PubMed Health⌕ Search

Biomedical subjects

M K Yousef

Publications and source records attributed to M K Yousef.

At least 37 records · Page 2Linked to original sources
PubMed1979

Cardiac output during rest and exercise in desert heat.

Cardiac output and stroke volume were measured in two environments and at metabolic rates ranging from rest to the maximum rate that could be sustained for 25 minutes. One environment was indoors at about 23 degrees C, the other outdoors in desert sunshine and low water vapor pressure. The age range of the one female and four of the male subjects was from 19 to 40; the fifth male subject was 85 years old. Cardiac output was the same in the two environments; stroke volume was less at higher metabolic rates in the heat. The cardiac output for the old man was about one-tenth less and stroke volume about 20 ml less than that observed for the same work 50 years earlier.

Adult↗
PubMed1975

The electrocardiogram of burros.

Electrocardiograms of two burros are presented. Compared to those seen in humans, amplitudes were lower, especially in lead I, and marked prolongations were observed in P-Q and Q-T intervals. The QRS axes were craniad.

Animals↗
PubMed1975

Thyroid activity in desert rodents: a mechanism for lowered metabolic rate.

Desert rodents are known to exhibit three different levels of metabolic rate (MR) when related to the mouse-elephant equation. Several species have an MR that is either higher, lower, or similar to that predicted from the equation. The role of thyroid function as a possible mechanism associated with these different MR was examined in 12 species of desert rodents, representing 3 families and 3 different biotic communities. Thyroidal 131I uptake, ratio of neck-to-thigh 131I counts per minute (N/T ratio), thyroxine secretion rate (TSR), and plasma protein binding sites were used as indices of thyroid function. When relating thyroid function to MR, TSR was found to be low in species exhibiting low MR and vice versa. Other thyroid indices did not show a consistent relationship to MR. Also, TSR seems to be related to ecologic distribution: low TSR in desert areas and high TSR in arid woodland and montane forest areas. TSR was found to be correlated to body weight. The low TSR associated with reduced MR represents a useful adaptive mechanism for survival of desert rodents under their natural stressful environment.

Animals↗