Abstract：
:The modified base 5-methylcytidine has been found in the DNA of a number of different eukaryotic cells where it occurs principally in the dinucleotide sequence -CmpG- which is present as a palindrome in double-strand nucleic acid molecules. There is considerable evidence to indicate and suggest that 5-methylcytosine serves as a regulatory signal in eukaryotic gene expression. Replication of DNA containing -CmpG- gives rise to daughter DNA molecules containing new -CpG- dinucleotide sequences in which the cytidine residues are not methylated. Methylation of these residues is carried out by a methylase enzyme using S-adenosyl-L-methionine as a specific methyl group donor. The model discussed in the present communication tries to explain in chemical and biological terms the mechanism of the methylation reaction. The first reactions of the scheme are well known through the work of other investigators. However, we introduce a new concept into our reaction mechanism by postulating the direct involvement of S-adenosyl-L-methionine in the reaction through its covalent attachment to the cytosine ring followed by a specific ring closure and methylation involving transfer of a hydride ion. The model also gives a possible explanation of mechanism of interaction of dimethyl sulphoxide with the enzyme systems of certain eukaryotic cells, which are altered or changed in the regulation of gene expression by this chemical reagent.
journal_name
Med Hypothesesjournal_title
Medical hypothesesauthors
Hawtrey AO,Ariatti Mdoi
10.1016/0306-9877(84)90117-8subject
Has Abstractpub_date
1984-10-01 00:00:00pages
125-34issue
2eissn
0306-9877issn
1532-2777pii
0306-9877(84)90117-8journal_volume
15pub_type
杂志文章abstract：:Abdominal aortic aneurysms (AAAs) have traditionally been attributed to atherosclerosis, although there is increasing epidemiological, biochemical and genetic evidence that aneurysmal arterial disease is different from occlusive atherosclerosis. One of the most consistent biochemical findings in the aneurysmal aorta i...
journal_title：Medical hypotheses
pub_type： 杂志文章
doi：10.1016/0306-9877(95)90193-0
更新日期：1995-07-01 00:00:00
abstract：:The authors hypothesize that the impairment of hypothalamic-pituitary-gonadal axis in patients suffering from anorexia nervosa depends (at least in part) on the increased sensitivity to endogenous melatonin. The hypothesis is based mainly on the following facts: (1) melatonin is well known to exert an inhibitory effec...
journal_title：Medical hypotheses
pub_type： 杂志文章
doi：10.1054/mehy.1997.0631
更新日期：1999-02-01 00:00:00
abstract：:Trypanosomiasis is common in Africa and South America. The surface of trypanosomes is covered by glycosyl phosphatidylinositol (GPI)-anchored variant surface glycoprotein (VSG) that contains the fatty acid myristate (14:0) as its lipid moiety that is essential for its survival. Myristic acid, being a saturated fatty a...
journal_title：Medical hypotheses
pub_type： 杂志文章
doi：10.1016/j.mehy.2009.11.002
更新日期：2010-04-01 00:00:00
abstract：:It has been hypothesised that antiallergic medications (AAMs) like montelukast and levocetirizine both the two bitter chloro compounds could be repurposed either alone or combinedly as an antiviral against SARS-CoV-2, like chloroquine/hydroxychloroquine (CQ/HCQ), another two bitter chloro compounds. Both AAMs and CQ/H...
journal_title：Medical hypotheses
pub_type： 信件
doi：10.1016/j.mehy.2020.110046
更新日期：2020-11-01 00:00:00
abstract：:The terminology of cerebellar ataxias encompasses a variety of sporadic and inherited debilitating diseases. Patients exhibit disabling deficits such as dysmetria, kinetic tremor and ataxia of stance/gait. We are currently lacking effective treatments in degenerative cerebellar ataxias. Animal models of cerebellar dis...
journal_title：Medical hypotheses
pub_type： 杂志文章
doi：10.1016/j.mehy.2008.01.009
更新日期：2008-01-01 00:00:00
abstract：:Endometriosis is a common gynaecological disorder causing pain, infertility, and emotional distress. Evidence presented here suggests that abnormal production of tumour necrosis factor-alpha (TNF-alpha) is required for the establishment and maintenance of endometriosis and also is responsible for the associated infert...
journal_title：Medical hypotheses
pub_type： 杂志文章
doi：10.1016/s0306-9877(02)00336-5
更新日期：2003-01-01 00:00:00
abstract：:Many brilliant and ambitious young women lose their drive for top careers after childbirth. New maternal impulses are at odds with their original ambitions and for many mothers stress and frustration will be the result as they have to combine child care with workweeks of 60-80h to reach or remain at the top. Pregnancy...
journal_title：Medical hypotheses
pub_type： 杂志文章
doi：10.1016/j.mehy.2017.07.002
更新日期：2017-09-01 00:00:00
abstract：:Some cancer patients live many decades after diagnosis while others are not so fortunate. Understanding why this occurs is a fundamental issue in cancer research. We hypothesize that among the factors controlling favorable outcome are a class of genes that we describe as "good oncogenes". These genes have a paradoxica...
journal_title：Medical hypotheses
pub_type： 杂志文章
doi：10.1016/j.mehy.2010.10.015
更新日期：2011-02-01 00:00:00
abstract：:Some genes such as those for histones and RNAs are conserved unchanged through much of evolution and have numerous tandem repeat copies in the genome. It is proposed that as yet undetected 'polystrand' enzymes use such multiple copies as a means of conserving their sequence by comparing the copies and eliminating erro...
journal_title：Medical hypotheses
pub_type： 杂志文章
doi：10.1016/0306-9877(90)90099-z
更新日期：1990-08-01 00:00:00
abstract：:Rushton bodies (RBs) are one of the characteristic features seen in the epithelial lining of odontogenic cysts mainly radicular, dentigerous and odontogenic keratocyst. It has two different histo-morphological appearances; granular and homogeneous. Although widely investigated, the exact pathogenesis and histogenesis ...
journal_title：Medical hypotheses
pub_type： 杂志文章
doi：10.1016/j.mehy.2016.06.007
更新日期：2016-08-01 00:00:00
abstract：:Complex Regional Pain Syndrome (CRPS) has defied a clear unified pathological explanation to date. Not surprisingly, treatments for the condition are limited in number, efficacy and their ability to enact a cure. Whilst many observations have been made of physiological abnormalities, how these explain the condition an...
journal_title：Medical hypotheses
pub_type： 杂志文章
doi：10.1016/j.mehy.2018.07.026
更新日期：2018-10-01 00:00:00
abstract：:Noonan syndrome (NS OMIM 163950) is a relatively common autosomal dominant developmental disorder characterized by short stature, specific facial features, and congenital cardiac anomalies. Approximately 50-66% of cases have defined mutations in the K-ras/Raf/MEK/ERK pathway that lead to constitutive signaling, but a ...
journal_title：Medical hypotheses
pub_type： 杂志文章
doi：10.1016/j.mehy.2009.01.040
更新日期：2009-07-01 00:00:00
abstract：:In normal and hypertensive subjects, many stimuli which increase ACTH secretion also increase blood pressure and conversely, many drugs which decrease ACTH secretion also decrease blood pressure. We postulate that the hypothalamopituitary adrenal axis plays a role in blood pressure regulation in normal and hypertensiv...
journal_title：Medical hypotheses
pub_type： 杂志文章
doi：10.1016/0306-9877(87)90014-4
更新日期：1987-07-01 00:00:00
abstract：:Surgery for intractable affective illnesses has generated considerable controversy over the last century. Deep brain stimulation (DBS) has revolutionized neurosurgical practice, especially in the field of advanced Parkinson's disease and, more recently, in selected medical-refractory cases of obsessive-compulsive diso...
journal_title：Medical hypotheses
pub_type： 杂志文章
doi：10.1016/j.mehy.2005.07.036
更新日期：2006-01-01 00:00:00
abstract：:The available epidemiological data for amyotrophic lateral sclerosis (ALS) support an infectious etiology and lead us to propose a new hypothesis. We examined older epidemiological data concerning categories of the population with increased incidence (aged people, people living in rural areas, farmers, breeders), more...
journal_title：Medical hypotheses
pub_type： 杂志文章
doi：10.1016/j.mehy.2006.04.070
更新日期：2006-01-01 00:00:00
abstract：:Autism continues to be a significant cause of psychosocial pathology in affected children and adults. Until recently, the predominant research thrust to uncover the cause of this condition has been the search for a major nuclear mutation. Although a small percentage of cases do demonstrate such a DNA fault, recent eff...
journal_title：Medical hypotheses
pub_type： 杂志文章
doi：10.1016/j.mehy.2018.10.015
更新日期：2019-01-01 00:00:00
abstract：:On the nature of wellness, stress, netting and the radical gas nitric oxide (NO). The multi-complex role of NO resulted in its discoverers receiving a Nobel award, its presence everywhere and volatility makes it a suitable candidate to be a main signal in an instantaneous communication network. Such network, with the ...
journal_title：Medical hypotheses
pub_type： 杂志文章
doi：10.1016/j.mehy.2007.04.026
更新日期：2008-01-01 00:00:00
abstract：:Superficial fraying, splitting and fibrillation of articular cartilage as a consequence of ageing or mechanical injury is not always associated with joint pain. However, similar cartilage lesions accompanied by synovitis and engorgement of the subchondral vasculature generally is; the disorder being known as osteoarth...
journal_title：Medical hypotheses
pub_type： 杂志文章
doi：10.1016/0306-9877(93)90068-2
更新日期：1993-08-01 00:00:00
abstract：:Scrub typhus is a mite borne infectious disease which has re-emerged in India in the 3rd millennium after years of quiescence. In this review, the authors hypothesize the various factors responsible for resurgence of this disease. The main drivers that could have contributed to the upsurge in scrub typhus cases in pas...
journal_title：Medical hypotheses
pub_type： 杂志文章,评审
doi：10.1016/j.mehy.2018.03.019
更新日期：2018-06-01 00:00:00
abstract：:Preliminary reports have demonstrated that anterior nucleus thalamus high-frequency electrical stimulation (ANT-HFS) is an effective treatment for patients who suffer from medically refractory epilepsy. However, its extensive application has been hampered by the high cost and the unpredictable outcome before the opera...
journal_title：Medical hypotheses
pub_type： 杂志文章
doi：10.1016/j.mehy.2013.06.001
更新日期：2013-09-01 00:00:00
abstract：:This novel, iso-osmo-resistive theory offers electro-resistivity of food components as a new dimension for digestion. Firstly, fats, carbohydrates and proteins differ markedly in their resistivity, which offers a way to monitor them, especially when digestive enzymes cause consistent and distinctive changes. Secondly ...
journal_title：Medical hypotheses
pub_type： 杂志文章
doi：10.1016/j.mehy.2019.109282
更新日期：2019-09-01 00:00:00
abstract：:A role for lipopolysaccharides (endotoxins, LPS) in 7 the pathogenesis of Reye's syndrome (RS) has previously been suggested. Impairment of hepatic LPS clearance can lead to systemic endotoxemia as previous studies by this and other laboratories have suggested for several hepatic disorders including RS. Systemic LPS m...
journal_title：Medical hypotheses
pub_type： 杂志文章
doi：10.1016/0306-9877(92)90115-s
更新日期：1992-11-01 00:00:00
abstract：:Schmorl's nodes (SNs) are common abnormalities in the human spine, which represent herniation of the nucleus pulposus of the intervertebral disc into the adjacent cartilaginous endplate of the vertebra. However, the principle mechanism of SNs is still not fully understood. And the relationship of SNs in the spine and ...
journal_title：Medical hypotheses
pub_type： 杂志文章
doi：10.1016/j.mehy.2009.09.044
更新日期：2010-03-01 00:00:00
abstract：:Genetic linkage studies and genome wide analysis have provided insights into complex medical diseases. Mycobacterium avium ss. paratuberculosis (MAP) causes Johne's disease, an important enteric inflammatory disease mostly studied in ruminant animals. MAP is also the putative cause of Crohn's disease. Moreover, MAP ha...
journal_title：Medical hypotheses
pub_type： 杂志文章
doi：10.1016/j.mehy.2014.09.025
更新日期：2014-12-01 00:00:00
abstract：:Many parasites induce characteristic changes in their host. The effect of Toxoplasma gondii infection on the cerebrum and neuropsychiatric patients has been increasingly emphasized in recent years. T. gondii has a high affinity for brain tissue where tachyzoites may form tissue cysts and persist for a life long time. ...
journal_title：Medical hypotheses
pub_type： 杂志文章
doi：10.1016/j.mehy.2009.04.013
更新日期：2009-11-01 00:00:00
abstract：:Chronic viral liver disease may evolve to cirrhosis. The medical treatment to slow down this passage is based on anti-viral and anti-fibrotic properties of interferon. Recently, we evidenced significant increase of portal vein flow velocity and volume after a prostacyclin analog (iloprost) infusion in subjects without...
journal_title：Medical hypotheses
pub_type： 杂志文章
doi：10.1016/j.mehy.2004.05.017
更新日期：2005-01-01 00:00:00
abstract：:The disturbances of the 11p15.5 chromosomal region are associated with Beckwith-Wiedemann syndrome, Russell-Silver syndrome, Wilms tumor, IMAGe syndrome, and idiopathic hemihyperplasia. The aim of this research was to examine the hypothesis that 11p15.5 initially became unstable in the European population about 200 ye...
journal_title：Medical hypotheses
pub_type： 历史文章,杂志文章
doi：10.1016/j.mehy.2018.09.008
更新日期：2018-12-01 00:00:00
abstract：:Open-angle glaucoma, idiopathic intracranial hypertension, and Meniere's disease are disorders managed by different specialties in medicine viz. ophthalmology, neurology, and otorhinolaryngology respectively. By working in silos, the similarity of these disorders is overlooked. Close inspection of these disorders reve...
journal_title：Medical hypotheses
pub_type： 杂志文章
doi：10.1016/j.mehy.2019.109361
更新日期：2019-11-01 00:00:00
abstract：:The 'Big Bang' is used to describe the origin of the Universe. While such an event could not create itself the expression is graphic. Tissue damage, traumatic, thermal, chemical; bites; insect, animal or human are all bad, but also well known factors which favor and initiate pathogenic activity. Antedating and outrank...
journal_title：Medical hypotheses
pub_type： 杂志文章
doi：10.1016/0306-9877(91)90036-x
更新日期：1991-06-01 00:00:00
abstract：:In the early postnatal period, intraventricular hemorrhage may develop in infants with extremely low birth weights due to hemodynamic instability. One of the most significant factors in intraventricular hemorrhage development is fluctuations in the cerebral blood flow due to left-to-right shunting as a result of paten...
journal_title：Medical hypotheses
pub_type： 杂志文章
doi：10.1016/j.mehy.2018.07.013
更新日期：2018-10-01 00:00:00
