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Biomedical subjects

U Lindberg

Publications and source records attributed to U Lindberg.

At least 109 records · Page 6Linked to original sources
PubMed1978

Selective assay of monomeric and filamentous actin in cell extracts, using inhibition of deoxyribonuclease I.

A simple and selective assay for monomeric and filamentous actin is presented, based on the inhibition of DNAase I by actin. In mixtures of monomeric and filamentous actin, only the monomeric form is measured as DNAase inhibitor. The total amount of actin in a sample can be determined after depolymerization of F actin with guanidine hydrochloride. The assay is rapid enough to detect changes in the polymerization state of actin in vitro over time intervals as short as 3 min. Data characterizing unpolymerized and filamentous actin pools in extracts of human platelets, lymphocytes and HeLa cells are presented.

Actins↗
PubMed1978

Asymptomatic bacteriuria in schoolgirls. VIII. Clinical course during a 3-year follow-up.

A 3-year follow-up of 116 schoolgirls with asymptomatic bacteriuria, treated or untreated is reported. It is concluded that bacteria isolated from girls with asymptomatic bacteriuria do not commonly cause symptomatic pyelonephritis and that the risk of developing renal damage as a result of asymptomatic bacteriuria in a schoolgirl with a roentgenographically normal urinary tract seems to be small. It is also suggested that for the majority of these patients therapy is not necessary.

Adolescent↗
PubMed1978

Adhesion to normal human uroepithelial cells of Escherichia coli from children with various forms of urinary tract infection.

The ability to adhere to normal human uroepithelial cells was compared for Escherichia coli strains isolated from the urine of girls with acute pyelonephritis, acute cystitis, or asymptomatic bacteriuria, and from the stools of school children without bacteriuria. Strains from those with acute pyelonephritis had high adhesive ability, whereas strains from those with acute cystitis had intermediate and strains from girls with asymptomatic bacteriuria or from normal feces had low adhesive ability. Strains of serogroup O4K12 had good adherence regardless of origin. E. coli of the eight O groups commonly found in patients with acute pyelonephritis adhered more than did strains of other O groups. Spontaneously agglutinating strains had less adhesive ability than did the O-typable ones.

Acute Disease↗
PubMed1977

Comparison of Escherichia coli from bacteriuric patients with those from feces of healthy schoolchildren.

The properties of 709 strains of Escherichia coli isolated from feces of healthy schoolchildren were compared with those of 115 strains from the urine of girls with asymptomatic bacteriuria (ABU) detected in a screening program. These fecal strains were also compared with 45 strains that caused asymptomatic reinfections and 10 that caused symptomatic reinfections in the same group of girls. Typing of O antigen was done by direct bacterial agglutination, and K typing was done with a serum agar technique. Hemolytic capacity was assessed in solid medium. Sensitivity to the bactericidal effect of normal serum and minimal inhibitory concentrations of ampicillin were also determined. The strains isolated from girls who had reinfections of ABU were found to be a random sample of the fecal flora, but the strains from children with symptomatic reinfection were not. Strains from index patients with ABU differed from the other groups in a way that was indicative of adaptive changes in the structure of cell envelopes.

Adolescent↗
PubMed1977

Antigens of Escherichia coli, human immune response, and the pathogenesis of urinary tract infections.

Acute pyelonephritis (but not cystitis or "asymptomatic" bacteriuria) due to Escherichia coli induces serum antibodies to O-but rarely to K-antigens, especially not to the most common antigen, K1. Locally produced secretory IgA and IgG antibodies to O-and K-antigens appear in urine during most infections. The E. coli in urine of patients with asymptomatic bacteriuria are different from those in patients with acute pyelonephritis and cystitis and undergo continuous changes, presumably caused by the local antibody response. The E. coli become less virulent and are less able to attach to uroepithelial cells than E. coli causing acute symptomatic infections. Antibodies in urine prevent epithelial adherence. Parenteral and intravesicular injections of killed bacteria can protect against ascending pyelonephritis in rats. A few K-antigens dominate among E. coli that cause urinary tract infections. Vaccination of problem cases is a possibility because of the protective nature of K-antibodies. The mechanism of renal scarring that appears in some patients with urinary tract infections is unknown. Autoantibodies to the Tamm-Horsfall protein that increase after acute pyelonephritis or the cross-reactions noted between certain E. coli and antigens on the kidney may be involved.

Animals↗
PubMed1977

Characterization of mRNA-protein complexes from mammalian cells.

In a previous report we described the use of oligo(dT)-cellulose for the isolation of mRNA-protein complexes from EDTA-dissociated polysomes extracted from normally growing or adenovirus infected KB-cells (I). Experiments presented here provide evidence that proteins involved in these complexes bind specifically to mRNA since: a) the proteins and mRNA cosediment through sucrose gradients, b) they adsorb and elute from oligo(dT)-cellulose together, and c) analysis of the products from ribonuclease digestion experiments show that the poly (A) end and a separate small fraction of the mRNA are resistant to the enzymes and attached to protein.

Adenoviridae↗
PubMed1977

Asymptomatic bacteriuria in schoolgirls. VI. The correlation between urinary and faecal Escherichia coli. Relation to the duration of the bacteriuria and the sampling technique.

The occurrence of the urinary strain in the anus, rectum and faeces was investigated in 27 girls with asymptomatic bacteriuria (ABU). In patients with bacteriuria of relatively short duration 46% of the faecal isolates were of the urinary strain as compared to only 18% in patients with bacteriuria of relatively long duration. In general the correlation between the urinary and faecal flora is striking at the time of establishment of ABU but diminishes with time. The diminished correlation may be due to two factors: firstly, the composition of the faecal flora changes with time. Secondly, the correlation may be obscured by complex changes in the properties of bacterial strains established in the urinary tract. Contamination by the infected urine did not seem to be a serious problem when the rectal mucosa was swabbed proximal to the anal canal.

Anal Canal↗
PubMed1977

Asymptomatic bacteriuria in schoolgirls. VII. A follow-up study of the urinary tract in treated and untreated schoolgirls with asymptomatic bacteriuria.

The urinary tracts of 116 schoolgirls with asymptomatic bacteriuria detected at screening were investigated by excretory urography and micturition cystourethrography. Three years later the studies were repeated in 11 patients with scarred kidneys, 11 patients with unscarred kidneys plus reflux, and 14 untreated patients with radiologically normal urinary tracts. Exceptionally small scarred kidneys showed little growth. Unscarred kidneys with vesico-ureteral reflux exhibited normal growth, as did unscarred kidneys in untreated patients. The risk of kidney damage developing as a result of asymptomatic bacteriuria in a schoolgirl with a radiologically normal urinary tract seems to be small.

Adolescent↗
PubMed1977

Differences in antigenicity of Escherichia coli strains isolated from patients with various forms of urinary tract infections.

The antibody amounts to crude O antigens were analyzed using the enzyme-linked immunosorbent assay (ELISA) and the indirect hemagglutination (IHA) technique in 42 sera from 6 rabbits. The rabbits were hyperimmunized with one of the WHO Escherichia coli standard strains O1, O2 or O75. In the antibody assays the O antigens were obtained from E. coli strains isolated from 15 patients with asymptomatic bacteriuria (ABU), from 3 patients with acute pyelonephritis and from the WHO E. coli strains used for the immunization. The strains from the patients belonged to serogroup O1, O2 or O75. Significantly higher IgG and IgM antibody levels were detected with the ELISA when using the O1 and O2 but not O75 antigens from the pyelonephritis and WHO standard strains than when using the antigens from the ABU strains. Using the IHA technique the O1, O2 and O75, IgG and IgM antibody titers against the antigens from the pyelonephritis and WHO standard strains were significantly higher than those against the antigens from the ABU strains. In inhibition experiments the antigens from the strains causing pyelonephritis inhibited the reaction between antigen on solid phase and antibodies in solution much more efficiently than did antigens from strains causing ABU.

Animals↗
PubMed1976

Variable adherence to normal human urinary-tract epithelial cells of Escherichia coli strains associated with various forms of urinary-tract infection.

The ability to become attached to normal epithelial cells from the urinary tract was much greater in Escherichia coli bacteria isolated from the urine of patients with acute symptomatic pyelonephritis or cystitis than in those isolated from the urine of patients with asymptomatic bacteriuria. Attachment of the bacteria could be prevented by incubation in urine containing antibodies against the strain tested. The ability to attach to uroepithelial cells might be a virulence factor for E. coli strains which cause symptomatic urinary-tract infection.

Acute Disease↗
PubMed1976

Depolymerization of F-actin by deoxyribonuclease I.

Deoxyribonuclease I causes depolymerization of filamentous muscle actin to form a stable complex of 1 mole DNAase I:1 mole actin. The regulatory proteins tropomyosin and troponin bind to filamentous actin and slow down but do not prevent the depolymerization. In the absense of ATP, heavy meromyosin binds tightly to actin filaments and blocks completely the DNAase I: actin filament interaction. Addition of ATP releases heavy meromyosin; DNAase I is then rapidly inhibited and the actin filaments are depolymerized.

Actins↗
PubMed1976

Anti-actin specificity of human smooth muscle antibodies in chronic active hepatitis.

Thirty sera reacting by IFL technique in titres greater than or equal to 100 with smooth muscle fibres of rat stomach, rat renal glomeruli, and with the membrane region of thyroid cells were randomly chosen among sera sent in for routine testing of tissue antibodies. All sera but one were found to be derived from patients with chronic active hepatitis. The smooth muscle and other relevant cell staining were abolished after absorption of sera with actin, prepared from rabbit skeletal muscle and found to be homogeneous by SDS gel-electrophoresis and by electron microscopy. The actin anti-bodies were purified by precipitation of sera with F-actin and elution of the precipitates at acid pH. The purified antibodies stained all tissues in the same way as the original sera. In double immunodiffusion tests all thirty sera gave precipitation with actin. Thus, it was concluded that these broad-reacting SMA are directed against actin. The finding of high-titred SMA is of diagnostic value and supports the clinical diagnosis of active chronic hepatitis. In addition, anti-actin antibodies eluted from human sera are a suitable tool for studying actin-containing cellular structures.

Actins↗