Biomedical subjects

A Vaisberg

Publications and source records attributed to A Vaisberg.

At least 19 recordsLinked to original sources

PubMed2001

Immune response to measles vaccine in Peruvian children.

OBJECTIVE: To evaluate the immune response in Peruvian children following measles vaccination. METHODS: Fifty-five Peruvian children received Schwarz measles vaccine (about 10(3) plaque forming units) at about 9 months of age. Blood samples were taken before vaccination, then twice after vaccination: one sample at between 1 and 4 weeks after vaccination and the final sample 3 months post vaccination for evaluation of immune cell phenotype and lymphoproliferative responses to measles and non-measles antigens. Measles-specific antibodies were measured by plaque reduction neutralization. FINDINGS: The humoral response developed rapidly after vaccination; only 4 of the 55 children (7%) had plaque reduction neutralization titres <200 mlU/ml 3 months after vaccination. However, only 8 out of 35 children tested (23%) had lymphoproliferative responses to measles antigens 3-4 weeks after vaccination. Children with poor lymphoproliferative responses to measles antigens had readily detectable lymphoproliferative responses to other antigens. Flow cytometric analysis of peripheral blood mononuclear cells revealed diffuse immune system activation at the time of vaccination in most children. The capacity to mount a lymphoproliferative response to measles antigens was associated with expression of CD45RO on CD4+ T-cells. CONCLUSION: The 55 Peruvian children had excellent antibody responses after measles vaccination, but only 23% (8 out of 35) generated detectable lymphoproliferative responses to measles antigens (compared with 55-67% in children in the industrialized world). This difference may contribute to the less than uniform success of measles vaccination programmes in the developing world.

Antibodies, Viral↗

PubMed1996

Sublingual buprenorphine compared to morphine delivered by a patient-controlled analgesia system as postoperative analgesia after prostatectomy.

After open prostatectomy, 52 patients were randomly allocated to two treatment groups. Group A (26 patients) received buprenorphine sublingually, and in group B (26 patients) the analgesia was induced using a patient-controlled analgesia system with morphine. The total dose of morphine given during the first 24 h was 72 +/- 8 mg compared to 1.6 +/- 0.45 mg of buprenorphine. The total dose of buprenorphine on days 2 and 3 was significantly lower than the total dose of morphine (p < 0.01). There were no significant differences in visual pain scores, side effects, mean arterial blood pressure, pulse rate and respiration rate between the two groups. Sublingual application of buprenorphine offers an effective and easy alternative to the parenteral route of morphine for the management of postoperative pain.

Administration, Sublingual↗

PubMed1995

Brain endothelial cell infection in children with acute fatal measles.

Neurologic diseases are important complications of measles. The role of virus infection of the central nervous system as well as the route of virus entry has been unclear. Five autopsied cases of individuals who died with severe acute measles 3-10 d after the onset of the rash were studied for evidence of viral involvement of the central nervous system. In all cases, in situ hybridization and RT-PCR in situ hybridization techniques showed endothelial cell infection. Immunoperoxidase staining with an anti-ferritin antibody revealed a reactive microgliosis. These data suggest that endothelial cells in the brain are frequently infected during acute fatal measles. This site of infection may provide a portal of entry for virus in individuals who subsequently develop subacute sclerosing panencephalitis or measles inclusion body encephalitis and a target for immunologic reactions in post-measles encephalomyelitis.

Base Sequence↗

PubMed1993

Immunologic parameters 2 years after high-titer measles immunization in Peruvian children.

Immunization with high-titer measles vaccines has been associated with excess mortality in children 2-4 years after vaccination. In this study, immunologic parameters in 64 Peruvian children who had been immunized an average of 27 months earlier with high-titer vaccines were compared with parameters in 76 recipients of low-titer vaccines. Delayed-type hypersensitivity, lymphocyte phenotype distributions by flow cytometry, and lymphoproliferation after phytohemagglutinin (PHA) stimulation were assessed. High-titer recipients had smaller indurations to tetanus, diphtheria, and Proteus (P < .05) antigens, decreased PHA stimulation (P = .04), and a lower percentage of CD4+ lymphocytes (P = .04) than low-titer recipients. After adjustment for sex, concurrent illnesses, and other variables in regression analyses, high-titer recipients had a lower percentage of CD4+ lymphocytes (P = .025) and decreased lymphocyte proliferation to PHA (P = .058). These results may provide a clue to the pathogenesis of delayed excess mortality after high-titer measles vaccination in some developing countries.

Cell Division↗

PubMed1992

Immune activation during measles: beta 2-microglobulin in plasma and cerebrospinal fluid in complicated and uncomplicated disease.

Beta 2-microglobulin (beta 2m) is a small protein that forms the light chain of the class I major histocompatibility molecule and is also present in soluble form in serum and cerebrospinal fluid (CSF). Measles is associated with immune activation and evidence of immunologic abnormalities that persist for several weeks. To assess further the immunologic changes occurring during measles, beta 2m was measured in plasma and CSF. beta 2m became elevated during measles before the onset of the rash and was highest during the rash. Elevations persisted for several weeks and correlated well with levels of soluble interleukin-2 receptor and neopterin and less well with soluble CD8. CSF beta 2m was elevated in postmeasles encephalomyelitis. Plasma levels of beta 2m did not correlate with spontaneous proliferation of peripheral blood mononuclear cells (PBMC) or with in vitro production of beta 2m by cultured PBMC. The data suggest that increases in beta 2m in measles correlate better with cytokine production than with cell proliferation.

Biomarkers↗

PubMed1992

[Cytotoxicity induced by Peruvian snake venom on fibroblasts of mice].

The cytotoxic effect of venoms from six crotalinae Peruvian snakes (Bothrops atrox; B. brazili; B. pictus; B. barnetti; Lachesis m. muta y Crotalus durissus terrificus) was studied in an in vitro system of BALB/c 3T3 fibroblasts grown in Dulbecco modified minimal essential medium at 37 degrees C in a humidified atmosphere of 5% CO2-95% air. The viability of the cells was evaluated 24 hours after the treatment with the different venoms, using the method of exclusion of trypan blue. The six venoms produced cytotoxic effects at 24 hours on the 3T3 fibroblasts. The venom from B. atrox was the most potent (DE50 = 162 ng/ml) and that from B. barnetti the least (DE50 = 7182 ng/ml).

3T3 Cells↗

PubMed1991

Cytokine production in vitro and the lymphoproliferative defect of natural measles virus infection.

In natural measles virus infection, evidence of intense immune system activation is present simultaneously with clinically relevant immune suppression. While evidence of activation is most prominent early in the disease, skin test responses and in vitro lymphoproliferation are depressed for weeks after the onset of the rash. It is not known whether the prolonged period of reduced immune responsiveness results from a single defect or a succession of different abnormalities. To gain further insight into measles-induced immune suppression we studied the production of soluble IL-2 receptor (sIL-2R), interferon-gamma (IFN-gamma), IL-1 beta, and tumor necrosis factor (TNF alpha) by peripheral blood mononuclear cells (PBMC) isolated from measles patients at various times after the onset of the rash. Studies included addition of supplemental recombinant IL-1 beta (rIL-1 beta) or recombinant IL-2 (rIL-2) or suppression of prostaglandin synthesis by indomethacin (IM). Proliferation in response to phytohemagglutin (PHA) was abnormal at all stages of disease. During the acute phase (first week after the onset of the rash) spontaneous production of sIL-2R was increased (76 +/- 54 vs. controls 4 +/- 4; P less than 0.03), suggesting in vivo T cell activation while PHA-induced sIL-2R was decreased (228 +/- 43 vs. control 582 +/- 127; P less than 0.002), suggesting that the capacity to produce IL-2 in response to mitogen was limited. Supplementation of PHA-stimulated cultures with rIL-2 improved but did not normalize both proliferation (58,600 +/- 4900 to 70,700 +/- 4400 vs. control 97,700 +/- 15,500; P less than 0.03) and sIL-2R levels (114 +/- 58 to 309 +/- 87 vs. control 582 +/- 127; P less than 0.003). Both spontaneous (25 +/- 18 vs. control 237 +/- 92; P less than 0.002) and PHA-induced (20 +/- 20 vs. control 604 +/- 129; P less than 0.004) TNF alpha levels were subnormal and were not improved with rIL-2, rIL-1 beta, or IM, suggesting a block in monocyte TNF alpha production. Spontaneous and PHA-induced IFN-gamma and IL-1 beta levels were normal. During the convalescent phase (greater than 2 weeks after the onset of the rash), spontaneous levels of sIL-2R were normal and PHA-induced levels were completely normalized with supplemental rIL-2 but proliferation remained below normal.(ABSTRACT TRUNCATED AT 400 WORDS)

CD4-CD8 Ratio↗

PubMed1990

Spontaneous proliferation of peripheral mononuclear cells in natural measles virus infection: identification of dividing cells and correlation with mitogen responsiveness.

Spontaneous proliferation of peripheral mononuclear cells is pronounced following measles virus infection at a time when patients mount effective humoral and cell-mediated immune responses and manifest a range of poorly understood immunologic abnormalities. We found spontaneous activity (measles 8000 +/- 1200 cpm vs control 1900 +/- 350 cpm; P less than 0.05) to wax and wane abruptly during the first week after the rash in parallel with expression of the lymphocyte activation marker OKT10. At peak activity, approximately 10% of circulating mononuclear cells were actively synthesizing DNA. Double labeling of individual mononuclear cells with autoradiography and immunoperoxidase demonstrated that B and T lymphocytes as well as monocytes participate in the spontaneous activity. Proliferative activity was increased 3- to 20-fold over control levels in all PBMC subsets such that close to one-third of circulating B cells and monocytes and 5-10% of CD4- and CD8-positive T cells were preparing to divide. Mitogen responsiveness was generally decreased in measles patients (58,800 +/- 4600 cpm vs control 97,700 +/- 15,500 cpm; P less than 0.002). Neither spontaneous proliferation nor mitogen responsiveness was correlated with age, sex, or the presence of complications. Patients with the lowest mitogen responses, however, had the greatest increases in B cell (P less than 0.03) and CD8-positive T cell (P less than 0.05) proliferation. These data demonstrate that all major immunologic cell types proliferate in response to measles virus infection. Mechanisms by which spontaneous proliferative activity in individual mononuclear subsets could contribute to depressed mitogen responsiveness are discussed.

Antibody Formation↗

PubMed1990

Immune activation during measles: interferon-gamma and neopterin in plasma and cerebrospinal fluid in complicated and uncomplicated disease.

To study T cell and macrophage activity during measles, levels of interferon-gamma (IFN-gamma) and neopterin in plasma and cerebrospinal fluid (CSF) were measured. Plasma levels of IFN-gamma were elevated in measles (1.17 +/- 0.27) compared with healthy adults (0.13 +/- 0.06, P less than .05) and children (0.14 +/- 0.06, P less than .01). Plasma levels of neopterin were elevated in measles (32.5 +/- 2.7) compared with healthy adults (5.3 +/- 2.9, P less than .0001), healthy children (12.1 +/- 4.0, P less than .001), and children with other infectious diseases (20.6 +/- 4.0, P less than .02). IFN-gamma was increased in measles primarily during rash; neopterin remained elevated for several weeks. Levels of neopterin showed a significant positive correlation with plasma levels of soluble interleukin-2 receptor and soluble CD8, two other parameters of T cell activation. Children with measles complicated by pneumonia had higher levels of neopterin in serum than those with uncomplicated disease. Children with measles complicated by autoimmune encephalomyelitis had higher levels of neopterin in CSF than those with noninflammatory neurologic disease but lower than those with central nervous system infections. Thus, IFN-gamma seems to be produced in vivo during acute measles virus infection; deficiency of this lymphokine does not appear to correlate with increased susceptibility to secondary infections.

Adolescent↗

PubMed1990

Natural killer cell activity during measles.

Natural killer cells are postulated to play an important role in host anti-viral defences. We measured natural killer cell activity in 30 individuals with acute measles (73 +/- 21 lytic units (LU)/10(7) cells) and 16 individuals with other infectious diseases (149 +/- 95 LU) and found it reduced compared with values for adults (375 +/- 70 LU; P less than 0.001) or children (300 +/- 73 LU, P less than 0.01) without infection. Reduced natural killer cell activity was found in measles patients with (84 +/- 30 LU) and without (55 +/- 18 LU) complications and was present for at least 3 weeks after the onset of the rash. Activity was increased by in vitro exposure of cells to interleukin-2. Depressed natural killer cell activity parallels in time the suppression of other parameters of cell-mediated immunity that occurs during measles.

Antigens, Differentiation, T-Lymphocyte↗

PubMed1990

Loss of maternally acquired measles antibodies in well-nourished infants and response to measles vaccination, Peru.

Clinical, anthropometric, and serological evaluations were conducted at birth and at 3, 6, 9, and 10 months (post measles vaccination) in 34 well-nourished Peruvian infants. Seroconversion rate after measles vaccination was 94 percent. The rate of antibody loss was a direct function of birth titer; at age 9 months, all children had identical mean titers regardless of their titer at birth. Differences in maternally acquired measles antibodies at birth were important only during the first six months of life.

Aging↗

PubMed1989

Immune activation in measles.

Measles is associated with alterations in immune regulation that sometimes lead to secondary infections or autoimmune encephalomyelitis. Simultaneously, an effective measles virus-specific immune response develops. To relate immune activation to measles and its complications, we studied the spontaneous proliferation of blood mononuclear cells and circulating levels of soluble interleukin-2 receptor and CD8 T-cell antigens in 126 patients with complicated or uncomplicated measles at various stages of the disease. Spontaneous proliferation of mononuclear cells, which was present through the first week of the rash, was greater in cells from patients with measles (8787 +/- 1403 cpm) than in those from healthy children (1529 +/- 237 cpm, P less than 0.0001). Levels of soluble interleukin-2 receptor (3385 +/- 195 units per milliliter) and CD8 (4145 +/- 437 units per milliliter) were higher in patients with measles than in those with other infectious diseases (2377 +/- 440, P = 0.003; 2399 +/- 771, P = 0.0374) or in healthy children (865 +/- 138, P less than 0.0001; 1026 +/- 169, P less than 0.0001). Levels of soluble interleukin-2 receptor were elevated before the onset of the rash and remained elevated for several weeks. In contrast, levels of soluble CD8 increased only when the rash appeared, and subsided quickly. Spontaneous proliferation of mononuclear cells and levels of soluble CD8 were similar in patients with uncomplicated disease, pneumonia, or encephalomyelitis, but soluble interleukin-2 receptor levels were lower in patients with encephalomyelitis (2312 +/- 314 vs. 3455 +/- 247 units per milliliter in uncomplicated measles; P = 0.01). In patients with encephalomyelitis, cerebrospinal fluid levels of soluble CD8 (686 +/- 350 units per milliliter), but not interleukin-2 receptor (9 +/- 8.3 units per milliliter), were increased. We conclude that the proliferative phase of the immune response, as measured by the release of soluble interleukin-2 receptor, begins before the rash appears, continues for several weeks in those without complications, but does not occur within the nervous system. In contrast, the effector phase of the immune response, as measured by the release of soluble CD8, coincides with the appearance and disappearance of the rash and occurs within the nervous system during encephalomyelitis.

Adolescent↗

PubMed1989

Structural and functional division into two domains of the large (100- to 115-kDa) chains of the clathrin-associated protein complex AP-2.

The clathrin-associated protein complex 2 (AP-2 complex) is a group of proteins associated with clathrin-coated vesicles and believed to interact with cytoplasmic domains of receptors found in the plasma membrane. AP-2 was purified as an assembly of several polypeptide chains (alpha, beta, AP50, and AP17), of which only the alpha and beta chains (100-115 kDa) show significant heterogeneity. We have obtained cDNA clones for two distinct rat brain beta chains. We have also studied the domain organization of bovine brain AP-2 complexes by selective proteolysis. Results of these studies show that the alpha and beta chains have a similar two-domain organization. Their amino-terminal domains are relatively invariant whereas their carboxyl-terminal domains are variable in both sequence and length. We propose that the variable domains select receptors for inclusion in coated vesicles.

Adaptor Protein Complex 2↗

PubMed1988

Spastic paraparesis and HTLV-I infection in Peru.

Three of 6 patients with spastic paraparesis in Lima, Peru, were found to have antibodies to human T-lymphotropic virus type I (HTLV-I). Blood and cerebrospinal fluid antibodies were confirmed by Western blot analysis. Multilobulated lymphocytes in blood and cerebrospinal fluid of the index case stained with monoclonal antibodies for T-helper cells and for T10, an activation marker. Blood mononuclear cells from patients with HTLV-I-associated myelopathy showed spontaneous proliferation in culture, evidence of interleukin-2 receptors, and decreased natural killer cell activity.

Adult↗

PubMed1987

In vitro studies of the role of monocytes in the immunosuppression associated with natural measles virus infections.

Measles is associated with suppression of mitogen-induced proliferative responses. The role of monocytes in depressed responses to phytohemagglutinin during measles was assessed. Depleting peripheral blood mononuclear cells of adherent cells decreased, increased, and did not change proliferative responses in essentially equal numbers of individuals. Inhibition of prostaglandin synthesis by indomethacin significantly increased proliferation (P = 0.009) but often not to normal values. Addition of supplemental interleukin 1 had little effect. Addition of supplemental natural interleukin 2 significantly increased proliferation (P = 0.002) even in patients with very low responses. These data suggest that monocyte function is abnormal in some individuals with measles, that the abnormality is variable, and that lymphocyte response to monocyte signals is probably suboptimal as well.

Biomechanical Phenomena↗

PubMed1986

Peripheral blood mononuclear cells during natural measles virus infection: cell surface phenotypes and evidence for activation.

Peripheral blood mononuclear cells from 25 patients with measles and 13 patients with other diseases from Lima, Peru, were studied by immunocytochemical staining for cell surface antigens indicating the type of cell (Leu 4, Leu 3, T8, B1, M1, or esterase) and the state of cell activation (T10 and IL-2 receptor). Measles patients were studied during the first 2 weeks of disease and had no alteration in the proportion of cells which were positive for any subset marker or in the ratio of helper/inducer to cytotoxic/suppressor T cells compared to controls. Measles patients, however, had a greater number of cells expressing the activation antigens T10 and IL-2 receptor than controls. Incorporation of [3H]thymidine was also higher in measles patients when exogenous natural or recombinant IL-2 was added to unstimulated cultured cells. We conclude that the peripheral blood mononuclear leukocytes of patients with measles have normal proportions of helper/inducer and cytotoxic/suppressor T lymphocytes, B lymphocytes, and monocytes but that an increased number of these cells are in an activated state.

Adolescent↗

PubMed1985

Changes in plasma IgE levels during complicated and uncomplicated measles virus infections.

Plasma IgE levels were measured in 214 samples from 182 Peruvian patients with acute measles virus infections. Plasma IgE levels were significantly elevated early in infection compared to later time points. Plasma levels of IgG from the same patients rose during the same time period, whereas levels of IgA and IgM did not change. In patients with postmeasles encephalomyelitis, IgE remained elevated longer than it did in patients either with uncomplicated measles or measles complicated by pneumonia. It is proposed that the elevation of IgE is another manifestation of the altered immunoregulatory function in patients with measles.

Adolescent↗

PubMed1984

Measles encephalomyelitis--clinical and immunologic studies.

We studied 19 patients with postinfectious encephalomyelitis complicating natural measles-virus infections, and our results support the hypothesis that this demyelinating disease has a pathogenesis similar to that of experimental allergic encephalomyelitis. Early myelin destruction was demonstrated by the presence of myelin basic protein in cerebrospinal fluid, and lymphocyte proliferative responses to myelin basic protein were found in 8 of 17 patients tested. A lack of intrathecal synthesis of antibody against measles virus suggests that measles encephalomyelitis may not be dependent on virus replication within the central nervous system. Similar lymphoproliferative responses to myelin basic protein of lymphocytes from single patients with encephalomyelitis after rabies vaccine or after varicella or rubella virus infections suggest a common immune-mediated pathogenesis for the perivenular demyelinating disease that can follow the injection of neural tissues or infection by a variety of viruses.

Adolescent↗