Role of GABA within the nucleus tractus solitarii in the hypoxic ventilatory decline of awake rats

The purpose of this study was to examine our hypothesis that gamma-aminobutyric acid (GABA) in the nucleus tractus solitarii (NTS) may be related to the hypoxic ventilatory decline (HVD) and that chemoreceptor stimulation was essential to activate this mechanism. We used unanesthetized, freely moving rats in this study. An in vivo microdialysis technique was used to measure the extracellular GABA concentration ([GABA]o), and an in vivo microinjection technique was used to examine the effects of the GABA agonists and antagonists on the ventilation during hypoxia. The GABA agonists injected into the NTS attenuated the ventilation during hypoxia. By hypoxic exposure, [GABA]o was increased during the HVD. However, by carotid body denervation (CBD), this GABA increase was abolished. Although GABA antagonists microinjected into the NTS during the HVD phase significantly increased the depressed ventilation, this effect on the ventilation was abolished by CBD. These results suggest that the GABA in the NTS has a pivotal role in the HVD and that this mechanism is not activated without chemoreceptor stimulation.     

Carcinoma in chronic pressure sores: a fulminant disease process

Four cases of squamous cell carcinoma arising from chronic pressure sores in paraplegic and tetraplegic patients are presented and the literature reviewed. These pressure-sore carcinomas are characterized by a shorter latency period and a fulminant clinical course with a very high metastatic rate. Very aggressive treatment including even hemicorporectomy must be considered if a cure is to be achieved.     

From pathogen genomes to host plant processes: the power of plant parasitic oomycetes

Recent pathogenomic research on plant parasitic oomycete effector function and plant host responses has resulted in major conceptual advances in plant pathology, which has been possible thanks to the availability of genome sequences.     

Detection of Helminth Eggs and Identification of Hookworm Species in Stray Cats,Dogs and Soil from Klang Valley,Malaysia

The present study was conducted to determine the prevalence of helminth eggs excreted in the faeces of stray cats, dogs and in soil samples. A total of 505 fresh samples of faeces (from 227 dogs and 152 cats) and soil were collected. The egg stage was detected via microscopy after the application of formalin–ether concentration technique. Genomic DNA was extracted from the samples containing hookworm eggs and used for further identification to the species level using real-time polymerase chain reaction coupled with high resolution melting analysis. Microscopic observation showed that the overall prevalence of helminth eggs among stray cats and dogs was 75.7% (95% CI = 71.2%–79.9%), in which 87.7% of dogs and 57.9% of cats were infected with at least one parasite genus. Five genera of heliminth eggs were detected in the faecal samples, including hookworms (46.4%), Toxocara (11.1%), Trichuris (8.4%), Spirometra (7.4%) and Ascaris (2.4%). The prevalence of helminth infections among stray dogs was significantly higher than that among stray cats (p < 0.001). Only three genera of helminths were detected in soil samples with the prevalence of 23% (95% CI = 15.1%–31%), consisting of hookworms (16.6%), Ascaris (4%) and Toxocara (2.4%). The molecular identification of hookworm species revealed that Ancylostoma ceylanicum was dominant in both faecal and soil samples. The dog hookworm, Ancylostoma caninum, was also detected among cats, which is the first such occurrence reported in Malaysia till date. This finding indicated that there was a cross-infection of A. caninum between stray cats and dogs because of their coexistent within human communities. Taken together, these data suggest the potential role of stray cats and dogs as being the main sources of environmental contamination as well as for human infections.     

Health and Human Rights in Eastern Myanmar after the Political Transition: A Population-Based Assessment Using Multistaged Household Cluster Sampling

BackgroundMyanmar transitioned to a nominally civilian parliamentary government in March 2011. Qualitative reports suggest that exposure to violence and displacement has declined while international assistance for health services has increased. An assessment of the impact of these changes on the health and human rights situation has not been published.ConclusionThis large survey of health and human rights demonstrates that two years after political transition, vulnerable populations of eastern Myanmar are less likely to experience human rights violations compared to previous surveys. However, access to health services remains constrained, and risk of disease and death remains higher than the country as a whole. Efforts to address these poor health indicators should prioritize support for populations that remain outside the scope of most formal government and donor programs.     

Maleic Acid – but Not Structurally Related Methylmalonic Acid – Interrupts Energy Metabolism by Impaired Calcium Homeostasis

Maleic acid (MA) has been shown to induce Fanconi syndrome via disturbance of renal energy homeostasis, though the underlying pathomechanism is still under debate. Our study aimed to examine the pathomechanism underlying maleic acid-induced nephrotoxicity. Methylmalonic acid (MMA) is structurally similar to MA and accumulates in patients affected with methymalonic aciduria, a defect in the degradation of branched-chain amino acids, odd-chain fatty acids and cholesterol, which is associated with the development of tubulointerstitial nephritis resulting in chronic renal failure. We therefore used MMA application as a control experiment in our study and stressed hPTECs with MA and MMA to further validate the specificity of our findings. MMA did not show any toxic effects on proximal tubule cells, whereas maleic acid induced concentration-dependent and time-dependent cell death shown by increased lactate dehydrogenase release as well as ethidium homodimer and calcein acetoxymethyl ester staining. The toxic effect of MA was blocked by administration of single amino acids, in particular L-alanine and L-glutamate. MA application further resulted in severe impairment of cellular energy homeostasis on the level of glycolysis, respiratory chain, and citric acid cycle resulting in ATP depletion. As underlying mechanism we could identify disturbance of calcium homeostasis. MA toxicity was critically dependent on calcium levels in culture medium and blocked by the extra- and intracellular calcium chelators EGTA and BAPTA-AM respectively. Moreover, MA-induced cell death was associated with activation of calcium-dependent calpain proteases. In summary, our study shows a comprehensive pathomechanistic concept for MA-induced dysfunction and damage of human proximal tubule cells.     

First hominoid from the Late Miocene of the Irrawaddy Formation (Myanmar)

For over a century, a Neogene fossil mammal fauna has been known in the Irrawaddy Formation in central Myanmar. Unfortunately, the lack of accurately located fossiliferous sites and the absence of hominoid fossils have impeded paleontological studies. Here we describe the first hominoid found in Myanmar together with a Hipparion (s.l.) associated mammal fauna from Irrawaddy Formation deposits dated between 10.4 and 8.8 Ma by biochronology and magnetostratigraphy. This hominoid documents a new species of Khoratpithecus, increasing thereby the Miocene diversity of southern Asian hominoids. The composition of the associated fauna as well as stable isotope data on Hipparion (s.l.) indicate that it inhabited an evergreen forest in a C3-plant environment. Our results enlighten that late Miocene hominoids were more regionally diversified than other large mammals, pointing towards regionally-bounded evolution of the representatives of this group in Southeast Asia. The Irrawaddy Formation, with its extensive outcrops and long temporal range, has a great potential for improving our knowledge of hominoid evolution in Asia.     

An innovative approach for the characterization of the isoforms of a monoclonal antibody product

Protein biopharmaceuticals, such as monoclonal antibodies (mAbs) are widely used for the prevention and treatment of various diseases. The complex and lengthy upstream and downstream production methods of the antibodies make them susceptible to physical and chemical modifications. Several IgG1 immunoglobulins are used as medical agents for the treatment of colon, breast and head and neck cancers, and at least four to eight isoforms exist in the products. The regulatory agencies understand the complex nature of the antibody molecules and allow the manufactures to set their own specifications for lot release, provided the safety and efficacy of the products are established in animal models prior to clinical trials. During the manufacture of a mAb product, we observed lot-to-lot variability in the isoform content and, although the variability is within the set specifications for lot release, made attempts to gain mechanistic insight by isolating and characterizing the individual isoforms. Matrix-assisted laser desorption/ionization (MALDI) and liquid chromatography (LC)/mass spectrometry (MS)/MS analyses of the isolated isoforms indicate that this variability is caused by sialic acid content, as well as truncation of C-terminal lysine of the individual isoforms. Sialidase and carboxypeptidase treatment of the product confirm the observations made by MALDI and LC/MS/MS.Key words: IgG1, isoforms, charge heterogeneity, monoclonal antibody, glycosylation, silaic acidMonoclonal antibodies (mAbs) are used as medical agents to treat a variety of diseases including cancer, cardiovascular diseases and blood disorders.^1–3 Although a few IgG2 (e.g., panitumumab, denosumab) and IgG4 antibody molecules are in the market, most of the approved products are IgG1 molecules. IgG1 antibodies are glycoproteins with a conserved N-glycosylation site at Asn 297. Glycosylation influences the biological functions, such as antibody dependent cell-mediated cytotoxicity (ADCC) and complement dependent cytotoxicity (CDC) of the antibodies. The oligosaccharides present in the IgG1 molecules are heterogeneous due to the presence of various sugar residues, including sialic acid, galactose, N-acetylglucasmine and fucose residues. Molecular alterations in antibodies can take place at every stage of manufacturing: upstream and downstream processing, formulation and storage. These alterations can take place enzymatically or non-enzymatically and may produce charge or size heterogeneity. Deamidation, proteolytic fragmentation, oxidation, disulfide bond shuffling and glycosylation are the most common modifications that occur during the production of protein therapeutics.^4–7 These modifications can reduce the biological activity and may induce immunogenicity in patients. Hence, the regulatory agencies require a comprehensive characterization of the structural integrity, purity and stability of the protein therapeutics.⁸To date, eight chimeric, humanized and human IgG1 mAbs have been approved in the United States, Europe, as well as other countries, for the treatment of several types of cancers.^9–12 One such molecule produced at ImClone has two N-glycosylation sites and at least six to eight isoforms with isoelectric points (pIs) between 7.9–8.9 are present in this product. Although techniques such as ion exchange chromatography (IEX) and capillary isoelectic focusing (IEF) are available for the separation and characterization of charge varients,^13,14 we were not successful in separating the individual isoforms with these techniques from the IgG1 product used in this investigation. The peaks from IEX showed the presence of multiple bands on IEF. Hence, an alternative approach was used to isolate each isoform of this IgG1 product, and we demonstrated the involvement of sialic acid and C-terminal lysine as the root causes for lot-to-lot variation observed during the production of this molecule. The method is fast and very effective in separating isoforms with a difference in the pI values < 0.1.     

Late Triassic and Lower Jurassic Foraminifera of the carbonate platform of the Beyaz Aladağ Group (Eastern Taurus,Turkey): New stratigraphic implications

Foraminifera have proven to be reliable biostratigraphic indicators. Accordingly, Triassic and Early Jurassic benthic Foraminifera allow us to define a biostratigraphic zonation within the carbonate platform of Kayseri (Yahyal?), Göksun (Kahramanmara?) and Sivas (Delikta?) regions in the Eastern Taurus (Ceviz, Alada?, Kaman and Felfan Mountains). Seven new stratigraphic sections are described in detail and the first precise inventory and illustration of the benthic foraminifer assemblages from the Triassic successions are presented over a large geographic area. The stratigraphic and palaeontological features of the Lower Mesozoic carbonate units of these mountains include several synchronous transgressive–regressive events that suggest continuity of the Lower Mesozoic environments over a large parautochthonous Taurus zone. Palaeogeographic considerations about the Eastern Taurus carbonates are given, evidencing three stages of development underwent by the studied area: 1) a stable continental margin from Lower Triassic to Lower Cretaceous; 2) a dismantling of the continental margin and first emplacement of ophiolites in the Upper Cretaceous; and 3) a deformation of the continental margin and emplacement of the Peridotite Nappe in the uppermost Cretaceous (Maastrichtian).