A mouse model for the human lysosomal disease aspartylglycosaminuria.

Aspartylglycosaminuria (AGU), the most common disorder of glycoprotein degradation in humans, is caused by mutations in the gene encoding the lysosomal enzyme glycosylasparaginase (Aga). The resulting enzyme deficiency allows aspartylglucosamine (GlcNAc-Asn) and other glycoasparagines to accumulate in tissues and body fluids, from early fetal life onward. The clinical course is characterized by normal early development, slowly progressing to severe mental and motor retardation in early adulthood. The exact pathogenesis of AGU in humans is unknown and neither therapy nor an animal model for this debilitating and ultimately fatal disease exists. Through targeted disruption of the mouse Aga gene in embryonic stem cells, we generated mice that completely lack Aga activity. At the age of 5-10 months a massive accumulation of GlcNAc-Asn was detected along with lysosomal vacuolization, axonal swelling in the gracile nucleus and impaired neuromotor coordination. A significant number of older male mice had massively swollen bladders, which was not caused by obstruction, but most likely related to the impaired function of the nervous system. These findings are consistent with the pathogenesis of AGU and provide further data explaining the impaired neurological function in AGU patients.

Quantitative analysis and modelling of hepatic iron stores using stereology and spatial statistics.

Hepatic iron overload is a common clinical problem resulting from hyperabsorption syndromes and from chronic transfusion therapy. Not only does iron loading vary between reticuloendothelial stores and hepatocytes, but iron is heterogeneously distributed within hepatocytes as well. Since the accessibility of iron particles to chelation may depend, in part, on their distribution, we sought to characterize the shape and scale of iron deposition in humans with transfusional iron overload. Toward this end, we performed a histological analysis of iron stores in liver biopsy specimens of 20 patients (1.3-57.8 mg iron/g dry tissue weight) with aid of electron and light microscopy. We estimated distributions related to variability in siderosomal size, proximity of iron centres and inter-cellular iron loading. These distributions could be well modelled by Gamma distribution functions over most of the pathologic range of iron concentrations. Thus, for a given liver iron burden, a virtual iron-overloaded liver could be created that served as a model for the true histologic appearance. Such a model may be helpful for understanding the mechanics of iron loading or in predicting response to iron removal therapy.

A non-invasive, in vivo technique for monitoring vascular status of glioblastoma during angiogenesis.

The growth of solid tumors dependent on the process of angiogenesis in which growth factors secreted by tumor and stromal cells promote endothelial cell proliferation, migration, and maturation. This process generates a tumor-specific vascular supply and enables small or dormant tumors to grow rapidly with exponential increases in tumor volume. Determination of tumor oxygenation at the microvascular level will provide important insight into tumor growth, angiogenesis, necrosis, and therapeutic response, and will facilitate to develop protocols for studying tumor behavior. A non-invasive multi-modality approach based on near infrared spectroscopy (NIRS) technique, namely: Steady State Diffuse Optical Spectroscopy (SSDOS) along with Magnetic Resonance Imaging (MRI) is applied for monitoring the concentration of oxyhemoglobin, deoxyhemoglobin and water within tumor region and for studying the vascular status of tumor and the patho-physiological changes that occur during angiogenesis. Since, the growth of solid tumors depends on the formation of new blood vessels, an association between intramural microvessel density (MVD) and tumor oxygenation is also investigated. The relative decrease in oxygenation value with tumor growth indicates that though blood vessels infiltrate and proliferate the tumor region, a hypoxic trend is clearly present.

[Heparin immune thrombocytopenia in a hemodialysis patient. A case report. Literature review]. / Trombopenia inmune inducida por heparina en hemodiálisis a propósito de un caso. Revisión de la literatura.

Heparin-induced thrombocytopenia (HIT) is an important side effect of heparin therapy associated with significant morbidity and mortality if unrecognized. The platelet count typically falls below 150,000/ll 5-14 days after heparin is started. Thrombosis is the major clinical complication. We present the case gives a patient that develops a deep vein thrombosis ilio-femoral left, with trombocytopenia, one week after beginning treatment with haemodialysis in which Ac anti heparin is detected by test PaGIA (Particle Gel Inmuno Assay.

Quantitative short echo time 1H-MR spectroscopy of untreated pediatric brain tumors: preoperative diagnosis and characterization.

PURPOSE: Our aims were to evaluate the metabolic profiles of pediatric brain tumors with short echo time (TE) MR spectroscopy and absolute quantitation of metabolite concentrations (in mmol/kg of tissue) and to describe metabolic features that distinguish individual tumor types and that may help to improve preoperative diagnosis of specific tumors. METHODS: MR imaging examinations of 60 patients with untreated brain tumors (14 medulloblastomas, 5 anaplastic astrocytomas, 3 low-grade astrocytomas, 17 pilocytic astrocytomas, 4 anaplastic ependymomas, 5 ependymomas, 3 choroid plexus papillomas, 3 choroid plexus carcinomas, and 6 pineal germinomas) were reviewed. Single-voxel proton MR spectroscopy with a TE of 35 ms was performed and absolute metabolite concentrations were determined by using fully automated quantitation. RESULTS: Taurine (Tau) was significantly elevated in medulloblastomas (P < .00001) compared with all other tumors pooled (All Other). Tau was also observed consistently, at lower concentration, in pineal germinomas. Creatine (Cr) was significantly reduced in pilocytic astrocytomas, distinguishing them from All Other (P < .000001). The MR spectra of choroid plexus papillomas exhibited low Cr (P < .01) concentrations; however, myoinositol was elevated (P < .01) and total choline (tCho) (P < .0001) was reduced relative to All Other. Choroid plexus carcinomas had low Cr (P < .01 versus All Other) and the lowest Cr/tCho ratio (P < .0001 versus All Other) among all tumors studied. Guanidinoacetate was reduced in low-grade astrocytomas and anaplastic astrocytomas (P < .00001) versus All Other, whereas ependymoma and anaplastic ependymomas exhibited particularly low N-acetylaspartate (P < .00001 versus All Other). CONCLUSION: Quantitative proton MR spectroscopy reveals features of pediatric brain tumors that are likely to improve preoperative diagnoses.

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.

Primary recurrent leiomyosarcoma of the breast. Case report with ultrastructural and immunohistochemical study and review of the literature.

The authors report a case of recurrent mammary leiomyosarcoma in a 50-year-old woman. The neoplasia, with a recognized clinical evolution of 11 years, was resected on two occasions and had not metastasized. Microscopic examination showed 4 mitoses/10 high-power fields, moderate cytologic atypia, and, ultrastructurally, abundant myofibrils with condensations. Immunoperoxidase stains had positive results for muscle-specific antigen and showed focal reactivity for epithelial membrane antigen and S-100 protein. Analysis of the ten cases (including the present one) reveals that this neoplasm has appeared with greater frequency in women with an average age of 52 years. All neoplasms have been limited to the breast at the time of diagnosis. As a group, they have better prognosis than other sarcomas of the breast, although the possibilities of recurrence or dissemination exist, even many years after the primary extirpation. The size of the tumor and mitotic activity seem to be of little prognostic value. Mammary leiomyosarcoma shares clinical and pathologic similarities with subcutaneous leiomyosarcoma in other anatomic sites.

Dyke Award. The search for human telencephalic ventriculofugal arteries.

Our study traced the vascular development of the fetal telencephalon in the last two trimesters of gestation and the first 15 years of life in 60 fetal and childhood brains. We filled the macro- and microvascular beds with Microfil and made stereoscopic observations of cleared 0.5- to 1.0-cm-thick sections. Separately, we identified developing vascular structures histologically. In our youngest specimen (16-weeks gestation), transcerebral channels with walls consisting of a single layer of endothelium and varying in diameter from 10 to 50 microns originated from leptomeningeal arteries and veins at right angles to the surface and passed through the cortical plate (future cortex). They branched at varying depths within the mantle and germinal matrix surrounding the lateral ventricles. At deeper levels the channels freely anastomosed with each other. A cortical microvascular network did not appear until 22 to 24 weeks. The new endothelial channels were derived from leptomeningeal vessels and from larger transcerebral channels. Most regions of isocortex developed a microvascular plexus simultaneously, regardless of degree of maturation. Striatal channels matured earlier than extrastriatal channels, having developed a muscularis to within 100 microns of the ganglionic eminence by 22- to 24-weeks gestation. Maturation of the vascular walls of extrastriatal channels into proper arteries and veins occurred during the first postnatal year. Anastomotic channels were present throughout the leptomeningeal, striatal, and extrastriatal regions in all of our specimens from 16 weeks gestation to 15 years old. Our study does not support the existence of ventriculofugal arteries and deep white matter arterial border zones in the human fetus and neonate, which have been postulated to be the basis of "periventricular" leukomalacia.

Brain tumor development in rats is associated with changes in central nervous system cytokine and neuropeptide systems.

Cytokines have roles in tumor biology and induce neurological manifestations. Cytokines produced in response to a brain tumor may generate neurological manifestations via paracrine action. We investigated cytokine modulation in an in vivo brain tumor model with behavioral, morphological, and molecular approaches. Rat C6 glioma cells were implanted into the third cerebral ventricle of Wistar rats, their behavior was monitored, and the development of an intracranial tumor of astrocytic origin was confirmed by histology and positive immunostaining for vimentin, S-100 protein, and glial fibrillary acidic protein. Sensitive and specific RNase protection assays were used to analyze cytokine messenger RNA (mRNA) in brain regions from anorexic brain tumor-bearing animals. Brain tumor formation was associated with significant increased levels of interleukin (IL)-1beta, IL-1 receptor antagonist, IL-1 receptor type I, tumor necrosis factor (TNF)-alpha, and transforming growth factor (TGF)-beta1 mRNAs in the cerebellum, hippocampus, and hypothalamus. IL-1 receptor accessory proteins I and II mRNAs were increased in the cerebellum and hypothalamus. We also examined hypothalamic feeding-associated components: neuropeptide Y and proopiomelanocortin mRNAs were down-regulated, glycoprotein 130 mRNA levels were up-regulated, and leptin receptor (OB-R) mRNA levels were unchanged. These dissimilar profiles of mRNA expression suggest specificity of brain tumor-induced transcriptional changes. The data implicate cytokines as important factors in brain tumor-host interactions in vivo. The data also show that the C6 cell-induced glioma can be used as a behavioral-molecular model to study cytokine and neuropeptide modulation and action during the host biochemical and physiological responses to brain tumor development. Paracrine interactions seem pivotal because cytokine modulation was observed in various brain regions. These results also suggest that cytokine and neuropeptide changes during brain tumor progression are involved in brain tumor-associated neurological and neuropsychiatrical manifestations.

Autoregulation of the interleukin-1 system and cytokine-cytokine interactions in primary human astrocytoma cells.

Cytokines are proposed to play important roles in brain tumor biology. Previous studies reported on interleukin-1beta (IL-1beta) production and IL-1 receptor type I (IL-1RI, signaling receptor) expression in human astrocytomas, and on IL-1beta action in astrocytoma cell lines. However, all studies that have tested the direct action of cytokines have used exclusively astrocytoma cell lines, which do not recapitulate the in situ astrocytoma. Here, we demonstrate that astrocytoma cells obtained shortly after tumor neurosurgical resection respond to the direct application of human IL-1beta with a significant upregulation of IL-1alpha, IL-1beta, IL-1RI, and tumor necrosis factor-alpha (TNF-alpha) mRNAs. IL-1 receptor antagonist (IL-1Ra, an endogenous inhibitor that blocks IL-1alpha and IL-1beta actions) mRNA was not upregulated. Application of heat-inactivated IL-1beta had no effect on any cytokine component examined, demonstrating specificity of action. On the other hand, IL-1beta application did not modulate any cytokine component in acutely resected and dissociated primitive neuroectodermal tumor cells. The data have implications for a positive autoregulatory IL-1beta feedback system and synergistic IL-1beta <=> TNF-alpha interactions, which can be involved in the growth of pilocytic astrocytomas. The results together with our previous studies also support the notion that IL-1Ra or a compound with similar cytokine inhibitory activity could be useful for brain immunotherapy of astrocytomas.

Diffuse arteriovenous malformations: a clinical, radiological, and pathological description.

In a review of our series of patients with arteriovenous malformations (AVMs), a group with atypical angiographic and histopathological characteristics was discovered. Unlike the typical AVM, these lesions contained normal cerebral tissue between the abnormal vessels. We call these lesions diffuse AVMs, and think that this AVM represents one end of the AVM spectrum from a tight nidus to a diffuse lesion. The mean age of these patients was 18.1 years. Eight patients presented with an intracerebral hemorrhage, two with seizures, one with headache without hemorrhage, and one with ischemic symptoms compatible with vascular steal. Cerebral angiography revealed three AVMs to be 2 to 4 cm in diameter, four were 4 to 6 cm in diameter, and five were > 6 cm in diameter. Characteristic angiographic features included multiple small arterial feeders, small ectatic vessels in the malformation itself, multiple small draining veins, and a diffuse, puddling appearance of the contrast dye. Despite 16 operations in 11 patients, complete resection of the AVM was accomplished in only 8. The four patients with residual disease have received radiation therapy. Histopathology of the surgical specimens found AVM vessels interspersed among normal appearing neurons and white matter. Leptomeningeal angiodysplasia was noted when the cerebral cortex was involved. Gliosis was noted in some cases. Diffuse AVMs represent a difficult surgical challenge and recognition of the lesion aids in surgical planning.

Pediatric intracranial hemangioendotheliomas: case report.

OBJECTIVE AND IMPORTANCE: Intracranial hemangioendotheliomas are rare lesions, especially in the pediatric age group. Recognizing hemangioendotheliomas as a differential in intracranial tumors of vascular origin is important; complete excision results in a cure, and medical therapy for those lesions that are not resectable produces long-term survival. CLINICAL PRESENTATION: We report two patients, a 7-year-old female patient with a lesion in the right gasserian ganglion and a 3-month-old male patient with a cervicomedullary junction tumor. INTERVENTION: The 7-year-old underwent a gross total removal with no recurrence. The 3-month-old underwent a partial resection followed by treatment with interferon alpha-2a, with a decrease in the size of the residual tumor. Both patients have been followed for more than 4 years without a recurrence or progression of the tumor. CONCLUSION: Hemangioendotheliomas are fairly indolent tumors and may be treated with complete surgical resection, resulting in a cure. In cases in which complete tumor removal is not possible, adjunctive therapy with interferon alpha-2a may control residual tumor growth.

Isolated lumbosacral neurenteric cyst with partial sacral agenesis: case report.

A case of an isolated intraspinal lumbosacral neurenteric cyst in a 5-year-old girl with partial sacral agenesis is reported. The cyst wall contained transitional epithelium and smooth muscle characteristic of the urinary bladder, suggesting a possible cloacal origin of the cyst. No prior cases of concomitant neurenteric cysts with partial or complete sacral agenesis have been reported, and the occurrence of an isolated intradural extramedullary sacral neurenteric cyst is rare. The possible pathogenesis of this lesion is described.

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.

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.

Investigation of the influence of humidity on the ultrasonic agglomeration of submicron particles in diesel exhausts.

Removing very fine particles in the 0.01-1 micro m range generated in diesel combustion is important for air pollution abatement because of the impact such particles have on the environment. By forming larger particles, acoustic agglomeration of submicron particles is presented as a promising process for enhancing the efficiency of the current filtration systems for particle removal. Nevertheless, some authors have pointed out that acoustic agglomeration is much more efficient for larger particles than for smaller particles. This paper studies the effect of humidity on the acoustic agglomeration of diesel exhausts particles in the nanometer size range at 21 kHz. For the agglomeration tests, the experimental facility basically consists of a pilot scale plant with a diesel engine, an ultrasonic agglomeration chamber a dilution system, a nozzle atomizer, and an aerosol sampling and measuring station. The effect of the ultrasonic treatment, generated by a linear array of four high-power stepped-plate transducers on fumes at flow rates of 900 Nm(3)/h, was a small reduction in the number concentration of particles at the outlet of the chamber. However, the presence of humidity raised the agglomeration rate by decreasing the number particle concentration by up to 56%. A numerical study of the agglomeration process as a linear combination of the orthokinetic and hydrodynamic agglomeration coefficients resulting from mutual radiation pressure also found that acoustic agglomeration was enhanced by humidity. Both results confirm the benefit of using high-power ultrasound together with humidity to enhance the agglomeration of particles much smaller than 1 micro m.

Recurrence patterns and anaplastic change in a long-term study of pilocytic astrocytomas.

Thirty-six cases of pilocytic astrocytomas treated at the Childrens Hospital of Los Angeles from 1984 through 1995 were reviewed. The mean age at initial presentation was 8 years (range 15 months to 14 years). These patients were followed for an average of 5.5 years. No patient was given chemotherapy or radiation therapy after the initial surgery for pilocytic astrocytoma. Twenty-three patients (64%) had a gross total resection with no residual tumor on immediate postoperative imaging studies. Three of these children had tumor recurrences 2-5 years after their initial surgery, requiring re-excision of their tumors. All 3 patients are subsequently tumor-free, with follow-up ranging from 4 to 10 years. In 4 patients with residual tumor involving the brainstem, there has been neither imaging evidence of tumor enlargement nor progression of clinical findings at 2.5, 4, 6 and 6 years, respectively. Nine of the 13 patients with residual tumor underwent re-excision, either for progression of symptoms or documented tumor growth on imaging studies. The second operation was undertaken an average of 1 year (range 1 month to 6 years) after the first. In 4 of these children (11% of our whole series), the recurrent tumor was classified as anaplastic astrocytoma. Three of these 4 children received radiation and/or chemotherapy, with only 1 patient showing disease progression in the follow-up period. Repeat blinded histopathological examination of these tumors confirmed both diagnoses. However, it was noted that 3 of the 4 pilocytic astrocytomas which subsequently showed anaplastic change initially displayed increased perivascular cellularity, while only 2 of the remaining 32 tumors exhibited this feature. These results encourage continued vigilance in the follow-up of pilocytic astrocytomas, and describe a histological feature which might indicate a more aggressive disease course.

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.

Subcutaneous palisading granuloma of the scalp in childhood.

Subcutaneous palisading granulomas, lesions characterized by collagen necrosis and chronic inflammatory changes, may present as ill-defined, immobile, nontender masses of the scalp. They are frequently multiple and may vary in size over time. Imaging studies rarely show involvement of the calvarium. The histological pattern of palisading histiocytes around necrobiotic granulomas is seen in association with a variety of systemic illnesses but more commonly occurs as an isolated entity in childhood. They are unlikely to herald rheumatological disease unless the erythrocyte sedimentation rate is elevated. In the presence of juvenile rheumatoid arthritis, histological confirmation is usually not indicated. If the lesions are not associated with any other clinical symptoms excisional biopsy may be indicated to establish a diagnosis. The nodules need not be removed as they will spontaneously regress.