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Biomedical subjects

H Soini

Publications and source records attributed to H Soini.

At least 37 records · Page 2Linked to original sources
PubMed1999

Complex transmission dynamics of clonally related virulent Mycobacterium tuberculosis associated with barhopping by predominantly human immunodeficiency virus-positive gay men.

Limited data suggest that measures to reduce tuberculosis transmission should be based on locations rather than on personal contacts. Molecular epidemiologic methods (analysis of IS6110 patterns, spoligotypes, variable numbers of tandem DNA repeats, and automated DNA sequence data) identified a cohort of 48 persons who were infected with progeny of the same Mycobacterium tuberculosis strain. Epidemiologic investigation documented that a large proportion of the patients were gay white human immunodeficiency virus-positive men. Most practiced barhopping, an activity that involved patronizing many bars in the same neighborhood each night. Few subjects were directly linked to more than 1 or 2 other persons by conventional investigation methods, which shows that the transmission dynamics were unusually complex compared with most previously described episodes of strain spread. The data support the concept that identification of locations where pathogen dissemination likely occurs may provide additional strategies for targeted tuberculosis control.

Alcohol Drinking↗
PubMed1999

Extensive cross-contamination of specimens with Mycobacterium tuberculosis in a reference laboratory.

A striking increase in the numbers of cultures positive for Mycobacterium tuberculosis was noticed in a mycobacterial reference laboratory in Campinas, Sao Paulo State, Brazil, in May 1995. A contaminated bronchoscope was the suspected cause of the increase. All 91 M. tuberculosis isolates grown from samples from patients between 8 May and 18 July 1995 were characterized by spoligotyping and IS6110 fingerprinting. Sixty-one of the 91 isolates had identical spoligotype patterns, and the pattern was arbitrarily designated S36. The 61 specimens containing these isolates had been processed and cultured in a 21-day period ending on 1 June 1995, but only 1 sample was smear positive for acid-fast bacilli. The patient from whom this sample was obtained was considered to be the index case patient and had a 4+ smear-positive lymph node aspirate that had been sent to the laboratory on 10 May. Virtually all organisms with spoligotype S36 had the same IS6110 fingerprint pattern. Extensive review of the patients' charts and investigation of laboratory procedures revealed that cross-contamination of specimens had occurred. Because the same strain was grown from all types of specimens, the bronchoscope was ruled out as the outbreak source. The most likely source of contamination was a multiple-use reagent used for specimen processing. The organism was cultured from two of the solutions 3 weeks after mock contamination. This investigation strongly supports the idea that M. tuberculosis grown from smear-negative specimens should be analyzed by rapid and reliable strain differentiation techniques, such as spoligotyping, to help rule out laboratory contamination.

Bacteriological Techniques↗
PubMed1999

Prevalence of Borrelia burgdorferi in Ixodes ricinus ticks in urban recreational areas of Helsinki.

Lyme borreliosis, an infection caused by the tick-borne spirochete Borrelia burgdorferi, is a major health problem for populations in areas of endemicity in the Northern Hemisphere. In the present study we assessed the density of ticks and the prevalence of B. burgdorferi sensu lato among ticks in popular urban recreational areas of Helsinki, Finland. Altogether 1,688 Ixodes ricinus ticks were collected from five areas located within 5 km of the downtown section of Helsinki, and 726 of them (303 nymphs, 189 females, and 234 males) were randomly chosen for laboratory analysis. The midguts of the ticks were divided into three pieces, one for dark-field microscopy, one for cultivation in BSK-II medium, and one for PCR analysis. Ticks were found in all the study areas; their densities varied from 1 to 36 per 100 m along which a cloth was dragged. The rate of tick infection with B. burgdorferi sensu lato varied from 19 to 55%, with the average being 32%. Borellia afzelii was the most predominant genospecies in all the areas, and no B. burgdorferi sensu stricto isolates were detected. Only two ticks were concurrently infected with both B. afzelii and Borrelia garinii. Dark-field microscopy gave more positive results for B. burgdorferi than did cultivation or PCR analysis. However, the agreement between all three methods was fairly good. We conclude that Lyme borreliosis can be contracted even in urban environments not populated with large mammals like deer or elk. The disease should be taken into account in the differential diagnosis of certain symptoms of patients from these areas, and the use of measures to improve the awareness of the general population and health care officials of the risk of contracting the disease is warranted.

Animals↗
PubMed1998

Survey of drug-resistant tuberculosis in northwestern Russia from 1984 through 1994.

The morbidity, mortality, and relapse rates of tuberculosis have increased in the Russian Federation since 1991. Increased drug resistance may be one reason for the weakened efficacy of local tuberculosis treatments. Laboratory data on tuberculosis resistance were collected from a survey area that included two republics and seven other administrative regions (oblasts) with a total population of more than 14 million. Susceptibility data from 1991 through 1994 were available from all nine regions; data on resistance to individual drugs and data from 1984 through 1994 were available from the Leningrad region and the city of St. Petersburg. From 1991 through 1994. the annual notification rate of tuberculosis increased in the survey area by 53.7% (from 25.1 to 38.6 cases per 100000 inhabitants), tuberculosis mortality doubled (from 4.4 to 9.2 deaths per 100000), and primary resistance to at least one drug increased from 17% (95% CI, 14.9-19.9) to 24% (95% CI, 22.2.-25.8). The prevalence of primary resistance to at least isoniazid and rifampin (multidrug resistance) was 5.1% in the Leningrad region in 1992 through 1994. The proportion of pulmonary isolates with secondary multidrug resistance increased from 21.6% (95% CI 7.9-25.3%) in the period 1984-1994 to 33% (95% CI 29.7-36.3%) in 1989-1994. Even if these figures are biased upwards because of selection, it can be concluded that secondary resistance to tuberculosis drugs was already prevalent in northwestern Russia ten years ago. Since then, a distinct shift towards multidrug resistance has occurred. The lower prevalence of primary multidrug resistance raises hopes that the resistance problem can be controlled with properly designed and monitored therapeutic measures.

Antibiotics, Antitubercular↗
PubMed1998

Genotypic characterization of drug-resistant Mycobacterium tuberculosis isolates from Peru.

SETTING: Twenty-nine epidemiological unrelated and mostly multidrug-resistant Mycobacterium tuberculosis (MDR-TB) strains from Peruvian patients. OBJECTIVE: To investigate the molecular genetics of MDR-TB strains recovered in a Latin American country. DESIGN: Antimicrobial agent susceptibility testing, major genetic group designation, IS6110 fingerprinting, spoligotyping, and automated deoxyribonucleic acid sequencing of regions of the katG, rpoB, embB, gyrA, and pncA genes with mutations commonly associated with drug resistance. RESULTS: Nineteen isolates were found to be multidrug-resistant by susceptibility testing. IS6110 typing showed that virtually all isolates were unique and therefore had independently acquired drug resistance. Seventy-nine percent of isoniazid-resistant strains had a Ser315Thr amino acid change in KatG. Ninety-five percent of rifampin-resistant isolates had amino acid replacements in the rifampin-resistance determining region of RpoB. Six of 11 ethambutol-resistant strains had EmbB alterations. Eleven pyrazinamide-resistant strains had distinct mutations in pncA. CONCLUSION: Virtually all organisms evolved drug resistance independently. The types of drug resistance-associated mutations identified were very similar to changes occurring in isolates from other areas of the world. Nucleotide sequence-based strategies for rapid detection of drug resistance-conferring mutants will be applicable to organisms recovered in Peru, and potentially other areas of Latin America.

Amidohydrolases↗
PubMed1998

Rapid detection of rifampin-resistant Mycobacterium tuberculosis by sequencing and line probe assay.

Resistance to rifampin (RMP) is associated with mutations in the rpoB gene. Disk elution method, direct DNA sequencing and line probe assay were compared in rapid detection of rpoB mutations from 30 Mycobacterium tuberculosis isolates. Concordance between LiPA and culture was 93.3%, whereas sequencing yielded 100% concordance with culture. These results indicate that line probe assay is nearly as sensitive a method as sequencing in rapid detection of RMP-resistance of M. tuberculosis isolates, and can be applied in laboratories working with standard PCR equipment.

Antibiotics, Antitubercular↗
PubMed1998

A novel erythromycin resistance methylase gene (ermTR) in Streptococcus pyogenes.

Erythromycin resistance among streptococci is commonly due to target site modification by an rRNA-methylating enzyme, which results in coresistance to macrolide, lincosamide, and streptogramin B antibiotics (MLSB resistance). Genes belonging to the ermAM (ermB) gene class are the only erythromycin resistance methylase (erm) genes in Streptococcus pyogenes with MLSB resistance that have been sequenced so far. We identified a novel erm gene, designated ermTR, from an erythromycin-resistant clinical strain of S. pyogenes (strain A200) with an inducible type of MLSB resistance. The nucleotide sequence of ermTR is 82.5% identical to ermA, previously found, for example, in Staphylococcus aureus and coagulase-negative staphylococci. Our finding provides the first sequence of an erm gene other than ermAM that mediates MLSB resistance in S. pyogenes.

Amino Acid Sequence↗
PubMed1998

A Ser315Thr substitution in KatG is predominant in genetically heterogeneous multidrug-resistant Mycobacterium tuberculosis isolates originating from the St. Petersburg area in Russia.

Parts of katG and rpoB from 27 Russian Mycobacterium tuberculosis isolates were sequenced to detect mutations causing resistance to isoniazid (INH) and rifampin (RMP), respectively. All 24 INH-resistant isolates had a mutated katG, and 22 of them (91.7%) carried a mutation coding for a Ser315Thr shift. An rpoB mutation was noted for each of the 21 RMP-resistant isolates, with Ser531Leu being the most prevalent change encoded. Only two isolates had identical IS6110 fingerprints.

Bacterial Proteins↗
PubMed1998

Education students' description of learning 'disabilities'.

295 first- and fourth-year students in the College of Education at the University of Saskatchewan, Canada were asked to describe learning disabilities. When the descriptors they used were categorized, nonparticipation in the classroom formed the largest single category.

Adolescent↗
PubMed1997

False-negative serological HLA-B27 typing results may be due to altered antigenic epitopes and can be detected by polymerase chain reaction.

Serological typing with the microlymphocytotoxicity test (MLCT) and flow cytometry (FC) using HLA-B27 antisera is commonly used for the determination of HLA-B27. However, in some patients tested more than once, negative results have turned out to be positive at following investigations. We retested by polymerase chain reaction (PCR) samples from 20 randomly selected patients with reactive arthritis or Reiter's syndrome who had now been followed for 20 yr. Ten of the patients were originally tested to be HLA-B27 positive and 10 HLA-B27 negative by the MLCT. All 10 serologically HLA-B27 positive individuals were also positive in the PCR. However, 2/10 patients interpreted as being HLA-B27 negative were positive by PCR. At this time, the same two patients were also positive in the routine MLCT and FC using four different monoclonal antibodies against HLA-B27. PCR is superior to serological techniques to determine HLA-B27 positivity unequivocally, since it is based on the detection of HLA-B27 gene sequences.

Aged↗
PubMed1997

Gene amplification in the diagnosis of mycobacterial infections.

The number of importance of infections caused by Mycobacterium tuberculosis and other mycobacterial species is increasing. Since the detection and identification of mycobacteria by conventional laboratory methods (cultivation, staining, and biochemical tests) is a slow and complex procedure, rapid diagnostic methods are urgently needed. Several amplification methods based on different techniques have been applied in the detection of mycobacteria directly from clinical specimens. Most experience has been obtained from different polymerase chain reaction (PCR) assays and their general performance is good. However, their sensitivity in the analysis of samples containing small amounts of mycobacteria or samples containing inhibitory substances has been low. Furthermore, the risk of false positives caused by contamination is high, and the clinical relevance of the results may be unclear. Thus, these gene amplification techniques are a valuable adjunct to the diagnosis of mycobacteria, but so far they cannot replace conventional microbiological methods.

Gene Amplification↗
PubMed1997

Diversity of the 32-kilodalton protein gene may form a basis for species determination of potentially pathogenic mycobacterial species.

In this study, partial gene sequences of the mycobacterial 32-kDa protein gene were determined by PCR-based sequencing. A total of 50 strains representing 18 potentially pathogenic mycobacterial species were studied. In 10 cases, all three strains of the species studied were identical, and intraspecies variability was found in 6 cases. Thus, the 32-kDa protein gene may be a good target for identification of mycobacteria by PCR-based sequencing.

Amino Acid Sequence↗
PubMed1996

katG mutations in isoniazid-resistant Mycobacterium tuberculosis isolates recovered from Finnish patients.

katG and inhA genes from isoniazid-resistant Mycobacterium tuberculosis strains isolated in Finland were examined by PCR or sequencing. By PCR, katG was not detected in 3 of 54 strains. Sequencing of katG from 13 strains showed small point mutations or insertions; a previously described mutation causing a Ser-to-Thr change at position 315 was found in 4 strains, and there were nine new missense mutations of katG. A 209-bp segment of inhA from 17 strains was sequenced, but no mutations were observed. This result indicates that different mutations prevail in different geographical areas.

Antitubercular Agents↗
PubMed1996

Genetic diversity among Mycobacterium avium complex AccuProbe-positive isolates.

The partial 32-kDa-protein gene sequences of 22 Mycobacterium avium complex (MAC) clinical isolates that were positive by the AccuProbe MAC probe only (not by the M. avium or M. intracellulare probe) were determined. The obtained nucleotide sequences were compared with the published sequences for M. tuberculosis, M. avium, and M. intracellulare by a sequence analysis program. There was a wide range of genetic diversity among the strains studied. Most of them (16 of 22) had sequences similar but not identical to those of M. avium and M. intracellulare. These strains were considered to be true MAC strains. Five strains had sequences in the category of the novel MAIX sequence, which was very different from the sequences of other mycobacteria analyzed thus far. In addition to these strains, one isolate had a sequence that differed greatly from the reference sequences. These results support previous findings showing that the MAC probably contains several additional species. Our results also suggest that the MAC AccuProbe may react with strains that do not belong to the MAC.

Bacterial Proteins↗
PubMed1996

Comparison of amplicor and 32-kilodalton PCR for detection of Mycobacterium tuberculosis from sputum specimens.

The commercial PCR test Amplicor was compared with the 32-kDa PCR for detection of Mycobacterium tuberculosis from 76 sputum specimens from Egyptian patients. Both tests performed with rather equal efficacy (resolved sensitivity of 88.9% for both tests; specificity of 98.0% for Amplicor and 93.9% for 32-kDa PCR). PCR was found to be useful in detection of auramine fluorescent stain-positive, culture-negative specimens.

DNA, Bacterial↗
PubMed1994

Maltooligosaccharides as chiral selectors for the separation of pharmaceuticals by capillary electrophoresis.

Complexation between the linear maltodextrin oligosaccharides and certain enantiomeric compounds of pharmaceutical interest in buffered solutions can lead to an analytically desirable chiral recognition. Different maltodextrins were assessed in their capacity to cause enantiomeric separations under various conditions of capillary electrophoresis. The mechanism of chiral recognition has been probed through electrophoretic mobility and selectivity measurements for different buffer solutions and organic solvent additives. A differential interaction of chiral solutes with the maltodextrin helical entities emerges as the basis of such enantioselectivity. This notion is further supported by 1H- and 13C-NMR experiments. Optimized separations of simendan, ibuprofen, warfarin, and ketoprofen enantiomers are demonstrated together with a chiral determination of ibuprofen in a blood serum sample at the therapeutic level.

Blood Chemical Analysis↗
PubMed1994

Mixed polymer networks in the direct analysis of pharmaceuticals in urine by capillary electrophoresis.

Two-component polymer mixtures of polyethylene oxide-polydextran have been investigated as unique separation media for capillary electrophoresis. The effects of concentration of the individual polymers and their mixtures on the electroosmotic velocity and electrophoretic mobility of small pharmaceutical compounds were investigated. The molecular masses of polymers, buffer concentrations and percentages of organic solvents and cyclodextrins were varied to explore their effects on the separation process. The plate height against field strength curves were also generated for a better understanding of the kinetic processes involved. The two-component polymer mixtures were found as stable and selective media for the analysis of an anti-ulcer drug famotidine directly in untreated urine.

Buffers↗