Portomesenteric vein gas: diagnostic and prognostic value

Portomesenteric pneumatosis has been traditionally associated with intestinal infarction and poor outcome; however, recent studies have questioned its clinical value. To assess its diagnostic and prognostic significance we have retrospectively evaluated 47 patients correlating the CT finding of portomesenteric vein gas with clinical data and outcome. Thirty-nine patients (83%) had surgical evidence of intestinal infarction, four had necrotic small bowel volvulus (8.5%), two had blunt trauma, one had necrotic gastric volvulus, and one a gastric mucosal lesion induced by a nasogastric tube. Fifteen patients survived (31.9%); only 8/39 patients with intestinal infarction survived. Portomesenteric pneumatosis is a reliable marker of intestinal infarction and poor outcome; however, in trauma patients this sign is associated with a better prognosis. Electronic Publication     

Serum glomerular permeability activity in patients with podocin mutations (NPHS2) and steroid-resistant nephrotic syndrome

A plasma factor displaying permeability activity in vitro and possibly determining proteinuria has been hypothesized in idiopathic focal segmental glomerulosclerosis (FSGS). In vitro permeability activity (P(alb)) was determined in sera of five patients with autosomal recessive steroid-resistant nephrotic syndrome (NPHS2), an inherited condition indistinguishable from idiopathic FSGS on clinical grounds, but in which proteinuria is determined by homozygous mutations of podocin, a key component of the glomerular podocyte. All patients had presented intractable proteinuria with nephrotic syndrome; four developed renal failure and received a renal allograft. For comparison, sera from 31 children with nephrotic syndrome were tested. Pretransplant P(alb) was high in all cases (mean 0.81 +/- 0.06), equivalent to levels observed in idiopathic FSGS. Overall, P(alb) did not correlate with proteinuria. The posttransplant outcome was complicated in two patients by recurrence of proteinuria after 10 and 300 d, respectively, that responded to plasmapheresis plus cyclophosphamide. P(alb) levels were high at the time of the recurrence episodes and steadily decreased after plasmapheresis, to reach normal levels in the absence of proteinuria after the seventh cycle. In an attempt to explain high P(alb) in these patients, putative inhibitors of the permeability activity were studied. Coincubation of serum with homologous nephrotic urine reduced P(alb) to 0, whereas normal urine did not determine any change, which suggests loss of inhibitory substances in nephrotic urine. The urinary levels of the serum P(alb) inhibitors apo J and apo E were negligible in all cases, thus suggesting that other urinary inhibitors were responsible for the neutralizing effect. These data indicate that P(alb) is high in NPHS2, probably resulting from loss of inhibitors in urine. Lack of correlation of P(alb) with proteinuria suggests a selective loss of inhibitors. As in idiopathic FSGS, proteinuria may also recur after renal transplantation in NPHS2 patients, and post-transplant proteinuria is associated with high P(alb). The relationship between elevated P(alb) and proteinuria in NPHS2 remains to be determined.     

Nocturnal hypoxemia predicts incident cardiovascular complications in dialysis patients

Nocturnal hypoxemia secondary to sleep apnea has long been implicated as a cardiovascular risk factor in renal failure, but to date there is no study that links nocturnal hypoxemia to cardiovascular outcomes in end-stage renal disease. Fifty uremic patients on regular dialysis treatment without primary sleep apnea, pulmonary diseases, or other illnesses that may cause sleep apnea underwent pulse oximetry studies during night and were followed up for 32 mo. Average nocturnal SaO(2), minimal SaO(2), and the number of episodes of hypoxemia were similar in patients who died during the follow-up and in patients who survived, and none of these parameters predicted all-cause mortality. Average nocturnal SaO(2) was significantly lower (P = 0.006) in patients who had cardiovascular events during the follow-up (94.7 +/- 2.9%) than in event-free patients (97.1 +/- 1.3%). In a Cox model, average nocturnal SaO(2) was the second factor in rank explaining these outcomes. In this model a 1% decrease in average nocturnal SaO(2) was associated with a 33% increase in the incident risk of fatal and nonfatal cardiovascular events. Furthermore the risk of cardiovascular events was 5.05 times higher in patients with average nocturnal SaO(2) <95% (95% CI 1.61 to 15.86) than in those above this threshold (P = 0.005). This study adds weight to the hypothesis that nocturnal hypoxemia in dialysis patients represents an important cardiovascular risk factor.     

Lymphocyte costimulatory receptors in renal disease and transplantation

Cell-to-cell signal exchange during antigen presentation deeply influences the profile and extent of the immune response. Together with the TCR/MHC-mediated signal, accessory signals are provided to the T cell by the antigen-presenting cell (APC), through specific receptor-ligand interactions that represent indispensable costimulation for T-cell activation and survival. The main costimulatory pathways are the B7 family members and the CD40-CD154 receptor-ligand pair. B7-1 and B7-2 costimulate T-cells by binding to CD28. Their binding is prevented by the neoexpression of CTLA4, a CD28 homologue that can deliver a negative signal. Another CD28-like molecule, called ICOS (inducible costimulator), has been described and binds B7RP-1, a third member of the B7 family, but not B7-1 and B7-2. The CD40-CD154 interaction works as a two way costimulatory system by triggering activation signals to both T-cell and APCs. Its importance is highlighted by the discovery that mutations of the CD154 gene are responsible for a severe human immunodeficiency. Disruption of the natural costimulatory interaction was highly effective for prevention and treatment in several experimental models of autoimmune disease and transplant rejection. This review focuses on the most significant advances in understanding the physiopathological events involving costimulatory molecules, and their impact on renal diseases and transplantation.     

Cefdinir: A comparative study of anhydrous vs. monohydrate form. Microstructure and tabletting behaviour.

Anhydrous cefdinir (AC) vs. monohydrated cefdinir (MHC) was compared in order to be used as antimicrobial in therapeutics. Different techniques have been used to characterize physically AC and MHC, and also a complete microstructural analysis of raw materials was carried out. Cefdinir and Maltodextrin QDM 500 (3:2) formulations were compressed in order to obtain tablets with typical dose of Cefdinir, i.e. 300 mg. Dissolution profiles were obtained for both AC and MHC tablets. Finally tablet X-ray diffraction was performed to ensure the stability of the monohydrated form after tabletting being clearly different in both AC and MHC crystals. AC crystal structure was agreed with the known pattern of anhydrous Cefdinir described in the literature. Microstructural analysis showed large differences in specific surface area (SSA), confirmed by mercury intrusion. Crystal structures of both AC and MHC were stable under mixing, compression and storing processes. Dissolution profiles were faster for hydrate form, probably related to microstructural properties of the crystal which remained after tabletting. In conclusion, it is possible to isolate Cefdinir in two forms anhydrous and monohydrate, well characterized and differentiated. The use of this later improves dissolution of tablet dosage form due to the lack of interconversion during tablet manufacture.     

Failing Hemodialysis Arteriovenous Fistula and Percutaneous Treatment: Imaging with CT, MRI and Digital Subtraction Angiography

Purpose: To evaluate failing hemodialysis arteriovenous fistulas with helical CT angiography (CTA), MR angiography (MRA), and digital subtraction angiography (DSA), and to compare the efficacy of the three techniques in detecting the number, location, grade, and extent of stenoses and in assessing the technical results of percutaneous transluminal angioplasty (PTA) and stenting. Methods: Thirteen patients with Brescia-Cimino arteriovenous fistula malfunction underwent MRA and CTA of the fistula and, within 1 week, DSA. A total of 11 PTAs were performed; in three cases an MR-compatible stent was placed. DSA served as the gold standard for comparison in all patients. The presence, site, and number of stenoses or occlusions and the technical results of percutaneous procedures were assessed with DSA, CTA, and MRA. Results: MRA underestimated a single stenosis in one patient; CTA and MRA did not overestimate any stenosis. Significant artifacts related to stent geometry and/or underlying metal were seen in MRA sequences in two cases. Conclusions: CT and MRI can provide information regarding the degree of vascular impairment, helping to stratify patients into those who can have PTA (single or multiple stenoses) versus those who require an operative procedure (occlusion). Conventional angiography can be reserved for candidates for percutaneous intervention.     

Percutaneous implantation of a catheter with subcutaneous reservoir for intraarterial regional chemotherapy: Technique and preliminary results

Purpose: We present the technique and the preliminary results of percutaneous implantation of intraarterial catheters connected to a subcutaneous infusion reservoir for prolonged regional chemotherapy of hepatic and extrahepatic tumors. Methods: Two hundred patients with primary or secondary hepatic neoplasms, pelvic, pancreatic, renal, lingual, and breast cancer underwent the procedure. The access was the left axillary artery (188 patients) and the femoral artery (12 patients). The catheter tip was placed in the hepatic (170 patients), hypogastric (18), splenic (4), internal thoracic (2), gastroduodenal (3), renal (2) or the external carotid artery (1). The catheter was connected to a subcutaneous reservoir and filled with heparin; chemotherapeutic infusion was subsequently started. Results: One hundred percent immediate technical success was obtained. Forty-three of 200 (21.5%) patients had a complication: 29 patients had a catheter dislodgment, nine had arterial thrombosis, three had a pseudoaneurysm of the left axillary artery and two had a port pocket hematoma. Most complications (37/43, 86%) were treated percutaneously without interruption of chemotherapy. In only six cases (3% of the total population) was chemotherapy discontinued due to the complication itself. The mean duration of catheter patency was 7.2 months. Conclusion: Percutaneous placement of an intraarterial catheter is feasible and causes less discomfort to the patient than the surgical approach. The technique has an acceptable complication rate (21.5%), similar to that for surgical implantation (17.8%), with the advantage that in most cases the complications can be resolved percutaneously. This technique represents an alternative to surgical implantation in the treatment of liver metastases from colorectal cancer and opens new therapeutic possibilities for the local prolonged treatment of other kinds of tumor, though its clinical efficacy must be assessed in selected trials.     

Visual outcome and success of amblyopia treatment in unilateral small posterior lens opacities and lenticonus initially treated nonsurgically.

PURPOSE: We sought to assess the success of amblyopia treatment in patients with small posterior lens opacities as well as the factors associated with a good visual outcome. METHODS: This was a retrospective study of patients with posterior lens opacities that initially were thought to be too small in size to warrant cataract surgery. The following variables were examined: cataract type, location, diameter, persistent hyaloid vessel, anisometropia, strabismus, and age of detection. Success of treatment of amblyopia was defined as improvement by at least 0.3 logMAR units. Good visual outcome was defined as 20/40 or better. Amblyopia was treated by glasses, patching, and/or atropine. Patients who failed with conservative treatment or had an increase in cataract size underwent surgery. RESULTS: Forty-eight (91%) of 53 eyes were amblyopic. Thirty amblyopic eyes had pre- and post-treatment Snellen acuities. Twenty (67%) had their visual acuity (VA) improved by 0.3 logMAR units or greater. None of the measured variables were associated with successful amblyopia treatment. Twenty-five (49%) of 51 patients had a final VA of 20/40 or better. The only variable associated with good visual outcome was cataract type: 18 of 25 (72%) posterior subcapsular cataract and 6 of 23 (32%) posterior lenticonus eyes achieved VA of 20/40 or better (P = 0.008). Six patients who went on to have cataract surgery experienced a larger improvement in BCVA (4.50 logMar units +/- 2.52 lines) compared with patients treated without cataract surgery (2.36 logMar units +/- 3.11 lines). DISCUSSION: Amblyopia treatment was successful in most cases. A small group of patients who underwent cataract surgery experienced a greater VA improvement; however, it was not statistically significant. Further studies are needed to determine which patients would benefit from cataract surgery.