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Biomedical subjects

C Svensson

Publications and source records attributed to C Svensson.

At least 181 records · Page 10Linked to original sources
PubMed1989

Smoking and passive smoking in relation to lung cancer in women.

In a population based case-control study the association between female lung cancer and some possible etiological agents was investigated; 210 incident cases in Stockholm county, Sweden, and 209 age-matched population controls were interviewed about their exposure experiences according to a structured questionnaire. A strong association between smoking habits and lung cancer risk was found for all histological subgroups. Relative risks for those who had smoked daily during at least one year ranged between 3.1 for adenocarcinoma to 33.7 for small cell carcinoma in a comparison with never-smokers. All histological types showed strong dose-response relationships for average daily cigarette consumption, duration of smoking, and cumulative smoking. There was no consistent effect of parental smoking on the lung cancer risk in smokers. Only 38 cases had never been regular smokers and the risk estimates for exposure to environmental tobacco smoke were inconclusive. The high relative risks of small cell and squamous cell carcinoma associated with smoking may have implications for risk assessments regarding passive smoking.

Adolescent↗
PubMed1989

Temporal bone fractures. Vestibular and other related ear sequele.

Vertigo is a common symptom after head injuries, though often overlooked in the acute stage due to other concomitant manifestations. According to previous investigations the mechanisms of injury to the vestibular system cannot be defined as clearly as for the auditory system. Twenty patients with temporal bone fractures were reviewed and later re-examined. The results of conventional X-ray, computerized tomography, clinical, otoneurological and audiological findings were analysed. The sequelae of dizziness and auditory defects were considered and follow-ups with computerized electro-oculography were performed. Radiological evaluation revealed fractures in approximately 65%. Half complained of dizziness and positional nystagmus was the most common vestibular observation. In 25% of the patients, dizziness remained to some degree. Hearing was permanently impaired in 75%. The hearing impairment depended in 20% on fractures of the ossicular chain and in 55% on sensorineural hearing loss. In those cases where a conductive hearing loss persisted, surgery on the middle ear was indicated. The vestibular system is not so vulnerable as the auditory system. Conductive hearing loss disappeared spontaneously or could be relieved by surgery. The vestibular symptoms improved or disappeared in all cases, whereas not infrequently, a sensorineural hearing loss remained.

Adolescent↗
PubMed1988

Determination of dextromethorphan and its metabolites in plasma by dual column liquid chromatography and fluorimetric detection.

Dextromethorphan and its metabolites were determined in plasma by a dual column liquid chromatographic switching system, after a prepurification on Sep-Pak C(18) cartridges. A polar precolumn (CN) and two hydrophobic analytical columns (C(18)) were used with mobile phases optimised regarding trace enrichment, selectivity and speed by the content of organic modifier. Dextromethorphan and its metabolites could be quantified at 5 ng ml(-1) with an intra-assay precision better than 6% (RSD).

Journal Article↗
PubMed1988

A comparative study on different methods of measuring Rn concentrations in homes.

Three methods of measuring 222Rn concentration in homes were compared. In 91 dwellings, measurements were made with thermoluminescence dosimeters (TLDs) for two weeks during the winter, with alpha track Track Etch type SF dosimeters (ATDs) for six months during the heating season and for one year. There was a high correlation between the TLD and the six-month ATD values (r = .83) and between the six-month and the one-year ATD values (r = .80). On the average, however, the arithmetic and geometric means of the ATD (six-month) values were approximately 50 Bq m-3 higher than the TLD values (p less than .0001). The six-month ATD values also were, on the average, approximately eight percent higher than the one-year values. This difference is probably caused by decreased ventilation during the colder part of the year. The results indicate that the measurement methods under study may be of value for exposure assessments in epidemiologic studies, but also that estimates of risk per unit radiation exposure should be interpreted with caution.

Housing↗
PubMed1988

Pancreatic atrophy follows bile-induced acute pancreatitis in the rat.

The late course of bile-induced acute experimental pancreatitis was studied in alcoholic and non-alcoholic rats. Addition of alcohol to the drinking water did, however, not influence any of the factors (see below) studied. Six hours after induction of pancreatitis the animals displayed a sixfold increase of S-amylase levels. The late mortality in the whole group of animals was 19% after 6 weeks and 71% after 12 weeks. Rats surviving 6 weeks had a marked reduction of pancreatic wet weight and of pancreatic protein, amylase, phospholipase A2, and S-glucose as compared with healthy controls. S-amylase was similar in all groups studied after 6 weeks. At light microscopy similar changes were seen after 6 and 12 weeks--that is, extensive atrophy of the exocrine pancreas with preserved islets of Langerhans. Only slight fibrosis and slight increase of inflammatory cells were seen, and no protein plugs were detected. The normal liver architecture was generally preserved, but pancreatic rats showed various degrees of bile duct proliferation. Although the morphologic findings do not correspond well with those seen in human chronic pancreatitis, we feel that they represent an integrated late phenomenon of the bile-induced pancreatitis per se, even though partial obstruction of the bile-pancreatic duct may be a co-factor.

Acute Disease↗
PubMed1987

Indoor exposure to radon from the ground and bronchial cancer in women.

A case-referent study on the possible association between radon emanating from the ground and bronchial cancer was carried out on 292 female lung cancer cases and 584 matched population referents. Both groups had lived for at least 30 years in the city of Stockholm, Sweden. The cases were diagnosed during 1972 to 1980 with oat-cell and other types of anaplastic pulmonary carcinomas. A sample of about 10% of the dwellings where cases and referents had lived was selected for measurements of radon and radon daughters. There was a relative risk of 2.2 (P = 0.01) for lung cancer associated with living in dwellings close to the ground in areas with an increased risk of radon emanation. Smoking habits did not appear to be a major confounding factor for this association, although a detailed evaluation was not possible. The measurements indicated increased radon daughter concentrations in ground level dwellings within radon risk areas where lung cancer cases had lived, suggesting that this exposure was of etiologic importance.

Adult↗
PubMed1987

'Tegaderm' dressings prevent recolonization of chlorhexidine-treated skin.

'Tegaderm', a semi-permeable, self-adhesive dressing made of polyurethane film, applied to intact upper arm skin in Intensive Care Unit (ICU) patients reduced the aerobic skin flora compared to adjacent exposed skin sites. We also applied 'Tegaderm' to skin disinfected with chlorhexidine; the aerobic skin flora remained unchanged at a low level for 5 days.

Adult↗
PubMed1987

Passive smoking and lung cancer in Swedish women.

The relation between passive smoking and lung cancer was examined by means of a case-control study in a cohort of 27,409 nonsmoking Swedish women identified from questionnaires mailed in 1961 and 1963. A total of 77 cases of primary carcinoma of the bronchus or lung were found in a follow-up of the cohort through 1980. A new questionnaire in 1984 provided information on smoking by study subjects and their spouses as well as on potential confounding factors. The study revealed a relative risk of 3.3, constituting a statistically significant increase (p less than 0.05) for squamous cell and small cell carcinomas in women married to smokers and a positive dose-response relation. No consistent effect could be seen for other histologic types, indicating that passive smoking is related primarily to those forms of lung cancer which show the highest relative risks in smokers.

Adult↗
PubMed1987

Total plasma concentrations, red blood cell concentrations, and radioreceptor assay values compared with unbound plasma concentrations of thioridazine and thioridazine metabolites in psychiatric patients.

Neuroleptic drug concentrations at the receptor sites are likely to be reflected more closely by the unbound than by the total plasma concentrations. The aim of this study was to establish whether or not the unbound plasma concentrations of thioridazine and its main nonconjugated metabolites show a stronger correlation to the red blood cell (RBC) concentration than to the total plasma concentration of the drug. The total and unbound plasma concentrations and the RBC concentrations of thioridazine and its metabolites were therefore determined in thioridazine-treated patients. "Calculated unbound concentration values" were derived from the determined total concentrations of the drug, the concentrations of drug-binding proteins, and previously determined kappa values. Since the RBC concentrations showed the best correlation to the unbound plasma values, they may be a more accurate tool than the total plasma concentrations for monitoring thioridazine treatment. The determined unbound plasma concentrations were better correlated to the calculated unbound concentrations than to the total plasma concentrations. The total plasma concentrations, but neither the unbound plasma nor the RBC concentrations, were significantly correlated to the concentrations of the drug-binding protein alpha 1-acid glycoprotein. Radioreceptor assay values were strongly correlated to the weighted sum of the total and unbound plasma concentrations of thioridazine and its metabolites.

Adolescent↗
PubMed1987

Identification of sequences in Epstein-Barr virus DNA required for the expression of the second Epstein-Barr virus-determined nuclear antigen in COS-1 cells.

The BamHI WYH region of the Epstein-Barr virus (EBV) genome encodes a protein localized to the nucleus of the infected cell, the EBV-determined nuclear antigen EBNA2. We have constructed a series of recombinant vectors that carried the complete EBNA2 gene, or the gene modified so as to contain defined deletions involving presumed exons and regulatory elements of the gene. The recombinant vectors were transfected into COS-1 cells which permit the replication of simian virus 40 origin-containing plasmids to a high copy number, and the transient expression of EBNA2 was analysed. A recombinant plasmid that carried a BglII-NotI subfragment of the BamHI WYH region (nucleotides 44664 to 50628) contained all the information necessary for inducing the expression of a full length EBNA2 polypeptide. Moreover, EBV DNA sequences between nucleotides 45,442 and 48,337 could be deleted without interfering with the ability of the vectors to induce EBNA2. On the other hand the loss of the left one-third of the BglII-NotI fragment completely abolished the EBNA2-inducing capacity of the vector. A rightward promoter consensus sequence in the BamHI W part of the BglII-NotI fragment was functional in COS-1 cells expressing EBNA2 and essential for EBV-specific RNA synthesis. The results indicated that transcription of the EBNA2 gene was initiated in the BamHI W fragment, that the transcript was spliced and that all of EBNA2 was encoded within the continuous long open reading frame in the BamHI Y and H fragments.

Animals↗
PubMed1987

A mechanism by which adenovirus virus-associated RNAI controls translation in a transient expression assay.

The mechanism by which adenovirus virus-associated RNAI stimulates translational efficiency in a transient-expression assay in 293 cells was investigated. We showed that DNA transfection leads to activation of a protein kinase that phosphorylates the alpha subunit of eucaryotic initiation factor 2 and, as a consequence, inhibition of polypeptide chain initiation. Cotransfection of a plasmid encoding adenovirus type 2 virus-associated RNAI recovered the translational capacity by preventing activation of the kinase.

Adenoviruses, Human↗
PubMed1986

X-ray crystal structure of galabiose, O-alpha-D-galactopyranosyl-(1---4)-D-galactopyranose.

O-alpha-D-Galactopyranosyl-(1---4)-D-galactopyranose, C12H22O11, Mr = 342.30, crystallises in the orthorhombic space group P2(1)2(1)2(1), and has alpha = 5.826(1), b = 13.904(3), c = 17.772(4) A, Z = 4, and Dx = 1.579 g.cm-3. Intensity data were collected with a CAD4 diffractometer. The structure was solved by direct methods and refined to R = 0.063 and Rw = 0.084 for 2758 independent reflections. The glycosidic linkage is of the type 1-axial-4-axial with torsion angles phi O-5' (O-5'-C-1'-O-1'-C-4) = 98.1(2) degrees, psi C-3 (C-3-C-4-O-1'-C-1') = -81.9(3) degrees, phi H (H-1'-C-1'-O-1'-C-4) = -18 degrees, and psi H (H-4-C-4-O-1'-C-1') = 35 degrees. The conformation is stabilised by an O-3 . . . O-5' intramolecular hydrogen-bond with length 2.787(3) A and O-3-H . . . O-5' = 162 degrees. The glycosidic linkage causes a folding of the molecule with an angle of 117 degrees between the least-square planes through the pyranosidic rings. The crystal investigated contained 56(1)% of alpha- and 44(1)% of beta-galabiose as well as approximately 70% of the gauche-trans and approximately 30% of the trans-gauche conformers about the exocyclic C-5'-C-6' and C-5-C-6 bonds. The crystal packing is governed by hydrogen bonding that engages all oxygen atoms except the intramolecular acceptor O-5' and the glycosidic O-1' oxygen atoms.

Carbohydrate Conformation↗
PubMed1986

Diagnostic accuracy of double-contrast enema and rectosigmoidoscopy in connection with faecal occult blood testing for the detection of rectosigmoid neoplasms.

Four hundred and fifty-eight consecutive subjects with a positive faecal guaiac test when screened for early detection of colorectal neoplasms were investigated with double-contrast enemas and rectosigmoidoscopy (60 cm). The results of these two methods were compared. The radiologists and endoscopists were unaware of the result of each others' examination at the time of their own investigation. Altogether ten subjects with carcinoma in the rectosigmoid area were found. The radiologists and endoscopists each overlooked four of these ten carcinomas and only four of the carcinomas were diagnosed with both methods. Fifty-six of one hundred and seven adenomas were 1 cm or larger in diameter and located in the rectum or the sigmoid colon. Thirteen of the fifty-six adenomas were missed by double contrast enema and ten by endoscopy and only thirty-three adenomas were diagnosed with both methods. Neoplasms in the rectum and the sigmoid colon are sometimes difficult to diagnose with both radiology and endoscopy. Rectosigmoidoscopy (60 cm) should therefore be used as a complement to double contrast enemas if this method is chosen for investigation of a patient with rectal bleeding.

Adenoma↗
PubMed1986

Concentrations of thioridazine and thioridazine metabolites in erythrocytes.

The concentrations of thioridazine and its main metabolites in erythrocytes from 61 thioridazine-treated patients were determined by gas-liquid chromatography. The mean and range of the erythrocyte concentrations, expressed as percentage of the corresponding plasma concentrations, were: thioridazine, 5.1% (2.0-10.6); side-chain sulfoxide, 5.6% (1.6-10.4); side-chain sulfone, 3.3% (1.1-6.8); ring sulfoxide 2.7% (0.8-4.9). The erythrocyte and plasma concentrations were significantly correlated. The erythrocyte/plasma concentration ratios, all the erythrocyte concentrations, but none of the plasma concentrations except ring sulfoxide were significantly positively correlated to the dose of thioridazine. The erythrocyte/plasma concentration ratio was not correlated to age. In vitro experiments indicated no clinically relevant erythrocyte-mediated oxidation of thioridazine.

Adult↗
PubMed1986

Defective RNA splicing in the absence of adenovirus-associated RNAI.

We have analyzed late gene expression in 293 cells infected with an adenovirus type 5 mutant dl331, which is defective in production of the low molecular weight virus-associated (VA) RNAI. The results show that several steps in late gene expression are affected. In addition to the previously characterized defect in late mRNA translation, mutant infected cells also show an aberrant selection of RNA splice sites and a substantially reduced L2, L3, and L5 mRNA accumulation. Normal or even slightly elevated amounts of mRNA from region L1 are produced. However, the L1 pre-mRNA is spliced only to generate the mRNA encoding the Mr 52,000-55,000 polypeptide and no detectable mRNA for polypeptide IIIa. Cotransfection of a plasmid encoding VA RNAI complemented the splicing defect in trans, suggesting that the abnormalities are due to the absence of VA RNAI, rather than to a cis-acting change in the nuclear precursor RNA. In a HeLa cell variant, which allows late protein synthesis also in the absence of VA RNAI, because of a lack of eukaryotic initiation factor 2 alpha kinase expression, a normal repertoire of late mRNA was produced. We conclude that a soluble factor, most likely a late viral protein, controls differential RNA splicing and late mRNA accumulation during an adenovirus infection.

Adenoviruses, Human↗
PubMed1986

Characterization of a low-molecular-weight virus-associated (VA) RNA encoded by simian adenovirus type 7 which functionally can substitute for adenovirus type 5 VA RNAI.

Human adenoviruses (Ads), like Ad type 2 (Ad2) and Ad5, encode a low-molecular-weight RNA (designated virus-associated [VA] RNAI) which is required for the efficient translation of viral mRNAs late after infection. We cloned and characterized a VA RNA gene from simian adenovirus type 7 (SA7) which appears to have biological activity analogous to that of Ad2 VA RNAI. Thus, SA7 VA RNA stimulates protein synthesis in a transient expression assay and can also functionally substitute for VA RNAI during lytic growth of human Ad5. The SA7 genome encodes only one VA RNA species, in contrast to human Ad2, which encodes two distinct species. This RNA is transcribed by RNA polymerase III in the rightward direction from a gene located at about coordinate 30 on the viral genome, like its Ad2 counterparts. SA7 VA RNA shows only a limited primary sequence homology with the Ad2 VA RNAs (approximately 55%); the flanking sequences, in fact, are better conserved than the VA RNA gene itself. The predicted secondary structure of SA7 VA RNA is, however, very similar to that of Ad2 VA RNAI, inferring that the double-stranded nature rather than the primary sequence of VA RNA is important for its biological activity.

Adenoviridae↗
PubMed1985

Adenovirus VA RNAI mediates a translational stimulation which is not restricted to the viral mRNAs.

The effect of adenovirus VA RNAI on the translation of mRNAs expressing the bacterial chloramphenicol acetyltransferase (CAT) enzyme was studied by a transient expression assay in 293 cells. The CAT activity was determined in extracts prepared from cells transfected with mixtures of plasmids encoding CAT and VA RNA. The results showed that VA RNAI co-transfection resulted in a significant increase in CAT expression from a variety of constructs. Thus, expression of CAT from a SV40 mRNA, a beta-globin mRNA and a chimeric mRNA containing the adenovirus-2 tripartite leader were all stimulated approximately 6-fold by VA RNAI. Based on these results we conclude that the tripartite leader sequence is not required for the VA RNA-mediated stimulation of translation. Our results indicate instead that VA RNAI probably functions as a general enhancer of mRNA translation. A2- to 3-fold stimulation of CAT expression was also obtained following transient expression of HeLa and CV-1 cells. The reduced efficiency was correlated with a 10- to 20-fold lower level of VA RNA expression in HeLa compared with 293 cells. Thus, it is likely that a product from region E1 indirectly enhances the translational efficiency by stimulating VA RNA transcription.

Acetyltransferases↗