Bidirectional Synthesis of 6-Acetoxy-5-hexadecanolide, the Mosquito Oviposition Pheromone of Culex quinquefasciatus, from a C2-Symmetric Building Block Using Olefin Metathesis Reactions.

(5R,6S)-6-Acetoxy-5-hexadecanolide (MOP) is the oviposition pheromone of the mosquito Cx. quinquefasciatus, a vector of pathogens causing a variety of tropical diseases. We describe and evaluate herein three syntheses of MOP starting from mannitol-derived (3R,4R)-hexa-1,5-diene-3,4-diol. This C2-symmetric building block is elaborated through bidirectional olefin metathesis reactions into 6-epi-MOP, which was converted into MOP via Mitsunobu inversion. The shortest of the three routes makes use of two sequential cross-metathesis reactions and an assisted tandem catalytic olefin reduction, induced by an in situ conversion of a Ru-carbene to a Ru-hydride.

Total syntheses of naturally occurring seimatopolide A and its enantiomer from chiral pool starting materials using a bidirectional strategy.

Enantioselective total syntheses of both enantiomers of the recently isolated decanolide natural product seimatopolide A are described. The C(2)-symmetric building blocks (R,R)-hexa-1,5-diene-3,4-diol (derived from D-mannitol) and its enantiomer (derived from l-(+)-tartrate) serve as key starting materials, which are elaborated in a bidirectional way using a selective mono-cross-metathesis, regio- and stereoselective epoxidation, and regioselective reductive epoxide opening to furnish the first fragment. Both enantiomers of the second fragment, 3-hydroxypent-4-enoic acid, were conveniently obtained through a lipase-catalyzed kinetic resolution and merged with the first fragment via Shiina esterification. An E-selective ring-closing metathesis was used to access the 10-membered lactone. A comparison of the specific optical rotations of synthetic seimatopolides with those reported for the natural product suggests that the originally assigned (3R,6R,7R,9S)-configuration should be corrected to (3S,6S,7S,9R).

[Lumbosciatica caused by spondylolisthesis. Results of the surgical treatment by facetolaminectomy and interbody arthrodesis by the posterior approach in a series of 66 cases]. / Lombo-sciatique par spondylolisthésis. Résultats du traitement chirurgical par facetto-laminectomie et arthrodèse inter-somatique par voie postérieure dans une série de 66 cas opérés.

66 patients with spondylolisthesis were reviewed after surgical procedure with a follow-up period of more than a year postoperatively. The indication for the operation was disabling sciatica in all patients. 4 patients had undergone prior excision of the herniated disc. All the patients underwent a removal of the loose posterior element as suggested by the Gill procedure and intervertebral body fusion using a posterior surgical approach. The surgical procedures with only one regressive neurological complication are described. The results are considered from a clinical and anatomo-radiological point of view. In this series 86.5 percent of 66 patients became sciatica-free. 62 percent of the total series rated the end result as excellent or good. 92.4 percent of the patients demonstrated bony fusion between the two grafted vertebrae. The benefits of posterior laminectomy with interbody fusion are also attractive for spondylolisthesis with sciatica.

Histological study of necrolytic acral erythema.

Described in 1996, necrolytic acral erythema remains the sole diagnostic cutaneous marker for hepatitis C virus infection. To date only eight cases have been described in literature, a fact that makes full histological description and appreciation of the disease process inadequate. Thirty necrolytic acral erythema cases were biopsied and detailed histological description was performed by three separate dermatopathologists who were blinded as to clinical presentation. Clinicopathological correlation was used to evaluate the disease progress. In the early stage, there is moderate regular acanthosis with variable spongiosis and inflammation, progressing to a picture resembling nummular eczema. In its fully evolved form, necrolytic acral erythema shows psoriasiform epidermal hyperplasia with marked papillomatosis. Associated findings include parakeratosis, focal hypergranulosis, subcorneal pustule, epidermal pallor, necrotic keratinocytes, which sometimes become confluent in the upper epidermis and/or track along the acrosyringia, vascular ectasia and papillary dermal inflammation. Late stage samples display some remaining acanthosis with variable inflammation. Pigment incontinence is seen in all stages.