Pulling or drilling, does size or species matter? An experimental study of prey handling in Octopus dierythraeus ()

The influence of both predator and prey size on the shift from a pulling to a drilling predatory response was examined in the intertidal octopus Octopus dierythraeus, using an experimental program. Additionally, selective drilling, where particular regions of the prey are targeted, was examined for a variety of bivalve and gastropod prey. O. dierythraeus always initially attempted to pull bivalves apart. Shells that were eventually drilled were always subjected to significantly more pulling attempts than those that could be pulled apart, indicating that octopus are willing to expend more energy to access the flesh quickly. There was no defined threshold where bivalve size caused an octopus to switch from a pulling to a drilling response. Instead, there was a broad size range where the octopus could adopt either handling method and it varied for each individual. Octopus may only able to pull open bivalves before the molecular ratchet or ‘catch’ mechanism that many bivalves possess is engaged. This might explain the lack of a relationship between either octopus or bivalve size and the success of pulling, as it is likely that when the bivalves were presented to individual octopus they were either setting the ‘catch’ mechanism, or had already engaged it. O. dierythraeus demonstrated selective drilling on a variety of molluscan prey, with penetration sites differing between prey species. O. dierythraeus targeted the valve periphery, which was the thinnest part of the shell, therefore minimizing handling time. O. dierythraeus always drilled gastropods, but did not target the thinnest regions of the shells, with drill site varying according to the morphology of the prey. Elongate species with pronounced aperture lips were drilled in the apical region, close to the columella on the side of the opercula whereas nonelongate species were drilled immediately above the aperture. The location of drilling sites may represent a trade-off between targeting the most effective places to inject paralyzing secretions and the mechanically simplest places to drill.     

Use of a permanent tissue expander for breast reconstruction

The use of tissue expansion in breast reconstruction is a recognized alternative surgical approach. The second generation of tissue-expanding prostheses is the permanent reverse double-lumen expander. In a series of 100 breast reconstructions using a permanent tissue expander, the clinical benefits of producing a moderate degree of mound ptosis along with observed reduction in pain during expansion are discussed. Additional advantages to the use of the device are the cost savings realized, elimination of a second procedure and a second anesthetic exposure, and a high degree of patient acceptance and satisfaction. This study includes breast reconstruction following mastectomies for malignant and premalignant disease, as demonstrated in 75 delayed and 25 immediate reconstructions, with the longest follow-up being 3 years. Complications of infection (3 percent), significant capsular contracture (4 percent), and implant failure (3 percent) are the most frequent and major complications observed yet. In no instance was breast reconstruction rendered unachievable in the face of these complications. The demonstrated results achieved with permanent tissue-expanding prosthesis, complemented by the obvious benefits and a low rate of significant complications, endorse this method as a viable alternative approach in reconstructive breast surgery.     

Extracellular production of a heat-stable somatic antigen by Bacillus thuringiensis

Extracellular production of a heat-stable somatic antigen (HSSA) by Bacillus thuringiensis subsp. dendrolimus strain T84A1-A [flagellar (H) serotype 4a: 4b] was serologically detected. In Ouchterlony tests, the HSSA antiserum gave single precipitin lines against both untreated and heat-treated culture supernatants. These two precipitin lines fused completely. When colonies of strain T84A1-A were grown on nutrient agar plates containing the homologous HSSA antiserum, precipitin halos were formed around the colonies. Of 27 type strains of B. thuringiensis subspecies tested, only the type strains of B. thuringiensis subsp. sotto (H serotype 4a: 4b) and B. thuringiensis subsp. israelensis (H serotype 14) formed [precipitin halos on nutrient agar plates containing antiserum against the HSSA of strain T84A1-A.     

Purification and some properties of the methyl-CoM reductase of Methanothrix soehngenii

Abstract The methyl-CoM reductase from Methanothrix soehngenii was purified 18-fold to apparent homogeneity with 50% recovery in three steps. The native molecular mass of the enzyme estimated by gel-fitration was 280 kDa. SDS-polyacrylamide gel electrophoresis revealed three protein bands corresponding to M _r 63 900, 41 700 and 30 400 Da. The methyl-coenzyme M reductase constitutes up to 10% of the soluble cell protein. The enzyme has K _m apparent values of 23 μM and 2 mM for N -7-mercaptoheptanoylthreonine phosphate (HS- HTP = component B ) and methyl-coenzyme M (CH₃CoM) respectively. At the optimum pH of 7.0 60 nmol of methane were formed per min per mg protein.     

Continuous arteriovenous hemodialysis: an alternative therapy for acute renal failure associated with critical illness.

Critically ill patients often cannot tolerate conventional hemodialysis because of hemodynamic instability. Continuous arteriovenous hemofiltration provides control of fluid and electrolyte balance but is inefficient in the management of azotemia. Continuous arteriovenous hemodialysis (CAVHD) combines dialysis with hemofiltration. We performed 15 CAVHD treatments of 2 or more days'' duration in 12 critically ill patients aged 23 to 85 (mean 64.4) years who had acute oliguric renal failure as a component of multiple organ system failure and who were unsuitable for conventional hemodialysis. The total treatment time was 106 days. The serum creatinine and urea levels were controlled in all the patients during CAVHD. The ultrafiltrate losses were sufficient to allow appropriate nutrition and fluid administration and still maintain a negative fluid balance. Renal function returned in five patients (42%), of whom four survived to be discharged home. CAVHD is an effective means of managing acute oliguric renal failure in critically ill patients.