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Biomedical subjects

B Bjorvatn

Publications and source records attributed to B Bjorvatn.

At least 55 records · Page 3Linked to original sources
PubMed1994

Effects of the selective 5-HT1B agonist, CGS 12066B, on sleep/waking stages and EEG power spectrum in rats.

Sleep/waking stages and EEG power spectra were studied in rats for 8 h following intraperitoneal administration of CGS 12066B, a selective 5-HT1B agonist. Waking was increased and rapid eye movement (REM) sleep decreased in a dose-dependent manner. Total slow-wave sleep (TSWS) was reduced, but only in the first 2 h period. The latencies to REM sleep and stable sleep were increased dose-dependently. The drug also induced profound behavioural changes that may account for some of the sleep/waking changes. EEG power densities in waking and TSWS were reduced dose-dependently from 7 to 20 Hz after CGS 12066B, suggesting a tendency towards general deactivation. The increase in waking together with a general deactivation suggest complex effects of CGS 12066B on the sleep/waking axis.

Journal Article↗
PubMed1993

Dietary pattern and state of nutrition among children in drought-prone areas of southern Ethiopia.

To assess dietary habits and nutritional state in drought-prone areas of southern Ethiopia, we studied 334 households in a pastoral and 282 in an agricultural community. Milk and cereals were the main sources of food among children of the pastoral Boran in Dubluk, while cereals with limited supplements of animal products or legumes formed the main sources of food among children of the agricultural population of Elka in the Rift valley. Of the children in Elka, 54.9% were stunted, as compared with 19.5% among children in Dubluk. Also, stunting occurred at an earlier age among the Elka children. Prevalences of wasting were less than 5% in both communities. Improvement in the state of nutrition of the pastoral children followed soon after the main rains, but occurred later and after the main harvest among the agricultural children. In contrast to arm circumference, the weight-for-height measure showed marked seasonal variation. Socio-economic factors, such as family wealth and crowding, significantly influenced the state of nutrition among the children. Nutritional recovery following the prolonged drought among the agricultural children was slow and associated with families acquiring more wealth.

Anthropometry↗
PubMed1993

Nutritional status and risk of infection among Ethiopian children.

This is a prospective study on the possible association between protein energy malnutrition and risk of infection in a pastoralist and in an agricultural community in southern Ethiopia. A total of 425 children under 5 years of age were observed for 8 months. In general, malnourished children had a significantly higher incidence of diarrhoeal disease, even after controlling for possible confounding social, economic, and environmental effects, as well as for past history of illness. However, the extent of this association between nutritional state and morbidity differed between the two study populations. Thus, only wasting was associated with increased incidence of diarrhoeal disease among the pastoralist, whereas wasting, stunting, low weight for age, and low arm circumference all showed such an association in the agricultural community. Demographic and socio-economic characteristics as well as differences in the prevalence of stunting may explain this discrepancy.

Anthropometry↗
PubMed1992

The 5-HT1A antagonist (-)-alprenolol fails to modify sleep or zimeldine-induced sleep-waking effects in rats.

Sleep and waking in rats were studied for 8 h following administration of a selective 5-hydroxytryptamine (5-HT) reuptake inhibitor (zimeldine), a putative 5-HT1A antagonist (L(-)-alprenolol hydrogene tartrate monohydrate [(-)-alprenolol]) and a combination of (-)-alprenolol and zimeldine. Consistent with earlier findings, zimeldine gave a biphasic effect on sleep and waking. Waking was increased during the first 3 h, followed by a small decrease. Deep slow-wave sleep (SWS-2) showed the opposite trend. An initial decrease in SWS-2 was followed by an increase after around 3 h. Rapid eye movement sleep was markedly suppressed and latencies to sleep increased after zimeldine. (-)-Alprenolol had no effects on the different sleep and waking stages or latencies to sleep. The 5-HT1A antagonist also failed to modify the effects of zimeldine administration. The behavioral syndrome induced by a selective 5-HT1A agonist [8-hydroxy-2-(di-n-propyl-amino)-tetralin (8-OH-DPAT)] was clearly antagonized by administration of (-)-alprenolol, indicating that (-)-alprenolol was an efficient 5-HT1A blocker. The data indicate that the sleep-waking effects of zimeldine cannot easily be explained by stimulation of 5-HT1A receptors.

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMed1992

Studies on sleep/wake effects of serotonin reuptake inhibitors and receptor subtype involvement.

Studies with the serotonin uptake inhibitors zimeldine and alaproclate show biphasic effects on the sleep/wake axis in rats and cats. Zimeldine induced an initial waking response succeeded by a small SWS-2 increase in rats. The waking increase was not blocked by the 5-HT2 antagonist ritanserin nor by the putative 5-HT1A antagonist (-)-alprenolol. In cats, zimeldine induced initial behavioural changes which were succeeded by a large SWS-2 increase. Alaproclate gave similar initial responses as zimeldine in both species, and was succeeded by a moderate sleep increase in cats but not in rats. The complex sleep/wake effects following the serotonin uptake inhibitors may result from simultaneous induction of incompatible serotonergic effects.

Journal Article↗
PubMed1992

DNA fingerprinting in the epidemiology of African serogroup A Neisseria meningitidis.

The restriction endonuclease (RE) technique was used to compare 172 meningococcal group A strains collected between 1969 and 1990, mainly from countries of the so-called African Meningitis Belt, the Gambia and Ethiopia. The 64 strains from various African countries (Niger, Chad, Burkina Faso, Cameroon, Morocco, Djibouti) were distributed within 3 main restriction enzyme patterns (REPs); the 77 Gambian strains fell into 5 REPs and the 24 Ethiopian strains into 2 such patterns. Several of the main REPs were formed by clusters of closely related clones. Clones, very similar to dominating REPs of the 1960s in Niger, Burkina Faso and Cameroon, were in the 1980s found to be strongly represented in the Gambia to the extreme west of the Meningitis Belt. One of the Gambian clones from 1983-86 was identical to an Indian clone recovered in New Delhi 1986-87. Another clone was detected in 1983 in the Gambia, in 1989 again in the Gambia as well as in Ethiopia, and in 1990 in Tanzania. Our results are largely in line with those of previous studies based on modern techniques of protein and isoenzyme electrophoresis. The RE method is useful mainly for the exact genotypic differentiation of closely related clones, and seems to be a valuable complement to phenotypic tools for epidemiological mapping of Group A meningococcal infection.

Africa↗
PubMed1992

Child health in arid areas of Ethiopia: longitudinal study of the morbidity in infectious diseases.

We describe the incidence of some childhood infections in drought prone areas of southern Ethiopia. Our results are based on 24 months' biweekly observations of 828 children aged 0-5 years in the pastoralist community of Dubluk and the agricultural community of Elka. An average of 23% of the children in Dubluk and 13% in Elka were sick during any 2-week period. Diarrhoeal diseases represented the main cause of morbidity, but the yearly number of diarrhoeal episodes were lower than previously reported from Ethiopia. Respiratory tract infections and to a lesser extent diarrhoeal diseases, showed highest incidence rates during the main dry season. The highest incidence of lower respiratory tract infections coincided with an outbreak of measles. In Dubluk, children who lived near to the wells had higher incidence rates than those who lived further away, probably reflecting the importance of crowding on transmission rates. In Elka, literacy of mothers was associated with reduced incidence of both diarrhoeal and respiratory tract infections, whereas the use of open pit latrines was associated with increased diarrhoeal incidence. The decline in disease incidence in this region during the last months of our study may reflect an improvement of nutritional status.

Child, Preschool↗
PubMed1991

[Imported health problems].

International mass travel poses a challenge to our knowledge about health problems outside the Western World. Although infections dominate among imported diseases, the risk of contracting such illness is often exaggerated. Hence, medical examination of subjectively healthy persons after travelling abroad is rarely warranted, but should be offered adopted children and refugees from developing countries. Among the imported diseases, malaria, typhoid and tuberculosis should always be considered in cases of fever. Other commonly imported diseases include gastroenteritis, hepatitis, infections of skin and soft tissues, and sexually transmitted infections. Reference is made to some courses offering further education in the field of imported health problems.

Africa↗
PubMed1991

Presence of cfaD-homologous sequences and expression of coli surface antigen 4 on enterotoxigenic Escherichia coli; relevance for diagnostic procedures.

We examined the ability of a colonization factor antigen I (CFA/I) polynucleotide probe to identify coli-surface antigen 4 producing (CS4+) strains of enterotoxigenic Escherichia coli (ETEC). At low stringency (LS) the probe hybridized to colony lysates of strains previously shown to produce CS4 or CFA/I fimbriae. Only DNA from CFA/I+ strains maintained a stable probe-target hybrid under high stringency (HS) conditions. On examination of several clones from three previous CS4 producers, identified as positive in LS and negative in HS colony hybridization, spontaneous loss of nucleotide sequences homologous to a gene encoding a positive CFA/I regulator, CfaD, was found to be associated with lacking expression of CS4. Our findings indicate that, on stored or subcultured isolates of ETEC, identification of CS4 strains may benefit from applying gene probe technology.

Antigens, Bacterial↗
PubMed1991

Immunoprecipitation studies with biotinylated Entamoeba histolytica antigens.

The biotinylation of protein antigens for use in immunoprecipitation studies with parasite antigens is described. This technique was standardized to produce maximal labelling without compromising either the viability of the parasite or the antigenicity of labelled proteins. Live axenic Entamoeba histolytica trophozoites were optimally labelled by incubation of 10(7) parasites in 1 ml phosphate-buffered saline for 20 min at 37 degrees C with a final concentration of 10 mM N-hydroxy succinimido-biotin (NHS-B). Examination of antigens recognized by immunoglobulin from convalescent amoebic liver abscess patients and precipitated by protein A-Sepharose showed a general increase in immune response to amoebic antigens with time following treatment. Mass ratio mol. wts of immunoprecipitated antigens concur with those presented by other authors using alternate technology, in addition to recognizing antigens previously not identified by human sera. We therefore recommend biotinylation as a viable alternative to radiolabelling techniques for the study of parasite antigens and the humoral immune responses raised against them.

Animals↗
PubMed1991

[Exchange transfusion in cases of falciparum malaria].

Malaria is diagnosed in 50-70 patients each year in Norway. Severe malarial infection with cerebral involvement as well as hypoglycaemia, circulatory collapse and renal failure is often difficult to diagnose since the condition is only rarely seen in Scandinavia. This report describes a 49 year old seaman, who was admitted to hospital with a clinical picture of sepsis with multiorgan involvement including cerebral affection. Subsequently, it turned out that the patient had a severe infection with Plasmodium falciparum, involving more than 50 per cent of the red blood cells. Despite being comatose for one week with repeated attacks of grand mal type, and requiring 11 days mechanical ventilation plus dialysis for 4 weeks, he recovered uneventfully and was dismissed from hospital with only minor neurological sequelae. Even severe malaria with cerebral involvement can result in full restitution if the diagnosis is made early and exchange transfusion plus treatment with relevant drugs are instituted promptly.

Animals↗
PubMed1990

Effects of zimeldine, a selective 5-HT reuptake inhibitor, combined with ritanserin, a selective 5-HT2 antagonist, on waking and sleep stages in rats.

Sleep and waking in rats were studied 8 h following administration of a selective 5-hydroxytryptamine (5-HT) reuptake inhibitor (zimeldine), a selective 5-HT2 antagonist (ritanserin) and a combination of ritanserin and zimeldine. Consistent with earlier findings, zimeldine gave a biphasic effect on sleep and waking. Waking was increased the first 3 h, followed by an increase in deep slow wave sleep (SWS-2), maximal in hours 4 and 5. Ritanserin gave an increase in SWS-2 that was spread out over the recording period. Ritanserin + zimeldine also gave a biphasic effect as zimeldine did, and the initial increase in waking and the following increase in SWS-2 tended to be stronger. Thus, ritanserin did not block the initial waking effect seen after zimeldine administration, indicating that this waking effect was not due to 5-HT2 stimulation. The increase in SWS-2 seemed to reflect an addition of the increases following the zimeldine and ritanserin alone conditions. This suggests that the increase in SWS-2 seen after 5-HT reuptake inhibition and 5-HT2 blockade are independent phenomena. Zimeldine alone, ritanserin alone and the combination all gave a clear reduction of rapid eye movement sleep.

Animals↗
PubMed1990

[Kala-azar].

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Humans↗
PubMed1990

Detection of colonization factor antigen I-positive enterotoxigenic Escherichia coli with a cloned polynucleotide probe.

We compared a new colony hybridization assay with an established enzyme-linked immunosorbent assay for detection of enterotoxigenic Escherichia coli (ETEC) expressing colonization factor antigen I (CFA/I). The tests were applied to 135 human ETEC strains. Of these isolates, 30 had previously been characterized for CFAs. A strain harboring the plasmid vector of the polynucleotide gene probe, nine non-ETEC strains from healthy infants, and eight ETEC strains of animal origin were included for further evaluation of probe specificity. The two assays showed a high level of concordance in the specific detection of ETEC strains expressing CFA/I. A total of 24 strains tested positive in the CFA/I hybridization assay, while 23 of those strains were positive in the CFA/I enzyme-linked immunosorbent assay. The single discrepant result could be explained by the loss of a regulatory gene. The strain harboring the plasmid vector of the probe, the non-ETEC E. coli strains, and the ETEC strains of animal origin were all negative in the CFA/I probe assay.

Animals↗
PubMed1990

Characteristics of serogroup A Neisseria meningitidis responsible for an epidemic in Ethiopia, 1988-89.

In September 1988, an epidemic of meningococcal disease started in Ethiopia. 21 Neisseria meningitidis isolates recovered from patients in Addis Ababa and towns 200 km south of the capital were characterized by serogrouping, serotyping, testing of susceptibility to antibiotics, restriction endonuclease fingerprinting, and multilocus enzyme electrophoresis. The 21 isolates were essentially homogeneous for all properties tested and belonged to clone III-1 of serogroup A N. meningitidis, which was also responsible for the epidemics in Saudi Arabia in 1987 and in Sudan and Chad in 1988.

Adolescent↗
PubMed1989

Increased waking as well as increased synchronization following administration of selective 5-HT uptake inhibitors to rats.

Sleep and waking stages and EEG power spectra were investigated in rats following saline injections and injection of 10 and 20 mg/kg zimeldine or 10 and 20 mg/kg alaproclate, both selective 5-HT reuptake inhibitors. Following zimeldine there was a biphasic effect on sleep and waking, waking being increased during the first 2 1/2 h of recording, while slow wave sleep (SWS), in particular highly synchronized SWS-2 with high slow wave activity, was increased during the second 2 1/2 h recording period. Analysis of EEG power spectra indicated that the amount of synchronized slow wave activity was also increased within the sleep that occurred during the waking-dominated initial 2 1/2 h period. These data suggest simultaneous appearance of increased waking and increased synchronization following general serotonergic stimulation. They are interpreted as due to effects on different regions of the serotonergic system or on different serotonergic receptors. Consistent with earlier findings, zimeldine also suppressed rapid eye movement (REM) sleep. Following alaproclate, a clear waking effect was present, but only a weak synchronizing effect was seen. This is consistent with data on regional differences in uptake inhibition for zimeldine and alaproclate. Alaproclate also reduced REM sleep. Zimeldine or alaproclate was also administered to rats that had reduced sleep following pretreatment with a moderate dose of parachlorophenylalanine (PCPA). None of the drugs increased waking any further, but the PCPA-pretreated animals that received zimeldine had increased SWS-2, indicating that the SWS-2 increase following zimeldine alone was not a rebound effect.

Alanine↗