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Biomedical subjects

C G Kramer

Publications and source records attributed to C G Kramer.

12 recordsLinked to original sources
PubMed1994

Effects of supine blood pressure on interpretation of standing up test in 500 patients with diabetes mellitus.

The relationship between fall in blood pressure (BP) on standing and supine BP before standing up was studied in 75 healthy controls and in 500 patients with diabetes mellitus (DM) using conventional BP measurements. The influences of physiological (sex, age, height) and DM-related factors (type, duration, HbA1c-level, use of insulin, oral antidiabetic and anti-hypertensive medication) on BP-fall were assessed. The effects of using a fixed abnormality threshold and a new supine BP-related abnormality definition on interpretation of the test were determined. Highly significant relationships of BP-fall with supine BP were found in control and DM subjects. Slopes did not differ between these groups. Slopes for systolic BP-fall were steeper in type 1 than in type 2 DM patients. A forward stepwise regression procedure revealed that supine BP (explaining 24% of variance) and HbA1c (explaining 1%) had significant influences on systolic BP-fall. Diastolic supine BP explained 14% of diastolic BP-fall, age 3%, and sex 2%. Only supine BP was thus of practical relevance in explaining BP-fall. Taking supine BP into consideration affected test results: of 74 subjects with an abnormal conventional systolic BP-fall, 10 (13.5%) had been misclassified according to the new method, and 4 additional patients had been misclassified as normal. Classification changes were much larger for diastolic BP-fall (63% of conventionally abnormal results were reclassified as normal), but the range of diastolic BP is smaller than for systolic BP, meaning that the measurement error interferes with its clinical utility.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1993

Where to record motor activity: an evaluation of commonly used sites of placement for activity monitors.

The aim of this study was to evaluate the role of the site of attachment of activity monitors. We compared mean diurnal and nocturnal motor activity measures as well as the daily pattern of motor activity of dominant and non-dominant wrist recordings over 5 successive days of 10 healthy right-handed and 10 left-handed subjects. In a second study we evaluated the relationship between truncal motor activity and wrist motor activity. No differences emerged between the diurnal and nocturnal measures as well as the diurnal activity pattern of the dominant and the non-dominant wrist. Additionally, no differences were found in relation to handedness. Our results show that it is inaccurate to regard wrist motor activity measurements as representative of an invariable percentage of truncal motor activity; the relation between the measurements of these two recording sites varies across the daytime period. During the nocturnal period bilateral wrist motor activity occurred frequently in absence of truncal motor activity. The reverse situation, however, may occur sporadically. This finding most likely reflects that integrated generalized movements like postural shifts are measured at all recording sites, while the small movements that occur at the distal extremities are predominantly recorded by wrist-worn monitors. In conclusion, it is apparent that for both diurnal and nocturnal studies on the assessment of motor activity, either wrist can be chosen as the recording site. Across the diurnal period the relation between motor activity recorded at the wrist and waist is subject to considerable variability.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Long-term sleep deprivation as a game. The wear and tear of wakefulness.

We report here the first sleep deprivation study done on a group of 5 healthy students (1 female, 4 males, 23-24 years of age) while playing a game (Triviant). In 2 persons an EEG was recorded for 6 consecutive 24 h periods with an ambulatory monitor from the baseline night until 72 h after deprivation. The baseline night showed normal hypnograms. The students were deprived of sleep for 65 h following the baseline night. Sleep deprivation was complete and resulted in bradyphrenia, loss of memory and contact with reality, ataxia, decrease in body temperature and loss of body weight. The main sign of recuperation was a strongly increased slow-wave sleep synchronization during the first recuperation period (day-time sleep) only. There were no signs of REM rebound.

Adult↗
PubMed1992

Non-invasive assessment of autonomic nervous function in Gilles de la Tourette syndrome.

Autonomic nervous function was investigated in 18 Gilles de la Tourette (GTS) patients and in 23 controls, who matched the patients in age, sex, baseline blood pressure and baseline heart rate. Four heart rate tests were used (variation at rest, during deep breathing, following standing up and during a Valsalva manoeuvre), and two blood pressure tests (standing up and sustained handgrip). The only significant difference between the groups was found in the Valsalva test. This was due to the initial heart rate increase which was higher in the GTS group; the subsequent decrease did not differ between the groups. Increased sympathetic activity is a possible explanation for this finding, but no additional evidence in its favour was found. No signs of autonomic failure were found.

Adolescent↗
PubMed1991

Autonomic nervous system tests depend on resting heart rate and blood pressure.

In order to study the effects of baseline blood pressure and heart frequency on autonomic function tests, 75 normal subjects (aged 8-96 years) were investigated. Heart rate variability was studied at rest, during deep breathing, following standing up and during a Valsalva manoeuvre. Blood pressure changes were recorded during standing up and during sustained handgrip. Responses were described as ratios and as differences to study the efficacy of both methods. Multiple regression analysis showed that significant relationships with the resting heart rate existed for ratios but not for differences. The blood pressure rise in the sustained handgrip test showed a significant relationship with resting blood pressure regardless of the description method. As expected, relationships with age existed for all four heart rate tests regardless of the description method. The blood pressure responses were not significantly related to age. We advise that heart rate test results should be presented as differences, as this avoids the need for correction for the resting heart rate. Correction for the resting blood pressure improves the accuracy of the standing up blood pressure test. Correction for age remains necessary for heart rate tests but not for blood pressure tests.

Adolescent↗
PubMed1988

Autonomic nervous function in Huntington's disease.

Autonomic nervous system function was studied by means of a series of standardized tests in 11 patients with Huntington's disease (HD) and in 11 age- and sex-matched controls. Two statistically significant differences were found. The blood pressure response to sustained handgrip was diminished and the pupillary light reflex latency was increased in the HD group. The former probably reflects diminished input from higher centers on an otherwise intact sympathetic nervous system. The latter may indicate involvement of the pretectal or Edinger-Westphal nuclei in HD. No further signs of autonomic nervous system dysfunction were found.

Adult↗
PubMed1967

Chlorine.

Explore the source record for details and available documents.

Chlorine↗
PubMedDate not supplied

Health of workers exposed to 1, 1, 1,-trichloroethane: a matched-pair study.

An epidemiologic study of 151 matched pairs of employees was conducted in two adjacent textile plants, one of which used inhibited 1,1,1-trichloroethane as a general cleaning solvent. Employees in the study population had exposures to the solvent for 6 yrs or less at varying concentrations which were measured by breathing zone sampling and personal monitoring. While cardiovascular and hepatic observations were of primary interest, other health parameters were also studied. Application of sensitive statistical techniques and careful examination of all data did not reveal any clinically pertinent findings that were associated with exposure to 1,1,1-trichloroethane. The statistically significant associations that were observed between health measures and nonexposure factors emphasize the need to consider age, sex, race, and other variables in designing epidemiologic studies.

Adolescent↗