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1.
J Environ Manage ; 351: 119787, 2024 Feb.
Article in English | MEDLINE | ID: mdl-38081085

ABSTRACT

Monitoring for adaptive management (AM) involves collection of data with the aim of reducing uncertainty about links between human pressures (e.g. water abstraction from rivers), consequent stressors (e.g. low river flows) and environmental state (e.g. biodiversity). 'Surveillance monitoring' involves documenting trends in state, without the aim of understanding relationships between state, stressors, and pressures. Critics have highlighted that surveillance monitoring dominates monitoring investments but is not supporting AM. Decision-makers continue to be disappointed by monitoring data that are unsuitable for AM, yet designers of monitoring programs tend to make decisions that reinforce rather than reimagine the status quo. We argue that a structured, collaborative approach to objective-setting is required to break the status quo. We collaborated with regional management authorities to develop monitoring objectives and implementation strategies to support AM of New Zealand's rivers. Our collaborative approach discouraged 'failure fearing' and encouraged reimagining 'what could be' as opposed to 'what is.' Seventeen monitoring objectives were identified based on the AM requirements of national policy and regional authorities. Several objectives-particularly those arising from national policy-stretch the limits of what environmental science can currently provide. There were also strong trade-offs among objectives. We offer practical implementation strategies for overcoming the technical challenges of, and reducing trade-offs among, monitoring objectives. These strategies point to a monitoring program that contrasts strongly with one aimed at surveillance. Monitoring for AM is more complex than monitoring for surveillance, so strong leadership is required for successful implementation.


Subject(s)
Ecosystem , Rivers , Humans , Environmental Monitoring , Biodiversity , Uncertainty
2.
NPJ Breast Cancer ; 8(1): 122, 2022 Nov 11.
Article in English | MEDLINE | ID: mdl-36369506

ABSTRACT

Circulating IL-6, an activator of JAK/STAT signaling, is associated with poor prognosis and aromatase inhibitor (AI) resistance in hormone-receptor positive (HR+) breast cancer. Here we report the results of a phase 2 single-arm Simon 2-stage trial combining Ruxolitinib, an oral selective inhibitor of JAK1/2, with exemestane, a steroidal AI, in patients with HR+ metastatic breast cancer (MBC) after progression on non-steroidal AI (NSAI). Safety and efficacy were primary objectives, and analysis of inflammatory markers as predictors of response was a key secondary objective. Twenty-five subjects enrolled. The combination of ruxolitinib and exemestane was safe, though anemia requiring transfusion in 5/15 (33%) at the 25 mg dose in stage 1 led to a reduction to 15 mg twice daily in stage 2 (with no additional transfusions). Clinical benefit rate (CBR) in the overall study population was 24% (95% CI 9.4-45.1); 6/25 patients demonstrated stable disease for ≥6 months. Median progression-free survival was 2.8 months (95% CI 2.6-3.9). Exploratory biomarkers revealed high levels of systemic inflammation and 60% harbored a high-risk IL-6 genotype. Pharmacodynamics demonstrated modest on-target inhibition of phosphorylated-STAT3 by ruxolitinib at a tolerable dose. Thus, ruxolitinib combined with exemestane at a tolerable dose was safe but minimally active in AI-resistant tumors of patients with high levels of systemic inflammation. These findings highlight the need for more potent and specific therapies targeting inflammation in MBC.

3.
Med Phys ; 47(6): 2380-2391, 2020 Jun.
Article in English | MEDLINE | ID: mdl-32160322

ABSTRACT

PURPOSE: Many methods are available to segment structural magnetic resonance (MR) images of the brain into different tissue types. These have generally been developed for research purposes but there is some clinical use in the diagnosis of neurodegenerative diseases such as dementia. The potential exists for computed tomography (CT) segmentation to be used in place of MRI segmentation, but this will require a method to verify the accuracy of CT processing, particularly if algorithms developed for MR are used, as MR has notably greater tissue contrast. METHODS: To investigate these issues we have created a three-dimensional (3D) printed brain with realistic Hounsfield unit (HU) values based on tissue maps segmented directly from an individual T1 MRI scan of a normal subject. Several T1 MRI scans of normal subjects from the ADNI database were segmented using SPM12 and used to create stereolithography files of different tissues for 3D printing. The attenuation properties of several material blends were investigated, and three suitable formulations were used to print an object expected to have realistic geometry and attenuation properties. A skull was simulated by coating the object with plaster of Paris impregnated bandages. Using two CT scanners, the realism of the phantom was assessed by the measurement of HU values, SPM12 segmentation and comparison with the source data used to create the phantom. RESULTS: Realistic relative HU values were measured although a subtraction of 60 was required to obtain equivalence with the expected values (gray matter 32.9-35.8 phantom, 29.9-34.2 literature). Segmentation of images acquired at different kVps/mAs showed excellent agreement with the source data (Dice Similarity Coefficient 0.79 for gray matter). The performance of two scanners with two segmentation methods was compared, with the scanners found to have similar performance and with one segmentation method clearly superior to the other. CONCLUSION: The ability to use 3D printing to create a realistic (in terms of geometry and attenuation properties) head phantom has been demonstrated and used in an initial assessment of CT segmentation accuracy using freely available software developed for MRI.


Subject(s)
Neuroimaging , Tomography, X-Ray Computed , Head/diagnostic imaging , Humans , Magnetic Resonance Imaging , Phantoms, Imaging
4.
Annu Int Conf IEEE Eng Med Biol Soc ; 2019: 454-457, 2019 Jul.
Article in English | MEDLINE | ID: mdl-31945936

ABSTRACT

Diagnosis of brain diseases is considered one of the most challenging medical tasks to perform, even for medical experts who rely on high-resolution anatomical images to identify signs of abnormalities by visual inspection. However, new computational tools which assist to automate this diagnosis have the potential to significantly improve the speed and accuracy of this process. This work presents a model to aid in the task of classification of structural Magnetic Resonance Imaging scans. The classification is performed using a Support Vector Machine, whilst the features to analyze belong to a dictionary space. Such space was mainly built from a dictionary learning perspective, although a predefined one was also assessed. The results indicate that features learnt from the data of interest lead to improved classification performance. The proposed framework was tested on the ADNI dataset stage I.


Subject(s)
Alzheimer Disease , Brain , Humans , Learning , Magnetic Resonance Imaging , Support Vector Machine
5.
Nucl Med Commun ; 39(3): 268-275, 2018 Mar.
Article in English | MEDLINE | ID: mdl-29346173

ABSTRACT

The Alderson striatal phantom is frequently used to assess I-FP-CIT (Ioflupane) image quality and to test semi-quantification software. However, its design is associated with a number of limitations, in particular: unrealistic image appearances and inflexibility. A new physical phantom approach is proposed on the basis of subresolution phantom technology. The design incorporates thin slabs of attenuating material generated through additive manufacturing, and paper sheets with radioactive ink patterns printed on their surface, created with a conventional inkjet printer. The paper sheets and attenuating slabs are interleaved before scanning. Use of thin layers ensures that they cannot be individually resolved on reconstructed images. An investigation was carried out to demonstrate the performance of such a phantom in producing simplified I-FP-CIT uptake patterns. Single photon emission computed tomography imaging was carried out on an assembled phantom designed to mimic a healthy patient. Striatal binding ratio results and linear striatal dimensions were calculated from the reconstructed data and compared with that of 22 clinical patients without evidence of Parkinsonian syndrome, determined from clinical follow-up. Striatal binding ratio results for the fully assembled phantom were: 3.1, 3.3, 2.9 and 2.6 for the right caudate, left caudate, right putamen and right caudate, respectively. All were within two SDs of results derived from a cohort of clinical patients. Medial-lateral and anterior-posterior dimensions of the simulated striata were also within the range of values seen in clinical data. This work provides the foundation for the generation of a range of more clinically realistic, physical phantoms.


Subject(s)
Cost-Benefit Analysis , Phantoms, Imaging/economics , Diagnostic Imaging , Printing , Tropanes
6.
Med Phys ; 43(9): 5020, 2016 Sep.
Article in English | MEDLINE | ID: mdl-27587032

ABSTRACT

PURPOSE: To make an adaptable, head shaped radionuclide phantom to simulate molecular imaging of the brain using clinical acquisition and reconstruction protocols. This will allow the characterization and correction of scanner characteristics, and improve the accuracy of clinical image analysis, including the application of databases of normal subjects. METHODS: A fused deposition modeling 3D printer was used to create a head shaped phantom made up of transaxial slabs, derived from a simulated MRI dataset. The attenuation of the printed polylactide (PLA), measured by means of the Hounsfield unit on CT scanning, was set to match that of the brain by adjusting the proportion of plastic filament and air (fill ratio). Transmission measurements were made to verify the attenuation of the printed slabs. The radionuclide distribution within the phantom was created by adding (99m)Tc pertechnetate to the ink cartridge of a paper printer and printing images of gray and white matter anatomy, segmented from the same MRI data. The complete subresolution sandwich phantom was assembled from alternate 3D printed slabs and radioactive paper sheets, and then imaged on a dual headed gamma camera to simulate an HMPAO SPECT scan. RESULTS: Reconstructions of phantom scans successfully used automated ellipse fitting to apply attenuation correction. This removed the variability inherent in manual application of attenuation correction and registration inherent in existing cylindrical phantom designs. The resulting images were assessed visually and by count profiles and found to be similar to those from an existing elliptical PMMA phantom. CONCLUSIONS: The authors have demonstrated the ability to create physically realistic HMPAO SPECT simulations using a novel head-shaped 3D printed subresolution sandwich method phantom. The phantom can be used to validate all neurological SPECT imaging applications. A simple modification of the phantom design to use thinner slabs would make it suitable for use in PET.


Subject(s)
Brain/diagnostic imaging , Phantoms, Imaging , Printing, Three-Dimensional , Tomography, Emission-Computed, Single-Photon/instrumentation , Magnetic Resonance Imaging
7.
Cochrane Database Syst Rev ; (6): CD010896, 2015 Jun 23.
Article in English | MEDLINE | ID: mdl-26102272

ABSTRACT

BACKGROUND: In the UK, dementia affects 5% of the population aged over 65 years and 25% of those over 85 years. Frontotemporal dementia (FTD) represents one subtype and is thought to account for up to 16% of all degenerative dementias. Although the core of the diagnostic process in dementia rests firmly on clinical and cognitive assessments, a wide range of investigations are available to aid diagnosis.Regional cerebral blood flow (rCBF) single-photon emission computed tomography (SPECT) is an established clinical tool that uses an intravenously injected radiolabelled tracer to map blood flow in the brain. In FTD the characteristic pattern seen is hypoperfusion of the frontal and anterior temporal lobes. This pattern of blood flow is different to patterns seen in other subtypes of dementia and so can be used to differentiate FTD.It has been proposed that a diagnosis of FTD, (particularly early stage), should be made not only on the basis of clinical criteria but using a combination of other diagnostic findings, including rCBF SPECT. However, more extensive testing comes at a financial cost, and with a potential risk to patient safety and comfort. OBJECTIVES: To determine the diagnostic accuracy of rCBF SPECT for diagnosing FTD in populations with suspected dementia in secondary/tertiary healthcare settings and in the differential diagnosis of FTD from other dementia subtypes. SEARCH METHODS: Our search strategy used two concepts: (a) the index test and (b) the condition of interest. We searched citation databases, including MEDLINE (Ovid SP), EMBASE (Ovid SP), BIOSIS (Ovid SP), Web of Science Core Collection (ISI Web of Science), PsycINFO (Ovid SP), CINAHL (EBSCOhost) and LILACS (Bireme), using structured search strategies appropriate for each database. In addition we searched specialised sources of diagnostic test accuracy studies and reviews including: MEDION (Universities of Maastricht and Leuven), DARE (Database of Abstracts of Reviews of Effects) and HTA (Health Technology Assessment) database.We requested a search of the Cochrane Register of Diagnostic Test Accuracy Studies and used the related articles feature in PubMed to search for additional studies. We tracked key studies in citation databases such as Science Citation Index and Scopus to ascertain any further relevant studies. We identified 'grey' literature, mainly in the form of conference abstracts, through the Web of Science Core Collection, including Conference Proceedings Citation Index and Embase. The most recent search for this review was run on the 1 June 2013.Following title and abstract screening of the search results, full-text papers were obtained for each potentially eligible study. These papers were then independently evaluated for inclusion or exclusion. SELECTION CRITERIA: We included both case-control and cohort (delayed verification of diagnosis) studies. Where studies used a case-control design we included all participants who had a clinical diagnosis of FTD or other dementia subtype using standard clinical diagnostic criteria. For cohort studies, we included studies where all participants with suspected dementia were administered rCBF SPECT at baseline. We excluded studies of participants from selected populations (e.g. post-stroke) and studies of participants with a secondary cause of cognitive impairment. DATA COLLECTION AND ANALYSIS: Two review authors extracted information on study characteristics and data for the assessment of methodological quality and the investigation of heterogeneity. We assessed the methodological quality of each study using the QUADAS-2 (Quality Assessment of Diagnostic Accuracy Studies) tool. We produced a narrative summary describing numbers of studies that were found to have high/low/unclear risk of bias as well as concerns regarding applicability. To produce 2 x 2 tables, we dichotomised the rCBF SPECT results (scan positive or negative for FTD) and cross-tabulated them against the results for the reference standard. These tables were then used to calculate the sensitivity and specificity of the index test. Meta-analysis was not performed due to the considerable between-study variation in clinical and methodological characteristics. MAIN RESULTS: Eleven studies (1117 participants) met our inclusion criteria. These consisted of six case-control studies, two retrospective cohort studies and three prospective cohort studies. Three studies used single-headed camera SPECT while the remaining eight used multiple-headed camera SPECT. Study design and methods varied widely. Overall, participant selection was not well described and the studies were judged as having either high or unclear risk of bias. Often the threshold used to define a positive SPECT result was not predefined and the results were reported with knowledge of the reference standard. Concerns regarding applicability of the studies to the review question were generally low across all three domains (participant selection, index test and reference standard).Sensitivities and specificities for differentiating FTD from non-FTD ranged from 0.73 to 1.00 and from 0.80 to 1.00, respectively, for the three multiple-headed camera studies. Sensitivities were lower for the two single-headed camera studies; one reported a sensitivity and specificity of 0.40 (95% confidence interval (CI) 0.05 to 0.85) and 0.95 (95% CI 0.90 to 0.98), respectively, and the other a sensitivity and specificity of 0.36 (95% CI 0.24 to 0.50) and 0.92 (95% CI 0.88 to 0.95), respectively.Eight of the 11 studies which used SPECT to differentiate FTD from Alzheimer's disease used multiple-headed camera SPECT. Of these studies, five used a case-control design and reported sensitivities of between 0.52 and 1.00, and specificities of between 0.41 and 0.86. The remaining three studies used a cohort design and reported sensitivities of between 0.73 and 1.00, and specificities of between 0.94 and 1.00. The three studies that used single-headed camera SPECT reported sensitivities of between 0.40 and 0.80, and specificities of between 0.61 and 0.97. AUTHORS' CONCLUSIONS: At present, we would not recommend the routine use of rCBF SPECT in clinical practice because there is insufficient evidence from the available literature to support this.Further research into the use of rCBF SPECT for differentiating FTD from other dementias is required. In particular, protocols should be standardised, study populations should be well described, the threshold for 'abnormal' scans predefined and clear details given on how scans are analysed. More prospective cohort studies that verify the presence or absence of FTD during a period of follow up should be undertaken.


Subject(s)
Cerebrovascular Circulation , Frontotemporal Dementia/diagnostic imaging , Tomography, Emission-Computed, Single-Photon/methods , Case-Control Studies , Cohort Studies , Dementia/diagnostic imaging , Diagnosis, Differential , Frontal Lobe/blood supply , Frontotemporal Dementia/physiopathology , Humans , Sensitivity and Specificity , Temporal Lobe/blood supply
8.
Neuroimage ; 81: 8-14, 2013 Nov 01.
Article in English | MEDLINE | ID: mdl-23664942

ABSTRACT

UNLABELLED: Traditional interpretation of rCBF SPECT data is of a qualitative nature and is dependent on the observer's understanding of the normal distribution of the tracer. The use of a normal database in quantitative regional analysis facilitates the detection of functional abnormality in individual and group studies by accounting for inter-subject variability. The ability to simulate realistic images would allow various important areas related to the use of normal databases to be studied. These include the optimisation of the detection of abnormal blood flow and the portability of normal databases between gamma camera systems. To investigate this further we have constructed a hardware phantom and scanned various configurations of radioactive brain patterns and simulated skull configurations. METHODS: A subresolution sandwich phantom was constructed with a simulated skull which was assembled using a high-resolution segmented MR scan printed with a (99m)TcO4 - mixture and scanned using a double-headed gamma camera with parallel-hole collimators. Various different grey-to-white matter (GM:WM) ratios and aluminium simulated skull configurations were used. A single difference measure between the phantom data and a control database mean image was used for optimisation. The realism of phantom data was assessed using statistical parametric mapping (SPM) and ROI analysis. RESULTS: Optimisation was achieved with a range of WM:GM ratios from 1.9 to 2.4:1 with various simulated skull configurations. CONCLUSION: The ability to simulate realistic HMPAO SPECT scans has been demonstrated using a subresolution sandwich phantom. Further work, involving scanning the optimised phantom on different gamma camera systems and comparison with camera-specific normal databases should further refine the phantom configuration.


Subject(s)
Brain Mapping/methods , Phantoms, Imaging , Tomography, Emission-Computed, Single-Photon/methods , Adult , Aged , Aged, 80 and over , Brain/diagnostic imaging , Brain/physiology , Cerebrovascular Circulation/physiology , Female , Humans , Male , Middle Aged , Radiopharmaceuticals , Technetium Tc 99m Exametazime
10.
Eur J Cardiothorac Surg ; 36(5): 849-55, 2009 Nov.
Article in English | MEDLINE | ID: mdl-19692256

ABSTRACT

OBJECTIVE: Acute kidney injury (AKI) post-cardiac surgery is associated with mortality rates approaching 20%. The development of effective treatments is hindered by the poor homology between rodent models, the mainstay of research into AKI, and that which occurs in humans. This pilot study aims to characterise post-cardiopulmonary bypass (CPB) AKI in an animal model with potentially greater homology to cardiac surgery patients. METHODS AND RESULTS: Adult pigs, weighing 50-75 kg, underwent 2.5 h of CPB. Pigs undergoing saphenous vein grafting procedures served as controls. Pre-CPB measures of porcine renal function were within normal ranges for adult humans. The effect of CPB on renal function; a 25% reduction in (51)Cr-EDTA clearance (p=0.068), and a 33% reduction in creatinine clearance (p=0.043), was similar to those reported in clinical studies. CPB resulted in tubular epithelial injury (median NAG/creatinine ratio 2.6 u mmol(-1) (interquartile range (IQR): 0.81-5.43) post-CPB vs 0.48 u mmol(-1) (IQR: 0.37-0.97) pre-CPB, p=0.043) as well as glomerular and/or proximal tubular injury (median albumin/creatinine ratio 6.8 mg mmol(-1) (IQR: 5.45-13.06) post-CPB vs 1.10 mg mmol(-1) (IQR: 0.05-2.00) pre-CPB, p=0.080). Tubular injury scores were significantly higher in kidneys post-CPB (median score 2.0 (IQR: 1.0-2.0) relative to vein graft controls (median score 1.0 (IQR 1.0-1.0), p=0.019). AKI was associated with endothelial injury and activation, as demonstrated by reduced DBA (dolichos biflorus agglutinin) lectin and increased endothelin-1 and vascular cell adhesion molecule (VCAM) staining. CONCLUSIONS: The porcine model of post-CPB AKI shows significant homology to AKI in cardiac surgical patients. It links functional, urinary and histological measures of kidney injury and may offer novel insights into the mechanisms underlying post-CPB AKI.


Subject(s)
Acute Kidney Injury/etiology , Cardiopulmonary Bypass/adverse effects , Acute Kidney Injury/pathology , Acute Kidney Injury/physiopathology , Animals , Biomarkers/urine , Disease Models, Animal , Female , Glomerular Filtration Rate , Kidney Tubules/pathology , Pilot Projects , Sus scrofa
11.
J Phys Chem A ; 113(9): 1864-8, 2009 Mar 05.
Article in English | MEDLINE | ID: mdl-19196001

ABSTRACT

Twenty-five microwave lines were observed for cis-1,3,5-hexatriene (0.05 D dipole moment) and a smaller number for its three (13)C isotopomers in natural abundance. Ground-state rotational constants were fitted for all four species to a Watson-type rotational Hamiltonian for an asymmetric top (kappa = -0.9768). Vibration-rotation (alpha) constants were predicted with a B3LYP/cc-pVTZ model and used to adjust the ground-state rotational constants to equilibrium rotational constants. The small inertial defect for cis-hexatriene shows that the molecule is planar, despite significant H-H repulsion. The substitution method was applied to the equilibrium rotational constants to give a semiexperimental equilibrium structure for the C(6) backbone. This structure and one predicted with the B3LYP/cc-pVTZ model show structural evidence for increased pi-electron delocalization in comparison with butadiene, the first member of the polyene series.


Subject(s)
Electrons , Polyenes/chemistry , Isomerism , Microwaves , Molecular Structure , Rotation , Spectrum Analysis , Vibration
13.
Chronic Dis Can ; 27(2): 77-84, 2006.
Article in English | MEDLINE | ID: mdl-16867242

ABSTRACT

Community-based smoking cessation initiatives target large numbers of people, are highly visible and have the potential for great impact. Ontario's Quit Smoking (2002) Contest was evaluated one year after its implementation to measure behaviour change among adult smokers participating in the contest. The registration database of 15,521 contest participants provided the basis for a random sample of 700 participants throughout Ontario who were contacted for a follow-up telephone survey. A total of 347 surveys were completed, of which 60 percent were women. Almost one third (31.4 percent) of the survey respondents reported that they had not smoked since the start of the contest. Participation in the contest also may have delayed relapse by as much as fi ve months for 31.3 percent of respondents who resumed smoking. Older respondents, men, those who had previously attempted to quit and people who said their cessation "buddy" was helpful were more likely to stop smoking.


Subject(s)
Health Behavior , Health Promotion , Smoking Cessation/psychology , Smoking Prevention , Smoking/epidemiology , Adult , Aged , Competitive Behavior , Female , Humans , Interviews as Topic , Male , Middle Aged , Motivation , Ontario/epidemiology , Program Evaluation , Residence Characteristics , Surveys and Questionnaires
14.
Nucl Med Commun ; 26(12): 1099-106, 2005 Dec.
Article in English | MEDLINE | ID: mdl-16264357

ABSTRACT

AIM: To assess the role of 99mTc-hexamethylpropyleneamine oxime single-photon emission computed tomography (99mTc-HMPAO SPECT) imaging of the precuneus and medial temporal lobe in the individual patient with mild Alzheimer's disease and dementia with Lewy bodies (DLB) using statistical parametric mapping and visual image interpretation. METHODS: Thirty-four patients with mild late-onset Alzheimer's disease, 20 patients with early-onset Alzheimer's disease, 15 patients with DLB and 31 healthy controls were studied. All patients fulfilled appropriate clinical criteria; the DLB patients also had evidence of dopaminergic presynaptic terminal loss on 123I-N-omega-fluoropropyl-2beta-carbomethoxy-3beta-(4-iodophenyl)-tropane imaging. 99mTc-HMPAO SPECT brain scans were acquired on a multidetector gamma camera and images were assessed separately by visual interpretation and with SPM99. RESULTS: Statistical parametric maps were significantly more accurate than visual image interpretation in all disease categories. In patients with mild late-onset Alzheimer's disease, statistical parametric mapping demonstrated significant hypoperfusion to the precuneus in 59% and to the medial temporal lobe in 53%. Seventy-six per cent of these patients had a defect in either location. No controls had precuneal or medial temporal lobe hypoperfusion (specificity, 100%). Statistical parametric mapping also demonstrated 73% of patients with DLB to have precuneal abnormalities, but only 6% had medial temporal lobe involvement. CONCLUSION: These findings illustrate the capability of statistical parametric mapping to demonstrate reliable abnormalities in the majority, but not all, patients with either mild Alzheimer's disease or DLB. Precuneal hypoperfusion is not specific to Alzheimer's disease and is equally likely to be found in DLB. In this study, medial temporal hypoperfusion was significantly more common in Alzheimer's disease than in DLB. Statistical parametric maps appear to be considerably more reliable than simple visual interpretation of 99mTc-HMPAO images for these regions.


Subject(s)
Alzheimer Disease/pathology , Brain Mapping/methods , Lewy Body Disease/pathology , Technetium Tc 99m Exametazime/pharmacology , Temporal Lobe/anatomy & histology , Tomography, Emission-Computed, Single-Photon/methods , Adult , Aged , Aged, 80 and over , Brain/pathology , Case-Control Studies , Cerebral Cortex/anatomy & histology , Computational Biology , Data Interpretation, Statistical , Female , Humans , Iodine Radioisotopes , Male , Middle Aged , Models, Statistical , Perfusion , Software , Temporal Lobe/pathology , Tropanes
15.
Cancer Epidemiol Biomarkers Prev ; 13(5): 808-19, 2004 May.
Article in English | MEDLINE | ID: mdl-15159314

ABSTRACT

The melanocortin-1 receptor gene (MC1R) encodes a membrane-bound receptor protein that is central to melanin synthesis. The coding region of MC1R is highly polymorphic and associations of variants with pigmentation phenotypes and risk for cutaneous neoplasms have been reported. We sought to determine the distribution and frequency of MC1R variants and their relationship to pigmentation characteristics in 179 Caucasian controls from the United States. One hundred thirty-five (75.4%) subjects carried one or more variants, and we determined that carriage of the previously designated "red hair color" (RHC) alleles, R151C, R160W, and D294H was strongly associated with fair pigmentation phenotypes including light hair and eye color, tendency to burn, decreased tendency to tan, and freckling. We used SIFT software to define MC1R protein positions that were predicted intolerant to amino acid substitutions; detected variants that corresponded to intolerant substitutions were D84E, R142H, R151C, I155T, R160W, and D294H. Carriage of one or more of these putative functionally important variants or the frameshift variant ins86A was significantly associated with fair pigmentation phenotypes. Analyses limited to carriage of ins86A and the three non-RHC alleles identified by SIFT were attenuated and no longer reached statistical significance. This is the first study to describe MC1R variants among control subjects from the U.S. Our results indicate that the frequency of variants is similar to that previously observed among non-U.S. Caucasians. Risk variants defined by either the published literature or by evolutionary criteria are strongly and significantly associated with all fair pigmentation phenotypes that were measured.


Subject(s)
Genetic Predisposition to Disease , Genetic Variation , Melanoma/genetics , Polymorphism, Genetic , Receptor, Melanocortin, Type 1/genetics , Skin Neoplasms/genetics , Adult , Aged , Alleles , Case-Control Studies , Confidence Intervals , Female , Gene Frequency , Genotype , Humans , Male , Melanocytes/metabolism , Middle Aged , Odds Ratio , Probability , Prognosis , Sensitivity and Specificity , Skin Pigmentation/genetics
16.
Cancer Epidemiol Biomarkers Prev ; 11(8): 782-4, 2002 Aug.
Article in English | MEDLINE | ID: mdl-12163334

ABSTRACT

Human pigmentation, including eye color, has been associated with skin cancer risk. The P gene is the human homologue to the mouse pink-eye dilution locus and is responsible for oculocutaneous albinism type 2 and other phenotypes that confer eye hypopigmentation. The P gene is located on chromosome 15q11.2-q12, which is also the location of a putative eye pigmentation gene (EYCL3) inferred to exist by linkage analysis. Therefore, the P gene is a strong candidate for determination of human eye color. Using a sample of 629 normally pigmented individuals, we found that individuals were less likely to have blue or gray eyes if they had P gene variants Arg305Trp (P = 0.002), Arg419Gln (P = 0.001), or the combination of both variants (P = 0.003). These results suggest that P gene, in part, determines normal phenotypic variation in human eye color and may therefore represent an inherited biomarker of cutaneous cancer risk.


Subject(s)
Carrier Proteins/genetics , Chromosomes, Human, Pair 15/genetics , Eye Color/genetics , Genetic Markers , Genetic Predisposition to Disease , Melanoma/genetics , Membrane Proteins/genetics , Membrane Transport Proteins , Skin Neoplasms/genetics , White People , DNA Primers , Humans , Melanoma/etiology , Phenotype , Polymerase Chain Reaction , Risk Factors , Skin Neoplasms/etiology
17.
Cancer ; 94(8): 2248-55, 2002 Apr 15.
Article in English | MEDLINE | ID: mdl-12001124

ABSTRACT

BACKGROUND: Incidence of cutaneous melanoma continues to increase in the Caucasian population worldwide. Approximately 5% of melanoma patients develop additional primary melanoma. This rate is significantly higher than the estimated lifetime risk of an individual for developing the disease (1.4%). These features suggest that a genetic predisposition may underlie multiple primary melanomas (MPMs). Prior studies had identified CDKN2A mutations in a few MPM individuals. The objectives of this study were to determine the frequency of family history of melanoma in MPM cases, to characterize other clinical features including history of other cancer, and to determine the association with functional CDKN2A mutations. METHODS: This study used a case series design. All living patients who had been seen in the Pigmented Lesion Clinic at the University of Pennsylvania and who had more than one primary invasive malignant melanoma or an invasive primary followed by an in situ melanoma were eligible for participation. RESULTS: Individuals with MPM frequently had a family history of melanoma, dysplastic nevi (DN), and/or another cancer including basal cell carcinoma (BCC), and squamous cell carcinoma breast cancer, and a personal history of DN, and basal cell carcinoma. Germline mutations in CDKN2A gene were identified in 8 of 96 MPM cases (8.3%, 95% confidence interval, 6.7-9.9%). CONCLUSIONS: These data indicate that the presence of MPM is associated with a modest incidence of a family history of melanoma, DN, or BCC and a small association with CDKN2A mutations. Therefore, in addition to the MPM index case, other family members can benefit from screening and regular surveillance for melanoma, DN, and BCC.


Subject(s)
Dysplastic Nevus Syndrome/genetics , Genes, p16/physiology , Melanoma/genetics , Skin Neoplasms/genetics , Adolescent , Adult , Age of Onset , Aged , Aged, 80 and over , Breast Neoplasms/genetics , Carcinoma, Basal Cell/genetics , Carcinoma, Squamous Cell/genetics , DNA Mutational Analysis/methods , DNA Primers/chemistry , DNA, Neoplasm/metabolism , Dysplastic Nevus Syndrome/pathology , Female , Germ-Line Mutation , Humans , Male , Middle Aged , Pancreatic Neoplasms/genetics , Pedigree , Polymerase Chain Reaction
18.
Am J Hum Genet ; 70(3): 770-5, 2002 Mar.
Article in English | MEDLINE | ID: mdl-11833005

ABSTRACT

In mice and humans, binding of alpha-melanocyte--stimulating hormone to the melanocyte-stimulating--hormone receptor (MSHR), the protein product of melanocortin-1 receptor (MC1R) gene, leads to the synthesis of eumelanin. In the mouse, ligation of MSHR by agouti signaling protein (ASP) results in the production of pheomelanin. The role of ASP in humans is unclear. We sought to characterize the agouti signaling protein gene (ASIP) in a group of white subjects, to assess whether ASIP was a determinant of human pigmentation and whether this gene may be associated with increased melanoma risk. We found no evidence of coding-region sequence variation in ASIP, but detected a g.8818A-->G polymorphism in the 3' untranslated region. We genotyped 746 participants in a study of melanoma susceptibility for g.8818A-->G, by means of polymerase chain reaction and restriction fragment--length polymorphism analysis. Among the 147 healthy controls, the frequency of the G allele was.12. Carriage of the G allele was significantly associated with dark hair (odds ratio 1.8; 95% confidence interval [CI] 1.2--2.8) and brown eyes (odds ratio 1.9; 95% CI 1.3--2.8) after adjusting for age, gender, and disease status. ASIP g.8818A-->G was not associated independently with disease status. This is the first report of an association of ASIP with specific human pigmentation characteristics. It remains to be investigated whether the interaction of MC1R and ASIP can enhance prediction of human pigmentation and melanoma risk.


Subject(s)
Intercellular Signaling Peptides and Proteins , Pigmentation/genetics , Polymorphism, Genetic/genetics , Proteins/genetics , Aging , Agouti Signaling Protein , Eye Color/genetics , Female , Gene Frequency/genetics , Genetic Predisposition to Disease , Genotype , Hair Color/genetics , Humans , Male , Melanoma/genetics , Odds Ratio , Phenotype , Sex Characteristics , Skin Pigmentation/genetics , White People/genetics
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