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Biomedical subjects

M Johansson

Publications and source records attributed to M Johansson.

At least 235 records · Page 13Linked to original sources
PubMed1993

Influence of oxidized deep-frying fat and iron on the formation of food mutagens in a model system.

The effects of oxidized fats, iron and tocopherol content on the yield and species of mutagenic heterocyclic amines were studied using a model system. A mixture of glycine (0.9 mmol), creatinine (0.9 mmol) and glucose (0.45 mmol) was heated for 10 and 30 min at 180 degrees C, with the addition of iron and fats. The mutagens formed were identified and quantified using HPLC. (2-Amino-3-methylimidazo[4,5-f]-quinoxaline) (IQx), 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) and 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline (4,8-DiMeIQx) were formed in the model mixtures. The addition of iron (FeSO4) or oxidized fats to the model system did not affect the species of food mutagens formed, but the iron addition more than doubled the amount of MeIQx. The oxidation status of the fat added to the model system had little effect on the formation of MeIQx. The fat content was shown to affect the mutagen formation significantly, especially after heating for 30 min. No difference in yield of MeIQx was observed in the presence of tocopherol and tocotrienol at naturally occurring concentrations.

Chromatography, High Pressure Liquid↗
PubMed1993

Recombinations of chromosomal bands 6p21 and 14q24 characterise pulmonary hamartomas.

Cytogenetic analysis of short-term cultures from seven pulmonary hamartomas revealed an abnormal karyotype in six of them. The most characteristic aberration was an exchange of material between 6p21 and 14q24, found in three tumours. Abnormalities of either 6p or 14q were seen in another two hamartomas. Other regions that were rearranged more than once were 12q (three times) and 17p (twice), sometimes in exchange with 6p or 14q and giving rise to complex derivative chromosomes. Only one tumour had aberrations that did not involve 6p, 12q, 14q, or 17p. These results-together with the data on three previously reported pulmonary hamartomas, two of which also had t(6;14)-show that recombinations between 6p21 and 14q24 are common, and hence probably pathogenetically important. The data support the view that these tumours are genuine neoplasms rather than developmental anomalies. The coexistence of a common 14q24 breakpoint in uterine leiomyomas and pulmonary hamartomas indicates that a gene important in the genesis of both tumours exists in this band.

Adult↗
PubMed1993

Effects of edible oils and fatty acids on the formation of mutagenic heterocyclic amines in a model system.

The effects of glycerol, fatty acids and oils on the yield and species of mutagenic heterocyclic amines were studied in a model system. The addition of lipids to the model system did not affect the species of food mutagens formed, but did affect the yield of 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx). When heating creatinine, glycine and glucose dissolved in water, at 180 degrees C for 10 and 30 min, 9 and 18 nmol MeIQx/mmol creatinine were formed respectively. Corresponding figures of MeIQx formed, after addition of various fatty acids or edible oils to the model system, were as follows: oleic acid (9 and 11 nmol MeIQx/mmol creatinine), stearic acid (16 and 19 nmol), linoleic acid (8 and 16 nmol), linolenic acid (5 and 20 nmol), corn oil (10 and 33 nmol) and olive oil (10 and 28 nmol) after heating at 180 degrees C for 10 and 30 min respectively. Addition of corn or olive oil in a model system heated at 180 degrees C for 30 min, almost doubled the yield of MeIQx formed, compared with the amount formed in a model system without fat. This increase was not observed if glycerol or a fatty acid was added to the model system.

Amines↗
PubMed1993

Influenza A in immunocompromised patients.

Immunocompromised patients with influenza A were identified in Stockholm during two influenza seasons. The predominant subtypes were H3N2 during 1988-1989 and H1N1 during 1990-1991. The median age of the 25 patients was 43 years (range, 3-80 years). Twelve patients had received renal transplants and had ongoing immunosuppression. Seven patients had received bone marrow transplants between 2 days and 3 years before becoming infected with influenza virus A. Two patients were in an aplastic phase, and four had chronic graft-versus-host disease with ongoing immunosuppression. Six patients had hematologic malignancies. Two of the 25 patients had severe infections. One of these infections occurred in a bone marrow transplant recipient during an aplastic phase and was fatal; the other affected a patient who had received a renal transplant. One bone marrow transplant patient had mild but protracted infection. The remaining 22 patients had mild influenza A. We conclude that influenza A in immunocompromised patients occasionally causes severe complications but in most patients is mild and self-limiting.

Adolescent↗
PubMed1993

In situ hybridization mapping and restriction fragment length polymorphism analysis of the porcine albumin (ALB) and transferrin (TF) genes.

In situ hybridization analyses were conducted on porcine metaphase chromosomes using porcine liver albumin (ALB) and transferrin (TF) cDNA probes. The ALB gene was assigned to the q12 band of chromosome 8 and the TF gene to the q31 band of chromosome 13. For the latter, a statistically significant secondary peak was observed on the 6p15 band. However, the TF probe predominantly hybridized to the 13q31 band, indicating that this band is the most likely site of the TF gene. Since the TF gene belongs to linkage group V, this linkage group can now be assigned to chromosome 13. The TF and ALB probes were also used for restriction fragment length polymorphism (RFLP) analysis. A screening of 10 unrelated animals revealed TaqI RFLPs for both ALB and TF. Family studies indicated that the ALB and TF polymorphisms were controlled by three and two alleles, respectively.

Alleles↗
PubMed1993

A linkage group on pig chromosome 4 comprising the loci for blood group L, GBA, ATP1B1 and three microsatellites.

Restriction fragment length polymorphisms (RFLPs) were described for the porcine loci for beta-glucosidase (GBA) and the beta-polypeptide 1 of the Na+,K(+)-transporting ATPase (ATP1B1). Linkage analyses using a three-generation pedigree provided evidence for the assignment of ATP1B1, GBA and two microsatellite loci (S0001 and S0067) to a previously described linkage group comprising the loci for blood group L (EAL) and an anonymous microsatellite (S0097). The linear order of the six markers was determined with confidence by multipoint analyses and the length of the linkage group was estimated at 88cM. This linkage group was assigned to pig chromosome 4 on the basis of a previous physical localization of the ATP1B1 gene. In situ hybridization data for S0001 presented in this study were consistent with a localization on chromosome 4 and suggested a regional localization to 4p12-p13. The present study reveals conflicting data concerning the genetic localization of the K88 loci controlling the expression of the receptors for the E. coli pilus antigens. One group has reported data suggesting a loose linkage between K88 and EAL, now mapped to chromosome 4, whereas two other groups have found linkage between K88 and the transferrin locus (TF), mapped to chromosome 13 by in situ hybridization.

Animals↗
PubMed1993

Pharmacokinetic studies of cholinesterase inhibitors.

The pharmacokinetic of some centrally acting cholinesterase inhibitors that have been used to improve memory in patients with dementia of Alzheimer's type, was compared. The original compound in this class, physostigmine has an elimination half-life of 20-30 min. Galanthamine, tacrine and the metabolite 1-hydroxytacrine (velnacrine) have longer elimination half-lives of 1.6-6 hours mainly due to a larger volume of distribution. The concentration of tacrine in the cerebrospinal fluid (CSF) was less than the average plasma concentration in the dosing interval; a ratio of 0.74. The concentration of 1-hydroxytacrine and other metabolites of tacrine in the CSF were higher than the average concentrations of the compounds in plasma.

Adult↗
PubMed1993

The gene for bovine interferon gamma (IFNG) maps to the q22-q24 bands of chromosome 5 in cattle.

A approximately 700 bp bovine IFNG cDNA probe was used for the chromosomal localization of the IFNG gene in cattle using in situ hybridization technique. This locus has previously been assigned to chromosome 5 by analysis of a somatic cell hybrid panel. The in situ hybridization results obtained in the present study allow us to map the locus at the 5q22-q24 bands. Relative location of the IFNG gene and the class II cytokeratin and HOX3 gene clusters in cattle and humans is discussed.

Animals↗
PubMed1993

Early electrocardiographic changes in acute myocardial infarction treated by streptokinase or alteplase: a randomized study with dynamic, multi-lead, electrocardiographic monitoring.

Patients with a patent coronary artery after reperfusion therapy show an increased rate of evolution of QRS changes and of resolution of S-T changes as compared to patients with a persistent occlusion. Dynamic vectorcardiography permits multi-lead monitoring of changes in QRS complex and S-T segment over time. We monitored 150 patients randomized to alteplase or streptokinase for 24 h after admission. Alteplase was associated with significantly more rapid evolution of electrocardiographic changes but also with an increased occurrence of recurrent S-T changes. This may indicate a higher rate of early reperfusion with alteplase but due to recurrent ischemia, an electrocardiographic catch-up is seen with similar extent of myocardial damage observed after 24 h of monitoring.

Aged↗
PubMed1993

Chloroquine phosphate: a long-term follow-up of drug concentrations in skin suction blister fluid and plasma.

Chloroquine is known to bind strongly to melanin and is accumulated in the skin. In dermatology, the drug is mainly used to treat photosensitivity disorders, but it has also been reported to cause sun sensitivity, especially in patients with rheumatoid arthritis. In the present study the concentrations of chloroquine phosphate in plasma and skin suction blister fluid (interstitial fluid in the skin) from 16 patients were studied by HPLC at steady-state (after 2 months' ingestion of 250 mg of the drug daily) and 2, 4 and 6-7 months after cessation of therapy. At steady-state the concentrations were similar in the two compartments, whereas after discontinuation the drug remained much longer in the skin than in the plasma. In tests using cow's eye melanin in vitro, UV irradiation failed to interact with the binding of chloroquine to melanin. It is speculated that the prolonged storage of the drug in the skin could be of importance for its therapeutic as well as adverse effects.

Adult↗
PubMed1993

Distribution of acetaldehyde in human blood: effects of ethanol and treatment with disulfiram.

The distribution of free and bound acetaldehyde in human blood was studied. Fresh whole blood was precipitated with a perchloric acid (PCA) in saline solution and an aliquot of the crude sample was taken for determination of 'total' acetaldehyde. The remaining sample was centrifuged and the clear supernatant taken for analysis of 'soluble' acetaldehyde. 'Bound' acetaldehyde was calculated by subtracting soluble from total amounts. In samples collected from healthy control subjects, the acetaldehyde level in separated plasma was usually below the limit of detection of the method (0.2 microM), while much higher concentrations (> 2.5 microM) were detected when analyses were carried out on whole blood. In whole blood, about 70% was recovered as bound (i.e. PCA-insoluble) acetaldehyde. The soluble (i.e. free + PCA-soluble) level was higher than that found in separated plasma, suggesting that some acetaldehyde was liberated from the blood cells by PCA treatment. In blood spiked with ethanol, a spontaneous formation of acetaldehyde occurred during the analytical procedure. The artefactual formation increased only the soluble amount, while the bound level remained unchanged. Likewise, in samples drawn from intoxicated subjects, artefactual formation of acetaldehyde was observed in the soluble fraction, while the bound amount was not significantly increased. No significant differences in acetaldehyde levels were found between males and females, nor between healthy control subjects and alcoholic patients undergoing treatment with the aldehyde dehydrogenase inhibitor disulfiram (Antabuse). However, some of the Antabuse patients possessed elevated levels of bound acetaldehyde.

Acetaldehyde↗
PubMed1992

Pseudodiploid karyotypes in adenosquamous carcinomas of the lung.

Pseudodiploid karyotypes with clonal structural rearrangements were observed in short-term cultures from two adenosquamous carcinomas (ASC) of the lung, a tumor type hitherto virtually uncharacterized cytogenetically. The karyotypes were 46,XX,der(1)t(1;14)(q44;q22),add(9)(q34) in the first tumor and 46,XX,i(17)(q10) in the second tumor. We suggest that ASC of the lung differ from other lung cancers by having pseudodiploid instead of massively aneuploid tumor stemlines.

Aneuploidy↗
PubMed1992

Comparison of BrdUrd and [3H]TdR incorporation to estimate cell proliferation, cell loss, and potential doubling time in tumor xenografts.

In this study, two different methods of estimating cell proliferation were compared: cell loss and potential growth rate of xenografted head and neck cancer grown in nude mice based on the detection of DNA incorporation of bromodeoxyuridine (BrdUrd) in one method, and [3H]thymidine ([3H]TdR) in the other. The 21-d-old xenografts were labelled in vivo, either with BrdUrd or [3H]TdR and excised at intervals during 65.5 h. In tumors containing BrdUrd, the percent labelling was measured in mid-S and mid-G1 phase windows of cytograms from bivariate DNA flow cytometry (FCM). In [3H]TdR-labelled tumors, the percent labelled mitoses (PLM) was determined by light microscopy evaluation of autoradiographs. With a computer program based on a theoretical model, the percent labelling versus time after injection was used to analyze cell cycle time, cell loss, tumor growth fraction, and potential doubling time. The values calculated from DNA incorporation with BrdUrd agreed well with those obtained from labelling with [3H]TdR, i.e., cell cycle time 2.3 vs. 2.4 d, and growth fraction 67 vs. 70%. The estimated potential doubling time was 3.1 d and cell loss factor 40% by both methods. Flow cytometry analysis of BrdUrd-labelling is considerably faster than the evaluation of [3H]TdR-labelling, and the present results provide further support for the BrdUrd labelling method as a promising alternative to the PLM method in cell cycle studies designed to evaluate the relevance of cell proliferative properties in relation to biological behavior in xenografted head and neck cancer.

Animals↗
PubMed1992

The gene for dominant white color in the pig is closely linked to ALB and PDGRFRA on chromosome 8.

White is a widespread coat color among domestic pig breeds and is controlled by an autosomal dominant gene I. The segregation of this gene was analyzed in a reference pedigree for gene mapping developed by crossing the European wild pig and a Large White domestic breed. The gene for dominant white color was shown to be closely linked to the genes for albumin (ALB) and platelet-derived growth factor receptor alpha (PDGFRA) on chromosome 8. An unexpected phenotype with patches of colored and white coat was observed among the F1 and F2 animals. The segregation data indicated that the phenotype was controlled by a third allele, denoted patch (Ip), most likely transmitted by one of the Large White founder animals. It is shown that the ALB, PDGFRA, I linkage group shares homologies with parts of mouse chromosome 5, human chromosome 4, and horse linkage group II, all of which contain dominant genes for white or white spotting. Candidate genes for the dominant white and patch mutations in the pig are proposed on the basis on these linkage homologies and the recent molecular definition of the dominant white spotting (W) and patch (Ph) mutations in the mouse.

Albumins↗