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Biomedical subjects

T Nilsson

Publications and source records attributed to T Nilsson.

At least 91 records · Page 5Linked to original sources
PubMed1998

[Results after surgery of incisional hernias].

The purpose of this paper is to describe the subjective results after operation for ventral hernia. Patients operated for ventral hernia in the period from January 1, 1988 to December 31, 1992 were sent a questionnaire with a response rate of 87%. Forty-five percent had lasting discomfort, 30% were absent due to illness more than eight weeks after the operation and 22% were not able to go to work. These factors increase with the number of hernia operations. Regardless of the number of operations, about 70% of the patients wanted a new operation should the hernia recur. It is therefore important to give the patient an objective and detailed information to prevent from unrealistic expectations of the results of ventral hernia operation.

Adolescent↗
PubMed1998

Inter-laboratory validation of solid-phase microextraction for the determination of triazine herbicides and their degradation products at ng/l level in water samples.

The accuracy and precision of solid-phase microextraction (SPME) were validated in an inter-laboratory study including ten laboratories for the analysis of triazine herbicides and their metabolites at ng/l level in aqueous samples. The SPME conditions were optimised in order to obtain maximum sensitivity. Especially, salt addition and choice of the SPME fibre coated with Carbowax-divinylbenzene increased the sensitivity. The average detection limits were in the range from 4 to 24 ng/l for the triazine herbicides, and 20 and 40 ng/l for desisopropylatrazine and desethylatrazine, respectively. The average r2 values of the calibration curves were above 0.99 for all of the analytes. The statistical data treatment was performed in accordance with the International Standardisation Organisation (ISO) standard 5725. Relative repeatability standard deviations between 6 and 14% and relative reproducibility standard deviations between 10 and 17% were found. The determined concentrations of the reference sample compared well to the "true" values, thus proving the good accuracy of the method. It is concluded that SPME is a reliable technique for the quantitative analysis of water samples containing triazine herbicides in concentrations around the European limit of 100 ng/l for individual pesticides in drinking water.

Calibration↗
PubMed1998

Overexpression and purification of cytochrome c oxidase from Rhodobacter sphaeroides.

The aa3-type cytochrome c oxidase of Rhodobacter sphaeroides has been overexpressed up to seven fold over that in wild-type strains by engineering a multicopy plasmid with all the required oxidase genes and by establishing optimum growth conditions. The two operons containing the three structural genes and two assembly genes for cytochrome c oxidase were ligated into a pUC19 vector and reintroduced into several oxidase-deleted R. sphaeroides strains. Under conditions of relatively high pH and maximal aeration, high levels of expression were observed. A smaller expression vector, pBBR1MCS, and a fructose promoter (fruP)5 were found not to enhance cytochrome c oxidase expression in R. sphaeroides. An improved cytochrome c oxidase purification protocol is reported, which combines histidine elution from a nickel affinity column and anion-exchange chromatography, and results in a higher yield and purity than previously obtained.

Chromatography, Affinity↗
PubMed1998

D4 dopamine receptor gene exon III polymorphism and obesity risk.

Many genes have been identified that may play a role in increasing individual susceptibility to obesity. Reduced dopamine function appears to play a role in dysfunctional eating patterns and may predispose some individuals to obesity. The long version of the D4 dopamine receptor gene (D4DR) has been shown to alter receptor function and reduce intracellular response to dopamine. It also has been associated with novelty-seeking-related personality traits that are found with greater frequency in obese individuals. We examined the association between the long alleles of the D4DR and obesity in a sample of 115 obese patients participating in a weight management program. No direct relationship was found between the D4DR and body mass or novelty-seeking-related personality traits. We constructed four models of increased obesity risk that included combinations of traditional risk factors (i.e., long-term history of obesity, parental obesity, a body mass index > 40) and elevations on the novelty-seeking-related scales of the Karolinska Scales of Personality. There was a significant increase in the frequency of the D4DR long alleles in individuals defined as high risk using the combination of novelty-seeking-related personality traits, severe obesity (i.e., BMI > 40), and any other traditional risk factor, but not with the traditional risk factors alone. These preliminary data suggest a potential role for the D4DR gene in increasing obesity susceptibility.

Adult↗
PubMed1998

Pulmonary angiography: a safe procedure with modern contrast media and technique.

Pulmonary angiography (PA) for decades has been accepted as the gold standard for the diagnosis of pulmonary embolism (PE). Apprehensions that the procedure is expensive, invasive and thus associated with both fatal and non-fatal complications has more or less limited its use to patients presenting a non-diagnostic lung scan. However, this opinion originates from earlier studies. Increasing clinical demands for faster and safer diagnostics, together with improved techniques and safer contrast media, has led to an increased use of PA. In order to evaluate the complication rate, we retrospectively studied the case records of 707 consecutive patients who had undergone PA. During 1990-1994, 728 patients underwent PA at Danderyd and Huddinge University Hospital. Selective pulmonary angiography (cine or digital subtraction angiography), non-ionic, low-osmolar contrast media and modern pigtail catheters were used. Standard volumes were 40 ml at 2 s for each injection. Pressure measurements were made in 376 patients. A test injection was made in all patients in order to assess the flow rate. Experienced radiologists as well as residents performed the examinations and a total of 707 angiography protocols and clinical records were available for review in search of complications associated with the procedure. No deaths occurred. One major non-fatal complication (bleeding in the groin requiring surgery) was reported in one case. Moderate/minor complications (i. e. transient angina and cardiac failure, minor haematomas, urticaria) occurred in 10 patients (1.4 %). With modern contrast media and technique, pulmonary angiography is a safe procedure.

Adolescent↗
PubMed1998

The relations of microalbuminuria to ambulatory blood pressure and myocardial wall thickness in a population.

OBJECTIVES: To examine the relationship between microalbuminuria (20-200 microg min(-1)) and 24 h ambulatory blood pressure and heart wall thickness, in a representative population sample of men and women aged 56-65 years. DESIGN: Every second individual aged 56-65 years (n=488) in the district, was invited for a health examination, which included determination of urinary albumin and creatinine (overnight sample). The highest and lowest decentile of urinary albumin/creatinine ratio were compared. SETTING: The district of the Primary Health Care and Research Centre of Mölnlycke, Sweden. SUBJECTS: After excluding 2 individuals with a urinary albumin excretion exceeding 200 microg min(-1). 26 subjects (group 1) could be compared with 27 subjects in the lowest decentile (group 2). MAIN OUTCOME MEASURES: Comparison between the determinations of the ambulatory blood pressure and echocardiographic variables in the two groups. RESULTS: Group 1 had significantly higher 24 h ambulatory blood pressure, and heart septum and posterior wall thickness as well as significantly higher fasting blood glucose and serum triglyceride concentrations. The differences in blood pressure (P < 0.05) but not heart wall thickness remained significant (P<0.05) after excluding subjects with hypertension, angina pectoris, treated diabetes mellitus, and/or history of heart or cerebrovascular disease. When excluding individuals with both treated and untreated diabetes mellitus, fasting blood glucose concentration was higher in group 1. The waist-hip ratio, weight and body mass index did not differ between the groups. CONCLUSIONS: The findings indicate that microalbuminuria is related to signs of cardiovascular and metabolic influence and therefore could be a valuable tool for grading the risk of later cardiovascular morbidity.

Aged↗
PubMed1998

Potential of carotid ultrasonography in the diagnosis of coronary artery disease: a comparison with exercise test and variance ECG.

BACKGROUND AND PURPOSE: Carotid artery atherosclerosis has been shown to correlate with coronary artery disease (CAD). This study evaluates the capacity of duplex ultrasonography of the carotid arteries as a tool in the diagnosis of CAD in comparison with exercise stress test and variance ECG. METHODS: Carotid ultrasonography, exercise stress test, and variance ECG were performed in 184 symptomatic patients evaluated with coronary angiography. The diagnostic capacity of the studied noninvasive methods was assessed by use of receiver operating characteristic (ROC) curves constructed by successive consideration of several cut points, such as (1) the presence of unilateral/bilateral plaques and (2) cross-sectional common carotid artery (CCA) intima-media (IM) area from 10 to 30 mm2 for ultrasonography; (1) ST depression > or =0.1 mV and > or =0.2 mV with and (2) without chest pain for exercise test; and electrical variability index from 50 to 100 for variance ECG. RESULTS: Coronary angiography revealed the presence of CAD (> or =50% luminal stenosis in 1 or more major epicardial arteries) in 147 patients (80%). Identification of carotid plaques on one or both sides and calculation of the left-sided (but not right-sided) CCA IM area provided a significant discrimination (P<.001 and P<.01, respectively) of patients with CAD. The discriminating capacity of the ultrasound procedures was equal to that of variance ECG and exercise test with ST depression criterion only but somewhat lower than that of exercise test with the combined chest pain and ST depression criterion (P<.05). However, at the chosen cut points, carotid plaque identification offered higher sensitivity than exercise test with either criterion (P<.01 and P<.001, respectively). CONCLUSIONS: Carotid ultrasonography is a useful diagnostic method that is comparable to exercise test and variance ECG for detection of CAD in a high-prevalence population.

Adult↗
PubMed1998

Tobacco use and exposure to environmental tobacco smoke in relation to certain work characteristics.

This study aims to describe the prevalence of smoking, snuff use, and exposure to environmental tobacco smoke (ETS) in relation to occupation among common female and male workers in Sweden. The associations between shift work, job strain, and tobacco use and exposure to ETS are assessed. The results are based on questionnaire data of 2,584 men and 2,836 women randomly selected from 63 occupations in two counties in Sweden. The prevalence of smoking ranges from 10% (95% CI 4.5-16%, police officers) to 42% (95% CI 29-55%, packing workers) in men, and between 8% (95% CI 2-14%, dentists) and 51% (95% CI 37-65%, packing workers) in women. Snuff use is more common among men (range 11-44% in different occupations) than among women (range 0-7%). The prevalence of exposure to passive smoking in this study ranges from 0.9% to 26% in men and from 0% to 30% in women. Shiftwork is significantly associated with current smoking, and job strain is significantly related to exposure to ETS. Ages between 18 and 29 years experienced an increased risk of exposure to ETS compared to older age groups. In conclusion, this study shows that tobacco use and exposure to ETS is still a major problem in the Swedish workplace.

Adolescent↗
PubMed1998

Localization of three human polypeptide GalNAc-transferases in HeLa cells suggests initiation of O-linked glycosylation throughout the Golgi apparatus.

O-glycosylation of proteins is initiated by a family of UDP-N-acetylgalactosamine:polypeptide N-acetylgalactos-aminyltransferases (GalNAc-T). In this study, we have localized endogenous and epitope-tagged human GalNAc-T1, -T2 and -T3 to the Golgi apparatus in HeLa cells by subcellular fractionation, immunofluorescence and immunoelectron microscopy. We show that all three GalNAc-transferases are concentrated about tenfold in Golgi stacks over Golgi associated tubular-vesicular membrane structures. Surprisingly, we find that GalNAc-T1, -T2 and -T3 are present throughout the Golgi stack suggesting that initiation of O-glycosylation may not be restricted to the cis Golgi, but occur at multiple sites within the Golgi apparatus. GalNAc-T1 distributes evenly across the Golgi stack whereas GalNAc-T2 and -T3 reside preferentially on the trans side and in the medial part of the Golgi stack, respectively. Moreover, we have investigated the possibility of O-glycan initiation in pre-Golgi compartments such as the ER. We could not detect endogenous polypeptide GalNAc-transferase activity in the ER of HeLa cells, neither by subcellular fractionation nor by situ glycosylation of an ER-retained form of CD8 (CD8/E19). However, upon relocation of chimeric GalNAc-T1 or -T2 to the ER, CD8/E19 is glycosylated with different efficiencies indicating that all components required for initiation of O-glycosylation are present in the ER except for polypeptide GalNAc-transferases.

Base Sequence↗
PubMed1998

Differences in co-variation of inorganic elements in the bulk and surface of human deciduous enamel: an induction analysis study.

This paper demonstrates a method for determination of co-variation between some inorganic elements in the bulk and surface areas of human tooth enamel. The technique is based on a computerised induction analysis of data obtained by secondary ion mass spectrometry (SIMS). When comparing the present data with an earlier study from our laboratory, it became evident that with only a moderate increase in the amount of data for the induction analysis, the results increased very considerably in reliability and precision. The patterns of co-variation between different elements differed between the bulk- and surface enamel. Only Mg expressed a similar pattern. In the bulk enamel the elements Na and P expressed a high degree of co-variation. Similarly, Mg and C expressed a high degree of co-variation. Mg was an element often found to co-vary with bulk enamel elements. In the enamel surface, F and Cl co-varied. In addition, Cl was an element often found to co-vary with other enamel surface elements.

Carbon↗
PubMed1998

The mechanism of binding of low-molecular-weight active site inhibitors to human alpha-thrombin.

The thrombin inhibitors argatroban, efegatran, NAPAP, CH 1091, CH 248, inogatran and melagatran have been characterised with respect to their mechanism of binding to human alpha-thrombin. Stopped-flow spectrophotometry was used to follow thrombin-catalysed hydrolysis of the chromogenic substrate S-2238 in the presence of inhibitors. The rate of onset or decay of inhibition was evaluated using progress curve analysis. It was possible to obtain apparent association and dissociation rate constants from the dependence of the rates on the inhibitor concentrations. Inhibition constants calculated from the association and dissociation rate constants were in good agreement with those calculated from steady-state rates. The binding of 6 inhibitors was also monitored directly using stopped-flow spectrofluorimetry when two kinetic components were found with all inhibitors. The faster component accounted for the largest part of the change in the intrinsic fluorescence of thrombin induced by inhibitor binding and was dependent on the inhibitor concentration. The slower component was independent of the concentration of the inhibitor. The concentration dependence of the faster component was linear with the compounds argatroban, NAPAP, CH 1091 and melagatran and hyperbolic with the compounds CH 248 and inogatran. The values of the apparent second-order rate constants at pH 7.4 and 37 degrees C range from slow to rapid binding in the interval 16-78 x 10(6) M-1 s-1, which is somewhat higher than 1-34 x 10(6)M-1 s-1 obtained from progress curve analysis of the onset of inhibition. The present results support a mechanism that includes rearrangement of a weak initial thrombin-inhibitor complex towards a tighter complex. Moreover, at least one additional step is required in the mechanism. In this model, the rate-limiting step for the binding of the inhibitor at concentrations in the nanomolar range depends on the primary interaction between the inhibitor and native thrombin.

Antithrombins↗
PubMed1998

Mortality from asthma and cancer among sulfite mill workers.

OBJECTIVES: The aims of the present case-referent study were to investigate whether sulfite workers show increased mortality from asthma, chronic obstructive pulmonary disease or certain malignancies of interest in relation to sulfite mill work. The main exposure from the pulping processes is from sulfur dioxide, wood dust and terpenes. METHODS: The subjects of the study were all the men who died between 1960 and 1989 and who were aged 40 to 75 years at death (N = 780) in the parishes surrounding 3 sulfite mills. The men who died from asthma (N = 13), COPD (N = 20), lung cancer (N = 33), stomach cancer (N = 35), or brain tumor (N = 10) formed the case group. All the subjects, except the cases in question, were used as referents. As a proxy variable of exposure, job titles from the registers of deaths and burials were used, and 24% of the subjects were classified as exposed. RESULTS: There was an increased mortality from asthma [odds ratio(OR) 2.8, 90% confidence interval (90% CI) 1.1-6.8] and brain tumors (OR 3.3, 90% CI 1.2-8.9) among the sulfite workers. The mortality due to lung cancer was not significantly increased (OR 1.4, 90% CI 0.7-2.6), and there was a reduced mortality from stomach cancer (OR 0.4, 90% CI 0.2-0.9). CONCLUSIONS: The increased asthma mortality may be due to accidental exposure to irritating gases, such as sulfur dioxide. The increased risk for brain tumors has no obvious explanation.

Adult↗
PubMed1997

Overexpression of the dynamitin (p50) subunit of the dynactin complex disrupts dynein-dependent maintenance of membrane organelle distribution.

Dynactin is a multisubunit complex that plays an accessory role in cytoplasmic dynein function. Overexpression in mammalian cells of one dynactin subunit, dynamitin, disrupts the complex, resulting in dissociation of cytoplasmic dynein from prometaphase kinetochores, with consequent perturbation of mitosis (Echeverri, C.J., B.M. Paschal, K.T. Vaughan, and R.B. Vallee. 1996. J. Cell Biol. 132:617-634). Based on these results, dynactin was proposed to play a role in linking cytoplasmic dynein to kinetochores and, potentially, to membrane organelles. The current study reports on the dynamitin interphase phenotype. In dynamitin-overexpressing cells, early endosomes (labeled with antitransferrin receptor), as well as late endosomes and lysosomes (labeled with anti-lysosome-associated membrane protein-1 [LAMP-1]), were redistributed to the cell periphery. This redistribution was disrupted by nocodazole, implicating an underlying plus end-directed microtubule motor activity. The Golgi stack, monitored using sialyltransferase, galactosyltransferase, and N-acetylglucosaminyltransferase I, was dramatically disrupted into scattered structures that colocalized with components of the intermediate compartment (ERGIC-53 and ERD-2). The disrupted Golgi elements were revealed by EM to represent short stacks similar to those formed by microtubule-depolymerizing agents. Golgi-to-ER traffic of stack markers induced by brefeldin A was not inhibited by dynamitin overexpression. Time-lapse observations of dynamitin-overexpressing cells recovering from brefeldin A treatment revealed that the scattered Golgi elements do not undergo microtubule-based transport as seen in control cells, but rather, remain stationary at or near their ER exit sites. These results indicate that dynactin is specifically required for ongoing centripetal movement of endocytic organelles and components of the intermediate compartment. Results similar to those of dynamitin overexpression were obtained by microinjection with antidynein intermediate chain antibody, consistent with a role for dynactin in mediating interactions of cytoplasmic dynein with specific membrane organelles. These results suggest that dynamitin plays a pivotal role in regulating organelle movement at the level of motor-cargo binding.

Antigens, CD↗
PubMed1997

Inhibition of phosphatases and increased Ca2+ channel activity by inositol hexakisphosphate.

Inositol hexakisphosphate (InsP6), the dominant inositol phosphate in insulin-secreting pancreatic beta cells, inhibited the serine-threonine protein phosphatases type 1, type 2A, and type 3 in a concentration-dependent manner. The activity of voltage-gated L-type calcium channels is increased in cells treated with inhibitors of serine-threonine protein phosphatases. Thus, the increased calcium channel activity obtained in the presence of InsP6 might result from the inhibition of phosphatase activity. Glucose elicited a transient increase in InsP6 concentration, which indicates that this inositol polyphosphate may modulate calcium influx over the plasma membrane and serve as a signal in the pancreatic beta cell stimulus-secretion coupling.

Animals↗
PubMed1997

Perceived coping capacity: a comparison between obese patients and patients on long-term sick leave.

Overweight is a significant health problem and perceived by many as a disability. While obese persons in the general population are no more likely to suffer from mental disorders, many obese individuals experience significant difficulties coping with their weight and weight-loss failures. The purpose of this study was to investigate the similarities and differences in coping capacity among obese and disabled individuals. We compared a group of obese adults (76 consecutive obese patients, 82% female) with unemployed long-term sick leave disability patients (59 consecutive patients, 46% female) who had an average of 13 +/- 9 months on disability. We used the Perception of Cognitive Structure, Emotion and Control questionnaire (PASEC), which assesses an individual's coping capacity for general problems in life and to specific health problems. Both groups significantly differed from PASEC normative data, suggesting that they had more negative and harmful emotional perceptions of their lives than individuals in the normative sample. Compared to long-term sick leave patients' perceptions of disabilities, obese patients perceived their weight problems with more negative and harmful emotional investment, even after adjustment for gender differences in the groups. This suggests that obese patients may experience substantial difficulties in coping with their weight problems.

Adaptation, Psychological↗
PubMed1997

Development of fatigue symptoms during simulated driving.

Why do people sometimes allow themselves to be overcome by fatigue? Ancient human survival may have depended on ignoring fatigue. Its modern occurrence in the absence of strain may further render us insensitive to its warning value. To test whether deliberate monitoring of certain symptoms may help drivers and other workers realize when they need to rest to avoid hazard, the development of fatigue while driving a simulator was objectively measured in terms of how many persons quit driving as a function of time. Some subjects asked to stop after 90 minutes; others lasted 240 minutes. Grouping data from an adapted Pearson [(1957) Journal of Applied Psychology, 44, 186-191] fatigue checklist revealed a curious phenomenon. No matter how long subjects drove before wanting to quit, they still developed much the same subjective level of fatigue at the end. This suggests that people do not differ greatly in how much fatigue they can tolerate but rather how quickly they reach a certain critical level of fatigue. Averaging fatigue scores backwards from the time subjects quit produced a function similar to the quitting function. Similar treatment of the other data revealed certain clusters of symptoms whose development also paralleled the development of fatigue.

Adolescent↗
PubMed1997

Adding a visual linear scale probability to the PIOPED probability of pulmonary embolism.

PURPOSE: Reporting a lung scintigraphy diagnosis as a PIOPED categorical probability of pulmonary embolism offers the clinician a wide range of interpretation. Therefore the purpose of this study was to analyze the impact on lung scintigraphy reporting of adding a visual linear scale (VLS) probability assessment to the ordinary PIOPED categorical probability. MATERIAL AND METHODS: The study material was a re-evaluation of lung scintigrams from a prospective study of 170 patients. All patients had been examined by lung scintigraphy and pulmonary angiography. The scintigrams were re-evaluated by 3 raters, and the probability of pulmonary embolism was estimated by the PIOPED categorization and by a VLS probability. The test was repeated after 6 months. RESULTS: There was no significant difference (p > 0.05) in the area under the ROC curve between the PIOPED categorization and the VLS for any of the 3 raters. Analysis of agreement among raters and for repeatability demonstrated low agreement in the mid-range of probabilities. CONCLUSION: A VLS probability estimate did not significantly improve the overall accuracy of the diagnosis compared to the categorical PIOPED probability assessment alone. From the data of our present study we cannot recommend the addition of a VLS score to the PIOPED categorization.

Angiography↗