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Biomedical subjects

G Warneke

Publications and source records attributed to G Warneke.

At least 19 recordsLinked to original sources
PubMed1996

[Diagnosis of magnesium deficiency in intensive care patients].

AIM: Magnesium deficiency was investigated in critically ill patients, comparing measurements of plasma concentrations with the results obtained by the magnesium tolerance test. DESIGN AND METHODS: 20 critically ill patients (5 females, 15 males) between the ages of 27 and 86 were investigated. Magnesium plasma concentrations were determined before the magnesium tolerance test according to Ryzen was performed. For this purpose, magnesium sulfate (0.1 mmol/kg) was infused intravenously over four hours. Renal magnesium excretion was measured in the 24 h urine beginning at the start of the infusion. Magnesium concentrations in plasma and urine were determined using atomic absorption spectrophotometry. MAIN RESULTS: In 12 patients magnesium plasma concentrations were decreased to 0.58-0.79 mmol/l. 6 patients showed values within the normal range of 0.80 to 1.0 mmol/l. In 2 patients the plasma concentration was increased to 1.07 and 1.27 mmol/l. Parenteral magnesium tolerance testing revealed a considerable magnesium deficiency by retention of 65-100% of the loading dose in 14 of the 20 patients. The remaining 6 patients retained 23-48% of the loading dose, thus demonstrating a moderate magnesium deficiency. CONCLUSION: Determination of magnesium plasma concentration appears suitable as an informative preliminary survey, since low values are reliable indicating a magnesium deficiency. However, this study confirms that normal magnesium plasma concentrations do not exclude a considerable magnesium deficiency, which is more sensitively determined by the magnesium tolerance test.

Adult↗
PubMed1995

Magnesium and calcium concentration in the pregnant and non-pregnant myometrium.

OBJECTIVES: To investigate the effect of labor on the magnesium and calcium concentrations in the human myometrium and to compare them with the concentrations in the non-pregnant uterus. METHOD: Samples of the isthmic part of the uterus were taken from 42 patients not in labor, 31 patients in regular labor during a cesarean section, and 37 premenopausal patients on whom a hysterectomy was performed. RESULTS: (i) The magnesium concentration dropped significantly during labor; (ii) the calcium concentration in the tissue showed no significant changes during labor; (iii) the magnesium and calcium concentrations were significantly higher during pregnancy; (iv) the distribution of electrolytes in the myometrium differed significantly in the corpus, isthmus and cervix uteri. CONCLUSIONS: The electrolyte concentration in the myometrium depends on the place of removal. A low magnesium concentration in the pregnant human myometrium could be a cause of premature labor.

Calcium↗
PubMed1994

Comparison of the determination of magnesium by methylthymol blue spectrophotometry and atomic absorption spectrophotometry.

Plasma samples (n = 155) of 30 patients on an intensive ward were analysed for magnesium simultaneously by atomic absorption spectrophotometry (AAS) and methylthymol blue spectrophotometry. Methylthymol blue spectrophotometry was performed at the bedside, using two different multianalysers, Easy ST 1 and Easy ST 2, Merck, D-Darmstadt. Precision was 12.2% (Easy ST 1) and 17.1% (Easy ST 2), and the average value was 0.89 mmol/l, which was above the expected range (0.72-0.88 mmol/l). Accuracy was 16.25% (Easy ST 1) and 8.75% (Easy ST 2). Analyser 2 was more accurate (8.75% versus 6.25%) but less precise (17.1% versus 12.2%) than analyser 1. Precision of AAS was between the expected values of 0.69 and 0.84 mmol/l. Easy ST and AAS gave significantly different values (p < 0.0001) for 155 measurements. Comparison of AAS and methylthymol blue spectrophotometery showed that methylthymol blue spectrophotometry produced higher values than AAS (mean difference 0.186 mmol/l). Furthermore, analyses of 40 samples of a standardized plasma concentration with methylthymol blue spectrophotometry showed a very low precision (15.3%). Easy ST cannot be assigned for urinary measurements of magnesium. Experimentally measured samples gave unaccountable results.

Bromthymol Blue↗
PubMed1993

Bioavailability and pharmacokinetics of fluoride from two glutamine monofluorophosphate preparations.

A two-way cross-over study was conducted on 12 Caucasian male healthy volunteers aged between 25 and 38 years in order to determine the bioavailability and pharmacokinetics of fluoride after single oral administration in fasting conditions of two products (tablets and powder for oral use) of L-glutamine monofluorophosphate (G-MFP, CAS 116420-36-1). The two products contained the equivalent of 10 mg F and the equivalent of 300 mg CA as calcium gluconate and calcium citrate. The two products were found bioequivalent with regard to the release of fluoride, both on the basis of the AUC and Cmax of fluoride in plasma and of the urinary excretion of fluoride during the 48 h following the administration. The pharmacokinetics of fluoride in plasma is characterized by a short lag time (< 6 min), a rapid absorption, a peak which is reached 0.5-1.0 h after administration, followed by a biphasic elimination. The first phase with a k alpha of 1.8 h-1 is followed by a slower phase with a K beta of 0.14 h-1. Probably the terminal elimination rate is slower, about 0.05 h-1. The urinary excretion of fluoride during the 48 h after administration accounted for 40-50% of the administered dose of fluoride. The results are consistent with those found in previous studies after administration in fasting conditions of sodium fluoride or sodium monofluorophosphate alone or in combination with calcium salts.

Adult↗
PubMed1993

Effects of meal on the pharmacokinetics of fluoride from oral monofluorophosphate.

A two-treatment cross-over study was conducted on 8 Caucasian male healthy volunteers aged between 26 and 32 years in order to determine the influence of a standard meal on the bioavailability and pharmacokinetics of fluoride after a single oral administration of tablets containing the equivalent of 10 mg fluoride as sodium monofluorophosphate (Na-MFP, CAS 10163-15-2) in a fixed combination with 300 mg Ca as calcium gluconate and calcium citrate. The meal provoked a significant delay of the appearance of fluoride in blood (from 4 to 11 min), a slowing of the absorption rate, a prolongation of tmax (from 34 to 146 min), a decrease of Cmax (from 369 to 122 ng/ml) and a prolongation of the Mean Residence Time (from 7.1 to 9.1 h). However, the amount of fluoride entering in the systemic circulation was not affected by the meal, as shown by the ANOVA on the AUC and on the cumulated urinary excretion of fluoride in the 48 h following the administration of Na-MFP. It is concluded that appropriate meals do not influence the amount of absorbed fluoride from Na-MFP, and that they modify the rate of absorption with pattern that may improve the safety and possibly also the efficacy of Na-MFP.

Administration, Oral↗
PubMed1992

[Comparison of 24-hour blood pressure measurement with ergometry in patients with hypertension].

24-h-Ambulatory blood pressure monitoring and bicycle ergometry were compared in 112 patients with untreated mild to moderate essential hypertension. Patients with high blood-pressure values above 220 mmHg during ergometry showed a significantly higher number of blood-pressure peaks above 180 mmHg. There was no significant correlation between the level of the blood-pressure rise during ergometry and the mean values of blood pressure during the 24-h period neither in the night- or the daytime period, nor of the peak values of the 24-h profile. Blood-pressure values during ergometry in patients with high numbers of systolic blood-pressure peaks above 180 mmHg during ambulatory monitoring did not differ significantly from patients with blood-pressure peaks above 180 mmHg during ambulatory monitoring. Patients with marked blood-pressure rise during ergometry seem to demonstrate a higher number of blood-pressure peaks during daytime. On the other hand, patients with an elevated number of blood-pressure peaks do not necessarily show a high blood-pressure rise during ergometry.

Adult↗
PubMed1992

[Diagnostic significance of absent nocturnal blood pressure decrease in 24-hour long-term blood pressure measurement].

Patients (pts) with essential hypertension normally exhibit a typical diurnal variation with a nocturnal blood-pressure (BP) decreased. A lack of this periodicity is often reported in pts with secondary hypertension. 24-h BP measurement was therefore performed in 308 pts with essential hypertension, and in 172 pts with secondary hypertension, in order to evaluate the diagnostic value of nocturnal BP decrease. Diagnoses of the secondary hypertensives were: renoparenchymatous hypertension (n = 29), diabetic nephropathy (n = 24), morbus Conn (n = 6), renal artery stenosis (n = 32), pheochromocytoma (n = 5), hemodialysis pts (n = 30), and kidney transplantation (n = 44). Pts with essential hypertension showed a mean systolic and diastolic BP decrease during the nighttime period of 22 +/- 7 mmHg and 17 +/- 5 mmHg, respectively. In contrast, the corresponding values in secondary hypertension were 5.7 +/- 9.2 mmHg (systolic decrease) and 5.2 +/- 5.9 (diastolic decrease). Pts with pheochromocytoma who had a nighttime increase in BP demonstrated the greatest difference from the essential hypertensives, followed by pts with either diabetic nephropathy or after kidney transplantation. A lack of nocturnal BP decline (less than 10% of the daytime values) was detected in 69.8% of pts with secondary hypertension, but only in 5.2% of pts with essential hypertension. In summary, these results suggest that the absence of a nighttime decline in BP during 24-h ambulatory monitoring is an indication of secondary hypertension and should lead to further investigations. Furthermore, a nightly hypertension is associated with a higher risk of complications.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenal Gland Neoplasms↗
PubMed1991

[Importance of 24-hour blood pressure monitoring in secondary hypertension].

A typical diurnal variation in blood pressure is observed in patients with essential hypertension. Attenuation or lack of circadian periodicity might be expected in patients with secondary hypertension. Therefore, non invasive ambulatory blood-pressure monitoring was performed in 172 patients with secondary hypertension and in 201 patients with essential hypertension. The following patients with secondary hypertension were investigated: renoparenchymatous nephropathy (n = 29), diabetic nephropathy (n = 24), morbus Conn (n = 6), renal artery stenosis (n = 32), pheochromocytoma (n = 5), hemodialysis patients (n = 30), and patients after kidney transplantation (n = 44). In addition, 36 pregnant women (17 normotensives, 19 hypertensives) were studied. 98.5% of patients with essential hypertension showed a nightly decline in blood pressure of at least 15 mmHg (systolic + diastolic), whereas 70% of patients with secondary hypertension showed either an attenuated circadian rhythm or no circadian rhythm. Patients with pheochromocytoma who had a nighttime increase in blood pressure demonstrated the greatest difference in the essential hypertension collective, followed by patients with diabetic nephropathy and patients after kidney transplantation. After successful treatment of the condition leading to hypertension, circadian periodicity returned in some patients. In summary, these results suggest that the absence of a nighttime decline in blood pressure during 24-h-ambulatory monitoring is an indication of secondary hypertension, which should be further investigated. As a practical consequence, antihypertensive drugs should also be applied in an evening dose in secondary hypertensives. Noninvasive ambulatory blood-pressure monitoring is recommended for treatment control, especially in patients who need an efficient blood-pressure control.

Adrenal Gland Neoplasms↗
PubMed1990

Comparison of the antihypertensive efficiency of nitrendipine, metoprolol, mepindolol and enalapril using ambulatory 24-hour blood pressure monitoring.

In a randomized 6-month study of 201 patients, the antihypertensive efficiency of the calcium antagonist nitrendipine, the beta 1-selective blocker metoprolol, mepindolol, the beta blocker with intrinsic activity and the angiotensin-converting enzyme inhibitor enalapril were compared as monitored by 24-hour ambulatory blood pressure (BP) measurements. The study was designed so that a comparable decrease in casual BP values was obtained with all 4 drugs. If normotension was not achieved with monotherapy, a diuretic also was administered. Pretreatment casual BP and mean 24-hour ambulatory BP values did not differ between the 4 groups. Normotension as assessed by casual BP measurements was observed in all 4 groups after 6 months of therapy, there being no significant differences between the groups. However, significantly more diuretics were required in the mepindolol (n = 14) and in the enalapril (n = 20) groups compared to the nitrendipine (n = 5) and metoprolol (n = 7) groups. Despite comparable casual BP control, the 4 groups differed significantly in their mean 24-hour measurements. The greatest systolic and diastolic BP decreases were seen in the metoprolol group. Metoprolol was also the most effective drug in decreasing the frequency of systolic pressure peaks greater than 180 mm Hg. Both beta blockers and enalapril significantly decreased the morning BP increase compared to the values before treatment, while nitrendipine did not. These data show that casual BP measurement is not a good predictor of 24-hour BP in patients taking hypertensive therapy. Despite an equal degree of "office" BP control, different antihypertensive regimens do not confer the same degree of "nonoffice" BP control.

Adult↗
PubMed1990

[Plasma endothelin in normal probands and patients with nephrologic-rheumatologic and cardiovascular diseases].

Plasma concentrations of the recently isolated potent vasoconstrictory peptide endothelin were measured in 382 patients. The investigations were performed by means of a sensitive radioimmunoassay specific for Endothelin-1, 2. The results from 110 healthy volunteers displayed a normal range of 44.67 +/- 3.51 pg/ml. Significantly raised levels were found in 33 patients with chronic end-stage renal failure both before and after hemodialysis. In contrast, 35 patients with compensated renal insufficiency did not differ from the normals. Sixty-five patients after kidney transplantation revealed significantly elevated levels, as did 27 patients with acute myocardial infarction, 8 after coronary bypass surgery, and 5 with liver cirrhosis. The mean values of 27 patients with untreated hypertension, 22 with secondary hypertension, of various causes and 16 with coronary artery disease were comparable to the normal population. The values were significantly decreased in 9 pregnant women with hypertension and proteinuria. A marked decline was found in 5 patients with systemic lupus erythematodes, while 20 patients with rheumatoid arthritis demonstrated only a slight decrease. The pathophysiological role of endothelin as a local or circulating hormone in regulating systemic blood pressure or release of other hormones remains to be determined.

Arthritis, Rheumatoid↗
PubMed1989

[Absence of nocturnal decrease in blood pressure in 24-hour blood pressure monitoring: an indication of secondary hypertension].

Non invasive 24 hours ambulatory blood pressure monitoring was performed in 81 patients with secondary hypertension (renoparenchymatous nephropathy n = 15, diabetic nephropathy n = 10, Conn's disease n = 4, renal artery stenosis n = 15, pheochromocytoma n = 2, hemodialysis patients n = 15 and patients after kidney transplantation n = 20). The results were compared to 201 patients with essential hypertension. The results showed that 98.5% of patients with essential hypertension have a nightly decline in blood pressure of at least 15 mmHg (systolic + diastolic), whereas 69% of patients with secondary hypertension showed either an attenuated circadian rhythm or no circadian rhythm. Patients with pheochromocytoma who had a night time increase in blood pressure demonstrated the greatest difference to the essential hypertension collective followed by patients with diabetic nephropathy, Conn's disease and the group of patients after kidney transplantation. After successful treatment of the condition leading to hypertension circadian periodicity returned in some patients. In summary these results suggest that the absence of a night time decline in blood pressure during 24-hour-ambulatory monitoring is an indication of secondary hypertension.

Adrenal Gland Neoplasms↗
PubMed1989

Treatment of reperfusion injury with intracoronary calcium channel antagonists and reduced coronary free calcium concentration in regionally ischemic, reperfused porcine hearts.

The effect of intracoronary diltiazem, EGTA (ethylene-bis-(beta-aminomethylether)-N,N'-tetraacetic acid), nifedipine, verapamil and isotonic saline solution as placebo on reperfusion injury was investigated in regionally ischemic, reperfused porcine hearts. The left anterior descending coronary artery was distally occluded for 45 min and was reperfused for 3 days. Intracoronary infusion was started immediately before reperfusion and continued during 45 min of reperfusion. Infarct size was determined as the ratio of infarcted (tetrazolium stain) to ischemic myocardium (dye technique). Regional systolic shortening was assessed by sonomicrometry. Apart from left ventricular end-diastolic pressure before ischemia and during 45 min of reperfusion, global hemodynamic values in the five treatment groups did not differ; in particular, calculated left ventricular oxygen consumption before and during ischemia was equally low. Intracoronary EGTA decreased coronary venous free calcium concentration to about 70% of baseline value. Infarct size was reduced from 76 +/- 10% (control group, n = 8) to 60 +/- 10% (p less than 0.01) by intracoronary diltiazem (n = 8) and to 55 +/- 15% (p less than 0.01) by intracoronary EGTA (n = 8). Insignificant reductions in infarct size were found after treatment with intracoronary verapamil (63 +/- 18%, n = 8) and intracoronary nifedipine (68 +/- 9%, n = 7). Regional systolic shortening of the risk region, which did not differ among the groups before occlusion and during ischemia, recovered to the greatest extent in the EGTA-treated pigs (p less than 0.01 compared with values in the control group). Treatment with intracoronary calcium antagonists resulted in only marginal improvement of systolic shortening.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Influence of CAPD and residual diuresis on the serum levels of alpha-1-microglobulin in end-stage renal disease.

The chronic retention of proteins of low molecular weight (LMWP) seems to be connected with some unsolved problems of end-stage renal disease (e.g. reduced immune function, AB amyloidosis, hormonal imbalances), irrespective of the type of renal replacement therapy. Therefore, several recently discovered LMWPs such as alpha 1-microglobulin have to be evaluated concerning their contribution to the uremic syndrome. Although we observed a considerable daily loss of total protein into the CAPD dialysate, no differences were found in the removal of small proteins (MW less than 68 kilodaltons) when compared to conventional hemodialysis. Maintenance of renal function (residual diuresis greater than 100 ml/day) seems to be more potent keeping the serum concentrations of LMWP low than CAPD or hemodialysis.

Adult↗
PubMed1989

[24-hour blood pressure behavior in patients with untreated and treated hypertension in comparison with normotensive patients].

Blood pressure was continuously monitored over 24 h in 201 patients with mild to moderate essential hypertension using a noninvasive method. Measurements were made both before and after 6 months of antihypertensive treatment and the data were compared to results from 100 normotensive patients. The frequency with which blood pressure values above 140/90 mm Hg occurred during the 24-h period proved to be the most reliable parameter for distinguishing between hypertensive and normotensive profiles. The blood pressures of all patients could be normalized (less than 140/90 mm Hg) on single or combined drug therapy as assessed by casual measurement. However, significant differences were observed between the 24-h profiles of the treated patients and the control group. The mean 24-h blood pressure, the mean day and nighttime blood pressures, the mean hourly pressure, and the frequency of increased blood pressure values were all significantly higher in the patients on medication as compared to the normotensive controls. This would suggest that normotension, as defined by the control group, cannot be attained with antihypertensive medication. In conclusion, 24-h continuous blood pressure monitoring allows a better evaluation of blood pressure profiles and consequently, will be of greater value in assessing cardiovascular risk than occasional random measurements.

Adult↗