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Biomedical subjects

L Andersson

Publications and source records attributed to L Andersson.

535 records · Page 30Linked to original sources
PubMedDate not supplied

A method for studying the effects of neurochemicals on long-term compensation in unilaterally labyrinthectomized rats.

A new method has been developed to study the influence of drugs and toxicants on long-term recovery of dynamics in the horizontal vestibulo-ocular reflex of the rat after hemilabyrinthectomy (HL). HL was performed by injecting sodium arsanilate into the middle ear. The lesion was confirmed by histology. Eye movements elicited by sinusoidal vestibular stimulation, in both light and darkness, were recorded by a search-coil technique and then analyzed by a computer program created with virtual instrument soft-ware, which calculated the gain of the slow-phase velocity (SPV) and the saccades para-meters (frequency, amplitude, and peak velocity) to the lesioned side and to the intact side separately. During the 2-10 week period after HL, repeated analysis of the spontaneous long-term recovery of such parameters revealed a slight but significant reduction of the post-HL asymmetry between SPV gain to the lesioned side and to the intact side. During the follow-up period, a post-HL increase of the phase lead remained unchanged. The reduced number of saccades/min was not completely restored. To test the usefulness of the experimental model for neurochemical investigation of such adaptation, we administered baclofen and toluene to rats 8-12 wk after hemilabyrinthectomy. Baclofen, a specific GABAB agonist, immediately restored the symmetry of SPV gain. By contrast, toluene, which has some effects on the central vestibular system that are related to GABAB transmission, aggravated the asymmetry in both the SPV gain and the number of saccades. We suggest that the experimental model would be useful for studying neurochemical mechanisms in vestibular adaptation processes.

Adaptation, Physiological↗
PubMedDate not supplied

Genetic diversity of eleven European pig breeds.

A set of eleven pig breeds originating from six European countries, and including a small sample of wild pigs, was chosen for this study of genetic diversity. Diversity was evaluated on the basis of 18 microsatellite markers typed over a total of 483 DNA samples collected. Average breed heterozygosity varied from 0.35 to 0.60. Genotypic frequencies generally agreed with Hardy-Weinberg expectations, apart from the German Landrace and Schwäbisch-Hällisches breeds, which showed significantly reduced heterozygosity. Breed differentiation was significant as shown by the high among-breed fixation index (overall F(ST)= 0.27), and confirmed by the clustering based on the genetic distances between individuals, which grouped essentially all individuals in 11 clusters corresponding to the 11 breeds. The genetic distances between breeds were first used to construct phylogenetic trees. The trees indicated that a genetic drift model might explain the divergence of the two German breeds, but no reliable phylogeny could be inferred among the remaining breeds. The same distances were also used to measure the global diversity of the set of breeds considered, and to evaluate the marginal loss of diversity attached to each breed. In that respect, the French Basque breed appeared to be the most "unique" in the set considered. This study, which remains to be extended to a larger set of European breeds, indicates that using genetic distances between breeds of farm animals in a classical taxonomic approach may not give clear resolution, but points to their usefulness in a prospective evaluation of diversity.

Journal Article↗
PubMedDate not supplied

A high-density linkage map of the RN region in pigs.

The porcine RN locus affects muscle glycogen content and meat quality. We previously mapped the RN locus to chromosome 15. This study describes the identification of polymorphisms for four class I and four class II markers located in the RN region. Resource families were genotyped with F-SSCP markers (fluorescent single strand conformation polymorphism) and microsatellite markers. Subsequent multipoint linkage analysis revealed the order FN1-IGFBP5-S1000-S1001-IL8RB-VIL1-RN-Sw936-Sw906. The gene order is identical to the previously reported porcine RH map of the same region. The described map will facilitate positional cloning of the RN gene.

Journal Article↗
PubMedDate not supplied

Effects of adriamycin and hyperthermia on cellular uptake of [3H]thymidine and its significance for the incorporation into DNA.

Inhibition of the salvage DNA synthesis was studied in ascites tumour cells up to 240 min at moderately increased temperatures of 39 degrees C, 40.5 degrees C and 43 degrees C alone or in combination with adriamycin (ADR). Hyperthermia and ADR acted additively on salvage DNA synthesis. The [3H]thymidine (TdR) incorporation was strongly related to the cellular uptake of [3H]TdR. In order to evaluate the significance of the decrease in [3H]TdR uptake for the incorporation into DNA, the thymidine kinase (TK) has also been studied. TK activity started to decrease at a temperature of 39 degrees C, probably due to inhibition of translation and/or transcription of the enzyme, and was almost completely inhibited at 43 degrees C. ADR did not affect TK activity. Inhibition of DNA synthesis by aphidicolin neither decreased the ability of the cell to take up [3H]TdR nor the ability to affect TK activity. We concluded that moderate increases in temperature alone, or in combination with ADR, inhibit salvage DNA synthesis by inhibition of TdR uptake, possibly due to inhibition of phosphorylation; ADR, on the contrary, inhibits TdR uptake by other mechanisms such as changes in membrane function.

Animals↗
PubMedDate not supplied

The effect of two glucocorticoids on plasma glucose and milk production in healthy cows and the therapeutic effect in ketosis.

In a cross-over study of six clinically healthy cows in early lactation, injection of 10 mg dexamethasone isonicotinate caused significantly increased plasma glucose for six days and significantly decreased milk yield for one day. The corresponding effects of 10 mg dexamethasone phosphate + 20 mg dexamethasone phenylpropionate lasted for at least nine and seven days, respectively. The therapeutic effect in bovine ketosis of the two preparations was measured by means of analysis of acetone plus acetoacetate in milk sampled daily during eight days post treatment. Acetone plus acetoacetate in milk from cows given dexamethasone phosphate + dexamethasone phenylpropionate (n = 11) decreased to normal levels and from the fourth day after treatment was significantly lower than in cows given dexamethasone isonicotinate (n = 12).

Animals↗
PubMedDate not supplied

A linkage group composed of three coat color genes and three serum protein loci in horses.

The equine coat color genes chestnut (e) and roan (Rn) have been tested for linkage to 15 protein and blood group loci. Data showing close or fairly close linkage to the serum albumin locus (Al) and loose linkage to the serum esterase locus (Es) for both e and Rn are presented. This means that three coat color genes (To, e and Rn) and three serum protein loci (Al, Gc, and Es) are linked in the same linkage group. The gene order can tentatively be written Al, Gc, Rn, To-e-Es. The implications of the results for studies on coat color inheritance in horses are discussed. The possibility of using electrophoretic markers when testing hypotheses of allelism between coat color genes is suggested. The linkage of e and Es in the horse is proposed to be homologous to the loose linkage of the extension locus (e) and a cluster of esterase loci on chromosome 8 in the mouse, and on linkage group IV in the rabbit. Designations for the known autosomal linkage groups in the horse are suggested.

Animals↗
PubMedDate not supplied

Chronic copper toxicosis in sheep.

Some spontaneous cases of chronic copper toxicosis, that occurred in ewes of about 3--4 years of age during the period 1974--1976, were investigated. The diagnosis based on clinical and pathoanatomical alterations was substantiated further by demonstration of considerably elevated copper and iron content in the liver andkidneys of the affected sheep. Texel being a heavy breed seems to have suffered most possibily on account of having ingested relatively high amount of copper by way of consuming much more food at one time as compared to sheep of mixed breed. Besides breed predisposition and other possible contributing factors like stress, the possibility of increased use of commercial feed with supplementary copper and concentrates in sheep ration resulting in high risks of cummulative poisoning is discussed.

Animal Feed↗
PubMedDate not supplied

Hemorrhage in the floor of the mouth during implant placement in the edentulous mandible: a case report.

This report describes a life-threatening hemorrhage in the floor of a patient's mouth during routine implant placement in the anterior mandible. Airway obstruction caused by hematoma development resulted in acute nasotracheal intubation and subsequent surgical intervention. Surgical, radiographic, and anatomic considerations to prevent severe bleeding are discussed. An extraoral submental approach in cases with large sublingual hematomas is recommended. An outpatient should be treated in or close to a hospital where these complications can be dealt with promptly and effectively.

Aged↗