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H K Feirabend

Publications and source records attributed to H K Feirabend.

At least 19 recordsLinked to original sources
PubMed1998

Preservation and staining of myelinated nerve fibers.

Six procedures are given for preservation of myelinated nerve fibers for light or electron microscopic studies. These procedures fall into two main categories: those with and those without aldehyde fixation. Essentially different effects are attained by application of tannic acid, saline, microwave or conventional heating, or a decreased temperature. All procedures end in osmication. Three main aspects of myelinated fiber morphology are taken into account when judging the quality of their preservation: axon, myelin sheath, and axon/myelin coherence. Each aspect can be preserved excellently, but always in combination with a less superior quality of the other two aspects. Superior myelin quality is attained using microwave irradiation, either with aldehydes to which tannic acid is added or without aldehyde fixatives. Superior axon quality is attained with aldehydes and (conventional) heating. Axon/myelin coherence is best preserved by decreasing the temperature during the rinse with saline. Another two procedures provide good, though less superior, preservation of both axon and axon/myelin coherence. Next, the fixed tissue is embedded in plastic blocks from which semithin and ultrathin plastic sections are cut for light and electron microscopy, respectively. In addition to the standard procedure for toluidine blue staining on semithin sections, two microwave-supported procedures are described, which can be used as alternatives if the staining result is unsatisfactory. Furthermore, a toluidine blue staining procedure is described for glycol methacrylate (GMA)-embedded material, which can be used if larger sections are needed.

Aldehydes↗
PubMed1996

White matter of the cerebellum of the chicken (Gallus domesticus): a quantitative light and electron microscopic analysis of myelinated fibers and fiber compartments.

Low magnification light microscopic examination of the white matter in appropriately stained avian and mammalian cerebellum reveals a mediolateral succession in which areas of large, heavily myelinated fibers alternate with areas containing nearly exclusively small fibers. A large fiber accumulation (LFA) and its medially adjoining small fiber area (SFA) form a fiber compartment, which, with related parts of cortex and central nuclei, constitutes a so-called cerebellar module. The composition and the apparent mediolateral heterogeneity of cerebellar fiber compartments was quantified in the chicken by morphometrical analysis of myelinated fiber profiles in light (LM) and electron (EM) microscopic micrographs. In LM versus EM, approximately 37% of the myelinated fiber population is neglected. This deficit concerns profiles that are smaller than 1.2 micron2 (diameter < 1.2 microns). EM analysis is therefore considered a prerequisite and forms the main part of this study. The myelinated fiber population has a left-skewed log normal size distribution. Ninety-nine percent of the myelinated fibers fall within the range of 0.1 to 20 microns2 (diameter = 0.4-5.0 microns) and 90% are even smaller than 7 micron2 (diameter < 3.0 microns). Small fibers are abundant in both parts of the compartment. Statistical comparisons provide quantitative confirmation of the LM distinction of LFAs and SFAs. It appears, moreover, that, apart from typical LFAs and SFAs, transitional zones rather than sharp borders can be distinguished between the two. The medial border of the LFA appears to be more sharply defined than its lateral border. Distinct mediolateral fluctuations were found with respect to fiber density (166-243 fibers/1,000 microns2), mean profile area (2.4-4.0 microns2), and interspace (31-47%). These differences reflect the contrast between LFA (lower density, larger mean profile area) and SFA (higher density, smaller mean profile area). The interspace discriminates less well between LFA and SFA but is often smaller in the LFA and larger in the SFA. The presented quantitative characteristics of mediolateral heterogeneity in the cerebellar fiber layer can be used as reference for morphometric studies on the different fiber systems of the cerebellar white matter and the functional organization of the compartments.

Animals↗
PubMed1994

The rostrocaudal organization in the dorsal root ganglia of the rat: a consequence of plexus formation?

The dorsal root ganglia (DRGs) of the rat have a rostrocaudal organization. This organization can most easily be demonstrated in fetal and neonatal rats because the spatial relationships of their DRGs are maintained better in tissue sections than those of mature rats. This review is concerned with the way in which the rostrocaudal organization of the DRGs is generated. Wheat germ agglutinin--horseradish peroxidase/horseradish peroxidase labeling of peripheral nerves of the brachial and lumbar plexuses shows that the position of the somata of the sensory neurons of the labeled nerves can be restricted to rostral or caudal halves of DRGs. Labeling of the thoracic nerve or its branches always results in labeling throughout the entire thoracic DRG. After application of the marker to forelimb nerves, it was observed that whenever a DRG is labeled only partially, its spinal nerve is correspondingly labeled partially as well. These data suggest that the rostrocaudal organization in the DRG is related to the formation of the plexuses. During development nerve fibers can be segmentally labeled, using the subdivision of the DRGs into a rostral and a caudal half to keep together as they find their way through the plexus. Application of label to forelimb skin, hindlimb skin and even thoracic skin can result in labeling of rostral or caudal halves of a DRG. A possible explanation might be that each dermatome can be divided into a skin area innervated by the rostral half of a DRG and a skin area innervated by the caudal half of the same dorsal root ganglion. In the rat, the segmental sensory innervation of muscles during development has not yet been investigated. The question of whether the segmental unit of innervation of a muscle is a whole DRG or half a DRG therefore still remains unanswered.

Animals↗
PubMed1994

Preservation of myelinated fibers for electron microscopy: a qualitative comparison of aldehyde fixation, microwave stabilisation and other procedures all completed by osmication.

A qualitative comparison was made of a variety of electron microscopic preservation methods for nervous tissue, especially with respect to myelinated fiber areas. The methods studied were aldehyde perfusion/immersion fixation, aldehyde-tannic acid immersion fixation (stimulated by either microwave or conventional heating), microwave stabilisation, saline treatment with conventional heating (all with secondary osmication), and primary osmication. For all methods three morphological aspects, the ultrastructural quality of myelin sheath and axon and the coherence between the two were judged separately. It appears that the best version of each method studied is capable of providing a good overall ultrastructural result but always shows a preference for one or two of the three separate morphological aspects. When aiming at good axon quality together with good axon/myelin coherence, aldehyde perfusion/immersion, saline treatment or primary osmication are almost equivalent. Microwave stabilisation, on the other hand, can be chosen when good myelin quality has to be combined with good axon quality. For more specific purposes the following examples can be given. When excellent myelin quality is needed both microwave-stimulated aldehyde-tannic acid fixation or microwave stabilisation can be considered. When the preservation of the axon quality has priority the aldehyde-perfused tissue should be further immersed in a heated aldehyde-tannic acid solution. Primary osmication guarantees excellent axon/myelin coherence. Despite the differences in detail, a remarkable correspondence is stressed between the overall results of sometimes extremely different methods of tissue preservation. Probably they all guarantee a reliable reflection of the in vivo situation. With respect to the use of microwave irradiation for tissue preservation, it appeared that stabilisation procedures are rather capricious. However, if successful, the results are not inferior to those of aldehyde fixation.

Aldehydes↗
PubMed1993

Does microwave irradiation have other than thermal effects on glutaraldehyde crosslinking of collagen?

The effects of microwave irradiation (MWI) can theoretically be divided in thermal and non-thermal effects. Because there is still much debate on the contribution of non-thermal microwave effects, experiments were carried out in which the effects of isothermal microwave irradiation on glutaraldehyde (GA) crosslinking of native collagen membranes (NCM) is studied. A total of 20 strips of collagen membrane of porcine origin were isothermally irradiated in 300 ml of a 0.1 (w/w) GA solution, 10 strips at 4 degrees C, and 10 strips at 20 degrees C. A temperature controlled microwave oven (630W) was adapted to allow for simultaneous cooling of the fixation solution preventing the MWI to induce any measurable thermal effects. Any possible temperature variations were recorded employing continuous fiberoptic temperature measurement. Control experiments were carried out under the same (isothermal) fixation conditions, but without MWI. The crosslinking action of the GA was evaluated by determining the shrinkage temperature (Ts) of the collagen strips. No significant difference (p > 0.05) could be observed between the increase in (Ts) of the microwaved and the increase in Ts of the nonmicrowaved strips. The increase in Ts at 4 degrees C (c. 14 degrees C) was lower than that obtained at 20 degrees C (c. 16 degrees C). It was concluded that MWI induces no substantial nonthermal effect on enhancement of GA crosslinking of collagen at these temperatures.

Animals↗
PubMed1992

Does microwave irradiation have other than thermal effects on histological staining of the mammalian CNS? A light microscopical study of microwave stimulated staining under isothermal conditions in man and rat.

The question whether or not microwave irradiation exerts other than thermal effects on histological staining is still a matter of controversy. The present study was undertaken to reveal or reject such a so far hypothetical non-thermal irradiation effect. A device was developed, which enables exposure of histological sections or tissue pieces to microwave irradiation under isothermal conditions, i.e. with synchronous removal of the internal heat produced. Three classical neuroanatomical staining methods were tested on human and rat CNS. As control, identical procedures were performed without simultaneous microwave irradiation. The experiments were performed at three different temperature levels ranging from 5 to 50 degrees C. In none of the cases studied was a light microscopically appreciable difference observed between the microwave and non-microwave versions of a stain at the same temperature. The hypothesis of a separate non-thermal effect of microwave irradiation on histological staining is therefore rejected.

Animals↗
PubMed1991

Development of projections of primary afferent fibers from the hindlimb to the gracile nucleus: a WGA-HRP study in the rat.

The projection of primary afferent fibers to the gracile nucleus was studied during development. Injections of wheat germ agglutinin-horseradish peroxidase were made into the hindlimb of fetal, postnatal and adult rats. In most cases the sections were alternately stained for wheat germ agglutinin-horseradish peroxidase including counter stain with Neutral red and for acetylcholinesterase. At embryonic day 17 labelled fibers could be traced to the mid-cervical spinal cord but not further rostrally. At embryonic days E18 and E19 labelled fibers penetrate the rostral pole of the nucleus, which does not happen more caudally. At embryonic day E21 the caudal-most pole of the gracile nucleus still is not penetrated by labelled fibers. From postnatal day 1 onwards labelled fibers are found throughout the entire rostrocaudal extent of the gracile nucleus. These results suggest that primary afferent fibers from the hindlimb first grow to the rostral pole of the gracile nucleus and penetrate the rostral pole immediately upon their arrival. During further development more caudal parts of the gracile nucleus are gradually penetrated in a rostrocaudal fashion by primary afferent fibers of the hindlimb.

Afferent Pathways↗
PubMed1991

Microwave applications in classical staining methods in formalin-fixed human brain tissue: a comparison between heating with microwave and conventional ovens.

The quality of microwave adaptations of three classical neuroanatomical staining methods (the Nissl, Klüver-Barrera and Häggqvist stains) was tested on frozen serial sections from human brain specimens which has been stored for up to 10 years in 10% formalin. The conclusion was that the use of microwave irradiation reduces processing time and/or concentrations of the chemicals used, whereas the light microscopical quality of the stains considered is equal or improved as compared to their original counterparts. Next, a comparison was made between microwave adapted stains and classical procedures, which, except for the use of a conventional oven as heat source together with pre-heated solutions, were entirely identical. It appeared, that at light microscopical level no difference can be appreciated between the effect of internally (using microwave irradiation) and externally (using a conventional oven) supplied heat on the staining result.

Brain↗
PubMed1990

Evidence for a rostrocaudal organization in dorsal root ganglia during development as demonstrated by intra-uterine WGA-HRP injections into the hindlimb of rat fetuses.

The development of the sensory innervation of the rat hindlimb was studied with special attention to the dorsal root ganglia and the lumbar plexus. Injections of wheat germ agglutinin-horseradish peroxidase were made into the hindlimb of 30 rat fetuses of gestational ages ranging from embryonic day 15-18. Additionally wheat germ agglutinin-horseradish peroxidase was applied to the sciatic nerves of 8 neonatal rats and 3 adults. The saphenous nerves of 2 neonatal rats were labeled. Injections of wheat germ agglutinin-horseradish peroxidase (WGA-HRP) into the hindlimb of the fetuses result in completely and partially labeled dorsal root ganglia. Partial labeling always concerns the rostral or caudal part of a dorsal root ganglion. The associated dorsal roots of partially labeled dorsal root ganglia are also partially labeled in a corresponding rostrocaudal fashion. Reconstructions of the labeled nerves following injections into the hindlimb suggested that the somata of the sensory neurons of a particular nerve can be restricted to the rostral or caudal half of a dorsal root ganglion. For example: the rostral half of the fourth lumbar dorsal root ganglion belongs to the femoral nerve and its caudal half to the sciatic nerve. The results of application of wheat germ agglutinin-horseradish peroxidase to the central ends of the cut sciatic and saphenous nerves in neonatal rats confirmed these observations. So the rostrocaudal organization in the dorsal root ganglia stems from the distribution pattern of the peripheral nerves.

Animals↗
PubMed1990

Post-fixation horseradish peroxidase tracing in rat fetus and pups.

Horseradish peroxidase (HRP) has been shown to be applicable to fixed tissue in tracing projections in adult animals. This technique has several advantages in studying short projections in difficult attainable brain areas, especially with fetuses in utero. We have used this method to trace developing fibers (e.g., vestibulo-cerebellar connections) in rat fetuses and pups. It has been possible to make discrete and precise injections in any location. The quality of labeling by this method is distinctly related to the grade of fixation. Fixation grade determines how well HRP is anchored inside fibers and cell bodies. In optimally fixed preparations fibers and cell bodies are intensively stained with HRP up to over 3 mm from the center of an injection site. HRP is probably only taken up by damaged fibers so that the amount of fibers labeled is determined by the extent of the lesion caused by the injection pipette.

Animals↗
PubMed1990

Development of longitudinal patterns in the cerebellum of the chicken (Gallus domesticus): a cytoarchitectural study on the genesis of cerebellar modules.

The cytoarchitecture of the cerebellum has been studied in chicken embryos from day 3-20 using serial sections stained with cresylviolet, haematoxylin-eosin and toluidine blue. Three periods have been distinguished in cerebellar development on a basis of cytoarchitectonic characteristics. Of these periods the middle one, which lasts from the 8th to the 15th day, is marked by two subsequent transient longitudinal cytoarchitectonic patterns in the cortical anlage. The first pattern, which exists between days 8 and 11, consists of 4 longitudinal Purkinje cell clusters (of the first order) at either side of the midline. The second pattern, which is most distinct and complete during embryonic days 12-14, is caused by specific localizations of otherwise few, early inwardly migrating granule cells from the external cerebellar matrix (so-called granule raphes), which pass through the layer of Purkinje cell clusters of the first order and thus subdivide these latter into smaller entities: Purkinje cell clusters of the second order. The number of these latter (6 or 7 and 11 or 12 in the anterior and posterior lobes, respectively) correspond to the number of parasagittal modules, which can be discerned on a basis of the organization of fiber connections of the adult cerebellar cortex. Thanks to this similarity various hypotheses can be formulated concerning the significance of the transient cytoarchitectonic patterns in the primitive cortex for the genesis of the modular organization of the cerebellum.

Animals↗
PubMed1990

Somatotopic organization in the sensory innervation of the rat hindlimb during development, using half dorsal root ganglia as subsegmental units.

The aim of the present study was to determine the somatotopy of the sensory innervation of the rat hindlimb at the level of the dorsal root ganglia (DRGs) during the fetal and postnatal period. Injections of wheat germ agglutinin-horseradish peroxidase (WGA-HRP) were made into the hindlimb of fetal and postnatal rats. These injections result in completely and partially labeled DRGs. Partial labeling always concerns the rostral or caudal half of a DRG. Using half DRGs as subsegmental units, a description is given of a somatotopic organization of the sensory innervation of the rat hindlimb during development.

Animals↗
PubMed1988

Glial fiber pattern in the developing chicken cerebellum: vimentin and glial fibrillary acidic protein (GFAP) immunostaining.

The possible relation between glial fibers and the formation of longitudinal granule cell migration patterns that occur in the cerebellar anlage of the chicken was investigated by immunocytochemistry of vimentin (monoclonal antibody) and glial fibrillary acidic protein (polyclonal antibody against GFAP, PGF) on fixed and unfixed brain tissues. In addition, neuronal development was studied with a monoclonal antibody for neurofilament. Vimentin was present in radial and tangential fibers in the cerebellar anlage during granule cell migration in almost all parts of the anlage. However, no specific topographic relation of vimentin and GFAP to the migration pattern of granule cells was observed. In adults, Bergmann fibers and astroglia were stained with vimentin antiserum and not with GFAP antiserum. Conclusions are that radial fibers do not determine the formation of longitudinal cytoarchitectonic patterns in the chick cerebellum and that vimentin is the main cytoskeletal component of Bergmann fibers and astroglial cells in embryonic and adult chicken cerebellum.

Animals↗
PubMed1986

Myeloarchitecture of the cerebellum of the chicken (Gallus domesticus): an atlas of the compartmental subdivision of the cerebellar white matter.

A myeloarchitectonic atlas of the longitudinal (or mediolateral) subdivision of the cerebellum of the chicken (white Leghorn) was prepared from serial Häggqvist or toluidine-blue-stained sections of five animals. This myeloarchitectonic subdivision is based on the alternate occurrence of large fiber accumulations (LFAs) and small fiber areas (SFAs) in the cerebellar white matter and allows the distinction of a number of parasagittal fiber compartments, each of which consists of a medial LFA and a lateral SFA. The compartmental subdivision of the cerebellar white matter in mammals and birds derives its importance from the fact that essentially it corresponds to the organization of the afferent and efferent connections of the cerebellar cortex. The simple structure of the avian cerebellum makes it ideally suited for a complete description of its compartmental subdivision and may serve as a natural system of coordinates in future anatomical and physiological studies. The number of fiber compartments that can be counted in the chicken cerebellum on either side of the midline varies from six (in the narrowest folium I) to nine (in the widest folia IX and X) and is approximately the same as in mammals, in which a maximum of eight or ten compartments can be recognized. On the basis of the organization of its myeloarchitecture and the otherwise relatively scarce data on the organization of the connections of its cortex, it can, therefore, be postulated that the avian cerebellum is the homologue of the entire mammalian cerebellum. In addition, the present knowledge of the connections of the cerebellar cortex in birds indicates that the avian compartments 1-3 may correspond to the mammalian compartments A1, A2, and A3 (or X), whereas the avian compartment 4 or 5 (or both) may represent the mammalian B compartment. Lack of further anatomical data so far precludes conclusions on a possible homology between the avian compartments 6-9 and the mammalian C and D compartments.

Animals↗
PubMed1985

A 3H-thymidine autoradiographic study of the development of the cerebellum of the White Leghorn (Gallus domesticus): "evidence for longitudinal neuroblast generation patterns".

Dynamic aspects of the development of the cerebellum of the white Leghorn (Gallus domesticus) were examined using 3H-thymidine autoradiography. A single dose of 25 microCi 3H-thymidine was given to embryos varying in age from 0-18 days. The embryos were all studied before hatching, either after short or after long survival times. It appeared that the superficial part of the outer mantle layer (OML-s, or called external granular layer, egl) is histologically present at day 6, but starts its activity as a secondary matrix at day 7, probably due to activation by a secondary influx of cells from the ventricular neuro-epithelium. It was also demonstrated that Purkinje cells and cells of the central cerebellar nuclei are produced by the ventricular neuro-epithelium mainly at days 3, 4 and 5. No birth of these cells was observed beyond day 5. In addition, a relationship was found between the birth patterns of Purkinje cells and cells of the central cerebellar nuclei and the longitudinal cytoarchitectonic patterns as observed in normal Nissl stained material. It was concluded that these birth patterns are an early contribution to the establishment of the longitudinal organization of the cerebellum.

Animals↗