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Biomedical subjects

M Leinonen

Publications and source records attributed to M Leinonen.

At least 199 records · Page 11Linked to original sources
PubMed1988

Role of type 1 and S fimbriae in the pathogenesis of Escherichia coli O18:K1 bacteremia and meningitis in the infant rat.

The role of fimbriae in the pathogenesis of Escherichia coli infection was studied in the infant rat model. Rat pups were challenged intraperitoneally at the age of 5 days with E. coli K1 (strain IH3080, O18:K1:H7) and three different subpopulations (type 1, type S, or nonfimbriated) of it. All bacterial subpopulations were able to produce peritonitis, bacteremia, and meningitis. However, the type 1 fraction was the least virulent and the type S fraction was the most virulent, as judged by the bacterial counts in body fluids and by the mortality rates of the pups. Fimbrial phase variation to mainly the type-S-fimbriated forms was observed in all body fluids. An initially type-S-fimbriated inoculum remained predominantly type S fimbriated in the peritoneal fluid and blood. In the cerebrospinal fluid, however, about 50% of the bacteria were type S fimbriated and 50% were nonfimbriated 1 h after challenge with the type-S-fimbriated subpopulation; at later times the share of type-S-fimbriated bacteria also increased in the cerebrospinal fluid.

Animals↗
PubMed1987

Enzyme immunoassay and enzyme-linked fluoroimmunoassay for detection of Chlamydia trachomatis antigen.

An enzyme immunoassay (EIA) and an enzyme-linked fluoroimmunoassay (ELFIA) utilizing monoclonal antibody to major outer membrane protein of Chlamydia trachomatis L2 were developed for rapid detection of chlamydial antigen in clinical samples. The EIA and ELFIA could detect levels of purified chlamydial outer membrane protein as low as 1.0 and 0.2 ng/ml respectively. However, when EIA and ELFIA were compared to chlamydial isolation using 160 patient samples, the sensitivity rate was 68% and 85% respectively. The sensitivity of the antigen detection method might be increased by simply using less diluted samples than in the present study. Chlamydial antigen was also demonstrated by EIA and ELFIA in 15% and 23% of culture-negative samples. The reason for these false-positive findings remains undetermined.

Antibodies, Monoclonal↗
PubMed1987

Protective efficacy of monoclonal antibodies to class 1 and class 3 outer membrane proteins of Neisseria meningitidis B:15:P1.16 in infant rat infection model: new prospects for vaccine development.

The protective efficacy of monoclonal antibodies to class 1 and class 3 outer membrane proteins of Neisseria meningitidis B:15:P1.16 was tested in an infant rat infection model. Four monoclonal antibodies to class 1 protein had bactericidal titres exceeding 20,000 and they protected infant rats completely against bacterial challenge with meningococci carrying the same class 1 protein, P1.16. One monoclonal antibody to class 3 protein was highly bactericidal (titer greater than 20,000), whereas two others had no bactericidal activity. All these antibodies gave some protection from infection, resulting in mortalities varying from 66 to 83% as compared to 100% in control rats who had received either unrelated monoclonal antibody or saline. These results strongly speak for class 1 outer membrane protein as a vaccine candidate for meningococcus group B.

Animals↗
PubMed1987

The aetiology of pneumonia. Application of bacterial serology and basic laboratory methods.

The aetiology of community-acquired pneumonia was studied by use of new bacterial and established viral serological methods besides blood culture in 162 patients. Evidence for a specific aetiology was obtained in 79 patients (49.4%). The pneumococcus was the most common aetiological agent, identified in 25.6% of cases. Other bacteria, Haemophilus influenzae, Branhamella catarrhalis, Neisseria meningitidis and Chlamydia spp. were demonstrated in 23.5%, Mycoplasma pneumonia in 1.2% and viruses in 7.4% patients. In 58% those with viral pneumonia there was evidence of mixed infection with bacteria. The predictive value of rapid laboratory tests, erythrocyte sedimentation rate, white blood cell count and C-reactive protein (CRP), was evaluated in relation to the aetiological diagnosis. They all differentiated viral from bacterial pneumonia, with CRP having the best predictive value. On the basis of these tests, most cases in which our serological tests remained negative would appear to have a bacterial aetiology also.

Aged↗
PubMed1987

Secondary cases of invasive disease caused by spread of Haemophilus influenzae type b.

Three 6-year-old girls were admitted to hospital within a period of 9 days because of invasive disease caused by Haemophilus influenzae type b (Hib). Two days after the index case contracted bacterial meningitis, her twin sister developed septicemia. Nine days after onset of illness in the index case, a day-care contact developed a febrile illness. The antibiograms of the bacterial strains isolated from cerebrospinal fluid or blood in the first two cases were identical; in the third case, blood cultures were negative but Hib antigen could be detected in serum and in urine. These cases illustrate the contagiousness of Hib disease. All household contacts of a case should be informed about the risk and their protection with rifampicin considered.

Child↗
PubMed1987

Visual thresholds measured with red test object on backgrounds of high and low luminance.

Visual thresholds measured at the central and midperipheral visual field have been tested in the eyes of a series of 10 healthy normal persons using a monochromatic red test light object (Goldmann area III, 25' of arc in the visual field) of 632 nm wavelength presented on white backgrounds of 150 cd/m2 (5000 K) and 1 cd/m2 (2800 K) luminance, as well as with no background illumination following a 45 min period of dark-adaptation. Another series of 10 normal subjects were tested with an equally large white (2800 K) test object shown on a white background of 1 cd/m2 (2800 K) luminance. Results obtained in congenital and acquired achromatopsia as well as in three relatively mild cases of rod-cone dystrophy have been related to the normal thresholds.

Adult↗
PubMed1987

Latex agglutination test for screening of Haemophilus influenzae type b carriers.

Latex agglutination (LA) for the demonstration of Haemophilus influenzae type b capsular antigen in nasopharyngeal swabs was applied to the screening of H. influenzae type b carriers and compared with culturing by the antiserum agar method on Levinthal-bacitracin plates. Altogether, 51 (33%) of the 154 nasopharyngeal specimens collected from the close contacts of patients with invasive H. influenzae type b disease were positive in LA or the antiserum agar method or both. All 40 culture-positive samples were also positive in LA, and in 11 (9.6%) culture-negative samples, H. influenzae type b antigen was demonstrated by LA. LA as used in the present study is cheap, rapid, and easy to perform and is thus an ideal tool for the screening of H. influenzae type b carriers.

Antigens, Bacterial↗
PubMed1986

Antibodies to the capsular polysaccharide of Neisseria meningitidis group B or E. coli K1 bind to the brains of infant rats in vitro but not in vivo.

The binding of monoclonal and polyclonal IgG antibodies specific to the capsular polysaccharide of Neisseria meningitidis group B and E. coli K1 was tested to the cross-reacting polysialosyl structures previously shown to be present in the brain of infant rats (Lancet 1983; ii: 355-7). Strong immunofluorescence was obtained after in vitro incubation of the brains of 1 to 13 days old rats with the antibodies whereas the brains of adult rats remained negative. The number of antibody-binding structures decreased as a function of age, being highest at the age of 1 to 5 days. However, when the same antibodies were injected intraperitoneally into the infant rat, or into the mother rat 2 days before parturition, no binding of antibodies to the infant rat brain tissue was observed.

Animals↗
PubMed1986

Vaccination of children during treatment for leukemia.

Forty-one children receiving maintenance treatment for leukemia were vaccinated with inactivated mumps virus, meningococcal polysaccharide groups A and C and polyvalent pneumococcal polysaccharide vaccines. Antibodies against pneumococcal types 3, 18C, 19F and 23F and against meningococcal groups A and C were measured by radioimmunoassay. Mumps antibodies were determined by complement fixation, hemolysis-in-gel and enzyme-linked immunosorbent assays. The antibody responses tended to be lower than those of healthy age-matched controls. The individual responses were unpredictable; the magnitude of the response correlated neither with the age nor sex of the patient, duration of the chemotherapy nor with the prevaccination antibody concentration. Nevertheless, most patients achieved and even exceeded the geometric mean of the antibody concentrations of the healthy children, considered protective against infection.

Acute Disease↗
PubMed1986

Photopic tangential perimetry.

A large absolute paracentral ring scotoma was found in both eyes of a 60-year-old woman with progressive cone dysfunction but with normal rod function using for the perimetry a white tangential screen of 200 cd/m2 luminance and a 632 nm laser test light. No visual field defect could be found in this patient using the Goldmann perimeter employing white test objects on the standard 10 cd/m2 white background. Further developments of a photopic tangential perimetry system are suggested.

Female↗
PubMed1985

Persistence of antibodies to pneumococcal vaccine in patients with chronic renal failure.

Antibody response to the 14-valent pneumococcal capsular polysaccharide vaccine was measured by the enzyme-linked immunosorbent assay (EIA) in 17 renal allograft recipients, 29 azotemic, 11 hemodialysis, and 33 control patients. The IgG, IgM, and IgA antibodies were measured against six pneumococcal antigen types 1, 3, 4, 6A, 8, and 19F. The control patients had the best antibody responses in the IgG and IgA antibody classes and the renal allograft recipients in the IgM class. The renal allograft recipients had significantly stronger antibody responses than the azotemic and hemodialysis patients. The hemodialysis patients had significantly weaker antibody responses than the control patients and the renal allograft recipients, and they also lost their antibodies most rapidly. Thus, the hemodialysis patients and probably some azotemic patients should be considered for revaccination.

Adult↗
PubMed1985

Occurrence of type-1C fimbriae on Escherichia coli strains isolated from human extraintestinal infections.

Two monoclonal antibodies specific for type-1C fimbriae of Escherichia coli were produced. In enzyme-linked immunosorbent assay and immunoblotting the antibodies, which were of the IgG1 isotype, reacted with type-1C, but not with P or type-1 fimbriae of E. coli strain KS71. Immunoblotting and immunoprecipitation of crude fimbrial extracts from 25 strains invariably gave an apparent molecular weight of 17 000 for the type-1C fimbrillin. A total of 313 E. coli strains, isolated from patients with extraintestinal infection or from faeces of healthy children, were screened for the presence of type-1C fimbriae using both the monoclonal and polyclonal antibodies. Of these, 45 (14%) strains had type-1C fimbriae, with the highest frequency (27%) on strains isolated from patients with pyelonephritis. No faecal strain had type-1C fimbriae, and the frequency on the other diagnostic groups ranged from 11 to 15%. Thus, no direct correlation between type-1C fimbriae and bacterial virulence in human extraintestinal infections was found. Type-1C fimbriae were detected on only a few E. coli serotypes, notably on all O6:K2:H1 and O22:K13:H1 strains tested.

Animals↗
PubMed1985

Comparative sensitivity of different serological tests for detecting chlamydial antibodies in perihepatitis.

The value of several serological tests was assessed by studying sera from 30 women with clinical findings of perihepatitis and a high chlamydial antibody titre in the indirect immunofluorescence antibody test (IFAT). The other tests included the complement fixation test and enzyme immunoassays in which the antigen comprised either partially purified particles (EIA kit) or purified major outer membrane protein (MOMP EIA) of Chlamydia trachomatis L2 or lipopolysaccharide isolated from an Re mutant of Salmonella (Re LPS EIA). High IgG titres were noted in most (88-96%) of the patients by MOMP EIA and EIA kit, and in fewer patients (50%) by Re LPS EIA or complement fixation test. Seroconversion was found in 11-44% of the patients for IgG and in 28-36% for IgM; high IgG titre was thus the best diagnostic indicator for each test. The enzyme immunoassay tests have the advantage of being automated either with partially purified corpuscular or purified MOMP antigen and would allow a sensitive easy screening for chlamydial aetiology of women with pain of the right upper quadrant.

Antibodies, Bacterial↗