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Biomedical subjects

R Laskawi

Publications and source records attributed to R Laskawi.

At least 55 records · Page 3Linked to original sources
PubMed1997

Cytologic diagnosis of acinic-cell carcinoma of salivary glands.

The cytologic findings in fine-needle aspiration (FNA) biopsies obtained from 40 primary and 18 recurrent acinic-cell carcinomas (ACC) were retrospectively analyzed. Cytomorphologically, ACC is characterized by acinar differentiated tumor cells. In addition to these diagnostic clue cells, other types of neoplastic cells including vacuolated cells, cells resembling oncocytes, and nonspecific glandular cells are encountered. A pronounced lymphocytic reaction is a hallmark in 10% of ACC aspirates. Both the variety of tumor cell differentiation and the pronounced lymphocytic reaction observed in ACC aspirates may result in confusion with other salivary gland lesions. The differential diagnosis of ACC encompasses adenocarcinoma, mucoepidermoid carcinoma, pleomorphic adenoma, Warthin tumor, sebaceous lymphadenoma, benign lymphoepithelial lesion, sialoadenosis, sialadenitis caused by radiotherapy, and lymphadenitis. Primary ACCs were correctly diagnosed in 68%; additionally, ACC was suspected or included in the differential diagnosis in 15%. Increased familiarity with the spectrum of cytomorphologic findings and the potential diagnostic pitfalls in ACC will improve the cytodiagnosis of this neoplasm.

Biopsy, Needle↗
PubMed1997

Rapid astroglial reactions in the motor cortex of adult rats following peripheral facial nerve lesions.

We report on changes in the motor cortex of adult rats that rapidly and transiently followed various types of facial nerve lesions. These reactions led to enhanced immunoreactivities of various astroglial markers: S-100 protein (a Ca2+- and Zn2+-binding protein predominantly located in the cytosol of astrocytes), glial fibrillary acidic protein (a cytoskeletal protein) and connexin 43 (the astroglial gap junction protein). Reactions could be visualized 1 h after the facial nerve lesion and disappeared within about 5 days after surgery. Combined lesions of the facial and trigeminal nerves modified the spatial pattern of the astroglial reaction, similar to intramuscular injections of botulinum toxin, which inhibits the release of acetylcholine in motor endplates. Data presented suggest that peripheral interference with muscular functions rapidly induces modifications in the motor cortex.

Acetylcholine↗
PubMed1997

Combination of hypoglossal-facial nerve anastomosis and botulinum-toxin injections to optimize mimic rehabilitation after removal of acoustic neurinomas.

This report refers to 10 patients treated with hypoglossal-facial nerve anastomosis and botulinum-toxin type A after removal of acoustic neurinomas. All patients who underwent this regimen showed reinnervation of mimic muscles after nerve anastomosis in all parts of the mimic musculature. Synkinesis could be observed in all patients. Botulinum-toxin injections into the orbicularis oculi muscle improved the functional outcome, leading to an approximation of the palpebral fissure width to the healthy side during heterogenous face movements. The mean duration of the toxin effect was 13.8 weeks. Side effects were rare. It can be stated that the combination of hypoglossal-facial nerve anastomosis and botulinum-toxin injections is suited to optimize mimic rehabilitation after removal of acoustic neurinomas.

Adult↗
PubMed1996

Biphasic reorganization of somatotopy in the primary motor cortex follows facial nerve lesions in adult rats.

Effects of facial nerve transection were studied on muscle responses evoked by electrical stimulation in the primary motor cortex (MI) of adult rats. In intact animals, activated muscles varied according to the somatotopic representation map, and responses were restricted to the contralateral side. Unilateral transection of the facial nerve extinguished contralateral vibrissal responses, while ipsilateral vibrissae began to respond within 4 min. This abnormal response (primary change) was transient and gradually disappeared within hours to days. Instead, contralateral movements of forepaw and eye/eyelid muscles could be evoked from increasing portions of the former vibrissal field (secondary change), in which many points became unresponsive. After 4 days, the former vibrissal field had shrunk to a small central part, where ipsilateral vibrissae responsiveness remained. The secondary modification was stable for at least 2 weeks. Since the primary change is rapid, transient and may be mimicked by picrotoxin, it may be based on disinhibition of commissural connections, while the secondary change is longlasting and therefore may include some form of reorganization of associational synapses.

Animals↗
PubMed1996

Changes in glial fibrillary acidic protein immunoreactivity in the rat facial nucleus following various types of nerve lesions.

We report about changes on astrocytes in the facial nucleus of the rat following various types of peripheral nerve lesions. Astrocyte-specific glial fibrillary acidic protein (GFAP) was labeled by immunohistochemistry and served as a marker for these changes. Increased GFAP immunoreactivity was found in the facial nucleus on the lesioned side within 2-3 days after axotomy. This change lasted longer (up to 1 year) when axon regeneration was prevented or delayed by placing a metal clip on the proximal nerve stump. Lesion of the trigeminal nerve prior to axotomy reduced the degree of GFAP immunoreactivity. No side differences were observed after botulinum toxin application.

Animals↗
PubMed1996

Surgical management of pleomorphic adenomas of the parotid gland: a follow-up study of three methods.

PURPOSE: This retrospective study evaluated data pertaining to history, symptoms, diagnosis, and mode of therapy of patients treated for pleomorphic adenoma of the parotid gland. PATIENTS AND METHODS: The records of 475 patients were reviewed. Follow-up was done by questionnaires sent to the referring doctor. RESULTS: The total rate of recurrence was 0.9% after 475 operations for pleomorphic adenoma of the parotid gland. One recurrence (0.7%) was reported for the group with superficial parotidectomy and none for the group with total parotidectomy. The rate of postoperative side effects was also low. The facial nerve was affected in 1.4% after superficial parotidectomy, and in 3.3% after total parotidectomy. CONCLUSION: The results of this follow-up study show that superficial parotidectomy for pleomorphic adenoma located in the superficial lobe of the parotid gland provides adequate therapy and generally avoids recurrence and side effects.

Adenoma, Pleomorphic↗
PubMed1996

Surgical management of nonneoplastic diseases of the submandibular gland. A follow-up study.

A total of 233 patients with nonneoplastic diseases of the submandibular gland were treated between 1966 and 1992 at the otorhinolaryngology department of the University of Göttingen. Of them, 212 patients (91%) suffered from sialadenitis with or without sialolithiasis, and 21 (9%) suffered from other diseases. The first part of the present study analyzes the clinical data with regard to history, symptoms, and therapy. It was found that in most cases (77%) extirpation of the affected gland had been the standard operation. In the second part, the surgical procedures applied are critically assessed. Extirpation of the submandibular gland proved to be an effective therapy in all patients. Side-effects were rare. The management of chronic sialadenitis caused by calculi should include extirpation of the submandibular gland. In case of calculi not causing inflammatory disease, lithotripsy should be considered.

Abscess↗
PubMed1995

Structural dynamics of synapses and synaptic components.

Learning and memory formation are apparently based on cascades of molecular and cellular processes with increasing time constants (ms to days and weeks), but even the most long-lasting effects are transient. Memory traces may permanently modify the behavior (activity patterns, gene expression) of neurons and neuronal networks. Therefore the question is raised whether our current view on the stability of synapses under normal conditions is tenable. Evidence is reviewed suggesting that as direct or indirect effects of modifications in bioelectrical activity and chemical trophicity, synapses may be remodeled and removed within days and weeks, and possibly within hours. Accordingly, species-specific connectivity patterns are not restricted to the standard architecture of the CNS, but (morpho-)genetics allow for a considerable number of alternative wiring patterns, which appear under unusual conditions during ontogenesis and in adulthood. Our present knowledge suggests that, rather than the formation of synapses, they are a selective process. Until now there is no direct method of measuring either synaptic reorganization or the average life span of synapses. Specific cases, however, allow to estimate synapse turnover during ontogenesis, at its lowest possible level. Such data suggest that each synapse is on average remodeled or replaced several to many times during normal developmental, e.g. in the cerebral cortex of Marmoset monkeys at the very least 5 to 10 times (corresponding to 250 million synapses eliminated per hour in area 17!). It is discussed how the consequences of synapse turnover could be utilized by learning processes. Conclusions are followed by an outlook.

Animals↗
PubMed1995

Surgical management of benign tumors of the submandibular gland: a follow-up study.

PURPOSE: This retrospective study evaluated data pertaining to history, symptoms, diagnosis, and mode of therapy of patients treated for benign tumors of the submandibular gland. PATIENTS AND METHODS: The records of 38 patients were reviewed. The patients were divided into three groups: pleomorphic adenoma (first operation), pleomorphic adenoma (second operation for recurrence), and other tumors. Follow-up was done by questionnaires sent to the patient and referring doctor. RESULTS: The vast majority of patients treated (92%) had had either a first or second operation for pleomorphic adenoma. Follow-up revealed that recurrence did not develop in the group of patients with primary surgery. However, one patient undergoing surgery for recurrent pleomorphic adenoma developed two recurrences. Two patients suffered from slight weakness of the lower lip. CONCLUSION: Tumor recurrence was found only in the cases of second operation after previous surgery for pleomorphic adenoma. Therefore, the first operation should extirpate the entire gland to minimize the risk of recurrence.

Adenoma, Pleomorphic↗
PubMed1995

[Exulcerating cystadenolymphoma of the parotid gland. A case report].

A recurrent adenolymphoma of the left parotid gland occurring in a 79-year-old woman is reported having caused an extensive ulceration of the epidermis, clinically suggestive of a malignant tumour. The ulcerative tumour process cannot be explained by a particular pattern of growth or a malignant transformation of the adenolymphoma. It is assumed that residual tumour cells of the initially incompletely removed adenolymphoma spread via a long-standing postoperative fistula to the epidermis leading to the uncommon ulceration.

Adenolymphoma↗
PubMed1995

Frey's syndrome: treatment with botulinum toxin.

The effectiveness of botulinum toxin injections for the management of Frey's syndrome was studied. Botulinum toxin A (approximately 0.5 Units/cm2) was injected intracutaneously into the affected skin area as determined by Minor's starch iodine test. Gustatory sweating in the treated skin area ceased completely within 1 week and has not reappeared (12 months follow up until now in the first treated case). There have been no side effects. It is concluded that local botulinum toxin injections are a highly effective and safe treatment for Frey's syndrome. Additional study is required to evaluate the duration of the therapeutic effect.

Botulinum Toxins↗
PubMed1995

[Therapy of Frey syndrome with botulinum toxin A. Experiences with a new method of treatment].

The effectiveness of botulinum toxin for the treatment of Frey's syndrome is demonstrated. Since December 1993, 14 patients with severe symptomatic gustatory sweating have been treated at the ENT Department, University of Göttingen. Botulinum toxin A (approximately 0.5 U/cm2) was injected intracutaneously into the affected skin area as determined by Minor's starch iodine test. Gustatory sweating in the treated skin area ceased completely within 2 days and did not reappear during the period of following (13 months maximum follow-up). There were no side effects. Findings show that local botulinum toxin injections are a highly effective, safe and minimally invasive treatment for Frey's syndrome. Moreover, this could be a new therapeutic tool for other forms of hyperhidrosis.

Adult↗
PubMed1994

Astrocytes as rapid sensors of peripheral axotomy in the facial nucleus of rats.

Facial nerve transection leads to functional and structural reactions in lesioned motor neurones and surrounding glial cells. Data from this study provide evidence that the most rapid reaction described so far consists of an increase in immunoreactivity of connexin-43 (cx-43), the predominant gap junction protein in astrocytes. The ipsilateral facial nucleus is selectively marked as early as 0.75 to 1.5 hours after axotomy, while the unlesioned side as well as the unoperated controls remain faintly stained. Thus, enhanced coupling capacity of astrocytes by gap junctions appears to be a sensitive indicator of modified neuronal-glial interaction in the CNS.

Animals↗
PubMed1994

Botulinum toxin treatment in patients with hemifacial spasm.

Hemifacial spasm is nearly always a unilateral disease of the facial musculature and is characterized by involuntary tonic or clonic cramps that considerably reduce the affected patient's quality of life. In the past, a number of different conservative and operative therapeutic procedures have been applied for the treatment of hemifacial spasm. In many cases these attempts failed to control the disease permanently or resulted in unwanted, sometimes strong, side effects. We report our own experiences with botulinum therapy in 29 patients with hemifacial spasm (78 therapeutic sessions). In our patients the mean duration of an effect after treatment with botulinum toxin was 18.2 weeks. Side effects were rare. Our results since 1990 at the University of Göttingen demonstrate that subcutaneous application of toxin from Clostridium botulinum to involved facial muscles represents a reliable method for successful treatment of hemifacial spasm.

Adult↗
PubMed1994

Orbicular synkinesis after facial paralysis: treatment with botulinum toxin.

Involuntary lid closure not rarely accompanies aberrant regeneration of nerve fibers after different types of facial paralysis. 23 patients with such synkinesis were treated with botulinum toxin injections into the orbicularis oculi muscle. After periocular injections all patients showed much improvement: a period of, on the average, 13 symptom-free weeks was followed by a period of minimal symptoms. There were only minor complications. Whenever repeated treatment is necessary, botulinum toxin proves to be an effective therapy for involuntary lid closure after defective healing following facial paralysis.

Adult↗