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Biomedical subjects

J Waldenström

Publications and source records attributed to J Waldenström.

At least 19 recordsLinked to original sources
PubMed2004

Diversities and similarities in PFGE profiles of Campylobacter jejuni isolated from migrating birds and humans.

AIMS: To genetically sub-type Campylobacter jejuni strains isolated from migratory birds, and to compare these with clinical strains collected in the same area and corresponding time period, with the aim to increase our knowledge on sub-types occurring among wild birds and their possible impact on human disease. METHODS AND RESULTS: We sub-typed C. jejuni strains from migrating birds (n = 89) and humans (n = 47), using macrorestriction profiling by pulsed-field gel electrophoresis. Isolates from migrant birds often exhibited sub-types with higher levels of similarity to isolates from birds of the same species or feeding guild, than to isolates from other groups of birds. Likewise, could the vast majority of sub-types found among the migrant bird isolates not be identified among sub-types from human cases. Only two bird strains, one from a starling (Sturnus vulgaris) and one from a blackbird (Turdus merula), had sub-types that were similar to some of the human strain sub-types. CONCLUSIONS: Isolates from one bird species, or feeding guild, often exhibited high similarities, indicating a common transmission source for individuals, or an association between certain sub-types of C. jejuni and certain ecological guilds or phylogenetic groups of birds. Sub-types occurring among wild birds were in general distinctively different from those observed in patients. The two bird isolates that were similar to human strains were isolated from bird species that often live in close associations with human settlements. SIGNIFICANCE AND IMPACT OF STUDY: Wild birds have often been mentioned as a potential route for transmission of C. jejuni to humans. Our study demonstrates that strains isolated from birds most often are different from clinical strains, but that some strain similarities occur, notably in birds strongly associated with human activities.

Animals↗
PubMed2004

A new nested polymerase chain reaction method very efficient in detecting Plasmodium and Haemoproteus infections from avian blood.

Recently, several polymerase chain reaction (PCR)-based methods for detection and genetic identification of haemosporidian parasites in avian blood have been developed. Most of these have considerably higher sensitivity compared with traditional microscope-based examinations of blood smears. These new methods have already had a strong impact on several aspects of research on avian blood parasites. In this study, we present a new nested PCR approach, building on a previously published PCR method, which has significantly improved performance. We compare the new method with some existing assays and show, by sequence-based data, that the higher detection rate is mainly due to superior detection of Plasmodium spp. infections, which often are of low intensity and, therefore, hard to detect with other methods.

Animals↗
PubMed2002

Cross-species infection of blood parasites between resident and migratory songbirds in Africa.

We studied the phylogeny of avian haemosporidian parasites, Haemoproteus and Plasmodium, in a number of African resident and European migratory songbird species sampled during spring and autumn in northern Nigeria. The phylogeny of the parasites was constructed through sequencing part of their mitochondrial cytochrome b gene. We found eight parasite lineages, five Haemoproteus and three Plasmodium, infecting multiple host species. Thus, 44% of the 18 haemospiridian lineages found in this study were detected in more than one host species, indicating that host sharing is a more common feature than previously thought. Furthermore, one of the Plasmodium lineages infected species from different host families, Sylviidae and Ploceidae, expressing exceptionally large host range. We mapped transmission events, e.g. the occurrence of the parasite lineages in resident bird species in Europe or Africa, onto a phylogenetic tree. This yielded three clades, two Plasmodium and one Haemoproteus, in which transmission seems to occur solely in Africa. One Plasmodium clade showed European transmission, whereas the remaining two Haemoproteus clades contained mixes of lineages of African, European or unknown transmission. The mix of areas of transmission in several branches of the phylogenetic tree suggests that transmission of haemosporidian parasites to songbirds has arisen repeatedly in Africa and Europe. Blood parasites could be viewed as a cost of migration, as migratory species in several cases were infected with parasite lineages from African resident species. This cost of migration could have considerable impact on the evolution of migration and patterns of winter distribution in migrating birds.

Africa↗
PubMed2002

Campylobacter jejuni in black-headed gulls (Larus ridibundus): prevalence, genotypes, and influence on C. jejuni epidemiology.

Campylobacteriosis is a zoonotic disease in which birds have been suggested to play an important role as a reservoir. We investigated the prevalence of Campylobacter jejuni subsp. jejuni in black-headed gulls (Larus ridibundus) in southern Sweden with the aim of examining the nature of C. jejuni infection in this bird species. Birds were sampled in four sampling series each year during 1999 (n = 419) and 2000 (n = 365). Longitudinally sampled C. jejuni isolates from individual gulls were subjected to macrorestriction profiling (MRP) by pulsed-field gel electrophoresis to investigate the genotypical stability during the natural course of infection. Furthermore, a subset (n = 76) of black-headed gull isolates was compared to isolates from broiler chickens (n = 38) and humans (n = 56) originating from the same geographic area. We found a pronounced seasonal variation in C. jejuni carriage, with the highest rates found in late autumn. MRP similarities were higher between isolates of human and broiler chicken origin, than between those of wild bird origin and either of the other two hosts. However, identical MRPs were found in two gull isolates and one human isolate after digestion with two restriction enzymes, strongly indicating that they may have been colonized by the same clone of C. jejuni. The MRPs most prevalent in gull isolates did not occur among isolates from humans and broiler chickens, suggesting the existence of a subpopulation of C. jejuni adapted to species-specific colonization or environmental survival.

Animals↗
PubMed2001

Development and evaluation of assays for the determination of total and pancreatic amylase at 37 degrees C according to the principle recommended by the IFCC.

OBJECTIVES: The aim of our study was a) to optimize assays for measurement of total (T-) and pancreatic (P-)amylase at 37 degrees C based on the principle recommended by the IFCC at 30 degrees C, b) to evaluate the analytical performance of these assays in a multicentric study and c) to establish reference intervals for serum and urine for either method. METHODS: Optimized conditions for 37 degrees C were elaborated with regard to substrate concentration, pH, inorganic additives and glucosidase activity. The cleavage pattern of the EPS substrate was studied by HPLC. Liquid ready-to-use reagents for T- and P-amylase were provided to six European laboratories. RESULTS: The assays showed good performance characteristics (median intraassay CVs 1.0% for T- and 1.3% for P-amylase, median interassay CVs 3.0% for either assay, dynamic range 15-fold URL for T- and 30-fold for P-amylase), high correlation with the previous EPS methods (r > 0.996, slope 0.43, intercept < 5 U/L) in serum, heparin plasma and urine and good analytical specificity of the P-amylase assay (residual S-amylase activity 2.4%). Serum reference ranges were found to be 28 to 100 U/L for T- and 13 to 53 U/L for P-amylase (n = 775); URLs in urine were estimated as 490 U/L or 280 U/g creatinine for males and 450 U/L or 380 U/g creatinine for females with total amylase. CONCLUSION: We believe that these assays based on the 30 degrees C IFCC recommendation represent a further improvement in amylase methodology at 37 degrees C and merit broad application in clinical routine.

Amylases↗
PubMed1999

Does the uncertainty of commonly performed glucose measurements allow identification of individuals at high risk for diabetes?

Revised recommendations for diagnosis of diabetes introduce the intermediary risk group of impaired fasting glucose (IFG), defined as individuals with a fasting blood-glucose concentration between 5.6 and 6.0 mmol/l. We apply the concept of uncertainty to identifiable steps of sampling and measuring blood-glucose. Since many instruments in primary health care measure plasma-glucose and report results as blood-glucose and vice versa, factors affecting the transformation are also considered. The study identifies the measurement procedure as the major source of uncertainty, closely followed by preanalytical sources. The estimated uncertainties indicate that the presently available procedures do not allow identification of IFG by a single investigation. The approach to establish an uncertainty budget can be used to evaluate the clinical usefulness of measurements.

Blood Glucose↗
PubMed1995

Successful intravenous immunoglobulin therapy for severe and persistent astrovirus gastroenteritis after fludarabine treatment in a patient with Waldenström's macroglobulinemia.

A 78-year-old male with Waldenström's macroglobulinemia was after 23 years of conservative treatment given fludarabine phosphate in 1993 because of disease progression. Three weeks after the third fludarabine course he presented with a 5-day-history of watery diarrhoea, nausea and vomiting. Stool cultures were negative but a semiquantitative electron microscopy method demonstrated massive amounts of astrovirus (> 10(14) particles/ml). Symptomatic treatment was given but since his condition deteriorated, high-dose intravenous immunoglobulin (IvIg) treatment, 0.4 g/kg for four days was initiated. Within twenty-four hours all symptoms disappeared and the patient was discharged after a few days. A stool sample collected after two weeks demonstrated 10(7) particles/ml and after four weeks no astrovirus could be detected. The association between fludarabine and this opportunistic infection and the potential role of high dose IvIg treatment are discussed.

Aged↗
PubMed1995

Waldenström's macroglobulinemia with the AML/MDS-associated t(1;3)(p36;q21).

Two unusual, and perhaps causally related, clinical and cytogenetic features in a patient with Waldenström's macroglobulinemia are presented. Firstly, during the progression of the primary macroglobulinemia bone destruction and hypercalcemia occurred. Secondly, a t(1;3)(p36;q21) was found as the sole clonal chromosomal abnormality. This translocation is characteristic of acute myeloid leukemia (AML) and myelodysplastic syndromes with a high propensity for progressing to AML. The t(1;3) has previously never been reported in a lymphoproliferative disorder. Since the abnormality is associated with acute transformation of cells of the myelopoietic lineages, it is possible that the t(1;3), found in cells of lymphoid origin in the present case, not only induced the neoplastic process as such but also brought about the unusually malignant tumor progression.

Chromosomes, Human, Pair 1↗
PubMed1990

Fasting serum insulin concentration and early insulin response as risk determinants for developing diabetes.

Among a cohort of 348 women aged 50 on entering a 12-year prospective study, the incidence of diabetes was increased (17.1%) during follow-up in those who initially had fasting glucose concentration above the upper quintile, a fasting serum insulin concentration above the upper quintile (14.9%), a disappearance rate of glucose below the lowest quintile in an IV glucose tolerance test (12.7%), or early insulin response below the lowest quintile (17.1%). The incidence in all women was 4.9%. By multivariate analysis, the highest risk was for high fasting serum insulin concentration. Obesity and treatment with antihypertensive drugs further increased the risk. An initial low early insulin response was not however a prerequisite for the development of manifest diabetes. Determination of fasting insulin concentration, especially in overweight hypertensive subjects, is of value in order to find out which subjects are at high risk of developing diabetes.

Biomarkers↗
PubMed1990

Protective effects of pretreatment with superoxide dismutase, catalase and oxypurinol on tubular damage caused by transient ischaemia.

The effect of 60 min of ischaemia on glomerular and tubular functions (osmolar clearance, fractional Na+ excretion, K+ clearance, concentrating ability) after different periods of time was studied in New Zealand White rabbits. Pronounced changes in both glomerular and tubular functions were observed immediately on reperfusion and after 48 h. One week after ischaemia the functions appeared to be normalized. Mannitol is routinely used in clinical kidney transplantation due to its hyperosmolar effects and its ability to scavenge the hydroxyl radical. In the present study the possible additive protective effect against ischaemia-reperfusion damage of a combined pretreatment with mannitol and oxygen free radical scavengers or mannitol and a xanthine oxidase inhibitor was examined. Oxypurinol was chosen as the xanthine oxidase inhibitor due to its direct inhibitory effect. Concerning glomerular function, no protective effect of the combined pretreatment compared with mannitol alone was observed. However, concerning the tubular function tests combined pretreatment with either mannitol-superoxide dismutase-catalase or mannitol-oxypurinol turned out to be superior compared with that of mannitol alone.

Animals↗
PubMed1988

Infarct size limitation after early intervention with metoprolol in the MIAMI Trial.

One of the secondary objectives of the MIAMI Trial which evaluated the role of the beta-1-selective blocker metoprolol in suspected acute myocardial infarction was to further assess whether early intervention with beta-blockade can limit infarct size. A total of 5,778 patients from 104 worldwide centres were randomized into the trial. Various enzymes such as aspartate aminotransferase (ASAT), creatine kinase (CK), CK MB, CK B, lactate dehydrogenase (LD) and LD isoenzyme I were analysed. All enzymes were used according to the clinical routine of the respective hospital, except ASAT which was analysed once daily for 3 days in the majority of cases and LD I which was analysed every 12 h for 72 h in a subsample. A consistent observation was the lower serum enzyme activity among patients receiving metoprolol and randomized early after onset of symptoms, whereas no difference between metoprolol and placebo was observed in patients treated later in the course. The results of the MIAMI Trial support previous observations that early institution of metoprolol therapy limits infarct size, as indicated by the maximum serum enzyme activity.

Adolescent↗