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ACTIVATION OF THE NEUROENDOCRINE SYSTEM UNDER STRESS-INDUCED ALTERATIONS OF HOMEOSTASIS
VIGAS, M., JEZOVA, D.
Neuroendocrine response to stress stimuli is aimed to main-tain body
homeostasis. The activation of the neuroendocrine system is accomplished
mainly by two ways: by feedback regulation based on the recognition of
altered metabolic homeostasis by appropriate receptors sending the signal
into the CNS, and by forward regulation involving a direct stimulation
of the neuroendocrine system by a central command coming from an activated
brain regulatory center. With regard to mechanisms of neuroendocrine activation,
the signal specificity and site of its origin are of particular importance.
The significance of the signal inneuroendocrine responses has been evaluated
in three different stress conditions: hypoglycemia, surgical trauma and
dynamic physical exercise. The stimulus inducing neuroendocrine response
during hypoglycemia is the glucopenia. The signal for the activation of
the neuroendocrine response is generated in glucosensitive cells which
are not located in a single brain structure (hypothetical glucostat). The
signal for growth hormone, vasopressin and oxytocin release is produced
in brain structures protected by the blood-brain barrier, that for ACTH
release in regions both protected and unprotected by the barrier, while
the signal for prolactin release is generated in tissues lacking the blood-brain
barrier. The neuroendocrine response during surgical trauma is activated
by a signal formed in the damaged tissue reaching the CNS by neural pathways.
Moreover, cytokins may participate on endocrine stimulation in those surgical
interventions in which a large amount of bacterial endotoxins is released.
During a complicated surgery, e.g. during a bypass, other signals and modifying
factors, such as hypothermia, dilution of blood, hypoperfusion of organs,
rewarming of the body and hormone degradation in the oxygenator are important.
On the other hand, during a short-term dynamic exercise, a forward regulation
by a central signal from the activated CNS motor center comes into play
with the consequent release of catecholamines, growth hormone, etc. In
the control of some other hormones (beta-endorphin, partly ACTH) and especially
during a long term exercise, neural signals from work-ing muscles (feedback)
are also involved. During a static exercise mainly catecholamines triggered
by signals from working muscle cells are activated. The understanding of
the signal and mechanisms of neuroendocrine activation during stress is
indispensable for selective modulation of physiological and patho-logical
responses.
Key words: neuroendocrine regulation, hormones, hypoglycaemia,
surgical stress, physical exercise.
Bratisl Lek Listy 1996; 97: 6371
NEW APPROACHES TO EVALUATION OF THE SYMPATHOADRENAL SYSTEM ACTIVITY IN BASAL AND STRESS CONDITIONS
KVETNANSKY, R.
The sympathoadrenal system (SAS) activity in mammals has usually been
evaluated by measuring plasma and urinary catecholamine (CA) levels. The
aim of this work was to explain theoretically and to demonstrate practically
in own experiments new methods for evaluation of SAS activity. Nowadays
methods are available which estimate not only plasma levels of CA but also
CA release, spillover, reuptake, degradation, and also in vivo CA synthesis
by determination of plasma dihydroxyphenylalanine (DOPA) levels.
In our experiments simultaneous measurements of plasma CA, their precursor
DOPA, the deaminated metabolites dihydroxy-phenylglycol (DHPG) and dihydroxyphenylacetic
acid (DOPAC), and the O-methylated metabolites normetanephrine (NMN), me-thoxyhydroxyphenylglycol
(MHPG) and homovanillic acid (HVA) were performed in humans and rats during
basal and stress conditions. Plasma CA levels are determined by the rate
of CA spillover into the bloodstream and by plasma CA clearance. Immobilization
stress (IMO) markedly increased plasma noradrenaline (NA) levels but NA
spillover was less elevated because the NA clearance was reduced in IMO
rats. Dissociation between changes of plasma NA and DHPG levels can indicate
changes in neuronal reuptake of NA. We found such a dissociation in humans
during bicycle ergometry suggesting a reduced NA reuptake. DOPA circulates
in plasma at higher levels than NA. During stress, increased sympathoadrenal
outflow stimulates DOPA synthesis and release into the circulation supporting
the view that changes in plasme DOPA levels reflect in vivo changes in
CA synthesis.
Thus, the presented data demonstrate the importance of simultaneous
measurement of plasma CA levels, CA synthesis, release, reuptake, and degradation
for evaluation of SAS activity in basal and stress conditions of the organism.
(Fig. 10, Ref. 56.)
Key words: CA synthesis, release, spillover, reuptake, degradation,
SAS activity, CA enzyme gene expression, plasma DOPA, stress.
Bratisl Lek Listy 1996; 97: 7283
THE EFFECT OF HYPEROSMOLAR MANNITOL ON THE LEFT VENTRICULAR FUNCTION IN ESSENTIAL HYPERTENSION
PECHAN, J., POVINEC, P., BRANSKA, E.
The left ventricular function of the heart was examined by means of
the method of equilibrium-radionuclide ventriculography in 40 patients
with essential hypertension (EH) 20 patients in stage I (H1), 20 patients
in stage II (H2) according to WHO criteria and in 18 normotensives (N).
The examination was performed at rest and immediately after stress by intravenous
infusion of hyperosmolar mannitol. At rest, the parameters of global systolic
and diastolic functions of the left ventricle in normotensives do not differ
significantly from the values in both groups of hypertensives. The global
ejection fraction (GEF), peak ejection rate (PER) and peak filling rate
(PFR) were in H2 significantly lower than in H1. Sectorial ejection fraction
(SEF) in the apicoseptal area is in H2 significantly lower than in H1 and
N. After infusion of hyperosmolar mannitol the GEF and PFR increased in
N and H1 only. When comparing all groups after infusion of mannitol the
PFR in H2 is significantly lower also in comparison with N with the tendency
(significant limit) to lower values of GEF and PER. PER and PFR were significantly
lower and the end-diastolic volume (EDV) was significantly higher in H2
in comparison with H1. SEF was significantly lower in H2 in comparison
with N in 3 out of 9 sectors and in comparison with H1 in 8 out of 9 sectors.
The infusion of hyperosmolar mannitol reveals subclinical disturbances
of the diastolic and partially also of the systolic function of the left
ventricle in stage II of EH which is very useful for diagnosis and treatment.
(Tab. 4, Fig. 3, Ref. 22.)
Key words: left ventricular function, radionuclide ventriculography,
essential hypertension, mannitol.
Bratisl Lek Listy 1996; 97: 8489
COMPLEX PREVENTION OF POSTOPERATIVE THROMBOSIS
LABAS, P., VRTIK, L., SVEC, R., SASVARY, F.
Thromboembolic disease with its high mortality and morbidity is currently
one of the most serious postoperative complications. Its occurrence in
high-risk patients in surgical wards is 2550 %. Since 1979, the authors
have examined 160 risk patients in whom no prevention had been performed.
In this group of patients they detected the occurrence of profound venous
thrombosis by means of the accumulation fibrinogen test, targeted phlebography
under skiascopic control. At the same time the clinical symptomatology
was followed in detail. Since the thrombosis is a multifactorial process,
the effective preventive measures must affect and normalize as many disturbed
homeostatic processes as possible. Into the group of 176 high-risk patients,
the authors introduced a complex prevention into the surgical routine residing
in classical low-dose heparinization by 5000 u. s.c. with the first dose
administered 2 hours prior to surgery, peroperational haemodilution with
the administration of minimally 500 ml of Dextran and in per-operation
administration of antiaggregants (Acylpyrin). By means of this tactic,
the greatest antithrombotic effect is brought about peroperatively and
in the first postoperative hours while the patient is protected minimally
5 to 7 postoperative days. Both peroperative and postoperative procedures
are monitored by means of a complex haemocoagulation examination of the
basic 10 haemocoagulation factors. The occurrence of thrombosis in patients
without prevention with minimally 5 thrombogenetic risk factors during
the control by means of the accumulation fibrinogen test was 32.4 % and
during the control by means of targeted phlebography is 24 %. The differences
are not statistically significant. In the group of patients with prevention
the occurrence is 5.6 %. In this group the screening is represented by
the accumulation fibrinogen test and its positivity is verified by its
localization by means of selective phlebography. The occurrence of deep
vein thrombosis in the group with prevention and in the control group is
statistically highly significant p>0.0005.
Haemocoagulation examination is aimed at the determination of the normalization
impact of prevention on the state of hypercoagulation ability associated
with the depression of spontaneous fibrinolysis in patiets without prevention.
The thrombi detected in patiens with prevention are localized in short
segments of crural veins. Clinically more significant bleeding in the group
of patients with prevention occurred only in 2 patients, i.e. in 1 %. Complex
multifactorial prevention is not only simple and safe for patients, but
also highly effective in the group of patients with high risk of postoperative
thrombosis. The clinical diagnosis is unreliable and misleading with low
sensitivity and specificity. (Tab. 2, Fig. 2, Ref. 28.)
Key words: postoperative thrombosis prevention, diagnosis.
Bratisl Lek Listy 1996; 97: 9095
TIME FACTOR AND CAUDA EQUINA SYNDROME
SULLA, I.
Cauda equina syndrome is a rare but potentially catastrophic complication
of lumbar disc disease. In spite of properly performed surgical decompression,
the outcome is mostly unsatisfactory. One of the important factors influencing
the recovery of motor function of the lower extremities, sensation, bladder
and rectum control, sexual function, as well as working ability is thought
to be the duration of cauda equina compression. The evaluation of data
obtained in a group of 58 persons (21 women and 37 men) operated upon for
discogenic cauda equina syndrome in the period of time from January 1,
1982 to December 31, 1991 did not confirm this opinion. (Tab. 7, Ref.
23.)
Key words: Cauda equina syndrome, duration of compression.
Bratisl Lek Listy 1996; 97: 9699
HYLACOMBUN IN INFLAMMATORY BOWEL DISEASES
PRIKAZSKA, M., LETKOVICOVA, M.
Treatment of non-specific bowel inflammation (NBI) particularly of Crohns
disease (MD) and ulcerative colitis is very complicated, especially because
of the fact, that in spite of artial successful findings, the etiology
of both main diseases of this group remain unknown. Nevertheless, manifestations,
particularly in MC vary, often unexpectedly and surprisingly. Different
medical teams eleborate therapeutic schedules, but none of them has been
accepted world-wide. As it is still possible to state that NBI is untreatenable
by drug therapy, even the surgical removal of the affected part of the
bowel does not protect against the relapse, it may indicate that no therapeutical
approaches are sufficient at present. Using drug therapy, the biochemical
chain of numerous inflammatory mediators is being tried to be disrupted.
Despite the advances achieved, there are still many difficulties related
to drug therapy. It is necessary to take into account the fact that the
lock of knowledge in causative therapy and failure, poor response to initial
therapy lead to the use of more new drugs. Therefore a careful consideration
of every used or recommended drug is necessary.
The principle of using Hylacombun (Merckle) in therapy was not applied
due to the presumption of influencing the disease fundamentally, but due
to an effort to reduce some symptoms of the disease, which detoriorate
the life quality of patients.
Data given by patients in questionnaires as well as biochemical and
haematological parameters were evaluated statistically. Besides the commonly
used Student t-test, we used Box and Whisker plots, linear trend analysis
and the method of 9 aggregation numbers to follow both dynamics of the
disease and drug effect. Laboratory, as well as the questionnaire data
were equilibrated and graphically illustrated by the spline method. We
found out that Hylacombun was effective in all patients. Subjective improvement
was shown after 10 days of therapy, stabile improvement after 2 months.
(Tab. 3, Fig. 7, Ref. 9.)
Key words: non-specific bowel inflammation, Hylacombun tabl. (Merckle),
statistical analysis.
Bratisl Lek Listy 1996; 97: 100105
THE THERAPY IN CHOLEDOCHOLITHIASIS IN THE ERA OF LAPAROSCOPIC CHOLECYSTECTOMY
PROCHOTSKY, A., PECHAN, J., LABUDA, M.
Laparoscopic cholecystectomy (L-CHE) is currently considered to be the
optimal standard in the therapy of cholecystolithiasis. However, it is
choledocholithiasis which is problematic, especially the timing of the
solution in relation to L-CHE. In general, the opinion predominates that
in preoperatively verified choledocholithiasis the ERCP with EPS and extraction
of choleliths should be performed 2428 hours prior to the elective L-CHE.
Surgical removal of choleliths from the main biliary ducts is indicated
only in a small group of patients. The authors of the study reflect upon
the current trends of the choledocholithiasis therapy in the era of laparoscopic
cholecystectomy. They present their own set of patients and recommend the
procedure of the choledocholithiasis therapy concommitted with cholecystolithiasis
with the subjective of the full use of endoscopic methods in the therapy
of this disease. (Ref. 14.)
Key words: laparoscopic cholecystectomy, choledocholithiasis, endoscopic
papilloshincterotomy.
Bratisl Lek Listy 1996; 97: 106108