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Biomedical subjects

K Ochi

Publications and source records attributed to K Ochi.

At least 145 records · Page 8Linked to original sources
PubMed1988

Free fatty acids in human pure pancreatic juice.

Human pure pancreatic juice (PPJ) and serum were analyzed for free fatty acids (FFAs) to study whether the damage to pancreatic cell membranes in pancreatitis is reflected as abnormal FFAs concentration and composition. Patients consisted of 13 normal controls, 7 patients with acute pancreatitis (AP) in remission, and 27 with chronic pancreatitis (CP). PPJ was collected at 2-min intervals after secretin and then cholecystokininpancreozymin stimulation by endoscopic cannulation of the pancreas. The following results were obtained: (a) serum FFAs concentration and composition showed no significant difference between the three groups. (b) FFAs concentration in PPJ was significantly raised in CP through all secretory phases. The rise was significant only in "secretin phase" in AP. In many of the cases with raised FFAs concentration in PPJ, the FFAs composition was similar to that in serum. (c) Arachidonic acid, undetected in normal PPJ, was disproportionately high in concentration and composition in PPJ of eight patients with CP. Two mechanisms were proposed to explain these abnormalities: transudation of serum FFAs into the pancreatic duct and local production of arachidonic acid as a result of the damage to pancreatic cell membranes.

Acute Disease↗
PubMed1988

Genetic mapping and physiological consequences of metE mutations of Bacillus subtilis.

Three metE mutations of Bacillus subtilis, which cause cells to have a 25- to 200-fold decrease in L-methionine S-adenosyltransferase (EC 2.5.1.6) activity, were mapped between bioB and thr. The corresponding three metE mutants contained three- to fourfold less intracellular S-adenosylmethionine (SAM) but at least sevenfold more methionine than the metE+ strain when grown in synthetic medium. This indicates a strong feedback control of SAM on its synthesis. However, only the metE2 strain, with the lowest SAM concentration, grew at a slightly lower rate than the parent, which showed that an intracellular concentration of about 25 microM SAM was critical for growth at the normal rate. Neither DNA methylation (measured by bacteriophage luminal diameter 105 restriction) nor sporulation was affected at this low SAM concentration. Addition of methionine to the growth medium caused an increase in the pool of SAM in some but not all metE mutants. Coaddition of adenine did not change this result. However, the extent of sporulation (induced by mycophenolic acid) was decreased 50-fold in all mutants by the addition of methionine and adenine. Therefore, the combination of methionine and adenine suppresses sporulation regardless of whether it causes an increase in the level of SAM.

Adenine↗
PubMed1988

Physiological analysis of bicozamycin high-producing Streptomyces griseoflavus used at industrial level.

Streptomyces griseoflavus, a bicozamycin-producing wild type strain and its high-producing one derived from it by multiple (greater than 15) mutagenic treatments, were analyzed physiologically and biochemically. The high-producing strain was characterized by: (1) An increased pool size of amino acids including leucine and isoleucine, precursors for bicozamycin synthesis, (2) an earlier and greater accumulation of intracellular ppGpp, (3) a more accentuated decrease in GTP pool size, (4) a higher specific activity of ornithine transcarbamylase which produces citrulline, (5) an increased ability to form aerial mycelium, and (6) an increased resistance to its own antibiotic. We propose that (1), (2) and (4) may be responsible for the high yields of bicozamycin and, possibly, of some other antibiotics produced by Streptomyces sp.

Amino Acids↗
PubMed1988

[Changes in the levels of lipid peroxides in regenerating rat liver and the effect of pretreatment with CoQ10].

The present study was undertaken to determine whether CoQ10 pretreatment could modify cellular free radical metabolism in regenerating rat liver and enhance hepatic DNA synthesis. Male Wistar rats (250-300 g) were used. Partial 70% hepatectomy was performed according to Higgins and Anderson. CoQ10 (6 mg/kg body weight) and its solvent as a placebo were injected intravenously 1 hour before operation. Twenty-four hours or 48 hours after 70% hepatectomy resulted in 55% or 50% decreases of hepatic ATP, and marked decreases of endogenous CoQ homologs (CoQ9 and CoQ10), alpha-tocopherol and reduced glutathione (GSH) in remnant liver and was accompanied by 2.5-fold increases in lipid peroxides. However, in CoQ10-treated animals synthesis of ATP was accelerated after 48 hours after partial hepatectomy. There were no changes in the levels of CoQ9, alpha-tocopherol, or GSH or in the level of the enhanced CoQ10 in regenerating liver. The pretreatment also completely suppressed the elevation of lipid peroxide. Moreover, CoQ10 administration markedly increased hepatic DNA synthesis at 48 hours after partial hepatectomy. These results indicate that cellular damage during hepatic regeneration is in part due to lipid peroxidation, and suggest that CoQ10 is effective in the pretreatment of liver resection.

Animals↗
PubMed1987

Leiomyosarcoma of inferior vena cava.

A case of leiomyosarcoma of the inferior vena cava is presented and pertinent clinical features of 57 reported cases in the English literature are reviewed.

Female↗
PubMed1987

Clinical course and prognosis of chronic pancreatitis.

Course and prognosis of 125 patients with chronic pancreatitis (CP) were evaluated. Follow-up period ranged from 1-20 years with a median of 6.3 years. The following conclusions were obtained. Recent increase of CP in our clinics was ascribed to alcoholic CP and idiopathic CP in the aged. Of 106 patients with pain, 74 showed improvement or disappearance of pain. Drinking habit and observation period were the main factors determining the rate of pain relief. Serial endoscopic retrograde pancreatography (ERP) showed aggravation in 17/47 patients, cholecystokinin-pancreozymin (CCK-PZ) secretin test in 4/40 patients, and oral glucose tolerance test (OGTT) in 7/25 patients. Exocrine function showed improvement in five patients, whereas endocrine function showed none. Improvement or aggravation of exocrine function was closely related to drinking habit. Main complications included 15 cases of peptic ulcer, 19 of pancreatic pseudocyst, and 15 of bile duct stenosis. Twenty-six patients died, often due to malignant neoplasms and diabetic complications. Those who continued drinking as much showed a lower survival rate than those who discontinued or decreased alcohol intake. The socioeconomic status deteriorated often due to pain or alcoholism. Three patients had to degrade jobs and six fell into inactive social life.

Age Factors↗
PubMed1987

Metabolic initiation of differentiation and secondary metabolism by Streptomyces griseus: significance of the stringent response (ppGpp) and GTP content in relation to A factor.

I investigated the significance of the intracellular accumulation of guanosine 5'-diphosphate 3'-diphosphate (ppGpp) and of the coordinated decrease in the GTP pool for initiating morphological and physiological differentiation of Streptomyces griseus, a streptomycin-producing strain. In solid cultures, aerial mycelium formation was severely suppressed by the presence of excess nutrients. However, decoyinine, a specific inhibitor of GMP synthetase, enabled the cells to develop aerial mycelia in the suppressed cultures at concentrations which only partially inhibited growth. A factor (2S-isocapryloyl-3S-hydroxymethyl-gamma-butyrolactone) added exogenously had no such effect. Decoyinine was also effective in initiating the formation of submerged spores in liquid culture. The ability to produce streptomycin did not increase but decreased drastically on the addition of decoyinine. This sharp decrease in streptomycin production was accompanied by a decrease in intracellular accumulation of ppGpp. A relaxed (rel) mutant was found among 25 thiopeptin-resistant isolates which developed spontaneously. The rel mutant had a severely reduced ability to accumulate ppGpp during a nutritional shift-down and also during postexponential growth and showed a less extensive decrease in the GTP pool than that in the rel+ parental strain. The rel mutant failed to induce the enzymes amidinotransferase and streptomycin kinase, which are essential for the biosynthesis of streptomycin. The abilities to form aerial mycelia and submerged spores were still retained, but the amounts were less, and for both the onset of development was markedly delayed. The decreased ability to produced submerged spores was largely restored by the addition of decoyinine. This was accompanied by an extensive GTP pool decrease. The rel mutant produced A factor normally, indicating that synthesis of A factor is controlled neither by ppGpp nor by GTP. Conversely, a mutant defective in A-factor synthesis accumulated as much ppGpp as did the parental strain. It was concluded that morphological differentiation of S. griseus results from a decrease in the pool of GTP, whereas physiological differentiation results from a more direct function of the rel gene product (ppGpp). It is also suggested that A factor may render the cell sensitive to receive and respond to the specified signal molecules, presumably ppGpp (for physiological differentiation) or GTP (for morphological differentiation).

4-Butyrolactone↗
PubMed1987

Arsenazo III Ca2+-transients of Xenopus skeletal muscle during repetitive stimulation in hypertonic solution.

The arsenazo III Ca2+-transients (AZ signals) were measured in hypertonic solution. The muscle fiber of Xenopus was stimulated at the frequency of 0.1/s. The AZ signal responding to the first stimulus in hypertonic Ringer solution was nearly similar to that in normal Ringer solution. After 8 repetitive stimuli, however, time to peak was increased to 3 times and decay time constant was up to 4 times as long as the control. The apparent inhibition of Ca2+ uptake into sarcoplasmic reticulum was supposed to be the origin of the prolongation in time to peak and decay time course.

Action Potentials↗
PubMed1986

Crystal-matrix interrelations in brushite and uric acid calculi.

Brushite and uric acid calculi were studied by means of scanning electron microscopy with the partial dissolution method and transmission electron microscopy. Brushite calculi consist of radially oriented columnar crystals which have sheet-like substructure. The organic matrix is identified chiefly at the outside of the crystals but partly included between the substructure. The concentric matrix bands are often dislocated between the neighbouring crystals. Uric acid calculi also consist of radially oriented columnar crystals, and a fine meshwork of the organic matrix is incorporated within the crystals. The concentric matrix layers of different density are angled according to the crystal lattice. These findings indicate that the organic matrix arose from a mucinous surface coat, at least in the radially striated calculi. The crystals continued to grow in this gel-state milieu, either thrusting the matrix aside or incorporating it within the crystals.

Calcium Oxalate↗
PubMed1986

A decrease in GTP content is associated with aerial mycelium formation in Streptomyces MA406-A-1.

Aerial mycelium formation by Streptomyces sp. MA406-A-1, a formycin-producing strain, was suppressed by the presence of excess nutrient. In such suppressed cultures, decoyinine, which specifically inhibits GMP synthetase, initiated the formation of aerial mycelium at concentrations which only partially inhibited growth. The intracellular GTP pool of organisms growing in liquid culture markedly decreased on the addition of decoyinine. Decoyinine was also effective in initiating aerial mycelium formation of three other Streptomyces spp. examined. Regardless of the successful initiation of aerial mycelium formation, the ability of the cells to produce antibiotics (formycin or actinomycin D) did not increase, but decreased, on the addition of decoyinine. It is concluded that aerial mycelium formation by Streptomyces results from a decrease in the pool of GTP (or GDP), whereas antibiotic synthesis results from a different signal(s).

Adenosine↗
PubMed1986

Occurrence of the stringent response in Streptomyces sp. and its significance for the initiation of morphological and physiological differentiation.

Streptomyces sp. MA406-A-1 produced formycin (a nucleoside antibiotic) in parallel with cell growth in a synthetic medium. When the synthetic medium was supplemented with 1% (w/v) Casamino acids, however, formycin was produced only after the end of exponential growth. The intracellular ppGpp pool increased gradually towards the end of exponential growth and was maximal at the beginning of formycin production. After shift down from Casamino acids medium to synthetic medium, the ppGpp pool increased immediately, while the GTP pool decreased; under such conditions, the ability to produce formycin increased eightfold. Relaxed (rel) mutants, the first isolated for a Streptomyces species, were found at high incidence (10%) among spontaneous thiopeptin-resistant isolates and had severely reduced abilities to accumulate ppGpp. These rel mutants also failed to produce formycin under the usual culture conditions and exhibited numerous pleiotropic effects such as an inability to produce melanin and an extended delay of aerial mycelium formation. Thus Streptomyces sp. exhibited a typical stringent response, and the response initiated (or was needed for) the induction of secondary metabolism. The response may have also participated in the initiation of aerial mycelium formation by decreasing the intracellular GTP pool.

Amino Acids↗