Biomedical subjects

H Ohta

Publications and source records attributed to H Ohta.

At least 271 records · Page 15Linked to original sources

PubMed1998

[Superior sagittal sinus thrombosis presenting with subarachnoid hemorrhage in a patient with aplastic anemia].

A 54-year-old female, who had been treated for aplastic anemia by metenolone acetate since 1981, developed a sudden unconsciousness in September 1995. On admission, she was drowny, CT showed a subarachnoid hemorrhage (SAH) in the right Sylvian fissure. Angiography demonstrated a complete occlusion of the superior sagittal sinus. The SAH was assumed to be originated from rupture of the right Sylvian vein, which was irregularly dilated on angiography. The dural sinus thrombosis was thought to be caused by a long term use of metenolone acetate, and it was discontinued. But her platelet count dropped due to the aggravation of aplastic anemia, and she developed repeated hemorrhagic infarction. An active anticoagulant therapy for the dural sinus thrombosis was thought to be inappropriate because she had the aplastic anemia and the hemorrhagic infarction recurred. We have successfully treated this case by mild anticoagulant therapy with nafamostat mesilate (Futhan).

Anemia, Aplastic↗

PubMed1998

[Efficacy of granisetron as anti-emetic agent for emesis induced by intra-arterial injection therapy for hepatocellular carcinoma].

The effect of granisetron in preventing nausea and emesis induced by intraarterial chemotherapy was comparatively studied with a historical control group (46 cases) in 50 patients with hepatocellular carcinoma receiving intraarterial anti-tumor drugs such as cisplatin and doxorubicin. Emesis was perfectly controlled in 39 out of 50 patients in the treatment group (78%), in comparison to 33 out of 46 patients (71.7%) in the historical control group. This represented no statistical significance between the two groups. In terms of the severity of nausea, however, the granisetron group demonstrated significant superiority to the control group with 27 out of 50 patients (54%) being free of symptoms compared with 16 out of 46 patients (34.8%) in the control group. A stratified analysis of the data also demonstrated significant superiority of the granisetron group over the historical group in the number of emetic episodes and the severity of nausea in female patients, who are more predisposed to emesis. The above results confirm the usefulness of granisetron as an antiemetic agent used for the prevention of acute nausea and emesis induced by intraarterial chemotherapy.

Adult↗

PubMed1998

[99mTc(V)-DMSA accumulation in gynecomastia].

The accumulation of 99mTc(V)-DMSA in bilateral breasts was recognized in a 60-year-old male with drug-induced gynecomastia. There are some reports describing 99mTc(V)-DMSA accumulation in normal female breast, fibrous dysplasia of the breast and metastatic lesions of breast carcinoma, but to my knowledge, there have been no reports describing 99mTc(V)-DMSA accumulation in gynecomastia.

Digoxin↗

PubMed1997

Predictive value of genetic diagnosis for cancer micrometastasis: histologic and experimental appraisal.

BACKGROUND: The recently introduced genetic diagnosis of cancer micrometastasis is quite attractive because of its high detection sensitivity. Not infrequently, however, there are marked discrepancies between genetic and conventional histologic diagnoses, especially concerning lymph nodes from colon carcinoma patients. Because the histologic approach has long been relied on in the clinic, the reasons for the differences in results need to be elucidated. METHODS: Serial sections of genetic diagnosis positive but histologic negative lymph nodes of colon carcinoma patients were prepared for histologic and immunohistochemical studies. To investigate the possible contaminating influence of DNA sequences derived from degraded carcinoma cells from the primary site through the lymphatics, the authors also injected purified DNA of human colon carcinoma cells (SW480) into the foot pads of rats and sequentially examined lymph nodes using genetic diagnosis methodology. RESULTS: Careful histologic examination of genetic diagnosis positive, histologically negative lymph nodes of colon carcinoma patients confirmed the absence of cancer cells, whereas p53 protein was immunohistochemically demonstrated to be present in the cytoplasm of sinus histiocytes. In the rat experiment, positive reactions were obtained with the inguinal lymph nodes beginning 30 minutes after the injection, and lymph nodes at various sites were subsequently affected, even after a 72-hour period. CONCLUSIONS: The current study thus suggests that positive results with genetic diagnosis may simply indicate the presence of tumor DNA and do not necessarily mean that viable cancer cells are present. Although the genetic approach may still hold promise for the detection of cancer micrometastases, its predictive value should be carefully assessed clinicopathologically, because its supersensitivity may be associated with a greatly increased false-positive rate.

Animals↗

PubMed1997

A survey of Salmonella enteritidis in spent hens and its relation to farming style in Hokkaido, Japan.

In order to estimate the distribution of Salmonella including Salmonella enteritidis (SE) and SE-antibodies in commercial layer hen flocks in Hokkaido, the northern prefecture of Japan, a survey of spent layer hens was performed, from August 1996 to January 1997. From the three spent hen processing plants, samples of intestines and sera were collected from 740 birds presented for slaughter from 37 flocks of 22 layer hen farms. Intestines from each birds were cultured for Salmonella including Salmonella enteritidis. Serum from each bird was examined for SE-antibody with the enzyme-linked immunosorbent assay (ELISA). Salmonella (any serotype) and Salmonella enteritidis were isolated from 50 (6.8%) and three (0.4%) of 740 birds, respectively, and SE-antibody positive values were recorded from seven birds (0.9%). SE-antibody positive birds did not always indicate isolation of Salmonella enteritidis, however SE-antibody positive hens were demonstrated only from Salmonella enteritidis positive flocks. Salmonellae were isolated from the birds of ten layer hen farms, all of these hens were raised in houses without windows and with automatic feeders. No isolations of salmonella were made from birds raised in houses with windows. From the windowless houses, Salmonellae were isolated from 46 (21.8%) of 260 birds in houses with four to six cages piled up vertically, and from six (2.5%) of 240 samples from the houses with four to five cages piled in a slanting manner.

Animals↗

PubMed1997

Regulatory effects of aggregated LDL on apoptosis during foam cell formation of human peripheral blood monocytes.

In order to investigate the mechanisms how modified lipoproteins enhance foam cell formation, we cultured peripheral blood monocytes with various stimulants and examined the effects of aggregated low-density lipoprotein (agLDL) on cell viability and lipid metabolism. AgLDL could completely inhibit phorbol ester-induced apoptosis, which was accompanied by intracellular cholesterol accumulation. Suppression of apoptosis-promoting proteases, ICE and CPP32, was observed in agLDL-treated cells. This indicates that agLDL accelerates foam cell formation through inhibition of apoptosis and enhancement of lipid accumulation in activated monocytes. By contrast, apoptosis was enhanced when monocytes were cultured with agLDL and M-CSF. Intracellular cholesterol accumulation was not significant in M-CSF treated cells. This suggests that M-CSF may act anti-atherogenic through apoptotic elimination of lipid-baring macrophages and enhanced lipid turnover. Our observation supports the novel hypothesis that regulation of apoptosis may play an important role in the development of atherosclerosis.

Apoptosis↗

PubMed1997

Cytokine production regulating Th1 and Th2 cytokines in hemophagocytic lymphohistiocytosis.

Hemophagocytic lymphohistiocytosis (HLH) is caused by the hyperactivation of T cells and macrophages. The clinical characteristics associated with this disease result from overproduction of Th1 cytokines including interferon-gamma (IFN-gamma), interleukin-2 (IL-2), and tumor necrosis factor-alpha (TNF-alpha). In this study, we analyzed the production of IL-12 and IL-4, which determine Th1 and Th2 response, respectively, and IL-10, which antagonizes Th1 cytokines, in 11 patients with HLH. IL-12 was detected in plasma in all patients (mean peak value, 30.0 +/- 5.0 pg/mL), while IFN-gamma was massively produced in nine patients (mean peak value, 79.2 +/- 112.0 U/mL). IL-4 was not detected in any of the patients. Plasma IL-10 levels were elevated in all patients (mean peak value, 2,698.0 +/- 3,535.0 pg/mL). There was a positive correlation between the levels of IFN-gamma and IL-10 (P < .01). The plasma concentrations of these cytokines were initially high, before decreasing after the acute phase. However, the decrease in IL-10 levels was slower than that of IFN-gamma. Although the concentration of IL-12 was high at the acute phase, in some patients, a peak in the level was delayed until the chronic phase. Thus, in HLH, production of cytokines that promote development of Th1 cells appears to be predominant over that for Th2 cell development. Overproduction of IL-10 was also observed indicating that a mechanism suppressing hyperactivation of Th1 cells and monocytes/macrophages functions in patients with this disease.

Child↗

PubMed1997

Identification of domains on the 43 kDa chlorophyll-carrying protein (CP43) that are shielded from tryptic attack by binding of the extrinsic 33 kDa protein with photosystem II complex.

The structural association of the spinach 33 kDa extrinsic protein with the 43 kDa chlorophyll-carrying protein (CP43) in oxygen-evolving photosystem II (PS II) complexes was investigated by comparing the peptide mappings and N-terminal sequences of the trypsin-digested products of NaCl-washed PS II membranes, which bind the 33 kDa protein, with those of CaCl2-washed PS II membranes, which lack the 33 kDa protein. (1) Peptide from N-terminus to Arg26 of CP43, which is exposed to stromal side, was digested in both PS II membranes, independent of binding of the 33 kDa protein. (2) Peptide bond of Arg357-Phe358 located in the large extrinsic loop E of CP43, which is exposed to lumenal side, was cleaved by trypsin in CaCl2-washed PS II membranes but not in NaCl-washed PS II membranes. This indicates that the region around Arg357-Phe358 in loop E of CP43 is shielded from tryptic attack by binding of the 33 kDa protein to PS II. (3) Trypsin treatment of CaCl2-washed PS II membranes also cleaved peptide bond between Lys457 and Gly458 in C-terminal region of CP43, while no cleavage of this region was detected by trypsin treatment of NaCl-washed PS II membranes. This implies that a conformational change of the C-terminal region of CP43 which is exposed to stromal side occurred upon removal of the 33 kDa protein, which makes the C-terminal region accessible to trypsin. (4) Release of peptide from Gln60 to C-terminus of the alpha-subunit of cytochrome b-559 was detected only in trypsin treatment of CaCl2-washed PS II membranes, indicating that the C-terminal region of this subunit is shielded from tryptic attack by binding of the 33 kDa protein. (5) The PS II membranes, in which Arg357-Phe358, Lys457-Gly458 of CP43 and the C-terminal part of the cytochrome b-559 alpha-subunit had been cleaved by trypsin, was no longer able to bind the 33 kDa protein. This strongly suggests that a domain in loop E of CP43 and/or the C-terminal region of the cytochrome b-559 alpha-subunit are necessary for binding of the extrinsic 33 kDa protein to PS II.

Amino Acid Sequence↗

PubMed1997

Long-range interaction between the P2.1 and P9.1 peripheral domains of the Tetrahymena ribozyme.

The Tetrahymena ribozyme possesses peripheral domains, termed P9.1 and P9.2. They are nonessential in the mechanism of the catalytic reaction but contribute to enhance the catalytic activity of the ribozyme. It has been postulated that P9.1 is capable of forming Watson-Crick base pairings with another peripheral domain, P2.1. We report here the existence of long-range base pairings between the loop regions of these two domains and show that this interaction apparently plays a role in enhancing the catalytic activity of the ribozyme.

Animals↗

PubMed1997

Determination of Aconitum alkaloids in blood and urine samples. I. High-performance liquid chromatographic separation, solid-phase extraction and mass spectrometric confirmation.

Determination of four toxic Aconitum alkaloids, aconitine, mesaconitine, hypaconitine and jesaconitine, in blood and urine samples has been established using high-performance liquid chromatography (HPLC) combined with ultraviolet absorbance detection, solid-phase extraction and mass spectrometry (MS). These alkaloids were hydrolyzed rapidly in alkaline solution (half lives (t1/2) five months) and were unstable in solutions of methanol and ethanol (t1/2<one month). These alkaloids were separated on an octadecylsilica column with isocratic elution using a solvent mixture of tetrahydrofuran and 0.2% trifluoroacetic acid (14:86, v/v), which was found to be the optimal solvent of the elution systems examined. Calibration curves with UV detection were linear on injection of amounts ranging from 2.5 to 500 ng, and the limit of detection was 1 ng (S/N=3). These four alkaloids in aqueous solution were recovered almost totally by solid-phase extraction using the styrene polymer resin, Sep-Pak Plus PS-1, and were eluted using a mixture of acetonitrile and hydrochloric acid. These Aconitum alkaloids were confirmed by HPLC coupled with fast atom bombardment MS, giving their protonated molecular ions as base peaks. These alkaloids were detected by HPLC with UV detection from blood samples spiked with more than 50 ng ml(-1) of alkaloids, but were not detectable from urine samples spiked with 5 microg ml(-1) of alkaloids because of severe sample interference.

Aconitine↗

PubMed1997

Cloning and sequencing of the gene encoding the plasma membrane H(+)-ATPase from an acidophilic red alga, Cyanidium caldarium.

A cDNA containing an open reading frame encoding the putative plasma membrane H(+)-ATPase in an acidophilic red alga, Cyanidium caldarium, was cloned and sequenced by means of PCR and Southern hybridization based on homologous sequences of P-type ATPases found in other organisms. The cloned cDNA is 3300 bp in length, containing a 2865 bp open reading frame encoding a polypeptide of 955 amino acids which has a predicted molecular mass of 105,371. The deduced amino acid sequence was found to be more homologous to those of P-type H(+)-ATPases from higher plants than that from the green alga Dunaliella bioculata.

Amino Acid Sequence↗

PubMed1997

Identification of domains on the extrinsic 33-kDa protein possibly involved in electrostatic interaction with photosystem II complex by means of chemical modification.

The extrinsic 33-kDa protein of photosystem II (PSII) was modified with various reagents, and the resulting proteins were checked for the ability to rebind to PSII and to reactivate oxygen evolution. While modification of more than eight carboxyl groups of aspartyl and glutamyl residues with glycine methyl ester did not affect the rebinding and reactivating capabilities, modification of amino groups of lysyl residues with either N-succinimidyl propionate or 2, 4,6-trinitrobenzene sulfonic acid or modification of guanidino groups of arginyl residues with 2,3-butanedione resulted in a loss of rebinding and reactivating capabilities of the 33-kDa protein. Moreover, the number of lysyl and arginyl residues susceptible to modification was significantly decreased when the protein was bound to PSII as compared with when it was free in solution, whereas the number of carboxyl groups modified was little affected. These results suggested that positive charges are important for the electrostatic interaction between the extrinsic 33-kDa protein and PSII intrinsic proteins, whereas negative charges on the protein do not contribute to such interaction. By a combination of protease digestion and mass spectroscopic analysis, the domains of lysyl residues accessible to N-succinimidyl propionate or 2,4, 6-trinitrobenzene sulfonic acid modification only when the 33-kDa protein is free in solution were determined to be Lys4, Lys20, Lys66-Lys76, Lys101, Lys105, Lys130, Lys159, Lys186, and Lys230-Lys236. These domains include those previously reported accessible to N-hydroxysuccinimidobiotin only in solution (Frankel and Bricker (1995) Biochemistry 34, 7492-7497), and may be important for the interaction of the 33-kDa protein with PSII intrinsic proteins.

Amino Acid Sequence↗

PubMed1997

Actions of S-nitrosocysteine in the nucleus tractus solitarii are unrelated to release of nitric oxide.

Cardiovascular effects elicited by microinjection of L-S-nitrosocysteine in the nucleus tractus solitarii (NTS) were compared and contrasted with those produced by the dextroisomer, other nitric oxide donors and nitric oxide itself. L-S-nitrosocysteine produced dose-related decreases of arterial pressure and heart rate. In contrast, D-S-nitrosocysteine, S-nitrosoglutathione, glyceryl trinitrate, and sodium nitroprusside produced minimal responses that were not dose-related. Likewise, injection of cystine and nitric oxide, two products of S-nitrosocysteine breakdown, produced no significant response. Headspace analysis using chemiluminescence revealed that L- and D-S-nitrosocysteine released identical amounts of nitric oxide when exposed to homogenates of whole rat brain. Responses to L-S-nitrosocysteine were not affected by local injection of oxyhemoglobin or the nitric oxide synthase inhibitor L-nitroarginine methylester. Although injection of L-cysteine into the NTS produced responses similar to those seen with injection of L-S-nitrosocysteine, blockade of excitatory amino acid receptors with kynurenic acid inhibited responses to cysteine but not those to the nitrosothiol. The study demonstrates that S-nitrosocysteine is biologically active in the NTS. Its action is independent of release of nitric oxide from the nitrosothiol but may be mediated through stereoselective sites on target neurons.

Animals↗

PubMed1997

Cloning of the gene for monogalactosyldiacylglycerol synthase and its evolutionary origin.

Monogalactosyldiacylglycerol (MGDG) synthase (UDPgalactose:1,2-diacylglycerol 3-beta-D-galactosyltransferase; EC 2.4.1.46) catalyzes formation of MGDG, a major structural lipid of chloroplast. We cloned a cDNA for the synthase from cucumber cDNA library. The full-length cDNA clone was 2142 bp, and it contains a 1575-bp open reading frame encoding 525 aa. The open reading frame consists of the regions for a mature protein (422 aa; Mr of 46,552) and transit peptide to chloroplast (103 aa). Although the molecular weight of mature protein region matched that purified from cucumber cotyledons, it was quite different from those purified from spinach (approximately 20 kDa) reported by other groups. The mature region of the protein was expressed in Escherichia coli as a fusion protein with glutathione S-transferase. The expression in E. coli showed that the protein catalyzed MGDG synthesis very efficiently. Therefore, we concluded that the cDNA encodes MGDG synthase in cucumber. In addition, the deduced amino acid sequence of the MGDG synthase cDNA showed homology with MurG of Bacillus subtilis and E. coli, which encode a glycosyltransferase catalyzing the last step of peptidoglycan synthesis in bacteria. This sequence homology implies that the machinery of chloroplast membrane biosynthesis is evolutionarily derived from that of cell wall biosynthesis in bacteria. This is consistent with the endosymbiotic hypothesis of chloroplast formation.

Amino Acid Sequence↗

PubMed1997

The regulatory effect of fermentable sugar levels on the production of leukotoxin by Actinobacillus actinomycetemcomitans.

The relationship between sugar availability and RTX (repeats in toxin) cytotoxin (leukotoxin) production in the periodontopathic bacterium, Actinobacillus actinomycetemcomitans, was investigated using a chemostat. A actinomycetemcomitans 301-b produced significant amounts of leukotoxin in anaerobic fructose-limited chemostat cultures at a dilution rate of 0.15 h-1 and at pH 7.0. When the growth limitation was relieved by pulsing the cultures with 50 or 150 mM fructose (final concentrations), leukotoxin production immediately stopped and the amount of cellular leukotoxin decreased until the culture was returned to fructose-limited conditions. Leukotoxin synthesis was also repressed in the chemostat cultures by pulsing with glucose but not with the non-fermentable sugar analog, alpha-methyl-D-glucoside. Leukotoxin production was also repressed by fructose in chemostat cultures of ATCC 33384, which is generally recognized as a non-leukotoxin-producing or minimally leukotoxic strain.

Aggregatibacter actinomycetemcomitans↗

PubMed1997

Significance of Helicobacter pylori infection as a risk factor in gastric cancer: serological and histological studies.

We conducted a case-control study to examine the association of Helicobacter pylori infection as a risk factor in gastric cancer in the Japanese population. Serum IgG antibodies for Helicobacter pylori were determined in 55 consecutive patients with gastric cancer and in 75 age- and sex-matched mass survey subjects and 57 age- and sex-matched cancer-free patients with conditions considered at a high risk for development of gastric cancer (precancerous condition). We examined the histology in all subjects and particular focus was placed on the extent of Helicobacter pylori-associated gastritis. The seroprevalence of Helicobacter pylori in gastric cancer patients (82%) and those with a precancerous condition (89%) was significantly higher (P < 0.005) than that in the mass survey subjects (60%). Positive relative risk associations were found for patients with gastric cancer (odds ratio, 3, with 95% confidence intervals of 1.69-5.33) and those with a precancerous condition (odds ratio, 5.66, with 95% confidence intervals 2.66-12.03). Significant differences were found when comparisons were made among the case-control groups who were H. pylori-positive and had inflammatory cell infiltration (P = 0.0127). The characteristics of Helicobacter pylori in histologically examined gastric mucosa showed differences between Helicobacter pylori-infected and uninfected persons in all groups. However, for none of these groups was there a significant differences between background mucosa for Helicobacter pylori-infected persons with or without gastric cancer. Helicobacter pylori seroprevalence is strongly associated with an increased risk of gastric cancer and with a precancerous condition; histological investigation did not define additional factors that might be associated with increased cancer risk.

Adult↗

PubMed1997

Technetium-99m-sestamibi scintimammography of benign and malignant phyllodes tumors.

We presented two cases of phyllodes tumor of the breast examined by 99mTc-sestamibi (MIBI) two-phase scintimammography. In the case with malignant phyllodes tumor, 99mTc-MIBI accumulation was recognized on both early and delayed images. In the case with benign phyllodes tumor, however, 99mTc-MIBI accumulation was recognized on only the early image. 99mTc-MIBI delayed imaging may have the potential to distinguish between benign and malignant phyllodes tumors.

Breast Neoplasms↗

PubMed1997

Three patients with bilateral breast tumors examined by technetium-99m-sestamibi scintimammography.

We presented three patients with bilateral breast tumors (one with breast cancers, one with breast cancer and fibroadenoma, and one with fibroadenomas) examined by 99mTc-hexakis 2-methoxy-isobutylisonitrile (MIBI) scintimammography. In all cases 99mTc-MIBI uptake was recognized only in the breast cancers. 99mTc-MIBI scintimammography was useful in evaluating bilateral breast tumors since preoperative diagnosis is valuable in determining correct surgical treatment.

Adolescent↗