Fibrin generated in the synovial fluid activates intimal cells from their apical surface: a sequential morphological study in antigen-induced arthritis

OBJECTIVE: Fibrin deposits adhered to the synovial surface are typical of rheumatoid joints. Since fibrin appears to have a role in arthritis perpetuation our aim was to investigate how these deposits are formed and the consequences of their adhesion to the tissue. METHODS: The appearance of fibrin aggregates either free in the synovial fluid or attached to the membrane was studied in rabbits with antigen-induced arthritis by histological techniques at different time points from challenge. In the fixed synovial membranes areas of fibrin-bound synovium were evaluated by qualitative variables to obtain a sequential profile of morphological changes. RESULTS: Fibrin aggregates appeared from the initial stages of the disease in the synovial effusion. Later on, they were localized on the synovial surface and progressive changes were noted at the fibrin-tissue interface, ending with the invasion of the aggregates by synovial cells and their incorporation into the tissue. CONCLUSION: Fibrin aggregates generated inside the joint cavity may constitute a source of activation and acquisition of invasiveness of the synovial fibroblasts, a process to explore within the perpetuating mechanisms of rheumatoid arthritis.     

Acute myocardial infarction after blunt chest trauma in young people: Need for prompt intervention

We describe four cases of acute myocardial infarction in young patients, secondary to blunt chest trauma. One case was treated with intracoronary thrombolysls and angioplasty, two cases received systemic thrombolysis, and the last one did not have any reperfusion therapy. The coronary angiograms of the left anterior descending artery showed thrombosis in two cases, coronary dissection in one case, and no morphological lesions in the other. We encourage the early performance of angiographic studies in these patients, adjusting the therapy to their pathophysiologic mechanism.     

Peripheral-type benzodiazepine receptors are highly concentrated in mitochondrial membranes of rat testicular interstitial cells

The binding of 3H-RO 5-4864 to the peripheral-type benzodiazepine receptors (PBZDR) in rat testicular interstitial cells (TIC) was characterized. The binding was saturable, reversible and showed a single high-affinity (Kd = 5.02 +/- 0.86 nM) class of binding sites. The maximal binding capacity (Bmax) in crude mitochondrial fractions (77.6 +/- 9.1 pmol/mg protein) represents the highest density of PBZDR in tissues thus far studied. In comparison with the crude mitochondrial fraction the subcellular fractionation of TIC revealed a 2-fold enrichment of 3H-RO 5-4864 binding sites to the purified mitochondria (Bmax = 140 +/- 23 pmol/mg protein). The ability of various drugs to displace 3H-RO 5-4864 from TIC binding sites was examined and the inhibition constants (Ki) for RO 5-4864, PK 11195, diazepam and flunitrazepam were 3.5, 4.4, 159, and 353 nM, respectively, whereas clonazepam and RO 15-1788 were inefficient in displacing 3H-RO 5-4864 (Ki greater than 10 microM). This pharmacological profile is characteristic of PBZDR described in other tissues. In conclusion, rat TIC possess a very high concentration of PBZDR primarily associated with mitochondrial membranes.     

Usefulness of the Biofeedback Diacontrol module in the automatic programming of plasmatic conductivity and ionic mass transfer

Programmed variable sodium in the dialysate can improve hypotension during hemodialysis but may also alter sodium balance and thus resulting in a increase of water intake and weight gain between dialysis sessions. The aim of this study was to evaluate the changes on plasma volume (PV), Ionic Mass Transfer (IMT) and plasma conductivity (PC) with two different hemodialysis techniques. We studied 10 patients during a four-period protocol (one week each: PF1-DC1-DC2PF2): 120 dialysis sessions. During periods PF1 and PF2, the dialysis procedure was as usual, with exponential decrease of dialysate conductivity (DC) profile (15.7 mS/cm at start, 14.4 mS/cm at middle and 13.8 mS/cm at the end of the session) and UF profile (1.7 1/h at start and 0.1 1/h at the end). During periods DC1 and DC2, DC was automatically determined by a biofeedback modulae (Diacontrol) in order to reach a plasma water conductivity fixed at 14 mS/cm. All hemodialysis parameters were the same for the four periods: duration, blood and dialysate flow rates, dialysis membrane. A lower reduction of PV was evident on PF1 and PF2 (104 +/- 3.26% and -4.36 +/- 2.7%) compared with DC 1 and DC2 (-6.53 +/- 3.31% and -6.67 +/- 3.12%) (p < 0.001). No significant differences were seen in systolic, mean and diastolic blood pressure pre-HD or post-HD, UF, and weight gain, between the four periods. Hypotensive episodes were seen in 33.3% of PF1, 20% of DC1, 23.3% of DC2 and 26.6% of PF2 sessions (NS). PF1 and PF2 periods resulted in a significantly higher 30', mid and post-dialysis PC as compared to DC1 and DC2 periods (p < 0.001). The mean difference between the actual value and the prescribed value of PC at the end of the session was -0.01 +/- 0.07 mS/cm (n: 60). There was a negative correlation between the mean DC during session and the PC at 30' of session. IMT was 420.73 +/- 126.9 mEq in PF1, 311.96 +/- 161.75 in DC1, 278.34 +/- 153.14 in DC2 and 417.66 +/- 152.17 in PF2 (p > 0.001 PF1 and PF2 vs. DC1 and DC2). Diacontrol determines automatically an individualized DC profile for each patient, and accurately reaches the prescribed PC target. By reaching both the dry weight and PC settings, the water and sodium pool is maintained lower in the hemodialysis session using a biofeedback module. Clinical tolerance was similar in the two different dialysis procedures.