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H Shimada

Publications and source records attributed to H Shimada.

At least 523 records · Page 29Linked to original sources
PubMed1994

Agreement among and within groups of pathologists in the classification of rhabdomyosarcoma and related childhood sarcomas. Report of an international study of four pathology classifications.

BACKGROUND: An International Pathology study was conducted to measure the agreement demonstrated among and within groups of pathologists involved in the categorization of childhood rhabdomyosarcoma according to four pathology classifications. Data concerning agreement and survival experience according to patho-new subtypes were used as a basis for selection of a proposed new pathologic classification. METHODS: A random sample of 800 eligible patients was chosen from the Intergroup Rhabdomyosarcoma Study II (IRS-II) and was reviewed by pathologists representing eight institutions. A 20% sample of the 800 patients was then reviewed by the pathologists to determine the level of agreement with their original classification. In each instance the patients were classified according to four pathology systems: the conventional system, the International Society for Pediatric Oncology system (SIOP), the National Cancer Institute (NCI) system, and the cytohistologic system. RESULTS: Among the groups of pathologists, the highest measure of agreement was a Kappa value of K = 0.451 for the conventional system, followed by K = 0.406 for the SIOP system, K = 0.384 for the NCI system, and K = 0.328 for the cytohistologic system. For reproducibility within the groups of pathologists, the highest measure of agreement was K = 0.605 for the conventional system, followed by K = 0.579 for the NCI system, K = 0.573 for the SIOP system, and K = 0.508 for the cytohistologic system. CONCLUSIONS: There was a general similarity between the agreement reached within the modified conventional, STOP, and NCI systems, with the modified conventional system having the highest Kappa values, and thus the highest measure of agreement, both among and within the groups of pathologists. Also, the subtypes of the conventional system demonstrated a highly significant relationship to survival time. Hence, based on criteria of reproducibilty and prognostic significance, the proposed classification will essentially be a modification of the conventional system with elements of the SIOP and NCI systems.

Adolescent↗
PubMed1994

Prevalence of serum and salivary antibodies to HTLV-1 in Sjögren's syndrome.

There is accumulating evidence that human T-lymphotropic virus-1 (HTLV-1) infection contributes to the development of various inflammatory disorders. To elucidate the relation between the infection and Sjögren's syndrome, seroepidemiological and virological studies were conducted on patients with this syndrome in Nagasaki Prefecture, Japan, an area heavily endemic for HTLV-1. The HTLV-1 seroprevalence rate among the patients with Sjögren's syndrome (17/74, 23%) was significantly higher than that among blood donors (916/27,284, 3%), whereas the difference between patients with systemic lupus erythematosus and blood donors was insignificant. Moreover, among Sjögren's syndrome patients the seroprevalence was high irrespective of age, unlike that among blood donors, which rose with age. Titres of serum antibodies in the HTLV-1 seropositive patients with Sjögren's syndrome were similar to those among patients with HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) and significantly higher than those among healthy carriers. IgM class antibodies were commonly detected in the serum of patients with Sjögren's syndrome. However, unlike that in HAM/TSP patients, the viral load in peripheral-blood mononuclear cells was not necessarily high in the seropositive Sjögren syndrome group. Salivary IgA antibodies to HTLV-1 were common among seropositive patients with Sjögren's syndrome (5/7), which might be due to increased viral activity in the salivary glands. These antibodies were barely detectable in HAM/TSP patients (prevalence 1/10) or in healthy carriers (0/11). The findings strongly suggest that HTLV-1 is involved in the pathogenesis of the disease in a subset of patients with Sjögren's syndrome in endemic areas.

Adolescent↗
PubMed1994

Evidence for compound I formation in the reaction of cytochrome P450cam with m-chloroperbenzoic acid.

During the reaction of m-chloroperbenzoate with low spin ferric form of cytochrome P450cam, the formation of at least four transient intermediates was detected by employing rapid scan absorption spectrometry. Among them, the first one which appeared within 10 msec after the start of reaction gave an absorption spectrum indistinguishable from that of compound I of chloroperoxidase, another thiolate-heme protein. The intermediate exhibited the major absorption maxima at 367 and 694 nm, while chloroperoxidase compound I is known to have the maxima at 367 and 688 nm. The shapes of the bands at 367 nm were very similar to each other. Based on these spectral similarities, we suggest that the intermediate found in this study is the compound I of cytochrome P450cam.

Camphor 5-Monooxygenase↗
PubMed1994

Comparative effects of chelating agents on distribution, excretion, and renal toxicity of gold sodium thiomalate in rats.

The effects of various chelating agents, such as (2S)-1-(3-mercaptopropionyl)-L-proline (captopril), N-(2-mercaptopropionyl)-glycine (tiopronin), L-cysteine (L-Cys), D-cysteine (D-Cys), N-acetyl-L-cysteine (L-NAC), N-benzyl-D-glucamine dithiocarbamate (BGD), and ethylenediaminetetraacetate (EDTA), on the distribution, excretion, and renal toxicity of gold sodium thiomalate (AuTM) in rats were investigated. Rats were intraperitoneally injected with the chelating agents (1.2 mmol/kg each) immediately after intravenous injection of AuTM (0.026 mmol/kg). Treatment with captopril or tiopronin significantly prevented increases in the urinary excretion of protein, aspartate aminotransferase (AST), and glucose and the blood urea nitrogen (BUN) level after AuTM injection. L-NAC and D-Cys significantly prevented increases in the urinary excretion of protein, AST, and glucose after AuTM injection, but did not reduce to control levels. Treatment with BGD, EDTA, or L-Cys did not prevent AuTM-induced increases in the urinary excretion of protein, AST, and glucose and BUN level. Tiopronin significantly increased the urinary excretion of gold. Captopril slightly promoted both the urinary and fecal excretion of gold, resulting in the significant increase in the total excretion of the metal. Tiopronin and captopril significantly decreased the gold concentration in the kidney and liver. L-Cys, D-Cys, L-NAC, BGD, and EDTA had no significant effect on the excretion or distribution of gold at 7 days after AuTM injection. These results indicate that tiopronin and captopril can ameliorate the renal toxicity induced by AuTM. In addition, the comparative effects of 2,3-dimercaptopropane sulfonate (DMPS), N-(2-mercapto-2-methylpropanoyl)-L-cysteine (bucillamine), captopril, and tiopronin at various dose levels (1.2, 0.4 or 0.2 mmol/kg) on the distribution and renal toxicity of gold were studied. DMPS was effective in removing gold from the kidney and in protecting against the renal toxicity after AuTM injection at the even lower dose level (0.2 mmol/kg). Bucillamine and tiopronin protected against the renal toxicity of gold at dose levels of 0.4 and 1.2 mmol/kg and captopril ameliorated the gold toxicity only at higher dose level (1.2 mmol/kg).

Animals↗
PubMed1994

Mechanism of mobilization of renal and hepatic cadmium by dithiocarbamates in mice.

To clarify the mechanism of mobilization of renal and hepatic cadmium (Cd) by N-benzyl-D-glucamine dithiocarbamate (BGD) and N-p-hydroxymethylbenzyl-D-glucamine dithiocarbamate (HBGD) in mice exposed to Cd, the effects of pretreatment with probenecid, an organic anion transport inhibitor, or with acivicin, a gamma-glutamyltranspeptidase (gamma-GTP) inhibitor and ureter-ligation were investigated on the excretion and distribution of chelating agents and Cd. The renal contents of BGD and HBGD were increased by ureter-ligation and decreased by acivicin pretreatment. The mobilizing effect of BGD on the renal Cd was inhibited by probenecid pretreatment. The action of HBGD in removing Cd from the kidney was inhibited by both probenecid pretreatment and ureter-ligation. These results suggest that BGD and HBGD are mainly taken up into the renal tubular cells through the basolateral membrane which is dependent on the action of gamma-GTP; that the Cd-BGD complex formed in the tubular cells is secreted by a probenecid-sensitive organic anion transport system through the basolateral membrane; and that the Cd-HBGD complex formed in the tubular cells is secreted to the tubular lumen by an organic anion transport system through the brush border membrane. Probenecid pretreatment increased the hepatic contents of BGD and HBGD and also promoted the effects of these chelating agents in removing Cd from the liver, indicating an inhibitory effect of probenecid on the glucuronidation of BGD and the secretion of HBGD from the kidney. These results suggest that BGD and HBGD are taken up into the liver and secreted from the organ to the bile by a transport system other than a probenecid-sensitive transport mechanism.

Animals↗
PubMed1994

Determination of carbenicillin epimers in plasma and urine with high-performance liquid chromatography.

A high-performance liquid chromatographic method was developed for determining the concentrations of carbenicillin (CBPC) epimers in plasma and urine. Samples were prepared for HPLC analysis by solid-phase extraction and the concentrations of CBPC epimers were determined using reversed-phase HPLC with a mixture of 0.05 M ammonium acetate and methanol as a mobile phase. Baseline separation of the two epimers was observed for both plasma and urine samples with a detection limit of ca. 10 micrograms/ml. No peaks interfering with either of the CBPC epimers were observed on the HPLC chromatograms for blank plasma and urine. The presented method was used to determine the protein binding of CBPC epimers in vitro in human and rabbit plasma. The stereoselectivity of the binding of CBPC appeared to be reversed in human and rabbit plasma.

Adult↗
PubMed1994

Papovavirus detection by electron microscopy in the brain of an elderly patient without overt progressive multifocal leukoencephalopathy.

Virions resembling papovavirus were demonstrated in glial cells in the brain of an aged patient without overt progressive multifocal leukoencephalopathy. The patient was not in a severely immunocompromised state. On histological examination, only a few tiny incomplete necrotic foci were found in the subcortical area. These foci were widely dispersed. Rare, swollen oligodendroglial cells and astrocytes in which papovavirus capsid protein (VP-1) was demonstrated immunohistochemically were present around the foci. The two typical types of virus particles i.e. 35 to 40 nm round particles and elongated particles, were observed in the nuclei of the swollen glial cells. The latter were in the minority. Distinct crystals were also found in the nuclei. The centre-to-centre distance of the particles in the crystals, about 40 nm, and the electron-opaque spots of the round-shaped virions and of the elongated particles, were indicative of structural subunits of papovavirus capsids. This case provides further evidence that papovavirus, possibly JC virus, may be reactivated in the brains of aged patients who are not in an immunocompromised state.

Aged↗
PubMed1994

Ca(2+)-dependent unidirectional vesicular release detected with a carbon-fibre electrode in rat pancreatic acinar cell triplets.

An amperometric constant-voltage method for detection of serotonin oxidation currents was applied to pancreatic acinar cell triplets to determine the site of release of granular content following an increase in [Ca2+]i. The carbon fibre electrode, fabricated to be compatible with a conventional patch-clamp amplifier, was voltage-clamped at 600 mV exceeding the serotonin oxidation voltage, 300 mV. The electrode was placed on the different regions of cell surface of acinar cell triplets loaded with exogenous serotonin. Transient oxidation currents were detected only when the electrode was placed on the acinar lumen after stimulation with a Ca2+ ionophore, A23187, but never observed on the basal or lateral cell surface, or paracellular clefts. No such current responses were observed in the acinar cells without serotonin loading. The results indicate that the A23187-induced sustained increase in [Ca2+]i discharges serotonin specifically into the lumen, and provides direct evidence for the presence of Ca(2+)-dependent unidirectional release of granular contents in pancreatic acinar cells.

Animals↗
PubMed1994

A unique sequence located downstream from the rice mitochondrial atp6 may cause male sterility.

Asymmetric cell-fusion of the japonica cultivar of Oryza sativa (rice) with cytoplasmic-male-sterile (CMS) plants bearing cytoplasm derived from Chinsurah Boro II, resulted in two classes of cytoplasmic hybrids (cybrids), fertile and CMS. Southern-blot analysis of the mitochondrial DNA (mtDNA) indicates recombination events around a number of genes; however, the appearance of the CMS character is tightly correlated to reorganization around the atp6 gene, suggesting recombination downstream from the atp6 gene is involved in CMS. The nucleotide sequence downstream from atp6 contains a pseudogene which was probably created by recombination of the mitochondrial genome. Sense and antisense transcripts of the downstream region of atp6 were found in CMS- and restored CMS (fertile)-lines, but not in the normal (fertile) line. In the CMS line, several antisense transcripts of the atp6 gene were also found. However, in the restored line which contains a nuclear-encoded gene, Rf-1, the levels of these transcripts were lower than in the CMS line. These results suggest abnormal transcripts of the atp6 gene produced in the antisense direction may be involved in CMS, and that products of the nuclear-encoded restorer gene may reduce abnormal transcription in this region of the mitochondrial genome.

Base Sequence↗
PubMed1994

Tumoral invasion in the central nervous system.

During growth, migration and differentiation, cells closely interact with the extracellular matrix (ECM). The harmony between cells and their environment is a key factor that maintains the normal architecture of tissues. Loss of growth control is not the only characteristic of oncogenesis, loss of control by the ECM is an important event that allows malignant cells to further progress toward invasion and metastasis. Changes in cell adhesion, proteolytic degradation of the ECM and cell migration have all been described during invasion of most tissues by tumor cells. However little is known of these changes in tumors of the central nervous system (CNS). Although brain tumor cells may share some of the invasive characteristics of tumors that arise outside the CNS, the particular structure and composition of the brain ECM suggest the existence of unique invasive mechanisms in these tumors. Furthermore, the interaction between brain tumor cells and their ECM may explain the intriguing observation that despite their highly invasive behavior, these cells remain poorly metastatic. This review focuses on biochemical mechanisms essential for tumor invasion and how they relate to invasion of tumors that arise in the CNS.

Animals↗
PubMed1994

Antroduodenal motility and transpyloric fluid movement in patients with diabetes studied using duplex sonography.

BACKGROUND/AIMS: To elucidate the relationship between diabetic autonomic neuropathy and gastrointestinal motility, antroduodenal motility was studied in patients with diabetes using duplex sonography. METHODS: Antroduodenal motility, transpyloric fluid movement, and velocity curves of fluid flow were studied using duplex sonography in 32 patients with diabetes and 10 healthy subjects after their ingestion of a meat soup. RESULTS: The frequency of antroduodenal coordination was significantly reduced in patients with diabetes with both early and definite autonomic neuropathy compared with healthy subjects (P < 0.05 and P < 0.01, respectively). The frequency and duration of end-cycle reflux episodes were also significantly reduced in patients with early and definite autonomic neuropathy compared with healthy subjects (P < 0.05 and P < 0.01, respectively). The frequency of end-cycle reflux episodes was closely correlated with the frequency of antroduodenal coordination in both healthy subjects (r = 0.859; P = 0.002) and patients with diabetes (r = 0.929; P = 0.0001). There was a significant correlation between fasting plasma glucose concentrations and the frequency of antroduodenal coordination in patients with diabetes (r = -0.361; P = 0.039). CONCLUSIONS: These findings suggest that reduced frequency and duration of end-cycle reflux episodes may be an early indicator of diabetic gastroparesis that may be related mainly to autonomic neuropathy but also in part to acute hyperglycemia.

Adult↗
PubMed1994

Distorted microangioarchitecture and impaired angiogenesis in gastric mucosa of portal hypertensive rats.

BACKGROUND/AIMS: Portal hypertensive (PHT) gastropathy is now recognized as a distinct entity, but the size of microvessels has been a subject of controversy. Angiogenesis in PHT gastric mucosa has not been explored. The aim of this study was to examine the angioarchitecture of PHT and non-PHT gastric mucosae before and after ethanol-induced injury utilizing microvascular cast techniques. METHODS: Portal hypertension was produced by staged portal vein occlusion. Fourteen days later, gastric vascular casts were made in both PHT and control (sham-operated) rats by Mercox resin infusion. After tissue dissolution, casts were examined under a scanning electron microscope. To examine angiogenesis in injured gastric mucosa, the above study was repeated in PHT and control rats 18 hours after intragastric administration of 100% ethanol. RESULTS: The capillary casts in PHT gastric mucosa (mean diameter, 6.3 +/- 0.03 microns) were significantly narrower than those of controls (mean diameter, 8.6 +/- 0.02 microns; P < 0.01). After ethanol injury, 5.5% +/- 0.3% of microvessels in gastric mucosa of sham-operated rats contained buds, showing angiogenesis. In contrast, PHT gastric mucosa had a paucity of capillary angiogenesis (buds in only 0.4% +/- 0.2% of microvessels; P < 0.01 vs. control). CONCLUSIONS: This study shows prominent persistent abnormalities in the microangioarchitecture of PHT gastric mucosa. Moreover, PHT gastric mucosal microvessels have a marked impairment of angiogenic response to ethanol injury.

Animals↗
PubMed1994

In vivo rodent erythrocyte micronucleus assay.

The following summary represents a consensus of the working group except where noted. The items discussed are listed in the order in which they appear in the OECD guideline (474) for easy reference. Introduction, purpose, scope, relevance, application and limits of test. The analysis of immature erythrocytes in either bone marrow or peripheral blood is equally acceptable for those species in which the spleen does not remove micronucleated erythrocytes. In the mouse, mature erythrocytes are also an acceptable cell population for micronucleus analysis when the exposure duration exceeds 4 weeks. Test substances. Organic solvents such as DMSO are not recommended. Freshly prepared solutions or suspensions should be used unless stability data demonstrate the acceptability of storage. Vegetable oils are acceptable as solvents or vehicles. Suspension of the test chemicals is acceptable for p.o. or i.p. administration but not for i.v. injection. The use of any unusual solvent should be justified. Selection of species. Any commonly used laboratory rodent species is acceptable. There is no strain preference. Number and sex. The size of experiment (i.e., number of cells per animal, number of animals per group) should be finalized based on statistical considerations. Although a consensus was not achieved, operationally it was agreed that 2000 cells per animal and four animals per group was a minimum requirement. In general, the available database suggests that the use of one gender is adequate for screening. However, if there is evidence indicating a significant difference in the toxicity between male and female, then both sexes should be used. Treatment schedule. No unique treatment schedule can be recommended. Results from extended dose regimens are acceptable as long as positive. For negative studies, toxicity should be demonstrated or the limit dose should be used, and dosing continued until sampling. Dose levels. At least three dose levels separated by a factor between 2 and square root of 10 should be used. The highest dose tested should be the maximum tolerated dose based on mortality, bone marrow cell toxicity, or clinical symptoms of toxicity. The limit dose is 2 g/kg/day for treatment periods of 14 days or less and 1 g/kg/day for treatment periods greater than 14 days. A single dose level (the limit dose) is acceptable if there is no evidence of toxicity. Controls. Concurrent solvent (vehicle) controls should be included at all sampling times. A pretreatment sample, however, may also be acceptable only in the short treatment period peripheral blood studies. A concurrent positive control group should be included for each experiment.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1994

Novel immunoaffinity extraction for liquid chromatographic determination of major metabolites of 4-acetoxy-2-(4-methylphenyl)benzothiazole in plasma.

Group extraction of the metabolites of 4-acetoxy-2-(4-methylphenyl)benzothiazole has been achieved through the use of an immunoaffinity adsorbent. The antisera elicited from an immunogen, 4-hydroxy-2-(4-formylphenyl)benzothiazole O-carboxymethyloxime-bovine serum albumin conjugate, were characterized to have a broad affinity spectrum for major metabolites oxidized at the 4-methyl group of the benzene moiety. One millilitre of the immunoaffinity adsorbent prepared by immobilization of antibodies (12.5 mg ml-1) was capable of retaining up to 4 micrograms of benzothiazoles. The adsorbates were recovered quantitatively by elution with 90% (v/v) methanol without any interfering peaks on the high-performance liquid chromatogram. The peak-height ratio of each metabolite to an internal standard was plotted against the concentration of the former substance; good linearity was observed in the range of 10-500 ng ml-1.

Animals↗
PubMed1994

A serosa-searing apparatus for producing gastric ulcer in rats.

Chronic ulcer models produced by serosa-searing method are very similar histologically to the ulcer healing process occurring in humans. In an effort to produce a serosa-searing chronic ulcer model in rats, we devised a new balance-type apparatus. This searing apparatus is capable of changing adequately both temperature and duration of time. Furthermore, the pressure which serves to bring the searing iron tip into contact with the stomach serosa surface can also be precisely changed. Optimal conditions for reproducing the serosa-searing ulcer model were at 65 degrees C and in 5 sec. Moreover, in order to evaluate the effects of pressure, various pressure levels (A: 5 g, 17.68 g/cm2; B: 10 g, 35.37 g/cm2; C: 15 g, 53.05 g/cm2; D: 20 g, 70.74 g/cm2; E: 25 g, 88.42 g/cm2; F: 30 g, 106.10 g/cm2; G: 35 g, 123.79 g/cm2 (+/- 1 g, 0.149 g/cm2)) of 5-sec duration at 65 +/- 0.1 degrees C were used. Macroscopically, gastric mucosal lesions were most clearly observed in a pressure-related manner 7 days after the procedure. Histologically, definite deep ulcerations (UI-III or UI-IV) were observed at pressure level C (15 g, 53.05 g/cm2) or more. The highest incidence (87%) of histological gastric ulcers (UI-IV) was observed in pressure level E (25 g, 88.42 g/cm2). The healing process was observed at 40 to 60 days postoperatively. At 100 days after the procedure, recurrences were observed both macroscopically and histologically. In conclusion, this new apparatus is very useful for reproducing a chronic ulcer model for observing the healing and recurrence process.

Animals↗
PubMed1994

Vitrectomy for diabetic macular heterotopia.

PURPOSE: The authors performed 15 vitrectomies for diabetic macular heterotopia, and then compared visual prognoses and postoperative complications with those of 88 macular detachments to determine the role of, and indications for, vitrectomy for diabetic macular heterotopia. METHODS: Fifteen patients with diabetic macular heterotopia and 88 with traction macular detachment, in which the vitreous cavities were sufficiently clear for posterior poles to be observed, underwent vitrectomies. Preoperative and postoperative visual acuity and postoperative complications were assessed and documented retrospectively. RESULTS: There was no statistically significant difference between the two groups in terms of eyes showing improvement in visual acuity postoperatively. However, a final postoperative visual acuity better than 20/20 was documented in 93% of patients with macular heterotopia and 48% of patients with macular detachment (P < 0.002), whereas 47% of the former and 10% of the latter had visual acuities better than 20/40 (P < 0.001). Postoperative neovascular glaucoma and retinal detachment developed in 10% and 13%, respectively, of patients with macular detachments. None of the patients with macular heterotopia experienced these complications. CONCLUSION: Based on the above results, the authors conclude that diabetic macular heterotopia is a very good indication for early vitrectomy.

Adult↗