Influence of naturally unilateral cryptorchidism on the histomorphometry of the testes and daily sperm production in West African Dwarf goats.

Quantitative histology of the descended testis of unilateral cryptorchid bucks was compared with testis of normal bucks to evaluate the reproductive potentials of the scrotal testis in unilateral cryptorchids, using light microscopy techniques. The contralateral scrotal testes of the unilateral cryptorchids and the testes of the normal bucks contained profiles of seminiferous epithelium and each showed histological evidence of normal activity. The mean heights, lengths, lumen diameter, diameter of the seminiferous tubules were significantly higher in the contralateral scrotal testes when compared to the retained testes of the unilateral cryptorchid bucks (P<0.05). Population of spermatogenic cells per testis, and ratio of germ cells to Sertoli cells were not significantly different between both groups. The percentage of the testes occupied by various germ cells did not differ between the scrotal testis of the cryptorchid bucks and those of the normal bucks. The volume occupied by the seminiferous tubules and Leydig cells in the contralateral scrotal testis of the unilateral cryptorchid bucks were significantly greater than those of the testis of normal bucks (P<0.05). From the findings, it appears that the spermatogenic efficiency of the scrotal testes of the unilateral cryptorchid bucks was significantly higher than those of the normal bucks.

Sonographic Biometry of Normal Kidney Dimensions among School-age Children in Nsukka, Southeast Nigeria.

BACKGROUND: Some kidney diseases are usually associated with changes in kidney size. OBJECTIVE: To determine sonographically the normal limits and percentile curves of the kidney dimensions according to age, gender and somatometric parameters among school-age children. METHODS: A prospective cross-sectional research design and convenience sampling method were utilized. Participants included 947 normal subjects (496 boys and 451 girls) aged 6-17 years old. The sonographic examination was performed on a Shenzhen DP-1100 machine with 3.5 MHz convex transducer. Longitudinal and transverse dimensions of the kidneys were obtained in coronal plane with the subject in the supine or left lateral decubitus position. RESULTS: The means of right and left kidney lengths in mm were 79.6 ± 8.1 and 81.6 ± 8.3, respectively while that of the right and left kidney widths in mm were 35.03 ± 3.6 and 35.09 ± 3.6, respectively. Dimensions of the kidneys were not statistically different in boys and girls (p > 0.05). There was a statistically significant difference between right and left kidney length (p < 0.05). Height correlated best with both kidney lengths. Thus the normal limits, prediction models and percentile curves of kidney lengths were established with respect to height. CONCLUSION: Sonographic determination of pathologic changes in the size of the kidneys necessitates knowing the normal ranges of its lengths especially with respect to height in school-age children.

Sonographic determination of spleen to left kidney ratio among Igbo school age children of south east Nigeria.

BACKGROUND: Clinical determination of mild splenomegaly is notoriously inaccurate. OBJECTIVES: To determine sonographically the spleen to left kidney ratio according to age and somatometric parameters among school age children in a tropical environment. METHODS: A cross sectional study and convenience sampling were done on 947 apparently healthy subjects (496 boys and 451 girls) aged 6-17 years at the University of Nigeria Medical Centre, Nsukka. The sonographic examination was performed on Shenzhen DP-1100 machine with 3.5 and 5 MHz convex transducers. Spleen and left kidney lengths were obtained using appropriate techniques. The weight and height of the subjects were obtained with the participants wearing light weight street clothes without shoes. RESULTS: Measurement of spleen and left kidney lengths were reliable within and between sonographers. The spleen and left kidney lengths were not statistically different in boys and girls (p > 0.05). The spleen to left kidney ratio according to age and somatometric parameters is constant at about 1.13 with 1.3 as the upper limit of normal in the studied population. CONCLUSION: Sonography can be used to detect mild splenomegaly if the spleen to left kidney ratio is greater than 1.3 in the absence of renal disease among school age children.

Sonographic biometry of spleen among school age children in Nsukka, Southeast, Nigeria.

BACKGROUND: Normative value of spleen size among school age children is important for objective assessment of the spleen. OBJECTIVES: This study was aimed at determining sonographically the normal limits of the spleen size according to age, sex, and somatometric parameters among school age children. METHODS: A cross sectional study was done on 947 apparently healthy subjects (496 boys and 451 girls) aged 6 - 17 years. The subjects were recruited from some primary and secondary schools within Nsukka metropolis and also from out patients in the study centre. A pilot study was done to determine the intra- and inter rater reliability of sonographic measurements of the spleen. The sonographic examination was performed on Shenzhen DP-1100 machine with 3.5 and 5 MHz convex transducers. Spleen sizes were obtained with the subject in a right lateral decubitus position. RESULTS: Measurement of spleen length was reliable while measurement of spleen width was less reliable within and between sonographers. Dimensions of the spleen were not statistically different in boys and girls (p > 0.05). Height correlated best with spleen dimensions. CONCLUSIONS: Normogram of the spleen size with respect to height is important in the determination of some pathology associated with changes in its size.

Morphological assessment of placentomal trophoblastic epithelium in the placenta of West African Dwarf goats: a light and electron microscopic study.

Gravid uteri harvested from 11 pregnant West African Dwarf goats at different stages of gestation were used to study the morphology of goat placentomal trophoblastic epithelium. The trophoblastic epithelium was composed of two trophoblast cell types; the mononucleate trophoblast cells and the binucleate trophoblast cells. Mononucleate trophoblast cells were tall columnar cells that rested on the basal lamina and extended to the foetomaternal interface, where their microvillar processes interdigitated with similar processes of the uterine epithelial cells to form the foetomaternal contact zone. Mononucleate trophoblast cells lining the arcade zones of placentomes contained erythrocytes in their cytoplasm. These cells are morphologically modified for acquisition of nutrients from the maternal compartment. Binucleate trophoblast cells showed two nuclei per cell and numerous characteristic membrane-bound granules in their cytoplasm. In addition, the binucleate cells resided in an intraepithelial position, showed evidence of capacity to migrate within the trophoblastic epithelium and fused with uterine epithelial cells at the foetomaternal interface. It would appear that the roles of the binucleate cells include formation of foetomaternal-derived hybrid cells in the placentomes and translocation of foetally synthesized substances across the placental barrier into maternal tissues via their migration and fusion with uterine epithelial cells. Furthermore this study demonstrated morphological modifications of the placentomal trophoblastic epithelium including extension of foetal blood capillaries into an intraepithelial position within the trophectoderm, such that they are situated close to the foetomaternal contact zone. This may enhance haemotrophic exchange of nutrients and metabolites between maternal and foetal blood circulations by reducing the diffusion distance between foetal and maternal blood capillaries.

Morphologic features of lymph vessels in caprine hemal nodes.

The distribution and characteristics of lymph vessels in caprine hemal nodes were studied after glutaraldehyde fixation and epoxy resin embedding. Histologically, the lymph vessels were characterized by thin walls and wide lumens containing inspissated lymph in which a few cells were suspended. The lymph vessels contrasted sharply with adjacent blood sinuses that were filled with elements of circulating blood. A circumferential lymph vessel in the cortex joined radial branches in the medulla that met at the hilum to drain through a large efferent lymph channel. Ultrastructurally, the lymph vessel wall comprised endothelial cells supported by a continuous basal lamina, collagen fibrils, and adventitial reticular cells. The cytoplasm of endothelial cells had fenestrations, plasmalemma-associated vesicles, vacuoles, and focal splits that enclosed large compartments. Many compartments contained erythrocytes and lymphocytes. Modifications of the endothelial cells signified their endowment with features that favored transendothelial transport. The distribution of lymph vessels and the finding of only efferent lymph channels are related to the roles of hemal nodes in blood storage by hemoconcentration and in immune defense mechanisms.

Erythrophagocytosis in the caprine hemal node.

Caprine hemal nodes were studied by transmission electron microscopy after glutaraldehyde fixation and epoxy resin embedding. Hemal node macrophages were observed to be engaged in erythrophagocytosis. In the early stages of endocytosis, intact erythrocytes were contained in some of the heterophagic vacuoles of macrophages. Later, granular, electron-dense material appeared on erythrocytes, presumably as a result of lysosomal degradation of their matrices. Subsequently, the matrix fragmented and probably formed 'myelin-like figures' and residual bodies that dominated the macrophage cytoplasm. In addition, images of sinusoidal endothelium, reticular cells, lymphocytes and, rarely, eosinophils were observed that depicted structures resembling various stages of lysosomal digestion of erythrocyte matrix noted in macrophages. Our study provides evidence to support the fact that effete erythrocytes are filtered, besides known organs, also in caprine hemal nodes. The morphology and location of hemal nodes suggest that the organ can be an efficient blood filter.

Histology of the caprine hemal node.

Caprine hemal nodes were studied by light microscopy after glutaraldehyde fixation and epoxy resin embedding. A node consisted of a capsule, subcapsular and other sinuses, cortex, medulla and hilus. Elements of circulating blood filled the interstices of the reticular meshwork and associated macrophages which traversed the lumina of subcapsular and medullary sinuses. The latter were rare in 1-month-old goats, progressively increased in number and size in 2- to 4-month-old goats and coalesced with each other and the subcapsular sinus in adult animals. The cortical tissue appeared as lymphoid nodules. Circumferential lymphatic vessels abutted on outer margins of the nodules and gave origin to several radial lymphatics which branched and anastomosed between the medullary blood sinuses. Medullary cords were organized around the radial lymphatics. A single efferent lymphatic was formed at the hilum by confluence of the radial lymphatics. Our study, in contrast to earlier reports, shows that caprine hemal nodes possess efferent lymphatics. The present data suggest that the hemal nodes are involved, in addition to classical functions, in blood storage by hemoconcentration.

Fine structure of boundary tissue of the seminiferous tubules in the scrotal and abdominal testes of naturally unilateral cryptorchid West African dwarf goats.

The boundary tissue of the seminiferous tubules in the scrotal and abdominal testes of naturally unilateral cryptorchid West African dwarf goats comprised an inner non-cellular, a middle cellular and peripheral cellular lamellae. In the scrotal testes, these components were compact and their arrangement conformed to that described for other domestic ruminants except that here, the basal lamina associated with the seminiferous epithelium was homogeneous and in tact. Alterations due to cryptorchidism as observed in the contralateral abdominal testes include general loss of compactness due to depletion and disorganization of structural extracellular materials like basal lamina coat of myoid cells and collagen fibrils, the splitting of the basal lamina of the seminiferous epithelium into 8-12 thin layers, poor differentiation of the myoid cells and the accumulation of lipid droplets within their cytoplasm. It is concluded that the normal caprine boundary tissue conforms entirely to the characteristics of 'Type C' category in the existing classification. The ultrastructural alterations due to abdominal retention of the testis resemble the testicular changes ascribed to the disturbance of pituitary-testicular hormonal axis.

Morphologic features of Sertoli cells in the intra-abdominal testes of cryptorchid dwarf goats.

Light and electron microscopy revealed an age-related progression of alterations of Sertoli cells in the intra-abdominal and scrotal testes of unilaterally cryptorchid West African dwarf goats between the ages of 1 and 30 months. Alterations in the scrotal testis were, however, maturational and included differentiation of Sertoli-to-Sertoli cell junctional specializations, profusion of smooth endoplasmic reticulum, convolution of nuclear profiles, development of vacuolar components of the nucleolus, and an overall change in cell shape in response to proliferation of germinal cells. Corresponding features were observed in Sertoli cells of the contralateral intra-abdominal testis, but the cytoplasmic features were transient because the cells degenerated progressively. Early changes included segregation of the smooth endoplasmic reticulum into compact masses composed of dense, narrow cisternae, dilatation of the rough endoplasmic reticulum cisternae into large, irregular profiles, atrophy of the Golgi complex, and accumulation of lipid droplets and lipofuscin granules. Many of these organelles and inclusions no longer were obvious in Sertoli cells of 12- to 15-month-old goats; rather, intracellular vacuoles and dilated intercellular spaces had become common. In the 24- to 30-month-old goats, Sertoli cells in the intra-abdominal testis contained mostly microfilaments and basally located mitochondria with circular cristae in dense matrices. The Sertoli-to-Sertoli cell junctional specializations were structurally intact. These results indicated that, in spite of the unfavorable intra-abdominal environment, Sertoli cells of the intra-abdominal testis, before their degeneration, had developed features similar to those of the scrotal testis.

Ultrastructural observations on the terminal segment epithelium of the seminiferous tubule of West African dwarf goats.

In the testes of West African dwarf goats, modified Sertoli cells comprise the major component of the terminal segment epithelium. They resemble Sertoli cells proper but differ in the paucity of agranular endoplasmic reticulum and lipid droplets. Cell attachment devices present include rudimentary desmosomes and occasional multiple contacts of opposing plasma membranes, interrupted by segments of slightly expanded intercellular space. A few generative cells are present in the proximal zone of the epithelium, but their development appears to terminate as early spermatids which hang loosely on the luminal surface. The middle zone epithelium comprises vacuolated cells lying among other cells containing abundant microtubules in their subapical cytoplasm. Globular expansions of the intercellular space are also apparent. The terminal plug contains two cell types. Type I are inclined, columnar cells which contain profuse arrays of agranular endoplasmic reticulum in their apical cytoplasm. Type II are smaller cells located at the apex of the plug. Each possesses cytoplasmic processes, which surround the apices of Type I cells. The modified Sertoli cells of all zones and the Type II plug cells contain remnants of spermatozoa at different stages of degradation. The general absence of developing generative cells in the terminal segment epithelium may be related to the paucity of agranular endoplasmic reticulum in the basal cytoplasm of modified Sertoli cells and the absence of typical Sertoli-Sertoli junctional specialisations. Structural modifications evident in the middle and distal zones facilitate distalward movement of materials, while the attenuation and modification of the lumen distally may facilitate phagocytosis of abnormal spermatozoa.

Light and electron microscopical observations on the Leydig cells of the scrotal and abdominal testes of naturally unilateral cryptorchid West African dwarf goats.

The structure of interstitial cells of Leydig in the scrotal and abdominal testes of adult West African dwarf goats was studied utilising light and electron microscopy. The Leydig cells in both testes were scattered singly, in cords or clusters in the intertubular connective tissue in close proximity to vascular elements. The intertubular connective tissue in the abdominal testes was however much wider because of the hypoplasia of the seminiferous tubules. While the cells of the scrotal testes exhibited non-granular, pale staining cytoplasm, those of the abdominal testes were darkly staining and the majority contained coarse intracytoplasmic osmiophilic granules Interspersed amongst these cells were adipose cells occasionally distributed overall. With the electron microscope, it was found that agranular endoplasmic reticulum, Golgi apparatus and mitochondria were more prominently developed in the scrotal testes. In marked contrast, there were numerous lipid droplets in the cytoplasm of the Leydig cells in the abdominal testes. Furthermore, the cytoplasm of several of these cells showed evidence of degeneration. It is concluded that, contrary to observations in the experimentally induced condition, abdominal retention of testes in natural unilateral cryptorchidism induces alterations in the light microscopical and ultrastructural features of the Leydig cells of West African dwarf goats, changes which possibly can be ascribed to the chronic decline in testicular blood flow and the elevated temperature of the abdominal environment.

Light and electron microscopic studies on the oesophageal epithelium of the rainbow trout, Salmo gairdneri.

The oesophageal epithelium of the rainbow trout, Salmo gairdneri, showed a gradual transition from stratified cuboidal type containing mainly filament-containing cells and globular Type I mucous cells anteriorly to a simple columnar type composed entirely of Type II mucous cells distally. Taste buds were present in the anterior portion; mucous glands were located in the lamina propria in the middle portion and these were replaced with gastric-type glands in the terminal portion. Type I mucous cells severally produced neutral, carboxylated and sulphated mucosubstances while each Type II cell produced all the three types of mucosubstance. In the higher layers of the anterior multilaminar epithelium, the cytoplasm of the filament-containing cells contained numerous small vesicles with cores of flocculent material and the luminal aspects of the surface cells bore microridges. The vesicles contained in Types I and II mucous cells differed in size, arrangement and mode of release. These findings suggest that there is maximal development of protective features, both structural and lubricatory , which aid the oesophagus in the conduction of food materials. Additional sensory and digestive functions are also indicated.

Fine structural studies on the myenteric plexus of the gastro-intestinal tract of the rainbow trout (Salmo gairdneri, Rich.).

The neuronal elements is most part of the myenteric plexus of the gastro-intestinal tract of the Rainbow trout consisted of nerve cell bodies and unmyelinated nerves successively invested by satellite and Schwann cells respectively, thin basal lamina, a layer of collagenous fibrils and interstitial cells, the processes of which were often held together by desmosomes. These were embedded in a loose vascular connective tissue. Encapsulated vagal nerve trunks formed a part of the myenteric plexus in the region of the stomach and they contained similar elements in the same order and, in addition, myelinated nerve fibres. Four subtypes of small neurons and two of large neurons were distinguished based on the presence and varying pattern of organization of cytoplasmic organelles. Five types of neuronal processes and several plasma membrane specializations were described and these were involved in the formation of axo-dendritic and axo-somatic synapses. Three main types of axon varicosities were also distinguished according to their vesicular contents. The significance of these findings is discussed and attempt is made to correlate them with existing experimental and histochemical information on teleost gut.

Micromorphological observations on the nervous elements in the rectal mucosal folds of the rainbow trout (Salmo gairdneri, Rich.).

Light and ultrastructural characteristics of the nervous elements in the cores of the rectal mucosal folds of the Rainbow trout (Salmo gairdneri, Rich.) are described. The elements comprised occasional nerve cell bodies and many axons, most of the varicosities of which contained large numbers of large granular vesicles (90...120 nm in diameter) and small electronlucent vesicles (40...60 nm in diameter). Very frequent individual relationships between the fibres of the muscularis mucosae and the axon varicosities were noted. These findings are correlated with the functions of this part of the gut and their general significance in teleost gut innervation is discussed.

Ultrastructural observations on the submucous plexus of the large intestine of the rainbow trout (Salmo gairdneri, Rich.).

Ultrastructural studies on the large intestine of the Rainbow trout revealed the hitherto unreported presence of neurons within the submucous plexus. The neurons were closely associated with axons which expanded intermittently along their length to form varicosities. According to the type and proportion of vesicles within the varicosities, three groups were distinguished. Group I varicosities contained a predominant population of small electronlucent vesicles measuring 30 nm in diameter. Group II varicosities contained a few medium-sized granular vesicles measuring 60 nm in diameter mixed with large numbers of small electronlucent vesicles. Most of the Group III varicosities contained large numbers of large granular vesicles, 90 nm in diameter. Varicosities of all groups formed axosomatic synapses. The significance of the presence of neurons in the submucous plexus of the trout large intestine is discussed. Group I and II varicosity profiles were interpreted as representing cholinergic and adrenergic innervation respectively. The identification of the transmitter substance in Group III varicosities, however, has still to be resolved.