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K Ochi

Publications and source records attributed to K Ochi.

At least 55 records · Page 3Linked to original sources
PubMed1998

Comparative ribosomal protein (L11 and L30) sequence analyses of several Streptomyces spp. commonly used in genetic studies.

The taxonomic relationships among nine strains of Streptomyces, which have been commonly used for genetic studies, were examined by sequence analysis of their ribosomal L11(= rplK) protein genes. Phylogenetic relationships among these organisms derived from similarity sequence analysis of the rplK genes were in good agreement with those derived from the analysis of the deduced L11 protein amino acid sequence itself, indicating complete sequence homology among Streptomyces coelicolor A3(2), 'Streptomyces lividans 66' and Streptomyces violaceoruber JCM 4423. S. coelicolor A3(2) related (in the order of closer relatedness) to Streptomyces antibioticus ATCC 14888, Streptomyces griseus IFO 13189, Streptomyces lavendulae MA 406 A-1 and Streptomyces virginiae MAFF 6014. Sequence analysis of the 26 N-terminal amino acid residues of ribosomal L30 proteins also resulted in similar phylogenetic relationships, except that S. griseus, S. lavendulae and S. virginiae were not differentiated from each other using this method. These findings concerning the phylogenetic relationship therefore confirm the previous conclusion that S. coelicolor A3(2), 'S. lividans 66' and S. violaceoruber should be recognized as a single taxon at the species level.

Amino Acid Sequence↗
PubMed1998

A case of small pancreatic cancer diagnosed by serial follow-up studies promptly by a positive K-ras point mutation in pure pancreatic juice.

We report a 74-yr-old woman who was referred to our hospital because of abdominal fullness. ERP showed a questionable irregularity of the main pancreatic duct at the body. Examination of pure pancreatic juice was positive for K-ras point mutation at codon 12 and negative for cytology. Because neither US nor CT showed apparent lesions in the pancreas, we decided to follow up the patient with serial ERP and pure pancreatic juice studies at 3-month intervals. No changes had been seen up to 18 months later, when cytology was conclusive for malignancy with an apparent stenosis of the main pancreatic duct at the body. Distal pancreatectomy with splenectomy was performed. A round mass, 12 mm in diameter, was found in the body, which proved to be an adenocarcinoma at histological examination. No extrapancreatic extension and metastases were noted. Although positive K-ras point mutation has been reported in some cases of adenoma or mucinous cell hyperplasia of the pancreas and chronic pancreatitis, our case, along with previous reports, indicated the importance of testing K-ras point mutation in pure pancreatic juices for the diagnosis of pancreatic cancer at an early stage.

Adenocarcinoma↗
PubMed1998

Acquisition of certain streptomycin-resistant (str) mutations enhances antibiotic production in bacteria.

Physiological differentiation (including antibiotic production) in microorganisms usually starts when cells encounter adverse environmental conditions and is frequently accompanied by an increase in the accumulation of intracellular ppGpp. We have found that the acquisition of certain streptomycin-resistant (str) mutations enables cells to overproduce antibiotics, demonstrating an increase in productivity 5- to 50-fold greater than that of wild-type strains. The frequency of such antibiotic-overproducing strains among the str mutants was shown to range from 3 to 46%, as examined with several strains of the genera Streptomyces, Bacillus, and Pseudomonas. Analysis of str mutants from Bacillus subtilis Marburg 168 revealed that a point mutation occurred within the rpsL gene, which encodes the ribosomal protein S12, changing Lys-56 (corresponding to Lys-43 in Escherichia coli) to Asn, Arg, Thr, or Gln. Antibiotic productivity increased in a hierarchical manner depending upon which amino acid residue replaced Lys at this position. The strA1 mutation, a genetic marker frequently used for mapping, had no effect on antibiotic productivity even though it was found to result in an amino acid alteration of Lys-56 to Ile. Gene replacement experiments with the str alleles demonstrated unambiguously that the str mutation is responsible for the antibiotic overproductivity observed. These results offer a rational approach for improving the production of antibiotic (secondary metabolism) from microorganisms.

Alleles↗
PubMed1998

Alterations in ultrastructural localization of growth-associated protein-43 (GAP-43) in periodontal Ruffini endings of rat molars during experimental tooth movement.

It is known that orthodontic forces induce discomfort and/or abnormal sensation after application of an orthodontic appliance in patients, suggesting the adaptation of periodontal neural elements to environmental changes. However, no morphological data have been provided. The present study investigated, by immunoelectron microscopy, the localization of growth-associated protein-43 (GAP-43) in periodontal Ruffini endings in rat molars during experimental tooth movement. In the untreated control group, immunoelectron microscopy demonstrated that GAP-43-like immunoreactivity in the Ruffini endings was confined to the Schwann sheaths around the axon terminals, and was in neither the cell bodies of terminal Schwann cells nor the axon terminals themselves. Immunoelectron microscopic observation revealed alterations in the localization of GAP-43-like immunoreactivity in the periodontal Ruffini endings during experimental tooth movement. After 1 day of treatment, the cell bodies of the terminal Schwann cells associated with Ruffini endings appeared to contain immunoreaction products for GAP-43, and retained GAP-43-like immunoreactivity during tooth movement. From 5 to 7 days, a major population of the axoplasm of the periodontal Ruffini endings, which was immunonegative in control, filled the GAP-43 immunoreactions, showing a tendency to decrease in number later, and disappeared completely at 14 days. These findings suggest that orthodontic forces easily induce the remodeling of the mechanoreceptive Ruffini endings as well as the active tissue remodeling in a close relationship. Since the ultrastructural localization of GAP-43-like immunoreactivity was drastically changed in the Ruffini endings during tooth movement, GAP-43 functions as one of the key molecules in the remodeling of mechanoreceptive Ruffini endings during tooth movement.

Acid Phosphatase↗
PubMed1998

Gastrobiliary dysmotility in patients with chronic pancreatitis as assessed by a single noninvasive test.

We simultaneously assessed gastric emptying and gallbladder contraction after oral administration of a liquid meal by noninvasive ultrasonography in 17 patients with chronic pancreatitis (CP) and in 17 healthy controls. Gastrointestinal (GI) transit was also assessed by a noninvasive radioopaque marker method. Exocrine pancreatic function was evaluated by analyzing pure pancreatic juice and by analyzing the autonomic nervous system by cardiovascular reflex tests. Patients with CP showed impaired gallbladder contraction at 15 min and hastened gastric emptying. The cause of the former is unclear, whereas the latter was closely related with decreased pancreatic lipase output, but not with autonomic dysfunction. GI transit time did not differ between controls and patients with CP. In conclusion, we succeeded in clearly demonstrating impaired gallbladder contraction and hastened gastric emptying in patients with CP by a single noninvasive test, ultrasonography. We also revealed for the first time that hastened gastric emptying is associated with insufficient pancreatic lipase output.

Autonomic Nervous System Diseases↗
PubMed1998

[The effects of high-dose steroid therapy on sudden deafness].

The effect of high-dose steroid therapy on sudden deafness were investigated in 19 cases. A daily intravenous administration dose of hydrocortisone sodium succinate was tapered from 800 mg to 200 mg as follows; 800 mg 800 mg, 600 mg, 600 mg, 400 mg, 400 mg, 300 mg, and 200 mg. Another 19 cases, the control group, were treated with intravenous application of prednisolone, tapered from 50 mg to 10 mg in 10-mg steps and each dose applied for 3 days. There were no significant differences in the effect on hearing between the two groups as measured by three different analyses: criteria proposed by the Committee on Sudden Deafness of the Japan Health Ministry; magnitudes of improvement of mean thresholds at five frequencies from 250 Hz to 4 kHz in affected side; and the ratio of the magnitudes of improvement of mean thresholds in affected side to magnitudes of difference between the initial mean thresholds in affected side and those in contralateral side. These findings suggest that high-dose steroid therapy for sudden deafness is not so effective as it is for idiopathic facial palsy. This may be due to the difference in the mechanisms of development between the two conditions. No critical side effects were observed in our study, which would argue for the safety of our method of high-dose steroid therapy for routine clinical use. It might be advisable to conduct additional clinical studies to determine the effect of high-dose steroid therapy for sudden deafness, because our study was conducted on a small number of patients and was not double-blind or randomized.

Adolescent↗
PubMed1998

[Obesity as one of the risk factors for urolithiasis].

BACKGROUND: It is well known that many diseases may be associated with obesity resulting from an energy-rich diet, and that a westernized diet may increase the incidence of urinary stone formation. To evaluate degree of obesity, we investigated body mass index (BMI) in patients with calcium containing upper urinary stones and examined their blood with regard to lipid metabolism. METHODS: Between July 1994 and December 1995, we analyzed 332 fresh renal-stone formers (253 males and 79 females) who visited 7 hospitals located in Ehime prefecture. As a control, 949 residents older than 20 years (387 males and 562 females) of the same prefecture were also examined by the annual Ehime prefecture office report of 1994. Body mass index as degree of obesity, stone-recurrence, blood test and other complicated diseases were examined. RESULTS: In male stone formers the rate of obesity was significantly higher than that of control males (p < 0.001). The differences were seen only in their twenties and fifties. Furthermore, among male stone formers the rate of obesity was significantly higher in recurrent stone formers than in single stone formers (p < 0.05). On the other hand, in female, there was no significant difference in the rate of obesity between stone formers and controls. No difference was seen between recurrent stone formers and single stone formers. In the blood test, there was no differences in the level of calcium, phosphate and uric acid between stone formers and controls. The level of cholesterol and triglyceride in male were significantly higher in controls (p < 0.01) and there was no difference in the level of high density lipoprotein (HDL) between stone formers and controls. Among the stone formers, 48 males (20.0%) and 17 females (21.5%) had other diseases. The rate of complicated diseases was similar to that of controls and no specific diseases in the stone formers were identified. CONCLUSION: Our report suggested that obesity in male should be considered as a risk factor for calcium containing stone formation.

Adult↗
PubMed1997

Calretinin-like immunoreactivity in the Ruffini endings, slowly adapting mechanoreceptors, of the periodontal ligament of the rat incisor.

The distribution and ultrastructural localization of calretinin (CR)-like immunoreactivity (-LI) were investigated in the lingual periodontal ligament of rat incisors. Some thick nerve fibers within the nerve bundle displayed CR-LI; these CR-like immunoreactive (-IR) nerve fibers entered the alveolar half of the lingual periodontal ligament of the incisor where dendritic terminal arborization was exhibited. Thin and beaded CR-IR nerve fibers were rarely observed in the periodontal ligament. Observations of adjacent sections immunostained with protein gene-product 9.5 (PGP 9.5) revealed that most, if not all, PGP 9.5-IR nerve terminals showing a dendritic arborization expressed CR-LI. Immunoelectron microscopic observations showed that electron-opaque immunoreaction products were localized in the axoplasm of the axon terminals, except for the mitochondria, which were surrounded by Schwann sheaths and multiple-layered basal lamina. Neither cell bodies, the cytoplasmic extension of terminal Schwann cells, nor other cellular elements such as periodontal fibroblasts exhibited CR-LI. The present findings suggest that Ruffini endings, an essential mechanoreceptor in the periodontal ligament and categorized as a slowly adapting mechanoreceptor, express CR-LI, and that CR may participate in the Ca2+ homeostasis against external stimuli in the periodontal Ruffini endings.

Animals↗
PubMed1997

Immunohistochemical localization of calbindin D28k in the periodontal Ruffini endings of rat incisors.

It was examined whether calbindin D28k (CB) might be located in the rat incisor periodontal Ruffini ending, an essential mechanoreceptor in periodontal ligament, by light- and electron-microscopic immunohistochemistry. Some thick nerve fibers showing CB-like immunoreactivity (LI) entered the lingual half of the periodontal ligament of the incisor and showed the dendritic terminal arborization. Electron-dense immunoreaction products indicating CB-LI were distributed diffusely in axoplasm of the axon terminals, no mitochondria, however, were not labeled. Neither cell bodies nor cytoplasmic extensions of the terminal Schwann cells exhibited CB-LI. CB was presumed to be involved in the maintenance of Ca2+ homeostasis in the mechano-electric transduction in mechanoreceptors in the periodontal ligament.

Animals↗
PubMed1997

Molecular and functional analysis of the ribosomal L11 and S12 protein genes (rplK and rpsL) of Streptomyces coelicolor A3(2).

A RelC deletion mutant, KO-100, of Streptomyces coelicolor A3(2) has been isolated from a collection of spontaneous thiostrepton-resistant mutants. KO-100 grows as vigorously as the parent strain and possesses a 6-bp deletion within the rplK, previously termed relC. When the wild-type rplK gene was propagated on a low-copy-number vector in mutant KO-100, the ability to produce ppGpp, actinorhodin and undecylprodigiosin, which had been lost in the RelC mutant, was completely restored. Allele replacement by gene homogenotization demonstrated that the RelC mutation is responsible for the resistance to thiostrepton and the inactivation of ppGpp, actinorhodin and undecylprodigiosin production. Western blotting showed that ribosomes from the RelC mutant KO-100 contain only one-eighth the amount of L11 protein found in ribosomes of the parent strain. The impairment of antibiotic production in KO-100 could be rescued by the introduction of mutations that confer resistance to streptomycin (str), which result in alteration of Lys-88 in ribosomal protein S12 to Glu or Arg. No accompanying restoration of ppGpp synthesis was detected in these RelC str double mutants.

Alleles↗
PubMed1997

Molecular analysis of the ribosomal L11 protein gene (rplK = relC) of Streptomyces griseus and identification of a deletion allele.

The rplK (= relC) gene, which codes for ribosomal protein L11, was cloned from Streptomyces griseus IFO13189 using a screening procedure based on polymerase chain reaction amplification of a gene segment that subsequently allowed the isolation of the complete gene from a gene library. rplK lies between the nusG gene, encoding a protein involved in antitermination of transcription, and the rplA gene, which encodes the ribosomal protein L1. Comparison of the rplK gene sequences of the wild-type strain and the presumed relC mutant strain 3-3 (originally isolated as a thiopeptin-resistant isolate) revealed a 12-bp deletion within the rplK gene from the mutant, flanked by a 4-bp repeat sequence in the corresponding region in the wild type. When the wild-type rplK gene was propagated on a low-copy-number vector in the relC mutant 3-3, the ability to produce guanosine 5'-diphosphate 3'-diphosphate, streptomycin, and submerged spores was completely restored to parental levels. The impaired ability to form aerial mycelium was, however, unaffected. Western blotting analysis showed that the ribosomes from the relC mutant 3-3 incorporate the mutant L11 protein normally, although the level of incorporation is approximately one-third that of the wild-type L11 protein in ribosomes of the parent strain. Propagation of the mutant rplK gene in the wild-type strain resulted in marked defects in growth, streptomycin production, and aerial mycelium formation, indicating that the mutant L11 protein exerts certain negative effects in the cells.

Alleles↗
PubMed1997

Expression of TrkB-like immunoreactivity in non-neural cells of rat periodontal ligament.

The Trk family, a group of high-affinity neurotrophin receptors, is divided into three subtypes, TrkA, TrkB and TrkC. These were originally found in neural elements, and are involved in neural development, maintenance and survival. Recent studies have shown that non-neural cells in vitro also express mRNA encoding some neurotrophin receptors. In our preliminary study, TrkB-like immunoreactivity (LI) was found in the various non-neural cells in the rat periodontal ligament. The present study was undertaken to clarify which cell types express Trk-LI, in particular two types of TrkB-LI, in the periodontal ligament of mature rats, using an immunocytochemical technique with polyclonal antibodies. Intense full-length TrkB-LI was clearly recognized in non-neural cells such as fibroblasts, osteoclasts, odontoclasts and cementoblasts as well as in neural elements. Relatively large cells with many cytoplasmic processes were also frequently immunopositive for full-length TrkB. Immunocytochemistry for TrkB[TK-], a truncated type, also demonstrated a similar immunostaining pattern to that of full-length TrkB in non-neural periodontal cells, and intense positive reactions in endothelial cells. Some non-neural cells were positive for TrkA and TrkC. These findings suggest that neurotrophic factors, the ligands of the Trk family, have certain effects on the proliferation and/or differentiation of non-neural cells, as well as on their neurotrophic functions.

Animals↗
PubMed1997

Effects of quinine on neural activity in cat primary auditory cortex.

The effect of systemically applied quinine on single-unit firing activity in primary auditory cortex was investigated in seven cats. A dose of 100 or 200 mg/kg of quinine hydrochloride was administered intramuscularly and recordings from the same units were performed prior to application and continuously up to on average 5.5 h after administration. All animals showed 10-40 dB of threshold shift about 30 min after administration and some animals showed recovery during the course of the investigation. Significant increases were found in spontaneous firing rates for low-firing-rate units (initial firing rate < 1 spike/s). For high-firing-rate units (initial firing rate > 1 spike/s) no significant changes were observed. There were no significant changes in modal and mean interspike interval. The time-to-rebound peak in the autocorrelation function for spontaneous firings was not altered significantly. The rate of burst occurrence showed no significant change. The best modulation frequency in response to stimulation with periodic click trains decreased after administration, but the limiting rate did not change. Peak cross-correlation coefficients for the spontaneous firings of simultaneously recorded cells showed a significant increase and the correlogram's central peak was significantly narrower after quinine application. Dose effects were only present for cross-correlation results and temporal modulation transfer functions. The results for both spontaneous firing rate, peak width in the cross-correlogram and click stimulation were similar to those observed in salicylate-treated cats (Ochi and Eggermont, 1996). The other findings were different from those observed after salicylate. It is obvious that the effects of quinine on the auditory system are not the same as those of salicylate. The increased synchronization of the spontaneous firings across different neurons observed after application of both drugs may be related to tinnitus.

Acoustic Stimulation↗
PubMed1997

Intraductal secretin test is as useful as duodenal secretin test in assessing exocrine pancreatic function.

We assessed the clinical usefulness of the intraductal secretin test in order to ascertain whether it can substitute for the conventional duodenal secretin test. Duodenal juice was obtained with a triple-lumen tube and pure pancreatic juice was obtained by retrograde cannulation of the main pancreatic duct using a duodenofiberscope. Pancreatic secretion was stimulated by a bolus intravenous injection of secretin (100 units). The two tests showed comparable interindividual coefficients of variation, significantly good correlations, and comparable diagnostic efficiencies. The intraductal secretin test showed no less reproducibility than that of the duodenal secretin test as reported in the literature. In the intraductal secretin test, secretory volume, peak flow rate, bicarbonate output, and lipase output yielded the best diagnostic efficiency, followed by amylase output and maximal bicarbonate concentration. In the intraductal secretin test, a 10-min collection provided as much information as a 20-min collection. We conclude, therefore, that the 10-min intraductal secretin test is as useful as the conventional duodenal secretin test in assessing exocrine pancreatic function and that the most discriminatory parameters are secretory volume, bicarbonate output, and amylase (or lipase) output.

Adult↗
PubMed1997

Does recurrent acute pancreatitis lead to chronic pancreatitis? Sequential morphological and biochemical studies.

The pathogenesis of chronic pancreatitis (CP) has been debated as to whether it is a de novo process or the consequence of acute pancreatitis (AP). We investigated whether recurrent AP in rats leads to CP, by sequential morphological and biochemical studies. Thirty male Wistar rats were fed a choline-deficient diet with intraperitoneal ethionine injections twice daily at a dose of 60 mg/100 g body weight twice weekly, and six rats were killed at 4, 6, and 8 weeks; the remaining 12 rats, followed without further treatment, were killed at 12 and 16 weeks. The pancreata from study and control groups were examined by histology, immunohistochemistry, and bio- and immunoassays. Histologically, moderate to severe intra- and perilobular fibrosis and other CP-like lesions appeared maximally at 8 weeks. Immunohistochemically, the earliest extracellular matrix change was strong fibronectin staining at 4 weeks, with a progressive increase to 8 weeks. Collagens I and III came to show strong, and collagen IV moderate, interstitial staining at 6-8 weeks. These morphological changes, however, returned to nearly normal at 16 weeks. Prolyl hydroxylase was significantly elevated at 4 and 6 weeks and normalized after 8 weeks, with no significant change in collagenase. In conclusion, our results suggest that even severe CP-like lesions induced by recurrent AP are reversible in the absence of persistently elevated prolyl hydroxylase and/or suppressed collagenase. The mechanism regulating these changes remains to be studied further.

Acute Disease↗
PubMed1997

Novel detoxification of the trichothecene mycotoxin deoxynivalenol by a soil bacterium isolated by enrichment culture.

A mixed microbial culture capable of metabolizing deoxynivalenol was obtained from soil samples by an enrichment culture procedure. A bacterium (strain E3-39) isolated from the enrichment culture completely removed exogenously supplied deoxynivalenol from culture medium after incubation for 1 day. On the basis of morphological, physiological, and phylogenetic studies, strain E3-39 was classified as a bacterium belonging to the Agrobacterium-Rhizobium group. Thin-layer chromatographic analysis indicated the presence of one major and two minor metabolites of deoxynivalenol in ethyl acetate extracts of the E3-39 culture filtrates. The main metabolite was identified as 3-keto-4-deoxynivalenol by mass spectroscopy and 1H and 13C nuclear magnetic resonance analysis. The immunosuppressive toxicity of 3-keto-4-deoxynivalenol was evaluated by means of a bioassay based on the mitogen-induced and mitogen-free proliferations of mouse spleen lymphocytes. This compound exhibited a remarkably decreased (to less than one tenth) immunosuppressive toxicity relative to deoxynivalenol, indicating that the 3-OH group in deoxynivalenol is likely to be involved in exerting its immunosuppressive toxicity. Strain E3-39 was also capable of transforming 3-acetyldeoxynivalenol but not nivalenol and fusarenon-X.

Animals↗