Innervation of internal female genital organs in the pig during prenatal development.

This study investigated the innervation of internal genital organs in 5-, 7- and 10-week-old female pig foetuses using single and double-labelling immunofluorescence methods. The structure and topography of the organs was examined using a scanning electron microscope (SEM). The investigations revealed differences in the innervation between the three developmental periods. Immunostaining for protein gene product 9.5 (PGP; general neural marker) disclosed solitary nerve fibres in the external part of the gonadal ridge and just outside of the mesenchyme surrounding mesonephric ducts in 5-week-old foetuses. Double-labelling immunohistochemistry revealed that nerve fibres associated with the ridge expressed dopamine ß-hydroxylase (DßH; adrenergic marker) or vesicular acetylcholine transporter (VAChT; cholinergic marker). In 7-week-old foetuses, the PGP-positive nerve terminals were absent from the gonad but some of them ran outside and along, and sometimes penetrated into the mesenchyme surrounding the tubal and uterine segments of the paramesonephric ducts and uterovaginal canal. Few axons penetrated into the mesenchyme. DßH-positive fibres were found in single nerve strands or bundles distributed at the edge of the mesenchyme. VAChT-positive nerve terminals formed delicate bundles located at the edge of the mesenchyme, and the single nerves penetrated into the mesenchyme. DßH was also expressed by neurons which formed cell clusters comprising also DßH- or VAChT-positive nerve fibres. In 10-week-old foetuses, PGP-positive nerve fibres were still absent from the ovary but some were distributed in the mesenchyme associated with the uterovaginal canal and uterine and a tubal segment of the paramesonephric ducts, respectively. DßH- or VAChT-positive nerve fibres were distributed at the periphery of the mesenchyme associated with the uterovaginal canal. Some DßH- and many VAChT-positive nerve fibres were evenly distributed throughout the mesenchyme. The clusters of nerve cells comprised DßH-positive perikarya and DßH- or VAChT-positive nerve fibres. The investigations revealed no DßH/VAChT-positive nerve fibres or neurons as well as no nerve structures stained for calcitonin gene-related peptide and/or substance P (sensory markers) associated with the genital organs in the studied prenatal periods.

Morphogenesis of the uterine tube in the European shorthair cat in the prenatal and postnatal period: Light microscopy and three-dimensional reconstruction study.

The study aimed to describe the morphogenesis of the domestic cat uterine tube, from the primordial tubal segment of the paramesonephric duct (TsPD) to the mature organ. The specific aims included identifying differences in the rate and way of development of the layers in the wall of the infundibulum, the ampulla, and the isthmus. In the study we conducted light microscopic (LM) observations of the uterine tube wall, and analysis of 3D models, which were used for the first time to visualize the arrangement of the paramesonephric duct and highlight the pattern of the developing mucosal folds. The results revealed the two stages in the prenatal development of the domestic cat uterine tube. The first stage lasts from day 26-44 p.c. (post-conception) and includes the growth of the TsPD. It starts with formation of the TsPD's epithelial tubule in the mesenchyme of the anterior part of the mesonephros. The tubule, surrounded by mesenchyme, elongates posteriorly, and the TsPD can be divided into three sections according to their location and diameter, i.e., anterior, middle, and posterior. The first stage ends with the histodifferentiation of the mesenchyme into loose connective tissue and mucosa formation. The second stage lasts from approximately day 45-63 p.c. and comprises the formation of the proper layers in the uterine tube wall. The pace and pattern of layers' development are specific to each section of the uterine tube, as tissues first differentiate in its anterior part and then continue posteriorly. The mucosal folds appear after day 44 p.c. in the infundibulum, and they become long and branched by the end of the prenatal period. Then, approximately day 48 p.c., the single mucosal folds appear in the ampulla, and at the end, i.e., about day 63 p.c., they become visible in the isthmus. The 3D models revealed the unique spiral-shaped arrangement of the mucosal folds in the ampulla. The tunica muscularis starts to develop ca day 48-51 p.c. in the anterior part of the uterine tube. On approximately day 55 p.c., the circular muscle layer can be distinguished in the ampulla, while in the isthmus, it develops just before birth. The postnatal development of the infundibulum includes the formation of the labyrinth-like system of mucosal folds, whereas in the ampulla and isthmus, branched mucosal folds and the second longitudinal muscle layer develop postnatally. At the end of the prenatal period, the differences in the wall thickness between the individual segments of the uterine tube reflect the proper proportions of the uterine tube wall in the mature female.

Microstructural changes of the wall of uterine horn in the domestic cat (Felis silvestris catus) during postnatal development.

The study describes the details of histological changes occurring during the postnatal development of the wall of the uterine horn in the European shorthair domestic cat. Light microscope observations and morphometric analysis were carried out to investigate the rate of development of the wall of the uterine horns in order to estimate the maturing time. Uterine horns of newborn and 1week-old cats are fetal-like and showing smooth, nonfolded endometrium lined with pseudostratified epithelium, deprived of uterine glands, and poorly developed two-layered myometrium. The lamina propria of the mucosa becomes folded in the first month of postnatal life. At the same time, the primordia of the uterine glands appear, elongating, doubling in number and reaching the basal layer by sixth month of age. In six-month-old cats, the lamina propria of the mucosa is formed into the functional and basal layer and its thickness increases rapidly. Until the sixth month of age, the inner circular muscle layer is the widest part of the myometrium, the outer longitudinal layer is the thinnest, while the width of the vascular layer is an intermediate value between the width of the inner and outer layer. From the seventh month of age, the proportion of the thickness of the inner and outer layer is reversed and the vascular layer becomes the thinnest part of the myometrium. Between seventh and twelfth month of age, the structure of the wall of the uterine horn does not change significantly, as the longitudinal mucosal folds limiting the narrow lumen of the uterine horns, and the arrangement of the layers in the wall is assigned to a pattern according to which the endometrium represents about 40% of the total width of the wall, while the myometrium is about 60%. In the studied time span of postnatal life, the average thickness of the wall of the uterine horn increases 9.4 -fold, the thickness of the lamina propria and mucosal folds increases 6.9-fold and 3.8-fold, respectively, while the thickness of the myometrium increases 17.3-fold. Summing up, the process of maturation of the wall of the uterine horns in the domestic cat lasts up to sixth month of postnatal life and includes the formation of the endometrial longitudinal folds, appearance and development of the uterine glands, division of the lamina propria of the mucosa into the functional and basal layers, and continued development of the circular, vascular and longitudinal muscle layers.

Ultrastructural study of uterine epithelium in the domestic cat during prenatal development.

The study describes the sequence of ultrastructural changes of the endometrial lining epithelium, first in the primordial paramesonephric ducts, then in the differentiating uterine horns, and finally in the mature uterus. The research material comprised female fetuses of the domestic cat, aged 33-63 days post conceptionem (p.c.), and mature females. The ultrastructural observations of the developing epithelium were conducted using transmission electron microscopy (TEM) and light microscopy (LM). The results revealed two basic stages in the development of the uterine mucosal epithelium in the domestic cat: the development of the epithelium of the uterine segment of the paramesonephric ducts, lasting from day 33 to day 42 p.c., and the differentiation of this epithelium into the mucosal epithelium of the uterus, starting after day 42 p.c. and lasting until the end of the prenatal period. The epithelium of the uterine segments of the paramesonephric ducts is pseudostratified with a flat surface, all cells being characterized by the same distribution of desmosomes, ribosomes, rough endoplasmic reticulum (rER) cisternae, and mitochondria in the cytoplasm. The differentiating epithelium of the uterus after day 51 p.c. is pseudostratified with a varied height. In the epithelial cells there are increases of (i) the number and complexity of the junctional complexes, (ii) the number of invaginations of the lateral cell membranes, and (iii) the number of elongated mitochondria, and also there appear distended cisternae of the rER, lipid droplets and clusters of glycogen, which suggest increasing metabolism and secretory activity of the cells during the transformation of the epithelium.

Morphology and topography of internal reproductive organs in the female cat during prenatal and postnatal development: Scanning electron microscope and three-dimensional reconstruction study.

The study describes the morphology and topography of internal reproductive organs in the domestic cat from the early prenatal period to maturity, using macroscopic and scanning electron microscope (SEM) observations with three-dimensional (3D) reconstructions. Fifty-seven female cat fetuses aged between the 27th and 63rd day postconception (p.c.), two newborn cats, three juveniles (3-month-old) cats, and three mature (12-month-old) cats were used in the study. The age of fetuses was determined on the basis of the growth curve for the domestic cat. The rudiments of cat ovaries develop on the ventral surface of the mesonephroi and within 30 days p.c. move to the sides of the abdominal cavity, which is similar to the position of the ovaries in the adult cat. The mesonephroi regress at about the 50th day p.c., when the residual mesonephric ducts are still found in the lower part of the body of the uterus. The paramesonephric ducts develop on the lateral surface of the mesonephroi and by the 45th day p.c., differentiate into the uterine tubes and the uterus. The arrangement of the paramesonephric ducts in the abdominal cavity changes from the U- to the V-shaped system. The final topography of the uterine tubes is established between the 54th and 60th day p.c., as the uterine tubes become convoluted. Before the 54th day p.c., the uterine horns undergo rapid elongation and convolution, forming the W-shaped system. By the third month of postnatal life, the uterine horns become straight, as in the adult cat.

Light microscopy and scanning electron microscopy study on microstructure of gallbladder mucosa in pig.

The present light microscopy (LM) and scanning electron microscopy (SEM) studies on porcine gallbladder mucosa provide a description of the microstructures of great functional importance such as mucosal folds, the epithelium, glands, and lymphatic nodules. The results showed the regional structural differences of the porcine gallbladder wall. Depending on the part of the gallbladder, three types of mucosal structures were described: simple and branched folds and mucosal crypts. An important structural feature found in the mucosa is connected with the structural variety of type of mucosal folds, which change from simple located in the neck, to most composed, i.e., branched or joined, in the polygonal crypts toward the fundus of the gallbladder. The morphometric analysis showed statistically significantly differences in the form and size of the folds and between the fundus, body, and neck of the gallbladder. Differences in the size of mucosal epithelium are discussed in terms of processes of synthesis and secretion of glycoproteins. Regional, species-specific differences in morphology of mucosal subepithelial glands, i.e., their secretory units and openings, and intensity of mucus secretion were described. Our results on the pig gallbladder show adaptation and/or specialization in particular areas of the mucosa for (1) secretion of mucus in the neck or body of gallbladder and (2) for cyclic volume changes, especially in the fundus of gallbladder. The description of the microstructures of mucosa in the porcine gallbladder could be useful as reference data for numerous experiments on the bile tract in the pig.

Angioarchitecture of gallbladder in pig: LM and SEM study on vascular microcorrosion casts.

The study focused on the description of pig gallbladder angioarchitecture, with particular emphasis on the specifics of the course of blood vessels in individual layers of the gallbladder wall. Furthermore, the vascular systems of the pig gallbladder were analyzed in terms of the adaptation of this organ to changes in its volume during cyclical bile storage and discharge. The gallbladder is supplied by the cystic artery, which in the pig represents a mixed pinnate and bipinnate pattern of branching. The light microscopic and scanning electron microscopic observations of three-dimensional vascular corrosion casts showed the presence of two main complex vascular networks in the wall of the gallbladder, one located in the subserosal and the other in the mucosa. The unique features in the pig, connected with the size of the gallbladder, is the well-developed horizontal venous plexus under folds of the mucosa, which is a voluminous reservoir of fluids absorbed from bile and vascular networks around mucous glands. Superficial blood vessels of the gallbladder run in vascular pairs or triads, where a single artery runs between two veins. The structures of blood flow control, that is, venous valves, were observed only in venules of the subserosal plexus. Spatial arrangement of the vascular network in the pig gallbladder shows functional plasticity during changes in gallbladder volume. The course of superficial blood vessels in the well-filled gallbladder is arcuate, while in the empty gallbladder it is undulated or spiral. In the mucosal and intramural vessels the direction of blood vessels may change from perpendicular to oblique.

Testicular disorder of sex development in four cats with a male karyotype (38,XY; SRY-positive).

The molecular background of disorders of sex development (DSD) in cats is poorly recognized. In this study we present cytogenetic, molecular and histological analyses of four cats subjected for the analysis due to ambiguous external genitalia. Three cases, with rudimentary penises and an abnormal position of the urethral orifice, represented different types of hypospadias. The fourth case had a normal penis, a blind vulva and spermatogenetically active testes. Histological studies showed structures typical of testes, but spermatogenic activity was observed in two cats only. All the cats had a normal male chromosome complement (38,XY) and the Y-chromosome linked genes (SRY and ZFY) were also detected. Fluorescent in situ hybridization (FISH), with the use of the feline BAC probe harboring the SRY gene, excluded the possibility of chromosome translocation of the Y chromosome fragment carrying the SRY gene onto another chromosome. Sequencing of four candidate genes (SRY--sex determining region Y; AR--androgen receptor; SRD5A2--steroid-5-alfa reductase 2 and MAMLD1--mastermind-like domain containing (1) revealed one SNP in the SRY gene, one common polymorphism in exon 1 of the AR gene (tandem repeat of a tri-nucleotide motif--CAG), six polymorphisms (5 SNPs and 1 indel) in the SRD5A2 gene and one SNP in the MAMLD1 gene. Molecular studies of the candidate genes showed no association with the identified polymorphisms, thus molecular background of the studied DSD phenotypes remains unknown.

The development of the tongue of the domestic goose from 9th to 25th day of incubation as seen by scanning electron microscopy.

The general development of the tongue in birds was described by Lillie (1908) in chicken. Bryk et al. (1992) also studied the tongue development in chicken and they observed development of the conical papillae of the body. Our study aims to describe the timing of the development of the tongue morphological features in the domestic goose by using SEM methods. The tongue of the domestic goose is characterized by the widest variety of shape of the particular part of the tongue and mechanical papillae. Results indicated that the formation of the apex, body, lingual prominence, and the root of the tongue take place between the 10th and 19th day of incubation. The tongue elongates rapidly between the 16th and 18th day of incubation. Simultaneously, the median groove appears on the body and the lingual prominence and elongates towards the rostral part of the tongue. The conical papillae of the tongue develop gradually. On the body, the conical papillae develop from the caudal part of the body to the rostral part and on the lingual prominence from the median part of the prominence to the lateral part. Hair-like papillae at the caudal surface of the body of the tongue remain primordial to the end of the incubation. Our studies on the morphogenesis of the tongue in the domestic goose revealed changes in shape of the particular part of the tongue and rapid pace of the formation of mechanical papillae. The tongue is completely develop before hatching and ready to collect food.