Kenneth C. Moore

The morphologic characteristics of tumor blood vessels as a marker of tumor progression in primary human uveal melanoma: A matched case-control study☆

Nine morphologic patterns of tumor vessels were identified in eyes removed for ciliary body or choroidal melanoma by the examination of tissue sections stained with fluorescein-conjugated Ulex europaeus I using laser scanning confocal microscopy. This technique also highlights intravascular tumor invasion. Each of these nine morphologic patterns of tumor vessels also may be demonstrated by a modification of the periodic acid-Schiff reaction, viewed with a green narrow band pass filter, but this modified histochemical technique does not accurately identify intravascular tumor invasion. Most tumors have a heterogeneous distribution of vascular patterns. Melanomas in two groups of 20 tumors each were matched by tumor size and location (one group of tumors from patients who survived at least 15 years free of metastatic melanoma after enucleation and one group of tumors from patients who died of metastatic melanoma). A matched case-control analysis indicates that the presence of at least one closed vascular loop in a uveal melanoma is the most significant vascular pattern associated with death from metastatic melanoma after enucleation. Closed loops are associated with other histologic features that are predictive of an unfavorable outcome after enucleation: epithelioid cells and mitotic figures. In this preliminary study the formation of closed vascular loops is a marker of tumor progression in ciliary body and choroidal melanomas.

Ocular pathology of MELAS syndrome with mitochondrial DNA nucleotide 3243 point mutation

PURPOSE The authors describe the clinical, histopathologic, and ultrastructural findings in two eyes obtained at autopsy from a 21-year-old woman with mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS syndrome). METHODS The eyes were obtained immediately after death. The right eye was fixed in 10% neutral-buffered formalin and processed for standard histologic examination. The left eye was fixed in a neutral-buffered 2.5% glutaraldehyde solution and processed for transmission electron microscopic examination. The authors compared the histologic and ultrastructural findings with the clinical features recorded photographically. RESULTS The main clinical ophthalmologic features were bilateral ptosis, chronic external ophthalmoplegia, diffuse choroidal atrophy, atypical pigmentary retinopathy with macular involvement, and patchy atrophy of the iris stroma. Molecular genetic analysis detected a tRNA Leu (UUR) point mutation at position 3243 of mitochondrial DNA (MELAS genotype). Results of histologic and ultrastructural examination showed ragged-red fibers in the rectus muscles, degeneration of photoreceptor outer segments in the macula, hyperpigmentation and atrophy of the retinal pigment epithelium of the macula, atrophy of the iris stroma, early posterior subcapsular cataract, and optic atrophy. The retinal pigment epithelium, inner segments of the photoreceptors, smooth muscle cells of the choroidal and retinal vessels, the dilator and sphincter muscle of the iris, cornea, lens epithelium, and ciliary epithelium all contained many, often enlarged, structurally abnormal mitochondria with occasional paracrystalline inclusions and circular cristae. CONCLUSIONS The MELAS-associated mitochondrial DNA nucleotide 3243 point mutation can cause a spectrum of ocular signs and symptoms that may be dependent on the patients age and the amount of mutant mitochondrial DNA in the tissue. MELAS syndrome should be considered in the differential diagnosis of bilateral ptosis, external ophthalmoplegia, and atypical pigmentary retinopathy with macular involvement.

Diabetic Peripheral Neuropathies: A Morphometric Overview

La diabetes es considerada hoy una de las principales amenazas para la salud humana en el siglo 21 y muchos investigadores se dedican a investigar la fisiopatologia de la enfermedad, con otras visiones sobre el manejo de sus principales complicaciones. Dado que la comprension de la fisiopatologia de las principales complicaciones de la diabetes y sus procesos subyacentes es obligatorio, modelos experimentales de la enfermedad pueden ser utiles ya que permiten el reconocimiento de los primeros mecanismos implicados en las complicaciones a largo plazo de la diabetes. El compromiso de los nervios perifericos es muy frecuente en la diabetes mellitus y se ha documentado que un tercio de los pacientes diabeticos tiene neuropatia periferica. La prevalencia es desconocida y los informes varian de 10% a 90% en los pacientes diabeticos, en funcion de los criterios y metodos utilizados para definir la neuropatia. En esta revision, se presentan los modelos experimentales mas comunes de diabetes y se discuten los hallazgos patologicos en los principales nervios perifericos. Ademas, se destacan las visiones presentadas por la morfometria de la investigacion la neuropatia diabetica.

Relative Importance of Quantifying Area and Vascular Patterns in Uveal Melanomas

PURPOSE To test whether the cross-sectional area of choroidal and ciliary body melanomas and quantification of microcirculatory networks and parallel vessels with cross-linking are features associated with death from metastatic melanoma, and to compare new with conventional histologic prognostic features. METHODS The cross-sectional area of 234 ciliary body or choroidal melanomas was measured from digitized images of histologic sections. The percentage of cross-sectional area occupied by two microcirculatory patterns-networks and parallel vessels with cross-linking-was calculated for the 152 tumors containing at least one focus of either pattern. Kaplan-Meier survival curves were generated based on cross-sectional and percentage of cross-sectional areas of these patterns. Cox proportional hazard regression methods related time to death from melanoma with sets of predictor variables. For each model, percent variation explained was computed. RESULTS Patient survival differs significantly when tumors are classified based on cross-sectional area: small (<16 mm2), medium (> or =16 mm2 but <61.4 mm2), and large (> or =61.4 mm2). Patients with tumors containing networks and parallel vessels with cross-linking microcirculation patterns that occupy 2% of cross-sectional area have a significantly worse prognosis than do those patients with tumors containing a smaller percentage of these patterns. CONCLUSIONS Quantifying cross-sectional tumor area and the percentage area occupied by networks and parallel vessels with cross-linking microcirculatory patterns in ciliary body and cho. roidal melanomas provides significant prognostic information. Compared with more conventional prognostic characteristics, the most dramatic increase in prognostic information is provided by determination of the presence or absence of microvascular patterns.

Pressure-induced regression of oral apparatus microtubules in synchronized Tetrahymena.

The effect of pressure treatment on the later stages of oral morphogenesis was studied in synchronized Tetrahymena pyriformis GL-C. Prior to the end of the treatment, there were alterations in the oral cilia and basal bodies, as well as other microtubular structures. Microtubules in the nondeveloping oral regions were insensitive to the pressure treatment. Cells examined after the release of pressure contained basal bodies and denuded cilia within their cytoplasm. The ciliary doublet microtubules regressed in a definite sequence: (1) the outer wall of the B tubule, (2) the remainder of the B tubule, and (3) the A tubule. This regression was asynchronous among doublets and occurred independently of the state of regression of the central microtubules. The regression of basal body microtubules occurred initially with the loss of the circular arrangement of the triplet microtubules, and then these microtubules disintegrated along all parts of the triplet. Regressing oral structures were never observed to be contained within autophagic vacuoles. The possible significance for the lack of autophagy associated with oral resorption is discussed.

Ultrastructural Morphology and Morphometry of Phrenic Nerve in Rats

Despite numerous literature reports on the morphometry of the myelinated fibers of phrenic nerves in rats, a systematic study of the longitudinal and lateral symmetry of the unmyelinated fibers morphometry is not available. In this study, we have undertaken ultrastructural and morphometric studies of the phrenic nerve in adult rats, assessing two different levels (proximal and distal) from both right and left sides. Phrenic nerves of adult male Wistar rats were prepared for epoxy resin embedding and transmission electron microscopy. Morphometric analysis was performed with the aid of computer software, which took into consideration the unmyelinated fiber number, density, area, and diameter, as well as ratio between myelinated and unmyelinated fibers, and the percentage of the fascicular area occupied by the myelinated and unmyelinated fibers. Comparison of data from proximal and distal segments on the same side and from the same levels between sides was performed. Differences were considered significant when P < 0.05. The most important finding is that morphometric parameters of the phrenic nerve unmyelinated fibers in adult rats are both longitudinally and laterally symmetric. This study adds important morphometric information about the unmyelinated fibers of the phrenic nerves in adult rats for proximal and distal levels on both sides of the animal. Anat Rec 2009.

Transmission Electron Microscopy Studies of the Vestibulocochlear Nerve in Chronic Diabetic Rats

Se ha descrito ampliamente en la literatura que los pacientes diabeticos presentan discapacidad auditiva. En estos pacientes, a pesar de las alteraciones histologicas de las estructuras del oido interno, asi como en modelos experimentales de diabetes, que mejoran nuestro conocimiento, la evaluacion histologica del nervio vestibulococlear no ha sido realizada. Se describen y comparan las alteraciones ultraestructurales entre un nervio espinal y uno craneal en ratas con diabetes cronica inducida. Fueron utilizadas 12 ratas Wistar machos, de 42 dias de edad, alimentadas con dieta estandar. Los animales diabeticos inducidos (n = 6) se mantuvieron en ayuno por 12 horas antes de ser inyectados por via intraperitoneal con estreptozotocina (STZ - 60mg/kg) en una sola dosis. Los animales control (n = 6) solo recibieron inyeccion de 0.01 mol/l buffer, citrato pH 4,5. Diez semanas despues de la inyeccion de STZ, los animales fueron perfundidos intracardiacamente con solucion de Karnovsky. Los nervios vestibulococlear derecho e izquierdo fueron disecados y procesados histologicamente para ser incluidos en resina epoxy. Las muestras fueron estudiadas con microscopio electronico de transmision. Fueron observadas facilmente, grandes fibras mielinizadas con signos morfologicos de atrofia axonal en los nervios vestibulococlear. Estos resultados sugieren que la diabetes cronica inducida por STZ en ratas causo alteraciones en las fibras mielinicas y celulas del neurilema, compatible, con los signos y sintomas clasicos de la diabetes. Alteraciones morfologicas del nervio vestibulococlear en la diabetes son descritas por primera vez, lo que aporta informacion para una mejor comprension de por que hay cambios en la audicion en los pacientes diabeticos.

Applications of Microscopy to Genetic Therapy of Cystic Fibrosis and Other Human Diseases

Gene therapy has become an extremely important and active field of biomedical research. Microscopy is an integral component of this effort. This chapter presents an overview of imaging techniques used in our facility in support of cystic fibrosis gene therapy research. Instrumentation used in these studies includes light and confocal microscopy, transmission electron microscopy, and scanning electron microscopy. Techniques outlined include negative staining, cryo-electron microscopy, three-dimentional reconstruction, enzyme cytochemistry, immunocytochemistry, and fluorescence imaging.