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Biomedical subjects

H G Roggenkamp

Publications and source records attributed to H G Roggenkamp.

15 recordsLinked to original sources
PubMed1986

Effect of sex, age, body weight, and smoking on plasma viscosity.

The influence of age, sex, smoking, and body weight on blood plasma viscosity of a group of 639 healthy subjects was investigated in a randomized study. In order to determine the individual effects on a homogeneous collective of healthy subjects, all participants of this field study had to undergo physical examination, laboratory analysis, doppler sonography, and they were asked for a health history. The presence of disease or a disorder eliminated the participant from the study. Plasma viscosity was measured with the capillary tube plasma viscometer. Quality control according to clinical chemistry guidelines was conducted throughout the study to ensure the accuracy of the values measured being. It could be demonstrated that plasma viscosity is significantly elevated in healthy overweight subjects. However, a relationship between plasma viscosity and age, sex, and cigarette smoke inhalation could not be found.

Adult↗
PubMed1986

Erythrocyte rigidity in healthy patients and patients with cardiovascular disease risk factors.

The normal values for erythrocyte rigidity as measured by the "Selective Erythrocyte Rigidometer" were derived from a group of 275 apparently healthy subjects without risk factors. These individuals were randomly selected from an address book. The normal values ranged from 0.83-1.19 (median: 1.01). Quality control was conducted throughout the study and the analytical reliability was verified (day-to-day coefficient of variation VCd was 7.5%; coefficient of variation in series VCs was 3.1%). Inter- and intraindividual fluctuations in erythrocyte rigidity in the 8.3% and 6.1% ranges respectively were found in 20 apparently healthy subjects in the course of a 6-month study. No relationship was found between either age or sex and erythrocyte rigidity. Significantly higher erythrocyte rigidity values were found in patients with risk factors however; this applies to hypertensive patients, patients with diabetes mellitus, but also to apparently healthy subjects who were either overweight or smokers. Patients with disordered lipometabolisms on the other hand did not show any change in erythrocyte deformability when compared with healthy subjects.

Adult↗
PubMed1986

Hematocrit as a risk factor for vascular disease.

Besides the classical risk factors for vascular diseases, markedly elevated or reduced hematocrit values may also affect the course of circulatory disturbances. To find out an appropriate hematocrit for sufficient oxygen perfusion of the tissues, several studies have been conducted. Most of the surveys indicate that a hematocrit between 35% and 40% is the best solution. To achieve this aim by iso- and hypervolumetric hemodilution, a clinical double-blind trial with three substances, dextran 40, middle-molecular hydroxyethyl starch and isotonic saline solution was carried out. With regard to clinical results and the possible side effects of dextran middle molecular hydroxyethyl starch seems to be the best choice for hemodilution.

Animals↗
PubMed1986

[Determination of reference ranges of rheologic parameters: study of 653 randomly selected probands of the Aachen district].

To determine reference ranges for rheologic parameters (hematocrit, plasma viscosity, erythrocyte aggregation, erythrocyte rigidity) a randomized study involving 653 subjects was carried out. Conditions of sampling, transportation and storing of blood specimens were established prior to the survey. Only 283 subjects met the criteria for enrollment in the study; the others were rejected because of inconspicuous history, normal findings in physical and Doppler-sonographic examination and absence of the risk factors hypertension, diabetes mellitus, overweight, rheumatic diseases, and smoking. The reference range for hematocrit was determined by an impedance-measuring device to equal 39-52% for males and 34-50% for females. The reference range for plasma viscosity, measured by a capillary-tube-plasma viscometer, was found to vary from 1.14 mPas to 1.34 mPas. The reference values for the standardized erythrocyte aggregation index was determined with the mini erythrocyte aggregometer to range from 8 to 21. Erythrocytes measured with the selecting-erythrocyte rigidometer showed a rigidity reference range between 0.83 and 1.19. Analysis of the results revealed that the parameters were independent of age (except in young children) and sex (with the exception of hematocrit).

Age Factors↗
PubMed1984

Assignment of hemorheological instruments in the angiologic ambulance: first results and experiences.

Patients with chronic arterial disorders (CAD) frequently exhibit rheological alterations of the blood beneath generalisated sclerosing of the vessels and restricted arterial diameters. Alterations of different rheological parameters were determined in more than 80% of the examined patients. The following parameters were measured: yield shear stress in the ESM, hematocrit level in the IHA, plasma viscosity in the CTPV, standardized erythrocyte aggregation index in the MEA and standardized erythrocyte rigidity index in the SER.

Adult↗
PubMed1984

The erythrocyte-stasis-meter (ESM): a device to determine a universal parameter for the flow characteristics of blood.

A new experimental method is described which permits estimation of flow ability of blood: measuring the yield shear stress with the erythrocyte-stasis-meter (ESM). This method is based on the phenomenon that pathological blood under low pressure behaves like a solid body. Knowing the pressure difference at the transition point from solid to fluid behavior and the geometry of the channel, the yield shear stress can be calculated.

Aged↗
PubMed1984

The capillary tube plasma viscometer--an automatical instrument for measuring plasma viscosity.

A new capillary viscometer was developed to eliminate the measuring errors due to insufficient cleaning or the residue of cleaning solution in the capillary. A disposable polyurethane tube which can be discarded after each determination is used as a measuring chamber. This device has been constructed for bed-side application (light weight, dry, thermostat-controlled measuring capillaries, short measuring period, automated process, and easy operation). The PEARSON correlation coefficient for comparative measurements with the COULTER-HARKNESS viscometer was r = 0.979.

Adult↗
PubMed1984

A new device for the routine measurement of erythrocyte deformability.

We present a device for the routine measurement of the deformability of individual red blood cells, the so called Single-Erythrocyte-Rigidometer (SER). The time required for individual erythrocytes to traverse a single pore membrane (pore diameter = 5 micron, pore length = 25 micron) is taken as an index of red cell deformability. For example we present the results from patients with insult, polyneuropathy and morbus binswanger. Compared to the results of erythrocytes of healthy probands a significantly increased rigidity of the RBC of the patients can be diagnosed.

Equipment Design↗
PubMedDate not supplied

Production of single pore membranes for the measurement of red blood cell deformability.

For the determination of the deformability of individual red blood cells, a measuring device was developed, simulating the passage of individual red blood cells in capillaries of the nutritive microcirculatiuon. The kernel of this device, described here, is a single pore membrane 4--6 microns in diameter and 10 to 50 microns in length. The combination of a heavy ion accelerator (containing a faster shutter system) with nuclear tract technology makes possibly the manufacture of a large number of single pore membranes necessary for clinical and pharmaceutical tests.

Erythrocyte Membrane↗