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Biomedical subjects

A Lund

Publications and source records attributed to A Lund.

At least 91 records · Page 5Linked to original sources

Desipramine in small doses induces antinociception in the increasing temperature hot-plate test, but not in the tail-flick test.

The data reported for the antinociceptive effect of tricyclic antidepressants are conflicting. In this investigation, the effect of acute intraperitoneal (i.p.) administration of desipramine (2 and 5 mg/kg) was studied in rats, using the tail-flick test with simultaneous measurement of tail-skin temperature, and the increasing temperature hot-plate test. A constant negative correlation between tail-flick latency and tail-skin temperature, as described earlier, was also found in this study. Different ambient temperatures influenced the results of the tail-flick test. At an ambient temperature of 24-25 degrees C, desipramine gave rise to an apparent antinociception in the tail-flick test, which was found to be caused by a relative fall in tail-skin temperature. At 21-22 degrees C, no change in tail-flick latency was found after the administration of desipramine. In the increasing temperature hot-plate test, however, a dose-dependent antinociceptive effect of desipramine was observed at both ambient temperatures. The strong influence of moderate differences in ambient temperature on the results of the tail-flick test may explain some of the conflicting results reported in the literature. Whenever this test is used, the temperature of the tail should be recorded and taken into account in the evaluation of the data.

Animals↗

The apparent hyperalgesic effect of a serotonin antagonist in the tail flick test is mainly due to increased tail skin temperature.

It has been suggested that reduced activity in raphe-spinal serotonergic systems induces hyperalgesia. In rats, the serotonin antagonist metergoline (0.5 mg/kg intraperitoneally) reduced tail flick latency by 0.92 sec (p less than 0.001) and increased tail skin temperature by 2.4 degrees C (p less than 0.001) when measured 50 min after injection. Multiple regression analysis with tail flick latency as dependent variable and tail skin temperature and metergoline/vehicle as independent variables revealed a highly significant effect of tail temperature on tail flick latency. The increase of tail skin temperature explained a reduction of tail flick latency of 0.64 of the 0.92 sec observed [B = -0.267 +/- 0.034, t(37)= -7.75, p less than 0.0001]. When the effect on tail skin temperature was taken into account, metergoline reduced tail flick latency by 0.28 sec [B = -0.284 +/- 0.114, t(37) = -2.50, p less than 0.05]. Metergoline (0.5 and 2.0 mg/kg) did not significantly alter plantar paw skin temperature or the response temperature in the increasing temperature hot plate test. Thus, the observed effect of metergoline on tail flick latency is primarily due to an effect on tail skin temperature. The possibility exists that the remaining effect of metergoline may be due to inadequate correction for the skin temperature change, and it is concluded that the study provide no clear evidence for a tonic inhibition of nociception by serotonergic systems.

Animals↗

An improved method for tail-flick testing with adjustment for tail-skin temperature.

The tail-skin temperature is an important factor in determining tail-flick latency to noxious radiant heat in rats and mice. A simple, non-invasive method for recording the tail-skin temperature during conventional tail-flick testing is described. The method is conveniently performed during conventional tail-flick testing. It does not require additional handling of the animals, and it is not stressful. The method utilizes a small-sized thermocouple which is brought in contact with the dorsal surface of the tail close to the area exposed to the radiant heat stimulus. A computer based system is used to record the temperature and control the tail-flick apparatus. Continuous monitoring of skin temperature showed that the temperature as measured 23 mm from the tip of the tail agreed well with skin temperature in the position where the beam was focused during tail-flick testing (13 mm from the tip). The skin temperature closer to the base of the tail (100 mm from the tip) showed considerably more deviation from the temperature 13 mm from the tip. Temperature measurements close to the heated area gave a higher degree of correlation between recorded temperature and tail-flick latencies than did temperature measurements closer to the base of the tail. These results provide further support for the contention that tail-skin temperature is an important factor when assessing nociception by means of the tail-flick test, and demonstrate that the temperature should be measured as close to the heated area as possible.

Animals↗

Effect of a shielded liner on new mastitis infection.

Results from a field trial involving 23 Norwegian dairy herds support the theory that deflector shields inserted into the teatcup liner can reduce the risk of intramammary infection. However, the effectiveness of this measure is questionable in cows already infected and in problem herds.

Animals↗

Rapid isolation of K88+ Escherichia coli by using immunomagnetic particles.

Superparamagnetic polymer particles precoated with sheep anti-mouse immunoglobulin G were coated with immunoglobulin G2 monoclonal antibodies to the K88 antigen of Escherichia coli (MAb-K88). These immunomagnetic particles (IMP) were used for isolation and identification of K88 antigen-positive (K88+) E. coli. The bacteria presenting the K88 antigen were easily isolated in almost pure culture from a mixed culture of five different O serogroups of E. coli. Nonspecific binding of K88 antigen-negative (K88-) E. coli to the IMP was not observed. The sensitivity of the test to detect K88+ E. coli was found to be 4,000 CFU/ml with fluorescence microscopy. When bacteria attached to the MAb-K88 IMP were grown on blood agar, about 20% of the initial number of CFU was recovered. The test is promising as a rapid method for isolation and identification of K88+ E. coli from a mixed culture.

Antibodies, Monoclonal↗

The role of antiepileptics in sudden death in epilepsy.

In a material of sudden, unexpected death of epileptic patients treated with one or more of the anticonvulsants phenobarbitone, phenytoin and carbamazepine we found subtherapeutic drug levels in half of the cases and lethal concentrations, mainly of phenobarbitone, in one third of the cases. The results illustrate the severe consequences of noncompliance in epilepsy, and stress the value of blood drug level control.

Adult↗

The causes of death in fire victims.

In 169 consecutive cases of autopsied fire victims about 50% had lethal levels of carboxyhemoglobin. Soot in the respiratory tract was found in about 90% of the cases. The age distribution of the fire victims showed significantly less persons in the 15-35-year group than should be expected according to the age distribution of the population, presumably due to greater agility of younger people. More than half of the fire victims had alcohol in the blood exceeding 0.05%, and alcohol intoxication should be considered accessary to many deaths in fire. The characteristic biphasic distribution of carboxyhemoglobin in fire victims together with other observations suggest that the principal causes of death are carbon monoxide followed by carbon dioxide poisoning and/or oxygen deficiency, while the influence of heat is considered to be of minor importance.

Adolescent↗

Differences in bindings to the GM1 receptor by heat-labile enterotoxin of human and porcine Escherichia coli strains.

Heat-labile enterotoxin producing strains of Escherichia coli were isolated from diarrheal faeces of humans and from the jejunum of pigs which had died of diarrhea. The heat-labile enterotoxin was assayed by three different enzyme-linked immunosorbent assays (ELISA). The first assay was based upon immunological cross-reactions between the heat-labile enterotoxins of E coli and Vibrio cholerae, the second on specific E coli heat-labile enterotoxin antibodies and the third on affinity of the toxin to the presumed cell membrane receptor, the ganglioside GM1. The heat-labile enterotoxins of human and porcine origin bound equally well to the same extent in the ELISA procedure, which utilized immunological cross-reactivity between the heat-labile enterotoxins of E coli and V cholerae. The reactivity, however, was quite different in the GM1-ELISA. The binding affinity was high between GM1 and enterotoxin produced by E coli strains of human origin, whereas the binding affinity was low for enterotoxin from porcine strains.

Animals↗

[Fatal poisoning].

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Barbiturates↗

Endogenous alcohol production by intestinal fermentation in sudden infant death.

In some cases of sudden infant death syndrome (SIDS) the intestinal flora was found to be dominated by Candida albicans. Microbiologic investigations of the various organs showed the occasional presence of different Candida species, but not in the form of massive growth as in sepsis. There is no basis to assume that the activity of yeasts, first of all of Candida albicans, is a contributory factor in the occurrence of SIDS. Candida albicans was shown to produce alcohol from glucose at a rate of maximally 1 mg of alcohol per gram of intestinal content per hour. It is concluded that the intestinal production of alcohol in vivo from cases showing a Candida albicans dominated intestinal flora will not be able to surpass the normal alcohol metabolizing capacity of the liver. Thus, measurable concentrations of alcohol in the blood from such cases cannot be expected.

Candida albicans↗

Swine dysentery: the influence of dietary vitamin E and selenium on the clinical and pathological effects of Treponema hyodysenteriae infection in pigs.

Twenty-four conventionally reared pigs were divided into four equal groups and fed a basic ration deficient in vitamin E and selenium. One group was given a supplement of vitamin E and selenium. One group was given a supplement of vitamin E, another received selenium and a third received both nutrients. No supplement was given to the control group. After the pigs had been fed the different diets for 59 days they were inoculated with a pure culture of Treponema hyodysenteriae They were subsequently observed for 22 days. The inoculation resulted in outbreaks of swine dysentery in all groups. The results indicated that the administration of vitamin E supplement alone to the pigs reduced the clinical effects of T hyodysenteriae only to a minor degree. On the other hand, supplementation with selenium, either alone or with vitamin E, had a more positive effect which was most clearly illustrated by a greater weight gain during the postinoculation period.

Animals↗