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Biomedical subjects

S Yamazaki

Publications and source records attributed to S Yamazaki.

At least 109 records · Page 6Linked to original sources
PubMed2000

Circadian rhythm of ERG in Iguana iguana: role of the pineal.

In green iguanas, the pineal controls the circadian rhythm of body temperature but not the rhythm of locomotor activity. As part of a program to investigate the characteristics of this multioscillator circadian system, the authors studied the circadian rhythms of the electroretinographic response (ERG) and asked whether the pineal gland is necessary for the expression of this rhythm. ERGs from a total of 24 anesthetized juvenile iguanas were recorded under four different conditions: (a) complete darkness (DD), (b) dim light-dark cycles (dLD), (c) constant dim light (dLL), and (d) pinealectomized in DD. Results demonstrate that the b-wave component of the ERG shows a very clear circadian rhythm in DD and that this rhythm persists in dLL and entrains to dLD cycles. The ERG response is maximally sensitive during the subjective day. Pinealectomy does not abolish the circadian rhythm in ERG, demonstrating that the oscillator responsible for the ERG rhythm is located elsewhere.

Animals↗
PubMed2000

Liposteroid therapy for refractory seizures in children.

Liposteroid is dexamethasone palmitate incorporated into liposomes and was developed as an anti-inflammatory drug for targeting therapy mainly for rheumatoid arthritis. Recently, it was reported that liposteroid might be effective for the treatment of West syndrome, with fewer side effects than those of corticotropin therapy. We describe three patients, a 2-month-old boy with early infantile epileptic encephalopathy, a 4-month-old girl with symptomatic West syndrome, and a 2-year-old girl with symptomatic localization-related epilepsy, whose refractory seizures were treated with liposteroid according to the original method reported by Yamamoto and colleagues in 1998. Uncontrollable seizures ceased completely in two patients and the seizure frequency decreased markedly in the other patient. Electroencephalograms revealed marked improvement in all patients. They showed no relapse of the seizures, and all showed no adverse effects except for mild brain shrinkage in one patient. Our experience with these three patients suggests that liposteroid therapy might be a new option for the treatment of refractory seizures in children, as well as for West syndrome.

Anti-Inflammatory Agents↗
PubMed2000

Improved synthesis of paroxetine hydrochloride propan-2-ol solvate through one of metabolites in humans, and characterization of the solvate crystals.

Paroxetine, a potent and selective inhibitor of 5-hydroxytryptamine (serotonin) uptake, was prepared through a piperidine derivative, which was reported to be one of the paroxetine metabolites in humans. Thus, the piperidine derivative was converted to its N-tert-butoxycarbonyl (N-Boc) derivative, which was then converted to N-Boc paroxetine. Paroxetine hydrochloride propan-2-ol (isopropyl alcohol (IPA)) solvate crystals were directly obtained from the N-Boc paroxetine by adding hydrogen chloride to the N-Boc paroxetine IPA solution. The amount of IPA content in the crystals was reduced by drying with a continuous change of powder X-ray diffraction patterns. Other characterizations of the solvate crystals were also conducted.

Crystallography, X-Ray↗
PubMed2000

[Analysis of contact dermatitis by cytokines 4--Skin sensitization of biphenyl compounds].

Clove buds oil is one of very important natural essential oil with a typical spicy note and also known as a source of eugenol. These phenol compounds, which have the strong perfume of clove, are widely used not only as an analgesic and antiseptic agent in dentistry. However, the problem is that the phenol compounds caused sensitization on the skin occasionally. We reported that the skin sensitization by eugenol and its derivatives was detected in the guinea pig maximization test (GPMT) and also confirmed that dehydrodi-eugenol, a biphenyl compound of eugenol, did not show the skin sensitization. To discuss more, we examined the skin sensitization by several phenol compounds and its biphenyl ones. Consequently, we confirmed that the skin sensitization by biphenyl compounds more remarkably decreased than that by phenol compounds (monomer).

Animals↗
PubMed2000

Inducible nitric oxide-mediated myocardial apoptosis contributes to graft failure during acute cardiac allograft rejection in mice.

The mechanism through which nitric oxide (NO) mediates cardiac myocyte death during acute cardiac rejection has not been fully delineated. We sought to determine whether NO promotes myocardial apoptosis and contributes to graft failure during acute cardiac rejection in a murine model. Heterotopic cardiac transplantation was performed from Balb/c (H-2d) to C3H/He mice (H-2k). Recipients were treated with aminoguanidine (AG) at 400 mg/kg every day after surgery. As references, we used isografts in Balb/c mice with and without AG treatment (400 mg/kg/day). Graft survival, histological changes and serum NO levels were assessed. Intra-graft apoptosis was evaluated using a DNA fragmentation detection assay (TUNEL method) and DNA laddering. Significant prolongation of graft survival was observed in allografts treated with AG in comparison with nontreated allografts. Serum NO levels, which peaked on day 7 in nontreated allografts, were significantly decreased in AG-treated allografts. AG treatment decreased the number of apoptotic cells and lowered the ratio of the apoptotic cardiac myocytes in contrast to that of the apoptotic infiltrating cells. DNA laddering was clearly detected in nontreated allografts but was suppressed in AG-treated allografts. Inhibition of NO production by AG prolonged murine cardiac allograft survival. The decrease in intra-graft apoptotic activity paralleled histological improvement. Cardiac myocyte death which occurs through an apoptotic process mediated by NO contributes to graft failure during acute cardiac rejection.

Animals↗
PubMed2000

Effects of intestinal muscular wrapping on remnant intestinal motility after massive small bowel resection in conscious canines.

We searched the effect of the muscular valve on the management of short bowel syndrome. The motility of the remnant intestine with a special muscular valve after 80% massive distal small bowel resection (MSBR) was evaluated in conscious dogs. The valve (muscular ring) was made by the autointestinal muscle layer holding vascular pedicle. Interdigestive and postprandial bowel motility using bipolar electrodes and/or contractile strain gauge force transducers 2-4 weeks after the surgery, and data of this group (Group I) were compared to the motility in dogs after MSBR without valve construction (Group II) and in controls (Control). Results; Fasting duodenal migrating myoelectric (or motor) complexes (MMCs) in Group I occurred at longer intervals than in Control and almost similarly to those in Group II. MMCs arising from the duodenum were often interrupted before the jejunum above the valve and the anastomosis. The velocity of duodenal MMC propagation was slowed in every intestinal segment including that from the duodenum to the proximal jejunum, and to the jejunum above the anastomosis. Transit time in MSBR group (I and II) from the duodenum to the terminal ileum was extremely shorter than in Control, but there were no differences between in Groups I and II. The duration of the postprandial period without duodenal MMCs in Group I was significantly prolonged than in Control, but was shorter than that in Group II. The muscular valve was frequently activated, and the jejunum covered with the valve was contracted frequently which synchronized with the valve activity. It seemed the valve worked as sphincter. However, intestinal obstruction was not occurred through the jejunum covered by the valve. In conclusion, changes in gut motility after MSBR with the valve construction compensate for the shortened intestine and maintain the bowel content earlier postoperatively in comparison with the MSBR alone, and also contribute to the adaptive increase in the remnant intestinal absorption.

Animals↗
PubMed2000

[Surgical treatment for bilateral multiple lung cancers].

We reviewed 12 patients with contralateral bronchogenic carcinomas. Seven of them had metachoronous carcinomas and 5 had synchronous carcinomas. We treated 3 patients with lobectomy on both lungs, and 4 patients with lobectomy and segmentectomy, 2 patients with lobectomy and wedge resection, 2 patients with segmentectomy and thoracoscopic wedge resection, and one patient with lobectomy and ablation on each lung. Two patients who had lobectomy on both lungs were dead, one of whom of bronchofistula on operation and the other of respiratory failure 7 years and one month after second operation. The 5-year survival rate in 12 patients was 68.5% after first operation and 82.5% after second operation. We conclude that lobectomy on both lungs are not recommended because of high mortality rate and the limited resection should be considered to treat the other contralateral primary lung cancers. Because the patients with primary lung cancers have the possibility to suffer from new primary cancers in the different site of the lung, we need careful follow up of the patients after treatment on the first lung cancer.

Adenocarcinoma↗
PubMed2000

Standard method for describing an electronic patient record template: application of XML to share domain knowledge.

A Template Definition Language (TDL) was developed to share knowledge of how to construct an electronic patient record (EPR) template. Based on the extensible markup language XML, TDL has been designed to be independent of EPR platforms or databases. Our research of TDL was conducted through evaluation of the description of various templates in the currently available EPRs and through comparisons with some electronic clinical guidelines. We conclude that TDL is sufficient for the objective but still needs improvement of the algorithm for describing dynamic changes.

Computer Communication Networks↗
PubMed2000

[Five cases of surgically resected chronic expanding hematoma in the chest].

We report surgically treated 5 cases of chronic expanding hematoma in the chest. Three were male and two were female, aged 53 to 76. All patients except one who was thought to have an early stage of chronic expanding hematoma, had severe dyspnea due to compression of lung parenchyma or heart. Complete removal of the hematoma with fibrous capsule was done in two cases, but in three cases the hematoma was removed but the capsule was not because of severe adhesion to the surrounding structures. Post operative course was different to each other. One patient whose capsule was not removed completely have recurrent hematoma in the chest. The pulmonary or cardiac function were improved greatly except for the two cases; an early stage case and a recurrent case. We conclude that surgical removal is the first treatment for chronic expanding hematoma and complete removal of it with capsule is recommended.

Aged↗
PubMed2000

[Validity and controversies in the new postoperative pathologic TNM classification based on the results of surgical treatment of non-small cell lung cancer].

In 1997, the latest revision of the International System for Staging Lung Cancer was published. To validate the new pathologic TNM classification for non-small cell lung cancer (NSCLC), we analyzed the survival data of 455 patients who underwent pulmonary resection and pathologic staging at our institution from January 1980 through December 1999. The overall 5-year survival rate was 51.0%. Using the revised new stage classification, the survival rate for each stage was as follows; IA: 74.2%, IB: 66.4%, IIA: 56.0%, IIB: 51.8%, IIIA: 21.0%, IIIB: 16.0%, and IV: 0%. The current TNM classification well reflected the long-term prognostic hierarchy. There were significant differences in survival rates between patients with stage IA and IB, and between patients with stage IIB and IIIA. However, there was no significant difference between patients with stage IIA and IIB. No significant difference in survival was observed among patients with stage IIIA, stage IIIB, and stage IV. Five-year survival rate of 48.3% in the T3N0M0 category was significantly better than that of 21.0% found in the new stage IIIA. The survival of patients with intrapulmonary metastases in the same lobe (pm1) was not significantly better than that found in the stage IV. The TNM staging system accurately reflects the prognosis in NSCLC, but some stage definitions can be discussed.

Adolescent↗
PubMed2000

[Peripapillary fluorescein angiographic findings in non-glaucomatous eyes].

PURPOSE: In fluorescein angiography (FAG), glaucomatous eyes show a zone of no fluorescence around the disc and hyperfluorescence indicating serum diffusion at the margin of the zone, which play some role in glaucomatous optic nerve damage. But detailed FAG findings have not been reported in non-glaucomatous eyes. We conducted a study to investigate whether peripapillary FAG findings in glaucomatous eyes were specific to glaucoma or not. MATERIALS AND METHODS: 46 eyes of 46 subjects were selected by some reservations from all the non-glaucomatous patients undergoing FAG in 1996. We studied FAG films and measured the zone of no fluorescence adjacent to the disc (non-fluorescent zone). RESULT: 44 eyes (95.6%) showed a non-fluorescent zone. The non-fluorescent zone was clearly wider in temporal sectors than nasal sectors, and its width was related to the refraction. There were two types of non-fluorescent zone, one showing hyperfluorescence from the outer boundary of the zone in the late phase, and the other showing hyperfluorescence from the disc margin. The width of the non-fluorescent zone in the former type was wider than in the latter type. These results are similar to the findings in glaucomatous eyes. CONCLUSION: These findings suggest that not only glaucomatous eyes but also non-glaucomatous eyes have a variety of histological structures and serum diffusion around the disc.

Adolescent↗
PubMed2000

Cytomegalovirus associated pancreatitis in a patient with systemic lupus erythematosus.

Pancreatitis can develop as a complication of systemic lupus erythematosus (SLE). Steroids are considered one of the possible causes of this complication, but the pathological mechanism is unclear. We describe an autopsy case of a 29-year-old woman with cytomegalovirus (CMV) associated pancreatitis that developed during steroid therapy for her SLE. Many parenchymal cells with cytomegalic inclusions were seen in the patient's pancreas, especially in lesions showing active inflammation, and transcripts of CMV major immediate-early and late genes, markers of active viral replication, were detected. These findings suggest that CMV played an etiological role in the pancreatic disorder.

Adult↗
PubMed2000

[A study of reduction of NF 2 protein, mRNA and loss of 22 q in sporadic meningiomas].

Neurofibromatosis 2(NF 2) is one of the tumor suppressor genes, and its disorder has been reported in sporadic meningiomas. We investigated some reduction of expression of NF 2 protein and mRNA in 33 sporadic meningiomas, using immunohistochemistry and in situ hybridization, respectively. Seventeen of 33 (51.5%) meningiomas demonstrated significantly reduced or absent NF 2 protein expression. Its mRNA was also reduced or absent in 11 of 24(45.8%) meningiomas, and some statistically significant correlation was shown between reductions of NF 2 protein and its mRNA. Furthermore, we studied about loss of 22 q in 5 meningiomas with fluorescence in situ hybridization. In the cases with reduction of NF 2 protein and/or mRNA, 22 q telomere signals were observed as loss of heterozygosity. On the other hand, in the cases with expression of NF 2 protein and mRNA, 22 q telomere signals were normal. In conclusion, reduction or absence of NF 2 protein and mRNA may play an important role in the tumorigenesis of about half number of sporadic meningiomas.

Chromosomes, Human, Pair 22↗
PubMed1999

Isolation of a germin-like protein with manganese superoxide dismutase activity from cells of a moss, Barbula unguiculata.

A novel extracellular Mn-superoxide dismutase (SOD) was isolated from a moss, Barbula unguiculata. The SOD was a glycoprotein; the apparent molecular mass of its native form was 120 kDa, as estimated by gel filtration chromatography, and that of its monomer was 22,072 Da, as estimated by time of flight mass spectroscopy. The protein had manganese with a stoichiometry of 0.80 Mn/monomer. The cDNA clone for a gene encoding the extracellular Mn-SOD was isolated. Sequence analysis showed that it has a strong similarity to germin (oxalate oxidase) and germin-like proteins (GLPs) of several plant species and possesses all the characteristic features of members of the germin family. The clone encoding this extracellular Mn-SOD was therefore designated B. unguiculata GLP (BuGLP). BuGLP had no oxalate oxidase activity. In addition, the cDNA for a gene encoding the moss mitochondrial Mn-SOD was isolated. Its amino acid sequence had little similarity to that of BuGLP, even though a close similarity was observed among the mitochondrial Mn-SODs of various organisms. BuGLP was the first germin-like protein that was really demonstrated to be a metalloprotein with Mn-SOD activity but no oxalate oxidase activity.

Amino Acid Sequence↗
PubMed1999

Induction of tumor immunity by removing CD25+CD4+ T cells: a common basis between tumor immunity and autoimmunity.

This study shows that removal of a T cell subpopulation can evoke effective tumor immunity in otherwise nonresponding animals. Elimination of CD25-expressing T cells, which constitute 5-10% of peripheral CD4+ T cells in normal naive mice, elicited potent immune responses to syngeneic tumors in vivo and eradicated them. The responses were mediated by tumor-specific CD8+ CTLs and tumor-nonspecific CD4-8- cytotoxic cells akin to NK cells. Furthermore, in vitro culture of CD25+4+ T cell-depleted splenic cell suspensions prepared from tumor-unsensitized normal mice led to spontaneous generation of similar CD4-8- cytotoxic cells capable of killing a broad spectrum of tumors; reconstitution of CD25+4+ T cells inhibited the generation. In this culture, self-reactive CD25-4+ T cells responding to self peptides/class II MHC complexes on APCs spontaneously proliferated upon removal of CD25+4+ T cells, secreting large amounts of IL-2. The IL-2 thus produced appeared to be responsible for the generation of CD4-8- NK cells as lymphokine-activated killer cells, because direct addition of an equivalent amount of IL-2 to the culture of CD4-8- cells generated similar lymphokine-activated killer/NK cells, whereas coculture of normal CD4-8- cells with CD25-4+ T cells from IL-2-deficient mice did not. Thus, removal of immunoregulatory CD25+4+ T cells can abrogate immunological unresponsiveness to syngeneic tumors in vivo and in vitro, leading to spontaneous development of tumor-specific effector cells as well as tumor-nonspecific ones. This novel way of evoking tumor immunity would help to devise effective immunotherapy for cancer in humans.

Animals↗
PubMed1999

Cholesterol 7-hydroperoxides in rat skin as a marker for lipid peroxidation.

Concentrations of cholesterol 7alpha- and 7beta-hydroperoxides (Ch 7-OOHs) in the skin of rats were determined by HPLC with a chemiluminescence detector. We demonstrated that (a) the concentrations of Ch 7-OOHs in rat skin were highly correlated with rat age (r = 0.929; N = 51, 1 to 55 weeks old), (b) the concentrations of Ch 7-OOHs in the skin of rats in an ambient light room were not significantly different from those found in rats kept in a dark room for 12 weeks, and (c) lipid peroxidation in vitro induced by ADP-Fe2+ caused an increase in the concentrations of Ch 7-OOHs in homogenates of rat skin. These results indicated that levels of Ch 7-OOHs in skin might be a good marker for aging of rats and might be independent of housing illumination, thus a good marker for endogenous lipid peroxidation. Furthermore, we observed that ultraviolet light B (UVB) irradiation markedly enhanced the concentrations of Ch 7-OOHs in the skin of rats in vivo depending on the duration of the irradiation, and the increases in Ch 7-OOHs were inhibited by radical scavengers, i.e. tocopherols. Therefore, it was suggested that the levels of Ch 7-OOHs in the skin could also be a good marker for UVB-dependent lipid peroxidation.

Adenosine Diphosphate↗