[Echocardiographic assessment of the left ventricular fractional shortening/end-systolic stress relation in untreated hypertensive patients]

The present study was designed to assess the left ventricular (LV) function by the fractional shortening (FS)/end-systolic stress (ESS) relation in untreated hypertensive patients.

METHODS

Two patient groups were examined: group 1 was made up of 50 patients with essential mild hypertension (44 +/- 14 years) and group 2 consisted of 16 normotensives (35 +/- 12 years). LV mass, endocardial FS, mid-wall FS and meridional ESS were measured according to the classic formulas, as well as the 24-hour ambulatory blood pressure (ABP). FS/ESS relation was analysed in hypertensive patients by 2 different ways: 1 degree graphically, with the 95% confidence interval of the normal FS/ESS relation as a reference: 2 degrees statistically, by comparing the observed FS values with those FS value expected from ESS, using equations derived from normal subjects (McMemar chi 2 test, or binomial rule).

RESULTS

The graphic examination allowed for the identification of a depressed, normal or increased LV function in, respectively, 7, 31 and 12 patients, using the endocardial FS/ESS relation, against 30, 18 and 2 patients, using the mid-wall FS/ESS relation. Likewise, the statistical analysis of the differences between the observed FS values and the expected FS values showed 13 discrepancies, all of them being related to an overestimation of the LV function, an assessed by the endocardial FS/ESS relation (p < 0.01). Such a trend turned out to be more significant in patients with an increased ABP (n = 31; p < 0.05) than in "white coat" hypertensives (n = 9; p < 0.08): in contrast, it was of the same extent in patients with an increased LV mass (n = 17; p < 0.05) as in those with a normal LV mass (n = 33; p < 0.05).

CONCLUSIONS

1/After adjustment for ESS, mid-wall FS (a direct measure of myocardial fiber shortening) was more often decreased than endocardial FS (reflecting chamber dynamics). 2/Mid-wall FS was also found to be a better tool for assessing LV function in patients with normal LV mass, and, to a lesser extent, in "white coat" hypertensives.

Doping Graphitic and Carbon Nanotube Structures with Boron and Nitrogen

Composite sheets and nanotubes of different morphologies containing carbon, boron, and nitrogen were grown in the electric arc discharge between graphite cathodes and amorphous boron-filled graphite anodes in a nitrogen atmosphere. Concentration profiles derived from electron energy-loss line spectra show that boron and nitrogen are correlated in a one-to-one ratio; core energy-loss fine structures reveal small differences compared to pure hexagonal boron nitride. Boron and carbon are anticorrelated, suggesting the substitution of boron and nitrogen into the carbon network. Results indicate that singlephaase CyBxNx as well as separated domains (nanosize) of boron nitride in carbon networks may exist.

Primary left atrial angiosarcoma: follow-up by magnetic resonance imaging

We report the case of a primary left atrial angiosarcoma followed by MRI over a period of 1 year. The tumor was lobulated, with an initial central hyperintensity on T1-weighted images which disappeared after radiotherapy. Compared with other imaging modalities, MRI offered the most accurate information about the location, extent, and outcome under treatment.

[Postnatal growth of very low birth weight infants. II. Anthropometry at one year of age, a longitudinal study]

A prospective study up to one year of age, was done in 154 newborns with birth weight less than 1,501 g at a Metropolitan Hospital of Santiago, Chile, between 1983 and 1987. The patients were divided in groups A: 44 patients with birth weight less than 1,001 g; B: 68 patients with birth weights from 1,000 to 1,250 g and C: 48 patients with birth weight 1,251 to 1,500 g. At age one year weight of group A patients was 6,724 +/- 804 g; group B 7,782 +/- 927 g and group C 7,941 +/- 903 g. Weight and height of group A babies at one year of age were below 2 DS of the average weight and height for normal chilean babies of the same socioeconomic status and geographic area with 3,318 g mean birth weight. Group B and C were between 1 and 2 DS. Head circumference was within normal ranges in groups B and C patients, but in group A patients if was below 2 DS of the average.

Defecography commode

A mobile wooden commode was designed and built for use in defecography. The commode is made of 1/2-inch-thick plywood with birch veneer and a solid clear pine seat. Water or copper sheets are recommended for radiation filtration. A radiopaque ruler attached to the commode with a spring enables midline measurements. The modifications suggested by the authors have helped with setup and have improved the images acquired.

CO2 delivery system for double-contrast barium enema examinations

Patient discomfort following double-contrast barium enema examinations can be significantly reduced by using CO2 instead of room air. We describe an inexpensive and easily constructed CO2 delivery system for this examination.