Increased expression of AMPA receptor subunits in the nucleus of the solitary tract in the spontaneously hypertensive rat

The expression of alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptor subunits GluR1-4 in the nucleus of the solitary tract (NTS) of adult Wistar rats was examined by polymerase chain reaction (PCR), and the neuronal localisation of these receptor subunits in the NTS were confirmed by immunohistochemistry using subunit-specific antibodies. Semi-quantitative PCR was used to investigate differences in AMPA receptor subunit expression between spontaneously hypertensive rats (SH) and age-matched normotensive Wistar Kyoto rats (WKY). All four receptor subunits were expressed in both strains, but compared to WKY, total AMPA receptor and the GluR3 mRNA expressions were significantly higher in SH. No differences were detected in cDNA form the cerebral cortex or cerebellum. Immunolabelling for GluRs 1, 2 and 2/3 in the neuropil relative to neuronal somata in the cardioregulatory areas of the NTS appeared to be increased in SH, with an overall increase in the density of GluR2/3 labelling in the medial and commissural NTS of SH. These results indicate a possible role for changes in AMPA receptor subunit expression in NTS neurones, involving an increase in GluR3 associated with development of hypertension in SH.     

Co-occurrence of Wilson's disease and glioblastoma multiforme--is it a chance association?

We report a patient with glioblastoma multiforme who was subsequently diagnosed to have Wilson's disease. Immunohistochemical studies of the tumor revealed high (> 60%) labeling index for p53 and Rb retinoblastoma protein. Whether this association is like the co-occurrence of retinoblastoma and Wilson's disease due to possible somatic mutation in chromosome 13 needs to be explored.     

Repeated episodes of endosulfan poisoning

INTRODUCTION: A number of families in a rural area of Jabalpur District (Madhya Pradesh), India, were affected by repeated episodes of convulsive illness over a period of three weeks. The aim of this investigation was to determine the cause of the illness. METHODS: The investigation included a house-to-house survey, interviews of affected families, discussions with treating physicians, and examination of hospital records. Endosulfan poisoning was suspected as many villagers were using empty pesticide containers for food storage. To confirm this, our team collected blood and food samples, which were transported to the laboratory and analyzed with GC-ECD. RESULTS: Thirty-six persons of all age groups had illness of varying severity over a period of three weeks. In the first week, due to superstitions and lack of treatment, three children died. In the second week, symptomatic treatment of affected persons in a district hospital led to recovery but recurrence of convulsive episodes occurred after the return home. In the third week, 10 people were again hospitalized in a teaching hospital. Investigations carried out in this hospital ruled out infective etiology but no facilities were available for chemical analysis. All persons responded to symptomatic treatment. The blood and food samples analyzed by our team showed presence of endosulfan, which was confirmed by GCMS. One of the food items (Laddu) prepared from wheat flour was found to contain 676 ppm of alpha-endosulfan. CONCLUSIONS: Contamination of wheat grains or flour with endosulfan and its consumption over a period of time was the most likely cause of repeated episodes of convulsions, but the exact reason for this contamination could not be determined. This report highlights the unsafe disposal of pesticide containers by illiterate farm workers, superstitions leading to delay in treatment, and susceptibility of children to endosulfan.     

N-Methyl-N'-nitro-N-nitrosoguanidine-induced senescence-like growth arrest in colon cancer cells is associated with loss of adenomatous polyposis coli protein,microtubule organization,and telomeric DNA

Background  

Cellular senescence is a state in which mammalian cells enter into an irreversible growth arrest and altered biological functions. The senescence response in mammalian cells can be elicited by DNA-damaging agents. In the present study we report that the DNA-damaging agent N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) is able to induce senescence in the HCT-116 colon cancer cell line.     

Generation of murine monoclonal antibodies to Haemophilus influenzae type b capsular polysaccharide by in vivo immunization

Haemophilus influenzae type b (Hib) is a pathogenic gram-negative bacterium associated with human disease, especially in young children. Protective immune response to Hib results from antibodies developed against the polyribosylribitol phosphate (PRP) capsular polysaccharide of the bacterium. Several investigators in the study of immune response to Hib have produced human monoclonal antibodies to PRP. Only two previous groups have reported the generation of murine anti-PRP monoclonal antibodies using either immunizing mice with inactivated Hib bacteria or a combination of in vivo and in vitro immunization of mice with PRP conjugate antigen (PRP-D). In this present study, we generated murine anti-PRP monoclonal antibody secreting hybridomas for the first time by simple in vivo immunization with PRP conjugate antigen (PRP-T). The anti-PRP antibodies from one hybridoma clone (B10) are further characterized and potential applications are discussed.     

Atrial natriuretic peptide gene transfer by means of intranasal administration attenuates airway reactivity in a mouse model of allergic sensitization

Atrial natriuretic peptide (ANP) is a bronchodilator; however, the short half-life of ANP in vivo limited its therapeutic utility to treat asthma. The efficacy of intranasally administered plasmid DNA-expressing ANP (pANP; amino acid 99-126; Acc. No. XM131840) on the prevention of allergen-induced airway hyperresponsiveness (AHR) was examined in this study by using a mouse model of asthma. Ovalbumin-sensitized mice were treated with pANP versus control plasmids, and AHR was monitored after ovalbumin challenge for 5 weeks on 10-day intervals starting 4 days after gene transfer. Mice administered pANP demonstrated significantly less AHR for 20 days after treatment. The results demonstrate that pANP gene transfer protects against AHR and might be useful in the treatment of asthma.     

Restoration of silenced Peutz-Jeghers syndrome gene, LKB1, induces apoptosis in pancreatic carcinoma cells

Germ line mutations of the LKB1 tumor suppressor gene lead to Peutz-Jeghers syndrome (PJS) with a predisposition to cancer. Previous reports suggest that inactivation of this tumor-suppressor gene plays a role in the pathogenesis of gastrointestinal hamartomas as well as several cancers, including adenocarcinoma of the pancreas. Here, we have shown that LKB1 gene is silenced in the pancreatic cancer cell line AsPC-1, but can be recovered by treatment with the methylation inhibitor, 5-aza-2'-deoxycytidine (5aza2dC). Restoring the level of LKB1 through gene transfer initiated mitochondria-mediated apoptosis in AsPC-1 cells, as evidenced by the release of cytochrome c from the mitochondria. By confocal microscopy as well as biochemical fractionation, we demonstrate that LKB1 is present in the nuclear and mitochondrial compartments of pancreatic cancer cells. Our observations also indicate that although functional p53 is absent, the p53 kin, p73, is inducible by doxorubicin in AsPC-1 cells. This suggests that LKB1-induced apoptosis is p53 independent but might be p73-mediated in the pancreatic tumor cell line, AsPC-1.