Calcium imaging of muscle cells treated with snake myotoxins reveals toxin synergism and presence of acceptors.

Snake myotoxins have a great impact on human health worldwide. Most of them adopt a phospholipase A2 fold and occur in two forms which often co-exist in the same venom: the Asp49 toxins hydrolyse phospholipids, whilst Lys49 toxins are enzymatically inactive. To gain insights into their mechanism of action, muscle cells were exposed to Bothrops myotoxins, and cytosolic Ca(2+) and cytotoxicity were measured. In both myoblasts and myotubes, the myotoxins induced a rapid and transient rise in cytosolic [Ca(2+)], derived from intracellular stores, followed, only in myotubes, by a large Ca(2+) influx and extensive cell death. Myoblast viability was unaffected. Notably, in myotubes Asp49 and Lys49 myotoxins acted synergistically to increase the plasma membrane Ca(2+) permeability, inducing cell death. Therefore, these myotoxins may bind to acceptor(s) coupled to intracellular Ca(2+) mobilization in both myoblasts and myotubes. However, in myotubes only, the toxins alter plasma membrane permeability, leading to death.

Dynamic properties of an inositol 1,4,5-trisphosphate- and thapsigargin-insensitive calcium pool in mammalian cell lines.

The functional characteristics of a nonacidic, inositol 1,4,5-trisphosphate- and thapsigargin-insensitive Ca2+ pool have been characterized in mammalian cells derived from the rat pituitary gland (GH3, GC, and GH3B6), the adrenal tissue (PC12), and mast cells (RBL-1). This Ca2+ pool is released into the cytoplasm by the Ca2+ ionophores ionomycin or A23187 after the discharge of the inositol 1,4,5-trisphosphate-sensitive store with an agonist coupled to phospholipase C activation and/or thapsigargin. The amount of Ca2+ trapped within this pool increased significantly after a prolonged elevation of intracellular Ca2+ concentration elicited by activation of Ca2+ influx. This pool was affected neither by caffeine-ryanodine nor by mitochondrial uncouplers. Probing mitochondrial Ca2+ with recombinant aequorin confirmed that this pool did not coincide with mitochondria, whereas its homogeneous distribution across the cytosol, as revealed by confocal microscopy, and its insensitivity to brefeldin A make localization within the Golgi complex unlikely. A proton gradient as the driving mechanism for Ca2+ uptake was excluded since ionomycin is inefficient in releasing Ca2+ from acidic pools and Ca2+ accumulation/release in/from this store was unaffected by monensin or NH4Cl, drugs known to collapse organelle acidic pH gradients. Ca2+ sequestration inside this pool, thus, may occur through a low-affinity, high-capacity Ca2+-ATPase system, which is, however, distinct from classical endosarcoplasmic reticulum Ca2+-ATPases. The cytological nature and functional role of this Ca2+ storage compartment are discussed.

Mitochondrial Ca2+ as a key regulator of cell life and death.

Mitochondrial Ca(2+) homeostasis is today at the center of wide interest in the scientific community because of its role both in the modulation of numerous physiological responses and because of its involvement in cell death. In this review, we briefly summarize a few basic features of mitochondrial Ca(2+) handling in vitro and within living cells, and its involvement in the modulation of Ca(2+)-dependent signaling. We then discuss the role of mitochondrial Ca(2+) in the control of apoptotic death, focusing in particular on the effects of pro- and anti-apoptotic proteins of the Bcl-2 family. Finally, the potential involvement of Ca(2+) and mitochondria in the development of two diseases, Ullrich muscular dystrophy and familial Alzheimer's disease, is briefly discussed.

Chimeric green fluorescent protein as a tool for visualizing subcellular organelles in living cells.

BACKGROUND: It has recently been demonstrated that the green fluorescent protein (GFP) of the jellyfish Aequorea victoria retains its fluorescent properties when recombinantly expressed in both prokaryotic (Escherichia coli) and eukaryotic (Caenorhabditis elegans and Drosophila melanogaster) living cells; it can therefore be used as a powerful marker of gene expression in vivo. The specific targeting of recombinant GFP within cells would allow it to be used for even more applications, but no information is yet available on the possibility of targeting GFP to intracellular organelles. RESULTS: In this study, we show that the GFP cDNA can be expressed at high levels in cultured mammalian cells; the recombinant polypeptide is highly fluorescent and is exclusively localized in the cytosol. Furthermore, we have modified the GFP cDNA to include a mitochondrial targeting sequence (and a strong immunological epitope at the amino terminus of the encoded polypeptide). When transiently transfected into mammalian cells, this construct drives the expression of a strongly fluorescent GFP chimera which selectively localizes to the mitochondria. We also describe two of the many possible applications of this recombinant GFP in physiological studies. The targeted chimera allows the visualization of mitochondrial movement in living cells. Also, unlike dyes such as rhodamine, it reveals morphological changes induced in mitochondria by drugs that collapse the organelle membrane potential. Moreover, when GFP is cotransfected with a membrane receptor, such as the alpha 1-adrenergic receptor, the fluorescence of the GFP in intact cells can be used in recognizing the transfected cells. Thus, specific changes in intracellular Ca2+ concentration that occur in cells expressing the recombinant receptor can be identified using a classical fluorescent Ca2+ indicator. CONCLUSION: GFP is an invaluable new tool for studies of molecular biology and cell physiology. As a marker of transfection in vivo, it provides a simple means of identifying genetically modified cells to be used in physiological studies. More importantly, chimeric GFP, which in principle can be targeted to any subcellular location, can be used to monitor complex phenomena in intact living cells, such as changes in shape and distribution of organelles, and it has the potential to be used as a probe of physiological parameters.

Delayed activation of the store-operated calcium current induced by calreticulin overexpression in RBL-1 cells.

Calreticulin (CRT) is a high-capacity, low-affinity Ca2+-binding protein located in the lumen of the endoplasmic reticulum (ER) of all eukaryotic cells investigated so far. Its high level of conservation among different species suggests that it serves functions fundamental to cell survival. The role originally proposed for CRT, i.e., the main Ca2+ buffer of the ER, has been obscured or even casted by its implication in processes as diverse as gene expression, protein folding, and cell adhesion. In this work we seek the role of CRT in Ca2+ storing and signaling by evaluating its effects on the kinetics and amplitude of the store-operated Ca2+ current (ICRAC). We show that, in the rat basophilic leukemia cell line RBL-1, overexpression of CRT, but not of its mutant lacking the high-capacity Ca2+-binding domain, markedly retards the ICRAC development, however, only when store depletion is slower than the rate of current activation. On the contrary, when store depletion is rapid and complete, overexpression of CRT has no effect. The present results are compatible with a major Ca2+-buffering role of CRT within the ER but exclude a direct, or indirect, role of this protein on the mechanism of ICRAC activation.

Characterization of lymphoma-derived cell lines: comparison of cell lines positive and negative for Epstein-Barr virus nuclear antigen. I. Physical, cytogenetic, and growth characteristics.

Sixteen lymphoid cell lines were derived from patients with undifferentiated lymphoma of Burkitt's or non-Burkitt's type. They were obtained directly from tumor biopsies, from serous effusions, or from bone marrow. In 10 of the cell lines, the Epstein-Barr virus (EBV) nuclear antigen (EBNA) was undetectable; the remaining 6 lines were EBNA-positive (EB-pos). Of the 16 lines, 15 were aneuploid, with detectable chromosome "14q+ markers (11 had +8;14 translocations). These 15 lines, which included the EBNA-negative (EB-neg) lines, were believed to be of tumor cell origin. The remaining line consisted predominantly of diploid cells derived from normal lymphocytes, but some cells of tumor origin were present. Four EB-pos cell lines derived from EB-neg tumors had an aneuploid karyotype consistent with an origin from tumor cells (including no.8;14 translocation in two), which suggested that either tumor cells were infected with EBV in vitro or a tiny fraction of EB-pos tumor cells (or potential tumor cells) present in vivo gave rise to the predominant cell of the line. EB-neg B-cell lines and EB-pos cell lines established from undifferentiated lymphomas differed greatly. EB-neg lines had consistently smaller electronic mean cell volumes and narrow-angle light scatter than did EB-pos lines. This finding correlated with a lower nuclear:cytoplasmic ratio in EB-pos lines. EB-neg lines also had higher saturation cell densities than did EB-pos lines under standard culture conditions. The data indicate either that EBV influences the morphologic and physiologic characteristics of lymphoid cell lines or that EB-neg B-cell lines and EB-pos cell lines are derived ultimately from different lymphocyte subpopulations or that both may apply.

Characterization of lymphoma-derived cell lines: comparison of cell lines positive and negative for Epstein-Barr virus nuclear antigen. II. Surface markers.

Fifteen of 16 lymphoma-derived cell lines and the Faji and P3HR1 cell lines were characterized with regard to certain surface markers, particularly immunoglobulins, complement receptors, Epstein-Barr virus (EBV) receptors, and Fc receptors. Ten lines positive for EBV nuclear antigen (EB-pos) were stained weakly or not at all by antihuman immunoglobulin fluorescein isothiocyanate conjugates, whereas EBV nuclear antigen negative (EB-neg) cell lines stained brightly. EB-pos lines frequently manifested Fc receptors, particularly for 7S antibody, whereas EB-neg lines did not. Receptors for the C3b component of complement and for EBV, which correlated significantly with each other, were expressed to a much lesser extent by EB-neg lines than by EB-pos lines. These findings are pertinent to an understanding of the infrequent association of this virus with American undifferentiated lymphomas of the Burkitt's and non-Burkitt's types.

Characterization of the Epstein-Barr virus isolated from a cell line derived from a patient with American Burkitt's lymphoma.

Epstein-Barr viral (EBV) DNA is nearly always detectable in African Burkitt's lymphoma (BL) but is infrequently found in the histologically indistinguishable American BL. We have derived a tumor cell line from a patient with American BL which produces EBV, and we have compared this virus isolate [JLP(c)] with African BL EBV. The American JLP(c) virus immortalizes human umbilical cord lymphocytes in vitro, and its DNA is indistinguishable from African BL EBV DNA by nucleic acid hybridization and preliminary restriction endonuclease cleavage analysis.

Examination of Epstein-Barr virus and C-type proviral sequences in American and African lymphomas and derivative cell lines.

While Epstein-Barr viral (EBV) DNA is nearly always detectable in African Burkitt's lymphoma (BL), the relatively low frequency of BL in EBV-positive African children and the infrequent finding of EBV in American BL suggest that other cofactors may contribute to the malignant transformation. Among these possible cofactors are type C oncornaviruses. To evaluate this possibility, we screened the cellular DNA from 16 lymphomas (2 African, 14 American) and the DNA from 20 lymphoma-derived cell lines (4 African, 16 American) with a radiolabeled viral DNA probe from EBV and two oncornaviral probes (murine amphotropic 1504A virus and simian sarcoma virus). The radiolabeled EBV DNA probe hybridized with 18 of 36 tumor or cell line DNA's. Only 2 of 11 American BL tumors contained detectable EBV sequences. However, the cell lines derived from three EBV-negative tumors converted in vitro to EBV positivity, suggesting that some of the tumor cells could be infected with EBV. In contrast, none of the tumors or the cell lines derived therefrom hybridized with either the 1504A or the simian sarcoma virus probes, decreasing the likelihood that type C viruses are cofactors with EBV.

Controlled clinical trials of nutritional intervention as an adjunct to chemotherapy, with a comment on nutrition and drug resistance.

Nutritional intervention in the cancer patient [e.g., total parenteral nutrition (TPN)] might improve durable survival because of increased tolerance to aggressive tumor therapy. To determine whether this assumption is correct, 42 patients with diffuse histiocytic lymphoma were induced with prednisone, high-dose methotrexate, Adriamycin, cyclophosphamide, and VP-16 (ProMACE). Nitrogen mustard-vincristine-procarbazine-prednisone (MOPP) consolidation was then used, followed by late intensification with ProMACE. Patients were selected randomly to receive adjuvant TPN or a standard diet during ProMACE-MOPP treatment. While TPN patients had a greater median weight gain than did control patients, lean body mass and degree of myelosuppression did not improved as a consequence of TPN. There was no significant difference in tumor response or survival between TPN and control patients, whether or not the patients were initially malnourished. In a second trial, 32 young patients with metastatic or other poor-prognosis sarcomas were randomly allocated to receive TP or a standard diet as an adjunct to one very intensive course of combination chemotherapy or chemotherapy plus total body irradiation; autologous marrow transplantation was used with gain than did controls but remained in a negative nitrogen balance. Response rates and median durable survival did not differ between the two groups. In both trials, the maximum nutritional support permitted by currently available technology was offered. Thus, the limiting factor may not be nutritional status but rather the intrinsic biology of the tumors and the limitations of their response to current therapy. In in vitro studies of the possible influence of nutrition on cancer treatment, we have compared sublines of P388 murine leukemia cells which are sensitive or resistant to Adriamycin. The difference in drug sensitivity correlated with differences in lipid composition, with more intracellular lipid, and with greater membrane rigidity in the resistant cells. Resistant cells have a relatively poor transport of drug into the cell; moreover, intracellular Adriamycin is sequestered in lipid depots away from DNA. These results suggest one possible relationship between nutritional phenomena and drug sensitivity.

Randomized trial of recombinant human granulocyte-macrophage colony-stimulating factor in pediatric patients receiving intensive myelosuppressive chemotherapy.

PURPOSE: To evaluate whether recombinant human granulocyte-macrophage colony-stimulating factor (GM-CSF) reduces the hematologic toxicities and supportive care requirements of an intensive combination chemoradiotherapy regimen in pediatric and young adult sarcoma patients. PATIENTS AND METHODS: Thirty-seven newly diagnosed patients age 1 to 25 years were randomized to receive 18 cycles of chemotherapy alone or with GM-CSF beginning in cycle 3. GM-CSF (5 to 15 micrograms/kg/d subcutaneously) was begun 24 hours after the completion of chemotherapy and continued through day 19 of each cycle or until the absolute granulocyte count (AGC) was > or = 500/microliter on 2 consecutive days. RESULTS: GM-CSF reduced the median duration of grade 4 granulocytopenia from 9.0 days (range, 2 to 24) to 7.0 days (range, 1 to 21) (P < .0001), but did not significantly affect the grade of granulocyte nadir. No differences were seen in the incidence or types of infectious complications, incidence or duration of hospitalization and antimicrobial therapy, response to chemotherapy, or event-free or overall survival. GM-CSF was associated with more severe and protracted thrombocytopenia (median platelet nadir, 29,500/microliter [range, 3,000 to 288,000] v 59,000/microliter [range, 3,000 to 309,000], P < .0001; median time to recovery > 75,000/microliter, 16.0 days [range, 0 to 61] v 14.0 days [range, 0 to 38], P < .0001). CONCLUSION: GM-CSF does not produce clinically meaningful reductions in the degree or duration of severe granulocytopenia following intensive multiagent chemotherapy, but is associated with worsened thrombocytopenia. GM-CSF also does not reduce the need for hospitalization or the incidence of febrile neutropenia and infectious complications. We conclude that the costs and increased toxicities associated with the use of this agent are not justified by its minimal clinical benefit for regimens of this level of intensity.

A prospective randomized trial comparing the infectious and noninfectious complications of an externalized catheter versus a subcutaneously implanted device in cancer patients.

PURPOSE: To compare the frequency of infectious episodes or other problems occurring with an externalized catheter (Hickman) versus a subcutaneously implanted device (Port-a-Cath, Pharmacia, Piscataway, NJ) in cancer patients, we performed a prospective, randomized study in 100 cancer patients (age range, 5 to 74 years). PATIENTS AND METHODS: Patients who were chemotherapy candidates and required an indwelling catheter were monitored prospectively and evaluated during the 180 days after the insertion of the catheter and again at time of study closure. The frequency of catheter use, reason for access, and any problems that might have been related to catheter use were noted. All data were collected prospectively and included the patient's age, sex, underlying malignancy, temperature, and leukocyte and absolute granulocyte counts at the time of catheter insertion and when complications occurred. The time to and reason for removal of the catheter, as well as any intercurrent infectious or mechanical problems, were also determined. RESULTS: Most of the infections that occurred were caused by gram-positive organisms, especially staphylococci or streptococci. A total of 22 complications (11 in each group) resulted in removal of the central line. Only one infection in the Hickman catheter group and four in the Port-a-Cath group led to removal of the central line. All other infectious episodes were successfully treated without removal of the catheters. The mean device life was 230 days for the Hickman catheter and 318 days for the Port-a-Cath (not significant). CONCLUSION: There were no differences between the two study groups regarding incidence of documented infections or mechanical or thrombotic complications.

A prospective randomized trial evaluating prophylactic antibiotics to prevent triple-lumen catheter-related sepsis in patients treated with immunotherapy.

During a 15-month period, 92 patients undergoing 129 treatment episodes of immunotherapy with interleukin-2 (IL-2) alone or with immune cells underwent insertion of central venous catheters (CVCs) in the Surgery Branch, National Cancer Institute. Before each catheter insertion patients were prospectively randomized into one of three treatment groups; therapy with intravenous (IV) placebo using D5W, IV oxacillin, or change of the catheter to a new site every 72 hours. The mean duration of catheterization was 3.8 +/- 1.1 days. No patient in the oxacillin arm developed catheter-related sepsis, while eight patients in the control arms (five, line change, three, placebo) developed catheter-related sepsis (P2 = .050). Seven episodes of catheter-related sepsis were due to Staphylococcus aureus and one was due to Staphylococcus epidermidis. Catheter colonization was reduced significantly in the oxacillin arm versus control arms (P = .0001). Staphylococcus aureus, Staphylococcus epidermidis, and other coagulase-negative Staphylococci were sensitive to oxacillin in 89%, 60%, and 50% of cultures, respectively. No evidence of bacterial overgrowth, candida colonization, or candidemia was observed in these patients. Thus this trial demonstrates that treatment with prophylactic oxacillin can decrease the incidence of catheter-related sepsis in patients undergoing immunotherapy with interleukin-2 (IL-2). To our knowledge this is the first prospective randomized trial to evaluate the prophylactic use of systemic antibiotics in the prophylaxis of CVC sepsis.

Detection of mutations in insulin receptor gene by denaturing gradient gel electrophoresis.

Denaturing gradient gel electrophoresis (DGGE) has been used to screen for mutations in the insulin receptor gene. Each of the 22 exons was amplified by the polymerase chain reaction (PCR). For each exon, one of the two PCR primers contained a guanine-cytosine (GC) clamp at its 5' end. The DNA was analyzed by electrophoresis through a polyacrylamide gel containing a gradient of denaturants. Two geometries for the gels were compared; the gradient of denaturants was oriented either parallel or perpendicular to the electric field. The sensitivity of the technique was evaluated by determining whether DGGE succeeded in detecting known mutations and polymorphisms in the insulin receptor gene. With parallel gels, 12 of 16 sequence variants were detected. The use of perpendicular gels increased the sensitivity of detection so that all 16 sequence variants were successfully detected when DNA was analyzed by a combination of perpendicular and parallel gels. Furthermore, DGGE was used to investigate a patient with leprechaunism whose insulin receptor genes had not previously been studied. Two mutant alleles were identified in this patient. The allele inherited from the father had a mutation substituting alanine for Val-28; in the allele inherited from the mother, arginine was substituted for Gly-366.

Interaction of large granular lymphocytes with susceptible target does not induce second messenger and cytolytic granule exocytosis.

We studied the activation signals of LGL, from LDGL patients, following incubation with susceptible K562 target cells. The findings showed that LGL lysis is independent of [Ca2+]i rise and cytolytic granule exocytosis, and most likely involves alternative, as yet unidentified, mechanisms.

Effects of granulocyte colony-stimulating factor and interferon-gamma on antifungal activity of human polymorphonuclear neutrophils against pseudohyphae of different medically important Candida species.

Polymorphonuclear neutrophils (PMNs) are the major host defense against pseudohyphae, the invasive form of Candida species. We studied the effects of granulocyte colony-stimulating factor (G-CSF) and interferon-gamma (IFN-gamma) on the PMN-induced damage of pseudo-hyphae of Candida albicans, Candida tropicalis, and Candida parapsilosis in vitro by using two antifungal assays: a modified limiting dilution assay and a colorimetric metabolic 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. PMNs from healthy volunteers were incubated with either G-CSF (100-10,000 U/ml) or IFN-gamma (10-5000 U/ml) or buffer at 37 degrees C for 90 min and their capacity to damage nonopsonized pseudohyphae was then measured. C. tropicalis appeared to be the most susceptible species, whereas C. parapsilosis showed the highest rate of resistance to PMN damage. G-CSF (500-10,000 U/ml) and IFN-gamma (100-1000 U/ml) enhanced the antifungal activity of PMNs against C. albicans pseudo-hyphae (P < .01 and P < .05). Among the others, G-CSF enhanced PMN-induced damage of C. parapsilosis at concentrations 500-10,000 U/ml (P < .05), whereas it enhanced damage of C. tropicalis only at 10,000 U/ml (P < .01). IFN-gamma (100-1000 U/ml)-primed PMNs also caused augmented damage of C. parapsilosis (P < .05) but not of C. tropicalis at the same concentrations. Species-dependent differences exist in the responses of PMNs to Candida pseudohyphae and G-CSF as well as IFN-gamma are important immunomodulators of phagocytic host defenses against them.

Successful surgical management of neutropenic enterocolitis in two patients with severe aplastic anemia. Case reports and review of the literature.

We describe two patients with severe aplastic anemia in whom neutropenic enterocolitis developed while they were undergoing treatment at the National Institutes of Health. Both patients had progressive symptoms while receiving optimal medical management and both underwent and survived surgical intervention despite continued prolonged neutropenia in the perioperative period. This experience contrasts with six cases reported in the literature and suggests that surgery can be employed even in patients with profound neutropenia. Thus, in patients who remain persistently septic or who develop clinical deterioration despite medical management or who have other indications for surgical intervention, neutropenia should not be a contraindication to the appropriate or necessary procedure.

Protease inhibitor and triple-drug therapy: cellular immune parameters are not restored in pediatric AIDS patients after 6 months of treatment.

OBJECTIVE: To assess whether treatment of HIV-positive children by antiretroviral drugs for a 6-month period would improve immune function significantly. DESIGN AND METHODS: Immunological assessment of 89 HIV-positive children who received protease inhibitor monotherapy for 12-16 weeks as part of phase I/II studies, followed by triple antiretroviral therapy for an additional 12 weeks, was conducted. Immunological parameters were assessed in vitro at four time points (at enrollment, at weeks 2-4, at weeks 12-16, and at weeks 24-28). Assessments included: cytokine production by monocytes, T-cell proliferation to mitogen or recall antigens (including an HIV antigen) and apoptotic cell death. Plasma levels of tumor necrosis factor (TNF)-alpha and soluble TNF receptor (sTNF-R) were also measured, in addition to CD4+ T-lymphocyte counts and viral load. In addition, limited analyses were performed on samples from 17 children after 120 weeks of therapy, including 104 weeks of triple therapy. RESULTS: At enrollment, the 89 children exhibited severe immune defects. Antiretroviral therapy raised CD4+ T-lymphocyte counts significantly and decreased viral loads. In contrast, the in vitro immune parameters studied were not improved, except for plasma levels of sTNF-RII which decreased in parallel with the decrease in viral load. In addition, there was a trend towards increased skin test reactivity for the ritonavir-treated children. No differences were seen in the immune parameters whether the patients were treated with mono- or triple therapy. Results obtained after 120 weeks of therapy demonstrated that defective interleukin-12 production was not restored by long-term therapy. CONCLUSIONS: After 6 months of therapy, with the exception of decreased sTNF-RII levels, and a trend towards increased skin test reactivity, restoration of several defective cellular immune responses did not occur despite significantly decreased viral loads and increased CD4+ T-lymphocyte counts.

Individual prognoses of long-term responses to antiretroviral treatment based on virological, immunological and pharmacological parameters measured during the first week under therapy.

OBJECTIVE: To predict long-term (12 weeks or longer) virological responses to antiretroviral treatment from measurements made during the first few days on therapy. METHODS: Forty-one HIV-1-infected children were treated with ritonavir for 12 weeks followed by triple drug combination treatment, and the kinetics of virus decay in plasma, ritonavir concentration and CD4 cell counts were measured. A robust multivariate pattern recognition method was used for prediction of the longterm virological responses. RESULTS: The virus decay rate constants calculated from measurements of plasma viral RNA concentrations on the first, second, third, fourth and seventh day on therapy, the drug concentrations in the plasma on day seven, and the pretreatment levels of viral RNA and CD4 cell counts, correlated with long-term levels of plasma HIV-1 RNA. The combination of these parameters contained sufficient information for correct and robust prediction of the long-term response in 88% of the treated children. The predictions of individual responses were stable as demonstrated by a cross-validation analysis, which was highly statistically significant (r=0.87) and specific. CONCLUSION: These results demonstrate that multiple parameters determine the response to antiretroviral therapy and offer a very early measure of individual long-term responses, suggesting that treatment could be optimized after few days of therapy.

Relation between stage of disease and neurobehavioral measures in children with symptomatic HIV disease.

OBJECTIVE: To study the relationships between stage of HIV disease, reflected by CD4+ lymphocyte percentages and p24 antigen levels, and HIV-associated central nervous system (CNS) abnormalities, measured by computed tomography (CT) brain-scan ratings and neurobehavioral tests. DESIGN: Consecutive case series. SETTING: Government medical research center. PATIENTS: Eighty-six previously untreated children with symptomatic HIV-1 disease. RESULTS: CD4% measures correlated significantly with overall CT brain-scan severity ratings (r = -0.45; P < 0.001) as well as with its component parts (cortical atrophy, white matter abnormalities, and intracerebral calcifications); they were of comparable magnitude for vertically and transfusion-infected children. CD4% measures were also associated with the general level of cognitive function (r = 0.32; P < 0.005). Furthermore, patients with detectable serum p24 antigen levels (n = 39) had CT brain scans that were more abnormal than patients with undetectable p24 levels (n = 20; CT abnormality ratings of 21.3 versus 35.9; P < 0.02); similar differences were found for the cortical atrophy and calcification ratings. p24 levels also correlated with the overall CT brain-scan severity rating (r = 0.34; P < 0.01). CONCLUSIONS: Degree of CT brain-scan abnormality and level of cognitive dysfunction were significantly associated with the stage of HIV-1 disease, as reflected by either CD4 leukocyte measures or elevations of p24 antigen. The relation between the CT brain-scan lesions and markers of HIV disease (both CD4 and p24) suggest that these CNS abnormalities are most likely associated with HIV-1 infection, and further support the hypothesis that the interaction between systemic disease progression and CNS manifestations is continuous rather than discrete.