Serum anti-GM2 and anti-GalNAc-GD1a IgG antibodies are biomarkers for acute canine polyradiculoneuritis

OBJECTIVES

A previous single-country pilot study indicated serum anti-GM2 and anti-GA1 anti-glycolipid antibodies as potential biomarkers for acute canine polyradiculoneuritis. This study aims to validate these findings in a large geographically heterogenous cohort.

MATERIALS AND METHODS

Sera from 175 dogs clinically diagnosed with acute canine polyradiculoneuritis, 112 dogs with other peripheral nerve, cranial nerve or neuromuscular disorders and 226 neurologically normal dogs were screened for anti-glycolipid antibodies against 11 common glycolipid targets to determine the immunoglobulin G anti-glycolipid antibodies with the highest combined sensitivity and specificity for acute canine polyradiculoneuritis.

RESULTS

Anti-GM2 anti-glycolipid antibodies reached the highest combined sensitivity and specificity (sensitivity: 65.1%, 95% confidence interval 57.6 to 72.2%; specificity: 90.2%, 95% confidence interval 83.1 to 95.0%), followed by anti-GalNAc-GD1a anti-glycolipid antibodies (sensitivity: 61.7%, 95% confidence interval 54.1 to 68.9%; specificity: 89.3%, 95% confidence interval 82.0 to 94.3%) and these anti-glycolipid antibodies were frequently present concomitantly. Anti-GA1 anti-glycolipid antibodies were detected in both acute canine polyradiculoneuritis and control animals. Both for anti-GM2 and anti-GalNAc-GD1a anti-glycolipid antibodies, sex was found a significantly associated factor with a female to male odds ratio of 2.55 (1.27 to 5.31) and 3.00 (1.22 to 7.89), respectively. Anti-GalNAc-GD1a anti-glycolipid antibodies were more commonly observed in dogs unable to walk (OR 4.56, 1.56 to 14.87).

CLINICAL SIGNIFICANCE

Anti-GM2 and anti-GalNAc-GD1a immunoglobulin G anti-glycolipid antibodies represent serum biomarkers for acute canine polyradiculoneuritis.

Advances in anticancer radiopharmaceuticals

This review highlights recent progress in the development of anticancer radiopharmaceuticals. Molecularly targeted radiotherapy refers to the selective delivery of radionuclides that emit charged particles, such as α particles, β or Auger electrons, to cancer cells via a targeting vector. The discovery of new molecular targets through systems biology and other approaches has widened the scope for radiopharmaceutical development. Innovations in antibody engineering and humanisation, recombinant DNA technology, conjugation chemistry and, increasingly, nanotechnology have provided new approaches to the delivery of radionuclides to cancer cells. The increased availability of radioisotopes that have not traditionally been considered for therapy, such as α particle emitters, has also broadened the indications for targeted radiotherapy.

Microstructures and Properties of Ds in-Situ Composites of Nb-Ti-Si Alloys

In-situ composites based on binary Nb-Si alloys and consisting of a Nb solid solution with Nb3Si or Nb5Si3 have shown a promising combination of low temperature and high temperature mechanical properties. The environmental resistance and room temperature fracture toughness of these composites can be further enhanced by additions such as Ti, Hf, Cr, and Al. In the present study, ternary Nb-Ti-Si alloys were prepared by directional solidification to generate aligned two and three phase composites containing a Nb solid solution with Nb3Si and/or Nb5Si3. The present paper will describe microstructures, phase equilibria and fracture toughness of these composites. The improvement in the room temperature fracture toughness over binary Nb-Nb5Si3 composites is discussed.

Oxidation of Some Intermetallic Compounds and Intermetallic Matrix Composites

Oxidation resistance (1000-1400°C) was characterized for intermetallics M2Al, M3Al, M2Cr, and M5Si3 (M=Nb, Nb+Ti), and metal-toughened intermetallic composite systems. Aluminides were poorest in oxidation, and Laves phases were best. Substitution of Ti for Nb was beneficial for each intermetallic. Addition of metal to produce two-phase castings had differing effects on oxidation, depending on the metal and intermetallic. Modulus and expansion were also measured.

Analyses of eutectoid phase transformations in Nb-silicide in situ composites

Nb-silicide in situ composites have great potential for high-temperature turbine applications. Nb-silicide composites consist of a ductile Nb-based solid solution together with high-strength silicides, such as Nb5Si3 and Nb3Si. With the appropriate addition of alloying elements, such as Ti, Hf, Cr, and Al, it is possible to achieve a promising balance of room-temperature fracture toughness, high-temperature creep performance, and oxidation resistance. In Nb-silicide composites generated from metal-rich binary Nb-Si alloys, Nb3Si is unstable and experiences eutectoid decomposition to Nb and Nb5Si3. At high Ti concentrations, Nb3Si is stabilized to room temperature, and the eutectoid decomposition is suppressed. However, the effect of both Ti and Hf additions in quaternary alloys has not been investigated previously. The present article describes the discovery of a low-temperature eutectoid phase transformation during which (Nb)3Si decomposes into (Nb) and (Nb)5Si3, where the (Nb)5Si3 possesses the hP16 crystal structure, as opposed to the tI32 crystal structure observed in binary Nb5Si3. The Ti and Hf concentrations were adjusted over the ranges of 21 to 33 (at.%) and 7.5 to 33 (at.%) to understand the effect of bulk composition on the phases present and the eutectoid phase transformation.

Accurate power approximations for chi2-tests in case-control association studies of complex disease genes

A popular method for the analysis of case-control association studies is to compare the frequencies of the alleles between cases and controls by means of Pearson's chi2-statistic. Here, an approach for computing the power of this test is presented, which by computer simulation is shown to be more reliable than a previously published power approximation. Since the test based on Pearson's chi2- statistic can be anti-conservative if there is an excess of homozygotes for the susceptibility allele in the general population, it has been proposed to analyze case-control association studies by means of a trend test based on genotypes instead of alleles. We present an accurate power approximation for the trend test. The power approximations are implemented in an available computer program 'GenOdyPower', which in addition has an option to determine the empirical power of these tests by simulations.

The clinical course of new-onset atrial fibrillation after elective aortic operations

BACKGROUND

The onset of atrial fibrillation (AFIB) in the postoperative setting has been associated with increased morbidity and mortality in patients undergoing major noncardiothoracic operations. The purpose of this study was to determine the incidence, associated complications, and outcomes of AFIB after open aortic operations.

STUDY DESIGN

We studied 211 consecutive patients undergoing elective aortic operations at a single hospital during a recent 6-year period. Postoperatively all patients had continuous ECG monitoring in the ICU for a mean (+/- SD) of 6 +/- 8 days and routine cardiac enzyme determinations.

RESULTS

AFIB developed in 22 of the 211 patients (10%), a mean (+/- SD) of 2 +/- 1 days after operation, and it lasted for a mean of 4 +/- 6 days after onset. Sixteen patients spontaneously reverted to normal sinus rhythm, 3 required cardioversion (2 chemical, 1 electrical), and 3 continued in AFIB at discharge. Four of the 22 patients suffered additional cardiac complications, including antecedent MI in 3 (14%) and sustained cardiogenic shock requiring electrical cardioversion in 1. By comparison, the incidence of MI in the other 189 patients was 4% (no significant difference [NSD]). There were no deaths in the AFIB patients. Cardiac emboli developed in none of the 22 patients, and all patients had normal sinus rhythm on ECG obtained a mean of 14 +/- 10 months after discharge. Comparing the 22 patients with AFIB with the 189 patients without AFIB, there were no differences in the mean duration of ICU stay (6 +/- 4 versus 6 +/- 8 days), total length of hospital stay (10 +/- 5 versus 11 +/- 10 days), or hospital mortality (0% versus 0.5%). AFIB patients were older (71 versus 66 years, p = 0.016), but there was no difference in gender or use of beta-blockers between the two groups.

CONCLUSIONS

These data suggest that AFIB is not uncommon after aortic operations but is not associated with increased morbidity, mortality, or length of hospital stay. Although a minority of affected patients can have other cardiac complications such as MI, these complications are usually recognized before the onset of AFIB. AFIB does not affect the outcomes of aortic operations. Most patients will revert spontaneously to normal sinus rhythm and do not require longterm anticoagulation to prevent thromboembolic complications.

Fibrin sealants in surgical practice: An overview

The need to effectively manage hemostasis and tissue sealing during surgery has had a strong influence on the development of modern surgical techniques. A group of agents known as surgical tissue adhesives has been developed to promote hemostasis and tissue sealing during surgery, and these comprise both natural and synthetic agents. Fibrin sealants are the most effective tissue adhesives currently available, and they are biocompatible and biodegradable. The fibrin sealants are comprised of purified, virus-inactivated human fibrinogen, human thrombin, and sometimes added components, such as virus-inactivated human factor XIII and bovine aprotinin. These agents mimic the final steps of the physiological coagulation cascade to form a fibrin clot. The use of any plasma-derived product in the surgical setting carries a potential risk of viral transmission. In fact, it was the risk of viral transmission from fibrinogen and thrombin that halted development work on fibrin sealants in the United States. Since that time, new techniques for isolating and concentrating plasma fractions have been developed, and national and international guidelines have been introduced to ensure the safety of all plasma products. All plasma donors are carefully selected and their plasma units screened for viral contamination before processing. All plasma donations and bovine tissue used in the production of commercial fibrin sealants undergo rigorous viral reduction/elimination steps. As a result of this carefully controlled and monitored process, there have been no proven cases of viral transmission associated with the use of commercial fibrin sealant. Fibrin sealants are currently used in a number of surgical specialties, including cardiovascular surgery, thoracic surgery, neurosurgery, plastic and reconstructive surgery, and dental surgery. The use of fibrin sealants has a positive effect on surgical outcomes, such as improved time to hemostasis, reduced blood loss, and reduced complications. This review describes the development of fibrin sealants, the composition of currently available products, and their use in surgical practice.

New and potential uses of fibrin sealants as an adjunct to surgical hemostasis

Commercially prepared fibrin sealants have been available in Europe and Japan for many years. However, current formulations are exclusively two-component, liquid fibrin sealants, and delivery devices are rather rudimentary. To date, this has had the effect of limiting the number of clinical applications that make use of fibrin sealants. The recent licensing of fibrin sealants by the Food and Drug Administration in the United States has the potential to expand the use of these products in established procedures. As surgeons gain experience with fibrin sealants, it is likely that new clinical applications will be developed in a wider range of surgical specialties. The aim of this article is to explore the potential future formulations and uses of fibrin sealants and highlight a range of surgical procedures that may benefit from these products.

Global modulation of cellular transcription by human cytomegalovirus is initiated by viral glycoprotein B

Human cytomegalovirus (HCMV) infection alters the expression of many cellular genes, including IFN-stimulated genes (ISGs) [Zhu, H., Cong, J.-P., Mamtora, G., Gingeras, T. & Shenk, T. (1998) Proc. Natl. Acad. Sci. USA 95, 14470-14475]. By using high-density cDNA microarrays, we show that the HCMV-regulated gene expression profile in fibroblasts does not differ substantially from the response generated by IFN. Furthermore, we identified the specific viral component triggering this response as the envelope glycoprotein B (gB). Cells treated with gB, but not other herpesviral glycoproteins, exhibited the same transcriptional profile as HCMV-infected cells. Thus, the interaction of gB with its as yet unidentified cellular receptor is the principal mechanism by which HCMV alters cellular gene expression early during infection. These findings highlight a pioneering paradigm for the consequences of virus-receptor interactions.

The crystal structures of K(bm1) and K(bm8) reveal that subtle changes in the peptide environment impact thermostability and alloreactivity

The K(bm1) and K(bm8) natural mutants of the murine MHC class I molecule H-2K(b) were originally identified by allograft rejection. They also bind viral peptides VSV8 and SEV9 with high affinity, but their peptide complexes have substantially decreased thermostability, and the K(bm1) complexes do not elicit alloreactive T cell responses. Crystal structures of the four mutant complexes at 1.7-1.9 A resolution are similar to the corresponding wild-type K(b) structures, except in the vicinity of the mutated residues, which alter the electrostatic potential, topology, hydrogen bonding, and local water structure of the peptide binding groove. Thus, these natural K(b) mutations define the minimal perturbations in the peptide environment that alter antigen presentation to T cells and abolish alloreactivity.

The use of lepirudin for anticoagulation in patients with heparin-induced thrombocytopenia during major vascular surgery

The method of anticoagulation in patients undergoing major vascular surgery with a history of heparin-induced thrombocytopenia (HIT) is controversial. We present two cases in which a bolus only technique using recombinant hirudin (Lepirudin or Refludan) was used successfully in patients with HIT scheduled for vascular surgery.

Repair of a saccular aortic aneurysm with superficial femoral-popliteal vein in the presence of a pancreatic abscess

When one is faced with impending rupture, repair of an aortic aneurysm cannot be delayed. In the presence of coexisting intra-abdominal sepsis, traditional therapy would call for aneurysm exclusion and axillofemoral bypass grafting. Consequences of this choice of treatment include limited long-term graft patency and recurrent prosthetic infection. Autogenous deep veins from the lower extremities have demonstrated exceptional patency and resilience to infection when used to replace infected aortic grafts. We now report a case of concomitant open drainage of a pancreatic abscess and repair of a saccular abdominal aortic aneurysm using the superficial femoral-popliteal vein as a conduit.

Acute pancreatitis after abdominal vascular surgery

BACKGROUND

Retroperitoneal dissection and ischemia have been proposed as risk factors for postoperative pancreatitis. Although both are routine components of abdominal vascular operations, postoperative pancreatitis has not been adequately evaluated in vascular patients. The purpose of this study was to determine the incidence and outcomes of pancreatitis after abdominal vascular surgery.

STUDY DESIGN

We collected pre-, intra-, and postoperative data on 21 patients who developed pancreatitis after abdominal vascular operations. For comparison, we studied 21 age- and gender-matched case controls undergoing identical operations during the same period.

RESULTS

The incidence of pancreatitis among all patients undergoing abdominal vascular operations during the 6-year study period was 1.8%. Pancreatitis was diagnosed 9.8 +/- 8 days after operation and was associated with 3 or less Ranson signs in all 21 study subjects. The following outcomes data differed between the two groups: duration of npo (9 +/- 6 days for subjects versus 3.9 +/- 2 days for controls, p < 0.001) and need for parenteral nutrition (13 subjects versus no controls, p < 0.00 1). Although there was a trend towards longer hospitalization in the subjects (16 +/- 12 days versus 11 +/- 8 days, p = 0.08), there was no difference in complication rates between the two groups. Sixteen subjects (76%) had no complications. Three developed severe complications, two of whom died of causes unrelated to pancreatitis. One developed a pseudocyst that resolved spontaneously. Cholelithiasis was a causative factor in 2 subjects; no cause was established in the remaining 19. There was no difference in operative details between the two groups.

CONCLUSIONS

These data indicate that pancreatitis is a rare and self-limited complication of abdominal vascular surgery. Our findings suggest that pancreatitis is costly and inconvenient but rarely serious after abdominal vascular operations.

Watchful waiting in cases of small abdominal aortic aneurysms- appropriate for all patients?

OBJECTIVE

The purpose of this study was to determine the effect of patient compliance on a program of watchful waiting in cases of small abdominal aortic aneurysms and to document the proportion of patients who become prohibitive operative risks during follow-up.

STUDY DESIGN

A retrospective review was conducted at a regional military veterans medical center. The subjects were 101 male military veterans with abdominal aortic aneurysms measuring less than 5 cm who did not have medical contraindications to operative repair. The main outcome measures were (1) the proportion of patients who missed three scheduled radiologic tests in a row despite written notifications mailed to their homes and (2) the proportion of compliant patients who had medical illnesses and became prohibitive operative risks during follow-up.

RESULTS

During a follow-up (mean +/- SEM) of 34 +/- 2 months, 69 patients (69%) were fully compliant with the watchful waiting program and underwent a mean of 4.5 +/- 0.3 radiologic tests. There were no abdominal aortic aneurysm ruptures in this subgroup. Twenty-five patients (36%) had indications for abdominal aortic aneurysm repair, and 28 (41%) have not met the criteria for repair. Sixteen (23%) of the 69 compliant patients developed prohibitive medical risks during follow-up; eight (50%) of these 16 patients died, all of the causes unrelated to their abdominal aortic aneurysms. Thirty-two (32%) of the 101 study subjects were noncompliant with the watchful waiting program. Twenty-seven (84%) of the noncompliant patients did not keep any scheduled appointments, and five (16%) were lost after one or two examinations. Three of the noncompliant patients experienced documented abdominal aortic aneurysm rupture, and it is suspected in a fourth. Direct contact was made with 28 (88%) of these patients or their families; all acknowledged having received written notifications regarding their watchful waiting program tests and had decided not to continue with surveillance for a variety of socioeconomic reasons. Between the 69 compliant patients and the 32 noncompliant patients, there were no differences with respect to mean age (70 +/- 1 years vs 73 +/- 2 years), distance from home of record to the hospital (62 +/- 14 miles vs 73 +/- 23 miles), or abdominal aortic aneurysm size at initial detection (3.75 +/- 0.5 cm vs 3.8 +/- 0.5 cm).

CONCLUSIONS

Watchful waiting programs are imperfect and highly reliant on the motivation levels and means of the individual patients. Watchful waiting is reasonable among compliant patients with abdominal aortic aneurysms, inasmuch as fewer than half will meet the criteria for intervention within a mean of 3 years. Approximately one fourth of these patients will have medical contraindications to abdominal aortic aneurysm repair during follow-up, and many of these will die of causes other than abdominal aortic aneurysm rupture. In our experience, one third of candidates for watchful waiting programs are unable to participate and are at risk of rupture. These patients need special attention so that the reasons for their noncompliance can be determined, and they may be candidates for earlier intervention.

The consequences of a failed femoropopliteal bypass grafting: comparison of saphenous vein and PTFE grafts

OBJECTIVES

Although there are numerous reports comparing saphenous vein (SV) and polytetrafluoroethylene (PTFE) with respect to the patency rates for femoropopliteal bypass grafts, the clinical consequences of failed grafts are not as well described. This study compares the outcomes of failed SV and PTFE grafts with a specific emphasis on the degree of acute limb ischemia caused by graft occlusion.

METHODS

Over a 6-year period, 718 infrainguinal revascularization procedures were performed, of which 189 were femoropopliteal bypass grafts (SV, 108; PTFE, 81). Society for Vascular Surgery/International Society for Cardiovascular Surgery (SVS/ISCVS) standardized runoff scores were calculated from preoperative arteriograms. Clinical categories of acute limb ischemia resulting from graft occlusion were graded according to SVS/ISCVS standards (I, viable; II, threatened; III, irreversible). Primary graft patency and limb salvage rates at 48 months were calculated according to the Kaplan-Meier method.

RESULTS

Patients were well matched for age, sex, and comorbidities. Chronic critical ischemia was the operative indication in most cases (SV, 82%; PTFE, 80%; P =.85). Runoff scores and preoperative ankle-brachial index measurements were similar for the two groups (SV, 6.0 +/- 2.5 [SD] and 0.51 +/- 0.29; PTFE, 5.3 +/- 2.8 and 0.45 +/- 0.20; P =.06 and P =.12). The distal anastomosis was made below the knee in 60% of SV grafts and 16% of PTFE grafts (P <.001). Grade II ischemia was more likely to occur after occlusion of PTFE grafts (78%) than after occlusion of SV grafts (21%; P =.001). Emergency revascularization after graft occlusion was required for 28% of PTFE failures but only 3% of SV graft failures (P <.001). Primary graft patency at 48 months was 58% for SV grafts and 32% for PTFE grafts (P =.008). Limb salvage was achieved in 81% of SV grafts but only 56% of PTFE grafts (P =.019).

CONCLUSIONS

Patients undergoing femoropopliteal bypass grafting with PTFE are at greater risk of ischemic complications from graft occlusion and more frequently require emergency limb revascularization as a result of graft occlusion than patients receiving SV grafts. Graft patency and limb salvage are superior with SV in comparison with PTFE in patients undergoing femoropopliteal bypass grafting.

Effect of early maternal iron stores on placental weight and structure

BACKGROUND

Large placental size and low birthweight have been implicated as factors predicting high blood pressure in adulthood. Maternal anaemia has been suggested as a link. We investigated the interaction between maternal iron status and other factors known to influence birthweight and placental size.

METHODS

In a prospective study of 1650 low-risk, singleton, caucasian pregnancies, we related placental size and birthweight to maternal iron status, socioeconomic status, and parity. Placental morphology was assessed in 17 randomly chosen primigravid pregnancies.

FINDINGS

Parity was an important determinant of birthweight (mean standard deviation score -0.13 [SD 0.90] para 0; -0.24 [0.90] para 1; 0.32 [1.1] para 2; 0.21 [1.1] para > or = 3; p<0.0001) and placental weight (mean 655 g [SD 130]; 679 g [122]; 675 g [139]; 694 g [157], respectively; p=0.01). Cigarette smoking influenced birthweight only. Socioeconomic status had little effect after correction for parity. In addition to parity, the factors influencing placental weight were maternal height, weight, and serum ferritin concentration at booking, but not haemoglobin concentration. Serum ferritin concentrations were associated with folate intake and parity. In the placental morphology subset, serum ferritin concentration was inversely related to overall measures of peripheral villous capillarization. Haemoglobin concentration showed no such association.

INTERPRETATION

These findings show a relation between maternal anaemia and placental size and birthweight across the normal range for these measures. Low ferritin concentrations in early pregnancy were associated with increased placental vascularisation at term. The association between ferritin concentration and folate supplementation emphasises the importance of preconceptional health, particularly in women at high risk of iron deficiency.

A Fluorescence-Based High Throughput Screen for the Transporter Associated with Antigen Processing

The transporter associated with antigen processing (TAP) is essential for antigen presentation by major histocompatibility complex (MHC) class I molecules. Traditional methods used to analyze peptide transport mediated by TAP require radioactive labeling of peptides and time-consuming manipulation of Concanavalin A-Sepharose. Drug discovery research requires rapid and reliable evaluation of large number of samples for bioactivity. To meet these requirements a nonradioactive, HTS assay for peptide transport activity of TAP has been developed. The radioactive label in the traditional assays has been replaced by a fluorescent label without compromising the transport efficiency of labeled peptide or the sensitivity of the assay. The use of multiscreen filtration plates has facilitated higher throughput and eliminated the centrifugation steps used in traditional TAP assays. The HTS assay shows similar kinetic characteristics as compared to the traditional assay. The HTS assay has been adapted on a Quadratrade mark 96-320 96-channel pipetting station (Tomtec, Hamden, CT) by optimizing time course, dose response of TAP to peptides and adenosine triphosphate (ATP), signal/noise ratio, reproducibility, and reagent stability. This HTS system has been utilized to screen a multiplexed compound library with a maximum of throughput 17,600 compounds per week.

Incidental splenic injury during abdominal vascular surgery: a case-controlled analysis

BACKGROUND

The small but finite risk of postsplenectomy sepsis is generally regarded as a firm indication for splenic preservation after iatrogenic injury, especially in the young. But splenectomy may be preferable in patients who sustain splenic injuries during vascular operations because of the potential for continued bleeding associated with anticoagulation. The purpose of this study was to determine the perioperative morbidity of incidental splenectomy among patients undergoing abdominal vascular operations.

STUDY DESIGN

We studied 17 patients who underwent incidental splenectomy at the time of abdominal vascular operations. Complete data collected on each subject included preoperative and postoperative blood counts, operative indications and details, transfusion requirements, length of hospital stay, and outcomes. Using age- and gender-matched case controls undergoing identical vascular operations from the same period, we evaluated the complication rate and outcomes of patients who underwent splenectomy for iatrogenic injuries of the spleen, versus those who did not sustain splenic injuries.

RESULTS

The estimated prevalence of iatrogenic splenic injury during the study period was 0.5%. Mean operative time, estimated blood loss, and duration of mechanical ventilation tended to be greater in the splenectomy patients, but the differences did not achieve statistical significance. Splenorrhaphy was attempted in seven patients, but continued bleeding mandated spleen removal in all cases. Splenectomy patients had a higher transfusion requirement (p = 0.03) and a longer mean length of stay (p = 0.03) than controls. Compared with controls, there was a higher prevalence of infectious complications in the splenectomy patients (p = 0.015), but there was no difference in the prevalence of thromboembolic complications between groups. Two of the splenectomy patients died in the postoperative period from multisystem organ failure, and one died of a missed splenic injury.

CONCLUSIONS

These data suggest that incidental splenectomy during abdominal vascular operations is associated with increased postoperative infectious complications and prolonged hospitalization.

Immune-associated nucleotide-1 (IAN-1) is a thymic selection marker and defines a novel gene family conserved in plants

Positive selection of thymocytes is a complex and crucial event in T cell development that is characterized by cell death rescue, commitment toward the helper or cytotoxic lineage, and functional maturation of thymocytes bearing an appropriate TCR. To search for novel genes involved in this process, we compared gene expression patterns in positively selected thymocytes and their immediate progenitors in mice using the differential display technique. This approach lead to the identification of a novel gene, mIAN-1 (murine immune-associated nucleotide-1), that is switched on upon positive selection and predominantly expressed in the lymphoid system. We show that mIAN-1 encodes a 42-kDa protein sharing sequence homology with the pathogen-induced plant protein aig1 and that it defines a novel family of at least three putative GTP-binding proteins. Analysis of protein expression at various stages of thymocyte development links mIAN-1 to CD3-mediated selection events, suggesting that it represents a key player of thymocyte development and that it participates to peripheral specific immune responses. The evolutionary conservation of the IAN family provides a unique example of a plant pathogen response gene conserved in animals.

Fibrin sealant in preclinical and clinical studies

Fibrin sealant, now commercially available in the United States, is a virally inactivated preparation of highly purified human fibrinogen and human thrombin that includes aprotinin to reduce fibrinolysis. Although the product is relatively expensive, cost can be justified when the sealant is used to produce localized hemostasis in surgery in which bleeding cannot be controlled by sutures. Fibrin sealant can also be justified as an alternative to factor concentrates in patients with coagulopathies who have a localized site of bleeding. Newer formulations of fibrinogen and thrombin in a freeze-dried form applied as a bandage may be useful in immediate, on-site treatment of trauma victims in either a civilian or military setting.

TCR-Mediated internalization of peptide-MHC complexes acquired by T cells

Peptide-major histocompatibility complex protein complexes (pMHCs) on antigen-presenting cells (APCs) are central to T cell activation. Within minutes of peptide-specific T cells interacting with APCs, pMHCs on APCs formed clusters at the site of T cell contact. Thereafter, these clusters were acquired by T cells and internalized through T cell receptor-mediated endocytosis. During this process, T cells became sensitive to peptide-specific lysis by neighboring T cells (fratricide). This form of immunoregulation could explain the "exhaustion" of T cell responses that is induced by high viral loads and may serve to down-regulate immune responses.

The pharmacological and functional characteristics of the serotonin 5-HT(3A) receptor are specifically modified by a 5-HT(3B) receptor subunit

While homomers containing 5-HT(3A) subunits form functional ligand-gated serotonin (5-HT) receptors in heterologous expression systems (Jackson, M. B., and Yakel, J. L. (1995) Annu. Rev. Physiol. 57, 447-468; Lambert, J. J., Peters, J. A., and Hope, A. G. (1995) in Ligand-Voltage-Gated Ion Channels (North, R., ed) pp. 177-211, CRC Press, Inc., Boca Raton, FL), it has been proposed that native receptors may exist as heteromers (Fletcher, S., and Barnes, N. M. (1998) Trends Pharmacol. Sci. 19, 212-215). We report the cloning of a subunit 5-HT(3B) with approximately 44% amino acid identity to 5-HT(3A) that specifically modified 5-HT(3A) receptor kinetics, voltage dependence, and pharmacology. Co-expression of 5-HT(3B) with 5-HT(3A) modified the duration of 5-HT(3) receptor agonist-induced responses, linearized the current-voltage relationship, increased agonist and antagonist affinity, and reduced cooperativity between subunits. Reverse transcriptase-polymerase chain reaction in situ hybridization revealed co-localization of both 5-HT(3B) and 5-HT(3A) in a population of neurons in the amygdala, telencephalon, and entorhinal cortex. Furthermore, 5-HT(3A) and 5-HT(3B) mRNAs were expressed in spleen and intestine. Our data suggest that 5-HT(3B) might contribute to tissue-specific functional changes in 5-HT(3)-mediated signaling and/or modulation.

The progressive nature of peripheral arterial disease in young adults: a prospective analysis of white men referred to a vascular surgery service

OBJECTIVE

The onset of symptomatic peripheral arterial disease at a young age (premature PAD) has been associated with rapid progression, bypass graft failure, and amputation. This study was performed to document the incidence of these complications and to determine the risk factors for poor outcome in patients with premature PAD.

METHODS

This study was designed as a prospective longitudinal analysis, with patients who were ambulatory or hospitalized at a single vascular referral institution. The subjects were 51 white men with onset of PAD symptoms before the age of 45 years (mean age of onset, 41 +/- 0.5 years) and represented consecutive patients who were seen at the vascular surgery service during a 4-year period. Thirty of the study subjects (58%) were recruited during the first 2 years. The main outcome measures were number and type of lower extremity revascularization procedures or amputations that were necessitated during the follow-up period.

RESULTS

During a mean follow-up period of 73 +/- 6 months, 15 patients (29%) had PAD that remained stable without interventions and 15 (29%) had PAD that remained stable for a mean of 76 +/- 13 months after a single intervention. Twenty-one patients (41%) required multiple operations or major amputations. In a comparison of the 30 PAD patients whose conditions were stable with or without a single intervention with the 21 PAD patients who required multiple interventions (REDO), there were no differences in smoking, hypertension, diabetes, or dyslipidemias. The REDO group had a younger mean age at the onset of symptoms (39 +/- 1 years vs 43 +/- 2 years; P <.001). At entry, the REDO patients had a higher prevalence of infrainguinal or multilevel disease (57% vs 20%; P =.03), a lower mean ankle brachial index (0. 44 +/- 0.04 vs 0.56 +/- 0.03; P =.02), and more frequent tissue loss (24% vs 0; P =.005). The REDO patients had a higher mean lipoprotein (a) level than did the patients with stable conditions (51 +/- 11 mg/dL vs 27 +/- 5 mg/dL; P =.03), but there were no significant differences in the mean plasma homocysteine levels (19 +/- 2 micromol/L vs 16 +/- 1 micromol/L) or in the proportion of patients with hypercoagulable states (33% vs 30%). The only predictive variables that were selected with stepwise logistic regression analysis were age at onset (P <.002; odds ratio, 1.4; 95% confidence interval, 1.11 to 1.81) and ankle brachial index of less than 0.5 (P <.008; odds ratio, 6.4; 95% confidence interval, 1.5 to 27.3).

CONCLUSION

Although 60% of the white men with premature PAD who were referred to a vascular surgery service had conditions that appeared to remain stable, these data show that approximately 40% of the patients will require multiple interventions because of disease progression or bypass graft failure. Clinical indicators, not serum markers, are predictors of poor outcome in patients with premature PAD. The results of this study suggest that patients with onset of PAD before the age of 43 years who have objective evidence of advanced disease are predisposed to multiple interventions.

Hemostatic efficacy of fibrin sealant (human) on expanded poly-tetrafluoroethylene carotid patch angioplasty: a randomized clinical trial

PURPOSE

The efficacy of solvent-detergent-treated fibrin sealant (human [FSH]) for controlling anastomotic bleeding from expanded polytetrafluoroethylene (ePTFE) patch angioplasty during carotid endarterectomy was evaluated, and FSH was compared with thrombin-soaked gelatin sponge (Gelfoam; TSG).

METHODS

The study was of a randomized, open-label, single-site, single-treatment, parallel design that took place in a referral center with hospitalized patients. Forty-seven adult patients (33 men, 14 women) underwent elective carotid endarterectomy. Patients were randomized to receive either FSH (N = 24) or TSG (N = 23). FSH was obtained as an investigational new drug. FSH was applied as a liquid by means of a dual-syringe technique. Heparin anticoagulation, patch thickness, and suture type were standardized. Two different needle sizes were used (CV-6, PT-13: N = 21 [FSH: N = 10, TSG: N = 11]; CV-6, PT-9: N = 26 [FSH: N = 14, TSG: N = 13]). The FSH or TSG was applied to the ePTFE patch, and then blood flow was restored through the carotid artery. Degree of anticoagulation was assessed by anti-factor Xa activity. The time from restoration of carotid blood flow until achieving hemostasis was recorded. The blood loss from patch suture hole bleeding was measured. Completion intraoperative duplex ultrasound scanning was performed in all cases. Heparin was reversed with protamine sulfate. The primary end point was successful hemostasis within 15 minutes of restoration of carotid blood flow. The secondary end points were the amount of blood loss caused by suture line bleeding and the time to achieve hemostasis.

RESULTS

There was no difference in the number of patients with complete hemostasis at 15 minutes (TSG, 13 of 23; FSH, 12 of 24; P =.77). The measured blood loss was 99.0 +/- 119.9 (SD) mL for TSG, and 105.0 +/- 107.9 mL for FSH (P =.86). The time to hemostasis was the same for both groups (TSG, 16.5 +/- 16.5 minutes; FSH, 16.6 +/- 14.2 minutes; P =.97). Within both treatment groups, the use of larger needles (PT-13) was associated with greater blood loss (FSH, 169.7 +/- 124.2 mL; TSG, 172.7 +/- 151.5 mL) than was the use of smaller needles (PT-9; FSH, 58.8 +/- 66.3 mL; TSG, 34.1 +/- 25.6 mL; P =.036, P =.001, respectively). There were no postoperative strokes or bleeding complications in either group. No abnormalities were shown in either group by means of completion carotid duplex ultrasound scanning.

CONCLUSION

FSH was equivalent, but not superior to, TSG in achieving hemostasis during carotid endarterectomy performed with ePTFE patch angioplasty. Adhesion properties of FSH to ePTFE are possibly different than those to native tissue and warrant additional investigation.

DNA microarrays of the complex human cytomegalovirus genome: profiling kinetic class with drug sensitivity of viral gene expression

We describe, for the first time, the generation of a viral DNA chip for simultaneous expression measurements of nearly all known open reading frames (ORFs) in the largest member of the herpesvirus family, human cytomegalovirus (HCMV). In this study, an HCMV chip was fabricated and used to characterize the temporal class of viral gene expression. The viral chip is composed of microarrays of viral DNA prepared by robotic deposition of oligonucleotides on glass for ORFs in the HCMV genome. Viral gene expression was monitored by hybridization to the oligonucleotide microarrays with fluorescently labelled cDNAs prepared from mock-infected or infected human foreskin fibroblast cells. By using cycloheximide and ganciclovir to block de novo viral protein synthesis and viral DNA replication, respectively, the kinetic classes of array elements were classified. The expression profiles of known ORFs and many previously uncharacterized ORFs provided a temporal map of immediate-early (alpha), early (beta), early-late (gamma1), and late (gamma2) genes in the entire genome of HCMV. Sequence compositional analysis of the 5' noncoding DNA sequences of the temporal classes, performed by using algorithms that automatically search for defined and recurring motifs in unaligned sequences, indicated the presence of potential regulatory motifs for beta, gamma1, and gamma2 genes. In summary, these fabricated microarrays of viral DNA allow rapid and parallel analysis of gene expression at the whole viral genome level. The viral chip approach coupled with global biochemical and genetic strategies should greatly speed the functional analysis of established as well as newly discovered large viral genomes.

Cloning and functional expression of the human histamine H3 receptor

Histamine regulates neurotransmitter release in the central and peripheral nervous systems through H3 presynaptic receptors. The existence of the histamine H3 receptor was demonstrated pharmacologically 15 years ago, yet despite intensive efforts, its molecular identity has remained elusive. As part of a directed effort to discover novel G protein-coupled receptors through homology searching of expressed sequence tag databases, we identified a partial clone (GPCR97) that had significant homology to biogenic amine receptors. The GPCR97 clone was used to probe a human thalamus library, which resulted in the isolation of a full-length clone encoding a putative G protein-coupled receptor. Homology analysis showed the highest similarity to M2 muscarinic acetylcholine receptors and overall low homology to all other biogenic amine receptors. Transfection of GPCR97 into a variety of cell lines conferred an ability to inhibit forskolin-stimulated cAMP formation in response to histamine, but not to acetylcholine or any other biogenic amine. Subsequent analysis revealed a pharmacological profile practically indistinguishable from that for the histamine H3 receptor. In situ hybridization in rat brain revealed high levels of mRNA in all neuronal systems (such as the cerebral cortex, the thalamus, and the caudate nucleus) previously associated with H3 receptor function. Its widespread and abundant neuronal expression in the brain highlights the significance of histamine as a general neurotransmitter modulator. The availability of the human H3 receptor cDNA should greatly aid in the development of chemical and biological reagents, allowing a greater appreciation of the role of histamine in brain function.

Complex aortofemoral prosthetic infections: the role of autogenous superficial femoropopliteal vein reconstruction

BACKGROUND

With increasing experience, we have encountered patients with complex aortofemoral prosthetic infections in whom extra-anatomic bypass (EAB) is not an option.

HYPOTHESIS

Autogenous superficial femoropopliteal vein (SFPV) aortic reconstruction provides a limb-saving and lifesaving alternative with acceptable morbidity and mortality.

DESIGN

Retrospective review.

SETTING

University-based county, private, and Veterans Affairs hospitals.

PATIENTS

Seventeen patients with infected aortofemoral bypasses in whom conventional EAB was impossible because of infection of previously placed EAB, massive groin and/or thigh sepsis, or both.

MAIN OUTCOME MEASURES

Morbidity and mortality.

RESULTS

Multiple previous operations were common (mean, 4 per patient) and included EAB (n = 11), replacement aortofemoral bypass (n = 4), prosthetic femoropopliteal bypass (n = 7), and thoracobifemoral bypass (n = 1); all bypasses became infected. Overall, 11 patients had sepsis at the time of presentation. Of the patients with massive groin infection, 7 had extensive deep infections involving most of the proximal thighs or retroperitoneum, 4 had enterocutaneous fistulae, and 2 had necrotizing fasciitis of the lower abdomen and thigh. Polymicrobial infections were common (n = 9). Four patients (24%) died in the perioperative period, 8 (47%) suffered major complications, and 4 (24%) underwent major amputations. Mortality in this group of patients was 3 times that of all other patients undergoing autogenous SFPV aortic reconstruction for prosthetic infection (8%). Amputation rates were also increased (24% vs 6%). The mean+/-SD follow-up time is 23+/-21 months. All patients maintained patent SFPV reconstructions.

CONCLUSIONS

In the setting of complex aortofemoral prosthetic infections, autogenous SFPV aortic reconstruction is a useful option for patients in whom EAB is impossible and limb loss and/or death would be inevitable without revascularization.

Transferrin receptor is negatively modulated by the hemochromatosis protein HFE: implications for cellular iron homeostasis

Hereditary hemochromatosis is a common autosomal recessive disorder of iron metabolism. Recent demonstration of an association between transferrin receptor (TfR) and HFE, a major histocompatibility complex class I-like molecule that has been implicated to play a role in hereditary hemochromatosis, further strengthens the notion that HFE is involved in iron metabolism. Herein we show that TfR is required for and controls the assembly and the intracellular transport and surface expression of HFE. Because surface-expressed HFE and TfR remain firmly associated physically, only the fraction of TfR that is associated with HFE during biosynthesis is affected functionally. Moreover, we show that HFE binding reduces the number of functional transferrin binding sites and impairs TfR internalization, thus reducing the uptake of transferrin-bound iron. Thus, iron homeostasis is indirectly regulated by HFE, a negative modulator of TfR.

Adoptive immunotherapy prevents prostate cancer in a transgenic animal model

Cancer-related mortality can be decreased by prevention, early detection and improved therapies. Although animal models should be used to evaluate the success of cancer therapies, their usefulness is controversial. Many cancer therapies that have cured tumors in mice have not met with similar success when attempted in humans. Current animal models rely mainly on inoculating cell lines into animals, a method that does not reproduce the natural development of the tumor, both for the kinetics of induction and the anatomical site concerned. In this study, we have used an SV40 T-antigen-transgenic mouse model of prostate cancer in which the tumor spontaneously develops orthotopically with a disease progression that closely resembles the progression of human prostate cancer. We have used this model to test the suitability of adoptive cellular immunotherapy. Transfer of naive cells obtained from a T-antigen-negative congenic animal had significant but partial effects: it prevented development of malignant tumors, leaving just minor foci of residual tumor and/or hyperplasia. Adoptive transfer of memory lymphocytes specific for T-antigen, which is a prostatic self antigen in this model, prevented tumor development and progression without affecting the morphology and function of involved tissues. Treated animals were able to breed, and their survival was greatly increased. These results strongly suggest that adoptive immunotherapy should be successful in treating early stages of human prostate cancer.

Intercellular adhesion molecule-1 inhibits interleukin 4 production by naive T cells

The type of cytokines produced during T cell responses determines susceptibility or resistance to many pathogens and influences the development of autoimmunity and allergy. To define the role of individual accessory molecules in cytokine production during primary immune responses, Drosophila cell lines expressing murine major histocompatibility complex class II molecules with defined combinations of accessory molecules were used to present peptide antigen to naive T cell receptor transgenic T cells. Significantly, expression of B7.1 or B7.2 without additional accessory molecules led to very high production of interleukin (IL)-4, which contrasted with minimal IL-4 production elicited by conventional antigen presenting cells (APC). However, coexpression of ICAM-1 and B7 on Drosophila APC induced little IL-4, suggesting an inhibitory role for intercellular adhesion molecule-1 (ICAM-1). In support of this idea, stimulation of T cell receptor transgenic T cells with peptide presented by splenic APC devoid of ICAM-1 (from ICAM-1-deficient mice) led to high IL-4 production. Thus, the level of IL-4 production by naive CD4(+) T cells during typical primary responses appears to be controlled, at least in part, by T-APC interactions involving ICAM-1.

Venous morbidity after superficial femoral-popliteal vein harvest

PURPOSE

The superficial femoral-popliteal vein (SFPV) is a reliable conduit for aortoiliac, infrainguinal, and venous reconstructions. In this prospective study, we characterized the anatomic and physiologic changes in SFPV harvest limbs and their relationship to the development of late venous complications.

METHODS

Since 1990, we have studied 61 patients after harvest of 86 SFPVs at 6-month intervals with clinical examinations, lower-extremity venous duplex, and venous function tests. The CEAP system was used as a means of categorizing clinical changes.

RESULTS

Mean (+/- SEM) follow-up was 37 +/- 3 months. Less than one third of harvest limbs had edema without skin changes (C3). No patient had major chronic venous changes (C4 to C6) or venous claudication. There were no significant differences in limb measurements between harvest and non-harvest limbs, except in a subgroup of patients with unilateral harvest in which there was a small but significant (P =.046) increase in harvest limb thigh and calf circumference, compared with the opposite non-harvest limb. These clinical results were not affected by the presence or absence of an intact greater saphenous vein (GSV). Large, direct collaterals (4 to 6 mm in diameter) between the popliteal vein stump and profunda femoris vein (PFV) were seen by means of duplex ultrasonography in 29 harvest limbs (34%). The remainder appeared to have smaller, less direct collaterals to the PFV. Mild venous reflux with rapid cuff deflation was present at the popliteal or posterior tibial vein in nine of 79 harvest limbs (11%). Six of these nine limbs (67%) with reflux were clinical class C3, compared with only 19 of the 70 limbs without reflux (27%; P =.02). Ambulatory venous pressure (AVP) with exercise was significantly increased in harvest limbs (60 +/- 4.7 mm Hg), compared with non-harvest limbs (47.8 +/- 5.2 mm Hg; P =.049). The AVP recovery time of harvest limbs (14.0 +/- 1.0 seconds) was reduced, compared with non-harvest limbs (23.5 +/- 4.5 seconds; P =.02). AVPs (exercise) remained stable or decreased in six of 10 harvest limbs measured serially. Venous refill time in harvest limbs (15.1 +/- 1.1 seconds) was shortened, compared with non-harvest limbs (22.3 +/- 2. 1 seconds)(P =.002). Venous outflow obstruction measured by means of plethysmography was present in 93% of harvest limbs, compared with 36% of non-harvest limbs (P =.001).

CONCLUSION

SFPV harvest results in minimal mid-term to late-term lower-extremity venous morbidity despite outflow obstruction. The most likely mechanisms preserving clinical status include the low incidence of mild reflux, the presence of collateral venous channels, and the lack of progression in abnormal harvest limb physiology. The absence of the ipsilateral GSV does not adversely affect clinical outcome.

Physiologic responses of cross-linked hemoglobin in endotoxin-treated rats

Purified human cross-linked hemoglobin (alpha alpha Hb) as well as recombinant human hemoglobin is undergoing clinical trials in the setting of acute blood loss and perioperative hemodilution. We have previously demonstrated that in rabbits with circulating plasma Hb, such as alpha alpha Hb, infusion of endotoxin (LPS) impairs myocardial contractility which results in hypotension, tissue hypoperfusion and increased mortality. The untoward cardiovascular effects occurring after the combined infusion of LPS and alpha alpha Hb in this model are similar to those reported for other agents that inhibit nitric oxide (NO) availability. To determine if the deleterious effects of alpha alpha Hb and LPS were species specific, we performed similar studies in rats. Anesthetized Sprague-Dawley rats received LPS (4 mg/kg or 40 mg/kg) alone or in combination with alpha alpha Hb (0.7 g/kg). Mean arterial blood pressures (MAP) increased in the group that received alpha alpha Hb alone (105 +/- 8 to 120 +/- 7 mm Hg, p = 0.2) and a decrease was noted in the groups that received low dose LPS (4 mg/kg, p = 0.5) and high dose LPS (40 mg/kg, p = 0.016). MAP in rats treated with the LPS at either dose combined with alpha alpha Hb remained unchanged. Levels of urine nitrite, which was measured as a surrogate marker for plasma NO, were significantly decreased at 2 hr in groups that received the combination of alpha alpha Hb and LPS at 4 mg/kg (p = 0.022) and 40 mg/kg (p = 0.003). No significant decrease was observed in animals treated only with alpha alpha Hb (p = 0.21) or LPS (4 mg/kg; p = 0.78 and 40 mg/kg; p = 0.65). Survival was evaluated during 72 hr in animals that were infused with high dose LPS (40 mg/kg) alone or in combination with alpha alpha Hb and then allowed to recover. The survival of rats treated with LPS alone or the combination was 29% at the end of 24 hr and was 100% for rats receiving only alpha alpha Hb. The data suggest that the toxicity of alpha alpha Hb appears to be a species specific phenomenon.

A randomized trial of intraoperative autotransfusion during aortic surgery

PURPOSE

The net benefit of routine intraoperative autotransfusion (IAT) in patients undergoing elective infrarenal aortic surgery was studied.

METHODS

One hundred patients undergoing abdominal aortic aneurysm (AAA) repair (n = 50) or aortofemoral bypass (AFB) for occlusive disease (n = 50) were randomized to IAT and control groups. This experience accounted for 58% of patients undergoing aortic surgery during the 16-month study period.

RESULTS

IAT and control groups were balanced for preoperative demographics, disease (50:50 split of AFB:AAA in each group), and risk factors. There were no significant differences between patients randomized to IAT and control patients in estimated blood loss (EBL), allogeneic blood transfusion (units administered intraoperatively, postoperatively, and total), proportion of patients not receiving allogeneic blood (34% of patients randomized to IAT and 28% of control patients), postoperative hemoglobin/hematocrit levels, and complications. IAT did not reduce allogeneic blood transfusion among all patients undergoing aortic surgery nor in any subgroups that might be more likely to benefit, such as those undergoing AAA repair, those with 1000 mL or more EBL, and those receiving larger volumes of IAT-processed blood.

CONCLUSION

We could find no net benefit of IAT in patients undergoing elective, infrarenal aortic surgery.

Diagnosis and management of venous thrombosis in the surgical patient

Deep venous thrombosis (DVT) continues to be a source of major morbidity and mortality for surgical patients. The incidence of postoperative DVT is as high as 28% in some series. Risk factors include immobility, venous endothelial injury, stasis, and advanced age, all of which are highly prevalent in many populations of surgical patients. Diagnosis is generally confirmed by using duplex ultrasound to examine the legs. This modality has largely replaced contrast venography as the gold standard imaging test for DVT. Treatment begins with heparin and warfarin. Recently, low-molecular-weight heparin (LMWH) has been shown to be a suitable alternative to conventional, unfractionated heparin as the initial anticoagulant treatment of DVT. This change permits outpatient treatment of DVT in suitable patients. However, anticoagulation is contraindicated in many postoperative patients, who may then require an inferior vena caval filter. Iliofemoral venous thrombectomy should be considered when postoperative patients present with phlegmasia cerulea dolens. Long-term management of these patients focuses on measures to prevent clinical manifestations of chronic venous insufficiency.

Requirements for stimulating naive CD8+ T cells via signal 1 alone

In the absence of costimulation, TCR recognition of peptide/MHC complexes is generally considered to be nonimmunogenic. In agreement with this view, naive TCR transgenic CD8+ cells failed to respond to specific peptides presented by MHC class I (Ld) molecules bound to mouse RBC. However, peptide/Ld complexes presented by cell-sized beads or bound to plastic led to overt proliferative responses in the absence of added cytokines. Significantly, equivalent strong proliferative responses occurred when mouse RBC were fixed with glutaraldehyde before Ld coupling. The implication therefore is that the intensity of signaling via the TCR is a reflection of the mobility of the ligand being recognized; TCR signaling is weak when the ligand can move laterally on the cell membrane but strong when the ligand is immobilized.

Hemostatic efficacy of a fibrin sealant dressing in an animal model of kidney injury

OBJECTIVE

The purpose of this study is to determine the hemostatic efficacy of a fibrin sealant dressing compared with a standard collagen control dressing in an animal model of kidney injury.

METHODS

Twenty adult male Sprague-Dawley rats were administered general anesthesia and underwent partial nephrectomy with heparin anticoagulation (300 U/kg intravenous). Treatment of the cut surface of the kidney was randomized to three groups: group I, no hemostatic agent; group II, collagen dressing; and group III, fibrin sealant dressing.

RESULTS

Blood loss was significantly less in group III (3.39+/-0.63 mL) than in group I (8.64+/-2.26 mL) and group II (8.63+/-1.72 mL; p < 0.001). The percentage decrease in the mean arterial pressure was significantly less in group III (34.09+/-15.58%) than in group I (59.66+/-16.19%) and group II (60.35+/-15.66%; p=0.015).

CONCLUSION

Fibrin sealant dressings provide effective hemostasis and are superior to collagen dressings in an animal model of kidney injury. Additional development of fibrin sealant dressings for potential clinical use is warranted.