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Biomedical subjects

E Guerra

Publications and source records attributed to E Guerra.

At least 37 records · Page 2Linked to original sources
PubMed1993

Increased IL-6 gene expression and production in patients with common variable immunodeficiency.

We have studied IL-6 gene expression and production by in vitro stimulated peripheral blood mononuclear cells (PBMC) isolated from common variable immunodeficiency (CVI) patients. A strong hybridization signal for the IL-6 probe was observed in mRNA extracted from phytohaemagglutinin (PHA)- and PHA/phorbol myristate acetate (PMA)-stimulated PBMC from most of 12 CVI patients analysed. IL-6 production by PHA-stimulated PBMC from 28 CVI patients was evaluated in ELISA and found to be significantly (P < 0.0001) higher than in normal controls. IL-6 production, however, did not correlate with the lymphocyte populations examined, nor with the absolute number of monocytes. We have also showed that IL-6 was able to increase IgM secretion by several Epstein-Barr virus (EBV)-transformed cell lines derived from both normal donors and CVI patients, but it failed to modify substantially the amounts of IgM and IgG produced in vitro by PBMC derived from CVI patients and activated with pokeweed mitogen (PWM) or anti-IgM. Our data indicate that IL-6 gene expression and production is increased in CVI, but CVI cells do not respond to IL-6 with increased production of immunoglobulin.

Adolescent↗
PubMed1992

Antibody production in infants born to HIV-1-infected mothers.

Naturally occurring antibodies to polysaccharide antigens of pathogens commonly isolated from HIV-1-infected subjects were analyzed in serially collected sera of children born to seropositive mothers. Purified polysaccharides from type 14 Streptococcus pneumoniae, group C Neisseria meningitidis, type b Haemophilus influenzae, glucomannoprotein from Candida albicans and diphtheria toxoid antigens were used in an ELISA test to assess antibody levels. A significant rise of anti-pneumococcus antibody titres was noticed both in HIV-1-infected and in non-HIV-1-infected children aged 18 months or more. Anti-C. albicans and anti-group C N. meningitidis antibodies were elevated only in HIV-1-infected children older than 12 months. Anti-type b H. influenzae antibodies remained at low titres in both groups. Anti-diphtheria toxoid antibodies, analyzed as a model of humoral response to a protein antigen, were similar in both groups of HIV-1-infected and noninfected children.

Antibodies, Bacterial↗
PubMed1992

Changes in circulating B cells and immunoglobulin classes and subclasses in a healthy aged population.

The study of 87 adults of different ages, including 15 centenarians, selected for their healthy status, showed that profound changes of humoral immunity occur throughout life. In particular, a statistically significant age-related increase of the serum level of immunoglobulin classes (IgG and IgA but not IgM) and IgG subclasses (IgG1, 2 and 3, but not IgG4) was detected. A parallel age-related decrease of circulating B cells was also observed. The hypothesis of a complex derangement of B cell function and/or compartmentalization with age is put forward, together with the proposal that healthy centenarians (as representative of successful ageing) may be helpful in identifying the physiological age-related modifications of the immune system.

Adult↗
PubMed1992

[The clinical and immunological efficacy of a combination of immunoglobulins and an oral polyvalent antibacterial vaccine in recurrent respiratory infections].

Ninety patients with a history of recurrent upper and lower respiratory infections were randomized into three groups of 30 patients each. Group 1 was treated with i.m. immunoglobulins and oral polyvalent bacterial vaccine, group 2 with vaccine only, while group 3 was not submitted to prophylactic treatment. During and after prophylaxis, all three groups were evaluated for frequency of recurrent respiratory infections and the most relevant immunological parameters. In groups 1 and 2, a significant reduction of minor and major upper and lower respiratory infections was observed compared to the control group. Patients treated with Ig+vaccine or vaccine alone showed an increase of IgG2 subclasses and CD4 lymphocytes and positive changes of delayed skin tests. These findings confirm the results of previous preliminary studies which had shown the polyvalent bacterial vaccine to be useful for the reduction of recurrent infections of the respiratory tract, especially during the winter. Further studies will have to be carried out in order to identify the precise mechanism by which antigen stimulation with the oral vaccine improves the immunological response of the respiratory tract.

Administration, Oral↗
PubMed1991

The use of biosensors in pacemaker technology: experience with a ventricular rate responsive pacemaker.

Ten elderly patients each had a ventricular rate responsive pulse generator (Activitrax) placed in them to help correct severe conduction abnormalities; none had suspected ischemic heart disease. The pulse generator was programmed to a maximal pacing rate of 125 ppm, a medium activity threshold, and a rate response of 6. Six weeks after implantation of the pulse generator, the patients were evaluated before exercising and again when the pacing rate reached 125 ppm. The evaluation protocol included an M-mode echocardiogram from which the following measurements were taken: the left ventricular end-diastolic volume (EDV), the end-systolic volume (ESV), the ejection fraction (EF), and the peak systolic pressure/end-systolic volume (PSP/ESV). The numerical values were recorded, calculated, and compared statically with the following results: the EDV increased from 91 +/- 10 to 125 +/- 20 cc (p less than .05); the ESV decreased from 64 +/- 10 to 24 +/- 6 cc (p less than .005); the EF increased from 41 +/- 5 to 61 +/- 10% (p less than .05); and the PSP/ESV ratio increased from 1.70 +/- 1 to 4.10 +/- 2 mm Hg/cc (p = 10). Also, during the maximal pacing rate, the septum of all patients showed paradoxical septal motion. All patients in our study have been asymptomatic and have shown an increase in their exercise capacity. We conclude that during exercise the left ventricular function ins influenced more by heart rate than by AV synchrony, as indicated by an elevated EDV in most patients.

Aged↗
PubMed1990

Antibacterial polysaccharide antibody deficiency after allogeneic bone marrow transplantation.

Allogeneic bone marrow-engrafted adults immunized with meningococcal types A and C and pneumococcal type 14 polysaccharide antigens showed only low antibody titers of the IgM class, no antibody titers of the IgG or IgA classes, and no bactericidal activity in vitro. The analytical isoelectrofocusing showed the appearance of a restricted pattern of clonotypes in a minority of subjects. These observations are consistent with the hypothesis that B cells in bone marrow transplant patients express some characteristics of neonatal B cells and suggest that polysaccharide-protein conjugates, rather than isolated polysaccharide, might be utilized in the setting of bone marrow transplantation.

Adult↗
PubMed1989

Effects of parent presence on children's reactions to injections: behavioral, physiological, and subjective aspects.

Observed 47 children ranging in age from 13 months to 7 years 9 months receiving injections as part of a regular visit to a pediatric clinic. Twenty-three children were randomly assigned to a condition with parent (mainly mothers) present and 24 to a condition with parent absent. During the medical procedure, the child's reactions were observed via videotape (for later behavioral coding) and physiological recording (to measure heart rates). Following the injection, data were collected on the child's preference of condition (either parent present or parent absent) for future injections. Older children (but not younger ones) showed significantly more behavioral distress when the parent was present. However, the oldest children's preference of condition for future injections was overwhelmingly that of parent present (86%).

Arousal↗
PubMed1987

Left ventricular function in adults with atrial septal defect.

Sixteen patients with secundum atrial defect were catheterized giving emphasis to the analysis of the left ventricle at end systole and mid-ejection. The mean ejection fraction of the group was subnormal 57 + 8% when compared with 30 normal patients (71 + 109) P less than .005. Eight patients showed elevated end-diastolic volumes (156 + 10cc) when compared to our normal group (95% + 10cc) P less than .005. A total of 32 hypokinetic and 35 tardokinetic areas were found. Eight patients were restudied after nitroglycerin (0.4 mg sublingually) with an improvement in the ejection fraction from 54% to 70% (P less than .005) and normalization of most of the hypokinetic areas. No correlation was found between total ejection fraction or total systolic wall motion and the shunt size. Probably these left ventricular wall motion abnormalities are primary and not due to the shunt size.

Adolescent↗
PubMed1984

Correlation between ventilation and brain blood flow during sleep.

The relationships between brain blood flow (BBF) and ventilation (VI) were studied during sleep in 13 goats. Unilateral BBF was continuously measured with an electromagnetic flow probe; total and regional BBF were assessed by the radioactive microsphere technique in four animals. Interacting changes in VI and BBF occurred during both slow wave (SWS) and rapid eye movement (REM) sleep. During SWS, significant decreases in VI and increases in arterial PCO2 occurred compared to wakefulness. BBF during SWS correlated linearly with arterial CO2 tension (PaCO2); nd the relationship was similar to that for awake goats breathing CO2. During REM sleep, VI was significantly less than both the awake (W) and SWS states due principally to a decrease in tidal volume. BBF during REM sleep was significantly and substantially increased compared with both the W and SWS states; this increase was shared by all brain areas. The increase in BBF during REM sleep was greater than that predicted from changes in PaCO2. In five goats provided with chronic sagittal sinus fistulae, arteriovenous oxygen difference was measured in separate studies and found to be significantly lower during REM sleep compared with W; brain O2 consumption was similar in magnitude in the REM and W states. Thus, the high BBF of REM sleep was also unexplained by an increase of brain metabolic activity. We conclude that, during SWS, increases in BBF are explained by hypoventilation and hypercapnia. In contrast, during REM sleep, BBF is substantially in excess of that expected from PaCO2 or brain metabolism. It is postulated that this excess of BBF during REM sleep could reduce the central chemoreceptor pH relative to that present in SWS. The combination of reduction of sensitivity to CO2 and lower tissue PCO2 during REM sleep makes it likely that the output of the central chemoreceptors during this state is less than that during SWS and wakefulness. This may contribute to the low tidal volume and respiratory irregularities of this sleep period.

Animals↗