The clinical spectrum of HbSC sickle cell disease-not a benign condition.

Sickle cell disease (SCD) includes a group of heterogenous disorders that result in significant morbidities. HbSS is the most common type of SCD and HbSC is the second most common type of SCD. The prevalence of HbSC disease in the United States and United Kingdom is ~1 in 7174 births and 1 in 6174 births respectively. Despite its frequency, however, HbSC disease has been insufficiently studied and was historically categorized as a more 'mild' form of SCD. We conducted this study of HbSC disease as part of the NHLBI funded Sickle Cell Disease Implementation Consortium (SCDIC). The SCDIC registry included 2282 individuals with SCD, ages 15-45 years of whom 502 (22%) had HbSC disease. Compared with people with sickle cell anaemia (SCA), the study found that people with HbSC disease had a higher frequency of splenomegaly (n (%) = 169 (33.7) vs. 392 (22.1)) and retinopathy (n (%) = 116 (23.1) vs. 189 (10.6)). A Many people with HbSC also had avascular necrosis (n (%) = 112 (22.3)), pulmonary embolism (n (%) = 43 (8.6)) and acute chest syndrome (n (%) = 228 (45.4)) demonstrating significant disease severity. HbSC disease is more clinically severe than was previously recognized and deserves additional evaluation and targeted treatments.

Immobilization of biotinylated antibodies through streptavidin binding aptamer.

Liquid biopsy approaches are powerful strategies that potentially allow the diagnosis and prognosis of a number of diseases. The field is continuously and rapidly growing, encouraging the discovery of novel predictory biomarkers. Antibodies are usually exploited in sensors to validate biomarker candidates. Unfortunately, the immobilization of antibodies on the surface of sensors represents a challenging task. Immobilization strategies need to be optimized for each antibody, representing a huge obstacle to overcome in the discovery of new biomarkers. Herein we propose a novel strategy for the immobilization of antibodies, based on the use of a streptavidin-binding aptamer. Using this approach it is possible to immobilize antibodies on the surface of sensors with no need for optimization, with the only requirement for antibody to be biotinylated. The proposed strategy potentially paves the way towards a straightforward immobilization of antibodies on biosensors, making their use in biomarker validation more accessible.

Treating brain diseases using systemic parenterally-administered protein therapeutics: Dysfunction of the brain barriers and potential strategies.

The parenteral administration of protein therapeutics is increasingly gaining importance for the treatment of human diseases. However, the presence of practically impermeable blood-brain barriers greatly restricts access of such pharmaceutics to the brain. Treating brain disorders with proteins thus remains a great challenge, and the slow clinical translation of these therapeutics may be largely ascribed to the lack of appropriate brain delivery system. Exploring new approaches to deliver proteins to the brain by circumventing physiological barriers is thus of great interest. Moreover, parallel advances in the molecular neurosciences are important for better characterizing blood-brain interfaces, particularly under different pathological conditions (e.g., stroke, multiple sclerosis, Parkinson's disease, and Alzheimer's disease). This review presents the current state of knowledge of the structure and the function of the main physiological barriers of the brain, the mechanisms of transport across these interfaces, as well as alterations to these concomitant with brain disorders. Further, the different strategies to promote protein delivery into the brain are presented, including the use of molecular Trojan horses, the formulation of nanosystems conjugated/loaded with proteins, protein-engineering technologies, the conjugation of proteins to polymers, and the modulation of intercellular junctions. Additionally, therapeutic approaches for brain diseases that do not involve targeting to the brain are presented (i.e., sink and scavenging mechanisms).

A multicentre study investigating vital sign changes occurring in complicated and uncomplicated transfusions.

BACKGROUND AND OBJECTIVES: Many hospitals require transfusions to be discontinued when vital signs stray from predetermined ranges, regardless of clinical symptoms. Variations in vital signs may be unrelated to transfusion, however, and needlessly stopping a transfusion may delay medical care while increasing donor exposures and healthcare costs. We hypothesized that a detailed study of vital sign changes associated with transfusion of blood product by component, including those associated with potential reactions (complicated) and those deemed to be uncomplicated, would establish a useful framework of reference for treating clinicians and transfusion services alike. MATERIALS AND METHODS: A retrospective electronic record review of transfusion service and transfusion recipient data was completed on 3852 inpatient transfusion episodes over a 6-month period at four academic tertiary care hospitals across the United States. Vital signs pre- and post-transfusion were recorded by trained clinical research nurses. Serious reactions were adjudicated by a panel of transfusion medicine experts. RESULTS: In both uncomplicated transfusions (n = 3765) and those including an adverse reaction (n = 87), vital sign fluctuations were generally modest. Compared to uncomplicated transfusions, transfusions complicated by febrile reactions were associated with higher pretransfusion temperature and higher pretransfusion pulse rates. Episodes of transfusion circulatory overload were associated with higher pretransfusion respiration rates compared to uncomplicated transfusions. CONCLUSION: Most transfusions are associated with only modest changes in vital signs. Pretransfusion vital signs may be an important yet previously understudied predictor of vital sign changes during transfusion. The optimal role of vital sign assessment during blood transfusion deserves further study.

Incidence and clinical characteristics of transfusion-associated circulatory overload using an active surveillance algorithm.

BACKGROUND: The concordance of haemovigilance criteria developed for surveillance of transfusion-associated circulatory overload (TACO) with its clinical diagnosis has not been assessed. In a pilot study to evaluate an electronic screening algorithm, we sought to examine TACO incidence and application of haemovigilance criteria in patients with post-transfusion pulmonary oedema. STUDY DESIGN AND METHODS: From June to September 2014, all transfused adult inpatients at four academic hospitals were screened with an algorithm identifying chest radiographs ordered within 12 h of blood component release. Patients with post-transfusion pulmonary oedema underwent case adjudication by an expert panel. TACO incidence was calculated, and clinical characteristics were compared with other causes of post-transfusion pulmonary oedema. RESULTS: Among 4932 transfused patients, there were 3412 algorithm alerts, 50 cases of TACO and 47 other causes of pulmonary oedema. TACO incidence was 1 case per 100 patients transfused. TACO classification based on two sets of haemovigilance criteria (National Healthcare Safety Network and proposed revised International Society for Blood Transfusion) was concordant with expert panel diagnosis in 57% and 54% of reviewed cases, respectively. Although the majority of clinical parameters did not differentiate expert panel adjudicated TACO from other cases, improved oxygenation within 24 h of transfusion did (P = 0·01). CONCLUSIONS: The incidence of TACO was similar to that observed in prior studies utilizing active surveillance. Case classification by haemovigilance criteria was frequently discordant with clinical diagnoses of TACO in patients with post-transfusion pulmonary oedema. Improvements in oxygenation within 24 h of transfusion merit further evaluation in the diagnosis of TACO.

Application of Nanomedicine to the CNS Diseases.

Drug delivery to the brain is a challenge because of the many mechanisms that protect the brain from the entry of foreign substances. Numerous molecules which could be active against brain disorders are not clinically useful due to the presence of the blood-brain barrier. Nanoparticles can be used to deliver these drugs to the brain. Encapsulation within colloidal systems can allow the passage of nontransportable drugs across this barrier by masking their physicochemical properties. It should be noted that the status of the blood-brain barrier is different depending on the brain disease. In fact, in some pathological situations such as tumors or inflammatory disorders, its permeability is increased allowing very easy translocation of carriers. This chapter gathers the promising results obtained by using nanoparticles as drug delivery systems with the aim to improve the therapy of some CNS diseases such as brain tumor, Alzheimer's disease, and stroke. The data show that several approaches can be investigated: (1) carrying drug through a permeabilized barrier, (2) crossing the barrier thanks to receptor-mediated transcytosis pathway in order to deliver drug into the brain parenchyma, and also (3) targeting and treating the endothelial cells themselves to preserve locally the brain tissue. The examples given in this chapter contribute to demonstrate that delivering drugs into the brain is one of the most promising applications of nanotechnology in clinical neuroscience.

Von Willebrand factor for menorrhagia: a survey and literature review.

BACKGROUND: von Willebrand disease (VWD) is the most common congenital bleeding disorder. In women, menorrhagia is the most common bleeding symptom, and is disabling with iron deficiency anaemia, high health cost and poor quality of life. Current hormonal and non-hormonal therapies are limited by ineffectiveness and intolerance. Few data exist regarding von Willebrand factor (VWF), typically prescribed when other treatments fail. The lack of effective therapy for menorrhagia remains the greatest unmet healthcare need in women with VWD. Better therapies are needed to treat women with menorrhagia. METHODS: We conducted a survey of US haemophilia treatment centres (HTCs) and a literature review using medical subject heading (MeSH) search terms 'von Willebrand factor,' 'menorrhagia' and 'von Willebrand disease' to assess the use of VWF in menorrhagia. Analysis was by descriptive statistics. RESULTS: Of 83 surveys distributed to HTC MDs, 20 (24.1%) provided sufficient data for analysis. Of 1321 women with VWD seen during 2011-2014, 816 (61.8%) had menorrhagia, for which combined oral contraceptives, tranexamic acid and desmopressin were the most common first-line therapies for menorrhagia, whereas VWF was third-line therapy reported in 13 women (1.6%). Together with data from 88 women from six published studies, VWF safely reduced menorrhagia in 101 women at a dose of 33-100 IU kg(-1) on day 1-6 of menstrual cycle. CONCLUSIONS: This represents the largest VWD menorrhagia treatment experience to date. VWF safely and effectively reduces menorrhagia in women with VWD. A prospective clinical trial is planned to confirm these findings.

Fluorodeoxyglucose positron emission tomography in pulmonary carcinoid tumors.

AIM: The role of fluorodeoxyglucose positron emission tomography (FDG-PET) as an additional investigation to computer tomography for pulmonary carcinoid tumors remains controversial. The aim of this study was to assess the role of FDG-PET for the diagnosis and staging of pulmonary carcinoid tumors. METHODS: We performed a retrospective mono-institutional analysis of data from 97 patients with pathologically confirmed pulmonary carcinoid tumor who had been operated on between July 1998 and April 2009 and had had a preoperative FDG-PET scan performed. RESULTS: Sixty-five (67%) of the 97 tumors were typical (TC) and 32 (33%) atypical (AC) carcinoid tumors. Overall FDG-PET sensitivity was 67% being lower for TC (60%) than for AC (81%) (P=0.04). FDG-PET negative tumors were smaller than FDG-PET positive tumors, with a respective median size of 15 and 17 mm (P=0.02). Median SUVmax for FDG-PET-positive tumors was 4.0 (2.8-5.1) with no difference between TC and AC tumors. Median Ki-67 expression was respectively 4.7% and 3.1% for FDG-PET positive and FDG-PET negative tumors (P=0.05). During a median follow-up of 49 months (interquartile range 30-63 months), 9 patients (4TC, 5AC) developed recurrent disease. Neither SUVmax nor Ki-67 expression resulted associated with disease-free survival. CONCLUSION: With an overall sensitivity of 67%, FDG-PET has shown to be useful in the preoperative work-up of patients with suspect lung carcinoid tumors. In particular it could have a role in larger tumors. These results warrant a prospective evaluation of FDG-PET in the staging of lung carcinoid tumor.

Effect of eye lateralization on contralateral suppression of transient evoked otoacoustic emissions.

Several studies have previously demonstrated that postural changes modify evoked otoacoustic emission. In order to evaluate a possible interaction between eye muscles and ciliated cells in the inner ear, we studied the effects of eye lateralization on the contralateral suppression of transient evoked otoacoustic emissions (TEOAEs). Thirty-eight normal hearing subjects with TEOAEs were recruited. Their TEAOEs at threshold level were recorded with contralateral suppression (white noise) via straight ahead fixation and right or left lateral fixation. Eye lateralization in the same direction of the white noise significantly decreased the suppression at 4 kHz (p = 0.003). The signal-to-noise ratio in the suppression condition with straight ahead was 1.54 (± 4.610) dB, while the ratio was 3.48 (± 4.631) dB in the suppression condition with gaze toward the white noise. Eye lateralization seems to reduce the contralateral suppression effect of TEOAEs at 4 kHz. However, further studies are necessary to investigate the possible mechanisms of this phenomenon.

Long-term results of iliac aneurysm repair with iliac branched endograft: a 5-year experience on 100 consecutive cases.

BACKGROUND: Iliac branch device (IBD) technique has been introduced as an appealing and effective solution to avoid complications occurring during repair of aorto-iliac aneurysm with extensive iliac involvement. Nevertheless, no large series with long-term follow-up of IBD are available. The aim of this study was to analyse safety and long-term efficacy of IBD in a consecutive series of patients. METHODS: Between 2006 and 2011, 100 consecutive patients were enrolled in a prospective database on IBD. Indications included unilateral or bilateral common iliac artery aneurysms combined or not with abdominal aneurysms. Patients were routinely followed up with computed tomography. Data were reported according to the Kaplan-Meier method. RESULTS: There were 96 males, mean age 74.1 years. Preoperative median common iliac aneurysm diameter was 40 mm (interquartile range (IQR): 35-44 mm). Sixty-seven patients had abdominal aortic aneurysm >35 mm (IQR: 40-57 mm) associated with iliac aneurysm. Eleven patients presented hypogastric aneurysm. Twelve patients underwent isolated iliac repair with IBD and 88 patients received associated endovascular aortic repair. Periprocedural technical success rate was 95%, with no mortality. Two patients experienced external iliac occlusion in the first month. At a median follow-up of 21 months (range 1-60) aneurysm growth >3 mm was detected in four iliac (4%) arteries. Iliac endoleak (one type III and two distal type I) developed in three patients and buttock claudication in four patients. Estimated patency rate of internal iliac branch was 91.4% at 1 and 5 years. Freedom from any reintervention rate was 90% at 1 year and 81.4% at 5 years. No late ruptures occurred. CONCLUSIONS: Long-term results show that IBD use can ensure persistent iliac aneurysm exclusion at 5 years, with low risk of reintervention. This technique can be considered as a first endovascular option in patients with extensive iliac aneurysm disease and favourable anatomy.

Risk factors for inhibitor formation in haemophilia: a prevalent case-control study.

Inhibitor formation is a major complication of haemophilia treatment. In a prevalent case-control study, we evaluated blood product exposure, genotype and HLA type on haemophilia A inhibitor formation. Product exposure was extracted from medical records. Genotype was determined on stored DNA samples by detection of virtually all mutations-SSCP (DOVAM-S) and subcycling PCR. HLA typing was performed by PCR amplification and exonuclease-released fluorescence. Cases experienced higher intensity factor, 455 vs. 200 U per exposure, P < 0.005, more frequent central nervous system (CNS) bleeding, seven of 20 (35.0%) vs. one of 57 (1.7%), P = 0.001 and more commonly from inhibitor families, seven of 20 (35.0%) vs. zero of 57 (0%), P < 0.001, and African-American, 12 of 63 (19.0%) vs. six of 117 (5.1%), P = 0.015. Among the latter, CNS bleeding was more commonly the initial bleed, 60% vs. 0%, P < 0.001, and survival was shorter, 14 vs. 38 yr, P = 0.025. Inhibitor formation was uncommon in those with missense mutations, two of 65 (3.1%) vs. 31 of 119 (26.0%), P = 0.008, and unrelated to factor VIII immunogenic epitope, P = 0.388, or HLA type, P > 0.100. Genotype was not associated with race. Time to immune tolerance was shorter for titres <120 vs. > or = 120 BU/mL, six vs. 16 months, P < 0.01, but unaffected by tolerizing dose regimen, P > 0.50. Inhibitor formation is associated with high intensity product exposure, CNS bleeding, African-American race and low frequency of missense mutations. The ideal time to initiate prophylaxis to reduce CNS bleeding and inhibitor formation will require prospective studies.

Molecular characterization and phylogenetic analysis of human influenza A viruses in three consecutive seasons with different epidemiological profiles.

INTRODUCTION: Influenza activity and influenza virus circulation were observed in Lombardy (northern Italy) during three consecutive seasons and the molecular characteristics of circulating viruses analysed to control for introduction of new variants. METHODS: The molecular characterization of 38 isolates, namely 20 A/H3N2 and 18 A/H1N1 influenza strains from the 2005/06, 2006/07 and 2007/08 seasons, was performed by sequence analysis of the globular head region of the HA protein (HA1 subunit), specific for influenza virus A/H3 and A/H1. RESULTS AND DISCUSSION: The last three influenza seasons in the study region were characterized by medium-low activity. A typical co-circulation of several variants was shown for A/H3 viruses for approximately two years and were subsequently almost entirely substituted by new emerging variants. Vice versa, A/H1 viruses had a more homogeneous circulation with a single lineage clearly dominating each season. The HA sequences of the A/H3 and the A/H1 viruses isolated in the last three seasons fell into 4 and 3 principal phylogenetic groups, respectively. No evidence of positive or negative selection in the sequence alignments was observed. CONCLUSIONS: Molecular characterization of the influenza viruses in three consecutive seasons highlighted considerable heterogeneity in their HA sequences. A careful surveillance of genetic changes in the HA1 domain during seasonal influenza epidemics may reveal immune escape and provide early information on newly emerging strains with epidemiologic inference.

Outcome after endografting in small and large abdominal aortic aneurysms: a metanalysis.

AIM: To compare the results of endovascular repair (EVAR) in large and small (diameter < 5.5cm) abdominal aortic aneurysms (AAA). METHODS: A systematic review was performed to identify studies comparing the outcomes after EVAR of large and small aneurysms. Outcomes considered were: risk of death (perioperative, all cause, aneurysm-related), ruptures, and complications (conversion, reintervention). Weighted pooled estimates of outcomes in patients with small versus large aneurysms were calculated. The inverse variance method was used (random-effect model). Subgroup analyses by a follow-up longer or shorter than 24 months were performed. RESULTS: Five studies, with published and unpublished data, totallying 7,735 patients, were included. Overall, the weighted pooled estimates were: OR 0.68; 95% CI 0.51-0.90 for operative mortality, OR 0.77; 95% CI 0.69 to 0.86 for all cause mortality, OR 0.58; 95% CI 0.40 to 0.87 for aneurysm-related mortality and OR 0.61; 95% CI 0.47 to 0.79 for rupture in favour of small AAA group. Pooled estimates were not influenced by follow-up length. Conversion and reintervention rates were not significantly lower for small AAA. CONCLUSIONS: EVAR in small versus large AAA might be associated with lower operative mortality, aneurysm-related mortality and aneurysm rupture. Better evidence is needed to support these suggestions.

Tissue plasminogen activator to prevent central venous access device infections: a systematic review of central venous access catheter thrombosis, infection and thromboprophylaxis.

The recent unequivocal demonstration that prophylaxis, three to four weekly factor infusions, is effective in preventing joint disease in children with haemophilia, has provided impetus to initiate prophylaxis early in such children. Yet, nearly a quarter (22%) of the 83% who required central venous access devices for factor infusion developed central venous access catheter (CVAD)-related infection. This limitation of CVAD use prevents many families from initiating prophylaxis. The frequent occurrence of local thrombosis accompanying CVAD-related infection in surgical patients and autopsy cases, the thrombogenic plastic CVAD surfaces, and local clot formation at the insertion site, suggest the potential role of thrombolytic agents in preventing these infections. Yet, correlation between CVAD-related infection and local thrombosis in children with haemophilia are lacking, and thromboprophylaxis to prevent CVAD-related infection is controversial. Tissue plasminogen activator (t-PA), a recombinant serine protease glycoprotein that lyses plasmin-bound fibrin and is safe and effective in the treatment of occluded catheters, has not been evaluated in the prevention of these infections. We performed a literature review of CVAD-related infection, CVAD-related thrombosis, and thromboprophylaxis studies to evaluate the role of t-PA in the prevention of these infections in children with haemophilia. Metanalysis of published thromboprophylaxis trials demonstrate current prophylaxis regimens do not prevent CVAD infection, and further, that thrombosis and infection do not necessarily occur simultaneously. Pilot data demonstrate CVAD infection reduction in haemophilic children by monthly t-PA in 18 haemophilic children, suggesting the potential role of t-PA in CVAD infection prevention. Clinical trials to evaluate t-PA in CVAD infection prevention are justified.

Interleukin-1 inhibits firing of serotonergic neurons in the dorsal raphe nucleus and enhances GABAergic inhibitory post-synaptic potentials.

In vitro electrophysiological data suggest that interleukin-1 may promote non-rapid eye movement sleep by inhibiting spontaneous firing of wake-active serotonergic neurons in the dorsal raphe nucleus (DRN). Interleukin-1 enhances GABA inhibitory effects. DRN neurons are under an inhibitory GABAergic control. This study aimed to test the hypothesis that interleukin-1 inhibits DRN serotonergic neurons by potentiating GABAergic inhibitory effects. In vitro intracellular recordings were performed to assess the responses of physiologically and pharmacologically identified DRN serotonergic neurons to rat recombinant interleukin-1beta. Coronal slices containing DRN were obtained from male Sprague-Dawley rats. The impact of interleukin-1 on firing rate and on evoked post-synaptic potentials was determined. Evoked post-synaptic potentials were induced by stimulation with a bipolar electrode placed on the surface of the slice ventrolateral to DRN. Addition of interleukin-1 (25 ng/mL) to the bath perfusate significantly decreased firing rates of DRN serotonergic neurons from 1.3 +/- 0.2 Hz (before administration) to 0.7 +/- 0.2 Hz. Electrical stimulation induced depolarizing evoked post-synaptic potentials in DRN serotonergic neurons. The application of glutamatergic and GABAergic antagonists unmasked two different post-synaptic potential components: a GABAergic evoked inhibitory post-synaptic potentials and a glutamatergic evoked excitatory post-synaptic potentials, respectively. Interleukin-1 increased GABAergic evoked inhibitory post-synaptic potentials amplitudes by 30.3 +/- 3.8% (n = 6) without affecting glutamatergic evoked excitatory post-synaptic potentials. These results support the hypothesis that interleukin-1 inhibitory effects on DRN serotonergic neurons are mediated by an interleukin-1-induced potentiation of evoked GABAergic inhibitory responses.

Redox options in two-dimensional electrophoresis.

Two-dimensional electrophoresis is usually run on fully reduced samples. Under these conditions even covalently bound oligomers are dissociated and individual polypeptide chains may be fully unfolded by both, urea and SDS, which maximizes the number of resolved components and allows their pI and M(r) to be most accurately evaluated. However, various electrophoretic protocols for protein structure investigation require a combination of steps under varying redox conditions. We review here some of the applications of these procedures. We also present some original data about a few related samples -- serum from four species: Homo sapiens, Mus musculus, Rattus norvegicus, Bos taurus -- which we run under fully unreduced and fully reduced conditions as well as with reduction between first and second dimension. We demonstrate that in many cases the unreduced proteins migrate with a better resolution than reduced proteins, mostly in the crowded 'alpha-globulin' area of pI 4.5-6 and M(r) 50-70 kDa.

Electrophysiological analysis of cognitive slowing in subjects with mitochondrial encephalomyopathy.

Mitochondrial encephalomyopathies (MEs) are multisystemic inherited disorders affecting tissues with high energy requirement such as the muscle, retina and central nervous system. Progressive external ophthalmoplegia and myopathy are the most common features in adults, and cognitive impairment is rare. In many neurodegenerative disorders, ERPs have been effectively performed to record cognitive slowing on tasks with different amount of information. To analyze the evidence for possible cognitive slowing, a standard auditory oddball paradigm with a button-press response was applied. Participants were 11 non-demented patients affected by mitochondrial encephalomyopathy and 14 age-matched normal controls. This hypothesis was tested using two tasks of different difficulty (pure tone vs. phonetic stimuli). Reaction time (RT), performance (P) and event-related potentials (ERPs) were measured. RT and P were not significantly different between the groups. Patients showed significantly increased N2 latency and reduced P3 amplitude on both tasks. No difference was found in pure tone and phonetic task conditions. Results were interpreted as electrophysiological signs of cognitive slowing--particularly in relation to stimulus evaluation--irrespective of sensory problems, response selection and cognitive load. These findings suggest that in ME patients, there may be a possible dysfunction of neural mechanisms underlying cognitive events and ERP generation.

Silent infarcts in children with sickle cell anemia and abnormal cerebral artery velocity.

BACKGROUND: A substantial minority of neurologically normal children with sickle cell disease have lesions consistent with cerebral infarction as seen on magnetic resonance imaging (MRI). OBJECTIVES: To determine if transfusion therapy affects the rate at which silent infarcts develop and to evaluate the contribution of MRI of the brain to stroke prediction by transcranial Doppler (TCD) ultrasonography. STUDY DESIGN: Children with elevated TCD ultrasonographic velocity were randomized to receive long-term transfusion therapy or standard care. Magnetic resonance imaging of the brain was obtained at randomization, annually, and with clinical neurologic events. The risk for new silent lesions and/or stroke was compared for each treatment arm. RESULTS: Among the 37% of subjects with silent infarcts, those receiving standard care were significantly more likely to develop new silent lesions or stroke than were those who received transfusion therapy. For subjects receiving standard care, those with lesions at baseline were significantly more likely to develop stroke or new silent lesions than those whose MRI studies showed no abnormality. CONCLUSIONS: Transfusion therapy lowers the risk for new silent infarct or stroke for children having both abnormal TCD ultrasonographic velocity and silent infarct. However, those with both abnormalities who are not provided transfusion therapy are at higher risk for developing a new silent infarct or stroke than are those whose initial MRI showed no abnormality. The finding of a silent infarct reinforces the need for TCD ultrasonographic screening and consideration of transfusion therapy if the abnormalities are seen. Similarly, elevated TCD ultrasonographic velocity warrants MRI of the brain because children with both abnormalities seem to be at increased risk for developing new silent infarct or stroke.

Longitudinal variability of human immunodeficiency virus type 1 RNA viral load measurements by nucleic acid sequence-based amplification and NucliSens assays in a large multicenter study.

Human immunodeficiency virus type 1 (HIV-1) RNA measurements were evaluated within an externally controlled multilaboratory program. Three external standards (1.5 x 10(3) to 1.5 x 10(6) copies/ml) were included in 814 assay runs by four laboratories. Results indicate that HIV-1 RNA levels can be measured with a precision equal to that of the pre-highly active antiretroviral therapy era (standard deviations, +/-0.16 to 0.25 log10 units).