Reliability of intra-abdominal pressure measurements using the modified Kron technique.

OBJECTIVES: Assessment of intra-abdominal pressure (IAP) and the likelihood of abdominal compartment syndrome using valid and reliable measures is an important tool in the assessment of critically ill patients. The current method of relying on a single IAP per measurement period to determine patient clinical status raises the question: is a single intermittent IAP measurement an accurate indicator of clinical status or should more than one measurement be taken per measurement period? METHODS: This study sought to assess the reliability of IAP measurements. Measurements were taken using the modified Kron technique. A total of two transvesical intra-abdominal pressure measurements were undertaken per patient using a standardized protocol. Recordings were taken at intervals of 5 minutes. RESULTS: The majority of participants (58%) were surgical patients. Thirty-two were males and the mean age was 58 years (SD: 16·7 years). The concordance correlation coefficient between the two measurements was 0·95. Both the scatter and Bland-Altman plots demonstrate that the comparisons of two measurements are highly reproducible. CONCLUSION: The findings of this study suggest that conducting two IAP measurements on single patient produce comparable results; therefore, there appears to be no advantage in doing two IAP measurements on a single patient. The measurement of an IAP requires the implementation of a standardized protocol and competent and credentialed assessors trained in the procedure.

Theoretical investigation of the interaction of CH(4) with Al(2) and Al(3) neutral and charged clusters.

We have studied the interaction of CH(4) with Al(2) and Al(3) neutral and charged clusters in the two lowest lying spin states using density functional theory. These calculations, via extended search, are used to determine the stable positions of H and CH(3) near the cluster, and the transition state to break the H-CH(3) bond. In all cases, stable methyl-aluminum-hydrides are possible. The H desorption is studied by means of vibration analysis and application of transition state theory. A common observed trend is that, in breaking the H-CH(3) bond, the interacting H atom is attached to the "surface" of the clusters attracting some negative charge of approximately 0.2e. The charge transfer is illustrated using the corresponding orbitals near the transition state in conjunction with the computed Mulliken population analysis. Thermal vibrations, generally, do not enhance the reaction. In all exothermic cases, the binding energy toward CH(3)+HAl(n) (charge) increases with increasing charge of the original Al(n) ((q=-1,0,1)) cluster. Although Al lacks occupied d-orbitals, the small Al clusters reduce the (free methane) CH(3)-H dissociation barrier except for Al(3) ((q=-1,0)). The relevant reactions in desorption require approximately 400-700 degrees C.

Inhibition of angiotensin converting enzyme by L-alanyl-4 or 5-substituted-L-prolines and their N alpha-phosphoryl-derivatives.

A series of L-alanyl-4 or 5-substituted L-prolines, such as L-alanyl-L-thiazolidine-4-carboxylic acid, L-alanyl-5-oxo-L-proline, L-alanyl-trans-4-hydroxy-L-proline and L-alanyl-cis-4-hydroxy-L-proline as well as their corresponding N alpha-phosphoryl derivatives, were synthesized and studied for inhibition against angiotensin converting enzyme. Furanacryloyl-phenylalanyl-glycyl-glycine was used as substrate in 50 mM Tris hydrochloride buffer at pH 7.5 containing 1 microM zinc acetate. N alpha-Phosphoryl-L-alanyl-L-thiazolidine-4-carboxylic acid and N alpha-phosphoryl-L-alanyl-trans-4-hydroxy-L-proline competitively inhibit angiotensin converting enzyme with Ki values of 68 microM and 89.3 microM, respectively. Smaller inhibition against angiotensin converting enzyme was obtained with the rest of compounds studied here.