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Biomedical subjects

C Shaw

Publications and source records attributed to C Shaw.

At least 271 records · Page 15Linked to original sources
PubMed1990

An ontogenetic study of the cholinergic and serotoninergic nervous systems in Trilocularia acanthiaevulgaris (Cestoda, Tetraphyllidea).

The localisation and distribution of the cholinergic and serotoninergic components of the nervous system in the plerocercoid, adult and free proglottis stages of the tetraphyllidean tapeworm Trilocularia acanthiavulgaris were determined by enzyme histochemical and immunocytochemical techniques. The central nerve ring (CNR) in the scolex contains two lateral ganglia and gives rise to five pairs of longitudinal nerve cords (LNC's; three lateral, two median). The nerve cords run posteriorly throughout the bodies of the plerocercoid and adult worms and the free proglottis. Nerves from the CNR and accessory lateral LNC's pass to the bothridia, where they give rise to extensive nerve plexuses. As the individual proglottides develop along the strobila, a small nerve ring forms at the anterior end of each proglottis; within the nerve ring, distinct bilateral ganglia develop prior to the release of the proglottis. All ten LNC's are present in the free proglottis. The genital atrium and cirrus sac are innervated by cholinergic and serotoninergic elements. The cholinergic nervous system predominates in the CNS within the scolex, whereas there is a larger population of 5-HT-immunoreactive nerve cells associated with the LNC's and segmental ganglia along the strobila and within the free proglottis.

Animals↗
PubMed1990

Peptidergic nerve elements in three developmental stages of the tetraphyllidean tapeworm Trilocularia acanthiaevulgaris. An immunocytochemical study.

The localization and distribution of seven neuropeptides in the nervous system of the plerocercoid, adult and free proglottis stages of the tetraphyllidean tapeworm Trilocularia acanthiaevulgaris have been determined by an indirect immunofluorescence technique. Six of the peptides are vertebrate-derived, namely, pancreatic polypeptide (PP), peptide tyrosine tyrosine (PYY), vasoactive intestinal polypeptide (VIP), peptide histidine isoleucine (PHI), substance P (SP) and somatostatin (SRIF); the seventh is the invertebrate neuropeptide, FMR Famide. This is the first demonstration of VIP and SP immunoreactivity in a cestode parasite, and for SRIF this is its first description in any parasitic platyhelminth. Cell bodies and nerve fibres immunoreactive to PP, PYY, VIP, SP and FMRFamide are present throughout the CNS; the distributions of PHI and SRIF were more restricted. In the PNS, nerve fibres immunoreactive to PP occur in the bothridia, whilst in the free proglottis nerve fibres immunoreactive to PYY and VIP innervate the gonads; VIP-immunoreactive nerve elements also supply the reproductive ducts. Extra-neuronal sitings of peptide immunoreactivities were evident for PHI, in association with the excretory system, and for SRIF, in presumed tegumental cell bodies in the free proglottis. The results are discussed in relation to the possible roles of the peptides in the neurophysiology and developmental biology of the worm.

Animals↗
PubMed1990

Occurrence and distribution of putative neurotransmitters in the frog-lung parasite Haplometra cylindracea (Trematoda: Digenea).

The localisation and distribution of the cholinergic, serotoninergic and peptidergic components of the nervous system of the frog-lung fluke Haplometra cylindracea have been determined by the application of standard enzyme cytochemical and immunocytochemical techniques to cryostat sections and whole-mount preparations. Cholinesterase activity (ChE), as indicative of acetylcholine, has been demonstrated cytochemically in the CNS and PNS; however, the anterior ganglia were notably unreactive. The occurrence of serotonin was examined by an indirect immunofluorescence technique, and immunoreactivity (IR) was demonstrable in small, paired anterior ganglia and in fine nerve fibres associated with the somatic muscle, cirrus and gonopore. The peptidergic portion of the nervous system was investigated using antisera to 17 mammalian regulatory peptides and the invertebrate peptide FMRFamide, and was visualised by both indirect immunofluorescence and confocal scanning laser microscopy. Positive immunostaining occurred with antisera raised against pancreatic polypeptide (PP), peptide tyrosine tyrosine (PYY), substance P (SP), peptide histidine isoleucine (PHI) and FMRFamide. Immunoreactivity to PP, PYY and FMRFamide was widespread throughout the nervous system and was evident in large, paired anterior ganglia, the dorsal commissure, main nerve tracts and the extensive array of small fibres that constitute the PNS. In contrast, the distribution of nerves immunoreactive to SP and PHI was less apparent, with PHI-IR occurring exclusively within the fibrous neuropile of the ganglia and in fibres of the ventral nerve cord. Results are discussed with respect to the distribution of the various neurochemical elements and their roles as putative neurotransmitters and/or regulatory molecules.

Animals↗
PubMed1990

A cytochemical study of the serotoninergic, cholinergic and peptidergic components of the reproductive system in the monogenean parasite, Diclidophora merlangi.

The reproductive system of the monogenean gill parasite, Diclidophora merlangi, was examined for the presence of cholinergic, serotoninergic and peptidergic innervation using cytochemical and immunocytochemical techniques. Cholinesterase activity and 5-hydroxytryptamine immunoreactivity (5-HT-IR) were confined to neural elements of the male reproductive system, being evident in the innervation of the cirrus, whereas only 5-HT was present in nerves and somata of the elongate seminal vesicle. Peptidergic innervation was localised to both the male and female reproductive systems of the worm. Within the female reproductive apparatus pancreatic polypeptide, peptide tyrosine tyrosine, neuropeptide Y, substance P, neurokinin A, eledoisin, FMRFamide and gastrin/cholecystokinin immunoreactive fibres and somata were observed in the oviduct, vitelline reservoir and ovovitelline duct. Intense peptide immunoreactivity was identified in fibres in the wall of the ootype and in a surrounding population (greater than 100) of somata that were situated beyond Mehlis' gland cells and all of which were connected to the ootype wall by fine cytoplasmic connectives. The strategic location of this peptidergic cell population infers its involvement in the egg-forming sequence in this platyhelminth parasite.

Animals↗
PubMed1990

Hymenolepis diminuta: intestinal goblet cell response to infection in male C57 mice.

Intestinal goblet cell numbers in two regions of the small intestine (20-30% and 60-70% distance form the pylorus) of male, 6- to 8-week-old C57 mice have been monitored following a 5-cysticercoid infection of the rat tapeworm, Hymenolepis diminuta. Test and sham-infected control mice were autopsied 0, 4, 8, 10, 14, and 28 days postprimary infection (p-1 degree-i) and 2, 4, 5, 7, and 14 days postsecondary infection (p-2 degree-i), administered 28 days p-1 degree-i. Results show a statistically significant increase in the number of mucus-containing goblet cells in both regions of the intestine during primary and secondary infections. Peak goblet cell numbers occurred on Day 8 p-1 degree-i and Day 5 p-2 degree-i in the 20-30% region and on Day 10 p-1 degree-i and Day 5 p-2 degree-i in the 60-70% region. In both regions, cell numbers declined to control levels by Day 14 p-1 degree-i, but remained significantly above control values 14 days p-2 degree-i. The increase in cell numbers correlated with an increase in goblet cell theca size and observable amounts of luminal mucus. The same infection regime in mice treated with cortisone elicited no goblet cell response. Male Wistar rats given a 10-cysticercoid infection and autopsied on Day 0, Day 10, and 15 months p-i showed a statistically significant increase in mucus-containing goblet cells only in the 60-70% region of intestine 10 days p-i; however, the worm burden was not eliminated. The functional significance of these results is discussed in relation to host immunity and murine cestode rejection.

Animals↗
PubMed1990

Cross-modal matching by amnesic subjects.

The present study examined the performance of two groups of amnesic subjects on a cross-modal identification task. It was found that subjects with Korsakoff's disease did not differ from alcoholic controls on their ability to match the tactile feel of an arc with the visual appearance of the full circle from which the arc was taken. The postencephalitic subjects were, however, impaired on this same task. All groups performed normally on two intramodal control tasks. The postencephalitic group, like the Korsakoff subjects, were also poor at identifying common objects from tactile cues. The results are consistent with the notion that limbic regions in the temporal lobe are important for cross-modal associations.

Adult↗
PubMed1990

Cholecystokinin octapeptide reduces ethanol intake in food- and water-sated rats.

The putative satiety peptide cholecystokinin octapeptide (CCK-8) has been shown to reduce ethanol intake induced by prior fluid deprivation. Since fluid-deprived animals tend to reduce their food intake and consequently become hungry, the ability of CCK-8 to reduce ethanol intake might be limited to conditions where the motivation for food and fluid are accentuated. The present study assessed this possibility by examining the effect of peripheral injections of CCK-8 on voluntary ethanol intake fostered by the limited access procedure which uses food- and water-sated rats. Under these conditions CCK-8 still produced a dose-dependent decrease in ethanol intake. These results demonstrate that CCK-8 reduces ethanol intake even in the absence of hunger and thirst drives.

Alcohol Drinking↗
PubMed1990

Characterisation of xenopsin immunoreactivity derived from pepsinised human skin and possible mechanism of in vivo generation.

Human skin was subjected to a variety of extraction and enzymatic digestion procedures. Extracts and digests were subjected to neurotensin and xenopsin radioimmunoassays of known specificity. No neurotensin immunoreactivity was detected in any preparation with any region-specific antiserum. C-terminal xenopsin immunoreactivity was present in skin homogenates following incubation with both soluble and solid-phase pepsin and in those incubated with a leucocyte lysate or purified cathepsin D. The generation of xenopsin immunoreactivity was dependent on low pH and enzymes of pepsin-type specificity acting on a tissue precursor of approximately 30 kDa. Gel permeation chromatography of skin-derived xenopsin immunoreactivity identified a single molecular species larger than synthetic xenopsin which was resolved into two components by reverse-phase HPLC with retention times similar to synthetic xenopsin and kinetensin. Human skin thus contains a high-molecular-weight precursor protein and an endogenous acid protease, cathepsin D, capable of generating a peptide of similar size and C-terminal structure to amphibian xenopsin under acidic conditions such as might occur locally in wounds or at sites of inflammation.

Chromatography, Gel↗
PubMed1990

Regulatory peptides in parasitic platyhelminths.

Regulatory peptides are short chains of amino acids that regulate cell-to-cell interactions in widely divergent animal groups. Evidence is accumulating to suggest that they mediate many aspects of physiology and behaviour, serving as neurotransmitters, neuromodulators and hormones. While most data in this field derive from studies on the mammalian nervous and endocrine systems, the last decade has witnessed an upsurge of interest in invertebrate peptide biology, not least because it is likely that many regulatory peptides originated in the nervous system of invertebrates. Platyhelminths, like other invertebrate groups investigated, contain numerous neuropeptides, and here David Halton and colleagues review the evidence that these putative signalling agents serve key roles in parasite motility, reproduction and morphogenesis. The physicochemical differences between host and parasite peptides raise the possibility that selective disruption of peptidergic control systems in parasites could be an exploitable target in future chemotherapeutic strategies.

Journal Article↗
PubMed1990

Mammalian regulatory peptide immunoreactivity in the trematode parasite Haplometra cylindracea and the lung of its frog host, Rana temporaria: comparative chromatographic characterisation using reverse-phase high-performance liquid chromatography.

1. Extracts of Haplometra cylindracea and lung tissues of its host, Rana temporaria, were subjected to radioimmunoassay using antisera to nine mammalian regulatory peptides. 2. In these extracts, immunoreactivity was measured to pancreatic polypeptide, substance P, neurokinin A, gastrin-releasing peptide and glucagon. The levels of each peptide varied considerably with some marked differences between those demonstrable in parasite and host (notably pancreatic polypeptide). 3. Reverse-phase HPLC fractionation of extracts revealed general chemical differences between parasite and host peptides, with some peptides present in more than one molecular form.

Animals↗
PubMed1990

Characterisation of neurotensin-immunoreactivity in porcine ileum using region-specific radioimmunoassays and chromatographic fractionation: isolation and primary structure of porcine neurotensin.

1. Neurotensin-immunoreactivity has been characterised in porcine ileum using region-specific radioimmunoassay coupled to chromatographic fractionation. 2. Two immunoreactive peptides were identified. 3. Peptide 1 was immunochemically, chromatographically and structurally identical to bovine neurotensin. 4. Peptide 2 exhibited novel immunochemical and chromatographic characteristics and represents a new neurotensin-related peptide.

Amino Acid Sequence↗
PubMed1990

Tachykinin immunoreactivity in the European common frog, Rana temporaria: localization, quantification and chromatographic characterization.

1. Tachykinin immunoreactivity has been localized, quantified and chromatographically-characterized in the brain, stomach, intestine and skin of Rana temporaria. 2. Antisera to mammalian substance P (SP) and neurokinin A (NKA) immunostained nerve fibres in all tissues except skin, and a population of mucosal endocrine cells in the intestinal epithelium. 3. Radioimmunoassay of tissue extracts identified SP immunoreactivity in all tissues but NKA immunoreactivity was restricted to the brain. 4. Chromatographic analysis of both frog tachykinins revealed that they possessed different physico-chemical properties than their mammalian counterparts.

Amino Acid Sequence↗
PubMed1990

Concurrent and sequential pattern discrimination learning by patients with Korsakoff amnesia.

Patients with Korsakoff's syndrome and alcoholic controls learned to discriminate sets of pairs of patterns presented concurrently, in order to test predictions based on monkeys' performance in similar tasks following medial temporal or diencephalic lesions. In Experiment 1 the subjects learned a 2-pair, a 6-pair and a 10-pair set; the Korsakoff group were impaired on the first and last, but not on the second set. In Experiment 2, the same subjects learned single pairs sequentially, and 2-pair and 8-pair sets concurrently. The effect of 2 types of feedback for correct responses (visual or non-visual) was also compared. The Korsakoff patients were markedly poorer than controls under all conditions; the type of feedback made little difference. In several respects the patients' impairment differed from what had been predicted from the animal experiments.

Alcohol Amnestic Disorder↗
PubMed1990

The serotoninergic, cholinergic and peptidergic components of the nervous system in the monogenean parasite, Diclidophora merlangi: a cytochemical study.

Confocal scanning laser microscopy has been employed with immunocytochemical techniques to map the distribution of serotoninergic and peptidergic components in the nervous system of the monogenean gill-parasite, Diclidophora merlangi; results are compared with the distribution of cholinergic components, following histochemical staining for cholinesterase activity. While all three neurochemical elements are present in the central and peripheral nervous systems, the cholinergic and peptidergic systems dominate the CNS, whereas the PNS has a majority of serotoninergic nerve fibres. The cholinergic and peptidergic neuronal pathways overlap extensively in staining patterns, suggesting possible co-localization of acetylcholine and neuropeptides. Within the peptidergic nervous system, immunoreactivity to the pancreatic polypeptide family of peptides and FMRFamide were the most prevalent. Gastrin/cholecystokinin (CCK)-, neuropeptide Y-, substance P-, neurokinin A- and eledoisin-like immunoreactivities have been demonstrated for the first time in a monogenean parasite. The gastrin/CCK- and tachykinin-like immunoreactivities had an apparently restricted distribution in the worm.

Acetylcholinesterase↗
PubMed1990

A confocal scanning laser microscope study of the peptidergic and serotoninergic components of the nervous system in larval Schistosoma mansoni.

The localization and distribution of the serotoninergic and peptidergic elements of the nervous system of larval Schistosoma mansoni have been investigated using an indirect immunofluorescence technique in conjunction with confocal scanning laser microscopy (CSLM). A range of antisera was used, raised to the biogenic amine, 5-hydroxytryptamine (5-HT, or serotonin), the vertebrate peptides pancreatic polypeptide (PP), peptide YY (PYY) and neuropeptide Y (NPY) and to the native invertebrate peptide, FMRFamide; all these antisera were shown previously to be immunopositive in the adult worm. No immunoreactivity to 5-HT was detected in any of the larval stages, but both miracidia and cercariae were consistently immunoreactive to all 4 peptides. The peptidergic nervous system of the miracidium is relatively simple, taking the form of a central neural mass with associated paired anterior and posterior nerve tracts. The cercarial peptidergic nervous system comprises a central commissure joining paired anterior ganglia, from which emanate paired dorsal and ventral nerve tracts, which terminate at the body/tail junction. The excretory bladder region of the tail is also immunoreactive for the 4 peptides, and a fine pair of nerve tracts extends the length of the tail shaft. Immunoreactive nerve cell bodies are also evident in the midbody region of the intrasprocystic cercariae, these same structures being immunoreactive for the neuronal marker, neurone-specific enolase (NSE). The organization of the larval peptidergic nervous system is compared to that of the cholinergic nervous system and contrasted with the peptidergic system in the adult worm. The absence of immunoreactivity to 5-HT is discussed in relation to the proposed development of the aminergic nervous system upon establishment in the definitive host.

Animals↗
PubMed1990

Hymenolepis diminuta: changes in intestinal morphology and the enterochromaffin cell population associated with infection in male C57 mice.

Mean villus height, crypt depth and the number of 5-HT-positive enterochromaffin (EC) cells have been examined in two regions of the small intestine (20-30% and 60-70% distance from the pylorus) of male, 6 to 8-week-old, C57 mice following a 5-cysticercoid infection of the rat tapeworm, Hymenolepis diminuta. Test mice and sham-infected controls were autopsied 0, 4, 8, 10, 14 and 28 days post-primary infection (p-1 degree-i) and 2, 4, 5, 7 and 14 days post-secondary infection (p-2 degrees-i), administered 28 days p-1 degree-i. Morphometric analysis revealed a statistically significant increase in crypt depth in the 60-70% intestine region in infected mice during both primary and secondary infections; no significant deviation from the control was observed for villus height in infected mice. Statistical analysis showed a significant increase in the number of 5-HT-positive EC cells in infected mice. This response occurred in the lower portion of the intestine on days 10-p-1 degree-i and 5-p-2 degrees-i, and was not due to increased mucosal surface area in this region. Results are discussed with reference to murine cestode rejection and the possible involvement therein of the neuroendocrine system.

Animals↗