ON THE NONRECEPTOR EFFECT OF DRUGS AND BIOLOGICALLY ACTIVE
SUBSTANCES
NOSAL, R.

Most of the cationic amphiphilic drugs (CAD) exert their
pharmacological effect through specific receptors which are of
protein origin. These interactions result from a sufficiently
tight and time dependent binding of CAD to the cell surface
transmitting chemical signals into biological effects. For such
events each cell is equipped with a wide variety of second
messengers. Yet the chemical structure of CAD and biophysical
composition of biological membranes enable interactions with
corresponding structures without primarily activating the
receptor. As a rule such interactions bring about a response
characterised as side effect of the individual drug, which might
not be equal to the adverse reaction. Nevertheless, these
interactions may result also in adverse and toxic responses to
the drugs administered.
The nonreceptor interactions between CAD, cells, tissues, organs
and the whole organism depend on the physico-chemical nature of
these drugs and their ability to enter and pass through the
plasma membrane on the side, and on the biological properties of
membrane phospholipids and their integral components, on the
other.
The structure, synthesis, turnover and metabolism of membrane
phospholipids play an important role in these processes. Along
with A2 and C phospholipases, membrane phospholipids are also
donators of the most important second messengers participating
in the control of cell functions, such as signal transmission,
contraction and relaxation of muscles, cell aggregation,
secretion, phagocytosis.
CAD are capable to initiate a biological response bypassing
specific receptors, interfering thus with the functional
structure of membrane phospholipids. This effect is
time-dependent and dose-dependent and besides the above
mentioned changes in cell functions, CAD can initiate induction
of phospholipidoses and nonspecific toxic effects. Further
detailed experimental and clinical studies are required to
provide full understanding of the interactions between CAD and
changes induced in the lipid, protein and carbohydrate cell
structures of individual cells and tissues. (Fig. 10, Ref. 140.)
Key words: cationic amphiphilic drugs; phospholipidoses; side
and adverse drug reactions; phospholipases; blood platelets;
mast cells.
Bratisl Lek Listy 1995; 96:
Address for reprints: MUDR. R. Nosal, DrSc., UEF SAV, Dubravska
2, 842 16 Bratislava, Slovakia.


FREE OXYGEN RADICALS. RELATIONSHIPS TO ATHEROSCLEROSIS AND
DIABETES MELLITUS
FABRYOVA, L., CAGAN, S.
Recent research suggests that reactive oxygen species (including
free radicals) may be involved in the initiation and development
of vascular complications in diabetics. Free radicals meet many
of the criteria required for a role in the pathogenesis of
diabetic vascular disease: they are present in tissues affected
by the diabetic process, they have a direct toxic effect on
tissues, under certain condition glucose molecules can induce
free radicals production. Diabetes represents a state of
increased oxidative stress which is based on evidence of
increased peroxidation, glycoxidation and reduced antioxidant
reserve. Glycative stress can be modified by reducing glycemia,
maintaining good diabetic control, and identifying the patients
in whom diabetes or impaired glucose tolerance has not been
diagnosed. Strategies for reducing the oxidative stress may
include the supplementation of antioxidant micronutrients
(vitamins E and C, beta-carotene). At present the most
appropriate dose, form, method and site of administration of
antioxidants are not known. One interesting therapeutic approach
for the future will be to make apo-B particles more resistant to
oxidative modification or to reduce the prooxidant activity in
general. (Tab. 3, Fig. 5, Ref. 14.)
Key words: free oxygen radicals; atherosclerosis; diabetes
mellitus; antioxidants.
Bratisl Lek Listy 1995; 96:
Address for reprints: MUDr. L. Fabryova, NsP Stare Mesto,
Bezrucova 5, 815 26 Bratislava, Slovakia.


CLINICAL  POSSIBILITY  OF   UTILIZATION  OF  LATE  VENTRICULAR
POTENTIALS
DUBRAVA, M.
The risk of ventricular arrhythmias may recently be analyzed by
late ventricular potentials (LVP). The presented papaer reviews
the pathophysiology of LVP. The author describes some
methodological and technical problems of LVP registration and
examination in clinical practise. The main aim of the paper is to
bring some information on clinical usefullness of LVP. The
situations, when the examination of LVP is accepted diagnostic
method are presented. The author concludes, that examination of
LVP is highly informative, non-invasive, economically acceptable
and available from clinical practical point of view. It is
helpfull for stratification of cardiological patients who need
more intensive diagnostics and therapy. (Ref. 95.).
Key words: late ventricular potencials; ventricular arrhzthmias;
sudden death.
Bratisl. lek. Listy, 96, 1995, c. 1, s.
Address for reprints: MUDr. M. Dubrava, CSc., LFUK, Dumbierska
3, 831 01 Bratislava, Slovakia.


ENDOSCOPIC ULTRASONOGRAPHY IN THE GASTROINTESTINAL TRACT
HROMEC, J.
Endoscopic ultrasonography is a combination of endoscopy and
ultrasonography. This method facilitates an accurate evaluation
of singular layers of the gut-walls and adjacent structures.
Great gain is represented by the possibility to analyze submucosal tumors,
to diagnoze vascular anomalies and especially the staging
of both gastrointestinal malignancies and tumors in the
pancreato-biliary area.
The method is also suitable for the monitoring of treatment
of these malignancies (chemotherapy, radiotherapy and laser
therapy) as well as for an early diagnosis of tumor recurrences. The
paper enumerates the possibilities, limits, some
differential-diagnostic problems, complications, as well as
perspectives of this moder method. (Tab. 4, Fig. 7, Ref. 17.)
Key words: endoscopic ultrasonography (endosonography, EUS);
malignancies in the gut and pancreato-biliary system; tumor
staging in the gut; submucosal tumors; vascular anomalies in the
gut.
Bratisl Lek Listy 1995; 96:
Address for reprints: MUDr. J. Hromec, CSc., NsP, Bezrucova 5,
815 26 Bratislava, Slovakia.


CARDIOLOGIC MANAGEMENT IN PATIENTS WITH REGULAR DIALYSIS
TREATMENT
GONSORCIK, J., PALKO, S., MYDLIK, M.
Cardiovascular complications are the main cause of mortality in
patients with chronic renal failure. Hypertension and lipid
abnormalities which often lead to left ventricular hypertrophy
and accelerated atherosclerosis as well as coronary artery
disease are a common cause of death. On the other hand uremia
often causes pericarditis and thereby may lead to cardiac
tamponade and constrictive pericarditis. Renal failure can also
cause secondary hyperparathyroidism, amyloidosis, hemosiderosis
and oxalosis which can produce visceral infiltrations and lead to
a variety of disturbances of cardiovascular functions.
Life-threatening arrhythmias are one of the major cardiovascular
complications during maintenance dialysis as their occurance
might result in sudden death. The aim of cardiologic management
which includes the complex of preventive and therapeutic measures
is to reduce the morbidity and mortality and to improve the
quality of life. (Fig. 2, Tab. 3, Ref. 20.)
Key words: cardiovascular complications; chronic renal failure;
diagnostic and treatment.
Bratisl Lek Listy 1995; 96:
IV. interna klinika Fakultnej nemocnice L. Pasteura v Kosiciach
Address for reprints: MUDr. J. Gonsorcik, CSc., FN L. Pasteura,
Rastislavova 43, 041 90 Kosice, Slovakia.
Rastislavova 43, 041 90 Kosice, Slovakia.