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B Karlsson

Publications and source records attributed to B Karlsson.

At least 19 recordsLinked to original sources

Incidence of asthma among workers exposed to sulphur dioxide and other irritant gases.

The aim of the present study was to investigate whether repeated peak exposure (gassings) to sulphur dioxide (SO2) and other irritant gases increases the risk of new-onset asthma. A questionnaire was sent to 4,112 sulphite workers, of whom 1,919 completed the questionnaire and 396 completed the short-form questionnaire, which was sent out as a last reminder. A sample of 130 nonrespondents completed a telephone interview using the short-form questionnaire. The incidence of adult-onset, physician-diagnosed asthma during employment duration was analysed in relation to exposure to SO2 and gassings giving rise to respiratory symptoms. Incidence rates, as well as incidence rate ratios with 95% confidence interval (CI), were calculated. Further Cox regression models were used allowing assessment of hazard ratios (HR) stratified for sex and adjusted for atopy, smoking habits and age. The incidence rate for asthma among sulphite mill workers reporting gassings of SO2 was 6.2 out of 1,000 person-yrs, compared with 1.9 out of 1,000 person-yrs among subjects unexposed to SO2 and any gassings (HR (95% CI) 4.0 (2.1-7.7)). Among males reporting gassings to SO2, the HR (95% CI) for asthma was 5.8 (2.6-13) compared with unexposed males. In conclusion, repeated peak exposure to sulphur dioxide increased the incidence of asthma during work in sulphite pulp mills, which supports the hypothesis of irritant-induced asthma.

Adolescent↗

Paternal investment directly affects female reproductive effort in an insect.

Female reproductive effort can be influenced by the quality of her mate. In some species, females increase their reproductive effort by differentially allocating resources after mating with high-quality males. Examination of female reproductive effort in relation to male quality has implications for estimating the evolvability of traits and for sexual-selection models. Accurate quantification of reproductive investment is not possible in many species. Butterflies are an exception, as most nectar-feeding species emerge with almost intact reproductive resources, and in some species males provide nutrients at mating that enhance female fecundity. By manipulating male donations and using radioactive isotopes, we quantified the effect of variation in nutrient provisioning on female reproductive effort in two butterfly species. In the greenveined white butterfly, Pieris napi, females increased their reproductive effort after receiving large male donations. By contrast, in the speckled wood, Pararge aegeria, where males do not provide nutrients, female reproductive effort was independent of male ejaculate. Increased reproductive effort in Pieris napi resulted from the production of more eggs, rather than from investing more resources per egg. In this species donating ability is heritable; hence females laying more eggs after mating with high-donating males benefit both through higher fecundity and through the production of high-donating sons.

Animals↗

Pertreatment radiation induced oedema causing acute hydrocephalus after radiosurgery for multiple cerebellar metastases.

BACKGROUND: Most complications of radiosurgery occur after 6-12 months and some long term complications up to after 5-10 years. Although severe, immediate side effects are rare, we report a patient who shows that this possibility should be taken into account when large volumes are treated especially in the posterior fossa. CASE REPORT: A patient was treated with radiosurgery for multiple brain metastases, of which 5 were located in the posterior fossa. Deterioration occurred, radiosurgery was halted abortion and CT showed acute hydrocephalus caused by a significant edema in the posterior fossa, not present in an MR examination performed some 6 hours earlier. After intubation and external ventricular CSF drainage, a permanent shunt was inserted, the edema resolved, and the patient recovered to her pretreatment condition within 10 days. The remaining metastases were treated during the first session and MR images showed the hydrocephalus resolved when all the radiated tumors had significantly decreased in size. INTERPRETATION: Care should be taken when treating with radiosurgery patients posterior fossa metastases and signs of compressed CSF pathways. Exceptionally, an acute radiation induced edema could result in a block of the CSF pathways, necessitating a surgical intervention. Prophylactic shunt insertion or hospitalization the night following the treatment should be considered.

Acute Disease↗

Can ultrasound replace dilation and curettage? A longitudinal evaluation of postmenopausal bleeding and transvaginal sonographic measurement of the endometrium as predictors of endometrial cancer.

OBJECTIVE: The purpose of this study was to evaluate postmenopausal bleeding and transvaginal sonographic measurement of endometrial thickness as predictors of endometrial cancer and atypical hyperplasia in women whose cases were followed for > or =10 years after referral for postmenopausal bleeding. STUDY DESIGN: Women (n = 394) who had postmenopausal bleeding from November 1987 to October 1990 underwent transvaginal sonographic measurement of endometrial thickness and curettage. It was possible to assess the medical records (regarding recurrence of a postmenopausal bleeding, development of endometrial cancer, and death) in 339 of the 394 women (86%) > or =10 years after referral for postmenopausal bleeding. RESULTS: Thirty-nine of the 339 women (11.5%) had endometrial cancer, and 5 women (1.5%) had atypical hyperplasia. The relative risk of endometrial cancer in women who were referred for postmenopausal bleeding was 63.9 (95% CI, 46.0-88.8); the corresponding relative risk for endometrial cancer and atypical hyperplasia together was 72.1 (95% CI, 52.8-98.5) compared with women of the same age from the general population of the same region of Sweden. No woman with an endometrial thickness of < or =4 mm was diagnosed as having endometrial cancer. The relative risk of the development of endometrial cancer in women with an endometrial thickness of >4 mm was 44.5 (95% CI, 6.5-320.1) compared with women with an endometrial thickness of < or =4 mm. The reliability of endometrial thickness (cutoff value, < or =4 mm) as a diagnostic test for endometrial cancer was assessed: Sensitivity, 100%; specificity, 60%; positive predictive value, 25%; and negative predictive value, 100%. The incidence of endometrial cancer or atypical hyperplasia in women with an intact uterus whose cases had been followed for > or =10 years was 5.8% (15/257 women) compared with 22.7% (15/66 women) in women who had < or =1 episode of recurrent bleeding. No endometrial cancer was diagnosed in women with a recurrent postmenopausal bleeding who had an endometrial thickness of < or =4 mm at the initial scan. CONCLUSION: Postmenopausal bleeding incurs a 64-fold increase risk for endometrial cancer. There was no increased risk of endometrial cancer or atypia in women who did not have recurrent bleeding, whereas women with recurrent bleeding were a high-risk group. No endometrial cancer was missed when endometrial thickness measurement (cutoff value, < or =4 mm) was used, even if the women were followed up for < or =10 years. We conclude that transvaginal sonographic scanning is an excellent tool for the determination of whether further investigation with curettage or some form of endometrial biopsy is necessary

Aged↗

Sexual conflict and cooperation in butterfly reproduction: a comparative study of polyandry and female fitness.

Most butterfly species can be characterized as capital breeders, meaning that reproductive output is strongly coupled to the amount of resources they have procured during the larval stage. Accordingly, female fecundity is generally correlated with female mass, both within and across species. However, the females of some species can be partly characterized as income breeders, in the sense that their reproductive output is dependent not only on larval-derived capital but also on resources acquired during the adult stage. These adult resources can be derived from female feeding or from male-transferred nuptial gifts. Recent studies on the within-species effects of multiple matings on female fitness show that females generally gain directly from multiple matings in terms of increased lifetime offspring production. Here, we test whether the positive effects of multiple mating on female fitness also hold at a comparative level, by conducting a laboratory study of female reproductive output in eight pierid species that differ in life-time female mating frequency. Female reproductive output, measured as cumulative egg mass divided by female mass, increased significantly with polyandry (r = 0.942, p < 0.001), demonstrating that the positive effect of mating rate on female reproductive fitness also holds between species. The positive effect of male nutrient contribution is substantial, and the per capita reproductive output is more than twice as high in the most polyandrous species as in the most monandrous ones. Hence, the positive net effect of the ejaculates is highly substantial, although males and females can have sexual interests that run counter to each other, setting the stage for sexually antagonistic coevolution, so that the various component parts of the male ejaculate-sperm, nutrients, anti-aphrodisiacs, and gonadotrophic hormones-may each correspond to a separate conflict-cooperation balance between the sexes. Two scenarios for the evolution of nuptial gifts in butterflies are discussed, one arguing that variation in larval food is the underlying factor and the other arguing that sexually antagonistic coevolution is the driving force. The two views are complementary rather than mutually exclusive, although the former hypothesis predicts that variation in female mating rate depends on variation in larval food availability, whereas the latter suggests that variation in female mating rate between species results from species-specific idiosyncrasies.

Animals↗

Risk for hemorrhage during the 2-year latency period following gamma knife radiosurgery for arteriovenous malformations.

PURPOSE: Radiosurgery does not immediately obliterate an arteriovenous malformation (AVM), and the risk for hemorrhage still persists until the AVM is occluded. There is controversy about whether this risk is altered after as compared to before radiosurgery. The aim of this paper is to study this topic further and to suggest a model to predict the risk for posttreatment hemorrhage. METHODS AND MATERIALS: The incidence of hemorrhages within the first 24 months following Gamma Knife radiosurgery was studied retrospectively among 1593 AVM patients, and was related to patient, AVM, and treatment parameters. RESULTS: Fifty-six patients experienced a hemorrhage in the latency period, representing an average annual incidence of 1.8%. The incidence of posttreatment hemorrhage was related to the patient's age, AVM volume, minimum dose, and average dose delivered to the AVM nidus. Based on these observations, an equation was defined that could quantify the probability for a posttreatment hemorrhage to occur. CONCLUSION: A model that can predict the probability for a hemorrhage within the first 24 months after radiosurgery is presented. The risk is higher for larger AVMs and for older patients, and it is lower when higher doses of radiation are used.

Adult↗

Gamma knife outcome models as a reference standard in the embolisation of cerebral arteriovenous malformations.

BACKGROUND: We sought to utilise outcome models from Gamma Knife radiosurgery (GKRS) to cerebral arteriovenous malformations (AVM) as a reference standard in assessing the clinical outcome of embolisation, thus comparing the outcomes of two different management alternatives, in the same patients. METHODS: 87 consecutive patients with 88 AVM were admitted during 1997-1999 for initial embolisation of an AVM. The clinical outcomes were recorded prospectively. Angiography under stereotactic conditions with measurement of AVM volume was performed before and after embolisation. GKRS outcome models were used to predict obliteration rate, complication rate and risk of haemorrhage before and after embolisation. The clinical outcome of embolisation followed by predicted outcome of adjunct GKRS was then compared with the predicted outcome of GKRS as the only treatment. FINDINGS: Eight patients were subjected to microcatheterisation but not to embolisation. By the end of the study period, embolisation had been terminated in 55 patients out of 80 (69%). The predicted outcome of GKRS alone was 58 obliterations and 12 complications while that of the combined management was 58 obliterations and 15 complications. The difference was not significant on the p < 0.1 level. INTERPRETATION: Volume measurement from angiography and outcome models from Gamma Knife radiosurgery are useful as a reference standard in the management of AVM. Absolute volume reduction from embolisation is most prominent for AVM > 10 ml and thus facilitates subsequent radiosurgery. For AVM < or = 10 ml, GKRS as the only treatment can be an alternative to primary embolisation, particularly if no significant volume reduction or obviously beneficial effect of targeted embolisation is expected. Further prospective studies are needed to identify subgroups in which one treatment has advantages over the other.

Adolescent↗

High-efficiency astatination of antibodies using N-iodosuccinimide as the oxidising agent in labelling of N-succinimidyl 3-(trimethylstannyl)benzoate.

Monoclonal antibodies C215, reactive with colorectal carcinomas, and MOv18, reactive with most of the ovarian carcinomas, were radiohalogenated with [211At]astatine. The radiohalogen was conjugate coupled to antibodies via the intermediate labelling reagent N-succinimidyl-3-(trimethylstannyl)benzoate (m-MeATE) in a two-step, single-pot reaction. Optimisation of the labelling of the reagent was achieved using N-iodosuccinimide, NIS, as the oxidising agent. The yields ranged from 69-95% in the labelling of 0.1-1.0 nmole of the m-MeATE precursor. Subsequent conjugation to antibodies resulted in yields of 58+/-7%. In vitro binding to tumour cells showed that the immunoreactivity of both antibodies was retained after astatine labelling.

Antibodies, Monoclonal↗

Factors associated with endometrial thickness and uterine size in a random sample of postmenopausal women.

OBJECTIVE: The objective of this study was to investigate factors possibly associated with endometrial thickness and uterine size in a random sample of postmenopausal women. STUDY DESIGN: A random sample (n = 1000) of the total population of women 45 to 80 years of age, resident in the city of Göteborg, was invited to attend for a transvaginal sonography examination. Eight hundred twenty-seven women accepted the invitation and underwent a gynecologic and a transvaginal sonography examination with measurement of endometrial thickness and uterine size. The women's weight and height were measured and a blood sample for analysis of serum estradiol and follicle-stimulating hormone was taken. The women also provided information regarding previous medical and gynecologic history, possible medication, and smoking habits. RESULTS: Five hundred fifty-nine women were postmenopausal, and 183 (33%) of the postmenopausal women were taking some form of hormonal substitution. Factors associated with endometrial thickness and uterine size were analyzed by means of univariate and stepwise multiple regression analyses. The current use of hormone replacement therapy was the most important factor associated with both endometrial thickness and all the uterine size parameters studied. The presence of fibroids was also associated with endometrial thickness. Other factors shown to be associated with uterine size were age, parity, smoking, hypertension, and the presence of diabetes mellitus. CONCLUSIONS: Several of the known risk factors for endometrial cancer were shown to be associated with endometrial thickness and uterine size parameters.

Aged↗

Is there an association between shift work and having a metabolic syndrome? Results from a population based study of 27,485 people.

OBJECTIVES: To explore how metabolic risk factors for cardiovascular disease (CVD) differ between shift workers and day workers in a defined population. Shift work has been associated with an increased risk of CVD. Risk factors and causal pathways for this association are only partly known. METHODS: A working population of 27,485 people from the Västerbotten intervention program (VIP) has been analysed. Cross sectional data, including blood sampling and questionnaires were collected in a health survey. RESULTS: Obesity was more prevalent among shift workers in all age strata of women, but only in two out of four age groups in men. Increased triglycerides (>1.7 mmol/l) were more common among two age groups of shift working women but not among men. Low concentrations of high density lipoprotein (HDL) cholesterol (men<0.9 and women<1.0 mmol/l) were present in the youngest age group of shift workers in both men and women. Impaired glucose tolerance was more often found among 60 year old women shift workers. Obesity and high triglycerides persisted as risk factors in shift working men and women after adjusting for age and socioeconomic factors, with an OR of 1.4 for obesity and 1.1 for high triglyceride concentrations. The relative risks for women working shifts versus days with one, two, and three metabolic variables were 1.06, 1.20, and 1.71, respectively. The corresponding relative risks for men were 0.99, 1.30, and 1.63, respectively. CONCLUSIONS: In this study, obesity, high triglycerides, and low concentrations of HDL cholesterol seem to cluster together more often in shift workers than in day workers, which might indicate an association between shift work and the metabolic syndrome.

Adult↗

Nuptial gifts and the use of body resources for reproduction in the green-veined white butterfly Pieris napi.

Reproduction in butterflies, as in many holometabolous insects, is usually constrained by the amount of nutrients the animals can collect as juveniles. In polyandric species the females can also supplement their larval-derived reserves with protein-rich donations, so-called nuptial gifts, delivered by the males at mating. Recent findings also indicate that females have access to nitrogen from the histolysis of flight muscles in the thorax. This field study examined how butterflies of the polyandric gift-giving species Pieris napi (Lepidoptera: Pieridae) use body resources in their reproduction and how the male donations affect the females use of stored reserves. The results support earlier studies, indicating that females use resources from the breakdown of thorax muscles to increase their reproductive potential and the results also indicate that males also use thorax material in their reproduction. The study also supports recent findings that the male donation increases the breakdown of body resources and thereby boosts the reproductive output of the female.

Animals↗

Volume measurement of cerebral arteriovenous malformations from angiography.

We designed software for measuring the volume of cerebral arteriovenous malformations from angiography and validated it against prescription volumes in radiosurgery. We aimed to create a model for the risk for complications as a function of volume, based on established outcome prediction models for Gamma Knife radiosurgery, but without the need for dose planning. We created an application for computing the volume of cerebral arteriovenous malformations from the intersection of two X-ray cones in stereotactic space. Volume measurements were compared with prescription volumes from dose planning, in phantoms and in patients treated with Gamma Knife radiosurgery for cerebral arteriovenous malformations. Previous studies of 1128 treated patients were used to calculate the risk for complication as a function of the nidus volume. In 63 patients volumes measured with either method correlated, R2 = 0.85. Volume as measured with the intersecting cone model (ICM) correlated with predicted Gamma Knife radiosurgery complication rate, R2 = 0.84. The ICM can thus be used for measurement of AVM volumes less than 10 cm3 from angiography. Outcome models from Gamma Knife radiosurgery may be applied, but with reduced exactness. Standardised AVM volume measurement is valuable for comparing outcome and for quantification of volume reduction after therapy, notably embolisation. Thus the optimal management plan may be selected in conjunction with diagnostic or therapeutic angiography.

Cerebral Angiography↗

The DopFet system: a new ultrasonic Doppler system for monitoring and characterization of fetal movement.

To enable the investigation of fetal movement in a manner similar to fetal heart rate (FHR) monitoring we have developed an apparatus (the DopFet system) that consists of a pair of miniature sensors, a 2-MHz continuous-wave directional Doppler electronic module and a laptop personal computer. One of the sensors is aimed at the fetal limbs and the other at the thorax to detect heart and upper body movements. The signals are analyzed, presented in real-time and postprocessed by software developed by us. The postprocessing software computes a number of parameters (the DopFet parameters) describing fetal movement. These parameters can be divided into two categories: parameters that describe the quantity of fetal movement (i.e., number of movements) and parameters that describe qualitative aspects of fetal movement (i.e., average movement duration). Future studies using the DopFet system will be aimed at discovering which of these parameters or combination of parameters is the best indicator of fetal well-being. We present an example of a 0.5 h recording and the results of testing on 23 volunteer mothers. These results show good sensitivity of the system compared to real-time ultrasound (US). The system detects 96% of rolling movements, 100% of flexion movements and 97% of leg movements.

Female↗

Effects of fetal and maternal breathing on the ultrasonic Doppler signal due to fetal heart movement.

Fetal heart rate (FHR) monitoring is widely used to evaluate fetal health and is based on the detection of movements of the fetal heart by Doppler ultrasound. Fetal health can also be evaluated by prolonged observation of body- and pseudo-respiratory movements using two-dimensional ultrasound. Fetal breathing movements are in particular considered to be an important indicator of fetal well being. Ultrasonic Doppler signals caused by movements of the fetal heart were analyzed in detail. The signals were acquired from five healthy fetuses. Minor changes in the insonification geometry gave rise to great variations in the aspects of successive heartbeats. The signals are shown to contain information on both maternal and fetal respiratory movements. This may facilitate the development of a simple method for fetal respiration monitoring coupled to standard FHR monitoring.

Female↗

Transvaginal ultrasonography of the endometrium in women with postmenopausal bleeding: is it always necessary to perform an endometrial biopsy?

OBJECTIVE: This study was undertaken to evaluate whether it was possible to abstain from performing an endometrial biopsy when endometrial thickness according to transvaginal ultrasonography was </=4 mm in women with postmenopausal bleeding or irregular bleeding during hormone replacement therapy. STUDY DESIGN: Transvaginal ultrasonography was performed in 361 women aged >/=50 years who were referred because of postmenopausal bleeding or irregular bleeding during hormone replacement therapy. If endometrial thickness was </=4 mm, a Papanicolaou cervical smear was performed and the woman was reexamined with transvaginal ultrasonography after 4 and 12 months. Subjects were also instructed to return if they had recurrent bleeding, in which case transvaginal ultrasonography was performed and an endometrial biopsy specimen was obtained. Women with an endometrial thickness >/=5 mm underwent either curettage or endometrial biopsy. RESULTS: One hundred sixty-three women had an endometrial thickness </=4 mm. In this group one endometrial cancer that was missed by ultrasonography was diagnosed by cervical cytologic examination and two adnexal malignancies were diagnosed by ultrasonography. Endometrial malignancy was diagnosed in 0.6% of the women with an endometrial thickness </=4 mm. Endometrial biopsy was performed because of recurrent bleeding in 6.1% of cases and because of endometrial thickening in 8.1%. No cancer or hyperplasia was subsequently diagnosed among the women with an endometrial thickness </=4 mm. Endometrial cancer was diagnosed in 18.7% of the women with an endometrial thickness >/=5 mm. The corresponding figure when atypical hyperplasia and endometrial metastases were included was 20. 2%. CONCLUSION: If the false-negative rate of endometrial biopsy techniques is taken into account, then the combination of transvaginal ultrasonography and cervical cytologic examination is an adequate form of management for women with postmenopausal bleeding or irregular bleeding during hormone replacement therapy as long as endometrial thickness is </=4 mm. A randomized prospective study is necessary to verify this finding.

Biopsy↗

Angiographic long-term follow-up data for arteriovenous malformations previously proven to be obliterated after gamma knife radiosurgery.

OBJECTIVE: To investigate whether angiograms obtained 2 years after radiosurgery, proving total arteriovenous malformation (AVM) occlusion, represent the final state of treated AVMs and adjacent normal vessels. METHODS: Angiograms were obtained for 48 patients 5 to 24 years after gamma knife radiosurgery and 4 to 17 years after the AVMs had been proven to be totally occluded after the treatment; changes in normal vessels and signs of recanalization were recorded. Ten of the patients developed clinical symptoms attributable to the AVMs or the treatment after having been declared cured, whereas the other patients did not exhibit symptoms. RESULTS: There was evidence of AVM nidi at the sites of previously occluded AVMs for two patients and of nidi adjacent to those sites for another two patients. Three of the four recurrent AVMs were associated with hemorrhaging. All patients who experienced hemorrhaging from previously occluded AVMs were < or = 14 years of age at the time of gamma knife radiosurgery. There were signs of segmental narrowing in normal vessels that had been irradiated with high doses (nine patients) or a low dose (one patient). The segmental narrowing decreased with time for four of these patients, was unchanged for four, and increased for two. These vascular changes did not produce clinical symptoms in any of the patients. CONCLUSION: There is a small possibility that AVMs may reappear after having been totally occluded after radiosurgery, especially in pediatric patients. Segmental narrowing in normal arteries after radiosurgery is a benign condition that rarely progresses and does not produce clinical symptoms.

Adolescent↗

Can the probability for obliteration after radiosurgery for arteriovenous malformations be accurately predicted?

PURPOSE: To investigate how accurate different models predict the probability for obliteration following radiosurgery for an arteriovenous malformation (AVM). METHODS AND MATERIALS: The probability for obliteration was calculated for all 838 AVMs with a known treatment outcome and treated at the Karolinska Hospital with Gamma Knife surgery 1970-1993. Four different models were used for the calculation, resulting in four different values of the probability for obliteration. The calculated prediction values were added for each model, and the total number of predicted obliteration compared to that observed in the whole patient material as well as in different subgroups. RESULTS: Three of the four models predicted the total number of obliterations accurately. In two of those three models, the accuracy of the prediction was dependent on AVM volume and treatment dose. In one model only, the prediction was accurate and independent of all investigated parameters. CONCLUSIONS: The probability for obliteration was accurately predicted by one of the models analyzed. In this model, the probability for obliteration was related to the dose to the AVM periphery only. The AVM volume had no independent impact on the probability for obliteration. There was a trend that AVMs with a central location had a better obliteration rate than predicted.

Adult↗

Summary report of the TD-3 workshop: characterization of 83 antibodies against prostate-specific antigen.

Twelve research groups participated in the ISOBM TD-3 Workshop in which the reactivity and specificity of 83 antibodies against prostate-specific antigen (PSA) were investigated. Using a variety of techniques including cross-inhibition assays, Western blotting, BIAcore, immunoradiometric assays and immunohistochemistry, the antibodies were categorized into six major groups which formed the basis for mapping onto two- and three-dimensional (2-D and 3-D) models of PSA. The overall findings of the TD-3 Workshop are summarized in this report. In agreement with all participating groups, three main antigenic domains were identified: free PSA-specific epitopes located in or close to amino acids 86-91; discontinuous epitopes specific for PSA without human kallikrein (hK2) cross-reactivity located at or close to amino acids 158-163; and continuous or linear epitopes shared between PSA and hK2 located close to amino acids 3-11. In addition, several minor and partly overlapping domains were also identified. Clearly, the characterization of antibodies from this workshop and the location of their epitopes on the 3-D model of PSA illustrate the importance of selecting appropriate antibody pairs for use in immunoassays. It is hoped that these findings and the epitope nomenclature described in this TD-3 Workshop are used as a standard for future evaluation of anti-PSA antibodies.

Antibodies, Monoclonal↗