Association study of MICA gene polymorphisms with rheumatoid arthritis susceptibility in south Tunisian population

The aim of this study was to investigate the role of major histocompatibility complex (MHC) class I chain-related gene A (MICA) polymorphisms, important in natural killer (NK) cell function, in patients with rheumatoid arthritis (RA). A transmembrane (TM) alanine-encoding GCT repeats, termed A4, A5, A5.1, A6 and A9 in the MICA gene, and single-nucleotide polymorphisms (SNPs): the Met129Val polymorphism (rs1051792) and the nonsynonymously coding SNP (rs1051794) were genotyped in 142 patients with RA and 123 unrelated healthy individuals using, respectively, PCR fluorescent method, nested PCR-RFLP and allele specific PCR (ASP). Association was assessed based on the χ2 test, genotype relative risk (GRR) and odds ratio (OR) with 95% confidence intervals (CIs). Our results show a trend of association of the different MICA genotypes G/G, G/A and A/A (P = 0.029) which did not attain the significance after Bonferroni's correction (pc = 0.08). Although, we revealed a significant association of the genotype A/A of MICA-250 in patients with RA compared to healthy controls (pc = 0.033). In contrast, no significant differences between alleles and genotypes frequencies were found either with MICA-TM or MICA met129 val (P > 0.05) in our sample. Moreover, stratification of patients with RA according to clinical and immunological data for the different polymorphisms studied shows a significant association of both MICA-250 G allele (pc = 0.0075) and MICA-250 GG genotype (pc = 0.008) and both allelic (val) (pc = 0.021) and genotypic (val/val) distribution (pc = 0.0095) for MICA met129 val in the RF-positive subgroup compared to RF-negative patients with RA. In contrast, we found a strong association of the MICA-TM A9 allele in RF-negative patients with RA (pc = 0.0003). This study indicates the involvement of the MICA-250 polymorphism in the genetic susceptibility and severity to RA and suggests that variations in MICA-TM and MICA met129 val may have an effect on RA severity in our south Tunisian sample.

Additive effect of diets and training on total insulin-like growth factor-1 (IGF-1) in rats

OBJECTIVES

Although it is known that circulating levels of insulin-like growth factor-1 (IGF-1) are influenced by both physical exercise and dietary intake separately, there is little information regarding the additive effect of diets and training on IGF-1 regulation. To test this, we examined the combined effect of 30 days of two different diets (high-protein and high-carbohydrate) and exercise training on total IGF-1.

MATERIALS AND METHODS

The study was carried out with four groups of rats; the sedentary group with standard diet (SS) (control group), standard diet with exercise (SE), high-protein diet with exercise (PE) and high-carbohydrate diet with exercise (CE). Serum IGF-1, insulin, corticosterone were analyzed.

RESULTS

IGF-1 concentrations were decreased by exercise training (p<0.001) and only with protein diet (p<0.05). Physical training, with and without diet, decreased body weight and food intake (p<0.01) and increased corticosterone levels (p<0.05). Carbohydrate diet did not cause major hormonal and metabolic alterations.

CONCLUSION

The main result of this study was the decreased levels of IGF-1 in spite of high-protein diet, which is known to enhance IGF-1 secretion, and the little changes with carbohydrate diet. This may be related to the negative energy balance as a result of the catabolic state induced by exercise training and decreased calorie intake in protein diet. Thus, it can be concluded that the caloric restriction, regardless of dietary composition, decreased IGF-1 secretion.

MHC class I and class II genes in Tunisian patients with reactive and undifferentiated arthritis

OBJECTIVE

To study HLA class I and class II association in Tunisian patients with reactive (ReA) and undifferentiated arthritis (UA).

METHODS

The study included 17 patients with ReA defined according to the European Spondylarthropathy Study Group criteria for spondylarthropathy (SpA), 11 patients classified as having undifferentiated arthritis and 100 unrelated healthy controls. HLA class I antigens were typed serologically and HLA class II alleles were genotyped molecularly by the polymerase chain reaction with sequence-specific primers technique.

RESULTS

There was a major difference between HLA alleles in ReA and UA patients when compared separately with controls. Increased frequencies of HLA-B27 (p=7.76 10-12, OR=59.30), HLA-B51 (p=0.015, OR=4.91) and HLA-DRB1*04 (p=0.033, OR=2.90) alleles were found in patients with ReA but not in patients with UA. HLA-B27 was not expressed totally in our cohort of UA patients. A significant increase of HLA-B15 (p=0.002, OR=18.40) and a moderate increase of HLA-B7 (p=0.043, OR=5.15) was found in patients with UA, but not in patients with ReA. In the B27 negative patients, HLA-DRB1*04 association with ReA was found independently of B27.

CONCLUSION

Our data confirmed a significant association of HLA-B27 with ReA in the Tunisian population. Our results also suggested that some of the additional HLA antigens were associated with ReA including HLA-B51 and HLA-DRB1*04 alleles. UA seemed to have a genetic background different from ReA in Tunisian patients.

[Bacteriologic profile of bacteremia due to multi-drug resistant bacteria at Charles-Nicolle Hospital of Tunis]

OBJECTIVE

The authors had for aim to evaluate the place of multi-drug resistant bacteria (MDR) in nosocomial bacteremia.

MATERIALS AND METHODS

A retrospective study was carried out at the Microbiology laboratory of Charles Nicolle hospital of Tunis (2001-2003). One hundred and ninety-five isolated MDR [third generation cephalosporin resistant enterobacteria, methicillin-resistant Staphylococcus aureus (MRSA), Acinetobacter baumannii and Pseudomonas aeruginosa resistant to ceftazidime and imipenem]. An automated system was used to detect bloodstream infections. Microorganism identification was performed by conventional methods and antibiotic susceptibilities were determined by the disk diffusion method.

RESULTS

MDR bacteria were resistant to third generation cephalosporins (29%), A. baumannii (24%), P. aeruginosa (24%), and MRSA (10%). ERC3G were resistant to aminosides and fluorquinolones. A. baumannii and P. aeruginosa had high resistance rates. Associated resistance rates in MRSA were moderate.

CONCLUSION

MDR bacteria are of great concern in our hospital. This situation emphasizes the importance to maintain rigorous measures of hygiene as well as adapted antibiotic prescriptions.

Evaluation of a cefoxitin disk diffusion test for the routine detection of methicillin-resistant Staphylococcus aureus

Two oxacillin disk methods were compared with a cefoxitin disk diffusion test for detection of methicillin-resistant Staphylococcus aureus (MRSA), with PCR for mecA as the reference method. When tested with 115 MRSA and 350 methicillin-susceptible S. aureus isolates, the cefoxitin disk test (specificity 100%, sensitivity 96.5%) was superior to the oxacillin disk methods (specificity 99.1%, sensitivity 90.4%). Testing with both oxacillin and cefoxitin disks would give better sensitivity (100%) than the cefoxitin test alone, but at the expense of specificity (99.1%). The cefoxitin disk test required no special test conditions and would improve the reliability of routine tests for detection of MRSA.

Effect of chronic lead exposure on kidney function in male and female rats: determination of a lead exposure biomarker

Several cytotoxic chemical pollutants inducing peroxidative damages are liable to induce kidney failure. Among these pollutants we find heavy metals such as: lead, nickel, cadmium, vanadium and mercury. Lead is one of the most dangerous metals because it is widely spread in the environment, and because it may be a source of several nervous diseases. The aim of this study is to provide evidence concerning the effect of this metal on the renal function and to try to determine a storage corner in the organism which serves as an indicator of a lead intoxication. Lead acetate was administered by oral route in the drinking water to adult rats aged three months at the rate of 0.3% (P1) and 0.6% (P2). Reference rats received distilled water to drink under the same conditions. The treatment continued for 15, 30, 45, 60 and 90 days. The creatinemia, uremia, glycemia and creatinuria are determined by colorimetric techniques. Lead concentration in blood as well as the lead content of the tail are determined by atomic absorption after nitroperchloric mineralization at the liquid stage. The results showed an increase of creatinemia on the 30th day of the experiment for both sexes in (P1 and P2). The same happened for ureamia. The increase of these two parameters would indicate a renal deficiency which is confirmed by a decrease of creatinuria and urinary pH observed mainly on and after the 45th day of the experiment. An increase of the renal relative weight was noticed in P1 and P2 on the 30th day of the treatment. The determination of the concentration of lead in the blood shows that this factor increases among treated subjects in a constant way, independently of the dose and the duration of the treatment. Nevertheless, the rate increase of lead in the tail seems to be dose-dependent. In conclusion, lead administered by oral route causes a renal deficiency to the rat without distinction between males and females. In addition, the tail seems to be a reliable exposure biomarker that demonstrates lead intoxication. The tail seems to be a dosimeter of lead bio-accumulation. It constitutes an endogenous source of lead impregnation. The concentration of lead in the blood is only an indicator of recent exposure.

[Abdominal actinomycosis. Report of three cases and review of the literature]

Actinomyces are Gram positive, anaerobic, filamentous bacteria, saprophytes of the oral cavity and intestinal tract of humans. They rarely cause chronic suppurative infections. Abdominal abscess can masquerade as a malignant process and lead to a surgical intervention with resection. We report three patients with abdominal actinomycosis; the first affected the liver with a favorable outcome on medical treatment, the second of abdomino-pelvic localisation was related to an intra-uterine device and the last affecting the transverse colon simulated a malignant process and required an hemicolectomy. These observations illustrates the difficulties of the diagnosis of this rare and unrecognized disease.

[Pelvic ganglioneuroma. Case report]

Ganglioneuroma is a neurogenic tumor originating from autonomic ganglia. It most commonly occurs in patients younger than 20 years with a slight predominance of females. The pelvic localization is rare. Imaging can lead to diagnosis but it is not specific. The diagnosis can only be confirmed by the pathologic study. The authors report one case of pelvic ganglioneuroma diagnosed in an 11-year-old child who also had hypertension and renal failure.

[Effects of automobile lead on the general growth and sexual activity of the rat]

To identify the active element of automotive exhaust gas responsible for masculine infertility, previously proved by our laboratory, we undertook these experiments. Four hundred young male and female rats were exposed during two months (30 min/d) to three types of automotive exhaust gases. The first type emanated from an engine running on gasoline with lead, the second from an unleaded gasoline engine, the third from a diesel engine. These three engines had the same power (5 horsepower vehicles < 3.5 tons). For the first type of emissions, some lead deposits were found in the lungs by histologic techniques. This gas also induced in male rats the atrophy of the testicle, seminal vesicle and epididym, certain pathological changes in spermatogenesis shown by the histologic study, and a decrease of the serum's testosterone level. In female rats, the relative weights of the ovary and uterus, as well as the percentage of the arrival of oestrus, were not affected by the gaseous treatment. Both the second and third types of gases seemed less active on the masculine sex as far as these parameters are concerned. Our study suggests that, for light vehicles, leaded gasoline pollutes more than unleaded gasoline or diesel fuels, and that the lead present only in the first type would be the active element responsible for the masculine infertility and body weight gain reduction in rats.

[Colon cancer. Study of 153 cases and comparison with a series of 140 historic cases]

The authors study the epidemiological, diagnostic and therapeutic features of 153 consecutive cases of colon cancers collected between 1985 and 1998. They compare the results with those of a previous study performed in the same hospital service (140 cases between 1966 and 1984). It is a series of 79 men and 74 women (sex ratio = 1.07). The mean age was 56.6 +/- 14 years old with 13.7% of the patients who were less than 40 years old. The operability and the resectability were respectively 98.7% and 83.7% with a global operative mortality of 7.9%. According to the Dukes classification, they were 2 A stages, 73 B stages, 32 C stages and 45 D stages. Starting from 1993, 53% of the C stages an 48% of the B stages had an adjuvant chemotherapy. The comparison between our present results and those of our previous series does not show any modification in what regards the mean age, the cancer frequency in young people, the complicated forms proportion and time needed for the diagnosis by comparison to the beginning of symptomatology. The colic cancer prognostic improvement is attained through an earlier diagnosis, making it possible to reduce the developed forms and the complicated forms proportion, the consequence of which is the operative mortality decrease and the log-range survival increase.

[Neuroendocrine carcinoma in Barrett's esophagus. Report of a case]

The neuroendocrine tumours of the oesophagus are exceptional. They are a spectrum of heterogeneous tumours often not clearly defined in the literature. We report a case of moderately differentiated neuroendocrine tumour of the oesophagus arising from Barrett's mucosa in 51-year-old man treated surgically and who was free of disease 28 months after excision. We discuss about this case, the classification, the histogenesis and therapeutic approaches of these tumours.

[Ocular signs of primary hyperoxaluria type I]

PURPOSE

To report the results of ophthalmological examination of 14 patients with primary oxalosis of type I, and to appreciate the diagnostic value of these signs.

MATERIAL AND METHODS

Fourteen patients, 7 girls and 7 boys with an average age of 8-35 years (3 months - 15 years). Ten patients had renal failure, 2 died without dialysis and eight were treated with dialysis; 5 out of 8 had hemodialysis and the duration of this treatment varied between 3 months and 3.5 years, 3 out of 8 had peritoneal dialysis.

RESULTS

Visual acuity was 10/10 in 11 cases and we noted a vision of 5/10 in one eye in one case. Ocular fundus examination was normal in 7 cases. In 5 cases, it showed numerous minute white round flecks at the posterior pole and near the retinal vessels which probably correspond to deposition of calcium oxalate crystals. In one case we found a diffuse retinal pigment atrophy and in another case a sectorial papillar atrophy without loss of vision.

CONCLUSION

This flecked retinopathy can occur before hemodialysis or after a few months or years of hemodialysis. There is no correlation between duration of dialysis and ocular lesions.

[Eikenella corrodens pleuro-pulmonary infection. Apropos of a case]

A case of single bacteria pleuropulmonary infection was observed in a 21-year-old patient with heterozygous sicle-cell amenia. The role of this bacteria in pleuropulmonary suppuration, the pathophysiology and secondary lesions are discussed together with therapeutic modalities.