Barriers to the Initiation of Telecommunicator-CPR during 9-1-1 Out-of-Hospital Cardiac Arrest Calls: A Qualitative Study

INTRODUCTION

Fewer than 10% of individuals who suffer out-of-hospital cardiac arrest (OHCA) survive with good neurologic function. Bystander CPR more than doubles the chance of survival, and telecommunicator-CPR (T-CPR) during a 9-1-1 call substantially improves the frequency of bystander CPR.

OBJECTIVE

We examined the barriers to initiation of T-CPR.

METHODS

We analyzed the 9-1-1 call audio from 65 EMS-treated OHCAs from a single US 9-1-1 dispatch center. We initially conducted a thematic analysis aimed at identifying barriers to the initiation of T-CPR. We then conducted a conversation analysis that examined the interactions between telecommunicators and bystanders during the recognition phase (i.e., consciousness and normal breathing).

RESULTS

We identified six process themes related to barriers, including incomplete or delayed recognition assessment, delayed repositioning, communication gaps, caller emotional distress, nonessential questions and assessments, and caller refusal, hesitation, or inability to act. We identified three suboptimal outcomes related to arrest recognition and delivery of chest compressions, which are missed OHCA identification, delayed OHCA identification and treatment, and compression instructions not provided following OHCA identification. A primary theme observed during missed OHCA calls was incomplete or delayed recognition assessment and included failure to recognize descriptors indicative of agonal breathing (e.g., "snoring", "slow") or to confirm that breathing was effective in an unconscious victim.

CONCLUSIONS

We observed that modifiable barriers identified during 9-1-1 calls where OHCA was missed, or treatment was delayed, were often related to incomplete or delayed recognition assessment. Repositioning delays were a common barrier to the initiation of chest compressions.

Novel Negative Pressure Procedural Tent Reduces Aerosolized Particles in a Simulated Prehospital Setting

BACKGROUND/OBJECTIVE

The coronavirus disease 2019 (COVID-19) pandemic has challenged the ability of Emergency Medical Services (EMS) providers to maintain personal safety during the treatment and transport of patients potentially infected. Increased rates of COVID-19 infection in EMS providers after patient care exposure, and notably after performing aerosol-generating procedures (AGPs), have been reported. With an already strained workforce seeing rising call volumes and increased risk for AGP-requiring patient presentations, development of novel devices for the protection of EMS providers is of great importance.Based on the concept of a negative pressure room, the AerosolVE BioDome is designed to encapsulate the patient and contain aerosolized infectious particles produced during AGPs, making the cabin of an EMS vehicle safer for providers. The objective of this study was to determine the efficacy and safety of the tent in mitigating simulated infectious particle spread in varied EMS transport platforms during AGP utilization.

METHODS

Fifteen healthy volunteers were enrolled and distributed amongst three EMS vehicles: a ground ambulance, an aeromedical-configured helicopter, and an aeromedical-configured jet. Sodium chloride particles were used to simulate infectious particles and particle counts were obtained in numerous locations close to the tent and around the patient compartment. Counts near the tent were compared to ambient air with and without use of AGPs (non-rebreather mask, continuous positive airway pressure [CPAP] mask, and high-flow nasal cannula [HFNC]).

RESULTS

For all transport platforms, with the tent fan off, the particle generator alone, and with all AGPs produced particle counts inside the tent significantly higher than ambient particle counts (P <.0001). With the tent fan powered on, particle counts near the tent, where EMS providers are expected to be located, showed no significant elevation compared to baseline ambient particle counts during the use of the particle generator alone or with use of any of the AGPs across all transport platforms.

CONCLUSION

Development of devices to improve safety for EMS providers to allow for use of all available therapies to treat patients while reducing risk of communicable respiratory disease transmission is of paramount importance. The AerosolVE BioDome demonstrated efficacy in creating a negative pressure environment and workspace around the patient and provided significant filtration of simulated respiratory droplets, thus making the confined space of transport vehicles potentially safer for EMS personnel.

Assessment of Telecommunicator Cardiopulmonary Resuscitation Performance During Out-of-Hospital Cardiac Arrest Using a Standardized Tool for Audio Review

OBJECTIVE

Telecommunicator cardiopulmonary resuscitation (T-CPR) is a critical component of optimized out-of-hospital cardiac arrest (OHCA) care. We assessed a pilot tool to capture American Heart Association (AHA) T-CPR measures and T-CPR coaching by telecommunicators using audio review.

METHODS

Using a pilot tool, we conducted a retrospective review of 911 call audio from 65 emergency medical services-treated out-of-hospital cardiac arrest (OHCA) patients. Data collection included events (e.g., OHCA recognition), time intervals, and coaching quality measures. We calculated summary statistics for all performance and quality measures.

RESULTS

Among 65 cases, the patients' mean age was 64.7 years (SD: 14.6) and 17 (26.2%) were women. Telecommunicator recognition occurred in 72% of cases (47/65). Among 18 non-recognized cases, reviewers determined 12 (66%) were not recognizable based on characteristics of the call. Median time-to-recognition was 76 seconds (n=40; IQR:39-138), while median time-to-first-instructed-compression was 198 seconds (n=26; IQR:149-233). In 36 cases where coaching was needed, coaching on compression-depth occurred in 27 (75%); -rate in 28 (78%); and chest recoil in 10 (28%) instances. In 30 cases where repositioning was needed, instruction to position the patient's body flat occurred in 18 (60%) instances, on-back in 22 (73%) instances, and on-ground in 22 (73%) instances.

CONCLUSIONS

Successful collection of data to calculate AHA T-CPR measures using a pilot tool for audio review revealed performance near AHA benchmarks, although coaching instructions did not occur in many instances. Application of this standardized tool may aid in T-CPR quality review.

Safety, Efficacy, and Cost of 0.4-mg Versus 2-mg Intranasal Naloxone for Treatment of Prehospital Opioid Overdose

BACKGROUND

Intranasal naloxone is commonly used to treat prehospital opioid overdose. However, the optimal dose is unclear, and currently, no study exists comparing the clinical effect of intranasal naloxone at different doses.

OBJECTIVE

The goal of this investigation was to compare the safety, efficacy, and cost of 0.4- versus 2-mg intranasal naloxone for treatment of prehospital opioid overdose.

METHODS

A retrospective, cross-sectional study was performed of 218 consecutive adult patients receiving intranasal naloxone in 2 neighboring counties in Southeast Michigan: one that used a 0.4-mg protocol and one that used a 2-mg protocol. Primary outcomes were response to initial dose, requirement of additional dosing, and incidence of adverse effects. Unpooled, 2-tailed, 2-sample t-tests and χ² tests for homogeneity were performed with statistical significance defined as P <0.05.

RESULTS

There was no statistically significant difference between the 2 populations in age, mass, gender, proportion of exposures suspected as heroin, response to initial dose, required redosing, or total number of doses by any route. The overall rate of adverse effects was 2.1% under the lower-dose protocol and 29% under the higher-dose protocol (P < 0.001). The lower-dose protocol was 79% less costly.

CONCLUSION AND RELEVANCE

Treatment of prehospital opioid overdose using intranasal naloxone at an initial dose of 0.4 mg was equally effective during the prehospital period as treatment at an initial dose of 2 mg, was associated with a lower rate of adverse effects, and represented a 79% reduction in cost.

The Effect of Acute Ethanol Consumption on the Human Retinal Circulation: A Study in Diabetic and Non-Diabetic Subjects

The effects of acute ethanol consumption on retinal haemodynamics and retinal vascular autoregulation to oxygen in the human retinal circulation were studied in 10 diabetic (mean age +/- SD: 38.2 +/- 11.1) and 16 non-diabetic (mean age +/- SD: 32.4 +/- 8.8) subjects. Subjects drank 0.5 g of ethanol, as vodka, per kg of body weight, diluted in sugar-free orange juice. Retinal blood flow was determined using laser Doppler velocimetry and computerised image analysis. The effect of ethanol on oxygen reactivity, as a measure of autoregulation, was also determined after 60% oxygen inhalation. All subjects demonstrated a significant fall in mean arterial blood pressure (control group 3.3%, p = 0.04, diabetic subjects 5.7%, p = 0.05), after ethanol intake. Ethanol caused no significant change in retinal blood flow. Oxygen reactivity was found to be 38.3% (22.4-47.7, median and interquartile range) in the non-diabetic subjects at baseline, and 30.7% (10.8-42.1) after ethanol ingestion. In diabetic subjects, the oxygen reactivity was 33.2% (19.8-46.8) at baseline and 24.5% (21.1-32.1) after ethanol. In this study ethanol did not significantly affect retinal blood flow or impair autoregulation. These results suggest that the retinal circulation may be able to autoregulate despite the presence of ethanol, in contrast to other vascular beds where ethanol changes flow.

A comparison of the position of elite and non-elite riders during competitive show jumping

The purpose of this study was to compare the jumping positions of elite riders (within the top 150 of the British Showjumping rankings) with non-elites (unranked). Video footage of 10 elite and 10 non-elite riders jumping a one stride double combination (a vertical followed by a square oxer) within a 1.20 m competition was analysed. Four angles were measured: the angle between the trunk and the vertical (TRUNKvert), the hip angle (HIP), the angle of the thigh to the horizontal (THIGHhoriz) and the angle of the lower leg to the horizontal (LOWER LEGhoriz). Differences in the angles at five points throughout the double combination and the changes in angles between points were compared using Mann-Whitney U tests. The effect of fence (vertical versus oxer) within groups (elite and non-elite) was also compared. The level of significance was set at P<0.05. HIP angle was significantly smaller on approach to the vertical (P=0.019) and significantly greater when approaching the oxer (P=0.001) for elite riders compared to non-elites. During approach to the oxer compared to the vertical elites had a greater HIP angle (P=0.007), whereas non-elites had smaller HIP (P=0.005) and THIGHhoriz (P=0.005) angles. During suspension, non-elite riders had a greater HIP (P=0.01) over the vertical and smaller LOWER LEGhoriz angle over the oxer (P=0.028) than elite riders. There were significant differences in change in HIP, THIGHhoriz and LOWER LEGhoriz angles between elite and non-elite riders between approach to and suspension over the oxer (P=0.007). During suspension, only elite riders showed an effect of fence with a greater HIP angle (P=0.005) and smaller TRUNKvert angle (P=0.013) over the oxer. Key differences in angles and change in angles exist between elite and non-elite riders. This information is useful in characterising elite rider position and identifying areas of interest for future study.

P5-01-15: The Functional Role of the Estrogen-Regulated Gene GREB1: Characterization of a Novel GREB1 Knockout Mouse Model

Background: Gene regulated in breast cancer 1 (GREB1) was initially discovered in breast cancers as an estrogen-regulated gene that mediates estrogen-stimulated cell proliferation and is a candidate clinical marker for response to endocrine therapy. However, little is known of the functional role of GREB1 protein in normal breast tissue or breast cancers.

Methods: To address this unknown role, our laboratory designed and created a novel Greb1 Knockout Mouse model (C57/bl MEL Greb1 KO). This constitutive model results in the loss of Greb1 mRNA and protein expression in cells where expression of Cre recombinase promotes the cleavage of exon 1 and intron 1 of the gene encoding Greb1. ROSA26 Cre C57/b1 MEL Greb1 KO mice heterozygous for the floxed Greb1 allele were crossed to generate experimental litters. Initial experiments were designed to evaluate if the complete loss of Greb1 expression in offspring homozygous for the floxed Greb1 allele was lethal during gestation. Experimental litters were tail clipped and genotyped using gDNA and genotype-specific PCR.

Results: Offspring homozygous for the floxed Greb1 allele were identified in expected Mendelian ratios with wild type and heterozygous siblings. Loss of Greb1 expression was confirmed using RT-PCR, in situ hybridization and immunoblotting. Loss of both Greb1 alleles was not observed to be lethal during gestation for either male or female pups. Preliminary gross observation of these homozygous KO mice revealed no overt anatomical differences, however, they were 25–30% smaller than their heterozygous and wild-type siblings. Breeding experiments are underway to determine the fertility of crossbred Greb1 homozygous KO mice. Imaging experiments and necropsy with histochemical analysis of tissues will reveal any alteration in architecture and function. These findings will be summarized in this presentation.

Discussion: As GREB1 has been identified as an estrogen-regulated gene involved in breast cancer cell proliferation and a potential target for new therapeutic strategies, it is important to understand the contribution of GREB1 to the differentiation, development and function of normal tissues as well as in breast cancers. Characterization of this novel Greb1 KO mouse model will provide answers to these functional questions surrounding GREB1.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P5-01-15.

Abstract P2-06-18: The Role of GREB1 in Breast Cancer: Identifying GREB1 Binding Proteins and Functional Pathways

Gene regulated in breast cancer 1 (GREB1) was initially discovered in breast cancers as an estrogen-regulated gene that mediates estrogen-stimulated cell proliferation and is a candidate clinical marker for response to endocrine therapy. However, little is known of the functional role of GREB1 protein in breast cancers, its interactive protein partners or the critical cellular pathways where GREB1 is involved. Our team employed a unique two-hybrid system to begin identifying GREB1 binding proteins from normal and cancerous breast cells as well as elucidating the molecular pathways with GREB1 involvement. The Matchmaker Gold Yeast Two-Hybrid System (Clontech Laboratories Inc., Mountain View, CA) was used to identify GREB1 binding proteins from immortalized human mammary epithelial cells (HMECs) and breast cancer cell lines. GREB1 served as a “bait” protein (pGBKT7-GREB1) to screen “prey” proteins generated from cDNA libraries created from immortalized HMECs, GREB1+ (MCF7, T47D) and GREB1- (SKBR3, MDA-464) breast cancer cells lines in yeast (Y187 MATα strain). Protein interactions were stringently screened using GAL4 activation and binding domainmediated reporters including aureobasidin A antibiotic resistance, two nutritional reporters (Histidine and Adenine) and a colorimetric reporter. Prey plasmid DNA, containing cDNA for GREB1 interactive protein candidates, was isolated from selected yeast colonies and sequenced to identify potential GREB1 binding proteins. These individual prey plasmids were subsequently re-introduced to the Y2H system to verify GREB1 interaction and measure the strength of this interaction. Confirmed GREB1 binding protein candidates were further screened using the Matchmaker Mammalian Two-Hybrid System, where interactions between GREB1 and a candidate GREB1-binding protein are verified in mammalian cell background (HEK 293 cells) using a quantitative secreted alkaline phosphatase (SEAP) reporter. This second screen in the mammalian background, unique to this Y2H system, ensures the conformation of GREB1 and the prey protein is similar to their natural state in breast cells and reflects interactions between proteins with greater authenticity than can be achieved in yeast alone. Finally, commercial monoclonal antibodies for GREB1 binding proteins identified using these two-hybrid systems were used to perform confirmatory co-immunoprecipitation experiments with the novel GREB1 monoclonal antibody developed in our laboratory and breast cell line lysates.

Several GREB1 binding proteins, including PTMS, CRABP2, DHTKD1 and SEC23B, were confirmed by yeast and mammalian two-hybrid systems using cDNAs from GREB1+ breast cancer cell lines as well as co-immunoprecipitation assays. Subsequent pathway analysis using public databases (ex: GeneGo, Ingenuity) with GREB1 and these interactive partners suggest that GREB1 may be involved in regulation of gene transcription and cell cycle progression. These preliminary findings substantiate a critical role for GREB1 in breast cancer cell proliferation.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P2-06-18.

Correlation of GREB1 mRNA with protein expression in breast cancer: validation of a novel GREB1 monoclonal antibody

Studies of gene regulated by estrogen in breast cancer 1 (GREB1) have focused on mRNA levels with limited evidence about GREB1 protein expression in normal and breast cancer cells. A monoclonal antibody that recognizes GREB1 protein in breast tissues could be applied to correlate protein expression with established mRNA expression data. A hybridoma expressing a murine monoclonal antibody targeting a 119 amino acid peptide specific to human GREB1 was generated. The novel monoclonal GREB1 antibody (GREB1ab) was validated for use in Western blotting as well as immunohistochemical (IHC) applications. GREB1ab detects a 216 kDa protein corresponding to GREB1 in estrogen receptor alpha (ERalpha+) breast cancer cells as well as ERalpha- breast cancer cells transduced with a GREB1 expression vector. GREB1ab specificity was verified using an ERalpha antagonist to prevent GREB1 induction as well as a silencing siRNA targeting GREB1 mRNA. GREB1ab was further validated for detection of GREB1 by IHC in breast cancer cell lines and breast tissue microarrays (TMA). ERalpha+ cell lines were observed to express GREB1 while ERalpha- cell lines did not express detectable levels of the protein. Using breast cancer tissue whole sections, IHC with the GREB1ab identified protein expression in ERalpha+ breast cancer tissue as well as normal breast tissue, with little GREB1 expression in ERalpha- breast cancer tissue. Furthermore, these data indicate that GREB1 mRNA expression correlates well with protein expression. The novel monoclonal GREB1ab is specific for GREB1 protein. This antibody will serve as a tool for investigations focused on the expression, distribution, and function of GREB1 in normal breast and breast cancer tissues.

Revascularization of cerebral ischemia after previous bilateral extracranial-intracranial bypass procedures

Extracranial-intracranial (EC-IC) bypass grafting procedures were specially designed for treatment of bilateral internal carotid artery occlusion. When performed in an expeditious manner, EC-IC bypass procedures have produced effective and durable results, despite the recent disfavor given to this procedure. This communication reports a 68-year-old white man who developed generalized cerebral ischemia manifested as confusion, incoherence, disorientation, ataxia, and numerous episodes of syncope daily. A cerebral angiogram revealed bilateral external carotid arteries and left solitary vertebral artery critical stenosis. Transcranial Doppler study demonstrated reduction of cerebral and vertebral-basilar perfusion. However, the patient's EC-IC bypass graft had remained patent since 1985. The patient's recurrent symptoms of global ischemia and syncope resolved after carotid endarterectomy, vein patch external carotid artery, and vertebral-to-common carotid artery transposition. This report reiterates the value of the EC-IC bypass procedure and presents the surgical management of symptomatic external carotid and vertebral artery stenosis in patients after EC-IC bypass procedures.

Effect of maternal ethanol consumption on maternal and fetal calcium metabolism

Alcohol consumption can have deleterious effects on both adult and developing bone. The mechanism(s) by which alcohol affects bone, however, is unknown. This study investigated the possibility that alcohol affects bone by alterations in calcium (Ca) metabolism. Female rats were fed lab chow ad libitum (C, Control) or a liquid diet with (E, Ethanol) or without (PF, Pair-Fed) ethanol. After 2 weeks on their respective diets, the rats were bred and the experimental diets continued throughout gestation. Blood (dams only) and tissue were collected on day 21 of gestation. The Ca content of maternal bone showed a trend toward a decrease in E and PF compared with C dams. Ionic Ca (iCa) levels were decreased in the blood of the E compared with PF and C dams. Serum parathyroid hormone levels were elevated in the E compared with C dams, consistent with the low iCa levels. Serum levels of 1,25(OH)2D, however, were elevated only in the PF dams. Mean fetal body weight and fetal skeletal ossification were reduced in the E compared with PF and C groups, but no group differences were found in fetal Ca content. These results indicate that maternal ethanol consumption compromised the ability of the dam to regulate her blood iCa levels, possibly partly due to a failure to increase 1,25(OH)2D levels. The delays in skeletal development observed in the ethanol exposed fetuses, however, do not appear to result from impaired placental Ca transfer.

Fetal ethanol exposure alters pituitary-adrenal sensitivity to dexamethasone suppression

The present study investigated the hypothesis that a deficit in feedback inhibition of the hypothalamic-pituitary-adrenal (HPA) axis may underlie the hormonal hyperresponsiveness seen in fetal ethanol-exposed rats. Male and female Sprague-Dawley rats from prenatal ethanol (E), pair-fed (PF) and ad lib-fed control (C) treatment groups were tested in adulthood. The effects of dexamethasone (DEX) blockade on basal and stress corticosterone (CORT) levels and stress adrenocorticotropin (ACTH) levels were examined over a 36-h period. Stress CORT and ACTH levels after DEX administration at the trough (AM) and peak (PM) of the CORT circadian rhythm were compared. DEX administration significantly suppressed both resting and stress levels of CORT and ACTH in all animals, regardless of prenatal treatment. Importantly, E animals did not differ from PF and C animals in basal CORT. However, E males and females had significantly higher stress levels of CORT and/or ACTH than PF and C animals, and further, showed differential responsiveness following DEX administration depending on the time of day when testing occurred. At the trough of the CORT circadian rhythm. E males did not differ from PF and C males, whereas E females had increased stress levels of CORT compared to PF and C females. In contrast, at the peak of the circadian rhythm, E males showed increased stress levels of CORT but not ACTH, whereas E females showed increased stress levels of both CORT and ACTH compared to males and females in respective control groups. These data support the hypothesis that E animals may exhibit deficits in HPA feedback inhibition compared to controls and suggest a sex-specific difference in sensitivity of the mechanism underlying HPA hyperresponsiveness.

The acute effect of smoking on retinal blood flow in subjects with and without diabetes

PURPOSE

This study investigates the effect of smoking on retinal blood flow and autoregulation in smokers with and without diabetes.

METHODS

Eleven patients with diabetes mellitus and ten control subjects were investigated. Laser Doppler velocimetry and retinal photography were used to measure retinal blood flow; vascular autoregulation was assessed with 60% oxygen breathing. These procedures were performed before and after smoking.

RESULTS

Both groups demonstrated a significant increase in heart rate and systolic and diastolic blood pressure (P < 0.01). In both groups, smoking caused a significant decrease in retinal blood flow: 9.6% +/- 12% in the control group (P < 0.05) and 16.4% +/- 13.8% in the diabetic group (P < 0.01). The pre-smoking oxygen reactivity was comparable in both groups (P = 0.5); 27.9% +/- 3.3% and 32.0% +/- 5.0% in the control and diabetic groups, respectively. After smoking, oxygen reactivity was reduced significantly in the control group to 9.6% +/- 4.0% (P = 0.002) and eliminated in the patients with diabetes.

CONCLUSIONS

This study shows that smoking reduces retinal blood flow and the ability of the retinal vessels to autoregulate to hyperoxia; these effects are likely to be due to the vasoconstrictive effect of nicotine, which is mediated through activation of the sympathetic system. Smoking has been shown previously to increase the level of carboxyhemoglobin, thereby reducing the oxygen-carrying capacity of blood, which, when associated with the reduced blood flow shown in the current study, may reduce retinal oxygen delivery. Hypoxia is a major factor in the progression of diabetic retinopathy; therefore, smoking may exert a detrimental influence, which may be compounded further by the additional effect smoking has on autoregulation.

Soluble and membrane-bound TNF-alpha are involved in the cytotoxic activity of B cells from tumor-bearing mice against tumor targets

Splenic B cells from BALB/c mice bearing mammary adenocarcinomas are capable of performing Ab-dependent cellular cytotoxicity. Effector-target conjugation after 18 h results in minimal cytoplasmic damage, whereas extensive nuclear disintegration is observed. To determine whether splenic B cells from tumor-bearing mice can effect direct cytotoxicity against tumor cells, L929 and WEHI 164 cells were used as targets. B lymphocytes from tumor-bearing mice, but not from normal animals, were capable of lysing these two types of tumor cells. However, only a low level of cytotoxicity could be detected when the nontumorigenic 3T3 cells were used as targets. To elucidate the mechanism of cytotoxicity of these killer B cells, RNase protection assays were performed using perforin, granzyme A, TNF-alpha, and lymphotoxin probes. No perforin, granzyme A, or lymphotoxin RNA could be detected in purified preparations of B cells from normal and tumor-bearing mice. B cells from normal mice did not have TNF-alpha RNA. In contrast, B cells from tumor bearers expressed TNF-alpha RNA. TNF-alpha could be detected in supernatants from both unstimulated and stimulated tumor bearers' splenic B cells, as measured by ELISA, and its lytic activity was neutralized by anti-TNF-alpha Ab. Western blots revealed the presence of TNF-alpha on the surface of the killer B cells. Paraformaldehyde-fixed B cells from tumor-bearing mice but not from normal animals were able to lyse TNF-alpha-sensitive tumor targets. This cytotoxicity was neutralized by anti-TNF-alpha Ab. These results suggest that TNF-alpha in soluble and membrane-bound forms may be involved in the mechanism of cytotoxicity exerted by B cells from tumor-bearing mice.

Soluble and membrane-bound TNF-alpha are involved in the cytotoxic activity of B cells from tumor-bearing mice against tumor targets

Splenic B cells from BALB/c mice bearing mammary adenocarcinomas are capable of performing Ab-dependent cellular cytotoxicity. Effector-target conjugation after 18 h results in minimal cytoplasmic damage, whereas extensive nuclear disintegration is observed. To determine whether splenic B cells from tumor-bearing mice can effect direct cytotoxicity against tumor cells, L929 and WEHI 164 cells were used as targets. B lymphocytes from tumor-bearing mice, but not from normal animals, were capable of lysing these two types of tumor cells. However, only a low level of cytotoxicity could be detected when the nontumorigenic 3T3 cells were used as targets. To elucidate the mechanism of cytotoxicity of these killer B cells, RNase protection assays were performed using perforin, granzyme A, TNF-alpha, and lymphotoxin probes. No perforin, granzyme A, or lymphotoxin RNA could be detected in purified preparations of B cells from normal and tumor-bearing mice. B cells from normal mice did not have TNF-alpha RNA. In contrast, B cells from tumor bearers expressed TNF-alpha RNA. TNF-alpha could be detected in supernatants from both unstimulated and stimulated tumor bearers' splenic B cells, as measured by ELISA, and its lytic activity was neutralized by anti-TNF-alpha Ab. Western blots revealed the presence of TNF-alpha on the surface of the killer B cells. Paraformaldehyde-fixed B cells from tumor-bearing mice but not from normal animals were able to lyse TNF-alpha-sensitive tumor targets. This cytotoxicity was neutralized by anti-TNF-alpha Ab. These results suggest that TNF-alpha in soluble and membrane-bound forms may be involved in the mechanism of cytotoxicity exerted by B cells from tumor-bearing mice.

p120, a novel substrate of protein tyrosine kinase receptors and of p60v-src, is related to cadherin-binding factors beta-catenin, plakoglobin and armadillo

A novel protein tyrosine kinase (PTK) substrate, p120, has been previously implicated in ligand-induced signaling through the epidermal growth factor, platelet-derived growth factor and colony-stimulating factor 1 receptors, and in cell transformation by p60v-src. We have isolated a near full-length cDNA encoding murine p120. The encoded protein lacks significant homology with any reported protein, but it contains four copies of an imperfect 42 amino acid repeat that occurs 12.5 times in the protein encoded by Drosophila armadillo (arm), and its direct homologs, human plakoglobin (plak) and Xenopus laevis beta-catenin (beta-cat). The presence of this motif implies that p120 may share at least one aspect of its function with the arm protein and its homologs.

Role of tumor-derived cytokines on the immune system of mice bearing a mammary adenocarcinoma. II. Down-regulation of macrophage-mediated cytotoxicity by tumor-derived granulocyte-macrophage colony-stimulating factor

Peritoneal elicited macrophages (PEM) from mammary tumor-bearing mice have a decreased capacity to become cytotoxic against syngeneic, allogeneic, and xenogeneic target cells upon in vitro stimulation with LPS, as compared with PEM of normal mice. A regulatory mechanism other than PG release is suggested because the addition of both indomethacin and LPS to macrophage cultures from tumor-bearing mice caused no changes in their cytotoxic capability. Because tumor products have been implicated in the down-regulation of immune responses, we investigated whether pretreatment with supernatants from the tumor cell line DA-3, derived from the in vivo mammary adenocarcinoma D1-DMBA-3, affects the cytolytic capacity of macrophages. This treatment inhibits, in a dose-dependent fashion, the ability of stimulated normal PEM to kill target cells. Partial purification of DA-3 cell line supernatant showed that most of the inhibitory activity was exerted by factors with a molecular mass greater than 10 kDa and less than 30 kDa. However, slight inhibition could also be observed with fractions containing molecules less than 10 kDa. The data suggest that more than one factor released by the mammary tumor cells may be involved in the down-regulation of macrophage-mediated cytotoxicity. Because the DA-3 cells constitutively produce granulocyte-macrophage CSF (GM-CSF), which has a molecular mass of 27 kDa, we pretreated PEM from normal mice in vitro with rGM-CSF for 24 h. This resulted in a dose-dependent decrease in their capacity to kill tumor target cells upon LPS stimulation. Furthermore, PEM from normal mice injected with rGM-CSF for 25 days displayed a profound decrease in their cytolytic ability against DA-3 targets upon in vitro stimulation with increasing amounts of LPS. The pretreatment of PEM from normal mice with a combination of DA-3 cell supernatants and specific anti-GM-CSF partially neutralized the inhibitory effect of the DA-3 supernatant on macrophage tumoricidal capability. These results indicate that tumor-derived GM-CSF is an important factor involved in the decreased macrophage cytotoxicity during mammary adenocarcinoma progression.

Role of tumor-derived cytokines on the immune system of mice bearing a mammary adenocarcinoma. II. Down-regulation of macrophage-mediated cytotoxicity by tumor-derived granulocyte-macrophage colony-stimulating factor

Peritoneal elicited macrophages (PEM) from mammary tumor-bearing mice have a decreased capacity to become cytotoxic against syngeneic, allogeneic, and xenogeneic target cells upon in vitro stimulation with LPS, as compared with PEM of normal mice. A regulatory mechanism other than PG release is suggested because the addition of both indomethacin and LPS to macrophage cultures from tumor-bearing mice caused no changes in their cytotoxic capability. Because tumor products have been implicated in the down-regulation of immune responses, we investigated whether pretreatment with supernatants from the tumor cell line DA-3, derived from the in vivo mammary adenocarcinoma D1-DMBA-3, affects the cytolytic capacity of macrophages. This treatment inhibits, in a dose-dependent fashion, the ability of stimulated normal PEM to kill target cells. Partial purification of DA-3 cell line supernatant showed that most of the inhibitory activity was exerted by factors with a molecular mass greater than 10 kDa and less than 30 kDa. However, slight inhibition could also be observed with fractions containing molecules less than 10 kDa. The data suggest that more than one factor released by the mammary tumor cells may be involved in the down-regulation of macrophage-mediated cytotoxicity. Because the DA-3 cells constitutively produce granulocyte-macrophage CSF (GM-CSF), which has a molecular mass of 27 kDa, we pretreated PEM from normal mice in vitro with rGM-CSF for 24 h. This resulted in a dose-dependent decrease in their capacity to kill tumor target cells upon LPS stimulation. Furthermore, PEM from normal mice injected with rGM-CSF for 25 days displayed a profound decrease in their cytolytic ability against DA-3 targets upon in vitro stimulation with increasing amounts of LPS. The pretreatment of PEM from normal mice with a combination of DA-3 cell supernatants and specific anti-GM-CSF partially neutralized the inhibitory effect of the DA-3 supernatant on macrophage tumoricidal capability. These results indicate that tumor-derived GM-CSF is an important factor involved in the decreased macrophage cytotoxicity during mammary adenocarcinoma progression.

Equine herpesvirus abortion in Australia 1977 to 1982

Until 1977 no case of abortion caused by equine herpesvirus 1 (EHV1) had been recorded in Australia although the virus, called equine rhinopneumonitis virus, had been known to have been present at least since 1962. Outbreaks of EHV1 abortion occurred in New South Wales in 1977 and in 1981. Sporadic cases of EHV1 abortion had been confirmed in some parts of Australia each year since 1975. It was concluded that an abortigenic subtype of EHV1 had been introduced to Australia in 1977 and that the previously endemic respiratory subtype occasionally caused abortion. Virus isolation in a variety of cell cultures and histopathological examination of tissue were shown to be satisfactory methods of diagnosis of EHV1 abortion. Lung proved to be the specimen of choice. Slight serological differences between "abortigenic" and "respiratory" subtypes of EHV1 were found in cross neutralisation tests. A serological survey of 219 Sydney horses of various ages revealed that most yearlings had already acquired neutralising antibody to both subtypes.

Canine parvovirus infection in Australia during 1980

A questionnaire sent to all veterinary practitioners in Australia and many in New Zealand asking for details of their experience with canine parvovirus infections in 1980 elicited the following information. In 1980 explosive outbreaks of disease occurred in most parts of Australia. There was no obvious pattern of spread over the continent as a whole. In many cases outbreaks in country areas occurred after dog shows. Canine parvovirus enteritis affected all age groups with an overall mortality of 16 per cent. While the death rate in the young was high, most dogs responded well to fluid therapy. Canine parvovirus did not appear to be associated with clinical entities other than gastroenteritis and myocarditis. No connection with reproductive problems was established. Killed canine parvovirus vaccines were used extensively after the initial release for sale in July 1980. The vaccines appeared to be safe and effective at least in the short term. Problems arose only in vaccination of very young animals.

Computer-assisted interpretation of clinical EEGs

A multivariate pattern recognition technique has been developed, to distinguish the EEGs of patients with cerebral pathology from those of normal controls and to localize any abnormalities detected. Two methods of feature extraction have been used, power spectral density and slope descriptor analysis, together with various types of feature compression. These techniques have been evaluated on EEGs from 63 patients with proven pathology. Spectral analysis proved more reliable than slope descriptor analysis and predicted the site of cerebral pathology more accurately than did visual assessment of the EEGs. This apparent improvement over the diagnostic reliability of visual analysis in considered to justify further development and evaluation of this technique.

Neonatal intensive care and radiation

Radiography plays an important role in a neonatal intensive care nursery. Diagnostic radiation was measured in 96 newborns. Mean exposure per neonate was 68.1 milliroentgens (mR) (SD = 132.7) with a median exposure per neonate of 28 mR. Radiation received by neonates was low, but further studies are needed to show the safety of radiation or its delayed effects. The measurement of radiation is simple, and routine radiation recording can prove useful in future evaluations of this high-risk population.