Showing papers by "University of California, San Diego published in 1978"

Catecholamine innervation of the basal forebrain. IV. Topography of the dopamine projection to the basal forebrain and neostriatum.

Abstract: In this study the location of dopamine (DA) neuron perikarya in the rostral mesencephalon of the rat was determined using the glyoxylic acid fluorescence histochemical technique. Subsequently the topography of the projection of these mesencephalic neurons on the basal forebrain and striatum was analyzed using the anterograde transport-autoradiographic tracing method and the retrograde transport-horseradish peroxidase (HRP) technique. The results of these anatomical studies were correlated with the biochemical and histochemical studies presented in previous reports (Moore, 1978; Fallon and Moore, 1978; Fallon et al., 1978) to provide the following conclusions. The topography of the DA neuron projection on the basal forebrain and neostriatum is organized in three planes, dorsal-ventral, medial-lateral and anterior-posterior. DA cells are found almost exclusively in the substantia nigra (SN) and ventral tegmental area (VTA). Ventral cells of the SN and VTA project to the dorsal structures of the basal forebrain such as the septum, nucleus accumbens and neostriatum. The latter includes some DA cells located ventrally in the pars reticulata of the SN. Dorsal cells project to ventral structures. The medial-lateral topography is organized such that the medial sectors of the SN-VTA area project to the medial parts of nuclei in the basal forebrain and neostriatum whereas lateral sectors of the SN-VTA area project to the lateral parts of nuclei in the basal forebrain and neostriatum. An anterior-posterior topography also is evident such that anterior parts of the SN-VTA project anteriorly whereas the posterior SN-VTA projects more posteriorly in these areas. These observations are consistent with the view that the DA neurons of the SN-VTA complex form a single nuclear group with a highly topographically organized projection innervating not only deep nuclei of the telencephalon but allocortical structures as well.

Prestimulus Effects on Human Startle Reflex in Normals and Schizophrenics

Abstract: Graham (1975) demonstrated that a weak prestimulus could effectively inhibit or facilitate the eyeblink component of the startle reflex in humans, depending on the temporal duration of the prestimulus. This study had three goals: 1) to replicate the findings of Graham, 2) to establish the reliability of this phenomenon by a test-retest comparison, and 3) to compare the eyeblink reflex response of normal subjects with schizophrenic subjects. Seven prestimulus durations of continuous tone (from 0 to 2000 msec) were presented to 20 normal subjects and the results confirmed that maximal inhibition of eyeblink amplitude occurred in the 120 msec prestimulus condition. Increased amplitude occurred nonsignificantly when the prestimulus lasted for 2000 msec. On retest, 14 normal subjects showed a significant degree of reliability. When 20 normal subjects were compared to 12 schizophrenic subjects, significant differences in eyeblink response were found for blink amplitude and latency in the 60 msec prestimulus condition. This change is consistent with information processing “overload” theories of sensory overstimulation in schizophrenia. The blink reflex is a rather stable phenomenon and is probably altered in schizophrenia and/or by antipsychotic medication.

The Mussel Watch

Abstract: The levels of four sets of pollutants (heavy-metals, artificial radionuclides, petroleum components, and halogenated hydrocarbons), have been measured in U.S. coastal waters, using bivalves as sentinel organisms. The strategies of carrying out this programme are outlined and the results from the first year's work are given. Varying degrees of pollution in U.S. coastal waters have been indicated by elevated levels of pollutants in the bivalves, which comprised certain species of mussels and oysters and were collected at over one hundred localities.

Serotonin neurons of the midbrain raphe: ascending projections.

Abstract: The ascending projections of serotonin neurons of the midbrain raphe were analyzed in the rat using the autoradiographic tracing method. Axons of raphe serotonin neurons ascend in the ventral tegmental area and enter the medial forebrain bundle. A number of fibers leave the major group to ascend along the fasciculus retroflexus. Some fibers enter the habenula but the majority turn rostrally in the internal medullary lamina of the thalamus to innervate dorsal thalamus. Two additional large projections leave the medial forebrain bundle in the hypothalamus; the ansa peduncularis-ventral amygdaloid bundle system turns laterally through the internal capsule into the striatal complex, amygdala and the external capsule to reach lateral and posterior cortex, and another system of fibers turns medially to innervate medial hypothalamus and median eminence and form a contrelateral projection via the supraoptic commissures. Rostrally the major group in the medial forebrain bundle divides into several components: fibers entering the stria medullaris to terminate in thalamus; fibers entering the stria terminalis to terminate in the amygdala; fibers traversing the fornix to the hippocampus; fibers running through septum to enter the cingulum and terminate in dorsal and medial cortex and in hippocampus; fibers entering the external capsule to innervate rostral and lateral cortex; and fibers continuing forward in the medial olfactory stria to terminate in the anterior olfactory nucleus and olfactory bulb.

Composition and development of the continental tectosphere

Abstract: Beneath the old continental nuclei are thick root zones which translate coherently during plate motions. These zones are apparently stabilised against convective disruption by the depletion of the continental upper mantle in a basalt-like component. Construction of this delicately balanced tectosphere is accomplished by the dynamic and magmatic processes of the Wilson cycle.

The Effects of Campaign Spending in Congressional Elections

Abstract: Incomplete understanding of the connection between campaign spending and election outcomes hindered evaluation of enacted and proposed congressional campaign finance reforms. Reanalysis of the 1972 and 1974 House of Senate campaign spending data using both OLS and 2SLS regression models shows that spending by challengers has a much greater impact on the outcome than does spending by incumbents. A similar analysis of the effects of spending on voters' recall of candidates in the 1972 and 1974 SRC surveys supports the explanation that campaign expenditures but nonincumbents the necessary voter recogniton already enjoyed by incumbents prior to the campaign. The 1974 survey questions on Senate candidates indicate that, although the inability to remember candidates' names does not preclude having opinions about them, voters recalling candidates are much more likely to offer more negatives well as positive evaluations (though positive outnumber negative); familiarity is not automatically advantageous. And voters' evaluations of candidates strongly influence how they vote. The implications of these findings for congressional campaign finance policy are readily apparent.

Catecholamine innervation of the basal forebrain II. Amygdala, suprarhinal cortex and entorhinal cortex

Abstract: The catecholamine (CA) innervation of the posterior basal forebrain, the amygdala, suprarhinal cortex and entorhinal cortex, was studied in the rat using biochemical assay and fluorescence histochemistry. The assay studies demonstrate a moderate norepinephrine (NE) content in the amygdala and entorhinal cortex with a lower value for the suprarhinal cortex. Following destruction of the locus coeruleus, the decrease in NE content of these basal forebrain structures indicates that their principal NE innervation is from locus coeruleus. An additional small NE input arises from the medullary NE neuron groups. Ablation of dopamine (DA) cell groups (substantia nigra-ventral tegmental area, SN-VTA) indicates that the DA input to the amygdala arises from the lateral VTA and medial half of the SN. Fluorescence histochemical studies using the glyoxylic acid-Vibratome technique demonstrate the presence of four distinct types of CA neuron terminal plexus in the posterior basal forebrain. These include two different DA fiber types arising in SN-VTA, small NE fibers with small varicosities arising in locus coeruleus and NE fibers with larger varicosities arising in other brainstem NE cell groups. The large NE fibers appear to enter the amygdala via the ansa peduncularis-ventral amygdaloid bundle to innervate the central and basolateral nucleus and the anterior amygdaloid area. The locus coeruleus NE fibers appear to enter the posterior basal forebrain via both the stria terminalis and ansa peduncularis-ventral amygdaloid bundle system to form a moderately dense innervation of the central and basolateral nuclei of the amygdala and a less dense innervation of the other areas. The DA neuron axons are concentrated in the central and basal nuclei and intercalated cell groups. Other areas receive a more diffuse DA input, with the exception of the moderately dense innervation of the suprarhinal cortex and DA “islands” in the ventral-anterior entorhinal cortex. The DA input to the posterior basal forebrain is complex and heterogeneous and the axonal morphology differs greatly among the terminal fields within the amygdala and adjacent cortical areas.

Rank-one modification of the symmetric eigenproblem

Abstract: An algorithm is presented for computing the eigensystem of the rank-one modification of a symmetric matrix with known eigensystem. The explicit computation of the updated eigenvectors and the treatment of multiple eigenvalues are discussed. The sensitivity of the computed eigenvectors to errors in the updated eigenvalues is shown by a perturbation analysis.

Occurrence of glutathione in bacteria.

Abstract: Glutathione and soluble thiol content were examined in a broad spectrum of bacteria. Significant soluble thiol was present in all cases. The thiol compound was glutathione in most of the gram-negative bacteria but not in most of the gram-positive bacteria studied. Glutathione was absent in four anerobes and one microaerophile but was present in a blue-green bacterium. The glutathione content of Escherichia coli increased significantly during transition from exponential to stationary phase.

Acute compartment syndromes: diagnosis and treatment with the aid of the wick catheter.

Abstract: Intracompartmental pressures were measured by the wick catheter technique in sixty-five compartments of twenty-seven patients who were clinically suspected of having acute compartment syndromes. A pressure of thirty millimeters of mercury or more was used as an indication for decompressive fasciotomy. The range of normal pressure was from zero to eight millimeters of mercury. Eleven of these patients were diagnosed as actually having compartment syndromes and in these patients, twenty-seven compartments were decompressed. Only two patients had significant sequelae. In the sixteen patients (thirty-eight compartments) whose pressures remained less than thirty millimeters of mercury, fasciotomy was withheld and compartment syndrome sequelae did not develop in any patient. Intraoperatively the wick catheter was used continuously in eight patients to document the effectiveness of decompression. Fasciotomy consistently restored pressures to normal except in the buttock and deltoid compartments, where epimysiotomy was required to supplement the fasciotomy. Continuous intraoperative monitoring of pressure by the wick catheter technique allowed us to select the few cases in which primary closure of wounds was appropriate and to decide which patients were best treated with secondary closure.

Studies on the functional role of tintinnids in the Southern California Bight. I. Grazing and growth rates in laboratory cultures

Abstract: Five species of tintinnids, Amphorella quadrilineata (Claparede and Lachmann, 1858), Tintinnopsis cf. beroidea Stein (1867), T. cf. acuminata Daday (1887), Eutintinnus pectinis (Kofoid and Campbell, 1929), and Helicostomella subulata (Ehrenberg, 1833), were isolated from Southern California coastal waters and maintained in laboratory cultures which were used to investigate, several aspects of the feeding dynamics and population growth rates of this group of planktonic ciliates. Data are most complete for the latter three species. Both E. pectinis and H. subulata displayed ingestion and growth rates which increased with increasing food concentration until a maximum rate was obtained which then remained essentially constant as food levels increased further. Maximum hourly ingestion was equivalent to approximately 10 to 20% of the body weight of the tintinnids. T. cf. acuminata showed no such maximum ingestion rate, as ingestion rates increased throughout the entire range of food concentrations used. The dependence of growth rate of T. cf. acuminata on food concentration also differed from the other species, being characterized by a broad region of maximum growth at intermediate food levels with reduced growth at both lower and higher food concentrations. Maximum observed growth rates represented doubling times of approximately 12 h for both E. pectinis and T. cf. acuminata and 24 h for H. subulata. The data suggested gross growth efficiencies exceeding 50% over much of the range of food concentrations used. No strong evidence supporting the existence of feeding thresholds or “switching” behavior was collected during these experiments, although apparently selective feeding was observed in one experiment with E. pectinis.

The distribution of blood rheological parameters in the microvasculature of cat mesentery.

Abstract: In vivo studies of the rheological behavior of blood in the microcirculation were conducted by direct in situ measurements in cat mesentery. Upstream to downstream pressure drops were measured in unbranched arterioles, capillaries, and venules, with diameters from 7 to 58 micrometer. Simultaneous measurements of red cell velocity and vessel geometry facilitated computation of bulk velocity, pressure gradient, apparent viscosity, wall shear stress, and resistance. Arteriovenous distributions of these parameters revealed the following. Maximum pressure gradient (0.015 cm H20/micrometer) occurs in the true capillaries (7 micrometer in diameter); intravascular wall shear stress averaged 47.1 dynes/cm2 in arterioles and 29.0 dynes/cm2 in venules. Extreme values as great as 200 dynes/cm2 were observed in a few shunting arterioles. Apparent viscosity averaged 3.59 cP in arterioles, 5.15 cP in venules, and 4.22 cP overall. Intravascular resistance per unit length of microvessel varied with luminal diameter as a p...

Structure and tectonic history of the Eastern Panama basin

Abstract: New marine geophysical data allow the preparation of revised bathymetric and magnetic anomaly charts of the Panama Basin and demonstrate that the eastern part of the basin, between the fracture zone at long 83°W and the Colombian continental margin, was formed by highly asymmetric sea-floor spreading along the boundary of the Nazca and Cocos plates 27 to 8 m.y. B.P. Lineated magnetic anomalies recording this history are oriented approximately east-west. The oldest set of north-flank anomalies overlaps in age with those adjacent to the Grijalva scarp, south of the western Panama Basin, where they are oriented 065°. Younger anomalies (5C to 5) in the eastern basin are approximately parallel to anomalies of this age identified on the Carnegie platform and the flanks of the Costa Rica rift. The eastern basin now contains a pattern of fossil spreading centers (including the Malpelo rift) and transform faults (including the Yaquina graben) that were abandoned 8 m.y. B.P. by a shift in plate boundaries that transferred a large section of the Cocos plate to the Nazca plate. Cessation of Nazca-Cocos spreading east of long 83°W was heralded by a 3-m.y. deceleration of spreading on the eastern segments, which created rough topography and axial rift valleys typical of slow-spreading ridges. Westward jumping of the Nazca-Cocos-Caribbean triple junction rejuvenated the northern segment of the fracture zone at long 83°W, causing uplift of the adjacent Coiba Ridge. Recently, active transform faulting has jumped farther west, from the foot of the Coiba Ridge to the Panama fracture zone. Apart from changes in plate boundaries, the main event in the tectonic evolution of the region was initiation about 22 to 20 m.y. B.P. of the hot spot that created the Malpelo, Cocos, and Carnegie Ridges. Precursors of effusive ridge-building volcanism included major fracturing of the oceanic crust to the north of the present Malpelo Ridge. Both processes hamper identification of magnetic anomalies in the vicinity of the ridges. Our interpretation of the tectonic history is also incomplete in the easternmost parts of the basin, where data are insufficient; this impairs our interpretation of the adjacent continental geology in terms of changing interaction between oceanic and continental plates. The geologic history of the Isthmus of Panama is compatible with our application of the plate-tectonic model.

Risk factors for the development of cholelithiasis in man (first of two parts).

Abstract: Conditions Associated with Pigment Stones The demographic characteristics of persons at high risk for pigment gallstones differ from those in whom cholesterol stones are likely to develop, as noted

The bio-optical state of ocean waters and remote sensing 1

Abstract: The diffilse attenuation cocfficicnt for irradiance, KT, is a physical measure of the bio-optical state of ocean waters. From an analysis of irradiance, KT, and pigment concentration, the specific attenuation due to chlorophyll-like pigments is found to bc 0.016 +- 0.003 Irn-’ (mg pigment m-“)-‘I. The bio-optical state of ocean waters can be remotely sensed by spacecraft sensors. KT is readily measured at sea and is highly correlated with and dependent on the chlorophyll-like pigment concentration, C K. This pigment concentration and KT provide a measure of the fraction of radiant energy attenuated by phytoplankton. This fraction, in turn, is closely related to the production equations formulated by Bannister and can be directly incorporated into a general theory of phytoplankton dynamics. CK may also be used as an index of primary prodlrctivity. The determination of the bio-optical state of ocean waters by surface vessel provides direct information concerning the productivity of these waters; to the extent that the bio-optical state can be determined by satellite, it may be possible to examinc important paramctcrs of the marine ecosystem rapidly and repeatedly. The rcmotc sensing from spacecraft of the upwelling spectral radiant energy from the ocean’s surface makes it possihlc to determine marine pigment conccntrations due to phytoplankton. This, in turn, suggests the potential for obtaining rapid worldwide assessments of primary productivity over time scales required to link this productivity to commercially important fisheries. Continuous worldwide data on ocean productivity would assist synoptic ecological studies of ocean regions of special interest, provide othcrwise unattainable data for the dynamic modcling of phytoplankton, and allow for the continuous monitoring of variations in productivity. If these expectations for remote sensing are to bc fully realized, technical methods for detecting and analyzing the upwelling radiant energy must bc perfected and relationships between ocean optical properties and the biological parameters affecting thcsc optical properties must bc quantitatively investigated. Possible techniques for detecting

Fluorescence correlation spectroscopy. III. Uniform translation and laminar flow

Abstract: We extend fluorescence correlation spectroscopy to systems that undergo translation or laminar flow in a sample cell. We include theoretical and experimental results; we consider uniform and nonuniform velocity profiles. Concentration correlation analysis extracts microscopic rate parameters from measurements of the spontaneous concentration fluctutations, which occur even at equilibrium. Fluorescence is one of the most sensitive means of monitoring these fluctuations. Analysis of flowing or translating systems (1) offers a method of measuring number concentrations of selected species, for example, of aggregates or polymers, (2) provides a nonperturbing velocity probe, (3) sometimes allows one to circumvent photolytic degradation, (4) has proved extremely helpful in testing and aliging apparatus for fluorescence correaltion measurement and in verifying theoretical analyses, and (5) may be required for interpretation of results obtained on systems in motion, even though that motion is undesired or initially unsuspected. We include both theoretical and experimental results for combined Poiseuille flow and diffusion in the geometry which is of most practical interest. Theoretical expressions for the much simpler cases of nondiffusive Poiseuille flow as well as uniform flow or translation with or without diffusion constitute limiting cases which are displayed explicitly.

Stimulation of Aromatase Activity by Follicle Stimulating Hormone in Rat Granulosa Cells in Vivo and in Vitro

Abstract: The role of FSH in the activation of aromatase enzymes in granulosa cells was studied by using immature, hypophysectomized, estrogen-primed rats as a model system. After twice daily injections of ovine FSH, aromatase activity was induced in granulosa cells after a 24-h lag period. Continued FSH treatment caused a further increase in aromatase activity. After 48 h, the enzyme activity was comparable to that found in granulosa cells of adult preovulatory follicles. The effects of enzyme substrate (androstenedione) as well as purified FSH and LH upon aromatase activity were investigated in vitro by culturing granulosa cells for 2 days in a chemically defined medium containing these hormones. In the absence of aromatase substrate, no significant stimulation of estrogen secretion was observed in control and gonadotropin-treated cultures. However, in the presence of enzyme substrate (10-7 M androstenedione), highly purified FSH (200 ng/ml), but not LH (200 ng/ml), stimulated estrogen production 8.8- and 40-fold...

Updating the singular value decomposition

Abstract: LetA be anmA—n matrix with known singular value decomposition. The computation of the singular value decomposition of a matrixAƒ is considered, whereAƒ is obtained by appending a row or a column toA whenmÂ?n or by deleting a row or a column fromA whenm>n. An algorithm is also presented for solving the updated least squares problemAƒ yÂ?bÂ?, obtained from the least squares problemAxÂ?b by appending an equation, deleting an equation, appending an unknown, or deleting an unknown.

The Effect of A General Aspherical Perturbation on the Free Oscillations of the Earth

Abstract: summary. The Lagrangian governing the infinitesimal elastic-gravitational oscillations of a completely general earth model with interior fluid—solid boundaries is given. Rayleigh's principle is then used to derive a formula for calculating the first-order perturbations in the eigenfrequencies due to an arbitrary slight perturbation of a spherically symmetric, non-rotating, isotropic starting model. The perturbations considered include rotation, asphericity, elastic anisotropy, and a deviatoric initial stress, as well as a change in the positions of both welded and fluid—solid boundaries.