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K Bergman

Publications and source records attributed to K Bergman.

At least 37 records · Page 2Linked to original sources
PubMed1991

Mutations in the two flagellin genes of Rhizobium meliloti.

The previously cloned DNA fragment which complements the behavioral defects of the che-1 and che-3 mutations of Rhizobium meliloti codes for two nearly identical (93%) flagellin genes. A wild-type copy of one of the two genes (flaA) but not the other (flaB) can complement the mutations. The behavior and flagellar morphology of newly isolated strains carrying insertion and deletion mutations or various combinations of these mutations demonstrated that either gene product alone can form functional flagellar filaments but when both gene products are present they interact in the formation of filaments. Both the nucleic acid sequences of the genes and the deduced amino acid sequences of the proteins from strain Rm1021 showed significant differences from the sequences determined previously for strain RU10406. (E. Pleier and R. Schmitt, J. Bacteriol. 171:1467-1475, 1989). The tandem arrangement of the two genes is stable, although in vitro recombination between them gave rise to a strain with wild-type behavior.

Amino Acid Sequence↗
PubMed1990

Effects of dietary sodium selenite supplementation on salicylate-induced embryo- and fetotoxicity in the rat.

The effects of dietary supplementation with sodium selenite (3.0 or 4.5 ppm Se) for 8 weeks prior to and throughout gestation on sodium salicylate induced embryo- and fetotoxicity (resorptions, fetal deaths, malformations, fetal weight reduction) have been studied in the rat. Salicylate was administered either as daily intragastric bolus doses of 250 mg/kg on gestation days 6-13 (maternal peak and trough salicylate levels of 222-120 micrograms/ml whole-blood) or via constant rate intravenous infusion of 150 mg/kg/day on the same gestation days via implanted osmotic minipumps (stable average maternal blood salicylate level of 120 micrograms/ml = human antirheumatic concentration). Both gavage and infusion of salicylate resulted in an increase of resorptions and fetal deaths as well as a decrease of fetal body weights. Gavage with salicylate also produced about 50% malformed fetuses. Selenite did not protect against the embryotoxic effects of salicylate administered as intragastric bolus doses. However, selenite was found to significantly increase fetal survival rate in the infusion experiment, although it did not counteract the decrease of fetal body weight. In animals fed selenite only, no negative effects on fetal body development were noted. The protective effect of selenite against salicylate induced embryotoxicity is difficult to explain, since very little is known about the mechanisms of salicylate embryotoxicity and the biological effects of selenium. However, an interaction between selenium, via glutathione peroxidase, and salicylate at the level of prostaglandin synthesis could be possible.

Animals↗
PubMed1990

Life events: the reliability of rating changes in routine and environment.

Alterations in routine and environment can affect clinical state in patients suffering from cognitive impairment. A method for rating life events for changes in routine and environment is described and found to be highly reliable even when used by inexperienced raters after brief training.

Activities of Daily Living↗
PubMed1990

Accumulation and turnover of metabolites of toluene and xylene in nasal mucosa and olfactory bulb in the mouse.

Autoradiography of male mice following inhalation of the radioactively labelled solvents, toluene, xylene, and styrene, revealed an accumulation of non-volatile metabolites in the nasal mucosa and olfactory bulb of the brain. Since no accumulation occurred after benzene inhalation, it was assumed that the activity represented aromatic acids, which are known metabolites of these solvents. This was supported by the finding that also radioactive benzoic acid (main metabolite of toluene) and salicylic acid accumulated in the olfactory bulb. High-performance liquid chromatography revealed that after toluene inhalation (for 1 hr), nasal mucosa and olfactory bulb contained mainly benzoic acid, with a strong accumulation in relation to blood plasma, and considerably less of its glycine conjugate, hippuric acid. After xylene inhalation, on the other hand, methyl hippuric acid dominated over the non-conjugated metabolite, toluic acid. The results indicate a specific, possibly axonal flow-mediated transport of aromatic acids from the nasal mucosa to the olfactory lobe of the brain. The toxicological significance of these results remains to be studied.

Animals↗
PubMed1990

PET imaging in obsessive compulsive disorder with and without depression.

Obsessive compulsive disorder (OCD) is a classic psychoneurosis which is frequently complicated by major depression. Recent positron emission tomography neuroimaging studies, when taken in the context of a variety of other data, implicate a brain dysfunction involving the orbital prefrontal cortex and the striatum in the mediation of OCD behaviors and those of the related Gilles de la Tourette's syndrome. The anterolateral prefrontal cortex is implicated in the secondary major depressions often complicating OCD.

Brain↗
PubMed1990

Thoracic vascular injuries: a post mortem study.

We reviewed the coroner's records for all pediatric (less than 16 years of age) trauma fatalities in Ontario (population, 9.5 million) for the period January 1, 1985, through December 31, 1987. Twenty-six (8%) of the 322 cases for which complete autopsy data were available had major thoracic vascular injuries. Twenty-five deaths occurred within 6 hours of injury. The majority of patients had at least one AIS 6 injury. The aorta was the most frequently injured vessel. Major thoracic vascular injuries are more common among children than previous reports suggest, probably because they are rapidly fatal. Many deaths occur in the field, at local hospitals, or in transit before the patient can reach a trauma center. Efforts to reduce the number of total thoracic vascular injuries should focus on primary and secondary prevention.

Adolescent↗
PubMed1988

Physiology of behavioral mutants of Rhizobium meliloti: evidence for a dual chemotaxis pathway.

Wild-type and nonchemotactic mutant strains of Rhizobium meliloti were tested for attraction to localized sites on alfalfa roots and for attraction to numerous small molecules, including sugars, amino acids, and two fractions derived from alfalfa root extracts. Four strains (carrying mutations che-6, che-11, che-12, and che-26) lost all responses and were classified as generally nonchemotactic mutants. One strain (carrying mutation che-7) lost responses to a group of structurally unrelated amino acids but retained all other responses and was classified as a putative sensory transducer mutant. Two strains (carrying mutations che-1 and che-3) lost responses to all the amino acids and sugars tested but retained normal responses to localized sites on roots and to the root fractions. These two mutant strains could not be classified according to the generally accepted model for a sensory pathway, derived from studies of enteric bacteria, and provided evidence for a dual chemotaxis pathway in R. meliloti.

Amino Acids↗
PubMed1988

Collective dose to the Swedish population from intraoral radiography.

In 1984 the Swedish National Institute of Radiation Protection (SSI) undertook an investigation (KAST) of 400 randomly selected dental offices to check the extent to which the new rules and recommendations concerning radiation protection (SSI 1978, 1980) were applied. Data for calculation of the energy imparted per bitewing examination of an adult were available. The information obtained was utilized for estimating the collective dose in Sweden from intraoral radiography. The mean value of the energy imparted from an ordinary bitewing examination was 0.48 mJ. The quotient between the sum of all imparted energy during 1984, 5,519 J, and the number of inhabitants in that year was 0.66 mJ. This corresponds to 1.5 ordinary bitewing examinations per individual in Sweden. The collective effective dose equivalent is 79 manSv after transformation from the total energy imparted. The average energy imparted from the annual natural irradiation in Sweden is 100 mJ, with variations between 35 and 350 mJ, giving totally to the population 830,000 J. The dose contribution from intraoral radiography is thus considered of minor importance when taking into account the variations of the natural irradiation as well as the benefit of the diagnostic gain in dentistry and the enhancement of public dental health.

Adult↗