A parameterized model for selecting the optimum file organization in multi-attribute retrieval systems.

Massachusetts Institute of Technology, Alfred P. Sloan School of Management. Thesis. 1974. M.S.MICROFICHE COPY ALSO AVAILABLE IN DEWEY LIBRARY.Bibliography: leaves 135-142.M.S

The role of light signaling on astrocytic morphological plasticity in the adult male rat suprachiasmatic nucleus

The body’s master clock lies at the base of the hypothalamus immediately above the optic chiasm. Because of the intimate connection to the optic chiasm, this hypothalamic nucleus was named the suprachiasmatic nucleus (SCN). Environmental light signaling conveys time of day and seasonal changes to the SCN via the retinohypothalamic tract (RHT). The SCN then relays this information to the brain and the rest of the body through synaptic signaling and indirectly through circadian regulation of hormonal signaling. The SCN is unique in that in the absence of external signaling, circadian rhythms will persist. This is accomplished through a transcription-translation feedback loop consisting of both positive and negative transcription factors. The interactions of the players within this loop create a near 24 hour rhythm. Although research within the SCN has focused primarily on neuronal signaling astrocytes comprise nearly a third of the total number of cells within the nucleus based on stereological analysis. Moreover, the astrocyte cytoskeletal marker, glial fibrillary acidic protein (GFAP), is expressed in much higher levels compared to other local hypothalamic regions containing neuronal fibers. GFAP allows for the rough estimation of the overall astrocyte cell shape and despite a lack of in vivo polymerization dynamics, in vitro GFAP filaments have been shown to be dynamically regulated by phosphorylation by known kinases. Additionally, the synaptic signals encoding light information, glutamate and pituitary adenylate cyclase activating peptide (PACAP), have been shown to bind to receptors that activate kinases responsible for GFAP phosphorylation. Based on this work, we hypothesized that the RHT regulates astrocytic cytoskeletal dynamics within the SCN of the male rat. To show this we established that GFAP immunofluorescence is significantly different between early day and early night within the SCN. We then showed that this observable difference is likely due to a shift in GFAP polymerization state from filaments into soluble monomers. Second, we clearly show that this polymerization shift is regulated by the optic nerve and not a circadian phenomenon. We further establish that long term enucleation decreases the overall GFAP levels relative to other local hypothalamic regions, suggesting that the higher levels of GFAP within the SCN is regulated by the optic nerve. Lastly, in order to establish a model system to study effects RHT signals have on SCN astrocytes we characterized the polymerization state of GFAP within the brain slice. Moreover, we studied the effects of glutamate and PACAP on the brain slice. In conclusion, we have determined that signals from the RHT drive the observed levels of GFAP as well as the polymerization state of the GFAP cytoskeleton in the adult male rat SCN

Air freshener composition containing a fiber pad

This invention is directed to an air freshener composition containing a fiber pad comprising at least one needle-punched, nonwoven, hydrophilic fiber wherein the fiber has a capillary structure and deep grooves or channels along the longitudinal axis of the fiber, a fragrance incorporated into said fiber pad, wherein the fiber pad is enclosed by a container having air passageways to allow for the fragrance to escape into the surrounding environment

The P450 CYP6Z1 confers carbamate/pyrethroid cross-resistance in a major African malaria vector beside a novel carbamate-insensitive N485I acetylcholinesterase-1 mutation

Carbamates are increasingly used for vector control notably in areas with pyrethroid resistance. However, a cross-resistance between these insecticides in major malaria vectors such as Anopheles funestus could severely limit available resistance management options. Unfortunately, the molecular basis of such cross-resistance remains uncharacterized in An. funestus, preventing effective resistance management. Here, using a genome-wide transcription profiling, we revealed that metabolic resistance through up-regulation of cytochrome P450 genes is driving carbamate resistance. The P450s CYP6P9a, CYP6P9b and CYP6Z1 were the most up-regulated detoxification genes in the multiple resistant mosquitoes. However, in silico docking simulations predicted CYP6Z1 to metabolise both pyrethroids and carbamates, whereas CYP6P9a and CYP6P9b were predicted to metabolise only the pyrethroids. Using recombinant enzyme metabolism and inhibition assays we demonstrated that CYP6Z1 metabolizes bendiocarb and pyrethroids, whereas CYP6P9a and CYP6P9b metabolise only the pyrethroids. Other up-regulated gene families in resistant mosquitoes included several cuticular protein genes suggesting a possible reduced penetration resistance mechanism. Investigation of the target-site resistance in acetylcholinesterase 1 (ace-1) gene detected and established the association between the new N485I mutation and bendiocarb resistance (Odds ratio 7.3; P<0.0001). The detection of multiple haplotypes in single mosquitoes after cloning suggested the duplication of ace-1. A TaqMan genotyping of the N485I in nine countries revealed that the mutation is located only in Southern Africa with frequency of 10-15% suggesting its recent occurrence. These findings will help in monitoring the spread and evolution of carbamate resistance and improve the design of effective resistance management strategies to control this malaria vector

Equine or porcine synovial fluid as a novel ex vivo model for the study of bacterial free-floating biofilms that form in human joint infections

Bacterial invasion of synovial joints, as in infectious or septic arthritis, can be difficult to treat in both veterinary and human clinical practice. Biofilms, in the form of free-floating clumps or aggregates, are involved with the pathogenesis of infectious arthritis and periprosthetic joint infection (PJI). Infection of a joint containing an orthopedic implant can additionally complicate these infections due to the presence of adherent biofilms. Because of these biofilm phenotypes, bacteria within these infected joints show increased antimicrobial tolerance even at high antibiotic concentrations. To date, animal models of PJI or infectious arthritis have been limited to small animals such as rodents or rabbits. Small animal models, however, yield limited quantities of synovial fluid making them impractical for in vitro research. Herein, we describe the use of ex vivo equine and porcine models for the study of synovial fluid induced biofilm aggregate formation and antimicrobial tolerance. We observed Staphylococcus aureus and other bacterial pathogens adapt the same biofilm aggregate phenotype with significant antimicrobial tolerance in both equine and porcine synovial fluid, analogous to human synovial fluid. We also demonstrate that enzymatic dispersal of synovial fluid aggregates restores the activity of antimicrobials. Future studies investigating the interaction of bacterial cell surface proteins with host synovial fluid proteins can be readily carried out in equine or porcine ex vivo models to identify novel drug targets for treatment of prevention of these difficult to treat infectious diseases

Clarence I. Chatto Correspondence

Entries include a lengthy biographical feature article newspaper clipping with the photographic image of Chatto, and a typed letter on The Public Schools of Springfield, Massachusetts Classical High School stationery

Multiple insecticide resistance in the major malaria vector Anopheles funestus in southern Ghana: implications for malaria control

Background Understanding the dynamics of insecticide resistance in African malaria vectors is crucial for successful implementation of resistance management strategies in the continent. This study reports a high and multiple insecticide resistance in Anopheles funestus from southern Ghana which could compromise the Malaria Operational Plan in this country, if not tackled. Adult Anopheles mosquitoes were collected in Obuasi and Adawukwa, in southern Ghana. Plasmodium infection rates, susceptibility to the main insecticides used in public health and the molecular basis of insecticide resistance were established. Results An. funestus (sensu stricto) (s.s.) was the predominant mosquito species found resting inside the houses in Obuasi, while at Adawukwa it was found together with An. coluzzii. Parasite rates were high in An. funestus (s.s.) populations from both localities, with Plasmodium infection rates greater than 12.5 %. Both, An. funestus (s.s.) and An. coluzzii, from the two sites exhibited high resistance to the insecticide from various classes including the pyrethroids, carbamates and DDT, but remained fully susceptible to the organophosphates. A preliminary characterization of the underlying molecular mechanisms of resistance in An. funestus (s.s.) populations from both sites revealed that CYP6P9a, CYP6P9b, CYP6M7 and GSTe2 genes are upregulated, markedly higher in Obuasi (between 3.35 and 1.83 times) than in Adawukwa population. The frequency of L119F-GSTe2 and A296S-RDL resistance markers were also higher in Obuasi (42.5 and 68.95 % higher), compared with An. funestus (s.s.) populations from Adawukwa. These findings suggest that the similar resistance pattern observed in both An. funestus (s.s.) populations are driven by different mechanisms. Conclusions Resistance to multiple insecticides in public health use is present in malaria vectors from Ghana with major resistance genes already operating in the field. This should be taken into consideration in the design of resistance management strategies to avoid operational failure

Investigating molecular basis of lambda-cyhalothrin resistance in an Anopheles funestus population from Senegal.

BACKGROUND Anopheles funestus is one of the major malaria vectors in tropical Africa, notably in Senegal. The highly anthropophilic and endophilic behaviours of this mosquito make it a good target for vector control operations through the use of insecticide treated nets, long-lasting insecticide nets and indoor residual spraying. However, little is known about patterns of resistance to insecticides and the underlying resistance mechanisms in field populations of this vector in Senegal. METHODS Here, we assessed the susceptibility status of An. funestus populations from Gankette Balla, located in northern Senegal and investigated the potential resistance mechanisms. RESULTS WHO bioassays indicated that An. funestus is resistant to lambda-cyhalothrin 0.05 % (74.64 % mortality), DDT 4 % (83.36 % mortality) and deltamethrin 0.05 % (88.53 % mortality). Suspected resistance was observed to permethrin 0.75 % (91.19 % mortality), bendiocarb 0.1 % (94.13 % mortality) and dieldrin 4 % (96.41 % mortality). However, this population is fully susceptible to malathion 5 % (100 % mortality) and fenitrothion 1 % (100 % mortality). The microarray and qRT-PCR analysis indicated that the lambda-cyhalothrin resistance in Gankette Balla is conferred by metabolic resistance mechanisms under the probable control of cytochrome P450 genes among which CYP6M7 is the most overexpressed. The absence of overexpression of the P450 gene, CYP6P9a, indicates that the resistance mechanism in Senegal is different to that observed in southern Africa. CONCLUSIONS This study represents the first report of pyrethroid and DDT resistance in An. funestus from Senegal and shows that resistance to insecticides is not only confined to An. gambiae as previously thought. Therefore, urgent action should be taken to manage the resistance in this species to ensure the continued effectiveness of malaria control

The Cytochrome P450 gene CYP6P12 confers pyrethroid resistance in kdr-free Malaysian populations of the dengue vector Aedes albopictus

Control of Aedes albopictus, major dengue and chikungunya vector, is threatened by growing cases of insecticide resistance. The mechanisms driving this resistance remain poorly characterised. This study investigated the molecular basis of insecticide resistance in Malaysian populations of Ae. albopictus. Microarray-based transcription profiling revealed that metabolic resistance (cytochrome P450 up-regulation) and possibly a reduced penetration mechanism (consistent over-expression of cuticular protein genes) were associated with pyrethroid resistance. CYP6P12 over-expression was strongly associated with pyrethroid resistance whereas CYP6N3 was rather consistently over-expressed across carbamate and DDT resistant populations. Other detoxification genes also up-regulated in permethrin resistant mosquitoes included a glucuronosyltransferase (AAEL014279-RA) and the glutathione-S transferases GSTS1 and GSTT3. Functional analyses further supported that CYP6P12 contributes to pyrethroid resistance in Ae. albopictus as transgenic expression of CYP6P12 in Drosophila was sufficient to confer pyrethroid resistance in these flies. Furthermore, molecular docking simulations predicted CYP6P12 possessing enzymatic activity towards pyrethroids. Patterns of polymorphism suggested early sign of selection acting on CYP6P12 but not on CYP6N3. The major role played by P450 in the absence of kdr mutations suggests that addition of the synergist PBO to pyrethroids could improve the efficacy of this insecticide class and overcome resistance in field populations of Ae. albopictus