Endothelium-intact rat aortic rings were incubated with palytoxin (PTX, 10(-11)-10(-9)M, 10 min) in oxygenated (O2 95%, CO2 5%) baths. Phenylephrine (PE)-contracted vascular rings demonstrated decreasing relaxation to acetylcholine (ACh), depending upon PTX incubation in a dose-dependent manner; however, sodium nitroprusside (NaNP) persisted in returning the ring to its pre-PE tension. After incubation with PTX, relaxation to the receptor-independent, endothelium-dependent relaxant A23187 was also attenuated. Thus, endothelium-dependent mechanism(s) normally responsive to both ACh and A23187, stimulators of nitric oxide (NO) release, were disrupted. Following incubation with PTX, endothelium-independent relaxation to NaNP remained intact but relaxation to atriopeptin II (APII) decreased. Electron microscopy demonstrated microvesiculation of endothelial cell cytoplasm and an irregular luminal surface following incubation with PTX. The intact response to NaNP, despite the loss of relaxation to ACh, indicated that soluble guanylate cyclase was not affected by PTX. However, loss of relaxation to AP-II, involving particulate guanylate cyclase of vascular smooth muscle (VSM), was inhibited by PTX pre-incubation. Determination of the site(s) of action of PTX requires further study.

Acetylcholine↗

PubMedDate not supplied

A prospective comparative study of transvaginal ultrasonography and digital examination for cervical assessment in the third trimester of pregnancy.

Digital examination of the cervix has traditionally been the "gold standard" for cervical assessment. However, it can be subject to inter- as well as intra-observer variation. The usefulness of transvaginal ultrasonography for cervical assessment is examined in this study. Although differences between measurements of transvaginal ultrasonography and digital examinations were observed, transvaginal ultrasonography appears to be a potentially useful and reproducible technique for assessing cervical changes in pregnancy and for prediction of onset of labor.

Cervix Uteri↗

PubMedDate not supplied

Effect of allopurinol on the formation of reactive oxygen species during intense exercise in the horse.

Allopurinol was administered to six horses in a cross-over study to determine the relative contribution of xanthine oxidase (XO) activity to the formation of reactive oxygen species (ROS) in the horse during intense exercise. Exercise increased the mean (SEM) plasma lipid hydroperioxide concentration to a maximum of 492.7 (33.4) microM within one minute of exercise completion and maximum levels of both oxidised glutathione (GSSG) in haemolysates of red blood cells and the glutathione redox ratio (GRR) occurred 20 minutes after exercise (87.2 [12.2] microM and 8.9 [0.9] per cent, respectively). Allopurinol significantly reduced lipid hydroperoxides, GSSG and the GRR at the corresponding maximal times after exercise measured during control exercise (217.5 [32.1] microM. 63.8 [8.6] microM and 6.8 [0.7] per cent, respectively). Significantly higher levels of hypoxanthine and xanthine were measured after exercise in the plasma of horses that received allopurinol than in control horses, although uric acid levels remained constant. In control horses, plasma uric acid concentrations increased after exercise to a maximum 20 minutes after exercise of 28.1 (2.6) microM, significantly higher than in horses given allopurinol (9.6 [1.3] microM). The results show that the inhibition of XO by allopurinol leads to a decrease in the formation of ROS during exercise, and thus a reduction in oxidative stress.

Allopurinol↗

PubMedDate not supplied

Zoledronic acid improves the mechanical properties of normal and healing bone.

OBJECTIVE: To determine the effects of the bisphosphonate zoledronic acid on the mechanical properties of normal and regenerating bone in a rabbit model of distraction osteogenesis. BACKGROUND: Bisphosphonate therapy is used for treating osteoporosis and, more recently, to enhance bone healing and reduce stress-shielding osteoporosis in distraction osteogenesis. METHODS: Thirty eight rabbits underwent 14 days of distraction osteogenesis on the right rear limb. They received either zero, one or two doses of intravenous zoledronic acid. Four point bending tests were performed to collect mechanical data. RESULTS: The peak load capacity of the regenerating bone was significantly increased by bisphosphonate therapy, but a similar trend in normal bone was not significant. The energy absorbed to failure did not vary significantly in either group. CONCLUSIONS: These data suggest that bisphosphonate therapy has a beneficial effect on the load capacity of regenerating bone, without increasing the brittleness of either new or existing bone. RELEVANCE: Zoledronic acid administration may be a potentially valuable adjunct to distraction osteogenesis treatment, to enhance bone strength, thus reducing refracture complications.

Animals↗

PubMedDate not supplied

Ultrasonic measurement of biparietal diameter and femur in foetal age determination.

Our objective was to verify ultrasonic measurement of biparietal diameter and femur in foetal age determination in the second and third trimester of pregnancy. The prospective cross sectional study was carried out at the ultrasound department of Aberdeen Maternity Hospital Scotland. The study population consisted of 716 pregnant Scottish (Caucasian) women who were certain of their gestational ages and had their gestational ages confirmed in the first trimester by ultrasound. The findings revealed: (1) Linearity through out pregnancy using the femur length measurements while that of the biparietal diameter demonstrated poor correlation after 32 weeks of gestation. (2) The standard deviation and the correlation coefficient of the femur length measurements were 0.0042 and 0.9920 respectively while the corresponding values for biparietal diameter were 0.0045 and 0.9850 respectively. (3) The standard error for femur length estimate was 0.2251 as against 0.3009 for biparietal diameter estimate. The results suggest that femur length measurement is a more reliable index of late third trimester gestational age prediction than biparietal diameter.

Cephalometry↗

PubMedDate not supplied

The case of the high-risk safety product.

After several days of meetings, J.F. Winchester, president of MDC Industries, felt no closer to a decision. MDC, a manufacturer of wall and ceiling panels, was considering whether to exercise an option to buy a new and safer wallboard technology. The product was being touted as revolutionary, but, Winchester wondered, could MDC afford to carry the flag? According to its inventor, Robert Goerner, Smoke-Safe would be a vast improvement over standard safety-rated wallboard. With almost the same flame-retardant properties, Smoke-Safe had the advantage of giving off almost no fumes or smoke in fire tests. And, Winchester knew, most fire-related deaths are from smoke, not flames. Indeed, the numbers were grimly persuasive: 82% of fire-related injuries involving standard panels were caused by smoke inhalation. What's more, Smoke-Safe would cost about the same to manufacture as MDC's current wallboard. But MDC had several other good options for spending the $5 million Goerner was asking; building plastics was only one of its profit centers. And the prospect of launching a campaign to change building codes in order to market Smoke-Safe, which could spark a fight with competitors, was daunting. Since its current wallboard gave MDC only 18% of the wallboard market, many industry insiders speculated whether MDC had the market clout to influence major cities to revise their codes. Six experts in marketing, law, and ethics advise MDC Industries on how it can balance ethical and business imperatives in making its decision.

Consumer Product Safety↗

PubMedDate not supplied

Supracondylar fractures of the femur in children.

Nonphyseal supracondylar fractures of the femur are considered to be uncommon in children and have received little attention in the literature. A retrospective review of femoral fractures in children at the authors' institution was undertaken to ascertain the incidence of supracondylar femoral fractures, the influence of associated musculoskeletal conditions, and pitfalls of management. In this study of 102 femoral fractures, there was an incidence of 12% of supracondylar fractures. Four of 12 patients had a significant predisposing musculoskeletal condition contributing to the genesis of the fracture. Five fractures were undisplaced and easily managed. Seven displaced fractures required intervention to achieve an adequate reduction. The literature is reviewed and a classification system for these fractures is presented. Treatment options are discussed and recommendations made based on this experience.

Adolescent↗

PubMedDate not supplied

Effects of cimetidine, antipyrine, and pregnenolone carbonitrile on misonidazole pharmacokinetics.

We investigated the effects of cimetidine, antipyrine, and pregnenolone carbonitrile on the pharmacokinetics of misonidazole (MISO) in mice. antipyrine did not induce MISO demethylation. Considerable induction was seen with pregnenolone carbonitrile, but it was not superior to phenobarbital. Cimetidine inhibited MISO demethylation and increased its half-life and area under the curve. We suggest that patients receiving cimetidine and MISO have their MISO pharmacokinetics carefully monitored.

Animals↗