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Biomedical subjects

I Berg

Publications and source records attributed to I Berg.

At least 19 recordsLinked to original sources
PubMed1995

Effect of heavy metal ions on the release of reactive oxygen intermediates by bovine alveolar macrophages.

Short-term incubations of bovine alveolar macrophages (BAM) with metal-containing dusts induce the release of reactive oxygen intermediates (ROI). Incubations of BAM (90 min) with dissolved metal compounds (0.1-100 microM) combined with quartz dusts were performed to investigate the effects of single elements on BAM stimulation. As(III), as well as the calcium antagonists, Ni(II) and Ce(III), inhibited the secretion of superoxide anions (O2-) and hydrogen peroxide (H2O2). O2- concentrations were lowered by Mn(II) and Fe(II). Increased ROI concentrations were observed with V(IV) (O2- and H2O2) and Fe(III) (O2-). The addition of Cd(II), Cr(III) and V(V) showed no effect on the dust-induced respiratory burst. The influence of insoluble heavy metal compounds on ROI secretion by BAM were studied with metal oxide-coated silica particles. In most cases the release of ROI was not affected by the chemical modification of the particle surface. Coating with CuO markedly lowered the concentrations of O2- and H2O2, whereas vanadium(IV) oxide considerably increased both ROIs. Although most of the investigated metal compounds did not alter ROI secretion our present results with V(IV) and Fe(III) confirm our recent statistical evaluation of the effects of heavy metal-containing dusts on ROI secretion (Berg et al., 1993, J. Toxicol. Environ. Health 39, 341).

Animals↗
PubMed1995

Assessment of rehabilitation technologies in stroke. Outcomes and costs.

Initial functional ability (Barthel Index, mean 57) was found to be an important predictor of functional ability 1 year after stroke (mean 80) and for costs during the period. On average the total cost for a stroke patient was about SEK 200,000; the main expense, accommodation, averaged about SEK 140,000, while assistive devices amounted to SEK 2,600. Those who use assistive devices, although having achieved a high functional ability, perceive and rate their life situation (Nottingham Health Profile) considerably more impaired than those without assistive devices.

Aged↗
PubMed1992

Absence from school and mental health.

Severe school attendance problems, which once commanded a great deal of attention in child and adolescent psychiatry, have fallen from favour and are increasingly viewed as varieties of social impairment which may accompany disorders such as anxiety disturbances in the case of school refusal and conduct disturbances in the case of truancy. It is argued that this relegation of school attendance difficulties may have gone too far. As presenting complaints, albeit sometimes masked by apparent physical illness, they still have much to recommend them as indicators of a wide variety of present and future problems: educational, social, family, legal, medical, and, last but not least, psychiatric. Prevalence, features, causative factors, outcome, and management are discussed. Particular attention is paid to DSM and ICD classification. Gaps in present knowledge are indicated.

Absenteeism↗
PubMed1992

Identification and characterization of insulin-like growth factor receptors on adult rat cardiac myocytes: linkage to inositol 1,4,5-trisphosphate formation.

Cultured cardiac myocytes from adult Sprague-Dawley rats express both insulin-like growth factor-I (IGF-I) receptors and insulin-like growth factor-II/mannose 6-phosphate (IGF-II/Man6P) receptors and respond to IGF-I with a dose-dependent accumulation of inositol 1,4,5-trisphosphate [Ins(1,4,5)P3] and inositol 1,4-bisphosphate [Ins(1,4)P2]. Specific binding of [125I]IGF-I to isolated membranes from cultured cardiac myocytes amounted to 1-1.2%. Binding of [125I]IGF-I was inhibited by unlabeled IGF-I at nanomolar concentrations and insulin at much higher concentrations. These data suggest that IGF-I binds to its own receptor on rat cardiac myocytes. Competitive binding studies using isolated membranes from cardiac myocytes and [125I]IGF-II showed 2-4% specific binding. Binding of [125I]IGF-II was inhibited by IGF-II and much less potently by IGF-I and insulin. Immunoglobulin G (IgG) 3637 (an IgG directed against the IGF-II/Man6P receptor) partially inhibited binding of [125I]IGF-II whereas nonimmune IgG did not. Affinity cross-linking studies with [125I]IGF-II and cardiac myocyte membranes and subsequent analysis of the ligand-receptor complex using SDS-PAGE and autoradiography showed a radiolabeled band of approximately 250 kilodalton (kDa). The formation of the [125I]IGF-II-receptor complex was inhibited by incubation with IGF-II and IgG 3637 but not by insulin or nonimmune IgG. Western blotting of protein extracts from cultured cardiac myocytes was performed using IgG 3637 and an immunoperoxidase technique for the visualization of the IGF-II/Man6P receptor protein. A specific band at 220 kDa under nonreducing conditions was detected on the blots, providing further evidence for the expression of the IGF-II/Man6P receptor by cardiac myocytes. The effect of IGFs on the accumulation of inositol phosphates was measured by HPLC analysis of perchloric acid extracts from myo-[3H]inositol-labeled cultured cardiac myocytes. IGF-I (50 ng/ml) stimulated the accumulation both of Ins(1,4,5)P3 and Ins(1,4)P2 after 30 sec by 43% and 63%. IGF-II (up to 500 ng/ml) had no significant effect on inositol phosphate accumulation under the same conditions. However, in the presence of millimolar concentrations of Man6P, IGF-II (500 ng/ml) also increased Ins(1,4,5)P3 accumulation by 59%. We conclude that cardiac myocytes from adult rats express IGF receptors and respond to IGFs with the accumulation of Ins(1,4,5)P3 and Ins(1,4)P2. This effect seems to be mediated by an IGF-I receptor-specific pathway.

Animals↗
PubMed1991

Inhibition of alpha 1-adrenoceptor-mediated inositol phosphate accumulation in cultured cardiac myocytes by cyclic AMP-generating compounds.

Exclusive stimulation of the alpha 1-adrenoceptor in cultured cardiac myocytes led to a time-dependent increase of multiple inositol phosphate isomers. However, under physiological conditions, alpha 1-adrenergic stimulation is accompanied by beta-adrenergic stimulation as noradrenaline is a ligand for both receptors. Thus, the aim of our study was to investigate the cross-talk between the alpha 1- and the beta-adrenoceptor on the post-receptor level. When both the alpha 1- and the beta-adrenoceptor were stimulated with noradrenaline for 30 s, a diminished increase in all inositol phosphates and a concomitant increase in cAMP was observed. Similar results were obtained by pre-incubation of the myocytes with forskolin for 2 min and subsequent stimulation of the alpha 1-adrenoceptor for 30 s. In contrast, after 15 min the inhibitory effect of simultaneous beta-stimulation as well as of forskolin pre-treatment upon the alpha 1-mediated inositol phosphate response was abolished, although the concentration of cAMP was still elevated. These data suggest that beta-adrenoceptor- and forskolin-induced cAMP production or a cAMP-activated subsequent signal have a short-term, transient, inhibitory effect on alpha 1-adrenoceptor-mediated inositol phosphate response.

Adrenergic alpha-Antagonists↗
PubMed1990

Effect on cooking time on mutagen formation in smoke, crust and pan residue from pan-broiled pork.

The effect of cooking time on mutagenic activity in crust, pan residue and smoke from pan-broiled pork patties was studied in the Ames Salmonella mutagenicity test system. The effect on mutagenicity of reheating the cooked patties and of keeping them warm was also studied. The meat was broiled at 200 degrees C for various times between 2 and 10 min. Broiled meat was reheated up to 5 times at 200 degrees C, each time to a centre temperature of 70 degrees C. Reheating was also performed in a microwave oven for 2 min and in an electric oven at 200 degrees C for 10 min. In addition, broiled patties were kept warm at 60 degrees C in an incubator for up to 9 hr. The mutagenic activity increased rapidly in all fractions except the volatile phase over the first 6 min of cooking, after which time only a slight increase was seen. At cooking times below 4 min no mutagenic activity was detected in the smoke. Reheating or keeping the meat warm for up to 9 hr had very little effect on the mutagenic activity of the meat. Reversed-phase high-performance liquid chromatography mutagenicity profiles of the aerosol, crust and pan-residue extracts showed no major qualitative differences in samples cooked at different times. It is concluded that during pan broiling at 200 degrees C the major part of the mutagenic activity is formed during the first 6 min of cooking. Reheating the meat or keeping it warm does not significantly affect the mutagenic activity. No major additional mutagens are formed during continued heating for up to 25 min.

Animals↗
PubMed1990

The identification of psychiatric disorders in children who fail to attend school: a cluster analysis of a non-clinical population.

Interviews were conducted with parents of 100 children taken to a 'school attendance committee', because of persistent failure to attend school. Clinical assessment of the attendance problem was carried out so that children were categorized as 'school refusers' (N = 24), 'truants' (N = 53), 'both refusers and truants' (N = 9), or as 'neither' (N = 14). Any ICD-9 psychiatric disorder was separately identified. Cluster analysis of information collected in a standard way indicated that there was a group of children with the features of 'school refusal' who often had generalized neurotic disorders as well and who were mostly girls, another group with the features of 'truancy' all of whom had conduct disorders who were mainly boys, and a third cluster of children who were usually 'truants' but less often psychiatrically disturbed. The study provided evidence for the existence of school refusal with and without generalized neurotic disturbance in a non-clinical population.

Absenteeism↗
PubMed1990

Chemistry and biological activity of volatile and nonvolatile mutagenic compounds from cooked food.

Cooking fumes constitute a major part of the mutagenic activity detected in indoor air samples. The chemical nature of the smoke mutagens has not been determined, but existing data indicate the presence of carcinogenic heterocyclic amines, previously identified in crust and pan residue from fried meat. Reports on the chemical nature and biological activity of these compounds are reviewed.

Animals↗
PubMed1989

Metabolism of inositol phosphates in alpha 1-adrenoceptor-stimulated and homogenized cardiac myocytes of adult rats.

Previous studies demonstrated the accumulation of inositol mono- and poly-phosphates in carbamoylcholine-stimulated cultured cardiac ventricular myocytes of adult rats [Berg, Guse & Gercken (1989) Biochim. Biophys. Acta 1010, 100-107]. Stimulation with noradrenaline (50 microM) in the presence of propranolol (10 microM) led to a time-dependent pattern of inositol mono- and poly-phosphates in cultured cardiac-ventricular myocytes. Ins(1,4,5)P3 and Ins(1,3,4,5)P4 increased in a rapid initial phase. The degradation products of Ins(1,4,5)P3, namely Ins(1,4)P2 and Ins(4)P, accumulated between 1 and 15 min. Ins(1,3,4,5)P4 was rapidly dephosphorylated to Ins(1,3,4)P3, which was then metabolized to Ins(1,3)P2 and Ins(3,4)P2. The last two InsP2 isomers and their degradation products, Ins(1)P and Ins(3)P (determined as an enantiomeric mixture), increased at extended stimulation periods. To confirm the pathway of Ins(1,3,4,5)P4 degradation, homogenates of isolated ventricular myocytes were incubated with [3H]INs(1,3,4,5)P4. The subsequent products were Ins(1,3,4)P3, Ins(3,4)P2, Ins(1,3)P2 and InsP. The effect of noradrenaline was antagonized by prazosin (0.1 microM), but not by yohimbine (0.1 microM), indicating phosphoinositidase activation via the alpha 1-adrenoceptor.

Animals↗
PubMed1989

Carbamoylcholine-induced accumulation of inositol mono-, bis-, tris- and tetrakisphosphates in isolated cardiac myocytes from adult rats.

The effect of carbamoylcholine on the phosphoinositide cycle in isolated ventricular myocytes from adult rats was studied. Separation of the phosphoinositides by high-performance thin-layer chromatography showed a constant ratio of incorporation of myo-[2-3H]inositol into phosphatidylinositol, phosphatidylinositol 4-monophosphate and phosphatidylinositol 4,5-bisphosphate of cultured cardiac myocytes after at least 2 h. Carbamoylcholine caused a dose-dependent and time-dependent accumulation of inositol mono-, bis- and trisphosphates, which was antagonized by atropine. Using anion-exchange HPLC the existence of inositol 1,4,5-trisphosphate, inositol 1,3,4-triphosphate and inositol 1,3,4,5-tetrakisphosphate was confirmed in rat ventricular myocytes. Inositol 1,4,5-trisphosphate and inositol 1,3,4,5-tetrakisphosphate accumulated within 20 s, while inositol 1,3,4-trisphosphate, inositol 1,4-bisphosphate and inositol monophosphate increased within 5 min.

Animals↗
PubMed1989

Influence of creatine, amino acids and water on the formation of the mutagenic heterocyclic amines found in cooked meat.

Creatine or one of 15 amino acids were mixed with minced pork before broiling at 200 degrees C. Total mutagenic activity and reversed-phase HPLC-separated mutagenicity profiles were determined for the crust and pan residue of all samples and also in the aerosol fraction of the smoke formed during cooking of the creatine-fortified samples. Addition of 5% (w/w) creatine increased the total mutagenicity 4-fold without changing the mutagenicity profile of either crust, pan residue or aerosol. Amino acid addition (1% w/w) increased the total mutagenicity between 1.5 (lysine) and 43 times (threonine). In most cases the mutagenicity profiles of crust and pan residues were changed by amino acid addition. Dry-heated mixtures of amino acids and creatine were all mutagenic with a 250-fold range between the amino acids. The production of known food mutagens in these mixtures was analyzed by LC-MS of HPLC-fractionated mutagenic peaks. Serine, threonine, phenylalanine, alanine, leucine and tyrosine were all shown to give rise to one of the known food mutagens 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx), 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) or 2-amino-trimethylimidazopyridine (TMIP). Lyophilized and subsequently fried meat patties and a heated powder of lyophilized meat juice were both mutagenic, with mutagenicity profiles similar to the regular meat crust, showing that water is not a prerequisite for mutagen formation in meat. MeIQx, 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline (4,8-di-MeIQx) and PhIP were shown, by LC-MS, to be present in the dry-heated meat juice. It is concluded that creatine and free amino acids are the main reactants of the mutagen-forming reactions that occur during frying of meat. Creatine is probably a necessary part of all of these reactions; what specific compounds are formed in each case therefore depends upon the levels in the meat of certain free amino acids and their interactions with other, as yet unknown, compounds in the meat.

Amines↗
PubMed1989

Sleep EEG evaluation: a comparison of results obtained by visual scoring and automatic analysis with the Oxford sleep stager.

Oxford Medical has introduced an automatic sleep stager based on the stage-scoring criteria by Rechtschaffen and Kales. With our study we intended to examine whether the results of the stager (version 3.0) match those of the visual evaluation by two independent raters. We also wanted to test the reliability of this automatic sleep stage-scoring system. Ten somnopolygrams of subjects without sleep disturbances served as a basis for the comparison. Each sleep recording was scored twice automatically by the stager, twice visually by the first rater, and once by the second rater. The two automatic analyses of the somnopolygrams differed by 4.3% in a total of 13,850 epochs (1 epoch delta 20 s) regarding sleep stage scoring. The difference between the first and the second visual evaluation by the same rater amounted to 5.7%, whereas the results of the two independent raters deviated by 8.7%. Compared with the results of the visual analysis reached as a consensus by both raters--the so-called optimized visual analysis--the stager showed a 26.9% difference. The automatic analysis scored fewer epochs as stages wake, rapid eye movement (REM), and 2 and more as stages 1, 3, and 4. The sleep stager's frequent difficulty in identifying stage wake correctly as well as its incorrect allocation to other stages--mainly stage REM--could lead to misinterpretations of sleep recordings, whereas the increase in stages 1, 3, and 4, as compared with visual scoring, was negligible.

Adult↗
PubMed1987

Successful management of daytime enuresis using alarm procedures: a randomly controlled trial.

Forty four children with daytime wetting were included in a randomly controlled trial of two alarm devices, a contingent one that sounded when wetting occurred and a non-contingent one that went off from time to time unrelated to wetting events. A quota allocation system ensured comparability between treatment groups. Two thirds responded to an alarm by becoming dry. The non-contingent alarm produced as good a response as the contingent one and is recommended for routine use in children with diurnal enuresis. Twenty three per cent of those who responded to treatment relapsed up to two years after completion of the trial.

Adolescent↗
PubMed1985

Classification of severe school attendance problems.

Sixty-four children taken to court for failure to attend school were reliably classified into 4 groups, according to whether they exhibited the features of 'school refusal' and/or 'truancy'. About a fifth of them were found to exhibit 'school refusal'; a third showed 'truancy'; less than a sixth exhibited both 'school refusal' and 'truancy' combined; and over a third had the characteristics of neither condition. Differences between these categories were found in manifestations of psychiatric disturbance and in responsiveness to a court adjournment procedure.

Absenteeism↗
PubMed1985

A color-contingent prism displacement aftereffect.

Observers were trained to point with feedback to red and blue dots whose images had been laterally displaced in opposite directions by a reversible prism. On pretraining and posttraining trials the red and blue dots were aligned vertically in the absence of visual orientation cues. The alignment was modified by the pointing training on the posttraining trials. The colors were aligned in the direction of their prior prismatic displacement. One control experiment showed that the alignment aftereffect requires feedback during the pointing task. Another experiment in which observers pointed to the red and blue dots with opposite arms showed that pointing to both dots with the same arm was necessary to produce the alignment aftereffect. Changes in the perceived position of objects in the visual field occur when changes in perceived limb position cannot compensate for a sensorimotor conflict. Eye torsion or fixation displacements are proposed as alternative mechanisms mediating the aftereffect.

Adaptation, Physiological↗