International indoor and outdoor evaluation of Bacillus sphaericus products: complexity of standardizing outdoor protocols

Only one Bacillus sphaericus strain, strain 2362, is currently used commercially to control Culex larval populations. A reliable methodology, easily used, was developed to identify new strains for field application. Larvicidal activities of 3 highly mosquitocidal strains, strains C3-41, Mal, and LB24, previously selected in the laboratory, were compared with that of strain 2362 in tropical and European countries. The following steps were performed: production and titration of acetonic powders from these 4 strains on local Culex species, survey of initial and residual activity under standardized indoor and outdoor conditions, and evaluation of the efficacy of liquid formulations of the 4 strains in natural breeding sites of Culex. In indoor conditions, strain C3-41 showed the highest activity on both Culex pipiens and Culex quinquefasciatus; strain Mal was the least active. The residual activity causing 80% mortality differed from 20 to 90 days according to the strains and the country. Outdoor experiments with powders (0.02-1.6 mg/liter) were performed and the initial toxicities were similar in all cases. Residual activities were very different, from 6 to 95 days posttreatment. Liquid formulations were applied to larval habitats (from 0.1 to 10 g/m2). In tropical countries, larval recolonization in cesspits or ponds occurred after 10-35 days. In Europe, higher doses were needed in polluted water than in clear water (from 3 to 10 liter/ha) for the same control, and the time before 80% residual activity was reached was less than 9-12 days. However, in cesspits, residual activity could be observed for 12 days to 5 mo. A strain 3-5 times more active than the others in bioassays is not significantly detectable from those strains in field trials.

Culicidae (Diptera) in the diet of predatory stages of anurans (Amphibia) in humid biotopes of the Rhine Valley in Germany

A three-year field study was conducted during 1993 to 1995 to determine the importance of mosquitoes in the diet of anurans. The study was aimed to assess the impact of biological mosquito control on the populations of amphibia in the Rhine Valley, Germany. Sampling took place in two areas with stands of different deciduous trees at the western bank of the Rhine (north of Karlsruhe, Germany) from early May to late October. The frequency and species composition of the terrestrial stages of Amphibia was monitored by hand catches and by live pitfall trapping. A total of 2,419 Amphibia were caught in the three years. Of these, 95.8% were anurans, consisting of 77% Ranidae, with 25.5% Rana arvalis, and 4.2% were Urodela, Salamandridae. All anura caught were subjected to "stomach flushing" to yield their stomach contents before they were released again. The stomachs of 2,163 anuran specimens contained an average of 7.7 prey items, of which only 0.16% were Culicidae. In R. arvalis the total diet consisted of 33% Collembola, spiders and beetles; 0.1% of the specimens in the diet were Culicidae. The most common culicid species in the study area, Aedes vexans, was also most often found in the anuran stomachs. However, no correlation existed between the number of mosquitoes and their number as prey of Anura. It is concluded that anurans will not be negatively affected by biological mosquito control in the Rhine Valley. Furthermore, the impact of anurans on Culicidae seems to be negligible.

Dispersal behavior of adult snow melt mosquitoes in the Upper Rhine Valley, Germany

The dispersal behavior of female snow melt mosquitoes was studied in two forests in Rhineland-Palatinate, Germany, from April to August 1993. Both CDC-light-traps and human bait collections were used to collect mosquitoes. Sampling sites were chosen along a west-east and a north-south transect in treated and untreated parts of a forest with a village in its center. Around this settlement, breeding sites within a radius of 1.5 to 2.5 km were treated. It could be shown that this buffer zone is sufficient to prevent a nuisance caused by snow melt mosquitoes in the village. The results lead to the conclusion that snow melt mosquitoes do not regularly migrate over large distances but stay near their breeding sites. In a detailed study of the behavior of Aedes rusticus, it could be observed that these mosquitoes were resting in the interior of the forest during daytime and leaving it with increasing dusk up to 50 m from the forest edge. A comparison of landing rate counts near a row of trees and in the open field showed higher activity near the row of trees indicating visual orientation of the mosquitoes. Although the Ae. rusticus females left the forest regularly, no nuisance occurred in nearby villages. The treatment of breeding sites near settlements appeared to be sufficient to prevent a nuisance caused by the snow melt mosquitoes.

Epidemiologic investigation of serum levels of the soluble forms of CD25, CD54 and CD58, and T cell responsiveness after stimulation via the CD2-dependent pathway in a random sample of the general population

A sero-epidemiologic correlation study on immune parameters which would correlate with the frequency of common colds (FCC) had been conducted in 1992. There, an inverse relationship between circulating adhesion molecules CD54 and CD58 and FCC was found. Eighteen months later we performed an analogous assessment in order to verify the previous findings and to carry out additional experiments including in vitro proliferative responses of T cells and their production of various cytokines (IFN-gamma, IL-2, IL-6 and IL-10). The additional examinations showed that individuals with frequent common colds exert a higher T cell proliferation and higher production of cytokines than persons which experience never or few common cold infections. These findings could be confirmed statistically. Taken together, the results suggest consistently in individuals with frequent common colds an association with low serum levels of the immunosuppressive soluble adhesion molecules sCD54 and sCD58, high proliferation of unstimulated and stimulated T cells and secretion of higher concentrations of cytokines (IFN-gamma, IL-2, IL-6 and IL-10) into the cell culture supernatants.

Community based dengue control in Columbia: people's knowledge and practice and the potential contribution of the biological larvicide Bti (Bacillus thuringiensis israelensis)

A study on dengue control was undertaken in a poor urban area in Cúcuta, Colombia. The first objective was to describe people's knowledge, attitudes and practices regarding dengue fever, the transmission of the disease and possible preventive measures. The second objective was to analyse the infestation of the community with Aedes aegypti larvae, and the third objective to test the efficacy of Bti (Bacillus thuringiensis israelensis) with respect to the level and duration of reduction of Ae. aegypti larvae in water tanks. It was found that people had a very fragmentary knowledge about dengue and about the necessary protective measures which did not lead them to any action. The infestation of water containers, particularly the larger tanks, was very high (house index = 61; Breteau index = 96). The application of Bti in water tanks led to satisfactory results: For one month and longer, the water tanks treated with Bti were free of mosquito larvae. The effect was reduced by a lower dose, washing the tanks and a less potent formulation. People's acceptance of Bti was higher than that of temephos. Further studies are necessary to confirm the utility of Bti in dengue control.

Congenital nephropathies and uropathies

Although congenital nephropathies and uropathies only represent a fraction of possible genitourinary diseases detected during childhood, they have serious and sometimes avoidable morbidity and mortality. Advances in genetic, molecular, and cellular biology research continue to better define embryologic insults to normal organogenesis and offer the promise that many of these conditions might be avoided in the future. For now, awareness of these entities and their varied presentations and manifestations is crucial so that prompt evaluation and aggressive multidisciplinary management assures the affected child optimal growth and development.

Comparison of carbon dioxide, octenol and a host-odour as mosquito attractants in the Upper Rhine Valley, Germany

Field studies were conducted in the Upper Rhine Valley to determine the responses of mosquitoes to CDC traps baited with either CO2, octenol, light or paired combinations of these. Among eight mosquito species caught, the attractant effect on trap catches was studied in the four most abundant: Aedes vexans, Ae.rossicus, Ae.cinereus and Culex pipiens. Traps baited only with light or octenol caught few mosquitoes, whereas many were caught by traps baited with CO2 alone or in combination with either of the other candidate attractants. CO2 baited traps, with or without light, caught the most Aedes. The combination of CO2 and octenol attracted most Cx pipiens, but this apparent synergy was not significant. Using a caged hamster compared to CO2 as bait in a CDC light-trap with only intermittent fan suction, the hamster attracted less mosquitoes than CO2 emitted at a rate of 225 g/h on days 1 and 2, whereas on days 3 and 4 the smell from the hamster's cage became significantly more attractive than this rate of CO2 for all species of mosquitoes.

The potential for malaria control with the biological larvicide Bacillus thuringiensis israelensis (Bti) in Peru and Ecuador

A study on the efficacy of Bti spraying in mosquito breeding places was undertaken in the Pacific coast of Peru and Ecuador and in the Amazon area of Peru. It was shown that Bti is a powerful larvicide for Anopheles larvae, although it sinks quickly, whereas Anopheles larvae feed at the water surface. The duration of its effect was less than 7 days with the exception of the Amazon area of Peru, where it was approximately 10 days. In two study areas, Bti was sprayed weekly over periods of 10 and 7 weeks, respectively, and the adult mosquito densities were monitored. The Anopheles adult density (bites per person per hour on human baits) was reduced by an average of 70% in one area and by up to 50% in the other. This means that Bti spraying can potentially be an important component of a modified malaria control strategy.

Role of larval cadavers in recycling processes of Bacillus sphaericus

The influence of larval cadavers of Culex pipiens on recycling processes of Bacillus sphaericus was investigated by bioassays and spore counts in the laboratory. Studies conducted with 3 different B. sphaericus concentrations (0.005, 0.01, 0.05 mg B. sphaericus/liter) indicated that the presence of cadavers in the water contributed to the maintenance of toxic levels of B. sphaericus. Larval cadavers seem to contain all the nutrients necessary both for vegetative multiplication and for toxin synthesis associated with the sporulation process. Bioassays of B. sphaericus revealed that the mortality of Culex pipiens remained on a high level over a period of 26 days when larval cadavers were added every second day to the test vessels. This result was supported by a sharp increase in spore density when cadavers were added at the same interval. The test series showed B. sphaericus recycles in intact cadavers of Culex pipiens, whereas this phenomenon could not be observed when crushed cadavers were used in the trials. Therefore, our results demonstrated that for successful recycling processes it seems of crucial importance that infected cadavers remain intact at least for a certain time and also that the dosage of the applied B. sphaericus plays a major role in recycling processes whereas larval density is only of minor importance to these processes.

Characterisation of the Sek-1 receptor tyrosine kinase

We present an initial characterisation of the mouse Sek-1 protein, a member of the Eph subfamily of putative receptor tyrosine kinases, which has been proposed to play a role in the segmentation of both the hindbrain and the mesoderm. Antibodies raised against the protein have been used to confirm the early embryonic expression pattern previously established by mRNA in situ hybridisation. These antibodies, together with the expression of the Sek-1 gene in a baculovirus system, were instrumental in demonstrating that the protein carries a tyrosine kinase activity and that it is presented at the cell surface with its N-terminal (putative ligand-binding) domain outside of the cell. Therefore, as expected from its amino acid sequence, Sek-1 conforms to the general model of receptor-type tyrosine kinases.

Effects of mellow and frenetic music and stimulating and relaxing scents on walking by seniors

Previous research has yielded an inconclusive picture of the effects of music and scent on walking. Few laboratory studies have detected a beneficial effect of music; olfactory research has shown performance is positively affected for repetitive tasks but not yet on walking. The influence of these two types of stimuli in efficiency of exercise among seniors was assessed by measuring distance walked on an indoor course. Using a 3 x 3 factorial design [mellow music in 4:4 time, frenetic music in 2:8 time, and white noise by stimulating, relaxing, and control scent conditions], each of 20 volunteers from a senior center received nine randomized, 90-sec. exercise trials. Walking distance was reduced by mellow music but unaffected by stimulating music; there was no effect of scent.

Dependence of CO2-baited suction trap captures on temperature variations

In order to provide better standardized CO2-baited trap samples, the relationship between sample size and evening temperatures was studied. Adult mosquitoes were collected for 3 h centered on sunset by an automatic interval suction trap baited with CO2 in the Upper Rhine Valley, Germany. Aedes vexans females were most abundant, and their blood-seeking activity showed a significant correlation with the evening's average temperature (r = 0.76, P < or = 0.05). A higher degree of correlation was obtained when the number of specimens caught was related to temperature indices (r = 0.93-0.98, P < or = 0.01). A regression equation indicates the lower temperature threshold for Aedes vexans was between 9 and 10 degrees C. For each degree of increase in the average temperature index, it was estimated that a 5.5% greater number of mosquitoes would be trapped. An upper temperature threshold for this species was not observed at average temperatures < or = 23 degrees C. A relationship between catches of Aedes rossicus and Aedes cinereus and temperatures recorded at the site during the study was not found.

Protocol for the introduction of new Bacillus thuringiensis Israelensis products into the routine mosquito control program in Germany

The efficacy of new and frequently used formulations of Bacillus thuringiensis israelensis (B.t.i.) has been evaluated in the laboratory and in the field conditions under which they will be used in Germany. The principles governing the successful introduction of new formulations of microbial control agents into routine programs have been highlighted. The potency of the formulations in use (Teknar, Bactimos, and Vectobac) and their efficacy against the indigenous mosquito species Aedes vexans, Aedes cantans, and Culex pipiens have been assessed to determine the minimum effective dosage in the laboratory and the optimum effective dosage in small field trials. These results should ensure the proper selection of the most appropriate formulation and dosage for the particular climatic and ecological conditions.

Mellow and frenetic antecedent music during athletic performance of children, adults, and seniors

Previous research has yielded a contradictory picture of the effects of music on athletic performance. While athletes frequently report using music while training or during or before an event, laboratory studies have generally not detected a beneficial effect of music. The influence of music, judged mellow and frenetic, played before exercise was assessed by measuring stationary bicycle mileage. 60 volunteers from three age groups (child, adult, and senior) and with two levels of prior activity (high and low) were subjects. Each participant received three randomized 2-min. exercise trials, each preceded by 1-min. exposure to mellow music, frenetic music, or white noise. Mileage in both music conditions was significantly higher than that during the white-noise control trial except among the senior subjects. No significant differences between frenetic and mellow music were noted.

Detection of adeno-associated virus DNA in human genital tissue and in material from spontaneous abortion

The human helper virus-dependent parvovirus, adeno-associated virus (AAV) has never been associated with disease in humans [Berns et al. (1987): Advances in Virus Research 32:243-306; Siegl et al. (1985): Intervirology 23:61-73]. However, in pregnant mice, infection with AAV induces early abortion [Botquin et al. (1993): Journal of Cancer Research and Clinical Oncology 119:24]. We investigated whether this common human virus may be found in human genital tissue or in curettage material from spontaneous abortion. Using the polymerase chain reaction (PCR) AAV type 2 DNA was amplified in histological sections of 19 of 30 biopsies of the uterine mucosa. In addition, AAV-2 DNA was detected in abortion material during the first trimester of pregnancy (12/30 cases were positive) but not in material of abortion from the second or third trimester (9 cases). Whereas in tissues from the uterus AAV DNA was found only by PCR, large amounts of viral DNA were detectable by Southern blot analysis in abortion material. In situ hybridization revealed DNA of AAV to be present in the villous moiety (trophoblast) of the placenta but not in the embryo or decidua. in the same cells, AAV proteins (including the replication-associated rep proteins) were detected by immunofluorescence analysis. These results suggest (1) that AAV infects the uterine mucosa (possibly persistently) and (2) that it can replicate in trophoblast cells. This might disturb placenta development and may play a role in early miscarriage.(ABSTRACT TRUNCATED AT 250 WORDS)

Several receptor tyrosine kinase genes of the Eph family are segmentally expressed in the developing hindbrain

Pattern formation in the hindbrain involves a segmentation process leading to the formation of metameric units, manifested as successive swellings known as rhombomeres (r). In search for genes involved in cell-cell interactions during hindbrain segmentation, we have screened for protein kinase genes with restricted expression patterns in this region of the CNS. We present the cloning of three novel mouse genes, Sek-2, Sek-3 and Sek-4 (members of the Eph subfamily of putative transmembrane receptor protein tyrosine kinases (RTKs)), the identification of their chromosomal locations, and the analysis of their expression between 7.5 and 10.5 days of development. Before morphological segmentation, Sek-2 is transcribed in a transverse stripe corresponding to prospective r4 and the adjacent mesoderm, suggesting possible roles both in hindbrain segmentation and signalling between neuroepithelium and mesoderm. Sek-3 and Sek-4 have common domains of expression, including r3, r5 and part of the midbrain, as well as specific domains in the diencephalon, telencephalon, spinal cord and in mesodermal and neural crest derivatives. Together with our previous finding that Sek (Sek-1) is expressed in r3 and r5 (Gilardi-Hebenstreit et al., 1992; Nieto et al., 1992), these data indicate that members of the Eph family of RTKs may co-operate in the segmental patterning of the hindbrain.

Fitting epidemiologic follow-up studies with cumulative damage models

The use of an extended version of the cumulative damage model to identify and quantify cancer risk arising from a specified exposure is outlined. For this, a strategy to fit the model to individual data coming from epidemiologic follow-up studies is described. Two statistical problems are addressed: first, the regularity of the model has to be ascertained to allow the application of maximum-likelihood and likelihood-ratio methods for parameter estimation and testing. Second, a statistical test has to be found that permits testing goodness of fit in the setting of parameter estimation with individual data. As an example, these methods are applied to the data of a cohort study on mortality among stainless steel welders in the Federal Republic of Germany. The results show that the model fits the data well and confirms a carcinogenic effect of stainless steel welding among welders. Some distinguishing characteristics of the model, especially its prediction of a potentially decreasing relative risk despite ongoing carcinogenic exposure, are discussed.

Efficacy of Clostridium bifermentans serovar Malaysia on target and nontarget organisms

Clostridium bifermentans serovar malaysia (C.b.m.) is highly toxic to mosquito larvae. In this study, the following aquatic nontarget invertebrates were treated with high C.b.m. concentrations (up to 1,600-fold the toxic concentration for Anopheles stephensi) to study their susceptibility towards the bacterial toxin: Planorbis planorbis (Pulmonata); Asellus aquaticus (Isopoda); Daphnia pulex (Cladocera); Cloeon dipterum (Ephemeroptera); Plea leachi (Heteroptera); and Eristalis sp., Chaoborus crystallinus, Chironomus thummi, and Psychoda alternata (Diptera). In addition, bioassays were performed with mosquito larvae (Aedes aegypti, Anopheles stephensi, and Culex pipiens). Psychoda alternata larvae were very susceptible, with LC50/LC90 values comparable to those of mosquito larvae (about 10(3)-10(5) spores/ml). The tests with Chaoborus crystallinus larvae showed significant mortality rates at high concentrations, but generally not before 4 or 5 days after treatment. The remaining nontarget organisms did not show any susceptibility. The investigation confirms the specificity of C.b.m. to nematocerous Diptera.

Cigarette smoking and lung cancer: a reconsideration of the British doctors' data with cumulative damage models

Cumulative damage models are a macroscopic approach to describe the epidemiologic aspects of carcinogenesis. This approach is based on the conjectures that cancer epidemiology (a) may derive only limited insight into specific biologic processes, and (b) may need no detailed biologic assumptions to obtain sufficient understanding of the relation between environmental exposures and host responses in human populations. The cumulative damage model leads intrinsically to the theoretical interpretation of the epidemiologic aspects of carcinogenesis as a kind of wear-out process. In the present paper, it has been applied to the data of the British physicians' study and is contrasted with some other convenient models. The comparisons show that all considered models fit the data reasonably well. The conclusion is essentially theoretical: because the present model fits the data sufficiently closely, but is based on rather parsimonious biologic assumptions, the specific referral of epidemiologic observations to cellular events, as done by other approaches, might be an overinterpretation of the data.

Cancer mapping: why not use absolute scales?

Cancer atlases frequently use relative scales which rank regional mortality rates relative to the countrywide mean (if relative risks are used) or median (if percentile colour schemes are used). This method has various disadvantages which limit comparability and interpretation. An alternative is absolute scaling which is well-known from geographic atlases: the natural rank order of altitudes is mapped into a colour scheme which is preserved over all maps of an atlas. Applied to cancer atlases this means that the different magnitudes of mortality for different cancer sites and sexes is preserved and leads to the use of different ranges of a relatively wide common colour scheme. This technique is applied to the data of the German Cancer Atlas published in 1984. Its properties are outlined and it is shown that it overcomes many of the unfavourable characteristics of the convenient procedures.

Increased risk of acute myelogenous leukemia (AML) and chronic myelogenous leukemia (CML) in a county of Hesse, Germany

The incidence of acute and chronic myelogenous leukemia has been compared for the two neighbouring regions of Marburg and Giessen in Hesse (Germany). The investigation was based on the incident cases of the years 1983-1989 which have been diagnosed in the hematological departments of the universities of the two regions. The epidemiological evaluation of the data has been carried out in terms of a historical follow-up study, and shows an increased relative risk for the region around Marburg with a particular elevation for one community within this region. Potential determinants are discussed and focus on trinitrotoluene (TNT) and decomposition products which are known to contaminate the soil of this community, in some places severely, due to insufficient removal of remnants of the TNT production in large underground plants during World War II.

Investigations on possible resistance in Aedes vexans field populations after a 10-year application of Bacillus thuringiensis israelensis

In the Upper Rhine Valley (Germany), Bacillus thuringiensis var. israelensis has been widely used against floodwater mosquitoes over an area of approximately 500 km2 for more than 10 years. The susceptibility of larvae of Aedes vexans field populations in 3 untreated (Lake Constance) and 3 treated areas (Upper Rhine Valley) was assessed by means of bioassays with B.t.i. (Bactimos WP, 6,000 AAU/mg), following WHO guidelines. Log-probit analyses and statistical evaluations of the data showed that the LC50 values as well as slopes of bioassays of the larvae deriving from the different areas showed no significant differences. Two populations in the treated area were even more susceptible than populations from the untreated areas. These results have been confirmed by resistance ratios, which were less than one in all tests carried out.

Infusional cyclophosphamide, doxorubicin, and etoposide in human immunodeficiency virus- and human T-cell leukemia virus type I-related non-Hodgkin's lymphoma: a highly active regimen

Fourteen patients with poor-prognosis intermediate- to high-grade non-Hodgkin's lymphoma (NHL) associated with human immunodeficiency virus (HIV) infection (12 patients) or human T-cell leukemia virus type I (HTLV-I) infection (two patients) received cyclophosphamide 750 mg/m2, doxorubicin 50 mg/m2, and etoposide 240 mg/m2 administered as a continuous intravenous (IV) infusion over 4 days (infusional CDE); treatment was repeated every 28 or more days for up to six cycles. All HIV-positive patients had at least one poor prognostic feature, which included either extranodal disease (10 patients), Karnofsky performance status less than 70% (six patients), a CD4 count less than 100/microL (six patients), or a prior history of acquired immunodeficiency syndrome (AIDS; one patient). Both HTLV-I-positive patients had an elevated serum lactate dehydrogenase (LDH) level, a poor prognostic feature in that setting. Complete response (CR) occurred in 10 patients (71%; 95% confidence interval, 48% to 95%) and partial response (PR) occurred in three patients (21%), yielding an overall objective response rate of approximately 93%. The estimated Kaplan-Meier median survival was 17.4 months; seven of 12 HIV-positive patients are alive and disease-free with a median follow-up of 15 months (range, 7 to 24 months). Hospitalization was required after 19% of treatment cycles due to fever associated with granulocytopenia. Documented or suspected opportunistic infection occurred in five patients (36%), bacteremia occurred in three patients (21%), and candidemia occurred in one patient (7%). There was one treatment-related death attributable to disseminated aspergillosis. This pilot study suggests that infusional CDE may be a highly active regimen capable of producing durable remissions in a high proportion of patients with HIV-related NHL. Further study is required to confirm this observation.