Identification of Culex pipiens Linnaeus (Diptera: Culicidae) immunogens recognized by host humoral immunity and their impact on survival and fecundity.

Insecticide use continues to be the primary control strategy to reduce insect vector populations. Concerns about insecticide resistance in target organisms, environmental degradation, and possible deleterious impact on human health have led researchers to seek a variety of alternative control strategies. We tested a relatively new method for controlling mosquitoes using host immune response. New Zealand White (NZW) rabbits (Oryctolagus cuniculus) were immunized with salivary gland (SGE), midgut (MGE), or ovary (OVE) extracts from female Culex pipiens L. Immunized rabbits were then exposed to unfed adult mosquitoes which were subsequently observed for changes in survival, fecundity, and hatch success. Parents that fed upon MGE- (P<0.001), SGE- (P<0.018) and OVE- (P<0.018) immunized rabbits experienced significantly higher mortality within 48 hours than parents fed on control rabbits. Midgut extract elicited the strongest effects upon survival (P<0.001), oviposition activity (P<0.001), and hatch success (P<0.001) in the parent generation. Survival (P<0.018), oviposition activity (P<0.001), and hatch success (P<0.001) were likewise strongly reduced in parents fed on SGE-immunized rabbits. Ovary extract-fed parents experienced less pronounced, but significant reductions, in survival (P<0.018) and hatch success (P<0.034). Surviving progeny were most strongly impacted by feeding upon MGE-immunized rabbits. Our study suggests that manipulating host immune response may be a suitable technique for reducing Cx. pipiens mosquito survival and fecundity, and subsequently the potential risk of disease transmission by this species.

Nuclear DNA, serum sialic acid and measured depth in malignant melanoma for predicting disease recurrence and survival.

In a previous multivariate analysis of 151 malignant melanoma patients we identified measured depth of primary lesion (Breslow) and serum N-acetyl-neuraminic acid (NANA) concentration as significant independent predictors of recurrence. Our present study examines the contribution of flow cytometric DNA analysis to prediction of recurrence and survival. Fixed, paraffin-embedded specimens of primary lesions were evaluated from 63 of the previously studied patients. These were prepared for DNA analysis. Of the 28 primaries identified as aneuploid 17 later recurred, while this was true for only 9 of the 35 diploid tumors. On multivariate analysis measured depth was again the most significant predictor of recurrence (p less than 0.001). Additional independent predictors were DNA ploidy (p = 0.02) and NANA (p = 0.05). For survival the independent predictors were measured depth (p = 0.003) and NANA (p = 0.05). Measured depth, DNA ploidy and NANA can be used to construct a model predicting the recurrence risk for stage-I melanoma.

Survival, response and immune effects in a prospectively randomized study of dose strategy for alpha-N1 interferon.

Several tumour sites have now demonstrated objective responses to alpha interferons in a diversity of doses and schedules. Since effectiveness should be enhanced with the identification of an optimal dose strategy, we undertook a prospectively randomized study to compare an intermittent high dose escalating strategy (HDS) vs. a fixed low dose treatment in relation to clinical outcome and laboratory correlates of immune function. HDS patients received interferon alpha-N1 (lymphoblastoid interferon) 5M units m-2 by continuous i.v. infusion over 24 h, escalating by 5 M units m-2 day-1 as tolerated over 10 days, and repeated every 28 days. The low dose strategy (LDS) consisted of a fixed dose of 2 M units m-2 by intramuscular injection daily for 28 days, then daily for 7 days every other week. There were 53 evaluable patients. In keeping with earlier preliminary results there was evidence of improved immune function for HDS patients. They demonstrated a significant increase in the number of CD2+ (sheep red blood cell binding) cells and CD4+ (helper-inducer/suppressor-inducer) cells along with enhanced activity of natural killer cell, and mixed leukocyte culture activity. In addition to improved immune function, HDS patients survived longer than LDS (P = 0.04). Analysis of survival in relation to response suggested that monitoring of minor responses may be of interest for biological agents such as interferon.

Hematologic and immunologic changes in hairy cell leukemia patients treated with alpha interferon.

We prospectively evaluated hematologic and immunologic changes in fourteen hairy cell leukemia patients treated with alpha interferon. Prompt disappearance of circulating hairy cells, and recovery of peripheral blood counts was observed in all patients whereas only four patients had complete disappearance of hairy cell infiltrates from their bone marrow. Immunologic changes included a statistically significant increase of NK cell activity in the whole group and a slight decrease in circulating T cells with a strong trend towards an increase in the T4/T8 lymphocyte ratio (in eight of fourteen patients). Serial hemopoietic progenitor cell culture studies from peripheral blood (thirteen patients) and bone marrow (two patients) showed no correlation between hematologic recovery data and cell culture data.

Study of equine histoplasmosis farciminosi and characterization of Histoplasma farciminosum.

A detailed clinical and mycological study of horse infections with Histoplasma farciminosum was conducted for the first time in the Middle East. The disease seems to prevail in endemic form in the region. In all of the cases studied the infection involved only the cutaneous lymphatics and skin tissue with extension to the regional draining lymph glands. The disease seems to impose serious economic impact in the infected areas. Full description and thorough characterization of both the mycelial form and the yeast phase of the causative fungus were made.

Effect of lymphoblastoid interferon on lymphocyte subsets in cancer patients.

The effect of interferon dose on lymphocyte subsets is unclear for humans, especially with prolonged intermittent administration. Enumeration of T4 and T8 cells and natural killer (NK) cell activity against K562 cells were examined as part of our ongoing randomized clinical study comparing low- and high-dose treatment strategies. Fifty-four patients have been entered into study, of which 46 are now evaluable. High-dose patients showed no significant changes during actual interferon infusion. However, over the entire period on study, there was a significant increase in NK cell activity (p = 0.001), a concurrent decrease in T8 (p = 0.004), and an increase in T4/T8 (p = 0.02). By contrast, for low-dose patients there was a trend of increasing NK activity during interferon administration, but no change during the total time on study, with a concurrent trend of decreasing T4/T8 and a significant increase in T8 (p = 0.01). Although there is as yet no significant response difference between high- and low-dose treatments, a favourable response was associated with an overall increase in NK activity (p = 0.005), a decrease in T8 (p = 0.02), and an increase in T4/T8 (p = 0.03). In a preliminary study of immune complexes in selected patients, an inverse relationship between NK cell activity and immune complex concentration was suggested. This was supported by in vitro addition of autologous immune complex-containing sera during NK cell assay.

Relationship of total serum sialic acid to sialylglycoprotein acute-phase reactants in malignant melanoma.

Reported elevations of total serum sialic acid may be a result of shed tumour-related membrane sialyglycoprotein and/or concurrent elevation of non-specific, acute-phase reactant sialoglycoprotein. To clarify further the specificity and sensitivity of serum sialic acid monitoring, analyses of sialic acid by the thiobarbituric acid method and acute-phase reactants by radial immunodiffusion were made using the same malignant melanoma patients' sera. Preliminary studies of IgG, IgA, IgM, ceruloplasmin and C-reactive protein suggested that these would not be valuable monitors of tumour burden. Single serum samples from 59 melanoma patients and age- and sex-matched controls were further examined for sialic acid, alpha 1-acid glycoprotein, alpha 1-antitrypsin, haptoglobin, and alpha 2-macroglobulin. Patients were grouped according to tumour burden. In pairwise statistical tests, differences between groups tended to be greater for sialic acid than for acute-phase reactants. On discriminant analysis , sialic acid was clearly the most significant single discriminator between groups, with an F statistic of P < 0.00005. Although alpha 1-acid glycoprotein was quite strongly correlated with sialic acid, it was not such a good discriminator and did not add significantly to the predictive power of sialic acid alone.

Toxoplasmosis in Greater Victoria.

Titres of antibody to Toxoplasma gondii were determined in 596 inhabitants of Greater Victoria who were either patients at two hospitals or healthy volunteers. The survey included 404 women of childbearing age, 305 of whom had just given birth. The proportion of persons with antibody to T. gondii at a titre of 1:8 or greater as determined by a methylene blue dye test was 28%. Titration of IgM antibody specific to T. gondii by the indirect fluorescent antibody test, performed in the serum samples with a titre of 1:8 or greater by the dye test, indicated that 3% of the 596 patients had recently acquired infection with T. gondii. The proportion of women with antibody to T. gondii among those who had just given birth was 25%, but the proportion among women aged 31 to 35 years who had just given birth was 37%.

Template method for the fluorescent-antibody technique.

An easily constructed and inexpensive template has been developed, which enables the fluorescent-antibody technique to be applied to serial dilutions and allows 18 assays on a single microscope slide.

Serological diagnosis of congenital toxoplasmosis.

A comparison of the indirect haemagglutination test (IHAT) with the dye test (DT) in 23 infants with congenital toxoplasmosis showed that in the early part of the first year of life the IHAT titres were nearly all lower than the DT titres. In six cases the IHAT was negative or the titre was so low that the cases could have been missed in routine screening. Later in the first year the IHAT titres became higher than the DT and remained so. The infants belonging to mothers with a high IHAT and therefore assumed to have become infected early in pregnancy had severe infections which included all the cases of hydrocephalus. Infants of mothers with low IHAT titres relative to the DT and therefore thought to have been infected later in pregnancy had generalized, mild or subclinical infection. With some difficulty a suitable commercial conjugated anti-IgM serum was found that gave positive results in immunofluorescent antibody tests for specific IgM antibody with all the infected infants and their mothers throughout the first year and negative results in uninfected infants and their mothers.

The relationship and significance of antibody titres as determined by various serological methods in glandular and ocular toxoplasmosis.

Three types of antibody curve have been demonstrated by testing sera during the course of acquired toxoplasmosis by six different techniques. These three types are due to cell-wall antibody, (demonstrated by four of the techniques), to antibody to soluble antigen, and to IgM antibody to the cell wall. These findings have been supported by absorption experiments. A scheme is presented for testing single sera by two or three different tests to indicate the stage and duration of the infection.