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Biomedical subjects

T Ichikawa

Publications and source records attributed to T Ichikawa.

At least 505 records · Page 28Linked to original sources
PubMed1988

In situ hybridization demonstrating coexpression of urotensins I, II-alpha, and II-gamma in the caudal neurosecretory neurons of the carp, Cyprinus carpio.

In order to examine the coexpression of different urotensins in the same caudal neurosecretory neurons, in situ hybridization with synthetic oligonucleotide probes specific for mRNAs for urotensins I, II-alpha, and II-gamma (UI, UII-alpha, and UII-gamma) was applied to the caudal neurosecretory system of the carp, Cyprinus carpio, together with immunohistochemistry. Almost all identifiable caudal neurosecretory neurons were labeled with the oligonucleotide and cDNA probes for UI mRNA. Further, any two of the probes for UI, UII-alpha, and UII-gamma mRNAs labeled the same neurons in serial sections. These results suggest that essentially all caudal neurosecretory neurons of the carp coexpress UI, UII-alpha, and UII-gamma. Although most neurons were densely labeled with oligonucleotide probes, only a small portion of the neurons were intensely immunoreactive. This suggests that most caudal neurosecretory neurons actively synthesize all three hormones, but that in some neurons, all or some of the hormones are rapidly transported to the urophysis, resulting in low or undetectable immunoreactivity in the perikarya.

Animals↗
PubMed1988

Changes of HDL subfraction concentration and particle size by intralipid in vivo.

The effects of the artificial triglyceride-phospholipid emulsion (10% intralipid) on HDL subfraction were studied in vivo. After a 14-h fast, subjects received intralipid via a 4-h infusion. Serum lipoproteins were analyzed before and at 4 and 6 h after the start of the infusion. At 4-h the following acute changes by infusion were observed. Triglyceride, phospholipid, free cholesterol, and esterified cholesterol in chylomicrons and VLDL increased. HDL2 as well as triglyceride, phospholipid, free cholesterol and protein within the HDL2 increased, while HDL3 decreased. An increase in HDL3 triglyceride was observed. The masses of apo A-I and A-II in the HDL2 density interval rose while these parameters fell in HDL3. There were decreases of apo C-II and C-III in the HDL subfractions and elevations in chylomicrons and VLDL. The particle size of the HDL subfractions increased. However, most of these acute changes at 4 h tended to disappear by 6 h. These results suggest that there is exchange of lipids and reversible transfer of apo C-II and C-III between HDL subfractions and intralipid, and conversion of HDL3 to HDL2 followed by the reverse conversion of HDL2 to HDL3 as the synthetic emulsion is cleared from the plasma.

Adult↗
PubMed1988

Effect of leuprolide on growth of rat prostatic tumor (R 3327) and weight of male accessory sex organs.

Leuprolide, a synthetic LHRH analog, inhibited growth of the Dunning R 3327 androgen-sensitive rat prostatic tumor and induced weight loss in male accessory sex organs. The relationship between the mode of administration and efficiency of the treatment was examined. Maintenance of the drug level in vivo seemed to be one of the important factors in the suppression of tumor growth, while a decrease in the weight of the accessory sex organs was mainly dependent on the dose administered. No treatment with leuprolide surpassed the effect caused by castration. Cytosolic androgen receptor and acid phosphatase activity in the tumor tissues were not changed significantly after treatment with leuprolide.

Acid Phosphatase↗
PubMed1988

Relationship between the occurrence of late potential on the body surface ECG and cardiac performance in myocardial infarction.

Comparative evaluations of the percent of the perimetric circumference of infarction and cardiac performance for the occurrence of late potential were performed in 12 normal subjects and 22 patients with old myocardial infarction (MI). All patients were in normal sinus rhythm without bundle branch block. Bipolar X, Y, and Z leads were signal-averaged using a bandpass filter with a low-cut frequency of 100 Hz and a high-cut frequency of 300 Hz. The filtered signals for the three leads were displayed and combined into a vector magnitude, square root of X2 + Y2 + Z2. The percent ratio of the root mean square voltage in the last 40 msec of the QRS complex was calculated against that of the total filtered QRS (%RMS40). The value of the standard deviation (SD) in the phase distribution was obtained by the Fourier analysis of multi-gated blood pool images. Significant differences were observed among MI with late potential, MI without it and the normal subjects for %RMS 40 (5.7 +- 2.8% vs 26.9 +- 8.1, 37.5 +- 10.8%). Left ventricular ejection fraction was lower in MI with late potential (19.7 +- 7%) compared to that of MI without it (33 +- 18%) and the normal subjects (60 +- 4%); the value of SD was higher in MI with late potential (64 +- 21 degrees), compared to that of MI without it (43 +- 20 degrees) and the normal subjects (9 +- 4 degrees). These findings showed that the percent ratio of the last 40 msec RMS voltage (%RMS 40) was found to discriminate effectively among MI with and without late potential and normal subjects. It was suggested that the amount and structure of the infarcts may be important factors in the occurrence of late potential.

Adult↗
PubMed1988

[Prostatic carcinoma. I: Androgen dependency of prostatic carcinoma].

Endocrine therapy, which consists of orchiectomy followed by administration of large doses of estrogen, then a reduced amount of estrogen, has been applied as the main treatment for stage D2 prostatic cancer. Alternatively, anti-androgen is used for elderly patients or those with cardiovascular disorders. Survival rate with endocrine therapy at 5 and 10 years was 35% and 16%, respectively. Therefore, in Japan, a better survival is shown than that reported in western countries using much smaller doses of estrogen. Most of the side effects caused by estrogen are not serious. Side effects caused by anti-androgen are few except for loss of libido. At the start of treatment, more than 80% of patients showed a response, but gradually relapse occurred and only 20% were well controlled 5 years after the start. Factors influencing the survival were pathological grade, response to endocrine therapy judged by the level of prostatic acid phosphatase 4 weeks after the start, and R1881 (methyltrienolone)-binding protein observed histochemically. The latter protein was also correlated with the grade and response to endocrine therapy. Relapse after endocrine therapy might be attributable to adaptation or mutation progressing to androgen-independent cells. Using SC 115, an androgen-dependent mouse tumor, these two types of relapse were demonstrated. Gradual progression to undifferentiated cancer was noticed between pretreatment biopsy and autopsy. Relapse in human prostatic cancer may thus be partly due to genetic change to a resistant clone.

Androgen Antagonists↗
PubMed1987

Monoclonal antibodies to monkey brain choline acetyltransferase: production and immunohistochemistry.

Two monoclonal antibodies to monkey brain choline acetyltransferase (ChAT) were obtained. Immunoblot analysis indicated that both antibodies revealed two adjacent protein bands on a sodium dodecyl sulfate-polyacrylamide gel electrophoresis. ChAT was demonstrated immunohistochemically by one of the antibodies in the motoneurons in the monkey brainstem and spinal cord. This antibody also revealed ChAT-positive terminal-like structures in the neuropils of lamina IX of the cervical spinal cord and interpeduncular nucleus.

Animals↗
PubMed1987

Effector cells in allelic H-2 class I-incompatible skin graft rejection.

The cellular mechanisms of skin graft rejection with allelic H-2 class I differences were studied by examining the effect on graft survival of in vivo administration of anti-Lyt-2.2 mAb, anti-L3T4 mAb, or both to recipient mice. The injections of anti-Lyt-2.2 mAb and anti-L3T4 mAb caused selective depletions of Lyt-2+ cells and L3T4+ cells, respectively. Injection of anti-Lyt-2.2 mAb significantly prolonged graft survival in 7 of 12 combinations of H-2D-end difference, but did not prolong graft survival in 5 other combinations of H-2D-end difference, or in 2 combinations of H-2K-end difference. Injection of anti-L3T4 mAb did not prolong graft survival in any combinations with class I difference tested. Injection of anti-L3T4 mAb plus anti-Lyt-2.2 mAb markedly prolonged graft survival in the combinations with class I difference in which anti-Lyt-2.2 mAb had no effect and overcame the effect of anti-Lyt-2.2 mAb in those in which anti-Lyt-2.2 mAb had an effect in prolonging graft survival. These results indicated that in combinations in which anti-Lyt-2.2 mAb did not prolong graft survival, class I antigen stimulated L3T4+ effector cells when Lyt-2+ cells were blocked and Lyt-2+ effector cells when L3T4+ cells were blocked. On the other hand, in the combinations in which anti-Lyt-2.2 mAb prolong graft survival, these antigens initially caused preferential stimulation of Lyt-2+ but not L3T4+ effector cells, although delayed activation of L3T4+ effector cells occurred when Lyt-2+ cells were blocked. Furthermore, a significant correlation was found between the effect of anti-Lyt-2.2 mAb in prolonging graft survival and the failure of recipient mice to produce H-2 antibody. These results can be taken as evidence that L3T4+ effector cells are not involved in the initial phase of graft rejection in these combinations.

Alleles↗
PubMed1987

Modalities of chemotherapy and endocrine therapy for growth inhibition of androgen-stimulated mouse carcinoma (Shionogi carcinoma 115).

Effects of chemotherapy and endocrine therapy applied individually or in combination on growth of an androgen-stimulated mouse tumor, Shionogi carcinoma 115 (SC 115), were examined. In the present study cyclophosphamide and castration were used as chemo- and endocrine therapy, respectively, and simultaneous combination of these two treatments was found to be the most effective in inhibiting tumor growth. When comparing the effect of castration alone with that of injection of cyclophosphamide alone, the former retarded the tumor growth more efficiently, but relapse occurred in both instances. Injection of cyclophosphamide to the relapsed tumor after castration caused a marked effect when compared with the effect of the drug on the untreated or the chemotherapy-relapsed tumors. Castration caused a retardation of growth in the chemotherapy-relapsed tumor, but the survival period was shorter than that observed in the mice that received castration followed by injection of cyclophosphamide. From these results, it was concluded that castration followed by chemotherapy was the preferred order among sequential treatments for the SC 115; however, the optimal treatment was produced by simultaneous combination of chemotherapy plus castration.

Androgens↗
PubMed1987

Monoclonal antibodies to hydroxyindole O-methyltransferase from bovine pineal gland.

Hybridomas that produce monoclonal antibodies to bovine hydroxyindole O-methyltransferase have been established by immunizing a mouse with hydroxyindole O-methyltransferase partially purified from bovine pineal glands followed by fusion of the spleen cells with myeloma NS-1 cells. Twenty-three clones have been isolated by screening the medium by two different methods. These clones produced various antibodies with different binding properties. Most of the antibodies belonged to IgG1 subtype, while 7 clones produced IgG2 alpha or IgG2 beta antibodies. Three antibodies inhibited enzymatic activity, whereas others did not. Antibodies of 7 clones recognized enzyme protein denatured with sodium dodecyl sulfate, while other antibodies reacted only with native enzyme protein. Thus a variety of monoclonal antibodies will offer us a good tool for immunohistochemical localization of the enzyme, immunoaffinity purification of hydroxyindole O-methyltransferase, and isolation of the cDNA clones encoding it. We also report here on the immunohistochemical demonstration of hydroxyindole O-methyltransferase in bovine pineal gland and a new immunoaffinity procedure to purify the enzyme to homogeneity by use of monoclonal antibodies.

Acetylserotonin O-Methyltransferase↗
PubMed1987

Prolonged survival of hamster-to-rat liver xenografts using splenectomy and cyclosporine administration.

The immunosuppressive effect of splenectomy, alone or in combination with cyclosporine (CsA), was examined in hamster-to-rat orthotopic liver xenografts. The mean survival time was 7.3 +/- 0.5 days in untreated controls, 7.6 +/- 0.8 days with 40 mg/kg/day CsA, 7.2 +/- 0.4 days with splenectomy alone, and 17.6 +/- 5.6 days with splenectomy combined with 30 mg/kg/day CsA (P less than 0.01). The longest survival time was 27 days in this group. Marked enlargement of the spleen and high lymphocytotoxic antibody titer were characteristic of the unmodified recipients and those treated with CsA alone. Splenectomy by itself decreased the antibody formation without improvement of graft survival. In animals treated with the combined regimen, the lymphocytotoxic antibody titer was significantly suppressed, and the PMN and round cell infiltration were greatly reduced. Therefore, a synergistic effect was postulated between cyclosporine and splenectomy in this liver xenograft system.

Animals↗
PubMed1987

A serological survey of simian virus 40 in monkeys.

A serological survey of simian virus 40 (SV 40) was conducted by an immune adherence hemagglutination (IAHA) test in breeding monkeys. Of a total of 356 monkeys tested, 168 (47.2%) were seropositive. All 168 seropositive monkeys were detected from 224 monkeys which were bred or kept in Japan for a long time. In contrast, none of the 132 monkeys which were newly imported from Southeast Asia was seropositive. If a comparison was made in the same breeding place, the positive rate of 80.4% (111/138) of Japanese monkeys was significantly (P less than 0.01) higher than the 59.5% (25/42) among rhesus monkeys. The positive rate and the IAHA titers were higher in older age group (greater than 5 years) but similar in male and female. These results indicated that SV 40 was highly prevalent among breeding monkeys in Japan.

Animals↗
PubMed1987

Monoclonal antibodies to and immunoaffinity purification of choline acetyltransferase from bovine brain.

Three hybridomas producing monoclonal antibodies to bovine brain choline acetyltransferase (ChAT) have been established by fusion of the spleen cells from a mouse immunized with purified enzyme with myeloma NS-1 cells. All three clones produced IgGl antibodies that reacted with enzyme protein denatured with sodium dodecyl sulfate. By using one of the monoclonal antibodies, a rapid and efficient immunoaffinity purification procedure of bovine ChAT has been established. Immunoblot analysis and immunoaffinity purification indicated that bovine ChAT is a single 68-kilodalton protein. The monoclonal antibodies will offer us a good tool to isolate the cDNA clones encoding ChAT.

Animals↗
PubMed1987

Incidence and clinical course of right ventricular infarction: assessment with radionuclide ventriculography.

The incidence and prognosis of right ventricular infarction were studied by radionuclide ventriculography (RNV) in 50 consecutive cases of acute myocardial infarction. RNV was performed within thirty-six hours of symptoms and one month after onset. Right ventricular infarction was absent in all 25 patients with anterior infarction. It was found in 15 of the 25 patients with inferior infarction, accompanied by a marked reduction in right ventricular ejection fraction (28 +/- 8%), but was notably alleviated one month later with normalization of right ventricular ejection fraction (39 +/- 7%) and wall motion. These phenomena seem to be specific in right ventricular infarction.

Adult↗