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Biomedical subjects

G Aström

Publications and source records attributed to G Aström.

At least 19 recordsLinked to original sources
PubMed2005

Chemical-shift micro-imaging of subcutaneous lesions.

A chemical-shift imaging technique was used for the study of small subcutaneous lesions. This study concerns micro-imaging of two females suffering from a tenosynovial giant cell tumor and an epidermal cyst. High-resolution water, fat and chemical-shift artifact-free images were obtained on a whole-body MR unit (1.5 T) equipped with a 23-mm microscopy surface coil and standard gradients (23 mT/m). A significant improvement in signal-to-noise ratio was achieved by reducing the receiver bandwidth to values below +/-10 kHz. The image data sets were acquired with resolution 0.1 x 0.13 mm in the plane, slice thickness 0.5 mm and with acquisition time less than 3 min. Spatial resolution, fat suppression, image texture and edge delineation were improved on spectroscopic images compared with those on conventional MR images.

Adult↗
PubMed2005

Differential function of the alpha2A-adrenoceptor and Phosphodiesterase-3B in human adipocytes of different origin.

OBJECTIVE: Human adipocytes can be obtained in vitro by differentiation of human preadipocytes or mesenchymal stem cells (hMSC). Although functionally similar to freshly isolated cells, no detailed comparison of the different cell types has been performed. The antilipolytic alpha2A-adrenoceptor (AR) and the cAMP-degrading enzyme Phosphodiesterase-3B (PDE3B) have been implicated in the fine-tuning of lipolysis but little is known regarding their role in human adipocytes nor whether their expression and/or function differs in fat cells from different precursors. METHODS: The effects of alpha2A-AR and PDE3B inhibition in mature adipocytes was determined and compared to that in differentiated preadipocytes and hMSC-derived fat cells. Gene expression was determined by real-time PCR and protein expression by Western blot. RESULTS: Noradrenaline (NA) stimulated lipolysis in preadipocytes and mature adipocytes but markedly reduced lipolysis in differentiated hMSC derived-adipocytes. This was due to a potent stimulation of alpha2A-AR since co-incubation with NA and the alpha2-AR-inhibitor yohimbine restored NA-induced lipolysis. The order of Yohimbine response was hMSC>preadipocytes>mature adipocytes. Although alpha2-AR mRNA expression was highest in mature adipocytes there was no difference in alpha2A-AR protein levels between the cell types. In contrast, Galphai2 mRNA and protein expression was significantly higher in MSC-derived adipocytes, suggesting that differences in the response to alpha2A-AR inhibition reside at the postreceptor level. Incubation with the cAMP-analog 8-bromo(8b) cAMP increased lipolysis in hMSC-derived fat cells while co-incubation with the PDE3-specific inhibitor OPC3911 did not alter the lipolytic effect. In contrast, OPC3911 increased 8bcAMP-induced lipolysis significantly in preadipocytes and mature adipocytes. The response to PDE3B inhibition was; mature adipocytes>preadipocytes>hMSC a finding that correlated significantly with both PDE3B mRNA expression and enzymatic activity. CONCLUSION: Although differentiated adipocytes of different origins display similar functional characteristics there are important differences in the regulation of lipolysis with a marked alpha2A-AR and less pronounced PDE3B effect in fat cells from MSCs.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed2002

Nicotinamide prevents the long-term effects of perinatal asphyxia on basal ganglia monoamine systems in the rat.

Asphyxia during birth can cause gross brain damage, but also subtle perturbations expressed as biochemical or motor deficits with late onset in life. Thus, it has been shown that brain dopamine levels can be increased or decreased depending upon the severity of the insult, and the region where the levels are determined. In this study, perinatal asphyxia was evoked by immersing pup-containing uterus horns removed by hysterectomy in a water bath at 37 degrees C for various periods of time from 0 to 20 min. After the insult, the pups were delivered, given to surrogate mothers, treated with nicotinamide, further observed and finally, 4 weeks later, killed for monoamine biochemistry of tissue samples taken from substantia nigra, neostriatum and nucleus accumbens. The main effect of perinatal asphyxia was a decrease in dopamine and metabolite levels in nucleus accumbens, and a paradoxical increase in the substantia nigra. Nicotinamide (100 mg/kg i.p., once a day for 3 days, beginning 24 h after the perinatal asphyctic insult) prevented the effect of asphyxia in nucleus accumbens. Furthermore, striatal dopamine levels were increased by nicotinamide in asphyctic animals. No apparent changes were observed in substantia nigra. A prominent unexpected effect of perinatal asphyxia alone was on the levels of the metabolite of 5-hydroxytryptamine, 5-hydroxyindoleacetic acid (5-HIAA), which were increased in substantia nigra and decreased in both neostriatum and accumbens. However, nicotinamide increased 5-HIAA levels in all regions, which appeared to be related to the extent of the asphyctic insult. These results suggest that nicotinamide is a useful treatment against the long-term consequences produced by perinatal asphyxia on brain monoamine systems, and that there is a therapeutic window following the insult, providing a therapeutic opportunity to protect the brain.

Animals↗
PubMed2001

Spectroscopic imaging of bone marrow composition in vertebral bodies.

The proton spectroscopic imaging technique that uses read gradient during acquisition was used for the measurement of the proton spectra in the lumbar and thoracic part of the spine of a patient with breast cancer without known skeletal metastases. The bone marrow fat/water ratios were evaluated in the same location before and after chemotherapy treatment. The results were corrected for relaxation effects. The fat/water ratios showed a significant increase as a consequence of the bone marrow degradation process due to chemotherapy. The proposed spectroscopic imaging technique offers rapid acquisition of proton spectra from large volumes of the vertebral bodies.

Adipose Tissue↗
PubMed2001

High-resolution spectroscopic imaging of the human skin.

High-resolution water, fat and chemical shift artefact-free images of different areas of the skin were obtained on a whole-body MR unit (1.5 T) with commercial receiver surface coil with a diameter of 25 mm and high-power gradients (23 mT/m). Sufficient signal-to-noise ratio was achieved by lowering receiver bandwidth to +/-10 kHz or lower and shortening the echo time to 11 (13) ms. Spectroscopic image data sets were acquired with resolution 0.102 x 0.133 mm in plane and slice thickness 0.5 mm. The results demonstrate that it is possible to produce high-quality water and fat micro-images of the skin layers using only a few chemical shift encoding steps in a clinically reasonable time (approximately 2 minutes per slice).

Adipose Tissue↗
PubMed2001

A care policy and its implementation.

Chief physicians, nurse managers and head nurses (n = 50) in hospital care and primary health care in Västerbotten, Sweden, were interviewed to explore their views on adopting and implementing a new care policy. The results indicated agreement among the respondents concerning the values of the care policy and its adaptability to the health-care system. More respondents in hospital care than in primary health care expressed a positive view (63%, respectively 55%), reported involvement in the implementation process (64%, respectively 35%) and planned or ongoing activities (63%, respectively 45%). Obstacles in the implementation process due to a frustrated situation and barriers between professional groups were, however, expressed by 67% of the respondents, more among the respondents in primary health care than among those in hospital care (75%, respectively 62%). Divergent views among respondents working in the same department were seen in both hospital care and primary health care. The findings indicated demands for further efforts if the implementation is to move on from its early stages, especially in primary health care.

Attitude of Health Personnel↗
PubMed2001

Endoanal ultrasound or magnetic resonance imaging for preoperative assessment of anal fistula: a comparative study.

OBJECTIVE: To compare endoanal ultrasound (EUS) with a 10-MHz probe vs. bodycoil magnetic resonance imaging (MRI) in the preoperative evaluation of anal fistula. SUBJECTS AND METHODS: 23 patients with fistula in the anal region underwent preoperative 0.5 T bodycoil MRI and 10 MHz EUS which included probing in 6 patients. The results of the EUS and MRI were compared against the surgical findings as a reference method. RESULTS: In classification of the primary tract there was agreement between EUS and surgical findings in 14 (61%) and between MRI and surgery in 11 (48%). Concerning the presence of an internal opening the corresponding figures were 17 (74%) and 10 (43%) and in judging the presence of an extension or an abscess 15 (65%) vs. 11 (48%), respectively. In three out of eight patients with nonhealing or recurrence after surgery preoperative imaging had shown an extension and/or an abscess that was not identified by the surgeon. CONCLUSION: EUS, sometimes complemented with probing, is well comparable to bodycoil MRI in classifying and describing the topography of an anal fistula.

Journal Article↗
PubMed2001

Diagnosis of a patient with oncogenic osteomalacia using a phosphate uptake bioassay of serum and magnetic resonance imaging.

A previously healthy man with no family history of fractures presented with muscle pain, back pain and height loss. Investigations revealed hypophosphataemia, phosphaturia, undetectable serum 1,25-dihydroxyvitamin D and severe osteomalacia on bone biopsy, suggestive of a diagnosis of oncogenic osteomalacia. Thorough physical examination did not locate a tumour. Support for the diagnosis was obtained by detection of phosphate uptake inhibitory activity in a blinded sample of the patient's serum using a renal cell bioassay. On the basis of detection of this bioactivity, a total body magnetic resonance (MR) examination was performed. A small tumour was located in the right leg. Removal of the tumour resulted in the rapid reversal of symptoms and the abnormal biochemistry typical of oncogenic osteomalacia. Inhibitory activity was also demonstrated using the bioassay in serum from two other patients with confirmed or presumptive oncogenic osteomalacia, but not in serum from two patients with hypophosphataemia of other origin. This is the first case to be reported in which the diagnosis of oncogenic osteomalacia was assisted by demonstration of inhibitory activity of the patient's serum in a renal cell phosphate bioassay that provided an impetus for total body MR imaging.

Adult↗
PubMed2000

Evaluation of new sclerotic bone metastases in breast cancer patients during treatment.

PURPOSE: According to the World Health Organization (WHO) criteria for response of bone metastases to therapy, new lesions indicate progressive disease. We intended to prove that a new sclerotic lesion on conventional radiography may also be a sign of a positive therapeutic response in a previously undetectable lytic metastasis. MATERIAL AND METHODS: In a previous placebo-controlled clinical trial of clodronate (Ostac) therapy, 139 breast cancer patients with bone metastases underwent both conventional radiography and bone scan every 6 months for 2 years with 99mTc before and during clodronate treatment. WHO criteria were applied for therapy response evaluation. RESULTS: In 24 patients, 52 new sclerotic lesions observed during therapy were selected for re-evaluation of conventional radiographs and bone scans. In 8 of the 24 patients, 17 of 52 new sclerotic lesions (33%) had showed positive uptake on previous bone scans. These lesions were possibly misinterpreted as new when applying WHO criteria. CONCLUSION: For better assessment of new sclerotic lesions during treatment, more sensitive techniques, e.g. bone scan, are needed as a complement to conventional radiography.

Adult↗
PubMed1999

Use of novel bone biopsy system to study molecular effects of growth hormone in human bone--a pilot study.

In this study, we have examined whether a novel bone biopsy system combined with reverse transcription-polymerase chain reaction (RT-PCR) or differential display PCR (ddPCR) can be used to detect specific mRNAs induced by growth hormone (GH) in human bone. In a 58-year-old man with complete GH deficiency as a result of empty sella, bone biopsies were taken before, and 5 and 24 h after administration of 24 recombinant human GH. Insulin-like growth factor binding protein-3 (IGFBP-3) mRNA levels in this patient, measured in a semiquantitative RT-PCR assay, increased about 40% 24 h after GH administration. This increase was not seen in a healthy control who did not receive GH, suggesting that the increase was an effect of GH rather than of the biopsy itself. Several differentially expressed mRNAs were detected by ddPCR. Thus, this pilot study suggests that our novel bone biopsy system may be suitable for in vivo studies of the molecular effects of substances with essential functions in human bone.

Base Sequence↗
PubMed1997

Assessment of suspected bone metastases. CT with and without clinical information compared to CT-guided bone biopsy.

PURPOSE: To evaluate the role of CT with and without clinical information as compared to CT-guided bone biopsy in the assessment of suspected bone metastases. MATERIAL AND METHODS: The study comprised 51 consecutive patients with suspected bone metastases who had undergone CT-guided bone biopsies with an eccentric drill system. CT of the targets, clinical information, and histopathology were scored separately as malignant, uncertain or benign. The results of CT alone and CT in combination with clinical information were compared to the results of histopathology. RESULTS: Histopathology diagnosed 45/51 lesions (88%), 23 as malignant and 22 as benign. CT correctly depicted 17 of these 23 malignant lesions. The remaining 6 malignant lesions were CT-scored as uncertain (n = 5) or benign (n = 1). CT correctly depicted only 3 of the 22 benign lesions. The remaining 19 benign lesions were CT-scored as malignant (n = 2) or uncertain (n = 17). When uncertain CT scores were combined with clinical scores, the true-positive and true-negative results for malignancy increased from 44% to 82%. CONCLUSION: In most cases, CT in combination with clinical information gives enough information about the nature-malignant or benign-of a skeletal lesion. In uncertain cases, diagnostic accuracy can be improved by means of CT-guided bone biopsy.

Adolescent↗
PubMed1997

Respiratory burst activity of phagocytic cells isolated from the mammary glands and blood of camels (Camelus bactrianus).

The oxidative burst activity of phagocytic cells isolated from camel blood and mammary glands was studied using a chemiluminescence (Cl) assay. The polymorphonuclear leucocytes (PMNL) isolated from camel blood mounted a luminol-dependent Cl response upon stimulation with opsonized zymosan or opsonized Staphylococcus aureus. These responses showed an overall similarity to those described in other mammalian species. The leucocytes isolated from the mammary glands mounted Cl responses similar to those observed with blood PMNL but to a lower magnitude. Like the Cl responses of blood cells, the Cl responses induced by mammary gland leucocytes were associated with degranulation and the release of lysosomal enzymes such as myeloperoxidase (MPO).

Acridines↗
PubMed1996

Dihydrotestosterone and testosterone levels in men screened for prostate cancer: a study of a randomized population.

OBJECTIVE: To investigate the possible relationship between serum levels of prostate specific antigen (PSA), dihydrotestosterone (DHT), testosterone, sexual-hormone binding globulin (SHBG) and tumour stage, grade and ploidy in 65 cases of prostate cancer diagnosed in a screening study compared to 130 controls from the same population. PATIENTS, SUBJECTS AND METHODS: From a population of 26,602 men between the ages of 55 and 70 years, 2400 were selected randomly and invited to undergo screening for prostate cancer using a digital rectal examination, transrectal ultrasonography and PSA analysis. Among the 1782 attendees, 65 cases of prostate cancer were diagnosed. Each case was matched with two control subjects of similar age and prostate volume from the screening population. Frozen serum samples were analysed for PSA, DHT, testosterone and SHBG, and compared to the diagnosis and tumour stage, grade and ploidy. Comparisons between these variables, and multivariate and regression analyses were performed. RESULTS: There were significant differences in PSA level with all variables except tumour ploidy. DHT levels were slightly lower in patients with prostate cancer but the difference was not statistically significant. There was a trend towards lower DHT values in more advanced tumours and the difference for T-stages was close to statistical significance (P = 0.059). Testosterone levels were lower in patients with cancer than in the control group, but the differences were not significant. There was no correlation between testosterone levels, tumour stage and ploidy, but the differences in testosterone level in tumours of a low grade of differentiation compared to those with intermediate and high grade was nearly significant (P = 0.058). The testosterone/DHT ratio tended to be higher in patients with more advanced tumours. SHBG levels were lower in patients with cancer than in controls but the differences were not statistically significant. There were no systematic variations of tumour stage, grade and ploidy. Multivariate analysis showed that if the PSA level was known, then DHT, testosterone or SHBG added no further information concerning diagnosis, stage, grade or ploidy. Regression analysis on T-stage, PSA level and DHT showed an inverse linear relationship between PSA and DHT for stage T-3 (P = 0.035), but there was no relationship between PSA and testosterone. CONCLUSION: PSA was of value in discriminating between cases and controls and between various tumour stages and grades, but no statistically significant correlation was found for ploidy. If PSA level was known, no other variable added information in individual cases. Within a group, DHT levels tended to be lower among cases and in those with more advanced tumours. There was an inverse relationship between tumour volume, as defined by PSA level, and 5 alpha-reductase activity, as defined by DHT level, and the testosterone/DHT ratio. This trend was most obvious with T-stage. No systematic variation were found in the levels of testosterone or SHBG.

Aged↗
PubMed1995

A caprine experimental model for studies on inflammation.

A new experimental model for in vivo studies on local inflammation in the goat is presented. The teat and udder cisterns were separated by a surgical procedure, resulting in the teat cistern being an isolated pouch which is easily accessible through the teat canal and suitable for experimental studies. The surgery was consistently successful in closing the passage and no post-surgical complications were observed. The model was applied to a study of the inflammatory response induced by infusion of Salmonella endotoxin. A marked response was observed as measured by the accumulation of leukocytes, serum albumin and N-acetyl-beta-D-glucosaminidase (NAGase) in the test cistern. An initial increase in serum albumin, indicating an increase in the epithelial permeability, was observed from 1.5 h after endotoxin infusion. Approximately 0.5 h later, the cell count started to increase, reaching its peak level 3 h after infusion. The NAGase concentration was closely correlated with the cell count. The model provides new possibilities for in vivo studies on local inflammation and fulfils many of the requirements of an inflammatory model; for example, it allows non-traumatic repeated samplings from the same animal. The goat is a suitable experimental animal for many studies and, as each goat has two teats, intra-goat comparisons can be performed.

Acetylglucosaminidase↗
PubMed1995

When the severely ill elderly patient refuses food. Ethical reasoning among nurses.

Forty registered nurses (RNs) regarded as "good and experienced" in either cancer or dementia care, were asked about their decision to feed or not feed a severely ill elderly woman (a hypothetical case). In order to compare ethical reasoning in the two groups of nurses and to illuminate what it means to RNs to face a situation where the patients can/cannot decide for themselves, a phenomenological hermeneutic approach was used for the analysis. Both groups saw themselves as the advocate for their patients but in different ways. The RNs who talked about a mentally alert patient emphasized that they encouraged their patient to speak up for herself, while the RNs who talked about a severely demented patient emphasized that they tried very hard to interpret their patient's vague and unclear communicative cues and to act as her advocate, especially in relation to physicians. Transcending experiences of dying relatives and patients as well as role models helped them to achieve their ambition of putting themselves in the patient's shoes in order to respect and understand her or his wish and/or what was best for them. The majority of RNs strongly rejected active euthanasia.

Adult↗
PubMed1995

Nurses' skills in managing ethically difficult care situations: interpretation of nurses' narratives.

A total of 18 good nurses experienced in the care of cancer patients were asked to describe care situations where it had been difficult to know what was 'the right and good' thing to do for the patient. The purpose of the study was to throw light on how they disclosed themselves in managing ethically difficult care situations; to elucidate the nurse as a part of the concrete care situation. A phenomenological hermeneutic interpretation disclosed the use of paradigm cases, placing in opposition to each other negative and positive outcomes, limiting and liberating maxims, and reserved and open approaches, on the part of nurses with limited versus extensive skills in managing ethically difficult care situations. These patterns were interpreted as revealing psychological defences. The study stresses the importance of recurrent education in nursing and nursing ethics, and of individual support.

Adult↗
PubMed1995

MR imaging of multiple myeloma in tumour mass measurement at diagnosis and during treatment.

The bone marrow of the spine, pelvis and proximal femora was examined with MR imaging at diagnosis in 30 cases of multiple myeloma (MM), and during treatment on 69 occasions. The MR pattern was normal, focal or diffuse and correlated to stage. A tumour mass index (TMI) was calculated by estimating the total myeloma mass visualised at MR imaging. The TMI correlated significantly with stage, lytic bone lesions, serum calcium, serum beta-2-microglobulin and survival. No abnormalities were seen at MR investigation in 4 of 6 patients classified as stage II because of osteoporosis only. Therapy efficacy evaluation with MR imaging corresponded to clinical evaluation on 54 of the 69 occasions. MR examination of bone marrow in MM patients can be used for tumour mass assessment, both at diagnosis and during follow-up. Valuable information can be obtained when the tumour mass is difficult to estimate using clinical criteria, e.g. in non-secretory MM or when osteoporosis is the only variable indicating an increase in the tumour mass.

Aged↗