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M J Dunphy

Publications and source records attributed to M J Dunphy.

6 recordsLinked to original sources
PubMed1990

Nitrate analysis by capillary gas chromatography.

A microanalytical gas chromatographic (GC) method for the analysis of nitrate in rat urine is described. The method involves the conversion of nitrate to nitromesitylene and quantitation using 3,4-dimethylnitrobenzene as an internal standard. The nitroaromatics were separated on a wide-bore capillary column and detected with a nitrogen-phosphorus thermionic detector. The method exhibited linearity over the range of 1.0 to 1000 microM nitrate, and the detection limit was 0.5 microM nitrate (200-microliters sample). The coefficient of variation (CV) range for intra-day precision was 2.2 to 5.8% (20 microM level) and 3.1 to 6.5% (200 microM level). Inter-day CVs ranged from 2.0 to 6.1% for the samples tested. The average recovery was 77% (20 microM level) and 80% (20 microM level). The accuracy of the GC method compared favorably with results obtained from a standard colorimetric nitrate assay. Interference by urinary chloride was eliminated by pretreatment of samples with saturated silver acetate. Both processed and unprocessed samples were stable for at least 60 days at -15 degrees C. The procedure was used to measure urinary nitrate in rats fed a custom low-nitrate diet.

Animals↗
PubMed1989

Quantitation of N,N,N',N'-tetrakis (2-hydroxypropyl)-ethylenediamine in plasma by gas chromatography.

A wide-bore capillary gas chromatographic method with nitrogen-selective thermionic detection is described for the quantitative analysis of N,N,N',N'-tetrakis (2-hydroxypropyl)ethylenediamine (Quadrol) in plasma. N,N,N',N'-tetrakis (2-hydroxybutyl)ethylenediamine is used as an internal standard. Rat or human plasma samples (0.5 ml) are mixed with internal standard, adjusted to alkaline pH and subjected to a single extraction with dichloromethane. Quadrol recovery from plasma typically exceeds 90%. The method is linear over the range 1.0-50 micrograms/ml. The working detection limit is 0.5 microgram/ml and the analysis time is under 7 min. The procedure has been used to obtain plasma concentration versus time data for the evaluation of Quadrol pharmacokinetics in rats.

Animals↗
PubMed1989

Beta-endorphin and components of depression as powerful discriminators between joggers and sedentary middle-aged men.

UNLABELLED: This study identifies the relative importance of resting plasma beta-endorphin, used as a marker of perceived stress, and components of non-clinical depression that discriminate between physically active joggers and sedentary men. The profiles of joggers (n = 10) and sedentary (n = 10) middle-aged men (40-60 yr) were compared. The jogger group had been running about 20 miles per week for at least 3 yr. RESULTS: as expected, the joggers exhibited greater physical fitness, but lower circulating beta-endorphin (measured with the subjects at rest). The joggers also exhibited greater emotional stability (Eysenck scores), and lower depression (MMPI Scale 2 scores). In addition, the joggers had lower scores on MMPI subscales of depression: subjective depression, physical malfunctioning, mental dullness, and brooding. Multivariate discriminant function analyses showed that subjective depression, beta-endorphin, and physical malfunctioning were powerful discriminators between the jogger and sedentary groups. IN CONCLUSION: (1) subjective depression appeared to be the MMPI component of depression that most powerfully discriminated between joggers and sedentary middle-aged men in this study. (2) Lower beta-endorphin may be an adaptation to exercise training and was related to greater emotional stability and lower depression, especially lower subjective depression. (3) The lower beta-endorphin in the jogger group may be related to lower perceived stress in the joggers, relative to the sedentary group.

Adult↗
PubMed1988

Resolution of diastereomers of N,N,N',N'-tetrakis(2-hydroxypropyl)ethylenediamine (quadrol) by reversed-phase high-performance liquid chromatography.

Quadrol, N,N,N',N'-tetrakis(2-hydroxypropyl)ethylenediamine, has been recently observed to display biological activity. It is an immunostimulant and has been implicated as a potentially useful agent in accelerated wound healing. Quadrol exists as a mixture of four unique diastereomers, each of which may, upon further investigation, display differences in biological activity. This paper describes an high-performance liquid chromatographic procedure (both analytical and prep) for the separation of the Quadrol diastereomers. Gas-liquid chromatography and NMR data are presented which corroborate the high-performance liquid chromatographic results. This procedure may be used to obtain pure Quadrol diastereomers, to monitor the progress of Quadrol synthesis from propylene oxide and ethylenediamine or to develop a quantitative assay for Quadrol diastereomers.

Adjuvants, Immunologic↗
PubMed1988

Promotion of wound collagen formation in normal and diabetic mice by quadrol.

The rate of collagen deposition in implanted polytetrafluoroethylene (PTFE) tubing in non-diabetic and streptozotocin-induced (STZ) diabetic mice was measured during 14 days post-wounding. At the time of implantation, test groups received injections of either Quadrol [N,N,N',N'-tetrakis(2-hydroxypropyl)ethylenediamine], glucan, or buffer in an area adjacent to the wound site. The accumulation of collagen in the implants of Quadrol-treated non-diabetic animals was more than 200% above control on days 8 to 11 and was 50% above control on day 14. In Quadrol-treated STZ-diabetic mice, the collagen accumulation gradually increased from 50% above control on day 8 to 200% above control on day 14. Treatment with glucan increased the collagen accumulation in normal mice 200 to 300% above control from days 8 to 11 respectively and then 30% above control on day 14. Collagen accumulation in the implants of the glucan-treated STZ-diabetic mice was similar to the control group. These results indicate that Quadrol promotes in vivo collagen synthesis and that Quadrol may be effective as a stimulator of wound healing in diabetic and non-diabetic animals.

Animals↗