Callose deposition: a multifaceted plant defense response

Callose deposition in Arabidopsis has emerged as a popular model system to quantify activity of plant immunity. However, there has been a noticeable rise in contradicting reports about the regulation of pathogen-induced callose. To address this controversy, we have examined the robustness of callose deposition under different growth conditions and in response to two different pathogen-associated molecular patterns, the flagellin epitope Flg22 and the polysaccharide chitosan. Based on a commonly used hydroponic culture system, we found that variations in growth conditions have a major impact on the plant's overall capacity to deposit callose. This environmental variability correlated with levels of hydrogen peroxide (H₂O₂) production. Depending on the growth conditions, pretreatment with abscissic acid stimulated or repressed callose deposition. Despite a similar effect of growth conditions on Flg22- and chitosan-induced callose, both responses showed differences in timing, tissue responsiveness, and colocalization with H₂O₂. Furthermore, mutant analysis revealed that Flg22- and chitosan-induced callose differ in the requirement for the NADPH oxidase RBOHD, the glucosinolate regulatory enzymes VTC1 and PEN2, and the callose synthase PMR4. Our study demonstrates that callose is a multifaceted defense response that is controlled by distinct signaling pathways, depending on the environmental conditions and the challenging pathogen-associated molecular pattern.

Linear increase of the modal gain in 1.3 µm InAs/GaAs quantum dot lasers containing up to seven-stacked QD layers

The authors have recently demonstrated the enhancement of the quantum dot laser modal gain, linearly scaling with the number of stacked QD layers. These results allowed the achievement of multi-quantum dot (MQD) lasers, the zero-dimensional counterpart of MQW lasers, with a modal gain as high as 42 cm(-1), in a seven-layer structure. A detailed investigation of the structural and optical properties was performed on laser structures with three, five and seven QD layers. Such an investigation clearly shows that the high uniformity of QD layer features is responsible for the linear increase of the modal gain and its high value.

[Autoimmune hepatitis with elevation of CA 19-9 and normalization with immunosuppressant [corrected]treatment: case report and review of the literature]

We describe the case of an 81 year old woman that presented with jaundice, bile duct dilation, hepatic liver tests abnormalities and elevated levels of CA-19-9 (741 UI). Intestinal and pancreatic neoplasia were ruled out. Hepatic biopsy revealed chronic inflammation, cirrhosis and findings consistent with autoimmune hepatitis. The patient was given a course of corticoids and the disease as well as levels of CA-19-9 returned to normal levels.

Treatment with encapsulated Hsp60 peptide (p277) prolongs skin graft survival in a murine model of minor antigen disparity

The increased expression of heat shock protein (Hsp)60 in different kinds of graft tissues has been associated with a proinflammatory role and rejection. However, there are very few reports in which treatment with Hsp60 delays skin allograft rejection. The aim of this work was to evaluate the capacity of encapsulated human Hsp60-derived peptide p277 to delay graft rejection in two murine models of skin transplantation with minor antigen disparities. Briefly, BALB/c mice and C57BL/6 were intranasally pre-treated with five doses of Hsp60 p277 peptide encapsulated in polylactide-co-glycolide acid microspheres (PLGM), and received skin grafts from DBA2 mice and 129/B6 (F1) mice respectively. The treatment with the peptide increased skin graft survival more than 20 days in both the mouse strains, mainly in C57BL/6 recipients (P < 0.05). Also, p277-treated BALB/c and C57BL/6 mice showed IL-10 and IFN-gamma production, induced by p277 peptide. For the first time, a mucosal schedule using the Hsp60 C-terminal peptide p277 encapsulated in PLGM showed some survival prolongation of skin grafts bearing minor antigen disparities. Our results suggest a potential role for Hsp60-based therapy and the mucosal route as a useful tool to control the inflammatory response to allografts.

Organ Donation in Latin America

Recently in Latin America, there has been a strong influence of the "Spanish model" of organ procurement. In 2001, The "Punta Cana Group" was created by Latin American transplantation coordinators with the objective of registering and improving the system of donation and procurement. In many countries there is no universal financial support from the government for medical treatment, including dialysis and transplantation. In other countries there is complete financial support for all of the population, including immunosuppressive drugs. Practically all countries have transplantation laws that follow ethical concepts, such as brain death diagnosis criteria, forms of consent, criteria of allocation, and inhibition of commerce. The rate of potential donors notified in countries that perform transplantations with deceased donors varied from 6 to 47 per million population yearly (pmp/y); The rate of effective donors varied from 1 to 20 pmp. In 2004, the mean rate of effective donors in Latin America was 5.4 pmp. The family refusal rate for the donation of organs varied from 28% in Uruguay to 70% in Peru. In some countries, such as Puerto Rico, Uruguay, and Cuba, it was more than 15 pmp, whereas in others countries deceased donors were practically not used. The number of patients on the waiting list for solid organ transplants in 12 Latin American countries is 55,000. Although the donation rate has increased by 100% during the last 10 years, it is lower than that in Europe (15 pmm/y) or the United States (20 pmp/y).

Cellular autoreactivity against heat shock protein 60 in renal transplant patients: peripheral and graft-infiltrating responses

Autoreactivity to heat shock protein 60 (Hsp60) has been implicated in the pathogenesis and regulation of chronic inflammation, especially in autoimmune diseases. In transplantation, there is a lack of information regarding the cytokine profile and specificity of cells that recognize self-Hsp60 as well as the kinetics of autoreactivity following transplantation. We studied the cellular reactivity of peripheral and graft-infiltrating lymphocytes against Hsp60 in renal transplant patients. Cytokine production induced by this protein in peripheral blood mononuclear cells indicated a predominance of interleukin (IL)-10 during the late post-transplantation period, mainly in response to intermediate and C-terminal peptides. Patients with chronic rejection presented reactivity to Hsp60 with a higher IL-10/interferon (IFN)-gamma ratio compared to long-term clinically stable patients. Graft-infiltrating T cell lines, cocultured with antigen-presenting cells, preferentially produced IL-10 after Hsp60 stimulation. These results suggest that, besides its proinflammatory activity, autoreactivity to Hsp60 in transplantation may also have a regulatory role.

Evolution of Suboptimal Renal Transplantations: Experience of a Single Spanish Center

The increase in patients on dialysis awaiting transplantation has led to the use of grafts from suboptimal donors. The aim of this study was to analyze the function of suboptimal grafts. The secondary objectives were to study vascular and urological complications, as well as delayed renal function and acute rejection episodes. The study included 135 transplantations performed over 4 years with 27% of grafts being from suboptimal donors. Early graft loss was 12%, of which 69% were due to vascular thrombosis. These thromboses were more frequent among grafts from suboptimal donors (30% vs 4%, P < .001). There were no significant differences between the groups in the incidence of acute rejection episodes (17% vs 13%) or delayed graft function (14% vs 13%). A greater incidence of urologic complications was observed among recipients of grafts from older donors. The 1-year creatinine clearance was significantly lower among recipients of grafts from older donors (73 +/- 19 vs 51 +/- 14 mL/min, P < .0001). Sequential immunosuppressive therapy resulted in a lack of significant differences in creatinine clearance at 6 months, 1 year, or 2 years after transplantation between suboptimal grafts with cold ischemia greater or less than 20 hours or in warm ischemia greater or less than 60 minutes. Logistic regression analysis showed that the best determinant of graft loss was donor age older than 60 years. Accordingly, grafts from suboptimal donors were more likely to be lost during the first month after transplantation, particularly because of thrombosis, which was not due to a higher degree of technical complexity of the transplant operation.

PTFE Mesh in Renal Allograft Compartment Syndrome

We report a case of anuria in a 42-year-old female kidney transplant patient that occurred secondary to extrinsic compression from a large kidney being placed extraperitoneally in a small iliac fossa. Prompt reexploration in the immediate postoperative period resulted in salvage of the graft with restoration of kidney function. The abdominal wall was reconstructed using prosthetic mesh, which decreased the compartment pressure within the iliac fossa sufficiently to allow the renal vein patency and the kidney perfusion. We think that this tension-free surgical technique should be applied in those cases in which the retroperitoneal space is less than the size of the kidney to avoid renal allograft compartment syndrome or incisional hernia.

Intraoperative Parathyroid Hormone Monitoring During Parathyroidectomy for Hyperparathyroidism in Waiting List and Kidney Transplant Patients

This report describes the use of the intraoperative parathyroid hormone (ioPTH) assay during parathyroidectomy in waiting list and transplanted patients. ioPTH levels were determined in 40 patients on the waiting list for kidney transplantation with secondary hyperparathyroidism who underwent subtotal parathyroidectomy and 9 transplanted patients with tertiary hyperparathyroidism who underwent removal of hyperplasic glands. Rapid PTH levels decreased significantly at each time period; the percentage decrease in rapid PTH levels was 61.3% among patients with IPT II and 70.2% in patients with IPT III at 10 minutes and 86.5% in patients with IPT II and 91% in patients with IPT III at 15 minutes after excision of hypersecreting parathyroid tissue. A decrease of 50% or more from baseline PTH levels at 10 minutes and/or a decrease of 85% or more at 15 minutes predicted successful removal of abnormal parathyroid glands. The application of this technique during subtotal parathyroidectomy has proved useful for correct excision of parathyroid glands among waiting list patients with IPT II, while in kidney transplant patients with IPT III it allowed removal of only the pathological glands with a limited surgical approach.

Comparison of serological tests for the detection of ovine and caprine antibody to Brucella melitensis

The indirect enzyme-linked immunosorbent assay (IELISA), the competitive enzyme-linked immunosorbent assay (CELISA) and the fluorescence polarisation assay (FPA) were evaluated with sera from sheep experimentally infected with Brucella melitensis and negative Canadian sheep. The sensitivity and specificity of the assays were as follows: IELISA: 91.7% and 97.6%, CELISA: 75.0% and 99.8% and FPA: 91.7% and 89.5%. Sera from the same experimental population were divided according to serological reaction in the rose bengal agglutination test (RBT) and the complement fixation test (CFT). Reactivity relative to the RBT positive and CFT positive sera were as follows: IELISA: 99.7%, CELISA: 93.2% and FPA: 99.1%. Since sera from goats with proven B. melitensis infection were not available, 699 sera from goats judged positive in the buffered antigen plate agglutination test (BPAT) and CFT and 982 BPAT/CFT negative Canadian goats were used. The sensitivity and specificity of the assays relative to the BPAT and CFT positive sera were: IELISA: 99.4% and 98.0%, CELISA: 95.4% and 97.1% and FPA: 92.7% and 99.8%.

Simultaneous imbibition–heat convection process in a non-Darcian porous medium

In the present work, the nonisothermal imbibition process in a porous medium was numerically analyzed using a non-Darcian model for the momentum equation and energy equations for the wetting and dry zones. In order to show the thermal character of the problem, we assume initially that the porous medium is found at a uniform temperature T0 and suddenly begins the imbibition process into the porous medium with a penetrating fluid at temperature T1. The physical influence of nondimensional parameters such as Peclet number, Pe, effective heat capacity number, beta(w), porous Reynolds number, Re(p), and the inertial coefficient of the porous medium, F, serve us to evaluate the position and velocity of the imbibition front as well as temperature profiles in both zones. In particular, for values of Re(p)F/beta(w)>>1, we recover a type of nonisothermal Washburn law. The numerical predictions show that the imbibition front and the temperature fields strongly depend on the above nondimensional parameters, revealing a clear deviation of the simple Washburn law.

[Serum uric acid and C-reactive protein levels in patients with chronic kidney disease]

Either inflammation or hyperuricemia has been related with increased cardiovascular risk and mortality. A hypothetical relationship between serum uric acid levels (SUA) and inflammatory markers has never been tested in chronic kidney disease (CKD) patients. The purpose of this study was to determine the prevalence of increased C-reactive protein (CRP) levels in CKD patients, and to test the hypothesis of a relationship between SUA and CRP levels. The study group consisted of 337 patients (174 males, mean age 63 +/- 16 years) with advanced chronic renal failure not yet on dialysis. None of them had overt inflammatory or infectious diseases. High sensitivity CRP levels were analyzed as a binary (above or below median value), or continuous variable (log-transformed CRP), by multiple logistic or linear regression analysis, respectively. Demographics, clinical, and biochemical characteristics, including SUA levels, were the variables tested in these analysis. In a subset of 169 patients without diabetes, the same analysis were carried out, with the inclusion of fasting insulin levels and HOMA-IR as independent variables. Median CRP level was 3.25 mg/L, and mean SUA level was 7.59 +/- 1.94 mg/dl. Patients with CRP levels above the median had significantly higher mean SUA level than that of the rest of study patients (7.93 +/- 1.79 vs 7.24 +/- 2.03 mg/dl, p = 0.001). SUA levels correlated significantly with log-transformed CRP levels (r = 0. 16, p = 0.0022). The relationship between SUA and CRP levels remained statistically significant after adjustment for age, sex, comorbid index, obesity, residual renal function, diuretic and allopurinol treatment, in the multivariate logistic and linear regression models (OR: 1.296, p = 0.0003; and beta: 0.204, p = 0.0002). The significant association between SUA and CRP levels did not change when HOMA-IR and fasting insulin levels were included as independent variables in the subset of 169 patients without diabetes. In conclusion, SUA levels are related with CRP levels in CKD patients.

Detachment and diffusive-convective transport in an evolving heterogeneous two-dimensional biofilm hybrid model

Under the hypothesis of correlation between biofilm survival and nutrient availability, by considering fluid drag forces and mortality due to nutrient depletion, a biofilm detachment/breaking condition is derived. The mechanisms leading to biofilm detachment/breaking are discussed. We construct and describe a hybrid model for a heterogeneous biofilm attached to walls in a channel where liquid is flowing. The model is called hybrid because it couples conservation equations with a cellular automaton. The biofilm layer is viewed as a porous medium with variable porosity, tortuosity, and permeability. The model is solved using asymptotic and finite differences methods. Results for porosity, nutrient distribution, and average surface location are presented. The model is capable of reproducing biofilm heterogeneity as well as the typical surface fingering (mushroomlike structure).

Correlation algorithm to recover the phase of a test surface using phase-shifting interferometry

A correlation algorithm to recover the phase in phase-shifting interferometry is presented. We make numerical simulations to test the proposed algorithm and apply it to real interferograms with satisfactory results.

Ronchi test can detect piston by means of the defocusing term

We present simulated results on piston detection applying the classical Ronchi test to a segmented surface. We have found that a piston error in a test segment, induces a change in the transversal aberration, that can be analyzed by mutually comparing the fringes frequency in each segment. We propose that the piston term of the segmented surface can be recovered by geometrically relating the change in transversal aberration with the piston term. To test this, we have simulated some ronchigrams for a known piston error, and we have been able to recover this term for a dynamic range comprised among 57nm and 550 microm. For piston errors > 550 microm a change in the transversal aberration can be appreciated and measured in the ronchigrams although these large pistons are now classical defocusings. Thus we have demonstrated that the Ronchi test can be an alternative method for the piston detection with a large dynamic range.

[Laparoscopic adrenalectomy: our preliminary experience]

INTRODUCTION

In 1992, Gagner described the first laparoscopic adrenalectomy. Since then this technique has been more and more widely employed and several studies confirmed its advantages, comparing to the traditional approach, in terms of reduction of mean hospital stay and therefore of the health expense.

PATIENTS AND METHODS

The Authors' preliminary experience spreads from March to November 2003 when 4 patients were studied and thus underwent a transperitoneal laparoscopic adrenalectomy: 2 of them were affected by Cushing syndrome, 1 by pheochromocytoma in MEN and 1 by an incidentaloma. The transabdominal access in lateral decubitus with 4 trocars was performed.

RESULTS

No complication was reported with a minimal need of analgesic drugs. The mean hospital stay was 4 days and all patients were discharged 48 hours after surgery. The mean diameter of nodules was 40 +/- 30 mm. The definitive histological examination showed 2 cortical adenomas, 1 diffuse cortical hyperplasia and 1 pheochromocytoma.

CONCLUSIONS

This preliminary report confirms the optimal results of other experienced authors. Further interventions will be necessary for improvements and technical requirements.

T-Cell response to self HSP60 peptides in renal transplant recipients: a regulatory role?

T-cell responses to heat shock proteins (Hsp) have been suggested to play a role not only in inflammatory conditions, but also in various human autoimmune diseases and in the allograft response. Previous data from our group suggested that during the early posttransplantation (post-Tx) period (<6 months post-Tx), the anti-Hsp60 T-cell repertoires in renal transplant recipients were predominantly proinflammatory. In the later period, they were predominantly regulatory. In agreement with our results, diversification of the T-cell responses toward the carboxy-terminal determinants of Hsp60, related to the resolution of the inflammatory process, was shown in an experimental model of adjuvant arthritis. It has not been clarified whether this diversification is also present in transplantation. In this context, our objective was to analyze cytokine production against autologous Hsp60 peptides from different regions of the protein, using peripheral blood mononuclear cells of 9 renal transplant recipients at 2 timepoints after transplantation: early (<6 months) and late (>1 year). IFN gamma production induced by Hsp60 peptides was observed in 71% and 75% of the patients in the early and late post-Tx periods, respectively. Interleukin (IL)-10 production induced by Hsp60 peptides was observed in 28% of the patients in the early period and in 62% in the late period. Interestingly, the production of IL-10 was induced mainly by peptides of the intermediate and the C-terminal regions. This suggests a predominance of autoreactive regulatory anti-Hsp T-cell repertoire in the late post-Tx period, which predominantly recognize peptides from the intermediate and C-terminal regions of the protein.

[The surgical treatment of nodular thyroid lesions: our experience. Analysis of 462 cases]

Nodular thyroid lesions are the most frequent endocrine diseases in the general population. The surgical procedure is indicated for nodular thyroid tissue degeneration, or when the suppressive pharmacologic therapy is less efficient, even if sometimes both factors are associated. In Authors' study 462 patients were observed who underwent surgical procedures for thyroid diseases between January 1997-April 2003. In the thyroid pathology, either uninodular or multinodular, the surgical therapy adopted is total thyroidectomy, according to other Authors. The aim of total thyroidectomy is to avoid recurrence and simplify long term pharmacologic treatment. Although the question about the surgical approach (total thyroidectomy vs lobectomy) is still open in the case of single monolateral lesions, on the basis of their experience the Authors believe that the first is the best procedure. For diffused or malignant nodular thyroid pathology, on the contrary, total thyroidectomy is widely adopted.

[Obesity and mortality in advanced chronic renal failure patients]

A protective effect of obesity on the mortality of end-stage renal failure patients has been observed in several studies. Most of these studies have been based on prevalent dialysis population. The aim of the present study was to evaluate if obesity has beneficial effects on the survival of advanced chronic renal failure patients. The study group consisted of 376 patients (mean age 63 +/- 15 years) with advanced chronic renal failure not yet on dialysis. Obesity was defined as a body mass index (BMI) > or = 30 kg/m2. Grade of comorbidity was quantified by the method devised by Davies. Survival was analyzed as time from the referral to the predialysis outpatient clinic to patient death, censoring from contributing additional survival data to the analysis following transplantation. Kaplan-Meier analysis was used to test survival differences according to quartiles of BMI, and between obese and nonobese patients. Further analysis were performed, stratifying survival curves by comorbid scores, lean body mass, age, and sex. Cox proportional hazard regression models were used to investigate the best determinants of mortality, and the role of obesity adjusted for other covariates. Median survival time was 1,453 days. During the follow-up time, 158 patients (42%) died. Survival differences among quartiles of BMI were statistically significant (Breslow = 10.7, p = 0.017). Patients within the lowest and the highest quartiles of BMI had higher mortality than the rest of patients. Survival curves between obese and non-obese patients did not differ significantly. However, when patients without comorbidity were studied apart, those with obesity showed worse survival than the rest of patients (log-rank = 7.42, p = 0.0064). Since the effect of obesity on mortality did not follow a proportional hazard pattern throughout the study period, multivariable analysis for mortality was stratified by 18 months intervals. The variables which fitted the best model were: age (Hazard Ratio: 1.04), comorbid score (HR: 2.17), serum albumin (HR: 0.62), GFR at the study entry (HR: 0.91), male gender (HR: 1.48), and obesity (HR: 1.51). In conclusion, obesity had no survival benefit in patients with advanced chronic renal failure. Obesity had a noteworthy impact on early mortality of advanced chronic kidney disease patients without comorbidities.

[Progression of renal insufficiency in the pre-end-stage renal disease setting]

The rate of decline of renal function (RDRF) in the pre-end stage renal disease setting (pre-ESRD) is highly variable. Several factors have been involved as potential modifiers of renal failure progression. This retrospective study attempts to establish which were the main determinants of the RDRF in pre-ESRD patients followed in the predialysis consult. The study group consisted of 230 patients with pre-ESRD not yet on dialysis who were referred to the predialysis consult from January 1998 to July 2002. The mean follow-up time per patient was 356 days. RDRF was assessed as delta of the average of creatinine and urea clearances (CrCl-UCl). Data obtained at time of referral to the predialysis consult were analyzed as potential predictors of the subsequent RDRF. These independent variables included: demographics, comorbid conditions, main hematological and biochemical data, antihypertensive and statin treatment, mean blood pressure, and CrCl-UCl at time of referral. The predictors of delta CrCl-UCl were determined by multiple linear regression analysis. The determinants of the survival without dialysis were established by the Cox regression hazard model, adjusted to renal function at time of referral. Mean CrCl-UCl at time of referral was 10.98 +/- 2.58 ml/min/1.73 m2, and mean delta CrCl-UCl was -0.37 +/- 0.46 ml/min/1.73 m2/month. Patients with diabetic nephropathy and chronic glomerulonephritis had the fastest RDRF, while patients with ischemic nephropathy and chronic interstitial nephritis had the slowest RDRF. Seventy-five patients (46%) required EPO therapy. The best determinants of delta CrCl-UCl were: the 24-hour proteinuria (p < 0.0001), and the hematocrit at time of referral (p = 0.0024). The best determinants of the survival rate without dialysis during the study period were: the proteinuria (in g/24 hours) (R 1, 16; p < 0.0001), the hematocrit at time of referral (OR: 0.88; p < 0.0001), the treatment with EPO (OR: 0.59; p = 0.02), and the diagnosis of diabetes mellitus (OR: 1.59; p = 0.01). In conclusion, apart from the rate of proteinuria, which could represent the best marker of the RDRF in chronic renal diseases, the development of anemia was associated with faster decline in renal function.

[Differences between the glomerular filtration rate estimated by the MDRD equation and the measurement of creatinine and urea clearance in unselected patients with terminal renal insufficiency]

From the results of the Modification of Diet in Renal Disease (MDRD) study, a prediction equation for a more accurate estimate of glomerular filtration rate (GFR), was developed. The present study ais to compare the GFR estimated by MDRD formula and that calculated by the average of creatinine and urea clearances in unselected patients with advanced renal failure. The study group consisted of 320 (163 males) with advanced renal failure not yet on dialysis. Their mean age was 63 +/- 14 years. Diabetic nephropathy was the most common etiology of renal failure (25%). Significant comorbidity was observed in 115 patients. Serum creatinine (Cr), urea and albumin were determined in all patients. Creatinine (Ccr) and urea clearance (Cu) were calculated on a 24-hour urine collection. The GFR was estimated by summing Ccr and Cu, and dividing by two (Ccr-Cu). THe clearances were corrected for a body surface area of 1.73 m2. The MDRD formula for the estimation of GFR included the following parameters: serum Cr, BUN, age, gender and serum albumin. Linear regression analysis and Bland-Altmann plot were utilized to establish the degree of correlation and agreement between both estimations of GFR. The percent differences between the two estimations of GFR was especially analyzed in those subgroups of patients which were not included in the MDRD study (patients older than 70 years, diabetics and those with comorbid conditions). The mean GFR estimated by Ccr-Cu and by MDRD formula were 10.04 +/- 3.10 ml/min and 10.55 +/- 3.60 ml/min, respectively (p < 0.0001). The two parameters correlated significantly (R = 0.76, p < 0.0001). GFR by the MDRD formula tended to overestimate the highest values of Ccr-Cu. The mean percent difference between both methods was 6.5 +/- 23.6. MDRD predictive equation overestimated significantly Ccr-Cu in patients older than 70 years (mean overestimation of 15%), males (10%), diabetics (10%), and mainly in patients with comorbidity (17%). In conclusion, the GFR estimated by MDRD formula is very similar to Ccr-Cu in young uremic patients without comorbidity. However, major discrepancies between these two methods could be observed in older patients, and mainly in those with comorbidity.