Immunocytochemistry of paraneurons in the female urethra of the horse, cattle, sheep, and pig.

The aim of this study is to describe the presence of neuroendocrine (NE) cells (paraneurons), producing biogenic amines and/or peptidergic hormones, in the female urethra of cattle, sheep, pigs, and horses, by means of histochemical and double labeling immunofluorescent techniques. 5-Hydroxy-tryptamine-, chromogranin A-, cholecystokinin- and somatostatin-containing NE cells are present in the urethral epithelium of all the species studied, with the unique exception of the lack of somatostatin cells in the horse. Paraneurons containing 5-hydroxytryptamine colocalized with chromogranin A or cholecystokinin were also found in all subjects. Such active substances are hypothesized to play a role in the contraction of the urethral musculature, emission of urogenital fluids, and inhibition of endocrine and exocrine secretions.     

Scanning electron microscopic observation of apical sites of open-type paraneurons in the stomach, intestine and urethra.

The apical region of open-type paraneurons in tubular organs functions as a receptor site for chemical information in the lumen. Electron microscopic studies have demonstrated a tuft of microvilli on the luminal surface of cells, but failed to visualize it three-dimensionally. The present scanning electron microscope (SEM) observation succeeded in viewing, from the luminal side, open-type paraneurons distributed in epithelia of the stomach, intestine, and urethra. The pyloric antrum of avian species and the duodenum of human fetuses, the latter forming an endocrine cell colony at every villus tip, were chosen for SEM observation in order to eliminate visual obstruction by adjacent epithelial cells with developed microvilli. The luminal surface of gut endocrine cells was consistently covered with a tuft of 80-200 microvilli. Pyloric paraneurons possessed thick and stiff microvilli as compared with those of exocrine cells. The microvilli on intestinal paraneurons were more irregular in length and more loosely grouped than those composing the striated border of enterocytes. Urethral paraneurons containing serotonin were surrounded by three or four polygonal epithelial cells. Their narrow apical surface was provided with 30-100 microvilli which varied in length from cell to cell, and which were conspicuously projected above the luminal surface of the urethra. The microvillous crown of the gut and urethral paraneurons was so prominent and constant a structure on the apical surface as to allow easy identification of open-type paraneurons under the SEM.     

Analysis of the horse V(H) repertoire and comparison with the human IGHV germline genes, and sheep, cattle and pig V(H) sequences

We have constructed a chimeric antibody single-chain Fv (scFv) fragments phage-displayed library that combines an invariant human V(L) chain with the repertoire of V(H) domains amplified from a horse immunized against scorpion venom. To gain insight into the equine V(H) repertoire, the V(H) sequences of 46 unique clones randomly chosen from the library prior to antigenic selection were analyzed. Comparisons with previously reported equine V(H) sequences, as well as with the repertoire of human IGHV germline genes and known V(H) sequences of sheep, cattle and pig, suggest that the equine IGH locus harbors at least three IGHV gene families. Two families belong to clan II while the other was classified into clan I. The horse sequences were also found to encode a diverse repertoire of canonical structures. The most populated equine IGHV gene family, named IGHV1, and another family termed IGHV3, encode two out of the three canonical structures so far described for CDR1. The IGHV2 gene family has the third canonical structure at CDR1. In CDR2, nine loop lengths were found, with four of them matching the pattern of typical canonical structures. The remaining five CDR2 loop lengths are shorter or longer than those reported for human IGHV germline genes and known sequences of sheep, cattle and pig. The analysis of CDR3 loops indicates a length distribution broader than previous reports for horses; being similar to that of humans, sheep and pigs. Moreover, equine CDR3 loops were found to have a combination of lower content of cysteine and higher proportion of glycine not seen in the other species. This implies less constrained loops and therefore more apt for searching the conformational space of antigen-binding sites. Altogether, these findings reveal a more diverse perspective of the horse V(H) repertoire than previous estimations and lay foundations for future studies of the equine IGH locus.     

Microvascularization of the female urethra in fetuses,neonates and infants

The microvascularization of the female urethra was studied in fetuses, neonates and infants by injection of agarized China ink into the circulation. The purpose of this study was to specify the angioarchitecture of each tunic and their specific drainage. The disposition of the microvascularization of the urethra is superimposed on the orientation of the fibers of the muscular tunic. The orientation of the veins of the sub-mucous tunic is longitudinal and not plexiform.     

Distribution of retinal ganglion cells in five mammalian species (pig, sheep, ox, horse, dog)

Summary In order to ascertain shape and location of the central area, the distribution of ganglion cells was measured in whole mounts of the retina from pig, sheep, ox, horse, and dog. Although exact comparison of corresponding points of measurement in different animals was not possible, the measurements allowed the mapping of retinal ganglion cell density, typical for the particular species. In all ungulates a streak of high cell density extends along a straight horizontal line, dorsal to the optic disc. As a rule a maximum of ganglion cell density is found close to the temporal end of the visual streak. In the dog a well demarcated oval portion of the streak continues into a short temporal (variable) and a long nasal linear arm. The functional significance of these findings is discussed.

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Zusammenfassung Verteilung der Ganglienzellen in der Retina bei fünf Säugerarten (Schwein, Schaf, Rind, Pferd, Hund).Um Form und Lokalisation der Area centralis festzulegen, wurde an Ganzpräparaten der Retina von Schwein, Schaf, Rind, Pferd und Hund die Verteilung der Ganglienzellen ermittelt.Obgleich die Zahlenwerte in topographisch einander entsprechenden Punkten der Retina keinen genauen Vergleich erlauben, konnte die Ganglienzelldichte in der für die jeweilige Spezies typischen Verteilung dargestellt werden.Bei den untersuchten Ungulaten erstreckt sich oberhalb der Papilla optica ein horizontaler Streifen hoher Zelldichte. Im temporalen Ende dieser Area striaeformis findet sich regelmäßig eine besonders hohe Zahl von Ganglienzellen.Beim Hund schließt sich an einen ovalen Teil der Area centralis ein kurzer temporaler (nicht in allen Fällen nachweisbar) und ein längerer nasaler streifenförmiger Bezirk hoher Zelldichte an. Auf die funktionelle Bedeutung dieser Befunde wird hingewiesen.

     

Primary adenocarcinoma of the female urethra.

Three cases of primary adenocarcinoma of the female urethra are presented. The tumour in the first case was associated with urethritis glandularis and is thought to arise from previous glandular metaplasia of the urethral mucosa. The tumour in the second case resembled the clear-cell carcinomas of the lower female genital tract and is thought to be of embryonic rest origin. The tumour in the third case is thought to arise from the paraurethral glands.     

Histology of the canine urethra. I. Morphometry of the female urethra

Urinary bladders and urethrae were collected from six adult and two juvenile female dogs. Five urethral regions and the neck and body of the bladder were sampled. Volume fractions for connective tissue including elastic fibers, smooth and striated muscle, and epithelium were obtained by projecting section images onto an array of points and computing the number of points overlying a tissue constituent per total points overlying the tissue section. Smooth muscle occupied approximately half the volume of the bladder wall, one-third the volume of the vesical neck, and one-fourth the volume of the proximal urethra. Striated muscle was present in the distal half of the urethra, where the total muscle coat occupied about one-third of the urethral wall volume. Smooth muscle was practically absent in the terminal urethra, where the striated urethralis muscle encircles urethra and vagina in common. Epithelial area and lumen perimeter were not significantly different along the length of the urethra except that urethral epithelium was significantly thicker adjacent to the vesical neck. In terms of histological proportions, the vesical neck was intermediate between the body of the bladder and the proximal urethra.     

Osteocyte lacuna population densities in sheep, elk and horse calcanei

Osteocytes, the most prevalent cell type in bone, appear to communicate via gap junctions. In limb-bone diaphyses, it has been hypothesized that these cellular networks have the capacity to monitor habitual strains, which can differ significantly between cortical locations of the same bone. Regional differences in microdamage associated with prevalent/predominant strain mode (tension, compression, or shear) and/or magnitude may represent an important "variable" detected by this network. This hypothesis was indirectly addressed by examining bones subjected to habitual bending for correlations of osteocyte lacuna population densities (n/mm(2) bone area, Ot.Lc.N/B.Ar) with locations experiencing high and low strain, and/or prevalent/predominant tension, compression, and shear. We examined dorsal ("compression"), plantar ("tension"), and medial/lateral ("shear" or neutral axis) cortices of mid-diaphyseal sections of calcanei of adult sheep, elk, and horses. Ot.Lc.N/B.Ar data, quantified in backscattered electron images, were also evaluated in a context of various additional structural and material variables (e.g. % ash, cortical thickness, porosity, and secondary osteon population). Results showed significant differences in dorsal versus plantar comparisons with the highest Ot.Lc.N/B.Ar in dorsal cortices of sheep and elk (p < 0.0001); but this was a statistical trend in the equine calcanei (p = 0.14). There were no consistent transcortical (pericortical to endocortical) differences, and Ot.Lc.N/B.Ar in neutral axes was not consistently different from dorsal/plantar cortices. Correlations of Ot.Lc.N/B.Ar with structural and material parameters were also poor and/or inconsistent within or between species. These results provide little or no evidence that the number of osteocyte lacunae has a functional role in mechanotransduction pathways that are typically considered in bone adaptation. Although dorsal/plantar differences may be adaptations for prevalent/predominant strain modes and/or associated microdamage, it is also plausible that they are strongly influenced by differences in the bone formation rates that produced the tissue in these locations.     

Regional distribution of alpha-adrenoceptor subtypes in the female rabbit urethra

The aim of the present investigation was to study the regional distribution of alpha-adrenoceptor subtypes in the female rabbit bladder base and urethra, using radioligand binding and mechanical activity studies. The binding studies performed on membranes prepared from the bladder base, and the proximal and distal part of the urethra, revealed that the number of alpha 1-adrenoceptors did not significantly differ between the three regions, whereas the number of alpha 2-adrenoceptors increased distally. The mechanical activity studies showed that noradrenaline and clonidine, but not phenylephrine, were more potent in the distal than the proximal part of the urethra. It is suggested that in the female rabbit urethra the lower EC50-value found for noradrenaline and clonidine in the distal as compared to the proximal part of the urethra, at least in part, is attributable to a higher number of postjunctional alpha 2-adrenoceptors in the distal than in the proximal urethra.     

Influence of antimuscarinics on alpha-adrenoceptors in the female rabbit urethra

The effects of the tertiary amine atropine and its structural analogues homatropine and scopolamine, as well as the quarternary amine emeprone, were evaluated on noradrenaline (NA)-induced contractions of isolated female rabbit urethral ring preparations. In addition, the abilities of these antimuscarinics to inhibit ³H—dihydro—alpha—ergocryptine (³H—DHE) binding to alpha—adrenoceptors were studied on a crude membrane preparation from the female rabbit bladder base and urethra. Atropine and homatropine depressed the NA- induced contractions in a concentration-dependent way, whereas this was not seen with scopolamine. Emeprone 10^-5 10^-4 M augmented the contractions, an effect possibly attributable to a NA-uptake blocking effect. All antimuscarinics displaced specific ³H— DHE binding, the order of potency being atropine>homatropine>emeprone>scopolamine. In general a good correlation was seen between the binding and mechanical activity studies for atropine, homatropine and scopolamine, while this was not found for emeprone. It is concluded that alpha-adrenoceptor blockade by atropine can be observed at concentrations exceeding 10^-7 M. Scopolamine, showing alpha-adrenoceptor blocking properties only in high concentrations, may be used as an alternative for blockade of muscarinic cholinoceptors.