IMAGING DIAGNOSIS—RADIOGRAPHIC,ULTRASONOGRAPHIC, COMPUTED TOMOGRAPHIC,AND FLUOROSCOPIC APPEARANCE OF A DISTAL PELVIC LIMB ARTERIOVENOUS MALFORMATION IN A YOUNG GERMAN SHEPHERD DOG

A German shepherd puppy presented for evaluation of a suspected arteriovenous fistula on the distal aspect of the right pelvic limb. Radiographs demonstrated expansion and resorption of the tarsal and metatarsal bones, and ultrasound detected a vascular abnormality. Using computed tomographic angiography, a complex arteriovenous malformation (AVM) involving the distal tibia, tarsus, and the metatarsus and an osteochondritis dissecans (OCD) lesion of the talus were identified. Based on these findings, therapeutic limb amputation was performed. Fluoroscopic angiography, vascular casting, and dissection were then used to further characterize features of this previously unreported AVM with concurrent bony lesions and OCD.     

Neuropharmacological properties of Xylocarpus moluccensis

The methanolic extracts of the barks and pneumatophores of Xylocarpus moluccensis were assessed for their effects on the central nervous system (CNS) using a series of established pharmacological tests including pentobarbitone-induced sleeping time, open field, hole cross, hole-board and evasions tests in mice model. These extracts produced a dose-dependent reduction of the onset and duration of pentobarbitone-induced hypnosis, reduction of locomotor and exploratory activities in the open field, hole cross, head-dip and evasion tests. These results suggest that both the bark and pneumatophore extracts possess CNS depressant activity, the pneumatophore extract being more potent than the bark extract.     

The response of small mammals to natural and human-altered edges associated with Afromontane forests of South Africa

An increase in edge area reduces the effective size of habitat fragments and thus the area available for habitat-interior specialists. However, it is unclear how edge effects compare at different ecotones in the same system. We investigated the response of a small mammal community associated with Afromontane forests to edge effects at three different habitat transitions: natural forest to grassland (natural edge, structurally different vegetation types), natural forest to mature plantation (human-altered edge, structurally similar vegetation types) and natural forest to harvested plantation (human-altered edge, structurally different vegetation types). We predicted that edge effects should be less severe at natural ecotones and at similarly structured contiguous vegetation types than human-altered ecotones and differently structured contiguous vegetation types, respectively. We found that forest species seemed to avoid all habitat edges in our study area. Surprisingly, natural edges supported a less diverse small mammal community than human-altered forest edges. However, edge effects were observed deeper into native forests surrounded by mature alien plantations (and more so at harvested plantations) than into native forests surrounded by native grasslands. The net effect of mature plantations was therefore to reduce the functional size of the natural forest by creating a larger edge. We suggest that when plantations are established a buffer zone of natural vegetation be left between natural forests and newly established plantations to mitigate the negative effects of plantation forestry.     

Distribution of total 14C residue in egg yolk, albumen, and tissues following oral [14C]sulfamethazine administration to hens

The distribution of total 14C residues was studied in egg yolk and albumen after administration of either single or multiple oral dosages of [14C]sulfamethazine (SMZ). One day after a single dose of [14C]SMZ (121 mg of sulfamethazine, 2.42 x 10(7) dpm), the 14C residue concentration peaked in egg albumen and egg yolk with the concentration in the former >4-fold greater than in the latter. Three days postdose, the 14C residue concentration in the yolk was approximately 7-fold higher than in the egg albumen. A multiple dose of [14C]SMZ containing sulfamethazine mass equivalent of an average therapeutic dose (282 mg, 2.9 x 10(7) dpm) for chickens was also administered orally for six consecutive days to hens. A significantly reduced level of egg production was observed during the medication, and most of the hens stopped laying eggs after the last dose. The 14C residue concentrations peaked on the last day (sixth) of medication in egg albumen and yolk. The 14C residue concentrations were also measured in liver, muscle, blood, and plasma of chickens sacrificed at 1, 24, 48, and 72 h after the last dose. Highest concentrations of 14C residue were accumulated in liver followed by, in decreasing order, blood, plasma, and muscle.     

Overview of physical-chemical methods for determining aminoglycoside antibiotics in tissues and fluids of food-producing animals

A survey of literature is presented dealing with physical-chemical methods for the detection and quantitation of aminoglycoside antibiotics (gentamicin, streptomycin, dihydrostreptomycin, and neomycin) that are used in food-producing animals. Recent developments in cleanup and determinative procedures, particularly liquid chromatography, for these compounds in fluids and tissues are emphasized. Little research has been done on residues in tissues compared with other biological matrices. This review also covers the chemistry, general characteristics, tolerances, and withdrawal times for the approved uses of these antibiotics in animals that are used for food.     

Effect of ascorbic acid on seed germination of three halophytic grass species under saline conditions

Grasses on the Pakistani coast are moderately to highly salt tolerant and have potential for utilization as a cash crop. This study was designed to determine whether seed germination of three halophytic grasses (Phragmites karka, Dichanthium annulatum and Eragrostis ciliaris) could be improved by exogenous application of ascorbic acid (AsA) under saline conditions. Seeds of P. karka were germinated in varying concentrations of NaCl and AsA under different temperature regimes, and seeds of Dichanthium annulatum and Eragrostis ciliaris were germinated at optimal temperatures only. In P. karka, concentrations of AsA (5 and 10 mM) alleviated the salinity effects better at cooler and moderate thermo‐periods, whereas higher concentrations (20 mM of AsA) failed to improve germination under all temperature regimes. AsA was ineffective at a warmer thermo‐period (25/35°C). The rate of germination also increased at all thermo‐periods with the application of AsA except at 25/35°C under saline conditions. Application of AsA improved the germination of E. ciliaris seeds under saline conditions but was inhibitory for D. annulatum in comparison with the untreated control. The rate of germination followed the similar pattern as that of seed germination. Results indicate that AsA has the ability to partially alleviate the effect of salinity on seed germination of some grass species under optimal temperature regime.     

Marker residue determination of tritium-labeled ivermectin in the muscle of aquacultured largemouth bass, hybrid striped bass, and yellow perch following oral treatment

The residue depletion profiles of tritium-labeled ivermectin and its metabolites in the muscle of aquacultured largemouth bass (LMB), hybrid striped bass (HSB), and yellow perch (YP) following oral treatment are reported. Fish were administered 3H-ivermectin at the dose level of 0.1 mg/kg body weight (7-9 μCi) in a gel capsule via stomach tube. At each postdose withdrawal time, six fish of each species were sedated with buffered MS-222 and blood samples taken. Fish were then euthanized, and fillets with adhering skin (scales removed) and bile samples were collected. The muscle fillets were homogenized in dry ice to a fine powder. Aliquots of tissue, plasma, and bile were assayed for total radioactive residue (TRR). The homogenized muscle was extracted in acetonitrile or methanol followed by high-performance liquid chromatographic (HPLC) analysis to determine the presence of parent ivermectin and its potential metabolites. The highest TRR concentrations (ivermectin equivalents) of 53, 45, and 44 ng/g (ppb) were obtained on postdose day 1 for HSB, LMB, and YP, respectively. The TRR depleted most slowly in HSB to 25 ppb at day 91, followed by YP to 19 ppb at day 42 and then by LMB to 22 ppb at day 35. The total residue of ivermectin and its metabolites by HPLC analysis followed the same depletion pattern in the three species. Additionally, the depletion rate of TRR of 3H-ivermectin in the three species followed the pattern bile > plasma > muscle. The results further indicate that one of the polar metabolites of ivermectin could serve as a potential marker residue as an indication of use, rather than the parent ivermectin.