Two novel CYP11B1 mutations in congenital adrenal hyperplasia due to steroid 11β hydroxylase deficiency in a Tunisian family

Steroid 11β hydroxylase deficiency (11β-OHD) (OMIM # 202010) is the second most common form of congenital adrenal hyperplasia (CAH), accounting for 5-8% of all cases. It is an autosomal recessive enzyme defect impairing the biosynthesis of cortisol. The CYP11B1 gene encoding this enzyme is located on chromosome 8q22, approximately 40kb from the highly homologous CYP11B2 gene encoding for the aldosterone synthase. Virilization and hypertension are the main clinical characteristics of this disease. In Tunisia, the incidence of 11β-OHD appears higher due to a high rate of consanguinity (17.5% of congenital adrenal hyperplasia). The identical presentation of genital ambiguity (females) and pseudo-precocious puberty (males) can lead to misdiagnosis with 21 hydroxylase deficiency. The clinical hallmark of 11β hydroxylase deficiency is variable, and biochemical identification of elevated precursor metabolites is not usually available. In order to clarify the underlying mechanism causing 11β-OHD, we performed the molecular genetic analysis of the CYP11B1 gene in a female patient diagnosed as classical 11β-OHD. The nucleotide sequence of the patient's CYP11B1 revealed two novel mutations in exon 4: a missense mutation that converts codon AGT (serine) to ATT (isoleucine) (c.650G>T; p.S217I) combined with an insertion of a thymine at the c.652-653 position (c.652_653insT). This insertion leads to a reading frame shift, multiple incorrect codons, and a premature stop in codon 258, that drastically affects normal protein function leading to a severe phenotype with ambiguous genitalia of congenital adrenal hyperplasia due to 11β hydroxylase deficiency.     

Containment of Local COVID-19 Outbreak Among Hematopoietic Stem Cell Transplant Recipients and Healthcare Workers in a Pediatric Stem Cell Unit

Journal of Clinical Immunology -     

Evaluation of the renal function in type 2 diabetes: clearance calculation or cystatin C?

Screening for diabetic nephropathy is usually done by albuminuria/24h and the use of creatinine clearance. The objective of this study was to evaluate the renal function in Type 2 diabetes by using different formulas of creatinine clearance and to assess the contribution of cystatin C; 83 adults with type 2 diabetes (23 men and 60 women) and 83 adult controls (40 men and 43 women) were studied. Biochemical parameters were determinated on Coba 6000? (Roche diagnostics). Diabetics showed a significant increase in blood glucose, cholesterol, triglycerides, LDLc, the ApoB, Lp(a), urea, uric acid, creatinine and cystatin C and lower HDLc. Cystatin was increased in patients with degenerative complications and in hypertensive patients. We found strong correlations of cystatin C with creatinine (r = 0.9454), urea (r = 0.8999) and uric acid (r = 0.8325). We found a significant exponentially increase of creatinine and cystatin C from one stage to another. Cystatin C has a strong association with MDRD (r = 0.8086) and CG (r = 0.7915) and a low one with creatinine clearance (r = 0.1044). In conclusion, the use of cystatin C for screening and early treatment of incipient diabetic nephropathy appears to be adequate. CG and MDRD formulas still hold their place, in regards to the classical determination of creatinine clearance, to monitor patients.     

Performances of single tube nested polymerase chain reaction and GeneXpert ultra on Formalin fixed paraffin embedded tissues in the diagnosis of tuberculous spondylodiscitis

Clinical Rheumatology - Tuberculous Spondylodiscitis is the most common form of musculoskeletal tuberculosis. Molecular techniques on fresh tissues are proved to improve the diagnosis of...     

Macrozoospermia: screening for the homozygous c.144delC mutation in AURKC gene in infertile men and estimation of its heterozygosity frequency in the Tunisian population

Purpose

Macrozoospermia is a rare condition of male infertility characterized by the presence of close to 100 % large-headed multiflagellar spermatozoa. The homozygous mutation (c.144delC) in aurora kinase C gene (AURKC) has been identified as the most frequent mutation causing macrozoospermia in North African patients. The aim of this study was to evaluate the prevalence of this condition in Tunisia and estimate the frequency of c.144delC mutation among infertile and control populations.

Methods

Sequencing c.144delC mutation was carried out in 33 macrozoospermic patients among 6652 infertile men. Minisequencing of exon3 was performed in 250 unrelated control individuals to estimate the frequency of c.144delC heterozygosity.

Results

More than 80 % of macrozoospermic patients were c.144delC homozygous. The prevalence of homozygous c.144delC was 0.4 % among infertile men (27/6652). The frequency of heterozygosity was 0.4 % among controls (1/250). Surprisingly, it is five times less common than established in the general population of North Africa (2 %) or in the Moroccan population (1.7 %).

Conclusions

We show that this mutation is relatively less frequent in the Tunisian population than in other Maghrebian populations. The occurrence of homozygous mutation among infertile men can be attributed to the high rate of consanguinity and its impact on the expression of this autosomal recessive male infertility disorder rather than a high frequency of heterozygous carriers among the general population. This highlights the importance of the molecular analysis of AURKC mutations for infertile men with high percentage of large-headed multiflagellar spermatozoa in order to limit unnecessary in vitro fertilization attempts for them.     

Phytochemical,antioxidant and protective effect of cactus cladodes extract against lithium-induced liver injury in rats

Context: Opuntia ficus-indica (L.) Mill. (Castaceae) (cactus) is used in Tunisian medicine for the treatment of various diseases.

Objective: This study determines phytochemical composition of cactus cladode extract (CCE). It also investigates antioxidant activity and hepatoprotective potential of CCE against lithium carbonate (Li₂CO₃)-induced liver injury in rats.

Materials and methods: Twenty-four Wistar male rats were divided into four groups of six each: a control group given distilled water (0.5?mL/100?g b.w.; i.p.), a group injected with Li₂CO₃ (25?mg/kg b.w.; i.p.; corresponding to 30% of the LD₅₀) twice daily for 30 days, a group receiving only CCE at 100?mg/kg of b.w. for 60 days and then injected with distilled water during the last 30 days of CCE treatment, and a group receiving CCE and then injected with Li₂CO₃ during the last 30 days of CCE treatment. The bioactive components containing the CCE were identified using chemical assays.

Results: Treatment with Li₂CO₃ caused a significant change of some haematological parameters including red blood cells (RBC), white blood cells (WBC), haemoglobin content (Hb), haematocrit (Ht) and mean corpuscular volume (VCM) compared to the control group. Moreover, significant increases in the levels of glucose, cholesterol, triglycerides and of aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP) and lactate dehydrogenase (LDH) activities were observed in the blood of Li₂CO₃-treated rats. Furthermore, exposure to Li₂CO₃ significantly increased the LPO level and decreased superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) activities in the hepatic tissues.

Conclusion: CCE possesses a significant hepatoprotective effect.     

Molecular mechanisms of tetracycline and macrolide resistance and emm characterization of Streptococcus pyogenes isolates in Tunisia

Streptococcus pyogenes or group A Streptococcus, a major human pathogen, remains susceptible to beta-lactams, but resistance to other antibiotics is becoming more common. The purpose of this study was to characterize both phenotypic and genotypic epidemiological markers of group A Streptococcus and to identify the mechanisms of resistance to macrolides and tetracyclines. A total of 103 strains, isolated at Charles Nicolle University Hospital of Tunis, were investigated. The rate of resistance to erythromycin was low (5%), whereas a high rate of tetracycline resistance was found (70%). All the macrolide-resistant isolates expressed the constitutive macrolide, lincosamide, and streptograminB phenotype and harbored the erm(B) gene. Resistance to tetracycline was mainly due to the tet(M) gene, which is commonly associated with the conjugative transposon Tn916. No significant association was found between erm(B) and tet(M) genes. The tetracycline-resistant strains belonged to 28 distinct emm types. Among them, emm118 was the most prevalent type, followed by emm42, std432, emm76, and emm18. However, emm1, emm4, emm6, emm28, and emm3 were the most frequent types among tetracycline susceptible isolates. Only emm118 and emm42 types (p ≤ 0.05) were significantly associated with resistance to tetracycline.     

Measures of anxiety, amygdala volumes, and hippocampal scopolamine phMRI response in elderly female rhesus macaques

In nonhuman primates, anxiety levels are typically assessed by observing social hierarchies or behavior in an intruder task. As measures of anxiety might influence performance on a particular cognitive task, it is important to analyze these measures in the same room as used for the cognitive task. As we use a playroom for the spatial maze test, we classified elderly female rhesus macaques (Macaca mulatta) monkeys, as bold or reserved monkeys based on the time spent in specific areas of this room. Based on their exploratory behavior in the playroom, bold monkeys were defined as animals that spent 20% more time in the unprotected areas of the room than in the protected areas, whereas reserved monkeys spent a comparable amount of time in both areas. MRI analyses showed that reserved monkeys had a smaller amygdala compared to bold monkeys but there were no group differences in hippocampal volumes. In addition, the amount of time spent in the corners of the room was negatively correlated with the right amygdala as well as the total amygdala size. Finally, reserved monkeys showed a lower phMRI response to the muscarinic receptor antagonist scopolamine compared to the bold monkeys. Thus, in elderly female nonhuman primates measures of anxiety are associated with structural amygdala differences and hippocampal muscarinic receptor function. This article is part of a Special Issue entitled 'Anxiety and Depression'.     

N-acetylcysteine improves redox status, mitochondrial dysfunction, mucin-depleted crypts and epithelial hyperplasia in dextran sulfate sodium-induced oxidative colitis in mice

The effect of N-acetylcysteine (NAC), a pharmacological antioxidant was investigated in a murine model of chronic colitis. Male NMRI mice were given 5% dextran sulfate sodium (DSS) in drinking water for 5 days followed by 10 days of water, three times. Compared to control mice given water, DSS-treated mice displayed severe imbalanced redox status with decreased glutathione and catalase, but increased malondialdehyde, protein carbonyls, nitric oxide and myeloperoxidase levels, at days 35th (active colitis) and 45th (recovery period). It also resulted in mitochondrial dysfunction, mucosal ulcers, mucin-depleted crypts and epithelial cell apoptosis. Crypt abscesses and glandular hyperplasia occurred selectively in distal colon. NAC (150mg/kg) given in drinking water for 45 days along with 3 DSS cycles improved the hallmarks of DSS-colitis. Interestingly, the moderate impact of NAC on lipids and proteins oxidation correlated with myeloperoxidase and nitric oxide levels.NAC as a mucoregulator and a thiol restoring agent is protective on oxidative crypt alterations, mucin depletion, epithelial cell hyperplasia and apoptosis. Taken together, our results highlight the role of NAC as a scavenger of phagocytes-derived reactive oxygen species in mice DDS-colitis, suggesting that a long term NAC diet might be beneficial in inflammatory bowel diseases and colorectal cancer.     

Immune senescence in aged nonhuman primates

Aging is accompanied by a general dysregulation in immune system function, commonly referred to as ‘immune senescence’. This progressive deterioration affects both innate and adaptive immunity, although accumulating evidence indicates that the adaptive arm of the immune system may exhibit more profound changes. Most of our current understanding of immune senescence stems from clinical and rodent studies. More recently, the use of nonhuman primates (NHPs) to investigate immune senescence and test interventions aimed at delaying/reversing age-related changes in immune function has dramatically increased. These studies have been greatly facilitated by several key advances in our understanding of the immune system of old world monkeys, specifically the rhesus macaques. In this review we describe the hallmarks of immune senescence in this species and compare them to those described in humans. We also discuss the impact of immune senescence on the response to vaccination and the efficacy of immuno-restorative interventions investigated in this model system.