Biomedical subjects

P Novak

Publications and source records attributed to P Novak.

At least 37 records · Page 2Linked to original sources

PubMed1999

Complications in the first year of laparoscopic gastric banding: is it acceptable?

BACKGROUND: From December 1997 to December 1998, 25 laparoscopic adjustable silicone gastric banding (LASGB) procedures were done without previous experience in bariatric surgery. Body mass index (BMI) ranged from 37 to 57 kg/m2 (average 45.5 kg/m2). METHODS: Retrospective analysis of the 1-year experience was done. Operating time was measured, and BMI and complications were reviewed. RESULTS: Five complications were observed. There was a complication rate of 20%. On two occasions, it was gastric wall slippage, and both were corrected laparoscopically. In one patient, the intususception of the gastric wall through the band resulted after profuse vomiting. Removal of the band was necessary, with conversion to an open procedure. On two occasions, the infection of the port-site was observed, in one of these patients, port removal was necessary. No antibiotic prophylaxis was used. CONCLUSION: Despite lack of experience in bariatric surgery in these laparoscopic surgeons, the complications with LASGB appear to be acceptable. Although prior bariatric surgical experience is preferable.

Adult↗

PubMed1999

[Attitudes and health status as determinants of participation in individually oriented health promotion].

In a cross-sectional health survey among employees of a large German metal company with 974 study participants, attitudes and aspects of the individual health status were identified which predispose employees to take part in individual health promotion activities. Apart from higher participation rates in women and white collar employees, participants reported on average a less favourable subjective health status, more complaints and diseases, better health related behaviours, and a more intensive utilization of curative and preventive medical services than nonparticipants. Among men, participation in all types of courses increased from the youngest to the oldest group, among women only until the middle-aged groups with a consequent decline thereafter. In men, the image of a person living health-consciously showed the strongest positive association with participation, and not the degree of internal control and responsibility with respect to the maintenance of health or the acquisition and overcoming of disease. The low participation of blue collar workers compared to white collar employees could be attributed to group specific differences in individual health consciousness only to a very small extent. Blue collar participants reported a positive image of a person living health-consciously that was more similar to that of white collar participants than to that of nonparticipants of their own occupational group. Advertisement for health promoting activities should place more emphasis on increasing the image of personal health promotion than on internal control and responsibility for health.

Adult↗

PubMed1999

[Laparoscopic appendectomy in acute appendicitis].

Laparoscopic appendectomy has not yet become a stable part of surgical armamentary as has laparoscopic cholecystectomy. The authors on the basis of their own experience show its benefit for the surgeon and for the patient. The conversion rate (7.7%) in the study group is comparable with literature data. The indication for operation was always periappendical mass, in combination with retroceocal position of the appendix. Minimum complication rate in the study group (one case of subfebrile fever in 5 days), very good overview in operation field with the possibility to treat also another pathologic findings concern the authors together with short hospital stay a clear advantages of laparoscopic appendectomy. On the basis of this experience their advocate the routine use of this operation. (Ref. 19.)

Acute Disease↗

PubMed1998

[Eating habits of employees in the metal industry: determinants and patterns].

We conducted a survey on chances and barriers of occupational health promotion and health behaviour including diet in two South German metal companies. Only a small percentage of the 1641 participants consumed healthy food each day, but many avoided eating unhealthy food. Most employees are characterized by a combination of healthy and unhealthy elements. The group of "healthy eaters" consists of more women than men, more older than younger people and more non-manual than manual workers. The level of education and number of children have not been associated with eating habits. Healthy eaters consumed less alcohol and tobacco and were more engaged in sports and in health promotion programmes than unhealthy eaters.

Age Factors↗

PubMed1998

[Manifestation of Wegener's granulomatosis as lacrimal sac tumor].

HISTORY AND SIGNS: This is a report on a patient, who presented an ulcerated lesion (1.5 x 1.2 cm) in the lacrimal sac area. The lesion had existed for 3 months before the patient went to an ophthalmologist. The lacrimal pathway was rinsable all the time. THERAPY AND OUTCOME: The patient was treated by antibiotics and leukase cones at first. But the lesion showed no tendency to heal under this therapy. The patient was sent to the ETN department for further investigations. At this time the suspicion of a malignant process was discussed. In the meantime the lesion became epithelialized, but no closure could be reached at any time. The CT scans showed a bone defect of 1 cm of the lamina papyracea. Tumorous tissue passed through this defect reaching the ulcer at the medial canthal angle. A biopsy was been taken and revealed granulomatous tissue typical for a Wegener's granulomatosis. The patient was sent to an Internal medicine department, but he died one month later due to systemic disorders of this disease. CONCLUSIONS: Although an acute dacryocystitis is most often the reason for a lacrimal sac swelling and inflammation, in all cases of rinsable lacrimal pathway and long term lacrimal sac ectasy a neoplastic or a granulomatous reason has to be excluded.

Biopsy↗

PubMed1998

Autoregulation of cerebral blood flow in orthostatic hypotension.

BACKGROUND AND PURPOSE: We sought to evaluate cerebral autoregulation in patients with orthostatic hypotension (OH). METHODS: We studied 21 patients (aged 52 to 78 years) with neurogenic OH during 80 degrees head-up tilt. Blood flow velocities (BFV) from the middle cerebral artery were continuously monitored with transcranial Doppler sonography, as were heart rate, blood pressure (BP), cardiac output, stroke volume, CO2, total peripheral resistance, and cerebrovascular resistance. RESULTS: All OH patients had lower BP (P<.0001), BFV_diastolic (P<.05), CVR (P<.007), and TPR (P<.02) during head-up tilt than control subjects. In control subjects, no correlations between BFV and BP were found during head-up tilt, suggesting normal autoregulation. OH patients could be separated into those with normal or expanded autoregulation (OH_NA; n=16) and those with autoregulatory failure (OH_AF; n=5). The OH_NA group showed either no correlation between BFV and BP (n=8) or had a positive BFV/BP correlation (R2>.75) but with a flat slope. An expansion of the "autoregulated" range was seen in some patients. The OH_AF group was characterized by a profound fall in BFV in response to a small reduction in BP (mean deltaBP <40 mm Hg; R2>.75). CONCLUSIONS: The most common patterns of cerebral response to OH are autoregulatory failure with a flat flow-pressure relationship or intact autoregulation with an expanded autoregulated range. The least common pattern is autoregulatory failure with a steep flow-pressure relationship. Patients with patterns 1 and 2 have an enhanced capacity to cope with OH, while those with pattern 3 have reduced capacity.

Aged↗

PubMed1998

Hypocapnia and cerebral hypoperfusion in orthostatic intolerance.

BACKGROUND AND PURPOSE: Orthostatic and other stresses trigger tachycardia associated with symptoms of tremulousness, shortness of breath, dizziness, blurred vision, and, often, syncope. It has been suggested that paradoxical cerebral vasoconstriction during head-up tilt might be present in patients with orthostatic intolerance. We chose to study middle cerebral artery (MCA) blood flow velocity (BFV) and cerebral vasoregulation during tilt in patients with orthostatic intolerance (OI). METHODS: Beat-to-beat BFV from the MCA, heart rate, CO2, blood pressure (BP), and respiration were measured in 30 patients with OI (25 women and 5 men; age range, 21 to 44 years; mean age, 31.3+/-1.2 years) and 17 control subjects (13 women and 4 men; age range, 20 to 41 years; mean age, 30+/-1.6 years); ages were not statistically different. These indices were monitored during supine rest and head-up tilt (HUT). We compared spontaneous breathing and hyperventilation and evaluated the effect of CO2 rebreathing in these 2 positions. RESULTS: The OI group had higher supine heart rates (P<0.001) and cardiac outputs (P<0.01) than the control group. In response to HUT, OI patients underwent a greater heart rate increment (P<0.001) and greater reductions in pulse pressure (P<0.01) and CO2 (P<0.001), but total systemic resistance failed to show an increment. Among the cerebrovascular indices, all BFVs (systolic, diastolic, and mean) decreased significantly more, and cerebrovascular resistance (CVR) was increased in OI patients (P<0.01) compared with control subjects. In both groups, hyperventilation induced mild tachycardia (P<0.001), a significant reduction of BFV, and a significant increase of CVR associated with a fall in CO2. Hyperventilation during HUT reproduced hypocapnia, BFV reduction, and tachycardia and worsened symptoms of OI; these symptoms and indices were improved within 2 minutes of CO2 rebreathing. The relationships between CO2 and BFV and heart rate were well described by linear regressions, and the slope was not different between control subjects and patients with OI. CONCLUSIONS: Cerebral vasoconstriction occurs in OI during orthostasis, which is primarily due to hyperventilation, causing significant hypocapnia. Hypocapnia and symptoms of orthostatic hypertension are reversible by CO2 rebreathing.

Adult↗

PubMed1998

Clinical and laboratory indices that enhance the diagnosis of postural tachycardia syndrome.

OBJECTIVE: To identify clinical and laboratory indices that improve the diagnosis of the postural tachycardia syndrome (POTS). DESIGN: We assessed associations of orthostatic intolerance by using multivariate regression analysis. MATERIAL AND METHODS: We evaluated autonomic symptoms and autonomic function in 30 patients with POTS, 30 patients with mild orthostatic intolerance, and 19 age- and gender-matched control subjects. Indices of parasympathetic and sympathetic functions were analyzed on the basis of (1) autonomic function tests (head-up tilt), (2) oscillations at respiratory and nonrespiratory frequencies (0.01 to 0.09 Hz) in R-R interval and blood pressure (Wigner distribution), and (3) deterministic component (rescaled range analysis). RESULTS: The four clinical and laboratory indices that independently supported the diagnosis of POTS are as follows: (1) orthostatic heart rate during the first minute of head-up tilt, (2) autonomic deficit (adrenergic autonomic score), (3) loss of spectral powers in R-R interval during head-up tilt at the fifth minute, and (4) severity of orthostatic dizziness, fatigue, palpitations, and shortness of breath. CONCLUSION: Enhancing the sensitivity and specificity of the diagnosis of POTS should be possible by using these four indices. A hyperadrenergic state and distal neuropathy, affecting adrenergic sympathetic cardiovagal fibers, seem to be involved in the pathophysiology of POTS. Certain features suggest brain-stem dysregulation.

Adult↗

PubMed1998

[Need adjustment of utilization of occupational health promotion for reducing back pain? Results of an employee survey of the metal industry].

We analysed data of a cross-sectional survey of 974 employees in the German metal industry to determine the degree to which worksite health promotion matches the needs of employees. 27% of study participants have already taken part in individually oriented health promotion, and another 48% want to participate most readily in activities aiming at preventing and reducing musculo-skeletal complaints. Recent participation (within a fourteen-month period) in these classes was low among male blue collar workers (7%) compared to male and female white collar employees (18 and 26%). Among blue collar workers the percentage of subjects who suffered from chronic back pain and did not recently participate in the relevant classes of the company health insurance plan (unserved prevalence) was 30%, compared to 17 and 26% in male and female white collar employees. Participants were less exposed to work-related predictors of chronic back pain than non-participants. Participants were, however, more often afflicted with chronic back pain than non-participants. In addition, the intention to participate was strongly associated with this type of complaint. Shift work was the most important single explanation for the low participation rates of blue collar workers. Suggestions are advanced to neutralise the adverse effects of shift work on participation, to strengthen the primary preventive functions of individual worksite health promotion, and to integrate it with structural measures of health and safety at work.

Adult↗

PubMed1998

Construction of anthropometric measuring chair (AMC) for lung function prediction.

An anthropometric measuring chair (AMC) was constructed in order to predict lung function parameters (vital capacity--FVC and forced expiratory flow in the first second-FEV1) in normal Caucasian subjects. Design of a chair was aimed toward the fast and reliable recording of body dimensions, particularly of the human thorax. Static and dynamic measurements of thorax dimensions, arm span and sitting height were used to predict FVC and FEV1 with an accuracy better than standard prediction equations based only on body height and age. Computer program for automatic calculation of FVC and FEV1 according to prediction equations was constructed in VisualBasic 4.0 software. The prediction values for FVC and FEV1 based on anthropometric variables could be used in paraplegic, disproportional and handicapped individuals, where standard body height is unobtainable.

Adult↗

PubMed1997

Effect of perturbations and a meal on superior mesenteric artery flow in patients with orthostatic hypotension.

UNLABELLED: Our aims were to evaluate to role of superior mesenteric blood flow in the pathophysiology of orthostatic hypotension in patients with generalized autonomic failure. METHODS: Twelve patients with symptomatic neurogenic orthostatic hypotension and 12 healthy controls underwent superior mesenteric artery flow measurements using Doppler ultrasonography during head-up tilt and tilt plus meal ingestion. Autonomic failure was assessed using standard tests of the function of the sympathetic adrenergic, cardiovagal and postganglionic sympathetic sudomotor function. RESULTS: Superior mesenteric flow volume and time-averaged velocity were similar in patients and controls at supine rest; however, responses to cold pressor test and upright tilt were attenuated (p < 0.05) in patients compared to controls. Head-up tilt after the meal evoked a profound fall of blood pressure and mesenteric blood flow in the patients; the reduction of mesenteric blood flow correlated (r = 0.89) with the fall of blood pressure in these patients, providing another manifestation of failed baroreflexes. We make the novel finding that the severity of postprandial orthostatic hypotension regressed negatively with the postprandial increase in mesenteric flow in patients with orthostatic hypotension. CONCLUSION: Mesenteric flow is under baroreflex control, which when defective, results in, or worsens orthostatic hypotension. Its large size and baroreflexivity renders it quantitatively important in the maintenance of postural normotension. The effects of orthostatic stress can be significantly attenuated by reducing the splanchnic-mesenteric volume increase in response to food. Evaluation of mesenteric flow in response to eating and head-up tilt provide important information on intra-abdominal sympathetic adrenergic function, and the ability of the patient to cope with orthostatic stress.

Adult↗

PubMed1997

[Recent developments in lacrimal duct endoscopy].

BACKGROUND: At the moment digital dacryocystography yields the most exact results in lacrimal diagnostics. The main disadvantage lies in the dependency of high tech X-ray systems and an angiography unit, which raise enormously the costs of the examination. Recently a new diagnostic system of the lacrimal pathway is available. PATIENTS AND METHODS: Miniaturizing of endoscopes and new developments in the fiberoptic technology made it possible to introduce these mini-endoscopes into the canaliculi and perform antegrade examination of canaliculi, lacrimal sac and ductus nasolacrimalis. 86 patients agreed to this examination. With this examination a direct visualisation of the mucous membrane of the lacrimal pathways and possible pathological alterations were possible. RESULTS: In case of axial illumination and syringing of the lacrimal system good visibility can be achieved and an exact examination is possible. Especially for endoscopy modified probes of Bangerter provide an exact examination at narrow areas and areas of bendings too. Different reasons for stenosis of the lacrimal pathways could be identified, especially 2 cases of a lacrimal sac tumor. CONCLUSIONS: The use of this new miniendoscope provides a very good examination under direct visualisation of the lacrimal pathway independent of a high tech X-ray equipment. The goal is to use this new endoscope on the one hand only for diagnostic reasons as endoscope and on the other hand in combination with a laser fiber to perform an antegrade laser dacryocystorhinostomy.

Adolescent↗

PubMed1997

[Frontalis suspension with "expanded polytetrafluoroethylene (ePTFE) strips" in congenital ptosis].

BACKGROUND: The Frontalis Suspension Technique is indicated in cases with minimal or no levator function. At the beginning sutures were used as sling material and after further modifications suture material was replaced by autologous or homologous fascia lata. In the last years ePTFE has proved to be a very suitable sling material. PATIENTS AND METHODS: Since ePTFE is very biocompatible, it was used for this modified frontalis suspension technique. The anterior tarsal surface is exposed and a small tunnel is created between the skin incision and the second incision superior to the brow. An 0.3 mm thin ePTFE strip is induced into the tunnel and connects the upper lid with the frontalis muscle. The ePTFE Soft Tissue Patch must be exactly adapted to the tarsus and has to be deeply sutured to the frontalis muscle below the brow incision. Since 1994 17 modified frontalis suspension procedures have been performed on 14 patients. RESULTS: The functional and cosmetic result were good in nearly all patients. No implant had to be removed during the follow up period. DISCUSSION: The new technique of frontalis suspension using a ePTFE strip guarantees a regular upper lid lifting by the axial and direct connection of the anterior tarsal surface with the frontalis muscle.

Blepharoptosis↗

PubMed1996

Postural tachycardia syndrome: time frequency mapping.

Orthostatic tachycardia is common but its specificity remains uncertain. Our preliminary work suggested that using autonomic function testing in conjunction with time-frequency mapping (TFM), it might be possible to characterize a subset of the postural tachycardia syndrome (POTS), that is due to a restricted autonomic neuropathy. We describe 20 patients (17 women and 3 men, aged 14-43 years) with florid POTS and 20 controls (14 women and 6 men, aged 20-41 years). Autonomic failure was quantified by its distribution (cardiovagal, adrenergic and sudomotor) and severity, a symptom profile was generated, and spectral indices, based on modified Wigner distribution during rest and head-up tilt (80 degrees) were evaluated. During tilt-up POTS patients differed from controls by an excessive heart rate (> 130 bpm) (P < 0.001), and higher diastolic pressure (P < 0.01). During rest, cardiovagal oscillations (at respiratory frequencies [RF]) and slow rhythms at nonrespiratory frequencies (NONRF) (from 0.01 to 0.07 Hz) in R-R intervals (RRI) (P < 0.01) were reduced. Both RF and NONRF rhythms in RRI were further blunted with tilt-up (P < 0.001). Slow adrenergic vasomotor rhythms in blood pressure (BP) (approximately 0.07 Hz) surged with tilt-up and returned to normal levels afterwards. The index of sympatho-vagal balance (NONRF-Systolic BP (SBP)/RF-RRI) was dramatically increased in POTS (P < 0.001). Distal postganglionic sudomotor failure was observed, and impairment of the BP responses to the Valsalva maneuver (phase II) suggested peripheral adrenergic dysfunction. Persistent orthostatic dizziness, tiredness, gastrointestinal symptoms and palpitations were common in POTS patients. It is possible to identify a subset of POTS patients who have a length-dependent autonomic neuropathy, affecting the peripheral adrenergic and cardiovagal fibers, with relative preservation of cardiac adrenergic fibers.

Adolescent↗

PubMed1996

Pulsation-pressure relationship in experimental aneurysms: observation of aneurysmal hysteresis.

In this study the pulsation-pressure relationship in an experimental model of aneurysms was analyzed. In addition, we have examined pulsatility of the aneurysmal wall reinforced by Guglielmi Detachable Coils (GDC). Bifurcation (BAn), aneurysms (LAn) and bilobar (BiA) aneurysms were produced in 15 mongrel dogs. The aneurysmal dome was constructed from a segment of the external jugular vein which was sutured to the window performed on the apex of bifurcation of the ECA and lingual artery (BAn) or on the ECA (LAn). One set of the GDC (diameter 5 mm, length 20 cm) were inserted into the aneurysm. Intra-aneurysmal pressure, aneurysmal pulsation, ECG and femoral artery pressure were recorded. Results showed that an experimental aneurysm pulsates in synchrony with the intra-aneurysmal pressure and aneurysmal pulsation is proportional to the aneurysmal size. Pulsation profile also depends on the aneurysmal type (BAn, LAn, BiA). The looped pressure-pulsation curve indicates that aneurysms exhibit property of hysteresis. For the same pressure the aneurysm is smaller during the ascending (systolic) portion of the blood pressure wave. Insertion of catheter into the aneurysm and subsequent release of the GDC did not elicit any measurable changes of the intra-aneurysmal pressure. Aneurysm reinforced by GDC showed smaller pulsation and the hysteresis was reduced as well. It was concluded that aneurysmal hysteresis could be an important factor resulting in degeneration of aneurysmal wall since it is known that hysteresis accelerates degeneration of all fibrous elements, predominantly of elastic fibers. GDC seems to buffer the intra-aneurysmal hemodynamic forces and hence they might have a stabilizing effect on the aneurysmal wall.

Aneurysm↗

PubMed1996

Spontaneous blood pressure fluctuations and renal blood flow dynamics.

Two mechanisms operating at 0.03-0.05 and 0.1-0.2 Hz are involved in autoregulation of renal blood flow (RBF). To examine the behavior of the faster system, the response of RBF to spontaneous fluctuations of arterial pressure was assessed in Sprague-Dawley rats anesthetized by isoflurane or halothane. During halothane anesthesia, autonomous oscillation of total RBF was observed at 0.10-0.15 Hz, and normalized admittance gain became negative at 0.11 +/- 0.01 Hz. During isoflurane anesthesia, there was autonomous power in blood flow in a broad peak between 0.15 and 0.25 Hz, and gain became negative at 0.15 +/- 0.01 Hz. Increasing inspired isoflurane concentration from 1.4 +/- 0.1% to 2.2 +/- 0.1% reduced pressure by 22 +/- 2 mmHg but did not alter blood flow or the transfer function, indicating that the operating frequency was not changed. In another experiment, changing from isoflurane to halothane increased peak power in the autonomous blood flow oscillation fivefold and reduced its frequency from 0.18 +/- 0.01 to 0.14 +/- 0.01 Hz. Gain became negative at a higher frequency (0.16 +/- 0.01 Hz) during isoflurane than halothane anesthesia (0.12 +/- 0.01 Hz). The results show that the 0.1-0.2 Hz system is reliably detected under unforced conditions and provides modest attenuation of pressure fluctuations at < or = 0.1 Hz. Its operating frequency under isoflurane anesthesia is consistent with previous estimates from barbiturate-anesthetized rats, whereas it operates significantly slower under halothane anesthesia.

Administration, Inhalation↗

PubMed1996

Pharmacological modulation of spontaneous renal blood flow dynamics.

Two mechanisms contribute to renal autoregulation. The faster system, which is thought to be myogenic, operates at 0.1-0.2 Hz (i.e., 5-10 s/cycle), while the slower one, tubuloglomerular feedback, operates at 0.03-0.05 Hz (i.e., 20-30 s/cycle). Both attenuate spontaneous or induced fluctuations of blood pressure, but it has proven difficult to separate their individual contributions because there is potential for interaction between the two. The present study was designed to examine the dynamics of the faster system during pharmacological blockade of tubuloglomerular feedback. Normotensive and hypertensive rats were studied under isoflurane or halothane anesthesia. Administration of the loop diuretic furosemide plus the angiotensin II (ANGII) AT1 receptor antagonist losartan caused a 10-fold or greater natriuresis, indicating profound inhibition of ascending limb salt transport, and also produced characteristic changes in the transfer function relating blood pressure (input) to renal blood flow (output). Operation of the 0.1-0.2 Hz mechanism was essentially unaltered, as shown by the presence of a peak in phase angle at 0.1-0.2 Hz and reduction of gain at frequencies slower than 0.15 Hz. The 0.03-0.05 Hz mechanism was markedly inhibited, as shown by loss of the second phase angle peak at 0.03-0.05 Hz, loss of the local maximum in gain at 0.05 Hz, and loss of the second gain reduction below 0.05 Hz. Both during control and after inhibition of tubuloglomerular feedback, the 0.1-0.2 Hz system attenuated = 50% of the effects of spontaneous blood pressure fluctuations, suggesting that this mechanism, operating alone, can significantly stabilize renal blood flow in the face of spontaneous fluctuations of blood pressure.

Anesthetics, Inhalation↗

PubMed1995

The effect of severe brainstem injury on heart rate and blood pressure oscillations.

To determine whether an intact brainstem is essential for the generation of neurogenically mediated fluctuations of R-R intervals and blood pressure, three patients with cerebellar lesions causing severe brainstem compression or death, one patient with a large pontine infarct and one patient with a pontine haemorrhage, were studied. Time-frequency maps (based on a modified Wigner distribution) were constructed from blood pressure and R-R interval signals in these patients with brainstem injury and were compared with maps of normal control subjects. Low frequency sympathetically mediated rhythms (0.01-0.12 Hz) in systolic and diastolic pressure remained detectable but attenuated in patients with brainstem injury whereas there was an almost complete loss of normal R-R intervals rhythmicity over 0.01 to 0.5 Hz range. These data suggest that fluctuations in R-R intervals require an intact brainstem, whereas low frequency approximately 0.06 +/- 0.02 Hz blood pressure rhythms may be preserved by spinal sympathetic circuitry.

Aged↗