Kathryn L. Lovell

Caprine β-Mannosidosis: Clinical and Pathological Features

Beta-mannosidosis, an inherited defect of glycoprotein catabolism associated with deficiency of tissue β-mannosidase and accumulation of Man(β1–4)GlcNAc and Man(β1–4)GlcNAc(β1–4)GlcNAc, appeared in four of 13 offspring of a single pair of clinically normal, related Nubian goats. Neurological examinations revealed that all four affected goats were unable to rise or walk. All had facial dysmorphism, dome-shaped skulls, small palpebral fissures, carpal contractures, hyperextension of the pastern joints, proximal muscle atrophy, intermittent ocular oscillations resembling pendular nystagmus, marked intention tremor, and deafness. With intensive care, three affected kids were hand-reared and then killed at 1, 7, and 21 days of age. Macroscopically, there were paucity of myelin in the cerebral and cerebellar hemispheres and ventricular dilatation. Microscopically, the extent and distribution of cytoplasmic vacuolation, myelin paucity, axonal spheroids, and filamentous expansions were evaluated in the cerebrum, cerebellum, brainstem, spinal cord, and peripheral nerves of the four affected kids and two age-matched, clinically normal kids. Widespread cytoplasmic vacuolation correlated with the previously reported accumulation of oligosaccharides in the brain and kidney and the deficiency of tissue β-mannosidase. β-Mannosidosis, not yet identified in man or other species, is characterized by distinctive neonatal clinical, pathological and biochemical features which differentiate it from the α-mannosidoses and other inherited diseases of glycoprotein catabolism.

Medical students as standardized patients to assess interviewing skills for pain evaluation

The use of medical students as standardized patients in a performance assessment of pain evaluation was studied.

Neuropathology of Bovine β-Mannosidosis

β-Mannosidosis, an inherited defect of glycoprotein catabolism previously identified in goats and humans, has been recently diagnosed in Salers cattle. This disorder is associated with deficiency of lysosomal β-mannosidase and accumulation of oligosaccharides. Analysis of bovine β-mannosidosis neuropathology was initiated to determine whether independently arising gene defects in cattle and goats result in expression of similar lesions. Brain, spinal cord, and selected peripheral nerves from seven affected newborn Salers calves and three normal newborn calves were available for gross, light microscopic, and electron microscopic analysis. Gross examination revealed hydrocephalus of variable severity and myelin deficiency in the cerebral hemispheres, cerebellum, and brainstem. Microscopic examination revealed cytoplasmic vacuolation, myelin deficiency, and axonal spheroids of similar type and distribution to that reported in affected goats. Cytoplasmic vacuolation resulting from lysosomal storage showed consistent variation among cell types. Myelin deficits were more severe in the cerebral hemispheres and cerebellum than in the spinal cord. Axonal spheroids occurred in the cerebrum, brainstem, cerebellum, and trigeminal nerve endings. The presence of similar lesions in bovine and caprine β-mannosidosis supports a direct relationship with the gene defect.

Dysmyelinogenesis in caprine β-mannosidosis: Ultrastructural and morphometric studies in fetal optic nerve

The optic nerves from a goat fetus affected with β‐mannosidosis and a control fetus were analysed morphologically in order to investigate developmental aspects of β‐mannosidosis‐associated myelin deficits. In the affected fetus, the number of myelinated axons per unit area was about 25% of the control values. Histograms of axonal diameter indicated that a greater percentage of the myelinated and unmyelinated axons were of larger caliber in the affected fetus than in the control fetus and that very few small axons were myelinated in the affected animal. The mean values of myelin sheath thickness in the affected and control animals did not differ significantly. Ultrastructural analysis revealed a decreased proportion of oligodendrocytes and an increased proportion of astrocytes in the affected fetus.

Dark avoidance learning and memory disruption by carbon dioxide in cockroaches

Abstract Cockroaches were trained to avoid the dark side of a box using electric shock as a negative reinforcement. The majority of the acquisition of learning occurred within the first minute of training. The reduction in the number of shock bouts initiated during training could be attributed entirely to avoidance learning; no evidence of escape learning was found. There was no decrease in retention of dark avoidance up to 2 hr after training. When carbon dioxide was administered immediately after training, no retention was observed 2 hr later. When CO2 was given 1 hr after training some retention was observed 2 hr after training. These results indicate that memory phases which have different susceptibilities to disruption can be observed in cockroaches.

Development and efficacy of ultrasound-guided fetal fluid aspiration techniques for prenatal diagnosis of caprine β-mannosidosis

Ultrasound-guided fetal fluid sampling was performed on 13 pregnant goats at Days 59 to 65 of gestation to establish safe techniques for accurate sampling and to determine the feasibility of prenatal diagnosis of beta-mannosidosis. Fluids were analyzed for electrolyte and creatinine content to assess accuracy of sampling. Values correlated well with previously reported concentrations for caprine and ovine fetal fluids at the same gestational stage. The single abortion which occurred following ultrasound-guided sampling was correlated with placentome penetration and aspiration of bloody fluids. Thin layer chromatography of amniotic and allantoic fluids was performed to detect oligosaccharides that accumulate in beta-mannosidosis. Abnormal accumulated oligosaccharides were identified in the allantoic but not amniotic fluid from a beta-mannosidase-deficient 62-d-old fetus. Thus, allantocentesis was shown to be an optimal, safe procedure for providing information at this gestational stage to diagnose caprine beta-mannosidosis.

Immunohistochemical Characterization of Rat Central and Peripheral Nerve Tumors Induced by Ethylnitrosourea

Ethylnitrosourea-induced central and peripheral nerve tumors in Sprague-Dawley rats were tested for GFAP (Glial Fibrillary Acidic Protein), S-100 protein, NSE (Neuron Specific Enolase) and Anti-Leu 7 (HNK-1) immunoreactivity utilizing the ABC method (avidin-biotin-complex) for GFAP, S-100 protein and NSE, and the PAP method (peroxidase-antiperoxidase) for Anti-Leu 7. Peripheral nerve neurinomas were consistently positive for S-100 protein and consistently negative for GFAP and Anti-Leu 7. Neurinomas would occasionally exhibit positive staining for NSE (2 of 55 tumors). The staining intensity for S-100 protein varied from strongly positive in differentiated neurinomas to weakly positive in anaplastic tumors. Neoplastic and reactive astrocytes exhibited positive staining for both S-100 protein and GFAP. Variation in the GFAP staining intensity of glial tumors correlated with the degree of differentiation as anaplastic tumors did not stain with the same intensity as their more differentiated counterparts. Oligodendrogliomas exhibited occasional immunoreactivity to S-100 protein (3 of 36 tumors). NSE reactivity in oligodendrogliomas was rarely observed (1 tumor in 36) and immunoreactivity against GFAP or Anti-Leu 7 was consistently absent. Anti-Leu 7 and NSE proved to be of little value in the classification of ENU-induced neural tumors.

Biochemical and histochemical analysis of lysosomal enzyme activities in caprine β-mannosidosis

Goats affected with β-mannosidosis, and autosomal recessive disease of glycoprotein catabolism, have deficient tissue and plasma levels of the lysosomal enzyme β-mannosidase. Pathological characteristics include cytoplasmic vacuolation in the nervous system and viscera, and myelin deficits that demonstrate regional variation. This study was designed to determine the correlation between β-mannosidase activity in normal animals and the severity of lesions in affected goats, and to assess the regional changes in lysosomal enzyme activity in specific regions and cell types in affected animals. Although enzyme activity in normal organs (kidney, thyroid, brain) is correlated in general with the accumulation of uncatabolized substrate and with the extent of vacuolation, this correlation does not extend to assessment of specific region of the central nervous system (CNS). In affected goats, the activities of α-mannosidase, α-fucosidase, and β-hexosaminidase are elevated to a greater extent in all CNS regions than in organs. The results suggest cell-specific, organ-specific, and enzyme-specific regulation of changes in lysosomal enzyme activity in the presence of metabolic perturbations, such as deficiency of β-mannosidase activity.

Otic Pathology of Caprine β-Mannosidosis

Caprine β-mannosidosis is an autosomal recessive defect of glycoprotein catabolism with a deficiency of tissue and plasma β-mannosidase activity and tissue accumulation of oligosaccharides within lysosomes. This rapidly fatal genetic disorder of Nubian goats is expressed at birth by a variety of clinical signs including deafness. Affected goats had folded pinnas, and the tympanic cavity was decreased due to multiple, polypoid projections of bone covered by middle ear mucosa which obstructed the view of the cochlear promontory. Numerous cells of the cochlear duct including mesothelial and epithelial cells of Reissners membrane, mesothelial cells lining the scala tympani, cells of the stria vascularis, numerous supportive cells of the organ of Corti, cochlear hair cells, endothelial cells, perithelial cells, fibroblasts, macrophages, and neurons of the spiral ganglion contained numerous nonstaining intracytoplasmic vacuoles which resulted in distention of affected cells and caused thickening of involved structures. Ultrastructurally, the vacuoles were membrane-bound and consistent with lysosomes. Vacuolated cells were desquamated into the scala vestibuli and scala tympani. This is one of few reports describing light and electron microscopic otic alterations of a storage disease. Goats with β-mannosidosis appear to be good models of hearing loss in patients with storage disease.

Partial External Germinal Layer Regeneration in the Cerebellum Following Methylazoxymethanol Administration: Effects on Purkinje Cell Dendritic Spines

Methylazoxymethanol acetate (MAM) was used to destroy the cerebellar external germinal layer (EGL) in neonatal mice. Partial regeneration of the EGL resulted in regional variations in the number of granule cells present in adult animals. When granule cell depletion was severe, it was accompanied by the formation and persistence of many unattached postsynaptic specializations on Purkinje cell dendritic spines. The number of unattached postsynaptic thickenings seen in areas of moderate granule cell depletion was no greater than seen in control animals. Occasional atypical spine formation was observed in both severely and moderately affected areas. This study further confirms the independence of the postsynaptic specialization in both normal and aberrant cerebella. The correlation between changes revealed at the ultrastructural level and varying degrees of granule cell depletion begins to delineate conditions associated with the development and maintenance of abnormal spines and synapses.