To determine the usefulness of transvaginal ultrasonographic cervical assessment for the prediction of preterm delivery in an apparently normal population, 729 pregnant women (between 15 and 34 weeks' gestation) were randomly enrolled in the study in ten tertiary perinatal centers in Japan. Cervical parameters, including cervical length, internal os dilatation, and funneling depth, were measured by transvaginal ultrasound. The predictive values of these measurements for preterm delivery were investigated in a prospective fashion. Among various cervical parameters, cervical length showed the best correlation with pregnancy outcome. Cervical length (mm) was gradually decreased as the gestational age progressed, the regression line being y = 41.21-0.22x. When the mean cervical length minus 1 standard deviation at each gestational age was chosen as a cut-off value, the group with a shortened cervix showed a significantly high preterm delivery rate exclusively in the primigravidae (odds ratio: 4.86, 95% CI: 1.85-12.72). Internal os dilatation, in contrast, was a useful predictor in multiparous women (odds ratio: 6.00, 95% CI: 1.65-21.71). It was concluded that tranvaginal ultrasonographic cervical assessment, especially the measurement of cervical length, was effective for the prediction of preterm delivery in the primigravidae.

Cervix Uteri↗

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Upper hemibody infusion of cis-diamminedichloroplatinum (II) followed by systemic antidote, sodium thiosulfate, for lung metastasis in rats.

Effects of a combination chemotherapy using cis-diamminedichloroplatinum (II) (DDP) and its antidote, sodium thiosulfate (STS), on metastatic lung tumour in rats were studied. Rats were given an upper hemibody infusion (UHI) of 15 mg/kg DDP immediately after occlusion of the abdominal aorta and i.v. administration of 1581 mg/kg STS (200-fold molar ratio to DDP) 10 min later. The aortic clamp was released at approximately 11 min after the beginning of UHI when a half volume of STS solution was infused. Antitumour and side effects in this group were compared with those in the respective control groups given 5 mg/kg DDP alone by UHI or by systemic administration. In the group given UHI of DDP (DDP-UHI) in combination with STS, there was a significantly better antitumour effect than seen in the group given DDP alone, as evaluated by the number of lung tumour nodules and survival time after inoculation of the transitional cell carcinoma into the lung. Nephrotoxicity, as assessed by increase in BUN levels, was completely avoided. Haematological toxicity effects assessed by decreases in WBC were slight but body-weight loss due to anorexia was severe.

Animals↗

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Effect of ascorbic acid deficiency on primary and reparative dentinogenesis in non-ascorbate-synthesizing ODS rats.

Ascorbic acid is essential to the biosynthesis of collagen, the major organic matrix component of dentine. The ODS rat is a mutant strain of Wistar rat characterized by hereditary lack of L-gulono-gamma-lactone oxidase and thus is unable to synthesize ascorbic acid. ODS rats were given an ascorbic acid-free diet to investigate how ascorbic acid deficiency affects dentine formation in vivo. Histomorphometric analysis on their growing molars and incisors showed a significant reduction in both size and mineral apposition rate of dentine, as revealed by contact microradiography and fluorescent time-marking, respectively. A similar reduction in bone formation was simultaneously demonstrated in the mandible, confirming the previously reported osteopathic effects of ascorbic acid deficiency. When pulp inflammation was induced in lower first molars by making unsealed pulp exposures, specimens from control animals showed continuous deposition of an osteodentine-like tissue in the radicular pulp chamber; this type of mineralized tissue formation was greatly reduced in ascorbic acid-deprived animals. These results indicate that ascorbic acid deficiency hampers dentine formation under both physiological and pathological conditions of the dentine/pulp complex. ODS rats could be useful in investigating in vivo effects of ascorbic acid deficiency on the formation of dentine and other dental mineralized tissues.

Animals↗

PubMedDate not supplied

Genome analysis of adenovirus type 4 strains isolated from acute conjunctivitis in Japan.

Strains of adenovirus type 4 (Ad4) isolated from patients with acute conjunctivitis were studied by DNA restriction analysis. The strains were isolated between July and December 1990 in Japan. All 63 isolates of Ad4 were identified as the genome type Ad4a. This study showed that the same Ad4 genome type, Ad4a, caused acute viral conjunctivitis, even in different areas of Japan.

Acute Disease↗

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Effects of neurectomy and tenotomy on the bone mineral density and strength of tibiae.

The right hindlimbs of 5 or 6-week old Wistar male rats were sciatic/femoral neurectomized, tenotomized or sham operated. The rats were sacrificed 2 weeks after the surgery and the tibiae were removed. pQCT measurement was performed on total, cortical, and trabecular bone separately at different regions. Reduction of the bone mineral density by unloading was observed more significantly at metaphysis than at diaphysis due to histological heterogeneity between metaphysis and diaphysis; metaphysis is rich in trabecular bone and diaphysis is abundant in cortical bone. Trabecular bone might be more sensitive to unloading because the reduction rate of volumetric bone mineral density in trabecular bone was approximately 10 times and 3 times larger than that of cortical bone in both neurectomy and tenotomy rats, respectively, Unloading also reduced the cross-sectional area and stress strain index at metaphysis.

Absorptiometry, Photon↗

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Growth factors: roles in andrology.

Mesenchymal-epithelial interactions are extremely important during growth and development and in the functional cytodifferentiation of male sex accessory organs. Interactions between mesenchyme and epithelium occur mainly through a paracrine action that is mediated by various growth factors. The role of androgens is very important for these organs and the androgenic effect is mediated by paracrine interactions. A number of growth factors have been studied in prostate and seminal vesicles from mice, rats, and humans because they are potent mediators of cellular proliferation, differentiation, and death. This review provides an overview of current knowledge about growth factors involved in the development of male sex accessory organs, with particular emphasis on the prostate.

Androgens↗

PubMedDate not supplied

Direct cardiac potential trigger for chronic control of a ventricular assist device.

As a new trigger method for chronic drive control of a ventricular assist device (VAD), a direct cardiac potential trigger was assessed under various conditions in a chronic experimental model. A pneumatic pulsatile VAD was implanted as circulatory support between the left ventricular apex and the ascending aorta in 12 adult pigs. Hemodynamic parameters and pump output were continuously monitored. Two tips of a bipolar electrode were set on the RV anterior wall and the LV posterior wall for recording direct cardiac potential. Counterpulsation drive of the VAD was applied by using the R wave in a standard electrocardiogram (ECG) or the direct cardiac potential as an ECG trigger. As special conditions, various artifacts on ECG, electromusculogram, arrhythmia, irregular ventilation, and passive vibration (simulation of exercise) were set for assessing the ECG trigger modes. Artifacts of irregular ventilation and passive vibration made the drive control poor using a standard ECG trigger. In contrast, the direct cardiac potential trigger maintained the counterpulsation control of the VAD well in all conditions of this study, and was a safe and reliable support for the native heart. It also supported animals for up to 48 hours after operation. The above results suggested that the direct cardiac potential trigger might be useful for monitoring native heart beats and adjusting the support cycle to the native heart cycle as a chronic control method for various VADs.

Animals↗

PubMedDate not supplied

Quantitative changes of maximum contractile response to norepinephrine in mesenteric arteries from spontaneously hypertensive rats during the development of hypertension.

Maximum contractile responses of mesenteric arterial strips from spontaneously hypertensive rats (SHR) to norepinephrine (NE) were determined at all stages of hypertension (6-30 weeks of age), and data compared with findings in normotensive Wistar-Kyoto rats (WKY). Although the maximum responses to NE in the strips from both 6- and 14-week-old SHR--that is, before and after the development of elevated blood pressure--were significantly greater than those in the strips from age-matched WKY, the ratio of the maximum contraction induced by NE to that by KCl (NE/K+ ratio) was increased only after the development of hypertension. The difference in the NE/K+ ratio was also apparent in strips of femoral artery from 14-week-old rats but not in strips of thoracic aorta. The angiotensin II/K+ ratios in the three arterial strips, which were significantly decreased with advancing age of the rats, were not significantly different between the SHR and WKY. There was a good correlation between the NE/K+ ratios in the mesenteric arterial strips and the blood pressures of both SHR and WKY. It is concluded that the NE/K+ ratio in the mesenteric arterial strips was in good agreement with the onset of hypertension in SHR.

Aging↗

PubMedDate not supplied

Hepatocyte regeneration after partial hepatectomy occurs even under severely thrombocytopenic conditions in the rat.

In order to investigate the role of blood platelets in regenerative proliferation of hepatocytes in vivo, partial hepatectomy was carried out under conditions of severe thrombocytopenia achieved by X-irradiation and the time-dependent degree of hepatocyte regeneration was measured as labeling index (LI) after 3H-thymidine injection. LI values reached a maximum 36 h after hepatectomy performed 7 days subsequent to a whole-body irradiation of 7.5 Gy, although the maximum rate was found to be only about one-third of that found in unirradiated control rats. At this time point, the number of peripheral blood platelets was decreased to about 2% of that of unirradiated controls and bone marrow megakaryocytes were virtually undetectable. A decrease of LI, similar to that found for the whole-body irradiation in degree, was also observed after local irradiation of the liver with the same dose but without an apparent decrease in platelets. When whole-body irradiation was performed with the liver shielded, under which conditions the numbers of blood platelets decreased to about 8% of the control levels, almost no decrease in LI was found. The results thus suggest that the observed inhibition of hepatocyte regeneration was directly due to liver irradiation and that depletion of blood platelets itself does not interfere with the regeneration process, providing evidence against a dominant role of the platelets in the regeneration as proposed by other authors.

Animals↗