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Biomedical subjects

R D Jolly

Publications and source records attributed to R D Jolly.

At least 91 records · Page 5Linked to original sources

An inherited cataract in New Zealand Romney sheep.

A bilateral cataract was noted to occur in sheep on a New Zealand Romney stud. Extensive breeding trials showed that this defect was inherited as an autosomal dominant. As such this form of cataract is of minimal importance to the sheep industry as control is merely by culling affected individuals.

Journal Article↗

Dwarfism in Hereford cattle: a genetic morphological and biochemical study.

A study of 40 Hereford cattle dwarfs in New Zealand confirmed that dwarfism in this country was morphologically the same as that described in North American Herefords and that its mode of inheritance was as an autosomal recessive trait. The histological architecture of growth plates was essentially normal but palisading columns were shorter and more irregular than in controls. A small proportion of chondrocytes in dwarf cartilage showed increased areas of cytoplasmic metachromasia, which probably coincided with increased cystic dilations of endoplasmic reticulum containing granular material as noted by electronmicroscopy. The above growth-plate abnormalities were neither prominent nor consistent enough to be of diagnostic significance; nor do they currently help understanding of the underlying pathogenic mechanism of dwarfing. Histological and mucopolysaccharide excretion studies unequivocally demonstrated that this disease is not a mucopolysaccharidosis as had previously been reported.

Journal Article↗

Mannosidosis: patterns of storage and urinary excretion of oligosaccharides in the bovine model.

Mannose and glucosamine-containing oligosaccharides were extracted from tissues of variously aged calves with mannosidosis. Whereas storage in the brain, and to a lesser extent in the pancreas and lymph nodes, was cumulative, that in the liver was relatively stable over the time period followed. It is suggested that in this latter organ the 15--20% residual alpha-mannosidase activity attributable to the mutant enzyme might be sufficient to normalise function. In the kidney, levels actually fell over the first 15--20 weeks of life and thereafter remained constant. It is postulated that, in foetal life, storage is cumulative but, after birth, storage material is lost from the kidney into the urine by degeneration and/or desquamation of renal tubular cells. From 20 weeks the amount lost is in equilibrium with that formed or absorbed by the tubular cells.

Animals↗

Mannosidosis of Angus calves.

Mannosidosis, an inherited lysosomal storage disease, was diagnosed in two purebred Angus calves in the United States. Calf 1 was 5 months old and calf 2 was 7 months old when they were necropsied. Both calves had a history of progressive incoordination and ataxia. Gross postmortem findings included moderate hydrocephalus. Histologic examination revealed intracytoplasmic vacuolation of neurons throughout spinal cord and brain as well as in exocrine pancreatic cells, reticuloendothelial cells of the liver, and medullary sinusoids of lymph nodes. Biochemical study of 61 blood samples from the first calf's herd revealed bimodal distribution of enzyme activity for mannosidase. Two populations could be distinguished in that herd, those with normal mannosidase activity and those heterozygous for the disease.

Animals↗

Inborn errors of lysosomal catabolism--principles of heterozygote detection.

Carriers of an inborn error of lysosomal catabolism can be recognized, as they have enzyme levels approximately half those of normal individuals. Of the various tissues readily available for assay, plasma and leukocytes and, in some situations, tears are preferred. Although mixed leukocytes have proved satisfactory in Tay-Sachs screening programs, purified preparations of granulocytes or lymphocytes will allow better discrimination in most situations. Enzymes are assayed relative to some other reference parameter which must be a constant or highly correlated with test enzyme activity. In the two mass screening programs in operation, beta-hexosaminidase A and alpha-mannosidase have both been assayed relative to total beta-hexosaminidase activity. Carrier detection is particularly important in X-linked diseases. The techniques used mostly involve hair roots or fibroblasts and depend on random inactivation of the X chromosome. In the mucolipidoses II and III, in which there are a number of deficient enzymes in cells, carriers may be identified on the basis of the ratio of beta-hexosaminidase I1 and I2 to total hexosaminidase.

Animals↗

Persistent lymphocytosis and virus-like particles in lymphocytes of sheep inoculated with cell-free extracts derived from ovine malignant lymphomas.

White cell counts of sheep inoculated in utero or at birth with cell-free extracts of ovine malignant lymphomas have been monitored for 5 yr. Of 28 inoculated sheep which have survived, 19 have shown persistent lymphocytosis. After 5 yr, no lymphomas had developed in the inoculated sheep. Electron-microscopic examination of short-term cultures of phytohaemaglutinin-stimulated lymphocytes from the sheep with persistent lymphocytosis has revealed virus-like particles in five of nine animals examined but none in similar cultures from 11 uninoculated sheep. The density of particles recovered from these cultures has been determined by centrifugation on caesium chloride isopycnic density as being 1.14--1.145 gm/microliter. These particles are not typical of oncornavirus as reported from sheep and cattle elsewhere and may represent a different type of virus or indeed be non-viral.

Animals↗

Canine Gaucher disease--the enzymic defect.

beta-Glucosidase activity was investigated in tissues from a case of canine Gaucher disease and from a normal dog. In the latter, enzyme activity showed two pH optima at pH 4-0-4-25 and pH 5-0-5-5. In Gaucher disease tissues, negligible activity could be measured at the mouse acidic pH.

Animals↗

Characterization of the mutant alpha-mannosidase in bovine mannosidosis.

Residual acidic alpha-mannosidase, varying in amount up to approx. 15% of normal values, can be measured in various organs of a calf with mannosidosis. The highest specific activity and relative proportion of residual activity were found in the liver. Chromatography on DEAE-cellulose showed that the residual activity was associated with two components, which were eluted at comparable positions with those found in normal tissues. The residual activity had a lower thermal stability and a higher K(m) value for a synthetic substrate than did the normal enzyme. No differences in molecular weight or electrophoretic mobility between normal acidic alpha-mannosidase and the residual activity were observed by gel filtration and electrophoresis on cellulose acetate respectively. The isoelectric focusing profiles for the alpha-mannosidase in the normal and pathological livers were very similar. It is suggested that a mutant enzyme, resulting from a mutation in a structural gene, accounts for the residual acidic alpha-mannosidase in mannosidosis. The mutant enzyme, which cross-reacts with antiserum raised against normal bovine acidic alpha-mannosidase, is present at a decreased concentration compared with the normal enzyme. There is a correlation between the concentrations of residual activity and cross-reacting material in mannosidosis. alpha-Mannosidase with a pH optimum of 5.75 and which is activated by Zn(2+) was also detected in the liver of the calf with mannosidosis. However, it is probably not a product of the defective gene because addition of Zn(2+) indicated that it was also present in normal tissues.

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The pathology of bovine mannosidosis.

Mannosidosis of Angus calves is an inherited lethal disease associated with a deficiency of the lysosomal enzyme alpha=mannosidase. It is characterised by vacuolation of neurons, macrophages, fixed reticuloendothelial cells, exocrine epithelial cells and to a lesser extent a wide variety of other cells. Vacuoles are shown to be membrane-bound vesicles and are considered to be secondary lysosomes in which are stored mannose-containing oligosaccharides that result from incomplete degradation of glycoproteins. Such glycoproteins may enter the lysomal system by heterophagy, autophagy or crinophagy. The presence in the pancreas of zymogen granules in storage vesicles indicates that incomplete degradation of secretory granules might help explain the widespread vacuolation of other exocrine cells. It is suggested that such granules may enter the lysosomal system by crinophagy.

Animals↗

Mannosidosis--pathogenesis of lesions in exocrine cells.

The finding of zymogen granules within lysosomal storage vesicles in pancreatic exocrine tissue in bovine mannosidosis may explain the widespread vacuolation of exocrine cells in this disease. It is uncertain if they enter the lysosomal system by the process of crinophagy but if so it would indicate that this regulatory mechanism could operate in normal exocrine tissue as well.

Animals↗