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J Elliott

Publications and source records attributed to J Elliott.

At least 163 records · Page 9Linked to original sources
PubMed1994

Characterisation of mu-opioid receptors on SH-SY5Y cells using naloxonazine and beta-funaltrexamine.

The irreversible opioid receptor antagonists naloxonazine and beta-funaltrexamine have been used to determine whether multiple mu-opioid receptors exist on undifferentiated SH-SY5Y human neuroblastoma cells. Naloxonazine binds irreversibly to the mu 1-opioid receptor subtype and reversibly to the mu 2-opioid receptor subtype. On SH-SY5Y cells naloxonazine afforded a Ki of 3.4 +/- 0.7 nM, and was fully reversible, indicating the mu-opioid receptor population on SH-SY5Y cells was solely of the mu 2-opioid receptor subtype. The alkylating agent beta-funaltrexamine was maximally able to alkylate only 60% of the mu-opioid receptor sites on SH-SY5Y cells, labelled with [3H]diprenorphine or [3H][D-Ala2,MePhe4,Gly(ol)5]enkephalin (DAMGO). The reversible binding of naloxonazine and the insensitivity of a percentage of the mu-opioid receptor sites to alkylation by beta-funaltrexamine suggests that differences do exist in the mu 2-opioid receptor population on undifferentiated SH-SY5Y cells. This may indicate further heterogeneity or the inability of beta-funaltrexamine to alkylate all relevant nucleophilic groups in a single population of receptors.

Amino Acid Sequence↗
PubMed1994

A 170 kDa polypeptide from mung bean shares multiple epitopes with rabbit skeletal myosin and binds ADP-agarose.

A 170 kDa polypeptide that has been partially purified from mung beans is retained by ADP-agarose even in the absence of divalent cations when most non-myosin ATPases and kinases do not bind. Attempts to demonstrate a myosin-like ATPase activity were inconclusive, however, and the protein accounts at most for only a small part of the total K+ EDTA ATPase activity of mung bean extracts. All four monoclonal antibodies raised to the 170 kDa polypeptide react with rabbit skeletal muscle myosin and localize the 170 kDa polypeptide in mung bean root tip cells to the actin-containing phragmoplast and to sites dispersed throughout the cytoplasm which probably include some but not all actin cables. These 4 monoclonals and 3 commercially available antimyosin monoclonals all recognise rabbit skeletal myosin and 160-170 kDa proteins that are present in two other angiosperms tested. In addition, a 158 kDa protein of mung bean reacts with only one antibody and does not bind ADP-agarose. We conclude that strong but not yet conclusive evidence points to the 160-170 kDa proteins of angiosperms being a widely conserved form of myosin heavy chain.

Adenosine Diphosphate↗
PubMed1994

Effect of sequential treatment with prostaglandin F2 alpha and/or oxytocin on estrus and pregnancy rate of lactating dairy cows.

A total of 335 lactating dairy cows was used to determine the effect of oxytocin or PGF2a given 8 h after treatment with a luteolytic dosage of PGF2a on the percentage of cows exhibiting estrus within 7 d after treatment, and the pregnancy rate to a single insemination at this time. On the initial day of treatment (Day 0), cows with a palpable corpus luteum on the ovary were treated with 25 mg, im of PGF2a. At 8 h later, the cows were divided into 3 groups. Cows in Group 1 (n = 112) were treated with oxytocin (0.33 IU/kg bwt im); cows in Group 2 (n = 112) were treated with 25 mg, im of PGF2a; and cows in Group 3 (n = 111) served as the untreated controls. Cows in all 3 groups were continuously observed for estrus visually or by way of an activated heatmount detector within 7 d after treatment, and were inseminated within 12 h of the observed estrus.Plasma progesterone (P4) concentration was determined using radioimmunoassay on Day 0 and Day 2. Of the cows with P4 greater than 1 ng/ml on Day 0, the percentage of cows observed in estrus within 7 d after treatment was 75, 89 and 72% for cows in Group 1, Group 2 and Group 3, respectively. When all cows were evaluated, the percentage of cows observed in estrus within 7 d after treatment was 60, 70 and 55% for cows in Group 1, Group 2 and Group 3, respectively. In both instances, the value for cows in Group 2 was significantly higher than that for either cows in Group 1 or Group 3. The pregnancy rate for cows inseminated within 7 d was similar for cows in all 3 groups. The results of this study demonstrated that treatment of dairy cows with 2 luteolytic dosages of PGF2a at an 8-h interval resulted in more cows being observed in estrus within 7 d than with 1 treatment with PGF2a, or with oxytocin given at an 8-h interval after a luteolytic dosage of PGF2a.

Journal Article↗
PubMed1994

Antinociceptive and toxic effects of (+)-epibatidine oxalate attributable to nicotinic agonist activity.

1. Epibatidine is an analgesic substance, isolated from the skin of the poisonous frog Epipedobates tricolor, for which the mechanism of action was previously unknown. 2. The IC50 of synthetic (+)-epibatidine oxalate (the naturally occurring isomer) for [3H]-nicotine binding to rat whole-brain membranes was 0.1 nM. The (-)-isomer also exhibited high affinity (IC50 = 0.2 nM). 3. (+)- and (-)-Epibatidine exhibited much lower affinity for displacement of the muscarinic ligand [3H]-N-methylscopolamine binding to rat cortical membranes (Kapp = 6.9 microM and 16.0 microM respectively). The (+)-enantiomer of epibatidine had an antagonist/agonist (NMS/oxo-M) binding ratio of 4.2 This is consistent with a muscarinic antagonist profile. 4. (+)-Epibatidine oxalate (10 microM) did not cause significant (> 30%) displacement of radioligand binding to opioid, excitatory amino acid, benzodiazepine, 5-HT, dopamine, adrenaline or peptide receptors. 5. (+)- and (-)-Epibatidine (5-20 micrograms kg-1 s.c.) doubled response latency in the mouse hot-plate test. Antinociception and behavioural depression induced by (+)-epibatidine (5 micrograms kg-1) was fully blocked by the nicotinic antagonists mecamylamine (2 mg kg-1 s.c.) or dihydro-beta-erythroidine (2 mg kg-1 s.c.). The muscarinic antagonist scopolamine (0.4 and 10 mg kg-1 s.c.) caused partial reversal of antinociception induced by (+)-epibatidine in mice, but not in rats. 6. These findings demonstrate that (+)-epibatidine oxalate salt is a highly selective and potent nicotinic analgesic agent.

Analgesics↗
PubMed1994

The role of nitric oxide in the responses of equine digital veins to vasodilator and vasoconstrictor agents.

Isolated equine digital veins were examined in vitro to study the importance of the endothelium in the responses to both vasodilator and vasoconstrictor agents and to characterise the endothelial-derived mediators involved. Carbachol (Cch; 1 microM) and bradykinin (Bk; 1 nM) caused relaxation of U44069-induced tone by 79.5 +/- 0.35% and 73.7 +/- 4.0% respectively. Mechanical removal of the endothelium completely prevented relaxant responses to Cch and to Bk showing they were mediated by the endothelium. Treatment of veins with NG-nitro-L-arginine methyl ester (L-NAME; 30 and 300 microM) inhibited vasorelaxant responses to both Cch and Bk whereas the cyclooxygenase inhibitor, ibuprofen (10 microM) had no inhibitory effect. The inhibitory action of L-NAME on the relaxations produced by Cch was partly reversed by L-arginine (3 and 10 mM). Cch-relaxations were potentiated in the presence of super oxide dismutase (15 units/ml) and inhibited by methylene blue (10 microM). The vasorelaxant effects of ATP (0.01 microM to 0.1 mM) were not dependent on the presence of the endothelium and the selective P2y receptor agonist, 2-methylthio-ATP proved to be ineffective as a vasodilator. Removal of the endothelium did not enhance the vasoconstrictor effects of the alpha 1 adrenoceptor agonist phenylephrine (0.01 microM to 0.1 mM) and treatment with L-NAME (300 microM) did not change the vasoconstrictor responses to 5-HT (1 nM to 10 microM) or the alpha 2 adrenoceptor agonist BHT-920 (1 nM to 1 microM).(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Triphosphate↗
PubMed1994

Effect of hormonal treatment on fertility in dairy cows with dystocia or retained fetal membranes at parturition.

Holstein cows (n = 445) that had experienced dystocia, retained fetal membrane, or both at parturition were used to determine the effects of GnRH, PGF2 alpha, or both on various reproductive measurements. Cows affected with these conditions were assigned randomly to each of four treatment groups. One group of cows was untreated, and three groups received GnRH once at 12 d postpartum, or GnRH at 12 plus PGF2 alpha at 26 d postpartum, or PGF2 alpha given at 12 and 26 d postpartum. Another group of 191 cows that calved normally were untreated. Conception rate after first AI was higher for cows treated with PGF2 alpha at 12 and 26 d postpartum. Cows affected with dystocia, retained fetal membranes, or both and treated early postparum with GnRH alone or followed 14 d later with PGF2 alpha did not have improved reproductive performance. Cows calving during the summer months of June through September experienced a reduction in the reproductive traits examined.

Animals↗
PubMed1994

Cell fractionation in non-ionic detergent distinguishes sub-populations of polyoma virus middle T antigen and reveals a novel form.

The transforming function of polyoma virus, middle T antigen (MT), interacts with several cellular enzymes, essential to its oncogenic activity. We have used cell fractionation to study the various MT/cellular protein complexes. We demonstrate that MT can be separated into three sub-species, dependent upon extraction in two buffers that we designate A and B: Antigen extracted from whole cells by both buffers (called MT1) is associated with most of the phosphorylated phosphatidyl-inositol kinase 85 kD subunit, pp85, and protein phosphatase 2A. Antigen (MT2), associated with the greater portion of pp60c-src, is extracted by buffer B, but not buffer A. A third population (MT3), resistant to extraction by either buffer, is not detectably associated with protein phosphatase 2A or pp85. It is, however, associated with a low level kinase activity. The interaction between pp60c-src and MT appears to influence the formation of both MT2 and MT3. MT2 fractionates with the cellular microtubule network, but does not appear to be directly associated with it. MT3, a previously undescribed population, comprises about one third of MT in wild type antigen-containing cells. It is missing in mutants incapable of interacting with pp60c-src, but exists in the absence of an interaction with pp85. We suggest that MT3 may be an intermediate in, or product of, one of the MT/pp60c-src signalling pathways, distinct from that involving pp85.

Animals↗
PubMed1993

Attitudes and practice of New Zealand doctors in the management of patients with dyslipidaemia.

AIMS: To assess current attitudes and clinical practice of New Zealand doctors in the management of dyslipidaemia. METHODS: Questionnaires were sent to all New Zealand general practitioners, fellows of the Royal Australasian College of Physicians and members of the Cardiac Society. Questions were asked about the present status of plasma lipids as risk factors for coronary heart disease, screening practices, thresholds for dietary and drug intervention and the cost-effectiveness of interventions. RESULTS: A total of 1798 replies were analysed, an effective response rate of 64%. Eighty-six percent were from general practitioners. Cholesterol is regarded as an independent risk factor for coronary heart disease by 88% (95% CI 86-89) of general practitioners, 94% (86-98) of general physicians and 98% (88-100) of cardiologists. High-density lipoprotein cholesterol is regarded as an independent risk factor less by general practitioners (68% (66-70)) than general physicians (87% (76-94)) or cardiologists (89% (76-96)), p < 0.001. Over 80% of doctors believe that reducing cholesterol levels will reduce cardiac death, myocardial infarction and the progression of coronary heart disease. However, in practice only 25% measure lipids in all their adult patients, 92% measure lipids in patients with symptomatic coronary heart disease, 86% in patients with hypertension and 60% in smokers, while 73% percent of doctors have measured their own cholesterol. Whereas 86% thought the population diet should be modified, 71% of doctors would not give dietary advice to asymptomatic patients unless the fasting cholesterol was > 6.5 mmol/L. The reduction in cholesterol achieved by a low fat diet was thought to be < 10% by 68% of responders. Fifty percent of doctors refer less than a quarter of their patients to dietitians although 83% stated that they had ready access to a publicly-funded dietitian. There is wide variation in thresholds for intervention in patients with symptomatic coronary heart disease. The median threshold for dietary intervention was 5.2-6.5 mmol/L, and for drug therapy, 6.6-7 mmol/L among physicians. Eight percent of doctors believe patients > 75 years of age should be treated for dyslipidaemia with drugs. Over half could not answer questions about the relative cost-effectiveness of lipid-modifying drug therapy. CONCLUSIONS: Most New Zealand doctors believe there is an independent relationship between plasma lipid levels and coronary heart disease. In practice, screening is selective and there is wide variation in thresholds for dietary and drug intervention.

Attitude of Health Personnel↗
PubMed1993

"Infectious" transplantation tolerance.

The maintenance of transplantation tolerance induced in adult mice after short-term treatment with nonlytic monoclonal antibodies to CD4 and CD8 was investigated. CD4+ T cells from tolerant mice disabled naïve lymphocytes so that they too could not reject the graft. The naïve lymphocytes that had been so disabled also became tolerant and, in turn, developed the capacity to specifically disable other naïve lymphocytes. This process of "infectious" tolerance explains why no further immunosuppression was needed to maintain long-term transplantation tolerance.

Animals↗
PubMed1993

Association of phenotypic and genotypic characteristics of invasive Streptococcus pyogenes isolates with clinical components of streptococcal toxic shock syndrome.

Sixty-two invasive Streptococcus pyogenes strains, including 32 strains isolated from patients with streptococcal toxic shock syndrome (STSS), were analyzed for the following phenotypic and genotypic characteristics: M-protein type, serum opacity factor production, protease production, the presence of streptococcal pyrogenic exotoxin (Spe) genes A, B, and C, and in vitro production of SpeA and SpeB. These characteristics were analyzed for possible associations with each other as well as with clinical components of STSS. M-type 1, the most commonly isolated M-type, was significantly associated with protease production. Protease activity was significantly associated with the clinical sign of soft tissue necrosis. M-type 1 and 3 strains from STSS patients were significantly associated with the clinical signs of shock and organ involvement as well as with SpeA production in vitro. Finally, the production of SpeA was significantly associated with the clinical component of shock and organ involvement as well as with rash. These data suggest that STSS does not make up a single syndrome but, rather, that the multiple STSS clinical criteria probably reflect different phenotypic characteristics of individual S. pyogenes isolates.

Adolescent↗
PubMed1993

A case of deletion 14(q22.1-->q22.3) associated with anophthalmia and pituitary abnormalities.

An interstitial deletion of the region q22.1-->q22.3 of chromosome 14 is described in a child with bilateral anophthalmia, dysmorphic features including micrognathia, small tongue, and high arched palate, developmental and growth retardation, undescended testes with a micropenis, and hypothyroidism. Interstitial deletions of the long arm of chromosome 14 are extremely rare, but this case seems to confirm that the region q22 is specifically concerned with pituitary and eye development.

Abnormalities, Multiple↗
PubMed1993

Positive and negative selection in transgenic mice expressing a T-cell receptor specific for influenza nucleoprotein and endogenous superantigen.

A transgenic mouse was generated expressing on most (> 80%) of thymocytes and peripheral T cells a T-cell receptor isolated from a cytotoxic T-cell clone (F5). This clone is CD8+ and recognizes alpha alpha 366-374 of the nucleoprotein (NP 366-374) of influenza virus (A/NT/60/68), in the context of Class I MHC Db (Townsend et al., 1986). The receptor utilizes the V beta 11 and V alpha 4 gene segments for the beta chain and alpha chain, respectively (Palmer et al., 1989). The usage of V beta 11 makes this TcR reactive to Class II IE molecules and an endogenous ligand recently identified as a product of the endogenous mammary tumour viruses (Mtv) 8, 9, and 11 (Dyson et al., 1991). Here we report the development of F5 transgenic T cells and their function in mice of the appropriate MHC (C57BL/10 H-2b, IE-) or in mice expressing Class II MHC IE (e.g., CBA/Ca H-2k and BALB/c H-2d) and the endogenous Mtv ligands. Positive selection of CD8+ T cells expressing the V beta 11 is seen in C57BL/10 transgenic mice (H-2b). Peripheral T cells from these mice are capable of killing target cells in an antigen-dependent manner after a period of in vitro culture with IL-2. In the presence of Class II MHC IE molecules and the endogenous Mtv ligand, most of the single-positive cells carrying the transgenic T-cell receptor are absent in the thymus. Unexpectedly, CD8+ peripheral T-cells in these (H-2k or H-2d) F5 mice are predominantly V beta 11 positive and also have the capacity to kill targets in an antigen-dependent manner. This is true even following backcrossing of the F5 TcR transgene to H-2d scid/scid mice, in which functional rearrangement of endogenous TcR alpha- and beta-chain genes is impaired.

Animals↗
PubMed1993

Automated production of high density cosmid and YAC colony filters using a robotic workstation.

We report here on a system for automated preparation of high-density colony filters of arrayed libraries using the high density replicating system (HDR) for the Beckman Biomek 1000 robotic workstation. This system, consisting of a 96-pin tool, a sterilization station and controlling software, transfers samples from microplates onto target membranes in arrays up to 36 times the density of a 96-well microplate. The transfer operation can be completely automated with the addition of the Biomek Side Loader System, which consists of a robotic arm capable of transferring plates and filters between the Biomek working tablet and a storage area. Using the complete system, we are able to plate 32 replica filters (8 x 12 cm), each containing the clones from 16 different microplates (i.e., 1536 clones per filter), in a 16-h overnight run without any operator intervention. We describe conditions used for transfer of bacterial yeast colonies and fixation of DNA to the membranes, and we illustrate hybridization results obtained with cosmid and YAC filters.

Biotechnology↗
PubMed1992

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Persons with Disabilities↗
PubMed1992

Amine oxidase enzymes of sheep blood vessels and blood plasma: a comparison of their properties.

1. A comparison between the biochemical properties of semicarbazide-sensitive amine oxidase (SSAO) activities has been made in sheep blood plasma and arterial wall. 2. The metabolism of benzylamine (BZ) by blood plasma was resolved into high affinity (Km 2.76 +/- 0.24 microM) and low affinity (Km 743 +/- 49 microM) activities. Spermidine metabolism was by a single component (Km 174 +/- 22 microM) and this amine reduced the metabolism of high concentrations of BZ. 3. A single component metabolised BZ in arterial homogenates (Km 11.3 +/- 1.3 microM) and which metabolised spermidine at a very slow rate. 4. Dopamine was deaminated by plasma SSAO and competed with both low and high concentrations of BZ. Dopamine also interfered with arterial metabolism of BZ. 5. These results suggest that there are two SSAO enzymes in sheep blood plasma, with one having similar properties to SSAO in the arterial wall.

Animals↗