Biomedical subjects

Nigel H Brookes

Publications and source records attributed to Nigel H Brookes.

4 recordsLinked to original sources

PubMed2006

Clinicopathological features of severe corneal blood staining associated with proliferative diabetic retinopathy.

A 54-year-old man with a history of severe proliferative diabetic retinopathy in both eyes and profound visual impairment presented with severe corneal blood staining in the left eye secondary to a "spontaneous" total hyphaema and raised intraocular pressure in an eye with iris neovascularization. Despite anterior chamber washout, the cornea remained virtually opaque and thickened. The subject subsequently underwent pars plana vitrectomy with endolaser using a temporary keratoprosthesis, insertion of a Morcher iris-surround intraocular lens and penetrating keratoplasty. Histopathology of the excised corneal button revealed fine eosinophilic granules composed of aggregations of haemoglobin and its breakdown products dispersed throughout the stroma, with occasional foci of weakly positive Perl staining for intracellular haemosiderin. Fluorescence confocal microscopy revealed a marked increase in fluorescence throughout the corneal stroma and the basal epithelial layer. This case highlights the microstructural features and aspects of the surgical management of severe corneal blood staining.

Blood↗

PubMed2005

The New Zealand National Eye Bank study 1991-2003: a review of the source and management of corneal tissue.

PURPOSE: To evaluate donor demographics and source, donor tissue processing and storage, biologic contamination, and the utilization and distribution of corneal tissue procured by the New Zealand National Eye Bank. METHODS: As part of a prospective longitudinal study, the electronic records of the NZNEB for the 13-year period 1991-2003 were analyzed for each year with respect to donor demographics, donor source and cause of death, death-to-preservation interval, storage methods, endothelial assessment, biologic contamination, corneal tissue utilization, and distribution. RESULTS: During the study period, 3221 corneas were retrieved from 1628 donors (69.8% male, 30.2% female), with the mean age of donors 59.4 years (SD 18.3 years) and range 4 to 95 years. No significant correlation was identified between donor age group (using 10-year intervals) and the proportion of corneas suitable for transplantation. Donors were procured from the Coroner's service (67.6%), public hospitals, (23.5%) and multiorgan donors (7.1%). The most common causes of donor death were cardiovascular disease, trauma, and cerebrovascular disease. Average storage duration increased from 3.5 to 11.8 days when organ culture replaced hypothermic storage in 1992. Biologic contamination occurred in 5% of all donor corneas. The most common bacterial and fungal isolates were coagulase-negative staphylococci and Candida spp, respectively. A significant decrease in contamination rate over the years of the study was identified. Overall, 79.4% of corneal tissue procured was used for corneal transplantation (75.8% for penetrating keratoplasty, 2.1% for lamellar keratoplasty, and 1.5% for unspecified transplants), and 21.6% was discarded. Most common reasons for discarding tissue were biologic contamination, abnormal serology, and failed endothelial assessment. CONCLUSION: Analysis of the NZNEB database provides valuable information in relation to eye banking and corneal transplantation in New Zealand. Significant trends were identified in donor demographics, donor procurement source, improved donor tissue processing and storage, decreased biologic contamination, and increased utilization of corneal tissue.

Adolescent↗

PubMed2004

Morphological changes in keratoconus: pathology or pathogenesis.

Keratoconus was first discriminated from other corneal ectatic diseases in 1854. Since that time the morphological characteristics of keratoconic progression have been invaluable in the diagnosis of the condition. The key clinical features used to identify keratoconus have remained essentially the same since the introduction of the slit-lamp biomicroscope. Only relatively recently has the development of computerized corneal topography revolutionized the diagnosis of early keratoconus. Analysis of peer-reviewed literature databases revealed a steady chronological increase in pathological research into the progress of keratoconus. This overview describes the recent advances in our understanding of keratoconic pathology and highlights the interactions within the cornea that may be important in the pathogenesis of this condition.

Humans↗

PubMed2003

Confocal imaging of the human keratocyte network using the vital dye 5-chloromethylfluorescein diacetate.

BACKGROUND: The human corneal stroma consists of intercalated layers of collagen and keratocytes. These cells are known to maintain the stroma and aid in repair but it is likely they have other crucial roles throughout the cornea. The complexity of their anatomy is revealed in this study by ex vivo in situ images of the human keratocyte covering a range of ages. METHODS: Human donor corneas of different ages were stained with 5-chloromethylfluorescein diacetate (CMFDA), a dye that is anchored and retained within the cell cytoplasm. The tissue was fixed, sectioned, mounted, and then imaged using a confocal laser scanning microscope at various magnifications and tissue planes. The digital image sets were transferred to multifunction image processing software for analysis and production of 3-D stereo images of keratocyte networks throughout the stroma. RESULTS: High quality images of CMFDA-stained cells revealed differences in the structure and orientation of keratocytes in the anterior, central and posterior stroma, which did not differ throughout the age-range studied. This method reveals very fine cell process ramifications not previously visualized, orientated in lateral and antero-posterior directions, and it confirms the potential for multidirectional communication between keratocyte networks. CONCLUSIONS: This qualitative study found consistency of keratocyte morphology in the normal human cornea throughout life. It confirmed differences in keratocyte anatomy, and the potential for rapid cellular communication by multiple interconnecting processes supporting cohesive keratocyte activity. This high-resolution 3-D microscopic study should assist in identifying gross deviant cellular behaviour in post-surgical and disease states.

Adult↗