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Biomedical subjects

M Katayama

Publications and source records attributed to M Katayama.

At least 91 records · Page 5Linked to original sources
PubMed1997

[A patient with spontaneous intracranial hypotension--comparison between MRI findings and meningeal pathology].

We report a 44-year-old woman with spontaneous intracranial hypotension (SIH) who developed an acute, severe, nonthrobbing headache. The headache remained more severe in the occipital region and was markedly worse with upright posture. Cerebrospinal fluid (CSF) examination revealed an opening pressure of 55 mmH2O, and the CSF contained 38 cells/mm3 and 57 mg/dl of protein. The results of other laboratory examinations were unremarkable. T1-weighted MR images (MRI) of the head revealed an extensive diffuse pachymeningeal gadolinium enhancement and bilateral subdural fluid accumulation. On the 21st hospital day, a meningeal biopsy was performed through a right parietal craniotomy. On histologic examination, the dural border cell layer demonstrated nonspecific granulation tissue with mild inflammatory changes. The remaining layers of the dura mater and the arachnoid membrane showed no obvious pathological changes. We speculated that the inflammatory changes of the dural border cell layer correspond to the zone of pachymeningeal gadolinium enhancement of the MRI. The granulation tissue of the dural border cell layer and subdural fluid accumulation may represent secondary reactive phenomena, and were suspected to have been caused by downward displacement of the brain due to decreased intracranial pressure.

Adult↗
PubMed1996

Development of porcine blastocysts from in vitro- matured and activated haploid and diploid oocytes.

The purpose of this study was to determine the developmental capacity of electro-activated porcine oocytes. Follicular oocytes collected from gilts at local slaughterhouses were matured for 48 h and were then subjected to a single square pulse of direct current for 100 rhojusec at 1,500 V/cm for activation. To obtain activated diploid oocytes, some were treated with 5.0 micro/ml cytochalasin B for 4 h immediately after electro-activation. The frequency of activation ranged from 96 to 100%. While 91% of activated oocytes that had not been treated with cytochalasin B had 2 polar bodies and a nucleus (haploids), 92% of the oocytes treated with cytochalasin B had only the first polar body and 2 nuclei (diploids). Haploids and diploids were further cultured in TCM-199 medium that contained 10% (v/v) heat- treated fetal calf serum (FCS) and 0.1 mg/ml sodium pyruvate (mTCM) or in Whittenk medium plus 0.4% (w/v) bovine serum albumin (BSA). The frequency of abnormal oocytes was significantly higher in mTCM (83%) than in Whitten's medium (65%) 96 h after the electro-activation (P < 0.01), suggesting that Whitten's medium supported the development of activated oocytes beyond the morula stage. In all cases, several oocytes developed to the blastocyst stage 144 h after electro- activation (1 to 12%). The frequency was significantly higher in the case of diploids cultured in Whitten's medium (12%) (P < 0.01) than in the case of haploids cultured in Whitten's medium (4%), or in the case of haploids cultured in mTCM (1%). The mean number of nuclei per blastocyst was significantly lower in mTCM (haploids, 15; diploids, 16.1) than in Whitten's medium (haploids, 35.7; diploids, 40.1; P < 0.01), suggesting that the number of nuclei in blastocysts was affected by the culture medium.

Journal Article↗
PubMed1996

Gene organization in the ada-rplL region of Streptomyces virginiae.

The gene organization of a 7.4-kb region of the Streptomyces virginiae (Sv) chromosome was determined. The predicted open reading frames (ORFs) and their predicted products, in sequence order, were (i) ada, encoding adenosine deaminase [EC 3.5.4.4], (ii) aat, encoding a protein homologous to aspartate aminotransferase [EC 2.6.1.1], (iii) secE, encoding a protein involved in protein secretion, (iv) vbrA, encoding a NusG-like protein involved in antitermination of transcription as described by Okamoto et al. [J. Biol. Chem. 267 (1992) 1093-1098], and (v) rplKAJL, encoding the large subunits of the ribosomal proteins L11, L1, L10 and L12. Six of the ORFs (secE-rplL) were oriented in the same direction, but the other two (ada and aat) had the opposite orientation. The gene organization of the secE-rplL region in Sv was identical to that in Escherichia coli.

Adenosine Deaminase↗
PubMed1996

Enhancement of SPARC (osteonectin) synthesis in arthritic cartilage. Increased levels in synovial fluids from patients with rheumatoid arthritis and regulation by growth factors and cytokines in chondrocyte cultures.

OBJECTIVE: To investigate the roles of SPARC (secreted protein, acidic and rich in cysteine) (osteonectin) in arthritis, using cartilage and synovium specimens and synovial fluids (SF) from patients with rheumatoid arthritis (RA) or osteoarthritis (OA), and to examine the effects of cytokines, growth factors, and hormones on SPARC synthesis by chondrocytes in culture. METHODS: SPARC in cartilage and synovium was immunostained with monoclonal antibodies. SPARC synthesis by cultured chondrocytes was measured by Northern blot analysis, immunoblotting, and sandwich enzyme-linked immunosorbent assay. RESULTS: SPARC was identified in numerous chondrocytes in the superficial and middle zones and in regenerating chondrocytes of RA and OA joints, whereas such staining was absent in these zones of normal cartilage, except for weak signals from a few chondrocytes in the deep zone. In addition, SPARC synthesis was enhanced in synovial cells of RA and OA joints. The average SPARC level in SF was 10-fold higher in the RA than in the OA population. In rabbit articular chondrocyte cultures, administration of transforming growth factor beta 1 (TGF beta 1) and bone morphogenetic protein 2 increased SPARC levels at 24-48 hours, whereas interleukin-lbeta (IL-1 beta), IL-1 alpha, tumor necrosis factor alpha, lipopolysaccharide, phorbol myristate acetate, basic fibroblast growth factor, and dexamethasone decreased SPARC levels at 24-72 hours. TGF beta increased SPARC messenger RNA (mRNA) levels at 24 hours, whereas IL-1 beta caused a marked decrease in SPARC mRNA levels at 24 hours. Furthermore, IL-1 decreased the glycosylation of SPARC. CONCLUSION: These findings suggest that various growth factors and cytokines, including TGF beta 1 and IL-1 beta, regulate the production of SPARC by chondrocytes at pre- and posttranslational levels, and that SPARC synthesis is markedly enhanced in arthritic joints.

Adult↗
PubMed1996

Oxidation of D(-)3-hydroxybutyrate administered to rats with extensive burns.

Although the suppressive effect of 3-hydroxybutyrate (3-OHB) on post-traumatic protein catabolism in traumatized patients is well documented, the oxidation of exogenously administered 3-OHB during catabolic stress has not been investigated. The present study was designed to evaluate, using radioactive isotopes, total body oxidation in rats with and without burn stress to which 3-OHB had been exogenously administered, in comparison with total body oxidation in such rats that had received glucose. The rats were divided into four groups, based on whether or not a 30% full-thickness burn was inflicted, and the type of infusate they received after the burn, namely, 3-OHB or glucose. The total exhaled CO2 was collected for 6h after the infusion was commenced, and 14CO2 was assayed in a liquid scintillation spectrometer. Oxidation of the infusate was calculated from the percentage of exhaled 14CO2 derived from the infused substrates. The plasma concentration of 3-OHB was significantly increased after the infusion in both the burned and non-burned rats. The total exhaled 14CO2 from the rats infused with glucose decreased from 48.2 +/- 2.4% to 40.8 +/- 3.7% (means +/- SD, P < 0.001) after thermal injury. However, the total exhaled 14CO2 from the rats infused with 3-OHB appeared sooner, and there was no difference in the total expired 14CO2 derived from 3-OHB between the burned and non-burned rats, at 68.1 +/- 2.7% vs 66.4 +/- 3.4%, respectively. These findings suggest that even under conditions of burn stress, 3-OHB can be oxidized normally if the plasma concentration of 3-OHB is elevated by exogenous administration.

3-Hydroxybutyric Acid↗
PubMed1996

Assessment of sexual orientation in lesbian/gay/bisexual studies.

This article provides a critical review of various methods for assessing sexual orientation in previous lesbian/gay/bisexual studies. A content analysis of 144 lesbian/gay/bisexual studies published in the Journal of Homosexuality (Volumes 1 to 24; 1974-93) was conducted by two independent reviewers. Findings suggest that women and bisexuals were underrepresented, and, in about one third of the studies, participants' sexual orientations were assumed rather than assessed. Five methods for the assessment of sexual orientation were identified, with self-identification (as heterosexual/homosexual/bisexual/lesbian/gay) the most typical. Each assessment method was critically examined and a 2-by-2 multidimensional assessment model was suggested for use in lesbian/gay/bisexual studies.

Bisexuality↗
PubMed1996

Clinical implications of renal cyst in primary aldosteronism.

The present study surveyed 69 patients with aldosteronoma to study the clinical implications of renal cysts demonstrated in computed tomography. Patients who had cysts (n = 16, 23.2%) were older and had a longer duration of hypertension and more severe hypokalemia than those without cysts (n = 53). Patients with cysts therefore had longer-term, more severe hypokalemia than those without cysts. Endogeneous creatinine clearance (Ccr), measured in 61 patients, was significantly lower in patients with cysts (58.4 +/- 7.1 ml/min, n = 16) than in those without cysts (77.3 +/- 7.1 ml/min, n = 45, P = 0.0039). This significant difference was observed even after adjusting for covariables (age, duration of hypertension, and serum potassium) between the two groups by analysis of covariance (ANCOVA). No significant difference was observed in gender, blood pressure, serum creatinine, plasma aldosterone, or PRA. Age, serum potassium levels, and systolic and diastolic blood pressure were the significant determinants in predicting Ccr in a backward stepwise multiple regression analysis (r = 0.505, n = 61, P = 0.0025). Cysts were graded into four classes on the basis of number and size. Cyst grading correlated negatively with Ccr at a Spearman rank correlation (rho = -0.33, n = 61, P = 0.0103). The incidence of chronic renal failure was significantly higher in patients with cysts (18.8%) than in patients without (0%) in a Fischer's exact probability test (P = 0.0107). Thus, both renal cysts and dysfunction arose and/or developed from common roots, i.e., the duration and severity of hypokalemia, in primary aldosteronism. In addition, we surveyed 27 patients with pheochromocytoma. Patients with renal cysts (n = 8) had a significantly longer duration of hypertension than those without cysts. No significant difference was observed in Ccr between patients with and those without cysts. Thus, a significant link between renal cysts and Ccr was a specific feature of primary aldosteronism, but not of pheochromocytoma. In summary, the renal cysts in primary aldosteronism should be recognized as a significant complication representing the extent of renal injury and dysfunction.

Adolescent↗
PubMed1996

LH and testosterone modulate mercuric chloride-induced acute renal failure in male rats: the implication of stress-induced hypogonadism.

The significance of stress-induced hypogonadism remains unclear. Since plasma testosterone and LH have renotropic activity that is other than reproductive, we hypothesize that stress-induced hypogonadism is an adaptive response to protect the kidney. To examine this hypothesis, we prepared hypogonadal male rats with different levels of LH and testosterone through orchiectomy (castration), through chronic treatment with a slowly secreted form of gonadotropin-releasing hormone agonist (GnRHA; GnRHA pretreatment), or through both treatments concomitantly (castration with GnRHA pretreatment). Castrated rats had undetectable plasma testosterone and high plasma LH. GnRHA-pretreated rats had low plasma testosterone and normal plasma LH. Castrated rats with GnRHA pretreatment had undetectable plasma testosterone and normal plasma LH. We compared their sensitivity to HgCl2 nephrotoxicity and found that, when a low dose of HgCl2 (1.5 mg/kg body weight (BW)) was injected s.c. to induce acute renal failure, endogenous creatinine clearance (Ccr) decreased from 390 +/- 30 to 94 +/- 17 ml/h per kg BW in intact (unpretreated) rats. Such a decrease in Ccr was completely prevented in castrated rats (388 +/- 30 ml/h per kg BW) and partially prevented in GnRHA-pretreated rats (216 +/- 40 ml/h per kg BW). When a high dose of HgCl2 (2.25 mg/kg BW) was injected, half of the eight intact rats died but castrated rats and GnRHA-pretreated rats survived (P < 0.05). The elevated resistance in castrated rats was reduced when plasma LH was reduced with GnRHA pretreatment, but was restored by additional pretreatment with ovine LH (40 micrograms/day), as evidenced by changes in Ccr. Elevated resistance in castrated rats was also reduced by the administration of testosterone propionate. In conclusion, hypogonadism activated the preventive and defensive mechanisms that protect the kidney through both decreased plasma testosterone and high or even normal plasma LH.

Acute Kidney Injury↗
PubMed1996

[The relationship between self-esteem and self-disclosure of negative information].

Although self-disclosure after a negative experience may be good for our adjustment, we also feel hesitant to do so. This study investigated the relationship between self-esteem and hesitancy to disclose negative information about one's self. One hundred and fifty-five undergraduates imagined self-disclosure to a friend of high or low intimacy. They then answered a questionnaire concerning hesitancy to self-disclose negative information to friends, as well as expected negative consequences of such self-disclosure. Main results were: (1) Low intimacy strongly affected the hesitancy. (2) Factor analysis of the negative consequences found three factors: interpersonal and intra-personal negative-effect, and no positive expectation. (3) Hesitancy of high self-esteem students was most affected by the interpersonal factor. Impression management may be the reason. (4) On the other hand, low students tended to feel hurt after negative self-disclosure. Theirs was affected by the intra-personal and no positive expectation factors. Defensiveness may be the reason. The results were discussed from the viewpoint of adjustment when people have had a negative experience.

Adult↗
PubMed1996

Spontaneous complete necrosis of hepatocellular carcinoma.

We report a 69-yr-old female with a liver mass which, when surgically resected, was believed to be the spontaneous complete necrosis of hepatocellular carcinoma. The preoperative level of alpha-fetoprotein was high at 1050 ng/ml, and the mass was grossly an encapsulated nodular lesion with septa. Histologically, no viable tumor cells were demonstrated. The alpha-fetoprotein level decreased to a normal range. The postoperative course was uneventful, and the patient is alive and well 1 yr after surgery.

Aged↗
PubMed1996

[Hepatic arterial perfusion scintigraphy with 99mTc-MAA for assessment of the hepatic distribution of drugs given by intrahepatic arterial infusion].

Twenty-six hepatic arterial perfusion studies using 99mTc-MAA were carried out in 21 patients who underwent hepatic arterial infusion chemotherapy. Inhomogeneous perfusion of the liver area supplied by the artery in which the catheter was placed was seen in 11 (42%) of 26 studies, which may be caused by poor mixing of drug with blood at infusion site. To evaluate whether pulsed arterial infusion reduces this phenomenon, 99mTc-MAA was injected with pulsatile infusion in studies. Improved RI distribution of the liver was obtained in 2 of 15 with pulsatile infusion. Extrahepatic perfusion was noted in 6 (23%) of 26 studies. Displaced catheter was demonstrated in 3 (12%) of 26 studies. Despite the attempts to correct the arterial abnormalities to ensure homogeneous perfusion of the liver in 4 patients with anatomic variants, inhomogeneous perfusion was seen in 3 of 4 patients. Hepatic arterial perfusion scintigraphy by 99mTc-MAA has advantages for assessing intrahepatic distribution of the chemotherapeutic agents, in addition to helping to avoid clinical complications caused by extrahepatic perfusion.

Adult↗
PubMed1996

Does bone SPECT actually have lower sensitivity for detecting vertebral metastasis than MRI?

UNLABELLED: We compared the ability of bone SPECT and MRI to detect vertebral metastasis. METHODS: Skeletal scintigraphy, including planar and SPECT imaging, and spinal MRI examinations, were performed in 22 cancer patients in whom a total of 88 metastatic foci and 12 degenerative joint disease lesions were detected. Metastatic foci were defined as lesions that suggested metastasis on MRI and/or bone destruction on radiographs or CT and/or aggravation of increased tracer uptakes on serial bone scans. Image reconstruction of axial, coronal and sagittal sections was processed in a 128 X 128 matrix. MRI studies were performed with a 1.5 tesla signal scanner using fast spin-echo sequences. T1- and T2-weighted images were obtained in the sagittal plane. RESULTS: Twenty patients had at least one vertebral metastasis. MRI diagnosed 86 of the 88 (97.7%) metastatic foci; bone SPECT correctly diagnosed 81 of 88 (92.0%); and planar imaging detected 62 of 88 (70.4%). The two vertebrae with metastasis not detected by MRI were clearly seen by bone SPECT. Extra-vertebral body metastases (e.g. in the pedicle, lamina, transverse and spinous processes) were, however, most often detected by SPECT, followed by MRI and planar imaging (40 versus 32 versus 4). CONCLUSION: Vertebral SPECT, using high-resolution SPECT equipment, produced excellent results that were comparable to and complementary with MRI in detecting vertebral metastasis. Our data suggest that vertebral SPECT is superior to MRI in detecting extra-vertebral body metastasis.

Adolescent↗
PubMed1996

Effect of photic conditioning on blink reflex recovery function in blepharospasm.

Patients with blepharospasm may have selective sensitivity to photic stimuli, for their symptoms are often aggravated after exposure to brightness. To investigate the pathophysiology underlying this phenomenon, we compared the effects of electric and photic conditioning on electrically-evoked blink reflex in 21 patients with blepharospasm and 11 age-matched control subjects. With electric conditioning, R1 was facilitated at inter-stimulus intervals (ISIs) of up to 100 ms in both groups. R2 was inhibited at all ISIs longer than 20 ms in the normals, but to a much lesser extent in the patients, suggesting increased excitability of the multi-synaptic reflex pathway. Compared to electric conditioning, photic conditioning was less potent in inhibiting R2 in the normals. In contrast, photic conditioning in the patients produced R2 inhibition as powerful as electric conditioning. These findings indicate that, in patients with blepharospasm, photic input has a relatively more profound inhibitory effect on the test blink reflex than electric conditioning as compared with normal subjects. The greater susceptibility of the brainstem interneurons to photic conditioning in blepharospasm may be related to the clinically-observed light sensitivity.

Adult↗
PubMed1996

A novel regulatory epitope defined by a murine monoclonal antibody to the platelet GPIIb-IIIa complex (alpha IIb beta 3 integrin).

We characterized a murine monoclonal antibody, PT25-2 (IgG1), raised against washed human platelets. The antibody and its Fab fragments were both capable of inducing platelet aggregation in a fibrinogen-dependent manner and induced 125I-fibrinogen binding to unstimulated platelets (120,000 molecules/platelet at a 100 nM IgG concentration). The antibody immunoprecipitated the alpha IIb beta 3 complex from lysates of iodinated platelets but did not react with the respective subunits when complex formation was disrupted by treatment with 5 mM EDTA at 37 degrees C for 30 min. However, simply removing the extracellular divalent cation with EDTA had no effect on antibody binding indicating that the antibody's epitope depends upon a conformational structure maintained by alpha beta subunit association. Antibody binding to unstimulated, washed platelets yielded binding parameters (Kd = 40 nM, Bmax = 100,000 molecules/platelet), which were found to be virtually unchanged when binding was performed using thrombin or RGDS-peptide-stimulated platelets. Thus, the PT25-2 antibody defines a novel regulatory epitope expressed by the alpha IIb beta 3 integrin on unstimulated, quiescent platelets.

Animals↗