Advanced Technology Laboratories Research Articles

Lite Image Analysis Module Salivary Diagnostic Tool - A Review

Background: Saliva is a versatile biofluid that can help in detecting any oral or systemic disease of an individual. Saliva seems to be clinically an informative biofluid for easy prognosis of a disease and clinical or laboratory diagnosis of oral as well as many systemic diseases. It has some specific soluble biological markers that can be considered as an ideal approach for early detection of diseases.
 Aim: The aim of this paper was to review the recent developments of the Lite Image Analysis Module.
 Conclusion: Thus, this technology primarily helps in a rapid assessment of salivary biomarker levels signifying the probable systemic and oral condition of an individual both in quantitative as well as qualitative manner. Adopting a simple and quick technique, LIAM can be used effortlessly in some rural remote areas as well where advanced high technology laboratories have not yet reached.
 Clinical Significance: It is one of the recent advancements in the world of salivary diagnosis LIAM (Lite Image Analysis Module) that is a portable, light, hand-held scanning device which magnificently integrates a distinct analyte identification system that detects the type of analytes being tested and transfer the report straight to a smartphone or a Bluetooth devices.

EEG & Eye-Tracking Changes With Expertise In A Multi-Vehicle Control Task

EEG & Eye-Tracking Changes With Expertise In A Multi-Vehicle Control Task

Minimum-time open-loop and closed-loop optimal guidance with GA-PSO and neural fuzzy for Samarai MAV flight

Nonmilitary applications of unmanned air vehicles (UAVs), especially as rescue vehicles to obtain information have increased in recent years. Small UAVs (SUAV) were used in nonmilitary projects, where the focus was on autonomous vehicles; however, microaerial vehicles (MAVs), such as Samarai, make use of radio control, and they were not autonomous vehicles [1]. Autonomous UAVs need sophisticated guidance, control, and navigation systems with conventional aircraft flying processes. Most of current UAVs use ground-station commands for guidance purposes, although autonomous UAVs tend to reduce dependency on ground-station command via autonomous algorithms, such as intelligent methods. Therefore, ground-based air control may not suffice to cover every flying mission. Thus, self-contained, onboard guidance via intelligent methods, such as fuzzy logic, has been considered to achieve this goal. Lockheed Martin’s Intelligent Robotics Laboratory has spent the last 5 years developing an unmanned craft to replicate the air vehicle motion. The idea was based on the motion of maple seed, which whirls softly to the ground after dropping from maple tree. This motion, which is similar to a one-winged helicopter, inspired Lockheed Martin to design a new type of flying vehicles, beneficial in military and nonmilitary surveillance. Maple seeds disperse themselves by auto-rotating passively by using a single wing as they descend from trees, thereby ensuring they are widely scattered. Inspired by these flight concepts, Lockheed Martin Advanced Technology Laboratories developed the Samarai MAV, a 30-cm-radius maple seedlike aircraft that can take off and land vertically and fly laterally, like a helicopter, due to the intrinsic stability of the maple seeds’ nature [2] (Figure 1).

A scare in the OR highlights value of systems engineering.

A scare in the OR highlights value of systems engineering.

Advancing Robotics: The Urban Challenge Effect

The Defense Advanced Research Project Agency’s (DARPA) Urban Challenge, a contest that pitted robots against each other for 6 h without human intervention, was aimed at advancing the state-of-the-art in research for perception, planning, sensors, and situational awareness with the goal of military application. The event was a success, gaining national media attention for DARPA and robotics; but how well did DARPA succeed in advancing research for the military? To answer this question, a number of post-event activities conducted by Lockheed Martin Advanced Technology Laboratories, a participating member of the Ben Franklin Racing Team, will be presented and examined. In addition, a comparison of requirements between the Urban Challenge contest and current military applications will be conducted. I. Introduction I T is rare to be both a part of history and to write it.That is what we attempt to accomplish at the DefenseAdvanced Research Project Agency (DARPA) Urban Challenge. This paper pulls ourselves back for a moment and tries to view the field from afar, seeing from whence we have come and anticipating where we will go. DARPA’s Grand Challenges have become a large part of robotic history. At the same time, there is a congressional mandate that sets a goal for the future that a third of all ground vehicles in the military be robotic. How far have we come and how far do we have yet to go? Answering these questions is the focus of this material. The Urban Challenge (Fig. 1) was DARPA’s third Grand Challenge—a contest that pitted robotic vehicles against each other in a simulated urban environment. The final event included 11 robotic vehicles and their DARPA chase cars, along with 50 manned vehicles that were used to simulate various traffic situations. All robotics vehicles were required to be completely autonomous and team members were not allowed on the course while the vehicles were running. The contest was both a race, with a maximum time limit of 6h, and a “driver’s test” for the autonomous vehicles that evaluated their skill in executing maneuvers that a typical human driver would encounter on populated city streets. For brevity, we will not list all the requirements for the Urban Challenge. In summary, the Urban Challenge required vehicles to detect roads, lanes, and other vehicles; perform left, right, and U turns; pull in and out of parking spaces; merge into traffic; change lanes in traffic; queue up in line at traffic stops; understand and follow intersection precedence;andavoidcollisionsatalltimes[1,2].Ingeneral,DARPArequiredallvehiclestoobeyCaliforniadriving laws and be safe at all times while performing missions over a 60 mile course in under 6h [3]. This set of requirements was vastly different from previous Grand Challenges, and arguably more challenging, owing to the focus on interaction with other vehicles. Previous installments in the Grand Challenge were primarily

FLOODED OUT OF THEIR LABS

ON WEDNESDAY, June 11, University of Iowa officials ordered faculty in the Iowa Advanced Technology Laboratories (IATL) to evacuate their labs and offices. The Iowa River, which bisects the university campus, was rising quickly after a week of heavy rainstorms and was predicted to crest at 33 feet—about 11 feet above flood stage. The chemists, physicists, and engineers of IATL were told they had until 5 PM that Saturday to get out anything they wanted to protect. “At that point, they put tape all along the windows and doors to show how high the water could get,” says Vicki H. Grassian, a chemistry professor whose labs are in the building. “It was almost up to your neck.” It was a sobering demonstration. Faculty, staff, students, and postdocs began working together to move samples, equipment, and other essential items either from the first to second floor, or out of the building entirely. The researchers didn’t know ...

Premature atherosclerosis in patients with xanthelasma

Only about half the patients with xanthelasma are hyperlipidemic. The clinical significance of xanthelasma as a marker of cardiovascular disease is not yet well defined. To determine the risk of cardiovascular disease in patients with normolipidemic and hyperlipidemic xanthelasma. Carotid ultrasonography (7 MHz using B-mode images, Advanced Technology Laboratories) was used to detect carotid plaques and measure the intima-media thickness (IMT) of the common carotid arteries. Seventeen patients with normolipidemic and hyperlipidemic xanthelasma were examined and compared with 21 age-matched normal subjects. The risk of cardiovascular disease was significantly increased in patients with xanthelasma. Carotid plaques were more frequent in patients with xanthelasma than in controls (64.7% and 23.8%, respectively; P = 0.020), and IMT was significantly higher (mean +/- SD: 1.1 +/- 0.1 and 0.6 +/- 0.2 mm, respectively; P < 0.001). The difference of carotid IMT between normolipidemic xanthelasma and hyperlipidemic xanthelasma was not statistically different (mean +/- SD: 1.1 +/- 0.1 and 1.1 +/- 0.2 mm, respectively; P = 0.577). Premature carotid atherosclerosis is observed in patients with normolipidemic and hyperlipidemic xanthelasma. Patients with xanthelasma should be considered to have an increased risk of cardiovascular disease independently to the level of plasma lipids. A larger number of patients is, however, needed to confirm this preliminary study.

Age and Target Organ Damage in Essential Hypertension: Role of the Metabolic Syndrome

We sought to investigate the association of the metabolic syndrome (MS) with cardiovascular alterations in essential hypertensives in relation to age. A total of 3266 untreated and treated hypertensive patients categorized in three age groups (I: 17 to 40 years; II: 41 to 64 years; III: >64 years) were considered for this analysis. All patients underwent extensive investigations searching for target organ damage (TOD). The MS was defined according to Advanced Technology Laboratories (ATP) III criteria. In the entire population, the risk of left ventricular hypertrophy (LVH), carotid abnormalities, and microalbuminuria increased by 2.5 (P = .003), 2.2 (P = .005), and 1.5 times (P = .01), respectively, in the presence of MS after adjusting for several confounders. Prevalence of LVH (group I: 39% v 22%; group II: 53% v 35%; group III: 69% v 52%, P < .01 for all), carotid thickening (group I: 8% v 2%; group II 29% v 19%; group III: 69% v 52%, P < .05 for all) and microalbuminuria (group I: 20% v 11%; group II: 16% v 8%; group III: 18% v 11%, P </= .05 for all) was significantly higher in patients with MS than in their counterparts across all age groups. In hypertensive patients the MS amplifies TOD regardless of patient's age, thus increasing cardiovascular risk. This synergistic effect may accelerate the early development of TOD in young hypertensives and enhance the age-associated cardiovascular alterations in the elderly.

3115: Ultrasonographic guided mammotome excisional biopsy for abdominal wall masses: A case report

Objectives: To introduce the usefulness of mammotome excisional biopsy for the soft tissue mass other than breast mass.Methods: A 37-year old man who had underwent oriental acupunctures on the abdominal wall 4 years ago, presented three painful palpable masses on previous acupuncture sites since 3 months ago. The largest one measuring as about 1.5 cm in diameter at the suprapubic area was surgically excised but recurrent abscess and seroma were developed at operation site. The two smaller masses measuring about 0.38× 0.25 cm and 0.38× 0.31 cm, respectively, were requested for mammotome excision (Biopsy Medical/Johnson and Johnson, Cincinnati, OH) under ultrasound (ATL(Advanced Technology Laboratories), Bothell, WA, HDI 5000) guidance.Results: Two painful small palpable lesions were successfully excised by mammotome with an 11 gauge probe under ultrasound guidance. Image-evident lesions were not visible after mammotome excision and the patient was satisfied with this procedure rather than surgical excision. On pathology, foreign body reaction with acute and chronic inflammation, eosinophic infiltration and fibrosis was found. Clinical recurrence or post-procedure complication such as hematoma or abscess formation did not occur.Conclusions: Mammotome excisional biopsy may be applicable to the soft tissue mass other than breast mass carefully. Objectives: To introduce the usefulness of mammotome excisional biopsy for the soft tissue mass other than breast mass. Methods: A 37-year old man who had underwent oriental acupunctures on the abdominal wall 4 years ago, presented three painful palpable masses on previous acupuncture sites since 3 months ago. The largest one measuring as about 1.5 cm in diameter at the suprapubic area was surgically excised but recurrent abscess and seroma were developed at operation site. The two smaller masses measuring about 0.38× 0.25 cm and 0.38× 0.31 cm, respectively, were requested for mammotome excision (Biopsy Medical/Johnson and Johnson, Cincinnati, OH) under ultrasound (ATL(Advanced Technology Laboratories), Bothell, WA, HDI 5000) guidance. Results: Two painful small palpable lesions were successfully excised by mammotome with an 11 gauge probe under ultrasound guidance. Image-evident lesions were not visible after mammotome excision and the patient was satisfied with this procedure rather than surgical excision. On pathology, foreign body reaction with acute and chronic inflammation, eosinophic infiltration and fibrosis was found. Clinical recurrence or post-procedure complication such as hematoma or abscess formation did not occur. Conclusions: Mammotome excisional biopsy may be applicable to the soft tissue mass other than breast mass carefully.

Evolutionary agent learning

Evolutionary Platform for Agent Learning (EPAL) is a novel methodology for agent learning, based on an extension to genetic programming that Lockheed Martin Advanced Technology Laboratories (LM ATL) developed. EPAL allows software agents to learn how to better operate under external conditions, so they do not repeat their mistakes. It creates both subtle and drastic changes to agent behavior. Subtle changes arise from learning task parameters; drastic changes emerge from learning improved workflows containing new programming constructs and tasks. Although EPAL was constructed for learning by LM ATL developed extendible mobile agent architecture agents, it is a suitable learning methodology for any software agent whose behavior can be represented as a workflow and further decomposed into building blocks, such as operators, tasks, and parameters. Our agents learned to solve a real-world problem that is similar to problems encountered in Navy Fleet Battle Experiment-Juliet. Results for both parameter learning and workflow learning are very encouraging.

Congenital lobar emphysema and increased nuchal translucency

Congenital lobar emphysema and increased nuchal translucency

Detection of Single Muscle Fiber Movements (Fibrations) in SMA Type I by High Resolution Ultrasound

Introduction: Movements of a group of muscle fibers innervated by a single motor unit (fasciculations) are detected by clinical inspection, electromyography and ultrasound. Up to now movements of single muscle fibers are realized just by electromyography and can be called fibrillations. We tried to analyze single muscle fibers by a new ultrasound technique and that was when we saw movements of single muscle fibers. Method: We examined three infants with spinal muscular atrophy (SMA) type I and typical deletion in the survival motor neuron (SMN) gene and ten children with other neuromuscular diseases by means of a high resolution ultrasound system (HDI 5000 and 15–7MHz-Compact-Linear-Broadband-Scanhead from Advanced Technology Laboratories, Washington, USA). Results: We found only in the three infants with SMA type I the well-known rhythmic and synchronous movements of groups of muscle fibers (fasciculations) as well as a turmoil of arrhythmic and asynchronous twitches of single muscle fibers. Conclusions: By means of high resolution ultrasound it was possible to detect movements of even single muscle fibers. The turmoil of single muscle fibers was very impressive. But we do not think the term fibrillations is right. Fibril is the diminutive form of fiber and myofibrils are the contractile filaments of muscle fibers. That is why we suggest the term fibrations. This term is derived from fiber, because we are not able to see movements of myofibrils but rather of single muscle fibers by the new ultrasound technique. Acknowledgements: We thank the local group of the German Society for Patients with Muscle Diseases (Deutsche Gesellschaft für Muskelkranke e.V.) in Elmshorn for financial support and we thank the departments for gynecology and pediopathology of Kiel University Hospital for technical support.

Duplex Ultrasound Imaging of Iliac Venous Stents

Postthrombotic syndrome (PTS) is characterized by persistent leg edema, discoloration, pain, and ulceration in patients with a history of a deep vein thrombosis (DVT). We describe a 60-year-old man who had unilateral PTS develop from an iliofemoral DVT. The patient was treated with thrombolytic therapy using reteplase (Retavase, Centocor, Malvern, PA) followed by mechanical thrombectomy. Percutaneous transluminal angioplasty of the common and external iliac veins was subsequently performed, and a total of six self-expanding nitinol stents were deployed. Stent patency was assessed using an Advanced Technology Laboratories HDI 5000 (Philips Ultrasound, Bothell, WA) ultrasound machine with a curved 5-2 MHz transducer. B-mode images and color duplex ultrasonography with Doppler signals were recorded. Intraluminal echoes and the lack of vein compressibility confirmed the presence of remote thrombus more distally. However, widely patent stents with spontaneous, phasic blood flow were demonstrated in the common and external iliac veins. The patient's edema significantly improved. Deployment of stents to maintain vessel patency of diseased iliac veins is being performed with increasing frequency. Duplex ultrasonography is an inexpensive, noninvasive modality that can be used to follow patients who have had an endovascular venous intervention.

Prospective controlled study of the natural history of asymptomatic 60% to 69% carotid stenosis according to ultrasonic plaque morphology

Background/Purpose: In spite of the conclusions of the Asymptomatic Carotid Atherosclerosis Study, some clinicians are still reluctant to recommend carotid endarterectomy (CEA) for patients with asymptomatic ≥60% carotid stenosis (ACS). This study analyzes the natural history of 60% to 69% ACS according to ultrasonic plaque morphology and its implication on treatment. Patient Population and Methods: During a 2-year period, patients with 60% to 69% ACS entered into a protocol of carotid duplex scan surveillance/clinical examination every 6 months. The ultrasonic plaque morphology was classified as heterogeneous (group A, n = 162) or homogeneous (group B, n = 229) with HDI 3000/HDI 5000 systems (Advanced Technology Laboratories, Bothwell, Wash). CEA was done if lesion progressed to ≥70% stenosis or became symptomatic. Results: Three hundred eighty-two patients (391 arteries) were followed for a mean interval of 37 months. The clinical/demographic characteristics were similar for both groups. The incidence rate of future ipsilateral strokes was significantly higher in group A than in group B: 13.6% versus 3.1% ( P = .0001; odds ratio [OR], 5). Similarly, the incidence rate of all neurologic events (stroke or transient ischemic attack [TIA]) was higher in group A than in group B: 27.8% versus 6.6% ( P = .0001; OR, 5.5). Progression to ≥70% stenosis was also higher in group A than in group B: 25.3% versus 6.1% ( P = .0001; OR, 5.2). Forty-four late CEAs (27.2%) were done in group A (16 for stroke, 21 for TIA, and seven for ≥70% ACS) versus 13 (5.7%) in group B (five for stroke, seven for TIA, and one for ≥70% ACS; P = .0001; OR, 6.2). Conclusion: Patients with 60% to 69% ACS with heterogeneous plaque had a higher incidence rate of late stroke, TIA, and progression to ≥70% stenosis than patients with homogeneous plaque. Prophylactic CEA for 60% to 69% ACS may be justified if associated with heterogeneous plaque. (J Vasc Surg 2002;36-437-42.)

Ultrasonographic Evaluation of Focal Hepatic Lesions : Comparison of Fundamental, Tissue Harmonic, Fundamental Compound and Harmonic Compound Imaging Techniques

Purpose: To compare the ultrasonographic image quality of fundamental imaging (FI), tissue harmonic imaging (THI), fundamental compound imaging (FCI), and harmonic compound imaging (HCI) in the evaluation of focal hepatic lesions. Materials and Methods: Ninety-four focal hepatic lesions (27 hemangiomas, 15 hepatocellular carcinomas, 14 metastases, and 38 cysts) in 74 patients [30 males and 44 females aged 33-82 (mean, 55) years] were included in our study. All patients underwent FI, THI, FCI, and HCI using an HDI 5000 Sono CT scanner (Advanced Technology Laboratories, Bothell, CA., U.S.A.) with a 2-5MHz convex transducer. Images were analysed by two abdominal radiologists who used a 4-point scale and reached a consensus. In the case of solid lesions, four parameters, as follows, were evaluated: lesion conspicuity, internal morphology, overall image quality, and peripheral halo. For cysts, three parameters (internal artifact, sharpness of margin, and posterior enhancement) were assessed. For statistical analysis, the Scheffe method (ANOVA test) was used. Results: For solid lesions (hemangioma, hepatocellular carcinoma, and metastasis), THI, FCI and HCI were superior to FI in terms of lesion conspicuity, internal morphology and overall image quality (p

Electron Beam CT in the Diagnosis of Recurrent Cardiac Lipoma

A 34-year-old woman had undergone resec-tion of a tumor infiltrating her left ventricle 13years earlier. The tumor was histologicallyclassified as a lipoma. After the operation, thepatient developed persistent ventricular ar-rhythmia with recurrent ventricular flutter thatnecessitated the insertion of an automatic im-plantable cardioverter–defibrillator. The chestradiograph obtained at that time showed bor-derline enlargement of the heart and a shoul-derlike widening of the cardiac silhouettetoward the left side (Fig. 1A). Multiplanartransesophageal echocardiography (SSA-270A; Toshiba, Tokyo, Japan) depicted an an-teroapical structure with an inhomogeneousechotexture. We performed transthoraciccontrast-enhanced echocardiography using10 mL of galactose palmitic acid–coated mi-crobubbles (4 g, 400 mg/mL, SHU 508A,Levoist; Schering, Berlin, Germany) withsecond harmonic imaging (HDI 3000cv; Ad-vanced Technology Laboratories, Bothell,WA). The resultant images showed a hypo-echoic nonenhancing epicardial tumor ex-tending into the myocardium of bothventricles (Fig. 1B). Because we suspectedthat the patient had recurrent cardiac lipoma,we performed electron beam CT (C150;Imatron, San Francisco, CA; ECG trigger-ing, single-slice mode, 3-mm slice thickness,3-mm table feed, 100-msec exposure time,IV bolus injection of contrast material) thatrevealed a tumor that had the density of fatnear the heart base at the left ventricle. Thetumor had a maximal extension of 5 × 3.5 cmand showed signs of infiltration into the apexand lateral wall of the left ventricle, the sep-tum, the right ventricular myocardium, andthe heart base (Figs. 1C–1F).

Detection of subclinical coronary atherosclerosis using two-dimensional, high-resolution transthoracic echocardiography

OBJECTIVESWe evaluated whether two-dimensional high-resolution transthoracic echocardiography (HR-2DTTE) can detect changes in arterial wall thickness and size associated with subclinical coronary artery disease (CAD).BACKGROUNDArterial wall thickening, compensatory arterial enlargement and a preserved arterial lumen characterize subclinical atherosclerosis. Detection of these changes during the asymptomatic stage of CAD may allow early treatment and prevention of acute coronary events.METHODSTwenty-six patients with angiographically proven CAD and 29 normal volunteers underwent HR-2DTTE evaluation of the left anterior descending coronary artery (LAD) using an ATL 5000 echograph (Advanced Technology Laboratories, Bothell, Washington) with a 4 to 7 MHz transducer. Significant (>70%) LAD stenosis was present in 15 patients (mean 82%); 11 patients did not have significant LAD stenosis (mean 26%) and represented a surrogate for subclinical LAD disease. Wall thickness, maximal luminal diameter and external diameter of the LAD were measured.RESULTSLeft anterior descending coronary artery wall thickness was larger in patients (1.9 ± 0.4 mm) than it was in volunteers (0.9 ± 0.1 mm, p < 0.001). The external diameter of the LAD was (6.0 ± 1.1 mm) in patients and (3.9 ± 0.7 mm) in volunteers (p < 0.001). Luminal diameter was 2.2 ± 0.5 mm in patients and 2.1 ± 0.6 mm in volunteers (p = NS). There was no difference in wall thickness (1.9 ± 0.4 mm vs. 2.0 ± 0.4 mm), luminal diameter (2.2 ± 0.5 mm vs. 2.2 ± 0.4 mm) and external diameter (5.9 ± 1.0 mm vs. 6.2 ± 1.2 mm) between the patients with <70% and >70% LAD stenosis.CONCLUSIONSLeft anterior descending coronary artery wall thickness and external diameter are significantly increased in patients with CAD as compared with normal subjects, and HR-2DTTE is sensitive enough to detect these differences. Wall thickness and external diameter are increased to the same extent in patients with obstructive and subclinical LAD disease.

HORNET: a packet-over-WDM multiple access metropolitan area ring network

Current metropolitan area networks (MANs) based on the SONET transport are not developing at the rate required to support the phenomenal increase in data traffic. To address the needs of future MANs, the Optical Communications Research Laboratory at Stanford University and Sprint Advanced Technology Laboratories are building HORNET (Hybrid Optoelectronic Ring NETwork). HORNET has a multiple access architecture, in which nodes access any WDM channel using a novel media access control protocol and fast tunable laser transmitters. HORNET transports data packets directly over the WDM ring, eliminating the SONET transport. This paper presents the HORNET architecture, the node design consisting of novel packet-over-WDM components, and the experimental testbed with results.

Experimental demonstration of a novel media access protocol for HORNET: a packet-over-WDM multiple-access MAN ring

As packet-based traffic in the metropolitan area network continues to exponentially increase, and as content and applications become more distributed, conventional metropolitan area networks fail to function efficiently. Sprint Advanced Technology Laboratories and Stanford University's Optical Communications Research Laboratory are developing a new network called HORNET (hybrid opto-electronic ring network), which is optimized for bursty, unpredictable, packet-based traffic patterns with distributed sources and destinations. HORNET uses fast tunable transmitters and a novel media access control scheme to realize a packet-over-WDM multiple-access ring architecture. The experimental demonstration of the novel media access control scheme is presented in this work.

Preservation of lymphocyte immunophenotype and proliferative responses in cryopreserved peripheral blood mononuclear cells from human immunodeficiency virus type 1-infected donors: implications for multicenter clinical trials. The ACTG Immunology Advanced Technology Laboratories.

Human immunodeficiency virus type 1 (HIV-1) infection results in impaired immune function that can be measured by changes in immunophenotypically defined lymphocyte subsets and other in vitro functional assays. These in vitro assays may also serve as early indicators of efficacy when new therapeutic strategies for HIV-1 infection are being evaluated. However, the use of in vitro assays of immune function in multicenter clinical trials has been hindered by their need to be performed on fresh specimens. We assessed the feasibility of using cryopreserved peripheral blood mononuclear cells (PBMC) for lymphocyte immunophenotyping and for lymphocyte proliferation at nine laboratories. In HIV-1-infected patients with moderate CD4(+) lymphocyte loss, the procedures of density gradient isolation, cryopreservation, and thawing of PBMC resulted in significant loss of CD19(+) B cells but no measurable loss of total T cells or CD4(+) or CD8(+) T cells. No significant changes were seen in CD28(-) CD95(+) lymphocytes after cell isolation and cryopreservation. However, small decreases in HLA-DR(+) CD38(+) lymphocytes and of CD45RA(+) CD62L(+) were observed within both the CD4(+) and CD8(+) subsets. Fewer than 10% of those specimens that showed positive PBMC proliferative responses to mitogens or microbial antigens lost their responsiveness after cryopreservation. These results support the feasibility of cryopreserving PBMC for immunophenotyping and functional testing in multicenter AIDS clinical trials. However, small changes in selected lymphocyte subsets that may occur after PBMC isolation and cryopreservation will need to be assessed and considered in the design of each clinical trial.