Neutralization of Mitochondrial Superoxide by Superoxide Dismutase 2 Promotes Bacterial Clearance and Regulates Phagocyte Numbers in Zebrafish

Mitochondria are known primarily as the location of the electron transport chain and energy production in cells. More recently, mitochondria have been shown to be signaling centers for apoptosis and inflammation. Reactive oxygen species (ROS) generated as by-products of the electron transport chain within mitochondria significantly impact cellular signaling pathways. Because of the toxic nature of ROS, mitochondria possess an antioxidant enzyme, superoxide dismutase 2 (SOD2), to neutralize ROS. If mitochondrial antioxidant enzymes are overwhelmed during severe infections, mitochondrial dysfunction can occur and lead to multiorgan failure or death. Pseudomonas aeruginosa is an opportunistic pathogen that can infect immunocompromised patients. Infochemicals and exotoxins associated with P. aeruginosa are capable of causing mitochondrial dysfunction. In this work, we describe the roles of SOD2 and mitochondrial ROS regulation in the zebrafish innate immune response to P. aeruginosa infection. sod2 is upregulated in mammalian macrophages and neutrophils in response to lipopolysaccharide in vitro, and sod2 knockdown in zebrafish results in an increased bacterial burden. Further investigation revealed that phagocyte numbers are compromised in Sod2-deficient zebrafish. Addition of the mitochondrion-targeted ROS-scavenging chemical MitoTEMPO rescues neutrophil numbers and reduces the bacterial burden in Sod2-deficient zebrafish. Our work highlights the importance of mitochondrial ROS regulation by SOD2 in the context of innate immunity and supports the use of mitochondrion-targeted ROS scavengers as potential adjuvant therapies during severe infections.     

A sandwich ELISA for properdin in clinical specimens

We have developed a symmetrical sandwich ELISA for measuring human properdin (P) in serum by using the globulin fraction from a commercial antiserum as the capture antibody adsorbed on the plastic. The detecting reagent was a glutaraldehyde conjugate of this Ig fraction with alkaline phosphatase. Two types of inhibition were observed in this study. First, inhibition was observed when greater than 2.5 micrograms/ml of the globulin fraction was used to coat the plates. A second type of inhibition was observed for serum dilutions less than 1/400; it was independent of the concentration of capture Ab and did not occur when purified P was assayed. The data generated with this assay could be fitted in log-log mode by a quadratic equation. The coefficient of the linear term in this equation was found to be the same for serum and purified P, within the limits of experimental error. The results for different samples run on the same plate were expressed in terms of the relative concentration of each sample required to produce an OD405 = 0.2. A sample of pooled normal human serum was run on each plate as a reference; it was assigned a titer of 100 ELISA units/ml (EU/ml). The titers of the unknown samples were expressed in terms of EU/ml by reference to this standard. For purified P, the assay could readily detect 10 ng/ml. By comparing purified P with our reference serum pool, we found that 1 EU equals 0.57 microgram. Day-to-day variation for a group of nine normal sera showed a mean difference of -0.85 EU/ml, SD 5.85 EU/ml. The mean titer for these normal sera was 78.9 EU/ml, SD 15.7 EU/ml. In three recovery experiments in which purified P was mixed with pooled normal serum, the recoveries ranged from 96 to 117%. We conclude that the sandwich ELISA constitutes an adequate immunochemical assay for human P in serum specimens.     

Spontaneous and alloantigen-induced cytotoxicity by human T-lymphocyte subpopulations

Freshly isolated human T lymphocytes were separated into two subpopulations on the basis of their ability to form E rosettes after treatment with the phosphodiesterase inhibitor, theophylline. T cells that retained the ability to form E rosettes (T-res cells) and those that failed to form E rosettes (T-sens cells) were assayed for natural killer (NK) cell activity against 51Cr-labeled K562 tumor cells and for the ability to proliferate and kill allogeneic cells in mixed-lymphocyte culture (MLC). T-sens cells were highly enriched for NK activity. In contrast, T-res cells exhibited much less activity than either T-sens or unseparated T cells (T-sens greater than unseparated T cells approximately equal to unseparated PBL approximately equal to non-T cells greater than T-res cells). T-sens cells were poorly responsive to allogeneic cells in proliferation assays and demonstrated greater levels of cytotoxicity against allogeneic cells than T-res cells. T cells stimulated with allogeneic lymphocytes for 7 days were cytotoxic for K562 targets while comparably stimulated non-T cells and T cells cultured with medium were not cytotoxic. Cold target inhibition experiments suggested that within the T-sens subset there are overlapping populations which mediate cytotoxicity against K562 and allogeneic cells. These studies demonstrate that freshly isolated human T cells are composed of heterogeneous populations which differ in their ability to mediate NK and to generate cytotoxic T lymphocytes in culture.     

Testing the Habituation-Based Model of Exposures for Child and Adolescent Anxiety

Exposure has been identified as key to effective treatment of youth anxiety. However, the precise theoretical mechanisms of exposure are a matter of debate. Emotional processing theory emphasizes the need for fear activation during exposure and its habituation both within and across exposures. Despite the popularity of the theory to explain exposure, it has not been tested with anxious youth. To determine whether emotional processing theory parameters predict anxiety severity, coping abilities, and global functioning after cognitive-behavioral treatment. The present study examined 72 youth (M_age = 10.50 years; 45% female; 87.5% non-Hispanic Caucasian) diagnosed with an anxiety disorder and who received family or individual CBT. Three exposure habituation variables—initial fear activation (peak anxiety), within-session habituation, and between-session habituation—were assessed using Subjective Units of Distress and examined as predictors of outcome at posttreatment and at 1-year follow-up. Outcomes were measured using the Coping Questionnaire, Multidimensional Anxiety Scale for Children, Revised Children’s Manifest Anxiety Scale, Children’s Global Assessment Scale, and clinician severity ratings on the Anxiety Disorder Interview Schedule. Emotional processing theory variables did not predict any anxiety outcomes at posttreatment or follow-up with one exception: Initial fear activation predicted less anxiety at follow-up among youth without GAD. In addition, within- and between-session habituation were not associated with one another. Between-session habituation was not associated with initial fear activation. These findings suggest a limited role of habituation within cognitive-behavioral therapy for anxiety in youth. An alternative to emotional processing theory, inhibitory learning theory, is discussed.     

Towards a Neurotransmitter-Based Retinal Prosthesis Using an Inkjet Print-head

Electronic chips that provide a patterned stimulus to cells in the retina may provide a viable treatment for age-related macular degeneration. A surrogate MEMS device, in the form of a print-head from a desktop printer, has been used to eject a pattern of neurotransmitters (bradykinin) onto living rat pheochromocytoma (PC12) cells. Fluorescent calcium imaging was used to measure the patterned stimulation of individual cells. The chemical stimulation of cells by directed microfluidic delivery may have applications in retinal prosthetic devices, and in other prosthetic implants in the nervous system.     

National contaminant biomonitoring program: Residues of organochlorine chemicals in U.S. Freshwater Fish, 1976–1984

The U.S. Fish and Wildlife Service periodically determines concentrations of organochlorine chemicals in freshwater fish collected from a nationwide network of stations as part of the National Contaminant Biomonitoring Program (NCBP, formerly a part of the National Pesticide Monitoring Program). From late 1984 to early 1985, a total of 321 composite fish samples were collected from 112 stations and analyzed for organochlorine chemical residues. The mean concentrations of total DDT did not change from 1980–81 to 1984, following a period of steady decline through the 1970's; however, the mean concentrations ofp,p-DDT declined significantly. The most persistent DDT homolog (p,p-DDE) was detected at 98% of the stations sampled in 1984, and constituted 73% of total DDT residues, up from 70% in 1974–79. Collectively, these findings indicate a low rate of influx and continued weathering of DDT in the environment. Residues of polychlorinated biphenyls (PCBs) also remained widespread, but a significant downward trend in total PCBs was evident, and early eluting PCB components were present at fewer stations than in the past. Mean concentrations of dieldrin have not changed since 1978–79; concentrations remained highest in Hawaii and in the Great Lakes. Toxaphene concentrations declined from 1980–81 to 1984, especially in the Great Lakes, and the incidence of toxaphene declined from 88% of the stations sampled in 1980–81 to 69% in 1984. Mean chordane concentrations did not change from 1980–81 to 1984, following a period of decline; however,trans-nonachlor replacedcis-chlordane as the most abundant component, suggesting a lower influx of chlordane to the aquatic environment. Residues of other organochlorines—mirex, pentachloroanisole (PCA), benzene hexachloride (BHC) isomers, endrin, heptachlor, hexachlorobenzene (HCB), and Dacthal^® (DCPA)—were either found at relatively few (<25%) of the stations sampled in 1984 or were characterized by relatively low concentrations. In general, organochlorine concentrations were lower in 1984 than at any time reported previously.     

Psychometric validation of the revised Functional Assessment of Human Immunodeficiency Virus Infection (FAHI) quality of life instrument

The revised Functional Assessment of Human Immunodeficiency Virus Infection (FAHI) quality of life (QoL) instrument has been updated and expanded to provide more complete and accurate coverage of human immune deficiency virus/ acquired immune deficiency syndrome (HIV/AIDS)-related QoL. Factor analysis and the Rasch measurement model were used to determine a new subscale structure for the FAHI. The content of these subscales, including physical well-being (ten items, = 0.91), function and global well-being (13 items, = 0.86), emotional well-being/living with HIV (10 items, = 0.82), social well-being (eight items, = 0.73), and cognitive functioning (three items; = 0.75), reflect both general illness- and HIV/AIDS-specific QoL concerns: a total QoL score can also be calculated for the FAHI (44 items, =0.91). Psychometric evaluation revealed good internal consistency reliability for the FAHI and its subscales. In addition, construct validity, known groups validity and sensitivity to change were demonstrated by significant associations between the FAHI and additional indicators of functional status, psychological symptoms, stress and illness severity. In summary, the FAHI is a psychometrically sound instrument that captures multiple important dimensions of HIV/AIDS-related QoL. It is brief, easy to administer and score, has been translated into nine languages other than English and is appropriate for use in clinical trials and clinical practice.     

The treatment of difficult proximal femoral fractures with the Russell-Taylor reconstruction nail

The outcome of 30 proximal femoral fractures and pathological lesions in 29 patients treated with the Russell-Taylor reconstruction nail are reported. Four patients had fractures involving both the femoral neck and shaft (segmental). Fifteen patients had extensive comminuted fractures of the proximal femur and ten patients underwent nailing because of pathological fractures (one bilateral). In nineteen operations there were technical difficulties, nail insertion and proximal interlocking being the commonest. In the elderly there was a high post-operative complication rate. Three nails needed to be revised for failure of fixation. On review, all patients under sixty years of age regained full mobility and returned to their pre-fracture level of activities. Patients with per-trochanteric fractures over the age of sixty had less favourable results. No cancer patient returned to their prefracture mobility level. The Russell-Taylor reconstruction nail proved to be useful in the treatment of segmented and, in a lesser degree, pathological fractures. However, the surgical technique is demanding and there is a high incidence of post-operative complications in the patients over the age of sixty.     

The social ecology of syphilis.

Factors affecting the transmission of syphilis can be categorized into those acting at the level of individuals (e.g., number of sex partners) and others at the level of the sociophysical environment (e.g., availability of treatment services for curable infections). In a prior study, we identified several sociophysical factors correlated with the ten-year mean syphilis rate in a regression analysis of United States counties. In the present study we used qualitative methods to investigate additional aspects of some factors in the regression, as well as to identify entirely new factors. Twelve counties with populations less than 100,000 and ten-year mean syphilis rates that were greater or less than expected by the regression model were selected for a three to five day visit. The case study protocol included observations, unstructured interviews with care providers and county residents, and a standardized questionnaire completed by state and local sexually transmitted disease control personnel pertaining to characteristics and practices of the local health department. Comparisons of the field notes and questionnaires revealed patterns of factors of the sociophysical environment that potentially affect county syphilis rates. These included access to the health department STD clinic, race relations, employment opportunities for minorities, interagency coordination, STD outreach activities, the social acceptability of discussing STDs, and intercommunity dynamics. In addition we noted the disproportionate influence of particular individuals on these factors. Some of the factors identified are readily quantifiable and could enhance the predictive power of multivariable models of county syphilis rates. The hypotheses generated by this study may also lead to a better measurement and understanding of potentially important environmental determinants of community syphilis rates, and the development of new or enhanced prevention strategies.