In vivo comparison of two through-plane MR velocity mapping methods: Fast fourier encoding and phase mapping

Magnetic resonance imaging maps of velocity were acquired with a 1.5-T system in 10 subjects in a plane perpendicular to the main pulmonary artery. Velocity images were successively acquired with a method developed from Fourier-encoding velocity imaging (FEVI) principles with eight gradient steps and one excitation, and with two-point phase-subtraction mapping. Reconstruction in FEVI was implemented by zero-filling interpolation around the eight gradient steps and then around the four central steps. The methods were compared by using estimates of noise in velocity measurements based on the difference between the experimental map and a smooth fitted map. For the same acquisition time, FEVI with four encoding steps was more precise in velocity measurements than phase mapping. Precision was further increased by the use of eight encoding steps, but acquisition time was doubled.     

Functional signatures of protective antiviral T-cell immunity in human virus infections

Summary: The most common human viruses have different abilities to establish persistent chronic infection. Virus‐specific T‐cell responses are critical in the control of virus replication and in the prevention of disease in chronic infection. A large number of phenotypic markers and a series of functions have been used to characterize virus‐specific CD4⁺ and CD8⁺ T‐cell responses, and these studies have shown great phenotypic and functional heterogeneity of the T‐cell responses against different viruses. The heterogeneity of the T‐cell response has been proposed to be specific to each virus. However, over the past 2 years, several studies have provided evidence that the phenotypic and functional heterogeneity of CD4⁺ and CD8⁺ T‐cell responses is predominantly regulated by the levels of antigen load. The levels of antigen load modulate the phenotypic and functional patterns of the T‐cell response within the same virus infection. Furthermore, the functional characterization of virus‐specific CD4⁺ and CD8⁺ T‐cell responses has identified signatures of protective antiviral immunity. Polyfunctional, i.e. interleukin‐2 and interferon‐γ (IFN‐γ) secretion and proliferation, and not monofunctional, i.e. IFN‐γ secretion, CD4⁺ and CD8⁺ T‐cell responses represent correlates of protective antiviral immunity in chronic virus infections.     

Radioiodinated tracers for the evaluation of dopamine receptors in the neonatal rat brain after hypoxic-ischemic injury

In order to evaluate in vivo single-photon emission tomography (SPET) method of assessing cerebral function after hypoxic-ischemic injury in human neonates, we studied D₁ and D₂ dopamine receptors in a rat model. Seven-day-old rats underwent permanent unilateral common carotid ligation followed by exposure to 8% O₂. Two weeks later, in brains with no visible loss of hemispheric volume, striatal dopaminergic receptors were studied, with [¹²⁵I]TISCH and [1251]IBZM for the D₁ and D₂ dopamine receptors, respectively. Using [¹²⁵I]TISCH, we observed no modifications of D₁ receptors, but in contrast, ex vivo and in vitro autoradiographic experiments showed a 40% decrease in the striatal binding of [¹²⁵I]IBZM on both the ipsilateral and the contralateral side to the carotid ligation. These alterations were detected with IBZM, a D₂ dopamine receptor ligand usable for SPET imaging. Therefore, exploration of D₂ receptors by SPET in human neonates suffering from perinatal hypoxia-ischemia may be valuable for the diagnosis and follow-up of cerebral function damages. Correspondence to: D. Guilloteau     

Endothelin-1 in children with chronic renal failure

Endothelin-1 (ET-1) was meansured after extraction from plasma of normal adults (5.9±1.9 pg/ml,n=22), normal children (7.1±1.86 pg/ml,n=29), nonhaemodialysed children with chronic renal failure (CRF) (11.1±1.8 pg/ml),n=10), renal graft recipients (9.5±3.4 pg/ml,n=37), haemodialysed children 24 h after a haemodialysis session (20.02±10.9 pg/ml,n=26) and haemodialysed children before and after a haemodialysis session (15.31±10.6 and 13.8±8.5 respectively,n=14). A sensitive and specific radioimmunoassay was used. ET-1 was significantly higher in non-haemodialysed CRF children and in renal graft recipients than in normal children (P<0.001 andP<0.01, respectively) and significantly higher in haemodialysed children when compared with normal children, non-haemodialysed CRF children and renal graft recipients (P<0.001). ET-1 concentrations were similar in normal children and normal adults. ET-1 was inversely correlated with glomerular filtration rate in non-haemodialysed CRF children (r=–0.39,P<0.01) and positively correlated with extracellular volume in haemodialysed children (r=0.435,P<0.03). After haemodialysis, ET-1 increased in 6 and decreased in 8 of the 14 children studied before and after a haemodialysis session.     

Evaluation of a new generation of plastic evacuated blood-collection tubes in clinical chemistry, therapeutic drug monitoring, hormone and trace metal analysis.

Polyethylene terephthalate (PET) tubes have several advantages over glass tubes: they are unbreakable, lighter and more easily disposed of. Despite a steady increase in their use and an expansion of the range of available tubes, few studies validating their use have been published in the literature. This paper describes the various studies that have been performed to compare VENOJECT glass, VENOSAFE PET and VENOSAFE PET/heparin tubes for the assay of a panel of analytes in routine clinical chemistry, immunochemistry, hormone and tumor marker analysis and trace metal determination. These studies demonstrate that VENOSAFE PET tubes are a suitable alternative to glass tubes.     

Use of health care services for psychological distress by immigrants in an urban multicultural milieu.

OBJECTIVE: Research in the United States tends to attribute low rates of use of mental health services by immigrants to economic barriers. The purpose of our study was to examine this issue in the context of Canada's universal health care system. METHODS: A survey of the catchment area of a comprehensive clinic in Montreal interviewed random samples of 924 Canadian-born individuals and 776 immigrants born in the Caribbean (n = 264), Vietnam (n = 234), or the Philippines (n = 278) to assess their health care use for somatic symptoms, psychological distress, and recent life events. RESULTS: Overall rates of use of medical services in the past year were similar in immigrant (78.5%) and nonimmigrant (76.5%) groups. Rates of use of health care services for psychological distress were significantly lower among immigrants (5.5% compared with 14.7%, P < 0.001). This difference was attributable both to a lower rate of use of specialty mental health services by immigrants (2.5% compared with 11.7%, P < 0.001) and to differential use of medical services for psychological distress (3.5% compared with 5.8%, P = 0.02). When level of psychological distress was controlled, Vietnamese and Filipino immigrants were one-third as likely as Canadian-born residents to make use of mental health services. The lower rate of use by immigrants could not be explained by differences in sociodemographics, somatic or psychological symptoms, length of stay in Canada, or use of alternative sources of help. CONCLUSION: Immigrant status is associated with lower rates of use of mental health services, even with universal health insurance. This lower rate of use likely reflects cultural and linguistic barriers to care.     

Upregulation of CD40, CD80, CD83 or CD86 on alveolar macrophages after lung transplantation.

BACKGROUND: Alveolar macrophages (AMs) are known to be poor antigen-presenting cells, and lack the accessory molecules such as CD40, CD80 or CD86 to activate T cells. The question raised is about the potential changes in phenotypes after lung transplantation, particularly during acute rejection episodes. METHODS: The present study analyzed the phenotype of AMs longitudinally in 45 lung transplant patients, between August 1997 and April 2002, with a follow-up period of 27.2 +/- 2.5 (mean +/- SEM) months. There were 7.7 +/- 0.6 bronchoalveolar lavage (BAL) assessments performed per patient (i.e., 345 BALs), simultaneously with transbronchial biopsies. Transplantation was soon followed by a progressive upregulation of CD40 on 49.7 +/- 8% of AMs during the first month, and this marker remained elevated at 60 +/- 8% after 5 years. RESULTS: Both CD86 and CD80, as well as CD83, a marker of dendritic cells, were enhanced for most AMs during Grade A2 and A3 rejection episodes. A correlation was found between expression of CD83 and CD86, but not between CD1a and CD86. Immunohistology confirmed that CD40-positive cells in the alveoli corresponded to AMs and to some dendritic cells in the basal layers of the airways. In vitro studies showed that harvested AMs with these enhanced accessory molecules remained poor stimulators of allogeneic cells, a phenomenon that may be related to the ongoing immunosuppressive treatments. CONCLUSIONS: AM phenotypes showed marked changes during early or late acute rejection episodes, acquiring CD80, CD83 and CD86, while CD40 expression was further enhanced. This finding may provide clues on how to monitor the tolerance of transplanted lungs and may also provide new insights into the pathophysiology of lung transplantation.     

Inflammatory reaction in progressive multifocal leukoencephalopathy: Harmful or beneficial?

Progressive multifocal leukoencephalopathy (PML) occurs in patients with profound immunosuppression. Although lesions are usually devoid of lymphoplasmocytic infiltrates, inflammatory forms of PML have been described, in both human immunodeficiency virus (HIV)-seropositive (HIV+) and-seronegative (HIV?) patients. In addition, PML has been shown to develop in HIV+ patients shortly after introduction of highly active antiretroviral therapy (HAART), despite a recovery of the immune system. Therefore, one could postulate that PML might arise in the context of an immune reconstitution syndrome. To examine the clinical and neuroradiological characteristics of inflammatory forms of PML, the authors performed a retrospective analysis of the patients seen at their institution since 1996 as well as a review of the literature. Of 39 HIV+ and HIV?PML patients, 5 (13%) presented with an inflammatory form of this disease. Two HIV+ patients developed PML soon after the onset of HAART, concomitant to immune recovery, as demonstrated by a decrease of HIV viral load (VL) and an increase of CD4+ T-cell count. Three patients (2 HIV+ and 1 HIV?) had signs of inflammation in the central nervous system (CNS) characterized by contrast-enhancing lesions on neuroimaging studies, and/or inflammatory infiltrates on brain biopsy. The presence of JC virus-specific cytotoxic T lymphocytes was demonstrated in 4/4 patients tested and the outcome was favorable in 3 of them. In agreement with previously published case reports, the data indicate that inflammatory reactions in PML are not infrequent, and that they are generally associated with a favorable prognosis. Therefore clinicians should not disregard the diagnosis of PML in presence of contrast-enhancing brain lesions, and should use caution before treating these immunosuppressed individuals with steroids.     

A multicentre double-blind comparison of hydroxyzine, buspirone and placebo in patients with generalized anxiety disorder

The efficacy of hydroxyzine and buspirone, controlled by placebo, was investigated in a double-blind, parallel group, multicentre study conducted in France and the UK. A total of 244 patients with generalised anxiety disorder in primary care was allocated randomly to treatments with hydroxyzine (12.5 mg morning and mid-day, 25 mg evening), buspirone (5 mg morning and mid-day, 10 mg evening) or placebo (three capsules/day) for 4 weeks, preceded by a 1-week single-blind placebo run-in and followed by 1-week single-blind placebo administration. Rating scales were applied on days -7,0,7,14,12,28 and 35. Seventy percent of the patients were female; the average age was 41 ± 11 years, and the mean Hamilton Anxiety Score at day 0 was 26.5 ± 4.2. Only 31 of the 244 patients dropped out, but equally in the three groups. Intention-to-treat LOCF analyses on the primary variable showed a significant difference only between hydroxyzine and placebo with respect to improvement on the Hamilton Anxiety Scale (10.75 versus 7.23 points, respectively). Secondary variables such as CGI and self-ratings (HAD scale) showed both hydroxyzine and buspirone to be more efficacious than placebo. Thus, hydroxyzine is a useful treatment for GAD. Received: 26 January 1998/Final version: 15 May 1998