Lymphadenopathies in human immunodeficiency virus infection

This article describes the various non-neoplastic lymphadenopathies that occur in patients infected with the human immunodeficiency virus (HIV), before or during the stage of acquired immunodeficiency syndrome (AIDS). The stages that develop during the HIV infection include: primary infection (acute infection, spread of the virus, development of host immune response, and acute retroviral syndrome), chronic infection or clinical latency, and finally, the AIDS stage. Non-neoplastic lymphadenopathies can occur at any of these phases of the infection and are due to multiple causes that can be divided into infectious causes (bacterial, fungal, parasitic, viral), and reactive causes (persistent generalized lymphadenopathy and a variety of situations that they also occur in immunocompetent people such as Castleman's disease and Kikuchi-Fujimoto's disease, among others). The general, histological and immunophenotypic characteristics of these pathologies are described.     

Nocardial infection in patients infected with the human immunodeficiency virus

During the period 1981–2000, we diagnosed eight cases of HIV– Nocardia co-infection (0.38% of AIDS cases). Six were males, and the mean age was 28.6 years. The most common risk factor for HIV infection was intravenous drug abuse. Most patients were severely immunodepressed at the time of diagnosis (mean CD4⁺ count, 35 cells/µL). The clinical forms of nocardiosis seen were pulmonary infection in three, skin or soft tissue infection in three, disseminated in one, and pulmonary colonization in one. Most patients were given sulfonamides, and a clinical response was observed in six of seven treated patients. However, two patients with pulmonary disease died from progressive infection. Although its incidence is very low among AIDS patients, nocardiosis is associated with high morbidity and mortality among HIV-infected individuals.     

Lower cognitive reserve in the aging human immunodeficiency virus-infected brain

More HIV-infected individuals are living longer; however, how their brain function is affected by aging is not well understood. One hundred twenty-two men (56 seronegative control [SN] subjects, 37 HIV subjects with normal cognition [HIV+NC], 29 with HIV-associated neurocognitive disorder [HAND]) performed neuropsychological tests and had acceptable functional magnetic resonance imaging scans at 3 Tesla during tasks with increasing attentional load. With older age, SN and HIV+NC subjects showed increased activation in the left posterior (reserve, “bottom-up”) attention network for low attentional-load tasks, and further increased activation in the left posterior and anterior (“top-down”) attention network on intermediate (HIV+NC only) and high attentional-load tasks. HAND subjects had only age-dependent decreases in activation. Age-dependent changes in brain activation differed between the 3 groups, primarily in the left frontal regions (despite similar brain atrophy). HIV and aging act synergistically or interactively to exacerbate brain activation abnormalities in different brain regions, suggestive of a neuroadaptive mechanism in the attention network to compensate for declined neural efficiency. While the SN and HIV+NC subjects compensated for their declining attention with age by using reserve and “top-down” attentional networks, older HAND subjects were unable to compensate which resulted in cognitive decline.     

Alimentary tract cytopathology in human immunodeficiency virus infection: a review of experience in Los Angeles

In the past decade, over 100,000 cases of the acquired immunodeficiency syndrome (AIDS) have been reported in the United States. Conservative estimates suggest that 1.5 million people are infected with the human immunodeficiency virus (HIV), the etiologic agent of AIDS. Major metropolitan areas, such as Los Angeles, have experienced a rapid increase in the number of AIDS cases. At the Los Angeles County-University of Southern California Medical Center, we have gained significant insight into the cytologic findings associated with HIV infection. Based on our experience, we herein review the technical and morphologic evaluation of alimentary tract cytology specimens from this patient population.     

A review on brain structures segmentation in magnetic resonance imaging

Background and objectivesAutomatic brain structures segmentation in magnetic resonance images has been widely investigated in recent years with the goal of helping diagnosis and patient follow-up in different brain diseases. Here, we present a review of the state-of-the-art of automatic methods available in the literature ranging from structure specific segmentation methods to whole brain parcellation approaches.MethodsWe divide first the algorithms according to their target structures and then we propose a general classification based on their segmentation strategy, which includes atlas-based, learning-based, deformable, region-based and hybrid methods. We further discuss each category's strengths and weaknesses and analyze its performance in segmenting different brain structures providing a qualitative and quantitative comparison.ResultsWe compare the results of the analyzed works for the following brain structures: hippocampus, thalamus, caudate nucleus, putamen, pallidum, amygdala, accumbens, lateral ventricles, and brainstem. The structures on which more works have focused on are the hippocampus and the caudate nucleus. In general, the accumbens (0.69 mean DSC) is the most difficult structure to segment whereas the structures that seem to get the best results are the brainstem, closely followed by the thalamus and the putamen with 0.88, 0.87 and 0.86 mean DSC, respectively. Atlas-based approaches achieve good results when segmenting the hippocampus (DSC between 0.75 and 0.90), thalamus (0.88–0.92) and lateral ventricles (0.83–0.93), while deformable methods perform good for caudate nucleus (0.84–0.91) and putamen segmentation (0.86–0.89).ConclusionsThere is not yet a single automatic segmentation approach that can emerge as a standard for the clinical practice, providing accurate brain structures segmentation. Future trends need to focus on combining multi-atlas methods with learning-based or deformable approaches. Employing atlases to provide spatial robustness and modeling the structures appearance with supervised classifiers or Active Appearance Models could lead to improved segmentation results.     

Ischaemic preconditioning in the rat brain: a longitudinal magnetic resonance imaging (MRI) study

Ischaemic preconditioning in rats was studied using MRI. Ischaemic preconditioning was induced, using an intraluminal filament method, by 30 min middle cerebral artery occlusion (MCAO), and imaged 24 h later. The secondary insult of 100 min MCAO was induced 3 days following preconditioning and imaged 24 and 72 h later. Twenty-four hours following ischaemic preconditioning most rats showed small sub-cortical hyperintense regions not seen in sham-preconditioned rats. Twenty-four hours and 72 h following the secondary insult preconditioned animals showed significantly smaller lesions (24 h = 112 +/- 31 mm(3), mean +/- standard error; 72 h = 80 +/- 35 mm(3)), which were confined to the striatum, than controls (24 h = 234 +/- 32 mm(3), p = 0.026; 72 h = 275 +/- 37 mm(3), p = 0.003). In addition during lesion maturation from 24 to 72 h post-secondary MCAO, preconditioned rats displayed an average reduction in lesion size as measured by MRI whereas sham-preconditioned rats displayed increases in lesion size; this is the first report of such differential lesion volume evolution in cerebral ischaemic preconditioning. Copyright -Copyright 2001 John Wiley & Sons, Ltd.     

Functional magnetic resonance imaging of the human brain: data acquisition and analysis

It is now feasible to create spatial maps of activity in the human brain completely non-invasively using magnetic resonance imaging. Magnetic resonance imaging (MRI) images in which the spin magnetization is refocussed by gradient switching are sensitive to local changes in magnetic susceptibility, which can occur when the oxygenation state of blood changes. Cortical neural activity causes increases in blood flow, which usually result in changes in blood oxygenation. Hence changes of image intensity can be observed, given rise to the so-called Blood Oxygenation Level Dependent (BOLD) contrast technique. Use of echo-planar imaging methods (EPI) allows the monitoring over the entire brain of such changes in real time. A temporal resolution of 1–3 s, and a spatial resolution of 2 mm in-plane, can thus be obtained. Generally in a brain mapping experiment hundred of brain image volumes are acquired at repeat times of 1–6 s, while brain tasks are performed. The data are transformed into statistical maps of image difference, using the technique known as statistical parametric mapping (SPM). This method, based on robust multilinear regression techniques, has become the method of reference for analysis of positron emission tomography (PET) image data. The special characteristics of functional MRI data require some modification of SPM algorithms and strategies, and the MRI data must be gaussianized in time and space to conform to the assumptions of the statistics of Gaussian random fields. The steps of analysis comprise: removal of head movement effects, spatial smoothing, and statistical interference, which includes temporal smoothing and removal by fitting of temporal variations slower than the experimental paradigm. By these means, activation maps can be generated with great flexibility and statistical power, giving probability estimates for activated brain regions based on intensity or spatial extent, or both combined. Recent studies have shown that patterns of activation obtained in human brain for a given stimulus are independent of the order and spatial orientation with which MRI images are acquired, and hence that inflow effects are not important for EPI data with a TR much longer than T1.     

Functional mapping of color processing by magnetic resonance imaging of responses to selective P- and M-pathway stimulation

Magnetic resonance imaging sensitized to activity-related changes in cerebral blood oxygenation was performed to map responses to selective stimulation of the parvo- and magnocellular visual pathways in calcarine and adjacent ventral occipital cortex of human subjects. In a repetitive stimulation protocol isoluminant chromatic or isochromatic luminance modulation was alternated with steady light of the same mean chromaticity and luminance as a reference condition. While no significant effects were observed for diffuse luminance modulation, two consistent cortical foci responded to isoluminant chromatic stimulation. A strong response was obtained in calcarine cortex at both 2 and 10 Hz, and even for selective S-cone stimulation. A second weaker colorsensitive response was seen bilaterally in the collateral sulcus. Thus, the data not only confirm color-sensitive activation in the collateral sulcus elicited in previous studies by selective cognitive tasks, but additionally demonstrate color-sensitive activation in primary visual cortex. With stimuli defined according to electrophysiological response properties of early visual processing stages, this study complements phenomenological or cognitive approaches in functional mapping of the human visual system.     

Synthetic env gp41 peptide as a sensitive and specific diagnostic reagent in different stages of human immunodeficiency virus type 1 infection

An enzyme immunoassay (EIA) for serum antibodies to human immunodeficiency virus type 1 (HIV-1), based on the synthetic pentadecapeptide SGKLICT-TAVPWNAS, a segment of the transmembrane glycoprotein (gp41) of the virus, was developed and tested for sensitivity and specificity. Sera of 152 individuals at various stages of HIV-1 infection, including two prospectively and six retrospectively studied patients exposed to HIV-1 but seronegative on initial testing in whole-virus EIA and immunoblotting, were screened with the gp41 peptide antibody EIA. The reference population consisted of 1,000 healthy HIV-1 antibody-negative blood donors. In addition, five individuals with antibodies to HIV-2 were studied. Antibodies to the synthetic peptide were detected in 100% of those with asymptomatic infection. Only one patient with LAS failed to react in the peptide EIA. Patients with HIV-2 infection did not react in this test. The peptide antibodies appeared rapidly after infection, were detectable at the time when seroconversion was observed by immunoblotting, and preceded reactivity in whole-virus EIA. Sera of seven patients with verified HIV-1 infection did not react with gp41 in immunoblotting, although antibodies were readily detectable in the gp41 peptide EIA.     

眶内眼神经的断层解剖与MRI的对照研究

目的为眶内手术及MRI诊断提供解剖学基础。方法采用成人尸头6例(12侧)制成0.5mm的火棉胶连续切片;再选择健康志愿者15例(30侧)行MRI的水平位、冠状位扫描,对额神经、鼻睫神经和泪腺神经位置、走行和毗邻进行观察和识别,并与相应活体MRI图像对照研究。结果眶内眼神经的分支额神经、鼻睫神经和泪腺神经均经过眶上裂入眶;额神经发出眶上神经内外支和滑车上神经,鼻睫神经与眼动脉伴行,泪腺神经在外直肌上方前行。活体MRI眶内眼神经扫描,T1WI、T2WI及其各脂抑加权像上眶内眼神经呈中等信号。结论MRI检查时,宜选择水平位观察额神经并显示最佳,选择冠状位观察鼻睫神经及泪腺神经,鼻睫神经显示尚可,泪腺神经显示不清;与MRI对应的火棉胶连续切片能准确显示眶内眼神经的分支、走形,且其制备技术是研究眶内眼神经的一种简单、经济、切实、可行的方法。     

Functional and structural aging of the speech sensorimotor neural system: functional magnetic resonance imaging evidence

The ability to perceive and produce speech undergoes important changes in late adulthood. The goal of the present study was to characterize functional and structural age-related differences in the cortical network that support speech perception and production, using magnetic resonance imaging, as well as the relationship between functional and structural age-related changes occurring in this network. We asked young and older adults to observe videos of a speaker producing single words (perception), and to observe and repeat the words produced (production). Results show a widespread bilateral network of brain activation for Perception and Production that was not correlated with age. In addition, several regions did show age-related change (auditory cortex, planum temporale, superior temporal sulcus, premotor cortices, SMA-proper). Examination of the relationship between brain signal and regional and global gray matter volume and cortical thickness revealed a complex set of relationships between structure and function, with some regions showing a relationship between structure and function and some not. The present results provide novel findings about the neurobiology of aging and verbal communication.     

Special anniversary review: twenty-five years of human immunodeficiency virus research: successes and challenges

During 25 years of research since HIV-1 was first identified in Paris, there have been great advances in our understanding of the virus and of the immune system. Practical advances include the early development of diagnostic tests of infection that made blood donation safe, and since 1996, combination anti-retroviral therapy that has great reduced incidence of AIDS in HIV-infected people who have access to the drugs. HIV prevention through behavioural change has been successful, and we do not yet have any safe and efficacious microbicides or vaccines.     

Reduced subcortical brain volumes in nonpsychotic siblings of schizophrenic patients: A pilot magnetic resonance imaging study

Substantial evidence suggests that nonpsychotic relatives of schizophrenia patients manifest subtle abnormalities in communication, eye movements, event-related potentials, and neuropsychological processes of attention, reasoning, and memory. We sought to determine whether adult relatives without psychosis or schizophrenia spectrum diagnoses might also have structural brain abnormalities, particularly in subcortical regions found to be impaired in patients with schizophrenia itself. Subjects were six sisters of schizophrenic patients and eleven normal female controls. Sixty contiguous 3 mm coronal, T1-weighted 3D magnetic resonance images (MRI) of the entire brain were acquired on a 1.5 Tesla magnet. Cortical and subcortical gray and white matter was segmented using a semiautomated intensity contour mapping algorithm. Volumes were adjusted for total brain volumes. Adjusted gray matter subcortical volumes were significantly smaller in relatives than in controls in total hippocampus, right amygdala, right putamen, left thalamus, and brainstem. Relatives had significantly enlarged left and total inferior lateral ventricles. These results, though preliminary, suggest that some never-psychotic relatives of schizophrenic patients have abnormal brain structure. If replicated in a larger sample including both sexes, these results would suggest that the genetic liability to schizophrenia is also expressed as structural brain abnormalities. Am. J. Med. Genet. 74:507–514, 1997. © 1997 Wiley-Liss, Inc.     

Clinical features of acute human immunodeficiency virus infection in Taiwan: A multicenter study

Background/purposeAcute HIV infection is characterized by a high concentration of HIV RNA in the plasma and rapid depletion of the CD4 cell count. This multicenter, retrospective observational study aimed to characterize the manifestations of acuteHIV infection in Taiwan.MethodsBetween 1 January 2012 and 31 December 2016, all patients aged 20 years or greater who presented with acute HIV infection were included. Demographic and clinical characteristics of the patients at diagnosis were collected. Baseline laboratory assessment included hemogram, CD4 count, plasma HIV RNA load (PVL), serologic markers of syphilis and hepatitis A, B, and C viruses, and serum biochemistry.ResultsThe proportion of acute HIV infection was 6.9% among the patients with newly diagnosed HIV infection during the study period. The most common presenting symptoms of acute HIV infection were fever, fatigue, and myalgia. The median PVL at diagnosis was 5.9 log₁₀ copies/ml, and median CD4 count was 307 cells/mm³. A total of 68 patients (27%) had baseline CD4 count less than 200 cells/mm³. Multiple logistic regression analysis, showed that the baseline CD4 count (OR, 4.02; p = 0.013) and aspartate aminotransaminase levels (OR, 3.49; p = 0.002) were associated with high PVL (>5 log₁₀ copies/ml); and high baseline PVL (OR, 2.64; p = 0.002) was associated with symptomatic acute HIV infection.ConclusionsManifestations of acute HIV infection are nonspecific and of wide spectrum ranging from fever to severe illness. A higher proportion of patients with initial CD4 counts of 200 cells/mm³ or less during acute HIV infection warrants early, timely diagnosis and treatment to prevent rapid disease progression.     

High levels of Epstein-Barr virus in the oropharynx: a predictor of disease progression in human immunodeficiency virus infection

The role of Epstein-Barr virus (EBV) on the progression of human immunodeficiency virus (HIV) infection is not well defined. The objective of this prospective study was to determine the prevalence of EBV excretion and the role that EBV might have on HIV disease progression. Fifty-two homosexual males were studied, all of whom had positive EBV serology. Twenty-four of the 27 HIV-seropositive and 14 of the 25 HIV-seronegative subjects had detectable levels of EBV DNA in oropharyngeal cells. In addition to a greater prevalence of detectable EBV, the level of excretion was higher among HIV-seropositives than among HIV-seronegatives, and higher among group III than among group II HIV-seropositive men. These results are consistent with earlier studies showing a relationship between immunosuppression and EBV reactivation. The EBV excretion levels in a control group of 52 age-matched heterosexual males were substantially lower than those found in the homosexual group. In a proportional hazards regression analysis EBV excretion was found to be the best single predictor of progression of HIV infection (P less than 0.001). HIV p24 core antigenemia (P = 0.048) and low EBNA (P = 0.024) were significant predictors independent of EBV excretion. Whether EV directly accelerates the time to progression or is merely a marker of underlying subclinical immunosuppression remains an open question.     

Normal diameter of the thoracic aorta in adults: a magnetic resonance imaging study

To determine the evolution of the diameter of the thoracic aorta with age in order to detect dilatation more reliably by imaging, we performed a retrospective analysis of the MRI examinations of the normal thoracic aorta of 66 subjects aged 44.1±19.1 years (range 19.1–82.4 years) obtained between 1991 and 2000 on a Magnetom SP 42 1T apparatus (Siemens) using T1-weighted spin echo sequences with electrocardiographic synchronization. Sixteen measurements were made in the axial plane, the oblique sagittal plane in the axis of the aortic arch, and the oblique frontal plane perpendicular to the latter at the level of the ascending aorta, the arch and the descending thoracic aorta. We found an increase in the thoracic aorta diameter and a significant relationship between this diameter and the age of our subjects, wherever the measure was performed. However, there was no systematic correlation between aortic diameter and age. The aortic diameter evolved with age and a marked difference seemed to exist in measurements made in groups younger and older than 40 years. This study, conducted on a small population of 66 patients, thus helps to define a normal aortic diameter, thereby making the diagnosis of pathological dilatation of the aorta more reliable.

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Diamètre normal de l'aorte thoracique chez l'adulte. Etude en imagerie par résonance magnétique

Résumé Pour déterminer l'évolution du diamètre de l'aorte thoracique en fonction de l'âge afin de pouvoir juger d'une éventuelle dilatation sur les examens d'imagerie, les auteurs ont analysé rétrospectivement des Imageries par Résonance Magnétique d'aortes thoraciques normales de 66 sujets âgés de 44,1±19,1 ans (19,1 à 82,4 ans) réalisés de 1991 à 2000 sur un appareillage Magnetom SP 42 de 1 T (Siemens, Erlangen) en séquences de spin écho pondérées en T1 avec synchronisation à l'électrocardiogramme; 16 mesures étaient effectuées dans les plans transversal, sagittal oblique dans l'axe de l'arc de l'aorte, et frontal oblique perpendiculaire au précédent au niveau de l'aorte ascendante, l'arc de l'aorte et l'aorte thoracique descendante. Il existait un accroissement significatif du diamètre de l'aorte sur les mesures effectuées en fonction de l'âge. En revanche il n'existait pas de corrélation systématique entre diamètre aortique et âge. Le diamètre aortique évoluait en fonction de l'âge de manière significative avec une différence qui paraissait nette entre la cohorte des sujets de moins de 40 ans celle des patients de plus de 40 ans. Cette étude, effectuée sur une courte série de 66 patients, permet donc d'approcher le diamètre aortique normal et d'aider au diagnostic de dilatation pathologique de l'aorte.

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