Plasma exchange: a controlled study of the effect in patients with Raynaud's phenomenon and scleroderma

Six female patients with stage I and II vascular scleroderma and Raynaud's phenomenon were treated with plasma exchange and placebo plasma exchange. Placebo exchange consisted of the return of the patient's own separated plasma. No consistent long-term objective improvement was demonstrated in patients treated with either plasma exchange or placebo plasma exchange. Immediate increases in pulse volume, digital blood pressure, and skin temperature occurred in some patients with both procedures. Mechanisms of change remain unexplained, and further study is warranted.     

Measurement of anti-IgA antibodies by a two-site immunoradiometric assay

To enable the detection of IgG class, anti-IgA antibodies (IgG-aIgA) and to investigate the possible occurrence of IgE class, anti-IgA antibodies (IgE-aIgA), we developed a solid phase immunoradiometric assay (IRA), which uses purified IgA coupled covalently to microcrystalline cellulose as an immunosorbent. Radiolabeled, Fc specific anti-IgG and anti-IgE antibodies were used to detect specific aIgA after incubation of test sera or controls with the immunosorbent. IgG-aIgA were detected by the IRA in 100 and 67 per cent of control sera with class specific and limited specificity aIgA. The IRA was sensitive to approximately two ng of class specific IgG-aIgA. IgG-aIgA also were detected by IRA in 7.9 per cent of sera from patients with urticarial transfusion reactions and 73 per cent of sera from patients with ataxia telangiectasia and IgA deficiency. Sera from 50 normal blood donors did not have detectable IgG-aIgA. Tests for IgE-aIgA were negative in all cases, including control sera with class specific IgG- aIgA. We conclude that the IRA is a sensitive and reproducible method for detection of class specific and limited specificity IgG-aIgA, and that IgE-aIgA do not mediate urticarial transfusion reactions.     

Use of short tandem repeats loci to study the genetic structure of several populations from Zulia State, Venezuela.

Genetic relationships between populations can be studied by comparing genotypic and allelic similarities. This investigation aims to demonstrate that selected autosomal microsatellite markers could be used to study the genetic structures of different populations living in northwest Venezuela, in Zulia State. Seven autosomal systems (CSF1PO, TPOX, TH01, vWA, D7S820, D13S317, and D5S818) were tested by PCR in a multiplex format on 688 different chromosomes from unrelated individuals living in Maracaibo, "Isla de Toas," and "San José de Heras," and from two Amerindian populations from the "Sierra de Perijá," Barí' and Yukpa. Allele frequencies, Hardy-Weinberg equilibria, genetic distances, phylogenetic trees, and ethnic admixtures were estimated. The study shows the existence of a clear genetic difference among these populations in accordance with their historic evolution. The populations of Maracaibo and "Isla de Toas" showed a triracial origin, with a large European contribution, followed by an Amerindian component and a small African component. The indigenous groups, Barí' and Yukpa, showed exclusively an Amerindian component, and "San José de Heras" showed only an African component. These results indicate that microsatellite markers are useful for molecular anthropology in a regional and worldwide context and provide important genetic information about contemporary populations of Venezuela.     

Ovarian transplantation between monozygotic twins discordant for premature ovarian failure

Monozygotic 24-year-old twins presented with discordant ovarian function. One had had premature ovarian failure at the age of 14 years, whereas her sister had normal ovaries and three naturally conceived children. After unsuccessful egg-donation therapy, the sterile twin received a transplant of ovarian cortical tissue from her sister by means of a minilaparotomy. Within three months after transplantation, the recipient's cycles resumed and serum gonadotropin levels fell to the normal range. During the second cycle, she conceived, and her pregnancy progressed uneventfully. At 38 weeks' gestation, she delivered a healthy-appearing female infant.     

EEG evidence for mirror neuron dysfunction in autism spectrum disorders

Autism spectrum disorders (ASD) are largely characterized by deficits in imitation, pragmatic language, theory of mind, and empathy. Previous research has suggested that a dysfunctional mirror neuron system may explain the pathology observed in ASD. Because EEG oscillations in the mu frequency (8-13 Hz) over sensorimotor cortex are thought to reflect mirror neuron activity, one method for testing the integrity of this system is to measure mu responsiveness to actual and observed movement. It has been established that mu power is reduced (mu suppression) in typically developing individuals both when they perform actions and when they observe others performing actions, reflecting an observation/execution system which may play a critical role in the ability to understand and imitate others' behaviors. This study investigated whether individuals with ASD show a dysfunction in this system, given their behavioral impairments in understanding and responding appropriately to others' behaviors. Mu wave suppression was measured in ten high-functioning individuals with ASD and ten age- and gender-matched control subjects while watching videos of (1) a moving hand, (2) a bouncing ball, and (3) visual noise, or (4) moving their own hand. Control subjects showed significant mu suppression to both self and observed hand movement. The ASD group showed significant mu suppression to self-performed hand movements but not to observed hand movements. These results support the hypothesis of a dysfunctional mirror neuron system in high-functioning individuals with ASD.