Thrombocytosis in rheumatoid arthritis: JAK2V617F-positive essential thrombocythemia

Thrombocytosis is an important laboratory finding in rheumatoid arthritis (RA) and it has a correlation with disease activity. Janus kinase 2 valin 617 phenylalanine (JAK2V617F) mutation has gained importance in the diagnosis of myeloproliferative diseases recently. There is no published report in literature on the association between RA and JAK2V617F-positive essential thrombocythemia (ET). In this report, we present a JAK2V617F-positive ET case that had RA. A 57-year-old male patient was diagnosed with RA according to the criteria of American College of Rheumatology (ACR), whose complaint was of pain in the hands and morning stiffness lasting for about 2 h. The patient was evaluated for thrombocytosis because he was in remission and suffering persistent thrombocytosis under treatment. After excluding the causes of secondary thrombocytosis, bone marrow aspiration and biopsy was performed. On peripheral blood and bone marrow PCR examination, the patient was detected to be JAK2V617F positive heterozygously and diagnosed with ET. As a conclusion, mild–moderate thrombocytosis is frequent in RA; however, ET can be diagnosed by JAK2V617F evaluation in peripheral blood in thrombocytosis, especially when platelet count is more than 1 million/ml and when persisting thrombocytosis is detected in RA remission.     

Tyrosinemia type II: Novel mutations in TAT in a boy with unusual presentation

Tyrosinemia type II is a rare autosomal recessive disorder caused by deficiency of tyrosine aminotransferase (TAT). It may occur with ocular and cutaneous symptoms with or without mental retardation, but epileptic seizure is a rare presentation of this disease. Herein we report the clinical, biochemical and genetic features of a 4‐year‐old boy who presented with afebrile seizure and photophobia. Genomic DNA was obtained from peripheral blood leukocytes from the whole family. Sequencing analysis was performed using the MiSeq next‐generation sequencing platform. Sequencing of TAT indicated two new homozygous mutations p.L312P (c.935T>C) and p.T408M (c.1223C>T) for the proband and his asymptomatic sister. During a 2 year follow‐up period, the patient had overall poor compliance with protein‐restricted diet, but his asymptomatic sister had good compliance with the diet. Cognitive function of the patient worsened steadily, but his asymptomatic sister maintained normal mental status. Tyrosinemia type II should be considered in the differential diagnosis of children presenting with epileptic seizure and photophobia; furthermore, early diagnosis and protein‐restricted regimen are important to reduce the risk of long‐term complications of tyrosinemia type II such as mental disability.     

Effects of sunitinib and bevacizumab on VEGF and miRNA levels on corneal neovascularization

Aim: To evaluate the effects of sunitinib (0.5?mg/ml) and bevacizumab (5?mg/ml) on VEGF-A, VEGFR-2 and microRNA (miRNA) levels on corneal neovascularization (CNV).

Methods: In this study, CNV was induced by silver nitrate application to the cornea, and 40 Albino male rats were equally divided into four subgroups:

Group 1 (sunitinib): After silver nitrate application to the cornea, 0.5?mg/ml sunitinib eyedrop was administered twice daily for two weeks (n?=?10).

Group 2 (bevacizumab): After silver nitrate application to the cornea, 5?mg/ml bevacizumab eyedrop was administered twice daily for two weeks (n?=?10).

Group 3 (control): After silver nitrate application to the cornea, normal saline eyedrop was administered twice daily for two weeks (n?=?10).

Group 4 (vehicle): After silver nitrate application to the cornea, 1% DMSO eyedrop was administered twice daily for two weeks (n?=?10).

After two weeks from the silver nitrate application, corneas were evaluated by hand-held biomicroscope for their vascularization status. Then, corneas were excised and the expression levels of VEGFR-2, VEGF-A and the common miRNA markers for neovascularization (miR-15?b, miR-16, miR-23a, miR-126, miR-188, miR-210, miR-221, miR-222, miR-410 and miR-423) were evaluated by real-time PCR.

Results: It was seen that the CNV was decreased in sunitinib- and bevacizumab-administered groups compared to the control and DMSO groups. Also, in comparison with the control group; VEGF-A expression was downregulated by nearly 0.75 times in sunitinib group and nearly 0.52 times in bevacizumab group. VEGFR-2 expression was downregulated by 0.89 times in sunitinib group and 0.68 times in bevacizumab group, compared to the control group. miR-15?b, miR-16 and miR-126 levels were statistically lower in sunitinib and bevacizumab groups, but miR-188 and miR-410 levels were two-fold higher compared to the control group. The miR-210 level was found higher only in sunitinib group compared to the control group. There were no statistically significant changes in miR-23a, miR-221, miR-222 and miR-423 levels among the groups.

Conclusion: Topical application of bevacizumab (5?mg/ml) and sunitinib (0.5?mg/ml) decreases the levels of VEGFR-2 and VEGF-A in CNV. Further studies are needed for detailed analysis of genes which are targeted by up- or downregulated miRNAs in this study.     

Active site topology and reaction mechanism of GTP cyclohydrolase I.

GTP cyclohydrolase I of Escherichia coli is a torus-shaped homodecamer with D5 symmetry and catalyzes a complex ring expansion reaction conducive to the formation of dihydroneopterin triphosphate from GTP. The x-ray structure of a complex of the enzyme with the substrate analog, dGTP, bound at the active site was determined at a resolution of 3 A. In the decamer, 10 equivalent active sites are present, each of which contains a 10-A deep pocket formed by surface areas of 3 adjacent subunits. The substrate forms a complex hydrogen bond network with the protein. Active site residues were modified by site-directed mutagenesis, and enzyme activities of the mutant proteins were measured. On this basis, a mechanism of the enzyme-catalyzed reaction is proposed. Cleavage of the imidazole ring is initiated by protonation of N7 by His-179 followed by the attack of water at C8 of the purine system. Cystine Cys-110 Cys-181 may be involved in this reaction step. Opening of the imidazole ring may be in concert with cleavage of the furanose ring to generate a Schiff's base from the glycoside. The gamma-phosphate of GTP may be involved in the subsequent Amadori rearrangement of the carbohydrate side chain by activating the hydroxyl group of Ser-135.     

La santé des pasteurs mobiles au Sahel – Bilan de 15 années de recherches et développement

Dans le Sahel, entre la Mauritanie et la Somalie incluant le Nord Kenya, environ 20 à 30 millions de personnes vivent en transhumance. Le rythme de leur migration suit l’évolution saisonnière du climat et la disponibilité des ressources, telle que l'eau, le pâturage et le sel. Malgré une exposition élevée à certaines maladies comme les zoonoses et les problèmes conditionnés liés au climat, les pasteurs mobiles sont parmi les populations quasiment exclues du système de santé, car la mise à disposition des services sociaux adaptés à un mode de vie mobile est difficile. Suivant l'objectif de recherche d'un meilleur accès aux soins des pasteurs mobiles, l'Institut Tropical et de Santé Publique Suisse, en partenariat avec plusieurs institutions dans la région, est actif au Sahel depuis 15 ans, aussi bien dans le domaine de la recherche, que celui des actions de développement. Basées sur une approche orientée vers les besoins des pasteurs mobiles pour leur développement, des recherches interdisciplinaires ont contribué à mieux comprendre la situation et les problèmes des éleveurs. En relation de la proximité entre l'homme et son bétail, une approche unissant la santé humaine et animale s'est avérée bonne et la valeur ajoutée d'une meilleure collaboration entre médecine humaine, animale et l'environnement a été démontrée. Ces approches utiles devraient être poursuivies et consolidées dans les recherches et le développement des actions futurs.     

Nucleolar organizer regions in lymphomas

Using a silver staining technique, nucleolar organizer region-associated proteins (Ag-NORs) have been studied in paraffin sections of 90 non-Hodgkin's lymphomas, five palatine tonsils and five 'reactive' lymph nodes. The method was readily applicable to these preparations and the Ag-NORs were enumerated with ease. A significant difference was found between the numbers of Ag-NORs in the nuclei of low-grade lymphomas (from a mean of 1 to 1.5 per nucleus) and those of high-grade lymphomas (a mean of 4.4 to 6.8 per nucleus). The Ag-NOR regions were often observed in nuclei in areas where nucleoli themselves were not visible. It is suggested that this method, previously largely the province of the cytogeneticist, should find widespread applications in the field of tumour histopathology.     

Rotational stability of Seidel nail distal locking mechanism

The intramedullary distal locking mechanism in the Seidel nail uses interference fit, avoiding the need of a screw traversing soft tissue and the risk of neurovascular injury. However, there is concern for its rotational stability. This study was designed to test the rotational stability of the distal locking mechanism under the least stable conditions. A transverse osteotomy was performed 10 cm proximal to the trochlea in 10 cadaveric humeri, followed by insertion of a 9 mm diameter Seidel nail and distally locked. The proximal humeral segments were removed. Rotational test to failure was performed with a material testing machine. The initial medullary diameter and the amount of flange spread measured 9.95 mm and 11.28 mm, respectively. Most of the flanges were found to be incompletely deployed. Failure occurred by slippage of the flanges. The average failure torque and torsional stiffness of the nail bone construct tested were 0.262 N m and 0.070 N m/ degrees . The Seidel nail distal locking mechanism has low rotational stability on mechanical testing. However, the low failure torque tested in vitro does not always preclude successful fracture healing and a good clinical outcome. Whether the presence of rotational micro motion would be beneficial to bone healing would need further investigation.