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Biomedical subjects

Y Shiojima

Publications and source records attributed to Y Shiojima.

At least 19 recordsLinked to original sources
PubMed1990

Performance of wide-pore silica- and polymer-based packing materials in polypeptide separation: effect of pore size and alkyl chain length.

The effects of pore size and alkyl chain length of silica- and polymer-based packing materials in the elution of polypeptides with an acetonitrile gradient in the presence of trifluoroacetic acid were studied. Considerable differences were found in the performance of alkylsilylated phases prepared from various wide-pore silica particles assumed to have 30-50-nm pores. The pore size of such silica gels was found to be the critical factor in determining the efficiency for high-molecular-weight polypeptides. Silica C18 phases having small pore volumes below 20 nm pore diameter showed comparable performances to C4 and C8 phases for polypeptides with molecular weights of up to 80,000, and were more stable. Polymer-based packing materials with adequate pore size provided excellent column efficiencies and recoveries for polypeptides with higher chemical stabilities than silica-based materials.

Acetonitriles↗
PubMed1986

Baroreflex participation of cardiovascular response to E. coli endotoxin.

The purpose of this experiment was to evaluate the effects of the arterial baroreceptor buffering capacity on cardiovascular parameters during hypotension caused by E. coli endotoxin in anesthetized dogs. In the control group, mean blood pressure and cardiac output fell significantly from 104 +/- 10 mmHg to 63 +/- 7 mmHg and 1.17 +/- 0.16 l/min to 0.67 +/- 0.08 l/min, respectively, 60 min after intravenous injection of endotoxin (1 mg/kg). Central venous pressure also decreased significantly after the injection. Total peripheral resistance and portal vein pressure increased significantly immediately after the injection, and then returned toward baseline levels. The time course of changes in these five cardiovascular parameters after the injection of endotoxin was the same as that in dogs with sino-aortic denervation. Following the injection of endotoxin, stroke volume and left ventricular dP/dt fell significantly in both control and denervated dogs; however, these decreases in the denervated group were significantly greater. These findings suggest that the arterial baroreceptors may play a role in the poor compensatory response to hypotension induced by endotoxin, at least, in the cases of mean blood pressure, cardiac output, total peripheral resistance, central venous pressure, and portal vein pressure.

Animals↗
PubMed1986

Reflex renal vasoconstriction on portal vein distension.

The present experiments were designed to study effects of neural control mechanisms on renal sympathetic nerve activity during acute portal vein distension in anesthetized dogs. Following the inflation of a balloon placed into the main portal vein of animals with the neuraxis intact (intact group), portal vein pressure at a site of the splanchnic regions increased significantly. Mean blood pressure (MBP) fell significantly and then renal vascular resistance (RVR) increased significantly in parallel with changes in portal venous pressure. In animals with sinoaortic denervation (SAD group), changes in portal venous pressure during the inflation of a balloon did not differ from the intact group. However, decreases in MBP in the SAD group were greater than that in the intact group, and sinoaortic denervation did not alter increases in RVR. In animals with both sinoaortic denervation and cervical vagotomy (vagotomy group), portal vein distension produced more profound hypotension, and significant increases in RVR occurred. This increase in RVR, however, was abolished by renal nerve denervation. The results of the present study indicate that increases in RVR during the portal vein distension, which is associated with systemic hypotension, may be mediated by an activation of efferent sympathetic renal nerves and modified by at least two neural reflex mechanisms such as carotid sinus baroreceptors and cardiopulmonary baroreceptors. In addition, local reflex systems such as stretch receptors in the venous wall of the portal vein may be involved in excitatory response to renal sympathetic nerve, leading to renal vasoconstriction, during the portal vein distension.

Animals↗
PubMed1985

Some species differences in cardiovascular responses to intravenously injected leucine-enkephalin.

Studies were conducted to determine the cardiovascular responses to leucine-enkephalin (L-enk) in three different species of animals; rabbit, dog and monkey. All animals were anesthetized with pentobarbital sodium after sedation with ketamine. Mean blood pressure (MBP) and heart rate (HR) were simultaneously monitored. The pressor and HR responses to bilateral carotid occlusion (BCO) were determined before injection of L-enk. Increased MBP and HR due to BCO in monkey were significantly greater than in the other two animal groups. Following i.v. injection of L-enk (5-30 micrograms/kg), a significant fall in MBP occurred in all groups in a dose-dependent manner; however, the time course of changes in MBP in rabbits was significantly shorter than that in the other animal groups. Significant decreases in HR after the injection of L-enk occurred in rabbits and dogs, whereas increases in HR occurred in monkeys. These results show that some cardiovascular responses to L-enk may be species dependent. These different cardiovascular responses to L-enk may be at least partly related to species differences in baroreceptor reflex sensitivity.

Animals↗
PubMed1984

No evidence of direct cardiac action of leucine-enkephalin in canine heart-lung preparation.

Intravenous administration of leucine-enkephalin (30 micrograms/kg) caused significant decreases in mean blood pressure, cardiac output, and left ventricular dP/dt in intact dogs. However, cardiovascular effects of leucine-enkephalin (30-120 micrograms/kg) did not occur in the heart-lung preparation uninfluenced by extracardiopulmonary factors. These results provide no evidence of a direct cardiac action of leucine-enkephalin.

Anesthesia, General↗
PubMed1984

Pharmacological evidence that central alpha 2-adrenoceptors are involved in cardiovascular responses to intravenously injected enkephalins in anesthetized dogs.

In anesthetized dogs, intravenous infections of 30 micrograms/kg of leucine- and methionine-enkephalin (L- and M-enk respectively) produced a significant reduction of mean blood pressure (MPB) and heart rate (HR). The peak decreases in MBP and HR occurred within 1 min after injection and recoveries to pre-injection levels within 3 min. The depressor responses to both L-enk and M-enk were abolished by intracisternal pretreatment with yohimbine (0.5 mg/kg) but not with prazosin (0.1 mg/kg). Pretreatment with either drug did not alter the bradycardia. All cardiovascular effects of both L-enk and M-enk were prevented by intravenous pretreatment with naloxone (2 mg/kg). These results suggest that central alpha 2-adrenoceptors may participate in the central actions of enkephalins on blood pressure regulation. HR responses to enkephalins may be elicited by a different mechanism.

Anesthesia, General↗
PubMed1981

Local therapy of carcinoma of the uterine cervix: part I.

One-hundred-fifteen patients with cervical cancer were treated by placing bleomycin, carbazilquinone (Carboquone), and 5-fluorouracil suppositories in contact with cancer lesions located in the vaginal portion of the uterus or by inserting them into the cervical canal, twice a week, one to 14 times. The cancer lesions disappeared form 17 to 33 patients with Stage 0 lesions and 9 of 42 with Stage IA lesions. The remaining lesions were principally found in the deep portion of the cervical glands and tended to decrease the more often the suppositories were applied. This led to the presumption that if this local therapy had been carried on longer it would have eradicated even the remaining lesions from the patients with Stage 0 and IA lesions. The optimal per administration dose of bleomycin appeared to be 30 mg. The use of Witepsol (Dynamit Nobel Aktiengesellschaft, F.R.G.) suppository base was accompanied by frequent adverse reactions to it, which hindered the local therapy from being repeated over long periods of time. An equal amount mixture of hydroxypropyl cellulose and carbomer (Carbopol 934) as the suppository base was accompanied by relatively less adverse reactions, which permitted the prolonged local therapy with the suppositories. A trace of bleomycin was also found in the ovaries, but it did not cause microscopically evident histologic changes, nor did it affect the menstrual cycle. If early cancer can be treated completely by local therapy, it will be useful for the younger patient with early cervical cancer.

Adolescent↗
PubMed1981

[The studies on the individualized treatment and hormonal patterns during the administration of HMG-HCG in anovulatory women (author's transl)].

Repeatedly, we tried to give an devized treatment of HMG-HCG therapy to the three women who had different degree ovulatory disorder. Throughout the study, we observed BBT, cervical mucus and the changes of blood hormones levels until all three women got pregnant. 1) As much difference was bound in the individual ovarian sensitivity to gonadotropin, we observed the ovarian reaction administering of HMG (150 IU) every day. 2) When we observed some maturity of ovarian follicles, we decreased amount of HMG to the level of FSH in the normal menstrual cycle. 3) Considering the days needed to form follicular maturation, we changed HMG to HCG 4 or 5 days after cervical mucus increased to 0.2 ml. or more and showed 2-grade of crystallization.

Adult↗
PubMed1980

Cellular immunity in pregnancy: subpopulations of T lymphocytes bearing Fc receptors for IgG and IgM in pregnant women.

Studies on the change of peripheral T and B lymphocytes and T cells bearing Fc receptors for IgG and IgM in pregnant women were performed by using rosette-formation tests. There was no significant difference in the proportion of T and B lymphocytes between pregnant and non-pregnant women. The percentage of T cells bearing Fc receptors for IgG in the T lymphocytes which are considered to have suppressive activity increased in the various stages of pregnancy and post-partum as compared with that in non-pregnant women. On the contrary, the percentage of T cells bearing Fc receptors for IgM in the T lymphocytes which have a helper function decreased in pregnant and post-partum women. The results of this investigation suggest that the depression of cell-mediated immunity during pregnancy depends on the qualitative change of T lymphocytes, i.e. increased suppressor and decreased helper T lymphocyte subpopulations.

Female↗
PubMed1978

[Temporal relationship of LH and estradiol at mid cycle (author's transl)].

In order to quantitate the feedback effect of estradiol (E2) on the release of LH, serum LH and E2 were measured in 27 ovulatory women daily during the menstrual cycle. The initial rise of LH levels concomitantly occurred when serum E2 concentrations over 100 pg/ml and over 200 pg/ml were maintained for 2 approximately 4 days and for 1 approximately 2 days respectively. The initial rises of LH levels were observed on the day of preovulatory E2 peak. A more detail analysis of the relationship between the two hormones were obtained in five subjects whose blood samples were taken at every eight hours around the time of ovulation. In one among five cases, samples were not obtained early enough to ascertain the relation of the E2 peak to the LH peak. In 3 out of the 4 cases, the intial rises of LH levels occured prior to or concomitant with the time of the E2 peak. By average of all of the five cases, a significant initial rise of LH levels was observed simultaneously with the time of the E2 peak. These results suggest that the increase of the circulatory E2 levels is essential for the initiation of LH surge and their decrease levels are an unrequired mechanism for the midcycle LH release.

Circadian Rhythm↗
PubMed1978

Changes in serum 17alpha-hydroxyprogesterone levels during periovulatory phase in women.

In order to investigate a physiological role of 17alpha-hydroxyprogestone (17-OHP) during the periovulatory phase, serum levels of LH, FSH, estradiol (E2), progesterone (P) and 17-OHP were determined by the radioimmunoassay daily throught the menstrual cycle and during the treatment for induction of ovulation. In 5 ovulatory women serum, values of these hormones were also examined every 8 hr during the periovulatory phase. By average data on five cases whose blood samples were taken every eight hr, the first significant rise in 17-OHP began 8 hr after the time of the E2 peak and the initial rise of LH levels, and the 17-OHP levels increased steeply as E2 falled down from the peak. But in 2 cases among 4, 17-OHP values increased 8 hr prior to or simultaneously with the initial rise of LH and the remaining 2 cases, 17-OHP values started to increase on 16 hr after the initial rose of LH. These results suggest that the mid cycle 17-OHP peak is not a reflection of increased E2 synthesis but that 17-OHP may have a physiological role in inducing and/or facilitating LH release. But this role of 17-OHP in LH release should be further investigated.

Estradiol↗
PubMed1976

Correlation of the pituitary response to synthetic LH-RH to the estradiol levels in anovulatory and ovulatory women.

This paper describes the LH and FSH responses to synthetic LH-RH in 81 anovulatory women and 37 ovulatory women at various estradiol (Ed) levels. Besides, effects of mestranol of releases of LH and FSH in response to LHrh were examined in 4 anovalatory women. Subjects were divided into 3 groups: low Ed group, moderate Ed group and high Ed group. No significant correlation was found in ovulatory women, but in anovllatory women a positive significant correlation was found between the LH/FSH ratio after LHrh injection and the circulating Ed level. In ovulatory women, a mean LH/FSH after administration of LHrh was not significantly different from LH/FSH at the LH peak in the normal menstrual cycle. But in anovulatory women, a mean LH/FSH after the adminitration in the low Ed group was significantly lower than LH/FSH and mean LH/FSH after the administration in two other Ed groups were significantly higher than that at the LH peak in the normal menstrual cycle. Among the low Ed group, four patients with primary ovarian failure and elevated gonadotropin levels in serum were treated with mestranol. With increased doses of mestranol, the LH/FSH after administration of LH-RH was increased and reached to the same level as the normal ovulatory peak in these 4 patients. Our results demonstrated that responses of pituitary gonadotropins to LH-RH in anovulatory women were significantly different in the LH/FSH from those in ovulatory women. Abnormality of these responses in anovulatory women seems to be unfavorable to ovulation.

Adult↗