Biomedical subjects
Publications and source records attributed to J B Garcia.
We describe a case of pseudo-xanthoma elasticum (PE) in a child with distinctive skin lesions without other symptoms. Renal ultrasonography showed a characteristic pattern of dotted increased echogenicity in the corticomedullary junction. Pancreas and spleen had similar echographic findings. We point out the importance of ultrasonography in the diagnosis of this rare disorder.
The urinary excretion of free amino acids was measured in 15 men who participated in a continuous airborne alert for an extended period of time. These men made up one of three teams which took turns so as to assure that at least one team remained airborne in an EC-135J aircraft at all times during the 96-h alert. The team making up the test group herein reported was airborne for 8.5 h on each of four successive days; flights were flown during the daytime. The data strongly suggest that the participants experienced anticipatory stress during the early part of the first two flight days of the alert, after which the excretion of amino acids was virtually unaltered. Additionally, amino acid excretion during the 24-h period following the alert was essentially in accord with baseline values established for another groups of subjects.
A biomedical appraisal of flight stress was made by means of a battery of urinary determinations on crewmen who participated in a 96-h airborne alert. The crewmen were divided into three teams, each consisting of 16 members and each manning an EC-135J aircraft. These teams took turns so as to assure that one team was airborne at all times during the alert; flights lasted either 8.5 or 12 h. Preflight baseline data were collected from only one of the three teams. Based on baseline and flight data obtained for that team, urea excretion correlated well with amino acid output which, in turn, correlated remarkably well with alpha-amino nitrogen output. These data collectively revealed the following flight effects: a) marked anticipatory stress immediately before the start of the airborne alert, b) marked flight stress late in each flight flown during the first 48 h, and c) adaptation to flight stress during the final 48 h.
As a feasibility study, two men were tested in a series of simulated flights which comprised a factorial experiment. Plysiologic data were collected during a 2-d baseline period, four 36-h experimental periods, and four recovery periods. The experimental conditions were as follows: a) uncomplicated simulated flight, b) flight complicated by extreme environmental dryness, c) flight complicated by mild hypoxia, and d) flight complicated by both dryness and -ypoxia. Throughout each flight the subjects alternately worked 2 h and rested 2 h, performing on psychomotor measuring devices during each work period. Five other men were studied under baseline conditions and during a 48-h simulated flight complicated by hypoxia. Urinary nitrogenous metabolites, including individual amino acids, were examined for sensitivity to the stressor complexes. Certain of the amino acids had high stressor sensitivity, tending to differentiate the effects of the single, double, and triple stressor complexes. They also differentiated the physiologic states in the experimental and recovery periods.
Among the methods of early diagnosis of rupture and trauma of the spleen, fixation of radioactive isotopes is one of the most interesting. An experimental study in the dog of B.M.H.P. metabolism, using B.M.H.P. labelled with Hg-203 and its rate of elimination by the kidney, gives information on lesions of the spleen, in particular, sub-capsular rupture. Splenic trauma reduces the capacity of uptake of mercury by this organ. Excretion in the urine then increases very definitely. This simple and inoffensive method should be used in man.
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The effects of dextran overload, norepinephrine drip and positive pressure ventilation upon right atrial, pulmonary wedge, left atrial and systemic arterial pressures were studied in 15 dogs. Rapid intravenous infusion of Dextran 70 invariably produced a marked and statistically significant (p < .001) rise in right atrial, pulmonary wedge and left atrial pressures. The rise in left atrial pressure invariably exceeded the rise in right atrial pressure, and the difference in maximum pressures averaged 10.8 mm Hg (p < .001). Thus acute fluid overload and pulmonary edema can be produced by rapid infusion of colloid solution in the absence of a marked rise in right atrial pressure, a point of considerable clinical importance. The rapid infusion of dextran produced a rise in systemic arterial blood pressure in all dogs so studied, though this rise was mild in some animals. This finding may explain in part the hypertension exhibited by patients in the recovery room who may have been overtransfused. A norepinephrine drip usually produced an increase in right atrial, wedge, left atrial and systemic arterial blood pressure (p < .01). When there was a significant rise in right atrial pressure and left atrial pressure, the maximum increase in left atrial pressure was always greater than the maximum increase in right atrial pressure (p < .005). This finding again emphasizes the fact that blood transfusion requirements cannot always be accurately assessed on the basis of right and left atrial pressure measurements when a vasopressor agent is being administered. Positive pressure ventilation increased both right and left atrial pressures, as expected. It was again confirmed that pulmonary wedge pressure, as measured with the Swan-Ganz catheter, is approximately equal to left atrial pressure over a wide range of induced variations. The Swan-Ganz catheter, introduced at the bedside in the intensive care unit when necessary, can provide highly useful information regarding left atrial pressure and left ventricular end-diastolic pressure.
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Basal insulin secretion stimulated by allogeneic lymphocyte injection was inhibited by SRIF, diazoxide and verapamil but was not affected by theophylline or imidazole. Glucose stimulated insulin secretion induced by alloantigens was inhibited by imidazole. Maximum insulin secretion was achieved with 2.1 mg/ml theophylline in allogeneized mouse pancreata and with 4.2 mg/ml in control pancreata. Propranolol also blocked allogen-induced glucose-stimulated insulin secretion. Phentolamine enhanced insulin secretion from both experimental groups, but phentolamine plus epinephrine only stimulated insulin secretion in control pancreata. Verapamil, diazoxide and SRIF diminished insulin secretion in both experimental groups. These results suggest that: a) basal insulin secretion induced by alloantigens may be mediated by an increase in calcium translocation, and b) glucose-stimulated insulin secretion induced by alloantigen may be mediated by a rise in B-cell cAMP.
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