Biomedical subjects

F J Diaz

Publications and source records attributed to F J Diaz.

4 recordsLinked to original sources

PubMed1992

Sarcomas of the head and neck.

Fourteen cases of sarcomas involving the head and neck over a period of 15 years were reviewed. The male to female ratio was 3.5:1. Mean age of occurrence was 33.4 years, with a range of 5-84 years. Soft tissue was the site of origin in three cases, maxilla in four and mandible in seven patients. Radical surgery with resection of adequate disease-free margins was the most effective mode of treatment. Radiotherapy and chemotherapy was used in selected cases. Recurrence occurred in 42.9% of patients, and was the main cause of death. Three patients (21.4%) developed distant metastases. The actuarial 2-year and 5-year survivals of the 14 patients assessed were 64% and 56% respectively.

Adolescent↗

PubMed1979

Plasma volume changes during rest and exercise in different postures in a hot humid environment.

Plasma volume shifts were investigated in five male subjects who rested and exercised in the upright, low-sit, and supine postures in a hot humid environment (49.5 degrees C, 28.9 Torr). The resting and exercise periods were each 45 min in duration. Weight losses during rest were 0.3% with an additional weight loss of 1.1% during exercise. During exercise subjects worked at either 360 or 540 kpm.min-1 in each of three postures. Each experiment was preceded by a 30-min control period in the supine posture at an ambient temperature of 22 degrees C. At rest plasma volume was reduced 17.3% in the upright, 9.0% in the low-sit, and 2.2% in the supine postures (using the end of the supine rest as the zero reference point). Supine exercise resulted in a plasma volume decrease of 11%, the low-sit 7.1%, and the upright 2.7%. The total reduction in plasma volume during the rest and exercise period was 20% in the upright, 16.1% in the low-sit, and 13.3% in the supine. No significant differences in plasma volume shifts were observed between the high and low work loads. The results indicate that the plasma volume shifts observed during rest and exercise in the heat are qualitatively similar to those observed in a cool environment.

Adult↗

PubMed1978

Plasma volume changes with movement to supine and standing positions.

The chronology of hemoconcentration and hemodilution associated with changes in posture, and the reliability of venous hematocrit (Hct), hemoglobin (Hb), and plasma proteins (PP) as indicators in evaluating changes in plasma volume were determined in seven male subjects. Red cell mass was also measured by the CO method at the termination of the erect and supine positions. Movement to and from supine and erect positions produced consistent, rapid, and progressive changes in Hct, Hb, and PP. Thirty-five minutes in a supine position resulted in a 440-ml expansion of plasma volume. Resumption of the standing position resulted in an increase of 10.3 and 10.8% for Hct and Hb, respectively, and an increase in PP of 20.8%. A fluid efflux of 593 ml reduced blood and plasma volume by 9.5 and 16.2%, respectively. Red cell mass was unaffected by changes in posture. The significance of these postures on the reported alterations in plasma volumes consequent to the imposition of stresses on man are discussed.

Adult↗

PubMed1978

Maximal and submaximal exercise in different positions.

Maximal aerobic power tests on a treadmill and on a bicycle ergometer while sitting upright and in a low-sitting position were performed by seven males and five females. Treadmill max Vo2 for men and women combined was 4.0 and 11.2% higher compared to upright and low-sitting cycling, respectively. Maximal pulmonary ventilation, related respiratory measures, and heart rate were similar in all three tests. Submaximal work performed in the two cycling positions resulted in similar levels of oxygen uptake, ventilation, and heart rate. Work loads of 360 and 720 Kpm/min were performed by males with oxygen uptakes of 14.7 and 25.2 ml/kg . min, which corresponded to 30 and 52% of their upright-sitting maximal oxygen uptakes and to 33 and 55% of their low-sitting aerobic capacities respectively. Oxygen uptakes for work loads of 360 and 540 Kpm/min by females were 15.6 and 21.6 ml/kg . min, being equivalent to 42 and 58% of the maximal oxygen uptake in the upright-sitting, and to 43 and 60% in the low-sitting ergometer position, respectively.

Adult↗