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Biomedical subjects

K Akagi

Publications and source records attributed to K Akagi.

At least 199 records · Page 11Linked to original sources
PubMed1986

Enhancement of radiation effects by acyclovir.

Acyclovir (ACV), a new antiviral drug, was used to investigate its effect of radiosensitivity in tumors in vivo. In in vivo experiments with Sarcoma-180 transplanted into the ICR mouse and FM3A transplanted into the C3H mouse, ACV enhanced the radiosensitivity of both tumors. In S-180, radiation effects were enhanced by treatment with 100 mg/kg of ACV from 30 min before to 60 min after irradiation. In S-180 treated by 400 mg/kg of ACV, the enhancement ratio was approximately 2.0, as evaluated by the growth delay method. In the FM3A tumor treated by 20 mg/kg of ACV, the enhancement ratio was approximately 1.3, as evaluated by tumor cure (TCD50 assay). ACV is already clinically used as an antiviral drug. Its ability to radiosensitize tumors could therefore have clinical potential when combined with radiotherapy.

Acyclovir↗
PubMed1985

Adrenocorticosteroid therapy and gastroduodenal lesions.

Gastroduodenoscopy was performed in 25 patients with various disorders, such as liver cirrhosis, nephrotic syndrome, and ulcerative colitis, to assess the effects of corticosteroids on the stomach and duodenum. The main criterion for entry into the trial was the absence of open ulcer, healed ulcer, erosion, or bleeding from the stomach or duodenum on pretreatment endoscopy performed within 48 hours before administration of corticosteroids. Endoscopy repeated at 2 to 4 weeks disclosed gastroduodenal lesions in 11 cases (44%)and no lesion in 14 cases (56%). The gastroduodenal lesions observed in 11 cases are as follows: one gastric ulcer (4.0%), six gastric erosions (24.0%), two gastroduodenal erosions (8.0%), and two duodenal erosions (8.0%). A lack of correlation between the patients' subjective complaints and endoscopic findings indicates the unreliability of patients' complaints and the importance of endoscopy in assessing gastroduodenal lesions. There were no differences in the total and average daily doses of corticosteroid between a group with gastric and/ or duodenal lesions and a group without such lesions. Corticosteroids may produce gastroduodenal lesions, regardless of the dose.

Adolescent↗
PubMed1985

A new dosing regimen in renal insufficiency: application to cephalexin.

We describe a new method of drug dosage adjustment. The method simultaneously considers glomerular and tubular functions as parameters, because nonparallel decreases in both functions limit the use of the conventional endogenous creatinine clearance (CLCR) method for dosage adjustment. In the new method, CLCR and the 15-minute phenolsulfonphthalein (PSP15') test were used and applied to patients with renal insufficiency with cephalexin (CEX) as a model drug for renal tubular secretion. The results clearly demonstrate good control of plasma CEX concentrations by the CLCR-PSP15' method, whereas there were marked changes in plasma CEX levels with the CLCR method alone. Our method appears to be more useful for patients with renal impairment than the conventional CLCR method for CEX, which is mainly excreted in urine by renal tubular secretion. A nomogram for the CEX dosing interval is proposed for application to clinical practice.

Absorption↗
PubMed1985

The level of expression of adenovirus type 2 transforming genes governs sensitivity to nonspecific immune cytolysis and other phenotypic properties of adenovirus 2-simian virus 40-transformed cell hybrids.

Syrian hamster embryo cells transformed by adenovirus type 2 (Ad2) or simian virus 40 (SV40) differ markedly in morphology, tumorigenicity, and susceptibility to in vitro lysis by nonspecific cytotoxic cells. Hybrid cells formed by fusing Ad2- and SV40-transformed Syrian hamster embryo cells may express only SV40 T antigens or both SV40 and Ad2 T antigens. Hybrids that express only SV40 T antigens are indistinguishable from the nonhybrid SV40-transformed phenotype, whereas hybrid cells that express T antigens from both viruses closely resemble the nonhybrid parental Ad2-transformed phenotype. Because these hybrid cells have been useful in the study of neoplastic transformation, we determined the amount of viral antigens that they accumulate in an attempt to correlate the level of expression of the transforming viral genes with some of their phenotypic properties. Hybrid cells that expressed proteins from both viruses showed reduced levels of SV40 T antigens compared with those of hybrid cells that did not express Ad2 T antigens. We also found that the production of several cellular proteins that influence cytomorphology was inhibited in hybrid and nonhybrid cells that expressed Ad2 T antigens, and the repression of these cellular proteins correlated with a change in cytomorphology from fibroblastic to spherical. Finally, we showed that the susceptibility of our hybrid cells to in vitro lysis by natural killer cells and activated macrophages, two putative host-effector cells involved in defense against neoplasia, correlated closely with the level of expression of a 58,000-dalton Ad2 protein. The results reported here, together with the results of previous studies, indicate that the oncogenic potential of hybrid cells that express both Ad2 and SV40 antigens is extremely sensitive to Ad2 expression, whereas other phenotypic properties depend on Ad2 expression in a dose-dependent manner.

Actins↗
PubMed1985

Association of blood pressure and PCB level in yusho patients.

Correlations of blood polychlorinated biphenyl (PCB) levels or PCB patterns and blood pressures were studied in 59 patients with yusho (PCB poisoning) above 40 years old. In spite of the passage of 13 years from the onset, 52.5% of these patients still have PCB levels higher than the range found in the general population. The frequency of hypertension in the patients was 16.9%, a value similar to that expected on the basis of the rate for a population of the same age and sex compositions. As an independent variable, the blood pressure of patients was not associated with blood PCB levels and PCB patterns. No PCB blood pressure association was confirmed in 20 patients with PCB levels persistently higher than 5 ppb for 9 years. On the other hand, age, obesity and habitual alcohol intake, known influencing factors for hypertension, tended to be positively associated with elevated blood pressure in these yusho patients.

Adult↗
PubMed1985

A method for making chronic fetal preparation in the lamb: results of 4 year's experiences.

During the period between 1980 and 1983, a versatile experimental model for fetal physiology (chronic fetal preparation) was made using 26 pregnant Corriedale and Suffolk sheep. The sheep fetuses were removed from the uterus at the gestational ages of from 96 to 133 days. After performing cannulation of the carotid arteries, the jugular veins , and the trachea of the fetuses, applying tripolar cardioelectrodes, and attaching an occluder of the umbilical cord, the fetuses were returned to the uterus to complete the gestational period. The time left until the termination of the postoperative pregnancy and available for various intrauterine monitoring procedures varied from 3 to 800 hr. Eleven sheep (42.3%) continued their postoperative intrauterine term for 5 days or more. The continuation of the postoperative gestation for longer than 5 days indicated a return to the physiological state on the evidence of the measured PO2, PCO2 and pH values and rapid irregular breathing movements.

Anesthesia, Epidural↗
PubMed1984

[Problems of antineoplastic effects by PLDR (potential lethal damage repair) inhibitor--pharmacokinetics].

PLDR is one known cause of tumor cell radioresistance. Drugs like ara-A have been reported to inhibit PLDR, thus increasing antineoplastic effects. In this research, ara-A concentration was measured by high-pressure liquid chromatography (HPLC) to investigate its metabolism. Ara-A deaminases in vitro in about 30 minutes, but by using a deaminase inhibitor such as 2'-deoxycoformycin, a fixed level of ara-A can be maintained. Furthermore, the new derivative, ara-AMP, does not deaminase. It is hoped that antineoplastic effects can be effectively increased by maintaining the ara-A concentration through the combined use of deaminase inhibitors and through new derivatives.

Adenocarcinoma↗