Docosahexaenoic acid (DHA) intake estimated from a 7-question survey identifies pregnancies most likely to benefit from high-dose DHA supplementation.

BACKGROUND: Two randomized trials found women with low blood docosahexaenoic acid (DHA; an omega 3 fatty acid) had fewer early preterm births (<34 weeks gestation) if they were assigned to high dose DHA supplementation, however, there is currently no capacity for clinicians who care for pregnancies to obtain a blood assessment of DHA. Determining a way to identify women with low DHA intake whose risk could be lowered by high dose DHA supplementation is desired. OBJECTIVE: To determine if assessing DHA intake can identify pregnancies that benefit from high dose DHA supplementation. STUDY DESIGN: This secondary analysis used birth data from 1310 pregnant women who completed a 7-question food frequency questionnaire (DHA-FFQ) at 16.8 ± 2.5 weeks gestation that is validated to assess DHA status. They were then randomly assigned to a standard (200 mg/day) or high dose (800 or 1000 mg/day) DHA supplement for the remainder of pregnancy. Bayesian logistic regressions were fitted for early preterm birth and preterm birth as a function of DHA intake and assigned DHA dose. RESULTS: Participants who consumed less than 150 mg/day DHA prior to 20 weeks' gestation (n = 810/1310, 58.1%) had a lower Bayesian posterior probability (pp) of early preterm birth if they were assigned to high dose DHA supplementation (1.4% vs 3.9%, pp = 0.99). The effect on preterm birth (<37 weeks) was also significant (11.3% vs 14.8%, pp = 0.97). CONCLUSION: The DHA-FFQ can identify pregnancies that will benefit most from high dose DHA supplementation and reduce the risk of preterm birth. The DHA-FFQ is low burden to providers and patients and could be easily implemented in obstetrical practice.

Early and late preterm birth rates in participants adherent to randomly assigned high dose docosahexaenoic acid (DHA) supplementation in pregnancy.

BACKGROUND: Intention-to-treat analyses do not address adherence. Per protocol analyses treat nonadherence as a protocol deviation and assess if the intervention is effective if followed. OBJECTIVE: To determine the rate of early preterm birth (EPTB, <34 weeks gestation) and preterm birth (PTB, <37 weeks gestation) in participants who adhered to a randomly assigned docosahexaenoic acid (DHA) dose of 1000 mg/day. STUDY DESIGN: Eleven hundred women with a singleton pregnancy were enrolled before 20-weeks' gestation, provided a capsule with 200 mg/day DHA and randomly assigned to two additional capsules containing a placebo or 800 mg of DHA. In the Bayesian Adaptive Design, new randomization schedules were determined at prespecified intervals. In each randomization, the group with the most EPTB was assigned fewer participants than the other group. Adherence was defined a priori as a postpartum red blood cell phospholipid DHA (RBC-PL-DHA) ≥5.5%.and post hoc as ≥8.0% RBC-PL-DHA, the latter after examination of postpartum RBC-PL-DHA. Bayesian mixture models were fitted for gestational age and dichotomized for EPTB and PTB as a function of baseline RBC-PL-DHA and dose-adherence. Bayesian hierarchical models were also fitted for EPTB by dose adherence and quartiles of baseline RBC-PL-DHA. RESULTS: Adherence to the high dose using both RBC-PL-DHA cut points resulted in less EPTB compared to 200 mg [Bayesian posterior probability (pp) = 0.93 and 0.92, respectively]. For participants in the two lowest quartiles of baseline DHA status, adherence to the higher dose resulted in lower EPTB (≥5.5% RBC-PL-DHA, quartiles 1 and 2, pp = 0.95 and 0.96; ≥8% RBC-PL-DHA, quartiles 1 and 2, pp = 0.94 and 0.95). Using the Bayesian model, EPTB was reduced by 65%, from 3.45% to 1.2%, using both cut points. Adherence also reduced PTB before 35, 36 and 37 weeks using both cut points (pp ≥ 0.95). In general, performance of the nonadherent subgroup mirrored that of participants assigned to 200 mg. CONCLUSION: Adherence to high dose DHA reduced EPTB and PTB. The largest effect of adherence on reducing EPTB was observed in women with low baseline DHA levels. CLINICALTRIALS: gov (NCT02626299).

Identifying ecological production functions for use in ecosystem services-based environmental risk assessment of chemicals.

There is increasing research interest in the application of the ecosystem services (ES) concept in the environmental risk assessment of chemicals to support formulating and operationalising regulatory environmental protection goals and making environmental risk assessment more policy- and value-relevant. This requires connecting ecosystem structure and processes to ecosystem function and henceforth to provision of ecosystem goods and services and their economic valuation. Ecological production functions (EPFs) may help to quantify these connections in a transparent manner and to predict ES provision based on function-related descriptors for service providing species, communities, ecosystems or habitats. We review scientific literature for EPFs to evaluate availability across provisioning and regulation and maintenance services (CICES v5.1 classification). We found quantitative production functions for nearly all ES, often complemented with economic valuation of physical or monetary flows. We studied the service providing units in these EPFs to evaluate the potential for extrapolation of toxicity data for test species obtained from standardised testing to ES provision. A broad taxonomic representation of service providers was established, but quantitative models directly linking standard test species to ES provision were extremely scarce. A pragmatic way to deal with this data gap would be the use of proxies for related taxa and stepwise functional extrapolation to ES provision and valuation, which we conclude possible for most ES. We suggest that EPFs may be used in defining specific protection goals (SPGs), and illustrate, using pollination as an example, the availability of information for the ecological entity and attribute dimensions of SPGs. Twenty-five pollination EPFs were compiled from the literature for biological entities ranging from 'colony' to 'habitat', with 75% referring to 'functional group'. With about equal representation of the attributes 'function', 'abundance' and 'diversity', SPGs for pollination therefore would seem best substantiated by EPFs at the level of functional group.

Antigen- and receptor-driven regulatory mechanisms. III. Induction of delayed type hypersensitivity to azobenzenearsonate with anti-cross-reactive idiotypic antibodies.

Delayed-type hypersensitivity (DTH) to p-azobenzenearsonate (ABA) can be induced in A/J mice with intravenous injection of minute amounts of anti-cross-reactive idiotypic (CRI) antibodies, providing that the animals have been pretreated 2 d earlier with low doses of cyclophosphamide (50 mg/kg). However intravenous injection of the F(ab')2 fragments of the anti-CRI antibodies or subcutaneous administration with anti-CRI antibodies induces comparable immunity in both cyclophosphamide-pretreated and normal nontreated animals. Furthermore adoptive transfer experiments indicate that lymph node cells taken from animals sensitized with anti-CRI 4 d earlier can adoptively transfer immunity to naive recipients. Transfer of immunity is mediated by a population of thymus-dependent (T) cells, which express idiotypic structures on their surface. Treatment of effector cells with either anti-theta serum or anti-idiotypic antibodies plus complement completely abrogated their ability to transfer immunity. In addition idiotype-bearing suppressor T cells induced with ABA-coupled spleen cells inhibit the development of ABA-specific DTH induced with anti-CRI antibodies. Genetic analysis revealed that the ability of anti-CRI antibodies to induce ABA-specific DTH was linked to Igh-1 heavy-chain allotype. Anti-idiotypic antibodies to the major CRI associated with anti-ABA antibodies in A/J mice failed to induce significant immunity in BALB/c mice (H-2d, Igh-1a). Nevertheless, they were able to induce significant immunity in C.AL20 mice (H-2d, Igh-1d) which possess a heavy-chain allotype similar to that of A/J mice.

Applying a mechanistic model to predict interacting effects of chemical exposure and food availability on fish populations.

The potential environmental impacts of chemical exposures on wildlife are of growing concern. Freshwater ecosystems are vulnerable to chemical effects and wildlife populations, including fish, can be exposed to concentrations known to cause adverse effects at the individual level. Wild fish populations are also often subjected to numerous other stressors simultaneously which in temperate climates often include sustained periods of food limitation. The potential interactive effects of chemical exposures and food limitation on fish populations are however difficult to establish in the field. Mechanistic modelling approaches can be employed to help predict how the physiological effects of chemicals and food limitation on individuals may translate to population-level effects. Here an energy budget-individual-based model was developed and the control (no chemical) model was validated for the three-spined stickleback. Findings from two endocrine active chemical (EAC) case studies, (ethinyloestradiol and trenbolone) were then used to investigate how effects on individual fecundity translated into predicted population-level effects for environmentally relevant exposures. The cumulative effects of chemical exposure and food limitation were included in these analyses. Results show that effects of each EAC on the population were dependent on energy availability, and effects on population abundance were exacerbated by food limitation. Findings suggest that chemical effects and density dependent food competition interact to determine population responses to chemical exposures. Our study illustrates how mechanistic modelling approaches might usefully be applied to account for specific chemical effects, energy budgets and density-dependent competition, to provide a more integrated evaluation of population outcomes in chemical risk assessments.

Endogenous neurosteroids influence synaptic GABAA receptors during postnatal development.

GABA plays a key role in both embryonic and neonatal brain development. For example, during early neonatal nervous system maturation, synaptic transmission, mediated by GABAA receptors (GABAA Rs), undergoes a temporally specific form of synaptic plasticity to accommodate the changing requirements of maturing neural networks. Specifically, the duration of miniature inhibitory postsynaptic currents (mIPSCs), resulting from vesicular GABA activating synaptic GABAA Rs, is reduced, permitting neurones to appropriately influence the window for postsynaptic excitation. Conventionally, programmed expression changes to the subtype of synaptic GABAA R are primarily implicated in this plasticity. However, it is now evident that, in developing thalamic and cortical principal- and inter-neurones, an endogenous neurosteroid tone (eg, allopregnanolone) enhances synaptic GABAA R function. Furthermore, a cessation of steroidogenesis, as a result of a lack of substrate, or a co-factor, appears to be primarily responsible for early neonatal changes to GABAergic synaptic transmission, followed by further refinement, which results from subsequent alterations of the GABAA R subtype. The timing of this cessation of neurosteroid influence is neurone-specific, occurring by postnatal day (P)10 in the thalamus but approximately 1 week later in the cortex. Neurosteroid levels are not static and change dynamically in a variety of physiological and pathophysiological scenarios. Given that GABA plays an important role in brain development, abnormal perturbations of neonatal GABAA R-active neurosteroids may have not only a considerable immediate, but also a longer-term impact upon neural network activity. Here, we review recent evidence indicating that changes in neurosteroidogenesis substantially influence neonatal GABAergic synaptic transmission. We discuss the physiological relevance of these findings and how the interference of neurosteroid-GABAA R interaction early in life may contribute to psychiatric conditions later in life.

Differential expression of erythroid genes in prion disease.

We previously reported reduced expression of erythroid-associated factor (ERAF) within haematopoietic tissues of rodent scrapie models, suggesting an unrecognized role for the erythroid lineage in prion disease. In the present study, we compared the expression of a panel of erythroid genes within four murine scrapie models and five virus infection models with parallels to prion disease pathogenesis. We report that differential expression of erythroid genes is not limited to ERAF, and is a common feature of murine scrapie, dependent on host expression of cellular prion protein. In contrast, erythroid gene expression was not altered following virus infection. Whilst these results further implicate cells of the erythroid lineage in the peripheral pathogenesis of prion disease, analysis of blood from BSE-infected cattle and scrapie-infected sheep reveals that the extent of differential expression of erythroid genes within peripheral blood is not sufficient to provide a discriminatory diagnostic test.

Immunological functions of splenic B-lymphocytes.

The spleen is a key lymphoid organ for generating B-lymphocyte (B cell)-mediated humoral immunity. This review examines the key features and functions of splenic B cells. Splenic B cell subsets, including virgin, memory, and CD5+ B cells, are characterized by their phenotypic markers and functions. Structural aspects of the spleen, including red pulp, follicles, periarterial lymphoid sheaths (PALS), and germinal centers, are related to the B cells localized in these areas. The migratory behavior of B cells in these splenic compartments is considered in the context of antigen exposure, adhesion molecules, and migratory stimuli. Antigen-specific B cells in the spleen are examined with an emphasis on their in situ characteristics assessed by immunocytochemical methods. This includes the detection of antigen-binding antibody-forming cells (AFC), idiotype-producing AFC, and the application of computer-aided imaging to analyze these cells. Interactions between splenic B cells and other cell types, such as T-lymphocytes (T cells) and antigen-processing/presenting cells like macrophages and dendritic cells, are briefly examined. Cytokines that influence splenic B cells are reviewed. Interactions between B cells and the neuroendocrine system are discussed briefly. The functions of splenic B cells are considered. Antibody production, cytokine synthesis, and potential immunoregulatory activities are considered.

Idiotypic relationships among anti-p-azophenylarsonate antibodies: shared public idiotopes among A-strain minor CRI and BALB/c CRIc.

Four monoclonal antibodies, each previously categorized as a member of the minor cross-reactive idiotypes of the A/J anti-p-azophenylarsonate (Ar) response, have been subjected to a detailed study of their idiotopes. All four were found to share at least one common public idiotope, with other public idiotopes expressed on some and not others of these antibodies. These CRIm were compared with 7 monoclonal anti-Ar derived from BALB/c mice that have been previously found to bear idiotopes of the BALB/c CRIc. Considerable homology of public idiotopes was demonstrated between the 4 A/J CRIm and 5 of the BALB/c CRIc(+) anti-Ar referred to as the 5AF6 family. The implications of these findings with respect to the structural basis and regulation of these idiotypes are discussed.

Two BALB/c anti-arsonate idiotype families: two heavy chain variable regions (Vh) shared with anti-DNP antibodies are used by one family while a Vh similar to anti-GAT antibodies is used by the other.

Amino terminal amino acid sequences were obtained for both the heavy (H) and light (L) chains of seven BALB/c anti-arsonate (Ar) monoclonal antibodies representing the 5AF6 and 3C6 idiotype (id) families described in this strain. 5AF6 family H chains showed strong homology to the germ-line gene sequence for the A strain 36-60 family. However, four to five identical H chain sequence differences for two of these antibodies (5AF6 and 95B5), as well as two previously reported related sequences (92D5, 94B10), suggested they were encoded by a different Vh. The 36-60 family Vh genes have been shown to be identical to the Vh gene of the anti-DNP binding myeloma M460 [Dzierzak et al., J. Immun. 136, 1864-1870 (1986)]. H chains amino acid sequences derived from an id-460+ anti-DNP hybridoma and a germ-line gene differing from the 30-60-like Vh sequence [Dzierzak et al., J. Immun. 136, 1864-1870 (1986)] were found to be virtually identical to the 95B5 and 5AF6 Vh sequences. This suggests that the same two related H chains making up two subsets of the 5AF6 anti-Ar id family are also both used in two subsets of the id-460 anti-DNP response. 5AF6 family L chains were highly homologous to the other Vk2 L chains of the 36-60 family. 3C6 family H chains can be placed in the Vh l group, are unrelated to the described anti-Ar H chain families, and have been placed in a new anti-Ar Vh family, Ars-E. The 3C6 H is similar, however, to a Vh used by a BALB/c anti-GAT idiotype family of antibodies. 3C6 L chains were of the murine kappa chain group, Vk8 and most resembled an L chain from an A strain monoclonal anti-Ar having no defined idiotype.

Pharmacokinetics and pharmacodynamics of a new cardiotonic vasodilator agent, 349U85, in normal subjects.

OBJECTIVE: To assess the pharmacodynamics and pharmacokinetics of single oral doses of a new vasodilator-cardiotonic agent, 349U85 hydrochloride [6-piperidino-2(1H)-quinolinone hydrochloride], in healthy male subjects. METHODS: This randomized, parallel, double-blind, placebo-controlled, dose escalation trial was conducted at a university-based clinical research center among 27 healthy male subjects. Data measurements used in the study included cardiac index, supine and standing blood pressure, 24-hour ambulatory electrocardiography, and 12-lead electrocardiography. RESULTS: Doses from 2 mg to 250 mg were well tolerated. Cardiac index, supine heart rate, and orthostatic hypotension, indicators of inotropic, chronotropic, and vasodilator effects, respectively, correlated to plasma concentrations of 349U85 and of its metabolite, 661U88. Results suggest that 349U85 may be more responsible for inotropic effects, whereas 661U88 may be more responsible for vasodilatory and chronotropic effects. These results are consistent with the preclinical pharmacologic profile for these two compounds. Headache, orthostatic dizziness, and hypotension tended to occur more frequently at higher doses and were temporally related to drug administration. Pharmacokinetic analyses indicate nonlinearity of 349U85 and 661U88, suggestive of saturation of metabolism and large interindividual variability in maximum plasma drug concentration and area under the plasma concentration-time curve. The source of the variability is not known. The time to maximum distribution was approximately 0.7 hours for both 349U85 and 661U88; the terminal elimination half-life was 1 hour for 349U85 and 3 hours for 661U88. Holter monitoring revealed asymptomatic increases in ventricular and supraventricular ectopic activity in some volunteers; ectopy appeared to be related to the dose of 349U85 and generally occurred at higher doses.

Complete nucleotide sequence of an EcoRI-1.35-kb repeated element of mouse: homology with the cellular flanking region between two intracisternal A-particle genes.

The complete DNA sequence (1369 bp) of an EcoRI-1.35-kb repeated element (ER-1) of the mouse BamHI family has been determined. Analysis of this sequence revealed that a portion of the 3' end (positions 1277-1369) of ER-1 was found to share 91% homology with the flanking cellular sequence between two adjacent intracisternal A-particle (IAP) genes, IAP-19A and IAP-19B.

Combined immunocytochemical staining and image analysis for the study of lymphocyte specificity and function in situ.

Immunocytochemical staining methods were combined with computer-aided image analysis to quantitate relative intracytoplasmic and cell membrane products within single lymphoid cells. Lymphoid cells fixed to microscope slides were immunocytochemically stained and the densities of immunocytochemical stains for individual lymphoid cells were determined on video-camera-captured microscopic images to quantitate synthesized and fully assembled antibody molecules detected by an anti-idiotypic antibody. Similarly, expression of a lymphoid cell membrane molecule, Ly-1, was comparatively quantitated in individual lymphoid cells. Densitometric analysis of tissue sections was utilized to measure tissue areas and quantitate cell nuclei in tissues. Two-color immunocytochemical staining and sequential image analyzer-determined locations of individual cells in tissues allowed unambiguous identification of doubly stained cells in their native tissue environment. This analysis was applied to the in situ identification of antibody forming cells producing the CRIc idiotype of the BALB/c anti-arsonate response and a determination of the mu chain usage by those individual cells. Applications of combined immunocytochemistry and computerized image analysis to studies of in vivo immunologic functions are discussed.

Detection of antibody, idiotype, and anti-idiotype forming cells by in situ immunocytochemical staining.

Methods are described for the immunocytochemical staining of cryostat sections of lymphoid tissue with enzyme conjugates of antigen, idiotype (Id) and anti-idiotype. Results established this as a useful approach, for simultaneously detecting Id and anti-Id antibody forming cells (AFC) in situ. As a model, the 5AF6 Id family associated with the BALB/c mouse antibody response against the p-azophenyl-arsonate (Ar) epitope was examined by two-color immunocytochemical staining, allowing the simultaneous detection of both Id+ and Id- anti-Ar AFC. Spleens from mice secondarily immunized with Ar antigen but not normal mice contained anti-Id AFC stained with the 5AF6 Id but not with another immunoglobulin of the same isotype. A sequential staining method was developed which allowed the detection of both Id and anti-Id AFC in the same tissue, thus providing a means of examining Id and anti-Id antibody networks in intact lymphoid tissues.

Chamber for testing metered-dose propellant-driven aerosols of immunologically relevant proteins.

A small aerosol chamber was developed for testing and delivery of aerosols of immunologically important proteins to the respiratory tracts of rodents. The chamber was designed to accommodate the small aerosol volumes produced by metered-dose propellant-driven aerosol canisters. Metered bursts of protein aerosols released into the chamber could be sampled for their particle sizes or used to expose the noses of up to six mice to the aerosols. The chamber consisted of a polyethylene tank with two removable plexiglass end plates. One end plate accommodated the propellant-driven, metered-dose, aerosol vial. The other end of the tank was fitted with a plate accepting aerosol sampling devices or a plate containing mouse restrainers. Uniform concentrations of aerosolized proteins were obtained at different positions in the chamber when sampled for particles of respirable size. Respirable-sized protein particles produced by propellant-driven aerosols ranged from 5 to 50% of total aerosolized protein. Propellant-driven aerosols of proteins released in the chamber produced aerosol particles equivalent to 15-26 micrograms of total protein exposure to the respiratory tract of each mouse. The chamber permitted aerosol releases without risk of operator exposure. This aerosol chamber will permit the testing of protein aerosols for their immunologic consequences to the respiratory tract. Potential proteins for testing in this device include immunizing vaccine antigens, immunomodulating cytokine proteins, and passive antibody aerosol therapies against respiratory infections.

A comparison of prophylactic antibiotic regimens against airborne orthopaedic wound contamination.

Deep infection remains a major complication of joint replacement surgery despite advances in theatre design, surgical technique and antibiotic prophylaxis. Major randomized controlled trials to determine the most effective antibiotic prophylaxis are difficult to construct and interpret. In a conventional theatre, most orthopaedic intra-operative wound contamination arrives by the airborne route. This paper describes a unique method used to compare antibiotics against airborne bacteria. Seven antibiotics were incorporated into blood agar at concentrations equivalent to serum levels. Plates were then exposed to airborne theatre bacteria using a multiple synchronous collection technique. After incubation, the percentage kill was calculated for each antibiotic. At concentrations equivalent to serum level 1h post i.v. dose, all the antibiotics proved highly effective, with kill rates > 95%. Imipenem and co-amoxiclav significantly outperformed the other antibiotics with kill rates of 99.6% and 99.4%, respectively. At trough levels, the antibiotics achieved kill rates from 61% to 97.6%. Future randomized controlled trials comparing large numbers of antibiotics in the setting of an already low infection rate are inappropriate. This technique for comparing antibiotic prophylaxis in quick, inexpensive and repeatable. The superiority of imipenem is not unexpected, but of more interest is the effectiveness of co-amoxiclav over the presently favoured cefuroxime.

Epidemiology and control of vancomycin-resistant enterococci (VRE) in a renal unit.

This study reports an outbreak of infection and colonization caused by vancomycin-resistant enterococci (VRE) in the renal service of a large teaching hospital. The polymerase chain reaction and pulsed-field gel electrophoresis were used to study the epidemiology of 26/34 strains of vancomycin-resistant Enterococcus faecalis and Enterococcus faecium from the outbreak in comparison with five strains from other hospitals in Edinburgh and the Borders, and three from other wards in the Royal Infirmary. The study revealed a heterogeneous population of vancomycin-resistant E. faecalis. Over 60% of E. faecium isolates had matching pulsed-field gel electrophoresis patterns and all of these were of VanA phenotype. These results suggest that clonal spread of VanA phenotype E. faecium within and possibly between hospitals is the major vancomycin-resistant enterococcal problem in Edinburgh. Screening of patients and isolation of colonized and infected patients appear to have been successful in controlling the spread of VRE.

Newborn screening for cystic fibrosis using an enzyme linked immunoabsorbent assay (ELISA) technique.

Neonatal screening for cystic fibrosis (CF) has been conducted using conventional radioimmunoassay. An alternative immunoassay approach has been developed and applied to screening 35,550 newborns. Seventeen confirmed CF infants were detected by both assays. This monoclonal antibody-based enzyme immunoassay using microtitre plate ELISA technology has proved effective in case finding and offers a number of advantages. A reduced labour component, ease of handling, use of nonradioactive reagents, long reagent shelf-life, greater specificity and a reduction in potential sample handling and transposition errors combine to make this technology appropriate for a large volume neonatal screening laboratory.

Interscalene block with a nerve stimulator: a deltoid motor response is a satisfactory endpoint for successful block.

BACKGROUND AND OBJECTIVES: The interscalene brachial plexus block (ISB) is an effective and well-established anesthetic technique for shoulder surgery. Using nerve stimulation as an aid in block placement, a motor response (twitch) in the biceps or a more distal upper limb muscle has been recommended to indicate accurate needle placement. Our clinical experience, as well as anatomic reasoning, suggests that a deltoid twitch may be just as effective as one in the biceps for predicting successful block. This prospective clinical study was undertaken to compare a deltoid with a biceps twitch with respect to onset and success of motor block. METHODS: A total of 160 patients scheduled for shoulder surgery were studied prospectively. Interscalene blocks were performed using neurostimulation according to our standard technique. Twitches of the deltoid or biceps or both, whichever appeared first, were accepted and used as the endpoint for needle placement and injection of local anesthetic. Motor block success, i.e., patient inability to lift the arm against gravity, and minutes to motor block onset were recorded. RESULTS: There was 1 failed motor block in the deltoid group and none in the other groups (not a statistically significant difference). When the same local anesthetic was used, there were no statistically significant differences in onset times between the biceps, deltoid, or biceps/deltoid groups. CONCLUSIONS: A deltoid twitch is as effective as a biceps twitch in determining accurate needle placement for ISB and in predicting successful motor block. Acceptance of a deltoid twitch during ISB eliminates the need for further probing and may translate into better patient acceptance and in a smaller risk of needle-induced nerve damage.