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Biomedical subjects

J Hampl

Publications and source records attributed to J Hampl.

At least 37 records · Page 2Linked to original sources
PubMed1994

[The effect of sodium huminate on cadmium deposition in the organs of chickens].

In the chickens with an experimental load of cadmium chloride (CdCl2 x 2.5 H2O) at a rate of 0.3 mg per bird and day the effect was investigated of various forms of sodium humate administration in free and/or liposomal form as exerted on cadmium concentrations in liver, kidneys and muscle. The values of the field below the curve (AUC) showing average cadmium concentrations in the investigated tissues of chickens (liver, kidneys, muscle) in the given time interval of 1-14 days were higher in all cases in the tissues of chickens which received cadmium, that means in the groups K2, P1, P2, P3 and P4 in comparison with the negative control (K1). Statistical significance of differences was demonstrated in liver and kidneys. No statistically significant changes were observed in the muscle. Simultaneous administration of cadmium and HuNa (P1), and also other methods of HuNa administration (P2, P3, P4) reduced cadmium concentrations in liver, kidneys and muscle statistically significantly only in P1 group in liver and kidneys. Cadmium concentrations on days 1, 3, 8 and 14 after termination of experimental treatments were lowest in the liver of the 1st control group (negative control), which received HuNa only (Tab. I). Five-day administration of 0.3 mg cadmium (positive control) influenced its values statistically highly significantly in the liver of all experimental groups in all the investigated time intervals (Tab. I). The first experimental group, which received cadmium simultaneously with HuNa had the statistically significantly lower values on days 3, 8 and 14 in comparison with the positive control. Simultaneous administration of cadmium and HuNa reduces cadmium availability and so its absorption and deposition in liver are lower. Cadmium concentrations on days 1, 3, 8 and 14 after termination of experimental treatments were lowest in the kidneys of chickens of the 1st control group (negative control), which received HuNa only (Tab. II). Five-day cadmium administration (positive control) influenced its values in the kidneys of all experimental groups highly statistically significantly in all the investigated time intervals (Tab. II). The first experimental group which received cadmium simultaneously with HuNa had the statistically significantly lower values on days 3, 8 and 14 in comparison with the positive control. Simultaneous administration of cadmium and HuNa reduced cadmium availability and so its absorption and deposition in liver are lower. Cadmium concentrations in the muscle on days 1, 3, 8 and 14 after termination of experimental treatments were lowest in the 1st control group (negative control), which received HuNa only (Tab. III).(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1993

[Isolation of toxic peptides from Amanita phalloides and their analysis using high-performance liquid chromatography].

The objective of the work is isolation of toxic peptides from Amanita phalloides--amatoxins (alfa-, beta-, gamma-amanitin) and phallotoxins (phalloidin, phallacidin, phallisin, phallisacin) by liquid chromatography on Sephadex LH-20 according to Yocum modification. Seven main toxins were isolated in centigram amounts. The purity of the toxins isolated was verified by the characteristics of their absorbance spectra, by thin layer chromatography (TLC) and high-performance liquid chromatography on reversed phase (RP-HPLC). The fraction of acid phallotoxins which appears homogenous in TLC and Sephadex LH-20 was separated into 5 substances (four of which are phallotoxins) by preparative RP-HPLC technique. The toxins isolated are sufficiently pure to be used as standards in HPLC.

Amanita↗
PubMed1993

[Does a hypertensive reaction to dynamic exercise imply an increased risk of developing essential hypertension?].

Early diagnosis of essential hypertension, preferably in the pre-hypertensive stage, is very important for the prognosis of affected subjects. Based on sporadic information in the literature it seems that people who are normotensive at rest but have an exaggerated hypertensive reaction to exercise have a greater risk of developing essential hypertension in future. The authors selected from protocols of ECG exercise tests a group of subjects with normal blood levels at rest but an exaggerated hypertensive reaction to a dynamic exercise. The control group was formed by people with a normal pressure reaction to a exercise the control group was matched as regards age, sex and basic anthropometric parameters. After a mean period of 7.8 years (range 5-10 years) it was revealed that while in the control group hypertension was manifested in 10%, in the group with an exaggerated hypertensive reaction to an exercise it was manifested in 33.3%. The mean original blood pressure readings at rest were significantly higher in people with a normal blood pressure reaction to an exercise and this difference persisted also at the end of the investigation. An exaggerated hypertensive reaction to a dynamic exercise is one of the prognostic factors for the development of essential hypertension and should be a reason for follow-up.

Adult↗
PubMed1992

In vitro processing of insulin for recognition by murine T cells results in the generation of A chains with free CysSH.

Studies on the processing of insulin as an Ag for the presentation to MHC class II-restricted T cells revealed that the amino acid residues 1-14 of the insulin A chain are recognized by insulin-specific T cells. An A1-14 peptide containing three cys-residues that were protected by S-sulfonate groups still needed processing by APC for efficient presentation similar to native insulin. We suspected that reductive deblocking or opening of disulfide bonds that generates CysSH-residues may be an essential processing step for these Ag. Due to the instability of SH-groups it was not possible to test A chain peptides with free SH-groups in the usual way for processing-independent presentation by fixed APC. However, under acidic conditions (pH 5) during APC pulsing with the Ag we could demonstrate that the freshly reduced A1-14 fragment as well as reduced insulin are able to bind to Ia Ag and to stimulate appropriate T cells without further processing. Various substitutions of cys-residues by Ser within this peptide revealed that only CysA7 is critical for Ia binding and/or T cell recognition. In intact insulin, this residue links the A chain containing the T cell epitope to the B chain. Therefore, we propose that insulin processing is not dependent on proteolysis or on the generation of a conformational determinant but on the separation of A and B chains resulting in A chains whose cys-residues are converted into CysSH.

Animals↗
PubMed1992

Memory disturbances following anterior communicating artery rupture.

Thirty patients with lesions due to the rupture and repair of an aneurysm of the anterior communicating artery were compared neuropsychologically with 27 patients with ruptures but no lesions and 30 normal control subjects. Patients with combined lesions in the basal forebrain and striatum (n = 5), or basal forebrain, striatum, and ventral frontal cortex (n = 7), had severe memory deficits, whereas patients with lesions in the basal forebrain (n = 7) or the striatum (n = 5) alone showed virtually no deficits. Patients with lesions of the basal forebrain and ventral frontal cortex together (n = 6) showed mild memory deficits. In contrast to the memory effects, emotional changes were most pronounced in patients with striate lesions alone. Basal forebrain or ventral frontal lesions ameliorated rather than aggravated the emotional effects of striate lesions. It is suggested that the basal forebrain and the striatum form links of different pathways related to mnemonic information processing. Both systems may be able to compensate for a dysfunction of the other, but lesions of both systems together may lead to strong and unrecoverable memory deficits.

Affect↗
PubMed1991

Commercial external ventricular drainage sets: unsolved safety and handling problems.

Twelve commercially available sets for drainage of cerebrospinal fluid were tested for handling, design, features for fixation of the ventricular catheter, reliability of the anti-reflux valve, obstruction, efficiency of the air ventilation filter caps, accuracy of flow measurement and adjustment of flow, quality of material, adjustment, and cost. All systems showed considerable deficiencies in their reliability and handling. None of them can be recommended without certain restrictions and they should all be revised.

Brain Diseases↗
PubMed1991

[Esophageal perforation and pneumothorax. Complications due to placement of a stomach tube].

Perforation of the oesophagus, as well as a pneumothorax are described as complications of the use of a nasogastric feeding tube. Clinical tests to determine correct placement are noted to be unreliable and the importance of radiological control, especially in the unconscious patient, ist stressed. The suspected diagnosis of oesophageal perforation should be verified without delay to immediately initiate conservative or surgical treatment.

Adult↗
PubMed1990

Processing without proteolytic cleavage is required for recognition of insulin by T cells.

Beef insulin as well as a chymotryptic A-chain fragment [BI-A1-14(SSO3-)3] need uptake by antigen-presenting cells (APC) for efficient presentation in combination with major histocompatibility complex class II molecules to insulin-specific T cells. This could be shown by the inability of aldehyde-fixed APC to present these antigens to T cells. Furthermore, presentation of the insulin fragment as well as presentation of ovalbumin (OVA) was inhibited by treatment of APC with chloroquine, cerulenin or tunicamycin. This was not the case for a processing-independent OVA peptide. Treatment of APC during antigen pulsing with various protease inhibitors, active on all classes of proteases, did not block presentation of insulin although some of these reagents did interfere with the presentation of OVA. Several inhibitors especially of serine or thiol proteases rather enhanced the presentation of insulin. This indicates that intracellular proteolytic cleavage of insulin does not seem to be required for generation of the antigenic determinant but, if it occurs, rather destroys the antigenic peptide. Insulin and its A-chain fragment may, therefore, represent a model for a processing-dependent antigen not requiring proteolytic cleavage but other modifications.

Animals↗
PubMed1990

Nimodipine: evidence for clinically significant gastrointestinal side-effects.

Nimodipine, now widely used for treatment and prevention of cerebrovascular spasm, is regarded as a safe drug. Despite a preferential action on cerebral vessels, there is clinical and experimental evidence of effects on systemic vascular and intestinal smooth muscle cells. Gastro-intestinal side-effects, however, have not been reported in clinical studies dealing with treatment of vasospasm following subarachnoid haemorrhage. We report on a patient with subarachnoid haemorrhage who developed an acute life-threatening pseudo-obstruction of the colon, a variant of adynamic ileus, while being treated with intravenous nimodipine. The relationship between this complication and calcium antagonist therapy is discussed and therapeutic strategies are presented. We conclude that neurosurgeons and neurologists should be aware of calcium antagonist--related ileus in patients treated with nimodipine.

Colonic Diseases↗
PubMed1990

Enzyme-linked immunosorbent assay of antibodies to rabbit haemorrhagic disease virus and determination of its major structural proteins.

An ELISA was developed for the determination of antibodies to rabbit haemorrhagic disease virus (RHDV) in whole blood and blood serum of rabbits. Naturally acquired antibodies were detected in 19.4% of blood samples collected from 1461 rabbits in 43 farms apparently free of the disease, 19.7% samples were doubtful and 60.9% of the rabbits were free of antibodies to RHDV. Their presence has a considerable effect on the resistance of rabbits to infection with RHDV. Antibodies were also found in rabbit blood serum samples collected up to 12 years before the first outbreaks of RHD were reported. Up to 14 viral protein antigens were determined by PAGE and Western blot analysis, of which three with Mr values of 61K, 38K and 52K were major proteins, the 61K being dominant. Our hyperimmune sera, a Chinese reference serum and sera with positive antibody titres, including those collected several years before the first outbreaks of RHD, reacted identically with these antigens in the Western blot analysis. The data obtained suggest that naturally acquired antibodies are a product of a specific response to prior infection with an avirulent strain of the virus.

Animals↗
PubMed1990

[Maltose-dextran--a new combination solution for the induction of diuresis in man].

40 healthy men received an infusion solution of low molecular dextran with either 0%, 5%, 10% or 20% Maltose over a 60 min period. The combination of LMWD with 10% maltose solution showed a significant increase of urine excretion from 132 ml/h to 315 ml/h at the end of the infusion. The overall excretion rate in 3 h was 683 ml, 185 ml more than infused. The increase in urine excretion from 53.0 ml/h to 173.5 ml/h after the application of 5% maltose/dextran 40 solution was only due to a water diuresis. The maltose concentration was not high enough to induce a visible osmotic diuresis. The application of 20% maltose/dextran 40 solution showed a clear osmotic effect. Nevertheless, there was no significant increase in the urinary excretion rate compared to the LMWD solution without any maltose. The high oncotic and osmotic pressure of this combination activated mechanisms, which were opposed to the induced osmotic diuresis.

Adolescent↗
PubMed1990

[Cesium transfer in short food chains].

An investigation of 25,000 samples of foodstuffs and feedstuffs in Czechoslovakia, contaminated by fall-out cesium after the accident in the Chernobyl nuclear power plant, performed from May 5, 1986 to March 31, 1988, revealed that both the values of cesium transfer-factors in food--animal tissues--milk transitions and the values of biological half-life of cesium are functions of internal and external conditions of contamination. Organism individuality as the main internal condition causes the variance of about +/- 50% of the mean value of the respective transfer-factor. Through the external conditions, mainly the environmental contamination level, type of ingested food and time of ingestion, the mean values of transfer-factors are influenced up to 500%, e.g. to the value of 0.5. But this value converges with growing up contamination of food and environment to the limit of 0.3. The first two to three biological half-lives after the last ingestion of contaminated food are up to ten-times shorter than those at stabilized state.

Accidents↗
PubMed1989

[Safe placement of atrial shunt catheters using intracardiac ECG. Initial experiences with a new ECG adapter system in 33 patients].

In 1960 Robinson inaugurated the method of placing atrial shunt catheters with the help of intracardiac ECG monitoring. Vulnerability to artifacts and problems with electrical safety (which have since been solved) led to its disuse. A newly developed ECG adapter proved free from artifacts and was practicable in 33 patients. 31 shunts were correctly placed without requiring time-consuming radiography. 2 extracardiac false positions were clearly identifiable by means of true negative results, which after correction showed a typical atrial ECG. The ECG method is compared with 9 other positioning methods. It seems to be superior to the conventional chest x-ray and equal to fluoroscopy. However, the method is not on a par with sophisticated measuring techniques such as intracardiac pressure monitoring or intravasal sonography.

Adolescent↗
PubMed1988

Processing requirements for the recognition of insulin fragments by murine T cells.

In this study we investigated aspects of antigen processing using insulin and insulin A chain-derived fragments as model antigens in Ab alpha Ak beta-restricted T-cell stimulation. Similarly to other proteins, the immunodominant region of insulin recognized by these T cells is limited in size. It is located on the insulin A chain and encompasses a portion of the molecule that is represented faithfully by peptide A1-14(SSO3-)3. Efficient presentation of intact insulin and its entire A chain is dependent on uptake and processing by APC. Whereas peptides stemming from various globular proteins are known to be presented to T cells by APC without requiring processing, this is not the case with A-chain fragment A1-14 (SSO3-)3. This observation suggested that, in addition to proteolytic degradation, other mechanisms might play a role in the processing of these antigens. Three cys-residues are located in close proximity to those amino acid residues of the insulin A chain that are inferred to participate in the specific interaction with MHC class II molecules and the TcR. In A-chain derivatives that are stimulatory for the T cells or in intact insulin these cys residues are engaged in disulfide bonds or are S-sulfonated. Both linkages can be reversibly modified by reaction with thiols. Functional data indicate that from intact insulin and from structurally distinct A-chain derivatives a closely similar or identical peptide is formed and bound to class II molecules for recognition by the T cells. The question arises as to whether, in this processed peptide, the cys residues are present in reduced form, engaged in disulfide bonds, or are modified in some other way. Taken together, these findings suggest that modification of cys residues or isomerization of disulfide bonds may play a role in insulin processing. It can be expected that other proteins carrying cys residues in their immunodominant peptides may show similar processing requirements. The inhibition of N-glycosylation of proteins by tunicamycin in APC blocked the processing and presentation of insulin and OvA whereas, under the same conditions, the presentation of a processing-independent peptide was not affected. Furthermore, an autoreactive T-cell clone was capable of recognizing tunicamycin-treated APC. Since the expression of class II molecules was found to be unaltered as demonstrated by cytofluorometric analysis the deficient N-glycosylation appears to have little influence on class II antigen-mediated T-cell recognition but interferes with uptake of antigen and/or its processing by APC.

Animals↗
PubMed1986

[Spontaneous infection of cell lines with mycoplasmas and their detection using the fluorescence method].

The continual cellular lines of bovine kidneys MDBK and AUBEK and of monkey kidneys VERO were infected spontaneously in the course of long-range cultivation by the mycoplasmas M. arginini and A. laidlawii. The mycoplasmic infection reduced significantly the growth activity of the cells and influenced negatively their morphology. The method of an indirect proof of mycoplasmas by bisbenzimid Hoechst suited well to demonstrate the infection; it had been modified to a simple and rapid test. The starting infection could be demonstrated already at the time when the amount of infected cells in the culture was relatively low.

Bisbenzimidazole↗