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Biomedical subjects

S M Kerr

Publications and source records attributed to S M Kerr.

25 records · Page 2Linked to original sources
PubMed1988

Excess antisense RNA from infectious recombinant SV40 fails to inhibit expression of a transfected, interferon-inducible gene.

SV40-based infectious virus constructs were used to produce a high copy number of full-length antisense RNA in essentially every cell in a population. Chloramphenicol acetyltransferase (CAT) cDNA was placed in either the sense or antisense orientation relative to the SV40 early promoter in helper-free recombinant virus. RNA synthesized at high levels from the antisense virus was without effect on the expression of a stably-transfected CAT mini-gene controlled by an interferon-inducible promoter in monkey CV1 and large T antigen-expressing tsCOS cells. In double infection experiments the antisense RNA was similarly without effect on expression from CAT cDNA placed in the sense orientation in a second virus vector. No activation of the ppp(A2'p)nA(n greater than or equal to 2) system was observed after interferon treatment in either type of experiment. There was no evidence, therefore, for the formation of double-stranded (ds)RNA. It can be concluded that a large excess of a full-length antisense RNA is not necessarily sufficient to cause inhibition of gene expression even when interferon treatment is used to enhance any effect of dsRNA.

Acetyltransferases↗
PubMed1985

Novel 2',5'-oligoadenylates synthesized in interferon-treated, vaccinia virus-infected cells.

2-5A[ppp(A2'p)nA] and related materials accumulate to greater than micromolar concentrations in vaccinia virus-infected HeLa cells and in interferon-treated, vaccinia-infected HeLa, CV1, and L929 cells even when virus replication is not inhibited. A variably complex mixture of authentic 2-5A (n = 2 to 4), nonphosphorylated cores [(A2'p)nA; n = 2 to 5], and additional compounds of unknown structure was observed.

Adenine Nucleotides↗
PubMed1984

Hyperthermia, Na+K+ATPase and lactic acid production in some human tumour cells.

When HeLa cells are exposed to brief heat shock at 45 degrees C there is a reduction in the cellular level of Na+K+ATPase. Return of the cells to the normal growth temperature of 37 degrees C leads to a partial restoration of enzyme activity. The pattern of this recovery of activity suggests that it may be associated with the induction of heat shock proteins. Indeed other means of heat shock protein induction such as continuous heat treatment at 42 degrees C, or treatment of cells at 37 degrees C with sodium arsenite, leads to elevated levels of Na+K+ATPase activity and alterations in the kinetic properties of the enzyme. Continuous hyperthermia at 42 degrees C led to increased lactate production which could be blocked with ouabain suggesting that effects on Na+K+ATPase activity could partly influence glycolysis. A number of other human and hamster cells also showed increased lactate production at 42 degrees C and also an inhibition of lactate production by ouabain. Whilst incubation of HeLa cells with cyanide had little effect on glycolysis at 37 degrees C elevation of the temperature to 42 degrees C (or 45 degrees C), in the presence of cyanide, impaired glycolysis. The possible role in this phenomenon, of an unusual oxygen-sensitive isoenzyme of lactate dehydrogenase, expressed in human cancers, is discussed.

Animals↗
PubMedDate not supplied

Characterization of an avian cholera epizootic in wild birds in western Nebraska.

Avian cholera killed an estimated 2500 birds in western Nebraska and eastern Wyoming from 28 November 1985 to late January 1986. Wild mallards (Anas platyrhynchos) suffered the most losses. Other wild waterfowl, wild turkeys (Meleagris gallopavo), a few domestic fowl, and a bald eagle (Haliaeetus leucocephalus) also died. Pasteurella multocida serotype 1 was the predominant isolate from these carcasses. Cold, wet weather persisted throughout the outbreak, but daily losses in the flock of 50,000 mallards using the area were low. Pasteurella multocida was isolated from nasal swabs of 35 of 37 cattle from a feedlot in which many of these mallards were feeding. Eighty percent of the cattle isolates had antigenic characteristics of serotype 3 or serotype 3 with cross-reactivity. Isolates from wild mallards, wild turkeys, and the bald eagle were virulent to game-farm mallards when inoculated subcutaneously, but P. multocida isolates from cattle were not.

Animals↗
PubMedDate not supplied

Lead poisoning in common loons (Gavia immer).

Two emaciated common loons (Gavia immer) were believed to have died of lead poisoning when fragments of fishing lines and lead sinkers were discovered in their stomachs. Later a third emaciated loon, which had only the remnants of fishing line in its stomach, was suspected of being a possible lead-poisoning victim when all other test results were negative. The liver lead levels in the first two loons were 20.6 ppm and 46.1 ppm (wet weight), and the level in the third was 38.52 ppm (wet weight). Thirteen common loons dying of other causes had liver lead levels of less than 1 ppm (wet weight).

Animal Population Groups↗
PubMedDate not supplied

Epizootic of coccidiosis in free-flying lesser scaup.

A coccidiosis epizootic has occurred in lesser scaup (Aythya affinis) at Bluestem Reservoir in eastern Nebraska during the spring in each of three recent years: 1976-1978. Losses peaked during the period from mid-March through April. As much as 29% of the peak population of scaup using the reservoir died. Necropsies of 72 of the nearly 1390 scaup that died revealed destruction and sloughing of the intestinal mucosa and associated hemorrhaging. Fibrinonecrotic cores were frequently found in the intestinal lumens. Scrapings from the intestinal mucosal contained massive numbers of oocysts of the coccidian Eimeria aythyae. This is the first report of recurrent epizootics of coccidiosis in freeflying waterfowl.

Animals↗