Sites of production and occurrence of volatiles in Douglas-fir beetle,Dendroctonus pseudotsugae hopkins.

Volatiles were found to be distributed throughout adult Douglasfir beetles,Dendroctonus pseudotsugae Hopkins, suggesting that the hindgut may not be the sole site of production. The volatile content of individual beetles increased dramatically with feeding; qualitative changes reflected the different bark habitats of newly emerged and established beetles. All detected volatiles were also found in beetle frass. Myrcene was the predominant monoterpene of emergent beetles and α-pinene of fed beetles. Linalool and bornyl acetate occurred in significant amounts after feeding, and diacetone alcohol and sulcatol were also detected for the first time. The presence of sulcatol explains the reported cross-attraction withGnathotrichus spp.cis-Verbenol was also found to occur in addition totrans-verbenol. The volatile content of male beetles was similar to that of females but amounts of individual compounds were less. Acetic acid was found in both emerged and fed beetles and in lesser amounts in frass, suggesting that microbial metabolism could be a potential source of volatile production.

Effect of lumbar sympathectomy on muscle blood flow: distribution of perfusion measured by hydrogen clearance in skeletal muscle.

Measurements of local tissue blood flow using a technique of hydrogen clearance were used to examine the effect of lumbar sympathectomy on skeletal muscle blood flow. Polarographic recordings on 25 hydrogen desaturations were obtained with platinized platinum electrodes. Lumbar sympathectomies were done on five canines leaving the contralateral limb as a control. The hydrogen clearance data were modeled with biexponential curves: the initial rapid component and the second slow component yielded a weighted average perfusion through tissue. Average volumetric blood flow in the control limb was 6.08 +/- 0.45 ml/min/100 g tissue while the sympathectomized limb averaged 9.54 +/- 0.61 ml/min/100 g tissue (p less than 0.005). Average blood flow increases ranged from 33 to 83 percent in the sympathectomized limb over the control limb. This significant increase in muscle blood flow following lumbar sympathectomy, if of prolonged duration, may be cause for re-evaluation of the role of sympathectomy in the management of arteriosclerotic occlusive disease.

Mandibular gland secretions of two parasitoid wasps (Hymenoptera: Ichneumonidae).

Males ofRhyssa persuasoria andMegarhyssa nortoni nortoni exhibit marked aggregation behavior prior to and during the emergence of females from host trees, and this has been linked with the secretion of an odorous liquid from the mandibular glands. The volatile components of these secretions were examined by combined gas chromatography-mass spectrometry. While both species contained 6-methylhept-5-en-2-one,M. nortoni nortoni was characterized by a series of alkyl spiroacetals andR. persuasoria contained 3-hydroxy-3-methylbutan-2-one. The same spiroacetals have previously been isolated from the mandibular glands of other Hymenoptera and have been directly associated with aggregation behavior in some species. The chemical and behavioral aspects of the two species are discussed.

Blue digit syndrome: urgent indication for digital salvage.

The sudden onset of digital ischemia due to microembolization from a proximal source (the blue digit syndrome) requires immediate attention because not only the digit, but also the entire extremity, may be at risk. In our experience, 11 patients with the blue digit syndrome were encountered. Treatment consisted of eradication of the proximal embolic source followed by lumbar sympathectomy in four patients, direct arterial surgery alone in five patients, and lumbar sympathectomy alone in two patients. The addition of lumbar sympathectomy was beneficial as it provides an additional increase in blood flow and tissue perfusion over and above that due to direct arterial surgery alone. Our experience indicates that the benefits of lumbar sympathectomy leads to enhancement of healing of pregangrenous lesions and digital salvage.

Electrocoagulation as a primary curative method in the treatment of carcinoma of the rectum.

Electrocoagulation as a primary curative method for the treatment of carcinoma of the rectum is of proved merit. The continuation of abdominoperineal resection as the acceptable standard routine for treatment will deny many patients the choice of a proved alternative curative procedure with less risk, a better survival rate and a better quality of life. To confirm or negate the reported efficacy of electrocoagulation in the treatment of carcinoma of the rectum, the initiation of universal prospective studies in its use is warranted.

Lumbar sympathectomy for toe gangrene. Long-term follow-up.

We carried out a retrospective review of 45 patients (50 limbs) with toe gangrene not amenable to direct arterial surgery, and thus managed by lumbar sympathectomy alone. Follow-up data regarding toe salvage, limb salvage, and limb loss were compiled. At 5 and 8 year follow-up cumulative limb salvage was 71 percent and cumulative toe salvage was 51 percent. The presence of diabetes did not significantly influence limb or toe salvage. Mortality during the immediate postoperative period was 2 percent. In the majority of patients with digital gangrene who are not amenable to arterial surgery, lumbar sympathectomy is of benefit for salvaging the limb and the toes.

Effect of suture technique on blood velocity waveforms in the microvascular anastomosis of autogenous vein graft.

In using autogenous vein grafts in microvascular surgery, maintenance of compliance at the site of anastomosis is of importance in achieving patency. Using high-frequency, 20 MHz, pulsed Doppler ultrasonography to monitor blood flow velocity through the vein graft, we have evaluated the effects of continuous and interrupted suture technique on anastomotic compliance in vessels less than 1.5 mm in diameter. In 15 dogs, 15 procedures of each technique, using the continuous technique in one limb and the interrupted technique on the contralateral limb, patency rates for both techniques, documented by arteriography, are 100% at a mean follow-up of 11 weeks. There were no significant differences in the blood velocity profile and pulsatility proximally, distally, and at the graft site between continuous and interrupted technique. This study confirms the suggestion that autogenous vein graft has sufficient elasticity to maintain normal arterial blood velocity waveforms.

Intraoperative anticoagulation during arterial reconstructive procedures.

The technique of thromboelastography was used to monitor the intraoperative administration of heparin during vascular surgical procedures. Interpatient response to 70 units per kilogram of heparin varied widely. There was no need, in any patient, for the use of protamine to reverse the effect of heparin. This, coupled with the absence of hemorrhagic complications, indicates that thromboelastography is a useful method for monitoring the administration of heparin during vascular surgical procedures.

Comparison of continuous and interrupted suture techniques in microvascular anastomosis.

A comparison of the continuous and the interrupted suture techniques, ten procedures each, was performed upon dogs using high frequency pulsed Doppler ultrasonography to monitor blood velocity. No statistically significant differences in the blood velocity profile were found between the two techniques. The pulsatility of the vessels after anastomosis was similar for both techniques. At follow-up examination, mean being 13 weeks, the patency rate was 100 per cent as demonstrated arteriographically for both the continuous and the interrupted techniques with statistically no significant difference in the blood velocity profile. The speed and the ease of completing a continuous anastomosis and its lack of significant hemodynamic differences compared with the interrupted technique speak well for the preferential use of the continuous suture technique.

Technique of venous impedance plethysmography for quantification of venous reflux.

A study was conducted applying a technique of venous impedance plethysmography for the quantitation of venous reflux to a group of 20 normal persons and five patients with postphlebitic limbs. Results demonstrate a significantly higher reflux refilling rate for those patients with postphlebitic limbs compared with the refilling rate for those in the normal group. It is believed that this technique is a valuable diagnostic tool for detecting venous reflux caused by valve incompetence and that it provides an indication of progression of venous insufficiency in the patient.

Use of noninvasive electromagnetic flowmetry in the assessment of peripheral arterial disease.

The need for noninvasive techniques capable of quantitating peripheral arterial insufficiency is becoming increasingly obvious. We have shown the technique of noninvasive elctromagnetic flowmetry to be capable of distinguishing three relatively discrete clinical zones by quantitating the peak pulsatile flow of blood through the thigh and calf. The obtained peak pulsatile flow values were in close agreement with ischemic index values previously reported as grading the degree of ischemia in a patient. In certain patients, the noninvasive electromagnetic flowmeter has yielded information not readily available from Doppler systolic pressure measurements. With the noninvasive technique of electromagnetic flowmetry and Doppler ultrasound, it is possible to confirm and quantitate patient complaints, follow disease progression and document improvement following arterial reconstructive operations. The noninvasive electromagnetic flowmeter has also been shown to be invaluable in the selection of the operative procedure by providing information about arterial run-on, run-in and run-off.

Noninvasive hemodynamic evaluation in selection of amputation level.

Various noninvasive techniques of hemodynamic evaluation have been used to determine the optimal level of amputation. Noninvasively obtained measurements of pressure and blood flow in the lower extremity have been found to be reliable in predicting the probable healing of an amputation. In patients with severely calcified noncompressible arteries, noninvasive electromagnetic flowmeter measurements of peak pulsatile flow provide a more accurate indication of the vascular status of the patient than do blood pressure measurements which, in such patients, frequently exceed 300 millimeters of mercury. Skin thermistor thermometry does not appear to be applicable in patients with extensive severe ischemia of the leg. The need for a reliable method of determining the lowest possible level of amputation is well recognized. Such factors as wound edge bleeding and clinical judgment too often lead to above the knee amputation when, frequently, a more distal amputation could have been possible. Our experience has shown that noninvasive techniques for hemodynamic evaluation are a valuable aid to clinical judgment in determining accurately the lowest level for successful limb amputation.

Management of severe ischemia of the foot secondary to occlusive vascular disease.

One hundred patients, 111 limbs, with gangrene of the lower extremity were initially treated with lumbar sympathectomy. Lumbar sympathectomy appears to be most beneficial in the management of gangrene of the toe with a limb salvage rate of 75 per cent. The best results were seen when only one toe, not the big toe, was involved. Limb salvage dropped to 38 per cent for gangrene of the foot, and with gangrene of the leg, lumbar sympathectomy had no affect. The presence of diabetes had no affect on limb salvage for gangrene of the toe but did have an apparent affect on limb salvage for gangrene of the foot. Sympathectomy appeared to aid in stump healing, with 77 per cent of the amputations done not requiring revision to a higher level. Results of our experience appear to indicate that, for patients presenting with gangrene of the toes or forefoot who are not candidates for reconstructive arterial procedures, lumbar sympathectomy as an initial operative procedure should be given serious consideration.

Assessment of the healing potentials of ulcers of the skin by photoplethysmography.

An objective method of assessing the healing potentials of skin ulcers would eliminate the long waiting period necessary for visual evidence of healing or nonhealing to appear. This would permit the continued conservative treatment for healing ulcers and prompt surgical interventions for those ulcers which are nonhealing. In this preliminary study, the cutaneous blood flow immediately around the ulcer site was studied using the photoplethysmograph. Vigorous cutaneous blood flow shown by good pulsatile wave forms on the photoplethysmograph is shown to be indicative of an ongoing healing process in which spontaneous healing of the ulcer can be predicted. Ulcers with nonpulsatile wave forms fail to heal with conservative management. One patient with nonpulsatile wave forms at the ulcer site showed improvement and eventual healing of the ulcer after undergoing a lumbar sympathectomy. Thus, nonpulsatile blood flow shown by poor wave forms on the photoplethysmograph would suggest early surgical intervention. This method may also aid in determining the extent of surgical excision of the ischemic scar tissue surrounding the chronic skin ulcer.