Amyloid Precursor Protein (APP) mRNA Level is Higher in the Old Mouse Cerebral Cortex and is Regulated by Sex Steroids

Alzheimer’s disease (AD) is a neurodegenerative disorder characterized by the accumulation of amyloid beta peptides, which are produced by the proteolytic cleavage of amyloid precursor protein (APP). As the incidence of AD is higher in females and sex steroids are implicated in this disease, we have examined the effect of sex steroids (testosterone and 17β-estradiol) on the expression of APP mRNA and protein in the cerebral cortex of adult and old mice of both sexes. Northern blot analysis detected APP mRNA as a single 3.5-kb band and its level is increased in old as compared to adult. Following gonadectomy, its level was upregulated in female mice but downregulated in male mice. Supplementation with testosterone or estradiol decreased its levels in female mice of both ages. Testosterone supplementation increased the mRNA levels in both adult and old male mice. Estrogen supplementation decreased its level in adult but increased in old male mice. Western blot analysis detected APP specific bands ranging from 95 to 125 kD. The level of 95 kDa band representing APP695 protein showed difference in levels with age or hormone treatment. These results provide evidence for increase in APP mRNA level in the cerebral cortex of old mice and its regulation by sex steroids during aging.     

In vivo 19F magnetic resonance spectroscopy and chemical shift imaging of tri-fluoro-nitroimidazole as a potential hypoxia reporter in solid tumors.

PURPOSE: 2-Nitro-alpha-[(2,2,2-trifluoroethoxy)methyl]-imidazole-1-ethanol (TF-MISO) was investigated as a potential noninvasive marker of tissue oxygen levels in tumors using (19)F magnetic resonance spectroscopy (MRS) and (19)F chemical shift imaging. EXPERIMENTAL DESIGNS: In vitro data were obtained using high-performance liquid chromatography on tumor cells incubated under varying oxygen conditions to determine the oxygen-binding characteristics. In vivo data were obtained using a well-characterized hypoxic murine breast tumor (MCa), in addition to studies on a rat prostate tumor model (R3327-AT) implanted in nude mice. Detection of intratumor (19)F signal from TF-MISO was done using MRS for up to 10 h following a 75 mg/kg i.v. injection. Localized distribution of the compound in the implanted MCa tumor has been imaged using slice-selective two-dimensional chemical shift imaging 6 h after injection. RESULTS: The in vitro results showed that TF-MISO preferentially accumulates in cells incubated under anoxic conditions. The in vivo (19)F MR spectral features (line width and chemical shift) were recorded as a function of time after injection, and the results indicate that the fluorine atoms are indeed sensitive to changes in the local environment while still providing a detectable MR signal. Ex vivo spectra were collected and established the visibility of the (19)F signal under conditions of maximum hypoxia. Late time point (>6 h) tumor tissue concentrations, as obtained from (19)F MRS, suggest that TF-MISO is reduced and retained in hypoxic tumor. The feasibility of obtaining TF-MISO tumor distribution maps in a reasonable time frame was established. CONCLUSIONS: Based on the results presented herein, it is suggested that TF-MISO has the potential to be a valid magnetic resonance hypoxia imaging reporter for both preclinical hypoxia studies and hypoxia-directed clinical therapy.     

Gene expression profiles in primary pancreatic tumors and metastatic lesions of Ela-<Emphasis Type="Italic">c-myc</Emphasis> transgenic mice

Background  

Pancreatic carcinoma usually is a fatal disease with no cure, mainly due to its invasion and metastasis prior to diagnosis. We analyzed the gene expression profiles of paired primary pancreatic tumors and metastatic lesions from Ela-c-myc transgenic mice in order to identify genes that may be involved in the pancreatic cancer progression. Differentially expressed selected genes were verified by semi-quantitative and quantitative RT-PCR. To further evaluate the relevance of some of the selected differentially expressed genes, we investigated their expression pattern in human pancreatic cancer cell lines with high and low metastatic potentials.     

Childhood neurocysticerosis in South India

A total of 21 cases of childhood neurocysticerosis seen over five years (1985–89) at JIPMER hospital Pondicherry, are reported. Nine of these patients were males and twelve females. Their age ranged between 5 to 15 years. The presenting features were convulsive seizures (14), features of raised intracranial pressure (6) and meningoencephalitis syndrome (1). Diagnosis of neurocysticercosis was based on positive CSF serological tests (11), CT morphology (11), brain biopsy (1) and autopsy (1). Praziquantel therapy was given in 4 cases, 3 of them showed remarkable improvement in neurological status and one died of acute reaction.     

Contact lens wear alters the production of certain inflammatory mediators in tears

Contact lens wear has been associated with an increased risk of corneal infection and/or inflammation. We studied the hypothesis that contact lens wear alters the number of polymorphonuclear leukocytes (PMNs) on the cornea during sleep and the levels of inflammatory mediators in the tear film. Three groups of subjects were analysed: a non-contact lens wearing group (NCLW), non-adapted (neophyte) contact lens wearers (NACLW) who wore lenses during sleep for the first time in this study and adapted contact lens wearers (ACLW) who normally wore lenses on a daily wear schedule. Ocular PMNs were collected by a non-contact irrigation technique and their numbers counted after staining. Tears were collected from each group and analysed using ELISAs for the presence of the PMN chemoattractants IL-8 and LTB(4)and the cytokines IL-1beta, IL-6 and GM-CSF. Corneal irrigation data demonstrated significantly higher numbers of PMNs from NACLW (P<0.05) compared to the other groups. ACLW showed significantly fewer PMNs (P =0.03) compared to NCLW group. The NACLW group had significantly lower concentrations (P<0. 05) of IL-8, LTB(4)and IL-6 in their tears after 8 hr of sleep compared to the other groups. The ACLW group had significantly (P<0. 05) higher levels of IL-8 at most time points compared to the other two groups. The levels of the chemoattractants IL-8 and LTB(4)in tears were inversely related to the numbers of PMNs from the corneal surface and the chemotaxis of PMNs in vitro. During one night sleep in contact lenses the numbers of PMNs and the concentration of certain inflammatory mediators are significantly altered compared to no lens wear. However, this alteration changes from NACLW to ACLW. This may have effects on the ability of the eye to defend itself during contact lens wear.     

The differential regulation of nitric oxide by Herpes simplex virus-1 and -2 in a corneal epithelial cell line

Herpes simplex keratitis s a significant cause of blindness worldwide. Nitric oxide (NO) has been shown to play a role in non-specific defence mechanisms and cell signalling in bacterial and parasitic infections. We investigated if Herpes simplex virus (HSV) isolated from keratitis could induce NO production. Human corneal epithelial cells were infected with high (multiplicity of infection; MOI 0.4) and low (MOI 0.04) HSV-1 and HSV-2 concentrations. Culture supernatants were collected at 1 h, 4 h, 8 h, 12 h and 24 h postchallenge. Samples were prepared by removal of proteins by ultrafiltration. Production of NO was measured using nitrite and nitrate assays. Herpes simplex virus-1 downregulated the production of NO, while HSV-2 upregulated NO production. Downregulation of NO could be a survival strategy against the cytotoxic action of NO, to eliminate infected cells. Upregulation of NO production may be associated with the presence of glycoproteins on the viral coat, which have been shown to induce NO in other disease conditions. Further studies are required to confirm the role of NO in viral keratitis.