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  • Articles  (36)
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  • Springer  (36)
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  • 1
    Electronic Resource
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    Springer
    Numerische Mathematik 31 (1978), S. 175-182 
    ISSN: 0945-3245
    Keywords: AMS(MOS): 65 L05 ; CR: 5.17
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Summary When variable stepsize variable formula methods (VSVFM's) are used in the solution of systems of first order differential equations instability arises sometimes. Therefore it is important to find VSVFM's whose zerostability properties are not affected by the choice of both the stepsize and the formula. The Adams VSVFM's are such methods. In this work a more general class of methods which contains the Adams VSVFM's is discussed and it is proved that the zero-stability of the class is not affected by the choice of the stepsize and of the formula.
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  • 2
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    Numerische Mathematik 30 (1978), S. 369-383 
    ISSN: 0945-3245
    Keywords: AMS (MOS): 65L05, 65M10, 65M15, 65M20, 65N15, 65N30 ; CR: 5.17
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Summary Backward differentiation methods up to orderk=5 are applied to solve linear ordinary and partial (parabolic) differential equations where in the second case the space variables are discretized by Galerkin procedures. Using a mean square norm over all considered time levels a-priori error estimates are derived. The emphasis of the results lies on the fact that the obtained error bounds do not depend on a Lipschitz constant and the dimension of the basic system of ordinary differential equations even though this system is allowed to have time-varying coefficients. It is therefore possible to use the bounds to estimate the error of systems with arbitrary varying dimension as they arise in the finite element regression of parabolic problems.
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  • 3
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    Numerische Mathematik 31 (1978), S. 1-16 
    ISSN: 0945-3245
    Keywords: AMS(MOS): 65N30 ; CR: 5.17
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Summary We study the mixed finite element approximation of variational inequalities, taking as model problems the so called “obstacle problem” and “unilateral problem”. Optimal error bounds are obtained in both cases.
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  • 4
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    Numerische Mathematik 31 (1978), S. 131-152 
    ISSN: 0945-3245
    Keywords: AMS(MOS): 65L05 ; CR: 5.17
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Summary The right-hand sides of a system of ordinary differential equations may be discontinuous on a certain surface. If a trajectory crossing this surface shall be computed by a one-step method, then a particular numerical analysis is necessary in a neighbourhood of the point of intersection. Such an analysis is presented in this paper. It shows that one can obtain any desired order of convergence if the method has an adequate order of consistency. Moreover, an asymptotic error theory is developed to justify Richardson extrapolation. A general one-step method is constructed satisfying the conditions of the preceding theory. Finally, a simplified Newton iteration scheme is used to implement this method.
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  • 5
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    Numerische Mathematik 31 (1978), S. 49-61 
    ISSN: 0945-3245
    Keywords: AMS (MOS): 65N20 ; CR: 5.17
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Summary There are currently several highly efficient methods for solving linear systems associated with finite difference approximations of Poisson's equation in rectangular regions. These techniques are employed to develop both direct and iterative methods for solving the linear systems arising from the use ofC 0 quadratic orC 1 cubic tensor product finite elements.
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  • 6
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    Numerische Mathematik 29 (1978), S. 381-396 
    ISSN: 0945-3245
    Keywords: AMS(MOS): 65L05 ; CR: 5.17
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Summary In this paper, a general class ofk-step methods for the numerical solution of ordinary differential equations is discussed. It is shown that methods with order of consistencyq have order of convergence (q+1) if a very simple condition is satisfied. This result gives a new aspect to previous results of Spijker; it also serves as a starting point for a new theory of cyclick-step methods, completing an approach of Donelson and Hansen. It facilitates the practical determination of high-order cyclick-step methods, especially of stiffly stable,k-step methods.
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  • 7
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    Numerische Mathematik 29 (1978), S. 409-424 
    ISSN: 0945-3245
    Keywords: AMS (MOS): 65LO5 ; CR: 5.17
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Summary In a recent article [2] Frank and Überhuber define and motivate the method of iterated defect correction for Runge-Kutta methods. They prove a theorem on the order of that method using the theory of asymptotic expansions. In this paper we give similar results using the theory of Butcher series (see [4]). Our proofs are purely algebraic. We don't restrict our considerations to Runge-Kutta methods, but we admit arbitrary linear one-step methods. At the same time we consider more general defect functions as in [2].
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  • 8
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    Numerische Mathematik 29 (1978), S. 209-226 
    ISSN: 0945-3245
    Keywords: AMS(MOS): 65L 10 ; CR: 5.17
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Summary In this paper we give a simple stability theory for finite difference approximations to linear ordinary boundary value problems. In particular we consider stability with respect to a maximum norm including all difference quotients up to the order of the differential equation. It is shown that stability in this sense holds if and only if the principal part of the differential equation is discretized in a “stable way”. This last property is characterized by root conditions which we prove to be satisfied for some classes of finite difference schemes. Our approach simplifies and generalizes some known results of the literature where Sobolev norms or merely the maximum norm are used.
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  • 9
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    Numerische Mathematik 29 (1978), S. 397-407 
    ISSN: 0945-3245
    Keywords: AMS (MOS): 31-04, 65N05 ; CR: 5.17
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Summary A transformation method is developed which may be used to solve various types of boundary value problems on three-dimensional regions with an arbitrary boundary. The implementation of the method is illustrated in the solution of a potential flow problem. All computations are performed on a cubic mesh in a rectangular region.
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  • 10
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    Numerische Mathematik 29 (1978), S. 425-443 
    ISSN: 0945-3245
    Keywords: AMS(MOS): 65J05, 65L99 ; CR: 5.17
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Summary Recently, a number of closely related techniques for error estimation and iterative improvement in discretization algorithms have been proposed. In this article, we expose the common structural principle of all these techniques and exhibit the principal modes of its implementation in a discretization context.
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  • 11
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    Numerische Mathematik 30 (1978), S. 93-101 
    ISSN: 0945-3245
    Keywords: AMS(MOS): 65L10 ; CR: 5.17
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Summary We consider non-inverse positive differential operators of the second order and show that error estimates can be obtained through methods of inverse positivity alone. This means a significant simplification if the operator has only one negative eigenvalue. In addition we show how to obtain Range-Domain implications for operators with mixed boundary conditions.
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  • 12
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    Numerische Mathematik 31 (1978), S. 359-375 
    ISSN: 0945-3245
    Keywords: AMS (MOS): 65L10 ; CR: 5.17
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Summary For the numerical solution of two-point boundary value problems a shooting algorithm based on a Taylor series method is developed. Series coefficients are generated automatically by recurrence formulas. The performance of the algorithm is demonstrated by solving six problems arising in nonlinear shell theory, chemistry and superconductivity.
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  • 13
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    Numerische Mathematik 29 (1978), S. 269-285 
    ISSN: 0945-3245
    Keywords: AMS (MOS): 65 M 99 ; CR: 5.17
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Summary Several extrapolation procedures are presented for increasing the order of accuracy in time for evolutionary partial differential equations. These formulas are based on finite difference schemes in both the spatial and temporal directions. One of these schemes reduces to a Runge-Kutta type formula when the equations are linear. On practical grounds the methods are restricted to schemes that are fourth order in time and either second, fourth or sixth order in space. For hyperbolic problems the second order in space methods are not useful while the fourth order methods offer no advantage over the Kreiss-Oliger method unless very fine meshes are used. Advantages are first achieved using sixth order methods in space coupled with fourth order accuracy in time. The averaging procedure advocated by Gragg does not increase the efficiency of the scheme. For parabolic problems severe stability restrictions are encountered that limit the applicability to problems with large cell Reynolds number. Computational results are presented confirming the analytic discussions.
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  • 14
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    Numerische Mathematik 29 (1978), S. 329-344 
    ISSN: 0945-3245
    Keywords: AMS(MOS): 65M20 ; CR: 5.17
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Summary The method of lines is used to solve Poisson's equation on an irregular domain with nonlinear or free boundary conditions. The partial differential equation is approximated by a system of second order ordinary differential equations subject to multi-point boundary conditions. The system is solved with an SOR iteration which employs invariant imbedding for each one dimensional problem. An application of the method to a boundary control problem and to a free surface problem arising in electrochemical machining is described. Finally, some theoretical convergence results are presented for a model problem with radiative boundary conditions on fixed boundaries.
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  • 15
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    Numerische Mathematik 30 (1978), S. 385-409 
    ISSN: 0945-3245
    Keywords: AMS(MOS): 65 L05 ; CR: 5.17
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Summary High order implicit integration formulae with a large region of absolute stability are developed for the approximate numerical integration of both stiff and non-stiff systems of ordinary differential equations. The algorithms derived behave essentially like one step methods and are demonstrated by direct application to certain particular examples.
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  • 16
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    Numerische Mathematik 30 (1978), S. 267-279 
    ISSN: 0945-3245
    Keywords: AMS(MOS): 65L10 ; CR: 5.17
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Summary A finite element method using piecewise polynomials of degree ≦k is used to approximate the problem εu″+u′=f, ε〉0 a small parameter. A very irregular mesh is used. On this mesh error estimates of order0(h k+1) are obtained uniformly in ε,h the maximum stepsize, fork≧2. The condition number of the system of linear equations one has to solve in order to get the approximation is estimated. Extension of the results to more complicated problems is briefly indicated. Finally, a numerical example is given.
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  • 17
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    Numerische Mathematik 30 (1978), S. 25-38 
    ISSN: 0945-3245
    Keywords: AMS (MOS): 65L05 ; CR: 5.17
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Summary Brown introducedk-step methods usingl derivatives. We investigate for whichk andl the methods are stable or unstable. It is seen that to anyl the method becomes unstable fork large enough. All methods withk≦2(l+1) are stable. Fork=1,2,..., 18 there exists aλ k such that the methods are stable for anyl ≧λ k and unstable for anyl 〈λ k . Theλ k are given.
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  • 18
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    Numerische Mathematik 30 (1978), S. 103-116 
    ISSN: 0945-3245
    Keywords: AMS(MOS): 65N30 ; CR: 5.17
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Summary We consider some equilibrium finite element methods for two-dimensional elasticity problems. The stresses and the displacements are approximated by using piecewise linear functions. We establishL 2-estimates of orderO(h 2) for both stresses and displacements.
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  • 19
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    Numerische Mathematik 30 (1978), S. 411-414 
    ISSN: 0945-3245
    Keywords: AMS(MOS): 65L99 ; CR: 5.17
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Summary It is shown that Liapunov functions may be used to obtain error bounds for approximate solutions of systems of ordinary differential equations. These error bounds may reflect the behaviour of the error more accurately than other bounds.
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  • 20
    ISSN: 1432-2048
    Keywords: Avena ; Immunocytochemistry ; Phytochrome
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Phytochrome of oat (Avena sativa L., cv. Garry) coleoptile cells in the red-light-absorbing form, Pr, is diffusely distributed while after conversion to the far-red-light-absorbing form, Pfr, it is observed only in very small areas within the cell. Comparison of phytochrome photoversibility measurements to the distribution of the pigment within the cell indicates that the spectral assay is not influenced by the observed compartmentalization of the chromoprotein. However, the observed compartmentalization of phytochrome is correlated with a loss in spectrophotometrically detectable Pr.
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  • 21
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    Cell & tissue research 186 (1978), S. 399-412 
    ISSN: 1432-0878
    Keywords: Pituitary gland ; Dog ; Pars distalis ; Thyrotropin (TSH) ; Immunocytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Using the immunoperoxidase technique and antisera to the specific beta (β) subunits of bovine and rat TSH1, selective immunocytochemical staining was localized in a specific cell population in the pars distalis of the dog pituitary gland. These TSH cells were found to be positive to aldehyde fuchsin, alcian blue, periodic acid-Schiff (PAS) and aniline blue. With the performic acidalcian blue (pH 0.2) -PAS-orange G procedure these cells stained blue-purple, demonstrating FSH/LH cells (blue or turquoise), ACTH/MSH cells (redpurple) and PRL cells (orange-red). The TSH cells were further differentiated from other functional cell types of the pars distalis on the basis of their typical cytological features, intraglandular distribution and by immunocytochemical double staining. In the pars distalis of adult male dogs the TSH cells were mostly shown to be smaller in size and less numerous than in bitches in the anestrous phase of the sexual cycle. Moreover, cytological alterations in the immunoreactive thyrotrophs in the pituitary of male and female dogs generally paralleled the spontaneous changes in thyroid function associated with thyroid atrophy and/or pituitary insufficiency, and thyroid hyperplasia or goiter. In conclusion, because of their specificity and high potency, the antisera to the β-subunits of bovine and rat TSH represent an effective tool for the selective immunocytochemical localization of TSH in the dog pituitary. This allows the study of the morphology and function of TSH cells under different physiological, pathological and experimental conditions.
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  • 22
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    Cell & tissue research 188 (1978), S. 99-106 
    ISSN: 1432-0878
    Keywords: LHRH-neurosecretion ; Avian hypothalamus ; Vasotocin neurosecretion ; Immunocytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A fluorescent technique applying specific LHRH and vasotocin antisera was used for the immunocytochemical localization of the respective neurosecretory systems in the hypothalamus of gonadectomized, testosteronetreated and/or serotonin injected male domestic ducks. An immunoreactive (IR) LHRH-producing system, with perikarya located in the preoptic nucleus, could be traced through the ventral hypothalamus down to the external layer of the rostral and caudal ME, in close vicinity to the hypophysial portal system. An IR-vasotocin system originating in the paraventricular and supraoptic nuclei ran through the ventral hypothalamus, but terminated in (i) the external layer of the rostral ME, and (ii) in the posterior lobe of the hypophysis.
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  • 23
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    Cell & tissue research 188 (1978), S. 119-132 
    ISSN: 1432-0878
    Keywords: Neurophysin ; Paraventricular nucleus ; Supraoptic nucleus ; Sheep ; Immunocytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary An antiserum cross-reactive against ovine neurophysins-I-II and -III has been used in conjunction with the immunoperoxidase histochemical procedure to localize the cells of the sheep paraventricular (PVN) and supraoptic nuclei (SON). In order to describe the topographical distribution of the SON and PVN a study was made on the serial sections cut (a) transversely from rostral to caudal positions and (b) sagittally from lateral to medial positions of the hypothalamus. The cells of the SON, when examined in the transverse aspect, extended approximately 1900 μ caudally and when examined in the sagittal plane were contained within a lateral-medial distance of 4830 μ. In each case the SON cells lay adjacent to the optic chiasm. As sections were cut transversely, the cells of the PVN first appeared in a rostral position defined as 0 μ and close to the ventral lining of the third ventricle. This general ventral and ventro-lateral distribution of cells maintained up to a caudal distance of approximately 840 μ. From positions 1260–2310 μ there was a dramatic dorsal shift of the PVN cells which by this time had also extended laterally. The total rostral-caudal distance occupied by the PVN cells was 3150 μ. That the lateral-medial distance occupied by the PVN was small (1050 μ) was determined on examining the magnocellular nuclei in sagittal section.
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  • 24
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    Cell & tissue research 188 (1978), S. 259-264 
    ISSN: 1432-0878
    Keywords: Hypothalamus ; Human fetus ; Oxytocin ; Neurophysin ; Immunocytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The use of antibodies against oxytocin or neurophysin enabled the detection by immunocytochemistry of oxytocin-neurophysin neurons in the hypothalamus in the human fetus. The perikarya of these neurons are located in the paraventricular and supraoptic nuclei. Immunoreactive neurons occur in the median eminence. The neurophysin immunoreactive neurons were more numerous than the oxytocin immunoreactive neurons. The specificity of the immunocytological reaction was controlled. The first oxytocin-neurophysin neurons are seen as early as the 14th week of gestation.
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  • 25
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    Cell & tissue research 186 (1978), S. 551-558 
    ISSN: 1432-0878
    Keywords: C-cells ; Thyroid gland ; Immunocytochemistry ; Calcitonin antibody ; Mammals
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the thyroid glands of the horse, pig, deer, mole, and rat, C-cells could be demonstrated by means of the immunocytochemical PAP-technique using rabbit antisera against human calcitonin. Only in ruminants, the crossreaction between the intracellularly stored antigen and the antibodies used appeared to be incomplete.
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  • 26
    ISSN: 1432-0878
    Keywords: Thyroid gland ; Immunocytochemistry ; Thyroglobulin ; Petromyzon marinus L
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Antibodies made against thyroglobulin (TG) were used in an immunocytochemical study for the light and electron microscopic localization of TG in the thyroid gland of the anadromous sea lamprey, Petromyzon marinus, during its upstream migration. TG was found in the follicular lumen and in some colloid droplets within the follicular cells. Except for an immunoreactive product observed in a small portion of the interstitial connective tissue, the location of TG in the lamprey was similar to that in the thyroid of the rat.
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  • 27
    ISSN: 1432-0878
    Keywords: Hypothalamus ; Dipnoi (Protopterus) ; Neurohypophysial hormones ; Immunocytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Using the unlabeled antibody peroxidase-antiperoxidase complex (PAP) technique at the light microscopic level, it has been shown that, in the dipnoan preoptico-hypophysial neurosecretory system, vasotocin and mesotocin are synthesized in separate neurons. In the preoptic nuclei, the perikarya of these two types of neurosecretory neurons are not located preferentially. The two types of neurosecretory perikarya give rise to separate vasotocinergic and mesotocinergic axons, respectively. The dipnoan median eminence and neural lobe contain separate vasotocinergic and mesotocinergic nerve fibres, the general distribution of which is described. In the pars distalis and the pars intermedia of the hypophysis, neurohypophysial hormone-containing nerve fibres have not been found.
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  • 28
    ISSN: 1432-0878
    Keywords: Cyproterone acetate ; d-Norgestrel ; Progesterone ; Pars distalis ; adenohypophysis ; Immunocytochemistry ; Dog (Beagle)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The effects of short-term (8 weeks) treatment with different doses of cyproterone acetate (CPA), d-norgestrel (d-N) and progesterone on cells of the pars distalis, as revealed by the immunoperoxidase technique, were studied in cycle-synchronized beagle bitches (first anoestrus). Pituitary glands from non-treated primiparous beagle bitches at the 6th and 9th week of pregnancy were also included. For immunochemical staining specific antisera to the following hormones were used: canine GH, canine PRL, porcine ACTH, bovine TSHβ, bovine LHβ and human FSHβ. Morphological features of high secretory activity in GH cells were evident even after the human oral contraceptive doses of CPA and d-N, and after a dose as low as 0.1 mg/kg/day subcutaneously (s.c.) of progesterone. In contrast, PRL cells did not show any significant treatment-related effects except in those animals which received the highest dose of d-N (0.5 mg/kg/day per os). In this group, as well as in all pregnant bitches, hyperplasia and hypertrophy of PRL cells were found. In the animals treated with the highest doses of CPA (4.0 mg/kg/day per os) and progesterone (42.5 mg/kg/day s.c.) as well as in pregnant bitches, ACTH/MSH and TSH cells showed marked atrophy and regressive changes. Similar morphological signs of depressed secretory activity were also observed in the cells shown to contain FSHβ and/or LHβ as a result of treatment with the highest dose of progesterone and at the 9th week of pregnancy. These structural responses indicate that quantitative and/or qualitative differences may exist between progesterone, the synthetic progesterone derivative CPA and the nortestosterone type progestagen d-N with regard to their effect on pituitary hormone secretion in the beagle bitch.
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  • 29
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    Cell & tissue research 194 (1978), S. 79-102 
    ISSN: 1432-0878
    Keywords: Duodenum ; Endocrine cells ; Differentiation ; Immunocytochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The development and cytodifferentiation of endocrine cells that produce the gastrointestinal hormones gastrin, cholecystokinin and secretin have been studied by a combined fluorescence-cytochemical, immunocytochemical and ultrastructural approach. The results show that, during development, several ultrastructurally distinct cell types exhibit COOH-terminal gastrin and cholecystokinin immunoreactivity. Furthermore, some cells simultaneously contain both gastrin- and cholecystokinin-specific antigenic determinants. Studies on the time course of development of gastrin and cholecystokinin cells, together with the above-mentioned data, suggest that gastrin cells may be converted into cholecystokinin cells in development. During this period, gastrin, cholecystokinin and secretin cells store the biogenic monoamine, 5-hydroxytryptamine a feature not displayed by the adult counter-parts of these cells. In the adult duodenum, characteristic enterochromaffin (EC) cells store 5-hydroxytryptamin for which, evidence for a possible hormonal role has been presented. Taken together, our data indicate that the differentiation of duodenal endocrine cells occurs in distinct steps, each involving a restriction in the biosynthetic repertoire of the cell.
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  • 30
    ISSN: 1432-0878
    Keywords: Pancreas ; Gut ; Pancreatic polypeptide (PP) cells ; Immunocytochemistry ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Pancreatic polypeptide (PP) cells in the pancreas and gut of chickens were studied by immunocytochemistry. In the pancreas PP cells were numerous and disseminated in the exocrine parenchyma. In this location they were first seen at the 9th day of incubation, i.e. several days after the appearance of glucagon, insulin and somatostatin cells. Very large numbers of these cells occurred from about the 14th day until shortly after hatching when the PP cell frequency was somewhat reduced. At the 17th day of incubation PP cells appeared in the duodenum. Subsequently the number of PP cells in the duodenum increased, and PP cells began to appear also in the jejunum-ileum (19th day) and in the proventriculus and colon (21st day). At hatching and a few days thereafter, PP cells were relatively numerous in the small intestines but much less frequent in the proventriculus and colon. One week after hatching PP cells had disappeared from the colon but remained in the proventriculus and small intestines. Ultrastructurally the PP cell was clearly distinguishable from the insulin, glucagon and somatostatin cells. It was characterized by the presence of spherical cytoplasmic granules which were membrane-bound and moderately electron dense. Areas of firm adhesion between PP cells and acinar cells in the form of desmosomes and possibly also gap junctions were observed.
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  • 31
    ISSN: 1432-0878
    Keywords: Pituitary gland ; Mexican axolotl ; Prolactin ; Somatotropin ; Immunocytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The indirect immunofluorescence procedure was used to identify prolactin (LTH)-and somatotropin (STH)-producing cells in the pituitary of the Mexican axolotl. Histological staining techniques were employed to corroborate immunocytological results. The LTH cells are large, orange-staining cells (acidophils 1) distributed in the posterior two-thirds of the pars distalis. The STH cells are small, erythrosinophilic elements (acidophils 2) principally concentrated in the dorsal part of the pars distalis.
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  • 32
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    Cell & tissue research 190 (1978), S. 151-161 
    ISSN: 1432-0878
    Keywords: Pituitary gland ; Rhesus monkey ; Immunocytochemistry ; Luteinizing hormone ; Thyroid stimulating hormone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Pituitary glands from juvenile (pre-pubertal) and adult male and female rhesus monkeys were examined following immunocytochemical staining with antisera to the beta subunits of ovine luteinizing hormone (LHβ) and of human thyroid stimulating hormone (TSHβ). The LHβ antiserum reacts with a cell that is PAS-positive, occurs singly and is randomly distributed throughout the pars distalis. The diameter of these cells is approximately 11.5 μm. They do not seem to vary in number in either juveniles (pre-pubertals) or adults, or in males or females. There appears to be fewer LH cells in the pituitary glands of pregnant and lactating females. In addition to staining cells in the pars distalis, the antiserum also reacts with a population of cells located in the pars tuberalis. The cells that stain with the anti-TSHβ serum are confined primarily to the pars distalis. They are approximately 15.8 μm in diameter and are generally found in groups or clusters located in the anterior and medial regions of the gland. The TSH cells vary in number from one animal to another; however, this variability is unrelated to the age or the sex of the animals. No demonstrable changes occur in the number of TSH cells during pregnancy or lactation.
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  • 33
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    Cell & tissue research 193 (1978), S. 211-218 
    ISSN: 1432-0878
    Keywords: 17β-estradiol ; Pituitary gland ; Dog (Beagle) ; Immunocytochemistry ; Glycoprotein hormones (FSH, LH, TSH)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The effect of long-term treatment (52 weeks) with high doses of 17β-estradiol (1.28 mg/kg/week intramuscularly) on gonadotrophs was studied in the pituitary gland of the beagle bitch. For immunochemical staining the immunoperoxidase technique and antisera to the specific beta (β) subunits of FSH and LH were employed. For control purposes antisera to the following hormones were also used: bovine TSHβ, canine GH, canine PRL and porcine ACTH1. In the pars distalis and pars tuberalis of control bitches, in addition to the cells which react solely with antisera to either LHβ or FSHβ, most cells were reactive to both antisera. The cells stained for FSHβ were less numerous than those shown to contain LHβ. TSHβ, PRL, GH and ACTH/MSH were localized in distinctly different cell types in the pars distalis of all control animals. In the treated bitches, almost complete regression of cells classically identified as gonadotrophs and stained for LHβ was observed. On the other hand, using the antiserum to FSHβ, selective immunochemical staining was localized in cells fitting the morphological characteristics of TSH cells. All these cells were also stained for TSHβ. However, a few cells were also shown to react solely with the antiserum to TSHβ. These cells, which seem to contain both TSHβ and FSHβ, were further clearly differentiated from PRL, GH and ACTH/MSH cells on the basis of their cytological features, intraglandular distribution and by immunochemical double staining. These observations support the concept that the one cell-one hormone theory may not necessarily apply to the glycoprotein hormones of the dog pituitary gland.
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  • 34
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    Cell & tissue research 194 (1978), S. 327-336 
    ISSN: 1432-0878
    Keywords: Prolactin ; Growth hormone ; Ovine pituitary ; Immunocytochemistry ; Granule size
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Using the peroxidase-antiperoxidase immunocytochemical staining technique, prolactin and growth hormone cells have been identified and described in the ovine pituitary. The image analysing computer, Quantimet 720, was used to assess accurately the size range of the secretory granules in these cell types. The area size distributions of the prolactin and growth hormone granules are similar. An increased proportion of larger granules was observed in the prolactin cells post-partum. Serial sections stained alternately for prolactin or growth hormone confirmed that the cells contain either prolactin or growth hormone but not both.
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  • 35
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    Cell & tissue research 195 (1978), S. 183-187 
    ISSN: 1432-0878
    Keywords: Somatostatin-containing neurons ; Hypothalamus ; Median eminence ; Immunocytochemistry ; Domestic mallard
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the hypothalamus of the adult domestic mallard, small to medium-sized perikarya are stained specifically with rabbit antiserum against cyclic somatostatin (PAP technique of Sternberger). The somatostatin-immunoreactive material is located in neurons different from those containing immunoreactive LHRH, vasotocin or mesotocin. Somatostatin-containing perikarya are observed 1) in a chain-like arrangement extending from the area of the median division of the supraoptic nucleus to the caudal end of the paraventricular nucleus; 2) as single cells in the preoptic region; and 3) as a conspicuous formation in the optic tract division of the supraoptic nucleus. In the rostral portion of the median eminence, somatostatin-immunoreactive axons penetrate into the external zone. Fine accessory fiber bundles project to the neural lobe.
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  • 36
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    Cell & tissue research 186 (1978), S. 393-398 
    ISSN: 1432-0878
    Keywords: β-Lipotropin ; Hypothalamus ; Hypophysial portal capillaries ; Immunocytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary β-Lipotropin (β-LPH) has been localized in hypothalamus and pituitary of sheep and ox by the immunoperoxidase technique. In both species β-LPH was found in perikarya of arcuate neurons as well as in cells of the anterior and intermediate lobes of the pituitary. A large number of immunoreactive axons were found in the arcuate region; some appeared to innervate other neurons and others projected to portal capillaries. Stained fiber segments were also scattered throughout the hypothalamus. The presence of β-LPH in hypothalamic neurons supports the possibility that brain β-LPH may be a precursor for opiate-like or other peptides which may be involved in neuromodulation or neurohormonal activities.
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