Ascent of the testis in children

Among 460 children who had an orchiopexy (ORP), we identified 72 children who had attended our institution 1-12 years earlier and in whom the testicular position had been specified. Of the 72 boys 19 were had ascended testes (26%). The age at ORP of the children with ascent of the testes was 7.0 years (1.8-14.0 years). Light and electron microscopy of 13 testicular biopsies taken at ORP, showed alterations of germ cells and Sertoli cells, similar but less pronounced than alterations seen in congenital undescended testes. Conclusion. A normally positioned testis may ascend into the inguinal region or upper scrotum and remain there fixed. This secondary cryptorchidism does not usually respond to human chorionic gonadotropin treatment and must be corrected by orchiopexy.     

A meta-analysis of studies concerning the safety effects of daytime running lights on cars

A meta-analysis of 17 studies that have evaluated the effects on traffic safety of using daytime running lights (DRL) on cars is presented. A distinction is made between studies that have evaluated the effects of DRL on the accident rates of each car using it and studies that have evaluated changes in the total number of accidents in a country following the introduction of mandatory use of DRL. Three different definitions of the measure of safety effects are compared and their validity discussed. It is concluded that the use of DRL on cars reduces the number of multi-party daytime accidents by about 10–15% for cars using DRL. The estimated effects on the total number of accidents of introducing DRL laws are somewhat smaller, 3–12% reduction in multi-party daytime accidents, and are likely to contain uncontrolled confounding effects. There is no evidence to indicate that DRL affects types of accident other than multi-party daytime accidents.     

Major histocompatibility complex class II-dependent antigen presentation by human intestinal endothelial cells

BACKGROUND & AIMS: In the normal gut, human intestinal microvascular endothelial cells (HIMECs) express major histocompatibility complex (MHC) class II molecules. Enhanced expression is found in chronic inflammation. We examined the cytokine regulation of MHC class II molecules and the associated invariant chain (Ii) in HIMECs and investigated whether such cells can process and present a complex protein antigen to T cells. METHODS: Enzyme-linked immunosorbent assay, flow cytometry, immunoelectron microscopy, as well as T-cell activation assay with HIMECs and HLA-DR-restricted T-cell clones were employed. RESULTS: In unstimulated HIMEC monolayers, HLA-DR, -DP, and -DQ and Ii were undetectable at the protein level, but interferon gamma (IFN-gamma) (100 U/mL) induced expression that peaked for DR after 2-3 days, for DP after 4-6 days, for DQ after 10-12 days, and for Ii after 2-3 days. Tumor necrosis factor alpha had no effect alone but enhanced class II expression in combination with IFN-gamma, most notably for DQ and DP. HLA-DR3-restricted and Mycobacterium tuberculosis heat shock 65-kilodalton-specific T-cell clones were activated to produce IFN-gamma in response to relevant antigen presented by IFN-gamma-treated HIMECs. This response was inhibited by blocking monoclonal antibody to HLA-DR and by chloroquine when compared to professional antigen-presenting cells, HIMECs activated T-cell clones quite efficiently. CONCLUSIONS: These data suggest that microvascular endothelial cells can present complex protein antigens in the human gut.     

Enhancing hydrolysis with microaeration.

Effects of microaeration on hydrolysis of primary sludge are investigated in 500 ml batch reactors at 377 degrees C. Two experiments, one with a microaerobic inoculum and one with a combination of a microaerobic and an anaerobic inoculum, are carried out to also investigate the role of the inoculum. Assuming an acidogenic, methanogenic and aerobic biomass yield of 0.1, 0.05 and 0.45 mgC/mgC, respectively, a 50-60% hydrolysis increase, during the 4 day experiment, is observed with a ratio between aerobic and anaerobic metabolism in the range 0.5-0.7. The extra hydrolysed products are oxidized to carbon dioxide and incorporated into new biomass. The oxygen utilization to carbon dioxide production ratio was - 1:1 on a mol basis. Effects of the oxygen supplied on the hydrolysis of carbohydrates, proteins and lipids are analyzed based on measurements and balances of dissolved carbon, nitrogen and COD. The total observed hydrolysis increase can be accounted for by increased hydrolysis of carbohydrates and proteins. Lipids are only hydrolysed when anaerobic inoculum is added, but no effect of oxygen availability is detected.     

ADM1 simulations of hydrogen production.

Hydrogen can be produced by fermentation of organic wastes as a renewable CO2 emission free fuel. The production potential as a function of feed composition is investigated using the ADM1 and experimental data from the literature. Lactate and ethanol are included in the model as intermediates to simulate the bio-hydrogen production processes more closely. Simulated effects of carbohydrate to protein ratio in the feed on pH, H2, biomass and fatty acid production using standard model parameters compare quite well with experimental results. The overall hydrogen and biomass production corresponds well with measurements for some feeds and less for others. The maximum theoretical yield is significantly higher than the simulated and measured values and is highest when the feed consists of only carbohydrates. The analysis suggests that the modified ADM1 is capable of simulating the main mechanisms involved in biological hydrogen production processes, implying that the model can be used to identify, and find strategies to influence limiting factors in bio-hydrogen production processes. Model weaknesses regarding the acidogenesis processes are observed and areas for further improvements discussed.     

Applicability of the single-breath carbon monoxide diffusing capacity in a Norwegian Community Study

The test of single-breath diffusing capacity for carbon monoxide (DLCO) has been widely used in population surveys. However, little is known about the effect of meeting or failing to meet the criteria for acceptability of this test. The American Thoracic Society (ATS) recommends a breathholding time of 9 to 11 s, two measurements within +/- 10% or 3 ml CO(STPD)/min/mm Hg of the average DLCO, and an inspiratory vital capacity (IVC) of at least 90% of the largest previously measured forced vital capacity (FVC) as criteria for this test. The objective of the present study was to examine the extent to which these criteria were met in a community study. To do this, a random sample of 3,740 persons, aged 15 to 70 yr, of the general population of the city of Bergen and 11 surrounding municipalities on the southwest coast of Norway were enrolled in a two-phase cross-sectional study. In the second phase, a stratified sample (n = 1,512) of the respondents to the postal questionnaire used for recruitment for the study (n = 3,370) were invited to a clinical and respiratory physiologic examination that included the DLCO test. The attendance rate was 84% (1,275 of 1,512). In the examination, all subjects were able to maintain a breathholding time of 9 to 11 s, and 98% had two DLCO values within +/- 10% or 3 ml CO(STPD)/min/mm Hg of the average DLCO. The criterion of an IVC of at least 90% of FVC in the two tests was met by 68% of the subjects. Younger age was an independent predictor of failure to meet the required criteria. Thus, only two-thirds of the participants fulfilled all of the ATS criteria for the DLCO test, the main reason for failure being an IVC of less than 90% FVC. This should not necessarily lead to the exclusion from further analysis of those failing to meet this criterion.     

Fracture mechanical Markov chain crack growth model

On the basis of the B-model developed in [J. L. Bogdanoff and F. Kozin, Probabilistic Models of Cumulative Damage. John Wiley, New York (1985)] a new numerical model incorporating the physical knowledge of fatigue crack propagation is developed. The model is based on the assumption that the crack propagation process can be described by a discrete space Markov theory. The model is applicable to deterministic as well as to random loading. Once the model parameters for a given material have been determined, the results can be used for any structure as soon as the geometrical function is known.     

Symptoms, complaints, ocular and nasal physiological signs in university staff in relation to indoor environment - temperature and gender interactions

Symptoms, signs, perceptions, and objective measures were studied in university buildings. Two problem buildings with a history of dampness and complaints were compared with two control buildings. Health investigations among university staff were performed at the workplace (n = 173) including tear film stability [non-invasive break-up time (NIBUT) and self-reported break-up time (SBUT)], nasal patency (acoustic rhinometry), nasal lavage fluid analysis [NAL: eosinophil cationic protein (ECP), myeloperoxidase (MPO), lysozyme and albumin] and atopy by total serum IgE and IgE antibodies (Phadiatop). Exposure assessment included inspections, thermal and atmospheric climate at 56 points modelled for all work sites. Multiple regressions were applied, controlling for age and gender. Exposure differences between problem buildings and controls were small, and variations between rooms were greater. Workers in the problem buildings had more general and dermal symptoms, but not more objective signs than the others. Adjusted day NIBUT and SBUT increased at higher night air temperatures, with B (95% CI) 0.6 (0.04-1.2) and 1.3 (-0.02 to 2.5), respectively. Higher relative humidity at mean day air temperature <22.1 degrees C was associated with adjusted NIBUT and SBUT, with B (95% CI) 0.16 (0.03-0.29) and 0.37 (-0.01 to 0.75), respectively. Air velocity below recommended winter values and reduced relative humidity in the range of 15-30% were associated with dry air and too low temperature. PRACTICAL IMPLICATIONS: Thermal climate in university buildings may be associated with both perceptions and physiological signs. Reduced night time air temperature, increased difference in air temperature between day and night, and fast changes in air temperature might impair indoor environment. This may have implication for energy-saving policies. It might be difficult to identify the exposure behind, and find the reason why, some buildings are defined as 'problem buildings'.