Laboratory evaluation of pyriproxifen treated bednets on mosquito fertility and fecundity. A preliminary study

AIM

The study evaluated the effect of pyriproxifen treated bednets on mosquito fertility and fecundity in the laboratory. Pyriproxyfen (insect growth regulator) has been considered as a possible tool for management of pyrethroid resistance in mosquitoes. There are documentations of the effectiveness of pyriproxifen in controlling larval development when applied directly to breeding site. Considerations have been given to the use of pyriproxyfen on bed nets for sterilizing effect on mosquitoes resistant to pyrethroids.

METHOD

Groups of mosquitoes (Anopheles stephensi Beech) were exposed to bednet treated with 2% Pyriproxyfen and untreated netting 24 hrs after blood feeding. After oviposition, egg counts were done for each mosquito in the two groups. Larvae emerging from the laid eggs by each mosquito were counted. Three sets of experiments were successful.

RESULTS

There was no significant difference in number of eggs laid between the two treatment groups (p=0.177). There was statistically significant difference in the number of laid eggs that hatched between the treatment types (p=0.0061). There was also statistically significant difference in the mean number of eggs that hatched between the experiments (p=0.0013). The mean number of eggs retained in the pyriproxyfen group was higher (70.3) than in the control group (41.6). This difference was not statistically significant with the small sample tested (p=0.08).

CONCLUSION

The results suggest that 2% pyriproxyfen on bed nets has no effect on An. stephensi fecundity. Reduced fertility of eggs laid by mosquitoes exposed to pyriproxyfen treated bed nets was observed.

The homeodomain protein Nanog and pluripotency in mouse embryonic stem cells

Intrinsic regulators of the pluripotency of mouse ES (embryonic stem) cells include the homeodomain proteins Oct4 and the recently identified Nanog. When overexpressed, Nanog displays the unique attribute of robustly sustaining ES cell self-renewal in the absence of the otherwise requisite extracellular stimulation by LIF (leukaemia inhibitory factor) and BMP (bone morphogenetic protein). Here, we review our current understanding of the function of Nanog in pluripotent stem cells both in vitro and in vivo.

Earliest evidence of cynodont burrowing

A 251 million year old partial burrow cast containing an articulated skeleton of the mammal-like carnivore Thrinaxodon liorhinus is the oldest evidence for burrowing by a cynodont synapsid. The burrow cast comes from terrestrial flood plain sediments close to the Permian-Triassic boundary in the Karoo of South Africa. Together with those of the later cynodont Trirachodon, the Thrinaxodon burrow cast indicates that burrow-making was broadly distributed in basal synapsids and has a long history in non-mammalian synapsid evolution. A reconstruction of its appendicular skeleton in cross-section indicates that Thrinaxodon was able to adopt a facultatively mammalian stance within its burrow shaft. Burrows of cynodont design are more common in Triassic rocks than previously realized, and suggest that burrowing may represent an adaptive response by cynodonts to the environmental conditions associated with the mass extinction event that punctuated the end of the preceding Permian period. The widespread occurrence of burrowing among extant mammals implies that the ancient synapsid ability to burrow conferred a strong adaptive value in the evolution of Mammalia.

Insecticide-treated plastic tarpaulins for control of malaria vectors in refugee camps

Spraying of canvas tents with residual pyrethroid insecticide is an established method of malaria vector control in tented refugee camps. In recent years, plastic sheeting (polythene tarpaulins) has replaced canvas as the utilitarian shelter material for displaced populations in complex emergencies. Advances in technology enable polythene sheeting to be impregnated with pyrethroid during manufacture. The efficacy of such material against mosquitoes when erected as shelters under typical refugee camp conditions is unknown. Tests were undertaken with free-flying mosquitoes on entomological study platforms in an Afghan refugee camp to compare the insecticidal efficacy of plastic tarpaulin sprayed with deltamethrin on its inner surface (target dose 30 mg/m2), tarpaulin impregnated with deltamethrin (initially > or = 30 mg/m2) during manufacture, and a tent made from the factory impregnated tarpaulin material. Preliminary tests done in the laboratory with Anopheles stephensi Liston (Diptera: Culicidae) showed that 1-min exposure to factory-impregnated tarpaulins would give 100% mortality even after outdoor weathering in a temperate climate for 12 weeks. Outdoor platform tests with the erected materials (baited with human subjects) produced mosquito mortality rates between 86-100% for sprayed or factory-impregnated tarpaulins and tents (average approximately 40 anophelines and approximately 200 culicines/per platform/night), whereas control mortality (with untreated tarpaulin) was no more than 5%. Fewer than 20% of mosquitoes blood-fed on human subjects under either insecticide-treated or non-treated shelters. The tarpaulin shelter was a poor barrier to host-seeking mosquitoes and treatment with insecticide did not reduce the proportion blood-feeding. Even so, the deployment of insecticide-impregnated tarpaulins in refugee camps, if used by the majority of refugees, has the potential to control malaria by killing high proportions of mosquitoes and so reducing the average life expectancy of vectors (greatly reducing vectorial capacity), rather than by directly protecting refugees from mosquito bites. Mass coverage with deltamethrin-sprayed or impregnated tarpaulins or tents has strong potential for preventing malaria in displaced populations affected by conflict.

The introduction of a paediatric anaesthesia information leaflet: an audit of its impact on parental anxiety and satisfaction

BACKGROUND

A paediatric anaesthesia information leaflet was produced to address preoperative parental anxiety and to facilitate informed parental consent.

METHODS

An audit was undertaken to assess the impact of introducing the leaflet. This addressed the information needs and expectations of parents of children undergoing anaesthesia, parental satisfaction with information provision and parental preoperative anxiety.

RESULTS

The audit revealed that parents expect to be provided with information, although not necessarily in written form. However, the majority who received the information leaflet concluded that verbal information alone would not have been sufficient. The information leaflet was found to be accessible, informative and useful and those who received it reported greater satisfaction with information provision than a control group. Many parents perceived that it resulted in lower levels of preoperative anxiety

CONCLUSIONS

A decision was therefore undertaken that routine use of the leaflet would continue on all of the paediatric surgical wards. However, the study also indicated that leaflets should not replace verbal communication with nursing and medical staff, who remain important sources of information.

Using an exercise-based instrument to detect signs of an eating disorder

The study employed an innovative exercise-based instrument to identify individuals at risk for eating disorder (ED). The Exercise Orientation Questionnaire (EOQ), a reliable and valid instrument, was used to compare 80 ED patients, 74 obese patients, 99 elite runners, and 214 controls from a previous study. Runners resembled ED patients in scoring high on total EOQ and exercise intensity but differed in that the athletes scored low on self-loathing (SLSS), a sub-scale of the EOQ. SLSS scores clearly distinguished clinical (ED, obese) from non-clinical groups, while other sub-scales (self-control, weight loss, and identity) did not. The study suggests that it is feasible to detect ED risk through assessment of exercise attitudes and behaviors. The SLSS subscale of the EOQ can differentiate clinical from non-clinical groups and anorexic patients from healthy individuals with body mass index within the anorexic range. The SLSS could provide a theoretical bridge between compulsive athleticism and ED.

An approach to modelling in immunology

Like most other fields in biology, immunology has been revolutionised by the techniques of molecular biology and the resulting explosion in available experimental data. It is argued that efforts to integrate the data to gain insight into how various subsystems in the immune system interact and function require mathematical modelling and computer simulation in close collaboration with experimentalists. This paper illustrates some of the techniques available for modelling immune systems, and highlights the issues that should be borne in mind by anyone starting down the modelling path.

Tumorigenesis in transgenic mice in which the SV40 T antigen is driven by the brain-specific FGF1 promoter

Gene expression can be manipulated by the introduction of a hybrid gene formed by linking a highly tissue-specific regulatory element to a gene whose expression might be expected to alter cellular function. Previously, we have shown that the human FGF1 gene contains four distinct tissue-specific promoters. In an effort to perturb the programming of proliferation and differentiation in a subset of neural cells, we have produced transgenic mice bearing the brain-specific promoter of the human FGF1 gene joined to the SV40 immediate early gene, which encodes the large T antigen. The resulting mice, and offspring from four individual lines, developed brain tumors that originated in the pontine gray, just rostral to the fourth ventricle. Tumors were moderately vascularized, as demonstrated by staining with both hematoxylin and eosin and antibodies to three different endothelial cell markers, but vessels were histologically normal. Scattered tumor foci were present as early as postnatal day 26; and affected animals died between 5 - 8 months of age. In mature animals, tumors lacked terminal differentiation markers for astrocytes (glial fibrillary acidic protein) or neurons (synaptophysin and neuron-specific enolase). However, they expressed high levels of proliferating cell nuclear antigen and vimentin, markers for proliferating cells. This immunophenotype is consistent with the tumor being at an early stage of differentiation. Therefore, these mice may provide a valuable tool for the study of tumorigenesis, replenishment and differentiation of neural stem cells.

Cytokine-modulated regulation of helper T cell populations

Helper T (Th) cells are a crucial component of the adaptive immune system and are of fundamental importance in orchestrating the appropriate response to pathogenic challenge. They fall into two broad categories defined by the cytokines each produces. Th1 cells produce interferon- gamma and are required for effective immunity to intracellular bacteria, viruses and protozoa whereas Th2 produce IL-4 and are required for optimal antibody production to T-dependent antigens. A great deal of experimental data on the regulation of Th1 and Th2 differentiation have been obtained but many essential features of this complex system are still not understood. Here we present a mathematical model of Th1/Th2 differentiation and cross regulation. We model Fas-mediated activation-induced cell death (AICD) as this process has been identified as an important mechanism for limiting clonal expansion and resolving T cell responses. We conclude that Th2 susceptibility to AICD is important for stabilizing the two polarized arms of the T helper response, and that cell-cell killing, not suicide, is the dominant mechanism for Fas-mediated death of Th1 effectors. We find that the combination of the anti-proliferative effect of the cytokine TGF- beta and the inhibiting influence of IL-10 on T cell activation are crucial controls for Th2 populations. We see that the strengths of the activation signals for each T helper cell subset, which are dependent on the antigen dose, co-stimulatory signals and the cytokine environment, critically determine the dominant helper subset. Switches from Th1- to Th2-dominance may be important in chronic infection and we show that this phenomenon can arise from differential AICD susceptibility of T helper subsets, and asymmetries in the nature of the cross-suppressive cytokine interactions. Our model suggests that in some senses a predominantly type 2 reaction may well be the "default" pathway for an antigen-specific immune response, due to these asymmetries.

Psychometric properties of the Hawaiian Culture Scale--Adolescent Version

This article reports on the psychometric properties of a newly constructed Hawaiian Culture Scale--Adolescent Version. A total of 2,272 Native Hawaiian and 1,170 non-Hawaiian adolescents were administered this 50-item inventory that measures the source of learning the Hawaiian way of life, how much Hawaiian beliefs are valued and important to maintain, how much non-Hawaiian beliefs are valued, Hawaiian blood quantum, and specific cultural traditions (seven subscales = Lifestyles, Customs. Activities, Folklore, Causes-Locations, Causes-Access, and Language Proficiency). The results strongly supported the internal consistency and validity of the measures for both the Hawaiian and non-Hawaiian groups. On the basis of the demographic data, partial support was offered for cross-cultural theories of ethnic identity. More consistent support was found for multiculturalism in Hawai'i's adolescents. Further research is needed to link these measures with indicators of psychological adjustment (e.g., depression, anxiety, substance use).

Psychometric properties of the Hawaiian Culture Scale--Adolescent Version

This article reports on the psychometric properties of a newly constructed Hawaiian Culture Scale--Adolescent Version. A total of 2,272 Native Hawaiian and 1,170 non-Hawaiian adolescents were administered this 50-item inventory that measures the source of learning the Hawaiian way of life, how much Hawaiian beliefs are valued and important to maintain, how much non-Hawaiian beliefs are valued, Hawaiian blood quantum, and specific cultural traditions (seven subscales = Lifestyles, Customs. Activities, Folklore, Causes-Locations, Causes-Access, and Language Proficiency). The results strongly supported the internal consistency and validity of the measures for both the Hawaiian and non-Hawaiian groups. On the basis of the demographic data, partial support was offered for cross-cultural theories of ethnic identity. More consistent support was found for multiculturalism in Hawai'i's adolescents. Further research is needed to link these measures with indicators of psychological adjustment (e.g., depression, anxiety, substance use).

Antibody responses to Yersinia pestis F1-antigen expressed in Salmonella typhimurium aroA from in vivo-inducible promoters

Attenuated mutants of Salmonella typhimurium are being evaluated as delivery systems for a variety of heterologous vaccine antigens. Gene promoters which are induced in vivo can direct the stable expression of genes encoding these antigens. We have investigated the utility of the phoP, ompC, pagC and lacZ gene promoters for expression of the Y. pestis F1-antigen in S. typhimurium SL3261 (aroA). After i.g. (intragastric) dosing the highest level of spleen colonisation was found with recombinant Salmonella expressing F1-antigen from the phoP gene promoter, and this recombinant was most effective in inducing serum and mucosal antibody responses. The use of the pagC gene promoter to direct expression of F1-antigen resulted in the induction of serum and mucosal antibody responses even though the recombinant Salmonella were unable to colonise spleen tissues suggesting that colonisation of these tissues is not essential for the induction of antibody responses.

Psychiatric symptoms in offspring of within vs. across racial/ethnic marriages

A large number of adolescents of interracial ancestry (parents comprising various combinations of African-American, American Indian/Alaska Native, European-American, Chinese, Filipino, Hispanic, Japanese, Korean, Puerto Rican, Samoan, and Tongan ancestry) were contrasted with a monoracial European-American sample in the degree to which they reported symptoms of depression, anxiety, conduct disorder/aggression, and substance abuse. The adolescents of interracial ancestry were subdivided into three groups in terms of parental ancestry: both parents of interracial ancestry, one parent of interracial and the other of monoracial ancestry, and both parents of monoracial but different ancestries. The interracial ancestry groups did not differ significantly from one another or from the European American sample in terms of symptom scores.

Depressive symptoms among Filipino American adolescents

Minority ethnic status has been found to be related to higher levels of depressive symptoms among adolescents and adults. The present study examined the rates of depressive symptoms (as measured by the Center for Epidemiologic Studies Depression Scale: CES-D Scale) of 270 Filipino American adolescents residing in rural and small-town areas of Hawaii. CES-D scores were compared with scores of a White group, and no ethnic differences were found. Compared with Filipino males, Filipino females were found to have higher CES-D scores, with higher mean scores on the majority of the CES-D items. The few Filipino students who reported attempting suicide had moderately high to very high levels of reported depressive symptoms. Lack of ethnic differences may be due to Hawaii's unique cultural mix, where there is no single "majority group" and a high rate of cultural interaction.

Phosphorylation of neurofilament heavy chain side-arms by stress activated protein kinase-1b/Jun N-terminal kinase-3

Neurofilaments comprise three subunit proteins; neurofilament light, middle and heavy chains (NF-L, NF-M and NF-H). The carboxy-terminal domains of NF-M and NF-H form side-arms that project from the filament and that of NF-H contains multiple repeats of the motif lys-ser-pro, the serines of which are targets for phosphorylation. The level of phosphorylation on the lys-ser-pro repeats varies topographically within the cell; in cell bodies and proximal axons, the side-arms are largely non-phosphorylated whereas in more distal regions of axons, the side-arms are heavily phosphorylated. Here we show that stress activated protein kinase 1b (SAPK1b), a major SAPK in neurones will phosphorylate NF-H side-arms both in vitro and in transfected cells. These studies suggest that SAPK1b targets multiple phosphorylation sites within NF-H side-arms. Additionally, we show that glutamate treatment induces activation of SAPK1b in primary cortical neurones and increased phosphorylation of NF-H in cell bodies. This suggests that glutamate causes increased NF-H phosphorylation at least in part by activation of stress activated protein kinases.

Alterations of chromosome arms 1p and 19q as predictors of survival in oligodendrogliomas, astrocytomas, and mixed oligoastrocytomas

PURPOSE

A recent report suggests that alterations of chromosome arms 1p and 19q are associated with chemotherapeutic response and overall survival in anaplastic oligodendroglioma patients treated with procarbazine, lomustine, and vincristine chemotherapy. We set out to further clarify the diagnostic and prognostic implications of these alterations in a broader set of diffuse gliomas, including astrocytic neoplasms and low-grade oligodendrogliomas.

PATIENTS AND METHODS

Fluorescence in situ hybridization (FISH) signals from DNA probes mapping to 1p and 19q common deletion regions were enumerated in 162 diffuse gliomas (79 astrocytomas, 52 oligodendrogliomas, and 31 mixed oligoastrocytomas), collected as part of an ongoing prospective investigation of CNS tumors.

RESULTS

The oligodendroglial phenotype was highly associated with loss of 1p (P =.0002), loss of 19q (P <.0001), and combined loss of 1p and 19q (P <.0001). Combined loss of 1p and 19q was identified as a univariate predictor of prolonged overall survival among patients with pure oligodendroglioma (log-rank, P =.03) and remained a significant predictor after adjusting for the effects of patient age and tumor grade (P <.01). This favorable association was not evident in patients with astrocytoma or mixed oligoastrocytoma.

CONCLUSION

Combined loss of 1p and 19q is a statistically significant predictor of prolonged survival in patients with pure oligodendroglioma, independent of tumor grade. Given the lack of this association in patients with astrocytic neoplasms and the previously demonstrated chemosensitivity of oligodendrogliomas, a combined approach of histologic and genotypic assessment could potentially improve existing strategies for patient stratification and management.

Aberrant CpG-island methylation has non-random and tumour-type-specific patterns

CpG islands frequently contain gene promoters or exons and are usually unmethylated in normal cells. Methylation of CpG islands is associated with delayed replication, condensed chromatin and inhibition of transcription initiation. The investigation of aberrant CpG-island methylation in human cancer has primarily taken a candidate gene approach, and has focused on less than 15 of the estimated 45,000 CpG islands in the genome. Here we report a global analysis of the methylation status of 1,184 unselected CpG islands in each of 98 primary human tumours using restriction landmark genomic scanning (RLGS). We estimate that an average of 600 CpG islands (range of 0 to 4,500) of the 45,000 in the genome were aberrantly methylated in the tumours, including early stage tumours. We identified patterns of CpG-island methylation that were shared within each tumour type, together with patterns and targets that displayed distinct tumour-type specificity. The expression of many of these genes was reactivated by experimental demethylation in cultured tumour cells. Thus, the methylation of particular subsets of CpG islands may have consequences for specific tumour types.

Localization of common deletion regions on 1p and 19q in human gliomas and their association with histological subtype

Allelic alterations of chromosomes 1 and 19 are frequent events in human diffuse gliomas and have recently proven to be strong predictors of chemotherapeutic response and prolonged survival in oligodendrogliomas (Cairncross et al., 1998; Smith et al., submitted). Using 115 human diffuse gliomas, we localized regions of common allelic loss on chromosomes 1 and 19 and assessed the association of these deletion intervals with glioma histological subtypes. Further, we evaluated the capacity of multiple modalities to detect these alterations, including loss of heterozygosity (LOH), fluorescence in situ hybridization (FISH), and comparative genomic hybridization (CGH). The correlation coefficients for detection of 1p and 19q alterations, respectively, between modalities were: 0.98 and 0.87 for LOH and FISH, 0.79 and 0.60 for LOH and CGH, and 0.79 and 0.53 for FISH and CGH. Minimal deletion regions were defined on 19q13.3 (D19S412-D19S596) and 1p (D1S468-D1S1612). Loss of the 1p36 region was found in 18% of astrocytomas (10/55) and in 73% (24/33) of oligodendrogliomas (P < 0.0001), and loss of the 19q13.3 region was found in 38% (21/55) of astrocytomas and 73% (24/33) of oligodendrogliomas (P = 0.0017). Loss of both regions was found in 11% (6/55) of astrocytomas and in 64% (21/33) of oligodendrogliomas (P < 0.0001). All gliomas with LOH on either 1p or 19q demonstrated loss of the corresponding FISH probe, 1p36 or 19q13.3, suggesting not only locations of putative tumor suppressor genes, but also a simple assay for assessment of 1p and 19q alterations as diagnostic and prognostic markers.

Presurgical serum albumin levels predict survival time from glioblastoma multiforme

To determine whether serum albumin levels, before first surgery, predict time until death, 24 glioblastoma multiforme patients newly diagnosed at Ohio State University and Cleveland Clinic Foundation Hospitals between 1993 and 1995 were followed until 1996. Patients with presurgical serum albumin levels below 3.4 mg/dL survived an average (median) of 62 days (95% confidence interval (CI): 34, 135 days) after surgery. Those with serum albumin levels of at least 3.4 mg/dL survived an average of 494 days (95% CI: 241, 624 days). The association between serum albumin level and time until death persists when adjusted for demographic and treatment variables using Cox proportional hazards regression. Adjusted hazard ratios, by quartile of presurgical serum albumin level, are: 1.0, 1.2, 0.1, 0.1 (P-value for trend test = 0.007). In addition to providing a prognostic indicator, presurgical serum albumin levels can be used to evaluate the success of randomization of clinical trials for glioblastoma multiforme therapies. Our findings are consistent with results seen for tumors at other sites. We speculate that our results may be attributable to an association between low serum albumin levels and physiological events associated with angiogenesis.

High-dose carboplatin, thiotepa, and etoposide with autologous stem-cell rescue for patients with recurrent medulloblastoma. Children's Cancer Group

PURPOSE

Medulloblastoma is a highly lethal disease when it recurs. Very few patients survive with conventional treatment. This study evaluated the use of high-dose carboplatin, thiotepa, and etoposide with autologous stem-cell rescue (ASCR) in patients with recurrent medulloblastoma.

METHODS

Chemotherapy consisted of carboplatin 500 mg/m2 (or area under the curve = 7 mg/mL x min via Calvert formula) on days -8, -7, and -6; and thiotepa 300 mg/m2 and etoposide 250 mg/m2 on days -5, -4, and -3; followed by ASCR on day 0. In addition to the study-prescribed therapy, 21 patients received other treatment: neurosurgical resection in seven, conventional chemotherapy in 17, and external-beam irradiation in 11 cases.

RESULTS

Twenty-three patients with recurrent medulloblastoma, aged two to 44 years (median, 13 years) at ASCR, were treated. Three patients died of treatment-related toxicities within 21 days of ASCR; multiorgan system failure in two, and Aspergillus infection with venoocclusive disease in one. Seven of 23 patients (30%) are event-free survivors at a median of 54 months post-ASCR (range, 24 to 78 months). Kaplan-Meier estimates of event-free (EFS) and overall survival are 34% +/- 10% and 46% +/- 11%, respectively, at 36 months post-ASCR.

CONCLUSION

This strategy may provide long-term survival for some patients with recurrent medulloblastoma.