Tissue interleukin 1 and interleukin-1 receptor antagonist expression in enterocolitis in resistant and susceptible rats

BACKGROUND/AIMS: Subserosal injection of purified group A streptococcal peptidoglycan-polysaccharide (PG-APS) induces chronic relapsing granulomatous enterocolitis and systemic inflammation in susceptible inbred Lewis rats but only transient intestinal injury in Buffalo and Fischer rats. Cecal interleukin 1 (IL-1) and IL-1 receptor antagonist (IL-1ra) expression was measured in inbred rats displaying differential susceptibility to experimental enterocolitis. METHODS: The ileum and cecum of Lewis, Buffalo, and Fischer rats were subserosally injected with purified PG-APS or albumin. IL-1 and IL-1ra messenger RNA (mRNA) and protein (IL-1 only) were measured 1 or 27 days later. PG-APS-injected Lewis rats were treated with recombinant human IL-1ra. Kinetics of IL-1 and IL-1ra mRNA expression were studied in peritoneal cells. RESULTS: All rats strains developed acute inflammation with increased cecal concentrations of IL-1 beta and IL-1ra mRNA. Lewis rats developed chronic enterocolitis and had higher IL-1 and IL-1ra mRNA tissue levels than Buffalo or Fischer rats, which displayed no chronic inflammation. IL-1 beta and IL-1ra were produced by submucosal granulomas and correlated with inflammation. IL-1 alpha protein levels paralleled IL-1 beta mRNA expression. IL-1ra treatment attenuated acute and chronic enterocolitis, adhesions, and arthritis. PG-APS induced IL-1 and IL-1ra expression in peritoneal cells from Lewis and Fischer rats. CONCLUSIONS: Bacterial cell wall polymers stimulate IL-1 and IL-1ra expression in vivo and in vitro. These counterbalancing cytokines are increased in experimental enterocolitis and have important immunoregulatory roles in intestinal inflammation.     

Laboratory diagnosis of keratomycosis: comparative evaluation of direct microscopy and culture results

We have studied the variation of lateral diffusion of proteins in the cell membrane, of membrane lipid fluidity and of the electrophoretic motility (EPM) of macrophages after treatment with extrinsic laminin. The results showed that the lateral diffusion coefficient D value of membrane proteins, the fluidity of membrane lipids and the EPM of macrophages were decreased after laminin had bound to its membrane receptor on the macrophages. These results are important for developing an understanding of the early reaction of plasma membranes and cells in the presence of laminin.     

Interleukin-1 receptor antagonist decreases bone loss and bone resorption in ovariectomized rats

Interleukin-1 (IL-1), a cytokine produced by bone marrow cells and bone cells, has been implicated in the pathogenesis of postmenopausal osteoporosis because of its potent stimulatory effects on bone resorption in vitro and in vivo. To investigate whether IL-1 plays a direct causal role in post ovariectomy bone loss, 6-mo-old ovariectomized rats were treated with subcutaneous infusions of IL-1 receptor antagonist (IL-1ra), a specific competitor of IL-1, for 4 wk, beginning either at the time of surgery or 4 wk after ovariectomy. The bone density of the distal femur was measured non invasively by dual-energy X-ray absorptiometry. Bone turnover was assessed by bone histomorphometry and by measuring serum osteocalcin, a marker of bone formation, and the urinary excretion of pyridinoline cross-links, a marker of bone resorption. Ovariectomy caused a rapid increase in bone turnover and a marked decrease in bone density which were blocked by treatment with 17 beta estradiol. Ovariectomy also increased the production of IL-1 from cultured bone marrow cells. Ovariectomy induced-bone loss was significantly decreased by IL-1ra treatment started at the time of ovariectomy and completely blocked by IL-1ra treatment begun 4 wk after ovariectomy. In both studies IL-1ra also decreased bone resorption in a manner similar to estrogen, while it had no effect on bone formation. In contrast, treatment with IL-1ra had no effect on the bone density and the bone turnover of sham-operated rats, indicating that IL-1ra specifically blocked estrogen-dependent bone loss. In conclusion, these data indicate that IL-1, or mediators induced by IL-1, play an important causal role in the mechanism by which ovariectomy induces bone loss in rats, especially following the immediate post ovariectomy period.     

Information processing by school-age children with specific language impairment: evidence from a modality effect paradigm

School-age children with specific language impairment (SLI) and age-matched controls were tested for immediate recall of digits presented visually, auditorily, or audiovisually. Recall tasks compared speaking and pointing response modalities. Each participant was tested at a level that was consistent with her or his auditory short-term memory span. Traditional effects of primacy, recency, and modality (an auditory recall advantage) were obtained for both groups. The groups performed similarly when audiovisual stimuli were paired with a spoken response, but children with SLI had smaller recency effects together with an unusually poor recall when visually presented items were paired with a pointing response. Such results cannot be explained on the basis of an auditory or speech deficit per se, and suggest that children with SLI have difficulty either retaining or using phonological codes, or both, during tasks that require multiple mental operations. Capacity limitations, involving the rapid decay of phonological representations and/or performance limitations related to the use of less demanding and less effective coding and retrieval strategies, could have contributed to the working memory deficiencies in the children with SLI.     

Spine fractures in active duty soldiers and their return to duty rate

To evaluate the outcome of thoracolumbar spine fractures in active duty soldiers, we conducted a retrospective review of 23 soldiers followed at a single institution. Twenty-two charts were available for review. The average age was 31.9 years (range, 19-49 years), and the average follow-up was 3.6 years (range, 2-11 years). There were 20 males and 2 females. All injuries except one occurred between 1990 and 1994, and all were treated by a single surgeon. We attempted to correlate five independent variables with regard to whether the patient returned to his or her previous duty or was required to undergo a medical evaluation board to determine fitness for duty. The variables included military rank, physical job demands, fracture type, initial neurological status, and initial treatment (operative versus nonoperative). Fourteen of the 22 soldiers (64%) underwent medical evaluation boards, whereas 8 (36%) returned to their previous duties. We found a strong correlation between increasing military rank and return to preinjury duties. As expected, physical job demands correlated strongly with eventual disposition, in that soldiers in jobs with low physical demands were more likely to be retained on active duty in their present position. Neurologic status (except motor deficit), type of fracture (except fracture-dislocation), and initial treatment did not correlate well with eventual disposition.