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Biomedical subjects

J Young

Publications and source records attributed to J Young.

At least 379 records · Page 21Linked to original sources
PubMed1989

The isolation and chemical characterization of a novel vasoactive intestinal peptide-related peptide from a teleost fish, the cod, Gadus morhua.

An octacosapeptide that shows sequence homology to porcine vasoactive intestinal peptide (VIP) has been isolated from a teleost fish, the cod, Gadus morhua. The full primary sequence is His-Ser-Asp-Ala-Val-Phe-Thr-Asp-Asn-Tyr-Ser-Arg-Phe-Arg-Lys-Gln-Met-Ala-Ala- Lys-Lys-Tyr-Leu-Asn-Ser-Val-Leu-Ala. This peptide contains four, or five substitutions, compared with dogfish and porcine VIP, respectively. The residues in positions 13, 26 and 28 are different in all three species. These substitutions seem to have little effect on bioactivity, since cod VIP was virtually equipotent with porcine VIP in stimulating amylase release from guinea-pig pancreatic acini. During the isolation procedure an N-terminally modified form of VIP (Des-His, or 2-28 cod VIP) was also isolated. The available data suggest the sequence of VIP is well conserved in vertebrates which is consistent with an important biological role.

Amino Acid Sequence↗
PubMed1989

Percutaneous feeding gastrostomy.

Percutaneous endoscopic gastrotomy tubes have been inserted in 50 patients with no mortality and minimal morbidity. The principal indications for their insertion were an inability to swallow (39 patients), a need for nutritional support (eight patients) and venting (three patients). The most common complication was peristomal wound infection (14 patients), the incidence of which was reduced significantly by the use of single-dose prophylactic antibiotic therapy. Percutaneous gastrostomies provide adequate nutrition with minimal morbidity in an acceptable way to both patients and those who care for them.

Adolescent↗
PubMed1989

The isolation and chemical characterization of phosphorylated enkephalin-containing peptides from bovine adrenal medulla.

There is increasing evidence that the opioid peptide precursor, proenkephalin A, and its products undergo extensive post-translational modification, in addition to the cleavage at dibasic amino acid sites. We have used an antiserum directed toward the C terminus of Met-enkephalin Arg6-Phe7 in a radioimmunoassay to monitor the purification to homogeneity of four peptide B variants from bovine adrenal medulla, using gel filtration, anion exchange chromatography, and reverse phase high performance liquid chromatography. Amino acid sequence analysis, together with immunochemical data, confirmed that each comprised the primary sequence, proenkephalin A-(209-239). In addition, three of the four variants were shown to be phosphorylated by alkaline phosphatase digestion, microphosphate analysis, and ethanethiol derivatization coupled with amino acid sequence analysis; these variants were shown to have 1, 2, or 3 phosphate groups per peptide chain, which corresponded to their increasing acidic nature. The phosphorylation sites were clustered together at positions Ser7, Ser13, and Ser15 and were in close association with acidic residues. The clustering of phosphorylated residues is unique among regulatory peptide precursors. This region of proenkephalin A is well conserved, which suggests that it constitutes an important novel functional domain.

Adrenal Medulla↗
PubMed1989

Quantitative measures of neurological function in chronic neuromuscular diseases and ataxia.

Interexaminer and intraexaminer reliability were determined for 30 quantitative measures of neurological function, including sensory threshold, tendon reflexes, maximum isometric strength, and timed tests and coded ratings of functional ability, in patients with Charcot-Marie-Tooth disease (n = 30), idiopathic polyneuropathy (n = 16) and spinocerebellar degeneration (n = 30). Five of 6 sensory and reflex measures had interexaminer reliability greater than 0.80 when the neurologists' examinations were 1 h apart; 2 of 7 achieved this level when the examinations were separated by 1 month. Interexaminer reliability between physical therapists was greater than 0.80 for 19 of 20 measures of strength and functional ability. Intraexaminer reliability coefficients greater than 0.80 were found for 13 of 24 sensory and reflex measures, 28 of 30 isometric strength measures, 24 of 30 timed tests and 5 of 6 coded ratings of functional ability. Electro-oculography, oral diadochokinetic syllable rates, hand and foot accelerometry, and tracings of sine and square waves were examined as quantitative indices of ataxia for patients with spinocerebellar degeneration. Of 11 measures of ataxia, only the oral diadochokinetic syllable rate test had acceptable reliability.

Activities of Daily Living↗
PubMed1989

Pregnenolone, dehydroepiandrosterone, and their sulfate and fatty acid esters in the rat brain.

The rat brain contains large amounts of pregnenolone (P) and dehydroepiandrosterone (D) arising from local biosynthetic pathways. We have devised a procedure for the measurement of both "neurosteroids" either unconjugated or released from their sulfate (S) or fatty acid (L) esters. The measurements were performed at the acrophase of the circadian variation of neurosteroids, and confirmed the large accumulation of P (25 +/- 8 ng/g, mean +/- SD) and of PS (19 +/- 6 ng/g) and DS (2.1 +/- 0.5 ng/g) in the brain of adult male rats. We found that fatty acid esters constitute the major species of neurosteroids in brain (PL 46 +/- 14, and DL 36 +/- 7 ng/g, in adult males). The levels of P and DS were increased by daily injection of vehicle to intact males, whereas castration, without or with testosterone or estradiol supplementation (2 mg daily for 7 days), did not produce a significant change of neurosteroids concentrations. Measurements of neurosteroids had not been previously reported in cyclic females. The levels of P, PL, and DS were identical in proestrous females and in intact males, whereas PS (26 +/- 6 ng/g) and DL (50 +/- 16 ng/g) were increased in females. Compared to proestrous females, diestrous females had lower levels of PS (19 +/- 6 ng/g), DS (1.7 +/- 0.4 ng/g), and PL (43 +/- 19 ng/g). These differences suggested a modulatory role of ovarian secretions on the metabolism of neurosteroids.

Animals↗
PubMed1989

The constitution and properties of phosphorylated and unphosphorylated C-terminal fragments of progastrin from dog and ferret antrum.

Antibodies to the extreme C-terminal tryptic (nona-) peptide fragment of porcine progastrin have been used in radioimmunoassay to identify progastrin fragments in dog, ferret and pig antral mucosa extracts and to monitor their purification. In addition to previously characterised phosphorylated and unphosphorylated C-terminal tryptic peptides of porcine progastrin a minor form corresponding to the C-terminal octapeptide (i.e. des-Ser C-terminal nonapeptide) was isolated and characterised. The latter form together with phosphorylated and unphosphorylated forms of the nonapeptides were also isolated and chemically characterised from dog antrum, and the unphosphorylated nonapeptide was characterised from ferret antrum. The primary amino acid sequences of the dog, ferret and pig nonapeptides were identical. In ferret the unphosphorylated nonapeptide predominated, and in dog the phosphorylated form predominated; in pig both forms of the nonapeptide were well represented. Intact progastrin was identified in gel filtration eluates of extracts of all 3 species, but occurred only in relatively low concentrations. The nonapeptides did not stimulate acid secretion in the conscious gastric fistula rat and they did not modify the acid response to G17. Phosphorylation of progastrin-derived peptides is evidently well conserved across a range of species even though there appear to be differences in the relative proportions of phosphorylated and unphosphorylated forms.

Animals↗
PubMed1989

Group process and social climate of GROW, a community mental health organisation.

GROW, a community based mutual-help organisation, aims to provide the means for those who have been mentally ill to rehabilitate themselves and grow personally. We measured psychiatric symptoms, group processes, social environment and perceived social support in a sample of GROW group members. We found that GROW does provide the opportunity for and encourages some personal changes and does provide social support. We could not draw any conclusions about GROW's efficacy as a rehabilitative agent.

Australia↗
PubMed1989

Monoclonal antibody and cytological detection of free malignant cells in the peritoneal cavity during resection of colorectal cancer--can monoclonal antibodies do better?

Detection of free malignant cells in the peritoneal cavity following curative resections of colorectal cancer may explain why some patients develop local or peritoneal recurrence after favourable operations. We have examined the incidence of peritoneal malignant cells using standard cytological methods and by indirect immunoperoxidase staining using monoclonal antibodies (CEA L11/285/14 and HMFG 1 and 2) in 30 patients having resection for colorectal cancer. Peritoneal washings were collected on opening the peritoneal cavity and immediately prior to closing the abdominal wall following resection. Abnormal cells were only demonstrated in 10 patients. Cytology revealed abnormal cells in seven patients (three preresection and three postresection, one patient had pre- and postresection positive cytology). Monoclonal antibody staining revealed abnormal cells in seven patients (two preresection and four postresection, one patient had both pre- and postresection positive stains). Only two patients had identical results using cytology and antibody staining. Seven of these 10 patients had hepatic metastases. The correlation between the assessment of free malignant cells using cytology and monoclonal antibody staining is poor. Long-term follow-up is required to see if 'free cells' have prognostic significance.

Adult↗
PubMed1989

A phase I trial of subcutaneously administered recombination tumor necrosis factor to patients with advanced malignancy.

Nineteen patients with advanced cancer for which there was no effective standard therapy or whose disease was refractory to standard therapy were treated with recombinant tumor necrosis factor (rTNF). The rTNF was administered subcutaneously for 5 consecutive days every other week for 3 treatment weeks. The doses administered ranged from 5 micrograms/m2/day to 150 micrograms/m2/day. There was no intrapatient dose escalation. Systemic side effects of chills, fever, hypotension, nausea, vomiting, and headache were mild and self-limiting. At the maximum tolerated dose of 150 micrograms/m2/day, five of seven patients experienced moderate to severe thrombocytopenia. Mild rapid declines in total leukocyte count occurred within 60-90 min of administration of the drug, followed by a rise in the total leukocyte count by 120 min. When the total daily dose was administered in a single subcutaneous site, skin ulceration and necrosis occurred at the 100 micrograms/m2/day dose. By giving the total daily dose in two subcutaneous sites, the maximum tolerated dose increased to 150 micrograms/m2/day, and there was no further skin ulceration or necrosis. Skin necrosis occurred in the abdomen and thigh but not on the upper extremity at the 100 micrograms/m2/day dose given in a single site. There was no other significant organ toxicity. No rTNF was detectable in the serum even at the highest doses. No antibodies to TNF developed in any of the patients. The recommended dose of rTNF for Phase II trials given for 5 days subcutaneously is 150 micrograms/m2/day divided into two or more sites.

Adult↗
PubMed1988

The human gastrin precursor. Characterization of phosphorylated forms and fragments.

There is a potential phosphorylation site in the C-terminal region of the precursor for the acid-stimulating hormone gastrin, which is immediately adjacent to an important cleavage point. In the present study we have sought to identify, separate, quantify and characterize phosphorylated and unphosphorylated forms of human progastrin and its fragments. Identification was made by two radioimmunoassays: (a) a novel assay employing an antibody raised to intact human progastrin; and (b) an assay using antibody reacting with the C-terminal tryptic fragment of human progastrin, as well as progastrin itself. Two forms of human progastrin isolated from a gastrinoma were separated by ion-exchange h.p.l.c., and had similar elution positions on reverse-phase h.p.l.c. and on gel filtration. The more acidic peptide contained close to equimolar amounts of phosphate. On trypsinization, peptides were released that co-eluted on ion-exchange h.p.l.c. with, and had the immunochemical properties of, naturally occurring C-terminal fragments of progastrin. One of the latter was isolated and shown by Edman degradation after derivatization with ethanethiol to have the sequence Ser (P)-Ala-Glu-Asp-Glu-Asn. Similar peptides occur in antral mucosa resected from ulcer patients. The unphosphorylated forms of progastrin predominated, whereas the phosphorylated forms of the C-terminal fragments were predominant. This distribution could be explained by preferential cleavage of phosphorylated progastrin. We conclude that in human progastrin, Ser-96 can occur in the phosphorylated form; this residue immediately follows a pair of basic residues (Arg-Arg) that are cleaved during synthesis of the biologically active product.

Amino Acid Sequence↗