Perioperative and long-term morbidity and mortality after above-knee and below-knee amputations in diabetics and nondiabetics

We performed a retrospective review of a vascular surgery quality assurance database to evaluate the perioperative and long-term morbidity and mortality of above-knee amputations (AKA, n = 234) and below-knee amputations (BKA, n = 720) and to examine the effect of diabetes mellitus (DM) (181 of AKA and 606 of BKA patients). All patients in the database who had AKA or BKA from 1990 to May 2001 were included in the study. Perioperative 30-day cardiac morbidity and mortality and 3-yr and 10-yr mortality after AKA or BKA were assessed. The effect of DM on 30-day cardiac outcome was assessed by multivariate logistic regression and the effect on long-term survival was assessed by Cox regression analysis. The perioperative cardiac event rate (cardiac death or nonfatal myocardial infarction) was at least 6.8% after AKA and at most 3.6% after BKA. Median survival was significantly less after AKA (20 mo) than BKA (52 mo) (P < 0.001). DM was not a significant predictor of perioperative 30-day mortality (odds ratio, 0.76 [0.39-1.49]; P = 0.43) or 3-yr survival (Hazard ratio, 1.03 [0.86-1.24]; P = 0.72) but predicted 10-yr mortality (Hazard ratio, 1.34 [1.04-1.73]; P = 0.026). Significant predictors of the 30-day perioperative mortality were the site of amputation (odds ratio, 4.35 [2.56-7.14]; P < 0.001) and history of renal insufficiency (odds ratio, 2.15 [1.13-4.08]; P = 0.019). AKA should be triaged as a high-risk surgery while BKA is an intermediate-risk surgery. Long-term survival after AKA or BKA is poor, regardless of the presence of DM.     

Right ventricular myocardial infarction: presentation and acute outcomes

Acute inferior wall myocardial infarction can be complicated by right ventricular myocardial infarction (RVMI), and the excess mortality cannot be fully explained by mechanical reasons. The authors try to systematically assess the incidence, clinical presentation and early outcomes of right ventricular infarction in a tertiary-care setup. Their study was a prospective observational series of consecutive patients with RVMI. All patients with acute inferior myocardial infarction (n=135) were enlisted. RVMI was diagnosed by > or = 1 mm ST elevation in lead V(4R) in a right-sided electrocardiogram. Right ventricular (RV) infarction occurred in 37% (n=50) of patients with acute inferior infarctions. Patients with isolated inferior infarction served as controls (n=85). Echocardiography was performed within 24 hours of admission. From both groups, 66% qualified for thrombolysis. The incidence of hypotension-bradycardia and heart blocks requiring pacing support was much higher in right ventricular infarction (n=21) than in inferior infarction (n=13). Clinically manifest RV dysfunction (raised jugular venous pulse [JVP], hypotension, tricuspid regurgitation) and right ventricular dilation detected by echocardiography were seen in only 13 patients. The in-hospital mortality rate was significantly higher (n=8, 16%) in right ventricular infarction group than in inferior infarction group (n=3, 3.5%). Right ventricular infarction was seen in a third of inferior myocardial infarctions (IMIs), but hemodynamically evident right ventricular dysfunction occurred in only a tenth of acute IMIs. Nevertheless, the acute in-hospital mortality rate of patients with right ventricular infarction was much higher than in those with inferior infarction owing to arrhythmic and mechanical complications.     

Efficacy and optimal dose of sildenafil in primary pulmonary hypertension

PURPOSE: We aimed to assess the effects of sildenafil and evaluate optimal dosing in primary pulmonary hypertension (PPH). Sildenafil selectively inhibits phosphodiesterase 5 (PDE5), which is abundant in pulmonary and penile tissue. This results in increasing nitric oxide (NO) at tissue level leading to pulmonary vasodilatation. SUBJECTS AND METHODS: Our study was a prospective study of sildenafil in 15 consecutive patients with severe symptomatic PPH of NYHA class III-IV. All patients were stabilized for a minimum period of 5 days with antifailure medications. Sildenafil was started at 50 mg twice daily for 4 weeks and increased to 100 mg bid for 4 more weeks in a step-up protocol. Primary end-points were change in Borg dyspnea index, NYHA class and 6-min walk distance, estimated at baseline 1, 2, 4 and 8 weeks. RESULTS: NYHA class (baseline 3.8 +/- 0.4 vs. 4 weeks 2.4 +/- 0.5, p = 0.002), Borg dyspnea index (8.1 +/- 1.7 vs. 4.4 +/- 1.9, p = 0.0007), 6-min walk distance (234 +/- 44 vs. 377 +/- 128 m, p = 0.001) and Pulmonary artery pressure (125 +/- 15 vs. 113 +/- 18 mm Hg p = 0.05) are significantly improved with sildenafil 50 mg bid at 4 weeks. Increasing the dose to 100 mg bid did not produce further benefit. Echocardiography parameters of right heart dimensions and functions did not change markedly in the study period. CONCLUSION: Sildenafil is well tolerated with no adverse effects in severe pulmonary hypertension. It reduces symptoms, improves effort tolerance and controls refractory heart failure significantly by 2 weeks in 70% of patients at 50 mg twice daily. Three patients (20%) failed to respond with sildenafil.     

Oxidative stress and endothelial dysfunction in vascular disease

In response to physiologic stimuli, endothelial cells dynamically regulate arterial vascular tone by producing vasodilators and vasoconstrictors. Risk factors for atherosclerosis, such as diabetes, smoking, hypercholesterolemia, and hypertension, interfere with this response, promoting endothelial dysfunction and atherosclerosis. This review explores whether oxidative stress might be a common feature of both endothelial dysfunction and atherosclerosis. Using biomarkers to assess endothelial function might provide insights into the pathways for oxidative stress in vascular disease. However, currently available markers of oxidative stress and endothelial function are unsuitable for routine clinical use because they are too expensive and inadequately validated. Thus, there is a need to develop and validate new markers that could be used to both measure oxidative stress and monitor therapies that specifically interrupt oxidative pathways in vascular tissue. Such markers might eventually help to identify susceptible individuals at a stage when cardiovascular complications could be prevented.     

Differential effects of IL-21 and IL-15 on perforin expression, lysosomal degranulation, and proliferation in CD8 T cells of patients with human immunodeficiency virus-1 (HIV)

An urgent need exists to devise strategies to augment antiviral immune responses in patients with HIV who are virologically well controlled and immunologically stable on highly active antiretroviral therapy (HAART). The objective of this study was to compare the immunomodulatory effects of the cytokines interleukin (IL)-21 with IL-15 on CD8 T cells in patients with HIV RNA of less than 50 copies/mL and CD4 counts greater than 200 cells/mm.(3) Patient CD8 T cells displayed skewed maturation and decreased perforin expression compared with healthy controls. Culture of freshly isolated patient peripheral-blood mononuclear cells (PBMCs) for 5 hours to 5 days with IL-21 resulted in up-regulation of perforin in CD8 T cells, including memory and effector subsets and virus-specific T cells. IL-21 did not induce T-cell activation or proliferation, nor did it augment T-cell receptor (TCR)-induced degranulation. Treatment of patient PBMCs with IL-15 resulted in induction of perforin in association with lymphocyte proliferation and augmentation of TCR-induced degranulation. Patient CD8 T cells were more responsive to cytokine effects than the cells of healthy volunteers. We conclude that CD8 T cells of patients with HIV can be modulated by IL-21 to increase perforin expression without undergoing overt cellular activation. IL-21 could potentially be useful for its perforin-enhancing properties in anti-HIV immunotherapy.     

A novel mutation in ferroportin1 is associated with haemochromatosis in a Solomon Islands patient

BACKGROUND: A severe form of iron overload with the clinicopathological features of haemochromatosis inherited in an autosomal dominant manner has been described in the Solomon Islands. The genetic basis of the disorder has not been identified. The disorder has similarities to type 4 haemochromatosis, which is caused by mutations in ferroportin1. AIMS: The aims of this study were to identify the genetic basis of iron overload in a patient from the Solomon Islands. PATIENT AND METHODS: Genomic DNA was isolated from peripheral blood leucocytes of a Solomon Islands man with severe iron overload. The entire coding region and splice sites of the ferroportin1 gene was sequenced. RESULTS AND CONCLUSIONS: A novel missense mutation (431A>C; N144T) was identified in exon 5 of the ferroportin1 gene. A novel restriction endonuclease based assay which identifies both the N144T and N144H mutations was developed which will simplify the diagnosis and screening of patients for iron overload in the Solomon Islands and other populations. This is the first identified mutation associated with haemochromatosis in the Solomon Islands population.     

Differences in participation of innate and adaptive immunity to respiratory syncytial virus in adults and neonates

Innate and adaptive immune responses to respiratory syncytial virus (RSV) in neonates were assessed by cord blood mononuclear cell (MC) cytokine expression and proliferation and these responses were compared with those from adult peripheral blood MCs. In adult cells, inactivated and live virus invoked cytokines reflecting both innate and adaptive immunity (interleukin [IL]-6, interferon [IFN]-gamma, IL-2, tumor necrosis factor [TNF]-alpha, and IL-10). Low levels of IL-4 were detected, although only with inactivated virus. In contrast, in neonatal cells, inactivated virus invoked large levels of the innate immune cytokines IL-6, TNF-alpha, and IL-10 and reduced levels of IFN-gamma and IL-12 but no adaptive cytokines. Live virus induced fewer innate (IL-6, IL-10, and IFN-gamma) and no adaptive immune cytokines. RSV-induced proliferation was absent in neonatal MCs, although positive in adult MCs. Thus, exposure to RSV does not appear to occur before birth, and adaptive immune insufficiency or greater innate responses may account for early life RSV-induced illnesses.     

Preliminary investigation on the antibacterial activity of mango (Mangifera indica L: Anacardiaceae) seed kernel

ObjectiveTo evaluate the antibacterial activity of the methanolic extract of mango (Mangifera indica L.) seed kernel.MethodsChokanan mango seed kernel and seed kernels from assorted mango varieties were collected, cleaned, dried and powered. Crude methanolic extracts of mango seed kernel were analyzed for the phytochemical constituents. The free radical scavenging activity was determined by 2,2-Diphenyl-1-picrylhydrazyl (DPPH) assay. Antibacterial activity was evaluated by disc diffusion assay with three medically important bacterial pathogens such as methicillin resistant Staphylococcus aureus (S. aureus) (MRSA), Escherichia coli (E. coli) and Vibrio vulnificus (V. vulnificus).ResultsQualitative phytochemical analysis indicated the presence of important phytochemical compounds such as glycosides, saponins, flavanoids, tannins and alkaloids. There was no significant difference in the phytochemical content between the single and assorted mango seed kernels. However, the free radical scavenging study indicated that the assorted mango kernels showed slightly higher activity than the single species (P <0.05). The crude methanolic extract of mango seed kernel at a concentration of 100 mg/mL is found to have potential antimicrobial activity against MRSA and E. coli compared to V. vulnificus. Study on the antibacterial activity also indicated that there was no significant difference in the antibacterial activity of the single and assorted mango seed kernel extracts.ConclusionsThe present study conclusively demonstrates the free radical scavenging activity and antibacterial activities of mango seed kernel. In addition, the results also indicated that there is no significant difference in the phytochemical content and biological activity of mango kernels from single and assorted mango varieties.     

From the Cover: 3D visualization of HIV transfer at the virological synapse between dendritic cells and T cells

The efficiency of HIV infection is greatly enhanced when the virus is delivered at conjugates between CD4⁺ T cells and virus-bearing antigen-presenting cells such as macrophages or dendritic cells via specialized structures known as virological synapses. Using ion abrasion SEM, electron tomography, and superresolution light microscopy, we have analyzed the spatial architecture of cell-cell contacts and distribution of HIV virions at virological synapses formed between mature dendritic cells and T cells. We demonstrate the striking envelopment of T cells by sheet-like membrane extensions derived from mature dendritic cells, resulting in a shielded region for formation of virological synapses. Within the synapse, filopodial extensions emanating from CD4⁺ T cells make contact with HIV virions sequestered deep within a 3D network of surface-accessible compartments in the dendritic cell. Viruses are detected at the membrane surfaces of both dendritic cells and T cells, but virions are not released passively at the synapse; instead, virus transfer requires the engagement of T-cell CD4 receptors. The relative seclusion of T cells from the extracellular milieu, the burial of the site of HIV transfer, and the receptor-dependent initiation of virion transfer by T cells highlight unique aspects of cell-cell HIV transmission.