DSC studies of the conformational stability of barstar wild-type.

The temperature induced unfolding of barstar wild-type of bacillus amyloliquefaciens (90 residues) has been characterized by differential scanning microcalorimetry. The process has been found to be reversible in the pH range from 6.4 to 8.3 in the absence of oxygen. It has been clearly shown by a ratio of delta HvH/delta Hcal near 1 that denaturation follows a two-state mechanism. For comparison, the C82A mutant was also studied. This mutant exhibits similar reversibility, but has a slightly lower transition temperature. The transition enthalpy of barstar wt (303 kJ mol-1) exceeds that of the C82A mutant (276 kJ mol-1) by approximately 10%. The heat capacity changes show a similar difference, delta Cp being 5.3 +/- 1 kJ mol-1 K-1 for the wild-type and 3.6 +/- 1 kJ mol-1 K-1 for the C82A mutant. The extrapolated stability parameters at 25 degrees C are delta G0 = 23.5 +/- 2 kJ mol-1 for barstar wt and delta G0 = 25.5 +/- 2 kJ mol-1 for the C82A mutant.

Clinical test of a blood pressure measurement device with a wrist cuff.

OBJECTIVE: To test a semi-automatic oscillometric blood pressure measurement device with a wrist cuff. METHODS: Two different test methods, partly based on European and American standards for clinical investigation of non-invasive sphygmomanometers, were worked out and compared. Mostly German guidelines were considered. The reference measurement was always performed using the standard auscultatory method on the upper arm. Altogether, 404 comparative measurements were performed in 108 patients. RESULTS: The mean differences (oscillometric wrist values minus auscultatory reference values) were -2.5+/-8.5 mmHg (mean +/- SD) for systolic blood pressure and -3.3+/-6.7 mmHg for diastolic blood pressure in method 1, and -3.6+/-6.9 mmHg for systolic blood pressure and -3.7+/-4.8 mmHg for diastolic blood pressure in method 2. The calculated correlation coefficients were betewen 0.77 and 0.89. A grading analysis was performed using the cumulative percentages of readings which showed a difference between test and reference measurements larger than 5, 10 and 15 mmHg. CONCLUSION:

Xylose-DNA: comparison of the thermodynamic stability of oligo(2'-deoxyxylonucleotide) and oligo(2'-deoxyribonucleotide) duplexes.

Measurements of differential scanning calorimetry, ultraviolet absorption and circular dichroism have been performed on two synthetic oligo(2'-deoxyxylonucleotides): (A) d[xA)3-(xT)3-(xA)3-(xT)3-T] and (B) d[(xA-xT)6-T], and on the oligo(2'-deoxyribonucleotide) (C) d[(A)3-(T)3-(A)3-(T)3]. Oligonucleotides having 2'-deoxyxylose instead of 2'-deoxyribose exhibit unusual thermodynamic, optical and structural features. At identical concentrations the transition temperatures of the oligo(2'-deoxyxylooligomers) are higher than those of the oligo(2'-deoxyribooligomers) indicating higher stability. The calorimetric transition enthalpy of (C) is 270 +/- 15 kJ . mol-1, the corresponding van't Hoff value is 280 +/- 15 kJ . (mol of cooperative unit)-1. The ratio of delta HvH/delta Hcal = 1.04 suggests all-or-none behaviour for the transition of the 2'-deoxyribose oligonucleotide. The analogous parameters of (A) are: delta Hcal = 310 +/- 30 kJ . mol-1, delta HvH = 220 +/- 30 kJ.(mol of cooperative unit)-1. The ratio of 0.71 indicates multistate melting for this compound. The sequence dependence of the thermodynamic quantities becomes apparent when the parameters of the alternating oligo(2'-deoxyxylonucleotide) d[(xA-xT)6-T] are compared to those of d[(xA)3-(xT)3-(xA)3-(xT)3-T). The values are delta Hcal = 330 +/- 30 kJ.mol-1; delta HvH = 180 +/- 15 kJ.(mol of cooperative unit)-1 delta HvH/ delta Hcal = 0.55. The transition enthalpy of the alternating oligo(2'-deoxyxylonucleotide) (B) is the highest but the cooperativity of transition is the lowest of the oligonucleotides studied. The circular dichroic spectra of the two oligo(2'-deoxyxylonucleotides) show unusual features in that d[(xA)3-(xT)3-(XA)3-(xT)3-T] exhibits a spectrum that is suggestive of a left-handed double helix, while the spectrum of the alternating oligo(2'-deoxyxylonucleotide) (B) resembles neither that of (C) nor that of (A).

[Preliminary clinical comparative study of a new blood pressure instrument with wrist cuff]. / Erste klinische Vergleichsuntersuchung eines neuen Blutdruckmessgerätes mit Handgelenkmanschette.

The present article reports on the first test results of a new oscillometric blood pressure device with a wrist cuff in clinical application. The test was performed in two different methodical studies. Both studies included 154 patients, from which 542 comparative measurements were acquired. The evaluated mean differences of systolic and diastolic blood pressures are -for study 1-1.2 mmHg (standard deviation +/- 7.9 mmHg) and 0.9 mmHg (+/- 6.2 mmHg), for study 2 1.6 mmHg (+/- 7.4 mmHg) and 3.5 mmHg (+/- 6.7 mmHg) and show a good agreement with the method of Riva-Rocci/Korotkoff. The results are discussed in detail and conclusions for applicable fields of use for the device and for additional clinical studies are drawn.