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Biomedical subjects

Y Sakamoto

Publications and source records attributed to Y Sakamoto.

At least 631 records · Page 35Linked to original sources
PubMed1985

The mechanism of Ptychodiscus brevis toxin-induced rat vas deferens contraction.

Ptychodiscus brevis, which causes Florida red tide, produces Ptychodiscus brevis toxin (PBTX) known to contain neurotoxins and to induce rhinorrhea, tearing, and cough in normal humans and wheezing in asthmatic subjects. It was previously reported (J Allergy Clin Immunol 69:418, 1982; 73:824, 1984) that PBTX causes canine tracheal smooth muscle contraction via stimulation of sodium channels in the axons of parasympathetic postganglionic nerves and the release of acetylcholine from these nerve endings. This was postulated to be an asthma-triggering mechanism. In this article the toxins were evaluated to determine if they also stimulate sodium channels on adrenergic nerve endings and release norepinephrine. Rat vas deferens was selected as the experimental tissue. Both PBTX and norepinephrine contracted rat vas deferens. Prazosin 10(-6) mol/L blocked the response to PBTX (3 micrograms/ml) (88.3% to 27.3% contraction [n = 6; p less than 0.001]) and the response to norepinephrine (EC50 was shifted from 1.67 X 10(-6) mol/L to 1.25 X 10(-4) mol/L in the presence of prazosin 10(-6) mol/L [n = 6; p less than 0.001]). Phentolamine 10(-6) mol/L also blocked both PBTX and norepinephrine. Tetrodotoxin 10(-7) mol/L, a sodium channel blocker, completely blocked the response to PBTX but not to norepinephrine. The response to PBTX was significantly reduced from 1.53 gm of tension in controls to 0.29 gm of tension (n = 6; p = 0.002) in tissues obtained from rats pretreated with reserpine (2 mg/kg per day for 2 days, injected intraperitoneally). Verapamil 10(-5) mol/L blocked the PBTX response, and PBTX caused no contraction in calcium-free media.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

Lung hemorrhagic toxicity of butylated hydroxyanisole in the rat.

Male Sprague-Dawley rats were injected intraperitoneally (i.p.) with butylated hydroxyanisole (BHA) at doses of 0, 1, 4, 16, 64, 256, 384, 576, 864, 1296 and 1944 mg/kg/day for 7 days. Deaths occurred in a dose- and time-dependent manner when BHA was given in amounts greater than 576 mg/kg. The LD50 was 881 (484-1440) mg/kg. Intracranial hemorrhage was found in the dead rats, and lung hemorrhage was observed in the survivors given BHA at doses greater than 384 mg/kg/day. Histopathologically, intra-alveolar hemorrhages, thickening of alveoli and deposition of lipids in the lungs were observed. The prothrombin index was decreased only in rats given BHA at a level of 384 mg/kg/day. These observations suggest that BHA and/or its metabolite cause pulmonary hemorrhagic damage in rats. The mechanism of hemorrhage may be different from that of bleeding induced by butylated hydroxytoluene.

Animals↗
PubMed1985

A comparison of serum C-peptide response to intravenous glucagon, and urine C-peptide, as indexes of insulin dependence.

Serum C-peptide (SCPR) at fasting and after intravenous injection of glucagon was evaluated in diabetic patients with various degrees of insulin dependence, and compared with 24 h urine C-peptide (UCPR). Fasting SCPR did not differ between healthy subjects and sulfonylurea-treated patients (SU) who were considered to have definite non-insulin-dependent diabetes (NIDDM); but was significantly lower in patients with insulin-dependent diabetes (IDDM) (0.24 +/- 0.10 ng/ml in IDDM vs. 1.43 +/- 0.61 ng/ml in SU, P less than 0.001). SCPR reached a peak at 6 min after glucagon injection, except for the IDDM group. The SCPR response at 6 min after 1 mg glucagon injection was significantly lower in the SU (NIDDM) group than in the normal group (2.86 +/- 1.21 v. 4.69 +/- 1.47 ng/ml, P less than 0.001). In the IDDM group, there was no increase of SCPR after glucagon injection. Among diabetic patients, SCPR response to glucagon correlated positively to the amounts of UCPR (P less than 0.001). By analysis of the distribution patterns of SCPR response to intravenous glucagon, SCPR of 1.0 ng/ml and the increment of SCPR of 0.5 ng/ml at 6 min are to be used as cut-off points to differentiate IDDM and NIDDM. These values correspond roughly to the UCPR values below 20 micrograms/day and above 30 micrograms/day, which we previously proposed as indexes to differentiate insulin-dependent and non-insulin-dependent diabetes.

C-Peptide↗
PubMed1985

Re-evaluation of protein-bound glutathione in rat liver.

The extent of intracellular glutathione binding to proteins through a disulfide linkage in rat liver was examined quantitatively. The content of glutathione associated with the acid-precipitable fraction and releasable on borohydride treatment was 0.024 +/- 0.016 mumol/g liver, which accounted for less than one per cent of the total glutathione (6-7 mumol/g liver) in the liver of fed rats. Most of the thiol (2-4 mumol/g liver) liberated from liver proteins into the acid-soluble fraction on borohydride reduction in the presence of guanidine hydrochloride was not glutathione but was proteinaceous in nature. The amounts of thiols liberated per g of liver were similar in fed, fasted, and dibutyryl-3',5'-cyclic AMP-treated rats.

Animals↗
PubMed1985

Chromosome heteromorphisms and paternity testing.

Most of the blood group systems have now been applied to paternity investigations. In a complicated case, an alleged father not excluded with blood group testing, could be excluded with only chromosome heteromorphisms. Chromosome heteromorphisms are inherited from parents to offspring as simple Mendelian laws. The authors' paternity testing is presented with the help of chromosome heteromorphism analysis.

Blood Grouping and Crossmatching↗
PubMed1985

In vivo color analysis of human crystalline lenses.

Indirect measurement in vivo of nuclear color of 64 cataractous eyes was made using a method of image analysis of photographed lenses developed by the authors. The grade of yellow of lens color was characterized by its dominant wavelength and excitation purity in the CIE chromaticity diagram. The differences were small between nuclear color observed from in vivo and in vitro photographs.

Adult↗
PubMed1985

The effect of Mn on the electrical and mechanical activities in the guinea-pig stomach.

The effects of Mn on electrical and mechanical activities in the circular muscle of the guinea-pig stomach were investigated. A low concentration of Mn (0.1 mM) in Krebs solution caused a prolongation of the first component, resulting in an increase in frequency of the second component. However, a high concentration of Mn (more than 1 mM) had a similar effect on the electrical activities in the early period, but subsequently inhibited them. The membrane was depolarized by Mn from 69 (S.D., +/- 6) to 63 (S.D., +/- 6) mV at 0.1 mM and to 42 (S.D., +/- 5) mV at 2 mM in the Krebs solution. The membrane resistance slightly decreased with 0.1 mM Mn, but slightly increased with 2 mM Mn. A low concentration of Mn (0.1 mM) also increased resting tone and phasic contraction. These contractile responses were completely inhibited when Ca was removed from the bathing solution. The enhanced, later phasic contraction was reduced by verapamil. All these electrical and mechanical responses for Mn were not related to the nervous system. Excess Ca (15 mM) inhibited the actions of Mn on the spontaneous slow waves, the resting potential, and the duration of the second component. Thus, it is concluded that Mn displaces or releases Ca from its stored sites, which are loosely-bound pools, and then induces membrane depolarization, resulting in subsequent stimulation of the Ca-channel, which is blocked by a high concentration of Mn.

Animals↗
PubMed1985

Shift of circadian metabolic rhythm in BFO osteosarcoma-bearing mice.

The diurnal rhythms of the contents of serum corticosterone and liver glycogen and the activity of liver tyrosine aminotransferase gradually shifted forward in C3H/He mice bearing BFO osteosarcoma. The production of alkaline phosphatase by the tumor showed a circadian rhythm. The eating behavior of tumor-bearing mice seemed to be responsible for their change in circadian rhythm.

Alkaline Phosphatase↗
PubMed1985

[A clinico-pathological implication of ABO (H) blood group substances expressed in the primary lesion of uterine cervical carcinoma].

The disappearance of ABO(H) blood group antigens seen in the lesions of carcinoma of the uterine cervix has been studied by the Avidin-Biotin-Complex (ABC) method and the results have been correlated with histology and prognosis. The incidence of cases showing complete loss of A or B antigens was increased with progression in the pathological picture of cancer, whereas H antigen, known as precursor carbohydrate chains of A and B antigens, was still sustained even in most cases of invasive cancer. In the tissue of invasive cancer, the complete loss of H antigen was easily able to be demonstrated in the small cell non-keratinizing type of carcinoma, but it is hardly able to be seen in the large cell non-keratinizing type and not demonstrated in the keratinizing type of carcinoma. Though no relationship was recognized between the disappearance of A, B or H antigens and parametrial spread of carcinoma or metastasis to the pelvic lymphnodes, the incidence of patients who died within two years after operation was apparently higher in the H antigen negative group than in the H antigen positive group. It is concluded that the disappearance of A or B antigen may correlate with the invasiveness of the cancerous lesion, while that of the H antigen may reflect the grade of dedifferentiation of the neoplasia with the implication of an unfavorable prognosis.

ABO Blood-Group System↗
PubMed1985

Allergenicity and immunogenicity of house-dust mite (Dermatophagoides farinae) antigens treated with glutaraldehyde.

Extract from house dust mite (Dermatophagoides farinae) was treated with glutaraldehyde (GA) and examined for its allergenicity and immunogenicity. The allergenicity of glutaraldehyde-treated mite extract (GA-M) was decreased significantly when compared with untreated mite extract (UN-M) by skin test in mite allergic individuals. Immunogenicity of GA-M was at least similar with that of UN-M, when examined by formation of antibodies to UN-M in guinea pigs. Fractionations of GA-M and UN-M revealed that polymerization occurred and proteins of higher molecular weight increased after the treatment of mite extract with GA. The results suggest potential usefulness of the polymerized mite antigens in immunotherapy.

Aldehydes↗