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Biomedical subjects

A Pollak

Publications and source records attributed to A Pollak.

At least 91 records · Page 5Linked to original sources
PubMed1995

Aggravation of postcardioversion atrial dysfunction by sotalol.

OBJECTIVES: This study determined the effect of sotalol on atrial function after electrical cardioversion of atrial fibrillation. BACKGROUND: After electrical cardioversion of atrial fibrillation, the Doppler mitral A wave is often diminished, representing impaired atrial contractile function. Sotalol is an effective atrial antiarrhythmic drug with class III and beta-adrenergic blocking properties. Although the negative inotropic effect of sotalol on the ventricle is minimal in patients with normal ventricular function, it may manifest negative inotropy when ventricular function is impaired. We postulated that after cardioversion, when intrinsic atrial function is impaired, sotalol may have an adverse effect on the atrium. METHODS: Thirty-seven patients enrolled in a randomized, double-blind study of sotalol for maintenance of sinus rhythm were studied by quantitative Doppler echocardiography within 24 h of electrical cardioversion and, for those still in sinus rhythm, again at 1 month. Doppler variables (E and A wave velocities and integrals) in patients receiving sotalol were compared with those in patients receiving placebo. RESULTS: After electrical cardioversion, peak A wave velocity and A wave time-velocity integral in the 20 patients receiving placebo were reduced compared with normal values. In the 17 patients receiving sotalol (median dose 320 mg twice daily) these variables were further reduced (mean [+/- SD] peak A wave velocity 19.4 +/- 5.5 vs. 38.4 +/- 14.7 cm/s, p < 0.001 and mean A wave time-velocity integral 1.7 +/- 0.6 vs. 3.4 +/- 1.4 cm, p < 0.001, in sotalol- vs. placebo-treated patients, respectively). Early diastolic filling (E wave variables) did not differ between sotalol- and placebo-treated groups. At 1 month, five sotalol- and six placebo-treated patients remained in sinus rhythm, and A wave variables had increased for the whole group, with a greater increase in sotalol-treated patients. CONCLUSIONS: After electrical cardioversion, when atrial stunning is prominent, sotalol has a negative atrial inotropic effect. This effect may be temporary, as suggested by resolution at 1 month. Negative inotropic effects of antiarrhythmic drugs on the atrium should be considered in assessing Doppler variables of left ventricular filling.

Adult↗
PubMed1995

Ultrasensitive bioanalytical assays using time-resolved fluorescence detection.

This article reviews the use of time-resolved fluorimetric detection of lanthanide chelate luminescence as a detection method for ultrasensitive bioanalytical assays. Assay formats and detection methods, and the principle of time-resolved fluorimetric detection, are described. Detection systems, assay formats, reagents, and instrumentation for time-resolved fluorimetric detection are outlined. A review of published and commercially available immunoassays and DNA hybridization assays using time-resolved fluorimetric detection of lanthanide chelate luminescence is given.

Chelating Agents↗
PubMed1995

Time-resolved detection of lanthanide luminescence for ultrasensitive bioanalytical assays.

The principles and practice of the application of time-resolved lanthanide chelate luminescence (or fluorescence) as a detection method for ultrasensitive bioanalytical assays such as immunoassays and nucleic acid hybridization assays are reviewed. The various lanthanide chelate-based detection systems which have been developed for use in heterogeneous and homogeneous assay formats are described, including reagents, assay methods, and instrumentation, along with recent improvements in these methods. Detection systems described include those based on dissociative enhancement of lanthanide ions, direct labeling with luminescent chelates, enzyme-amplified lanthanide luminescence, lanthanide luminescence quenching, and energy transfer.

Animals↗
PubMed1995

Atrial thrombi occurring during sinus rhythm in cardiac amyloidosis: evidence for atrial electromechanical dissociation.

Thrombus formation in the left atrium is rare in patients in sinus rhythm. In three patients with extensive cardiac amyloidosis transthoracic echocardiography showed large atrial thrombi in or protruding into the body of the left atrium during sinus rhythm. Doppler studies showed no A wave on mitral inflow. Severe atrial and ventricular infiltration by amyloid may have resulted in mechanical atrial standstill with resultant thrombus formation. These findings suggest that patients with severe cardiac amyloidosis may require anticoagulation when atrial function is impaired.

Adult↗
PubMed1995

Are papillary adenomas endolymphatic sac tumors?

Papillary adenomas of the temporal bone have been considered as originating from the endolymphatic sac. The radiologic, surgical, and pathologic findings in a patient suffering from von Hippel-Lindau disease with bilateral papillary adenomas of the temporal bone cast some doubt on this site of origin. Radiologically, the center of tumor growth was at the top of the jugular bulb. Intraoperatively, the tumor was found to have reached the lateral wall of the endolymphatic sac, but the lumen was tumor-free. Both ciliated and nonciliated tumor cells were found in the resected tumor, resembling the ultrastructure of normal epithelial lining in the human mastoid. A strong positive immunohistochemical reaction for keratin and negative reactions for vimentin, glial fibrillary acidic protein, and S-100 protein in the tumor tissue of this patient are typical for middle ear mucosa. Therefore, the described papillary adenoma originated from the mucosa of the pneumatic spaces surrounding the jugular bulb, and the theory that the endolymphatic sac is the origin of all papillary-cystic tumors (adenocarcinomas) should be questioned.

Adenoma↗
PubMed1995

Cochlear vascular pathology and hydrops in otosclerosis.

Three ears with otosclerosis were found incidentally in a series of human temporal bones examined to evaluate cochlear sensorineural degeneration. Otosclerosis was identified with microdissection, surface preparation technique and transmission electron microscopy. Vascular abnormalities were present in all ears, and otosclerosis involved the cochlear endosteum extensively, mainly in the scala tympani of the basal turn. In the scala tympani of the lower half of the basal turn, shunts had formed so that venules deviated abruptly from their normal radiating course towards the spiral vein, left the scala and entered into otosclerotic foci. There was a marked loss of radiating venules in areas where otosclerosis affected the endosteum of the scala. In the pair of bones capillaries in the stria vascularis were extremely dilated, the widest being 80 microns in diameter. The third single bone from a patient with Meniere's disease had severe cochleo-saccular hydrops. Ten serially sectioned temporal bones with known otosclerosis were reviewed. Two of the bones, one of which had cochleo-saccular hydrops, displayed vascular shunts in the scala tympani and enormously dilated strial capillaries with a maximum diameter of 139 microns.

Adult↗
PubMed1995

Microparticle enzyme immunoassay (MEIA) for toxoplasma specific immunoglobulin G in comparison to the Sabin-Feldman dye test. A pilot study.

The microparticle enzyme immunoassay (MEIA) for detection of Toxoplasma specific IgG antibodies was compared to the Sabin-Feldman dye test (DT) as reference in 843 serum samples from a cohort of 757 pregnant women. The overall correlation for individual measurements was highly significant (R = 0.9446, p < 0.0001). DT and specific IgM combined allowed definition of 3 groups of patients: group 1 (no infection), group 2 (latent infection), group 3 (acute infection). A significant difference was found between the groups for the corresponding IgG values, as determined by the MEIA method, which allowed the following cut-off points to be laid down: group 1: 0-5.2 IU/ml, group 2: 5.3-187.5, and group 3: 187.6 IU/ml and higher. The validity of the cut-off points was tested in a subgroup of 57 patients who underwent serological follow-up during pregnancy. All 15 acutely- and 14 non-infected women, as well as 25 out of 28 latent infections were identified correctly. 3 latent infection were allocated falsely as acute. The threshold values presented in this report need to be confirmed in a large prospective study.

Animals↗
PubMed1995

[Direct detection of Toxoplasma gondii with polymerase chain reaction in diagnosis of fetal toxoplasma infection].

Primary infection with Toxoplasma gondii during pregnancy may affect the fetus and result in congenital toxoplasmosis. In Austria serological screening for detection of newly acquired infection during pregnancy was introduced in 1975. In this study we used polymerase chain reaction (PCR) for detection of fetal infection with Toxoplasma gondii. Amniotic fluid samples were analyzed from 11 women with serological indication of acute toxoplasmosis infection. Nine of these women had already received treatment prior to amnio-centesis and no evidence of Toxoplasma gondii DNA was detected with PCR in the respective amniotic fluid samples. Isolation of the organism by mouse inoculation was negative in these cases and follow-up serology as well as clinical examination of the infants confirmed these results. In 2 patients investigation of the amniotic fluid samples by means of PCR was positive; both women had not yet been treated at the time of amniocentesis. Our results indicate that identification of Toxoplasma gondii in amniotic fluid is a useful procedure for diagnosing or excluding fetal infection. Moreover, the current recommendations of the screening program appear to be successful in preventing congenital toxoplasmosis.

Amniotic Fluid↗
PubMed1995

[Meconium peritonitis: intrauterine follow-up--postnatal outcome].

In nine patients with meconium peritonitis prenatal ultrasonographic findings were correlated with the clinical course and outcome. Ultrasound findings included polyhydramnion (n = 4), ascites (n = 4), disseminated (n = 3) and solitary echogenic areas (n = 1), echopoor cystic areas (n = 3) and echogenic-echopoor solitary areas (n = 1). Intra-abdominal calcifications were found in five patients before delivery. Eight neonates survived and were subsequently followed up, one fetus died in utero. Four of the eight survivors required surgery, namely for meconium ileus (n = 1), perforation secondary to intestinal volvulus (n = 2) and inguinal hernia associated with prenatal rubella infection (n = 1). Three patients were healthy, one patient required drainage of pleural effusion and respirator therapy but recovered without further problems. Cystic fibrosis was diagnosed in the patient with meconium ileus. Postnatal outcome could not be predicted from the prenatal sonographic findings.

Adult↗
PubMed1994

[Ultrasound monitoring of the umbilical artery catheter. A case of a newborn infant with recurrent hypoglycemia].

Hypoglycaemia in neonates can be caused by malposition of the umbilical artery catheter (UAC). If the tip of the umbilical arterial catheter is located next to the origin of the great abdominal vessels glucose infusion is mainly directed into the coeliac trunk and superior mesenteric artery. Direct stimulation of the pancreatic gland might then result in hyperinsulinaemic hypoglycaemia. Generally, UAC position is controlled by x-ray. When using ultrasound for location of the UAC the exact topography and especially the relation of the tip of the UAC to the great vessel lumina can be documented precisely.

Blood Glucose↗
PubMed1994

Direct relationship of fetal carboxyhemoglobin with hemolysis in alloimmunized pregnancies.

Because carbon monoxide (CO) is a byproduct of heme degradation and because placental diffusing capacity of CO is limited, we hypothesized that the concentration of CO transported in fetal blood as carboxyhemoglobin (HbCO) would correlate with the severity of fetal hemolytic disease. Fetal blood was obtained by cordocentesis and HbCO was measured by gas chromatography. The two primary study groups included control fetuses (n = 26) and fetuses of Coombs-positive mothers before in utero transfusion (n = 15). Compared with controls, fetuses with hemolytic disease had higher HbCO levels (0.0111 +/- 0.0014 versus 0.0159 +/- 0.0072 fraction of total Hb, mean +/- SD, p < 0.002). In contrast, HbCO levels in simultaneously sampled maternal blood samples were not different in the control and alloimmune groups [0.0110 +/- 0.0025 (n = 20) versus 0.0115 +/- 0.0021 (n = 11)]. There was a significant inverse correlation observed between fetal HbCO and Hb concentrations in the group with hemolytic disease (r = -0.73, p < 0.002) but not in controls. In fetuses with hemolytic disease, HbCO and bilirubin were highly correlated (r = 0.88, p < 0.0001). Data from four anemic fetuses who were Coombs negative, three of whom had no evidence of hemolysis, indicated normal HbCO and normal plasma bilirubin levels. A fourth fetus with anemia had viral sepsis and elevated HbCO and plasma bilirubin levels. We conclude that elevated HbCO levels detected in fetuses of nonsmoking mothers with erythrocyte alloimmunization are likely the result of accelerated hemolysis.

Bilirubin↗