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1.
Br J Dermatol ; 178(3): 749-760, 2018 03.
Article in English | MEDLINE | ID: mdl-28815554

ABSTRACT

BACKGROUND: Striae gravidarum (SG), or stretch marks of pregnancy, begin as erythematous streaks and mature into hypopigmented atrophic bands. OBJECTIVES: In order to investigate molecular alterations that may promote atrophy of SG, we investigated dermal type I collagen fibrils, which provide human skin with support. METHODS: We obtained skin samples of recently developed, erythematous abdominal SG from pregnant women. To examine the organization of collagen fibrils, second-harmonic generation imaging was performed using multiphoton microscopy. Immunostaining was used to determine protein expression and localization of type I procollagen, the precursor of type I collagen fibrils. Real-time polymerase chain reaction was used to determine gene expression levels. RESULTS: In control (hip) and stretched normal-appearing perilesional abdominal skin, dermal collagen fibrils were organized as tightly packed, interwoven bundles. In SG, collagen bundles appeared markedly separated, especially in the mid-to-deep dermis. In the spaces separating these bundles, loosely packed wavy collagen fibrils lacking organization as bundles were present. These disorganized fibrils persisted into the postpartum period and failed to form densely packed bundles. Numerous large fibroblasts displaying type I procollagen expression were in close proximity to the disorganized fibrils, suggesting that the fibrils are newly synthesized. Supporting this possibility, immunostaining and gene expression of type I procollagen were increased throughout the dermis of SG. CONCLUSIONS: Early SG display marked separation of collagen bundles and emergence of disorganized collagen fibrils that fail to form bundles. These alterations may reflect ineffective repair of collagen bundles disrupted by intense skin stretching. Persistent disruption of the collagenous extracellular matrix likely promotes formation and atrophy of SG.


Subject(s)
Collagen Diseases/pathology , Pregnancy Complications/pathology , Striae Distensae/pathology , Case-Control Studies , Collagen Diseases/metabolism , Collagen Type I/metabolism , Female , Fibrillar Collagens/physiology , Fibroblasts/metabolism , Humans , Pregnancy , Pregnancy Complications/metabolism , Procollagen/biosynthesis , Skin/blood supply , Striae Distensae/metabolism , Young Adult
2.
Ann Oncol ; 28(6): 1316-1324, 2017 Jun 01.
Article in English | MEDLINE | ID: mdl-29177434

ABSTRACT

BACKGROUND: Approximately 5%-10% of gastric cancers have a fibroblast growth factor receptor-2 (FGFR2) gene amplification. AZD4547 is a selective FGFR-1, 2, 3 tyrosine kinase inhibitor with potent preclinical activity in FGFR2 amplified gastric adenocarcinoma SNU16 and SGC083 xenograft models. The randomized phase II SHINE study (NCT01457846) investigated whether AZD4547 improves clinical outcome versus paclitaxel as second-line treatment in patients with advanced gastric adenocarcinoma displaying FGFR2 polysomy or gene amplification detected by fluorescence in situ hybridization. PATIENTS AND METHODS: Patients were randomized 3:2 (FGFR2 gene amplification) or 1:1 (FGFR2 polysomy) to AZD4547 or paclitaxel. Patients received AZD4547 80 mg twice daily, orally, on a 2 weeks on/1 week off schedule of a 21-day cycle or intravenous paclitaxel 80 mg/m2 administered weekly on days 1, 8, and 15 of a 28-day cycle. The primary end point was progression-free survival (PFS). Safety outcomes were assessed and an exploratory biomarker analysis was undertaken. RESULTS: Of 71 patients randomized (AZD4547 n = 41, paclitaxel n = 30), 67 received study treatment (AZD4547 n = 40, paclitaxel n = 27). Among all randomized patients, median PFS was 1.8 months with AZD4547 and 3.5 months with paclitaxel (one-sided P = 0.9581); median follow-up duration for PFS was 1.77 and 2.12 months, respectively. The incidence of adverse events was similar in both treatment arms. Exploratory biomarker analyses revealed marked intratumor heterogeneity of FGFR2 amplification and poor concordance between amplification/polysomy and FGFR2 mRNA expression. CONCLUSIONS: AZD4547 did not significantly improve PFS versus paclitaxel in gastric cancer FGFR2 amplification/polysomy patients. Considerable intratumor heterogeneity for FGFR2 gene amplification and poor concordance between FGFR2 amplification/polysomy and FGFR2 expression indicates the need for alternative predictive biomarker testing. AZD4547 was generally well tolerated.


Subject(s)
Adenocarcinoma/drug therapy , Antineoplastic Agents/administration & dosage , Benzamides/administration & dosage , Paclitaxel/administration & dosage , Piperazines/administration & dosage , Pyrazoles/administration & dosage , Receptor, Fibroblast Growth Factor, Type 2/genetics , Stomach Neoplasms/drug therapy , Adenocarcinoma/genetics , Antineoplastic Agents/adverse effects , Benzamides/adverse effects , Cell Line, Tumor , Disease-Free Survival , Gene Amplification , Humans , Paclitaxel/adverse effects , Piperazines/adverse effects , Pyrazoles/adverse effects , Stomach Neoplasms/genetics
3.
Soc Sci Med ; 177: 27-34, 2017 03.
Article in English | MEDLINE | ID: mdl-28157566

ABSTRACT

Housing is a significant determinant of health and substandard housing is a public health issue. East London has long had a shortage of social and affordable housing, worsened in recent years by a combination of stressors. In one of East London's most deprived boroughs, Newham, changes brought about by the 2011 Localism Act and the unique demands of being the host Olympic borough in 2012 have brought considerable pressures to bear on social infrastructure. This paper examines how these pressures were experienced by local residents via their narratives of social housing and health. The data reported here are from a qualitative study comprising two waves of data collection. Narrative family interviews and go-along interviews were conducted with 40 Newham residents at wave one and 28 at wave two. A narrative analysis with a Bakhtinian interpretation was undertaken. This revealed that residents framed experiences of social housing in terms of an inherent system-level ideology based on notions of need and waiting. A particularly striking feature of this ideology was the extent to which descriptions of ill health and impairment were implicated in constructions of housing need; participants directly attributed a range of health complaints to their housing predicaments, including stress, depression, cancer scares, panic attacks and loss of sleep. Understanding the contested ideology of social housing can illuminate both the dynamic processes of social exclusion and the ways in which its subjects seek to resist it.


Subject(s)
Health Status , Housing/trends , Narration , Perception , Adult , Female , Humans , Income/trends , London/ethnology , Male , Middle Aged , Qualitative Research , Racial Groups/psychology , Racial Groups/statistics & numerical data , Sex Factors , Sociological Factors
4.
Health Place ; 36: 18-24, 2015 Nov.
Article in English | MEDLINE | ID: mdl-26340644

ABSTRACT

Mega-sporting event regeneration, as a specific approach to urban renewal, uses impending host-city status as a catalyst for revitalisation and has the potential to improve health both through addressing deprivation and by promoting increased sport and physical activity among the host-city's population. This qualitative study explored how hosting of the London 2012 Games impacted upon the way East London residents perceived and experienced the social determinants of health in their local neighbourhood. We conducted narrative family interviews, go-along interviews and video focus group workshops with 66 Newham residents, aged 12-55 years, immediately after the Games. A narrative analytic approach examined accounts of health and wellbeing experiences in terms of neighbourhood change and the spectacle of the Games. Participants of this qualitative study generally welcomed the respite and the unexpected chance to live in a cleaner, safer and more unified environment. However, this positivity was underscored by an acute awareness that this was a very temporary situation and one that was intended to support the event rather than residents.


Subject(s)
Anniversaries and Special Events , Social Determinants of Health , Sports , Urban Renewal , Adult , Female , Humans , Interviews as Topic , London , Male , Middle Aged , Qualitative Research , Young Adult
5.
Br J Dermatol ; 173(6): 1420-30, 2015 Dec.
Article in English | MEDLINE | ID: mdl-26179468

ABSTRACT

BACKGROUND: Striae gravidarum (SG), or 'stretch marks' of pregnancy, begin as erythematous streaks, and mature over months to years to become permanent scar-like bands that may be hypopigmented, atrophic and lax. OBJECTIVES: To investigate early molecular alterations that may promote laxity of mature SG, we investigated the dermal elastic fibre network, which provides human skin with elastic properties. METHODS: We obtained skin samples of newly developed, erythematous abdominal SG in healthy pregnant women. The elastic fibre network was examined by Verhoeff elastic staining and immunofluorescence staining of skin sections. Gene expression was measured by real-time polymerase chain reaction. RESULTS: The normal elastic fibre network appeared markedly disrupted in SG, compared with perilesional abdominal skin or control (normal-appearing hip skin). This disruption was accompanied by the emergence of short, disorganized, thin, thread-like 'fibrils', which were observed prominently in the mid-to-deep dermis. These fibrils were rich in tropoelastin (the main component of normal elastic fibres), and persisted into the postpartum period without forming normal-appearing elastic fibres. The emergence of these fibrils was accompanied by increased gene expression of tropoelastin and fibrillin-1, but not other elastic fibre components, including fibrillin-2 and fibulin-1, -2 or -5. CONCLUSIONS: In early SG, the elastic fibre network appears markedly disrupted, and newly synthesized tropoelastin-rich fibrils emerge, likely as a result of uncoordinated synthesis of elastic fibre components. Because they are thin and disorganized, tropoelastin-rich fibrils likely do not function as normal elastic fibres do. These observations provide the foundations for elucidating pathogenic mechanisms by which laxity may develop in SG.


Subject(s)
Elastic Tissue/pathology , Striae Distensae/pathology , Collagen Diseases/pathology , Elastic Tissue/metabolism , Female , Humans , Pregnancy , Puerperal Disorders/metabolism , Puerperal Disorders/pathology , Striae Distensae/metabolism , Tropoelastin/metabolism , Young Adult
6.
Oncogene ; 32(37): 4406-16, 2013 Sep 12.
Article in English | MEDLINE | ID: mdl-23108397

ABSTRACT

αvß6 integrin expression is upregulated on a wide range of epithelial tumours, and is thought to play a role in modulating tumour growth. Here we describe a human therapeutic antibody 264RAD, which binds and inhibits αvß6 integrin function. 264RAD cross-reacts with human, mouse and cynomolgus monkey αvß6, and inhibits binding to all ligands including the latency-associated peptide of TGF-ß. Screening across a range of integrins revealed that 264RAD also binds and inhibits the related integrin αvß8, but not the integrins α5ß1, αvß3, αvß5 and α4ß1. In vitro 264RAD inhibited invasion of VB6 and Detroit 562 cells in a Matrigel invasion assay and αvß6 mediated production of matrix metalloproteinase-9 in Calu-3 cells. It inhibited TGF-ß-mediated activation of dermal skin fibroblasts by preventing local activation of TGF-ß by NCI-H358 tumour cells in a tumour cell-fibroblast co-culture assay. In vivo 264RAD showed dose-dependent inhibition of Detroit 562 tumour growth, regressing established tumours when dosed at 20 mg/kg once weekly. The reduction in growth associated with 264RAD was related to a dose-dependent inhibition of Ki67 and phospho-ERK and a reduction of αvß6 expression in the tumour cells, coupled to a reduction in fibronectin and alpha smooth muscle actin expression in stromal fibroblasts. 264RAD also reduced the growth and metastasis of orthotopic 4T1 tumours. At 20 mg/kg growth of both the primary tumour and the number of metastatic deposits in lung were reduced. The data support the conclusion that 264RAD is a potent inhibitor of αvß6 integrin, with some activity against αvß8 integrin, that reduces both tumour growth and metastasis.


Subject(s)
Antibodies, Monoclonal, Humanized/pharmacology , Integrins/antagonists & inhibitors , Animals , Antibodies, Monoclonal, Humanized/immunology , Antibodies, Monoclonal, Humanized/metabolism , Antigens, Neoplasm/immunology , Antigens, Neoplasm/metabolism , Biomarkers/metabolism , Cell Line , Cell Movement/drug effects , Cell Proliferation/drug effects , Coculture Techniques , Female , Humans , Integrins/immunology , Integrins/metabolism , Lung Neoplasms/drug therapy , Lung Neoplasms/metabolism , Lung Neoplasms/secondary , Macaca fascicularis , Matrix Metalloproteinase 9/biosynthesis , Mice , Neoplasms/metabolism , Neoplasms/pathology , Protein Binding , Transforming Growth Factor beta/metabolism , Xenograft Model Antitumor Assays
7.
Am J Transplant ; 10(11): 2421-30, 2010 Nov.
Article in English | MEDLINE | ID: mdl-20977633

ABSTRACT

Ischemia/reperfusion injury and delayed graft function (DGF) following organ transplantation adversely affect graft function and survival. A large animal model has not been characterized. We developed a pig kidney allograft model of DGF and evaluated the cytoprotective effects of inhaled carbon monoxide (CO). We demonstrate that donor warm ischemia time is a critical determinant of DGF as evidenced by a transient (4-6 days) increase in serum creatinine and blood urea nitrogen following transplantation before returning to baseline. CO administered to recipients intraoperatively for 1 h restored kidney function more rapidly versus air-treated controls. CO reduced acute tubular necrosis, apoptosis, tissue factor expression and P-selectin expression and enhanced proliferative repair as measured by phosphorylation of retinol binding protein and histone H3. Gene microarray analyses with confirmatory PCR of biopsy specimens showed that CO blocked proinflammatory gene expression of MCP-1 and heat shock proteins. In vitro in pig renal epithelial cells, CO blocks anoxia-reoxygenation-induced cell death while promoting proliferation. This large animal model of DGF can be utilized for testing therapeutic strategies to reduce or prevent DGF in humans. The efficacy of CO on improving graft function posttransplant validates the model and offers a potentially important therapeutic strategy to improve transplant outcomes.


Subject(s)
Carbon Monoxide/therapeutic use , Delayed Graft Function/drug therapy , Kidney Transplantation/physiology , Animals , Carbon Monoxide/pharmacokinetics , Cell Death/drug effects , Cell Proliferation/drug effects , Female , Gene Expression Profiling , Graft Rejection/prevention & control , Kidney/metabolism , Kidney Tubular Necrosis, Acute/etiology , Kidney Tubular Necrosis, Acute/immunology , Reperfusion Injury/prevention & control , Swine , Tacrolimus/pharmacokinetics
8.
J Epidemiol Community Health ; 63(3): 253-8, 2009 Mar.
Article in English | MEDLINE | ID: mdl-19074925

ABSTRACT

BACKGROUND: Previous research strongly suggests that ethnic minority groups are more likely to suffer a poorer health profile compared with the overall population, although it is not clear whether these inequalities persist over generations. This study aimed to establish the degree to which ethnic inequalities in health are transmitted from the first to the second generation, and to determine the extent to which intergenerational changes in socioeconomic status and health behaviours might explain any variation that exists. METHODS: Data from the 1999 and 2004 Health Surveys for England assessed the prevalence of fair/poor general health across first (n = 4492) and second (n = 5729) generations of six ethnic minority populations. A white population was selected as reference (n = 18 407). The risk of fair/poor general health was estimated by applying logistic regression models and stepwise inclusion of demographic, socioeconomic and behavioural variables. Generational movement relative to the white baseline was assessed for all ethnic groups adjusted for age and sex. RESULTS: No significant differences in levels of reported fair/poor general health were observed between generations. After adjusting for improved socioeconomic position, the second generation became more likely to report worse health, whereas adjusting for differences in health behaviours had no effect. The Bangladeshi population showed significant intergenerational improvement in general health relative to the white reference, showing a reduction in the odds ratio (95% CI) from 2.75 (2.14 to 3.56) for the first generation to 1.58 (1.17 to 2.13) in the second generation. CONCLUSION: Ethnic minorities in England report consistent rates of fair/poor general health across generations, despite the health benefits resulting from upward social mobility. These health inequalities are unaffected by changes in health behaviours. Understanding these intergenerational pathways will have important public health policy implications as the migrant population not only ages, but also reproduces.


Subject(s)
Ethnicity/statistics & numerical data , Health Status Disparities , Minority Groups/statistics & numerical data , Adolescent , Adult , Aged , Aged, 80 and over , Educational Status , England , Family Health , Female , Health Behavior , Health Surveys , Humans , Male , Middle Aged , Social Class , Social Mobility/statistics & numerical data , Socioeconomic Factors , Young Adult
9.
J Orthod ; 34(3): 173-5, 2007 Sep.
Article in English | MEDLINE | ID: mdl-17761800

ABSTRACT

A method of controlled movement of teeth using open and closed coil spring. A 'clinical pearl' describing an original clinical technique to prevent uncontrolled tooth movement while using an active coil spring on the archwire.


Subject(s)
Orthodontic Wires , Tooth Movement Techniques/instrumentation , Dental Stress Analysis , Humans , Orthodontic Appliance Design
10.
Carcinogenesis ; 27(10): 2133-9, 2006 Oct.
Article in English | MEDLINE | ID: mdl-16782971

ABSTRACT

The Apc(Min/+) mouse model is a clinically relevant model of early intestinal cancer. We used AZD2171, an oral, highly potent and selective vascular endothelial growth factor (VEGF) signaling inhibitor, to investigate the role of VEGF receptor-2 (VEGFR-2) signaling in adenoma development and growth in Apc(Min/+) mice. AZD2171 (5 mg/kg body wt/day) was administered once daily for 28 days to 6-week-old (early-intervention) or 10-week-old (late intervention) mice. In the early-intervention study, AZD2171 reduced the number of macroscopic polyps in the small bowel and colon. Macropolyp diameter was lower in the small bowel, but remained unchanged in the colon. In animals receiving AZD2171, microscopic evaluation of the small intestine showed a significant reduction in the number of larger lesions. In the late-intervention study, AZD2171 treatment reduced macropolyp diameter (but not number) in the small intestine. Microscopic analysis revealed that AZD2171 significantly reduced the number of larger micropolyps in the small bowel, with no large micropolyps present in the colon. AZD2171 treatment had no effect on microvessel density or localization of beta-catenin staining in adenomas or non-tumor intestinal tissue, but significantly reduced the number of cells expressing VEGFR-2 mRNA. In conclusion, the effects of AZD2171 in the small intestine of Apc(Min/+) mice are consistent with an antiangiogenic mechanism of action, limiting growth of adenomas to < or =1 mm. These data also suggest that an early step in adenoma development may depend on VEGFR-2 signaling. Together, these results indicate that VEGFR-2 signaling may play key roles in the development and progression of intestinal adenomas.


Subject(s)
Adenoma/prevention & control , Genes, APC/physiology , Intestinal Neoplasms/prevention & control , Intestinal Polyps/drug therapy , Quinazolines/therapeutic use , Signal Transduction/drug effects , Vascular Endothelial Growth Factor Receptor-2/antagonists & inhibitors , Animals , Female , Male , Mice , Mice, Inbred C57BL , RNA, Messenger/analysis , Splenomegaly/prevention & control , Vascular Endothelial Growth Factor Receptor-2/genetics
12.
Connect Tissue Res ; 42(1): 59-69, 2001.
Article in English | MEDLINE | ID: mdl-11696989

ABSTRACT

Cartilage formation during embryonic development and in fracture healing in adult animals involves chondrogenic differentiation of mesenchymal precursors. Here we describe an in vitro model whereby human dermal fibroblasts, considered to be restricted to a fibroblast lineage, are apparently redirected toward a chondrogenic phenotype by high density micromass culture in the presence of lactic acid. Micromass cultures treated with 40 mM lactate exhibited increased levels of Alcian blue staining and sulfate incorporation, indicative of elevated sulfated glycosaminoglycan synthesis. Northern analysis revealed an up-regulation of chondroitin sulfate proteoglycan 1 (aggrecan) and transforming growth factor-beta 1 mRNA and a decrease in type I collagen expression. Type II collagen was detected by reverse transcription-PCR only in experimental cultures. Although the observed changes in biosynthesis and gene expression were consistent with differentiating chondrocytes, the cells displayed an elongated, fibroblast-like morphology. These findings suggest that dermal fibroblasts may be committed to differentiate along a chondrogenic pathway by in vitro culture under specific forcing conditions.


Subject(s)
Collagen Type II/genetics , Collagen Type I/genetics , Extracellular Matrix Proteins , Fibroblasts/drug effects , Gene Expression Regulation , Lactic Acid/pharmacology , Proteoglycans/genetics , Aggrecans , Cell Count , Cell Differentiation , Cells, Cultured , Dermis/cytology , Fibroblasts/cytology , Fibroblasts/metabolism , Gene Expression Profiling , Humans , Lectins, C-Type , Phenotype , Transforming Growth Factor beta/genetics , Transforming Growth Factor beta1
13.
J Morphol ; 246(3): 192-7, 2000 Dec.
Article in English | MEDLINE | ID: mdl-11077431

ABSTRACT

Ice worms occupy a unique position in metazoan phylogeny in that they are the only known annelid that completes its life cycle in ice. The mechanism(s) associated with this adaptation are likely to occur at different levels, ranging from modification of their metabolism to changes in morphology. In this study, we examined specimens of Mesenchytraeus solifugus by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) in an effort to identify morphologic structures that may aid in its glacial habitation. We report that M. solifugus contains an elongated head pore at the tip of its prostomium, numerous sensory structures, and differentially oriented setae that curve abruptly at their distal end.


Subject(s)
Annelida/ultrastructure , Alaska , Animals , Head , Ice , Sense Organs/ultrastructure
14.
FEBS Lett ; 468(2-3): 109-14, 2000 Feb 25.
Article in English | MEDLINE | ID: mdl-10692568

ABSTRACT

Pseudogenes are commonly encountered during investigation of the genomes of a wide range of life forms. This review concentrates on vertebrate, and in particular mammalian, pseudogenes and describes their origin and subsequent evolution. Consideration is also given to pseudogenes that are transcribed and to the unusual group of genes that exist at the interface between functional genes and non-functional pseudogenes. As the sequences of different genomes are characterised, the recognition and interpretation of pseudogene sequences will become more important and have a greater impact in the field of molecular genetics.


Subject(s)
Pseudogenes , Vertebrates/genetics , Animals , Evolution, Molecular , Genome, Human , Humans , Retroelements
16.
Nucleic Acids Res ; 25(17): 3552-4, 1997 Sep 01.
Article in English | MEDLINE | ID: mdl-9254719

ABSTRACT

A band extracted from a differential display polyacrylamide gel often represents a composite of heterogeneous products. We have developed a non- radioactive method to simply and rapidly analyse its complexity. A fluorescent restriction enzyme fingerprint of the composite mixture is generated. The number of individual bands observed in this fingerprint indicates the complexity of the re-amplified cDNA mixture. Restriction fingerprints of the inserts of cDNA subclones derived from the re-amplified cDNA mixture are compared to the composite fingerprint to select those representing the most intense bands in the composite. This dramatically reduces the number of clones required for further characterisation.


Subject(s)
DNA, Complementary/analysis , Electrophoresis, Polyacrylamide Gel , Polymerase Chain Reaction , RNA-Directed DNA Polymerase , Base Sequence , DNA Fingerprinting , DNA Restriction Enzymes , DNA, Complementary/chemistry , Fluoresceins , Fluorescent Dyes , Molecular Sequence Data
17.
Biotechniques ; 23(2): 274-9, 1997 Aug.
Article in English | MEDLINE | ID: mdl-9266082

ABSTRACT

We have modified the automated differential display reverse transcription polymerase chain reaction technique (DDRT-PCR) such that a single fluorescently labeled universal primer (d(F)CTCACG-GATCCGTCGATTTT) is used in all PCRs together with a selection of arbitrary primers. We term this fluorescent detection procedure FDDRT-PCR. Anchoring primers of general structure dTGGTCTCACGGATCCTCGA-(T)12 VN (where N can be any deoxynucleoside and V can be any deoxynucleoside other than thymidine) are used for the RT step, and the universal primer together with selected arbitrary primers are then used for the PCR amplification. Advantages of this approach are: (i) the fluorescently labeled universal primer is a constant feature in every PCR, so that changes in banding profile are highly likely to reflect the incorporation of different arbitrary 10-mer primers; (ii) artifacts that result from arbitrary 10-mer to arbitrary 10-mer primer amplifications are not observed by fluoresence detection on an automated gene scanner because such products are not fluorescently labeled; (iii) sample throughput and ease of data handling are increased when compared with the conventional radioactive/manual approach and (iv) using a single fluorescently labeled primer in all PCRs is highly cost-effective.


Subject(s)
DNA Primers , Fluorescent Dyes , Polymerase Chain Reaction/methods , Sequence Analysis, DNA/methods , Autoradiography , Base Sequence , DNA, Complementary/analysis , Polymerase Chain Reaction/standards
18.
Hum Mol Genet ; 6(2): 285-9, 1997 Feb.
Article in English | MEDLINE | ID: mdl-9063749

ABSTRACT

Most multiple case families of young onset breast cancer and ovarian cancer are thought to be due to highly penetrant mutations in the predisposing genes BRCA1 and BRCA2. However, these mutations are uncommon in the population and they probably account for only a few percent of all breast cancer incidence. A much larger fraction of breast cancer might, in principle, be due to common variants which confer more modest individual risks. There are several common polymorphisms in the BRCA1 gene which generate amino acid substitutions. We have examined the frequency of four of these polymorphisms: Gln356Arg, Pro871Leu, Glu1038Gly and Ser1613Gly in large series of breast and ovarian cancer cases and matched controls. Due to strong linkage disequilibrium, these four sites generate only three haplotypes with a frequency > 1.3%. The most common haplotypes, defined by the alleles Gln356Pro871Glu1038Ser1613 and Gln356Leu871Gly1038Gly1613, have frequencies of 0.57 and 0.32 respectively, and these frequencies do not differ significantly between patient and control groups. Thus the most common polymorphisms of the BRCA1 gene do not make a significant contribution to breast or ovarian cancer risk. However, our data suggest that the Arg356 allele may have a different genotype distribution in breast cancer patients from that in controls (Arg356 homozygotes are more frequent in the control groups, P = 0.01), indicating that it may be protective against breast cancer. If this finding can be confirmed, it may provide an insight into the structural features of the BRCA1 protein that are important for its function.


Subject(s)
BRCA1 Protein/genetics , Breast Neoplasms/genetics , Genetic Variation , Ovarian Neoplasms/genetics , Adult , Aged , Alleles , Case-Control Studies , Cohort Studies , Female , Genetic Predisposition to Disease , Genotype , Humans , Middle Aged
19.
Biol Trace Elem Res ; 52(3): 209-25, 1996 Jun.
Article in English | MEDLINE | ID: mdl-8811279

ABSTRACT

The bioavailability of selenium (Se) was determined in bacterial strains that reduce selenite to red elemental Se (SeO). A laboratory strain of Bacillus subtilis and a bacterial rod isolated from soil in the vicinity of the Kesterson Reservoir, San Joaquin Valley, CA, (Microbacterium arborescens) were cultured in the presence of 1 mM sodium selenite (Na2SeO3). After harvest, the washed, lyophilized B. Subtilis and M. arborescens samples contained 2.62 and 4.23% total Se, respectively, which was shown to consist, within error, entirely of SeO. These preparations were fed to chicks as supplements to a low-Se, vitamin E-free diet. Three experiments showed that the Se in both bacteria had bioavailabilities of approx 2% that of selenite. A fourth experiment revealed that gray SeO had a bioavailability of 2% of selenite, but that the bioavailability of red SeO depended on the way it was prepared (by reduction of selenite). When glutathione was the reductant, bioavailability resembled that of gray SeO and bacterial Se; when ascorbate was the reductant, bioavailability was twice that level (3-4%). These findings suggest that aerobic bacteria such as B. subtilis and M. arborescens may be useful for the bioremediation of Se-contaminated sites, i.e., by converting selenite to a form of Se with very low bioavailability.


Subject(s)
Selenium/blood , Sodium Selenite/metabolism , Animals , Bacillus subtilis/metabolism , Biological Availability , Chickens , Culture Media , Glutathione Peroxidase/metabolism , Glutathione Reductase/chemistry , Hydrolysis , Male , Microscopy, Electron, Scanning , Oxidation-Reduction , Selenium/pharmacokinetics , Sodium Selenite/chemistry , Soil Microbiology , Spectrophotometry, Atomic , Vitamin E Deficiency
20.
Biofactors ; 5(1): 29-37, 1995 May.
Article in English | MEDLINE | ID: mdl-7546216

ABSTRACT

We have demonstrated that the common soil bacterium, Bacillus subtilis, reduces selenite to an insoluble and much less toxic product--the red form of elemental selenium. Reduction was effected by an inducible system that appears to deposit elemental selenium between the cell wall and the plasma membrane. Glucose and sucrose supported selenite reduction. Although malate and citrate supported growth, no significant reduction of selenite occurred, indicating the importance of the redox state of the culture substrate. Selenite reduction in the millimolar concentration range (i.e., cultures supplemented with 1 mM selenite) was not affected by a ten-fold excess of nitrate or sulfate--compounds that serve as alternate electron acceptors and antagonize selenite reduction by anaerobic bacteria. Similarly, nitrite and sulfite did not significantly affect the rate or extent of selenite reduction. B.subtilis was able to grow and produce selenium (Se degree) at selenite concentrations ranging from 0.6 microM to 5 mM (50 ppb to 395 ppm selenium). At the lowest selenite concentration tested, 50 ppb selenium, B.subtilis removed 95% of the selenite from the liquid phase. The results suggest that selenite is reduced via an inducible detoxification system rather than dissimilatory electron transport. The findings establish the potential utility of B.subtilis for the bioremediation of selenite-polluted sites.


Subject(s)
Bacillus subtilis/metabolism , Selenium/metabolism , Sodium Selenite/metabolism , Bacillus subtilis/growth & development , Cell Membrane/metabolism , Cell Wall/metabolism , Citrates/pharmacology , Citric Acid , Culture Media , Glucose/pharmacology , Malates/pharmacology , Nitrates/pharmacology , Oxidation-Reduction , Sucrose/pharmacology , Sulfates/pharmacology
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