Isolation and identification of a bovine adenovirus type 3 with an adenovirus-associated virus.

A bovine adenovirus with agglutinating activity was isolated from feedlot calves and classified as serotype 3. The agglutinating activity was shown to be the property of an adenovirus-associated virus (AAV). The AAV was isolated from the bovine adenovirus by isopycnic centrifugation in CsCl; the AAV had a density of 1.4 g/cm2. This AAV is serologically related to bovine AAV-TR-15, but is distinct from bovine parvovirus-1 and primate AAV types 1 to 4, using counterimmunoelectrophoresis and hemagglutination-inhibition.     

Isolation of bovine adenovirus type 7 from calves with pneumonia and enteritis.

Bovine adenovirus type 7 was isolated from a 10-month-old calf with fibrinopurulent pneumonia and from 2 newborn calves with pneumoenteritis. The viruses were isolated on calf lung and adrenal gland cell cultures and were identified as serotype 7 by immunoelectron microscopy and serum-neutralization tests.     

The use of n‐paraffin‐grown yeast as the main source of protein in diets for chicks

1. n‐Paraffin‐grown yeast and a mixture of soyabean meal and fish meal were compared in the net protein utilisation (NPU) test, and as protein supplements in diets for broilers up to 4 weeks of age.

2. The difference between the NPU values, 0.66 for yeast and 0.80 for the soyabean meal and fish meal mixture, could largely be attributed to the high nucleic acid content of the yeast.

3. Chicks given the diet containing yeast (190 g/kg) did not grow as rapidly as those given the soyabean meal and fish meal reference diet, and the reduced growth could only partly be explained by a marginal deficiency of methionine.

4. Food conversion efficiency with the yeast diet was improved by maize oil while responses to α‐tocopheryl acetate and sodium selenite were inconsistent.

5. Chicks grew well when yeast replaced fish meal in the mixture of soyabean meal and fish meal, and when fish meal (194 g/kg diet) was the sole protein supplement.     

Prophylactic use of antibiotics in surgery

"Sound and careful surgery is the sine qua non of wound management; antimicrobials are adjunctive." The key to successful use of prophylactic antibiotics in surgery is careful selection of cases and medication. There are no final rule or formulas that will always give optimal results. Listed below are some guidelines that may assis the clinician in determining the need and form of antimicrobial use. 1. The operation must carry a significant risk of bacterial contamination. Refined-clean and clean procedures should not be given prophylactic antibiotics. 2. Bacterial cultures should be taken when possible, and the medication used for prophylaxis should be effective against the organisms expected to be encountered. 3. Narrow spectrum antibiotics should be used to conserve the body's normal flora. Broad spectrum antibiotics needed to combat resistant infections should not be used for prophylaxis. 4. The antibiotic should be present in the wound in effective concentrations at the time of the incision and be maintained only as long as the risk of new bacterial contamination exists.     

Tolerance breaking by lymphocyte activating factor induced by Escherichia coli O138 lipopolysaccharide from homologous macrophages.

Following an antigenic dose of 10 microgram or a tolerogenic dose of 200 microgram of Escherichia coli O138 lipopolysaccharide (LPS), BALB/c mice were examined on day 14 for percentages of theta-bearing cells. A considerable increase in T cells was noticed in lymphocytes from tolerant draining lymph nodes, and furthermore these cells did not possess receptors for LPS when tested for rosette inhibition. However, when the supernatant from 1 X 10(7) macrophages, pretreated with 150 microgram LPS, was given to tolerant mice on day 7, by day 14 tolerance was found to be broken, anti-LPS IgG was present in circulation and the draining lymph node contained T cells specifically committed to LPS. The change from suppressor to helper T cell activity is discussed in relation to enhancement of the immune response.     

Differentiation of strains of bean common mosaic virus

Pathogenicity and symptom expression of seventeen described isolates of bean common mosaic virus (BCMV) and five previously unreported isolates were compared on many bean cultivars (Phaseolus vulgaris L.). From these cultivars, a standard set of differentials were assigned to nine groups with different disease reactions. The twenty-two virus isolates comprised seven strain (pathotype) groups, three of which were divided into two subgroups each. To promote international standardization in BCMV research, recommendations are given for test conditions and procedures, criteria for strain differentiation, and maintenance of differential cultivars and virus strains.Samenvatting Zeventien beschreven stammen van het bonerolmozaïekvirus en vijf niet geïdentificeerde isolaten (Tabel 1) werden bestudeerd op een uitgebreide reeks van toetsrassen. De meeste van deze toetsrassen waren in de literatuur als zodanig vermeld, maar door de desbetreffende onderzoekers waren vaak verschillende series toetsrassen gebruikt, hetgeen de onderlinge vergelijking van de stammen bemoeilijkte.De bedoeling van dit onderzoek was: vergelijking en indeling van de virusstammen, samenstelling van een standaard-toetsrassenserie en het ontwerpen en beschrijven van werden zowel in Wageningen als in Prosser, Washington, USA, uitgevoerd met dezelfde virusisolaten en dezelfde zaadmonsters van de toetsrassen.De toetsrassen konden op grond van hun differentiële reacties na inoculatie met de virusstammen worden ingedeeld in negen groepen. De rassen binnen een groep hebben hetzelfde resistentiespectrum t.o.v. een standaardserie virusstammen. Uit elke groep werden op grond van hun geschiktheid (duidelijkheid en reproduceerbaarheid van de symptomen) één of meer vertegenwoordigers gekozen, waaruit een standaardserie van toetsrassen werd samengesteld (Tabel 2).De 22 stammen en isolaten werden op grond van hun pathogeniteitsspectrum t.o.v. de standaardserie van toetsrassen ingedeeld in tien groepen en subgroepen (Tabel 1). De stammen en isolaten binnen een groep of subgroep hebben eenzelfde pathogeniteitsspectrum (Tabellen 4 en 6) en worden op grond daarvan als identiek beschouwd. De differentiële reacties tussen de rassen van de standaardserie en de virusstammen en-isolaten zijn vermeld in de Tabellen 3 en 5. Voorgesteld wordt om de naam van de eerstbeschreven stam van iedere groep te handhaven en de andere stammen in een groep of subgroep op te vatten als isolaten daarvan.De toetsmethodiek wordt uitvoerig beschreven om standaardisatie van de stammenidentificatie te bevorderen. Ter verklaring van de in de literatuur gevonden tegenstrijdigheden in de differentiële reactie van de toetsrassen wordt een negental mogelijke oorzaken genoemd, o.a. het gebruik van planten van toetsrassen die reeds vanuit zaad met een onbekende stam waren besmet en het gebruik van onzuivere virusstammen (mengisolaten).De auteurs stellen zich verantwoordelijk voor het distribueren (op aanvraag) van kleine zaadhoeveelheden van de toetsrassen en, op beperkte schaal, van in zaad aanwezige zuivere virusstammen aan onderzoekers die betrokken zijn bij de identificatie van de stammen van dit virus. Bovendien zal zaad van de standaardserie van toetsrassen worden gedeponeerd in het National Seed Storage Laboratory te Fort Collins, Colorado, USA, terwijl de virusstammen (in zaad) in bewaring worden gegeven bij de American Type Culture Collection te Rockville, Maryland, USA, waar ze beschikbaar zullen blijven voor verder onderzoek.     

In vitro effects of DDT analogs on trout brain Mg2+-ATPases: Inhibition kinetics

A continuous in vitro steady-state assay procedure was used to investigate the dependence of trout brain mitochondrial Mg²⁺-stimulated adenosinetriphosphatase specific activity on temperature and substrate concentration. The inhibition of enzyme activity by DDT was independent of substrate concentration. DDT and several analogs caused increases in the experimental activation energy and frequency factor of the enzyme-catalyzed reaction, which gave rise to a negative temperature coefficient of inhibition. It is suggested that DDT and other highly lipophilic compounds have the potential to allosterically affect membrane-bound enzymes by simply becoming a major lipoid component of the membranes.     

A study of liver function in rats with mirex-induced enlarged livers

The functional capacity of a mirex-induced, enlarged liver was studied in rats. The tests used were sulfobromophthalein clearance, hepatic cytochrome P-450 concentration, serum total protein concentration and electrophoretic pattern, serum total lipid concentration, serum glucose concentration, and the liver response to epinephrine. There was no indication of a loss of functional capacity in the enlarged liver. Sulfobromophthalein clearance and microsomal cytochrome P-450 concentration indicated an increase in total liver functional capacity. We conclude that mirex is not a direct hepatotoxin producing generalized parenchymal cell damage.