Larvicidal activity of the skin secretion of Rhinella marina and Rhaebo guttatus (Anura: Bufonidae) against the Brazilian malaria vector, Anopheles darlingi (Diptera: Culicidae)

@#Malaria, a mosquito-borne disease, is caused by protozoa of the genus Plasmodium and constitutes a serious public health problem. Because current insecticides used to control malaria face resistance due to continuous use, new alternatives are prompted. Considering this context, and the insecticidal potential of vertebrate venoms/secretions, crude and methanolic extracts from two frog species were tested as larvicides against Anopheles darlingi. Skin secretions of Rhinella marina and Rhaebo guttatus were obtained by manual stimulation. Then, methanol was added to obtain steroidal fractions from both venoms. Mosquitos were captured in suburban areas of Porto Velho and An. darlingi females were later fed with blood and stimulated to oviposit. The larvae were fed with fish food until the 3rd and 4th instars. For the larvicidal assays, crude secretions and methanolic fractions of both frog species were evaluated, and larvae mortality was recorded after 48 hours. Crude extracts and steroidal fractions from both species had larvicidal effects, with an LC50 of 127.5 and 133 ppm for the crude extract and steroidal fraction of R. marina, and an LC50 of 37.5 and 35.8 ppm for the crude extract and steroidal secretion of R. guttatus, respectively. The present work reports for the first time the larvicidal effects of the skin secretions from bufonid species occurring in the western Amazon region. Further studies should be carried out to investigate the purified components responsible for the observed activity.

Reduced growth in wild juvenile sockeye salmon Oncorhynchus nerka infected with sea lice.

Daily growth rings were examined in the otoliths of wild juvenile sockeye salmon Oncorhynchus nerka to determine whether infection by ectoparasitic sea lice Caligus clemensi and Lepeophtheirus salmonis was associated with reduced host body growth, an important determinant of survival. Over 98% of the sea lice proved to be C. clemensi and the fish that were highly infected grew more slowly than uninfected individuals. Larger fish also grew faster than smaller fish. Finally, there was evidence of an interaction between body size and infection status, indicating the potential for parasite-mediated growth divergence.

Alkylation of histidine residues of Bothrops jararacussu venom proteins and isolated phospholipases A2: a biotechnological tool to improve the production of antibodies.

Crude venom of Bothrops jararacussu and isolated phospholipases A2 (PLA2) of this toxin (BthTX-I and BthTX-II) were chemically modified (alkylation) by p-bromophenacyl bromide (BPB) in order to study antibody production capacity in function of the structure-function relationship of these substances (crude venom and PLA2 native and alkylated). BthTX-II showed enzymatic activity, while BthTX-I did not. Alkylation reduced BthTX-II activity by 50% while this process abolished the catalytic and myotoxic activities of BthTX-I, while reducing its edema-inducing activity by about 50%. Antibody production against the native and alkylated forms of BthTX-I and -II and the cross-reactivity of antibodies to native and alkylated toxins did not show any apparent differences and these observations were reinforced by surface plasmon resonance (SPR) data. Histopathological analysis of mouse gastrocnemius muscle sections after injection of PBS, BthTX-I, BthTX-II, or both myotoxins previously incubated with neutralizing antibody showed inhibition of the toxin-induced myotoxicity. These results reveal that the chemical modification of the phospholipases A2 (PLA2) diminished their toxicity but did not alter their antigenicity. This observation indicates that the modified PLA2 may provide a biotechnological tool to attenuate the toxicity of the crude venom, by improving the production of antibodies and decreasing the local toxic effects of this poisonous substance in animals used to produce antivenom.

Does predation risk influence habitat use by northern redbelly dace Phoxinus eos at different spatial scales?

This study investigated the relationship between spatial variations in predation risk and abundance of northern redbelly dace Phoxinus eos at both macroscale (littoral v. pelagic zones) and microscale (structured v. open water habitats in the littoral zone) of Canadian Shield lakes. Minnow traps were placed in both structured and open water habitats in the littoral zone of 13 Canadian Shield lakes, and estimates of the relative predation risk of P. eos in both the pelagic and the littoral zones were obtained from tethering experiments. Results showed that (1) the mean abundance of P. eos in the littoral zone was positively correlated with the relative predation risk in the pelagic zone, (2) P. eos preferentially used structured over open water habitats in the littoral zone and (3) this preference was not related to the relative predation risk in the littoral zone but decreased as the relative predation risk increased in the pelagic zone. At the lake level, these results support the hypothesis that P. eos enter the littoral zone to avoid pelagic piscivores. At the littoral zone level, the results do not necessarily contradict the widely accepted view that P. eos preferentially use structured over open habitats to reduce their predation risk, but suggest that flexibility in antipredator tactics (e.g. shelter use v. shoaling) could explain the spatial distribution of P. eos between structured and open water habitats.

Sea lice escape predation on their host.

Parasites seldom have predators but often fall victim to those of their hosts. How parasites respond to host predation can have important consequences for both hosts and parasites, though empirical investigations are rare. The exposure of wild juvenile salmon to sea lice (Lepeophtheirus salmonis) from salmon farms allowed us to study a novel ecological interaction: the response of sea lice to predation on their juvenile pink and chum salmon hosts by two salmonid predators-coho smolts and cut-throat trout. In approximately 70% of trials in which a predator consumed a parasitized prey, lice escaped predation by swimming or moving directly onto the predator. This trophic transmission is strongly male biased, probably because behaviour and morphology constrain female movement and transmission. These findings highlight the potential for sea lice to be transmitted up marine food webs in areas of intensive salmon aquaculture, with implications for louse population dynamics and predatory salmonid health.

Clinical characteristics of women with a history of childhood abuse: unhealed wounds.

OBJECTIVES: To determine the prevalence of childhood physical or sexual abuse in women seen in primary care practices; to identify physical and psychologic problems associated with that abuse; and to compare the effects of childhood physical vs sexual abuse and childhood vs adult abuse. DESIGN: Cross-sectional, self-administered, anonymous survey. SETTING: Four community-based, primary care internal medicine practices. PATIENTS: A total of 1931 women of varied age and marital, educational, and economic status examined from February through July 1993. MAIN OUTCOME MEASURES: Prevalence of physical and sexual abuse, physical symptoms, psychological symptoms (Symptom Checklist-22), alcohol abuse (CAGE questions), and street drug use. RESULTS: Of the 1931 respondents, 424 (22.0%) reported childhood or adolescent physical or sexual abuse. Compared with women who reported never having experienced abuse (n=1257), women who reported abuse as children but not adults (n=204) had more physical symptoms (mean+/-SE, 6.2+/-0.2 vs 4.0+/-0.9; P<.001) and had higher scores for depression, anxiety, somatization, and interpersonal sensitivity (low self-esteem) (P<.001); were more likely to be abusing drugs (prevalence ratio [PR], 4.7; 95% confidence interval [CI], 2.9-7.6) or to have a history of alcohol abuse (PR, 2.2; 95% CI, 1.5-3.2); were more likely to have attempted suicide (PR, 3.7; 95% CI, 2.6-5.1); and were more likely to have had a psychiatric admission (PR, 3.2; 95% CI, 2.2-4.7). Women abused only as children did not differ from women who reported current, but not childhood, abuse in number of physical symptoms, emotional distress, substance abuse, or suicide attempts. Patients who reported both childhood and adult abuse had higher levels of psychological problems and physical symptoms than those who reported childhood or adult abuse alone. CONCLUSIONS: Childhood physical or sexual abuse is associated with adult health problems including physical symptoms, psychological problems, and substance abuse; for many variables, this association is as strong as for patients experiencing current abuse.

The "battering syndrome": prevalence and clinical characteristics of domestic violence in primary care internal medicine practices.

OBJECTIVES: To determine the prevalence of domestic violence among female patients and to identify clinical characteristics that are associated with current domestic violence. DESIGN: Cross-sectional, self-administered, anonymous survey. SETTING: 4 community-based, primary care internal medicine practices. PATIENTS: 1952 female patients of varied age and marital, educational, and economic status who were seen from February to July 1993. MEASUREMENTS: The survey instrument included previously validated questions on physical and sexual abuse, alcohol abuse, and emotional status and questions on demographic characteristics, physical symptoms, use of street drugs and prescribed medications, and medical and psychiatric history. RESULTS: 108 of the 1952 respondents (5.5%) had experienced domestic violence in the year before presentation. Four hundred eighteen (21.4%) had experienced domestic violence sometime in their adult lives, 429 (22.0%) before age 18 years, and 639 (32.7%) as either an adult or child. Compared with women who had not recently experienced domestic violence, currently abused patients were more likely to be younger than 35 years of age (prevalence ratio [PR], 4.1 [95% CI, 2.8 to 6.0]); were more likely to be single, separated, or divorced (PR, 2.5 [CI, 1.7 to 3.6]); were more likely to be receiving medical assistance or to have no insurance (PR, 4.3 [CI, 2.8 to 6.6]); had more physical symptoms (mean, 7.3 +/- 0.38 compared with 4.6 +/- 0.08; P < 0.001); had higher scores on instruments for depression, anxiety, somatization, and interpersonal sensitivity (low self-esteem) (P < 0.001); were more likely to have a partner abusing drugs or alcohol (PR, 6.3 [CI, 4.4 to 9.2]); were more likely to be abusing drugs (PR, 4.4 [CI, 1.9 to 10.4]) or alcohol (PR, 3.1 [CI, 1.5 to 6.5]); and were more likely to have attempted suicide (PR, 4.3 [CI, 2.8 to 6.5]). They visited the emergency department more frequently (PR, 1.7 [CI, 1.2 to 2.5]) but did not have more hospitalizations for psychiatric disorders. In a logistic regression model into which 9 risk factors were entered, the likelihood of current abuse increased with the number of risk factors, from 1.2% when 0 to 1 risk factors were present to 70.4% when 6 to 7 risk factors were present. CONCLUSIONS: In a large, diverse, community-based population of primary care patients, 1 of every 20 women had experienced domestic violence in the previous year; 1 of every 5 had experienced violence in their adult life; and 1 of every 3 had experienced violence as either a child or an adult. Current domestic violence is associated with single or separated status, socioeconomic status, substance abuse, specific psychological symptoms, specific physical symptoms, and the total number of physical symptoms.

PIP: This cross-sectional study determined the prevalence of domestic violence among female patients presenting to four community-based primary care internal medicine practices in Baltimore, Maryland, between February and July, 1993. Furthermore, it identified clinical characteristics associated with domestic violence. A total of 1952 female patients of diverse socioeconomic backgrounds participated in a self-administered, anonymous survey that solicited data on physical and sexual abuse, alcohol abuse, emotional status, demographic characteristics, physical symptoms, use of street drugs and prescribed medications, and medical and psychiatric history. Of the 1952 respondents, 108 (5.5%) had experienced domestic violence in the previous year, 418 (21.4%) had experienced violence sometime in their adult lives, 429 (22%) before age 18 years, and 639 (32.7%) as either an adult or a child. Current violence status is associated with single or separated status, substance abuse, specific psychological symptoms, specific physical symptoms, and the total number of physical symptoms. In a logistic regression model, the likelihood of current abuse increased with the number of risk factors. The magnitude of these associations supports the idea that domestic violence is a significant medical public health problem. Detection of domestic violence by physicians or other health care professionals might alter both the diagnostic and treatment plans for these women.

The development of a new geographic coding system for the Continuous Work History Sample.

This article describes the statistical development of the geographic coding system used to identify worker location for the Continuous Work History Sample. The new system--which is planned for implementation for data year 1993--will provide more accurate geographic distributions of workers within a residence concept than the old system could provide within an employer location concept. The article also presents the results of a pilot study that tested the operational aspects of the new system. The results provide some preliminary estimates of the effect of the revised codes on the geographic distribution of workers.

The development and use of industry data by the Social Security Administration.

Over the past few years the Social Security Bulletin has published a series of technical articles that describe various Social Security Administration (SSA) data files. This article provides an overview of SSA's industry-related data files and statistical systems from both a current and a historical perspective. The author begins by explaining how SSA first collected business data from employers (starting in 1937) as a by-product of the requirement that employers report employee wages for benefit computation purposes. She describes the administrative methods by which the data are collected, SSA's coordination of its activities with other agencies, the data collection forms used, the scheme by which the data are coded, and the employer files into which the data are classified. In her closing, the author provides examples of the various uses of the industry data and the ways that these data relate to SSA's statistical program needs and to those of other agencies as well.

Neurogenic pulmonary edema and missile emboli.

A case of missile emboli to a major intracranial vessel resulting in fulminant pulmonary edema is reported. A discussion of the etiology of neurogenic pulmonary edema (NPE) is presented. The cause is thought to be a marked increase in pulmonary artery pressure, due to a massive catechol release in the CNS, and possibly secondary to post-capillary sphincteric constriction. Missile emboli to the cerebral arteries should be removed in order to avoid distal embolization and infarction. The case reported appears to represent the first documented case of missile emboli causing NPE.