Search PubMed⌕ Search

Biomedical subjects

S Yoshida

Publications and source records attributed to S Yoshida.

At least 541 records · Page 30Linked to original sources
PubMed1999

Plasticity-related serine proteases in the brain (review).

Serine proteases exert a variety of functions in the body; food digestion, regulation of other proteins and modification of extracellular matrix. Cumulative evidence has shown the importance of serine proteases in the nervous system as well. It has been shown that three serine proteases, thrombin, plasminogen activators and neuropsin, have functional roles in neural plasticity. Most of the actions of thrombin are thought to be mediated by its specific receptors. Thrombin reverses neurite outgrowth of serum-deprived neuroblastoma cells, and induces protective and apoptotic effects on neurons and glial cells depending on concentration and time. Tissue-type and urokinase-type plasminogen activators (tPA and uPA) distribute broadly in the brain. tPA and uPA exert a variety of functions during development. These proteases also function in long-term potentiation and kindling formation. Furthermore, tPA is essential to excitotoxic neuronal cell death. Neuropsin is a serine protease expressed in the limbic system of the brain. Kindling induced neuropsin mRNA and protein expression and anti-neuropsin antibody ameliorates kindling epilepsy. The possible roles of these proteases in neural plasticity are reviewed here.

Animals↗
PubMed1999

Lung metastasis suppression of the bifunctional new radiosensitizer KIN-806.

KIN-806 is one of the newly developed 2-nitroimidazole derivative hypoxic cell radiosensitizers. The tumor growth control and the suppression of lung metastasis induced by KIN-806 were evaluated. Female C3H/He mice and SCCVII tumor cells were used. 30 Gy or 40 Gy was delivered as local irradiation. 0.2 g/kg or 0.4 g/kg KIN-806 was administered 30 min before this treatment to the KIN-806 administered groups. The enhancement ratio of KIN-806 evaluated using the growth delay method was 1.8. KIN-806 showed an excellent effect as a radiosensitizer. Furthermore, KIN-806 suppressed lung metastasis regardless of radiation, and the control of the metastatic lung nodules did not depend on the irradiation dose but rather on the KIN-806 dose (0.2 g/kg < 0.4 g/kg). KIN-806 is a promising bifunctional radiosensitizer which promotes anti-tumor activity in addition to having a radiosensitizing effect.

Animals↗
PubMed1999

[Acute otitis media associated with bone conduction hearing loss].

Eleven patients (12 ears) with acute otitis media associated with raised bone conduction were studied. The patients were from 19 to 70 years old and came to our hospital between November 1996 through May 1997. Pure tone audiometry revealed mixed hearing loss, but there was no bullous myringitis in all cases. They were treated by oral or intravenous antibiotics, steroids, and myringotomy. Bacteriological examination was done in seven cases, and revealed penicillin resistant Streptococcus pnumoniae in three cases. Complete recovery of hearing loss was obtained in 10 of 12 ears, but sensorineural hearing loss remained in 2 patients. Bacteriological examination and pure tone audiometry in acute otitis media are important for detecting the severity of the disease, determining the administration of steroids, and for the selection of antibiotics.

Acute Disease↗
PubMed1999

[Emergency stenting for iatrogenic occlusion of internal carotid artery during percutaneous transluminal angioplasty: a case report].

The authors report the case of a 68-year-old male who underwent emergency stenting for iatrogenic occlusion of the internal carotid artery while he was receiving percutaneous transluminal angioplasty. He presented with a 1-month history of transient ischemic attacks with right-sided hemiparesis. Carotid angiography revealed a 95% eccentric stenosis at the origin of the left internal carotid artery. As the stenotic lesion was higher than the level of the third cervical vertebral body, percutaneous transluminal angioplasty was performed instead of carotid endarterectomy. During the procedure, the left internal carotid artery was dissected, then obstructed completely with rapid deterioration of his neurological condition. The Palmaz-Schatz stent was successfully deployed over the site of dissection to restore normal patency through the dissected carotid artery. Following emergency stenting, his neurological signs quickly subsided. Since then, with oral administration of antiplatelet medication, he has suffered no recurrence of cerebral ischemic events. Echo-ultrasonography 4 months after stent implantation showed good patency of the stented segment. It has been reported that angioplasty is indicated for high-risk patients or surgically inaccessible lesions in stenotic disorders of the internal carotid artery. However, there are several complications reported, including intimal dissection and restenosis. The present case emphasizes the usefulness of emergency stenting when occlusion of the internal carotid artery is complicated during percutaneous transluminal angioplasty.

Aged↗
PubMed1999

[Sjögren's syndrome].

Sjögren's syndrome(SS) is a chronic inflammatory disease characterized by keratoconjunctivitis sicca and xerostomia. According to the epidemiological survey done by the Japan Ministry of Health and Welfare(MHW) in 1994, about 17,000 SS patients visit hospitals and the prevalence rate is approximately 0.06% for females. SS is diagnosed mainly by the criteria of MHW in 1977, and the revised ones will be published in the near future. Several candidates for the corresponding antigens for SS autoimmunity have discovered, such as alpha-fodrin and 203-211 amino acid residues of Ro/SSA-52 kDa. The sicca complex is treated with fluid replacement, but corticosteroids or immunosuppressive drugs are sometimes indicated in the treatment of extraglandular involvement. Several new drugs are now under investigation.

Autoantigens↗
PubMed1999

[Atypical chronic myeloid leukemia presenting with trilineage dysplasia and IgG (lambda) type monoclonal gammopathy].

A 78-year-old man was diagnosed as leukocytosis in February 1994. Physical examination revealed marked hepatosplenomegaly. A peripheral blood examination disclosed 95,090/microliter leukocytes without hiatus leukemicus, 6.5 g/dl Hb, and 15.0 x 10(4)/microliter platelets. The neutrophil alkaline phosphatase score was 27, and serum VB12 was above 1,600pg/ml. IgG was identified as monoclonal immunoglobulin of type lambda. Bone marrow specimens demonstrated marked granulocytic hyperplasia. Neither the Philadelphia chromosome (Ph1) nor BCR gene rearrangement was detected; hence, the diagnosis of Ph1 (-) chronic myeloid leukemia (CML) was made. The patient was treated with hydroxyurea and low-dose VP-16 with no improvement, and died of pneumonia and sepsis in June 1995. This case was considered to be consistent with atypical CML (aCML) according to the FAB classification because monocytosis was not observed. It seems likely and interesting that the coexistent monoclonal gammopathy and aCML might have arisen from common abnormal hematopoietic stem cells.

Aged↗
PubMed1999

[Invasive thymoma associated with pure red cell aplasia and liver metastasis: a case report].

A case of invasive thymoma associated with pure red cell aplasia and liver metastasis was reported. A 57-year-old male was admitted to our hospital because of hepatic abnormal shadow on computed tomography. Malignant tumor was suspected by imaging procedures. Left lateral segmental resection of liver was performed and histo-pathological examination proved the tumor to be liver metastasis of thymoma. He was received 50 Gy irradiation after incomplete resection of thymoma. In the course of time he contracted pure red cell aplasia. But he is well controlled medically and alive 7 years after the surgery.

Humans↗
PubMed1999

Suppression of retinal neovascularization by the NF-kappaB inhibitor pyrrolidine dithiocarbamate in mice.

PURPOSE: To evaluate the effect of pyrrolidine dithiocarbamate (PDTC), an inhibitor of nuclear factor kappaB (NF-kappaB), on retinal neovascularization in a murine model of ischemic retinopathy. METHODS: One-week-old C57BL/6N mice were exposed to 75%+/-2% oxygen for 5 days and then were returned to room air to induce retinal neovascularization. After the return to room air, the left and right eyes were injected intravitreally with PDTC or a vehicle, respectively. Retinal neovascularization was examined by injecting fluorescein dextran and angiography after 5 days in room air and was quantitated histologically with a masked protocol. The effects of PDTC on NF-kappaB activation were evaluated by immunohistochemistry. To examine the toxicity of PDTC, the histologic change in the retina was examined by light and electron microscopy. RESULTS: Retinal neovascularization in the eye injected with PDTC by intravitreal methods was reduced in 100% of animals compared with that apparent in the vehicle-treated eye. The inhibitory effect was dose-dependent, with a maximal inhibition of 39% (P < 0.01) at a dose of 1 nmole. The immunostaining intensity for NF-KB in the retina was reduced by PDTC injections. No side effects by PDTC in the retina were observed by light and electron microscopy. CONCLUSIONS: NF-kappaB activation appears to be required for retinal angiogenesis, given that the administration of PDTC suppressed retinal neovascularization. PDTC may prove beneficial in the treatment of ischemic neovascular diseases such as diabetic retinopathy and retinal vein occlusion.

Animals↗
PubMed1999

Brainstem mechanisms of autonomic dysfunction in encephalopathy-associated Shiga toxin 2 intoxication.

Acute encephalopathy is the major determinant of death in an early stage of Shiga toxin (Stx)-producing Escherichia coli infection. Rapid progress toward refractory hypotension and dysfunction of breathing implies autonomic center dysfunction of patients. To clarify whether autonomic dysfunction becomes an ultimate cause of death in Shiga toxemia, we injected purified Stx2 (20 microg/kg) intravenously into rabbits, and monitored changes in cardiovascular and respiratory function together with renal sympathetic nerve activity (RSNA) in the conscious state. After an approximately 24-hour silent (lag) period, all rabbits given Stx2 developed hemorrhagic diarrhea (25.7 +/- 1.1 hours) and limb paralysis (31.2 +/- 1.3 hours). This limb paralysis was observed initially in the hind legs, and then it gradually extended to the forelegs. After 23.2 +/- 2.3 hours, RSNA increased gradually, and arterial blood pressure was maintained within normal limits together with an increase in the maximum gain of baroreflex response. Severe hypotension developed within 34.8 +/- 2.2 hours, without any increase in heart rate; RSNA significantly increased by 39.5 +/- 0.9 hours. In the final stage, RSNA decreased concurrently with decreases in arterial blood pressure, heart rate, and baroreflex response, suggesting dysfunction of the baroreflex control system. Thereafter, all rabbits died within 47.8 +/- 1.2 hours after the intravenous Stx2 injection. Magnetic resonance imagings of the central nervous system (T2-weighted images) showed high-intensity areas in the dorsal two-thirds of the cervical spinal cord and brainstem 48 hours after Stx2 administration. These results show that the cause of death is circulatory failure caused by impairment of the cardiovascular center in the medulla. We believe that this animal model helps to clarify the mechanism of rapid progress to death of patients with Shiga toxin-producing E. coli infection.

Animals↗
PubMed1999

Vimentin localisation in tooth germ cells of two marsupial species, the northern brown bandicoot, Isoodon macrourus, and the brushtail possum, Trichosurus vulpecula.

In marsupial teeth, long cellular processes from ameloblasts and odontoblasts are found in the developing enamel and dentinal tubules, respectively. It has been suggested that the odontoblast cytoskeleton plays a role in the dentinal tubule formation of rat. To understand the role of the cytoskeleton in the blast cells, the location of vimentin and cytokeratin in the tooth germ of the bandicoot and the possum was examined using immunohistochemical techniques. Vimentin was detected in differentiating and secretory ameloblasts and may be involved with the secretion of fibronectin. Vimentin labelling was much weaker and irregular in cells of the outer enamel epithelium, the stellate reticulum and the stratum intermedium. Dentinal tubules, odontoblasts and dental papilla fibroblasts also stained positively for vimentin. Positive staining for cytokeratin was observed in all cells in the enamel organ but not in the enamel and dentinal tubules or the cells of the dental papillae. The presence of vimentin in the dentinal tubules indicated that the odontoblast processes in these tubules were still active and they extended to near the enamel-dentin junction. In conclusion, the presence of vimentin in tooth germ cells suggests that it may be involved in the formation of enamel tubules in marsupials.

Animals↗
PubMed1999

[Histidine buffered cardioplegic solution (HBS) provides effective myocardial preservation with wider safety margin in patients with prolonged ischemia].

Increasingly complex techniques of cardiac surgery often require prolonged myocardial ischemia. We previously reported a better myocardial preservation with histidine containing cardioplegia (HBS) in human open heart surgery. To see a safety margin of this cardioplegia for prolonged myocardial preservation, this study was retrospectively done. One hundred twenty-six patients received either intermittent multidose (20-30 minute) cold blood cardioplegia (CBC) plus topical cooling (aotric cross clamp time (ACC) < 120 minutes, n = 63) or HBS (n = 63). HBS group was divided into two groups with either short ACC (< or = 120 minutes, HBS-S, n = 46) or long ACC (> 120 minutes, HBS-L, n = 17). Cardiac index (C.I.) and dopamin/dobutamine requirement were measured 3, 6, and 12 hours post-bypass. Incidence of homologous blood transfusion was also studied. There was two deaths due to LOS in HBS-S group; four patients in HBS group required 5 DC cardioversion, whereas six patients required a total of 12 DC cardioversion in CBC group. Functional recovery were significantly better with significantly lower inotropic requirements in HBS-S group than CBC group and HBS-L group. Although preoperative ejection fraction and C.I. were significantly lower in HBS-L group, post-operative cardiac function and inotropic requirements in HBS-L was comparable to that seen in CBC group. We conclude that the highly buffered histidine crystalloid cardioplegia solution provides effective myocardial preservation with a wider safety margin for prolonged myocardial preservation in open heart surgery.

Adult↗
PubMed1999

[Estimation of left internal thoracic artery flow reserve after coronary artery bypass grafting using Doppler flow wire].

The usefulness of the left internal thoracic artery (LITA) for aortocoronary bypass grafting is now established. Reports of variation in LITA graft function are rare. Graft flow was measured using a Doppler flow wire to estimate graft function in 27 patients (24 males, 3 females) who underwent LITA grafting to the left anterior descending artery. Patients were classified into the following 3 groups: Group A consisted of 9 patients with normal left ventricular function and no native flow; Group B consisted of 11 patients with normal ventricular function and good native flow; Group C consisted of 7 patients with abnormal left ventricular function and no native flow. LITA graft function was also estimated 1 year after operation in 12 of these 27 patients (4 in each group). Diastolic/systolic velocity ratio (DSVR) and flow reserve were determined in the proximal, middle, and distal portions of the LITA graft and native left anterior descending artery before and after papaverine administration (8-10 mg). DSVR was significantly higher in the distal portion than in the proximal portion (p < 0.01), but this value did not change after papaverine administration. After 1 year, DSVR in the proximal portion was significantly higher in Group C than in Groups A or B (p < 0.05 for both). Four weeks after operation, the flow reserve of the distal portion was significantly higher in Group A than in Group C (p < 0.001). After 1 year, this value was significantly higher in Group A than in either Groups B or C (p < 0.01, p < 0.001, respectively). The rate of increase in flow reserve in the distal portion was significantly greater in Group A (23.4%) than in groups B (2.53%) or C (1.94%; p < 0.05 for both). The distal portion of the LITA was the best measurement site, since the flow pattern in the LITA graft varied throughout all portions. Diastolic flow velocity in the LITA graft was dominant in patients with myocardial damage. The results indicate that flow reserve of the LITA graft depends on antegrade native coronary flow and distal myocardial damage.

Coronary Artery Bypass↗
PubMed1999

[Chemoradiation therapy for advanced esophageal cancers--report of 3 cases].

Three cases of prominent-type advanced esophageal cancer were treated with chemoradiation therapy using a 5-FU analog and low dose CDDP. All cases showed a complete response after the treatment. Only mild bone marrow suppression was found in one case. This protocol will be applied for patients with prominent-type advanced esophageal cancers, especially high risk patients.

Aged↗
PubMed1999

Gains of 1q21-q22 and 13q12-q14 are potential indicators for resistance to cisplatin-based chemotherapy in ovarian cancer patients.

The mechanism of drug resistance in ovarian cancer is multifactorial, and accumulation of multiple genetic changes may lead to the drug-resistant phenotype. In our attempt to find characteristic genetic changes in drug-resistant tumors, we screened the whole genome for gene aberrations in 28 primary ovarian cancers using the comparative genomic hybridization method. These cancers included 14 tumors from patients who did not respond to cisplatin-based combination chemotherapy and 14 tumors from patients who had complete response to the chemotherapy. We found gains in chromosomal regions 1q21-q22 and 13q12-q14 to be related to the drug-resistant phenotype in ovarian cancer patients. Several genes encoding transcription factors, oncogenes, cell cycle regulators, and regulators of the apoptotic pathway are located on these regions of the chromosomes, and these genes are potential modulators for toxic insults in cancer cells. This is the first report that shows the relationship between certain genomic aberrations and clinical resistance to cisplatin-based chemotherapy in ovarian cancer patients based on the comparative genomic hybridization analysis. Present findings suggest that these chromosomal gains may be potential indicators for prediction of resistance in ovarian cancer patients before cisplatin-based chemotherapy.

Antineoplastic Agents↗
PubMed1999

Coronary artery aneurysm associated with fistula in adults: collective review and a case report.

Coronary artery fistulae (CAF) are infrequent congenital anomalies. The combination of coronary artery aneurysms and coronary artery fistulae (coronary artery aneurysm associated with fistula, CAAAF) is extremely rare, and only 50 cases, including the current case, have been reported. Coronary artery fistulae may result in coronary ischemia, congestive heart failure, and endocarditis. Complications of coronary artery aneurysms include thrombosis, distal emboli, and aneurysm rupture. Aneurysm repair, fistulous closure and/or coronary artery bypass grafts are definite treatments for CAAAF. We present here a 72-year-old female with CAAAF. Furthermore, all reported CAAAF cases are reviewed.

Aged↗