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Biomedical subjects

M Leinonen

Publications and source records attributed to M Leinonen.

At least 181 records · Page 10Linked to original sources
PubMed1991

Antibody response to pneumococcal capsular polysaccharide vaccine in African children.

Antibody titers to six pneumococcal polysaccharides were measured by enzyme-linked immunosorbent assay in Gambian children before and 1 month after vaccination with a 23-valent pneumococcal capsular polysaccharide vaccine at the ages of 2, 4, 6 or 9 months or at 5 to 10 years of age. IgG responses to type 1, 3 and 5 polysaccharides were seen in children in all age groups. Responses to type 19F and 23F polysaccharides were seen only in the oldest children. Few children of any age responded to immunization with type 6A pneumococcal polysaccharide. The immune response of Gambian infants to immunization with six components of a polyvalent pneumococcal polysaccharide vaccine was comparable with that described previously in Finnish infants and would be unlikely to provide substantial protection against invasive pneumococcal disease.

Antibodies, Bacterial↗
PubMed1991

Mixed infection is common in children with respiratory adenovirus infection.

The presence of concomitant viral or bacterial infection was evaluated in 20 patients hospitalized for adenovirus infection of the middle or lower airways by using new serological methods for detection of both antigens and antibodies. Adenovirus infection was identified by measurement of antibodies with complement fixation test or by direct detection of viral antigen in nasopharyngeal aspirates. Mixed infection was present in 11 (55%) of the 20 patients. Viral coinfection was demonstrated in five (25%) and bacterial in nine (45%) patients. Bacterial coinfection was common, 67%, in children with an infection focus, pneumonia or acute otitis media, but rare, 13%, in those without it. Seroconversion to nontypable Haemophilus influenzae was indicated in six children; four of them were infants, four had pneumonia and three acute otitis media. Pneumococcal infection was indicated in two patients with pneumonia, both aged over two years. Chlamydia trachomatis was involved in one case. The results indicate that bacterial coinfection is common in respiratory adenovirus infection affecting lower airways, especially if pneumonia is present.

Acute Disease↗
PubMed1991

Evaluation of a new tube latex agglutination test for detection of type-specific pneumococcal antigens in urine.

A modified tube agglutination test using type-specific latex reagents for detection of pneumococcal capsular polysaccharide antigens in alkalinized, unconcentrated urine samples was evaluated in reconstituted urine samples and in groups consisting of 26 children with clinical and roentgenographic evidence of acute lower respiratory tract infection, six patients with blood culture-proven infection of nonpneumococcal etiology, and 30 healthy individuals. The sensitivity of the tube latex agglutination method for pneumococcal polysaccharides was 2 to 10 times higher than that of the slide agglutination method. Positive antigen findings were obtained for 42% of urine samples from patients with acute lower respiratory tract infection but in neither patients with nonpneumococcal septicemia nor healthy controls. Fifty-five percent of the antigen-positive patients also showed evidence of pneumococcal involvement by pneumococcal antibody assay or antigen detection in acute-phase serum.

Antigens, Bacterial↗
PubMed1991

Rod thresholds in dominantly inherited juvenile optic atrophy.

Three members of a family with dominantly inherited juvenile optic atrophy with tritan type of colour vision deficiency all showed dysfunction of the rod mechanism tested with green light after 30 min of dark adaptation. Two subjects had typical optic atrophy, centrocaecal scotoma and lower than normal visual acuity. In 1 subject with good visual acuity of both eyes, no optic atrophy was observed, but there were, in this case, reduced peripheral parts of the standard visual fields.

Adult↗
PubMed1991

Serum adenosine deaminase in viral and bacterial pneumonia.

We measured the activity of serum adenosine deaminase (ADA) in paired sera from 171 military conscripts with radiographically verified pneumonia. Patient serum samples were selected on the basis of serologic analyses identifying as single etiologic agents Streptococcus pneumoniae in 29 patients, Haemophilus influenzae in 7, Mycoplasma pneumoniae in 43, adenovirus in 24, influenza A or B in 12, and parainfluenza in 5 patients. In 14 patients Neisseria meningitidis and in 31 Chlamydia spp were considered the main etiologic agent. Compared with a control group of 45 healthy men, the ADA activity in patients with pneumonia was significantly higher (p less than 0.001) in all patient groups except those with meningococcal pneumonia. The highest ADA levels were seen in patients with pneumonia caused by M pneumoniae (27.4 +/- 9.7 U/L), Chlamydia spp (26.3 +/- 9.1 U/L), and adenovirus (28.5 +/- 10.9 U/L) compared with the controls (11.1 +/- 3.0 U/L). In patients with meningococcal pneumonia, the ADA activity was significantly decreased (p less than 0.001). Serum ADA activity probably reflects differences in cellular immune response to different infectious agents. The ADA determinations may give corroborative information on the etiologic agent of pneumonia.

Adenosine Deaminase↗
PubMed1990

Circulating immune complexes containing chlamydial lipopolysaccharide in acute myocardial infarction.

The presence of circulating immune complexes (IC) was studied using two detection methods specific for chlamydial lipopolysaccharide (LPS) in paired serum samples of 44 patients (30 men and 14 women) with acute myocardial infarction (AMI). Forty-four random controls were individually matched for locality, age and sex with the AMI patients. As specificity controls for the IC assays single serum samples from 29 patients with diseases characterized by the presence of circulating IC were used. Fifty-seven per cent of AMI patients, 12% of their random controls and 10% of the patient controls were shown to have chlamydial LPS-specific immune complexes in their sera (P less than 0.0001, AMI versus random and patient controls). This finding provides further evidence of the possible association of chronic chlamydial infection with AMI.

Adult↗
PubMed1990

Bacterial involvement in parainfluenza virus infection in children.

37 children with serologically confirmed parainfluenza virus (PV) infection were studied by new serological methods for evidence of concomitant bacterial infection. 24 of the children were hospitalized because of croup and 13 because of lower respiratory tract infection. Serological evidence of bacterial involvement was found in 4 (11%) of the 37 children, in none of the 24 children with croup but in 31% of the 13 children with PV infection of the lower airways (p less than 0.05). Streptococcus pneumoniae was implicated in 3 cases and Haemophilus influenzae in 1. Serological evidence of staphylococcal involvement was not seen in any case. The 3 patients with pneumococcal involvement had pneumococcal antigen in the acute serum. In all of them pneumonia was associated with PV type 1 or 3, and in 2 serum C-reactive protein was elevated. The data presented support the view, that secondary bacterial infection is rare in children with croup, but common in lower respiratory tract infection caused by PV.

Acute Disease↗
PubMed1990

Aetiology, outcome and prognostic factors in community-acquired pneumonia requiring hospitalization.

Outcome and prognostic factors were prospectively studied in 277 adult patients (average age 62 yrs) with community-acquired pneumonia requiring hospitalization. The aetiology was established in 68%, with S. pneumoniae as the predominating agent. Mortality was 4% (12 of 277), and all but one who died were greater than or equal to 60 yrs of age. Features associated with high mortality included greater age, absence of chills and chest pain, high respiratory rate (greater than 30 breaths.min-1) and low serum albumin on admission, and the occurrence of airway colonization and secondary infection during hospital stay. Multivariate analysis showed that low serum albumin and the occurrence of secondary infection, but also absence of chills and airway colonization, were correlated to a higher mortality. In patients who survived, the median length of hospital stay was seven days, and at follow-up, about eight weeks after admission, 81% had recovered and chest X-ray was normal in 84%. In conclusion, we believe that the outcome of community-acquired pneumonia can be influenced by prophylactic measures against pneumococcal infection, and an increased surveillance of risk patients.

Adolescent↗
PubMed1989

Comparative evaluation of potential components for group B meningococcal vaccine by passive protection in the infant rat and in vitro bactericidal assay.

Seventeen monoclonal antibodies to one of three main cell surface antigens of Neisseria meningitidis group B were tested for protective efficacy in the infant rat using as challenge seven strains of different class 2/3 protein serotypes, class 1 protein (P1) subtypes and LPS immunotypes. Type-specific protection indicated both by a reduction of bacteraemia and meningitis and survival of the animals was regularly obtained with antibodies to the P1 protein and to LPS. By contrast, only one of seven antibodies to the serotype-specific class 2/3 protein was protective, even though four of them were highly bactericidal. The animal protection test and in vitro bactericidal assay were otherwise concordant. These data form important guidelines for the design of vaccines to prevent group B meningococcal infections.

Animals↗
PubMed1989

Measurement of antibody responses to pneumolysin--a promising method for the presumptive aetiological diagnosis of pneumococcal pneumonia.

An enzymeimmunoassay (EIA) for measuring antibodies to pneumococcal pneumolysin has been developed. The method was used to study the possible pneumococcal aetiology of pneumonia in 159 mostly elderly patients admitted to hospital because of a positive chest X-ray. The results obtained with the assay were compared to those obtained by other diagnostic methods, namely blood culture, detection of pneumococcal antigen in urine and demonstration of an antibody response to pneumococcal C-polysaccharide and capsular polysaccharides. Antibody response to pneumolysin was found in 32 of 39 (82%) patients with pneumococcal pneumonia aetiologically diagnosed presumptively by other methods. In addition, the EIA for pneumolysin antibodies was positive in 31 patients without evidence of pneumococcal aetiology by other methods. The clinical and laboratory investigations of these patients supported the presumption of bacterial infection. We conclude that the EIA we have developed for measuring pneumolysin antibodies is a promising, sensitive method for the presumptive aetiological diagnosis of pneumococcal pneumonia. The assay is simple to perform because only one antigen is needed and measurement of IgG antibodies alone seems to be enough for aetiological diagnosis.

Adolescent↗
PubMed1989

Mixed bacterial and viral infections are common in children.

Acute phase and convalescent sera from 51 pediatric patients who had a documented viral infection and no obvious culture-confirmed bacterial infection such as meningitis, otitis media or urinary tract infection were tested by enzyme immunoassay for antibodies to Haemophilus influenzae and Branhamella catarrhalis and by the latex agglutination test for pneumococcal antigens to evaluate the frequency of mixed bacterial and viral infections. A mixed bacterial and viral infection was documented in 19 patients (37%). Seven patients (14%) showed a diagnostic rise in antibodies to H. influenzae and 8 patients (16%) showed an antibody elevation to B. catarrhalis in their paired sera; pneumococcal antigen was detected in acute phase serum from 4 patients (8%). The rate of mixed infections in patients having respiratory symptoms was 52%. High serum C-reactive protein values and white blood cell counts were found significantly more often in those with mixed infections than in those who had viral infections. The results indicate that mixed bacterial and viral infections occur more frequently in children than one could anticipate on the basis of the earlier reports. Mixed bacterial and viral etiology is highly probable in a child who has a defined viral infection with high C-reactive protein and white blood cell count values, especially in the presence of respiratory symptoms.

Adolescent↗
PubMed1989

Bacterial coinfection in children hospitalized with respiratory syncytial virus infections.

Clinical and bacterial findings were prospectively studied in 90 children hospitalized because of middle or lower respiratory tract infection caused by respiratory syncytial virus (RSV) during a surveillance period of 12 months. The results were compared with those of RSV-negative children hospitalized with identical indications during the 3 peak months of the RSV epidemic (N = 91) or for the 3 months after the outbreak (N = 99). A high frequency of pneumonia and acute otitis media were found in both RSV-positive and RSV-negative children during the epidemic, but not in control patients after the epidemic. Bacterial infection, based on a significant rise of antibody titer and/or on detection of pneumococcal antigen in serum or urine, was observed in 39% of the children with RSV infection. The respective figures were 24% in RSV-negative children hospitalized during the epidemic and 8% after the epidemic. Our observations stress the role of RSV as a predisposing agent for secondary bacterial infection in the airways of children. The most common bacteria involved in the mixed RSV-bacterial infections were Streptococcus pneumoniae and Haemophilus influenzae, the latter being found only in pneumonic patients. The presence or absence of pneumonia or acute otitis media was not significantly correlated with evidence of pneumococcal infection. We conclude that a bacterial pathogen should be actively sought when managing patients with lower respiratory tract syndromes, especially in those who have evidence of RSV infection.

Acute Disease↗
PubMed1988

Serological evidence of an association of a novel Chlamydia, TWAR, with chronic coronary heart disease and acute myocardial infarction.

Paired sera from 40 male patients with acute myocardial infarction (AMI), 30 male patients with chronic coronary heart disease (CCHD), and 41 controls, matched for sex, age, time, and locality were investigated for antibodies to a novel type of Chlamydia sp, TWAR, and to chlamydial lipopolysaccharide (LPS) group antigen. 27 patients with AMI (68%), and 15 (50%) patients with CCHD had raised IgG (greater than or equal to 128) and/or IgA (greater than or equal to 32) titres in the microimmunofluorescence test with chlamydia TWAR. Both frequencies were significantly higher than in the controls (7, 17%). 26 (68%) of 38 patients with AMI also showed a significant seroconversion in enzyme immunoassay with LPS antigen; this response was absent in all patients with CCHD and all but 1 of the controls. Chronic chlamydial infection could be a factor in the pathogenesis of cardiovascular diseases.

Adult↗
PubMed1988

Etiological diagnosis of pneumonia in military conscripts by combined use of bacterial culture and serological methods.

The combined use of microbiological, serological and clinical laboratory methods was evaluated for etiological diagnosis of pneumonia in 106 military conscripts. Special attention was paid to rapid diagnosis of pneumococcal pneumonia and its differentiation from viral and mycoplasmal pneumonia. The microbial etiology could be established in 91 (86%) of the pneumonia patients. Pneumococcal etiology was definitely established in 32 (30%) patients and considered probable in an additional 21 patients (20%). Infection with Mycoplasma pneumoniae and adenovirus was confirmed in 23 (22%) of the patients. Mixed infections was observed in 28 (31%) of the patients with established etiology. Detection of pneumococcal antigen was the best rapid diagnostic method, being positive in 90% of the patients with purulent sputum samples in the group with a definite diagnosis of pneumococcal pneumonia prior to the start of antimicrobial treatment, while Gram stain was positive in only 65% of these patients. Sputum purulence could be used to differentiate very significantly pneumococcal from viral and mycoplasmal pneumonia (p less than 0.001). These categories of pneumonia could also be successfully differentiated by clinical laboratory tests, of which the white blood cell count and C-reactive protein were most useful. The suggested cut-off value for the cell count was 10 X 10(9)/l, and for C-reactive protein 85 mg/l. These tests could not differentiate viral from mycoplasmal pneumonias.

Adult↗