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Biomedical subjects

I Takai

Publications and source records attributed to I Takai.

49 records · Page 3Linked to original sources
PubMed1982

[A progesterone-dependent step in HCG-induced ovulation in immature rats (author's transl)].

The effect of antiserum to progesterone on follicular rupture during the ovulatory process was studied. Mean number of ova shed following treatment of immature rats sequentially with PMS and hCG was reduced in a dose-dependent manner by simultaneous injection with increasing doses of antiserum to progesterone. When the animal received 1.2 ml of the antiserum, hCG-induced ovulation was blocked completely. To be effective, antiserum treatment had to be within 6 h of hCG treatment; antiserum given 9 h after hCG was ineffective. Progesterone restored' the antiserum blocked ovulation completely or incompletely when administered intravenously within 6 h of treatment with hCG. The first 6 h was shown to be a progesterone-dependent step in the ovulatory process in this experimental system.

Animals↗
PubMed1981

Use of chromogenic substrate S-2251 for determination of plasminogen activator in rat ovaries.

A simple specific and reproducible method for determination of plasminogen activator activity in rat ovaries has been developed by using the chromogenic substrate S-2251. The two steps of enzymatic reactions, i.e. activation of plasminogen and subsequent hydrolysis of the substrate was performed in one step incubation. A linear relationship was observed between the amount of chromogen produced and activator activity in the range of the optical density form 0.05 to 1.20 for 30 min's incubation. Endogenous activity of non-specific proteases, plasmin or plasmin inhibitors which might be contained in rat ovaries turned out not to interfere with the specificity of a standardized assay procedure. Reproducibility was firmly established with coefficient of variation not exceeding 10%. Using this method, a marked increase followed by a drastic decrease in the activator activity was shown with rat ovaries around the time of ovulation after the injection of human chorionic gonadotropin.

Animals↗
PubMed1981

A new method for preparation of pure zonae pellucidae in large quantities from porcine ovaries.

A new method for preparation of large quantities of zona substance in pure form from porcine ovaries has been described. In addition to the previously reported techniques of glass wool treatment and sieving by saran meshes, the following three significant improvements have been introduced: disruption of ovaries by an electric machine equipped with two multi-needed disks, which resulted in a considerably accelerated recovery of follicular oocytes with a high yield; low-speed centrifugation at 170 X g for 15 s was found to be an obligatory step to eliminate light particulate material from the crude oocyte suspension; use of 50% sucrose solution in discontinuous density gradient centrifugation permitted complete separation of homogeneous samples at two stages of the final preparation of zona-encased oocytes or of oocyte-free zonae. Microscopic examination revealed no contaminating components in the zona preparation. With this method 93 mg of lyophilized zona preparation were obtained from 24 553 porcine ovaries. Analysis of a solubilized zona substance by Sephacryl S-200 column chromatography showed the presence of two major glycoproteins which could not be separated completely from each other. By analysis of the two components with SDS-PAGE, only a single, but broad, band of glycoprotein was found, indicating the successful isolation of a major component(s) from porcine zonae.

Animals↗
PubMed1981

Heteroimmunization with isolated human ova.

Rabbit antiserum raised against isolated human ova produced an intense immunofluorescence and a precipitate on the outer surface of human and porcine zonae pellucidae. The antiserum reacted with none of 22 human tissues nor with any of 4 body fluid components by immunofluorescence or immunodiffusion analysis, but the antiserum agglutinated AB erythrocytes after absorption with O erythrocytes. The anti-zona activity was achieved by higher titres for human than for porcine zonae. Immunofluorescence on porcine zonae was completely abolished by absorption with porcine ova, whereas a weak but definite fluorescence remained on human zonae. These findings indicate that the human zona pellucida consists of at least three distinct components; (1) a specific antigen(s) shared by human and porcine zonae, (2) an antigen(s) specific to human zonae, and (3) a non-specific antigen(s) associated with the blood group substances.

Adult↗
PubMed1979

A method for specific detection of autoantibodies to the zona pellucida in infertile women.

Human antibodies to porcine erythrocytes were found to bind to porcine but not to human zonae pellucidae, whereas human isohemagglutinins bound to human but not to porcine zonae. On the basis of the binding behavior of agglutinins, it was found that the immunofluorescence of porcine zonae produced by selected sera from infertile women was due to an antibody of different specifity from that which agglutinated pig red blood cells. However, no serum component other than heteroagglutinin was contained in selected sera from control subjects which fluoresced porcine zonae. Since the component was present in the immunoglobulin G fraction, bound to human zonae, and was reactive with zona-specific antigen(s), it was judged an autoantibody to zonae. Thus a method for specific detection of autoantibodies to zonae has been developed by indirect membrane immunofluorescence using porcine ova as targets.

Absorption↗
PubMedDate not supplied

Mechanism of dialysis-induced hypotension.

Using a hematocrit monitoring system and a Swan-Ganz catheter, the authors investigated the changes in blood volume and hemodynamic parameters before, during, and after dialysis-induced hypotension. When hypotension occurred, the cardiac output dropped sharply, and there were concomitant sudden decreases in the mean pulmonary arterial pressure and the mean right atrial pressure. These are attributed to a decrease in venous return. Since there was no recognizable change in blood volume when the blood pressure fell sharply, decrease in the venous return is considered to be caused by relocation of circulating blood, possibly associated with a sudden decrease in venous tone.

Hemodynamics↗
PubMedDate not supplied

Relationship between dialysis induced hypotension and adenosine released by ischemic tissue.

Two types of dialysis induced hypotension apparently exist. One type presents as gradually decreasing blood pressure with eventual symptoms (gradual hypotension), whereas the other presents as abruptly and sharply decreasing blood pressure, along with symptoms (abrupt hypotension). In the current study, the authors found that the plasma hypoxanthine concentration during abrupt hypotension was significantly higher than before the hypotension occurred (20 min after saline was administered or at the beginning of dialysis), whereas comparison of the plasma hypoxanthine concentration during gradual hypotension and that before the hypotension occurred (20 min after saline was administered or at the beginning of dialysis) revealed no significant difference. The current results indicate that abnormally increased adenosine triphosphate (ATP) degradation associated with tissue ischemia occurred during abrupt hypotension but not during gradual hypotension. It can be speculated that the increased release of adenosine due to abnormally increased ATP degradation caused the abrupt hypotension. This conclusion seems reasonable given that adenosine directly decreases small vessel tone and inhibits prejunctional release of norepinephrine.

Adenosine↗
PubMedDate not supplied

Effects of anti-swine zona serum on swine and murine in vitro fertilization.

No investigations have been reported concerning the action of anti-swine zona (anti-SZ) antibodies in a swine in vitro fertilization (IVF) system. We examined the effects of anti-SZ on homologous swine IVF and heterologous murine IVF. Swine IVF and sperm-zona binding were inhibited after treating swine ova with 2(2) and 2(1) dilutions of antiserum, producing fertility rates of 25.9% and 1.6% respectively, which are significantly lower than the control group fertility rate of about 70%. However, the murine ova could accept the capacitated homologous sperm, even after treatment with the antiserum-derived IgG, which had an antibody titer twice that of the starting antiserum. The antiserum-reacted swine ova exhibited a zona precipitate and a concentration-dependent resistance to pronase and required about 17 minutes to disappear after reacting with the starting antiserum, whereas the antiserum-reacted murine ova, which did not exhibit a zona precipitate, and the control ova disappeared within three minutes. These results indicate that antibody deposition on the zona greatly affects the degree of fertilization inhibition. The immunogens used were characterized zona constituent glycoproteins, and the antiserum raised against them was previously proven to be highly specific. Therefore, we believe that a basis has been established for analyzing the fertilization phenomena that take place at the zona using swine systems.

Animals↗
PubMedDate not supplied

A new treatment strategy using both intermittent short dialysis and continuous ambulatory hemofiltration.

The authors devised a new treatment strategy using continuous ambulatory hemofiltration (CAHF) in between short hemodialyses (short HD). For CAHF, a small wearable hemofilter (0.1 m2) was developed using a membrane permeable to low molecular weight proteins. During short HD, no body water was removed, but saline, equivalent to 3% body weight, was administered at a constant rate. During CAHF, 1 L of replacement fluid was administered intravenously after every meal to increase the replacement volume. Switch from the conventional to new strategy resulted in far more stable blood pressure during short HD, a decrease in time averaged body weight, and a decrease in a decrease in time averaged blood urea nitrogen and plasma beta 2-m levels.

Ambulatory Care↗
PubMedDate not supplied

Tissue specificity and species cross-reactivity of porcine zona antigens isolated by gel filtration.

Antisera raised against two different doses of a major component of porcine zona pellucida isolated by gel filtration formed two precipitin lines with the components in agar double-diffusion gel. The antisera produced a positive immunofluorescence on the zona pellucida in sections of ovaries of pig, human, baboon, cow, sheep, rabbit, rat, mouse, hamster, and guinea pig. The antisera did not react with 58 different porcine tissues or five body fluids by immunofluorescence or immunodiffusion. No changes were observed in the fluorescence on the zona or in the precipitin lines when the antisera were previously absorbed with liver, erythrocytes, or plasma; however, after absorption with the porcine zona component both fluorescence and precipitin lines were completely abolished. Furthermore, control antisera against porcine erythrocyte ghosts and follicular fluid did not develop any immunofluorescence on the porcine zona. Both antisera to PZ-alpha and PZ-beta obtained by use of preparative SDS-PAGE developed the same immunofluorescence on the porcine zona shown by the antiserum to the zona component. These findings indicate that the major component of the porcine zona contains at least two zona-specific antigens, which have cross-reactivity with zona antigens of several other mammals, including humans.

Animals↗
PubMedDate not supplied

Relationship of protein catabolic rate or Kt/V with morbidity.

The authors investigated the influence of Kt/V and protein catabolic rate (PCR) on dialysis failure for 689 hemodialysis (HD) outpatients treated at the seven dialysis facilities in Aichi Prefecture, Japan. Dialysis failure was defined as death or hospitalization for reasons other than blood access, accident, wound, or mental disease. Patients were followed for 2 years. The rate of patients who developed dialysis failure during the observation period relative to the total patient population was defined as the dialysis failure rate. A total of 123 patients developed dialysis failure, which was fatal in 33 cases. In patients with Kt/V values of 1.6 or higher, the mean dialysis failure rate was significantly lower at 12.0% than that (19.2%) of patients with Kt/V values between 0.8 and 1.6 (p < 0.04). In patients that had PCR values under 0.8 g/kg/day, the dialysis failure rate was significantly higher at 32.5% than that (15.8%) of patients with PCR values between 0.8 and 1.4 g/kg/day (p < 0.0001).

Adult↗
PubMedDate not supplied

A new wearable system for continuous monitoring of arteriovenous fistulae.

A wearable system to constantly monitor the bruit generated by an AV fistula at times other than during dialysis was developed, and provided early detection of rapidly developing thrombi that cause occlusion of the fistular vessels. The system consists of a downsized microphone that continuously monitors the bruit generated, a warning device worn like a wristwatch, and a wire running down from the microphone to the emergency warning device. The microphone converts the bruit into an electrical signal and outputs it to the warning device. The emergency warning is then sounded whenever the input signal from the tiny microphone is weaker than a preset level. The warning device was set off in 4 of 21 long-term dialysis patients with arteriovenous fistulas, and within several hours all 4 developed an occlusion. One of the 14 patients with a graft had the device go off while sleeping, but it was a false alarm due to positioning that resulted in compression of the fistula arm.

Aged↗