Respiratory health status in swine producers using respiratory protective devices

A cross-sectional survey on respiratory health in swine producers showed that 30% of 301 examined men usually used a dust mask when working inside a barn. They did not differ significantly from dust mask nonusers in respect to respiratory symptoms and lung function. This analysis was undertaken to determine whether the respiratory health of dust mask users was associated with reasons why they had started individual respiratory protection. The subjects were recontacted in order to identify those who started using a mask to deliberately prevent symptoms (42 men) and those who started protection because of pre-existing respiratory symptoms (44 men). Not unexpectedly, betweengroup comparisons of respiratory symptoms and lung function suggest that swine producers who wear dust masks for preventive purposes have better respiratory health than those who wear dust masks because of symptoms or those who do not use individual respiratory protection. The individual reasons for starting dust mask usage should be examined among potential determinants of the outcomes of prospective studies which can then provide more valid assessment of the effect of individual respiratory protection. © 1993 Wiley-Liss, Inc.     

Non-secretion of ABO blood group antigens as a host susceptibility factor in the spondyloarthropathies

Gram negative bacteria precipitate reactive arthritis and may be concerned in the pathogenesis of ankylosing spondylitis and other spondyloarthropathies. Susceptibility to many infectious agents is associated with ABO blood group or secretor state, or both. The distribution of the ABO blood group or secretor state, or both, was therefore determined in 87 patients with ankylosing spondylitis and 32 with other forms of spondyloarthropathy. The prevalence of non-secretors was significantly increased in the total patient group (54/114; 47%) and in the subgroup with ankylosing spondylitis (41/84; 49%) compared with local controls (89/334; 27%) (p less than 0.001). Other subgroups of patients showed a similarly increased prevalence of non-secretion (33-47%). The distribution of ABO blood groups did not differ between patients and controls. The association between non-secretor state and ankylosing spondylitis strengthens the hypothesis that ankylosing spondylitis is a form of reactive arthritis. It also suggests several pathogenic mechanisms which may be relevant to the initial hostparasite interaction in ankylosing spondylitis.     

Functional and structural characteristics of the glycosaminoglycans of the bladder luminal surface

The glycosaminoglycan layer of bladder has been proposed to play a crucial role in protecting the bladder from harmful substances in urine. Rats were partially cystectomized to determine whether bladder glycosaminoglycans are routinely eluted from the bladder surface in detectable quantities. Cystectomy produced no detectable qualitative or quantitative changes in excreted GAG thereby showing that most urinary glycosaminoglycan originates in the kidney and not from the bladder. Damaging the glycosaminoglycan layer by a dilute acid wash, however, leads to a consistent decrease in the output of urinary GAG which recovers to normal at the same rate as the layer regenerates. This suggests that the newly exposed sites tightly bind urinary GAG. We suggest that such binding may be a component of the normal physiological defense mechanism of the bladder. The bladder glycosaminoglycan layer was isolated, dilute acid being used to elute ionically-bound material and brief trypsinization to elute intercalated proteoglycans from the luminal surface. The GAG from the luminal surface, which was present at a density of one chain per 50 nm.2 of bladder surface, was quite different in composition from that isolated from the whole bladder.     

Use of superparamagnetic contrast media to suppress signal from flowing spins: Preliminary experience

The authors describe their preliminary experience with the use of superparamagnetic magnetic resonance (MR) imaging contrast media for suppression of signal from flowing blood. The goal of this work was to determine if a superparamagnetic contrast agent could successfully eliminate blood signal during cardiac-gated MR imaging, thereby eliminating or reducing flow artifacts associated with the complex and variable hemodynamics within the heart chambers. Imaging and data analysis were performed in 17 dogs subjected to experimental myocardial infarction as part of a parallel project. Six doses (0.2, 1, 2, 3.5, 4, 5, and 10 mg/kg) of AMI-25, an experimental contrast agent, were used in the study. Spin-echo imaging was performed immediately before and every 5 minutes (for an average of 25 minutes) after bolus injection of the contrast agent. Variations in the image signal-to-noise ratio relative to a baseline (before injection of contrast agent) image were assessed as a function of dose and time. Preliminary results suggest that a considerable reduction in blood flow artifacts and, hence, increases in image signal-tonoise ratio can be achieved at doses greater than or equal to 3.5 mg/kg, for approximately 20 minutes after injection. Doses equal to or less than 2 mg/kg and images obtained more than 20 minutes after injection (regardless of dose) did not reliably show hemodynamic artifact suppression.     

Pre-operative assessment of anal fistulas using endoanal ultrasound

Objective To study the accuracy of endoanal ultrasound in pre‐operative assessment of cryptoglandular anal fistulas, with respect to the site of the internal opening, type and depth of the fistula tract. Patients and methods A consecutive series of 151 patients with anal sepsis underwent pre‐operative endoanal ultrasound assessment of a suspected anal fistula. Hydrogen peroxide was used to define the tract when there was doubt as to the course of the fistula. All patients subsequently had surgical exploration under anaesthesia, irrespective of findings at sonography. The site of the internal opening, depth and type of fistula were recorded at surgery, and concordance with the ultrasound was assessed. Results One hundred and forty‐five patients were subsequently shown to have a fistula at surgical exploration. Type of fistula: Two thirds were transsphincteric (63%) and one third were inter sphincteric (32%), with a few submucosal, and supra sphincteric fistulas. Ultrasound correctly predicted surgical findings in 82% of patients (124/151). Concordance was highest for transsphincteric fistulas (87%). Internal opening: Accuracy of predicting the site of the internal opening was 93% (140/151). The commonest site for the internal opening was the midline posteriorly (49%), followed by the midline anteriorly (25%), the rest lay laterally. Fistula depth: Ultrasound and surgical assessment of the depth of fistulas was concordant in 120 of 145 patients (83%). Conclusions Endoanal ultrasound has a high accuracy of predicting the site of internal opening of an anal fistula. Endoanal ultrasound is able to assess the type and depth of a fistula. This information is useful for pre‐operative planning of fistula treatment.