Pixel-scale miniaturization of guided mode resonance transmission filters in short wave infrared.

The effects of miniaturization on theoretically predicted performance of dual-period guided mode resonance (GMR) transmission filters, which demonstrate immense potential for multispectral imaging in short wave infrared (SWIR), have been compared with experimental findings. With reducing filter size from 112 periods (90 µm) to 12 periods (10 µm), peak transmittance (Tpeak) of simulated and measured filters reduced gradually from 84% to 55% and from 76% to 65%, respectively, with a moderate change of 1 - 3 nm in full width at half maximum (FWHM). For 6 period filters (5 µm), simulations predict drastically reduced Tpeak = 14% accompanied by increase in FWHM by 12 nm. The Tpeak value is theoretically shown to increase to 46% with FWHM reduced by 7 nm upon placing metal reflectors at the optimum positions to increase the optical path length. Our findings indicate that four 5 µm × 5 µm size filters with metal reflectors designed for different resonance wavelengths can be used to form a single, 20 µm × 20 µm mosaic pixel for SWIR multispectral imaging.

Anterior spinal artery syndrome from type A aortic dissection in a patient with Marfan syndrome due to a novel fibrillin mutation.

Type A aortic dissection is a rare but important cardiac surgical emergency. Few reports exist in the literature describing anterior spinal artery syndrome as a presenting feature. We report a case of anterior spinal artery syndrome due to aortic dissection in a patient with Marfan syndrome caused by a novel fibrillin mutation. A 53-year old female presented with chest pain and sudden-onset paralysis. Neurological examination revealed normal upper limb examination, reduced lower limb power and reflexes but normal sensation. CT scanning revealed type A acute aortic dissection which was treated with emergent cardiac surgical repair. At clinic follow up 3 years later, signs of Marfan syndrome were opportunistically noted and genetic testing revealed a novel mutation in the Fibrillin 1 gene. This case emphasises the importance of a good initial clinical assessment, including thorough neurological examination, as well as a low threshold of clinical suspicion for an aortic dissection in such a constellation of symptoms. The importance of family history should also be emphasised given the coincidental diagnosis of Marfan syndrome in a first-degree relative. Furthermore, this case illustrates the classical signs of anterior spinal artery syndrome.

European real world trans-catheter aortic valve implantation: systematic review and meta-analysis of European national registries.

OBJECTIVE: Transcatheter aortic valve implantation (TAVI) has been adopted rapidly in Europe. TAVI national registries can augment understanding of technologies and represent real-world experience, providing further clinical insights. We undertook a meta-analysis of published European national TAVI registries to assess current results following TAVI in Europe. METHODS: Electronic databases were searched. The review focused on the comparison of the following TAVI strategies: transfemoral (TF) and transapical (TA) SAPIEN and CoreValve implantation. Individual event rates for outcomes of interest were pooled using a mixed effect model. RESULTS: Seven European national TAVI registries (UK, Swiss, Belgium, Italy, Spain, France, Germany) were identified, including a total of 9786 patients who received TF-SAPIEN (n = 2885), TA-SAPIEN (n = 2252) and CoreValve (n = 4649) implantation. Pooled incidence of 30-day mortality was 0.08% [95% Confidence Interval (CI): 0.05-0.11], 0.12% [95% CI: 0.07-0.19] and 0.06% [95% CI: 0.03-0.11] for TF-SAPIEN, TA-SAPIEN and CoreValve respectively (test for subgroup difference P = 0.18); there was high heterogeneity across European countries. Pooled incidence of stroke was comparable among the TAVI strategies (test for subgroup difference P = 0.79); the incidence of post-procedural moderate paravalvular leak ≥ 2 (P = 0.9) was similar across groups. CoreValve implantation was associated with an increased risk of pacemaker implantation (0.22 [95% CI: 0.19-0.26]; test for subgroup difference P < 0.0001). The lowest 30-day mortality was associated with TAVI performed in Spain (b coefficient -4.3; P = 0.03), in Italy (b coefficient -2.1; P < 0.0001), in UK (b coefficient -1.95; P = 0.01) and in France (b coefficient -2.8; P = 0.03). The German registry has the highest mortality for every TAVI strategy amongst all other European registries and especially for the TA-SAPIEN group. CONCLUSIONS: Transarterial TAVI approaches were associated with a low early mortality regardless of the type of device used. There was marked heterogeneity among European countries for early mortality.

Risk factors for mediastinitis following cardiac surgery: the importance of managing obesity.

BACKGROUND: Mediastinitis is a devastating complication of cardiac surgery. Previous studies have often observed small populations, been retrospective in design, and used a variety of definitions for mediastinitis. AIM: To identify risk factors for mediastinitis, and strategies to minimize its incidence. METHODS: A prospective cohort study of 4883 adult patients who underwent cardiac surgery between October 2003 and February 2009, comparing pre- and peri-operative risk factors, microbial aetiology, requirement for re-admission, length of stay and mortality between patients with and without mediastinitis. FINDINGS: Ninety (1.8%) patients were diagnosed with mediastinitis. Microbial aetiology was defined for 75 patients. Staphlyocococcus aureus was the most common isolate (30 episodes; 15 due to meticillin-resistant S. aureus). Univariate analysis revealed the following pre-operative factors associated with mediastinitis: age; body mass index; diabetes; modified logistic European System for Cardiac Operative Risk Evaluation score; urgent admission; and longer pre-operative stay (P < 0.05). Associated peri-operative factors were: combined coronary artery bypass grafting plus aortic valve replacement; longer aortic cross-clamp time; and longer cardiopulmonary bypass time (P < 0.005). Multi-variate analysis revealed that higher body mass index, combined coronary artery bypass grafting plus aortic valve replacement, and older age were associated with mediastinitis (P < 0.05). Mediastinitis was associated with re-admission to hospital, longer inpatient stay and reduced long-term survival (P < 0.05). CONCLUSION: Mediastinitis is associated with worse short-term outcomes (re-admission, length of stay) and reduced long-term survival. Obesity is the only modifiable pre-operative risk factor for mediastinitis. It may be possible to reduce risk through pre-operative weight loss programmes before elective surgery.

A case of rib fungal osteomyelitis.

Candida Osteomyelitis is uncommon.(1,2) It is associated with surgery, broad spectrum antibiotic use, central venous catheter insertion and immunosuppression.(2) We present a rare case of candidal rib osteomyelitis presenting initially with an innocuous skin lesion managed by extensive excision and reconstruction with minimal duration of post-operative antimicrobial therapy.

A proposed new imaging pathway for patients with suspected lung cancer.

AIMS: PET-CT scans are routinely performed in patients with lung cancer after investigation by chest x-ray (CXR) and CT scan, when these have demonstrated potentially curable disease. If the majority of patients with lung cancer potentially suitable for curative treatment could be identified earlier in the diagnostic pathway on the basis of CXR findings they could be referred for PET-CT imaging without a prior CT scan. We investigated the clinical and financial implications of adopting such a strategy. MATERIALS AND METHODS: The details of 1187 patients referred with suspected lung cancer between July 2006 and August 2009 were analysed. The initial CXR and subsequent imaging of patients fit for curative treatment (Performance Status 0/1, FEV1 > 1.0) were reviewed (n = 251). The clinical and financial implications of referring patients for first line PET-CT if deemed potentially curable based on CXR findings were assessed. RESULTS: 107 of 1187 patients had potentially curable lung cancer on PS, lung function, CT and PET-CT. 96 of these 107 patients (90%) were correctly identified on CXR. 149 patients overall were diagnosed as potentially curable on CXR. Referring suitable patients for an immediate PET-CT scan resulted in a reduction in the time to complete staging investigations. CONCLUSIONS: Early PET-CT scanning for patients with suspected lung cancer, potentially suitable for curative therapy could result in more efficient staging with little additional cost.

Maximizing survival potential in very high risk cardiac surgery.

The mean age and risk profile of patients referred for cardiac surgery is constantly increasing. Surgeons are now inclined to accept high-risk patients because interventional cardiology provides less invasive alternatives for an overlapping patient cohort. As risk profile increases so does hospital mortality. Patients who are difficult to wean from cardiopulmonary bypass and those who subsequently deteriorate into a low cardiac output state have mortality rates between 50% and 80%. In established cardiogenic shock, conventional treatment with inotropes, the intra-aortic balloon pump, or temporary circulatory support devices has not substantially improved survival. In the absence of the transplant option, more innovative circulatory support strategies are required to improve survival in the postcardiotomy setting.

Aortic valve replacement for late infective endocarditis after heart-lung transplantation.

Infective endocarditis is a rare but life-threatening complication of heart and heart-lung transplantation. We describe a 32-year-old woman who developed aortic valvular endocarditis following heart-lung transplantation. Enterococcus was the infective organism. The patient's condition was successfully managed using prolonged intravenous antibiotic therapy and aortic valve replacement.

Myocardial infarction causes increased expression but decreased activity of the myocardial Na+-Ca2+ exchanger in the rabbit.

Na+-Ca2+ exchanger (NCX) protein levels and activity were measured in myocardium from the basal region of the left ventricle of rabbit hearts with significant left ventricular dysfunction (LVD), 8-9 weeks after an apical infarction. NCX protein abundance was higher in the tissue homogenates (121 +/- 11%) and purified membrane fractions (143 +/- 12%) in the LVD compared to the sham-operated (sham) group. NCX mRNA was also higher in the LVD group (126%). Lower NCX protein expression was observed in the membrane fractions from the epicardium compared to the endocardium in both the sham and LVD groups. Transmembrane currents were recorded in isolated cardiomyocytes by single-electrode voltage clamp; [Ca2+]i was measured using Fura-2. Rapid application of 10 mmol l-1 caffeine was used to induce Ca2+ release from the sarcoplasmic reticulum. The subsequent NCX-mediated Ca2+ efflux rate constant was lower (70% of sham) in the LVD group. NCX currents were measured in cardiomyocytes dialysed with 250 nM Ca2+ (50 mmol l-1 EGTA). A lower NCX current (75% of sham) was observed in the LVD group. Lower NCX activity was also observed in cardiomyocytes isolated from the epicardium compared to the endocardium; a transmural difference that was also seen in the LVD group. Reduced activity despite increased protein expression may result from reduced Ca2+ sensitivity of the allosteric regulation of NCX. However, measurements indicated increased Ca2+ sensitivity in the LVD group. Cardiomyocytes from LVD hearts displayed a marked reduction in the transverse tubule area (59% of sham) and the surface area/volume ratio (80% of sham). Disrupted transverse tubule structure may contribute to the decrease in NCX activity despite increased protein expression in LVD.

The effect of heptanol on the electrical and contractile function of the isolated, perfused rabbit heart.

Changes in cardiac gap junction expression, such as those following myocardial infarction and produced in connexin knockout mice, are associated with a predisposition to arrhythmias. The present experiments investigated the effects of heptanol, a reversible gap junction inhibitor, on isolated Langendorff-perfused rabbit hearts. The introduction and withdrawal of heptanol inhibited both pressure generation and electrical conduction. These effects were completely reversible. Possible mechanisms for these findings were investigated through measurement of the concentration dependence of heptanol's effects upon conduction velocity and repolarization duration. Low concentrations of heptanol (less than 0.3 mM) caused small but significant increases in the delay between the stimulus (delivered to the basal septum) artefact and local activation of the left ventricle, as measured from bipolar electrogram (BEG) recordings. There was a steep increase in the latency between stimulus and left-ventricular activation at concentrations of heptanol above 0.3 mM. These findings are explicable by earlier reports of heptanol actions on gap junctions in vitro and modelling studies of the effects of reduced gap junction conductance on conduction velocity. Heptanol decreased repolarization duration, measured from the activation recovery interval (ARI) of BEGs, and monophasic action potential duration at 70% repolarization (MAPD70). Heptanol also reduced left-ventricular developed pressure (LVDP), and the maximum rates of contraction and relaxation of the left ventricle; these effects were concentration dependent and reversible. However, changes in ARIs, LVDP and the maximum rates of change of pressure lacked the steep response to 0.3-1.0 mM heptanol shown by the latency. These other effects are therefore likely to be mediated by cellular targets other than gap junctions. Perfusion of hearts with heptanol was also associated with a high incidence of arrhythmias. During premature stimulation protocols arrhythmias could be induced in hearts perfused with 0.1-0.3 mM heptanol but not at higher concentrations. This suggests that there is a critical range of slowed conduction that permits the development of re-entrant arrhythmias in the normal heart, although the effects of heptanol on repolarization duration may also contribute to its pro-arrhythmic activity.

Anal carcinoma: a 15-year retrospective analysis.

BACKGROUND: Using a 15-year experience in two teaching hospitals to illustrate the clinicopathologic, treatment and survival characteristics of cloacogenic and squamous cell carcinoma of the anus. METHOD: A retrospective analysis over a 15-year period from St Vincent's Hospital (SVH) and the Catholic Medical Center (CMC) in New York City. The patients in the study all had a diagnosis of either squamous or cloacogenic cell carcinoma of the anus. RESULTS: Cloacogenic and squamous cell carcinoma accounted for 2.5% of all large bowel cancers. In the population sample, 28/92 (30.4%) were of the cloacogenic type and 64/92 (69.6%) were of the squamous cell type. The male-to-female ratio was 1:1.5 in those with cloacogenic cancer and 1.8:1 in those with squamous cell carcinoma. The mean age of presentation was 57 +/- 2.8 years for the squamous cell carcinoma patients and 66.3 +/- 3.4 years in those with cloacogenic carcinoma (P < 0.02); 3/28 (10.7%) of patients with cloacogenic cancer were human immune deficiency virus (HIV) positive while 15/64 (23.4%) of the squamous cell cancer patients were HIV positive. The most common clinical presentation in both groups were rectal bleeding, pain, constipation and the presence of an anal mass. Of patients with squamous cell cancer 25% had evidence of infection with the human papilloma virus (HPV) while none of those with cloacogenic cancer had evidence of HPV infection (P < 0.0005). The treatment modality and survival were similar in both histologic groups. The most important factors that affect survival in both groups are female sex and stage of disease. CONCLUSION: Cloacogenic and squamous cell carcinoma account for only a small proportion of large bowel cancers. The squamous cell type is the more common type and presents at a younger age in both sexes. The squamous cell type is also more common in males and is associated with human papilloma and HIV infection. Treatment modality and survival is, however, similar in both histologic variants of anal cancer.

Successful thrombolysis for massive pulmonary embolism after pulmonary resection.

We report the successful use of thrombolysis for acute massive pulmonary embolism 2 days after right lower lobectomy for bronchial adenocarcinoma. Pulmonary angiography revealed extensive clot unsuitable for surgical embolectomy. A bolus infusion of recombinant tissue plasminogen activator produced an immediate improvement in the patient's hemodynamic state. There was substantial blood loss requiring the transfusion of 21 units of blood over the postoperative period. The patient made a successful recovery and remained well at 1 year.

Quality of life after transthoracic endoscopic sympathectomy for upper limb hyperhidrosis.

OBJECTIVE: To assess the outcome after transthoracic endoscopic sympathectomy (TES) for upper limb hyperhidrosis. DESIGN: Prospective cohort study. SETTING: District general hospital. SUBJECTS: Consecutive patients undergoing TES for upper limb hyperhidrosis over a fifteen month period. INTERVENTIONS: One-stage bilateral TES. MAIN OUTCOME MEASURES: Change in quality of life as shown by the Short Form-36 health assessment questionnaire. RESULTS: Sixteen patients (11 women and 5 men, median age 26 years) underwent operation without complications. At median follow-up of 6.2 months, symptomatic improvement was found in 26 of 32 limbs treated (82%). Truncal compensatory hyperhidrosis was reported by 13 patients but was severe in only three. There were significant improvements in social function (p = 0.01) and mental health (p = 0.025) as assessed by the SF-36. CONCLUSION: Despite a high incidence of compensatory hyperhidrosis, TES improved both the symptoms and overall quality of life in patients with upper limb hyperhidrosis.

Unsuspected rectal adenocarcinoma causing a urinoma.

A middle-aged man with a history of Hodgkin's disease presented with loin pain and microscopic hematuria. Radiologic studies demonstrated a urinoma secondary to ureteric obstruction at the pelvic brim. Percutaneous nephrostomy was performed to decompress the collection and a ureteric stent inserted to maintain drainage. Laparotomy revealed an unsuspected rectal adenocarcinoma. A metastatic deposit compressing the ureter had produced the urinoma. Metastatic colorectal carcinoma is a rare cause of urinoma.