Centrifugal Fibers in the Chick Retina

This work is a morhological study of the centrifugal fibers in the chick retina. We have classified these fibers in two types: type I centrifugal fibers and type II centrifugal fibers. Type I centrifugal fibers constitute a new model of axonic terminal in the birds retina. These fibers terminate exclusively in the inner plexiform layer where they show long tangential trajectories. Type II centrifugal fibers are coincident with classical ones previously described in the avian retina. With the Golgi method we describe new levels of terminations of these type II centrifugal fibers.     

The Effect of R Factor Transfer on Bacterial Growth Rates an in Vitro Study

It has been studied whether R factor transfer had an inhibitory effect on the growth rate of Escherichia coli in mixed cultivation. A total of 39 antibiotic resistant E. coli strains were grown together with E. coli K12 W 3132 as prospective recipient. Thirteen crosses turned out successfully. When comparing generation times for these crosses with those of negative crosses no difference could be demonstrated. This, however, does not exclude that R factor transfer impairs bacterial growth capacity at a level which can not be detected in a short-term experiment.     

Rectal transmission of bovine leukemia virus in cattle and sheep

Bovine leukemia virus (BLV) was transmitted by rectal inoculation of BLV-infective whole blood into cattle and sheep. Two cows and 2 sheep each were given 500 ml and 50 ml of blood, respectively, by rectal infusion. Two sheep which served as positive controls each were given 1 ml of the same blood, IV. All animals became seropositive to BLV by postinoculation week 5. Although relatively large volumes of blood were used for rectal inoculation, a base line for infectivity was established for the rectal route.     

Mode of action of thiocyanates and iodides in aminotriazole formulations

Ammonium thiocyanate ( I ) was shown to inhibit the oxidation of aminotriazole (3-amino-1,2,4-triazole) in two free-radical generating systems: (a) riboflavin photo-sensitised oxidation; and (b) oxidation by hydroxyl radicals. Evidence from in-vitro studies is presented to show that I could enhance aminotriazole performance by being preferentially oxidised within the leaf, thereby preventing aminotriazole free-radical formation and subsequent conjugation with amino acids and other compounds. This opens up the possibility of a whole new range of additives which could enhance translocation by inhibiting free-radical reactions. A comparison of possible inhibitors revealed that cyanides, iodides and perhaps bromides may be of use in this respect. In addition to inhibiting free-radical reactions, I and potassium iodide ( II ) were shown to have a considerable effect on the uptake of aminotriazole by bean leaves (Phaseolus vulgaris var. Canadian Wonder). In the absence of additives, uptake of aminotriazole was negligible (1.8%); in the presence of a 1:1 molar ratio of I or II , uptake of aminotriazole was increased to 36.6% and 54.2% respectively. At a 3:1 molar ratio of additive:aminotriazole, the respective figures were 63.5% and 81.0%. II appeared to be the more efficient of the two additives at higher humidity. However, the results and observations indicated that the situation may be reversed under low-humidity conditions.     

Managing stress in veterinary students

The process of obtaining a veterinary medical education creates a number of potential cognitive, emotional, physical, interpersonal, and developmental stressors for veterinary students. Although most universities offer stress management interventions for their students, these programs are often directed toward undergraduate students or non-veterinary graduate students, whose educational programs differ significantly from those of veterinary students. There is a need for specific stress management programs tailored to the needs of veterinary students. This article summarizes research drawn from the psychology, medical, and veterinary medical literature about the causes of stress that veterinary students experience. Interventions are discussed, and several Oregon State University (OSU) programs and liaisons are described. Stress management resources are suggested.     

Survival times in dogs with right atrial hemangiosarcoma treated by means of surgical resection with or without adjuvant chemotherapy: 23 cases (1986-2000)

OBJECTIVE: To determine survival times in dogs with right atrial hemangiosarcoma treated by means of pericardectomy and tumor resection, with or without adjuvant chemotherapy, and identify complications associated with treatment. DESIGN: Retrospective study. ANIMALS: 23 dogs. PROCEDURE: Dogs were included only if the diagnosis was confirmed histologically. RESULTS: The most common initial complaints included acute collapse (8 [35%] dogs), anorexia or inappetence (8 [35%]), and lethargy (8 [35%]). The most common physical examination abnormalities included muffled heart sounds (12 [52%] dogs), tachycardia (7 [30%]), and weak pulses (7 [30%]). Postoperative complications developed in 12 (52%) dogs; however, most complications were minor. Twenty (87%) dogs were discharged from the hospital. Survival time was significantly longer in the 8 dogs that received adjuvant chemotherapy (mean, 164 days; median, 175 days) than in the 15 dogs that did not receive chemotherapy (mean, 46 days; median, 42 days). Dogs that received chemotherapy were significantly younger and had significantly lower WBC counts than did dogs that did not receive chemotherapy. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that in dogs with right atrial hemangiosarcoma, surgical resection of the tumor was associated with a low complication rate and complications that did arise typically were minor. In addition, use of adjuvant chemotherapy following resection was associated with significantly longer survival times, compared with resection alone.     

Preliminary results on detection of maize treated with electrons for seed dressing and according decontamination and infestation

Saatgut und Getreide kann mit niederenergetischen Elektronen (<300 kev) oder=" hochenergetischen=" elektronen=" (1–10 mev)=" wirksam=" behandelt=" werden,=" um=" mikroorganismen=" und=" insekten=" abzutöten.=" in=" dieser=" vorläufigen=" studie=" wurde=" mais=" mit=" niederenergetischen=" (125 kev)=" und=" hochenergetischen=" elektronen=" (10 mev)=" behandelt.=" um=" diese=" elektronenbehandlung=" nachzuweisen,=" wurden=" verschiedene=" verfahren=" eingesetzt:=" photostimulierte=" lumineszenz=" (psl),=" thermolumineszenz=" (tl)=" und=" dna-kometentest.=" für=" diese=" drei=" nachweismethoden=" existieren=" bereits=" europäische=" normen=" und=" sie=" sind=" als=">Allgemeine Codex Methoden zum Nachweis bestrahlter Lebensmittel etabliert. Die Ergebnisse zeigen, dass PSL und TL geeignete Verfahren sind, um sowohl eine Behandlung von Mais mit niederenergetischen als auch mit hochenergetischen Elektronen zu erkennen. Der DNA-Kometentest erwies sich als weniger geeignet: die Behandlung mit niederenergetischen Elektronen konnte—wie erwartet—nicht nachgewiesen werden. Die Behandlung mit hochenergetischen Elektronen konnte bei einer Maissorte erkannt werden, jedoch nicht bei einer anderen Sorte.