Assessing exposure to diesel exhaust particles: a case study

The assessment of the vehicular contributions to urban pollution levels is of particular importance given the current interest in the possible adverse health effects. This study focused on human exposure to diesel-engine-derived particulate matter. Diesel vehicles are known to emit fine particulate matter (PM2.5) containing carcinogens such as polycyclic aromatic hydrocarbons (PAHs), and have therefore received considerable attention. In this study, the physical (mass and number concentration, and size distribution) and chemical (PAHs) properties were investigated at a major bus interchange in Singapore, influenced only by diesel exhausts. Number concentration and size distribution of particles were determined in real time, while the mass concentrations of PM2.5, and PAHs were measured during operating and nonoperating hours. The average mass concentrations of PM2.5 and PAHs increased by a factor of 2.34 and 5.18, respectively, during operating hours. The average number concentration was also elevated by a factor of 5.07 during operating hours. This increase in the concentration of PM2.5 particles and their chemical constituents during operating hours was attributable to diesel emissions from in-use buses based on the particle size analysis, correlation among PAHs, and the commonly used PAHs diagnostic ratios. To evaluate the potential health threat due inhalation of air pollutants released from diesel engines, the incremental lifetime cancer risk was also calculated for a maximally exposed individual. The findings indicate that the air quality at the bus interchange poses adverse health effects.     

Plasma CRP level predicts left ventricular function and exercise capacity in patients with acute myocardial infarction

BACKGROUND: C-reactive protein estimation can help in predicting short- and long-term prognosis after acute myocardial infarction. High plasma C-reactive protein level in the acute phase strongly indicates a poor clinical outcome of the patients with myocardial infarction. METHODS AND RESULTS: One hundred consecutive patients admitted with ST elevation myocardial infarction in the intensive coronary care unit in our hospital who were able to do symptom-limited treadmill test during early recovery phase were studied. Plasma C-reactive protein was measured at the time of admission by immunoturbidity method. The normal value of the C-reactive protein was taken as 0.8 mg/dl. Echocardiographic study was done on day three of admission and ejection fraction was estimated by modified Simpson's method. Symptom-limited treadmill exercise test was done in all the patients. Patients were classified into two groups based on level of C-reactive protein: those with low C-reactive protein level (1.26 +/- 0.91 mg/dl, n=40) and those with high C-reactive protein level (6.52 +/- 3.97 mg/dl, n=60). Ejection fraction was lower in high C-reactive protein group (46.7 +/- 11.9%) compared to low C-reactive protein group (56.9 +/- 7.7%) (p = 0.011). Exercise capacity was lower in high C-reactive protein group (2.8 +/- 1.4 METs) compared to low C-reactive protein group (5.5 +/- 2.5 METs) p = 0.027). CONCLUSIONS: C-reactive protein levels are an index of the severity of myocardial necrosis which translate to worse left ventricular function. Higher the C-reactive protein level, lower the ejection fraction and worse may be the prognosis.     

Digital video-electroencephalographic monitoring in the neurological-neurosurgical intensive care unit: clinical features and outcome

BACKGROUND: Prolonged electroencephalographic (EEG) recordings in the neurological-neurosurgical intensive care unit (NICU) may be performed in patients with status epilepticus, repetitive seizure activity, or an encephalopathy with or without seizures. The electroclinical correlation and neurological outcome of patients undergoing digital video-EEG monitoring (DVEEG) in the NICU has not been determined. OBJECTIVES: To evaluate the clinical utility and prognostic importance of the DVEEG in the NICU. METHODS: We retrospectively evaluated 105 patients who underwent DVEEG in the NICU at the Mayo Clinic, Rochester, Minn, between January 1, 1994, and July 31, 2001. All patients had a routine EEG recording performed prior to DVEEG. RESULTS: The mean age of the patients at the time of the DVEEG was 54 years (age range, 16-88 years). The mean duration of the DVEEG was 2.9 days (range, 1-17 days). Forty-four patients (42%) had a severe encephalopathy (Glasgow Coma Scale score, <8) at the time of the DVEEG. Forty-five patients (42.8%) had generalized convulsive status epilepticus, 19 patients (18.1%) had nonconvulsive status epilepticus, and 7 patients (6.7%) had epilepsia partialis continua. The mean duration of follow-up was 7 months (range, 1-54 months). The outcome in 84 patients included death in 38 patients, severe neurological deficits, that is, bed bound and needs support for activities of daily living, in 6 patients, and a vegetative state in 3 patients. Fifteen individuals had no neurological impairment during follow-up. Refractory status epilepticus (P<.003), hypoxic-ischemic encephalopathy (P<.004), and multiple cerebral infarcts (P<.003) were the factors associated with increased mortality in univariate analysis. With multivariate logistic regression analysis only the presence of multiple strokes (P<.03; odds ratio, 5.62) was predictive of mortality. CONCLUSIONS: Continuous EEG monitoring is essential in the diagnosis and treatment of refractory status epilepticus or an encephalopathy with seizures in the NICU. A minority of these patients, however, experienced a favorable neurological outcome.     

Left ventricular twist mechanics in hypertrophic cardiomyopathy assessed by three-dimensional speckle tracking echocardiography

Left ventricular (LV) twist represents a phenomenon that links systolic contraction with diastolic relaxation and plays a major role in cardiac physiology; thus, the study of twist mechanics is of particular interest in hypertrophic cardiomyopathy (HC). Three-dimensional speckle tracking echocardiography (3D-STE) has the potential to overcome the limitations of 2-dimensional imaging and provide a greater understanding of LV twist in HC. We aimed to examine LV twist mechanics in HC using 3D-STE. Echocardiograms from subjects with a diagnosis of HC were examined for 3D-STE analysis. Age- and gender-matched healthy subjects were tested as a control group. Forty patients with HC (age 37 ± 16 years; 42.5% women) and 40 control subjects (age 35 ± 10 years; 42.5% women) were examined. Compared with the controls, the patients with HC showed increased peak LV twist (16.5 ± 4.7° vs 12.0 ± 3.9°, p <0.001) mainly because of increased apical rotation of those with LV outflow tract obstruction (obstruction, 12.7 ± 4.4° vs nonobstruction, 9.7 ± 2.8°, p = 0.02). In addition, the patients with HC displayed onset of torsion recoil occurring closer to the aortic valve closure (94 ± 6% vs 85 ± 6%, p <0.001; time normalized by the length of systole), limited completion of untwist during early diastole (31 ± 12% vs 62 ± 15%, p <0.001), and delayed peak untwist velocity (22 ± 7% vs 13 ± 9%, p <0.001; time normalized by the length of diastole). In conclusion, the evaluation of twist mechanics using 3D-STE provides novel insight regarding alterations in LV mechanics in patients with HC. Elucidating the characteristics of the wringing motion of the heart might help to broaden the understanding of the hyperdynamic contraction and impaired relaxation observed in these patients.     

Recent concepts in the management of extracranial carotid stenosis: carotid endarterectomy versus carotid artery stenting

Carotid stenosis is seen in 10% of patients with ischemic stroke, and carotid endarterectomy (CEA) and carotid artery stenting (CAS) are the two invasive treatments options available. Pooled analysis of the three largest randomized trials of CEA involving more than 3000 symptomatic patients estimated 30-day stroke and death rate at 7.1% after CEA. Some subgroups among the symptomatic patients appeared to have more benefit from CEA. These include patients aged 75 years or more, patients with ulcerated plaques, and patients with recent transient ischemic attacks within 2 weeks of randomization. Selection of asymptomatic patients for carotid revascularization should be guided by an assessment of comorbid conditions, life expectancy, and other individual factors, and should include a thorough discussion of the risks and benefits of the procedure with an understanding of patient preferences. The recent trials comparing CEA with CAS has not established its superiority over CEA. The carotid revascularization endarterectomy versus stenting (CREST) study showed that CAS is still associated with a higher periprocedural risk of stroke or death than CEA. In patients over 70 years of age, CEA is clearly superior to CAS. The increased risk of nonfatal myocardial infarction in the CREST group subjected to CEA clearly suggests that patients being considered for CEA or CAS require a careful preliminary cardiac evaluation. CAS can be justified for patients whose medical comorbidities or cervical anatomy make them questionable candidates for CEA. The benefit of revascularization by either method versus modern aggressive medical therapy has not been established for patients with asymptomatic carotid stenosis.     

Incidence and significance of pacemaker and implantable cardioverter-defibrillator lead masses discovered during transesophageal echocardiography

Background: Pacemaker and implantable cardioverter‐defibrillator device infections are feared complications. The finding of a lead‐associated mass on transesophageal echocardiogram (TEE) raises concern for endocarditis. However, the incidence and clinical importance of lead masses is not currently known. Methods: Consecutive patients with transvenous leads undergoing TEE from July 1, 2003, to June 30, 2005, were identified and assessed for a clinical diagnosis of endocarditis. An echocardiographer blinded to clinical information reviewed all TEEs. Results: Of 177 TEEs performed on 153 patients, a visible mass on a device lead was observed in 25 (14%), including 11 TEEs showing a lead vegetation, 13 TEEs showing lead strands, and one study showing both. Seventeen patients were adjudicated to have endocarditis, of which eight had a mass seen on a lead during TEE. Thus, 72% of patients (18 of 25) with a lead‐associated mass did not have evidence of an infection. In TEEs performed for indications other than to rule out endocarditis, lead masses were seen in 13 of 136 studies (10%), with only one patient adjudicated to clinically have an infected device. Conclusion: During this 2‐year study of consecutive patients with a tranvenous lead undergoing TEE, lead‐associated masses were found in 14% of patients. In 72% of patients, the mass did not prove to be secondary to infectious causes. Thus, masses attached to a device lead should be interpreted in the overall clinical context and, in the absence of concomitant evidence of endocarditis, should not mandate device and lead removal. (PACE 2011; 679–683)     

Guided bone regeneration with a synthetic biodegradable membrane: a comparative study in dogs

Objectives: The aim of the present study was to compare a newly developed biodegradable polylactide/polyglycolide/N‐methyl‐2‐pyrrolidone (PLGA/NMP) membrane with a standard resorbable collagen membrane (RCM) in combination with and without the use of a bone substitute material (deproteinized bovine bone mineral [DBBM]) looking at the proposed tenting effect and bone regeneration. Materials and methods: In five adult German sheepdogs, the mandibular premolars P2, P3, P4, and the molar M1 were bilaterally extracted creating two bony defects on each site. A total of 20 dental implants were inserted and allocated to four different treatment modalities within each dog: PLGA/NMP membrane only (Test 1), PLGA/NMP membrane with DBBM (Test 2), RCM only (negative control), and RCM with DBBM (positive control). A histomorphometric analysis was performed 12 weeks after implantation. For statistical analysis, a Friedman test and subsequently a Wilcoxon signed ranks test were applied. Results: In four out of five PLGA/NMP membrane‐treated defects, the membranes had broken into pieces without the support of DBBM. This led to a worse outcome than in the RCM group. In combination with DBBM, both membranes revealed similar amounts of area of bone regeneration and bone‐to‐implant contact without significant differences. On the level of the third implant thread, the PLGA/NMP membrane induced more horizontal bone formation beyond the graft than the RCM. Conclusion: The newly developed PLGA/NMP membrane performs equally well as the RCM when applied in combination with DBBM. Without bone substitute material, the PLGA/NMP membrane performed worse than the RCM in challenging defects, and therefore, a combination with a bone substitute material is recommended. To cite this article:
Jung RE, Kokovic V, Jurisic M, Yaman D, Subramani K, Weber FE. Guided bone regeneration with a synthetic biodegradable membrane: a comparative study in dogs.
Clin. Oral Impl. Res. 22 , 2011; 802–807
doi: 10.1111/j.1600‐0501.2010.02068.x     

Degloving injuries of the hand

Avulsion of skin from the hand or fingers is an injury that has a dramatic presentation. The entire musculo-skeletal unit of the finger is intact, and the patient can often move the parts of his naked hand quite normally. The challenge for the reconstructive surgeon lies in resurfacing the hand or finger with a good quality pliable sensate skin cover while preserving the movements and function of the hand. Traditionally, skin grafting has been the standard method of reconstruction in such injuries. However, skin grafting does have many disadvantages, too. This article deals with the features of such injuries, management protocols and other reconstructive options available in the armamentarium of the hand surgeon.KEY WORDS: Degloving injury, flap, hand surgery, hand injury, reconstruction