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Author: Sardul S. Guraya Publisher: Springer Science & Business Media ISBN: 3642836283 Category : Science Languages : en Pages : 296
Book Description
In 1954, when I obtained my B. Sc. (Honours School) degree in Zoology, I was asked by my advisor, the late Professor Vishwa Nath, to make comparative cytological studies of oogenesis in birds for my M. Sc. (Honours School) thesis submitted to the Panjab University in 1956. Using the classical techniques of cytology, I studied the various aspects of follicle growth and atresia in five species of birds. Professor Vishwa Nath, who himself devoted most of his life to the study of the comparative cytology of gametogenesis in animals, was so much impressed by my findings on avian oogenesis that he asked me to continue my research work for the Ph. D. degree under his supervision. During my research work on avian oogenesis, I became very much interested in further comparative study of ovarian follicles in vertebrates and thus decided to make comparative, morphological and histochemical studies of ovarian follicles in reptiles, birds and mammals. Actually, very little information was available in this regard in 1957 when I started working for the Ph. D. degree. In subsequent years, I and my numerous dedicated and highly motivated M. Sc. and Ph. D. students con tinued to make comparative, morphological, histochemical, biochemical and physiological studies of ovarian follicles in all groups of vertebrates. In connection with the subject of this book, I would like to make special mention of my two brilliant students, namely Dr. S. K. Varma and Dr. R. K.
Author: Sardul S. Guraya Publisher: Springer Science & Business Media ISBN: 3642836283 Category : Science Languages : en Pages : 296
Book Description
In 1954, when I obtained my B. Sc. (Honours School) degree in Zoology, I was asked by my advisor, the late Professor Vishwa Nath, to make comparative cytological studies of oogenesis in birds for my M. Sc. (Honours School) thesis submitted to the Panjab University in 1956. Using the classical techniques of cytology, I studied the various aspects of follicle growth and atresia in five species of birds. Professor Vishwa Nath, who himself devoted most of his life to the study of the comparative cytology of gametogenesis in animals, was so much impressed by my findings on avian oogenesis that he asked me to continue my research work for the Ph. D. degree under his supervision. During my research work on avian oogenesis, I became very much interested in further comparative study of ovarian follicles in vertebrates and thus decided to make comparative, morphological and histochemical studies of ovarian follicles in reptiles, birds and mammals. Actually, very little information was available in this regard in 1957 when I started working for the Ph. D. degree. In subsequent years, I and my numerous dedicated and highly motivated M. Sc. and Ph. D. students con tinued to make comparative, morphological, histochemical, biochemical and physiological studies of ovarian follicles in all groups of vertebrates. In connection with the subject of this book, I would like to make special mention of my two brilliant students, namely Dr. S. K. Varma and Dr. R. K.
Author: S.S. Guraya Publisher: Springer Science & Business Media ISBN: 364270154X Category : Medical Languages : en Pages : 542
Book Description
Both functions of the mammalian ovary, the endocrine and (synthesis and secretion of steroid hormones) and exocrine (production of ova), depend upon the presence and cyclic growth of follicles, as the depletion of primordial follicles from the ovary leads to cessation of these f-unctions or female reproduction in mammals, or to postmenopausal period in humans. Actually, various fertility and sterility problems at the ovarian level are related to follicles. Therefore, a thorough understanding of the biology of ovarian follicles in mammals is of fundamental interest to a wide variety of academic and scientific disciplines. Study of their structure, function, and control involves mor phology, including ultrastructure, cell biology, physiology, endocrinology, biochemis try, immunology, neurobiology and pharmacology. Zoologists take interest in comparative and evolutionary aspects of biology of ovarian follicles in many different groups of mammals. Agricultural scientists and wildlife biologists need a thorough knowledge of the biology of follicles to control more effectively fecundity in domestic animals and endangered species of mammals. Finally, clinical scientists, toxicologists and physicians want to know the normal and pathological features of ovarian follicles in women, especially in relation to health and the regulation of fertility. Having in view the great importance of studying various aspects of biology of ovarian follicles, numerous papers and reviews on several aspects of ovarian follicles are published annually in a wide variety of scientific journals.
Author: David O. Norris Publisher: Springer Science & Business Media ISBN: 1461318696 Category : Science Languages : en Pages : 627
Book Description
Comparative endocrinology is one of the most rapidly developing subdis ciplines within the field of endocrinology, and it is having a significant impact on research at the molecular, cellular, organisma1 and environmental levels. Much of the current ferment in endocrinology is in reproductive endocrinology. The purpose of this volume on hormones and reproduction in fishes, amphibians and reptiles is to summarize our present understandings and to identify important research problems to be addressed in the area of comparative reproductive endocrinology. It was inspired by the gathering at Copper Mountain, Colorado, of eminent endocrine scientists from around the world on the occasion of the Tenth International Symposium on Comparative Endocrinology in July, 1985. While preparing for that meeting, we decided that a special volume on reproductive endocrinology was needed to summarize what is known and to stimulate research in particular directions. Why do we emphasize fishes, amphibians and reptiles? First, knowledge about the reproductive endocrinology of these ectothermic vertebrates can provide a clearer picture of the evolution of reproductive hormones and their effects on target organs. This comparative approach can lead to new theories about the evolution of reproductive control mechanisms. Second, studies concerning the reproductive endocrinology of "lower" vertebrates can result in development of "model systems" for application to studies of birds and mammals. Indeed, information about the patterns of reproductive control in ectothermic vertebrates can tell us which are evolutionarily stable and which are labile.
Author: Kahina Ghanem Publisher: ISBN: Category : Languages : en Pages :
Book Description
The commercial laying hen constitutes an excellent model organism to study ovarian follicle development in Galliformes and to use as a comparative model organism to other birds, reptiles and mammals. Because eggs are laid in sequences (clutches), whereby one egg is laid per day, the chicken left, and only functional ovary contains follicles at virtually all stages of development. To enable daily egg laying, the ovary contains a hierarchy of rapidly growing preovulatory follicles which are arranged by size and maturity. After almost each oviposition, the largest follicle of the preovulatory hierarchy is ovulated. The number of preovulatory follicles is, in turn, replenished by a process referred to as cyclic recruitment. During cyclic recruitment a single follicle is recruited from a pool of pre-recruitment follicles that are also arranged into a size hierarchy, to transition to the rapid growth phase and to assume the position of the smallest follicle of the preovulatory hierarchy. Recruitment of a single follicle at the appropriate time interval ensures the maintenance of the follicle hierarchy and the timely maturation of preovulatory follicles for ovulation. The process of cyclic recruitment is known to be at least partially driven by the sensitization of the granulosa cell (GC) layer from the largest the pre-recruitment follicle to pituitary-derived follicle stimulating hormone (FSH) and the initiation of receptor-mediated cyclic adenosine monophosphate production. However, the exact mechanism that initiates this sensitization is still unknown. The first objective of the present work was to determine if pre-recruitment follicles are differentially responsive to FSH according to size, in vivo. Results indicated that in vivo injection of exogenous FSH induced recruitment of multiple pre-recruitment follicles within the duration of an ovulatory cycle, in a dose-dependent manner. These results indicate that pre-recruitment follicles are differentially responsive to FSH, in vivo, and the GC layer can respond to FSH to initiate differentiation when adequately stimulated. Moreover, under normal circumstances there is an inhibitory mechanism that prevents follicles from responding to normal circulating concentrations of FSH, but that there is an FSH concentration threshold above which pre-recruitment follicles respond and the threshold increases as the follicle size decreases. To determine potential markers in pre-recruitment follicles that confer an increased ability to respond to FSH as they increase in size, the second objective of the present work was to characterize changes in protein expression in the four largest pre-recruitment and the most recently recruited follicles. Results from a shotgun proteomics study indicated that there were no significant changes detected within the theca from the largest pre-recruitment follicle compared to the most recently recruited follicle. Within GC layers, a comparison between the most recently recruited follicle and the 4 largest pre-recruitment follicles determined that very few proteins ( 6) were differentially expressed, all of which were involved in cholesterol or yolk transport. These proteins are synthesized in the liver and are then transported in the plasma to the ovary. The protein profile of the largest pre-recruitment follicle was more similar to that of the most recently recruited follicle than those from the 2nd, 3rd and 4th largest pre-recruitment follicles. Pathway analysis indicated that, in GC from the most recently recruited follicle, transforming growth factor beta 1 and microRNA-21 pathways were predicted to be activated, whereas the pro-apoptotic cytokine oncostatin M pathway was predicted to be inhibited. We also report for the first time, expression of G-protein coupled receptor ligand RELAXIN-3 protein and mRNA in GC but not theca from pre-recruitment follicles, with highest expression detected in the most recently recruited follicle. The results suggest that the few changes in protein expression detected in pre-recruitment follicles are in GC and not TH. Accordingly, it is proposed that cyclic recruitment is primarily driven by rapid changes in signal transduction, and RELAXIN-3 signaling may play an important role in mediating these changes.Determining if cyclic recruitment and ovulation are functionally linked would greatly facilitate determining the exact time of cyclic recruitment and inform investigations on the most proximal event that leads to cyclic recruitment. Accordingly, the third objective of the present work was to determine if failure of ovulation leads to failure of cyclic recruitment. Results determined that cyclic recruitment can occur even when ovulation fails to occur. In addition, cyclic recruitment and ovulation did not appear to occur at the same time of the day. These results indicate that the mechanisms regulating time of cyclic recruitment are independent of the ovulatory cycle. We conclude that cyclic recruitment is a continuous process whereby a pre-recruitment follicle gains responsiveness to FSH as it increases in size. Although cyclic recruitment is mediated at least in part by changes in protein expression in GC, it is most likely driven by rapid changes in cell signaling due to sensitization of G-protein coupled receptors that stimulate cAMP production. Finally, time and occurrence of cyclic recruitment are not linked to time and occurrence of ovulation. We propose instead that time of cyclic recruitment is pre-determined by the position the follicle will assume in the ovulatory sequence which, in turn is most likely determined during early stages of pre-recruitment follicle development.
Author: Stephen J. Divers Publisher: Elsevier Health Sciences ISBN: 0323482481 Category : Medical Languages : en Pages : 1793
Book Description
**Selected for Doody’s Core Titles® 2024 in Veterinary Medicine** Known as "the bible" of herpetological medicine and surgery, Mader’s Reptile and Amphibian Medicine and Surgery, 3rd Edition edited by Stephen Divers and Scott Stahl provides a complete veterinary reference for reptiles and amphibians, including specific sections on practice management and development; taxonomy, anatomy, physiology, behavior, stress and welfare; captive husbandry and management including nutrition, heating and lighting; infectious diseases and laboratory sciences; clinical techniques and procedures; sedation, anesthesia and analgesia; diagnostic imaging; endoscopy; medicine; surgery; therapy; differential diagnoses by clinical signs; specific disease/condition summaries; population health and public health; and legal topics. Well-organized and concise, this new edition covers just about everything related to reptiles and amphibians by utilizing an international array of contributing authors that were selected based on their recognized specialization and expertise, bringing a truly global perspective to this essential text!
Author: Jennifer E. Graham Publisher: John Wiley & Sons ISBN: 1119149231 Category : Medical Languages : en Pages : 996
Book Description
Exotic Animal Emergency and Critical Care Medicine delivers the most relevant and current information required by general veterinary practitioners and veterinary specialists in treating emergent and critical exotic patients. Covering the management of common emergency presentations in exotic companion mammals, birds, reptiles, and amphibians, each section discusses triage and stabilization, diagnostics, nutrition and fluid therapy, analgesia, anesthesia, monitoring, CPR, and euthanasia. The book includes quick reference tables, species-specific drug formularies, and illustrations of exotic animal emergency procedures and techniques. The information contained within is based on an extensive review of the most current literature and the combined knowledge and expertise of international leaders in the field of exotic animal medicine and surgery. A one-stop resource like no other, Exotic Animal Emergency and Critical Care Medicine makes it easy to find the information needed to effectively treat urgent and life-threatening conditions in pet exotic animals. The book covers a wide range of species, encompassing: Exotic companion mammals, including ferrets, rabbits, guinea pigs, chinchillas, rats, mice, hamsters, gerbils, hedgehogs, and sugar gliders Birds, including psittacines, passerines, doves and pigeons, as well as backyard poultry and waterfowl Reptiles, including turtles and tortoises, snakes and lizards Amphibians Equally useful for general practitioners, specialists in emergency and critical care and exotic animal medicine, veterinary students, and trainees, Exotic Animal Emergency and Critical Care Medicine is an essential resource for the emergent and critical care of exotic animals.
Author: Publisher: Academic Press ISBN: 012816834X Category : Science Languages : en Pages : 362
Book Description
Amphibian Models of Development and Disease, Volume 145 in the Current Topics in Developmental Biology series, highlights new advances in the field written by an international board of experts. New chapters in this release include Building a ciliated epithelium: Transcriptional regulation and radial intercalation of multiciliated cells, Biomechanics of Amphibian Morphogenesis, Planar cell polarity during neural tube closure, Xenopus neural crest and its relevance to human disease, Endoderm organogenesis, From egg to embryo in marsupial frogs, Evo-devo lessons from the analysis of Xenopus genomes, Transcriptional regulation during zygotic genome activation, Proteomics and metabolomics for cell lineage analysis in frog embryos, and more. Provides the authority and expertise of leading contributors from an international board of authors Presents the latest release in the Current Topics in Developmental Biology series Includes the latest information on Amphibian Models of Development and Disease
Author: Justin L. Rheubert Publisher: CRC Press ISBN: 1466579870 Category : Nature Languages : en Pages : 742
Book Description
Reproductive Biology and Phylogeny of Lizards and Tuatara is a remarkable compendium of chapters written by the world's leading experts from over four continents. The book begins with a chapter recounting historical discoveries in reproductive biology and a review of phylogenetics and up-to-date hypotheses concerning evolutionary relationships amon
Author: Sardul S. Guraya
Author: Sardul S. Guraya
Author: Sardul S. Guraya
Author: S.S. Guraya
Author: David O. Norris
Author: Henry Sheldon Fitch
Author: Kahina Ghanem
Author: Stephen J. Divers
Author: Jennifer E. Graham
Author: 
Author: Justin L. Rheubert