bluuebunny/crossref_metadata_2025 huggingface dataset:
Laser evaporation of some solid organosilicon polymers
Authors: Pola J , Vitek J , Polyakov Yu P , Guselnikov L E , Matveychev P M , Bashkirova S A , Tläskal J , Mayer R
Published: December 2004

Continuous wave (cw) CO2 laser irradiation of some organosilicon polymers composed of ‐Me2Si‐, ‐Me2SiMe2SiCH2‐, RMeSi‐ and RMeSiMe2SiCH2CH2‐ units (where R = methyl, adamantyl, phenyl and hydrogen) leads to the evaporation of the polymer and is dominated by the formation of a solid deposit that has a continuous structure. It is assumed that chemical changes occur prior to the transfer of ejected material to the gas phase and that these consist mainly of the formation of high molecular biradicals or 1,2‐disilacyclobutane monomer that both re‐polymerize spontaneously upon their deposition onto a nearby cold surface. The mechanism of these specific decompositions of the polymers is assessed on the basis of the IR spectra of the deposits and, for the minor gaseous products, identification by GC MS techniques.
Analytical methods for airborne arsine, silane and dichlorosilane by adsorption sampling and AA spectrophotometry
Authors: Matsumura Yoshimi , Ono‐Ogasawara Mariko , Furuse Mitsuya
Published: December 2004

Analytical methods for arsine, silane and dichlorosilane by adsorption sampling and elemental analysis with graphite furnace AA were studied to establish convenient methods for atmospheric contamination surveys. This study included the following five items: (1) primary selection of adsorbents applicable to adsorption sampling; (2) examination of the adsorption capacities of the adsorbents for the gases; (3) improvement of the adsorbents by chemical modification; (4) desorption of the gases adsorbed on the adsorbents with solvents; and (5) quantitative analysis of arsenic and silicon in the solutions.

Experimental results showed that active carbon made from synthetic thermosetting resin beads contained no aresenic and little silicon as impurities. This active carbon by itself was proved to adsorb arsine and dichlorosilane, but not silane. Impregnation with sodium hydroxide of the active carbon improved the adsorption capacity for all three gases. Refined silica gel, free from arsenic contamination, did not adsorb arsine by itself but potassium permanganate impregnation produced an adsorption capacity for arsine.

The adsorbed arsine on the active carbon was desorbed into a hot dilute nitric acid solution with high efficiency (over 90%), but arsine adsorbed on sodium hydroxide impregnated active carbon or on potassium permanganate impregnated silica gel was dissolved into various solutions only at lower efficiencies. Silane adsorbed on sodium hydroxide‐impregnated active carbon was desorbed with hot water with an efficiency higher than 90%. Dichlorosilane adsorbed on the active carbon with or without sodium hydroxide impregnation was desorbed with a nitric acid solution with efficiency of 85%. The lower determination limit for arsine able to discriminate from background interference of arsenie was 0.005 ppm, and those for silane and dichlorosilane were each 0.05 ppm for 3‐dm3 air samples.
Silicone curing and polyurethane preparation promoted by latent organotin catalysts
Authors: Jousseaume B , Gouron V , Pereyre M , Francès J‐M
Published: December 2004

The use of new latent organotin cataylsts has been investigated for silicone curing and polyurethane preparation. These functional tetraorganotins are inactive at room temperature and liberate in situ the active species, diorganotin dicarboxylates, when heated. They confer long pot‐lives to the mixtures in which they are incorporated. Upon heating, these mixtures are rapidly cured or polymerized after a short activation period.
Photochemistry of iron pentacarbonyl adsorbed on titanium dioxide
Authors: Ukisu Yuji , Sato Shinri , Ohmori Tadayoshi
Published: December 2004

The photolysis of iron carbonyl (Fe(CO)5) adsorbed on titanium dioxide (TiO2, anatase) was studied by FT‐IR spectroscopy. When adsorbed Fe(CO)5 is illuminated by visible and near‐UV light, the IR spectrum of its photolysis products is hardly observed, indicating that most of the Fe(CO)5 is photodecomposed to iron(0) or iron oxides on TiO2. The carbon monoxide (CO) evolution rate upon illumination depends on the wavelength of light; 433 nm light is more effective for CO evolution than 366 nm light. This result implies that the band‐gap excitation of TiO2 has little effect on the photolysis of adsorbed Fe(CO)5, since the absorption edge of TiO2 (anatase) lies at around 400 nm. The effects of substrates on the photolysis of adsorbed Fe(CO)5 are discussed with reference to previous results obtained for aluminium oxide (Al2O3) and silicon dioxide (SiO2), on which the photolysis leads to the formation of Fe2(CO)9 or Fe3(CO)12.
Synthesis and spectroscopic characterization of organotin derivatives of N‐benzoylglycylglycine
Authors: Ruisi Giuseppe , Giudice Maria Teresa Lo
Published: December 2004

Di‐ and tri‐organotin derivatives of N‐benzoylglycylglycine (HBzGlyGly) were synthesized and characterized by infrared, 1H, 13C NMR and 119Sn Mössbauer spectroscopy. Diorganotin derivatives appear to be dimer distannoxanes ([R2SnBzGlyGly]2O)2 (R = CH3, n‐C4H9, n‐C8H17) with a ladder‐type structure where tin atoms are five‐coordinated and N‐benzoylglycylglycine alternatively acts as a unidentate or bridging bidentate ligand through the carboxylate group. For triorganotin derivatives R3SnBzGlyGly (R= CH3, n‐C4Hg) we propose a polymeric structure where N‐benzoylglycylglycine bridges planar SnC3 units through the carboxylate group.
Speciation of butyltins in fish and sediment by means of gas chromatography with flame photometric detection
Authors: Martin‐Landa Isabel , Pablos Fernando , Marr Lain L
Published: December 2004

A modified method for the determination of tributyl‐, dibutyl‐, and monobutyl‐tin in fish and sediment samples is proposed. The samples are digested with hydrochloric acid and the butyltin compounds are extracted into a tropolone solution in pentane and pentylated by a Grignard reaction. The products are cleaned up by washing with a sodium hyrdoxide solution, dried over sodium sulphate, concentrated by evaporation and analysed by gas chromatography with flame photometric detection, using an interence filter at 610 nm. Problems peculiar to the fish and sediment samples are overcome by this improved clean‐up procedure. The limit of detection for tributyltin in fish is 0.04 m̈g g−1 and the reproducibility at 0.06 μg g−1, expressed as the relative standard deviation, is 6.8%. Contaminated sediment samples were found to contain the mixed methylbutyl‐tin compounds Me2BuSn+ and MeBu2Sn+.
Synthesis of triphenyl‐phosphine, ‐arsine and ‐stibine derivatives of phenylmethinyltricobalt enneacarbonyls and their catalytic properties
Authors: Wang Yun‐Pu , Lei Zi‐Qiang , Feng Han‐Yu , Liu Yong‐Hong
Published: December 2004

Mono‐substituted triphenyl‐phosphine, ‐arsine and ‐stibine derivatives of phenylmethinyltricobalt enneacarbonyls PhCCo3(CO)8L (where L  PPh3, AsPh3 and SbPh3) were synthesized. The Co(2p3/2) binding energy (Eb) was lowered from 781.3 eV in PhCCo3(CO)9, to 780.0 eV in PhCCo3(CO)8PPh3, to 780.3 eV in PhCCo3(CO)8AsPh3 and to 780.5 eV in PhCCO3(CO)8SbPh3. Hydroformylation selectivity to total aldehyde and alcohol of the substituted clusters PhCCo3(CO)8L was about 100%, but that of the parent cluster PhCCo3(CO)9 was 93.8%. Hydroformylation products of styrene and di‐isobutene were the completely normal aldehyde when using PhCCo3(CO)8AsPh3 as catalyst.
Tetraethylammonium (diorgano)halogeno‐(2, 6‐pyridinedicarboxylato)stannates: Synthesis, characterization and in vitro antitumour activity
Authors: Willem Rudolph , Biesemans Monique , Bouâlam Mohammed , Delmotte Ann , Khloufi Abdelaziz El , Gielen Marcel
Published: December 2004

The synthesis and characterization of tetraethylammonium (diorgano)halogeno(2, 6‐pyridinedicarboxylato)stannates are described. The solution structures of these complexes in CDCl3 and DMSO are discussed on the basis of 119Sn and 19F NMR data. Their in vitro antitumour activities against two human tumour cell lines, MCF‐7 and WiDr, are presented.
The biotransformation of monomethylarsonate and dimethylarsinate into arsenobetaine in seawater and mussels
Authors: Cullen W R , Nelson J C
Published: December 2004

Water‐soluble 3H‐labeled arsenic compounds were phenol‐extracted from mussels (Mytilus edulis) and seawater after exposure to [3H]monomethylarsonate (MMAA) and [3H]dimethylarsinate (DMAA). Varying amounts of [3H] arsenobetaine were found in mussels and seawater, depending upon the experimental conditions. The results indicate that arsenobetaine is principally biosynthesized by microscopic organisms in the seawater and that it is bioaccumulated by mussels. Total arsenic concentrations in mussel flesh, byssal threads and shells were also determined, showing concentration increases in all three compartments.
Development of the infundibulum of jungle fowl during incubation indicating neurohaemal role for this area
Authors: Graber Jean W. , Nalbandov A. V.
Published: December 2004

An area under the ependyma of the infundibulum in jungle fowl hens enlarges progressively during incubation. The structure is reduced in size and altered in appearance in laying hens, regressed in nonlaying hens, and absent in males. Enlargement of the structure does not depend on increasing or decreasing day length. The area did not enlarge in jungle fowl receiving injections of prolactin. No similar structure was found in incubating house sparrows, rock doves, or ring‐necked pheasant.

Histological and histochemical examination of the enlarged area led to the tentative conclusion that it may represent a neurohaemal depot for ergones from the infundibular hypothalamic nuclei and may be evolved from a structure homologous with the neurohypophysis of lower vertebrates.
Synaptic patterns of the superficial layers of the superior colliculus of the rat
Authors: Lund Raymond D.
Published: December 2004

An electron microscopic study has been undertaken of the upper layers of the superior colliculus, into which run fibers from the retina and visual cortex. Study of the normal synaptic patterns shows large numbers of serial synapses, particularly near the surface of the colliculus. The presynaptic components usually contain round vesicles and the intermediate profiles always contain flattened vesicles. The latter may be dendrites, dendrite‐like or dilatations of such profiles. Degeneration studies indicate that optic terminals are especially dense near the surface and that they are often the presynaptic terminal of a serial synapse. Very few optic terminals occur in the stratum opticum. Cortical afferents from the visual area mostly end deep in the stratum griseum superficiale, and in superficial stratum opticum, usually on small clear profiles.

Studies of the progress of degeneration indicate that optic terminals first show a predominantly neurofilamentous and associated glycogen reaction, and later a predominantly electron dense reaction. Cortical terminals show an initial dense reaction, with occasional neurofilamentous endings. These time course fit well with light microscope data from Nauta and Glees stained material.

The synaptic patterns described here closely resemble patterns described in retina and dorsal lateral geniculate body. How these reflect functional similarities has yet to be resolved.
Observations on the postnatal development of clarke's column in the kitten
Authors: Smith Diane Elizabeth
Published: December 2004

Studies on the postnatal development of Clarke's column were undertaken in order to ascertain if there were changes observed morphologically that would be compatible with the results so far reported both anatomically and physiologically on the afferent supply and the cerebellar end‐point of this system. The studies were carried out on the L.2 and L.3 segments of the spinal cord of kittens ranging in age from newborn to eight weeks. The principal staining methods employed were the Ha modification of the Golgi‐Cox, the Rasmussen technique for synapses, and Bodian's fiber stain. The sections were viewed using substage and reflected illumination.

The most pertinent findings involved (1) the number of synapses and their distribution over the cell body and dendrites and (2) the number of stem dendrites and their orientation. There is an apparent lack of stainable synapses at birth, by eight days synaptic endings are present and by three weeks the entire cell is encrusted with two distinct types of synaptic end bulbs. Regarding the second point, a noticeable decrease was seen in the number of stem dendrites with a concomitant centripetal orientation of the dendritic tree in relation to the center of Clarke's column. The significance of these changes on the maturation of Clarke's column, on its afferent input and on the development of the dorsal spinocerebellar tract as a functional system is discussed.
Ventricular system of the brain of the dolphin, Tursiops truncatus, with comparative anatomical observations and relations to brain specializations
Authors: McFarland W. L. , Morgane P. J. , Jacobs M. S.
Published: December 2004

A comparative and quantitative anatomical study of the cerebral ventricular system of the dolphin, Tursiops truncatus, and six other mammalian species, including man, has been made in the course of extensive neuroanatomical investigations of the dolphin. Several techniques have been used in these studies to confirm the morphological arrangement and contours of the ventricles. Casts of the ventricles were produced by use of a variety of casting media and methods and their relative merits were investigated and described. Following injection of the brain with casting media, the brain was either totally removed by dissection or digestion or one hemisphere dissected away to reveal the relationships of the ventricular cast to the opposite cerebral hemisphere. Serial sections of the brains of three dolphins were cut in three cardinal planes, and from these a model of the entire ventricular system was reconstructed. Serial sections (Nissl and Loyez) were also used to identify structures closely related to the ventricular cavities. Our results show that components of the cerebral ventricular system of the dolphin reflect, to a considerable degree, many of the specialized features of that brain including brachycephaly, widened and foreshortened temporal lobes, large limbic lobe, hypodeveloped frontal region, absence of an occipital pole, and massive development of the tectal acoustic apparatus. The morphological characteristics of the ventricular system and the relationship of this system to brain areas is discussed with respect to possible functional and phylogenetic implications.
Nerve endings in the urinary bladder of the cat
Authors: Fletcher Thomas F. , Hammer Robert F. , Bradley William E.
Published: December 2004

Urinary bladders from mature cats, fixed in various degrees of distension, were studied with silver staining techniques under the light microscope, and with the electron microscope. Ganglia were located primarily in the adventitia, although small collections of perikarvons were located in nerves within the muscle coat. Large nerve trunks enclosed in perineural epithelium penetrated from the adventitia into the muscle coat, giving rise to smaller nerves which ran in the space between muscle fascicles. Small nerves entered each muscle fascicle, giving rise to final branches characterized by extreme tortuosity. There was less kinking and coiling of nerve fibers in bladders fixed in a more distended state. Encapsulated endings and myelinated fibers were scarce.

Within a muscle fascicle, nerves were scant. Terminal branches intertwined among the individual smooth muscle cells as free nerve endings. Terminal axons continued to be ensheathed by Schwann cells. Neuromuscular synapses were characterizd by retraction of the Schwann cell from one side of the axon, presence of synaptic vesicles, and synaptic gaps of 400–600 Å. Areas of close contact between flattened and interdigitating parts of adjacent smooth muscle cells were common. Membrane complexes of pinocytotic vesicles and endoplasmic reticulum were distributed around the periphery of individual smooth muscle cells. Smooth muscles cells appeared to vary in the density of their myofilament content.
Projections from the orbital gyrus in the cat. II. To telencephalic and diencephalic structures
Authors: Mizuno Noboru , Clemente Carmine D. , Sauerland Eberhardt K.
Published: December 2004

Direct projections from the anterior part of the orbital gyrus and its immediate vicinity to telencephalic and diencephalic structures in the cat were investigated by means of the Nauta and Marchi methods.

Association fibers were observed to project to the ipsilateral coronal gyrus, the anterior part of the insular cortex, and the lateral part of the pericruciate gyrus. Degenerated fibers originating at the site of the lesion were traced to the callosal body, and from there chiefly to the contralateral putamen and the contralateral orbital and coronal gyri. Projection fibers to the telencephalic nuclei were found to terminate in the head of the caudate nucleus, the putamen, claustrum, and anterior amygdaloid area. Degenerated fibers in the external capsule were traced to the prepyriform area and the lateral part of the olfactory tubercle. Some of these components were observed to join the medial forebrain bundle and could be followed to the lateral preoptic area. Orbitothalamic fibers were traced through the anterior limb of the internal capsule and the internal medullary lamina. These fibers were found to terminate in the rostroventral part of the nucleus reticularis and ventralis anterior, and in the rostral parts of the intralaminal nuclei.
Structural characteristics of cell and fiber populations in the optic tectum of the frog (Rana catesbeiana)
Authors: Potter H. D.
Published: December 2004

In the optic tectum Cajal's method II for neurofibrils reveals two major fiber systems in which the fibers are oriented perpendicular to one another. The outer fiber system, composed of seven laminae, lies in the superficial zone with its fibers oriented in the anteroventral to posterodorsal direction; Golgi preparations show that optic tract fibers enter the outer system laminae at the tectal margin, run within single laminae, and end in arborizations that are elongated in the dominant fiber direction. The intermediate fiber system is composed of bundles of fibers in lamina 7 of Ramón and the superficial zone; its fibers are oriented in the anterodorsal to posteroventral direction. A third deep fiber system, forms fibrous laminae in the region between lamina 7 and the ependyma.

In Golgi impregnations the deep cells are of two major classes: pyramidal cells with relatively narrow dendritic arbors in the superficial zone and candelabra cells with broad arbors. Many pyamidal cell dendrites have lamellar branching patterns such that terminal bushes occur within one or another of the outer system laminae. The multipolar cells within lamina 6 and lamina 7 of Ramón send large, unbranched axons directly into the deep medullary lamina and appear to be the major efferent neurons. Near the pia the perikarya of superficial granule cells give rise to single processes that branch repeatedly within the superficial zone.
Observations on the morphology of a nucleus in the dorsolateral funiculus of the spinal cord of the guinea‐pig, rabbit, ferret and cat
Authors: Gwyn D. G. , Waldron H. A.
Published: December 2004

A nucleus was found in the dorsolateral funiculus of the spinal cord of the guinea‐pig. The nucleus extended from upper cervical to lumbar segments of the cord and was similar in appearance to that previously described in the rat. The nucleus also extended into lumbar segments of the spinal cord in both the rabbit and the ferret although in these species there were not as many cells in the nucleus in thoracic and lumbar segments of the cord as in the guinea‐pig. In the cat, the nucleus was confined to the upper two or three cervical segments of the spinal cord.
Ultrastructural differentiation of the junctional complex of the avian choroidal epithelium
Authors: Doolin Paul F. , Birge Wesley J.
Published: December 2004

The junctional complex of the choroidal epithelium of the adult domestic fowl consists of three characteristic components—the zonula occludens, zonula adherens and macula adherens. The quintuple‐layered zonula occludens (tight junction) occupies a juxtaluminal position and extends in depth from 0.2–0.4 μ. As a consequence of the intimate fusion of the outer leaflets of the apposed cell membranes, the tight junction is void of any discernible intercellular space. The zonula adherens normally varies in depth from 0.35–0.55 μ. Moderate to heavy accumulations of fibrillar and granular cytoplasmic material occur adjacent to the inner leaflets of the apposed cell membranes. These dense, cytoplasmic bands mesh with fibrillar elements of the general cytoplasm. The intercellular space of the intermediate junction is frequently attenuated by constrictions in the cell membranes. The tight and intermediate junctions appear to form continuous belts encircling each epithelial cell. The macula adherens (desmosome) is not especially well developed, usually lacking well developed cytoplasmic plaques.

The early development of the zonula occludens is marked by the convergence of the apposed cell membranes, starting first at a localized point at or near the basal margin of the presumptive tight junction. Subsequently, convergence occurs at one or a few additional points, often near the middle of the developing tight junction. Finally, preparatory to membrane fusion, the adjacent cell membranes are brought into close apposition throughout the linear extent of the tight junction. Membrane fusion usually commences at or near the lower margin of the zonula occludens, in the area of initial membrane convergence, and then proceeds toward the luminal border.

With the onset of membrane convergence, a network of fine fibrillar and granular cytoplasmic material accumulates adjacent to the inner leaflets of the apposed cell membranes. This cytoplasmic development subsides in the tight junction subsequent to membrane fusion but persists in moderate to dense accumulations in the other areas of the junctional complex. Numerous other associated events occurring during the differentiation of the junctional complex are discussed in detail.
Autoradiographic and histological studies of postnatal neurogenesis. III. Dating the time of production and onset of differentiation of cerebellar microneurons in rats
Authors: Altman Joseph
Published: December 2004

In one experiment rats were injected with single does of thymidine‐H3 at 6 hours, 2, 6 and 13 days of age, or with multiple doses during two periods of early life, and were killed when 2, 4 and 6 months old. In the autoradiographic analysis attention was focused on the time of origin and differentiation of basket, stellate and granule cells in different regions of the cerebellar cortex. In another, non‐radioactive study, in rats ranging in age from newborn to adult, the development of the cerebellum was studied with quantitative and qualitative histological techniques.

In the sagittal plane the area of the cerebellum increases over 20‐fold from birth to 21 days. This increase is primarily due to the growth of the cerebellar cortex, much of the increment in the area of the subcortical regions occurring after 21 days. During the first week the growth of the different layers, excepting the proliferative external granular layer, is sluggish. During this period, the cells of the external granular layer do not differentiate but provide stem cells to this growing proliferative matrix. These proliferating and migrating cells of the external granular layer are the precursors of the basket, stellate and granule cells of the cortex; glia cells probably arise from cells multiplying locally. The first cells to differentiate are situated in the lower half of the molecular layer and include basket cells. Stellate cells differentiate later, with a peak at the end of the second week. The bulk of granule cells differentiate during the second and third weeks, with 25–80% of them, depending on the region, being formed between 11–21 days. These differences, together with several histological criteria (thickness of external granular and molecular layers, appearance of Purkinje cells) were used for constructing regional developmental maps of the cerebellar cortex. Granule cells differentiate in the depth of vermian fissures before they do over the exposed surfaces of the lobes; the ventral lobes (lingula and nodulus) mature before the anterior lobes; and the last maturing vermian lobes are the tuber, declive and culmen. The hemispheres, with some exceptions, mature later than the vermis, with the paraflocculus being among the last maturing structures.
Encapsulated nerve end‐organs in the rabbit, mouse, sheep and man
Authors: Straile William E.
Published: December 2004

There is a system of highly specialized blood vessels around each sensory hair follicle in the rabbit. The system includes two arteriovenous shunts and a cylinder of dilative blood vessels enclosed in a large bulbous capsule of connective tissue. The shunts, dilative blood vessels and capsule surround two cylinders of nerve fibers; together these structures constitute the largest neurovascular end‐organ in skin. The end‐organ is similar to the glomus‐Pacinian corpuscle complex in the hairless digital skin of man.

The blood vessel cylinder and arteriovenous shunts in rabbit skin connect with a system of dilative blood vessels that are enclosed in another capsule of connective tissue under a small thick pad of sensory epidermis, beihnd the sensory hair follicle. The pad of epidermis contains expanded nerve fibers (Merkel's discs) that end near a cluster of Merkel (tactile) cells. In some regions of skin, each area of sensory epidermis is associated with the orifice of a sweat gland duct.

In hairy skin of the rabbit, mouse and sheep, the areas of sensory epidermis, Merkel cells and Merkel's discs are distributed in parallel chains or in whorls and loops. Similarly, in the hairless skin of man the sensory epidermis, clusters of Merkel's discs and sweat duct orifices are distributed together in rows, whorls and loops that form the finger and palmer prints. In some regions of hairy human skin the same components occur together in small circular whorls called theHaarscheibenorRosetten.
Secondary olfactory projections in the galago (Galago crassicaudatus) and the tree shrew (tupaia glis)
Authors: Ferrer Nathaniel G.
Published: December 2004

The efferent projection fibers from the olfactory bulb have been studied using the Nauta‐Gygax and the Fink‐Heimer methods for degenerating axons after lesions were suitably placed by thermo‐coagulation. From the olfactory bulb efferent fibers by way of the ipsilateral lateral olfactory tract end as preterminal and terminal fibers in the lateral, the external and the ventral segments of the anterior olfactory nucleus; the lateral two‐thirds of the lateral olfactory tract, the cortical and the medial nuclei of the amygdaloid complex.
Dark profiles in the apparently‐normal central nervous system: A problem in the electron microscopic identification of early anterograde axonal degeneration
Authors: Cohen Elsa B. , Pappas George D.
Published: December 2004

Tissue taken from the ventrobasal thalamic nucleus of normal adult cats and examined in the electron microscope contained electron‐dense profiles which were morphologically indistinguishable from those seen in tissue from the same area of cats with dorsal column nucleus lesions of two and four days'duration. The number of dense profiles seen in some sections from normal material was greater than the number seen in any of the sections from lesioned material. It is proposed that such dense profiles may represent portions of the “dark” cells of light microscopy. Increased electron density is currently used as the major criterion in electron microscopy for recognizing certain types of experimentally‐induced anterograde axonal degeneration in the central nervous system. It is suggested, on the basis of the data presented here, that a careful review may be necessary of the validity of this criterion.
Hypothalamo‐hypophyseal system in the minnow, Phoxinus phoxinus L. with a note on the effects of hypophysectomy
Authors: Bhargava H. N.
Published: December 2004

The developmental differentiation of the hypothalamo‐hypophyseal system and its disposition in the adult normal minnow is described. Neurosecretory stainable material is present either as granules or droplets in the nucleus preopticus and it is suggested that they are related with one another and follow a sequence in their developmental appearance. This differentiation of the neuorsecretory material and its distribution along the preoptico‐hypophyseal tract suggests a strong basis in support of the “transport‐hypothesis” of Bargmann and Scharrer ('51). The presences of the Herring bodies and peripheral movement of the neurosecretory material along the axon is suggestive of the functional role performed by the tract in the process of storage and release of hormone into the circulation.

The presence of intrathalamic branches of the optic nerve and their close association with neurosecretory fibers of the tract seem to be of significance in the important problem of retina‐pituitary relationship.

Injections of synthetic oxytocin, synthetic lysine vasopressin and a suspension of acetone‐dried hypothalmus containing nucleus preopticus and the neurosecretory material have no effect on the color response in the minnow.

The effect of hypophysectomy clearly confirms that the axons of the nucleus preopticus pass down to the neurohypophysis. After severe operational interruptions of the fibers, their trophic centers (the cell bodies of the nucleus preopticus) degenerate. The accumulation of the neurosecretory material in the stalk region after hypophysectomy supports the “transport‐hypothesis.”
Electron microscopic study on gliosome formation in postnatal development of spinal cord in the cat
Authors: Hashimoto Paulo H.
Published: December 2004

The CNS of cats including newly‐born, 2 day‐, 4 day‐, 10 day‐, 18 day‐, 3 week‐, 6 week‐ and 3 month‐old kittens and adults, were fixed by perfusion from the aorta with 1% osmium tetroxide in acetate‐veronal buffer, or with 2.5 to 3% glutaraldehyde or 4% formaldehyde in phosphate buffer and retreatment with osmium tetroxide after removal. The astrocytes in the intermediolateral horn of the thoracic spinal cord and in the neighboring lateral funiculus were examined under the electron microscope. The astrocytic mitochondria are larger than the neuronal ones at birth. They have a finely granular matrix and dispersed cristae mitochondriales. During the first 4 to 10 days after birth many of the astrocytic mitochondria enlarge, with an increase in the amount of matrix material and its crystallization into a filamentous array, forming “gliosomes.” Within two to three weeks, a bundle of crystalline filaments with a regular periodicity are formed in the matrix. The rough surfaced endoplasmic reticulum seems to be closely associated with the processes of gliosome formation. Namely, cisterane of the rough endoplasmic reticulum first accompany the growing mitochondria, then lose ribosomes on their proximal membranes, and finally change into vesicles of the smooth endoplasmic reticulum around the gliosomes and gliofilaments. The possible significance of these structural changes is discussed.
The cortical projection of the pulvinar in the cat
Authors: de. V. Clüver P. F. , Campos‐Ortega J. A.
Published: December 2004

The cortical projection from the pulvinar has been studied in the cat with the help of stereotaxic coagulation and silver impregnation methods. The pulvinar of the cat projects fundamentally into the gyri suprasylvius posterior and medius, lateral bank of the posterior lateral sulcus, middle ectosylvian and anterior sylvian gyri. The projection to the gyrus suprasylvius is topologically organized overlapping with the projection of the n. lateralis posterior. The question of the ending of degenerated fibers in the parasplenial gyri is discussed.

The thalamic degenerated fibers are present in the deeper layers of the cortex. There are however regions in the posterior suprasylvian gyrus in which degenerated fibers are present in the molecular layer as well as in the deeper layers. This different topographic distribution of the endings of the thalamic fibers is discussed with relation to the problem of the “sustaining” and “essential” thalamo‐cortical projections.
Spinal cord representation of the micturition reflex
Authors: Oliver John E. , Bradley William E. , Fletcher Thomas F.
Published: December 2004

The spinal cord origin and peripheral pathways of the sensory and motor nerves to the urinary bladder were delineated in the cat by stimulating the appropriate nerves near the urinary bladder and recording from the dorsal and ventral rootlets near the spinal cord.

The parasympathetic preganglionic neurons originated in the sacral segments of the spinal cord and reached the bladder by way of the pelvic nerve. The preganglionic parasympathetic perikarya to the urinary bladder were distributed over a length of approximately 1.5 segments, centered near the junction of segments S‐2 and S‐3 in cats with a median arrangement of the lumbosacral plexus. Conduction velocities in preganglionic parasympathetic fibers to the bladder ranged from 46 to 2 M/sec with a mean maximal velocity of 18.2 M/sec.

The major sympathetic pathway to the bladder was in the hypogastric nerve. Preganglionic sympathetic fibers originated in the lumbar spinal cord and traveled through the caudal mesenteric ganglion and hypogastric nerve to the urinary bladder. There were both ipsilateral and contralateral preganglionic and afferent fibers in this pathway. The preganglionic sympathetic neurons originated in segments L‐2 and L‐5. They were usually distributed over approximately 2 full segments centered near the junction of L‐3 and L‐4 in cats with a median arrangement of the lumbosacral plexus.

Neurons involved in the micturition reflex may extend from the rostral end of the L‐2 segment to the caudal end of the S‐3 segment. The sympathetic preganglionic neurons were usually separated from the somatic and parasympathetic columns by segments L‐5 to L‐7.
On the direct cortical connections of the nucleus centrum medianum thalami
Authors: Totibadze Nana K. , Moniava E. S.
Published: December 2004

The center median nucleus of the cat was damaged electrolytically by a horizontally introduced electrode through the cerebellum. After a postoperative survival of ten days to a month degenerated fibers were studied by a modified Nauta method. Direct connections of the center median nucleus of diffuse character were found terminating bilaterally in V–VI layers of the neocortex. Another cortical projection from the center median nucleus terminating in layers III–IV was limited to the anterior and middle regions of the lateral and suprasylvian gyri, the anterior ectosylvian and sylvian gyri and the cornal gyrus. Fibers to the contralateral cortex were found to pass through the corpus callosum.

Threshold stimulation of the center median nucleus evoked recruiting response (with a short latency) only in the limited area of the cortex whose direct connections terminate in III–IV layers. Diffuse recruiting response was obtained only with the stronger stimulation. Following lesion of the center median nucleus, diffuse recruiting response, evoked by stimulation of other nonspecific nuclei, was not obtained in the area of the cortex whose III–IV layers recieve connections from the center median nucleus. This supports the view that diffuse recruiting response during stimulation of one nonspecific nucleus is evoked by intrathalamic sprading of impulses to other nonspecific nuclei.
Localization of sound after section of the brachium of the inferior colliculus
Authors: Strominger Norman L. , Oesterreich Roger E.
Published: December 2004

Nine adult cats were trained on a discrimination requiring localization of sound in space. Localization was tested at successively decreasing discrimination angles, and thresholds were determined. The brachium of the inferior colliculus was sectioned bilaterally either in a single operation or in two stages with intervening behavioral tests. Large transient losses in localizing ability were found in three animals with complete unilateral brachium lesions. While performance improved with protracted retraining, two of these animals had some permanent impairment. Following complete bilateral lesions of the acoustic brachium, animals were not able to localize sound as tested by the present methods. In a single animal, extensive but bilaterally incomplete destruction of the brachium was without effect on localization.
The rubro‐spinal tract of the opossum (Didelphis virginiana)
Authors: Martin George F. , Dom Richard
Published: December 2004

The course, caudal extent and termination of the opossum rubro‐spinal tract were determined by employing the Nauta‐Gygax and Fink‐Heimer techniques on the spinal cords of animals with lesions either within the red nucleus or within the descending fibers emanating from that nucleus. Prior to placement of the lesion, the area at the tip of the electrode was stimulated and the concomitant movements of skeletal muscles were palpated.

The rubro‐spinal tract traversed the entire length of the spinal cord and was located within the dorsolateral portion of the lateral funiculus. The tract was partially separated from the surface throughout cervical and thoracic levels by fibers of the dorsal spino‐cerebellar tract. More caudally the rubro‐spinal tract coursed immediately beneath the cord surface.

At cervical levels, rubro‐spinal fibers ended extensively within the lateral portion of laminae V and VI (Rexed, '52) and minimally within the medial portions of the same laminae. Fascicles also ended within lamina VII. At thoracic levels, lamina VI disappeared and rubro‐spinal fibers terminated within the lateral and, to a lesser extent, the medial portions of laminae V and VII. Lamina VI was present at lumbar and rostral sacral levels and the majority of rubro‐spinal fibers ended within the lateral part of that lamina. However, a few fibers terminated within laminae V and VII at such levels. At caudal sacral and coccygeal levels lamina VI disappeared and rubro‐spinal bundles ended within laminae V and VII.

Stimulation of the caudal red nucleus initiated contraction of the flexor musculature of the contralateral forelimb, and to a lesser degree, the contralateral hindlimb. Contraction of the contralateral paraxial musculature was also noted at cervical and thoracic levels during such experiments. Stimulation of the rubro‐spinal tract and adjacent tegmentum immediately caudal to the red nucleus resulted in similar movements, but they were essentially limited to the side of the stimulation.
Monoamine‐containing neurons in planaria
Authors: Welsh John H. , Williams Lois D.
Published: December 2004

The Falck and Hillarp fluorescence method was used in a study of the identification and distribution of monoamine‐containing neurons in three species of planarians, with principal attention given to Phagocata oregonensis. Nerve cells containing 5‐hydroxytryptamine (5HT) and others containing a primary catecholamine (CA) were found in the cerebral ganglia and ventral nerve cords; also in the peripheral plexus and pharynx. The fluorescing components of the peripheral plexus are mostly CA‐containing in dorsal regions and 5 HT‐containing in ventral regions. Some 5HT cells have processes that penetrate the ventral epidermis. These may be sensory or they may have a cilio‐regulatory role. A typical nerve net of multipolar CA cells was found in the pharynx; also a deeper layer of 5HT cells. The occurrence of other types of neurons (cholinergic and neurosecretory) in planarians is discussed. The early evolution of various common chemical types of nerve cells is indicated.
The development of the human motor trigeminal complex and accessory facial nucleus and their topographic relations with the facial and abducens nuclei
Authors: Jacobs Miriam J.
Published: December 2004

The development of the motor trigeminal complex and accessory facial nucleus was traced in 23 human fetuses (seven and one‐half to 21 weeks, menstrual age; 20.7–p177.5 mm CR length) and a 75‐day infant both by graphic reconstructions and cytologic methods. Positional relationships with the facial and abducens nuclei were determined.

Differentiation begins at the junction of the posterior trigeminal and accessory facial nuclei (level of pontine flexure) and proceeds rostralward in the motor trigeminal complex and caudalward in the facial complex. The neurons that differentiate earliest complete their migration first and migrate the least from their original position. Thus the posterior trigeminal nucleus is most dorsally and the accessory facial cell groups are most medially located. Migration of the trigeminal complex is completed by eitht weeks and of the facial complex by ten to ten and one‐half weeks.

Correlations are made between the differentiation of the motor neurons of the trigeminal and facial nerves and: (1) the development of the muscles that they have been postulated to supply; (2) the known function of these muscles; (3) the development of reflex activity in these muscles; (4) the mammalian experimental and human pathologic evidence for their innervation. These correlations support the view that the posterior trigeminal nucleus supplies the anterior belly and the accessory facial nucleus the posterior belly of the digastric muscle and that the posterodorsal part of the motor trigeminal nucleus innervates the mylohyoid muscle. Furthermore, the sequence of differentiation of the trigeminal complex indicates that the ventral trigeminal muscles (floor of the mouth) are represented primarily dorsally and posteriorly in the trigeminal complex and the progressively more dorsal muscles increasingly farther ventrally and anteriorly.

The three subdivisions of the motor trigeminal nucleus are probably related to the three major embryonic muscle masses that they supply early in development. Because the inconstant subgroups in the three subdivisions appear when the complixity of reflex activity increases, perhaps they represent functional units rather than single muscles.

The position of the abducens nucleus varies widely and no consistent migration cephalad occurs. It may reach caudal motor trigeminal nuclear levels early in fetal life or remain at caudal levels of the facial nucleus postnatally. No accessory abducens nucleus was identified. The neurons in the location allocated to it in some mammals develop from the common cell column between the motor trigeminal nucleus and the facial nucleus and constitute the accessory facial nucleus. Possible explanations for the widely different number of cells in the posterior trigeminal and accessory facial nuclei are discussed.
Comparisons in structure of tendon organs in the rat, cat and man
Authors: Bridgman Charles F.
Published: December 2004

Golgi tendon organs from human, cat and rat extensor digitorum brevis muscles are compared in structural design. Microscopic studies reveal that these receptors appear to be very similar in structure, suggesting close functional similarities even though they are largest in man, intermediate size in cats and smallest in rats. This contrasts with similar observations on the structure of muscle spindles which show strong differences in respect to the insertion of intrafusal muscle fibers thereby implying species specialization of response characteristics to intramuscular tensions and pressures.

Reconstructive drawings of human tendon organs from serial sections suggest how sensory endings may be affected by tensions at the musculotendinous junctions due to stretch or contraction of motor units. Finely divided collagen bundles appear to compress and distort nerve endings lying between them, thus inducing the generation of spike discharges.
Topical projection of the olivocerebellar system in the cat: An electrophysiological study
Authors: VanGilder John C. , O'Leary James L.
Published: December 2004

Using electrophysiological recording, topical aspects of the olivocerebellar projection were studied in the locally anesthetized cat immobilized with Flaxedil. Transcortical evoked potentials were recorded simultaneously from eight electrodes distributed over the cerebellar surface, and averaged with a LINC computer. Precautions were taken to eliminate virtual potentials from this volume conductor situation. The evoked potentials consisted of a 4–6 msec positive spike, latency 4.5–7 msec, followed by a 15–30 msec slow negative deflection. Each was recorded from one or two folia contralateral in distribution. Medial and dorsal accessory nuclei project largely to cerebellar vermis. A rostrocaudal relationship was found between posterior vermis and medial accessory nucleus, and vermal anterior lobe received its projection from the caudal and midportions of medial and dorsal accessory components. A dense representation of accessory nucleus responses was present over the declive as compared with other cerebellar areas. Paravermal responses of anterior lobe derived from rostral dorsal accessory olive, and principal olive connected to the hemispheral region. The ventral lamella of principal olive projected to Crus II, dorsal lamella to Crus I. These lobules are represented rostrally in the principal nucleus, whereas the source for paramedial lobules was situated more caudally. The results correlate well with the retrograde degeneration studies of Brodal ('40, '54) but differ in the detail of some projections.
Thalamotelencephalic projections in the turtle (Pseudemys scripta)
Authors: Hall William C. , Ebner Ford F.
Published: December 2004

The telencephalic projections of the turtle thalamus were studied using the Fink‐Heimer ('67) technique for staining degenerated axons and their terminals. Large thalamic lesions produced terminal degeneration in the basal telencephalic nuclei, the core of the dorsal ventricular ridge and the outer half of layer I in general cortex. A variety of control lesions confirmed that these projections arise in the thalamus. Circumscribed thalamic lesions revealed first, that there is some degree of spatial organization in the turtle's thalamocortical projection system and second, that at least one sensory relay nucleus, the dorsal lateral geniculate, projects to general cortex. Detailed comparisons of the turtle's thalamotelencephalic projections with those present in two primitive mammalian species, the hedgehog and the opossum, provided a basis for identifying probable homologies in the forebrains of reptiles and mammals.