Urticaria pigmentosa in identical male twins.
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Adolescent↗
Biomedical subjects
D Dobrota
Publications and source records attributed to D Dobrota.
[Study of malignant melanoma using 1H-nuclear magnetic resonance spectroscopy].
1H-nuclear magnetic resonance spectroscopy was used to study malignant melanoma extract. The aim of this work was to study low molecular weight metabolites soluble in water, which can be helpful for a more detailed understanding of tumor metabolism with a view to using this knowledge for diagnosis. The authors found in a well distinguished spectrum the presence of numerous low molecular weight metabolites such as glutamate, glutamine, choline, inositol, creatine, phosphocreatine, phosphocholine, glucose, acetate, alanine, lactate. It is necessary to correlate these in-vitro findings with a study of the above mentioned metabolites in-vivo. Malignant melanoma is appropriate for this investigative and diagnostic technique because of its superficial localization. (Fig. 1, Ref. 18.)
Humans↗
[Morphologic study of mastocytes from skin biopsies in patients with non-systemic and systemic mastocytosis].
The authors describe morphologic changes in mastocytes in the picture of transmission electron microscopy (TEM) and skin changes in patients with urticaria pigmentosa (7 causes) and systemic mastocytosis (2 causes). The presented study analyzes the changes in the cellular membrane and cytoplasmic processes, intracytoplasmic membrane structures, mitochondria, granules, and nuclei of mastocytes in patients with systemic mastocytosis. The authors evaluate these cells as being atypical, respectively immature. The study discusses the malignization of these states. (Tab. 2, Fig. 8, Ref. 16.)
Biopsy↗
[Interaction of cholesterol and sphingomyelins in membranes of the sarcotubular system after denervation].
We investigated the content of cholesterol and phospholipids in the sarcotubular membranes from the rabbit fast-twitch muscle in various time intervals after the section of sciatic nerve. Along with the unchanged content of total phospholipids we found an increase of cholesterol in all investigated intervals. Significant elevation of cholesterol by about 33.8% following 14 days of denervation is associated with a three-times higher level of sphingomyelins. The elevated level of sphingomyelins persists after 28 days and the molar ratio cholesterol/phospholipids is 2.6 times higher in comparison with the control group. Investigation of cholesterol synthesis on muscle slices from the precursor 14C-mevalonic acid as well as of the activity of HMG-CoA reductase have shown that the cholesterol increase following denervation is not in correlation with its synthesis de novo. Similarly it has been shown that an increase of membrane cholesterol is not linked with the change of membrane fluidity (Tab. 3, Fig. 3, Ref. 30.)
Animals↗
[The role of platelet activating factor in the pathogenesis of asthma].
The work reviews knowledge about the function of PAF, the presupposed mediator of asthma. The PAF mediator evokes contraction of smooth muscles of respiratory passages, too in vivo as in vitro, by means of an indirect mechanism involving activated platelets which function as intermediaries. The constrictor released due to this process can be represented by histamine or a product of arachidonic acid. Mucous secretion is according to current knowledge stimulated by PAF. The PAF mediator appears to be a considerable chemotactic factor for eosinophils which by their cytotoxic effects on respiratory epithelium support the origin and development of bronchial hyperresponsiveness. PAF has an eminent effect on the growth of microvascular permeability. Antagonists of PAF inhibit some mentioned PAF effects. Their possible therapeutic utilization, excluding ketotiphen, are currently subjected to research. (Fig. 2, Ref. 17.).
Asthma↗
[Carnosine and anserine in working muscles--study using proton NMR spectroscopy].
NMR spectroscopy was used to study carnosine and anserine metabolism in rat tissues under intensive muscle loading. Muscle loading was accompanied by the dipeptide (predominantly anserine) accumulation in muscle tissues. Preliminary per os administration of carnosine (250 mg/kg of body mass) did not increase the dipeptide content in muscle tissues but diminished the lactate content in rat muscles under intensive muscle loading.
Animals↗
Effects of denervation on the contents of cholesterol and membrane systems involved in muscle contraction in rabbit fast-twitch sarcotubular system.
Denervated fast-twitch rabbit muscles were progressively losing their fresh weight and the yield of sarcotubular protein was increasing. The activity of Ca(2+)-ATPase was affected but very slightly, the basal Mg(2+)-ATPase and the Mg(2+)-ATPase/Ca(2+)-ATPase ratio however increased together with a simultaneous depression of the membrane-bound acetylcholinesterase activity. We did not observe any differences in density properties of sarcotubular fractions between control and denervated muscle. However, a relative enrichment in SM and H fraction could be seen after denervation with small changes in the content of the Ca(2+)-pump protein, increased levels of calsequestrin and cholesterol, mostly in the heavy and the SM fraction. After denervation the binding sites for 3H-PN-200-110 did not show any changes in receptor affinity, but the number of putative Ca(2+)-channels increased twice along with a depression of 3H-ouabain binding sites. We suggest that the denervation of fast-twitch muscle leads to the hypertrophy of the junctional sarcoplasmic reticulum and the T-system. Changes in the cholesterol content, in the number of putative Ca(2+)-channels and in Na+, K(+)-ATPase can affect the muscle contraction.
Acetylcholinesterase↗
Phospholipids in demyelinating diseases.
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Animals↗
Transport mechanism of L-[14C]glutamate in cortical slices and synaptosomes of rabbits exposed to brain ischemia and reperfusion.
Changes in the functioning of the glutamatergic system in rabbit brain were studied after partial brain ischemia and reperfusion. In vitro studies were conducted relating to the release of L-[14C]glutamate from cortical brain slices, L-[14C]glutamate uptake in synaptosomes, and 45Ca uptake in synaptosomes. It was found that basal release of L-[14C]glutamate from rabbit brain cortical slices after 30 min of partial ischemia and 1 d of reperfusion was essentially without change compared to the control values. After 3 d of reperfusion, there was an increase in basal release of L-[14C]glutamate from rabbit brain cortical slices. K+ stimulated release of L-[14C]glutamate in normal Krebs-Ringer medium was essentially the same in the control group and in the experimental group after 30 min of ischemia. The K+ stimulated release of L-[14C]glutamate independent of calcium was increased to 145% after 30 min of ischemia and 1 d of reperfusion. The decreased Km value at the glutamate transporter may have contributed to this difference. Kinetic parameters of the L-[14C]glutamate uptake (Km and Vmax) in synaptosomes from rabbit brain were significantly lower after 30 min of ischemia. The authors discovered that during the reperfusion period, Vmax was almost the same as in the control group. The activity of the Na+/Ca2+ exchanger in synaptosomes of rat brain was about 70% of the control values after 30 min of ischemia and 72 h of reperfusion. According to our results, increased L-[14C]glutamate release after 30 min of ischemia appears to be the result of higher intracellular calcium concentration and possibly also of a higher uptake of glutamate.
Animals↗
Relative resistance of rabbits to MPTP neurotoxicity.
The neurotoxic actions of MPTP and its 4-(O-tolyl) analog (2'-Me-MPTP) on two breeds of rabbits were investigated. MPTP, but not 2'-Me-MPTP, causes a reduction (about 40%) in striatal dopamine content in rabbits of the "little silver-black" breed. The dopamine content of striata of "chinchilla" rabbits was not affected by either agent.
1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗