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Biomedical subjects

B Friedmann

Publications and source records attributed to B Friedmann.

At least 19 recordsLinked to original sources
PubMed1998

[Diagnosis of performance capacity and guided training for physical endurance].

The evaluation of the aerobic capacity is of great importance for athletes as well as for patients with cardiac and pulmonary diseases. For objective measurements of cardiorespiratory and metabolic responses heart rate, lactate concentration in capillary blood and ventilatory gas exchange are determined during incremental exercise tests either on different ergometers in a laboratory or under training conditions in the field. Besides the maximal O2-uptake (VO2max) several ventilatory and lactate thresholds have been proposed as reliable values for assessing the aerobic capacity and giving training recommendations. For interpretation of the results the training and nutrional behaviour in the previous days have to be considered as especially the lactat thresholds are influenced by the glycogen content of the muscles. Furthermore, training recommendations cannot always be easily transferred from test to training conditions as these can be very different from each other.

Energy Metabolism↗
PubMed1998

[Pseudo-anemia caused by sports].

Regular physical training leads to an increase of plasma volume by 10-20 percent. Therefore, hemoglobin concentration slightly below normal values in the presence of low-normal serum ferritin levels in athletes are usually due to a dilutional "pseudoanemia". Several cross sectional studies indicate that true iron deficiency anemia is not more frequent in athletes than in the general population. Since regular physical activity, especially extensive, running increases iron loss, mild iron deficiency (abnormal serum ferritin and normal hemoglobin concentration) and sometimes true iron deficiency anemia can occur especially when nutritional iron intake is insufficient and iron demand is increased because of growth (children, adolescents) or additional iron loss (menstruation). Several controlled studies indicate that iron supplementation (recommended dose 2 x 100 mg elementary iron/day) improves performance only when hemoglobin concentration increases, i.e. when iron deficiency anemia is present. On the contrary, iron supplementation has no measurable effects on performance when hemoglobin concentration cannot be increased, i.e. in mild iron deficiency.

Adolescent↗
PubMed1997

[The importance of iron in humans].

The authors submitted a very brief review of some biological properties of iron in particular protein-bound iron and on the immense amount of iron which surrounds us (it is the fourth most frequent element). In the human organism there is no physiological system for iron elimination. Therefore its absorption is regulated and restricted. Some substances promote its absorption, other inhibit it. An important factor in the regulation of iron absorption are the iron reserves of the organism, the amount of dietary iron and the enhanced erythropoiesis (incl. the ineffective one), while reduced erythropoiesis does not affect iron absorption. Ascorbic acid forms chelates with iron and thus remains soluble and can be absorbed despite the alkaline pH in the duodenum. Unbound trivalent iron remains insoluble. An important asset to rational iron therapy are Lauberger's discovery of ferritin (1936), assessment of the iron plasma level (Heilmeyer and Plötner, 1937), Laurell's discovery of transferrin (1947), and Addison's RIA method for assessment of the serum ferritin level (1974). Sideropenia remains the most widespread deficiency in human pathology, sideropenic anaemia the most readily diagnosed anaemia which is, however, most wrongly treated.

Humans↗
PubMed1997

[Hypercalcemia as the first manifestation of bone marrow T-cell lymphoma].

The authors describe the case of a 20-year-old patient where the first leading symptom was hypercalcaemia. A similar case was not published so far in the Czech literature. The disease took a fulminant course and proved fatal nine days after the first symptoms of the disease. The correct diagnosis was established only by necropsy. The adverse course of the disease could not be influenced by repeated haemodialysis nor by the administration of disodium pamidronate (Aredia) and calcitonin. The authors discuss differential diagnostic problems of hypercalcaemias and the pathogenesis of hypercalcaemia in malignant diseases of the haematopoietic system.

Adult↗
PubMed1997

[High altitude training: sense, nonsense, trends].

Athletes who need high endurance capacity often use training at moderately high altitude (1500-3000 m) to improve oxygen delivery and utilization because of a hypoxia-induced increase of the red blood cell volume and adaptations at the muscular level. As maximal heart rates decrease at high altitude and plasma lactate levels for a given workload change during prolonged exposure to high altitude, it can be difficult to control and adapt the intensity and duration of the work-outs. Furthermore, maximal performance capacity decreases and therefore training intensity at high altitude is usually reduced compared to training at sea level. To avoid these disadvantages at high altitude a concept of living at moderately high altitude and training at lower elevations, termed "live high-train low" evolved, opposing the conventional concept of "live high-train high". A third option using a hypobaric chamber ("live low-train low") is hardly used anymore for training athletes. Studies on the effects of conventional high-altitude training for the improvement of athletic performance often lack a rigorous controlled design and yield controversial results. Regarding the new concept of "live high-train low" there is only one controlled study on college athletes and it shows a minor advantage of this new approach compared to conventional high-altitude training. However, training concepts are especially important for elite competitive athletes, and controlled studies with such individuals are very difficult to perform. Therefore, it appears that today we cannot answer the question of whether altitude-specific physiologic factors or non-altitude-related benefits of training camps account for the success of individual athletes.

Altitude↗
PubMed1997

Decreased plasma glutamine level and CD4+ T cell number in response to 8 wk of anaerobic training.

The purpose of the present study was to investigate the role of plasma amino acids and glutathione (GSH) on the absolute number of leukocyte and lymphocyte subpopulations in response to different training programs. Healthy untrained subjects were randomly assigned to an 8-wk aerobic (AET) or anaerobic (ANT) exercise training program. Absolute number of cell counts did not significantly change in AET, whereas a decrease of CD4+ T cell counts (P < 0.05), a fall in cells expressing CD45RA+ antigen (P < 0.05), and a marked increase in CD8+ T cell numbers (P < 0.01) were noted in ANT at the end of the training period compared with baseline values. Furthermore, ANT demonstrated a marked rise (P < 0.001) in plasma glutamate from 27.6 +/- 2.8 to 49.8 +/- 5.2 microM and a considerable reduction (P < 0.001) of the plasma glutamine pool from 713 +/- 22 to 601 +/- 30 microM after 8 wk of training. The decrease in glutamine showed a strong positive correlation to the individual loss of CD4+ T cells (r = 0.67, P < 0.001). AET demonstrated a rise (P < 0.05) in GSH from 20.7 +/- 2.5 to 28.1 +/- 1.5 nmol/mg protein at terminal examination. In conclusion, our data indicate impairment of the number and activity of CD4+ T cells in response to 8 wk of ANT, which might be linked to metabolic factors such as glutamine.

Adult↗
PubMed1996

Low plasma glutamine in combination with high glutamate levels indicate risk for loss of body cell mass in healthy individuals: the effect of N-acetyl-cysteine.

Skeletal muscle catabolism, low plasma glutamine, and high venous glutamate levels are common among patients with cancer or human immunodeficiency virus infection. In addition, a high glycolytic activity is commonly found in muscle tissue of cachectic cancer patients, suggesting insufficient mitochondrial energy metabolism. We therefore investigated (a) whether an "an-aerobic physical exercise" program causes similar changes in plasma amino acid levels, and (b) whether low plasma glutamine or high glutamate levels are risk factors for loss of body cell mass (BCM) in healthy human subjects, i.e., in the absence of a tumor or virus infection. Longitudinal measurements from healthy subjects over longer periods suggest that the age-related loss of BCM occur mainly during episodes with high venous glutamate levels, indicative of decreased muscular transport activity for glutamate. A significant increase in venous glutamate levels from 25 to about 40 microM was seen after a program of "anaerobic physical exercise." This was associated with changes in T lymphocyte numbers. Under these conditions persons with low baseline levels of plasma glutamine, arginine, and cystine levels also showed a loss of BCM. This loss of BCM was correlated not only with the amino acid levels at baseline examination, but also with an increase in plasma glutamine, arginine, and cystine levels during the observation period, suggesting that a loss of BCM in healthy individuals terminates itself by adjusting these amino acids to higher levels that stabilize BCM. To test a possible regulatory role of cysteine in this context we determined the effect of N-acetyl-cysteine on BCM in a group of subjects with relatively low glutamine levels. The placebo group of this study showed a loss of BCM and an increase in body fat, suggesting that body protein had been converted into other forms of chemical energy. The decrease in mean BCM/body fat ratios was prevented by N-acetyl-cysteine, indicating that cysteine indeed plays a regulatory role in the physiological control of BCM.

Acetylcysteine↗
PubMed1995

[Type I cryoglobulinemia].

HISTORY AND CLINICAL FINDINGS: For 2 years a 52-year-old man had repeated bouts of purpura, arthralgia and fever. He was known to have abnormal monoclonal gammaglobulins, type IgG-lambda and vasculitis when he had another bout with acute renal failure and necrotizing ulcers in the legs. TESTS: Several laboratory tests were abnormal: erythrocyte sedimentation rate (122 mm), haemoglobin level (9.1 g/dl), white cell count (32,000/microliters), platelet count (562,000/microliters), creatinine level (4.1 mg/dl) and liver enzyme activities. He also had proteinuria (4.5 g daily) and nephritic urinary sediments. The immunoglobulin was subtype IgG3, and a cryoglobulinaemia was also present. Total complement level (CH 50) was not measurable. Bone marrow aspirate revealed plasmocytoma infiltration, and renal biopsy demonstrated necrotizing arteritis, as well as granular subendothelial deposits of IgG and complement. TREATMENT AND COURSE: After three plasma separations and initiation of the first treatment cycle with a four-day infusion of vincristine, doxorubicin and dexamethasone the creatinine concentration fell to within the normal range and the necroses healed slowly. No cryoglobulin activity has been demonstrable over the past 24 months.

Acute Kidney Injury↗
PubMed1995

Lymphocyte subpopulations and concentrations of soluble CD8 and CD4 antigen after anaerobic training.

In 13 middle-aged, moderately trained men (40-60 yr) we investigated the influence of anaerobic training on immunological parameters measured at rest. The 4 week anaerobic training program (two 30-min sessions weight lifting and one interval training per week; lactate levels 4-6 mM and 8-10 mM, respectively), caused a significant increase of the mean arm muscle force by 7% (handgrip test, p < 0.05). Evaluation of lymphocyte subsets was performed by means of three-colour immunofluorescence analysis (FACS). After 4 weeks of training we found a significant reduction of the CD4+ T-cell counts by 15% (p < 0.05) paralleled by a fall of naive cells (CD3+/CD4+/CD45RA+) by 16%, which, however, was statistically not significant. While percentages of CD3+ lymphocytes decreased significantly by 6% (p < 0.001), absolute numbers of CD3+ T-lymphocytes were not detectably affected and also the relative ratio of CD8+ T-cell subsets, i.e. the ratio of suppressor vs cytotoxic T-cells (CD3+/CD8+/CD11b+, CD3+/CD8+/CD11b- respectively) remained unchanged. Likewise the serum concentrations of the soluble CD8 and CD4 antigen (sCD8/sCD4) as determined by sandwich enzyme immunoassays were found to be unaffected. We conclude that 40-60 years old healthy human subjects performing anaerobic training experience on average a significant decrease of circulating CD4+ T-lymphocytes, while other parameters including the activation parameters sCD8 and sCD4 remained unchanged.

Adult↗
PubMed1995

Balanced activation of coagulation and fibrinolysis after a 2-h triathlon.

To examine whether exercise-induced thrombin formation is accompanied by increased in vivo plasmin formation, we measured molecular markers and neoantigens of the hemostatic system in 10 male subjects (mean 29 yr. range 19-38) before, immediately after, and 2, 8, and 21 h after a triathlon lasting 128-163 min. Thrombin-antithrombin (TAT) complexes, fibrinopeptide A (FPA), and tissue plasminogen activator (t-PA) antigen were maximally increased immediately after exercise and decreased thereafter rapidly. Prothrombin fragment 1 + 2 (PTF1 + 2), fibrin degradation products (FbDP) and plasmin-antiplasmin (PAP) complexes rose to a similar extent 0 and 2 h after exercise decreased thereafter. The maximal levels of PTF1 + 2, TAT, FPA, and FbDP were 1.5-, 2.1-, 1.8-, and 1.9-fold above baseline, respectively. This investigation shows that strenuous prolonged exercise leads to a moderate activation of blood coagulation resulting in thrombin and fibrin formation which is accompanied by a greatly enhanced plasmin generation. It is concluded that the hemostatic of healthy individuals is well kept in balance when stimulated by prolonged strenuous exercise.

Adult↗
PubMed1994

Plasma and platelet catecholamine and catecholamine sulfate response to various exercise tests.

We tested the hypothesis that platelet and plasma catecholamine sulfates (CA-S) and platelet catecholamines (CA) reflect the overall sympathoadrenergic activation by exercise of 1 h duration. Ten well-trained subjects performed a low-intensity [62% maximum O2 consumption (VO2max); LI] and a high-intensity exercise test (77% VO2max; HI) and two tests at a similar average power output that consisted of 20 min at 77% VO2max and 40 min at 62% VO2max (HI/LI) and vice versa (LI/HI). Plasma norepinephrine sulfate (NE-S) increased to higher levels after HI than after LI exercise (15.5 +/- 2.1 vs. 8.9 +/- 0.7 nmol/l). Immediately after HI/LI and LI/HI plasma NE-S was similarly increased (9.59 +/- 1.1 vs. 9.96 +/- 1.3 nmol/l), whereas norepinephrine was higher after LI/HI than after HI/LI (23.0 +/- 3.2 vs. 15.7 +/- 2.3 nmol/l). Platelet CA and CA-S were increased only after HI. In conclusion, the plasma NE-S response to exercise parallels the overall sympathetic activation. These results support the hypothesis that plasma NE-S measured immediately after exercise reflects the overall sympathoadrenergic activity over prolonged periods of exercise. Platelet CA and CA-S poorly reflect sympathoadrenergic activation.

Adult↗
PubMed1994

[Trephine biopsy of the bone marrow in hematologic tumors].

A group of 1000 random trephine biopsies were evaluated according to their usefulness for typing and staging of haematological tumours. Trephine biopsy contributed someway to clinical data in half the cases. Primary medullary processes showed an excellent correspondence of clinical and bioptical data. Biopsy contributed substantially to specification of myeloproliferations and myodysplasias. There were only 24% of negative results (descriptive inconclusive). Malignant lymphomas presented situation analogical to leucaemias. Peripherical malignant lymphomas in medulla mostly did not follow diversity of lymph node phenomena and did not contribute to more detailed typing but enabled satisfactory staging. Malignant lymphomas were located, unlike leucaemia, intertrabeculary or peritrabeculary and often induced reactive myeloproliferation or scarring. Biopsy was usually good for separation of medullary carcinosis. Remarks to technology of getting and processing of bioptical sample were discussed.

Biopsy↗
PubMed1991

[Prognostic factors in non-Hodgkin's malignant lymphoma].

A group of 271 patients with non-Hodgkin's malignant lymphomas from years 1975-1989 was tested using multivariant statistical analysis, from the point of view of the prognostic value their basic clinical and laboratory data. In the group of low grade malignancy lymphomas, the following factors showed a prognostic validity: clinical stage, general status, centrocytic histological subtype, and anaemia. In the group of high grade malignant lymphomas following one were set as prognostically important: general status, clinical stage and age. In particular histological subtypes of low grade malignancy statistically valid difference of survival was not proved, the centrocytic type excluded. However, the difference was found between these types and particular subtypes of high malignancy grade. Based on these results, the Cox's risk model was made, enabling us to define 4 risk groups according to the histological subtype and clinical stage: group A (risk less than 0.5), group B (risk = 0.5-1.0), group C (risk = 1.0-2.0), group D (risk greater than 2.0).

Female↗
PubMed1991

[A diagnostically difficult case of hairy cell leukemia with ring-shaped nuclei].

We observed a case of hairy cell leukaemia without splenomegaly and without hairy cells in blood that was difficult to diagnose. Typical hairy cells with cytoplasmic projections were found in hypocellular bone marrow smears rarely whereas atypical mononuclear cells of hairy cell type constituted 70% and 1.5% of them exhibited ring-shaped nuclei. These cells were in 8% positive for tartrate-resistant acid phosphatase. Bone marrow biopsy revealed diffuse infiltration with hairy cells. We reviewed bone marrow smears of 11 other patients with hairy cell leukaemia and we found hairy cells with ring-shaped nuclei in one of them only with a frequency of one promile.

Bone Marrow↗
PubMed1990

Biphasic voltage relaxation pattern observed in cells of Eremosphaera viridis after injection of charge-pulses of short duration: detection of tip clogging of intracellular microelectrodes by charge-pulse technique.

Charge pulse experiments performed on the peat-bog alga Eremosphaera viridis revealed an unusual voltage relaxation behaviour. Injection of charge pulses of 1 microseconds duration resulted in an immediate charging of the membranes (time constant of the order of 40 ns). Nevertheless, the potential-measuring microelectrode recorded an exponential increase in membrane voltage with a time constant of about 1.3 ms. The maximum voltage value was recorded after about 3 ms, followed by an exponential decay with a time constant of about 9.6 ms. This biphasic time course was independent of the amplitude of the injected charge and of the location of the impaled microelectrodes in the vacuole. Centrifuged cells in which the chloroplasts and the other organelles were pelleted in one part of the cells showed the same electrical response. Electrical breakdown of the cell membranes resulted in the disappearance of the biphasic voltage response. In this case only the decaying relaxation process could be recorded with a time constant of 3 ms. After resealing of the membranes the original biphasic relaxation response was restored. Increasing concentrations of KCl in the bathing medium reduced both time constants almost correspondingly. The experimental findings were evaluated with an electrical equivalent circuit. Theoretical analysis with reference to the experimental data suggested that the delayed voltage response of the potential-recording electrode resulted from a membrane seal across the tip of this electrode. The resistance of this seal was calculated to be about 400 M omega. The specific resistances and capacitances of tonoplast and plasmalemma membranes were calculated from the decaying part of the biphasic relaxation curves. The average values were found to be 2.58 omega.m2 and 5 mF.m-2. The investigations reported here suggest that charge pulse experiments can be generally used for the detection of membrane and cytoplasmic material clogging of the tip of intracellular microelectrodes, a problem with which most electrophysiologists are faced when interpreting data obtained from impaled microelectrodes.

Cell Membrane↗
PubMed1990

Examination of serum ferritin and erythrocyte ferritin--its role in the blood transfusion service.

Blood donors were examined for serum ferritin values and concentration of ferritin in the erythrocytes. The group of male and female donors without previous donations showed average values of 102.27 ng and 51.75 ng of ferritin per one ml of serum, respectively. Males with over 20 donations had 68.04 ng ferritin per one ml, females 37.14 ng of ferritin per one ml. The reduced serum ferritin values in multiple male and female donors is statistically significant. Serum ferritin values in women of the two groups are lower than those of males, the difference also being statistically significant. In male and female blood donors, irrespective of the number of donations, average values of 13.74 ag and 12.07 ag of ferritin per erythrocyte, respectively, were established. The difference in ferritin concentration in the erythrocytes between males and females is statistically insignificant. The correlation coefficient failed to demonstrate any dependence between erythrocyte ferritin concentration and concentration of ferritin in the serum. The object of serum ferritin determination in blood donors is to detect the earliest stage of storage iron deficiency in the organism. For the latter purpose, the determination of erythrocyte ferritin is ineffective.

Blood Donors↗