Search filters

List of works by Berthold Huppertz

3-dimensional colour power angiography for staging human placental development

scientific article published in The Lancet

A comparative study of five physiological key parameters between four different human trophoblast-derived cell lines

scientific article

A comparative study of the effect of three different syncytiotrophoblast micro-particles preparations on endothelial cells

scientific article published in January 2005

A possible protective role of Nrf2 in preeclampsia

scientific article

A role for GPR55 in human placental venous endothelial cells

scientific article published on 14 April 2015

A role for Nrf2 in redox signalling of the invasive extravillous trophoblast in severe early onset IUGR associated with preeclampsia

scientific article

A variety of opportunities for immune interactions during trophoblast development and invasion.

scientific article published on May 2012

Aberrations of early trophoblast differentiation predispose to pregnancy failure: lessons from the anti-phospholipid syndrome

scientific article

Adverse effects of lupus anticoagulant positive blood sera on placental viability can be prevented by heparin in vitro

scientific article published in December 2004

Altered protease expression by periarterial trophoblast cells in severe early-onset preeclampsia with IUGR

scientific article published in January 2006

Amnion-Derived Mesenchymal Stromal Cells Show Angiogenic Properties but Resist Differentiation into Mature Endothelial Cells

scientific article published on 20 May 2012

Amnion-derived mesenchymal stromal cells show a mesenchymal-epithelial phenotype in culture

scientific article published on 11 December 2013

An improved and rapid method to construct skin equivalents from human hair follicles and fibroblasts

scientific article published in August 2001

An integrative view on the physiology of human early placental villi

scientific article published on December 2013

An updated view on the origin and use of angiogenic biomarkers for preeclampsia

scientific article published on 14 November 2018

Anti-adhesive glycosylation of fibronectin-like molecules in human placental matrix-type fibrinoid.

scientific article published in October 1995

Apoptosis and its role in the trophoblast

scientific article published on 31 March 2006

Apoptosis in the trophoblast--role of apoptosis in placental morphogenesis

scientific article published in September 2004

Apoptosis: Molecular Control of Placental Function—A Workshop Report

scientific article published in April 2001

Apoptotic death ligands and interleukins in the vitreous of diabetic patients

scientific article published in December 2010

Are morphological criteria sufficient for the identification of circulating tumor cells in renal cancer?

scientific article published on 17 September 2013

Arterial endothelial cytokines guide extravillous trophoblast invasion towards spiral arteries; an in-vitro study with the trophoblast cell line ACH-3P and female non-uterine endothelial cells

scientific article published on 19 December 2015

Author's reply to commentary by Hennig Stieve

scientific article published on 9 October 1995

Barrier thickness matters

scientific article published on November 6, 2011

Bi-potential Behaviour of Cytotrophoblasts in First Trimester Chorionic Villi

scientific article published in April 2006

Biobanking of different body fluids within the frame of IVF-a standard operating procedure to improve reproductive biology research.

scientific article published on 26 November 2016

CD74-Downregulation of Placental Macrophage-Trophoblastic Interactions in Preeclampsia

scientific article published on 19 May 2016

Caspases rather than calpains mediate remodelling of the fodrin skeleton during human placental trophoblast fusion

scientific article published on 2 October 2009

Challenges and Driving Forces for Business Plans in Biobanking

scientific article published on 24 March 2017

Characterization of fetal cells from the maternal circulation by microarray gene expression analysis--could the extravillous trophoblasts be a target for future cell-based non-invasive prenatal diagnosis?

scientific article published on 9 November 2013

Circulating fetal DNA in maternal plasma is increased in pregnancies at high altitude and is further enhanced by preeclampsia

Complex patterns of GCM1 mRNA and protein in villous and extravillous trophoblast cells of the human placenta.

scientific article

Concerted Upregulation of CLP36 and Smooth Muscle Actin Protein Expression in Human Endometrium during Decidualization

scientific article published in 2005

Correction to: Expression of matrix metalloproteinase 12 is highly specific for non-proliferating invasive trophoblasts in the first trimester and temporally regulated by oxygen-dependent mechanisms including HIF-1A.

scientific article published on 13 December 2017

Cryogenic and low temperature preservation of human placental villous explants - a new way to explore drugs in pregnancy disorders

scientific article published in February 2011

Cytochrome P450 subfamily 2J polypeptide 2 expression and circulating epoxyeicosatrienoic metabolites in preeclampsia

scientific article published on 15 November 2012

Cytogenetic and DNA-fingerprint characterization of choriocarcinoma cell lines and a trophoblast/choriocarcinoma cell hybrid.

scientific article

Cytokeratin Antibodies as Differential Markers of Trophoblast and Fetomaternal Syncytial Plaques in the Sheep Placentome

scientific article published in November 2007

Cytotoxic Effect of Advanced Glycation end Products

scientific article published in January 2009

DNA methylation heterogeneity defines a disease spectrum in Ewing sarcoma.

scientific article

Detection of fetal DNA and RNA in placenta-derived syncytiotrophoblast microparticles generated in vitro

scientific article published in November 2004

Development of early non-invasive markers and means for the diagnosis and progression monitoring of preeclampsia and tailoring putative therapies (project pregenesys 037244)

article

Development of the placental villous tree and its consequences for fetal growth

scientific article published in September 2000

Developmental biology of the placenta and the origins of placental insufficiency

scientific article published in October 2004

Differences in d-chiro-inositol-phosphoglycan expression between first and third trimester human placenta

scientific article published on 16 October 2012

Differential expression of VE-cadherin and VEGFR2 in placental syncytiotrophoblast during preeclampsia - New perspectives to explain the pathophysiology

scientific article

Distribution of decidual natural killer cells and macrophages in the neighbourhood of the trophoblast invasion front: a quantitative evaluation

scientific article published on 18 October 2013

Disturbed Placental Imprinting in Preeclampsia Leads to Altered Expression of DLX5, a Human-Specific Early Trophoblast Marker

scientific article published on 13 September 2017

Divergent trophoblast invasion and apoptosis in placental bed spiral arteries from pregnancies complicated by maternal anemia and early-onset preeclampsia/intrauterine growth restriction

scientific article published in February 2006

Does 2D-Histologic identification of villous types of human placentas at birth enable sensitive and reliable interpretation of 3D structure?

scientific article published on 19 October 2015

Effect of high oxygen on placental function in short-term explant cultures

scientific article published on 21 February 2007

Effects of calcium, magnesium, low-dose aspirin and low-molecular-weight heparin on the release of PP13 from placental explants

scientific article published on 17 December 2010

Effects of circulating and local uteroplacental angiotensin II in rat pregnancy

scientific article published on 7 June 2010

Effects of oxygen on cell turnover and expression of regulators of apoptosis in human placental trophoblast.

scientific article published on 21 December 2007

Effects of placental protein 13 on the cardiovascular system in gravid and non-gravid rodents

scientific article published on 8 February 2013

Effects of vitamins C and E, acetylsalicylic acid and heparin on fusion, beta-hCG and PP13 expression in BeWo cells

scientific article published on 29 March 2010

Endogenous retroviral syncytin: compilation of experimental research on syncytin and its possible role in normal and disturbed human placentogenesis

scientific article published on 4 June 2004

Endoglandular trophoblast, an alternative route of trophoblast invasion? Analysis with novel confrontation co-culture models

scientific article published on 22 February 2010

Endothelin-1 Stimulates Proliferation of First-Trimester Trophoblasts via the A- and B-Type Receptor and Invasion via the B-Type Receptor

scientific article published in November 2011

Endovascular trophoblast invasion: implications for the pathogenesis of intrauterine growth retardation and preeclampsia

scientific article

Evidence for a cGMP gated cation channel in photoreceptor cell membranes of Sepia officinalis

scientific article published on 8 May 1995

Evidence from the very beginning: endoglandular trophoblasts penetrate and replace uterine glands in situ and in vitro

scientific article published on 22 October 2015

Expression of CD24 and Siglec-10 in first trimester placenta: implications for immune tolerance at the fetal-maternal interface

scientific article published on 23 December 2016

Expression of a Cytokeratin 18 Neo-epitope is a Specific Marker for Trophoblast Apoptosis in Human Placenta

scientific article published in January 2001

Expression of matrix metalloproteinase 12 is highly specific for non-proliferating invasive trophoblasts in the first trimester and temporally regulated by oxygen-dependent mechanisms including HIF-1A.

scientific article published on 9 October 2017

Expression of serum amyloid A4 in human trophoblast-like choriocarcinoma cell lines and human first trimester/term trophoblast cells

scientific article published on 7 June 2014

Expression of the actin stress fiber-associated protein CLP36 in the human placenta

scientific article published on 12 April 2006

Extracellular matrix components of the placental extravillous trophoblast: immunocytochemistry and ultrastructural distribution

scientific article

Extracellular matrix components of the placental extravillous trophoblast: immunocytochemistry and ultrastructural distribution

scientific article published in September 1996

Extracellular pH modulates the secretion of fibronectin isoforms by human trophoblast

scientific article published in January 2002

Extravillous trophoblast apoptosis – A workshop report

scientific article published in April 2005

Extravillous trophoblasts invade more than uterine arteries: evidence for the invasion of uterine veins

scientific article published on 24 October 2016

Factors Involved in Regulating Trophoblast Fusion: Potential Role in the Development of Preeclampsia

scientific article published in March 2009

Fetal cells and cell free fetal nucleic acids in maternal blood: new tools to study abnormal placentation?

scientific article

Fetal growth restriction: a workshop report.

scientific article published in September 2004

Fibulin-5 expression in the human placenta

scientific article published on 3 February 2011

First trimester serum markers to predict preeclampsia

scientific article published on May 2012

Fusion of villous trophoblast can be visualized by localizing active caspase 8.

scientific article published on 5 April 2009

GDM alters paracrine regulation of feto-placental angiogenesis via the trophoblast

scientific article published on 23 January 2017

Galectin 13 (PP13) Facilitates Remodeling and Structural Stabilization of Maternal Vessels during Pregnancy

scientific article published on 29 June 2019

Governing the invasive trophoblast: current aspects on intra- and extracellular regulation.

scientific article published on 17 March 2010

HO-1 inhibits preadipocyte proliferation and differentiation at the onset of obesity via ROS dependent activation of Akt2.

scientific article published on 19 January 2017

Heparin and aspirin attenuate placental apoptosis in vitro: implications for early pregnancy failure

scientific article (publication date: 2005)

Hofbauer cells of M2a, M2b and M2c polarization may regulate feto-placental angiogenesis

scientific article published on 17 August 2016

Human placental explants in culture: approaches and assessments.

scientific article

Human placental transthyretin in fetal growth restriction in combination with preeclampsia and the HELLP syndrome

scientific article published on 31 July 2012

Human trophoblast contains an intracellular protein reactive with an antibody against CD133--a novel marker for trophoblast.

scientific article published in August 2001

Human trophoblast invasion: new and unexpected routes and functions

scientific article published in October 2018

Hypoxia favours necrotic versus apoptotic shedding of placental syncytiotrophoblast into the maternal circulation

scientific article

IFPA Award in Placentology Lecture: Biology of the placental syncytiotrophoblast--myths and facts

scientific article published on 29 December 2009

IFPA Meeting 2011 workshop report III: Placental immunology; epigenetic and microRNA-dependent gene regulation; comparative placentation; trophoblast differentiation; stem cells

scientific article published on 10 December 2011

IFPA meeting 2008 workshops report

scientific article (publication date: March 2009)

IJMS Special Issue "Molecular and Cellular Mechanisms of Preeclampsia"-Editorial

scientific article published on 07 July 2020

Immunohistochemistry of matrix metalloproteinases (MMP), their substrates, and their inhibitors (TIMP) during trophoblast invasion in the human placenta

scientific article published on 12 December 1997

Impact of constant storage temperatures and multiple warming cycles on the quality of stored red blood cells

scientific article published on 2 August 2013

Implantation and extravillous trophoblast invasion: From rare archival specimens to modern biobanking

scientific article published on 8 February 2017

Implantationsstörungen, Präeklampsie und intrauterine Wachstumsrestriktion

scientific article published in July 2012

In-vitro effects of the antimicrobial peptide Ala8,13,18-magainin II amide on isolated human first trimester villous trophoblast cells

scientific article published on 16 April 2011

Increased placental sFlt-1 but unchanged PlGF expression in late-onset preeclampsia

scientific article published on 11 May 2017

Inhibitory NK receptor recognition of HLA-G: regulation by contact residues and by cell specific expression at the fetal-maternal interface

scientific article

Innovative ways for information transfer in biobanking

scientific article published on 4 November 2013

Invasive depth of extravillous trophoblast correlates with cellular phenotype: a comparison of intra- and extrauterine implantation sites

scientific article published on 20 April 2002

Keratins in the human trophoblast

scientific article published on March 2013

Letter from the guest editors: Cell adhesion, migration, and fusion in placenta

scientific article published on 29 January 2016

Longitudinal Determination of Serum Placental Protein 13 during Development of Preeclampsia

scientific article published in 2008

Low-dose-rate ionizing irradiation for inhibition of secondary cataract formation

scientific article published in March 2001

Magnetomitotransfer: An efficient way for direct mitochondria transfer into cultured human cells

scientific article published on 21 October 2016

Maternal-fetal interactions, predictive markers for preeclampsia, and programming

scientific article published on 04 December 2014

Maternal-placental interactions and fetal programming

scientific article published on 28 June 2013

Matrix metalloproteinases-2, -3 and -9 in human term placenta

scientific article published on 7 June 2007

Mesenchymal stromal cells from the human placenta promote neovascularization in a mouse model in vivo

scientific article published on 26 April 2014

Metalloprotease dependent release of placenta derived fractalkine

scientific article published on 13 March 2014

Minimal Alteration in the Ratio of Circulatory Fetal DNA to Fetal Corticotropin-Releasing Hormone mRNA Level in Preeclampsia

scientific article published in 2006

Multiple injections of anti-mouse β2glycoprotein 1 antibody induce FcRγ-dependent fetal growth restriction (FGR) in mice

scientific article published on 25 April 2012

N-cadherin knockdown leads to disruption of trophoblastic and endothelial cell interaction in a 3D cell culture model - New insights in trophoblast invasion failure

scientific article published on 12 December 2017

Na+−Ca2+,K+ exchange in bovine retinal rod outer segments: quantitative characterization of normal and reversed mode

scientific article published in January 1994

New insights into the biology of preeclampsia

scientific article

Nucleic acid sequence of feline preprorelaxin and its localization within the feline placenta.

scientific article

OS066. Intrauterine CYP2J2 expression and circulatingepoxyeicosatrienoic acid levels in preeclampsia

scientific article

Oxidatively modified LDL particles in the human placenta in early and late onset intrauterine growth restriction

scientific article published in December 2013

Oxygen as modulator of trophoblast invasion

scientific article published on 09 February 2009

Oxygen modulates the response of first-trimester trophoblasts to hyperglycemia

scientific article published on 3 November 2011

PP015. Differential expression of Nrf2 and VEGF in human placental beds from normal and pregnancies complicated with preeclampsia and IUGR.

scientific article published on 13 June 2012

PP019. A new player in preeclampsia: The NF-E2-related factor 2 (NRF2).

scientific article

PP033. Oxidized LDL particles in the placenta of intrauterine growth restriction (IUGR) subgroups

scientific article

Pathogenesis of Intrauterine Growth Restriction (IUGR)—Conclusions Derived from a European Union Biomed 2 Concerted Action Project ‘Importance of Oxygen Supply in Intrauterine Growth Restricted Pregnancies’—A Workshop Report

scientific article published on 01 April 2002

Personalized Therapy Against Preeclampsia by Replenishing Placental Protein 13 (PP13) Targeted to Patients With Impaired PP13 Molecule or Function

scientific article published on 22 September 2017

Pharmacokinetics of placental protein 13 after intravenous and subcutaneous administration in rabbits.

scientific article published on 3 July 2018

Phospholipid scramblase 1 (PLSCR1) in villous trophoblast of the human placenta

scientific article published on 2 November 2014

Physical Activity and Sedentary Time in Pregnancy: An Exploratory Study on Oxidative Stress Markers in the Placenta of Women with Obesity

scientific article published on 05 May 2022

Pigment epithelium-derived factor (PEDF): a novel trophoblast-derived factor limiting feto-placental angiogenesis in late pregnancy.

scientific article published on 8 June 2016

Pixelwise quantification of placental perfusion visualized by 3D power Doppler sonography

scientific article published on 10 May 2012

Placenta trophoblast fusion

scientific article published on January 2008

Placenta-bound and Body Fluid PP13 and its mRNA in Normal Pregnancy Compared to Preeclampsia, HELLP and Preterm Delivery

scientific article published in February 2011

Placental Angiogenesis, Maternal and Fetal Vessels – A Workshop Report

scientific article published in April 2007

Placental Protein 13 Administration to Pregnant Rats Lowers Blood Pressure and Augments Fetal Growth and Venous Remodeling

scientific article

Placental and trophoblastic in vitro models to study preventive and therapeutic agents for preeclampsia

scientific article published on February 2011

Placental expression of d-chiro-inositol phosphoglycans in preeclampsia

scientific article published in October 2012

Placental expression of sFlt-1 and PlGF in early preeclampsia vs. early IUGR vs. age-matched healthy pregnancies

scientific article published on 10 February 2017

Placental fractalkine is up-regulated in severe early-onset preeclampsia

scientific article published on 11 March 2015

Placental fractalkine mediates adhesion of THP-1 monocytes to villous trophoblast

scientific article published on 8 January 2015

Placental markers of folate-related metabolism in preeclampsia

scientific article published in September 2011

Placental mesenchymal stromal cells derived from blood vessels or avascular tissues: what is the better choice to support endothelial cell function?

scientific article published in January 2015

Placental morphology: from molecule to mother -- a dedication to Peter Kaufmann -- a review.

scientific article published on 15 March 2006

Placental origins of preeclampsia: challenging the current hypothesis

scientific article published on 07 February 2008

Placental pathology in pregnancy complications

scientific article published on February 1, 2011

Placental protein 13 (PP13) stimulates rat uterine vessels after slow subcutaneous administration

scientific article published on 27 March 2019

Placental protein 13 (PP13)-induced vasodilation of resistance arteries from pregnant and nonpregnant rats occurs via endothelial-signaling pathways

scientific article published on 19 May 2017

Placental protein 13 (PP13): a new biological target shifting individualized risk assessment to personalized drug design combating pre-eclampsia

scientific article

Pre-eclampsia and Maternal Anaemia Display Reduced Apoptosis and Opposite Invasive Phenotypes of Extravillous Trophoblast

scientific article published in May 2003

Pre-eclampsia as a 'three stage problem'--a workshop report.

scientific article published in July 2004

Predicting the Risk to Develop Preeclampsia in the First Trimester Combining Promoter Variant -98A/C of LGALS13 (Placental Protein 13), Black Ethnicity, Previous Preeclampsia, Obesity, and Maternal Age.

scientific article published on 21 July 2017

Prediction of preeclampsia - a workshop report

scientific article published on 03 December 2007

Preeclampsia - Aetiology, Current Diagnostics and Clinical Management, New Therapy Options and Future Perspectives

scientific article

Preeclampsia: Placental Origins, New Predictors and New Therapeutic Strategies

scientific article published in November 2007

Preface

scientific article published in March 2009

Pregenesys pre-eclampsia markers consensus meeting: What do we require from markers, risk assessment and model systems to tailor preventive strategies?

scientific article published on 23 December 2010

Proliferative responses in the placenta after endotoxin exposure in preterm fetal sheep

scientific article published on 17 October 2007

Quality Matters: 2016 Annual Conference of the National Infrastructures for Biobanking

scientific article

Regulation of proliferation and apoptosis during development of the preimplantation embryo and the placenta

scientific article published in December 2005

Retracted: The Role of the Carbohydrate Recognition Domain of Placental Protein 13 (PP13) in Pregnancy Evaluated with Recombinant PP13 and the DelT221 PP13 Variant

retracted article

Role of a fetal defence mechanism against oxidative stress in the aetiology of preeclampsia.

scientific article published in July 2009

Sequential Steps During Vasculogenesis and Angiogenesis in the Very Early Human Placenta

scientific article published in June 2006

Sequential expression of VEGF and its receptors in human placental villi during very early pregnancy: differences between placental vasculogenesis and angiogenesis.

scientific article

Soluble factors of amnion-derived cells in treatment of inflammatory and fibrotic pathologies

scientific article published on January 2013

Soluble factors released by placental villous tissue: Interleukin-1 is a potential mediator of endothelial dysfunction

scientific article published in February 2005

Spatial and Temporal Distribution of Tie-1 and Tie-2 During Very Early Development of the Human Placenta

scientific article published in June 2006

Sustainability in Biobanking: Model of Biobank Graz

scientific article published on December 2015

Syncytial fusion of human trophoblast depends on caspase 8

scientific article published on 12 September 2003

TNF-α alters the inflammatory secretion profile of human first trimester placenta

scientific article published on 11 January 2016

The 'reference trap' revisited: examples of the dangers in using ratios to describe fetoplacental angiogenesis and trophoblast turnover.

scientific article

The Distribution of Macrophages in Spiral Arteries of the Placental Bed in Pre-eclampsia Differs from that in Healthy Patients

scientific article published in March 1999

The Salivary Scavenger and Agglutinin (SALSA) in Healthy and Complicated Pregnancy

scientific article published in February 2016

The anatomy of the normal placenta

scientific article published on 28 August 2008

The art of identification of extravillous trophoblast

scientific article published on 23 December 2010

The choriocarcinoma cell line BeWo: syncytial fusion and expression of syncytium-specific proteins

scientific article published on 9 August 2010

The effects of Nrf2 deletion on placental morphology and exchange capacity in the mouse

scientific article published on 16 September 2016

The feto-maternal interface: setting the stage for potential immune interactions

scientific article published on June 2007

The fibrinoids of the human placenta: origin, composition and functional relevance.

scientific article

The first trimester human trophoblast cell line ACH-3P: a novel tool to study autocrine/paracrine regulatory loops of human trophoblast subpopulations--TNF-alpha stimulates MMP15 expression

scientific article

The human placenta is encircled by a ring of smooth muscle cells.

scientific article published on January 2000

The paradox of caspase 8 in human villous trophoblast fusion

scientific article published on 30 December 2009

The placental exposome: placental determinants of fetal adiposity and postnatal body composition

scientific article published on 08 October 2013

The trophoblast plug during early pregnancy: a deeper insight

scientific article published on 10 August 2016

The trophoblast survival capacity in preeclampsia.

scientific article published on 6 November 2017

The vitamin E-binding protein afamin increases in maternal serum during pregnancy

scientific article published on 24 April 2014

Traditional and New Routes of Trophoblast Invasion and Their Implications for Pregnancy Diseases

scientific article published on 31 December 2019

Trophoblast Apoptosis and Placental Development—A Workshop Report

scientific article published in March 2000

Trophoblast Fusion

scientific article published on January 1, 2011

Trophoblast and the Endometrium—A Workshop Report

scientific article published on 01 April 2004

Trophoblast differentiation, fetal growth restriction and preeclampsia

scientific article published in January 2011

Trophoblast fusion: fusogenic proteins, syncytins and ADAMs, and other prerequisites for syncytial fusion

scientific article published on 7 February 2006

Trophoblast invasion and oxygenation of the placenta: measurements versus presumptions

scientific article published on 06 June 2013

Trophoblast retrieval and isolation from the cervix: origins of cervical trophoblasts and their potential value for risk assessment of ongoing pregnancies

scientific article published on 28 March 2018

Trophoblast turnover in health and disease

scientific article published in May 2002

Trophoblastic invasion in vitro and in vivo: similarities and differences

scientific article published on 11 July 2008

Trophoblasts Reduce the Vascular Smooth Muscle Cell Proatherogenic Response

article

Ultrasound detection of placental insufficiency in women with 'unexplained' abnormal maternal serum screening results.

scientific article

Unterschiede in der Trophoblastinvasion bei der Tubar- und Intrauteringravidität

scientific article published in June 2002

Untersuchungen des maternalen und fetalen Serumlipidprofils und des oxidierten ‚Low Density‘ Lipoproteins im plazentaren Gewebe bei Präeklampsie und normotensiven Schwangerschaften

scientific article published on 29 October 2012

Vascular biology in implantation and placentation.

scientific article

Vasculogenesis and angiogenesis in the early human placenta

scientific article published on 15 June 2007

Vasculogenesis and angiogenesis in the endometrium during menstrual cycle and implantation

scientific article published on 29 May 2009

Vermehrte Expression der induzierbaren NO-Synthase (iNOS) in Makrophagen des Plazentabettes bei schwerer Präeklampsie

scientific article published in September 2004

Villous cytotrophoblast regulation of the syncytial apoptotic cascade in the human placenta

scientific article published in 1998

Villous sprouting: fundamental mechanisms of human placental development.

scientific article

d-chiro-inositol phosphoglycan expression in human placenta at term in diabetes