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Biomedical subjects

C S Lin

Publications and source records attributed to C S Lin.

At least 307 records · Page 17Linked to original sources
PubMed1977

Projections from cortical visual areas 17, 18, and MT onto the dorsal lateral geniculate nucleus in owl monkeys.

Projections from cortical visual Areas 17, 18, and MT to the dorsal lateral geniculate nucleus of owl monkeys were revealed by the use of the autoradiographic tracing method. Restricted injections of 3H-proline into Area 17 resulted in dense columns of labeled tissue extending through all layers of the nucleus and roughly perpendicular to the layers. There was some lateral spread of the label in the interlaminar zones. Projections from Areas 18 and MT were distributed over the ventral layers of the nucleus including the magnocellular layers, layer S, and the adjoining interlaminar zones. The input from Area 18 was relatively sparse. The projections from all three cortical visual areas appear to connect homotopic locations in the geniculate and cortical representations of the visual field.

Animals↗
PubMed1977

Cortical projections of posterior parietal cortex in owl monkeys.

Efferent cortical projections of posterior parietal cortex were determined by degeneration and autoradiographic methods in owl monkeys. Intraregional connections were to the immediate surround of the injection or lesion site, and to distinct foci within the posterior parietal region. The extraregional ipsilateral connections were with (1) previously established subdivisions of visual association cortex (the Dorsomedial Area, the Medial Area, the Dorsolateral Area, and the Middle Temporal Area), (2) other locations in caudal neocortex, and (3) frontal cortex. The callosal projections were to separate foci in posterior parietal cortex of the contralateral cerebral hemisphere. The separate foci of both ipsilateral and contralateral terminations in posterior parietal cortex raise the possibility that this region contains more than one functional subdivision. The connections with visual association cortex suggest a role for parietal cortex in visual behavior. Other foci in caudal neocortex indicate the possible locations of additional subdivisions of association cortex.

Animals↗
PubMed1977

Progesterone retention by rat uterus I. Pharmacokinetics after uterine intraluminal instillation.

Tritium-labeled progesterone was administered to mature female rats in the proestrous stage by three different routes, gastric intubation, subcutaneous injection, and uterine intraluminal instillation, to study the kinetics involved in the uptake and retention of radioactivity by the uterus and various other tissues. Progesterone was retained at a much higher level and for a more prolonged period in the rat uterus after uterine intraluminal instillation. Progesterone bioavailability to the uterus was 45 times higher by uterine intraluminal instillation than by either gastric intubation or subcutaneous injection. Progesterone absorption by the rat endometrium was extremely fast. The observed biphasic decrease of radioactivity from the uterine tissue was explained adequately by a pharmacokinetic model in which progesterone is assumed to be present in two compartments within the uterine tissue. The pharmacokinetic parameters showed that the progesterone biological half-life in the uterine tissue during the alpha-phase was about 6.5 min while that in the beta-phase was about 230 min.

Animals↗
PubMed1977

The use of regression methods to study genotype-environment interactions: extending Griffing's model for diallel cross experiments and testing an empirical grouping method.

A model combining features of Griffing's diallel cross analysis with regression analysis for genotype-environment interactions is introduced using carp data of Moav et al. (1975) as an example. An analysis of variance based on this model provides information on the combining abilities of genetic effects and the interactions of these effects with environments from which inferences can readily be made on heterosis and heterosis-environment interactions. Applying the empirical grouping method of Lin and Thompson (1975) to these data (ignoring their diallel cross structure) established groups which were remarkably consistent with their members' crossing backgrounds.

Alleles↗
PubMed1977

Mechanism of isoproterenol-induced desensitization of tracheal smooth muscle.

Isolated rat tracheal smooth muscle became considerably less sensitive to the relaxing action of isoproterenol after being incubated with 5 x 10(-6) M isoproterenol for 30 minutes. Pretreatment of the tissue with propranolol, but not with methylprednisolone, clearly reduced the isoproterenol-induced desensitization. This suggested that propranolol by occupying the beta adrenergic receptor prevented isoproterenol from binding to this receptor, thereby preventing the isoproterenol-induced desensitization. Furthermore, an isoproterenol-desensitized tracheal preparation exhibited a diminished sensitivity to other beta agonists, but not to the spasmolytic actions of D600, hydralazine, sodium nitrite and aminophylline. These results suggested that the beta receptor is specifically involved in the desensitization induced by isoproterenol. A highly desensitized tissue could always be made to undergo complete relaxation by exposing it to sufficiently high concentrations of isoproterenol. Thus, there appeared to be no positive indication of a very large change in the apparent intrinsic activity of the isoproterenol in the desensitized tissue. However, the dissociation constant for the propranolol-beta receptor complex in the desensitized tissue was shown to be 180-fold larger than that in the normal tissue. These findings provide strong evidence that one demonstrable cellular change that occurs in the desensitized tissue is a pronounced reduction in the affinity of the beta receptors for isoproterenol.

Adrenergic beta-Agonists↗
PubMed1975

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

Efferent projections from the dorsomedial visual area (DM) in the owl monkey to other portions of visually responsive cortex were determined by degeneration and autoradiograhic methods of demonstrating axon pathways. The most prominent ipsilateral pathway was to posterior parietal cortex (PP) just medial to the terminal portion of the Sylvian fissure. Other ipsilateral projections were to subdivisions of the temporal lobe, the middle temporal visual area (MT) and the surrounding dorsolateral crescent (DL), to regions just rostral to area 18 on the medial wall of the cerebral hemisphere, and to the upper bank of the Sylvian fissure. The callosal projections of DM were to DM, PP, and MT of the opposite cerebral hemisphere. The results support the notion that visual association cortex consists of a number of separate, but complexly interrelated, subdivisions. The efferents to posterior parietal cortex suggest the possibility of an area for the integration of somatosensory and visual information.

Animals↗