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R Laskawi

Publications and source records attributed to R Laskawi.

At least 37 records · Page 2Linked to original sources
PubMed2000

Transient changes in cortical distribution of S100 proteins during reorganization of somatotopy in the primary motor cortex induced by facial nerve transection in adult rats.

In adult rats, the primary motor cortex (MI) comprises a somatotopic map of muscle representations. This somatotopy is modified after transection of the facial nerve (N7x). Mapping with cortical stimulation revealed that the underlying cortical reorganization is biphasic. Primary changes cause a transient disinhibition of long cortico-cortical connections in both hemispheres. While the first reaction vanishes within a few hours, short intra-areal connections are disinhibited within MI contralateral to N7x. The resulting co-operation between adjacent parts of MI persists as long as peripheral reinnervation is prevented. Cellular mechanisms underlying this cortical reorganization are largely unknown. Here, we utilized changes in immunoreactivity of S100 proteins (S100-IR) known as a sensitive indicator of astroglial reactions during plastic reactions in the central nervous system. Within 1 h of N7x, zones with enhanced S100-IR appeared in both hemispheres. Between 3. 5 and 18 h, reaction patterns with changing topography were transiently prominent in many cortical areas including parts of MI which surrounded the facial muscle representation fields. After 24 h, the facial muscle representation contralateral to N7x became labelled while S100-IR enhancement disappeared in most of the cortex. S100-IR-enhancement vanished completely during the next day of survival. Data presented suggest that (i) enhancement of S100-IR labels cortical tissue during the functional reorganization that is induced by N7x, (ii) large parts of the cerebral cortex participate in the reorganization, before it is finally focused on the representation field of MI that corresponds with contralateral N7x, and (iii) temporo-spatial patterns of astrocytic reactions apparently play a role in the underlying plasticity reaction.

Animals↗
PubMed2000

The effect of local injection of botulinum toxin A on the parotid gland of the rat: an immunohistochemical and morphometric study.

PURPOSE: In this investigation, the effect of a local injection of botulinum toxin A on the concentration of acetylcholinesterase in the parotid gland of the rat was examined. MATERIALS AND METHODS: After local injection into the parotid glands of female Wistar rats, the treated glands were excised, and immunohistochemical staining for acetylcholinesterase was performed. To discover possible changes in cell morphology after local application of botulinum toxin A, morphometric measurements also were performed on the excised parotid glands. RESULTS: In contrast to the untreated, physiologic saline-injected, glands, there was a decrease in the concentration of acetylcholinesterase in the glands treated with botulinum toxin. No persistent changes in the number of acinar cells could be observed. CONCLUSIONS: Because the cholinergic pathway of the autonomic nervous system has great importance in the secretion of fluid from the salivary glands, blocking this pathway and local application of botulinum toxin offers a possible therapeutic option for the treatment of hypersalivation in various otolaryngologic and neurologic diseases.

Acetylcholinesterase↗
PubMed1999

Cytologic diagnosis of adenoid cystic carcinoma of salivary glands.

The cytomorphologic features in fine-needle aspiration (FNA) biopsies from 31 primary and 33 recurrent adenoid cystic carcinomas (ACC) were investigated. The correct FNA diagnosis was established in 24 of 31 primary ACC (77%). The diagnostic clue in aspirates from ACC are large globules of extracellular matrix, partially surrounded by basaloid tumor cells. In FNAs with predominance of basaloid tumor cells, but lacking characteristic globules, all other benign and malignant salivary gland tumors of epithelial-myoepithelial differentiation should be considered in the cytologic diagnosis. Pleomorphic adenoma is most frequently confused with ACC, and therefore, the cytologic findings in FNAs from 50 pleomorphic adenomas were compared with those diagnosed as ACC. Furthermore, rare neoplasms of salivary glands with epithelial-myoepithelial cell differentiation, including basal-cell adenoma and carcinoma, epithelial-myoepithelial carcinoma, and polymorphous low-grade adenocarcinoma, as well as some nonsalivary gland neoplasms presenting an adenoid cystic pattern, must be considered. The cytologic features of these entities are discussed in detail with respect to the cytologic diagnostic criteria of ACC.

Adenoma, Pleomorphic↗
PubMed1999

Immunohistochemical and morphometric investigations of the influence of botulinum toxin on the submandibular gland of the rat.

Immunohistochemical methods were used to study the effects of botulinum toxin A on the concentration of acetylcholinesterase in the submandibular gland of the rat. The toxin was injected into the glands of healthy adult female Wistar rats and immunohistochemistry performed on the excised organs. Morphometric measurements were also carried out to study changes of cell morphology after local applications of botulinum toxin A. Compared with untreated glands or glands injected with saline there was a decrease of acetylcholinesterase in the glands treated with botulinum toxin. As the cholinergic pathway of the autonomic nervous systems plays an important role in eliciting secretion from the salivary glands, inhibition of secretion by local application of botulinum toxin could be considered a therapeutic option for the treatment of various diseases affecting salivary gland function.

Animals↗
PubMed1999

Gustatory sweating: clinical implications and etiologic aspects.

PURPOSE: It was the aim of this study to provide detailed general information on the clinical picture of different kinds of gustatory sweating, including reevaluation of a series of patients who underwent parotidectomy, removal of the submandibular gland, or neck dissection. PATIENTS AND METHODS: This study summarizes the statements of 548 patients questioned about the occurrence of gustatory sweating after parotidectomy (n = 296), extirpation of the submandibular gland (n = 79), and neck dissection (n = 173). RESULTS: After parotidectomy, 45% of the patients had noticed gustatory sweating. In most of them (70%), the symptoms began within 6 months after surgery. Gustatory sweating developed in only one patient with submandibular extirpation (1.5%), and not at all after neck dissection. Most patients (52%) reported that the symptoms occurred independent of the kind of food ingested. These results show that the "masticatory component" is an important trigger for Frey's syndrome. Application of Minor's test localized gustatory sweating mainly in the region of previous parotid lobe removal, but also in other areas deriving their sensory supply from the auriculotemporal, greater auricular, and lesser occipital nerves. The size of the area affected by the sweating was similar after lateral and total parotidectomy. When evaluating clinical symptoms, subjective assessment by the patients seemed to play a major role. After submandibular extirpation and neck dissection, some patients reported gustatory sweating that was not verified by Minor's test. CONCLUSION: There is general agreement that the cause of gustatory sweating is sympathetic or parasympathetic innervation of previously denervated sweat glands, initiated by gustatory triggers. The location of the "erroneous innervation" depends on the type of lesion. In cases after parotidectomy, misdirected parasympathetic regeneration is the model integrating all known factors into a rational concept. For didactic and systematic-pragmatic reasons, a clinically oriented classification of gustatory sweating (types I to III) seems to be useful.

Chi-Square Distribution↗
PubMed1999

[Possible one-dimensional determination of cortical representative fields of mimetic lower lip muscles by transcranial magnetic stimulation].

BACKGROUND: Recent reports as well as results from animal studies indicate changes of cortical organization in patients with facial palsy with a decrease in size of the face-associated cortical representation area. With regard to these alterations, there are no detailed reports in the literature about the possibility of a cortical mapping of mimetic muscles by TMS. METHOD: In 21 healthy volunteers we investigated the amplitude and the onset latency of motor evoked potentials (MEPs) from the depressor anguli oris and depressor labii inferioris muscles during cortical transcranial magnetic stimulation by use of a figure-8-shaped coil (double 70 mm coil) as a function of the scalp positions stimulated in order to establish a reproducible representation area along the interaural line. RESULTS: Cortical evoked MEPs characterized by onset latencies of 6-30 ms were elicited by contralateral and ipsilateral stimulation from coil positions between 4 and 13 cm lateral to the vertex. Maximal responses (mean amplitude 1.5 +/- 0.8 mV contralateral, 0.8 +/- 0.5 mV ipsilateral) with shortest mean onset latencies (11.5 +/- 1.5 ms contralateral, 12.2 +/- 2.8 ms ipsilatral) were observed at a coil position of 10 cm latral to the vertex. CONCLUSION: TMS offers a noninvasive method of one dimensional quantification of the cortical representation area of lower lip mimetic muscles.

Brain Mapping↗
PubMed1999

[Postoperative antibiotic therapy of cervical lymphadenitis caused by nontuberculous, atypical mycobacteria].

BACKGROUND: Cervical lymphadenitis caused by atypical mycobacteria is increasingly observed in immunocompetent children between 1 and 5 years of age. Surgical excision of all affected lymph nodes represents the treatment of choice. However, due to the infiltrative nature of the disease, surgery is occasionally unable to provide a complete cure and is associated with a high risk of recurrence. Such cases might derive benefit from an additional antibiotic therapy. METHODS: The study includes 4 children with demonstrated or clinically suspected nontuberculous mycobacterial lymphadenitis, in whom partial surgery had been performed. Postoperatively, two patients were treated with clarithromycin, rifabutin, and protionamide, the others with clarithromycin alone. Antibiotics were administered orally for 6-12 weeks and were continued four weeks after local signs of inflammation were no longer detectable. RESULTS: In all cases, symptoms of lymphadenitis resolved within 1-2 months and did not recur. One patient was affected by WHO grade I leukopenia after 6 weeks, which soon disappeared after administration of rifabutin and protionamid had been discontinued. CONCLUSIONS: Postoperative antibiotic therapy seems to be an effective approach to treat residual disease following incomplete surgery. It remains to be clarified, however, if such a therapy should comprise combinations of agents or if administration of clarithromycin alone might be sufficient.

Anti-Bacterial Agents↗
PubMed1998

Recurrent pleomorphic adenomas of the parotid gland: clinical evaluation and long-term follow-up.

We report 94 patients with recurrent pleomorphic adenomas of the parotid gland who were referred to our clinics after operations elsewhere. In 78 patients (83%) enucleation was the surgical technique used to remove the tumour. Patients with more than one recurrence were significantly younger than patients who had only one. Many recurrent adenomas (44%) were multifocal. In 20 (21%) further recurrences became obvious after we had operated on them. The mean time interval before recurrence ranged from 7.3 to 10.1 years. Twenty patients (14%) had persistent motor disorders of the facial nerve after operation for recurrence (n = 143). Twenty eight of the 84 patients from whom follow-up data could be obtained developed Frey's syndrome (33%). Our data support the importance of an adequate initial operation to avoid recurrences of pleomorphic adenomas in the parotid gland.

Adenoma, Pleomorphic↗
PubMed1998

Extraglandular Warthin's tumours: clinical evaluation and long-term follow-up.

Nine patients with extraglandular cystadenolymphoma (Warthin's tumour) were treated between 1965 and 1995 at the Department of Otorhinolaryngology, University of Göttingen. This number corresponds to 2.7% of all Warthin's tumours treated at our clinic so far. Although this rare tumour is well documented by case reports, a controlled follow-up study has not yet been published to the best of our knowledge. The retrospective investigation presented here gives the patients' clinical data and documents therapeutic success. Our results show the complete absence of recurrences after surgical excision of extraglandular cystadenolymphomas.

Adenolymphoma↗
PubMed1998

Clinical evaluation and surgical management of congenital preauricular fistulas.

PURPOSE: The retrospective investigation evaluated the clinical data on patients with a preauricular fistula with respect to demographic factors, symptoms, preoperative diagnosis, and surgical therapy. Follow-up studies served to critically assess the outcome of the operations. PATIENTS AND METHODS: The records of 62 patients were studied. Patients were divided into two groups: those operated on for the first time for a preauricular fistula and those operated on for a recurrence. Controlled follow-up was performed by means of a standardized questionnaire filled out by both the patients' physicians and the patients themselves. RESULTS: The mean age of patients operated on for the first time was 16 years, and that of patients operated on for a recurrence was 22 years. Although the overall rate of recurrence was 21%, it differed widely between groups (14% in first operations and 42% in patients operated on for the first time for a recurrence). These figures are within the lower range of the recurrence rates previously reported. Serious side effects, such as persistent damage to the facial nerve, were not observed. CONCLUSIONS: Operative management of a preauricular fistula is a treatment with few side effects that should be offered to each patient with such a malformation. Because the first operation is decisive for the further course of the condition, surgery should be performed under optimum conditions to avoid recurrence.

Adolescent↗
PubMed1998

Retrospective analysis of 35 patients with acinic cell carcinoma of the parotid gland.

PURPOSE: This retrospective study evaluated data pertaining to the history, symptoms, treatment, and prognosis of a series of patients treated for acinic cell carcinoma (ACC). PATIENTS AND METHODS: Data were based on the records of 35 patients. Follow-up was done by analyzing their records and contacting the referring doctors. RESULTS: In 71% of the ACC patients, painful swelling of the lateral region of the face was the main symptom. Facial paralysis occurred in 11% of cases before treatment. Tumor recurrence after therapy was noted in 42% of cases. Highly differentiated ACC was the most frequent histologic subtype (74%). The grade of differentiation of the tumor was decisive for the prognosis. Highly differentiated ACC had a better prognosis (2 years overall survival, 100%; 5 years overall survival, 83%; 10 years overall survival, 50%) than lowly differentiated tumors (2 years overall survival, 70%; 5 years overall survival, 50%; 10 years overall survival, 30%). CONCLUSION: ACC is a rare tumor located mainly in the parotid gland that is characterized by some special attributes. Surgery is the therapy of choice. Prognosis depends mainly on the histologic subtype.

Adolescent↗
PubMed1998

Aplasia of the depressor anguli oris muscle: a rare cause of congenital lower lip palsy?

Congenital unilateral lower lip palsy (CULLP) with or without additional malformations is a well-known limited variation of congenital unilateral facial palsy. Some electromyographical studies referred to a hypoplasia or an aplasia of the depressor anguli oris muscle. However, no attempt has been made to investigate the cause for this mimical disorder by using imaging procedures. We examined the occurrence of the depressor anguli oris muscle in 7 patients presenting with congenital lower lip palsy by using B-scan sonography. In 6 of the patients, the muscle was well-developed on the affected side, but only in one patient the muscle seemed to be completely absent. Thus, in the majority of cases, hypoplasia or aplasia of the depressor anguli oris muscle is obviously not the reason for this mimical disorder. This observation may be important with regard to a possible therapeutic management.

Adult↗
PubMed1998

[Isolated paralysis of the ramus marginalis mandibulae nervi facialis: clinical aspects, etiology, diagnosis and therapy. An overview].

BACKGROUND: Disorders of lower lip in facial expression are mostly caused by functional impairment of the marginal mandibular branch of the facial nerve. In a typical case, active exposure of the incisors of the mandible is not possible and the lip appears distorted towards the healthy side. The most frequent cause of a lesion of the marginal mandibular branch is iatrogenic injury during operations in the mandibular or parotid region. DIFFERENTIAL DIAGNOSIS: Functional disorders of the platysma, congenital hypoplasia or aplasia of the lower lip muscles, and defective healing following facial palsy may lead to a similar disorder which, however, must be differentiated from an isolated paralysis of the marginal mandibular branch. TREATMENT: In addition to inactivation of the nerve branch on the opposite side, several surgical procedures have been described to achieve not only aesthetic, but also functional rehabilitation of lower lip expression. The present review gives an overview on the causes, clinical appearance, diagnosis, differential diagnosis, and therapy of unilateral isolated paresis of the marginal mandibular branch of the facial nerve.

Facial Expression↗
PubMed1998

Up-to-date report of botulinum toxin type A treatment in patients with gustatory sweating (Frey's syndrome).

Several therapeutic approaches exist to treat gustatory sweating (Frey's syndrome) following parotidectomy. Because of the lack of effective treatment, a new therapeutic modality using botulinum toxin injections was presented previously by our group. The duration of the demonstrated positive effect was essentially unknown so far. Based on our experiences using this technique since December 1993, the purpose of this clinical investigation was to make an up-to-date report and demonstrate the duration of effect of BOTOX injections in patients with severe gustatory sweating. Nineteen patients with severe gustatory sweating have been treated with BOTOX by intracutaneous injections into the affected skin areas. The maximal follow-up time was 33 months. The results were obtained by interviews and controls using Minor's starch iodine test. In all treated cases (n = 19 patients, 22 treated sides) gustatory sweating ceased completely within 2 days. Side effects were absent. In 12 patients gustatory sweating reappeared. The mean duration of effect was 17.3 months (subjective personal communication of 18 patients). Findings show that intracutaneous injection of BOTOX is a highly effective, safe, and minimally invasive treatment of Frey's syndrome with long-lasting therapeutic effect.

Adolescent↗