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Biomedical subjects

H Fredlund

Publications and source records attributed to H Fredlund.

At least 19 recordsLinked to original sources

[Prevention and early diagnosis of cancer. What do we know? What do we think? Reports from the Lakardagarna in Orebro].

Läkardagarna (physician days) in Orebro is an annual course arranged by the Orebro Society of Medicine in collaboration with The Swedish Society of Medicine. In the year 2000 the title was "Prevention and early diagnosis of cancer. What do we know? What do we believe? What do we do?" With general practitioners as the target audience, the course covered basic biological science, risk factors, screening, ethical questions and the general practitioner's dilemma. This article reviews four selected contributions: 1) What is cancer? 2) Possible importance of the fetal stage for later risk of cancer; 3) Infections as a cause of cancer; and 4) Screening for cancer.

Health Knowledge, Attitudes, Practice↗

The effects of live Streptococcus pneumoniae and tumor necrosis factor-alpha on neutrophil oxidative burst and beta 2-integrin expression.

OBJECTIVE: To study the effects of TNF-alpha and live Streptococcus pneumoniae on human neutrophil oxidative burst and beta 2-integrin expression using flow cytometry. METHODS: Six clinical isolates of S. pneumoniae (serotypes 3, 19A, 22F, 6A, 33F and 9N) from patients with bacteremic pneumonia or upper respiratory tract infections were studied. Whole blood was incubated either alone, with TNF-alpha or with S. pneumoniae or with both TNF-alpha and pneumococci at a ratio of one neutrophil per 1--5 bacteria. After 30 min of incubation, the tubes were put into ice, fixed and analysed. RESULTS: S. pneumoniae caused an increase in oxidative burst but not greater than that caused by TNF-alpha alone. When whole blood was preincubated with TNF-alpha for 30 min before the addition of pneumococci, a further increase in the oxidative burst response was seen. The variation in CD11b expression was not significant. Both S. pneumoniae and TNF-alpha caused increases in CD18 expression. The addition of TNF-alpha directly with the bacteria caused no further increase, but preincubation of blood with TNF-alpha 30 min before the addition of the bacteria caused a significant increase in CD18 expression. CONCLUSIONS: Live S. pneumoniae stimulates polymorphonuclear leukocytes to produce an oxidative burst and increases expression of CD18, and these effects are enhanced by TNF-alpha.

Bacteremia↗

Epidemiology of the reemergence of gonorrhea in Sweden.

BACKGROUND: After many years of decline, the incidence of gonorrhea in Sweden reached an all-time low of 2.4 cases per 100,000 inhabitants in 1996; however, the incidence has been increasing since 1997. GOAL: To describe the reemergence of gonorrhea in Sweden using clinical epidemiologic data and microbiologic characterization of isolated strains of Neisseria gonorrhoeae. STUDY DESIGN: N gonorrhoeae strains isolated in Sweden from February 1998 to January 1999 were serotyped and an epidemiologic data questionnaire was sent to each clinician reporting a case of gonorrhea. RESULTS: Epidemiologic and microbiologic data were obtained for 357 cases (91% of all cases diagnosed during the period). Domestic cases had significantly increased since 1997. Serovar IB-3 was the most common isolate in domestic cases of heterosexually exposed teenagers, and serovar IB-2 was the most frequent isolate in domestic cases of homosexually exposed men. Of the imported cases, 47% were exposed in Asia and 6.5% were exposed in Eastern Europe. CONCLUSION: The increase of gonorrhea in Sweden is due to an increase of domestic cases. Heterosexual teenagers and homosexual men were identified as core groups infected by different serovars of N gonorrhoeae.

Adolescent↗

Characterization of Chlamydia trachomatis omp1 genotypes among sexually transmitted disease patients in Sweden.

A method for detection and genotyping of genital Chlamydia trachomatis infections based on omp1 gene amplification and sequencing was developed. DNA was extracted from urogenital or urine samples using a Chelex-based method, and an approximately 1,100-bp-long fragment from the omp1 gene was directly amplified and sequenced. Genotyping was performed by BLAST similarity search, and phylogenetic tree analysis was used to illustrate the evolutionary relationships between clinical isolates and reference strains. The method was used to determine the genotypes of C. trachomatis in 237 positive urogenital and/or urine specimens collected at a Swedish sexually transmitted disease clinic during 1 year. The most common genotypes corresponded to serotypes E (47%) and F (17%). The omp1 gene was highly conserved for genotype E (106 of 112 samples without any mutation) and F (41 of 42 samples without any mutation) strains but appear slightly less conserved for genotypes G (n = 6) and H (n = 6), where the sequences displayed one to four nucleotide substitutions relative to the reference sequence. Genotyping of samples collected at the follow-up visit indicated that two patients had become reinfected, while three other patients suffered treatment failure or reinfection. One woman appeared to have a mixed infection with two different C. trachomatis strains. This omp1 genotyping method had a high reproducibility and could be used for epidemiological characterization of sexually transmitted Chlamydia infections.

Adolescent↗

Comparison of serogroup W-135 meningococci isolated in Sweden during a 23-year period and those associated with a recent hajj pilgrimage.

An outbreak of serogroup W-135 meningococcal disease was reported among pilgrims returning from the annual hajj (pilgrimage to Mecca) in mid-March 2000. Molecular characterization was used to investigate the similarity of the hajj-associated W-135 strains with those isolated in Sweden during a 23-year period (1978 to 2000). The same hajj-associated genosubtype, genosubtype P1.5,2,36b, has been documented in Sweden since 1979, while pulsed-field gel electrophoresis and the sulfadiazine resistance of the W-135 isolates indicated that the outbreak was probably due to a new clone of W-135 meningococci.

Disease Outbreaks↗

The effects of live Neisseria meningitidis and tumour necrosis factor-alpha on neutrophil oxidative burst and beta2-integrin expression.

The effects of human recombinant tumour necrosis factor-alpha (TNF-alpha) on neutrophil (PMNL) oxidative burst and on CD11b/CD18 and CD14 expression after stimulation with pathogenic or nonpathogenic Neisseria meningitidis were studied using chemiluminescence and flow cytometry. PMNL oxidative burst increased more when stimulated with the apathogenic 29E strain than with the pathogenic B strain both when studied by chemiluminescence and by flow cytometry. When TNF-alpha was added to whole blood or PMNL together with bacteria a significant increase in the oxidative burst was seen for the B strain only. When whole blood was preincubated for 30 min with TNF-alpha the increase in oxidative burst was significant for both meningococcal strains. TNF-alpha caused a significant increase in PMNL CD 11b/CD18 expression after 30 min of incubation at 37 degrees C. TNF-alpha added simultaneously with the bacteria induced a significant increase in PMNL CD11b/CD18 in both strains. Incubation with the B strain alone caused a low but significant increase in CD11b/CD18 expression, but the addition of TNF-alpha increased this expression to the same high level as incubation with TNF-alpha alone or the 29E strain alone. Only TNF-alpha and the 29E strain caused significant increases in CD14 expression. In conclusion, human PMNLs react differentially when stimulated with pathogenic and nonpathogenic N. meningitidis and the activating effect of TNF-alpha is variable depending on the bacteria involved.

Antigens, CD↗

Invasive disease due to Haemophilus influenzae type b during the first six years of general vaccination of Swedish children.

Since 1992-93 vaccination against Haemophilus influenzae type b (Hib) has been included in the general Swedish childhood vaccination programme. The aim of the present study is to describe the epidemiology, identify and describe vaccine failures and calculate vaccine effectiveness during the first 6 y after introduction of vaccination against Hib. Laboratory reports of blood and cerebrospinal isolates to the Swedish Institute for Infectious Disease Control were used as the source for identifying the patients. Additional information was subsequently obtained from physicians and parents of children who had developed the disease during the study period. Vaccine failures were identified and vaccine effectiveness calculated. During the study period, 152 cases of invasive H. influenzae were identified in the age group 0-14 y. During the 6-y period, 6 true vaccine failures, 6 apparent vaccine failures and 1 possible vaccine failure were found in nearly two million vaccinated child-years. The effectiveness of the Hib vaccination in the birth cohort of children 1993 to 1997 in Sweden was calculated to be 96.1% (95% confidence interval 94.2-97.5). The study supports earlier studies from several countries that conjugated Hib vaccination introduced in general childhood vaccination programs is effective and substantially decreases suffering from invasive Hib diseases.

Adolescent↗

Long-term persistence of a discotheque-associated invasive Neisseria meningitidis group C strain as proven by pulsed-field gel electrophoresis and porA gene sequencing.

A cluster of a Neisseria meningitidis serogroup C strain causing invasive disease was investigated. Five out of seven cases were associated with a particular discotheque. The strains were indistinguishable, as revealed by pulsed-field gel electrophoresis and sequencing of variable regions of the porA gene, but caused strikingly different clinical presentations during 5 months.

Adolescent↗

Epiglottitis in Sweden before and after introduction of vaccination against Haemophilus influenzae type b.

BACKGROUND: Acute epiglottitis is an important manifestation of invasive Haemophilus influenzae type b (Hib) infection. In 1992 and 1993 Hib vaccination was introduced in the general childhood vaccination program in Sweden. The aim of the present investigation was to study the impact of Hib vaccination on the diagnosis of epiglottitis in Sweden in children as well as adults. METHODS: A retrospective national population-based study on the incidence of epiglottitis in Sweden was performed for the 10-year period 1987 to 1996. The incidence calculations were based on figures from the national register of all patients treated at Swedish hospitals. The incidence (cases/100,000/year) for the prevaccination period 1987 to 1991 was compared with the incidence after Hib vaccination was introduced. RESULTS: In children a substantial decrease was found after introduction of large scale vaccination against Hib. Below 5 years of age the annual incidence decreased from 20.9 in 1987 to 0.9 in 1996. In adults a tendency toward a decrease in incidence was evident. CONCLUSIONS: Introduction of Hib vaccination in a general childhood program was followed not only by a >90% reduction in the incidence in the youngest age group but also by a reduction in the incidence in the older age groups and among adults.

Adult↗

Glycosphingolipid binding specificities of Neisseria meningitidis and Haemophilus influenzae: detection, isolation, and characterization of a binding-active glycosphingolipid from human oropharyngeal epithelium.

The glycosphingolipid binding specificities of Haemophilus influenzae and Neisseria meningitidis were investigated as to the binding of radiolabeled bacteria to glycosphingolipids on thin-layer chromatograms. Thereby, similar binding profiles, for the binding of the two bacteria to lactosylceramide, isoglobotriaosylceramide, gangliotriaosylceramide, gangliotetraosylceramide, lactotetraosylceramide, neolactotetraosylceramide, and sialylneolactohexaosylceramide, were obtained. On a closer view the binding preferences of the bacteria could be differentiated into three groups. The first specificity is recognition of lactosylceramide. The second specificity is binding to gangliotriaosylceramide and gangliotetraosylceramide, since conversion of the acetamido group of the N-acetylgalactosamine of gangliotriaosylceramide and gangliotetraosylceramide to an amine prevented the binding of the bacteria, and thus the binding to these two glycosphingolipids represents a separate specificity from lactosylceramide recognition. Preincubation of H. influenzae with neolactotetraose inhibited the binding to neolactotetraosylceramide, while the binding to lactosylceramide, gangliotetraosylceramide, or lactotetraosylceramide was unaffected. Thus, the third binding specificity is represented by neolactotetraosylceramide, and involves recognition of other neolacto series glycosphingolipids with linear N-acetyllactosamine chains, such as sialyl-neolactohexaosylceramide. The relevance of the detected binding specificities for adhesion to target cells was addressed as to the binding of the bacteria to glycosphingolipids from human granulocytes, epithelial cells of human nasopharyngeal tonsils and human plexus choroideus. Binding-active neolactotetraosylceramide was thereby detected in human granulocytes and the oropharyngeal epithelium.

Animals↗

Optimization of polymerase chain reaction for detection of HIV type 2 DNA.

The aim of this study was to increase the sensitivity of an earlier version of an HIV-2 nested PCR assay based on primers in the gag, pol, LTR, and env regions. The assay was first optimized with regard to concentrations of dNTP, MgCl2, and primers, using a method that allowed optimization of all three parameters in only two test runs. We then designed and optimized new primer sets in the LTR, gag, and gag/pol regions that were based on more isolates than were the former (old) primer sets. Samples from 57 HIV-2 antibody-positive individuals were tested with the four old primer sets as well as with the three new primer sets. Five primer sets from this run (new gag, new gag/pol, old LTR, old env, and new LTR) were then tested with 35 more samples, giving a total number of 92 tested samples from HIV-2-infected individuals. At initial testing of the 92 samples a combination of primer sets from two different regions yielded a sensitivity ranging from 93.5 to 98.9%. After repeated testing the sensitivity ranged from 96.7 to 100% for the different primer combinations. The specificity was 100% for all primer sets except old LTR, which had a specificity of 97%. In conclusion, it is possible to create a more sensitive PCR assay by optimizing the different PCR parameters as well as by including primer sets based on more isolates.

DNA Primers↗

[Policy program to minimize spread of infection. Prolonged cough may be a sign of tuberculosis].

In a worldwide epidemiological perspective, Sweden is well favoured with an annual tuberculosis incidence of approximately six cases per 100,000 of the population. Neither the impact of the HIV pandemic nor the occurrence of multiresistant strains of Mycobacterium tuberculosis has yet become a major problem in the care of tuberculosis patients in Sweden. Only a few per cent of HIV patients have developed tuberculosis, and during the period, 1991-94, only one per cent of M. tuberculosis isolates in Sweden were resistant to such antimycobacterials as isoniazid and rifampicin. However, the epidemiological situation in the neighbouring Baltic states is a matter for concern. Bovine tuberculosis has been eradicated in Sweden, the last case having been diagnosed in 1978. Although the reported efficacy of BCG (bacillus Calmette-Guérin) tuberculosis vaccine varies according to the population studied, protective rates of 70-85 per cent have been reported for Sweden and other west European countries. Re-vaccination of tuberculin-negative individuals has not been shown to yield added protection. The aim of a national programme for protection against tuberculosis is to preserve our favourable epidemiological situation by early detection of new cases, effective contact tracing, and BCG vaccination of children in population groups at risk. The primary means of achieving this is the education of health care personnel to retain tuberculosis as a differential diagnosis. Moreover, national guidelines for contact tracing must be duly observed, and immigrants from high prevalence areas need to be screened for tuberculosis. Registration of all cases of tuberculosis should be maintained at regional and national levels, and follow-up must be meticulous until a successful outcome of treatment is accomplished. Recommendations for dealing with tuberculosis should be made available and duly implemented at all hospitals caring for tuberculosis patients, in order to avoid nosocomial transmission. Although BCG vaccination at birth was formerly general in Sweden, since 1975 only children considered to be at risk have been vaccinated. Thus, non-vaccinated young adults are now entering the health care sector as students or employees, and should be offered BCG vaccination. Moreover, the epidemiological situation both in Sweden and in neighbouring countries needs to be monitored carefully in order that recommendations concerning BCG vaccination and other preventive measures can be modified if necessary.

Adult↗