[Swine leptospirosis. First isolation in Chile of Leptospira interrogans serovar tarassovi].
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Abattoirs↗
Biomedical subjects
M Frías
Publications and source records attributed to M Frías.
[Hyperemic reactivity scintigraphy in endothelial function].
OBJECTIVE: The aim of this study was to compare a recently described method to evaluate endothelial function; the hyperemic reactivity scintigraphy (HRS) with the ultrasonographic flow-mediated dilatation (FMD) in brachial artery and its relationship with myocardial SPECT. METHODS: 42 consecutive patients that underwent myocardial scintigraphy were included. Thirty-six patients had simultaneous measurement of FMD. Both studies were obtained after 5 minutes occlusion of the upper arm with a blood pressure cuff inflated at 250 mmHg. HRS was performed dynamically at rate 1 frame/sec during 3 minutes after intravenous injection of 740 MBq of Tc-99 sestamibi. Time-activity curves allowed obtaining the following indexes: medium hyperemic activity/medium contrallateral activity (MHA/MCA) and maximum hyperemic activity/maximum contrallateral activity (MxHA/CxHA). RESULTS: In 13 patients SPECT was normal. Twenty-nine patients had perfusion defects in scintigraphy. There was relationship between the FMD and the MHA/MCA (r = 0.23; p = 0.018) and the FMD and the MxHA/CxHA (r = 0.18; p = 0.05). Patients with alterations in the SPECT had an index MxHA/CxHA lower than patients with normal SPECT (1.8 +/- 0.2 vs 1.5 +/- 0.4; p = 0.04). We did not find relationship between FMD and alterations in SPECT. CONCLUSIONS: There is relationship between FMD and HRS. HRS is lower in patients with perfusion defects in the SPECT. HRS could provide additional value to myocardial scintigraphy.
Aged↗
[Genetic influence on energy requirements. I. Development of an experimental model].
In attempting to explore the mechanisms of interaction of genetic and environmental factors that affect the quantitative requirements of energy by man, the convenience of an animal model was considered and searched for. The idea was to start with male and female Wistar rats and through inbreeding segregate the highly effective users of energy from the poor users. The efficiency of dietary energy utilization was measured by the index of conversion (IC) defined as the dietary intake necessary to increase 1 g of body weight in a 32-day period, from day 21st to day 52nd of extrauterine life. The median value of the IC for all animals included in each experiment was the cut-off point to classify each individual as a good or a poor energy user. The first generation had three males and five females with a median IC = 2.90 and a range from 2.54 to 3.25. The proportion of males below the median was 3/3 while the proportion of females was 2/5. The difference in proportions was striking and led immediately to the consideration of a sex-link hypothesis, and to test it the, IC of 91 Wistar rats randomly selected at birth was obtained. The median value of the series was 2.99 with a range from 2.24 to 3.95. The proportion of male rats with values below the median was 33/38 while the corresponding proportion for females rats was 13/53. In other words, while nine of every ten male animals were good users of energy, only two out of ten females fell into this category.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
[Genetic influence on energy requirements. III. Multifactorial inheritance modified by gender].
A conversion index (CI) which measures the efficiency of utilization of dietary energy was found to be normally distributed in Wistar rats. The CI used was a ratio of the amount of food ingested to achieve an increment of one gram of body weight during the period of 32 days starting on day 21 after weaning. We have previously reported that male rats are more efficient energy converters than females. As a way to explore the hypothesis that the inheritance of the regulation of energy requirements is multifactorial, we mated F1 rats with high CI (poor energy converters) and studied the CI of their F2 offspring. The males behaved in agreement with the hypothesis as the F2 males had higher CI than the F1 males, but the behavior in females was different, i.e. the F2 were better converters than the F1. We have no explanation for this gender discrepancy.
Animals↗