Paralytic shellfish poisoning (PSP) toxin binders for optical biosensor technology: problems and possibilities for the future: a review

This review examines the developments in optical biosensor technology, which uses the phenomenon of surface plasmon resonance, for the detection of paralytic shellfish poisoning (PSP) toxins. Optical biosensor technology measures the competitive biomolecular interaction of a specific biological recognition element or binder with a target toxin immobilised onto a sensor chip surface against toxin in a sample. Different binders such as receptors and antibodies previously employed in functional and immunological assays have been assessed. Highlighted are the difficulties in detecting this range of low molecular weight toxins, with analogues differing at four chemical substitution sites, using a single binder. The complications that arise with the toxicity factors of each toxin relative to the parent compound, saxitoxin, for the measurement of total toxicity relative to the mouse bioassay are also considered. For antibodies, the cross-reactivity profile does not always correlate to toxic potency, but rather to the toxin structure to which it was produced. Restrictions and availability of the toxins makes alternative chemical strategies for the synthesis of protein conjugate derivatives for antibody production a difficult task. However, when two antibodies with different cross-reactivity profiles are employed, with a toxin chip surface generic to both antibodies, it was demonstrated that the cross-reactivity profile of each could be combined into a single-assay format. Difficulties with receptors for optical biosensor analysis of low molecular weight compounds are discussed, as are the potential of alternative non-antibody-based binders for future assay development in this area.

Tangentially migrating transient glutamatergic neurons control neurogenesis and maintenance of cerebral cortical progenitor pools

The relative contribution of intrinsic and extrinsic cues in the regulation of cortical neurogenesis remains a crucial challenge in developmental neurobiology. We previously reported that a transient population of glutamatergic neurons, the cortical plate (CP) transient neurons, migrates from the ventral pallium (VP) over long distances and participate in neocortical development. Here, we show that the genetic ablation of this population leads to a reduction in the number of cortical neurons especially fated to superficial layers. These defects result from precocious neurogenesis followed by a depletion of the progenitor pools. Notably, these changes progress from caudolateral to rostrodorsal pallial territories between E12.5 and E14.5 along the expected trajectory of the ablated cells. Conversely, we describe enhanced proliferation resulting in an increase in the number of cortical neurons in the Gsx2 mutants which present an expansion of the VP and a higher number of CP transient neurons migrating into the pallium. Our findings indicate that these neurons act to maintain the proliferative state of neocortical progenitors and delay differentiation during their migration from extraneocortical regions and, thus, participate in the extrinsic control of cortical neuronal numbers.

Glomerular filtration rate following pediatric liver transplantation--the SPLIT experience

Impaired kidney function is a well-recognized complication following liver transplantation (LT). Studies of this complication in children have been limited by small numbers and insensitive outcome measures. Our aim was to define the prevalence of, and identify risk factors for, post-LT kidney dysfunction in a multicenter pediatric cohort using measured glomerular filtration rate (mGFR). We conducted a cross-sectional study of 397 patients enrolled in the Studies in Pediatric Liver Transplantation (SPLIT) registry, using mGFR < 90 mL/min/1.73 m(2) as the primary outcome measure. Median age at LT was 2.2 years. Primary diagnoses were biliary atresia (44.6%), fulminant liver failure (9.8%), metabolic liver disease (16.4%), chronic cholestatic liver disease (13.1%), cryptogenic cirrhosis (4.3%) and other (11.8%). At a mean of 5.2 years post-LT, 17.6% of patients had a mGFR < 90 mL/min/1.73 m(2) . In univariate analysis, factors associated with this outcome were transplant center, age at LT, primary diagnosis, calculated GFR (cGFR) at LT and 12 months post-LT, primary immunosuppression, early post-LT kidney complications, age at mGFR, height and weight Z-scores at 12 months post-LT. In multivariate analysis, independent variables associated with a mGFR <90 mL/min/1.73 m(2) were primary immunosuppression, age at LT, cGFR at LT and height Z-score at 12 months post-LT.

Development of ELISAs for detecting domoic acid, okadaic acid, and saxitoxin and their applicability for the detection of marine toxins in samples collected in Belgium

Okadaic acid, a diarrhetic shellfish poison, domoic acid, an amnesic shellfish poison, and saxitoxin, a paralytic shellfish poison, are three of the best-known marine biotoxins. The mouse bioassay is the method most widely used to detect many of these toxins in shellfish samples, but animal welfare concerns have prompted researchers to seek alternative methods of detection. In this study, three direct competitive enzyme-linked immunosorbent assays (ELISAs), each based on antibodies raised in rabbits against a conjugate of the analyte of interest, were developed for marine biotoxin detection in mussel, oyster, and scallop. One assay was for okadaic acid, one for saxitoxin, and one for domoic acid usually detected and quantified by high-performance liquid chromatography-ultraviolet light (HPLC-UV). All three compounds and a number of related toxins were extracted quickly and simply from the shellfish matrices with a 9 : 1 mixture of ethanol and water before analysis. The detection capabilities (CCbeta values) of the developed ELISAs were 150 microg kg(-1) for okadaic acid, 50 microg kg(-1) for domoic acid, and 5 microg kg(-1) or less for saxitoxin. The assays proved satisfactory when used over a 4-month period for the analysis of 110 real samples collected in Belgium.

Exercise interventions for upper-limb dysfunction due to breast cancer treatment

BACKGROUND

Upper-limb dysfunction is a commonly reported side effect of treatment for breast cancer and may include decreased shoulder range of motion (the range through which a joint can be moved) (ROM) and strength, pain and lymphedema.

OBJECTIVES

To review randomized controlled trials (RCTs) evaluating the effectiveness of exercise interventions in preventing, minimi sing, or improving upper-limb dysfunction due to breast cancer treatment.

SEARCH STRATEGY

We searched the Specialised Register of the Cochrane Breast Cancer Group, MEDLINE, EMBASE, CINAHL, and LILACS (to August 2008); contacted experts, handsearched reference lists, conference proceedings, clinical practice guidelines and other unpublished literature sources.

SELECTION CRITERIA

RCTs evaluating the effectiveness and safety of exercise for upper-limb dysfunction.

DATA COLLECTION AND ANALYSIS

Two authors independently performed the data abstraction. Investigators were contacted for missing data.

MAIN RESULTS

We included 24 studies involving 2132 participants. Ten of the 24 were considered of adequate methodological quality.Ten studies examined the effect of early versus delayed implementation of post-operative exercise. Implementing early exercise was more effective than delayed exercise in the short term recovery of shoulder flexion ROM (Weighted Mean Difference (WMD): 10.6 degrees; 95% Confidence Interval (CI): 4.51 to 16.6); however, early exercise also resulted in a statistically significant increase in wound drainage volume (Standardized Mean Difference (SMD) 0.31; 95% CI: 0.13 to 0.49) and duration (WMD: 1.15 days; 95% CI: 0.65 to 1.65).Fourteen studies examined the effect of structured exercise compared to usual care/comparison. Of these, six were post-operative, three during adjuvant treatment and five following cancer treatment. Structured exercise programs in the post-operative period significantly improved shoulder flexion ROM in the short-term (WMD: 12.92 degrees; 95% CI: 0.69 to 25.16). Physical therapy treatment yielded additional benefit for shoulder function post-intervention (SMD: 0.77; 95% CI: 0.33 to 1.21) and at six-month follow-up (SMD: 0.75; 95% CI: 0.32 to 1.19). There was no evidence of increased risk of lymphedema from exercise at any time point.

AUTHORS' CONCLUSIONS

Exercise can result in a significant and clinically meaningful improvement in shoulder ROM in women with breast cancer. In the post-operative period, consideration should be given to early implementation of exercises, although this approach may need to be carefully weighed against the potential for increases in wound drainage volume and duration. High quality research studies that closely monitor exercise prescription factors (e.g. intensity), and address persistent upper-limb dysfunction are needed.

Identifying Symptom Clusters in Breast Cancer: Implications on Patient Quality of Life

Background: Patients undergoing treatment for advanced cancer often experience multiple symptoms. These symptoms occur with varying frequency, intensity, and impact. Pain, fatigue, insomnia, anorexia and dyspnea are consistently among the 10 most prevalent symptoms associated with cancer and its treatment. We conducted a multivariate analysis to investigate the impact of cancer symptoms on patient quality of life (QoL) in breast cancer.Material and Methods: A consecutive series of 226 breast cancer patients treated at the Cancer Treatment Centers of America at Southwestern Regional Medical Center between Jan 2001 and Nov 2006. Cancer symptoms were assessed using the symptom subscales of European Organization for Research Treatment of Cancer - Quality of Life Questionnaire (QLQ-C30). Symptom scores range from 0-100 with lower scores indicating better while higher scores indicating worse symptoms. QoL was assessed using Ferrans and Powers Quality of Life Index (QLI). QLI measures overall QoL and QoL in 4 major subscales: health/physical, social/economic, psychological/spiritual, and family. QLI scores range from 0-30 with higher scores indicating better QoL. The relationship between QLQ-C30 symptoms and QLI was evaluated using multivariate linear regression.Results: Of 226 patients, 98 were newly diagnosed while 128 had failed prior treatment before coming to our hospital. The mean age was 52.5 years (range = 27-82 years). We found that every 10 unit increase in fatigue (p=.004) and pain (p=.001) was significantly associated with 0.65 and 0.66 unit decline in QLI health/physical subscale after controlling for age, treatment history, stage at diagnosis and other cancer symptoms. Similarly, every 10 unit increase in insomnia (p=.02) was significantly associated with 0.35 unit decline in QLI family subscale. Finally, every 10 unit increase in pain (p=.01) and insomnia (p=.03) was significantly associated with 0.34 and 0.21 unit decline in overall QoL.Discussion: We found fatigue, pain and insomnia to be independent predictors of QoL after controlling for each other, age, treatment history and stage at diagnosis. Recognition and timely treatment of symptom clusters could result in improved QoL in patients with breast cancer.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 5043.

Adenovirus 36 seropositivity is strongly associated with race and gender, but not obesity, among US military personnel

BACKGROUND

Although several studies have shown a positive association between evidence of anti-adenovirus 36 (Ad-36) antibodies (Ad-36 exposure) and (1) obesity and (2) serum cholesterol in animals, there is limited research demonstrating this association in humans. There is also limited research on transmission, presentation and demographics of Ad-36 infection.

DESIGN

(1) Body mass (body mass index (BMI)), (2) fasting serum cholesterol and triglyceride levels and (3) demographic characteristics were compared between Ad-36 seropositive and seronegative groups. The majority of subjects were matched as cases versus controls on a number of demographic variables.

SUBJECTS

A total of 150 obese and 150 lean active-duty military personnel were studied.

MEASUREMENTS

Subjects completed a questionnaire regarding demographic and behavioral characteristics. Subject serum samples were tested by serum neutralization assay for the presence of anti-Ad-36 antibodies.

RESULTS

In all, 34% of obese and 39% of lean subjects had Ad-36 exposure, an insignificant difference. Serum cholesterol and triglyceride levels were significantly higher among the obese subjects than among the lean, but there were no associations between serum cholesterol and triglyceride levels and Ad-36 exposure. Positive associations were found between Ad-36 exposure and age, race and gender.

CONCLUSION

The study stands in contrast to previous work that has shown a positive relationship between Ad-36 exposure and (1) obesity, and (2) levels of serum cholesterol and triglycerides. In this study there was no association in either case. Unanticipated relationships between Ad-36 exposure and age, race and gender were found, and this is the first time that such a link between Ad-36 exposure and demographics has been found.

Mitochondrial function and redox state in mammalian embryos

Mitochondria play a central and multifaceted role in the mammalian egg and early embryo, contributing to many different aspects of early development. While the contribution of mitochondria to energy production is fundamental, other roles for mitochondria are starting to emerge. Mitochondria are central to intracellular redox metabolism as they produce reactive oxygen species (ROS, the mediators of oxidative stress) and they can generate TCA cycle intermediates and reducing equivalents that are used in antioxidant defence. A high cytosolic lactate dehydrogenase activity coupled with dynamic levels of cytosolic pyruvate is responsible for a very dynamic intracellular redox state in the oocyte and embryo. Mammalian embryos have a low glucose metabolism during the earliest stages of development, as both glycolysis and the pentose phosphate pathway are suppressed. The mitochondrial TCA cycle is therefore the major source of reducing equivalents in the cytosol so that any change in mitochondrial function in the embryo will be reflected in changes in the intracellular redox state. In the mouse, the metabolic substrates used by the oocyte and early embryo each have a different impact on the intracellular redox state. Pyruvate which oxidises the cytosolic redox state, acts as an energetic and redox substrate whereas lactate, which reduces the cytosolic redox state, acts only as a redox substrate. Mammalian early embryos are very sensitive to oxidative stress which can cause permanent developmental arrest before zygotic genome activation and apoptosis in the blastocyst. The oocyte stockpiles antioxidant defence for the early embryo to cope with exogenous and endogenous oxidant insults arising during early development. Mitochondria provide ATP for glutathione (GSH) production during oocyte maturation and also participate in the regeneration of NADPH and GSH during early development. Finally, a number of pathological conditions or environmental insults impair early development by altering mitochondrial function, illustrating the centrality of mitochondrial function in embryo development.

Hydrochlorothiazide and atenolol combination antihypertensive therapy: effects of drug initiation order

For combination antihypertensive therapy with thiazide diuretics and beta-blockers, the effect of the order of initiation of the drugs on the outcome has not been tested. Patients with uncomplicated hypertension were randomized to receive either hydrochlorothiazide (HCTZ) or atenolol monotherapy, followed by addition of the alternative drug. Blood pressure (BP) responses were evaluated by race and order of drug initiation. A total of 368 participants received combination therapy. Among the participants, blacks showed a greater BP-lowering effect than whites did with HCTZ monotherapy (-13.0/-7.4 mm Hg vs. -8.0/-4.2 mm Hg, P < 0.001) but a smaller BP-lowering effect than did whites with atenolol monotherapy (-1.1/-2.9 mm Hg vs. -9.9/-9.2 mm Hg, P < 0.0001). These differences were not evident during combination therapy. However, both groups showed greater response to HCTZ + atenolol than to atenolol + HCTZ (-19.1/-14.2 mm Hg vs. -15.6/-11.3 mm Hg, P < 0.0001). Despite optimal dosing of HCTZ + atenolol, only two-thirds of the participants achieved BP control. In HCTZ/atenolol combination antihypertensive therapy, the order in which the drugs are initiated affects total BP lowering during the first 4-6 months of therapy.

240 EFFECTS OF TIMING AND DIPLOIDIZATION ON ACTIVATION AND DEVELOPMENT OF RAT OOCYTES

The objectives of these studies were (1) to compare the effects of Cytochalasin B (CB) or 6-dimethyl amino purine (DMAP) in combination with SrCl2 on activation and development of rat oocytes and (2) to determine the optimal timing for collection and activation of rat oocytes following superovulation. In Experiment 1, rat oocytes collected at 16–18 h after hCG injection were immediately cultured in 10 mm SrCl2 alone, 10 mm SrCl2 + 2 mm DMAP for 4 h and 10 mm SrCl2 + 5 μg mL–1 CB for 5–6 h, respectively, they were then cultured in KSOM for 20 h and finally cultured in R1ECM for an additional 4 days, all at 37°C, 5% CO2 in air. There were no significant differences in pronuclear formation (SrCl2 alone: 51/53; DMAP: 139/140; CB: 139/140) and cleavage rate (SrCl2 alone: 52/53; DMAP: 129/140; CB: 130/140) observed among three groups (χ2-test, P > 0.05). On Day 5 the frequency of development to blastocyst was not statistically different (P > 0.05) between DMAP (55.71%, 78/140) and CB (54.23%, 76/140) treated groups; however, no blastocysts were produced in 10 mm SrCl2 alone. In Experiment 2, oocytes were collected at 14, 16, 18, 20 and 22 hours after hCG injections, respectively, and they were immediately cultured in 10 mm SrCl2 + 2 mm DMAP for 4 h and then cultured in the same conditions described for Experiment 1. Although development to blastocyst was slightly lower in the 14-h group (43.50%, 47/108), no significant differences in the frequencies of pronuclear formation, cleavage on Day 1 or development to blastocyst on Day 5 were observed between groups (χ2-test, P > 0.05) (Table 1). All experiments were repeated at least three times. In conclusion, our results showed that SrCl2 combined with either CB or DMAP could equally, effectively activate rat oocytes. In contrast rat haploid oocytes activated in the absence of CB or DMAP were not able to develop to the blastocyst stage. Furthermore, rat oocytes collected between 14 and 22 h after hCG injection had an equal potential to develop to the blastocyst stage after activation by 10 mm SrCl2 + 2 mm DMAP. Table 1.Development of rat oocytes activated at different time points following