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Biomedical subjects

Z Deyl

Publications and source records attributed to Z Deyl.

At least 73 records · Page 4Linked to original sources
PubMed1989

The contribution of discrimination analysis to the diagnostic decision in patients with lung carcinoma.

A set of 620 patients was examined. Out of them, 245 suffered from lung carcinoma of different type and stage, 28 suffered from other malignant tumors, 37 were affected with benign tumors, and 166 were suffering from a nonmalignant respiratory disease (tuberculosis, nonspecific pneumonia, chronic bronchitis, abscesses, cysts, asthma, lung fibrosis, bronchiectasis and sarcoidosis). In addition to these patients, 144 blood donors were examined who represented the control group of healthy individuals. In a blind test another set of 266 persons was examined. By completing the values of selected markers (orosomucoid, prealbumin, glycoprotein electrophoresis, erythrocyte sedimentation, age of the individual, and the number of smoked cigarettes) into the discrimination rule and by calculating the discrimination function, a sensitivity of 80.6% and a specificity of 75.6% were obtained. A comparative cytological examination of the same set revealed lower sensitivity (61.0%) but higher specificity (98.0%). These values were verified in a blind test, as the patients were admitted to the hospital. Sensitivity in lung cancer was found to be 83.9%; in nonmalignant diseases the respective value was 77.1%. This approach can be applied to individuals suspect of cancer, in secondary prevention and in individuals with a high risk of lung cancer.

Adult↗
PubMed1988

Determination of fatty acids as phenacyl esters in rat adipose tissue and blood vessel walls by high-performance liquid chromatography.

Twenty-two biologically relevant (6:0-22:6) saturated, monounsaturated and polyunsaturated fatty acids were separated by reversed-phase high-performance liquid chromatography after derivatization with phenacyl bromide. An optimal resolution of the critical combinations linolenic-myristic, docosahexaenoic-palmitoleic-arachidonic and palmitic-oleic acids and cis and trans isomers of octadecenoic (n9) and octadecadienoic (n9, 12) acids was achieved by continuous gradient elution with methanol-acetonitrile-water. Elution of mixtures of 6:0-22:1 fatty acids was completed within 80 min at a flow-rate of 1 ml/min. By the use of UV detection at 242 nm the detection limits for short- and long-chain fatty acids were found to be about 0.8 and 12 ng per injection, respectively. Linearity was tested up to 100 ng. The method was applied to the determination of fatty acids in rat adipose tissue and blood vessel walls of animals fed hydrogenated fat diets. The results are comparable to those obtained by gas chromatography and surpass the latter for the resolution of oleic and elaidic acids.

Acetophenones↗
PubMed1988

The effect of low protein-high dextrin diet and subsequent food restriction upon life prolongation in Fischer 344 male rats.

Fischer 344 rats fed low protein-high dextrin diet exhibit a higher median (but not 10th percentile) survival as compared to controls. The effect of this diet appears already if the diet is administered between 6 weeks and 6 months of age; after this treatment median survival of experimental animals is increased by 96 days while the 10th percentile is not different from standard diet-fed controls. Further treatment of animals with the same diet has minimum effect as animals that lived on this regimen throughout the whole life exhibited a median lifespan increase by 120 days and increase in the 10th percentile by 41 days. However, if such animals at the age of 6 months are transferred to a restricted (60%) food intake regimen (control diet, not carbohydrate enriched) a further increase in median and 10th percentile lifespan prolongation can be observed reaching +328 and +396 days respectively as compared to controls. The effects of this early feeding (6 weeks to 6 months) with a low protein-high carbohydrate diet available ad libitum and the food restricted regimen (standard diet 60% controls) fed from the age 6 months onwards are additive, the final results being identical to those obtained if the animals were kept on the 60% food restricted intake throughout the whole life. The fact that animals fed the low protein-high carbohydrate diet and those kept on 60% standard diet food restriction had different survival though they were equal in daily (identical) protein intake is emphasized.

Animals↗
PubMed1988

Changes in type V collagen in the kidneys of DOCA-NaCl treated rats.

Type V collagen was extracted and quantitated in the kidneys of unilaterally nephrectomized rats exposed to desoxycorticosteron acetate (DOCA-NaCl) treatment. A highly elevated content of collagen type V was found in these kidneys compared with controls. A higher content of collagen type V was present both in the pepsin digest of the total kidney and in the isolated glomerular basement membranes. It was previously reported that one of the factors involved in the growth of the remaining kidney in unilaterally nephrectomized DOCA-NaCl treated rats is the increase of collagen type IV, the effect being more prominent in rats nephrectomized at a younger age. The present study documents that the increase of type V collagen follows the same pattern.

Animals↗
PubMed1988

Collagen in the aortae of spontaneously hypertensive (SHR) rats.

A biphasic pattern of collagen biosynthesis was found in the aortae of spontaneously hypertensive (SHR) rats; the time course of the rate of biosynthesis is similar to that described in the heart by Sen and Bumpus. In comparison to age-matched controls, collagen biosynthesis is elevated in the SHR rats, diminishes during the first fourteen weeks and rises again at the stage of established hypertension. In the period of established hypertension, the increased rate of collagen biosynthesis was associated with a pronounced rise of the collagen type I to type III ratio. On the other hand, in the pre-hypertensive stage, the proportion of collagen type III clearly exceeds the proportion of collagen type I in SHR rats.

Animals↗
PubMed1987

Collagen and elastin synthesis in the aorta of spontaneously hypertensive rats.

The biosynthesis of collagen and elastin was followed during the development of spontaneous hypertension in rats (SHR) of the Okamoto-Aoki strain. Strain-matched animals of the same age, which did not develop hypertension, served as controls. Both collagen and elastin synthesis (as revealed by specific hydroxyproline activity) was found to exceed control levels in the prehypertensive period, to decrease during the development of hypertension and to increase again in the period of the established hypertensive state. From the two main collagen types present, synthesis of collagen type III exceeded that of type I in the prehypertensive period (at the age of 4 weeks) and this relation was reversed during the period of established hypertension. It is suggested that (a) the vascular connective tissue metabolism in SHR differs from that in strain-matched controls, and (b) the reverse rate of collagen type III to collagen type I synthesis during hypertension development may be considered an adaptive response to the increasing pressure load which may alter the mechanical properties of the vessel wall.

Animals↗
PubMed1987

The mechanism of action of molybdenum and tungsten upon collagen structures in vivo.

The effect of in vivo administration of molybdenum (as sodium molybdate) and tungsten (as sodium tungstate) was investigated in the skin of laboratory rats. It was proved that the amount of both bound molybdenum and tungsten in collagen is relatively small being 0.05 and 0.06 moles per mole respectively. Besides the fraction of firmly bound molybdenum and tungsten a much higher extractable pool of both these metals was found. It was also demonstrated that in vivo shadowing of collagen is caused by the fraction of loosely bound metals. On the other hand pronounced changes were shown in the mechanical properties of connective tissue after molybdate and tungstate administration. Surprisingly, the change in mechanical properties indicated a lower level of cross-linking after the administration of the investigated metals. It is therefore concluded that bitopical binding of molybdenum and tungsten in the collagen structure is unlikely. It also appears that the biological effect of these metals is due to the competition with copper and the interference with the physiological cross-linking reactions based on the partial blockade of lysyloxidase.

Animals↗
PubMed1987

Steric hindrances in protein permeation through the basement membrane studied in acellular kidney.

Acellular kidney preparations were used for studying the steric hindrances in the glomerular basement barrier. In accordance with the reports of other authors our data have provided evidence that, in this model the basement membrane does not suffer from gross ruptures and also preserves its integrity with regard to the proteoglycan moiety. Detergent treatment of the passing protein solution (used for the removal of cellular elements) results in abolishing charge differences. Under such conditions the molar percentage of proteins passing through the GBM barrier is inversely proportional to the logarithm of relative molecular mass. Application of different detergents in preparing the acellular kidney (Triton X-100 and sarcosyl) and in the treatment of individual proteins under study leads to linear relationships of different slopes which is ascribed to the differences in electrostatic repulsive forces introduced by the detergent. The proportion of molecules passing through the GBM barrier increases with increasing protein concentration in the perfusate approaching a limiting value at very high concentrations (0.1 mmol/l). This indicates that the individual protein molecules compete for the free space in basement membrane channels, a conclusion further supported by the fact that permeation of a protein through the barrier can be effectively blocked by increasing the overall protein concentration in the perfusate with another protein species.

Animals↗
PubMed1987

Changes in the blood vessel wall elastin of spontaneously hypertensive (SHR) rats.

It has been demonstrated that both elastin and tropoelastin preparations obtained from aortae of spontaneously hypertensive rats at the stage of established hypertension differ in their amino acid composition from age-matching controls. The differences refer to an increased proportion of polar amino acids, particularly aspartic and glutamic acid (about a two-fold increase compared to the controls) and arginine and tyrosine (1.5 times the control value). On the other hand, this increase is compensated for by a decrease in the valine concentration. Furthermore, direct estimation of the number of val-pro sequence in different elastin preparations indicated a drop from 49.3 to 29.2 per 1,000 residues in normotensive controls and preparations obtained from spontaneously hypertensive rats respectively.

Amino Acids↗
PubMed1986

Profiling of amino acids in body fluids and tissues by means of liquid chromatography.

The needs of urgent diagnoses and the needs emerging from acute forms of diseases have directed progress in amino acid profiling to modern, rapid, automated analyses that can be done at reasonable cost. The first step in this direction was the short programmes of classical ion-exchange chromatography. At the beginning of this review we attempted to survey methods of sample preparation and sample treatment, as these are frequently neglected stages where artefacts or erroneous results may arise. There are basically the following approaches in amino acid profiling by liquid chromatographic techniques. For preliminary screening of a large number of samples in clinical routine planar procedures are the methods of choice, as they allow large numbers of samples to be handled with minimum effort and at very reasonable cost. For more precise profiling, particularly where quantitative data are essential, one can choose between some of the modern procedures for separating underivatized amino acids using modern equipment for cation-exchange chromatography, by making use of a stepped series of lithium citrate buffers with ninhydrin, o-phthalaldehyde or 4-fluoro-7-nitrobenzo-2,1,3-oxadiazole detection. Ninhydrin detection is preferred in those situations where the demands on sensitivity are not high. Where, however, only small amounts of samples are available or high sensitivity is required, one of the latter two methods is preferred. The o-phthalaldehyde procedure is not suitable for the detection of secondary amines and, if these are of interest, then diazole derivatization is to be preferred. At present, however, the ninhydrin and o-phthalaldehyde detection procedures are the most popular. The other choice is to use one of the sophisticated HPLC systems equipped with fluorescence detection and to separate amino acids as derivatives. Here o-phthalaldehyde and 4-fluoro-7-nitrobenzo-2,1,3-oxadiazole derivatives offer the most versatile possibilities. Automation and computerization have penetrated both categories of liquid column separation and are applied to automated sample delivery, automated and computerized gradient formation and quantitation of the data obtained. The tables of metabolic disorders of amino acids and the roles of different amino acids in these disorders should provide preliminary information for clinical chemists.

Amino Acids↗
PubMed1986

Salt and experimental hypertension: the influence of age.

In a series of experiments, age-dependent differences in the development of DOCA-saline hypertension (HPT) were studied in the rat. Immature animals developed--in contrast to the adult ones--a more severe and self-sustaining HPT, associated with a more pronounced retention of fluid and a greater increase of renal collagen which was preceded by a more rapid decrease in renal renin content. It is suggested that changes in intrarenal haemodynamics due to the suppression of renal renin-angiotensin system play a role in the pathogenesis of hypertensive renal lesions which develop more readily in immature animals and are responsible for their more severe HPT. Similarly, monkeys exposed to increased salt intake from earliest stages of postnatal ontogeny are also more prone to develop salt hypertension more rapidly than the adult ones. The increased salt intake before sexual maturity may thus be considered as a risk factor for the development of hypertension also in man.

Administration, Oral↗
PubMed1985

Changes in elastin composition in aorta of spontaneously hypertensive rats (SHR).

Tropoelastin and elastin preparations obtained from aortae of spontaneously hypertensive rats (SHR) show an increased proportion of polar amino acids (aspartic acid, glutamic acid, arginine and tyrosine). The content of these amino acids is 1.43-3.04 times higher in SHR rats than in similar elastin or tropoelastin preparations obtained from normotensive animals. On the other hand elastin and tropoelastin preparations obtained from SHR rats show a lower frequency of the Val-Pro sequence; this was found to be 35.93 per 1000 amino acid residues in SHR rats as compared to 51.04 per 1000 amino acids in the preparations obtained from control animals. Since similar differences were found not only in elastin preparations but also in tropoelastin, contamination of these preparations with an acidic protein seems unlikely. In general the results obtained are similar to those seen in animals kept on a long term high fat diet. It appears feasible to suggest that these differences are caused by a changed proportion of two different elastin type.

Amino Acids↗