Kinetics of Cadmium Uptake and Subcellular Partitioning in the Earthworm <Emphasis Type="Italic">Eisenia fetida</Emphasis> Exposed to Cadmium-Contaminated Soil

To understand the bioaccumulation kinetics of cadmium (Cd) at the subcellular level, toxicokinetics and subcellular fractionation of Cd were determined for the terrestrial earthworm Eisenia fetida exposed to Cd-contaminated red soil. The bioaccumulation factor was 1.74 after exposure to soil containing 1 mg Cd/kg dry weight for 21 days. Four distinct compartments with different Cd-binding affinities were obtained by sequential centrifugations, including the cytosolic fraction (G), the organelles fraction (F), the granular fraction (D), and the tissue, cell membrane, and intact cell fraction (E). Most of the accumulated Cd in the organisms existed as fraction G. Cd bound to the tissue and cell membrane fraction (E) was <8% of total Cd. Only approximately 3% of Cd existed in fraction F, and <1% was found in fraction D. Accumulation and elimination kinetics of Cd in different fractions were accurately described by one-compartment models, and kinetic parameters (uptake rate constant k ₁ and elimination rate constant k ₂ ) were derived. Fractions G and F were responsible for the linear accumulation pattern during 3 weeks of exposure, whereas fractions D and E showed a nonlinear uptake curve, and steady state was achieved after 7 and 14 days of exposure, respectively.     

The development of behavioral and endocrine abnormalities in rats after repeated exposure to direct and indirect stress

The present study compared the effects of direct and indirect stress on the behavior and hypothalamic-pituitary-adrenal axis of rats. Animals were placed in a two compartment box. In one compartment the direct stressed rat was subjected to electric foot shocks randomly applied for 10 minutes (0.5 mA of 1 s duration). In the adjacent compartment, the indirect stressed rats witnessed the application of these electric foot shocks. Our data showed substantial behavioral changes in the open field test, but limited effects in the elevated plus maze. The findings suggested that single and repeated stress exposure may have different consequences, that the effects of stress exposure may develop over time and persist for an extended period, and that both direct and indirect stressed rats displayed a hyposensitive HPA axis following acute restraint stress. Overall our observations moderately indicate direct exposure to elicit behavioral changes, and both direct and indirect exposure to stress to result in aberrations within the neuroendocrine system. With additional development our stress models may be considered for studying the complex interrelationship between an external stressor, and the experience of the organism.     

Acquired jejunoileal diverticulosis and its complications: a review of the literature

Jejunoileal diverticulosis is a rare entity. Jejunoileal diverticulosis is not a disease that surgeons see often in clinical practice; however, it should remain on the differential diagnosis for any patient with an acute abdomen or gastrointestinal bleeding of unknown origin. It can present with a wide range of clinical scenarios and when patients experience chronic symptoms such as bloating, abdominal pain, nausea, bacterial overgrowth, or malabsorption, medical therapy is successful in most patients. However, when patients present with acute symptoms of bleeding, inflammation, perforation, or obstruction, surgical resection and primary anastomosis is often the treatment of choice. If patients are asymptomatic, they are better left alone, even when discovered incidentally in the operating room. In closing, the possibility of a patient having jejunal diverticular disease should be suspected whenever the symptoms of obscure abdominal pain, anemia, dilated jejunal loops on abdominal radiographs, a history of colonic diverticuli, and a history of acute appendicitis.     

The abalone egg vitelline envelope receptor for sperm lysin is a giant multivalent molecule

Abalone sperm lysin is a 16-kDa acrosomal protein, which nonenzymatically and species selectively creates a hole in the egg vitelline envelope (VE) through which the sperm passes to reach the egg cell membrane. The crystal structures of both monomeric and dimeric lysins have been solved and the sequences of lysins from 20 abalone species have been determined. As a first step in understanding the molecular mechanism by which lysin creates a hole in the VE, its VE receptor was isolated. The VE receptor for lysin (VERL) is an unbranched, rod-like molecule with an approximate relative molecular mass of 2 million; half the mass being carbohydrate. Fluorescence polarization studies showed positive cooperativity in the binding of lysin to VERL (EC₅₀ ≈9 nM) and were consistent with the species selectivity of lysin in dissolving VEs. Each molecule of VERL bound between 126 and 142 molecules of monomeric lysin (two independent assays), showing that VERL possesses repetitive lysin-binding motifs.     

利用微波辅助萃取、电感耦合等离子体质谱和离子色谱联用方法测定生物和环境样品中的重金属以评价其对人体健康的潜在危害

【目的】测定生物和环境样品中的重金属及其化学形态，从而更准确地评价其对人体健康的潜在危害，并且监测重金属从环境基质到人体的迁移途径。【方法】利用微波辅助萃取进行样品预处理，离子色谱分离重金属不同化学形态，电感耦合等离子体质谱进行检测。【结果】微波辅助萃取能够将重金属的不同无机和有机形态从样品基质中有效分离，分离过程中金属形态不发生变化。将离子色谱和电感耦合等离子体质谱在线联用，辅以稳定性同位素标记，可以准确测定生物和环境样品中的金属(铅、铬和汞)形态。【结论】提高生物和环境样品中重金属检测的灵敏度，并且测定金属的化学形态，可以对评价重金属对人体健康的潜在危害提供重要信息。     

Associations Between Latent Classes of Interpersonal Polyvictimization and Polyperpetration and Sexual Risk Behaviors Among Young Pregnant Couples: A Dyadic Analysis

Interpersonal violence victimization and perpetration have been associated with sexual risk behaviors among adolescents and young adults, but research is lacking on: (1) how patterns of interpersonal polyvictimization and polyperpetration are associated with sexual risk among young pregnant couples, and (2) how individual and partner experiences of violence differentially impact sexual risk. The current analyses used baseline data from a longitudinal study that followed 296 pregnant young couples from pregnancy to 12 months postpartum. Couples were recruited at obstetrics and gynecology clinics, and an ultrasound clinic in the U.S. Latent class analysis identified subgroups based on polyvictimization and polyperpetration. Using the Actor–Partner Interdependence Model, path analyses assessed actor–partner effects of class membership on sexual risk. Three latent classes were used for women: Class 1: Polyvictim–Polyperpetrator; Class 2: Nonvictim–Nonperpetrator; and Class 3: Community and Prior IPV Victim. Four latent classes were used for men: Class 1: Community and Prior IPV Victim; Class 2: Polyvictim–Nonpartner Perpetrator; Class 3: Prior IPV and Peer Victim; and Class 4: Nonvictim–Nonperpetrator. Path analyses revealed that females in Class 2 and their male partners had higher condom use than females in Class 3. Males in Class 2 had more sexual partners than males in Class 1. Among nonmonogamous couples, males in Class 2 were less likely to be involved with a female partner reporting unprotected sex than males in Class 1. Among nonmonogamous couples, females in Class 2 had more acts of unprotected sex than females in Class 1. Males in Class 4 were less likely to have concurrent sexual partners compared to males in Class 1. Risk reduction interventions should address both victimization and perpetration. Additional research is needed to understand how mechanisms driving differential sexual risk by patterns of interpersonal polyvictimization and polyperpetration.     

Medical oophorectomy with and without estrogen add-back therapy in the prevention of migraine headache

OBJECTIVES: To determine the preventive benefit of "medical oophorectomy" and transdermal estradiol in women with migraine. BACKGROUND: Epidemiological studies have demonstrated that declines in serum estrogen levels occurring during normal menstrual cycles can trigger headache in women with migraine. Prior to this study, no randomized controlled trials have evaluated whether minimizing these hormonal changes pharmacologically can prevent headache. METHODS: Twenty-one women with regular menstrual cycles and a diagnosis of migraine headache were enrolled. After a 2.5-month placebo run-in phase, all patients received a subcutaneous goserelin implant (a gonadotropin-releasing hormone agonist) to induce a medical oophorectomy. One month later, while continuing goserelin, participants were randomized to receive a transdermal patch containing 100 microg of estradiol-17beta (gonadotropin-releasing hormone agonist/estradiol group, n = 9) or a placebo patch (gonadotropin-releasing hormone agonist/placebo group, n = 12) during a 2-month treatment phase. The primary outcome measure was the headache index, which was defined as the mean of pain severity ratings (0 to 10 scale) recorded three times per day by daily diary. Secondary outcome measures included headache disability, headache severity, headache frequency, and the percentage of headaches with a pain severity rating of 7 or greater. RESULTS: The headache index was significantly lower during the treatment period in the gonadotropin-releasing hormone agonist/estradiol group than in the gonadotropin-releasing hormone agonist/placebo group (P =.025). Similar improvements were observed in the gonadotropin-releasing hormone agonist/estradiol group for all secondary outcome measures with the exception of headache frequency, which was unchanged between the groups. Within the gonadotropin-releasing hormone agonist/estradiol group, there was a 33.7% reduction (95% confidence interval, -64.4 to -3.0) in the headache index during the treatment phase when compared with the placebo run-in phase; no difference was seen between those phases within the gonadotropin-releasing hormone agonist/placebo group. CONCLUSIONS: Minimization of hormonal fluctuations with gonadotropin-releasing hormone agonist therapy alone is inadequate to prevent headache in women who are premenopausal with migraine. The addition of transdermal estradiol to existing gonadotropin-releasing hormone agonist therapy provides a modest preventive benefit.