Is there immunity to Schistosoma japonicum?

The Oriental schistosome, Schistosoma japonicum, unlike the other two major schistosomes that infect humans (S. mansoni and S. haematobium), is a zoonotic species. The transmission dynamics and the potential effects of host-related regulatory factors, including immunity, are likely to be distinct for this parasite. Here, Allen Ross and collaborators from Australia, China and the Philippines discuss recently published and established epidemiological and laboratory data bearing on anti-infection immunity to Asian schistosomiasis, and contrast these findings with the emerging picture of development of anti-infection immunity against the African schistosomes. Implications for vaccines and other control strategies for schistosomiasis japonica are also discussed.

Lack of DNA-damaging activity of five non-nutritive sweeteners in the rat hepatocyte/DNA repair assay

The non-nutritive sweeteners acesulfame-K, aspartame, cyclamate, saccharin and sucralose were tested for DNA damaging activity in the rat hepatocyte/DNA repair assay. Using hepatocytes from F344 and Sprague-Dawley male rats, all were inactive despite strong responses for the positive control, 2-aminofluorene.

Malaria control in central Malaita, Solomon Islands. 1. The use of insecticide-impregnated bed nets

The present study investigated the use of insecticide-impregnated bed nets by communities in central Malaita, Solomon Islands. Qualitative and quantitative data were collected by: (1) questionnaire administration to 124 care-givers of children aged 0-10 years of age; (2) 20 focus group discussions; (3) two structured observations of bed net re-impregnation, and (4) interviews with key informants. Ninety-four percent of all care-givers had bed nets, but only 62% had sufficient bed nets for all household members. Fifty-two percent used bed nets throughout the year and 70% of care-givers reported that all their children slept under bed nets. Although coastal householders considered malaria and mosquitoes more of a problem than inland householders, overall bed net compliance did not differ. Factors affecting bed net ownership were cost and community expectation of free bed nets. Bed net use was affected by four factors: (1) seasonality (99% used bed nets during the rainy season, 52% used them all year); (2) mosquito nuisance (59% of respondents reported that protection against mosquitoes was the main reason for using a bed net); (3) weather (68% of care-givers would not use a bed net if the weather was hot), and (4) low density of mosquitoes (respondents who used bed nets as protection against mosquito nuisance were more likely not to use bed nets when mosquitoes were few than those who used bed nets for malaria protection (odds ratio (OR), 3.9; 95% confidence interval (CI), 1.4-12.0). Protection against malaria was the main reason children slept under bed nets. Children from households where bed nets were used for malaria protection were more likely to sleep under bed nets than children from households where nets were used as protection from mosquitoes only (OR, 2.7; 95% CI, 1.3-5.9). Other factors that affected children's bed net use were, age (users were significantly younger than non-users; chi(2)=7.9, degrees of freedom=1, P=0.005) and sufficiency of bed nets (OR, 2.0; 95% CI, 1. 3-7.0).

Lack of oxidative DNA damage or initiation of carcinogenesis in the kidneys of male F344 rats given subchronic exposure to p-dichlorobenzene (pDCB) at a carcinogenic dose

p-Dichlorobenzene (pDCB) is a male rat kidney carcinogen believed to act through alpha2u-globulin nephropathy. Recent data on metabolism, however, suggest a potential for generating oxidative stress. To examine possible mechanisms of kidney carcinogenesis, pDCB was studied for ability to produce 8-oxodeoxyguanosine (8-oxodG) in kidney nuclear DNA and for initiating activity in a two-stage renal carcinogenesis model. F344 male rats were given pDCB by intragastric instillation, 5 days/week for 13 weeks at 300 mg/kg per day, which is a carcinogenic dose with chronic administration. To assess initiation after exposure, trisodium nitrilotriacetic acid (NTA), a kidney tumor promoter was given in the drinking water at 1,000 ppm for 39 weeks. At the end of the exposure segment, pDCB did not produce an increase of 8-oxodG levels in the kidney nuclear DNA in contrast to potassium bromate (KBrO3). Following NTA promotion, no neoplastic lesions occurred in rats given pDCB, although diethylnitrosamine carcinogenesis was enhanced. Thus, pDCB did not produce oxidative DNA damage in the rat kidney or effect initiation of kidney carcinogenesis. These data suggest that oxidative stress is not involved in pDCB-induced renal carcinogenesis. The alpha2u-globulin-mediated chronic nephropathy probably acts as a promoter, not an initiation of renal carcinogenesis. Accordingly, pDCB is assessed to have no cancer hazard to humans who are not susceptible to the alpha2u-globulin nephropathy.

Epidemiology of Schistosoma japonicum in China: morbidity and strategies for control in the Dongting Lake region

Dongting Lake, covering a very large surface water area of 2691km(2), is located in Hunan Province in the southern part of the People's Republic of China. It is the second-largest freshwater lake in China and plays an important role in regulating the amount of water in the Yangtze River, China's longest river. The annual water level of the lake changes by as much as 15m, rising in summer and falling in winter. Asian schistosomiasis has been endemic in the Dongting Lake region for centuries and it has had a devastating effect on the public health of the local people. After a difficult struggle for more than four decades, a concerted programme, supported by the World Bank Loan and instigated in 1992, has resulted in remarkable progress in the control of the disease in many endemic areas of the region. However, the great challenge remains to consolidate and maintain the achievements made to date. The Schistosoma japonicum intermediate host (Oncomelania hupensis hupensis) snail habitats are huge, estimated at 1768km(2) in 1996; these are increasing at a rate of 34.7km(2) annually due to high silt deposition from the Yangtze River itself and from the connecting rivers in Hunan province, and construction of embankments in the Dongting Lake region. It is anticipated that the construction of the Three Gorges Super Dam, the largest engineering project ever undertaken, will substantially extend the range of the snail habitats and increase the number of new schistosomiasis cases. In many areas, human re-infections with S. japonicum after drug (praziquantel) treatment remain unacceptably high (up to 20% of those treated are re-infected annually) due to occupational (mainly fishing) water contact. This paper reviews the history and the current status of schistosomiasis control in the lake region, it explores the epidemiological factors which influence the prevalence of the infection and the disease it causes, and it provides insight into future approaches to control which might finally eradicate the infection.

Two-year impact of praziquantel treatment for Schistosoma japonicum infection in China: re-infection, subclinical disease and fibrosis marker measurements

We studied a community cohort of 193 individuals exposed to endemic Schistosoma japonicum infection in the Dongting Lake region of China to assess subclinical morbidity and the 2-year benefit of curative therapy (praziquantel) administered in 1996. Prevalence and intensity of S. japonicum infection before treatment were 28% and 192 eggs per gram faeces (epg), respectively. Two years after cure, 22% of the cohort were re-infected, but with a lighter intensity (67 epg). Sixty-four subjects (37%) showed significant improvement in ultrasound parenchyma images after treatment and 51 subjects (54%) showed significant improvement of periportal fibrosis. Left-lobe enlargement also reversed (P < 0.05) and splenomegaly reversed in 6 of 8 cases and developed in only 1. Two years post-treatment a dilated portal vein became less frequent, but the decline was not significant (16% vs 11%, P < 0.05). The serum levels of laminin and collagen IV associated with re-infection and intensity and hyaluronic acid levels correlated with ultrasound findings (P < 0.01). Overall, treatment induced a marked decrease in subclinical hepatosplenic morbidity attributable to S. japonicum although low-intensity re-infection after treatment remained relatively frequent. Stratified analysis and logistic models evaluated potential confounding factors for assessment of treatment effects on hepatic fibrosis. S. japonicum infection and moderate-heavy alcohol intake interacted: improvement in parenchymal morbidity was impeded among drinkers (P < 0.05). Chemotherapy focused on at-risk residents controls prevalent subclinical hepatic fibrosis but re-infection indicates the need for complementary control strategies.

Postnatal depression-myth and reality: maternal depression before and after the birth of a child

BACKGROUND

Much has been written about postnatal depression as a clinical condition. There is some evidence to suggest that a substantial proportion of women who give birth experience a depression in the postnatal period. This paper reports the results of a longitudinal study of the mental health of a large sample of women who were in the early stages of pregnancy at entry to the study.

METHODS

Each participant was assessed for symptoms of depression at the first clinic visit (entry to the study), and reassessed at various intervals--at 3-5 days, at 6 months, and again at 5 years after the birth of the child--using the DSSI-D (Delusions-Symptoms-States Inventory).

RESULTS

Retrospective recall questions indicate that shortly after the birth the majority of women experienced some depressed mood. Of those who experienced depressed mood, the data suggest that the symptoms were not severe, nor did these symptoms generally continue beyond a few weeks. The longitudinal data indicate that levels of depression in our sample are highest either at the first clinic visit or at the 5-year follow-up. Rates of depression at the 6-month follow-up are relatively low by comparison.

CONCLUSION

While most mothers experience periods of depressed mood after the birth of their baby, these periods are generally of short duration and of lesser intensity than a major depression. Mothers appear to experience increasing levels of symptoms of depression as their child grows up. Many of the "cases" of depression experienced at the 5-year follow-up represent a recurrence of a previous experience of depression.

Seasonal abundance of Anopheles farauti (Diptera: Culicidae) sibling species in far north Queensland, Australia

In the Cairns area of far north Queensland, Australia, the seasonal abundance of Anopheles farauti Laveran sibling species was studied at 6 locations, representing 3 habitat types, between August 1995 and September 1997. A total of 45,401 An. farauti s.l. was collected using CO2 + octenol baited CDC light traps, and consisted of 29,565 An. farauti No. 2, 14,214 An. farauti No. 3, and 1,622 An. farauti s.s. The relative abundance of all 3 species differed significantly by season and location. An. farauti No.2 was the dominant species except in Cairns, where An. farauti s.s. was most abundant, and at Ninds Creek, where An. farauti No. 3 predominated. The dominant species at each location was present year round, although peaks in seasonal abundance were observed. An. farauti s.s. populations were highest during the wet season (January-April). In lowland freshwater swamp habitats and 1 brackish location, An. farauti No. 2 was more abundant during the wet season. However, at the highland freshwater swamp habitat, populations of An. farauti No. 2 were highest during the late dry season and early wet season (October-December). There was a significant positive correlation of both temperature and rainfall with An. farauti s.s. and An. farauti No. 2 trap collections. There was a negative correlation between An. farauti No. 3 and temperature, indicating that this species may be more abundant during cool weather. Although there were significant relationships among weather variables and An. farauti s.l. collections, correlation values were generally low, indicating that other factors may contribute to variability among An. farauti sibling species trap collections.

Diet and cancer prevention: the fiber first diet

Diet can play a major role in cancer prevention. The international differences in cancer incidence are largely accounted for by lifestyle practices that include nutrition, exercise, and alcohol and tobacco use. About 50% of cancer incidence and 35% of cancer mortality in the U.S., represented by cancers of the breast, prostate, pancreas, ovary, endometrium, and colon, are associated with Western dietary habits. Cancer of the stomach, currently a major disease in the Far East, relates to distinct, specific nutritional elements such as excessive salt intake. For these cancers, information is available on possible initiating genotoxic factors, promoting elements, and prophylactic agents. In general, the typical diet in the United States contains low levels of the potent carcinogenic agents, heterocyclic amines, formed during the cooking of meats. It provides only about half the potent appropriate fiber intake and is high in calories. About twice as many calories as would be desirable come from fat, certain kinds of which enhance the development of cancers. Other foods with functional properties, such as soy products and tea, can be beneficial. To achieve reduction in risk of certain cancers, diet must be optimized, primarily to reduce caloric intake and the fat component. The latter should be 20% or less of total caloric intake and fiber should be increased to 25-35 g per day for adults. One approach to achieving these goals is the Fiber First Diet, a diet designed around adequate fiber intake from grains, especially cereals, vegetables, legumes, and fruits, which thereby reduces both calorie and fat intake. Such dietary improvements will not only reduce cancer and other chronic disease risks, but will contribute to a healthy life to an advanced age. A corollary benefit is a lower cost of medical care.

Behavioural and cognitive associations of short stature at 5 years

OBJECTIVES

To determine the extent to which childhood short stature is associated with cognitive, behavioural and chronic health problems, and whether these problems could be attributed to recognized adverse biological, psychosocial or psychological factors.

METHODOLOGY

At their first antenatal session, 8556 women were enrolled in a prospective study of pregnancy. When their children were 4 and 6 years of age, mothers completed a detailed questionnaire concerning their child's health and behaviour. A Peabody Picture Vocabulary Test-Revised (PPVT-R) was completed by the child at 5 years of age. Z scores were used to categorize height measurements in 3986 children. The relationship of these height categories with the child's health, and behavioural and cognitive problems was then examined.

RESULTS

No association was found between height and symptoms of chronic disease or behaviour problems in boys or girls. On the unadjusted analysis, mean PPVT-R scores were significantly lower in boys with heights < 3 percentile and 3-< 10 percentile compared with study children between 10 to 90 percentile (P < 0.01). Scores were similarly significantly lower in girls with heights < 3 percentile and 3-10 percentile (P = 0.01). Even after adjusting for psychosocial and biological confounders, short stature remained a significant predictor for lower PPVT-R scores in both boys and girls, although height only accounted for 1.1% of the variance in scores in boys and 0.5% of the variance in PPVT-R scores in girls. Psychosocial factors had a greater role than height in determining PPVT-R scores at 5 years of age.

CONCLUSIONS

These findings suggest a significant, though small, association between height and PPVT-R scores at 5 years of age, independent of psychosocial disadvantage and known biological risk factors.

Results of elective abdominal aortic aneurysm repair in the 1990s: A population-based analysis of 2335 cases

OBJECTIVE

The safety and efficacy of conventional abdominal aortic aneurysm (AAA) repair are undergoing increased examination in parallel with the development of less invasive repair methods. Because most published studies of elective AAA repair report operations performed in tertiary referral institutions and thus may not reflect the outcome in the surgical community at large, the current population-based study was undertaken to document the results obtained across a broad spectrum of clinical practice in a defined geographic area and to examine the factors that influence the outcomes.

METHODS

The Maryland Health Services Cost Review Commission database was used to identify all the elective AAA repairs that were performed in all the nonfederal acute care hospitals in the state from 1990 to 1995.

RESULTS

Elective AAA repair was performed on 2335 patients (mean age, 70.4 years) in 46 of the 52 (88%) nonfederal acute care hospitals in the state, including seven high-volume (>100 cases), nine moderate-volume (50 to 99 cases), and 30 low-volume (<50 cases) institutions. The in-hospital mortality rate was 3.5% and increased significantly with advancing age: less than 65 years, 2.2%; 65 to 69 years, 2.5%; 70 to 79 years, 3.5%; and more than 80 years, 7.3% (P =.002). Mortality rates were higher for women (4.5% vs 3.2%; P =.17), for blacks (6.7% vs 3.2%; P =.046), and for patients with renal failure (11.8% vs 3. 4%; P =.11) but not for patients with hypertension, diabetes, heart disease, and pulmonary disease. The operative mortality rate was inversely correlated with hospital volume (4.3% in low-volume hospitals, 4.2% in moderate-volume hospitals, and 2.5% in high-volume hospitals; P =.08), although no differences were noted in the mean ages or comorbidity levels of patients who underwent operations in these three hospital populations. The operative mortality rate was inversely correlated with the experience of the individual surgeon: one case, 9.9%; two to nine cases, 4.9%; 10 to 49 cases, 2.8%; 50 to 99 cases, 2.9%; and more than 100 cases, 3.8% (P =.01). Multivariate analysis results identified patient age (P =. 002), low hospital volume (P =.039), and very low surgeon volume (P =.01) as independent predictors of operative mortality. The mean length of stay and mean hospital charges were 10.6 days and $17,589 and decreased with increasing surgeon volume: one case, 22.7 days/$32,800; two to nine cases, 10.6 days/$18,509; 10 to 49 cases, 10.0 days/$16,611; 50 to 99 cases, 10.9 days/$17,843; and more than 100 cases, 9.6 days/$16,682 (P <.0001/P <.0001).

CONCLUSION

Elective AAA repair is a safe procedure in contemporary practice in Maryland. Operative risk is increased among the elderly and when operations are performed by surgeons with very low volumes or in low-volume hospitals. Hospital lengths of stay were shorter and charges were lower when elective AAA repair was performed by surgeons with higher volumes.

Thoracoabdominal aneurysm repair

Aneurysms that extend from the descending thoracic aorta into the abdomen and also those that involve the visceral segments of the upper abdominal aorta are traditionally classified as thoracoabdominal. Besides the surgical exposure difficulties associated with repair of these aneurysms, the temporary interruption of renal, splanchnic, and perhaps even spinal cord flow introduces a number of potential complications that makes surgical repair of these aneurysms a daunting task. The exact incidence of thoracoabdominal aneurysms is unknown, but population studies suggest a prevalence at least a log fold less than the more common infrarenal abdominal aortic aneurysm. The poor prognosis of nonsurgically treated aneurysmal disease of the descending thoracic and abdominal aortas has been reasonably well established. Few patients with thoracoabdominal aneurysms survive beyond five years as a result of not only aneurysm rupture but also death from advanced co-morbid medical disease. Since the first successful report of thoracoabdominal aneurysm repair over 40 years ago, a number of remarkable contributions have been made in the field. These advances have led to a significant decline in operative mortality as well as procedure related morbidity. Spinal cord ischemia remains a perplexing and devastating complication following thoracoabdominal aneurysm repair. A number of surgical adjuncts have been developed over the years to reduce the incidence of cord ischemic complications, yet a great deal of controversy still exists with regards to the optimal protective strategy. A description of the incidence, natural history, and classification of thoracoabdominal aneurysms, along with associated repair techniques centered on reducing spinal cord ischemic complications will form the basis for this review.

Diethylnitrosamine exposure-responses for DNA ethylation, hepatocellular proliferation, and initiation of carcinogenesis in rat liver display non-linearities and thresholds

In previous exposure-response studies, we have documented non-linearities for some of the early effects in rat liver of diethylnitrosamine (DEN) and a near no-effect levels for initiation of promotable liver neoplasms at the lowest cumulative exposure of 0. 5 mmol/kg body weight; this in spite of formation of DNA adducts and induction of hepatocellular altered foci (HAF). To extend these investigations, in an initiation segment, young male F344 rats were administered four exposures of DEN ranging from a cumulative total of 0.25 mmol, which is half of the previously used low exposure, up to 2 mmol per kg body weight, an effective initiating exposure. These exposures were achieved by once weekly intragastric instillations of one-tenth the total exposures for up to 10 weeks. The initiation segment was followed by a 4 week recovery segment, to allow for remission of acute and subchronic effects of DEN, after which the groups were maintained on 0.06% phenobarbital in the diet for 24 weeks to promote liver tumor development in order to assess initiation. During and after initiation and at the end of recovery, selected groups were studied for several crucial effects involved in hepatocarcinogenicity. The low exposure produced a low-level of DNA ethylation at both 5 and 10 weeks of exposure, measured as O(4)-ethylthymidine, the most persistent promutagenic ethylation product. At the 5 week interval, the adduct values of the higher exposures were less than proportional to the increment of exposure, suggestive of nonlinearity. Assessment of cellular proliferation by staining for proliferating cell nuclear antigen revealed that the lowest exposure did not increase the replicating fraction of hepatocytes during the initiation (10 weeks) or recovery (4 weeks) segments, whereas in the three higher exposure groups, proliferation was increased in relation to dose and time. Preneoplastic HAF expressing glutathione S-transferase-placental-type were present at low multiplicity in control livers and their multiplicity was increased in all exposure groups by the end of exposure, at which time the increase in the high exposure group was disproportionately greater than the increment of exposure. After phenobarbital administration in the promotion segment, all exposure groups exhibited further HAF increases at 39 weeks. At the end of the promotion segment, no hepatocellular neoplasm was found in 80 controls or in 40 rats in the low exposure group. In the mid-low exposure group, which was the previously studied low exposure, only one adenoma was found, yielding a 3% incidence, while in the two higher exposure groups, 32 and 80% of rats exhibited liver neoplasms, which were increased disproportionately greater than the increments of exposure. Thus, the findings document non-linearities of early DEN effects and at the lowest cumulative dose, a no-effect level (NEL) or threshold for initiation of promotable liver neoplasms. These findings provide a conceptual basis for understanding why low-level exposures to DNA-reactive carcinogens may convey no cancer risk.

Safety assessment of butylated hydroxyanisole and butylated hydroxytoluene as antioxidant food additives

Butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) are widely used antioxidant food additives. They have been extensively studied for potential toxicities. This review details experimental studies of genotoxicity and carcinogenicity which bear on cancer hazard assessment of exposure to humans. We conclude that BHA and BHT pose no cancer hazard and, to the contrary, may be anticarcinogenic at current levels of food additive use.

Different mechanisms for the photoinduced production of oxidative DNA damage by fluoroquinolones differing in photostability

Several fluoroquinolone antibacterial agents exhibit an adverse phototoxic effect in humans and are photo-cocarcinogenic in mice. The UV-induced production of reactive oxygen species plays a role in the toxicity and may be involved in carcinogenicity. Four fluoroquinolones were examined for the ability to photochemically produce oxidative damage in naked DNA. The major structural difference in the fluoroquinolones that would have an effect on their photostability is the functionality at the 8-position. At this position, 1-cyclopropyl-7-(2,8-diazbicyclo[4.3.0]non-8-yl)-6, 8-difluoro-1,4-dihydro-4-oxo-3-quinolinecarboxylic acid (BAY y3118) contains a chlorine atom, lomefloxacin a fluorine atom, ciprofloxacin a proton, and moxifloxacin a methoxy group. The formation of 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodGuo) in calf thymus DNA was assessed by HPLC with electrochemical detection, and strand breaks were measured in pBR322 with agarose gel electrophoresis. The relative photolability of the fluoroquinolones correlated to the extent of production of 8-oxodGuo and strand breaks, with both UVA and UVB irradiation, in the following order: BAY y3118 approximately lomefloxacin > ciprofloxacin > moxifloxacin. Experiments were performed to determine whether the mechanism of damage was due to a type I (radical) or type II (singlet oxygen) pathway. Nitrogen depletion of oxygen resulted in a decrease in the extent of formation of 8-oxodGuo, suggesting that oxygen was involved. The use of selective radical or singlet oxygen inhibitors was inconclusive with respect to which pathway was involved. The use of D(2)O as a solvent, which would extend the lifetime of singlet oxygen, suggested that this species is involved in the formation of 8-oxodGuo by moxifloxacin and ciprofloxacin, but not by lomefloxacin and BAY y3118. Similarly, it was found that singlet oxygen was not involved in strand break formation. Thus, the evidence suggests that fluoroquinolones can photochemically produce DNA damage by both type I and type II mechanisms.

A 2-year prospective study in China provides epidemiological evidence for resistance in humans to re-infection with Schistosoma japonicum

In 1996, 250 people living in the Dongting-Lake region of China were selected for a 2-year study. All had been or were infected with Schistosoma japonicum. All were treated with praziquantel, although eggs of S. japonicum were only detected in stool samples from 75 of the subjects. In 1998, 213 (85.5%) of these subjects, then with a mean (S.D.) age of 40.2 (14.2) years, provided stool samples for final assessment. Forty-nine (23%) of the 213 were found to be re-infected in 1998, with a geometric mean intensity of infection among the infected of 64.5 eggs/g faeces. The rate of re-infection was highest among those aged < 10 years, declining with increasing age, and higher in males than females (27.3% v. 8.3%; P < 0.005). The mean intensity of infection among the infected males was also higher than that among the infected females [72.4 (4.8) v. 17.8 (2.5) eggs/g; P < 0.005]. Water contact by the subjects was estimated from activity diaries, for 141 days over the 2-year study period, and expressed as skin exposure, in m2-min/day. The mean exposure of a group of subjects was calculated by detransforming the mean of the fourth-root-transformed (i.e. normalized) values for the exposures of each subject within the group. Overall, the 213 individuals had a mean exposure of 6.2 m2-min/day. Differences in occupation led to males having much higher mean water exposures than females (9.2 v. 1.1 m2-min/day). As there was an inverse association between age-specific exposure and age-specific re-infection intensity, the marked reduction seen in intensity of re-infection with increasing age is not attributable to decreasing exposure to water. Instead, the results of this 2-year cohort study provide evidence for age-dependent resistance to re-infection with S. japonicum. The 213 subjects who were followed up were classified, according to epidemiological outcome at the end of the study and the data on water contact, as 'susceptible' (N = 49; 23%), 'insusceptible' (N = 29; 13.6%) or of 'uncertain status' (N = 135; 63.4%). Thus, 78 subjects who are potentially informative in terms of immunogenetics were identified. Further investigation of these individuals should help to shed some light on the role of immunogenetic status in human immunity to Schistosoma japonicum.

Production of interleukin-10 by peripheral blood mononuclear cells from residents of a marshland area in China endemic for Schistosoma japonicum

Interleukin-10 (IL-10) cytokine production was assessed using peripheral blood mononuclear cells (PBMC) from 67 individuals living in an area endemic for schistosomiasis japonica in China (Dongting Lake, Hunan Province), and 11 control subjects from a non-endemic part of the same Province. Production of IL-10 was measured following in vitro stimulation of PBMC using whole parasite extract (SWAP) or a panel of recombinant Schistosoma japonicum antigens (22-kDa tegumental membrane-associated antigen, glyceraldehyde-3-phosphate dehydrogenase, paramyosin, 14-kDa fatty acid-binding protein and 28-kDa glutathione S-transferase) which are of recognized interest in the development of protective immunity to schistosomiasis. Significantly, PBMC isolated from the exposed population compared with the non-exposed population produced higher levels of IL-10. There was a trend towards higher mean levels of IL-10 release in putatively resistant (insusceptible) (consistently egg negative but highly exposed) individuals compared with susceptible (egg-positive) subjects from the exposed population. Analysis of individual exposure (the duration of water contact and the percent body surface area in contact with water, expressed as m2 h/day) vs. IL-10 production indicated a weak but consistent and statistically significant inverse correlation, with lower levels of exposure being associated with higher levels of IL-10. These results suggest an association between IL-10 production and resistance to S. japonicum in subjects from this Chinese population exposed to infection.

Maternal cigarette smoking during pregnancy is an independent predictor for symptoms of middle ear disease at five years' postdelivery

Although an increasing body of literature has demonstrated a link between in utero exposure to cigarette smoke and childhood morbidity, the extent to which such exposure is associated with middle ear disease (MED) is less certain. We hypothesized that in utero exposure to cigarette smoke was associated with an increased risk of MED and aimed to calculate the proportion of disease at 5 years' postdelivery attributable to cigarette exposure during pregnancy. Methods. At their first antenatal session, 8556 women were enrolled in a prospective study of pregnancy. Mothers were followed during pregnancy, at birth, at 6 months' and at 5 years' postdelivery and completed a detailed questionnaire aimed at assessing the frequency of acute (<1 month) and subacute (1-3 months) symptoms of MED and ear surgery. The relationship between MED and smoking status during pregnancy was then examined and subsequently adjusted simultaneously for smoking status at other times and for other potentially confounding variables. Results. In the adjusted analyses, acute ear infections were associated with consumption of 1 to 9 cigarettes (OR: 1.6; 95% CI: 1.1-2.5), 10 to 19 cigarettes (OR: 2.6; 95% CI: 1. 6-4.2) and 20+ cigarettes (OR: 3.3; 95% CI: 1.9-5.9) per day at the first clinic visit. For subacute ear infections, an association was present with consumption of 10 to 19 cigarettes (OR: 2.6; 95% CI: 1. 4-5.0) and 20+ cigarettes (OR: 2.8; 95% CI: 1.3-6.0) at the first clinic visit. In utero exposure to 20+ cigarettes per day at the first clinic visit was also associated with an increased risk of ear surgery by 5 years' postdelivery (OR: 2.9; 95% CI: 1.3-6.6). These associations were independent of smoking at 6 months and at 5 years, age and gender of the child, breastfeeding history, maternal age, maternal education, maternal employment at 5 years, marital status at 5 years, socioeconomic status, use of day care, and the number of siblings or children in the household. A population attributable risk percent at 5 years of 39.4% for acute ear infections, 37.9% for subacute ear infections, and 30.0% for previous ear surgery was found for in utero exposure to cigarette smoke at the first clinic visit. Conclusions. Smoking at the first clinic visit was associated with an increased risk of MED and ear surgery at 5 years of age. The frequency of maternal smoking in the general population gives rise to a high population attributable risk percent for MED. Therefore, it is a significant contributor to childhood morbidity and provides another reason why women should be encouraged to avoid smoking during pregnancy.

Pentachlorophenol (PCP) produces liver oxidative stress and promotes but does not initiate hepatocarcinogenesis in B6C3F1 mice

To elucidate the mechanism of hepatocarcinogenesis of pentachlorophenol (PCP) in mice, critical effects related to carcinogenicity were studied in the livers of B6C3F1 male mice administered PCP at concentrations of 600 and 1200 p.p.m. in the diet for 8 weeks. Oxidative stress was assessed by measurements of 8-oxodeoxyguanosine (8-oxodG) in the liver nuclear DNA and hepatocyte cell proliferation was quantified by bromodeoxyuridine incorporation. Also, initiation and promotion were assessed in a two-stage hepatocarcinogenesis model in which one group of mice was given PCP at concentrations of 600 and 1200 p.p.m. as initiator for the first 13 weeks with subsequent administration of phenobarbital (PB) as promoter at a concentration of 500 p.p.m. in the drinking water for 29 weeks. A second group was initiated with diethylnitrosamine (DEN) at 20 p.p.m. in the drinking water for the first 13 weeks followed after a 4 week recovery interval by PCP at concentrations of 300 and 600 p.p.m. in the diet for 25 weeks. Significant elevations in 8-oxodG levels and cell proliferation were observed in a dose-dependent manner. Incidences and multiplicities of hepatocellular tumors in mice treated with PCP after DEN initiation were increased compared with those in mice given initiation only. In contrast, in mice given PCP as initiator followed by PB no enhancement of neoplastic lesions occurred. These findings are interpreted to demonstrate that PCP exerts a promoting action, but not an initiating effect on liver carcinogenesis and that the promoting action is related to oxidative stress and compensatory hepatocellular proliferation.

Olfaction and symptoms in the multiple chemical sensitivities syndrome

Whereas most idiosyncratic environmental sensitivity complaints do not fit known diagnoses, the multiple chemical sensitivities syndrome (MCS) is an extreme presentation that has defined diagnostic criteria. MCS symptomatics claim that they acquired a sensitized state as the result of a chemical exposure, usually to a solvent or pesticide, but not to a fragrance. Before this exposure, they did not experience symptoms. Following sensitization, symptoms increasing in number and severity with time are attributed by the MCS symptomatic to various exposures that are innocuous to most individuals. Although phenomenological studies have provided no evidence that particular odors elicit MCS symptoms, low levels of fragrances and perfumes are frequently associated with the reporting of MCS symptoms. This evaluation examines proposed mechanisms by which odorants and fragrances might cause either sensitization or elicitation of MCS symptoms, including altered odor sensitivity, primary irritancy or irritancy-induced upper airway reactivity, neurogenic switching of trigeminal irritancy signals, time-dependent sensitization and limbic kindling, CNS toxicity, and various psychiatric conditions. In no case was there persuasive evidence that any olfactory mechanism involving fragrance underlies either induction of a sensitized state or the triggering of MCS symptoms. Fragrances and other odorants could, however, be associated with symptoms as claimed by MCS symptomatics, because they are recognizable stimuli, but fragrance has not been demonstrated to be causal in the usual sense.

How does domestic violence affect women's mental health?

In this paper we compare the mental health of women who reported domestic violence and women who reported no abuse in their lifetime. A longitudinal study was conducted with women, 16 to 74 years (n = 358), who attended the emergency department of a major public hospital in Australia. Our aim was to investigate the nature of symptoms and pattern of mental illness associated with domestic violence. The results of the baseline data reported in this paper showed that women who experienced abuse as adults suffered more ill-effects to their mental health than women who did not experience such abuse; also that women who experienced both adult and child abuse suffered more ill-effects than women who experienced abuse either as an adult or child.

The impact of domestic violence on women's mental health

This longitudinal study aimed to establish a firmer scientific basis for recognition and treatment of post-traumatic psychiatric morbidity associated with domestic violence. The study used a sample of 335 women (mean age 45.5 years) recruited from the Royal Brisbane Hospital Emergency Department. This paper reports baseline data. The outcome measures of lifetime psychiatric diagnoses (DSM-111-R classification), showed that women who reported lifetime adult intimate abuse (n = 162) received significantly more diagnoses of generalised anxiety, dysthymia, depression, phobias, current harmful alcohol consumption and psychoactive drug dependence than those who reported no abuse ever (n = 173). Of the 191 women tested for lifetime post-traumatic stress disorder, those who reported lifetime abuse (n = 115) received significantly more diagnoses than those who reported no abuse (n = 76). Crude prevalence rates of psychiatric diagnoses for women who reported double abuse as child and adult were significantly higher than for women who reported adult intimate abuse only. Adjusted rates showed that doubly abused women had significantly greater risk of current harmful alcohol consumption and lifetime drug dependence than women who reported adult abuse only. A significant independent factor for lifetime psychiatric diagnoses was reporting abuse between a woman's parents. Measurement of the population attributable risk found that one-third of the psychiatric diagnoses were attributable to domestic violence.