Biomedical subjects

S Ishiguro

Publications and source records attributed to S Ishiguro.

At least 145 records · Page 8Linked to original sources

PubMed1996

Correlation of age-adjusted incidence and age-adjusted death rate in colorectal cancer among municipalities in Aomori Prefecture.

To clarify to what extent death rate reflects the incidence of colorectal cancer, we calculated the age-adjusted death rates for colorectal cancer among municipalities in Aomori Prefecture for the period between 1983 and 1987, and examined the correlation with the age-adjusted incidences of the disease during different 5-year periods. In males, the age-adjusted death rate of rectal or colon cancer most correlated with the age-adjusted incidence in the preceding period by three or two years, respectively; however in females, the age-adjusted death rate best reflected the age-adjusted incidence of the same period. In males, significant correlation was lost if the interval exceeded seven years in both rectal and colon carcinomas. In females, the correlation became insignificant after an interval of four and five years in rectal and colon cancers, respectively.

Adult↗

PubMed1996

Postnatal developmental expression of glutamine and related amino acids in the rat retinas.

PURPOSE: To evaluate postnatal developmental changes in the amounts of retinal glutamate, glutamine and GABA, and in the distribution of retinal glutamine in the rat. METHODS: Free amino acids were extracted from rat retinas of different postnatal stages, and the concentrations of glutamate, glutamine and GABA were determined by HPLC. Also, anti-glutamine antibody was raised and an immunocytochemistry was performed with paraffin-embedded retinal sections in parallel with free amino acid analyses. RESULTS: Glutamate occurred in high concentrations at the birth and showed a stable pool, while glutamine and GABA remained low until postnatal day 3 or 5, and gradually increased in the developing rat retinas. Glutamine immunolabeling was observed in the retinal pigment epithelium and in a subpopulation of presumed amacrine cells in the early postnatal days. It was also found in Muller cells and in some ganglion cells or displaced amacrine cells in the ganglion cells layer. Glutamine immunolabeling was transiently observed also in horizontal cells. Finally, the immunolabeling was dominant in the inner and outer plexiform layers in the adult retinas. CONCLUSIONS: Postnatal developmental increase in the levels of glutamine and GABA might be dependent on the maturation of neurons or glial cells that possess the activity of the key enzymes of each amino acid. It was suggested that an expression of glutamine immunolabeling can be a marker of neurons that utilize glutamine as a precursor for glutamate or GABA, and of Müller cell maturations in postnatal early stage of the retina, while it changes to demonstrate the locations of glutamine cycle in the retina with adult characteristics.

Animals↗

PubMed1996

Changes in GABA metabolism in streptozotocin-induced diabetic rat retinas.

We examined the pathogenesis of reduced amplitude in electroretinogram (ERG) oscillatory potentials (OPs) in diabetes, in relation to possible changes in the metabolisms involving retinal amino acid neurotransmitters. With use of streptozotocin diabetic rats, flash ERGs were recorded and quantitative analyses of retinal free amino acids were performed. Immunocytochemical localizations of retinal glycine and GABA were examined. In addition, activities of glutamic acid decarboxylase (GAD) and GABA transaminase (GABA-T) were measured. Our results revealed that the amplitudes of OP 1 and OP 2 decreased, and retinal glycine and GABA content significantly increased in the diabetic rats. An increased immunoreactivity of GABA was observed in Müller cells in the diabetic rat retinas, while no apparent changes were found in glycine immunoreactivity. Finally, increased activations of GAD with reduced activities of GABA-T were observed in the diabetic rat retinas. Thus, reduced amplitudes of OPs were associated with changes in content, localization, and enzyme activities related to GABA in the retinas, implying that changes in GABA metabolism can be a candidate for the pathogenesis of the abnormal OPs in diabetes.

4-Aminobutyrate Transaminase↗

PubMed1996

Localization of proline-like immunoreactivity in young rat retinal neurons.

PURPOSE: To localize proline in the rat retina. METHOD: We prepared antibodies raised against proline coupled to bovine serum albumin (BSA) with glutaraldehyde. To confirm the specificity of the antiserum, crossreactivity with other amino acids was determined using an immunodot procedure. Rat eyes were enucleated on postnatal day 21. Immunohistochemistry was performed on semi-thin sections using gold-labelled secondary antibodies and a silver-enhancement technique. RESULTS: Immunodots revealed that the antiserum was specific for proline. Amino acids from retinal extracts were separated on gel, transferred to BSA-glutaraldehyde treated filters, and stained with antibodies to determine if our antibody reacted only with proline. Staining was most intense on postnatal day 21 and disappeared in the adult retina. In addition to Muller cells, horizontal cells, amacrine cells, and some cells in the ganglion cell layer were labelled. CONCLUSIONS: Antibodies raised against proline revealed a transient immunoreactivity in young rat neurons. Our findings strongly indicate that the retina may express a high level of proline in the developmental stages. This result may provide a clue for clarifying the role of proline in the retina.

Animals↗

PubMed1996

Accumulation of gamma-aminobutyric acid in diabetic rat retinal Müller cells evidenced by electron microscopic immunocytochemistry.

PURPOSE: To evaluate possible changes in the distribution of gamma-aminobutyric acid (GABA) in diabetic rat retinas. METHODS: GABA distributions in the normal control and diabetic rat retinas were determined by a quantitative immunogold electron microscopic immunocytochemistry with anti-GABA antibody. GABA immunoreactivities (GABA-IR) in the retinas were visualized as bound gold colloidal particles in electron microscopy, and the average densities were calculated in each layer or in each kind of cells. The amounts of GABA-IR were statistically compared between normal control and diabetic rat retinas. RESULTS: In the normal control rat retinas, the amounts of GABA-IR was most abundant in the inner portion of the inner nuclear layer, followed by the inner plexiform layer. GABA-IR in amacrine cells ranged from the background level to the highest throughout the retina. Although the distribution pattern of GABA-IR in the diabetic rat retinas was similar to that of the normal control, GABA-IR increased significantly in the inner segment, the outer nuclear layer, and the outer plexiform layer (P < 0.05, by the analysis of variance), and in Müller cells (P < 0.001, by Mann-Whitney's U-test) of the diabetic rat retinas. However, pathologic accumulation of GABA-IR was not demonstrated in amacrine cells of the diabetic rat retinas. CONCLUSIONS: These results supported the accumulation of GABA in diabetic rat retinal Müller cells evidenced by light microscopic immunocytochemistry previously. It was suggested that GABA accumulation represents one of the functional deterioration of Müller cells in diabetic rat retinas.

Animals↗

PubMed1996

[A report of surgical treatment for atherosclerotic aneurysm in the aortic arch associated with type III acute aortic dissection].

A 75-year-old man was admitted to our hospital because of severe chest pain. A chest CT scan demonstrated an atherosclerotic true aneurysm measuring 50 mm in diameter located just distal to the aortic arch as well as a DeBakey type III dissection. Although the patient received medical therapy, the size of the true aortic aneurysm increased to 71 mm and the false lumen of the descending aorta was also enlarged after three weeks. At 11 weeks after admission, the aortic arch and the proximal portion of the descending aorta were replaced with a 32 mm Hemashield graft using moderate hypothermic selective cerebral perfusion. The postoperative course was uneventful, and there were no neurological complications. Coexistence of atherosclerotic true aneurysm and acute aortic dissection appears to increase the risk of aortic rupture, early surgical treatment should be considered.

Acute Disease↗

PubMed1996

Light-evoked changes of glycine-like immunoreactivity in the rat retina.

Glycine is an important inhibitory neurotransmitter in the vertebrate retina. Although many reports of glycine localization by the immunocytochemical method have been published, none has distinguished the neurotransmitter function of glycine from metabolic change. If glycine is the neurotransmitter, it seems that it must be affected or released by stimulation. We evaluated the possibility that glycine in retinal synapses changes with light stimulation. Glycine-like immunoreactivity was found by light microscopy to be present mainly in the inner plexiform layer and amacrine cells. In the inner plexiform layer these immunoreactive products decreased after illumination. The distribution of glycine-like immunoreactivity in the rat retina was also investigated after embedding anti-rabbit IgG-gold colloidal particles (GCP). In the dark-adapted eyes, glycine-like immunoreactivity was marked in the inner plexiform layer (27.8 +/- 5.7 GCP/microns2) and amacrine cells (33.5 +/- 5.5 GCP/microns2). This immunoreactive product significantly decreased only in the inner plexiform layer after illumination (15.5 +/- 4.5 GCP/microns2). These changes in immunoreactivity may reflect the release of endogenous glycine. Our results provide evidence for the role of glycine as a retinal neurotransmitter.

Animals↗

PubMed1996

[A case report of surgical treatment for acute mitral insufficiency associated with acute gastric lesion].

A 76-year-old female was admitted to our hospital due to anterior chest pain and dyspnea. Mitral regurgitation due to prolapse of the posterior leaflet was detected by UCG. After admission, massive gastric hemorrhage was observed. Because hemostatic therapy using endoscopy was not effective, partial gastrectomy was performed. The origin of the hemorrhage, an acute gastric ulcer, was located on the side of the minor curvature of the corpus ventriculi. After gastrectomy, the patient underwent medical treatment using an IABP, but the left heart failure was not reduced, and the pulmonary edema worsened. At 18 hours after gastrectomy, MVR was performed. The cause of regurgitation is torn chordae of the posterior leaflet. The postoperative course was good, and the patient is doing well in NYHA class 1. This case is the first report of acute mitral insufficiency associated with acute gastric lesion in Japan.

Acute Disease↗

PubMed1996

Diagnosis of pancreatic cancer by K-ras point mutation and cytology of pancreatic juice.

OBJECTIVES: Recently, it was reported that detection of K-ras point mutation at codon 12 in pancreatic juice is an objective method for the diagnosis of pancreatic cancer, but a few reports have suggested that this might represent an early event in pancreatic oncogenesis. In the present study we examined, in various patients, the occurrence of K-ras codon 12 point mutation in pancreatic juice and compared it with pancreatic juice cytology, which is also a reliable diagnostic method. METHODS: Pancreatic juice was obtained endoscopically from patients with various pancreatic disorders and those without definite diseases, and was examined cytologically and for the occurrence of K-ras codon 12 point mutation. The K-ras gene was amplified by polymerase chain reaction (PCR) and the mutation at codon 12 (GGT-->GAT) was examined by slot blot hybridization analysis. RESULTS: K-ras point mutation at codon 12 was detected in seven of 14 (50%) pancreatic cancers, in four of 10 (40%) mucin-producing tumors, in four of 13 (31%) chronic pancreatitis, and in two of 10 (20%) pancreas without definite disorders. K-ras point mutation was detected in nine of 18 (50%) pancreatic juice samples containing cancer cells, in eight of 18 (44%) pancreatic juice samples containing atypical cells, but in none of such samples containing only normal cells. CONCLUSION: Cancer cells were detected from pancreatic cancer exclusively, but K-ras point mutation at codon 12 was detected in pancreatic juice, not only from pancreatic cancer, but also from other diseases.

Aged↗

PubMed1996

[Partial purification of endogenous growth factor(s) of retinal pigment epithelial cells from neural retina].

We attempted to purify endogenous growth factors of chick embryonal retinal pigment epithelial cells from bovine neural retina. Ammonium sulfate precipitation, gel filtration, and anion exchange column chromatography were used. Though only partially purification, bovine retinal extract had two effects, growth and transformation, on chick embryonal pigment epithelial cells. We think that these purified factors may be novel from the estimation of their molecular weight by gel filtration.

Animals↗

PubMed1996

MR of xanthogranuloma of the choroid plexus.

We present a case of a xanthogranuloma of the lateral ventricle choroid plexus in association with focal areas of abnormal T2 signal in the tegmentum of the pons as well as within the middle cerebellar peduncles. The characteristic MR appearance of this rare entity is described along with a pathologic basis suggesting an association with posterior fossa lesions.

Adult↗

PubMed1996

[A case report of Stanford type A acute thrombosed aortic dissection complicating cardiac tamponade].

An 85-year-old man was admitted with shock due to cardiac tamponade. Plain computed tomography showed a dilated ascending aorta but did not clearly show an aortic dissection. We performed an emergency operation with median sternotomy without the benefit of findings from enhanced computed tomography and aortography. Soon after the bloody pericardial effusion was decompressed during the operation, bleeding from the ascending aorta occurred. An intimal tear was found in the distal ascending aorta, and the pseudolumen was filled with fresh thrombus. The ascending aorta was replaced. The patient had an uneventful postoperative recovery and was discharged 1 month after the operation. We conclude that patients with Stanford type A acute thrombosed aortic dissection complicating cardiac tamponade should undergo early graft replacement.

Acute Disease↗

PubMed1996

[Usefulness of spiral CT in the detection of hypovascular, well-differentiated hepatocellular carcinoma].

Whole liver scanning during artery-dominant phase using spiral CT was performed in 14 patients with 17 histologically proven well-differentiated HCCs, which were not depicted by hepatic digital subtraction angiography but by CT during arterial portography. The density of HCC relative to the liver was evaluated with conventional precontrast CT, spiral CT, and following conventional CT during the equilibrium phase. Comparison between spiral CT and magnetic resonance (MR) imaging of dynamic contrast studies was also investigated. Four tumors of 17 HCCs (24%) were shown as a high-density area by the artery-dominant phase using spiral CT. Consequently, the total sensitivity of these three kinds of CT techniques was elevated to 82%. The sensitivity of dynamic MR imaging was slightly greater than that of spiral CT. However, spiral CT sometimes made the diagnosis more conspicuous by it's good spatial resolution. Our results indicate that spiral CT has a potential benefit in the detection of hypovascular well-differentiated HCC, and MR imaging and spiral CT may be complement each other.

Aged↗

PubMed1995

Involvement of thromboxane A2-thromboxane A2 receptor system of the hepatic sinusoid in pathogenesis of cold preservation/reperfusion injury in the rat liver graft.

This study was designed to investigate the possible involvement of the thromboxane A2 (TXA2)-TXA2 receptor (TXA2R) system of the hepatic sinusoid in cold preservation/reperfusion injury in liver grafts. Rat livers were preserved in cold University of Wisconsin solution for either 6 or 24 hr. The number of TXA2Rs in sinusoidal endothelial cells isolated from 0-, 6-, and 24-hr preserved liver specimens was 22.50 +/- 1.80 x 10(3)/cell, 12.66 +/- 1.00 x 10(3)/cell, and 4.17 +/- 0.65 x 10(3)/cell, respectively. Kd and Bmax at 0 hr, 6 hr, and 24 hr of preservation were 8.54 +/- 1.26 nM and 37.34 +/- 3.01 fmol/10(6) cells, 7.08 +/- 1.14 nM and 12.66 +/- 1.00 fmol/10(6) cells, and 1.91 +/- 0.10 nM and 3.88 +/- 0.59 fmol/10(6) cells, respectively. The administration of OKY-046 (inhibitor of TXA2 synthesis) to the University of Wisconsin solution suppressed this reduction in TXA2R number. Furthermore, the concentration of TXA2 in hepatic sinusoid was decreased by OKY-046. In a reperfusion experiment, liver tissue preserved for 24 hr exhibited a higher reperfusion pressure, and effluent levels of both aspartate aminotransferase and lactate dehydrogenase were markedly elevated. The addition of OKY-046 to the preservation solution, however, prevented the rise in reperfusion pressure almost completely and the increase in effluent enzyme levels. This study showed that the TXA2Rs in sinusoidal endothelial cells were internalized through binding with TXA2 during cold preservation, causing activation of the TXA2-TXA2R system. This activation apparently induces an increase in reperfusion pressure, possibly due to sinusoidal contraction, resulting in microcirculatory disturbances.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1995

Family with nonmedullary thyroid neoplasms.

This report concerns a family in which papillary thyroid carcinoma appeared in the father and two daughters and follicular adenoma in a granddaughter. The father died of systemic metastasis of papillary thyroid carcinoma. The two daughters and granddaughter felt well postoperatively. We speculate that some gene-related factors might play an important role in familial occurrence of papillary thyroid carcinoma and follicular thyroid adenoma in the family.

Adenoma↗

PubMed1995

Simultaneous occurrence of medullary carcinoma and papillary carcinoma of the thyroid.

We report a case of simultaneous occurrence of medullary carcinoma and papillary carcinoma of the thyroid in the same thyroid gland. Immunoreactivity of calcitonin, carcinoembryonic antigen, neuron specific enolase and thyroglobulin made a sharp distinction between both neoplasms of the thyroid. It appears reasonable to consider that simultaneous occurrence of medullary carcinoma and papillary carcinoma of the thyroid in this case does not have embryological or genetical significance.

Carcinoma, Medullary↗

PubMed1995

Expression of cytokine genes during liver regeneration after partial hepatectomy in rats.

In the present study to demonstrate the relationship between cytokines and liver regeneration we investigated by Northern blot hybridization the cytokine gene induction in the regenerating liver and several other organs (spleen, lung, and kidney) in the rat after partial hepatectomy (PH). We also examined whether Kupffer cells and the spleen are involved in the induction of cytokine mRNA in the regenerating liver. Both IL-1 alpha and beta mRNA increased transiently 1/2 to 1 hr after PH in nonparenchymal cells (NPC) of the regenerating liver; they reached a maximum before the peak of hepatocyte DNA synthesis. PH also induced a slight, but significant, gene expression of IL-1 in lung and kidney in the early postoperative period. TNF-alpha mRNA increased gradually in the spleen, but not the liver, of partially hepatectomized rats at 3 to 12 hr and then reached a peak at 24 hr after PH. IL-6 transcripts were not detected in the regenerating liver, spleen, lung, or kidney during liver regeneration. In contrast, no cytokine gene expression was induced in any of these four organs during the first 3 days after sham operation or unilateral nephrectomy. When Kupffer cell activity was suppressed by gadolinium chloride pretreatment, or when splenectomy was performed 24 hr before PH, the constitutive IL-1 alpha and beta mRNA expressions in NPC of the normal rat liver were completely suppressed. In conclusion, the present study demonstrates, for the first time, the specific kinetics of cytokine gene expression in the liver, spleen, lung, and kidney after PH.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1995

Participation of hepatic macrophages and plasma factors in endotoxin-induced liver injury.

The present study was designed to investigate the mechanism responsible for endotoxin-induced liver injury, based on the working hypothesis that hepatic macrophages activated by endotoxin play a key role in the development of this injury. At both the protein and the transcription levels, the intravenous administration of endotoxin was shown to have increased the capacity of hepatic macrophages to produce chemical mediators. To inhibit the function of hepatic macrophages, gadolinium chloride (GdCl3), a specific inhibitor of resident hepatic macrophages, was preadministered to rats before endotoxin injection. GdCl3 reduced the elevated glutamic oxaloacetic transamiase and lactate dehydrogenase serum levels produced by endotoxin treatment, suppressed the increased mRNA expression of tumor necrosis factor (TNF-alpha) produced in liver nonparenchymal cells by endotoxin, and then improved the survival rate of lipopolysaccharide-injected rats. These results indicated that hepatic macrophages played a crucial role in liver injury and that TNF-alpha was the most likely factor implicated in the development of endotoxin-induced liver injury. Furthermore, we found that liver injury did not progress during perfusion of endotoxin-pretreated extirpated liver with lactate Ringer's solution, whereas liver perfused with plasma developed remarkable hepatic impairment, which was inhibited almost completely by GdCl3-pretreatment; moreover, addition of heparin to the perfusate also prevented this deterioration. Thus, the present study showed that the activation of hepatic macrophages and factors in the plasma were two essential elements in the occurrence and development of endotoxin-induced liver injury.

Animals↗