A MultiCenter Pilot Randomized Controlled Trial of Remote Ischemic Preconditioning in Major Vascular Surgery

A pilot randomized controlled trial that evaluated the effect of remote ischemic preconditioning (RIPC) on clinical outcomes following major vascular surgery was performed. Eligible patients were those scheduled to undergo open abdominal aortic aneurysm repair, endovascular aortic aneurysm repair, carotid endarterectomy, and lower limb revascularization procedures. Patients were randomized to RIPC or to control groups. The primary outcome was a composite clinical end point comprising any of cardiovascular death, myocardial infarction, new-onset arrhythmia, cardiac arrest, congestive cardiac failure, cerebrovascular accident, renal failure requiring renal replacement therapy, mesenteric ischemia, and urgent cardiac revascularization. Secondary outcomes were components of the primary outcome and myocardial injury as assessed by serum troponin values. The primary outcome occurred in 19 (19.2%) of 99 controls and 14 (14.1%) of 99 RIPC group patients ( P = .446). There were no significant differences in secondary outcomes. Our trial generated data that will guide future trials. Further trials are urgently needed.

Popliteal artery entrapment syndrome

Popliteal artery entrapment syndrome is a rare abnormality of the anatomical relationship between the popliteal artery and adjacent muscles or fibrous bands in the popliteal fossa. The following is a case report of a 19 year old female, in whom popliteal artery entrapment syndrome was diagnosed, and successfully treated surgically. A review of literature is also presented and provides details on how PAES is classified, diagnosed both clinically and radiologically, and treated surgically.

Aortic Dissections: New Perspectives and Treatment Paradigms

Aortic dissection is a complex manifestation of disease of the arterial wall. The severity and consequences of a dissection are related to the physical characteristics and anatomic location of the tear as well as the underlying patient physiology. Despite in vitro and in vivo modeling advances, our understanding of the pathophysiology has been limited to evaluations of the success and failure of various treatment modalities. The indications for intervention have historically included rupture, intractable pain or hypertension, distal ischemia and degeneration of the aortic wall causing aneurysm formation. The management decisions for patients with dissections are dependent upon the abnormal anatomy, the acuity of the patient presentation, and physiology. Despite the availability of open surgery as a therapeutic option, acute dissections with evidence of ischemia are now handled using an endovascular approach that is specifically directed at the cause of the ischemia. Endovascular treatments include the placement of a stentgraft into the proximal aorta, branch vessel stenting, uncovered stent placement in the abdominal aorta, and aortic fenestrations. Chronic dissections, in contrast, are still most frequently managed with open surgical techniques. However, a subset of patients that are not candidates for traditional surgical repair of the thoracoabdominal aorta may be managed with a combined open mesenteric revascularization with subsequent endovascular grafting of the thoracoabdominal aorta.

The social construction of anticipatory grief

As medical technology prolongs life and facilitates the early diagnosis of terminal illnesses such as AIDS, the concept of anticipatory grief requires further scrutiny. The original concept of anticipatory grief has become widely accepted. This paper, however, argues that the uncritical acceptance of this concept rests primarily on the authority of the biomedical model, which has focused analysis on the predictable symptomatology of the grief process, integrating this understanding into health care. This paper provides a critical review of the concept of anticipatory grief, highlighting conceptual shifts which are required if the concept is to be relevant to the subjective experiences of people who are confronted with life-threatening illness. The paper discusses the relevance of understanding the conceptual confusion which exists in the literature between "anticipatory grief" and "forewarning of loss". It is argued that grief may be the response to a loss of meaning, and that the psychological process of adjustment to loss requires individuals to engage in the reconstitution of purpose and meaning in their lives. Distinguishing between what is being expressed for past and present losses and what responses occur when individuals focus on various aspects of their future may shed light on some of the inconsistent and contradictory findings surrounding research on anticipatory grief.

Impaired gut barrier function in malnourished patients

The gastrointestinal tract is essential to host defence, acting as a barrier to absorption and translocation of gut antigens, including bacteria. In experimental models, protein malnutrition is permissive to gut barrier failure and endogenous infection. A clinical correlate has not been described. Intestinal morphology and barrier function to food protein antigens was studied in malnourished patients. Thirty-five individuals were evaluated, 20 malnourished patients and 15 well nourished hospital controls. Morphology was assessed from endoscopic biopsies of the second part of the duodenum, and serum immunoglobulin (Ig) G antibodies to gliadin and beta-lactoglobulin were measured. No antibody to food proteins was evident in the control group. In contrast, serum IgG antibodies to at least one antigen were present in 15 malnourished patients and to both antigens in ten (P < 0.0001 versus controls). Severely malnourished patients were more likely to have both antibodies present than those with mild or moderate malnutrition (P < 0.05). Antibody-positive malnourished patients had significantly better nutritional status than antibody-negative patients with malnutrition (P < 0.05). In no group of patients was there morphological evidence of abnormal mucosa or an immunological infiltrate. Gut barrier function is compromised in malnourished patients which suggests a mechanism that may facilitate gut-derived infection and sepsis.

Operative fixation of unstable pelvic ring injuries in polytrauma patients

Sixteen polytraumatized patients with a variety of unstable pelvic ring fractures were treated with operative fixation. We have found that an aggressive approach with adequate early stabilization of the pelvis offers many advantages over conservative management particularly in polytraumatized patients.

Product isotope effects on in vivo methanogenesis by Methanobacterium thermoautotrophicum

The hydrogen in methane produced by cultures of Methanobacterium thermoautotrophicum originates from water. In H2O/D2O mixtures, a methane product isotope effect is observed that increases rapidly as the water deuterium enrichment approaches 100%. This effect is due to the intracellular production of protons from H2, catalyzed by hydrogenase, which occurs at 12% the rate of water diffusion through the cell membrane. We estimate that water diffusion through the thick cell membrane of M. thermoautotrophicum is retarded by a factor of 10(6) over the free diffusion rate. The intracellular production of H+ suggests that either (1) hydrogenase is not directly involved in the production of a chemiosmotic proton gradient or (2) if it is involved, the proton gradient exists between the cytosol and the interior of vesicles observed in this bacterium. The intrinsic deutrium product isotope effect in methanogenesis is 1.20 +/- 0.1, comparable to anabolic deuterium product isotope effects in other autotrophs. An algebraic model incorporating the intracellular H2 to H+ flux accurately predicts the distribution of deuterated methane species at all levels of water deuterium enrichment.

Origin of hydrogen in methane produced by Methanobacterium thermoautotrophicum

The production of deuterated methane by Methanobacterium thermoautotrophicum in H2O-D2O mixtures was examined by high-resolution mass spectrometry. The hydrogen in the methane arose solely from water and not from hydrogen gas. Hydrogen gas served only as an electron source in methanogenesis. A whole-cell product isotope discrimination of 1.5 favoring hydrogen over deuterium was observed in methane production in 81 atom% deuterated water. The distribution of deuterated methane species is described by a simple model of the overall reaction.