Biomedical subjects
Publications and source records attributed to J G Heathcote.
An intralenticular foreign body with associated squamous epithelium was found incidentally at cataract extraction in a 61-year-old man 23 years after a penetrating injury. The squamous epithelium produced no adverse effects. To our knowledge this is the first report of persistence of surface squamous epithelium within the lens.
Incontinentia pigmenti (IP) (Bloch-Sulzberger syndrome) is an X-linked dominant condition usually fatal in males. Shortly after birth affected girls present with a rash followed by pigmentary changes. Abnormalities of the central nervous system and dentition are often present, and ophthalmic problems develop in approximately one-third of patients. The authors present the pathological findings in the skin and eye in a young woman who required enucleation as a result of long-standing retinal detachment and closed-angle glaucoma. A review of published ocular pathology reports indicates that retinal detachment and a fibrovascular retrolental membrane are the commonest intraocular abnormalities in IP. Changes in the retinal pigment epithelium are also prominent, although whether these are primary or secondary remains to be established.
We present a case of partial duplication of the short arm of chromosome 2 (karyotype 46,XX, dup [2p21-2p25]) in a newborn girl. The infant was born at 41 weeks of gestation and died approximately 3 hours after birth. At autopsy the characteristic dysmorphic features (hypertelorism, high, prominent forehead, micrognathia and low-set, malformed ears) and numerous other congenital malformations were observed. Bilateral microcornea with opacities was noted. Histopathological examination of the eyes showed dysgenesis of Bowman's membrane, with glycosaminoglycan deposition and a series of structural anomalies that form part of the anterior segment mesenchymal dysgenesis (ASMD) complex. To our knowledge this is the first case of partial duplication of the short arm of chromosome 2 in which the ocular histopathological features have been studied. Our case provides a further example of the association of ASMD with a chromosomal abnormality.
Collagen shields are a potential delivery system for antifibroblast drugs such as 5-fluorouracil after filtration surgery. To determine whether collagen shields produce histologic evidence of inflammation when implanted subconjunctivally, shields were implanted into four rabbit eyes and six guinea pig eyes and retained for 7 or 14 days. Two rabbit eyes and two guinea pig eyes served as controls. Seven days after implantation in the rabbit eyes foreign-body giant cells were present at the surface of the shield, and early deposition of connective tissue was evident around the shield. The inflammatory response at 14 days was similar but more intense. In the guinea pig eyes the collagen shields induced substantially less inflammation, and there was marked shield degradation at 14 days. The results suggest that the inflammatory response in rabbits may be species specific and that collagen shields may be of value as a drug-delivery system for antifibroblast drugs in other species.
A middle-aged woman developed unilateral, painless proptosis that increased slowly over 1 year. A clinical diagnosis of pleomorphic adenoma of the lacrimal gland was supported by computed tomographic scanning and the tumor was excised. On histological examination the tumor proved to be a benign, myxoid myoepithelioma of spindle-cell type. Although occasionally seen in the salivary glands, to our knowledge, this tumor has not previously been described in the lacrimal gland.
Current classifications of salivary gland tumors separate mucoepidermoid carcinoma from other neoplasms on the basis of a number of histological features, in particular the lack of participation of neoplastic myoepithelial cells. However, ultrastructural examination of low- and intermediate-grade mucoepidermoid carcinomas and pleomorphic adenomas reveals many common organizational and cellular features. Of prime importance is the relationship of intermediate cells to the luminal cells in mucoepidermoid carcinomas, which is remarkably similar to that seen between modified myoepithelial cells and luminal cells in pleomorphic adenomas. The results suggest that intermediate cells of mucoepidermoid carcinoma are the counterpart of the modified myoepithelial cells of pleomorphic adenoma. The generally accepted hypothesis that the former tumor develops from an excretory duct reserve cell, while the latter originates from an intercalated duct stem cell does not seem to be valid; pleomorphic adenoma and mucoepidermoid carcinoma appear to be closely related morphologically.
A 60-year-old woman receiving prednisolone therapy for Sjögren's syndrome presented with corneal perforation. Therapeutic penetrating keratoplasty was performed, but no causative organism was identified. Focal inflammatory infiltrates in both donor and host cornea and anterior uveitis developed postoperatively. Five months later the inflammation rapidly became much worse, with fulminating abscesses, and the eye was eviscerated because of severe endophthalmitis. Nocardia organisms were identified in the cornea, conjunctiva and vitreous by means of acridine orange and modified Ziehl-Neelsen stains. The infection produced both suppurative and granulomatous inflammation. Reexamination of the penetrating keratoplasty specimen with a modified Ziehl-Neelsen stain revealed a few Nocardia organisms, which suggested that infection had occurred at the time of corneal perforation.
A collagen-type pattern of peptide and amino acid spots was obtained when partial hydrolysates of normal human dermis were examined by a specially developed thin-layer chromatographic (TLC) 'finger-printing' technique. The pattern was consistent and independent of age and sex. Two clinically similar cases of osteogenesis imperfecta congenita gave identical patterns which differed in specific regions from those given by their age-matched, normal controls. A single case of osteogenesis imperfecta tarda showed the same overall pattern as the congenita cases. It is concluded that an abnormal amino acid sequence occurs in the collagen molecule of both types of osteogenesis imperfecta.
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The present paper describes a new variation of the "finger printing" technique for examining the primary structure of proteins. It is based on the production of a reproducible, partial acid hydrolysate consisting of amino acids and small peptides which are separated into compact spots by bi-dimensional thin-layer chromatography. The spots are characterized by ther Rf values and colour reactions with a variety of reagents. The method was initially developed for collagen but has been applied to other proteins, with interesting results. It has developed logically from earlier, systematic studies on amino acids and peptides, and holds promise for the comparative investigation of normal and diseased human collagen.
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During the period which has elapsed since the aflatoxins were first isolated, one of the main problems has been the separation of the individual aflatoxins in pure form from aflatoxin-containing extracts. This separation has been best effected by thin-layer chromatography, and in this paper we describe how some of the difficulties may be overcome by using an appropriate combination of solvent system and silica gel preparation. For the examination of aflatoxin-containing extracts from the mycelia of Aspergillus flavus moulds, an initial freeze-drying step has been found to improve appreciably the quality of the chromatograms obtained.
This paper is a continuation of previous work (Parts VI, VIII, and IX) designed to identify small peptides in biological fluids by a combination of ion-exchange and thin-layer chromatography. Several series of peptides, mainly dipeptides, with methionine, phenylalanine, tyrosine, aspartic acid, serine, or glutamic acid as the N-terminal amino acid, have been examined.
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