scholarly journals Management of ovarian functions by melatonin

2021 ◽  
Vol 2 ◽  
pp. 16
Author(s):  
Chandana Haldar ◽  
Jayita Pal Chowdhury
Keyword(s):  
Defense Mechanism ◽  
De Novo ◽  
Oocyte Quality ◽  
Melatonin Receptors ◽  
Pars Tuberalis ◽  
Reproductive Techniques ◽  
Molecular Machinery ◽  
Lh Release ◽  
Ovulatory Follicles

Extensive research has unraveled a niche for melatonin that is of great significance for the female reproductive physiology. The potency of melatonin as an antioxidant, anti-inflammatory, and anti-apoptotic agent is being utilized to benefit female reproductive anomalies. Melatonin receptors have been localized in the Supra Chaismatic Nucleus (SCN), pars tuberalis (PT), and the gonads suggesting the regulation of reproduction by melatonin not only at a higher level but also on the gonads through complex interrelated mechanisms. Melatonin secreted by the pineal gland acts on the hypothalamus to regulate gonadotropin-releasing hormone and subsequently gonadotropin (FSH/LH) release from the PT. However, the de novo synthesis of this indoleamine reported in the gonads gave rise to the idea of a more localized action. The mammalian ovary has all the molecular machinery required for the biosynthesis of melatonin and interestingly concentration of melatonin in the follicular fluid of pre-ovulatory follicles is much higher than circulatory melatonin even in humans. This locally produced melatonin has been shown to modulate various pathways governing ovarian steroidogenesis. Further, melatonin and its receptors play a significant role in antioxidant defense mechanism of ovary for follicular growth and maturation. Exposure to stress strongly influences hypothalamic-pituitary-adrenal axis and elevated glucocorticoid levels suppress various ovarian functions including implantation thereby pregnancy. Melatonin acts antagonistically with glucocorticoids, making it crucial for the management of the female reproductive functions/dysfunctions. Usage of melatonin during in vitro fertilization (IVF) procedures has been found to improve oocyte quality, survival, and fecundity. Therefore, in future, melatonin can be implicated as preferable therapeutic especially in IVF and assisted reproductive techniques.

Assisted reproductive research: Laser assisted hatching and spindle detection (spindle view technique)

2004 ◽  
Vol 52 (1) ◽  
pp. 113-123 ◽  
Author(s):  
Katalin Kanyó ◽  
J. Konc ◽  
L. Solti ◽  
S. Cseh
Keyword(s):  
Animal Studies ◽  
Harmful Effect ◽  
Animal Experiments ◽  
Oocyte Quality ◽  
Assisted Hatching ◽  
Safe Procedure ◽  
Living Mouse ◽  
Reproductive Techniques ◽  
Developmental Capacity

Animal experiments are very important for the development of new assisted reproductive techniques (ART) for use in human and animal reproductive medicine. Most technical aspects of reproductive manipulation of humans and animals are very similar, and many components of successful human ART used nowadays have been derived from animal studies. In this study we examined (1) the use of 'non-contact' laser for assisted hatching, (2) whether spindles in living mouse oocytes could safely be imaged/examined by polarisation microscope (polscope) and (3) the influence of environment (e.g. temperature, in vitro culture, etc.) on spindle detection/visualisation. The data of the study presented here show that (1) laser assisted hatching (AH) is a fast, very accurate and safe procedure without any harmful effect on embryo development and it can support very effectively the implantation of embryos, (2) the use of polscope facilitates the evaluation of oocyte quality and the selection of oocytes with spindle, (3) by monitoring the spindle position during intracytoplasmic sperm injection (ICSI), we can reduce spindle damage and increase the chance of fertilisation. Further studies are underway to test the hypothesised connection between spindle birefringence and developmental capacity of oocytes/embryos.

scholarly journals Pyometra does not affect some molecular quality-related parameters of canine oocytes

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Piotr Pawlak ◽  
Ewelina Warzych ◽  
Zofia E. Madeja ◽  
Tomasz Nowak ◽  
Dorota Lechniak
Keyword(s):  
Mrna Level ◽  
Oocyte Quality ◽  
Potential Effect ◽  
Animal Cloning ◽  
Maternal Effect Genes ◽  
Negative Effect ◽  
Reproductive Techniques ◽  
Two Parameters

AbstractCystic endometrial hyperplasia-pyometra complex (CEH/P) significantly perturbs the reproductive performance of affected bitches and ovariohysterectomy (OHE) is a commonly applied treatment. Thus the only way to take advantage of the genetic potential of valuable females is application of assisted reproductive techniques (ART) mainly in vitro embryo production (IVP) or in some exceptional cases animal cloning by somatic cell nuclear transfer (SCNT). The aim of our study was to examine a potential effect of the CEH/P status on the quality of oocytes from females subjected to OHE. In total, 828 immature oocytes collected from ovaries of 33 bitches (21 control, 12 CEH/P) were subjected to genetic analyses (mRNA expression of two maternal-effect genes: GDF-9, OCT4 and mitochondrial DNA – mtDNA - content). Oocytes of CEH/P females were characterized by a higher mtDNA content (471 696) than gametes of their healthy counterparts (368 175; p<0,005). Transcripts for the two genes were detected in all samples and the mRNA level was not affected by the CEH/P status. In conclusion, the CEH/P complex does not exert a negative effect on oocyte quality reflected by the two parameters examined in this study.

The localisation and characterisation of insulin-like growth factor-I receptors and the investigation of melatonin receptors on the hair follicles of seasonal and non-seasonal fibre-producing goats

1996 ◽  
Vol 151 (1) ◽  
pp. 55-63 ◽  
Author(s):  
P Dicks ◽  
C J Morgan ◽  
P J Morgan ◽  
D Kelly ◽  
L M Williams
Keyword(s):  
Hair Follicle ◽  
De Novo ◽  
Dissociation Constants ◽  
Hair Follicles ◽  
Melatonin Receptors ◽  
Pars Tuberalis ◽  
Binding Model ◽  
Outer Root Sheath ◽  
Igf I ◽  
Angora Goats

Abstract To define the hormonal influences that are directly involved in the hair follicle cycles of animals with differing patterns of fibre growth and moulting, we have investigated the possible presence of IGF-I and melatonin receptors on the dermis and hair follicles of cashmere and Angora goats, sampled in February, March and June, using quantitative in vitro autoradiography. The presence of IGF-I receptors in the dermis of both breeds of goat was determined using cryostat sections incubated with 50 pm 125I-labelled IGF-I in the presence or absence of 50 nm IGF-I. Sections of the growing tip of deer antlers containing the cartilaginous zone, a tissue known to contain high concentrations of specific IGF-I receptors, were used as a positive control. As the production of antler velvet uniquely involves the generation of hair follicles de novo, the presence of IGF-I receptors in the velvet-producing region was also investigated. In both breeds of goat, specific 125I-IGF-I binding was localised over the inner and outer root sheath, the matrix, the germinal matrix, the dermal papilla and the sebaceous glands and satisfied the basic kinetic criteria considered to be representative of a specific IGF-I receptor. Analysis of saturation isotherms using a one-site binding model revealed dissociation constants (Kd) in the range 0·1–0·9 nm and theoretical maximal numbers of binding sites (Bmax) between 21·4 and 45·6 fmol/mg tissue. Kd and Bmax values derived from cashmere and Angora goats sampled at different times of the year did not differ significantly between breeds or sampling times. Specific 125I-IGF-I binding was also localised to the developing follicles on the deer antler dermis. The presence of melatonin receptors within the goat dermis was also investigated. Sections were incubated with 100 pm 2-[125I]iodomelatonin with or without 0·1 μm melatonin, along with sections of sheep pars tuberalis which are known to contain high levels of high-affinity melatonin receptors. No displaceable 2-[125I]iodomelatonin binding was found on any sections of the cashmere or Angora skin analysed. It is therefore concluded that melatonin receptors are not present on the hair follicles or associated structures. IGF-I receptors are present on the hair follicle and sebaceous gland and may be involved in the growth of both seasonally and non-seasonally produced fibre and in the development of antler velvet. Journal of Endocrinology (1996) 151, 55–63

Melatonin-binding sites in the rat brain and pituitary mapped by in-vitro autoradiography

1989 ◽  
Vol 3 (1) ◽  
pp. 71-75 ◽  
Author(s):  
L. M. Williams
Keyword(s):  
Rat Brain ◽  
Binding Sites ◽  
Area Postrema ◽  
Specific Binding ◽  
Melatonin Receptors ◽  
Pars Tuberalis ◽  
Lower Affinity ◽  
High Affinity ◽  
In Vitro Autoradiography

ABSTRACT Using picomolar concentrations of [125I]iodomelatonin and in-vitro autoradiography, specific melatonin-binding sites have been mapped in the rat brain and pituitary. Using this same technique, high-affinity melatonin receptors had previously been identified in the suprachiasmatic nucleus (SCN) and median eminence regions of the rat hypothalamus. The presence of melatonin binding in the SCN has been confirmed, but the second area of binding has been identified as the pars tuberalis of the pituitary, and a completely novel area of binding is also reported in the area postrema. The existence of lower affinity melatonin receptors in the rat brain was also investigated using in-vitro autoradiography and higher concentrations of [125I]iodomelatonin. No further sites of specific binding were, however, disclosed.

In Vitro Lh Release from the Hypothalamus-Pars Tuberalis; Effects of Gonadotropin-Releasing Hormone (GnRH), $rH-Endorphin and Biogenic Amines

1987 ◽  
Vol 13 (3) ◽  
pp. 251-266 ◽  
Author(s):  
Nicholas V. Emanuele ◽  
Lynn Wallock ◽  
Georgiann Baker ◽  
David Kostka ◽  
Lidia Kirsteins ◽  
...  
Keyword(s):  
Biogenic Amines ◽  
Gonadotropin Releasing Hormone ◽  
Pars Tuberalis ◽  
Releasing Hormone ◽  
Lh Release

Einfluß der Glucose auf die [14C] Thymidin-Einbaurate von Ehrlich-Ascitescarcinomzellen in vitro

1969 ◽  
Vol 08 (02) ◽  
pp. 196-206 ◽  
Author(s):  
Dieter. Kummer
Keyword(s):  
De Novo

ZusammenfassungIn nahezu glucosefreier Suspension von Ehrlich-Ascitescarcinomzellen bewirkt die Zufuhr von Glucose 2,5 × 10–4 bis 10–2 M:1. Hemmung der [14C] Thymidin-Einbaurate in die Zellen.2. Aktivierung des Ribonucleotid-Reductase-Systems und damit Stimulierung der Desoxyribonucleotidsynthese (auch der Thymidintriphosphat-de-novo-Synthese).3. Blockierung der Thymidinkinase über Endprodukthemmung, wodurch die Minderung des [14C] Thymidin-Einbaus in die Zellen erklärbar ist.

Особенности морфогенеза редкого вида Allium neriniflorum (Herb.) Backer в условиях in vitro

2019 ◽  
pp. 37-41 ◽  
Author(s):  
Альбина Шамсуновна Ахметова ◽  
Альфия Ануровна Зарипова
Keyword(s):  
De Novo

Показана возможность эффективного применения метода культуры тканей для размножения Allium neriniflorum (Herb.) Backer. Исследуемый вид является декоративным растением, размножение которого затруднено из-за низкой всхожести семян и ослабленной способности к формированию дочерних луковиц. Разработана технология клонального микроразмножения из стерильных луковиц. В качестве исходного материала использовали семена A. neriniflorum. Подобраны условия стерилизации, позволяющие достичь максимального числа (75 %) жизнеспособных эксплантов. Поверхностную стерилизацию проводили в ламинар-боксе с использованием в качестве стерилизующего агента 0,1 % раствор диацида. Семена сначала обрабатывали 70 % этанолом, затем стерилизующим раствором. Экспозиция стерилизующих растворов составляла от 5 до 9 мин. Показано, что способность к индуцированному морфогенезу существенно зависит от состава питательной среды. Максимальное число луковиц образовывалось на среде QL — 9 шт./эксплант. Исследуемые виды обладали высокой способностью к мультипликации и формированию полноценных растений при подобранных условиях культивирования in vitro. Выявленная морфогенетическая активность зачаточного побега, сегментов чешуй и донца стерильной луковицы A. neriniflorum, проявляющаяся в способности регенерировать побеги de novo, что возможно только в культуре in vitro, обеспечивает формирование полноценных луковиц. Луковицы, полученные in vitro, включали в последующие циклы микроразмножения. Культура тканей и органов in vitro позволяет размножать A. neriniflorum с более высоким коэффициентом размножения. От одной стерильной луковицы можно получить до 7000 луковиц в год. При традиционном вегетативном способе размножения материнская луковица формирует 1, редко 2 дочерние луковицы.

Study of Phosphocalcic Glasses from SiO2-CaO-P2O5 System with and Without Silver II. The bioactivity analysis by FTIR, SEM methods and microbiological study of silver-doped glasses

2017 ◽  
Vol 68 (6) ◽  
pp. 1188-1192
Author(s):  
Daniela Avram ◽  
Nicolae Angelescu ◽  
Dan Nicolae Ungureanu ◽  
Ionica Ionita ◽  
Iulian Bancuta ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Body Fluid ◽  
Pathogenic Bacteria ◽  
De Novo ◽  
Microbiological Examination ◽  
Doped Glasses ◽  
P2o5 System ◽  
Scanning Electron

The study in vitro of the glass powders bioactivity was performed by soaking them in simulated body fluid for 3 to 21 days at a temperature of 37�C and pH = 7.20. The synthesis de novo of hydroxyapatite, post soaking was confirmed by Fourier Transform Infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The study of the antimicrobial activity was performed by microbiological examination on two strains of pathogenic bacteria involved in postoperative nosocomial infections.

N-Acetylserotonin vs Melatonin: In-Vitro Controlled Release from Hydrophilic Matrix Tablets

2019 ◽  
Vol 16 (3) ◽  
pp. 347-352 ◽  
Author(s):  
M. Vlachou ◽  
G. Stavrou ◽  
A. Siamidi ◽  
S. Flitouri ◽  
V. Ioannidou ◽  
...  
Keyword(s):  
Controlled Release ◽  
Selective Serotonin Reuptake Inhibitors ◽  
Sleep Onset ◽  
Matrix Tablets ◽  
Melatonin Receptors ◽  
Solid Matrix ◽  
Poor Sleep ◽  
Prolonged Release ◽  
Hydrophilic Matrix

Background: N-Acetylserotonin (NAS, N-acetyl-5-hydroxytryptamine) is the immediate precursor of the neurohormone melatonin (MT, N-acetyl-5-methoxytryptamine), which regulates sleep and wake cycles. NAS is produced by the N-acetylation of serotonin and is converted to melatonin via the action of Acetylserotonin O-methyltransferase (ASMT). Like melatonin, NAS acts as an agonist on the melatonin receptors MT1, MT2, and MT3. However, as NAS is abundant in specific brain areas, separate from serotonin and melatonin, it may also have discrete central effects. Indicatively, it has been reported that NAS may play a role in the antidepressant effects of Selective Serotonin Reuptake Inhibitors (SSRIs) and Monoamine Oxidase Inhibitors (MAOIs). </P><P> Objective: To decipher the controlled release characteristics of the active substances (NAS and MT) in a quick initial pace, aiming at a satisfactory sleep-onset related anti-depressive profile and prolonged release, thereafter, targeting at coping with poor sleep quality problems. </P><P> Methods: A series of hydrophilic matrix tablets involving as excipients, hydroxypropylmethylcellulose (HPMC) K15M, low viscosity sodium alginate, lactose monohydrate, and polyvinylpyrrolidone (PVP) M.W.: 10.000 and 55.000) was developed and tested at two dissolution media (pH 1.2 and 7.4). </P><P> Results: The results showed that commonly used excipients with different physicochemical properties govern the controlled release of NAS and MT from solid matrix systems. </P><P> Conclusions: We have demonstrated how broadly used excipients affect the in vitro controlled release of NAS and MT from solid pharmaceutical formulations. Currently, we extend our studies on the controlled release of these drugs using various other biopolymers/formulants of different physicochemical characteristics, which will help to highlight the discrete release profiles of NAS and MT.

scholarly journals Stereotypic neutralizing VH antibodies against SARS-CoV-2 spike protein receptor binding domain in COVID-19 patients and healthy individuals

2021 ◽  
pp. eabd6990
Author(s):  
Sang Il Kim ◽  
Jinsung Noh ◽  
Sujeong Kim ◽  
Younggeun Choi ◽  
Duck Kyun Yoo ◽  
...  
Keyword(s):  
B Cells ◽  
Receptor Binding ◽  
Neutralizing Antibodies ◽  
De Novo ◽  
Binding Domain ◽  
Host Cells ◽  
Spike Protein ◽  
Receptor Binding Domain ◽  
Healthy Individuals

Stereotypic antibody clonotypes exist in healthy individuals and may provide protective immunity against viral infections by neutralization. We observed that 13 out of 17 patients with COVID-19 had stereotypic variable heavy chain (VH) antibody clonotypes directed against the receptor-binding domain (RBD) of SARS-CoV-2 spike protein. These antibody clonotypes were comprised of immunoglobulin heavy variable (IGHV)3-53 or IGHV3-66 and immunoglobulin heavy joining (IGHJ)6 genes. These clonotypes included IgM, IgG3, IgG1, IgA1, IgG2, and IgA2 subtypes and had minimal somatic mutations, which suggested swift class switching after SARS-CoV-2 infection. The different immunoglobulin heavy variable chains were paired with diverse light chains resulting in binding to the RBD of SARS-CoV-2 spike protein. Human antibodies specific for the RBD can neutralize SARS-CoV-2 by inhibiting entry into host cells. We observed that one of these stereotypic neutralizing antibodies could inhibit viral replication in vitro using a clinical isolate of SARS-CoV-2. We also found that these VH clonotypes existed in six out of 10 healthy individuals, with IgM isotypes predominating. These findings suggest that stereotypic clonotypes can develop de novo from naïve B cells and not from memory B cells established from prior exposure to similar viruses. The expeditious and stereotypic expansion of these clonotypes may have occurred in patients infected with SARS-CoV-2 because they were already present.

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