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Biomedical subjects

H Fischer

Publications and source records attributed to H Fischer.

At least 577 records · Page 32Linked to original sources
PubMed1975

[Light and electron microscopic studies of slowly adapting abdominal stretch receptors of the American river crayfish Orconectes limosus (RAF)].

The slowly adapting abdominal stretch receptors of Orconectes limosus (RAF) have been investigated morphologically; 1. Despite their variety of size and shape all slowly adapting receptor neurons show common characteristic features which in addition distinguish them clearly from the fast adapting receptor neuron type SN2. The slightly globular cells have always several dendrites (often 4-6). They originate apical or lateral to the neuron, are oriented mainly longitudinal to the muscle fibres and are brodly ramified. The fine dendrites form a 3-dimensional fibrilar network. 2. The structure and distribution of the connective tissue in the "intertendon" of the muscle receptor organ correspond to the dendrite ramification; In this area, some muscle fibres end direktly at tendon-like connective tissue structures, but a number of different fibres run uninerruptedly through the whole muscular fascicle. 3. The perikaryon of every sensory neuron shows 2 "cytoplasm types" which are clearly distinguishable one against the other. A characteristic feature of the granular-lamellar neuroplasm that closely surrounds the nucleus are many flat vesicles of the granular endoplasmatic reticulum, accumulations of free ribosomes, numerous mitochondria and Golgi fields. The fibril-rich neuroplasm on the contrary contains only few mitochondria, but very many neurofilaments, here and there also neurotubuli. It projects directly into the dendrites and neuritek. Cell bodies, axon and dendrites are surrounded alternatingly by sheath cells and connective tissue of collagenous nature. The innermost layer of the coat cells borders directly on the neuron membrane. Finer dendrites are enclosed by nothing more but a thin layer of sheath cell plasm and intercellular substance. The dendrite terminals are either stored directly in connective tissue ground substance or border immediately on the sarcoplasm. 5. The axo-dendritic or axo-somatic synapses, respectively, contain numerous ellipsoidal (250-350 X 400-500 A), but also many spherical, vesicles. Some vesicles have a slightly larger diameter (700-900 A) and contain an electron-dense core. The synaptic gap measures 150 to 200 A. The neuromuscular (supposedly excitatory) synapses are filled much lighter with vesicles as compared with those just mentioned, which show a relatively unique form and size (nearly all spherical, phi 400-500 A). There are less vesicles with an electron-dense centre. On the average, the synaptic gap is broader (200-250 A) and the contact zone is larger. Apart from these, terminals could be observed in the dendritic ramification area, too, resembling the axo-dendritic and axo-somatic ones, respectively. 6. Finer dendrite branches contain vesicles differing slightly from those mentioned above as far as shape and size are concerned. Their diameters vary between 500 and 1 000 A. "Dense bodies" could be observed sporadically in these vesicles.

Animals↗
PubMed1975

[Histocompatibility-antigens in hay fever (author's transl)].

HL-A antigens have been determined in 110 not related Caucasian patients from southwest Germany suffering from hay fever and in 353 blood donors from the same area. Gene-frequencies and haplotype-frequencies of these 2 groups were compared, deviations within various specific allergy groups were investigated taking into consideration associated diseases. Patients suffering from hay fever showed a significant increase in frequency of W 19 and a significant decrease in HL-A8. Increase of W 19 was most evident in persons who became sick before the 16th year of age and in those who showed asthmatic symptoms in addition to those of hay fever. HL-A8 is significantly decreased only in persons who became sick after the 16th year of age. Found differences in haplotype-frequencies need further confirmation in larger studies. A relationship between changes of HL-A frequencies in hay fever due to special pollen allergies could not be determined.

Adolescent↗