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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

[The professional profile of nurses in special units]. / Estudio sobre el perfil profesional de las enfermeras/os en unidades especiales.

A study was made of the professional profile of nurses working in the intensive care or coronary units of the hospitals of the Community of Castilla-La Mancha, Spain. The study was based on a questionnaire completed by a significant sample of nurses working in these units. It synthesizes the most relevant concerns, expectations, and opinions of these nursing professionals on the basis of the results of the authors' analysis. Although most of the nursing professionals were satisfied with the care that they provide, there is demand for further training of nurses working in intensive care and coronary units. Ideas and questions about the future of nursing professionals in special intensive care and emergency units are discussed. The development of professional certification for special care is considered, which undoubtedly would contribute to meeting the demands of these professionals.

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.

Interleukin-1 alpha (IL-1 alpha), IL-1 beta, IL-1 receptor type I, IL-1 receptor antagonist, and TGF-beta 1 mRNAs in pediatric astrocytomas, ependymomas, and primitive neuroectodermal tumors.

Interleukin-1 alpha (IL-1 alpha), IL-1 beta, interleukin-1 receptor type I (IL-1RI, signaling receptor), and IL-1 receptor antagonist (IL-1Ra, endogenous inhibitor) are pivotal components of the IL-1 system. IL-1 and other cytokines induced by IL-1, such as TGF-beta 1, may participate in the growth of various tumor cells. In children, primary nervous system tumors represent the most common solid malignancy. We investigated the levels of IL-1 alpha, IL-1 beta, IL-1RI, IL-1Ra, and TGF-beta 1 mRNAs in pediatric astrocytomas (n = 19), ependymomas (n = 13), and primitive neuroectodermal tumors (n = 22) using sensitive and specific RNase protection assays. The data show a significant distinct cytokine mRNA profile among brain tumor types. Pilocytic, nonpilocytic, and anaplastic astrocytomas have significant increased levels of IL-1 beta, IL-1RI, and TGF-beta 1 mRNAs, but low levels of IL-1Ra mRNA; this may have implications for an IL-1 beta feedback system and IL-1 beta<-->TGF-beta 1 interactions in astrocytomas. Ependymomas show increased levels of IL-1 alpha and IL-1 beta mRNAs associated with low levels of IL-1Ra mRNA; primitive neuroectodermal tumors do not exhibit increased levels of any cytokine component examined. The data also suggest that a dysregulation of the balance between stimulatory and inhibitory cytokines may be involved in the growth and development of brain tumors via autocrine/paracrine mechanisms.