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1.
Transplant Proc ; 51(3): 722-728, 2019 Apr.
Article in English | MEDLINE | ID: mdl-30979456

ABSTRACT

TruGraf v1 is a laboratory-developed DNA microarray-based gene expression blood test to enable proactive noninvasive serial assessment of kidney transplant recipients with stable renal function. It has been previously validated in patients identified as Transplant eXcellence (TX: stable serum creatinine, normal biopsy results, indicative of immune quiescence), and not-TX (renal dysfunction and/or rejection on biopsy results). TruGraf v1 is intended for use in subjects with stable renal function to measure the immune status as an alternative to invasive, expensive, and risky surveillance biopsies. MATERIALS AND METHODS: In this study, simultaneous blood tests and clinical assessments were performed in 192 patients from 7 transplant centers to evaluate TruGraf v1. The molecular testing laboratory was blinded to renal function and biopsy results. RESULTS: Overall, TruGraf v1 accuracy (concordance between TruGraf v1 result and clinical and/or histologic assessment) was 74% (142/192), and a result of TX was accurate in 116 of 125 (93%). The negative predictive value for TruGraf v1 was 90%, with a sensitivity 74% and specificity of 73%. Results did not significantly differ in patients with a biopsy-confirmed diagnosis vs those without a biopsy. CONCLUSIONS: TruGraf v1 can potentially support a clinical decision enabling unnecessary surveillance biopsies with high confidence, making it an invaluable addition to the transplant physician's tool kit for managing patients. TruGraf v1 testing can potentially avoid painful and risky invasive biopsies, reduce health care costs, and enable frequent assessment of patients with stable renal function to confirm the presence of immune quiescence in the peripheral blood.


Subject(s)
Gene Expression Profiling/methods , Graft Rejection/diagnosis , Kidney Transplantation , Oligonucleotide Array Sequence Analysis/methods , Adult , Biopsy , Female , Graft Rejection/immunology , Humans , Male , Middle Aged , Retrospective Studies , Sensitivity and Specificity , Transplant Recipients
2.
Transplant Proc ; 51(3): 729-733, 2019 Apr.
Article in English | MEDLINE | ID: mdl-30979457

ABSTRACT

BACKGROUND: TruGraf v1 is a well-validated DNA microarray-based test that analyzes blood gene expression profiles as an indicator of immune status in kidney transplant recipients with stable renal function. METHODS: In this study, investigators assessed clinical utility of the TruGraf test in patient management. In a retrospective study, simultaneous blood tests and clinical assessments were performed in 192 patients at 7 transplant centers, and in a prospective observational study they were performed in 45 subjects at 5 transplant centers. RESULTS: When queried regarding whether or not the TruGraf test result impacted their decision regarding patient management, in 168 of 192 (87.5%) cases the investigator responded affirmatively. The prospective study indicated that TruGraf results supported physicians' decisions on patient management 87% (39/45) of the time, and in 93% of cases physicians indicated that they would use serial TruGraf testing in future patient management. A total of 21 of 39 (54%) reported results confirmed their decision that no intervention was needed, and 17 of 39 (44%) reported that results specifically informed them that a decision not to perform a surveillance biopsy was correct. CONCLUSIONS: TruGraf is the first and only noninvasive test to be evaluated for clinical utility in determining rejection status of patients with stable renal function and shows promise of providing support for clinical decisions to avoid unnecessary surveillance biopsies with a high degree of confidence. TruGraf is an invaluable addition to the transplant physician's tool kit for managing patient health by avoiding painful and invasive biopsies, reducing health care costs, and enabling frequent assessment of patients with stable renal function to confirm immune quiescence.


Subject(s)
Gene Expression Profiling/methods , Graft Rejection/diagnosis , Kidney Transplantation , Oligonucleotide Array Sequence Analysis/methods , Biopsy , Decision Making , Female , Graft Rejection/blood , Graft Rejection/immunology , Humans , Male , Middle Aged , Pathology, Molecular/methods , Physicians , Prospective Studies , Retrospective Studies
3.
J Laryngol Otol ; 130(4): 329-31, 2016 Apr.
Article in English | MEDLINE | ID: mdl-26781772

ABSTRACT

Kevin Kane has written about the painting by Barbara Hepworth of Garnett Passe performing a tonsillectomy, and wondered about the way in which the gag appears to be suspended. This article traces historically the various methods of holding the gag for tonsillectomy, and postulates that what is illustrated in the Hepworth painting is a jack owned by the late Dr Sydney Cocks, who not only was a friend of Passe but who also commenced the discussions with Passe's widow, Barbara, concerning the formation by her of a trust to support young Australian ENT surgeons, which eventually became The Garnett Passe and Rodney Williams Memorial Foundation.


Subject(s)
Medical Illustration/history , Paintings/history , Tonsillectomy/history , Australia , Foundations/history , History, 20th Century , Humans , Reflex/physiology , Tonsillectomy/instrumentation
4.
S Afr Med J ; 105(6): 496-9, 2015 Jun.
Article in English | MEDLINE | ID: mdl-26716170

ABSTRACT

BACKGROUND: Present limitations in primary and secondary prevention of diabetic retinopathy mean that many patients with diabetes present with advanced retinal complications, often requiring surgery (vitrectomy). OBJECTIVES: To determine the outcomes of vitrectomy for advanced diabetic retinopathy and to examine context-specific risk factors that may influence outcomes and decisions affecting resource allocation. METHODS: This was a retrospective cohort study of 124 vitrectomies with up to 6 months' follow-up. RESULTS: Visual acuity was 6/60 or worse in the better eye in 23.4% of patients at presentation. The mean visual acuity of the listed eye was 2/60. The fellow eye was considered inoperable in 20.2% of cases. Visual function declined significantly in 26.2% of patients while awaiting surgery. The average waiting time until surgery was 2.9 months (range 1 day - 9 months). Epiretinal membranes were present in 93.6% of cases, and posterior iatrogenic breaks occurred in 49.2%. Silicone oil was used in 24.2%. Visual acuity improved in 54.9%, was unchanged in 30.1%, and worsened in 14.0% of cases at 6 months. Patients with poorer vision at surgery were more likely to improve (odds ratio 2.15; p=0.048). Factors associated with a worse visual outcome were increased age at surgery (p=0.042) and posterior iatrogenic retinal breaks (p=0.007). Renal dysfunction was not associated with worse visual outcomes. CONCLUSION: Vitrectomy improved or stabilised vision in 85.0% of cases, although outcomes were unpredictable. A long waiting time to surgery contributed to patient morbidity. The presence of renal dysfunction did not predict poorer visual outcomes.

5.
Osteoporos Int ; 21(11): 1881-8, 2010 Nov.
Article in English | MEDLINE | ID: mdl-20135095

ABSTRACT

UNLABELLED: Using a single bone mineral density (BMD) measure, we demonstrated that the lower limit of normal (LLN) method is more consistent in predicting osteoporosis fractures than the T-score in white menopausal women from the Study of Osteoporosis Fracture (SOF). INTRODUCTION: In order to circumvent the inconsistencies and limitations with using the T-score when defining osteoporosis, we propose using 95% LLN values derived from centered polynomial models using the NHANES III BMD measures. The main aim of this study was to compare the two methods in prediction of fracture and agreement in osteoporosis classification using cohort data. METHODS: We compared the fracture prediction ability of the two methods using a single BMD measurement in 4,948 white women aged 67-74 years in the SOF employing kappa statistics, sensitivity, and specificity. RESULTS: The T-score provided inconsistent osteoporosis classification (46.6%) across the five hip regions of interest (ROIs) and this was significantly (p<0.0001) reduced when using the LLN method (36.5%). Kappa statistics of incident fracture during 12 years of follow-up related to the prevalence of osteoporosis at baseline was significantly improved using the LLN method compared to using T-score. Sensitivity and specificity for fracture based on a single BMD measurement of different hip ROIs were more consistent using the LLN method. CONCLUSION: The LLN method provides a more consistent and efficient method for osteoporosis fracture prediction than the T-score in 67- to 74-year-old white women.


Subject(s)
Bone Density/physiology , Osteoporotic Fractures/diagnosis , Absorptiometry, Photon/methods , Adult , Aged , Aging/physiology , Body Weight/physiology , Epidemiologic Methods , Female , Femur Neck/physiopathology , Hip Joint/physiopathology , Humans , Middle Aged , Osteoporosis, Postmenopausal/complications , Osteoporosis, Postmenopausal/epidemiology , Osteoporosis, Postmenopausal/physiopathology , Osteoporotic Fractures/epidemiology , Osteoporotic Fractures/etiology , Osteoporotic Fractures/physiopathology , Reference Values , Young Adult
6.
Eur J Clin Nutr ; 63(12): 1411-8, 2009 Dec.
Article in English | MEDLINE | ID: mdl-19707221

ABSTRACT

BACKGROUND/OBJECTIVES: Energy density (kJ/g) may have a strong influence on energy balance. Although beverages are a considerable source of energy in the United States diet, rarely have studies among free-living populations investigated the energy density of foods (EDF) and the energy density of beverages (EDB) simultaneously. We examined the independent simultaneous associations of EDF and EDB on energy intake and body mass index (BMI) in adult women. SUBJECTS/METHODS: This cross-sectional design focused on 348 elementary school employees randomly selected at baseline of a worksite wellness trial in southeastern Louisiana. Two 24-h recalls were collected, and measured heights and weights were converted into BMI (kg/m(2)). RESULTS: Those in the highest EDF tertile consumed more energy and had higher BMIs than those in the lowest tertile (P<0.05). Employees in the highest EDB tertile consumed more energy than those in the lowest, yet there was no difference in BMIs between the two groups. Multivariate regression, with controls for demographic and health variables, confirmed the positive association between EDF and BMI; a 1 kJ/g increase in EDF was associated with a 0.39 kg/m(2) increase in BMI (P=0.038). Models that did not control for EDB gave estimates of EDF that were 8-10% lower. CONCLUSIONS: These findings suggest that EDF and EDB have important, yet distinct, functions in energy intake and BMI. Future studies should evaluate both types of energy density as independent predictors as our results suggest that EDB can confound the association of EDF with BMI.


Subject(s)
Beverages/statistics & numerical data , Body Mass Index , Energy Intake/physiology , Faculty/statistics & numerical data , Food/statistics & numerical data , Adult , Cross-Sectional Studies , Diet/statistics & numerical data , Diet Surveys , Female , Humans , Louisiana , Middle Aged , Multivariate Analysis , Nutritive Value , Overweight/epidemiology , Overweight/etiology , Schools
7.
Acta Physiol (Oxf) ; 197(3): 187-96, 2009 Nov.
Article in English | MEDLINE | ID: mdl-19432593

ABSTRACT

AIM: Oestrogen receptors (ER) are present in human skeletal muscle (hSkM) cells; however, the function of the receptor is currently unknown. We investigated the influence of oestradiol and selective ER modulators [tamoxifen (TAM), raloxifene (RAL)] on ER coregulator mRNA expression in hSkM. METHODS: Human skeletal muscle cells were treated with 10 nm oestradiol, 5 microm TAM and 10 microm RAL over a 24-h period. Following the treatment period, mRNA expression was quantified using real-time PCR to detect changes in ER-alpha, ER-beta, steroid receptor coactivator (SRC), silencing mediator for retinoid and thyroid hormone receptors (SMRT), MyoD, GLUT4 and c-fos. RESULTS: ER-alpha mRNA expression increased with all three drug treatments (P < 0.05) while there was no change in mRNA expression of ER-beta in hSkM cells. mRNA expression of SRC increased and SMRT decreased with oestradiol, TAM and RAL in hSkM cells (P < 0.05). Importantly, mRNA expression of MyoD increased with oestradiol and decreased with TAM and RAL in hSkM cells (P < 0.05). mRNA expression of GLUT4 increased with oestradiol and RAL and decreased with TAM in hSkM cells (P < 0.05). CONCLUSIONS: These findings are novel in that they provide the first evidence that oestradiol and selective ER modulators influence ER-alpha function in hSkM cells. This demonstrates the importance of the ER and alterations in its coregulators, to potentially prevent sarcopenia and promote muscle growth in postmenopausal women using these forms of hormone replacement therapy.


Subject(s)
Estradiol/pharmacology , Muscle Cells/metabolism , Muscle, Skeletal/metabolism , Nuclear Receptor Co-Repressor 2/drug effects , Nuclear Receptor Coactivator 1/drug effects , Selective Estrogen Receptor Modulators/pharmacology , Gene Expression , Gene Expression Regulation/drug effects , Humans , Muscle Cells/drug effects , Muscle, Skeletal/drug effects , Nuclear Receptor Co-Repressor 2/biosynthesis , Nuclear Receptor Coactivator 1/biosynthesis , RNA, Messenger/analysis , Raloxifene Hydrochloride/pharmacology , Receptors, Estrogen/drug effects , Receptors, Estrogen/metabolism , Reverse Transcriptase Polymerase Chain Reaction , Tamoxifen/pharmacology
10.
Oncogene ; 27(31): 4293-304, 2008 Jul 17.
Article in English | MEDLINE | ID: mdl-18408754

ABSTRACT

Lethal 3 malignant brain tumor 1 (L3MBTL1), a homolog of the Drosophila polycomb tumor suppressor l(3)mbt, contains three tandem MBT repeats (3xMBT) that are critical for transcriptional repression. We recently reported that the 3xMBT repeats interact with mono- and dimethylated lysines in the amino termini of histones H4 and H1b to promote methylation-dependent chromatin compaction. Using a series of histone peptides, we now show that the recognition of mono- and dimethylated lysines in histones H3, H4 and H1.4 (but not their trimethylated or unmodified counterparts) by 3xMBT occurs in the context of a basic environment, requiring a conserved aspartic acid (D355) in the second MBT repeat. Despite the broad range of in vitro binding, the chromatin association of L3MBTL1 mirrors the progressive accumulation of H4K20 monomethylation during the cell cycle. Furthermore, transcriptional repression by L3MBTL1 is enhanced by the H4K20 monomethyltransferase PR-SET7 (to which it binds) but not SUV420H1 (an H4K20 trimethylase) or G9a (an H3K9 dimethylase) and knockdown of PR-SET7 decreases H4K20me1 levels and the chromatin association of L3MBTL1. Our studies identify the importance of H4K20 monomethylation and of PR-SET7 for L3MBTL1 function.


Subject(s)
Gene Expression Regulation , Histone-Lysine N-Methyltransferase/chemistry , Histones/chemistry , Neoplasm Proteins/metabolism , Transcription, Genetic , Binding Sites , Cell Cycle , Chromatin/chemistry , Chromatin/metabolism , Chromosomal Proteins, Non-Histone , Humans , K562 Cells , Lysine/chemistry , Methylation , Protein Binding , Repressor Proteins , Tumor Suppressor Proteins
11.
Am J Transplant ; 6(10): 2502-5, 2006 Oct.
Article in English | MEDLINE | ID: mdl-16970800

ABSTRACT

Pancreatic panniculitis is an uncommon condition that can occur in association with pancreatic disease. We present a case of pancreatic panniculitis in a female pancreas-kidney transplant recipient 5 months post-transplant. The patient was on standard immunosuppressive medications and had acute rejection of her renal allograft. The diagnosis of allograft pancreatitis and rejection presenting with pancreatic panniculitis was supported clinically, histopathologically and by laboratory and imaging data. This is the fourth case of pancreatic panniculitis occurring in a transplant recipient and the first in a simultaneous pancreas-kidney transplant recipient. It is also the first case associated with allograft rejection. Clinicians should be aware that pancreatic panniculitis may be a manifestation of underlying allograft pancreatic disease.


Subject(s)
Graft Rejection/complications , Kidney Transplantation/adverse effects , Pancreas Transplantation/adverse effects , Pancreatitis/complications , Panniculitis, Nodular Nonsuppurative/etiology , Biopsy , Diabetes Mellitus, Type 1/complications , Diabetes Mellitus, Type 1/surgery , Diagnosis, Differential , Female , Follow-Up Studies , Graft Rejection/pathology , Humans , Kidney Failure, Chronic/complications , Kidney Failure, Chronic/surgery , Middle Aged , Pancreatitis/diagnosis , Panniculitis, Nodular Nonsuppurative/diagnosis
12.
Am J Transplant ; 6(10): 2375-83, 2006 Oct.
Article in English | MEDLINE | ID: mdl-16869795

ABSTRACT

Urinary tract infections are the most common infection in renal transplant patients and Escherichia coli (E. coli) is the most common clinical isolate. Although acute allograft injury (AAI) secondary to urinary tract infection (UTI) has been reported, the incidence of AAI associated with UTI, the virulence factors express by uropathic E. coli and whether virulence factors are associated with renal allograft outcome have not been described. We collected E. coli from our renal transplant patients with UTI, determined O:H serotypes, P and Dr fimbriae expression and the clinical presentation and allograft function during the UTI and post-UTI period. Pyelonephritis occurred in 40% of our patients, 82% of which had AAI (>20% increase in SCr). Sixty-two percent of E. coli isolates that expressed P fimbriae were associated with AAI, whereas only 29% that did not express P fimbriae had AAI (p = 0.03). The pattern of P fimbriae and O serotypes differed from reported isolates, as the P fimbriae PapG class II and the O25 serotype were the most common. Dr adhesin was expressed on 7 isolates, including 2 of 3 with urosepsis. We propose a unique pattern of uropathogenic serotypes and adherence factors contribute to acute allograft injury in renal transplant patients with UTI.


Subject(s)
Escherichia coli/pathogenicity , Kidney Transplantation , Urinary Tract Infections/microbiology , Adult , Antibodies, Bacterial/analysis , DNA, Bacterial/analysis , Escherichia coli/genetics , Escherichia coli/immunology , Female , Graft Survival , Humans , Male , Polymerase Chain Reaction , Postoperative Complications , Prognosis , Pyelonephritis/etiology , Pyelonephritis/microbiology , Transplantation, Homologous , Urinary Tract Infections/complications , Virulence
13.
J Postgrad Med ; 49(1): 69-71, 2003.
Article in English | MEDLINE | ID: mdl-12865574

ABSTRACT

Post-transplant lymphoproliferative disorder is treated with rapid decrement of immunosuppressive therapy. This cannot be achieved with ease in patients on long-term glucocorticoid therapy, as chronically suppressed adrenal glands may not be capable of mounting adequate response to stress. A 52-year-old Caucasian male presented with fever, orthostatic hypotension, lymphadenopathy and hyponatraemia. Serum cortisol levels were within normal levels with a sub optimal response to stimulation by ACTH. Hyponatraemia and orthostasis responded poorly to fluid restriction, saline and salt repletion but corrected after increasing the steroid dose. The normal baseline cortisol levels represented a stimulated adrenal gland, however, the ACTH stimulation had inadequate response. This sub optimal stimulation and a good response to increased steroids suggest the presence of relative or occult adrenal insufficiency. Relative adrenal insufficiency must be considered in patients who have received prolonged glucocorticoid therapy and have symptoms such as hypotension and/or hyponatraemia.


Subject(s)
Adrenal Insufficiency/etiology , Kidney Transplantation/adverse effects , Lymphoproliferative Disorders/complications , Lymphoproliferative Disorders/etiology , Adrenal Insufficiency/drug therapy , Adrenocorticotropic Hormone , Anti-Inflammatory Agents/therapeutic use , Glucocorticoids/pharmacology , Humans , Hyponatremia/etiology , Hypotension, Orthostatic/etiology , Immunosuppressive Agents/pharmacology , Kidney Transplantation/immunology , Male , Middle Aged , Prednisone/therapeutic use
14.
Eye (Lond) ; 17(4): 478-81, 2003 May.
Article in English | MEDLINE | ID: mdl-12802346

ABSTRACT

AIMS: The aim of this study was to compare the accuracy of incisional and punch biopsy techniques in obtaining correct histological diagnosis of periorbital eyelid tumours. The technique of punch biopsy is presented and described in detail. METHODS: A retrospective analysis was made of 20 consecutive incisional biopsies and 20 consecutive punch biopsies. In each case, the histology obtained at biopsy was compared with that identified at the time of tumour excision. RESULTS: A total of 40 consecutive biopsies on 38 patients were analysed. The first 20 were incisional; the second 20 were punch biopsies. Of the 20 incisional biopsy specimens, 19 were confirmed accurate at the time of excision of the lesion. Of the 20 punch biopsies, 17 were confirmed accurate at the time of excision. These correspond to accuracy rates of 95 and 85%, respectively. CONCLUSIONS: Both incisional and punch biopsy techniques have relatively high accuracy rates and there is a high concordance between tissue diagnoses made by each of these techniques. Incisional techniques should preferably be performed on any atypical lesion. Punch biopsy is a quick and simple procedure. It is easy to perform in an outpatient environment and requires a minimum of surgical equipment and no specific surgical skills. If the site of biopsy is carefully chosen, this simple technique provides tissue specimens of adequate size and quality for accurate histology and is a most useful adjunct in the management of periocular tumours.


Subject(s)
Carcinoma, Basal Cell/pathology , Carcinoma, Squamous Cell/pathology , Eyelid Neoplasms/pathology , Biopsy/instrumentation , Biopsy/methods , Humans , Retrospective Studies
16.
Curr Opin Cell Biol ; 13(3): 263-73, 2001 Jun.
Article in English | MEDLINE | ID: mdl-11343896

ABSTRACT

Post-translational addition of methyl groups to the amino-terminal tails of histone proteins was discovered more than three decades ago. Only now, however, is the biological significance of lysine and arginine methylation of histone tails being elucidated. Recent findings indicate that methylation of certain core histones is catalyzed by a family of conserved proteins known as the histone methyltransferases (HMTs). New evidence suggests that site-specific methylation, catalyzed by HMTs, is associated with various biological processes ranging from transcriptional regulation to epigenetic silencing via heterochromatin assembly. Taken together, these new findings suggest that histone methylation may provide a stable genomic imprint that may serve to regulate gene expression as well as other epigenetic phenomena.


Subject(s)
Gene Expression Regulation, Developmental/genetics , Heterochromatin/genetics , Histone-Lysine N-Methyltransferase , Histones/genetics , Lysine/metabolism , Methyltransferases/genetics , Acetylation , Animals , Chromobox Protein Homolog 5 , Chromosomal Proteins, Non-Histone/metabolism , DNA Methylation , Gene Expression Regulation, Developmental/physiology , Gene Silencing/physiology , Heterochromatin/metabolism , Histone Methyltransferases , Histones/metabolism , Humans , Lysine/genetics , Methylation , Methyltransferases/metabolism , Neoplasms/genetics , Neoplasms/metabolism , Protein Methyltransferases , Transcription, Genetic/genetics , Transcription, Genetic/physiology
17.
Science ; 292(5514): 110-3, 2001 Apr 06.
Article in English | MEDLINE | ID: mdl-11283354

ABSTRACT

The assembly of higher order chromatin structures has been linked to the covalent modifications of histone tails. We provide in vivo evidence that lysine 9 of histone H3 (H3 Lys9) is preferentially methylated by the Clr4 protein at heterochromatin-associated regions in fission yeast. Both the conserved chromo- and SET domains of Clr4 are required for H3 Lys9 methylation in vivo. Localization of Swi6, a homolog of Drosophila HP1, to heterochomatic regions is dependent on H3 Lys9 methylation. Moreover, an H3-specific deacetylase Clr3 and a beta-propeller domain protein Rik1 are required for H3 Lys9 methylation by Clr4 and Swi6 localization. These data define a conserved pathway wherein sequential histone modifications establish a "histone code" essential for the epigenetic inheritance of heterochromatin assembly.


Subject(s)
Cell Cycle Proteins/metabolism , Chromosomes, Fungal/metabolism , Heterochromatin/metabolism , Histone-Lysine N-Methyltransferase , Histones/chemistry , Histones/metabolism , Lysine/metabolism , Saccharomyces cerevisiae Proteins , Schizosaccharomyces pombe Proteins , Schizosaccharomyces/metabolism , Acetylation , Cell Cycle Proteins/chemistry , Cell Cycle Proteins/genetics , Centromere/metabolism , Fungal Proteins/genetics , Fungal Proteins/metabolism , Gene Silencing , Genes, Fungal , Histone Deacetylases/genetics , Histone Deacetylases/metabolism , Histone Methyltransferases , Methylation , Methyltransferases/chemistry , Methyltransferases/genetics , Methyltransferases/metabolism , Mutation , Protein Methyltransferases , Protein Structure, Tertiary , Recombinant Proteins/chemistry , Recombinant Proteins/metabolism , Schizosaccharomyces/genetics , Transcription Factors/metabolism
18.
J Ocul Pharmacol Ther ; 16(5): 429-38, 2000 Oct.
Article in English | MEDLINE | ID: mdl-11110034

ABSTRACT

In the present study, we examined the effect of inhibition of catalase with 3-aminotriazole (3-AT) on hydrogen peroxide (H2O2)-induced enhancement of sympathetic neurotransmission in bovine irides and on the inhibitory effect of this oxidant on norepinephrine (NE) release from human irides, in vitro. Furthermore, we investigated the effect of 3-AT on H2O2-induced attenuation of contractile responses to carbachol in the bovine isolated irides. Isolated mammalian irides were prepared for studies of [3H]NE release using the superfusion method and for contractile studies using isolated organ baths. At concentrations less than 100 microM, H2O2 had no significant effect on field-stimulated [3H]NE release from bovine or human irides. In bovine irides, 3-AT caused significant (P < 0.001) leftward shifts of concentration-response curves to H2O2 (10-300 microM). 3-AT also increased H2O2-induced attenuation of evoked [3H]NE release from human isolated irides. Low concentrations of H2O2 (< 100 microM) had no effect on carbachol contractions. However, 3-AT unmasked an inhibitory effect of low concentrations of H2O2 (3-100 microM) on carbachol-induced contractions. We conclude that inhibition of catalase causes both pre- and postjunctional responses of isolated mammalian irides to be more susceptible to oxidative stress induced by H2O2.


Subject(s)
Catalase/physiology , Hydrogen Peroxide/toxicity , Iris/drug effects , Amitrole/pharmacology , Animals , Carbachol/pharmacology , Catalase/antagonists & inhibitors , Cattle , Female , In Vitro Techniques , Iris/physiology , Muscle Contraction/drug effects , Norepinephrine/metabolism , Oxidative Stress
19.
Carcinogenesis ; 21(9): 1761-5, 2000 Sep.
Article in English | MEDLINE | ID: mdl-10964110

ABSTRACT

Functional inactivation of BRCA1 is an important mechanism involved in breast cancer pathogenesis. Mutation is often responsible for BRCA1 inactivation in familial breast cancer, but is not responsible for the decreased levels of BRCA1 seen in a subset of sporadic breast cancer patients. To determine if aberrant cytosine methylation of the BRCA1 promoter is associated with decreased BRCA1 gene expression in human breast cancer, high resolution bisulfite sequence analysis was used to analyze the cytosine methylation status of the BRCA1 promoter in 21 axillary node negative breast cancer patients with known levels of BRCA1 expression. Aberrant cytosine methylation of the BRCA1 promoter was detected in three of 21 patient specimens. These three specimens also expressed the lowest levels of BRCA1. Results from this analysis show that aberrant cytosine methylation of the BRCA1 promoter is directly correlated with decreased levels of BRCA1 expression in human breast cancer, and suggest that epigenetic silencing may be one mechanism of transcriptional inactivation of BRCA1 in sporadic mammary carcinogenesis.


Subject(s)
Breast Neoplasms/genetics , DNA Methylation , Genes, BRCA1/genetics , RNA, Messenger/metabolism , BRCA1 Protein/biosynthesis , BRCA1 Protein/genetics , Breast Neoplasms/metabolism , CpG Islands , Cytosine/metabolism , DNA, Neoplasm/genetics , DNA, Neoplasm/metabolism , Female , Gene Expression Regulation, Neoplastic/physiology , Gene Silencing/physiology , Humans , Promoter Regions, Genetic/physiology , RNA, Messenger/genetics
20.
Nucleic Acids Res ; 28(17): 3233-9, 2000 Sep 01.
Article in English | MEDLINE | ID: mdl-10954590

ABSTRACT

BRCA1 expression is repressed by aberrant cytosine methylation in sporadic breast cancer. We hypothesized that aberrant cytosine methylation of the BRCA1 promoter was associated with the transcriptionally repressive effects of histone hypoacetylation and chromatin condensation. To address this question, we developed an in vitro model of study using normal cells and sporadic breast cancer cells with known levels of BRCA1 transcript to produce a 1.4 kb 5-methylcytosine map of the BRCA1 5' CpG island. While all cell types were densely methylated upstream of -728 relative to BRCA1 transcription start, all normal and BRCA1 expressing cells were non-methylated downstream of -728 suggesting that this region contains the functional BRCA1 5' regulatory region. In contrast, the non-BRCA1 expressing UACC3199 cells were completely methylated at all 75 CpGs. Chromatin immunoprecipitations showed that the UACC3199 cells were hypoacetylated at both histones H3 and H4 in the BRCA1 promoter compared to non-methylated BRCA1 expressing cells. The chromatin of the methylated UACC3199 BRCA1 promoter was inaccessible to DNA-protein interactions. These data indicate that the epigenetic effects of aberrant cytosine methylation, histone hypoacetylation and chromatin condensation act together in a discrete region of the BRCA1 5' CpG island to repress BRCA1 transcription in sporadic breast cancer.


Subject(s)
Chromatin/metabolism , Cytosine/analogs & derivatives , Cytosine/metabolism , DNA Methylation , Gene Silencing , Genes, BRCA1/genetics , Histones/metabolism , Promoter Regions, Genetic/genetics , 5-Methylcytosine , Acetylation , Breast/cytology , Breast/metabolism , Breast/pathology , Breast Neoplasms/genetics , Cell Line , Chromatin/chemistry , Chromatin/genetics , CpG Islands/genetics , Female , Gene Expression Regulation, Neoplastic , Histones/chemistry , Humans , Precipitin Tests , Transcription, Genetic/genetics , Tumor Cells, Cultured
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