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Biomedical subjects

K Ohta

Publications and source records attributed to K Ohta.

At least 73 records · Page 4Linked to original sources
PubMed2001

B-type cyclins CLB5 and CLB6 control the initiation of recombination and synaptonemal complex formation in yeast meiosis.

BACKGROUND: The life cycle of most eukaryotic organisms includes a meiotic phase, in which diploid parental cells produce haploid gametes. During meiosis a single round of DNA replication is followed by two rounds of chromosome segregation. In the first, or reductional, division (meiosis I), which is unique to meiotic cells, homologous chromosomes segregate from one another, whereas in the second, or equational, division (Meiosis II) sister centromeres disjoin. Meiotic DNA replication precedes the initiation of recombination by programmed Spo11-dependent DNA double-strand breaks. Recent reports that meiosis-specific cohesion is established during meiotic S phase and that the length of S phase is modified by recombination factors (Spo11 and Rec8) raise the possibility that replication plays a fundamental role in the recombination process. RESULTS: To address how replication influences the initiation of recombination, we have used mutations in the B-type cyclin genes CLB5 and CLB6, which specifically prevent premeiotic replication in the yeast Saccharomyces cerevisiae. We find that clb5 and clb5 clb6 but not clb6 mutants are defective in DSB induction and prior associated changes in chromatin accessibility, heteroallelic recombination, and SC formation. The severity of these phenotypes in each mutant reflects the extent of replication impairment. CONCLUSIONS: This assemblage of phenotypes reveals roles for CLB5 and CLB6 not only in DNA replication but also in other key events of meiotic prophase. Links between the function of CLB5 and CLB6 in activating meiotic DNA replication and their effects on subsequent events are discussed.

Cyclin B↗
PubMed2001

Determination of chromium in river waters by electrothermal atomic absorption spectrometry with preconcentration on a tantalum wire.

The preconcentration of chromium on tantalum wire followed by electrothermal atomic absorption spectrometry with a tungsten tube atomizer is described. The preconcentration is accomplished by adsorbing chromium on a tantalum wire. The optimal immersion time was 3 mm. The best pH for chromium adsorption was 3. Under optimal conditions, the detection limit was 15 pg mU1 (3 x SIN). The effects on the preconcentration of chromium by large amounts of contaminants were evaluated. Even though matrix elements existed in 10(3)-10(4)-fold excess in water, the chromium absorption signal was not affected by the matrix elements. The method with preconcentration on tantalum wire was applied to the determination of chromium in river water.

Adsorption↗
PubMed2001

Virus-associated hemophagocytic syndrome due to rubella virus and varicella-zoster virus dual infection in patient with adult idiopathic thrombocytopenic purpura.

A 26-year-old woman with idiopathic thrombocytopenic purpura (ITP) was admitted to our hospital because of fever and rash. Blood tests revealed thrombocytopenia, liver dysfunction, coagulopathy, and hyperferritinemia. Bone marrow examination revealed many atypical lymphocytes and some histiocytes with hemophagocytosis. On admission she was diagnosed with rubella virus-associated hemophagocytic syndrome (VHAS), but on laboratory examination, she was seropositive for varicella-zoster virus (VZV)-IgM as well as rubella virus-IgM. She was therefore diagnosed with dual infection by rubella virus and VZV. Her simultaneous rubella virus and VZV infection may have been related to the VAHS pathogenesis. She was treated with prednisolone and gamma globulin therapy and recovered completely.

Adult↗
PubMed2001

Bone resorption associated with uncoupling of osteoclastic and osteoblastic activities in adult T cell leukemia with hypercalcemia: case report.

A 64-year-old woman with adult T cell leukemia (ATL) was admitted to our hospital with severe hypercalcemia. The serum calcium level was elevated to 14.9 mg/dl. Biochemical parameters for bone formation including serum osteocalcin (bone Gla protein, BGP) and alkaline phosphatase (ALP) were normal. The serum levels of tartrate-resistant acid phosphatase (TRAP), a parameter for bone resorption, were increased (4.6 KAU). The serum level of parathyroid hormone-related protein (PTHrP) was elevated (343 pmol/l). The cytokines with stimulatory effects on bone resorption, such as interleukin (IL)-1alpha, IL-1beta, IL-6, and tumor necrosis factor-alpha, were not detected. Serum Ca levels, PTHrP levels, and TRAP levels decreased with the decrease in ATL cells after chemotherapy, while serum BGP levels and ALP levels increased. On the 29th hospital day, ATL cells began to increase again. Then serum PTHrP levels, Ca levels, and TRAP levels increased, while serum BGP levels and ALP levels decreased. A marked excessive bone resorption with suppressed bone formation (uncoupling) occurred in this patient. The ATL cells produced not only PTHrP but also IL-1alpha and IL-1beta. These results suggest that PTHrP may act as a humoral factor and IL-1 may act as a local factor in bone metabolism of ATL patients.

Bone Resorption↗
PubMed2001

Fournier's gangrene: report of six cases.

Fournier's gangrene (FG) is a fatal infectious disease with necrotic fasciitis of the external genitalia. This disease persists to this day in spite of recent advances in antibiotics. Although fewer than 100 cases have been reported in Japan, we have treated six cases in the last 4 years. The patients consisted of five men and one woman, with an average age of 47.5 years. All patients received surgical treatment including incisions, aggressive debridement, drainage, irrigation, and antibiotic therapy. Two patients, who suffered from underlying diseases of diabetic nephropathy and inclusion body myositis, died. These findings confirm the fact that FG requires a prompt diagnosis and immediate surgical treatment.

Adult↗
PubMed2001

Lymph node metastasis and preoperative diagnosis of depth of invasion in early gastric cancer.

BACKGROUND: No reports have, to date, focused on the relationship between preoperative determination of the depth of invasion and lymph node metastasis. The present study, under the leadership of the Japanese Gastric Cancer Association, was designed to form a basis for decision making in limited treatment for early gastric cancer (EGC). METHODS: From eight major hospitals in Japan, 2672 gastric cancers whose preoperative depth of invasion was mucosal(M-cancer), and 6209 EGCs, consisting of 3584 mucosal(m-) and 2625 submucosal(sm-) cancers, were collected by questionnaire. All registered patients underwent gastrectomy with D1 or more extensive lymphadenectomy between 1985 and 1998. RESULTS: The accuracy of preoperative diagnosis of depth of invasion of M-cancers was 80.2% (2144/2672). However, of the total of 2432 M-cancers in which no nodal involvement was observed intraoperatively (N0), histological examination of the resected specimens confirmed that lymph node metastasis was absent in 2353 (96.8%). The frequencies of lymph node metastasis in early gastric, m-, and sm-cancers were 8.9%, 2.5%, and 17.6%, respectively. Node involvement was associated with a higher frequency of undifferentiated than differentiated histology, as well as with greater tumor size. The incidences of lymph node metastasis in m-cancers with a diameter of less than 4 cm, and in sm-cancers with a diameter below 1 cm were 1.3% (37/2837) and 4.9% (4/82), respectively. These metastases rarely extended beyond the first tier. CONCLUSION: N0 and M-cancers, m-cancers less than 4 cm in diameter, and sm-cancers no larger than 1 cm in diameter may be appropriate indications for limited surgery.

Chi-Square Distribution↗
PubMed2001

Use of some natural and waste materials for waste water treatment.

A fundamental study was conducted to assess removal and filtration capacity of waste and natural indigenous materials as treatment mediums e.g., shell, limestone, waste paper mixed with refuse concrete, refuse cement, also processed nitrolite, charcoal-bio and charcoal. Under room temperature condition removal of phosphoric, nitric and ammonium-ions, filtration of suspended substance (SS) together with removal of COD in waste water was investigated. Influence of particle size effect for all treatment mediums except for waste paper was pursued. Significant improvement of waste water quality with respect to SS, phosphoric ions and decrease in COD is possible by treating with these filtration mediums. With specific reference to some treatment mediums NO3-N and NH4-N showed reasonable improvement in quality, although generally removal effect was not very significant. Efficacy of treatment was dependent on the particle size of treatment mediums in general, however, nitrolite for NH4--N, charcoal-A for SS and COD, refuse cement mixed with waste paper for PO4 ion removal showed insignificant variability on the particle size effect. Results of this fundamental study demonstrate effectiveness and feasibility for applied application of these proposed waste and naturally available treatment ingredients at lower cost.

Charcoal↗
PubMed2001

Synthesis of sulfoquinovosylacylglycerols, inhibitors of eukaryotic DNA polymerase alpha and beta.

Sulfoquinovosyldiacylglycerols (SQDGs) and sulfoquinovosylmonoacylglycerols (SQMGs), bearing diverse fatty acids, were synthesized from D-glucose, and were examined for enzymatic inhibitions of DNA polymerase alpha and beta. These results indicated that the carbon numbers of the fatty acids were highly related to the activities, at least in vitro, of eukaryotic DNA polymerase inhibition.

Animals↗
PubMed2001

Facial myokymia associated with an isolated lesion of the facial nucleus.

We report on a patient with transient facial myokymia. He had an isolated lesion of the right facial nucleus in the pontine tegmentum. Facial myokymia is a rare symptom and its pathogenesis is not known. Our case had a very localized lesion and we attempted to determine the case of the facial myokymia.

Adult↗
PubMed2001

Growth factors, extracellular matrix components and cell adhesion molecules Warthin's tumor.

We studied expressions of various growth factors, their receptors, cell adhesion molecules and extracellular matrix components in Warthin's tumor of the salivary gland with immunohistochemistry and reverse transcriptase-polymerase chain reaction (RT-PCR). Various growth factors and their receptors, such as transforming growth factor-alpha (TGF-alpha), heparin-binding epidermal growth factor-like growth factor (HB-EGF), TGF-beta2, TG-beta3, insulin-like growth factor (IGF)-I and -II, vascular endothelial growth factor (VEGF), EGF receptor (EGFR), erb-B4, TGF-betaRI and II, Flt and Flk-1 and IGF receptor Ibeta, were found in epithelial cells and/or in some lymphoid cells. Fibronectin, laminin, collagen type IV and tenascin were found in stroma of the lymphoid tissue. Integrins such as alpha3beta1 and beta3, Thy-1, CD44 and VCAM-1 were also expressed in epithelial and/or lymphoid cells. These various proteins may interact and regulate the proliferation and cell attachment of both epithelial and lymphoid components in this unique tumor.

Adenolymphoma↗
PubMed2001

Variations in the human CC chemokine eotaxin gene.

The CC chemokine eotaxin (CCL11) plays a major role in the recruitment and activation of eosinophils in allergic disorders. In the present study, we performed polymorphism screening of the coding and promoter regions of the eotaxin gene (SCYA11). A G to A single nucleotide substitution was detected at position 67, which resulted in a non-conservative amino acid change of Ala at position 23 to Thr (A23T) within the signal peptide. Two single nucleotide substitutions, ie, C to T at position -426 (-426C>T), and A to G at position -384 (-384A>G), were detected in the 5'-flanking regions. Significant linkage disequilibrium was observed between positions -426 and -384, and also between -384 and +67. No significant association was observed between these variations and susceptibility to asthma.

Adult↗
PubMed2001

Primary refractoriness to platelet transfusion caused by Nak(a) antibody alone.

BACKGROUND AND OBJECTIVES: Anti-Nak(a), a platelet-specific antibody, occasionally causes platelet-transfusion refractoriness (PTR) together with human leucocyte antigen (HLA) antibodies. Anti-Nak(a) usually appears after frequent platelet transfusions or pregnancy. We report the first case of PTR caused by anti-Nak(a) alone. MATERIALS AND METHODS: A 19-year-old male patient with testicular tumour showed PTR when receiving his first transfusion of platelets. Screening for platelet antigens and platelet antibodies revealed that he had type I CD36 (Nak(a)) deficiency and that anti-Nak(a), but not anti-HLA, was present before he received his first transfusion. RESULTS: The transfusion of Nak(a)-negative, but HLA non-selected, platelets was effective in raising the platelet count. CONCLUSION: Clinically significant Nak(a) antibody was present as naturally occurring antibody in a platelet glycoprotein IV (CD36)-negative non-transfused male patient.

Adult↗
PubMed2001

The event-related potentials elicited by content and function words during the reading of sentences by patients with schizophrenia.

Thought disorder is one of the main symptoms observed in schizophrenia and has been investigated in terms of language dysfunction. The purpose of the present study was to find whether there were any differences in identifying and processing between content (semantic) and function (syntax) words, and to elucidate whether semantic or syntax is more impaired for the schizophrenics. Event-related potentials were recorded in 13 patients with schizophrenia and 14 healthy controls, while they silently read three sets of passages. Event-related potentials were recorded for content words (noun, verb) and function words (auxiliary verb, particle) separately. For the healthy control group, the mean amplitude of P200 for the content word class was greater than for the function word class with fronto-central dominance. In contrast, no such difference was found for the schizophrenics mainly due to the reduction of P200 amplitude of the content words. Larger P200 for the content than the function word class suggests that greater resources were used to identify the content words. Lack of this difference found in patients with schizophrenia suggested that the disturbances in the semantics may be more attributable to the linguistic impairment than those in the syntax.

Adult↗
PubMed2001

Cytoprotective role of heme oxygenase (HO)-1 in human kidney with various renal diseases.

BACKGROUND: We previously reported that glomerular changes in the renal specimen of a human case with heme oxygenase-1 (HO-1) deficiency were mild, but tubulointerstitial injury advanced progressively. This study examined the patterns of HO-1 production in the kidney in various renal diseases. Furthermore, the critical cytoprotective roles of HO-1 were evaluated in the kidney by comparing HO-1 production and expressions of carboxymethyllysine (CML) and pentosidine, both of which are markers of oxidative stress. METHODS: Renal biopsy or autopsy materials were obtained from a total of 74 patients. Degrees of hematuria and proteinuria and the levels of urinary N-acetyl-beta-D-glucosaminidase (NAG), beta2-microglobulin (beta2m), and creatinine were evaluated. Immunohistochemical studies for HO-1, CML, and pentosidine expressions were performed with their specific antiserum. RESULTS: HO-1 staining was observed within tubular epithelial cells in all of the renal diseases, but was not detected within intrinsic glomerular cells. HO-1 staining tended to be more intense within distal tubuli than in proximal tubuli. Within distal tubuli, there was no significant correlation between intensity of HO-1 staining and degree of hematuria or presence of proteinuria. Within proximal tubuli, HO-1 staining tended to be more intense with greater degrees of hematuria, presence of proteinuria, and moderate tubulointerstitial damage. Intense staining of CML and pentosidine was observed within renal tubular epithelial cells only in HO-1-deficient patients. CONCLUSIONS: HO-1 plays important roles in protecting renal tubuli from oxidative injuries, as these cells are constantly exposed to various oxidative stresses. It is suggested that renal tubular epithelia are more susceptible to oxidative stress due to the lack of this critical enzyme in HO-1 deficiency.

Adolescent↗