First Report of Mature Citrus Trees Being Affected by Fusarium Wilt in Tunisia

Citrus is an important crop in Tunisia and over 98% of trees of all varieties are grafted on sour orange rootstock. Since September 2010, unusual wilt symptoms have been observed in Takilsa, Bni-Khaled, and Manzel Bouzalfa fields that eventually caused tree death. The disease was observed on 10- to 25-year-old trees of sweet orange (Citrus sinensis) 'Washington Navel' and on 'Clementine' tangerines (C. tangerina) 'Cassar,' 'Hernandina,' and 'MA3,' all grafted on sour orange (C. aurantum) 'Bigarade Gou Tou.' The most conspicuous symptoms were wilting of sections of the canopy, chlorosis and epinasty of young leaves, and discoloration of vascular tissue. No root rot was observed. The problem was widespread with a disease incidence of 45 to 67%. Similar symptoms were described by Timmer et al. (2) on Mexican lime (C. aurantiifolia) nursery plants and some other species of citrus. Three representative isolates of Fusarium oxysporum Schlechtend.:Fr. from crown were single-spored and identified by the production of characteristic, three- to five-celled, sickle-shaped macroconidia with foot-shaped basal cells, ellipsoid microconidia borne in false heads on short monophialides, and chlamydospores in culture (1). The internal transcribed spacer (ITS) region of rDNA and the elongation factor (TEF 1-α) were amplified with primers ITS1/ITS4 and (TEF1/TEF2), respectively. GenBank accessions of ITS region are KC282838, KC282839, and KC282840, for TEF 1-α region are KF531633, KF537336, and KF537337, showed 99% homology with isolates of F. oxysporum in Fusarium-ID data. Pathogenicity tests were conducted on 7-month-old seedlings of sour orange using 10 plants for each of the three isolates. Prior to inoculation, roots were scraping with a sterile scalpel and plants were dipped in a conidial suspension of F. oxysporum (10⁶ conidia ml^-1) for 10 min. Each seedling was planted in a separate pot containing 0.7 liter of sterile soil. Non-inoculated plants with scraped roots dipped in sterile distilled water served as controls. Plants were irrigated and placed in a greenhouse at 24 ± 2°C and 12-h photoperiod. One month after inoculation, leaf chlorosis was observed and 2 months later, 90% of inoculated plants presented a severe wilt. Symptoms on infected plants were similar to those observed in the field. F. oxysporum was successfully re-isolated from the stems, thereby completing Koch's postulates. Genomic DNA was isolated from the re-isolations and PCR amplification of the ITS region was performed with the same primers. There was 100% nucleotide identity with sequences of the original isolates. To our knowledge, this is the first report of fusarium wilt of citrus trees in Tunisia. The pathogen may represent a new form species because previously, the disease was only reported from lime and lemon. References: (1) J. F. Leslie and B. A. Summerell. Page 256 in: The Fusarium Laboratory Manual. Blackwell Publishing Professional, Hoboken, NJ, 2006. (2) L. W. Timmer et al. Phytopathology 72:698, 1982.

Risk factors and consequences of delayed graft function

The impact of delayed graft function (DGF) on the outcome of renal transplantation remains controversial. We analyzed the risk factors for DGF and its impact on graft and patient survival. A total of 354 renal transplants performed between June 1986 and April 2000 were analyzed. Variables analyzed included donor and recipient age, method and duration of renal replacement therapy, HLA mismatch, cold and warm ischemia times, biopsy-confirmed acute rejection, length of stay in the hospital, serum creatinine at the end of first hospitalization as well as graft and patient survival at one, three, five and ten years. The study patients were divided into two groups: patients with DGF (G1) and those without DGF (G2). DGF occurred in 50 patients (14.1%), and it was seen more frequently in patients transplanted from deceased donors (60% vs. 40%, P <0.0001). The cause of DGF was acute tubular necrosis, seen in 98% of the cases. Univariate analysis showed a statistically significant difference between the two groups G1 and G2 in the following parameters: average duration on dialysis (52.3 vs. 36.4 months, P = 0.006), HLA mismatch (44.9% vs. 32.11% P = 0.015), donor age (35.9 vs. 40.2 years, P = 0.026), cold ischemia time (23 vs. 18.2 h, P = 0.0016), warm ischemia time (41.9 vs. 38.6 mn, P = 0.046), length of stay in the hospital during first hospitalization (54.7 vs. 33.2 days, P <0.0001), serum creatinine at the end of first hospitalization (140 vs. 112 μmol/L, P <0.0001) and at three months following transplantation (159 vs. 119 μmol/L, P = 0.0002). Multivariate analysis revealed the following independent risk factors for DGF: deceased donor (RR = 13.2, P <0.0001) and cold ischemia time (RR = 1.17, P = 0.008). The graft survival at one, three, five and ten years was 100%, 93%, 88.3% and 78.3% in G1 versus 100%, 95.9% 92.8% and 82.3% in G2; there was no statistically significant difference. The patient survival at one, three, five and ten years was 100%, 91.3%, 83.6% and 74.4% in G1 versus 100%, 95.9%, 94% and 82.6% in G2 with a statistically significant difference (P = 0.04). Prolonged cold ischemia time and transplantation of kidneys from deceased donors were the main risk factors for DGF in our study. Also, DGF significantly affected patient survival but had no influence on graft survival.

Urinary tract infections following renal transplantation: a single-center experience

Urinary tract infection (UTI) is the most frequent infectious complication among renal transplant recipients and a frequent cause of bacteremia, sepsis and acute graft failure. To evaluate the incidence, risk factors, type of pathogens and long-term effect of UTIs on graft and patient survivals in our center, we performed a retrospective cohort study reviewing the medical records of patients who received a renal transplant at our center from June 1986 to December 2009, excluding patients who lost their grafts in the first month due to arterial or veins thrombosis and acute antibody-mediated rejection. We studied 393 kidney-transplanted recipients; at least one UTI occurred in 221 (53.69%) patients during the follow-up period. The most frequent pathogens isolated in urine culture were Escherichia coli (n = 39, 18.4%) and Klebsiella pneumonia (n = 31, 14.6%). When patients with UTIs were compared with those without UTIs, female gender and use of mycophenolate mofetil or azathioprine seemed to be risk factors for UTIs on univariate analysis. However, female gender was the only independent risk factor on multivariate analysis RR = 1.964 (1.202-3.207), P = 0.007. This study confirmed that UTIs remain a major problem in renal transplant recipients, and female gender was the only independent risk factor.

[Ileocolic intussusception from metastatic renal cell carcinoma]

The lung, the liver, the bone tissue and the brain are the most frequent sites for renal cell carcinoma metastasis. Small bowel metastasis from renal cell carcinoma is rare, with only few cases published. We report the case of ileal metastasis from operated kidney cancer revealed by ileocolic intussusception and causing intestinal obstruction in a 32-year-old woman.

[Acute tubular necrosis in kidney transplantation]

BACKGROUND

The acute tubular necrosis (ATN) is common after kidney transplantation. Acute tubular necrosis (ATN) is multifactorial and represents one of the main causes of the delayed graft function. Its impact on graft and patients survival is documented.

AIMS

To study the prevalence of the ATN in kidney transplanted patients, the acute rejection rate and their impact on the graft and the patient survival.

METHODS

We retrospectively studied the frequency of ATN, its causes and its impact on patient and graft survival in 255 kidney transplanted patients between 1986-2006.

RESULTS

Thirty-nine patients had ATN (15.29%). They are 25 men and 14 women with mean age of 30.1 ± 12.6 years (8-61) followed for an average of 98 ± 61.76 months. The majority was treated by hemodialysis (79.48%) and half of them were transplanted from kidney of deceased donor. All patients received anti lymphocyte serum and the majority anticalcineurins (69.23%). The outcome was favorable in 26 patients (66.66%) with recovery of diuresis and normalization of renal function after 6 weeks on average. An acute rejection was diagnosed in 21 patients (53.48%). The mean creatinine at 1, 5 and 10 years was 135.3, 159.9 and 121.4 μmol / l. Eight patients had creatinine ² 130 μmol / l at 10 years. Ten patients died from infectious and cardiovascular causes. By comparing the 2 groups ATN + and ATN - we found a statistically significant correlation between ATN and cold ischemia (10 ± 10.9 vs 1.2 ± 4.7 hours, p <0.0001) and the interval between the start of dialysis and transplantation (42.18 ± 38.44 vs. 31.1 ± 25.2 months, p= 0.02). No statistical correlation was found between the ATN and gender, age of recipient and donor, warm ischemia, acute rejection, chronic rejection and graft and patient survival at 1, 5 and 10 years.

CONCLUSION

The ATN is more common among transplanted patients from deceased donors. It had good evolution in the majority of cases and it's correlated to cold ischemia and duration of dialysis. Finally, it has no impact on patients and graft survival.

[Cardiac metastasis of renal cell carcinoma, a rare location]

The renal carcinoma is situated in the third rank of the urologic cancers. It is metastatic in a third of the cases, when we made the diagnosis of the cancer. Lungs, bone, the liver, the suprarenal gland and the brain stay metastatic sites of preference. Some metastatic locations are anecdotal and made the object of some publications. We report the case of a cardiac metastasis of renal carcinoma at an old patient 81 years old operated for cardiac tumor.

Short- and long-term outcomes of living donors in Tunisia: a retrospective study

Despite initiatives to increase cadaveric donation, there is still a shortfall in donor organs. Kidneys from living donors now makes a significant contribution to increasing the number of organs available for transplantation in Tunisia. We performed a retrospective study of 405 kidney transplantations, including 321 (79.3%) from living donors performed from June 1986 to December 2007. We obtained information on only 162 (50.4%), namely, 64 men (39.5%) and 98 women (60.5%), whose mean age at the time of donation was 42.3 ± 12.2 years. Twelve (8.22%) perioperative complications occurred: wound infections (n = 4), pneumothorax (n = 4), phlebitis (n = 1), hematomas (n = 2), and urinary infection (n = 1). The mean follow-up period was 117.4 ± 74.4 months. Hypertension occurred in 42 donors (25.9%) with mean values of 134 ± 20 for systolic and 79 ± 10 for diastolic blood pressure. Twelve donors (7.4%) developed proteinuria (mean proteinuria, 0.08 ± 1.25 g/d). Renal insufficiency was found in 28 donors (19.44%), 2 of whom developed chronic renal failure requiring dialysis at intervals of 36 and 84 months. In both cases, we diagnosed a familial form of focal segmental glomerulosclerosis. Two donors (1.2%) died within 10 years after kidney donation due to senility. The relatively favorable outcomes suggest that living-donor kidney transplantation is an acceptable approach, in view of the superior results it yields in recipients. However, efforts to increase the number of cadaveric donors in Tunisia should be made. It is also important to develop a registry of long-term kidney function after kidney donation.

The role of generics in kidney transplant: mycophenolate mofetil 500 versus mycophenolate: 2-year results

OBJECTIVES

The introduction of mycophenolate mofetil has proven itself effective in preventing acute rejection in renal transplant recipients. However, this cost is ineffective with countries with a limited income. This study sought to compare the clinical and therapeutic profiles of a generic formulation with mycophenolate mofetil.

MATERIALS AND METHODS

This 2-year, single-center, prospective, randomized, open-label study investigated the efficacy and safety of a new mycophenolate mofetil generic formulation compared with mycophenolate renal transplant recipients. The study divided patients in 2 groups: 8 patients in G1 received mycophenolate mofetil 500 and 10 patients in G2 received mycophenolate. Their demographics were similar: mean age, 36.6±7.1 and 33.3±11.7 years; sex M/F: 2/6 and 5/5; mean donor age, 42.6±11.1 and 43.6±13.9 years; mean HLA mismatches, 2.7±1.2 and 3.3±1.5; deceased donors, 25% and 20%; and warm ischemia time, 40.2±11.9 and 38.7±10.5 minutes. All patients received 2 g daily of mycophenolate mofetil 500 or mycophenolate with initial dosage of 0.1 mg/kg/d and prednisolone.

RESULTS

One patient of 7 in the mycophenolate mofetil group and 4 of 6 in the mycophenolate group had 1 episode of acute tubular necrosis, and 1 patient in each group had an acute rejection with no significant differences between the groups. The area under the curve of the mycophenolate mofetil did not show any difference between the 2 groups. The values of serum creatinine were also comparable. Patient survival rate at 6, 12, and 24 months was 100% in the groups. The frequencies of digestive and hematologic adverse effects were comparable in the groups with no significant differences.

CONCLUSIONS

Use of mycophenolate mofetil 500 provided safe and effective immunosuppressive therapy compared with mycophenolate. However, as the duration of the study was short, these results need to be confirmed in a long-term study.

[IL1/IL1 Ra, CTLA-4 and Apo1/Fas genes polymorphisms and susceptibility to IgA nephropathy in Tunisian patients]

BACKGROUND

The IgA nephropathy (IgA-N) is considered the most common form of primary glomerulonephritis and its pathogenic mechanisms are very complex. The study of several genes which encode for immunoregulator molecules in inflammatory and immunological responses during the disease, allowed to describe some number of polymorphisms would be involved in the molecular expression, the road marking, the synthesis and\or the binding to the receptors. So an abnormality of the molecular function associated with its polymorphism would be suggested in the genetic predisposition to the disease.

AIM

To determine interleukin 1 (IL1), interleukin1 receptor antagonist (IL1 Ra), CTLA-4 and Apo1/Fas genes polymorphisms frequencies in IgA-N in order to estimate the impact of these polymorphisms in the disease susceptibility.

METHODS

The polymorphism of a single nucleotide (SNP) at (-889) IL1 a of 21 IgA-N patients and 100 healthy blood donors, as controls, was studied by PCRSSP. The SNPs of the IL1 ß (+3954), CTLA-4 (+49) and l'Apo1/Fas were analyzed by PCR RFLP and finally the polymorphism of the IL1 Ra gene was determined by a PCR VNTR (variable number tandem repeat).

RESULTS

Investigation of IL1a/ß and Apo1/Fas polymorphisms showed no differences in genotypes and alleles frequencies between IgA-N patients and controls. However, genotype AA of CTLA-4 exon1 (+49) was significantly higher in patients (47.62%) than in controls (9.1%) p<0.001. Nevertheless, the clinical, histological and biological characteristics of IgA-N were similar in AA CTLA-4 genotype patients compared to AG or GG genotype patients. We fund also, a significant increased frequency of 1/1 IL1 Ra genotype in IgA-N patients (95.24%) compared to controls (54%) (p<0.001) (p<0.001).

CONCLUSION

We conclude that the susceptibility to IgA-N seems to be associated with the presence of CTLA-4 AA and IL1 Ra 1/1 genotypes in Tunisian population. However, the lack of association between IL1 a/ß and Apo1/fas genes polymorphisms should be further investigated by large population based studies.

Kidney transplantation: Charles Nicolle Hospital experience

The aim of our retrospective study was to analyze the short- and long-term follow-up of 298 renal transplantations performed between June 1986 and May 2005. All were first transplantations except 4 cases, with 54 from cadaveric and 244 from living donors. The recipients included 196 males and 102 females of overall mean age of 31.21 +/- 8.9 years (range, 16-61 years). A combination of prednisolone and azathioprine was presented for 212 patients or mycophenolate mofetil for 86 patients. Polyclonal or monoclonal antibodies were used as induction therapy in 183 cases. Cyclosporine was administered to 188 cases and tacrolimus only to 16. HLA matching was 0 mismatches (MM) in 65 cases; 1 or 2 MM in 113; 3 MM in 99; and > or =4 MM in 21. Acute tubular necrosis occurred in 45 cases. One hundred eighteen patients experienced at least 1 acute rejection episode: 102 cases (41.8%) among living and 16 (29.6%) among cadaveric kidneys donor (P = .0007). The actuarial patient and graft survival rates at 1, 5, 10, 15, and 20 years were 95.9%, 87.4%, 77.5%, 65.6%, and 60.8%, and 94.9%, 84.5%, 75.4%, 65.4%, and 53%, respectively. Sixty-three patients died and 72 patients returned to dialysis. Our results were comparable to experienced centers. However, the member of kidney transplantations does not match the increased number of patients on renal replacement therapy. It is advisable to promote obtaining organs from brain-dead donors.

Renal histopathological lesions after lung transplantation in patients with cystic fibrosis

We have analyzed the evolution of renal status beyond the perioperative period in patients with cystic fibrosis (CF) undergoing lung transplantation and presented histological analysis of 15 patients biopsied for an episode of accelerated renal function loss (RFL). Episodes of accelerated RFL after the perioperative period occurred in 32.5% of patients and significantly raised the risk of end-stage renal disease (ESRD) (p < 0.001). The histologic lesions associated with these episodes differed according to the time of onset. Early onset (10 cases) was associated with tubulointerstitial lesions in the form of oxalate nephropathy (50%) and/or a pigmented tubulopathy (80%). This latter was correlated with treatment with antiviral agents (p = 0.002) and aminoside and glycopeptide antibiotics (p = 0.03) administered in the month preceding biopsy. Lesions in late episodes of accelerated RFL (5 cases) were principally vascular: arteriosclerosis and arteriolosclerosis (p = 0.007, p = 0.00002), correlated with diabetic glomerulosclerosis or focal segmental glomerulosclerosis in the absence of prominent diabetic changes. Specific calcineurin-inhibitor nephrotoxicity was present in 93.3% of biopsies associated with thrombotic microangiopathy in 46.7% of cases. The identification of specific etiologies of progressive kidney disease in patients with CF after lung transplantation should permit more effective post-transplant care of these patients.

Avascular osteonecrosis after renal transplantation

Avascular osteonecrosis (AVN) is a serious osseous complication after renal transplantation. Its prevalence clearly decreased from 20% to 4% after introduction of cyclosporine and reduction of steroid doses. The aim of our study was to evaluate the frequency of AVN among kidney transplant recipients and to determine the risk factors by comparing them with a population without AVN. Among 326 kidney transplant recipients between June 1986 and December 2004, 15 patients developed AVN with mean age of 40.86 years, including 11 men and 4 women. Fifteen kidney transplant recipients without AVN were selected to be matched for age, gender, and date of transplantation (control group). Cases of symptomatic AVN were diagnosed by hip X-ray, radioisotope bone scan, or magnetic resonance imaging. AVN was diagnosed at a mean of 3.5 years after transplantation (range, 0.5-13 years). The main localization of AVN was the femoral head in 12 cases and the femoral condyle in 3 cases. We studied the following risk factors: the type of donor (cadaver or living donor), the duration on dialysis before transplantation, the cumulative steroid dose, the acute rejection rate, and the posttransplantation weight gain. Statistical analysis showed that the cumulative steroid dose and the acute rejection rate were higher among the AVN group than the control group (P=.04 and P=.058, respectively). The prevalence of AVN in our population is 4.6%, which is probably an underestimate since these were symptomatic cases. The reduction or early withdrawal of steroids remains the only efficient preventive treatment for AVN.

[Treatment of uremic patients by automated peritoneal dialysis: study of 78 cases]

BACKGROUND

Automated peritoneal dialysis has been increasingly used in recent years. The quality of life is improved in patients on automated peritoneal dialysis with more time for work, family and social activities compared to patients on continuous ambulatory peritoneal dialysis.

AIM

We report our experience concerning patients on continuous ambulatory peritoneal dialysis.

METHODS

From July 1997 to June 2003, we review retrospectively 78 patients with chronic renal failure treated by automated peritoneal dialysis. Tenckhoff catheter was used for all patients with 1 cuff in 39 cases (35.5%) and 2 cuffs in 71 cases (64.5%).

RESULTS

There were 46 males and 32 females. Their mean age was 38.6 +/- 14.5 years. Their main nephropathies were glomerular in 23 patients (29.%), diabetic in 20 patients (25.6%) and vascular in 19 patients (24.4%). Among the 78 patients, 61 (78.2%) were autonomous while 17 (21.8%) were assisted by a member of their family. The mean period of therapy was 25.5 months (3 to 61 months). Peritonitis was the main complication, it was observed in 45 cases after a mean delay of 17 months (1 to 38 months). The mean rate of peritonitis was 36.5 months/patient. Their etiology was identified in 21 (46.7%) cases (8 septic manipulations of catheter and 13 tunnel infections). The principal organism isolated in peritoneal fluid were 18 gram-positive cocci (13 staphylococcus aureus, 4 coagulase-negative staphylococci, 1 streptococcus) and 10 gram-negative bacilli. The outcome of peritonitis was favourable in 39 cases (86.7%). The actuarial technique survival at 1, 3 and 5 years was respectively 94.6%, 80.1% et 49.3%. The actuarial patient survival at 1, 3 and 5 years was respectively 93.3%, 76.8% et 52.2%. At the end of the study, 43 patients (56.4%) left the automated peritoneal dialysis program: 22 (28.2%) were shifted to hemodialysis, 15 (19.3%) died, 6 (7.7%) were transplanted and 1 patient (1.3%) was shifted to continuous ambulatory peritoneal dialysis.

CONCLUSION

Our experience concerning automated peritoneal dialysis is recent with a small number of patients. Our results were acceptable and we have to encourage and extend automated peritoneal dialysis to the most new patients with end-stage renal failure.

Impact of initial blood pressure on the mortality of diabetics undergoing renal replacement therapy

The aim of this study was to determine the blood pressure (BP) profiles and their impact on mortality among a cohort of uremic diabetics treated by hemodialysis. The studied population includes all type II diabetics starting hemodialysis for end-stage renal disease between 1990 and 1996. There were 221 patients (144 men, 77 women) aged from 37 to 78 years, were all followed until death or December 2003 without any censored data. Survival analysis to identify predictors of death was performed using the actuarial method, Cox proportional model, including systolic, diastolic, mean, and pulse blood pressures (SBP, DBP, MBP, PP). One hundred seventy-eight patients (80.5%) were hypertensive at the start of dialysis. Hypertension preceded the diagnosis of diabetes in eight cases (4.5%); 154 patients (86.5%) received antihypertensive drugs and only 23 (14.9%) had well-controlled hypertension. Our population was subdivided into four groups according to their BP levels at the time of beginning of dialysis; G1 (19.5%): normal BP (SBP [90 to 140] and DBP [60 to 90]); G2 (30.3%): Hypertension stage 1 (SBP [140 to 160] and/or DBP [90 to 100]); G3 (32.1%): hypertension stage 2 (SBP [160 to 180] and/or DBP [100 to 110]); G4 (18.1%) hypertension stage 3 (SBP [180 to 220] and/or DBP [110 to 120]). Mean age and comorbidities were similar among the four groups. During a cumulative follow-up period of 872 patient-years, 191 patients died, representing a rate of 21.9 per 100 patient-years; 20.42% of these deaths occurred during the first 3 months of dialysis. Normotensive patients showed lower survival rates without any significant difference in comparison with those of other hypertensive groups. None of the initial BP parameters (SBP, DBP, PP, MBP, hypertension stages) seemed to influence early or global mortalities, which were rather related to the urgent onset of renal replacement therapy, to age, to serum albumin, and to the score of associated morbidities. We conclude that mortality of our hemodialyzed diabetics was not influenced by the blood pressure parameters recorded at the onset of dialysis.