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Biomedical subjects

M Sovak

Publications and source records attributed to M Sovak.

At least 37 records · Page 2Linked to original sources
PubMed1980

Current investigations in headache.

The responses of supraorbital (SA), superficial temporal (TA), and digital (F) arterial beds and heart rate were studied in 5 normal subjects and 10 migraineurs when hand temperature was increased by volition and/or by heat. In normal subjects, volitional digital arterial dilation coincided with vasoconstriction in SA and TA. In migraineurs, the response varied. Bradycardia resulted in most subjects except in unimproved migraineurs. Heat-induced hand vasodilation led to dilation in SA and TA and to tachycardia. In the 8 migraineurs who improved clinically, the finger temperature feedback training apparently did not result in conditioning of a single autonomic response (i.e. digital vasocilation), but in a general decrease of the sympathetic tonic outflow. Improvement in migraine could also be correlated with improvement in psychological tests, with MMPI scores indicative of neurosis, significantly improving in those patients who learned and practiced the BF technique. A pilot study aimed at detection of serum complement alterations in migraine does not suggest a diminished level of the inhibitor of the first component and further inquiry into the possible serum complement abnormalities in migraineurs is in process. The possible relationships between the vasomotor changes in migraine, the reduction in sympathetic tonic outflow evoked by biofeedback, and their psycho-physiological significance have been discussed. An integrated, interpretative fusion of these data is proposed. A new conditioned vasomotor reflex, which we have termed the relaxation reflex, has been described. It should be explored whether BF has more wide applications in the treatment of other "psychosomatic" disorders characterized by vasomotor abnormalities and increased sympathetic tone.

Adult↗
PubMed1979

Conditioned adaptation-relaxation reflex in migraine therapy.

A new conditioned reflex, the adaptation-relaxation reflex, characterized by dilation of the peripheral blood vessels of the hand and arm, is associated with reduced blood flow in the area of the supraorbital and superficial temporal arteries. This reflex, learned through biofeedback training, is a central requirement for successful autonomic conditioning for migraine. In migraine patients whose conditions improve clinically, the finger-temperature feedback training is not associated with the conditioning of a single autonomic response, ie, digital vasodilation, but is associated with a general decrease of sympathetic tonic outflow.

Adult↗
PubMed1979

Differential accumulation of radiopaque contrast material in acute myocardial infarction.

The differential accumulation of radiographic contrast materials in ischemically damaged and normal myocardium was assessed with direct measurement (fluorescent excitation analysis) of the iodine content of tissue samples from dogs with 48 hour old myocardial infarctions. Tissue samples were obtained 10, 30, 60 and 180 minutes after the intravenous administration of 2 ml/kg body weight of diatrizoate meglumine and sodium (Renografin-76). At all time intervals, the iodine concentration of infarcted tissue was at least threefold greater than that of normal myocardium. At 180 minutes the ratio between iodine concentration in infarcted myocardium and that in normal myocardium was 8.5 and between that in infarcted myocardium and that in blood was 2.6. The iodine concentration in the liver was similar to or greater than that in the infarcted area at time intervals after 10 minutes. These results suggest that the intravenous administration of contrast material may facilitate the identification of acutely infarcted myocardium with computerized X-ray transmission tomography.

Animals↗
PubMed1977

Steroids: theoretical and experimental basis for utilization in prevention of contrast media reactions.

In vitro and in vivo studies were done to examine the effects of methylprednisolone on the adverse reactions induced by contrast media. At very high concentrations, the steroid potentiated the complement-activating effect produced in vitro by iodipamide, but inhibited the immune and nonimmune mechanisms of hemolysis. Rabbits pretreated for 3 days with intramuscular methylprednisolone (at high or low dosages) were significantly protected against an LD47 challenging dose of iodipamide. Those treated once with a low intravenous dose immediately prior to iodipamide challenge were protected to a lesser degree. Rabbits treated once with a very high intravenous dose of steroid evidenced no protection. A hyper-responsive dog was consistently protected against adverse reactions to injected sodium iothalamate by a 3-day steroid pretreatment.

Animals↗
PubMed1976

Synthesis of a potential water-soluble radiographic contrast medium, 2, 4, 6-triiodo-3-acetamido-5-N-methylcarboxamidophenyl beta-D-glucopyranoside.

Starting from 3,5-dinitrobenzoic acid, the infinitely water-soluble compound, 2, 4, 6-triiodo-3-acetamido-5-N-Methylcarboxamidophenyl Beta-D-glucopyranoside (9), was synthesized in nine steps. Glucoside 9, the first example of potentially a new class of water-soluble x-ray contrast media, is rapidly excreted from dog's plasma into the urine, unchanged. It has low intravenous toxicity in mice (LD50 = 24.5 g/kg). Thin-layer chromatography of aqueous solutions of 9 revealed first appearance of aglycon 7 after 1 week at room temperature.

Animals↗
PubMed1976

Studies in the design of x-ray contrast agents. Synthesis, hydrophobicity, and solubility of some iodoresorcyl bis(beta-glucosides).

Two diiodo- and two triiodoresorcyl bis(beta-glucosides) were prepared and their hydrophobicity (log P octano) and water solubility were compared to a triiodophenyl beta-glucoside and several experimental nonionic, water-soluble, x-ray contrast agents. The data indicate steric overlap of the halogen substituents by the bulky hydrophilic O-beta-glucosyl substituents; high water solubility is attained only at observed log P octanol approximately 1.5 or lower. Of the new compounds, only 2,4,-6-triiodo-5-N-methylcarboxamidorescorcy bis(beta-glucoside) (6) was highly water soluble. At the physiological pHin dog's plasmia in vitro, compound 6 rapidly hydrolyzed. Poorly water-soluble but more stable compounds of this series were not appreciably absorbed from dog's duodenum.

Animals↗
PubMed1976

Development of contrast media idiosyncrasy in the dog.

A laboratory dog exhibited an altered response to injections of sodium iothalamate. This idiosyncratic response may have been predicated on an earlier series of iothalamate injections. The overt manifestations of the reactions in this dog were vomiting, hypotension, and hyperreflexia. Significant changes in several electrolyte components and serum complement levels were noted when the dog reacted to the contrast material.

Animals↗
PubMed1976

Perfluoro carbon bromides as contrast media in radiography of the central nervous system. A preliminary experimental report.

A preliminary investigation of the properties of perfluorooctyl bromide in the subarachnoid space revealed this compound to have suitable attenuation capacity and advantageous physical and biologic properties for demonstration of the brain and spinal cord. No acute or chronic neurotoxicity was encountered. Microscopy demonstrated evidence of chronic inflammatory changes subsequent to long term exposure to the compound. It was concluded that the medium was superior to iodophendylate in several respects and that it may provide an alternative to water-soluble contrast media. Perfluorohexyl bromide proved unsuitable for neuroradiologic use because of formation of excessive amounts of non-absorbable gas, leading to high subarachnoid pressure and severe neurologic deficits.

Animals↗
PubMed1976

[On the mechanism of action of acupuncture analgesia (author's transl)].

The correlation between the effects of acupuncture (A) and hypnosuggestion (H) on subjective pain perception was studied in normal volunteers using somatosensory evoked potentials technique. Both methods influenced identically the subjective pain perception and affected the evoked cortical responses similarly. In those subjects in whom analgesia was achieved, location of the A needles proved unimportant and the suppression of the cortical response elicited by A or H was identical. This could be explained by cortically induced inhibitory activity in descending control systems for both methods. A. analgesia thus appears to be a suggestive modality which depends on individual susceptibility. A specific cultural background also seems to be of importance.

Acupuncture Therapy↗
PubMed1975

Preliminary evaluation of di-iodo-triglucosyl benzene. An approach to the design of nonionic water-soluble radiographic contrast media.

A new compound, di-iodo-triglucosyl benzene (DTB), was synthesized and tested for contrast medium potential. It is stable and soluble in water, with a molecular weight of 864 and a viscosity of 33.3 cps at 40degrees C for a 66.6% w/v solution. It is rapidly excreted unchanged by the kidneys. Its estimated LD50 in mice at an intravenous injection rate of 330 mg l/min is 34.0 g/kg. It is highly hydrophilic and not epileptogenic, but its low iodine content (29.4%) makes it unfavorable for clinical use.

Animals↗