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At least 703 records · Page 39Linked to original sources
PubMed2003

Physical examination of the knee: a review of the original test description and scientific validity of common orthopedic tests.

OBJECTIVES: To present the original descriptions of common orthopedic physical examination maneuvers of the knee and then to review the literature to support the scientific validity of these tests. DATA SOURCES: MEDLINE (1970-2000) searches were performed, as were reviews of various musculoskeletal examination textbooks that describe physical examination maneuvers of the knee. These references were then reviewed for additional references and crossed back to the original description (when possible) of these named tests. STUDY SELECTION: All articles that discussed the sensitivity and specificity of the physical examination maneuvers were extracted. This information was reviewed for accuracy and then summarized. DATA EXTRACTION: Multiple MEDLINE and text searches were performed by using the terms of the test maneuver, the joint tested, and the term physical examination. Any article with this information was reviewed until the article describing the original description was found. Articles dating from that original article to the present were reviewed for information on the sensitivity and specificity of the test. DATA SYNTHESIS: Literature reviewing the sensitivity and specificity of the tests reviewed is summarized in text and table form. The Lachman test seems to be very sensitive and specific for the detection of anterior cruciate ligament tears. For posterior cruciate ligament tears, the posterior drawer test is also very sensitive and specific and is enhanced with other tests, such as the posterior sag sign. For meniscal tears, the McMurray test is very specific but has a very low sensitivity, whereas joint line tenderness has fairly good sensitivity but lacks good specificity. Although collateral ligament testing seems to be sensitive and specific, there is a lack of well-designed studies that scientifically validate the sensitivity and specificity of these tests. Common tests for patellofemoral pain and patellar instability lack sensitivity when correlated with pathologic operative findings. CONCLUSIONS: Most physical examination tests could be referenced back to an original description, with variable information on the sensitivity and specificity along with other information about the validity of these tests in clinical practice. To standardize how physical examinations are performed and compared, they should follow the original description or agreed-on standards. In addition, the significance of a physical examination finding must be understood to ensure that patients with knee complaints are accurately diagnosed and properly treated.

Biomechanical Phenomena↗
PubMed2005

[Cervical origin of the subclavian artery: echocardiographic diagnosis in patients with monosomy 22q11].

OBJECTIVE: To assess the sensitivity and specificity of echocardiography in the detection of anomalies of the subclavian artery (cervical origin, aberrant origin from the descending aorta or isolation) in patients with monosomy 22q11. METHOD: From 1/1998 until 03/2002 we examined 57 patients with conotruncal cardiac malformations. 30 patients had pulmonary atresia and ventricular septal defect (53 %), 13 interrupted aortic arch (23 %), 9 tetralogy of Fallot (16 %) and 5 common truncus arteriosus (9 %). Echocardiographic examination included identification of the laterality of the aortic arch as well as examination of the origin of the brachiocephalic vessels. The results were compared with angiographic and intraoperative findings. Median age at echocardiographic investigation was 74 days (range 1 d - 33.4 yrs.). RESULTS: Laterality of the aortic arch was assessed correctly in all patients. 20/57 patients had a right-sided aortic arch (35 %). Echocardiography detected all anomalies of the subclavian artery (14/57 patients, 25 %, sensitivity 100 %) and excluded these anomalies correctly in 43 patients (specificity 100 %). Exact classification of the anomaly of the subclavian artery was possible in 6/6 patients with a cervical origin of the artery and in 7/8 patients with aberrant origin from the descending aorta. Monosomy 22q11 was diagnosed in 21 patients (37 %). CONCLUSION: Echocardiography achieves a high sensitivity in the detection of anomalies of the subclavian artery. The diagnosis of cervical origin of the artery, in particular, can be easily established. As this anomaly appears to be a specific marker for monosomy 22q11, echocardiography facilitates reliable identification of these patients in clinical practice.

Adolescent↗
PubMed2000

Incidentally detected stenoses proximal to grafts originating below the common femoral artery: do they affect graft patency or warrant repair in asymptomatic patients?

OBJECTIVE: Stenoses in infrageniculate arteries proximal to a lower extremity vein graft may reduce flow velocity through the bypass graft and are thought to predispose to graft occlusion. Repair of these lesions has been recommended to preserve graft function. This study was undertaken to better define the natural history of grafts below inflow lesions and to evaluate the necessity of repair to preserve graft patency. METHODS: From 1994 through 1999, patients undergoing lower extremity vein grafts by a single surgeon at a university hospital and an affiliated teaching hospital were placed in a prospective protocol for proximal infrageniculate native artery and graft surveillance through use of duplex scanning. The records of those patients with grafts originating distal to the common femoral artery were evaluated; they form the basis for this report. Arteriograms were obtained before bypass grafting, and no patient had a stenosis greater than 50% diameter reduction proximal to the graft origin. Follow-up scans were obtained from the common femoral artery through the graft and outflow artery. The peak systolic velocity and velocity ratio in an infrageniculate native artery proximal to the graft origin were recorded, as were the location and the time interval since the bypass graft. Repair of these proximal lesions was not performed during the course of this study. Revision of the bypass graft or its anastomoses was undertaken according to preestablished duplex scan criteria. RESULTS: During this time, 288 autogenous infrainguinal bypass grafts were performed, of which 159 originated below the common femoral artery; of these, 74 were from the superficial femoral artery, 29 from the profunda femoris artery, 49 from the popliteal artery, and 7 from a tibial artery. The maximum peak systolic velocity proximal to the graft origin was more than 250 in 38 arteries (25%) and more than 300 in 26 arteries (16%). The velocity ratio was 3.0 or more in 32 arteries at the same location as the peak systolic velocity and 3.5 or more in 23 arteries (15%), confirming hemodynamically significant stenoses at these sites. The location of peak systolic velocity was the common femoral artery in 81 patients (51%), the superficial femoral artery in 50 (31%), the popliteal artery in 22 (14%), and a tibial artery in 6 (4%). Follow-up ranged from 8 to 60 months (mean, 35 months). During follow-up, 19 patients died, 18 with patent grafts. Overall, nine grafts occluded. One of the occluded grafts had a velocity ratio greater than 3.0; this may have contributed to graft thrombosis. The other occlusions resulted from an unrepaired graft lesion in 2 patients, graft infection in 2 patients, and graft ligation necessitated by below-knee amputation in 2 patients. No cause for the occlusion could be identified in two of the grafts (neither had evidence of proximal arterial stenosis). Assisted primary patency rates were 95% and 91% at 3 and 5 years, respectively. CONCLUSIONS: For grafts originating distal to the common femoral artery, stenoses proximal to the graft do not affect bypass graft patency and do not require repair to prevent graft occlusion. Surveillance of these lesions may therefore be unnecessary, inasmuch as the repair of proximal lesions should not be undertaken to preserve graft function.

Adult↗
PubMed2003

Multiple, recurring origins of aposematism and diet specialization in poison frogs.

Aposematism is the association, in a prey organism, of the presence of a warning signal with unprofitability to predators. The origin of aposematism is puzzling, because of its predicted low probability of establishment in a population due to the prey's increased conspicuousness. Aposematism is a widespread trait in invertebrate taxa, but, in vertebrates, it is mostly evident in amphibians, reptiles, and fishes. Poison frogs (Dendrobatidae) are one of the most well known examples of the co-occurrence of warning coloration and toxicity. This monophyletic group of mostly diurnal leaf-litter Neotropical anurans has both toxic/colorful and palatable/cryptic species. Previous studies suggested a single origin of toxicity and warning coloration, dividing the family in two discrete groups of primitively cryptic and more derived aposematic frogs. Recent molecular phylogenetic analyses using mostly aposematic taxa supported this conclusion and proposed a single tandem origin of toxicity and conspicuous warning coloration. By using expanded taxon and character sampling, we reexamined the phylogenetic correlation between the origins of toxicity and warning coloration. At least four or five independent origins of aposematism have occurred within poison frogs; by using simulations, we rejected hypotheses of one, two, or three origins of aposematism (P < 0.002). We also found that diet specialization is linked with the evolution of aposematism. Specialization on prey, such as ants and termites, may have evolved independently at least two times.

Animals↗
PubMed1985

A defective phage system reveals bacteriophage T4 replication origins that coincide with recombination hot spots.

Plasmid transduction mediated by bacteriophage T4 has been used to study putative T4 DNA replication origins cloned as inserts in the Escherichia coli plasmid pBR322. Two particular inserts from the T4 genome allow high-frequency plasmid transduction, suggesting that each insert might contain a T4 replication origin. T4 infection of these plasmid-containing cells produces large numbers of defective phage particles that contain long linear concatamers of the plasmid DNA. During a second cycle of infection, these defective phage genomes can be replicated better than normal phage chromosomes present in the same infected cell; consequently, the T4 DNA inserts must be functioning as replication origins. Both of these origins appear to utilize a previously unrecognized mode of T4 replication initiation. Moreover, each origin coincides with a major recombination hot spot in the phage genome, and therefore this mode of replication initiation seems to involve a local stimulation of homologous genetic recombination. From a purely practical standpoint, additional DNA fragments can be cloned in an origin-containing plasmid, allowing isolation of large amounts of any DNA sequence with the glucosylated hydroxymethylcytosine modifications of T4 DNA.

DNA Replication↗
PubMed1989

Simian virus 40 (SV40) large tumor antigen causes stepwise changes in SV40 origin structure during initiation of DNA replication.

We have studied structural changes in the simian virus 40 (SV40) replication origin induced by SV40 large tumor antigen (T antigen). T-antigen-induced changes in origin DNA conformation can be visualized as specific and discrete topologic changes in origin DNA minicircles. We discovered three origin-T-antigen complexes defined by changes in DNA linking number. These complexes probably reflected essential early steps in the initiation of DNA replication since their formation required DNA sequences that are necessary for DNA replication but do not affect T-antigen binding. There are striking parallels between the T antigen-origin interactions uncovered by this assay and the interactions between the DnaA, -B, and -C proteins and the Escherichia coli replication origin, suggesting a significant evolutionary conservation in the mechanisms that initiate DNA replication.

Adenoviruses, Human↗
PubMed1989

Overreplication of the origin region in the dnaB37 mutant of Bacillus subtilis: postinitiation control of chromosomal replication.

When the Bacillus subtilis dnaB37 mutant, defective in initiation, is returned to permissive temperature after accumulation of initiation proteins at 45 degrees C, we have shown, by extensive DNA.DNA hybridization analysis, that the origin region is replicated in excess (approximately 2-fold). However, this replication is limited to a region of about 120-175 kilobases on either side of the origin. This has been confirmed by autoradiographic analysis of the overreplicated region. During the second round of synchronized replication at 30 degrees C, replication in fact appears to resume from the stalled forks on either side of the origin. We propose that in B. subtilis, in addition to a first level of control at the origin, a second level of control exists downstream of the origin in order to limit overreplication of the chromosome. These two controls might normally be tightly coupled. We suggest that the second level of control is exerted through the reversible inhibition of replisome movement at specific regions on either side of the origin.

Bacillus subtilis↗
PubMed1990

Alpha and beta replication origins of plasmid R6K show similar distortions of the DNA helix in vivo.

Plasmid R6K contains inverted repeats of an approximately 100-base-pair sequence separated by 5.5 kilobases. These long inverted repeats (LIRs) occur within the alpha and beta origins of replication and are essential for origin function. In this study, primer-extension analysis of DNA modified in vivo by dimethyl sulfate or KMnO4 revealed that both alpha and beta LIRs acquire similar structural distortions of the DNA helix in a functional R6K replicon. These distortions were not seen in plasmids containing isolated LIR sequences. In the functional replicon, the dimethyl sulfate and KMnO4 hyperreactive sites appear on complementary strands and are located to one side of an internal palindromic sequence within the LIRs. This asymmetry coincides with the primary direction of DNA replication from alpha and beta origins in vivo. We also observed two intermediate structures when certain R6K cis- or trans-acting elements are missing. Sequences near the alpha origin are required for generation of the dimethyl sulfate hyperreactive sites, whereas sequences near the beta origin are responsible for the appearance of KMnO4 hyperreactive sites. We suggest that these structures represent a hierarchy that leads to a "locked" preinitiation complex, which functions to synchronize and determine the direction of replication from the alpha and beta replication origins in vivo.

Base Sequence↗
PubMed1993

Bovine papilloma virus (BPV)-encoded E2 protein enhances binding of E1 protein to the BPV replication origin.

The replication of bovine papilloma virus (BPV) DNA in vivo requires two viral-encoded proteins, E1 and E2, while all other proteins are derived from the host. We described previously the isolation of the E1 protein and showed that it contains multiple functions required for BPV DNA replication. The BPV transcription factor E2 was shown by others to stimulate BPV DNA replication in vitro. Here, we present results that account for the role of the E2 protein. The E1 protein bound selectively to the BPV minimal origin of replication. This process required MgCl2 and ATP for maximal efficiency. The E1 protein also catalyzed a BPV origin-dependent DNA unwinding reaction. In this report, we show that at low levels of E1 protein, origin binding could be stimulated up to 40-fold by the E2 protein, provided that the DNA contained an E2 binding site. Consistent with this result, the E2 protein stimulated the origin-specific unwinding reaction catalyzed by E1, but it had no effect on the nonspecific E1-catalyzed helicase activity. In the absence of an E2 binding site, both origin-dependent binding and unwinding reactions with the E1 protein were unaffected by the E2 protein. These results suggest that E2 participates in the initiation of BPV DNA replication by enhancing E1 binding to the BPV origin via DNA-protein and protein-protein interactions.

Animals↗
PubMed2002

The human cruciform-binding protein, CBP, is involved in DNA replication and associates in vivo with mammalian replication origins.

We previously identified and purified from human (HeLa) cells a 66-kDa cruciform-binding protein, CBP, with binding specificity for cruciform DNA regardless of its sequence. DNA cruciforms have been implicated in the regulation of initiation of DNA replication. CBP is a member of the 14-3-3 family of proteins, which are conserved regulatory molecules expressed in all eukaryotes. Here, the in vivo association of CBP/14-3-3 with mammalian origins of DNA replication was analyzed by studying its association with the monkey replication origins ors8 and ors12, as assayed by a chromatin immunoprecipitation assay and quantitative PCR analysis. The association of the 14-3-3beta, -epsilon, -gamma, and -zeta isoforms with these origins was found to be approximately 9-fold higher, compared with other portions of the genome, in logarithmically growing cells. In addition, the association of these isoforms with ors8 and ors12 was also analyzed as a function of the cell cycle. Higher binding of 14-3-3beta, -epsilon, -gamma, and -zeta isoforms with ors8 and ors12 was found at the G(1)/S border, by comparison with other stages of the cell cycle. The CBP/14-3-3 cruciform binding activity was also found to be maximal at the G(1)/S boundary. The involvement of 14-3-3 in mammalian DNA replication was analyzed by studying the effect of anti-14-3-3beta, -epsilon, -gamma, and -zeta antibodies in the in vitro replication of p186, a plasmid containing the minimal replication origin of ors8. Anti-14-3-3epsilon, -gamma, and -zeta antibodies alone or in combination inhibited p186 replication by approximately 50-80%, while anti-14-3-3beta antibodies had a lesser effect ( approximately 25-50%). All of the antibodies tested were also able to interfere with CBP binding to cruciform DNA. The results indicate that CBP/14-3-3 is an origin-binding protein, acting at the initiation step of DNA replication by binding to cruciform-containing molecules, and dissociates after origin firing.

Base Sequence↗
PubMed2001

Children's original thinking: an empirical examination of alternative measures derived from divergent thinking tasks.

Children's creative potential is often assessed using cognitive tests that require divergent thinking, such as the Torrance Tests of Creative Thinking (TTCT; E. P. Torrance, 1974, 1976, 1990). In this study the authors investigated the effect of various scoring systems on the originality index, evaluating the high intercorrelation of fluency and originality measures found in the TTCT scoring system and the applicability of TTCT scoring norms over time and across age groups. In 3 studies, the originality of elementary school children was measured using TTCT norms and various sample-specific scoring methods with the TTCT Unusual Uses of a Box test as well as social-problem-solving tasks. Results revealed an effect of scoring technique on creativity indices as well as on the reliability of originality scores and the relationship between originality and other ability measures. The usefulness of the various measures for understanding children's original thinking are discussed.

Child↗
PubMed2004

Country of origin, social support and the risk of small for gestational age birth.

AIMS: This study investigates the risk of small for gestational age (SGA) in relation to country of origin of the mother. The role of psychosocial resources, socioeconomic and lifestyle factors was examined in different causal models. METHODS: Among all pregnant nulliparous women in the city of Malmö, Sweden, who gave birth in 1991--92, 872 (87.7%) women completed a questionnaire during their first antenatal visit. The study was carried out among women whose pregnancies resulted in a singleton live birth (n = 826); 22% (n = 182) of these women were foreign-born. RESULTS: Fifty-five (6.7%) of the infants were classified as SGA, 37 (5.7%) of mothers of Swedish origin and 18 (9.7%) of foreign origin. SGA deliveries were much more prevalent among Middle East- and North Africa-born women (22%) and sub-Saharan-born women (15%). In all, women of foreign origin had increased odds for delivering SGA babies (OR = 1.8, 95% CI = 1.0,3.2). In a multivariate analysis psychosocial and socioeconomic factors explained 30% and 40%, respectively, of the increased SGA risk. Psychosocial factors seemed to be more prominent risk factors for SGA among mothers of foreign origin. A possible synergistic relation was demonstrated between foreign origin of the mother and low social anchorage. CONCLUSIONS: This study showed that psychosocial factors, most probably linked to a disadvantaged social situation, could be the theoretically most important focus for preventing SGA in immigrant women. This could also further support a hypothesis of a link between psychosocial stress and SGA in general. However, this should not exclude the need for intervention in the antenatal care system in terms of specially tailored support and education.

Adult↗
PubMed2001

MECP2 mutations in sporadic cases of Rett syndrome are almost exclusively of paternal origin.

Rett syndrome (RTT) is an X-linked neurodevelopmental disorder that apparently is lethal in male embryos. RTT almost exclusively affects female offspring and, in 99.5% of all cases, is sporadic and due to de novo mutations in the MECP2 gene. Familial cases of RTT are rare and are due to X-chromosomal inheritance from a carrier mother. We analyzed the parental origin of MECP2 mutations in sporadic cases of RTT, by analysis of linkage between the mutation in the MECP2 gene and intronic polymorphisms in 27 families with 15 different mutations, and we found a high predominance of mutations of paternal origin in 26 of 27 cases (P<.001). The paternal origin was independent of type of mutation and was found for single-base exchanges as well as for deletions. Parents were not of especially advanced age. We conclude that de novo mutations in RTT occur almost exclusively on the paternally derived X chromosome and that this is most probably the cause for the high female:male ratio observed in patients with RTT. Affected males recently have been described in a few cases of familial inheritance. Identification of the parental origin may be useful to distinguish between the sporadic form of RTT and a potentially familial form. This distinction will allow geneticists to offer more-specific counseling and discriminate between higher (maternal origin) and lower (paternal origin) recurrence risk.

Adult↗
PubMed2006

Polyploids with different origins and ancestors form a single sexual polyploid species.

Polyploidization is one of the few mechanisms that can produce instantaneous speciation. Multiple origins of tetraploid lineages from the same two diploid progenitors are common, but here we report the first known instance of a single tetraploid species that originated repeatedly from at least three diploid ancestors. Parallel evolution of advertisement calls in tetraploid lineages of gray tree frogs has allowed these lineages to interbreed, resulting in a single sexually interacting polyploid species despite the separate origins of polyploids from different diploids. Speciation by polyploidization in these frogs has been the source of considerable debate, but the various published hypotheses have assumed that polyploids arose through either autopolyploidy or allopolyploidy of extant diploid species. We utilized molecular markers and advertisement calls to infer the origins of tetraploid gray tree frogs. Previous hypotheses did not sufficiently account for the observed data. Instead, we found that tetraploids originated multiple times from extant diploid gray tree frogs and two other, apparently extinct, lineages of tree frogs. Tetraploid lineages then merged through interbreeding to result in a single species. Thus, polyploid species may have complex origins, especially in systems in which isolating mechanisms (such as advertisement calls) are affected directly through hybridization and polyploidy.

Animals↗
PubMed2006

Proceedings of the SMBE Tri-National Young Investigators' Workshop 2005. Reconstructing the origins and dispersal of the Polynesian bottle gourd (Lagenaria siceraria).

The origin of the Polynesian bottle gourd (Lagenaria siceraria), an important crop species in prehistoric Polynesia, has remained elusive. Most recently, a South American origin has been favored as the bottle gourd could have been introduced from this continent with the sweet potato by Polynesian voyagers around A.D. 1,000. To test the hypothesis of an American origin for the Polynesian bottle gourd, we developed seven markers specific to bottle gourd (two chloroplast and five nuclear). The nuclear markers were developed using a new technique where polymorphic inter simple sequence repeat (ISSR) markers are converted into single-locus polymerase chain reaction and sequencing markers--an approach that will be useful for developing markers in other taxa. All seven markers were sequenced in 36 cultivars of bottle gourd from Asia, the Americas, and Polynesia. The results support a dual origin for the Polynesian bottle gourd: the chloroplast markers are exclusively of Asian origin, but the nuclear markers show alleles originating in both the Americas and Asia. Because hybridization of Polynesian bottle gourds with post-European introductions cannot be excluded, ancient DNA from archaeological material will be useful for further elucidating the prehistoric movements of this species in Polynesia. This work has implications not only for the dispersal of the Polynesian bottle gourd but also for the domestication and dispersal of the species as a whole.

Cell Nucleus↗
PubMed1986

Xrep, a plasmid-stimulating X chromosomal sequence bearing similarities to the BK virus replication origin and viral enhancers.

The human X chromosome-linked fragment, "Xrep," was sequenced because it exerts a positive effect on plasmid growth in both E. coli and Saccharomyces cerevisiae. The sequence revealed three features similar to the human BK virus replication origin: Xrep has a true palindrome, CCTCC(T)3CCTCC, which is similar to "true" palindrome-like sequences found at the replication origins of polyoma [CCTC(T/C)10CTCC], BK [CCTC(A/G)8CCTCC] and SV40 [CCTCC(A)6GCCTCC] viruses. Twenty nucleotides away from the true palindrome, Xrep has the sequence GAATCCTATTCACTTTT while BK virus, the human analogue of SV40, has GAAATCCCTATTCTTTT in exactly the same position relative to the true palindrome. These two 17-mers differ only in the positions of two nucleotides comparing Xrep and BK virus. Also similar to the replication origins of DNA viruses, Xrep appears to have a cluster of enhancers adjacent to the origin-like sequences. Potent enhancer-like activity was detected in pSV1 X CAT/Xrep constructs. Xrep may originate from an endogenous virus, or from an X chromosomal replication origin.

Acetyltransferases↗
PubMed1988

The integration host factor of Escherichia coli binds to multiple sites at plasmid R6K gamma origin and is essential for replication.

Examination of the effect of the himA and himD mutants of E. coli on the maintenance of plasmid R6K has revealed that the gamma origin-containing replicons cannot be established in any of the mutants deficient in the production of E. coli Integration Host Factor (IHF). Contrary, the R6K derivatives containing other origins of the plasmid (alpha and/or beta) replicate in a host lacking functional IHF protein. We show that IHF protein binds specifically to a segment of the replication region which is essential for the activity of all three R6K origins. Mapping the IHF binding sequence with neocarzinostatin showed that the protein protects three segments of the origin: two strong binding sites reside within an AT-rich block, while the third, considerably weaker site is separated from the other two by a cluster of the seven 22 bp direct repeats. These seven repeats have been shown previously to bind the R6K-encoded initiator protein pi. We also demonstrate that the establishment of pi-origin complexes prior to IHF addition prevents the binding of the IHF protein to the gamma origin. The binding sequences of IHF and pi proteins do not overlap, therefore, we propose that the binding of pi protein alters the structure of the DNA and thereby prevents the subsequent binding of IHF protein.

Bacterial Proteins↗
PubMed1988

The site of origin of the intravascular electrocardiogram recorded from multiorificed intravascular catheters.

Successful retrieval of venous air emboli via central venous catheters requires accurate placement of the distal tip of the catheter. The distal tip of single-orificed central venous catheters can be precisely located using intravenous electrocardiography (IVECG). However, the site of origin of the IVECG complex with multiorificed central venous catheters is not well known. In this study, the site of origin of the IVECG complex deriving from the wire within a multiorificed Arrow Antecubital Central Venous Catheterization Kit, the same Arrow catheter type without wire, and a multiorificed Cook Bunegin-Albin CVP Kit was determined in ten anesthetized dogs. The IVECG was found to originate from the distal portion of the Arrow wire whether the distal tip of the wire was within the distal segment of the Arrow multiorificed catheter, at the tip of the catheter, or protruding several cm from the tip of the catheter. When the Arrow multiorificed catheter (without wire) was used to determine the IVECG, the mean site of origin of the IVECG was 1.7 +/- 1.2 cm (mean +/- SD) proximal to the distal catheter tip. When the Cook multiorificed catheter (without wire) was used to determine the IVECG, the mean site of origin of the IVECG was 2.5 +/- 0.6 cm proximal to the distal catheter tip. Knowledge of the site of origin of the IVECG with the Arrow and Cook multiorificed catheters should permit the distal tips of these catheters to be placed in locations where efficient retrieval of venous air emboli is likely.

Animals↗