Hair-thread tourniquet syndrome .

We have witnessed six cases of the hair-thread tourniquet syndrome, an entity characterized by strangulation of an appendage (toes, fingers, or external genitalia) by hair or hair-like fibers in the pediatric population. All six of our cases were in infants, 12 days to 5 months of age. The offending fibers were hair in three of the four patients with toe injuries and synthetic fibers from mittens in the finger cases. All six patients were treated by immediate removal of the constricting fibers, and, in spite of the worrisome appearance of the tissue distal to the constriction, all six eventually healed without significant tissue loss. A review of the literature indicated 60 similar cases of this type reported, 24 involving toes, 14 involving fingers, and 22 involving genitals. The majority of the toe and external genitalia cases were caused by hair, whereas the majority of finger strangulations were caused by thread from mittens. At greatest risk for strangulation are the middle finger and third toe, followed by the index finger and second toe. Patients with finger or penile involvement were more likely to suffer significant complications from the injuries than those patients with toe involvement. Based on our own experience and that described in the literature, we recommend prompt removal of the offending fiber, followed by prolonged conservative management of the damaged distal tissue, in the hope of maximal tissue salvage. Increased physician awareness of this syndrome is mandatory for prevention, diagnosis, and early treatment.

Resting energy expenditure in Gaucher's disease type 1: effect of Gaucher's cell burden on energy requirements.

The resting energy expenditure (REE; kcal/d) of 25 patients with Gaucher's disease type 1 was determined by indirect calorimetry. The average observed REE for the group was approximately 44% greater (P less than .01) than that predicted (predicted REE) for these patient's age, sex, height, and weight. The increased caloric requirements of these patients was manifested by a height-for-age less than or equal to the fifth percentile in seven of nine growing children and a muscle mass of less than the fifth percentile in 15 of 19 patients studied. The excess REE (observed REE--predicted REE) for individual Gaucher's disease type 1 patients was directly related to their liver volume as estimated from radionuclide scans and to the mass of the spleen as measured at splenectomy. The relationship between spleen mass and excess REE was demonstrated by an average 22.0% decrease in REE following splenectomy in five patients. Based on these data, the metabolic rate of the splenic tissue removed from the patients was calculated to be 96.8 kcal/d/kg, about twofold to threefold less than that of normal splenic tissue. These findings indicate that the elevated REE observed in these patients resulted from the large mass of Gaucher's cells, which although individually hypometabolic, were cumulatively an excessive metabolic burden. Furthermore, they suggest that indirect calorimetry may be a quantitative tool for measuring disease progression and the effect of therapeutic intervention in Gaucher's disease type 1.

Distinguishing soft-tissue hemangiomas from vascular malformations using technetium-labeled red blood cell scintigraphy.

Soft-tissue vascular lesions in children can be classified as either hemangiomas or vascular malformations. The distinction between the two has important prognostic and therapeutic implications. Over the past 8 years, we have evaluated 64 vascular lesions with the technetium-labeled red blood cell (Tc-RBC) scan. Twenty-eight lesions imaged as hemangiomas with intense focal uniform uptake. This diagnosis was confirmed in 27 lesions, or 96 percent. Thirty-six lesions imaged as vascular malformations with abnormal vessels or diffusely increased activity. This diagnosis was confirmed in 35 lesions, or 97 percent. Overall, the Tc-RBC scan was 97 percent accurate in distinguishing hemangiomas from vascular malformations. It is particularly useful when the clinical diagnosis of the lesion may not be evident. Not only can biopsy be avoided, but parents can be reassured at an earlier age and given accurate information regarding prognosis.

Deaths following trauma: an audit of performance.

The TRISS methodology was applied to identify preventable trauma deaths in a retrospective audit of 267 (M = 0.908) patients admitted to a teaching hospital through the resuscitation room of its accident and emergency department during a 1-year period. No unexpected survivors were identified; of the 44 deaths (Z = 5.35), 25 (56.8%) were judged preventable by the TRISS method. Those deaths deemed preventable were subjected to peer review by a panel of six consultants. The findings are discussed in respect of recommendations made for UK trauma centre provision by the Working Party Report of the Royal College of Surgeons of England on the management of patients with major injuries.

Impact of implementing an EMR on physical exam documentation by ambulance personnel.

OBJECTIVES: Georgetown University has a student run Emergency Medical Services (EMS) organization with over 100 emergency medical technicians (EMTs). We set out to determine whether implementing an electronic patient care report (ePCR) system was associated with improved physical exam documentation. METHODS: This study evaluated documentation of the physical exam on prehospital patient care reports (PCRs). An ePCR system was implemented. ePCR documentation was compared to that of the previously used paper PCRs. This study looked retrospectively at 154 PCRs. 77 were hand written PCRs from before the electronic system. The PCRs involved chief complaints that were primarily respiratory, neurologic, or both. 77 ePCRs of matching chief complaint categories were used for comparison. Each chart was reviewed for completion of certain physical exam findings. The mean percentage of documented components from the ePCRs was compared to that of the hand written PCRs. The null hypothesis was that the absolute increase in the mean was not more than 20 percent. The two exclusion criteria were PCRs completed by study investigators after the design of the project and partially or completely missing PCRs. RESULTS: The absolute increase in mean physical exam component documentation was 36% (95% CI = 29-43%). A weighted kappa of 0.894 showed very good agreement between chart reviewers. CONCLUSIONS: This study rejected the null hypothesis that the ePCR system was associated with a mean increase of no more than 20%. It observed increase in physical exam documentation. Limitations of this study included the inability to determine whether documentation of physical exam findings reflected performance of the physical exam, and what components of the ePCR system bundle were responsible for the increase in physical exam component documentation.

Coupled translation and replication of poliovirus RNA in vitro: synthesis of functional 3D polymerase and infectious virus.

Poliovirus RNA polymerase and infectious virus particles were synthesized by translation of virion RNA in vitro in HeLa S10 extracts. The in vitro translation reactions were optimized for the synthesis of the viral proteins found in infected cells and in particular the synthesis of the viral polymerase 3Dpol. There was a linear increase in the amount of labeled protein synthesized during the first 6 h of the reaction. The appearance of 3Dpol in the translation products was delayed because of the additional time required for the proteolytic processing of precursor proteins. 3Dpol was first observed at 1 h in polyacrylamide gels, with significant amounts being detected at 6 h and later. Initial attempts to assay for polymerase activity directly in the translation reaction were not successful. Polymerase activity, however, was easily detected by adding a small amount (3 microliters) of translation products to a standard polymerase assay containing poliovirion RNA. Full-length minus-strand RNA was synthesized in the presence of an oligo(U) primer. In the absence of oligo(U), product RNA about twice the size of virion RNA was synthesized in these reactions. RNA stability studies and plaque assays indicated that a significant fraction of the input virion RNA in the translation reactions was very stable and remained intact for 20 h or more. Plaque assays indicated that infectious virus was synthesized in the in vitro translation reactions. Under optimal conditions, the titer of infectious virus produced in the in vitro translation reactions was greater than 100,000 PFU/ml. Virus was first detected at 6 h and increased to maximum levels by 12 h. Overall, the kinetics of poliovirus replication (protein synthesis, polymerase activity, and virus production) observed in the HeLa S10-initiation factor in vitro translation reactions were similar to those observed in infected cells.

Synchronous replication of poliovirus RNA: initiation of negative-strand RNA synthesis requires the guanidine-inhibited activity of protein 2C.

We report that protein 2C, the putative nucleoside triphosphatase/helicase protein of poliovirus, is required for the initiation of negative-strand RNA synthesis. Preinitiation RNA replication complexes formed upon the translation of poliovirion RNA in HeLa S10 extracts containing 2 mM guanidine HCI, a reversible inhibitor of viral protein 2C. Upon incubation in reactions lacking guanidine, preinitiation RNA replication complexes synchronously initiated and elongated negative-strand RNA molecules, followed by the synchronous initiation and elongation of positive-strand RNA molecules. The immediate and exclusive synthesis of negative-strand RNA upon the removal of guanidine demonstrates that guanidine specifically blocks the initiation of negative-strand RNA synthesis. Readdition of guanidine HCl to reactions synchronously elongating nascent negative-strand RNA molecules did not prevent their continued elongation and completion. In fact, readdition of guanidine HCl to reactions containing preinitiation complexes elongating nascent negative-strand RNA molecules had no effect on subsequent positive-strand RNA synthesis initiation or elongation. Thus, the guanidine-inhibited function of viral protein 2C was not required for the elongation of negative-strand RNA molecules, the initiation of positive-strand RNA molecules, or the elongation of positive-strand RNA molecules. The guanidine-inhibited function of viral protein 2C is required only immediately before or during the initiation of negative-strand RNA synthesis. We suggest that guanidine may block an irreversible structural maturation of protein 2C and/or RNA replication complexes necessary for the initiation of RNA replication.

Binding of the high mobility group protein, H6, to trout testis chromatin.

When 125I-labeled H6 was incubated with trout testis nuclei under conditions of pH and ionic strength approximating those in vivo, the radioactivity bound nearly quantitatively to the chromatin. Under comparable conditions, most non-nuclear proteins do not bind. Binding was neither tissue- nor species-specific, and HMG-17, a mammalian homolog of H6, behaved similarly to H6. The labeled and the endogenous H6 molecules were equivalent by several criteria: 1) Both were released nearly quantitatively upon treatment of the chromatin with DNase I, whereas neither was released by digestion with micrococcal nuclease, suggesting that the labeled molecules, like those of endogenous H6, were bound primarily to the core particles in transcriptionally competent portions of the genome. 2) Salt extraction curves were similar for both the labeled and unlabeled proteins, although about 15% of the labeled molecules were bound to the chromatin more loosely than those of the endogenous H6. Taken together, these results suggest that chromatin contains specific, well defined sites to which H6 binds. Upon increasing the concentration of H6 in the incubation mixture, progressively greater numbers of low affinity, presumably nonspecific binding sites become occupied. This observation has important implications for studies in which nucleases are employed to probe chromatin structure, since they suggest that H6 molecules released from specific, high affinity sites by the action of the nuclease might rebind more loosely to other regions of the chromatin.

Demonstration in vitro of temperature-sensitive elongation of RNA in Sindbis virus mutant ts6.

Characterization of conditionally lethal mutants of alphaviruses, Sindbis virus and Semliki Forest virus, has indicated that in almost all the RNA-negative mutants the temperature-sensitive (ts) defect prevents the formation of active transcription complexes at nonpermissive temperature (40 degrees C), but such complexes retain activity at 40 degrees C if formed first at permissive temperature (30 degrees C). Our recent results have extended the characterization of one exception to this finding: Sindbis ts6 transcription complexes, once formed at 30 degrees C, do not function at 40 degrees C. We used an in vitro assay for viral RNA synthesis to determine whether the ts defect was the result of dissociation of the complex or of a failure to elongate RNA chains in a stable complex. Our results indicated that the phenotype of ts6 observed in vivo was retained in vitro. In vivo incorporation into single-stranded 49S and 26S RNA was inhibited simultaneously with its incorporation into replicative intermediates upon shifting ts6-infected cells to 40 degrees C, which was compatible with a defect in elongation. Complexes formed at 30 degrees C and inactivated in vivo by shifting to 40 degrees C were reactivated by incubation in vitro at 30 degrees C but not at 40 degrees C. Thus, the transcription complexes were stable. Nascent RNA chains initiated in vivo and pulse-labeled in vitro were chased into single-stranded 49S and 26S RNA only when incubation was at 30 degrees C, indicating that the ts6 transcription complex was temperature sensitive in elongation. It should be possible to study in vitro other alphavirus RNA-negative mutants that demonstrate a change in viral RNA synthesis after shift to 40 degrees C. These would include ts mutants in the synthesis of subgenomic 26S mRNA and of minus-strand RNA.

Poly(rC) binding proteins mediate poliovirus mRNA stability.

The 5'-terminal 88 nt of poliovirus RNA fold into a cloverleaf RNA structure and form ribonucleoprotein complexes with poly(rC) binding proteins (PCBPs; AV Gamarnik, R Andino, RNA, 1997, 3:882-892; TB Parsley, JS Towner, LB Blyn, E Ehrenfeld, BL Semler, RNA, 1997, 3:1124-1134). To determine the functional role of these ribonucleoprotein complexes in poliovirus replication, HeLa S10 translation-replication reactions were used to quantitatively assay poliovirus mRNA stability, poliovirus mRNA translation, and poliovirus negative-strand RNA synthesis. Ribohomopoly(C) RNA competitor rendered wild-type poliovirus mRNA unstable in these reactions. A 5'-terminal 7-methylguanosine cap prevented the degradation of wild-type poliovirus mRNA in the presence of ribohomopoly(C) competitor. Ribohomopoly(A), -(G), and -(U) did not adversely affect poliovirus mRNA stability. Ribohomopoly(C) competitor RNA inhibited the translation of poliovirus mRNA but did not inhibit poliovirus negative-strand RNA synthesis when poliovirus replication proteins were provided in trans using a chimeric helper mRNA possessing the hepatitis C virus IRES. A C24A mutation prevented UV crosslinking of PCBPs to 5' cloverleaf RNA and rendered poliovirus mRNA unstable. A 5'-terminal 7-methylguanosine cap blocked the degradation of C24A mutant poliovirus mRNA. The C24A mutation did not inhibit the translation of poliovirus mRNA nor diminish viral negative-strand RNA synthesis relative to wild-type RNA. These data support the conclusion that poly(rC) binding protein(s) mediate the stability of poliovirus mRNA by binding to the 5'-terminal cloverleaf structure of poliovirus mRNA. Because of the general conservation of 5' cloverleaf RNA sequences among picornaviruses, including C24 in loop b of the cloverleaf, we suggest that viral mRNA stability of polioviruses, coxsackieviruses, echoviruses, and rhinoviruses is mediated by interactions between PCBPs and 5' cloverleaf RNA.

Solubilization and immunoprecipitation of alphavirus replication complexes.

Alphavirus replication complexes that are located in the mitochondrial fraction of infected cells which pellets at 15,000 x g (P15 fraction) were used for the in vitro synthesis of viral 49S genome RNA, subgenomic 26S mRNA, and replicative intermediates (RIs). Comparison of the polymerase activity in P15 fractions from Sindbis virus (SIN)- and Semliki Forest virus (SFV)-infected cells indicated that both had similar kinetics of viral RNA synthesis in vitro but the SFV fraction was twice as active and produced more labeled RIs than SIN. When assayed in vitro under conditions of high specific activity, which limits incorporation into RIs, at least 70% of the polymerase activity was recovered after detergent treatment. Treatment with Triton X-100 or with Triton X-100 plus deoxycholate (DOC) solubilized some prelabeled SFV RIs but little if any SFV or SIN RNA polymerase activity from large structures that also contained cytoskeletal components. Treatment with concentrations of DOC greater than 0.25% or with 1% Triton X-100-0.5% DOC in the presence of 0.5 M NaCl released the polymerase activity in a soluble form, i.e., it no longer pelleted at 15,000 x g. The DOC-solubilized replication complexes, identified by their polymerase activity in vitro and by the presence of prelabeled RI RNA, had a density of 1.25 g/ml, were 20S to 100S in size, and contained viral nsP1, nsP2, phosphorylated nsP3, nsP4, and possibly nsP34 proteins. Immunoprecipitation of the solubilized structures indicated that the nonstructural proteins were complexed together and that a presumed cellular protein of approximately 120 kDa may be part of the complex. Antibodies specific for nsP3, and to a lesser extent antibodies to nsP1, precipitated native replication complexes that retained prelabeled RIs and were active in vitro in viral RNA synthesis. Thus, antibodies to nsP3 bound but did not disrupt or inhibit the polymerase activity of replication complexes in vitro.

Complete replication of poliovirus in vitro: preinitiation RNA replication complexes require soluble cellular factors for the synthesis of VPg-linked RNA.

Translation of poliovirion RNA in HeLa S10 extracts resulted in the formation of RNA replication complexes which catalyzed the asymmetric replication of poliovirus RNA. Synthesis of poliovirus RNA was detected in unfractionated HeLa S10 translation reactions and in RNA replication complexes isolated from HeLa S10 translation reactions by pulse-labeling with [32P]CTP. The RNA replication complexes formed in vitro contained replicative-intermediate RNA and were enriched in viral protein 3CD and the membrane-associated viral proteins 2C, 2BC, and 3AB. Genome-length poliovirus RNA covalently linked to VPg was synthesized in large amounts by the replication complexes. RNA replication was highly asymmetric, with predominantly positive-polarity RNA products. Both anti-VPg antibody and guanidine HCl inhibited RNA replication and virus formation in the HeLa S10 translation reactions without affecting viral protein synthesis. The inhibition of RNA synthesis by guanidine was reversible. The reversible nature of guanidine inhibition was used to demonstrate the formation of preinitiation RNA replication complexes in reaction mixes containing 2 mM guanidine HCl. Preinitiation complexes sedimented upon centrifugation at 15,000 x g and initiated RNA replication upon their resuspension in reaction mixes lacking guanidine. Initiation of RNA synthesis by preinitiation complexes did not require active protein synthesis or the addition of soluble viral proteins. Initiation of RNA synthesis by preinitiation complexes, however, was absolutely dependent on soluble HeLa cytoplasmic factors. Preinitiation complexes also catalyzed the formation of infectious virus in reaction mixes containing exogenously added capsid proteins. The titer of infectious virus produced in such trans-encapsidation reactions reached 4 x 10(7) PFU/ml. The HeLa S10 translation-RNA replication reactions represent an efficient in vitro system for authentic poliovirus replication, including protein synthesis, polyprotein processing, RNA replication, and virus assembly.

Translating ribosomes inhibit poliovirus negative-strand RNA synthesis.

Poliovirus has a single-stranded RNA genome of positive polarity that serves two essential functions at the start of the viral replication cycle in infected cells. First, it is translated to synthesize viral proteins and, second, it is copied by the viral polymerase to synthesize negative-strand RNA. We investigated these two reactions by using HeLa S10 in vitro translation-RNA replication reactions. Preinitiation RNA replication complexes were isolated from these reactions and then used to measure the sequential synthesis of negative- and positive-strand RNAs in the presence of different protein synthesis inhibitors. Puromycin was found to stimulate RNA replication overall. In contrast, RNA replication was inhibited by diphtheria toxin, cycloheximide, anisomycin, and ricin A chain. Dose-response experiments showed that precisely the same concentration of a specific drug was required to inhibit protein synthesis and to either stimulate or inhibit RNA replication. This suggested that the ability of these drugs to affect RNA replication was linked to their ability to alter the normal clearance of translating ribosomes from the input viral RNA. Consistent with this idea was the finding that the protein synthesis inhibitors had no measurable effect on positive-strand synthesis in normal RNA replication complexes. In marked contrast, negative-strand synthesis was stimulated by puromycin and was inhibited by cycloheximide. Puromycin causes polypeptide chain termination and induces the dissociation of polyribosomes from mRNA. Cycloheximide and other inhibitors of polypeptide chain elongation "freeze" ribosomes on mRNA and prevent the normal clearance of ribosomes from viral RNA templates. Therefore, it appears that the poliovirus polymerase was not able to dislodge translating ribosomes from viral RNA templates and mediate the switch from translation to negative-strand synthesis. Instead, the initiation of negative-strand synthesis appears to be coordinately regulated with the natural clearance of translating ribosomes to avoid the dilemma of ribosome-polymerase collisions.

Preventable deaths after head injury: a clinical audit of performance.

A retrospective trauma audit of 267 consecutive patients presenting to the resuscitation room of an accident and emergency department identified 107 (M = 0.73) patients with CNS predominant injuries in a period of 1 year. The mortality rate was 33 per cent. Application of the TRISS method indicated that 18 (51 per cent) of the 35 deaths (Z = 5.74, P less than 0.001) were mathematically unexpected; no unexpected survivors were identified. Subsequent peer review agreed that death was preventable in 11 cases. The peer panel suggested that the lack of an on-site neurosurgical service may have affected the outcome of this group of patients adversely.

Malignant duodenocolic fistula. Report of a case and review of the literature.

Malignant duodenocolic fistulas are rare; the most common cause is carcinoma of the ascending or hepatic flexure of the right colon. Thirteen cases reported to date have been treated by right hemicolectomy combined with a Whipple procedure, with a 46 percent 2.5-year survival. A case is reported in which stapling devices facilitated an extended Whipple procedure.

5' cloverleaf in poliovirus RNA is a cis-acting replication element required for negative-strand synthesis.

A cloverleaf structure at the 5' terminus of poliovirus RNA binds viral and cellular proteins. To examine the role of the cloverleaf in poliovirus replication, we determined how cloverleaf mutations affected the stability, translation and replication of poliovirus RNA in HeLa S10 translation-replication reactions. Mutations within the cloverleaf destabilized viral RNA in these reactions. Adding a 5' 7-methyl guanosine cap fully restored the stability of the mutant RNAs and had no effect on their translation. These results indicate that the 5' cloverleaf normally protects uncapped poliovirus RNA from rapid degradation by cellular nucleases. Preinitiation RNA replication complexes formed with the capped mutant RNAs were used to measure negative-strand synthesis. Although the mutant RNAs were stable and functional mRNAs, they were not active templates for negative-strand RNA synthesis. Therefore, the 5' cloverleaf is a multifunctional cis-acting replication element required for the initiation of negative-strand RNA synthesis. We propose a replication model in which the 5' and 3' ends of viral RNA interact to form a circular ribonucleoprotein complex that regulates the stability, translation and replication of poliovirus RNA.

Poliovirus RNA recombination in cell-free extracts.

Poliovirus RNA has been shown to undergo homologous genetic recombination at a high frequency in infected human cells. Recently it has become possible to mimic the entire intracellular replicative cycle of poliovirus replication in cytoplasmic extracts prepared from HeLa cells, resulting in the generation of infectious poliovirions. The mechanism of poliovirus RNA recombination has been shown previously to be coupled to RNA replication, presumably by template switching during the replication of parental RNAs. Experiments were designed to test whether recombinant poliovirus RNA molecules are produced in a cell-free environment. Recombinant molecules generated bear marker sequences that can be detected physically by reverse transcription and PCR. We report here successful detection of poliovirus RNA recombination in a cell-free replication system. The frequency measured for cell-free RNA recombination between two polymorphic marker loci 656 nt apart was between 10(-2) and 10(-3) recombinants/genome, a frequency comparable to or slightly higher than that measured for RNA recombination in infected cells.

Poliovirus 5'-terminal cloverleaf RNA is required in cis for VPg uridylylation and the initiation of negative-strand RNA synthesis.

Chimeric poliovirus RNAs, possessing the 5' nontranslated region (NTR) of hepatitis C virus in place of the 5' NTR of poliovirus, were used to examine the role of the poliovirus 5' NTR in viral replication. The chimeric viral RNAs were incubated in cell-free reaction mixtures capable of supporting the sequential translation and replication of poliovirus RNA. Using preinitiation RNA replication complexes formed in these reactions, we demonstrated that the 3' NTR of poliovirus RNA was insufficient, by itself, to recruit the viral replication proteins required for negative-strand RNA synthesis. The 5'-terminal cloverleaf of poliovirus RNA was required in cis to form functional preinitiation RNA replication complexes capable of uridylylating VPg and initiating the synthesis of negative-strand RNA. These results are consistent with a model in which the 5'-terminal cloverleaf and 3' NTRs of poliovirus RNA interact via temporally dynamic ribonucleoprotein complexes to coordinately mediate and regulate the sequential translation and replication of poliovirus RNA.

Replication of poliovirus RNA and subgenomic RNA transcripts in transfected cells.

Full-length and subgenomic poliovirus RNAs were transcribed in vitro and transfected into HeLa cells to study viral RNA replication in vivo. RNAs with deletion mutations were analyzed for the ability to replicate in either the absence or the presence of helper RNA by using a cotransfection procedure and Northern (RNA) blot analysis. An advantage of this approach was that viral RNA replication and genetic complementation could be characterized without first isolating conditional-lethal mutants. A subgenomic RNA with a large in-frame deletion in the capsid coding region (P1) replicated more efficiently than full-length viral RNA transcripts. In cotransfection experiments, both the full-length and subgenomic RNAs replicated at slightly reduced levels and appeared to interfere with each other's replication. In contrast, a subgenomic RNA with a similarly sized out-of-frame deletion in P1 did not replicate in transfected cells, either alone or in the presence of helper RNA. Similar results were observed with an RNA transcript containing a large in-frame deletion spanning the P1, P2, and P3 coding regions. A mutant RNA with an in-frame deletion in the P1-2A coding sequence was self-replicating but at a significantly reduced level. The replication of this RNA was fully complemented after cotransfection with a helper RNA that provided 2A in trans. A P1-2A-2B in-frame deletion, however, totally blocked RNA replication and was not complemented. Control experiments showed that all of the expected viral proteins were both synthesized and processed when the RNA transcripts were translated in vitro. Thus, our results indicated that 2A was a trans-acting protein and that 2B and perhaps other viral proteins were cis acting during poliovirus RNA replication in vivo. Our data support a model for poliovirus RNA replication which directly links the translation of a molecule of plus-strand RNA with the formation of a replication complex for minus-strand RNA synthesis.