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Biomedical subjects

J S Jensen

Publications and source records attributed to J S Jensen.

At least 19 recordsLinked to original sources
PubMed1995

Aspects of haemostatic function in healthy subjects with microalbuminuria--a potential atherosclerotic risk factor.

Microalbuminuria, i.e., slightly elevated urinary albumin excretion rate (UAER), notifies increased risk for atherosclerotic disease and may reflect an early generalized vascular abnormality in healthy subjects. This study was designed in order to examine whether such abnormality is associated with a shift of the haemostatic balance in prothrombotic direction. The following haemostatic factors were measured in two representative groups of clinically healthy subjects, 28 with microalbuminuria (UAER of 6.6-150 micrograms/min) and 60 age- and sex-matched controls with normoalbuminuria (UAER < 6.6 micrograms/min): Coagulation factors: blood platelet count and mean volume, plasma Factor VII antigen concentration and coagulant activity, and plasma concentrations of prothrombin fragment 1 + 2, thrombin-antithrombin III complexes, fibrinogen, and fibrinopeptide A; fibrinolytic and endothelial factors: plasma concentrations of tissue plasminogen activator antigen and plasminogen activator inhibitor type 1 antigen; and endothelial factor: plasma von Willebrand factor antigen concentration. The fibrinolytic and endothelial factors were measured both before and after 10 minutes of venous occlusion of the arm. None of the haemostatic factors were significantly altered in the microalbuminuric group. Plasma fibrinogen concentration tended to be elevated but not statistically significant ((mean (95% C.I.) 7.8 (7.2-8.3) vs. 7.2 (6.9-7.5) mumol/l; p < 0.1). Neither did any of the haemostatic factors correlate with UAER in regression analyses. It is concluded that the haemostatic balance is unaltered in healthy subjects with microalbuminuria. It is unlikely that a prothrombotic state is present as an intermedial factor early in a causal chain between microalbuminuria and atherosclerotic vascular disease.

Adult↗
PubMed1995

Atherosclerotic risk factors are increased in clinically healthy subjects with microalbuminuria.

Increased morbidity and mortality from atherosclerotic vascular disease were observed in subjects with slightly elevated urinary albumin excretion rate (UAER), known as microalbuminuria. Therefore, the association between microalbuminuria and established atherogenic risk factors was studied in clinically healthy subjects. All healthy 40-65 year-old participants with microalbuminuria, examined within the first 21 months of The Copenhagen City Heart Study, were invited, and 28 were studied. An age- and sex-matched group of 60 randomly chosen subjects with normoalbuminuria served as control. Microalbuminuria was defined as a UAER of 6.6-150 micrograms/min, and normoalbuminuria as a UAER < or = 6.6 micrograms/min. In the microalbuminuric group, systolic and diastolic blood pressures were both elevated (mean (95% C.I.) 128 (123-134) vs. 119 (116-122) mmHg; P = 0.005, and 75 (71-78) vs. 69 (67-71) mmHg; P = 0.008, respectively), and serum apolipoprotein (apo) A-1 concentration was lower (1.30 (1.20-1.37) vs. 1.42 (1.36-1.47) milligrams; P = 0.02) in comparison with the normoalbuminuric group. Furthermore, serum HDL-cholesterol concentration tended to be lower, whereas body weight, body mass index and fasting serum insulin concentration were slightly elevated in the microalbuminuric group but not statistically significant. It is concluded that microalbuminuria in clinically healthy subjects is associated with increased levels of atherogenic risk factors. This may contribute to the increased vascular morbidity and mortality observed in these individuals.

Age Factors↗
PubMed1995

Innovations in acrylic bone cement and application equipment.

A new bone cement was developed with the purpose of reducing the adverse biological effects during cementation of implants. This bone cement is characterized by lower exotherm, low release of monomer, low residual content of monomer, and retained physical properties. The essential innovation was substitution of half of the methylmethacrylate (MMA) in the monomer with long chain, high molecular weight, less volatile, and less soluble methacrylates (n-decylmethacrylate, isobornyl-methacrylate), as well as alteration of the accelerator system to a mix of dihydroxypropyl-p-toluidine and N,N-dimethyl-p-toluidine. The powder contains butylmethacrylate-MMA copolymers. These measures lower the glass-transition temperature, and permit more complete mixing in an integrated package, mixing, and delivery system consisting of a vacuum packed, double chamber pouch. The porosity was reduced to about 2% and the largest voids measured 0.1 mm. The polymerization exotherm was reduced to 58 degrees C. The compressive strength was 82 MPa, the four-point bending strength 55 MPa, the flexural modulus 2.24 GPa, the tensile strength 32 MPa, and the shear strength 36 MPa. The fracture toughness was 0.89 MPa square root of cm. These mechanical properties together with the fatigue life were on level with manually mixed, conventional PMMA bone cements.

Biocompatible Materials↗
PubMed1995

Nosocomial legionellosis in three heart-lung transplant patients: case reports and environmental observations.

Organ transplant recipients are at high risk of contracting Legionnaires' disease in a hospital environment contaminated with legionellae. This study describes the first cases of culture-verified Legionella infections with an established link to potable hospital water in Denmark; three patients operated on at the Cardiopulmonary Transplant Unit, Rigshospitalet, Copenhagen, became infected with legionellae. Environmental and clinical isolates of Legionella pneumophila serogroups 1 and 6 were investigated by restriction enzyme analysis and ribotyping. An ice machine located in the kitchen of the intensive care unit was implicated as a source of infection in two of the three cases.

Cross Infection↗
PubMed1995

Microalbuminuria reflects a generalized transvascular albumin leakiness in clinically healthy subjects.

1. In epidemiological studies microalbuminuria, i.e. slightly elevated urinary albumin excretion rate, predicts increased atherosclerotic vascular morbidity and mortality. This study aimed to test the hypothesis that microalbuminuria in clinically healthy subjects is associated with a systemic transvascular albumin leakiness. In animal experiments the outflux of albumin and lipids to the arterial wall are highly correlated, and both are elevated in atherosclerosis. 2. All participants were recruited at random from a population-based epidemiological study, where the upper decile of urinary albumin excretion rate was 6.6 micrograms/min. Twenty-seven patients with persistent microalbuminuria (urinary albumin excretion rate 6.6-150 micrograms/min), and 56 age- and sex-matched control subjects with persistent normoalbuminuria (UAER < or = 6.6 micrograms/min) were studied. 3. The systemic transvascular albumin leakage was measured as the fractional disappearance rate of 125I-labelled albumin from the total plasma compartment in 1 h after intravenous injection. 4. The fractional disappearance rate of albumin from the plasma compartment was higher in the microalbuminuric than in the normoalbuminuric group [5.8 (95% confidence interval 5.3-6.2; n = 27) versus 5.0 (4.6-5.5; n = 56)%/h, P < 0.05]. The positive correlation between urinary albumin excretion rate on continuous scale (logarithmically transformed) and the fractional disappearance rate of albumin from the plasma compartment [slope 0.4 (95% confidence interval 0.1-0.7; n = 83), r = 0.29, P < 0.005] was independent of age, sex, smoking status, blood pressure, body size, plasma volume, plasma albumin concentration and concentrations of blood glucose, serum insulin and serum lipids. 5. In conclusion, microalbuminuria is an independent marker of systemic transvascular albumin leakiness in clinically healthy subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Albuminuria↗
PubMed1995

Reduced glomerular size- and charge-selectivity in clinically healthy individuals with microalbuminuria.

The pathophysiologic mechanism behind microalbuminuria, a potential atherosclerotic risk factor, was explored by measuring fractional clearances of four endogenous plasma proteins of different size and electric charge (albumin, beta 2-microglobulin, immunoglobulin G, and immunoglobulin G4). Twenty-eight clinically healthy individuals with microalbuminuria, defined as a urinary albumin excretion of 6.6-150 micrograms min-1, and 60 matched control subjects were studied. Fractional immunoglobulin G clearance was higher (geometric means (95% confidence intervals)) 3.0 (2.3-3.9) x 10(-6), n = 28, vs. 2.1 (1.8-2.4) x 10(-6), n = 60; P = 0.02), whereas the ratio immunoglobulin G clearance/immunoglobulin G4 clearance was lower (geometric means (95% confidence intervals)) 1.8 (1.4-2.2), n = 28, vs. 2.3 (2.0-2.5), n = 60; P = 0.03) in microalbuminuric than in normoalbuminuric individuals. Fractional beta 2-microglobulin clearance was similar in the two groups. Since total IgG and the IgG4 subclass are of similar size and configuration but electrically neutral and negative, respectively; these findings indicate that microalbuminuria is associated with decreased size- and charge-selectivity of the glomerular vessel wall. Hypothetically, such alterations may reflect generalized vascular abnormalities linking microalbuminuria to atherogenesis.

Adult↗
PubMed1995

Serum sialic acid concentration is elevated in IDDM especially in early diabetic nephropathy.

OBJECTIVES: Elevated serum sialic acid concentration is a strong predictor of cardiovascular mortality in non-diabetic subjects. Because patients with insulin-dependent diabetes mellitus (IDDM) and albuminuria have a highly increased cardiovascular morbidity and mortality, we hypothesized that IDDM patients with albuminuria would have an increased concentration of serum sialic acid. DESIGN: Cross-sectional study. SETTING: Outpatient clinic at Steno Diabetes Centre, Gentofte, Denmark. SUBJECTS: Twenty-six non-diabetic controls and 74 IDDM patients with normoalbuminuria (urinary albumin excretion [UAE] < 30 mg 24 h-1; n = 37), incipient nephropathy (UAE 30-300 mg 24 h-1; n = 20) and clinical nephropathy (UAE > 300 mg 24 h-1; n = 17), matched for sex, age and body mass index (BMI). MAIN OUTCOME MEASURES: Serum sialic acid concentration, concurrent fasting blood glucose, glycated haemoglobin (HbA1c), serum creatinine, plasma fibrinogen and erythrocyte sedimentation rate. RESULTS: Normoalbuminuric patients had a higher serum sialic acid concentration (mmol L-1) than non-diabetic controls (1.83 +/- 0.24 vs. 1.67 +/- 0.26; P < 0.02). Serum sialic acid concentration was further increased in patients with incipient nephropathy (2.02 +/- 0.37; P < 0.03) and in patients with clinical nephropathy (2.13 +/- 0.33; P < 0.002) compared with normoalbuminuric IDDM patients. Serum sialic acid correlated strongly with plasma fibrinogen (r = 0.78; P < 0.0001) and erythrocyte sedimentation rate (r = 0.62; P < 0.0001). In a multiple regression analysis including UAE, retinopathy status, fasting blood glucose, HbA1c, mean blood pressure, serum creatinine, age, BMI, duration and smoking. UAE and fasting blood glucose were the independent variables which correlated significantly with serum sialic acid concentration (P < 0.0001 and P < 0.05, respectively). CONCLUSION: Serum sialic acid is elevated in IDDM especially in albuminuric patients. Whether elevated serum sialic acid is predictive for early diabetic nephropathy and cardiovascular disease in IDDM has to be shown in the future.

Adult↗
PubMed1995

Renal and systemic transvascular albumin leakage in severe atherosclerosis.

Microalbuminuria was recently proposed as a novel atherogenic risk factor. The pathophysiological link between microalbuminuria and atherosclerosis may be mediated through an increased generalized transvascular leakage of albumin. To investigate this hypothesis, urinary albumin excretion and clearance and systemic transvascular albumin leakage (TERalb) were measured in 23 patients with severe clinical atherosclerosis and 25 healthy controls. In addition, renal clearances of three other endogenous plasma proteins (IgG, IgG4, and beta 2-microglobulin) and of creatinine were measured. Measurements of urine and serum proteins were done by enzyme-linked immunosorbent assays. TERalb was measured by the fractional disappearance rate of 125I-albumin from the total intravascular compartment in 1 hour after intravenous injection. Glomerular filtration rate was estimated as creatinine clearance. Urinary albumin excretion (geometric means [95% confidence intervals], 10.5 [6.1 to 18.3] versus 5.7 [4.7 to 6.9] micrograms/min; P < .05), fractional urinary albumin clearance (2.8 [1.6 to 4.8] x 10(-6) versus 1.3 [1.0 to 1.6] x 10(-6); P < .05), and TERalb (6.0 [5.5 to 6.5] versus 5.1 [4.5 to 5.8] %/h; P < .05) were higher in patients than in control subjects. Glomerular charge selectivity (ratio of IgG clearance to IgG4 clearance) was lower in patients than in control subjects (1.5 [1.1 to 2.0] versus 2.3 [2.0 to 2.6]; P < .05). These alterations were independent of blood pressure, glomerular filtration rate, tubular function, and smoking status. It is concluded that atherosclerotic vascular disease is associated with renal and systemic transvascular leakiness for albumin. Theoretically, such leakiness may in addition allow for an increased lipid insudation into the large vessel wall, thereby linking microalbuminuria to atherogenesis.(ABSTRACT TRUNCATED AT 250 WORDS)

Albuminuria↗
PubMed1994

Effects of polymerization heat and monomers from acrylic cement on canine bone.

We investigated the effects of polymerization heat and toxicity of polymethylmetacrylate bone cement in the canine tibial diaphysis. Heat was studied by filling the tibias with either bone cement or bone wax contained in a monomer tight membrane pouch. Toxicity was studied by filling both tibias with cement, with the control side contained in the membrane pouch. Bone blood perfusion was measured by microsphere technic, and bone remodeling by 99mTc-methylene diphosphonate uptake and by histologic technique. In bone exposed to the combination of polymerization heat and monomer, both perfusion and remodeling were impaired. We did not find any effects of polymerization heat alone. We conclude that hot toxic chemicals from bone cement during polymerization may inhibit bone blood perfusion and remodeling, whereas heat alone seems to be of minor importance for the regenerative processes in cemented diaphyseal bone.

Animals↗
PubMed1994

Intracellular location of Mycoplasma genitalium in cultured Vero cells as demonstrated by electron microscopy.

The original two strains of Mycoplasma genitalium were isolated from the human urogenital tract. No other strains have been isolated from this site since then. We have recently succeeded in propagating a third strain from a urogenital specimen from a patient with urethritis in Vero cell cultures. By electron microscopy mycoplasmas were demonstrated intracellularly in about 10% of the examined Vero cells. Various stages of penetration into the cells could be observed. The flask-shaped organisms seemed to penetrate into the cells by the tip-end which included a rodlike structure. The intracellular location of normal mycoplasmas were in membrane-bound vacuoles very close to the nucleus, occasionally together with a few disintegrated organisms. In a few cells additional material was entangling the mycoplasmas in the cytoplasmic vacuoles. The potential for intracellular survival of M. genitalium may help the organism to evade the defence mechanisms of the human body. This trait may be considered a pathogenic property which supports the presumption that M. genitalium has clinical importance.

Animals↗
PubMed1993

[Microalbuminuria--a valuable diagnostic parameter].

The concept of microalbuminuria is reviewed. Measuring the urinary albumin excretion rate and testing for microalbuminuria is well established in the control and treatment of patients with insulin-dependent diabetes mellitus. Microalbuminuria predicts nephropathy and early cardiovascular death. In the presence of microalbuminuria, frequent examinations are warranted for early detection of retinopathy, hypertension and for optimizing the glycaemic control. In patients with non-insulin dependent diabetes, the independent value of microalbuminuria as a cardiovascular risk factor is not yet clarified. The urinary albumin excretion rate should be measured at diagnosis, because the indications are that presence of microalbuminuria reinforces the urge to intervene against other well-documented cardiovascular risk-factors (hypertension, dyslipidemia, tobacco and obesity). In the non-diabetic population there is accumulating evidence that an elevated urinary albumin excretion rate is associated with early cardiovascular morbidity and mortality. Large scale cross-sectional and prospective studies are needed in order to further clarify the role of microalbuminuria as an independent risk factor in the background population.

Albuminuria↗
PubMed1993

[Screening of microalbuminuria with the Micral-Test. A semi-quantitative urinary dipstick].

Microalbuminuria, defined as a urinary albumin excretion rate of 20-200 micrograms/min, predicts diabetic nephropathy and cardiovascular disease in diabetic patients. An increased urinary albumin excretion rate is probably also associated with cardiovascular disease in non-diabetic subjects. Thus, screening for microalbuminuria is of major importance. A semi-quantitative urinary dipstick method, Micral-Test, has been developed for this purpose. In a urine sample collected overnight from each of 1359 subjects the Micral-Test was evaluated with a quantitative ELISA-method as the standard. Sensitivity, specificity and diagnostic specificity in detecting microalbuminuria was 92, 58 and 12% respectively. The prevalence of microalbuminuria was 5.6%. In conclusion, the Micral-Test is highly sensitive in detecting microalbuminuria, but at the expense of a relatively high number of false positive tests.

Adult↗
PubMed1993

[Unsatisfactory results after repeated revision of hip alloplasties].

Sixty one cemented second revision total hip arthroplasties and 18 cemented third revision total hip arthroplasties were studied with emphasis on cause of failure, complications, risk of further revision, and clinical and radiographic outcome of surviving, not further revised patients. Aseptic loosening was the major reason for both second and third revisions followed by recurrent dislocations. Twenty one second revisions failed again. Postoperative dislocation was the major complication, entered in 10/61 second revisions and in 4/18 third revisions. Ten second revisions were reoperated on without exchange of components, but for reasons related to the implant. Clinical and radiographic outcome was favorable, but must be seen in the light of the high rate of further revisions. In 33/53 second revisions and in 5/13 third revisions left for evaluation, the overall outcome was considered unsatisfactory. Reoperations for failed arthroplasties should be the prerogative of highly experienced centers.

Adult↗
PubMed1993

Improved cortical histology after cementation with a new MMA-DMA-IBMA bone cement: an animal study.

The histological response of bone to inert bone wax, conventional polymethylmethacrylate (PMMA), and a new formulation of bone cement, methylmethacrylate/n-decylmethacrylate/isobornylmethacrylate (MMA/DMA/IBMA) was investigated in canine tibial diaphysis. The new formulation of cement is characterized by a reduced exothermic temperature at curing and reduced leakage of chemicals to the adjacent bone. In comparison with bone wax, the MMA/DMA/IBMA bone cement did not differ significantly with respect to periosteal apposition and bone remodeling, although a tendency to inhibit the biological response was encountered. The MMA/DMA/IBMA was clearly superior to PMMA bone cement in respect to both bone necrosis and repair, as well as bone remodeling.

Animals↗