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Biomedical subjects

A Lundin

Publications and source records attributed to A Lundin.

At least 73 records · Page 4Linked to original sources
PubMed1990

Accuracy of digital radiography using stimulable phosphor for diagnosis of pneumothorax.

To evaluate the efficacy of digitized radiography in diagnosing pneumothorax 78 patients were examined with both the conventional film-screen technique and digital radiography. Of these 78 examinations 40 were normal and in 38 a pneumothorax was found. Four observers with different experience reviewed the films. In an ROC analysis no significant differences were found between the two systems. Between the observers, however, there were slight differences, one of them showing significantly lower specificity.

Humans↗
PubMed1990

Increased rate of left predominance associated with adult valvular aortic stenosis.

The anatomy of the coronary arteries was outlined angiographically in 2,190 adult patients in order to determine the proportion of left predominance. Of 253 patients with valvular aortic stenosis 14.3 per cent were found to have left predominance, while the frequency of left predominance in the rest of the patients (1937) was 8.5 per cent. Furthermore, this rate increases with the severity (gradient greater than 50 mmHg) of the aortic stenosis in the absence of aortic valve incompetence. These findings support the current concept of a relationship between adult aortic stenosis and congenital valvular malformation.

Angiography↗
PubMed1989

A new linear plot for standard curves in kinetic substrate assays extended above the Michaelis-Menten constant: application to a luminometric assay of glycerol.

In conventional kinetic substrate assays the standard curve is plotted as observed reaction rate, upsilon obs, versus added substrate concentration, Sadd, and has a linearity limited to Sadd much less than Km. From this plot the blank reaction rate, upsilon bl, is easily estimated but not the contaminating substrate concentration, Scon, present in reagents (unless it is the only blank source). Thus the actual substrate concentration, S = Scon + Sadd, cannot be estimated as required for the various linear plots based on the Michaelis-Menten equation. We have derived an expression, (upsilon obs - upsilon bl)/Vapp = Sadd/(Kmapp + Sadd), containing only those parameters measured for a conventional standard curve (Vapp and Kmapp are obtained from a plot of (upsilon obs - upsilon bl) versus (upsilon obs - upsilon bl)/Sadd). A plot of (upsilon obs - upsilon bl)/Vapp versus Sadd/(Kmapp + Sadd) can be used as a standard curve with the following advantages over the conventional standard curve: (a) For all kinetic substrate assays it is identical and connects the points (0, 0) and (1, 1). Thus deviations from true Michaelis-Menten kinetics or erroneous kinetic constants are easily detected. (b) Since it is linear even above Km, the analytically useful range is considerably extended. (c) For assays with a wide dynamic range it can be used in lin-lin or log-log form. The procedure is illustrated for a kinetic assay of glycerol (Kmapp = 40 mumol/liter). The plot was found to be entirely linear in the range 0.07-100 mumol/liter (glycerol concentration in cuvette).

Adenosine Triphosphate↗
PubMed1989

Automatic luminometric kinetic assay of glycerol for lipolysis studies.

A kinetic assay for glycerol based on the glycerokinase and firefly luciferin-luciferase reactions was developed for the purpose of allowing automatic analysis of large series of incubates from human fat cells. The method includes simplified sampled pretreatment and fully automated analysis, recording, and calculation of data. The upper limit of the dynamic range of the assay was extended from a glycerol concentration in cuvette of 2 up to 100 microM. This is due to a principally new method to linearize the nonlinear part of the standard curve. Recovery experiments reveal 100% glycerol recovery. Within-run and between-run precisions are high with coefficients of variation of between 1.2 and 3.7%. Samples are stable for up to 6 months in an ordinary freezer. The detection limit expressed as 2 SD of the blank result is 0.07 microM glycerol in cuvette, which is slightly lower when compared to the previous luminometric methods. The apparent blank, which is typically 0.4-1.0 microM glycerol in cuvette, has shown significant contributions only from bovine serum albumin, 0.03 microM, and glycerokinase, 0.01 microM. The analytical performance and degree of automation of the glycerol method described in this paper makes it well suited for serial studies of lipolysis in human fat cells in the presence of lipolytic or antilipolytic agents.

Adenosine Triphosphate↗
PubMed1989

Bacteriuria testing by the ATP method as an integral part in the diagnosis and therapy of urinary tract infection (UTI).

Rapid tests for bacteriuria have the highest value, if the test result is available while the patient is with the doctor. At the bacteriological laboratory rapid testing of samples obtained by mail may be cost-effective but is of little clinical value. In a previous study performed at a health care centre using conventional urine culture as a reference the ATP test came out as the most reliable one among several rapid bacteriuria tests. The present study was performed to see how the ATP test could be fitted into the routine of the health care centre. Female patients with UTI symptoms were asked to deliver a urine sample to the health care centre laboratory and to wait for the result before seeing the doctor. After having the symptoms confirmed the doctor based the diagnosis on the ATP value. A low ATP value ruled out UTI and a high ATP value confirmed UTI. In patients with an intermediary ATP value (10-50 nmol/l) a positive nitrite test was used to confirm UTI. Only those patients with intermediary ATP values and negative nitrite test had to wait for conventional urine culture. Thus in most patients the decision on antibiotic therapy or not was based on clinical symptoms and ATP results only. Antibiotics (trimethoprim) were given as single dose or as a conventional 7-day regime in a double-blind comparison. The correlation between the ATP method and conventional culture was good.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Triphosphate↗
PubMed1989

Evaluation of a bioluminescence assay for the detection of bacteriuria.

Bacteriuria defined with urine culture as the reference method was compared with bacterial adenosine triphosphate (ATP) measurements of cystoscopical urine samples from 216 men. Discrepant samples were studied by reculturing and microscopy of the sediment. Results show a good correlation (sensitivity 1.0 and specificity 0.95) between bacteriuria greater than or equal to 10(4) cfu/ml and bacterial ATP greater than 10 nmol/l measured by bioluminescence. Samples with macroscopic hematuria may influence the ATP value and give false positive results.

Adenosine Triphosphate↗
PubMed1988

Microdialysis of adipose tissue and blood for in vivo lipolysis studies.

Glycerol levels (lipolysis index) were continuously monitored in intact rats using simultaneous microdialysis of venous blood and subcutaneous adipose tissue. Dialysis probes (0.5 X 4 mm) were implanted and perfused using a microinjection pump. The basal glycerol levels in perfusates of blood and adipose tissue were stable. Intravenous isoproterenol (isoprenaline) increased the glycerol levels in a similar fashion in blood perfusate as compared with plasma and the dialysate of two different adipose tissue probes implanted in the same animal. Isoproterenol included in the adipose tissue dialysis solvent increased the glycerol level in adipose tissue perfusate but not in the blood perfusate; this indicates a local lipolytic effect of catecholamines. Increases in intravenous doses of isoproterenol caused a transient and marked dose-dependent elevation of glycerol in the adipose tissue perfusate and a gradual but less marked rise of glycerol in blood perfusate. This indicates that glycerol kinetics in blood and adipose tissue differ after catecholamine stimulation. In conclusion, microdialysis of blood and subcutaneous adipose tissue offers new and unique possibilities for in vivo lipolysis studies in intact animals.

Adipose Tissue↗
PubMed1987

Neutrophil locomotion and serum chemotactic and chemokinetic activities in pustulosis palmoplantaris compared with psoriasis.

Twenty patients with palmoplantar pustulosis (PPP) and 21 patients with psoriasis were compared with respect to the chemotactic response and random migration of their neutrophils (PMNs) and to the chemotactic and chemokinetic activities of their serum. The Boyden chamber technique was used. Compared with the reference group, the PPP neutrophils showed a significant decrease in random migration (p = 0.036) and chemotactic response to casein (p = 0.031), but not to zymosan-activated serum. The psoriasis PMNs had normal chemotactic response, but decreased random migration (p = 0.001). The chemokinetic effects of serum from PPP and psoriatic patients on normal neutrophils were increased (for PPP, p = 0.019 and for psoriasis p = 0.024). The chemokinetic activity of the heated sera was decreased and inversely correlated to the serum level of IgA in both disorders (PPP, p = 0.021; psoriasis, p = 0.013). The chemotactic activity of serum on normal PMNs was decreased in both conditions (PPP, p = 0.001; psoriasis, p = 0.047); this was due to the presence of chemotactic factor inhibitors in 34% of the sera. It seems likely that the high chemokinetic effect of serum both from the PPP and from the psoriasis patients compensates for the slightly low or normal migratory activity of neutrophils from these patients.

Adolescent↗
PubMed1987

High levels of hyaluronate in suction blister fluid from active psoriatic lesions.

Hyaluronate concentrations were measured in suction blister fluid from blisters raised on the abdominal skin of 12 healthy control subjects, on unaffected skin of 14 patients with psoriasis, and on lesional skin from 12 of these patients. The concentrations of hyaluronate in blister fluid from the controls and from the uninvolved skin of patients with psoriasis were within the same range (2.9-10.5 and 2.4-7.8 mg/l, respectively). Six of the patients had active, widespread, untreated psoriasis and in these cases the hyaluronate concentration in blister fluid from lesional skin was greatly increased (24-30 mg/l). Patients with stable or regressing psoriasis had no significant increase in hyaluronate levels in the blister fluid from lesional skin compared with the controls (range 4.6-12.4 mg/l). Patients with active psoriasis had significantly higher serum hyaluronate concentrations than the controls and those with inactive psoriasis.

Adult↗
PubMed1987

Comparison between a swim-up and a Percoll gradient technique for the separation of human spermatozoa.

Two methods of separating human sperm were compared using twenty-two semen samples. The sperm were separated by a swim-up technique or by self-migration on a Percoll gradient followed by medium change. After separation, the sperm obtained were assessed for progressive motility, ATP content, energy charge index ([ATP + 0.5 ADP]/[ATP + ADP + AMP]) and morphology. In general, and especially for semen samples containing less than 20 X 10(6) sperm/ml, separation by Percoll gradient selected sperm that were superior to those separated by the swim-up technique. The relatively high energy charge index (greater than 0.8) showed that the sperm tolerated the separation conditions well. It is suggested that self-migration on a Percoll gradient should prove useful for obtaining sperm of high quality.

Adenosine Triphosphate↗
PubMed1986

Screening for Duchenne muscular dystrophy: an improved screening test for creatine kinase and its application in an infant screening program.

A kinetic bioluminescence assay with optimized reagent conditions has been developed for application as a screening test for increased creatine kinase (CK) activities in dried blood spots. This test is used for the early detection of Duchenne muscular dystrophy (DMD) in a voluntary CK screening program in West Germany. Of the 176,600 boys tested up to December 31, 1984, 48 who were less than 6 months old had certain or probable DMD (frequency 1: 3679). In 1983 and 1984, the rate of false positive results was 0.016% for a cut-off activity 300 U/liter and 0.061% for a cut-off activity 180 U/liter. Long-term counseling is offered to families of newly detected DMD patients in order to facilitate the aims of the screening program, namely, avoidance of secondary cases in affected families, early professional care for the sick child, and the early opportunity to make the appropriate decisions for a life with an handicapped child. Two types of a benign hereditary blood anomaly were also detected by CK screening (CK-BB inside erythrocytes or thrombocytes).

Age Factors↗
PubMed1986

Isolation and characterization of human factor VIII: molecular forms in commercial factor VIII concentrate, cryoprecipitate, and plasma.

Human factor VIII has been isolated from a high purity factor VIII concentrate by immunoaffinity chromatography and HPLC on Mono Q gel. Two fractions of factor VIII were obtained with a specific activity of approximately equal to 7000 units/mg. The major fraction contained eight peptide chains of 200, 180, 160, 150, 135, 130, 115, and 105 kDa plus one doublet chain of 80 kDa. The minor fraction contained one peptide chain of 90 kDa plus the chain of 80 kDa. Both fractions were activated by thrombin to the same extent. Amino-terminal amino acid sequence analysis was performed on the 180-kDa, 130-kDa, and 90-kDa chains and showed an identical amino-terminal sequence in these chains. Each chain from 200 kDa to 90 kDa was linked to one 80-kDa chain by a metal-ion bridge(s). Studies on factor VIII in plasma and cryoprecipitate, prepared and gel filtered in the presence of protease inhibitors, showed that one 200-kDa plus one 80-kDa chain were the only or dominating chains in the materials and may represent native factor VIII. The results indicated that all chains from 180 kDa to 90 kDa are fragments of the 200-kDa chain. All of these more or less fragmented chains form active factor VIII complexes with the 80-kDa chain.

Amino Acid Sequence↗
PubMed1986

On the use of adenosine triphosphate for estimation of motility and energy status in human spermatozoa.

Following the development of a reliable technique for analysis of total ATP in semen, the ATP concentration of untreated human ejaculates was compared with progressive sperm motility during 3 continuous days following ejaculation. As correlation was poor between these variables, spermatozoa were separated by self-migration on Percoll gradients and washed free of Percoll solution. ATP concentration and sperm motility was then assessed. Aliquots of separated sperms were transferred to separate tubes, and increasing concentrations of sera were added prior to incubation at 37 degrees C for 4 days. Under these conditions a good correlation between specific progressive motility and specific ATP content was found (r = 0.88). A high concentration of human blood serum (10% v/v) was found to be necessary for maintainance of motility, but neither the addition of bovine serum albumin nor an increase in the glucose concentration had any effect on sperm motility or on the ATP concentration. Addition of different fractions of human blood serum indicated that the components mainly responsible for maintaining sperm motility are greater than 10,000 daltons. Our findings strongly indicate that ATP assessment can be used to estimate the energetic condition of a human sperm population after its separation from seminal plasma. It is suggested that this in vitro system can be used to define optimal conditions for sperm function.

Adenosine Triphosphate↗
PubMed1986

Evaluation of rapid methods for the detection of bacteriuria (screening) in primary health care.

The diagnostic performance of six methods for bacteriuria testing has been studied in 781 urine specimens obtained in primary health care, using conventional culture as reference method. The cut-off limits for classification of test results into positive and negative have been optimized with respect to diagnostic performance in primary health care. With optimized tests the following diagnostic efficiencies were obtained: Bacterial ATP, 0.94; Bacterial count in sediment, 0.93; Nitrite test, 0.92; Dipslide test, 0.92; White cell count in sediment; 0.87; Goffulocyte esterase test; 0.83. The diagnostic performance was also studied for all combinations of two tests. The highest diagnostic efficiency (0.96) was obtained by combining the ATP and dipslide tests. High diagnostic efficiencies can be obtained by a rapid primary test, using other tests for follow-up testing of specimens with intermediate or uninterpretable primary results. The most promising results were obtained by using ATP as the primary test, with follow-up testing of specimens with 3-25 nmol/l of ATP (12 per cent of the specimens). Follow-up testing by conventional culture resulted in overall diagnostic efficiency of 0.98. By performing the nitrite test on specimens with intermediary ATP-results, 81 per cent of the patients with UTI can be classified without culture. Only patients with intermediary ATP and negative nitrite results (10 per cent of the total number) will have to wait for final diagnosis based on conventional culture. Some alternative strategies to combine available methods are discussed in detail. Major advantages of the ATP test are that the test can be performed while the patients are waiting; it provides a numerical and objective result, and, in contrast to culture, it is not influenced by adhesion of bacteria to somatic cells.

Adenosine Triphosphate↗
PubMed1985

Effect of hormones on growth and ATP content of a human prostatic carcinoma cell line, LNCaP-r.

The use of ATP content as a measurement for cell growth was evaluated in the LNCaP prostatic cancer cell line. ATP content was found to correlate well with cell counts and was an easy and reliable method for following the effect of substances on cell growth. During cultivation for 9 days no effect on cell counts or ATP content could be seen when testosterone (10(-10) to 10(-6) M), estradiol-17 beta (10(-10) to 10(-5) M), 5 alpha-DHT (10(-9) to 10(-6) M), prolactin, vitamin A, or antiandrogen was added to the cell medium in different combinations. However, a weak positive effect was seen on the mitotic index when 10 or 100 nM 5 alpha-DHT was added to the cells, whereas 1 microM 5 alpha-DHT inhibited cell growth. Thus despite the fact that this LNCaP line contained 16 fmol androgen receptor/mg protein (Kd 0.6 nM), it is unresponsive to hormones and should be designated LNCaP-r (resistant). Chromosome analysis revealed that a shift in the modal chromosome number had occurred from the original LNCaP line, which could account for the lack of hormonal sensitivity.

Adenosine Triphosphate↗