An evidence-based resuscitation algorithm applied from the emergency room to the ICU improves survival of severe septic shock.

BACKGROUND: Septic shock is highly lethal. We recently implemented an algorithm (advanced resuscitation algorithm for septic shock, ARAS 1) with a global survival of 67%, but with a very high mortality (72%) in severe cases [norepinephrine (NE) requirements >0.3 microg/kg/min for mean arterial pressure > or =70 mmHg]. As new therapies with different levels of evidence were proposed [steroids, drotrecogin alpha, high-volume hemofiltration (HVHF)], we incorporated them according to severity (NE requirements; algorithm ARAS-2), and constructed a multidisciplinary team to manage these patients from the emergency room (ER) to the ICU. The aim of this study was to compare the outcome of severe septic shock patients under both protocols. METHODS: Adult patients with severe septic shock were enrolled consecutively and managed prospectively with ARAS-1 (1999-2001), and ARAS-2 (2002-05). ARAS-2 incorporates HVHF for intractable shock. RESULTS: Thirty-three patients were managed with each protocol, without statistical differences in baseline demographics, APACHE II (22.2 vs 23.8), SOFA (11.4 vs 12.7) and NE peak levels (0.62 vs 0.8 microg/kg/min). The 28-day mortality and epinephrine use were higher with ARAS-1 (72.7% vs 48.5%; 87.9% vs 18.2 %); and low-dose steroids (35.9% vs 72.7%), drotrecogin (0 vs 15 %) and HVHF use (3.0% vs 39.4%) were higher for ARAS-2 (P<0.05 for all). CONCLUSION: Management of severe septic shock with a multidisciplinary team and an updated protocol (according to the best current evidence), with precise entry criteria for every intervention at different stages of severity, may improve survival in these patients. Multidisciplinary management, rationalization of the use of vasoactives and rescue therapy based on HVHF instead of epinephrine may have contributed to these RESULTS: Management of severe septic shock with these kinds of algorithms is feasible and should be encouraged.

Vein adaptation to arterialization in an experimental model.

PURPOSE: The events preceding myointimal thickening in vein grafts after vascular reconstructions are not well characterized. Indeed, the injury response associated with vein graft arterialization may be different than that observed in the balloon angioplasty model. Therefore, we used a rat model to study the early cellular response after arterialization of vein grafts. METHODS: Epigastric veins were placed as femoral artery interposition grafts in 37 male Lewis rats (weight range, 350-400 g). Vein grafts and contralateral epigastric veins were harvested at different time points (6 hours, 1 day, 2 days, 3 days, 7 days, 14 days, 21 days, 30 days, and 70 days). Tissue specimens were processed for histology and immunohistochemistry with antibodies for the proliferating cell nuclear antigen (PCNA) and for different cell types. Terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) assay was used as a means of determining the presence of apoptosis. Electron microscopy was used as means of assessing the integrity of the endothelial cell surface (SEM) and confirming the presence of apoptosis (TEM). Specimens were also snap frozen in liquid nitrogen for RNA isolation and molecular analysis. RESULTS: At 1 day, endothelial denudation with platelet deposition on the surface was shown by means of SEM. Both apoptosis and necrosis of smooth muscle cells (SMCs) were present in the media, along with monocyte infiltration. Cellular proliferation and apoptosis were most intense within the first week of implantation. PCNA staining was first seen in the adventitial fibroblasts and microvessels, then in the medial SMCs at 3 days. With reverse transcriptase polymerase chain reaction, upregulation of vascular endothelial growth factor (VEGF) messenger RNA (mRNA) was noted at 1 day. Myointimal thickening progressively developed, with no apparent diminution of the luminal area as long as 70 days after implantation. By means of the analysis of the transforming growth factor beta1, mRNA showed expression during intimal thickening and accumulation of extracellular matrix. Reendothelialization was complete at 30 days. CONCLUSIONS: These observations indicate that the cellular composition in our vein graft model is similar to human stenotic explants. Endothelial denudation is observed in rat vein grafts with complete regeneration by 30 days. VEGF mRNA is upregulated at 1 day, followed by proliferation of microvessel endothelial cells in the adventitia. Cellular proliferation and apoptosis are minimal after 21 days, with progressive intimal thickening likely to be the result of matrix accumulation.

Intimal growth and neovascularization in human stenotic vein grafts.

BACKGROUND: Myointimal thickening and microvessel ingrowth are commonly observed in vein graft stenosis, which complicates a third of infrainguinal bypass procedures. But a direct correlation between these two features has not been established. Our purpose was to analyze the relationship between neovascularity and intimal thickness in human vein grafts. STUDY DESIGN: Twenty-two explant stenotic vein grafts (STVG), 8 nonstenotic arterialized vein grafts (AVG), and 20 age-matched control greater saphenous veins (CGSV) were analyzed histologically and compared morphologically by light microscopy. Digitized computer image analysis was used to measure intimal thickness and quantitate microvessel ingrowth. Immunolocalization of endothelial cells around the lumen and in microvessels was determined using antibodies to factor VIII and to endothelial nitric oxide synthase (eNOS), respectively. RESULTS: Focal areas of endothelial disruption and thrombus deposition were present in 23% (5 of 22) of stenotic vein grafts. The neointima of STVG grafts was two- and fourfold thicker than that of AVG and CGSV, respectively (p < 0.0001). Microvessels were most frequently observed in the adventitia and media of STVG and increased in number with increasing intimal thickness (p < 0.001 by ANOVA). CONCLUSIONS: A fourfold increased neointimal thickness in critically stenotic vein grafts is associated with increased medial and adventitial neovascularization. Remodeling alone with doubling of the intimal thickness in nonstenotic arterialized vein grafts does not appear to be associated with enhancement of the graft microvasculature. More specific observations using an experimental model may allow us to further define the role of angiogenesis in vein graft stenosis and to determine the therapeutic implications of such observations.

In-vivo tissue uptake and retention of Sn-117m(4+)DTPA in a human subject with metastatic bone pain and in normal mice.

Organ and tissue uptake and retention of Sn-117m(4+)DTPA were studied in a human subject treated for metastatic bone pain, and the results were compared with the biodistribution studies in five normal mice. The explanted organs from a patient who received a therapy dose of 18.6 mCi (688.2 MBq) Sn-117m(4+)DTPA and who died 47 days later were imaged with a gamma-camera, and tissue samples were counted and also autoradiographed. Bone, muscle, liver, fat, lungs, kidneys, spleen, heart and pancreas tissue samples were assayed in a well counter for radioactivity. Regions of interest were drawn over bone and major organs to calculate and quantify clearance times using three in vivo Sn-117m(4+)DTPA whole-body scintigrams acquired at 1, 24 and 168 h after injection. Five normal mice injected with the same batch of Sn-117m(4+)DTPA as used for the human subject were sacrificed at 24 h, and tissue samples were collected and assayed for radioactivity for comparison with the human data. For the human subject, whole-body retention at 47 days postinjection was 81% of the injected dose, and the rest (19%) was excreted in urine. Of the whole-body retained activity at 47 days, 82.4% was in bone, 7.8% in the muscle and 1.5% in the liver, and the rest was distributed among other tissues. Gamma-ray scintigrams and electron autoradiographs of coronal slices of the thoracolumbar vertebral body showed heterogeneous metastatic involvement with normal bone between metastatic lesions. There was nonuniform distribution of radioactivity even within a single vertebral body, indicating normal bone between metastatic lesions. Lesion-to-nonlesion ratios ranged from 3 to 5. However, the osteoid-to-marrow cavity deposition ratio, from the microautoradiographs, was 11:1. The peak uptake in the human bone was seen at 137 h with no biological clearance. Soft tissues showed peak uptake at 1 h and exhibited three compartmental clearance components. Whole-body retention in normal mice was 38.7% of the injected dose at 24 h and the rest was excreted. At 24 h postinjection, bone in mice showed 84.2% of the whole-body retention, muscle 1.7% and liver 1.4%, and the rest was distributed in other soft tissues. Percent distribution of the retained dose among bone, muscle, liver and other soft tissues is very similar between mice and a human subject. To calculate precise radiation absorbed doses from bone pain palliation radionuclides, it is necessary to take into account soft-tissue uptake and retention that may not be readily evident from routine external gamma-scintigraphy.

The histologic characteristics of primary and restenotic carotid plaque.

BACKGROUND: Although smooth muscle cell proliferation is a prominent feature of restenosis in experimental models, the role of cellular proliferation in the initiation and progression of carotid restenosis is not well documented. METHODS: Between 1985 and 1995, 35 carotid endarterectomies (CEA) in 34 patients were performed for restenosis. Patient risk factors, cerebrovascular symptoms, and operative findings were recorded. Tissue specimens from 29 of these cases and 14 original specimens from the same patient were examined by light microscopy (H&E, trichrome, elastochrome, and Alcian blue) and immunohistochemistry (alpha actin, CD 68, vWF, and proliferating nuclear cell antigen (PCNA)) in order to determine the morphologic characteristics and cellular proliferative activity of the plaque. RESULTS: Hemodynamically significant recurrent stenosis occurred in the 29 patients (69% symptomatic) between 2 months and 30 years after their initial CEAs. Eleven of 29 (38%) lesions were removed early (< 3 years). Recurrent lesions were characterized based on their components as neointimal thickening, 24% (7/29), neointimal thickening and atherosclerosis, 55% (16/29), or atherosclerotic, 21% (6/29). Nineteen of 29 (66%) plaques were complicated by mural thrombus or intraplaque hemorrhage. An inflammatory cell infiltrate consisting of macrophages and T lymphocytes was observed adjacent to areas of recurrent atherosclerosis and macrophages in regions of intimal thickening. Although infrequently present (generally 1-3% of cells) PCNA-positive cells were detected in 41% (12 of 29) of recurrent and 14% (2 of 14) of primary plaques. No PCNA-positive cells were detected in the remaining 67% (29 of 43) of specimens. There was no statistical difference in the number of PCNA-positive cells in early recurrent lesions compared to those recurring after 3 years (36% vs 44%). PCNA immunoreactivity when present was most commonly noted in macrophages associated with thrombus or atheroma rather than smooth muscle cells. CONCLUSIONS: Although evidence of cellular proliferation was observed in 40% of recurrent carotid endarterectomy lesions, the proliferation rate was low (1-3%) and unrelated to the time interval of recurrence. Proliferative activity was most pronounced in macrophages associated with intraplaque hemorrhage or atheroma. The contribution of inflammatory cells to the biologic behavior of restenotic lesions requires further investigation.

Incidence and histologic characteristics of blebs in patients with abdominal aortic aneurysms.

PURPOSE: Aortic blebs-focal outpouchings within aortic aneurysms-may contribute to their eventual rupture. In this study we determine the incidence of aortic blebs and describe their microscopic features. METHODS: Computed tomographic scans of the abdominal aorta were obtained in 188 patients with aortic diameters measuring > or = 3 cm and were independently evaluated by a radiologist. The number and location of blebs were recorded, and each was measured with calipers. Sixteen blebs, with an adjacent uninvolved aneurysmal segment of aorta, and tissue from two patients with ruptured aneurysms were examined by light microscopy and immunohistochemical analysis. Specimens from six blebs and five aneurysms were examined for alpha 1 (I) procollagen messenger RNA by in situ hybridization. RESULTS: Twenty blebs, ranging in size from 5 to 30 mm (mean, 12 +/- 7 mm), were detected in 11% (20 of 188) of computed tomographic scans. Blebs were observed in 10% (11 of 111) of patients with aortic diameters between 3.0 and 4.9 cm, 10% (6 of 61) of patients with aneurysms between 5.0 and 6.9 cm, and 19% (3 of 16) of patients with aortic diameters > or = 7 cm. Histologically, the major difference between the aneurysmal aortic wall and blebs was found in the media. In aneurysmal aortas, the media consisted of multiple layers of fragmented elastic lamellae, whereas the number of elastic tissue elements along the circumference of the blebs progressively decreased; only a few isolated fragments of elastic tissue were present at the apices. Histologic evidence of rupture was evident in two specimens. A chronic inflammatory cell infiltrate composed of T and B lymphocytes, plasma cells, and macrophages, common to both the aneurysmal and the blebs, was most prominent in the adventitia of aneurysmal tissue, but involved both the media and adventitia of the blebs. In situ hybridization demonstrated the presence of alpha 1 (I) procollagen messenger RNA in four of the five aneurysm segments that were evaluated, compared with only one of six blebs. CONCLUSIONS: Blebs were discovered in aneurysms of all sizes; their frequency appeared to be unrelated to aneurysm size. The presence of inflammatory cell infiltrates and absence of alpha 1 (I) procollagen messenger RNA in five of six blebs suggest that a local imbalance of matrix degradation and repair plays a role in the cause of these lesions. Attenuation of the aortic wall accompanying the formation of blebs may predispose these sites to rupture.

Application of ultrasound energy for intracardiac ablation of arrhythmias.

Ultrasound is a potential energy source for cardiac ablation. Small ultrasound applicators were tested for their ability to create lesions in cardiac tissue. Ultrasound applicators were designed, constructed and tested in canine cardiac tissue in degassed normal saline, and both in vitro and in vivo, lesions were produced by using transducers with frequencies of about 10 MHz. Lesion depth increased with longer duration of energy delivery from 15-60 s, and there was a linear relationship between increasing power and depth of lesions. Seven in vivo experiments in open-chest dogs were performed, and the ultrasound transducers were mounted on the tip of 7-French angiographic catheters. On the epicardium the maximum lesion depth was 9 mm. When the transducer was inserted into the left ventricle, lesions of 8.7 +/- 2.9 mm (n = 4) were produced. It is concluded that an ultrasound transducer mounted on a cardiac catheter can produce lesions that may be useful for ablation of cardiac arrhythmias.

Cellular origin and rate of endothelial cell coverage of PTFE grafts.

To determine the origin, cell type present, and rate of endothelial cell coverage of PTFE grafts, 5-cm segments of 4-mm-diameter, 60-microns PTFE grafts were implanted end-to-end bilaterally in the carotid arteries of greyhound dogs. An external jugular vein wrap was applied to the outer surface of one of the PTFE grafts; the contralateral PTFE graft, which was unwrapped, served as its control. Two dogs each were sacrificed at 3, 5, 7, 14, 21, 28, and 35 days postimplantation. Anastomotic endothelial ingrowth was analyzed using scanning electron microscopy. Microvessel ingrowth was documented in longitudinal H&E sections. Cell identity was established by immunohistochemistry with factor VIII antibody, Ulex europaes, leukocyte common antigen, and antibodies to alpha-actin, desmin, vimentin, and basic fibroblast growth factor. All grafts were patent at the time of harvest. Endothelial cell migration from the native artery adjacent to the anastomosis commenced at 7 days, extended to 5 mm beyond the proximal and distal anastomoses by 14 days and to 1.0 cm by 35 days. Endothelialization of the mid-portion of the wrapped grafts occurred via microvessel ingrowth, a process which began at 7 days. Microvessels reached the luminal surface by 28 days and an endothelial cell monolayer was established by 35 days. Wrapping the external surface of the graft with vein increased the rate of graft healing. Basic fibroblast growth factor was detectable by immunohistochemistry at the vein wrap-graft interface in the first 14 days.

Isolated ocular involvement in non-Hodgkin's lymphoma with immunocytochemical evaluation.

We report the case of a patient with isolated ocular involvement and non-Hodgkin's lymphoma (also known as reticulum cell sarcoma). Most non-Hodgkin's central nervous system lymphomas are large cell lymphomas derived from B-cells. The patient initially had iritis OD and vitreous cells OS. Eventually, rubeosis and vitritis developed OD. A systemic workup showed no extraocular lymphoma. Immunocytochemical analysis was done on the vitreous OD and detected a monoclonal B-cell population of large lymphoid cells. This case shows the frequent delay in making the diagnosis of this condition. This diagnosis must be remembered when a patient has vitreous opacities.

Atherosclerotic aneurysms of the axillary artery. A report of two cases and a review of the literature.

Atherosclerotic axillary artery aneurysms are rare. We report two cases of this entity and review the literature with respect to clinical presentation, diagnosis, operative management, and long-term outcome of these lesions.

Lipid peroxidation: a possible factor in late graft failure of coronary artery bypass grafts.

Atherosclerosis is the paramount cause of late vein graft failure after coronary artery bypass grafting. Lipid peroxidation, which may play a significant role in the initiation and progression of atherosclerosis, was examined in segments of vein grafts (n = 6) harvested at reoperation for coronary disease. These were analyzed for cholesterol, phospholipid, triglyceride, and lipid peroxides. Nonatherosclerotic vascular tissues, including coronary arteries (n = 6), saphenous veins (n = 9), and donor aortic specimens (n = 11) were analyzed for comparison. Risk factors for atherosclerosis including elevated serum cholesterol and triglycerides, smoking, and hypertension were more frequent in patients with coronary artery disease compared to organ donors. Lipid peroxides were elevated in explanted vein grafts when compared to either saphenous vein, coronary artery or donor aorta. Lipid peroxides were not significantly different in saphenous vein when compared to coronary artery, but levels in both of these tissues were greater than in donor aorta. Although increased levels of lipid peroxides in explanted veins may simply reflect morphologic changes in these grafts, the known effects of lipid peroxides on a number of biochemical events suggest that they may contribute directly to graft failure after coronary artery bypass grafting.

Resistance to infection in murine beta-thalassemia.

Clinical evidence suggests that individuals with chronic iron overload may be at increased risk of bacterial infection. We studied this question by using a unique model in which mice homozygous for a deletion in the gene encoding for the beta-major globin develop moderate anemia, splenomegaly, and tissue iron overload, a syndrome similar to beta-thalassemia in humans. Mice heterozygous for the gene deletion were phenotypically normal. Homozygous mice were significantly more susceptible to infection with Listeria monocytogenes than were heterozygous mice (P less than 0.01). This increased susceptibility was associated with a greater number of organisms in the liver and spleen than was found in heterozygous mice (P less than 0.05). However, histologic studies demonstrated similar inflammatory responses within these organs in homozygous and heterozygous mice. The increased susceptibility of homozygous mice to infection with L. monocytogenes was not seen when homozygotes were immunized with a low dose of L. monocytogenes. Although the results were not as striking as with L. monocytogenes, homozygous mice were also found to be more susceptible to infection with Salmonella typhimurium than were heterozygous mice (P less than 0.05). Splenic mononuclear cells from homozygous mice demonstrated less responsiveness in vitro to the mitogens concanavalin A and phytohemagglutinin than did those from heterozygotes (P less than 0.05). These data suggest that there is a generalized defect in innate immunity in homozygous mice which makes them more susceptible to infection by L. monocytogenes and S. typhimurium. The site of this immunological defect is not known but is most likely in the mononuclear phagocyte and may be due to tissue iron overload.

Persistent Campylobacter jejuni infections in patients infected with the human immunodeficiency virus (HIV).

We identified Campylobacter jejuni infections in four patients infected with the human immunodeficiency virus (HIV); three had persistent and severe C. jejuni infections. Multiple isolates obtained from each patient had the same biochemical and serotypic characteristics, indicating recurrent infection rather than reinfection with unrelated strains. Serum antibody responses to C. jejuni group antigens by enzyme-linked immunosorbent assay were markedly impaired in the three patients with persistent infection compared with forty-two immunocompetent C. jejuni-infected controls and with the HIV-infected patient who readily cleared the organism. One patient was bacteremic; his blood isolate was killed by normal serum but was resistant to his own serum, whereas a simultaneous stool isolate of a different serotype was sensitive. Failure of two patients to eradicate the organism and long-term administration of erythromycin therapy led to the in-vivo development of resistance to this antibiotic, which is most frequently used to treat C. jejuni infections.

Anatomic examination of human dorsal root entry zone lesions.

The anatomic delineation of radiofrequency dorsal root entry zone lesions using the Nashold thermocouple electrode is presented. The sharply delineated lesions involve a major portion of the dorsal horn of the spinal cord including Rexed's lamina V and part of VI. The extent of these lesions is appropriate, based on the currently understood mechanisms of spinal generators of chronic deafferentation pain.