Biomedical subjects

K Javorka

Publications and source records attributed to K Javorka.

At least 19 recordsLinked to original sources

PubMed2005

Cystic dysplasia of the rete testis. Case report.

Cystic dysplasia of the rete testis (CDRT) is a very rare cause of a paediatric scrotal mass often associated with renal and other genitourinary tract anomalies. These complex malformations are probably due to a developmental defect of the mesometanephric system during embryogenesis. A case of asymptomatic scrotal swelling in a 4-year-old boy is presented. Ultrasonography, showed a cystic lesion of the left testis associated with absence of the left kidney. Orchiectomy was performed because of extensive gonad involvement. Pathologic examination revealed multiple, anastomosing, irregular cystic spaces of varying sizes and shapes predominantly located in the region of the rete testis. The cysts had spread irregularly, displacing the testicular parenchyma, which was subsequently compressed under the tunica albuginea. Preoperative diagnosis of CDRT is easy if age, precise localisation, characteristic ultrasonographic features and other genitourinary malformations are considered. Other paediatric cystic lesions should be included in the differential diagnosis. It is possible to cure CDRT by orchiectomy or by conservative treatment. Nowadays the later option is preferred, but diagnosis of CDRT must be precisely established and followed by careful monitoring.

Child, Preschool↗

PubMed2005

Surfactant lung lavage using asymmetric high-frequency jet ventilation followed by conventional ventilation in rabbits with meconium aspiration.

BACKGROUND: Severe impairment of lung functions in meconium aspiration syndrome (MAS) often needs the application of combined therapeutic approach. In our recent study, surfactant lung lavage during asymmetric high-frequency jet ventilation (HFJV) removed more meconium than surfactant lavage during conventional ventilation, however, after the lavage excessive CO2 elimination was observed during HFJV. OBJECTIVES: We hypothesized that the combination of asymmetric HFJV during surfactant lung lavage and conventional ventilation in the post-lavage period may be of benefit in a rabbit model of MAS. METHODS: Suspension of human meconium in saline (25 mg/ml, 4 ml/kg) was instilled into the tracheal tube of conventionally ventilated (frequency, f, 30/min, inspiration time, Ti, 50%) anesthetized rabbits to cause a respiratory failure. Animals were then lavaged (10 ml/kg in 3 portions) with diluted surfactant (Curosurf, 100 mg of phospholipids/ml) or saline during asymmetric HFJV (f, 300/min, Ti, 70%). After the lavage, animals were ventilated conventionally (f, 30/min, Ti, 50%) for next 1 hour. RESULTS: Surfactant lung lavage during asymmetric HFJV removed more meconium pigments and solids than saline with HFJV (p < 0.05 or p < 0.01, respectively). Moreover, application of asymmetric HFJV facilitated the lavage fluid removal in both groups. In the post-lavage period, improved oxygenation, lung compliance, right-to-left pulmonary shunts, and reduced ventilatory requirements were found in the surfactant group (p < 0.05), while pCO2 was kept in the normal range. CONCLUSIONS: Surfactant lung lavage by asymmetric HFJV followed by conventional ventilation is advantageous combination in rabbits with MAS and may be tested in neonatal MAS (Tab. 2, Fig. 2, Ref. 12).

Animals↗

PubMed2004

Effects of acute normovolemic haemodilution on cardiorespiratory changes in hyperthermia and its physical treatment.

As only one experimental study examining the effects of haemodilution on circulatory responses to hyperthermia has so far been published and there is no information on respiratory responses to hyperthermia during haemodilution or anaemia, this paper studied the effects of acute normovolemic haemodilution on cardiorespiratory changes during 42 degrees C hyperthermia and its recovery by body surface cooling in 16 anaesthetized adult rabbits. The animals were divided into two groups: haemodiluted group (Hct = 18.6 +/- 0.4%) and control group (Hct = 41.1 +/- 0.9%). In the haemodiluted group, acute normovolemic haemodilution was induced by 60% replacement of total blood volume with dextran. Haemodilution produced significant increases in minute volume (V(E), p < 0.02), heart rate (HR, p < 0.02) and central venous pressure (CVP, p < 0.02), but there was no significant change in mean arterial pressure (MAP). Hyperthermia caused significant increases in V(E) and HR in both the groups; however, V(E) and HR values were significantly higher in the haemodiluted group compared to the controls. CVP decreased (p < 0.05) during 42 degrees C hyperthermia only in the controls in the panting phase. MAP did not significantly change during over-heating in controls, but it significantly (p < 0.02) rose in the haemodiluted group. In the recovery phase, cooling led to significant decreases in HR and MAP in both the groups and to further increases in V(E) (p < 0.05) in controls, whereas V(E) decreased in the haemodiluted animals. There were found no significant cardiorespiratory differences between the two groups during cooling. Hyperthermia was accompanied by the higher values of minute volume and heart rate in the haemodiluted animals, indicating a greater activation of the respiratory and cardiovascular systems, which could result in diminished functional cardiorespiratory reserve and a higher risk of respiratory and circulatory failures in haemodiluted/anaemic animals during hyperthermia. In the phase of recovery of the body temperature there were no significant cardiorespiratory differences found between the two groups.

Animals↗

PubMed2003

Lung lavage using high-frequency jet ventilation in rabbits with meconium aspiration.

AIM: To determine the efficacy of the expulsion effect of high-frequency jet ventilation (HFJV) on meconium clearance from the airways in comparison with conventional suctioning in adult rabbits with meconium aspiration. METHODS: Experiments were carried out on tracheotomized, anaesthetized and paralysed adult rabbits. A suspension of human meconium in saline (25 mg ml(-1), 4 ml kg(-1)) was instilled into the tracheal cannula. When respiratory failure developed, saline lavage (10 ml kg(-1) in 3 portions) was performed during conventional ventilation or by means of the inpulsion and expulsion regime of HFJV. Animals were further ventilated for 2 h with either conventional ventilation or HFJV. RESULTS: There was no significant difference between groups in the amount of meconium recovered by lavage. Compared to conventional ventilation, the application of HFJV enhanced the elimination of carbon dioxide, increased lung compliance and diminished right-to-left shunts after 30 min of ventilatory treatment. Oxygenation also improved during HFJV, although this was not a consistent finding during the ventilation period. CONCLUSION: HFJV improved gas exchange, lung compliance and reduced right-to-left pulmonary shunts, but saline lung lavage by HFJV was not found to be more efficient than lavage during conventional ventilation in rabbits with meconium aspiration.

Animals↗

PubMed2002

Heart rate recovery after exercise: relations to heart rate variability and complexity.

Physical exercise is associated with parasympathetic withdrawal and increased sympathetic activity resulting in heart rate increase. The rate of post-exercise cardiodeceleration is used as an index of cardiac vagal reactivation. Analysis of heart rate variability (HRV) and complexity can provide useful information about autonomic control of the cardiovascular system. The aim of the present study was to ascertain the association between heart rate decrease after exercise and HRV parameters. Heart rate was monitored in 17 healthy male subjects (mean age: 20 years) during the pre-exercise phase (25 min supine, 5 min standing), during exercise (8 min of the step test with an ascending frequency corresponding to 70% of individual maximal power output) and during the recovery phase (30 min supine). HRV analysis in the time and frequency domains and evaluation of a newly developed complexity measure - sample entropy - were performed on selected segments of heart rate time series. During recovery, heart rate decreased gradually but did not attain pre-exercise values within 30 min after exercise. On the other hand, HRV gradually increased, but did not regain rest values during the study period. Heart rate complexity was slightly reduced after exercise and attained rest values after 30-min recovery. The rate of cardiodeceleration did not correlate with pre-exercise HRV parameters, but positively correlated with HRV measures and sample entropy obtained from the early phases of recovery. In conclusion, the cardiodeceleration rate is independent of HRV measures during the rest period but it is related to early post-exercise recovery HRV measures, confirming a parasympathetic contribution to this phase.

Adult↗

PubMed2002

Do the oscillations of cardiovascular parameters persist during voluntary apnea in humans?

The aim of this study was to ascertain the persistence of heart rate and blood pressure oscillations at the onset of voluntary apnea in humans and to assess the dependence of the fluctuations parameters on the chemoreceptor activity. In 24 young subjects (10 males, 14 females, mean age 20.4 years) heart rate (represented by its reciprocal value--RR-intervals), systolic blood pressure (SBP) and diastolic blood pressure (DBP) during controlled breathing (CB) of atmospheric air and oxygen followed by apnea were recorded continuously. The cosine functions were then fitted by nonlinear regression analysis to the heart rate, SBP and DBP oscillations during CB and at the onset of apnea. The parameters of oscillations were different during atmospheric air breathing compared to oxygen breathing. During oxygen breathing there was an increase of the RR-interval oscillations--relative bradycardia and enhanced magnitude of respiratory sinus arythmia. During apnea, the base level of the blood pressure oscillations was higher after breathing of atmospheric air compared to oxygen breathing. At least one cosine-like wave oscillation was present at the onset of apnea in the heart rate, SBP and DBP and the second wave was present in all assessed parameters in at least 70% of recordings. The oscillations in RR-intervals are, to some extent, independent of blood pressure oscillations. No significant gender differences were found either in the duration of breath holding or in the RR and SBP oscillations parameters.

Adolescent↗

PubMed2001

'Respiratory' oscillations of cardiovascular parameters during voluntary apnea.

The aim of this study was to ascertain the persistence of heart rate and blood pressure oscillations at the onset of voluntary apnea in humans. In 24 young subjects (10 males, 14 females, mean age 20.4 years) RR intervals, systolic blood pressure (SBP) and diastolic blood pressure (DBP) during controlled breathing (CB) of atmospheric air followed by voluntary apnea on FRC level were recorded continuously. The cosine functions were then fitted by nonlinear regression analysis to heart rate, SBP and DBP oscillations during CB and at the onset of apnea. During apnea, the changes of base of RR intervals indicate primary tachycardic reaction followed by a decrease in heart rate. The base of the blood pressure oscillations was higher (hypertensive reaction) in apnea. At least one cosine-like wave oscillation was present at the onset of apnea in heart rate, SBP and DBP and the second wave was present in all assessed parameters at least in 70% of recordings. There were no significant gender differences neither in the duration of breath holding nor in the RR and SBP oscillations parameters.

Adult↗

PubMed2001

[The autonomic nervous system and hypertension].

It was shown that dysregulation of the cardiovascular system plays an important role in the development of arterial hypertension. Sympathetic drive can be increased mainly in cases of borderline and essential hypertension. The rise in sympathetic activity is not well balanced by the adequate increase in parasympathetic activity, even the PS tone is diminished. Relative sympathotony can occur beside the absolute sympathotony due to the decrease in the PS tone with normal or quantitatively less diminished sympathetic drive. The cause of the ANS activity dysbalance remains unknown. Probably there exist disorders of generator and modulator activities in higher levels of CNS, baroreceptor regulation and other peripheral (humoral and other) mechanisms. Adequate and appropriate recording of different cardiovascular parameters mainly during activation of ANS by maneuvers (orthostasis, Valsalva, etc.) is necessary. Beat-to-beat registrations of blood pressure (e.g. by Penáz method FINAPRES), heart rate (RR intervals) are necessary for the evaluation of short term blood pressure and heart rate fluctuations. Important information about S/PS activities and the balance in heart rate regulation can be achieved by spectral and non-linear analysis of the HR variability. Regular physical aerobic exercise increases the parasympathetic tone and is beneficial for restoration of the disordered S/PS balance in young hypertonics. It can be used as non-pharmacological treatment of arterial hypertension.

Autonomic Nervous System↗

PubMed2000

[Evaluation of heart rate variability and its usefulness].

The article presents a review of the method of the evaluation of the heart rate variability using spectral analysis and of the cardiovascular regulation evaluation using cardiovascular tests. It refers about the application in physiological research. The importance of the heart rate variability examination will increase in the future according to the sensitivity, noninvasivity and precision.

Autonomic Nervous System↗

PubMed2000

[Diagnosis and treatment of functional disorders of the lower urinary tract in younger men].

BACKGROUND: Functional disorders of the lower urinary tract can manifest by different symptoms. This could be caused by inaccurate diagnosis and non-causal treatment in young men. Urodynamics is helpful in the differential diagnosis and treatment of such cases. OBJECTIVES: Examination of lower urinary tract functions in young men and causal treatment of both bladder neck obstruction or impaired bladder. METHODS: In a prospective study, a group of 38 young men were treated at mean age of 42 years (range 19-50 yrs). Chronic abacterial prostatitis was treated in all cases unsuccessfully. Patients with positive urinary infection, previous surgery of the lower urinary tract and neurogenic bladder were excluded. Urodynamics confirmed a bladder neck obstruction or impaired bladder, the symptom score revealed subjective difficulties (maximum 35 points). Patients with the obstruction underwent transurethral incision of the bladder neck. Patients with impaired bladder were administrated with distigmine bromid (Ubretid) 5 mg for 1 year, every other day. All patients were re-examined one year following the treatment. RESULTS: Bladder neck obstruction occurred in 18 cases, and impaired bladder in 20 cases. Significant differences were found in relation to age (47 vs. 31 years, p < 0.01) and detrusor pressure at maximum flow (62 vs. 30 cmH2O, p < 0.01). There were no differences in peak flow rate (9 vs. 10 ml/s, p = 0.75), symptom score (19 vs. 18, p = 0.46), residual urine (45 vs. 100, p = 0.08) and maximum cystometric capacity (341 vs. 383 ml, p = 0.10). Transurethral bladder neck incision or distigmine administration improved the symptom score by 68.4% vs. 33.3%, peak flow rate 50.0% vs. 23.1% and residual urine 100% vs. 75%. CONCLUSIONS: Treatment of lower urinary tract disorders is successful in causal treatment of bladder neck obstruction and impaired bladder. (Tab. 2, Fig. 2, Ref. 12.)

Adult↗

PubMed2000

[Diagnosis of intrinsic urethral sphincter insufficiency in women].

OBJECTIVE: Evaluation of intrinsic sphincter deficiency (ISD) according to the urethral leak point pressure in female population with stress urinary incontinence. DESIGN: Prospective clinical study. SETTING: Department of Urology, Jessenius School of Medicine Comenius University Martin, Slovak Republic. METHODS: Study population compromise of 204 females with lower urinary tract symptoms. Exclusion criteria were neurogenic bladder and unstable bladder. Valsalva leak point pressures were evaluated (VLPP). ISD was defined if VLPP below 65 cm H2O has been occurred. Pad weighing test (PWT) was positive after leakage of 2 g per hour and more. RESULTS: Stress urinary incontinence was in 134 and continence in 70 cases (control group). The first stage of incontinence was in 83, the second stage in 45 and the third stage in 6 cases of incontinence group. ISD has been occurred in 14 cases (10.5%), 8 cases with the second stage and 6 cases with the third stage. The best correlation was between VLPP and PWT, symptoms of incontinence and age of patients. All ISD cases underwent antiincontinent surgery with urethral suspension, some years ago. CONCLUSION: ISD has been risen in the second stage (6%) and the third stage (4.5%), also, in the female population with stress urinary incontinence.

Adolescent↗

PubMed1997

Changes in parameters of mechanics of breathing during high-frequency jet ventilation: what is the cause?

In experiments on 51 healthy anaesthetized and paralyzed rabbits the changes in parameters of mechanics of breathing during high frequency jet ventilation (HFJV) were determined and the mechanisms responsible for these changes were investigated. In the first series of experiments with two groups of animals ventilated by HFJV with relative inspiratory time ti=0.5 and ti=0.7 airway resistance (Raw) after 5 h of HFJV in the ti=0.5 group increased from 1.14+/-0.05 to 2.31+/-0.09 kPal(-1) x s (P < or = 0.001), in the ti=0.7 group from 1.22+/-0.04 to 1.78+/-0.08 kPal(-1) x s (P < or = 0.01). Dynamic compliance (Cdyn) decreased in the ti=0.5 group from 0.041+/-0.004 to 0.017+/-0.001 l x kPa(-1) (P < or = 0.01) and in the ti=0.7 group from 0.034+/-0.003 to 0.022+/-0.002 l x kPa(-1) (P < or = 0.01). In the second series of experiments a group of animals was ventilated by HFJV after cervical vagotomy. The deterioration of Raw and Cdyn was significantly reduced in vagotomized rabbits in comparison to the controls without vagotomy. Finally, the study of phospholipid content in bronchoalveolar lavage fluid revealed no significant differences after 5 h of artificial ventilation or spontaneous breathing. These data indicate that HFJV results in changes in the parameters of mechanics of breathing in healthy lungs, which may be attenuated, but not fully eliminated, by bilateral cervical vagotomy. The decrease in Cdyn and increase in Raw are probably not due to changes in the pulmonary surfactant content.

Animals↗

PubMed1996

[Cardiovascular and hemodynamic changes after artificial pulmonary ventilation].

The cardio-respiratory interactions include mechanical, reflex and humoral mechanisms. However, in the organism they mutually overlap, thus mating their separate investigation is problematic. Mechanical effects of conventional artificial ventilation (AV) and high frequency ventilation (HFV) are elicited by increased intrapulmonary pressure during lung inflation, as well as during application of positive end expiratory pressure (PEEP). The increase in intrapulmonary pressure compresses the pulmonary vessels and increases the pulmonary vascular resistance. These changes deteriorate the right ventricular function. Mechanical factors are responsible for the fall of the left ventricular (LV) filling, stroke volume and alteration of the LV preload and afterload. LV filling is decreased during artificial ventilation (AV) owing to the shifting of blood from the central to the peripheral circulation, and to the rise in pulmonary vascular resistance. Application of positive intrathoracic pressure during ventricular ejection phase can diminish LV afterload and increase the cardiac output. This effect is striking in LV failure. The reflex effects of artificial ventilation are due to the activation of baroreflexes and pulmo-vagally cardiac and vasoactive reflexes. Activation of these reflexes depends on the level and characteristic of the pressure in the airways, lungs, heart and vessels. Humoral effects of AV on the cardiovascular system and hemodynamics are triggered by lung expansion, circulatory changes, and they result in a release of vasoactive substances from lung parenchyma. (Fig. 5, Ref. 45.)

Hemodynamics↗

PubMed1996

Contribution to occupational angiopathy diagnosis using special examination method.

The authors presented 1642 cases of professional diseases caused by vibrations (VD) and 435 cases of extremity overload disease (EOD) diagnosed in the years 1974-1993. In addition to the standard rheoplethysmography there were evaluated the results of digital laser Doppler flowmetry (Moor instruments, UK) in 104 workers exposed to vibration (EV) and 25 controls with the age and smoking habit standardisation. In the selected subgroup were used continual measurements of digital blood pressure (Finapress, Ohmeda), digital LD flux and speed and the measuring of digital skin and central body temperature simultaneously. The records before and after 10 min of local cooling test (Rejsek method) and postocclusive hyperemic tests were summarized (computer evaluation, program STATGRAPHICS, T-test). Vasoconstriction to local cooling persisted in EV for longer time. The records of digital skin flux and speed, digital blood pressure reactions of EV were significantly different (EV/controls) also in the 10th min after cooling. Postocclusion hyperemic tests revealed good functional capacity also in EV. Advantages and disadvantages of methods were discussed. The results found by non-invasive methods in VD were in good relation to images obtained by means of radionuclides (clearance and cumulative tests). Cumulative tests (after 99m--pertechnetate i.v.) can be used in the selected differential diagnostic cases of angiopathies to help to distinguish degree of angiospastic and angioparalytic changes in the hands of VD, and also in special cases at angiopathies connected with EOD.

Adult↗

PubMed1996

[Pulmonary surfactant].

Study of the pulmonary surfactant system has brought important information about its composition, metabolism and functions in the last decades. Besides phospholipids an important role is played by surfactant proteins (SP-A, B, C, D). These proteins aid not only the reduction of the surface tension of the alveoli, but they are involved in regulation of surfactant synthesis, secretion and in local immune defense in the lungs. Impairment of surfactant was found not only in premature newborns (IRDS), but also in cases of meconium aspiration, pneumonia and in other lung diseases in adults. Therapy by stimulation of surfactant synthesis and secretion and by intrapulmonary application of exogenous surfactant was proved effective in therapy of surfactant-deficiencies.

Adult↗

PubMed1996

Cardiorespiratory parameters and respiratory reflexes in rabbits during hyperthermia.

The effects of different body temperature (BT) on the respiratory and cardiovascular parameters and respiratory reflexes were studied in 33 anaesthetized adult rabbits. Hyperthermia elicited panting with mean panting respiratory rate 199 +/- 14 x min-1 in all anaesthetized rabbits. Significant correlations between BT and frequency of breathing (positive), heart rate (positive) or tidal volume (negative) were found. Cooling was accompanied by considerable arterial hypotension. Duration of the Hering-Breuer reflex (HB) was reduced by the rise of BT. Intensity of the reflex (assessed as the ratio of the apnoeic pause to the mean duration of the previous 5 breaths) was unchanged up to the body temperature eliciting panting (41.15 +/- 0.08 degrees C) when it was greatly diminished. Defensive airway reflexes were also changed in hyperthermia. The duration as well as the intensity of nasal apnoea (Kratschmer's reflex) and laryngeal chemoreflex apnoea were decreased. The intensities of respiratory efforts in sneezing and laryngeal coughing were reduced. The expulsive reactions evoked by mechanical stimulation of the larynx were replaced by very shortlasting inhibition of breathing during panting. The results indicate that reflex control of breathing via the Hering-Breuer reflex and the ability to eliminate irritants from the airways are diminished during hyperthermia and panting in anaesthetized rabbits.

Animals↗

PubMed1994

Defensive reflexes of the respiratory system in anaesthetized rabbits during high frequency jet ventilation.

The defensive airway reflexes during high frequency jet ventilation (HFJV) were studied in anaesthetized, non-vagotomized (n = 16) and vagotomized (n = 11) rabbits. The animals were ventilated by a high frequency jet ventilator. Sneezing and coughing were evoked by mechanical stimulation of the airways. During HFJV spontaneous breathing was inhibited only in the non-vagotomized rabbits. Mechanical stimulation of the airways during HFJV evoked sneezing and coughing, in which the inspiratory component was inhibited. This inhibition occurred not only in defensive reflexes evoked from the regions with increased pressure (trachea, bronchi), but also from the nose. Vagotomy diminished but did not fully eliminate the changes in sneezing accompanying HFJV. The intensity of maximum expiratory efforts was not significantly affected by HFJV in both subgroups.

Animals↗

PubMed1994

[The pulmonary surfactant factor. Current knowledge, research trends and use in clinical practice].

Investigation of the composition and significance of individual components of the surfactant indicated that besides phospholipids an important role is played also by surfactant proteins. They aid not only the reduction of the surface tension of the lungs (SP-B, SP-C), but serve also in regulation of surfactant secretion (SP-A) and in local defense and immune responses in the lungs (SP-A and SP-D). Impairments of surfactant were discovered not only in RDS, but also in cases of meconium aspiration, congenital diaphragmatic hernia, pneumonia, pulmonary edema, idiopathic fibrosis of the lungs, alveolar proteinosis, pneumothorax, and bronchial asthma. Therapy by means of exogenous surfactant was proved effective in therapy of RDS. Occasional cases of exogenous surfactant therapy in other pulmonary diseases are auspicious, it is necessary, though, to develop and produce a sufficient amount of exogenous surfactant of high quality and at an acceptable price and to find an optimal manner of surfactant administration into the lungs. A significant perspective is anticipated to utilization of intrapulmonary administration of the exogenous surfactant as a carrier of further active substances for local administration into the lungs. (Ref. 36.)

Pulmonary Surfactants↗