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P Bretlau

Publications and source records attributed to P Bretlau.

At least 19 recordsLinked to original sources
PubMed1992

Drift barriers in the postcartilaginous development of the mammalian otic capsule.

Postcartilaginous development of the otic capsule was studied in undecalcified histological material from rabbits following sequential fluorochromic time labeling of mineralizing tissues, using combined microradiography, fluorescence microscopy and osteoid staining. Early fetal bone formation was monitored by labelling of the experimental animals in utero. In contrast to the normal pattern of drift movements displayed by long bones and extracapsular cranial bone, capsular bone inside a zone immediately surrounding the perilymphatic space developed as a separate functional unit in which growth and modeling was absent. Bone tissue behavior appeared to depend on its spatial relation to the membranous labyrinth rather than histological characteristics. These findings suggest the role of inner ear tissues as a functional matrix in control of capsular bone dynamics beyond fetal life.

Animals↗
PubMed1992

Epidermal growth factor receptor expression on oral mucosa dysplastic epithelia and squamous cell carcinomas.

The expression of the receptor for epidermal growth factor (EGF) has been determined on oral squamous cell carcinomas. Immunoreactive receptor was localized using a monoclonal anti-EGF-receptor antibody which reacts with sequences in the external domain of the receptor. Frozen sections were studied from 40 patients with squamous cell carcinomas. In 16 sections from the patients with the squamous cell carcinomas, normal differentiated oral mucosa was included and in 7 of these the patients had received preoperative radiotherapy. Sections from 6 other patients with squamous cell carcinoma contained dysplastic epithelia. EGF-receptor-positive cells were present in the basal cell layer on normal differentiated oral mucosa. In sections from patients receiving preoperative radiotherapy the EGF-receptor-positive cells were also found in the spinous cells. In dysplastic epithelia nearly all cells stained for the receptor. The distribution and staining intensity of the EGF receptor varied in the oral squamous cell carcinomas, 36 were positive. The staining pattern in the carcinomas obtained from patients receiving preoperative radiotherapy was not altered qualitatively. Nearly all poorly differentiated cells were stained, but when the tumor was moderately to well differentiated a reduction in the extent of staining in certain areas was seen, paralleling the findings observed in the differentiated upper layers of the normal oral mucosa. This was most pronounced for the epithelial pearls, where the EGF-receptor-positive cells were localized to the undifferentiated cells in the periphery. The results of the present investigation confirm the presence of the EGF receptor on undifferentiated cells, with the extent of the staining reaction on oral squamous cell carcinomas varying inversely with cellular differentiation.

Adult↗
PubMed1992

Distribution of bone remodeling units in the otic capsule of the rabbit. A semiquantitative morphometric study.

Distribution of bone remodeling units (BRU) in relation to the perilymphatic space was studied in undecalcified temporal bones from adult rabbits labeled in vivo with bone-seeking fluorochromes. Based on recordings of focal bone formation, relative densities of BRUs inside concentric tissue zones around the inner ear spaces were estimated. Zonal densities of BRUs were found to decline towards the perilymphatic space, lending further support to the existence of a local inner ear mechanism in control of capsular bone tissue dynamics. The possible nature of this mechanism is considered briefly with special reference to inner ear electromechanic activity.

Animals↗
PubMed1992

Immunohistochemical detection of epidermal growth factor receptor in laryngeal squamous cell carcinomas.

Laryngeal squamous cell carcinomas from 15 consecutive preoperatively irradiated patients were investigated for the expression of epidermal growth factor receptor (EGF receptor). The study was performed on frozen sections by means of the 5-layer APAAP technique employing an antibody recognizing the extracellular part of the EGF receptor. In sections from 9 of the patients with laryngeal squamous cell carcinoma, normal differentiated epithelia were included. Sections from 6 of these patients, in addition, contained dysplastic epithelia. Expression of EGF receptor-like material was demonstrated in the basal cell layer of normally differentiated laryngeal epithelial and in dysplastic epithelia. Fourteen of the squamous cell carcinomas proved EGF receptor positive. Nearly all cells in the poorly differentiated carcinomas showed positive staining with the antibodies. In moderately to well differentiated carcinomas a reduction in the extent of staining was seen in certain areas. Especially for the epithelial pearls, the staining reaction was localized to the undifferentiated cells in the periphery. This finding corresponds to the staining pattern observed in the basal cell layers of normal epithelial. The present investigation confirms the expression of EGF receptor-like material in normal laryngeal epithelial, dysplastic epithelial and squamous cell carcinoma. The staining pattern was similar to that observed in oral squamous cell carcinomas, predominantly varying inversely with cellular differentiation.

Carcinoma, Squamous Cell↗
PubMed1992

Bone repair in the otic capsule of the rabbit.

The repair of 1 mm drill hole lesions in rabbit long bones and otic capsules was studied in undecalcified sections. Following surgery, bone formation was monitored during 12 weeks by intravital sequential time labeling with bone-seeking fluorochromes. In diaphyseal bone, initial repair by trabecular woven bone was accompanied by a transient remodeling response in primary repair bone and the surrounding compacta. In comparison, capsular defects showed a slightly deficient initial repair by woven bone which, once formed, persisted unchanged with no subsequent osteonal remodeling. In the surrounding capsule, the remodeling response was subtle and its duration much shorter. Moreover, the centrifugal distribution of bone remodeling units around inner ear spaces was preserved, suggesting that capsular repair is affected by the same morphogenetic field that controls perilabyrinthine growth, modeling and remodeling. The significance of these findings is briefly discussed in relation to otosclerosis and cochlear implant strategies.

Animals↗
PubMed1992

Epidemiology of nasopharyngeal and salivary gland carcinoma in Greenland.

From 1950 to 1989 one hundred and forty-four cases of either undifferentiated nasopharyngeal carcinoma (NPC) or salivary gland carcinoma (SGC) were diagnosed in Greenlanders, all born in Greenland. The Greenland SGC is an anaplastic carcinoma with histopathology and electronmicroscopic cytopathological alterations as found in undifferentiated NPC. Both NPC and SGC from Greenland and Alaska are associated with Epstein-Barr virus infection. The incidence rate of NPC based on newly diagnosed cases during the last 15 years is 12.7 for men and 9.2 for women. The same figures for anaplastic SGC are 3.4 and 3.1. These are among the highest incidence rates of Epstein-Barr virus associated carcinomas on record. From 1950 to 1989 there has been an increase in the rate of NPC. From the cumulated rate, it can be predicted that the number of cases will continue to increase during the years to come. During the ten year period 1980 to 1989 patients were questioned about their childhood life style and the family history was taken. The Inuit lifestyle is quite different from that of Europeans and Chinese, but in common with Chinese from Guangzhou (formerly Canton) Greenlanders have a high consumption of fish, fresh as well as dried. Familial clustering has been rarely reported, but in the present investigation 27% of the patients diagnosed between 1980 and 1990 had a positive familial history with one or more confirmed cases among first degree relatives.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

Remodeling patterns in the bony otic capsule of the dog.

Quantum-type bone remodeling was studied in undecalcified temporal bones and long bone specimens from adult mongrel dogs by means of combined microradiography, osteofluorochrome labeling, and osteoid staining. The overall turnover rate of capsular bone was estimated to be low compared to that of extracapsular compact bone. Evolving secondary osteons were distributed centrifugally relative to the perilymphatic space. Moreover, a zone of bone tissue enclosing perilymphatic spaces was found completely devoid of evolving secondary osteons. Throughout the otic capsule, segmentary perivascular foci of resorption and formation were present. These findings indicate that remodeling of capsular bone is subject to sustained local inhibition. The significance of this conclusion is considered with special reference to otosclerosis.

Animals↗
PubMed1990

Melanotic schwannoma of the orbit. Immunohistochemical and ultrastructural study of a case and survey of the literature.

Light microscopical, immunohistochemical and ultrastructural study of a case of melanotic (pigmented) schwannoma in the left orbit of a 22-year-old man is presented. The tumour caused exophthalmus for three months and was located under the eyeball. Partial removal resulted in recurrence after three years. The recurrent tumour with extension to the nasal cavity and maxillary sinus was extirpated without loss of vision, and a year later the patient was without symptoms. The tumour tissue was Fontana positive, could be bleached, and showed immunoreactivity for S-100, vimentin and HMB 45. Ultrastructurally, the tumour cells, particularly the pigment loaded cells, showed a varying amount of basal lamina at the surface, melanosomes in varying stages of melanization, fine cytoplasmic filaments and micropinocytotic vesicles. Survey of the literature and discussion of the melanogenesis in Schwann's cells are presented.

Adult↗
PubMed1989

Traditional and new treatment strategies for oral squamous cell carcinomas.

308 patients with intraoral carcinomas were treated in the Finsen Institute, Copenhagen, from 1978 to 1982. As primary treatment, 73% of the patients had radiotherapy alone, 5% had operations alone, and 14% had combined treatment. After first recurrences, 45% of 204 patients were operated on. This treatment strategy kept 40% of all 308 patients free of disease for at least 3.5 years or until death. Fifty-eight percent of all 308 patients died of their oral carcinomas. The present study shows that tumor size, lymph node involvement, and total tumor stage are important prognostic factors. Old and new treatment strategies are discussed and more use of operations using modern reconstructive techniques followed by radiotherapy is recommended.

Adult↗
PubMed1989

Otospongiosis and sodium fluoride. A clinical double-blind, placebo-controlled study on sodium fluoride treatment in otospongiosis.

The effect of sodium fluoride treatment in patients with otospongiosis has been evaluated in a prospective clinical double-blind, placebo-controlled study of 95 patients. The results showed a statistically significant greater deterioration of hearing loss in the placebo group than in the group actively treated with 40 mg of sodium fluoride daily. These results support the view that sodium fluoride can change otospongiotic, active lesions to more dense, inactive otosclerotic lesions.

Adult↗
PubMed1989

Etiology of otospongiotic sensorineural losses.

The etiology of otospongiotic-otosclerotic disease is enzymatic; the proteolytic enzymes released by the otospongiotic-otosclerotic foci damage the inner ear and are also the basis of the bony rebuilding of the OW niche leading to stapedial fixation. The trigger may be an autoimmune process due to the reaction of the enchondral otic capsule against the embryonic cartilaginous remnants, genetically determined to be located in the otic capsule and mainly in the fissula antefenestram.

Antibody Formation↗
PubMed1988

Vertigo in postoperative follow-up of otosclerosis.

Causes of vertigo after otosclerosis surgery were studied postoperatively and in long-term follow-up examinations. Pressure and mobility changes in the posterior labyrinth fluids, enzymatic process, and decrease in blood supply at the time of operation appear to be the major causes. Methods of detection, avoiding, and managing vertigo are presented.

Follow-Up Studies↗