Jochen Schindelmeiser

The blood-testis barrier in vertebrates having different testicular organization

SummaryThe occurrence of tight junctions between Sertoli cells, providing the structural basis of the blood-testis barrier, has been studied using hypertonic fixative and lanthanum tracer in the testes of seven species of vertebrates having different testicular organization. In all cases inter-Sertoli tight junctions, establishing an effective barrier, appear either when meiosis is complete (teleosts and amphibians, both with cystic testes) or immediately after the onset of meiosis (reptiles and birds, both having testes consisting of seminiferous tubules). In the cystic testes, tight junctions are regularly associated with desmosomes, whereas in testes with seminiferous tubules, cisternae of the endoplasmic reticulum are present beneath the junctions (subsurface cisternae). The avian testes examined have, in addition, septate-like junctions between the Sertoli cells but before the tight junctions.

Observations on the blood-testis barrier in a frog and a salamander.

SummaryA blood-testis barrier has been demonstrated in a frog, Rana esculenta, and in a salamander, Salamandra salamandra, using lanthanum as an electron-dense marker during fixation. The tracer penetrates the interstices between somatic follicle or Sertoli cells and germ cells in regions of the testis containing spermatogonia and spermatocytes, up to the level of punctate tight junctions. The latter can be localized between the somatic cells that line seminiferous units containing spermatids and mature spermatozoa. The barrier thus appears to be established after meiosis in both species investigated, although spermatids of different developmental stages can be found in open compartments of the testis in S. salamandra.

Photoperiodic influence on the innervation of the ductus epididymidis and ductus deferens of the Djungarian hamster, Phodopus sungorus: electron-microscopic and biochemical results

SummaryThe influence of long (light: dark 16∶8) and short (light:dark 8∶16) photoperiods on the autonomic innervation of the ductus epididymidis and the ductus deferens of Phodopus sungorus was studied using electron microscopy with morphometric analyses, and biochemical methods. At short photoperiods, only the large smooth muscle cells in the ductus deferens became atrophic, the number of mainly adrenergic varicosities in the smooth muscle layer decreased, and the mean distance between varicosity and smooth muscle cells increased. The content of noradrenaline was determined by high-performance liquid chromatography with electrochemical detection. For the ductus deferens, the noradrenaline content was reduced at LD 8∶16 to less than 10% of the initial value. Short photoperiods are proposed to influence only the adrenergic innervation of the large smooth muscle cells of the ductus deferens. These cells are believed to exert a trophic influence on their nerves.

Nitrogen excretion in intra- and extrauterine larvae of the ovoviviparous salamander, Salamandra salamandra (L.) (amphibia, urodela)

Abstract 1. 1. Uterine fluid of pregnant females of the ovoviviparous Salamandra salamandra contains rather high amounts of urea (576mmol/l) as compared to non pregnant females (150 mmol/l). 2. 2. The same applies to the urea content of the plasma (pregnant female 19.4 mmol/l; non pregnant female 7.8 mmol/l). 3. 3. These data indicate ureotelism in intrauterine larvae. 4. 4. During extrauterine larval life ammonia excretion was found to be slightly higher than urea excretion. 5. 5. During metamorphosis ureotelism again becomes predominant. 6. 6. The capacity for urea synthesis in intrauterine larvae can be regarded as an adaptation to the prolonged stay in utero, where availability of fluid is greatly limited.

Immunohistochemical characterization of purple acid phosphatase-containing leucocytes in the human placenta

SummaryA tartrate-resistant acid phosphatase activity was detected in the human placenta. This enzyme displayed immunological properties similar to those of the group of purple acid phosphatases that can be demonstrated with a rabbit polyclonal antibody against bovine spleen purple acid phosphatase. The placental enzyme was mainly localized immunohistochemically to neutrophil granulocytes of the maternal blood between the placental villi and within foetal capillaries using the bovine spleen antibody and the commercial monoclonal antibody M1 directed against an antigen found on mature granulocytes. A minor activity was detected in decidual cells and the syncytiotrophoblast. The presence of purple acid phosphatase in placental granulocytes may be related to special immunological conditions of pregnancy.

Morphological and biochemical studies on the innervation of the testis of Salamandra salamandra (L.) (Amphibia, Urodela)

The innervation of the male gonad of Salamandra salamandra was studied by fluorescence microscopy using the glyoxylic acid method, acetylcholinesterase histochemistry, electron microscopy using glutaraldehyde/osmium tetroxide and chromate/dichromate fixation, and high-performance liquid chromatography (HPLC) with electrochemical detection of biogenic amines in homogenates of the testicular tissue. Noradrenaline has been found to be the prevailing neurotransmitter in the testicular nerves; dopamine could be identified only in minor concentration. The relatively scarce noradrenergic innervation is mainly restricted to the connective tissue septa between the immature and the mature part of the testis and between the mature part and the glandular tissue. Most of the fluorescent fibers have a close connection to blood vessels. After chromate/dichromate fixation the nerve profiles contain in most cases small vesicles with electron-dense reaction products, indicating the presence of catecholamines. Varicosities are to be found near the capillaries, in the vicinity of vascular (in the wall of arterioles) and non-vascular (near the testicular surface) smooth muscle cells; no relationships were found between nerve fibers and glandular (steroid hormone-secreting) or germinal cells. Cholinergic fibers could not be identified, non-adrenergic/non-cholinergic fibers were present only in very small numbers.

The innervation of the uterus in Salamandra salamandra (L.) (Amphibia, Urodela)

SummaryThe innervation of the uterus in the ovoviviparous urodele Salamandra salamandra was studied. In whole mount preparations of the thin-walled uterus of pregnant females, a dense adrenergic network was demonstrated using a modified glyoxylic acid fluorescence technique. Based on vesicle type and cytochemical reactivity after chromate/dichromate fixation for electron microscopy at least two types of neural process were distinguished and classified as adrenergic and cholinergic. Both types are preferentially situated above or between the smooth muscles of the uterine tissue. Adjacent to the muscles in the walls of arterioles mainly adrenergic fibers are seen. Using high performance liquid chromatography with electrochemical detection in tissue homogenates of uterus a considerable amount of noradrenaline could be identified. The significance of the dense innervation is discussed with respect to the function of the uterus during pregnancy and birth.

Hepatic arginase activity in intra- and extrauterine larvae of the ovoviviparous salamander. Salamandra salamandra (L.) (Amphibia, Urodela).

The hepatic arginase activity of Salamandra salamandra was determined at three different stages of intra- and extrauterine larval development and at fully metamorphosed juveniles. The highest enzymatic activity was found in intrauterine larvae in November, the lowest in intrauterine larvae in June of the following year. These data can be correlated with the ureotelism of intrauterine larvae previously described and are discussed with respect to the metabolism of larval and juvenile fire salamanders.

Light and electron microscopic study on complex carbohydrates in the testis of Salamandra salamandra L. (Amphibia, Urodela)

The distribution of complex carbohydrates was studied in the testis of the European fire salamander, Salamandra salamandra, by light- and electron-microscopic methods. The basal laminae and fibrous structures in the connective tissue between the lobules are PAS-positive. After alcianblue staining (at pH = 2.8), acid mucopolysaccharides could be demonstrated in steroid hormone-producing cells in the interstitial tissue between lobules containing spermatids, spermatozoa, and lobules after spermiation, as well as in most of the Sertoli cells in lobules after spermiation. In all spermatogenic stages from secondary spermatocytes to mature sperms, dictyosome-like structures and flat vesicles showed a distinct contrast enhancement, as did parts of the acrosome after treatment with the phosphotungstic acid-chromic acid method for electron microscopy.