Hemodynamically significant early recurrent carotid stenosis: an often self-limiting and self-reversing condition.

PURPOSE: The natural history of hemodynamically significant (internal carotid systolic velocity more than 125 cm/s) early recurrent carotid stenosis was studied. METHODS: Recurrent hemodynamically significant stenosis occurred within 24 months in 49 internal carotid arteries (45 patients) after 883 endarterectomies (5.4%). These patients were then examined with serial scans. Subsequent redo endarterectomy and neurological events were recorded. RESULTS: Patients were observed for 9 to 84 months (mean, 53 months). Arteries with recurrent stenosis were grouped according to the maximal velocity recorded: group I, systolic velocity more than 125 cm/s and less than 280 cm/s (12); group II, systolic velocity more than 280 cm/s or diastolic velocity more than 80 cm/s (21); group III, systolic velocity more than 280 cm/s and diastolic velocity more than 120 cm/s (14); group IV, internal carotid artery occlusion (2). The mean time to a velocity of more than 125 cm/s was 11 months. The mean time to peak velocity was 16 months. During The Follow-UP Period, Five Stenoses Remained Stable. Nineteen Continued To Increase, With Two Eventual Asymptomatic Occlusions (4%). Six Recurrences Ultimately Had Redo Endarterectomy, Two For Symptoms. Three Of These Developed New Secondary Recurrent Lesions. However, In 25 Arteries (53%), The Velocity Profile Decreased By At Least One Group Classification. The Mean Time To The Lowest Velocity (TTL) Was 50 Months. Systolic Velocity Ultimately Fell Below 125 Cm/S In 13 Stenoses (SIX In Group I; Five In Group II; Two In Group III). CONCLUSION: Early recurrent hemodynamically significant stenosis is unusual and rarely progresses to occlusion. Even critical stenosis can regress to within normal limits. Redo endarterectomy is seldom necessary. The challenge remains to define which patients are at risk for symptoms and occlusion.

Ethyl (Z)-9-hexadecenoate a sex pheromone ofSyndipnus rubiginosus, a sawfly parasitoid.

A female-produced sex pheromone ofSyndipnus rubiginosus Walley (Hymenoptera: Ichneumonidae), a parasitoid of the yellowheaded spruce sawfly,Pikonema alaskensis (Rohwer) (Hymenoptera: Tenthredinidae), was isolated and identified from hexane extracts of 250 virgin females. Column chromatography (Florisil), gas chromatography, mass spectrometry, high performance liquid chromatography, and ozonolysis indicated the structure was ethyl (Z)-9-hexadecenoate. The optimum male response is at 300-1000 ng (3-10FE). No cross-attraction betweenS. rubiginosus and the sympatric sawfly parasitoidS. gaspesianus (Provancher) could be demonstrated.

Evidence for a multicomponent sex pheromone in the yellowheaded spruce sawfly.

The existence of a female-produced sex pheromone in the yellowheaded spruce sawfly,Pikonema alaskensis (Rohwer) (Hymenoptera: Tenthredinidae) was demonstrated by field and greenhouse bioassays. Virgin females, their empty cocoons (with which they were confined during handling procedures), and the hexane extract of these cocoons were attractive in the field. The only Florisil fraction of this extract consistently attractive by itself was that eluted with hexane, but three, more polar fractions (eluted with 5%, 25%, and 50% ether in hexane) each synergized the hexane fraction, increasing bioassay responses 10-30 times. Fractions derived directly from virgin females yielded comparable results. The greenhouse data corroborated the field data, except that the 5% ether-hexane fraction, while very synergistic in the field, was consistently inactive in the greenhouse.

Hydrocarbon components of the yellowheaded spruce sawfly sex pheromone : A series of (Z, Z)-9, 19 dienes.

The primary sex pheromone of the yellowheaded spruce sawfly,Pikonema alaskensis (Rohwer) (Hymenoptera: Tenthredinidae), was found to include a series of straight-chain hydrocarbon dienes, all with the double bonds in the 9 and 19 positions and all with the (Z, Z) configuration. The major components, of 29, 31, 33, 35, and 37 carbon atoms, were synthesized. In the field and the greenhouse, the synthetic dienes were far above control levels in activity but, at least during the first hours of bioassay, were somewhat less active than the female-derived materials on a weight basis. In the field, a mixture of all five synthetic dienes, in the proportions found in the females, was more attractive than any single one, on a mole basis. In addition, (Z, Z)-9,19 dienes of 28, 30, 32, 34, 36, 38, and 39 carbons have been detected in females in minor amounts. The first five were bioassayed, and each was found to be similar in activity to the 35-carbon component when compared on a weight basis. The synthetic dienes, while active by themselves, were strongly synergized by two, more polar, Florisil fractions derived from females. Experimental design considerations are discussed.