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Biomedical subjects

A Harvey

Publications and source records attributed to A Harvey.

At least 19 recordsLinked to original sources
PubMed1992

Isolation and characterization of a tobacco gene with homology to pectate lyase which is specifically expressed during microsporogenesis.

A genomic clone has been isolated which contains an open reading frame of 1191 bp interrupted by two small introns. The ORF has been sequenced and the transcriptional start determined. The predicted amino acid sequence shows homology to the deduced amino acid sequences of two pollen-specific pectate lyase genes identified in tomato. The genomic clone was isolated using a partial cDNA clone, TP10, which had been isolated from a Nicotiana tabacum pollen cDNA library by means of differential screening. TP10 has been fully sequenced and contains an open reading frame of 792 bp which shows 96% homology to the ORF in the genomic clone. The transcript corresponding to TP10 is maximally expressed late in pollen development, and has not been detected in vegetative tissues.

Amino Acid Sequence↗
PubMed1992

The relative contributions of histamine and prostanoids to bronchoconstriction provoked by isocapnic hyperventilation in asthma.

It has been proposed that exercise provokes bronchoconstriction in asthma by inducing mast cell degranulation, and that this occurs secondary to the hyperpnoea of exercise causing hypertonicity of the airway lining fluid. We investigated the contribution of the mast cell products, histamine and prostaglandins, to the bronchoconstriction induced by isocapnic hyperventilation (ISH) using single doses of terfenadine, a specific histamine H1-receptor antagonist, and flurbiprofen, a potent cyclooxygenase inhibitor. We also investigated the effect of flurbioprofen in single dose on bronchial histamine reactivity. Eleven asthmatics took part in a two phase, double-blind, randomized study. In phase 1, subjects attended on three occasions and received either terfenadine 180 mg, flurbiprofen 150 mg, or placebo, prior to 6 min of ISH. The mean maximum percentage fall in forced expiratory volume in one second (FEV1) induced by ISH was 31.5(+/- 3.2)% following placebo, 29.7(+/- 4.4)% following flurbiprofen (NS), and reduced to 16.6(+/- 3.7)% following terfenadine (p less than 0.01). In phase 2, subjects received bronchial challenge with histamine following either flurbiprofen 150 mg or placebo. No significant change in bronchial reactivity following flurbiprofen was seen. We conclude that as administered in this study, flurbiprofen has no effect on baseline bronchial reactivity to histamine. The inhibitory effect of terfenadine indicates that histamine, probably from airway mast cells, makes an important contribution to bronchoconstriction induced by isocapnic hyperventilation, whereas prostaglandin release has no significant role.

Adolescent↗
PubMed1991

Effects of morphine and naloxone upon the reactions of rats to a heat stressor.

Five experiments used rats to examine the conditioned hypoalgesia induced by exposure to a heated floor. Experiments 1 and 2 demonstrated that this hypoalgesia is mediated by non-opioid mechanisms of pain control, as evidenced by insensitivity to the opioid antagonist naloxone and by the absence of cross-tolerance with the opioid agonist morphine. Although non-opioid in nature, the acquisition of conditioned hypoalgesia was facilitated by naloxone and impaired by morphine (Experiments 3 and 4). These effects did not appear to be due to an opioid regulation of pain. (1) Pairing morphine with the heated floor attenuated acquisition in drug-tolerant rats. (2) This attenuation by morphine was removed when naloxone was given after exposure to the heated floor. (3) Conditioning was facilitated when naloxone was given after exposure to the heated floor (Experiment 5). The results were discussed in terms of an opioid regulation of (a) surprise, (b) arousal of an aversive motivational system, and (c) the affective component of pain.

Animals↗
PubMed1989

Possible involvement of chromosome 1 in in vitro immortalization: evidence from progression of a human adenoma-derived cell line in vitro.

We have previously reported that continuous in vitro passage in the presence of 3T3 feeders of a non-tumorigenic adenoma-derived epithelial cell line, designated PC/AA, resulted in its becoming immortal. At early passage PC/AA was normal diploid, whereas every cell of PC/AA late passage had an isochromosome 1(q) which led us to suggest that abnormalities of chromosome 1 may be involved in tumour progression. We now report the isolation of a 3T3-feeder-independent variant of early-passage PC/AA, designated PC/AA/FI, which was immortal in vitro and remained non-tumorigenic. Each cell of PC/AA/FI again has an isochromosome 1(q), like the late-passage PC/AA. However, with PC/AA/FI it is the other chromosome 1 of the homologous pair which is involved in the formation of the isochromosome 1(q). This is possible to determine because of the polymorphic centromeric heterochromatin on chromosome 1 of the early-passage PC/AA. With the late-passage PC/AA (grown with 3T3 feeders) the homologue with the large C-band has given rise to an isochromosome 1(q) whereas with PC/AA/FI it is the other homologue with the smaller C-band which has given rise to this isochromosome. Both the immortal PC/AA/FI and the immortal PC/AA late passage, therefore, have independent abnormalities involving chromosome 1. These results indicate that chromosome 1 may be involved in in vitro immortalization.

Adenoma↗
PubMed1986

Treatment of orbital pseudotumors and lymphoma.

Thirty-seven patients were identified in a retrospective review at Hahnemann University and Wills Eye Hospital; they had been treated for pseudotumor or lymphoma of the orbit and had adequate follow-up (x = 61.5 months). Overall, 31 of 37 patients (83.8%) were cleared of their orbital disease. Of the nine patients treated for lymphoma, all were cleared of disease in the orbit. Twenty-two of 28 patients (78.6%) with benign disease were likewise cleared of orbital disease. Ten of 10 patients who received radiation as their initial therapy were cleared. Overall, 17 of 20 (85%) of patients who received radiation as part of their therapy were cleared of orbital disease, with mean dosages of 2,166 cGy (1 cGy = 1 rad) for benign disease and 3,547 cGy for lymphoma. Brief representative case studies and a review of the literature are presented. Two patients with benign disease were cured of disease in the orbit but went on to develop systemic lymphoma. Radiation therapy plays an essential role in the management of patients with orbital lymphomatous diseases.

Adolescent↗
PubMed1985

Hiring smart.

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Humans↗
PubMed1975

Cyclic AMP and cyclic GMP: mediators of the mechanical effects on bone remodeling.

Compressive forces of physiological magnitude (60 grams per square centimeter) reduce the adenosine 3',5'-monophosphate and guanosine 3',5'-monophosphate content of the epiphyses of tibiae from 16-day-old chick embryos. An equivalent hydrostatic pressure applied directly to cells isolated from this tissue also affects cyclic nucleotide accumulation. The tissue response is uniform throughout the epiphysis, whereas the cell response varies according to the area of origin.

Animals↗
PubMed1975

A quantitative method for the application of compressive forces to bone in tissue culture.

A quantitative method for the application of compressive forces to long bones in culture is described. Using this method it was found that a physiological pressure of 80g/cm sq. applied to tibiae of 16-day-old chick embryos reduced glucose consumption to 50% of controls. Twenty four hours after the release of pressure glucose utilization again increased, approaching control levels. A pressure of 80 g/cm sq. also stimulated thymidine incorporation into DNA. The same pressure decreased the size of the extracellular fluid pool by 8%, but had no effect on the rate of equilibration of this pool with 22Na.

Animals↗