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Mannosidosis is a rare inborn error of metabolism characterized by deficiency of the lysosomal enzyme alpha-mannosidase and widespread storage of complex carbohydrate, which is enriched in mannose. Two affected unrelated males, aged 6 and 26 years, are reported. Both had a nonprogressive encephalopathy with moderately severe mental retardation. The older patient showed several unique features, including massive gingival hyperplasia associated with histiocytes containing large amounts of a material with the staining characteristics of glycoprotein. The best determinant of mannose storage proved to be the ratio of mannose to other carbohydrates in urinary polysaccharides. The enzyme deficiency in this disease is most convincingly demonstrated at pH values below 4.0. The ability of zinc to activate the mutant enzyme in vitro offers a possible mode of therapy for this disease. Retarded individuals with a Hurler-like appearance and gum hyperplasia of unknown cause should be screened for alpha-mannosidase deficiency.

A sibship originally reported by Friedman and Roy as showing severe mental retardation, strabismus, hyperactive tendon reflexes, lalling speech, and foot deformities was restudied. Three major additional findings were noted. The cerebrospinal fluid protein concentration was increased two to three times above normal in four siblings who were available for study. Radiographs of cranial structures in three siblings showed identical pathologic intracranial calcifications which correspond in distribution to the choroid plexus. The choroid plexus was not demonstrable in one patient when radiolabeled 99m-Tc-pertechnetate was injected without perchlorate. Neuropathologic findings in one sibling included small subcortical heterotopias and atrophy of the choroid plexus with encasement by glial fibrils. These findings denote a new heredofamilial neurologic syndrome associated with mental retardation and a disorder of choroid plexus.

Two infants with the cerebro-hepato-renal syndrome (Zellweger's disease) exhibited cholestasis and progressive liver damage. Because abnormalities of mitochondrial structure and function have been reported in this condition, we examined the bile acids for evidence of defects in the mitochondrial phase of bile acid synthesis, namely, oxidation of the cholesterol side chain to form C-24 bile acids. The presence of increased amounts of the C-27 bile acid intermediates (trihydroxycoprostanic acid, varanic acid, and dihydroxycoprostanic acid) were noted and identified by gas-liquid chromatography-mass spectrosocopy confirming that a defect in the mitochondrial pathways for bile acid side chain cleavage is involved in this entity. The clinical course, liver histopathology, and hepatocyte ultrastructural abnormalities suggest that these bile acids may reflect an underlying mitochondrial dysfunction in this disease and possibly may contribute to the progressive hepatic lobular fibrosis observed in these patients.

We examined the distribution and density of N-methyl-D-aspartate (NMDA) displaceable L-[3H]glutamate binding sites in human hippocampal samples obtained postmortem from Alzheimer's disease (AD) patients and from age-matched controls. Binding to NMDA receptors was stable for at least 72 h postmortem, and the pharmacological profile corresponded to that described using electrophysiology. NMDA receptors were concentrated in the terminal fields of major hippocampal pathways including the perforant path, Schaffer collaterals and the hippocampal output to the subiculum, all of which are proposed to use an excitatory amino acid transmitter. Little if any change in hippocampal receptor density was observed in AD patients compared to age-matched controls except in one case where major hippocampal cell loss occurred. The distribution of NMDA receptors did, however, correspond to the predilection for neuritic plaques and neurofibrillary tangles in hippocampal subfields.

A 13 1/2-year-old child died with vitamin B6-dependent seizures in progress. Microscopic findings in brain included an abnormally sparse quantity of central myelinated fibers in the cerebral hemispheres. Glutamic acid concentrations were elevated and GABA concentrations reduced in the frontal and occipital cortices but not in the spinal cord. All other amino acid concentrations were normal, except for increased cystathionine in the occipital cortex. Pyridoxal-5-phosphate (PLP) was reduced in the frontal cortex. Glutamic acid decarboxylase activity comparable to that of controls was detected when the PLP concentration was greater than 0.05 mM. These findings suggest that pyridoxine-dependent seizures in man are associated with reduced GABA concentrations in the brain and with diminished central white matter structures.

Two case studies are presented describing the use of response-contingent taste-aversion procedures to treat chronic ruminative vomiting of profoundly retarded children. Each treatment programme was designed to be carried out by para-professional staff in an institutional setting. Each programme eliminated rumination, with effects maintained one to nine months following treatment. For one subject who exhibited major weight-loss prior to intervention, substantial weight-gain was also demonstrated.

The principal neuropathologic abnormality observed in three autopsy cases of Menkes steely hair syndrome was widespread nerve cell loss and gliosis, especially severe in the cerebral and cerebellar cortex and in the relay nuclei of the thalamus. Granular stellate cells of neocortical layer IV and the granule cells of the cerebellum are cell classes which were particularly severely depopulated. The degree of reduction of myelinated axons is consistent with axonal degeneration secondary to nerve cell loss. There are also prominent abnormalities in the patterns of dendritic arborization of surviving cortical pyramids and cerebellar Purkinje cells as seen in Golgi impregnations. The deviant neuronal forms are probably due, in part, to failure of innervation by afferent fiber systems during the fetal as well as postnatal epochs.

The present work investigated the light and electron microscopic changes in hypertrophied gingiva in a patient with mannosidosis. The biopsy specimens studied covered a period of 20 months; biopsy specimens were taken before and after a therapeutic trial with oral and local zinc sulfate. The intensity of the disease was progressive, in spite of the zinc, and was characterized by marked hyperplasia of the epithelium and severe inflammation of the stroma. Many of the cells in the inflammatory infiltrate, as well as cells indigenous to the gingiva, showed a striking vacuolation of their cytoplasm. Histiocytes were most numerous and also were most heavily vacuolated, but fibroblasts, endothelial cells, plasma cells, and epithelial cells also manifested the vacuolar change. In the histiocytes, the vacuoles occupied most of the cytoplasm, ranged widely in size, and were contiguous, molded, and intercommunicating. The vacuoles were bound by a single membrane and were filled predominantly by a finely granular material of medium density but also by varying amounts of coarser, darker granules, fragmented membranes, myelin-like figures, lipid droplets, and small vesicles. The vacuoles were interpreted as being consistent with secondary lysosomes that contained excessively stored substrate, similar to what has been observed in the mucopolysaccharidoses, in which the vacuoles have also been demonstrated histochemically and cytochemically to contain acid phosphatase, a known lysosomal marker.

This review has been directed towards those aspects of DS which bear upon pathological aging. Clinical dementia in DS has heretofore been studied largely by retrospective methods with variable findings. A prospective study utilizing techniques designed to measure cognitive performance in a poorly verbal, retarded population is badly needed. There is definitive evidence for Alzheimer's disease changes in the brains of DS patients with some suggestion of altered topography compared to the general population. Immunological studies have established a T-cell deficiency in DS that may be linked to precocious aging of thymic-dependent processes. Both antiviral and nonantiviral effects of interferon are accentuated in cell culture systems utilizing DS tissue, presumably as a consequence of the localization of the interferon gene(s) on chromosome 21. Multiple endocrine studies confirm the high frequency of autoimmune disease, an abnormality that may be related to the problems of immune surveillance in DS. Precocious aging has been noted in regards to measures of skin elasticity, fenestration of cardiac valves, and premature cataracts. The 21st chromosome has been implicated in the elevated activity of superoxide dismutase, a finding of significance in regard to potential intracellular damage from increased levels of peroxide. Several studies have suggested a compensatory increase in glutathione peroxidase.

Retinoic acid, an analogue of vitamin A, is known to be teratogenic in laboratory animals and has recently been implicated in a few clinical case reports. To study the human teratogenicity of this agent, we investigated 154 human pregnancies with fetal exposure to isotretinoin, a retinoid prescribed for severe recalcitrant cystic acne. The outcomes were 95 elective abortions, 26 infants without major malformations, 12 spontaneous abortions, and 21 malformed infants. A subset of 36 of the 154 pregnancies was observed prospectively. The outcomes in this cohort were 8 spontaneous abortions, 23 normal infants, and 5 malformed infants. Exposure to isotretinoin was associated with an unusually high relative risk for a group of selected major malformations (relative risk = 25.6; 95 per cent confidence interval, 11.4 to 57.5). Among the 21 malformed infants we found a characteristic pattern of malformation involving craniofacial, cardiac, thymic, and central nervous system structures. The malformations included microtia/anotia (15 infants), micrognathia (6), cleft palate (3), conotruncal heart defects and aortic-arch abnormalities (8), thymic defects (7), retinal or optic-nerve abnormalities (4), and central nervous system malformations (18). The pattern of malformation closely resembled that produced in animal studies of retinoid teratogenesis. It is possible that a major mechanism of isotretinoin teratogenesis is a deleterious effect on cephalic neural-crest cell activity that results in the observed craniofacial, cardiac, and thymic malformations.

A cerebral biopsy specimen from a 4-year-old girl with a moderately advanced stage of the late infantile form of neuronal ceroid-lipofuscinosis was observed in routine cell and fiber stains and in Golgi and electronmicroscopic preparations. There was no evidence of neuronal degeneration or loss. Golgi impregnations identified a fusiform enlargement of proximal axon segments of most pyramidal neurons and some polymorphic neurons but not of other cortical neuronal classes. Typical curvilinear inclusions were found in all cells and appeared to be impacted within the dilated proximal axon segments of pyramidal neurons. The numbers of type II synapses on the axon hillock and dilated proximal axon segments of pyramidal neurons were much reduced, whereas type I synapses remained abundant in the neuropil.

Copper (Cu) metabolism was selectively studied in seven infants with Menke's steely-hair syndrome (SHS). A daily oral regimen of CuSO4 (584 microgram Cu/kg) and L-histidine (100 mg/kg) in three infants produced an increase in serum Cu concentrations ranging from 33-95% of normal, but without the formation of ceruloplasmin. Cohn serum protein fractionation after oral Cu/L-histidine loading showed a disproportionate accumulation of Cu in the albumin fraction (V). The electron spin resonance spectrum of fraction V showed a heightened signal for the SHS patients, suggesting that an increased concentration of a radical Cu species is present after oral loading. The Sephadex G-150 chromatographic profile of serum fraction V in SHS did not differ significantly from controls. These results suggest that, in SHS, Cu absorbed in the presence of L-histidine is in an abnormal complex involving albumin, which does not allow for holoceruloplasmin biosynthesis. Cu and ceruloplasmin concentrations in the cord blood specimen of an infant who went on to develop SHS were normal, a finding which may account for the transient period of seemingly normal development after birth in SHS patients. An almost 6-fold difference in mean Cu concentration was observed in SHS fibroblasts compared to controls. Fibroblast Cu concentration was elevated in one to two possible maternal heterozygotes, a finding which may permit diagnosis of the carrier state for some SHS heterozygotes.

Two markers of neuronal plasticity were used to compare the response of the human central nervous system to neuronal loss resulting from Alzheimer's disease with the response of rats to a similar neuronal loss induced by lesions. In rats that had received lesions of the entorhinal cortex, axon sprouting of commissural and associational fibers into the denervated molecular layer of the dentate gyrus was paralleled by a spread in the distribution of tritiated kainic acid-binding sites. A similar expansion of kainic acid receptor distribution was observed in hippocampal samples obtained postmortem from patients with Alzheimer's disease. An enhancement of acetylcholinesterase activity in the dentate gyrus molecular layer, indicative of septal afferent sprouting, was also observed in those patients with a minimal loss of cholinergic neurons. These results are evidence that the central nervous system is capable of a plastic response in Alzheimer's disease. Adaptive growth responses occur along with the degenerative events.

Extracorporeal Membrane Oxygenation (ECMO) has been used clinically as a life-saving treatment modality in infants and children who are dying of respiratory insufficiency. From 1973 to 1980 47 children less than 10 years of age were treated in a study to determine the feasibility and effectiveness of ECMO in the pediatric population. Despite a predicted mortality of 90% or greater, 24 patients survived. Eighteen of those patients have been seen in long-term follow-up. Thirteen patients (72%) demonstrate basically normal growth and development. Five patients (28%) have definite handicaps which are severe in two. Despite ligation of one common carotid artery and systemic heparinization, the risk of intracranial hemorrhage and/or neurodevelopmental problems appears to be no higher in this ECMO group and may even be lower than in the high-risk population treated with conventional therapy. The incidence of chronic respiratory problems, especially bronchopulmonary dysplasia, is zero in this group of patients. Only one patient (4%) has a defect that lateralizes to the right hemisphere which may have been affected by ligation of the carotid artery. Further study is required; however, it appears that ECMO offers life-saving intervention without increasing morbidity in select children with severe respiratory insufficiency.