The duration and amplitude of the plateau phase of ATP- and ADP-evoked Ca(2+) signals are modulated by ectonucleotidases in in situ endothelial cells of rat aorta

ATP has a long-lasting vasodilatory effect, possibly due to its capability to induce a prolonged increase in the intracellular Ca(2+) concentration ([Ca(2+)](i)) in endothelial cells (EC) and activate constitutive nitric oxide synthase. However, contradictory data have been reported regarding the time course of ATP-evoked Ca(2+) signals in in situ EC. In particular, short-duration Ca(2+) signals have been reported, which might be thought to be unable to sustain a prolonged, NO-induced vasodilation. The current experiments were therefore performed in in situ EC of rat aorta in order to more fully define the time course of ATP-evoked Ca(2+) signals. 20 microM ATP evoked a short-lasting Ca(2+) signal. However, medium stirring, high agonist concentrations, inhibition of ectonucleotidases and application of a poorly hydrolyzable agonist evoked long-lasting Ca(2+) signals (up to 20 min at 37 degrees C). These studies suggest that ATP is able to sustain a prolonged [Ca(2+)](i) increase, unless ectonucleotidase activity reduces the agonist concentration near the EC surface to subthreshold values, quickly cutting the Ca(2+) signal. Furthermore, the amplitude of the long-lasting phase of the Ca(2+) signal depended on the balance between agonist degradation by ectonucleotidases and agonist transport, by diffusion and convection, from bulk solution to the EC surface.     

The effect of losartan on global and focal cerebral perfusion and on renal function in hypertensives in mild early ischaemic stroke

BACKGROUND: Secondary prevention of stroke with antihypertensive drugs is now standard practice, but it is unclear how soon after a cerebrovascular event antihypertensive therapy should be initiated or re-started. Due to impaired cerebral autoregulation, changes in systemic blood pressure may be reflected in cerebral perfusion, especially in hypertensive patients immediately post-stroke. Conversely, early initiation in hospital may better assure continued long-term treatment. We have investigated the effect of the angiotensin II receptor antagonist (ARA) losartan on mean arterial blood pressure (MABP), global and focal cerebral blood flow (CBF), and glomerular filtration rate (GFR) in hypertensive patients 2-7 days after stroke. METHODS: Twenty-four patients without occlusive carotid disease but with MABP between 110 and 145 mmHg were studied within 2-7 days of ischaemic stroke/transient ischaemic attack (TIA). They were randomized to receive either placebo or losartan (25 or 50 mg daily). MABP and internal carotid artery (ICA) flow were measured at baseline, over the following 24 h and at 2 weeks. Brain hexamethylpropyleneamine oxime single photon emission computed tomography (HMPAO SPECT) was performed before dosing and at the estimated time of peak drug effect (6-8 h after the first dose). GFR was measured at baseline and at 2 weeks. RESULTS: The mean National Institutes of Health (NIH) score of randomized patients was 2.6; losartan was generally well tolerated and no patient suffered a deterioration in neurological function. A mean placebo-corrected intra-subject reduction in MABP of 9.5 mmHg was observed in treated patients from 1-12 h (P = 0.0001), with a maximal fall of 18.1 mmHg at 9 h post-dose (P = 0.002). No change occurred in ICA flow, or cortical or hemispheric CBF measured by HMPAO SPECT. No significant change in GFR was seen within or between groups. DISCUSSION: Losartan may be introduced within 2-7 days of mild stroke in hypertensive patients in whom significant carotid occlusive disease has been excluded without affecting global or regional CBF, or affecting GFR.     

Oral enzyme combination versus diclofenac in the treatment of osteoarthritis of the knee – a double-blind prospective randomized study

The aim of this study was to compare the efficacy and safety of an oral enzyme–rutosid combination (ERC) containing rutosid and the enzymes bromelain and trypsin, with that of diclofenac in patients with osteoarthritis (OA) of the knee. A total of 103 patients presenting with painful episodes of OA of the knee were treated for 6 weeks in two study centers in a randomized, double-blind, parallel group trial. Altogether, 52 patients were treated in the ERC group and 51 patients were treated in the diclofenac group. Primary efficacy criteria were Lequesnes Algofunctional Index (LFI) and a complaint index, including pain at rest, pain on motion and restricted function. The efficacy criteria were analyzed by applying the Wilcoxon–Mann–Whitney test that provides the Mann–Whitney estimator (MW) as a measure of relevance. Non-inferiority was considered to be proven if the lower bound of the 97.5% one-sided confidence interval (CI-LB) was higher than MW=0.36 (benchmark of not yet relevant inferiority). Both treatments resulted in clear improvements. Within the 6-week observation period, the mean value of the LFI decreased from 13.0 to 9.4 in the ERC group and from 12.5 to 9.4 in the diclofenac group. Non-inferiority of ERC was demonstrated by both primary criteria, LFI (MW=0.5305; CI-LB=0.4171) and complaint index (MW=0.5434; CI-LB=0.4296). Considerable improvements were also seen in secondary efficacy criteria, with a slight tendency towards superiority of ERC. The global judgment of efficacy by physician resulted in at least good ratings for 51.4% of the ERC patients, and for 37.2% of the diclofenac patients. In the majority of patients tolerability was judged in both drug groups as very good or good. The current study indicates that ERC can be considered as an effective and safe alternative to NSAIDs such as diclofenac in the treatment of painful episodes of OA of the knee. Placebo-controlled studies are now needed to confirm these results.Abbreviations ERC Enzyme–rutosid combination - LFI Lequesnes Algofunctional Index Dr. Mehnaz Rashid was the Clinical Trials monitor on behalf of Pacific Pharmaceuticals (Lahore, Pakistan) and Dr. W. Schiess played the same role on behalf of Mucos Pharma (Germany)     

Effects of oat beta-glucan on innate immunity and infection after exercise stress

PURPOSE: To test the effects of oat beta-glucan (ObetaG) on respiratory infection, macrophage antiviral resistance, and NK cytotoxicity. METHODS: Mice were randomly assigned to one of four groups: Ex-H2O, Ex-ObetaG, Con-H2O, or Con-ObetaG. ObetaG was fed in the drinking water for 10 d before intranasal inoculation of HSV-1 or sacrifice. Exercise consisted of treadmill running to volitional fatigue (approximately 140 min) for three consecutive days. Fifteen minutes after the last bout of exercise or rest, mice (N = 24) were intranasally inoculated with a standardized dose of HSV-1. Mice were monitored twice daily for morbidity and mortality. Additional mice were sacrificed after exercise, peritoneal macrophages were obtained via i.p. lavage and assayed for antiviral resistance to HSV-1 (N = 18), and spleens were harvested and assayed for NK cell cytotoxicity (N = 12). RESULTS: Exercise stress was associated with a 28% increase in morbidity (P = 0.036) and 18% increase in mortality (P = 0.15). Ingestion of ObetaG before infection prevented this increase in morbidity (P = 0.048) and mortality (P = 0.05). Exercise stress was associated with a decrease in macrophage antiviral resistance (P = 0.007), which was blocked by ingestion of ObetaG (P < 0.001). There were no effects of exercise or ObetaG on NK cytotoxicity. CONCLUSION: These data suggest that daily ingestion of ObetaG may offset the increased risk of URTI associated with exercise stress, which may be mediated, at least in part, by an increase in macrophage antiviral resistance.     

Mid-term to long-term followup of two-stage reimplantation for infected total knee arthroplasty

Between January 1989 and December 1994, 94 patients (96 knees) had a two-stage reimplantation for treatment of an infected total knee arthroplasty. All patients were treated with an interval antibiotic-loaded static cement spacer and had antibiotic-loaded bone cement for prosthesis fixation at the time of reimplantation. The purpose of this study was to assess the long-term risk of reinfection and the mechanical durability of these reimplantation arthroplasties. Patients were followed up for a median of 7.2 years (range, 2.5-13.2 years). At final followup, 15 knees (16%) had required reoperation. Nine knees (9%) had component removal for reinfection and six knees (6%) were revised for aseptic loosening. The median time to reoperation for reinfection was 1 year (range, 0.1-9.8 years). The risk of recurrent infection was not correlated with the type of organism, patient demographics, or method of prosthesis fixation at reimplantation. The survivorship free of implant removal for any reason was 90% (confidence intervals, 83.9-96.4%) at 5 years and 77.3% (confidence intervals, 65.5-89.6%) at 10 years. The survivorship free of implant removal for reinfection was 93.5% (confidence intervals, 88.5-98.7%) at 5 years and 85% (confidence intervals, 73.8-96.3%) at 10 years. Survival free of revision for mechanical failure (aseptic loosening or radiographic loosening) was 96.2% (confidence intervals, 92-100%) at 5 years and 91% (confidence intervals, 80.8-98.3%) at 10 years. These results suggest that the high likelihood of early success after two-stage reimplantation of an infected TKA is well maintained throughout long-term followup, with a modest rate of late recurrent infection or mechanical implant failure.     

Cytokine induction by the P. aeruginosa quorum sensing system during thermal injury

INTRODUCTION: Pseudomonas aeruginosa causes serious infections in severely burned patients due to its ability to produce numerous virulence factors. The production of most of these factors is controlled by the cell-to-cell communication system called quorum sensing (QS). We have recently shown that several proinflammatory and hematopoietic cytokines are produced during infection of the burn wound with P. aeruginosa strain PAO1. Most of these cytokines were not produced during either thermal injury or P. aeruginosa infection alone. MATERIALS AND METHODS AND RESULTS: In this study, we tried to determine if the QS systems play a role in the production of cytokines during P. aeruginosa infection of burn wounds. This was accomplished using the murine model of thermal injury, the P. aeruginosa strain PAO1 and its QS defective mutant (PAO-JP2), and the Multi-probe RNase protection assay. The mRNA for TNF-alpha, IL-6, TGF-beta, and G-CSF was detected within the skin of PAO1 infected/thermally injured mice. In contrast, the expression of these cytokines was not detected in PAO-JP2 infected/thermally injured mice. In comparison with the parent strain, PAO-JP2 was not defective either in its growth or in its spread within the thermally injured skin. A complementation experiment, using a plasmid that carries the intact QS gene, was conducted to confirm these results. In the presence of the complementing plasmid, PAO-JP2 produced the mRNA for the above cytokines. CONCLUSIONS: These results suggest that: 1) the QS system is involved in the induction of cytokine expression during P. aeruginosa infection of burn wounds; and 2) this effect may be caused by either a component of the QS system or a QS-controlled virulence factor.