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Biomedical subjects

Y Katoh

Publications and source records attributed to Y Katoh.

At least 199 records · Page 11Linked to original sources

Changes of molecular forms of atrial natriuretic peptide after treatment for congestive heart failure.

In the present study, an attempt was made to clarify whether ANP molecular forms in the plasma of severe congestive heart failure patients differ from those in healthy persons and whether ANP molecular forms in the plasma of the patients were changed by successful treatment of cardiac disease. Twenty patients with congestive heart failure were treated at Kitasato University Hospital. They were classified as class III or IV by New York Heart Association criteria at the time of admission. Plasma ANP concentrations decreased after treatment from 356 +/- 58.2 to 72.3 +/- 14.8 pg/ml. The gel permeation chromatograms from the plasma of healthy persons showed low, or low and high molecular weight ANP peaks which correspond to the elution positions of authentic alpha-ANP or ribonuclease A (mol. wt., 13.7 kdalton). In patients with severe congestive heart failure at a severe stage, middle molecular weight ANP consisted with the elution position of authentic beta-ANP was particularly noted in addition of low and high molecular weight ANP peaks. This middle molecular weight peak disappears in most of cases by successful treatment. Molecular forms in the plasma obtained from the coronary sinus and the inferior or superior vena cava were essentially the same. These results indicate that the middle molecular weight ANP supposed as beta-ANP may particularly be secreted in severe congestive heart failure patients.

Adult↗

Promotive effect of 4,4'-methylenebis(N,N-dimethyl)benzenamine on N-bis(2-hydroxypropyl)nitrosamine-induced thyroid tumors in Wistar rats.

The promotive effect of 4,4'-methylenebis(N,N-dimethyl)benzenamine (MDBA) on 2-stage thyroid tumorigenesis induced by N-bis(2-hydroxypropyl)nitrosamine (DHPN) in Wistar male rats was investigated. Animals were given i.p. injections of DHPN, and then a basal diet containing 0.0375% MDBA for 19 weeks. In addition, localization of the thyroid-stimulating hormone (TSH) in the pituitary gland was investigated. Levels of TSH and T4 in serum were measured by radioimmunoassay (RIA). The addition of MDBA to the diet significantly increased the incidence and numbers of preneoplastic lesion (focal hyperplasia), adenoma and carcinoma of the thyroid. TSH was usually localized in the thyroidectomy-cell in the anterior lobe of the pituitary gland, and the number of TSH-positive cells increased in the group treated with MDBA. Mean circulating levels of TSH were elevated in all MDBA-treated groups, and mean T4 levels in groups treated with MDBA were significantly lower different (P less than 0.05) than those in control groups.

Aniline Compounds↗

Both B151-T cell replacing factor 1 and IL-5 regulate Ig secretion and IL-2 receptor expression on a cloned B lymphoma line.

In the present study, we have demonstrated that both B151-T cell-replacing factor 1 and rIL-5 are responsible for the activity to partially induce CL-3 cells into IgM-synthesizing cells and also to synergize with IL-2 to augment IL-2R expression on and IgM synthesis in CL-3 cells. These actions of rIL-5 on a homogeneous cloned line (BCL1-CL-3 cells) allow us to identify and characterize the two alternated B cell developmental pathways. One is an IL-2-independent, IL-5-driven differentiation pathway without preceding up-regulated IL-2R expression, and the other is an IL-5 plus IL-2-dependent augmented differentiation pathway with preceding up-regulated IL-2R expression. We have also demonstrated the functional difference of two distinct B cell growth-promoting factors, B cell-stimulating factor 1 (rIL-4) and rIL-5. CL-3 cells are equally stimulated to grow by rIL-4 and rIL-5, whereas only rIL-5 can render CL-3 cells responsive to rIL-2, indicating that these two lymphokines affect B cells in a strikingly different manner.

Animals↗

Induction of achromosomal cleavage by hydroxyurea in starfish embryo and the reversal by a combination of deoxyadenosine and deoxycytidine: possible involvement of salvage pathway for deoxynucleoside triphosphate biosynthesis in the presence of hydroxyurea.

Effects of hydroxyurea, an inhibitor of ribonucleotide reductase, on cleavage of starfish embryos were studied. In the presence of 1 mM hydroxyurea, fertilized eggs of the starfish, Asterina pectinifera, cleaved up to the 256-cell stage and decomposed before blastulation. Before the 16-cell stage, each blastomere contained a normal nucleus or chromosomes with mitotic apparatus. The cleavage after the 16-cell stage was slow compared to the control embryos, and not all blastomeres contained a nucleus or normal chromosomes. During the fifth cell division (between 16-cell- and 32-cell-stage embryos), chromatin mass unassociated with the mitotic apparatus remained near the cleavage furrow. When hydroxyurea was removed before the 16-cell stage, the embryos developed to normal bipinnalia larvae via normal blastulae. However, the embryos were disintegrated before blastulation when hydroxyurea was removed after the 32-cell stage. DNA synthesis was normally observed before the 16-cell stage but not after the 16-cell stage, but dNTP contents in the embryos remained low throughout development in the presence of hydroxyurea. The achromosomal cleavage observed in the presence of hydroxyurea was reversed by the combination of extracellular dAR and dCR. Therefore, it is assumed that the synthesis of dNTPs required for DNA synthesis in the presence of hydroxyurea occurs via the salvage pathway using deoxynucleosides (dNR) (dNR to dNTP via dNMP and dNDP).

Animals↗

Atrial natriuretic peptide is only a minor diuretic factor in dehydrated subjects immersed to the neck in water.

To determine if the atrial natriuretic peptide (ANP) is an important factor for inducing diuresis during head-out water immersion even in dehydrated subjects, six healthy volunteers were immersed up to the neck in water at 34.5 degrees C for three hrs. Significant diuresis and natriuresis occurred, but urine osmolality decreased and negative CH2O was restored in a positive direction toward zero, even though subjects were still in a state of considerable dehydration. Plasma renin activity and plasma angiotensin I and II concentrations decreased but that of plasma aldosterone remained unchanged during water immersion, and plasma ANP did not increase throughout the examination. On the basis of the data of the present study, the factor inducing diuresis during head-out water immersion in hydrated subjects appears to differ from that in dehydrated subjects, and the main factor inducing diuresis during water immersion in dehydrated subjects may be the suppression of vasopressin release and not ANP.

Adult↗

Noninvasive evaluation of the ratio of pulmonary to systemic flow in ventricular septal defect by means of Doppler two-dimensional echocardiography.

Left ventricular inflow volume (LVIV) and outflow volume (LVOV) were determined by pulsed Doppler echocardiography, and the ratio of pulmonary to systemic flow (Qp/Qs) was estimated as a ratio of LVIV to LVOV (LVIV/LVOV). Seventy-seven patients were studied, 47 control subjects and 30 patients with ventricular septal defect (VSD). LVOV was calculated from the left ventricular ejection flow velocity and left ventricular outflow tract diameter; LVIV was calculated from the transmitral flow velocity and mitral valve motion as traced by M-mode echocardiography. Cardiac input (COin) and cardiac output (COout) were calculated as the product of LVIV or LVOV and heart rate. Cardiac output was also determined by the dye dilution method (COdye) in control subjects. A close correlation was observed between COdye and COin (y = 1.18x - 243, r = 0.85, p less than 0.005, SEE = 1026 ml/min) and COdye and COout (y = 1.16x - 323, r = 0.90, p less than 0.005, SEE = 639 ml/min). LVIV and LVOV were highly correlated in control subjects (y = 0.95x + 5.3, r = 0.94, p less than 0.005, SEE = 6.6 ml). LVIV/LVOV was 0.97 +/- 0.1 (mean +/- SD) in control subjects, whereas LVIV/LVOV (1.87 +/- 0.88) was significantly higher in patients with VSD (p less than 0.01). In patients with VSD, LVIV/LVOV correlated with Qp/Qs determined invasively (y = 0.97, SEE = 0.23, n = 16). Thus with our method LVIV and COin can be accurately determined, and we suggest that Doppler-determined LVIV/LVOV is clinically useful for evaluating the shunt flow magnitude in VSD.

Adult↗

Production of normal piglets from microsurgically split morulae and blastocysts.

The embryo splitting technique was applied to pig embryos, and the developmental ability of the split embryos was examined by means of in vitro culture and transfer. Morulae, early blastocysts and blastocysts were collected from Landrace x Large White F(1) gilts which had been mated to Duroc boars. The embryos were bisected with a fine glass or alloy (PtIr) needle after the softening of zonae pellucidae. The halved-embryos, which had either been placed in zonae pellucidae or not, were transferred to recipient gilts immediately after the micromanipulation (Experiment 1) or after cultivation for 15 to 20 h (Experiment 2). In Experiment 1, two fetuses were obtained from one of three recipients which had received 12 half-embryos. In Experiment 2, three of five recipients became pregnant, and in one recipient, seven piglets of a litter were obtained from 12 zona-free half-embryos produced from the original seven blastocysts. The results obtained indicate that a simple method not requiring the encasing of split embryos into zonae pellucidae is satisfactory to produce viable half-embryos.

Journal Article↗

Occipito-cervical fusion reinforced by Luque's segmental spinal instrumentation for rheumatoid diseases.

Thirteen rheumatoid patients who suffered from severe neck-occipital pain with or without myelopathy due to cranio-cervical instability, were operated on using a modified U-shaped rod. Twelve of them concomitantly had lower cervical rheumatoid lesions. Average extent of fusion was 5.9 levels. Bone union was confirmed in twelve cases in which autogenous bone graft had been used at approximately 4 months postoperatively; methylmethacrylate was used in the remaining one case. Good alignment of the cervical spine also was obtained in 12 cases; one patient experienced occipito-C2 shortening after an additional surgery for deep infection. Improvement of neck-occipital pain was noted in all cases, and seven of eight patients with myelopathy showed neurologic recovery.

Arthritis, Rheumatoid↗

[Study on producing rats with experimental testicular dysfunction and effects of mecobalamin].

Experiments were performed to investigate the effects of mecobalamin (CH3-B12) on disorders of testicular function. Male rats received subcutaneously an injection of doxorubicin (ADR) three times a week for 3, 5 and 7 weeks. Thereafter, they were periodically sacrificed for the examination of cauda epididymal sperm profiles and the morphology of the testis. ADR treatment caused a decrease in sperm counts, sperm motility and the diameter of the seminiferous tubules, and an increase in the percentage of abnormal sperms. These damaging effects depended on the dosage and period of treatment with ADR. Based on these findings, rats with testicular dysfunction induced by the treatment with ADR at a daily dose of 0.25 mg/kg, three times a week for 5 weeks were prepared to investigate the effects of CH3-B12 on oligozoospermia. CH3-B12 was given intraperitoneally to the oligozoospermic rats six times a week for 5 and 10 weeks. The results obtained indicated that 1,000 micrograms/kg of CH3-B12 caused a significant increase in both the sperm counts and the diameter of the seminiferous tubules. These results suggest that CH3-B12 is a candidate drug for oligozoospermia.

Animals↗

A case of cutaneous T cell lymphoma treated with recombinant interleukin 2 (rIL-2).

We report a case of cutaneous T cell lymphoma (CTCL) treated with local injection of recombinant interleukin 2 (rIL-2). The biopsy specimen showed marked infiltration of large convoluted cells admixed with small lymphocytes and histiocytes in the epidermis, dermis and subcutis. After six injections of rIL-2, 4 nodules out of 5 on the left lower leg disappeared and the remaining large nodule was diminished in size. A biopsy specimen from the diminished nodule showed infiltration of small lymphocytes with histiocytes and plasma cells in the dermis. The atypical cells, large hyperconvoluted lymphocytes, had disappeared. A large number (28%) of lysozyme- and alpha 1-anti-chymotrypsin-positive cells were demonstrated by immunohistochemistry. The patient maintained complete remission for a period of 13 months. He then noticed a small red nodule on the back of the left foot, which was histologically confirmed as a recurrence. Chemotherapy cleared the lesion.

Adult↗

[Pharmacokinetic study on oxalate in rats].

The pharmacokinetics of oxalate were studied in normal and nephrectomized rats, using radioisotope-labelled oxalate to resolve the mechanism of calcium oxalate stone formation. Plasma disappearance of 14C-oxalate was analyzed with a 2-compartment open model, and each compartment volume, the first-order rate constant for elimination, and the first-order rate constant for transfer between the central compartment and peripheral compartment were obtained. These values were compared with those for inulin. In normal rats, the total distribution volume was 57% of body weight for oxalate and 34% for inulin. The elimination rate constant from the central compartment for oxalate was lower than that for inulin, but oxalate had a much larger central compartment volume than inulin. Thus, the total clearance of oxalate was greater than that of inulin. In nephrectomized rats, total clearance of oxalate decreased to 1/6 of that in normal rats, while total clearance of inulin decreased to 1/27 of that in normal rats. These results suggest that oxalate is more diffusible than inulin, and that oxalate is excreted mainly from the kidney.

Animals↗