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Biomedical subjects

A Piotrowska

Publications and source records attributed to A Piotrowska.

18 recordsLinked to original sources
PubMed2002

Ising quantum Hall ferromagnet in magnetically doped quantum wells.

We report on the observation of the Ising quantum Hall ferromagnet with Curie temperature T(C) as high as 2 K in a modulation-doped (Cd,Mn)Te heterostructure. In this system field-induced crossing of Landau levels occurs due to the giant spin-splitting effect. Magnetoresistance data, collected over a wide range of temperatures, magnetic fields, tilt angles, and electron densities, are discussed taking into account both Coulomb electron-electron interactions and s-d coupling to Mn spin fluctuations. The critical behavior of the resistance "spikes" at T-->T(C) corroborates theoretical suggestions that the ferromagnet is destroyed by domain excitations.

Journal Article↗
PubMed1977

Allergy testing: comparison of skin and in vitro tests of allergic reagin.

Skin tests have been used for many years to detect reaginic antibodies in the investigation of allergic patients. Recently in vitro assays of allergic reagins, including the radioallergosorbent test (RAST) and the rat mast cell test (RMCT) have become available. A comparison of the clinical usefulness of these tests suggested that skin tests and the RAST are of comparable diagnostic accuracy and reliability. The RMCT was found to be poorly reproducible and unreliable. For routine cases skin tests should continue to be the procedure of choice. The RAST may reasonably be used when skin tests are unreliable, impractical or contraindicated. The RAST may also be helpful in some cases in resolving discrepancies between skin test results and the clinical history.

Animals↗
PubMedDate not supplied

[The value of the head-up tilt table test for with unexplained syncope in children and young adolescents].

UNLABELLED: Syncope occurs in about 15% of children and young adolescents. The diagnosis of syncope of unknown origin is frequently difficult. In 1986, Kenny et al. introduced the Head-up Tilt Table Test (HUT), which enables to reproduce syncope. The aim of the study was to evaluate HUT in diagnosis of syncope in children and young adolescents. Ninety five children and young adolescents (57 females, 38 males, age range 7-18 years) with recurrent syncope of unexplained etiology were referred for HUT. The study group was divided into two subgroups: A--with history consistent with vasovagal syncope (VVS) and B--with non-characteristic symptoms for VVS. HUT was performed according to the Westminster protocol. The patient was tilted at 60 degree for 45 min. or until syncope occurred. Positive response to HUT was 36%. Negative outcome occurred in 59%. Non-diagnostic HUT was observed in 5%. The vasodepressive type of VVS was recognised in 35%, cardioinhibitory in 12% and mixed in 53%. In group A positive response of HUT occurred in 65% of pts., negative in 31%. In group B positive HUT was observed in 4% of pts. and negative in 89%. CONCLUSIONS: 1. In children and young adolescents head-up tilt test is a very useful diagnostic method. 2. In patients referred for the head-up tilt test the history of syncope should be taken into consideration.

Adolescent↗
PubMedDate not supplied

Effects of site and size of septum lesions on feeding and drinking behavior in the cat.

Lesions involving most of the septum caused in cats a reduction in drinking milk and eating cereal. Only the lesions involving a part of the posterior one-third of the septum increased consumption of milk and solid food. Changes of drinking behavior were usually more pronounced and permanent. In some cases the normal ratio of drunk fluids to solid food eaten was disturbed, that is either the amount of the consumed milk or cereal changed; in some animals these changes were more or less parallel. Increase or abolition of effects caused by lesions involving areas playing a similar or an opposite role in these functions were observed very often. This indicates how important it is in such investigations to produce precise lesions of strictly determined site and size.

Animals↗