Normothermic ex vivo perfusion of the limb allograft depletes donor leukocytes prior to transplantation

INTRODUCTION

The donor immune compartment plays a central role in graft rejection of the vascularised composite allograft (VCA) by contributing to 'direct presentation'. Using our limb ex vivo normothermic machine perfusion (EVNP) protocol designed for prolonged allograft preservation, this study aimed to assess whether donor leukocytes responsible for allograft rejection are mobilised from the donor compartment.

METHODS

Five genetically different pig forelimbs underwent perfusion via the brachial and radial collateral artery for 6 h after 2 h of cold storage. Oxygenated haemodilute leucocyte-deplete blood was recirculated at normothermia using an extracorporeal perfusion system. Tissue perfusion was evaluated clinically and biochemically via blood perfusate. The temporal kinetics of donor leucocyte extravasation, cytokine secretion and cell-free DNA was characterised in the circulating perfusate.

RESULTS

Flow cytometry revealed increasing populations of viable leukocytes over time, reaching 49 billion leukocytes by 6 h. T (3.0 × 10⁹ cells) and B cells (3.1 × 10⁸ cells) lymphocytes, monocytes (2.7 × 10⁹ cells), granulocytes (8.1 × 10⁹ cells), NK (6.3 × 10⁸) and γδ (8.1 × 10⁸) cells were all identified. Regulatory T cells comprised a minor population (1.6 × 10⁷ cells). There was a cumulative increase in pro-inflammatory cytokines suggesting that the donor limb has the capacity to elicit significant inflammatory responses that could contribute to leucocyte activation and diapedesis.

CONCLUSION

EVNP not only acts as a preservation tool, but could also be utilized to immunodeplete the VCA allograft prior to transplantation. This has clinical implications to mitigate acute rejection and prevent graft dysfunction and supports the future application of machine perfusion in graft preservation and immune modulation.

Iliac Telangiectatic Osteosarcoma - A Rare Presentation and Diagnostic Pitfall: A Case Report

Telangiectatic osteosarcoma is a rare variant of osteosarcoma and can be easily misdiagnosed as aneurysmal bone cyst. We report an atypical case of iliac telangiectatic osteosarcoma in a young healthy female, who presents with painful slow growing expansile lytic septate lesion in the left hemipelvis, which is initially treated as aneurysmal bone cyst. The diagnosis of aneurysmal bone cyst is made after histopathological examination of core needle biopsy. Her condition became unstable and massive bleeding is noted at the lesion site after sclerosant injection. She undergoes emergency hemipelvectomy and eventually the biopsy turns up to be telangiectatic osteosarcoma. Our case highlights that core needle biopsy is not useful in making diagnosis for iliac telangiectatic carcinoma. Hence, an open biopsy should be carried out in our case. This case also emphasises on careful evaluation for malignancy which is mandatory because bleeding from pelvis after an unsuitable treatment can be grave, to the extent that major amputation hemipelvectomy is an option. Even though telangiectatic osteosarcoma has the same prognosis and treatment with conventional osteosarcoma, the outcome of delayed treatment for telangiectatic osteosarcoma is not good due to the dilemma in establishing an early correct diagnosis.

Neuroimaging Advances in Deep Brain Stimulation: Review of Indications, Anatomy, and Brain Connectomics

Deep brain stimulation is an established therapy for multiple brain disorders, with rapidly expanding potential indications. Neuroimaging has advanced the field of deep brain stimulation through improvements in delineation of anatomy, and, more recently, application of brain connectomics. Older lesion-derived, localizationist theories of these conditions have evolved to newer, network-based "circuitopathies," aided by the ability to directly assess these brain circuits in vivo through the use of advanced neuroimaging techniques, such as diffusion tractography and fMRI. In this review, we use a combination of ultra-high-field MR imaging and diffusion tractography to highlight relevant anatomy for the currently approved indications for deep brain stimulation in the United States: essential tremor, Parkinson disease, drug-resistant epilepsy, dystonia, and obsessive-compulsive disorder. We also review the literature regarding the use of fMRI and diffusion tractography in understanding the role of deep brain stimulation in these disorders, as well as their potential use in both surgical targeting and device programming.

Decentralization of care for adults with congenital heart disease in the United States: a geographic analysis of outpatient surgery

Background

Guidelines recommend that adults with congenital heart disease (CHD) undergo noncardiac surgery in regionalized centers of expertise, but no studies have assessed whether this occurs in the United States. We hypothesized that adults with CHD are less likely than children to receive care at specialized CHD centers.

Methods

Using a comprehensive state ambulatory surgical registry (California Ambulatory Surgery Database, 2005–2011), we calculated the proportion of adult and pediatric patients with CHD who had surgery at a CHD center, distance to the nearest CHD center, and distance to the facility where surgery was performed.

Results

Patients with CHD accounted for a larger proportion of the pediatric population (n = 11,254, 1.0%) than the adult population (n = 10,547, 0.07%). Only 2,741 (26.0%) adults with CHD had surgery in a CHD center compared to 6,403 (56.9%) children (p<0.0001). Adult CHD patients who had surgery at a non-specialty center (11.9±15.4 miles away) lived farther from the nearest CHD center (37.9±43.0 miles) than adult CHD patients who had surgery at a CHD center (23.2±28.4 miles; p<0.0001). Pediatric CHD patients who had surgery at a non-specialty center (18.0±20.7 miles away) lived farther from the nearest CHD center (35.7±45.2 miles) than pediatric CHD patients who had surgery at a CHD center (22.4±26.0 miles; p<0.0001).

Conclusions

Unlike children with CHD, most adults with CHD (74%) do not have outpatient surgery at a CHD center. For both adults and children with CHD, greater distance from a CHD center is associated with having surgery at a non-specialty center. These results have significant public health implications in that they suggest a failing to achieve adequate regional access to specialized ACHD care. Further studies will be required to evaluate potential strategies to more reliably direct this vulnerable population to centers of expertise.

Temporal changes in survival after cardiac surgery are associated with the thirty-day mortality benchmark

OBJECTIVE

To assess the hypothesis that postoperative survival exhibits heterogeneity associated with the timing of quality metrics.

DATA SOURCES

Retrospective observational study using the Nationwide Inpatient Sample from 2005 through 2009.

STUDY DESIGN

Survival analysis was performed on all admission records with a procedure code for major cardiac surgery (n = 595,089). The day-by-day hazard function for all-cause in-hospital mortality at 1-day intervals was analyzed using joinpoint regression (a data-driven method of testing for changes in hazard).

DATA EXTRACTION METHODS

A comprehensive analysis of a publicly available national administrative database was performed.

PRINCIPAL FINDINGS

Statistically significant shifts in the pattern of postoperative mortality occurred at day 6 (95 percent CI = day 5-8) and day 30 (95 percent CI = day 20-35).

CONCLUSIONS

While the shift at day 6 plausibly can be attributed to the separation between routine recovery and a complicated postoperative course, the abrupt increase in mortality at day 30 has no clear organic etiology. This analysis raises the possibility that this observed shift may be related to clinician behavior because of the use of 30-day mortality as a quality metric, but further studies will be required to establish causality.

Perioperative Morbidity and Mortality after Noncardiac Surgery in Young Adults with Congenital or Early Acquired Heart Disease: A Retrospective Cohort Analysis of the National Surgical Quality Improvement Program Database

An increasing number of patients with congenital heart disease survive to adulthood. Expert opinion suggests that noncardiac surgery is a high-risk event, but few data describe perioperative outcomes in this population. Using the National Surgical Quality Improvement Program database, we identified a cohort of patients aged 18 to 39 years with prior heart surgery who underwent noncardiac surgery between 2005 and 2010. A comparison cohort with no prior cardiovascular surgery was matched on age, sex, race/ethnicity, operation year, American Society of Anesthesiologists physical status, and Current Procedural Terminology code. A study cohort consisting of 1191 patients was compared with a cohort of 5127 patients. Baseline dyspnea, inpatient status at the time of surgery, and a prior operation within 30 days were more common in the study cohort. Postoperative outcomes were less favorable in the study cohort. Observed rates of death, peri-operative cardiac arrest, myocardial infarction, stroke, respiratory complications, renal failure, sepsis, venous thromboembolism, perioperative transfusion, and reoperation were significantly higher in the study cohort ( P < 0.01 for all). Mean postoperative length of stay was greater in the study cohort (5.8 vs 3.6 days, P < 0.01). Compared with a matched control cohort, young adult patients with a history of prior cardiac surgery experienced significantly greater perioperative morbidity and mortality after noncardiac surgery. A history of prior cardiac surgery represents a marker of substantial perioperative risk in this young population that is not accounted for by the matched variables. These results suggest that adult patients with congenital heart disease are at risk for adverse outcomes and support the need for further registry-based investigations.

Perioperative morbidity and mortality after noncardiac surgery in young adults with congenital or early acquired heart disease: a retrospective cohort analysis of the National Surgical Quality Improvement Program database

An increasing number of patients with congenital heart disease survive to adulthood. Expert opinion suggests that noncardiac surgery is a high-risk event, but few data describe perioperative outcomes in this population. Using the National Surgical Quality Improvement Program database, we identified a cohort of patients aged 18 to 39 years with prior heart surgery who underwent noncardiac surgery between 2005 and 2010. A comparison cohort with no prior cardiovascular surgery was matched on age, sex, race/ethnicity, operation year, American Society of Anesthesiologists physical status, and Current Procedural Terminology code. A study cohort consisting of 1191 patients was compared with a cohort of 5127 patients. Baseline dyspnea, inpatient status at the time of surgery, and a prior operation within 30 days were more common in the study cohort. Postoperative outcomes were less favorable in the study cohort. Observed rates of death, perioperative cardiac arrest, myocardial infarction, stroke, respiratory complications, renal failure, sepsis, venous thromboembolism, perioperative transfusion, and reoperation were significantly higher in the study cohort (P < 0.01 for all). Mean postoperative length of stay was greater in the study cohort (5.8 vs 3.6 days, P < 0.01). Compared with a matched control cohort, young adult patients with a history of prior cardiac surgery experienced significantly greater perioperative morbidity and mortality after noncardiac surgery. A history of prior cardiac surgery represents a marker of substantial perioperative risk in this young population that is not accounted for by the matched variables. These results suggest that adult patients with congenital heart disease are at risk for adverse outcomes and support the need for further registry-based investigations.

Perioperative morbidity and mortality of cardiothoracic surgery in patients with a do-not-resuscitate order

Background. Do-not-resuscitate (DNR) orders are often active in patients with multiple comorbidities and a short natural life expectancy, but limited information exists as to how often these patients undergo high-risk operations and of the perioperative outcomes in this population.

Methods. Using comprehensive inpatient administrative data from the Public Discharge Data file (years 2005 through 2010) of the California Office of Statewide Health Planning and Development, which includes a dedicated variable recording DNR status, we identified cohorts of DNR patients who underwent major cardiac or thoracic operations and compared themto age- and procedure-matched comparison cohorts. The primary study outcome was in-hospital mortality.

Results. DNR status was not uncommon in cardiac (n = 2,678, 1.1% of all admissions for cardiac surgery, age 71.6 ± 15.9 years) and thoracic (n = 3,129, 3.7% of all admissions for thoracic surgery, age 73.8 ± 13.6 years) surgical patient populations. Relative to controls, patients who were DNR experienced significantly greater inhospital mortality after cardiac (37.5% vs. 11.2%, p < 0.0001 and thoracic (25.4% vs. 6.4%) operations. DNR status remained an independent predictor of in-hospital mortality onmultivariate analysis after adjustment for baseline and comorbid conditions in both the cardiac (OR 4.78, 95% confidence interval 4.21–5.41, p < 0.0001) and thoracic (OR 6.11, 95% confidence interval 5.37–6.94, p < 0.0001) cohorts.

Conclusions. DNR status is associated with worse outcomes of cardiothoracic surgery even when controlling for age, race, insurance status, and serious comorbid disease. DNR status appears to be a marker of substantial perioperative risk, and may warrant substantial consideration when framing discussions of surgical risk and benefit, resource utilization, and biomedical ethics surrounding end-of-life care.

Heart transplantation with or without prior mechanical circulatory support in adults with congenital heart disease

OBJECTIVES

Recent analyses establish that heart transplantation is increasing among adults with congenital heart disease (ACHD), but the effects of pretransplant mechanical circulatory support (MCS) on perioperative and post-transplant outcomes have not been examined in the ACHD population.

METHODS

Scientific Registry of Transplant Recipients data on all adult heart transplants from September 1987 to September 2012 (n = 47 160) were classified based on primary diagnosis codes as CHD or non-CHD and MCS or non-MCS. Demographic, procedural, outcome and survival variables were compared between MCS and non-MCS ACHD patient groups.

RESULTS

MCS was used in 83 (6.8%) ACHD patients compared with 8625 (18.8%) patients without CHD (P < 0.001). MCS as a fraction of ACHD transplants increased over time (P = 0.002). MCS patients spent more time on the wait list, had a higher baseline serum creatinine and were more likely to be male, status 1A, hospitalized, in the ICU and/or on a ventilator prior to transplant. However, MCS patients experienced equivalent short-term survival (30-day mortality = 10.8% in MCS vs 13.5% in non-MCS, P = 0.62) and overall survival by Kaplan-Meier analysis (P = 0.57). MCS patients had a longer post-transplant length of stay and were more likely to be transfused, but otherwise had no significant differences in adverse outcomes.

CONCLUSIONS

MCS is less commonly used in adult CHD patients compared with all patients undergoing heart transplant, but has been increasing over time. Within the ACHD population, patients with MCS have a higher risk profile, but except for increased transfusion rate and longer length of stay, do not experience less favourable post-transplant outcomes.

Investigation of 2D and 3D electrospun scaffolds intended for tendon repair

Two-dimensional (2D) electrospun fibre mats have been investigated as fibrous sheets intended as biomaterials scaffolds for tissue repair. It is recognised that tissues are three-dimensional (3D) structures and that optimisation of the fabrication process should include both 2D and 3D scaffolds. Understanding the relative merits of the architecture of 2D and 3D scaffolds for tendon repair is required. This study investigated three different electrospun scaffolds based on poly(ε-caprolactone) fibres intended for repair of injured tendons, referred to as; 2D random sheet, 2D aligned sheet and 3D bundles. 2D aligned fibres and 3D bundles mimicked the parallel arrangement of collagen fibres in natural tendon and 3D bundles further replicated the tertiary layer of a tendon's hierarchical configuration. 3D bundles demonstrated greatest tensile properties, being significantly stronger and stiffer than 2D aligned and 2D random fibres. All scaffolds supported adhesion and proliferation of tendon fibroblasts. Furthermore, 2D aligned sheets and 3D bundles allowed guidance of the cells into a parallel, longitudinal arrangement, which is similar to tendon cells in the native tissue. With their superior physical properties and ability to better replicate tendon tissue, the 3D electrospun scaffolds warrant greater investigation as synthetic grafts in tendon repair.

Inventory management

A critical aspect of blood transfusion is the timely provision of high quality blood products. This task remains a significant challenge for many blood services and blood systems reflecting the difficulty of balancing the recruitment of sufficient donors, the optimal utilization of the donor's gift, the increasing safety related restrictions on blood donation, a growing menu of specialized blood products and an ever-growing imperative to increase the efficiency of blood product provision from a cost perspective. As our industry now faces questions about our standard practices including whether or not the age of blood has a negative impact on recipients, it is timely to take a look at our collective inventory management practices. This International Forum represents an effort to get a snap shot of inventory management practices around the world, and to understand the range of different products provided for patients. In addition to sharing current inventory management practices, this Forum is intended to foster an exchange of ideas around where we see our field moving with respect to various issues including specialty products, new technologies, and reducing recipient risk from blood transfusion products.

Estimating selection pressures on HIV-1 using phylogenetic likelihood models

Human immunodeficiency virus (HIV-1) can rapidly evolve due to selection pressures exerted by HIV-specific immune responses, antiviral agents, and to allow the virus to establish infection in different compartments in the body. Statistical models applied to HIV-1 sequence data can help to elucidate the nature of these selection pressures through comparisons of non-synonymous (or amino acid changing) and synonymous (or amino acid preserving) substitution rates. These models also need to take into account the non-independence of sequences due to their shared evolutionary history. We review how we have developed these methods and have applied them to characterize the evolution of HIV-1 in vivo. To illustrate our methods, we present an analysis of compartment-specific evolution of HIV-1 env in blood and cerebrospinal fluid and of site-to-site variation in the gag gene of subtype C HIV-1.

Genetic composition of human immunodeficiency virus type 1 in cerebrospinal fluid and blood without treatment and during failing antiretroviral therapy

Human immunodeficiency virus (HIV) infection of the central nervous system (CNS) is a significant cause of morbidity. The requirements for HIV adaptation to the CNS for neuropathogenesis and the value of CSF virus as a surrogate for virus activity in brain parenchyma are not well established. We studied 18 HIV-infected subjects, most with advanced immunodeficiency and some neurocognitive impairment but none with evidence of opportunistic infection or malignancy of the CNS. Clonal sequences of C2-V3 env and population sequences of pol from HIV RNA in cerebrospinal fluid (CSF) and plasma were correlated with clinical and virologic variables. Most (14 of 18) subjects had partitioning of C2-V3 sequences according to compartment, and 9 of 13 subjects with drug resistance exhibited discordant resistance patterns between the two compartments. Regression analyses identified three to seven positions in C2-V3 that discriminated CSF from plasma HIV. The presence of compartmental differences at one or more of the identified positions in C2-V3 was highly associated with the presence of discordant resistance (P = 0.007), reflecting the autonomous replication of HIV and the independent evolution of drug resistance in the CNS. Discordance of resistance was associated with severity of neurocognitive deficits (P = 0.07), while low nadir CD4 counts were linked both to the severity of neurocognitive deficits and to discordant resistance patterns (P = 0.05 and 0.09, respectively). These observations support the study of CSF HIV as an accessible surrogate for HIV virions in the brain, confirm the high frequency of discordant resistance in subjects with advanced disease in the absence of opportunistic infection or malignancy of the CNS, and begin to identify genetic patterns in HIV env associated with adaptation to the CNS.

Heterogeneous clearance rates of long-lived lymphocytes infected with HIV: intrinsic stability predicts lifelong persistence

Viral replication and latently infected cellular reservoirs persist in HIV-infected patients achieving undetectable plasma virus levels with potent antiretroviral therapy. We exploited a predictable drug resistance mutation in the HIV reverse transcriptase to label and track cells infected during defined intervals of treatment and to identify cells replenished by ongoing replication. Decay rates of subsets of latently HIV-infected cells paradoxically decreased with time since establishment, reflecting heterogeneous lymphocyte activation and clearance. Residual low-level replication can replenish cellular reservoirs; however, it does not account for prolonged clearance rates in patients without detectable viremia. In patients receiving potent antiretroviral therapy, the latent pool has a heterogeneous and dynamic composition that comprises a progressively increasing proportion of stable lymphocytes. Eradication will not be achieved with complete inhibition of viral replication alone.

Spatiotemporal Dynamics of HIV Propagation

Although viral propagation is a localized process, mathematical models of viral replication kinetics have been limited to systems of ordinary differential equations describing spatially averaged behavior. In this paper, we introduce a cellular automaton model of viral propagation based on the known biophysical properties of HIV. In particular, we include the competition between viral lability and Brownian motion. The model predicts three testable effects not present in previous descriptions. First, we find a profound dependence of viral infectivity on cell concentration; virion instability decreases infectivity more than 100-fold under typical experimental conditions, resulting in misleading estimates of the number of infectious particles. Second, we find that, in a large parameter regime, infection extinguishes itself due to insufficient target cell replenishment. Finally, we find that propagation is limited by viral stability at low cell density and by geometry at high cell density. The geometry-limited regime can be modulated by downregulation of CD4. These different properties are analysed quantitatively and compared with previous experimental results.

Analysis of early failure of tunneled hemodialysis catheters

OBJECTIVE

Tunneled hemodialysis catheters are often placed by the interventional radiology service using sonographic guidance and fluoroscopy for safe and optimal placement. The aim of this study was to determine the causes of early failure (<or=7 days) of these catheters in our practice.

SUBJECTS AND METHODS

Data were prospectively collected for 639 radiologically placed tunneled hemodialysis catheters. The reason for catheter removal was recorded in each case. Tips of removed catheters were routinely sent for microbial culture.

RESULTS

Fifty-two (8.1%) of 639 catheters were removed within 7 days of insertion. Six (0.9%) of these had completed their purpose and had not failed; these were not included in the study. Of the 46 catheters having early failure, six (0.9%) were clotted and 12 (1.9%) were suspected of being infected, only three of which had a proven catheter-related infection. Twenty-eight catheters (4.4%) were removed for other reasons. In this group, the most common reasons were poor tip position (n = 9) and catheter replacement over a guidewire into a preexisting fibrin sheath (n = 8). Only two failed because of poor tip orientation. Other reasons for failure were kinked or pinched catheters (n = 4) and bleeding (n = 3), including one exsanguination, and two unknown reasons.

CONCLUSION

By paying careful attention to catheter tip position, searching diligently for the presence of a fibrin sheath when catheter exchanges are made over a wire, and better investigating presumed catheter infection, we could reduce the early failure rate by more than half, from 46 cases to 20 cases (nine cases of suspected infection were in fact not infected).

Simplified serum- and steroid-free culture conditions for high-throughput viability analysis of primary cultures of cerebellar granule neurons

A serum- and steroid-free primary culture system was developed for the maintenance and automated analysis of cerebellar granule cell viability. Conventional poly-lysine coated 96-well tissue culture plates serve as a platform for growth, experimental manipulation and subsequent automated analysis of these primary cultured neurons. Cerebellar granule neurons were seeded at densities ranging from 2 x 10(4) to 1.25 x 10(6) cells/cm(2) and maintained in serum- and steroid-free culture conditions for 7 days. Viability was subsequently determined by the reduction of [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS), and the degree of cell death occurring over that period was determined by the release of lactate dehydrogenase (LDH). At appropriate cell densities, the results of the MTS reduction and LDH release assays were directly proportional to the initial number of cerebellar granule cells plated. Those results indicate that an initial cell density of 0.5 - 1.0 x 10(5) cells per well (0.32 cm(2)) was appropriate for simultaneous analysis with the MTS reduction and LDH release assays. Both assays were then used to demonstrate the utility of this model system for analysis of tert-butyl-hydroperoxide and hydrogen peroxide induced oxidative stress. Additionally, the MTS reduction assay was used to demonstrate that the NMDA-receptor selective antagonist MK-801 was neuroprotective against glutamate-mediated excitotoxicity. This study defines a powerful and flexible primary culture system for cerebellar neurons that is useful for high-throughput analysis of factors that influence neuronal viability.

Prevalence and predictive value of intermittent viremia with combination hiv therapy

CONTEXT

In HIV-infected patients having virologic suppression (plasma HIV RNA <50 copies/mL) with antiretroviral therapy, intermittent episodes of low-level viremia have been correlated with slower decay rates of latently infected cells and increased levels of viral evolution, but the clinical significance of these episodes is unknown.

OBJECTIVE

To determine if HIV-infected patients with intermittent viremia have a higher risk of virologic failure (confirmed HIV RNA >200 copies/mL).

DESIGN AND SETTING

Retrospective analysis of subjects in well-characterized cohorts, the AIDS Clinical Trials Group (ACTG) 343 trial of induction-maintenance therapy (August 1997 to November 1998) and the Merck 035 trial (ongoing since March 1995).

PATIENTS

Two hundred forty-one ACTG 343 patients, of whom 101 received triple-drug therapy throughout the study, and a small group of 13 patients from Merck 035 having virologic suppression after 6 months of indinavir-zidovudine-lamivudine.

MAIN OUTCOME MEASURES

Association of intermittent viremia (plasma HIV RNA >50 copies/mL with a subsequent measure <50 copies/mL) with virologic failure (2 consecutive plasma HIV RNA measures >200 copies/mL) in both study groups; evidence of drug resistance in 7 patients from the small (n = 13) study group with long-term follow-up.

RESULTS

Intermittent viremia occurred in 96 (40%) of the 241 ACTG 343 patients of whom 32 (13%) had 2 consecutive HIV RNA values >50 copies/mL during the median 84 weeks of observation (median duration of observation after first intermittent viremia episode was 46 weeks). Of the 101 individuals receiving triple-drug therapy throughout, 29% had intermittent viremia; the proportion of episodes occurring during the maintenance period was 64% for the entire cohort and 68% for the group not receiving triple-drug therapy throughout vs 55% for those who did (P =.25). Intermittent viremia did not predict virologic failure: 10 (10.4%) of 96 patients with and 20 (13.8%) of 145 patients without intermittent viremia had virologic failure (relative risk, 0.76; 95% confidence interval [CI], 0.29-1.72). In a Cox proportional hazards model, the risk for virologic failure was not significantly greater in the ACTG 343 patients with intermittent viremia (hazard ratio, 1.28; 95% CI, 0.59-2.79). Median viral load in 10 ACTG 343 patients assessed between 24 and 60 weeks of therapy using an ultrasensitive 2.5-copies/mL detection level assay was 23 copies/mL in those with intermittent viremia vs <2.5 copies/mL in those without (P =.15). Intermittent viremia occurred in 6 of 13 patients from the small study group assessed after 76 to 260 weeks of therapy (using the 2.5-copies/mL detection level assay) and was associated with a higher steady state of viral replication (P =.03), but not virologic failure over 4.5 years of observation. Viral DNA sequences from 7 patients did not show evolution of drug resistance.

CONCLUSIONS

Intermittent viremia occurred frequently and was associated with higher levels of replication (Merck 035), but was not associated with virologic failure in patients receiving initial combination therapy of indinavir-zidovudine-lamivudine (ACTG 343 and Merck 035). In this population, treatment changes may not be necessary to maintain long-term virologic suppression with low-level or intermittent viremia.

Adjuncts to local anesthesia: separating fact from fiction

Adjunctive local anesthetic techniques and their armamentaria, such as intraosseous injection, computer-controlled delivery systems, periodontal ligament injection and needleless jet injection, have been proposed to hold particular advantages over conventional means of achieving local anesthesia. This article describes the use of each technique and proprietary armamentarium and reviews the literature appraising their use.

Stiff, and sticky in the right places: the dramatic influence of preorganizing guest binding sites on the hydrogen bond-directed assembly of rotaxanes

Structural rigidity and the preorganization of thread binding sites are shown to have a major influence on template efficiency in the synthesis of hydrogen bond-assembled rotaxanes. Preorganization is so effective, in fact, that with good hydrogen bond acceptors (amides) a "world record" yield of 97% for a [2]rotaxane is obtained. The truly remarkable feature of this efficient template, however, is that it allows even poor hydrogen bond acceptors (esters) to be used to prepare hydrogen bond-assembled rotaxanes, despite the presence of competing hydrogen bonding groups (anions) which bind the key intermediates at least 10000x more strongly than single, unorganized, ester groups! The structures of the rotaxanes are established unambiguously in solution by (1)H NMR spectroscopy and in the solid state by X-ray crystallography. As a series they provide unique experimental information regarding the nature of amide-ester hydrogen bonding interactions; in particular they suggest that in CDCl(3), amide-ester NH...O=C hydrogen bonds are approximately 1 kcal mol(-)(1) weaker than the corresponding amide-amide interactions.

Evidence for positive selection driving the evolution of HIV-1 env under potent antiviral therapy

In HIV-infected individuals treated with potent antiretroviral therapy, viable virus can be isolated from latently infected cells several years into therapy, due to the long life of these cells, ongoing replication replenishing this population, or both. We have analysed the V3 region of the HIV-1 env gene isolated from six patients who have undergone 2 years of potent antiretroviral therapy without frank failure of viral suppression. We show that in two (and possibly three) patients, the sequence changes between baseline virus and virus isolated from infected cells persisting 2 years into infection result from positive selection driving adaptive evolution, occurring either prior to or during therapy. Our analyses suggest low-level replication despite absence of drug resistance due to drug sanctuary sites, or to low-level ongoing replication in the presence of alterations in the selective environment during therapy, perhaps due to a decline in HIV-specific immune responsiveness or changes in target cell pools. In one patient, genetic divergence between baseline plasma and infected cells isolated during therapy may reflect the long half-life of some of these persistent cell populations and the divergence of viral subpopulations that occurred prior to therapy.

Residual human immunodeficiency virus (HIV) Type 1 RNA and DNA in lymph nodes and HIV RNA in genital secretions and in cerebrospinal fluid after suppression of viremia for 2 years

Residual viral replication persists in a significant proportion of human immunodeficiency virus (HIV)-infected patients receiving potent antiretroviral therapy. To determine the source of this virus, levels of HIV RNA and DNA from lymphoid tissues and levels of viral RNA in serum, cerebrospinal fluid (CSF), and genital secretions in 28 patients treated for < or =2.5 years with indinavir, zidovudine, and lamivudine were examined. Both HIV RNA and DNA remained detectable in all lymph nodes. In contrast, HIV RNA was not detected in 20 of 23 genital secretions or in any of 13 CSF samples after 2 years of treatment. HIV envelope sequence data from plasma and lymph nodes from 4 patients demonstrated sequence divergence, which suggests varying degrees of residual viral replication in 3 and absence in 1 patient. In patients receiving potent antiretroviral therapy, the greatest virus burden may continue to be in lymphoid tissues rather than in central nervous system or genitourinary compartments.

Local anesthesia does not block mustard-oil-induced temporomandibular inflammation

Temporomandibular joint (TMJ) disorders and rheumatoid arthritis are two conditions in which neurogenic mechanisms may play a critical role. We investigated the neurogenic contribution underlying acute TMJ inflammation by evaluating effects of local anesthetic blockade of afferent innervation on the development of mustard oil (MO)-induced edema in the rat TMJ area. Groups of eight adult male Sprague-Dawley rats were anesthetized by intraperitoneal alpha-chloralose and urethane. A saline injection into the right TMJ followed by MO (1% to 60%) 6 min later elicited dose-dependent edema development (P < 0.05, repeated measures analysis of variance). Lidocaine (5%) or bupivacaine (0.5%) followed by MO (1% or 40%) did not produce edema development different from saline controls (P > 0.05, repeated measures analysis of variance). The failure of local anesthetic blockade to prevent MO-induced edema is not consistent with MO acting through a neurogenic mechanism, as traditionally perceived.

IMPLICATIONS

Inflammation found in temporomandibular disorders and rheumatoid arthritis may result from mediators released by pain-sensing neurons. Local anesthesia failed to block simulated neurogenic temporomandibular inflammation in a rat model, suggesting that functional neuronal input may not be necessary for the promotion of inflammation.

Productive infection of T cells in lymphoid tissues during primary and early human immunodeficiency virus infection

Current models suggest that during human immunodeficiency virus type 1 (HIV-1) transmission virions are selected that use the CCR5 chemokine receptor on macrophages and/or dendritic cells. A gradual evolution to CXCR4 chemokine receptor use causes a shift in the proportion of productively infected cells to the CD4 cell population. Productively infected cells during acute and early infection in lymphoid tissue were assessed, as well as the impact of productive infection on the T cell population in 21 persons who had biopsies performed on days 2-280 after symptoms of acute HIV-1 seroconversion. Even in the earliest stages of infection, most productively infected cells were T lymphocytes. There were sufficient infected cells in lymphoid tissue (LT) to account for virus production and virus load in plasma. Despite the relatively high frequency of productively infected cells in LT, the impact on the size of the T cell population in LT at this stage was minor.

Estrogen receptor beta immunoreactivity in differentiating cells of the developing rat cerebellum

Estrogen receptors (ER) play a significant role in the development of some regions of the mammalian brain. Recently, ER-beta (ERbeta) mRNA and protein were shown to be expressed in the rat cerebellum. In the present study, the ontogeny of ERbeta protein expression was examined in the rat cerebellum during postnatal development. Western blot analysis indicated that a single ERbeta-like immunoreactive species of approximately 55 kDa was present in protein lysates prepared from the cerebella of female and male Sprague-Dawley rat pups. Immunocytochemical analysis of cerebellar sections from the midline vermis revealed that during development, the expression of ERbeta varied with age and cell-type, but not sex. In the developing cerebellum, highest levels of ERbeta-immunoreactivity (IR) were detected in neurons during neurite growth, and in some glia during migration. Throughout the first postnatal week, ERbeta-IR was localized to differentiating granule cells in the external germinal layer and to migrating glia. Differentiating granule cells expressed detectable levels of ERbeta throughout development. In Purkinje cells, ERbeta-IR was first detected on postnatal day 6 (P6), with peak intensities of immunostaining coinciding with the initiation of axonal and dendritic growth that occurs between P7 and P8. Expression of ERbeta-IR remained high during maturation of Purkinje cell dendrites, and then decreased to a lower level maintained in the adult. From the third postnatal week, ERbeta-IR was also detected in the later developing Golgi, stellate, and basket neurons. These results suggest that ERbeta may play a role in growth-related mechanisms during differentiation of cerebellar neurons and glia.

Reduced susceptibility of human immunodeficiency virus type 1 (HIV-1) from patients with primary HIV infection to nonnucleoside reverse transcriptase inhibitors is associated with variation at novel amino acid sites

Recently, significant numbers of individuals with primary human immunodeficiency virus (HIV) infection have been found to harbor viral strains with reduced susceptibility to antiretroviral drugs. In one study, HIV from 16% of such antiretroviral-naive individuals was shown to have a susceptibility to nonnucleoside reverse transcriptase (RT) inhibitors (NNRTIs) between 2.5- and 10-fold lower than that of a wild-type control. Mutations in the RT domain that had previously been associated with antiretroviral resistance were not shared by these strains. We have analyzed by logistic regression 46 variable amino acid sites in RT for their effect on susceptibility and have identified two novel sites influencing susceptibility to NNRTIs: amino acids 135 and 283 in RT. Eight different combinations of amino acids at these sites were observed among these patients. These combinations showed a 14-fold range in mean susceptibility to both nevirapine and delavirdine. In vitro mutagenesis of the control strain combined with a phenotypic assay confirmed the significance of amino acid variation at these sites for susceptibility to NNRTIs.

Effect of influenza vaccination on viral replication and immune response in persons infected with human immunodeficiency virus receiving potent antiretroviral therapy

Nineteen patients infected with human immunodeficiency virus (HIV) with varying levels of viral suppression achieved with antiretroviral therapy were evaluated to determine whether trivalent influenza vaccine activated HIV replication. Humoral immune responses and CD4+ lymphocyte subsets were compared in 5 HIV-uninfected vaccinated subjects. Transient elevations of plasma HIV RNA levels (76-89 copies/mL) appeared within 2 weeks in 3 of 11 patients with <50 copies/mL at baseline. Sustained elevation in HIV plasma RNA was observed in 7 of 8 patients with baseline HIV RNA of >50 copies/mL. HIV DNA decreased in patients with <400 RNA copies/mL at baseline and showed an HIV RNA increase after vaccination (n=8) when compared with 8 patients with <50 copies/mL at baseline who lacked viral response to vaccination. Concurrent decreases in proviral DNA and memory phenotype CD4+ cells in association with increased plasma HIV RNA after vaccination in patients with <400 RNA copies/mL at baseline suggest that in vivo mobilization of the latently infected cell reservoir may occur during potent antiretroviral therapy.

Multiple sites in HIV-1 reverse transcriptase associated with virological response to combination therapy

OBJECTIVE

To determine whether analysis of sequence variation in reverse transcriptase at baseline can explain differences in response to combination antiretroviral therapy.

METHODS

Amino acid sequences of reverse transcriptase obtained from baseline isolates from 55 patients included in a trial of zidovudine and didanosine versus zidovudine/didanosine/nevirapine (ACTG241) were analysed. Simple and multiple linear regression were used to determine the relationship between numbers and identity of mutations at baseline and virological response after 8 and 48 weeks.

RESULTS

Numbers of baseline zidovudine resistance mutations were predictive of short-term response (week 8). Amino acid identity at position 215 explained > 20% of the variation in response at week 8, but less at week 48. Multiple regression identified the combinations: 215 + 44 and 41 + 202, each of which explained about 30% of the variation in week 8 response. A model incorporating amino acids 214 + 215 + 60 + 202 + baseline viral load explained > 40% of the variation in response at week 48. Unexpectedly, the mutant combination 601 + 215Y/F responded threefold better than 60V + 215Y/F over 48 weeks.

CONCLUSIONS

Use of clinical data to analyse virological response to combination therapy has revealed effects of baseline amino acid mutations at sites not previously identified as being important in antiretroviral resistance. Predictors of long-term responses were different from those involved in the short term and may require more complex analysis.

Rapid accumulation of human immunodeficiency virus (HIV) in lymphatic tissue reservoirs during acute and early HIV infection: implications for timing of antiretroviral therapy

The follicular dendritic cell network (FDC) in lymphoid tissues (LTs) is the major site of human immunodeficiency virus (HIV) storage in presymptomatic and late stages of disease. However, little is known about the rate of virus accumulation during the acute and early stages. In situ hybridization and quantitative image analysis were used to determine the amount of virus bound to the FDC network during the first year of infection. The FDC pool was already >7.0 log10 copies of HIV RNA/g LT in the first year, and 2 patients biopsied within 2-4 days of symptom onset had 7.3 and 8.2 log10 copies of HIV RNA/g LT, respectively. There was no correlation between duration of infection and accumulation of HIV into the FDC network. These data suggest that a large pool of infectious virus is established soon after infection and that initiation of antiretroviral therapy when symptoms of primary HIV infection are recognized is unlikely to prevent substantial accumulation of virus in the FDC network.

Synthesis of C-11 methyl-substituted benzocycloheptapyridine inhibitors of farnesyl protein transferase

[formula: see text] Synthesis of C-11 methyl-substituted benzocycloheptylpyridine tricyclic compounds has been achieved via two different methods. Methylation of C-11 has been effected by treatment of amine 4 with BuLi followed by Mel quenching. In a similar procedure, introduction of a C-11 substituent with concomitant rearrangement of the exocyclic double bond has been carried out. Potent farnesyl protein transferase inhibitors have been synthesized using the above methodologies.

Evolution of envelope sequences of human immunodeficiency virus type 1 in cellular reservoirs in the setting of potent antiviral therapy

In human immunodeficiency virus (HIV)-infected patients treated with potent antiretroviral therapy, the persistence of latently infected cells may reflect the long decay half-life of this cellular reservoir or ongoing viral replication at low levels with continuous replenishment of the population or both. To address these possibilities, sequences encompassing the C2 and V3 domains of HIV-1 env were analyzed from virus present in baseline plasma and from viral isolates obtained after 2 years of suppressive therapy in six patients. The presence of sequence changes consistent with evolution was demonstrated for three subjects and correlated with less complete suppression of viral replication, as indicated by the rapidity of the initial virus load decline or the intermittent reappearance of even low levels of detectable viremia. Together, these results provide evidence for ongoing replication. In the remaining three patients, virus recovered after 2 years of therapy was either genotypically contemporary with or ancestral to virus present in plasma 2 years before, indicating that virus recovery had indeed resulted from activation of latently infected cells.

Sequence clusters in human immunodeficiency virus type 1 reverse transcriptase are associated with subsequent virological response to antiretroviral therapy

Many amino acid (aa) sites in reverse transcriptase (RT) have been implicated in resistance to nucleoside (NRTI) and nonnucleoside antiretrovirals. Interactions between these in response to combination therapy remain poorly understood. In a trial (ACTG 241) of zidovudine/didanosine (ddI) versus zidovudine/ddI/nevirapine in nucleoside-experienced patients, baseline sequence data from the RT coding region was analyzed from 55 individuals. Sequences were clustered by use of a parsimony method and the virological responses (ratio of baseline viral load to viral load after of therapy) for each cluster were analyzed at week 8 and week 48. Both clusters and genotype at aa 215 were significantly associated with virological response at both time points, whereas viral load showed a stronger association with sequence clusters. Sequence clusters identified one group of patients who never developed high-level resistance to NRTIs despite prior nucleoside exposure and poor suppression of viral replication.

Higher selection pressure from antiretroviral drugs in vivo results in increased evolutionary distance in HIV-1 pol

We investigated the effect of selection pressures on evolution of HIV-1 pol in 51 patients after switching to a new antiretroviral combination reverse transcriptase (RT) inhibitor therapy. Evolution of the protease (PR) and RT reading frames were analysed separately. Pairwise evolutionary distances (ED) were calculated between sequences from baseline and week 8 and between baseline and week 48 of protocol therapy. ED were calculated for all substitutions and for synonymous and nonsynonymous substitutions separately. At week 8 when HIV RNA reduction (selection pressure) was high, significantly more divergence in pol in both synonymous and nonsynonymous substitutions was found in patients with substantial RNA reduction (strong responders). Separate analyses of PR and RT revealed significantly greater ED in the RT (under selection pressure) of strong compared with nonresponders, whereas divergence between PR genes (not under selection pressure) did not differ in those two groups. Such differential evolution indicates that PR and RT were genetically unlinked and suggests recombination. The rapid increase of ED over the first 8 weeks was followed by only a minimal further rise by week 48, suggesting that selection of preexisting quasispecies accounted for the early changes. A disproportionally high number of synonymous substitutions accounted for the observed divergence and indicated that such genetic changes may not be completely silent.

A comparison of bitemark injuries between fatal wolf and domestic dog attacks

Bitemark patterns in adult human victims following a fatal wolf pack attack and a domestic dog pack attack are compared. Both victims exhibited a concentration of wounds to the extremities, left and right torso, but not to the groin or internal organs. The neck and face of the domestic dog attack victim were primary sites of attack while the feral wolf pack victim was spared damage to the neck, but had facial tissue destroyed postmortem. Most punctures were found on the ventral aspect of the domestic victim and dorsal aspect of the feral victim. It is speculated that most wounds were attributable to dominant animals of both packs and in both victims and this suggests a co-ordination of activity between. Differences in bitemark patterns may well have been caused in part by differences in genetics, training, breeding, socialization and impetus of attack between wolves and dogs. Distinct differences in bitemark patterns were found in these two human victims of a wolf and domestic dog attacks.

Use of the intubating laryngeal mask airway to facilitate awake orotracheal intubation in patients with cervical spine disorders

Airway management in patients with unstable cervical spines remains a challenge for anesthesia providers. Because neurologic evaluations may be required following tracheal intubation and positioning for the surgical procedure, an awake intubation technique is desirable in this patient population. In this report, we describe the use of an intubating laryngeal mask airway (ILMA) to facilitate awake tracheal intubation in two patients with cervical spine disorders. After topical local analgesia, the ILMA was inserted easily, and a tracheal tube was passed through the glottic opening without complications. Thus, the ILMA may be an acceptable alternative to the fiberoptic bronchoscope for awake tracheal intubation.

Comparison of two Doppler ultrasound criteria for grading cervical internal carotid artery stenosis

In a review of 49 carotid arteries that had been assessed by ultrasound and angiography, two Doppler criteria were compared for accuracy in grading internal carotid artery (ICA) stenosis. The Seattle criteria for Doppler spectral analysis and the internal-to-common carotid artery peak systolic velocity ratio were of similar accuracy. When used in combination, there was an increase in sensitivity compared with the use of a single criterion. The velocity ratio had a higher sensitivity for detection of high-grade stenosis, but it tended to overestimate the grade of stenosis more than the Seattle criteria. To increase the sensitivity for detection of severe stenosis, the criteria should be used together and the higher grade of stenosis should be taken if there is a mismatch in assessment.

Reversibility of the pathological changes in the follicular dendritic cell network with treatment of HIV-1 infection

Over the course of HIV-1 infection, the lymphoid follicles where the humoral immune response is generated initially increase in size and number and then progressively involute. In advanced disease, the network of the processes of follicular dendritic cells (FDCs) that serve as antigen repositories and anatomical substrate for B and T cells and antigen to interact is destroyed, contributing to the breakdown of the immune system. Because destruction of FDCs is associated with deposition of HIV-1, and much of the virus can be cleared from the network with antiretroviral therapy, we investigated the reversibility of damage. We measured the immunohistochemically stainable FDC compartment by quantitative image analysis, and we documented changes in this compartment at different stages of disease. We show that treatment, initiated even at advanced stages of HIV-1 disease, can slowly reverse pathological changes in the FDC network.

Predicting infection in localized intraabdominal fluid collections: value of pH and pO2 measurements

PURPOSE

To evaluate the use of pH, pO2, and the subjective opinion of the radiologist compared with bacterial culture in accurate diagnoses of bacterial infection in intraabdominal fluid collections.

MATERIALS AND METHODS

Prospectively, 79 patients who were suspected of having an intraabdominal fluid collection underwent diagnostic fluid aspiration. The aspirate was cultured and measured for pH and pO2. A pH < or = 7.1 and a PO2 < or = 49 mm Hg were threshold values used to separate infected from sterile fluid collections.

RESULTS

pH alone had a 92% sensitivity and 79% specificity, whereas PO2 alone had a 51% sensitivity and 79% specificity. pH or pO2 combined yielded a 92% sensitivity and 60% specificity. The radiologist's opinion produced a 83% sensitivity and 92% specificity. pH and the radiologist's opinion combined produced a 78% sensitivity and 96% specificity. pH or the radiologist's opinion combined had a 95% sensitivity and a 63% specificity.

CONCLUSION

pH is the most sensitive indicator of infection and the radiologist's opinion is the most specific. We recommend proceeding to drainage if the radiologist believes the collection to be infected and performing pH analysis if not. If the pH < or = 7.04, proceed to drainage. If neither of the above criteria are met, drainage could be delayed, pending the results of culture.