Negative pressure wound therapy versus gauze dressings for the treatment of contaminated traumatic wounds

OBJECTIVE

This compares hospital suction negative pressure wound therapy (NPWT) with conventional gauze dressings in traumatic soft-tissue injury at a tertiary care centre.

METHODS

A prospective control study was conducted between September 2012 and November 2014. Patients with one or more traumatic soft-tissue injuries with contaminated wounds were allocated to either a test group (received NPWT) or control group (received conventional gauze). Wounds were assessed by two orthopaedic surgeons. If grade A was achieved, the wound was covered with split-thickness skin graft, flap or delayed primary closure; otherwise, revision debridement and NPWT/saline gauze dressings were applied. Descriptive statistics (mean, standard deviation and proportions) were used to summarise the study variables. The 95% confidence intervals (CI) for difference of mean were used. Chi-square test and Fisher's exact test were used to observe an association between the qualitative data and outcome variables. Unpaired T-Test and Mann-Whitney U test were used for analysis of the quantitative data. A p<0.05 was considered statistically significant.

RESULTS

A total of 104 patients were included. The mean number of dressings per patient was significantly lower in the NPWT group (3.4) than in the control group (20.7) (p<0.001). The time between injury and complete closure (12.5 versus 21.4 days) as well as duration of hospital stay (17.3 versus 23.8 days) was significantly less in the NPWT group (p<0.05).

CONCLUSION

NPWT has a role in healing traumatic wounds and can be delivered effectively through hospital suction NPWT, which can also reduce the cost of therapy. We recommend its regular use in all patients presenting with post-traumatic, soft-tissue injuries when primary coverage is not possible.

Proteomic analyses of murine macrophages treated with Bacillus anthracis lethal toxin

Bacillus anthracis is the etiological agent of anthrax and the bacterium produces a tripartite anthrax toxin composed of protective antigen (PA), lethal factor (LF) and edema factor (EF). PA represents the binding domain of the toxin and acts in concert with either LF, a metalloprotease, or EF, an adenylate cyclase, to form lethal toxin (LeTx) or edema toxin (EdTx), respectively. We analyzed the proteomics response of two murine macrophage cell lines (J774.1A and RAW264.7) following B. anthracis LeTx treatment to detect unique host proteins involved in anthrax infection using difference in-gel electrophoresis (DIGE) followed by nanoLC-MS for identification of the proteins. The comparative proteomics approach identified a set of proteins in each cell line that was consistently upregulated when the two macrophage cell lines were treated with LeTx. The upregulated proteins include those involved in energy metabolism, cytoskeleton structure and stress response. A subset of five proteins (ATP synthase beta subunit, beta-actin, Hsp70, vimentin, and Hsp60 homolog) was identified that were commonly upregulated in both cell lines. The proteomic data suggest the involvement of reactive oxygen species (ROS) in cell lysis as seen by the upregulation of proteins that lead to the production of ROS in both the cell lines used in our study. However, proteins that afford protection against ROS may play an important role in the survival of the macrophage to LeTx infection as shown by the differences in proteomic responses of the two cell lines to the action of LeTx. These identified proteins may have the potential to be used as biomarkers for diagnostics and therapeutics.

Delayed occurrence of restenosis in drug eluting stents: an evidence of delayed healing

Drug eluting stents have made a significant impact on restenosis. However, there are concerns regarding delayed "catch-up" of restenosis. In this case report we present two such patients with delayed occurrence of restenosis after drug eluting stent implantation.

Coronary stent implantation without lesion predilatation (direct stenting): our experience with this evolving technique

BACKGROUND

Until recently, conventional intracoronary stent deployment required predilatation of the lesion with a balloon. However, "direct stenting" of the lesion without predilatation offers certain theoretical and practical advantages. We assessed the safety and feasibility of direct stenting in a select group of patients who were likely to benefit most from these advantages, namely, those with acute coronary syndromes. saphenous vein graft lesions, associated renal or left ventricular dysfunction and those requiring multivessel intervention.

METHODS AND RESULTS

After direct stenting, intravascular ultrasound was used to assess the adequacy of stent expansion in 51 patients. One hundred and twenty patients with a total of 125 lesions (83.3% males, average age 54.6+/-12.4 years) were enrolled for direct stenting. Of these, 90% of patients had presented with acute coronary syndromes, 21.6% of patients had associated moderate-to-severe left ventricular systolic dysfunction, 6.7% of patients had associated renal dysfunction and 30.8% of patients required multivessel intervention. Angiographically visible thrombus was present in 35.2% of patients. The mean reference diameter of the lesion was 3.18+/-0.32 mm and mean percentage diameter stenosis was 76.4+/-11.2%. Almost all varieties of stents were used (8.8% bare and 91.2% mounted). Procedural success was achieved in 98.3% of patients (98.4% of lesions). In two cases, the lesion had to be predilated prior to stenting. On angiography, the need for postdilatation of the stent was apparent in 29 (23.6%) lesions. In contrast, on intravascular ultrasound evaluation done in 51 lesions after stent deployment, the need for postdilatation to optimize stent expansion was seen in 43 (84.3%) lesions. There was one instance of acute stent thrombosis and two instances of slow-flow phenomenon. There were no deaths, myocardial infarction or need for urgent bypass surgery.

CONCLUSIONS

We conclude that direct stenting is feasible and safe in selected groups of patients. Optimization of stent expansion after direct stenting may often require aggressive postdilatation.

Key role for sulfur in peptide metabolism and in regulation of three hydrogenases in the hyperthermophilic archaeon Pyrococcus furiosus

The hyperthermophilic archaeon Pyrococcus furiosus grows optimally at 100 degrees C by the fermentation of peptides and carbohydrates. Growth of the organism was examined in media containing either maltose, peptides (hydrolyzed casein), or both as the carbon source(s), each with and without elemental sulfur (S(0)). Growth rates were highest on media containing peptides and S(0), with or without maltose. Growth did not occur on the peptide medium without S(0). S(0) had no effect on growth rates in the maltose medium in the absence of peptides. Phenylacetate production rates (from phenylalanine fermentation) from cells grown in the peptide medium containing S(0) with or without maltose were the same, suggesting that S(0) is required for peptide utilization. The activities of 14 of 21 enzymes involved in or related to the fermentation pathways of P. furiosus were shown to be regulated under the five different growth conditions studied. The presence of S(0) in the growth media resulted in decreases in specific activities of two cytoplasmic hydrogenases (I and II) and of a membrane-bound hydrogenase, each by an order of magnitude. The primary S(0)-reducing enzyme in this organism and the mechanism of the S(0) dependence of peptide metabolism are not known. This study provides the first evidence for a highly regulated fermentation-based metabolism in P. furiosus and a significant regulatory role for elemental sulfur or its metabolites.

Coronary stent thrombosis: time course and clinical outcome

The current clinical practice of stent implantation has changed over the last few years. We analysed the incidence and time course of stent thrombosis in patients undergoing successful coronary angioplasty and stenting over the last three years. All the patients were treated with aspirin and ticlopidine. A total of 13 patients experienced stent thrombosis. The mean age was 52+/-12 years; 12 were smokers and 10 had a recent history of myocardial infarction. None of these patients had received abciximab. The median time from stent implantation to stent thrombosis was 10 hours, with all the stent occlusions occurring within 18 hours of stent implantation procedure. All the patients underwent a repeat intervention at a median time of 30 minutes after the clinical suspicion of stent occlusion. On follow-up of 1 to 24 months, three patients developed reocclusion. In the present era of coronary angioplasty and stenting, when interventional procedures are not pre-planned and patients are treated with aspirin and ticlopidine or clopidogrel at the time of stent implantation, the incidence of stent thrombosis is low; it is seen mainly in patients with recent myocardial infarction, majority of them being smokers, and occurs within 18 hours in all the patients.

Multi-vessel coronary stenting--procedural results and late clinical outcomes: a comparison with single-vessel stenting

The purpose of this study was to assess the 1-year clinical outcome of patients with multi-vessel coronary artery disease (CAD) who underwent coronary stenting, and to compare the results with single-vessel coronary stenting carried out during the same period. We evaluated the in-hospital and 12-month clinical outcomes [death, Q-wave myocardial infarction (MI) and repeat revascularization rates at one year] in 384 consecutive patients treated with coronary stents in 2 (92% of patients) or 3 of the native coronary arteries and compared the outcome to 624 consecutive patients undergoing stenting in a single coronary artery between January 1, 1997 and January 31, 1999. The overall procedural success was obtained in 99% of patients with 2- or 3-vessel stenting and 98% of patients with single-vessel stenting. Procedural complications were similar (2.9% vs 2.6%; p = 0.12). During follow-up, target lesion revascularization was 16% in multi-vessel and 14% in single-vessel stenting (p = 0.38) and repeat revascularization was also similar for both groups (19% vs. 20%; p = 0.73). There was no difference in death (0.8% vs. 1.3%; p = 0.31) and Q-wave MI (0.7% vs. 1.4%; p = 0. 16) in the 2 groups. Overall cardiac event-free survival was similar for both groups (76% vs. 78%; p = 0.54). Multi-vessel stenting in carefully selected patients in our experience had a high procedural success with very low complication rates. The one-year clinical outcomes were acceptable and were similar to the results of single-vessel stenting.

Purification and characterization of a membrane-bound hydrogenase from the hyperthermophilic archaeon Pyrococcus furiosus

Highly washed membrane preparations from cells of the hyperthermophilic archaeon Pyrococcus furiosus contain high hydrogenase activity (9.4 micromol of H(2) evolved/mg at 80 degrees C) using reduced methyl viologen as the electron donor. The enzyme was solubilized with n-dodecyl-beta-D-maltoside and purified by multistep chromatography in the presence of Triton X-100. The purified preparation contained two major proteins (alpha and beta) in an approximate 1:1 ratio with a minimum molecular mass near 65 kDa and contained approximately 1 Ni and 4 Fe atoms/mol. The reduced enzyme gave rise to an electron paramagnetic resonance signal typical of the so-called Ni-C center of mesophilic NiFe-hydrogenases. Neither highly washed membranes nor the purified enzyme used NAD(P)(H) or P. furiosus ferredoxin as an electron carrier, nor did either catalyze the reduction of elemental sulfur with H(2) as the electron donor. Using N-terminal amino acid sequence information, the genes proposed to encode the alpha and beta subunits were located in the genome database within a putative 14-gene operon (termed mbh). The deduced sequences of the two subunits (Mbh 11 and 12) were distinctly different from those of the four subunits that comprise each of the two cytoplasmic NiFe-hydrogenases of P. furiosus and show that the alpha subunit contains the NiFe-catalytic site. Six of the open reading frames (ORFs) in the operon, including those encoding the alpha and beta subunits, show high sequence similarity (>30% identity) with proteins associated with the membrane-bound NiFe-hydrogenase complexes from Methanosarcina barkeri, Escherichia coli, and Rhodospirillum rubrum. The remaining eight ORFs encode small (<19-kDa) hypothetical proteins. These data suggest that P. furiosus, which was thought to be solely a fermentative organism, may contain a previously unrecognized respiratory system in which H(2) metabolism is coupled to energy conservation.

Elective stenting of extracranial carotid arteries

OBJECTIVES

In symptomatic and asymptomatic patients with significant carotid artery stenosis, surgical endarterectomy has been shown to be beneficial when compared with medical management. Carotid stenting is evolving as an alternative technique for treating such patients. This prospective study was designed to assess the feasibility and safety of carotid angioplasty and stenting.

METHODS

Fourteen patients (15 carotid arteries) with significant carotid artery stenosis were enrolled. These patients were in the age range 46 to 84 years (mean 60.9 +/- 7 years) and there were 12 males (86%). All of these patients were symptomatic with either TIA (n = 8) or stroke (n = 6). Wallstents were used in all the cases to stent the carotid arteries. One patient underwent bilateral carotid artery stenting.

RESULTS

Carotid angioplasty and stenting was successful in 13 out of 14 (92.8%) patients and 14 out of 15 (93.3%) carotid arteries, with reduction in mean (+/- SD) stenosis from 86 +/- 6% to 3 +/- 3%. There was one episode of minor stroke, no major stroke or death during the initial hospitalization. Another patient had a minor stroke with patent ipsilateral carotid artery (on repeat angiography) during the first 30 days after the procedure. This patient was also found to have asymptomatic thrombus formation in the contralateral carotid stent which resolved with intravenous anticoagulation. During a mean follow up of 6 +/- 2 months there has been no recurrence of symptoms.

CONCLUSIONS

Based upon our limited experience we believe that percutaneous carotid angioplasty with stenting is feasible with low periprocedural complication rate.

Percutaneous transluminal myocardial revascularization with a holmium laser system: Procedural results and early clinical outcome

Surgical transmyocardial laser revascularization has been reported to improve clinical outcome in patients with refractory angina who are not candidates for angioplasty or bypass surgery. We investigated the feasibility and safety of a nonsurgical, percutaneous technique for laser channel creation using energy from a holmium:yttrium-aluminium-garnet (YAG) laser. The laser energy was directed through a fiber enclosed in a catheter to the ventricular myocardium creating channels between the blood pool and the myocardium. Thirty-five patients with angina and coronary anatomy not amenable to revascularization with coronary angioplasty or bypass surgery underwent percutaneous transluminal myocardial revascularization. A total of 15 +/- 5 channels were formed per patient. There was no procedure-related mortality. One patient developed cardiac tamponade requiring thoracotomy and another a minor self-limiting pericardial effusion. There was no worsening of regional wall motion function in any patient. All patients were discharged alive after a postprocedure hospital stay of 2.1 +/- 1.4 days. Mean Canadian Cardiovascular Society (CCS) functional class declined from 3.68 +/- 0.4 before procedure to 0.82 +/- 0.7 at 30 days (P < 0.01). At 3 months, mean angina class was 0.94 +/- 0.65 (n = 35; P < 0.01) and at 6 months, mean angina class was 1.08 +/- 0.58 (n = 26; P < 0.01). One patient required repeat revascularization after 5 months for progression of disease in a degenerated saphenous venous graft supplying different region of myocardium. We conclude that transmyocardial revascularization using holmium:YAG laser by percutaneous technique can be carried out safely with encouraging early results and a very low complication rate. The symptomatic relief seen up to 6 months has been excellent. The long-term effects of this technique on mortality and relief of angina, however, remain to be defined. Cathet. Cardiovasc. Intervent. 47:287-291, 1999.

Primary stenting in acute myocardial infarction: a 30-day follow up study

Primary coronary stenting is being increasingly used in patients undergoing primary coronary angioplasty for acute myocardial infarction. In this prospective study we evaluated our experience of direct angioplasty in 68 patients with acute myocardial infarction of whom 57 received intracoronary stents using high-pressure deployment (> or =12 atmospheres) with adjunct aspirin and ticlopidine therapy without coumadin. All patients underwent pre-discharge follow-up angiography. Stent implantation was successful in all patients. Stent thrombosis was not seen in any patient. However, TIMI grade 3 flow was obtained in only 51 patients (89.6%) with evidence of slow flow present in remaining six patients. Follow-up angiograms showed no stent thrombosis but five out of the six patients (83%) with slow-flow phenomenon persisted to have slow flow. These patients had lower left ventricular ejection fraction as compared to patients with TIMI 3 flow at follow-up angiography (27.5 +/- 10.2% vs. 42.1 +/- 15.2%, P < .001) and a high mortality (two out of six) within 30 days. Primary stenting is safe and feasible in the majority of patients with good short-term outcomes, but persistent slow-flow phenomenon with adverse clinical outcome is seen in a small but significant number of patients.

Outcomes of primary stenting for acute myocardial infarction

Primary coronary stenting is being increasingly used in patients undergoing primary coronary angioplasty for acute myocardial infarction. In this prospective study we analysed our experience of direct angioplasty in 76 patients with acute myocardial infarction of whom 65 received intracoronary stents using high pressure deployment (> or = 12 atm) with adjunctive aspirin and ticlopidine therapy but without coumadin. All patients underwent pre-discharge angiography. Stent implantation was successful in all patients. Stent thrombosis was not seen in any patient. However, TIMI grade 3 flow was obtained in only 58 (89.2%) patients with evidence of slow-flow present in the remaining seven patients. Pre-discharge angiograms showed no-stent thrombosis but five out of the seven (71%) patients with slow-flow phenomenon persisted to have slow-flow. These patients had lower left ventricular ejection fraction as compared to patients with TIMI 3 flow at pre-discharge angiography (27.5 +/- 10.2% vs 42.1 +/- 15.2%; p < 0.001) and a high mortality (2 out of 7) within 30 days. Primary stenting is safe and feasible in the majority of patients with good short-term outcome. But persistent slow-flow phenomenon with adverse clinical outcome is seen in a small but significant number of patients.

Critical appraisal of left ventricular function assessment by the automated border detection method on echocardiography. Is it good enough?

Many studies have attempted to validate the echocardiographic automated border detection (ABD) method for assessing left ventricular ejection fraction (LVEF) by comparing it with various echocardiographic and non-echocardiographic standards. The main basis of assessing its accuracy has been the coefficient of correlation. The fallacy of using coefficient of correlation for assessing agreement between two methods of measurement has been well emphasized in the literature. In the present study we used the Bland and Altman test for testing the accuracy of the ABD method. We compared the ABD method for LVEF assessment with the manual edge detection technique on echocardiography and with radionuclide ventriculography in 34 patients. The majority of patients (76%) had regional wall motion abnormality. The ABD method could be adequately performed in 25 (74%) patients. LVEF was significantly underestimated by the ABD method with very wide limits of agreement when compared with radionuclide ventriculography and the manual edge detection technique (-9.2+/-21.7 and -2.7+/-18.4 respectively, mean error+/-2 standard deviations). Stated simply, the ABD method could overestimate LVEF by 12.5 and 15.7 or underestimate by 30.9 and 21.1 when compared with radionuclide ventriculography and manual edge detection technique, respectively. This large error is by no means acceptable for clinical purposes. It is concluded that at the present stage, the ABD method cannot replace radionuclide ventriculography and manual edge detection technique for assessing LVEF.

Acute haemodynamic effects of nicorandil in patients with chronic severe regurgitant valvular lesions

The haemodynamic effects of nicorandil, a new balanced vasodilator exhibiting nitrate-like as well as potassium-channel opening activity in patients with chronic severe valvular lesions have not been reported. We studied the acute effect of nicorandil on haemodynamics in 12 stable patients (6 males, 6 females; mean age 23.5 +/- 4.6 years) with chronic severe valvular regurgitation (8 mitral, 4 aortic). All patients were studied in resting, supine and fasting states. All cardioactive drugs were withdrawn five days prior to the study. Intra-arterial line was placed and thermodilution catheter was positioned in the pulmonary artery. Haemodynamic parameters recorded at baseline and at 30, 60, 90 and 120 minutes following a single oral dose of 20 mg nicorandil revealed no significant change in the heart rate while systemic pressures showed a small decline (p < 0.05). There was significant reduction in systolic, diastolic and mean pulmonary artery pressures (p < 0.001). The mean cardiac index increased from 3.16 L/min/m2 at baseline to 3.77 L/min/m2 at 60 minutes. Both the pulmonary and systemic vascular resistance indices reduced significantly, the peak fall being 18 percent and 29 percent, respectively. Maximal changes were observed at 60 to 90 minutes following administration of nicorandil. No adverse effect of nicorandil occurred during the study. We conclude that nicorandil has a favourable acute haemodynamic effect in patients with chronic severe valve regurgitation. Its long-term use in valvular lesions should be explored further.

DHR3, an ecdysone-inducible early-late gene encoding a Drosophila nuclear receptor, is required for embryogenesis

Response to the steroid hormone ecdysone in Drosophila is controlled by genetic regulatory hierarchies that include eight members of the nuclear receptor protein family. The DHR3 gene, located within the 46F early-late ecdysone-inducible chromosome puff, encodes an orphan nuclear receptor that recently has been shown to exert both positive and negative regulatory effects in the ecdysone-induced genetic hierarchies at metamorphosis. We used a reverse genetics approach to identify 11 DHR3 mutants from a pool of lethal mutations in the 46F region on the second chromosome. Two DHR3 mutations result in amino acid substitutions within the conserved DNA binding domain. Analysis of DHR3 mutants reveals that DHR3 function is required to complete embryogenesis. All DHR3 alleles examined result in nervous system defects in the embryo.

Use of activated partial thromboplastin time to monitor coumarin anticoagulation

The activated partial thromboplastin time after heparin removal (aPTT/HR) is an anionexchange procedure that permits the unobstructed monitoring of the progress of coumarin anticoagulation by removing interfering heparin. An all-intrinsic-pathway anticoagulant surveillance scheme based upon the aPTT/HR has been proposed and provisionally tested. The adoption of the new scheme will depend upon the identification of partial thromboplastins that are as predictable and reliable as the tissue thromboplastins in modern one-stage prothrombin times. In this study, the commercial APTT Reagent and Simplastin performed with equal sensitivity and specificity when evaluated by means of prothrombin group factor assays on coumarintreated subject plasmas. It is concluded that this commercial partial thromboplastin (1) is capable of being used for the purpose of following heparin, heparin plus coumarin, and coumarin anticoagulation; (2) is potentially able to identify more of the inherited and acquired derangements that can lead to anticoagulation-associated hemorrhage; and (3) is a universally available alternative to the traditional anticoagulant monitoring approach.