Monitoring rheumatoid arthritis synovitis with 99mTc-anti-CD3.

The aim of this study was to investigate the feasibility of using a monoclonal antibody (OKT3) labelled with technetium-99m (99mTc) to monitor disease activity in patients with rheumatoid arthritis. We evaluated 38 patients who were diagnosed with rheumatoid arthritis and classified as Classes II and III after functional assessment (according to the revised criteria specified by the American College of Rheumatology). Two sets of planar anterior images of the patients' wrists, metacarpophalangeal and interphalangeal joints, elbows, shoulders and knees joints were obtained 1 h and 3 h after the injection of 99mTc-OKT3. The scintigraphic findings showed significant correlation (p<0.05) between the radiopharmaceutical accumulation of 99mTc-OKT3 and swollen joints, tender joints and the visual analogue scale. They were able to differentiate patients in remission from patients with active synovitis, according to DAS 28. In contrast, there was no correlation between the radiopharmaceutical accumulation and the patients' age, gender, duration of disease or erythrocyte sedimentation rate. A relatively high disease activity score of 28 joints (4.08+/-1.74) was found in the majority of patients. In conclusion, 99mTc-OKT3 scintigraphy is a reliable and objective method for detecting synovial activity, and can be used to observe disease prognosis.

Use of 99mTc-mononuclear leukocyte scintigraphy in nosocomial fever.

PURPOSE: To determine the overall diagnostic accuracy of mononuclear leukocyte- 99mTc scintigraphy in the routine detection of infectious lesions and fever of unknown origin (FUO) in inpatients. MATERIAL AND METHODS: The use of mononuclear leukocyte 99mTc scintigraphy is presented in 87 patients who fulfilled the Durack and Street diagnostic criteria of nosocomial FUO; 66 patients were suspected of having infectious lesions (myocarditis, endocarditis, infected catheters, diabetic foot, and osteomyelitis) and 21 patients presented with unknown causes of FUO. Scans were carried out 1, 3, and 24 h after injection of labeled leukocytes. RESULTS: In three cases (3/27) where scintigraphs were negative, biopsies were positive. There were two (2/87) false-positive scintigrams. We found a 95.8% sensitivity and 92.3% specificity. PPV was 93.8%, PPN 94.7%, and accuracy 94.2%. CONCLUSION: Mononuclear leukocyte 99mTc scintigraphy showed high sensitivity, specificity, positive and negative predictive values in patients with nosocomial FUO. These results suggest an important role for nuclear medicine in the management of patients with infection/inflammation.

Fructose-1,6 diphosphate as a protective agent for experimental ischemic acute renal failure.

Cold ischemia time is a risk factor for the development of acute renal failure in the immediate post-transplant period. In this study, we aimed to determine if intravenous fructose-1,6-diphosphate (FDP), given before nephrectomy, attenuates renal cell injury in a cold ischemia model. Male adult Wistar rats were subjected to infusion of either FDP 350 mg/kg (group F, n=6), an equal volume of 0.9% NaCl (group S, n=6), an equal volume/osmolality of mannitol (group M, n=6) or no infusion (group C, n=7). Kidneys were then perfused in situ with Collins solution and nephrectomy was performed. Other kidney slices were stored in Collins solution at 4 degrees C. Adenosine triphosphate (ATP) levels and lactate dehydrogenase (LDH) release were examined at 0, 24, 48 and 72 h. Other slices, obtained after 50 min immersion in Collins solution at 37 degrees C, were frozen for characterization of cytoskeletal preservation using phalloidin-FITC staining. Apical fluorescence intensity of proximal tubule cells, indicative of the F-actin concentration, was measured in a fluorescence microscope interfaced with computer image analysis system. Adenosine triphosphate levels, after up to 72 h of tissue incubation, were higher (P<0.05) in the FDP group when compared to other groups. In addition, LDH release was smaller (P<0.0001) in the FDP group. The F-actin concentration of proximal tubule cells cells was greater in the FDP group (P<0.0001). Results indicate that FDP is a useful tool to increase tissue viability in a rat kidney subjected to cold ischemia, by maintaining ATP cell content, decreasing LDH release and preventing microfilament disruption of proximal tubule cells.

Regulation of the renal Na-HCO(3) cotransporter X. Role of nitric oxide and intracellular calcium.

Cholinergic agents increase the activity of the renal Na-HCO(3) cotransporter and have been shown to stimulate the production of nitric oxide (NO) in other cells. To study the role of NO in mediating the effect of carbachol on Na-HCO(3) cotransporter, we measured the activity of the cotransporter in rabbit proximal tubule cells treated with carbachol (10(-4 )M) or the NO inhibitor, L-NAME (10(-3) M), or carbachol+L-NAME. The activity of NaHCO(3) cotransporter was measured by recovery of intracellular pH (pH(i)) in cells loaded with pH-sensitive dye, BCECF. In control cells, carbachol significantly increased Na-HCO(3) cotransporter activity while L-NAME did not affect the activity of the cotransporter but completely blocked the enhancement induced by carbachol. Carbachol increased NO production by proximal tubule cells. We also studied the effect of the NO donor, SNAP (10(-3) M), on the cotransporter incubated for 1 h in cultured proximal tubule cells. SNAP caused a similar enhancement in the activity of the cotransporter suggesting that a different NO donor is capable of enhancing the activity of the cotransporter to the same extent as that observed with carbachol. Because the effect of NO is thought to involve cGMP, we examined the effect of 8-Br-cGMP (10(-3 )M) on the cotransporter. 8-Br-cGMP caused stimulation of the Na-HCO(3) cotransporter activity although to a lesser degree than carbachol. We have previously shown that carbachol increases cytosolic calcium but the role of intracellular calcium (Ca(i)) per se on the cotransporter has not been studied. We therefore studied the role of Ca(i) on the activity of Na-HCO(3) cotransporter in rabbit proximal tubule cells by utilizing the calcium ionophore, ionomycin, the microsomal Ca-ATPase inhibitor, thapsigargin, and the calcium chelator, BAPTA. Ionomycin, 5 microM, caused a significant stimulation of Na-HCO(3) cotransporter which was prevented by BAPTA. The microsomal Ca-ATPase inhibitor, thapsigargin, also increased the cotransporter activity. As expected both ionomycin and thapsigargin caused a significant increase in Ca(i). Calyculin A, an inhibitor of protein phosphatase 2A prevented the stimulation of the cotransporter by calcium (in pH units/min: control 1.8+/-0.13; Ca 2.22+/-0.07; p<0.05; Ca+calyculin A 1.9+/-0.09, p<0.025) suggesting that calcium acting through kinases/phosphatases, plays a role in the phosphorylation of the cotransporter. These results demonstrate that NO and Ca(i) modulate the activity of the cotransporter.

Regulation of the renal Na-HCO3 cotransporter: IX. Modulation by insulin, epidermal growth factor and carbachol.

To examine the role of tyrosine kinase (TK) on basolateral membrane (BLM) transport, we looked for the presence of TK activity in these membranes and showed that the synthetic substrate for TK, poly [Glu80 Na, Tyr20] caused a three-fold increase in tyrosine phosphorylation. This effect was completely blocked by the TK inhibitors, 2-hydroxy-5(2,5-dihydroxybenzyl) aminobenzoic acid (HAC), 1 microM, and methyl 2,5-dihydroxycinnamate (DHC), 5 microM. We then examined the effect of agents that cause TK stimulation on tyrosine kinase immunocontent and on the Na-HCO3 cotransporter activity in BLM and in primary cultures of the proximal tubule. We utilized the cholinergic agent, carbachol (10(-4) M), epidermal growth factor (EGF 10(-8) M), and insulin (10(-8) M), well known activators of TK. Carbachol, insulin, and EGF caused a significant increase in TK immunoreactive protein content which was blocked by HAC and DHC. In BLM, carbachol significantly stimulated HCO3-dependent 22Na uptake and this effect was totally prevented by the monoclonal antibody against TK. In cultured proximal tubule cells, carbachol, EGF and insulin at physiologic concentration caused a significant stimulation of the cotransporter activity and this effect was completely blocked by the TK inhibitor, HAC. Increasing the dose of insulin 100-fold did not cause further stimulation of the cotransporter indicating that insulin plays a permissive role on the cotransporter. These results demonstrate the presence of TK in renal proximal tubule cells and show that activation of this kinase by dissimilar agents enhance the activity of the Na-HCO3 cotransporter.

Regulation of renal Na-HCO3 cotransporter: VIII. Mechanism Of stimulatory effect of respiratory acidosis.

We examined the effect of respiratory acidosis on the Na-HCO3 cotransporter activity in primary cultures of the proximal tubule of the rabbit exposed to 10% CO2 for 5 min, 2, 4, 24 and 48 hr. Cells exposed to 10% CO2 showed a significant increase in Na-HCO3 cotransporter activity (expressed as % of control levels, 5 min: 142 +/- 6, 2 hr: 144 +/- 13, 4 hr: 145 +/- 11, 24 hr: 150 +/- 15, 48 hr: 162 +/- 24). The increase in activity was reversible after 48 hr. The role of protein kinase C (PKC) on the stimulatory effect of respiratory acidosis on the cotransporter was examined in presence of PKC inhibitor calphostin C or in presence of PKC depletion. Both calphostin C and PKC depletion prevented the effect of 10% CO2 for 5 min or 4 hr to increase the activity of the cotransporter. 10% CO2 for 5 min or 4 hr increased total and particulate fraction PKC activity. To examine the role of phosphotyrosine kinase (PTK) on the increase in cotransporter activity we studied the effect of two different inhibitors, 2-hydroxy-5-(2,5-dihydroxylbenzyl) aminobenzoic acid (HAC) and methyl 2,5-dihydroxycinnamate (DHC) which inhibit phosphotyrosine kinase in basolateral membranes. Cells were pretreated either with vehicle or HAC or DHC and then exposed to 10% CO2 for 5 min or 4 hr. In cells treated with vehicle, 10% CO2 significantly increased cotransporter activity as compared to control cells exposed to 5% CO2. This stimulation by 10% CO2 was completely prevented by HAC or DHC at 5 min (5% CO2: 1.8 +/- 0.2, 10% CO2: 2.6 +/- 0.2, 10% CO2 + HAC: 1.6 +/- 0.2, 10% CO2: +DHC: 2.0 +/- 0.3 pH unit/min) and also at 4 hr. The protein synthesis inhibitors actinomycin D and cycloheximide appear to prevent the effect of 10% CO2 for 4 hr on the cotransporter. Our results show that early respiratory acidosis stimulates the Na-HCO3 cotransporter through PKC and PTK-dependent mechanisms and the late effect appears to be mediated through protein synthesis.

Effect of the antiglucocorticoid RU-486 on glomerular hemodynamics in remnant nephrons.

Endogenous glucocorticoid (GC) has been proposed to play a role in the adaptive functions of remnant nephron and participates in the progression of renal disease. The effect of GC blockade by RU-486 (20 mg/kg), an anti-GC agent, on the progression of chronic renal failure (CRF) was evaluated in Munich-Wistar rats. CRF was induced by 5/6 nephrectomy. Global renal function, glomerular hemodynamics, proteinuria and renal histopathology studies were performed after 60 days of CRF induction. RU administration in control or CRF groups did not induce significant changes in total renal function, mean arterial or intraglomerular hydraulic pressures, 24-hour proteinuria or sclerosis index. However, RU induced a significant reduction in single-nephron glomerular filtration rate in the superficial nephrons in both groups' control (decreases 20%) and CRF (decreases 57%), without changing total glomerular filtration rate, when compared with vehicle administration. These reductions were due to a decline in glomerular plasma flow rate (QA) and in glomerular ultrafiltration coefficient (Kf). These data suggest that GC played a role in the adaptive hyperfiltration associated with the compensatory mechanism but did not participate in the genesis of proteinuria or glomerulosclerosis in this experimental model.

Regulation of the renal Na-HCO3 cotransporter: VII. Mechanism of the cholinergic stimulation.

Cholinergic agents regulate proximal tubule acidification but the mechanism responsible for this effect is unclear. We examined the effect of the cholinergic agent carbachol on the activity of the Na-HCO3 cotransporter in primary cultures of the proximal tubule of the rabbit. The activity of the cotransporter was assayed either as HCO3-dependent 22Na uptake or as the recovery of intracellular pH in cells perfused continuously with Cl-free physiologic solution containing amiloride to block the Na-H antiporter. Carbachol caused a dose-dependent stimulation of the cotransporter activity with a maximum increase of 90% above control values at 10(-5) M and half maximal stimulation at 10(-7) M. The stimulation was blocked by atropine and pirenzepine indicating an effect through the M1 muscarinic receptor. Carbachol increased intracellular calcium fourfold and the rise in cytosolic calcium was prevented by the intracellular calcium chelator, BAPTA. BAPTA also blocked the effect of carbachol on the cotransporter. Because carbachol activates phospholipase C and protein kinase C, we examined the effect of carbachol in the presence of the phospholipase C inhibitor, U73122, or the PKC inhibitor, calphostin C, or PKC depletion. The phospholipase C inhibitor prevented both the effect of carbachol on the cotransporter and on the intracellular Ca. Calphostin C and PKC depletion also prevented the stimulation of the cotransporter. Carbachol increased PKC activity and caused translocation of the PKC to the particulate fraction. We also examined the effect of the phosphatase inhibitor, calyculin A or the calmodulin kinase inhibitor, W-13 on carbachol stimulation. Calyculin A and W13 likewise prevented the carbachol-induced stimulation of the cotransporter. These results demonstrate that cholinergic stimulation modulated the activity of the cotransporter through multiple pathways including phospholipase C/PKC and phosphatase systems.

Fructose-1,6-diphosphate: potential protection in cyclosporine-induced renal impairment.

There is evidence that fructose-1,6-diphosphate (FDP) provides protection from hepatic and cardiac toxic-induced damage and ischemic renal insult. To determine if FDP also protects against cyclosporine (CsA)-induced nephrotoxicity, two groups of adult male Wistar rats were studied for whole kidney clearance rates. After two initial control periods, group 1 received only CsA (CsA, n = 8). Group 2 received FDP 350 mg/kg, followed by CsA 50 mg/kg (FDP-CsA, n = 6). In both groups, after a 30-min equilibration period, two additional clearance rates were measured (Post 1 and Post 2). A significant reduction in clearance rates was observed after drug infusion in both groups (approximately 58 and 64% in CsA and FDP-CsA groups, respectively, p < 0.05) with a recovery to control values in the Post 2 period in the FDP-CsA group. These data suggest a protective effect of FDP on CsA-induced renal impairment.

Aneurisma da arteria esplenica. / Aneurysm of splenic artery

Apresentam os autores a experiencia de dois casos de aneurismas de arteria esplenica agudos no servico de cirurgia do HECC. Fazem revisao da literatura enfatizando o exame fisico e radiologico simples do abdomen dados fundamentais para o diagnostico em que o sinal do "anel de sinete" devera ser sempre pesquisado. Referem ainda os magnificos resultados obtidos com a aneurismectomia e esplenectomia