Circulation and Molecular Epidemiology of Enteroviruses in Paralyzed,Immunodeficient and Healthy Individuals in Tunisia,a Country with a Polio-Free Status for Decades

This report is an overview of enterovirus (EV) detection in Tunisian polio-suspected paralytic cases (acute flaccid paralysis (AFP) cases), healthy contacts and patients with primary immunodeficiencies (PID) during an 11-year period. A total of 2735 clinical samples were analyzed for EV isolation and type identification, according to the recommended protocols of the World Health Organization. Three poliovirus (PV) serotypes and 28 different nonpolio enteroviruses (NPEVs) were detected. The NPEV detection rate was 4.3%, 2.8% and 12.4% in AFP cases, healthy contacts and PID patients, respectively. The predominant species was EV-B, and the circulation of viruses from species EV-A was noted since 2011. All PVs detected were of Sabin origin. The PV detection rate was higher in PID patients compared to AFP cases and contacts (6.8%, 1.5% and 1.3% respectively). PV2 was not detected since 2015. Using nucleotide sequencing of the entire VP1 region, 61 strains were characterized as Sabin-like. Among them, six strains of types 1 and 3 PV were identified as pre-vaccine-derived polioviruses (VDPVs). Five type 2 PV, four strains belonging to type 1 PV and two strains belonging to type 3 PV, were classified as iVDPVs. The data presented provide a comprehensive picture of EVs circulating in Tunisia over an 11-year period, reveal changes in their epidemiology as compared to previous studies and highlight the need to set up a warning system to avoid unnoticed PVs.     

Notch-1 activation and dendritic atrophy in prion disease

In addition to neuronal vacuolation and astrocytic hypertrophy, dendritic atrophy is a prominent feature of prion disease. Because increased Notch-1 expression and cleavage releasing its intracellular domain (NICD) inhibit both dendrite growth and maturation, we measured their levels in brains from mice inoculated with Rocky Mountain Laboratory (RML) prions. The level of NICD was elevated in the neocortex, whereas the level of beta-catenin, which stimulates dendritic growth, was unchanged. During the incubation period, levels of the disease-causing prion protein isoform, PrPSc, and NICD increased concomitantly in the neocortex. Additionally, increased levels of Notch-1 mRNA and translocation of NICD to the nucleus correlated well with regressive dendritic changes. In scrapie-infected neuroblastoma (ScN2a) cells, the level of NICD was elevated compared with uninfected control (N2a) cells. Long neurofilament protein-containing processes extended from the surface of N2a cells, whereas ScN2a cells had substantially shorter processes. Transfection of ScN2a cells with a Notch-1 small interfering RNA decreased Notch-1 mRNA levels, diminished NICD concentrations, and rescued the long process phenotype. These results suggest that PrPSc in neurons and in ScN2a cells activates Notch-1 cleavage, resulting in atrophy of dendrites in the CNS and shrinkage of processes on the surface of cultured cells. Whether diminishing Notch-1 activation in vivo can prevent or even reverse neurodegeneration in prion disease remains to be established.     

Intestinal T cell lymphoma in coeliac disease. A case report

Primary intestinal T-cell lymphomas account for about 5% of all primary gastrointestinal lymphomas and are mostly associated with coeliac disease. Intestinal lymphomas are usually discovered during the 4th to 5th decade and constitute an exceptional complication of coeliac disease. This lymphoma is generally a high grade pleomorphic cell lymphoma with large cells. Our case concerned a 30 year old woman with a history of coeliac disease who developed a gastro-enteromesenteric lymphoma. Anatomopathological and immunohistochemical analysis showed an enteropathy associated T-cell lymphoma. We suggest that patients with coeliac disease unresponsive to a gluten free diet or with deteriorating clinical condition be investigated for complications such as enteropathy associated T-cell lymphoma. It is also important to avoid this complication by detecting asymptomatic form of coeliac disease that needs a gluten-free diet.     

The neurodegeneration sequence in prion diseases: evidence from functional, morphological and ultrastructural studies of the GABAergic system

Loss of the GABAergic system of neurons has been reported to be the first detectable neuropathological change in prion diseases, which features the accumulation of an aberrant isoform of the prion protein (PrP(Sc)). To determine the timing of GABAergic system dysfunction and degeneration and its relationship to PrP(Sc) accumulation during the course of prion disease in Syrian hamsters, we applied 3 approaches: i) quantifying GABA-immunopositive neurons and their processes by light and electron microscopy to test for selective loss; ii) measuring evoked [3H]-GABA release from synaptosomes to test for functional abnormalities; and iii) determining the kinetics of PrP(Sc) accumulation in subcellular fractions to correlate it with GABAergic dysfunction. At the terminal stages of disease, we found a significant increase in the number of GABA-positive and -negative presynaptic boutons with abnormally aggregated synaptic vesicles. At the same stage, we also found an equal degree of GABA-immunopositive and -immunonegative presynaptic bouton loss. In contrast, GABA-positive neocortical cell bodies increased, based on stereologic estimates in the terminal stage of scrapie. In the context of these abnormalities, evoked release of [3H]-GABA from cortical and thalamic synaptosomes was significantly decreased, which correlated well with the accumulation of PrP(Sc) in synaptosomes and cell membrane fractions.     

Extruded and protruded lumbar discs: combined clinical, histopathological, histochemical, immunopathological, histochemical, immunopathological and ultrastructural studies.

A total number of selected 252 patients with prolapsed lumbar intervertebral discs (92 extruded and 160 protruded) were operated upon in Neurosurgery Department Zagazig University Hospital during the period extended from January, 1988, to October 1990. In this study we reviewed their clinical and operative data. Surgical biopsies were taken from randomly selected 120 patients of them (50 extruded and 70 protruded discs) and were subjected to histopathological, histochemical and immunopathological studies. Ultrastructural study was performed for randomly selected 14 cases (7 extruded and 7 protruded discs). The results were compared with 7 normal intervertebral discs obtained from these studies showed that there were no differences between extruded and protruded discs at the histochemical level. Cell mediated immunity could be added as a factor in the pathogenesis of the degenerative process that lead to disc prolapse (in 20% of cases with extruded discs and 57.1% of cases with protruded discs). At the ultrastructural level 85.3% of extruded discs were prolapsed nucleus pulposus while 14.7% were prolapsed annulus fibrosus alone or with nucleus pulposus. All protruded discs were prolapsed annulus fibrosus with nucleus pulposus. These findings may have an impact on the management of this common problem.     

Pulmonary inflammatory pseudotumor: difficulties in diagnosis and prognosis

Inflammatory pseudotumors are uncommon benign lesions of the lung of unknown origin, that may show aggressive behavior. Although pseudotumors constitute less than 1% of all lung tumors, they are reported to be the most common cause of solitary lung masses in children. Complete resection, when possible, is safe and leads to excellent survival. The case presented here highlights difficulties in clinical and histologic diagnosis.     

Takayasu arteritis with coronary aneurysms causing acute myocardial infarction in a young man

Takayasu arteritis is an inflammatory condition that involves the large cardiac vessels, predominantly the aorta and its main branches. It typically affects young women (age, ≤40 yr), most often Asians and Latin Americans. Herein, we describe a rare manifestation of Takayasu arteritis in a 19-year-old black Tunisian man who presented with acute inferior myocardial infarction and complete atrioventricular block after occlusion from a giant aneurysm in the right coronary artery. The coronary artery disease was associated with aneurysmal dilations in the carotid, vertebral, and right renal arteries. Medical therapy improved Thrombolysis in Myocardial Infarction flow in the area of the giant aneurysm from grade 1 to grade 3. Upon the diagnosis of Takayasu arteritis, intravenous methylprednisolone and oral prednisone therapy was started. After 10 days of hospitalization, the patient was discharged on a medical regimen. Renovascular hypertension due to renal artery stenosis was suspected, so he underwent successful percutaneous transluminal angioplasty of the inferior segmental artery of the right renal artery. During 12 months of close postprocedural monitoring, he experienced lower blood pressure, no chest pain, and no cardiovascular complications.This association of conditions has not been previously reported. Besides presenting this very rare combination of findings, we discuss the differential diagnosis of Takayasu arteritis in our patient.