Immunological abnormalities in patients with untreated retinal vasculitis.

Peripheral blood immunological features were assessed in 21 patients with clinical and angiographic evidence of retinal vasculitis (RV). Abnormalities of humoral and cellular immunity were frequent in this group of patients. Lymphopenia was the most common immunological abnormality, being present in 76% of patients at presentation (p less than 0.05). Peripheral blood T and B cells were decreased with a normal helper (OKT4) to suppressor (OKT8) T cell ratio in 11 patients tested (five with Behçet''s syndrome and six with idiopathic RV). Significantly increased concentrations of serum immune complexes were present in 55% of patients (p less than 0.05). Results of the present study indicate the frequent association of peripheral blood immunological abnormalities in patients with active RV and indicate the possible role of immunological mechanisms in its pathogenesis.     

Decreased vagal power during treadmill walking in patients with chronic fatigue syndrome

The purpose of this study was to determine if patients with the chronic fatigue syndrome have less vagal power during walking and rest periods following walking, in comparison to a group of healthy controls. Eleven patients (ten women and one man) who fulfilled the case definition for chronic fatigue syndrome modified to reduce heterogeneity and eleven healthy, but sedentary, age- and sex-matched controls walked on a treadmill at 2.5 mph four times each for 4 min duration. Between each period of walking, subjects were given a 4-min seated rest period. Vagal power, a Fourier-based measure of cardiac, parasympathetic activity in the frequency range of 0.15 to 1.0 Hz, was computed. In each period of walking and in one period of rest, patients had significantly less vagal power than the control subjects despite there being no significant group-wise differences in mean heart rate, tidal volume, minute volume, respiratory rate, oxygen consumption or total spectrum power. Further, patients had a significant decline in resting vagal power after periods of walking. These results suggest a subtle abnormality in vagal activity to the heart in patients with the chronic fatigue syndrome and may explain, in part, their post-exertional symptom exacerbation.     

A possible drug interaction between rifampicin and enalapril

Summary When a 35-year-old man with essential hypertension was treated with antibiotics for brucellosis his blood pressure rose significantly. While all other treatment was kept constant rifampicin was discontinued. On rechallenge rifampicin did not alter serum concentrations of enalapril or the area under the curve (AUC) between 0 and 7 h, but it did reduce the AUC of the active metabolite enalaprilat by 31%. These observations suggest that there may be an interaction between rifampicin and enalapril, causing reduced hypotensive efficacy of enalapril. The mechanism of such an interaction merits further study, but it could be due to enhanced renal clearance of enalaprilat.     

Improved ankle function in children with cerebral palsy after computer-assisted motor learning

The effect of biofeedback training on ankle function was studied in young children with cerebral palsy (CP) during a pilot study and a 6-week follow-up study. Patients underwent range of motion (ROM) and ankle dorsiflexor (DF) strength training in a laboratory 3 days per week, receiving auditory and visual feedback. An at-home programme used portable EMG units to help train DF muscle recruitment on the remaining days. Independent outcome measures included DF strength, active ROM. and tapping ability pretraining and 6 weeks and 14 months posttraining. Tapping ability increased significantly in the trained leg posttraining. It then fell significantly at the 6-weeks posttraining test, but remained significantly higher than pretest levels, and returned to pretraining levels by 14 months. Passive ROM was unchanged, but active ROM increased significantly in the trained leg. DF strength increased in most children posttraining in both the pilot and main study. Increased motor-unit recruitment is believed to explain the increases in DF strength and active ROM. These results suggest that biofeedback training can improve ankle function, and the implications for gait are discussed.     

An analysis of the biomechanical mechanism of tibial stress fractures among Israeli infantry recruits. A prospective study

The biomechanical mechanism of tibial diaphyseal stress fractures was studied prospectively in a group of 286 Israeli recruits. Before training each recruit had roentgenograms taken of his tibiae. Measurements of total tibial and cortical widths in the anteroposterior (AP) and mediolateral planes were made on these roentgenograms at two levels: at the point of the narrowest tibial width on AP roentgenograms (Level 1) and at the point of the narrowest width on lateral roentgenograms (Level 2). The tibial cross section was idealized as an eccentric ellipse within an ellipse, and on the basis of measurements taken from the roentgenograms, the cross-sectional area (compression strength), area moments of inertia about AP and mediolateral axes of bending (bending strength), and the area polar moment of inertia (torsional strength) were calculated for each cross section. During the course of 14 weeks of training, 20% of the recruits sustained tibial diaphyseal stress fractures, all of which were along the medial cortex. Using stepwise logistic regression analysis the tibia's bending strength along an AP axis of bedding at Level 2 was found to be the most significant factor determining whether or not a recruit would develop a tibial stress fracture.     

Characterization of novel phorbol ester- and serum-responsive sequences of the rat ornithine decarboxylase gene promoter

Ornithine decarboxylase (a), the key regulatory enzyme in mammalian polyamine biosynthesis, is rapidly induced by mitogens and tumor promoters. We used transient expression assays and DNA-protein binding studies to examine the regulation of ODC promoter activity by phorbol esters and serum growth factors. A fragment of the ODC 5′ flanking region (nt -1156 to + 13) was sufficient to confer 12-O-tetradecanoylphorbol-13-acetate (a) -responsive expression to a luciferase reporter gene when transfected into H35 cells. However, induction by TPA was not observed in Rat2 fibroblasts, although refeeding of serum-starved Rat2 cells with fresh serum-containing medium rapidly induced a fivefold to sixfold increase in ODC promoter activity, maximal about 8 h after refeeding. Deletion analysis demonstrated that several sequences contributed to basal ODC promoter activity but that nt -92 to +13 was sufficient for induction by TPA or by serum. This sequence lacked canonical TPA-responsive elements, and an activator protein-1 (AP-1) consensus oligonucleotide failed to compete effectively for proteins binding to this region. Two of four protein complexes observed by gel-shift analysis of nt -92 to +13 were competitively inhibited by wild-type but not mutant oligonucleotides encompassing a variant cyclic AMP-response element (a) (ODC nt -50 to -42); however, a consensus CRE did not compete. Mutagenesis of this site demonstrated that it contributes to basal expression of the ODC promoter but not to TPA or serum responsiveness. Thus, we conclude that the proximal ODC promoter (nt -92 to +13) responds to TPA and serum stimulation in a cell-type-specific manner that is not mediated by canonical AP-1 elements. © 1995 Wiley- Liss, Inc.     

Uveitis: aetiology and disease associations in an Australian population

Over a five-year period 245 patients with uveitis were investigated at the Uveitis Clinic, Sydney Eye Hospital, for possible aetiological and relevant disease associations. Uveitis was anterior in 75% of patients, posterior in 21% and generalized in 4%. Anterior uveitis (AU) was idiopathic in 52% of cases. In patients tested for the HLA-B27 antigen, 47% were HLA-B27 positive, including all cases of ankylosing spondylitis (8% of cases) and Reiter's syndrome (3% of cases). There was a marked male predominance in patients with AU, especially in HLA-B27 positive individuals. Posterior uveitis (PU) was most frequently unilateral, chronic and idiopathic (24% of cases), whilst recognizable aetiologies included toxoplasmosis (20%), Behcet's syndrome (14%), sarcoidosis (12%) and pars planitis (12%). The peak age of onset in patients presenting with AU was 30 to 40 years, whilst patients with PU presented a decade earlier. There were no major differences between males and females in the age of onset of their uveitis.