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Biomedical subjects

M Z Jones

Publications and source records attributed to M Z Jones.

At least 73 records · Page 4Linked to original sources
PubMed1983

Measurement of caprine plasma beta-mannosidase with a p-nitrophenyl substrate.

Experimental conditions for measuring caprine plasma beta-D-mannosidase activity are described with p-nitrophenyl-beta-D-mannopyranoside as a substrate. The plasma enzyme was stable for 3 months at -20 C or 1 week at 4 C. The optimal pH for activity was 5.0 in citrate-phosphate or acetate buffer. Enzyme activity was linear with time up to 24 hours at 37 C, but incubation of plasma at 56 C for 5 minutes resulted in loss of all activity. The apparent Michaelis-Menten constant (Km) for the plasma enzyme was 10.0 mM. Plasma beta-mannosidase from clinically normal and beta-mannosidosis carrier goats did not differ with respect to pH optimum, heat stability, or Km. The coefficient of variation for the assay, determined by assaying a plasma pool over a 3-month period, was 10.7% (mean: 115 nmole of p-nitrophenol formed/hour/ml of plasma). The assay described can be used to evaluate plasma beta-mannosidase measurements as a test for detecting carriers of caprine beta-mannosidosis, a newly described lysosomal storage disease.

Animals↗
PubMed1983

Caprine alpha- and beta-mannosidase activities: effects of age, sex, and reproductive status and potential use in heterozygote detection of beta-mannosidosis.

Effects of age, sex, and reproductive status on caprine plasma alpha- and beta-mannosidase activities were studied. The potential use of these plasma assays was evaluated for heterozygote detection of caprine beta-mannosidosis in populations of control goats and a breeding herd composed of known and putative heterozygotes for beta-mannosidosis. In the control population, the mean plasma alpha- and beta-mannosidase activities decreased in both sexes with maturity. Male goats generally had higher plasma mannosidase activity than did females, and plasma beta-mannosidase activity was affected by the reproductive status of the goats examined. Although putative carriers in the beta-mannosidosis breeding herd could not be differentiated from age- and sex-matched controls, known carriers had plasma beta-mannosidase values intermediate between those of control and affected goats. The lack of any correlation between alpha- and beta-mannosidase activities excluded alpha-mannosidase as a reference enzyme for carrier detection, but there are still differences between known carriers and the control population with respect to the alpha- and beta-mannosidase ratio.

Age Factors↗
PubMed1982

Plasma alpha- and beta-mannosidase activities in caprine beta-mannosidosis.

Plasma alpha- and beta-mannosidase activities were measured in goats with beta-mannosidosis, a recently discovered, inherited deficiency of the glycohydrolase beta-D-mannosidase. Plasma beta-mannosidase activity in the affected animals was zero at 1 and 4 weeks after they were born. Enzyme values of age-matched, unaffected goats were between 66 and 222 nmol/hr/ml of plasma, alpha-Mannosidase activities were similar in both affected and unaffected animals. This investigation indicates that deficiency of plasma beta-mannosidases activity may be diagnostic of beta-mannosidosis.

Animals↗
PubMed1981

Caprine oligosaccharide storage disease. Accumulation of beta-mannosyl (1 goes to 4) beta-N-acetylglucosaminyl (1 goes to 4) beta-N-acetylglucosamine in brain.

In 1975 a new caprine neurovisceral storage disease was identified in related Nubian goats in Michigan (Jones, M. Z., Cunningham, J. G., Dade, A. W., and Alessi, D. M. (1979) Soc. Neurosci. Abstr. 5, 513). The affected kids of both sexes showed profound neurological deficits at birth, lack of myelination in cerebral hemispheres and cerebellum, axonal lesions, and cytoplasmic vacuolation. A similar genetic syndrome arose independently in a population of Anglo-Nubian goats in New South Wales (Hartley, W. J., and Blakemore, W. F. (1973) Acta Neuropathol. 25, 325-333). Preliminary chemical characterization of an accumulated metabolite was performed. An extract of 1 g of brain from an affected goat was found to contain 2.2 mumol of the trisaccharide Man (beta 1 goes to 4)GlcNAc(beta 1 goes to 4)GlcNAc (beta-mannosylchitobiose). The accumulation of this substance suggests the possibility of a genetic defect in beta-mannosidase in the catabolic pathway for N-linked complex glycopeptides and would be the first indication of a beta-mannosidosis.

Animals↗
PubMed1981

Caprine beta-mannosidosis. Inherited deficiency of beta-D-mannosidase.

A rapidly fatal neurovisceral storage disease was discovered in both male and female offspring of clinically normal Nubian goats. Microscopic examination of fixed tissues revealed extensive demyelination and ubiquitous distribution of lysosomal storage vacuoles containing dispersed floccular material and membranous fragments. Urine was found to contain elevated levels of both mannose and N-acetylglucosamine, suggestive of an oligosaccharide storage disease. Brain was found to contain 2.2 mumol/g of a trisaccharide Man(beta 1-4)GlcNAc(beta 1-4)GlcNAc; (Jones, M. Z., and Laine, R. A. (1980) Fed. Proc. 39, 2521 and Jones, M. Z., and Laine, R. A. (1981) J. Biol. Chem. 256, 5181-5184). A profound deficiency of beta-D-mannosidase activity was found in a number of tissues from affected goats; obligate heterozygotes showed a partial enzyme deficiency. Other lysosomal hydrolase activities were normal or elevated over normal, including alpha-D-mannosidase, confirming that this was a hitherto undescribed inborn error of glycoprotein catabolism.

Animals↗
PubMed1980

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.

Animals↗
PubMed1980

Regeneration in the cerebellum following methylazoxymethanol-induced destruction of the external germinal layer. Morphological and biochemical studies.

In the cerebellum external germinal layer (EGL) regeneration was maximal 10 days following methylazoxymethanol-induced destruction of the postnatal mouse EGL. Similar patterns of EGL repair and delayed disappearance were observed in both anterior and posterior cerebellar lobes. Final reduction in granule cell number to 30-50% of control exceeded the reduction in basket and stellate cells. Morphological changes in GABAergic cell populations were paralleled by alterations in glutamic acid decarboxylase activity. These studies suggest that the regenerating EGL may be similar to the normal EGL with respect to the emerging cell types, but that granule cells which develop later are less completely represented.

Animals↗
PubMed1980

Cerebellar astrocytoma presenting as a cerebellar hemorrhage in a child.

An acute cerebellar hemorrhage in a 14-year-old girl was found to be caused by bleeding that had occured in an occult cerebellar astrocytoma. Such symptomatic hemorrhage into tumors, whether of metastatic or primary brain origin, occurs rarely but must be considered in patients of all ages who present with atypical strokes of presumed hemorrhagic etiology.

Adolescent↗
PubMed1977

Methylazoxymethanol-induced aberrant Purkinje cell dendritic development.

Purkinje cell dendrites develop with a specific orientation and relationship to related neurons and glia. Their dendritic spine postsynaptic membrane specialization may, in turn, require a permanent presynaptic contact by parallel fibers. To determine whether changes in the surrounding cells influence the normal development of the cerebellar Purkinje cell dendrites and spine specializations, destruction on the differentiating cell layer was induced in the postnatal mouse by administration of methylazoxymethanol acetate (MAM) (0.05 micronl/gm body weight) at day zero. The Purkinje cells were examined by light and electron microscopy on the tenth postnatal day. The midsagittal surface area of the cerebellar vermis in treated animals was reduced by an average of 60%. MAM-induced granule cell depletion and Purkinje cell dislocation were observed by light microscopy. When compared to controls, examination following Golgi impregnation revealed random orientation of Purkinje cell apical poles, and multiple primary dendrites of reduced length with few branches, branchlets and spines. Vertical processes of Golgi epithelial (Bergmann) cells were obliquely directed, reduced in length and complexity in MAM-treated mice. Ultrastructural examination revealed naked Purkinje cell dendritic spine specializations in both groups. Although necrotic debris persisted in astrocytes and macrophages, degenerating presynaptic terminals were not found. This study suggests that permanent presynaptic contact by parallel fibers is not essential for spine development. Astrocytic reactions to injury, in association with the reduced folial expansion, may have contributed to the observed abnormalities and disorientation of the Purkinje cells. The data suggests that Purkinje cell dendritic development may be strongly influenced by changes in surrounding cells.

Animals↗
PubMed1976

Pathogenesis of methylazoxymethanol-induced lesions in the postnatal mouse cerebellum.

Previous studies have shown that methylazoxymethanol acetate (MAM) and methylazoxymethanol glucoside (cycasin) cause destruction of differentiation cells in the postnatal mouse cerebellum. The major features of the resulting architectural disarray were Purkinje cell misalignment and granule cell deletion along with cerebellar dysfunction. Although it was clear from a number of studies that destruction of differentiation cells in the immediate postnatal period was the primary lesion, several important facets of the pathellular response to the injury was incompletely described. The relationship of the cellular response to the subsequent pathological alterations was not completely evaluated. Also, the presence of unattached Purkinje cell dendritic spine postsynpatic sites suggested that their development had occurred without presynaptic parallel fiber terminal differentiation. The possibility of early synaptogenesis and degeneration was not, however, completely ruled out.

Animals↗
PubMedDate not supplied

Becker-type muscular dystrophy.

This is a review of clinical, cardiologic, electrophysiologic, pathologic, and serum creatine kinase changes in eight families with slowly progressive X-linked Becker-type muscular dystrophy. All but one of the patients were able to walk until the age of 16 years, and most lived beyond 20. In every family, electromyography and muscle biopsy showed features which, on the basis of classical criteria, were interpreted as those of both myopathy and denervation, although among patients and among families, one or the other of these processes predominated. The most frequent biopsy picture was of fiber atrophy and hypertrophy, with many split and angulated fibers, and clumps of pyknotic nuclei. Necrosis, phagocytosis, regeneration, endomysial fibrosis, and some fatty infiltration were commonly seen. Review of a family originally described by Becker showed a similar biopsy picture; These pathologic changes are separable from those of Duchenne muscular dystrophy, but they often overlap with those seen in other chronic neuromuscular diseases.

Adolescent↗