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41.
A woman with severe cicatricial conjunctival changes secondary to allopurinol-induced Stevens-Johnson syndrome developed bilateral palpebral conjunctival cysts. Pathologic examination of these lesions revealed respiratory-like pseudostratified ciliated epithelium in the walls of several cysts of one eye. To our knowledge, this is the first report of this phenomenon. 相似文献
42.
A T Yachnis L B Rorke J A Biegel G Perilongo R A Zimmerman L N Sutton 《The American journal of surgical pathology》1992,16(10):998-1006
We report an unusual large, multicystic, posterior fossa neuroepithelial neoplasm involving the cerebellum, brain-stem, and quadrigeminal cistern of a 9-month-old girl. The neoplasm consisted of variably sized, sharply demarcated nests of small cells with a high nuclear-cytoplasmic ratio and moderately basophilic nuclei, embedded in a desmoplastic, immature-appearing, mesenchymal stroma. The nests contained mitoses but none were seen in the stroma. Glial fibrillary acidic protein (GFAP), neurofilament protein, synaptophysin, and cytokeratin (AE-1) were expressed in the nests. Mesenchymal cells were negative for neural markers but positive for vimentin and desmin. The neoplasm was interpreted as a mixed mesenchymal and primitive neuroectodermal tumor (PNET) with histologic features reminiscent of a recently described intraabdominal desmoplastic small cell tumor. The tumor responded poorly to chemotherapy and a second operation was performed 1 year later. The second specimen bore no resemblance to the original and consisted of epithelial-like nests and clusters of neoplastic cells frequently interrupted by sinusoidal vessels. Tumor cells had medium-sized vesicular nuclei with small nucleoli, and a granular cytoplasm. Occasional less cellular islands of neuropil-like tissue contained larger cells having eccentric, vesicular nuclei with prominent nucleoli and abundant pink cytoplasm. Mitoses were not conspicuous. Many cells expressed synaptophysin, neurofilament protein, and GFAP. Neurofilament protein was strongly positive in the larger, neuron-like cells and synaptophysin stained the neuropil-like areas strongly but was less prominent in the neuronal perikarya. Unexpectedly, the neuropil-like areas expressed epithelial membrane antigen, whereas the neuronal cells were negative for chromogranin A. The peculiar histologic picture, combination of phenotypic markers, and remarkable biologic behavior of this unusual tumor defies classification according to existing nomenclature and exemplifies the broad range of phenotypes expressed by primitive neuro-epithelial neoplasms. 相似文献
43.
James E. Salter Jr. Donald Gibson Nelson G. Ord ez Bruce Mackay 《Ultrastructural pathology》1995,19(4):305-310
A 7-cm anterior mediastinal tumor in an 80-year-old woman was found by light and electron microscopy to be a neuroblastoma. Immunoreactivity for neuron-specific enolase, synaptophysin, and chromogranin supported the diagnosis. Neuroblastoma is an uncommon tumor in adults and we are not aware of a previous report of such a tumor in a patient of this age. 相似文献
44.
45.
Donald R. Vandevanter John C.-H. Tseng Getachew Yirdaw 《Genes, chromosomes & cancer》1995,12(4):262-271
Gene amplification allows transformed cells to overexpress specific genes and gain a survival advantage. For this reason, cloning and characterization of amplified genes can improve our understanding of the biology of transformed cells. The techniques of in-gel renaturation and chromosome microdissection can enrich for amplified DNA sequences, but both are labor intensive and have other drawbacks. We have developed an alternative strategy of enriching for amplified DNA sequences that involves two-directional agarose gel electrophoresis of extrachromosomal circular DNA. Extrachromosomal circles can be detected with repetitive DNA probes and can be used to produce DNA probes suitable for fluorescence in situ hybridization for location of genomic origin. The ability to enrich for amplified DNA without specialized equipment or transformed cell metaphases should prove useful in the search for new genes which are important in tumor cell progression. 相似文献
46.
L. T. Bilaniuk P. T. Molloy R. A. Zimmerman P. C. Phillips S. N. Vaughan G. T. Liu L. N. Sutton M. Needle 《Neuroradiology》1997,39(9):642-653
We describe the clinical and imaging findings of brain stem tumours in patients with neurofibromatosis type 1 (NF1). The
NF1 patients imaged between January 1984 and January 1996 were reviewed and 25 patients were identified with a brain stem
tumour. Clinical, radiographical and pathological results were obtained by review of records and images. Brain stem tumour
identification occurred much later than the clinical diagnosis of NF1. Medullary enlargement was most frequent (68 %), followed
by pontine (52 %) and midbrain enlargement (44 %). Patients were further subdivided into those with diffuse (12 patients)
and those with focal (13 patients) tumours. Treatment for hydrocephalus was required in 67 % of the first group and only 15
% of the second group. Surgery was performed in four patients and revealed fibrillary astrocytomas, one of which progressed
to an anaplastic astrocytoma. In 40 % of patients both brain stem and optic pathway tumours were present. The biological behaviour
of brain stem tumours in NF1 is unknown. Diffuse tumours in the patients with NF1 appear to have a much more favourable prognosis
than patients with similar tumours without neurofibromatosis type 1.
Received: 21 November 1996 Accepted: 22 December 1996 相似文献
47.
J W Bailet M C Zimmerman D P Arnstein J S Wollman R A Mickel 《Archives of otolaryngology--head & neck surgery》1992,118(11):1245-1249
Sebaceous carcinoma is uncommon, with fewer than 400 cases reported. Usually, lesions arise in the meibomian glands of the eyelid; however, extraocular lesions within the head and neck have been reported. Regardless of the location, sebaceous malignancies must be considered aggressive neoplasms with a potential for regional and distant metastasis. Diagnosis may be difficult, given the low incidence and inconsistencies in histopathologic classification. Recently, needle aspiration cytologic characteristics have been delineated, with this procedure becoming increasingly useful in establishing the diagnosis. Treatment requires wide surgical excision with removal of involved regional lymph nodes. Opinions are divided regarding the use of postoperative irradiation or chemotherapy. Records of all patients with sebaceous carcinoma of the head and neck treated at UCLA Medical Center, Los Angeles, over the last 35 years were reviewed. The clinical and pathologic features are discussed, and the literature is summarized. 相似文献
48.
49.
R W Lash R K Desai C A Zimmerman M R Flack T Yoshida F E Wondisford B D Weintraub 《Journal of endocrinological investigation》1992,15(4):255-263
In recent studies, site-directed mutagenesis has been used to alter the tripeptide glycosylation recognition sequences of glycoprotein hormone subunits, thereby affecting their structure and function. However, it is not known whether these effects result from changes in glycosylation status, amino acid sequence, or both. We therefore studied the synthesis of wild-type and mutant recombinant human thyrotropins produced by transient transfection of a human cell line. Mutating the TSH-beta subunit glycosylation recognition sequence, Asn-Thr-Thr (codons 23-25), to either Gln-Thr-Thr or Asn-Thr-Tyr abolished subunit glycosylation, as demonstrated by the inability to incorporate 3H-carbohydrates. However, a third mutation (Asn-Thr-Ser) contained an intact glycosylation recognition sequence site, and was shown to retain glycosylation. The mutations that abolished TSH-beta subunit glycosylation resulted in greater than 90% decreases in TSH synthesis. However, the glycosylation recognition sequence mutant that retained beta subunit glycosylation exhibited a 70% decrease in TSH production. These decreases were not attributable to the intracellular accumulation of TSH or its free beta subunit. We also engineered two TSH-beta subunit mutations that did not alter the glycosylation recognition sequence. A glycine to arginine mutation adjacent to the glycosylation recognition sequence, in a region thought to be critical for heterodimer formation, abolished TSH production. In contrast, shortening the TSH-beta subunit carboxyterminus by six amino acids increased TSH synthesis.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
50.
Donald M. Campbell Gerald I. Forbes 《International journal of environmental health research》1994,4(2):86-92
The prevention of the spread of disease by drinking water relies on a tripartate arrangement among the supplier, the regulator and their medical advisers. This paper describes the role of Public Health Medicine in Scotland in preventing a ‘significant risk to health’ from potable water. The legislative framework is highlighted. The rationale of water monitoring is examined and the role of Consultant in Public Health Medicine. The concept of Significant Medical Risk Values is introduced and their derivation, uses, and levels presented. 相似文献