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Biomedical subjects

G B Irvine

Publications and source records attributed to G B Irvine.

At least 37 records · Page 2Linked to original sources
PubMed1994

Immunocytochemical distribution of neuropeptide F (NPF) in the gastropod mollusc, Helix aspersa, and in several other invertebrates.

The distribution of neuropeptide F (NPF) immunoreactivity in the snail, Helix aspersa, has been demonstrated by immunocytochemistry using 2 region-specific antisera. One, designated NPF3, was raised against a synthetic N-terminal fragment of Helix aspersa NPF; the other, designated PP221, was raised against the C-terminal hexapeptide amide of mammalian pancreatic polypeptide (PP) but cross-reacts fully with the analogous C-terminal region of Helix aspersa NPF. The distribution of NPF immunoreactivity has also been compared with that of FMRFamide using alternate serial sections of Helix aspersa ganglia. Results showed that NPF immunoreactivity was abundant and widespread in the central and peripheral nervous systems and the pattern of immunostaining obtained using both region-specific antisera was similar. Likewise, immunocytochemistry of neural tissues of a congeneric species, Helix pomatia, and 2 prosobranch gastropods, Buccinum undatum and Littorina littorea, produced similar staining patterns with both antisera. However, in the cephalopod mollusc, Loligo vulgaris, and the cestode, Moniezia expansa, positive immunostaining was only obtained with the C-terminal PP antiserum. Immunostaining of alternate serial sections of Helix aspersa ganglia with NPF3, and an antiserum raised to FMRFamide, showed that while a few neurones were immunoreactive with one antiserum only, in the majority, both immunoreactivities were co-localised. NPF thus appears to be an important neuropeptide of widespread distribution in Helix aspersa and the differential immunocytochemical staining obtained using the 2 region-specific antisera would suggest a high degree of primary structural conservation within the gastropod molluscs, but lack of conservation of the N-terminal region of the peptide in other invertebrate groups.

Amino Acid Sequence↗
PubMed1994

Immunocytochemical localization of neuropeptide F-immunoreactivity in the circumoesophageal ganglia of the gastropod mollusc, Helix aspersa using electron microscopy.

Neuropeptide F (NPF)-immunoreactivity has been localized by electron microscopy in the central nervous system of the gastropod mollusc, Helix aspersa using a region-specific antiserum in conjunction with post-embedding immunogold labelling. The specific antiserum employed, designated NPF3, was raised to a synthetic N-terminal fragment of H. aspersa NPF. Gold-labelling revealed that NPF-immunoreactivity was found almost exclusively over the contents of dense-cored secretory vesicles within nerve axons in both cerebral and subesophageal ganglia. Double-labelling of NPF and FMRFamide demonstrated no apparent co-localization in the paired cerebral ganglia. Instead, immunoreactivities of the two neuropeptides were found to have distinct locations within the ganglia. These findings suggest that NPF may be an important neuroregulator in H. aspersa and that in the cerebral ganglia it may be anatomically-distinct from FMRFamide and related peptides.

Amino Acid Sequence↗
PubMed1994

Biological activity and receptor binding properties of some analogues of pQDPFLRFamide.

To investigate the role of the N-terminal region of the heptapeptide FMRFamide-like peptide, pQDPFLRFamide, three analogues were synthesized. The analogues [pQNPFLRFamide, pQDAibFLRFamide (Aib = aminoisobutyric acid) and pQDGFLRFamide] contained modifications at amino acid residues 2 and 3, which we believed might be critical for maintaining the bioactive conformation of the heptapeptide. The analogues were tested for their ability to bind to receptors in membranes from Helix aspersa circumoesophageal ganglia and for their biological effects on the isolated Helix heart, the Helix tentacle retractor muscle, and extensor-tibiae neuromuscular preparation of the locust. Schistocerca gregaria. The substitution of Asn for Asp2 and that of Aib for Pro3 were conservative with respect to retention of heptapeptide-like biological activity, whereas the substitution of Gly for Pro3 significantly improved the binding affinity of the peptide for the FMRFamide receptors and conferred on the peptide some characteristic FMRFamide-like biological activity. Thus, pQDPFLRFamide bioactivity may depend on a bent conformation in solution.

Amino Acid Sequence↗
PubMed1994

Biological activity and receptor binding properties of some C-terminally modified analogues of FMRFamide.

The functional role of the C-terminal amide group (-CONH2) of the molluscan regulatory peptide FMRFamide has been examined in two sets of analogues based on FnLKFamide and FnLRFamide (nL = norleucine). In each series the amide group was replaced by -CONHCH3, -CON(CH3)2, -CONHNH2, -COOCH3, -CH2OH, and -COOH. The analogues were tested for their ability to bind to receptors in membranes from Helix aspersa circumoesophageal ganglia and for their biological effects on the isolated Helix heart. The results indicate i) that agonist activity, but not binding to the receptor, requires the presence of the amide carbonyl group; ii) the hydrogen atoms of the amide group are not essential either for binding or for agonist activity (the mono- and dimethylamides were more effective than the parent compounds on both counts); iii) the is more effective an agonist than is the amide in stimulating Helix heart.

Animals↗
PubMed1992

Serum neurone-specific enolase levels in patients with neuroendocrine and carcinoid tumours.

We have examined concentrations of neurone-specific enolase (NSE) in sera from 18 patients with various neuroendocrine tumours, 26 patients with carcinoid tumours, 21 patients with non-neuroendocrine tumours and 37 control individuals. No statistically significant difference between the concentrations in patients with neuroendocrine tumours and patients with carcinoid tumours was found. However the NSE concentrations in patients with carcinoid and neuroendocrine tumours, when these two groups were combined, were significantly different from the patients with non-neuroendocrine tumours or the control individuals (P < or = 0.01). 38.5% of the patients with carcinoid tumours had raised NSE concentrations in serum; 55.5% of those with non carcinoid neuroendocrine tumours had raised concentrations. There appeared to be no correlation between the NSE concentrations and the extent of metastases.

Adult↗
PubMed1992

The primary structure of neuropeptide F (NPF) from the garden snail, Helix aspersa.

Neuropeptide F (NPF), originally isolated from the sheep tapeworm, Moniezia expansa, consists of 39 amino acid residues terminating in a phenylalaninamide. An analogous neuropeptide has been isolated and sequenced from extracts of circumoesophageal ganglia of the garden snail, Helix aspersa. This neuropeptide exhibits partial primary structural similarity to members of the vertebrate neuropeptide Y (NPY)/pancreatic polypeptide (PP) superfamily. NPF is thus of widespread occurrence in the nervous systems of invertebrates from different phyla and may represent the phylogenetic precursor of the vertebrate NPY/PP superfamily.

Amino Acid Sequence↗
PubMed1992

Immunochemical characterisation of tachykinin immunoreactivity in the nervous system of the garden snail, Helix aspersa.

1. Circumoesophageal ganglia and foot muscle of the garden snail, Helix aspersa, were subjected to immunocytochemistry using antisera to the tachykinins, substance P (SP), neurokinin A (NKA), kassinin (KAS) and eledoisin (ELE). 2. Immunoreactivity in neuronal somata and fibres was detected only with the SP antiserum. 3. SP and NKA radioimmunoassays were performed on extracts of circumoesophageal ganglia. In common with immunocytochemistry, immunoreactivity was only detected with the SP antiserum. 4. Gel permeation chromatography of extracts resolved a single peak of immunoreactivity eluting slightly later than synthetic mammalian SP. Reverse-phase HPLC of immunoreactive fractions resolved two immunoreactive peptides representing oxidised and reduced forms of a single peptide. 5. These data suggest that the nervous system of H. aspersa contains a single tachykinin with C-terminal structural characteristics similar to mammalian SP.

Amino Acid Sequence↗
PubMed1992

The natural history of the meniscus in anterior cruciate insufficiency. Arthroscopic analysis.

We studied arthroscopically the meniscal pathology in 100 patients with functional instability of the knee from isolated rupture of the anterior cruciate ligament at an average time of three years after injury. Meniscal tears were observed in 86 patients and multiple lesions of both menisci were common. An incomplete longitudinal cleavage, visible on both surfaces of the posterior horn, was seen in more than half the knees and seemed to indicate progressive meniscal deterioration. Clinical examination was unreliable and we suggest that arthroscopic assessment is necessary for accurate diagnosis and staging.

Adolescent↗
PubMed1991

Aminopeptidase activities present in tissues of Helix aspersa.

1. Tissues of Helix aspersa have been examined for the presence of aminopeptidase activities. 2. Enzyme activities were detected using synthetic peptide substrates containing the fluorescent leaving group 7-amino-4-methyl coumarin. The methods used included continuous fluorimetric assay and activity staining of enzymes in non-denaturing polyacrylamide gels. 3. Several types of peptidase activity were detected, including three distinct aminopeptidases which differ in molecular size and substrate preference.

Amino Acid Sequence↗