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Biomedical subjects

T Ohkawa

Publications and source records attributed to T Ohkawa.

At least 109 records · Page 6Linked to original sources
PubMed1993

[Some effects of pH, diuretics and organic acids on the uptake of oxalate in a renal tubular cell line (LLC-PK1)].

The effects of changes in extracellular pH and treatments with diuretics or some organic acids on the uptake of oxalate were studied in an epithelial cell line of renal origin (LLC-PK1 cells). The oxalate uptake into the cells exhibited a marked sensitivity to extracellular, pH, in the present results with acidic pH stimulating and alkaline pH inhibiting the DIDS sensitive uptakes. The uptake of oxalate was clearly inhibited by DIDS, proportionally to the concentrations from 10 microM to 1 mM. Furosemide, chlorothiazide, probenecid and acetazolamide inhibited the oxalate uptake significantly. Probenecid has the most potency on the inhibition of the uptake in high concentrations, and acetazolamide needed a high concentration for the small effect. However, allopurinol has no effect on the uptake as well as dicarboxylates (malate, succinate and phenyl succinate) and organic acids (urate and para-amino hippurate). We discussed the mechanisms of the inhibition against the oxalate uptake concerning with each drug. It was suggested that probenecid may inhibit the oxalate carriers directly, while furosemide, chlorothiazide and acetazolamide may inhibit then by the direct actions and some secondary effects which are provided by those drugs.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMed1993

[Adhesion of calcium oxalate crystal to Madin-Darby canine kidney cells: quantitative determination and effects of glycosaminoglycans (GAG) and cell injuries on adhesion].

The present investigation was designed to study adhesion of calcium oxalate crystals on the surface of intact MDCK cells quantitatively, and to estimate the effects of glycosaminoglycans (GAGs) and cell injuries on these adhesions. Calcium oxalate monohydrate (COM) crystals adhere to the cell surface by an active force, and the attachment is in a time and concentration dependency with plateau. Pre-treatments with low concentration of GAGs (chondroitin sulphate C, hyaluronic acid, heparan sulphate, heparin and sodium pentosan polysulphate) produce significant reductions of the adhesion. There are significant decreases of the adhesions with pre-treatments of Triton-X100, 0.1 N HCl and gentamicin. These phenomena might be induced by some alterations of cell surface structures or characters. The current quantitative system on MDCK cells should serve as a useful model for the investigations of interactions with crystals and tubular cells. Our studies may also support the hypothesis of attachment of microcrystals to the cellular membrane, which is one of the most important and the earliest process of the pathophysiology of kidney stone.

Animals↗
PubMed1993

[Inhibitory activity of urinary macromolecule upon calcium oxalate crystal aggregation using an aggregometer].

We studied inhibitory activity of urinary macromolecule upon the calcium oxalate crystal aggregation using an aggregometer. We have developed an aggregometric assay method to measure the anti-aggregation ratio of calcium oxalate crystals in vitro. The macromolecular fraction of urine with a molecular weight above 5,000 was isolated by PD-10 (Sephadex G-25M, Pharmacia) and made up to three-fold by Centriprep Concentrator (Amicon). The urinary macromolecular substances of recurrent calcium stone formers showed much less inhibitory activity than those of healthy controls. There were no significant relationships between the anti-aggregation activity and the concentration of urinary proteins and other parameters concerning with stone diseases. It was speculated that some proteins, molecular weight about 10,000-30,000, might inhibit the aggregation vigorously based on the result of gel filtration (Superrose 12 HR, 20/50, Pharmacia) technique used in a healthy man's 24 hours urine. Thus, it supports that some urinary macromolecules are important during the phase of aggregation of calcium oxalate crystals, and that the feeble activity to present the aggregation may be one of the cause of calcium oxalate stone formation.

Adult↗
PubMed1993

[A case of urinary retention due to ovarian dermoid cyst in a female infant].

The patient was a 20-month-old girl. She visited some pediatric clinic with the chief complaint of voiding difficulty and miction pain from October 5, 1991. Excretory urogram, abdominal ultrasound and computed tomographic scan revealed a retrovesical mass which compressed the urinary bladder antero-superiorly. She was referred to our hospital for further evaluation. Physical examination disclosed a fist-sized tumor in her lower abdomen, which persisted after bladder emptying. Cystoscopy revealed elongation of the urethra and elevation of the bladder base. Tumor markers and endocrine examination were normal. Magnetic resonance imaging at 2 weeks after admission revealed that the retrovesical tumor had been translocated cranial to the bladder. Operation was done on October 29, 1991. The tumor originated from the right ovary and was 6.2 x 5.0 x 5.0cm in size and 60g in weight. The cut surface of the surgical specimen included the fatty tissue and hair, and the pathological diagnosis was an ovarian dermoid cyst. This is the youngest case of ovarian dermoid cyst presenting as urinary retention in the Japanese literature. The mechanism of urinary retention due to infantile gynecological disease is discussed.

Dermoid Cyst↗
PubMed1992

Determination of eperisone in human plasma by gas chromatography-mass spectrometry.

A gas chromatographic-mass spectrometric method was developed to determine eperisone hydrochloride, 4'-ethyl-2-methyl-3-piperidinopropiophenone hydrochloride, in human plasma over the concentration range 0.2-40 ng/ml. Excellent sensitivity was achieved by selection of a favorable fragment ion, m/z 98, of eperisone and reduction of heat decomposition of eperisone by using a splitless injector and a shortened capillary column. The method described here allows the determination of plasma concentrations as low as 0.2 ng/ml, the concentration attained 6 h after a single oral administration of 50 mg. At eperisone hydrochloride concentrations higher than 0.5 ng/ml, the mean inter-day variation of accuracy of the assay was less than 12%.

Calibration↗
PubMed1992

1H-NMR study on the chitotrisaccharide binding to hen egg white lysozyme.

Interaction between hen egg white lysozyme and chitotrisaccharide was investigated by 1H-NMR spectroscopy using partially acetylated chitotrisaccharides and chemically modified lysozyme. Monoacetyl (GlcN-GlcN-GlcNAc), diacetyl (GlcN-GlcNAc-GlcNAc), or triacetyl chitotrisaccharide [(GlcNAc)3] was added to the lysozyme solution, and the changes in the 1H-NMR signals of the lysozyme were analyzed. Although many of the resonances were affected by addition of the saccharide, the most remarkable effect was seen on the signal of Trp28 C5H which is in a hydrophobic box adjacent to the saccharide-binding site. The signal shifted upfield by 0.2 ppm upon (GlcNAc)3 binding, whereas the chemical shift change of the signal resulting from binding of GlcN-GlcNAc-GlcNAc or GlcN-GlcN-GlcNAc was smaller than that resulting from (GlcNAc)3 binding. When the Asp101-modified lysozyme was used instead of the native lysozyme, the chemical shift change of the Trp28 C5H signal resulting from (GlcNAc)3 binding was also smaller than that for the native lysozyme. The chemical shift change of the signal reflects the conformational change of the hydrophobic box region which should synchronize with the movement of the binding site resulting from the saccharide binding. Therefore, the conformational change resulting from the saccharide binding might be reduced when the sugar residues located at binding subsites A and B of the lysozyme are deacetylated, as well as when Asp101 interacting with the sugar residues at the same subsites is modified.

Animals↗
PubMed1992

Excessive production of transforming growth-factor beta 1 can play an important role in the development of tumorigenesis by its action for angiogenesis: validity of neutralizing antibodies to block tumor growth.

Angiogenesis is an important part of tumor growth in vivo. We used the transfected Chinese hamster ovary (CHO) cells that overproduced recombinant transforming growth-factor beta 1 (TGF-beta 1) to examine the possible role of this factor in tumor growth and angiogenesis in a nude mouse model. The in-vitro proliferation of TGF-beta 1-transfected CHO cells was unaffected by the treatment of either recombinant TGF-beta 1 or an anti-TGF-beta 1 antibody. The TGF-beta 1-transfected cells grew more rapidly than the parental CHO cells when injected subcutaneously into nude mice. The tumors derived from the TGF-beta 1-transfected cells showed prominent tumor-associated angiogenesis, whereas the parental cells produced tumors without such angiogenesis. In addition, an anti-TGF-beta 1 neutralizing antibody was able to inhibit both growth and angiogenesis in the tumors derived from TGF-beta 1-transfected cells. These findings suggest that the overproduction of TGF-beta 1 by tumor cells can contribute to neovascularization and may help promote tumor development in vivo.

Animals↗
PubMed1992

Effects of local anesthetics on the Chara plasmalemma.

The effects of lidocaine, tetracaine, procaine and bupivacaine (less than 1000 microM) on the Chara corallina internodal cell were studied. These local anesthetics depolarized the membrane at rest, while they affected the rising phase and the peak level of action potential not appreciably. Instead, they prolonged the time course of the falling phase of action potential as slowly as the repolarization was imperfect, even after enough lapse beyond the refractory period. Consequently, an action potential appeared to enhance the degree of depolarization at rest. Such a depolarization with stimulus/excitation was named use-dependent depolarization, while the depolarization without excitation, the resting one. The order of the potency of the use-dependent depolarization almost coincided with that of the nerve-blocking potency. During depolarization the change in membrane conductance was not simple. However, the conductance-voltage (Gm-Vm) relationship curve in the presence of local anesthetic suggested that depolarization was due to, not only the decrease in the electrogenic H(+)-pump, but also the increase in the diffusion conductance.

Action Potentials↗
PubMed1992

Results of adjuvant chemotherapy for invasive uroepithelial cancer.

Between June 1982 and July 1990, 55 patients (41 with bladder cancers and 14 with renal pelvic or ureteral cancers) who had undergone radical extirpative surgery and/or node dissection for pathological stage pT2-4 and/or nodal disease received adjuvant chemotherapy consisting of cisplatin alone or in combination with other agents. In all, 26 of the bladder-cancer patients also received preoperative chemotherapy consisting of arterial infusion of cisplatin, mitomycin C, and Adriamycin. Adjuvant chemotherapy was performed according to the following protocol. Between June 1982 and July 1987, 30-50 mg/m2 cisplatin either alone or in combination with Adriamycin and 5-fluorouracil (CAF) was given to 35 patients in an induction and maintenance setting for 1 year. After July 1987, short-course cisplatin (70 mg/m2) or cisplatin, etoposide, and Adriamycin combination chemotherapy (CVA) was given to 20 patients. Of the 55 patients, 38 are alive and show no evidence of disease, three are alive with disease, 13 have died of their disease, and 1 has died of an unrelated cause. The 5-year survival of all patients was 65.1%. The survival of the 20 patients who were treated after July 1987 was better than that of the 35 patients who were treated before June 1987. Local recurrence and/or distant dissemination occurred in 16 patients, 13 of whom died of cancer progression. Nausea and vomiting and anorexia occurred in most patients during the administration of cisplatin. Mild to moderate myelosuppression developed in patients who received CAF or CVA combination chemotherapy. Although adjuvant chemotherapy combined with radical surgery seemed to be effective in cases with a pathological stage of pT3a or less, more intensive pre- or postoperative chemotherapy is needed to improve the poor prognosis of patients with deeply invasive uroepithelial cancer.

Aged↗
PubMed1992

[A survey of intestinal parasites of the foreign laborers (Indonesians and Filipinos) in Ishikawa Prefecture].

A survey of intestinal parasites was conducted on 198 foreign workers aged 19-27 from Inodonesia and Philippines. They work for a private company in Ishikawa Prefecture as technical trainee. On the base of stool examination, 94 (71%) out of 133 Indonesians and 48 (74%) of 65 Filipinos had intestinal helminths and/or protozoan infections. The prevalence of Ascaris lumbricoides, Trichuris trichura and Hookworm was 4.5, 64.1, 10.6%, respectively. In addition, the positive rate of the cyst of Entamoeba coli, Endolimax nana, Blastocystis hominis and Giardia lumblia was 11.1, 5.6, 4.5 and 2.0%, respectively. No E. histolytica was found; however, counter current immunoelectrophoresis revealed that one out of 112 sera possessed the antibody against the antigen of HK-9 strain of E. histolytica. Sixty-three cases of trichuriasis were treated with mebendazole at a dose of 200 mg/day x 3 consecutive days. Re-examination revealed that 53 (85.5%) of them were cured.

Adult↗
PubMed1992

Chitinous components of the cell wall of Fusarium oxysporum.

The cell wall of Fusarium oxysporum f. sp. lycopersici was digested with chitinase to analyze the structure of its chitinous components. In spite of a similar acetylation degree of the cell wall components to that of 25-35% acetylated chitosan, only N-acetylglucosamine disaccharide [(GlcNAc)2] was obtained from chitinase hydrolyzate of the fungal cell wall by CM-Sephadex C-25 column chromatography, while (GlcNAc)2 and several types of deacetylated chitooligosaccharides were separated from that of 25-35% acetylated chitosan. The results indicate that N-acetylglucosamine residues in the polysaccharide chains of the fungal cell wall are most likely condensed into some region, while acetylated residues are more scattered in 25-35% acetylated chitosan.

Carbohydrate Sequence↗
PubMed1992

Different susceptibilities to attenuated poliovirus of cynomolgus monkeys from the Philippines and other Southeast Asian countries.

Susceptibilities to attenuated poliovirus of cynomolgus monkeys were assessed by the intraspinal inoculation method with the same single bulk lot as the reference for each of the three poliovirus types. The lesion-inducing virus dose in the spinal cord of 50% of monkeys inoculated (LID50) varied widely from 10(6.4) to lower than 10(2.5), the difference being as much as 10,000-fold, depending on the birth place of the monkey. The birth places of the monkeys used were traced and categorized into the following three districts; the peninsular region, Indonesia and the Philippines. The LID50 value of the attenuated poliovirus in the monkeys from the Philippines were much lower than those in the monkeys from the other two districts.

Animals↗
PubMed1992

[A clinical review of 19 patients with pheochromocytoma].

Nineteen cases of pheochromocytoma were experienced at our department between 1979 and 1990. Nine patients were males and 10 females with an average of 42.4 years old. In 18 patients the tumor was located in the adrenal gland (9 in right, 5 in left and 4 in bilateral adrenal gland), while in one patient whose original tumor had been resected 15 years earlier, the tumor had recurred in the extra-adrenal gland and was surgically extirpated revealing a malignant pheochromocytoma by histological examination. Hypertension was seen in 16 patients; 14 had paroxysmal and 2 had sustained hypertension. In 3 patients, hypertension was not observed. Familial pheochromocytoma was seen in 5 patients. Three patients had Sipple syndrome. Computed tomographic scan and magnetic resonance imaging were very useful techniques in preoperatively localizing the tumor. Even in the cases treated with alpha- or beta-blocker agents preoperatively, significant hypotension was observed immediately after resection of the tumor and treatment with norepinephrine or rapid blood transfusion or both was needed. Although meticulous care with alpha- and beta-blockers is important, surgical treatment of pheochromocytoma should spare the surgeon of unnecessary anxiety.

Adrenal Gland Neoplasms↗
PubMed1992

[Comparison of surgical therapy and combined irradiation in rectal cancer--second report. Effect of irradiation and ACNU on the tumor].

As part of a joint study on preoperative radiotherapy for developing an optimal mode of rectal cancer therapy, ACNU sensitization was studied in a total of 120 cases, with the cooperation of 48 facilities participating nationwide. The following results were obtained. Improvement in depth of invasion was more distinct in the combination preoperative therapy-ACNU group than in the preoperative radiotherapy group, with no other significant differences between the two. This finding suggests that dose and administration method could be improved. White blood cells and platelets were reduced in some cases of the ACNU combination group, but these reductions were not serious enough to impede surgical procedures. In addition, no significant difference in complications was noted between the two.

Adenocarcinoma↗
PubMed1992

[A case of retrovesical fibrosarcoma with severe hypoglycemia].

We report a case of retrovesical fibrosarcoma with severe hypoglycemia. A 67-year-old man was admitted to our hospital with second recurrence of the retrovesical tumor with hypoglycemia. The episodes of hypoglycemia were accompanied by the advance of tumor size. Complete tumor resection with total cystectomy was performed on December 21, 1989, and the tumor was diagnosed histopathologically as fibrosarcoma. Soon after removal of the tumor, hypoglycemia disappeared and the patient has been well without local recurrence or distant metastasis for more than 20 months.

Aged↗
PubMed1991

Clinical study on urothelial tumors of dye workers in Wakayama City.

Between January 1951 and December 31, 1990 urothelial tumors were detected in 112 of 1,085 male dye workers (10.3%) in Wakayama City who were formerly engaged in manufacturing of benzidine and/or beta-naphthylamine. The period from exposure to the chemicals to development of the tumor was a mean of 24.1 +/- 9.4 years. A peak incidence of urothelial tumors was observed also approximately 25 years after the peak period of manufacturing these intermediate products of dyes. The mean period from exposure to such carcinogenic chemicals to the onset of the disease was estimated to be 25 years. Of the 78 patients with primary bladder cancer diagnosed since 1969, 43 (55.1%) had tumors diagnosed mostly as a result of a positive urinary cytology test obtained as part of a screening program and 35 (44.9%) had tumors diagnosed as the result of symptoms. Ten patients (24.4%) in the screened group had been treated with total cystectomy by the last followup examination compared with 17 (50.0%) in the symptomatic group. The 10-year cumulative survival rates were significantly (p less than 0.05) higher in the screened patients (75.1%) than in the symptomatic patients (55.1%). Our results indicate that screening of high risk populations with urinary cytology tests is effective for early diagnosis and treatment of urothelial tumors, and it improves patient prognosis. Furthermore, the biological behavior of occupational urothelial tumors may be different from that of urothelial tumors in the general population.

2-Naphthylamine↗
PubMed1991

Effect of an acute maternal stress on the fetal hypothalamo-pituitary-adrenal system in late gestational life of the rat.

We investigated in this study the response of the fetal hypothalamo-pituitary-adrenal (HPA) system during an acute maternal stress in rats, in order to find out a possible role of developing fetal hypothalamus and to correlate its function to the androgen unbalance during the critical period of sex-specific brain differentiation. Pregnant rats of days 18-22 of gestation were subjected to an acute forced immobilization, and plasma levels of corticosterone (B) and ACTH were measured in mothers and fetuses. Hypothalamic contents of CRH and beta-endorphin (EP), pituitary content of ACTH, and plasma levels of B and ACTH were measured in mothers and fetuses under the maternal stress on day 20 of gestation. By an acute exposure to the 20 minutes' stress, plasma levels of B and ACTH elevated significantly in mothers on each day of gestation. A significant increase of fetal plasma ACTH was detected from day 18 in males, and from day 20 in females. During the maternal stress on day 20 of gestation, hypothalamic contents of CRH and EP decreased significantly in male and female fetuses, when plasma levels of B and ACTH elevated significantly. These results indicate that fetal HPA axis seems to actually respond to the maternal stress during the late gestational period. Further, a release of CRH under the stress together with an activation of EP system in the fetal hypothalamus suggests a possible mechanism regulating the androgen secretion by the fetal hypothalamus via changes of the LH levels.

Adrenocorticotropic Hormone↗