Reproductive physiology of the female cat

Ovarian cyclicity induces considerable changes in morphology, physiology and function of the reproductive organs in animals. This thesis aimed to study reproductive physiology of the female domestic cat, focusing on the cervix, uterus and uterine tube during different stages of the oestrous cycle, after mating and under pathological conditions. Transcervical catheterisation was performed using a specially designed catheter. Patency of the cervix and uterine motility were studied with the aids of fluoroscopy and scintigraphy by depositing contrast fluids and radiopharmaceutical medium in the cranial vagina. The relationship between cervical patency and oestrous behaviour, cornification of the vaginal cells and serum concentrations of oestradiol-17β were evaluated. Hysterography, a positive contrast study, was performed to illustrate the uterine appearance during the oestrous cycle in relation to histological characteristics of the endometrium. Immunohistochemistry using proliferating nuclear antigen (PCNA) was introduced to identify mitotic activity of the endometrial cells. Patency of the cervix to spermatozoa as well as sperm distribution after natural mating was evaluated by flushing the vagina, the uterus and the uterine tube. For the study of sperm distribution in the female reproductive tract, two methods, flushing and tissue sectioning were evaluated and compared. Using a specially designed catheter it was possible to catheterise the cervix during interoestrus, oestrus, metoestrus and postpartum and to introduce contrast fluids into the uterus to study uterine appearance using hysterography also when the cervix was closed. The period when the cervix was patent was found to vary among individuals: the cervix was open either only during late-oestrus; during midoestrus and late-oestrus; or throughout the entire behavioural oestrus. Patency of the cervix was found to usually coincide with the maximum degree of vaginal cornification and thus, presumably is regulated at least in part by the serum concentration of oestradiol-17β. Hysterograms revealed differences in uterine luminal shape that corresponded to the histological characteristics of the endometrium in cats at various stages of the oestrous cycle, cats given medroxyprogesterone acetate (MPA) and cats with uterine pathology. Straight- and wavy-shaped uterine lumens were characteristic of the uterine horns in the inactive and follicular stages of the oestrous cycle, respectively. Coil-shaped uterine lumen appeared to be a progestagenic effect seen in the luteal, the MPA-treated and the pathological groups. A coiled uterine cavity was suggestive of endometrial hyperplasia, whereas irregular filling defects were indicative of generalised cystic changes in the endometrium. The expression of PCNA in luminal and glandular epithelial cells was observed although the mitotic activity was not related to neither stages of oestrous cycle nor uterine pathological conditions. The results from the sperm distribution study demonstrated that the cervix and the uterotubal junction (UTJ) were sperm barriers in the cat. The endometrial crypts and the UTJ functioned as sperm reservoirs before ovulation, whereas the isthmus was a sperm reservoir around the time of ovulation. The observations determined the dynamics of the cervix, the uterus and the uterine tube in the cat in relation to ovarian activity. This thesis is the first to provide nomenclatures for describing uterine appearance in hysterograms according to the shape of the uterine horns, luminal cavity and the characteristics of the intraluminal lining, to demonstrate the PCNA expression as well as to determine the distribution of spermatozoa in the female reproductive tract of the cat after natural mating

Multi-sensor rainfall data assimilation using ensemble approaches

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2006.Includes bibliographical references (p. 195-203).Rainfall is a major process transferring water mass and energy from the atmosphere to the surface. Rainfall data is needed over large scales for improved understanding of the Earth climate system. Although there are many instruments for measuring rainfall, none of them can provide continuous global coverage at fine spatial and temporal resolutions. This thesis proposes an efficient methodology for obtaining a probabilistic characterization of rainfall over an extended time period and spatial domain. The characterization takes the form of an ensemble of rainfall replicates, each conditioned on multiple measurement sources. The conditional replicates are obtained from ensemble data assimilation algorithms (Kalman filters and smoothers) based on a recursive cluster rainfall model. Satellite measurements of cloud-top temperatures are used to identify areas where rainfall can possibly occur. A variational field alignment algorithm is used to estimate rainfall advective velocity field from successive cloud-top temperature images. A stable pseudo-inverse improves the stability of the algorithms when the ensemble size is small. The ensemble data assimilation is implemented over the United States Great Plains during the summer of 2004.(cont.) It combines surface rain-gauge data with three satellite-based instruments. The ensemble output is then validated with ground-based radar precipitation product. The recursive rainfall model is simple, fast and reliable. In addition, the ensemble Kalman filter and smoother are practical for a very large-scale data assimilation problem with a limited ensemble size. Finally, this thesis describes a multi-scale recursive algorithm for estimating scaling parameters for popular multiplicative cascade rainfall models. In addition, this algorithm can be used to merge static rainfall data from multiple sources.by Virat Chatdarong.Ph.D

Artificial recharge for conjunctive use in irrigation : the San Joaquin Valley, California

Thesis (M.Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2001.Includes bibliographical references (leaf 60).One classical solution for dealing with surface water fluctuation is to construct a surface reservoir. However, because a surface reservoir requires too much land and has high negative impact on the environment, the use of a natural aquifer as a subsurface reservoir is proposed. In this solution, restoration of water to an aquifer requires an artificial recharge method. It is deduced that for irrigation purposes, a direct surface recharge is the most appropriate method to use because of its low cost of construction, operation and maintenance. To store water for agriculture, the capacity to recharge water within a limited time is the most important characteristic determining the feasibility of artificial recharge. Regarding a direct surface method, this capability is mainly governed by soil properties, depth to groundwater table, and spacing between two adjacent recharge areas. Under proper conditions, sufficient amounts of recharge water can store for agricultural purposes within a region. This study shows that total costs to construct, operate and maintain artificial recharge facilities are relatively low compared to the benefits that are expected from the recharge project. This implies th, - an artificial recharge scheme is a practical way to restore water to an aquifer, and use it in conjunction with surface water for irrigation.by Virat Chatdarong.M.Eng

Cell cycle analysis and interspecies nuclear transfer of cat cells treated with chemical inhibitors

This study investigated the effect of chemical inhibitors on the cell-cycle synchronisation in cat fibroblast cells and evaluated the development of interspecies embryos reconstructed from cat donor cells and enucleated bovine oocytes. Cat fibroblast cells were treated with 15 μg/mL roscovitine or 0.05 μg/mL deme-colcine prior to cell cycle analysis and nuclear transfer. The percentage of cat fibroblast cells arrested at the G0/G1 phase in the roscovitine group was similar to that in the control group without any treatment. The percentage of cells arrested at the G2/M phase was significantly higher in the demecolcine group than in the control group. The fusion rate of interspecies couplets was significantly greater in the roscovitine group than in the control group. Most embryos stopped the development at the 2- or 4-cell stage, and none developed into blastocysts. Chemical inhibitor-induced donor cell cycle synchronisation did not overcome developmental arrest in interspecies cloned embryos

HISTONE H3 MODIFICATION OF ISCNT EMBRYOS

This study aimed to determine the acetylation patterns on histone H3K9/18/23 and the dimethylation pattern on histone H3K9 during early embryogenesis among 50 nM Trichostatin A (TSA)-treated iSCNT cat-cow embryos, untreated iSCNT cat-cow embryos (control) and bovine in vitro fertilisation (IVF) embryos, because TSA-treated iSCNT embryos are able to develop into blastocysts. The results show that the acetylation levels of H3K9/18/23 in the TSA-treated iSCNT and bovine IVF embryos were higher than those in the control embryos at almost all of the examined stages (2 h post-fusion / post-insemination (PF/PI), pronuclear (PN), two-cell, four-cell and eight-cell stages). At 6 h PF/PI the acetylation levels on H3K9/23 in the TSA-treated iSCNT and bovine IVF embryos were lower than those in the control, and there was no difference in the acetylation levels of H3K18 among the three groups. The acetylation levels of H3K9/23 increased either in the TSA-treated iSCNT or and bovine IVF embryos increased when those embryos developed to the PN and two-cell stages. The dimethylation level of H3K9 in the TSA-treated iSCNT embryos resembled that of the bovine IVF embryos at all examined stages (2h PF/PI, 6 h PF/PI and PN stages), and these levels were greater than those of the control. This result suggests that treatment of iSCNT embryos with TSA modifies the patterns of histone acetylation and dimethylation at certain lysine residues in a manner that is comparable with that seen in IVF embryos during early embryogenesis

Seasonality in oestrus and litter size in an assistance dog breeding colony in the United Kingdom.

Evidence of seasonality in oestrus in bitches within specialist breeding programmes, such as those for assistance dogs, may support colony management through tailoring the distribution of resources required for breeding throughout the year. However, at present there are conflicting data regarding seasonality in oestrus (and litter size) in domestic dogs. The primary objective of this study was to investigate seasonal variations in oestrus and litter size in a large assistance dog breeding colony in the UK in order to optimise colony management. The authors analysed the annual distribution of 3624 observations of oestrus collected from 568 brood bitches from January 2005 to June 2014. The authors also evaluated the relationship between month and litter size for 1609 litters observed during the same period. There was no evidence of regular seasonal variations in oestrus or litter size by meteorological season or month. The lack of seasonality in oestrus may be a function of dogs in the UK, particularly valuable breeding bitches, being exposed to fairly constant environmental conditions throughout the year as a consequence of artificial light and heating during the winter months. The authors' findings suggest that special consideration of the annual distribution of oestrus and litter size is unnecessary for the management of assistance dog breeding colonies similar to those in the UK