Age- and Sex-Related Variation in Sensitivity to the Pyrethroid Cypermethrin in the Marine Copepod Acartia tonsa Dana

Acute effects of cypermethrin, a pesticide used to treat ectoparasite infestations of salmon, were assessed using the calanoid copepod Acartia tonsa. A. tonsa has been widely used for hazard assessment of chemicals in the marine environment using acute toxicity tests, but only with randomly selected adults, assuming a sex ratio of 1:1. The present study assesses the environmental hazard of cypermethrin by exposing nauplii and adult males and females, separately. Our results showed that the naupliar stages were 28 times more sensitive to cypermethrin than adults after 96 h of exposure, with LC₅₀s of 0.005 μg L⁻¹ and 0.142 μg L⁻¹, respectively. Significant differences in sensitivity between sexes were only found during the first 24 h of exposure, with males being approximately twice as sensitive as females. The results of age-related variation in sensitivity are supported by studies with other species of copepods and toxicants, where the increased capacity of the adults for detoxification, the allometric differences in weight and size, and the molting process are given as explanations. Variation in sensitivity between sexes is discussed in terms of faster depuration rates in females through egg production and implications of feeding rate changes after 24 h of exposure. Our results suggested that standard toxicity test methods using A. tonsa are unsatisfactory because the most sensitive life stage is not included and sex-related differences in tolerance are not taken into account. We also found that cypermethrin caused significant mortality in Acartia at exposures concentrations from one to three orders of magnitudes lower than the recommended field treatment concentration for copepodic infestations. Received: 27 April 2001/Accepted: 1 July 2001     

The detection of intracytoplasmic interleukin-1 alpha, interleukin-1 beta and tumour necrosis factor alpha expression in human monocytes using two colour immunofluorescence flow cytometry.

Two colour flow cytometry was used to analyse in situ cytokine expression by human monocytes. Whole blood was cultured in siliconised glass bottles, with or without E. coli lipopolysaccharide (LPS), for various times, and the mononuclear cells (MNCs) then exposed to a variety of permeabilisation procedures prior to flow cytometric analysis. Paraformaldehyde (PF)/saponin fixation preserved cellular morphology, and caused a reproducible degree of permeabilisation (estimated by propidium iodide inclusion: mean 94%, range 86-99% (n = 33)). After fixation with 4% PF and permeabilisation with 1% saponin at 0 degrees C in PBS containing 20% human serum, MNCs were incubated with phycoerythrin(PE)-conjugated mouse anti-CD14 (monocyte phenotype) and polyclonal rabbit anti-human interleukin-1 alpha (IL-1 alpha), IL-1 beta, tumour necrosis factor alpha (TNF-alpha), or control rabbit IgG. Binding of rabbit antibodies was detected using goat anti-rabbit IgG fluorescein isothiocyanate (FITC). FITC fluorescence was increased in CD14 PE positive cells with the three anti-cytokine antibodies following LPS stimulation, compared with controls. There was a reproducible dose related response in monocyte IL-1 beta and TNF-alpha expression following LPS stimulation, with early peaks in TNF-alpha (2 h), compared with IL-1 beta (4 h), and IL-1 alpha (12 h). Specificity of this cytokine detection system was confirmed by inhibition studies using the corresponding recombinant human cytokines, by an absence of staining in CD14 negative or unpermeabilised MNCs, and by the characteristic cytoplasmic localisation of the different cytokines visualised with UV immunochemistry. Hence, the methods described here provide a reproducible, semiquantitative and specific assay for the detection of cell associated monokines. The technique may be applicable to the analysis of a variety of different cytokines in other phenotypically defined cell populations.     

Expression of superoxide dismutase and xanthine oxidase in myometrium, fetal membranes and placenta during normal human pregnancy and parturition

Superoxide, an agent which attenuates the half-life of nitric oxide, is metabolized and synthesized by superoxide dismutase (SOD) and xanthine oxidase, respectively. Over the last few years much work has focused on the role of nitric oxide in human parturition. The aim of this study was to determine whether the onset of human parturition is associated with a change in the expression of copper/zinc superoxide dismutase (Cu/Zn SOD), manganese superoxide dismutase (Mn SOD) or xanthine oxidase within the uterus. Samples of myometrium, placenta, decidua and fetal membranes were obtained from women before and after the onset of labour at term. Immunocytochemistry was used to localize Cu/Zn SOD, Mn SOD and xanthine oxidase and measure SOD enzyme activity. Cu/Zn and Mn SOD-like immunoreactivity was detected in syncytiotrophoblast cells, villous stromal cells and endothelial cells of blood vessels in the placenta. In the myometrium Cu/Zn and Mn SOD were localized to myocytes and endothelial cells and to some vascular smooth muscle cells. In the fetal membranes we observed staining for Cu/Zn SOD and Mn SOD in the amnion, chorion, extravillous trophoblast and decidua. There was no difference in SOD enzyme activity or staining intensity for SOD between different cell types before and during labour. Xanthine oxidase immunoreactivity was identified in each of the tissues examined and again there was no difference in immunostaining in tissues obtained from women delivered before or after the onset of labour. These results show that the pregnant uterus is capable of both synthesizing and degrading superoxide and suggest that superoxide dismutase and xanthine oxidase may play a role in the maintenance of uterine quiescence during pregnancy, but not in the initiation of parturition.      

Metastatic breast carcinoma with appearance resembling micropapillary ductal carcinoma in situ.

AIM--To investigate tumour in an axillary lymph node resembling micropapillary ductal carcinoma in situ. METHODS--Sections of tumour in the breast and axillary lymph node were stained with haematoxylin and eosin, and immunohistochemically with antibodies to basement membrane and myoepithelial cells. RESULTS--Tumour in both the breast and axillary lymph node contained areas resembling micropapillary ductal carcinoma in situ. Surrounding these islands, there was a band of eosinophilic material resembling basement membrane and spindle cells that in places appeared to lie outside the basement membrane. Micropapillary tumour at both sites showed weak and discontinuous staining for collagen IV and laminin. The spindle cells stained for alpha-smooth muscle actin, but not for S100. By contrast, immunohistochemistry showed complete rings of basement membrane and myoepithelial cells around definite ductal carcinoma in situ and normal breast lobules and ducts. CONCLUSIONS--Invasive primary and metastatic carcinoma of the breast can have a growth pattern resembling micropapillary ductal carcinoma in situ.     

Personality profiles of pilots

Samples of Air Force fighter pilots, trainee commercial pilots, and males drawn from the general community completed the Edwards Personality Preference Schedule (EPPS). Four significant effects were found for individual sub-scales; three (Achievement, Affiliation, and Nurturance) identifying air force fighter pilots. Commercial pilot trainees scored significantly less than the community sample on Succorance and Nurturance. The data suggest that the EPPS consists of several related personality dimensions. One of these, "sociability," discriminated fighter pilots from the general community.     

Rubidium-86 uptake by red blood cells of breast cancer patients

The red blood cell (RBC) uptake of rubidium-86 (Rb-86), a sensitive in vitro test of RBC membrane transport, was measured in 22 controls, 8 patients with benign breast lesions, and 30 stage I/II, 13 stage III/IV untreated breast cancers. Total Rb-86 transport was measured. Following ouabain block, passive transport was determined, allowing calculation of active Rb-86 uptake by difference. There was a significant decrease in total and passive uptake by RBCs from patients with breast cancer when compared to controls and those with benign lesions (total uptake 58.6 ± 6.1% versus 63.6 ± 3.9%, P < 0.01; passive uptake 38.7 ± 6.8% versus 42.7 ± 4.6%, P < 0.02). The Rb-86 uptake returned towards normal in successfully treated stages-II-to-IV patients. There were no correlations with the patient's age, hematocrit, or incubation hematocrit with RBC Rb-86 uptakes. Results from incubation in Krebs-Ringer solution were not consistent with a plasma blocking factor. The RBC potassium content was slightly increased in the cancer patients. This, along with decreased passive transport, eliminates the nonspecific malfunction of the Na-K-pump as an explanation, and suggests that the decreased uptake is a cancer-related phenomenon.     

Duplex Doppler ultrasound of the hepatic artery in patients with acute alcoholic hepatitis

BACKGROUND: Acute alcoholic hepatitis (AAH) is a clinical diagnosis associated with increased hepatic artery diameter and flow. Duplex Doppler ultrasound (DDU) has been shown to accurately measure arterial flow in both liver and kidney transplant patients. The authors conducted a blinded, controlled study to evaluate the accuracy of measuring hepatic artery parameters with DDU in diagnosing AAH. STUDY: Duplex Doppler ultrasound was performed by an investigator, blinded to group makeup, on 22 consecutive hospital inpatients with the clinical diagnosis of AAH. The diagnosis of AAH was based on specific criteria, including the following: recent alcohol abuse, hyperbilirubinemia, prolonged prothrombin time, leukocytosis, hepatomegaly, hepatic bruit, and marked redistribution of isotope on 99mTc-sulfur colloid liver-spleen scan. Controls were 12 cirrhotic patients without AAH and 17 healthy volunteers. Duplex Doppler ultrasound measurements were obtained most consistently from the proximal right hepatic artery. Measured parameters included the following: peak systolic velocity (PSV); resistive index = (PSV - end diastolic velocity [EDV])/PSV; pulsatility index = (PSV - EDV)/mean velocity; and hepatic artery diameter. RESULTS: The mean hepatic artery diameter was significantly larger in patients with AAH (3.55 +/- 0.72 mm) than in patients with cirrhosis (2.75 +/- 0.69 mm; p = 0.003) and healthy controls (2.68 +/- 0.69 mm; p = 0.001). The mean PSV was significantly higher in patients with AAH (187 +/- 52 cm/s) compared with cirrhotic (67 +/- 51 cm/s) and healthy (66 +/- 51 cm/s) controls (p = 0.0001). The mean resistive index was lower in AAH patients (0.60 +/- 0.11) compared with cirrhotic (0.69 +/- 0.10; p value was not significant) and healthy controls (0.72 +/- 0.11; p = 0.004). The mean pulsatility index was lower in AAH patients (1.04 +/- 0.47) compared with cirrhotic (1.36 +/- 0.45; p value was not significant) and healthy controls (1.53 +/- 0.45; p = 0.01). CONCLUSIONS: In the appropriate clinical setting, an elevated hepatic artery diameter or PSV measurement is suggestive of AAH. Duplex Doppler ultrasound offers a noninvasive test to assist in the diagnosis of AAH.