Search PubMed⌕ Search

Biomedical subjects

A Lindner

Publications and source records attributed to A Lindner.

At least 19 recordsLinked to original sources
PubMed2006

[Headache after a stay in the Dominican Republic].

CASE HISTORY: In a 27-year-old female German patient severe headache and wandering paresthesias appeared one week after returning from a holiday in the Dominican Republic. After 3 weeks of ongoing symptoms she was admitted to our hospital with the suspicion of an inflammatory or infectious disease of the central nervous system. Upon admission slight stiffness of the neck, fever (38.2 C) and paresthesias of the right elbow and the right thigh were noticed. LABORATORY FINDINGS: Cerebrospinal fluid (CSF) revealed an eosinophilic pleocytosis. In the acute phase of the disease, antibodies against nematodes were found in CSF, without corresponding antibody-reactivity in serum. In the course levels of nematode antibodies in CSF increased and antibody-reactivity in serum was observed. Thorough investigation for other infectious or inflammatory causes of eosinophilic meningitis revealed no abnormalities. DIAGNOSIS, TREATMENT AND COURSE: Symptoms, onset within the typical incubation period and the eosinophilic meningitis lead to the diagnosis of a suspected Angiostrongyliasis. Successful treatment was achieved with a combination of oral albendazole and corticosteroids given for 4 weeks. CONCLUSION: Infection with larvae of Angiostrongylus cantonensis is one of the main causes of eosinophilic meningitis worldwide. Human infection can occur after ingestion of intermediate hosts or contaminated vegetables. Angiostrongyliasis has been endemic to Southeast Asia and the Pacific Basin and only recently cases from the Caribbean have been described. Headache, paresthesias and the finding of an eosinophilic meningitis in patients returning from tropical or subtropical regions should lead to the suspicion and eventually the treatment of an Angiostrongyliasis.

Adult↗
PubMed2005

[Sudden hearing loss as the leading symptom of an infarction of the left anterior inferior cerebellar artery].

The sudden onset of hearing impairment or hearing loss can be a characteristic sign of a vertebrobasilar circulatory disturbance. We report on a 65 year old male patient with an acute left-sided tinnitus followed by hearing loss as an initial symptom of an infarction of the left anterior inferior cerebellar artery (AICA). Successively, additional symptoms with vertigo, nausea, vomiting and a transient dysarthria and ataxia of the left upper extremity occurred. In the course of the illness, the hearing loss, ataxia and dysarthria completely recovered. MRI of the brain showed an infarction in the area of the anterior inferior cerebellar artery; neurosonographic examination of the basilar and vertebral arteries was normal. Therefore, in patients with acute hearing impairment or hearing loss, an AICA-ischemia should be considered and the patient carefully examined for additional brainstem symptoms, since this can be the first sign of an life-threatening basilar artery thrombosis.

Aged↗
PubMed2004

Subcritical failure of soft acrylic adhesives under tensile stress.

The mechanisms of failure over time of a series of model acrylic pressure-sensitive adhesives under a moderate level of stress has been investigated with a probe method. Two competing mechanisms of failure have been observed: a progressive nucleation of cavities under stress and the propagation of existing cavities at the interface between the probe and the adhesive layer. Homogeneous creep of the adhesive was never observed as the only failure mechanism. In situations where the resistance to crack propagation was good relative to the resistance to cavitation, extensive nucleation of cavities was observed until a material-dependent and stable value of stress was achieved. On the other hand in situations were the resistance to crack propagation was weak, propagation led invariably to a complete failure of the adhesive bond. In addition to the stress relaxation, the energy dissipation was studied allowing to distinguish the different adhesives even further. This allowed determination of the optimal amount of a comonomer (acrylic acid) that had to be added to improve the long-term resistance of the adhesives under study. Further more we investigate the compliance of the confined adhesive layers and compare the obtained results to predictions from theoretical models.

Acrylates↗
PubMed2003

[Rhabdomyolysis and myoglobinuria].

Rhabdomyolysis is a disorder characterized by acute damage of the sarcolemma of the skeletal muscle leading to release of potentially toxic muscle cell components into the circulation, most notably creatine phosphokinase (CK) and myoglobin, and is frequently accompanied by myoglobinuria. Therefore, the term myoglobinuria is often used interchangeably with the term rhabdomyolysis. This disorder may result in potential life-threatening complications such as acute myoglobinuric renal failure, hyperkalemia and cardiac arrest, disseminated intravascular coagulation, and compartment syndrome. The condition is etiologically heterogeneous and may result from a large variety of diseases affecting muscle membranes, membrane ion channels, and muscle energy supply including acquired causes (e.g., exertion, crush injury and trauma, alcoholism, drugs, and toxins) and hereditary causes (e.g., disorders of carbohydrate metabolism, disorders of lipid metabolism, or diseases of the muscle associated with malignant hyperthermia). In many patients with idiopathic recurrent rhabdomyolysis, specific inherited metabolic defects have not been recognized up to now.

AMP Deaminase↗
PubMed2003

[Acute headache with meningism and xanthochromic cerebrospinal fluid.An unusual manifestation of cervical epidural abscess].

We report on a 70-year-old female with acute onset of headache, meningism, xanthochromic cerebrospinal fluid, and developing laboratory parameters indicating a systemic infection. Initially, a subarachnoidal hemorrhage was assumed. However, magnetic resonance imaging showed upper cervical osteomyelitis and extending spinal epidural abscess. After application of broad systemic antibiotics, secluded abscess formation was achieved and successful neurosurgical debridement performed. The unusual cranial concentration of the complaints is probably due to the involvement of the craniocervical transition. Cervical epidural spinal abscess represents a potentially dangerous bacterial infection of the upper spine. Inadequate treatment can lead to irreversible neurological deficits. Cervical magnetic resonance imaging is an effective tool for diagnosis, since early diagnosis is important for good prognosis.

Aged↗
PubMed2003

[Age dependence of Doppler parameters in the basal cerebral arteries evaluated by transcranial color-coded duplex sonography. Reference data from 290 volunteers].

AIM: In this study the Doppler parameters of the basal intracranial arteries and the insonation in axial and coronary plane by temporal approach were established in healthy volunteers of all age groups with transcranial color-coded duplex sonography (TCDS). METHODS: 290 healthy probands (age 0 to 91 years) were investigated through the temporal and transnuchal ultrasound window. The angle corrected flow velocities and the resistance indices of the basal brain arteries were measured. RESULTS: The flow velocities rapidly increase in children (from 3 years up to puberty) and gradually decrease with increased age. Vice versa, the resistance indices decrease in children and increase in older people. The flow velocities show significant differences by axial and coronary insonation in certain arteries of the circle of Willis. CONCLUSION: The Doppler parameters of the basal intracranial arteries evaluated with TCDS depend from age. The flow velocities and resistance indices are similar in children and older people. The coronary transtemporal approach is considered a useful completion of the axial investigation.

Adolescent↗
PubMed2002

Brainstem infarctions with normal MRI.

Most studies on brainstem infarctions included only patients with lesions documented by CT or MRI. The aim of this study was to analyse the clinical symptomatology in patients with the classical signs of brainstem infarcts and normal MRI results. Frequencies of MR-positive and negative infarctions should be analysed according to their location. In a series of 30 consecutive patients with acute clinical symptoms of ischemic brainstem lesions and persistence of the symptomatology for more than 10 days, 8 patients had normal MRI. In these patients the location of the lesion was established by clinical and electrophysiological criteria. The lesions in the 8 patients with normal MRI were situated in medulla oblongata (n=3), in pons (n = 2), and in midbrain (n = 3). In each of these patients the clinical symptoms corresponded to one of the classical alternating syndromes, which are pathognomic for brainstem infarctions (1 Wallenberg, 1 Avellis, 1 Jackson, 2 Millard-Gubler, and 3 Weber). The clinical course of the infarctions with normal MRI was favourable, the symptoms disappeared within few weeks. Our study proved that the clinical diagnosis of brainstem infarction, particularly in lesions of midbrain and caudal tegmentum pontis, can not be excluded by normal MRI.

Aged↗
PubMed2002

Effects of repeated biopsying on muscle tissue in horses.

The collection of muscle samples in horses to estimate their performance potential, adaptations to training and diagnosis of exertional myopathies is of increasing interest. This study was designed to examine whether repeated biopsying of the gluteus medius muscle at 7 week intervals alters morphology and muscle fibre variables in the sampling area. The gluteus had been biopsied 3 times previously, each biopsy separated by a 7 week interval. Seven weeks after the last biopsy, this study was initiated. Percutaneous needle biopsies were taken from left and right muscles at 2 depths (2 and 6 cm) and at 2 sites for each depth (22 and 25 cm from the tuber coxae) of 7 mature Thoroughbreds. The 22 cm site was located close (2 cm caudal) to an area of the muscle that had been biopsied previously. The 25 cm site was 5 cm apart from this area. A total of 52 samples were available for histology, electron microscopy and immunohistochemistry. The latter was used to study percentages, sizes and capillaries of muscle fibre types. Most muscle samples collected (75%) had normal morphology, but the remaining 25% showed signs of muscle repair. In some circumstances, they showed regenerative signs of complete muscle repair, while in others ineffective muscle repair (scar formation) was evident. Nevertheless, sufficient normal tissue was always available for measuring routine muscle variables. Samples collected 3 cm laterally apart showed large differences with regard to muscle fibre type variables examined. These results show that repeated muscle samples in intervals of 7 weeks do not have effects that would impair evaluation of muscle fibre variables for diagnosis of effectivity of conditioning programmes. Furthermore, they emphasise that the only way of keeping variations through sample collection technique small is to standardise all biopsying techniques accurately.

Animals↗
PubMed2001

Optimizing visual motion perception during eye movements.

We usually perceive a stationary, stable world and we are able to correctly estimate the direction of heading from optic flow despite coherent visual motion induced by eye movements. This astonishing example of perceptual invariance results from a comparison of visual information with internal reference signals predicting the visual consequences of an eye movement. Here we demonstrate that the reference signal predicting the consequences of smooth-pursuit eye movements is continuously calibrated on the basis of direction-selective interactions between the pursuit motor command and the rotational flow induced by the eye movement, thereby minimizing imperfections of the reference signal and guaranteeing an ecologically optimal interpretation of visual motion.

Chi-Square Distribution↗
PubMed2001

Cortical substrates of perceptual stability during eye movements.

We are usually unaware of retinal image motion resulting from our own movement. For instance, during slow-tracking eye movements, the world around us remains perceptually stable despite the retinal image slip induced by the eye movement. This example of perceptual invariance is achieved by subtracting an internal reference signal, reflecting the eye movement, from the retinal motion signal. If the two cancel each other, visual structures, which do not move, will also be perceived as nonmoving. If, however, the reference signal is too small or too large, a false eye-movement-induced motion of the external world will be perceived. We have exploited our ability to manipulate the size of the reference signal in an attempt to reveal the structures in visual cortex, encoding the perception of self-induced visual motion rather than the retinal motion signal. Using EEG and lately also MEG recordings in human subjects and single-unit recordings in monkeys, we have been able to show that our ability to perceive the world as stationary despite eye-movement-induced retinal image slip is based on "late" parts of the cortical hierarchy of motion processing, sparing the early stages up to cortical area MT and, among others, involving cortex at the junction between the parietal and temporal lobes close to the parieto-insular-vestibular cortex. Lesions of this network in humans render the visual system unable to compensate for the visual consequences of eye movements, giving rise to severe dizziness, whenever the eyes move smoothly.

Animals↗
PubMed2001

Cancellation of self-induced retinal image motion during smooth pursuit eye movements.

When our eyes are tracking a target that is moving in front of a structured background, global motion of equal speed is induced in the opposite direction. This effect has been termed reafference, which, astonishingly, does not significantly affect the execution of such pursuit eye movements. Employing brief and unexpected injections of full-field motion during ongoing human smooth pursuit, we demonstrate that the sensitivity for full-field motion is reduced strongly in the direction opposite to the eye movement, i.e. the direction of reafferent background motion. Our experiments further characterize this asymmetry in visual motion processing and provide a preliminary explanation for the accuracy of the pursuit system despite self-induced motion.

Adult↗
PubMed2001

[Correlation of clinical and magnetic resonance imaging findings in patients with brainstem infarction].

The aim of this study was the comparison of clinical and neurological findings in 30 patients presenting with ischemic brainstem lesions. These were localized in the midbrain in 4 cases, in the medulla in 12 cases and in the pons in 11 cases, while the remaining three patients demonstrated combined lesions. Symptoms were lesions of the pyramidal tract in 77% of cases, vertigo in 57% of cases, speech disturbances in 40% of cases and gait ataxia in 37% of cases. Cranial nerve lesions were evident in 87% of patients, while 33% of patients demonstrated a Horner syndrome. Brainstem lesions were diagnosed in 22 (73%) of patients on magnetic resonance imaging, while all 30 patients had clinical signs suggestive of brainstem lesions. We conclude that neuroradiological studies can provide helpful information regarding patients with brainstem lesions, but by no means replace exact neurological examination.

Adult↗
PubMed2001

Factors affecting tube dwelling time after percutaneous nephrolithotomy.

BACKGROUND AND PURPOSE: Little is known about the impact of nephrostomy tubes on morbidity and quality of life. PATIENTS AND METHODS: The tube dwelling time and the factors influencing it were determined in 165 patients undergoing percutaneous nephrolithotomy (PCNL). RESULTS: The mean tube dwelling time was 21+/-30 days. The duration of tube drainage after PCNL was 13+/-17 days. Most of this time was preoperative when the tube was inserted for urgent reasons--obstruction or sepsis (31+/-33 days). On multivariate analysis, the number of secondary PCNLs and postoperative complications were the most significant factors affecting tube dwelling time. Age correlated with intubation time but did not reach statistical significance (P < 0.09). Neither the stone's side and type nor the patient's sex had a significant influence. CONCLUSIONS: A significant factor affecting the duration of tube drainage is preoperative medical evaluation and patient preparation, and these steps should be completed expeditiously in order to minimize the time to PCNL. Completion of PCNL in one session should shorten the postoperative intubation time.

Adult↗