A method to accurately inject tumor cells into the caudate/putamen nuclei of the mouse brain

OBJECTIVE

To improve currently used techniques to implant tumor cells into the parenchyma of the mouse brain.

MATERIALS AND METHODS

The stereotactic injection of 0.5 to 5 microl of indigo carmine over 5 to 40 minutes into the caudate/putamen nuclei of the mouse was done followed by sacrifice and examination of the brain injection site. 1 microl containing 10(5) U87MG glioma cells were stereotactically implanted into the caudate/ putamen nuclei over 20 minutes. The animals were sacrificed from one hour to 63 days after implantation and the brain examined and tumor size measured.

RESULTS

An injection of 1 microl of indigo carmine over 20 minutes produced a spherical deposit of dye within the caudate/putamen nuclei. Larger volumes of indigo carmine or shorter injection times resulted in dye spreading along the injection tract or into the ventricles or subarachnoid space. Using the results of the dye studies, the same parameters were used to successfully inject and confine the glioma cells to the caudate/putamen nuclei in 30 of 32 mice. No tumor was found in 2 animals and appears to be explained by obstruction of the injection cannula. The tumor cells appeared viable an hour after injection. However by day three, considerable necrosis of tumor cells were noted, the effects of which resolved by day five. On day six, the injection site was comparable to that at one hour. In the early phase, until the fifth week, tumor volume doubling time was ten days while afterward it was only five days.

CONCLUSION

The technique described allows the highly accurate and reproducible introduction of a given number of cells into a specific area of the mouse brain. This should reduce the intragroup variability, be it control or therapeutic, allowing better assessment of outcome with fewer number of mice.

Low-affinity nerve growth factor receptor p75NTR immunoreactivity in the myocardium with sympathetic hyperinnervation

INTRODUCTION

We previously demonstrated the relationship between sympathetic nerve density in myocardium and the occurrences of ventricular arrhythmia. Nerve growth factor (NGF) regulates myocardial sympathetic innervation. However, it is unclear whether the NGF high-affinity receptor tyrosine kinase A (TrkA) and the NGF low-affinity receptor p75NTR are altered in the state of sympathetic hyperinnervation in the heart. The aim of this study was to determine the density and location of TrkA and p75NTR in canine ventricles with sympathetic hyperinnervation.

METHODS AND RESULTS

Myocardial sympathetic hyperinnervation was induced by local infusion of NGF into myocardium or left stellate ganglia, or chronic subthreshold electric stimulation to the left stellate ganglia. The results showed that TrkA immunoreactivity was absent in the myocardium. Low-affinity receptor p75NTR immunoreactivity was present in axons, Schwann cells, and interstitial cells of sympathetic nerves, as well as in interstitial cells of the myocardium. The density of p75NTR immunolabeled myocardial interstitial cells at the NGF infusion site was lower than that at the site remote from NGF infusion, yet the sympathetic nerve density was higher at the infusion site than the remote area. The density of p75NTR also was lower in the myocardium with high sympathetic nerve density, induced by NGF infusion or chronic electric stimulation of the left stellate ganglia, compared to control groups.

CONCLUSION

The data indicate that p75NTR may be the main NGF receptor in the myocardium, and p75NTR immunopositive interstitial cells may have a role in regulating sympathetic nerve growth in canine heart.

Micro-MRI at 11.7 T of a murine brain tumor model using delayed contrast enhancement

In vivo imaging methodologies allow for serial measurement of tumor size, circumventing the need for sacrificing mice at given time points. In orthotopically transplanted murine models of brain tumors, cross-section micro-MRI allows for visualization and measurement of the physically inaccessible tumors. To allow for long resident times of a contrast agent in the tumor, intraperitoneal administration was used as a route of injection for contrast-enhanced micro-MRI, and a simple method for relative tumor volume measurements was examined. A strategy for visualizing the variability of the delayed tumor enhancement was developed. These strategies were applied to monitor the growth of brain tumors xenotransplanted into nude mice and either treated with the antiangiogenic peptide EMD 121974 or an inactive control peptide. Each mouse was used as its own control. Serial imaging was done weekly, beginning at Day 7 after tumor cell implantation and continued for 7 weeks. Images obtained were reconstructed on the MRI instrument. The image files were transferred off line to be postprocessed to assess tumor growth (volume) and variability in enhancement (three-dimensional [3-D] intensity models). In a small study, tumor growth and response to treatment were followed using this methodology and the high-resolution images displayed in 3-D allowed for straightforward qualitative assessment of variable enhancement related to vascular factors and tumor age.

Abducens length and vulnerability?

BACKGROUND

Several sources have attributed the vulnerability of the abducens nerve to its long intracranial course. However, other anatomic factors likely contribute to the apparent vulnerability of the abducens nerve to mass lesions and trauma.

METHODS

The authors performed a two-part anatomic study of the abducens nerve. In the first part of the study, they compared the length of the abducens with another cranial nerve, the trochlear, at the autopsy of 26 pediatric patients. In the second part of the study, the authors used an endoscopic exposure of these two cranial nerves in a preserved human cadaver head.

RESULTS

The abducens nerve was consistently approximately one-third the length of the trochlear nerve at all ages that they studied. The endoscopic views revealed the structural and vascular relationships of the abducens nerve in situ.

CONCLUSIONS

The authors conclude from these findings and the literature that abducens nerve vulnerability results from factors other than its intracranial length.

Long-term subthreshold electrical stimulation of the left stellate ganglion and a canine model of sudden cardiac death

OBJECTIVES

We sought to develop a high-yield canine model of sudden cardiac death (SCD).

BACKGROUND

Because electrical stimulation is a powerful means to elicit nerve sprouting, we hypothesize that subthreshold electrical stimulation is more effective than nerve growth factor (NGF) infusion in inducing nerve sprouting and SCD in dogs with myocardial infarction (MI) and complete atrioventricular block (CAVB).

METHODS

We gave subthreshold electrical stimulation to the left stellate ganglion (LSG) in six normal dogs for 41 +/- 9 days (protocol 1) and to six dogs with MI and CAVB for 41 +/- 29 days, while continuously monitoring their cardiac rhythm (protocol 2). We also monitored the rhythm of two dogs with MI, CAVB, and NGF infusion to the LSG and determined the ventricular nerve density in six healthy control dogs.

RESULTS

In protocol 1, the hearts from dogs with LSG electrical stimulation had a higher density of nerve fibers immunopositive to tyrosine hydroxylase, synaptophysin, and growth-associated protein-43 than those of normal control dogs (p < 0.01). In protocol 2, there was a high magnitude of cardiac nerve sprouting in all dogs studied. Ventricular tachycardia > or =8 beats and > or =20 beats was more frequent in dogs with electrical stimulation than in dogs with NGF infusion to the LSG (36 +/- 60 and 11 +/- 17 vs. 4.7 +/- 6.1 and 0.1 +/- 0.33 episodes per day, p < 0.05 and p < 0.03, respectively). Four of six dogs in protocol 2 had SCD.

CONCLUSIONS

Subthreshold electrical stimulation of the LSG induces cardiac nerve sprouting and sympathetic hyperinnervation and facilitates the development of a high-yield canine model of ventricular arrhythmia and SCD.

Pilomatrixoma:

Pilomatrixoma, also known as calcifying epithelioma of Malherbe, is a benign skin neoplasm that arises from hair follicle matrix cells. Pilomatrixoma is a common skin neoplasm in the pediatric population that is often misdiagnosed as other skin conditions. This study reviews an 11-year experience at a tertiary children's hospital, examining the cause, clinical and histopathological presentation, management, and treatment outcomes of pilomatrixoma. A review of the pathology database at Children's Hospital Los Angeles revealed 346 pilomatrixomas excised from 336 patients between 1991 and 2001. The hospital charts, pathology records, and plastic surgery clinic charts were reviewed with respect to variables such as sex, age at the time of presentation, clinical and histopathological presentation, preoperative diagnosis, management, recurrence, and treatment outcome. The main presenting symptom was a hard, subcutaneous, slowly growing mass. The preoperative diagnosis was accurate and consistent with the pathological diagnosis of pilomatrixoma in only 100 cases (28.9 percent). This entity should be considered with other benign or malignant conditions in the clinical differential diagnosis of solitary firm skin nodules, especially those on the head, neck, or upper limbs. The diagnosis can generally be made with a clinical examination. Imaging studies are not required unless symptoms or the location of the lesion warrants such diagnostic assessments. The treatment of choice is surgical excision, and the recurrence rate is low.

Targeted Expression of Activated Rac3 in Mammary Epithelium Leads to Defective Postlactational Involution and Benign Mammary Gland Lesions

Rac3, a novel member of the Rho subfamily of the small GTPases, is frequently activated in cultured breast cancer cells and has been shown to mediate its effect via the p21-activated kinase (Pak) pathway. In order to evaluate these findings in vivo, we generated transgenic mice that express human constitutively active V12Rac under the control of the mouse mammary tumor virus (MMTV) promoter, which targets the transgene expression to the mammary epithelium. V12Rac3 expression could be detected during the first pregnancy, and the transgenic mammary gland tissues displayed an elevated Pak1 phosphorylation. Although milk proteins, beta-casein and whey acidic protein were expressed and milk fat globules accumulated normally during pregnancy, 60% of transgenic mothers failed to nurse their pups. Surprisingly, although full lactational differentiation was never achieved in transgenic mice, gland involution was incomplete. For 5 days after weaning, involution was normal, but thereafter, epithelial islands characteristic of this early stage of involution persisted for months. The apoptotic index decreased after 5 days, and these glands were associated with increased p38 MAPK phosphorylation. Nine months postpartum, the transgenic mammary glands still demonstrated a large amount of persistent epithelial islands and abnormally large ducts with lymphocyte infiltration, whereas the tissues of non-transgenic controls had returned to their normal 'virgin-like' phenotype. These data show that sustained activation of Rac3 in the mammary epithelium leads to impaired mammary gland physiology and results in the formation of mammary gland lesions.

Citrobacter koseri brain abscess in the neonatal rat: survival and replication within human and rat macrophages

A unique feature of Citrobacter koseri is the extremely high propensity to initiate brain abscesses during neonatal meningitis. Previous clinical reports and studies on infant rats have documented many Citrobacter-filled macrophages within the ventricles and brain abscesses. It has been hypothesized that intracellular survival and replication within macrophages may be a mechanism by which C. koseri subverts the host response and elicits chronic infection, resulting in brain abscess formation. In this study, we showed that C. koseri causes meningitis and brain abscesses in the neonatal rat model, and we utilized histology and magnetic resonance imaging technology to visualize brain abscess formation. Histology and electron microscopy (EM) revealed that macrophages (and not fibroblasts, astrocytes, oligodendrocytes, or neurons) were the primary target for long-term C. koseri infection. To better understand C. koseri pathogenesis, we have characterized the interactions of C. koseri with human macrophages. We found that C. koseri survives and replicates within macrophages in vitro and that uptake of C. koseri increases in the presence of human pooled serum in a dose-dependent manner. EM studies lend support to the hypothesis that C. koseri uses morphologically different methods of uptake to enter macrophages. FcgammaRI blocking experiments show that this receptor primarily facilitates the entry of opsonized C. koseri into macrophages. Further, confocal fluorescence microscopy demonstrates that C. koseri survives phagolysosomal fusion and that more than 90% of intracellular C. koseri organisms are colocalized within phagolysosomes. The ability of C. koseri to survive phagolysosome fusion and replicate within macrophages may contribute to the establishment of chronic central nervous system infection including brain abscesses.

Micro-MRI at 11.7 T of a Murine Brain Tumor Model Using Delayed Contrast Enhancement

In vivo imaging methodologies allow for serial measurement of tumor size, circumventing the need for sacrificing mice at given time points. In orthotopically transplanted murine models of brain tumors, cross-section micro-MRI allows for visualization and measurement of the physically inaccessible tumors. To allow for long resident times of a contrast agent in the tumor, intraperitoneal administration was used as a route of injection for contrast-enhanced micro-MRI, and a simple method for relative tumor volume measurements was examined. A strategy for visualizing the variability of the delayed tumor enhancement was developed. These strategies were applied to monitor the growth of brain tumors xenotransplanted into nude mice and either treated with the antiangiogenic peptide EMD 121974 or an inactive control peptide. Each mouse was used as its own control. Serial imaging was done weekly, beginning at Day 7 after tumor cell implantation and continued for 7 weeks. Images obtained were reconstructed on the MRI instrument. The image files were transferred off line to be postprocessed to assess tumor growth (volume) and variability in enhancement (three-dimensional [3-D] intensity models). In a small study, tumor growth and response to treatment were followed using this methodology and the high-resolution images displayed in 3-D allowed for straightforward qualitative assessment of variable enhancement related to vascular factors and tumor age.

Use of elemental iodine for shunt infection prophylaxis

OBJECTIVE

Elemental iodine (I(2)) can kill a broad spectrum of organisms, including bacteria, fungi, and viruses. Furthermore, it is inexpensive, bacterial resistance is unknown, and allergic reactions are rare. Because of these properties, we wanted to determine the concentration of I(2) that would kill Staphylococcus epidermidis and Staphylococcus aureus without causing injury to the central nervous system, in an attempt to further reduce the rates of shunt infections.

METHODS

Bacterial kill studies using S. epidermidis and S. aureus were performed by using Ringer's lactate solution alone or solution containing I(2) at a concentration of 5, 10, 20, 50, 100, or 1000 parts per million (ppm), cefazolin at 1 mg/ml, or bacitracin at 100 units/ml. Twenty-one adult male Wistar rats, in seven groups, underwent a frontoparietal craniectomy. The surfaces of their brains were irrigated for 1 hour with Ringer's lactate solution alone or solution containing I(2) (at the concentrations noted above). After 72 hours of observation, the animals were killed. Their brains were then fixed in formalin, stained with hematoxylin/eosin, and examined.

RESULTS

Even with exposure of only 15 seconds to an I(2) solution of 20 ppm, no growth was detected with an inoculum of either bacteria of 100 million. In contrast, the two antibiotics were not nearly as effective as I(2), with kill rates ranging from 19 to 93%. Examination of the rat brains demonstrated no histological changes after subarachnoid exposure to solutions containing 5, 10, 20, or 50 ppm; however, necrosis was observed with concentrations of 100 and 1000 ppm.

CONCLUSION

I(2) can be added to irrigation solutions in sufficient concentrations to be bactericidal without causing any central nervous system injury.

In vitro and in vivo evaluations of the tyrosine kinase inhibitor NSC 680410 against human leukemia and glioblastoma cell lines

PURPOSE

NSC 680410, the novel adamantyl ester of AG957, an inhibitor of the p210bcr/abl tyrosine kinase (CML, Ph(+)) and possibly other kinases, was tested for antitumor activity in ten human leukemia and human glioblastoma cell lines.

METHODS

CEM/0, seven ara-C- and/or ASNase-resistant clones, Jurkat/0, the myelomonocytic line U937 and U87 MG glioblastoma cell lines were used for these studies. The drug-resistant leukemic clones lack p53, express bcl-2 and VEGF-R1, and thus are refractory to apoptosis. Since tyrosine kinases drive many proliferative pathways and these activities are increased in many leukemic cells, we hypothesized that NSC 680410 may induce cytotoxicity in drug-resistant leukemia clones, independently of p210bcr/abl expression.

RESULTS

NSC 680410 exhibited significant antileukemic activity in CEM/0, Jurkat E6-1, and in the drug-resistant leukemic cell lines. The IC(50) values in nine leukemia lines ranged from 17 to 216 n M. Western blot analyses after NSC 680410 treatment demonstrated caspase-3 cleavage and ELISAs showed a fivefold upregulation of its activity in cellular extracts. In addition, U87 MG human glioblastoma cells, which express VEGF-R1, were treated with the Flt-1/Fc chimera, a specific inhibitor of VEGF, and showed 30-43% cell kill in the MTT assay. Furthermore, the combination of NSC 680410 plus Flt-1/Fc chimera demonstrated an eightfold synergism against U87 MG cells in vitro. To verify this observation in vivo, athymic mice were inoculated orthotopically into the caudate putamen with 10(6) U87 MG cells. On day 3, five mice per group were treated i.p. with either 8.3 mg/kg NSC 680410 daily for three doses per week for 4 weeks alone or in combination with one dose of Flt-1/Fc chimera 100 mg/kg subcutaneously. Treatment with NSC 680410 alone produced no weight changes and increased the median survival to 133%, whereas treatment with NSC680410 plus Flt-1/Fc chimera increased survival to 142% over control. Control animals had large intra- and extracranial tumors while the NSC 680410-treated mice had small, only intracranial tumors with necrotic centers. The combination treatment resulted in small residual tumors around the needle track, indicating significant inhibition of tumor growth.

CONCLUSIONS

These studies demonstrate that the tyrosine kinase inhibitor NSC 680410 has significant antileukemic activity in p53-null, drug-resistant human leukemia cell lines, as well as significant antitumor activity in combination with Flt-1/Fc chimera against U87 MG glioblastoma brain tumors implanted in situ in athymic mice.

alpha v-Integrin antagonist EMD 121974 induces apoptosis in brain tumor cells growing on vitronectin and tenascin

Orthotopic brain tumor growth is inhibited in athymic mice by the daily systemic administration of the alpha v-integrin antagonist EMD 121974. This compound, a cyclic RGD-penta-peptide, is a potent inhibitor of angiogenesis, which induces apoptosis of growing endothelial cells through inhibition of their alpha v-integrin interaction with the matrix proteins vitronectin and tenascin. Here we show that EMD 121974 also induces apoptosis in the alpha v-integrin-expressing tumor cell lines U87 MG and DAOY by detaching them from vitronectin and tenascin, matrix proteins known to be essential for brain tumor growth and invasion. These matrix proteins are shown to be produced by the brain tumor cells in vitro and in vivo. Furthermore, only tumor cells expressing alpha v-integrins responded to the treatment with EMD 121974, after xenotransplantation into the forebrain of nude mice, supporting the importance of tumor cell-matrix interactions in tumor cell survival in the brain. Thus, the alpha v-antagonist EMD 121974 suppresses brain tumor growth through induction of apoptosis in both brain capillary and brain tumor cells by preventing their interaction with the matrix proteins vitronectin and tenascin. The dual action of this peptide explains its potent growth suppression of orthotopically transplanted brain tumors.

Vestibular dysgenesis in mice lacking Abr and Bcr Cdc42/RacGAPs

The inner ear develops from a simple epithelium (otic placode) into the complex structures specialized for balance (vestibule) and sound (cochlea) detection. Abnormal vestibular and cochlear development is associated with many birth defects. During recent years, considerable progress has been made in understanding the molecular bases of these conditions. To determine the biological function of two closely related GTPase activating proteins for the Cdc42/Rac GTPases, Abr and Bcr, we generated a mouse strain deficient in both of these proteins. Double null mutant mice exhibit hyperactivity, persistent circling, and are unable to swim. These phenotypes are typically found in mice with vestibular defects. Indeed, adult double null mutants display abnormal dysmorphic structures of both the saccule and utricle. Moreover, a total loss of otoconia can be seen in the utricle, whereas in the saccule, otoconia are either missing or their number is drastically decreased and they are abnormally large. Interestingly, both the cochlea and semicircular canals are normal and the double null mutant mice are not deaf. These data demonstrate that Abr and Bcr play important complementary roles during vestibular morphogenesis and that a function of Cdc42/RacGAPs and, therefore, that of the small Rho-related GTPases is critically important for balance and motor coordination.

Abnormal function of astroglia lacking Abr and Bcr RacGAPs

Experiments in cultured cells have implicated the molecular switch Rac in a wide variety of cellular functions. Here we demonstrate that the simultaneous disruption of two negative regulators of Rac, Abr and Bcr, in mice leads to specific abnormalities in postnatal cerebellar development. Mutants exhibit granule cell ectopia concomitant with foliation defects. We provide evidence that this phenotype is causally related to functional and structural abnormalities of glial cells. Bergmann glial processes are abnormal and GFAP-positive astroglia were aberrantly present on the pial surface. Older Abr;Bcr-deficient mice show spontaneous mid-brain glial hypertrophy, which can further be markedly enhanced by kainic acid. Double null mutant astroglia are hyper-responsive to stimulation with epidermal growth factor and lipopolysaccharide and exhibit constitutively increased phosphorylation of p38 mitogen-activated protein kinase, which is regulated by Rac. These combined data demonstrate a prominent role for Abr and Bcr in the regulation of glial cell morphology and reactivity, and consequently in granule cell migration during postnatal cerebellar development in mammals.

Mitochondrial DNA depletion, near-fatal metabolic acidosis, and liver failure in an HIV-infected child treated with combination antiretroviral therapy

A child with controlled human immunodeficiency virus infection presented with neurologic deterioration, lactic acidosis, and organic aciduria. Muscle biopsy revealed abnormal mitochondrial (mt) morphology, reduced mt enzyme activities, and mtDNA depletion. After adjustment of antiretroviral therapy to a regimen free of nucleoside analogs, marked improvement was seen in clinical status and mt abnormalities.

The Bcr N-terminal oligomerization domain contributes to the full oncogenicity of P190 Bcr/Abl in transgenic mice

The Bcr/Abl P190 oncoprotein is responsible for the development of Philadelphia-chromosome positive acute lymphoblastic leukemia (ALL). The Bcr moiety in Bcr/Abl activates the Abl tyrosine kinase, an ingredient essential for the transforming capability of Bcr/Abl. Residues 1-63 of Bcr form an N-terminal oligomerization domain and are key to Abl activation in vitro. Mice transgenic for P190 BCR/ABL reproducibly develop an aggressive B-lineage lymphoblastic leukemia/lymphoma. Here we test the hypothesis that residues 1-63 of Bcr have a major in vivo contribution to the oncogenicity of Bcr/Abl P190 by the generation of mice transgenic for an N-terminal deleted form of P190. We find that although the transgene is expressed in the bone marrow of mice at an early age, the incidence of leukemogenesis is greatly diminished as compared to mice transgenic for non-mutated P190 Bcr/Abl. Sporadic hematological malignancies which did develop showed decreased levels of phosphotyrosine as compared to those of wild-type P190 transgenics, although Ras was activated. These results demonstrate that the Bcr oligomerization domain contributes to the oncogenicity of Bcr/Abl in vivo.

Crkl enhances leukemogenesis in BCR/ABL P190 transgenic mice

The adapter protein Crkl has been implicated in the abnormal signal transduction pathways activated by the Bcr/Abl oncoprotein, which causes Philadelphia-positive leukemias in humans. To investigate the role of Crkl in tumorigenesis, we have generated transgenic mice that express human Crkl from the CRKL promoter. Western blot analysis showed a 4-6-fold overexpression of transgenic Crkl above endogenous crkl in two lines and increased constitutive complex formation between Crkl and C3G, an exchange factor for the small GTPase Rap1. This was associated with a significant increase in integrin-based motility of transgenic macrophages. Overexpression of Crkl was associated with increased incidence of tumor formation, and Rap1 was activated in a metastatic mammary carcinoma. The coexpression of Crkl and Bcr/Abl in mice transgenic for P190 BCR/ABL and CRKL markedly increased the rapidity of development of leukemia/lymphoma, decreasing the average survival by 3.8 months. These results provide direct evidence that Crkl plays a role in tumor development and is important in the leukemogenesis caused by Bcr/Abl.

Reduced oncogenicity of p190 Bcr/Abl F-actin-binding domain mutants

The deregulated Bcr/Abl tyrosine kinase is responsible for the development of Philadelphia (Ph)-positive leukemia in humans. To investigate the significance of the C-terminal Abl actin-binding domain within Bcr/Abl p190 in the development of leukemia/lymphoma in vivo, mutant p190 DNA constructs were used to generate transgenic mice. Eight founder and progeny mice of 5 different lines were monitored for leukemogenesis. Latency was markedly increased and occurrence decreased in the p190 del C lines as compared with nonmutated p190 BCR/ABL transgenics. Western blot analysis of involved hematologic tissues of the p190 del C transgenics with end-stage disease showed high-level expression of the transgene and tyrosine phosphorylation of Cbl and Hef1/Cas, proteins previously shown to be affected by Bcr/Abl. These results show that the actin-binding domain of Abl enhances leukemia development but does not appear to be an absolute requirement for leukemogenesis.

Application of high-power ultrasound to enhance fluid/solid particle separation processes

The separation of fine particles from gases or liquids is a topic of permanent industrial attention. The use of ultrasonic energy to assist conventional separation techniques seems to be very promising. The adequate applications of high-intensity ultrasonic fields may contribute to improve the efficiency and capacity of the separation methods presently used. The specific mechanisms to ultrasonically enhance separation processes basically depend on the medium to be treated. In gas suspensions, where very fine particles have to be removed, ultrasonic action involves agglomeration of particles in order to increase their size and, consequently, to improve collection efficiency of conventional filters. In liquid suspensions, agglomeration is, in general, less efficient than in gases. Nevertheless, the ultrasonic energy is useful to dewater fine-particle high-concentration suspensions such as slurries and sludges. This paper deals with the application of acoustic energy to assist fluid/solid separation processes in gas and liquid suspensions and presents some theoretical and experimental results in specific applications.

Congenital muscular dystrophy with rigid spine syndrome: a clinical, pathological, radiological, and genetic study

Rigid spine syndrome is a term first proposed by Dubowitz to describe a subset of patients affected by myopathy with early spinal contractures as a prominent feature. While spinal rigidity is a nonspecific feature, found in Emery-Dreifuss muscular dystrophy and in some congenital myopathies, it is also a prominent feature in a group of patients with merosin-positive congenital muscular dystrophy, where it is generally associated with stable or only slowly progressive weakness and early respiratory insufficiency. Recently, the first locus for congenital muscular dystrophy in association with rigid spine syndrome was mapped to chromosome 1p35-p36 in consanguineous Moroccan, Turkish, and Iranian families. We present here a detailed phenotypic description of the familial syndrome linked to this locus, describing 4 siblings (3 boys and 1 girl) of Northern European-American heritage who are the offspring of a nonconsanguineous marriage. All 4 siblings were affected by hypotonia and prominent neck weakness in infancy, early spinal rigidity, and early scoliosis. After initial improvement, muscle strength stabilizes or slowly declines, and skeletal deformities and respiratory insufficiency supervene. Muscle biopsy in an affected child at age 9 months revealed minimal, nonspecific myopathic changes, leading to a diagnosis of "minimal change myopathy." Muscle biopsy in his sibling, at the age of 14 years, revealed chronic and severe myopathic (dystrophic) changes, with normal staining for laminin-2 and for proteins of the dystrophin-glycoprotein complex. A possible explanation for these biopsy findings is that magnetic resonance imaging of the thighs reveals stereotyped selective muscle involvement, with the selectivity more pronounced early in the disease course followed by widespread muscular signal abnormalities in the late stages of the disease. In this family, linkage to the chromosome 1p rigid spine syndrome locus (RSMD1) is supported by maximum LOD scores for several markers of 1.81 at theta = 0, representing the maximum statistical power possible for this family. In combination with the previous report, this syndrome is linked to the RSMD1 locus with a summated maximum LOD score of 6.29, and analysis of recombination events in our family narrows the previously reported RSMD1 locus to 3 centiMorgans.

Progressive neurodegeneration in aspartylglycosaminuria mice

Aspartylglycosaminuria (AGU) is one of the most common lysosomal storage disorders in humans. A mouse model for AGU has been recently generated through targeted disruption of the glycosylasparaginase gene, and at a young age the glycosyl asparaginase-deficient mice demonstrated many pathological changes found in human AGU patients (Kaartinen V, Mononen I, Voncken J-W, Gonzalez-Gomez I, Heisterkamp N, Groffen J: A mouse model for aspartylglycosaminuria. Nat Med 1996, 2:1375-1378). Our current findings demonstrate that after the age of 10 months, the general condition of null mutant mice gradually deteriorated. They suffered from a progressive motoric impairment and impaired bladder function and died prematurely. A widespread lysosomal hypertrophy in the central nervous system was detected. This neuronal vacuolation was particularly severe in the lateral thalamic nuclei, medullary reticular nuclei, vestibular nuclei, inferior olivary complex, and deep cerebellar nuclei. The oldest animals (20 months old) displayed a clear neuronal loss and gliosis, particularly in those regions, where the most severe vacuolation was found. The severe ataxic gait of the older mice was likely due to the dramatic loss of Purkinje cells, intensive astrogliosis and vacuolation of neurons in the deep cerebellar nuclei, and the severe vacuolation of the cells in vestibular and cochlear nuclei. The impaired bladder function and subsequent hydronephrosis were secondary to involvement of the central nervous system. These findings demonstrate that the glycosylasparaginase-deficient mice share many neuropathological features with human AGU patients, providing a suitable animal model to test therapeutic strategies in the treatment of the central nervous system effects in AGU.

Increased submucosal nerve trunk caliber in aganglionosis: a "positive" and objective finding in suction biopsies and segmental resections in Hirschsprung's disease

OBJECTIVE

To establish the diagnostic usefulness of submucosal hypertrophic nerve trunk morphology in Hirschsprung's disease as a quantifiable parameter supportive of aganglionosis on hematoxylin-eosin-stained sections.

DESIGN

We retrospectively evaluated size and density of submucosal nerves on hematoxylin-eosin-stained sections and S100 protein-stained sections of resected segments from 13 patients with Hirschsprung's disease, and in sections of 20 aganglionic and 50 ganglionic rectal suction biopsies.

SETTING

All patients were seen at Childrens Hospital Los Angeles (Calif), a tertiary-care pediatric center; the age of patients at diagnosis or resection ranged between 2 days and 3 years.

RESULTS

Aganglionic segments contain many distinct nerve trunks greater than 40 microm in diameter. Ganglionic segments/biopsies showed no nerve trunk larger than this threshold value (P approximately .0000). Nerve trunks of such caliber are rarely encountered in pathologic transition zones and sites of colostomy.

CONCLUSIONS

Submucosal nerve trunks that are 40 microm or greater in diameter strongly correlate with abnormal innervation/aganglionosis. Use of this objective parameter in evaluating suction biopsies should be helpful in the morphologic diagnosis of Hirschsprung's disease in infancy and early childhood.