Cellular changes in the hamster testicular interstitium with ageing and after exposure to short photoperiod.

The aim of this study was to evaluate the cellular changes that occur in the hamster testicular interstitium in two very different physiological situations involving testicular involution: ageing and exposure to a short photoperiod. The animals were divided into an 'age group' with three subgroups - young, adult and old animals - and a 'regressed group' with animals subjected to a short photoperiod. The testicular interstitium was characterised by light and electron microscopy. Interstitial cells were studied histochemically with regard to their proliferation, terminal deoxynucleotidyl transferase (TdT)-mediated dUTP in situ nick end labelling (TUNEL+) and testosterone synthetic activity. We identified two types of Leydig cell: Type A cells showed a normal morphology, while Type B cells appeared necrotic. With ageing, pericyte proliferation decreased but there was no variation in the index of TUNEL-positive Leydig cells. In the regressed group, pericyte proliferation was greater and TUNEL-positive cells were not observed in the interstitium. The testicular interstitium suffered few ultrastructural changes during ageing and necrotic Leydig cells were observed. In contrast, an ultrastructural involution of Leydig cells with no necrosis was observed in the regressed group. In conclusion, the testicular interstitium of Mesocricetus auratus showed different cellular changes in the two groups (age and regressed), probably due to the irreversible nature of ageing and the reversible character of changes induced by short photoperiod.

Cell proliferation in the seminiferous and epididymal epithelia of Sus domesticus.

It is important to understand the proliferative activity of the different structures of the male reproductive apparatus in livestock species, such as Sus domesticus, to ensure reproductive efficiency. The main aims of this study were (a) to evaluate the proliferative activity of the spermatogonia in the different stages of the seminiferous cycle and (b) to study the cell proliferation in the epididymal epithelium in each region, identifying the different cells involved. For this, the testes and epididymis of three healthy, sexually mature Sus domesticus boars were used. The organs were processed for light microscopy, and immunohistochemical techniques were used to detect proliferating cell nuclear antigen. The cells immunostaining positively and negatively for proliferating cell nuclear antigen were counted and several parameters and indexes were calculated to evaluate the proliferation in both epithelia, taking into account the stage of the seminiferous epithelium cycle, and, in the case of the epididymal epithelium, the different regions and cells are the same. Finally, a contrast analysis of equality between pairs of means was carried out followed by a least significant differences test, in which differences were considered significant at P < 0.05. In the seminiferous epithelium, the greatest total number of spermatogonia and proliferating spermatogonia was observed in the postmeiotic stages (mainly VII and VIII). The proliferation index of the spermatogonia increased from the meiotic to postmeiotic stages. As regards the epididymal epithelium, the total proliferation index was higher in the caput. In each region, the clear and principal cells showed the highest proliferation index with respect to the total number of cells counted, whereas the proliferation index of each cell with respect to the same type was higher in the clear cells, followed by the narrow and principal cells. In conclusion, the proliferative activity of spermatogonia in the seminiferous epithelium of Sus domesticus is stage-dependent, and mainly occurs in the postmeiotic stages. In the epididymal epithelium, proliferative activity takes place in several cell types and is dependent on the anatomical region of the epididymis. We think that these results may be of importance for understanding the pathologic or reproductive processes in which cell proliferation is involved in the male reproductive system.

Histological changes in connective tissue of rat tails after bipolar radiofrequency treatment.

Radiofrequency (RF) has been included in the techniques used in aesthetic surgery/medicine. To date, no studies have performed a histological assessment of changes in the tissue after application of bipolar radiofrequency (BRF) with low energy and frequency. The aim of this study was to examine changes that are produced in connective tissue, principally in the fibroblasts, following BRF treatment. Four groups of rats received a different number of RF sessions (1, 2, 3 and 5). The following parameters were determined: the number of fibroblasts/unit area (FA), the proliferation index (PI), the Heat shock Protein 47 index (HSPI) and the percentage of connective tissue (PC). For statistical analysis, two subgroups (A and B) were made for the variables FA, PI and PC, and another two subgroups (C and D) for the variable HSPI. Significant differences for FA, PI and PC were observed between subgroups A and B, FA and PI having higher values in A, while PC had higher values in B. The HSPI in subgroup C showed significantly higher values than in D. Low energy and frequency BRF led to an increase in the number, proliferation and biosynthetic activity of fibroblasts. The resulting stress suffered by fibroblasts as a result of heat may be associated with the phenomenon of hormesis.

The acrosomic reaction in stallion spermatozoa: inductive effect of the mare preovulatory follicular fluid.

In the female genital tract, spermatozoa must undergo capacitation and acrosome reaction prior to fertilization. A number of factors may induce physiological acrosome reaction assayed in vitro. The aims of this study are to determine the inductive effect of the preovulatory follicular fluid on the sperm acrosomal status in the equine, once some characteristics of the follicular fluid during folliculogenesis had been evaluated. The spermatozoa were obtained from cauda epididymes of adult stallion. Follicular fluid was taken from mare ovarian follicles classified according to their diameter. In these fluids, total protein, progesterone, estradiol and osmolarity were determined. Afterwards, the effect of preovulatory follicular fluid (50%) upon induction of the acrosomic reaction in stallion capacitated spermatozoa was assayed. Results show that during folliculogenesis the ratio progesterone/estrogen is below 1. In large preovulatory follicles, there is a sharp increase of progesterone, reaching a ratio progesterone/estrogen close to 4. Protein concentration and osmolarity increase together with follicular development, being osmolarity very high at the preovulatory stage. Follicular fluid--in vitro--increases the percentage of spermatozoa with acrosome reaction, maintaining high rates of vitality and motility. The characteristics of follicular fluid undergo dynamic changes during the folliculogenesis, such as steroid level, protein concentration and osmolarity. These events may play a role in the reproductive process in vivo, considering that in vitro the follicular fluid is a very effective inductor of the acrosome reaction, with optimum levels of vitality and motility.

The acrosomic reaction in stallion spermatozoa: inductive effect of the mare preovulatory follicular fluid

In the female genital tract, spermatozoa must undergo capacitation and acrosome reaction prior to fertilization. A number of factors may induce physiological acrosome reaction assayed in vitro. The aims of this study are to determine the inductive effect of the preovulatory follicular fluid on the sperm acrosomal status in the equine, once some characteristics of the follicular fluid during folliculogenesis had been evaluated. The spermatozoa were obtained from cauda epididymes of adult stallion. Follicular fluid was taken from mare ovarian follicles classified according to their diameter. In these fluids, total protein, progesterone, estradiol and osmolarity were determined. Afterwards, the effect of preovulatory follicular fluid (50) upon induction of the acrosomic reaction in stallion capacitated spermatozoa was assayed. Results show that during folliculogenesis the ratio progesterone/estrogen is below 1. In large preovulatory follicles, there is a sharp increase of progesterone, reaching a ratio progesterone/estrogen close to 4. Protein concentration and osmolarity increase together with follicular development, being osmolarity very high at the preovulatory stage. Follicular fluid--in vitro--increases the percentage of spermatozoa with acrosome reaction, maintaining high rates of vitality and motility. The characteristics of follicular fluid undergo dynamic changes during the folliculogenesis, such as steroid level, protein concentration and osmolarity. These events may play a role in the reproductive process in vivo, considering that in vitro the follicular fluid is a very effective inductor of the acrosome reaction, with optimum levels of vitality and motility.

Genesis y uso del termino pre-embrion en la literatura cientifica actual / Present use of the term pre-embryo

Durante estos últimos años el debate sobre el carácter humana del embrión ha continuado. Uno de los hechos que pueden percibirse en este debate, contrariamente a lo que sucedió en los primeros anos, es el olvido sistemático de la palabra ®pre-embrión¼ para referirse al embrión preimplantatorio. En este trabajo, tras analizar el nacimiento de esta palabra y los intentos de dotarla de una conceptualización adecuada, describimos y constatamos mediante un sencillo estudio bibliométrico el poco éxito que ha tenido esta palabra así como el estancamiento de esta desde su aparición. En conclusión, no sólo se puede certificar la carencia conceptual de éste término, es decir, su no correspondencia con realidad alguna, sino también certificar a nivel fenomenológico el escaso uso de ella, con lo que también se avala el carácter artificial del término.

Morphological and histochemical study of human submucosal laryngeal glands.

BACKGROUND: The respiratory submucosal glands are a major source of secretions in the airway. Human submucosal laryngeal glands have been scarcely studied, with no works existing about their ultrastructure and histochemistry. METHODS: Samples of epiglottis, ventricle, false vocal folds and true vocal folds were fixed in 10% buffered formalin for histochemical study with conventional and carbohydrate lectin histochemistry. Other samples were fixed in 2.5% glutaraldehyde and conventionally processed for transmission electron microscopy. RESULTS: The human submucosal laryngeal glands are composed of serious tubules; mucous tubules; collector duct; and final portion of this duct. The serous cells showed sialosulphomucins and affinity for WGA and Con-A lectins. With a previous treatment with neuraminidase, they also labelled with PNA. The mucous cells contained sialosulphomucins and showed affinity for WGA and DBA lectins in the samples proceeding from blood group A, and for WGA, UEA-I and LTA with those from blood group O. Ultrastructurally, the serous cells presented a wide variety of granules, cells in which seromucous granules predominated. The mucous cells presented larger-sized granules which were very electron-lucent. The collector duct was composed of mitochondria-rich cells and basal cells. A cell which we have termed "intermediate" was identified in the transition zone between the mucous tubules and the collector duct, and in the final portion of the collector duct. It had morphological characteristics as if it were a transition between a goblet cell and collector duct cell. Some nerve endings with cholinergic and peptidergic vesicles were found among the myoepithelial cells. CONCLUSIONS: These glands presented some histological differences from the bronchial glands, the mucous secretion was related to the blood group antigens, and the serous cells showed a wide variability in their secretory granules, many of them being of a seromucous type.

Lectin histochemistry of the olfactory surface in two teleostean fishes.

A histochemical study on carbohydrate sequences in the epithelial surface of the olfactory organs in 2 teleostean species was carried out by means of lectins conjugated with peroxidase. At the same time, the distribution of the 2 kinds of epithelium are found, and the influence of decalcification with HNO3 in the pattern of reactivity to the lectins used were studied. The 2 components which reacted with the lectins were: 1. the apical surface of the olfactory epithelium, which was rich in L-mannose, N-acetyl-glucosamine, or sialic acid residues, and 2. the goblet cells which presented N-acetyl-glucosamine or sialic acid and N-acetyl-galactosamine. In neither site were found residues of L-fucose. The non-olfactory epithelium, where the goblet cells were located, showed signs of proceeding from a metaplasia of the olfactory epithelium. The decalcification in general terms supposed an intensification of the binding of the lectins to the tissues studied, and also the presence of new affinities which were not found without this treatment. In conclusion, the olfactory epithelium of these 2 teleostean fishes showed a rich layer of carbohydrates on its surface that is probably not only secreted by the goblet cells but also by the supporting cells.

Morphological study of the nasal conchae of the guinea pig.

The histology of the conchae of the nasal cavity in the guinea pig was investigated by means of conventional light and transmission electron microscopy. The results showed a clear structural difference between the anterior and the posterior portion of the conchae, being in the first zone where the vasculature was more numerous. The arterioles and the venules were richly innervated, abounding in cholinergic nerve endings with vesicles of probably peptidergic character. The glands were located in the posterior portion and were constituted by acini, an intercalated and a striated duct. Acini as well as the intercalated duct showed cholinergic nerve endings and vesicles with also a probably peptidergic character. In conclusion, the conchae of the nasal cavity of the guinea pig showed marked morphological differences in comparison with those of humans.

Comparative immunohistochemical study of the gastroenteropancreatic endocrine system of three reptiles.

The gastroenteropancreatic (GEP) endocrine system of three reptiles, Testudo graeca, Mauremys caspica, and Lacerta lepida, was investigated by means of immunocytochemistry. Single and double immunostaining methods have demonstrated immunoreactivity for insulin, glucagon, pancreatic polypeptide (PP), somatostatin, serotonin, and peptide tyrosine tyrosine (PYY) in endocrine cells of the pancreas of the reptiles studied. Islet-like structures with insulin-immunoreactive (IR) cells surrounded by glucagon-IR cells were observed only in the splenic portion of the pancreas of M. caspica. Occasionally, somatostatin- and PP-IR cells were associated with glucagon-containing cells. Endocrine cells were also observed in the excretory ducts of the exocrine glands. Serotonin, bombesin, neurotensin, gastrin, glucagon, somatostatin, PYY, and insulin were demonstrated immunocytochemically in open-type GEP cells of the digestive tract of the animals studied. Serotonin, somatostatin, and glucagon-immunoreactive cells were the most abundant endocrine cell types. In L. lepida, PP- and peptide tyrosine tyrosine-immunoreactive cells were also frequently observed. Cells containing cholecystokinin, gastric inhibitory peptide, met- and leu-enkephalin, motilin, secretin, and vasoactive intestinal peptide could not be detected. The present work demonstrates that the reptilian GEP endocrine system is a complex structure containing most of the regulatory peptides similar in structure to those found in higher vertebrates.

A light and electron microscopic study of the epithelium of the extrapulmonary airways of Mauremys caspica and Lacerta lepida (Reptilia).

The epithelium of the extrapulmonary airways of a Chelonia (Mauremys caspica) and a Squamata (Lacerta lepida) was investigated by means of conventional light and transmission electron microscopy, scanning electron microscopy, histochemistry and immunocytochemistry. The epithelium of Mauremys caspica is composed of basal, ciliated, endocrine and mucous cells. Serotonin-immunoreactivity was detected in the endocrine cells. Mucous cells were found to contain either sialo-mucins or both sialo- and sulphomucins. The extrapulmonary airways of Lacerta lepida were lined by an epithelium composed of basal, ciliated and secretory cells. No endocrine cells were detected. Secretory cells showed a different morphology to that observed in the mucous cells of Mauremys caspica suggesting a possible serous role for these cells. Migratory cells (plasma and mast cells, leucocytes and macrophages) and small intraepithelial nerves were also detected within the epithelium of both species. The present results show that marked morphological differences occur between the epithelia of the extrapulmonary airways of reptiles belonging to the genus Chelonia and Squamata.

Immunocytochemical localization of serotonin in the reptilian lung.

The distribution of serotonin-immunoreactive cells in the lung of 4 species of reptiles was investigated. Serotonin-containing cells were found forming groups in the interconnecting septa in all 4 species studied, and also as solitary cells in Testudo graeca and Mauremys caspica. Serotonin-containing cells were also localized in the intramural ganglia of Pseudemys scripta elegans and Testudo graeca. The present study confirms that serotonin is widely distributed in the lung of vertebrates.