Search PubMed⌕ Search

Biomedical subjects

B Johansson

Publications and source records attributed to B Johansson.

At least 883 records · Page 49Linked to original sources
PubMedDate not supplied

Nosocomial transmission of hepatitis C virus.

The nosocomial transmission of hepatitis C involving three subjects participating in a research project in a Swedish hospital is described. One person contracted acute hepatitis C and another participant had an asymptomatic seroconversion. A temporal relationship between participation in the experiments and seroconversion for hepatitis C, and virology with phylogenetic analyses, suggest that they most probably contracted hepatitis C from a third subject who unknowingly had chronic hepatitis C. Faulty nursing and procedural routines were identified as the probable cause of the transmission. Our findings reinforce the need for medical personnel to strictly adhere to universal precautions worked out to prevent the transmission of blood-borne viruses and underline the importance of a continuous supervision of nursing and procedural routines, even in hospitals with well-educated staff and presumably high standards.

Antibodies, Viral↗
PubMedDate not supplied

Age-related changes in immune parameters in a very old population of Swedish people: a longitudinal study.

This study used a longitudinal design to examine age-related changes in a well-defined sample of Swedish people ranging from 86 to 92 years of age at baseline. The longitudinal design encompassed three measurement occasions with 1 year intermeasurement intervals. The results were analyzed by multivariate analyses of variance (MANOVA), which is useful for comparing individuals over time. Healthy middle-aged subjects (39 years SD +/- 5.8) served as controls. The proliferative responses to Concanavalin A (Con A), a T-cell mitogen, indicated significant lower levels in responses of the old when the two groups were compared. The MANOVA revealed no significant change in mitogen responses over measurement occasions in the old sample as compared with the young. However, when cell types and lymphocyte subpopulations were examined, significant differences were found between the two age groups in many of these parameters and for some (lymphocyte percentages and numbers, CD3 numbers) the MANOVA indicated significant decreases over the measurement occasions in the very old. The results also consistently indicated significant intraindividual correlations in cell types, lymphocyte subpopulations, and mitogen responses over time.

Adult↗
PubMedDate not supplied

The short extracellular domain of the T cell receptor zeta chain is involved in assembly and signal transduction.

The zeta chain is required in the TCR complex to guarantee its surface expression and function. However, an understanding of the interaction(s) between the zeta chain and the other proteins in the TCR/CD3 has not yet been achieved. In this report, we attempt to assign a functional role to the short extracellular (EC) domain of the zeta chain by studying its unique positive charge, a lysine at position 9, because of its interesting location to the interchain disulphide bond of the zeta chain homodimer. We show that amino acid exchanges of lysine 9 to glycine, serine, cysteine or asparagine generate TCR complexes which are clearly defective in antigenic signalling. Interestingly, the non-conservative point mutations were segregating TCR complex signalling pathways. However, lysine 9 is not critical for TCR complex surface expression unless the positively charged lysine is exchanged for the negatively charged amino acid aspartic acid. The zeta chain mutant bearing a lysine to cysteine exchange is the sole mutant to be inefficiently co-precipitated with the TCR/CD3 complex suggesting a loose interaction of the zeta chain within the TCR complex.

Amino Acid Sequence↗
PubMedDate not supplied

Effects of atenolol, metroprolol, and pamatolol on cardiac and vascular beta-adrenoceptors in the rat.

Three beta-adrenoceptor antagonists--atenolol (A), metoprolol (M), and pamatolol (P)--were examined with respect to their effects on isoproterenol responses of isolated right atria and portal veins from rats. With all three blockers at concentrations of 10(-7), 10(-6), and 10(-5) M, the chronotropic atrial responses indicated a linear relation with slope of 1 for log (dose ratio - 1) versus log[blocker]. The following pA2 values were obtained: A = 7.14, M = 7.51, P = 7.56. Inhibition of spontaneous contractions in portal veins by isoproterenol was studied after alpha-adrenoceptor blockade by phenoxybenzamine. The beta-adrenoceptor antagonists were used at 10(-6), 10(-5), and 10(-4) M in these experiments. Only with P did the relation log (dose ratio-1) versus log[blocker] show a slope near unity, whereas A and M gave slopes significantly less than 1. Intercepts of the regression lines with the abscissa corresponded to pA2 values of A = 6.01, M = 6.51, P = 5.54. The results indicate that all three substances are "cardioselective" beta-adrenoceptor antagonists devoid of intrinsic beta-stimulatory action. A and M show a comparable degree of cardioselectivity, whereas P is more selective.

Adrenergic beta-Antagonists↗
PubMedDate not supplied

Effects of 17beta-estradiol and progesterone on transcription of human papillomavirus 16 E6/E7 oncogenes in CaSki and SiHa cell lines.

Several in vitro studies have addressed the interactions between estrogen/progesterone and human papillomavirus (HPV), but the results are controversial. We evaluated the effects of estrogen and progesterone and their antagonists on messenger RNA expression of HPV16 E6/E7 in HPV16-positive cell lines CaSki and SiHa with real-time reverse-transciptase polymerase chain reaction method. Colorimetric assay with tetrazolium salt (WST-1) and flow cytometry were used for testing proliferation and apoptosis. No statistically significant changes were found after hormone treatment in the expression of HPV16 E6/E7 or hormone receptors in CaSki and SiHa cell lines. Progesterone increased cell proliferation in both the cells, while estrogen increased proliferation of SiHa cells only. Estrogen seemed to protect the CaSki cells from apoptosis, and tamoxifen did not abrogate this effect. Progesterone slightly increased apoptosis of CaSki cells, and this effect was neutralized with RU486. In this study, estrogen and progesterone did not change either the transcription levels of HPV16 E6/E7 or estrogen receptor or progesterone receptor levels. Hormone receptor antagonists had no effect on transcription. Both hormones might have a permissive effect for the growth of cervical cancer, by promoting cell proliferation and making the cells vulnerable to mutations. In addition, estrogen acts as an antiapoptotic agent allowing growth advance of the cells infected with oncogenic HPV.

Apoptosis↗
PubMedDate not supplied

The influence of white matter lesions on neuropsychological functioning in demented and non-demented 85-year-olds.

White matter lesions on computed tomography of the head were studied in relation to neuropsychological functioning in subjects from a representative sample of non-demented (n = 134) and demented (n = 98) 85-year-olds. Non-demented subjects with white matter lesions (n = 46) scored significantly lower in tests of verbal ability (Synonyms), spatial ability (Block Design, Clock Test), perceptual speed (Identical forms), secondary memory (Thurstone Picture Memory), basic arithmetic (Coin Test) and the global cognitive screening test Mini-Mental State Examination than non-demented subjects without white matter lesions (n = 88). Demented subjects with white matter lesions (n = 67) scored significantly lower in tests of spatial ability (Block Design and Clock Test) and secondary memory (free recall in the MIR memory test, Ten-word memory test I and II) and in the Mini-Mental State Examination than demented subjects without white matter lesions (n = 31). It is concluded that white matter lesions contribute to cognitive decline in both non-demented and demented elderly subjects.

Aged↗
PubMedDate not supplied

NRAS mutations are rare in acute myeloid leukaemias with t(8;21) or inv(16).

Using PCR and direct sequence methodology, 19 haematologic malignancies with trisomy 8, 18 with t(8;21)(q22;q22) and 8 with inv(16)(p13q22) were screened for NRAS mutations. Of the 45 samples analyzed, 4 (9%) had a mutation; both wild-type and mutated alleles were observed in these 4 cases. Three of the mutations (involving codons 12 and 13) were found in the trisomy 8 group and 1 (codon 61) among the inv(16) samples. No specific clinical similarities were found in the 3 patients with +8 and NRAS mutation. By analyzing two sequential samples from the patient with inv(16) and NRAS mutation, it was shown that the mutation had occurred after the inversion. Since no NRAS mutations were detected among the t(8;21) samples and only 1 was found in the inv(16) group, we conclude that acute myeloid leukaemias with t(8;21) or inv(16) generally arise and progress without the involvement of NRAS mutations.

Acute Disease↗
PubMedDate not supplied

Different types of smooth muscle hypertrophy.

Smooth muscles respond to changes in their working situation by rapid and pronounced adjustments of functional and structural properties. We have examined the effects of experimental portal hypertension on the smooth muscle of the rat portal vein in a series of studies that are summarized in this review. Within one week following partial ligation of the hepatic branches of the vein, the cross-sectional area of its muscle coat increased about twofold owing to increase in the size of the individual muscle cells. The hypertrophy was associated with membrane hyperpolarization, inhibition of spontaneous electrical and mechanical activity, and reduced sensitivity to exogenous norepinephrine. Active force per unit of cross-sectional area decreased, but metabolic studies indicated improved tension economy compared with normal portal veins. The literature on different types of hypertrophy in intestinal smooth muscle, urinary bladder, and uterus is briefly reviewed. The importance of mechanical distention and chemical trophic factors as stimuli for the growth processes is discussed.

Animals↗
PubMedDate not supplied

Cerebral venous pressure during actively induced hypertension and hypercapnia in cats.

Superior sagittal sinus pressure, intracranial pressure and arterial pressure were recorded in an experimental series on 10 cats. During drug-induced, severe, acute arterial hypertension and parallel hypercapnia, venous pressure could exceed intracranial pressure in both the supra- and infratentorial compartment. From these data it is concluded that cerebral venous pressure during acute arterial hypertension may contribute to protein extravasation at the postcapillary-venular level.

Animals↗