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Biomedical subjects

C Shaw

Publications and source records attributed to C Shaw.

At least 181 records · Page 10Linked to original sources
PubMed1994

Cardiac involvement in seatbelt-related and direct sternal trauma: a prospective study and management implications.

The study set out to assess the incidence and consequences of pericardial and myocardial involvement in seatbelt-related sternal injury. Comparison was made with that from direct sternal trauma and implications for patient management were examined. The study was designed as a prospective sequential single centre study of 60 patients, from a total of 63 consecutive admissions over a 13 month period, admitted with blunt central chest trauma or multiple injuries involving the torso. Clinical status, correlated with echocardiographic, ECG and cardiac enzyme abnormalities were the main outcome measures. The study showed that 25% of 32 patients with seatbelt-related chest injury and 30% of 10 patients with multiple injuries had clinically unsuspected pericardial effusions detected by echocardiography. Pericardial effusion was not associated with an adverse outcome in the seatbelt-related injuries. Abnormalities of ECG or CK-MB isoenzyme levels were non-specific and did not correlate with the presence of pericardial effusion. From these data it is concluded that seatbelt-related sternal trauma is usually relatively benign. Echocardiography detects unsuspected pericardial effusion in a significant minority but ECG and cardiac enzyme estimations are of limited value. The routine admission to hospital of all patients with isolated seatbelt-related sternal trauma for cardiological monitoring is unnecessary. Inpatient treatment should be reserved for patients whose clinical condition, social circumstances or other injuries necessitate admission.

Accidents, Traffic↗
PubMed1994

The regional distribution of neuropeptides in human skin as assessed by radioimmunoassay and high-performance liquid chromatography.

In this study radioimmunoassay was used to determine neuropeptide levels in extracts from 17 differing anatomical regions of human skin. Marked regional variations of neuropeptide content for human skin were found and these variations are likely to reflect true physiological functions for the neuropeptides studied. In general the tachykinins, substance P (SP), neurokinin A (NKA) and calcitonin gene-related peptide (CGRP) were found in highest concentrations in regions of skin with the greatest tactile sensation. By contrast, highest concentrations of vasoactive intestinal peptide (VIP) and peptide histidine methionine (PHM) were found in axillary skin, where they probably play a part in axillary eccrine sweat production. Neurotensin was not found in any of the skin areas sampled, suggesting that it is relatively unimportant in human physiological skin control. Reverse-phase high-performance liquid chromatography (rpHPLC) was used to verify the results of radioimmunoassay. Both SP and NKA occurred in several regions in both their reduced and oxidized forms, as well as displaying molecular heterogeneity. CGRP occurred as one molecular species, this being alpha-CGRP, suggesting that this is the predominant molecular form in human skin. Likewise, both VIP and PHM displayed molecular homogeneity in the regions investigated by rpHPLC.

Adult↗
PubMed1994

Variable patterns of atrial natriuretic peptide secretion in man.

Peripheral circulating levels of atrial natriuretic peptide may exhibit short-term variation compatible with a pulsatile pattern of secretion. We obtained samples every 2 min for 90 min from the antecubital vein of 16 patients with chronic cardiac failure and 13 controls. Overall levels were higher in the patients (median and quartiles 230 (125,325) vs. 26 (16,48) ng l-1; P < 0.001). In both groups there was considerable variability, with 10 (2-12) peaks, 9 (7-15) troughs (both defined as > 2 SD from the mean) and 16 (13-18) pulses (defined by computer) during the sampling period in controls, and a similar number in patients. We then carried out simultaneous sampling in the pulmonary artery, femoral artery and peripheral vein in eight subjects with normal cardiac function and six patients with impaired function due to valvular heart disease. The pattern of variability was preserved in all three sites in both groups, suggesting intermittent secretion rather than variable breakdown of the peptide in the lung. No changes in right atrial pressure or heart rate were observed to coincide with the variations, but levels of the peptide in the pulmonary artery correlated with right atrial pressure in patients (r = 0.87; P < 0.05). The mechanism of such periodicity and its pathophysiological importance remain unknown.

Adult↗
PubMed1994

Colored aftereffects contingent upon global transformations?

Dodwell and Humphrey (Psychol. Rev. 97, 78-79, 1990) have argued that colored aftereffects (CAEs) are contingent on the global geometries of local orientation and edge components in induction patterns. The spatiotopic dimensions underlying these geometries are derived from previous applications of the mathematics of continuous transformations (Lie groups) to the stimulus dynamics of perceptual invariance. In these terms, complementary CAEs induced by inspecting alternating colored bullseyes and spokes are attributed to the adaptation of orthogonal spatiotopic channels; the former characterized by vectorfields dealing with object invariance under rotation, and the latter by vectorfields dealing with object invariance under dilation. Importantly, the pattern-contingent CAEs induced in this pair of pattern channels are independent of CAEs induced in channels characterized by vectorfields dealing with object invariance under vertical and horizontal translations (e.g. vertical and horizontal gratings). The present investigation examined whether CAEs contingent on the stimulus dynamics originally used to define these spatiotopic channels exhibit comparable properties. It is confirmed that pairs of complementary CAEs can be induced simultaneously with radially expanding and contracting bullseyes, and clockwise- and counter-clockwise-rotating spokes (Experiment 1); and it is shown that these CAEs combine linearly in generalizing to and from the radial and rotational components of spiral motion (Experiments 2 and 3 respectively). In direct contrast to findings for CAEs induced with stationary versions of these patterns, however, it is demonstrated that complementary pairs of CAEs induced by expanding and contracting bullseyes interact with CAEs induced by left- and right-moving vertical gratings, suggesting that the components of motion underlying these contingent effects are locally and not globally determined (Experiment 4).

Color Perception↗
PubMed1994

5-Hydroxytryptamine (serotonin)-immunoreactivity in the nervous system of Mesocestoides corti tetrathyridia (Cestoda: Cyclophyllidea).

An indirect immunocytochemical technique has been interfaced with confocal scanning laser microscopy to investigate the occurrence and distribution of serotoninergic (5-HT) nerve elements in Mesocestoides corti tetrathyridia. Cell bodies and nerve fibers immunoreactive to 5-HT were found concentrated in the innervation around the 4 suckers and associated commissures and in the 5 pairs of longitudinal nerve cords and their cross-connectives. Immunoreactivity was evident also in the extensive, peripheral network of fine fibers of the subtegumental region and in the plexus of varicose fibers that innervate the muscle in each of the suckers. In dividing stages of the tetrathyridium, the immunoreactive lateral nerve cords of adjoining progeny were in continuity around the base of the division cleft.

Animals↗
PubMed1993

The primary structure of pancreatic polypeptide from a primitive insectivorous mammal, the European hedgehog (Erinaceous europaeus).

Pancreatic polypeptide (PP) has been isolated from extracts of the pancreas of the European hedgehog (Erinaceous europaeus) which is a representative of the order Insectivora, deemed to be the most primitive group of placental mammals. Pancreatic tissues were extracted in acidified ethanol and the peptide was purified chromatographically using a PP C-terminal hexapeptide amide specific radioimmunoassay to monitor purification. Two major PP-immunoreactive peptides were baseline-resolved following the final analytical reverse phase HPLC fractionation. Each was separately subjected to plasma desorption mass spectroscopy (PDMS) and gas-phase sequencing. The molecular masses of each peptide were similar: (I) 4237.6 +/- 4 Da and (II) 4238.2 +/- 4 Da. The full primary structures of each peptide were deduced and these were identical: VPLEPVYPGDNATPEQMAHYAAELRRYINMLTRPRY. The peptides were deemed to be amidated due to their full molar cross-reactivity with the amide-requiring PP antiserum employed in radioimmunoassay. The molecular mass (4233.8 Da) calculated from the sequence was in close agreement with PDMS estimates and the reason for the different retention times of each peptide is unknown at present. Hedgehog PP exhibits only 2 unique amino acid substitutions, at positions 1 (Val) and 19 (His), when compared with other mammalian analogues.

Amino Acid Sequence↗
PubMed1993

Isolation and primary structure of a novel avian pancreatic polypeptide from five species of Eurasian crow.

Chicken pancreatic polypeptide is the prototype of the neuropeptide Y (NPY)/PP superfamily of regulatory peptides. This polypeptide was appended the descriptive term avian, despite the presence of some 8600 extant species of bird. Additional primary structures from other avian species, including turkey, goose and ostrich, would suggest that the primary structure of this polypeptide has been highly-conserved during avian evolution. Avian pancreatic polypeptides structurally-characterised to date have distinctive primary structural features unique to this vertebrate group including an N-terminal glycyl residue and a histidyl residue at position 34. The crow family, Corvidae, is representative of the order Passeriformes, generally regarded as the most evolutionarily recent and diverse avian taxon. Pancreatic polypeptide has been isolated from pancreatic tissues from five representative Eurasian species (the magpie, Pica pica; the jay, Garrulus glandarius; the hooded crow, Corvus corone; the rook, Corvus frugilegus; the jackdaw, Corvus monedula) and subjected to structural analyses. Mass spectroscopy estimated the molecular mass of each peptide as 4166 +/- 2 Da. The entire primary structures of 36 amino acid residue peptides were established in single gas-phase sequencing runs. The primary structures of pancreatic polypeptides from all species investigated were identical: APAQPAYPGDDAPVEDLLRFYNDLQQYLNVVTRPRY. The peptides were deemed to be amidated due to their full molar cross-reactivity with the amide-requiring PP antiserum employed. The molecular mass (4165.6 Da), calculated from the sequences, was in close agreement with mass spectroscopy estimates. The presence of an N-terminal alanyl residue and a prolyl residue at position 34 differentiates crow PP from counterparts in other avian species.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1993

Amyotrophic lateral sclerosis: quantitative autoradiography of [3H]MK-801/NMDA binding sites in spinal cord.

We have characterized a high-affinity binding site for [3H]MK-801, an NMDA receptor ion channel antagonist, in cervical spinal cords from patients who have died with amyotrophic lateral sclerosis (ALS) and from control subjects. In cervical spinal cord [3H]MK-801 labelled at least two binding sites, the highest affinity site having a Kd of between 9-16 nM. No significant differences in affinity were observed between spinal cords from ALS patients or controls. In spinal cords from ALS patients, large reductions in [3H]MK-801 receptor binding (between 30-40% reductions) were detected in both the dorsal and ventral horns. These data may reflect the death of receptor-bearing cells, or a form of receptor regulation.

Adult↗
PubMed1993

GNFFRFamide: a novel FMRFamide-immunoreactive peptide isolated from the sheep tapeworm, Moniezia expansa.

The widespread distribution of FMRFamide-immunoreactivity in platyhelminth nervous systems has been demonstrated immunocytochemically. Here we report the isolation and primary structure of the first platyhelminth FMRFamide-related peptide (FaRP) from the tapeworm, Moniezia expansa. The peptide was found to have a molecular mass of 785 Da and a primary structure of Gly-Asn-Phe-Phe-Arg- Phe-NH2 (GNFFRFamide). Acid alcohol extracts of this platyhelminth contained only this single FaRP which had a phenylalanyl (F) residue in the variable position 3 from the C-terminal occupied by either methionyl (M), leucyl (L) or isoleucyl (I) residues in most other FaRPs.

Amino Acid Sequence↗
PubMed1993

Neuropeptide Y and neuropeptide Y 3-36: isolation from human pancreatic endocrine tumours.

Using an antiserum raised to the C-terminal region of neuropeptide Y (NPY) which does not cross-react with pancreatic polypeptide (PP), immunoreactivity has been detected in two different endocrine tumours of the human pancreas in concentrations permitting isolation and structural analysis. In a clinically-typical gastrinoma, resected from the head of pancreas, the concentration of NPY immunoreactivity was 3.4 nmol/g. Reverse phase HPLC analysis of extracts of this tumour resolved a single immunoreactive peptide coeluting with synthetic human NPY. The molecular mass of the isolated peptide, determined by mass spectroscopy, was 4270 Da, which was in close agreement with that derived from the deduced primary structure of human tumour NPY (4271.7 Da), obtained by gas-phase sequencing. A somatostatinoma, resected from the region of the ampulla of Vater, contained 3.8 nmol/g of NPY immunoreactivity and isolation of this immunoreactive peptide followed by structural analyses, indicated a molecular structure consistent with NPY 3-36. These data suggest that NPY immunoreactivity detected in human pancreatic endocrine tumours is molecularly heterogenous, a finding which may be of relevance in the symptomatology of such tumours as attenuation of the N-terminus of this peptide generates receptor selectivity.

Adult↗
PubMed1993

Proteus syndrome with cardiomyopathy and a myocardial mass.

Proteus syndrome is an overgrowth syndrome principally affecting cutaneous and skeletal tissues, accompanied by subcutaneous hamartomas. We report on a patient with predominantly skeletal and visceral involvement, including a cardiac mass and thickening of the myocardial septum affecting cardiac conduction and contraction.

Adult↗
PubMed1993

Discussion paper: towards a systematic classification for regulatory peptides.

Advances in microsequencing technology have led to the elucidation of primary structures of peptidic messengers from many eukaryotic and prokaryotic life forms. Existing peptide nomenclature is based upon such factors as bioactivity, source of isolation (tissue or species), chemical attributes, acronyms derived from a combination of these factors, or by other arbitrary means. In order to overcome many of the problems arising from current nomenclature, a standardised classification scheme for peptidic messengers is proposed which utilises an alphanumeric code string analogous to EC enzyme classification to convey information on origin, chemistry and relatedness to other similar molecules. It is anticipated that the scheme outlined will provide the basis for the rational classification of new peptides.

Animals↗
PubMed1993

The effects of fornix and medial prefrontal lesions on delayed non-matching-to-sample by rats.

The present study compared the effects of fornix lesions and medial prefrontal lesions on a test of object recognition memory, delayed non-matching-to-sample. Neither lesion impaired the acquisition of this non-spatial test of working memory, indeed there was clear evidence that fornix damage resulted in improved non-matching performance during initial acquisition. This improvement in performance could be related to the loss of a spatial bias during the early stages of training. A series of experiments then systematically increased the familiarity of the stimuli (i.e. testing recency rather than recognition judgements). Neither the fornix nor the prefrontal lesions disrupted performance under these conditions, even though this manipulation affected nonmatching in a predictable manner. The same animals were also tested on a spatial forced-alternation task in a T-maze (spatial delayed non-matching-to-sample). The animals with fornix lesions performed at chance while the prefrontal animals were mildly, but significantly, impaired. The present findings are considered in the light of a number of seemingly contradictory findings regarding the effects of hippocampal system damage on nonspatial tests of recognition memory.

Animals↗
PubMed1993

An immunocytochemical study of putative neurotransmitters in the metacercariae of two strigeoid trematodes from rainbow trout (Oncorhynchus mykiss).

Whole mounts of the metacercariae of Diplostomum sp. and Cotylurus erraticus from rainbow trout have been treated cytochemically for the demonstration of cholinergic, serotoninergic (5-hydroxytryptamine) and peptidergic elements in the nervous system. Antisera directed against four vertebrate (pancreatic polypeptide, peptide YY, substance P and peptide histidine isoleucine) and two invertebrate peptides (neuropeptide F and FMRFamide) were used in an indirect immunofluorescence procedure in conjunction with confocal scanning laser microscopy (CSLM). Of the seven antisera tested, all except peptide histidine isoleucine showed significant immunoreactivity. Cholinergic and serotoninergic staining was found primarily in the central nervous system (CNS) and in cell bodies associated with the ventral and dorsal nerve cords in both trematodes. Peptidergic immunoreactivity was localised in the CNS and PNS of both genera, revealing an extensive innervation within the holdfast organ and in and around the oral and ventral suckers.

Animals↗
PubMed1993

Electron immunogold labeling of regulatory peptide immunoreactivity in the nervous system of Moniezia expansa (Cestoda: Cyclophyllidea).

An electron immunogold-labeling technique was used in conjunction with a post-embedding procedure to demonstrate for the first time the ultrastructural distribution of the parasitic platyhelminth neuropeptide, neuropeptide F (NPF), in the nervous system of the cestode Moniezia expansa. Two axon types, distinguished by their populations of different-sized electron-dense vesicles, were identified. Immunogold labeling demonstrated an apparent homogeneity of PP, FMRFamide and NPF (M. expansa) antigenic sites throughout the larger dense-cored vesicles within the central nervous system. Triple labeling clearly demonstrated the co-localisation of immunoreactivities (IR) for NPF, PP and FMRFamide within the same dense-cored vesicles. The presence of NPF-IR within the vesicles occupying the perikaryon of the neuronal cell body indicated that the peptides had undergone post-translational C-terminal amidation prior to entering the axon. Antigen pre-absorption experiments using NPF prevented labeling with either PP or FMRFamide antisera, and the failure of these antisera to block NPF-IR supports the view that some, if not all, of the PP/FMRFamide-IR is due to NPF-like peptides.

Animals↗
PubMed1993

Neuropeptide F-immunoreactivity in the tetrathyridium of Mesocestoides corti (Cestoda: Cyclophyllidea).

The distribution pattern and subcellular localisation of neuropeptide F (NPF) immunoreactivity (IR) in the tetrathyridium stage of Mesocestoides corti were investigated by whole-mount immunocytochemistry in conjunction with confocal scanning laser microscopy (CSLM) and by immunoelectron microscopy using immunogold labeling. Using an antiserum directed to the C-terminal decapeptide amide (residues 30-39) of synthetic NPF (Moniezia expansa), CSLM revealed NPF-IR throughout the central and peripheral nervous systems of parental and dividing tetrathyridia. Ultrastructurally, gold labeling of NPF-IR was confined to the contents of the smaller of the two sizes of electron-dense neuronal vesicle identified.

Animals↗