Search PubMed⌕ Search

Biomedical subjects

S Katayama

Publications and source records attributed to S Katayama.

At least 109 records · Page 6Linked to original sources
PubMed1999

Clinical usefulness of telomerase activity and telomere length in the preoperative diagnosis of gastric and colorectal cancer.

It has been reported that telomerase activity and telomeric reduction can be detected in many human cancers. Although it is well known that telomerase activity and telomere length have important implications for cancer biology, their clinical usefulness in the preoperative diagnosis of gastric and colorectal cancer has not been elucidated. Therefore, we examined telomerase activity and telomere length in gastric and colorectal cancer using tissue samples obtained by fiberscopy. Telomerase activity was measured by a telomeric repeat amplification protocol (TRAP). Although telomerase activity was detected in 1/12 (8%) cases of gastric polyp and in 2/9 (22%) cases of colorectal polyp, its positivity in gastric cancer and colorectal cancer was 7/10 (70%) and 21/26 (81%; P<0.0003 and P<0.0001, respectively). Telomere length was analyzed by Southern blotting, and telomeric reduction in gastric cancer was significantly greater than that in gastric polyp (P<0.0003). However, there was no telomeric reduction between colorectal cancer and colorectal polyp. The results of the present study indicate that determination of telomerase activity and telomere length may serve as a useful method for preoperative diagnosis of gastric and colorectal cancer.

Adult↗
PubMed1999

Cyclopropenone-containing cysteine proteinase inhibitors. Synthesis and enzyme inhibitory activities.

By focusing on the amphiphilic properties of cyclopropenone (e.g. a good electrophile and a precursor for a stable 2pi-aromatic hydroxycyclopropenium cation), a new class of cysteine proteinase inhibitors containing a cyclopropenone moiety was designed. For the purpose of the present research, we needed to devise a new method to introduce a peptide-related moiety as a substituent on the cyclopropenone residue. We investigated the reaction of metalated cyclopropenone acetal derivatives (2, R2 = metal) with N-protected alpha-aminoaldehydes 4 to obtain the adduct 5, and succeeded in the preparation of highly potentiated cysteine proteinase inhibitors 8 after several steps transformations. They showed strong inhibitory activities only to cysteine proteinases such as calpain, papain, cathepsin B, and cathepsin L and not to serine (e.g. thrombin and cathepsin G) and aspartic proteinases (e.g. cathepsin D). Kinetic studies indicated that they are competitive inhibitors, and by the examinations of their inhibitory mechanism it became clear that they are reversible inhibitors.

Calpain↗
PubMed1999

A case of nocturnal polyuria in olivopontocerebellar atrophy.

We report a case of olivopontocerebellar atrophy without sleep apnea syndrome who presented nocturnal polyuria. It is considered that a disturbance in the circadian rhythm for arginine vasopressin secretion due to degeneration of suprachiasmatic nuclei and marked increase in the secretion of atrial natriuretic peptide due to abnormal diurnal variation in blood pressure may be involved in the mechanism of nocturnal polyuria.

Arginine Vasopressin↗
PubMed1999

Disappearance of rhythmic involuntary movements during sleep in a case of olivopontocerebellar atrophy.

We report on a 54-year-old woman with an 8 or so year history of olivopontocerebellar atrophy associated with the rhythmic involuntary movements of the left upper and lower limbs, and cervical region. Surface electromyogram of the left upper limb revealed rhythmicity (about 3 Hz) and reciprocity between antagonistic muscles, which disappeared on polysomnography at all sleep stages including rapid eye movement sleep without atonia. These were characterized by the co-existence of rhythmic skeletal myoclonus and parkinsonian tremor. These findings suggest that a disturbance of the striatonigral system as well as the dentato-rubro-olivary circuit may be involved in these movements. It also seems that their fate is dependent on the level of wakefulness and that the ascending reticular activating system also plays a role in the development of these movements.

Cerebellar Nuclei↗
PubMed1999

Autonomic function in the early stage of panic disorder: power spectral analysis of heart rate variability.

Previous studies of autonomic nervous system (ANS) function in panic disorder (PD) patients have yielded conflicting results. We speculate that these differences might result from the variety of clinical stages of PD. In order to investigate this, we compared ANS activity in untreated patients in the early stage of PD with control subjects using power spectral analysis of electrocardiogram R-R intervals (PSR-R) in supine rest and during head-up tilt, which was performed according to the maximum entropy method (MEM). It recognizes two main components: high-frequency power (HF), which mainly reflects cardiac parasympathetic activity, and low-frequency power (LF), which reflects both cardiac sympathetic and parasympathetic activity. The patients with PD had significantly higher values for all components of PSR-R only in tilt position total power (TP), LF, and HF than did the control subjects (P<0.01, <0.01, <0.02, respectively). However, the LF/HF ratio which indicated sympathovagal balance did not differ significantly between the two groups in tilt position. Our findings suggest that patients with PD in the early stage of illness have co-activation of sympathetic and parasympathetic nervous systems, which might act to maintain a balance between the two autonomic systems.

Adult↗
PubMed1999

Inhibition of hepatocellular carcinoma by glycyrrhizin in diethylnitrosamine-treated mice.

Glycyrrhizin (GL) is widely used in Japan as a therapeutic agent for chronic active liver diseases. However, its action on hepatocarcinogenesis remains to be elucidated. To clarify its effect, mice treated with diethylnitrosamine (NDEA) with or without GL were analyzed. Five-week-old male BALB/c mice were divided into two groups, GL (n=50) and C (n=47). Mice in the GL group intramuscularly received 2 mg of GL 3 days a week, and mice in the C group received the same volume of saline in the same way. After 2 weeks, the mice were treated with an i.p. injection of 75 mg/kg body wt of NDEA weekly for 3 weeks and 100 mg/kg body wt of NDEA weekly for the following 3 weeks. Thirty additional mice that did not receive NDEA treatment were divided into two groups, GC (n=15) and SC (n=15). They received GL or saline, respectively. Mice in the 4 groups were killed every 5 weeks after the last injection of NDEA from 7 weeks to 32 weeks. Liver function tests such as AST and albumin were significantly improved in the GL group compared with the C group (P < 0.05, each). Although liver nodules appeared in the C group at 22 weeks, they were not observed until 32 weeks in the GL group. At 32 weeks, the mean number of liver tumors, composed of adenoma and hepatocellular carcinoma (HCC), in the GL group was 0.71, which was significantly decreased compared with 1.64 of the C group (P < 0.05). The mean number of HCC in the GL group was 0.29/liver, which was lower than 0.82/liver in the C group (P < 0.05). The incidence rate of HCC at 32 weeks was 64% in the C group and 21% in the GL group (P < 0.05, C versus GL group). Our results suggest that GL treatment inhibits the occurrence of HCC.

Adenoma↗
PubMed1999

Clinicopathological significance of poorly differentiated thyroid carcinoma.

The clinicopathological importance of a heterogeneous group of poorly differentiated thyroid carcinomas is not fully understood. Using data obtained from 303 surgically treated patients with differentiated thyroid carcinomas, the correlations between the aggressive histologic features and the clinicopathological findings, postoperative recurrences, and prognosis were retrospectively examined. In 201 cases, the carcinomas were well differentiated. The remaining 102 cases of poorly differentiated carcinomas were divided into two groups: focal-poorly differentiated (<10%) and diffuse-poorly differentiated (> or = 10%) carcinomas according to the extent of the poorly differentiated component. These poorly differentiated carcinomas were associated with high age (focal-poorly differentiated and diffuse-poorly differentiated versus well differentiated: 55 years and 59 versus 49; p < 0.0001), frequent presence of lymph node metastases (70% and 66% versus 48%; p = 0.0099) and distant metastases at diagnosis (11% and 11% versus 2%; p = 0.0098), and extrathyroidal invasion (53% and 53% versus 21%; p < 0.0001). There was independent correlation with age and the presence of extrathyroidal invasion. Cases of diffuse-poorly differentiated carcinomas showed frequent relapse (diffuse-poorly differentiated versus focal-poorly differentiated and well differentiated: 45% versus 30% and 24%; p = 0.0062) and poor prognoses (mean survival period = 9.15 versus 19.03 and 20.87 years; p < 0.0001) compared with the well and focal-poorly differentiated carcinomas. These data suggest that diffuse-poorly differentiated carcinoma is an important clinicopathological entity.

Adenocarcinoma, Follicular↗
PubMed1999

A Clostridium perfringens hem gene cluster contains a cysG(B) homologue that is involved in cobalamin biosynthesis.

The hem gene cluster, which consists of hemA, cysG(B), hemC, hemD, hemB, and hemL genes, and encodes enzymes involved in the biosynthetic pathway from glutamyl-tRNA to uroporphyrinogen III, has been identified by the cloning and sequencing of two overlapping DNA fragments from Clostridium perfringens NCTC8237. The deduced amino acid sequence of the N-terminal region of C. perfringens HemD is homologous to those reported for the C-terminal region of Salmonella typhimurium CysG and Clostridium josui HemD. C. perfringens CysG(B) is a predicted 220-residue protein which shows homology to the N-terminal region of S. typhimurium CysG. Disruption of the cysG(B) gene in C. perfringens strain 13 by homologous recombination reduced cobalamin (vitamin B12) levels by a factor of 200. When grown in vitamin B12-deficient medium, the mutant strain showed a four-fold increase in its doubling time compared with that of the wild-type strain, and this effect was counteracted by supplementing the medium with vitamin B12. These results suggest that C. perfringens CysG(B) is involved in the chelation of cobalt to precorrin II as suggested for the CysG(B) domain of S. typhimurium CysG, enabling the synthesis of cobalamin.

Base Sequence↗
PubMed1999

Gene duplication and multiplicity of collagenases in Clostridium histolyticum.

Clostridium histolyticum collagenase contains a number of different active components. Previously we have shown that colH encodes a 116-kDa collagenase (ColH) and a 98-kDa gelatinase. We purified a different 116-kDa collagenase (ColG) from the culture supernatant and sequenced its gene (colG). We also identified four other gelatinases (105, 82, 78, and 67 kDa) and determined their N-terminal amino acid sequences, all of which coincided with that of either ColG or ColH. Hybridization experiments showed that each gene is present in a single copy and each gene is transcribed into a single mRNA. These results suggest that all the gelatinases are produced from the respective full-length collagenase by the proteolytic removal of C-terminal fragments. The substrate specificities of the enzymes suggest that colG and colH encode class I and class II enzymes, respectively. Analysis of their DNA locations by pulsed-field gel electrophoresis and nucleotide sequencing of their surrounding regions revealed that the two genes are located in different sites on the chromosome. C. histolyticum colG is more similar to C. perfringens colA than to colH in terms of domain structure. Both colG and colA have a homologous gene, mscL, at their 3' ends. These results suggest that gene duplication and segment duplication have occurred in an ancestor cell common to C. histolyticum and C. perfringens and that further divergence of the parent gene produced colG and colA.

Amino Acid Sequence↗
PubMed1999

Identification of metal ligands in the Clostridium histolyticum ColH collagenase.

A Clostridium histolyticum 116-kDa collagenase has an H415EXXH motif but not the third zinc ligand, as found in already characterized zinc metalloproteinases. To identify its catalytic site, we mutated the codons corresponding to the three conserved residues in the motif to other amino acid residues. The mutation affecting His415 or His419 abolished catalytic activity and zinc binding, while that affecting Glu416 did the former but not the latter. These results suggest that the motif forms the catalytic site. We also mutated the codons corresponding to other amino acid residues that are likely zinc ligands. The mutation affecting Glu447 decreased markedly both the enzymatic activity and the zinc content, while that affecting Glu446 or Glu451 had smaller effects on activity and zinc binding. These mutations caused a decrease in kcat but no significant change in Km. These results are consistent with the hypothesis that Glu447 is the third zinc ligand. The spacing of the three zinc ligands is the same in all known clostridial collagenases but not in other known gluzincins, indicating that they form a new gluzincin subfamily. The effects of mutations affecting Glu446 and Glu451 suggest that the two residues are also involved in catalysis, possibly through an interaction with the two zinc-binding histidine residues.

Amino Acid Sequence↗
PubMed1999

Possible neural mechanisms involved in footshock stress-induced enhancement of exploratory behavior in mice.

The effect of inescapable footshock stress on open-field activity, as measured by the number of ambulations, was studied in male mice. Ambulations significantly increased after footshock stress, the most significant effect appeared after 20 min-stimulation and the effect decreased as footshock time lengthened. The footshock stress-induced enhancement of ambulation was inhibited by haloperidol (0.2, 0.5 and 1 mg/kg), phentolamine (5 and 10 mg/kg), mianserin (20 mg/kg), atropine (0.5, 1 and 2 mg/kg), naltrexone (10 mg/kg) and MK-801 (0.05, 0.1 and 0.2 mg/kg), but was not influenced by propranolol (5, 10 and 20 mg/kg) or diazepam (1, 2 and 5 mg/kg). Haloperidol (0.5 and 1 mg/kg) and mianserin (5, 10 and 20 mg/kg) also exerted an inhibitory effect on non-stressed normal mice. These results suggest that dopaminergic, alpha-adrenergic, cholinergic, opioidergic and N-methyl-D-aspartate (NMDA) receptor-mediated neurotransmission systems are involved in the footshock stress-induced ambulatory activation.

Animals↗
PubMed1999

Rationale for time-qualified reference standards for 24-hour blood pressure values and their circadian rhythms in Japanese normotensive adults: a study by the Ambulatory Blood Pressure Monitoring Research Group.

The aim of this study was to demonstrate that blood pressure (BP) has to be standardized according to its circadian variability, including the properties shown in its circadian rhythm. The BP time-qualified standards were derived from a sample of 644 clinically healthy normotensive Japanese subjects (320 males, 324 females; age range, 18-93 years), stratified by age-group and gender, who underwent noninvasive ambulatory monitoring according to a fixed protocol. The monitored data series shows that BP exhibits a within-day variability at any age of life in both males and females. Additionally, the monitored data series shows that BP exhibits a significant circadian rhythm at any age of life in both males and females. The age- and sex-related reference limits for the BP within-day variability constitute the time-qualified standards against which both the casual and monitored BP measurements can be compared in order to detect whether or not they are compatible with normotension. The reference limits for the BP circadian rhythm represent the rhythmometric standards against which the BP oscillatory curve can be compared in order to detect whether or not they are compatible with a physiological circadian rhythm.

Adolescent↗
PubMed1999

A new quantitative method for rabies virus by detection of nucleoprotein in virion using ELISA.

We have developed a new quantitative method for rabies virus (RV) detection using enzyme-linked immunosorbent assay (ELISA). The method named N-ELISA was based on the quantitation of nucleoprotein (N) in RV virions captured by RV-specific polyclonal antibodies on an ELISA plate. Both infective and defective interfering (DI) particles of RV could be detected by this method. When viruses were propagated in a medium of pH 7.4 adjusted with 7% NaHCO3, N-ELISA could detect them with titers of more than 10(6) pfu/ml, though the result did not correlate highly with that of the infectivity assay. The reason for this was considered to be that RVs included spikeless and damaged particles which were produced under conditions of low or high pH. However, in the time course of virus yield, titers of N-ELISA correlated well with those of the infectivity assay.

Animals↗
PubMed1999

Hypercalcemia accompanied by hypothalamic hypopituitarism, central diabetes inspidus and hyperthyroidism.

We present here a case of prominent hypercalcemia accompanied by hypothalamic tumor and Graves' disease. A 24-year-old man with hypothalamic tumor showed hypopituitarism, central diabetes inspidus (DI) and hyperthyroidism. Nausea, loss of thirst and appetite, and general fatigue were found with the unveiling of hypercalcemia and hypernatremia. Parathyroid hormone (PTH) and 1alpha-dihydroxyvitamin D levels were suppressed with a normal range of PTH-related protein values. One-desamino-(8-D-arginine)-vasopressin (DDAVP) and half-saline administration normalized hypernatremia, while hypercalcemia was still sustained. Administration of cortisone acetate and thiamazole reduced the elevated serum Ca level. In the present case, concurrent hyperthyroidism was assumed to accelerate skeletal mobilization of calcium into the circulation. Hypocortisolism and central DI was also considered to contribute, to some extent, to the hypercalcemia through renal handling of Ca.

Adult↗
PubMed1999

Troglitazone and metformin, but not glibenclamide, decrease blood pressure in Otsuka Long Evans Tokushima Fatty rats.

To determine whether hypoglycemic agents such as sulfonylureas, biguanides and the newly developed insulin sensitizers such as troglitazone, have hypotensive effects in an animal model of non-insulin-dependent diabetes mellitus associated with insulin resistance, male Otsuka Long Evans Tokushima Fatty (OLETF) rats aged 12 weeks were administered following hypoglycemic agents or vehicle by gavage for 26 weeks; glibenclamide (5 mg/kg/day), metformin (100 mg/kg/day) and troglitazone (70 mg/kg/day). The gain in body weight was similar in the different groups. At 36 weeks of age, troglitazone significantly decreased fasting plasma glucose levels when compared to controls. The area under the curve (AUC) for insulin during glucose loading (2 g/kg, i.p.) was 50% lower in the group treated with troglitazone. Serum triglyceride levels in troglitazone-treated rats were also significantly lower than in the glibenclamide-treated group. Plasma membrane GLUT4 protein content was significantly augmented by a factor of 1.48-fold (p<0.02) in the glibenclamide-treated group and tended to be increased 1.32 times by administration of metformin (p=0.06). The systolic blood pressure increased with age in controls and the glibenclamide-treated group. In contrast, treatment with either metformin or troglitazone significantly decreased systolic blood pressure after the age of 29 weeks. Plasma norepinephrine and epinephrine concentrations did not show a significant decrease in the treated group when compared with the control group. These results suggest that metformin and troglitazone, but not glibenclamide, lower blood pressure in an animal model of insulin resistance, providing further evidence of the beneficial effect of insulin sensitizing hypoglycemic agents on blood pressure.

Animals↗
PubMed1999

[Association of silent cerebral infarction with cerebral hemispheric--sub-tentorial infarction in patients with supra-nuclear dysarthria or dysphagia].

Little information is available concerning the latent effects of silent cerebral infarction (SCI) on dysarthria (DA), dysphagia (DP), or both. A detailed analysis of MR images of multiple cerebral infarction was carried out to determine whether SCI is associated with the development of DA or DP. In this study MR images of the supra- and sub-tentorial regions were obtained from 14 patients presenting with persistent DA and DP (DA + DP group) and 9 patients presenting with DA alone (DA group) after the first episode of cerebral infarction. The DA + DP inducing lesion was identified from the change in signal intensity and the side with symptoms in 6 patients. Involvement of 3 lesions of the bilateral cortical branches, striatum, and pons on the line connecting the contra-lateral SCI with the lesion were noted in 4 patients (67%, vs. 40% for the DA group). Latent association of SCI with the development of supra-nuclear DA and DP was noted in 1 patient each from the DA + DP and DA groups. The results of this study support the concept that SCI patients include those in which SCI is involved in the development of supra-nuclear DA or DP, and suggest that SCI should be treated.

Aged↗
PubMed1999

[A case of chordoid meningioma].

Chordoid meningioma is a very rare variant, especially in adults. We report an adult case of chordoid meningioma. A 52-year-old man was admitted to our hospital due to right hemiparesis. MRI revealed a left temporal convexity mass that showed two structures; the cerebral layer was shown as an isointensity area on T1WI and T2WI, and the dural layer seemed relatively hypointense on T1WI and hyperintense on T2WI. The tumor was well enhanced with gadolinium, especially on the dural side. A left external carotid arteriogram showed tumor stains with feeding vessels from the left middle meningeal artery. The tumor was totally removed via fronto-temporal craniotomy. Histological examination of the surgical specimen revealed two different structural components, meningothelial meningioma on the cerebral side, and chordoid meningioma on the dural side, consisting of clustering spindled cells and partly vacuolated ones in the mucoid stroma. In immunohistochemical examination, tumor cells showed positive staining for vimentin and epithelial membrane antigen (EMA), and negative for cytokeratin. From the above findings, this case was diagnosed as chordoid meningioma in an adult, a very rare variant of meningioma.

Chordoma↗