage of abscess was performed in 5 cases. None of these ten cases had relapsed during the follow-up periods for 12 to 77 months. CONCLUSIONS: Chest wall tuberculosis is still important as a disorder of a chest wall mass requiring differential diagnosis. Contrasting CT is thought to be useful for the diagnosis. It should be emphasized that 50% of the cases had good outcome without curettage.

Adult↗

PubMed2004

Prefrontal cortical activation associated with working memory in adults and preschool children: an event-related optical topography study.

It is well known that lateral areas of the prefrontal cortex (LPFC) play a central role in working memory (a critical basis of various cognitive functions), but it remains unknown whether the LPFC of children of preschool age is responsible for working memory. To address this issue, we adopted a recently developed non-invasive imaging technique, optical topography (OT), which can potentially be applied to functional mapping in childhood. We firstly examined changes of activity in the LPFC using OT while adult subjects performed an item-recognition task, which requires working memory, under different memory-load conditions. We observed activation in the bilateral LPFC during performance of this task, the magnitude of which differed depending on memory-load. Then, we applied the same technique on 5- and 6-year-old children and observed the activation associated with working memory in the LPFC. Areas and properties of such activity were similar in adults and preschool children. Thus, for the first time, we demonstrate that the LPFC of preschoolers is active during working memory processes, indicating that in 5- and 6-year-old children, the LPFC has already developed processing of this important cognitive function.

Adult↗

PubMed2004

[A case of gastric cancer complicated with multiple lung metastases responding to TS-1].

A 56-year-old gastric cancer patient with multiple lung metastases and dilated cardiomyopathy was treated by chemotherapy with TS-1. This case was judged to be unresectable. TS-1 (100 mg/body/day) was orally administered for 4 weeks followed by a drug-free 2-week period as 1 course. At the completion of 3 courses, the multiple lung metastases were assessed to show a complete response (CR). There were no side effects and no hospitalization. This chemotherapy is being continued, and a CR in the lung and no change of the gastric cancer have been maintained for 15 months (10 courses).

Administration, Oral↗

PubMed2003

Optical topography: practical problems and new applications.

We will briefly review the present status of optical topography and then discuss the method of improving practicality, i.e., the signal-to-noise (S/N) ratio and the spatial resolution in observations of higher-order brain functions. The optimum wavelength pair improved the S/N ratio sixfold for deoxyhemoglobin, and new configurations of light irradiation and detection positions doubled the spatial resolution. We also report on developing application fields of optical topography. This modality will bridge the gap between natural sciences, neuroscience, and pedagogy, and show actual real-time brain activity.

Brain↗

PubMed2003

Clinicopathological features of pancreatic intraepithelial neoplasias and their relationship to intraductal papillary-mucinous tumors.

Pancreatic intraepithelial neoplasia (PanIN) is a recently proposed nomenclature for putative precursor lesions of pancreatic cancer, which are designated as PanIN-1 through -3 according to their increasing grade of dysplasia. A stepwise progression model of PanINs has been proposed, and multistep genetic alterations in PanINs are being investigated. PanIN-1A and PanIN-1B may remain unchanged for a long period. PanIN-3 potentially progresses toward invasive ductal carcinoma (IDC), and there are several case reports suggesting such progression. In these reported patients, PanIN-3 was found in specimens from partial pancreatectomies, and IDC manifested in the pancreatic remnant 17 months to 29 years after the surgery. We describe herein a patient with PanIN-3, in whom IDC manifested in the distal remnant pancreas 69 months after segmental pancreatectomy. Of the reported cases, including the present one, four of the patients were male and three were female, and the age at the first operation ranged from 46 to 70 years. Intraductal papillary-mucinous tumor (IPMT) is an entity that is distinct from PanIN. However, IPMTs of small size resemble PanINs morphologically. Loss of Dpc4 expression has been reported in the invasive component of IPMT, as well as in PanIN-3 and IDC. Analysis of mucin expression patterns has been reported, suggesting that, in practice, MUC1-positive MUC2-negative IPMTs may not be distinguishable from PanINs. There may be overlapping lesions between PanINs and IPMTs. Should the paradigm of the ductal origin of IDC be accepted, PanINs and a fraction of IPMTs would represent precursors of IDC.

Aged↗

PubMed2003

[Problems about the management of active pulmonary tuberculosis patients undergoing haemodialysis--our experiences and nation-wide questionnaire survey].

UNLABELLED: End-stage renal failure patients on chronic dialysis are high risk groups of tuberculosis due to attenuated cellular immunity. Patients receiving haemodialysis stay prolonged time inside the health-care facilities, thereby increased risk of tuberculosis transmission if a patient has active disease. So management of active pulmonary tuberculosis undergoing haemodialysis is important, however, the number of hospitals which are capable of taking care of such patients is estimated to be few in Japan. METHODS: From August 1994 through July 2002, 1059 active pulmonary tuberculosis patients (mean age; 57 +/- 19, male/female = 773/286) were admitted to Nishi-Kobe Medical Center, a 500-bed teaching hospital. Out of them, patients undergoing haemodialysis were retrospectively studied to describe the clinical characteristics of such cases. Then we conducted a questionnaire survey regarding the management of active pulmonary tuberculosis patients undergoing haemodialysis for 86 self-governing bodies in Japan. RESULTS: (1) Clinical characteristics of active pulmonary tuberculosis undergoing haemodialysis. We encountered 14 cases (mean age; 65 +/- 11, male/female = 7/7) of pulmonary tuberculosis undergoing haemodialysis during 8 years. In addition to pulmonary involvement, 3 pleural, one knee joint and one lymph node involvement was detected. Primary renal disease included diabetic nephropathy (n = 3), chronic glomerulonephritis (n = 3), congenital anomaly (n = 1), and unknown (n = 7). Nine cases were referred to our hospital from health-care facilities located out of city or prefecture. In five cases it took more than three months from the onset or detection of abnormal chest X-ray findings to the admission to our hospital. Five cases developed pulmonary tuberculosis within the first year after the initiation of dialysis. None of the patients had a past history of tuberculosis. Cavitary lesion on chest X-ray was observed in only one case. Triple antituberculosis therapy was used in 9 patients, and 4 antituberculosis drugs were used in 5 patients. Antituberculosis therapy was successfully done in all cases except two patients who died of apoplexy and cerebral infarction. (2) The nation-wide questionnaire survey. Of the 86 self-governing bodies we mailed, 66 self-governing bodies replied. Of them, 31% reported that they have experienced difficulties in the management of active pulmonary tuberculosis patients undergoing haemodialysis, and 25% reported the lack of health-care facilities to take care of such cases in their territory. They have referred such patients to hospitals located in the nearby prefectures or they have recommended antituberculosis therapy visiting a local haemodialysis facility. CONCLUSION: There are sometimes difficulties to manage active pulmonary tuberculosis patients undergoing haemodialysis in Japan. Health-care facilities to take care of such patients should be arranged and the formation of the network is necessarily.

Acute Disease↗

PubMed2002

Arranging optical fibres for the spatial resolution improvement of topographical images.

Optical topography is a method for visualization of conical activity. Ways of improving the spatial resolution of the topographical image with three arrangements of optical fibres are discussed. A distribution of sensitivity is obtained from the phantom experiment, and used to reconstruct topographical images of an activation area of the brain with the fibres in each arrangement. The correlations between the activated area and the corresponding topographical images are obtained, and the effective arrangement of the optical fibres for improved resolution is discussed.

Brain↗

PubMed2002

512-channel vertical-cavity surface-emitting laser based free-space optical link.

A vertical-cavity surface-emitting laser based bidirectional free-space optical interconnect has been implemented to interconnect two printed circuit boards. A total of 512 clustered channels with a density of 2844 channels/cm2 are transmitted over a distance of 83 mm. The optical interconnect is a combination of refractive microlenses and diffractive minilens relays.

Journal Article↗