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Biomedical subjects

A Pollak

Publications and source records attributed to A Pollak.

At least 55 records · Page 3Linked to original sources
PubMed2000

Survival after intrauterine myocardial infarction: noninvasive assessment of myocardial perfusion with 99mTc-Sestamibi scintigraphy.

Survival after severe intrauterine myocardial infarction has not been reported previously. We describe the course of a neonate with a structurally normal heart, who presented with cardiogenic shock at birth due to intrauterine myocardial infarction with a huge ventricular aneurysm. Myocardial perfusion was assessed noninvasively by means of 99mTc-Sestamibi, a radiopharmaceutical agent recently introduced in nuclear cardiology to avoid repeated coronary angiography. The patient survived with improved cardiac function and normal neurodevelopmental outcome.

Adult↗
PubMed2000

Preterm infants with low immunoglobulin G levels have increased risk of neonatal sepsis but do not benefit from prophylactic immunoglobulin G.

OBJECTIVE: In a prospective, randomized, placebo-controlled, multicenter study, we evaluated the prevention of neonatal infections with intravenous immunoglobulin G (IVIgG) prophylaxis for preterm infants (gestational age <33 weeks) with umbilical cord blood IgG levels < or =4 g/L. STUDY DESIGN: Intravenous IgG or placebo (albumin), 1 g/kg body weight, was given on days 0, 3, 7, 14, and 21 to 81 infants with umbilical cord blood IgG levels < or =4 g/L: (1) IVIgG group, n = 40, mean (SD) gestational age 27.5 (2.2) weeks and birth weight 1.06 (0.39) kg; (2) placebo group, n = 41, mean (SD) gestational age 27.7 (2.5) weeks and birth weight 1.13 (0.38) kg. Infants with umbilical cord blood IgG levels >4 g/L (n = 238) served as a separate comparison group. Neonatal infections according to European Society of Pediatric Infectious Disease criteria were monitored until 28 days of life. RESULTS: Infants with IgG levels < or =4 g/L at birth who received IVIgG had no significant reduction in infectious episodes or mortality rate when compared with those given placebo. However, infants with a serum concentration of IgG >4 g/L at birth had significantly fewer infectious episodes (culture-proven sepsis) than infants with low serum concentrations of IgG (< or =4 g/L) when compared at the same gestational ages (26 to 29 weeks, P <.003). CONCLUSIONS: Prophylactic immunotherapy with IVIgG did not improve the immune competence in preterm infants with low serum IgG concentrations at birth. We speculate that a spontaneously high serum IgG concentration at birth reflects placenta function and is an indicator of a more mature immune system capable of protecting the preterm infant against severe neonatal infections.

Cross Infection↗
PubMed2000

Ethnic differences in the frequency of the C677T mutation in the methylenetetrahydrofolate reductase (MTHFR) gene in healthy Israeli populations.

Hyperhomocysteinemia is an independent risk factor for arteriosclerotic vascular disease. It can result from deficiencies of co-factors required for homocysteine metabolism and/or from genetic disorders of its metabolism. The association between the C677T mutation in the methylenetetrahydrofolate reductase (MTHFR) gene and vascular disease is controversial, and may be affected by ethnic origin. A unique feature of the Israeli population is its ethnic diversity. The aim of this study was to study the frequency of the C677T MTHFR mutation in healthy Israeli ethnic groups. The frequency of the mutation was determined in 897 young healthy Jewish and Muslim Arab Israelis of eight different ethnic groups. Marked ethnic differences in the frequency of mutant homozygotes were found, ranging from 2% in Yemenite Jews, 4% in Sephardic Jews, 9% in Oriental Jews, 10% in Muslim Arabs, 16% in North African Jews, and 19% in Ashkenazi Jews. The frequency of mutant homozygotes was significantly higher in Ashkenazi Jews compared to Yemenites Oriental Jews, Sephardic Jews, and Muslim Arabs (chi2 = 12.35p < 0.001, chi2 = 8.17p = 0.004, chi2 = 6.04p = 0.01, chi2 = 6.54 p = 0.01, respectively). Our findings demonstrate the need for matching ethnic background in patients and controls when studying the association between the C677T MTHFR mutation and any disease.

Adolescent↗
PubMed2000

The C677T mutation in the methylenetetrahydrofolate reductase (MTHFR) gene and vascular dementia.

OBJECTIVE: To determine the association between the C677T mutation in the methylenetetrahydrofolate reductase (MTHFR) gene and vascular dementia in Ashkenazi and non-Ashkenazi Jews. DESIGN: A case-control study. SETTING: Nursing homes in Jerusalem, Israel. PARTICIPANTS: Two hundred fifty nine Jewish people of Ashkenazi and non-Ashkenazi origin, older than age 70, who have vascular dementia (VD) (n = 85), Alzheimer's disease (AD) (n = 92), and who are cognitively intact (n = 82) with no clinical evidence of atherosclerotic vascular disease. MEASUREMENTS: The frequencies of the mutant allele (T allele) and homozygotes for the C677T MTHFR mutation (T/T genotype). The total plasma homocysteine (tHCT) level in 75 subjects. RESULTS: There were no significant differences in the frequencies of the T/T genotype or T allele among VD, AD, and cognitively intact older people of the same ethnic origin (0.15, 0.19, 0.25 T/T genotype and 0.42, 0.46, 0.47 T allele in Ashkenazi; 0.08, 0.06, 0.10 T/T genotype and 0.28, 0.32, 0.33 T allele in non-Ashkenazi with VD and AD, and in cognitively intact older people, respectively). The relative risk of VD associated with the T/T genotype versus the C/C genotype was 0.62 (95% CI, 0.19-1.19) in Ashkenazi and 0.65 (95% CI, 0.11-3.7) in non-Ashkenazi, respectively. The relative risk of AD associated with the T/T genotype was 0.85 (95% CI, 0.29-2.45) in Ashkenazi and 0.62 (95% CI, 0.1-4.3) in non-Ashkenazi, respectively. The frequencies of mutant homozygotes and allele were significantly higher in Ashkenazi than in non-Ashkenazi Jews (19.9% vs 7.5% T/T genotype, chi2 = 6.2, P = .01, 0.45 vs 0.31 T allele, chi2 = 9.77, P = .002 in Ashkenazi vs non-Ashkenazi, respectively). There were no differences in mean tHCT concentration among VD, AD, and cognitively intact older people. CONCLUSIONS: The MTHFR C677T is not associated with an increased risk of vascular dementia or Alzheimer's disease. The frequency of the mutation is significantly higher in Ashkenazi compared with non-Ashkenazi Jews.

Aged↗
PubMed2000

Transvenous pacemaker leads do not worsen tricuspid regurgitation: a prospective echocardiographic study.

Limited prospective data are available regarding the influence of pacemaker leads on tricuspid valve function. To examine the true incidence of these complications, 35 patients were prospectively examined by two-dimensional and Doppler echocardiography before and after implantation of either a permanent pacemaker or an automatic implantable cardioverter-defibrillator. Of the 35 patients imaged preoperatively, the amount of tricuspid regurgitation (TR) was judged as normal or trivial in 15 (43%), mild in 10 (29%), moderate in 8 (23%), and severe in 2 (6%). Following electrode implantation, TR was noted to be normal or trivial in 13 (38%), mild in 15 (48%), moderate in 6 (17%) and severe in 1 (3%). We conclude that implantation of permanent right ventricular electrodes is not usually associated with an acute worsening of tricuspid regurgitation in most patients.

Aged↗
PubMed2000

Outcome of very-low-birth-weight infants at 1 and 2 years of age. The importance of early identification of neurodevelopmental deficits.

The developmental and neurologic outcome of very-low-birth-weight infants (n=76) at 1 and 2 years, corrected for postconceptional age, and variables predicting outcome were assessed. At 1 year 24% of tile children were neurologically normal and at 2 years 61%. Developmental status was evaluated by use of the Griffiths Developmental Scales. The rate of cognitively normal children remained constant (58% at 1 year and 59% at 2 years) indicating that developmental status at 1 year was predictive for the second year. This early period is important, therefore, for the identification of developmental deficits and for establishing early, adequate interventions.

Austria↗
PubMed1999

Prenatal diagnosis of congenital toxoplasmosis: a multicenter evaluation of different diagnostic parameters.

OBJECTIVE: Our purpose was to evaluate different methods of diagnosing congenital toxoplasmosis prenatally by amniocentesis and cordocentesis. STUDY DESIGN: In a retrospective multicenter study, we investigated consecutive women who had seroconversion for Toxoplasma gondii during pregnancy and who underwent either amniocentesis or cordocentesis or both to obtain a prenatal diagnosis of fetal toxoplasmosis. Data were obtained from 122 patients recruited in 6 different European Toxoplasma reference centers. Infants born to these mothers were followed up until 1 year of age to confirm or exclude congenital toxoplasmosis. Sensitivity, specificity, positive predictive value, and negative predictive value were measured for the following parameters: (1) detection of the parasite in amniotic fluid by mouse inoculation, (2) detection of the parasite in amniotic fluid by in vitro cell culture, (3) detection of Toxoplasma deoxyribonucleic acid in amniotic fluid by a polymerase chain reaction assay, (4) detection of the parasite in fetal blood by mouse inoculation, (5) detection of specific immunoglobulin M antibodies in fetal blood, and (6) detection of specific immunoglobulin A antibodies in fetal blood. RESULTS: The polymerase chain reaction test performed on amniotic fluid had the highest level of sensitivity (81%) and also a high level of specificity (96%). The combination of the polymerase chain reaction test and mouse inoculation of amniotic fluid increased sensitivity to 91%. The sensitivity of immunoglobulins M and A in fetal blood was 47% and 38%, respectively. In congenitally infected fetuses a negative correlation was observed between positive serologic parameters and gestational age at the time of maternal infection and at prenatal diagnosis. CONCLUSION: Congenital toxoplasmosis is best predicted by prenatal examination with the combination of T gondii polymerase chain reaction and mouse inoculation of amniotic fluid. The role of cordocentesis in the diagnosis of congenital toxoplasmosis is limited.

Amniocentesis↗
PubMed1999

Diagnosis of congenital toxoplasmosis in the neonatal period: A multicenter evaluation.

OBJECTIVE: To evaluate different laboratory tests used to diagnose congenital toxoplasmosis in the neonatal period. STUDY DESIGN: A retrospective multicenter study of 294 pregnant women who experienced seroconversion for Toxoplasma gondii and subsequently delivered live-born infants. Fetal infection was assessed via specific IgM and IgA antibodies (cord and neonatal blood) and detection of T gondii in placenta and cord blood by mouse inoculation. RESULTS: Ninety-three (32%) of the 294 infants were congenitally infected. The sensitivity of IgA in cord blood and in neonatal blood was 64% and 66%; the sensitivity of IgM was 41% and 42%, respectively. Mouse inoculation of the placenta and cord blood had sensitivities of 45% and 16%. Positive results of the serologic tests in congenitally infected children correlated significantly with the gestational age at the time of maternal infection but was not significantly influenced by the administration of specific antiparasitic treatment during pregnancy. CONCLUSION: Specific T gondii IgA antibody is a more sensitive test than IgM for detecting congenital toxoplasmosis in the neonatal period. The overall specificity is better for serologic tests performed on neonatal blood than for those on cord blood. Neonatal screening with IgM or IgA antibodies will not detect the majority of children with congenital toxoplasmosis when the maternal infection occurred before the 20th week of pregnancy.

Anti-Bacterial Agents↗
PubMed1999

A centrifugal pump driven tidal flow extracorporeal membrane oxygenation system tested with neonatal mock circulation.

In 1993, Chevalier published his experiences with tidal flow venovenous extracorporeal membrane oxygenation (ECMO) featuring a single lumen cannula, non-occlusive roller pump, and alternating clamps. Using a neonatal mock circulation (NMC), which enables different hemodynamic states for neonatal ECMO research, the tested hypothesis was that it is possible to create a centrifugal pump driven tidal flow neonatal venovenous ECMO system. Additionally, the resulting hemodynamic effects in a condition of circulatory impairment were investigated. The ECMO circuit tested was assembled using a pediatric centrifugal pump head, a distensible reservoir, and a rotary clamp separating drainage from the injection phase. Using the NMC, end tidal volumes, mock circulation flow, and arterial and venous pressures were measured at different pump speeds after the drainage and injection phases. Effective venovenous ECMO flow (evvEF) was calculated. Mock circulation baseline values (ECMO clamped) were compared to values during tidal flow ECMO. At 3,000 rpm, a centrifugal pump speed of 75 ml/kg/min evvEF was reached, and it increased with higher pump speeds. At this point, the end tidal mock circulation flow (representing cardiac output) after drainage differed significantly from that during the injection phase (p < 0.01) but not from the baseline value. The end tidal arterial and venous pressures after the drainage phase were found to be significantly decreased compared to the baselines (p < 0.01). In conclusion, a centrifugal pump driven tidal flow venovenous ECMO system can be created enabling sufficient tidal volumes. Tested in the described NMC simulating posthypoxic circulatory impairment, significant hemodynamic effects could be demonstrated. Animal experiments for confirmation are necessary.

Analysis of Variance↗
PubMed1999

Intravenous prostacyclin mitigates inhaled nitric oxide rebound effect: A case control study.

Although extracorporeal membrane oxygenation (ECMO) improves oxygenation, pulmonary vascular resistance may be increased due to endothelial function impairment. Inhaled nitric oxide (iNO) is increasingly used for treatment of pulmonary hypertension after surgical repair of congenital heart defects, with or without ECMO. One of the main complications of its application is deterioration of oxygenation following withdrawal of iNO. To test whether intravenous prostacyclin applied prior to and during iNO withdrawal can mitigate this rebound effect, we conducted a retrospective case control study. The rebound effect was defined as a 5% decrease of oxygenation saturation within 4 h after iNO withdrawal. Twelve children suffering from pulmonary hypertension (2 after ECMO) and treated with iNO received 10 ng/kg/min prostacyclin intravenously 24 h prior to iNO withdrawal (Group 1). Twelve children treated with iNO (3 after ECMO) who received no prostacyclin prior to iNO withdrawal were matched as controls. The rebound effect occurred in 1 out of 12 children in Group 1 and in 8 out of 12 children in Group 2 (p = 0. 0039). We conclude that application of intravenous prostacyclin prior to and during iNO withdrawal may be able to mitigate the rebound effect.

Administration, Inhalation↗
PubMed1999

Proposed entry criteria for postoperative cardiac extracorporeal membrane oxygenation after pediatric open heart surgery.

While extracorporeal membrane oxygenation (ECMO) is being used increasingly after pediatric cardiac surgery, criteria are lacking for initiating ECMO after bypass weaning. To develop clinically useful ECMO entry criteria based on parameters readily available, children were examined at postoperative pediatric intensive care unit (PICU) admission. Using hospital mortality as the primary outcome, univariate and multiple logistic regressions were performed to estimate the predictive value of clinical (age, weight, and diagnosis) and laboratory (arterial blood pressure, pH, lactate, creatine kinase, and arterial and central venous oxygen saturation [ScvO2]) variables. Data from 218 children over a 2 year period were analyzed retrospectively. Univariate regression demonstrated that age, weight, diagnosis, blood pressure, venous and arterial saturation, and lactate were significantly associated with postoperative mortality (p < 0.05). In multiple regression, ScvO2 and lactate level were found to be independent predictors and were used in a predictive model (ScvO2 odds ratio: 2.03-828.6, p = 0.016) (lactate odds ratio: 1.58 -4.20, p = 0.0002) (R2 = 0.70). Applying an 80% risk of mortality to establish entry criteria as in neonatal ECMO, PICU admission values of lactate > 70 mg/dl if ScvO2 < 60% or lactate >163 mg/dl if ScvO2 > 60% are proposed to serve as postoperative ECMO entry criteria if bypass weaning has been possible but is followed by low cardiac output.

Adolescent↗
PubMed1999

Central venous catheter mechanical irritation of the right atrial free Wall:A cause for thrombus formation.

Thromboembolism is a major complication of long-term central venous catheter, usually associated with catheter or venous occlusion. Intracavitary right atrial thrombosis is currently considered to result from line-tip thrombosis extension. We report three adult patients in whom repeated mechanical trauma to the right atrial wall was probably the main mechanism. Transesophageal echocardiography revealed back and forth movement of the central catheter into a thrombus attached to the right atrial wall, thus suggesting a mechanism of catheter-associated thrombus formation, not previously visualized or suggested. Catheter removal and anticoagulation administration were undertaken with an uneventful clinical course and almost complete disappearance of the thrombi on transesophageal echocardiography follow-up.

Adult↗
PubMed1999

Objective evaluation of normal facial function.

The aim of this investigation was the assessment of normal facial movements using the objective computer-assisted OSCAR method. Computerized black-and-white video images of 20 healthy volunteers were recorded with the face at rest, maximal wrinkling of the forehead, forced eye closure, and forced smiling. The mean regional symmetry index was found to be 91% (SD 6%; range 80% to 99%) for wrinkling of the forehead, 93% (SD 5%; range 82% to 100%) for forced eye closure, and 91% (SD 5%; range 79% to 98%) for maximal smiling. Clinical weighting gave a global symmetry index of 92% (SD 3%; range 88% to 96%). The presented results show that the physiological dynamic asymmetry of the normal face is 7% to 9%. No dominant facial side could be found. The comparison of the results obtained with the OSCAR method with those of the subjective House-Brackmann and Fisch grading systems showed that the physiological asymmetry of facial movements can only be accurately determined with a computer-assisted objective method.

Adult↗
PubMed1999

Heart rate variability during chronic hemodialysis and after renal transplantation: studies in patients without and with systemic amyloidosis.

The present study was undertaken to compare heart rate variability (HRV) values in patients on maintenance hemodialysis with no evidence of ischemic or hypertensive heart diseases to those of age- and gender-matched healthy individuals and those of patients after renal transplantation. To assess the effects of a common confounding factor, HRV values were also determined in patients with systemic amyloidosis, in chronic hemodialysis, and after successful renal transplantation. Spectral analyses of RR intervals from continuous electrocardiogram recordings were performed to quantify ultra low frequency, very low frequency, low frequency, and high frequency powers. HRV determinations were all significantly reduced in uremic patients undergoing hemodialysis compared with the healthy control subjects, especially in those with systemic amyloidosis. Renal transplantation normalized HRV in most patients; HRV, however, remained reduced in isolated amyloidosis patients with cardiac or adrenal involvement. HRV circadian day/night differences were preserved in hemodialysis patients and after renal transplantation in those without amyloidosis but not in those with amyloidosis. These data suggest that reduced HRV in chronic hemodialysis patients may precede other manifestations of cardiovascular disease. In uremic patients with amyloidosis, a more severe form of autonomic failure may occur. Successful transplantation corrects HRV abnormalities in most patients, suggesting that the autonomic dysfunction of uremia is caused by humoral factors reversed by the normalization of the renal function.

Adolescent↗
PubMed1999

In vivo gammadelta T cell priming to mycobacterial antigens by primary Mycobacterium tuberculosis infection and exposure to nonpeptidic ligands.

BACKGROUND: The recognition of phosphorylated nonpeptidic microbial metabolites by Vgamma9Vdelta2 T cells does not appear to require the presence of MHC molecules or antigen processing, permitting rapid responses against microbial pathogens. These may constitute an important area of natural anti-infectious immunity. To provide evidence of their involvement in immune reactivities against mycobacteria, we measured the responsiveness of peripheral blood Vgamma9Vdelta2 T cells in children with primary Mycobacterium tuberculosis (MTB) infections. MATERIALS AND METHODS: Peripheral blood mononuclear cells from 22 children with MTB infections and 16 positivity of tuberculin (PPD)-negative healthy children were exposed to nonpeptidic antigens in vitro and the reactivity of the Vgamma9Vdelta2 T cell subset with these antigens was determined using proliferation and cytokine assays. Also, responses of gammadelta T cells from rhesus monkeys stimulated with phosphoantigens in vivo were measured. RESULTS: The Vgamma9Vdelta2 T cell responses were highly increased in infected children in comparison with age-matched controls. This augmented Vgamma9Vdelta2 T cell reactivity subsided after successful antibiotic chemotherapy, suggesting that persistent exposure to mycobacterial antigens is required for the maintenance of gammadelta T cell activation in vivo. The in vivo reactivity of Vgamma9Vdelta2 T cells to phosphoantigens was also analyzed in a rhesus monkey model system. Intravenous injections of phosphoantigens induced an activated state of simian Vgamma9Vdelta2 T cells which decreased after 2 months, i.e., with a time course similar to that seen in MTB-infected children. CONCLUSIONS: The increased reactivity of Vgamma9Vdelta2 T cells to phosphoantigens appears to be dependent on constant antigenic exposure. Consequently, the assessment of Vgamma9Vdelta2 responses may be useful for monitoring the efficacy of antimycobacterial therapies.

Animals↗