Janusz Blaszczyk | Nencki Institute of Experimental Biology (original) (raw)

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Papers by Janusz Blaszczyk

Brain, Behavior, and Immunity, 2008

Bacterial endotoxin (lipopolysaccharide; LPS) evokes in rodents an adaptive sickness behavior. It... more Bacterial endotoxin (lipopolysaccharide; LPS) evokes in rodents an adaptive sickness behavior. It also produces changes in stress hormones secretion and activity of brain serotonergic and noradrenergic systems that have been implicated in stress responses, fear, and anxiety. Acoustic startle reflex (ASR) is regarded as a protective behavioral response that is enhanced in threatening situations or following an aversive event, and it can be modulated by physiological and emotional state of an animal. Effects of intraperitoneal injections of LPS on ASR, prepulse inhibition (PPI), locomotor activity in open field, and blood plasma corticosterone concentration were studied in lines of mice that display high (HA line) or low (LA line) swim stress-induced analgesia and also differ in emotional behaviors, including the magnitude of ASR. In both lines LPS produced robust sickness behavior, as evidenced by a decrease in locomotion and body weight, and an increase in corticosterone concentration. However, in neither line LPS injections affected responses to acoustic stimuli as assessed by the ASR and PPI magnitudes. The findings suggest that in sickness behavior induced by LPS the protective responses to salient environmental stimuli are not impaired. The significance of this finding for the concept of sickness behavior is discussed.

Gerontologia Polska, 2005

BioMed Research International, 2016

Purpose. The aim of this study was to evaluate the possibility of using static posturography in t... more Purpose. The aim of this study was to evaluate the possibility of using static posturography in the assessment of sensorimotor gating. Subjects and Methods. Fourteen subjects took part in the experiment. The inhibitory mechanisms of startle reflex were used as the measure of sensorimotor gating. It was evoked by a strong acoustic stimulus (106 dB SPL, 40 ms) which was preceded by the weaker similar signal (80 dB SPL, 20 ms). A stabilographic platform was used to measure sensorimotor gating. Results. Results of static posturography show that the postural sway caused by the reaction to a strong acoustic stimulus is significantly smaller when this stimulus is preceded by the signal of lower intensity (prepulse). Such assessment is only possible in eyes open conditions. Conclusions. Static posturography can be simple and effective method used for diagnosis of sensorimotor gating in humans.

Acta Neurobiologiae Experimentalis, 2014

Directional characteristics of postural sway and their impact on postural stability control (PSC)... more Directional characteristics of postural sway and their impact on postural stability control (PSC) still need to be clarified. To assess the directional characteristics of PSC, center-of-pressure (COP) while standing quiet was recorded and analyzed in 46 young healthy subjects. The participants completed five 60-s trials with 'eyes open' and five with 'eyes closed'. The control asymmetry was characterized using three standardized COP measures: mean sway velocity (V), sway ratio (SR), and sway directional index (DI). The COP data were low-pass filtered at 10 Hz. In such conditions the V, SR and DI revealed consistent and unique differences in both the anteroposterior (AP) and the mediolateral (ML) controls. Each of the COP measures showed the involvement of different neuromuscular and biomechanical mechanisms in the stabilization of standing posture. The DI documented a very stable proportion between frontal and saggital controls, with roughly 60% of the swaying movements being performed in the AP direction. The AP DI was significantly higher in comparison with the ML value (0.71±0.04 vs. 0.55±0.06). This proportion remained at the same level in both experimental groups and it was only slightly affected by the visual conditions. Analysis of the SR confirmed that to maintain stable stance the neuromuscular system must allocate 50% more effort to control AP stability. The results also documented gender-related differences in postural stability. Generally the female subjects appeared to have lower postural stability as evidenced by higher COM and COP velocities. Consequently the higher SR values observed in the female group indicate a need for higher neuromuscular efforts to maintain stable posture. The introduced here set of COP measures proved to be a valuable standard for static posturography, creating the opportunity for improved and reliable assessment of postural stability.

$Research paper thumbnail of Postural stability and fractal dynamics$

Acta neurobiologiae experimentalis, 2001

Methods of non-linear dynamics and deterministic chaos may provide us with effective quantitative... more Methods of non-linear dynamics and deterministic chaos may provide us with effective quantitative descriptors of the dynamics of postural control. The goal of this study was to introduce a new measure, which would allow to determine the fractal structure of posturographic signals and to measure the effect of the loss of visual feedback information in postural control. The results of the study show that fractal dimension (Df) is a very useful, reliable and sensitive measure of the complexity of posturographic signals. Therefore Df can be used for the evaluation of postural stability and its changes due to pathology or an age-related decline.

Mutation Research/Fundamental and Molecular Mechanisms of Mutagenesis, 2011

j o u r n a l h o m e p a g e : w w w . e l s e v i e r . c o m / l o c a t e / m o l m u t C o m... more j o u r n a l h o m e p a g e : w w w . e l s e v i e r . c o m / l o c a t e / m o l m u t C o m m u n i t y a d d r e s s : w w w . e l s e v i e r . c o m / l o c a t e / m u t r e s Impaired nucleotide excision repair pathway as a possible factor in pathogenesis of head and neck cancer a b s t r a c t

Acta neurobiologiae experimentalis, 2014

Journal of Biomechanics, 2000

Although the identi"cation and characterization of limb load asymmetries during quiet standing ha... more Although the identi"cation and characterization of limb load asymmetries during quiet standing has not received much research attention, they may greatly extend our understanding of the upright stance stability control. It seems that the limb load asymmetry factor may serve as a veridical measure of postural stability and thus it can be used for early diagnostic of the age-related decline in balance control. The e!ects of ageing and of vision on limb load asymmetry (LLA) during quiet stance were studied in 43 healthy subjects (22 elderly, mean age 72.3$4.0 yr, and 21 young, mean age 23.9$4.8 yr). Postural sway and body weight distribution were recorded while the subject was standing on two adjacent force platforms during two 120 s trials: one trial was performed with the eyes open (EO), while the other trial was with the eyes closed (EC). The results indicate that LLA was greater in the old adults when compared with the young control subjects. The LLA values were correlated with the postural sway magnitudes especially in the anteroposterior direction. Eyes closure which destabilized posture resulted in a signi"cant increase of body weight distribution asymmetry in the elderly but not in the young persons. The limb load di!erence between EO and EC conditions showed a signi"cantly greater e!ect of vision on LLA in the elderly compared to the young subjects. The observed di!erences in the LLA may be attributed to the decline of postural stability control in the elderly. Ageing results in the progressive decline of postural control and usually the nervous system requires more time to complete a balance recovery action. To compensate for such a de"ciency, di!erent compensatory strategies are developed. One of them, as evidenced in our study, is preparatory limb unload strategy (a stance asymmetry strategy) which could signi"cantly shorten reaction time in balance recovery.

Journal of Biomechanics, May 1, 2009

Research that evaluated both static and dynamic stability was performed, to clarify the impact of... more Research that evaluated both static and dynamic stability was performed, to clarify the impact of excessive body weight on postural control. The spontaneous center of foot pressure (CP) motion during quiet stance and a range of forward voluntary CP displacements were studied in 100 obese, and 33 lean women. Characteristics of postural sway were acquired while the subjects were standing quiet on a force plate with eyes open (EO) and with eyes closed (EC). Their anterior range of CP voluntary displacements was assessed upon a range of maximal whole body leanings which were directed forward. A substantial reduction of postural sway was observed in all patients which had increased body weight. Main postural sway parameters i.e., the total path length as well as its directional components were negatively correlated with the body mass and body mass index (BMI). The range of a whole body voluntary forward leaning, did not exhibit any significant change in patients with an obesity grade of I and II. Such a deficit was, however, found in subjects with a body mass index above 40. In conclusion, the increased body weight imposed new biomechanical constraints, that resulted in functional adaptation of the control of the erect posture. This functional adaptation was characterized by a reduced postural sway associated with a substantial reduction of the dynamic stability range in subjects with BMI440.

Acta Neurobiologiae Experimentalis, 2011

The objective of this study was to investigate whether a 3-month weight reduction treatment influ... more The objective of this study was to investigate whether a 3-month weight reduction treatment influences gait in obese women. Gait parameters were measured on a 10-m long instrumented walkway consisted of very soft wire netting fixed to the floor. The study group included 52 obese women 37,3±11,2; BMI: 30,8 kg/m 2 ; 36,5±4,8). Anthropometric measurements were taken, BMI was calculated, body composition was analyzed, selected kinematic gait parameters [mean velocity of gait, number of gait cycles per minute (cadence), stride length, gait cycle (stride time), stance time, swing time and double support time] were measured at baseline and after a 3-month weight loss treatment. Average weight reduction of 7,4% of initial body weight resulted in characteristic changes of gait parameters among obese women: they walked faster, made more steps per 1 minute, stride length and swing duration increased, whereas cycle time, stance and double support phases were shortened. Reduction of body mass in obese individuals has positive effects on gait kinematics. Even though the treatment lasted only 3 months it resulted in significant changes of all gait parameters tested.