Effect of supplement crude protein concentration on milk production over the main grazing season and on nitrogen excretion in late-lactation grazing dairy cows.

The objectives of this study are to evaluate the effects of (1) a potential interaction between supplement crude protein (CP) concentration and differing cow genotypes on milk production, (2) differing cow genotypes on milk production, and (3) decreasing the supplement CP concentration on milk production and N excretion during the main grazing season within a spring-calving herd. A 2 × 2 factorial arrangement experiment, with 2 feeding strategies [14%; n = 30 (lower CP; LCP) and 18%; n = 28 (higher CP; HCP) CP concentrate supplements] offered at varying levels according to pasture availability and days in milk (DIM) was conducted over the main grazing season from April 3 to September 3, 2019, at University College Dublin Lyons Farm. Cows were also grouped into 2 genotype groups: lower milk genotype; n = 30 [LM; milk kg predicted transmitting ability (PTA): 45 ± 68.6 (mean ± SD); fat kg PTA: 10 ± 4.9; and protein kg PTA: 7 ± 2.3] and higher milk genotype; n = 28 [HM; milk kg PTA: 203 ± 55.0; fat kg PTA: 13 ± 3.8; and protein kg PTA: 10 ± 2.4]. A total of 46 multiparous and 12 primiparous (total; 58) Holstein Friesian dairy cows were blocked on parity and balanced on DIM, body condition score, and Economic Breeding Index. Cows were offered a basal diet of grazed perennial ryegrass pasture. The N partitioning study took place from August 25 to 30, 2019 (187 ± 15.2 DIM). No interactions were observed for any milk production or milk composition parameter. No effect of supplement CP concentration was observed for any total accumulated milk production, daily milk production, or milk composition parameter measured. The HM cows had increased daily milk yield (+1.9 kg), fat and protein (+0.15 kg), and energy-corrected milk (+1.7 kg), compared with the LM cows. Furthermore, HM cows had decreased milk protein concentration (-0.1%) compared with LM cows. For the N partitioning study, cows offered LCP had increased pasture dry matter intake (PDMI; +0.9 kg/d), dietary N intake (+0.022 kg/d), feces N excretion (+0.016 kg/d), and decreased N partitioning to milk (-2%), and N utilization efficiency (-2.3%). In conclusion, offering cows LCP had no negative influence on milk production or milk composition over the main grazing season where high pasture quality was maintained. However, any potential negative effects of offering LCP on milk production may have been offset by the increased PDMI. Furthermore, offering cows LCP decreased N utilization efficiency due to the higher PDMI and feed N intake associated with cows on this treatment in our study.

Impact of the take ACTION Train-the-Trainer model of opioid overdose education with naloxone distribution- who benefits?

BACKGROUND: Overdose education with naloxone distribution (OEND) is a key national strategy to reduce morbidity and mortality related to opioid overdoses. Train-the-trainer model has been one method to increase the pool of trainers to facilitate greater dissemination of OEND. This exploratory study seeks to (1) evaluate participant's change in knowledge and confidence, (2) examine if pre- and post-training test outcomes differed by occupation and level of experience, and (3) determine if train-the-trainer participants trained others 6 months later. Methods: Fifteen train-the-trainer sessions were delivered to staff from community organizations who served high-risk clients in four counties whose overdose death rates ranged from 11.2 to 32.8 per 100,000. Participants were administered pre- and post-training tests from September 2017 to December 2018. A follow-up survey was conducted 6 months post-training to evaluate outcomes. Final paired pre-and post-training surveys of 109 participants were used for analysis. Paired sample t-tests were used to evaluate changes in the knowledge and confidence in teaching others. One-way ANOVA compared the change scores across groups with different demographic or experiential characteristics. Kruskal-Wallis Test was used for Likert scales. Results: The one and one-half hour train-the-trainer curriculum increased participants' knowledge and confidence to teach others (p < .001). This was particularly true for participants who had no prior experience compared to those who had some experience with naloxone (p = .0003). Changes in confidence to teach others significantly improved among demographic subgroups of participants. At 6 months after completing the train-the-trainer curriculum, 14 participants had trained 243 new trainees. Conclusions: Implementing a train-the-trainer model for OEND increases knowledge and participants' confidence to teach others. This demonstrates the important potential of the train-the-trainer model to respond to the growing opioid overdose epidemic.

TACI is a TRAF-interacting receptor for TALL-1, a tumor necrosis factor family member involved in B cell regulation.

We and others recently reported tumor necrosis factor (TNF) and apoptosis ligand-related leukocyte-expressed ligand 1 (TALL-1) as a novel member of the TNF ligand family that is functionally involved in B cell proliferation. Transgenic mice overexpressing TALL-1 have severe B cell hyperplasia and lupus-like autoimmune disease. Here, we describe expression cloning of a cell surface receptor for TALL-1 from a human Burkitt's lymphoma RAJI cell library. The cloned receptor is identical to the previously reported TNF receptor (TNFR) homologue transmembrane activator and calcium modulator and cyclophilin ligand (CAML) interactor (TACI). Murine TACI was subsequently isolated from the mouse B lymphoma A20 cells. Human and murine TACI share 54% identity overall. Human TACI exhibits high binding affinities to both human and murine TALL-1. Soluble TACI extracellular domain protein specifically blocks TALL-1-mediated B cell proliferation without affecting CD40- or lipopolysaccharide-mediated B cell proliferation in vitro. In addition, when injected into mice, soluble TACI inhibits antibody production to both T cell-dependent and -independent antigens. By yeast two-hybrid screening of a B cell library with TACI intracellular domain, we identified that, like many other TNFR family members, TACI intracellular domain interacts with TNFR-associated factor (TRAF)2, 5, and 6. Correspondingly, TACI activation in a B cell line results in nuclear factor kappaB and c-Jun NH(2)-terminal kinase activation. The identification and characterization of the receptor for TALL-1 provides useful information for the development of a treatment for B cell-mediated autoimmune diseases such as systemic lupus erythematosus.

Evaluation of production efficiencies at pasture of lactating suckler cows of diverse genetic merit and replacement strategy.

Feed costs account for the largest proportion of direct cost within suckler beef production systems. By identifying the cow type with enhanced capability of converting grazed herbage to beef output across lactations, suckler cow systems would become more efficient and sustainable. The objective of this study was to estimate grass DM intake (GDMI) and production efficiency among lactating suckler cows of diverse genetic merit for the national Irish maternal index (Replacement Index) which includes cow efficiency components such as milk yield and feed intake. Data from 131 cows of diverse genetic merit within the Replacement Index, across two different replacement strategies (suckler or dairy sourced), were available over two grazing seasons. Milk yield, GDMI, cow live weight (BW) and body condition score (BCS) were recorded during early, mid and late-lactation, with subsequent measures of production efficiency extrapolated. Genetic merit had no significant effect on any variables investigated, with the exception of low genetic merit (LOW) cows being 22 kg heavier in BW than high genetic merit (HIGH) cows (P < 0.05). Beef cows were 55 kg heavier in BW (P < 0.001), had a 0.31 greater BCS (P < 0.05) and 0.30 Unité Fourragère Lait (UFL) greater energy requirement for maintenance compared to dairy sourced beef × dairy crossbred (BDX) cows (P < 0.001). The BDX had 0.8 kg greater GDMI, produced 1.8 kg more milk (P < 0.001), had a 0.8 UFL greater energy requirement for lactation and produced weanlings that were 17 kg heavier in BW than beef cows (P < 0.05). Subsequent efficiency variables of milk per 100 kg BW (P < 0.001), milk per kg GDMI (P < 0.001) and GDMI per 100 kg BW (P < 0.001) were more favourable for BDX. The correlations examined showed GDMI had moderate positive correlations (P < 0.001) with intake per 100 kg BW, net energy intake per kg milk yield, RFI and intake per 100 kg calf weaning weight but was weakly negatively correlated to milk yield per kg GDMI (P < 0.001). No difference was observed across genetic merit for beef cows for any of the traits investigated. Results from the current study showed that, while contrasting replacement strategies had an effect on GDMI and production efficiency, no main effect was observed on cows diverse in genetic merit for Replacement Index. Nonetheless, utilising genetic indexes in the suckler herd is an important resource for selecting breeding females for the national herd and phenotypic performance generated from this study can be included in future genetic evaluations to improve reliability of genetic values.

Prescription opioid misuse motive latent classes: outcomes from a nationally representative US sample.

AIMS: Prescription opioid misuse (POM) contributes to a larger opioid crisis in the US and Canada, with over 17 000 US POM-related overdose deaths in 2017. Our aims were to (1) identify specific profiles of respondents based on POM motives using the US National Survey on Drug Use and Health (NSDUH) and (2) compare profile respondents on sociodemographics, substance use and mental and physical health outcomes. METHODS: Analyses included 2017-18 NSDUH respondents with data on POM motives (n = 4810). POM was defined as prescription opioid use in a way not intended by the prescriber, including use without a prescription, in larger amounts or more frequently. Nine POM motives for the most recent episode were assessed, including 'to relieve physical pain' and 'to get high'. Latent classes, based on POM motives, were estimated. Classes were compared on sociodemographics, substance use and physical and mental health outcomes. RESULTS: Eight latent classes were identified (in order of prevalence): pain relief only, relax-pain relief, sleep-pain relief, multi-motive, high, experimenter, emotional coping and dependent/hooked. Compared to the pain relief only group, the high and multi-motive classes had higher odds of all substance use outcomes, with the dependent/hooked class having higher odds on all but one outcome. Six of the eight classes had higher odds of past-year mental health treatment and suicidal ideation than the pain relief only class. CONCLUSIONS: Screening for pain, pain conditions, problematic substance use and psychopathology are recommended in those with any POM. While those in the dependent/hooked, multi-motive and emotional coping classes are most likely to have prescription opioid use disorder (OUD), screening for OUD symptoms in all individuals with POM is also warranted.

Effect of cow replacement strategy on cow and calf performance in the beef herd.

Two contrasting replacement strategies are used by Irish beef farmers to select replacement females - animals sourced from within the suckler beef herd and sourced from the dairy herd. The objective of this study was to investigate the effect of replacement strategy (i.e. beef v. beef×dairy (BDX)) on cow and calf performance using data from the national beef database across a range of beef and dairy breeds. The association between replacement strategy and calving difficulty score, calving interval, weaning weight, weaning price and all carcass traits was investigated using a mixed model. The effect of replacement strategy on cow survival, calving dystocia and calf perinatal mortality was quantified using logistic regression. Beef cows were older (10.92 days; P<0.001) at their first calving, but were 1.15 times (P<0.01) more likely to survive to a subsequent lactation compared with BDX cows. Calving interval was 1.53 days shorter (P<0.001) for BDX compared with beef cows. Greater calving difficulty and calving dystocia was associated with beef cows (P<0.001) relative to BDX. However, BDX were 1.36 times (P<0.001) more likely to have a dead calf at birth relative to beef cows. Calves weaned from BDX were heavier (18.49 kg; P<0.001) at weaning, reached slaughter 12.8 days earlier (P<0.001), had 7.99 kg heavier carcass (P<0.001) and a greater fat score (P<0.001) compared with the progeny of beef cows. Beef cow progeny had a superior conformation score (0.5; P<0.001) and achieved a greater price per kilogram (P<0.001) compared with progeny from BDX. Beef cull cows had a heavier carcass (5.58 kg), superior carcass conformation, greater carcass price per kilogram and greater overall carcass value (P<0.001) than BDX. Results from this study show that replacement strategy is of fundamental importance depending on the type of system implemented by farmers and consideration must be given to the traits of importance within the context of the individual production system.

Developing and validating a model to predict the dry matter intake of grazing lactating beef cows.

Current techniques for measuring the dry matter intake (DMI) of grazing lactating beef cows are invasive, time consuming and expensive making them impractical for use on commercial farms. This study was undertaken to explore the potential to develop and validate a model to predict DMI of grazing lactating beef cows, which could be applied in a commercial farm setting, using non-invasive animal measurements. The calibration dataset used to develop the model was comprised of 94 measurements recorded on 106 beef or beef-dairy crossbred cows (maternal origin). The potential of body measurements, linear type scoring, grazing behaviour and thermal imaging to predict DMI in combination with known biologically plausible adjustment variables and energy sinks was investigated. Multivariable regression models were constructed for each independent variable using SAS PROC REG and contained milk yield, BW, parity, calving day and maternal origin (dairy or beef). Of the 94 variables tested, 32 showed an association with DMI (P < 0.25) upon multivariable analysis. These variables were incorporated into a backwards linear regression model using SAS PROC REG. Variables were retained in this model if P < 0.05. Five variables; width at pins, full body depth, ruminating mastications, central ligament and rump width score, were retained in the model in addition to milk yield, BW, parity, calving day and maternal origin. The inclusion of these variables in the model increased the predictability of DMI by 0.23 (R2 = 0.68) when compared to a model containing milk yield, BW, parity, calving day and maternal origin only. This model was applied to data recorded on an independent dataset; a herd of 60 lactating beef cows two years after the calibration study. The R2 for the validation was 0.59. Estimates of DMI are required for measuring feed efficiency. While acknowledging challenges in applicability, the findings suggest a model such as that developed in this study may be used as a tool to more easily and less invasively estimate DMI on large populations of commercial beef cows, and therefore measure feed efficiency.

Does misuse lead to a disorder? The misuse of prescription tranquilizer and sedative medications and subsequent substance use disorders in a U.S. longitudinal sample.

OBJECTIVES: We used two waves of National Epidemiologic Survey on Alcohol and Related Conditions (NESARC) data and examined whether the misuse of prescription tranquilizers or sedatives at Wave 1 was associated with either continued misuse, tranquilizer/sedative use disorder, or other substance use disorder (SUD) at Wave 2. METHODS: Prospective data were analyzed from structured diagnostic interviews using the Alcohol Use disorders and Associated Disabilities Interview Schedule: DSM-IV Version (AUDADIS-DSM-IV). A nationally representative sample of 34,653 of U.S. adults, 18years or older at Wave 1 (2001-2002), were re-interviewed at Wave 2 (2004-2005). After applying the survey weights, the sample represented a population that was 52% female, 71% White, 12% Hispanic, 11% African American, 4% Asian and 2% Native American or other. RESULTS: An estimated 79% of adults who engaged in tranquilizer or sedative misuse at Wave 1 had stopped using these drugs at Wave 2. Only a small percentage (4.3%) of misusers at Wave 1 had a tranquilizer or sedative use disorder at Wave 2. However, 45% (45.0%) of misusers at Wave 1 had at least one other SUD at Wave 2. Among those in remission from a sedative or tranquilizer use disorder at Wave 1, 4.8% had a tranquilizer or sedative use disorder while 34.7% had at least one other SUD at Wave 2. CONCLUSIONS: Most adults who engaged in the misuse of prescription tranquilizers or sedatives ceased using within 3years; however, their prior misuse was associated with higher prevalence of having a SUD three years later.

Insulin-like growth factor-1 stimulation of lymphopoiesis.

We show that treatment of adult mice with recombinant human insulin-like growth factor 1 (rhIGF-1) induces striking modifications in lymphocyte number and function. 9-mo-old male mice received rhIGF-1 (4 mg/kg per d) or its excipient by subcutaneous infusion from osmotic minipumps for 7 or 14 d. Mice were weighed daily and bled at sacrifice; the spleen and thymus were harvested and single cell suspensions were made for analysis of cell phenotype and cell number. The responses of splenocytes to mitogens (concanavalin A, lipopolysaccharide, and pokeweed mitogen), alloantigens and dinitrophenyl ovalbumin were measured. After either 7 or 14 d of treatment, rhIGF-1 had an overall whole-body anabolic effect, resulting in increased body and organ weights with prominent increases in the weight of the spleen and thymus. Furthermore, the rhIGF-1 treated mice were normoglycemic but had reduced blood urea nitrogens, again reflecting the anabolic activity of rhIGF-1. The increased spleen and thymus weights were associated with a large increase in the number of lymphocytes in both organs. In addition to an increase in T cells, specifically CD4+ T cells, a dramatic increase in splenic B cells was also observed. This increase was accompanied by an enhanced responsiveness to dinitrophenyl ovalbumin resulting in increased immunoglobulin production. However, despite the increases in cellularity, there was a decrease in the in vitro responses of spleen cells to mitogens after 7 d of rhIGF-1 treatment. In contrast, treatment with rhIGF-1 for 14 d increased both the cell number and mitogenic responses of splenocytes suggesting that some time is required for the cells populating the peripheral organs to gain mitogenic responsiveness. It is clear from these data that rhIGF-1, at doses that have whole-body anabolic activity, can expand cell number in lymphoid tissue in a normal adult mouse. These dual effects of rhIGF-1, of increasing lymphocyte number and activity, indicate that, in a normal adult animal, rhIGF-1 can cause major changes in lymphoid tissues that are of potential benefit to the functioning of the immune system.

Characterization of the in vitro and in vivo species preference of human and murine tumor necrosis factor-alpha.

The species preference of human and murine tumor necrosis factor-alpha (TNF-alpha) was evaluated in human and murine systems for cytotoxic/cytostatic effects and receptor binding in vitro and murine systems for toxicity and antitumor activity in vivo. The in vitro cytotoxic/cytostatic effects of both species TNF-alpha on human and murine cell lines as well as the receptor binding studies using 125I-labeled recombinant human TNF-alpha demonstrated homologous species preferences. Species preference of TNF-alpha was also apparent in toxicity studies with BALB/c nu/nu and CB6F1 mice, and antitumor responses of CB6F1 mice to s.c. Meth A sarcoma implants. Moreover the growth of Meth A sarcoma implanted i.p. was not inhibited by either human or murine TNF-alpha. These results are discussed in view of the potential for underestimation of the biological potency of TNF-alpha from heterologous sources.

Use of digital images to aid in the decision-making for acute upper extremity trauma referral.

UNLABELLED: This study evaluated the use of digital smartphone images in the decision-making for acute upper extremity trauma referrals. Surgeons (n = 15) were presented with ten upper limb trauma scenarios for consideration of immediate transfer. Based on verbal history and with additional images, participants were asked questions regarding diagnosis, injured tissues, recommended management and diagnostic and treatment confidence. Statistical analyses evaluated confidence level changes and relationships between confidence levels and independent variables. Confidence levels for diagnosis and treatment were increased with the provision of smartphone images, and this was statistically significant. The decision to transfer was changed in 22%. The photographs were more useful for amputation versus non-amputation injuries (diagnosis and treatment) and hand versus forearm injuries (diagnosis), and these differences reached statistical significance. Smartphone digital images were shown to be useful for decision-making in acute upper extremity trauma referrals. This improved communication may have implications for health cost savings and patient burden by minimizing unnecessary acute transfers. LEVEL OF EVIDENCE: Diagnostic Level III.

Long-term survival of solid organ allografts by brief anti-lymphocyte function-associated antigen-1 monoclonal antibody monotherapy.

Strategies targeting lymphocyte function-associated antigen-1 (LFA-1, CD11a/CD18) and intercellular adhesion molecule-1 (ICAM-1) have previously been shown to produce long-term survival of solid organ allografts in animals only when both CD11a and ICAM-1 are targeted for a brief (6-7 days) time or when extended (14 weeks) treatment with anti-CD11a monoclonal antibody (mAb) is administered. We show that recipient pretreatment followed by a brief (13 days) treatment course with high-dose anti-CD11a mAb alone produces long-term survival of cardiac allografts in the rigorous, nonprimarily vascularized heart allograft model in mice. This treatment regimen induces specific unresponsiveness in our model. In recipients bearing long-term beating cardiac grafts after treatment with anti-CD11a mAb, there still exists a high frequency of potentially antigen-reactive T cells in isolated peripheral blood lymphocyte fractions. Therefore, clonal deletion does not appear to explain the induction of specific unresponsiveness by treatment with anti-CD11a mAb in this model. These findings support the further investigation of the use of high-dose anti-LFA-1 mAb monotherapy in the pre- and early postoperative period to promote solid organ allograft survival.

Opioid-induced stimulation of fetal respiratory activity by [D-Ala2]deltorphin I.

[D-Ala2]deltorphin I effects on fetal respiratory activity was characterized to determine the role delta-opioid receptors play in modulating fetal respiratory activity. [D-Ala2]deltorphin I, infused at 0.3 or 100 micrograms/h, intracerebroventricularly (i.c.v.), stimulated fetal respiratory activity without changing blood pH, PCO2 or PO2. Stimulation by 0.3 micrograms/h, but not 100 micrograms/h, was blocked by i.c.v. infusion of the delta-opioid receptor antagonist, naltrindole. Stimulation by 100 micrograms/h was blocked by the mu 1-opioid receptor antagonist naloxonazine. These data suggest stimulation of fetal respiratory activity by 0.3 micrograms/h [D-Ala2]deltorphin I are mediated specifically through delta-opioid receptors; while [D-Ala2]deltorphin I at 100 micrograms/h is no longer selective for the delta-opioid receptor, and the stimulation may be mediated through the mu 1-opioid receptor.

Selective attention and clinical depression: performance on a deployment-of-attention task.

Clinically depressed and nondepressed individuals completed a deployment-of-attention task developed by I. H. Gotlib, A. L. McLachlan, and A. N. Katz (1988). Results indicated that the clinically depressed individuals perform the task in an unbiased fashion, attending equally to positive-, negative-, and neutral-content stimuli. In contrast, the nondepressed individuals demonstrated a "protective" bias against the perception of negative stimuli by avoiding such material in favor of positive or neutral stimuli. Overall, the results of this study suggest that clinically depressed individuals do not show an attentional bias toward negative information, but rather, fail to demonstrate the positive or protective bias that is evident in nondepressed individuals.

Kienböck disease and negative ulnar variance.

We compared the degree of ulnar variance, measured on standardized radiographs of the wrist, in forty-four patients who had Kienböck disease with that in ninety-nine control subjects who had been selected from a general clinic population and had radiographs of the wrist. The purpose of our study was to determine if there is a true relationship between negative ulnar variance and the development of Kienböck disease. Gender was not found to influence the degree of ulnar variance, but an association was found between age and negative ulnar variance in both the control subjects and the patients who had Kienböck disease. The findings of the present study confirmed an association between negative ulnar variance and the development of Kienböck disease even after correction for the influence of age on the measurement of ulnar variance.

Male and female C57BL/6 mice respond differently to diazepam challenge in avoidance learning tasks.

Benzodiazepines (BZ) impair learning and memory performance of animals. The goal of this study was to examine sex differences in the effects of diazepam on learning and memory of C57BL/6 mice in avoidance paradigms. Male and female C57BL/6 mice were tested in the one-way active avoidance, step-down passive avoidance, and foot-shock pain threshold tasks, following administration of vehicle or diazepam (1 mg/kg). No substantial sex or drug effects on the threshold of the pain response to shock were found. There were no significant differences in avoidance performance between vehicle-treated male and female mice while 1 mg/kg of diazepam produced opposite effects on performance of males and females in both tasks. Diazepam-treated females learned faster in the active avoidance task and showed stronger retention in the passive avoidance task. In contrast, diazepam impaired learning of males in the active avoidance task and had no effect on their performance in the passive avoidance task. Diazepam-induced impairment in males was not due to higher sensitivity to the sedative effect of diazepam as females were more sedated than males on the first trial of the passive avoidance task. Our data showed that sedative and amnesic effects of BZs are not tightly linked. This study also suggests that cognitive effects of BZs in rodents could be sex dependent and highlight the importance of using both sexes in studies on behavioral effects of psychoactive drugs.

A brief method of assessing adult inpatients' level of need for community support systems.

The study examined the usefulness of the Level of Community Support Systems (LOCSS) scale in rating psychiatric inpatients' need for community supports after discharge. The scale was compared with two other instruments, the Community Placement Questionnaire (CPQ) and the Community Supports and Services Checklist (CSSC) in assessing 105 inpatients. LOCSS scale ratings were related to service utilization indicators, to items on the CPQ measuring community functioning ability, and to the CSSC score. The LOCSS scale correctly classified the level of difficulty of community placement for 69 percent of patients, indicating its usefulness as a screening tool in planning community-based psychosocial rehabilitation services.

Direct in vivo observations of embolic events in the microcirculation distal to a small-vessel anastomosis.

This study was done to determine whether microemboli are produced by an arterial anastomosis. Direct in vivo observations were made in an isolated microcirculatory bed lying directly downstream from a newly made anastomosis. The tissue used was the isolated rat cremaster muscle, a new experimental model. The vessel anastomosed was the external iliac artery. Following anastomosis, microemboli were clearly observed in eight of eight animals during the first 30 minutes after clamp release. Embolic events were sometimes of impressive magnitude and in one case were associated with cessation of blood flow throughout the preparation. No microemboli were observed in eight of eight animals subjected only to dissection of the cremaster, nor were any observed in eight of eight animals in which the isolated cremaster was subjected only to 2 hours of clamp ischemia. These findings may be significant in explaining perturbations to blood flow following free-tissue transfer and instances of partial tissue necrosis following apparently successful arterial repair. These findings also identify an important factor (microemboli) to be considered in research on reperfusion injury.

Recipient vessels in head and neck microsurgery: radiation effect and vessel access.

Historical cohort analysis compared free-flap survival rates in 226 irradiated and 108 nonirradiated head and neck reconstructions. The failure rate for the irradiated flaps (3.5 percent) did not differ significantly from that for the nonirradiated group (2.9 percent). A case-control study of the failed irradiated flaps revealed infection and lag time between radiotherapy and surgery as the only factors significantly associated with free flap failure. Salvage techniques (vein grafting, cephalic transposition, and Corlett looping) for recruiting recipient vessels into radically ablated head and neck beds are reviewed.

Comparison of tidal volumes obtained by one-handed and two-handed ventilation techniques.

OBJECTIVES: To compare tidal volumes delivered by one- vs two-handed compressions of a manual resuscitation bag and assess the effects of subject characteristics on those tidal volumes. DESIGN: Subjects (108 healthcare providers from a 500-bed teaching hospital) were assigned randomly to one of two procedures: one- followed by two-handed compression or two- followed by one-handed compression. A 1-liter resuscitation bag, lung performance analyzer and Wright spirometer were used to measure tidal volume. Data collection occurred in a simulated situation. RESULTS: There was a significant difference in tidal volume delivered by one-handed (mean = 694 mL, SD = 111) vs two-handed compressions (mean = 827 mL, SD = 113). Hand size, grip strength, height and weight were correlated with tidal volumes generated by one-handed and two-handed procedures. No other subject characteristics were correlated with tidal volumes. CONCLUSIONS: Tidal volumes delivered by healthcare providers using one- vs two-handed compressions were found to be significantly different, with those delivered by two hands significantly greater than those delivered by one hand. Strength of hand grip was the best predictor of volume delivered and was more strongly correlated with volumes delivered by one rather than two hands.