44 resultados para Multivariate normal distribution


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PURPOSE: Successful photodynamic therapy of epithelial cancer requires a specific photosensitization of malignant tissue. We evaluate the intensity and localization of protoporphyrin IX (PpIX) in superficial transitional cell carcinoma and nonmalignant cells of the human bladder following topical administration of its precursor, either aminolevulinic acid (ALA) or hexylester aminolevulinate (HAL). MATERIALS AND METHODS: Solutions of ALA or HAL were instilled into the bladder of 18 patients presenting with recurrent transitional cell carcinoma. The distribution of PpIX through the bladder wall was studied on frozen biopsies using fluorescence microscopy and correlated with pathological findings. RESULTS: Topical bladder instillation with 180 mmol (3%) ALA administered for 6 hours or 8 mmol (0.2%) HAL administered for 4 hours gave similar results regarding intensity and tissue distribution of PpIX fluorescence, whereas 8 mmol HAL administered for 2 hours followed by 2 hours of resting time (2+2 hours concept) induced a PpIX fluorescence twice as high. The fluorescence remained limited to cancer cells. Only a trace of PpIX fluorescence was observed in suburothelial connective tissue, that is chorion, but none in the bladder smooth muscle regardless of experiment conditions. CONCLUSIONS: HAL is an excellent precursor for PpIX synthesis in bladder cancer. With the 2+2 hour topical administration condition it yielded the highest PpIX fluorescence intensity and fluorescence contrast between normal and malignant urothelial cells. This approach allows us to optimize PpIX tissue distribution for photodynamic therapy in superficial bladder cancer.

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BACKGROUND: Isolated lung perfusion (ILP) with free and a novel liposomal-encapsulated doxorubicin (Liporubicin, CT Sciences SA, Lausanne, Switzerland) was compared with respect to drug uptake and distribution in rat lungs bearing a sarcomatous tumor. METHODS: A single sarcomatous tumor was generated in the left lung of 39 Fischer rats, followed 10 days later by left-sided ILP (n = 36) with free and equimolar-dosed liposomal doxorubicin at doses of 100 microg (n = 9) and 400 microg (n = 9) for each doxorubicin formulation. In each perfused lung, the drug concentration and distribution were assessed in the tumor and in three areas of normal lung parenchyma by high-performance liquid chromatography (n = 6) and fluorescence microscopy (n = 3). Histologic assessment and immunostaining with von Willebrand factor was performed in 3 animals with untreated tumors. RESULTS: The sarcomatous tumors in controls were well vascularized with fine branching capillaries present throughout the tumors. Isolated lung perfusion resulted in a heterogeneous drug distribution within the perfused lung and a consistently lower drug uptake in tumors than in lung parenchyma for both doxorubicin formulations and both drug doses applied. Isolated lung perfusion with free doxorubicin resulted in a significantly higher drug uptake than Liporubicin in both the tumor and lung tissue for both drug doses applied (p < 0.01). However, the tumor/normal tissue drug ratio was lower for free than for liposomal doxorubicin at a drug dose of 100 microg (0.27 +/- 0.1 vs 0.53 +/- 0.5; p = 0.225) and similar for both doxorubicin formulations at a drug dose of 400 microg (0.67 +/- 0.2 vs 0.54 +/- 0.2; p = 0.335). Both doxorubicin formulations resulted in fluorescence signaling emerging from all tissue compartments of normal lung parenchyma but only in weak and sporadic signaling from the tumors confined to the tumor periphery and vessels situated within the tumor for both drug doses assessed. CONCLUSIONS: Isolated lung perfusion with free and liposomal doxorubicin resulted in a heterogeneous drug distribution within the perfused lung and in a lower drug uptake in tumors than in lung tissue for both doxorubicin formulations and drug doses applied.

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OBJECTIVE: To determine subregions of normal and abnormal cartilage in advanced stages of femorotibial osteoarthritis (OA) by mapping the entire femorotibial joint in a cohort of pre-total knee replacement (TKR) OA knees. DESIGN: We defined an areal subdivision of the femorotibial articular cartilage surface on CT arthrography (CTA), allowing the division of the femorotibial articular surface into multiple (up to n = 204 per knee) subregions and the comparison of the same areas between different knees. Two readers independently classified each cartilage area as normal, abnormal or non-assessable in 41 consecutive pre-TKR OA knees. RESULTS: A total of 6447 cartilage areas (from 41 knees) were considered assessable by both readers. The average proportion of preserved cartilage was lower in the medial femorotibial joint than in the lateral femorotibial joint for both readers (32.0/69.8% and 33.9/68.5% (medial/lateral) for reader 1 and 2 respectively, all P < 0.001). High frequencies of normal cartilage were observed at the posterior aspect of the medial condyle (up to 89%), and the anterior aspect of the lateral femorotibial compartment (up to 100%). The posterior aspect of the medial condyle was the area that most frequently exhibited preserved cartilage in the medial femorotibial joint, contrasting with the high frequency of cartilage lesions in the rest of that compartment. CONCLUSIONS: Cartilage at the posterior aspect of the medial condyle, and at the anterior aspect of the lateral femorotibial compartment, may be frequently preserved in advanced grades of OA.

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Objective: The management of sarcoma metastasis by systemic chemotherapy is often unsatisfactory. This has paradoxally been attributed to the leakiness of tumor neovessels which induce high intratumor interstitial fluid pressure (IFP) and limit convection forces that are important for drug distribution. In a rodent model, we have recently shown that photodynamic (PDT) pre treatment of lung metastasis could enhance their uptake of chemotherapy. We hypothesized that PDT transiently decreases tumor IFP which enhances convection and promotes drug distribution.Methods: Sarcoma tumors were generated sub-pleurally in the lungs of 12 rats. Animals were randomized at 10 days into i. no pre-treatment (control) and ii. low dose PDT pre-treatment (0・0625 mg/kg Visudyne, 10J/cm2 and 35 mW/cm2) followed by intravenous Liposomal doxorubicin (LiporubicinTM) administration. Using the wick-in-needle technique, we determined tumor and normal tissue IFP before, during and after PDT. In parallel, the uptake of LiporubicinTM was determined by high performance liquid chromatography in tumor and lung tissues.Results: Tumor IFP was significantly higher than normal tissue IFP in all animals. PDT pre-treatment did not affect normal tissue IFP but caused a significant decrease in tumor IFP (mean decrease by 2+/− 1mmHg) which lasted an average of 30 minutes before reaching baseline values. Tumor but not normal lung tissue LiporubicinTM uptake was significantly increased by 67% with PDT pre-treatment when liporubicin was allowed to circulate for one hour.Conclusion: Photodynamic therapy pre-treatment enhances LiporubicinTM uptake in sarcoma lung metastasis by transiently decreasing tumor IFP. These PDT conditions seem to specifically modulate tumor neovessels but not normal lung vessels.

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BACKGROUND: Intraabdominal adipose tissue (IAAT) is the body fat depot most strongly related to disease risk. Weight reduction is advocated for overweight people to reduce total body fat and IAAT, although little is known about the effect of weight loss on abdominal fat distribution in different races. OBJECTIVE: We compared the effects of diet-induced weight loss on changes in abdominal fat distribution in white and black women. DESIGN: We studied 23 white and 23 black women, similar in age and body composition, in the overweight state [mean body mass index (BMI; in kg/m(2)): 28.8] and the normal-weight state (mean BMI: 24.0) and 38 never-overweight control women (mean BMI: 23.4). We measured total body fat by using a 4-compartment model, trunk fat by using dual-energy X-ray absorptiometry, and cross-sectional areas of IAAT (at the fourth and fifth lumbar vertebrae) and subcutaneous abdominal adipose tissue (SAAT) by using computed tomography. RESULTS: Weight loss was similar in white and black women (13.1 and 12.6 kg, respectively), as were losses of total fat, trunk fat, and waist circumference. However, white women lost more IAAT (P < 0.001) and less SAAT (P < 0.03) than did black women. Fat patterns regressed toward those of their respective control groups. Changes in waist circumference correlated with changes in IAAT in white women (r = 0.54, P < 0.05) but not in black women (r = 0.19, NS). CONCLUSIONS: Despite comparable decreases in total and trunk fat, white women lost more IAAT and less SAAT than did black women. Waist circumference was not a suitable surrogate marker for tracking changes in the visceral fat compartment in black women.

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During the selection of monoclonal antibodies (MAb) raised against purified carcinoembryonic antigen (CEA), two MAbs were identified which immunoprecipitated a glycoprotein of 95 kD present both in perchloric acid extracts of normal lung and on the surface of normal granulocytes. This antigen was distinct from the previously reported normal glycoprotein crossreacting with CEA (NCA) which had a molecular weight of 55 kD. The difference between the smaller and the larger crossreacting antigens termed NCA-55 and NCA-95, respectively, was demonstrated by SDS-polyacrylamide gel electrophoresis, by elution from Sephadex-G200 and by selective binding to a series of anti-CEA MAb. Out of six MAb which all bound CEA purified from colon carcinoma, three did not react with these two crossreacting antigens, one bound only NCA-95, one reacted only with NCA-55 and one reacted with both NCA-55 and NCA-95. Immunoadsorbent purified preparations of 125I labelled NCA-95 and NCA-55 were found useful for the screening of new anti-CEA MAb. In addition, when tested on frozen sections of colon carcinoma, normal spleen, normal lung and pancreas, each type of MAb gave a clearly different pattern of reactivity. The three anti-CEA MAb which did not bind any of the crossreacting antigens stained only the colon carcinoma cells; the MAb binding to either one of the two types of NCA gave a similar pattern of reactivity both on colon carcinoma cells and on granulocytes. However, on normal lung and pancreas, the MAb binding NCA-55 stained granulocytes as well as bronchiolar and alveolar epithelial cells in lung and inter- and intra-lobular duct epithelial cells in pancreas, whereas the MAb binding only NCA-95 stained only the granulocytes. Thus, the newly identified NCA-95 appears to differ from NCA-55 not only in terms of molecular size and antigenicity but also by the fact that in normal lung and pancreas it is found in granulocytes but not in epithelial cells.

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GLUT2-null mice are hyperglycemic, hypoinsulinemic, hyperglucagonemic, and glycosuric and die within the first 3 weeks of life. Their endocrine pancreas shows a loss of first phase glucose-stimulated insulin secretion (GSIS) and inverse alpha to beta cell ratio. Here we show that reexpression by transgenesis of either GLUT1 or GLUT2 in the pancreatic beta cells of these mice allowed mouse survival and breeding. The rescued mice had normal-fed glycemia but fasted hypoglycemia, glycosuria, and an elevated glucagon to insulin ratio. Glucose tolerance was, however, normal. In vivo, insulin secretion assessed following hyperglycemic clamps was normal. In vitro, islet perifusion studies revealed that first phase of insulin secretion was restored as well by GLUT1 or GLUT2, and this was accompanied by normalization of the glucose utilization rate. The ratio of pancreatic insulin to glucagon and volume densities of alpha to beta cells were, however, not corrected. These data demonstrate that 1) reexpression of GLUT1 or GLUT2 in beta cells is sufficient to rescue GLUT2-null mice from lethality, 2) GLUT1 as well as GLUT2 can restore normal GSIS, 3) restoration of GSIS does not correct the abnormal composition of the endocrine pancreas. Thus, normal GSIS does not depend on transporter affinity but on the rate of uptake at stimulatory glucose concentrations.

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INTRODUCTION: Calcium-containing (CaC) crystals, including basic calcium phosphate (BCP) and calcium pyrophosphate dihydrate (CPP), are associated with destructive forms of osteoarthritis (OA). We assessed their distribution and biochemical and morphologic features in human knee OA cartilage. METHODS: We prospectively included 20 patients who underwent total knee replacement (TKR) for primary OA. CaC crystal characterization and identification involved Fourier-transform infra-red spectrometry and scanning electron microscopy of 8 to 10 cartilage zones of each knee, including medial and lateral femoral condyles and tibial plateaux and the intercondyle zone. Differential expression of genes involved in the mineralization process between cartilage with and without calcification was assessed in samples from 8 different patients by RT-PCR. Immunohistochemistry and histology studies were performed in 6 different patients. RESULTS: Mean (SEM) age and body mass index of patients at the time of TKR was 74.6 (1.7) years and 28.1 (1.6) kg/m², respectively. Preoperative X-rays showed joint calcifications (chondrocalcinosis) in 4 cases only. The medial femoro-tibial compartment was the most severely affected in all cases, and mean (SEM) Kellgren-Lawrence score was 3.8 (0.1). All 20 OA cartilages showed CaC crystals. The mineral content represented 7.7% (8.1%) of the cartilage weight. All patients showed BCP crystals, which were associated with CPP crystals for 8 joints. CaC crystals were present in all knee joint compartments and in a mean of 4.6 (1.7) of the 8 studied areas. Crystal content was similar between superficial and deep layers and between medial and femoral compartments. BCP samples showed spherical structures, typical of biological apatite, and CPP samples showed rod-shaped or cubic structures. The expression of several genes involved in mineralization, including human homolog of progressive ankylosis, plasma-cell-membrane glycoprotein 1 and tissue-nonspecific alkaline phosphatase, was upregulated in OA chondrocytes isolated from CaC crystal-containing cartilages. CONCLUSIONS: CaC crystal deposition is a widespread phenomenon in human OA articular cartilage involving the entire knee cartilage including macroscopically normal and less weight-bearing zones. Cartilage calcification is associated with altered expression of genes involved in the mineralisation process.

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BACKGROUND AND AIMS: Normal weight obesity (NWO) has been defined as an excessive body fat (BF) associated with a normal body mass index (BMI). Still, little is known regarding the effect of differing cut-offs for %BF on the prevalence of NWO. We thus conducted a study to assess the effect of modifying the cut-offs for excessive %BF on the prevalence of NWO. METHODS: We examined a convenience sample of 1523 Portuguese adults. BF was measured by validated hand-held bioimpedance. NWO was defined as a BMI < 25 kg/m2 and a %BF >30% or according to sex- and age-specific %BF cut-offs. RESULTS: Prevalence of NWO was 10.1% in women and 3.2% in men. In women, prevalence of NWO increased considerably with age, and virtually all women aged over 55 with a BMI < 25 kg/m2 were actually considered as NWO. Using sex-specific cut-offs for BF (men: 29.1%; women: 37.2%) led to moderately lower prevalence of NWO in women. Using sex and age-specific cut-offs for %BF considerably decreased the prevalence of NWO in women, i.e. 0.5e2.5% (depending on the criterion) but not in men, i.e. 1.9e3.4%. CONCLUSIONS: In women, the prevalence of NWO varies considerably according to the cut-off used to define excess BF, whereas a much smaller variation is found in men. While further studies are needed to describe the risk associated with NWO using various %BF cut-offs, this study suggests that sex- and age-specific cut-offs may be preferred.

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The distribution of immunoreactivity for the neurofilament triplet class of intermediate filament proteins was examined in the hippocampus of young, adult and elderly control cases and compared to that of Alzheimer's disease cases. In a similar fashion to non-human mammalian species, pyramidal neurons in the CA1 region showed a very low degree of neurofilament triplet immunoreactivity in the three younger control cases examined. However, in the other control cases of 49 years of age and older, many CA1 pyramidal neurons showed elevated neurofilament immunoreactivity. In the Alzheimer's disease cases, most of the surviving CA1 neurons showed intense labeling for the neurofilament triplet proteins, with many of these neurons giving off abnormal "sprouting" processes. Double labeling demonstrated that many of these neurons contained tangle-like or granular material that was immunoreactive for abnormal forms of tau and stained with thioflavine S, indicating that these neurons are in a transitional degenerative stage. An antibody to phosphorylated neurofilament proteins labeled a subset of neurofibrillary tangles in the Alzheimer's disease cases. However, following formic acid pre-treatment, the number of neurofibrillary tangles showing phosphorylated neurofilament protein immunoreactivity increased, with double labeling confirming that all of the tau-immunoreactive neurofibrillary tangles were also immunoreactive for phosphorylated neurofilament proteins. Immunoblotting demonstrated that there was a proportionately greater amount of the neurofilament triplet subunit proteins in hippocampal tissue from Alzheimer's disease cases as compared to controls. These results indicate that there are changes in the cytoskeleton of CA1 neurons associated with age which are likely to involve an increase in the level of neurofilament proteins and may be a predisposing factor contributing towards their high degree of vulnerability in degenerative conditions such as Alzheimer's disease. The cellular factors affecting hippocampal neurons during aging may be potentiated in Alzheimer's disease to result in even higher levels of intracellular neurofilament proteins and the progressive alterations of neurofilaments and other cytoskeletal proteins that finally results in neurofibrillary tangle formation and cellular degeneration.

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We propose robust estimators of the generalized log-gamma distribution and, more generally, of location-shape-scale families of distributions. A (weighted) Q tau estimator minimizes a tau scale of the differences between empirical and theoretical quantiles. It is n(1/2) consistent; unfortunately, it is not asymptotically normal and, therefore, inconvenient for inference. However, it is a convenient starting point for a one-step weighted likelihood estimator, where the weights are based on a disparity measure between the model density and a kernel density estimate. The one-step weighted likelihood estimator is asymptotically normal and fully efficient under the model. It is also highly robust under outlier contamination. Supplementary materials are available online.

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BACKGROUND: The pre-conditioning of tumor vessels by low-dose photodynamic therapy (L-PDT) was shown to enhance the distribution of chemotherapy in different tumor types. However, how light dose affects drug distribution and tumor response is unknown. Here we determined the effect of L-PDT fluence on vascular transport in human mesothelioma xenografts. The best L-PDT conditions regarding drug transport were then combined with Lipoplatin(®) to determine tumor response. in vivo. Lasers Surg. Med. 47:323-330, 2015. © 2015 Wiley Periodicals, Inc. METHODS: Nude mice bearing dorsal skinfold chambers were implanted with H-Meso1 cells. Tumors were treated by Visudyne(®) -mediated photodynamic therapy with 100 mW/cm(2) fluence rate and a variable fluence (5, 10, 30, and 50 J/cm(2) ). FITC-Dextran (FITC-D) distribution was assessed in real time in tumor and normal tissues. Tumor response was then determined with best L-PDT conditions combined to Lipoplatin(®) and compared to controls in luciferase expressing H-Meso1 tumors by size and whole body bioluminescence assessment (n = 7/group). RESULTS: Tumor uptake of FITC-D following L-PDT was significantly enhanced by 10-fold in the 10 J/cm(2) but not in the 5, 30, and 50 J/cm(2) groups compared to controls. Normal surrounding tissue uptake of FITC-D following L-PDT was significantly enhanced in the 30 J/cm(2) and 50 J/cm(2) groups compared to controls. Altogether, the FITC-D tumor to normal tissue ratio was significantly higher in the 10 J/cm(2) group compared others. Tumor growth was significantly delayed in animals treated by 10 J/cm2-L-PDT combined to Lipoplatin(®) compared to controls. CONCLUSIONS: Fluence of L-PDT is critical for the optimal distribution and effect of subsequently administered chemotherapy. These findings have an importance for the clinical translation of the vascular L-PDT concept in the clinics. Lasers Surg. Med. 47:323-330, 2015.

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Studies on niche evolution allow us to establish how species niches have changed over time as well as to identify how long-term evolutionary processes have led to present-day species distributions. Here, we investigate the patterns of climatic niche evolution in Tynanthus (Bignonieae, Bignoniaceae), a genus comprising narrowly distributed species. We test the hypothesis that niche conservatism has played an important role in the diversification history of this group of Neotropical lianas. For that, we perform univariate and multivariate comparisons between species' climatic niches and associated environmental data with information on species' phylogenetic relationships. We encountered considerable divergence in niches among species, indicating that niche conservatism in climatic variables has does not seem to havenot played a key role in the diversification of the genus. Our results are used as a basis to discuss patterns of ecological niche evolution in the group and to suggest novel approaches for future analyses.

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BACKGROUND: Many species contain evolutionarily distinct groups that are genetically highly differentiated but morphologically difficult to distinguish (i.e., cryptic species). The presence of cryptic species poses significant challenges for the accurate assessment of biodiversity and, if unrecognized, may lead to erroneous inferences in many fields of biological research and conservation. RESULTS: We tested for cryptic genetic variation within the broadly distributed alpine mayfly Baetis alpinus across several major European drainages in the central Alps. Bayesian clustering and multivariate analyses of nuclear microsatellite loci, combined with phylogenetic analyses of mitochondrial DNA, were used to assess population genetic structure and diversity. We identified two genetically highly differentiated lineages (A and B) that had no obvious differences in regional distribution patterns, and occurred in local sympatry. Furthermore, the two lineages differed in relative abundance, overall levels of genetic diversity as well as patterns of population structure: lineage A was abundant, widely distributed and had a higher level of genetic variation, whereas lineage B was less abundant, more prevalent in spring-fed tributaries than glacier-fed streams and restricted to high elevations. Subsequent morphological analyses revealed that traits previously acknowledged as intraspecific variation of B. alpinus in fact segregated these two lineages. CONCLUSIONS: Taken together, our findings indicate that even common and apparently ecologically well-studied species may consist of reproductively isolated units, with distinct evolutionary histories and likely different ecology and evolutionary potential. These findings emphasize the need to investigate hidden diversity even in well-known species to allow for appropriate assessment of biological diversity and conservation measures.