1000 resultados para Photodynamic action


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The renal site of the natriuretic effect of human, atrial natriuretic peptide (hANP) was studied using clearance techniques in eight salt-loaded normal volunteers undergoing maximal water diuresis. Lithium was used as a marker of proximal sodium reabsorption. According to a two-way, single blind, crossover design, hANP (Met12-(3-28)-eicosahexapeptide, (2 micrograms/min) or its vehicle (Ve) were infused for two hours, followed by a two-hour recovery period. Blood pressure, heart rate and insulin clearance remained unchanged. During hANP infusion, the filtration fraction increased slightly from 19.6 to 24.3% (P less than 0.001), fractional water excretion rose transiently at the beginning of the infusion. Fractional excretion of sodium increased markedly from 2.2% to 7.4% (P less than 0.001) but remained unchanged with Ve. ANP increased fractional excretion of lithium slightly from 46 to 58% (P less than 0.01), while it remained stable at 47% during Ve. The distal tubular rejection fraction of sodium calculated from sodium and lithium clearances rose markedly from 4.7 to 13% (P less than 0.001) and returned to 6.2% at the end of the recovery period. Thus, under salt loading and water diuresis conditions, hANP infusion did not alter GFR, but reduced proximal reabsorption of sodium, and markedly enhanced the fraction of sodium escaping distal tubular reabsorption, suggesting that hANP-induced natriuresis is due, for an important part, to inhibition of sodium reabsorption in the distal nephron.

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B lymphocytes are among the first cells to be infected by mouse mammary tumor virus (MMTV), and they play a crucial role in its life cycle. To study transcriptional regulation of MMTV in B cells, we have analyzed two areas of the long terminal repeat (LTR) next to the glucocorticoid receptor binding site, fp1 (at position -139 to -146 from the cap site) and fp2 (at -157 to -164). Both showed B-cell-specific protection in DNase I in vitro footprinting assays and contain binding sites for Ets transcription factors, a large family of proteins involved in cell proliferation and differentiation and oncogenic transformation. In gel retardation assays, fp1 and fp2 bound the heterodimeric Ets factor GA-binding protein (GABP) present in B-cell nuclear extracts, which was identified by various criteria: formation of dimers and tetramers, sensitivity to pro-oxidant conditions, inhibition of binding by specific antisera, and comigration of complexes with those formed by recombinant GABP. Mutations which prevented complex formation in vitro abolished glucocorticoid-stimulated transcription from an MMTV LTR linked to a reporter gene in transiently transfected B-cell lines, whereas they did not affect the basal level. Exogenously expressed GABP resulted in an increased level of hormone response of the LTR reporter plasmid and produced a synergistic effect with the coexpressed glucocorticoid receptor, indicating cooperation between the two. This is the first example of GABP cooperation with a steroid receptor, providing the opportunity for studying the integration of their intracellular signaling pathways.

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P>Aim: To determine the effects of imperfect adherence (i.e. occasionally missing prescribed doses), and the influence of rate of loss of antihypertensive effect during treatment interruption, on the predicted clinical effectiveness of antihypertensive drugs in reducing mean systolic blood pressure (SBP) and cardiovascular disease (CVD) risk.Method:The effects of imperfect adherence to antihypertensive treatment regimens were estimated using published patterns of missed doses, and taking into account the rate of loss of antihypertensive effect when doses are missed (loss of BP reduction in mmHg/day; the off-rate), which varies between drugs. Outcome measures were the predicted mean SBP reduction and CVD risk, determined from the Framingham Risk Equation for CVD.Results:In patients taking 75% of prescribed doses (typical of clinical practice), only long-acting drugs with an off-rate of similar to 1 mmHg/day were predicted to maintain almost the full mean SBP-lowering effect throughout the modelled period. In such patients, using shorter-acting drugs (e.g. an off-rate of similar to 5-6 mmHg/day) was predicted to lead to a clinically relevant loss of mean SBP reduction of > 2 mmHg. This change also influenced the predicted CVD risk reduction; in patients with a baseline 10-year CVD risk of 27.0% and who were taking 75% of prescribed doses, a difference in off-rate from 1 to 5 mmHg/day led to a predicted 0.5% absolute increase in 10-year CVD risk.Conclusions:In patients who occasionally miss doses of antihypertensives, modest differences in the rate of loss of antihypertensive effect following treatment interruption may have a clinically relevant impact on SBP reduction and CVD risk. While clinicians must make every effort to counsel and encourage each of their patients to adhere to their prescribed medication, it may also be prudent to prescribe drugs with a low off-rate to mitigate the potential consequences of missing doses.

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Lymphatic vessels transport fluid, antigens, and immune cells to the lymph nodes to orchestrate adaptive immunity and maintain peripheral tolerance. Lymphangiogenesis has been associated with inflammation, cancer metastasis, autoimmunity, tolerance and transplant rejection, and thus, targeted lymphatic ablation is a potential therapeutic strategy for treating or preventing such events. Here we define conditions that lead to specific and local closure of the lymphatic vasculature using photodynamic therapy (PDT). Lymphatic-specific PDT was performed by irradiation of the photosensitizer verteporfin that effectively accumulates within collecting lymphatic vessels after local intradermal injection. We found that anti-lymphatic PDT induced necrosis of endothelial cells and pericytes, which preceded the functional occlusion of lymphatic collectors. This was specific to lymphatic vessels at low verteporfin dose, while higher doses also affected local blood vessels. In contrast, light dose (fluence) did not affect blood vessel perfusion, but did affect regeneration time of occluded lymphatic vessels. Lymphatic vessels eventually regenerated by recanalization of blocked collectors, with a characteristic hyperplasia of peri-lymphatic smooth muscle cells. The restoration of lymphatic function occurred with minimal remodeling of non-lymphatic tissue. Thus, anti-lymphatic PDT allows control of lymphatic ablation and regeneration by alteration of light fluence and photosensitizer dose.

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Ocular neovascularizations are responsible for irreversible loss of vision in various diseases, including age-related macular degeneration. Treatments have changed greatly, and photodynamic therapy with verteporfin has come into common use. However, the visual prognosis remains poor. The recent approval of new antiangiogenic molecules such as ranibizumab and pegaptanib should allow for new therapeutical possibilities. The unapproved ophthalmological use of bevacizumab requires further studies. This paper updates what is known about old and new neovascularization treatments: their mechanism of action, their efficacy, and their toxicity. It reviews the principal clinical studies, and concludes with the recognized recommendations. For the first time, ophthalmologists can hope not only to stabilize loss of vision, but also to improve visual acuity. Complementary treatments can now be tested in associations, concomitantly or not, with the hope of improving visual results.

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Agency performancce plan and action plan for the Iowa Civil Rights Commission

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The objectives of the project were to develop methodologies for (i) prediction and measurement of the magnitude of pressure which develops within pores of saturated porous materials upon freezing, (ii) determination of pore structure (pore size distribution) of porous materials; (iii) prediction and measurement of the rate with which pore ice grows; and (iv) prediction of frost susceptibility of porous materials with varying pore structures. As with all research endeavors solution of one problem leads to another one and this project was no exception. Emergence of new problems and the measures taken as the work progressed were discussed in progress reports submitted to the board. This final report will discuss only the conclusive finds and suggest measures to be taken for future investigations. The theory discussed in the proposal is not repeated in this report for the sake of brevity. However, the paper published as part of this project containing the theory is attached as Appendix I for the reader interested in the theory. In conformity with the objectives, this report consists of four parts. In accordance with the project contract two ice porosimeters were built and one will be delivered to the Iowa DOT after training of a DOT technician under the supervision of Mr. Wendell Dubberke with assistance from ISU researchers. During the training period debugging and further improvements in software will continue.

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BACKGROUND AND OBJECTIVES: Experimental assessment of photodynamic therapy (PDT) for malignant pleural mesothelioma using a polyethylene glycol conjugate of meta-tetrahydroxyphenylchlorin (PEG-mTHPC). STUDY DESIGN/MATERIALS AND METHODS: (a) PDT was tested on H-meso-1 xenografts (652 nm laser light; fluence 10 J/cm(2); 0.93, 9.3, or 27.8 mg/kg of PEG-mTHPC; drug-light intervals 3-8 days). (b) Intraoperative PDT with similar treatment conditions was performed in the chest cavity of minipigs (n = 18) following extrapleural pneumonectomy (EPP) using an optical integrating balloon device combined with in situ light dosimetry. RESULTS: (a) PDT using PEG-mTHPC resulted in larger extent of tumor necrosis than in untreated tumors (P < or = 0.01) without causing damage to normal tissue. (b) Intraoperative PDT following EPP was well tolerated in 17 of 18 animals. Mean fluence and fluence rates measured at four sites of the chest cavity ranged from 10.2 +/- 0.2 to 13.2 +/- 2.3 J/cm(2) and 5.5 +/- 1.2 to 7.9 +/- 1.7 mW/cm(2) (mean +/- SD). Histology 3 months after light delivery revealed no PDT related tissue injury in all but one animal. CONCLUSIONS: PEG-mTHPC mediated PDT showed selective destruction of mesothelioma xenografts without causing damage to intrathoracic organs in pigs at similar treatment conditions. The light delivery system afforded regular light distribution to different parts of the chest cavity.

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BACKGROUND: Studies on hexaminolevulinate (HAL) cystoscopy report improved detection of bladder tumours. However, recent meta-analyses report conflicting effects on recurrence. OBJECTIVE: To assess available clinical data for blue light (BL) HAL cystoscopy on the detection of Ta/T1 and carcinoma in situ (CIS) tumours, and on tumour recurrence. DESIGN, SETTING, AND PARTICIPANTS: This meta-analysis reviewed raw data from prospective studies on 1345 patients with known or suspected non-muscle-invasive bladder cancer (NMIBC). INTERVENTION: A single application of HAL cystoscopy was used as an adjunct to white light (WL) cystoscopy. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: We studied the detection of NMIBC (intention to treat [ITT]: n=831; six studies) and recurrence (per protocol: n=634; three studies) up to 1 yr. DerSimonian and Laird's random-effects model was used to obtain pooled relative risks (RRs) and associated 95% confidence intervals (CIs) for outcomes for detection. RESULTS AND LIMITATIONS: BL cystoscopy detected significantly more Ta tumours (14.7%; p<0.001; odds ratio [OR]: 4.898; 95% CI, 1.937-12.390) and CIS lesions (40.8%; p<0.001; OR: 12.372; 95% CI, 6.343-24.133) than WL. There were 24.9% patients with at least one additional Ta/T1 tumour seen with BL (p<0.001), significant also in patients with primary (20.7%; p<0.001) and recurrent cancer (27.7%; p<0.001), and in patients at high risk (27.0%; p<0.001) and intermediate risk (35.7%; p=0.004). In 26.7% of patients, CIS was detected only by BL (p<0.001) and was also significant in patients with primary (28.0%; p<0.001) and recurrent cancer (25.0%; p<0.001). Recurrence rates up to 12 mo were significantly lower overall with BL, 34.5% versus 45.4% (p=0.006; RR: 0.761 [0.627-0.924]), and lower in patients with T1 or CIS (p=0.052; RR: 0.696 [0.482-1.003]), Ta (p=0.040; RR: 0.804 [0.653-0.991]), and in high-risk (p=0.050) and low-risk (p=0.029) subgroups. Some subgroups had too few patients to allow statistically meaningful analysis. Heterogeneity was minimised by the statistical analysis method used. CONCLUSIONS: This meta-analysis confirms that HAL BL cystoscopy significantly improves the detection of bladder tumours leading to a reduction of recurrence at 9-12 mo. The benefit is independent of the level of risk and is evident in patients with Ta, T1, CIS, primary, and recurrent cancer.

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