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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
71

Vitamin D and its receptor in parathyroid tumors

Correa, Pamela January 2002 (has links)
Correa, P. 2002. Vitamin D and its receptor in parathyroid tumors. Acta Universitatis Upsaliensis. Comprehensive Summaries of Uppsala Dissertations from the Faculty of Medicine 1186. 49 pp. Uppsala. ISBN 91-554-541-0 Hyperparathyroidism (HPT) is characterized by tumor development in the parathyroid glands and excessive production of parathyroid hormone. Parathyroidectomy is the only considered therapy for the majority of patients. LOH (loss of heterozygosity) analysis revealed putative tumor suppressor genes on chromosome regions 1p and 11q in tumors from patients with truly mild hypercalcemia. Active vitamin D [1,25(OH)2D3] and its receptors, the vitamin D receptor (VDR), are essential regulators of the calcium homeostasis and are involved in HPT development. The VDR-FokI polymorphism, coupled to bone mineral density, was found not to be associated to development of primary HPT (pHPT). The total VDR mRNA levels is reduced in adenomas of pHPT as well as in hyperplastic glands of secondary HPT (sHPT). The VDR exon 1f transcripts were exclusively downregulated in the adenomas of pHPT, suggesting default regulation of the tissue-specially expressed VDR 1f promoter. The cytochrome P450 enzymes responsible for synthesis and degradation of 1,25(OH)2D3, namely vitamin D3 25-hydroxylase (25-hydroxylase), 25-hydroxyvitamin D3 1a-hydroxylase (1a-hydroxylase) and 25-hydroxyvitamin D3 24-hydroxylase (24-hydroxylase) were found to be expressed in normal and pathological parathyroid glands. Tumors of pHPT and sHPT demonstrated increased 1a-hydroxylase and reduced 24- and 25-hydroxylase expression, suggesting an augmented local production of active vitamin D. In contrast, parathyroid carcinomas displayed reduced expression of all three hydroxylases. The gained knowledge of vitamin D metabolism and catabolism in parathyroid tumors may indicate possibilities for novel treatment of sHPT and perhaps pHPT.
72

Angiogenesis in childhood malignancies

Sköldenberg, Erik January 2003 (has links)
Angiogenesis is necessary for the growth and spread of solid tumors. In these studies angiogenesis was measured in childhood malignancies in general and in Wilms’ tumor in particular, and cutting needle biopsy (CNB) specimens were evaluated for diagnosis in childhood renal tumors. In 33 patients with Wilms’ tumor, tumor capillaries were quantified, expression of angiogenic growth factors in tumor tissue investigated, and concentrations of angiogenic growth factors in serum measured. Reference values for angiogenic growth factors were obtained in 80 healthy adults (fibroblast growth factor 2 [FGF-2], vascular endothelial growth factor A [VEGF-A]) and 94 healthy children (angiogenin [ANG], epidermal growth factor [EGF], FGF-2, hepatocyte growth factor [HGF], tumor necrosis factor alpha [TNFA] and VEGF-A) aged 0.5-18 years. These reference values were compared with values in sera taken at diagnosis in 268 children with tumors and leukemias. CNB specimens were evaluated in 25 children with renal tumors. A large number of capillaries was an independent prognostic factor for a poor outcome in Wilms’ tumor. Angiogenic growth factors were expressed in Wilms’ tumor tissue, and elevated concentrations of HGF and VEGF-A were found in both benign and malignant tumors. HGF was increased in leukemia, and TNFA was increased in leukemia, lymphoma and neuroblastoma. CNB, which proved to be a safe procedure, had a sensitivity of 76%. These studies have demonstrated that quantification of capillaries is a prognostic factor in Wilms’ tumor and that HGF, TNFA and VEGF-A are frequently elevated in sera from children with cancer. Quantification of capillaries in tumor tissue and of circulating angiogenic growth factors would therefore seem to be of clinical relevance in managing children with cancer.
73

Modulation of the Immune Response in Concordant Xenotransplantation

Bersztel, Adam January 2003 (has links)
Xenotransplantation, i.e. transplantation between different species, could be a possible solution to the present shortage of organ donors. The immunological response to a xenograft is strong and difficult to suppress. It is driven both by the humoral and cellular part of the immune system. The aim of this thesis was to characterise and modulate this response in a concordant mouse-to-rat model, using both vascularised and non-vascularised grafts. Exposure of mouse cells or tissue to the circulation of a rat, either through transplantation or transfusions, easily evoked an immune response, consisting of IgM antibodies. A response that was aimed both at antigens present on mouse mononuclear cells and on erythrocytes. A non-immunosuppressed rat rejected a mouse heart graft within three days. The combined use of cyclosporine A (CyA) and deoxyspergualin (DSG) as immunosuppression prevented the rejection of vascularised heart transplants as well as of non-vascularised pancreatic islet grafts. This acceptance was sustained for the heart transplant also after the termination of DSG treatment, but not for the pancreatic islet graft. Furthermore, a second heart graft was accepted when transplanted under monotherapy with CyA 56-154 days after the first transplantation. This finding was interpreted as a humoral unresponsiveness, which could not be reproduced when the primary heart was substituted with a cellular graft, consisting of pancreatic islets or heart cells, or by blood transfusions. However, the rejection of a mouse heart after blood transfusions occurred in the absence of antibodies directed against mouse erythrocytes, in contrast to the observations in non-transfused animals. This indicates that a partial humoral tolerance restricted to the response against erythrocytes can be induced. This mechanism may offer a possibility to induce total humoral tolerance against a xenograft if the appropriate antigens are administered in conjunction with CyA and DSG.
74

Experimental Diagnostics and Therapeutics of Invasive Urinary Bladder Cancer

Sherif, Amir January 2003 (has links)
The two purposes of this thesis were to evaluate new diagnostic techniques of lymphnode staging in invasive bladder cancer and to evaluate the results of neoadjuvant chemotherapy in invasive bladder cancer. Sentinel node detection was performed in 13 patients in preparation for radical cystectomy. The method showed to be feasible, and the results displayed the occurrence of metastatic nodes outside the traditional area of diagnostic dissection in a majority of patients. Four patients were metastasized, each one with one metastatic node detected with the help of the sentinel node procedure. Four randomly selected sentinel nodes from four different unmetastasized patients were compared to the four metastatic sentinel nodes from the first series. After microdissection, p53 genomic structure, immunohistochemical expression and MVD (microvessel density) were assessed in the primary tumors and corresponding sentinel nodes. The results suggested that invasive bladder cancer mainly involved monoclonal proliferation with predominantly homogenous biomarker profile, but there were also signs of clonal evolution. The Nordic Cystectomy Trial 2 (NCT2), is a randomized prospective trial investigating the possible benefit of neoadjuvant chemotherapy versus cystectomy only, in 311 eligible patients with urinary bladder cancer T2-T4aNXM0.Evaluation of overall survival did not show any statistically significant benefit in the experimental arm. This probably due to lack of statistical power. To increase the statistical power we performed a combined analysis of randomized patients from both the Nordic Cystectomy Trial 1 (NCT1) and NCT2, n = 620. Eligible patients from NCT1 had T1G3, T2-T4a NXM0 urinary bladder cancer. Standard meta-analysis methods were used. The only end-point analysed was overall survival. Neoadjuvant platinum based combination therapy was associated with a 20 % reduction in the relative hazard in probability of death.
75

Intraperitoneal 5-Fluorouracil treatment of cancer - clinical and experimental studies

Öman, Mikael January 2004 (has links)
Background:Pancreas cancer is a most aggressive malignancy. More than 80% of patients diagnosed with pancreas cancer, exhibit such advanced disease, that curative surgery is impossible. Systemic chemotherapy prolongs survival to 5-9 months. High concentrations of chemotherapeutic agents in the abdominal cavity and in the lymphatics draining the area is achieved by intraperitoneal administration. Vasopressin decreases splanchnic blood flow, reducing the intraperitoneal uptake of drugs, thus raising the local and lymphatic dose intensity. Aim: The aim of the study was to investigate the feasibility and tumour response of intraperitoneal 5-Fluorouracil (5-FU) treatment in non-resectable pancreas cancer, using vasopressin to improve the pharmacokinetic profile. Further, to study the effect of vasopressin on peritoneal blood flow, altered by intraperitoneal 5-FU or the presence of peritoneal carcinomatosis. Methods: In the animal experiments, the 133Xe-clearance technique and as a comparison Laser doppler flow, were used to identify changes of peritoneal blood flow caused by vasopressin in unmanipulated animals and in animals with peritoneal carcinomatosis or animals given intraperitoneal 5-FU. In the clinical studies, 68 (39 women/29 men) patients, with a non-resectable ductal pancreas cancer and a Karnovsky Index ≥70 were included. Patients were treated with 750-1500 mg/m2 5-FU intraperitoneally through a Port-a-cath and Leucovorin 100 mg/m2 intravenously on two consecutive days every 21 days until progression. Seventeen patients, receiving 750 mg/m2 5-FU, were given concomitant vasopressin 0.1 IU/min during 180 minutes, alternatively day 1 or 2. Results: In the animal experiments, vasopressin 0.07 IU/kg/min significantly reduced the 133Xe-clearance. Intraperitoneal 5-FU decreased the basal peritoneal blood flow and abrogated the vasopressin effect for 1-2 days. The presence of peritoneal carcinomatosis did not influence the basal peritoneal blood flow, nor the reduction of peritoneal blood flow caused by vasopressin. In the clinical studies, the treatment with intraperitoneal 5-FU was well tolerated, with no WHO Grade 3 or 4 toxicity with doses up to 1250 mg/m2. Thirty patients achieved at least stable disease at three months. The median survival time was 8.0 (range 0.8-54.1) months. There was a significant reduction of 5-FU Cmax on day 2, but no significant reduction of AUC, when vasopressin was given. Conclusion: Peritoneal blood flow changes caused by vasopressin can be estimated with the 133Xe-clearance technique. Intraperitoneal 5-FU but not peritoneal carcinomatosis decreases the vasopressin induced 133Xe-clearance reduction, 1-2 days after administration. In patients with non-resectable pancreas cancer, intraperitoneal 5-FU up to 1250 mg/m2 for two days every third week can be given without WHO grade 3 and 4 toxicity. The treatment is well tolerated with few and minor side effects. Tumour responses were observed. Addition of vasopressin does not significantly enhance the pharmacokinetics of intraperitoneal 5-Flurorouracil, but adds toxicity.
76

Regulation of Fibroblast Activity by Keratinocytes / Keratinocyters påverkan på fibroblasters aktivitet

Nowinski, Daniel January 2005 (has links)
In the healing of cutaneous wounds, paracrine communication between keratinocytes and fibroblasts regulates cell differentiation, proliferation and synthesis of extracellular matrix. Deficient epidermal coverage, as seen in burn-wounds, frequently results in hypertrophic scars. Previous studies suggest that keratinocytes downregulate the production of collagen and profibrotic factors in fibroblasts. We hypothesized that keratinocytes downregulate the expression of the profibrotic factor connective tissue growth factor (CTGF) in fibroblasts, and regulate fibroblast expression of genes important to wound healing. In keratinocyte-fibroblast cocultures, keratinocytes downregulated CTGF mRNA and protein in fibroblasts, through the secretion of interleukin-1 (IL-1) α. Using Affymetrix DNA microarrays, it was demonstrated that factors from keratinocytes regulate the expression of 69 genes important to wound healing. The regulation of 16 of these genes was confirmed by Northern blotting, and IL-1α from keratinocytes regulated all the 16 genes examined. IL-1-mediated CTGF gene regulation was further investigated. Both IL-1 isoforms, α and β, suppressed CTGF expression through an inhibition of CTGF promoter activity. Interestingly, transforming growth factor-β-stimulated Smad phosphorylation was not affected by IL-1. Finally, we hypothesized that CTGF is downregulated in burn wound by split-thickness skin grafting and that the expression of CTGF is suppressed during reepithelialization. The expression of CTGF protein was decreased in successfully skin-grafted wound areas, and increased in open, granulating burn wounds. Moreover, CTGF protein expression was absent beneath the migrating edge of reepithelialization ex vivo. In conclusion, we demonstrate that, in in vitro models, keratinocyte-derived IL-1α regulates the expression of CTGF and other genes with importance to wound healing. Furthermore, it is shown that CTGF expression is suppressed by epidermal wound coverage i burn wounds. These findings may have implications for the understanding of keratinocyte-fibroblast interplay during wound healing and in hypertrophic scar pathogenesis.
77

Varicose Veins : Aspects on Diagnosis and Surgical Treatment

Blomgren, Lena January 2005 (has links)
Treatment for varicose veins (VV) is insufficiently evidence based and recurrence rates are high. The aim of this thesis was to study the long-term results after VV surgery, risk factors for recurrences and the effect of preoperative duplex scanning on recurrence rate, quality of life (QoL) and costs. In a follow-up study 89 patients with 100 legs operated on for VV 6–10 years earlier were re-examined with duplex, in 13 cases also with varicography. 57% had incompetent vessels in the groin visible with duplex, equally well defined by varicography. Residual branches could not be differentiated from new vessel formation. The recurrence rate did not correlate to the surgeon’s level of experience or perioperative difficulties at primary surgery. In a prospective randomized study 293 patients (343 legs) were operated on for primary VV with or without preoperative duplex. Duplex was done postoperatively, at 2 months and 2 years. QoL was measured with SF-36 preoperatively, at 1 month, 1 year and 2 years. After 2 years the number of reoperations were 2 in the group with preoperative duplex and 14 in the group without (p=0.002). Incompetent veins were seen in the saphenofemoral or saphenopopliteal junction in 19 and 53 legs respectively (p<0.001). Preoperative QoL was worse in the VV patients compared to a reference population, and was normalised 2 years postoperatively. The improved surgical result in the duplex group was not reflected in a significantly higher QoL. The lower costs for redo surgery in the duplex group did not offset the costs for duplex, partly due to more extensive primary surgery. A significant proportion of recurrences after 2 years was new vessel formation and progression of disease. Preoperative perforating vein incompetence did not influence recurrence rate, and was abolished without specific interruption in 60% at 2 years postoperatively.
78

Haemorrhoids : Aspects of Symptoms and Results after Surgery

Jóhannsson, Helgi Örn January 2005 (has links)
One hundred haemorrhoid patients were compared with 300 matched control persons. Haemorrhoid symptoms and bowel symptoms were studied. Most common symptom of the patients was bleeding (44%), followed by prolapse (24%), hygiene problem (14%), pain (12%) and itching (5%). Bowel symptoms, as bloating and evacuation difficulties, possibly related to IBS, were frequent among the patients. 556 patients were operated upon with Milligan-Morgan haemorrhoidectomy. 418 (81%) answered a questionnaire on results, and on disturbances in anal continence. Totally140 (33%) reported recurrence, and 139 (33%) patients reported anal incontinence. Forty of the 139 patients associated this to the surgical procedure. Female gender was associated to increased risk of incontinence. The 40 patients who reported incontinence, were invited to undergo ano-rectal manometry, saline infusion test, endo-anal ultrasound, proctoscopy and clinical examination. Altogether 19 patients approved to participate. Matched control subjects and 15 persons previously operated for haemorrhoids, but without symptoms of incontinence, served as two reference groups. Incontinence score and saline infusion test showed significantly poorer continence in the patient group. Endo-anal ultrasound showed injury to the external sphincter in 20% of the patients. Anal pressure was slightly lower in the patient group, but the difference was not significant. Totally 225 patients were randomised to Milligan-Morgan or Ferguson haemorrhoidectomy. Primary aim was to study changes in anal continence. Other aims were to study postoperative pain, wound healing, complications, patient satisfaction and recurrence and changes in bowel function. Patients in the Ferguson group reported, slightly quicker wound healing (P=0.06). Postoperative pain was equal, as was rate of complications. After one year the Ferguson group reported lower incontinence score, and more satisfied patients. Recurrence rate was equal, 15-17%. Most bowel symptoms were reduced one year after surgery. In conclusion, functional bowel symptoms are common in haemorrhoid patients. Haemorrhoidectomy is associated with risk for incontinence in 5-10% of patients and females are at greater risk. A proportion of the patients who claim postoperative incontinence have physiological signs of sphincter incompetence, and external sphincter injuries are observed in those patients. Ferguson haemorrhoidectomy results in better anal continence and more satisfied patients.
79

Dupuytren´s Contracture : Features and Consequences

Wilbrand, Stephan January 2002 (has links)
Dupuytren's contracture (DC) is a fibromatous disease of the palmar fascia of unknown etiology. The present study was undertaken in order to assess pathophysiological mechanisms and consequences. In a cohort study of 2,375 patients operated for DC at the Department of Hand Surgery, Uppsala there was a male: female ratio of 5.9:1. Women had a higher mean age at first operation than men. One-third of the men and one-quarter of the women required repeated surgery. Early age at first operation was associated with recurrent disease. The risk of cancer was determined in 15,212 patients operated on for DC in Sweden. The overall relative risk was increased by 24%. There was a significantly increased risk for buccal, oesophageal, gastric, lung and pancreatic cancers, which indicates that smoking and alcohol abuse are probable risk factors for DC. Furthermore, there was an increased frequency of fibrosarcoma and malignant fibrous histiocytoma, the cause of which is unexplained The causes of death were evaluated in a national cohort of 16,517 patients operated for DC. There was an overall increased mortality (SMR=1.06), inversely related to age and significant for both sexes, in patients under 70 years. The risk estimate was highest for endocrine-, gastrointestinal-, and respiratory diseases, and accidents. There was also an increased SMR for cardiovascular diseases in younger patients more than 10 years after surgery. The most probable mechanism is related to smoking and other lifestyle factors. Outcome after surgery was not related to the immunohistochemical expression of connective tissue activation markers, such as collagen type IV, integrin α5, laminin, smooth muscle α-actin, procollagen type I, and desmin, in surgical specimens in a prospectively investigated group of patients. Furthermore, there were no associations between gender, age at onset of DC, number of operations, heredity, diabetes mellitus, or medication for cardiovascular disease, and the expression of the different markers. The individual characteristics that place a person at high risk are, thus, not obviously related to ongoing connective tissue production at time of surgery or to connective tissue activity in its conventionally used sense.
80

Hepatic and Peritoneal Colorectal Metastases : Aspects of Prognosis and Treatment

Mahteme, Haile January 2001 (has links)
Although two-thirds of colorectal cancer patients are cured by surgery, approximately 50% of the patients with this disease develop locally recurrent or distant metastases during the course of their illness. The aim of this study was to identify metastatic sites associated with poor prognosis in rectal cancer and then to investigate methods that can prevent the development and growth of metastases and optimise uptake of drugs at these sites in animal models. In a defined population, 151 patients with irresectable metastatic or local rectal cancer were identified. Bilateral liver involvement, abnormal liver function tests, paritoneal growth or abdominal lymph node metastases implied a poor prognosis. In a study on Wistar rats with liver metastases from colorectal cancer, blocking of hyaluronan uptake and elimination by the liver enhanced the hyaluronan uptake in liver metastases. Hyaluronan may thus be used to promote uptake of drugs in specific hyaluronan receptor-positive turnout sites. Adjuvant intravenous radioimmunotherapy delivered as a specific or unspecific monoclonal antibody prevented human colonic cancer calls inoculated into the portal vein of nude rats from developing into liver metastases. Furthermore, intraperitoneally administered radioimmunotherapy inhibited the growth of peritoneal metastases. Blocking of 5-FU absorption with a vasoconstrictive agent enhanced the uptake of 5-FU in peritoneal metastases. In addition, the uptake of 5-FU in peritoneal metastases could be improved when these turnouts were mechanically disintegrated by surgical turnout reduction and the drug was given intraperitoneally.

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