Impact of polygenic schizophrenia-related risk and hippocampal volumes on the onset of psychosis

Alterations in hippocampal volume are a known marker for first-episode psychosis (FEP) as well as for the clinical high-risk state. The Polygenic Schizophrenia-related Risk Score (PSRS), derived from a large case-control study, indicates the polygenic predisposition for schizophrenia in our clinical sample. A total of 65 at-risk mental state (ARMS) and FEP patients underwent structural magnetic resonance imaging. We used automatic segmentation of hippocampal volumes using the FSL-FIRST software and an odds-ratio-weighted PSRS based on the publicly available top single-nucleotide polymorphisms from the Psychiatric Genomics Consortium genome-wide association study (GWAS). We observed a negative association between the PSRS and hippocampal volumes (β=-0.42, P=0.01, 95% confidence interval (CI)=(-0.72 to -0.12)) across FEP and ARMS patients. Moreover, a higher PSRS was significantly associated with a higher probability of an individual being assigned to the FEP group relative to the ARMS group (β=0.64, P=0.03, 95% CI=(0.08-1.29)). These findings provide evidence that a subset of schizophrenia risk variants is negatively associated with hippocampal volumes, and higher values of this PSRS are significantly associated with FEP compared with the ARMS. This implies that FEP patients have a higher genetic risk for schizophrenia than the total cohort of ARMS patients. The identification of associations between genetic risk variants and structural brain alterations will increase our understanding of the neurobiology underlying the transition to psychosis.

Superior bit error rate and jitter due to improved switching field distribution in exchange spring magnetic recording media

We report two effects that lead to a significant reduction of the switching field distribution in exchange spring media. The first effect relies on a subtle mechanism of the interplay between exchange coupling between soft and hard layers and anisotropy that allows significant reduction of the switching field distribution in exchange spring media. This effect reduces the switching field distribution by about 30% compared to single-phase media. A second effect is that due to the improved thermal stability of exchange spring media over single-phase media, the jitter due to thermal fluctuation is significantly smaller for exchange spring media than for single-phase media. The influence of this overall improved switching field distribution on the transition jitter in granular recording and the bit error rate in bit-patterned magnetic recording is discussed. The transition jitter in granular recording for a distribution of K_hard values of 3% in the hard layer, taking into account thermal fluctuations during recording, is estimated to be a = 0.78 nm, which is similar to the best reported calculated jitter in optimized heat-assisted recording media.

Health and social support services in older adults recently discharged from hospital: service utilisation and costs and exploration of the impact of a home-exercise intervention

BACKGROUND

Admission to hospital can lead to persistent deterioration in physical functioning, particularly for the more vulnerable older population. As a result of this physical deterioration, older people who have been recently discharged from hospital may be particularly high users of health and social support services. Quantify usage and costs of services in older adults after hospitalisation and explore the impact of a home-exercise intervention on service usage.

METHOD

The present study was a secondary analysis of data from a randomised controlled trial (ACTRN12607000563460). The trial involved 340 participants aged 60 years and over with recent hospitalisation. Service use and costs were compared between intervention (12 months of home-exercise prescribed in 10 visits from a physiotherapist) and control groups.

RESULTS

33 % of participants were re-admitted to hospital, 100 % consulted a General Medical Practitioner and 63 % used social services. 56 % of costs were associated with hospital admission and 22 % with social services. There was reduction in General Medical Practitioner services provided in the home in the intervention group (IRR 0.23, CI 0.1 to 0.545, p < 0.01) but no significant between-group difference in service use or in costs for other service categories.

CONCLUSION

There appears to be substantial hospital and social service use and costs in this population of older people. No significant impact of a home-based exercise program was evident on service use or costs.

TRIAL REGISTRATION

Australian and New Zealand Clinical Trial Registry ACTRN12607000563460 >TrialSearch.

Disease correction by combined neonatal intracranial AAV and systemic lentiviral gene therapy in Sanfilippo Syndrome type B mice

Mucopolysaccharidosis type IIIB (MPS IIIB) or Sanfilippo Syndrome type B is a lysosomal storage disease resulting from the deficiency of N-acetyl glucosaminidase (NAGLU) activity. We previously showed that intracranial adeno-associated virus (AAV) -based gene therapy results in partial improvements of several aspects of the disease. In an attempt to further correct the disease, MPS IIIB mice were treated at 2–4 days of age with intracranial AAV2/5-NAGLU (IC-AAV), intravenous lentiviral-NAGLU (IV-LENTI) or the combination of both (BOTH). The BOTH group had the most complete biochemical and histological improvements of any treatment group. Compared to untreated MPS IIIB animals, all treatments resulted in significant improvements in motor function (rotarod) and hearing (auditory-evoked brainstem response). In addition, each treatment group had a significantly increased median life span compared to the untreated group (322 days). The combination arm had the greatest increase (612 days), followed by IC-AAV (463 days) and IV-LENTI (358 days). Finally, the BOTH group had nearly normal circadian rhythm measures with improvement in time to activity onset. In summary, targeting both the systemic and central nervous system disease of MPS IIIB early in life appears to be the most efficacious approach for this inherited metabolic disorder.

A genome-wide survey and functional brain imaging study identify CTNNBL1 as a memory-related gene

Unbiased genome-wide screens combined with imaging data on brain function may identify novel molecular pathways related to human cognition. Here we performed a dense genome-wide screen to identify episodic memory-related gene variants. A genomic locus encoding the brain-expressed beta-catenin-like protein 1 (CTNNBL1) was significantly (P=7 × 10(-8)) associated with verbal memory performance in a cognitively healthy cohort from Switzerland (n=1073) and was replicated in a second cohort from Serbia (n=524; P=0.003). Gene expression studies showed CTNNBL1 genotype-dependent differences in beta-catenin-like protein 1 mRNA levels in the human cortex. Functional magnetic resonance imaging in 322 subjects detected CTNNBL1 genotype-dependent differences in memory-related brain activations. Converging evidence from independent experiments and different methodological approaches suggests a role for CTNNBL1 in human memory.

A genome-wide survey of human short-term memory

Recent advances in the development of high-throughput genotyping platforms allow for the unbiased identification of genes and genomic sequences related to heritable traits. In this study, we analyzed human short-term memory, which refers to the ability to remember information over a brief period of time and which has been found disturbed in many neuropsychiatric conditions, including schizophrenia and depression. We performed a genome-wide survey at 909 622 polymorphic loci and report six genetic variations significantly associated with human short-term memory performance after genome-wide correction for multiple comparisons. A polymorphism within SCN1A (encoding the α subunit of the type I voltage-gated sodium channel) was replicated in three independent populations of 1699 individuals. Functional magnetic resonance imaging during an n-back working memory task detected SCN1A allele-dependent activation differences in brain regions typically involved in working memory processes. These results suggest an important role for SCN1A in human short-term memory.

Genome-wide linkage analysis of ADHD using high-density SNP arrays: novel loci at 5q13.1 and 14q12

Previous genome-wide linkage studies applied the affected sib-pair design; one investigated extended pedigrees of a genetic isolate. Here, results of a genome-wide high-density linkage scan of attention-deficit/hyperactivity disorder (ADHD) using an array-based genotyping of approximately 50 K single nucleotide polymorphism (SNPs) markers are presented. We investigated eight extended pedigrees of German origin that were non-related, not part of a genetic isolate and ascertained on the basis of clinical referral. Two parametric analyses maximizing LOD scores (MOD) and a non-parametric analysis for both a broad and a narrow phenotype approach were conducted. Novel linkage loci across all families were detected at 2q35, 5q13.1, 6q22-23 and 14q12, within individual families at 18q11.2-12.3. Further linkage regions at 7q21.11, 9q22 and 16q24.1 in all families, and at 1q25.1, 1q25.3, 9q31.1-33.1, 9q33, 12p13.33, 15q11.2-13.3 and 16p12.3-12.2 in individual families replicate previous findings. High-resolution linkage mapping points to several novel candidate genes characterized by dense expression in the brain and potential impact on disorder-relevant synaptic transmission. Our study provides further evidence for common gene effects throughout different populations despite the complex multifactorial etiology of ADHD.

Clinical response to persistent, low-level beta-glucuronidase expression in the murine model of mucopolysaccharidosis type VII

Mucopolysaccharidosis type VII (MPS VII) is a lysosomal storage disease caused by beta-glucuronidase (GUSB) deficiency. This disease exhibits a broad spectrum of clinical signs including skeletal dysplasia, retinal degeneration, cognitive deficits and hearing impairment. Sustained, high-level expression of GUSB significantly improves the clinical course of the disease in the murine model of MPS VII. Low levels of enzyme expression (1-5% of normal) can significantly reduce the biochemical and histopathological manifestations of MPS VII. However, it has not been clear from previous studies whether persistent, low levels of circulating GUSB lead to significant improvements in the clinical presentation of this disease. We generated a rAAV2 vector that mediates persistent, low-level GUSB expression in the liver. Liver and serum levels of GUSB were maintained at approximately 5% and approximately 2.5% of normal, respectively, while other tissue ranged from background levels to 0.9%. This level of activity significantly reduced the secondary elevations of alpha-galactosidase and the levels of glycosaminoglycans in multiple tissues. Interestingly, this level of GUSB was also sufficient to reduce lysosomal storage in neurons in the brain. Although there were small but statistically significant improvements in retinal function, auditory function, skeletal dysplasia, and reproduction in rAAV-treated MPS VII mice, the clinical deficits were still profound and there was no improvement in lifespan. These data suggest that circulating levels of GUSB greater than 2.5% will be required to achieve substantial clinical improvements in MPS VII.

Intrathecal enzyme replacement therapy reduces lysosomal storage in the brain and meninges of the canine model of MPS I

Enzyme replacement therapy (ERT) has been developed for several lysosomal storage disorders, including mucopolysaccharidosis I (MPS I), and is effective at reducing lysosomal storage in many tissues and in ameliorating clinical disease. However, intravenous ERT does not adequately treat storage disease in the central nervous system (CNS), presumably due to effects of the blood-brain barrier on enzyme distribution. To circumvent this barrier, we studied whether intrathecal (IT) recombinant human alpha-L-iduronidase (rhIDU) could penetrate and treat the brain and meninges. An initial dose-response study showed that doses of 0.46-4.14 mg of IT rhIDU successfully penetrated the brain of normal dogs and reached tissue levels 5.6 to 18.9-fold normal overall and 2.7 to 5.9-fold normal in deep brain sections lacking CSF contact. To assess the efficacy and safety in treating lysosomal storage disease, four weekly doses of approximately 1 mg of IT rhIDU were administered to MPS I-affected dogs resulting in a mean 23- and 300-fold normal levels of iduronidase in total brain and meninges, respectively. Quantitative glycosaminoglycan (GAG) analysis showed that the IT treatment reduced mean total brain GAG to normal levels and achieved a 57% reduction in meningeal GAG levels accompanied by histologic improvement in lysosomal storage in all cell types. The dogs did develop a dose-dependent immune response against the recombinant human protein and a meningeal lymphocytic/plasmacytic infiltrate. The IT route of ERT administration may be an effective way to treat the CNS disease in MPS I and could be applicable to other lysosomal storage disorders.

In utero fetal liver cell transplantation without toxic irradiation alleviates lysosomal storage in mice with mucopolysaccharidosis type VII

Lysosomal storage diseases, such as Mucopolysaccharidosis type VII (MPS VII), cause progressive loss of mobility and intellect and result in early death. Treatment of progressive diseases must occur before the blood-brain barrier closes. In MPS VII mice, normal donor hematopoietic cells secrete the missing enzyme beta-glucuronidase (GUSB) that reverses disease manifestations. Correction of lysosomal storage is limited to the visceral organs unless transplantation is preceded by high-dose irradiation. We hypothesize that irradiation opens the blood-brain barrier allowing passage of corrective cells. Here we transplanted genetically myeloablated MPS VII fetuses to determine whether earlier treatment without toxic irradiation is systemically corrective. Cells with a selective advantage in utero were identified. Donor fetal liver cells (FLC), a substitute for difficult to obtain murine cord blood cells, were increased 10-fold in the host peripheral blood over equivalent numbers of adult marrow cells injected simultaneously and were stable long term in both primary and secondary hosts. GUSB- MPS VII fetuses injected with GUSB+ FLC were assessed longitudinally after birth. Donor FLC replaced host stem cell descendants, prolonged life dramatically, and reduced bone dysplasia and lysosomal storage in all tissues long term. GUSB, donor leptomeningeal cells, and microglia were present in the brain at 11 months postinjection. Lysosomal storage in cortical neurons and glia, although not completely corrected, was reduced. We conclude that in utero intervention without toxic pretreatment in this model reduces the storage disease long term and improves the length and quality of life despite exerting only minor effects on the brain.

Observed incidence of tumorigenesis in long-term rodent studies of rAAV vectors

Gene therapy using recombinant adeno-associated virus vectors (rAAV) is generally considered safe. During the course of a study designed to determine the long-term efficacy of rAAV-mediated gene therapy initiated in newborn mice with the lysosomal storage disease, mucopolysaccharidosis type VII (MPSVII), a significant incidence of hepatocellular carcinomas and angiosarcomas was discovered. A hepatocellular carcinoma was first detected in a 35-week-old mouse and by 72 weeks of age, three out of five rAAV-treated MPSVII mice had similar lesions. These types of tumors had not been seen previously in long-term studies of MPSVII mice using recombinant enzyme or bone marrow transplantation. In an attempt to ascertain whether mouse strain or GUSB expression confers susceptibility to tumor formation, we histopathologically examined untreated normal mice of the same strain, untreated MPSVII mice, and normal mice overexpressing human GUSB for the presence of tumors and increased hepatocyte replication. The results of these studies do not indicate that MPSVII mice or mice overexpressing human GUSB are susceptible to tumor formation; however, the number of animals examined is too small to draw definitive conclusions. Results from quantitative PCR performed on the tumor samples suggest that the tumors are probably not caused by an insertional mutagenesis event followed by the clonal expansion of a transformed cell. In a separate study, a relatively large group of mice injected with varying doses and types of rAAV vectors had no evidence of hepatic or vascular tumors. Although the mechanism of tumor formation is currently unknown, the tumorigenic potential of rAAV vectors must be rigorously determined in long-term in vivo studies.

Murine mucopolysaccharidosis VIL: impact of therapies on the phenotype, clinical course, and pathology in a model of a lysosomal storage disease

The mucopolysaccharidoses are a group of lysosomal storage diseases caused by deficiency of an enzyme required for the normal degradation of glycosaminoglycans. Patients with mucopolysaccharidosis typically have widespread lysosomal storage, skeletal and central nervous system disease, and hepatosplenomegaly. Some patients with mucopolysaccharidosis may benefit from enzyme replacement therapy or bone marrow transplantation. Animal models of mucopolysaccharidosis have proven valuable for the evaluation of the effectiveness of potential treatments for patients with lysosomal storage disease. A murine model of MPS VII (Sly syndrome) has proven particularly useful because of its well-defined genetics and its well-characterized clinical, pathologic, and biochemical alterations, which resemble those seen in patients with mucopolysaccharidosis. Correction of these alterations forms the basis for evaluation of the effectiveness of novel treatments. A wide range of therapies have been tested using this model, including enzyme replacement therapy, bone marrow, stem cell, and neural progenitor cell transplantation, and a variety of viral-mediated gene therapies. The inferences drawn from these therapeutic studies using the murine MPS VII model are likely generalizable to other lysosomal storage diseases.

A novel model of murine mucopolysaccharidosis type VII due to an intracisternal a particle element transposition into the beta-glucuronidase gene: clinical and pathologic findings

We describe the clinical and pathologic findings in a murine model of mucopolysaccharidosis VII (Sly disease) that arose spontaneously in the C3H/HeOuJ mouse strain. Affected gus(mps2J)/gus(mps2J) mice are deficient in beta-glucuronidase because of insertion of an intracisternal A particle element into intron 8 of the gus structural gene. This is the first model of a human lysosomal storage disease caused by an intracisternal A particle element insertion. Mice with the gus(mps2J)/gus(mps2J) genotype have < 1% of normal beta-glucuronidase activity and secondary elevations of other lysosomal enzymes. The phenotype includes shortened life-span, dysmorphic features, and skeletal dysplasia. Lysosomal storage of glycosaminoglycans is widespread and affects the brain, skeleton, eye, ear, heart valves, aorta, and the fixed tissue macrophage system. Thus the phenotypic and pathologic alterations in gus(mps2J)/gus(mps2J) mice are similar to those in patients with mucopolysaccharidosis VII. The finding of antibodies to beta-glucuronidase in some older gus(mps2J)/gus(mps2J) mice suggests the mice produce sufficient enzyme to elicit an immune response. The gus(mps2J)/gus(mps2J) model provides another well-defined genetic system for the study of the pathophysiology of mucopolysaccharidosis and for evaluation of experimental therapies for lysosomal storage diseases. The disease in gus(mps2J)/gus(mps2J) mice is less severe than that seen in the previously characterized B6.C-H2(bm1)/ByBir-gus(mps)/gus(mps) mouse model. Furthermore, unlike gus(mps)/gus(mps) mice, gus(mps2J)/gus(mps2J) mice are fertile and breed to produce litters, all of which are mucopolysaccharidosis VII pups. This feature makes them extremely useful for testing intrauterine therapies.

Active site mutant transgene confers tolerance to human beta-glucuronidase without affecting the phenotype of MPS VII mice

Mucopolysaccharidosis type VII (MPS VII; Sly syndrome) is an autosomal recessive lysosomal storage disorder due to an inherited deficiency of beta-glucuronidase. A naturally occurring mouse model for this disease was discovered at The Jackson Laboratory and shown to be due to homozygosity for a 1-bp deletion in exon 10 of the gus gene. The murine model MPS VII (gus(mps/mps)) has been very well characterized and used extensively to evaluate experimental strategies for lysosomal storage diseases, including bone marrow transplantation, enzyme replacement therapy, and gene therapy. To enhance the value of this model for enzyme and gene therapy, we produced a transgenic mouse expressing the human beta-glucuronidase cDNA with an amino acid substitution at the active site nucleophile (E540A) and bred it onto the MPS VII (gus(mps/mps)) background. We demonstrate here that the mutant mice bearing the active site mutant human transgene retain the clinical, morphological, biochemical, and histopathological characteristics of the original MPS VII (gus(mps/mps)) mouse. However, they are now tolerant to immune challenge with human beta-glucuronidase. This "tolerant MPS VII mouse model" should be useful for preclinical trials evaluating the effectiveness of enzyme and/or gene therapy with the human gene products likely to be administered to human patients with MPS VII.

Placental pathology for the surgical pathologist

Pathologic examination of the placenta is of clinical importance in the evaluation of pregnancies with a less than perfect outcome. Morphologic alterations of the placenta can mirror disorders of the fetus and the mother and evaluation of the placenta can identify clinically significant lesions, allow understanding of a child's disability and may have a role in resolving medical-legal disputes. Pathologic findings in the placenta can provide information on the pathogenesis of cerebral palsy, mental retardation, or neurodevelopmental disorders. This review will cover a variety of frequently encountered, clinically important, and morphologically distinct disorders of the placenta. The current understanding of the clinical implications of lesions for the mother, infant, and for future pregnancies will also be considered.

Clinical and pathologic findings in two new allelic murine models of polycystic kidney disease

Patients with inherited cystic kidney diseases have progressive cystic dilation of nephrons with concomitant loss of functional renal parenchyma and renal failure. Animal models of inherited cystic kidney disease are useful for study of the pathogenesis and molecular basis of cystic renal diseases. This article describes the clinical and pathologic features in two spontaneously occurring murine models of inherited polycystic kidney disease due to independent allelic mutations on mouse chromosome 8. The mutations, designated kat and kat2J, affect a chromosomal segment homologous to a region of human chromosome 4q35; the altered gene has not yet been identified. An allelism test showed that the mutations are at the same locus. The phenotype, inherited as an autosomal recessive, is more severe in kat2J/kat2J mice. Their kidneys are morphologically normal at birth, but by 3 mo of age, cysts affect all levels of the nephron. Adult males have testicular hypoplasia and they are sterile. A few of the oldest kat2J/kat2J mice have focal portal bile duct proliferation and dilation. kat2J/kat2J mice develop anemia and uremia and die before 1 yr of age. In kat/kat mice, the renal cystic disease progresses more slowly but is morphologically similar to that of kat2J/kat2J mice. The progressive cystic transformation of the kidneys in these allelic murine models resembles that seen in humans with autosomal dominant polycystic kidney disease.

Enzyme replacement in murine mucopolysaccharidosis type VII: neuronal and glial response to beta-glucuronidase requires early initiation of enzyme replacement therapy

We have previously shown that mucopolysaccharidosis type VII (MPS VII) mice receiving six weekly injections of recombinant beta-glucuronidase from birth had improved cognitive ability and reduced central nervous system lysosomal storage. However, a single beta-glucuronidase injection at 5 wk of age did not correct neuronal storage. We define the age at which central nervous system storage in MPS VII mice becomes resistant to beta-glucuronidase therapy and determine the effect of enzyme on other tissues by comparing the histology of mice begun on therapy at various times after birth. MPS VII mice received injections on the day of birth and then weekly for 5 wk with 16,000U/g beta-glucuronidase had reduced lysosomal storage in brain. The same therapy begun on d 14 of life or thereafter failed to correct neuronal storage, even when treatment was continued for six doses. Glial responsiveness or accessibility to enzyme also depended on early treatment. In contrast, leptomeningeal, osteoblast, and retinal pigment epithelial storage reduction depended on enzyme dose rather than age at initiation of therapy. Fixed tissue macrophage storage was reduced in all treated MPS VII mice, even those receiving a single dose. These observations indicate that fixed tissue macrophages in MPS VII mice remain sensitive to enzyme replacement therapy well into adulthood although neurons are responsive or accessible to enzyme therapy early in life. Because early initiation of enzyme replacement is important to achieve a central nervous system response, these studies emphasize the importance of newborn screening for lysosomal storage diseases so that early treatment can maximize the likelihood of a favorable therapeutic response.

Glomerular membranopathy in children with IgA nephropathy and Henoch Schönlein purpura

We evaluated renal biopsies from 34 children with IgA nephropathy or Henoch Schönlein purpura to further characterize the ultrastructural features of the glomerular membranopathy that occurs in these disorders. Focal glomerular basement membrane damage was identified in 29 children and was severe in 4 of the children. Alterations included focal and segmental attenuation, splitting, duplications, and spike-like subepithelial protrusions of the lamina densa, along with saccular glomerular microaneurysms arising at the paramesangium. Those cases with extensive glomerular basement membrane lesions had either moderate or severe glomerular alterations apparent by light microscopy. Over half of the cases with glomerular membranopathy had immunohistological or ultrastructural evidence of focal peripheral glomerular capillary wall immune deposits and electron-dense deposits occurred at sites of glomerular basement membrane splitting. Despite the focal attenuation of the glomerular basement membrane, we did not identify any biopsy with findings of thin basement membrane disease. The glomerular basement membrane ultrastructural findings we describe are characteristic of IgA nephropathy and Henoch Schönlein purpura, are common in children with these disorders, and are similar to the ultrastructural alterations of the basement membrane that occur in other glomerulonephritides. These basement membrane injuries may be inflammatory cell or immune mediated but their pathogenesis requires further study.

Inhibitory and excitatory responses of olfactory receptor neurons of xenopus laevis tadpoles to stimulation with amino acids

Recordings were made from olfactory receptor neurons of Xenopus laevis tadpoles using the patch-clamp technique to investigate the responses of these cells to odorants. Four amino acids (glutamate, methionine, arginine and alanine) both individually and as a mixture were used as stimuli. Of the 156 olfactory neurons tested, 43 showed a response to at least one of the stimuli. Of the cells tested, 19 % responded to glutamate, 16 % to methionine, 12 % to arginine and 10 % to alanine. Each amino acid was able to induce both excitatory and inhibitory responses, although these occurred in different cells. Each amino acid produced approximately equal numbers of inhibitory and excitatory responses. Inhibitory responses could best be observed in the perforated-patch configuration using gramicidin as an ionophore and a recording configuration that is a current-clamp for fast signals and a voltage-clamp for slow signals. The diversity of the odorant responses, in particular the existence of excitatory and inhibitory responses, is not consistent with a single transduction pathway in olfactory neurons of Xenopus laevis tadpoles.

Neonatal gene transfer leads to widespread correction of pathology in a murine model of lysosomal storage disease

For many inborn errors of metabolism, early treatment is critical to prevent long-term developmental sequelae. We have used a gene-therapy approach to demonstrate this concept in a murine model of mucopolysaccharidosis type VII (MPS VII). Newborn MPS VII mice received a single intravenous injection with 5.4 x 10(6) infectious units of recombinant adeno-associated virus encoding the human beta-glucuronidase (GUSB) cDNA. Therapeutic levels of GUSB expression were achieved by 1 week of age in liver, heart, lung, spleen, kidney, brain, and retina. GUSB expression persisted in most organs for the 16-week duration of the study at levels sufficient to either reduce or prevent completely lysosomal storage. Of particular significance, neurons, microglia, and meninges of the central nervous system were virtually cleared of disease. In addition, neonatal treatment of MPS VII mice provided access to the central nervous system via an intravenous route, avoiding a more invasive procedure later in life. These data suggest that gene transfer mediated by adeno-associated virus can achieve therapeutically relevant levels of enzyme very early in life and that the rapid growth and differentiation of tissues does not limit long-term expression.

Neonatal intramuscular injection with recombinant adeno-associated virus results in prolonged beta-glucuronidase expression in situ and correction of liver pathology in mucopolysaccharidosis type VII mice

For many metabolic diseases, early correction of the inherited deficiency is required to prevent long-term sequelae. We examined the ability of adeno-associated virus (AAV) to mediate efficient gene transfer during the neonatal period in mice with the lysosomal storage disease mucopolysaccharidosis type VII (MPS VII). Quadriceps of newborn MPS VII mice were injected with an AAV vector containing human beta-glucuronidase (GUSB) cDNA. High-level intramuscular GUSB expression was seen as early as 2 weeks of age, and persisted for at least 16 weeks with no reduction in activity. In addition, GUSB activity was detected in both liver and spleen at later time points. The level of GUSB activity resulted in a significant reduction in lysosomal storage in the liver and a minimal reduction in the spleen at 16 weeks. However, the temporal and spatial pattern of hepatic GUSB activity, coupled with the presence of GUSB cDNA in liver sections, suggests that hematogenous dissemination of virus at the time of injection led to gene transfer to hepatic cells. These results demonstrate that AAV vectors can successfully infect neonatal muscle and persist through the rapid growth phase following birth. However, GUSB secretion from an intramuscular source is inefficient, limiting the therapeutic efficacy of this approach.

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.

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.

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.

Adenovirus-mediated gene transfer and expression of human beta-glucuronidase gene in the liver, spleen, and central nervous system in mucopolysaccharidosis type VII mice

Mucopolysaccharidosis type VII (Sly syndrome) is a lysosomal storage disease caused by inherited deficiency of the lysosomal enzyme beta-glucuronidase. A murine model of this disorder has been well characterized and used to study a number of forms of experimental therapies, including gene therapy. We produced recombinant adenovirus that expresses human beta-glucuronidase and administered this recombinant adenovirus to beta-glucuronidase-deficient mice intravenously. The beta-glucuronidase activities in liver and spleen were elevated to 40% and 20%, respectively, of the heterozygote enzymatic level at day 16. Expression persisted for at least 35 days. Pathological abnormalities of these tissues were also improved, and the elevated levels of urinary glycosaminoglycans were reduced in treated mice. However, the beta-glucuronidase activity in kidney and brain was not significantly increased. After administration of the recombinant adenovirus directly into the lateral ventricles of mutant mice, the beta-glucuronidase activity in crude brain homogenates increased to 30% of heterozygote activity. Histochemical demonstration of beta-glucuronidase activity in brain revealed that the enzymatic activity was mainly in ependymal cells and choroid. However, in some regions, the adenovirus-mediated gene expression was also evident in brain parenchyma associated with vessels and in the meninges. These results suggest that adenovirus-mediated gene delivery might improve the central nervous system pathology of mucopolysaccharidosis in addition to correcting visceral pathology.

Neuropathology of murine mucopolysaccharidosis type VII

We describe the neuropathology in mucopolysaccharidosis type VII (MPS VII) mice with a recessively inherited deficiency of the lysosomal enzyme beta-glucuronidase. Affected animals have a shortened life span, are dysmorphic, dwarfed and have clinical evidence of behavioral and memory deficiencies. Widespread lysosomal distention with glycosaminoglycan accumulation affects most viscera. In the central nervous system there is progressive accumulation of lysosomal storage in neurons, glia and mesenchymal tissue. The morphological character and the amount of lysosomal storage varies among neuronal groups. In the hippocampus, regional variation in the abundance of lysosomal storage in the MPS VII mice correlates with regional variation in the amount of beta-glucuronidase activity in normal mice. The MPS VII mouse provides a well-defined genetic system for the analysis of the neuropathology of MPS VII and is an attractive model on which to test the effects of potential therapies for lysosomal storage disease on the central nervous system.

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.

Microangiopathic glomerulopathy in children with sickle cell anemia

We studied kidney biopsy specimens from three children with sickle cell anemia and microangiopathic glomerulopathy. One child also had cyanotic congenital heart disease. Laboratory evaluation revealed proteinuria and normal serum creatinine in all and normal serum complement in two of the three children at the time of biopsy. In all biopsies, glomeruli were enlarged with diffuse hypercellularity and focal segmental mesangial interposition; capillary loop lumens were congested with sickled erythrocytes. Immune labeling identified segmental immunoglobulin G, C3, and properdin over the glomerular capillary loop walls in each case. Ultrastructurally, the subendothelial zone of the glomerular basement membrane was widened with new lamina densa formation with focal mesangial interposition. The glomerular lesion we describe in these children may be due to endothelial injury related to the altered erythrocytes, glomerular hemodynamics, and the hypercoagulable state characteristic of sickle cell disease.

The inflammatory response in pediatric biliary disease: macrophage phenotype and distribution

PURPOSE

Extrahepatic biliary obstruction in infants and children leads to ductal hyperplasia and portal fibrosis. Inflammatory mediators responsible for increased cellular proliferation and matrix deposition are hypothesized to result from the intrahepatic recruitment and activation of lymphocytes and macrophages (M phi). The authors previously showed components of this mechanism in studies that demonstrated increased adhesion molecule expression in biliary atresia, as well as evidence of altered hepatic M phi function during the course of experimental cholestatic liver injury. Therefore they sought determine the expression of macrophage receptor markers CD68 and CD14 in pediatric biliary disease.

METHODS

Sixteen liver specimens were snap-frozen and cryosectioned onto polylysine-coated slides. Sections were stained with murine monoclonal antibodies to CD68 (resident M phi) and CD14 (monocyte-M phi lipopolysaccharide [LPS] receptor) glycoproteins. The sections were analyzed using a semiquantitative scale of proliferation and were position-graded from 0 to 3 (maximal).

RESULTS

Blinded analysis showed that marked proliferation of CD68-positive cells occurred in five of the six patients with biliary atresia (BA) and in one patient who had severe cholestasis. Normal perisinusoidal liver M phi were found in specimens from patients with hepatitis (2), choledochal cyst (1), and congenital hepatic fibrosis (1). Similarly, expression of CD14 periportal M phi was found only in patients with BA or cholestasis (1.9 +/- 0.3 [mean +/- SEM]) and was absent in other diseases. Strong sinusoidal expression of CD14 was evident in all patients who had extrahepatic biliary obstruction. An early biopsy specimen from a premature infant with BA did not show cholestasis, fibrosis, CD68 Mø proliferation, or CD14 expression; however, another biopsy specimen, obtained further in the course of jaundice showed the progressive development of all features.

CONCLUSION

These findings suggest proliferation of resident M phi in association with cholestasis. The presence of the LPS receptor on periportal cells during cholestatic liver injury points to a potential source of cytokines responsible for the inflammatory reaction of biliary atresia.

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.

Expression of proliferating cell nuclear antigen in Spitz nevus

BACKGROUND

Epithelioid and spindle cell nevus (ESN; Spitz nevus) is a histologically well-described entity. We hypothesized that the features of ESN may reflect activation by a proliferative stimulus.

OBJECTIVE

Nevocytes and keratinocytes in ESN and control specimens were examined for expression of the proliferation marker, proliferating cell nuclear antigen (PCNA).

METHODS

Standard immunohistochemical methods were used to examine the expression of PCNA in a series of ESN, other nevi, and malignant melanoma.

RESULTS

PCNA was detected in nevocytes in a significant percentage of ESN but not in other nevi. PCNA expression was increased in basilar keratinocytes in ESN when compared with staining of basilar keratinocytes in normal epidermis. In other melanocytic nevi and noninflamed melanoma, PCNA expression in keratinocytes was similar to that in normal control tissue.

CONCLUSION

Increased PCNA labeling in nevocytes and keratinocytes in ESN suggests that a growth stimulus, present within some of these lesions, affects both keratinocytes and nevocytes.

Pathology of the ear in murine mucopolysaccharidosis type VII. Morphologic correlates of hearing loss

BACKGROUND

Patients with mucopolysaccharidosis commonly have hearing impairment but the morphologic alterations in the ear caused by these lysosomal storage diseases are incompletely defined.

EXPERIMENTAL DESIGN

We studied a murine model of mucopolysaccharidosis VII with clinical features, including conductive hearing loss and biochemical, and pathologic features similar to those seen in human mucopolysaccharidoses. Gross morphology, radiography, light and electron microscopy were used to define the pathologic alterations in the ear that correlate with auditory dysfunction in mucopolysaccharidosis VII.

RESULTS

Cerumen occluded the external auditory canal and there was a severe otitis media. The bone encasing the middle and inner ear was sclerotic and opaque and the temporal bone and the ossicles and their joints contained cells distended by enlarged lysosomes. Hair cell damage and multifocal lysosomal distention in endoneural fibroblasts and spiral ganglion neurons characterized the mucopolysaccharidosis VII cochlea.

CONCLUSIONS

The external auditory canal obstruction, otitis media, and ossicle articular alterations in mucopolysaccharidosis VII mice cause a conductive hearing loss. The hair cell damage and neuronal storage may contribute to sensorineural deafness. This model allows investigation of the pathophysiology of auditory dysfunction in mucopolysaccharidosis and the effects of therapies on hearing loss.

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.

Mucopolysaccharidosis VII: postmortem biochemical and pathological findings in a young adult with beta-glucuronidase deficiency

The postmortem biochemical and pathological findings in the first patient reported with mucopolysaccharidosis VII are described. Clinical, radiographic, and biochemical features of this 19-yr-old black man were initially reported in 1973 when, at age 2 1/2 yr his enzymatic defect, deficiency of beta-glucuronidase, was identified. The autopsy findings are now described with biochemical data further characterizing the enzyme deficiency and resultant glycosaminoglycan accumulation. He had dysostosis multiplex and extensive cardiovascular lesions including arterial stenosis, and marked fibrous thickening of the atrioventricular and aortic valves. Microscopic evidence of lysosomal storage was found in bone, cartilage, arteries and cardiac valves, liver, spleen, lymph nodes, eyes, adrenal, pituitary, and the central nervous system. In the brain, storage was localized to specific regions, primarily intraneuronal, and appeared ultrastructurally as delicate whorled filamentous accumulations in lysosomes. Similar filamentous storage also occurred in medial cells of the aorta. Multiple postmortem tissues contained only trace amounts of beta-glucuronidase and elevated glycosaminoglycans, predominantly chondroitin 4- and 6-sulfate.

Enzyme replacement with recombinant beta-glucuronidase in the newborn mucopolysaccharidosis type VII mouse

beta-Glucuronidase injected i.v. into newborn mucopolysaccharidosis VII mice was cleared from the circulation in less than 1 h and taken up by tissues in a distribution corresponding to the location of the mannose 6-phosphate receptor. One h after a 3.5-mg/kg beta-glucuronidase injection, beta-glucuronidase levels were equal to or greater than normal in every organ examined with the exception of the brain, where 31% normal activity was present. Enzyme was detectable histochemically in the major sites of pathology for mucopolysaccharidosis VII including bone, brain, heart, and fixed tissue macrophages. The half-life of recombinant beta-glucuronidase activity in various organs of injected mucopolysaccharidosis VII mice was 1.5 to 4.5 d. These studies show that recombinant beta-glucuronidase administered to newborn mice reaches the sites of clinically important storage in murine mucopolysaccharidosis VII.

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.

Role of influenza B virus in hepatic steatosis and mitochondrial abnormalities in a mouse model of Reye syndrome

The hepatic steatosis observed in the influenza B virus mouse model of Reye syndrome has been attributed to infectious virus or, alternately, to decreased food intake in the virus-treated mice or impurities in the virus preparation. To resolve this issue, 4- to 6-wk-old male Balb C mice were given, by intravenous injection, 12,800 hemagglutination units of influenza B Lee/40 virus in phosphate buffered saline/1% bovine serum albumin using virus prepared by ultra-centrifugation from infected allantoic fluid, by sucrose density-gradient purification of virus prepared by ultracentrifugation from infected allantoic fluid or by irradiation of virus prepared by ultracentrifugation from infected allantoic fluid to inactivate virus. The infectivity titer of virus prepared by ultracentrifugation from infected allantoic fluid was much higher than that of sucrose density-gradient purified virus prepared from infected allantoic fluid: 50% egg infectious dose for virus prepared by ultracentrifugation from infected allantoic fluid was 3.9 x 10(4)/hemagglutination unit vs. 8.7 50% egg infectious dose/hemagglutination unit for sucrose density-gradient purified virus prepared from infected allantoic fluid. Control mice received phosphate-buffered saline/1% bovine serum albumin or uninfected allantoic fluid diluted in phosphate-buffered saline/1% bovine serum albumin. Mice were fasted to eliminate dietary variation, and livers were obtained 36 hr after virus administration. Of the above treatments, only virus prepared by ultracentrifugation from infected allantoic fluid caused clinical illness and increased hepatic triglycerides (p less than 0.02) compared with controls. Hepatic triglycerides in virus prepared by ultracentrifugation from infected allantoic fluid correlated with histopathological vacuolization scores (r = 0.5773; p less than 0.03).(ABSTRACT TRUNCATED AT 250 WORDS)

Focal mucinosis of the upper aerodigestive tract in children

Cutaneous mucinosis is an uncommon lesion characterized by mucin accumulation in the dermis. Rarely, mucinosis may arise in the oral cavity; reported cases have been observed in patients older than 16 years. We identified two children younger than 5 years of age with focal mucinosis of the upper aerodigestive tract. A 3-year-old boy had been intubated at age 2 months, suffered from recurrent respiratory infections, and developed mucinosis of the larynx, a previously unreported site for this unusual lesion. The second patient, a 4-year-old girl with a cleft palate, developed palatine mucinosis.

Acridine orange--RNA histofluorescence of sarcomas and small round cell tumors of childhood

Forty-nine pediatric malignant neoplasms were stained with acridine orange (AO) fluorochrome to qualitatively evaluate cytoplasmic RNA content. The application of AO as a supplementary stain in surgical pathologic diagnosis is based on the premise that specific neoplastic cell types characteristically and consistently contain few or many cytoplasmic ribosomes. Primitive tumors such as Ewing's sarcoma and primitive neuroectodermal tumors showed negative or low-intensity AO-RNA cytoplasmic staining. Differentiated sarcomas such as rhabdomyosarcomas and lymphomas exhibited moderate to strong AO-RNA cytoplasmic fluorescence. Acridine orange--RNA staining provides an easy, convenient, and inexpensive adjunct in the histopathologic differential diagnosis of sarcomas. It is particularly useful for distinguishing Ewing's sarcomas from other small round cell sarcomas of childhood.

Correction of murine mucopolysaccharidosis VII by a human beta-glucuronidase transgene

We recently described a murine model for mucopolysaccharidosis VII in mice that have an inherited deficiency of beta-glucuronidase (beta-D-glucuronoside glucuronosohydrolase, EC 3.2.1.31). Affected mice, of genotype gusmps/gusmps, present clinical manifestations similar to those of humans with mucopolysaccharidosis VII (Sly syndrome) and are shown here to have secondary elevations of other lysosomal enzymes. The mucopolysaccharidosis VII phenotype in both species includes dwarfism, skeletal deformities, and premature death. Lysosome storage is visualized within enlarge vesicles and correlates biochemically with accumulation of undegraded and partially degraded glycosaminoglycans. In this report we describe the consequences of introducing the human beta-glucuronidase gene, GUSB, into gusmps/gusmps mice that produce virtually no murine beta-glucuronidase. Transgenic mice homozygous for the mucopolysaccharidosis VII mutation expressed high levels of human beta-glucuronidase activity in all tissues examined and were phenotypically normal. Biochemically, both the intralysosomal storage of glycosaminoglycans and the secondary elevation of other acid hydrolases were corrected. These findings demonstrate that the GUSB transgene is expressed in gusmps/gusmps mice and that human beta-glucuronidase corrects the murine mucopolysaccharidosis storage disease.

A murine model of mucopolysaccharidosis VII. Gross and microscopic findings in beta-glucuronidase-deficient mice

This report describes the clinical and pathologic alterations found in mice that have a recessively inherited, essentially complete deficiency of the lysosomal enzyme beta-glucuronidase. Affected animals have a shortened life span and are dysmorphic and dwarfed. Abnormal gait and decreased joint mobility correlate with glycosaminoglycan accumulation in articular tissue and cartilaginous and bony lesions result in extensive skeletal deformation. In these enzyme-deficient animals, lysosomes, distended by fine fibrillar and granular storage material, are particularly prominent in the macrophage system but also occur in other tissues including the skeletal and central nervous systems. The clinical and pathologic abnormalities in these mutant mice closely parallel those identified in humans with mucopolysaccharidoses (MPS). Therefore, these mice provide a well-defined genetic system for the analysis of the pathophysiology of mucopolysaccharidosis type VII, which has many features in common with the other MPS. The mutant mice provide an attractive animal model to test potential therapies for lysosomal storage disease.