Abstract:
:Late follicular progesterone (P) elevation continues to complicate a significant part of assisted reproductive technologies (ART) cycles, despite the ardent employment of gonadotropin releasing hormone (GnRH) analogues. In women with good ovarian reserve, late follicular P elevation is believed to be the result of the controlled ovarian stimulation (COS) itself, multiple follicular development and excessive ovarian steroidogenic activity. These mechanisms do not seem to be plausible in women with low ovarian reserve. In these women, excessive COS achieve a small number of pre-ovulatory follicles, which is not coupled to considerable ovarian steroidogenic activity. Therefore, other mechanisms should be pursued and explored. Delicate paracrine and autocrine mechanisms within the oocyte-cumulus complex were suggested to preserve the integrity of the pre-ovulatory follicle, including inhibition of P increase and follicular luteinization. However, clinical studies to demonstrate the disruption of these mechanisms in cases with low ovarian reserve and ageing oocytes are still lacking. Late follicular progesterone/estradiol (P/E2) ratio was introduced into clinical practice as a more appropriate way to analyze P rise in women undergoing COS to control for the E2 increase. The current hypothesis claims that in a follicular environment were the mechanism that prevent premature luteinization is disrupted, independent to LH surge; P rise at the late follicular phase may relatively bypass normal E2 production, at the pre-ovulatory stage of steroidogenesis, causing a rise in the P/E2 ratio. Therefore, in women with low ovarian reserve and few pre-ovulatory follicles, undergoing conventional COS, a negative (reverse) correlation between number of maturing follicles and P/E2 ratio may support the existence of such a mechanism as its disruption, while a no or a positive correlation may disapprove it.
journal_name
Med Hypothesesjournal_title
Medical hypothesesauthors
Younis JSdoi
10.1016/j.mehy.2019.02.047subject
Has Abstractpub_date
2019-04-01 00:00:00pages
126-128eissn
0306-9877issn
1532-2777pii
S0306-9877(18)30935-6journal_volume
125pub_type
杂志文章abstract::Regulation of ion transport across the airway mucosa may be involved in the mechanisms producing hyperreactivity and asthma. Atrial Natriuretic Peptide (ANP) has been proposed to participate in the pathogenesis of asthma, and it has been found to have a bronchodilatory effect on asthmatic patients. Experimental eviden...
journal_title:Medical hypotheses
pub_type: 杂志文章
doi:10.1016/0306-9877(91)90167-w
更新日期:1991-09-01 00:00:00
abstract::This hypothesis clearly proposes the true and previously undiscovered cause of male homosexuality or bisexuality and in most cases the predictability in infancy of the development of this sexuality in adulthood. It is based on compelling new evidence which has accumulated over many years. The fetal and neonatal period...
journal_title:Medical hypotheses
pub_type: 杂志文章
doi:10.1016/j.mehy.2016.06.006
更新日期:2016-09-01 00:00:00
abstract::Whether retroviral integration is a phenomenon specific to properties of the surrounding genomic region is a widely debated question. In this paper we attempt to enlight the involvement of genomic regions prone to DNA double strand breaks in such process, as well as the more general concept of genome plasticity concer...
journal_title:Medical hypotheses
pub_type: 杂志文章
doi:10.1016/s0306-9877(02)00410-3
更新日期:2003-02-01 00:00:00
abstract::Following observation of fatigue syndromes in people who have been occupationally exposed to pesticides and insecticides which exert their toxicity through the GABAa receptor, we have formulated the hypothesis that fatigue syndromes in general may be secondary to altered sensitivity of the GABAa receptor. We discuss t...
journal_title:Medical hypotheses
pub_type: 杂志文章
doi:10.1016/0306-9877(94)90065-5
更新日期:1994-10-01 00:00:00
abstract::Delivery of large DNA constructs is necessary for combinatorial, anti-aging gene therapy. However, this is hindered by the lack of a non-inflammatory vector with sufficient packaging space and the ability to effectively spread through tissue. It is possible that a mitochondrion, altered to be able to secrete therapeut...
journal_title:Medical hypotheses
pub_type: 杂志文章
doi:10.1016/j.mehy.2018.05.014
更新日期:2018-08-01 00:00:00
abstract::Both epidemiological and experimental studies have shown that impaired growth in utero due to maternal malnutrition, resulting in low birth weight, is associated with a high incidence of glucose intolerance, insulin resistance, and type 2 diabetes in adult life. Maternal malnutrition is a worldwide problem and unavoid...
journal_title:Medical hypotheses
pub_type: 杂志文章
doi:10.1016/j.mehy.2005.12.024
更新日期:2006-01-01 00:00:00
abstract:BACKGROUND:Short-term acute care public county hospitals in the US were a mainstay of much "safety net" medical care in the early twentieth century. The private sector currently provides much of what was in the past public medical care. Does this transition affect health care indices? METHODS:The presence of public ho...
journal_title:Medical hypotheses
pub_type: 杂志文章
doi:10.1016/j.mehy.2019.109265
更新日期:2019-11-01 00:00:00
abstract::Human papillomavirus (HPV) type 16 is causally associated with a subset of oral cancers, predominantly those cancers arising in the oropharynx (OP). Increased HPV16 E6 and E7 oncogene expressions are responsible for the malignant transmission in these cancers. ErbB-2 is the family member most closely implicated in hum...
journal_title:Medical hypotheses
pub_type: 杂志文章
doi:10.1016/j.mehy.2004.03.013
更新日期:2004-01-01 00:00:00
abstract::This paper discusses a mechanism for converting heterochromatin into the more relaxed state of euchromatin. Actuation of such state conversion stems from disassembly of internal vesicles that are incapable of surviving when trapped within the inner chamber of mammalian nuclei. ...
journal_title:Medical hypotheses
pub_type: 杂志文章
doi:10.1016/s0306-9877(02)00233-5
更新日期:2002-11-01 00:00:00
abstract::Immune competence is considered as a state of equilibrium between humoral and cellular immunity. This notion fits well with the functionally antagonistic cytokine profiles in cell groups of CD4(+)-helper cells as described by Mosmann and Coffman. The Th-1 cells release mainly IL-2, IL-12 and IFN gamma and thereby stim...
journal_title:Medical hypotheses
pub_type: 杂志文章
doi:10.1016/s0306-9877(96)90130-9
更新日期:1996-06-01 00:00:00
abstract::Traumatic iris sphincter tear has been thought to occur secondary to anteroposterior compression of the globe with defined forces lead to equatorial expansion and active pull along the corneoscleral junction and sphincter tear. However, here in this report, we elaborate the additional forces involved in the traumatic ...
journal_title:Medical hypotheses
pub_type: 杂志文章
doi:10.1016/j.mehy.2018.11.013
更新日期:2019-01-01 00:00:00
abstract::For almost 70 years, essential fatty acid deficiency has been known to be associated with skin disorders, vessel abnormalities, and increased tumorigenesis. However, the underlying molecular and cellular mechanism is largely unknown. Recently, it has been reported that essential fatty acids regulate cell adhesion by m...
journal_title:Medical hypotheses
pub_type: 杂志文章
doi:10.1054/mehy.1998.1191
更新日期:2000-09-01 00:00:00
abstract::Intra-peritoneal adhesions ensuing from surgery or infection may lead to chronic pelvic pain, bowel obstruction, infertility and additional invasive surgery to resolve adhesion-related complications. As a result adhesions are a major clinical, social and economic concern. The cumulative year-on-year direct costs of ad...
journal_title:Medical hypotheses
pub_type: 杂志文章
doi:10.1016/j.mehy.2010.11.020
更新日期:2011-03-01 00:00:00
abstract::Some drugs blocking glutamate release produce reduced brain injury in some animal models of cerebral ischemia whereas others lack a clear effect. Meta-analysis is a widely used technique in clinical and epidemiological studies. However, it has never been used in the analysis of preclinical studies. In order to estimat...
journal_title:Medical hypotheses
pub_type: 杂志文章
doi:10.1054/mehy.1998.0831
更新日期:2000-01-01 00:00:00
abstract::Preeclampsia (PE) and gestational diabetes mellitus (GDM) are two of the most common medical complications of pregnancy, with risks for both mother and child. Like many other antepartum complications, PE and GDM occur only in pregnancy. However, it is not clear if pregnancy itself is the cause of these complications o...
journal_title:Medical hypotheses
pub_type: 杂志文章
doi:10.1016/j.mehy.2012.04.019
更新日期:2012-07-01 00:00:00
abstract::Inflammatory eye diseases such as uveitis are common and may eventually result in vision loss. Iron can play a critical role in ocular inflammation via promoting the generation of oxygen free radicals and it is also nutritionally essential for microbial growth. Considering this involvement of iron in inflammation and ...
journal_title:Medical hypotheses
pub_type: 杂志文章
doi:10.1016/j.mehy.2017.03.029
更新日期:2017-06-01 00:00:00
abstract::In recent years a male-specific but species non-specific mammalian cell surface antigen, the H-Y antigen, has been demonstrated on somatic cells as well as on sperm. This raises some questions regarding unforeseen risks of certain medical procedures, notably blood transfusion. It is stressed that especially the possib...
journal_title:Medical hypotheses
pub_type: 杂志文章
doi:10.1016/0306-9877(80)90132-2
更新日期:1980-11-01 00:00:00
abstract::Genome imprinting has an essential role in normal embryonal mammalian development. Starting early in differentiation, the transcripts of certain human genes, e.g. the paternally-H19 and the maternally-imprinted IGF2, are expressed in specific tissues and organs during fetal life. In several malignant disorders, imprin...
journal_title:Medical hypotheses
pub_type: 杂志文章
doi:10.1016/0306-9877(94)90062-0
更新日期:1994-08-01 00:00:00
abstract::It is increasingly admitted that Crohn's disease and ulcerative colitis, the two entities of inflammatory bowel disease, are initiated and reactivated by environmental factors in genetically susceptible hosts, and result from aberrant immune response to specific intestinal microbes, in the context of altered compositi...
journal_title:Medical hypotheses
pub_type: 杂志文章
doi:10.1016/j.mehy.2018.03.009
更新日期:2018-06-01 00:00:00
abstract::Treatment with non-selective beta-blockers has been proposed to have an indirect antiviral activity acting via an enhanced performance of the immune system, and the mechanism of this activity has been laid out earlier. Experimental and clinical findings are presented that corroborate the hypothesis that inhibiting the...
journal_title:Medical hypotheses
pub_type: 杂志文章
doi:10.1016/j.mehy.2004.06.030
更新日期:2005-01-01 00:00:00
abstract::A mechanism of action for Panax ginseng (PG) and Eleutherococcus senticosus (ES) is proposed which explains how they could produce the paradoxical effect of sometimes increasing and sometimes decreasing the stress response. The mechanism suggests that this biphasic effect results from increased occupancy of positive a...
journal_title:Medical hypotheses
pub_type: 杂志文章
doi:10.1054/mehy.2000.1163
更新日期:2001-05-01 00:00:00
abstract::A comparison is made of the x-ray induced thyroid adenocarcinoma in the rat by the in-vitro, in-vivo method of Clifton et al. with previous data of Doniach on in-vivo irradiation in whole animals. The Clifton data consists of only one point at 500 rad. I have assumed that the probability of transformation per viable c...
journal_title:Medical hypotheses
pub_type: 杂志文章
doi:10.1016/0306-9877(84)90070-7
更新日期:1984-04-01 00:00:00
abstract::Stress, in its many forms, is long associated with the etiology and course of schizophrenia. The mechanisms mediating the impacts of stress are not fully elucidated. Here it is proposed that stress induced cortisol alters kynurenic acid (KA) and quinolinic acid (QA) in the cortex and amygdala/striatum, respectively. T...
journal_title:Medical hypotheses
pub_type: 杂志文章
doi:10.1016/j.mehy.2010.08.029
更新日期:2011-01-01 00:00:00
abstract::This paper outlines a method of demonstrating hepatitis B virus (HBV)-related transcriptional activity based on the random amplification of cDNA ends (RACE) protocol. Following RNA extraction from the appropriate tissue, cDNA is synthesized using a long oligo d(T) based primer containing unique 5' oligonucleotide sequ...
journal_title:Medical hypotheses
pub_type: 杂志文章
doi:10.1016/0306-9877(95)90056-x
更新日期:1995-08-01 00:00:00
abstract::A meniscal graft extrusion is still an unresolved problem that affects most patients after a meniscal transplantation. Despite the advances in surgical techniques, together with the improved methods for a meniscal allograft sizing, success is only observed in up to 75% of patients after they experience a meniscal allo...
journal_title:Medical hypotheses
pub_type: 杂志文章
doi:10.1016/j.mehy.2017.02.003
更新日期:2017-04-01 00:00:00
abstract::An increase in pro-inflammatory cytokines, decrease in endothelial nitric oxide (eNO) and adiponectin levels and an alteration in hypothalamic peptides and gastrointestinal hormones such as incretins and cholecystokinin that regulate satiety, hunger, and food intake occur in metabolic syndrome. Thus, metabolic syndrom...
journal_title:Medical hypotheses
pub_type: 杂志文章
doi:10.1016/j.mehy.2010.11.013
更新日期:2011-03-01 00:00:00
abstract::Antisense oligonucleotides (oligos) have demonstrated efficacy for the treatment of various cancers, infectious diseases and metabolic disorders. While most studies have utilized single oligos either administered alone, or more recently in combination therapy with other drugs, some investigators have administered more...
journal_title:Medical hypotheses
pub_type: 杂志文章
doi:10.1016/j.mehy.2004.12.032
更新日期:2005-01-01 00:00:00
abstract::Recent findings demonstrate the vital role of endothelial progenitor cells in the homeostasis of the vessel wall and the development of atherosclerosis. Endothelial progenitor cells (EPCs) play important roles in repair-to-injury of arteries. Many evidences have shown Cardiovascular risk factors closely correlated wit...
journal_title:Medical hypotheses
pub_type: 杂志文章
doi:10.1016/j.mehy.2007.06.041
更新日期:2008-01-01 00:00:00
abstract::In this editorial, we provide concise suggestions to help individuals decide what scientific papers to read and how to read them. We do so because--like others--we are frequently asked by people with interest in science as to how to effectively surf today's information tsunami. This is particularly important in, but n...
journal_title:Medical hypotheses
pub_type: 社论
doi:10.1016/j.mehy.2009.05.002
更新日期:2009-09-01 00:00:00
abstract::In mathematics and physics, chaos theory deals with the behavior of certain nonlinear dynamical systems that under certain conditions exhibit a phenomenon known as chaos, which is characterised by a sensitivity to initial conditions. Mathematicians paradoxically call such states of order chaos and distinguish them fro...
journal_title:Medical hypotheses
pub_type: 杂志文章
doi:10.1016/j.mehy.2006.02.032
更新日期:2006-01-01 00:00:00