Experimental Malaria in Man. I. Physical Deterioration and Recovery 1

Henschel, Austin; Taylor, Henry L.; Keys, Ancel

doi:10.1172/jci102234

Cited by 9 publications

(6 citation statements)

References 11 publications

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“…After baseline measurements (see below) the volunteers were inoculated double-blindly at 9 a.m. on day 0. Seven subjects were given intravenously 0.5 ml of diluted (1 : 10 in sterile physiologic saline) human plasma from the same lot used to transmit sandfly fever in earlier studies (6,8). Two subjects were given 0.5 ml sterile isotonic sodium chloride to serve as controls.…”

Section: Methodsmentioning

confidence: 99%

“…The illness was monitored by measurements of rectal temperature every 2-6 hours. Temperature recordings were transformed into a fever index (sum of O F above lOOxduration in hours) (8). While febrile, the subjects were interviewed and asked to rate symptoms along a five-grade scale ( Table I).…”

Section: Measurementsmentioning

confidence: 99%

“…These findings along with virus and antibody titers and results of isometric and dynamic muscle performance tests (7) were correlated with clinical symptoms and signs. Sandfly fever was chosen because it is a highly reproducible mild virus infection characterized by acute onset of fever, it is accompanied by rather marked subjective symptoms including malaise, headache and myalgia in the acute phase, it lacks organ complications and is typified by a rapid recovery (8). The predictable course allowed results from the fever phase to be compared with those from early convalescence when the cumulative nitrogen-losing consequences of accelerated muscle protein catabolism are most marked (8).…”

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confidence: 99%

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Does Fever or Myalgia Indicate Reduced Physical Performance Capacity in Viral Infections?

Friman

Wright

Ilbäck

et al. 1985

Journal of Internal Medicine

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To study prospectively the effects of a brief febrile viral infection on parameters of muscle and circulatory function, seven volunteers were inoculated with sandfly fever virus and two control subjects with sterile saline. During but not after fever, decreased isometric and dynamic strength and endurance were recorded in various muscles. Impairment could not be explained by altered activities of relevant muscle enzymes in serum or muscle tissue or by altered muscle ultrastructure, but correlated with the severity of perceived symptoms, including myalgia, as rated by each subject. Compared to baseline, cardiac stroke volume was lower during and after fever. During fever, an increased heart rate maintained cardiac output at pre‐inoculation values, whereas cardiac output fell in early convalescence. This decrease in cardiac output correlated significantly with the severity of fever. Thus, in brief viral infections a transient impairment of muscle performance capacity is correlated to subjective symptoms such as myalgia, rather than to fever, whereas a decreased cardiac output following such infections seems to be associated with the fever reaction.

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Section: Methodsmentioning

confidence: 99%

Section: Measurementsmentioning

confidence: 99%

mentioning

confidence: 99%

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Does Fever or Myalgia Indicate Reduced Physical Performance Capacity in Viral Infections?

Friman

Wright

Ilbäck

et al. 1985

Journal of Internal Medicine

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“…The general characteristics of the subjects and the experimental program were described in a preceding paper (2). The 12 volunteer subjects were Conscientious Objectors who were considered to represent well-nourished normal young men in a fair state of physical fitness.…”

Section: Subjects and Programmentioning

confidence: 99%

Experimental Malaria in Man. Ii. Liver Function 1

Keys¹,

Wells²,

Hoffbauer³

et al. 1950

J. Clin. Invest.

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It is generally known that malaria may produce signs of impaired liver function. In studies on experimentally induced malaria in this laboratory (1, 2), special efforts were made in an attempt to obtain information on four aspects of the question as to the effects on the liver: (1) The magnitude and character of the impairment as indicated by the several methods customarily used in the study of liver disease; (2) the time course of change during continuance of the infection; (3) the relationship of the liver function to the body temperature; (4) the recovery course following termination of the malaria with quinine. The present paper summarizes the findings on these points. SUBJECTS AND PROGRAMThe general characteristics of the subjects and the experimental program were described in a preceding paper (2). The 12 volunteer subjects were Conscientious Objectors who were considered to represent well-nourished normal young men in a fair state of physical fitness. Prior to the experiment, emphasis was placed on discovering any indications of previous episodes or history of liver disease. One subject (No. 9) gave a history of illness at the age of 12 which was characterized by an insidious onset with fever, malaise and jaundice of two months' duration, with subsequent full recovery without evidence of residues. Two other subjects had occasionally noted mild indigestion after eating fatty foods. There were no other suggestive points in the histories and no physical abnormalities were found on physical examination. In five subjects the liver could not be palpated. In seven subjects the liver was palpated at the right costal margin on deep inspiration and was apparently of normal texture; the liver was not tender in any of the men.For three weeks before inoculation the subjects were housed and fed in the laboratory on a standard regimen of moderate activity and a standard "good" diet of 3,600 Cal. with (5, 6); previous experiences with this procedure in inoculation malaria have been described (7,8). Urine was analysed for bilirubin with the Harrison strip test (9) and the methylene blue test (10). In a series of control studies it was found that heparinized plasma gave results identical with those obtained on serum for both prompt and total bilirubin and was more satisfactory than either oxalated or citrated plasma. A few trials with freezing plasma and urine samples indicated that subsequent analyses for bilirubin did not agree closely with the results of analyses on the fresh materials so attempts at storage were abandoned. Accordingly, all bilirubin analyses were made on the fresh materials.For the bromsulfalein excretion test a dosage of 5 mg. per kg. of body weight (11) and a 45-minute time interval (12) were employed.Cephalin-cholesterol flocculation was estimated according to Hanger (13), readings being made at 24 and at 48 hours. The thymol turbidity reaction was estimated with Maclagan's method (14).Urobilinogen was estimated with the method of Watson et al. (15,16) in urine samples collected over twohour peri...

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“…Besides the usual resting ECG, the response of the ECG to the upright posture was studied. The subjects and conditions have been described in a previous paper (3).…”

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confidence: 99%

Experimental Malaria in Man. Iii. The Changes in the Electrocardiogram 1

Simonson¹,

Keys²

1950

J. Clin. Invest.

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Electrocardiograms (ECGs) taken from patients with malaria are usually within normal limits or show only minor non-specific deviations. This is not evidence that changes do not occur or that the malarial process is without effect on the heart. The normal limits of the several ECG items are so wide, and are extending with the accumulation of more extensive data (1, 2), that definite and significant changes in an individual may occur without resulting in an ECG which by itself would be classified as abnormal. Obviously "before and after" studies are required.The present report covers the ECG findings on 12 previously healthy young men before experimental blood-induced vivax malaria and on two occasions following the termination of the disease. Besides the usual resting ECG, the response of the ECG to the upright posture was studied. The subjects and conditions have been described in a previous paper (3). METHODSThe three standard limb leads were recorded after a rest of at least ten minutes in the supine position on the tilt-table, the subject being clamped by the hips using Mayerson's (4) arrangement. The table was then tilted to an angle of 680 and the ECG recordings were repeated during the first, fifth and tenth minute with the subject passively supported in this relatively upright position. All tests were made in the morning before breakfast Control studies made several months before malaria were compared with repetitions on the second day and again three weeks after termination of the malaria.The following ECG items were measured and analysed: Durations of P, QRS, P-R, and Q-T; the "constant" KQT (QT divided by the square root of R-R); the amplitudes in each lead of P, QRS, and T; the sums for the three leads of the amplitudes of QRS and of T ( 'sounds, the duration of mechanical systole was estimated (interval between first and second sounds), and K,,t was calculated as the quotient of this divided by the square root of the R-R interval. Since neither the QRS interval nor the amplitude or duration of P showed significant responses to malaria, they are not considered in the presentation of results below. RESULTS In supine restThe findings in standard (basal) rest are summarized in Table I. The majority of the electrocardiographic items showed some change when they were recorded on the second day following the termination of malaria and these changes were statistically significant at the 5 per cent level for the P-R interval (slightly lengthened), for the sum of the QRS potentials in the three leads (increased), for T2 (reduced but still positive), and for the angle of the QRS axis (small left axis shift). There was a more significant decline in the sum of the potentials of the T waves in the three leads (ET); the data indicate such a change could be expected by chance alone in less than one trial out of 100 (i.e., p. = 0.01).Three weeks after the termination of malaria some of the items had regressed toward the control but there were still some significant differences. The slight elevation of the heart rate ...

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Experimental Malaria in Man. I. Physical Deterioration and Recovery 1

Cited by 9 publications

References 11 publications

Does Fever or Myalgia Indicate Reduced Physical Performance Capacity in Viral Infections?

Does Fever or Myalgia Indicate Reduced Physical Performance Capacity in Viral Infections?

Experimental Malaria in Man. Ii. Liver Function 1

Experimental Malaria in Man. Iii. The Changes in the Electrocardiogram 1

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