Biomedical subjects

N Mayr

Publications and source records attributed to N Mayr.

At least 19 recordsLinked to original sources

PubMed2000

[Edrophonium chloride (Tensilon) test: a safe method in diagnosing myasthenia gravis].

OBJECTIVE: To evaluate the safety of edrophonium chloride in the course of the Tensilon test by measurement of hemodynamic and ECG parameters and the observation of adverse events. METHODS: 25 patients with known or suspected myasthenia gravis were included in an open, prospective study concerning the performance of the Tensilon test. Blood pressure, heart rate, continuous ECG and adverse events were recorded 10 minutes following intravenous application of Tensilon. RESULTS: Blood pressure and heart rate did not change significantly during the observation period. One patient on beta-blockers developed a grade I AV block. Self-limiting adverse events of short duration were observed in 11 patients. Serious adverse events such as syncope or hemodynamic deterioration did not occur. CONCLUSION: The Tensilon test appears to be a safe procedure. A detailed clinical cardiac history, the history of medication and twelve lead ECG recordings should be documented in all patients undergoing the Tensilon test. Patients with a history of dysrhythmia receiving digitalis, beta-blocking agents or Ca antagonist therapy should be managed with special care, as Tensilon enhances vagal effects.

Adult↗

PubMed2000

Cervical cancer diagnosed shortly after pregnancy: prognostic variables and delivery routes.

OBJECTIVE: To compare the prognoses of women diagnosed with cervical cancer during pregnancy with the prognoses of those diagnosed within 6 months after delivery and to assess the effect of vaginal delivery on recurrence risk and prognosis. METHODS: A matched case-control study of women with cervical cancer diagnosed during pregnancy or within 6 months of delivery was performed. Fifty-six women had cervical cancer diagnosed during pregnancy and 27 within 6 months after delivery. Controls (cervical cancer diagnosed at least 5 years since last delivery) were matched one-to-one with cases based on age, histology, stage, treatment, and time of treatment. RESULTS: Among postpartum women, four had stage IA disease, 15 had stage IB1 or IB2, and eight had stage IIA or higher disease. Eleven had radical hysterectomies and 14 had radiation therapy. Two with stage IA1 disease were treated with vaginal hysterectomies. One of seven patients who had cesareans developed a local and distant recurrence. In contrast, ten of 17 (59%) who delivered vaginally developed recurrences (P =.04). In multivariate analysis, vaginal delivery was the most significant predictor of recurrence (odds ratio [OR] 6.91; 95% confidence interval [CI] 1.45, 32.8), followed by high stage (OR 4.66; 95% CI 1.05, 20.8). The survival for patients diagnosed in the postpartum period was significantly worse than for controls. CONCLUSION: Women diagnosed postpartum had worse survival than those diagnosed during pregnancy and were at significant risk of recurrent disease, particularly if they delivered vaginally. Therefore, pregnant women with cervical cancer should be delivered by cesarean.

Adenocarcinoma↗

PubMed2000

Clinical significance of autoimmune thyroid disease in myasthenia gravis.

We investigated thyroid function and autoimmunity in 74 (61% females) consecutive patients with MG. 30 of these patients were tested twice: the time between the investigations ranging from 1 to 4 years. MG was diagnosed on the basis of typical clinical symptoms, a positive tensilone-test, and/or detectable acetylcholine antibodies and/or repetetive stimulation tests. Eye involvement was present in 86%, concurrent thymomas in 56%. The following parameters were measured in the serum of these patients by commercially available kits: free and total T4, TSH, TSH-Receptor-Antibodies ("TRAB"), antibodies against thyroglobulin (Tg-Ab), against thyroid microsomes (M-Ab) and against acetyl-choline-receptors . An age matched group of 50 patients (54% females) with no known thyroid disease from a cardiological ward and from the neurological outpatient department served as control. There was only 1 MG patient with overt thyroid dysfunction (iodine induced thyrotoxicosis in a patient with autonomous adenoma and no circulating thyroid autoantibodies detected at the second investigation). There were, moreover, 1 euthyroid MG-patient on L-thyroxine therapy with a history of Hashimoto's disease and positive thyroid autoantibodies and 1 other MG-patient with mildly elevated TSH without elevated thyroid antibodies, who has had subtotal thyroidectomy without substitution therapy years before for unknown reasons. Tg-Ab were positive (>360 IU/ml) in 5%, M-Ab were positive (>154 IU/ml) in 15% of the MG patients. The control group had 4% Tg-Ab and 6% M-Ab. TRAB levels were normal in all patients and controls. The relative increase in M-Ab frequency was not statistically significant (x-square test). We conclude from our results, that autoimmune thyroid disease may be associated with MG but that the occurrence of thyroid dysfunction induced by autoimmunity is a very rare phenomenon in MG.

Adolescent↗

PubMed1999

MR imaging of tumor microcirculation: promise for the new millennium.

Dynamic contrast-enhanced magnetic resonance imaging (DCE MRI) is a method of imaging the physiology of the microcirculation. A series of recent clinical studies have shown that DCE MRI can measure and predict tumor response to therapy. Recent advances in MR technology provide the enhanced spatial and temporal resolution that allow the application of this methodology in the management of cancer patients. The September issue of this journal provided a microcirculation section to update readers on this exciting and challenging topic. Evidence is mounting that DCE MRI-based measures correlate well with tumor angiogenesis. DCE MRI has already been shown in several types of tumors to correlate well with traditional outcome measures, such as histopathologic studies, and with survival. These new measures are sensitive to tumor physiology and to the pharmacokinetics of the contrast agent in individual tumors. Moreover, they can present anatomical images of tumor microcirculation at excellent spatial resolution. Several issues have emerged from recent international workshops that must be addressed to move this methodology into routine clinical practice. First, is complex modeling of DCE MRI really necessary to answer clinical questions reliably? Clinical research has shown that, for tumors such as bone sarcomas, reliable outcome measures of tumor response to chemotherapy can be extracted from DCE MRI by methods ranging from simple measures of enhancement to pharmacokinetic models. However, the use of similar methods to answer a different question-the differentiation of malignant from benign breast tumors-has yielded contradictory results. Thus, no simple, one-size-fits-all-tumors solution has yet been identified. Second, what is the most rational and reliable data collection procedure for the DCE MRI evaluation? Several groups have addressed population variations in some key variables, such as tumor T(1)0 (T(1) prior to contrast administration) and the arterial input function C(a)(t) for contrast agent, and how they influence the precision and accuracy of DCE MRI outcomes. However, despite these potential complications, clinical studies in this section show that some tumor types can be assessed by relatively simple dynamic measures and analyses. The clinical scenario and tumor type may well determine the required complexity of the DCE MRI exam procedure and its analysis. Finally, we suggest that a consensus on naming conventions (nomenclature) is needed to facilitate comparison and analysis of the results of studies conducted at different centers. J. Magn. Reson. Imaging 10:903-907, 1999.

Arteries↗

PubMed1999

Neurological function during long-term therapy with recombinant interferon alpha.

In 14 patients with myeloproliferative disorders associated with thrombocytosis, neurological and neuropsychological function were monitored prior to therapy with recombinant human interferon alpha (rIFN; dose 25 mU/week; range 10-35 mU/week) and after 3, 6, 9, and 12 months of treatment. No overt neurological side effects were observed except 1 case of cerebral insult, probably not treatment-related. Attention, memory function, and tapping improved significantly. The P2-N3 amplitudes of visually evoked potentials increased during normalization of platelet counts. Muscular strength and the amplitude of the compound muscle action potential of the median and peroneal nerves increased significantly in an inversely dose-related fashion. In patients with myeloproliferative disorders, long-term therapy with low to intermediate doses of rIFN does not seem to impair neurological function, but rather is associated with enhanced muscle power and the level of mental arousal.

Aged↗

PubMed1998

Leprosy affects facial nerves at the main trunk: neurolysis can possibly avoid transfer procedures.

The predilective sites of lesions in leprous peripheral nerves are well established, and their surgical decompression is common practice when sensorimotor disorders persist after medication. By contrast, the precise localization of leprous facial neuropathy still remains unclear, and musculofascial transfers have been the only type of surgical treatment. The goal of this study was to clarify where leprosy affects facial nerves and to determine whether neurolysis might suffice to restore facial function. In five Indian and two Egyptian patients suffering from leprous facial neuritis, the nerves were stimulated transcranially at the brainstem to evoke efferent motor nerve action potentials, which were recorded from the exposed nerves. Lesions were detected at the main trunk proximally from the first bifurcation in all cases. Epineuriotomy revealed fibrosis of the interfascicular epineurium in all instances, as an indication for interfascicular neurolysis. One patient was able to close his eye and showed a better smile soon after surgery. After 16 and 21 months, respectively, one patient had improved distinctly, two patients slightly, two patients showing no progress, and two patients were lost to follow-up. It is concluded that (1) leprous facial neuropathy is located at the main trunk close to the first bifurcation and not exclusively at the peripheral zygomatic branches, (2) microsurgical neurolysis can be considered in leprous facial neuropathy before transfer procedures as long as voluntary or spontaneous activity is present in the affected muscles, and (3) intraoperative transcranial electrical stimulation is an effective means of localizing the site and proximal extent of leprous facial neuropathy.

Adult↗

PubMed1997

Radiotherapeutic management of cervical carcinoma that complicates pregnancy.

BACKGROUND: Data regarding radiation therapy for pregnant patients with cervical carcinoma are limited. The goal of this study was to assess the effects of pregnancy on tumor control, survival, and morbidity associated with radiation therapy administered to pregnant patients. METHODS: The authors performed a retrospective case-control analysis of 26 women with cervical carcinoma who were diagnosed during pregnancy and treated primarily with radiation therapy. These cases were matched with 26 controls based on age, histology, stage, treatment, and year of treatment. RESULTS: Patients were treated with external beam radiation (mean dose, 46.7 gray [Gy]) and intracavitary radiation (mean dose, 56.5 Gy to Point A). Two patients with Stage IA2 squamous cell carcinoma treated in the third trimester had a planned delay in treatment of 3 weeks, and both infants had an uncomplicated neonatal course. Seven pregnant patients (2 Stage IB1, 5 Stage IB2) underwent radiation after radical hysterectomy was aborted due to positive regional lymph nodes. Three patients diagnosed during the first trimester were treated with radiation with the fetus in situ, and all had spontaneous abortions 20-24 days after the start of radiation (mean dose, 34 Gy). In all these cases, radiation was interrupted for only 3 days or less. There were no statistically significant differences in recurrence rates or survival between the pregnant group and the controls. Short term toxicity was comparable in pregnant and nonpregnant patients and easily controlled. Long term complications were more common in controls (12% in pregnant patients, 27% in controls), but this difference was not statistically significant. Most complications were likely related to radiation techniques (particularly the predominance of cobalt-60). CONCLUSIONS: Planned delay in treatment should be offered to pregnant patients with early stage squamous cell carcinoma in the late second and early third trimester. Patients diagnosed in the first or second trimester who are not good candidates for planned delay in treatment should be given radiation therapy immediately. It may be necessary to reconsider planned radical hysterectomy for pregnant women with Stage IB2 disease due to the high rate of lymph node positivity found on exploration. For patients with advanced disease, radiation therapy appears to be a safe and effective modality.

Adult↗

PubMed1997

Intraoperative electroneurodiagnostics (transcranial electrical motor evoked potentials) to evaluate the functional status of anterior spinal roots and spinal nerves during brachial plexus surgery.

Intradural spinal root lesions cannot be recognized by dissecting the brachial plexus and lead to ineffective surgery if they remain undetected. Therefore, patients need to undergo a diagnostic procedure to assess the intradural status of the spinal roots. Although motor recovery is the main goal of brachial plexus surgery, the techniques currently applied do not permit adequate evaluation of the anterior root. In search of an alternative, we performed intraoperative motor evoked potentials. Ninety spinal nerves in 19 patients suffering from brachial plexus lesions were dissected. Twenty-seven spinal nerves were avulsed; 8 nerves were disrupted and 17 were completely scarred, resulting in 25 stumps. Thirty-eight nerves appeared to be undamaged. On central stimulation, nerve compound action potentials were recorded from the exposed spinal nerves. Nerve compound action potentials could only be recorded from 21 stumps and from 32 apparently undamaged nerves. No recordings were obtained from 4 stumps and 7 spinal nerves in continuity. According to these findings, it is highly probable that surgery would have been insufficient in 10 spinal nerves if intraoperative motor evoked potentials had not been performed. We conclude that (1) intraoperative motor evoked potentials are an effective means for investigating the functional status of anterior motor roots and motor fibers in exposed spinal nerves, and (2) the use of motor evoked potentials should be considered during brachial plexus surgery to improve interventions.

Action Potentials↗

PubMed1995

Stage I squamous cell cervical carcinoma in pregnancy: planned delay in therapy awaiting fetal maturity.

PURPOSE: It is not known whether intentional delay to allow fetal maturity in patients with Stage I cervical carcinoma diagnosed during pregnancy will affect the survival of these patients. The purpose of this study is to report our experience with invasive squamous cervical carcinoma after planned delay in therapy for fetal indications, to assess maternal morbidity due to treatment delay, and to report maternal and fetal survival. METHODS: Between 1989 and 1994, eight pregnant women with Stage I squamous cervical carcinoma, who declined immediate therapy in order to improve fetal outcome, were prospectively followed until the late third trimester. Serial MRIs were used to follow the lesion in two patients. RESULTS: Stage IB cervical cancer was diagnosed in seven pregnant women. All lesions were less than 2.5 cm. The mean diagnosis-to-treatment interval was 109 days (range, 21-201; median, 112). One woman conceived in the cycle after diagnosis and had a diagnosis-to-treatment interval of 282 days. All were delivered by cesarean section-radical hysterectomy late in the third trimester. There was no clinical progression of disease detected during any of the pregnancies. Serial MRI examination confirmed stable disease in one patient and suggested an increase in tumor volume in one patient that was not pathologically confirmed. All are alive and disease free after a mean follow-up of 37 months (range, 13-68; median, 33). Neonatal morbidity was encountered in one infant (spontaneous pneumothorax). CONCLUSIONS: With a median follow-up of 33 months, patient-requested delays in therapy between 3 and 40 weeks (mean, 19) did not affect progression.

Adult↗

PubMed1995

Motor evoked potential as a reliable method to verify the conductivity of anterior spinal roots in brachial plexus surgery: an experimental study on goats.

The goal of this experimental study was to confirm the reliability of motor evoked potential (MEP) in testing the function of anterior motor roots in brachial plexus surgery. On central stimulation, nerve compound action potentials (NCAPs) are registered from the exposed spinal nerves. If NCAPs can be recorded, the anterior root is considered to be intact. Two factors might cause positive recordings even in the presence of an avulsed anterior motor root: volume conduction, and impulse transmission through an intact posterior root. In five Nubian goats, spinal nerves C6, C7, and their corresponding spinal roots were dissected. On central stimulation, NCAPs were repeatedly recorded from the surface of all ten spinal nerves. Then, the anterior motor roots were transsected and central stimulation repeated. NCAPs disappeared irreversibly in all ten tested spinal nerves. The experiment showed that, on central stimulation, NCAPs cannot be recorded from spinal nerves unless the anterior root is intact.

Animals↗

PubMed1995

Intraoperative electroneurodiagnostics to detect a second granuloma in the cubital area of median nerves affected by leprosy: a new approach to prevent incomplete surgery.

A recent work reports on the necessity to localize the most proximal site of leprous ulnar neuritis with intraoperative electroneurodiagnostics. In the present study we wanted to verify the applicability of this method on leprous median nerves. In six patients, seven median nerves were exposed at the wrist, all showing a typical leprous granuloma there. Spinal roots C5 to Th1 were then stimulated intraoperatively, evoking efferent mixed nerve compound action potentials (NCAPs) which were registered from the nerve's surface. No recordings could be obtained on the granuloma in all patients, neither distally nor shortly proximal from it, nor even further central at the forearm's proximal third where the median nerve exits the cubital area. Prior to dissecting the nerves in this precarious region, they were exposed at the arm's distal third, looking inconspicuous in all cases. Recordings could finally be obtained there, and subsequent exposure further proximal showed no increase in amplitude of the NCAPs, but there was a sharp decrease distally. In all cases, subsequent dissection of the cubital area revealed a second leprous granuloma extending variably from the distal third of the arm to the two heads of the pronator teres muscle, requiring microsurgical release. Intraoperative spinal root stimulation is an effective method to detect a second leprous granuloma and to avoid incomplete surgery in median nerves affected by leprosy.

Action Potentials↗

PubMed1994

Intraoperative spinal root stimulation to detect most proximal site of leprous ulnar neuritis.

In 10 patients with leprous ulnar neuritis, we investigated the most proximal site of lesion in the affected nerves. Spinal roots C8 and T1 were stimulated intraoperatively to evoke efferent mixed compound nerve action potentials which were recorded from the exposed ulnar nerves. The site at which amplitudes reached a maximum was considered the most proximal site of lesion. Nerve damage was found far proximally from the thickened segments in otherwise inconspicuous sections. Epineuriotomy within these apparently unaffected segments revealed fibrosis of the interfascicular epineurium in 9 patients, which is an indication for microsurgical interfascicular neurolysis.

Action Potentials↗

PubMed1993

Clinical application of motorsensory differentiated nerve repair.

Since 1979 acetylcholinesterase has been used in clinical practice for motor sensory differentiation. It was first used for median and ulnar nerve injuries at the wrist. Recently the application was extended to secondary nerve repair, including plexus reconstruction. The aim of this study was to present, for the first time, clinical results of motor sensory differentiated median and ulnar nerve repair and to show the advantage of this method in secondary repair. We compared a group of nine patients with motor sensory differentiated median and ulnar nerve repair with a group of 13 patients without motor sensory differentiation. Sensibility testing, strength measurements, and anatomical examinations were performed. The hand function was expressed in percentage values. Compound muscle action potentials and sensory antidromic conduction velocities were measured electroneurographically. Sensibility recovery was significantly better after motor sensory differentiated median nerve repair (P < 0.05). In secondary nerve repair acetylcholinesterase was used additionally for evaluating the level of resection of the proximal stump. The time required for perioperative histochemical differentiation has now been reduced to 2 hr.

Acetylcholinesterase↗

PubMed1993

Peripheral nerve repair in the hand with and without motor sensory differentiation.

To investigate the value of motor sensory differentiated nerve repair, we examined a group of 9 patients with motor sensory differentiated nerve repair and a group of 13 patients without motor sensory differentiated nerve repair. The clinical and electroneurographic findings were compared. For the clinical examination, Millesi's scoring system was used. The hand function after motor sensory differentiated median nerve repair was 72% +/- 16% compared with 57% +/- 14% without motor sensory differentiation. The hand function after motor sensory differentiated median and ulnar nerve repair was 53% +/- 12% compared with 43% +/- 24% without motor sensory differentiation. After ulnar nerve repair the achieved values for hand function were high even without motor sensory differentiation. Our results indicate that intraoperative motor sensory differentiation of injured nerves is helpful to reestablish particularly the sensory function in median nerve injuries.

Action Potentials↗

PubMed1993

Central nervous system function after cardiopulmonary bypass.

In a prospective study, an elderly group of patients (n = 63, 47 male, 16 female, age 40-65 years) was examined before and after open-heart surgery under cardiopulmonary bypass: postoperatively, 19 patients (30%) showed no clinical neuropsychiatric symptoms, whereas in 35 patients (56%) mild or transient neurological signs and in nine (14%) severe neurological complications were found. The postoperative EEG changes were characterized by a slight delta-theta increase, an alpha decrease and a significant slowing of the dominant frequency from 9.7 to 9.3 Hz. In brainstem auditory evoked potentials no changes were found, and in somatosensory evoked potentials (median nerve) the latency of the early cortical component, N20, increased. Cardiovascular reflexes showed increased changes, similar to those found in autonomic neuropathies. In the neuropsychological test battery, the Visual retention test (Benton) and the Rorschach test showed slight postoperative improvement, whereas other psychometric variables (flicker fusion frequency, reaction time) did not change. Despite an improved operative technique some minor clinical and neurophysiological disturbances of the central nervous system remain. However, specific pre- or peri-operative risk factors for these postoperative disturbances or complications could not be identified.

Adult↗

PubMed1993

Occurrence of epileptiform activity in the routine EEG of epileptic patients.

In a retrospective study, the occurrence of epileptiform activity (EA) in routine EEG records of epileptic patients was investigated. Data were obtained from 1078 EEGs of 373 patients (199 men and 174 women; aged 17-87 (mean 34.2 +/-14.7)). The percentage of 38% of patients with EA in a single EEG could be increased to 77% by repeated records. After the 5th record however, the gain in new information decreased remarkably. No differences between seizure types could be detected. There was a relationship between EA and nonspecific EEG abnormalities. High EA rates were found for short time intervals since last seizure, young patients, long durations of the seizure disorder and for high seizure frequencies.

Adolescent↗

PubMed1993

Clinical and electroneurographic evaluation of sensory/motor-differentiated nerve repair in the hand.

In 17 patients acetylcholinesterase activity was used to differentiate between sensory and motor fascicles in median and ulnar nerve repair of the hand. Eleven patients received follow-up evaluation 1 to 11 years after surgery, and at that time clinical and electroneurographic examinations were performed to evaluate the techniques. Clinical examination showed that four patients had regained on average 71.9% of hand function after median nerve repair, one patient had regained 83.6% of hand function after ulnar nerve repair, four patients had regained on average 53.3% of hand function after median and ulnar nerve repair, and two patients had regained on average 43.5% of hand function after median and partial ulnar nerve repair. The contribution of the ulnar nerve to reinnervation of the thenar muscles was 68.5%, whereas the median nerve did not contribute to reinnervation of the hypothenar muscles. Distal latencies for the median nerve showed a delay of 36% of the upper limit of normal value, and those for the ulnar nerve revealed a delay of 21.5%. This study demonstrated that sensory/motor-differentiated nerve repair of the median and ulnar nerves is possible and can be proven electroneurographically.

Adult↗

PubMed1991

[The significance of laboratory findings in long-term antiepileptic therapy].

A retrospective study of 316 patients (173 men, 143 women; mean age 39 [17-87] years) who had taken antiepileptics (phenytoin, phenobarbital, carbamazepine, valproic acid) for at least six months, was carried out to assess the biochemical and haematological changes in relation to the drug used, the therapeutic programme and the drug serum levels. The most frequent change was isolated elevation of gamma-GT (9-89% of cases depending on the drug), followed by elevation of alkaline phosphatase (16-44%). Increases in the transaminases GOT (4-13%) and GPT (4-19%) were infrequent and minor. Changes in the blood picture were very infrequent and never more than minimal. Correlation between all these changes and serum drug levels was poor (r less than 0.15). Correlations between drug serum level and dose were found in the case of phenobarbital (r = 0.6) and valproic acid (r = 0.5). There was hence no evidence of any clear connection between the biochemical findings and the serum concentrations of antiepileptic drugs or their-dosage. The results indicate that undue importance has previously been attached to routine checks of biochemical parameters; abnormal biochemical findings by themselves are not usually enough to necessitate changes in treatment. Determination of biochemical and haematological parameters is necessary only if there are clinical grounds for it such as suspicion of side effects, the occurrence of epileptic attacks despite therapy, or change from one drug to another.

Adolescent↗