The crystal structures of 3-O-benzyl-1,2-O-iso-propyl-idene-5-O-methane-sulfonyl-6-O-tri-phenyl-methyl-α-d-gluco-furan-ose and its azide displacement product.

The effect of different leaving groups on the substitution versus elimination outcomes with C-5 d-glucose derivatives was investigated. The stereochemical configurations of 3-O-benzyl-1,2-O-iso-propyl-idene-5-O-methane-sulfonyl-6-O-tri-phenyl-methyl-α-d-gluco-furan-ose, C36H38O8S (3) [systematic name: 1-[(3aR,5R,6S,6aR)-6-benz-yloxy-2,2-di-methyl-tetra-hydro-furo[2,3-d][1,3]dioxol-5-yl)-2-(trit-yloxy)ethyl methane-sulfonate], a stable inter-mediate, and 5-azido-3-O-benzyl-5-de-oxy-1,2-O-iso-propyl-idene-6-O-tri-phenyl-methyl-ß-l-ido-furan-ose, C35H35N3O5 (4) [systematic name: (3aR,5S,6S,6aR)-5-[1-azido-2-(trit-yloxy)eth-yl]-6-benz-yloxy-2,2-di-methyl-tetra-hydro-furo[2,3-d][1,3]dioxole], a substitution product, were examined and the inversion of configuration for the azido group on C-5 in 4 was confirmed. The absolute structures of the mol-ecules in the crystals of both compounds were confirmed by resonant scattering. In the crystal of 3, neighbouring mol-ecules are linked by C-H⋯O hydrogen bonds, forming chains along the b-axis direction. The chains are linked by C-H⋯π inter-actions, forming layers parallel to the ab plane. In the crystal of 4, mol-ecules are also linked by C-H⋯O hydrogen bonds, forming this time helices along the a-axis direction. The helices are linked by a number of C-H⋯π inter-actions, forming a supra-molecular framework.

Back to (non-)Basics: An Update on Neutral and Charge-Balanced Glycosidase Inhibitors.

Glycosidases have important anti-cancer, anti-viral and anti-diabetic properties. This review covers the literature in the past 15 years since our initial review in this journal on "neutral" glycosidase inhibitors lacking a basic nitrogen found in iminosugars and azasugars or inhibitors that are neutral by virtue of being "charge-balanced" (zwitterionic). These structurally diverse inhibitors include lactones, lactams, epoxides such as cyclophellitol, and sulfonium ion derivatives of the natural product salacinol. Synthetic efforts toward cyclophillitol, salicinol and derivatives are also highlighted. Importantly, certain metals can inhibit glycosidases and care must be taken to remove residual catalysts from synthetic material to be tested against these enzymes.

Identification of electric-field-dependent steps in the Na(+),K(+)-pump cycle.

The charge-transporting activity of the Na(+),K(+)-ATPase depends on its surrounding electric field. To isolate which steps of the enzyme's reaction cycle involve charge movement, we have investigated the response of the voltage-sensitive fluorescent probe RH421 to interaction of the protein with BTEA (benzyltriethylammonium), which binds from the extracellular medium to the Na(+),K(+)-ATPase's transport sites in competition with Na(+) and K(+), but is not occluded within the protein. We find that only the occludable ions Na(+), K(+), Rb(+), and Cs(+) cause a drop in RH421 fluorescence. We conclude that RH421 detects intramembrane electric field strength changes arising from charge transport associated with conformational changes occluding the transported ions within the protein, not the electric fields of the bound ions themselves. This appears at first to conflict with electrophysiological studies suggesting extracellular Na(+) or K(+) binding in a high field access channel is a major electrogenic reaction of the Na(+),K(+)-ATPase. All results can be explained consistently if ion occlusion involves local deformations in the lipid membrane surrounding the protein occurring simultaneously with conformational changes necessary for ion occlusion. The most likely origin of the RH421 fluorescence response is a change in membrane dipole potential caused by membrane deformation.

The correlation between anterior ischemic optic neuropathy the non-arthritic form, and the treatment involving alpha-interferon.

The anterior ischemic optic neuropathy is an uncommon complication of alpha-Interferon treatment, characterized by the either temporary or permanent diminishing in visual acuity. We are hereby presenting the clinical case of an anterior ischemic optic neuropathy (non-arteritic form) complicating interferon therapy for Chronic Hepatitis C. In such cases we recommend ophthalmological examinations and if severe ophthalmologic complications occur antiviral treatment should be stopped immediately.

Beneficial dexa-related effects of natural polyphenols on experimentally-induced diabetes mellitus complications.

UNLABELLED: The benefits of the proanthocyanidins, polyphenols extracted from black grapes seeds, have been shown by using as experimental model, namely streptozotocin-induced diabetes mellitus on Wistar white rats. MATERIAL AND METHOD: Streptozotocin was administered in a single intraperitoneal dose of 60 mg/Kg body mass. Vegetal polyphenols were administered as water solution, in a dose of 0.028 mg/Kg body mass, p.o. (through tube feeding), every two days, for a period of 16 weeks. We performed DEXA bone mineral density tests, in order to determine BDM (bone mineral density in g/cm2), BMC (body mass index expressed in g) and fat (%Fat) in control and diabetic animals, before and after polyphenol delivery. RESULTS: The evolution of bone mineral density depending on the area, in diabetic males, measured from the beginning to the end of the experiment, has shown a significant decrease, especially in the femur area. In diabetic males that received polyphenol treatment, these differences are statistically minimum. Bone mineral density depending on the area showed the highest differences in the spine, followed by the cervical spine. In diabetic males that received polyphenol treatment, we noticed a 4-7% decrease of their body fat as compared to the beginning of the experiment, for all the analyzed samples. As for the spine, the highest BMC difference depending on the area was found in diabetic males with polyphenol intake, and the overall highest difference was noticed in diabetic males. The body fat index we studied in the male groups was the lowest in the diabetic males. CONCLUSION: Osteoporosis regression due to polyphenols proves the benefits of proanthoyianidins used treating the chronic complications of diabetes mellitus.

[Acute posterior multifocal placoid pigmentary epitheliopathy--case report ]. / Epiteliopatie pigmentara placoida multifocala posterioara acuta--caz clinic.

We present a case of young female diagnosed with acute posterior multifocal placoid pigment epitheliopathy, presented with decreased visual acuity. Main differential diagnosis were discussed as well as some general data regarding the pathology of this relatively rare syndrome.

Evaluación de la reserva materno-fetal de hierro en embarazos a término / Evaluation of the maternal-fetal iron stores in full-term pregnancies

Introducción. Hay controversia acerca del cuales son los valores maternos de hemoglobina (Hb) y ferritina sérica (FS), que resultan críticos para generar cambios en la reserva de hierro fetal documentada al nacimiento. Material y métodos: Se diseñó un estudio prospectivo, descriptivo y transversal, para seleccionar a mujeres embarazadas y sus hijos nacidos a término, analizando sus variables demográficas, índices eritrocitarios y FS. Resultados. Se incluyeron a 41 madres y sus respectivos hijos. La población fue estratificada grupo en 2 grupos; un grupo cuando presentaron valores de FS materna menor o igual a 10 µg/L y el otro grupo cuando la FS fue mayor de 10 µg/L. Con este criterio no se observaron diferencias en las variables maternas de número de gestaciones o partos, ni en los índices eritrocitarios, ni en las variables neonatales (peso, talla o índices eritrocitarios). La única diferencia se presntó en la FS neonatal promedio que fue de 115 µg/L, cuando la madre tuvo valores de FS menor o igual a 10 µg/L y de 172 µg/L, cuando la madre presentó concentraciones de FS superiores a este valor al final del embarazo (P=0.007). Conclusión. Se demuestra el efecto desfavorable sobre la reserva fetal de hierro en hijos de madre con ferropenia extrema, señalándose como un grupo de riesgo de afección fetal