Distribution of donor-specific antibodies in the cortex and the medulla of renal transplants with chronic allograft nephropathy

BACKGROUND: Emerging data suggest that donor-specific HLA antibodies should be more frequently found onto the transplant itself than in the bloodstream. It is now possible to detect such antibodies in kidney transplant needle biopsy samples by flow cytometry. In order to know if the detection of antibodies into such blind biopsy samples depends of the site of the biopsy, we have studied the distribution of antibodies in both the cortex and medulla of 12 transplants removed after graft loss due to chronic allograft nephropathy, and in 10 controls. METHODS: Donor-specific HLA antibodies were extracted from the cortex and the medulla of each removed transplant by an acid elution and characterized by Luminex assays. RESULTS: They were found in 58.3% of transplants with chronic allograft nephropathy and never in other kidney samples. The same antibodies were found in the bloodstream at the time of transplantectomy in only 16.6% of the recipients. The distribution between the cortex and medulla was concordant in 75% of cases. However, we observed 2 discrepancies: one in favor of the cortex and one in favor of the medulla. A majority (5/7) transplants with CAN and intra-graft donor-specific antibodies had also C4d deposits along peritubular capillaries. CONCLUSION: Testing for donor-specific HLA antibodies in kidney transplant needle biopsies can be of value provided the biopsy includes both the cortex and the medulla.     

Small Is Beautiful: Why Profundaplasty Should Not Be Forgotten

Background

Surgical profundaplasty (SP)is used mainly as an adjunct to endovascular management of peripheral vascular disease (PAD) today. Results from earlier series of profundaplasty alone have been controversial, especially regarding its hemodynamic effect. The question is: Can profundaplasty alone still be useful? Our aim was to evaluate its role in the modern management of vascular patients.

Methods

This was a retrospective outcome study. A consecutive series of 97 patients (106 legs) from January 2000 through December 2003 were included. In 55 (52%) legs, the superficial femoral artery was occluded. These patients were included in the current analysis. Of these patients 14 (25%) were female. Mean age was 71 ((11) years. Nineteen (35%) were diabetic. The indication for operation was claudication in 29 (53%), critical leg ischemia (CLI) in 26 (47%), either with rest pain in 17 (31%), or ulcer/gangrene in 9 (16%). Endarterectomy with patch angioplasty with bovine pericardium was performed in all cases. Mean follow-up was 33 ( 14 months. Mean preoperative ankle brachial index (ABI) was 0.6. Sustained clinical efficacy was defined as upward shift of 1 or greater on the Rutherford scale without repeat target limb revascularization (TLR) or amputation. Mortality, morbidity, need for TLR, or amputation were separate endpoints.

Results

Postoperatively, ABI was significantly improved (mean = 0.7), in 24 (44%) by more than 0.15. At three years, cumulative clinical success rate was 80%. Overall, patients with claudication had a better outcome than those with CLI (p = 0.04). Two (4%) major amputations and 2 (4%) minor ones were performed, all in patients with CLI. None of the 9 (16%) ulcers healed.

Conclusion

Profundaplasty is still a valuable option for patients with femoral PAD and claudication without tissue loss. It is a straightforward procedure that combines good efficacy with low complication rates. Further endovascular treatment may be facilitated. It is not useful for patients with the combination of critical ischemia and tissue loss.

     

Revascularization for chronic critical lower limb ischemia in octogenarians is worthwhile

OBJECTIVE: Advanced age is considered a relative contraindication for surgical revascularization in patients with peripheral arterial occlusive disease. Our aim was to analyze the usefulness of endovascular and surgical revascularization in patients older than 80 years with chronic critical leg ischemia (CLI). Our hypothesis was that the clinical benefit of lower extremity revascularization is limited in octogenarians. METHODS: This was a prospective cohort study with a 1-year follow-up. Subjects included a consecutive series (January 1999 to June 2004) of patients presenting with CLI. Revascularization cohorts were either open surgical or endovascular with conservatively treated patients as a reference group. Prospective follow-up occurred after 30 days and 2, 6, and 12 months. The primary end point was sustained clinical success, defined as a categorical upward shift in clinical symptoms according to Rutherford, without major amputation and without the need for repeated target extremity revascularization (TER). Secondary clinical success was defined accordingly, including repeated TER. Mortality, major amputation, and TER were separately calculated end points. All results were stratified for age categories of nonoctogenarians (<80 years) and octogenarians (> or =80 years). Cumulative outcome was determined by the Kaplan-Meier method, and differences were assessed by log-rank tests. Multivariable analysis was performed by using Cox proportional regression. RESULTS: A total of 376 patients (158 women; mean age, 75.8 +/- 10.7 years) with 416 critically ischemic limbs were analyzed. Overall, 150 patients (39.9%) were older than 80 years, and 85 limbs were treated surgically (26 octogenarians; 30.6%), 207 limbs (96 octogenarians; 46.4%) were treated by endovascular means, and 124 limbs (45 octogenarians; 36.3%) were treated conservatively, including delayed revascularization procedures. Both sustained and secondary clinical success rates, as well as limb salvage rates, were higher in the revascularization cohorts as compared with conservatively treated patients, regardless of age category (P < .001, P < .001, and P = .006, respectively, by Cox proportional hazard model). Mortality was significantly higher in octogenarians (P = .006 by Cox proportional hazard model), particularly within 30 days after surgical revascularization (hazard ratio, 5.35; 95% confidence interval, 1.15-24.9). Patient age category did not affect the rate of major amputations or TER. CONCLUSIONS: Individually tailored revascularization improves the outcome of CLI in octogenarians as well as in nonoctogenarians; even so, endovascular revascularization should be preferred in octogenarians because of the higher mortality associated with surgery.     

Invalidisierende Kalziphylaxie (Calcific uraemic arteriolopathy)

We present the case of a 45-year-old man with diabetes mellitus type 1 and end-stage renal failure who was treated with haemodialysis for 2 years and received a renal transplant at the age of 35. Due to clinical progression with recurrent acral necrosis, the diagnosis of calciphylaxis was made. Over the course of time, many amputations on both hands and legs were necessary. The pathogenesis, clinical features, diagnosis, and treatment of calciphylaxis are discussed.     

General biochemical and immunological characterization of the venom from the scorpion Tityus trivittatus of Argentina

Tityus trivittatus is the Argentinean scorpion reported to cause the majority of human fatalities in the country, however no systematic studies have been conducted with the venom of this species. This communication describes a general biochemical and immunological characterization of the venom obtained from T. trivittatus scorpions collected in the city of Buenos Aires and various provinces of Argentina: Catamarca, Cordoba, Entre Rios, La Rioja, Santa Fe and Santiago del Estero. These are places where human accidents were reported to occur due to this scorpion. For comparative purposes two types of samples were assayed: whole soluble venom obtained by electrical stimulation and supernatant from homogenized venomous glands. Two strains of mice (NIH and CF-1) were used for LD₅₀ determinations by two distinct routes of administration (intravenously and intraperitoneally). Important variations were found that goes from 0.5 to 12 mg/kg mouse body weight. Samples of soluble venom were always more potent than Telson homogenates. More complex pattern was observed in homogenates compared to soluble venom, as expected. This was supported by gel electrophoretic analysis and high performance liquid chromatographic (HPLC) separations. Additionally, the HPLC profile was enriched in proteins resolved at similar elution times as other known toxins from scorpion venoms studied. Immune enzymatic assays were also conducted comparatively, using four different anti-venoms commercially available for treatment of scorpion stings (Argentinean antidote from INPB, two anti-venoms from Butantan Institute of Brazil and Alacramyn from the Mexican Bioclon Institute). Cross-reactivities were observed and are reported among the various venoms and anti-venoms used. Lung, heart, liver and pancreas pathological modifications were observed on tissues of intoxicated mice. It seems that there are important variations on the venom compositions of the various samples studied and reported here, depending on the geographical area where the scorpions were captured. The results reported here are important for the clinical outcome of human accidents.     

Genotypic profiles by AP-PCR of streptococcus mutans in caries-active and caries-free preschoolers

Streptococcus mutans, an acidogenic and aciduric microorganism that colonizes the oral cavity is recognized as the main causal agent of dental caries. Epidemiological studies have shown a strong correlation between the number of S. mutans in the oral cavity and prevalence and incidence of caries. At present, different genotypic and phenotypic methods are known to determine the profiles of settling and epidemiological distribution of S. mutans. The aim of this study was to investigate the profiles of S. mutans isolated from children with and without dental caries by using the AP-PCR (arbitrarily primed polymerase chain reaction) and api-Zym methods. In the AP-PCR method, random DNA segments of the target bacterium are amplified with single primers of arbitrary sequence. The api-Zym system (bioMirieux, Marcy-létoile, France) is a phenotypic micro-method that allows simultaneous detection of 19 enzymatic activities from bacterial inoculum. A transversal observational study was conducted, which finally included 1203- to 5-year-old children (75 with and 45 without dental caries), who attended a preschool institution in Bogota (Colombia). S. mutans was isolated from 15 of the 45 children without dental caries (33.3%) and from 31 of the 75 children with caries (41.33%). In the 46 children, 69 S. mutans isolates were identified: 24 isolates in the 15 children without dental caries and 45 isolates in 31 children with dental caries. With api-Zym system, 36 different phenotypes were detected: 22 in the caries group and 15 in the caries-free group. The phenotype XX was present in both groups. With the AP-PCR method, 27 different fingerprinting profiles were identified: 22 for the caries group and 9 of the healthy group; the two groups of patients shared four of these genomic profiles. In conclusion, the information shows a great diversity in S. mutans genotypes and phenotypes in the population studied.     

Anticariogenic activity of the active fraction from Isertia laevis against S. mutans and S. sobrinus: comparison of two extraction methods

Dental caries is considered a multi-factorial, infectious, chronic, localized, post-eruptive, transmissible disease that leads to the destruction of dental hard tissue. The recognition of Streptococcus mutans as the major bacterial species involved in dental caries has led to the implementation of prevention and control measures for eliminating or reducing it in oral cavity. The main goal of research on medicinal plants is the search for substances or compounds with antimicrobial activity. The aim of this study was to evaluate the antimicrobial activity of fractions obtained by two methods from Isertia laevis against S. mutans and S. sobrinus. The plant material was collected in Medina (Colombia), at an elevation of 550 meters above sea level. From the ethanol extract of leaves of I. laevis, fractions were obtained by two methods: extraction by column vacuum chromatography (CVC) and extraction by continuous liquid/liquid partitioning (CLLP). The evaluation of the antimicrobial activity of fractions against S. mutans and S. sobrinus was performed by well diffusion and bioautography assays. From the CVC technique, only the methanol and methanol-dichloromethane fractions showed activity against S. mutans and S. sobrinus, with a minimum inhibitory concentration of 2 mg/well. From the CLLP technique, only the dichloromethane fraction showed activity against both microorganisms, with a minimum inhibitory concentration of 1 mg/well. Compounds C1 and C2 were isolated from the three active fractions, and showed a minimum inhibitory concentration of 0.4 mg/well for S. mutans and S. sobrinus, with zones of inhibition measuring 6.5 and 6.2 mm, respectively. In conclusion: 1) the three active fractions of I. laevis showed activity against S. mutans and S. sobrinus, 2) compounds C1 and C2 were presen equally in the three active fractions showing activity against the two bacteria, 3) compounds C1 and C2 may be triterpenoid and/or steroidal saponin structures, and 4) the two extraction methods lead equally to obtaining the active fractions.