Blood flow in human temporal muscle during tooth grinding and clenching as measured by 133Xenon clearance

abstract — Six healthy human subjects performed grinding and clenching of teeth, to assess if pain releasing and strenuous muscular exercise causes a decrease or total stop of the blood flow through the temporal muscles, as measured by ¹³³Xenon clearance. The mean blood flow/volume of muscle tissue was 25.4 ml×min⁻¹×l⁻¹ during rest, whereas the mean flow was 101.8 ml×min⁻¹×l⁻¹ during grinding, and 62.9 ml×min⁻¹×l⁻¹ during clenching. It is suggested that facial pains induced by strenuous exercise of the jaw muscles are not due to ischemia. On the contrary, the blood flow seems to increase about 300% during grinding and about 150% during clenching.     

Turbulent Stresses Downstream of Porcine and Pericardial Aortic Valves Implanted in Pigs

Because late valve-related complications such as hemolysis and thromboembolic events are considered related to flow disturbances caused by the inserted valve, velocity fields downstream of aortic valve prostheses were studied in pigs. Acute hemodynamic evaluation of size 25-mm porcine and pericardial aortic valve prostheses 1 diameter downstream of the valve ring was performed using dynamic three-dimensional visualization of velocity profiles and spatial distribution of turbulence. Point blood velocity signals obtained with a 1-mm hot-film anemometer needle probe were used to compute Reynolds normal stresses (RNS) by calculation of the turbulent velocity energy of the axial velocity component in the systole. The porcine valves caused a skewed velocity and turbulence profile revealing mean spatial systolic RNS at 70 nm-2 +/- 35 nm-2 (+/- SD). The spatial maximum RNS was 275 +/- 139 nm-2. Corresponding values for the pericardial valves were 20 +/- 11 nm-2 and 72 +/- 46 nm-2. The pericardial valves revealed plug-shaped velocity profiles and turbulent profiles with slightly higher RNS values at the stent posts. From a hemodynamic point of view, these acute studies indicate superiority of the pericardial valves compared to the porcine valves. The turbulent stresses found in this study are of a magnitude that may cause blood corpuscular and endothelial damage.     

Progressive Pulmonary Fibrosis Complicating Cyclophosphamide Therapy

ABSTRACT. Stentoft J (Department of Internal Medicine and Haematology, Aalborg Hospital, Aalborg, Denmark). Progressive pulmonary fibrosis complicating cyclophosphamide therapy. A 26-year-old woman with extra-pulmonary Wegener's granulomatosis was treated with cyclophosphamide for 3.25 years, cumulated dose of 91 g. Six months before cessation of therapy discrete radiological signs of apical fibrosis appeared. The changes were progressive regardless of discontinuation of cyclophosphamide and led to severe restrictive ventilatory defect.     

Smoking habits in relapsed subjects from a smoking cessation trial after one year

Reports of smoking cessation studies often claim that many relapsed subjects reduce their smoking. We investigated the smoking habits of relapsers 1 year after quitting in a smoking cessation trial using nicotine or placebo patches. All 289 participants in that study were summoned to a 1-year follow-up visit–148 (57%) of 259 relapsers attended, as did all 30 sustained abstainers. Fewer than 1% of the subjects had quit spontaneously after the primary relapse. Daily cigarette consumption, standard nicotine yield per cigarette, saliva cotinine concentration, expired carbon monoxide level and two nicotine dependency scales were assessed at entry and at the 1-year follow-up. In five of these six smoking-related characteristics, there was a small but significant mean reduction of 7%-27%. A significant weight gain of 0.5 ± 2.9 kg (mean ± SD) was recorded in the relapsers compared with 4.8 ± 4.2 kg for abstainers (p < 0.001). It is concluded that smoking habits in relapsers are relatively unchanged, and thus the most important outcome measure in smoking cessation trials is abstinent subjects.     

Carcinogenesis in forestomach and changes in oral mucosa of rats induced by intragastric N-methylnitrosourea

Abstract – it is well known that oral administration oi N-methylnitrosourea (NMU) induces carcinomas in the forestomach of experimental animals. As the rat forestomach is lined with an orthokeratinized squamous epithelium the purpose of the present study was to elucidate whether carcinogenesis in this localization following intragastric application of NMU was comparable to oral carcinogenesis in experimental animals and humans. Furthermore, the development of oral m u cos al lesions in the rats was studied. It is concluded that the morphologic changes seen during carcinogenesis in the forestomach do not seem to differ essentially from those seen during experimental and human oral carcinogenesis. Furthermore, the number of oral lesions found in the present study are higher than reported in other strains of rats following administration of NMU.     

Outcome of sterilization by steam autoclaves in Danish dental offices

Abstract — The aims of this study were to evaluate the performance of autoclaves and the use of biologic indicators for sterilization control, and to look for predictor variables for improperly functioning autoclaves in Danish dental offices. The study population comprised 314 Danish dental offices (participation rate 94%); 177 from the public Child Dental Service (CDS) and 137 from private practice. A minor questionnaire and five biologic indicators, (Attest Biological Indicator for Steam Sterilization, 3M) were sent to the participants. CDS offices were found more inclined to use biologic indicators than PP offices ( P <0.00001). Among CDS autoclaves 2.3% (95% confidence limit: 0.9–5.7%) failed to sterilize compared to 7.3% (95% confidence limit: 4.0–12.9) of the PP autoclaves. This difference is not statistically significant, but the confidence intervals indicate a possible true difference in favor of a better outcome in the CDS offices. Looking at the whole sample no other predictor variable for inadequate sterilization could be determined as differences were statistically insignificant with regard to years of professional experience, age and brand of autoclave, and use of biological control. Recommendations from an official body stating the approved types of sterilization control in dental offices would be of value.     

Anxiety in adolescents born preterm or with very low birthweight: a meta‐analysis of case–control studies

Aim To determine if adolescents who are born very preterm (<32wks; of gestation) and/or with very low birthweight (VLBW; <1500g) have a higher risk of experiencing clinically significant anxiety problems. Method We used a systematic review and meta‐analysis. We searched the databases ISI Web of Knowledge, PubMed, PsycNET, Educational Resources Information Center (ERIC), Latin American and Caribbean Literature on the Health Sciences (LILACS), and Virtual Health Library (VHL) with equivalent search expressions (from the databases’ inception to June 2011). Also, we screened reference lists of identified articles. We selected case–control studies of adolescents 11 to 20 years old who were very preterm/VLBW and had a matched reference group born at term with normal birthweight that reported a validated anxiety outcome measure. For data extraction, two authors independently reviewed titles, abstracts, and full articles identified through the searches. Subsequently two authors independently extracted data. Results We included six studies with 1519 adolescents (787 very preterm/VLBW, 732 comparisons). The general risk of developing clinically significant anxiety problems was nearly doubled (p<0.05) in the very preterm/VLBW population (OR 2.27, 95% confidence interval 1.15–4.47). The overall prevalences were 9.9% in the very preterm/VLBW group and 5.5% in the comparison group. Interpretation Those born very preterm/VLBW have an increased risk of developing clinically significant anxiety problems in adolescence.