Nucleotide sequence of the Rasheed rat sarcoma virus oncogene: new mutations

The nucleotide sequence of the oncogene of the Rasheed strain of rat sarcoma virus was determined. The oncogene (Ra-v-ras) encodes a 29,000-dalton (p29) transforming protein. This protein is distinct from the immunologically related 21,000-dalton protein (p21) of the Harvey murine sarcoma virus in its amino terminus and in having additional mutations in its carboxyl terminus. Although the functional significance of these changes is unknown, they appear to occur only in rat sarcoma virus.     

Insecticidal activity of the pyrethrins and related compounds. Part XIV: Selectivity of pyrethroid insecticides between Ephestia kuhniella and its parasite Venturia canescens

Relative potencies for 20 pyrethroids against the Mediterranean flour moth Ephestia kuhniella, and its hymenopterous parasite Venturia canescens, show a wide range of selectivity factors (2-140), indicating the possibility of identifying compounds with selectivity favouring the survival of beneficial parasites rather than pest hosts.     

Jugular venous prosthesis on the horse: A preliminary report

Woven dacron vascular prostheses^a were implanted in 6 horses to replace segments of external jugular veins. Anticoagulant therapy using sodium heparin and coumadin was done postoperatively. Clotting profiles and red blood cell counts were determined by measuring activated partial thromboplastin time (APTT), one stage prothrombin time (OSPT), and packed cell volume (PCV). The horses were observed postoperatively for 4 to 38 days. Real time ultrasonography was used to monitor patency of the prostheses. All grafts remained patent during the observation period, although 3 cases of septic thrombosis were seen at necropsy.     

Magnetocardiography of direct currents: S-T segment and baseline shifts during experimental myocardial infarction

Magnetocardiograms with a bandwidth of 0 to 40 hertz were recorded from intact dogs undergoing myocardial infarction. This was done with a superconducting magnetometer in a magnetically shielded room. The purpose was to look for the steady currents of injury from the heart which supposedly produce much of the S-T segment shifts during infarction. These heart currents cannot be measured with surface electrodes because of direct-current interference from other sources, such as from the contact potential between electrode and skin. The magnetocardiograms showed both S-T segment shifts and direct currents as a result of infarction. However, they also showed that the S-T segment shifts were not produced by the direct currents. It is unlikely that these direct currents originated from the infarcted area, and their exact origin is not yet known.     

Evaluation of models used to assess the fate of chemicals in aquatic systems

Five reference chemicals, 2,5,4′-trichlorobiphenyl (3-CB), chloroform, parathionmethyl (MEP), pentachlorophenol (PCP) and 3,4-dichloroaniline (DCA), were applied to experimental outdoor ponds by sub-surface injection. Samples of water, sediment and vegetation were removed and analysed for residues at various intervals after treatment. The fate of these chemicals in the ponds was predicted through the use of process analyses and mathematical models. The predicted rates of loss were compared with experimental observations. Data obtained for 3-CB were fitted to a three-compartment model and this was used to calculate the rates of transport between water and sediment, and between water and vegetation. These processes are primarily dependent on turbulent mixing. In experiments with MEP it was shown that biodegradation was primarily associated with bacterial populations in the sediment rather than with those suspended in the water. The rate of biodegradation in sediment was relatively fast and there was no detectable lag phase. The sediment could therefore be considered a sink for MEP and the overall rate of loss of the latter was dependent on its rate of transport to the sediment. In an experiment with chloroform there was reasonably good agreement between predicted and observed rates of evaporation. However, observed rates were always greater than predicted rates, suggesting a systematic bias that may warrant further investigation. In experiments with PCP and DCA there was good agreement between predicted and observed rates of phototransformation.     

COMPUTED TOMOGRAPHIC CHARACTERISTICS OF COLLATERAL VENOUS PATHWAYS IN DOGS WITH CAUDAL VENA CAVA OBSTRUCTION

Collateral venous pathways develop in dogs with obstruction or increased blood flow resistance at any level of the caudal vena cava in order to maintain venous drainage to the right atrium. The purpose of this retrospective study was to describe the sites, causes of obstruction, and configurations of venous collateral pathways for a group of dogs with caudal vena cava obstruction. Computed tomography databases from two veterinary hospitals were searched for dogs with a diagnosis of caudal vena cava obstruction and multidetector row computed tomographic angiographic (CTA) scans that included the entire caudal vena cava. Images for each included dog were retrieved and collateral venous pathways were characterized using image postprocessing and a classification system previously reported for humans. A total of nine dogs met inclusion criteria and four major collateral venous pathways were identified: deep (n = 2), portal (n = 2), intermediate (n = 7), and superficial (n = 5). More than one collateral venous pathway was present in 5 dogs. An alternative pathway consisting of renal subcapsular collateral veins, arising mainly from the caudal pole of both kidneys, was found in three dogs. In conclusion, findings indicated that collateral venous pathway patterns similar to those described in humans are also present in dogs with caudal vena cava obstruction. These collateral pathways need to be distinguished from other vascular anomalies in dogs. Postprocessing of multidetector‐row CTA images allowed delineation of the course of these complicated venous pathways and may be a helpful adjunct for treatment planning in future cases.     

Molecular identification of Trogoderma granarium (Coleoptera: Dermestidae) using the 16s gene

The Khapra beetle, Trogoderma granarium Everts, is a global pest species of stored grain products. Accurate identification of Trogoderma specimens trapped within stores of grain is critical to surveillance and exclusion efforts for the Khapra beetle. To enhance diagnostic capacity, we report PCR-based diagnostic assays for Khapra beetle identification. Three methods such as conventional PCR, real-time PCR, and DNA sequencing are reported for the diagnosis of Trogoderma specimens captured within the U.S. All three methods discern the Khapra beetle based on variation in fragments of 16S mitochondrial DNA. To examine PCR assay stringency, ten native or introduced Trogoderma species and two Megatoma species were also examined. These DNA-based assays provide reliable identification of T. granarium regardless of condition, life stage, or taxonomic expertise of the investigator.     

Experimental Techniques for Laboratory Investigation of Clay Colloid Transport and Filtration in a Stream with a Sand Bed

The exchange of kaolinite clay between a stream and its associated sand bed was investigated in a recirculating flume. Bedforms at the sediment-water interface result in two bed-exchange mechanisms: the bedform shape induces an advective flow through the bed (‘pumping’), and dune propagation causes the trapping and release of pore water (‘turnover’). Chemical and electrostatic interactions then result in filtration of clay by the bed. In order to allow modeling of chemical effects, all flume materials must have defined chemical parameters. This required improvements in the flume water supply, construction of sand-washing equipment, and the use of defined clay and sand preparation procedures.Flume experimental result-, indicate that clay is extensively trapped by the bed. Advective pumping tends to carry clay to the deep bed where it can be permanently trapped, while turnover tends to continuously mix the upper layers of the bed, hindering penetration to the deep bed.