Comprehensive molecular classification of localized prostate adenocarcinoma reveals a tumour subtype predictive of non-aggressive disease.

Background: Management of localized prostate cancer (PCa) is a major clinical challenge since most of these cancers would not evolve but a majority of patients will still undergo a life-changing radical surgery. Molecular studies have shown that PCa can be classified according to their genomic alterations but none of the published PCa molecular classifications could identify a subtype corresponding to non-evolutive tumours. Materials and methods: Multi-omics molecular profiling was carried out on post-radical prostatectomy material from a cohort of 130 patients with localized PCa. We used unsupervised classification techniques to build a comprehensive classification of prostate tumours based on three molecular levels: DNA copy number, DNA methylation, and mRNA expression. Merged data from our cohort and The Cancer Genome Atlas cohort were used to characterize the resulting tumour subtypes. We measured subtype-associated risks of biochemical relapse using Cox regression models and survival data from five cohorts including the two aforementioned. Results: We describe three PCa molecular subtypes associated with specific molecular characteristics and different clinical outcomes. Particularly, one subtype was strongly associated with the absence of biochemical recurrence. We validated this finding on 746 samples from 5 distinct cohorts (P = 3.41 × 10-8, N = 746 tumour samples), and showed that our subtyping approach outperformed the most popular prognostic molecular signatures to accurately identify a subset of patients with a non-evolutive disease. We provide a set of 36 transcriptomic biomarkers to robustly identify this subtype of non-evolutive cases whose prevalence was estimated to 22% of all localized PCa tumours. Conclusion: At least 20% of patients with localized PCa can be accurately predicted to have a non-evolutive disease on the basis of their molecular subtype. Those patients should not undergo immediate surgery and rather be placed under active surveillance.

Association study of MICA-TM and HLA-class I polymorphism with uveitis in South Tunisian population.

BACKGROUND: Uveitis refers to intraocular inflammation. The pattern of uveitis is largely influenced by a multitude of factors including genetic background. AIM: The purpose of our study was to identify the association between the polymorphism of the transmembrane region of MICA (MICA-TM) and uveitis in Tunisian patients with intraocular inflammation. PATIENTS AND METHODS: A total of 79 Tunisian patients and 123 healthy controls were enrolled in our study. HLA-class I phenotyping was performed by microlymphocytotoxicity complement dependent and MICA-TM was genotyped by a semiautomatic fluorescent-labelled PCR method, amplicons were analysed on ABI Prism 310 genotyper. Comparisons of allele frequencies between patients and controls, and between patients' subgroups were performed using SPSS 20.0. RESULTS: In our 79 patients, HLA-B27 showed a significant increased frequency when compared with healthy controls (P=0.003, 7.88 [95% IC=2.17-28.65]). The association was more significant when considering idiopathic anterior uveitis (P=0.00002, OR=11.65 [95% IC=3.06-45.17]). No MICA allele was significantly increased in uveitis groups compared to controls. In the idiopathic uveitis group, MICA-A4 was associated with late age of onset of disease (P=0.04). HLA-B51 and MICA-A6 were associated respectively with severe tyndall (P=0.008) and with the presence of synechiae (P=0.007). CONCLUSION: Some clinical features of uveitis may be influenced by specific MICA-TM alleles. In our South Tunisian population, MICA plays a disease modifying role, rather than being an important gene in the susceptibility for developing of uveitis.

[Association of HLA class I antigens with Behçet disease in South Tunisia]. / Étude d'association des antigènes HLA classe I avec la maladie de Behçet dans le Sud tunisien.

PURPOSE: To study antigen HLA class I association with different clinical forms of Behçet's disease in South Tunisian population. PATIENTS AND METHODS: We retrospectively reviewed 129 clinical case patients. All of the patients fulfilled the criteria of the international study group for Behçet's disease, and were followed at the department of internal medicine of the university hospital of Sfax. HLA class I phenotyping was performed by microlymphocytotoxicity complement dependent for our 129 patients and for 123 healthy controls. We used the program SPSS 11.0 to analyse clinical data and to compare HLA class I antigen distribution between these two populations. RESULTS: The study group concerned a total of 129 patients (81 males and 48 females). The mean age at disease onset was of 32 years. HLA-B51 antigen was the only antigen significantly more frequent among patients (24.81%) than controls (9.76%, p=0.002). HLA-B44 was significantly more frequent among patients having familial history of recurrent buccal aphthosis or Behçet disease. HLA-A11 antigen was associated with early disease onset, and HLA-A1 was negatively associated with severe form of the disease (neurological, vascular or ocular manifestations). CONCLUSION: Our study confirmed the HLA-B51 association with Behçet disease. Nevertheless, B51 frequency in South Tunisian patients was lower than that found in other studies regardless of the clinical manifestation.

Polymorphism of the N-acetyltransferase 2 gene as a susceptibility risk factor for antituberculosis drug-induced hepatotoxicity in Tunisian patients with tuberculosis.

SETTING: Antituberculosis drug-induced hepatitis attributed to isoniazide (INH) is one of the most prevalent drug-induced liver injuries. INH is metabolized by hepatic N-acetyltransferase 2 (NAT2) to form hepatotoxins. AIM: To evaluate whether polymorphism of the NAT2 gene was associated with antituberculosis drug-induced hepatotoxicity in Tunisian patients. METHODS: A total of 66 patients with tuberculosis (TB) who received anti-TB treatment were followed prospectively. Their NAT2 genotype was determined using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). We identified three single nucleotide polymorphisms (SNPs); 481C to T (NAT2*5B), 590G to A (NAT2*6A) and 857G to A (NAT2*7B). Univariate analysis and logistic regression analysis were used to evaluate the risk factors of isoniazid-induced hepatitis. RESULTS: Fourteen patients (21.2%) were diagnosed with anti-TB drug-induced hepatitis. None of the rapid acetylators-type patients have expressed serum aminotransferase elevation. Among patients with hepatotoxicity, slow acetylators-type patients had a higher risk of hepatotoxicity than intermediate acetylators (21.4% vs. 78.6%, P=0.01). Statistical analysis revealed that the frequency of a variant diplotypes, NAT2*5B/5B and NAT2*6A/6A, were significantly increased in TB patients with hepatotoxicity, compared with those without hepatotoxicity (P=0.01, odds ratio [OR]=7.6 and P=0.029, OR=15, respectively). By contrast, the frequency of the rapid acetylation NAT2*4 allele was significantly lower in TB patients with hepatotoxicity than those without hepatotoxicity (P=0.02, OR=0.18). Moreover, 590G/G genotype was associated with decreased hepatotoxicity (P=0.01); by contrast, homozygous point mutation at position 481 and 590 were associated with a higher risk of hepatotoxicity (P=0.01). CONCLUSION: Our results suggest that the slow-acetylator status of NAT2 is risk factor for INH-induced hepatotoxicity. Moreover, diplotypes, NAT2*5B/5B, NAT2*6A/6A, 481T/T and 590A/A, are useful new biomarkers for predicting anti-TB drug-induced hepatotoxicity.

Involvement of nitric oxide in corticosterone release and glucose metabolism in food deprived rats.

This study was performed to investigate the involvement of nitric oxide (NO) in corticosterone, endpoint product of hypothalamo-pituitary-adrenal (HPA) axis activation, and metabolic responses to 3 days of food deprivation. To investigate this aim, we used a nonspecific inhibitor of nitric oxide synthases, N-nitro- L-arginine methyl ester (L-NAME). In food deprived group we have noted a significant increase in plasma corticosterone concentration accompanied by a significant depletion in hepatic glycogen content with concomitant increase in glycogen phosphorylase (GP) activity by 63.72%, key enzyme of glycogenolysis and decrease in hexokinase (HK) activity by 25.16%, leading to significant decrease in glucose concentration. However, L-NAME administration in food deprived rats decreased slightly corticosterone level and GP activity (16.39%) and increased HK activity (11.26%) as compared to food deprived group. Considering these results, we can deduce that in food deprivation nitric oxide is involved in the regulation of corticosterone release and in glucose metabolic responses via glycogenolysis activation by the stimulation of GP activity and the inhibition of HK activity. However, more studies are necessary to further clarify the mechanisms by which NO induces these responses.

[Molecular analysis of crossing-over in the CMH in two Tunisian families with aplastic bone marrow]. / Analyses moléculaires de recombinaisons localisées au niveau du CMH dans deux familles tunisiennes.

In order to select compatible human leucocytes antigens (HLA) donors for bone marrow graft, all the members of 76 families were typed by serology for HLA class I (A and B locus) and class II (DR, DQ locus) by polymerase chain-reaction-sequence-specific primes (PCR-SSP). The HLA typing interpretation revealed the existence of crossing-over in major histocompatibility (CMH) regions for two families, AB and AT, with aplastic bone marrow. The study of crossing-over site has needed the genotyping of seven short tandem repeat (STR) markers located on the short arm of chromosome 6 (D6S291, D6S273, TNFa, C1.2.C, C3.2.11, D6S265, D6S276), using ABI Prism 310 sequencer. HLA and STR Haplotypic analysis enabled us to confirm the crossing-over between locus B and DR in AB family and between locus A and B in AT family. Based in this study, we recommend to be careful in the interpretation of the results of HLA typing between donors and recipients of bone marrow. Complementary investigations should be accomplished for studying genetic abnormalities, which would be involved in this pathology.

Vasopressin and nitric oxide synthesis after three days of water or food deprivation.

Nitric oxide has been suggested to be involved in the regulation of fluid and nutrient homeostasis. In the present investigation, vasopressin and nitric oxide metabolite (nitrite and nitrate) levels were determined in plasma of male Wistar rats submitted to water or food deprivation for three days. Hematocrit and plasma sodium showed marked increase in dehydrated and starved rats. Potassium levels and plasma volume decreased in both treated groups. Plasma osmolality and vasopressin levels were significantly elevated in water deprived (362.8 +/- 7.1 mOsm/kg H2O, 17.3 +/- 2.7 pg/ml, respectively, p < 0.001) rats, but not in food deprived (339.9 +/- 5.0, 1.34 +/- 0.28) rats, compared to the controls (326.1 +/- 4.1, 1.47 +/- 0.32). The alterations observed in plasma vasopressin levels were related to plasma osmolality rather than plasma volume. Plasma levels of nitrite and nitrate were markedly increased in both water and food deprived rats (respectively, 2.19 +/- 0.29 mg/l and 2.22 +/- 0.17 mg/l versus 1.33 +/- 0.19 mg/l, both p < 0.01). There was a significant negative correlation between plasma nitrite and nitrate concentration and plasma volume. These results suggest that both dehydration and starvation increase plasma nitric oxide, probably by activation of nitric oxide synthases. The release of nitric oxide may participate in the regulation of the alteration in blood flow, fluid and nutrient metabolism caused by water deprivation or starvation.

Protective effect of resveratrol on ethanol-induced lipid peroxidation in rats.

AIM: Chronic ethanol treatment induces an increase in oxidative stress. As polyphenolic compounds are potent antioxidants, we aimed to examine whether dietary supplementation of resveratrol may attenuate lipid peroxidation, the major end-point of oxidative damage resulting from chronic ethanol administration. METHOD: Three groups of male Wistar rats were used. The first group served as control and received a daily intraperitoneal injection of 0.9% saline. The second group of rats was daily injected with 35% ethanol at 3 g/kg body weight. The third group was given the same dose of ethanol and supplemented with resveratrol (5 g/kg) in the standard diet. Malondialdehyde (MDA), an indicator of oxidative stress, was measured in the liver, heart, brain, and testis. RESULTS: At the end of a 6 weeks treatment period, MDA levels were significantly increased by 51.5, 53.7, 72.7, and 40.5% in the liver, heart, brain, and testis, respectively. However, when ethanol treated rats were given resveratrol the increase in MDA levels was significantly reduced in all organs to nearly those of control rats. CONCLUSION: Resveratrol is able to inhibit the ethanol-induced lipid peroxidation and have protective effect against oxidative injury.

Production and purification of a calcium-dependent protease from Bacillus cereus BG1.

The production and purification of a calcium-dependent protease by Bacillus cereus BG1 were studied. The production of the protease was found to depend specifically on the calcium concentration in the culture medium. This suggests that this metal ion is essential for the induction of protease production and/or stabilisation of the enzyme after synthesis. The calcium requirement is highly specific since other metal ions (such as Mg(2+) and Ba(2+), which both activate the enzyme) are not able to induce protease production. The most appropriate medium for growth and protease production comprises (g L(-1)) starch 5, CaCl(2) 2, yeast extract 2, K(2)HPO(4) 0.2 and KH(2)PO(4) 0.2. The protease of BG1 strain was purified to homogeneity by ultrafiltration, heat treatment, gel filtration on Sephacryl S-200, ion exchange chromatography on DEAE-cellulose and, finally, a second gel filtration on Sephacryl S-200, with a 39-fold increase in specific activity and 23% recovery. The molecular weight was estimated to be 34 kDa on SDS-PAGE. The optimum temperature and pH of the purified enzyme were determined to be 60 degrees C and 8.0, respectively, in 100 mM Tris-HCl buffer + 2 mM CaCl(2).

Evolution of acquired resistance to third-generation cephalosporins in Enterobacteriaceae in a Tunisian hospital 1993-2001.

Between January 1993 and December 2001, the overall frequency of resistance to third-generation cephalosporins in isolates of Enterobacteriaceae from Charles Nicolle Hospital, Tunis, rose from 2.4% to 7.4%. Klebsiella pneumoniae was the most prevalent species (56%), followed by Escherichia coli (15%) and Proteus mirabilis (9%). A rate of 49% was observed among isolates from paediatric patients in 1999, caused mostly by outbreaks in the neonatal intensive care unit of K. pneumoniae and P. mirabilis isolates that produced extended-spectrum beta-lactamases.

Two-year surveillance of antibiotic resistance in Streptococcus pneumoniae in four African cities.

Worldwide spread of antibiotic resistance in Streptococcus pneumoniae is a major problem. However, data from West and North African countries are scarce. To study the level of resistance and compare the situations in different cities, a prospective study was conducted in Abidjan (Ivory Coast), Casablanca (Morocco), Dakar (Senegal), and Tunis (Tunisia), from 1996 to 1997. The resistances to eight antibiotics of 375 isolates were studied by E test, and the results were interpreted using the breakpoints recommended by the National Committee for Clinical Laboratory Standards. Overall, 30.4% of the isolates were nonsusceptible to penicillin G (25.6% were intermediate and 4.8% were resistant). Amoxicillin (96.3% were susceptible) and parenteral third-generation cephalosporins (92.7%) were highly active. Resistance to chloramphenicol was detected in 8.6% of the isolates. High levels of resistance were noted for erythromycin (28%), tetracycline (38.3%), and cotrimoxazole (36.4%). Resistance to rifampin was rare (2.1%). There were significant differences in resistance rates between individual countries. Multiple resistance was more frequent in penicillin-nonsusceptible isolates than in penicillin-susceptible isolates. Recommendations for treatment could be generated from these results in each participating country.

Vasopressin and A1 noradrenaline turnover during food or water deprivation in the rat.

In the present study, we have examined in Wistar rats the effects of food or water deprivation of 3 days on the hypophyso-adrenal axis, vasopressinergic system and activity of A1 noradrenergic brain stem cell group, which is involved in the control of the hypothalamic neuro-endocrine activity. Levels of adrenocorticotropic hormone (ACTH) and vasopressin (AVP) were determined by radio-immunoassay, and corticosterone level was determined by fluorimetric method. Plasma levels of ACTH and corticosterone were greatly increased in both groups of rats. In water-deprived rats, plasma AVP (13.83 +/- 1.63 vs. 3.03 +/- 0.23 pg/ml) and osmolality levels were significantly elevated with a marked decrease of AVP hypophysis content (272 +/- 65 vs. 1098 +/- 75 ng/mg protein), but not in food-deprived rats in which osmolality did not change and AVP remained stocked (2082 +/- 216 ng/mg protein) in the hypophysis without release in the plasma (1.11 +/- 0.23 pg/ml). These observations indicated that both food-deprivation and water-deprivation stimulated the pituitary adrenal axis thereby suggesting a stress state. AVP production is stimulated both by fluid and food restriction but is secreted with differential effects: during food restriction AVP secretion is limited to supporting the hypothalamic pituitary-adrenal system.

[The effect of age and dehydration on the activity of the vasopressinergic system in rats]. / Effet de l'âge et de la déshydratation sur l'activité de l'axe vasopressinergique chez le rat.

The aim of our work was to study the different blood parameters as well as the activity of the vasopressinergic axis in young and mature male rats under normal conditions and following a 3-day dehydration cycle by water deprivation. Under normal conditions, our study demonstrates higher levels of vasopressin in mature rats as compared to young rats. This could be due in part to the higher blood osmolality in the mature rats. After dehydration, hypovolemia, plasmatic hyperosmolality, hypernatremia and hyperproteinemia cause a stimulation in vasopressin synthesis and release, as seen in results obtained from the hypothalamus, hypophysis and plasma in both young and mature rats. However, the response of the vasopressinergic axis to dehydration is greater in young rats, suggesting a more pronounced sensitivity to osmotic factors.

[Infectious endocarditis caused by a glycopeptide-resistant enterococus]. / Endocardite infectieuse a entérocoque résistant aux glycopeptides.

Enterococci are an important cause of infective endocarditis. Their resistance to most of the antibiotics involve real therapeutic problems. We report the first clinical isolate of glycopeptide resistant enterococcus from blood culture of patient with a prosthetic valve endocarditis. The strain is an E. faecium with a high level of resistance to vancomycin and teicoplanin (MIC > 256 mg/l), a low level of resistance to gentamycin (MIC = 6 mg/l) and susceptible to ampicillin (MIC = 1.5 mg/l). Therapeutic failure was observed leading to a surgical treatment. Therapy of such infection caused by multiresistant Enterococcus must be based on the study of bactericidal activity of antibiotic associations. In order to control the spread of this emerging resistance, the implementation of control measures is necessary.

Urolithiasis in Tunisian children: a study of 120 cases based on stone composition.

The composition of urinary stones in children depends on socioeconomic conditions and hygiene, geographical area, and dietary habits. We analyzed urinary stones from 120 consecutive Tunisian children (81 males, 39 females) aged 5 months to 15 years. The stone was located in the upper urinary tract in 91 cases (76%). Stone analysis included both a morphological examination and an infrared analysis of the nucleus and the inner and peripheral layers. The main components of bladder calculi were whewellite (69%) and struvite (22%), whereas the main component of upper urinary tract calculi was whewellite (67%). The nucleus of bladder stones was composed of ammonium urate (45%), struvite (28%), cystine (10%), and carbapatite (7%). The nucleus of kidney and ureteral calculi was mainly composed of ammonium urate (38%), whewellite (24%), carbapatite (13%), or struvite (11%). Based on stone composition, urinary tract infection was involved in the nucleation or growth of a third of calculi. Endemic urolithiasis involving simultaneous nutritional, metabolic, and infectious factors, and defined by its nucleus composed of ammonium urate without struvite, represented 40% of cases. Exclusive metabolic factors - including genetic diseases such as primary hyperoxaluria, cystinuria, and hypercalciuria - were responsible for less than 25% of cases.

Tissue norepinephrine turnover and cardiovascular responses during intermittent dehydration in the rat.

We investigated the central and peripheral sympathetic responses to intermittent dehydration in rats. The norepinephrine (NE) turnover, a biochemical index correlated with noradrenergic neuronal activity, was measured. The modification of blood pressure was also determined by telemetry during the different cycles of dehydration. Dehydration caused a decrease of NE turnover in A2, A5 and A6 nuclei and in peripheral organs. The vasopressinergic level of dehydrated rats decreased in hypophysis and hypothalamus, and increased in plasma. A repeated gradual increase of arterial blood pressure during the first three days of dehydration, followed by a sudden drop when the rats were rehydrated on the fourth day was observed. In conclusion, our study revealed an increase in blood pressure and in central sympathetic activity during dehydration.

Effects of acute and chronic starvation on central and peripheral noradrenaline turnover, blood pressure and heart rate in the rat.

When faced with stress, an organism calls upon several mechanisms to maintain biological homeostasis. The cardiovascular system is the first to respond usually with an increase in arterial pressure and tachycardia. Therefore we investigated the central and peripheral sympathetic responses to acute and chronic starvation in Wistar rats. The noradrenaline (NA) turnover rate was determined in different catecholaminergic nuclei (A1, A2, A5, A6) as well as the arterial blood pressure and heart rate modifications. During acute starvation (3 days of starvation), the NA turnover was increased in the A1 and rostral A2 nuclei as well as in ventricles and kidneys and decreased in the A6 nucleus. During chronic starvation (4 consecutive cycles of 3 days of starvation plus 1 day of feeding), the NA turnover was increased in the A5 and caudal A2 nuclei as well as in ventricles and atria and decreased in the A1 nucleus and kidneys. The arterial blood pressure revealed a gradual decrease during the first 3 days of fasting but the heart rate was not modified. We conclude that starvation should be considered as an unusual state of stress because of the absence of locus coeruleus response (A6 nucleus) despite its well-defined role in stress reactions. One of the manifestations of these central and peripheral noradrenergic changes is the change in blood pressure during the starvation-feeding cycles.

[Colonic tuberculosis: an exceptional cause of a massive surgical hemorrhage apropos of a case and review of the literature]. / La tuberculose colique: une cause exceptionnelle d'hémorragie massive chirurgicale a propos d'un cas et revue de la littérature.

Colonic tuberculosis rarely causes massive bleeding, as a matter of fact less than twenty cases have been reported in medical literature. Resorting to surgery in this context is even more exceptional. We have not found any case operated on in the literature we have consulted. Endoscopy together with histological study of biopsies is the best exam for the diagnosis of this disease. We report the case of a 37 year old male, coronarian, carrying a caecal lesion evocative of tuberculosis at the endoscopic exam, who had an emergency right hemicolectomy for massive bleeding caused by caecal tuberculosis. The surgical indication was dictated by the abundance and the persistence of the bleeding. The post-operative course was uneventful.