Quantum Vacuum Excitation of a Quasinormal Mode in an Analog Model of Black Hole Spacetime.

Vacuum quantum fluctuations near horizons are known to yield correlated emission by the Hawking effect. We use a driven-dissipative quantum fluid of microcavity polaritons as an analog model of a quantum field theory on a black-hole spacetime and numerically calculate correlated emission. We show that, in addition to the Hawking effect at the sonic horizon, quantum fluctuations may result in a sizable stationary excitation of a quasinormal mode of the field theory. Observable signatures of the excitation of the quasinormal mode are found in the spatial density fluctuations as well as in the spectrum of Hawking emission. This suggests an intrinsic fluctuation-driven mechanism leading to the quantum excitation of quasinormal modes on black hole spacetimes.

EXPRESSION OF MENIN IN THE HUMAN THYROID GLAND.

INTRODUCTION: The expression of menin in the thyroid gland has long been debated. Animal models with targeted inactivation of menin in the thyroid gland have shown that its inactivation might play a role in the progression to a more aggressive type of cancer. Human studies are conflicting, some have identified mutations in the MEN1 gene in a sub-type of oncocytic thyroid carcinomas, while others have not identified a higher prevalence of thyroid cancer in MEN1 patients. OBJECTIVE: To analyze the immunohistochemical expression of menin in different types of thyroid carcinomas. MATERIALS AND METHODS: 48 thyroid tumours (12 papillary thyroid carcinomas (PTC), 6 anaplastic thyroid carcinomas (ATC), 12 poorly differentiated thyroid carcinomas (PDTC), 5 medullary thyroid carcinomas (MTC), 5 oncocytic follicular carcinomas (OC), 3 oncocytic adenomas (OA) and 5 goiters (G)) were tested for nuclear expression of menin using an anti-menin antibody. The expression was considered positive, negative or decreased. RESULTS: The expression of menin was positive, identical to normal tissue, in 39 cases (81.25%). The expression was decreased (n=8) or absent (n=1) in 9 tumours (18.75% - 2 PTC, 5 PDTC, 2 OC) accounting for 42% (5/12) of the PDTC and 40% (2/5) of the OC. CONCLUSIONS: Our results show that the expression of menin is generally preserved in human thyroid carcinomas, but it can be decreased or absent in certain types of thyroid cancer. Further molecular studies are needed to evaluate to potential of menin protein in tumorigenesis.

O6-Methylguanine-DNA methyltransferase status in neuroendocrine tumours: prognostic relevance and association with response to alkylating agents.

BACKGROUND: O(6)-Methylguanine-DNA methyltransferase (MGMT) loss of expression has been suggested to be predictive of response to temozolomide in neuroendocrine tumours (NETs), but so far, only limited data are available. We evaluated the prognostic and predictive value of MGMT status, assessed by two molecular methods and immunohistochemistry, in a large series of NETs of different origins. METHODS: A total of 107 patients, including 53 treated by alkylants (temozolomide, dacarbazine or streptozotocin), were retrospectively studied. In each case, we used methyl-specific PCR (MS-PCR) and pyrosequencing for evaluation of promoter methylation and immunohistochemistry for evaluation of protein status. RESULTS: MGMT promoter methylation was detected in 12 out of 99 (12%) interpretable cases by MS-PCR and in 24 out of 99 (24%) by pyrosequencing. O(6)-Methylguanine-DNA methyltransferase loss of expression was observed in 29 out of 89 (33%) interpretable cases. Status of MGMT was not correlated with overall survival (OS) from diagnosis. Progression-free survival and OS from first alkylant use (temozolomide, dacarbazine and streptozotocin) were higher in patients with MGMT protein loss (respectively, 20.2 vs 7.6 months, P<0.001 and 105 vs 34 months, P=0.006) or MGMT promoter methylation assessed by pyrosequencing (respectively, 26.4 vs 10.8 months, P=0.002 and 77 vs 43 months, P=0.026). CONCLUSIONS: Our results suggest that MGMT status is associated with response to alkylant-based chemotherapy in NETs.

Feasibility of performing treadmill walking test for patients with peripheral arterial occlusive disease by the advanced practice nurses.

AIM: The treadmill walking test with post-exercise pressure measurement can be used as a diagnostic test and could classify peripheral arterial disease of the lower limbs. It can also exclude the diagnosis allowing to raise the possibility of differential diagnoses. In this study, we assessed the feasibility of performing treadmill test by advanced practice nurse to assess suspected lower extremity peripheral artery disease patients. DESIGN AND METHOD: This is a longitudinal monocentric study to assess the feasibility of a treadmill walking test performed by an advanced practice nurse. The primary endpoint was the number of tests performed during this period. The secondary objectives were to evaluate the reasons for requesting the test, the main results obtained in terms of the test's contribution and diagnoses, and patients' clinical characteristics. RESULTS: From February to May 2023, amongst 31 patients who underwent the treadmill walking test, 4 tests were able to rule out peripheral arterial disease and to detect differential diagnoses. For the remaining 27 patients, 4 had stage IIa of the Leriche classification, 23 had stage IIb, 2 of which were associated with a narrow lumbar spine. In contrast to the usual report, the APN's report on the walking test included an identification of cardiovascular risk factors, as well as a possible medical reorientation linked to the correction of a detected cardiovascular risk factor. CONCLUSION: The treadmill walking test can be performed by an advanced practice nurse. He/She added a comprehensive/global patient management, with the detection of cardiovascular risk factors. This new profession led to an increase in the number of tests performed of more than 50% over the period and reduced the time to access the test.

Evaluation of socio-economic insecurity in peripheral artery disease patients.

The social and economic environment has become a major determinant of cardiovascular health. The objective of our study was to assess socio-economic insecurity in patients with symptomatic PAD. The PRECAR study was a non-interventional prospective cohort study. Patients were recruited from the Vascular Medicine and Surgery Departments of Grenoble-Alpes University Hospital or during a consultation as part of the therapeutic education program "On the move! Better understanding and better living with arterial disease". The analysis of socio-economic and environmental data was based on the EPICES score (a reliable index used to measure individual deprivation) and INSEE parameters (level of education and socio-professional category). Cardiovascular risk factors were also recorded. 150 patients with symptomatic PAD were included between November 2017 and June 2018. 84% were men. In our population 54% (CI95% 45.7 - 62.1) were in a precarious situation compared to 40% (CI95% 39.8 - 40.2) in the general population, according to the EPICES score (P<0.001). Levels of education were low and patients with a baccalaureate or higher education degree were under-represented. Executives, intellectuals and intermediate professions were also under-represented in the PAD population. This data opens new perspectives on the social characterisation of patients that may contribute to improving the outcomes of patients with peripheral vascular disease.

Direct oral anticoagulant (DOAC) versus low-molecular-weight heparin (LMWH) for the treatment of cancer-associated thrombosis (which agent for which patient).

Venous thromboembolism (VTE) is a common complication among patients with cancer, associated with significant higher rate of mortality and morbidity. Low-molecular-weight heparin (LMWH) as a single therapeutic is considered as the standard of care for the treatment of acute cancer-associated thrombosis for many years, showing a significant 40% reduction of recurrent VTE (RR: 0.58; 95% CI, 0.43 - 0.77) without a significant increase of major bleeding complications compared to VKA (RR: 1.09; 95% CI 0.55 - 2.12). Based on results analysis studies only including patients with proximal DVT or PE the risk of recurrent VTE was similar in the DOAC and the LMWH (RR 0.68; 95% CI, 0.39 - 1.17) groups, without significantively increasing the risk of either major bleeding (RR = 1.32; 95% CI 0.7 - 2.47) or CRNMB (RR 1.6; 95% 0.99 - 2.6). Compared with LMWH, the risk of major bleeding and clinically relevant-non major bleeding was higher, although non-significantly, with DOACs than with LMWH, underlying that DOACs should be avoided in patients at high risk of bleeding. The higher risk of bleeding reported in DOACs-treated patients appears related to an excess of upper GI bleeding. In addition to GI cancer, other high-risk features associated with bleeding complications are an urothelial cancer, drug-drug interactions and use of anticancer drugs associated with GI toxicity. Overall, DOACs are an effective treatment option, and safe in most cancer patients with acute VTE. Nonetheless, DOACs should be used with caution in cancer patients at high risk for bleeding due to cancer site and stage per se or to cancer treatments.

Appendicular myxoglobulosis; a rare form of appendicular mucocele.

Myxoglobulosis is a particular, rare, form of appendicular mucocele, characterized by the presence of numerous, occasionally calcified, globules that are grouped together like grapes, and look like pearls or fish eggs, in the appendicular lumen. The diagnosis of myxoglobulosis is most often fortuitous, but sometimes, can be made in the face of acute appendicitis or another setting of abdominal pain. Imaging (sonography or computerized tomography (CT)) is highly suggestive when it shows a cystic, encapsulated, oblong, well-delineated mass, containing (heterogeneous, liquid, and viscous) mucus with calcified globules. In contrast to acute appendicitis, the wall of the appendix is thin (<6mm) and there is no peri-appendicular inflammation. Long-term complications are similar to other appendicular mucoceles, including invagination, bleeding, perforation, peritonitis and peritoneal pseudomyxoma.

Redistribution of clathrin-coated vesicle adaptor complexes during adipocytic differentiation of 3T3-L1 cells.

Mechanisms for intracellular retention of proteins are induced during adipocytic differentiation of 3T3-L1 cells. To investigate the potential role of clathrin lattices in these retention processes, we performed a morphological and biochemical analysis of coated vesicle components in 3T3-L1 cells. Optical sectioning and image restoration revealed a marked increase in the staining of clathrin and beta adaptins in the perinuclear region of cells with differentiation. In addition, predominance of beta (subunit of the AP-2, plasma membrane adaptor) over beta' (subunit of the AP-1, Golgi adaptor) adaptin was observed in immunoblots of clathrin-coated vesicles purified from nondifferentiated fibroblasts, and this ratio was reversed in coated vesicles purified from differentiated adipocytes. These results indicate that the relative abundance of TGN-derived clathrin lattices increases markedly during adipocytic differentiation. Subcellular fractionation indicated that cytosolic AP-1 and AP-2 adaptors comprised approximately 70% of the total cellular adaptor pool. Interestingly, neither the concentration nor the relative ratio of cytosolic AP-1 to AP-2 adaptors increased significantly during differentiation. These data suggest that the increase in TGN-derived lattices results from differentiation-induced mechanisms for enhanced assembly or stabilization of adaptors on Golgi membranes. Interestingly, double-immunofluorescence microscopy also revealed that whereas extensive colocalization between clathrin and beta adaptins occurred both in fibroblasts and adipocytes, structures stained only with anti-adaptin antibody could be detected. Taken together these results suggest that membranes coated with adaptors, but not clathrin, can exist in these cells.

Potential sites of PI-3 kinase function in the endocytic pathway revealed by the PI-3 kinase inhibitor, wortmannin.

Previously we have shown that PDGF receptor mutants that do not bind PI-3 kinase internalize after ligand binding, but fail to downregulate and degrade. To define further the role of PI-3 kinase in trafficking processes in mammalian cells, we have investigated the effects of a potent inhibitor of PI-3 kinase activity, wortmannin. At nanomolar concentrations, wortmannin inhibited both the transfer of PDGF receptors from peripheral compartments to juxtanuclear vesicles, and their subsequent degradation. In contrast, the delivery of soluble phase markers to lysosomes, assessed by the accumulation of Lucifer yellow (LY) in perinuclear vesicles after 120 min of incubation, was not blocked by wortmannin. Furthermore, wortmannin did not affect the rate of transferrin uptake, and caused only a small decrease in its rate of recycling. Thus, the effects of wortmannin on PDGFr trafficking are much more pronounced than its effects on other endocytic events. Unexpectedly, wortmannin also caused a striking effect on the morphology of endosomal compartments, marked by tubulation and enlargement of endosomes containing transferrin or LY. This effect was somewhat similar to that produced by brefeldin A, and was also blocked by pre-treatment of cells with aluminum fluoride (AlF4-). These results suggest two sites in the endocytic pathway where PI-3 kinase activity may be required: (a) to sort PDGF receptors from peripheral compartments to the lysosomal degradative pathway; and (b) to regulate the structure of endosomes containing lysosomally directed and recycling molecules. This latter function could be mediated through the activation of AlFt4-)-sensitive GTP-binding proteins downstream of PI-3 kinase.

A double leucine within the GLUT4 glucose transporter COOH-terminal domain functions as an endocytosis signal.

The unique COOH-terminal 30-amino acid region of the adipocyte/skeletal muscle glucose transporter (GLUT4) appears to be a major structural determinant of this protein's perinuclear localization, from where it is redistributed to the cell surface in response to insulin. To test whether an underlying mechanism of this domain's function involves glucose transporter endocytosis rates, transfected cells were generated expressing exofacial hemagglutinin epitope (HA)-tagged erythrocyte/brain glucose transporter (GLUT1) or a chimera containing the COOH-terminal 30 amino acids of GLUT4 substituted onto this GLUT1 construct. Incubation of COS-7 or CHO cells expressing the HA-tagged chimera with anti-HA antibody at 37 degrees resulted in an increased rate of antibody internalization compared to cells expressing similar levels of HA-tagged GLUT1, which displays a cell surface disposition. Colocalization of the internalized anti-HA antibody in vesicular structures with internalized transferrin and with total transporters was established by digital imaging microscopy, suggesting the total cellular pool of transporters are continuously recycling through the coated pit endocytosis pathway. Mutation of the unique double leucines 489 and 490 in the rat GLUT4 COOH-terminal domain to alanines caused the HA-tagged chimera to revert to the slow endocytosis rate and steady-state cell surface display characteristic of GLUT1. These results support the hypothesis that the double leucine motif in the GLUT4 COOH terminus operates as a rapid endocytosis and retention signal in the GLUT4 transporter, causing its localization to intracellular compartments in the absence of insulin.

Exofacial epitope-tagged glucose transporter chimeras reveal COOH-terminal sequences governing cellular localization.

The insulin-regulated adipocyte/skeletal muscle glucose transporter (GLUT4) displays a characteristic steady-state intracellular localization under basal conditions, whereas the erythrocyte/brain transporter isoform (GLUT1) distributes mostly to the cell surface. To identify possible structural elements in these transporter proteins that determine their cellular localization, GLUT1/GLUT4 chimera cDNA constructs that contain the hemagglutinin epitope YPYDVPDYA (HA) in their major exofacial loops were engineered. Binding of monoclonal anti-HA antibody to non-permeabilized COS-7 cells expressing HA-tagged transporter chimeras revealed that expression of transporters on the cell surface was strongly influenced by their cytoplasmic COOH-terminal domain. This method also revealed a less marked, but significant effect on cellular localization of amino acid residues between transporter exofacial and middle loops. The subcellular distribution of expressed chimeras was confirmed by immunofluorescence microscopy of permeabilized COS-7 cells. Thus, HA-tagged native GLUT4 was concentrated in the perinuclear region, whereas a chimera containing the COOH-terminal 29 residues of GLUT1 substituted onto GLUT4 distributed to the plasma membrane, as did native GLUT1. Furthermore, a chimera composed of GLUT1 with a GLUT4 COOH-terminal 30-residue substitution exhibited a predominantly intracellular localization. Similar data was obtained in CHO cells stably expressing these chimeras. Taken together, these results define the unique COOH-terminal cytoplasmic sequences of the GLUT1 and GLUT4 glucose transporters as important determinants of cellular localization in COS-7 and CHO cells.

Contributions of quisqualate and NMDA receptors to the induction and expression of LTP.

The contributions of two subclasses of excitatory amino acid transmitter receptors to the induction and expression of long-term potentiation (LTP) were analyzed in hippocampal slices. The quisqualate/kainate receptor antagonist DNQX (6,7-dinitro-quinoxaline-2,3-dione) blocked 85% of the evoked field potential, leaving a small response that was sensitive to D-AP5 (D-2-amino-5-phosphonopentanoate), an N-methyl-D-aspartate (NMDA) receptor blocker. This residual D-AP5-sensitive response was of comparable size in control and previously potentiated inputs. High-frequency stimulation in the presence of DNQX did not result in the development of robust LTP. Washout of the drug, however, revealed the potentiation effect. Thus NMDA-mediated responses can induce, but are not greatly affected by, LTP; non-NMDA receptors, conversely, mediate responses that are not needed to elicit LTP but that are required for its expression.

Disruption of PDGF receptor trafficking by mutation of its PI-3 kinase binding sites.

Human platelet-derived growth factor receptors (PDGFRs) expressed in human Hep G2 cells internalized and concentrated in a juxtanuclear region near the Golgi network within 10 minutes after the cells were treated with PDGF. A PDGFR mutant (F5) that lacks high-affinity binding sites for the Src homology 2 domain-containing proteins phosphatidylinositol-3 kinase (PI-3 kinase), Ras guanosine triphosphatase activating protein, phospholipase C-gamma, and a phosphotyrosine phosphatase (Syp) remained at the cell periphery. Restoration of the PI-3 kinase binding sites on F5 completely restored the ability of the receptor to concentrate intracellularly. A PDGFR mutant lacking only PI-3 kinase binding sites failed to concentrate intracellularly. Thus, PI-3 kinase binding sites appear both necessary and sufficient for the normal endocytic trafficking of the activated PDGFR.

Aligning research to meet policy objectives for migrant families: an example from Canada.

BACKGROUND: 'Evidence-based policy making' for immigrants is a complicated undertaking. In striving toward this goal, federal Canadian partners created the Metropolis Project in 1995 to optimize a two-way transfer of knowledge (researchers - policy makers) within five Canadian Centres of Excellence focused on migrants newly arrived in Canada. Most recently, Metropolis federal partners, including the Public Health Agency of Canada, defined one of six research priority areas as, immigrant 'families, children, and youth'. In order to build on previous work in the partnership, we sought to determine what has been studied within this research-policy partnership about immigrant 'families, children, and youth' since its inception. METHODS: Annual reports and working papers produced in the five Centres of Excellence between 1996-2006 were culled. Data on academic works were extracted, results coded according to eleven stated federal policy priority themes, and analyzed descriptively. RESULTS: 139 academic works were reviewed. All federal priority themes, but few specific policy questions were addressed. The greatest volume of policy relevant works were identified for Services (n = 42) and Education and Cultural Identity (n = 39) priority themes. CONCLUSION: Research conducted within the last 10 years is available to inform certain, not all, federal policy questions. Greater specificity in federal priorities can be expected to more clearly direct future research within this policy-research partnership.

Long-term weekly treatment of colorectal metastatic cancer with fluorouracil and leucovorin: results of a multicentric prospective trial of fluorouracil dosage optimization by pharmacokinetic monitoring in 152 patients.

PURPOSE: A relationship between fluorouracil (5-FU) dose and response has been previously shown in advanced colorectal cancer. In a previous study with 5-FU stepwise dose escalation in a weekly regimen, and pharmacokinetic monitoring, we defined a therapeutic range for 5-FU plasma levels: 2,000 to 3,000 microg/L (area under the concentration-time curve at 0 to 8 hours [AUC0-8], 16 to 24 mg x h/L). The current study investigated 5-FU therapeutic intensification with individual dose adjustment in a multicentric phase II prospective trial. PATIENTS AND METHODS: Weekly high-dose 5-FU was administered by 8-hour infusion with 400 mg/m2 leucovorin. The initial dose of 5-FU (1,300 mg/m2) was adapted weekly according to 5-FU plasma levels, to reach the therapeutic range previously determined. RESULTS: A total of 152 patients entered the study from December 1991 to December 1994: 117 patients with measurable metastatic disease and 35 with assessable disease. Toxicity was mainly diarrhea (39%, with 5% grade 3) and hand-foot syndrome (30%, with 2% grade 3). Among 117 patients with measurable disease, 18 had a complete response (CR), 48 a partial response (PR), 35 a minor response (MR) and stable disease (SD), and 16 progressive disease (PD). Median overall survival time was 19 months. The 5-FU therapeutic plasma range was rapidly reached with a variable 5-FU dose in the patient population: mean, 1,803 +/- 386 mg/m2/wk (range, 950 to 3,396). Thirteen patients were immediately in the toxic zone, whereas 51 required a > or = 50% dose increase. CONCLUSION: Individual 5-FU dose adjustment with pharmacokinetic monitoring provided a high survival rate and percentage of responses, with good tolerance.

Changes in blood CD8+ lymphocyte activation status and plasma HIV RNA levels during antiretroviral therapy.

OBJECTIVE: To analyse the relationship between CD8+ lymphocyte phenotype alterations and plasma HIV RNA levels in HIV-infected patients treated with the zidovudine-didanosine combination. METHODS: A total of 30 HIV-infected patients who had never received antiretroviral therapy and who were starting treatment with a combination of zidovudine and didanosine were prospectively studied. Multiparameter flow cytometric analysis of CD8+ lymphocytes and plasma HIV RNA determination were performed on day 0, day 15 and monthly from months 1 to 6. RESULTS: Patients were divided into three categories according to the time-course of plasma HIV RNA levels. In 14 patients, an early and sustained fall in plasma HIV RNA to below the detection limit (500 copies/ml) was observed; in 10 patients, the fall was transient; in six patients, plasma HIV RNA was always detectable (non-responders). The mean CD4+ lymphocyte gain was 120 x 10(6)/l at month 6 in sustained and transient responders, and 55 x 10(6)/l in non-responders. A significant fall in the proportion of CD8+ lymphocytes with an activated phenotype was observed only in the two groups of responders, and was higher in the sustained responders (CD38+HLA-DR+, -56.8%; CD38+CD45RO+, -54.0%; HLA-DR+CD45RO+, -48.4%; CD38+CD28-, -47.3%). CONCLUSION: A fall in the proportion of activated CD8+ lymphocytes is associated with the disappearance of HIV RNA from plasma during antiretroviral therapy. Undetectable plasma HIV RNA is not associated with a return to normal CD8+ lymphocyte activation status after 6 months of treatment, suggesting that viral replication persists in lymphoid tissues.

Septo-hippocampal neurons in the aged rat: relation between their electrophysiological and pharmacological properties and behavioral performances.

The performances of aged (24-26 months) rats in two behavioral tasks (passive avoidance and spontaneous alternation) have been studied. Subpopulations of old animals were found to be impaired in these tasks. Most of the impaired animals, however, were not impaired in both tasks. The properties of the septo-hippocampal neurons (SHNs) were subsequently studied in the same group of experimental animals, anesthetized with urethane, using electrophysiological techniques. The spontaneous activity of SHNs displaying a rhythmically bursting activity (RBA) was significantly higher in animals impaired in the spontaneous alternation task. The proportion of SHNs with RBA was significantly lower and the frequency of the RBA was higher in animals impaired in the passive avoidance task. The pharmacological properties of the SHNs were not significantly different in the various groups. The significance of these complex correlations with regard to the age-related alterations of SHNs properties is discussed.

Evidence of mitochondrial impairment during cardiac allograft rejection.

NADH laser fluorimetry and mitochondrial oxigraphy were used to study myocardial oxidative energy metabolism during cardiac allograft rejection. Heterotopic cardiac transplantation was performed on Lewis rats; allografts (with Fischer rat donors) were compared with isografts (with Lewis rat donors). In vivo and in vitro assays were performed six days after transplantation. Myocardial NADH fluorescence was recorded in vivo from grafted hearts, at baseline; during brief, complete ischemia; and during reperfusion. Oxygen consumption of mitochondria isolated from both native and grafted hearts was determined. Neither baseline levels nor maximum ischemic levels of NADH fluorescence (F0 = k[NADH]) were found to be significantly different between allografts (0.45 +/- 0.05 to 0.87 +/- 0.10) and isografts (0.45 +/- 0.04 to 1.11 +/- 0.05). During recovery, the rate of fluorescence decrease was significantly lower in allografts than in isografts (0.024 +/- 0.001 vs. 0.038 +/- 0.002 delta F0.s-1, P less than 10(-3], indicating a lower rate of NADH reoxidation. In the presence of malate and glutamate substrates, mitochondrial O2 consumption was significantly lower in allografts than in isografts (30 +/- 9 vs. 100 +/- 15 nanoatoms O2. min-1.mg prot-1, P less than 10(-2]. These results indicate that mitochondrial oxidative metabolism was impaired during the rejection process. Such energy production disturbances may contribute to the dysfunction of rejecting hearts.

Prospective study of CD8+ lymphocyte activation in relation to viral load in HIV-infected patients with > or = 400 CD4+ lymphocytes per microliter.

To investigate the temporal relationship between CD8+ lymphocyte phenotypic alterations, the CD4+ T cell decline, and plasma HIV RNA levels during the natural history of HIV infection, 33 treatment-naive HIV-infected patients with > or =400 CD4+ cells/microl were studied prospectively for 3 years. During the study period, 20 patients remained untreated, and only 6 received more than 6 months of therapy. A significant relationship was found between changes in plasma HIV RNA and changes in the proportion of CD38+CD8+ cells. Conversely, the number of CD4+ T cells lost per year was strongly related to the increase in the proportion of CD28-CD8+ T cells. A strong relationship between mean yearly changes in CD4+ T cell numbers and changes in HIV RNA was also observed. CD4+ T cell changes were associated with changes in both viral load and CD8+ T cell activation. These results provide support for the use of both virologic and immunologic parameters for prognosis and management during HIV infection.