Pathological and molecular progression of astrocytomas in a GFAP:12 V-Ha-Ras mouse astrocytoma model

We previously characterized a genetically engineered mouse astrocytoma model with embryonic astrocyte-specific, activated ¹²V-Ha-RAS (GFAP-RAS) transgenesis. The GFAP-RAS line Ras-B8 appears normal at birth, but 50% of mice die by 4 months from low- and high-grade astrocytomas. We examined the development and progression of astrocytomas in the Ras-B8 genetically engineered mouse. At embryonic day 16.5 (E16.5), there were no pathological differences compared to control littermates, aside from transgene expression. Diffuse astroglial hyperplasia was the first distinguishing feature in the 1-week-old Ras-B8 mice; however, these astrocytes were not transformed in vitro or in vivo. From 3 to 8 weeks the incidence of low-grade astrocytomas progressively increased with 85% of 12-week-old mice harboring low- or high-grade astrocytomas, the latter characterized by increased proliferation, nuclear atypia, and angiogenesis. Tp53 mutations were detected in both astrocytoma grades, with high-grade astrocytomas expressing elevated levels of epidermal growth factor receptor and vascular endothelial growth factor, plus decreased levels of PTEN and p16, similar to human astrocytomas. We postulate that expression of ¹²V-Ha-RAS in astroglial precursors induces astroglial hyperplasia, but transformation and subsequent progression requires additional molecular alterations resulting from aberrant activated p21-RAS. Of interest, many of these acquired alterations occur in human astrocytomas, further validating GFAP-RAS as a useful model for studying astrocytoma development and progression.     

Detection of antibodies specific to an antigenic cell wall galactomannoprotein for serodiagnosis of Aspergillus fumigatus aspergillosis

Aspergilloma and invasive aspergillosis are important opportunistic infections caused by Aspergillus species, among which Aspergillus fumigatus is the most common species associated with human disease. We developed an enzyme-linked immunosorbent assay (ELISA)-based antibody assay with Afmp1p, a purified recombinant antigenic cell wall galactomannoprotein of A. fumigatus. Evaluation of the test with guinea pig sera against A. fumigatus and other pathogenic fungi indicated that this assay was specific for A. fumigatus. Clinical evaluation revealed that the assay was 100% sensitive for patients with aspergilloma and 33.3% sensitive for patients with invasive aspergillosis. No false-positive results were found for serum samples from 80 healthy blood donors, 6 patients with typhoid fever, 4 patients with melioidosis, 20 patients with penicilliosis marneffei, 5 patients with candidiasis, and 4 patients with cryptococcosis, indicating a high specificity of the test. Thus, this ELISA-based test for the detection of anti-Afmp1p antibody can be of significant value as a diagnostic for aspergillosis.     

A chronic mouse model of Parkinson's disease has a reduced gait pattern certainty

The purpose of this investigation was to determine if a chronic Parkinson's disease mouse model will display less certainty in its gait pattern due to basal ganglia dysfunction. A chronic Parkinson's disease mouse model was induced by injecting male C57/BL mice with 10 doses of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (25 mg/kg) (MPTP) and probenecid (250 mg/kg) (P) over 5 weeks. This chronic model produces a severe and persistent loss of nigrostriatal neurons resulting in dopamine depletion and locomotor impairment. The control mice were treated with probenecid alone. Fifteen weeks after the last MPTP/P treatment, the mice were videotaped in the sagittal plane with a digital camera (60 Hz) as they ran on a motorized treadmill at a speed of 10 m/min. The indices of gait and gait variability were calculated. Stride length was significantly (p = 0.016) more variable in the chronic MPTP/P mice. Additionally, the chronic MPTP/P mice had a statistically less certain gait pattern when compared to the control mice (p = 0.02). These results suggest that variability in the gait pattern can be used to evaluate changes in neural function. Additionally, our results imply that disorder of the basal ganglia results in less certainty in modulating the descending motor command that controls the gait pattern.     

Biological Activity of a Partially Purified Inhibitor of Vaccinia Virus Hemagglutinin

An inhibitor acting against vaccinia virus hemagglutinin, and producing a hemagglutinin-negative virus, was separated from tumorous ascitic plasma. The finding that the partially purified inhibitor was biologically active strengthens the evidence for a specific role of the inhibitor in altering the virus.     

Model analysis of the contribution of atrial contraction to ventricular filling

We studied the contribution of atrial contraction to ventricular filling by modelling the right heart and the associated vasculature. Right atrial and ventricular contractions were represented by periodically varying volume elastances which are independent of loading conditions. The values of these elastances were experimentally determined. The systemic veins, the tricuspid valve and the pulmonary arteries were all represented by impedance networks. For these impedances we used as much experimentally obtained information as possible. The dynamic pressure and flow waveforms observed in the model under control conditions generally agreed with those reported in the literature. We therefore proceeded to analyze the effects of changing the time interval between atrial systole and ventricular systole, atrial contractility, heart rate, and blood inertance. There was an optimal atrial systole-ventricular systole interval of about 0.1 sec for ventricular filling. Stroke volume of the ventricle was enhanced by an increase in atrial contractility, a decrease in heart rate, and an increase in blood inertance. The effect of changing atrial compliance was found to be dependent on heart rate. Contribution of atrial contraction to ventricular filling was also found to be more significant during exercise than at rest.     

Evaluation of a Selective Transport Medium for Gastric Biopsy Specimens To Be Cultured for Helicobacter pylori

Since the means of culturing Helicobacter pylori may not be available in some laboratories, prolonging the survival of this organism during transportation is a major concern in terms of improving detection rates. A selective transport medium was evaluated for the preservation of H. pylori from 254 gastric biopsy specimens collected from a rural area in China where culturing is not feasible. Gastric biopsy specimens were inoculated in sterile broth consisting of brain heart infusion (BHI) broth, horse serum, and yeast extract supplemented with vancomycin, amphotericin B, and nalidixic acid (VAN). Of the 254 biopsy specimens, 238 were identified by histology to have H. pylori infection. Total rates of recovery of H. pylori from the H. pylori-positive gastric biopsy specimens stored in the BHI-VAN broth ranged from 76 to 46% after storage of specimens for 5 to 9 days. In conclusion, the selective medium is useful for prolonging the survival of H. pylori in gastric biopsy specimens for which immediate culture is not feasible.     

Sexual transmission of hepatitis B infection despite the presence of hepatitis B virus immunity in recipients of allogeneic bone marrow transplantation.

BACKGROUND: After hematopoietic cell transplantation (HCT), hepatitis due to hepatitis B virus (HBV) rarely occurred beyond the initial 12 months after transplantation. OBJECTIVES: We investigated the cause of "late" hepatitis due to HBV infection in two recipients after allogeneic HCT. STUDY DESIGN: Two male patients with acute myeloid leukemia and light chain myeloma, respectively, developed HBV-related hepatitis more than 2 years after HCT. All serum samples collected from the recipients, donors and their respective spouses were tested for HBV DNA by nested PCR, and if positive further quantified by Digene Hybrid Capture assay II. The HBV genotype was determined by PCR and sequencing. RESULTS: Genotypic analysis suggested that the cause of "late" hepatitis was due to acute HBV infection transmitted from their respective spouse. CONCLUSION: Our findings suggested that sexual precautions should be taken in these patients after HCT. Alternatively, or even additionally, active vaccination should be delivered to these patients once they have lost their HBV immunity.     

Wound dressing with sustained anti-microbial capability

Amphiphilic poly(ether ester amide) (PEEA) multiblock copolymers were synthesized by polycondensation in the melt from hydrophilic poly(ethylene glycol) (PEG), 1,4-dihydroxybutane and short bisester-bisamide blocks. These amide blocks were prepared by reaction of 1,4-diaminobutane with dimethyl adipate in the melt. A range of multiblock copolymers were prepared, with PEG contents varying from 23-66 wt %. The intrinsic viscosity of the PEEA polymers varied from 0.58-0.78. Differential scanning calorimetry showed melting transitions for the PEG blocks and for the amide-ester blocks, suggesting a phase separated structure. Both the melting temperature and the crystallinity of the hard amide-ester segments decreased with increasing PEG content of the polymers. The equilibrium swelling ratio in phosphate buffered saline (PBS) increased with increasing amount of PEG in the polymers and varied from 1.7 to 3.7, whereas the polymer that contained 66 wt % PEG was soluble in PBS. During incubation of PEEA films in PBS, weight loss and a continuous decrease in the resulting inherent polymer viscosity was observed. The rate of degradation increased with increasing PEG content. The composition of the remaining matrices did not change during degradation. A preliminary investigation of the protein release characteristics of these PEEA copolymers showed that release of the model protein lysozyme was proportional to the square root of time. The release rate was found to increase with increasing degree of swelling of the polymers.     

Epstein-Barr-virus-transformed lymphoblastoid cell lines derived from patients with X-linked agammaglobulinaemia and Wiskott-Aldrich syndrome: responses to B cell growth and differentiation factors.

Epstein-Barr-virus-transformed B lymphoblastoid cell lines (EBV-transformed LCL) from three patients with X-linked agammaglobulinaemia (XLA), six patients with Wiskott-Aldrich Syndrome (WAS), and seven normal donors, were tested for growth and differentiation in response to human recombinant IL-4, a commercially available, low molecular weight B cell growth factor (BCGFlow), and B cell differentiation factor (BCDF) secreted by the T24 cell line, now known to be IL-6. Proliferation (3H-TdR uptake) by EBV-transformed LCL from both XLA and WAS patients in response to BCGFlow was similar to that obtained with the normal cell lines. In addition, three normal and three WAS, but none of the XLA EBV-transformed LCL, proliferated a little in response to IL-4. All the normal B cell lines secreted IgM, and six out of the seven secreted IgG in response to BCGFlow and BCDF. A similar pattern of response was obtained with the WAS EBV-transformed LCL (6/6 secreted IgM and 4/6 secreted IgG). Several of the normal and WAS EBV-transformed LCL also secreted IgM and IgG in response to IL-4. In contrast, the lines from the XLA patients were abnormal. One secreted large amounts of IgM and two secreted small amounts, but none of the XLA lines secreted IgG constitutively or in response to any of the factors (IL-4, BCDF). The lack of detectable IgG secretion by the XLA lines was probably due to an absence of precommitted IgG B cell precursors transformed by EBV rather than an intrinsic inability to respond to BCGF and BCDF. All of the lines, including those derived from XLA patients, were shown to secrete B cell growth and differentiation factors detected on indicator B cell lines. These results suggest that the abnormal X-linked genes responsible for XLA and WAS do not interfere with B cell responses to B cell growth and differentiation factors.     

TGF-β1 Null Mutation Leads to CD154 Upregulated Expression in Affected Tissues

The TGF-1(–/–) mouse is a murine model for systemic autoimmune disease. The aim of this study is to elucidate the immunological mechanism that leads to multifocal tissue inflammation and autoantibody production in TGF-1(–/–) mice. Heart, lung, liver, and salivary gland from TGF-1(–/–) were assessed for CD154 expression by RT-PCR and immunohistochemistry. Compared to wild-type littermates, CD154 expression was elevated in all tissues studied. Furthermore, IL-12 mRNA was expressed in the salivary gland and heart of TGF-1(–/–) mice and not in wild-type littermates. This suggests that the CD154 pathway is activated in these tissues. This shows that TGF-1 regulates CD154 expression leading to spontaneous IL-12 production and autoimmunity.