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Biomedical subjects

N Yamada

Publications and source records attributed to N Yamada.

At least 919 records · Page 51Linked to original sources
PubMed1981

[Changes of blood-brain barrier in the ethylnitrosourea induced rat glioma (author's transl)].

Capillary permeability of rat brains bearing ethylnitrosourea induced rat glioma was measured with quantitative autoradiography. In the small tumors (less than 2mm in diameter), no changes in capillary permeability was noted. When tumors became larger and neovascularization of the tumor occurred, increase in capillary permeability was evident. This change was more prominent in the center of the tumor than in the periphery. In the large tumors, the capillary permeability was markedly increases, and the value was similar to that in the choroid plexus. This indicates that blood-brain barrier(BBB) completely disappeared in the large tumors. This BBB change may be the main cause of tumor induced brain edema. The data also provide the information about pharmacokinetics of water soluble drugs in the brain tumors.

Animals↗
PubMed1981

An experimental model of toxemia of pregnancy in spontaneously hypertensive rats (SHR).

The use of an animal model in the study of human diseases has proven a valuable tool for medical science. The main syndromes in human toxemia of pregnancy are hypertension, edema, and proteinuria. Because of their hypertension, pregnant spontaneously hypertensive rats (SHR) can be considered to represent a type of toxemia of pregnancy according to the classification of the Japan Society of Obstetrics and Gynecology. As no edema and only a small amount of proteinuria were observed in SHR, we induced massive proteinuria and edema by injecting pregnant SHR with puromycin. After this treatment, proteinuria of 100-300 mg/dl was continually observed throughout their life span, with pregnancy and delivery occurring 2-4 times. From our findings we have attempted to produce a model of human toxemia of pregnancy.

Animals↗
PubMed1981

Severe energy restriction in treatment of toxemia of pregnancy.

A total of 78 patients with toxemia pregnancy were treated for over a week before delivery. The treatment was characterized by (1) mental and physical rest, (2) disuse of hypotonic, diuretic, and antispasmodic agents, and (3) a diet with reduced salt and energy (200-1200 Cal/day). Except for one fetal death, which occurred during delivery, all mothers and their babies left the hospital in good condition. No fetal or neonatal deaths that were related to the maternal condition or severity of toxemia were encountered. The long-lasting complications of toxemia were lower than those reported by others. No critical accident was noted. Our treatment proved to be efficient in the treatment of toxemia.

Adult↗
PubMed1981

Hypertensive effects on pregnancy in spontaneously hypertensive rats (SHR) and stroke-prone SHR (SHRSP).

We studied the hypertensive effects on mothers and newborns in Wister Kyoto rats (WKY), spontaneously hypertensive rats (SHR), and stroke-prone SHR (SHRSP). The average blood pressure of pregnant rats in WKY, SHR, and SHRSP was 100, 180, and 210 mmHg, respectively. The average adult female weight and weight gain during pregnancy were inversely proportional to the increase of hypertension. The rate of delivery, reproduction, litter size and their weight were lowest in the SHRSP.

Animals↗
PubMed1980

[The effects of estradiol on uterine estrogen receptor and thymidine kinase in immature and spayed-adult rats (author's transl)].

Uterine estrogen receptor (ER) and thymidine kinase (TK) activity were investigated in response to an injection of estradiol (E2) (1.43microgram/100g body weight) in SD-strain immature female rats aged 21 days and spayed-adult rats aged 104 days (14 days after castration). In immature rats, uterine cytosol ER decreased abruptly after the injection of E2 and increased gradually from 4 hours later. On the other hand, nuclear ER increased rapidly and shaped a peak 1 hour after the injection of E2 and decreased gradually afterward. Uterine TK activity began to increase rapidly from 18 hours and shaped a peak 24 hours after the injection of E2 and was reduced to the same level as the controls 48 hours later. No differences in behavior of uterine cytosol and nuclear ER after the injection of E2 between immature and spayed-adult rats were noticed. Although uterine TK activity in immature rats was stimulated 30 times 24 hours after the injection of E2, that of spayed-adult rats increased by only twice. Uterine TK was separated into 3 fractions (A, B and C) by means of a DEAE-cellulose column chromatography. In immature rats, 95% of the great TK activity induced by E2 was involved in fraction A, which was not inhibited by dCTP. In contrast, uterine TK isozymes in spayed-adult rats were at fraction B and C, whose activities were inhibited by dCTP, without relation to the administration of E2. The molecular weight of fraction A was estimated to be approximately 125,000 and that of B was 100,000 by the method of gel filtration on a Sepharose CL-6B column. No differences in uterine ER levels between immature and spayed-adult rats were found, but E2-induced different TK isozymes seem to depend on the stage of uterine growth.

Animals↗
PubMed1980

Differences in the induction of thymidine kinase isozymes in estrogen-treated immature and adult rats.

Thymidine kinase activity in immature and castrated adult rat uterus has been examined in response to estrogen treatment. Following estrogen administration, it was found that immature uterine thymidine kinase activity was increased 30-fold after 24 h, but almost no effect was produced on castrated or non-castrated adult uterus. Uterine thymidine kinase activity was separated into three peaks (peak 1, 2 and 3) by means of DEAE-cellulose column chromatography. In response to estrogen, the thymidine kinase isozymes differed in adult and immature uteri. In immature uteri, marked and selective increase of the activity was found in peak I, whereas in adult only a slight increase in peak 2 activity was observed. The thymidine kinase activity in peak 1 and peak 2 were found to have different enzymatic properties and molecular weight, as determined by gel filtration of 125 000 for peak 1 and 100 000 for peak 2. From these results, it is suggested that estrogen induces specific thymidine kinase isozyme in immature uterus and that the isozyme may be involved in DNA synthesis. Such a induction mechanism seems to be lost during the development.

Animals↗
PubMed1980

Application of cephalosporins to obstetrics and gynecology: transfer of cefazolin and cephalothin to uterine tissue.

Antibiotics should be administered so as to maintain effective therapeutic levels in target organs. In routine clinical treatment, however, doses of antibiotics are determined on the basis of their achievable concentrations in blood. To determine the optimum doses of antibiotics against obstetric and gynecologic infections, the authors gave a single intravenous dose of 2 gm of cefazolin or cephalothin to 51 patients before hysterectomy and measured the levels of the antibiotics in uterine tissues and compared them with corresponding serum levels. The maximum tissue levels of cefazolin were generally about 6 to 7 times higher than those of cephalothin: In tthe perimetrium, levels were 154 microgram/gm for cefazolin and 24.1 microgram/gm for cephalothin; in the myometrium, 109.5 microgram/gm for cefazolin, and 15.5 microgram/gm for cephalothin; and in the endometrium, 98.9 microgram/gm for cefazolin and 10.4 microgram/gm for cephalothin. In the tissues, however, cephalothin reached peak levels more rapidly than cefazolin. Comparisons of the tissue levels and MIC of cefazolin and cephalothin revealed that cefazolin was maintained at over 12.5 microgram/gm for at least 150 minutes in the perimetrium, myometrium, and endometrium, whereas cephalothin was maintained at these levels for 40 to 50 minutes only in the perimetrium and myometrium. The ratio of tissue levels to serum levels was 40-70 to 100 for cefazolin and about 30 or less to 100 for cephalothin.

Adult↗
PubMed1980

Decline of postheparin plasma lipoprotein lipase in acromegalic patients.

Lipoprotein lipase and hepatic triglyceride lipase in postheparin plasma were measured in seven patients with active acromegaly by an immunochemical method utilizing antiserum prepared against hepatic triglyceride lipase. A mild or moderate hypertriglyceridemia was shown, with plasma triglyceride concentrations between 156 and 544 mg/dl. Lipoprotein lipase was found to be decreased in all patients (p less than 0.001). Hepatic triglyceride lipase was also low in these patients (p less than 0.001). We speculate that acromegalic hypertriglyceridemia is mediated, at least in part, by the decline in lipoprotein lipase and possibly by the decline in hepatic triglyceride lipase activities.

Acromegaly↗
PubMed1980

A method for the repair of transverse facial clefts.

In the natural form of the oral commissure, the outer edges of the upper and lower lips form small triangular flaps. The white line of the lip at the commissure is web continuous with the upper and lower red lips. The lower part of this web is larger than the upper. To repair this so that there is a natural appearance, a Z-plasty and mucocutaneous flap based inferiorly is performed on the transverse facial cleft. The incision line for the Z-plasty is made though each vermilion border and is extended approximately 1.5-2 mm to create the web continuous with red lips. The mucocutaneous flap is formed when making the incision through the lower vermilion border. As the flap is elevated and sutured to the upper lip, the larger web-like skin on the lower lip is made. This skin is seen to insert boldly into the oral cavity.

Humans↗
PubMed1979

A selective deficiency of hepatic triacylglycerol lipase in guinea pigs.

The properties of postheparin plasma triacylglycerol-hydrolyzing enzymes were investigated in guinea pig and rat. In rat, lipoprotein lipase and hepatic triacylglycerol lipase were separated on a heparin-Sepharose affinity chromatography. In postheparin plasma of guinea pig, however, hepatic triacylglycerol lipase was almost completely absent, while lipoprotein lipase was present. Hepatic triacylglycerol lipase was also deficient in the liver tissue extract of guinea pig. Plasma lipoprotein compositions of high-fat fed and control guinea pigs were analyzed. One of the outstanding changes found in high-fat fed animals was the presence of chylomicronemia. One guinea pig showed gross hyperlipemia with triacylglycerol concentrations of 2715 mg/100 ml. Plasma triacylglycerol concentrations of each lipoprotein fraction of very low density, intermediate density, low density and high density lipoproteins from high-fat fed animals were almost the same as those of the corresponding lipoprotein fractions from controls. Discussion was focused on the development of chylomicronemia in relation to the defects of triacylglycerol-hydrolyzing enzyme systems in this animal.

Animals↗