Structure and Function of the Normal Testis and Epididymis

The structure and function of the testis and epididymis are described, emphasizing the general similarities and specific differences between various species and humans. Current concepts of spermatogenesis are reviewed and the developmental stages of the germinal epithelium are discussed, as well as the complex hormonal interactions that take place. It is crucial to recognize that the efficiency of sperm production and the epididymal reserves in the human are considerably lower than those of conventional animal models. Therefore, the human male is more susceptible to a decline in fertility caused by a specific decrement in spermatogenesis than is an animal model.

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Cardiac structure and function in animal models and in human hypertension

The Heart in Hypertension - Developments in Cardiovascular Medicine ◽

10.1007/978-94-009-0941-0_14 ◽

1989 ◽

pp. 145-164 ◽

Cited By ~ 3

Author(s):

P. I. Korner

Keyword(s):

Animal Models ◽

Structure And Function ◽

Cardiac Structure ◽

Human Hypertension ◽

Cardiac Structure And Function ◽

And Function

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Plant Histone HTB (H2B) Variants in Regulating Chromatin Structure and Function

Plants ◽

10.3390/plants9111435 ◽

2020 ◽

Vol 9 (11) ◽

pp. 1435

Author(s):

Janardan Khadka ◽

Anat Pesok ◽

Gideon Grafi

Keyword(s):

Arabidopsis Thaliana ◽

Chromatin Structure ◽

Developmental Stages ◽

Histone Variants ◽

Structure And Function ◽

Core Histone ◽

Histone H2b ◽

Histone Proteins ◽

Genes Encoding ◽

And Function

Besides chemical modification of histone proteins, chromatin dynamics can be modulated by histone variants. Most organisms possess multiple genes encoding for core histone proteins, which are highly similar in amino acid sequence. The Arabidopsis thaliana genome contains 11 genes encoding for histone H2B (HTBs), 13 for H2A (HTAs), 15 for H3 (HTRs), and 8 genes encoding for histone H4 (HFOs). The finding that histone variants may be expressed in specific tissues and/or during specific developmental stages, often displaying specific nuclear localization and involvement in specific nuclear processes suggests that histone variants have evolved to carry out specific functions in regulating chromatin structure and function and might be important for better understanding of growth and development and particularly the response to stress. In this review, we will elaborate on a group of core histone proteins in Arabidopsis, namely histone H2B, summarize existing data, and illuminate the potential function of H2B variants in regulating chromatin structure and function in Arabidopsis thaliana.

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GDF11 Rejuvenates Cerebrovascular Structure and Function in an Animal Model of Alzheimer’s Disease

Journal of Alzheimer s Disease ◽

10.3233/jad-170474 ◽

2018 ◽

Vol 62 (2) ◽

pp. 807-819 ◽

Cited By ~ 13

Author(s):

Wei Zhang ◽

Yi Guo ◽

Bo Li ◽

Qi Zhang ◽

Jian-hui Liu ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Animal Model ◽

Structure And Function ◽

Model Of Alzheimer’S Disease ◽

And Function

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Foliar colleters in Macrocarpaea obtusifolia (Gentianaceae): anatomy, ontogeny, and secretion

Botany ◽

10.1139/cjb-2013-0203 ◽

2014 ◽

Vol 92 (1) ◽

pp. 59-67 ◽

Cited By ~ 12

Author(s):

Valdnéa Casagrande Dalvi ◽

Lucas Siqueira Cardinelli ◽

Renata Maria Strozi Alves Meira ◽

Aristéa Alves Azevedo

Keyword(s):

Chemical Nature ◽

Developmental Stages ◽

Structure And Function ◽

Histochemical Analysis ◽

Secretory Structures ◽

Standard Type ◽

Vegetative Organs ◽

New Information ◽

And Function ◽

First Time

Colleters are secretory structures located in reproductive and (or) vegetative organs of many eudicots. In Gentianaceae Juss., the presence of foliar colleters has been neglected, and anatomical and histochemical studies are scarce. The objectives of this study were to investigate the anatomy, ontogeny, and chemical nature of the secretion found in Macrocarpaea obtusifolia (Griseb.) Gilg colleters to establish a relationship between their structure and function and check whether these structures are similar to those described for other genera of the Gentianaceae and other families of the Gentianales. Samples of leaves at different developmental stages were collected and processed for anatomical and histochemical analysis using light microscopy and scanning electron microscopy. Colleters in M. obtusifolia have a protodermal origin, are of standard type, and are not vascularized. Young colleters are translucent and produce an abundant amount of sticky secretion. Later, they turn yellowish with a blackened region at the apex of the head, and the secretion, composed of polysaccharides and proteins, becomes less abundant and brownish. During senescence, the process begins with complete degradation and cell collapse of the secretory portion. The colleters of the standard type in M. obtusifolia have been observed for the first time in the Gentianaceae and represent additional evidence that reinforces how common this type of colleter is in the Gentianales. Such results provide new information on the anatomy, ontogeny, histochemistry, and colleter types of Gentianaceae.

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Centromere identity and function put to use: construction and transfer of mammalian artificial chromosomes to animal models

Essays in Biochemistry ◽

10.1042/ebc20190071 ◽

2020 ◽

Vol 64 (2) ◽

pp. 185-192

Author(s):

Ye Yang ◽

Michael A. Lampson ◽

Ben E. Black

Keyword(s):

Gene Expression ◽

Cell Culture ◽

Animal Model ◽

Synthetic Biology ◽

Animal Models ◽

Model Systems ◽

Expression Vectors ◽

Artificial Chromosomes ◽

Conventional Expression ◽

And Function

Abstract Mammalian artificial chromosomes (MACs) are widely used as gene expression vectors and have various advantages over conventional expression vectors. We review and discuss breakthroughs in MAC construction, initiation of functional centromeres allowing their faithful inheritance, and transfer from cell culture to animal model systems. These advances have contributed to advancements in synthetic biology, biomedical research, and applications in industry and in the clinic.

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Calycinal trichomes in Ipomoea cairica (Convolvulaceae): ontogenesis, structure and functional aspects

Australian Journal of Botany ◽

10.1071/bt10194 ◽

2011 ◽

Vol 59 (1) ◽

pp. 91 ◽

Cited By ~ 22

Author(s):

Elder Antônio Sousa Paiva ◽

Luiza Coutinho Martins

Keyword(s):

Electron Microscopy ◽

Developmental Stages ◽

Glandular Trichomes ◽

Structure And Function ◽

Short Stalk ◽

Transmission Electron ◽

Functional Aspects ◽

Acidic Polysaccharides ◽

Low Humidity ◽

And Function

The presence of calycinal trichomes in Ipomoea has been neglected, which renders the interpretation of their functions difficult. The present work aims to characterise the structure, as well as the composition of the secretion of calycinal trichomes in Ipomoea cairica, in order to establish a relationship between their structure and function. Samples of floral buds at different developmental stages and sepals from fruits were collected and fixed for study under light as well as under scanning and transmission electron microscopy. The calyx of I. cairica is persistent and presents glandular trichomes which produce acidic polysaccharides. The trichomes are peltate and consist of a short stalk and a pluricellular secretory portion. The cells from the secretory portion contain a dense and organelle-rich cytoplasm. The fresh secretion is hyaline and fluid, but solidifies when exposed to low humidity, taking on a crystalline and fragile aspect, and they return to a gel state when in the presence of water. The calycinal trichomes in I. cairica show great structural and ultrastructural similarities to colleters and can be considered functionally analogous. The secretion, which is highly hygroscopic, spreads along the surface of the corolla and of the fruit, apparently protecting these structures against desiccation.

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A Systematic Review of the Influence of Continuous Positive Airway Pressure on Fetal and Newborn Animal Models: Suggestions to Improve Neonatal Respiratory Care

Neonatology ◽

10.1159/000511086 ◽

2020 ◽

Vol 118 (1) ◽

pp. 5-14

Author(s):

Andre George Gie ◽

Talia Rose Hubble ◽

Yannick Regin ◽

Thomas Salaets ◽

Monica Zamora ◽

...

Keyword(s):

Systematic Review ◽

Continuous Positive Airway Pressure ◽

Animal Models ◽

Airway Pressure ◽

Positive Airway Pressure ◽

Structure And Function ◽

Newborn Animal ◽

Lung Structure ◽

Surfactant Administration ◽

And Function

Introduction: Prematurely born infants regularly develop respiratory distress syndrome and require assisted ventilation. Ventilation may injure the premature lung and increase the risk of bronchopulmonary dysplasia. Continuous positive airway pressure (CPAP), a form of noninvasive ventilation, is commonly used in modern neonatology. Limited clinical data are available on the acute and long-term effect of neonatal exposure to CPAP on the lung. Given the restricted clinical data, newborn animal models have been used to study the influence of CPAP on lung structure and function. The findings of animal studies can guide neonatal care and improve the use of CPAP. Methods: A systematic review of electronic databases (Medline, Embase, and Cinahl) was performed using the medical subject heading terms, “CPAP” or “continuous positive airway pressure” and “animals” and “newborn.” Abstracts were screened for inclusion using predetermined eligibility criteria. Results: In total, 235 abstracts were identified and screened for inclusion. Of these, 21 papers were included. Large (N = 18) and small (N = 3) animal models investigated the effects of CPAP. Pulmonary outcomes included gas exchange, lung structure and function, surfactant metabolism, lung inflammation and injury, and the effect of intrapulmonary therapy. Compared to mechanical ventilation, CPAP improves lung function, evokes less lung injury, and does not disrupt alveolar development. Surfactant administration combined with CPAP further improves respiratory outcomes. Of concern are findings that CPAP may increase airway reactivity. Discussion/Conclusion: CPAP offers numerous advantages over mechanical ventilation for the immature lung. The combination of CPAP and exogenous surfactant administration offers further pulmonary benefit.

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