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Biomedical subjects

M Collins

Publications and source records attributed to M Collins.

At least 361 records · Page 20Linked to original sources
PubMed1970

Alkaloids from catecholamines in adrenal tissue: possible role in alcoholism.

Epinephrine and norepinephrine condensed with acetaldehyde or with formaldehyde in dilute aqueous solution at neutral pH and room temperature to form 1,2,3,4-tetrahydroiso-quinoline alkaloids. Similar condensation reactions occurred in cow adrenal glands perfused with dilute aldehyde solutions at 37 degrees C. Biosynthesis of these alkaloids in vivo could play a role in altering an individual's behavior during and after the ingestion of alcohol.

Acetaldehyde↗
PubMedDate not supplied

Comparison of bicistronic retroviral vectors containing internal ribosome entry sites (IRES) using expression of human interleukin-12 (IL-12) as a readout.

BACKGROUND: Many gene therapy applications require the co-ordinated delivery of more than one reading frame. We wished to systematically compare IRES in the context of a retroviral vector to determine which was the most effective for protein production and viral titre. To do this we monitored expression of IL-12, as co-ordinated expression of both p35 and p40 subunits is required for production of the active heterodimer. METHODS: Retroviral vectors were constructed to express human IL-12 in which an IRES initiates translation of the p40 subunit, with the IRES optimally aligned to the initiation codon of p40. Vectors containing an IRES from either polio virus (PV), encephalomyocarditis virus (EMCV), foot and mouth disease virus (FMDV) or murine leukaemia virus (MLV) were compared with a vector expressing IL-12 as a single protein (Flexi-12; in which the two IL-12 subunits are linked by a peptide). RESULTS: All vectors produced high titre virus and directed synthesis of IL-12 in target cells. The bicistronic vectors containing the IRES from EMCV and PV were the most effective in infected 3T3 cells, producing up to 40 ng IL-12/10(6) cells/48 h, similar to the 50 ng IL-12/10(6) cells/48 h obtained with Flexi-12. The IRES from PV was the most efficient in human melanoma cells. CONCLUSIONS: Bicistronic retroviral vectors have been constructed that effectively transduce target cells and produce high levels of protein. Target cell specificity of IRES function was observed. The combination of Flexi-12 and the IRES from PV will be useful in the generation of vectors expressing IL-12 with a second protein such as IL-2 for transduction of melanoma cells.

Aphthovirus↗
PubMedDate not supplied

The use of denaturing gradient gel electrophoresis to screen for DNA sequence polymorphisms in the human factor VIII gene.

We describe the use of denaturing gradient gel electrophoresis to screen for DNA sequence polymorphisms in the human factor VIII gene. DNA fragments that differ in sequence by only a single base pair can be separated on denaturing gradient gels due to changes in their melting behavior. Previous studies have demonstrated the use of denaturing gradient gels to detect sequence changes in human genomic DNA, including mutations in the beta globin gene and polymorphisms on chromosome 20. We have begun to use denaturing gradient gels to look for polymorphisms within the human factor VIII gene. The DNA sequences of seven cloned fragments from introns in the human factor VIII gene were determined and used to predict a melting map for each fragment. The melting behavior of each cloned fragment was evaluated by electrophoresis into denaturing gradient gels. Appropriate fragments were then used as radioactive probes for hybridization to human DNA samples that had been digested with restriction enzymes. Heteroduplexes formed between the probe and genomic DNA samples were electrophoresed into denaturing gradient gels. The final positions of heteroduplex bands were determined by autoradiography. We describe a general approach for using denaturing gradient gel electrophoresis to find DNA polymorphisms, with particular emphasis on the predictive value of DNA sequence data. We compare the efficiency of polymorphism detection by denaturing gradient gel electrophoresis with detection by restriction fragment length polymorphism (RFLP) analysis. The factor VIII gene appears to have a low level of DNA sequence polymorphism.(ABSTRACT TRUNCATED AT 250 WORDS)

Base Sequence↗
PubMedDate not supplied

Rapid ventricular pacing to control resistant neonatal atrioventricular re-entrant tachycardias.

A 3-week-old baby presented with recurrent supraventricular tachycardias unresponsive to medical treatment. Several DC shocks were required to terminate tachycardia. An abbreviated electrophysiological study was undertaken to determine the cause of the tachycardia. Rapid ventricular burst pacing successfully terminated repeated attacks of tachycardia until successful therapy with amiodarone was established. This patient demonstrates the value of pacemaker treatment of a resistant atrioventricular tachycardia in a neonate.

Amiodarone↗
PubMedDate not supplied

Prospective assessment of the aorto-iliac segment by visual interpretation of frequency analysed Doppler waveforms--a comparison with arteriography.

In a group of 83 patients the prospective Doppler assessment of disease in the aorto-iliac segment, obtained from visual interpretation of the frequency analysed Doppler waveforms, is compared with subsequent arteriographic findings. The Doppler technique proved to be particularly accurate in the severely diseased vessels (sensitivity 87%, specificity 88%) but tended to underestimate the extent of the minimal/moderate disease.

Angiography↗