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Biomedical subjects

S Charabi

Publications and source records attributed to S Charabi.

At least 55 records · Page 3Linked to original sources
PubMed1994

Epithelial migration in mastoid cavities.

The epithelial migration in 18 dry ears with a cavity after surgery was studied by the ink-dot method and compared with the epithelial migration in 15 normal ears. A qualitatively normal centrifugal migration pattern was observed in all cavity ears. Considerable variation in migration speed was observed within the same cavity ear, thus a comparison with the migration speed in normal ears was impossible. No definite relationship was apparent between migration speed and the self-cleansing ability of the ear, which primarily appeared to be a function of the macroscopic appearance of the cavity (i.e. the presence of pockets or ridges). We conclude that epithelial migration is as important in maintaining the self-cleansing function and non-infected state in cavity ears as it is in normal ears.

Adult↗
PubMed1994

Histopathology and growth pattern of cystic acoustic neuromas.

In a series of 571 acoustic neuromas, 23 were identified as cystic tumors. An immunohistochemical study including nervous system-associated protein (S-100), glial fibrillary acidic protein (GFAP), neurofilament protein (NF), laminin, fibronectin, vimentin, factor VIII (von Willebrand factor)-related antigen, and the nuclear antibody Ki-67 was performed. The cyst walls contained numerous S-100-positive fibrils distributed throughout the whole extent of the walls. Laminin, fibronectin, and vimentin were predominantly located around the vessel walls, factor VIII was found inside the vessels. GFAP-positive lamellae occurred in 50% of the cases near the surface of the cyst walls. Ki-67 is an antigen associated with cell proliferation. The density of Ki-67-positive cells was found to be 36 times lower in 16 noncystic controls than in the 23 cystic neuromas, indicating that the increase in tumor size in cystic acoustic neuromas may be caused by expansion of the cysts and not by an actual increase in the growth rate of the tumor cells. The data achieved in this series may contribute to better planning of the surgical approach. Because of the risk of sudden expansion of cystic elements, a wait-and-see policy should not be applied to patients with cystic acoustic neuromas.

Adult↗
PubMed1994

Subcutaneous growth of human acoustic schwannomas in athymic nude mice.

In order to develop an in vivo model for growth of acoustic schwannomas, we studied tumor specimens from 10 patients, transplanted into a subcutaneous pocket of 67 nude mice. The number of tumors which survived or grew was 63 (94%). Obvious macroscopic growth was observed in 22 (33%), status quo in 28 (42%), and regression of tumor size in 13 (19%). The tumor disappeared in 4 cases (6%). Serial implantation was not possible due to the small amount of neuroma tissue in the surviving tumors. In animals with obvious macroscopic growth, neovascularization was clearly demonstrated. The presence of Schwann cells in the implants was confirmed immunohistochemically. The proliferative activity in the original and implanted tumors was evaluated by the proliferating cell nuclear antigen (PCNA) and Ki-67 nuclear antigen stainings and showed good correlation between primary tumors and implants. This in vivo tumor model will open new opportunities to study the biology of acoustic tumors and to test different therapeutic modalities.

Animals↗
PubMed1994

The choice of approach in surgery for acoustic neuromas (vestibular schwannomas).

The advantages and disadvantages of the different surgical approaches for surgery of vestibular schwannomas are described, as well as the problems in evaluating the outcome of the treatment, regarding especially the evaluation of facial nerve function and hearing capacity. The eclectic Copenhagen treatment algorithm is outlined: 1) All tumors measuring 25 mm or more on MRI are operated via the translabyrinthine approach. 2) All patients with PTA poorer than 30 dB, and SDS poorer than 70% are operated via the translabyrinthine approach. 3) Tumors less than 10mm extrameatally, and PTA better than 30 dB and SDS better than 70% are removed via the middle fossa route. 4) Tumors measuring 10-25 mm and PTA better than 30 dB and SDS better than 70% are operated via the suboccipital route. Finally some consequences of postponing surgical treatment is described, demonstrating that 74% of 127 tumors continued to grow with a mean of 3.4 mm increased tumor diameter per year, and that 75% of patients, who were candidates for hearing preservation surgery lost the candidature in the observation period.

Algorithms↗
PubMed1993

[Surgical treatment of otosclerosis. Long-term results].

UNLABELLED: At Glostrup Hospital, Copenhagen, exceptionally few stapedectomies were performed during the period 1979-1985. The audiological results five to eleven years after the operation were investigated in 64 patients. About half of the patients were operated using large fenester technique, the other half using small fenester technique. All patients but two were operated by the same expert surgeon. The initial results showed good stability with an unchanged median hearing gain of 30 dB. Eighty-five percent of the patients had an SRT < or = 35 dB HL in contrast to 89% at the 1-year follow-up (and five percent preoperatively). Eighty-two percent had an air-bone gap < or = 20 dB in contrast to 93% at 1-year follow-up (and 10% preoperatively). None of the patients had spontaneously developed severe sensorineural hearing loss, which was, however present in two patients as a direct result of the operation. In one of the patients it was caused by granuloma formation around the prosthesis, in the other patient it developed after a revision procedure. Both patients were operated using large fenester technique, which in general gave less satisfactory primary hearing improvement and less stable thresholds than small fenester technique. IN CONCLUSION: Even under conditions with few operations per year the overall long term results of stapedectomy are satisfactory when performed by few trained ear surgeons, and in particular if small fenester technique is used. The risk of sensorineural hearing loss is primarily related to the operation.

Adult↗
PubMed1993

[Acoustic neurinomas in Denmark. Incidence and therapeutic strategies].

The annual incidence of diagnosed acoustic neurinomas in Denmark during two 7-year-periods from mid 1976 to mid 1990 is compared. Data on all patients operated via the translabyrinthine, transtemporal and suboccipital approach, as well as data on non-operated patients, was collected from the entire country. During the first period, from June 1976 to June 1983, the incidence was 7.8 tumors per million per year. During the second period, from June 1983 to June 1990, the annual incidence rose to 9.4 tumors per million per year. The number of newly-diagnosed small tumors increased, and that of large tumors decreased. A significant increase was observed in Copenhagen. An incidence of 11 to 12 tumors per million per year, or nearly 60 newly-diagnosed tumors per year is thus expected around the year 2000. This limited number supports the continuation of the present centralized model of acoustic neurinoma surgery in Denmark.

Adult↗
PubMed1993

[Results of suboccipital removal of acoustic neurinomas in Denmark 1979-1990].

In the period from 1979 to 1990, a series of 59 patients with 59 acoustic neuromas were operated upon in five departments of neurosurgery by at least five different neurosurgical teams, employing the suboccipital approach. The perioperative mortality rate was 8.5%. Complications including hematoma, ventricular hemorrhage, meningitis, hemiparalysis, abducens nerve paralysis, recurrent nerve paralysis, postoperative wound infection and CSF leak were observed in 21 patients (35.6%). Radical removal of the tumor was not possible in 17 patients (28.8%). Converting the postoperative facial nerve function to the House-Brackmann (HB) classification, 34 patients (57.6%) were regarded as HB VI. Reconstruction of the facial nerve was attempted in 19 patients (32.2%). Attempts at preservation of hearing were unsuccessful in all patients. Failure to attain better results and the importance of the centralized Danish model of acoustic neuroma surgery are emphasized.

Adult↗
PubMed1993

Growth rate of acoustic neuroma expressed by Ki-67 nuclear antigen versus symptom duration.

The growth rate of acoustic tumors varies widely. An immunohistochemical study with Ki-67 monoclonal antibody was performed on a random sample of 21 acoustic neuromas. The tumors belonged to 2 well-defined groups: 1 with a short duration of preoperative symptoms (< 1 year) and 1 with a long duration of preoperative symptoms (> 5 years). The tumors were of small to medium size (7 to 27 mm), and no large, cystic, or Recklinghausen tumors were included. The tumor proliferative fraction expressed by monoclonal antibody Ki-67 was determined. The results revealed a significant relation between the tumor proliferative fraction and symptom duration. Tumors with a high proliferative status had a short preoperative symptom duration, while tumors with a low proliferative status had a long symptom duration. The clinical implications of these results are discussed.

Adult↗
PubMed1993

Histology and neuro-imaging in cystic acoustic neuromas.

Tumor configuration and attenuation on CT scan with contrast enhancement or gadolinium-DTPA-enhanced MR depends upon tumor histology. Various elements are responsible for the density on CT or MR, e.g. blood vessels, fatty tissue, connective tissue, calcium, necrotic tissue, hemorrhage and intra- or extratumoral cyst formation. In a series of 571 acoustic neuromas we found 23 cystic tumors. The diagnosis was based on neuro-imaging examination, confirmed at surgery and finally verified histologically. Eight tumors with small or large cysts were diagnosed by CT or MR scan as intratumoral, and 15 with large cysts were diagnosed as extratumoral. We found a good correlation between the histology of cystic acoustic neuromas and the CT or MR scans. The tumors were predominantly hypodense, corresponding to the cystic areas, but also iso- or hyperdense areas were observed, corresponding to other tissue types. Antoni type B tissue and xanthomatous areas were found in all 23 cases.

Cell Membrane↗
PubMed1992

Suboccipital acoustic neuroma surgery: results of decentralized neurosurgical tumor removal in Denmark.

From 1979 to 1990, a series of 59 patients with 59 acoustic neuromas were operated on in five departments of neurosurgery by at least five different neurosurgical teams, employing the suboccipital approach. Perioperative mortality rate was 8.5%. Complications including hematoma, ventricular hemorrhage, meningitis, hemiparalysis, abducens nerve paralysis, recurrent nerve paralysis, postoperative wound infection and CSF leak were observed in 21 patients (35.6%). Total tumor removal was not possible in 17 patients (28.8%). Converting the postoperative facial nerve function to House-Brackmann (HB) classification, 34 patients (57.6%) were regarded as HB 6. Reconstruction of the facial nerve was attempted in 19 patients (32.2%). Attempts at hearing preservation were unsuccessful in all patients. Failure to attain better results and the importance of centralized treatment of acoustic neuroma are emphasized.

Adult↗
PubMed1992

Incidence of acoustic neuromas.

The annual incidence of diagnosed acoustic neuromas in Denmark during two 7-year periods from June 1976 to June 1990 was compared, collecting all operated and non-operated tumors from the entire country. During the first period 278 tumors were diagnosed with an annual incidence of 38 tumors or 7.8 tumors per million per year. During the second period the annual incidence rose to 48 tumors and 9.4 tumors per million per year. There was a significant decrease of extrameatal tumor size from 33 to 26 mm and diminishing of giant tumors.

Denmark↗
PubMed1991

[False-positive diagnostic findings in acoustic neurinomas].

In the period from 1976 to 1990 Tos and Thomsen operated on 520 patients with acoustic neuromas using the translabyrinthine approach and five other patients were operated on via middle fossa approach. The diagnostic work up in all patients included: pure tone audiometry, tympanogram with acoustic reflexes, caloric test and brainstem audiometry. Since the late seventies, CT became the radiological investigation of choice to visualize the tumor. The first generation of CT failed to reveal tumors less than 1.5 cm in the extrameatal diameter, and pantopaque cisternography was necessary in some cases. The following generation of CT did not always reveal small intrameatal tumors, and false-negative results were reported. The incidence of false-positive CT findings in our series is calculated to be 0.6%. Three patients were operated on on account of false-positive CT. Peroperatively, adhesions in and around the internal porus were found in two cases while no pathology was found in the third case. Postoperatively, anacusis was observed in two cases. This could have been avoided if magnetic resonance imaging (MRI) with gadolinium contrast had been performed. In our opinion, MRI should be considered before a definitive surgical procedure is undertaken. Until MRI becomes more widely available, intravenous contrast-enhanced tomography followed by air cisternography is recommended in the diagnosis of small acoustic neuromas.

Adult↗
PubMed1990

[The value of magnetic resonance scanning in the diagnosis of small acoustic neurinomas].

This article describes three cases of acustic neurinoma in which both clinical examination and audiovestibular investigations raised strong suspicions of acustic neurinoma but no tumours could be demonstrated by CT. Magnetic resonance scanning employing gadolinium-DTPA revealed small intrameatal acustic neurinomas in all three cases. Attention is drawn to the fact that magnetic resonance scanning provides a new diagnostic possibility for acustic neurinoma and is a valuable supplement to the established diagnostic procedures in suspected acustic neurinoma even although CT reveals normal anatomical conditions in the internal auditory meatus.

Adult↗
PubMed1989

Myxoid tumours in the temporal bone.

Myxoid tumours have the essential common feature, that they are difficult to remove radically because of their gelatinous consistency. Only one previous report describes a myxoid tumour--a myxoma--located to the temporal bone. This paper presents two such tumours in the temporal bone, a myxoma and an extraskeletal myxoid chondrosarcoma. The clinical and histological features of these tumours and the operative treatment are described and discussed.

Adult↗
PubMed1989

[Diagnostic delay in cancer of the nasal cavity and the paranasal sinuses].

Malignant tumours of the nasal cavity and paranasal sinuses are rare. The incidence in the Western world is one per 100,000. The prognosis and therapeutic results are poor, as in most cases a considerable delay occurs before diagnosis. Doctor-delay is illustrated here by two cases a classical patient-delay by one. The etiology, histopathology, clinical manifestations and therapeutic possibilities are reviewed.

Adult↗