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Biomedical subjects

H Ohtake

Publications and source records attributed to H Ohtake.

At least 145 records · Page 8Linked to original sources
PubMed1990

Chromate-resistance in a chromate-reducing strain of Enterobacter cloacae.

Resistance to toxic hexavalent chromium (chromate: CrO4(2)) in Enterobacter cloacae strain HO1, isolated from an activated sludge sample, was investigated under aerobic and anaerobic conditions. Decreased uptake of 51CrO4(2-) in E. cloacae strain HO1 was observed under aerobic conditions, when compared with a standard laboratory E. cloacae strain (IAM 1624). Under anaerobic conditions E. cloacae strain HO1 was able to reduce hexavalent chromium to the less toxic trivalent form. When E. clocacae strain HO1 was grown with nitrate anaerobically, the cells were observed to lose simultaneously their chromate-reducing ability and chromate-resistance under anaerobic conditions.

Anaerobiosis↗
PubMed1990

A method for removal of toxic chromium using dialysis-sac cultures of a chromate-reducing strain of Enterobacter cloacae.

A method for removal of toxic hexavalent chromium (chromate: CrO2-4) was developed by use of dialysis-sac cultures of a chromate-reducing strain of Enterobacter cloacae (HO1). E. cloacae strain HO1 cells were put in dialysis (semipermeable membrane) sacs, and the sacs were submerged in water containing toxic CrO2-4. The dialysis sacs allowed CrO2-4 to diffuse into the culture, and CrO2-4 was reduced anaerobically in the dialysis sacs by the E. cloacae cells. Because reduced chromium readily formed insoluble chromium hydroxides in the dialysis sacs, the greater part of reduced chromium was unable to diffuse out through the semipermeable membrane. Thus the dialysis culture of E. cloacae strain HO1 could successfully remove toxic chromium from the surrounding water. If the initial concentration of CrO2-4 was less than 4 mM (208 ppm as chromium), about 90% of the total chromium could be removed from water by the described method.

Bacteriological Techniques↗
PubMed1990

Biooxidation of a synthetic waste by a microbial film grown on the liquid surface in a shallow flow reactor.

A new process of biological waste treatment was developed by use of microbial films grown on the liquid surface in a shallow flow reactor. The performance of this process was tested using a synthetic waste that contained acetic acid as a model organic pollutant. About 90% of acetic acid (10,000 mg/L-1) in the synthetic waste was removed by setting alpha tau: (alpha specific liquid surface area, cm-1, and tau: hydraulic liquid detention time, h) higher than 15 cm-1/h. It was necessary to maintain alpha large enough (more than 10 cm-1 in most cases) to satisfy oxygen demand for the biooxidation. The oxygen balance and TOC determinations showed that the acetic acid removed was completely oxidized with oxygen transferred through the liquid surface. This process would contribute to energy savings, since it requires no forced aeration for oxygen supply.

Acetates↗
PubMed1990

Muscle fiber conduction velocity and contractile properties estimated from surface electrode arrays.

Using an array of surface electrodes set 5 mm apart, we estimated the conduction velocities of muscle fibers during submaximal voluntary isometric contraction of human first dorsal interosseous muscle. The conduction velocity obtained by the averaging method ranged from 3.2 to 5.0 m/sec with a mean of 4.2 m/sec. Twitch tensions in the muscle detected during voluntary isometric contractions ranged from 0.31 to 5.97 g with a mean of 2.75 g based on an averaging method triggered by surface myoelectric signals. Threshold forces of the motor units varied from 120 to 930 g. The rise time of the force developed by isometric adduction ranged from 36.0 to 75.4 msec, with a mean of 55.4 msec. The conduction velocity of the muscle fiber showed a high correlation with the twitch (r = 0.71, n = 50; P less than 0.001) and threshold (r = 0.52, n = 50; P less than 0.001) forces, but a low one with rise time (r = -0.32, n = 50; P less than 0.05). The use of the averaging method with surface electrode arrays, especially for voluntary isometric contractions, shows that motor unit conduction velocity and contractile properties are functionally correlated.

Adult↗
PubMed1990

Discordant Tl-201 and Tc-99m imaging in a patient with thyroid carcinoma and Hashimoto's disease.

In a case of Hashimoto's disease complicated by thyroid gland cancer, the primary site of the cancer was visualized as a cold nodule on Tc-99m pertechnetate scintigraphy, as a warm nodule on Tl-201 early imaging, and as a hot nodule on Tl-201 delayed imaging. Generally, Tl-201 shows markedly diffuse accumulation in the lesions of Hashimoto's disease. The warm nodules observed on early scans suggested similar accumulation at the sites of Hashimoto's disease and thyroid cancer. The hot nodules on delayed imaging may be due to the difference in Tl-201 washout time between the sites of Hashimoto's disease and thyroid cancer. There was markedly increased Tl-201 accumulation in bilateral cervical metastatic lymph nodes on both early and delayed images.

Carcinoma, Papillary↗
PubMed1990

Cloning, nucleotide sequence, and expression of the chromate resistance determinant of Pseudomonas aeruginosa plasmid pUM505.

The chromate resistance determinant of Pseudomonas aeruginosa plasmid pUM505 was cloned into broad-host-range vector pSUP104. The hybrid plasmid containing an 11.1-kilobase insert conferred chromate resistance and reduced uptake of chromate in P. aeruginosa PAO1. Resistance to chromate was not expressed in Escherichia coli. Contiguous 1.6- and 6.3-kilobase HindIII fragments from this plasmid hybridized to pUM505 but not to P. aeruginosa chromosomal DNA and only weakly to chromate resistance plasmids pLHB1 and pMG6. Further subcloning produced a plasmid with an insert of 2,145 base pairs, which was sequenced. Analysis of deletions revealed that a single open reading frame was sufficient to determine chromate resistance. This open reading frame encodes a highly hydrophobic polypeptide, ChrA, of 416 amino acid residues that appeared to be expressed in E. coli under control of the T7 promoter. No significant homology was found between ChrA and proteins in the amino acid sequence libraries, but 29% amino acid identity was found with the ChrA amino acid sequence for another chromate resistance determinant sequenced in this laboratory from an Alcaligenes eutrophus plasmid (A. Nies, D. Nies, and S. Silver, submitted for publication).

Amino Acid Sequence↗
PubMed1990

Membrane-associated chromate reductase activity from Enterobacter cloacae.

Washed cells of Enterobacter cloacae HO1 reduced hexavalent chromium (chromate: CrO4(2-) anaerobically. Chromate reductase activity was preferentially associated with the membrane fraction of the cells. Right-side-out membrane vesicles prepared from E. cloacae cells showed high chromate reductase activities when ascorbate-reduced phenazine methosulfate was added as an electron donor.

Cell Membrane↗
PubMed1990

Evaluation of the therapeutic effect of percutaneous nephroureterolithotomy by Tc-99m diethylenetiaminepentaacetic acid (DTPA) renal scintigraphy--alteration of the renal fraction of blood flow, split-GFR, and renal mean transit time.

To evaluate the therapeutic effects of percutaneous nephroureterolithotomy, the renal function of eleven patients with renal calculi was studied, pre- and post-intervention. Renal function was determined, by renal scintigraphy with the renal agent, Tc-99m diethylenetriaminepentaacetic acid (DTPA). In each renal scintigram the renogram curve was analyzed and the following were determined by deconvolution analysis; the renal fraction of blood flow (RFBF), DTPA-glomerular filtration ratio (GFR), and the renal mean transit time (MTT). The successful results in percutaneous nephroureterolithotomy (PNL) was proven using the radionuclide technique in most cases. From these results it can be concluded that renal scintigraphy is an effective procedure to evaluate the effect of PNL for treating renal calculi and secondary hydronephrosis.

Adult↗
PubMed1990

Increased gallium-67 citrate uptake in the breast of a patient with gynecomastia.

Although the accumulation of Ga-67 citrate in gynecomastia has been described, no researchers have reported that Ga-67 citrate accumulates in a "doughnut" pattern. Basically, gynecomastia is due to an increase of estrogens. Since estrogens accelerate the proliferation of lactiferous ducts in the center of breast, Ga-67 citrate may accumulate in it. On the hand, prolactin increases the proliferation of the glandular lobules and the acinus. When the serum prolactin increases after child birth or renal insufficiency, the image from the accumulation of Ga-67 citrate in the breast may have a "doughnut" pattern. A patient with gynecomastia had high levels estrogens because he was being treated with an estrogen medication. He was referred for liver cirrhosis. The results of the present report indicate that the "doughnut" pattern occurs in the margin of the hyperplasic glandular lobule.

Citrates↗
PubMed1990

Tc-99m RBC imaging for demonstrating intermittent intestinal bleeding.

A case of intestinal bleeding caused by multiple ulcerations near the terminal ileum is presented. Abdominal scanning with Tc-99m tagged red blood cells (Tc-99m RBC) demonstrated the intermittent bleeding in short intervals. Selective angiography did not demonstrate the bleeding site. Exploratory laparotomy showed 3 ulcers on the ileum at a site near the terminal ileum, with bleeding from one site. Tc-99m RBC abdominal scanning was very useful in this case for localization of the site of gastrointestinal bleeding before laparotomy.

Erythrocytes↗
PubMed1990

Abdominal scanning using autologous human red blood cells labeled with Tc-99m: detection of a horseshoe kidney.

A horseshoe kidney was incidentally diagnosed while performing an abdominal scan using autologous human red blood cells labeled with Tc-99m (Tc-99m RBC) on a patient with suspected gastrointestinal bleeding. This patient repeatedly tested positive on occult blood stool examinations. In the first scintigram, an increase in well-defined activity was found on the right side under the liver. This could have been caused either by bleeding of the gastric antrum or the duodenal bulb. A second abdominal scan with Tc-99m RBC revealed faint radionuclide accumulation in the shape of a horseshoe with symmetrical, well-defined activity. However, the well-defined activity decreased with time on both images, and on this basis a horseshoe kidney was diagnosed.

Abdomen↗
PubMed1990

Acute-phase kidney transplants show early peak appearance in Tc-99m DTPA renogram.

Kidney transplants have been evaluated using a radionuclide technique to determine perfusion index (PI), mean transit time (MTT), and the parameters in renogram curve (Tmax, T1/2, and T2/3). The values for Tmax, T1/2, and T2/3 were also determined in normal volunteers. The results indicated that the Tmax value was less than 2 minutes, one week after transplantation. The other data were within normal limits. The appearance of Tmax was very early. The early time activity curve (TAC) was quite similar to the blood disappearance curve, TAC did not have the functional-phase, so-called, 2nd-phase. These data suggested that there could be an abnormality of the renal circulation in the transplanted kidney. The suggestion offers the new finding in a field of renal transplantation using radionuclide technique.

Adult↗