NF-kappa B inactivation converts a hepatocyte cell line TNF-alpha response from proliferation to apoptosis

Toxins convertthe hepatocellular response to tumor necrosis factor- (TNF-)stimulation from proliferation to cell death, suggesting thathepatotoxins somehow sensitize hepatocytes to TNF- toxicity. Becausenuclear factor-B (NF-B) activation confers resistance to TNF-cytotoxicity in nonhepatic cells, the possibility that toxin-inducedsensitization to TNF- killing results from inhibition ofNF-B-dependent gene expression was examined in the RALA rathepatocyte cell line sensitized to TNF- cytotoxicity by actinomycinD (ActD). ActD did not affect TNF--induced hepatocyte NF-Bactivation but decreased NF-B-dependent gene expression. Expressionof an IB superrepressor rendered RALA hepatocytes sensitive toTNF--induced apoptosis in the absence of ActD. Apoptosis was blockedby caspase inhibitors, and TNF- treatment led to activation ofcaspase-2, caspase-3, and caspase-8 only when NF-B activation wasblocked. Although apoptosis was blocked by the NF-B-dependent factornitric oxide (NO), inhibition of endogenous NO production did notsensitize cells to TNF--induced cytotoxicity. Thus NF-Bactivation is the critical intracellular signal that determines whetherTNF- stimulates hepatocyte proliferation or apoptosis. Althoughexogenous NO blocks RALA hepatocyte TNF- cytotoxicity, endogenousproduction of NO is not the mechanism by which NF-B activationinhibits this death pathway.

     

Cerebrospinal Fluid from Sporadic Amyotrophic Lateral Sclerosis Patients Induces Mitochondrial and Lysosomal Dysfunction

In our laboratory, we have developed (1) an in vitro model of sporadic Amyotrophic Lateral Sclerosis (sALS) involving exposure of motor neurons to cerebrospinal fluid (CSF) from sALS patients and (2) an in vivo model involving intrathecal injection of sALS-CSF into rat pups. In the current study, we observed that spinal cord extract from the in vivo sALS model displayed elevated reactive oxygen species (ROS) and mitochondrial dysfunction. Quantitative proteomic analysis of sub-cellular fractions from spinal cord of the in vivo sALS model revealed down-regulation of 35 mitochondrial proteins and 4 lysosomal proteins. Many of the down-regulated mitochondrial proteins contribute to alterations in respiratory chain complexes and organellar morphology. Down-regulated lysosomal proteins Hexosaminidase, Sialidase and Aryl sulfatase also displayed lowered enzyme activity, thus validating the mass spectrometry data. Proteomic analysis and validation by western blot indicated that sALS-CSF induced the over-expression of the pro-apoptotic mitochondrial protein BNIP3L. In the in vitro model, sALS-CSF induced neurotoxicity and elevated ROS, while it lowered the mitochondrial membrane potential in rat spinal cord mitochondria in the in vivo model. Ultra structural alterations were evident in mitochondria of cultured motor neurons exposed to ALS-CSF. These observations indicate the first line evidence that sALS-CSF mediated mitochondrial and lysosomal defects collectively contribute to the pathogenesis underlying sALS.     

Lymph node metastasis of soft tissue tumors: a cytomorphologic study

OBJECTIVE: To study the frequency of regional lymph node metastasis of soft tissue tumors (STT) and to evaluate the utility of fine needle aspiration cytology (FNAC) as an initial investigative modality. STUDY DESIGN: A prospective and retrospective study of over 6 years (1998-2004) was performed to look for frequency of STT metastasizing to lymph nodes. FNAC of enlarged nodes was performed as a routine outpatient procedure after obtaining complete clinical details. Histopathology and immunohistochemistry were correlated where available. RESULTS: Lymph node enlargement was seen in 23 of 241 patients with STTs, of which 19 cases showed involvement (7.88%), synchronous with primary in 12 cases and metachronous in 7 cases. The most common sites of primary tumor were the lower extremity and head and neck region with involved regional lymph nodes. STTs commonly involving lymph nodes were rhabdomyosarcoma and extraskeletal Ewing's/primitive neuroectodermal tumor (PNET); other rare tumors included malignant granular cell tumor, epithelioid hemangioendothelioma, mediastinal ganglioneuroblastoma, angiosarcoma and epithelioid sarcoma. CONCLUSION: Lymph node aspirates should be examined for alien cells, particularly smears that are paucicellular and demonstrate cystic change. Lymph node metastasis of STT is rare and influences staging, treatment and prognosis. Enlarged regional nodes should be examined with FNAC.     

Prevalence of diarrhoeal pathogens among children under five years of age with and without diarrhoea in Guinea-Bissau

BackgroundChildhood diarrhoea, a major cause of morbidity and mortality in low-income regions, remains scarcely studied in many countries, such as Guinea-Bissau. Stool sample drying enables later qPCR analyses of pathogens without concern about electricity shortages.MethodsDried stool samples of children under five years treated at the Bandim Health Centre in Bissau, Guinea-Bissau were screened by qPCR for nine enteric bacteria, five viruses, and four parasites. The findings of children having and not having diarrhoea were compared in age groups 0–11 and 12–59 months.ResultsOf the 429 children– 228 with and 201 without diarrhoea– 96.9% and 93.5% had bacterial, 62.7% and 44.3% viral, and 52.6% and 48.3% parasitic pathogen findings, respectively. Enteroaggregarive Escherichia coli (EAEC; 60.5% versus 66.7%), enteropathogenic E. coli (EPEC; 61.4% versus 62.7%), Campylobacter (53.2% versus 51.8%), and enterotoxigenic E. coli (ETEC; 54.4% versus 44.3%) were the most common bacterial pathogens. Diarrhoea was associated with enteroinvasive E. coli (EIEC)/Shigella (63.3%), ETEC (54.4%), astrovirus (75.0%), norovirus GII (72.6%) and Cryptosporidium (71.2%). The only pathogen associated with severe diarrhoea was EIEC/Shigella (p<0.001). EAEC was found more frequent among the infants, and EIEC/Shigella, Giardia duodenalis and Dientamoeba fragilis among the older children.ConclusionsStool pathogens proved common among all the children regardless of them having diarrhoea or not.     

Forms and Mobility of Sediment Phosphorus in Shallow Eutrophic Lake Võrtsjärv (Estonia)

The surficial sediment (0–10 cm) of shallow eutrophic Lake Võrtsjärv (Estonia) was characterized by an acid insoluble residue of 50% dry weight and low nutrient, Fe and Mn content. Among phosphorus (P) fractions (Hieltjes and Lijklema , 1980), NaOH-NRP amounted on an average to 50%, HCl-RP to 30%, NaOH-RP to 16%, and NH₄Cl-RP to 4% of their sum. Seasonal changes in sediment P content were inconsistent with mass balance calculations and could be attributed to sediment redistribution caused by decreasing water level. High Fe/P ratio (26–30) and the aeration of surficial sediment by frequent resuspension kept phosphate adsorbed. Low pore-water SRP (commonly <10 μg l⁻¹) usually prevented phosphate release from surficial sediment. However, a storm in September 1996 (max. wind speed 16 m s⁻¹) which coincided with the extremely low water level in the lake (mean depth 1.44 m), denuded deeper anoxic sediment layers and caused a SRP release of 193 mg P m⁻² d⁻¹.     

内蒙古大庙中新世小哺乳动物化石埋藏学研究

捕食是小哺乳动物死亡最常见的原因,也导致被捕食动物遗骸发生明显改变.动物死亡后的风化、踩踏、搬运等过程也会改变动物的骨骼并影响到化石组合的形成.本文研究了内蒙古大庙三个中新世化石地点,时代从早中新世到晚中新世早期(约21～11.6 Ma).通过分析各小哺乳动物化石组合的沉积背景以及埋藏学特征识别化石埋藏的主要成因.结果显示出捕食是三个地点小哺乳动物化石埋藏的基本成因,而在两个年轻的地点中也有流水搬运与可能的踩踏因素的叠加.三个地点可能存在不一样的捕食者:早中新世地点以猫头鹰捕食为主,中、晚中新世地点则以日间活动的鸟类或哺乳类为主要捕食者.研究还显示小哺乳动物的系统发掘是可行的,在一定程度上可以减少采样过程中产生的破坏.     

Local and regional processes in low-productive mountain plant communities: the roles of seed and microsite limitation in relation to grazing

It is becoming widely accepted that plant community structure is determined not only by local scale factors, but that regional factors may play considerable role. The research studying the associated processes in different environments with different species assemblages is still limited. We conducted a two-year seed sowing experiment to test whether a plant community in a low-productive mountain snowbed is limited by seed or microsite availability and how these variables depend on natural grazing. In a factorial design, half of the plots received a mixture of seeds of fourteen species naturally occurring at the study site and above ground biomass was removed from half of the plots. These treatments were applied to plots with long term grazer exclosures and to plots accessible to grazers. Both sowing and biomass removal increased the number of seedlings, the species richness of seedlings and total species richness. The number of seedlings was higher in open plots than in exclosures in the second year. Both seedling richness and total species richness were higher in open plots. Seedling recruitment was negatively related to the amount of above ground biomass and positively to the initial species richness. These results suggest that even fairly low-productive environments can be both seed and microsite limited and that these depend on grazing pressure. Natural grazing by mammal herbivores (e.g. lemmings and reindeer) favours species colonization and seedling emergence. Low-productive mountain snowbeds are prone to colonization from the local species pool and even high species richness may not constrain ingression of new species.