Search PubMed⌕ Search

Biomedical subjects

C S Lin

Publications and source records attributed to C S Lin.

At least 289 records · Page 16Linked to original sources
PubMed1980

Effect of adrenergic agonists on big and small renin.

The effect of alpha- and beta-adrenergic agonists on renal and submaxillary renin of different molecular weights was studied using male albino mice as experimental animals. Phenylephrine or isoproterenol was administered intravenously after removal of the submaxillary glands and/or kidneys. Renin was isolated from plasma by column chromatography and then measured by a direct radioimmunoassay. Phenylephrine increased both 68,500-dalton renin (big renin) and 38,000-dalton renin (small renin) in the plasma of nephrectomized mice. Isoproterenol increased big and small renin in the plasma of mice whose submaxillary glands were removed. In both cases, the increase of small renin was significantly greater than that of big renin. The results suggest that the alpha-adrenergic agonist phenylephrine affects the submaxillary gland, leading to the increase of both big and small plasma renin. In contrast, the beta-adrenergic agonist isoproterenol affects the kidney, leading to the increase of both big and small plasma renin.

Animals↗
PubMed1980

Spasmolytic action of verapamil, D600 and cinchocaine on the rat vas deferens.

The inhibitory action of verapamil, D600 and a local anesthetic, cinchocaine (CE) was studied on the isolated rat vas deferens. All three drugs inhibited norepinephrine (NE) and KCl dose-response curves in a concentration-dependent manner. Verapamil and D600 were approximately equivalent in their inhibitory effect but were significantly more potent (p < .05) than CE. Cinchocaine enhanced NE dose-response curves prior to inhibition at higher concentrations but did not affect KCl dose-response curves similarly. Inhibition of NE dose-response curves by CE and low concentrations of D600 showed significant negative correlation with the concentration of calcium in the medium. However, inhibition caused by high concentration of D600 (1 X 10(-5) M0 was unaffected by a 10-fold increase in calcium concentration. Contractile responses of the vas deferens to single doses of NE (1 X 10(-4) M) or KCl (40 mM) comprise of an initial fast (F) component and a slow (S) component. The inhibition of the F-component of NE- and KCl-induced responses by D600 and CE was inversely related to the concentration of calcium. Inhibition of the S-component of NE-induced respnses by both drugs was not correlated with calcium levels in contrast to that of KCl-induced responses where the inhibition showed significant negative correlation with the calcium content of the medium. Our results indicate D600 differs from CE in its effects on response to NE but that it is qualitatively similar to CE in its inhibition of KCl-induced responses.

Animals↗
PubMed1979

The inferior pulvinar complex in owl monkeys: architectonic subdivisions and patterns of input from the superior colliculus and subdivisions of visual cortex.

Patterns of connections with other visual structures and architectonic characteristics were used to subdivide the inferior pulvinar complex of owl monkeys into three distinct nuclei termed the central inferior pulvinar, IPc, the medial inferior pulvinar, IPm, and the posterior inferior pulvinar, IPp. IPc occupies about 70%; IPm about 20%, and IPp about 10% of the inferior pulvinar complex. Encapsulating fiber bands distinguish the boundaries of the three nuclei. IPm is also identified by a much greater packing density of neurons than IPc and IPp. Both IPp and IPc receive input from the superior colliculus, but the terminations in IPp are denser. Visual cortical Areas 17, 18, MT, DM, M and PP (Allman and Kaas, '76) project to IPc and IPm in patterns that indicate that central vision is represented dorsorostrally and peripheral vision ventrocaudally in both nuclei. Terminations in IPm from Area MT are particularly dense. None of these visual areas projects to IPp. Rather, input to IPp appears to originate in cortex rostral to Area MT in the temporal lobe.

Animals↗
PubMed1979

Subcortical projections of six visual cortical areas in the owl monkey, Aotus trivirgatus.

Subcortical projections of six visual cortical areas (Areas 17 and 18, the Middle Temporal, Dorsomedial and Medial Areas, and the Posterior Parietal Region) in the owl monkey, Aotus trivigatus, were investigated with autoradiographic methods following injections of tritiated proline. No contralateral projections were demonstrated. While some brainstem structures received input from all six subdivisions of cortex, each cortical area appeared to exhibit its own unique pattern of subcortical projections. All six cortical areas were found to project to the superior and inferior divisions of the pulvinar, reticular nucleus of the thalamus, pretectum and superior colliculus. Other subcortical targets of one or more visual cortical areas were the basal ganglia, claustrum, zona incerta, one or more of the intralaminar nuclei, lateral posterior nucleus, pregeniculate nucleus, dorsal lateral geniculate nucleus, and pontine nuclei. Furthermore, details of corticofugal projections to the dorsal lateral geniculate nucleus, pretectum and superior colliculus varied with the cortical area studied. The projections to the reticular nucleus, pregeniculate nucleus, dorsal lateral geniculate nucleus, the inferior and a portion of the superior division of the pulvinar and the superior colliculus were found to be topographically organized. The targets of the subcortical projections were compared with those of the retina, as revealed by autoradiographic methods following tritiated proline injections of the eye and were found to overlap to varying extents in the superior colliculus, pretectum and dorsal lateral geniculate nucleus and to be segregated in the pregeniculate nucleus. The results substantiate the validity of previous studies in the owl monkey that suggest that the visual cortex is subdivided into several functionally distinct areas; and illustrate the complexity of corticofugal influence on visual processing.

Animals↗
PubMed1979

Isolation of a single polypeptide leucyl-tRNA synthetase from bakers' yeast.

A single polypeptide of leucyl-tRNA synthetase (LRS) has been purified from budding bakers' yeast by a modification of the procedure published earlier. On denaturing polyacrylamide gel electrophoresis LRS was one band corresponding to molecular weight of 120,000 +/- 5,000 daltons. Variable amounts of LRS with a similar molecular weight but which dissociated into equal subunits of 58,000 were also isolated. The affinities (KM) for substrates for this form of the enzyme were similar to those previously reported for the dimeric form of the enzyme.

Amino Acyl-tRNA Synthetases↗
PubMed1979

Connections of areas 3b and 1 of the parietal somatosensory strip with the ventroposterior nucleus in the owl monkey (Aotus trivirgatus).

Anatomical tracers were injected into electrophysiologically defined sites in somatosensory cortical Area 3b (SI proper) and Area I (posterior cutaneous field) of owl monkeys after these cortical subdivisions had been extensively explored in microelectrode mapping experiments. These mapping experiments revealed that both Areas 3b and 1 contain complete and separate representations of the body surface (Merzenich et al., '78). Restricted injections of the retrograde tracer, horseradish peroxidase (HRP), into either Area 3b or Area 1 labeled neurons within a band of cells in the ventroposterior nucleus (VP). The location of the labeled band in VP varied with the location of the injection site in both representations, and the labeled region of VP was overlapping for injections in corresponding body parts in the two representations. Neurons projecting to the hand and foot cortical representations were in architectonically identified subnuclei. Because injections into either Area 3b or Area 1 labeled over half of the neurons in the appropriate regions of VP, it appears that some neurons in VP project to both cortical representations. Finally, injections of HRP combined with the anterograde tracer, 3H-proline, indicate that VP neurons are reciprocally interconnected with both Areas 3b and 1.

Animals↗
PubMed1979

Multiple representations of the body within the primary somatosensory cortex of primates.

Microelectrode mapping experiments indicate that the classical primary somatosensory cortex of monkeys consists of as many as four separate body representations rather than just one. Two complete body surface representations occupy cortical fields 3b and 1. In addition, area 2 contains an orderly representation of predominantly "deep" body tissues. Area 3a may constitute a fourth representation.

Animals↗
PubMed1978

Subcortical projections of the dorsomedial visual area (DM) of visual association cortex in the owl monkey, Aotus trivirgatus.

The efferent subcortical connections of the dorsomedial cortical visual area (DM) in the owl monkey were determined by tracing degenerating axons following lesions or by tracing axonal pathways following injection of radioactively labeled proline. Areas of termination included structures which are known to receive input from many other regions of cortex such as the claustrum, putamen, caudate nucleus, reticular nucleus of the thalamus and pontine nuclei. Other terminations were in subcortical structures which primarily receive input from visual area: these included the pregeniculate nucleus, the medial and central divisions of the inferior pulvinar nucleus, two loci in the superior pulvinar complex, the pretectum and the superior colliculus. Terminations were also seen in the lateral posterior nucleus, a part of the thalamus associated with the somatosensory system. These results further identify Area DM as an integral part of the visual system, suggest functional subdivisions of the pulvinar complex, and implicate the lateral posterior nucleus in the mediation of visual, as well as somatosensory, behavior.

Animals↗