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Biomedical subjects

A Persson

Publications and source records attributed to A Persson.

At least 37 records · Page 2Linked to original sources
PubMed1998

Thermodynamic analysis of protein interactions with biosensor technology.

A methodology using biosensor technology for combined kinetic and thermodynamic analysis of biomolecular interactions is described. Rate and affinity constants are determined with BIAcore. Thermodynamics parameters, changes in free energy, enthalpy and entropy, are evaluated from equilibrium data and by using rate constants and transition state theory. The methodology using van't Hoff theory gives complementary information to microcalorimetry, since only the direct binding is measured with BIAcore whereas microcalorimetry measures all components, including e.g. hydration effects. Furthermore, BIAcore gives possibilities to gain new information by thermodynamic analysis of the rate constants.

Animals↗
PubMed1998

Follow-up of patients with low back pain during pregnancy.

OBJECTIVE: To identify the long-term risk for low back pain among women with previous severe low back pain during pregnancy. METHODS: In a previous prospective study, 79 pregnant women developed low back pain severe enough to require sick leave. Twelve years later a questionnaire was sent to 62 of these women and 84 controls who did not develop severe low back pain during pregnancy. The questionnaire asked about occupation, low back pain in general and during later pregnancies, and sick leave due to low back pain. There were also questions regarding use of oral contraceptives and its possible relation to low back pain. RESULTS: The response rate was 84% in the back pain group and 80% among controls. The two groups were similar according to the percentage of women having had another pregnancy (33 of 52 [63%] versus 39 of 67 [58%]) but ten (19%) of the women with previous low back pain stated they had refrained from another pregnancy because of their fear of low back pain compared with only one control. Almost all women (31 of 33) with previous severe low back pain experienced the same symptoms in a subsequent pregnancy, compared with 17 of 39 (44%) controls. Even when they were not pregnant, women with previous low back pain suffered more often and used more sick leave due to low back pain (44 of 52 versus 43 of 67, chi2 = 5.68, P < .05). The location (sacroiliac joint or lumbar affection) of the previous low back pain did not affect the long-term prognosis. In a logistic regression model, previous low back pain during pregnancy was the only independent risk factor for low back pain during a subsequent pregnancy, whereas an occupation involving physical demand did not affect the results. However, together with previous low back pain during pregnancy, heavy occupation increased the risk for current nonpregnant low back pain. CONCLUSION: Women with severe low back pain during pregnancy have an extremely high risk for experiencing a new episode of severe low back pain during another pregnancy and when not pregnant.

Adult↗
PubMed1997

BIACORE analysis of histidine-tagged proteins using a chelating NTA sensor chip.

While BIACORE instruments are routinely used for kinetic measurements and for the determination of binding constants, the immobilization of a ligand onto the sensor chip surface has to be individually optimized for every system. We show here that the histidine (His) tag, routinely used in protein purification and in detection is an ideal tag for immobilization, despite the intrinsically low affinity between an immobilized metal ion and the His tag. This is due to strong rebinding effects caused by the high surface density of immobilized Ni2+-nitrilotriacetic acid (NTA) on the chips used here. The immobilization of the ligand can be adjusted to a low level using the same chip, such that mass transport limitation and rebinding of the analyte to the immobilized ligand is minimal. Nine different proteins with different numbers of His tags were tested for stable binding to the Ni2+-NTA surface. Most proteins with one His tag dissociate very rapidly from the Ni2+-NTA surface, and the KD for the interaction between His tag and Ni2+-NTA was estimated to about 10(-6) m at neutral pH. In contrast, two His tags are usually found to be sufficient for stable binding. The kinetics of the chaperonin system of Escherichia coli GroEL and GroES were analyzed as a model using this system and found to be very similar to those obtained with covalently immobilized ligands. The sensor chip can be reused many times, because of the powerful regeneration methods. The ligand can be freshly immobilized after each cycle, thus eliminating potential denaturation upon regeneration as a source of error.

Adenosine Triphosphate↗
PubMed1997

Ovarian vein thrombosis with symptoms prior to term--a case report.

A case with ovarian vein thrombosis before delivery is presented. C-reactive protein exceeded 200 mg/l, and the patient was treated for a suspected infection before the true diagnosis was revealed by CT. After aggressive anti-coagulant therapy, a follow-up CT showed complete remission.

Adult↗
PubMed1997

Genetic mapping using fluorescent quantification of allele frequencies in pooled DNA loaded by solid support.

An efficient and labour-saving method for fragment analysis in linkage studies using biotinylated primers and streptavidin-coated combs is presented. The level of streptavidin attached to the combs was used to control the amount of immobilised material. Thus, the need for titration of PCR products to fit the dynamic range of the sequencer was reduced. The method was used to investigate the possibility of quantitating allele frequencies in pools of DNA from family members with the autosomal dominant eye disorder Best's macular dystrophy. The method allowed the detection of one unique allele in a background of 39 other alleles. Using independent datasets, it was further found that the method was able to detect distorted allele frequencies in affected individuals of one family as compared to reference individuals, for markers located more than 30 cM from the disease locus. It was found that this procedure is a powerful alternative to conventional linkage analysis and the method may prove useful in a genome scan for genes involved in complex disorders.

Alleles↗
PubMed1997

Clinical assessment of udder health status of sows at time of weaning with special reference to bacteriology and cytology in milk.

The main objective of this study was to obtain data about the frequencies of teat injuries, udder skin lesions and abnormal palpatory findings of the mammary glands at the day of weaning and 7 days after weaning. Milk samples were collected from mammary glands and teats without clinical changes and from glands and teats showing abnormal clinical appearance. Bacteriological examination was performed and evaluated. The total cell content (TCC) and the polymorphonuclear leucocytes (PMNLs) were counted and used as indicators of inflammatory response. Sixty per cent of the lactations showed teat injuries and (or) udder skin lesions irrespective of lactation number. The prevalence of palpable changes increased gradually from the first to the second and subsequent lactations (15%, 30% and 60%), the increase from the first to the second and from the first to the third and subsequent lactations being significant or highly significant (P < 0.05 and P < 0.001). The average number of teats injured per 'lactation with teat injuries' showed a numerical but not significant decrease (3.0, 3.2 and 2.4, respectively). The average number of palpable changes per 'lactation with palpable changes' varied from 1.7 to 2.5. The teat injuries were numerically more frequent within the two thoracic and first three abdominal teat pairs, varying from 11% to 16%. The clinical appearance of the teat injuries and palpatory changes subsided rapidly, 76% and 49% being scored as clinically normal when the re-examination was performed 7 days after weaning. Irrespective of clinical group, the milk collected at the day of weaning yielded non- as well as alpha- and beta-haemolytic streptococci. The beta-haemolytic streptococci turned out to be more frequently isolated from milk collected from clinically abnormal glands and teats. The limited number of secretion samples obtained and cultured 7 days after weaning yielded staphylococci and Actinomyces pyogenes, which indicated a bacterial flora known to cause infectious mastitis. A cytological comparison between milk from clinically normal and abnormal mammary glands and teats revealed almost significantly or significantly increased levels of TCC and PMNLs (12.17 vs. 17.76 x 10(6) cells/ml and 1.40 vs. 2.77 x 10(6) cells/ml). A comparison between levels of TCC and PMNLs in milk collected from the two clinical groups of sows, but where the bacteriological growth turned out to be negative, also revealed significant increases in the levels of the two cell parameters emanating from clinically abnormal glands and teats. The individual sow, but not herd or lactation, showed a significant influence on the variation of TCC.

Animals↗
PubMed1997

A comparison between one and three years of treatment in uncomplicated childhood epilepsy: a prospective study. II. The EEG as predictor of outcome after withdrawal of treatment.

PURPOSE: We wished to evaluate the prognostic usefulness of various EEG parameters with respect to remission rates after discontinuation of antiepileptic drug (AED) therapy in children treated for epileptic seizures. METHODS: Two hundred forty-four children with uncomplicated epileptic seizures were randomized to either 1 or 3 years of treatment with AEDs. The treatment was then discontinued in patients who had been seizure-free during the last 6 months of their allotted time of treatment (n = 154). After treatment discontinuation, the children were followed for at least 2 years. EEG recordings were performed before treatment was initiated and at regular intervals during treatment. RESULTS: The overall relapse rate was 37%. In many children, the amount of epileptiform activity varied considerably between subsequent recordings made during the treatment. The remission rate was slightly higher for children whose last recordings before AED discontinuation were free of epileptiform activity as compared with children in whom such activity was present. However, children who had irregular generalized spike-wave (SW) activity in the recordings made before discontinuation of treatment had a clearly higher relapse rate (67%) both as compared with children without epileptiform activity (33%) and as compared with children with other types of epileptiform activity (33%) in their last EEG recordings before discontinuation. All children treated for only 1 year whose final EEGs displayed generalized irregular SW activity relapsed. CONCLUSIONS: We conclude that the presence of epileptiform activity does not in itself necessarily influence prognosis after discontinuation of treatment but that certain types of such activity signal a high risk of relapse.

Anticonvulsants↗
PubMed1997

Nerve conduction and autonomic nerve function in diabetic children. A 10-year follow-up study.

In order to study the long-term development of diabetic neuropathy in children with newly diagnosed diabetes mellitus, 144 children were entered in a prospective study of nerve conduction and autonomic nervous function. Neurophysiological recordings of nerve conduction and parasympathetic function (R-R variations) were made at onset of diabetes and after 2, 5 and 10 years. Low sensory nerve conduction and autonomic dysfunction were found in approximately 25% of the children at onset of diabetes when the patients were not yet in complete remission. During years 0-2, an initial improvement of sensory conduction velocities was found. After 2 years, deteriorations in sensory and motor nerve conduction and autonomic nerve function were common and further deterioration was seen over time. A correlation was found between nerve conduction and glycaemic control.

Adolescent↗
PubMed1997

The importance of the Doppler angle.

We examined 118 infrainguinal grafts (103 patients) to determine the effect changes in the angle of theta or Doppler angle had on the accuracy of velocity measurements made with a duplex scanner. Four separate measurements of peak velocity were made on each graft. Three measurements were made with the flow toward the probe at 60 degrees, 50 degrees, 120 degrees (60 degrees the other way). The probe was then turned 180 degrees so the flow was away from the probe and measurements were made at 60 degrees. When the primary cursor was aligned with the vessel wall (Technologist A), the mean velocity at 60 degrees was 69.4 cm/sec and 57.3 cm/sec at 50 degrees, a difference of 12 cm/sec. The same measurements done by Technologist B (primary cursor non aligned with the wall), showed a 10 cm/sec difference (60.7 and 50.5). We saw a consistent difference with even this small difference in the angle of theta throughout the study. The mean velocity obtained by Technologist A when the flow was toward the probe was 61.7. When the probe was turned 180 degrees (flow away from the probe), the mean velocity was 60.5. The same measurements by Technologist B were 51.8 and 50.5. This indicates that the direction of the flow of blood towards or away from the probe does not effect the velocity measurements. Using the vessel wall to line up the primary cursor provides a consistent and easily reproducible reference point to compare measurements made on different days but is less important for single measurements.

Arterial Occlusive Diseases↗
PubMed1996

Comparison between one and three years of treatment in uncomplicated childhood epilepsy: a prospective study. I. Outcome in different seizure types.

PURPOSE: The main purpose of this prospective study was to analyze whether 1 year of treatment was as effective as 3 years with respect to remission rate in children with idiopathic epilepsy. METHODS: Treatment for epileptic seizures was started in 207 children aged 2-16 years. They were randomized to treatment for 1 or 3 years. At the end of the predetermined treatment period, 161 children had been seizure-free for 6 months and the treatment could be gradually withdrawn. RESULTS: The overall remission rate in our group of patients was significantly higher (71%) in the group treated for 3 years than in the group treated for 1 year (53%). However, comparison of remission rates between patients with different seizure types showed statistically significant differences in outcome depending on duration of treatment only in children with complex partial seizures (CPS). CONCLUSIONS: Our results show that 1 year of treatment can be recommended in children with benign partial epilepsy with rolandic spikes (BECT) and in children with simple partial seizures (SPS) but is clearly insufficient in children with CPS. A proper seizure classification is one important tool, although not sufficient, in offering recommendations concerning the duration of treatment in children with idiopathic epilepsy.

Adolescent↗
PubMed1996

Can a physician recognize an older driver with increased crash risk potential?

OBJECTIVE: To identify factors in a medical examination that distinguish convicted older drivers with traffic violations from other drivers. DESIGN: Matched case-control study. SETTING: Two countries in Sweden. SUBJECTS: Thirty-seven drivers older than age 65, whose driving licenses have been temporarily suspended, each matched to one control subject based on age, sex, type of driving license, year of first license, living area, educational level, and annual distance driven. MEASUREMENTS: Case and control subjects were compared with respect to medical history, medication use, blood tests, drawing and memory tests, Mini-Mental State Examination, medical status findings, visual acuity, and brain imaging procedures. MAIN RESULTS: The group of drivers with suspended driving licenses did not differ from matched controls with respect to visual acuity or presence of cardiovascular diseases. However, persons with suspended driving licenses were more likely than control subjects to have suspected or mild dementia (P < .010) and to perform less well on two easily administrated screening tests: copying a cube (P < .010) and 5-item recall (P < .010). Case subjects with crashes had significantly more cardiovascular diseases than case subjects with other moving violations (P < .050). These case subjects with crashes also had significantly more cognitive impairments than control subjects without crashes as shown by a higher clinical dementia rating score (CDR) (P < .001), lower score on the Mini-Mental State Examination (MMSE) (P < .050), and lower level of performance in the copying task (cube) (P < .050) and 5-item recall test (P < .010). They also had evidence of greater cognitive impairment than those case subjects with other moving violations. CONCLUSIONS: Visual acuity and common medical examination did not distinguish convicted older drivers with crashes or other moving violations from controls. There was evidence that even mild cognitive impairment contributed to the risk of losing a driving license because of crashes.

Accidents, Traffic↗
PubMed1996

Characterization of the human surfactant protein D promoter: transcriptional regulation of SP-D gene expression by glucocorticoids.

We have previously described the characterization of genomic clones encoding the entire translated sequence of human pulmonary surfactant protein D (SP-D). We now describe the characterization of a genomic fragment (H5E7) that encodes the entirety of the first translated exon (Exon 2), Intron 1, a short transcribed untranslated sequence (Exon 1; 39 bp), and approximately 4 kb of sequence upstream from the transcription initiation site. The start site was identified by 5'-RACE-PCR cloning and primer extension. A putative TATA box (CATAAATA) was identified approximately 30 bp upstream of the start site. Complete sequencing of a HindIII/SacI fragment (HS-1674) encoding approximately 1.7 kb of sequence 5' to the TATA demonstrated multiple potential cis-regulatory elements including half-site glucocorticoid response elements (GRE), a canonical AP-1 consensus, several AP-1 like sequences, E-box sequences, NF-IL-6 and PEA3 motifs, and putative interferon response elements. H441 lung adenocarcinoma cells, which express low levels of SP-D mRNA, and liver HepG2 cells, were transiently co-transfected with chloramphenicol acetyl transferase (CAT) reporter constructs containing up to 3,000 base pairs of upstream sequence, and with constructs encoding beta-gal. H441 cells transfected with constructs containing at least 161 bp of upstream sequence gave normalized levels of CAT activity greater than or equal to that obtained for parallel positive control transfections using pTK-CAT. Treatment of the cells for 48 h with 50 nM dexamethasone (Dex) gave a 2- to 5-fold increase in CAT activity. Interestingly, a 5'-deletion construct containing 161 bp of upstream sequence (pFS161-CAT) conferred both cell type-restricted and dexamethasone-responsive expression. These studies emphasize the potential complexity of SP-D gene regulation, and further support the hypothesis that the effects of glucocorticoids on SP-D production in vivo are regulated at the level of transcription.

Base Sequence↗
PubMed1996

A long-term study on the health status and performance of sows on different feed allowances during late pregnancy. II. The total cell content and its percentage of polymorphonuclear leucocytes in pathogen-free colostrum and milk collected from clinically healthy sows.

The main objective of this study was to determine the total cell content, TCC, and the percentage of polymorphonuclear leucocytes, PMNLs, in colostrum and milk collected from sows during the first 22 days of lactation. The pH-values during the same sampling period were also determined. It should be emphasized that all the values obtained emanate from bacteriologically negative colostrum and milk. The potential influence of different levels of late gestation feeding regimes was also evaluated. The TCC-values obtained from milk samples during the first 3 weeks of lactation and exceeding the designated threshold of 10 x 10(6) cells/ml varied between 4% and 21%. Within the TCC-limitation of 10-19.99 x 10(6) cells/ml neither the preceding nor the succeeding cell counts exceeded the threshold in 26.8%. TCC-values above 19.99 x 10(6) cells/ml were preceded and succeeded by cell counts below the threshold in 58.8% and 58.8%, respectively. The TCC-levels below the threshold of 10 x 10(6) cells/ml, expressed as geometric least square means, increased significantly from day 1 to day 3 (1.23 x 10(6) cells/ml versus 1.86 x 10(6) cells/ml) and decreased thereafter gradually to day 22 (1.38 x 10(6) cells/ml). When all values were included, the TCC-values increased in a similar pattern from day 1 to day 3 (1.38 x 10(6) cells/ml versus 3.18 x 10(6) cells/ml). The value on day 22 of lactation was still on a significantly elevated level compared with that of day 1 (2.10 x 10(6) cells/ml versus 1.38 x 10(6) cells/ml). The 2 different feeding regimes were not found to influence the TCC-values during the first 22 days of lactation. In the whole material the PMNL-values, expressed as percentages of the TCC, declined from approximately 60% on day 1 of lactation to between 40% and 50% for the remaining sampling period. This decline was comparable with the one seen in the cell class below the threshold of 10 x 10(6) cells/ml. In the 2 cell classes above 9.99 x 10(6) cells/ml, 78.0% and 88.8% of PMNLs on day 1 declined to about 40% on day 22. This might indicate an inflammatory response on day 1 but without any detectable bacteriological growth. The increase in lactation number, if lactation 1 was compared with the following lactations, revealed a significant rise (p < 0.05) in TCC-level and percentage level of PMNLs. A stepwise and significant increase in pH-level occurred between days 1, 3 and 8 (6.18, 6.56, 7.03) followed by a significant decrease to day 22 (6.91) when pH-values from milk of all cell classes were included.

Animal Feed↗
PubMed1996

A long-term study on the health status and performance of sows on different feed allowances during late pregnancy. III. Escherichia coli and other bacteria, total cell content, polymorphonuclear leucocytes and pH in colostrum and milk during the first 3 weeks of lactation.

The objectives of this study were to (1) estimate the clinical status of the mammary glands and (2) compare it with the bacteriological findings, the total cell content (TCC) and its percentage of polymorphonuclear leucocytes (PMNLs) and pH in colostrum and milk secretion of sows on 2 different feeding regimes, high versus low, during late pregnancy. The milk samples were collected from both agalactia post partum (APP) sows and clinically healthy sows. Sows with a rectal temperature exceeding 39.5 degrees C within 48 h after parturition were considered to be diseased in APP and treated medically. The sows were sampled on days 1, 3, 8 and 22 of lactation during 6 consecutive lactations. Irrespective of feeding regimes, 49 out of 77 lactations among the APP sows and 15 out of 96 lactations among the clinically healthy sows revealed E. coli in pure cultures with a concomitant TCC exceeding 10 x 10(6) cell/ml already on the first day of lactation. The healthy sows with E. coli infection were denominated as being subclinically infected sows. The intensity in growth of E. coli successively declined, and the bacteria were finally eliminated between days 3 and 8 of lactation. The TCC were 82 x 10(6) cells/ml and 157 x 10(6) cells/ml in the clinically and subclinically E. coli infected glands, respectively, on the first day of sampling. The TCC declined gradually in both groups of sows, but was still higher than in bacteriologically negative milk on day 22 of lactation. The percentages of PMNLs were 66% and 79% in clinically and subclinically infected glands, respectively, on day 1 of lactation, thereafter decreasing to approximately 50% on day 22 of lactation in both groups of sows. In APP sows, swelling, reddening and/or soreness were registered in 38 out of 87 mammary glands with E. coli mastitis on the first sampling occasion. The TCC in bacteriologically negative colostrum and milk collected from APP sows on day 1 of lactation was significantly higher, 2.27 x 10(6) cells/ml, when compared with the TCC in bacteriologically negative milk secretion from the clinically healthy or subclinically infected sows, 1.38 x 10(6) cells/ml versus 1.51 x 10(6) cells/ml, respectively. The PMNLs were higher on day 1 in clinically healthy sows, 59.6%, than in subclinically infected and APP sows (43.5% and 48.3% respectively). The pH in secretion from clinically or subclinically E. coli infected glands (6.57 versus 6.46) were higher than in bacteriologically negative colostrum samples (6.29) from clinically diseased sows on the first day of sampling. On day 22 of lactation, pH-values had stabilized on a level of approximately 7.00 in all milk samples from earlier bacteriologically positive or negative mammary glands. The 2 feeding regimes, low versus high, were not found to influence TCC, PMNLs or pH except for TCC in bacteriologically negative samples of APP sows (2.69 versus 3.62). The lactation number influenced the PMNLs in both groups of sows with E. coli infected mammary glands, and both the TCC and PMNLs in bacteriologically negative colostrum and milk.

Animal Feed↗