Synaptotagmin-2 controls regulated exocytosis but not other secretory responses of mast cells.

Mast cell degranulation is a highly regulated, calcium-dependent process, which is important for the acute release of inflammatory mediators during the course of many pathological conditions. We previously found that Synaptotagmin-2, a calcium sensor in neuronal exocytosis, was expressed in a mast cell line. We postulated that this protein may be involved in the control of mast cell-regulated exocytosis, and we generated Synaptotagmin-2 knock-out mice to test our hypothesis. Mast cells from this mutant animal conferred an abnormally decreased passive cutaneous anaphylaxis reaction on mast cell-deficient mice that correlated with a specific defect in mast cell-regulated exocytosis, leaving constitutive exocytosis and nonexocytic mast cell effector responses intact. This defect was not secondary to abnormalities in the development, maturation, migration, morphology, synthesis, and storage of inflammatory mediators, or intracellular calcium transients of the mast cells. Unlike neurons, the lack of Synaptotagmin-2 in mast cells was not associated with increased spontaneous exocytosis.

PCR-based assay using occult blood detection cards for detection of diarrheagenic Escherichia coli in specimens from U.S. travelers to Mexico with acute diarrhea.

Large field studies of travelers' diarrhea for multiple destinations are limited by the need to perform stool cultures on site in a timely manner. A method for the collection, transport, and storage of fecal specimens that does not require immediate processing and refrigeration and that is stable for months would be advantageous. This study was designed to determine if enterotoxigenic Escherichia coli (ETEC) and enteroaggregative E. coli (EAEC) DNA could be identified from cards that were processed for the evaluation of fecal occult blood. U.S. students traveling to Mexico during 2005 to 2007 were monitored for the occurrence of diarrheal illness. When ill, students provided a stool specimen for culture and occult blood by the standard methods. Cards then were stored at room temperature prior to DNA extraction. Fecal PCR was performed to identify ETEC and EAEC in DNA extracted from stools and from occult blood cards. Significantly more EAEC cases were identified by PCR that was performed on DNA that was extracted from cards (49%) or from frozen feces (40%) than from culture methods that used HEp-2 adherence assays (13%) (P < 0.001). Similarly, more ETEC cases were detected from card DNA (38%) than from fecal DNA (30%) or by culture that was followed by hybridization (10%) (P < 0.001). The sensitivity and specificity of the card test were 75 and 62%, respectively, compared to those for EAEC by culture and were 50 and 63%, respectively, compared to those for ETEC. DNA extracted from fecal cards that was used for the detection of occult blood is of use in identifying diarrheagenic E. coli.

DETERMINANTS OF THE SELECTIVE PHAGOCYTOSIS OF CARCINOGENIC PARTICULATE NICKEL COMPOUNDS

Certain inorganic nickel compounds such as crystalline NiS and Ni(,3)S(,2) are potent inducers of carcinogenesis and in vitro cell transformation, while several closely-related compounds such as amorphous NiS are essentially devoid of genotoxic activity. The phenomenon of selectivity of phagocytosis among such particulate nickel compounds has been hypothesized to account for their widely varying toxicological potency, yet the determinants of this selectivity have not been well characterized. Extracellular medium composition, particle dissolution, and particle surface charge were examined as potential determinants of selective phagocytosis for the carcinogenic crystalline and noncarcinogenic amorphous modifications of NiS. Selectivity and avidity of uptake of crystalline NiS by CHO cells was not dependent upon serum: phagocytosis of crystalline, but not amorphous NiS proceeded readily in a minimal salts/glucose medium at 37(DEGREES)C. The evolution of phagocytosis-inhibiting Ni(II) from the surface of amorphous NiS particles did not demonstrably contribute to the lower uptake of these noncarcinogenic particles despite their somewhat greater dissolution rate than the readily phagocytosed crystalline NiS particles. Significant differences in surface charge were noted between crystalline and amorphous NiS, the former being more negative in charge in distilled water suspension. Exposure of amorphous NiS particles to the vigorously reducing environment of a LiAlH(,4) solution under an inert atmosphere resulted in the particles' acquisition of a more negative surface charge. Amorphous NiS particles thus treated were phagocytosed by CHO cells to an extent similar to that of untreated crystalline NiS particles and likewise were shown to induce morphological transformation of primary Syrian hamster embryo cells with a similar potency. The potentiation of uptake characteristic of LiAlH(,4)-treated amorphous NiS was lost gradually upon storage of particles in ambient oxygenated atmosphere and was lost rapidly by apparent particle surface oxidation in aerated distilled water suspensions aged for up to 7 days. Concomitant with this loss of uptake there occurred a loss of negative surface charge. These results suggest the predominant role of particle surface charge rather than adsorbed serum components or particle dissolution as a determinant of selective phagocytosis among particulate nickel compounds. ^

An ethnographic study of home remedy use for African-American children

Background and significance. The use of herbs and other remedies by adult and elderly African-Americans has been documented. However, little is understood regarding the use of herbs for African-American children. The purpose of this study was to document and describe the historical and present day uses of herbal and other remedies, specifically for the health and illness of African-American children. This information will provide health care providers with a better understanding of their African-American patients. This information may also contribute to the emerging appreciation of indigenous uses of phytotherapeutics. ^ Methods. A focused ethnographic approach was used to describe the cultural context, including the beliefs, values, customs, and behaviors of a particular culture. The use of intensive fieldwork, including participant observation, audiotaped formal interviews, photographs, and specimen collection of plants helped to describe herb use in this population. Information on the growing, harvesting, preparation, and storage of these plant remedies, as well as the amount and dosage of these compounds was collected in a typology. Detailed information was gathered to discern how, when, and under what conditions these remedies were used and their expected results. Further data collection focused on the history of herbal use, and explanations for how and why informants thought the herbs work. ^ Setting and participants. The setting for this study was in East Texas and field work extended over the period of one year. Thirty African-Americans, age 38 to 98, were interviewed for the study. The African-American population in this area has been relatively stable, with roots dating back prior to the reconstruction period, which allowed excellent historical information. Informants were chosen by a nominated sampling technique starting with two key informants knowledgeable about the use of home remedies for children. ^ Findings. The findings of this study suggest that African-American children in East Texas have a long history of receiving herbs and home remedies for health promotion and illness. Data further suggests that there is a strong connection between spirituality and the health beliefs and practices of this community. This spiritual component underlies the accuracy of oral recall for remedies that have been used over many generations and the use of natural folk remedies. A typology of the herbal remedies was developed with folk and Latin name, herb place of origin, known scientific properties, and informant folk usage and dosage information. ^

The contributions of the hippocampal formation, perirhinal cortex and areas TH/TF to object, spatial and contextual recognition memory in primates

Adult monkeys (Macaca mulatta) with lesions of the hippocampal formation, perirhinal cortex, areas TH/TF, as well as controls were tested on tasks of object, spatial and contextual recognition memory. ^ Using a visual paired-comparison (VPC) task, all experimental groups showed a lack of object recognition relative to controls, although this impairment emerged at 10 sec with perirhinal lesions, 30 sec with areas TH/TF lesions and 60 sec with hippocampal lesions. In contrast, only perirhinal lesions impaired performance on delayed nonmatching-to-sample (DNMS), another task of object recognition memory. All groups were tested on DNMS with distraction (dDNMS) to examine whether the use of active cognitive strategies during the delay period could enable good performance on DNMS in spite of impaired recognition memory (revealed by the VPC task). Distractors affected performance of animals with perirhinal lesions at the 10-sec delay (the only delay in which their DNMS performance was above chance). They did not affect performance of animals with areas TH/TF lesions. Hippocampectomized animals were impaired at the 600-sec delay (the only delay at which prevention of active strategies would likely affect their behavior). ^ While lesions of areas TH/TF impaired spatial location memory and object-in-place memory, hippocampal lesions impaired only object-in-place memory. The pattern of results for perirhinal cortex lesions on the different task conditions indicated that this cortical area is not critical for spatial memory. ^ Finally, all three lesions impaired contextual recognition memory processes. The pattern of impairment appeared to result from the formation of only a global representation of the object and background, and suggests that all three areas are recruited for associating information across sources. ^ These results support the view that (1) the perirhinal cortex maintains storage of information about object and the context in which it is learned for a brief period of time, (2) areas TH/TF maintain information about spatial location and form associations between objects and their spatial relationship (a process that likely requires additional time) and (3) the hippocampal formation mediates associations between objects, their spatial relationship and the general context in which these associations are formed (an integrative function that requires additional time). ^

A PCR based assay for the detection of enteric pathogens from Hemoccult(RTM) cards

Background. Large field studies in travelers' diarrhea (TD) in multiple destinations are limited by the need to perform stool cultures on site in a timely manner. A method for the collection, transport and storage of fecal specimens that does not require immediate processing, refrigeration and is stable for months would be advantageous. ^ Objectives. Determine if enteric pathogen bacterial DNA can be identified in cards routinely used for evaluation of fecal occult blood. ^ Methods. U.S. students traveling to Mexico in 2005-07 were followed for occurrence of diarrheal illness. When ill, students provided a stool specimen for culture and occult blood by the standard method. Cards were then stored at room temperature prior to DNA extraction. A multiplex fecal PCR was performed to identify enterotoxigenic Escherichia coli and enteroaggregative E. coli (EAEC) in DNA extracted from stools and occult blood cards. ^ Results. Significantly more EAEC cases were identified by PCR done in DNA extracted from cards (49%) or from frozen feces (40%) than by culture followed by HEp-2 adherence assays (13%). Similarly more ETEC cases were detected in card DNA (38%) than fecal DNA (30%) or culture followed by hybridization (10%). Sensitivity and specificity of the card test was 75% and 62%, respectively, and 50% and 63%, respectively, when compared to EAEC and ETEC culture, respectively, and 53% and 51%, respectively compared to EAEC multiplex fecal PCR and 56% and 70%, respectively, compared to ETEC multiplex fecal PCR. ^ Conclusions. DNA extracted from fecal cards used for detection of occult blood is of use in detecting enteric pathogens. ^