Ventricular dilation and elevated aqueductal pulsations in a new experimental model of communicating hydrocephalus

In communicating hydrocephalus (CH), explanations for the symptoms and clear-cut effective treatments remain elusive. Pulsatile flow through the cerebral aqueduct is often significantly elevated, but a clear link between abnormal pulsations and ventriculomegaly has yet to be identified. We sought to demonstrate measurement of pulsatile aqueductal flow of CSF in the rat, and to characterize the temporal changes in CSF pulsations in a new model of CH. Hydrocephalus was induced by injection of kaolin into the basal cisterns of adult rats (n = 18). Ventricular volume and aqueductal pulsations were measured on a 9.4 T MRI over a one month period. Half of the animals developed ventricular dilation, with increased ventricular volume and pulsations as early as one day post-induction, and marked chronic elevations compared to intact controls (volume: 130.15 +/- 83.21 microl vs. 15.52 +/- 2.00 microl; pulsations: 114.51 nl +/- 106.29 vs. 0.72 +/- 0.13 nl). Similar to the clinical presentation, the relationship between ventricular size and pulsations was quite variable. However, the pulsation time-course revealed two distinct sub-types of hydrocephalic animals: those with markedly elevated pulsations which persisted over time, and those with mildly elevated pulsations which returned to near normal levels after one week. These groups were associated with severe and mild ventriculomegaly respectively. Thus, aqueductal flow can be measured in the rat using high-field MRI and basal cistern-induced CH is associated with an immediate change in CSF pulsatility. At the same time, our results highlight the complex nature of aqueductal pulsation and its relationship to ventricular dilation.

Substance P release and neurokinin 1 receptor activation in the rat spinal cord increase with the firing frequency of C-fibers

Both the firing frequency of primary afferents and neurokinin 1 receptor (NK1R) internalization in dorsal horn neurons increase with the intensity of noxious stimulus. Accordingly, we studied how the pattern of firing of primary afferent influences NK1R internalization. In rat spinal cord slices, electrical stimulation of the dorsal root evoked NK1R internalization in lamina I neurons by inducing substance P release from primary afferents. The stimulation frequency had pronounced effects on NK1R internalization, which increased up to 100 Hz and then diminished abruptly at 200 Hz. Peptidase inhibitors increased NK1R internalization at frequencies below 30 Hz, indicating that peptidases limit the access of substance P to the receptor at moderate firing rates. NK1R internalization increased with number of pulses at all frequencies, but maximal internalization was substantially lower at 1-10 Hz than at 30 Hz. Pulses organized into bursts produced the same NK1R internalization as sustained 30 Hz stimulation. To determine whether substance P release induced at high stimulation frequencies was from C-fibers, we recorded compound action potentials in the sciatic nerve of anesthetized rats. We observed substantial NK1R internalization when stimulating at intensities evoking a C-elevation, but not at intensities evoking only an Adelta-elevation. Each pulse in trains at frequencies up to 100 Hz evoked a C-elevation, demonstrating that C-fibers can follow these high frequencies. C-elevation amplitudes declined progressively with increasing stimulation frequency, which was likely caused by a combination of factors including temporal dispersion. In conclusion, the instantaneous firing frequency in C-fibers determines the amount of substance P released by noxious stimuli.

Neovascularization in an arterio-venous loop-containing tissue engineering chamber: role of NADPH oxidase

Using an in vivo arterio-venous loop-containing tissue-engineering chamber, we have created a variety of vascularized tissue blocks, including functional myocardium. The viability of the transplanted cells is limited by the rate of neovascularization in the chamber. A Nox2-containing nicotinamide adenine dinucleotide phosphate (NADPH) oxidase is thought to have a critical role in ischaemic angiogenesis. In this study we investigated whether NADPH oxidase is involved in the neovascularization process in the tissue-engineering chamber. New blood vessels originating from the venous and the arterial ends of the loop could be identified after 3 days, and the vessel density (by lectin staining) peaked after 7 days and was maintained for at least 14 days. This was accompanied by granulation tissue formation and concomitant increase in the mRNA level of Nox4 NADPH oxidase. Although the total level of Nox2 mRNA in the chamber tissue decreased from day 3 to day 7, immunohistochemistry identified a strong expression of Nox2 in the endothelial cells of the new vessels. In human microvascular endothelial cells, the NADPH oxidase inhibitor apocynin reduced NADPH oxidase activity and inhibited the angiogenic responses in vitro. Local treatment with the NADPH oxidase inhibitors apocynin or gp91ds-tat peptide significantly suppressed the vessel growth in the chamber. In conclusion, NADPH oxidase-dependent redox signalling is important for neovascularization in this novel tissue-engineering chamber in vivo, and boosting this signalling might be a new approach to extending vascularization and tissue growth.

Recombinant Human Erythropoietin Protects against Experimental Spinal Cord Trauma Injury by Regulating Expression of the Proteins MKP-1 and p-ERK

The present study explored the tissue-protective effect of erythropoietin in rats after experimental spinal cord injury (SCI) produced by dropping a weight onto surgically exposed spinal cord. Sixty rats were randomized to sham operation (spinal cord exposure; control), SCI plus intraperitoneal saline injection, or SCI plus intraperitoneal erythropoietin injection. Locomotor function was evaluated with Basso, Beattie and Bresnahan scores 1 day (24 h) and 7 days later, and rats were then killed for analysis of lesion site tissue. Compared with saline-treated SCI rats, erythropoietin-treated SCI rats showed significantly less locomotor dysfunction and faster locomotor recovery. Immunohistochemistry showed that erythropoietin-treated SCI rats had a significantly lower phospho-extracellular signal-regulated kinase (p-ERK) protein expression and a significantly higher mitogen-activated protein kinase phosphatase-1 (MKP-1) protein expression than saline-treated SCI rats. Haematoxylin–eosin staining showed progressive disruption of dorsal white matter and neuron loss after SCI; lesions were less severe and there was more neuron regeneration in the erythropoietin group than in the saline group. It is concluded that erythropoietin reduces pathological changes and SCI severity via down-regulation of p-ERK and up-regulation of MKP-1.

Imaging the effects of propofol on human cerebral glucose metabolism using positron emission tomography

The effects of propofol on glucose metabolism in different cerebral regions were observed, using positron emission tomography (PET) technology, to determine a possible cerebral target region. Seven healthy volunteers were injected with (18)F-fluorodeoxyglucose developing agent for PET scanning whilst awake (control group T1), during sedation (induced by 1.5 microg/ml propofol administered by target controlled injection [TCI], group T2) and when unconsciousness (induced by 2.5 microg/ml propofol administered by TCI, group T3). Whole brain glucose metabolism was reduced during propofol anaesthesia; this was initially observed in the cortical areas at the lower dose of propofol (group T2) but extended to the subcortical regions, especially the thalamus and hippocampus, at the higher dose (group T3). This suggests that these regions of the brain might be important targets that are susceptible to propofol.

Monte Carlo electron-trajectory simulations in bright-field and dark-field STEM: implications for tomography of thick biological sections

A Monte Carlo electron-trajectory calculation has been implemented to assess the optimal detector configuration for scanning transmission electron microscopy (STEM) tomography of thick biological sections. By modeling specimens containing 2 and 3 at% osmium in a carbon matrix, it was found that for 1-microm-thick samples the bright-field (BF) and annular dark-field (ADF) signals give similar contrast and signal-to-noise ratio provided the ADF inner angle and BF outer angle are chosen optimally. Spatial resolution in STEM imaging of thick sections is compromised by multiple elastic scattering which results in a spread of scattering angles and thus a spread in lateral distances of the electrons leaving the bottom surface. However, the simulations reveal that a large fraction of these multiply scattered electrons are excluded from the BF detector, which results in higher spatial resolution in BF than in high-angle ADF images for objects situated towards the bottom of the sample. The calculations imply that STEM electron tomography of thick sections should be performed using a BF rather than an ADF detector. This advantage was verified by recording simultaneous BF and high-angle ADF STEM tomographic tilt series from a stained 600-nm-thick section of C. elegans. It was found that loss of spatial resolution occurred markedly at the bottom surface of the specimen in the ADF STEM but significantly less in the BF STEM tomographic reconstruction. Our results indicate that it might be feasible to use BF STEM tomography to determine the 3D structure of whole eukaryotic microorganisms prepared by freeze-substitution, embedding, and sectioning.

HoxC6 regulation of early mammary epithelial growth and differentiation: implications for breast cancer potential

Abstract #2010

Background: Early menarche and breast development are increasingly common risk factors for breast cancer. Epigenetic mechanisms implicated include natural and anthropogenic steroids, such as estrogens, that disrupt endocrine signaling and dysregulate stem cell homeostasis. Animal models show that, although a proliferative response to estrogens in mammary epithelium is not observed until near puberty, in utero or neonatal exposure can recapitulate aberrant breast development. The molecular basis for the delay in proliferative response remains poorly understood and assessments of agent activity, potency and risk remain inaccurate. Here, we provide a candidate molecular mechanism involving the homeobox transcription factor HoxC6, through which more accurate assessments may be facilitated.
 Materials & Methods: Genetically and hormonally manipulated in vivo mouse models (HoxC6 targeted disruption, C6KO; and mammary epithelial-specific inducible HoxC6, MMTV-rtTA TRE-HoxC6-IRES-EGFP) and in vitro human breast cancer cell lines (MCF10A, MCF7 and MDA-MB-231; "231") were used to assess impacts on mammary epithelial growth, differentiation and expression of HoxC6 and its direct target genes IGFBP3, CD44 and FGFR2. Cell lines were manipulated using HoxC6 shRNA and cDNA lentivirus and activated Akt isoform retroviral expression vectors. Gene expression and signaling were measured by quantitative RT-qPCR, IHC, Western blot and using the BioPlex200 Multiplex System.
 Results: RT-qPCR analysis shows HoxC6 expression elevated in well-differentiated cell lines (MCF10A, 5.06X; MCF7, 5.16X) and decreased in more aggressive tumor cell lines (-1.95X, 231 cells; relative to A549 cells). HoxC6 knockdown in MCF10A cells results in an inhibition of cellular growth and decreased branching in 3D cultures and dysregulation of HoxC6 target genes. These results are consistent with in vivo results in which C6KO causes defective postnatal mammary epithelial growth/branching. Rescue of growth defects in knockdown MCF10A cells is achieved to varying extents with myristoylated Akt isoforms, however morphological defects persist and are associated with EMT. HoxC6 induction in stem cells is associated with altered self-renewal and differentiation. HoxC6 repression by estrogens was assessed in vivo under conditions of neonatal estrogen exposure and estrogen-free diets, showing alterations in HoxC6 and target gene expressions and other phenotypic changes.
 Discussion: Based on our results, we will present a model in which HoxC6 is estrogen-responsive and coordinates mammary stem/progenitor cell homeostatic pathways, including FGF and GH-IGF1 signaling in the control of pool size and branching morphogenesis.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 2010.

Streptococcus cristatus attenuates Fusobacterium nucleatum-induced interleukin-8 expression in oral epithelial cells

BACKGROUND AND OBJECTIVE

Oral epithelial cells may be invaded by a polymicrobial intracellular flora, including pathogens together with commensals. Various oral pathogens can induce the production of interleukin-8, a potent neutrophil chemotractant, in oral epithelial cells. Evidence from the gut suggests that commensal species may modulate inflammatory responses to pathogens. The aim of this study was to examine the interleukin-8 responses of oral epithelial cells to an oral pro-inflammatory species, Fusobacterium nucleatum, in combination with an oral commensal, Streptococcus cristatus.

MATERIAL AND METHODS

KB, TERT-2, TR146 and SCC15 cells were cocultured with F. nucleatum and S. cristatus, either alone or in combination, at 37 degrees C in 5% CO2 under various conditions. The mRNA expression of interleukin-8 was analyzed by reverse transcription-polymerase chain reaction and protein secretion was measured by enzyme-linked immunosorbent assay.

RESULTS

F. nucleatum alone evoked a potent interleukin-8 response, whereas S. cristatus alone did not induce significant interleukin-8 expression in oral epithelial cells. When present together, S. cristatus attenuated the F. nucleatum-induced interleukin-8 production in the four oral epithelial cell lines to varying degrees. The inhibitory effect of S. cristatus was independent of its viability and its co-aggregation with F. nucleatum, was not related to soluble bacterial products and appeared to require bacterial contact with epithelial cells. Similar effects were seen with several other species of oral streptococci.

CONCLUSION

Our data suggest that S. cristatus may exert immunomodulatory effects on the interleukin-8 response of oral epithelial cells to F. nucleatum challenge.

Brain death affects the hepatic immunogenicity of pigs

OBJECTIVE

The purpose of this study was to observe how the brain-death state affects the hepatic immunogenicity of pigs.

MATERIALS AND METHODS

Twelve healthy ChangBai pigs were allocated randomly to 2 groups: control group (n = 6) with Foley catheter balloon placed intracalvarium for 24 hours only versus brain-death group (n = 6) with brain death for 24 hours. The serum and hepatic tissues were obtained at 6, 12, and 24 hours after the initial confirmation of brain death. Tumor necrosis factor (TNF)-alpha and interleukin (IL)-6 were determined by enzyme-linked immunosorbent assay (ELISA). The major histocompatibility complex class II (MHC-II) was determined by immunohistochemistry, and the intercellular adhesion molecule-1 (ICAM-1) mRNA and monocyte chemotactic protein-1 (MCP-1) mRNA by real-time polymerase chain reaction (PCR).

RESULTS

The serum TNF-alpha and IL-6, MHC-II, ICAM-1 mRNA, and MCP-1 mRNA in hepatic tissues in the brain-death group were higher than in the control group; they all increased with time.

CONCLUSION

Brain death increased liver immunogenicity, which may increase the immune lesion and rejection after transplantation.

Does the relationship between IgE and the CD14 gene depend on ethnicity?

This review considers the data from studies analysing associations between the CD14C-159T single nucleotide polymorphism (SNP) and asthmatic phenotypes and discusses the variability of the conclusions. By searching PubMed and EMBASE for articles on CD14C-159T -related population or family-based association studies, 47 were identified up till September 2007. Collectively, the studies reviewed herein consistently showed population differences in frequencies of the alleles of the SNP, with African descent having the highest C allele frequencies, followed by Caucasians and Asians. The T allele of the SNP was associated with increased sCD14 in some studies but not in others. Inconsistently, the C allele, or even occasionally the T allele, was associated with atopic phenotypes in a population subgroup. There are several explanations for these inconsistencies, including lack of power, linkage disequilibrium, gene-gene interactions, population admixture and gene-environment interactions. If the SNP was associated with functional changes to the coded protein and thus modulating susceptibility to allergic disease, its effect may be modest and dependent on other co-existent, ethnicity-specific, genetic or environmental risk factors.

Cellular distribution of tumour suppressor protein p53 and high-risk human papillomavirus (HPV)-18 E6 fusion protein in wild-type p53 cell lines

Human papillomaviruses (HPVs) are very important pathogens that can be classified as high- and low-risk types based on the lesions they cause. Mucosal high-risk HPV E6 can target and degrade the tumour suppressor p53, hence it is recognized as the major cause of cervical cancer, however, due to a lack of reliable anti-E6 antibodies, the distribution of high-risk HPV E6 protein remains elusive. The present study, therefore, used a mammalian green fluorescent protein (GFP) expression system to express GFP-18 E6 fusion proteins in wild-type p53 cells, SMMC-7721 and HCT116, in order to trace the location and expression of HPV E6 and p53 protein. Following transfection, expression of GFP-18 E6 was found to be located in the nucleus, and endogenous wild-type p53 was also located there with GFP-18 E6.

Desiccant wheels as gas-phase absorption (GPA) air cleaners: evaluation by PTR-MS and sensory assessment

Two experiments were conducted to investigate the use of the co-sorption effect of a desiccant wheel for improving indoor air quality. One experiment was conducted in a climate chamber to investigate the co-sorption effect of a desiccant wheel on the chemical removal of indoor air pollutants; another experiment was conducted in an office room to investigate the resulting effect on perceived air quality. A dehumidifier with a silica-gel desiccant wheel was installed in the ventilation system of the test chamber and office room to treat the recirculation airflow. Human subjects, flooring materials and four pure chemicals (formaldehyde, ethanol, toluene and 1,2-dichloroethane) were used as air pollution sources. Proton-Transfer-Reaction--Mass Spectrometry (PTR-MS) and sensory subjects were used to characterize the effectiveness of chemical and sensory pollution removal of the desiccant wheel. The experiments revealed that all the measured VOCs were removed effectively by the desiccant wheel with an average efficiency of 94% or higher; more than 80% of the sensory pollution load was removed and the percentage dissatisfied with the air quality decreased from 70% to 20%. These results indicate that incorporating a regenerative desiccant wheel in a ventilation system is an efficient way of removing indoor VOCs.

PRACTICAL IMPLICATIONS

This study may lead to the development of new air cleaners and validates a new concept for the design of ventilation systems that can improve indoor air quality and reduce energy consumption.

Rapamycin, mycophenolate mofetil, methylprednisolone, and cytotoxic T-lymphocyte-associated antigen 4 immunoglobulin-based conditioning regimen to induce partial tolerance to hind limb allografts without cytoreductive conditioning

BACKGROUND

Composite tissue allograft transplantation may represent the next frontier in the field of reconstructive surgery. However, the main obstacles precluding the routine use of composite tissue allotransplants are rejection and toxicity associated with life-long immunosuppressive therapy. In this study, we investigated a nontoxic immunosuppressant and cytotoxic T-lymphocyte-associated antigen 4 immunoglobulin (CTLA4-Ig)-based protocol to induce donor-specific tolerance to hind limb allografts in rats.

METHODS

Fully mismatched, 4- to 10-week-old Brown Norway (BN, RT1n) and Lewis (RT1) rats were used as cell/organ donors and recipients, respectively. Recipients were treated with CTLA4-Ig (2 mg/kg/d) on days -30, -28, -26, -24, and -22, rapamycin, mycophenolate mofetil, and methylprednisolone (RAPA/MMF/MP) combined therapy (from days -30 to day 100), a single dose of anti-lymphocyte serum (10 mg, on day -30), and donor bone marrow (10 x 10(7) T-cell-depleted cells) transplantation (BMT, on day -30). Thirty days after BMT, chimeric animals received hind limb allotransplantations (on day 0). The RAPA/MMF/MP combined therapy was changed to Cyclosporine (CsA, 8 mg/kg/d) on day 100 and maintained thereafter at this level.

RESULTS

Hematopoietic chimerism of 17.6 +/- 9.5% at day 0, was stable (15.2 +/- 5.6%) at 230 days post-BMT; there was no sign of graft-versus-host disease. Chimeric recipients (Lewis) permanently accepted (>200 days) donor (BN)-specific (RT11, n = 6) hind limbs, yet rapidly rejected (20 +/- 2 days) third-party hind limbs (Wistar Furth [WF]). Lymphocytes of graft-tolerant animals demonstrated hyporesponsiveness in mixed lymphocyte cultures in a donor-specific manner. Tolerant graft histology showed no signs of acute and chronic rejection.

CONCLUSIONS

The immunosuppressant and CTLA4-Ig-based conditioning regimen with donor BMT produced mixed chimerism and induced partial donor-specific tolerance to hind limb allografts.

Attenuation of seizure in P77PMC rats with an HSV-vector expressing IL-1ra in brain

Cloned human IL-1ra (IL-1 receptor antagonist, IL-1ra) cDNA is inserted into pHSVLac, resulting in recombinant named pHSV-IL-1ra. pHSVLac and pHSV-IL-lra were packaged into HSV-1 particles using HSV-1 ts K as helper virus. The results showed that: (i) vero cell infected by pHSV-IL-1ra particles showed IL-1ra expression; expression of beta-galactosidase is observed in meninges and some neurons closed to ventricular and maintained for 8 weeks in rats after intracerebroventricular injection of pHSV-IL-1ra particles; (ii) transgenic expression of IL-lra by pHSVIL-lra injection significantly inhibited seizure attacks of P77PMC rat. These studies indicate that HSV-1 vector expressing IL-1ra in brain attenuated seizure attacks of P77PMC rat.

Recombination with coat protein transgene in a complementation system based onCucumber mosaic virus (CMV)

In order to study the feasibility ofCucumber mosaic virus (CMV) as an expression vector, the full-length cDNA of RNA 3 from strain SD was cloned and the sequence around the start codon of the coat protein (CP) gene was modified to create anNsi I site for insertion of foreign genes. The CP gene was replaced by the green fluorescent protein (GFP) gene. The cDNAs of Fny RNAs 1 and 2 and the chimeric SD RNA 3 were cloned between the modified 35S promoter and terminator. Tobacco protoplasts were transfected with a mixture of the viral cDNAs containing 35S promoter and terminator as a replacement vector and expressed GFP. A complementation system was established when the replacement vector was inoculated onto the transgenic tobacco plants expressing SD-CMV CP. GFP was detected in the inoculated leaves in 5 of 18 tested plants and in the first upper systemic leaf of one of the 5 plants ten days after inoculation. However, no GFP could be detected in all the plants one month after inoculation. Recombination between the CMV vector and the CP transgene was proved by retro-transcriptional polymerase chain reaction (RT-PCR) and verified by DNA sequencing. Our results argue against the feasibility of the CMV-based replacement vector trans-complemented by the CP transgene, and at the same time, enlighten ways to improve the CMV-based expression vector and the biosafety of CMV CP-mediated virus resistant transgenic plants.

Negative effects of chronic oral chlorpromazine and olanzapine treatment on the performance of tasks designed to assess spatial learning and working memory in rats

Learning potential and memory capacity are factors that strongly predict the level of rehabilitation and the long-term functional outcome in patients with schizophrenia. Unfortunately, however, the effects of antipsychotic drugs (i.e. the primary treatments for schizophrenia) on these components of cognition are unclear, particularly when they are administered chronically (i.e. a standard clinical practice). In this rodent study we evaluated the effects of different time periods (ranging from 2 weeks to 6 months) of oral treatment with the first generation antipsychotic chlorpromazine (10.0 mg/kg/day), or the second generation antipsychotic olanzapine (10.0 mg/kg/day) on the repeated acquisition of a water maze task (i.e. a method of assessing spatial learning potential in a repeated testing format). We assessed locomotor function (in an open field) and employed a radial arm maze (RAM) task to assess antipsychotic effects (5.0 and 10.0 mg/kg/day doses) on spatial working memory during the treatment period between 15 days and 2 months. Finally, we conducted experiments using liquid chromatography/tandem mass spectrometry (LC-MS/MS) to evaluate the therapeutic relevance of our method of drug delivery (oral administration in drinking water). In the water maze experiments, both antipsychotics were associated with impairments in acquisition in the earlier test sessions that could eventually be overcome with repeated testing while olanzapine also impaired retention in probe trials. Both antipsychotics were also associated with impairments in delayed non-match-to-position trials in the RAM and some impairments of motor function (especially in the case of olanzapine) as indicated by slightly reduced swim speeds in the water maze and decreased activity in some components of the open field assessment. Finally, LC-MS/MS studies indicated that the method of antipsychotic administration generated clinically relevant plasma levels in the rat. These animal data indicate that chronic oral treatment with chlorpromazine or olanzapine can impair the performance of tasks designed to assess specific components of cognition that are affected in schizophrenia.