PubMed Health⌕ Search

Biomedical subjects

K Schippel

Publications and source records attributed to K Schippel.

At least 19 recordsLinked to original sources
PubMed2005

Identification of potent odorants in different cultivars of snake fruit [Salacca zalacca (Gaert.) Voss] using gas chromatography-olfactometry.

Three cultivars of snake fruits, Pondoh Hitam, Pondoh Super, and Gading, were freshly extracted using liquid-liquid extraction. The aroma compounds of the three samples were analyzed by GC-MS and GC-olfactometry using the nasal impact frequency (NIF) method. A total of 24 odor-active compounds were associated with the aroma of snake fruit. Methyl 3-methylpentanoate was regarded as the character impact odorant of typical snake fruit aroma. 2-Methylbutanoic acid, 3-methylpentanoic acid, and an unknown odorant with very high intensity were found to be responsible for the snake fruit's sweaty odor. Other odorants including methyl 3-methyl-2-butenoate (overripe fruity, ethereal), methyl 3-methyl-2-pentenoate (ethereal, strong green, woody), and 2,5-dimethyl-4-hydroxy-3[2]-furanone (caramel, sweet, cotton candy-like) contribute to the overall aroma of snake fruit. Methyl dihydrojasmonate and isoeugenol, which also have odor impact, were identified for the first time as snake fruit volatiles. The main differences between the aroma of Pondoh and Gading cultivars could be attributed to the olfactory attributes (metallic, chemical, rubbery, strong green, and woody), which were perceived by most of the panelists in the Pondoh samples but were not detected in the Gading samples. This work is a prerequisite for effective selection of salak genotypes with optimal aroma profiles for high consumer acceptance.

Arecaceae↗
PubMed1990

[Vascular endothelium (review). I. General morphology. 2A: histogenesis of the vascular endothelium].

Determination, differentiation, and specialization of vascular endothelium are the main steps of its histogenesis. The source of the first determined endothelioblasts are condensed mesenchymal cells (blood islands) at the yolk sac (extraembryonal) and also in the intraembryonal mesenchyme. The term of determination is not yet known. The marginal cells of the blood islands differentiate into primordial endothelial cells forming primitive vessels by migration, proliferation, fusion, and selection. This "vasculogenesis" is induced by specific matrix components produced by the endothelioblasts themselves and other not known factors. Formation of secondary capillary plexuses is related to organogenesis and takes place by sprouting from preexisting endothelium ("angiogenesis"). Factors which induce and promote angiogenesis were isolated from different embryonic organs. Migration, proliferation, and tube formation are regulated by extracellular matrix components (fibronectin, laminin). Main features of primordial endothelium of protocapillaries are: irregular profile, abundance of synthetic organelles, lack of plasmalemmal vesicles and basement membrane, production of specific matrix components. Specialized endothelium (continuous, fenestrated, discontinuous a.s.o.) develops from secondary plexuses influenced by factors of the specific organ tissue. The probably mechanism by which the endotheliocytes reach their final shape and behavior is discussed; some morphological and functional properties during maturation are documented. The maturation of endothelium is related to establishing of the specific blood-tissue barrier.

Animals↗
PubMed1990

Abnormal drainage of the middle cardiac vein (V. cordis media).

The middle cardiac vein (V. cordis media) which is known to be one of the tributaries of the coronary sinus (Sinus coronarius) is found to open into the left atrium in a 79 years old female cadaver. The ostium is guarded by a semilunar (crescent shaped) valve.

Aged↗
PubMed1989

[Vascular endothelium--a review. I. General morphology of the vascular endothelium].

The vascular endothelium as a monolayer interposed between blood/lymph and interstitial fluid realizes different functions as continuous circulation of blood/lymph, processes of clotting, fibrinolysis and antithrombotic surface properties, some aspects of defense, inflammation, different synthetic activities, and establishing of exchange pathways and barriers for several substances. This survey will be presented as a sequence of 6 single articles. The 1st one deals with the general morphology of vascular endothelium. Heteromorphism of endothelium means variability of shape and orientation as a result of different functional conditions, mediated by the cytoskeleton. "Contactons" are units of interconnected cells; each cell exhibits 4 zones of different structural and functional specialization: nuclear-, organelle-, peripheric-, and contact zone. Membrane associated structures of the surface are the glycocalix and the subplasmalemmal subcortical layer. Composition and function of these including the plasmalemma itself are explained. Structures formed by the endothelial plasmalemma are vesicles, fenestrations, pores, gaps, and microvilli. Arrangement, function, dynamics, and their relationships to the cytoskeleton are referred including TEM, SEM, and Freeze Etching techniques. Concerning interendothelial contacts, different types of junctions and 4 types of junctional fibrils are described. A short structural description of the basement membrane and of the organelles of endothelium is given. Some new informations of the endothelial cytoskeleton, concerning composition, structure, arrangement, properties, and relationships to other subcellular constituents are presented, completed by impressive SEM-photographs.

Animals↗
PubMed1988

Ultrastructure of rabbit retinal nerve fibre layer--neuro-glial relationships, myelination, and nerve fibre spectrum.

The ultrastructure of the rabbit retinal nerve fibre layer was studied both in retinal centre and periphery. The central nerve fibre layer was found to contain large masses of--mostly myelinated--nerve fibres, somata and processes of astrocytes and oligodendrocytes, vitreal processes of Müller cells, and blood vessels. Astrocyte and Müller cell processes could be discriminated both by their direction and by the thickness of their intermediate filaments which was about 7 nm in Müller cells and about 10 nm in astrocytes. Some peculiarities of nuclei and cytoplasmic organelles of rabbit retinal astrocytes and oligodendrocytes are described. Myelin sheaths are demonstrated to be derived from oligodendrocytes; in some cases, two axons were found within a common myelin sheath. In the retinal periphery, only sparse thin bundles of unmyelinated axons were found in between a thick row of big Müller cell endfeet; astrocytes, oligodendrocytes, and blood vessels were missing here. In both retinal regions, node-like membrane specializations of optic axons were found; these were always surrounded by a corona of fine glial processes arising from astrocytes as well as from Müller cells. The features of myelination within the rabbit nerve fibre layer were quantified, and compared with recent literature data. A hypothesis is offered relating the production of myelin to the release of diffusable substance(s) by active axons. This hypotheses allows to account for the striking finding that relatively thick axons remain unmyelinated in the nerve fibre layer of most mammalian retinae like in the rabbit retinal periphery whereas they become myelinated in the central rabbit retina like in central nervous system in general.

Animals↗
PubMed1983

[Electron microscope studies of the structure and junctions of heart and skeletal muscle capillaries in the rat during pre- and postnatal development].

Comparative investigations with freeze etching procedure of capillaries of the rat heart and triceps muscle (fetal and some postnatal stages) reveal some differences of the junctional structures. Junctions of the skeletal muscle capillaries show several parallel arranged rows of partly linked and interrupted junctional strands with relative few junctional particles. In the 3rd week of life, we found also short fragments of non parallelized strands densely covered with particles which could be related to the venous segment of the capillary. The junctions of myocardial capillaries show a reduced number of mostly zigzag-like arranged junctional strands with many particles and large non sealed gaps. Areas with extremely reduced strands were kept for the venous segments. The above described differences could be responsible for the better permeability of the heart capillaries to horse radish peroxidase.

Animals↗
PubMed1982

[Modern electron microscopy methods in the study of ultrastructure and function of the terminal vascular system].

The present survey deals with the possibilities of electron microscopic methods, with the gain of information by its use and with its prospective significance in solving actual problems in the subject of microcirculation. The paper consists of the subsequent parts: 1. Fixation methods; 2. Topical methods for ultrastructural investigation of defined areas of the terminal vascular bed and the transmural ways of transport of molecules; 3. Freeze etching technics; 4. Electron microscopic autoradiography; 5. Transmission electron microscopy including methods for three-dimensional reconstruction of vascular segments; 6. Scanning electron microscopy; 7. X-ray microanalysis; 8. Demonstration of cell receptors with the aid of lectines; 9. Methods for quantitative analysis. In each chapter the possibilities and disadvantages of the methods and the most frequently occurring artefacts were dealt. The survey concludes with a consideration of the prospective development of electron microscopic technics and its use in the investigation of the terminal vascular bed. In the opinion of the authors the methodical development will take the subsequent direction: 1. Further completion of the preparative methods and its development to routine technics combined with the more general use of necessary tools; 2. Further completion and spreading of quantitative investigation methods; 3. More effective use of the synthetic analysis solving a problem, that means, the simultaneous application of different methods (for instance: transmission electron microscopy, scanning electron microscopy, experimental methods and so on).

Animals↗
PubMed1981

[Demonstration of ATPase activity in skeletal muscle fibers of the triceps muscle of arm in white rats during development].

On the base of modified calcium and method from Zebe and Falk (1964) for demonstration of ATPase activity results at the long head of the triceps muscle of white rats aged 1, 3, 6 weeks and 3 month were shown. This method is proper to make visible alteration of the localisation of the reaction product during the postnatal development. Further investigations are necessary in order to correlate the steps of differentiation of muscle fibres with the strength of ATPase activity.

Adenosine Triphosphatases↗
PubMed1981

[Permeability characteristics of the endocardium and the myocardial capillaries to horseradish peroxidase in fetal and postnatal rats].

After intravenous or intracardial application of horseradish peroxidase (HRP) at the myocardial capillaries of fetal, juvenile and adult rats a fast transport of the tracer into the interstite can be observed. In the fetal cases the transport takes place especially through the interendothelial junctions, in the postnatal cases a considerably amount of the peroxidase traversed also by plasmalemmal vesicles. In adults the T-tubules of the myocytes are labelled already after 15 min of circulation. From fetal stages up to adults the junctions of the endocardium are well permeable to HRP. After a short circulation time we found large deposits of reaction product in the subendocardial space. The reasons for the different permeability of fetal heart and skeletal muscle capillaries were discussed.

Aging↗
PubMed1980

[Electron microscopic study of the permeability of terminal blood vessels of the M. triceps brachii to horseradish peroxidase in fetal, juvenile and adult rats].

At the basis of some ultrastructural differences in fetal, juvenile and adult rat triceps muscle capillaries as described in preliminary papers the permeability of these capillaries to horse radish peroxidase was investigated. Capillaries of fetal and juvenile rats up to the 3rd week after birth were impermeable to horse radish peroxidase (HRP) for 2 and 10 minutes after injection, which can be explained with the low pinocytotic activity and the more complex structure of the junctions. Capillaries of the triceps brachii muscle in adult rats aged 2 month and more show a low permeability to HRP 2 and 5 minutes and a high permeability 15 minutes after the injection of the tracer. In the capillary segment of the terminal bed the tracer was traversed especially by the means of vesicles and some transendothelial channels built by linked vesicles. The interendothelial junctions seemed to be tight. In the venular segment of th capillaries and in small postcapillary venules additional to the vesicular transport a high permeability of some junctions was stated. The significance of the different permeability of distinct segments of the terminal vascular bed to small macromolecules is discussed with respect to the theories of th physiologists and compared with the results of recent investigators.

Animals↗
PubMed1979

[The Sézary syndrome--an erythrodermic T-cell-lymphoma].

Report on a 75-year-old patient with Sézary syndrome which is characterized by the following leading symptoms: Erythrodermia, leukocytosis, circulating atypical lymphocytes with cerebriformous nuclei (Sézary cells) and swollen lymph nodes. Light microscopic and electron microscopic findings refer to a transitory situation of the Sézary cells from the reactive character to the (pre)neoplastic one. The disease is classified by T-(helper)cells as a low grade non-Hodgkin-lymphoma in parallel to mycosis fungoides and in general it finishes lethally after a course of 5 to 8 years. Apart from local steroid ointments and UV-irradiations the internal application of steroids, in the late stage if necessary in combination with cytostatics is recommended for therapy.

Aged↗
PubMed1978

[Light and electron microscopic studies of the skeletal muscle (M. triceps brachii) capillaries in white rats aged 2 to 20 months].

The capillarisation of the triceps muscle of white rats was investigated with light and electron microscope up to the age of 20th month. During the postnatal development the capillary to fiber ratio corresponding to the increase of the number of capillaries is well adapted to an exponential function. The rapid increase of thickness of the muscle fibers causes a decrease of the number of capillaries per area unit. After the third week of life with histochemical methods the differentiation of muscle fiber types is possible, well correlated to the beginning of motoric activity. Ultrastructural alterations of the muscle capillaries consist in a flattening of the endothelium within the first month of postnatal life, a decrease of the content of organelles, a high degree of vesiculation and a continuous thickining of the basement membrane up to more than 100 nm. The interendothelial clefts show a simple structure containing 1--2 junctional zones and only few dilatations.

Aging↗