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1.
J Med Educ Curric Dev ; 7: 2382120519893989, 2020.
Article in English | MEDLINE | ID: mdl-32064357

ABSTRACT

BACKGROUND: Formal goal-setting has been shown to enhance performance and improve educational experiences. We initiated a standardized goal-setting intervention for all residents rotating through a Geriatric Medicine rotation. OBJECTIVES: This study aims to describe the feasibility of a goal-setting intervention on a geriatric medicine rotation, the resources required, and the barriers to implementation. As well, this study aims to describe the learning goals residents created regarding content and quality. METHODS: A pilot goal-setting intervention was initiated. A goal-setting form was provided at the beginning of their rotation and reviewed at the end of the rotation. Residents were invited to complete an anonymous online survey to gather feedback on the initiative. Goals were analysed for content and quality. Feedback from the survey results was incorporated into the goal-setting process. RESULTS: Between March and December 2018, 26 of 44 residents completed the goal-setting initiative. Explanations for the poor adherence included limited protected time for faculty and residents to engage in coaching, its voluntary nature, and trainee absence during orientation. Reasons for difficulty in achieving goals included lack of faculty and trainee time and difficulty assisting residents in achieving goals when no clinical opportunities arose. Although only 59% of residents completed the intervention, if goal-setting took place, most of the goals were specific (71 of 77; 92%) and 35 of 77 (45.5%) goals were not related to medical knowledge. CONCLUSIONS: This pilot study outlines the successes and barriers of a brief goal-setting intervention during a Geriatric Medicine rotation. Adherence was limited; however, of those who did complete the intervention, the creation of specific goals with a short, structured goal-setting form was possible. To enhance the intervention, goal-setting form completion should be enforced and efforts should be made to engage in mid-rotation check-ins and coaching.

2.
BMC Geriatr ; 18(1): 39, 2018 02 02.
Article in English | MEDLINE | ID: mdl-29394886

ABSTRACT

BACKGROUND: Nursing home residents are frail, have multiple medical comorbidities, and are at high risk for delirium. Most of the existing evidence base on delirium is derived from studies in the acute in-patient population. We examine the association between clinical characteristics and medication use with the incidence of delirium during the nursing home stay. METHODS: This is a retrospective cohort study of 1571 residents from 12 nursing homes operated by a single care provider in Ontario, Canada. Residents were over the age of 55 and admitted between February 2010 and December 2015 with no baseline delirium and a minimum stay of 180 days. Residents with moderate or worse cognitive impairment at baseline were excluded. The baseline and follow-up characteristics of residents were collected from the Resident Assessment Instrument-Minimal Data Set 2.0 completed at admission and repeated quarterly until death or discharge. Multivariate logistic regression was used to identify characteristics and medication use associated with the onset of delirium. RESULTS: The incidence of delirium was 40.4% over the nursing home stay (mean LOS: 32 months). A diagnosis of dementia (OR: 2.54, p < .001), the presence of pain (OR: 1.64, p < .001), and the use of antipsychotics (OR: 1.87, p < .001) were significantly associated with the onset of delirium. Compared to residents who did not develop delirium, residents who developed a delirium had a greater increase in the use of antipsychotics and antidepressants over the nursing home stay. CONCLUSIONS: Dementia, the presence of pain, and the use of antipsychotics were associated with the onset of delirium. Pain monitoring and treatment may be important to decrease delirium in nursing homes. Future studies are necessary to examine the prescribing patterns in nursing homes and their association with delirium.


Subject(s)
Delirium/diagnosis , Delirium/psychology , Homes for the Aged/trends , Nursing Homes/trends , Aged , Aged, 80 and over , Antidepressive Agents/adverse effects , Antidepressive Agents/therapeutic use , Antipsychotic Agents/adverse effects , Antipsychotic Agents/therapeutic use , Cognitive Dysfunction/diagnosis , Cognitive Dysfunction/epidemiology , Cognitive Dysfunction/psychology , Cohort Studies , Comorbidity , Delirium/epidemiology , Female , Humans , Incidence , Long-Term Care/trends , Male , Ontario/epidemiology , Pain/diagnosis , Pain/epidemiology , Pain/psychology , Retrospective Studies
3.
J Drugs Dermatol ; 15(10): 1235-1237, 2016 Oct 01.
Article in English | MEDLINE | ID: mdl-27741341

ABSTRACT

Telogen effluvium is one of the most common forms of non-scarring alopecia for which patients present to a dermatologist. It is a challenging disorder to treat and study, primarily owing to its multifactorial etiology which includes both physiologic and non-physiologic factors. Nutritional deficiency has been purported to contribute to hair shedding, and a patient's clinical history usually aids in directing laboratory evaluation. Many prior studies have either supported or failed to find a correlation between telogen effluvium and deficiencies in vitamins and minerals, in particular, vitamin D, ferritin, vitamin B12, folate, and zinc. We performed a retrospective cross-sectional study of patients with telogen effluvium in the greater Pittsburgh, Pennsylvania area, and measured the rates of these deficiencies. Our results demonstrate that the prevalence of vitamin D, ferritin, and zinc deficiencies is non-trivial and therefore justifies including these laboratory studies in initial clinical evaluation.

J Drugs Dermatol. 2016;15(10):1235-1237.


Subject(s)
Alopecia/diagnosis , Alopecia/epidemiology , Ferritins/deficiency , Vitamin D Deficiency/diagnosis , Vitamin D Deficiency/epidemiology , Zinc/deficiency , Adolescent , Adult , Aged , Aged, 80 and over , Alopecia/blood , Avitaminosis/diagnosis , Avitaminosis/epidemiology , Cross-Sectional Studies , Female , Ferritins/blood , Humans , Male , Middle Aged , Retrospective Studies , Trace Elements/blood , Trace Elements/deficiency , Vitamin D/blood , Vitamin D Deficiency/blood , Young Adult , Zinc/blood
4.
J Drugs Dermatol ; 14(10): 1161-2, 2015 Oct.
Article in English | MEDLINE | ID: mdl-26461830

ABSTRACT

Until 2011, the standard-of-care therapy for patients with hepatitis C consisted of interferon and ribavirin. The recent advent of new targeted therapies against this virus has provided more options of treatment for infected patients. Sofosbuvir, a nucleotide inhibitor of hepatitis C virus (HCV) RNA polymerase, was recently approved by the US Food and Drug Administration in 2013. Various Phase 3 trials with sofosbuvir combination therapy have reported an incidence of rash between 7% and 18%. We here describe a case of sofosbuvir-induced erythrodermic pityriasis rubra pilaris-like drug eruption.


Subject(s)
Antiviral Agents/adverse effects , Pityriasis Rubra Pilaris/chemically induced , Sofosbuvir/adverse effects , Antiviral Agents/therapeutic use , Drug Eruptions/etiology , Drug Eruptions/pathology , Hepatitis C/drug therapy , Humans , Male , Middle Aged , Pityriasis Rubra Pilaris/pathology , Sofosbuvir/therapeutic use
6.
Clin Endocrinol (Oxf) ; 81(2): 190-6, 2014 Aug.
Article in English | MEDLINE | ID: mdl-24735350

ABSTRACT

BACKGROUND: 22q11.2 deletion syndrome (22q11.2DS) is a relatively common yet under-recognized genetic syndrome that may present with endocrine features. We aimed to address the factors that contribute to the high prevalence of hypocalcaemia. METHODS: We investigated hypocalcaemia in a well-characterized sample of 138 adults with 22q11.2DS (65 m, 73 F; mean age 34.2, SD 11.8, years) using laboratory studies and lifelong medical records. Logistic regression modelling was used to identify features associated with lifetime prevalence of hypocalcaemia. RESULTS: Of the total sample, 111 (80.4%) had a lifetime history of hypocalcaemia. Eleven (84.6%) of 13 subjects with neonatal hypocalcaemia had documented recurrence of hypocalcaemia. Lifetime history of hypocalcaemia was associated with lifetime prevalence of hypoparathyroidism (P < 0.0001) and hypothyroidism (P = 0.04), as statistically independent factors. Hypomagnesaemia was associated with concurrent hypocalcaemic measurements, especially in the presence of concurrent hypoparathyroidism (P = 0.02). CONCLUSIONS: The results suggest that, in addition to the major effect of hypoparathyroidism, hypothyroidism may play a role in hypocalcaemia in 22q11.2DS and that there is a high recurrence rate of neonatal hypocalcaemia. Hypomagnesaemia may contribute to hypocalcaemia by further suppressing parathyroid hormone (PTH). Although further studies are needed, the findings support regular lifelong follow-up of calcium, magnesium, PTH and TSH levels in patients with 22q11.2DS. At any age, hypocalcaemia with hypoparathyroidism and/or hypothyroidism may suggest a diagnosis of 22q11.2DS.


Subject(s)
DiGeorge Syndrome/epidemiology , Hypocalcemia/epidemiology , Adult , DiGeorge Syndrome/physiopathology , Female , Humans , Hypocalcemia/physiopathology , Logistic Models , Male , Middle Aged , Prevalence , Retrospective Studies
7.
Genet Med ; 16(1): 40-4, 2014 Jan.
Article in English | MEDLINE | ID: mdl-23765047

ABSTRACT

PURPOSE: Hypocalcemia is a common endocrinological condition in 22q11.2 deletion syndrome. Neonatal hypocalcemia may affect neurodevelopment. We hypothesized that neonatal hypocalcemia would be associated with rare, more severe forms of intellectual disability in 22q11.2 deletion syndrome. METHODS: We used a logistic regression model to investigate potential predictors of intellectual disability severity, including neonatal hypocalcemia, neonatal seizures, and complex congenital heart disease, e.g., interrupted aortic arch, in 149 adults with 22q11.2 deletion syndrome. Ten subjects had moderate-to-severe intellectual disability. RESULTS: The model was highly significant (P < 0.0001), showing neonatal seizures (P = 0.0018) and neonatal hypocalcemia (P = 0.047) to be significant predictors of a more severe level of intellectual disability. Neonatal seizures were significantly associated with neonatal hypocalcemia in the entire sample (P < 0.0001), regardless of intellectual level. There was no evidence for the association of moderate-to-severe intellectual disability with other factors such as major structural brain malformations in this sample. CONCLUSION: The results suggest that neonatal seizures may increase the risk for more severe intellectual deficits in 22q11.2 deletion syndrome, likely mediated by neonatal hypocalcemia. Neonatal hypocalcemia often remains unrecognized until the postseizure period, when damage to neurons may already have occurred. These findings support the importance of early recognition and treatment of neonatal hypocalcemia and potentially neonatal screening for 22q11.2 deletions.


Subject(s)
DiGeorge Syndrome/physiopathology , Hypocalcemia/physiopathology , Intellectual Disability/physiopathology , Seizures/physiopathology , DiGeorge Syndrome/diagnosis , Female , Humans , Infant, Newborn , Logistic Models , Male , Neonatal Screening , Risk Factors , Young Adult
8.
Plast Reconstr Surg Glob Open ; 1(6): e47, 2013 Sep.
Article in English | MEDLINE | ID: mdl-25289241

ABSTRACT

BACKGROUND: Conventional autologous skin grafts are associated with significant donor-site morbidity. This study was conducted to determine feasibility, safety, and efficacy of a new strategy for skin grafting based on harvesting small columns of full-thickness skin with minimal donor-site morbidity. METHODS: The swine model was used for this study. Hundreds of full-thickness columns of skin tissue (~700 µm diameter) were harvested using a custom-made harvesting device, and then applied directly to excisional skin wounds. Healing in donor and graft sites was evaluated over 3 months by digital photographic measurement of wound size and blinded, computer-aided evaluation of histological features and compared with control wounds that healed by secondary intention or with conventional split-thickness skin grafts (STSG). RESULTS: After harvesting hundreds of skin columns, the donor sites healed rapidly without scarring. These sites reepithelialized within days and were grossly and histologically indistinguishable from normal skin within 7 weeks. By contrast, STSG donor sites required 2 weeks for reepithelialization and retained scar-like characteristics in epidermal and dermal architecture throughout the experiment. Wounds grafted with skin columns resulted in accelerated reepithelialization compared with ungrafted wounds while avoiding the "fish-net" patterning caused by STSG. CONCLUSION: Full-thickness columns of skin can be harvested in large quantities with negligible long-term donor-site morbidity, and these columns can be applied directly to skin wounds to enhance wound healing.

9.
J Virol ; 83(20): 10644-52, 2009 Oct.
Article in English | MEDLINE | ID: mdl-19706716

ABSTRACT

Murine gammaherpesvirus 68 (MHV-68) contains a ubiquitin (Ub)-specific cysteine protease (USP) domain embedded within the large tegument protein ORF64, as do all other herpesviruses. The biological role of this protease is still unclear, but for the alphaherpesvirus Marek's disease virus, its USP is involved in T-cell lymphoma formation. We here study the role of the MHV-68 USP, encoded by ORF64. By constructing a mutant virus with a single cysteine-to-alanine replacement in the active site of ORF64, we demonstrate that the USP activity of ORF64 is abolished. The mutant virus replicates less efficiently in vitro, and plaque size is reduced compared to that of a revertant virus. Electron microscopy of infected cells did not reveal any obvious differences in virion morphogenesis or differences in egress for the mutant and revertant viruses. Intraperitoneal infection of C57/BL6 mice demonstrates that the mutant virus is generally cleared by day 7, indicating a role for the USP in the persistence of MHV-68 infection or efficient replication. However, the USP activity in MHV-68 is unlikely to be involved in the establishment of latency or reactivation, since we observed no significant difference in viral DNA genome copy number in the spleen or in the number of cells that reactivate MHV-68 from latency. Our results for MHV-68 ORF64 are consistent with an enzymatic function of the tegument protein that is beneficial to the virus during acute infection, particularly in vivo.


Subject(s)
Endopeptidases , Gammaherpesvirinae/enzymology , Gammaherpesvirinae/pathogenicity , Herpesviridae Infections/pathology , Open Reading Frames , Animals , Cell Line , Endopeptidases/genetics , Endopeptidases/metabolism , Gammaherpesvirinae/genetics , Herpesviridae Infections/virology , Mice , Mice, Inbred C57BL , Microscopy, Electron , Mutation , Open Reading Frames/genetics , Open Reading Frames/physiology , Ubiquitin-Specific Proteases , Viral Plaque Assay , Viral Proteins/genetics , Viral Proteins/metabolism
10.
J Virol ; 82(24): 12205-12, 2008 Dec.
Article in English | MEDLINE | ID: mdl-18922872

ABSTRACT

Infection of mice with murine gammaherpesvirus 68 (MHV-68) robustly activates CD8 T cells, but only six class I major histocompatibility complex (MHC)-restricted epitopes have been described to date for the widely used H-2(b) haplotype mice. To explore the specificity and kinetics of the cytotoxic T-lymphocyte response in MHV-68-infected C57BL/6 mice, we screened for H-2K(b)- and H-2D(b)-restricted epitopes using a set of 384 candidate epitopes in an MHC tetramer-based approach and identified 19 new epitopes in 16 different open reading frames. Of the six known H-2K(b)- and H-2D(b)-restricted epitopes, we confirmed a response against three and did not detect CD8 T-cell-specific responses for the remaining three. The peak of the CD8 T-cell response to most peptides occurs between 6 and 10 days postinfection. The respective MHC tetramer-positive CD8 T cells display an activated/effector phenotype (CD62L(lo) and CD44(hi)) and produce gamma interferon upon peptide stimulation ex vivo. MHV-68 infection in vivo elicits a response to multiple viral epitopes, derived from both early and late viral antigens, illustrating a far broader T-cell repertoire and more-rapid activation than those previously recorded.


Subject(s)
Antigens/immunology , CD8-Positive T-Lymphocytes/immunology , Epitopes, T-Lymphocyte/immunology , Rhadinovirus/immunology , Animals , Genome, Viral/immunology , Herpesviridae Infections/immunology , Herpesviridae Infections/virology , Kinetics , Mice , Mice, Inbred C57BL , Time Factors
11.
Mol Biol Cell ; 19(4): 1587-93, 2008 Apr.
Article in English | MEDLINE | ID: mdl-18256279

ABSTRACT

In mammals the transfer of passive immunity from mother to young is mediated by the MHC-related receptor FcRn, which transports maternal IgG across epithelial cell barriers. In birds, maternal IgY in egg yolk is transferred across the yolk sac to passively immunize chicks during gestation and early independent life. The chicken yolk sac IgY receptor (FcRY) is the ortholog of the mammalian phospholipase A2 receptor, a mannose receptor family member, rather than an FcRn or MHC homolog. FcRn and FcRY both exhibit ligand binding at the acidic pH of endosomes and ligand release at the slightly basic pH of blood. Here we show that FcRY expressed in polarized mammalian epithelial cells functioned in endocytosis, bidirectional transcytosis, and recycling of chicken FcY/IgY. Confocal immunofluorescence studies demonstrated that IgY binding and endocytosis occurred at acidic but not basic pH, mimicking pH-dependent uptake of IgG by FcRn. Colocalization studies showed FcRY-mediated internalization via clathrin-coated pits and transport involving early and recycling endosomes. Disruption of microtubules partially inhibited apical-to-basolateral and basolateral-to-apical transcytosis, but not recycling, suggesting the use of different trafficking machinery. Our results represent the first cell biological evidence of functional equivalence between FcRY and FcRn and provide an intriguing example of how evolution can give rise to systems in which similar biological requirements in different species are satisfied utilizing distinct protein folds.


Subject(s)
Immunoglobulins/metabolism , Lectins, C-Type/metabolism , Mannose-Binding Lectins/metabolism , Receptors, Cell Surface/metabolism , Receptors, Fc/metabolism , Yolk Sac/immunology , Animals , Cell Line , Cell Polarity , Chick Embryo , Endocytosis/immunology , Epithelial Cells/cytology , Epithelial Cells/immunology , Epithelial Cells/metabolism , Female , Histocompatibility Antigens Class I/genetics , Histocompatibility Antigens Class I/metabolism , Immunization, Passive , Kidney Tubules, Collecting/cytology , Kidney Tubules, Collecting/immunology , Kidney Tubules, Collecting/metabolism , Lectins, C-Type/genetics , Mannose Receptor , Mannose-Binding Lectins/genetics , Rats , Receptors, Cell Surface/genetics , Receptors, Fc/genetics , Receptors, Phospholipase A2/genetics , Receptors, Phospholipase A2/metabolism , Recombinant Proteins/genetics , Recombinant Proteins/metabolism , Transfection , Yolk Sac/metabolism
12.
J Virol ; 82(7): 3490-9, 2008 Apr.
Article in English | MEDLINE | ID: mdl-18216124

ABSTRACT

Recognition of immunoglobulin G (IgG) by surface receptors for the Fc domain of immunoglobulin G (Fcgamma), FcgammaRs, can trigger both humoral and cellular immune responses. Two human cytomegalovirus (HCMV)-encoded type I transmembrane receptors with Fcgamma-binding properties (vFcgammaRs), gp34 and gp68, have been identified on the surface of HCMV-infected cells and are assumed to confer protection against IgG-mediated immunity. Here we show that Fcgamma recognition by both vFcgammaRs occurs independently of N-linked glycosylation of Fcgamma, in contrast with the properties of host FcgammaRs. To gain further insight into the interaction with Fcgamma, truncation mutants of the vFcgammaR gp68 ectodomain were probed for Fcgamma binding, resulting in localization of the Fcgamma binding site on gp68 to residues 71 to 289, a region including an immunoglobulin-like domain. Gel filtration and biosensor binding experiments revealed that, unlike host FcgammaRs but similar to the herpes simplex virus type 1 (HSV-1) Fc receptor gE-gI, gp68 binds to the C(H)2-C(H)3 interdomain interface of the Fcgamma dimer with a nanomolar affinity and a 2:1 stoichiometry. Unlike gE-gI, which binds Fcgamma at the slightly basic pH of the extracellular milieu but not at the acidic pH of endosomes, the gp68/Fcgamma complex is stable at pH values from 5.6 to pH 8.1. These data indicate that the mechanistic details of Fc binding by HCMV gp68 differ from those of host FcgammaRs and from that of HSV-1 gE-gI, suggesting distinct functional and recognition properties.


Subject(s)
Cytomegalovirus/physiology , Immunoglobulin G/metabolism , Membrane Glycoproteins/metabolism , Protein Interaction Mapping , Receptors, IgG/metabolism , Viral Proteins/metabolism , Animals , Binding Sites , Carrier Proteins/chemistry , Carrier Proteins/metabolism , Cell Line , Chlorocebus aethiops , Chromatography, Gel , Glycoproteins/chemistry , Glycoproteins/metabolism , Humans , Hydrogen-Ion Concentration , Immunoglobulin G/chemistry , Immunoprecipitation , Kinetics , Membrane Glycoproteins/chemistry , Membrane Glycoproteins/genetics , Protein Binding , Receptors, IgG/chemistry , Receptors, IgG/genetics , Sequence Deletion , Surface Plasmon Resonance , Viral Proteins/chemistry , Viral Proteins/genetics
13.
Genes Dev ; 21(22): 2880-96, 2007 Nov 15.
Article in English | MEDLINE | ID: mdl-17978103

ABSTRACT

Myb-MuvB (MMB)/dREAM is a nine-subunit complex first described in Drosophila as a repressor of transcription, dependent on E2F2 and the RBFs. Myb, an integral member of MMB, curiously plays no role in the silencing of the test genes previously analyzed. Moreover, Myb plays an activating role in DNA replication in Drosophila egg chamber follicle cells. The essential functions for Myb are executed as part of MMB. This duality of function lead to the hypothesis that MMB, which contains both known activator and repressor proteins, might function as part of a switching mechanism that is dependent on DNA sites and developmental context. Here, we used proliferating Drosophila Kc tissue culture cells to explore both the network of genes regulated by MMB (employing RNA interference and microarray expression analysis) and the genomic locations of MMB following chromatin immunoprecipitation (ChIP) and tiling array analysis. MMB occupied 3538 chromosomal sites and was promoter-proximal to 32% of Drosophila genes. MMB contains multiple DNA-binding factors, and the data highlighted the combinatorial way by which the complex was targeted and utilized for regulation. Interestingly, only a subset of chromatin-bound complexes repressed genes normally expressed in a wide range of developmental pathways. At many of these sites, E2F2 was critical for repression, whereas at other nonoverlapping sites, Myb was critical for repression. We also found sites where MMB was a positive regulator of transcript levels that included genes required for mitotic functions (G2/M), which may explain some of the chromosome instability phenotypes attributed to loss of Myb function in myb mutants.


Subject(s)
Caspases/metabolism , Cell Cycle Proteins/metabolism , Cell Proliferation , Drosophila Proteins/metabolism , Drosophila/metabolism , Gene Expression Profiling/methods , Gene Expression , Proto-Oncogene Proteins c-myb/metabolism , Animals , Caspases/genetics , Cell Cycle Proteins/genetics , Cells, Cultured , Chromatin Immunoprecipitation , Drosophila/cytology , Drosophila Proteins/genetics , Genome, Insect , Models, Biological , Oligonucleotide Array Sequence Analysis , Proto-Oncogene Proteins c-myb/genetics , RNA Interference
14.
Science ; 316(5830): 1484-8, 2007 Jun 08.
Article in English | MEDLINE | ID: mdl-17510325

ABSTRACT

Significant fractions of eukaryotic genomes give rise to RNA, much of which is unannotated and has reduced protein-coding potential. The genomic origins and the associations of human nuclear and cytosolic polyadenylated RNAs longer than 200 nucleotides (nt) and whole-cell RNAs less than 200 nt were investigated in this genome-wide study. Subcellular addresses for nucleotides present in detected RNAs were assigned, and their potential processing into short RNAs was investigated. Taken together, these observations suggest a novel role for some unannotated RNAs as primary transcripts for the production of short RNAs. Three potentially functional classes of RNAs have been identified, two of which are syntenically conserved and correlate with the expression state of protein-coding genes. These data support a highly interleaved organization of the human transcriptome.


Subject(s)
Genome, Human , RNA Precursors/genetics , RNA, Messenger/genetics , RNA, Messenger/metabolism , RNA/genetics , Transcription, Genetic , Animals , Cell Line, Tumor , Cell Nucleus/metabolism , Cytosol/metabolism , Exons , Gene Expression , Genome , HeLa Cells , Humans , Mice , Promoter Regions, Genetic , RNA/metabolism , RNA Precursors/metabolism , Synteny , Terminator Regions, Genetic
15.
Cancer Res ; 64(18): 6394-401, 2004 Sep 15.
Article in English | MEDLINE | ID: mdl-15374946

ABSTRACT

To determine whether cancer risk is related to histopathological features of preneoplastic aberrant crypt foci (ACF), gene expression analysis was performed on ACF from two mouse strains with differing tumor sensitivity to the colonotropic carcinogen, azoxymethane. ACF from sensitive A/J mice were considered at high risk, whereas ACF from resistant AKR/J mice were considered at low risk for tumorigenesis. A/J and AKR/J mice received weekly injections of azoxymethane (10 mg/kg body weight), and frozen colon sections were prepared 6 weeks later. Immunohistochemistry was performed using biomarkers associated with colon cancer, including adenomatous polyposis coli, beta-catenin, p53, c-myc, cyclin D1, and proliferating cell nuclear antigen. Hyperplastic ACF, dysplastic ACF, microadenomas, adjacent normal-appearing epithelium, and vehicle-treated colons were laser captured, and RNA was linearly amplified (LCM-LA) and subjected to cDNA microarray-based expression analysis. Patterns of gene expression were identified using adaptive centroid algorithm. ACF from low- and high-risk colons were not discriminated by immunohistochemistry, with the exception of membrane staining of beta-catenin. To develop genetic signatures that predict cancer risk, LCM-LA RNA from ACF was hybridized to cDNA arrays. Of 4896 interrogated genes, 220 clustered into six broad clusters. A total of 226 and 202 genes was consistently altered in lesions from A/J and AKR/J mice, respectively. Although many alterations were common to both strains, expression profiles stratified high- and low- risk lesions. These data demonstrate that ACF with distinct tumorigenic potential have distinguishing molecular features. In addition to providing insight into colon cancer promotion, our data identify potential biomarkers for determining colon cancer risk in humans.


Subject(s)
Colonic Neoplasms/genetics , Precancerous Conditions/genetics , Animals , Biomarkers, Tumor/biosynthesis , Biomarkers, Tumor/genetics , Colon/pathology , Colonic Neoplasms/metabolism , Colonic Neoplasms/pathology , Disease Models, Animal , Gene Expression Profiling , Genetic Predisposition to Disease , Hyperplasia , Immunohistochemistry , Male , Mice , Mice, Inbred AKR , Precancerous Conditions/metabolism , Precancerous Conditions/pathology
16.
Cytometry A ; 59(2): 254-61, 2004 Jun.
Article in English | MEDLINE | ID: mdl-15170605

ABSTRACT

BACKGROUND: Since the sequencing of the human genome has been finished, microgenomics has been booming, employing highly sophisticated, high-throughput platforms. But these mainly chip-based methods can only generate biologically relevant data if the samples investigated consist of homogeneous cell populations, in which no unwanted cells of different specificity and/or developmental stage obscure the results. METHODS: Different sampling methods have been routinely applied to overcome the problem presented by heterogeneous samples, e.g., global surveys, cell cultures, and microdissection. Various methods of laser-assisted microdissection, employing either positive or negative selection of tissue areas or even single cells, are available. RESULTS: These laser-assisted microdissection methods allow for fast and precise procurement of extremely small samples. Through subsequent application of recently developed methods of linear mRNA amplification in a pool of isolated total RNA, it has now become possible to perform complex high-throughput RNA expression profiling by microdissecting and processing even single-cell samples. CONCLUSIONS: Studies using the tools and methods of microgenomics have shed light on how those new approaches will eventually aid in the development of a new generation of diagnostics, e.g., leading to new patient-specific drugs tailored to the requirements assessed by assaying only a few biopsy cells.


Subject(s)
Cell Separation/methods , Cytogenetic Analysis/methods , Gene Expression Profiling , Genomics/methods , RNA, Messenger/analysis , Humans , Lasers , Microdissection/methods , RNA, Messenger/genetics
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