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Biomedical subjects

G Constantopoulos

Publications and source records attributed to G Constantopoulos.

At least 19 recordsLinked to original sources
PubMed1992

Attempted enzyme replacement using human amnion membrane implantations in mucopolysaccharidoses.

Amnion membrane implantation has been proposed as an approach to enzyme replacement in mucopolysaccharidoses. Human amnion membranes have been subcutaneously implanted in the abdominal wall in 19 patients with mucopolysaccharidoses (MPS I, II and III). A protocol was developed for the objective evaluation of experimental treatments of these patients. Systematic evaluation of the clinical status before and 6 months after amnion membrane implantation reveals no change in function except improvement in joint mobility. The sum of all joint movements showed improvement from baseline values to 6 months after implantation by ANOVA followed by post-hoc analysis (p less than 0.056). The only specific joint movements to significantly improve after 6 months were shoulder extension (p less than 0.01) and hip internal rotation (p less than 0.05). Serial measurements of the deficient lysosomal enzyme activity in serum and white blood cells did not increase in any patient after amnion membrane implantation. Urinary glycosaminoglycan excretion decreased transiently in 2 of 10 patients after implantation, but a second amnion membrane implantation did not result in any change. Biopsy of the implantation site in 10 patients 6 months after amnion membrane implantation revealed a foreign-body reaction with giant cell formation and fibrosis and no recognizable amnion membrane tissue. We conclude that human amnion membrane implantation is not an effective therapy in mucopolysaccharidoses.

Abdominal Muscles↗
PubMed1991

Effect of dimethylsulfoxide on the proliferation and glycosaminoglycan synthesis of rat prostate adenocarcinoma cells (PAIII) in vitro: isolation and characterization of DMSO-resistant cells.

Dimethylsulfoxide (DMSO) modulates the tumorigenicity and other characteristics of some malignant cell lines in vitro. We have investigated DMSO effects on cell proliferation and glycosaminoglycan (GAG) synthesis in rat prostate adenocarcinoma (PAIII) cells in culture. DMSO inhibited cell proliferation and GAG synthesis and shedding. Cells that survived the initial exposure to 2.5% DMSO could be propagated in this concentration of the agent and were designated PAIII-DMSO resistant (PAIII-DMSOr). PAIII-DMSOr cells showed reversible indications of increased differentiation such as decreased growth rate and saturation density. Although the PAIII-DMSOr cells were grown in 2.5% DMSO, they had normal or elevated GAG content. The major GAG of both PAIII and PAIII-DMSOr cells was undersulfated heparan sulfate. Verapamil, a calcium channel blocker that reverses drug resistance in tumor cells, stimulated the growth of PAIII-DMSOr cells in the presence of 2.5% DMSO, but was inhibitory in the absence of DMSO. Growth of PAIII cells was inhibited by the differentiating agents sodium butyrate and retinoic acid and by the ionophore monensin. Interestingly, growth of PAIII-DMSOr cells in the presence of 2.5% DMSO was largely unaffected by sodium butyrate or retinoic acid. The results suggest that (1) PAIII-DMSOr cells arise from the induction of a compensation mechanism to DMSO effects in a preexisting population of cells: (2) there is a correlation between GAG synthesis and cell proliferation; and (3) further study of the verapamil effect may help elucidate the mechanism of the DMSO-induced differentiation of cancer cells.

Adenocarcinoma↗
PubMed1989

Long-term effects of bone marrow transplantation in dogs with mucopolysaccharidosis I.

The therapeutic effects of allogeneic bone marrow transplantation (BMT) in a canine model of mucopolysaccharidosis I (MPS I) were investigated. Long-term post-BMT pathologic and biochemical studies were performed on three groups of dogs: 1) MPS I-affected dogs that did not receive BMT, 2) MPS I-affected dogs that received total body irradiation followed by an allogeneic BMT, and 3) normal, unaffected dogs that served as BMT donors. All dogs were necropsied at approximately 20 months after BMT. The severity of MPS I-related lesions in the dogs receiving BMT was greatly diminished. These dogs had only slight cardiac valvular thickening, no meningeal thickening, no renal tubular epithelial vacuolation, decreased neuronal vacuolation, decreased corneal stromal vacuolation, and greatly diminished arterial medial thickening. The severity and incidence of degenerative arthropathy also were decreased in BMT dogs, however, vertebral lesions were similar to nontransplanted, affected dogs. Chondrocytes of both MPS I-BMT and MPS I-no BMT groups had similar marked cytoplasmic vacuolation, except for MPS I-BMT chondrocytes near the articular surface, which had more normal morphology. Ultrastructurally, the liver and kidney tissue in BMT recipients had no appreciable lysosomal accumulation of GAGs. These morphologic findings were supported by near normal levels and electrophoretic patterns of glycosaminoglycans (GAG) in most tissues of BMT recipient dogs. This study demonstrates that BMT is capable of substantially diminishing the severity of MPS I-related lesions in this canine model.

Animals↗
PubMed1989

Corneal opacity in canine MPS I. Changes after bone marrow transplantation.

Corneal opacification associated with glycosaminoglycan (GAG) deposition occurs in canine mucopolysaccharidosis I (MPS I), a deficiency of the lysosomal enzyme alpha-L-iduronidase. In affected dogs corneal lesions appear similar to those in children with the same disease. Transplantation of bone marrow from unaffected littermates was performed in 5 MPS I affected dogs at 5 months of age. In three recipients that became long-term survivors corneal clouding was largely alleviated compared to affected control dogs. In no case, however, did the corneas remain totally clear throughout the course of the study (594, 628 and 1425 days). Light and electron microscopic findings correlated with the clinical impression of partial improvement. Glycosaminoglycan analysis of corneal tissue from two transplant recipients, one normal littermate, and one MPS I-affected, untransplanted dog showed quantitative and qualitative changes in stored GAG following bone marrow transplantation.

Animals↗
PubMed1988

Multiple sulfatase deficiency with a novel biochemical presentation.

Deficient activities of cerebroside-sulfatase, N-Acetylgalactosamine-4-sulfatase and iduronide 2-sulfatase in the lymphocytes of a patient suspected of metachromatic leukodystrophy, established the diagnosis of multiple sulfatase deficiency (MSD). Cultured skin fibroblasts (of early passage) from the patient had normal levels of activity for the three sulfatases. One week after the first examination, the activities of the three sulfatases in the fibroblasts of the patient declined and within a month were 4%-29% of normal. Total urinary glycosaminoglycans were within normal range. However, further examination showed an increase in the concentration of heparan sulfate, which comprised more than 50% of the total, compared with less than 20% in normal controls. Urinary sulfatides, cholesterol esters, cholesterol, and triglycerides were increased. The results from the study of this unique case of MSD suggest that time-dependent changes affect the activities of sulfatases in MSD. These results also demonstrate the necessity of assaying the sulfatases in both lymphocytes and fibroblasts from suspected cases of MSD.

Acetylgalactosamine↗
PubMed1988

Biochemical and ultrastructural study of Blastocystis hominis.

This study was prompted by the paradox of strong presence of mitochondria in an anaerobic protozoan, recently reclassified from the yeasts. Stemming from publication in 1911 to 1912, Blastocystis hominis has been generally accepted as a harmless intestinal yeast of humans, with short standardized textbook (parasitology) descriptions, even to the present day. Reports since 1967 have changed the classification of B. hominis from yeast to protozoan (Sarcodina), and this has been followed by interest in B. hominis-caused disease, resulting in documentation of disease in humans and other primates. In this study of B. hominis, the basic ultrastructure of the mitochondria was shown by thin-section electron microscopy to be identical to that of an archetypical mitochondrion. There were hundreds of them in large B. hominis cells (100 to 200 microns in diameter). Mitochondria were confined to a peripheral ring of cytoplasm bounded by the outer cell membrane (there is no cell wall) and the membrane of the large, spherical, organelle-free central body that constitutes 75% of the cell's volume. Mitochondria tended to surround the cell's usual two to four nuclei. Rhodamine 123 stained the mitochondria selectively, visualized by fluorescence microscopy. The cell was devoid of cytochromes. Addition of 0.1% cytochrome c to the growth medium increased utilization of glucose by 34% and that of lactate by 17%. Furthermore, it markedly increased the number of mitochondrion-filled cells. At higher concentrations, cytochrome c inhibited the growth of the cells. Despite the presence of large numbers of mitochondria, activities of the mitochondrial enzymes pyruvate dehydrogenase complex, alpha-ketoglutarate dehydrogenase complex, isocitrate dehydrogenase, glutamate dehydrogenase, and cytochrome c oxidase were absent. Thus, the function of the mitochondria in B. hominis remains unknown. Considerable activities of aspartate aminotransferase and alanine aminotransferase were found. Aldolase activity was prominent. Pyruvate decarboxylase was present. Diaphorase and lactate dehydrogenase were detectable but in suspect quantities. Other missing enzymes were gamma glutamyl transpeptidase, alkaline phosphatase (a lysosomal marker), and creatine kinase isoenzymes.

Animals↗
PubMed1988

Multiple sulfatase deficiency.

Multiple sulfatase deficiency is an inherited disorder characterized by a deficiency of several sulfatases and the accumulation of sulfatides, glycosaminoglycans, sphingolipids, and steroid sulfates in tissues and body fluids. The clinical manifestations represent the summation of two diseases: late infantile metachromatic leukodystrophy and mucopolysaccharidosis. We present a 9-year-old girl with a phenotype similar to a mucopolysaccharidosis: short stature, microcephaly, and mild facial dysmorphism, along with dysphagia, retinal degeneration, developmental arrest, and ataxia. We discuss the importance of measuring the sulfatase activities in the leukocytes, and the instability of sulfatases in the cultured skin fibroblasts.

Cerebroside-Sulfatase↗
PubMed1987

Activities of oxidative enzymes in mycoplasmas.

The activities of several oxidoreductases were measured in three fermentative and two nonfermentative Mycoplasma species that were grown under aerobic or anaerobic conditions. Acholeplasma laidlawii MG, Mycoplasma hyorhinis GDL, and Mycoplasma pneumoniae FH had very high apparent activities of pyruvate dehydrogenase and pyruvate dehydrogenase complex compared with the activities of mammalian fibroblasts or human platelet-enriched preparations, while Mycoplasma salivarium VV and Mycoplasma arthritidis 07 had very low apparent activities of these two enzymes. Strictly anaerobic growth diminished both enzymatic activities. The activity of alpha-ketoglutarate dehydrogenase complex was minimal in all five mycoplasmas that were grown under aerobic conditions, anaerobic conditions, or both. All the mycoplasmas that were examined exhibited lactate dehydrogenase and NADH-dichlorophenol indophenol oxidoreductase activities. The properties of mycoplasmal pyruvate dehydrogenase complex suggest that it differs from the mammalian enzyme.

Arsenic↗
PubMed1987

Bone marrow transplantation in canine mucopolysaccharidosis I. Effects within the central nervous system.

Five dogs with mucopolysaccharidosis I, a model of human Hurler/Scheie syndrome, were transplanted with marrow from phenotypically normal littermates at 5 mo of age. At 3 and 9 mo posttransplantation, biopsies of cerebral cortex, liver, and cerebrospinal fluid were obtained. The alpha-L-iduronidase levels in these tissues were 0.8-7.4, 26-45, and 6.3-14.9% of the paired donor tissues, respectively. Although iduronidase was present in relatively low levels in the recipients' brains and cerebrospinal fluid at both biopsy times, reduction in brain glycosaminoglycan (GAG) was comparable to that observed in liver. Ultrastructural studies of cells within the transplanted dogs' brains showed less lysosomal distension and storage product than in affected, nontransplanted, littermate controls. The most marked clearing of stored GAG was in cells surrounding blood vessels, but decreased lysosomal storage in neurons and glial cells was also observed. Urinary GAG excretion also decreased to near normal levels by 5 mo posttransplantation.

Animals↗
PubMed1986

The suramin-treated rat as a model of mucopolysaccharidosis. Variation in the reversibility of biochemical and morphological changes among different organs.

We have examined the reversibility of the biochemical and pathological changes induced in the spleen, kidney and lung of the suramin-treated rat which we have previously proposed as a useful model of the human condition, mucopolysaccharidosis (MPS). Rats were injected with a single intravenous dose of suramin (250 mg/kg) and allowed to survive for periods of up to 6 months. The organs were examined for suramin content, pathological changes, biochemical storage of glycosaminoglycans (GAGs) and for the blockage of the relevant hydrolytic enzymes. The extent and rate of suramin accumulation and the retention of the drug varied considerably between organs with the greatest concentration of suramin (4,000 micrograms/g) occurring in the kidney 2 weeks after injection. Suramin persisted at gradually decreasing levels in all organs for the duration of the experiment, remaining at the highest level (1,150 micrograms/g) in the kidney. The concentration of GAGs peaked 10-18 days after administration of the drug, in all organs. Within 6 months the level had returned to normal in the liver, spleen and lung, but remained elevated in the kidney. The activities of beta-glucuronidase and acid phosphatase were decreased in all organs at diminishing levels throughout the experiment. There was a significant increase in the activity of arylsulphatase B, except in the kidney, where the predominant effect was a reduction of activity. Recovery from the morphological changes was evident in all organs except the lung within 6 months of suramin administration. The reversibility of the biochemical and pathological changes in the various tissues is discussed and compared with the earlier results described for the liver (Rees et al. 1986) and the implications of using suramin for the treatment of human trypanosomiasis, onchocerciasis and AIDS are considered.

Animals↗
PubMed1986

The suramin-treated rat as a model of mucopolysaccharidosis: reversibility of biochemical and morphological changes in the liver.

Rats treated with the trypanocidal drug suramin, a potent inhibitor of several lysosomal enzymes, develop a storage disorder which mimics the features of mucopolysaccharidosis (Constantopoulos et al. 1983). In this paper we have examined the reversibility of the biochemical and pathological changes induced in the liver of the suramin-treated rat. Rats were injected with a single intravenous dose of suramin (250 mg/kg) and allowed to survive for periods of up to 6 months. The liver was examined for suramin content, pathological changes, biochemical storage of glycosaminoglycans (GAGs) and for the blockade of the relevant hydrolytic enzymes. GAG storage in the liver peaked at approximately 14 days after administration of suramin when there was a five-fold increase in the GAG content. Thereafter GAGs decreased in parallel with the fall of suramin concentrations so that within 6 months the content had returned to control levels. The activity of most of the enzymes tested had also returned to control levels within 6 months. The pathological changes which are evident in the liver 1-2 weeks after administration of the drug had diminished considerably within 6 months. These results indicate that significant reversibility of both the biochemical and pathological changes induced by suramin occurs and they support the suitability of the suramin treated rat as a model to assess the value of therapeutic treatments of mucopolysaccharidosis.

Animals↗
PubMed1985

Neurochemical characterization of canine alpha-L-iduronidase deficiency disease (model of human mucopolysaccharidosis I).

This report presents the neurochemical findings on the first dog to die with deficiency of alpha-L-iduronidase (mucopolysaccharide alpha-L-iduronohydrolase; EC 3.2.1.76). The principal findings were (a) markedly increased glycosaminoglycan content in all neural tissues examined (from threefold in sciatic nerve to 15-fold in brainstem), (b) a modest increase in levels of gangliosides GM2, GM3, and GD3, particularly in gray matter, (c) excessive accumulation of glycosaminoglycans in the CSF, (d) the increased glycosaminoglycans were dermatan sulfate and heparan sulfate, and (e) the molecular weights of the liver glycosaminoglycans were shifted toward smaller sizes, indicating partial degradation. The canine disorder thus resembles mucopolysaccharidosis I in all aspects.

Animals↗
PubMed1977

Mucopolysaccharidosis type I, II, IIIA and V. Pathological and biochemical abnormalities in the neural and mesenchymal elements of the brain.

Histochemical and electron microscopic studies of the brains inclusive of the leptomeninges containing large blood vessels from 7 patients with mucopolysaccharidosis (MPS) I, II, IIIA and V showed marked increase in mesenchymal elements and the generalized presence of characteristic lesions around cerebral veins and arteries. The periadventitial space was greatly distended and filled with viscous fluid and numerous mononuclear cells containing large cytoplasmic vacuoles; these cells stained positively for glycosaminoglycans (GAG). In contrast, the neurons showed only a slight increase of GAG over the normal controls but contained an excessive amount of glycolipid-like material. The amount of GAG in the leptomeninges, inclusive of the large blood vessels, was 10.8, 6.5, 4.5 and 2.2 times greater in patients with MPS I, II, V and IIIA respectively, than the mean of unaffected controls. Dermatan sulfate (DS) accounted for most of the GAG increase in MPS I, II and V [mixed excretors of DS and heparan sulfate (HS)], and HS for the GAG increase in MPS IIIA (HS excretor). With the exception of the patient with MPS IIIA, whose GAG content and composition were the same in both the neural and mesenchymal elements, in all the other MPS types the mesenchymal elements contained more GAG, with a preponderance of DS. We conclude that the mesenchymal elements contribute substantially to the increased content of GAG in the brain and its coverings, mostly in the form of dermatan sulfate.

Adult↗
PubMed1977

Content and composition of urinary glycosaminoglycans in the patients with myoclonus epilepsy with and without Lafora bodies.

Content, composition and molecular weight distribution of the urinary glycosaminoglycans (GAG) were determined in five patients with progressive myoclonus epilepsy (PME). In one patient (Family B) this syndrome was associated with cerebral Lafora bodies and in four siblings of Family A, no Lafora bodies were present in brain biopsy. Only one of the five patients had a moderate increase of urinary GAG excretion as expressed by 24-h output or creatinine. The heparan sulfate component of the GAG was moderately increased in two other patients. The molecular weight distribution of the urinary GAG was normal. The results do not support the contention that urinary GAG excretion is abnormal in PME. Among nine lysosomal enzymes in leucocytes, only the activity of alpha-mannosidase was increased 3-fold in the four siblings.

Adolescent↗