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Biomedical subjects

C M Wagner

Publications and source records attributed to C M Wagner.

9 recordsLinked to original sources
PubMed1995

Circadian blood pressure variation versus renal function.

Several published reports describe an abnormal circadian blood pressure profile in chronic renal failure subjects. Factors other than renal failure, including age, diagnosis of diabetes mellitus, autonomic dysfunction, and race, also may affect circadian blood pressure profiles. To further elucidate the relationship between renal function and circadian blood pressure variation, we compared day/night circadian blood pressure changes in three groups of male veteran hypertensive patients: group A, creatinine clearance (CC) > 80 mL/min, n = 20; group B, CC 20 to 80 mL/min, n = 19; and group C, CC < 20 mL/min, n = 14. We use postural changes in catecholamines, renin, and aldosterone as a measure of autonomic function. No significant difference in day/night percent change in systolic, diastolic, mean arterial pressure (MAP), or heart rate was seen by renal function group. Regression analysis using age, diagnosis of diabetes mellitus, postural hormonal changes, and creatinine clearance found race to be the only significant predictor of the day/night percent change in MAP (P < 0.05). Compared with whites, black subjects had higher nocturnal heart rates (P = 0.01); smaller day/night heart rate changes (P = 0.03); significantly higher diastolic blood pressure (P = 0.01); and a trend toward smaller day/night change in diastolic blood pressure (P = 0.06). In conclusion, renal function level does not influence day/night blood pressure changes. The blunting or reversal of the normal circadian blood pressure pattern seen in some chronic renal failure hypertensive subjects may be attributable to the association between chronic renal failure and cofactors associated with abnormal circadian blood pressure, including black race and possibly severity of atherosclerosis.

Aldosterone↗
PubMed1995

The effect of sleep intervals on analysis of 24-h ambulatory blood pressure data.

Twenty-four hour blood pressure exposure and circadian blood pressure variability may be important predictors of hypertensive end-organ damage. Since sleep is a major determinant of circadian blood pressure decline, day/night blood pressure changes may be affected by sleep intervals. The current study compares 24-h blood pressure results with and without adjustment for patient-specific sleep intervals. Forty male hypertensive patients (22 with renal insufficiency and 18 with normal renal function) underwent 24-h blood pressure study with SpaceLabs 90207 monitors. They also filled out sleep questionnaires to evaluate time awake and asleep during the day and night intervals. Data was analyzed with and without adjustment for daytime asleep and nighttime awake intervals. The percent change in systolic, diastolic, and mean arterial pressure as well as heart rate was not different statistically or clinically with or without adjustment for sleep intervals. Nevertheless, there was a progressive increase in the day versus night percent change in these hemodynamic parameters with adjustment for sleep intervals. When we used arbitrary cut-offs to define "non-dipper", ie, less than 10% drop in a given hemodynamic parameter, and used patient-specific sleep intervals, clinically and statistically different numbers of "non-dippers" were seen versus sleep unadjusted data (19 v 12, using diastolic BP, P < .01). In conclusion, it may not be necessary to adjust for sleep intervals when relating 24-h blood pressure and day/night blood pressure variability to hypertensive end-organ damage. However, arbitrary cut-offs to define "non-dippers" may be greatly and capriciously affected by sleep/awake intervals.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Pressure↗
PubMed1992

Validation of the simultaneous determination of methylprednisolone and methylprednisolone acetate in human plasma by high-performance liquid chromatography.

A reversed-phase high-performance liquid chromatographic procedure was developed that accurately quantitates methylprednisolone (MP) and methylprednisolone acetate (MPA) in human plasma over the range 2.00-50.0 ng/ml. The internal standard, fluorometholone, was added to an aliquot of sodium fluoride-potassium oxalate-derived plasma. Samples were prewashed with hexane and extracted twice with methylene chloride. The extracts were dried with anhydrous sodium sulfate, centrifuged, and the organic layer separated and dried under nitrogen. The samples were reconstituted in mobile phase and washed an additional time with hexane before 100 microliters were injected onto a Beckman/Altex Ultrasphere ODS column with ultraviolet absorbance detection at 254 nm. Composition of the mobile phase was acetonitrile-water-glacial acetic acid (33:62:5, v/v/v). Calibration curves were obtained by unweighted, linear regression of peak-height ratios of MP (or MPA)/internal standard versus theoretical concentrations of MP or MPA using a Hewlett-Packard 3357 Laboratory Automation System. Extraction efficiencies for MP and MPA over the linear range were 86.4 and 84.7%, respectively. This method was successfully implemented for the analysis of specimens generated from a single-dose bioavailability and safety study for a new formulation of Depo-Medrol sterile aqueous suspension.

Chromatography, High Pressure Liquid↗
PubMed1985

The role of context in facilitating syntactic decoding in aphasia.

This study assessed the ability of aphasic listeners to use linguistic context to facilitate the comprehension of complex syntactic structures. Fourteen aphasic subjects were presented with reversible active and reversible passive sentences in each of three conditions: isolation; a semantically neutral prior-sentence context; and a semantically supportive prior-sentence context. Following presentation of the contextual and target sentences the subjects were asked a question that assessed their appreciation of the subject/object relationship in the target sentence. A forced-choice-response paradigm was employed. The results indicated that those subjects who had the most difficulty comprehending reversible passive sentences in isolation were able to benefit from the supportive contexts. The comprehension of active sentences was not facilitated by the contexts. These results were interpreted with respect to the comprehension strategies used by aphasic listeners to integrate information from different sources.

Adult↗
PubMed1985

Anti-Bermuda grass RAST binding is minimally inhibited by pollen extracts from ten other grasses.

This article addresses the question, Does sensitization with Bermuda grass pollen generate IgE antibodies that cross-react with other grasses? We found that none of ten non-Bermuda grass extracts attained 50% inhibition of RAST binding between sera from patients in Arizona and Bermuda-coupled disks whereas Giant Bermuda grass extract was completely cross-reactive with Common Bermuda grass.

Binding Sites, Antibody↗
PubMed1983

The effect of macrophages on the metabolism of glomerular cells: preliminary studies.

Human glomerular epithelial and mesangial cells were grown in vitro and shown to have distinctive morphologic and functional characteristics. Glomerular epithelial cells or mesangial cells cultured in wells of flat-bottom microtiter plates were treated for 4 hr with dialyzed macrophage supernatants obtained from cultures of mouse peritoneal macrophages or human peripheral monocytes. DNA, RNA, and protein synthesis were evaluated by incorporation of radioactive precursors. Macrophage supernatants stimulated RNA and protein synthesis in epithelial cells but failed to stimulate DNA synthesis. The macrophage factor(s) showed a dose-response activity, was nondialyzable, was destroyed by freezing and thawing, and did not seem to be species specific. In contrast to the results obtained with glomerular epithelial cells, mesangial cell DNA synthesis was stimulated by macrophage supernatants. The observed metabolic effects of macrophage products on glomerular cells in vitro are consistent with observations of in vivo glomerular response to injury in which epithelial cells may be activated to form new basement membrane while mesangial cells may respond by proliferating. These data further support the theory of macrophage involvement in the pathology of glomerulonephritis.

Animals↗
PubMedDate not supplied

Isolator environments.

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Environment, Controlled↗