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Biomedical subjects

A Ishida

Publications and source records attributed to A Ishida.

At least 235 records · Page 13Linked to original sources
PubMed1992

Study of the effect of 350-Hz tone exposure on electrophysiological function of the inner ear of guinea pigs.

The effects of noise exposure were studied in fifty-nine 4- to 5-week-old albino Hartley guinea pigs with normal hearing (body weight 250-300 g). The following experiments and results were carried out: exposure to 350 Hz pure tones at 115 dB for 40 h and exposure to 350 Hz tones at 120 dB for 64 h. In order to investigate the effects of low-frequency tone exposures on the hearing of the guinea pigs, cochlear microphonics (CM), whole nerve action potentials (AP) and endocochlear potentials (EP) were measured. With a high-sound pressure, a decrease was observed in the CM maximum output voltage in the test frequencies of 2, 4 and 6 kHz while the CM threshold (pseudothreshold) of 6 kHz was elevated. Output voltage of the N1 potential of the AP using a 7-kHz tone burst decreased while the threshold of the N1 potential was elevated. An extension of latency and a decrease in the absolute value of the negative potential in EP were also observed.

Acoustics↗
PubMed1992

Recurrent hemoptysis due to aortobronchopulmonary fistula of false aortic aneurysm associated with repair of rupture of the sinus of Valsalva.

A 54-year-old man presented with recurrent hemoptysis of one year duration. Computed tomography (CT) and magnetic resonance imaging (MRI) demonstrated a saccular aneurysm of the ascending aorta. The aneurysm was intraoperatively found to have formed on the superior surface of the site of aortotomy suture placed during previous repair of rupture of the sinus of Valsalva and to have a fistulous communication to the lung. CT and MRI were very useful in the diagnosis of the aneurysm as the cause of hemoptysis.

Aortic Aneurysm↗
PubMed1991

Roles of the D-ribose and 5,6-dimethylbenzimidazole moieties of the nucleotide loop of adenosylcobalamin in manifestation of coenzymic function in the diol dehydrase reaction.

Coenzyme analogs in which the D-ribose moiety of the nucleotide loop was replaced by an oligomethylene group and a trimethylene analog containing imidazole instead of 5,6-dimethylbenzimidazole were synthesized. Coordination of the 5,6-dimethylbenzimidazole to the cobalt atom in these analogs was much weaker than that in cobalamins. The replacement of this base with imidazole did not significantly alter the strength of the coordination to the cobalt atom. 5,6-Dimethylbenzimidazolyl trimethylene and tetramethylene and imidazolyl trimethylene analogs were partially active as coenzymes in the diol dehydrase reaction in this order as judged by kcat, but the others were not active as coenzymes and were weak competitive inhibitors. This indicates that neither the alpha-D-ribofuranose ring nor the functional groups of the ribose moiety are essential for coenzymic function. There was an optimum loop size of the analogs for catalysis and for tight binding to the apoenzyme, which corresponds to the loop size of cobalamins. Therefore, the D-ribose moiety seems important as a spacer to keep the base in the proper position. The reaction with the imidazolyl trimethylene analog as coenzyme was accompanied with concomitant rapid inactivation during catalysis. The inactivation occurred only in the presence of substrate. Upon inactivation with this analog, 5'-deoxyadenosine and a B12r-like species were formed from the adenosyl group and the rest of the analog molecule, respectively, without modification of the apoenzyme. Therefore, it can be concluded that this is a kind of suicide inactivation which occurred from one of the intermediates in the normal catalytic process. The dimethylbenzo moiety of the regular coenzyme thus seems to play an important role in preventing the intermediate complexes from inactivation during catalysis.

Apoenzymes↗
PubMed1991

Failure of T cell receptor V beta negative selection in murine intestinal intra-epithelial lymphocytes.

The intestinal intra-epithelial lymphocytes (IEL) are divided into several subsets on the basis of expression of T cell receptor (TCR) alpha beta and gamma delta, intensity of Thy-1 expression and expression of Lyt-3 chain. To investigate the differentiation pathway of the IEL, we examined the repertoire of V beta segments of T cells in the IEL in BALB/c (H-2d, MIs-1b2a) or AKR/J (H-2k, MIs-1a2b) mice. Among freshly isolated IEL, an appreciable number of T cells bearing V beta 3 or V beta 11, which recognize MIs-2a- or MHC IE-encoded molecules respectively, were detected in BALB/c mice. Similarly, in AKR/J mice, IEL contained appreciable levels of V beta 6-bearing T cells. V beta 3- or V beta 11-bearing T cells in the IEL in BALB/c mice increased to a significant level when incubated with staphylococcal enterotoxin A which specifically stimulates V beta 3- and V beta 11-bearing T cells. Most of IEL without clonal deletion expressed Lyt-2 but not Lyt-3 antigens. Such T cells were hardly detected in other organs, including liver. Our results indicate that TCR alpha beta-bearing intestinal IEL that have not undergone negative selection may have differentiated outside the thymus, presumably at a local site of the intestine and can respond normally to the signal via their TCR.

Animals↗
PubMed1991

Influence of intake of skim milk from cows immunized with intestinal bacterial antigens on onset of renal disease in (NZB x NZW)F1 mice fed ad libitum or restricted in energy intake.

Autoimmune disease-prone (NZB x NZW)F1 (B/W) female mice are a model of human lupus erythematosus. Immune milk, obtained from cows immunized with various intestinal bacterial antigens, was given to B/W mice as a component of diets beginning at 8 wk of age. Diets were fed ad libitum or restricted to 60% of ad libitum energy intake. Controls were fed commercial skim milk. In B/W mice fed ad libitum, the titers of anti-single-stranded DNA antibodies were significantly lower in immune milk-fed mice at 4 and 6 mo of age. Onset of proteinuria was delayed and life span was significantly prolonged by immune milk feeding. Surface phenotypes of the T cells and levels of the responsiveness of lymphocytes to mitogens were not changed by immune milk feeding. The B/W mice restricted to 60% of ad libitum energy intake, which preserved immune responsiveness, had not developed proteinuria by 14 mo of age, irrespective of immune milk feeding or control milk feeding. However, at 10 mo of age, the level of plasma antibodies against intestinal bacteria was significantly higher in energy-restricted mice fed control milk than in those fed immune milk or in mice fed ad libitum.

Animals↗
PubMed1991

New mathematical definition and calculation of axial rotation of anatomical joints.

In the field of joint kinematics, clinical terms such as internal-external, or medical-lateral, rotations are commonly used to express the rotation of a body segment about its own long axis. However, these terms are not defined in a strict mathematical sense. In this paper, a new mathematical definition of axial rotation is proposed and methods to calculate it from the measured Euler angles are given. The definition and methods to calculate it from the measured Euler angles are given. The definition is based on the integration of the component of the angular velocity vector projected onto the long axis of the body segment. First, the absolute axial rotation of a body segment with respect to the stationary coordinate system is defined. This definition is then generalized to give the relative axial rotation of one body segment with respect to the other body segment where the two segments are moving in the three-dimensional space. The well-known Codman's paradox is cited as an example to make clear the difference between the definition so far proposed by other researchers and the new one.

Biomechanical Phenomena↗
PubMed1991

Effects of 250 and 500 Hz tone exposure on the inner ear of guinea pigs as determined by electrophysiological techniques.

The electrophysiological study of cochlear microphonics (CM), whole nerve action potential (AP) and endocochlear potential (EP) were examined. (1) With the extension of the exposure time of 500 Hz tone, a decrease of CM maximum output voltage in test frequency from 2 to 6 kHz was observed. (2) N1 potential of AP decreased very significantly by 500 Hz tone exposure. (3) A very pronounced decrease of the absolute value of the negative potential of the EP in 500 Hz exposure was seen.

Action Potentials↗
PubMed1991

Sequential appearance of T-cell receptor gamma delta- and alpha beta-bearing intestinal intra-epithelial lymphocytes in mice after irradiation.

We have previously reported that T-cell receptor (TcR) gamma delta-bearing T cells precede TcR alpha beta-bearing T cells in appearance in the thymus after whole-body irradiation. In the present study, the kinetics of appearance of intestinal intra-epithelial lymphocytes (IEL) was examined in mice after whole-body irradiation with a lethal dose of 9.5 Gy or with a sublethal dose of 6 Gy. The number of CD3+ IEL decreased to the lowest value 4 days after irradiation with 9.5 Gy, and thereafter increased to half as many as the normal level by day 7. Thy-1+TcR alpha beta- IEL and Thy-TcR alpha beta- IEL recovered considerably by day 7 after the irradiation, whereas Thy-1+TcR alpha beta+ IEL and Thy-1+TcR alpha beta+ IEL hardly recovered at this stage. All mice died within 12 days after irradiation with a lethal dose of 9.5 Gy. On the other hand, when irradiation dose was decreased to 6 Gy, all mice survived beyond 40 days after irradiation. The number of CD3+ IEL recovered to the normal level by 10 days after irradiation with 6 Gy. Consistently with the results in mice irradiated with a lethal dose, the first cells to increase in IEL of mice irradiated with a sublethal dose were TcR gamma delta+ IEL expressing Thy-1 antigen. The number of Thy-1+TcR gamma delta+ IEL increased to approximately two-fold as many as that in normal mice by day 10, while TcR alpha beta+ IEL began to increase in number from day 20 after irradiation and recovered to the normal level by day 40 after irradiation. Thus, sequential appearance of TcR gamma delta+ and TcR alpha beta+ IEL was evident after irradiation, similar to that seen in the thymus after irradiation. The IEL on day 10 after a sublethal irradiation, which is composed mainly of Thy-1+TcR gamma delta+ IEL, exhibited a strong cytolytic activity against P815 in the presence of anti-CD3 mAb, suggesting that the early appearing Thy-1+TcR gamma delta+ IEL may play important roles in epithelial immunity at an early stage after irradiation.

Animals↗
PubMed1991

A stimulating electrode easily attached to and detached from the phrenic nerve.

An electrode system is developed for temporary diaphragm pacing. It is divided into four parts: an electrode complex, a tube, a branch for a lead and a syringe. Stainless steel electrodes are put forward and pulled back by pressure produced by the syringe so that they can be easily attached to and detached from the phrenic nerve. Experiments show that the system works well, the nerve is successfully stimulated and no nerve damages are visually observed.

Animals↗
PubMed1991

[A case of Ullrich disease with distinct pathological change of muscular dystrophy].

A case of Ullrich disease was presented. The patient was a 3-year-old girl with torticollis, generalized muscle weakness and acroatonia since birth. High-arched palate, protruded calcaneus, and mild contracture of proximal joints were also recognized. Intellectual development was normal. Serum level of CPK was slightly increased. In histological and histochemical examinations of quadriceps femoris muscle, proliferated connective tissue, marked variation in the muscle fiber diameter, and a lot of degenerated and regenerated fibers were recognized. Minimal injury easily causes subcutaneous hemorrhage, but no abnormality was found in the structure of collagen.

Child, Preschool↗
PubMed1991

[Multiple calcified adrenal myelolipoma suggestive of association of primary aldosteronism: report of a case].

We report a case of adrenal myelolipoma with multiple calcification and hypertension. A 69-year-old woman visited our hospital with a complaint of right flank pain. Computed tomography demonstrated a right adrenal tumor which was a spherical mass with fat density and multiple calcification. Adrenal scintigraphy of I-131 adosterol demonstrated predominant accumulation of the right adrenal gland. Selective venous sampling disclosed a high aldosterone level (303.7 ng/dl) from the affected side. Right adrenalectomy was performed. Pathological diagnosis revealed adrenal myelolipoma with calcification. After the operation the patient became normotensive. The characteristics of the 12 cases of myelolipoma with calcification we found in the Japanese literature are also briefly reviewed.

Adosterol↗
PubMed1991

[Clinical and pathological studies of the urothelial tumors with inverted proliferation].

We reported a case of inverted papilloma of the bladder, and six cases (two of ureteral cancer and four of bladder cancer) of transitional cell carcinoma with inverted proliferation. These tumors were superficial and pedunculated as well as transitional papilloma or ordinary papillary transitional cell carcinoma though they showed a non-papillary and polyp-like configuration. Moreover, these urothelial cancers with inverted proliferation were thought to be similar to papillary cancer with regard to grading, multiplicity, invasiveness and recurrence. Therefore, transurethral resection or segmental ureterectomy may be recommended for the tumor of low grade malignancy and radical treatment including systemic chemotherapy may be recommended for the tumor of high grade malignancy.

Adult↗
PubMed1990

[Cyclosporin levels in semen of renal transplant patients].

Cyclosporin (CsA) has powerful immunosuppressive properties, and its recent application to organ transplantation has resulted in markedly improved graft survival. However, CsA has certain adverse side effects, the most notable being nephrotoxicity and hepatotoxicity. Among other untoward effects, little is known about the effects of CsA on the reproductive organs. Since good graft survival is now expected with CsA, the long term effect of the drug on the gonads should be monitored carefully, particularly for young recipients. Prior to investigation of the effect of CsA on the testis, the level of CsA in semen of the adult renal transplant patients were measured. Twelve samples of semen from eight recipients, mean age 35 (SD 9), were collected by masturbation in the morning just before taking CsA after more than 5 day abstinence, and it was frozen at -80 degrees C. They had been taking immunosuppressants that were a combination of either CsA and prednisolone, or CsA, azathioprine and prednisolone for 5 to 63 months. The dose of CsA was 3.7 mg/kg to 5.0 mg/kg. The range of the level of serum creatinine was 1.1 mg/dl to 2.9 mg/dl. CsA in whole blood was measured by high performance liquid chromatography (HPLC), and CsA in semen was also measured by HPLC after extracting CsA with diethylether. The level of CsA in semen was 27 ng/ml to 165 ng/ml and that in whole blood was 51 ng/ml to 133 ng/ml. The relation between both levels was linear (r = 0.68, p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

[Diagnosis of the upper urothelial tumor using a rigid ureteroscope].

We preoperatively diagnosed four cases suspected as malignant urothelial tumor of upper urinary tract using a rigid ureteroscope. In three cases of ureter tumor, biopsy was successful and showed low grade malignancy. Nephroureterectomy was performed in two cases with upper ureteral tumor. The tumor was fulgurated ureteroscopically in a case of lower ureteral tumor. In one case of renal pelvic tumor, biopsy was unsuccessful though the tumor was observed as a papillary configuration. Successively, biopsy using a flexible ureteroscope was performed and the tumor was treated by fulguration. Ureteroscopy is very useful for preoperative diagnosis of ureteral tumor and selection of treatment.

Carcinoma, Transitional Cell↗
PubMed1989

Transient carnitine-responsive medium-chain dicarboxylic aciduria in an infant with cholestasis, hypoglycemia and cardiac failure.

In a cholestatic infant showing hypoglycemia and cardiac failure, non-ketotic medium-chain dicarboxylic aciduria was disclosed by urinary organic acid analysis. As urinary excretion of long-chain fatty acids was also increased, a defect in beta-oxidation of long-chain fatty acids appeared likely. To try to improve this abnormality, carnitine supplements were given, which led to the complete resolution of clinical and laboratory abnormalities. This is the first reported case of a cholestatic infant who responded to carnitine supplementation. Deficiency of carnitine palmitoyl transferase was suspected as the underlying cause.

Carnitine↗