RESUMEN

INTRODUCTION: ES-62, a phosphorylcholine (PC)-containing immunomodulator secreted by the parasitic worm Acanthocheilonema viteae, protects against nephritis in the MRL/Lpr mouse model of systemic lupus erythematosus (SLE). However, ES-62 is not suitable for development as a therapy and thus we have designed drug-like small molecule analogues (SMAs) based around its active PC-moiety. To provide proof of concept that ES-62-based SMAs exhibit therapeutic potential in SLE, we have investigated the capacity of two SMAs to protect against nephritis when administered to MRL/Lpr mice after onset of kidney damage. METHODS: SMAs 11a and 12b were evaluated for their ability to suppress antinuclear antibody (ANA) generation and consequent kidney pathology in MRL/Lpr mice when administered after the onset of proteinuria. RESULTS: SMAs 11a and 12b suppressed development of ANA and proteinuria. Protection reflected downregulation of MyD88 expression by kidney cells and this was associated with reduced production of IL-6, a cytokine that exhibits promise as a therapeutic target for this condition. CONCLUSIONS: SMAs 11a and 12b provide proof of principle that synthetic compounds based on the safe immunomodulatory mechanisms of parasitic worms can exhibit therapeutic potential as a novel class of drugs for SLE, a disease for which current therapies remain inadequate.

Asunto(s)

RESUMEN

Evidence from human studies suggests that parasitic worm infection can protect humans against rheumatoid arthritis (RA) and this idea is strengthened by data generated in model systems. Although therapeutic use of parasitic worms is currently being explored, there are obvious benefits in pursuing drug development through identification and isolation of the 'active ingredients'. ES-62 is a secreted glycoprotein of the filarial nematode Acanthocheilonema viteae, which we have found to protect against the development of collagen-induced arthritis (CIA) in mice. ES-62 activity is dependent on the inflammatory phenotype of the local environment and protection arises via inhibition of Th17- and γδT cell-dependent IL-17 production. At the same time, NK and NK T cell IL-17 production is left intact, and such selectivity suggests that ES-62 might make a particularly attractive therapeutic for RA. However, as a potentially immunogenic protein, ES-62 is unsuitable for development as a drug. Nevertheless, ES-62 activity is dependent on covalently attached phosphorylcholine (PC) residues and we have therefore produced a library of PC-based drug-like ES-62 small-molecule analogues (SMAs) as an alternative therapeutic strategy. Screening this library, we have found an ES-62 SMA that mirrors ES-62 in protecting against CIA and by the same IL-17-dependent mechanism of action.

Asunto(s)

RESUMEN

We report here the specific interaction between several members of the human galectin family with the three developmental stages of several genetic lineages of the protozoan parasite Trypanosoma cruzi. We provide data of specific and differential binding of human galectin (gal)-1, -3, -4, -7 and -8 to 14 strains of T. cruzi that belong to the six genetic lineages representing the genetic diversity of the parasite. It is shown that galectins preferentially bind forms present in the host, trypomastigotes and amastigotes, compared with the non-infective epimastigote present on the intestinal tract of the vector, reflecting the changes on glycosylation that occur during the metacyclogenesis and amastigogenesis process. Also, it is evidenced that galectin binding to the parasites promotes binding to the host cells and higher infection rates. In addition, evidence is provided indicating that the intracellular amastigotes may take over the cytosolic pool of some galectins when released to the extracellular medium. Finally, by applying unweighted pair group method analysis to the galectin-binding profile to either cell-derived trypomastigotes or amastigotes, we show that the differential-binding profile by the host galectins to the six lineages resembles the clustering based in genetic data. Therefore, the differential-binding profile for the six lineages could have implications in the immunopathology of Chagas' disease, affecting the complex network of immune responses on which galectins mediate, thus providing linkage clues to the notion that different lineages may be related to different clinical forms of the disease.

Asunto(s)

RESUMEN

Parasitic worms are able to survive in their mammalian host for many years due to their ability to manipulate the immune response by secreting immunomodulatory products. It is increasingly clear that, reflecting the anti-inflammatory actions of such worm-derived immunomodulators, there is an inverse correlation between helminth infection and autoimmune diseases in the developing world. As the decrease in helminth infections due to increased sanitation has correlated with an alarming increase in prevalence of such disorders in industrialized countries, this 'hygiene hypothesis' has led to the proposal that worms and their secreted products offer a novel platform for the development of safe and effective strategies for the treatment of autoimmune disorders. In this study we review the anti-inflammatory effects of one such immunomodulator, ES-62 on innate and adaptive immune responses and the mechanisms it exploits to afford protection in the murine collagen-induced arthritis (CIA) model of rheumatoid arthritis (RA). As its core mechanism involves targeting of interleukin (IL)-17 responses, which despite being pathogenic in RA are important for combating infection, we discuss how its selective targeting of IL-17 production by T helper type 17 (Th17) and γδ T cells, while leaving that of CD49b(+) natural killer (NK and NK T) cells intact, reflects the ability of helminths to modulate the immune system without immunocompromising the host. Exploiting helminth immunomodulatory mechanisms therefore offers the potential for safer therapies than current biologicals, such as 'IL-17 blockers', that are not able to discriminate sources of IL-17 and hence present adverse effects that limit their therapeutic potential.

Asunto(s)

RESUMEN

The search for disease-associated T helper 2 (Th2) Leishmania antigens and the induction of a Th1 immune response to them using defined vaccination protocols is a potential strategy to induce protection against Leishmania infection. Leishmania infantum LiP2a and LiP2b acidic ribosomal protein (P proteins) have been described as prominent antigens during human and canine visceral leishmaniasis. In this study we demonstrate that BALB/c mice infected with Leishmania major develop a Th2-like humoral response against Leishmania LiP2a and LiP2b proteins and that the same response is induced in BALB/c mice when the parasite P proteins are immunized as recombinant molecules without adjuvant. The genetic immunization of BALB/c mice with eukaryotic expression plasmids coding for these proteins was unable to redirect the Th2-like response induced by these antigens, and only the co-administration of the recombinant P proteins with CpG oligodeoxynucleotides (CpG ODN) promoted a mixed Th1/Th2 immune response. According to the preponderance of a Th2 or mixed Th1/Th2 responses elicited by the different regimens of immunization tested, no evidence of protection was observed in mice after challenge with L. major. Although alterations of the clinical outcome were not detected in mice presensitized with the P proteins, the enhanced IgG1 and interleukin (IL)-4 response against total Leishmania antigens in these mice may indicate an exacerbation of the disease.

Asunto(s)

RESUMEN

BACKGROUND: Skewed X chromosome inactivation may be more common in women with epithelial ovarian cancer and early-onset breast cancer. We tested this hypothesis in a group of 235 breast cancer patients and 253 controls (mean age 45.8 years) from a larger population based case control study. METHODS: We measured X chromosome inactivation with the AR gene assay in lymphocyte DNA digested with the methylation specific enzyme HpaII. We judged skewness using an adjusted measure (relative to the undigested sample) with a cut point of 75%, and an unadjusted measure where skewed was defined as > 90% of the signal from one allele in the HpaII digested sample. RESULTS: There were no significant differences in any of the skewing measures between cases and controls. Using the adjusted skewing measure among pre-menopausal subjects under the age of 50, 14% of cases versus 11% of controls were skewed, OR = 1.2, 95% CI 0.6 to 2.3; using the unadjusted measure, OR = 0.9, 95% CI 0.4 to 2.0. CONCLUSIONS: While we cannot rule out a subtle difference of approximately twofold or less, we have failed to find a significant difference in the prevalence of skewed X chromosome inactivation in younger women with breast cancer compared to controls.

Asunto(s)

RESUMEN

The genetic structure of a population of multidrug-resistant nontypeable (unencapsulated) Haemophilus influenzae strains isolated at a hospital in Barcelona, Spain, was investigated by using multilocus enzyme electrophoresis to determine the allelic variation in 15 structural loci. In our study we have also included some antimicrobial agent-susceptible strains isolated at the same hospital. All enzymes were polymorphic for two to eight electromorphs, and the analysis revealed 43 distinct electrophoretic types among the 44 isolates. The mean genetic diversity of the entire population was 0.55. Multilocus linkage disequilibrium analysis of the isolates revealed a strong association between alleles, suggesting little possibility of recombination. Furthermore, the dendrogram and the allele mismatch distribution are typical of a population with no extensive genetic mixing.

Asunto(s)

RESUMEN

BACKGROUND: Mutations in the ligand-binding domain of the thyroid hormone receptor beta (TR beta) gene cause the syndrome of resistance to thyroid hormone (RTH). The clinical phenotype results from the antagonism of the normal TR alpha and the non-mutated TR beta alleles by the TR beta 1 mutants, via a dominant negative effect. There is, however, marked heterogeneity of organ resistance within and among kindreds with RTH. This study examines the potential role of cell type in modulating the dominant negative potency of human TR beta 1 (h-TR beta 1) mutants. MATERIALS AND METHODS: Transient transfections were performed in HeLa and NIH3T3 cells, using a wild type (WT) and three naturally occurring mutant h-TR beta 1 constructs, and three natural thyroid hormone response elements (TREs). Immunocytochemistry was performed to detect levels of TR beta 1 expression in these two cell types. In order to determine how TR beta 1 interacts with other cellular partners, gel-shift analyses using HeLa and NIH3T3 nuclear extracts were performed. RESULTS: Transfection studies using WT h-TR beta 1 in HeLa and NIH3T3 cells, showed that the 3,3',5-triiodothyronine (T3)-induced transactivation of the different TREs varied between cell types. Unlike the non-T3-binding h-TR beta 1 mutant, PV, mutants ED and OK displayed the expected T3-induced dose responsiveness in these two cell types. For each TRE examined, the magnitude of the dominant negative effect varied between the cell types. The levels of receptor expression in HeLa and NIH3T3 cells were identical, as determined by immunocytochemistry. Gel-shift analyses showed differences in the formation of hetero- and homodimers depending on both the cell type and TRE motif. CONCLUSIONS: The cell type in which a mutant receptor operates affects the relative amounts of hetero- and homodimers. Together with the nature of the mutation and the TRE-motif, this could modulate the dominant negative action of mutant receptors in different tissues, which, in turn, could contribute to the variable phenotypic characteristics of RTH.

Asunto(s)

Asunto(s)

RESUMEN

In 1983, one-quarter of married Guatemalan women aged 15-44 years were using contraception, and female sterilization was the most prevalent method. Fertility rates for the population were at correspondingly high levels, with an overall total fertility rate of about six births per woman. Contraceptive prevalence varied by residence and ethnic group; less than 5 percent of currently married Indian women and about 50 percent of married women in the capital city area were using contraception. From 1978 to 1983, prevalence increased overall by six percentage points, with surgical contraception accounting for most of the increase. Findings of the study suggest that different strategies need to be employed among Ladino and Indian women in order to increase contraceptive prevalence in these subgroups.

PIP: A 1983 survey shows that Guatemala continues to have a relatively low level of contraceptive use by Latin American standards. However, by comparing the results of the 1983 survey with those of a similar survey conducted in 1978, it is clear that contraceptive use has increased slightly. During the 5-year interval between these surveys, the % of married women aged 15-44 years old who were using contraception increased from 19 to 25%. Most of the increase in prevalence was in the use of sterilization, which was found to be the most prevalent method in both surveys. This report describes the results of the 1983 Family Planning and Maternal/Child Health Survey conducted in Guatemala. Also discussed are trends in fertility, breastfeeding, contraceptive use, source of contraception, and women at risk of unplanned pregnancies since the 1978 survey. The 1983 data indicate that mean parity was higher for Indian women than for Ladino women at every age above 20. The mean parity for all women in the 1983 survey is slightly less than that of women in the 1978 survey, but of generally the same magnitude. Overall, the mean duration of breastfeeding estimated from the 1983 survey is 18 months. Postpartum amenorrhea averages about 12 months for all groups. A comparison of duration of breastfeeding for respondents in the 1978 survey with those in the 1983 survey provides no evidence of a trend away from breastfeeding in Guatemala. Overall, 1/4 of married women aged 15-44 were using contraceptive methods at the time of the 1983 survey. The most prevalent method was female sterilization (10%), which, together with male sterilization, accounted for 45% of all contraceptive use. The 2nd most commonly used method, oral contraceptives, had a relatively low prevalence of 5%, followed by rhythm, the IUD, injectables and vaginal methods, and finally, the condom. Contraceptive use also varied by age, reaching a peak among married women 30-39 years old and was lowest for those 15-24. Use of contraception was strongly related to education, being lowest among women with little or formal education. Results in general suggest that contraceptive use is part of a larger predisposition among women to use modern health care. Among Indians, the major reason given for nonuse of contraceptives unrelated to pregnancy was lack of knowledge of contraception or where to obtain family planning services. Among Ladinos, the most frequently mentioned reason was fear of contraception or fear of side effects. The methods of choice for nonusers desiring to use a method were oral contraceptives (27%), sterilization (18%) and injectables (14%). The survey data indicate that the family planning program in Guatemala should be oriented toward high parity, married, nonworking women living in the interior, both Ladino and Indian, who have less than a primary school education. Family planning efforts need to incorporate different approaches for Ladino and Indian women.

Asunto(s)

RESUMEN

In this study of 1,600 men aged 25-50 from semi-rural Guatemala, three-fourths had heard of vasectomy. Among these, 54 per cent approved of it. However, the survey reveals a widespread lack of knowledge regarding the procedure, as well as negative perceptions or doubts about its effect on sexual performance, ability to do hard work, health, and manhood. One-fourth of the respondents who knew of vasectomy and who desired no more children expressed interest in having the operation, a finding which raises questions as to the potential (unrecognized) demand for vasectomy in other developing countries.

Asunto(s)

RESUMEN

As community-based distribution (CBD) systems for the delivery of contraceptive methods are implemented in developing countries around the world, there is growing interest in making these programs more effective. Previous research on the CBD program in Guatemala indicated the importance of the role of the spouse: those community volunteers (called "distributors") who received assistance from their spouses were more effective in selling contraceptives than those who did not. The current experiment was designed to test the effect of providing the spouses of distributors with a formal 3-day training course on family planning and contraceptives. "Effect" was operationally measured in terms of the level of contraceptive sales. To this end sales data were compared for the experimental group (33 distributors whose spouses received the training) and the control group (33 distributors whose spouses wanted to attend the training but could not because their primary occupation did not allow them to be absent) for periods of 6 months prior to and 6 months following the training. The results indicate that sales among the experimental group increased significantly, whereas no such increase was found among the controls. This suggests a strategy for increasing the effectiveness of community volunteer workers that has received relatively little attention in the literature to date.

Asunto(s)

RESUMEN

PIP: Report of a study comparing 500 men and 419 women who had undergone voluntary sterilization in Guatemala City, in terms of their sociodemographic characteristics, attitudes and motivations regarding the operation, reactions to the quality of attention received in the clinic, postoperative complaints, and the effect of the operation on health and sex life. In both groups over 90% reported no regret about the operation. Changes in health status or sex life after the operation emerged as very important correlates of satisfaction among both men and women. Acceptors tended to be married or live in consensual union, be Catholic but not very religious, have an average of 4 children, have used contraceptives prior to the operation (especially the pill), have a favorable attitude toward the attention received from clinic personnel, and report no change or a change for the better in their general health and sex life. However, the following differences did emerge between men and women: men were better educated and held more prestigious jobs; most men reported their wives to be in favor of their vasectomy, where 33% of the women said that their husbands had been indifferent; men were more likely to experience pain or discomfort in the 1st few days after the operation but less likely to lose time from work or lost fewer days (4.0 versus 5.5); among women, pain or discomfort with the operation was related to satisfaction--those experiencing pain were more likely to regret having had the operation; men, by contrast, were more likely than women to experience pain or discomfort, but this was not related to satisfaction with the operation a year or more afterwards. Recommendations include studying the effect of increased educational/promotional efforts among men with lower levels of education and more careful screening to detect individuals who may already be experiencing some type of sexual problem or have unrealistic expectations. Reasons for the higher rate of female sterilizations in Guatemala (15:1 or 5.7 tubal ligations to 1 vasectomy) include perceptions of less negative psychological consequences, attitudes of health practitioners, and use of the procedure on an outpatient basis. In general Guatemala has a low rate of family planning acceptance compared to surrounding countries.^ieng

Asunto(s)

RESUMEN

PIP: 500 of the 1576 men vasectomized in the Asociacion ProBienestar de la Familia program between January 1977 and December 1979 were interviewed 12-36 months after vasectomy. 99.4% were married or lived in consensual unions, average age at the time of operation was 36, and average number of children was 3.9. More were highly educated than the general population and 78.2% were Catholic. Primary reasons for undergoing vasectomy included limitation of family size (61.2%), economic considerations (23.6%), avoidance of female contraceptives considered to be harmful (5.4%), relieving the wife of the burden of contraception (4.8%), and other (5.0%). 52.4% chose vasectomy over female sterilization because it is simpler, faster, and less risky. Primary source of referral was friend or relative. 79.4% reported prior use of contraception: 54.4% pills, 13.6% IUD, 12.3% condom, 7.8% vaginal methods, and 11.9% other. Most wives favored the operation. 40% reported discomfort in the 1st few days, primarily pain or inflammation of the testicles, 15% lost time from work, and 47 (9.4%) reported problems 1 month after the operation. Most men considered their general health, sex drive, and marital relations to be unchanged or improved. Only 73.8% had postoperative sperm checks; in 1.9% the check was positive. In 9 of the 500 cases (1.8%) the wife became pregnant. 97.4% said they had never regretted having the operation and 93.2% would recommend the operation to others. Further analysis indicated that satisfaction was not a function of sociodemographic characteristics, attitudes toward the clinic, postoperative discomfort, or wife's attitude. Dissatisfaction stemmed from failure of the operation or perceived negative effect of the operation on one's health or sex life.^ieng

Asunto(s)

RESUMEN

A study conducted by the Asociación ProBienestar de la Familia (APROFAM) of Guatemala among 177 urban and 233 rural distributors in its CBD programs indicates a number of characteristics related to distributor success (measured by volume of contraceptives sold). Among urban distributors the most important factors were number of months the distributor had worked in the program, location of the CBD post, and the fact of promoting the service by displaying a poster and organizing community meetings about family planning. Among rural distributors, performance was highest among those who received assistance from their spouse, had local competition in the sale of contraceptives, promoted family planning by visiting their neighbors and organizing group meetings, had a higher level of education, and received frequent supervision. In general, factors involving program design and task performance were better predictors of distributor performance than the sociodemographic characteristics of the distributor.

Asunto(s)

Asunto(s)