Transseptal puncture for left atrial ablation: risk factors for cardiac tamponade and a proposed causative classification system

Background

Cardiac tamponade is a high morbidity complication of transseptal puncture (TSP).

Purpose

We examined the associations of TSP-related cardiac tamponade (TRCT) for all patients undergoing left atrial ablation at our centre from 2016–2020.

Methods

Patient and procedural variables were extracted retrospectively. Cases of cardiac tamponade were scrutinised to adjudicate TSP culpability. Adjusted multivariate analysis examined predictors of TRCT.

Results

3,239 consecutive TSPs were performed; cardiac tamponade occurred in 51 patients (incidence: 1.6%) and was adjudicated as TSP-related in 35 (incidence: 1.1%; 68.6% of all tamponades). Patients of above-median age (OR 2.4 (1.19–4.2), p=0.006) and those undergoing re-do procedures (OR 1.95 (1.29–3.43, p=0.042) were at higher risk of TRCT. Of the operator-dependent variables, choice of transseptal needle (Endrys vs Brockenbrough, p>0.1) or puncture sheath (Swartz vs Mullins vs Agilis vs Vizigo vs Cryosheath, all p>0.1) did not predict TRCT. Adjusting for operator, equipment and demographics, failure to cross the septum first pass increased TRCT risk (OR 4.42 (2.45–8.2), p=0.001), whilst top quartile operator experience (OR 0.4 (0.17–0.85, p=0.002), transoesophageal echocardiogram (TOE prevalence: 26%, OR 0.51 (0.11–0.94), p=0.023), and use of the SafeSept guidewire (OR 0.22 (0.08–0.62), p=0.001) reduced TRCT risk. An increase in SafeSept wire use over time (2016: 15.6%, 2020: 60.2%) correlated with an annual reduction in TRCT (R2=0.72, p<0.001) and was associated with a relative risk reduction of 70%.

Conclusions

During left atrial ablation, the independent predictors of TRCT were patient age, re-do procedure, operator experience, unsuccessful first pass, TOE-guidance, and use of the SafeSept wire. A novel classification system for the causes of cardiac tamponade is proposed (table 1); this may be of interest to clinical trialists or auditors evaluating patient safety.

Funding Acknowledgement

Type of funding sources: None.

Transseptal puncture for left atrial ablation: risk factors for cardiac tamponade and a proposed causative classification system

Aims

Cardiac tamponade is a high morbidity complication of transseptal puncture (TSP). We examined the associations of TSP‐related cardiac tamponade (TRCT) for all patients undergoing left atrial ablation at our center from 2016 to 2020.

Methods and Results

Patient and procedural variables were extracted retrospectively. Cases of cardiac tamponade were scrutinized to adjudicate TSP culpability. Adjusted multivariate analysis examined predictors of TRCT. A total of 3239 consecutive TSPs were performed; cardiac tamponade occurred in 51 patients (incidence: 1.6%) and was adjudicated as TSP‐related in 35 (incidence: 1.1%; 68.6% of all tamponades). Patients of above‐median age [odds ratio (OR): 2.4 (1.19–4.2), p = .006] and those undergoing re‐do procedures [OR: 1.95 (1.29–3.43, p = .042] were at higher risk of TRCT. Of the operator‐dependent variables, choice of transseptal needle (Endrys vs. Brockenbrough, p > .1) or puncture sheath (Swartz vs. Mullins vs. Agilis vs. Vizigo vs. Cryosheath, all p > .1) did not predict TRCT. Adjusting for operator, equipment and demographics, failure to cross the septum first pass increased TRCT risk [OR: 4.42 (2.45–8.2), p = .001], whilst top quartile operator experience [OR: 0.4 (0.17–0.85), p = .002], transoesophageal echocardiogram [TOE prevalence: 26%, OR: 0.51 (0.11–0.94), p = .023], and use of the SafeSept transseptal guidewire [OR: 0.22 (0.08–0.62), p = .001] reduced TRCT risk. An increase in transseptal guidewire use over time (2016: 15.6%, 2020: 60.2%) correlated with an annual reduction in TRCT (R² = 0.72, p < .001) and was associated with a relative risk reduction of 70%.

Conclusions

During left atrial ablation, the risk of TRCT was reduced by operator experience, TOE‐guidance, and use of a transseptal guidewire, and was increased by patient age, re‐do procedures, and failure to cross the septum first pass.

The acute haemodynamic response with endocardial biventricular pacing: comparing RV paced and LBBB patients

Funding Acknowledgements

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Boston Scientific

Background

A third of patients that receive cardiac resynchronisation (CRT) are non-responders. Predictors of positive response include broader QRS duration, non-ischaemic aetiology and sinus rhythm, but it is still unclear whether lead placement site determines a positive responder.

Purpose

We assessed the acute haemodynamic response of endocardial biventricular pacing in patients with intrinsic left bundle brunch block (LBBB) versus LBBB due to pre-existing right ventricular pacing (RVP).

Methods

Patients who fulfilled standard criteria for CRT implantation but had failed conventional (coronary sinus) left ventricular (LV) lead placement (primary or revision) or were deemed clinical ‘non-responders after &gt; 6 months of conventional CRT were enrolled. The acute haemodynamic response during endocardial biventricular pacing was assessed with a roving LV lead at 9 different locations (basal and mid: septal, anterior, posterior and lateral walls and apex). Acute changes in beat-to-beat systolic blood pressure (SBP) in the left ventricle were recorded and analysed.

Results

We recruited 23 patients across 10 UK centres: 14 intrinsic LBBB and 9 dependent on RVP. Patient characteristics were comparable: age (mean 67 + 10.6 years vs. 62 + 15.4 years), ischaemic (63% vs 50%), QRS (160 + 18ms vs. 190 + 36ms, p =0.07). Of the RVP group 5/9 had septal RV leads (the remainder apically positioned).

There was no difference in the SBP improvement between the groups: change in SBP ranged from -5.25 – 19.91mmHg (median 3mmHg) in RVP patients vs -5.92 – 23.03mmHg (median 3mmHg) for intrinsic LBBB. However, the improvement in SBP was more consistent across the different segments in the patients with RVP (group A), as compared to intrinsic LBBB (group B), where the lateral wall and then non-septal walls provided the greatest haemodynamic improvement.

Figure 1: depicts SBP improvement (in mmHg) during endocardial biventricular pacing in different positions within the LV for patients with RVP (A) vs underlying intrinsic LBBB (B): 9 segment model of the LV: Ant (anterior wall), Lat (lateral wall), Post (posterior wall), Sept (septum). Outer ring represents the four basal LV locations, middle ring the mid LV locations and centre ring the apex. Scale depicts mmHg improvement in SBP.

Conclusion

When implanting an LV lead for patients who are RV pacing dependent any position within the LV provides an acute haemodynamic improvement, compared with those with intrinsic LBBB, where a targeted lateral wall approach is more important. This finding corroborates the key differences in LV activation patterns for induced versus intrinsic LBBB.

OVPSYCH2: A randomized controlled trial of psychological support versus standard of care following chemotherapy for ovarian cancer

BACKGROUND

Fear of disease progression (FOP) is a rational concern for women with Ovarian Cancer (OC) and depression is also common. To date there have been no randomized trials assessing the impact of psychological intervention on depression and FOP in this patient group.

PATIENTS AND METHODS

Patients with primary or recurrent OC who had recently completed chemotherapy were eligible if they scored between 5 and 19 on the PHQ-9 depression and were randomized 1:1 to Intervention (3 standardized CBT-based sessions in the 6-12 weeks post-chemotherapy) or Control (standard of care). PHQ-9, FOP-Q-SF, EORTC QLQ C30 and OV28 questionnaires were then completed every 3 months for up to 2 years. The primary endpoint was change in PHQ-9 at 3 months. Secondary endpoints were change in other scores at 3 months and all scores at later timepoints.

RESULTS

182 patients registered; 107 were randomized; 54 to Intervention and 53 to Control; mean age 59 years; 75 (70%) had completed chemotherapy for primary and 32 (30%) for relapsed OC and 67 patients completed both baseline and 3-month questionnaires. Improvement in PHQ-9 was observed for patients in both study arms at three months compared to baseline but there was no significant difference in change between Intervention and Control. A significant improvement on FOP-Q-SF scores was seen in the Intervention arm, whereas for those in the Control arm FOP-Q-SF scores deteriorated at 3 months (intervention effect = -4.4 (-7.57, -1.22), p-value = 0.008).

CONCLUSIONS

CBT-based psychological support provided after chemotherapy did not significantly alter the spontaneously improving trajectory of depression scores at three months but caused a significant improvement in FOP. Our findings call for the routine implementation of FOP support for ovarian cancer patients.

P3756Diverse activation patterns during persistent atrial fibrillation characterised by dipole density non-contact mapping

Background

Global simultaneous recording of activation during atrial fibrillation (AF) can elucidate underlying mechanisms contributing to AF maintenance. A better understanding of these mechanisms may allow for a personalised ablation strategy to treat persistent AF.

Purpose

To characterise left atrial endocardial activation patterns during AF using a novel non-contact dipole density mapping.

Methods

Activation patterns were characterised into three sub-types: (i) focal with centrifugal activation (FCA); (ii) localised rotational activation (LRA); (iii) localised irregular activation (LIA). Continuous activation patterns were quantified and distributed in the left atrium.

Results

A total of 144 persistent AF segments with 1068 activation patterns from 25 patients were analysed. The most common pattern was LIA (63%), which consist of four disparate features: slow conduction (45%), pivoting (30%), collision (16%) and acceleration (7%). LRA was the second commonest pattern (20%). FCA (17%) arose frequently from the PVs/ostia. Continuous AF activations comprise multiple combinations of FCA, LRA and LIA, transitioning from one to the next without a discernible order. Preferential conduction areas were typically seen in mid-anterior (48%) and lower-posterior (40%) walls where dominant activations were made up of LRA and LIA.

Conclusion

AF is characterised by heterogenous activation patterns that vary between individuals. Clinical implications of individualised ablation strategies guided by dipole density mapping will have to be determined.

Acknowledgement/Funding

None

The effect of strict infection control policies on the rate of infection after elective foot and ankle surgery

The rate of surgical site infection after elective foot and ankle surgery is higher than that after other elective orthopaedic procedures.

Since December 2005, we have prospectively collected data on the rate of post-operative infection for 1737 patients who have undergone elective foot and ankle surgery. In March 2008, additional infection control policies, focused on surgical and environmental risk factors, were introduced in our department.

We saw a 50% reduction in the rate of surgical site infection after the introduction of these measures. We are, however, aware that the observed decrease may not be entirely attributable to these measures alone given the number of factors that predispose to post-operative wound infection.

Cite this article: Bone Joint J 2015;97-B:516–19.

Changes in arthroscopic findings in the anterior cruciate ligament deficient knee prior to reconstructive surgery

We retrospectively compared the arthroscopic findings of 75 patients at the time of diagnosis of ACL rupture and the findings at the time of ACL reconstruction. We found that in the ACL deficient knee the deterioration in meniscal tears and osteochondral lesions was statistically greater with increased interval between diagnosis of ACL rupture and reconstruction. This study implies that in those patients where ACL reconstruction is indicated, a delay in reconstructive surgery can have a deleterious effect on the articular surface of the knee.

The influence on human osteoblasts in vitro of non-steroidal anti-inflammatory drugs which act on different cyclooxygenase enzymes

There is increasing evidence that non-steroidal anti-inflammatory drugs (NSAIDs) can adversely affect bone repair. We have, therefore, studied the in vitro effects of NSAIDs, which differentially inhibit cyclooxygenases (COX), the prostaglandin/thromboxane synthesising enzymes, on human osteoblasts. Indomethacin and the new nitric oxide (NO)-donating NSAIDs block the activity of both COX-1 and COX-2. Indomethacin and 5,5-dimethyl-3-(3 fluorophenyl)-4-(4 methylsulphonal) phenyl-2 (5H)-furanone (DFU) reduced osteoblast numbers in a dose-dependant manner and increased collagen synthesis and alkaline phosphatase activity. The reduction in osteoblast numbers was not caused by loss of adhesion and was reversible. Neither NSAID influenced DNA synthesis. There was no difference between the effects of indomethacin and DFU. NO-NSAIDs did not affect cell numbers. These results suggest that care should be taken when administering NSAIDs to patients with existing skeletal problems and that NO-NSAIDs may be safer.

Peptide insertions in domain 4 of hbeta(c), the shared signalling receptor subunit for GM-CSF, IL3 and IL5, induce ligand-independent activation

A mutant form of the common beta-subunit of the GM-CSF, interleukin-3 (IL3) and IL5 receptors is activated by a 37 residue duplicated segment which includes the WSXWS motif and an adjacent, highly conserved, aliphatic/basic element. Haemopoietic expression of this mutant, hbeta(c)FIDelta, in mice leads to myeloproliferative disease. To examine the mechanism of activation of this mutant we targetted the two conserved motifs in each repeat for mutagenesis. Here we show that this mutant exhibits constitutive activity in BaF-B03 cells in the presence of mouse or human GM-CSF receptor alpha-subunit (GMRalpha) and this activity is disrupted by mutations of the conserved motifs in the first repeat. In the presence of these mutations the receptor reverts to an alternative conformation which retains responsiveness to human IL3 in a CTLL cell line co-expressing the human IL3 receptor alpha-subunit (hIL3Ralpha). Remarkably, the activated conformation is maintained in the presence of substitutions, deletions or replacement of the second repeat. This suggests that activation occurs due to insertion of extra sequence after the WSXWS motif and is not dependent on the length or specific sequence of the insertion. Thus hbeta(c) displays an ability to fold into functional receptor conformations given insertion of up to 37 residues in the membrane-proximal region. Constitutive activation most likely results from a specific conformational change which alters a dormant, inactive receptor complex, permitting functional association with GMRalpha and ligand-independent mitogenic signalling.

Molecular aspects of polycythemia vera (review)

Polycythemia vera (PV) is a rare, progressive myeloproliferative disorder thought to originate from the clonal expansion of a multipotent haemopoietic stem cell. This disease is characterised by hyperproliferation of the erythroid, myeloid and megakaryocyte lineages in the early phase, anaemia and fibrosis in the spent phase, and with a significant number of patients developing acute myeloid leukaemia (AML) in the final phase. Studies investigating the growth factor requirements of committed progenitors have shown hypersensitivity to a number of haemopoietic growth factors (HGF) in vitro and several HGF receptor and signalling molecule alterations have been reported. The findings to date, however, are unable to account for the transformation of a primitive stem cell and the many alterations to growth factor responses seen in PV progenitors. Identification of the primary lesion that leads to the pathogenesis of PV is of major importance given the profound effects on regulation of the haemopoietic stem cell compartment. In this article we focus on characteristics of the disease, research findings to date and possible mechanisms to explain altered growth factor responses, receptor alterations and signalling abnormalities in PV.

Effects of benzoyl peroxide on lipogenesis in sebaceous glands using an animal model

BACKGROUND

Benzoyl peroxide is the most widely used topical agent for acne since the 1960s. Concomitant treatment of benzoyl peroxide with oral, or topical antibiotics diminishes the multiplication of antibiotic-resistant strains of Propionibacteria acnes. Besides being antibacterial, the chemical also functions as a peeling agent, has comedolytic activity, reduces free fatty acid levels, and is touted to be sebosuppressive.

OBJECTIVE

The purpose was to determine the ability of topically applied benzoyl peroxide to suppress lipogenesis of the sebaceous glands.

METHODS

The data were obtained employing an animal model for human sebaceous glands, namely, the flank organs of female golden Syrian hamsters.

RESULTS

Our results reveal no inhibition of lipogenesis in sebaceous glands by topical application of benzoyl peroxide.

CONCLUSION

Despite many functions beneficial in acne therapy, benzoyl peroxide does not possess sebosuppressive capabilities. With the advent of water-soluble organic peroxides revealing similar antimicrobial activity to benzoyl peroxide, all therapeutic parameters (save for sebosuppression) will need to be assessed to weigh the benefits of these second-generation acne-fighting peroxides.

SH3 domain-mediated interactions involving the phox components of the NADPH oxidase

OBJECTIVE AND DESIGN

To derive a model describing the SH3 domain-mediated assembly of the activated NADPH oxidase.

MATERIALS

Recombinant SH3 domain and Pro-rich fusion proteins were used to investigate potential co-associations.

METHODS

Interactions were assessed using biotinylated overlay assays and the yeast two hybrid system. Association with p47phox from cell lysates was examined by immunoblot analysis.

RESULTS

The association between p47- and p22phox involves the SH3 domains of p47phox functioning in tandem. The Prorich motif in p47phox interacts with both p40phox and the COOH-terminal SH3 domain of p67phox.

CONCLUSIONS

In the resting cell, the Pro-rich motif of p47phox interacts with the SH3 domain of p40phox, which in turn associates with p67phox. Upon activation, the p47-p40phox regulatory complex dissociates, permitting the association of p47phox with the COOH-terminal SH3 domain of p67phox. This complex translocates to the plasma membrane and associates with cytochrome b558, via interaction of the tandem SH3 domains of p47phox with the p22phox Pro-rich motif.

Foreign body in the throat migrating through the common carotid artery

We present a 55-year-old lady who swallowed a 3 cm pointed metal foreign body whilst eating a sardine salad. The foreign body migrated from the hypopharynx through the parapharyngeal space and traversed the common carotid artery over a period of 12 days. The foreign body was removed by exploration of the neck.

The resilience of combinatorial structure at the word level: morphology in self-styled gesture systems

Combinatorial structure at both word and sentence levels is widely recognized as an important feature of language--one that sets it apart from other forms of communication. The purpose of these studies is to determine whether deaf children who were not exposed to an accessible model of a conventional language would nevertheless incorporate word-level combinatorial structure into their self styled communication systems. In previous work, we demonstrated that, despite their lack of conventional linguistic input, deaf children in these circumstances developed spontaneous gesture systems that were structured at the level of the sentence, with regularities identifiable across gestures in a sentence, akin to syntactic structure. The present study was undertaken to determine whether these gesture systems were structured at a second level, the level of the word or gesture--that is, were there regularities within a gesture, akin to morphological structure? Further, if intra-gesture regularities were found, how wide was the range of variability in their expression? Finally, from where did these intra-gesture regularities come? Specifically, were they derived from the gestures the hearing mothers produced in their attempt to interact with their deaf children? We found that all of the deaf children produced gestures that could be characterized by paradigms of handshape and motion combinations that formed a comprehensive matrix for virtually all of the spontaneous gestures for each child. Moreover, the morphological systems that the children developed, although similar in many respects, were sufficiently different to suggest that the children had introduced relatively arbitrary distinctions into their systems. These differences could not be traced to the spontaneous gestures their hearing mothers produced, but seemed to be shaped by the early gestures that the children themselves created. These findings suggest that combinatorial structure at more than one level is so fundamental to human language that it can be reinvented by children who do not have access to a culturally shared linguistic system. Apparently, combinatorial structure of this sort is not maintained as a universal property of language solely by historical tradition, but also by its centrality to the structure and function of language.

Primitive human hematopoietic progenitors adhere to P-selectin (CD62P)

P-selectin was shown to bind committed human hematopoietic progenitors (colony-forming unit-granulocyte-macrophage [CFU-GM] and burst-forming unit-erythroid [BFU-E]) as identified by their expression of the CD34 antigen and by in vitro clonogenic assays. In addition, P-selectin bound all precursors (pre-CFU) of committed myeloid progenitors assayed by their ability to sustain hematopoiesis in both conventional stroma-containing and stroma-free, cytokine-dependent systems. Binding of CD34+ cells to P-selectin was temperature-independent and shear-resistant, occurred only in the presence of divalent cations, was protease sensitive, and was completely blocked by anti-P-selectin antibody. Neuraminidase treatment of CD34+ cells completely abrogated their binding to P-selectin, implying a prominent role for sialic acid in the structure and function of the P-selectin ligand on hematopoietic progenitors. Monoclonal antibodies (MoAbs) CSLEX-1 and HECA-452, which identify carbohydrate epitopes involving sialic acid, bound to 33% and 35% of CD34+ cells, respectively, and included the majority of CFU-GM and pre-CFU. Three-color flow cytometric analysis showed a precise codistribution of CSLEX-1 and HECA-452 antigens on CD34+ cells, implying recognition of the same glycoprotein antigen by the two MoAbs. Treatment of CD34+ cells with neuraminidase completely abolished binding of both MoAbs. In addition, HECA-452 partially blocked the adhesion of CD34+ cells to P-selectin. P-selectin glycoprotein ligand (PSGL-1), recently molecularly cloned from the promyelocytic leukemia cell line HL60, was expressed by CD34+ cells as determined by reverse transcription polymerase chain reaction. Combined with the functional and biochemical characteristics, these data suggest that PSGL-1 may comprise an important P-selectin ligand expressed by primitive hematopoietic cells, but do not preclude the existence of additional P-selectin ligands on these cells.

Attitudes toward trauma care of surgeons practising in Ontario

OBJECTIVE

To assess the attitudes of practising surgeons in the province of Ontario toward issues in trauma care management.

DESIGN

A survey by questionnaire.

SETTING

The study was carried out in a university-affiliated hospital. The survey respondents generally practised in a nonteaching setting; 48% were over the age of 50 years; 81% worked in an institution with 24-hour in-house physician coverage for the emergency department.

SUBJECTS

All 2294 surgeons registered with the Ontario Medical Association were surveyed by completion and return of a questionnaire; 191 surgeons were registered in Ontario but were not practising in the province and were excluded from the survey. Questionnaires were completed by 575 surgeons, but 49 were no longer in active practice, so 526 responses form the basis of this analysis.

RESULTS

The response rate to the questionnaire was 27%. One-third of the respondents wished to treat no trauma patients at all; 47% believed that trauma patients had a negative impact on their surgical practice; only 19% considered that trauma patients had a positive impact. Surgeons had negative attitudes toward trauma because of the night and weekend profile of trauma, its effect on elective surgical practice, the poor rate of reimbursement for time spent in trauma management, and the potential medicolegal liability of trauma cases.

CONCLUSIONS

These results suggest that there are few surgeons in Ontario who are truly committed to providing care to the injured patient. Strategies to overcome the perceived negative aspects of trauma care must be addressed because a crisis in the availability of surgeons to provide this care seems inevitable.

Nouns and verbs in a self-styled gesture system: what's in a name?

A distinction between nouns and verbs is not only universal to all natural languages but it also appears to be central to the structure and function of language. The purpose of this study was to determine whether a deaf child who was not exposed to a usable model of a conventional language would nevertheless incorporate into his self-styled communication system this apparently essential distinction. We found that the child initially maintained a distinction between nouns and verbs by using one set of gestures as nouns and a separate set as verbs. At age 3:3, the child began to use some of his gestures in both grammatical roles; however, he distinguished the two uses by altering the form of the gesture (akin to morphological marking) and its position in a gesture sentence (akin to syntactic marking). Such systematic marking was not found in the spontaneous gestures produced by the child's hearing mother who used gesture as an adjunct to speech rather than as a primary communication system. A distinction between nouns and verbs thus appears to be sufficiently fundamental to human language that it can be reinvented by a child who does not have access to a culturally shared linguistic system.

Comparison of two promoters controlling expression of secreted or intracellular IL-1 receptor antagonist

IL-1R antagonist can be expressed as a secreted glycoprotein (sIL-1Ra) or as an intracellular nonglycosylated form (icIL-1Ra). The two isoforms only differ in their N-terminal sequences and are thought to originate, by selection of alternative first exons, from a single gene (IL-1RN). We have previously described a clone that encodes the exons and promoter for sIL-1Ra. In this work, we describe and characterize a clone that contains the further upstream, alternative first exon used to generate icIL-1Ra. Sequences upstream to this alternative exon are demonstrated to have promoter activity in the human colon epithelial cell line HT29, whereas the sIL-1Ra promoter has undetectable activity. Both the icIL-1Ra and sIL-1Ra promoters were active when transfected into THP-1 cells. Neither promoter was responsive to PMA or LPS when introduced into HT29 or THP-1 cells. Activity of the endogenous icIL-1Ra and sIL-1Ra promoters was also investigated. In agreement with the transfected icIL-1Ra promoter, the endogenous icIL-1Ra gene is active in HT29 cells, though induced by PMA. In contrast to the transfected icIL-1Ra promoter, the endogenous icIL-1Ra gene is inactive in THP-1 cells and induced by PMA. Our data complete the structure of the human IL-1RN gene, demonstrating that the two forms of IL-1Ra are produced from the same gene by use of alternative first exons. We also show that there are two distinct promoters that control IL-1Ra expression, that lie upstream to each alternative first exon.

Comparison of two promoters controlling expression of secreted or intracellular IL-1 receptor antagonist

IL-1R antagonist can be expressed as a secreted glycoprotein (sIL-1Ra) or as an intracellular nonglycosylated form (icIL-1Ra). The two isoforms only differ in their N-terminal sequences and are thought to originate, by selection of alternative first exons, from a single gene (IL-1RN). We have previously described a clone that encodes the exons and promoter for sIL-1Ra. In this work, we describe and characterize a clone that contains the further upstream, alternative first exon used to generate icIL-1Ra. Sequences upstream to this alternative exon are demonstrated to have promoter activity in the human colon epithelial cell line HT29, whereas the sIL-1Ra promoter has undetectable activity. Both the icIL-1Ra and sIL-1Ra promoters were active when transfected into THP-1 cells. Neither promoter was responsive to PMA or LPS when introduced into HT29 or THP-1 cells. Activity of the endogenous icIL-1Ra and sIL-1Ra promoters was also investigated. In agreement with the transfected icIL-1Ra promoter, the endogenous icIL-1Ra gene is active in HT29 cells, though induced by PMA. In contrast to the transfected icIL-1Ra promoter, the endogenous icIL-1Ra gene is inactive in THP-1 cells and induced by PMA. Our data complete the structure of the human IL-1RN gene, demonstrating that the two forms of IL-1Ra are produced from the same gene by use of alternative first exons. We also show that there are two distinct promoters that control IL-1Ra expression, that lie upstream to each alternative first exon.

An SH3 domain and proline-rich sequence mediate an interaction between two components of the phagocyte NADPH oxidase complex

Neutrophils possess a multicomponent NADPH oxidase system capable of producing large quantities of superoxide in a process known as the respiratory burst (1). Upon stimulation of a phagocytic cell, two cytosolic components of the oxidase, p67phox and p47phox, associate with a membrane-bound flavocytochrome b and a small GTP-binding protein to form a functional enzyme complex. Each of the Phox proteins contains two src homology 3 (SH3) domains, which are of unknown function but are potential mediators of protein-protein interactions between components of the activated oxidase. We have isolated a 47-kDa protein from lysates of differentiated HL60 cells that specifically bound to the carboxyl-terminal SH3 domain of p67phox and not to any other SH3 domain tested. This protein was identified as p47phox, and the putative SH3 domain binding site was located to a carboxyl-terminal proline-rich region. Proline-rich synthetic peptides based on this carboxyl-terminal region specifically inhibited the binding of p47phox to the carboxyl-terminal SH3 domain of p67phox, and sequential truncation defined a unique minimal sequence, which, although similar, does not match the consensus sequence defined for other SH3-binding proteins.

Attitudes of surgical residents toward trauma care: a Canadian-based study

Surgical residents (n = 330) registered in training programs in the province of Ontario, Canada were surveyed about their attitudes toward trauma care related issues. Questionnaires were returned by 48%. Overall, 84% felt that their clinical exposure to trauma was adequate; 78% noted that the emphasis placed on trauma topics in their educational programs was appropriate; 50% spend > 10% of their current clinical time in trauma care. Orthopedic residents (n = 43) were different; 79% devoted > 10% and 29% > or = 30% of their time to trauma. Future clinical activity in trauma as practicing surgeons was expressed by 83% of the trainees: 31% intended < 10%, 46% 10%-30%, and 6% > 30% of their future practices to be related to trauma. The major positive factors of trauma were the scope and excitement of trauma care. The major negative factors were the night/weekend activity and the time away from family. We are encouraged by the results of this survey in that a significant number of residents perceive trauma as a clinical endeavor to be incorporated into their future surgical practices.

Ultrasonic attenuation in fibroadenoma of the breast

Fifteen patients are described who attended out Breast Screening Programme, and were found to have sclerosed fibroadenomas, the imaging of which raised the possibility of carcinoma. In six of these a reflective zone between a mass lesion and distal acoustic shadowing might have been used to infer the benign diagnosis.