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M S Sands

Publications and source records attributed to M S Sands.

At least 37 records · Page 2Linked to original sources
PubMed1998

Enzyme replacement therapy for murine mucopolysaccharidosis type VII leads to improvements in behavior and auditory function.

Mucopolysaccharidosis type VII (MPS VII; Sly syndrome) is one of a group of lysosomal storage diseases that share many clinical features, including mental retardation and hearing loss. Lysosomal storage in neurons of the brain and the associated behavioral abnormalities characteristic of a murine model of MPS VII have not been shown to be corrected by either bone marrow transplantation or gene therapy. However, intravenous injections of recombinant beta-glucuronidase initiated at birth reduce the pathological evidence of disease in MPS VII mice. In this study we present evidence that enzyme replacement initiated at birth improved the behavioral performance and reduced hearing loss in MPS VII mice. Enzyme-treated MPS VII mice performed similarly to normal mice and significantly better than mock- treated MPS VII mice in every phase of the Morris Water Maze test. In addition, the auditory function of treated MPS VII mice was dramatically improved, and was indistinguishable from normal mice. These data indicate that some of the learning, memory, and hearing deficits can be prevented in MPS VII mice if enzyme replacement therapy is initiated early in life. These data also provide functional correlates to the biochemical and histopathological improvements observed after enzyme replacement therapy.

Animals↗
PubMed1998

Murine mucopolysaccharidosis type VII: the impact of therapies on the clinical course and pathology in a murine model of lysosomal storage disease.

Murine mucopolysaccharidosis type VII (MPS VII) is a lysosomal storage disease caused by a recessively inherited deficiency of the lysosomal enzyme beta-glucuronidase. Affected mice have clinical, biochemical and pathological findings similar to those seen in humans with MPS VII (Sly syndrome), including growth retardation, facial dysmorphism, deafness, behavioural deficits and widespread glycosaminoglycan storage in lysosomes in the viscera, skeleton and brain. This mouse model is a useful tool for the evaluation of the effectiveness and experimental therapies for the MPS disorders. Syngeneic bone marrow transplantation performed in newborn MPS VII animals--before clinical evidence of disease is pronounced--prolongs life, improves hearing and bone growth, and prevents lysosomal storage in many sites, but does not correct the central nervous system disease. Enzyme therapy with beta-glucuronidase from the first days of life does reduce lysosomal storage in the brain in murine MPS VII. The enzyme-replaced mice also have reduced visceral lysosomal storage, impressive normalization of their phenotype and an improved life span. The effectiveness of gene therapy for the treatment of lysosomal storage disease has also been tested using the MPS VII model. When transplanted into MPS VII mice, syngeneic haematopoietic stem cells or mouse skin fibroblasts infected with retrovirus expressing beta-glucuronidase decreased storage, but only in the liver and spleen. Injection of an adenovirus vector expressing beta-glucuronidase into the vitreous of the MPS VII mice reduced storage in the retinal pigment epithelium and corneal endothelium. Intravenous administration of the adenovirus vector transduced with the beta-glucuronidase gene reduced liver and spleen storage and, when instilled into the cerebral ventricles, this viral vector caused beta-glucuronidase production in epithelial cells lining the ventricles. Recently, retroviral vector-corrected MPS VII fibroblasts secreting high levels of beta-glucuronidase were engrafted directly into the brains of adult MPS VII mice with resultant reduction in storage in neurons and glia adjacent to the grafts. Future efforts aimed at prolonging expression of the beta-glucuronidase gene by viral vectors and more precisely directing the therapeutic effect to the skeleton and brain will be important in optimizing treatments for murine MPS VII and extending the results of such therapies to humans with MPS.

Animals↗
PubMed1998

Intracisternal A-particle element transposition into the murine beta-glucuronidase gene correlates with loss of enzyme activity: a new model for beta-glucuronidase deficiency in the C3H mouse.

The severity of human mucopolysaccharidosis type VII (MPS VII), or Sly syndrome, depends on the relative activity of the enzyme beta-glucuronidase. Loss of beta-glucuronidase activity can cause hydrops fetalis, with in utero or postnatal death of the patient. In this report, we show that beta-glucuronidase activity is not detectable by a standard fluorometric assay in C3H/HeOuJ (C3H) mice homozygous for a new mutation, gusmps2J. These gusmps2J/gusmps2J mice are born and survive much longer than the previously characterized beta-glucuronidase-null B6.C-H-2(bm1)/ByBir-gusmps (gusmps/gusmps) mice. Northern blot analysis of liver from gusmps2J/gusmps2J mice demonstrates a 750-bp reduction in size of beta-glucuronidase mRNA. A 5.4-kb insertion in the Gus-sh nucleotide sequence from these mice was localized by Southern blot analysis to intron 8. The ends of the inserted sequences were cloned by inverse PCR and revealed an intracisternal A-particle (IAP) element inserted near the 3' end of the intron. The sequence of the long terminal repeat (LTR) regions of the IAP most closely matches that of a composite LTR found in transposed IAPs previously identified in the C3H strain. The inserted IAP may contribute to diminished beta-glucuronidase activity either by interfering with transcription or by destabilizing the message. The resulting phenotype is much less severe than that previously described in the gusmps/gusmps mouse and provides an opportunity to study MPS VII on a genetic background that clearly modulates disease severity.

Animals↗
PubMed1998

Gene therapy for lysosomal storage diseases.

The lysosomal storage diseases are a family of inherited disorders usually caused by a deficiency in a single lysosomal enzyme, and are characterised by progressive intralysosomal storage in multiple cell types. Although individual syndromes can be uncommon, as a whole this family of diseases affects approximately 1 in 3,000 live births. The severity of disease can be variable, ranging from minimal evidence of lysosomal storage to widespread multi-system involvement and early mortality. Although the enzymatic defects responsible for most of these diseases are known, treatment options for the majority of these disorders are limited to supportive care and genetic counselling. Knowledge of the genetic defects underlying these diseases, coupled with advances in the fields of gene transfer and expression, provide an opportunity to utilise gene therapy strategies in order to treat these disorders. Here we provide a description of the biochemical and molecular basis of gene therapy for lysosomal storage diseases, as well as an overview of some of the in vitro and in vivo studies that have been performed.

Journal Article↗
PubMed1997

Murine mucopolysaccharidosis type VII: long term therapeutic effects of enzyme replacement and enzyme replacement followed by bone marrow transplantation.

We demonstrated previously that short term administration of recombinant beta-glucuronidase to newborn mice with mucopolysaccharidosis type VII reduced lysosomal storage in many tissues. Lysosomal storage accumulated gradually after cessation of enzyme replacement therapy. Mice alive at 1 yr of age had decreased bone deformities and less lysosomal storage in cortical neurons. Here we compare the effects of long term enzyme replacement initiated either at birth or at 6 wk of age, and of enzyme administration initiated at birth followed by syngeneic bone marrow transplantation (BMT) at 5 wk of age. Several mice from each treatment group lived to at least 1 yr of age. Liver and spleen samples had beta-glucuronidase levels ranging from 2.4 to 19.8% of normal and showed a parallel decrease in lysosomal storage. The combination of enzyme replacement therapy followed by BMT reduced lysosomal distension in meninges, corneal fibroblasts, and bone when compared with treatment with enzyme alone. Mice treated at birth had less lysosomal storage in some neurons of the brain and the skeletal dysplasia was less severe when compared to mice whose treatment was delayed until 6 wk of age. We conclude that both enzyme replacement alone and early enzyme replacement followed by BMT have long term positive effects on murine mucopolysaccharidosis type VII. In addition, treatment started at birth is far more effective than treatment initiated in young adults.

Animals↗
PubMed1997

Gene therapy for murine mucopolysaccharidosis type VII.

Mucopolysaccharidosis type VII (MPS VII) is caused by a deficiency in the lysosomal enzyme beta-glucuronidase resulting in the accumulation of undegraded glycosaminoglycans in many tissues. A murine model of MPS VII shares many of the clinical, biochemical and histopathological features of human MPS VII and has provided an opportunity to study novel therapeutic approaches in a system with a uniform genetic background. Retroviral mediated gene therapy directed to the hematopoietic system or to artificial neo-organs resulted in low levels of enzyme in several tissues and reduced lysosomal storage in the liver and spleen. Partial correction of the disease in the eye was observed following an intravitreal injection of recombinant adenovirus. Neither retroviral nor adenoviral mediated gene transfer techniques resulted in a systemic reduction of lysosomal storage. Here we discuss several novel gene transfer approaches designed to increase the systemic levels of beta-glucuronidase in the MPS VII mouse.

Adenoviridae↗
PubMed1996

Enzyme replacement with recombinant beta-glucuronidase in murine mucopolysaccharidosis type VII: impact of therapy during the first six weeks of life on subsequent lysosomal storage, growth, and survival.

Treatment of mucopolysaccharidosis type VII (MPS VII) mice with recombinant mouse beta-glucuronidase injections has been shown to deliver enzyme to most tissues and to reduce lysosomal storage during the first 6 wk of life. Here we determine the effect of enzyme therapy limited to the first 6 wk of life on survival and growth and follow the subsequent accumulation of lysosomal storage after beta-glucuronidase treatment is discontinued. MPS VII mice received 28,000 U of beta-glucuronidase i.v. at weekly intervals from birth to 6 wk of life and were killed at intervals up to 1 y after the last injection. By 29 d after the last enzyme injection, lysosomal storage in bone was no different in amount than that seen in untreated MPS VII mice. By 85 d, the fixed tissue macrophage system, meninges, and brain glia had also accumulated storage comparable to that seen in untreated controls. One year after treatment, lysosomal storage was similar to that of untreated MPS VII mice in all sites except cortical neurons, where there was still a slight reduction. All treated mice that were not killed earlier, lived longer, were larger, and had milder facial and skeletal deformities than untreated MPS VII mice. These data show that enzyme replacement therapy in MPS VII mice during the first 6 wk of life improve survival and growth. After treatment is discontinued, storage accumulates slowly in the brain and more rapidly in the fixed tissue macrophage system. Whether therapy continued later in life can further improve survival and growth remains to be established.

Animals↗
PubMed1995

Syngeneic bone marrow transplantation reduces the hearing loss associated with murine mucopolysaccharidosis type VII.

MPS VII mice are deficient in beta-glucuronidase and share many clinical, biochemical, and pathologic characteristics with human mucopolysaccharidosis type VII (MPS VII). We have shown that syngeneic bone marrow transplantation (BMT) prolongs survival and reduces lysosomal storage in many organs of the MPS VII mouse. In this report, we quantify the hearing loss and determine the impact of syngeneic BMT on the development of deafness and the associated pathology in the MPS VII mouse. Eleven weeks after syngeneic BMT performed at birth, treated MPS VII mice had normal auditory-evoked brainstem responses (ABR), whereas untreated MPS VII mice had ABR thresholds 43 dB higher than normal. Treated MPS VII mice had beta-glucuronidase-positive cells in the temporal bone and in the subepithelial connective tissue of the external auditory canal. There was less thickening of the tympanic membrane and middle ear mucosa and decreased distortion of the ossicles and the cochlear bone. Although transplanted MPS VII mice had increased ABR thresholds by 33 weeks of age, four of the six had thresholds 12 to 32 dB lower than untreated mutants. These data indicate that syngeneic BMT in newborn MPS VII mice prevents early hearing loss and, in some animals, results in long-term improved auditory function.

Animals↗
PubMed1995

High level expression and export of beta-glucuronidase from murine mucopolysaccharidosis VII cells corrected by a double-copy retrovirus vector.

Retrovirus vectors were constructed to transfer and express the cDNA of the human lysosomal acid hydrolase beta-glucuronidase (GUSB) under control of the human GUSB promoter. Expression of the transcription unit (minigene) was evaluated in a GUSB-negative cell line established from a mouse with the lysosomal storage disease mucopolysaccharidosis (MPS) type VII. A vector designed to transfer single copies of the minigene (N2H beta H) expressed normal levels of GUSB activity in the deficient cells. GUSB expression was increased to several times greater than normal by inserting the minigene into a double-copy vector (DCH beta H), which places one copy of the transcription unit upstream of the retrovirus promoter in both the 3' and 5' long terminal repeats (LTRs) of the integrated provirus. The specific activity of GUSB and a control normal lysosomal enzyme, alpha-galactosidase (GLA), were higher in normal and in vector-corrected cells from confluent cultures than in subconfluent dividing cells. The ratios of GUSB to GLA were similar at all phases of cell growth, but the level of GUSB expression from the double copy vector was several-fold higher than from the single copy vector. To determine if this effect was controlled by the GUSB promoter, a vector was constructed using the thymidine kinase (TK) promoter to drive the human GUSB cDNA (NTK beta H). The levels of GUSB in cells corrected with this vector exhibited the same cell density dependent pattern as when the GUSB promoter was used, indicating that the variation in enzymatic activity was not a function of the GUSB promoter.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Enzyme replacement therapy for murine mucopolysaccharidosis type VII.

Recombinant mouse beta-glucuronidase administered intravenously to newborn mice with mucopolysaccharidosis type VII (MPS VII) is rapidly cleared from the circulation and localized in many tissues. Here we determine the tissue distribution of injected enzyme and describe its effects on the histopathology in 6-wk-old MPS VII mice that received either one injection of 28,000 U recombinant beta-glucuronidase at 5 wk of age or received six injections of 28,000 U given at weekly intervals beginning at birth. These mice were compared with untreated 6-wk-old MPS VII mice. The single injection decreased lysosomal distention in the fixed tissue macrophage system. MPS VII mice that received multiple injections had 27.8, 3.5, and 3.3% of normal levels of beta-glucuronidase in liver, spleen, and kidney, respectively. Brain had detectable beta-glucuronidase, ranging from 2.0-12.1% of normal. Secondary elevations of alpha-galactosidase and beta-hexosaminidase in brain, spleen, liver, and kidney were decreased compared with untreated MPS VII mice. Although no improvement was observed in chondrocytes, glia, and some neurons, the skeleton had less clinical and pathological evidence of disease and the brain had reduced lysosomal storage in meninges and selected neuronal groups. These data show that recombinant beta-glucuronidase treatment begun in newborn MPS VII mice provides enzyme to most tissues and significantly reduces or prevents the accumulation of lysosomal storage during the first 6 wk of life. Whether therapy begun later in life can achieve this level of correction remains to be established.

Animals↗
PubMed1994

Behavioral consequences of bone marrow transplantation in the treatment of murine mucopolysaccharidosis type VII.

The gusmps/gusmps mouse is a model of the human lysosomal storage disease mucopolysaccharidosis type VII caused by deficient beta-glucuronidase activity. Bone marrow transplantation has been shown to correct some of their biochemical and pathological abnormalities but its efficacy in correcting their neurological functional deficits is unknown. We transplanted the neonatal gusmps/gusmps mice and their normal controls and evaluated their central nervous system function with two behavioral tests: the grooming test, a developmentally regulated and genetically based activity, and a Morris water maze test which assessed spatial learning abilities. The two transplanted groups groomed less than the normals, were unable to remember the location of an invisible platform from day to day, and were severely impaired at developing strategies to locate the platform in unfamiliar locations. The performance of both normal and mutant transplanted groups was clearly inferior to the untreated normals and, in some instances, close to or worse than the untreated mutants, even though the enzyme abnormalities of the mutants have been partially corrected. Hence, the behavioral deficits in the mutant mice were not restored to normal while similarly treated normal mice showed significant functional deterioration, indicating the detrimental consequence of this therapy in the neonatal period.

Analysis of Variance↗
PubMed1993

A single-base-pair deletion in the beta-glucuronidase gene accounts for the phenotype of murine mucopolysaccharidosis type VII.

Murine mucopolysaccharidosis type VII is a heritable disease caused by a spontaneous mutation, gus(mps), closely linked to the beta-glucuronidase structural gene on chromosome 5. Mice homozygous for the mutation have a > 200-fold decrease in beta-glucuronidase mRNA levels and virtually no enzyme activity detectable by a sensitive fluorometric assay. Approximately 20 kb of genomic DNA containing the beta-glucuronidase gene Gus and > 2 kb of 5' and 3' flanking sequences were cloned from both a gus(mps)/gus(mps) mouse and a +/+ mouse of the progenitor strain. Restriction enzyme digests containing DNA fragments 20-400 bp in length were generated from each of the two Gus alleles and then compared by using nondenaturing polyacrylamide DNA-sequencing gels. This method rapidly identified a large number of restriction sites and was sensitive enough to detect a restriction fragment length variation resulting from a 1-bp deletion in the gus(mps) allele. DNA-sequence analysis of the mutant genomic fragment showed that the 1-bp deletion created a frameshift mutation within exon 10. Insertion of the deleted nucleotide by oligonucleotide site-directed mutagenesis restored function to the corrected mutant gene when transfected into gus(mps)/gus(mps) fibroblasts. We concluded that the frameshift mutation, which introduces a premature stop codon at codon 497 in exon 10, accounts for the molecular, biochemical, and pathological abnormalities associated with the gus(mps) phenotype.

Alleles↗
PubMed1993

Treatment of murine mucopolysaccharidosis type VII by syngeneic bone marrow transplantation in neonates.

BACKGROUND: Bone marrow transplantation (BMT) proved an effective therapy for murine mucopolysaccharidosis type VII (MPS VII) in adult gusmps/gusmps mice with well developed clinical and pathologic characteristics of the disease. MPS VII mice transplanted as adults had a marked decrease in lysosomal storage material in many organs, although not in the skeleton and brain (1). Since untreated newborn MPS VII mice appear normal and have minimal lysosomal storage material detectable microscopically, we postulated that BMT in newborn mice might prevent the subsequent accumulation of storage material. EXPERIMENTAL DESIGN: One-day-old mutant and phenotypically normal mice were exposed to 2, 4, 6 and 8 Gray and then injected intravenously with syngeneic bone marrow cells from homozygous normal females. Transplanted mice were examined biochemically and microscopically at 10 weeks and 10 months of age. RESULTS: Newborn mice receiving BMT lived longer than untreated mutants, had less severe facial dysmorphism, and better mobility. beta-Glucuronidase activity in liver, spleen, kidney and brain increased with increasing radiation dose. The secondary elevations of alpha-galactosidase and beta-hexosaminidase observed in MPS VII, were significantly reduced in liver and spleen in all radiation groups. Treated mutants had less histologic evidence of lysosomal storage disease in bones, joints and periarticular tissue as compared with untreated mutants. Neonatal BMT also reduced storage in the leptomeninges, ependyma and retinal pigment epithelium and caused a slight decrease in neuronal storage at high radiation dose. Radiation dose dependent cerebellar and retinal dysplasia and long bone growth retardation was observed when the therapy was initiated in newborn mice but not when the animals were transplanted as adults. CONCLUSIONS: BMT is a more effective therapy for MPS VII when it is performed at birth rather than in adults. Alternate means of ablating host hematopoietic stem cells should be employed as a pretreatment for BMT due to the severe side effects of radiation on newborns.

Animals↗
PubMed1992

Binding of TFIIIA to derivatives of 5S RNA containing sequence substitutions or deletions defines a minimal TFIIIA binding site.

The repetitive zinc finger domain of transcription factor IIIA binds 5S DNA and 5S RNA with similar affinity. Site directed mutagenesis of the Xenopus borealis somatic 5S RNA gene has been used to produce a series of derivatives of 5S RNA containing local sequence substitutions or sequence deletions. Gel mobility shift analyses of the binding of TFIIIA to these altered 5S RNAs revealed that all three of the helical stems of the 5S RNA secondary structure are required for binding. TFIIIA was observed to bind with normal affinity to RNAs lacking 12 nucleotides at either the loop c or loop e/helix V regions of 5S RNA, as well as to a double mutant containing both deletions. The secondary structure of the resulting 96-nucleotide RNA, studied using structure-specific ribonucleases, was found to resemble the central portion of 5S RNA.

Animals↗
PubMed1991

The carboxyterminal zinc fingers of TFIIIA interact with the tip of helix V of 5S RNA in the 7S ribonucleoprotein particle.

Immature Xenopus laevis oocytes contain large quantities of a 7S ribonucleoprotein particle containing transcription factor IIIA (TFIIIA) and 5S RNA in a 1:1 molar ratio. We have reconstituted RNPs containing 5S RNA and either intact TFIIIA or proteolytic fragments that represent progressive C-terminal deletions of the protein. A partial trypsin digestion fragment encompassing the amino terminal seven zinc fingers of TFIIIA rebinds 5S RNA with nearly the same affinity as intact TFIIIA. We have compared the RNase protection patterns resulting from binding of intact and deleted forms of TFIIIA. RNAse protection assays using cobra venom nuclease were performed on complexes reconstituted with 5' and 3' end-labeled 5S RNA. Similar experiments with 3' end-labeled 5S RNA were performed with nuclease alpha-sarcin. With both nucleases, nucleotides in helix V of 5S RNA show more complete protection from nuclease cleavage when the RNA is bound to intact TFIIIA than when it is bound to a 20 kDa tryptic fragment of TFIIIA lacking the C-terminal portion of the protein. These results suggest that fingers 8 and 9 of TFIIIA interact with the distal portion of helix V in the 5S RNA.

Animals↗
PubMed1991

Two zinc finger proteins from Xenopus laevis bind the same region of 5S RNA but with different nuclease protection patterns.

Immature oocytes from Xenopus laevis contain a 42S ribonucleoprotein particle (RNP) containing 5S RNA, tRNA, a 43 kDa protein, and a 48 kDa protein. A particle containing 5S RNA and the 43 kDa protein (p43-5S) liberated from the 42S particle upon brief treatment with urea can be purified by anion exchange chromatography. The purified p43-5S RNA migrates as a distinct species during electrophoresis on native polyacrylamide gels. Radiolabeled 5S RNA can be incorporated into the p43-5S complex by an RNA exchange reaction. The resulting complexes containing labeled 5S RNA have a mobility on polyacrylamide gels identical to that of purified p43-5S RNPs. RNP complexes containing 5S RNA labeled at either the 5' or 3' end were probed with a variety of nucleases in order to identify residues protected by p43. Nuclease protection assays performed with alpha-sarcin indicate that p43 binds primarily helices I, II, IV, and V of 5S RNA. This is the same general binding site observed for TFIIIA on 5S RNA. Direct comparison of the binding sites of p43 and TFIIIA with T1 and cobra venom nucleases reveals striking differences in the protection patterns of these two proteins.

Animals↗
PubMed1987

Computed tomographic enhancement of liver and spleen in the dog with iodipamide ethyl ester particulate suspensions.

Particulate suspensions have been developed for use as contrast agents to aid in the detection of hepatic lesions by CT. In several previous rodent studies, the toxicity and tissue concentrations of iodipamide ethyl ester (IDE) particles have been evaluated. The purpose of this study was to determine the pharmacokinetics of IDE in three dogs by evaluation of CT enhancement. Serum chemistry and hematologic parameters after intravenous administration were also followed. A dose of 75 mgI/kg IDE caused an increase of 40-60 Hounsfield units (HU) in liver attenuation, which persisted from 5 minutes to ten hours postinfusion. No enhancement of tissues other than liver and spleen was observed. IDE was completely eliminated from the liver within seven days. A mild transient elevation of liver enzymes may be attributable to the use of barbiturates rather than IDE. A transient depression of the white blood count was the only biochemical or hematologic change that was clearly in response to the infusion of IDE particulates.

Animals↗