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Biomedical subjects

S Mizuno

Publications and source records attributed to S Mizuno.

At least 73 records · Page 4Linked to original sources
PubMed2000

A case of an unclassified tumor closely resembling dysembryoplastic neuroepithelial tumor with rapid growth.

We describe a rare case of a tumor resembling dysembryoplastic neuroepithelial tumor. A 3-year-old girl had a generalized convulsion as the initial symptom, without other neurological deficits. Computed tomography showed a hypodense lesion with calcific hyperdensity in the left frontal lobe associated with deformity of the overlying calvarium. Four months later, she had a second seizure, and computed tomographic scan showed that the lesion had increased in size. Subtotal removal of the tumor was performed, and the postoperative course was uneventful without radiation therapy. Histological examination revealed a cortical lesion in which an oligodendrocyte-like area and an astrocyte-like area with cytological atypia were observed. Although the clinical course and the radiological findings closely resembled those of dysembryoplastic neuroepithelial tumor, specific glioneuronal elements were not found histologically. Daumas-Duport reported a complex form of dysembryoplastic neuroepithelial tumor that contained glial nodules in addition to a specific glioneuronal element. The histological findings of the glial nodules in this case were quite similar to those she described. We conclude that this could be an unclassified tumor closely resembling dysembryoplastic neuroepithelial tumor without a specific glioneuronal element.

Antigens, Nuclear↗
PubMed2000

Ocular and systemic features of Peters' anomaly.

BACKGROUND: To clarify the relationship between associated systemic anomalies and ocular manifestations in patients with Peters' anomaly, a retrospective study was conducted. METHODS: We classified 37 patients with Peters' anomaly into two groups, one with (+) and one without (-) systemic anomalies. RESULTS: The systemic anomaly (+) group consisted of 13 patients, eight males and five females, with mean age of 2.3 months. Peters' anomaly was bilateral in six cases and unilateral in seven. Corneolenticular adhesion was observed in 11 cases. Associated ocular anomalies were seen in 12 cases, and developmental glaucoma was present in eight cases. The systemic anomaly (-) group comprised 24 patients, 13 males and 11 females, with mean age of 28.3 months. Peters' anomaly was bilateral in 11 cases and unilateral in 13. Corneolenticular adhesion was observed in five cases. The associated ocular anomalies were observed in 10 cases, and developmental glaucoma was accompanied in six cases. The incidences of cases with corneolenticular adhesion, those with other ocular anomalies, and those with glaucoma were significantly higher in the systemic anomaly (+) group than in the systemic anomaly (-) group. CONCLUSIONS: Peters' anomaly accompanying corneolenticular adhesion and/or other ocular anomalies should be evaluated for the presence of systemic anomalies.

Corneal Opacity↗
PubMed2000

Three-dimensional computed tomographic angiography in four patients with dissecting aneurysms of the vertebrobasilar system.

BACKGROUND: Recently, three-dimensional computed tomographic angiography (CTA) has been used for the diagnosis and treatment planning of cerebral aneurysm presenting with or without subarachnoid haemorrhage, but the diagnostic value of CTA has not been established. This study evaluated the usefulness of CTA in patients with dissecting aneurysms of the vertebrobasilar system. METHOD: Four patients with acute dissecting aneurysms were examined by CTA, including 3 women and 1 man with a mean age of 60.5 +/- 8.5 years (range: 52-67 years). There were three patients with subarachnoid haemorrhage and one patient presenting with ischaemia. One patient underwent CTA twice and digital subtraction angiography (DSA) once, while one patient had both examinations three times. CTA was performed with a nonionic contrast medium (100 ml of iomeprol 350 mg I/ml) administered via an auto-injector into an antecubital vein at 1.5-1.7 ml/s. To reconstruct three-dimensional images, the volume rendering method was utilized. FINDINGS: All initial CTA studies were performed safely within 5 hours after onset. In patients with subarachnoid haemorrhage, all lesions were demonstrated by finding either the "pearl and string sign" or a "double shadow" on CTA. In the patient presenting with ischaemia, "pearl and string sign" and "double shadow" was shown after the second CTA, and follow-up CTA was able to demonstrate the change of the lesion morphology. All lesions had more irregular luminal surfaces than the non-lesional segments of the involved vessels. INTERPRETATION: CTA was safe in patients with acute vertebrobasilar dissection and demonstrated either the "pearl and string sign" or a "double shadow" which were commonly showed on DSA. An "irregular luminal surface sign" on CTA seems to be one of the characteristics of vertebrobasilar dissection. The view shown by CTA is not less useful than that by DSA to diagnosis and treatment planning in the acute phase of vertebrobasilar dissection, and can also be employed to follow the changes of lesion morphology over time.

Aged↗
PubMed2000

Comparative study of perioperative management of hepatic resection.

In an attempt to identify the factors that influence outcome after hepatic resection, patient background was reviewed and operative morbidity and mortality rates were assessed during two periods: 1985-1988 (group I: N = 96) and 1995-1998 (group II: N = 109). There were no differences in patient background factors between the two groups, but intraoperative blood loss, operative morbidity, and mortality were significantly reduced in group II compared to group I. There has been a significant reduction in postoperative complications, even in cases complicated by liver cirrhosis or obstructive jaundice. As a result of appropriate surgical procedures, postoperative complications in cirrhosis have been markedly decreased. After preoperative percutaneous biliary drainage in obstructive jaundice, attempts have been made to reduce the volume of blood loss even in extensive hepatectomy, the extent of liver resection in poor risk cases has been reduced without sacrificing radicality, and, by minimizing surgical stress, perioperative management has been greatly improved.

Adult↗
PubMed2000

Magnetic resonance spectroscopy of tubers in patients with tuberous sclerosis.

OBJECTIVE: The histological features of cortical tubers in patients with tuberous sclerosis (TS) were studied by the proton magnetic resonance spectroscopy (MRS). MATERIAL AND METHODS: The subjects were 4 children, mean age of 10 years, with clear evidence of tubers on MRI and SPECT. Four age-matched control children served as control subjects. Spectra were acquired over the tuber using short TE. RESULTS: The myoinositol/creatine ratios in the tubers of TS patients were significantly increased compared with those of the control subjects (P < 0.02). The NAA/creatine ratios in the tubers of patients were significantly decreased (P < 0.02). CONCLUSIONS: The decrease of NAA/creatine ratios in the tubers of patients was considered to reflect a reduction of cranial neurons. The increase of myoinositol/creatine ratios in the tubers was thought to reflect an increase of glial cells. Proton MRS might play a role in estimation of histological changes in the neurological diseases.

Adult↗
PubMed2000

Reciprocal balance of hepatocyte growth factor and transforming growth factor-beta 1 in renal fibrosis in mice.

BACKGROUND: Transforming growth factor-beta 1 (TGF-beta 1) plays a central role in the pathogenesis of renal fibrosis. In contrast, hepatocyte growth factor (HGF) may be an important molecule for tissue repair. As TGF-beta 1 is a suppressor molecule for HGF expression, we asked whether a decrease in HGF expression would be accompanied by an increase in TGF-beta 1 and whether the progression of renal fibrosis would be modulated. METHODS: We used the ICR strain-derived glomerulonephritis (ICGN) mice as a model of chronic renal disease and examined changes in local HGF expression during the natural course of renal fibrosis. To determine the significance of intrinsic HGF noted during progression of renal fibrosis, we administered an anti-HGF antibody to mice at the early stage of renal fibrosis. RESULTS: At an early stage of renal fibrosis, the mice showed strong peritubular HGF expression, coinciding with tubular proliferation. In the late stages, the renal HGF level was markedly decreased, coinciding with a reduction in proliferative tubular areas. Renal TGF-beta 1 levels were increased in accordance with expansion of fibrotic areas. Notably, the anti-HGF antibody treatment of early-stage mice decreased the HGF level and reduced tubular areas, whereas collagen-deposited areas were expanded in parallel with increased TGF-beta 1 levels. Consequently, in HGF-neutralized mice, there was a rapid progression of renal dysfunction. CONCLUSIONS: Not only an increase in TGF-beta 1 level, but also a decrease in local HGF expression may be responsible for the manifestation of renal fibrosis, particularly tubular destruction.

Animals↗
PubMed2000

Human thymic epithelial cells maintain long-term survival of clonogenic myeloid and erythroid progenitor cells in vitro.

Precursor cells that migrate into the thymus are still multipotent. Therefore, thymic epithelial cells (TECs) may provide microenvironments not only for T-cell development, but also for maintenance of multipotent precursor cells until they undergo T-cell commitment. In the present study, we performed long-term cultures of CD34+ bone-marrow (BM) cells on TEC lines that were derived from cortical epithelial cells of post-natal thymus, to investigate whether human TECs could maintain long-term nonlymphoid haematopoiesis. Haematopoietic cells maintained in direct contact with established TEC lines were able to generate clonogenic progeny to both myeloid and erythroid cells for periods in excess of 5 weeks. Their abilities to support colony-forming units of granulocytes-macrophages (CFU-GM) and burst-forming units of erythroids (BFU-E) were almost equal to those of BM stromal cells. We observed similar results by using cloned TEC lines derived by limiting dilution, as well as those by using parental TEC lines. Colony-forming activities were maintained even when haematopoietic progenitor cells were physically separated from TEC lines and cultured on microporous membrane. These observations indicate that haematopoiesis maintained in TEC-contact long-term cultures may depend on soluble factors produced by TEC lines. Our results suggest that thymic cortical epithelial cells have the ability to support not only the differentiation of haematopoietic cells, but also long-term survival of clonogenic myeloid/erythroid progenitor cells.

Antigens, CD34↗
PubMed2000

Aberrant expression of HLA-G antigen in interferon gamma-stimulated acute myelogenous leukaemia.

We have analysed the expression of HLA-G in 40 leukaemia samples of various subtypes [seven cases of acute lymphoblastic leukaemia (ALL), 28 cases of acute myelogenous leukaemia (AML), three cases of chronic myelogenous leukaemia (CML) and two cases of chronic lymphocytic leukaemia (CLL)] by flow cytometry using HLA-G-specific monoclonal antibody. No leukaemia samples expressed HLA-G without incubation with interferon (IFN)-gamma. However, six out of 28 (21%) AML samples expressed HLA-G upon incubation with IFN-gamma. These six samples derived from one out of seven M2, two out of eight M4 and three out of five M5. The results indicated that AML cells, especially myelomonocytic leukaemia samples, are capable of expressing the HLA-G molecule.

Case-Control Studies↗
PubMed2000

Investigation of blood flow in meningothelial and fibrous meningiomas by xenon-enhanced CT scanning.

We investigated whether xenon-enhanced computed tomography was able to separate meningothelial meningioma from fibrous meningioma. Cerebral blood flow was studied by xenon-enhanced computed tomography in six patients with incidentally detected intracranial meningiomas. All of the tumors were small (< 32 mm) and there was little or no peritumoral edema. Three patients had meningothelial meningioma and three patients had fibrous meningioma. The tumor blood flow and the contralateral tissue blood flow were determined. The ratio of these parameters was 1.753 +/- 0.467 for meningothelial meningiomas and 0.809 +/- 0.105 for fibrous meningiomas, with a significant difference between the two tumor subtypes (p = 0.0185). There was no correlation between the signal intensity on magnetic resonance imaging and tumor subtype, and the findings on cerebral angiography also did not indicate the subtype. In conclusion, xenon-enhanced computed tomography showed a difference between smaller meningothelial and fibrous meningiomas in patients with normal surrounding brain tissue. We could not confirm that xenon-enhanced computed tomography was able to distinguish the subtype of meningioma because of the small number of subjects in this study, but our findings might expand interest in the clinical use of this method.

Aged↗
PubMed2000

Wpkci, encoding an altered form of PKCI, is conserved widely on the avian W chromosome and expressed in early female embryos: implication of its role in female sex determination.

Two W chromosome-linked cDNA clones, p5fm2 and p5fm3, were obtained from a subtracted (female minus male) cDNA library prepared from a mixture of undifferentiated gonads and mesonephroi of male or female 5-d (stages 26-28) chicken embryos. These two clones were demonstrated to be derived from the mRNA encoding an altered form of PKC inhibitor/interacting protein (PKCI), and its gene was named Wpkci. The Wpkci gene reiterated approximately 40 times tandemly and located at the nonheterochromatic end of the chicken W chromosome. The W linkage and the moderate reiteration of Wpkci were conserved widely in Carinatae birds. The chicken PKCI gene, chPKCI, was shown to be a single-copy gene located near the centromere on the long arm of the Z chromosome. Deduced amino acid sequences of Wpkci and chPKCI showed approximately 65% identity. In the deduced sequence of Wpkci, the HIT motif, which is essential for PKCI function, was absent, but the alpha-helix region, which was conserved among the PKCI family, and a unique Leu- and Arg-rich region, were present. Transcripts from both Wpkci and chPKCI genes were present at significantly higher levels in 3- to 6-d (stages 20-29) embryos. These transcripts were detected in several embryonic tissues, including undifferentiated left and right gonads. When the green fluorescent protein-fused form of Wpkci was expressed in male chicken embryonic fibroblast, it was located almost exclusively in the nucleus. A model is presented suggesting that Wpkci may be involved in triggering the differentiation of ovary by interfering with PKCI function or by exhibiting its unique function in the nuclei of early female embryos.

Amino Acid Sequence↗
PubMed2000

Multiple actin-related proteins of Saccharomyces cerevisiae are present in the nucleus.

An increasing number of actin-related proteins (Arps), which share the basal structure with skeletal actin but possess distinct functions, have been found in a wide variety of organisms. Individual Arps of Saccharomyces cerevisiae were classified into Arps 1-10 based on the relatedness of their sequences and functions, where Arp1 is the most similar to actin, and Arp10 is the least similar. While Arps 1-3 and their orthologs in other organisms are localized exclusively in the cytoplasm, Arp4 (also known as Act3) is localized in the nucleus and is involved in transcriptional regulation. Here we examined the more divergent Arps for possible nuclear functions. We show that Arps 5-9 are localized in the nucleus, but Arp10 is not. The nuclear export signals identified in actin are well conserved in the cytoplasmic Arps, Arps 1-3, but less conserved in the nuclear Arps. Gel filtration chromatography experiments show that the nuclear Arps are larger than monomer in size and thus are present in multi-protein complexes. Since nuclear protein complexes containing Arps are found to be responsible for histone acetylation and chromatin remodeling, it is suggested that most of the divergent Arps are involved in the !transcriptional regulation through chromatin modulation.

Actins↗
PubMed2000

Hepatocyte growth factor in renal regeneration, renal disease and potential therapeutics.

Hepatocyte growth factor (HGF) has mitogenic, motogenic, morphogenic, and anti-apoptotic activities on renal cells and is a potential renotropin for renal protection and repair. In chronic renal failure/fibrosis, HGF in the kidney declines in a reciprocal manner to the increase in transforming growth factor-beta (TGF-beta). Neutralization of HGF by the antibody leads to acceleration of renal failure/fibrosis while HGF administration leads to remarkable attenuation, thus indicating the importance of HGF versus TGF-beta counterbalance in both pathogenesis and therapeutics in cases of chronic renal failure. HGF is being strongly considered for potential treatment of acute and chronic renal failure.

Animals↗
PubMed2000

IL-4 is required for defense against mycobacterial infection.

Although the involvement of T helper (Th1) cells is central to protection against intracellular bacteria, including Mycobacterium tuberculosis, the involvement of Th2 cells, characterized by potent interleukin (IL)-4 secretion in mycobacterial infection is still unclear. In order to clarify the role of IL-4 in murine tuberculosis, IL-4-deficient mutant mice, IL-4 knockout (IL-4 KO) mice, were utilized. The mice were infected with H37Rv, Kurono or BCG Pasteur via an airborne infection route by placing them in the exposure chamber of a Middlebrook airborne infection apparatus. Their capacity to control mycobacterial growth, granuloma formation, cytokine secretion, and nitric oxide (NO) production were examined. These mice developed large granulomas, but not necrotic lesions in the lungs, liver or spleen (P<0.05). This was consistent with a significant increase in lung colony-forming units (CFU). Compared with levels in wild-type mice, upon stimulation with mycobacteria, splenic IL-10 levels were low and IL-6 levels were intermediate, but interferon (IFN)-gamma and IL-12 levels were significantly higher. IL-18 levels were within the normal range. The level of NO production by alveolar macrophages of the IL-4 KO mice was similar to that of the wild-type mice. Granulomatous lesion development by IL-4 KO mice was inhibited significantly by treatment with exogenous recombinant IL-4. These findings were not specific to the IL-4 KO mice used. Our data show that IL-4 may play a protective role in defense against mycobacteria, although IFN-gamma and TNF-alpha play major roles in it. Our data do not rule out an IFN-gamma-independent function of IL-4 in controlling tuberculosis.

Animals↗
PubMed2000

Conserved synteny between the chicken Z sex chromosome and human chromosome 9 includes the male regulatory gene DMRT1: a comparative (re)view on avian sex determination.

Sex-determination mechanisms in birds and mammals evolved independently for more than 300 million years. Unlike mammals, sex determination in birds operates through a ZZ/ZW sex chromosome system, in which the female is the heterogametic sex. However, the molecular mechanism remains to be elucidated. Comparative gene mapping revealed that several genes on human chromosome 9 (HSA 9) have homologs on the chicken Z chromosome (GGA Z), indicating the common ancestry of large parts of GGA Z and HSA 9. Based on chromosome homology maps, we isolated a Z-linked chicken ortholog of DMRT1, which has been implicated in XY sex reversal in humans. Its location on the avian Z and within the sex-reversal region on HSA 9p suggests that DMRT1 represents an ancestral dosage-sensitive gene for vertebrate sex-determination. Z dosage may be crucial for male sexual differentiation/determination in birds.

Amino Acid Sequence↗
PubMed2000

Enhanced expression of hepatocyte growth factor by pulmonary ischemia-reperfusion injury in the rat.

Hepatocyte growth factor (HGF) has recently been noted to function as a pulmotrophic factor for lung regeneration. The present study was conducted to determine if HGF would be induced in a rat model of pulmonary ischemia-reperfusion (IR) injury, which was established by occlusion of the left lung, and to examine the significance of HGF in subsequent lung repair. The sham-operated rats underwent simple thoracotomy in which the lung was not clamped. We measured the plasma and the tissue levels of HGF by enzyme-linked immunosorbent assays, and the expression of HGF mRNA by Northern blotting. The plasma HGF level was markedly elevated after pulmonary ischemia and reached the peak value on the third postoperative day, being 5-fold higher than that of the sham-operated rats. HGF mRNA expression and the tissue HGF levels were augmented twofold in the ischemic reperfused lung. Immunohistochemical analysis revealed that the infiltrating alveolar macrophages were intensely stained for HGF. DNA synthesis of alveolar epithelial cells, as identified by proliferating cell nuclear antigen (PCNA) staining, was 3-fold higher in the reperfused lung than in the sham-operated lung. Notably, HGF-neutralizing treatment with an anti-HGF antibody reduced DNA synthesis of alveolar epithelial cells in the reperfused lung and aggravated lung injury. This study shows that HGF was induced in the ischemic reperfused lung and may play an important role in regeneration of an injured lung after pulmonary IR.

Animals↗
PubMed2000

Myocardial protection from ischemia/reperfusion injury by endogenous and exogenous HGF.

Using a rat model of ischemia/reperfusion injury, we demonstrate here that HGF is cardioprotective due to its antiapoptotic effect on cardiomyocytes. Following transient myocardial ischemia and reperfusion, c-Met/HGF receptor expression rapidly increased in the ischemic myocardium, an event accompanied by a dramatic increase in plasma HGF levels in the infarcted rats. When endogenous HGF was neutralized with a specific antibody, the number of myocyte cell deaths increased markedly, the infarct area expanded, and the mortality increased to 50%, as compared with a control group in which there was no mortality. Plasma from the myocardial infarcted rats had cardioprotective effects on primary cultured cardiomyocytes, but these effects were significantly diminished by neutralizing HGF. In contrast, recombinant HGF administration reduced the size of infarct area and improved cardiac function by suppressing apoptosis in cardiomyocytes. HGF rapidly augmented Bcl-xL expression in injured cardiomyocytes both in vitro and in vivo. As apoptosis of cardiomyocytes is one of the major contributors to the pathogenesis in subjects with ischemia/reperfusion injury, prevention of apoptosis may prove to be a reasonable therapeutic strategy. Supplements of HGF, an endogenous cardioprotective factor, may be found clinically suitable in treating subjects with myocardial infarction.

Animals↗
PubMed2000

Does hyperuricemia affect mortality? A prospective cohort study of Japanese male workers.

A positive association between hyperuricemia and cardiovascular disease has been reported, but no study has evidenced yet the precise role of serum uric acid in the development of cardiovascular disease. In addition, no epidemiological studies have so far documented a decreased risk of cancer among people with hyperuricemia, even though the antioxidant action of uric acid has recently been stressed to inhibit DNA damage. The present prospective cohort study investigates the relationship between hyperuricemia and health hazards in a Japanese working population. The subjects were 49,413 Japanese male railroad workers, aged 25-60 years at enrollment. Serum uric acid and other baseline data were provided by annual health-survey records from 1975 to 1982. The vital status of the subjects was traced until the end of 1985 for those who remained alive. During an average 5.4-year study period, 984 deaths were recorded. Those with serum uric acid over 8.5 mg/dl showed elevated relative risks (RRs) of death in all causes (RR 1.62, p<0.01), coronary heart disease ( RR 1.52), stroke (RR 2.33, p<0.01), hepatic disease (RR 3.58, p<0.01), and renal failure ( RR 8.52, p<0.01), as compared with those with serum uric acid levels of 5.0-6.4mg/dl. The RR of death in all causes still remains statistically significant when adjusted by age and serum total cholesterol (2.00, p<0.01), age and alcohol intake (1.85, p<0.001), age and smoking (1.69, p<0.001), age and gout treatment (1.61, p<0.05), and also age and BMI (1.50, p< 0.05). On the other hand, the RR of all causes decreased but was still above 1.0 when adjusted by age and blood glucose (1.62), age and systolic blood pressure (1.32), age and GOT (1.23), and also age and history of cardiovascular disease (1.17). These results showed that hyperuricemia has a strong association with the RRs of death in all causes, coronary heart disease, stroke, hepatic disease and renal failure, and indicated that serum uric acid seems to be a considerable risk factor for reduced life expectancy.

Adult↗