Secretory polymorphism and serous cutaneous gland heterogeneity in Bufo granulosus (Amphibia, Anura).

Three types of secretory products (a, b and c) in the poison glands of the Argentine toad Bufo granulosus have been detected under light microscope. The type a secretory product consists of granules of homogeneous density, type b of vesicles with a translucent compartment and type c of granules of varying density. Subsequent transmission electron microscope analysis disclosed obvious similarities in the secretory pathways of type a and c granules; the differences detected under light microscope are due to the functional phases observed. On the contrary, production of type b secretory vesicles involves a distinctive pathway. Therefore, two classes of glands (I and II) have been identified. Glands of the first class are typical of bufonid toads and produce granules provided with repeating substructure; glands of the second class, which manufacture a lucent product, are unusual in the family Bufonidae. Ultrastructural differences, consistent with the two gland classes, have also been described in the myoepithelia. The myocytes ensheathing class I secretory units possess striking cytoskeletal specializations, whereas those of class II glands are rich in sarcoplasmic reticulum. The distinctive ultrastructural traits detected in these myoepithelial cells have been compared with the results of previous studies on the dimorphic serous glands of Bombina. Findings point to the use of pharmacological treatment on the skin of anurans with different classes of serous glands to elicit differential secretory discharge.

Granular cutaneous glands in the frog Physalaemus biligonigerus (Anura, Leptodactylidae): comparison between ordinary serous and 'inguinal' glands.

Beside the ordinary granular (or serous) glands, the skin of the leptodactylid frog Physalaemus biligonigerus possesses peculiar clusters of large granular units, the 'inguinal' glands, located in the dorsolateral areas of the pelvic girdle. Both gland types store their specific products within the syncytial cytoplasm of the secretory unit. These secretory materials consist of spheroidal or ellipsoidal bodies (granules) with a repeating substructure. The subcellular features of the immature products of the ordinary serous and inguinal glands are identical. However, these products undergo divergent maturative processes, leading to fluidation on the one hand and condensation on the other. Secretory release into the small gland lumen was observed in both cases, involving merocrine mechanisms. On the basis of the analysis of cutaneous serous gland polymorphism in anurans, the inguinal units in P. biligonigerus do not appear to be an independent line. Rather, these large units belong to the ordinary serous type and represent a gland population specialized in the storage of remarkable amounts of product used in chemical defence of the skin.

Comparative biology of sperm storage in female salamanders.

Females in seven of the ten families of salamanders possess cloacal glands called spermathecae that store sperm. The annual cycle of sperm storage has been studied by light and electron microscopy in eight species representing five families. In these taxa, we recognized 14 characters associated with the spermathecae and traced their evolution on a phylogeny of salamanders based upon other characters. The plasticity and phyletic significance of the spermathecal characters varied greatly. Plethodontids have complex spermathecae while other families possess simple spermathecae; thus, this character has phyletic value as well as being highly conserved within the Salamandroidea. Other characters, such as carbohydrate histochemistry, are highly plastic and show no obvious phyletic trends. The significance of some of these variable characters, such as duration of sperm storage, is apparent only after including in the analysis other aspects of the reproductive cycle, such as length of the mating season. Additional comparative studies, employing the protocol used in this paper, will help further clarify the relationships between phyletic and functional variability in sperm storage mechanisms in salamanders.

Serous gland dimorphism in the skin of Melanophryniscus stelzneri (Anura: Bufonidae).

Two serous gland types (I and II) in the skin of the Argentine toad Melanophryniscus stelzneri were discovered using light and electron microscopy. Glands of the two types differ in several traits: features of the products (both mature and immature), organelles involved in biosynthesis, and paths of serous maturation. No consistent differences, however, were detected between the myoepithelial sheaths encircling the secretory units. Type I glands manufacture vesicles containing a single dense body with a repeating substructure and conform to the fundamental secretory line of bufonid skin, a secretory line involved in biosynthesis of steroids. Type II glands synthesize granules of varying densities and seem to belong to a line of glands that secrete proteinaceous products. The occurrence of the two serous gland types in Melanophryniscus stelzneri is discussed in a comparison with current literature on the morphofunctional characteristics of anuran poison glands, which perform both regulative and defensive roles. It is suggested that di- or polymorphism in serous glands is an adaptive trait that allows differential release of active molecules on the body surface.

Serous cutaneous glands in Phyllomedusa hypochondrialis (Anura, Hylidae): secretory patterns during ontogenesis.

Three syncytial gland types (Ia, Ib, and II ) have been described in the skin of larval, juvenile and adult Phyllomedusa hypochondrialis, which share the ultrastructural traits common to the serous secretory units of anuran skin, although each manufactures a peculiar product. Type la secretion consists of dense granules provided with a peculiar substructure, type Ib of vesicles holding a lucent material, type II of lipid deposits. None of the developmental stages investigated showed intermediate features between any of the three cutaneous products, which accumulate in the syncytial cytoplasms of the secretory units following different biosynthetic pathways, consistent with each gland type. These findings confirm previous results on adult specimens of P. hypochondrialis and P. sauvagei and stress the polymorphism of the serous glands in the genus Phyllomedusa. This morphological variability reflects the wide adaptive flexibility of serous glands in anurans.

Sperm morphology of salamandrids (Amphibia, Urodela): implications for phylogeny and fertilization biology.

Mature spermatozoa belonging to four salamander species, Salamandrina terdigitata, Triturus alpestris, Triturus carnifex and Triturus vulgaris, have been investigated by electron microscopy. The sperm ultrastructure of these species was compared with that of previously examined urodeles (36 species and 20 genera) and with that of anurans and caecilians. Many phylogenetic considerations may be inferred as a consequence of comparative spermatology. Urodela appears to be a monophyletic order characterized by three sperm synapomorphies: the acrosomal barb, nuclear ridge and marginal filament. Cryptobranchoidea are confirmed to form a monophyletic suborder having two synapomorphic characters: absence of mitochondria in the tail, and cylindrical shape of the tail axial rod. Within the family Salamandridae, sperm morphology confirms the phylogenetic distance between Salamandrina and Triturus, as already pointed out on the basis of molecular and morphological characters. The very complex ultrastructure of spermatozoa confirms a previous opinion that internal fertilization is the ancestral condition of the Amphibia.

Serous cutaneous glands of the western spade-foot toad Pelobates cultripes (Amphibia, Anura): an ultrastructural study on adults and juveniles.

The venom glands of the western spade-foot toad Pelobates cultripes were studied under light and electron microscopes. The glands exhibit the structural patterns usual in anurans, including the typical secretory syncytium. The peripheral cytoplasm contains a single row of nuclei and secretory organelles related to proteosynthesis. The inner cytoplasm is filled with large vesicles holding a thin product which originates from the merging of smaller ones containing a thicker material derived from the Golgi apparatus. The appearance and maturation of P. cultripes venom have been compared with patterns of biosynthesis and secretory evolution described in serous cutaneous glands of several anuran species. Following these criteria, the traditional trends in the terminology and classification of serous glands in anuran skin are discussed and reviewed.

Cytochemical study of larval skin in Amphibia: occurrence of ruthenium red positive cells in cutaneous gland anlagen.

During a cytochemical investigation into the development of cutaneous gland buds in amphibian larvae (both anuran and urodele), ruthenium red (RR) positive cells were found in the anlagen. These cells, with diffuse deposits of the polycation dye in their cytoplasms, were first detected on the lateral surface of still intraepidermal gland buds. Later, during segregation of anlagen from the epidermis, the reactive cells were followed whilst they converged towards the apex of the gland nest. These findings of a remarkable penetration of RR through intact plasma membranes are discussed in the light of the staining characteristics of the polycation dye. Furthermore, the mechanism regulating morphogenesis of amphibian cutaneous glands is briefly compared with the morphogenetic patterns of large exocrine glands in higher vertebrates. It is suggested that during fixation RR penetrates morphogenetically active cells, following the same pathways as calcium under physiological conditions. Calcium inflow correlates with the occurrence of thin, possibly contractile, filaments in these cells and also agrees with cell migration during morphogenesis.

The squash-smear technique in the diagnosis of spinal cord neurinomas. Report of three cases.

The squash-smear technique was used instead of frozen sections for the rapid intraoperative diagnosis of three neurinomas of the thoracic spinal cord. Characteristic cytologic features that could be considered of diagnostic value were the absence of recognizable cytoplasmic outlines, the elongated, sometimes-wavy appearance of the nuclei and the dense fibrillary background. Nuclear palisades with formation of Verocay bodies were present in one case; these were also identified in the paraffin-embedded permanent sections. Histologically, the tumors were predominantly Antoni type A neurinomas.

Cytology of giant-cell glioblastoma.

A case is presented in which smears and touch imprints of a parietal tumor in a 58-year-old female revealed two distinct and easily recognizable cellular populations. The first was predominant and consisted of densely packed cells of an astroglial nature. The other was made up of unusually large giant cells with highly malignant features. The cytology of these combined cell types allowed the correct diagnosis of giant-cell glioblastoma at the time of surgery. Their cytomorphology, which has seldom been reported, supported the interpretation of an astroglial nature of this tumor.

Development of cutaneous glands in Salamandrina terdigitata (Lacépède, 1788) (Amphibia: Urodela); findings by light and electron microscopy.

Cutaneous glandular Anlagen in Salamandrina terdigitata appear in the early larval stages as sphere-shaped intraepidermal cell nests. A stromal screen rises into the epidermis from the primordial dermis surrounding the Anlagen and isolates them from future keratinous elements. At this stage the only contact between the stroma and the gland blastocytes is through their cell coat, whilst the adjacent keratinocytes show a complex dermo-epidermal type junction. This structural asymmetry, confirmed by cytochemical findings, plays a direct role in guiding processes governing glandular bud differentiation. Interactions are in fact established between the stroma and the ample portion of the Anlage which it surrounds, which coordinate development, initiating differentiation of the contractile and secretory elements. Only a few bud cells, grouped below the epidermal basal layer, avoid such contact with the dermis, and constitute the regenerative matrix of the gland by maintaining their indifferentiated state. Above these, several keratinocytes form the excretory duct.

Symptomatic subependymoma of the fourth ventricle. Case report.

Symptomatic subependymomas of the fourth ventricle are rare and usually not included in the preoperative differential diagnosis of tumors in this region. The case of a 63-year-old man with fourth ventricle subependymoma is described. For several years he had suffered with nausea and vomiting, and now presented signs of direct involvement of the posterior fossa. He was investigated preoperatively with computerized tomography, but the ultimate diagnosis was not suspected at that time. The tumor was diagnosed as an subependymoma at operation and was totally excised. This tumor type can easily be recognized on intraoperative frozen section, and its diagnosis should always lead to an attempt at complete surgical removal.

On the pathology of meningiomas. A study of 412 cases.

Some pathological features of tumors arising primarily in the meninges are discussed on the basis of 412 surgically treated meningiomas during the period running from 1964 to 1978. Cases of meningeal sarcomas were not considered. Except for a few cases, pathology and clinical course have been generally in agreement. The incidence of histological types like meningotheliomatous, fibroblastic, angioblastic or atypical meningiomas has been verified in relation to sex, age and intracranial or spinal conventional locations. The problem of recurrencies has been studied either comparing the histological features with the first observation or comparing histopathological types with location and details of surgical procedure. Additional criteria like uni or multifocal origin of the tumors and histological features of the peri-lesional tissues, often harbouring small meningiomatous nests, have been taken into account.

Meningiomas. A light and electron microscopy study.

A morphological and ultrastructural study was undertaken from a personal series of meningiomas. Especially the fine structure of the tumour has been described by the electron microscopic study of 16 meningotheliomatous and 4 fibroblastic meningiomas. In all cases, it was possible to distinguish certain cells with epithelial features such as desmosomes, microfilaments and interdigitating extensions. Also the cytological patterns of fibroblastic meningiomas usually were similar to the meningotheliomatous type, anyhow the intercellular space between the interdigitating extensions of adjacent cells was occupied by collagen-fibers. At present, it has been impossible to demonstrate the capability of the tumour cells to synthetize collagen. Since the tumour cells of both the meningiomas are substantially similar to the subarachnoid space meningocyte, it is concluded that the neoplasm rises from a cell with double potentiality for fibroblastic and epithelial differentiation.