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Biomedical subjects

B Henriksson

Publications and source records attributed to B Henriksson.

14 recordsLinked to original sources

Efficacy of intramammary treatment with procaine penicillin G vs. procaine penicillin G plus neomycin in bovine clinical mastitis caused by penicillin-susceptible, gram-positive bacteria--a double blind field study.

The efficacy of intramammary treatments containing procaine penicillin G alone (treatment A) or a combination of procaine penicillin G and neomycin (treatment B) was compared in treating clinical bovine mastitis caused by gram-positive bacteria susceptible in vitro to penicillin G. Both treatments were supplemented with a single intramuscular injection of procaine penicillin G on the first day of treatment. The study was carried out using a double blind design on commercial dairy farms in Southern Finland. A total of 56 quarters were treated with treatment A and 61 with treatment B. The cure rates for both treatments were equal, which suggests that the use of the penicillin G-aminoglycoside combination does not increase the efficacy of the treatment over that achieved by using penicillin G alone in bovine clinical mastitis caused by penicillin-susceptible, gram-positive bacteria.

Animals↗

Inhalation of low concentrations of toluene induces persistent effects on a learning retention task, beam-walk performance, and cerebrocortical size in the rat.

The organic solvent toluene is widely used in industry. The threshold limit value for extended occupational exposure to toluene is presently set to 200 ppm in the United States. We have investigated the effect of an inhalation exposure of 80 ppm for 4 weeks (6 h/day, 5 days/week), followed by a postexposure period of at least 4 weeks, on behavior and brain features in the rat. Toluene exposure appeared to affect spatial memory, since toluene-exposed rats showed a longer time in the correct quadrant in a Morris swim maze. This effect may indicate that the exposed rats used their praxis strategy longer before they started to look for the platform elsewhere. Toluene-exposed rats showed trends for increases in both locomotion and rearing behaviors and a significantly reduced beam-walk performance. The area of the cerebral cortex, especially the parietal cortex, was decreased by 6-10% in toluene-exposed rats, as shown by magnetic resonance imaging of living rats and autoradiograms of frozen brain sections. The K(D) and B(max) values of the dopamine D(3) agonist [(3)H]PD 128907 were not affected by toluene, as measured in caudate-putamen and subcortical limbic area using biochemical receptor binding assays and in caudate-putamen and islands of Calleja using quantitative receptor autoradiography. Hence, previously demonstrated persistent effects by toluene on the binding characteristics of radioligands binding to both D(2) and D(3) receptors seem to indicate a persistent effect of toluene selectively on dopamine D(2) receptors. Taken together, the present results indicate that exposure to low concentrations of toluene leads to persistent effects on cognitive, neurological, and brain-structural properties in the rat.

Administration, Inhalation↗

Behavioural deficits in adult rats following long-term adrenalectomy.

Long-term adrenalectomy results in loss of neurones in the hippocampal formation of the adult rat. The effects of long-term adrenalectomy on spatial learning and exploratory behaviour in adrenalectomized (ADX), adrenalectomized normal weight gain (ADXNW), sham operated and naive control male Sprague-Dawley rats were investigated in this study. The ADX rats had significantly longer latencies in the Morris maze task compared to the other groups. In the open-field situation, as a novel finding, the ADX rats showed significantly lower rearing scores compared to other groups. These data indicate that long-term adrenalectomy causes impairment in spatial learning and explorative behaviour in the rat.

Adrenalectomy↗

Increased expression of brain-derived neurotrophic factor mRNA in rat hippocampus is associated with improved spatial memory and enriched environment.

Enriched environment has been shown to enhance learning and memory and to induce morphological changes in the hippocampus. We report that rats housed in an enriched environment showed improved performance in the Morris water maze and decreased spontaneous motor activity. Exposure to behavioural tests increased expression of the mRNA that encodes brain-derived neurotrophic factor in the hippocampus. This was not seen when rats subjected to impoverished housing were tested suggesting that environmental history of the animal is of importance to induce expression of brain-derived neurotrophic factor in the hippocampus that may promote neuronal changes related to learning and memory.

Analysis of Variance↗

Ecologic studies of mosquitoes and birds as hosts of Ockelbo virus in Sweden and isolation of Inkoo and Batai viruses from mosquitoes.

Field studies were conducted in central Sweden from 1983 through 1985 to obtain information on the etiologic agent of Ockelbo disease, described in Sweden in the 1960s and probably identical to Pogosta disease in Finland and to Karelian fever in the western USSR. Mosquitoes (63,644) collected during this 3 year period yielded 21 virus strains. Ockelbo virus isolations were from Culiseta morsitans (5 strains), Culex pipiens and/or Cx. torrentium (6 strains), and Aedes cinereus (3 strains). Inkoo (6 strains) and Batai (1 strain) viruses were recovered from Ae. communis. Blood samples collected March-May from migrating birds on the southeast and est coast of Sweden and in July and August from resident birds in east-central Sweden were tested for neutralizing antibody to Ockelbo virus. Antibody was not detected in 328 birds sampled during spring migrations. Two of 58 (3.4%) birds bled in July and 8 of 78 birds (10%) bled in August had antibody to Ockelbo virus. Ockelbo virus circulates in a mosquito-bird-mosquito cycle, with Cs. morsitans and Cx. pipiens and/or Cx. torrentium as enzootic vectors. Antibody was detected in passerine birds. Other classes of birds or other vertebrates were not sampled. Aedes cinereus may serve primarily to transmit virus to people. The role of other mosquito species as vectors for people is unknown.

Aedes↗

Seasonal activity of mosquitoes in an Ockelbo disease endemic area in central Sweden.

In the Sässman area, province of Hälsingland, Sweden, mosquitoes were sampled in 1983 from aquatic habitats, overwintering sites, cattle sheds, human bait, with UV-light traps, rabbit-, guinea-pig-, hen-, dove- and unbaited suction traps and similarly baited net traps. Anopheles beklemishevi, An. messeae, Aedes cantans, Ae. cataphylla, Ae. cinereus, Ae. communis, Ae. diantaeus, Ae. excrucians, Ae. hexodontus, Ae. intrudens, Ae. leucomelas, Ae. pionips, Ae. punctor, Ae. vexans, Culex pipiens, Cx. torrentium, Cx. territans, Culiseta alaskaensis, Cs. bergrothi, Cs. morsitans, Cs. ochroptera and Mansonia richiardii were recorded as new to the province. Data are presented on the ecology including seasonal abundance and seasonal blood-feeding activity of each species. Ockelbo disease, caused by a virus indistinguishable from Sindbis virus, is prevalent amongst humans in the study area. The ecological and behavioral potential of species of Culex, Culiseta and Aedes to transmit the virus is discussed.

Animals↗