Biomedical subjects

J Nilsson

Publications and source records attributed to J Nilsson.

At least 19 recordsLinked to original sources

PubMed2006

Core area scaling of Nd:Al-doped silica depressed clad hollow optical fiber and Q-switched laser operation at 0.9 microm.

We demonstrate a Q-switched, cladding-pumped, Nd:Al-doped silica depressed clad hollow optical fiber (DCHOF) laser, which generated up to 133 microJ of pulse energy at a repetition rate of 5 kHz and 0.9 W of average output power at a high repetition rate (>20 kHz) in a diffraction-limited beam (M(2)=1.08) at 927 nm. The laser was tunable from 919 to 935 nm. This result shows the potential of the DCHOF structure for the suppression of unwanted long-wavelength radiation in large-area cores suitable for high-power Q-switched laser operation.

Journal Article↗

PubMed2006

High-power continuous-wave cladding-pumped Raman fiber laser.

We demonstrate a high-power single-mode cladding-pumped Raman fiber laser. The Raman fiber laser consists of a 1.2 km long germanium-doped double-clad fiber in a linear cavity, which is spliced to a single-mode fiber. The laser is end pumped by a multimode erbium-ytterbium-doped fiber, which is coupled to the inner cladding of the Raman fiber. The embedded core was designed to be single mode at the Raman Stokes wavelength, and up to 10 W of power was obtained at 1660 nm from the single-mode fiber end. The laser has a slope efficiency of 67% and a threshold of 6.5 W.

Journal Article↗

PubMed2006

Risk factors for fragility fracture in middle age. A prospective population-based study of 33,000 men and women.

The incidence of fragility fractures begins to increase in middle age. We investigated prospectively risk factors for low-energy fractures in men and women, and specifically for forearm, proximal humerus, vertebral, and ankle fractures. The population-based Malmö Preventive Project consists of 22,444 men and 10,902 women, mean age 44 and 50 years, respectively, at inclusion. Baseline assessment included multiple examinations and lifestyle information. Mean follow-up was 19 and 15 years for men and women, respectively, regarding incident fractures. Fractures were ascertained from radiographic files. At least one low-energy fracture occurred in 1,262 men and 1,257 women. In men, the risk factors most strongly associated with low-energy fractures were diabetes [relative risk (RR) 2.38, confidence interval (CI) 95% 1.65-3.42] and hospitalization for mental health problems (RR 1.92, CI 95% 1.47-2.51). Factors associated with mental health and lifestyle significantly increased the fracture risk in most of the specific fracture groups: hospitalizations for mental health problems (RR 2.28-3.38), poor appetite (RR 3.05-3.43), sleep disturbances (RR 1.72-2.95), poor self-rated health (RR 1.80-1.83), and smoking (RR 1.70-2.72). In women, the risk factors most strongly associated with low-energy fractures were diabetes (RR 1.87, CI 95% 1.26-2.79) and previous fracture (RR 2.00, CI 95% 1.56-2.58). High body mass index (BMI) significantly increased the risk of proximal humerus and ankle fractures (RR 1.21-1.33) while, by contrast, lowering the risk of forearm fractures (RR 0.88, CI 95% 0.81-0.96). Risk factors for fracture in middle-aged men and women are similar but with gender differences for forearm, vertebral, proximal humerus, and hip fracture whereas risk factors for ankle fractures differ to a certain extent. The risk-factor pattern indicates a generally impaired health status, with mental health problems as a major contributor to fracture risk, particularly in men.

Adult↗

PubMed2005

High-power tunable single-frequency single-mode erbium:ytterbium codoped large-core fiber master-oscillator power amplifier source.

We present a cladding-pumped single-frequency, single-mode erbium:ytterbium codoped fiber master-oscillator power amplifier source generating up to 151 W of continuous-wave output power at 1563 nm with 33% slope efficiency and 20 dB gain. This source was also tunable and had a stable operation range of 1546 to 1566 nm at an output power level in excess of 125 W. The doped fiber exploited a large-core design for improved power handling and mitigation of stimulated Brillouin scattering. There was no sign of having stimulated Brillouin scattering even at the highest power. Despite a large core (V = 12), the output beam was nearly diffraction limited (M2 = 1.1). The source showed slight rollover at over 100 W of output power because of the onset of emission from ytterbium, centered at 1060 nm.

Journal Article↗

PubMed2005

Single-mode plane-polarized ytterbium-doped large-core fiber laser with 633-W continuous-wave output power.

We demonstrate a cladding-pumped single-mode plane-polarized ytterbium-doped fiber laser generating 633 W of continuous-wave output power at 1.1 microm with 67% slope efficiency and a polarization extinction ratio better than 16 dB. The laser is end pumped through both fiber ends and shows no evidence of roll-over, even at the highest output power, which is limited only by the available pump power.

Journal Article↗

PubMed2005

Worse survival for TP53 (p53)-mutated breast cancer patients receiving adjuvant CMF.

BACKGROUND: TP53 has been described as a prognostic factor in many malignancies, including breast cancer. Whether it also might be a predictive factor with reference to chemo- and endocrine therapy is more controversial. PATIENTS AND METHODS: We investigated relapse-free (RFS), breast cancer-corrected (BCCS) and overall survival (OS) related to TP53 status in node-positive breast cancer patients that had received polychemotherapy [cyclophosphamide, methotrexate, 5-fluorouracil (CMF)] and/or endocrine therapy (tamoxifen). Sequence analyses of the whole TP53 coding region was performed in 376 patients operated on for primary breast cancer with axillary lymph node metastases between 1984 and 1989 (median follow-up time 84 months). RESULTS: TP53 mutations were found in 105 patients (28%). We found 90 (82%) of the 110 mutations in the more frequently analysed exons 5-8, while the other 20 (18%) were located in exons 3-4 and 9-10, respectively. Univariate analyses showed TP53 to be a significant prognostic factor with regard to RFS, BCCS and OS in patients who received adjuvant CMF. CONCLUSIONS: TP53 mutations might induce resistance to certain modalities of breast cancer therapy. Sequence-determined TP53 mutation was of negative prognostic value in the total patient population and in the CMF treated patients.

Adult↗

PubMed2005

Single-frequency, single-mode, plane-polarized ytterbium-doped fiber master oscillator power amplifier source with 264 W of output power.

We present a single-frequency, single-mode, plane-polarized ytterbium-doped all-fiber master oscillator power amplifier source at 1060 nm generating 264 W of continuous-wave output power. The final-stage amplifier operated with a high gain of 19 dB and a high conversion efficiency of 68%. There was no evidence of rollover from stimulated Brillouin scattering even at the highest output power, and the maximum output was limited only by the available pump power.

Journal Article↗

PubMed2005

Emergency surgery for colonic cancer in a defined population.

BACKGROUND: The aim of this study was to identify risk factors in emergency surgery for colonic cancer in a large population and to investigate the economic impact of such surgery. METHODS: Data from the colonic cancer registry (1997-2001) of the Uppsala/Orebro Regional Oncological Centre were analysed and classified by hospital category. Some 3259 patients were included; 806 had an emergency and 2453 an elective procedure. Data for calculating effects on health economy were derived from a national case-costing register. RESULTS: Patients who had emergency surgery had more advanced tumours and a lower survival rate than those who had an elective procedure (5-year survival rate 29.8 versus 52.4 per cent; P < 0.001). There was a stage-specific difference in survival, with poorer survival both for patients with stage I and II tumours and for those with stage III tumours after emergency compared with elective surgery (P < 0.001). Emergency surgery was associated with a longer hospital stay (mean 18.0 versus 10.0 days; P < 0.001) and higher costs (relative cost 1.5 (95 per cent confidence interval 1.4 to 1.6)) compared with elective surgery. The duration of hospital stay was the strongest determinant of cost (r(2) = 0.52, P < 0.001). CONCLUSION: Emergency surgery for colonic cancer is associated with a stage-specific increase in mortality rate.

Adolescent↗

PubMed2005

Gastrointestinal complications after cardiac surgery.

BACKGROUND: Gastrointestinal complications after cardiac surgery are often difficult to diagnose, and are associated with high morbidity and mortality rates. The aim of this study was to determine risk factors for these complications. METHOD: Between 1996 and 2001 data were collected prospectively from 6119 patients who underwent 6186 cardiac surgical procedures. Data from patients who experienced major gastrointestinal complications were analysed retrospectively by univariate and multivariate analysis. RESULTS: Fifty major gastrointestinal complications were identified in 47 patients (incidence 0.8 per cent). Thirteen of these patients died within 30 days. The most common complication was upper gastrointestinal bleeding (16 patients). Intestinal ischaemia was the most lethal complication (eight of ten patients died). Abdominal surgical operations were performed in 12 patients. Multivariate analysis identified nine variables that independently predicted major gastrointestinal complications: age over 80 years, active smoker, need for preoperative inotropic support, New York Heart Association class III-IV, cardiopulmonary bypass time more than 150 min, postoperative atrial fibrillation, postoperative heart failure, reoperation for bleeding and postoperative vascular complications. CONCLUSION: Nine risk factors for the development of major gastrointestinal complications after cardiac surgery were identified. Gastrointestinal complications were often lethal but did not independently predict death within 30 days.

Aged↗

PubMed2005

Extensive immigration from compensatory hatchery releases into wild Atlantic salmon population in the Baltic sea: spatio-temporal analysis over 18 years.

Genetic homogenization has been recognized as a serious threat in an increasing number of species, including many salmonid fishes. We assessed the rate and impact of immigration from the main hatchery stocks of Atlantic salmon in the Gulf of Bothnia into one of the largest wild salmon populations in the Baltic Sea, the River Vindelälven, within a temporal framework of 18 years (from 1985-2003). We provide genetic evidence based on mtDNA and microsatellite markers, using mixed-stock analysis, that a large proportion (66%) of fin-damaged spawners (n=181) caught in the Ume/Vindelälven during 1997-2003 originated from the hatcheries in the Rivers Angermanälven, Luleälven and Ljusnan. The maximum-likelihood estimate of immigration rate from these hatcheries into the wild Vindelälven population was 0.068 (95% CI 0.021-0.128) over the studied time period (1985-2003) and reached up to a quarter (m=0.249, 95% CI 0.106-0.419) of the total population during 1993-2000. This resulted in significant (P<0.01) genetic homogenization trend between the wild Vindelälven population and hatchery stocks of the Angermanälven and Luleälven. Our results demonstrate extensive straying from geographically distant hatchery releases into wild salmon population and emphasize the genetic risks associated with current large-scale stocking practices in the Baltic Sea.

Animals↗

PubMed2005

Gene expression profiling of leukemic cell lines reveals conserved molecular signatures among subtypes with specific genetic aberrations.

Hematologic malignancies are characterized by fusion genes of biological/clinical importance. Immortalized cell lines with such aberrations are today widely used to model different aspects of leukemogenesis. Using cDNA microarrays, we determined the gene expression profiles of 40 cell lines as well as of primary leukemias harboring 11q23/MLL rearrangements, t(1;19)[TCF3/PBX1], t(12;21)[ETV6/RUNX1], t(8;21)[RUNX1/CBFA2T1], t(8;14)[IGH@/MYC], t(8;14)[TRA@/MYC], t(9;22)[BCR/ABL1], t(10;11)[PICALM/MLLT10], t(15;17)[PML/RARA], or inv(16)[CBFB/MYH11]. Unsupervised classification revealed that hematopoietic cell lines of diverse origin, but with the same primary genetic changes, segregated together, suggesting that pathogenetically important regulatory networks remain conserved despite numerous passages. Moreover, primary leukemias cosegregated with cell lines carrying identical genetic rearrangements, further supporting that critical regulatory pathways remain intact in hematopoietic cell lines. Transcriptional signatures correlating with clinical subtypes/primary genetic changes were identified and annotated based on their biological/molecular properties and chromosomal localization. Furthermore, the expression profile of tyrosine kinase-encoding genes was investigated, identifying several differentially expressed members, segregating with primary genetic changes, which may be targeted with tyrosine kinase inhibitors. The identified conserved signatures are likely to reflect regulatory networks of importance for the transforming abilities of the primary genetic changes and offer important pathogenetic insights as well as a number of targets for future rational drug design.

Acute Disease↗

PubMed2005

An outbreak of mumps in Sweden, February-April 2004.

Between 24 February and 26 April 2004, Västra Götaland county in Sweden reported 42 cases of suspected mumps. A descriptive study of the cases was undertaken. A questionnaire was administered by telephone and vaccine effectiveness was calculated using the screening method. Seventy four per cent (31/42) of the suspected cases were interviewed by telephone. Eight out of the 42 serum samples were positive or equivocal for mumps IgM by ELISA. Mumps virus genome was identified in 21/42 (50%) saliva samples. Eleven were selected for sequencing and all were confirmed to be mumps virus. Cases were predominantly from 2 small towns. Eighteen out of 19 cases that developed bilateral swelling could be linked to one small town. The median age of interviewed cases was 43 years (range 5 to 88). Six cases were admitted to hospital, 5 of which were older than 30 years. The highest incidence occurred in the 35 to 44 years age group. Vaccine effectiveness was estimated to be 65% for 1 dose and 91% for 2 doses. This descriptive study shows the increasing age of mumps cases with increasing vaccine coverage. Vaccine effectiveness was particularly high for 2 doses. Second-dose uptake must be ensured, as primary vaccine failure is well documented in mumps. Stronger precautions must be taken to avoid pools of susceptible older individuals accumulating due to the increased risk of complications.

Adolescent↗

PubMed2004

Semicarbazide-sensitive amine oxidase in transgenic mice with diabetes.

Semicarbazide-sensitive amine oxidase (SSAO) activity in plasma is increased in diabetes, and in particular, in diabetic patients with vascular complications. It has been speculated that SSAO is involved in the development of such complications due to the production of cytotoxic compounds. In this work, we have induced diabetes in a previously described mouse-model, overexpressing SSAO in smooth muscle cells. SSAO activity was estimated as well as expression of the endogenous mouse gene and human transgene using real-time PCR. Diabetes induced an increase in SSAO activity in serum, kidney, and adipose tissue of transgenic animals. An inverse correlation between SSAO activity and mouse SSAO mRNA levels was observed in transgenic animals with diabetes. These results further support the suggestion of a negative feedback control of the SSAO gene expression. The increased SSAO activity in diabetes is most likely dependent on post-transcriptional modifications or activation of existing inactive enzyme molecules.

Adipose Tissue↗

PubMed2004

Colorectal cancer screening with flexible sigmoidoscopy-participants' experiences and technical feasibility.

AIM: To evaluate tolerability and technical feasibility of colorectal cancer screening with flexible sigmoidoscopy. METHODS: One thousand men and women aged 59-61 years, randomly selected from the population register of Uppsala, Sweden, were invited by mail. After random allocation, half of them were called up by a nurse (group 1), while the other half were asked to call themselves (group 2) to book a sigmoidoscopy. After the examination, the participants anonymously answered a questionnaire about their subjective experiences. Endoscopists and their assisting nurse filled out structured forms documenting various technical aspects including an estimation of the subjects' discomfort. RESULTS: Four hundred and sixty-nine subjects participated. Mean intubation depth was 59 cm (range 28-60) and mean duration 5.8 min (range 2-23). On average, participants reported low degrees of discomfort and feeling of exposure, but 19 and 27% rated pain and distension, respectively, on the upper half of a visual analogue scale (VAS). Most subjects found the duration acceptable. Patient discomfort, as appraised by the endoscopists, was lower in men than in women, positively linked to duration of the procedure, but inversely associated with intubation distance. However, the overall differences between strata of participants were small. Among self-reported variables, group 1 and 2 differed significantly only with regard to 'other discomfort'. All but six subjects would accept a repeat examination. Failures, resulting in incomplete examinations, occurred in 14 subjects. CONCLUSIONS: Flexible sigmoidoscopy is generally well tolerated and technically feasible in screening for colorectal cancer. A more personalised invitation did not have any important effects on the subjective experience.

Colorectal Neoplasms↗

PubMed2004

Kin-biased distribution in brown trout: an effect of redd location or kin recognition?

A wide range of animals have been reported to show kin-biased behaviours, such as reduced aggressiveness and increased food sharing among relatives. However, less is known about whether wild animals also associate with relatives under natural conditions, which is a prerequisite to facilitate kin-biased behaviours and hence kin selection. We tested, by means of microsatellite polymorphism, correlations between pair-wise relatedness and pair-wise metric distance in wild brown trout (Salmo trutta L.) under natural conditions in two streams. Our data show that young-of-the-year as well as older trout found close together also had a higher genetic relatedness in one of the two streams, whereas no relationship was found in the other stream. Very few half and full siblings were found in the second stream and under these conditions it is unlikely that kin-biased behaviours will receive positive selection. We discuss the underlying mechanisms for the observed structure and we specifically address the issue of whether the grouping of related individuals could reflect dispersal from the same spawning redds, or if it reflects active association with relatives, possibly conferring kin-selected advantages.

Animals↗

PubMed2004

The Scandinavian Sarcoma Group Skeletal Metastasis Register. Survival after surgery for bone metastases in the pelvis and extremities.

INTRODUCTION: The assessment of the prognosis for the individual patient is important for the choice of surgical treatment of skeletal metastases. In 1999 the Scandinavian Sarcoma Group (SSG) initiated the Skeletal Metastasis Register as a multicentric, prospective study to provide a scientific basis for treatment recommendations. To improve prognostication we analyzed the survival of patients with skeletal metastases surgically treated at 9 SSG centres. PATIENTS AND METHODS: 460 patients with an average age of 64 years underwent 501 operations for non-spinal skeletal metastases. 7% were operated for more than one metastasis. Carcinoma of the breast, prostate, kidney and lung were the dominating primary tumors. RESULTS: The survival rate was 0.4 at 1 year, 0.3 at 2 years and 0.2 at 3 years. Univariate analysis showed that survival was related to bone localization, skeletal metastatic load, presence of visceral metastases, Karnofsky performance score, primary tumor type, presence of a complete pathological fracture and preoperative hemoglobin content. Multivariate regression analysis showed that pathological fracture, visceral metastases, haemoglobin content < 7 mmol/L and lung cancer were negative prognostic factors for survival. Myeloma was the sole positive prognostic factor for survival.

Bone Neoplasms↗

PubMed2004

Onychomycosis in Denmark: prevalence of fungal nail infection in general practice.

The study was initiated in order to get knowledge of the frequency of onychomycosis in patients visiting general practitioners in Denmark. A study design was using a display showing photos of abnormal nails including fungal infection, a clinical examination and a questionnaire. The practitioners obtained nail material. Direct microscopy and culture as well as histopathology, were carried out blindly in two different mycological laboratories. A number of 8546 patients were seen during the 6 months of the study, 5755 (67.3%) took part in the investigation. Clinical abnormal nails were observed in 948 (16.5%) patients, 52% males and 48% females, aged 18-92, mean 55 years old. Onychomycosis caused by dermatophytes were found in 238 (4.1%) and by Candida albicans in 45 (0.8%). Trichosporon cutaneum and Scopulariopsis brevicaulis were isolated each in 15 cases as single cultures. Onychomycosis, was typically seen in toenails as the distal-lateral type in males more than 40 years old. Predisposing factors were familiar dermatophytosis (22%), trauma (16.9%), diabetes mellitus (6.7%) and peripheral circulatory insufficiency (5.9%).

Adult↗

PubMed2004

The circular stapling device as a risk factor for anastomotic leakage.

AIM: To investigate the relation between the type of circular stapler and anastomotic leak in rectal cancer surgery. BACKGROUND: During the past decades results from rectal cancer surgery have improved considerably regarding risk of local recurrence and survival. Two main paradigm changes are considered to be the cause for this: the introduction of total mesorectal excision (TME) and the increasing use of radiotherapy. However, rectal cancer surgery is associated with an unacceptably high frequency of complications of which anastomotic leak is one of the most severe ones. The hypothesis was raised that the choice of stapler influenced the leakage rates. METHODS: A questionnaire was sent to all departments of surgery (n = 66) performing rectal cancer surgery in Sweden to determine the choice of circular stapler when performing anterior resection for rectal cancer. These data were linked to the Swedish Rectal Cancer Registry for the period 1995-99. RESULTS: A total of 3316 patients had an anterior resection. The choice of circular stapling device was determined in 70% of the cases. When stapler A was used, the leakage rate was 11% whereas it was 7% when stapler B was used (P = 0.0039). In the cases where it was impossible to determine which stapler had been used the leakage rate was 8%. CONCLUSION: Quality control is an important part of medicine and the present study suggests that it also must include surgical instruments. A prospective randomised study is needed to confirm the results.

Adult↗