Biomedical subjects

C L Shen

Publications and source records attributed to C L Shen.

At least 19 recordsLinked to original sources

PubMed1992

In vivo induction of apoptosis in immature thymocytes by staphylococcal enterotoxin B.

Staphylococcal enterotoxins are potent T cell mitogens. Recent studies have shown that the binding of these toxins to class II MHC molecules on accessory cells is essential for the stimulation of T cells which bear specific V beta segment of TCR. In the present study we show that i.v. administration of staphylococcal enterotoxin B (SEB) results in an enlargement of spleen and lymph nodes but causes thymus atrophy. Elimination of CD4+CD8+ cells predominantly accounted for the shrinkage of thymus, and the lowest level of this cell population was reached 4 days after SEB injection. Furthermore, this decrease in CD4+CD8+ cells was accompanied by a relative increase in the percentages of CD4+CD8-, CD4-CD8+ and CD4-CD8- cells, whereas their absolute numbers actually reduced on day 4. The thymus shrinkage involved apoptosis which was characterized by DNA fragmentation and morphologic changes. The depletion of Thy-1 high, TCR-alpha beta low and TCR-alpha beta intermediate cells also occurred with a kinetic correlated to the reduction of CD4+CD8+ cells. Our results further showed that the percentages of V beta 8+ cells reduced 12 h post SEB injection, increased after 2 days, and decreased again thereafter. SEB thus causes both apoptotic and stimulative effects in the thymus. Apparently, the tremendous loss of double-positive cells (greater than 90% in cell number on day 4) is not simply due to the reduction of V beta 8+ cells, the possible modulatory effect of other factors or hormones which may play a role in the cell death is discussed.

Animals↗

PubMed1992

Effects of toluene on the morphology of neuropeptide secretory neurons of the rat hypothalamus.

The effect of toluene on the hypothalamic hormone-secreting neurons and neurotransmitter-containing fibers in the rat was investigated by immunohistochemical methods. Multiple intraperitoneal injections of toluene (totally 7.5 ml) led to significant decreases of the neuronal numbers of vasopressin, oxytocin and neuropeptide Y in the preoptic and hypothalamic areas. The densities of vasopressin, oxytocin, norepinephrine and neuropeptide Y immunoreactive fibers of the toluene dose group decreased markedly in the median eminence. In contrast, LHRH neurons remained unchanged.

Animals↗

PubMed1992

A Taiwanese with a pair of sternalis muscles.

A pair of sternalis muscles have been found on both sides of the chest in an adult Taiwanese male. The muscles are located superficial to the medial part of the pectoralis major, arising from the sternum and are inserted into the sheaths of the rectus abdominis. They are innervated by the intercostal nerve. It should be emphasized that the sternalis muscle is rarely found in Taiwan.

Asian People↗

PubMed1991

The ovarian innervation in the dog: a preliminary study for the base for electro-acupuncture.

The origin of the canine ovarian sensory and sympathetic nerves was studied by applying horseradish peroxidase (HRP) or wheat germ agglutinin conjugated to HRP (WGA-HRP) to the ovarian stroma and into the ovarian bursa. HRP/WGA-HRP positive neurons were found bilaterally in the dorsal root ganglia of T10 to L4 segment with the majority located in T13 to L2. In sympathetic paravertebral ganglia, labeled neurons were distributed bilaterally in ganglia from T11 to L4 with the majorities located in segments T13 to L2. Both distributions show ipsilateral predominance. Labeled prevertebral neurons were mainly located in the aorticorenal ganglion, ovarian ganglia and caudal mesenteric ganglion. No labeled neurons were found in the dorsal motor nucleus of vagus, nodose ganglia or sacral segment from S1 to S3. This study provides the possible morphological basis of electro-acupuncture concerning the somato-visceral reflex of the ovary.

Animals↗

PubMed1991

Autoradiographic study of the retinal projections in the Chinese pangolin, Manis pentadactyla.

Autoradiography was used to investigate the optic system of the Chinese pangolin, Manis pentadactyla. The pattern of retinal projections in the Chinese pangolin is similar to that described in other mammals. Each retina projects bilaterally to the suprachiasmatic nucleus, dorsal and ventral lateral geniculate nuclei, pretectal area, and superior colliculus (SC). Only contralateral projections are found to the medial, lateral, and dorsal accessory optic nuclei. The large lateral nucleus receives a dense projection from the retina and forms a compact mass on the dorsolateral area of the cerebral peduncle. The lamination of the SC could not be clearly demonstrated in the brain of the Chinese pangolin.

Animals↗

PubMed1991

Innervation of the knee joint in the rabbit and the Formosan rock-monkey (Macaca cyclopis): a retrograde HRP study.

The number and segmental distribution of cell bodies of sensory afferents and sympathetic efferent innervating to the knee joint of the rabbit and the Formosan rock-monkey were investigated using retrograde transport with horseradish peroxidase (HRP). After injecting HRP into the articular knee joint capsule of the rabbits, labeled neurons were found in the ipsilateral L4-S2 dorsal root ganglia (DRG). However, following injection of HRP into the articular cavity of the knee joint in the rabbit and the monkey, labeled neurons were found in both the ipsilateral DRG (L5-S2 and L4-S1 of the rabbit and monkey, respectively) and in the ipsilateral sympathetic ganglia (SG) (L4-S3 (rabbit) and L3-S1 (monkey)). The majority of labeled neurons within the DRG and the SG were composed of medium and large neurons in the monkey and the rabbit, respectively. The present findings suggest that the sensory projections from and sympathetic projection to the knee joint in rabbits and monkeys are similar, but that both projections of monkeys were "shifted" one segment cranially compared to the rabbit on both projections.

Animals↗

PubMed1990

Decrease of catecholamine and neuropeptide Y-like immunoreactivity in the glycerol-induced acute renal failure of rats.

Changes of catecholamine and neuropeptide Y (NPY) were investigated in experimental acute renal failure (ARF) of rats. Concentrations of noradrenaline (NA) and dopamine (DA) were determined by chromatographic analysis using electrochemical detection. Renal content of NPY, identified by radioimmunoassay, was expressed as NPY-like immunoreactivity (NPY-LI). All animals with a plasma urea value higher than 200 mg/dl induced by injection of glycerol were employed as ARF subjects for the experiment. Formation of ARF was also confirmed by histological findings showing diffused necrosis of tubular epithelia. In ARF rats, renal contents of NA and DA decreased markedly (P less than 0.001), NA (ng/g wet tissue) decreased from 186.3 +/- 19.6 to 2.81 +/- 0.67 (n = 8), and DA (ng/g wet tissue) decreased from 14.69 +/- 4.97 to 4.05 +/- 2.66 (n = 8). Similarly, NPY-LI (pg/g wet tissue) in ARF was reduced significantly (P less than 0.001) from 435.23 +/- 35.82 to 4.61 +/- 0.52 (n = 8). The decrease of NA in ARF was obtained parallel to the change of NPY-LI; degeneration of adrenergic nerve fibers was confirmed by immunohistochemical observation. Results obtained suggest damage to the adrenergic and the dopaminergic innervation in the kidneys during ARF.

Acute Kidney Injury↗

PubMed1990

Inhibitory effect of octopamine on dopamine D-1 receptor in striatal homogenates of the rat.

In the striatal homogenates of rats, octopamine produced a dose-dependent inhibition of dopamine D-1 receptor both in the receptor binding of [3H]Sch-23390 and the formation of cyclic adenosine 3',5'-monophosphate (cyclic AMP) stimulated by dopamine in the presence of sulpiride. Failure of octopamine in the displacement of binding with [3H]N-0437, one of the radioligands for the dopamine D-2 receptor, indicated the specific selectivity of octopamine to dopamine D-1 receptor sites. Lack of effect on forskolin-stimulated formation of cyclic AMP ruled out the possible direct effect of octopamine on adenylate cyclase. These results suggest that octopamine possesses the ability to bind to striatal dopamine D-1 receptors of rats.

Adenylyl Cyclase Inhibitors↗

PubMed1990

Ontogeny of the FMRFamide-immunoreactivity in the rat forebrain and diencephalon.

Ontogeny of the FMRFamide (molluscan cardioexcitatory neuropeptide)-containing structures in the forebrain and diencephalon of the rat was investigated by employing immunohistochemical methods. FMRFamide-like immunoreacted (FMRF-IR) fibers first appeared in the borders of the periventricular zone and the preoptic area at embryonic day 18 (E18). Toward birth, the FMRF-IR fibers gradually increased both in immunoreactivity and in number in these areas. A pronounced increase in FMRF-IR was also found in the septum, the arcuate nucleus, the median eminence, the paraventricular nucleus and the amygdaloid complex. A few FMRF-IR fibers appeared at the prenatal stage in the caudate nucleus, the bed nucleus of the stria terminalis, the dorsomedial nucleus and the cortex. The first FMRFamide-immunoreactive neurons were seen in the caudate-putamen and the amygdaloid complex at E21. These FMRF-IR cells increased in immunoreactivity and a significant number of cells was noted in these nuclei in the adult rat. The highest density of FMRF-IR neurons, especially in the amygdala and tuberal hypothalamic area, was detected at postnatal two weeks (P15). FMRFamide-like immunoreactivity in the forebrain and diencephalon appeared in the cell fibers prior to that observed in the cell bodies. This may suggest that some of the immunoreacted fibers may have originated from the lower areas of the rat brain. High densities of FMRF-IR cells present in the embryonic and early postnatal stages may indicate that FMRFamide is an important factor involved in developmental organization of the central nervous system. These results also indicate a differential genesis of FMRF-IR neuronal groups in different regions.

Amino Acid Sequence↗

PubMed1989

4-Aminopyridine induces the release of neuropeptide Y (NPY) to produce an atropine- and tetrodotoxin-resistant contraction in rabbit isolated jejunum.

4-Aminopyridine (4-AP) induced an atropine- and tetrodotoxin (TTX)-insensitive contraction (resistant contraction), in a concentration-dependent manner, in the isolated jejunum of rabbits. The failure of specific antagonists of histamine, serotonin and substance P to affect this resistant contraction ruled out the participation of histamine, serotonin and/or substance P. Antiserum against neuropeptide Y (NPY) reduced this resistant contraction in a concentration-dependent manner and inhibited the action of 4-AP totally at a high concentration (1.25% dilution) whereas normal serum lacked this ability. This suggested that the release of NPY was involved in this 4-AP-induced resistant contraction. Radioimmunoassay of NPY-like immunoreactivity in isolated synaptosomal preparations indicated that 4-AP possessed the ability to induce the release of NPY. However, guanethidine did not affect the actions of 4-AP, indicating that NPY is released mainly from non-adrenergic nerves. Our results indicate that 4-AP induces the release of NPY from non-adrenergic nerves to produce an atropine- and TTX-resistant contraction in the isolated jejunum of rabbits.

4-Aminopyridine↗

PubMed1989

An antigen-specific hypersensitivity which does not fit into traditional classification of hypersensitivity.

A unique type of Ag-specific hypersensitivity was induced by challenging the Ag-sensitized mice at the ear. It was elicited within 1 h after the Ag challenge, and thus was distinct from either the delayed-type hypersensitivity (DTH) which developed in 24 h or the immune complex-mediated hypersensitivity which evolved in 4 to 6 h. This hypersensitivity was referred to as early-type hypersensitivity (ETH). The time required for these types of hypersensitivity to develop after immunization was also different; DTH required 4 to 6 days, ETH 9 to 11 days, whereas plasma protein-induced immune complex-mediated hypersensitivity needed 18 to 21 days. The ETH could be induced by a smaller amount of Ag than DTH, and unlike DTH could be transferred by either immune sera or T cell-derived culture factor which was small m.w. Although the ETH developed later than DTH after sensitization, it lasted longer once developed and the pattern of response was inversely related to DTH. Furthermore, the denatured hepatitis B surface Ag induced DTH but not ETH, in contrast to native hepatitis B surface Ag that induced both, suggesting that the epitopes recognized by TETH cells were distinct from those recognized by TDTH cells. The ETH could be induced by most Ag tested including poly(Glu60Ala10Tyr10, L-lactic dehydrogenase, insulin, chicken egg white lysozyme, polymerized human serum albumin, horse gamma-globulin, transferrin, fibrinogen, and plasminogen, but not by purified protein derivative. Because poly(Glu60Ala10Tyr10, L-lactic dehydrogenase, egg white lysozyme and insulin were under the Ir gene control and the inducibility of ETH was Ag dependent and was closely correlated with that of DTH, the expression of ETH also must be regulated by Ir gene. The histopathologic changes in ETH consisted of capillary congestion and edema. The vasopermeability was increased and there was the leakage of plasma proteins into the tissue. Based on these data, we concluded that the ETH reported in this study was a novel type of Ag-specific hypersensitivity.

Animals↗

PubMed1989

Distribution of serotonin immunoreactive neurons in the brainstem of the hamster, guinea pig, rabbit, and rat.

Immunohistochemical techniques were employed to study the distribution of serotonin (5-HT) immunoreactive neurons in the brainstem of the hamster, guinea pig, rabbit and rat. 5-HT neurons were principally found to be concentrated in the midline raphe nuclei, particularly, the raphe pallidus, raphe obscurus, raphe magnus, raphe median, raphe pontis and raphe dorsalis nuclei. Characteristically, these cell bodies are displayed in bands or wing-like patterns which extend laterally from the raphe into reticular formations. The formations often appear to blend with the catecholamine system. They are particularly evident in the brainstems of the rabbit and hamster which contain wider and more lateral extensions of the serotonergic (5-HT) neurons than those observed in the brainstems of the rat and guinea pig. The widespread distribution of 5-HT immunoreacted cell bodies in the brainstem shows that there are significant prospects of 5-HT in neuronal activities.

Animals↗

PubMed1989

Retinal projections to the medial terminal nucleus of the rat with induced unilateral congenital eye defects.

Retinal projections, particularly the ipsilateral projections, to the medial terminal nucleus (MTN) of the accessory optic system were investigated by autoradiography in adult rats after being reared in one of three different conditions: (1) normal visual experiences, (2) an application of trypan blue for intrauterine induction of congenital unilateral anophthalmia; and (3) the procedures for intrauterine production of congenital microphthalmia in which both eyes are reduced in size. In congenital monocular rats, there was an increase of uncrossed retinal projections to the MTN which does not normally exist. The expansion of the ipsilateral projection was markedly greater in the monocular rats than those inflicted with microphthalmia. The expansion may be due to the failure of the retraction of the ipsilateral retinal projections to the MTN and the collateral sprouting of optic fibers from the remaining eye.

Abnormalities, Drug-Induced↗

PubMed1988

The distribution of luteinizing hormone-releasing hormone (LHRH) neurons and fibers in the Formosan rock-monkey.

The anatomical distribution of neurons and fibers containing Luteinizing Hormone Releasing Hormone-Immunoreactivity (LHRH-IR) in the brain of the Formosan Rock-Monkey was investigated employing immunohistochemical techniques. LHRH-IR neurons were observed in an area demarcated rostrally by the diagonal band of Broca and caudally by the mammillary area. The majority of these neurons were principally localized in the preoptic area, periventricular zone, and the arcuate nucleus. The supraoptic nucleus, septal area, triangular septal nucleus, nucleus of the diagonal band of Broca, suprachiasmatic nucleus, retrochiasmatic area, mammillary area, and the amygdala also exhibited neuronal LHRH immunoreactivity. LHRH-IR fibers appeared to originate in all of the above areas of the hypothalamus, project caudally, and subsequently terminate in the median eminence (ME). In addition to the above, LHRH-IR fibers were also detected in the organum vasculosum of the lamina terminalis (OVLT). A scattering of LHRH-IR fibers were also observed in several extrahypothalamic regions, notably the subfornical organ, indusium griseum, habenular complex, septohypothalamic nucleus, and amygdala.

Animals↗

PubMed1988

Distribution of neurotensin-like immunoreactivity in the central nervous system of the Formosan monkey.

The distribution of neurotensin-like immunoreactivity was investigated in the central nervous system of the Formosan monkey employing immunohistochemical techniques. Neurotensin-containing cells were found to be widely distributed in the forebrain. The principal densities of neurotensin-like neuronal perikarya were located in the limbic system, the basal ganglion and the cerebral cortex; particularly in the amygdala, the septum, the neostriatum, the claustrum and the insula. The stria terminalis and the preoptic area were also rich in immunostained neurotensin-like neurons. A large number of immunoreactive fibers were observed from the cerebral cortex to the spinal cord in locations such as the median eminence, the arcuate nucleus, the hippocampus, the central gray and the dorsal horn of the spinal cord. We analyzed in detail the distribution of neurotensin-like immunoreactivity in the brain of the Formosan monkey, and compared these results with those obtained in the brain of the rat, Japanese monkey and human. Some possible implications regarding differences in location of this peptide are also briefly discussed.

Animals↗

PubMed1988

Retinal projections in the red belly squirrel (Callosciurus erythraeus Roberti): an autoradiographic study.

Tritiated labeled materials, [3H]proline and [3H]fucose, were used as tracers of the visual pathway by injection into the right eve of the red belly squirrel, After a designated survival period, the animals were sacrificed, and the brains were removed and processed using standard autoradiographic procedures. Sections were then examined under a microscope and some subcortical nuclei including the suprachiasmatic nucleus (SCN), dorsal and ventral lateral geniculate nuclei(dLGN and vLGN), three optic accessory nuclei (i.e., the medial, lateral and dorsal terminal nuclei - MTN, LTN and DTN), the nuclei of the pretectal area(PTN) and the superior colliculus(SC) in the subcortical regions were marked by labeled isotopes. Radioactive materials were found in the pulvinar nucleus(Pul), parabigeminal nucleus(PB) and dorsal lateral pontine gray(DLP). Some nuclei among the targets of retinal projection in the red belly squirrel received their projection bilaterally while others only did contralaterally. In addition, layered structures of the SC and LGN were clearly demonstrated in the brain of the red belly squirrel. Some differences in the optic system between the red belly squirrel and its near relative, the grey squirrel of North American, and other mammals are discussed.

Animals↗

PubMed1987

Characterization of the release of neuropeptide Y (NPY) induced by tyramine from synaptosomal preparations of rabbit jejunum.

The effect of tyramine on the secretion of neuropeptide Y-like immunoreactivity (NPY-LI) was investigated in a synaptosomal fraction prepared from rabbit jejunum. In addition to evoking the release of norepinephrine (NE), tyramine induced a dose-dependent increase of NPY-LI secretion which was insensitive to tetrodotoxin and was not affected by the removal of calcium ions from the bathing medium. Desipramine reduced the effectiveness of tyramine but did not influence the basal output of NPY-LI. There was a positive correlation between the inhibitory effect of desipramine on the NPY release and on the uptake of [14C]tyramine into synaptosomes. Guanethidine, however, at a concentration insufficient to block the uptake of tyramine reduced the release of both NE and NPY. These data suggest that tyramine enters into nerve terminals through a desipramine-sensitive mechanism, resulting in the co-release of NE and NPY which can be reduced by guanethidine.

Animals↗

PubMed1987

Release of neuropeptide Y (NPY) induced by tyramine in the isolated vas deferens of rat.

The effect of tyramine on the isolated vas deferens of rats was investigated. Tyramine induced a dose-dependent contraction which was blocked by phentolamine and disappeared in adrenergic denervated tissues. In the presence of an antiserum to neuropeptide Y (NPY), the contraction induced by concentrations of tyramine greater than 10 microM was markedly increased. In addition to inducing the release of 3H-norepinephrine (NE), tyramine evoked a concentration-dependent efflux of NPY-like immunoreactivity (NPY-LI) from synaptosomal preparations. This action was not modified either by the removal of calcium ion from the medium or by the pretreatment with tetrodotoxin (0.5 microM). Desipramine suppressed the NPY-LI release induced by tyramine apparently by the inhibition of the uptake of tyramine is suggested by the significant positive correlation between the reduction of 14C-tyramine uptake and the inhibition of NPY-LI release induced by desipramine (r = 0.946). Therefore, we suggest that tyramine does induce the release of NPY from rat vas deferens, in addition to effecting NE secretion.

Animals↗