Biomedical subjects
Publications and source records attributed to M R Conlon.
Infectious dacryoadenitis is a rare condition. A case of Pseudomonas dacryoadenitis has not been reported previously. We treated a patient with Pseudomonas dacryoadenitis secondary to obstruction from a lacrimal gland ductule stone. Histologically, the calculus contained hairs.
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We designed an animal model using sheep to evaluate three methods of canalicular reconstruction after laceration: direct sutured reapposition of the canaliculus without silicone intubation (4 eyelids), silicone intubation of the canalicular system without mucosal anastomosis (14 lids) and silicone intubation with mucosal anastomosis (10 lids). We also wished to determine the appropriate time of silicone tube removal. In the canaliculi repaired using silicone intubation the tubes were removed at 4, 8 or 12 weeks. Patency of the canalicular system was assessed at 16 weeks by probing. Sections of eyelid tissue were examined histopathologically to confirm patency and to compare the tissue alteration caused by the various methods of repair. We found that silicone intubation was necessary to reestablish patency of the canaliculus and that silicone intubation with and intubation without mucosal anastomosis were equally efficacious in restoring canalicular patency. The optimum time for removal of the tube was 12 weeks. Histopathologically, all canaliculi found to be patent by probing demonstrated mucosal continuity along the canalicular lumen.
Intraocular BB pellet injuries are a devastating form of ocular trauma with a poor prognosis. The penetration of the eye by the pellet causes a marked disruption of the intraocular contents that in most cases leads to enucleation. We describe a 15-year-old boy who suffered a penetrating intraocular BB pellet injury to his right eye and underwent primary repair of the injury followed by secondary vitrectomy and prophylactic panretinal photocoagulation. The postoperative management was complicated by a retinal detachment; however, this responded to a scleral buckling procedure. Eighteen months after the injury the acuity in the affected eye was 20/30 with a contact lens. To our knowledge this is the first case in which useful vision has been recovered in this type of injury.
Obtaining vitreous fluid by means of vitrectomy frequently results in a specimen that is difficult to assess cytologically. We devised an experimental model to examine the effect of the vitrector on human leukemic cancer (HL60) cells in suspension and to evaluate the cytopreparatory techniques of membrane filtration and cytocentrifugation. Eighteen 3-mL specimens of cells at concentrations ranging from 1 to 9 x 10(5)/mL were vitrectomized, and eighteen 3-mL control samples matched for cell concentration were obtained atraumatically. No significant difference in cell loss, as determined by means of staining with nigrosin vital dye, was found at any cell concentration between the vitrectomized and control specimens. The specimens were then processed cytologically. On cytologic assessment it was not possible to distinguish the vitrectomized and control specimens. A higher degree of cell preservation was noted at higher cell concentrations regardless of the cytopreparatory technique, but at lower concentrations membrane filtration resulted in a higher proportion of cytologically assessable specimens than did cytocentrifugation (42% vs. 22%). The results suggest that the vitrector causes minimal cellular damage and that to obtain optimal results both cytopreparatory techniques should be used with all vitrectomy specimens.
Primary localized amyloidosis causing bilateral lacrimal enlargement is rare. The pathogenesis of amyloid deposition within the orbit and other body tissues has not been fully elucidated. The authors report the case of a 72-year-old woman who presented with bilateral lacrimal gland enlargement secondary to amyloid infiltration. The chemical nature of the deposit was characterized using light microscopy, immunohistochemistry, and immunoelectron microscopy. The primary (immunocytic) nature of the amyloid was confirmed by immunohistochemistry demonstrating the presence of monoclonal lambda light chains in the amyloid deposits and in the plasma cells. Using immunoelectron microscopy, amyloid deposits were seen containing lambda light chains in macrophages. It has been postulated that the macrophage has a role in amyloid deposition. The authors believe this to be the first published report of immunoelectron microscopy use in orbital amyloidosis, and that this technique has helped further their understanding of the nature and pathogenesis of this condition.
A previously healthy 33-year-old woman presented with decreased vision and pain in her left eye. Funduscopic examination revealed a mass in the posterior pole of the eye, and chest radiography showed a lesion in the lower lobe of her left lung. The eye became painful and blind over 12 days and was enucleated. The tumour had the typical histopathological and immunohistochemical features of choriocarcinoma: sheets of cytotrophoblasts with pleomorphic nuclei and lacy cytoplasm intermingled with multinucleated syncytiotrophoblasts. The neoplastic cells stained positively for cytokeratin and the beta subunit of human chorionic gonadotropin (beta-HCG). The serum beta-HCG level was markedly elevated, at 82,000 (normally less than 5) IU/L. The patient was treated with combination chemotherapy, and normal serum beta-HCG levels were obtained. Thirty months after presentation the serum beta-HCG level was normal and there had been no clinical evidence of recurrence. To our knowledge this is the second case of metastatic choriocarcinoma in the eye in which the ocular tumour caused the presenting symptom.
Karyotyping and polymorphisms within the DCC (deleted in colon cancer) locus (18q21) were used to analyze loss of chromosome 18 in squamous cell carcinomas (SCC). Tumors from 26 patients (including 7 for whom matched tumor and normal DNA samples were available) were examined for heterozygosity within DCC. Of the seven normal-tumor combinations, four were informative. Two of these had loss of heterozygosity (LOH) at DCC. For 19 SCC tumor cultures normal tissue was not available. These were scored only as homozygous or heterozygous. The majority were homozygous. Only 3/19 (15%) were heterozygous. In contrast, in a panel of normal blood samples the majority, 11/16 (69%), were heterozygous. Allelic zygosity was concordant with the chromosome 18 content in the 16 tumors that were also karyotyped. Tumors from 40 patients, 37 that were karyotyped and three that were informative at the DCC locus, were assessed for loss of chromosome 18 and patient survival. Loss of part or all of chromosome 18 occurred in tumors from 25. Twenty-seven of the 40 patients have died and 13 are alive. There was strong association between loss of 18 and overall survival. Of those who are alive only 5/13 (38%) had loss of 18, whereas among those who have died 20/27 (74%) had loss of 18. By chi 2 analysis the association of loss of 18 and death from cancer was significant (p > 0.01). The high frequency of chromosome 18 loss in SCC suggests that this region contains one or more tumor suppressor genes important in the clinical behavior of SCC. DCC is one candidate, but other regions of loss not including the DCC locus indicate that chromosome 18 probably contains more than one tumor suppressor locus. Prospective studies of chromosome 18 loss as a single prognostic indicator are strongly indicated in this tumor type since loss in early stage tumors might indicate a need for more aggressive therapy than would be given on the basis of staging alone.