Distribution of the interleukin-8 receptors, CXCR1 and CXCR2, in inflamed gut tissue

There is increasing evidence to suggest that the potent neutrophil chemoattractant interleukin-8 (IL-8) has an important role in the pathogenesis of inflammatory bowel disease. IL-8 mediates its actions via two cell surface receptors, CXCR1 and CXCR2. This paper describes the distribution of these IL-8 receptors in the normal gastrointestinal tract and how this is modified in ulcerative colitis (UC). Paraffin-embedded colonic resection specimens were stained with monoclonal antibodies directed against CXCR1 and CXCR2 in ten cases of total UC, 16 cases of appendicitis, and 11 histologically normal sections. A semiquantitative scale of 0-4 was used to assess the proportion and intensity of positively stained cells within certain defined areas of tissue. A comparative assessment was made of the distribution of various cell populations. Dual immunostaining was used to confirm the phenotype of positively staining cells. In the histologically normal colon, the antibody against CXCR1 stained a subpopulation of macrophages deep to the epithelium and germinal centre lymphocytes. A similar pattern of staining was seen in acute appendicitis, with in addition some positively stained neutrophil polymorphs. In UC, there was up-regulation of CXCR1, with a striking increase in positively stained macrophages throughout the mucosa and of B and T lymphocytes outside the germinal centre areas. There was also intense up-regulation of CXCR1 expression by the luminal epithelium, reflected in the epithelial staining score (mean+/-SE=1.8+/-0.44 for UC cases, vs. 0.23+/-0.16 for controls and 0.25+/-0.14 for acute appendicitis). CXCR2 was only expressed on a small population of lamina propria mononuclear cells and crypt epithelial cells, with no significant differences observed between the groups. These results suggest that IL-8 may, through CXCR1, have a role beyond neutrophil recruitment in mediating the immune response in UC and that this is not merely a consequence of the acute inflammation seen in UC.

Distribution of the interleukin-8 receptors, CXCR1 and CXCR2, in inflamed gut tissue

There is increasing evidence to suggest that the potent neutrophil chemoattractant interleukin-8 (IL-8) has an important role in the pathogenesis of inflammatory bowel disease. IL-8 mediates its actions via two cell surface receptors, CXCR1 and CXCR2. This paper describes the distribution of these IL-8 receptors in the normal gastrointestinal tract and how this is modified in ulcerative colitis (UC). Paraffin-embedded colonic resection specimens were stained with monoclonal antibodies directed against CXCR1 and CXCR2 in ten cases of total UC, 16 cases of appendicitis, and 11 histologically normal sections. A semiquantitative scale of 0-4 was used to assess the proportion and intensity of positively stained cells within certain defined areas of tissue. A comparative assessment was made of the distribution of various cell populations. Dual immunostaining was used to confirm the phenotype of positively staining cells. In the histologically normal colon, the antibody against CXCR1 stained a subpopulation of macrophages deep to the epithelium and germinal centre lymphocytes. A similar pattern of staining was seen in acute appendicitis, with in addition some positively stained neutrophil polymorphs. In UC, there was up-regulation of CXCR1, with a striking increase in positively stained macrophages throughout the mucosa and of B and T lymphocytes outside the germinal centre areas. There was also intense up-regulation of CXCR1 expression by the luminal epithelium, reflected in the epithelial staining score (mean+/-SE=1.8+/-0.44 for UC cases, vs. 0.23+/-0.16 for controls and 0.25+/-0.14 for acute appendicitis). CXCR2 was only expressed on a small population of lamina propria mononuclear cells and crypt epithelial cells, with no significant differences observed between the groups. These results suggest that IL-8 may, through CXCR1, have a role beyond neutrophil recruitment in mediating the immune response in UC and that this is not merely a consequence of the acute inflammation seen in UC.

Physiologically based pharmacokinetics and the dermal absorption of 2-butoxyethanol vapor by humans

It has generally been assumed that the skin contributes only minor amounts to the total uptake of solvent vapors, relative to the respiratory tract. Contrary to this assumption, the widely used glycol ether solvent, 2-butoxyethanol (BE), has been reported to be more effectively absorbed through the skin (75% of the total uptake) than through the lungs of humans (Johanson and Boman, 1991, Br. J. Ind. Med. 48, 788). The possibility that the finger prick blood sampling technique used in the Johanson and Boman study was confounded by locally high concentrations of BE at the site of absorption was suggested using a previously developed PBPK model (Corley et al., 1994, Toxicol. Appl. Pharmacol. 129, 61). The current study was conducted to verify the PBPK analysis and to determine whether or not the skin was the major site for absorption of BE vapor by exposing one arm from each of six human volunteers to 50 ppm 13C2-BE vapor for 2 hr. To evaluate the potential consequences of blood sampling techniques, samples were taken from both the unexposed arm (catheter; during and after exposure) and the exposed arm (finger prick; end of the exposure only) for analysis of both BE and its major metabolite, butoxyacetic acid (BAA). Butoxyacetic acid is responsible for the hemolysis observed in toxicity studies with laboratory animals. Humans, however, are significantly less sensitive to this effect. The concentration of BE in the finger prick blood samples averaged 1500 times higher than the corresponding concentration in venous blood sampled from a catheter installed in the unexposed arm at the end of the exposure. Blood BAA levels were generally within a factor of 4 of each other for the two techniques and, therefore, was considered a better indicator of systemic absorption. Urine was collected for 24 hr and analyzed for the following metabolites found in rat metabolism studies: free and conjugated BE, BAA, ethylene glycol (EG), and glycolic acid (GA), with only BAA detected in the human urine. More importantly, urinary BAA was found to be extensively conjugated ( approximately 67%) with glutamine, confirming recent reports. These results, coupled with PBPK modeling of worst-case exposure scenarios (no clothing, 100% of the body was exposed), demonstrated that no more than 15-27% (low-to-high relative temperatures and humidities), not 75%, of the total uptake of BE could be attributed to the skin of humans during simulated 8-hr exposures to the ACGIH TLV concentration of 25 ppm. Even less of the total uptake was attributed to the skin during simulations of exercise with whole-body exposures (5-9%) or by more realistic exposures of only the arms and head (1-8%). As a result, humans are unlikely to reach hemolytic concentrations of the metabolite BAA in blood following vapor exposures to BE.

A mobile rehabilitation team program to assist patients in nursing homes rehabilitate and return to their homes

A slow-stream rehabilitation program for frail elderly patients was developed utilising nursing homes visited by a mobile rehabilitation team (MRT) based at the hospital from which these patients had been discharged following major illness. The nursing homes were able to provide physiotherapy and the MRT contributed medical, nursing, occupational therapy and social work support through weekly visits. The supported group and a control group (also discharged to nursing homes from the same hospital but unsupported) were matched for age, sex and ADL level. Outcomes for the two groups were compared and were significantly different. Of the supported group (N = 33), 64% (N = 21) were discharged home compared with only 9% (N = 2) of the 23 control subjects (chi2 = 15.6, df. = 1, P < 0.05). The potential for patient rehabilitation in a modestly supported nursing home was realised.

Inhalation toxicity of aerosolized pentamidine isethionate in rats and dogs

The toxicity of inhaled aerosolized pentamidine isethionate solutions in rats and dogs was evaluated. Nose-only exposure equipment and a mass mean aerodynamic particle size of < or = 2 microns were employed. Rats received either a single inhaled dose estimated at 0, 1.4, 2.1, or 6.0 mg/kg/exposure day or 4 inhaled doses evenly spaced over 13 weeks estimated at 0, 0.35, 0.7, or 1.4 mg/kg/exposure day. Dogs were administered a single inhaled dose estimated at 0, 1.1, 3.4, or 5.0 mg/kg/exposure day. Rats administered a single inhaled dose of 6.0 mg/kg/exposure day exhibited respiratory distress. The lung-with-trachea weights of these animals were elevated relative to controls. The histopathology of acutely exposed rats consisted of dose-related neutrophil infiltration in the turbinates, larynx, and bronchi; erosion of epithelium in the turbinates and larynx; thickening of the alveoli walls with alveolar accumulation of mononuclear cells and neutrophils; and rhinitis. Rats in the highest dose group in the subchronic evaluation exhibited decreased body weight gains and reduced lung-with-trachea-to-body weight ratios relative to controls. Hematology, clinical chemistry, and urinalysis values were within normal ranges. Microscopic pulmonary tissue changes were similar to those found in acute exposure with certain lesions (e.g., mucous cell hyperplasia) suggestive of a more chronic process. In addition, lung fibrosis was seen at the highest dose. In dogs, pentamidine isethionate did not cause a change in the respiratory minute volume (not measured in rats). Elevated lung-with-trachea weights were noted in the high- dose females. Hematology, clinical chemistry, and urinalysis values were within normal ranges.(ABSTRACT TRUNCATED AT 250 WORDS)

An epidemiological and clinical investigation of pulmonary function and respiratory symptoms in patients with rheumatoid arthritis

Several studies have investigated lung function in patients with rheumatoid arthritis but have reached different conclusions. The main discrepancy has been between airways disease reported in 38-65 per cent of patients and interstitial pulmonary disease reported in 30-41 per cent. These variable results have probably arisen because specific lung disorders have often been diagnosed on the basis of non-specific tests of lung function which, when considered in isolation, are subject to different interpretations. We adopted a combined epidemiological and clinical approach to investigate lung function and respiratory symptoms in patients with rheumatoid arthritis. Epidemiological data showed that rheumatoid arthritis is associated with a mild restrictive lung defect with reductions in mean FEV1 and FVC of 0.26 l and 0.29 l respectively and a normal FEV1/FVC ratio. The reduction in mean maximum mid-expiratory flow rate of 0.34 l/s could be explained on the basis of lung restriction and there was no evidence of widespread airways dysfunction other than that which could be explained by cigarette smoking. The clinical study showed that abnormal lung function tests in individual patients were caused by a heterogeneous group of conditions which are frequently caused, or exacerbated, by cigarette smoking. Cigarette smoking, and not the rheumatoid process, was the most frequent cause of abnormal lung function in rheumatoid arthritis.

Thiram-induced toxic liver injury in male Sprague-Dawley rats

A single i.p. dose (120 mg/kg) of thiram given to male Sprague-Dawley rats caused a significant increase in the activity of SGOT and SGPT 24 hr post-treatment indicating liver damage. A considerable diminution in the serum cholinesterase activity was also noted in the treated rats as against the control animals. Additional evidence for thiram-induced liver toxicity is provided by the observation that there was approximately 50% inhibition of the activity of hepatic microsomal benzphetamine N-demethylase with a concomitant decrease in the concentration of cytochrome P-450, an important component of the mixed-function oxidase system. Although not significant, hepatic glutathione levels were also depleted by thiram, probably making the liver susceptible to toxic injury.