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Biomedical subjects

E Haus

Publications and source records attributed to E Haus.

At least 91 records · Page 5Linked to original sources
PubMed1981

Heparin kinetics: variables related to disposition and dosage.

A method to determine heparin kinetics and dosage requirements was examined in 20 patients with active thromboembolic disease. Pretreatment heparin sensitivities were determined to establish the relationship between heparin concentration and activated partial thromboplastin times (APTTs). After an initial bolus dose, serial APTTs were measured, heparin concentrations were estimated, and kinetic determinations followed. Heparin elimination rate, distribution volume, and clearance were used to calculate dosage requirements. There was a 500% range in pretreatment heparin sensitivities. Smokers had more rapid heparin elimination rates and t 1/2s than nonsmokers did. Men had more rapid drug clearances than women did. Body weight was related to heparin dosage requirements. Patients treated early after onset of symptoms required higher doses than patients in whom treatment was delayed. A multiple regression model was developed for heparin dosage requirements from body weight, sex, delay between onset of symptoms and treatment, and smoking. This statistical model explained 78% of the variance in heparin requirements.

Adolescent↗
PubMed1981

Circadian host and tumor rhythms in Balb/C mice, rhythm induction in Harding-passey Melanoma.

The Harding-Passey melanoma in Bal/C or CD2F1 female mice shows, in light synchronized (LD12:12) undisturbed animals, no detectable circadian rhythm in cell proliferation as gauged by 3H-thymidine uptake in DNA. Manipulation of the animals and saline injection (.2 ml/20 gm), hydroxyurea injection (10 mg/ .2 ml/20 gm), and ACTH-17 (HOE 433) (.4 IU/ .2 ml/20 gm) induced a statistically significant circadian variation detected in several studies 4-24 and 16-36 hours after the treatment, only if the injection is given at the beginning of the light phase (LD12:12). Thus, tumor synchronization in this model is critically dependent upon the circadian stage of administration of the synchronizing agent. Endogenous and exogenous ACTH seem to be the synchronizing agent. Hydroxyurea in the dose given shows no additional effect.

Animals↗
PubMed1980

Seasonal (circannual) periodicity of spontaneous intracerebral hemorrhage in Minnesota.

Seasonal periodicity in the onset of spontaneous intracerebral hemorrhage was studied in 118 consecutive cases occurring during a six-year span. The patients were urban residents of eastern Minnesota, a region characterized by wide seasonal fluctuations in daylight and temperature. The greatest number of cases consistently occurred each year during January and February. Circannual (about one year) periodicity was demonstrated by statistical analysis using rhythmometric techniques. This periodicity coincided with that reported for mortality from cerebrovascular and cardiovascular diseases in the United States and elsewhere. Available information suggests that in populations at high risk for vascular diseases, climatic conditions might act as synchronizers to endogenous rhythms influencing the periodic occurrence of pathological vascular events.

Adult↗
PubMed1980

Differences and similarities among circadian characteristics of plasma renin activity in healthy young women in Japan and the United States.

A circadian rhythm of plasma activity (PRA) was demonstrated for both Japanese and North American women, the latter mostly Caucasians of mixed ethnic origin. The results were based on blood samples withdrawn at 4-hour intervals during a 24-hour span (in March 1978) from 20 subjects from Fukuoka (average age 20.4 +/- 0.1 years) and 16 subjects from Minneapolis (average age 20.2 +/- 0.4 years). The rhythms in the two populations showed similarities in some characteristics and differences in others. The timing of high values, i.e., of acrophases, objectively assessed by curve-fitting (and of corresponding 95 per cent confidence limits) was at 07(36) (05(00), 10(16) and 06(32) (03(00), 10(00) for Japan and USA, respectively. As objective measures of the extent of predictable rhythmic change mean amplitudes, in nanograms per milliliter per hour (ng/ml/hour), were similar (0.31 and 0.32); a statistically significant difference (P less than 0.05) was found in mean amplitudes expressed as percentage of the rhythm-adjusted average. Mean rhythm-adjusted average values (mesors) were lower in women from Japan than in those from the United States: (1.64 +/- 0.14 and 2.39 +/- 0.23 ng/ml/hour, respectively; P less than 0.01). A statistically significant difference in dietary salt, indicated by differences between the Japanese and North American women in the urinary excretion of sodium and chloride (P less than 0.05), almost certainly contributed to these results.

Adolescent↗
PubMed1980

Rhythm-adjusted age effects in a concomitant study of twelve hormones in blood plasma of women.

The concentrations of luteinizing hormone, prolactin, estrone, estradiol, 17-hydroxyprogestrone, cortisol, aldosterone, dehydroepiandrosterone, thyrotropic hormone, triiodothyronine, thyroxin and insulin were determined in blood plasma obtained from women aged 15 to 59 years. Blood was sampled at intervals of 20 to 100 min throughout 24-hour spans in each of the four seasons and (in the case of cycling women) in four different stages of the menstrual cycle. With such sampling allowing for rhythmic and other fluctuations over a broad time scale it was possible to demonstrate statistically significant effects of age on hormones associated with the menstrual cycle (luteinizing hormone, prolactin, estrone, estradiol and 17-hydroxyprogesterone) and on dehydroepiandrosterone, but not on the remainder. The amplitude of circadian rhythms in several of the hormones also varied with age, thus affirming the value of sampling throughout this particular rhythm.

Adolescent↗
PubMed1979

Circadian variation in urinary melatonin in clinically healthy women in Japan and the United States of America.

Urinary melatonin excretion is lower in East-Asian (Japanese) than in North-American (whites of mixed ethnic origin) women. Moreover, a statistically significant circadian rhythm is demonstrated by population-mean cosinor in the data pool from both groups of women. Furthermore, statistical significance characterizes interactions of effects from geographic differences (between ethnic groups) with temporal factors. Such spatio-temporal interactions await further scrutiny with a view inter alia of carcinogenesis as it is influenced by a spectrum of intermodulating rhythms.

Adult↗
PubMed1979

Effect of 18-h watch schedules on circadian cycles of physiological functions during submarine patrols.

Circadian rhythms of body temperatures, pulse rate, and respiration rate were measured in 11 subjects every 4 h during certain periods on two submarine patrols. Data on systolic and diastolic blood pressure were also obtained on five crew members during the first period. All the subjects of the first patrol were on an 18-h watch schedule (6 h on, 12 h off). During the second patrol, three subjects were on an 18-h watch schedule and three were on a 24-h watch schedule. Cosinor analysis for positive (P less than 0.05) detection of rhythm demonstrated that all subjects on the 18-h watch schedule developed 18-h cycles of body temperature, pulse rate, respiration rate, and systolic and diastolic blood pressure, which were then superimposed on the persisting 24-h cycles of the same function. The three subjects on a 24-h watch schedule did not show the 18-h cycles. Moreover, additional 12-, 36-, and 48-h cycles (harmonics and subharmonics of 24-h cycles) were found in all subjects on both patrols, attesting to the disintegration of circadian cycles under these conditions. Average sleep time tended to decrease toward the end of the patrol.

Body Temperature↗
PubMed1977

Survival and cure of leukemic mice after circadian optimization of treatment with cyclophosphamide and 1-beta-D-arabinofuranosylcytosine.

When cyclophosphamide and 1-beta-D-arabinofuranosylcytosine were administered to mice previously given injections of L1210 leukemia cells, the combination was more effective than either drug given alone. The effectiveness of the 2 drugs in combination was strongly influenced by the stage of the circadian system at which the drugs were administered. With the use of a chronobiological (sinusoidal) approach, in comparison with one or two conventional treatment schedules, it was possible to demonstrate an overall lower toxicity as monitored by death or weight loss. In general, mean survival times and cures (when obtained) were circadian stage dependent; for example, in 1 study the cure rate was 94% in mice treated at 1 circadian stage, but only 44% in those treated at another stage. It cannot be overemphasized, however, that just as the "right" timing can enhance (with statistical significance) both the tolerance to chemotherapeutic agents and the rate of cure in leukemic mice, so can the "wrongly" timed (wrongly placed) ara-C sinusoid or "wrongly" timed cyclophosphamide enhance toxicity and host death rate.

Animals↗
PubMed1976

Timing of single daily meal influences relations among human circadian rhythms in urinary cyclic AMP and hemic glucagon, insulin and iron.

Relations among circadian rhythms in serum iron, glucagon and insulin and urinary cyclic AMP excretion differ drastically when diurnally active, nocturnally resting human adults consume all daily food for one week as breakfast only and for another week as dinner only - a finding of interest to diverse fields, e.g., for optimizing certain kinds of therapy or for a better utilization of calories.

Circadian Rhythm↗
PubMed1976

Close reproduction by different laboratories of characteristics of circadian rhythm in 1-beta-D-arabinofuranosylcytosine tolerance by mice.

The tolerance of BALB/c X DBA/2 F1 mice to the popular cytostatic drug 1-beta-D-arabinofuranosylcytosine (ara-C) was tested in two laboratories about 1000 km apart. According to the same plan and on the same days in Little Rock, Ark., and Minneapolis, Minn., nine groups of 20 mice each received four courses of ara-C treatment, with 4-day intervals between them beginning February 7, 1973. In each course, a total dose of 240 mg/kg was divided among eight separate injections administered at 3-hr intervals. One group of mice received equal doses of ara-C every 3 hr (the homeostatic schedule). The eight other groups in each location received the same total dose per course but in gradually increasing and decreasing doses (the sinusoidal schedule). The timing of the highest doses on the latter schedule differed among the eight groups (by integer multiples of 3 hr). As predicted from earlier work, survival times after treatment with ara-C on different sinusoidal schedules differed drastically. However, the timing of the sinusoidal schedules yielding the longest survival was similar in the two locations. The survival times from all sinusoidal treatments from a given location were fitted by a 24-hr cosine curve. The timing of the rhythm in tolerance as a whole as thereby computed as the lag from local midnight of the peak in the cosine curve best fitting all data. The timing of this tolerance rhythm (briefly, circadian chronotolerance), computed separately for data from Arkansas and Minnesota, agreed within 1 hr. There also was close agreement in the results obtained by the 2 laboratories in mean survival time; the percentage of survivors when mice were treated according to certain of the selected sinusoidal schedules was much greater than for mice treated on the homeostatic schedule. This large and reproducible difference in tolerance and the similar timing of the overall fitted function describing chronotolerance in the hands of different investigators underlines the urgency of testing potential benefits from timed clinical treatment.

Animals↗