Gangliosides and glycophorin are receptors for wheat germ agglutinin. The competitive binding of these molecules to wheat germ agglutinin is studied by electron spin resonance spectroscopy with spin labels attached to the oligosaccharide chains of gangliosides. Evidence shows that glycophorin is more accessible to wheat germ agglutinin binding than gangliosides. The interactions of gangliosides and glycophorin in liposomes is disrupted on low level binding of WGA.
This case report highlights one of the common but usually unrecognised causes of sinus bradycardia in clinical practice. The reasons for misdiagnosis and/or delay in diagnosis of such a condition is also discussed.
We investigated microwave-stimulated fixation of tissues for transmission electron microscopy using a domestic microwave oven operating at a frequency of 2.45 GHz with an output power of 500W. Microwave-stimulated fixation, in 4% glutaraldehyde, of fresh rat kidney, liver, heart and brain tissues was compared to conventional fixation. Human renal biopsies were similarly studied. Electron microscopy showed excellent ultrastructural preservation comparable to that obtained by conventional fixation. The optimal temperature range for microwave-stimulated fixation was found to lie between 50 degrees C and 55 degrees C. Our results indicate that microwave-stimulated fixation is a rapid and reproducible technique and can be effectively applied to routine diagnostic pathology.
This report details a case of mandibular peripheral ameloblastoma having a clear cell component. The latter consisted of ovoid cells with vacuolated or clear cytoplasm and vesicular or pyknotic nuclei that may be disposed as discrete clusters or show direct transition from typical acanthomatous areas. Comparison of this lesion with other odontogenic and nonodontogenic tumors that contain clear cells is discussed in the context of the differential diagnosis.
Seventeen cases of desmoplastic ameloblastoma were examined immunohistochemically. Immunoperoxidase techniques were applied for detection of keratin, desmin, vimentin and S-100 protein expression in these tumors. The tumor epithelium of desmoplastic ameloblastoma exhibited weak, focal, inconstant keratin staining, weak, variable expression of S-100 protein, desmin immunoreactivity of mild to moderate intensity and vimentin non-reactivity. The pertinent literature on the immunohistochemistry of ameloblastomas is briefly reviewed.
Four cases of either combined occurrence of ameloblastoma and odontogenic keratocyst or a rare keratinising variant of ameloblastoma are presented. The cardinal histomorphologic characteristics are simultaneous occurrence of ameloblastomatous epithelial islands with central keratinisation and multiple keratinising cysts. Immunohistochemically the tumour elements were keratin positive and occasionally S-100 protein and desmin positive. Major differential diagnosis of these neoplasms are discussed.
Granular cell ameloblastoma (GCA) is a well recognized variant of follicular ameloblastoma with extensive granular cell change. In contrast, plexiform granular cell odontogenic tumor (PGCOT) is a rare and recently described lesion characterized histologically by a monophasic plexiform pattern of granular cells. In this paper, two cases of an unusual granular cell odontogenic tumor exhibiting combined features of these two entities are described along with their immunohistochemical characteristics. The granular cells of both the GCA and PGCOT areas showed similar patterns of expression for keratin and S-100, which differed from those of typical ameloblastoma. No reactivity for desmin or vimentin was noted. The histomorphologic and immunohistochemical features of these hybrid tumors suggest that the granular cells present have a common origin, most probably the odontogenic epithelium.
The morphology, incidence and distribution of hyaline cells in ten cases each of pleomorphic adenoma, adenoid cystic carcinoma, adenocarcinoma and mucoepidermoid tumour were studied by conventional light microscopy. Results showed that the hyaline cells were identified in 60% of pleomorphic adenoma and in 20% of mucoepidermoid tumours, but were absent in adenoid cystic carcinoma and adenocarcinoma. Relative area estimation of hyaline cells in pleomorphic adenomas showed that this may range from 2.2% to 30.4% of the total tumour area. The usefulness of the hyaline cell as a diagnostic criteria in distinguishing between some of the salivary gland tumours was also discussed.
Twelve pleomorphic adenomas of minor salivary gland origin were examined for the distribution of S-100 protein, detected using the peroxidase-antiperoxidase (PAP) method. Strong S-100 protein immunoreactivity was noted in areas containing plasmacytoid cells, stellate and spindle cells against a myxochondroid or hyalinous stroma, and solid epithelial areas. Tubular and duct-like structures showed variable stainability. Stromal tissue and normal salivary glands were generally negative for S-100 protein. These findings were compared with those reported elsewhere.
The authors, a psychiatrist and a clinical psychologist, have successfully treated two cases of phobic neurosis by simple behaviour therapy consisting of Jacobson's muscle relaxation technique and systemic desensitisation, at the University Hospital, Kuala Lumpur. The two patients, who were literally housebound because of the unpleasant symptoms of their illness, were able to mobilise themselves again following therapy. The authors feel that general practitioners with some basic training in these methods will be able to bring relief to such afflicted patients. Using the same technique, other conditions such as insomnia, alcoholism and sexual deviations can also be treated.
A case is described of ameloblastoma of maxilla presenting with numerous calcified keratin pearls. The significance of cellular variation in relation to the behavioural potential of the ameloblastoma in general is briefly discussed.
Mucoepidermoid tumours of the minor salivary glands of the tongue are rarely encountered. A case of a high-grade malignant type is reported here. Merits of subdivision of the mucoepidermoid tumour on the basis of its malignant potential are outlined, and variations of histological presentation of the present tumour at its primary and nodal sites are discussed.
The records of the Division of Stomatology, Institute for Medical Research, Kuala Lumpur, Malaysia, were reviewed for the incidence of odontogenic keratocysts of the orthokeratinised variety, during the 20-year-period, 1967 to 1986. Nine cases were found. The clinical, histological and radiological features of these cases are reported. Many features were similar to previous reports of this entity but a peak incidence in the second decade of life, an almost even distribution in the maxilla and mandible, and a distinct predilection for the Chinese were observed. It is suggested that these features may be peculiar to Malaysians.