Comparison of the sit-up test and head-up tilt test for assessing blood pressure and hemodynamic responses in healthy young individuals.

OBJECTIVE: The sit-up test is used to assess orthostatic hypotension, without the use of a tilt table, in populations who are unable to stand. The primary objective of this study was to determine the differences in blood pressure and hemodynamic responses between the sit-up and head-up tilt tests. The secondary objective was to determine the hemodynamic responses related to changes in blood pressure during each test. METHODS: Nineteen healthy volunteers (nine males, aged 24.3 ± 2.4 years) underwent the sit-up and head-up tilt tests. Systolic and diastolic blood pressure, heart rate, stroke volume, cardiac output, and total peripheral resistance were measured. RESULTS: The increase in systolic blood pressure (15 ± 9 vs. 8 ± 8 mmHg) was greater, while the increase in heart rate (8 ± 5 vs. 12 ± 8 bpm) and reduction in stroke volume (-17 ± 10 vs. -21 ± 10 ml) were smaller during the sit-up test than during the head-up tilt test (P < 0.05). Additionally, the increases in blood pressure variables were significantly associated with the increase in total peripheral resistance (P < 0.05), but not with changes in other hemodynamic variables in both tests. CONCLUSION: Although the magnitudes of changes in systolic blood pressure, heart rate, and stroke volume differed between the tests, the hemodynamic variable related to changes in blood pressure was the same for both tests. These results may contribute to the clinical application of the sit-up test for identifying the presence and hemodynamic mechanisms of orthostatic hypotension.

Methyl α-l-sorboside monohydrate.

Methyl l-sorboside monohydrate, C7H14O6·H2O, was prepared from the rare sugar l-sorbose, C6H12O6, and crystallized. It was confirmed that methyl l-sorboside formed α-pyran-ose with a 2 C 5 conformation and crystallized with one water molecule of crystallization. In the crystal, mol-ecules are linked by O-H⋯O hydrogen bonds, forming a three-dimensional network. The unit-cell volume of the title compound, methyl l-sorboside monohydrate, is 481.13 (2) Å3 (Z = 2), which is about 108.16 Å3 (29.0%) greater than that of half the amount of the chemical α-l-sorbose [745.94 (2) Å3 (Z = 4)].

Ethyl α-l-sorboside.

Ethyl l-sorboside, C8H16O6, was prepared from the rare sugar l-sorbose, C6H12O6, and crystallized. It was confirmed that ethyl l-sorboside formed α-pyran-ose with a 2 C 5 conformation. In the crystal, mol-ecules are linked by O-H⋯O hydrogen bonds, forming a three-dimensional network. The unit-cell volume of the title ethyl α-l-sorboside is 940.63 Å3 (Z = 4), which is about 194.69 Å3 (26.1%) bigger than that of l-sorbose [745.94 Å3 (Z = 4)].