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Biomedical subjects

S Sandberg

Publications and source records attributed to S Sandberg.

At least 109 records · Page 6Linked to original sources
PubMed1987

Porphyrin-induced photodamage to isolated epidermal cells from hairless mice.

UVA light photodamages epidermal cells, as measured by inhibition of enzymatic activity and inhibition of respiration. This photodamage is greatly augmented in the presence of protoporphyrin as a photosensitizer. The increase in photodamage is greater for the cytosolic and mitochondrial enzymes lactate dehydrogenase and glutamate dehydrogenase and least for the lysosomal enzymes beta-glucuroninidase and N-acetyl-beta-glucosaminidase. Upon irradiation in the presence of protoporphyrin, N-acetyl-beta-glucosaminidase is released from the epidermal cells. These results may help to explain some features of the pathogenesis of erythropoietic protoporphyria.

Animals↗
PubMed1986

Phototoxicity of tetracyclines as related to singlet oxygen production and uptake by polymorphonuclear leukocytes.

The photo-induced singlet oxygen production of six tetracyclines was measured as tryptophan degradation. Demethylchlortetracycline was the most efficient singlet oxygen producer followed by doxycycline. The least efficient producer was minocycline. Doxycycline, however, was the most potent inducer of photodamage to polymorphonuclear leukocytes (PMNLs) followed by demethylchlortetracycline. Accordingly, the singlet oxygen production during irradiation did not correlate with the induction of photodamage to the PMNLs. However, the uptake of doxycycline by the cells was 3 times higher than that of demethylchlortetracycline, and the tetracycline-induced photodamage to the PMNLs correlated with the product of singlet oxygen production during irradiation and the drug uptake by the cells.

Free Radicals↗
PubMed1986

Factors important for the measurement of chemiluminescence production by polymorphonuclear leukocytes.

Chemiluminescence (CL) production by phagocytosing polymorphonuclear leukocytes (PMNLs) was measured by an automatic photoluminometer with built-in mixing and temperature controls. Agitation of the vials with PMNLs and opsonized zymosan particles influenced both the lag time and the CL production. Maximal production was obtained by continuous mixing of the samples, the reaction peak occurring within 6 min. Increasing the temperature from 20 to 40 degrees C also increased the CL production, and in further experiments 37 degrees C was used. Aggregation of the PMNLs was avoided by washing the cells in PBS containing gelatin 1 g/l. Glucose, Ca2+ and Mg2+ in the final reaction mixture were necessary for maximal CL responses. The measurements of CL per s up to 4 min, the peak CL value, or the integral below the CL curve up to 6 min were all linearly proportional to the number of PMNLs in the reaction mixture. Since the lag time and the time before reaching peak CL may vary, the integral below the curve up to 6 min was chosen as the mode of CL measurement. On repeated measurements the coefficient of variation was 6.3%. The mean CL integral value for PMNLs from 14 healthy individuals was 205 +/- 19 mVs, indicating a good reproducibility of the standardized assay.

ABO Blood-Group System↗
PubMed1986

Agreement between teachers' ratings and observations of hyperactivity, inattentiveness, and defiance.

The relationship of directly observed classroom behavior and teacher ratings on questionnaires with a judgemental (Conners Teacher Rating Scale) or operational format was examined for 33 boys aged 6 years 5 months to 7 years 7 months. Results showed a high degree of association between observed and rated behavior. This association did not vary with the format of the rating scales but did vary with the nature of the behavior being rated. Defiance was more reliably rated than hyperactivity or inattentiveness. Several behaviors exerted a halo effect on ratings of hyperactivity, inattentiveness, and behavior problems. In particular, defiance toward a teacher increased the likelihood that a child would be rated as hyperactive or inattentive regardless of his observed level of activity or attentiveness. These results support the validity of behavior rating scales as screening measures for hyperactivity, inattentiveness, and defiance and indicate that a child's defiance and disobedience are significant causes of misclassification.

Attention↗
PubMed1986

Influence of tetracyclines and light on the release of lysozyme from human granulocytes and monocytes.

Doxycycline inhibited the release of lysozyme from human granulocytes and monocytes exposed to non-opsonized zymosan particles. This effect was more marked for granulocytes than for monocytes. Oxytetracycline, however, did not influence the release. The difference between the drugs can be explained by differences in their lipid solubilities. The divalent cation chelator, EDTA, also reduced the release of lysozyme from leukocytes exposed to non-opsonized zymosan. Accordingly, the selective release of lysozyme from human leukocytes is divalent cation dependent. The inhibition of release by doxycycline is most likely also due to binding of these ions. When the cells were exposed to UVA light in the presence of doxycycline, the inhibition of lysozyme release was potentiated. Using irradiated cells, maximal inhibition was obtained at 20 micrograms doxycycline/ml. However, it is not clear whether these results have clinical relevance.

Doxycycline↗
PubMed1986

Stability of haematological constituents during simulated mail transport as measured by Coulter Counter S plus II or Technicon H 6000.

Stability of blood constituents after mail transport was examined using two different automated haematology instruments, that is, Coulter Counter S plus II and Technicon H 6000. The results were analysed by two different statistical methods. In all but four cases these methods yielded similar results. The B-LPC, B-EPC B-Hb, B-EVF, E-MCH, E-MCHC and B-TPC were stable after mail transport for 48 h when measured with Coulter Counter S plus II. In contrast, none of these parameters were stable when measured with Technicon H 6000. The differential count measured by cytochemical staining technique with Technicon H 6000 was stable for 72 h whereas the percentage of L-Lymphocytes measured with Coulter Counter S plus II was unstable after 24 h of mail transport. The criteria of stability are discussed in relation to changes of constituents that are of importance in medical decision making.

Autoanalysis↗
PubMed1985

Hyperactive disorder of childhood. Some clinical implications of recent research.

In many European countries hyperkinesis is a relatively rare clinical diagnosis compared with the United States. Though systematic international studies comparing the diagnostic process with regard to this disorder are still lacking, it is likely that the reasons for the vast differences in the rates of the disorder do not lie in the differences of the children's behaviour but in diagnostic practice. Individual components of hyperactivity, namely overactivity, restlessness and poor concentration are common among children attending clinics as well as in randomly selected samples in the general population. Treatment for hyperactivity is largely the same as for the majority of child psychiatric disorders which predominantly involve disturbances of conduct. As the 'causes', as well as the factors maintaining the symptoms, are often complex, one form of treatment is seldom adequate. In most cases a combination of psychological and educational treatments is necessary. Stimulant drugs, though in a few instances capable of producing instant and dramatic therapeutic effects, should not be used as a treatment of first choice.

Attention Deficit Disorder with Hyperactivity↗
PubMed1985

In vivo and in vitro effects of doxycycline on leucocyte membrane receptors.

Tetracyclines, particularly doxycycline, have adverse effects on granulocyte function in vitro. We have examined the effects of doxycycline on membrane receptors for IgG (Fc gamma-R) and C3b (C3b-R) on granulocytes and lymphocytes, as well as on the sheep erythrocyte receptor (E-R) on T lymphocytes. Acne patients given doxycycline orally had a lower percentage of Fc gamma-R positive granulocytes (57%) than before treatment (80%) or compared to healthy controls (81%). Following in vitro doxycycline incubation, normal granulocytes showed decreased levels of Fc gamma-R positive cells. This effect was counteracted by the addition of magnesium during incubation. The deleterious effect of doxycycline on granulocyte functions may be due to decreased levels of Fc gamma-R bearing granulocytes. Doxycycline in vivo or in vitro had no significant effect on the proportion of C3b-R bearing granulocytes or lymphocytes or the T lymphocyte percentage. After in vitro irradiation with light at 340-380 nm, however, both granulocytes and lymphocytes preincubated with doxycycline showed up to 50% decrease in Fc gamma-R bearing cells, while control cells without doxycycline were unaffected.

Acne Vulgaris↗
PubMed1985

Further psychodrama with delinquent adolescents.

It was postulated that an integration of behavioral-cognitive techniques within a psychodramatic group therapy framework would reduce delinquents' acting-out tendencies and improve ego strength. The population consisted of a control and an experimental group of adolescents aged 14 to 16 of both sexes that were adjudicated delinquent. There were ten adolescents in the control group and initially eleven adolescents in the experimental group (only seven completed the twelve ninety-minute sessions). Both pre- and posttest measures on the Jesness, the High School Personality Questionnaire, and the I-E Scale were administered to the two groups of subjects. The results showed that significant improvement occurred in the delinquents' asocial index (.01 level), ego strength (.05 level), and introversive tendencies (.01 level). This study demonstrated that behavioral contracting, monetary reinforcement, and alternative behavioral rehearsal can be effectively integrated with more traditional psychodramatic techniques to reduce delinquents' acting-out tendencies.

Adolescent↗
PubMed1984

Influence of pH on porphyrin production in Propionibacterium acnes.

Propionibacterium acnes was grown on Eagle's medium for 4-15 days at pH 5.3-7.2 The porphyrin production was measured both by direct fluorometry and by high pressure liquid chromatography (HPLC). The greatest concentration of porphyrins was produced at pH 6.1. Protoporphyrin was the dominant porphyrin species present in the bacteria in all samples. The relative amount of coproporphyrin was greatest at pH 6.7 after 4 days of incubation. In human skin there are local variations in the pH; therefore our findings may be of importance for porphyrin production in acne.

Chromatography, High Pressure Liquid↗
PubMed1984

Hyperactive behavior in English schoolchildren: a questionnaire survey.

The differences in apparent prevalence of childhood hyperactivity between England and North America are more than 20-fold. This paper seeks to illuminate the reasons for the difference by applying a standard measure [Conners Teacher Rating Scale] to 437 English schoolchildren, aged 6 to 9 years, and comparing them with published surveys from the United States and Australasia. The rating scale had moderate interrater reliability and stability over time; it distinguished between children referred for psychiatric treatment and normal schoolchildren. Component analysis yielded a factor of hyperactivity-inattentiveness, distinct from conduct disorder. The mean hyperactivity scores of English children were higher than in most U.S. surveys but lower than in New Zealand. The national differences in rates of diagnosed hyperactivity are likely to reflect diagnostic inconsistency rather than true differences in children's behavior.

Attention Deficit Disorder with Hyperactivity↗