Electrosurgery: A Review

This article presents a review of hemostasis and electrosurgery. The principles of electrosurgery, including the effect on tissue, vessels, and wound healing, are presented, as are the advantages and disadvantages of its use.     

SONOGRAPHIC ESTIMATION OF PLEURAL FLUID VOLUME IN DOGS

The aim of this study was to find an ultrasonographic method to estimate pleural fluid volume in dogs. Nine canine cadavers of mixed breed were studied. Using a transsternal view, linear measurements from the pleural surface of the midline of the sternebra at the center of the heart to the furthest ventrolateral point of both right and left lung edges were recorded. Isotonic saline was injected using ultrasound guidance into both right and left pleural spaces and the measurements were repeated using standard increments until 1000 ml total volume was reached. No relationship was identified between mean distance and injected volume up to 100 ml. Thereafter, the mean distance increased in an approximately linear relationship with the cube root of fluid volume. There was a high correlation ( r ≥0.899) between the ultrasonographic measurement and fluid volume within individual dogs, but it was not possible to produce a useful equation to calculate absolute pleural fluid volume for new subjects. Nevertheless, ultrasonography may be used to semiquantitatively monitor pleural fluid volume, so that a decrease in the mean linear measurement obtained reflects a decrease in the total fluid volume.     

An agro-economic survey of the weeds and weeding practices in cassava (Manihot esculenta Crantz) in Colombia

A survey of weeds and weeding practices was carried out by a team of agricultural economists and agronomists on 283 farms in five Cassava growing regions of Colombia at three times during a cropping season. Seventy-one to 78% of all weed species present were broadleaved species. As cassava grew older, grass species were present to a greater and sedge species to a lesser relative frequency. Surprisingly Pteridiumaquilinum (L.) Kuhn was the most frequently listed species and Bidens pilosa L. and Cyperus rotundus L. were other frequent problems. Regional variations in the most frequently encountered species were found but several of the weeds were common to many zones. The most frequently encountered species did not usually have the highest plant populations. Most of the annual grasses, sedges and broadleaf weeds found can be controlled by currently recommended herbicides for cassava but further research is needed on Imperata cylindrica (L) Beauv., Melinis minutlftora Beauv., P. aquilinum and Sida spp. The average number of manual weedings was 3.3 per crop, occupying 48 man-days/ha which is 50% of the total labor requirements for cassava production, and more than one-third of the total costs. Reasons for not using herbicides were (1) relative costs of herbicides and labor. (2) lack of information, (3) lack of capital, (4) right herbicides were not available, and (5) herbicides were not available in small packages. This survey has usefully identified new field problems and has suggested further research programs to solve them.     

Natural radioactivity of Miami soils

An important part of man's radioactive environment is the natural radioactivity of soils. This radioactivity varies with soil type and withdepth in the soil profile. The relation between gross gamma activity and soil depth for a particular soil (Miami silt loam) is presented, together with a discussion of the contribution of K(40) and the uranium and thorium series and of the effects of fallout from bomb tests in increasing the radioactivity of a thin layer of surface soil.     

Storm-generated coral fragments - A viable source of transplants for reef rehabilitation

Coral reefs throughout the world have been damaged by storms, diseases, coral predators, temperature anomalies, and human activities. During the past three decades, recovery has been limited and patchy. Although a damaged coral reef cannot be restored to its original condition, interest in reef restoration is increasing. In a pilot project in the Caribbean (US Virgin Islands), storm-produced fragments of Acroporapalmata, A. cervicornis, and Porites porites were collected from donor reefs and transplanted to nearby degraded reefs. Sixty coral fragments were attached to dead-coral substrate (usually A. palmata skeletons), at similar depths from which they had been collected (1-3.5 m), using nylon cable ties. Seventy-five intact colonies were designated as controls. Study colonies were assessed at 6-month intervals for 2 years (1999-2001) and annually thereafter (through 2004). One-fourth of the 135 colonies and fragments monitored were alive at the conclusion of the 5-year study. Survival of control and transplanted A.cervicornis and P. porites was very low (median survival 2.4 and 1.8 years, respectively), with no significant differences between transplant and control colonies. Site and depth did not contribute significantly to A. palmata colony survival, but colony size and transplant/control status did. Probability of survival increased with colony size. Median survival for A. palmata was 1.3 years for transplant and 4.3 years for natural colonies when not controlled for size. A. palmata was the only viable candidate for reef rehabilitation. Storm swells were the primary cause of mortality.     

Healing of Sharp Incisions and Electroincisions in Dogs: A Comparative Study

Healing of incisions made by sharp blade and of those made by electroincision was compared. The electrosurgical unit used generated a wave form that closely resembled a square wave. Six paired incisions were made in the skin and external abdominal muscle fascia of 8 dogs by sharp blade and electroincision, and were sutured. One pair of incisions was made every other day in each dog; fascia and skin were examined at 2, 4, 6, 8, 10, and 12 days after incision. The presence of certain microscopic features was graded on an arbitrary scale of 0, 1, 2, and 3 for none, slight, moderate, and heavy, respectively; the grades were then averaged and compared. No differences were observed in the quantity of hemorrhage, capillaries, fibroblasts, and collagen and mature fibroblasts. More fibrin, necrosis, and polymorphonuclear leukocytes were observed following electroincision at 4, 6, 12, and 8 to 10 days, respectively. Considerably more edema was present following sharp incision from 4 to 12 days. The strength of wounds made by sharp incision was greater than the strength of those made by electroincision after day 6, but the two were almost identical by day 12. The data suggest that suture removal should be delayed until the 10th postoperative day, approximately 3 days later than is advised for sharp incision.     

Experimental Use of Fluoroalkyl Cyanoacrylate in Canine Urethral Anastomosis

The results of a study designed to evaluate a fluoroalkyl cyanoacrylate tissue adhesive as an adjunct to suture anastomosis of the severed canine pelvic urethra are presented. The urethral anastomotic sites were evaluated by contrast radiography, gross pathology, and histopathology. Urethral anastomosis resulted in a clinically functional urethra in all 6 control dogs (suture anastomosis) and 5 of the 6 test dogs (suture anastomosis plus adhesive). A severe stricture at the anastomotic site developed in 1 dog in the test group. Evidence of leakage was detected by contrast radiography in 1 dog of each group. Microscopic evidence of incomplete closure was detected in 4 control dogs and 2 test dogs. An extensive granulomatous inflammatory reaction was associated with use of the adhesive. The lower incidence of microscopic leakage observed in the test dogs was attributed to fibroplasia induced by the cyanoacrylate and not to the adhesive properties of the cyanoacrylate.     

The ecological life cycle of Thlaspi perfoliatum and a comparison with published studies on Thlaspi arvense

Thlaspi perfoliatum L. is an introduced winter annual that grows in waste places, but it is not a troublesome agricultural weed. Seeds are dormant at maturity in spring, afterripen during summer and germinate in autumn. Non-dormant seeds that fail to germinate in autumn are induced into secondary dormancy by low winter temperatures and cannot germinate the following spring. These seeds afterripen during summer and germinate in autumn if conditions are suitable. Vernalization is not an absolute requirement for flowering. However, it shortens the time to flowering, and vernalized plants produce many more flowers and seeds than non-vernalized plants. Results from studies on seed germination and flowering of T. perfoliatum are compared to published studies on the life cycle of Thlaspi arvense L., an introduced species that is a serious agricultural weed which behaves both as a winter and a summer annual.