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Biomedical subjects

K Lundgren

Publications and source records attributed to K Lundgren.

At least 73 records · Page 4Linked to original sources
PubMed1986

Acute otitis media in Sweden. Role of Branhamella catarrhalis and the rationale for choice of antimicrobial therapy.

The occurrence of Branhamella catarrhalis in the nasopharynx and middle ear exudate was investigated in 3 studies. Bacteria were isolated from the nasopharynx in 63% of 180 healthy children and B. catarrhalis, the most common bacterium present, was isolated in 36%. In 75 children with primary acute otitis media, bacteria were isolated from the nasopharynx in 98% and from the middle ear exudate in 80%. B. catarrhalis was found in the nasopharynx in 43% and in the middle ear exudate in pure culture in 9%. In those children in whom B. catarrhalis was isolated from the middle ear exudate it was also present in the nasopharynx. In 420 children, 338 with primary acute otitis media and 82 who relapsed or did not respond to previous antibiotic therapy, B. catarrhalis was isolated from the nasopharynx in approximately 50%. About half of the B. catarrhalis strains were beta-lactamase-producing and the majority of these strains were isolated in children under 3 years of age. Of children with primary acute otitis media who had beta-lactamase-producing B. catarrhalis about 50% had not previously received antibiotic treatment. B. catarrhalis is commonly found in the nasopharynx of healthy children as well as in children with acute otitis media. Many of the strains are beta-lactamase-producing though many of the children have not been previously treated with antibiotics. In middle ear exudate, B. catarrhalis is found in about 10% of cases.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed1986

Effects of alpha-naphthoflavone on levels of sister chromatid exchanges in lymphocytes from active and passive cigarette smokers: dose-response relationships.

The frequency of sister chromatid exchanges (SCE) were determined in lymphocytes of nonsmokers, passive smokers, and active smokers in the presence and absence of alpha-naphthoflavone (ANF). Higher levels of SCEs were detected for all smoking groups after in vitro addition of ANF when compared with an assay without ANF. There was a highly statistically significant difference between heavy smokers and nonsmokers (9.25 versus 7.43 SCE/cell) for the assay without ANF and for the ANF assay (14.2 versus 8.8). When considering the numerical difference in SCEs between the assays with and without ANF (delta SCE), higher values were noted for moderate smokers (2.7) and heavy smokers (4.9) compared to nonsmokers (1.4). Significant dose-response relationships were found between the frequency of SCEs and factors related to smoking, such as duration and frequency of cigarette use, tar, nicotine, carbon monoxide content of brand, and urinary measures of nicotine metabolites (cotinine and thiocyanate). No elevation of SCEs in passive smokers was found when compared to nonsmokers using either assay. The mechanism for SCE enhancement by ANF is unclear, but may be related to metabolic activation of the ANF by the cytochrome P-450 system in lymphocytes. The dosimetry relationships between cigarette smoke exposure and SCE frequency indicate that culture of human lymphocytes via ANF may provide a sensitive tool to detect exposure to cigarette smoke.

Adolescent↗
PubMed1985

Differential enhancement of sister-chromatid exchange frequencies by alpha-naphthoflavone in cultured lymphocytes from smokers and non-smokers.

The sister-chromatid exchange (SCE) frequency was assessed in peripheral lymphocytes from 4 smokers and 8 non-smokers in the absence or presence of alpha-naphthoflavone (ANF) in the culture media. ANF produced a concentration-dependent increase in the frequency of SCEs in smoking individuals. At an ANF concentration of 11 micrograms/ml, average SCE levels were 54% and 13% above the baseline levels in smokers and non-smokers, respectively. The ANF-enhanced increase in the SCE frequency ranged from 3.12 to 5.72 among smokers, and from 0 to 1.96 among the non-smokers. No significant difference in the mean SCE baseline levels between smokers and non-smokers was detected. The mechanism responsible for the enhanced frequency of SCEs in smokers following in vitro exposure to ANF is not clear, but may reflect changes in metabolic activation/deactivation or increased sensitivity to genetic effects of ANF.

Adult↗
PubMed1983

Monoclonal anti-parasite and anti-RBC antibodies produced by stable EBV-transformed B cell lines from malaria patients.

To produce human monoclonal antibodies associated with infectious disease, peripheral blood lymphocytes (PBL) from patients with Plasmodium falciparum malaria were transformed with EB-virus in vitro. To enrich for malaria-specific B cells, PBL were incubated for 3 days with unsoluble P. falciparum antigen before EBV-transformation. Furthermore, cyclosporin A was added during and after transformation to eliminate T cell suppression of B cell growth. Microcultures were screened for antibodies against blood stage antigens of P. falciparum or of noninfected erythrocytes by ELISA and indirect immunofluorescence. Cultures producing anti-P. falciparum and/or anti-erythrocyte antibodies were developed from the lymphocytes of eight patients, including some individuals with their first infection. Positive cultures were cloned and propagated for several weeks. Seven of 15 clones producing antibody at a stable rate have now been kept in cultures for more than 1 yr. Of six cultures analyzed in detail, all produced IgM antibodies of either K or lambda isotype. Although three clones were monoclonal after one cloning, three were oligoclonal. Of the former, two produced P. falciparum-specific antibodies directed to an antigen associated with the surface of merozoites. One of the oligoclonal cultures produced anti-erythrocyte antibodies, and it was probably reacting with spectrin.

Antibodies, Monoclonal↗
PubMed1983

Epidemiology of acute otitis media in children.

A prospective, longitudinal, epidemiological study of acute otitis media (AOM) in children started in Malmö in 1977 and is planned to continue for about 10 years. All cases of AOM in children are registered. The registration includes the name of the patient, the individual ten-digit birth-number and date and place of diagnosis. The registered information is supplemented with information on the patients' dwelling and type of day-care within the city at the time of diagnosis. All data are computerized. In 1977, all children up to 3 years of age were registered. In each of the following two years, a new age class was included. Since 1980 children up to 15 years have been registered. The results regarding the occurrence of AOM in 1980 show that about 10% of all children under 16 years of age had at least one episode of AOM. The disease was most common among one-year-olds, and about 30% of this age class had at least one episode. The occurrence did not vary with sex. AOM was most common during the winter season. The results of the cohort study of children born in 1977, with an observation time of maximum 48 months, show that children aged 6-11 months run the greatest risk of getting AOM. Fifty-four % of the children had at least one episode before the age of 48 months, and 48% of these children had more than one episode. There was no difference between the sexes.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗