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Biomedical subjects

F Berger

Publications and source records attributed to F Berger.

At least 379 records · Page 21Linked to original sources
PubMed1975

Antigenic activity, in humans, of purified low molecular weight fractions of timothy pollen.

Small molecular weight fractions obtained from dialysis of crude timothy pollen extract were shown to carry immunogenic activity in monkeys. These fractions were sequentially purified through gel filtration with Sephadex G-10 and C-M cellulose. Monkeys immunized with these fractions produced almost eclusively skin-sensitizing antibodies which were shown to be of the IgE class, differing in antigenic specificity. These active fractions were assayed in patients allergic to timothy pollen exhibiting an allergic rhinitis. Direct skin tests and inhalation provocation tests were used. The results showed a discrepancy between the skin reactivity and the nasal response to the 3 active fractions. This result can be interpreted as heterogenity of IgE antibodies to small molecular weight fractions contained in crude timothy pollen extract, exhibiting different tissue sensitizing properties.

Animals↗
PubMedDate not supplied

Modulation of action potential duration by inhibition of the transient outward current in sheep cardiac Purkinje fibers.

In sheep cardiac Purkinje fibers concentration-dependent inhibition of transient outward current (ito) by 4-aminopyridine (4-AP, 3-1000 mumol/l) was recorded with the two-microelectrode voltage-clamp technique, and correlated effects on action potential duration measured at -70 mV (APD-70) were investigated. Half-maximal inhibition of ito-amplitude occurred at 15 mumol/l 4-AP. The drug exhibited no major effect on voltage-dependent control of inactivation but reduced the maximally available ito-current. At different activation frequencies (0.05 Hz, 0.25 Hz, 1 Hz) an equal amount of ito-current, measured as percentage of the respective control, was inhibited by 4-AP. The APD-70 was on the average increased by 4-AP (3-500 mumol/l) in a concentration-dependent manner up to 151% of control. The drug-induced prolongation, measured as percentage of the respective control, was independent of stimulation frequency (0.05 Hz, 0.25 Hz, 1 Hz). Prolongation of APD-70 was on the average more pronounced for short action potentials (APD-70 < 150 ms: 169% of reference) than for longer ones (APD-70 150-300 ms: prolongation to 117% of reference; 500 mumol/l 4-AP; 0.25 Hz stimulation rate). Few long control signals (APD-70 > 300 ms) were shortened by 4-AP. These results indicate that inhibition of ito-current by appropriate drugs will result in a reduction of inhomogeneity of action potential duration.

4-Aminopyridine↗
PubMedDate not supplied

Comparison of analgesic/sedative effect of racemic ketamine and S(+)-ketamine during cardiac catheterization in newborns and children.

The hypnotic and analgesic effect of ketamine with maintained spontaneous breathing is used for analgesic/sedative anesthesia without the need of intubation. The intention of this study was to compare the efficacy and side effects of racemic ketamine and its enantiomer S(+)-ketamine during cardiac catheterization in newborns and children. One hundred children (ages 0-11 years) were randomly assigned to groups of equal size. The differences between the racemic ketamine/midazolam and the S(+)-ketamine/midazolam groups were investigated regarding the total dosage of sedative drugs, side effects, and the awakening period. The dosage of S(+)-ketamine (2.28 mg/kg/h) was significantly lower than that needed for racemic ketamine (3.12 mg/kg/h) (p = 0.037) with an analgesic/sedative potency ratio of 1.4:1. Balloon dilatation required significantly higher dosages in both groups (p = 0.043). Significantly more patients were excluded because of ineffective analgesia/sedation or severe side effects in the racemic ketamine group. The awakening period did not show significant differences between the two groups. S(+)-ketamine proved to be a more efficient analgesic/sedative drug in newborns and children. It was shown to be useful in diagnostic and interventional procedures and allows spontaneous breathing. Moderate side effects occurred in both groups; severe side effects seemed to occur more often with the racemic solution.

Analgesics↗
PubMedDate not supplied

Challenges encountered during closure of atrial septal defects.

Since the introduction of transcatheter interventional occlusion of atrial septal defects (ASDs) by King and coworkers, the device closure has become the standard treatment of selected atrial defects. Although it has become routine for standard clinical practice, increasing knowledge of intracardiac anatomy, modification of implantation techniques, and improvements in device designs are making this treatment modality increasingly applicable to a wider range of selected patients. This report summarizes the current trends in patient selection, focusing on the anatomical limits of applicability for ASD device closure, and discusses the future possibilities. Furthermore, typical complications are described with regard to the rare erosion of the atrial roof or the aortic root. Current practice is to oversize the device if the anterior rim toward the aorta tends to be diminutive, achieving a secure position of the device around the aortic root. This and the shape memory of the device may play a major role in this serious complication and should be reconsidered. Although most interventional occlusions of interatrial defects with a device have become clinically routine, some situations remain highly challenging.

Cardiac Catheterization↗
PubMedDate not supplied

Aging and Alzheimer's disease: protease inhibitors in cerebrospinal fluid.

Recent advances suggested that proteases and their inhibitors could be implicated in the genesis and/or maturation of insoluble deposits associated with Alzheimer's disease (AD). This study was designed to measure the level of alpha 1-antichymotrypsin (ACT) and alpha 1-antitrypsin (AT) in cerebrospinal fluid (CSF) of patients with AD and nondemented humans at various ages. Our analysis failed to demonstrate a significant relationship between inhibitor content and disease. However, a positive correlation was observed between age and the ACT level for the normal control group. Such observation suggests a specific association of ACT with the mechanisms of brain aging.

Adolescent↗
PubMedDate not supplied

Small nodule detection in cirrhotic livers: evaluation with US, spiral CT, and MRI and correlation with pathologic examination of explanted liver.

PURPOSE: The purpose of this work was to evaluate the detection and characterization of nodules > or = 8 mm and small hepatocellular carcinomas (HCCs) in liver cirrhosis. METHOD: Pathologic examination and results of US, helical CT, and dynamic MRI with gadolinium were compared after orthotopic liver transplantation (OLT) of 43 cirrhotic patients. Nodules were classified as macroregenerative nodules (MRNs), borderline nodules (BNs), and HCC. RESULTS: Pathologic examination classified 69 nodules: 50 MRNs, 6 BNs, and 13 HCCs. Sensitivities of MRN, BN, and HCC detection were, respectively, for US imaging 2% (1/50), 33.3% (2/6), and 46.2% (6/13); for helical CT 2% (1/50), 50% (3/6), and 53.8% (7/13); and for MRI 42% (21/50), 50% (3/6), and 76.9% (10/13). MRI detected 21 MRNs. They presented on T1/T2-weighted images as hyperintense/hypointense (n = 8), hyperintense/isointense (n = 7), hypointense/hypointense (n = 4), hypointense/isointense (n = 1), and hypointense depicted only on echo planar imaging (n = 1). The three detected BNs were hyperintense/hypointense nodules. The 10 detected HCCs appeared hyperintense/isointense (n = 7), hyperintense/hypointense (n = 2), and hypointense/isointense (n = 1). None of the MRNs but eight HCCs and one BN were enhanced after gadolinium injection. CONCLUSION: Contrast-enhanced MRI is the most sensitive technique for detecting liver nodules. No MR signal intensity pattern characteristic of small HCCs enables differentiation from benign nodules, however. Gadolinium enhancement is the most sensitive and specific characteristic of HCC.

Adult↗