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Biomedical subjects

Y Kitagawa

Publications and source records attributed to Y Kitagawa.

At least 235 records · Page 13Linked to original sources
PubMed1992

Turner's syndrome associated with Hashimoto's thyroiditis and sarcoidosis: a case report.

A 32-yr-old Japanese female who was suffering from Turner's syndrome associated with Hashimoto's thyroiditis and sarcoidosis is reported. It is known that Hashimoto's thyroiditis is not infrequently complicated with Turner's syndrome on the basis of an abnormal X chromosome. In this case, sarcoidosis occurred 4 months after Hashimoto's thyroiditis. This extremely interesting coincidence of Hashimoto's thyroiditis and sarcoidosis in Turner's syndrome has not been reported to date to our knowledge.

Adult↗
PubMed1992

Prediction of insulin dependent diabetes mellitus in non-obese diabetic mice by the endogeneous tumor necrosis factor-alpha level.

The non-obese diabetic (NOD) mouse is an animal model of human insulin dependent diabetes mellitus (IDDM). In this strain, the serum concentration of tumor necrosis factor-alpha (TNF alpha) after OK432 (a streptococcal preparation) stimulation is much lower than in any other non-diabetic control strain. Female NOD mice which have a higher incidence of diabetes have significantly lower TNF alpha level (6.5 +/- 4 U/ml, mean +/- SEM) than do male NOD mice (21 +/- 5 U/ml) (P < 0.02) which have lower incidence of diabetes. On the basis of these results, we designed a prospective study to evaluate the relationship between the serum TNF alpha concentration and the incidence of diabetes in individual male NOD mice. Mice were studied until 30 weeks of age. During this period four of eight mice with a low TNF alpha level (TNF alpha < or = 1.1 U/ml) became diabetic, whereas none of eighteen mice with a high TNF alpha level (TNF alpha > 1.1 U/ml) developed overt diabetes. These results indicate that by measuring of endogeneous TNF alpha level after stimulation by OK432, one could predict IDDM in male NOD mice.

Aging↗
PubMed1992

[A multicenter, fixed-flexible dose study of terazosin hydrochloride in the treatment of symptomatic benign prostatic hypertrophy].

In this study the multicenter, fixed-flexible dose regimen was taken to evaluate the effective dose range of Terazosin for the treatment of micturition disturbance in benign prostatic hypertrophy (BPH) and to clarify the characteristics of patients who are more responsive to Terazosin therapy. After a 1-week washout (placebo) the first two weeks 1 mg/day of Terazosin was administered, then depending on efficacy of subjective symptoms, Terazosin doses were increased up to 2 mg/day and 4 mg/day at intervals of two weeks. After six weeks the final efficacy and safety were assessed. The subjective symptom improvement rate was 18.5% by 1 mg/day, 55.6% by 2 mg/day and 65.4% by 4 mg/day cumulatively. The objective symptom improvement rate were 13.2% by 1 mg/day, 42.1% by 2 mg/day and 50.0% by 4 mg/day cumulatively. The global improvement rate was 14.5% by 1 mg/day, 50.0% by 2 mg/day and 61.8% by 4 mg/day cumulatively. The patients who had a higher subjective symptom score in the lead-in period were more improved rather than those who had a lower score. In objective symptoms, voided volume, maximum flow rate (MFR), MFR nomogram score and average flow rate improved and the ratio of residual urine volume decreased. There was no relationship between clinical improvement on either subjective or objective symptoms and prostatic weight. Adverse reactions, such as dizziness, vertigo, tinnitus, nausea and blurred vision; were seen in 10 cases. In conclusion Terazosin was effective and well tolerated for the treatment of patients who had micturition disturbance with BPH in the dose range of 2 to 4 mg/day.

Adrenergic alpha-Antagonists↗
PubMed1992

Nonmetric tooth crown traits in the Ami tribe, Taiwan aborigines: comparisons with other east Asian populations.

The frequencies of occurrence of 17 tooth crown traits in the living Ami tribe, which inhabits the east coast of Taiwan, were investigated and compared with other East Asian populations based on Turner's (1987) Mongoloid dental variation theory. Principal coordinate analysis based on Smith's mean measure of divergence using frequencies of the 17 traits suggests that the Ami tribe together with the Yami tribe and the Bunun tribe is included in the sinodont group typical of the Chinese mainland and northeast Asia. In light of these results and the estimated distribution of sinodonty and sundadonty in the past and the present, we speculate that the gene flow from Chinese mainlanders to native sundadonts, who seem to have migrated northward to Taiwan, contributed significantly to the formation of the living Taiwan aboriginal groups, sinodonts. Among the aboriginal tribes of Taiwan, the Ami have characteristics intermediate between those of the Yami and the Bunun. The relative positions of these tribes in East Asian populations suggests that the extent of sinodontification and of genetic isolation is one of the causes of the intertribal variation.

Adolescent↗
PubMed1992

[Rapid detection of mecA gene by nested PCR for diagnosis of methicillin resistance in Staphylococcus aureus].

In recent years, the most common causative organism of hospital infections has been methicillin resistant Staphylococcus aureus (MRSA). The major mechanism of beta-lactam resistance in MRSA is attributed to the production of a specific penicillin binding protein (PBP2'), which is a product of mecA gene, with extremely low binding affinities to beta-lactams. In the present study, we have established a rapid identification method of MRSA by sensitive detection of mecA gene using nested PCR. Nested PCR method amplifying the target DNA in two steps enhanced the efficiency of the second round amplification. By means of this method, mecA gene was successfully detected in clinical samples, such as blood, pus, sputum and feces within 3-4 hrs. Rapid diagnosis of MRSA-bacteremia is particularly important for prevention of sever systemic infection. There are some strains of S. aureus which possess mecA gene in spite of low minimal inhibitory concentration of DMPPC. In these strains expression of mecA gene is induced by contact of beta-lactams and they obtain methicillin resistance. Using nested PCR method, these latent MRSA are rapidly and certainly detectable. This method should be useful for early and effective detection of MRSA hospital infections.

Cross Infection↗
PubMed1991

Protein kinase C of a human megakaryoblastic leukemic cell line (MEG-01). Analysis of subspecies and activation by diacylglycerol and free fatty acids.

Protein kinase C (PKC) from a human megakaryoblastic leukemic cell line (MEG-01) was resolved into two fractions by hydroxyapatite column chromatography, which are indistinguishable from the brain type II (beta I/beta II) and type III (alpha) subspecies, by biochemical and immunoblot analysis. In the presence of both phosphatidylserine and diacylglycerol, several free unsaturated fatty acids (FFA's), such as arachidonic, oleic, linoleic and linolenic acids, further enhanced the enzyme activation, and allowed the enzyme to exhibit almost full activity at nearly basal levels of Ca2+ concentration. The concentration of unsaturated FFA's giving rise to the maximum enzyme activation was around 2 x 10(-5) M. Palmitic and stearic acids were inactive. The result implies that, in addition to diacylglycerol, the receptor-mediated release of unsaturated FFA's from membrane phospholipids may also take part in the activation of PKC.

Arachidonic Acid↗
PubMed1991

Identification of the promoter region of the rat protein phosphatase 2A alpha gene.

We have cloned a genomic fragment containing the promoter region of the rat protein phosphatase 2A alpha gene (PP-2A alpha). A 1.6 kb fragment of the 5' flanking region was sequenced. Three major transcriptional initiation sites were identified by the primer extension method using rat liver mRNA and found to be located 225, 222 and 220 bases upstream of the translational initiation site, respectively. Bacterial chloramphenicol acetyltransferase (CAT) assay revealed that a 503 bp SmaI fragment containing the transcriptional initiation sites had promoter activity, which was stronger than that of the SV40 early promoter on the pSV2CAT plasmid when introduced into NIH3T3 cells. Deletion of a 119 bp SacII fragment decreased its promoter activity considerably. The promoter region has an extremely high GC content and does not contain either a 'TATA box' or a 'CAAT box' suggesting that this promoter can be classified as that of a 'house keeping' gene, although there is only one typical GC-box (GGGCGG) immediately preceding the transcriptional initiation sites. There is a 10 base pair palindrome, 5'-GTGACGTCAC-3', 26 base pairs upstream of the +1 transcriptional initiation site, which is highly conserved in many other genes, whose expression is regulated by cAMP. The promoter activity was shown to be increased by forskolin treatment (10 microM) in NIH3T3 cells.

Amino Acid Sequence↗
PubMed1991

Preparation of human manganese superoxide dismutase by tri-phase partitioning and preliminary crystallographic data.

Human liver manganese superoxide dismutase has been purified by a short procedure that includes a tri-phase partitioning step to provide materials that can be crystallized from ammonium sulfate. X-ray diffraction studies at 3 A resolution show that the crystals belong to the hexagonal space group P6(1)22 or P6(5)22, with cell dimensions a = b = 81.1 A, c = 242.2 A. Manganese superoxide dismutase levels as determined by enzymatic assay as well as by enzyme-linked immunosorbent assay indicated that considerable variations occur in different livers but the total superoxide dismutase activity (Mn superoxide dismutase plus Cu,Zn superoxide dismutase) seems to be kept at constant values.

Ammonium Sulfate↗
PubMed1991

Significance of int-2/hst-1 coamplification as a prognostic factor in patients with esophageal squamous carcinoma.

The correlation between the clinical outcome in patients with esophageal squamous cell carcinoma and coamplification of the proto-oncogenes int-2 and hst-1, which are partially homologous to angiogenesis-inducing fibroblast growth factor, was analyzed retrospectively. Coamplification of these genes was examined by slot-blot hybridization using DNAs extracted from formalin-fixed and paraffin-embedded blocks of tissues. These tissues were obtained from 107 patients with esophageal squamous cell carcinoma who had undergone radical surgery. Int-2/hst-1 coamplification greater than 3-fold was observed in the primary tumors of 30 of 107 cases (28%), and in the metastatic lymph nodes of 12 of 40 cases (30%). The cumulative survival rate of patients with int-2/hst-1 coamplification in the primary tumors was significantly lower than that of the patients without coamplification (P less than 0.001), and there were no significant differences between the clinicopathological backgrounds of the 2 groups. Int-2/hst-1 coamplification was also significantly correlated with a high incidence of eventual metastasis in distant organs in these patients. These results suggest that int-2/hst-1 coamplification is a new biological indicator of prognosis and distant organ metastasis in patients with esophageal squamous cell carcinoma.

Carcinoma, Squamous Cell↗
PubMed1991

Hypoxic depression of mitochondrial mRNA levels in HeLa cell.

Steady-state levels of 12 S and 16 S mitochondrial (mt) rRNAs and four mRNAs (NADH dehydrogenase subunits 3 and 4/4L, cytochrome c oxidase subunit III, H(+)-ATPase subunits 6/6L) were estimated by hybridization of cellular RNA with cloned human mt DNA fragments during hypoxia of HeLa cells. When the partial pressure of oxygen (pO2) was shifted from 135 to 15 Torr, the level of all mRNAs coordinately decreased more than 95% in 48 h, while that of rRNAs remained virtually unchanged. mRNA levels recovered within 4-6 h of reexposure to normoxia. The depression was observed at pO2 less than 40 Torr, the physiological pO2 in peripheral tissues. During these transitions, the growth rate of HeLa cells and the copy number of mt DNA per cell remained unchanged. The degradation rate of mt mRNAs in the presence of cordycepin was not affected by pO2. In contrast to the in vivo results, the potential activity of transcription in isolated mitochondria assayed under optimum conditions was not affected by previous hypoxic exposure of the cells. These observations provide evidence for the existence of a new mechanism controlling mitochondrial gene transcription.

Adenosine Triphosphate↗
PubMed1991

Morphologic changes in detrusor muscles of patients with chronic obstruction of lower urinary tract. Electronmicroscopic and immunohistochemical findings.

The anterior bladder wall and actin- and myosin-like immunoreactivities within the detrusor muscles in patients with chronic obstruction of the lower urinary tract were examined by means of a MOP Videoplan image-processing system, electronmicroscopy, and light microscopic immunohistochemistry. The image-processing system demonstrated an excess of connective tissue elements between smooth muscle bundles in the anterior wall of the bladder similar to the results of previous studies dealing with the trabeculated posterior wall. Under electronmicroscopy, myofilaments were shown to be multidirectionally arranged in the smooth muscle cells in contrast to the regular arrangement in controls. Dense areas in the cytoplasm of the detrusor muscle also appeared to be abnormally distorted and/or elongated in the electronmicrographs. In support of these findings, actin- and myosin-like immunoreactivities in the muscle layer of the bladder were significantly less intense than in the controls. These results suggest that chronic obstruction of the lower urinary tract causes histopathologic alterations in both the intervening connective tissue and the detrusor muscle. This study raises the possibility that the aforementioned morphologic abnormalities are involved in the occurrence of uninhibited detrusor contraction and abnormal detrusor reflex in patients with lower urinary tract obstruction.

Actin Cytoskeleton↗
PubMed1991

Islet cells but not thyrocytes are susceptible to lysis by NK cells.

BB rats develop both pancreatic insulitis and lymphocytic thyroiditis, but whereas spontaneous autoimmune diabetes is common, hypothyroidism is rare. Splenic natural killer (NK) cells from acutely diabetic (AD) BB rats and from athymic nude rats are known to be cytotoxic to rat islet cells in vitro. To investigate possible differential tissue susceptibility to lysis by NK cells or their cytokines such as cytolysin (perforin) or NK cytotoxic factor (NKCF), we used an in vitro 51Cr-release assay to measure the cytotoxicity of splenocytes, cytolysin or NKCF against Wistar Furth (WF) and Fischer 344 (F-344) rat islet cells, and FRTL-5 F-344-derived and WRT Wistar-derived rat thyrocytes. The results demonstrated that spleen cells from AD-BB (RT1u) rats and athymic F-344 nude (RT11) rats are cytotoxic to WF (RT1u) islets and F-344 (RT11) islets, but not to FRTL-5 (RT11) or WRT (class I RT11) thyrocytes. WF and F-344 rat spleen cells were not cytotoxic to any of these cells. Thyrocytes are known to express class II molecules on their surface in chronic thyroiditis. We found that treatment of thyrocytes with interferon-gamma (IFN-gamma) induced class II expression but did not increase the cytotoxicity of splenocytes against these cells. Cytolysin and NKCF were both cytotoxic to islets in a dose dependent manner, but FRTL-5 thyrocytes were resistant to killing by these cytokines. These findings suggest that islet cells and thyrocytes in vitro are differentially susceptible to lysis by NK cells.

Animals↗
PubMed1991

Heterogeneity of immune complex-derived anti-DNA antibodies associated with lupus nephritis.

The mechanisms responsible for the tissue injuries associated with lupus nephritis have not yet been well explained. We have investigated the characteristics of anti-DNA antibodies in circulating immune complexes (CIC) and in the deposits of renal glomeruli in patients with active lupus nephritis. The CIC-derived antibodies expressed anti-DNA idiotypes (Id) designated as 0-81 Id and NE-1 Id, and bound mainly to single-stranded DNA but never to glomerular basement membrane (GBM) antigens. On the other hand, the immunoglobulins (Ig) eluted from renal glomeruli of lupus patients reacted not only with DNA but also with GBM, proteoglycan, and heparan sulfate. The binding of glomeruli-deposited Ig was markedly low when GBM antigens were used after treatment with heparitinase, suggesting that some anti-DNA antibodies may bind directly to GBM antigens associated with heparan sulfate, and form in situ IC in renal glomeruli. It was also revealed that the renal eluates obtained after passing through GBM antigen-coupled Sepharose lost the binding ability with GBM but still retained DNA-binding and 0-81 Id activity, showing the participation of circulating IC-derived anti-DNA antibodies in the glomerular deposits. Theoretically there may be two mechanisms in the pathogenesis of lupus nephritis through the deposition of circulating IC and through in situ formation of anti-DNA IC in renal glomeruli. The diversity of histological features in lupus kidneys may be attributed to the heterogeneity of the mechanisms.

Antibodies, Antinuclear↗
PubMed1991

Three-dimensional structure of Cu,Zn-superoxide dismutase from spinach at 2.0 A resolution.

The three-dimensional structure of Cu,Zn-superoxide dismutase from spinach leaves has been determined by X-ray crystal structure analysis. The atomic coordinates were refined at 2.0 A resolution using the Hendrickson and Konnert program for stereochemically restrained refinement against structure factors, which allowed the use of non-crystallographic symmetry. The crystallographic residual error for the refined model was 24.9%, with a root mean square deviation of 0.03 A from the ideal bond length and an average atomic temperature factor of 9.6 A. A dimeric molecule of the enzyme is comprised of two identical subunits related by a non-crystallographic 2-fold axis. Each subunit of 154 amino acid residues is composed primarily of eight anti-parallel beta-strands that form a flattened cylinder, plus three external loops. The main-chain hydrogen bonds primarily link the beta-strands. The overall structure of this enzyme is quite similar to that of the bovine dismutase except for some parts. The single disulfide bridge (Cys57-Cys146) and the salt bridge (Arg79-Asp101) may stabilize the loop regions of the structure. The Cu2+ and Zn2+ ions in the active site lie 6.1 A apart at the bottom of the long channel. The Cu2+ ligands (ND1 of His-46, and NE2 of His-48, -63, and -120) show an uneven tetrahedral distortion from a square plane. The Zn2+ ligands (ND1 of His-63, -71, and -80 and OD1 of Asp-83) show an almost tetrahedral geometry. The imidazole ring of His-63 forms a bridge between the Cu2+ and Zn2+ ions.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1991

Crystal structure of basic fibroblast growth factor at 1.6 A resolution.

We have determined the crystal structures of two types of human basic fibroblast growth factor, the serine analogue and the wild-type, at 1.6 and 2.5 A resolution, respectively. Two good heavy atom derivatives were found and used for multiple isomorphous replacement phasing. The atomic coordinates were refined using the Hendrickson & Konnert program for stereochemically restrained refinement against structure factors. The crystallographic R factors were reduced to 15.3% for the serine analogue structure and 16.0% for the wild-type structure. The serine analogue and wild-type structures have been found to be almost identical, the root-mean-square deviation between the corresponding C alpha atoms being 0.11 A. Their structures are composed of twelve beta-strands forming a barrel and three loops. Their molecules have an approximate threefold internal symmetry and are similar in architecture to that of interleukin-1 beta. A possible heparin-binding site, which comprises five basic residues, Lys119, Arg120, Lys125, Lys129, and Lys135, has been revealed by calculating the electrostatic potential energy.

Amino Acid Sequence↗