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1.
Artigo em Espanhol | LILACS, CUMED | ID: biblio-1536334

RESUMO

Introducción: La asertividad es una herramienta comunicacional que puede contribuir de manera positiva en que los adultos mayores interpreten correctamente la necesidad e importancia de realizar acciones que permitan mantener un adecuado desarrollo físico y estado nutricional durante la tercera edad. Objetivo: Describir cómo la implementación de la comunicación asertiva puede ayudar a la incorporación de los adultos mayores al programa de actividades físicas del adulto mayor. Métodos: Se realizó una investigación básica, no experimental y descriptiva en una población de 157 adultos mayores, de los cuales 113 formaron parte de la muestra de investigación. Se aplicó la comunicación asertiva para lograr la incorporación de estos al programa de actividades físicas del adulto mayor. Resultados: El miedo al contagio con COVID-19 fue la principal causa referida para no participar en las actividades (17,70 por ciento). Predominaron los adultos mayores con nivel de conocimiento bajo sobre la importancia de las actividades físicas en los adultos mayores. Después de aplicar la comunicación asertiva se logró que el 64,60 por ciento de los ancianos se incorporaran al programa. Conclusiones: La asertividad, con sus técnicas y acciones, facilitó la incorporación de adultos mayores al programa de actividades físicas. Su aplicación se basó en la preparación y la capacidad de negociación con las personas de la tercera edad para poder lograr su incorporación a las actividades físicas del programa del adulto mayor(AU)


Introduction: Assertiveness is a communicational tool that can contribute positively to aged adults' correct interpretation of the need and importance of performing actions that allow them to maintain adequate physical development and nutritional status during older age. Objective: To describe how the implementation of assertive communication can help the incorporation of aged adults to the physical activity program for the elderly. Methods: A basic, nonexperimental and descriptive research was conducted with a population of 157 aged adults, of which 113 were part of the research sample. Assertive communication was applied to achieve their incorporation into the physical activity program for the elderly. Results: Fear of infection with COVID-19 was the main reported cause for not participating in the activities (17.70 percent). Aged adults with a low level of knowledge about the importance of physical activities for the elderly predominated. After applying assertive communication, 64.60 percent of the older adults could become part of the program. Conclusions: Assertiveness, with its techniques and actions, facilitated the incorporation of aged adults to the physical activities program. Its application was based on the preparation and the ability to negotiate with older adults in order to achieve their incorporation to the physical activities of the program for the elderly(AU)


Assuntos
Humanos , Masculino , Feminino , Assertividade , Exercício Físico/fisiologia , Comunicação , Nutrição do Idoso , Epidemiologia Descritiva
2.
Animal ; 17 Suppl 1: 100754, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-37567661

RESUMO

The actions of the beta-nerve growth factor (ß-NGF) on the neuroendocrine and reproductive system have challenged classical views on the control of reproductive function. After endometrial absorption, ß-NGF triggers ovulation and promotes the development of functional corpora lutea in camelids. In this article, we review evidence showing that, in camelids, ß-NGF exerts its actions by acting in both the hypothalamus and the ovary. In the hypothalamus, ß-NGF may induce gonadotropin-releasing hormone (GnRH) release by interacting with neurons or glial cells expressing receptors for ß-NGF. The LH surge occurs under the influence of ovarian estradiol and requires the release of GnRH into the portal vessels to reach the pituitary gland. In the ovary, ß-NGF may be promoting the differentiation of follicular to luteal cells by modifying the steroidogenic profile of ovarian follicular cells in both camelids and ruminants. Although the mechanisms for these actions are largely undetermined, we aim to offer an update on the current understanding of the effects of ß-NGF controlling reproductive function in camelids and ruminants.

3.
Endocrinology ; 164(10)2023 08 28.
Artigo em Inglês | MEDLINE | ID: mdl-37586095

RESUMO

Allostasis provides a supporting role to the homeostatic control of biological variables in mammalian species. While the concept of homeostasis is related to the control of variables within a set point or range that are essential to life, allostasis refers to systems that facilitate adaptation to challenges that the organism faces and the new requirements for survival. Essential for such adaptation is the role played by the brain in eliciting neural and neuroendocrine responses. Reproductive function is fundamental for the survival of species but is costly in energetic terms and requires a synchrony with an ever-changing environment. Thus, in many species reproductive function is blocked or delayed over immediate challenges. This review will cover the physiological systems and neuroendocrine pathways that supply allostatic control over reproductive neuroendocrine systems. Light, hypoxia, temperature, nutrition, psychosocial, and immune mediators influence the neuroendocrine control of reproductive functions through pathways that are confluent at the paraventricular nucleus; however, understanding of the integrative responses to these stimuli has not been clarified. Likely, the ultimate consequence of these allostatic mechanisms is the modification of kisspeptin and gonadotropin-releasing hormone neuronal activity, thus compromising reproduction function in the short term, while preserving species survivability.


Assuntos
Alostase , Animais , Alostase/fisiologia , Reprodução/fisiologia , Adaptação Fisiológica/fisiologia , Sistemas Neurossecretores , Hormônio Liberador de Gonadotropina , Mamíferos
4.
JACC CardioOncol ; 5(3): 318-328, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37397088

RESUMO

Background: Sodium glucose cotransporter-2 inhibitors (SGLT2is) are hypothesized to reduce the risk of anthracycline-associated cardiotoxicity. Objectives: This study sought to determine the association between SGLT2is and cardiovascular disease (CVD) after anthracycline-containing chemotherapy. Methods: Using administrative data sets, we conducted a population-based cohort study of people >65 years of age with treated diabetes and no prior heart failure (HF) who received anthracyclines between January 1, 2016, and December 31, 2019. After estimating propensity scores for SGLT2i use, the average treatment effects for the treated weights were used to reduce baseline differences between SGLT2i-exposed and -unexposed controls. The outcomes were hospitalization for HF, incident HF diagnoses (in- or out-of-hospital), and documentation of any CVD in future hospitalizations. Death was treated as a competing risk. Cause-specific HRs for each outcome were determined for SGLT2i-treated people relative to unexposed controls. Results: We studied 933 patients (median age 71.0 years, 62.2% female), 99 of whom were SGLT2i treated. During a median follow-up of 1.6 years, there were 31 hospitalizations for HF (0 in the SGLT2i group), 93 new HF diagnoses, and 74 hospitalizations with documented CVD. Relative to controls, SGLT2i exposure was associated with HR of 0 for HF hospitalization (P < 0.001) but no significant difference in incident HF diagnosis (HR: 0.55; 95% CI: 0.23-1.31; P = 0.18) or CVD diagnosis (HR: 0.39; 95% CI: 0.12-1.28; P = 0.12). There was no significant difference in mortality (HR: 0.63; 95% CI: 0.36-1.11; P = 0.11). Conclusions: SGLT2is may reduce the rate of HF hospitalization after anthracycline-containing chemotherapy. This hypothesis warrants further testing in randomized controlled trials.

5.
Int J Mol Sci ; 24(11)2023 May 26.
Artigo em Inglês | MEDLINE | ID: mdl-37298236

RESUMO

Despite not dividing, senescent cells acquire the ability to synthesize and secrete a plethora of bioactive molecules, a feature known as the senescence-associated secretory phenotype (SASP). In addition, senescent cells often upregulate autophagy, a catalytic process that improves cell viability in stress-challenged cells. Notably, this "senescence-related autophagy" can provide free amino acids for the activation of mTORC1 and the synthesis of SASP components. However, little is known about the functional status of mTORC1 in models of senescence induced by CDK4/6 inhibitors (e.g., Palbociclib), or the effects that the inhibition of mTORC1 or the combined inhibition of mTORC1 and autophagy have on senescence and the SASP. Herein, we examined the effects of mTORC1 inhibition, with or without concomitant autophagy inhibition, on Palbociclib-driven senescent AGS and MCF-7 cells. We also assessed the pro-tumorigenic effects of conditioned media from Palbociclib-driven senescent cells with the inhibition of mTORC1, or with the combined inhibition of mTORC1 and autophagy. We found that Palbociclib-driven senescent cells display a partially reduced activity of mTORC1 accompanied by increased levels of autophagy. Interestingly, further mTORC1 inhibition exacerbated the senescent phenotype, a phenomenon that was reversed upon autophagy inhibition. Finally, the SASP varied upon inhibiting mTORC1, or upon the combined inhibition of mTORC1 and autophagy, generating diverse responses in cell proliferation, invasion, and migration of non-senescent tumorigenic cells. Overall, variations in the SASP of Palbociclib-driven senescent cells with the concomitant inhibition of mTORC1 seem to depend on autophagy.


Assuntos
Senescência Celular , Piperazinas , Humanos , Alvo Mecanístico do Complexo 1 de Rapamicina/metabolismo , Piperazinas/farmacologia , Carcinogênese , Autofagia
6.
Reproduction ; 165(4): 395-405, 2023 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-36757313

RESUMO

In brief: Seminal nerve growth factor induces ovulation in camelids by influencing the secretion of gonadotrophin-releasing hormone (GnRH) into the portal vessels of the pituitary gland. We show that the nerve growth factor-induced release of GnRH is not mediated directly through interaction with hypothalamic neurons. Abstract: Ovulation in camelids is triggered by seminal nerve growth factor (NGF). The mechanism of action of NGF appears to occur via the central nervous system. In this study, we tested the hypothesis that NGF acts in the hypothalamus to induce GnRH release. To determine if NGF-induced ovulation is associated with a rise in NGF concentrations in the cerebrospinal fluid (CSF), llamas were i) mated with an urethrostomized male, ii) mated with intact male, or given intrauterine iii) seminal plasma or i.v.) saline (Experiment 1). To characterize the luteinizing hormone (LH) response after central vs peripheral administration, llamas were treated with saline (negative control) or NGF either by i.v. or intracerebroventricular (ICV) administration (Experiment 2). To determine the role of kisspeptin, the effect of ICV infusion of a kisspeptin receptor antagonist on NGF-induced LH secretion and ovulation was tested in llamas (Experiment 3). In Experiment 1, a surge in circulating concentrations of LH was detected only in llamas mated with an intact male and those given intrauterine seminal plasma, but no changes in CSF concentrations of NGF were detected. In Experiment 2, peripheral administration (i.v.) of NGF induced an LH surge and ovulation, whereas no response was detected after central (ICV) administration. In Experiment 3, the kisspeptin receptor antagonist had no effect on the LH response to NGF. In conclusion, results did not support the hypothesis that NGF-induced ovulation is mediated via a trans-synaptic pathway within the hypothalamus, but rather through a releasing effect on tanycytes at the median eminence.


Assuntos
Camelídeos Americanos , Fator de Crescimento Neural , Feminino , Animais , Masculino , Fator de Crescimento Neural/farmacologia , Progesterona , Camelídeos Americanos/metabolismo , Kisspeptinas/farmacologia , Kisspeptinas/metabolismo , Hormônio Luteinizante/metabolismo , Hormônio Liberador de Gonadotropina/metabolismo , Hipotálamo/metabolismo
7.
Acta Physiol (Oxf) ; 237(4): e13940, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-36700365

RESUMO

The prevalence of gestational diabetes mellitus (GDM) has increased in recent years, along with the higher prevalence of obesity in women of reproductive age. GDM is a pathology associated with vascular dysfunction in the fetoplacental unit. GDM-associated endothelial dysfunction alters the transfer of nutrients to the foetus affecting newborns and pregnant women. Various mechanisms for this vascular dysfunction have been proposed, of which the most studied are metabolic alterations of the vascular endothelium. However, different cell types are involved in GDM-associated endothelial dysfunction, including platelets. Platelets are small, enucleated cell fragments that actively take part in blood haemostasis and thrombus formation. Thus, they play crucial roles in pathologies coursing with endothelial dysfunction, such as atherosclerosis, cardiovascular diseases, and diabetes mellitus. Nevertheless, platelet function in GDM is understudied. Several reports show a potential relationship between platelet volume and mass with GDM; however, platelet roles and signaling mechanisms in GDM-associated endothelial dysfunction are unclear. This review summarizes the reported findings and proposes a link among altered amount, volume, mass, reactivity, and function of platelets and placenta development, resulting in fetoplacental vascular dysfunction in GDM.


Assuntos
Diabetes Gestacional , Doenças Vasculares , Gravidez , Feminino , Recém-Nascido , Humanos , Diabetes Gestacional/metabolismo , Diabetes Gestacional/patologia , Placenta/metabolismo , Plaquetas/metabolismo , Endotélio Vascular/metabolismo , Doenças Vasculares/metabolismo
8.
Reprod Domest Anim ; 58(3): 459-464, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36385721

RESUMO

Hormonally active tumours are characterized by production and secretion of hormones, irrespective of endogenous feedback mechanisms. An adult llama had exuberant oestrous behaviour, infertility, elevated concentrations of oestradiol and a large ovarian mass. Necropsy revealed the presence of two large abdominal masses, one effacing the right ovary and one in the mesocolon. Considering the clinical and histopathological findings, we conclude that the llama was affected by a granulosa cell tumour. The case suggests that granulosa cell tumours in camelids are hormonally active, and the clinical presentation resembles that of other large animal species. To our knowledge, this is the first case report of an oestrogen-producing, metastatic granulosa cell tumour in a llama.


Assuntos
Camelídeos Americanos , Tumor de Células da Granulosa , Neoplasias Ovarianas , Feminino , Animais , Tumor de Células da Granulosa/veterinária , Neoplasias Ovarianas/veterinária
9.
PLoS One ; 17(12): e0278564, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36459509

RESUMO

Kisspeptin modulates GnRH secretion in mammals and peripheral administration of 10-amino acid fragment of kisspeptin (Kp10) induces LH release and ovulation in cattle. Experiments were done to determine if iv administration of kisspeptin will activate GnRH neurons (i.e., after crossing the blood-brain barrier) and if pre-treatment with a GnRH receptor blocker will alter kisspeptin-induced LH release (from gonadotrophs) and ovulation. In Experiment 1, cows (n = 3 per group) were given human-Kisspeptin10 (hKp10; 3 x 15 mg iv at 60-min intervals) or normal saline and euthanized 150 min after treatment was initiated. Every 20th free-floating section (50 µm thickness) from the preoptic area to hypothalamus was double immunostained to colocalize GnRH- (DAB) and activated neurons (cFOS; Nickel-DAB). Kisspeptin induced plasma LH release from 15 to 150 min (P = 0.01) but the proportion of activated GnRH neurons did not differ between groups (5.8% and 3.5%, respectively; P = 0.11). Immunogold electron microscopy detected close contacts between kisspeptin fibers and GnRH terminals in the median eminence. In Experiment 2, pubertal heifers (n = 5 per group) were treated with 1) hKp10 iv, 2) Cetrorelix (GnRH antagonist; im) + hKp10 iv or 3) saline on Day 6 of the follicular wave under low-progesterone condition. A rise in plasma LH concentration was detected from 15 to 240 min in the hKp10 group but not in cetrorelix or control group (P<0.001). Ovulations were detected only in the hKp10 group (4/5; P = 0.02). Cetrorelix treatment was associated with regression of the preovulatory dominant follicle and emergence of a new follicular wave 3.4±0.75 days after the treatment in all five heifers. Results support the hypothesis that the effect of peripheral kisspeptin is mediated downstream of GnRH synthesis and does not involve GnRH-independent LH release from gonadotrophs. Peripheral kisspeptin may release pre-synthesized GnRH from the nerve terminals in areas outside the blood-brain barrier.


Assuntos
Gonadotrofos , Kisspeptinas , Humanos , Bovinos , Animais , Feminino , Kisspeptinas/farmacologia , Hormônio Liberador de Gonadotropina , Ovulação , Área Pré-Óptica , Mamíferos
11.
Rev. med. Chile ; 150(9): 1260-1265, sept. 2022. ilus
Artigo em Espanhol | LILACS | ID: biblio-1431894

RESUMO

Hereditary transthyretin amyloidosis is a multisystemic autosomal dominant genetic disorder characterized by progressive distal sensory-motor polyneuropathy or restrictive cardiomyopathy, secondary to amyloid deposits. Its pathogenesis lies in the TTR gene mutation, and the Val50Met mutation is the most frequent. Patients have significant differences in the onset and severity of clinical presentation according to their country of origin. The diagnosis of this pathology is complex, even more in countries where it is not considered endemic. However, early suspicion and management are essential to improve survival and avoid unnecessary diagnostic and therapeutic strategies. We report a 69-year-old woman who presented a sensory-motor polyneuropathy, predominantly sensory, associated with distal neuropathic pain and bilateral vitritis. The history of her Italian father with polyneuropathy of unspecified etiology stood out. A vitreous biopsy identified amyloid substance deposits (congo red positive). These were also confirmed on a superficial peroneal nerve biopsy. During the etiological study of her polyneuropathy, an increased Kappa/Lambda index of 2.55 mg/L stood out. Therefore, light chain amyloidosis was suspected, and chemotherapy treatment was indicated without favorable response. After 10 years of progressive neurological and ophthalmological involvement, a genetic study confirmed the first case of late-onset hereditary transthyretin amyloidosis Val50Met with polyneuropathy in Chile.


Assuntos
Humanos , Feminino , Idoso , Polineuropatias/etiologia , Polineuropatias/genética , Neuropatias Amiloides Familiares/complicações , Neuropatias Amiloides Familiares/diagnóstico , Neuropatias Amiloides Familiares/genética , Pré-Albumina/genética , Mutação
13.
Neurosurg Rev ; 45(5): 3361-3379, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-35982344

RESUMO

This study describes and characterizes a narrow, hollow tubular structure, termed as duct-like diverticulum (DV), found specifically at the basal midline of papillary craniopharyngiomas (PCPs) located within the third ventricle (3V). The presence of this structure was systematically investigated on autopsy studies and magnetic resonance imaging (MRI) scans of 3536 craniopharyngioma (CP) cases published in the medical literature from 1911 to 2021, as well as in other twelve 3V tumor categories (n = 1470 cases). A basal DV was observed in a total of 50 PCPs, including two of our own cases. This DV corresponds to a tubular-shaped recess invaginated at the midline bottom of the tumor, following the same angled trajectory as the pituitary stalk. It can be easily seen as a hypointense linear structure on T1- and T2-weighted MRI scans, with two main length types: long DVs (74%), which reach the tumor center, and short DVs (26%), which penetrate the tumor only a few millimeters. The DV sign identifies the papillary CP type with a specificity of 100% and a sensitivity of 33% in the overall CP population. This finding also serves to establish the strictly intra-3V location of the lesion with a 95% specificity and 42% sensitivity among papillary CPs. No similar basal DV was found in adamantinomatous CPs nor among other categories of strictly 3V tumors. Consequently, the presence of a diverticulum in a 3V tumor represents a morphological signature pathognomonic of the papillary type and a valuable sign to reliably define the strictly 3V topography.


Assuntos
Craniofaringioma , Divertículo , Neoplasias Hipofisárias , Terceiro Ventrículo , Craniofaringioma/diagnóstico por imagem , Craniofaringioma/cirurgia , Divertículo/diagnóstico por imagem , Divertículo/cirurgia , Humanos , Hipófise , Neoplasias Hipofisárias/diagnóstico por imagem , Neoplasias Hipofisárias/cirurgia , Terceiro Ventrículo/diagnóstico por imagem , Terceiro Ventrículo/patologia , Terceiro Ventrículo/cirurgia
15.
Sensors (Basel) ; 22(14)2022 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-35891001

RESUMO

The prognostics and health management disciplines provide an efficient solution to improve a system's durability, taking advantage of its lifespan in functionality before a failure appears. Prognostics are performed to estimate the system or subsystem's remaining useful life (RUL). This estimation can be used as a supply in decision-making within maintenance plans and procedures. This work focuses on prognostics by developing a recurrent neural network and a forecasting method called Prophet to measure the performance quality in RUL estimation. We apply this approach to degradation signals, which do not need to be monotonical. Finally, we test our system using data from new generation telescopes in real-world applications.


Assuntos
Análise de Falha de Equipamento , Redes Neurais de Computação , Análise de Falha de Equipamento/métodos
16.
J Neuropathol Exp Neurol ; 81(5): 330-343, 2022 04 27.
Artigo em Inglês | MEDLINE | ID: mdl-35472085

RESUMO

This study investigates the presence of a hollow recess at the midline undersurface of tumors primarily localized within the third ventricle (3V). This structure was originally identified by magnetic resonance imaging (MRI) of 6 3V craniopharyngiomas (CPs) from our series and was then methodically scrutinized in autopsy studies (n = 1091) and MRI scans (n = 5558) of CPs and in 1251 3V tumors reported in the medical literature from 1839 to 2021. A recess at the tumor base was identified in 110 CPs, 95 with a verified papillary histology (papillary craniopharyngioma [PCP]) and 15 with typical gross appearance of PCP. Topographically, 90 tumors were strictly within the 3V (82%); 20 developed at the infundibulo-tuberal region of the 3V floor (18%). Morphologically, 2 main types of recess were identified: (i) a long, narrow recess with either a duct-like or a tubular shape that reached the central region of the CP (n = 47, 42.5%); and (ii) a short recess extending only a few millimeters into the lesion, either with a duct-like or a shallow cleft-like morphology (n = 63, 57.5%). Thus, the presence of a basal recess represents a pathological hallmark of a subpopulation of 3V PCPs. The presumed nature and diagnostic significance of this novel finding is comprehensively addressed.


Assuntos
Craniofaringioma , Neoplasias Hipofisárias , Terceiro Ventrículo , Craniofaringioma/diagnóstico por imagem , Craniofaringioma/patologia , Humanos , Imageamento por Ressonância Magnética , Neoplasias Hipofisárias/diagnóstico por imagem , Neoplasias Hipofisárias/patologia , Terceiro Ventrículo/diagnóstico por imagem , Terceiro Ventrículo/patologia
18.
Cells ; 11(6)2022 03 17.
Artigo em Inglês | MEDLINE | ID: mdl-35326465

RESUMO

Platelets play important roles in thrombosis-dependent obstructive cardiovascular diseases. In addition, it has now become evident that platelets also participate in the earliest stages of atherosclerosis, including the genesis of the atherosclerotic lesion. Moreover, while the link between platelet activity and hemostasis has been well established, the role of platelets as modulators of inflammation has only recently been recognized. Thus, through their secretory activities, platelets can chemically attract a diverse repertoire of cells to inflammatory foci. Although monocytes and lymphocytes act as key cells in the progression of an inflammatory event and play a central role in plaque formation and progression, there is also evidence that platelets can traverse the endothelium, and therefore be a direct mediator in the progression of atherosclerotic plaque. This review provides an overview of platelet interactions and regulation in atherosclerosis.


Assuntos
Aterosclerose , Trombose , Aterosclerose/patologia , Plaquetas/patologia , Hemostasia , Humanos , Inflamação/patologia
19.
Rev Med Chil ; 150(9): 1260-1265, 2022 Sep.
Artigo em Espanhol | MEDLINE | ID: mdl-37358138

RESUMO

Hereditary transthyretin amyloidosis is a multisystemic autosomal dominant genetic disorder characterized by progressive distal sensory-motor polyneuropathy or restrictive cardiomyopathy, secondary to amyloid deposits. Its pathogenesis lies in the TTR gene mutation, and the Val50Met mutation is the most frequent. Patients have significant differences in the onset and severity of clinical presentation according to their country of origin. The diagnosis of this pathology is complex, even more in countries where it is not considered endemic. However, early suspicion and management are essential to improve survival and avoid unnecessary diagnostic and therapeutic strategies. We report a 69-year-old woman who presented a sensory-motor polyneuropathy, predominantly sensory, associated with distal neuropathic pain and bilateral vitritis. The history of her Italian father with polyneuropathy of unspecified etiology stood out. A vitreous biopsy identified amyloid substance deposits (congo red positive). These were also confirmed on a superficial peroneal nerve biopsy. During the etiological study of her polyneuropathy, an increased Kappa/Lambda index of 2.55 mg/L stood out. Therefore, light chain amyloidosis was suspected, and chemotherapy treatment was indicated without favorable response. After 10 years of progressive neurological and ophthalmological involvement, a genetic study confirmed the first case of late-onset hereditary transthyretin amyloidosis Val50Met with polyneuropathy in Chile.


Assuntos
Neuropatias Amiloides Familiares , Polineuropatias , Humanos , Feminino , Idoso , Pré-Albumina/genética , Neuropatias Amiloides Familiares/complicações , Neuropatias Amiloides Familiares/diagnóstico , Neuropatias Amiloides Familiares/genética , Mutação , Polineuropatias/etiologia , Polineuropatias/genética
20.
Anim Reprod ; 19(4): e20220116, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36819481

RESUMO

The ovulation mechanism is one of the fascinating physiological processes in reproductive biology in mammals. From the reproductive point of view, the species have been classified as spontaneous or induced ovulators. Although the release of GnRH followed by the preovulatory LH surge is shared between both types of ovulation, the stimulus to initiate GnRH release varies between both categories. In spontaneous ovulators, ovulation depends on the systemic concentration of ovarian steroids, however, in induced ovulators, different stimuli such as copulation, environmental, and social cues can facilitate or induce ovulation regardless of the increases in systemic estradiol concentration. In this review, we document evidence that a male-derived protein is the main factor responsible for inducing ovulation and also modulating the ovarian function in the domestic South American camelid, the llama. The neurotrophin beta-Nerve Growth Factor (ß-NGF) is the principal factor present in the semen of llamas responsible for inducing ovulation in this species. After the intrauterine deposit of semen during mating, ß-NGF is absorbed through the endometrium to reach the circulatory system, where it reaches the hypothalamus and stimulates GnRH release. The potential site of action of this neurotrophin at the brain has not been elucidated, however, hypotheses are raised that the factor may cross the blood-brain barrier and stimulate upstream neuronal networks that lead to the stimulation of GnRH-secreting neurons. It is possible that ß-NGF could be sensed at the median eminence without crossing the blood-brain barrier. Finally, it has been observed that this factor is not only a powerful stimulator of ovulation but also has a luteotrophic effect, resulting in the development of a corpus luteum capable of secreting more progesterone when compared to other ovulation-stimulating analogues.

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