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Biomedical subjects

A B Andersen

Publications and source records attributed to A B Andersen.

At least 19 recordsLinked to original sources
PubMed2006

Elevated levels of soluble urokinase receptor in serum from mycobacteria infected patients: still looking for a marker of treatment efficacy.

In search for a serological marker, which may be used to monitor treatment efficacy in patients with extra-pulmonary mycobacterial infections, serum samples were collected prospectively from patients during a 6-months treatment period. The levels of soluble urokinase-type plasminogen activator receptor (suPAR) and soluble tumour necrosis factor receptor II (sTNFrII) were measured and compared with erythrocyte sedimentation rate (SR) and C-reactive protein levels (CRP). sTNFrII levels were elevated at the time of diagnosis and declined in parallel with traditional inflammation markers (SR and CRP). suPAR levels were elevated to more than double (median 7.7 ng/ml, range 5.6-25.8) compared to levels previously reported for patients with pulmonary tuberculosis. The serum suPAR levels however remained high during the entire treatment period. This may reflect that significant inflammatory activity is continuing for more than 6 months in patients with extrapulmonary mycobacterial infections, despite adequate anti-tuberculosis treatment.

Adult↗
PubMed2005

The long-term pharmacokinetics and safety of adding low-dose ritonavir to a nelfinavir 1,250 mg twice-daily regimen in HIV-infected patients.

OBJECTIVES: To evaluate the long-term pharmacokinetics and safety of adding ritonavir 100 mg twice-daily to a nelfinavir 1250 mg twice-daily regimen in HIV-infected patients. METHODS: This was a prospective, randomized, open-label, controlled 24-week study. Sixteen patients receiving a nelfinavir 1250 mg twice-daily regimen with plasma viral load <1000 HIV-1 RNA copies/mL were randomized to continue treatment or to have ritonavir 100 mg twice-daily added. Safety, including fasting lipid levels, was evaluated at weeks 4, 12 and 24. Patients who were randomized to have ritonavir added (n=9) participated in three 12-h pharmacokinetic evaluations at baseline, week 4 and week 24. RESULTS: Increases in median nelfinavir steady-state plasma concentrations at 12 h (C(12)) from 512 to 773 ng/mL [median difference 450 ng/mL; 95% confidence interval (CI) 116--1510 ng/mL] and in median active nelfinavir metabolite M 8 C(12) from 107 to 603 ng/mL (median difference 545 ng/mL; 95% CI 370--891) were seen after the addition of low-dose ritonavir (baseline to week 24). There were no differences between the nelfinavir or M 8 pharmacokinetic parameters at weeks 4 and 24. No significant changes or differences in the concentration of fasting total cholesterol, low-density lipoprotein (LDL) cholesterol or total triglycerides or in the occurrence of adverse events were observed within or between the two groups. CONCLUSIONS: Nelfinavir and especially M 8 concentrations are increased when low-dose ritonavir is added to a nelfinavir-containing regimen. The combination seems to be safe and the nelfinavir/ritonavir regimen could be an option in patients with low nelfinavir+M 8 concentrations.

Adult↗
PubMed2004

Pharmacokinetic interaction between rifampin and the combination of indinavir and low-dose ritonavir in HIV-infected patients.

Rifampin is an important drug in the treatment of tuberculosis, but administration of rifampin in combination with protease inhibitors is complicated because of drug-drug interactions. A prospective, controlled, multiple-dose study involving 6 HIV-infected patients receiving a combination of indinavir (800 mg) and ritonavir (100 mg) twice a day was performed to evaluate whether the inducing effect of rifampin on the drug-metabolizing enzyme cytochrome P450 (CYP) 3A4 could be overcome by the inhibitory effect of ritonavir. Pharmacokinetic evaluations of steady-state concentrations of indinavir and ritonavir were performed before and after administration of rifampin (300 mg every day for 4 days). An 87% reduction (from 837 to 112 ng/mL) in median indinavir and a 94% reduction (from 431 to 27 ng/mL) in median ritonavir concentrations were seen 12 h after the last dose of rifampin was administered (P=.031). These results strongly indicate that the administration of rifampin with a combination of indinavir (800 mg) and ritonavir (100 mg) could lead to subtherapeutic concentrations of indinavir.

Adult↗
PubMed2004

A dominant Mycobacterium tuberculosis strain emerging in Denmark.

SETTING: Denmark, a high-income country with a low prevalence of tuberculosis. OBJECTIVE AND DESIGN: Molecular epidemiological studies of Mycobacterium tuberculosis strains are conducted worldwide, and distinct strains have been associated with large outbreaks of tuberculosis. This is the first systematic population-based search for distinct strains of M. tuberculosis in Denmark among 4102 strains DNA fingerprinted nationwide from 1992 to 2001. RESULTS: A specific strain of M. tuberculosis has emerged rapidly in Denmark: in 1992, the Danish Cluster 2 strain accounted for 5.8% of all culture-positive Danish-born cases, increasing to 29.0% in 2001. The Cluster 2 cases were on average younger (41.8 vs. 51.4 years), more likely to be male (81.4% vs. 64.1%), and more likely to have pulmonary involvement only (90.3% vs. 64.6%) than other Danish-born cases. During the first 4 observation years, they were mainly found in the capital city, Copenhagen, but were later increasingly observed in the provinces. CONCLUSION: The reasons for the increasing dominance and change in geographical distribution of Cluster 2 strains in Denmark is unknown, but may be partly explained by the fact that Cluster 2 is associated with younger males with pulmonary disease manifestation. We consider it as an outbreak and believe the situation requires increased focus on early tuberculosis diagnosis and control of transmission in Denmark.

Adult↗
PubMed2001

Risk of Mycobacterium tuberculosis transmission in a low-incidence country due to immigration from high-incidence areas.

Does immigration from a high-prevalence area contribute to an increased risk of tuberculosis in a low-incidence country? The tuberculosis incidence in Somalia is among the highest ever registered. Due to civil war and starvation, nearly half of all Somalis have been forced from their homes, causing significant migration to low-incidence countries. In Denmark, two-thirds of all tuberculosis patients are immigrants, half from Somalia. To determine the magnitude of Mycobacterium tuberculosis transmission between Somalis and Danes, we analyzed DNA fingerprint patterns of isolates collected in Denmark from 1992 to 1999, comprising >97% of all culture-positive patients (n = 3,320). Of these, 763 were Somalian immigrants, 55.2% of whom shared identical DNA fingerprint patterns; 74.9% of these were most likely infected before their arrival in Denmark, 23.3% were most likely infected in Denmark by other Somalis, and 1.8% were most likely infected by Danes. In the same period, only 0.9% of all Danish tuberculosis patients were most likely infected by Somalis. The Somalian immigrants in Denmark could be distributed into 35 different clusters with possible active transmission, of which 18 were retrieved among Somalis in the Netherlands. This indicated the existence of some internationally predominant Somalian strains causing clustering less likely to represent recent transmission. In conclusion, M. tuberculosis transmission among Somalis in Denmark is limited, and transmission between Somalis and Danes is nearly nonexistent. The higher transmission rates between nationalities found in the Netherlands do not apply to the situation in Denmark and not necessarily elsewhere, since many different factors may influence the magnitude of active transmission.

Adolescent↗
PubMed2000

A prospective evaluation of the clinical value of nation-wide DNA fingerprinting of tuberculosis isolates in Denmark.

SETTING: Denmark, a country with a low incidence of tuberculosis (TB). OBJECTIVE: To evaluate the value of the nation-wide DNA fingerprinting of Mycobacterium tuberculosis isolates performed in Denmark since 1992. DESIGN: Prospective study of consecutive patients with culture-verified TB from five large TB Departments in Denmark during a 7-month period in 1998. Results of IS6110 RFLP and spoligotyping were compared to those in the nation-wide Danish DNA-fingerprint database which covers approximately 95% of all culture-verified TB cases from 1992 onwards. Questionnaires asking about contact tracing and epidemiological links were sent to the patients' treating physicians. RESULTS: Of the 177 patients included in the study, 57 were Danes, one was from Iceland, 111 were immigrants, and eight were from Greenland. Responses to the questionnaires were obtained from 163 patients (92%). Four cases of unsuspected transmission were detected: one of nosocomial spread of TB, one of occupational acquisition of TB and two of transmission in an international school, leading to further contact tracing among 75 schoolchildren. These four cases were all the result of short-term contacts. In 22 cases, contact with one or more TB patient(s) was reported. In six of these, the DNA-fingerprint result revealed that the presumed contact could not be the source of infection, even though in two of the cases the known TB contact was from the household. CONCLUSION: Nation-wide DNA fingerprinting of TB isolates provides information that could not have been obtained otherwise, and contribute to the understanding of TB transmission in Danish society. In some cases the results lead to further contact tracing. Short-term contact can apparently result in transmission of TB.

Adult↗
PubMed1999

Presence and dehydration of ikaite, calcium carbonate hexahydrate, in frozen shrimp shell.

Ikaite, calcium carbonate hexahydrate, has by means of X-ray diffraction analyses of frozen samples been identified as the mineral component of the white spots formed in the shell of frozen shrimp during storage. When the shrimp thaw and the shell material is dried and kept at room temperature, ikaite rapidly transforms into a mixture of anhydrous calcium carbonate forms. X-ray diffraction analyses and Raman spectra of synthetic ikaite as well as the dehydration product confirm the assignments, and the rate constant for dehydration is approximately 7 x 10(-)(4) s(-)(1) at ambient temperature. Differential scanning calorimetry showed that dehydration of synthetic ikaite is an entropy-driven, athermal process and confirms that a single first-order reaction is rate-determining. Ikaite is found to be stable in aqueous solution at temperatures below 5 degrees C and in the shell of frozen shrimps but decomposes on thawing to form anhydrous calcium carbonates.

Animals↗
PubMed1999

Epidemiology of tuberculosis in HIV-infected patients in Denmark.

Denmark is an area of low incidence of HIV and tuberculosis (TB). The number of newly reported cases of HIV has been stable during the 1990s, whereas the number of TB cases has doubled in Denmark in the past decade, mainly due to immigration. However, among native Danes the incidence of TB has increased in the younger age groups, indicating more newly infected persons. This study was performed in order to assess the impact of the HIV epidemic and immigration on TB incidence among native Danes. The study was also designed to reveal transmission patterns of TB among HIV-positive patients. Data from HIV-TB co-infected patients identified in the national registers of TB and AIDS from 1992-95 were collected retrospectively from medical records. Restriction fragment length polymorphism (RFLP) analyses of TB isolates from co-infected patients were compared with all patterns registered in the nationwide Danish RFLP database (approximately 1,700 patients). Sixty-seven co-infected patients were identified, 26 Danes and 41 immigrants, representing only 4% of all TB cases during the study period. Danish co-infected patients were part of a cluster, i.e. they had a RFLP-pattern identical to a pattern in the national RFLP database, more often than immigrants (83% vs. 45%, p < 0.005). In only 2 cases were co-infected Danes and immigrants part of the same cluster. Danish HIV-TB co-infected patients were more often intravenous drug users than were co-infected immigrants (p < 0.0005). In conclusion, we found no evidence to suggest that the increase in TB incidence among young Danes was caused by the HIV-epidemic or transmission from immigrants. TB among HIV-positive Danes is most often due to recent infection. The patients often belong to a subpopulation living in Copenhagen characterized by intravenous drug use.

AIDS-Related Opportunistic Infections↗
PubMed1999

Stability of insertion sequence IS1245, a marker for differentiation of Mycobacterium avium strains.

Recently a novel insertion element, IS1245, has been described and suggested for use as a probe in restriction fragment length polymorphism studies of Mycobacterium avium strains. An important issue in this context is the stability of the insertion element. We analyzed single colonies of M. avium cultures and found frequent small one- to two-band changes. However, following repeated in vitro passages over 1 year, similar one- to two-band changes were observed in the IS1245 patterns of only six M. avium strains investigated.

AIDS-Related Opportunistic Infections↗
PubMed1999

Typing of clinical Mycobacterium avium complex strains cultured during a 2-year period in Denmark by using IS1245.

In the present study restriction fragment length polymorphism analyses with the recently described insertion sequence IS1245 as a probe was performed with clinical Mycobacterium avium complex strains cultured in Denmark during a 2-year period. The overall aim of the study was to disclose potential routes of transmission of these microorganisms. As a first step, the genetic diversity among isolates from AIDS patients and non-human immunodeficiency virus (HIV)-infected patients was described. In addition, a number of isolates from nonhuman sources cultured during the same period were analyzed and compared to the human isolates. A total of 203 isolates from AIDS patients (n = 90), non-HIV-infected patients (n = 91), and nonhuman sources (n = 22) were analyzed. The presence of IS1245 was restricted to Mycobacterium avium subsp. avium isolates. The majority of human isolates had large numbers of IS1245 copies, while nonhuman isolates could be divided into a high-copy-number group and a low-copy-number group. Groups of identical strains were found to be geographically widespread, comprising strains from AIDS patients as well as strains from non-HIV-infected patients. Samples of peat (to be used as potting soil) and veterinary samples were found to contain viable M. avium isolates belonging to genotypes also found in humans.

AIDS-Related Opportunistic Infections↗
PubMed1999

Usefulness of spoligotyping To discriminate IS6110 low-copy-number Mycobacterium tuberculosis complex strains cultured in Denmark.

Mycobacterium tuberculosis complex strains cultured in Denmark have been analyzed by IS6110 restriction fragment length polymorphism (RFLP) on a routine basis from 1992 and onwards. Due to the influx of immigrants with tuberculosis, the number of strains harboring only one to five copies of IS6110 has increased steadily. Since the discriminatory power of IS6110 fingerprinting for such strains is poor, we have performed additional genotyping of all low-copy-number strains by the recently described PCR-based method known as spoligotyping. A total of 311 clinical strains were typed: 14 Mycobacterium bovis BCG, 48 M. bovis, and 249 M. tuberculosis strains. Spoligotyping correctly differentiated M. bovis and M. bovis BCG from M. tuberculosis strains, but it did not differentiate M. bovis from M. bovis BCG. All M. bovis BCG strains exhibited identical spoligotype patterns. The discriminatory power of spoligotyping of low-copy-number M. tuberculosis strains was higher than that of IS6110 fingerprinting. Based on RFLP typing solely, 83% of the low-copy-number M. tuberculosis strains were found to form part of a cluster, and 75% were found to form a cluster on the basis of spoligotyping. When the two techniques were combined, the amount of clustering decreased to 55%. The combination of these two techniques might be valuable in studying the epidemiology of M. tuberculosis strains harboring few copies of the IS6110 element.

DNA Fingerprinting↗
PubMed1999

Hepatic actinomycosis. A case report.

A case of hepatic actinomycosis contracted one year after removal of an intrauterine device during ongoing Actinomyces cervicitis is reported. During active disease, lymphocytes from the apparently fully immunocompetent patient were able to proliferate but not to produce the proinflammatory lymphokine gamma-interferon in response to Actinomyces antigen. This ability was only partly restored during antibiotic therapy.

Actinomycosis↗
PubMed1998

MPB70 and MPB83 as indicators of protein localization in mycobacterial cells.

Culture fluids after growth of Mycobacterium bovis BCG on Sauton medium contain actively secreted proteins and proteins released by bacterial lysis. BCG culture fluids and sonicates of Mycobacterium tuberculosis and Mycobacterium paratuberculosis were tested after separation by gel filtration and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The localization of marker proteins was determined by enzyme-linked immunosorbent assay and Western blotting with selected monoclonal antibodies of known specificities. Soluble secreted proteins (MPB64 and proteins of the antigen 85 complex) and three heat shock proteins (DnaK, GroEL, and GroES) were recovered in a single peak after gel filtration, indicating their occurrence as a free monomer in the culture fluid and cytosol, respectively. Other constituents eluted in two distinct peaks during gel filtration. The first peak corresponded to the void volume, indicating complex formation between several proteins or attachment to lipids in the surface layer or the cytoplasmic membrane; the second peak corresponded to the expected monomer size indicated by SDS-PAGE under conditions that separate proteins from each other during sample preparation. The two-peak group contained constituents with known lipid contents, the 19- and 38-kDa lipoproteins and lipoarabinomannan. The 26-kDa form of MPB83 behaved similarly. After extraction with Triton X-114, these constituents entered into the detergent phase, confirming the lipoprotein nature of 26-kDa MPB83. The MPB83 molecule was shown to be available on the surface of BCG Tokyo bacilli for reaction with monoclonal antibody MBS43 by flow cytometry.

Antibodies, Monoclonal↗
PubMed1998

Results from 5 years of nationwide DNA fingerprinting of Mycobacterium tuberculosis complex isolates in a country with a low incidence of M. tuberculosis infection.

Results from DNA fingerprint analyses of Mycobacterium tuberculosis complex isolates from tuberculosis (TB) patients diagnosed during 5 years in Denmark are presented. The lack of success in eradicating TB in this low-incidence country may be explained by an unrecognized high frequency of active TB transmission (57%) among native Danes. Only two strains of M. tuberculosis are responsible for 40% of all clustered cases of TB among Danes.

Adolescent↗