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H Ohtake

Publications and source records attributed to H Ohtake.

At least 127 records · Page 7Linked to original sources
PubMed1993

Cloning, sequence and characterization of the polyphosphate kinase-encoding gene (ppk) of Klebsiella aerogenes.

Polyphosphate kinase (PPK) catalyzes the formation of polyphosphate (polyP). The PPK-encoding gene (ppk) has been cloned from Klebsiella aerogenes ATCC9621. The gene possessed an open reading frame of 2055 bp capable of encoding a putative polypeptide with a deduced M(r) of 80,157. This polypeptide showed 93% similarity to the Escherichia coli PPK. The nucleotide sequence of the promoter region of K. aerogenes ppk differed from that of the previously sequenced E. coli ppk. A putative pho box sequence was found in the promoter region of K. aerogenes ppk. The expression of lacZ from the ppk promoter was increased in E. coli MV1184 under conditions of phosphate (Pi) limitation, but not in E. coli ANCS3 (phoB-), indicating that the ppk promoter is regulated by the phoB product. Increased levels of specific PPK activity were shown by expressing the cloned ppk at high levels, resulting in increased accumulation of polyP in E. coli.

Amino Acid Sequence↗
PubMed1993

Circadian rhythms of vasopressin release in primary cultures of rat suprachiasmatic nucleus.

We have developed a suprachiasmatic nucleus (SCN) cell culture system to study the cellular and molecular bases of the mammalian circadian pacemaker. The SCN regions were dissected from 4- to 6-day-old rat pups and dissociated cells were cultured in a defined medium. In all the cultures, the release of vasopressin showed clear circadian oscillation, which appeared within a few days in culture and lasted for more than a month. The peak of vasopressin release was observed at subjective day. These findings suggest that this culture system provides a valuable model for elucidating the mechanism of the circadian pacemakers.

Animals↗
PubMed1993

Chemotaxis away from thiocyanic and isothiocyanic esters in Pseudomonas aeruginosa.

Negative chemotaxis, the movement of organisms away from chemicals, was investigated in Pseudomonas aeruginosa using a rapid videotape method. Digital image processing was used to detect changes in bacterial numbers near the mouth of a capillary containing a test chemical. P. aeruginosa was found to be repelled by thiocyanic and isothiocyanic esters including allyl isothiocyanate, ethyl thiocyanate, methyl isothiocyanate and methyl thiocyanate. Particularly, the movement of bacteria away from methyl thiocyanate was so drastic that bacterial numbers near the mouth of the capillary decreased by approximately 80% within 30 s after the start of observation. Mutant strains, fully motile but lacking positive chemotaxis, did not escape away from the esters, suggesting a common mechanism between positive and negative chemotaxes in this organism.

Chemotaxis↗
PubMed1993

Heterogeneous expression of ornithine decarboxylase gene in the proximal tubule of the mouse kidney following testosterone treatment.

The expression of the ornithine decarboxylase (ODC) gene in the mouse kidney following testosterone treatment was examined using in situ hybridization histochemistry. Testosterone (n = 5) or vehicle (n = 5) was subcutaneously injected (1 mg/animal) into male BALB/c mice (8 weeks in age) 14 h before sacrifice. Animals were sacrificed under ether anesthesia, their kidneys were removed and immediately frozen in liquid nitrogen. Frozen sections (10-microns-thick) were cut on a cryostat. Sections were hybridized with 35S-labeled sense or antisense RNA probe. The hybridization continued for 24 h at 50 degrees C and emulsion autoradiography was subsequently performed. A marked increase in ODC mRNA was exclusively detected in the proximal tubule of the renal cortex in the testosterone-treated animals. The hybridization signal was greater in the outer portion of the proximal tubule than in the inner portion. No significant hybridization signal was detected either in the distal tubule, renal corpuscle or peritubular tissues. These results indicate that testosterone induces the expression of the ODC gene in the proximal tubule of the renal cortex, leading to the increase in ODC activity in the same region.

Animals↗
PubMed1993

Genetic improvement of Escherichia coli for enhanced biological removal of phosphate from wastewater.

The ability of Escherichia coli MV1184 to accumulate inorganic phosphate (Pi) was enhanced by manipulating the genes involved in the transport and metabolism of Pi. The high-level Pi accumulation was achieved by modifying the genetic regulation and increasing the dosage of the E. coli genes encoding polyphosphate kinase (ppk), acetate kinase (ackA), and the phosphate-inducible transport system (pstS, pstC, pstA, and pstB). Acetate kinase was employed as an ATP regeneration system for polyphosphate synthesis. Recombinant strains, which contained either pBC29 (carrying ppk) or pEP02.2 (pst operon), removed approximately two- and threefold, respectively, more Pi from minimal medium than did the control strain. The highest rates of Pii removal were obtained by strain MV1184 containing pEP03 (ppk and ackA). However, unlike the control strain, MV1184 (pEP03) released Pi to the medium after growth had stopped. Drastic changes in growth and Pi uptake were observed when pBC29 (ppk) and pEP02.2 (pst operon) were introduced simultaneously into MV1184. Even though growth of this recombinant was severely limited in minimal medium, the recombinant could remove approximately threefold more Pi than the control strain. Consequently, the phosphorus content of this recombinant reached a maximum of approximately 16% on a dry weight basis (49% as phosphate).

Biological Transport, Active↗
PubMed1993

Assessment of myometrial invasion by endometrial carcinoma: transvaginal sonography vs contrast-enhanced MR imaging.

OBJECTIVE: A prospective study was designed to compare transvaginal sonography with contrast-enhanced MR imaging to determine preoperatively the depth of myometrial invasion in patients with early-stage endometrial carcinoma. SUBJECTS AND METHODS: In 40 patients, findings on transvaginal sonograms, unenhanced T2-weighted MR images, and contrast-enhanced T1-weighted Mr images were compared with histologic findings. The depth of myometrial invasion was classified as stage E (tumor limited to endometrium, n = 12), stage S (superficial invasion: tumor invades up to 50% of the myometrium, n = 15), or stage D (deep invasion: tumor invades more than 50% of the myometrium, n = 13). RESULTS: Findings on transvaginal sonograms were accurate in 27 of 40 patients (accuracy, 68%); the depth of invasion was overestimated in five patients and underestimated in eight patients. The results of unenhanced T2-weighted MR images were accurate in 27 patients (accuracy, 68%), with four overestimations and nine underestimations. The results of contrast-enhanced T1-weighted MR images were accurate in 34 patients (accuracy, 85%), with five underestimations and one overestimation. In the assessment of each stage of myometrial invasion, the sensitivity and specificity of contrast-enhanced T1-weighted imaging were higher than those of T2-weighted MR imaging and transvaginal sonography. The false-positive diagnoses based on transvaginal sonograms and T2-weighted images, respectively, involved polypoid tumors (n = 4 and 2), distension of the endometrial cavity by pyometra (n = 2 and 1), the presence of myoma (n = 2 and 1), atrophy of the myometrium (n = 1 and 0), and poor tumor/myometrium contrast (n = 0 and 2). On contrast-enhanced MR images, accuracy was influenced only in a case of polypoid tumor, because tumor, endometrial cavity, and myometrium were clearly distinguished and residual myometrium was clearly visualized. With all imaging techniques, false-negative diagnoses were caused mainly by tumors with superficially spreading growth or microscopic invasion. With transvaginal sonography, infiltrative tumor also tended to be understaged (n = 3). CONCLUSION: Contrast-enhanced MR imaging is significantly superior to transvaginal sonography and unenhanced T2-weighted MR imaging for detecting myometrial invasion.

Adult↗
PubMed1993

Open heart surgery under total extracorporeal circulation in a patient with advanced glaucoma.

A patient with Wolff-Parkinson-White syndrome and severe glaucoma underwent division of the accessory pathway under total extracorporeal circulation (ECC). During ECC, systolic systemic pressure was maintained at 60-80 mmHg. Arterial pressure in the optic nerve terminal is reported to be half to one-third of systemic arterial pressure and approximates 20 mmHg during ECC. In the case presented, intraocular pressure was maintained below 15 mmHg throughout ECC. Postoperative examination of the patient revealed no change in visual acuity. During ECC, intraocular pressure may exceed the ocular bottom pressure, placing the optic nerve at risk of ischaemia. In cases where optic nerve ischaemia from ECC is likely, preoperative examination by an ophthalmologist is needed.

Adult↗
PubMed1992

Rapid method for analyzing bacterial behavioral responses to chemical stimuli.

A rapid method was developed to analyze bacterial behavioral responses to chemical stimuli. Digital image processing was used to detect the accumulation of bacteria at the mouth of a capillary containing an attractant. The accumulation of bacteria was determined from the total number of cells near the mouth of the capillary per videotape frame. This method was applied to measure the chemotactic response of Pseudomonas aeruginosa cells to serine, with results similar to those obtained by the classical capillary plating assay. The videotape method is much less time-consuming and makes it possible to assess the bacterial response to an attractant within a few minutes.

Journal Article↗
PubMed1992

Phosphate taxis in Pseudomonas aeruginosa.

Pseudomonas aeruginosa was shown to be attracted to phosphate. The chemotactic response was induced by phosphate starvation. The specificity of chemoreceptors for phosphate was high so that no other tested phosphorus compounds elicited a chemotactic response as strong as that elicited by phosphate. Competition experiments showed that the chemoreceptors for phosphate appeared to be different from those for the common amino acids. Mutants constitutive for alkaline phosphatase showed the chemotactic response to phosphate regardless of whether the cells were starved for phosphate.

Alkaline Phosphatase↗
PubMed1992

[Right coronary spasm immediately after coronary artery bypass grafting for the left coronary artery].

Right coronary spasm immediately after coronary artery bypass grafting for the left coronary artery in a 39-year-old male is described. After the patient was returned to ICU, ECG at leads II, III, and aVF changed suddenly, ventricular tachycardia (right ventricle origin) and cardiac arrest ensured. As neither administration of drug nor application of D.C. was effective. The chest was reopened at ICU. Though there was sufficient flow in the left coronary artery bypass graft flow, the right ventricle did not constrict at all. Right coronary artery spasm was diagnosed, and, upon application of the direct cardiac massage and D.C. at the cardiac surface, cardiac rhythm and blood pressure were normalized. IABP was inserted to improve cardiac function, and the chest was closed. In addition, nitroglycerin and diltiazem were infused continuously. No spasm has occurred after this episode, and the patient has been discharged and is doing well.

Adult↗
PubMed1992

[A new balloon electrode for intraoperative endocardial mapping].

To enhance the utility of epicardial mapping in the intraoperative determination of the location of the arrhythmic source, we developed a new balloon electrode covered with Presnet-tubular dressing material including 46 snap electrode recording sites. The bipolar recording sites, 1.0 mm in diameter and spaced at intervals of 1.5 mm, are constructed of gold and directly attached steel wire. This new balloon electrode was effective intraoperative determination of the lesion in 2 patients one with Wolff-Parkinson-White syndrome and the other with ventricular tachycardia.

Arrhythmias, Cardiac↗
PubMed1992

[Basic study of myocardial coagulation by intraoperative laser ablation: in the presence and absence of blood].

To investigate whether the efficacy of laser ablation therapy is affected by the color of the target organ, we irradiated 9 canine hearts through the epicardium with Nd-YAG laser (200 J, 400 J), and compared coagulated myocardial volume in the beating heart (reddish) with that in the stopped heart (whitish) infused with 0 degrees C saline (cardioplegic model) via a coronary artery. The coagulated myocardial volume of the beating heart was significantly larger than that of the arrested heart, indicating the YAG laser energy is absorbed by red myocardium to greater extent than it is by white myocardium. In conclusion, during intraoperative laser ablation, the presence or absence of blood in cardiac tissue is an important factor for safe irradiation.

Animals↗
PubMed1991

[A case of acute monocytic leukemia cutis treated with total skin electron beam irradiation].

A 35-year-old man with acute monocytic leukemia (AMoL) cutis was treated with total skin electron beam irradiation (TSEBI), because the widespread skin infiltration of AMoL appeared after induction chemotherapy. A skin nodule was authenticated as leukemic cell by biopsy. The patient was irradiated 4 times a week with 200 cGy per fraction to a total dose of 1200 cGy, using 6 MeV electrons from 8 directions. The therapy was accomplished separately on the upper and lower halves of the body. Focus-skin distance was 310 cm. An acrylic plate applicator 1 cm in thickness was used. The dimensions were 90 x 90 cm inside length and 90 cm in height. After completion of radiotherapy, the nodular lesions of the skin nearly disappeared. Although the patient survived only 3.5 months after beginning of radiotherapy due to systemic relapse, recurrence of the skin nodule was not seen. In this case TSEBI was therefore a useful treatment for skin infiltration of AMoL.

Adult↗
PubMed1991

Membrane-bound respiratory system of Enterobacter cloacae strain HO1 grown anaerobically with chromate.

Chromate has been demonstrated to be an electron acceptor in the respiratory chain of anaerobically grown Enterobacter cloacae strain HO1. By using potentiometric titration and low temperature spectroscopy, the spectral absorption of the anaerobic membrane vesicles of this organism in the presence of chromate was resolved into six peaks at 548, 549, 550, 555, 556, and 558 nm in the alpha band of the reduced minus oxidized spectra. The spectra elicited by chromate are attributed to cytochromes c548, c549, c550, b555, b556, and b558. Among these cytochromes, c548 was found to be specifically involved in electron transfer to chromate.

Anaerobiosis↗