PubMed Health⌕ Search

Biomedical subjects

C W Pool

Publications and source records attributed to C W Pool.

At least 55 records · Page 3Linked to original sources
PubMed1984

The dopaminergic innervation of the supraoptic and paraventricular nucleus. A light and electron microscopical study.

An antiserum that has been raised against glutaraldehyde-conjugated dopamine was used to demonstrate specifically dopamine in the rat hypothalamus. This dopamine antiserum permitted an optimal fixation with glutaraldehyde and therefore enabled the simultaneous light and electron microscopic immunocytochemical localization of dopamine. It was demonstrated that the paraventricular and supraoptic nuclei of the hypothalamus were innervated by thin dopaminergic fibers, in contrast to the suprachiasmatic nucleus, which hardly received any dopaminergic input. Ultrastructural observations revealed that the dopamine fibers terminated synaptically on the magnocellular neurons and their processes. It is concluded that the present results may explain the effect of centrally injected dopamine on vasopressin and oxytocin release. In the dopamine-containing terminals the reaction product was frequently observed in 90 nm dense core vesicles and around clear vesicles.

Animals↗
PubMed1984

First demonstration of highly specific and sensitive antibodies against dopamine.

Dopamine was coupled to bovine serum albumin (BSA) with glutaraldehyde, precautions were taken in order to preserve the catechol ring. After injection of this immunogen into rabbits, anti-dopamine antibodies were obtained and tested using radioimmunochemical binding studies and adsorption to catecholamine covered sepharose beads. A good correlation was found between the results of the different test systems, allowing us to visualize dopamine specifically in glutaraldehyde-fixed rat brains.

Animals↗
PubMed1984

Quantification of antiserum reactivity in immunocytochemistry. Two new methods for measuring peroxidase activity on antigen-coupled beads incubated according to an immunocytoperoxidase method.

Antigens covalently coupled to agarose beads provide a matrix for an economical, sensitive, and quantitative immunocytochemical detection of antiserum bindings potencies. Despite some very powerful features (e.g., the ability to control the outcome of a solid phase adsorption on the same matrix), the use of this technique is not very widespread when compared with the other enzyme-linked immunosorbent assay (ELISA) techniques. The main reason for this is the necessity for rather laborious measurements of the immunocytochemical tracer on individual beads. A description of two new methods for the batch measurement of the peroxidase activity on immunoperoxidase incubated antigen-coupled beads is presented. The first method involves the measurement of the diaminobenzidine (DAB) extinction from a large number of beads with a scanning microspectrophotometer. In the second method, during the peroxidase reaction, the beads are incubated with o-phenyldiamine (OPD), which is soluble both in the reduced and oxidized form, whereby absorbance measurements of the supernatant of the beads in a normal spectrophotometer are possible. The sensitivity and the quantitative relation between bound first antibody and absorbance are compared for both methods. From the two immunoperoxidase procedures used (the three step peroxidase-antiperoxidase and the two-step peroxidase conjugate procedure) only the latter met the conditions for a quantitative (first) antibody assay.

Animals↗
PubMed1983

Fixation and immunoperoxidase staining of oligopeptides after isoelectric focusing in thin polyacrylamide slab gels.

In this paper a new method for immunological detection of small peptides after isoelectric focusing in thin (200 micron) polyacrylamide slab gels is presented. The peptides are immobilized immediately after focusing by pressing a sheet of glutaraldehyde-impregnated filter paper onto the gel. By this procedure, the gel adheres to the paper and this press-blot can be stained using immunoperoxidase staining procedures. Using the two-step peroxidase conjugate and the three-step peroxidase-antiperoxidase method, several oligopeptides could be visualized after focusing. The detection limit of this method appears to be in the nanogram range.

Acrylic Resins↗
PubMed1983

Enkephalin immunoreactivity in synaptoid elements on glial cells in the rat neural lobe.

Opioid peptides were localized in fibres of the rat neural lobe using various immunocytochemical methods at the light- and electron-microscopical level. Leu-enkephalin immunoreactivity was present in beaded fibres distributed throughout the neural lobe. These fibres surround the neurohypophyseal glial cells (pituicytes) and make synaptoid contacts upon their soma and processes. The reaction product was localized both in dense-core vesicles of about 100 nm in diameter and diffusely spread over the cytoplasm. No arguments in support of the co-existence of enkephalins and the neurohypophyseal hormones vasopressin and oxytocin in the same terminal were found. It is suggested that pituicytes might mediate the inhibitory effect of opiod peptides on vasopressin and oxytocin release from the neural lobe.

Animals↗
PubMed1983

Immunohistochemical detection of O6-ethyldeoxyguanosine in the rat brain after in vivo applications of N-ethyl-N-nitrosourea.

An immunohistochemical procedure was developed which allows the localization of the DNA lesion O6-ethyldeoxyguanosine (O6-EtdGuo) within tissues and organs. The method permits the detection of 24,000 residues of O6-EtdGuo per diploid nucleus. We have used this procedure to localize N-ethyl-N-nitrosourea (ENU)-induced O6-EtdGuo in the rat brain. Shortly after a single injection of ENU, we observed O6-EtdGuo in most or all of the rat brain nuclei. After repeated injections of small doses of ENU, with intervals of 1 or 2 weeks between the injections and between the last injection and sacrifice, we could demonstrate O6-EtdGuo only in part of the rat brain nuclei. Oligodendrocytes, granular neurons and endothelial cells, and part of the pyramidal neurons and astrocytes had accumulated O6-EtdGuo, while in all other cells this lesion was not detectable after repeated injections of small doses of ENU. We found no obvious correlation between the putative sensitivity of rat brain cells to tumor induction and the accumulation of O6-EtdGuo in their DNA.

Animals↗
PubMed1982

The distribution of vasotocin and isotocin in the brain of the rainbow trout.

The distribution of vasotocin and isotocin in the brain of the rainbow trout Salmo gairdneri was investigated by the unlabeled antibody enzyme method, by using purified antisera against arginine vasotocin and isotocin. In the preoptic nucleus no clear differences were observed in the distribution of vasotocin- and isotocin-containing cells. Vasotocin and isotocin innervation was found in most brain regions, though in general isotocin fibers were much more abundant. The area dorsalis pars medialis of the telencephalon, the saccus dorsalis, and the basal part of the nucleus recessus posterioris were found to be innervated by vasotocin and scarcely by isotocin fibers. In the nucleus habenularis, the nucleus recessus lobus lateralis, the nucleus preglomerulosus pars medialis, and the tectum mesencephali isotocin fibers prevailed. These findings in the trout brain are compared with the vasopressin and oxytocin innervation of the rat brain.

Animals↗
PubMed1982

Differentiation of muscle fiber types in the teleost Brachydanio rerio, the zebrafish. Posthatching development.

The trunk musculature of adult zebrafishes contains three major fiber types: adult red, intermediate, and white; and two minor populations: red muscle rim and scattered intermediate fibers. In this paper, the post hatching development of these muscle fiber types was studied by means of immunohistochemistry, using anti-myosin sera. Just hatched larvae contain two muscle fiber populations: embryonic red and white, which give rise to the red muscle rim and the intermediate fibers respectively. Adult red fibers arise post hatching as a new separate population with distinct myosin properties. The differentiation of these fiber types occurs within the first four weeks after fertilization, when the adult pattern of peripheral axon bundles has become established. Differences in the muscle fiber type composition between the midbody and the tail myotomes become apparent in two month old fries. The number of scattered intermediate fibers increases from rostral to caudal, the opposite holds for the red muscle rim fibers. The red and intermediate area is triangular in the midbody; in the tail part it is stretched out along the lateral surface of the myotomes. These changes are considered as adaptations to improve the efficiency of the swimming performance.

Animals↗
PubMed1982

Effects of immobilization and partial denervation on the differentiation of muscle fiber types in the Zebrafish, Brachydanio rerio.

In this study we tested the effects of immobilization and of spinal cord lesion on the differentiation of muscle fiber types in the myotomal muscle of the zebrafish. We found that the differentiation of embryonic red and white muscle fibers occurs in immobilized as well as in denervated myotomes of zebrafish embryos. Intermediate and adult red muscle fibers are not formed in denervated myotomes of larvae. Adult zebrafishes with spinal cord lesions in the anal region show abnormal undulating movements in the rostral part of the body. This change in muscle activity correlates with an increase in the number of intermediate scattered fibers. We conclude that direct contact with spinal cord motorneurons is not necessary for the differentiation of embryonic red and white fibers. The differentiation of intermediate muscle fibers is under extrinsic control. The factors that determine the formation of adult red fibers are not yet clear.

Animals↗
PubMed1982

Calculation and registration of the same motor unit action potential.

In order to increase insight into the electrical phenomena of active motor units, a computer simulation model has been developed. With this model motor unit action potentials (MUAPs) have been calculated. The model has been based on the superposition of the muscle fibre potentials of the fibres of one motor unit. For verification, calculated MUAPs have been compared with the matching recorded MUAPs. During experiments one motor unit was stimulated and the MUAP of this unit was measured with intramuscular wire electrodes. After the experiments the positions of the activated fibres of this unit and of the electrodes were determined by means of histochemical techniques. Other parameters were derived from other experiments or the literature. Using the obtained set of parameters in the model MUAPs were calculated. These MUAPs were compared with the measured MUAPs. From this comparison it has been concluded that the model predicts the MUAP to an appreciable degree. The results clearly show the dominating effect of muscle fibres in close vicinity of the electrode and the important effect of the activation moment of those fibres on the shape of the MUAP.

Action Potentials↗
PubMed1980

An immune histochemical and enzymic characterization of the muscle fibres in myotomal muscle of the teleost Brachydanio rerio, Hamilton-Buchanan.

The myotomal muscles of teleosts have a complex internal structure. For a better understanding of the functional anatomy of these muscles we analysed the myofibrillar properties of the myotomal muscle fibres in a small teleost: Brachydanio rerio, the zebrafish. By immune histochemical techniques we discerned 4 types of muscle fibres: red lateral fibres, red muscle rim (RMR) fibres, intermediate fibres and white fibres, each with a distinct type of heavy chain myosin. In addition we discerned 2 populations of muscle fibres in which the myofibrils contain mixtures of white and intermediate heavy chain myosin. The immune histochemical classification correlates well with an enzyme histochemical classification of the muscle fibres. In order to find out whether the immune and enzyme histochemical differences correlate with differences in dynamic properties of the muscle fibres, we analysed the ATP-ase activity of glycerinated muscle fibres. 3 of the 5 muscle fibre types which are discriminated by immune histochemical methods could thus be analysed. Differences in histochemical reactions coincide with differences in ATP-ase activities of the glycerinated muscle fibres. 2 classes of muscle fibres were homogeneous as to the ATP-ase activity of their muscle fibres. The 3rd class, the white fibres, could be divided in 2 populations with slightly different ATP-ase activities. The results indicate that the myotomal muscle fibre population is much more heterogeneous than has been considered thusfar. This heterogeneity may allow an almost continuous range of contraction speeds in the myotomal muscle.

Adenosine Triphosphatases↗
PubMed1980

Myofibrillar differences among mammalian skeletal muscle fibres at the ultrastructural level. A comparison of immunocytochemical and morphometrical parameters.

In the light microscope two types (I, II) of skeletal muscle fibres can be distinguished with antibodies against myosin isozymes. At the ultrastructural level a difference in Z-line width has led to muscle fibre classification. In this study we distinguish at the ultrastructural level between type I and type II fibres of the M. soleus and M. plantaris of adult mice using ultracryosections with immuno-ferritin and antisera against myosin isozymes. Muscle fibres of the M. plantaris are identified as type II fibres and the fibres of the M. soleus are divided in type I and type II fibres. In the immunologically identified fibres the filament overlap in the Z-line was measured. The type II fibres of the M. plantaris have narrow Z-lines, whereas type I and type II fibres of the M. soleus have wide Z-lines. We conclude that a classification of fibres based on Z-line width differs from the type I/type II classification. The antimyosin antibodies react exclusively with the A-band. In serial sections the myosin isozymes can be identified unambiguously. This is a prerequisite for further studies of myosin isozyme distribution in "mixed" muscle fibres.

Animals↗
PubMed1979

Quantitative succinate-dehydrogenase histochemistry. I. A Methodological study on mammalian and fish muscle.

In enzyme histochemistry formazan production can be used as a measure for oxidative enzyme activity. The formazan deposits can be measured quantitatively per cell with a scanning and integrating microspectrophotometer. Optimal conditions are described for the estimation of histochemical succinate dehydrogenase activity in sections of fish bodymusculature and mouse soleus and plantaris muscle. It is shown that when proper measuring conditions are chosen a ditetrazolium salt (TNBT) can be used in quantitative enzyme histochemistry and that the optimal conditions for the histochemical succinate dehydrogenase reaction in muscle fibres of fish and mouse muscle are somewhat different for these two species. The differences in pH, temperature and succinate sensitivity are the most prominent.

Animals↗
PubMed1979

Quantitative succinate-dehydrogenase histochemistry. II. A comparison between visual and quantitative msucle fibre typing.

Most muscles exhibit a mosaic pattern of staining intensities of their muscle fibres after the histochemical reaction for succinate dehydrogenase (SDH). Visually these muscle fibres are usually classified into three groups: with low (A-fibres), intermediate (B-fibres), and high (C-fibres) enzymatic activity (staining intensity). Cytospectrophotometric methods were employed to investigate whether discrete groups of muscle fibres could be discerned, comparable to those found after the visual classification. The classifications were based on quantitative parameters of the total absorbance per cell and the distribution of the coloured endproduct over the fibre cross area.

Animals↗
PubMed1979

Quantitative succinate-dehydrogenase histochemistry. III. Variations in histochemical succinatedehydrogenase activity in different cross-sections of the same muscle fibre.

The variation in histochemical SDH-activity at different levels in the same muscle fibre was determined in muscle fibre cross-sections both by visual classification and quantitative determination of the formazan-deposits. This work resulted in a confirmation of the earlier micro-biochemical studies of Spamer AND Pette (1977, 1979) and Lowrey et al. (1978) that the activity of enzymes of the citric acid cycle is not homogeneously distributed in a muscle fibre over its entire length. In addition it is shown that the observed variations in histochemical SDH-activity strongly interfere with the visual muscle fibre typing. Some of the possible causes for these variations in histochemical SDH-activity (section-thickness, presence of the motor-endplate) and the implications of these findings for the relation between histochemical characteristics and functional properties of the muscle fibres are briefly discussed.

Animals↗
PubMed1979

Differentiation of the musculature of the teleost Brachydanio rerio. II. Effects of immobilization on the shape and structure of somites.

The development of the shape and structure of somites in the teleost Brachydanio rerio was studied in embryos under normal conditions and in immobilized embryos. Three different immobilization methods were applied: enclosure in agar, a glass rod in the neural tube and anaesthesia in MS-222. When the performance of the lateral body movements is prevented, the shape development of the somites in embryos and young larvae becomes reversed. When the agar-immobilization is terminated, the larvae resume their normal movements. In about 10 days, the shape of the somites is again as in control larvae. We conclude, that the lateral body movements have both a shape-determining and a shape-stabilizing role during the early stages of somite morphogenesis. It is suggested that in normal embryos differences in shortening between lateral and medial muscle fibres, cause differences in longitudinal growth of the muscle fibres and that the oblique muscle fibre arrangement is a consequence of these differences in growth. In immobilized embryos and larvae, the longitudinal growth of the muscle fibres is decreased. Also the difference in the longitudinal growth rate between lateral and medial muscle fibres diminishes in all somites. We conclude that for the normal morphogenesis of the somites the performance of the specific function, that is to bring about lateral body movements, is required. We suggest, that the impact of the lateral body movements on the development of the structure of the somites is mediated through adaptive growth of the muscle fibres. The suggestion may also apply to the development of the pinnate structure of muscles of higher vertebrates.

Agar↗