Aneuploidy in dizygotic twin sheep detected using genome-wide single nucleotide polymorphism data from two commonly used commercial vendors.

Early detection of karyotype abnormalities, including aneuploidy, could aid producers in identifying animals which, for example, would not be suitable candidate parents. Genome-wide genetic marker data in the form of single nucleotide polymorphisms (SNPs) are now being routinely generated on animals. The objective of the present study was to describe the statistics that could be generated from the allele intensity values from such SNP data to diagnose karyotype abnormalities; of particular interest was whether detection of aneuploidy was possible with both commonly used genotyping platforms in agricultural species, namely the Applied BiosystemsTM AxiomTM and the Illumina platform. The hypothesis was tested using a case study of a set of dizygotic X-chromosome monosomy 53,X sheep twins. Genome-wide SNP data were available from the Illumina platform (11 082 autosomal and 191 X-chromosome SNPs) on 1848 male and 8954 female sheep and available from the AxiomTM platform (11 128 autosomal and 68 X-chromosome SNPs) on 383 female sheep. Genotype allele intensity values, either as their original raw values or transformed to logarithm intensity ratio (LRR), were used to accurately diagnose two dizygotic (i.e. fraternal) twin 53,X sheep, both of which received their single X chromosome from their sire. This is the first reported case of 53,X dizygotic twins in any species. Relative to the X-chromosome SNP genotype mean allele intensity values of normal females, the mean allele intensity value of SNP genotypes on the X chromosome of the two females monosomic for the X chromosome was 7.45 to 12.4 standard deviations less, and were easily detectable using either the AxiomTM or Illumina genotype platform; the next lowest mean allele intensity value of a female was 4.71 or 3.3 standard deviations less than the population mean depending on the platform used. Both 53,X females could also be detected based on the genotype LRR although this was more easily detectable when comparing the mean LRR of the X chromosome of each female to the mean LRR of their respective autosomes. On autopsy, the ovaries of the two sheep were small for their age and evidence of prior ovulation was not appreciated. In both sheep, the density of primordial follicles in the ovarian cortex was lower than normally found in ovine ovaries and primary follicle development was not observed. Mammary gland development was very limited. Results substantiate previous studies in other species that aneuploidy can be readily detected using SNP genotype allele intensity values generally already available, and the approach proposed in the present study was agnostic to genotype platform.

Isolation of subtelomeric sequences of porcine chromosomes for translocation screening reveals errors in the pig genome assembly.

Balanced chromosomal aberrations have been shown to affect fertility in most species studied, often leading to hypoprolificacy (reduced litter size) in domestic animals such as pigs. With an increasing emphasis in modern food production on the use of a small population of high quality males for artificial insemination, the potential economic and environmental costs of hypoprolific boars, bulls, rams etc. are considerable. There is therefore a need for novel tools to facilitate rapid, cost-effective chromosome translocation screening. This has previously been achieved by standard karyotype analysis; however, this approach relies on a significant level of expertise and is limited in its ability to identify subtle, cryptic translocations. To address this problem, we developed a novel device and protocol for translocation screening using subtelomeric probes and fluorescence in situ hybridisation. Probes were designed using BACs (bacterial artificial chromosomes) from the subtelomeric region of the short (p-arm) and long (q-arm) of each porcine chromosome. They were directly labelled with FITC or Texas Red (p-arm and q-arm respectively) prior to application of a 'Multiprobe' device, thereby enabling simultaneous detection of each individual porcine chromosome on a single slide. Initial experiments designed to isolate BACs in subtelomeric regions led to the discovery of a series of incorrectly mapped regions in the porcine genome assembly (from a total of 82 BACs, only 45 BACs mapped correctly). Our work therefore highlights the importance of accurate physical mapping of newly sequenced genomes. The system herein described allows for robust and comprehensive analysis of the porcine karyotype, an adjunct to classical cytogenetics that provides a valuable tool to expedite efficient, cost effective food production.

Characterization of an X-chromosomal non-mosaic monosomy (59, X0) dairy heifer detected using routinely available single nucleotide polymorphism genotype data.

Evidence exists from a range of species on the impact of karyotype abnormalities on reproductive performance. Despite this, cytogenetic analyses of cattle, especially females, are not routinely undertaken. Genome-wide single nucleotide polymorphism (SNP) genotype data are now, however, routinely being generated in many species globally at a relatively low cost. The objective of the present study was to evaluate the potential of routinely available SNP genotype data to identify sex-chromosome aberrations using X chromosome monosomy 59,X0 as a case study for illustration. A single 2.5-yr old Holstein-Friesian heifer was detected with a mean allelic intensity of SNP on the X chromosome almost 17 standard deviations less than the mean of other genotyped females ( = 103,326). Following cytogenetic analysis (10 replicates by karyotyping and a further 140 by FISH), the female was deduced to be a non-mosaic 59,X0. The female had never produced a calf and, although gross examination revealed no physical abnormalities, she was smaller in size than expected based on her breed and age. Given the age of the animal at slaughter, the uterus and uterine tubes appeared immature and inactive. The oviduct appeared normal while the single ovary present contained a markedly reduced number of follicles. There was, however, some evidence of prior ovulation and formation of corpora lutea. The approach proposed in the present study to identify allosome aneuploidy from routinely available genotype data can be used to screen for such abnormalities at no additional cost to the breeder or producer.

Failed prehospital intubations: an analysis of emergency department courses and outcomes.

OBJECTIVE: To examine the reasons for failed prehospital endotracheal intubation (ETI) and to identify how the airway was subsequently managed in the emergency department (ED). METHODS: Data were collected from January to December 1998 for a county-wide paramedic system. Failed prehospital ETIs and perceived reasons for failure were identified. Subsequent ED airway management was reviewed. RESULTS: During the study period there were 13,112 patient contacts resulting in ETI attempts on 592 patients, of whom 536 (90.5%) were successfully intubated. Of the 56 failed field intubations, 49 (87.5%) had ED charts available for review. Endotracheal intubation failure was associated with inadequate relaxation in 24 (49%), difficult anatomy in ten (20%), and obstruction in five (10%). Successful ETI was achieved in the ED in 42 cases (86%). Twenty cases (41%) were facilitated by rapid-sequence intubation (RSI) in the ED. For those with incomplete relaxation in the field, 13 of 24 (54%) were intubated in the ED using RSI. Factors associated with the use of ED RSI include attempted prehospital nasotracheal intubation or attempted prehospital midazolam-facilitated intubation (p < 0.001). The predicted need for RSI in this prehospital system is approximately 3.9%. In eight cases, three or more ETI attempts or the use of rescue airways was required in the ED. The predicted minimum incidence of "truly difficult" intubation in this system is approximately 0.8-1.6%. CONCLUSIONS: Paramedic intubation failures result from a variety of factors. Less than half of field intubation failures were remedied in the ED by the use of neuromuscular-blocking agents. A similar number were intubated without the use of RSI. A fraction of failed field ETIs may have resulted from inadequate operator training or experience. A small percentage of field patients were "truly difficult" and required advanced resources in the ED to facilitate airway management. Medical directors should be cognizant of the numerous factors affecting intubation performance when designing and implementing approaches to difficult prehospital airways.

Patient status and time to intubation in the assessment of prehospital intubation performance.

UNLABELLED: Assessment of paramedic endotracheal intubation (ETI) performance often does not account for varied clinical conditions or the time required to complete the procedure. OBJECTIVE: To demonstrate the utility of patient status and time to intubation (TTI) for evaluating prehospital ETI performance. METHODS: Paramedic charts were reviewed for the period January-December 1998. Patient clinical status was defined as cardiac arrest (absence of perfusing rhythm) or non-cardiac arrest (presence of perfusing rhythm). Method, route, and success of ETI were noted. The TTI was determined as the elapsed time from on-scene arrival to securing of the endotracheal tube. Time elapsed from on-scene arrival to emergency department arrival was noted for instances of failed ETI. Statistical analysis was performed using chi-square and survival analysis (Kaplan-Meier estimator). RESULTS: Computer records were available for 26,026 patient contacts. Of 893 documented ETI attempts, 771 (86%) were successful. The ETI success rate was significantly higher (p<0.001) for cardiac arrests (551 of 591, 93.2%) than for non-cardiac arrests (220 of 302, 72.9%). Median TTIs were 5 minutes (95% CI: 5, 5) for cardiac arrests and 17 minutes (95% CI: 14, 20) for non-cardiac arrests; this difference was significant (p<0.001). For non-cardiac arrests, ETI success was significantly (p = 0.002) higher for orotracheal intubation (OTI) (168 of 214, 78.5%) than for nasotracheal intubation (NTI) (52 of 88, 59.1%). Median TTIs were 15 minutes (95% CI: 13, 17) for OTI and 25 minutes (95% CI: 23, 27) for NTI; this difference was significant (p = 0.002). For non-cardiac arrests, the difference i

The use of diltiazem for treating rapid atrial fibrillation in the out-of-hospital setting.

STUDY OBJECTIVE: We sought to evaluate the use of intravenous diltiazem for treatment of rapid atrial fibrillation or flutter (RAF) in the out-of-hospital setting. METHODS: This study is a retrospective review of data with historical control subjects. Data were drawn from out-of-hospital patients reported to a statewide paramedic system who presented with atrial fibrillation or flutter and a ventricular response rate (VRR) of 150 beats/min or greater. The intervention (diltiazem) group included patients who received diltiazem during a 9-month period in 1999. The control group included patients from 1998 who did not receive diltiazem. Patients who were intubated or underwent cardioversion were omitted. Therapeutic response was defined as the occurrence of change to sinus rhythm, reduction of VRR to 100 beats/min or less, or reduction of baseline VRR by 20% or greater. Data were analyzed by using the chi(2) test, the Student's t test, and odds ratios (ORs). A Bonferroni adjusted P value of.005 was used to define statistical significance. RESULTS: Forty-three patients receiving diltiazem and 27 control subjects were included in the study. The mean total diltiazem dose was 19.8 mg (95% confidence interval 17.8 to 21.8). The diltiazem and control groups did not significantly differ with respect to age; sex; history of atrial fibrillation; prior use of digitalis, beta-blockers, or calcium channel blockers; concurrent out-of-hospital therapies; or baseline VRR or systolic blood pressure (P =.09 to 1.00). The difference in VRR reduction between the diltiazem and control groups was 38 beats/min (95% confidence interval 24 to 52); this difference was statistically significant (P <.001). The mean percentage reduction of VRR in the diltiazem group was -33.1%. The difference in systolic blood pressure change between the diltiazem and control groups was not statistically significant (P =.17). The diltiazem group had a higher prevalence of achieving VRR reduction to 100 beats/min or less than did the control group (OR 22.6; P <.001), of achieving a VRR reduction of 20% or greater (OR 19.3; P <.001), and of achieving overall therapeutic response (OR 19.3; P <.001). Few changed to sinus rhythm in either group (estimated OR 6.3; P =.15). No patients in the diltiazem group required treatment for hypotension, endotracheal intubation, resuscitation from cardiac arrest, or emergency treatment of unstable dysrhythmias. CONCLUSION: The effects of diltiazem on RAF can be appreciated within the constraints of the out-of-hospital environment. Diltiazem should be considered as a viable field therapy for rate control of RAF.

Paramedic success rate for blind nasotracheal intubation is improved with the use of an endotracheal tube with directional tip control.

STUDY OBJECTIVES: Blind nasotracheal intubation (BNTI) is used to secure the airway in patients who are spontaneously breathing. The success rate for BNTI is often lower than for orotracheal intubation. We conducted this study to determine whether the use of an endotracheal tube (ETT) capable of directional tip control can improve the BNTI success rate. METHODS: This prospective, experimental study was conducted by a state emergency medical services agency during 1997, 1998, and 1999. Consecutive patients undergoing attempted BNTI or orotracheal intubation were included. Five paramedic units were trained to use an ETT with triggeractivated distal tip directional control for BNTIs (intervention group). Ten units used conventional ETTs for BNTIs and served as concurrent controls (control group). Subjects in the 2 groups were enrolled concurrently with nonrandomized allocation based on the agency providing service. An intubation attempt was defined by tube passage, and success was defined as confirmed endotracheal placement. RESULTS: A total of 219 BNTIs were studied (141 in the control group and 78 in the intervention group). BNTI was successful in 82 (58%) of 141 cases using conventional ETTs, and in 56 (72%) of 78 cases using directional tip control (P =.04). The overall success rate was 63%. CONCLUSION: Use of ETTs with distal directional control is associated with a higher success rate for BNTI than conventional ETTs. Use of ETTs with directional tip control significantly improves the success rates for BNTIs.

The use of emergency medical dispatch protocols to reduce the number of inappropriate scene responses made by advanced life support personnel.

OBJECTIVES: To determine whether implementation of an emergency medical dispatch (EMD) system would reduce the rate of inappropriate advanced life support (ALS) utilization, and enable more accurate identification of those patients requiring ALS care. METHODS: An emergency medical services (EMS) site providing basic life support (BLS) and ALS care to a population of 200,000 served as the study site for calendar year 1996. This study compared the prospective identification of patients as ALS or BLS using EMD with that using chief complaint-based dispatch criteria. Each patient served as his or her own control. The ALS or BLS priority was assigned using both chief complaint and EMD criteria. Chief complaint-based dispatching meant that all patients with preestablished chief complaints received ALS without further triage questions, while EMD allowed the dispatchers to question callers using a scripted set of questions. The outcome measures included the number of calls categorized as ALS or BLS, the number of calls cancelled by BLS, and the number of ALS calls released to BLS care. Yates-corrected chi-square was used for statistical analysis. RESULTS: There were 11,174 patients enrolled. The use of EMD was associated with a significant decrease in the proportion of calls designated as ALS (44.7% vs 55.8%, p < 0.0001), as well as a significant decrease in the number of ALS responses cancelled by BLS (9.2% vs 23.8%, p < 0.0001) and patients released to BLS by medical control (4.7% vs 7.3%, p < 0.0001). CONCLUSIONS: Implementation of an EMD system significantly decreased inappropriate ALS dispatching, as defined by decreased rate of ALS cancellations and BLS releases. Further study is needed to see whether other EMD dispatch models may further refine ALS dispatch.

The utilization of midazolam as a pharmacologic adjunct to endotracheal intubation by paramedics.

OBJECTIVE: Pharmacologic agents have been used in the prehospital setting for facilitating endotracheal intubation (ETI). The purpose of this study was to determine the utility of intravenous midazolam for prehospital patients who require pharmacologic relaxation to facilitate ETI. METHODS: Data were reviewed retrospectively using paramedic charts from an eight-month period for a three-county state EMS system. RESULTS: There were 26,133 paramedic dispatches during the study period. Six hundred eighty-three ETIs were attempted, including 72 midazolam-facilitated intubations (MFIs). The most common indications for MFI were "clenched teeth," "gag," and "combativeness." Successful MFI was achieved in 45 of 72 cases (62.5%). Midazolam-facilitated intubation was less successful for trauma patients (41.2%) than for medical patients (69.1 %) (p = 0.04). Of the 58 failed conventional ETIs that occurred during the study period, 25 (43.1%) were identified as having one or more indications for the use of MFI. Although the use of intravenous midazolam was effective in facilitating ETI, a high MFI failure rate (37.5%) was noted. CONCLUSION: Although it is of limited efficacy, MFI is underutilized and should be considered by medical direction as a pharmacologic adjunct to ETI in selected field patients.

EMS systems: foundations for the future.

Emergency medical services (EMS) occupy a unique position in the continuum of emergency health care delivery. The role of EMS personnel is expanding beyond their traditional identity as out-of-hospital care providers, to include participation and active leadership in EMS administration, education, and research. With these roles come new challenges, as well as new responsibilities. This paper was developed by the SAEM EMS Task Force and provides a discussion of these new concepts as well as recommendations for the specialty of emergency medicine to foster the continued development of all of the potentials of EMS.

The range of medication storage temperatures in aeromedical emergency medical services.

OBJECTIVES: The United States Pharmacopoeia (USP) recommends that medication storage temperatures should be maintained between 15 degrees C and 30 degrees C (59 degrees F to 86 degrees F). Concerns have been raised that storage temperatures in EMS may deviate from this optimal range, predisposing drugs to degradation. This study was conducted to determine whether temperatures inside the drug box carried by paramedics aboard a helicopter remained within the range. METHODS: The Aviation Section, with a paramedic on board, utilizes two helicopters and conducts approximately 80 patient care flights per month. A dual-display indoor/outdoor thermometer with memory was used to measure the highest and lowest temperatures during each shift. The thermometer was kept with medications in a nylon drug bag, which remained on the helicopter except when needed for patient care. Ambient temperature measurements at the location of the helicopter base were obtained from the National Climatic Data Center. Temperature ranges were recorded during day shift (8 AM to 4 PM) and night shift (4 PM to 12 AM) during the winter from December 1, 1995, to March 13, 1996, and summer from June 17, 1996, to September 14, 1996. Statistical analysis was performed using chi-square and the Bonferroni-adjusted t-test. RESULTS: Compared with the winter day period, the winter night period had lower minimum (13.2 degrees C vs 14.7 degrees C, p = 0.003) and maximum (20.3 degrees C vs 21.2 degrees C, p = 0.02) temperatures. Both were below the USP minimum. The summer day period had higher maximum temperatures than the summer night period (31.2 degrees C vs 27.6 degrees C, p = 5 x 10(-9)). The mean daytime summer maximum exceeded the USP upper limit. Storage temperatures outside of the USP range were observed during 49% of winter days, 62% of winter nights, 56% of summer days, and 27% of summer nights. There was a significant tendency for summer days (p = 8 x 10(-8)) and winter nights (p = 0.009) to be outside of the acceptable range. There was moderate correlation between ambient and drug box temperatures (r2 = 0.49). CONCLUSIONS: Medications stored aboard an EMS helicopter are exposed to extremes of temperature, even inside a drug bag. Measures are needed to attenuate storage temperature fluctuations aboard aeromedical helicopters.

Thrombolytic therapy for acute ischemic stroke: why the majority of patients remain ineligible for treatment.

STUDY OBJECTIVES: Thrombolytic therapy has been advocated as an effective treatment for acute ischemic stroke. In an attempt to promote maximum benefit while reducing the risk of hemorrhagic complications, numerous exclusions to the use of thrombolytic therapy for acute ischemic stroke have been promulgated. This study was conducted to identify the number of acute ischemic stroke patients eligible for thrombolytic therapy and to determine the reasons those deemed ineligible were excluded. METHODS: This observational study was conducted from September 15, 1996, to May 1, 1997, at an emergency department with an annual census of 70,000. Patients with a chief complaint suggestive of acute ischemic stroke were categorized as "eligible" if thrombolytic therapy was not contraindicated and could be initiated within 3 hours of symptom onset. Patients were deemed "ineligible" if the time to thrombolytic therapy would have exceeded 3 hours, or if other specific contraindications to thrombolytic therapy were present. For all categories, 95% confidence intervals (95% CI) were determined. RESULTS: Of the 214 patients with acute ischemic stroke who were screened, 6 (2.8%+/-2.2%) were eligible. Ninety-five patients (44%+/-7%) were excluded solely on the basis of the time interval from onset of symptoms to eligibility for thrombolytic therapy exceeding 3 hours. Other common reasons for exclusion included resolution of symptoms in 31 patients (14%+/-4%), intracranial hemorrhage as determined by head computed tomography in 22 (10%+/-4%), and minor symptoms in 20 (9%+/-4%). CONCLUSION: The majority of acute ischemic stroke patients do not meet accepted criteria for thrombolytic therapy. Most are ineligible because of delays in obtaining treatment. Strategies should be devised to reduce the time to treatment if thrombolytic therapy is to achieve widespread use in the treatment of acute ischemic stroke.

Rating threat mitigators: faith in experts, governments, and individuals themselves to create a safer world.

This research explores public judgments about the threat-reducing potential of experts, individual behavior, and government spending. The data are responses of a national sample of 1225 to mail surveys that include measures of several dimensions of public judgments about violent crime, automobile accidents, hazardous chemical waste, air pollution, water pollution, global warming, AIDS, heart disease, and cancer. Beliefs about who can best mitigate threats are specific to classes of threats. In general, there is little faith that experts can do much about violent crime and automobile accidents, moderate faith in their ability to address problems of global warming, and greater expectations for expert solutions to the remaining threats. People judge individual behavior as effective in reducing the threats of violent crime, AIDS, heart disease, and automobile accidents but less so for the remaining threats. Faith in more government spending is highest for AIDS and the other two health items, lowest for the trio of violent crime, automobile accidents, and global warming, and moderate for the remaining threats. For most threats, people are not distributed at the extremes in judging mitigators. Strong attitudinal and demographic cleavages are also lacking, although some interesting relationships occur. This relative lack of sharp cleavages and the generally moderate opinion indicate ample opportunity for public education and risk communication.

Emergency medical services transport of patients with headache: mode of arrival may indicate serious etiology.

OBJECTIVE: To determine whether mode of arrival is associated with seriousness of etiology and use of diagnostic testing in patients treated in the emergency department for headache. METHODS: This observational, retrospective study was conducted by consecutive review of the records of patients presenting to the emergency department with a chief complaint of headache from December 1994 through May 1995. Patients with altered mental status or seizures were excluded. Mode of arrival was classified as either by EMS or other (e.g., private vehicle). Patients with a final diagnosis of meningitis, intracranial hemorrhage, or central nervous system tumor were classified as having serious causes, whereas those with headache due to migraine, tension headache, or headache that was otherwise unspecified were classified as nonserious. The use of diagnostic studies, such as lumbar puncture or CT scan, and their results, was recorded. Patients were included in the category of patients having serious intracranial pathology even if the diagnosis was delayed. Statistical analysis was performed using the Yates-corrected chi-square test, and by determining odds ratios (ORs) with 95% confidence intervals. RESULTS: For 967 patients presenting with a chief complaint of headache, 837 charts were included in the analysis. A total of 102 patients arrived by EMS, and 735 arrived by other means. Patients arriving by EMS had a higher rate of serious cause of headache than did those arriving by other means (OR = 18.5, p < 0.0001). EMS patients tended to undergo additional diagnostic testing (OR = 4.4, p < 0.0001), and those tests were more likely to be abnormal than for those arriving by other means (OR = 9.4, p < 0.0001). Males had a somewhat higher rate of serious diagnosis (OR = 2.6, p < 0.05). CONCLUSIONS: In this EMS system, patients with headache who arrive by EMS are more likely to have serious causes. Mode of arrival may be of use to the clinician in assessing risk of serious illness among patients with headache. Whether this observation represents an element of self-triage or a combination of other factors remains to be determined.

EMS systems and managed care integration.

Emergency medical services systems and MCOs must cooperate and educate each other in order to effect delivery of reliable, high-quality emergency health care to the entire community. Shared goals are rapid access, medically appropriate care, and operational efficiency. An integrated approach is necessary in order to maintain the integrity of EMS systems. EMS systems serve as a safety net for patients with perceived emergencies. Changes in form and function should be guided by outcome studies that ensure the continued delivery of quality emergency health care services.