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Biomedical subjects

W Naumann

Publications and source records attributed to W Naumann.

At least 19 recordsLinked to original sources
PubMed1994

Assessing the efficacy of an academic hearing peer tutor for a profoundly deaf student.

This study assessed the efficacy of using a hearing peer tutor to provide math instruction for a profoundly deaf sixth-grade girl. Instruction was provided for twenty minutes each day. A changing criterion design was employed to measure the tutee's progress across four math objectives she had not previously mastered. The peer tutoring intervention was highly successful, with the tutee meeting the criterion of 70 percent accuracy for three consecutive days for each of the four curriculum objectives after only a brief period of intervention. Peer tutoring is discussed as a potentially useful vehicle for mainstreaming deaf children.

Achievement↗
PubMed1993

Tissue culture of bovine subcommissural organ.

Tissue of the secretory, glial subcommissural organ (SCO) of adult, male cattle was cultured in serum-free medium for 70 days in vitro. Only minor alterations in the histoarchitecture and the cytology of the explanted SCOs could be observed by light and electron microscopy. Light- and electron-microscopic immunocytochemical investigations with an antiserum raised against bovine SCO secretory proteins revealed intra- and extra-cellularly localized immunoreactive material in tissue sections of SCO explants cultured up to 69 days in vitro. An indirect competition enzyme-linked immunosorbent assay (ELISA) was developed to detect minor quantities of SCO secretory products. By means of this assay, approximately 35 ng RF protein per ml was detected in culture medium supernatants conditioned for 3 days in SCO tissue cultures at 3, 38, and 69 days in vitro. These studies demonstrate that the bovine SCO can maintain its secretory activity throughout long periods in vitro.

Animals↗
PubMed1991

[Dosage reduction of d-phe-6-GnRH for the regulation of ovulation by complexation with polyglycine].

The gonadotropin-releasing-hormone analogue D-Phe6-GnRH was complexed with polyglycine under non-denaturing conditions. The liberation behaviour of these complexes was investigated in vitro in dependence of hormone content. The "effective dose 50" (ED 50) could be decreased by factor 34 in vivo in mouse ovulation test by reason of protection effect of polyglycine for the hormone against untimely proteolytical degradation.

Animals↗
PubMed1989

[Occupational disability among teachers and its relation to subjective health status and professional performance].

The aim of this study was to examine the relationship between absenteeism and functional health state, action competence, realization of professional goals and essential needs as well as subjective strain in job and family and type A behaviour pattern. The results of discriminant analyses from a sample of 774 teachers (group 1; no sickness leave days, group 2: sickness leave days greater than 28) are discussed.

Absenteeism↗
PubMed1988

[Insulin polyamino acid complexes--a variable principle in the preparation of sustained-release forms].

Polyglycine, polyalanine, polyleucine, poly-alpha-glutamic acid, poly-gamma-glutamic acid and poly-alpha-lysine were complexed with insulin under non denaturating conditions. The liberation behaviour of the hormone was investigated in vivo and in vitro in dependence of the insulin content, mole mass, ionic interaction and hydrophobicity of the polyamino acid. The in vitro results were mainly confirmed by animal experiments and indicated distinct effects of the physiochemical parameters to the bioavailability of insulin. The complex of poly-alpha-lysine and polyglycine were shown to be the most suited retard form, producing significant blood glucose lowering effects up to 12 hours.

Amino Acids↗
PubMed1986

Immuno-electron-microscopic analysis of the basal route of secretion in the subcommissural organ of the rabbit.

Low-temperature-embedded tissue of the subcommissural organ (SCO) of the rabbit was analyzed for the basal route of secretory product by means of indirect immuno-metal cytochemistry (protein A-gold technique) at the electron-microscopic level. By use of (1) an antiserum against bovine Reissner's fibre (see Sterba et al. 1981) and, thereafter, (2) particulate gold-marker solution, immunoreactive sites could be clearly visualized within the extracellular matrix of both (a) the basal part of the ependymal cell layer, and (b) the hypendyma proper. Abundant secretory material was identified within (i) dilated intercellular spaces (a + b) as well as (ii) branching basal lamina labyrinths and distinct perivascular spaces (b). All these compartments are thought to belong to a system of extracellular channels, which may function in secretion directed toward hypendymal blood vessels.

Animals↗
PubMed1986

[A simple method of preparation of keratin filaments and production of a polyclonal broad-spectrum anti-cytokeratin antiserum for immunohistochemical application in fixed and unfixed epithelial tissues].

Rabbits were immunized with 10 nm filaments of a mixture of cytokeratins which has been isolated from human heel callus material and reconstituted to filaments in vitro. The antisera to keratins (ASK) have been tested histologically at fixed and unfixed tissue samples by means of the indirect immunofluorescence and PAP technique. The ASK recognized specifically only the epithelial cells of skin, of the mucous membranes of mouth and digestive tract, of salivary glands, sweat gland and mammary gland, but did not react with hepatocytes or kidney cells. The following tumors, tested till now, reacted with the antikeratin antisera: epithelial and lymphoepithelial carcinomas of skin, mouth and digestive tract, carcinomas of salivary glands, mammary gland and thyroid gland, adamantinoma, basalioma of skin, and metastases from carcinomas.

Animals↗
PubMed1986

[Immunohistochemical investigations on the ontogenesis of the subcommissural organ].

Using an antiserum raised against bovine Reissner's fiber a ventricle border of the matrix epithel reacting in the immunohistochemical procedure according to Sternberger et al. (1970) is visible in the very early stage of the embryonic brain of Pleurodeles waltli. In the basal region of the brain the immunoreactive border later develops into the flexural organ a secretory cell formation that is situated in the deuterencephalon and spinal cord. The cells of the flexural organ release a glycoprotein into the cerebrospinal fluid, where, among other things, the Reissner's fiber is formed. Later on, Reissner's fiber is produced no longer by the flexural organ, but the subcommissural organ. It is suggested that in the very early embryonic stage the immunohistochemically reactive ventricle border, too, contains a glycoprotein that might contribute to any events in the ontogeny of the nervous system.

Animals↗
PubMed1984

Preparation and discharge of secretion in the subcommissural organ of the rat. An electron-microscopic immunocytochemical study.

The secretion of the subcommissural organ (SCO) of the rat was studied by means of immunocytochemistry at the electron-microscopic level with the use of (1) the polar embedding medium Lowicryl K4M at -30 degrees C, (2) the protein A-gold technique, and (3) a rabbit antiserum against bovine Reissner's fiber (see Sterba et al. 1981). Two different substructures of the ependymal and the hypendymal SCO-cells display a positive immunocytochemical reaction: (1) sacs containing flocculent secretion, which originate from the granular endoplasmic reticulum, and (2) vacuoles filled with fine granular secretion, which are pinched off from the Golgi apparatus. The secretory material of the sacs and the vacuoles is discharged both (i) apically into the cerebrospinal fluid and (ii) basally into intercellular spaces of the SCO-hypendyma. The apically released secretion is condensed to a lamina-like formation, which more caudally assumes the form of Reissner's fiber. The route of the basally released secretion remains, however, vague. The "periodically striated bodies", which were thought to be morphological mediators of the discharge of the secretion into the capillaries, are never labeled by gold particles.

Animals↗
PubMed1982

[Immunocytochemical demonstration of neuropeptides (neurophysin and oxytocin) by the protein A-gold technic].

In the classic peptidergic neurosecretory system of vertebrates the neurohormone oxytocin is associated with the carrier protein neurophysin. By using small gold particles (3 to 12 nm) in the protein A-gold technique, both the hormone and the carrier-protein will be labelled, while larger particles (20 nm) label only the neurophysin. To bind the latter particles, a greater number of Fc-regions of antigen-IgG-complexes seems to be necessary.

Animals↗
PubMed1981

Immunocytochemical investigation of the subcommissural organ in the rat.

The results of a preliminary immunocytochemical investigation on the subcommissural organ (SCO) in rats show that (1) Reissner's fiber (RF) or essential compounds of the RF are produced by the SCO, (2) the immunoreactive material is produced in the epithelial cells of the SCO as well as in the hypendymal cells, and (3) the immunoreactive material of the SCO belongs to a category of endogenous peptides to date not demonstrable immunocytochemically in other brain structures.

Animals↗
PubMed1979

Peptide containing vesicles within neuro-neuronal synapses.

In the descending part of the classical neurosecretory system, the axon terminals are not differentiated or they take the form of presynaptic elements which then form synaptoids or synapses with pituicytes or adenohypophyseal glandular cells respectively. In contrast, the axon terminals of the ascending part fulfil the criteria of true presynaptic elements which form synapses with other neurones. The presence of neurophysin vesicles in the presynaptic element is a particular morphologic feature of these neuro-neuronal synapses.

Animals↗