Tumor-targeting bacterial therapy with amino acid auxotrophs of GFP-expressing Salmonella typhimurium

Here we report a genetically modified bacteria strain, Salmonella typhimurium A1, selected for anticancer activity in vivo. The strain grows in tumor xenografts. In sharp contrast, normal tissue is cleared of these bacteria even in immunodeficient athymic mice. S. typhimurium A1 is auxotrophic (Leu/Arg-dependent) but apparently receives sufficient support from the neoplastic tissue to grow locally. Whether additional genetic lesions are present is not known. In in vitro infection, the GFP-expressing bacteria grew in the cytoplasm of PC-3 human prostate cancer cells and caused nuclear destruction. These effects were visualized in cells labeled with GFP in the nucleus and red fluorescent protein in the cytoplasm. In vivo, the bacteria caused tumor inhibition and regression of xenografts visualized by whole-body imaging. The bacteria, introduced i.v. or intratumorally, invaded and replicated intracellularly in PC-3 prostate cancer cells labeled with red fluorescent protein grafted into nude mice. By day 15, S. typhimurium A1 was undetectable in the liver, lung, spleen, and kidney, but it continued to proliferate in the PC-3 tumor, which stopped growing. When the bacteria were injected intratumorally, the tumor completely regressed by day 20. There were no obvious adverse effects on the host when the bacteria were injected by either route. The S. typhimurium A1 strain grew throughout the tumor, including viable malignant tissue. This result is in marked contrast to bacteria previously tried for cancer therapy that were confined to necrotic areas of the tumor, which may account, in part, for the strain's unique antitumor efficacy.     

Effects of enhanced viscosity on canine gastric and intestinal motility

BACKGROUND AND AIM: The aim of this study was to investigate the effect of enhanced viscosity on gastric emptying and gastrointestinal motor and myoelectrical activities in dogs. METHOD: The study was performed in eight healthy female hound dogs chronically implanted with four pairs of gastric and two pairs of intestinal serosal electrodes and a duodenal fistula. Each dog was studied in three sessions and fed with three test meals with different viscosity. Gastric emptying was monitored for 2 h simultaneously with gastric and intestinal myoelectrical recordings. RESULTS: The liquid test meal containing either 0.78% or 1.21% of galactomannan significantly delayed gastric emptying but had no effect on postprandial blood glucose levels in comparison with the meal containing no galactomannan. The liquid test meal containing either 0.78% or 1.21% of galactomannan significantly increased the frequency and strength of intestinal motility but had no effect on intestinal slow wave rhythms. The product with enhanced viscosity had no effect on gastric motor activity or gastric slow waves. CONCLUSION: It was concluded that enhanced viscosity delays gastric emptying, increases postprandial intestinal but not gastric motility, and has no effects on gastric or intestinal slow waves.     

Novel brain reactive autoantibodies: prevalence in systemic lupus erythematosus and association with psychoses and seizures

Autoantibodies can cause neuropsychiatric manifestations in lupus patients by altering the physiological function of neuronal cells. In this study, we identified Brain Reactive Autoantibodies (BRAAs) against murine neuronal membrane proteins (M.W. 27.5 and 29.5 kD) and found them correlating with psychosis and/or seizures in lupus patients. They were specific to neuronal membrane tissues of mammalian origin and are significantly associated with psychosis and/or seizures (p<0.0001). These membrane proteins mass spectrometry profiles did not match to any published protein sequences. These BRAAs may play important roles in the pathophysiology of neuropsychiatric lupus.     

Quantitative proteomic analysis of mitochondrial proteins: relevance to Lewy body formation and Parkinson's disease

The mechanisms underlying Parkinson's disease (PD) and Lewy body (LB) formation, a pathological hallmark of PD, are incompletely understood; however, mitochondrial dysfunction is likely to be at least partially responsible. To study the processes that might be related to nigral neurodegeneration and LB formation, we employed nonbiased quantitative proteomics with isotope-coded affinity tag (ICAT) to compare the mitochondrial protein profiles in the substantia nigra (SN) between controls and mice treated chronically with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), a potent mitochondrial toxicant, and an adjuvant, probenecid (prob), for 5 weeks, which produced selective nigrostriatal neurodegeneration with formation of LB-like cytoplasmic inclusions in the remaining nigral neurons. This method identified a total of more than 300 proteins; of these proteins, more than 100 displayed significant changes in relative abundance in the MPTP/prob-treated mice compared to the controls. We validated one of these proteins, DJ-1, whose mutation has been implicated in familial PD, with Western blot analysis, followed by immunohistochemical studies of its distribution in the SN in relation to cytoplasmic inclusions in mice, as well as in classical LBs in PD patients. The results demonstrated that DJ-1 was not only colocalized with alpha-synuclein in dopaminergic neurons but also to cytoplasmic inclusions in mice treated with MPTP/prob. In addition, DJ-1 was present in the halo but not in the core of classical LBs in patients with PD. Our findings suggested that DJ-1 might play an important role in mitochondrial dysfunction, as well as LB formation in PD.     

Distinct roles of oxidative stress and antioxidants in the nucleus dorsalis and red nucleus following spinal cord hemisection

Oxidative stress plays an important role in the pathogenesis of neurodegeneration after the acute central nervous system injury. We reported previously that increased nitric oxide (NO) production following spinal cord hemisection tends to lead to neurodegeneration in neurons of the nucleus dorsalis (ND) that normally lacks expression of neuronal NO synthase (nNOS) in opposition to those in the red nucleus (RN) that constitutively expresses nNOS. We wondered whether oxidative stress could be a mechanism underlying this NO involved neurodegeneration. In the present study, we examined oxidative damage evaluated by the presence of 4-hydroxynonenal (HNE) and iron accumulation and expression of putative antioxidant enzymes heme oxygenase-1 (HO-1) and superoxide dismutase (SOD) in neurons of the ND and RN after spinal cord hemisection. We found that HNE expression was induced in neurons of the ipsilateral ND from 1 to 14 days following spinal cord hemisection. Concomitantly, iron staining was seen from 7 to 14 days after lesion. HO-1, however, was only transiently induced in ipsilateral ND neurons between 3 and 7 days after lesion. In contrast to the ND neurons, HNE was undetectable and iron level was unaltered in the RN neurons after spinal cord hemisection. HO-1, SOD-Cu/Zn and SOD-Mn were constitutively expressed in RN neurons, and lesion to the spinal cord did not change their expression. These results suggest that oxidative stress is involved in the degeneration of the lesioned ND neurons; whereas constitutive antioxidant enzymes may protect the RN neurons from oxidative damage.     

Association of COMT Val158Met genotype with executive functioning following traumatic brain injury

Catechol-O-methyltransferase (COMT) is thought to functionally modulate dopamine neurons, thus likely influencing frontal-executive functioning. High enzyme activity (COMT Val) and low enzyme activity (COMT Met) are functional polymorphisms resulting from a G to A transition in exon 4 (codon 158) of the human COMT gene. Decreased cortical dopamine should result in poorer executive functioning. Therefore, the authors hypothesized that individuals with traumatic brain injury (TBI) and the low enzyme activity polymorphism would perform better on tests of executive functioning than individuals with the high enzyme activity polymorphism. One hundred thirteen individuals referred to the Defense and Veterans Brain Injury Center underwent a comprehensive TBI evaluation and were genotyped for the COMT polymorphism. Comparison of mean differences among the COMT genotype groups for several measures of aspects of executive functioning was conducted using analysis of variance (ANOVA) with adjustment for multiple comparisons. Homozygotes for the higher activity allele made more perseverative responses on the Wisconsin Card Sorting Test, while homozygotes for the lower activity allele had the least number of perseverative responses. While it cannot be determined whether TBI influenced the association of COMT Val158Met to executive functioning, these data extend the known relationship of genotype to executive performance seen in healthy comparison subjects and individuals with schizophrenia to individuals with TBI.