Corrigendum: Correlative Live-Cell and Super-Resolution Imaging to Link Presynaptic Molecular Organisation With Function

[This corrects the article DOI: 10.3389/fnsyn.2022.830583.].

Correlative Live-Cell and Super-Resolution Imaging to Link Presynaptic Molecular Organisation With Function

Information transfer at synapses occurs when vesicles fuse with the plasma membrane to release neurotransmitters, which then bind to receptors at the postsynaptic membrane. The process of neurotransmitter release varies dramatically between different synapses, but little is known about how this heterogeneity emerges. The development of super-resolution microscopy has revealed that synaptic proteins are precisely organised within and between the two parts of the synapse and that this precise spatiotemporal organisation fine-tunes neurotransmission. However, it remains unclear if variability in release probability could be attributed to the nanoscale organisation of one or several proteins of the release machinery. To begin to address this question, we have developed a pipeline for correlative functional and super-resolution microscopy, taking advantage of recent technological advancements enabling multicolour imaging. Here we demonstrate the combination of live imaging of SypHy-RGECO, a unique dual reporter that simultaneously measures presynaptic calcium influx and neurotransmitter release, with post hoc immunolabelling and multicolour single molecule localisation microscopy, to investigate the structure-function relationship at individual presynaptic boutons.

HIV-1 Rev interacts with HERV-K RcREs present in the human genome and promotes export of unspliced HERV-K proviral RNA

BACKGROUND

The HERV-K (HML-2) viruses are the youngest of the human endogenous retroviruses. They are present as several almost complete proviral copies and numerous fragments in the human genome. Many HERV-K proviruses express a regulatory protein Rec, which binds to an element present in HERV-K mRNAs called the RcRE. This interaction is necessary for the nucleo-cytoplasmic export and expression of HERV-K mRNAs that retain introns and plays a role analogous to that of Rev and the RRE in HIV replication. There are over 900 HERV-K RcREs distributed throughout the human genome. Thus, it was of interest to determine if Rev could functionally interact with selected RcRE elements that map either to HERV-K proviruses or human gene regions. This interaction would have the potential to alter the expression of both HERV-K mRNAs and cellular mRNAs during HIV-1 infection.

RESULTS

In this study we employed a combination of RNAseq, bioinformatics and cell-based functional assays. Potential RcREs were identified through a number of bioinformatic approaches. They were then tested for their ability to promote export and translation of a reporter mRNA with a retained intron in conjunction with Rev or Rec. Some of the selected elements functioned well with either Rev, Rec or both, whereas some showed little or no function. Rev function on individual RcREs varied and was also dependent on the Rev sequence. We also performed RNAseq on total and cytoplasmic RNA isolated from SupT1 cells expressing HIV Rev, with or without Tat, or HERV-K Rec. Proviral mRNA from three HERV-K loci (4p16.1b, 22q11.23 and most significantly 3q12.3) accumulated in the cytoplasm in the presence of Rev or Tat and Rev, but not Rec. Consistent with this, the 3' RcRE from 3q12.3 functioned well with HIV-Rev in our reporter assay. In contrast, this RcRE showed little or no function with Rec.

CONCLUSIONS

The HIV Rev protein can functionally interact with many RcREs present in the human genome, depending on the RcRE sequence, as well as the Rev sequence. This leads to export of some of the HERV-K proviral mRNAs and also has the potential to change the expression of non-viral genes.

Nanoscale Structural Plasticity of the Active Zone Matrix Modulates Presynaptic Function

The active zone (AZ) matrix of presynaptic terminals coordinates the recruitment of voltage-gated calcium channels (VGCCs) and synaptic vesicles to orchestrate neurotransmitter release. However, the spatial organization of the AZ and how it controls vesicle fusion remain poorly understood. Here, we employ super-resolution microscopy and ratiometric imaging to visualize the AZ structure on the nanoscale, revealing segregation between the AZ matrix, VGCCs, and putative release sites. Long-term blockade of neuronal activity leads to reversible AZ matrix unclustering and presynaptic actin depolymerization, allowing for enrichment of AZ machinery. Conversely, patterned optogenetic stimulation of postsynaptic neurons retrogradely enhanced AZ clustering. In individual synapses, AZ clustering was inversely correlated with local VGCC recruitment and vesicle cycling. Acute actin depolymerization led to rapid (5 min) nanoscale AZ matrix unclustering. We propose a model whereby neuronal activity modulates presynaptic function in a homeostatic manner by altering the clustering state of the AZ matrix.

An annotated bibliography of verbal behavior articles published outside of The Analysis of Verbal Behavior: 2016

An annotated bibliography is provided that summarizes journal articles on verbal behavior published outside of The Analysis of Verbal Behavior in 2016, the primary journal for scholarship in this area. Thirty-seven such articles were identified and annotated as a resource for practitioners, researchers, and educators.

Distance-dependent gradient in NMDAR-driven spine calcium signals along tapering dendrites

Neurons receive a multitude of synaptic inputs along their dendritic arbor, but how this highly heterogeneous population of synaptic compartments is spatially organized remains unclear. By measuring N-methyl-d-aspartic acid receptor (NMDAR)-driven calcium responses in single spines, we provide a spatial map of synaptic calcium signals along dendritic arbors of hippocampal neurons and relate this to measures of synapse structure. We find that quantal NMDAR calcium signals increase in amplitude as they approach a thinning dendritic tip end. Based on a compartmental model of spine calcium dynamics, we propose that this biased distribution in calcium signals is governed by a gradual, distance-dependent decline in spine size, which we visualized using serial block-face scanning electron microscopy. Our data describe a cell-autonomous feature of principal neurons, where tapering dendrites show an inverse distribution of spine size and NMDAR-driven calcium signals along dendritic trees, with important implications for synaptic plasticity rules and spine function.

A multicentre snapshot study of the incidence of serious procedural complications secondary to central venous catheterisation

Despite the high number of central venous access devices inserted annually, there are limited data on the incidence of the associated procedural complications, many of which carry substantial clinical risk. This point was highlighted in the recently published Association of Anaesthetists of Great Britain and Ireland 'Safe vascular access 2016' guidelines. This trainee-led snapshot study aimed to identify the number of central venous catheter insertions and the incidence of serious complications across multiple hospital sites within a fixed two-week period. Secondary aims were to identify the availability of resources and infrastructure to facilitate safe central venous catheter insertion and management of potential complications. Fifteen hospital sites participated, completing an initial resource survey and daily identification of all adult central venous catheter insertions, with subsequent review of any complications detected. A total of 487 central venous catheter insertions were identified, of which 15 (3.1%) were associated with a significant procedural complication. The most common complication was failure of insertion, which occurred in seven (1.4%) cases. Facilities to enable safer central venous catheter insertion and manage complications varied widely between hospitals, with little evidence of standardisation of guidelines or protocols.

Visualizing Presynaptic Calcium Dynamics and Vesicle Fusion with a Single Genetically Encoded Reporter at Individual Synapses

Synaptic transmission depends on the influx of calcium into the presynaptic compartment, which drives neurotransmitter release. Genetically encoded reporters are widely used tools to understand these processes, particularly pHluorin-based reporters that report vesicle exocytosis and endocytosis through pH dependent changes in fluorescence, and genetically encoded calcium indicators (GECIs) that exhibit changes in fluorescence upon binding to calcium. The recent expansion of the color palette of available indicators has made it possible to image multiple probes simultaneously within a cell. We have constructed a single molecule reporter capable of concurrent imaging of both presynaptic calcium influx and exocytosis, by fusion of sypHy, the vesicle associated protein synaptophysin containing a GFP-based pHluorin sensor, with the red-shifted GECI R-GECO1. Due to the fixed stoichiometry of the two probes, the ratio of the two responses can also be measured, providing an all optical correlate of the calcium dependence of release. Here, we have characterized stimulus-evoked sypHy-RGECO responses of hippocampal synapses in vitro, exploring the effects of different stimulus strengths and frequencies as well as variations in external calcium concentrations. By combining live sypHy-RGECO imaging with post hoc fixation and immunofluorescence, we have also investigated correlations between structural and functional properties of synapses.

Engineering FKBP-Based Destabilizing Domains to Build Sophisticated Protein Regulation Systems

Targeting protein stability with small molecules has emerged as an effective tool to control protein abundance in a fast, scalable and reversible manner. The technique involves tagging a protein of interest (POI) with a destabilizing domain (DD) specifically controlled by a small molecule. The successful construction of such fusion proteins may, however, be limited by functional interference of the DD epitope with electrostatic interactions required for full biological function of proteins. Another drawback of this approach is the remaining endogenous protein. Here, we combined the Cre-LoxP system with an advanced DD and generated a protein regulation system in which the loss of an endogenous protein, in our case the tumor suppressor PTEN, can be coupled directly with a conditionally fine-tunable DD-PTEN. This new system will consolidate and extend the use of DD-technology to control protein function precisely in living cells and animal models.

Groundwater protection and unconventional gas extraction: the critical need for field-based hydrogeological research

Unconventional natural gas extraction from tight sandstones, shales, and some coal-beds is typically accomplished by horizontal drilling and hydraulic fracturing that is necessary for economic development of these new hydrocarbon resources. Concerns have been raised regarding the potential for contamination of shallow groundwater by stray gases, formation waters, and fracturing chemicals associated with unconventional gas exploration. A lack of sound scientific hydrogeological field observations and a scarcity of published peer-reviewed articles on the effects of both conventional and unconventional oil and gas activities on shallow groundwater make it difficult to address these issues. Here, we discuss several case studies related to both conventional and unconventional oil and gas activities illustrating how under some circumstances stray or fugitive gas from deep gas-rich formations has migrated from the subsurface into shallow aquifers and how it has affected groundwater quality. Examples include impacts of uncemented well annuli in areas of historic drilling operations, effects related to poor cement bonding in both new and old hydrocarbon wells, and ineffective cementing practices. We also summarize studies describing how structural features influence the role of natural and induced fractures as contaminant fluid migration pathways. On the basis of these studies, we identify two areas where field-focused research is urgently needed to fill current science gaps related to unconventional gas extraction: (1) baseline geochemical mapping (with time series sampling from a sufficient network of groundwater monitoring wells) and (2) field testing of potential mechanisms and pathways by which hydrocarbon gases, reservoir fluids, and fracturing chemicals might potentially invade and contaminate useable groundwater.

Effect of food and temperature on emergence from diapause in the tarnished plant bug (Hemiptera: Miridae)

Tarnished plant bugs, Lygus lineolaris (Palisot de Beauvois), overwinter as diapausing adults in North America. Overwintering adults were collected near Stoneville, MS from blooming henbit, Lamium amplexicaule L., and from plant debris during December and January and dissected to determine their reproductive status. Averaged over four winters, male and female tarnished plant bugs collected from henbit terminated diapause at a significantly higher rate than males and females from plant debris during each week of December and the first week of January. Both sexes in each habitat were nearly all reproductive by the end of January. Adults overwintering in plant debris terminated diapause during January in the absence of a food stimulus in all 5 yr studied. This emergence was thought to be controlled by an internal clock. Laboratory and field studies showed that emergence from diapause could be influenced by food, sex, and temperature. Adults overwintering on a suitable food source, blooming henbit, terminated diapause during December in the 4 yr studied, and males terminated diapause more rapidly than females. Food quality was important in emergence from diapause, and females on blooming henbit terminated diapause at a significantly higher rate than females on nonblooming mustard, Brassica juncea (L.) Cosson. Laboratory tests showed that diapausing adults reared in the laboratory and held at a diapause-maintaining photoperiod of 10:14 (L:D) h could be terminated from diapause by using food and temperature stimuli. The lower thermal threshold for development to reproductive adults was found to be near 10°C. The ability of diapausing adults to respond to food and temperature stimuli in December can enable tarnished plant bugs to take advantage of warm winters and winter hosts to produce a new generation earlier.

Utilization of early soybeans for food and reproduction by the tarnished plant bug (Hemiptera: Miridae) in the delta of Mississippi

Commercially produced maturity group (MG) IV soybeans, Glycine max L., were sampled during bloom for tarnished plant bugs, Lygus lineolaris (Palisot de Beauvois), during May and June 1999 (3 fields) and 2001 (18 fields). The adults and nymphs were found primarily in single population peaks in both years, indicating a single new generation was produced during each year. The peak mean numbers of nymphs were 0.61 and 0.84 per drop cloth sample in 1999 and 2001, respectively. Adults peaked at 3.96 (1999) and 3.76 (2001) per sweep net sample (25 sweeps). Tests using laboratory-reared and field-collected tarnished plant bugs resulted in very poor survival of nymphs on 16 different soybean varieties (MG III, one; IV, four; V, nine; VI, two). A large cage (0.06 ha) field test found that the number of nymphs produced on eight soybean varieties after mated adults were released into the cages was lower than could be expected on a suitable host. These results indicated that soybean was a marginal host for tarnished plant bugs. However, the numbers of adults and nymphs found in the commercially produced fields sampled in the study may have been high enough to cause feeding damage to the flowering soybeans. The nature of the damage and its possible economic importance were not determined. Reproduction of tarnished plant bugs in the commercially produced early soybean fields showed that the early soybeans provided tarnished plant bugs with a very abundant host at a time when only wild hosts were previously available.

Cross-resistance responses of CrylAc-selected Heliothis virescens (Lepidoptera: Noctuidae) to the Bacillus thuringiensis protein vip3A

One susceptible and three Cry1Ac-resistant strains of tobacco budworm, Heliothis virescens (F.) (Lepidoptera: Noctuidae), were used in laboratory studies to determine the level of cross-resistance between the Bacillus thuringiensis (Berliner) toxins Cry1Ac and Vip3A by using concentration-mortality and leaf tissue experiments. Concentration-mortality data demonstrated that the three Cry1Ac-resistant H. virescens strains, YHD2, KCBhyb, and CxC, were at least 215- to 316-fold resistant to Cry1Ac compared with the susceptible strain, YDK. Results from Vip3A concentration-mortality tests indicated that mortality was similar among all four H. virescens strains. Relative larval growth on Cry1Ac reflected concentration-mortality test results, because YHD2 larval growth was mostly unaffected by the Cry1Ac concentrations tested. Growth ratios for KCBhyb and CXC indicated that they had a more moderate level of resistance to Cry1Ac than did YHD2. Relative larval growth on Vip3A was highly variable at lower concentrations, but it was more consistent on concentrations of Vip3A above 25 microg/ml. Differences in larval growth among strains on Vip3A were not as pronounced as seen in Cry1Ac experiments. Mortality and larval growth also was assessed in leaf tissue bioassays in which YDK, CxC, and KCBhyb neonates were placed onto leaf disks from non-Bt and Bt cotton, Gossypium hirsutum L., for 5 d. Three Bt lines were used in an initial bioassay and consisted of two Vip3A-containing lines, COT203 and COT102, and a Cry1Ac-producing line. Mortality of KCBhyb and CXC was lower than that of YDK larvae in the presence of leaf tissue from the Cry1Ac-producing line. Additionally, increased larval growth and leaf tissue consumption on Cry1Ac-containing leaf disks was observed for KCBhyb and CXC. Mortality and larval weights were similar among strains when larvae were fed leaf tissue of either non-Bt, COT203, or COT102. A subsequent leaf tissue bioassay was conducted that evaluated four cotton lines: non-Bt, Cry1Ab-expressing, Vip3A-expressing, and pyramided-toxin plants that produced both Cry1Ab and Vip3A. Mortality levels were similar among strains when fed non-Bt, Vip3A-expressing, or pyramided-toxin leaf tissues. Mortality was higher for YDK than for KCBhyb or CXC on Cry1Ab-expressing leaf tissues. No differences in larval weights were observed among strains for any genotype tested. Results of these experiments demonstrate that cross-resistance is nonexistent between CrylAc and Vip3A in H. virescens. Thus, the introduction of Vip3A-producing lines could delay Cry1Ac-resistance evolution in H. virescens, if these lines gain a significant share of the market.

Genetic variation for resistance to Bacillus thuringiensis toxins in Helicoverpa zea (Lepidoptera: Noctuidae) in eastern North Carolina

To evaluate resistance to Bacillus thuringiensis Berliner (Bt) toxins, adult female bollworms, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), were collected from four light trap locations in two eastern North Carolina counties from August to October during 2001 and 2002. Females were allowed to oviposit, and upon hatching, 24 neonates from each female (F1 lines) were screened for survival and growth rate on each of three diets: non-Bt diet, diet containing 5.0 microg/ml Cry1Ac toxin, or diet containing 5.0 microg/ml Cry2Ab toxin. These screens were designed to identify nonrecessive Bt resistance alleles present in field populations of bollworm. Of 561 and 691 families screened with both Cry1Ac- and Cry2Ab-containing diets in 2001 and 2002, respectively, no F1 lines were identified that seemed to carry a gene conferring substantial resistance to either Cry1Ac or Cry2Ab. Adults from F1 lines with growth scores in the highest (R) and lowest (S) quartiles were mated in four combinations, RxR, SxR, RxS, and SxS. Differences in growth rates of larvae from these crosses demonstrated that there is substantial quantitative genetic variation in eastern North Carolina populations for resistance to both Cry1Ac and Cry2Ab toxins. These findings, in addition to results suggesting partially dominant inheritance of resistance to Cry1Ac and Cry2Ab, are critically important for determining appropriate resistance management strategies that impact the sustainability of transgenic cotton, Gossypium hirsutum (L.).

Comparative production of Helicoverpa zea (Lepidoptera: Noctuidae) from transgenic cotton expressing either one or two Bacillus thuringiensis proteins with and without insecticide oversprays

Transgenic cotton, Gossypium hirsutum (L.), expressing either one or two Bacillus thuringiensis ssp. kurstaki Berliner (Bt) proteins was compared with the conventional sister line in field experiments with regard to production of bollworm, Helicoverpa zea (Boddie), and bolls damaged by bollworm. The relative numbers of bollworms that developed on Bollgard (Monsanto Co., St. Louis, MO), Bollgard II (Monsanto Co.), and conventional cotton were estimated under nontreated conditions in 2000 and both insecticide-treated and nontreated conditions in 2001-2002 in North Carolina tests. Averaged across seven field studies under nontreated conditions, Bollgard cotton generated statistically similar numbers of large (L4-L5) bollworm larvae compared with the conventional variety; however, Bollgard cotton produced significantly fewer damaged bolls and bollworm adults than the conventional variety. Production of large larvae, damaged bolls, and adults was decreased dramatically by Bollgard II cotton as compared with Bollgard and conventional varieties. When comparing insecticide-treated and nontreated cotton genotypes, both Bt cotton sustained less boll damage than the conventional variety averaged across insecticide regimes; furthermore, Bollgard II cotton had fewer damaged bolls than the Bollgard variety. When averaged across cotton genotypes, pyrethroid oversprays reduced the numbers of damaged bolls compared with the nontreated cotton. Insecticide-treated Bollgard cotton, along with insecticide-treated and nontreated Bollgard II cotton reduced production of bollworm larvae, pupae, and adults. However, the addition of pyrethroid oversprays to Bollgard II cotton seemed to be the best resistance management strategy available for bollworm because no bollworms were capable of completing development under these conditions.

Cardiac arrest in private locations: different strategies are needed to improve outcome

BACKGROUND

A tremendous amount of public resources are focused on improving cardiac arrest (OHCA) survival in public places, yet most OHCAs occur in private residences.

METHODS AND RESULTS

A prospective, observational study of patients transported to seven urban and suburban hospitals and the individuals who called 911 at the time of a cardiac arrest (bystander) was performed. Bystanders (N=543) were interviewed via telephone beginning 2 weeks after the incident to obtain data regarding patient and bystander demographics, including cardiopulmonary resuscitation (CPR) training. Of all arrests 80.2% were in homes. Patients who arrested in public places were significantly younger (63.2 vs. 67.2, P<0.02), more often had an initial rhythm of VF (63.0 vs. 37.7%, P<0.001), were seen or heard to have collapsed by a bystander (74.8 vs. 48.1%, P<0.001), received bystander CPR (60.2 vs. 28.6%, P<0.001), and survived to DC (17.5 vs. 5.5%, P<0.001). Patients who arrested at home were older and had an older bystander (55.4 vs. 41.3, P<0.001). The bystander was less likely to be CPR trained (65.0 vs. 47.4%, P<0.001), less likely to be trained within the last 5 years (49.2 vs. 17.9, P<0.001), and less likely to perform CPR if trained (64.2 vs. 30.0%, P<0.001). Collapse to shock intervals for public versus home VF patients were not different.

CONCLUSIONS

Many important characteristics of cardiac arrest patients and the bystander differ in public versus private locations. Fundamentally different strategies are needed to improve survival from these events.

Performance assessment of NAPL remediation in heterogeneous alluvium

Over the last few years, more than 40 partitioning interwell tracer tests (PITTs) have been conducted at many different sites to measure nonaqueous phase liquid (NAPL) saturations in the subsurface. While the main goal of these PITTs was to estimate the NAPL volume in the subsurface, some were specifically conducted to assess the performance of remedial actions involving NAPL removal. In this paper, we present a quantitative approach to assess the performance of remedial actions to recover NAPL that can be used to assess any NAPL removal technology. It combines the use of PITTs (to estimate the NAPL volume in the swept pore volume between injection and extraction wells of a test area) with the use of several cores to determine the vertical NAPL distribution in the subsurface. We illustrate the effectiveness of such an approach by assessing the performance of a surfactant/foam flood conducted at Hill Air Force Base, UT, to remove a TCE-rich NAPL from alluvium with permeability contrasts as high as one order of magnitude. In addition, we compare the NAPL volumes determined by the PITTs with volumes estimated through geostatistical interpolation of aquifer sediment core data collected with a vertical frequency of 5-10 cm and a lateral borehole spacing of 0.15 m. We demonstrate the use of several innovations including the explicit estimation of not only the errors associated with NAPL volumes and saturations derived from PITTs but also the heterogeneity of the aquifer sediments based upon permeability estimates. Most importantly, we demonstrate the reliability of the

A randomized trial of the effects of early cardiac serum marker availability on reperfusion therapy in patients with acute myocardial infarction: the serial markers, acute myocardial infarction and rapid treatment trial (SMARTT)

OBJECTIVES

The purpose of this study was to assess whether the immediate availability of serum markers would increase the appropriate use of thrombolytic therapy.

BACKGROUND

Serum markers such as myoglobin and creatine kinase, MB fraction (CK-MB) are effective in detecting acute myocardial infarction (AMI) in the emergency setting. Appropriate candidates for thrombolytic therapy are not always identified in the emergency department (ED), as 20% to 30% of eligible patients go untreated, representing 10% to 15% of all patients with AMI. Patients presenting with chest pain consistent with acute coronary syndrome were evaluated in the EDs of 12 hospitals throughout North America.

METHODS

In this randomized, controlled clinical trial, physicians received either the immediate myoglobin/CK-MB results at 0 and 1 h after enrollment (stat) or conventional reporting of myoglobin/CK-MB 3 h or more after hospital admission (control). The primary end point was the comparison of the proportion of patients within the stat group versus control group who received appropriate thrombolytic therapy. Secondary end points included the emergent use of any reperfusion treatment in both groups, initial hospital disposition of patients (coronary care unit, monitor or nonmonitor beds) and the proportion of patients appropriately discharged from the ED.

RESULTS

Of 6,352 patients enrolled, 814 (12.8%) were diagnosed as having AMI. For patients having AMI, there were no statistically significant differences in the proportion of patients treated with thrombolytic therapy between the stat and control groups (15.1% vs. 17.1%, p = 0.45). When only patients with ST segment elevation on their initial electrocardiogram were compared, there were still no significant differences between the groups. Also, there was no difference in the hospital placement of patients in critical care and non- critical care beds. The availability of early markers was associated with more hospital admissions as compared to the control group, as the number of patients discharged from the ED was decreased in the stat versus control groups (28.4% vs. 31.5%, p = 0.023).

CONCLUSIONS

The availability of 0- and 1-h myoglobin and CK-MB results after ED evaluation had no effect on the use of thrombolytic therapy for patients presenting with AMI, and it slightly increased the number of patients admitted to the hospital who had no evidence of acute myocardial necrosis.

Prospective evaluation of two-dimensional transthoracic echocardiography in emergency department patients with suspected pulmonary embolism

OBJECTIVE

To prospectively examine the diagnostic accuracy of two-dimensional transthoracic echocardiography (2-D echo) in emergency department (ED) patients being evaluated for acute pulmonary embolism (PE).

METHODS

This was a 14-month prospective observational trial of a convenience sample of ED patients undergoing evaluation for suspected PE at a suburban teaching hospital. The 2-D echo was defined as positive if any two of the following were noted: right ventricular dilation, abnormal septal motion, loss of right ventricular contractility, elevated pulmonary artery or right ventricular pressures, moderate to severe tricuspid regurgitation, or visualization of a clot seen in the right ventricle or pulmonary artery. The patient was considered to have a PE if one of the following was positive: a pulmonary angiogram, contrast helical computed tomography, a magnetic resonance angiogram, a high-probability ventilation/perfusion (V/Q) scan without contradictory evidence, or an intermediate-probability V/Q scan with ultrasonic evidence of deep venous thrombosis.

RESULTS

Of 225 cases identified, 39 met the defined criteria for PE (17%). A 2-D echo was performed on 124 patients (55%), of whom 27 (22%) had PE. In 20 patients the 2-D echo had at least two indicators of right ventricular strain; however, only 11 of these patients had confirmed pulmonary embolus. The 2-D echo had a sensitivity of 0.41 (95% CI = 0.32 to 0.49) and a specificity of 0.91 (95% CI = 0.86 to 0.96). The likelihood ratio positive was a moderately strong 4.4, with a weak likelihood ratio negative of 0.6.

CONCLUSIONS

Bedside 2-D echo is not a sensitive test for the diagnosis of PE in ED patients. Positive findings moderately increase the suspicion for PE but are not diagnostic.

Does advanced age matter in outcomes after out-of-hospital cardiac arrest in community-dwelling adults?

OBJECTIVE

To assess whether advanced age is an independent predictor of survival to hospital discharge in community-dwelling adult patients who sustained an out-of-hospital cardiac arrest in a suburban county.

METHODS

A prospective cohort study was conducted in a suburban county emergency medical services system of community-dwelling adults who had an arrest from a presumed cardiac cause and who received out-of-hospital resuscitative efforts from July 1989 to December 1993. The cohorts were defined by grouping ages by decade: 19-39, 40-49, 50-59, 60-69, 70-79, and 80 or more. The variables measured included age, gender, witnessed arrest, response intervals, location of arrest, documented bystander cardiopulmonary resuscitation, and initial rhythms. The primary outcome was survival to hospital discharge. Results are reported using analysis of variance, chi square, and adjusted odds ratios from a logistic regression model. Age group 50-59 served as the reference group for the regression model.

RESULTS

Of the 2,608 total presumed cardiac arrests, the overall survival rate to hospital discharge was 7.25%. Patients in age groups 40-49 and 50-59 experienced the best rate of successful resuscitation (10%). Each subsequent decade had a steady decline in successful outcome: 8.1% for ages 60-69; 7.1% for ages 70-79; and 3.3% for age 80+. In a post-hoc analysis, further separation of the older age group revealed a successful outcome in 3.9% of patients ages 80-89 and 1% in patients 90 and older. Patients aged 80 years or more were more likely to arrest at home, were more likely to have an initial bradyasystolic rhythm, yet had a similar rate of resuscitation to hospital admission. In the regression model, age 80 or older was associated with a significantly worse survival to hospital discharge (OR = 0.4, 95% CI = 0.20 to 0.82).

CONCLUSIONS

There was a twofold decrease in survival following out-of-hospital cardiac arrest to discharge in patients aged 80 or more when compared with the reference group in this suburban county setting. However, resuscitation for community-dwelling elders aged 65-89 is not futile. These data support that out-of-hospital resuscitation of elders up to age 90 years is not associated with a universal dismal outcome.

Effects of acute pain reduction methods on the chronic inflammatory lesions and behaviour of lambs castrated and tail docked with rubber rings at less than two days of age

Lesions were produced by castration and tail docking of two-day-old Dorset-cross lambs with elastrator rings with (RRla) and without (RR) local anaesthetic or after destruction of the innervation by crushing close to the ring (Brr). The lesions were monitored twice weekly for six weeks and the behaviour of handled controls (H), RR and RRla lambs was recorded for two 3 h periods 10, 20, 31 and 41 days after treatment. There was no significant effect of castration and tail docking, with or without pain reduction methods, on daily liveweight gain. In the Brr lambs, the dead tails were cast 10 days earlier than from RR and RRla lambs. The time taken for the scrotal lesion to reach maximum severity was halved in Brr and RRla lambs, although the maximum severity of the lesion was unaffected by the methods of pain reduction. During the four 6 h behavioural observation periods, RR lambs showed a significant increase in the mean (+/- sd) frequency of foot stamping (RR13 +/- 13; H2 +/- 2.5), tail wagging (61 +/- 26; 15 +/- 6), head turning to the scrotum and inside hind-leg (12 +/- 10; 1 +/- 1). Less abnormal behaviour was found after RRla than after RR treatment. This unexpected finding may be evidence of long-lasting increases in pain sensitivity after an episode of intense acute pain in young animals.

Utility of lower extremity venous ultrasound scanning in the diagnosis and exclusion of pulmonary embolism in outpatients

STUDY OBJECTIVE

Emergency physicians frequently rely on normal findings from a lower extremity venous ultrasound examination as a method to decrease the probability of pulmonary embolism (PE) in outpatients with a nondiagnostic ventilation-perfusion lung scan (V/Q scan). The objective of this study was to evaluate the diagnostic utility of bilateral lower extremity venous ultrasound scanning in the diagnosis of PE in emergency department patients with a low-, moderate-, or indeterminate-probability (nondiagnostic) V/Q scan.

METHODS

This prospective, 2-center, descriptive study was conducted at the EDs of 2 large teaching hospitals. From an initial cohort of 570 nonreferred outpatients, a convenience sample of 156 patients who had both a nondiagnostic V/Q scan and a lower extremity venous ultrasound scan performed was selected as the study population. The sensitivity and specificity for a single lower extremity venous ultrasound scan and the posttest probability of PE were determined for the study population.

RESULTS

In the study population, the best-case sensitivity of the lower extremity venous ultrasound scan for PE was 54% (95% confidence interval [CI] 37% to 71%) and the specificity was 98% (95% CI 94% to 100%). The likelihood ratio of a positive test result was 27. The likelihood ratio of a negative test result was 0.49, yielding a lowest possible posttest probability of PE of 12% (95% CI 6% to 17%).

CONCLUSION

This study demonstrates that the combination of a nondiagnostic (low, moderate, or indeterminate) V/Q scan plus a single negative result from lower extremity venous ultrasound examination, even in a best-case scenario, does not exclude the diagnosis of PE.

Behavioural and physiological responses of sheep to 16 h transport and a novel environment post-transport

The effect of a novel lairage environment on the ability of sheep to recover from 16 h of transport was investigated. Sheep were transported from grass paddocks to either novel outside paddocks or inside pens, and housed groups were transported to either familiar or novel inside pens. During transport, sheep from outside paddocks lay down less than those from inside pens. In sheep transported to inside pens, those from outside paddocks spent more time lying and spent less time eating; hay and water intakes during the first 12 h post-transport were lower than those previously kept inside. There was no obvious effect of a novel environment post-transport on blood biochemistry, suggesting that the lower post-transport feed and water intakes in a novel environment did not have a significant effect on the ability of the sheep to recover from the feed and water deprivation associated with transport.

Impact of lay responder actions on out-of-hospital cardiac arrest outcome

INTRODUCTION

Little peer-reviewed literature exists regarding the actions of the person who recognized and called 911 at the time of an out-of-hospital cardiac arrest (OHCA).

OBJECTIVES

To describe the characteristics of persons who recognized OHCAs and to assess the impact of their actions on survival.

METHODS

Subjects were a convenience sample of individuals who called 911 after a case of home OHCA in which the victim was transported to one of two suburban community teaching hospitals. A retrospective mail survey was conducted asking demographics, including age, race, educational level, prior first aid training, and actions upon recognition of OHCA, including phone calls made and caller estimate from collapse to 911 call. Callers whose initial action was calling 911 were compared with those who made other calls first. Outcomes (discharged alive, DC) were obtained from hospital records. Fisher's exact test and chi-square tests were used for analysis.

RESULTS

Of 378 cases, 173 (45.8%) responded to the mail survey. The lay responders (LRs) who called 911 were younger than the victims (59.9 vs 68.0, p < 0.001) and were most commonly spouses (65.3%) or adult children (22.0%) of the patient. Most (84.7%) called 911 first at the time of recognition of arrest. A first call to 911 tended to predict DC (11.0% vs 0.0%, p = 0.13). When a phone call other than 911 was made first, there were no survivors (0/23). An estimated delay to 911 call of >4 minutes was not associated with an adverse outcome (10.5% vs 6.9%, p = 0.49). There was no difference in demographic variables between immediate and delayed 911 callers.

CONCLUSION

Lay responder demographics are similar to those of patients. In this study, an LR call to 911 first appears to be associated with improved OHCA survival. The LR estimates of delay to 911 call were not associated with increased mortality. The authors identified no patient or witness characteristics that were associated with a delay to calling 911 first.

Use of two-dimensional echocardiography for the diagnosis of pulmonary embolus

We investigated the diagnostic utility of transthoracic echocardiogram (2-D ECHO) in identifying acute right heart strain in patients with suspected pulmonary embolus (PE) undergoing a pulmonary angiogram during their hospitalization. A retrospective case control study was conducted over a 3-year period at a tertiary, community teaching hospital. Patients were eligible if they had a pulmonary angiogram and a transthoracic echocardiogram. Cases were defined as an angiogram positive for PE and controls were defined as an angiogram negative for PE. We excluded cases in which the time interval between 2-D ECHO and angiogram was greater than 2 days. The 2-D ECHO was considered positive for right heart strain if two of the following were present: enlarged right ventricle, moderate or severe tricuspid regurgitation, increased right ventricular pressures, or paradoxical septal wall motion. We were able to identify 71 patients, of whom 24 met our criteria for PE. Of these, 13 had an echocardiogram consistent with our definition of acute right heart strain, for a sensitivity of 0.54. Forty-six of the 47 patients without PE did not have findings of acute right heart strain. The echocardiogram was positive in 14 patients, for a positive predictive value of 0.93. In seven patients with systolic blood pressures of less than 100 mmHg, five had a PE, all of whom met our criteria for acute right heart strain. We conclude that 2-D ECHOs show promise in identifying PE and hemodynamic compromise as a result of PE, and that further studies are warranted.

Who gets bystander cardiopulmonary resuscitation in a witnessed arrest?

OBJECTIVE

To identify characteristics associated with provision of bystander CPR in witnessed out-of-hospital cardiac arrest cases.

METHODS

An observational, prospective, cohort study was performed using cardiac arrest cases as identified by emergency medical services (EMS) agencies in Oakland County. MI, from July 1, 1989, to December 31, 1993. All patients who sustained a witnessed arrest prior to arrival of EMS personnel were reviewed.

RESULTS

Of the 927 patients meeting entry criteria, the 229 patients receiving bystander CPR were younger: 60.9 +/- 14.7 vs 67.9 +/- 14.7 years (p < 0.01). Most (76.6%) cardiac arrests occurred in the home. In a multivariate logistic model, only the location of arrest outside the home was a significant predictor of receiving bystander CPR [odds ratio (OR) 3.8; 99% CI 2.5, 5.9]. Arrests outside the home were associated with significantly improved outcome, with 18.2% of out-of-home and 8.2% of in-home victims discharged from the hospital alive (OR 2.5; 99% CI 1.4, 4.4).

CONCLUSION

Patients who have had witnessed cardiac arrests outside the home are nearly 4 times more likely to receive bystander CPR, and are twice as likely to survive. This observation emphasizes the need for CPR training of family members in the authors' locale. This phenomenon may also represent a significant confounder in studies of out-of-hospital cardiac arrest and resuscitation.

Production of virus-specific antisera using synthetic peptides corresponding to sequences in the yellow fever E protein: brief report

Synthetic peptides have gained widespread acceptance for use in epitope mapping and as immunogens for monoclonal antibody and polyclonal serum production. Putative antigenic peptides homologous to regions in the primary sequence of the envelope protein (E) of yellow fever virus (YF17D) were synthesized and evaluated for their ability to produce polyclonal antisera specific for the parent protein and for their reactivity with a panel of E-specific mAb. Antipeptide sera were reacted with native virus in ELISA, Western blot, neutralization, hemagglutination-inhibition, and immunofluorescence tests. Reactive sera were in most cases specific for the original peptide. However, despite the diversity of peptide selection processes, we were unable to identify any antipeptide serum that reacted specifically with authentic YF E protein.

Effect of a patient's sex on the timing of thrombolytic therapy

STUDY OBJECTIVE

We sought to determine whether a patient's sex independently influences the interval from emergency department arrival to the initiation of thrombolytic therapy in acute myocardial infarction (AMI).

METHODS

We conducted a retrospective cohort study in two suburban EDs, one at a 929-bed tertiary care teaching hospital and the other at a 189-bed community hospital. Only patients found to be having an ST-segment-elevated AMI on their first ECG who were treated with a thrombolytic agent in the ED were eligible. We excluded patients who arrived at the ED after cardiac arrest or with a known AMI. We used as the main outcome measure the interval from ED arrival to initiation of thrombolytic therapy. Secondary outcome variables included time elapsed before ECG, interval between ECG and treatment, and 1-year mortality.

RESULTS

Entry criteria were satisfied by 328 patients. The 88 women experienced a mean 23-minute delay to treatment initiation compared with men (P < .01). This observation is not accounted for by age, race, time of day, medical history, sex of the physician, type of thrombolytic agent, hospital, or triage category. The longest delays were found in women treated by female physicians, although female physicians also waited longer than male physicians to administer thrombolytic therapy to men. The mean time elapsed before the first ECG was also 6 minutes longer for women (P < .01) Women had an increased 1-year mortality rate that was fully explained by their advanced age at the time of AMI.

CONCLUSION

We infer that a patient's sex may play a significant role in the observed delay in treatment for women. Our data, coupled with previously published work, strongly suggest a systematic negative effect for women in their interaction with the health care system during AMI. We suggest that variables other than systems issues affect the time elapsed before thrombolytic therapy.

Clinical decision rules discriminate between fractures and nonfractures in acute isolated knee trauma

STUDY OBJECTIVE

To develop criteria that optimize clinical decisionmaking in the use of radiography after isolated knee trauma in adults.

DESIGN

A prospective survey of emergency department patients over a 7-month period. Standardized data forms were completed by emergency physicians, residents, and certified physician assistants.

SETTING

A large suburban community teaching hospital.

PARTICIPANTS

Two hundred forty-two patients older than 17 years with isolated knee injuries sustained less than 24 hours previously.

RESULTS

We constructed a clinical decision model, calculating sensitivity, specificity, and odds ratios. Twenty-eight patients (11.6%) had fractures, with the patella the most commonly fractured osseous structure. Patients able to walk without limping had not experienced a fracture, nor had patients with twist injuries without effusion. Sensitivity of this model for detecting fracture was 1.0 (99% confidence interval, .97 to 1.0), and specificity was .337 (99% confidence interval, .26 to .42).

CONCLUSION

Clinical decision rules are effective in detecting knee fractures with 100% sensitivity and with sufficient specificity to eliminate 29% of knee radiographs in the ED. These findings require prospective validation.

Natural cytokine antagonists and endogenous antiendotoxin core antibodies in sepsis syndrome. The Sepsis Intervention Group

OBJECTIVE

To assess the value of measuring circulating concentrations of mediators (endotoxin, tumor necrosis factor-alpha [TNF-alpha], interleukin-1 beta [IL-1 beta], and interleukin-6[IL-6]) and their endogenous antagonists (antiendotoxin core antibody [EndoCAb], interleukin-1 receptor antagonist [IL-1ra], and soluble TNF receptors [sTNF-R]) in predicting mortality and organ failure in sepsis syndrome.

DESIGN

Cohort study with a follow-up period of 30 days.

SETTING

Intensive therapy units of five tertiary referral centers in Scotland.

SUBJECTS

A total of 146 intensive therapy unit patients with sepsis syndrome underwent repeated sampling during a 10-day period following admission to an intensive therapy unit.

MAIN OUTCOME MEASURES

Circulating concentrations of mediators and antagonists were compared in survivors and nonsurvivors.

RESULTS

Median Acute Physiology and Chronic Health Evaluation II score was 23 (range, 8 to 40). Mortality at 30 days was 49%. On entry to the study, circulating endotoxin was detected in 66% of patients, TNF-alpha in 14%, and IL-1 beta in 29%. Levels did not predict mortality or organ failure. Patients with IL-6 concentrations in excess of 3000 pg/mL had an increased mortality rate (64% vs 40%, P = .02). The incidence of IgG EndoCAb depletion on entry to the study was 26% in nonsurvivors and 10% in survivors (P = .02). Initial concentrations of both type I and type II sTNF-R were significantly higher in nonsurvivors (P < .01). Initial circulating IL-1ra concentrations were not of value in predicting mortality. Cytokine antagonists were present in concentrations 30- to 100,000-fold greater than their corresponding cytokine.

CONCLUSION

The observed high circulating levels of the cytokine antagonists IL-1ra and sTNF-R and the relatively small proportion of patients developing EndoCAb depletion may contribute to the limitations of therapies that aim to augment natural defenses against endotoxin or the proinflammatory cytokines.

Sensitivity of the Ottawa rules

STUDY OBJECTIVE

To validate criteria predicting ankle and mid-foot fractures with 100% sensitivity.

DESIGN

Prospective validation study

SETTING

A 929-bed community teaching hospital with an annual census of 76,488 ED visits.

PARTICIPANTS

Convenience sample of patients older than 18 years with acute ankle or midfoot injury.

INTERVENTIONS

Radiography was performed in each patient received after pertinent history and physical examination findings were recorded.

RESULTS

Five hundred seventy radiographs were obtained in 484 patients. Four hundred twenty-one were of the ankle, and 149 were of the foot. There were 93 ankle fractures and 29 midfoot fractures, giving a fracture yield of 22.1% for ankle films and 19.5% for foot films. Decision rules had sensitivity of 94.6% and specificity of 15.5% for ankle fractures and sensitivity of 93.1% and specificity of 11.5% for midfoot fractures. Prospective criteria failed to predict fracture in five of the ankle group and two of the midfoot group. Physicians predicting fracture solely on the basis of clinical suspicion had a sensitivity of 69% in ankle injuries and 76% in midfoot injuries.

CONCLUSION

We were unable to validate with 100% sensitivity the Ottawa rules predicting ankle and midfoot fractures. However, the Ottawa rules were more sensitive than clinical suspicion alone.

Bystander vs EMS first-responder CPR: initial rhythm and outcome in witnessed nonmonitored out-of-hospital cardiac arrest

OBJECTIVES

To assess whether outcome and first-monitored rhythm for patients who sustain a witnessed, nonmonitored, out-of-hospital cardiac arrest are associated with on-scene CPR provider group.

METHODS

A retrospective, cohort analysis was conducted in a suburban, heterogeneous EMS system. Patients studied were > or = 19 years of age, had had an arrest of presumed cardiac origin between July 1989 and January 1993, had gone into cardiac arrest prior to ALS arrival, and had received CPR on collapse. First-monitored rhythms and survival rates were compared for two patient groups who on collapse either: 1) had received CPR by nonprofessional bystanders (BCPR) or 2) had received CPR by on-scene EMS system first responders (FRCPR).

RESULTS

Of 217 cardiac arrest victims, 153 (71%) had received BCPR and 64 (29%) had received FRCPR. The BCPR patients were slightly younger (62.4 vs 68.4 years, p = 0.01) and had slightly shorter ALS response intervals (6.4 vs 7.7 minutes, p = 0.02). There was no difference in BLS response time intervals or automatic external defibrillator (AED) use rates. The percentage of patients with a first-monitored rhythm of pulseless ventricular tachycardia/ventricular fibrillation (VT/VF) and the percentage of patients grouped by CPR provider who survived to hospital admission or to hospital discharge were: [see text]

Bystander CPR, ventricular fibrillation, and survival in witnessed, unmonitored out-of-hospital cardiac arrest

STUDY OBJECTIVE

To assess whether bystander CPR (BCPR) on collapse affects initial rhythm and outcome in patients with witnessed, unmonitored out-of-hospital cardiac arrest (OHCA).

DESIGN

Prospective cohort study. Student's t test, the chi 2 test, and logistic regression were used for analysis.

SETTING

Suburban emergency medical service (EMS) system.

PARTICIPANTS

Patients 19 years or older with witnessed OHCA of presumed cardiac origin who experienced cardiac arrest before EMS arrival between July 1989 and July 1993.

RESULTS

Of 722 patients who met the entry criteria, 153 received BCPR. Patients who received BCPR were younger than those who did not: 62.5 +/- 15.4 years versus 66.8 +/- 15.1 years (P < .01). We found no differences in basic or advanced life support response intervals or in frequency of AED use. More patients initially had ventricular fibrillation (VF) in the BCPR group: 80.9% versus 61.4% (P < .01). The interval to definitive care for ventricular tachycardia (VT)/VF was longer for the BCPR group (8.59 +/- 5.3 versus 7.45 +/- 4.7 minutes; P < .05). The percentage of patients discharged alive who were initially in VT/VF was higher in the BCPR group: 18.3% versus 8.4% (P < .001). In a multivariate model, BCPR is a significant predictor for VT/VF and live discharge with adjusted ORs of 2.7 (95% CI, 1.7 to 4.4) and 2.4 (95% CI, 1.5 to 4.0), respectively. For those patients in VT/VF, BCPR predicted live discharge from hospital with an adjusted OR of 2.1 (95% CI, 1.2 to 3.6).

CONCLUSION

Patients who receive BCPR are more often found in VT/VF and have an increased rate of live discharge, with controls for age and response and definitive care intervals. For VT/VF patients, BCPR is associated with an increased rate of live discharge.

Massive splenomegaly in sarcoidosis

We have presented a case of massive splenomegaly. Our patient was initially thought to have lymphoma, but at operation she was found to have sarcoidosis with splenic involvement. At 2250 g, the spleen was one of the largest recorded in the literature on sarcoidosis. Although the spleen is frequently involved in sarcoidosis, a review of 6074 cases showed that the incidence of actual splenomegaly is only 10%. In 628 of these cases the authors described various degrees of splenomegaly, but the incidence of massive splenomegaly was only 3%. We conclude that sarcoidosis must be considered in the differential diagnosis of splenomegaly.

A selective approach to operative cholangiography

The value of operative cholangiography in the detection of common bile duct stones has been documented in a number of studies. This study suggests that operative cholangiography can be-used successfully on a more selective basis when used in conjunction with laboratory and operative criteria. One hundred and fifty patients who underwent routine cholecystectomy were retrospectively evaluated. Seventy-five percent had a normal cholangiogram and normal levels of bilirubin and alkaline phosphatase. The remaining 25% had abnormal cholangiograms as well as abnormal laboratory chemistry values. It was noted that if selective operative cholangiography had been performed only on those patients with indications for common bile duct exploration, no ductal stones would have been omitted. Based on these data, a selective approach to operative cholangiography is advocated.

Hypertension in the emergency department

Hypertensive emergencies are now rare and are recognized by the deleterious effect on end-organs. Prompt, efficacious treatment is critical, and the current drug of choice for most episodes is sodium nitroprusside. Hypertensive urgencies are more common than are emergencies, and are distinguished by diastolic pressures greater than 115 mm Hg without end-organ dysfunction. Although there are many efficacious agents, one excellent choice is nifedipine.

Safety evaluation of nabumetone in United States clinical trials

A total of 1,924 persons (rheumatoid arthritis, 835; osteoarthritis, 1,073; volunteers, 16) received nabumetone in United States clinical trials. Nine hundred eighty-eight patients have received nabumetone treatment for periods of more than one year, and 375 patients have received treatment for longer than two years. Four hundred eighty patients over 65 years of age have received treatment with nabumetone, and 224 of these elderly patients have received treatment for periods of more than one year. The nabumetone dose most commonly used in all double-blind trials was 1,000 mg at night. In long-term, open-label studies, which were usually extensions of the double-blind trials, patients could increase the dose to 2,000 mg per day. Nine hundred nineteen patients received doses of more than 1,000 mg per day. Adverse experience information was collected at each visit, including information for some patients receiving treatment for more than three years. Laboratory data were collected periodically throughout the trials, and the data were assessed for trends over time. The adverse experience pattern observed for nabumetone is similar to that described for clinical trial data for other nonsteroidal anti-inflammatory drugs. However, it is noteworthy that the pattern observed for nabumetone is from clinical trials with approximately 1,000 patients receiving treatment for periods of one year or more. This long-term patient exposure in clinical trials far exceeds long-term clinical trial data for other agents. The types and frequencies of adverse experiences reported by persons treated with nabumetone are relatively constant over the long time period covered by these trials. Also, the adverse experience patterns remained generally constant over time for various populations: all patients, patients 65 or older, female patients, male patients, and patients who received an increased dose of nabumetone. Although some statistically significant trends were detected for some laboratory parameters, there was little indication of significant clinical patterns. Although there were patients with individually important laboratory values, nabumetone was not associated with clinically important adverse laboratory patterns. Overall, the adverse experience data and laboratory data indicate that nabumetone is safe for the treatment of adult patients with rheumatoid arthritis or osteoarthritis.

The incidence of AIDS among blacks and Hispanics

Compared with whites, the acquired immune deficiency syndrome (AIDS) has affected blacks and Hispanics disproportionately. The cumulative incidence (CI) for black men was 2.6, and for Hispanic men 2.5, times the rate for white men. Intravenous (IV) needle use alone does not account for this difference. Not counting IV needle-using cases, the CIs for black and Hispanic men were 1.7 times the CI for white men. Although there were fewer cases in women than men, the white-to-minority disparity was greater for women. The CIs for black and Hispanic women were 12.2 and 8.5 times, respectively, the CI for white women. Prevention programs are urgently needed and should focus on risky behavior (IV needle sharing and receptive anal intercourse), not just risk groups.

Efficacy of benzathine penicillin G in group A streptococcal pharyngitis: reevaluation

The rate of streptococcal eradication after intramuscular administration of benzathine penicillin G in 66 children with acute group A streptococcal pharyngitis was determined and possible reasons for treatment failure explored. Bacteriologic treatment failure, defined as isolation of the same serotype at 3- or 6-weeks follow-up, occurred in eight (12%) patients. The treatment failure rate was 21% in those with immunologically significant infection, versus 8% in those without antibody rises (P greater than 0.1). All group A beta-hemolytic streptococcal (GABS) strains isolated from patients with treatment failure, both before and after benzathine penicillin G therapy, were exquisitely susceptible to penicillin G (minimum inhibitory concentration less than or equal to 0.02 microgram/mL), and none showed evidence of tolerance (minimum bactericidal concentration less than or equal to 0.04 microgram/mL). Thus, we found GABS eradication rates to exceed 10% in children given benzathine penicillin G. The failure rate did not appear to be related to enrichment of the patient population with a high proportion of asymptomatic carriers nor to the presence of penicillin-tolerant GABS.

The value of obtaining renal images following brain scintigraphy with technetium-99m glucoheptonate

The value of adding an extra view of the kidneys immediately following brain imaging with Tc-99m glucoheptonate was investigated in a two-year retrospective study at our institution. Between October 1982 and October 1984, 561 individuals underwent Tc-99m glucoheptonate brain imaging with the added renal view. Twenty-nine of these individuals (5.2%) demonstrated renal abnormalities. The abnormal renal findings were clinically correlated in 24 of these persons. Sixteen (67%) of these 24 individuals were unaware of any renal abnormality. Useful information can be obtained from renal images incidental to brain imaging at no added expense or radiation exposure to the patient, and at a minimal cost in time to the imaging clinic.