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Biomedical subjects

H Aoki

Publications and source records attributed to H Aoki.

At least 307 records · Page 17Linked to original sources
PubMed1992

Effects of antacids, ferrous sulfate, and ranitidine on absorption of DR-3355 in humans.

This study examined the effects of widely used antacids (aluminum hydroxide, magnesium oxide, and calcium carbonate), ferrous sulfate, and ranitidine on the absorption of a fluorinated quinolone, (-)-(S)-9-fluoro-3-methyl-10-(4-methyl-1-piperazinyl)-7-oxo-2,3-dihydro- 7H- pyrido-[1,2,3,-de][1,4]benzoxazine-6-carboxylic acid hemihydrate (DR-3355), in healthy male volunteers enrolled in three separate randomized crossover studies. Study 1 used 100-mg doses of DR-3355 and concurrent doses of aluminum hydroxide (1 g) or magnesium oxide (500 mg), while study 2 used DR-3355 (100 mg) and concurrent ferrous sulfate (160 mg) or calcium carbonate (1 g). Study 3 used DR-3355 (100 mg) and concurrent ranitidine (150 mg). Each study included control doses of DR-3355 (100 mg) alone. When aluminum hydroxide, ferrous sulfate, and magnesium oxide were coadministered with DR-3355, the relative bioavailability of DR-3355 was decreased to 56, 81, and 78%, respectively, of that for DR-3355 (100 mg) alone. Urinary excretion of DR-3355 was also significantly decreased by coadministration of these drugs. Thus, the magnitude of the decrease in the area under the concentration-time curve for DR-3355 varied among antacids, and the ranking of their inhibitory effects correlated with previously reported rankings of stability constants for chelate formation. DR-3355 bioavailability was not influenced by the concurrent administration of calcium carbonate and ranitidine, indicating that changes in gastric pH do not affect DR-3355 absorption.

Adult↗
PubMed1992

Plasma atrial natriuretic factor in patients with acute myocardial infarction.

To examine whether atrial natriuretic factor (ANF) is secreted adequately in the early phase of myocardial infarction, plasma ANF concentration and clinical parameters, including hemodynamic variables, were studied in 118 patients with acute myocardial infarction (AMI). The patients were divided into 2 subgroups according to the absence (group A, n = 41) or presence (group B, n = 77) of a history of valvular heart disease, previous myocardial infarction, hypertension, or renal failure. Although no significant difference in atrial pressure after the infarction was found between the 2 groups, the plasma ANF level was significantly lower in group A than in group B (76 +/- 6 vs. 185 +/- 26 pg/ml; mean +/- SEM, p < 0.01). Plasma ANF was correlated with pulmonary capillary wedge pressure in group B (r = 0.54, p < 0.001), whereas no relationship with hemodynamic parameters was observed in group A. In 56 of the 118 patients (group A, n = 18; group B, n = 38), the pulmonary arterial plasma level was significantly higher in group A (p < 0.05), whereas the difference was not significant in group B. Seven of the 8 expired cases among these 56 patients had peripheral plasma ANF levels of more than 150 pg/ml, which were higher than those in pulmonary arterial plasma. These observations suggest firstly that the plasma level of ANF is lower in patients with a new onset of myocardial infarction compared to those with a history of cardiac or renal diseases, and secondly that stimulated ANF release originates not only from the right side of the heart, but also from additional site(s), particularly in patients with chronic ventricle overload and a poor prognosis.

Atrial Function, Right↗
PubMed1992

[Amino acid metabolism in surgical stress].

Amino acid metabolism under surgical stress, injury or infection was reviewed from the literature. The glucose-alanine cycle in coupling with branched chain amino acids (BCAA) metabolism plays a central role for gluconeogenesis, in such a catabolic state. Glutamine is as important as alanine for sparing glucose and furthermore for intestinal repair. Changes in plasma amino acid concentration and clearance following hepatectomy are described, and effects of BCAA solution are evaluated. It was suggested that BCAA improved the Fischer ratio by increasing, not only plasma BCAA level, but also AAA clearance.

Alanine↗
PubMed1992

Intramedullary spinal cord metastasis from lung cancer presenting with paraparesis: an autopsied case.

A 75-year-old male presented with paraparesis and pain in the thighs, which progressed rapidly. Five days later, he was unable to stand or to void urine. A lung cancer was found in the right upper lobe. A spinal cord metastasis from the lung cancer was suspected from the neurologic and pulmonary findings. After 2 weeks, motor dysfunction and a total sensory deficit were observed below the lumbar region, and the patient developed pneumonia, which resulted in death. Autopsy showed an extensive intramedullary metastasis at the third lumbar segment of the spinal cord. Histology revealed poorly differentiated adenocarcinoma of the lung.

Adenocarcinoma↗
PubMed1992

[Decision analysis in therapeutic strategies for small bowel obstructions].

Clinical decision analysis was applied in therapeutic decision-making regarding small bowel obstructions. For strangulation obstruction, the three strategies of immediate surgery, observation of clinical course, and decision according to ultrasonographic findings were analyzed. When mortality rate, morbidity rate, or duration of hospital stay was used as the utility value, decision on the basis of ultrasonographic findings was selected as the most effective strategy, while the strategy of immediate surgery was selected when the rate of intestinal necrosis was used as the utility value. For adhesive obstructions, the three strategies of immediate surgery, conservative treatment with long tube decompression, and long tube decompression with enteroclysis (infusion contrast radiography) were analyzed. The strategy of enteroclysis was selected when morbidity rate and duration of hospital stay were used as utility values, while immediate surgery was selected when recurrence rate of adhesive obstruction was used as the utility value. For obstruction caused by intraabdominal recurrent cancer, operative treatment and conservative treatment were analyzed. The strategy of surgery was selected when rate of obstruction resolved and number of months of survival were used as utility values. Clinical decision analysis is valuable in quantitatively assessing individual variables affecting therapeutic decision-making.

Decision Support Techniques↗
PubMed1992

[Perioperative renal functions in patients with chronic renal disease].

Renal function was studied in patients with compensated renal failure and in those with slight renal disorder during and after operations focusing on several aggravating factors. After perioperative episodes of hypovolemia, bleeding and shock, the levels of urine beta 2 microglobulin and FENa were elevated, showing the abnormal renal tubule functions. Elevation of NAG and the decrease of Ccr were observed, showing the organic damage on the renal tubular cell and the influence on GFR. These aggravating factors should be eliminated to prevent the irreversible renal changes.

Acetylglucosaminidase↗
PubMed1992

[Three cases of perioperative brain infarction].

In recent years, the number of elderly patients who require operation has been increasing. We experienced three patients with perioperative brain infarction, occurring respectively, during the preoperative period, just after operation, and three days after operation. All three patients had more than one of the common risk factors for cerebrovascular accidents, including hypertension, advanced age, hyperfibrinogenemia, diabetes mellitus, and past history of cerebrovascular accident. On the basis of our experience with these three patients, we suggest the following: (1) Waiting period of elective surgery should be reconsidered in some cases with a past history of stroke. (2) Some high-risk patients may benefit from anticoagulative or antiaggregative drugs (e.g. low-molecular dextran or prostaglandin E1) to prevent brain ischemia. (3) Abrupt control of hypertension or diabetes mellitus status undoubtedly adversely affects the patient's general condition; and (4) A practical monitoring system to detect regional brain ischemia during operation under general anesthesia should be developed.

Aged↗
PubMed1992

[A new method for preoperative evaluation of platelet aggregation: Part I].

Newly introduced antiplatelet drugs such as ticlopidine or cilostazol are often administered to preoperative patients. However, how to evaluate the effect of these drugs on anesthetic management remains unsettled. The platelet aggregation test was performed on 20 operative patients, and the aggregation patterns are classified into five categories. The platelet aggregation is almost unchanged in some patients, and slightly depressed in others. The new classification of platelet aggregation patterns that we introduced for preoperative evaluation seems to be a good indicator of platelet function in patients medicated with antiplatelet drugs.

Humans↗
PubMed1992

[A new preoperative evaluation of platelet aggregation--Part II].

With the new platelet function test which we reported in the first paper, the platelet aggregation was evaluated in 50 patients, and the comparison with the results of bleeding time was made in 20 cases. There was no statistical correlation between the bleeding time and the platelet aggregation. The bleeding time has been considered as an indicator of platelet function and is included in a preoperative check list. However, its result depends on the amount of platelets and the endothelial factor, and the reliability of bleeding time on platelet function is considered small, especially in patients medicated with antiplatelet drugs. For such patients, the platelet aggregation test is essential. The present study demonstrated that the patient belonging to grade-1 were resistant to hemostasis during the operation. Taking into the surgical and anesthetic depression on the platelet function into consideration, the patients below grade-2 are risky for the surgery.

Adult↗
PubMed1991

Endothelin induces the Ca(2+)-transient in endothelial cells in situ.

Using front-surface fluorometry of fura-2 and valvular strips of the pig aorta, we recorded changes in the cytosolic Ca2+ concentration, [Ca2+]i, of endothelial cells in situ, quantitatively, and investigated the effects of endothelin-1 and -3 on these endothelial cells. Both endothelin-1 and -3 elevated [Ca2+]i of a peak (the first phase) and sustained type. This first phase is considered to be due to a release of Ca2+ from intracellular storage sites. The sustained phase depended on extracellular Ca2+ and is considered to be due to an influx of Ca2+ through the plasma membrane. At equimolar concentrations, the peak elevations of [Ca2+]i induced by endothelin-1 were much higher than those induced by endothelin-3. We suggest that, in endothelial cells in situ, endothelin-1 mobilizes stored Ca2+ and may activate Ca(2+)-sensitive pathways, including the release of prostacyclin and endothelium-derived relaxing factors, more potently than does endothelin-3.

Animals↗
PubMed1991

Cloning, sequencing and overexpression of the gene for prokaryotic factor EF-P involved in peptide bond synthesis.

A soluble protein EF-P (elongation factor P) from Escherichia coli has been purified and shown to stimulate efficient translation and peptide-bond synthesis on native or reconstituted 70S ribosomes in vitro. Based on the partial amino acid sequence of EF-P, 18- and 24-nucleotide DNA probes were synthesized and used to screen lambda phage clones from the Kohara Gene Bank. The entire EF-P gene was detected on lambda clone #650 which contains sequences from the 94 minute region of the E.coli genome. Two DNA fragments, 3.0 and 0.78 kilobases in length encompassing the gene, were isolated and cloned into pUC18 and pUC19. Partially purified extracts from cells transformed with these plasmids overrepresented a protein which co-migrates with EF-P upon SDS polyacrylamide gel electrophoresis, and also exhibited increased EF-P mediated peptide-bond synthetic activity. Based on DNA sequence analysis of this gene, the EF-P protein consists of 187 amino acids with a calculated molecular weight of 20,447. The sequence and chromosomal location of EF-P establishes it as a unique gene product.

Amino Acid Sequence↗
PubMed1991

High-performance liquid chromatographic determination of (S)-(-)-ofloxacin and its metabolites in serum and urine using a solid-phase clean-up.

A sensitive and selective method for the simultaneous determination of (S)-(-)-ofloxacin [(S)-(-)-OFLX] and its metabolites in serum and urine was developed using isocratic high-performance liquid chromatography with a specific solid-phase extraction procedure. (S)-(-)-OFLX and its metabolites, desmethyl-(S)-(-)-OFLX and (S)-(-)-OFLX N-oxide, were eluted from a C8 solid-phase column with recoveries of more than 98%. These compounds were separated and determined by means of a reversed-phase column with fluorimetric detection. Validation studies showed that the results were linear for (S)-(-)-OFLX in serum over the range 10-1200 ng/ml and in urine over the range 1-200 micrograms/ml. Analysis for (S)-(-)-OFLX and its metabolites showed good precision and accuracy with a relative standard deviation of less than 6%.

Chromatography, High Pressure Liquid↗
PubMed1991

Primitive neuroectodermal tumor of the leptomeninges.

Primitive neuroectodermal tumor (PNET) without an obvious intraparenchymal mass lesion and with diffuse spread in the subarachnoid space is rare. We report such a rare case and discuss the computed tomography (CT) and magnetic resonance (MR) features.

Adolescent↗
PubMed1991

Dumbbell neurogenic tumor of the mediastinum: a report of three cases undergoing single-staged complete removal without thoracotomy.

Of a total thirteen patients who underwent surgery for a neurogenic tumor in the posterior mediastinum 4 (30.8 per cent) presented with dumbbell type development of the tumor. Along with a comparatively greater incidence in the number of cases of dumbbell neurogenic tumors in the posterior mediastinum, resection has also recently become more popular, necessitating the establishment of a standard operative approach for this type of tumor. We successfully removed dumbbell neurogenic tumor from the posterior mediastinum in our 3 most recent cases via a dorsal approach by virtue of a laminectomy and resection of a small portion of the neighbouring rib root without opening the parietal pleura at all. These three patients were a 14 year old female, a 54 year old male and a 68 year old female, respectively, and the largest diameter in cm and level of origin of the tumors were 5.5 at Th 1 in case 1, 3.0 at Th 2 in case 2 and 3.7 at Th 11 in case 3. The operative approach described herein was easy to perform, felt secure and was less invasive and better tolerated by the patients than the thoracotomy approach. Avoiding a thoracotomy in such cases has many advantages to enumerate, but does not seem to have been clearly aimed at by others to date. We therefore propose our technique as a standard approach for dumbbell neurogenic tumors in the posterior mediastinum.

Adolescent↗
PubMed1991

Production and characterization of a monoclonal antibody to the v-mos oncogene protein.

Valuable information about proto-oncogenes and their physiological functions has been obtained by studying their expression in normal cells. However, the protein product of the c-mos gene, the cellular homologue of the transforming gene (v-mos) of Moloney murine sarcoma virus, has not been detected in normal mouse cells or tissues. Here, we have constructed a v-mos expression vector, pRI-delta mos, which directs the synthesis of a truncated v-mos gene product, a protein A fusion protein. Using the truncated v-mos oncoprotein produced in Escherichia coli as immunogen, we prepared anti-v-mos monoclonal antibodies (MAbs). In immunoblotting assays, the MAb was reactive with v-mos oncoprotein and detected bands at 43 KDa or 39 kDa in the tissue extract of mouse testes or ovaries, respectively, in which the c-mos protooncogene mRNA is expressed. These results demonstrate that the v-mos MAb obtained is suitable for elucidating the physiological functions of v-mos gene product and may also be utilized to detect c-mos gene product at the cellular level.

Animals↗