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Biomedical subjects

C Påhlson

Publications and source records attributed to C Påhlson.

At least 19 recordsLinked to original sources
PubMed2000

Antibacterial activity of human prostasomes.

BACKGROUND: Prostasomes are prostate-derived organelles in semen exhibiting pluripotent properties. The present study deals with their possible antibacterial effects. METHODS: Antibacterial activity was assessed by growth inhibition of bacteria in an incubation medium containing prostasomes, after which the incubate was inoculated on cystine lactose electrolyte deficient agar (CLED) plates. In cases involving Bacillus megaterium, the effects were also documented ultrastructurally with scanning electron microscopy and atomic force microscopy. RESULTS: A dose-dependent growth inhibition was apparent, and a complete inhibition of growth was seen at a prostasome protein concentration of 30 microg/ml with Bacillus megaterium. Ultrastructurally, increasingly irregular contours and a loosening of the smooth surface were observed, combined with a fragmentation of the bacteria. Among 9 other bacterial strains tested, a complete growth inhibition by prostasomes was attained in 3 strains, while the other 6 were unaffected. CONCLUSIONS: Our data suggest that prostasomes, or prostasome-derived proteins, are responsible for the antibacterial effects on Bacillus megaterium and some other bacterial strains. The results may serve as a basis of development of a new class of antibacterial drugs.

Bacillus megaterium↗
PubMed1999

Association of Rickettsia helvetica with chronic perimyocarditis in sudden cardiac death.

BACKGROUND: Rickettsia helvetica is the only non-imported rickettsia found in Scandinavia. It was first detected in Ixodes ricinus ticks, but has never been linked to human disease. We studied two young Swedish men who died of sudden cardiac failure during exercise, and who showed signs of perimyocarditis similar to those described in rickettsial disease. METHODS: Samples from the heart and other organs were analysed by PCR and DNA sequencing. May-Grünwald-Giemsa, Grocott, and acridine-orange stains were used for histopathological examinations. Staining of R. helvetica grown on shell-vials in vero cells, and the early descriptions of R. rickettsii by H T Ricketts and S B Wohlbach served as controls. Immunohistochemistry was done with Proteus OX-19 rabbit antisera as the primary antibody. The structure of rickettsia-like organisms was investigated by transmission electron microscopy. Serological analyses were carried out by indirect immunofluorescence with R. helvetica as the antigen. FINDINGS: By use of a semi-nested PCR, with primers specific for the 16S rRNA and 17-kDa outer-membrane-protein genes, and sequence analysis of the amplified products, genetic material from R. helvetica was detected in the pericardium and in a lymph node from the pulmonary hilum in case 1, and in a coronary artery and the heart muscle in case 2. A serological response in case 1 revealed an endpoint titre for R. helvetica of 1/320 (1/256 with R. rickettsii as the antigen). Examination of PCR-positive tissue showed chronic interstitial inflammation and the presence of rickettsia-like organisms predominantly located in the endothelium. These organisms reacted with Proteus OX-19 antisera, and their size and form were consistent with rickettsia. Electron microscopy confirmed that the appearance of the organisms was similar to that described for spotted-fever rickettsia. INTERPRETATION: R. helvetica, transmitted by I. ricinus ticks, may be an important pathogen in the aetiology of perimyocarditis, which can result in sudden unexpected cardiac death in young people.

Adult↗
PubMed1999

Rickettsia helvetica in Ixodes ricinus ticks in Sweden.

In the present study further characterization of the amplified sequence of the citrate synthase gene of the spotted fever group Rickettsia isolated from Ixodes ricinus ticks in Sweden showed that it has 100% homology with the deposited sequence of the citrate synthase gene of Rickettsia helvetica. The restriction fragment length polymorphism (RFLP) pattern of an amplified 382-bp product of the citrate synthase sequence, defined by primers RpCS877 and RpCS1258, yielded fragments for our isolate that could be visualized as a double band that migrated at approximately 44 bp, another double band at 85 bp, and a single band at nearly 120 bp after digestion with the restriction enzyme AluI. When calculating a theoretical PCR-RFLP pattern of the sequence of the citrate synthase gene of R. helvetica from the known positions where the AluI enzyme cuts, we arrived at the same pattern that was obtained for our isolate, a pattern distinctly different from the previously published PCR-RFLP pattern for R. helvetica. Investigation of 125 living I. ricinus ticks showed a higher prevalence of rickettsial DNA in these ticks than we had found in an earlier study. Rickettsial DNA was detected by amplification of the 16S rRNA gene, for which a seminested primer system consisting of two oligonucleotide primer pairs was used. Of the 125 ticks, some were pooled, giving a total of 82 tick samples, of which 20 were found to be positive for the rickettsial DNA gene investigated. When considering the fact that some of the positive samples were pooled, the minimum possible prevalence in these ticks was 20 of 125 (16%) and the maximum possible prevalence was 46 of 125 (36.8%). These prevalence estimates conform to those of other studies of spotted fever group rickettsiae in hard ticks in Europe.

Animals↗
PubMed1997

Characterization of a spotted fever group Rickettsia from Ixodes ricinus ticks in Sweden.

A spotted fever group rickettsia isolated from the common tick, Ixodes ricinus, was genetically characterized by PCR and genomic sequencing. This study was performed with nymphal and adult ticks collected in southern and central Sweden. I. ricinus is the only North European tick species of medical importance which is regularly collected from humans. No species of the genus Rickettsia has previously been found in Scandinavian ticks, nor has any case of domestic rickettsial infection in humans or animals been reported. According to the nucleotide sequencing, the present Rickettsia sp. belongs to the spotted fever group of rickettsiae. Ticks are the most common arthropod reservoirs and vectors of the rickettsiae of this group. Among 748 ticks investigated, 13 (1.7%) were positive for a Rickettsia sp. Borrelia burgdorferi was detected in 52 (7%) of the ticks, a prevalence similar to or somewhat lower than that previously been recorded in other Swedish studies. There was no evidence of ehrlichial or chlamydial DNA in these ticks. The Rickettsia sp. was further characterized by 16S ribosomal DNA (rDNA) sequencing and restriction fragment length polymorphism (RFLP). The 16S rDNA sequencing resulted in a sequence identical to that described for Rickettsia helvetica, but the pattern obtained with RFLP of the citrate synthetase gene diverged from previously known patterns. The rickettsial agent of one tick which was positive by PCR was confirmed by transmission electron microscopy. The morphology of this rickettsia was similar to that of the spotted fever and typhus group rickettsiae. This represents the first documented isolate of a Rickettsia sp. from Swedish ticks.

Animals↗
PubMed1997

Phylogenetic placement and characterization of a new alpha-2 proteobacterium isolated from a patient with sepsis.

An alpha-2 proteobacterium, previously unknown as determined by its phylogenetic characteristics and the DNA sequence of its 16S rRNA gene, was isolated from a patient who presented an unusual clinical picture, including high remitting fever and multiorgan involvement. The bacterium was detected in multiple plasma samples, obtained during the acute phase of the disease, after cocultivation in cell culture media. Electron microscopy of the organism showed a three-layer laminar cell wall and electron-dense granules within the cytoplasm, as well as a polar flagellum. By means of PCR followed by sequencing of amplified 16S ribosomal DNA fragments, the bacterium was found to differ from all species for which ribosomal sequence information is available. It is here provisionally named the Rasbo bacterium. At a subsequent relapse, the bacterium was identified in pericardial fluid both by PCR/sequencing and by direct electron microscopy. At a second relapse, it was again cultured from plasma. After in vitro adaptation to solid media, the MICs of various antibiotics could be determined. A transient immunoglobulin M (IgM) but no IgG response to the bacterium was found by an indirect immunofluorescence test, as well as by an immobilization test during the acute phase of the disease.

Adult↗
PubMed1997

High incidence of Chlamydia pneumoniae in sclerotic heart valves of patients undergoing aortic valve replacement.

Chlamydia pneumoniae has previously been demonstrated in the atherosclerotic lesions of various arteries, including the coronary arteries, and has been proposed to play a role in the pathogenesis of atherosclerosis. A prospective study of the incidence of C. pneumoniae in the sclerotic valves of patients undergoing aortic valve replacement because of aortic stenosis and in the aortic valves of cases dying of non-cardiac reasons and undergoing forensic autopsy was undertaken. The results were correlated to serological markers of past (IgG) or persistent (IgA) C. pneumoniae infection. C. pneumoniae, as determined by the polymerase chain reaction (PCR), was detected in the aortic valve in 19/39 (49%) patients and in 1/11 (9%) autopsy controls (p = 0.018) and confirmed by electron microscopy in one patient. There was no significant difference in the incidence rate of IgG or IgA antibody positivity between PCR-positive and PCR-negative cardiac patients. These results extend the hypothesis of a pathogenic role of C. pneumoniae in atherosclerosis to include also aortic valve sclerosis.

Adult↗
PubMed1996

An increase in sudden unexpected cardiac deaths among young Swedish orienteers during 1979-1992.

BACKGROUND: Sixteen cases of sudden unexpected cardiac death, 15 males and one female, are known to have occurred among young Swedish orienteers from 1979 to 1992, of which seven cases occurred between 1989 and 1992. This is considered to be indicative of an increased death rate. RESULTS: Histopathological evaluation showed myocarditis in a higher than expected proportion of cases. In one such case, which we studied before the sudden unexpected death occurred, the victim had suffered a Chlamydia pneumoniae infection verified by serology, and a nucleotide sequence was found in the heart and lung by means of the polymerase chain reaction (PCR) that hybridized with a probe specific for that organism. Male Swedish orienteers do not, however, seem to have an increased rate of exposure to this agent. No further sudden unexpected deaths among young orienteers have occurred over the past 3.5 years. At the beginning of that period, attempts were made to modify training habits and attitudes.

Adolescent↗
PubMed1994

A late exclusion of bacteriophage T4 can be suppressed by Escherichia coli GroEL or Rho.

A litCon mutation in Escherichia coli TU6 results in exclusion of bacteriophage T4 during the late, morphogenetic stage of its development at low temperatures. DNA was synthesized continuously in the infected cells, but less than 10% of the DNA made by 90 min after infection was packaged into DNAase-resistant particles, few viable phage were formed, and the cells lysed poorly. The exclusion could be relieved by conditions leading to elevated levels, determined immunologically, of the E. coli Rho protein (believed to be involved in regulation of T4 transcription), or chromosomally encoded E. coli GroEL (a chaperone known to be involved in phage assembly), or by supplying GroEL in trans from a plasmid. The two suppressing proteins appeared to act independently of each other. GroEL-suppression restored packaging to normal levels, perhaps by preventing GP23 from activating the host Lit protein; in addition DNA synthesis was delayed and reduced and cell lysis enhanced, demonstrating involvement of GroEL in both these processes. Rho suppression was less efficient. Since both transcription-termination-proficient and transcription-termination-deficient Rho suppressed, the results raise the possibility that Rho has a role during T4 development not directly involving transcription regulation.

Bacterial Proteins↗
PubMed1994

Detection of bacterial DNA in cerebrospinal fluid by an assay for simultaneous detection of Neisseria meningitidis, Haemophilus influenzae, and streptococci using a seminested PCR strategy.

Primers specific to conserved and variable regions in the 16S rRNA sequence were selected from the partially sequenced 16S rRNA genes of Neisseria meningitidis, Haemophilus influenzae, Streptococcus pneumoniae, S. agalactiae, and Staphylococcus epidermidis. The PCR assay was divided into two DNA amplifications. The first resulted in a general bacterial amplicon, and the second resulted in a species-specific amplicon. The high specificity of the PCR assay was documented after testing bacteria of 28 different species (133 strains). A total of 304 clinical cerebrospinal fluid samples, including 125 samples from patients with bacterial meningitis, were assayed to investigate the diagnostic sensitivity and specificity for bacterial meningitis. The assay showed high sensitivity (0.94) and specificity (0.96) with the clinical samples, although some false results were obtained, the reasons for which are discussed. With agarose gel electrophoresis for detection of the PCR products, the detection limit for meningococci in cerebrospinal fluid was 3 x 10(2) CFU/ml.

Base Sequence↗
PubMed1992

Incidence of pelvic inflammatory disease after first-trimester legal abortion in women with bacterial vaginosis after treatment with metronidazole: a double-blind, randomized study.

OBJECTIVE: The purpose of this study was to evaluate the effect of metronidazole treatment on the incidence of postoperative pelvic inflammatory disease after first-trimester abortion in women with bacterial vaginosis. STUDY DESIGN: A double-blind, randomized, multicenter study was conducted on 231 women undergoing first-trimester legal abortion and fulfilling the criteria for bacterial vaginosis. The women were randomized to either metronidazole 500 mg three times daily for 10 days or placebo. Treatment was started at the outpatient visit the week before the operation. RESULTS: Among the 174 women who could be evaluated, pelvic inflammatory disease developed in 14 after the abortion. In the treatment group there were three infections (3.8%) compared with 11 (12.2%) in the placebo group (p less than 0.05). CONCLUSION: These data suggest that patients with bacterial vaginosis should be treated in conjunction with first-trimester abortion because treatment with metronidazole reduces the postoperative infection rate more than three times.

Abortion, Induced↗
PubMed1992

Immunomagnetic recovery of Chlamydia trachomatis from urine with subsequent colorimetric DNA detection.

There is need for integrated systems that provide rapid and sensitive diagnosis of Chlamydia trachomatis. Here we describe for the first time that specific antibodies to a C. trachomatis surface protein can be used for magnetic recovery of bacteria directly from crude urine samples. The combination of immunomagnetic separation (IMS), where the bacterial cells are both purified and concentrated, with a colorimetric PCR assay makes the method sensitive and suitable for routine clinical screening in microtiter format. No filtrations, centrifugations, extractions, or electrophoretic techniques are required throughout the whole procedure. Using magnetic beads as the solid phase, the colorimetric detection of immobilized amplified nucleic acids (DIANA) also allow direct DNA sequencing of positive samples for more detailed analysis. Of the 27 urine samples analyzed, eight were found to be positive using this method. Only five out of these eight were determined to be positive by cell culture.

Adult↗
PubMed1992

Detection and identification of Mobiluncus species by direct filter hybridization with an oligonucleotide probe complementary to rRNA.

A hybridization assay for direct detection and identification of Mobiluncus species has been developed and tested. A [32P]-labelled synthetic oligonucleotide probe, complementary to a nucleotide sequence in the variable region V8 of Mobiluncus 16S ribosomal RNA, was utilized. One of the advantages of using rRNA as target molecule for the hybridization assays is the copy number of rRNA, which can be as high as 10(4), and that additionally three to six sites on the minus strand of the DNA gene can be utilized. This probe was found to be sensitive and to react with 62 of 68 tested typical or atypical Mobiluncus isolates. It was also specific, and was shown not to react with 96 tested unrelated bacterial species and isolates, including taxonomically closely related species like Actinomyces or Bifidobacterium spp., or with bacteria isolated from the vagina of both healthy persons with an undisturbed flora, as well as from patients suffering from the bacterial vaginosis syndrome (BV).

Bacteroidaceae↗
PubMed1991

The ecologically wrong vaginal lactobacilli.

Morphologically different Lactobacilli can be observed in wet smear preparations from the lower female genital tract; this morphological difference seems to correlate with the ability of the bacterium to produce hydrogen peroxide. This discussion will examine the role of the normal bacterial flora in protection of the host against recurrent infections. Further, we will propose a model as to how the potential role of immunological tolerance or 'immunological preference for' the maternal bacterial flora, can give individual differences in disposition for infections.

Female↗
PubMed1991

An increased number of gamma/delta T-cells and gastric epithelial cell expression of the groEL stress-protein homologue in Helicobacter pylori-associated chronic gastritis of the antrum.

Numerous studies have shown that the presence of Helicobacter pylori in the stomach is linked to the development of chronic gastritis most commonly seen in the antrum. However, the pathogenic mechanisms are unclear. In 23 of 31 patients, examined due to symptoms from the upper gastrointestinal tract, H. pylori-associated chronic gastritis of the antrum was diagnosed histologically and by growth of H. pylori. Immunoperoxidase staining on gastric biopsy specimens from these patients showed an increased number of gamma/delta T-cells within the epithelium. Furthermore, the Mab ML30 (raised against the 65 kDa heat shock protein of mycobacteria) demonstrated positive staining in the gastric epithelial cells in all H. pylori-positive but not in H. pylori-negative biopsy specimens. H. pylori also reacted with ML30, as detected by immunoperoxidase staining as well as by immunoblotting. Intraepithelial gamma/delta T cells may play a role in host defense against invading H. pylori, and the bacteria may trigger an autoimmune response to stress proteins expressed by the gastric epithelial cells.

Adult↗
PubMed1991

Clue cells in predicting infections after abdominal hysterectomy.

Seventy women scheduled for abdominal hysterectomy were examined for the presence of clue cells in the vaginal discharge in an attempt to identify a possible risk group for development of postoperative infection. Seven of 20 women (35%) with clue cells developed vaginal cuff infections or wound infections, compared with four of 50 women (8%) without clue cells (P less than .01). Women with bacterial vaginosis, diagnosed by air-dried vaginal smears, are therefore at risk for postoperative infection.

Adult↗
PubMed1990

Treatment of bacterial vaginosis in women with vaginal bleeding complications or discharge and harboring Mobiluncus.

A double-blind study of treatment for bacterial vaginosis (BV), using metronidazole tablets 500 mg 3 times daily for 10 days versus placebo in the same regimen, was performed on 42 outpatients with irregular bleeding episodes or discharge attending a gynecological clinic. All patients had motile rods in wet smears in addition to fulfilling the criteria for BV. Treatment gave a cure rate of 76% versus 5% in the placebo group. Mobiluncus sp. was identified in 81% of these cases before treatment, in 8% of the cured patients and in 50% of those not initially cured at follow-up. Repeated treatments, once or twice, resulted in a 100% cure rate. A 6-month follow-up was carried out on 39 of the 42 patients. There were 7 relapses after 6 months giving a cure rate of 82%. After successful treatment all bleeding disturbances disappeared. We conclude that it is important to treat BV in patients with symptoms other than malodorous discharge.

Adult↗
PubMed1989

Association of Campylobacter pylori with induced expression of class II transplantation antigens on gastric epithelial cells.

Campylobacter pylori was identified with immunoperoxidase staining and a mouse monoclonal antibody directed against C. pylori in gastric biopsy specimens from 24 patients with gastritis. C. pylori was not found in gastric biopsy specimens from six subjects with histologically normal mucosa. The monoclonal antibody, which was reactive with a surface protein of approximately 20 kilodaltons, was found to be specific for C. pylori, and the immunoperoxidase staining proved to be more sensitive and rapid than culture in detecting the organism. In the tissue specimens where C. pylori was detected with the monoclonal antibody, there was a strong expression of class II transplantation antigens on the epithelial cells and an increased number of T lymphocytes. These findings indicate that C. pylori may initiate local immune responses.

Antibodies, Monoclonal↗