Biomedical subjects

A Rydh

Publications and source records attributed to A Rydh.

10 recordsLinked to original sources

PubMed2001

Strong vortex liquid correlation from multiterminal measurements on untwinned YBa2Cu3O(7-delta) single crystals.

Multiterminal transport measurements indicating a strongly correlated vortex liquid above the first order melting transition in untwinned YBa2Cu3O(7--delta) single crystals are presented. The correlation is found to be surprisingly stable for different weak variations of point disorder. We investigate the differences between intervortex and intravortex correlations in different contact geometries. The results are in agreement with the local conductivity model, with zero resistivity along straight vortex line segments.

Journal Article↗

PubMed2001

Radioimmunoscintigraphy using an anti-prostate monoclonal antibody (E4): a dosimetric evaluation.

The aim of this study was to evaluate different strategies to increase the tumour radiation dose for experimental radioimmunotherapy using 125I-labelled monoclonal antibody (MAb) E4 in a nude mice model xenografted with DU-145 tumours. The effects from a single injection of the 125I-labelled MAb E4, the same total amount of radiolabelled MAb E4 divided into three repeated injections, and the effect of pre-targeting with non-labelled MAb E4 for reducing the amount of shed antigen were investigated. Based on repetitive quantitative radioimmunoscintigraphies, calculation of the tumour radiation dose delivered from the 125I-nuclide was performed for each strategy. The single injection strategy without pretargeting rendered the highest mean tumour radiation dose, i.e. 0.23 Gy/MBq. Pretargeting with non-labelled MAb E4 before a single injection of [125I]E4 resulted in a slightly lower mean tumour radiation dose, i.e. 0.19 Gy/MBq, compared to the single injection alone. An even lower mean tumour radiation dose, i.e. 0.14 Gy/MBq, was obtained when the same total administered amount of activity was divided into three separate injections given in 10-day intervals. We concluded that the single injection strategy is the most efficient when using MAb E4 in this tumour model. The tumour radiation doses were not increased by dividing the same amount of activity into three injections or by pretargeting with non-labelled MAb E4.

Animals↗

PubMed2000

Quantitative bone scintigraphy. A methodological evaluation in prostate cancer.

PURPOSE: To evaluate a simple method for quantification of focal activity in bone scintigraphy (BS). MATERIAL AND METHODS: The gamma camera was calibrated using a phantom. Quantitative bone scintigraphy (QBS) was performed on 11 men recently diagnosed with prostate cancer (PCa), for whom routine BS showed involvement of the skeleton. Following endocrine therapy for 4 to 8 months, a second QBS was performed. Changes in QBS values were then compared to changes in serum levels of prostate-specific antigen (PSA). RESULTS: PSA response indicating regression of PCa was accompanied by a decrease in the QBS value in 8 of the 11 patients. The overall mean error of the QBS values was 15%. CONCLUSION: QBS according to this method is a relatively simple procedure that might contribute to objective evaluation of therapeutic effects in skeletal metastases, although its validity must be tested in a larger clinical material.

Aged↗

PubMed1999

Predictive value of prostate-specific antigen, tumour stage and tumour grade for the outcome of bone scintigraphy in patients with newly diagnosed prostate cancer.

OBJECTIVE: In order to evaluate the negative predictive value of a low prostate-specific antigen (PSA) for a positive bone scan, we performed a retrospective study in a patient material from the Umea region in Northern Sweden. We also evaluated whether different tumour grades could influence this predictive value. MATERIAL AND METHODS: Four-hundred-and-forty-six patients of newly diagnosed prostate cancer were reviewed. We analysed different levels of PSA, tumour grade, tumour stage and combinations of these parameters for their use in making a positive bone scintigraphy (BS) prediction. RESULTS: Among 214 patients with PSA <20 ng/ml, 9 showed a positive BS. When tumours of grades 2 and 3 were excluded, the number of positive BS predictions decreased to 6. For 350 of these 446 patients, a classification according to TNM was available; 162 of these 350 had a PSA value <20 ng/ml, and when this group comprised only small and well-differentiated tumours (T1-2, G1), only one of the remaining 81 patients had a positive BS result. CONCLUSIONS: We conclude that in most patients with small and well-differentiated tumours (T1-2, G1) and PSA <20, BS staging need not be carried out.

Aged↗

PubMed1999

Radioimmunotherapy of DU-145 tumours in nude mice--a pilot study with E4, a novel monoclonal antibody against prostate cancer.

The anti-tumour effect of the 131I-labelled antiprostate monoclonal antibody (MAb) E4 was studied in an experimental model with 41 nude mice, subcutaneously xenografted with a human prostate cancer cell line (DU-145). The mice were divided into four study groups, i.e. one receiving single and another repeated injections of the radiolabelled MAb. A third group was injected with non-labelled MAb, and the fourth served as an untreated control group. The tumour volumes increased similarly in all groups during the 27-day observation period. The tumour tissue was morphologically disintegrated in the group that received repeated radioimmunotherapy (RIT). The tumours from this group contained large fluid-filled cystic parts and demonstrated pronounced cellular and subcellular polymorphism in the remaining viable tumour tissue. The untreated control tumours and single therapy tumours remained solid. The proportion of the total tumour volume that consisted of viable tumour cells, as determined by morphometric techniques, was significantly lower in the 131I-E4-treated groups. The use of 131I-labelled E4 MAb has thus demonstrated a promising therapeutic potential.

Animals↗

PubMed1998

Serum amyloid P component scintigraphy in familial amyloid polyneuropathy: regression of visceral amyloid following liver transplantation.

Familial amyloid polyneuropathy (FAP) associated with transthyretin (TTR) mutations is the commonest type of hereditary amyloidosis. Plasma TTR is produced almost exclusively in the liver and orthotopic liver transplantation is the only available treatment, although the clinical outcome varies. Serum amyloid P component (SAP) scintigraphy is a method for identifying and quantitatively monitoring amyloid deposits in vivo, but it has not previously been used to study the outcome of visceral amyloid deposits in FAP following liver transplantation. Whole body scintigraphy following injection of iodine-123 labelled SAP was performed in 17 patients with FAP associated with TTR Met30 and in five asymptomatic gene carriers. Follow-up studies were performed in ten patients, eight of whom had undergone orthotopic liver transplantation 1-5 years beforehand. There was abnormal uptake of 123I-SAP in all FAP patients, including the kidneys in each case, the spleen in five cases and the adrenal glands in three cases. Renal amyloid deposits were also present in three of the asymptomatic carriers. Follow-up studies 1-5 years after liver transplantation showed that there had been substantial regression of the visceral amyloid deposits in two patients and modest improvement in three cases. The amyloid deposits were unchanged in two patients. In conclusion, 123I-SAP scintigraphy identified unsuspected visceral amyloid in each patient with FAP due to TTR Met30. The universal presence of renal amyloid probably underlies the high frequency of renal failure that occurs in FAP following liver transplantation. The variable capacity of patients to mobilise amyloid deposits following liver transplantation may contribute to their long-term clinical outcome.

Adult↗

PubMed1997

Radioimmunoscintigraphy with a novel monoclonal antiprostate antibody (E4): an experimental study in nude mice.

BACKGROUND: Prostate cancer is one of the leading causes of death among men, despite achievements in diagnosis and therapy. Radioimmunolocalization and radioimmunotherapy of malignant tumors have demonstrated increasing potential and may become useful tools in the management of prostate cancer. METHODS: Nude mice were inoculated subcutaneously with cells from the poorly differentiated human prostate cancer cell line DU-145. The intact monoclonal antibody (MoAb) E4 and an intact anticytokeratin-8 MoAb, TS1, used for comparison were labeled with 125I and injected intraperitoneally (i.p.) in the mice. Repetitive quantitative scintigraphic recordings were performed during 1 month. The mice were killed at Day 29 after injection of the radiolabeled MoAb. The tumors and the organs were dissected and weighed. The remaining activity was measured in a gamma well counter. One part of the tumor was immediately fixed in Bouin's solution for autoradiography and the other in formaldehyde for microscopy. RESULTS: The study demonstrated significant radioimmunolocalization of the MoAb E4 into the DU-145 prostate tumor tissue in the animal model, with an average radiation dose of 0.08 Gy/MBq in the tumor. TS1 localized preferentially in necrotic parts of the tumor, yielding a tumor dose of 0.02 Gy/MBq. CONCLUSIONS: The MoAb E4 is a promising radiotracer for prostate cancer and may be used in radioimmunotherapy. As in earlier studies, TS1 shows significant radioimmunolocalization into necrotic tumor tissue, which also exists in prostate cancer.

Animals↗

PubMed1996

Impact of gastrointestinal dysfunction on survival after liver transplantation for familial amyloidotic polyneuropathy.

Liver transplantation is the only effective treatment of familial amyloidotic polyneuropathy type I (FAP). The aim of the present investigation was to identify factors at the time of submission for transplantation that had impact on survival, with special reference to gastrointestinal disturbances. All 28 liver-transplanted FAP patients evaluated at Umeå University Hospital were included in the study. A modified body mass index was used to assess nutritional status. Intestinal examinations were performed to diagnose bile acid malabsorption, gastric retention, and bacterial contamination of the small bowel. A significantly improved survival rate was found for patients in a good nutritional state (P = 0.002). Peripheral neurological symptoms were unrelated to survival, whereas increased mortality was found for patients with bile acid malabsorption (P < 0.05). Bacterial contamination and gastric retention were common complications of the disease. In conclusion, malabsorption and malnutrition have a profound impact on the outcome of liver transplantation for familial amyloidotic polyneuropathy.

Adult↗

PubMed1977

Leakage from T tube tracts as determined by contrast radiology.

The continuity of the T tube tract on removal of the drain was studied by fluoroscopic examination in 51 patients. Leakage was found in 25 cases (abdominal cavity 7, wound drain 6, local cavity 11, combined abdominal and wound drain leakage 1). No correlation was found between the incidence of pyrexia or pain and the presence of leakage. These complications, noted in 10 patients, are probably explained by bacterial contamination of the bile in combination with the trauma caused by extraction of the tube.

Adult↗

PubMed1976

Experimental evaluation of tube potential and contrast medium concentration for cholangiography.

Model cholangiographic experiments were performed in which the relationship between contrast medium concentration, duct diameter, calculus size and tube potential was analysed. The same degree of diagnostic reliability was obtained by increasing the tube potential as by diluting the contrast medium. A tube potential of 100 to 110 kV and a contrast medium concentration of 45 per cent were found to give the best result if the background density of the film was held constant.

Bile Ducts↗