Continuous Biofeedback and Discrete Posttrial Verbal Feedback in Frontalis Muscle Relaxation Training

During training to relax the frontalis muscle, continuous biofeedback (BF) was compared to discrete verbal feedback (VF) delivered immediately after each trial. Both feedback modalities were based on frontalis electromyographic (EMG) activity. Training consisted of 3 consecutive daily session-each comprised of 3 baseline (nonfeedback) trials followed by 10 training trials of 128 see. The presence or absence of the two informationally positive feedback modalities were combined factorially to define four training conditions: BF + VF, NO BF + VF, BF + NO VF, and NO BF + NO VF. Results indicated that while VF alone facilitated muscle relaxation, BF was clearly prepotent ill effecting consistent decreases in EMG activity both across trials and days of training. Additionally, the facilitating effect of BF transferred to nonfeedback trials while VF did not affect performance on nonfeedback trials. Finally, accuracy of self-evaluations of performance on a trial by trial basis was markedly improved by BF, while VF improved accuracy only for trials having a very large absolute difference between levels of EMG activity. Ss receiving no feedback neither reduced muscle tension during training not were able to evaluate their performance accurately even when large absolute differences occurred between trials in frontalis EMG activity.     

Hypotonicity stimulates translocation of ICln in neonatal rat cardiac myocytes

 Cell volume expansion stimulates the efflux of solutes, including the amino acid taurine, to accomplish a regulatory volume decrease (RVD). One protein that may play a role in taurine efflux is the cytosolic protein ICln. In rat neonatal cardiac myocytes under isotonic conditions, ICln is found predominantly (greater than 90%) in the cytosol. However, after cell volume expansion by exposure to hypotonic medium, ICln rapidly translocates to the particulate fraction (the Triton X-114-insoluble fraction). After 2 min in hypotonic medium the percentage of ICln in the particulate fraction increases to 30%, 46% at 5 min, 40% at 10 min, and 25% at 30 min. The time course of this response is similar to that of hypotonicity-stimulated taurine efflux. Hypotonicity-stimulated taurine efflux as well as ICln translocation parallel the reduction in medium osmolarity. As osmolarity decreases, taurine efflux and ICln movement increase. The movement of ICln from the particulate back to the cytosolic fraction is accelerated when volume-expanded cells are returned to isotonic medium. When ICln is analyzed under non-denaturing conditions, a dimer is detected in the particulate fraction of volume-expanded cells, along with the monomer. This dimer is not detected in the cytosol. Treatment of the particulate fraction from volume-expanded cells with the lyotropic agent KSCN caused release of ICln but not Na-K-ATPase into the soluble fraction, indicating that translocated ICln associates with membranes in the particulate fraction rather than inserting into them. Received: 31 October 1997 / Received after revision and accepted: 23 March 1998     

In vitro studies on the mechanism of action of a new antiallergic,Ro 21-7634

The effects of Ro 21-7634 and disodium cromoglycate (cromoglycate) on the in vitro release of mediators of anaphylaxis from rat peritoneal cells and guinea pig lung tissue were compared. Ro 21-7634 was 25 fold more potent than cromoglycate as an inhibitor of antigen-induced histamine release from passively sensitized (IgE) rat peritoneal cells. Ro 21-7634 was also the more potent inhibitor of both compound 48/80- and concanavalin A-induced histamine release from rat peritoneal cells. The two drugs shared the common properties of producing the same maximal level of inhibition in each of the above releasing systems and exhibiting a time and concentration dependent loss of inhibitory activity when added to the cells prior to the releasing agent. Neither drug inhibited ionophore A23187- or ionophore X537A-induced histamine release from these cells. Ro 21-7634 inhibited antigen-induced (IgG₁) histamine and SRS-A release from actively sensitized guinea pig lung fragments, whereas cromoglycate did not. The results indicate that Ro 21-7634 and cromoglycate act through a common mechanism to inhibit allergic mediator release and that Ro 21-7634 is the more potent inhibitor.     

Diagnosis of Chlamydia trachomatis urethritis in men by polymerase chain reaction assay of first-catch urine.

To determine the accuracy of a recently developed polymerase chain reaction (PCR) urine assay to detect Chlamydia trachomatis urethral infection in men, we obtained urethral swabs and first-catch urine from 365 men attending a sexually transmitted diseases clinic. Thirty-three (9%) of the 365 men were infected with C. trachomatis as defined by urethral culture. Thirty-two of the 33 men with culture-positive urethral swabs also had PCR-positive urine assays. Of 332 patients with culture-negative urethral swabs, 325 had PCR-negative urine. Compared with chlamydia culture of urethral specimens, PCR assay of urine samples thus had a sensitivity of 97% and a specificity of 98%. The positive predictive value of the urine PCR assay was 82%, and the negative predictive value was 99%. Analysis of discrepant results indicated that six of seven PCR-positive, urethral culture-negative patients probably had chlamydial urethritis. All six patients had symptoms of urethritis and had either a positive urethral swab PCR or a positive urine PCR with a different amplification target. After resolution of discrepant results, (defining true positives as the 33 culture-positive patients and the 6 PCR-positive, culture-negative patients just described), the sensitivity and specificity of culture were 85% (33 of 39) and 100% (326 of 326), respectively. The revised sensitivity and specificity of PCR were 97% (38 of 39) and 99.7% (325 of 326), respectively. We conclude that this urine PCR assay provides a highly sensitive, noninvasive alternative method for the detection of C. trachomatis urethral infection in high-risk men attending a sexually transmitted diseases clinic. This assay could greatly facilitate the testing of larger numbers of male patients for chlamydial infection and should be studied in other settings.     

Hyper-reactivity to amphetamine in rats with dopaminergic grafts

Summary Rats with dopaminergic lesions were subsequently given grafts of dopaminergic (DA) neurons in various brain regions, and later tested for behavioral reactivity to amphetamine. Two experimental situations were used. 1) Amphetamine-induced circling behavior was measured in animals with unilateral lesion of the nigrostriatal pathway implanted with intrastriatal grafts, 2) locomotor activation by amphetamine was measured in animals with bilateral lesions and grafts in the nucleus accumbens. In both situations, behavioral overcompensation was observed after grafting. Ipsilateral circling, which is caracteristic of a unilateral lesion of the nigrostriatal pathway, gave way to contralateral circling, and locomotor activity was restored to levels above those observed for control animals. This behavioral overcompensation is a reflection of hyperreactivity of grafted animals to amphetamine: they were found to respond to much lower doses than controls and the effect of the drug lasted longer. This enhanced response does not seem to be due to post-synaptic hypersensitivity, but rather to hyper-reactivity of the grafted neurons themselves to amphetamine. The mechanism of this phenomenon, which seems to be a general property of grafted DA neurons is discussed.     

Receptor-binding properties of modern human influenza viruses primarily isolated in Vero and MDCK cells and chicken embryonated eggs

To study the receptor specificity of modern human influenza H1N1 and H3N2 viruses, the analogs of natural receptors, namely sialyloligosaccharides conjugated with high molecular weight (about 1500 kDa) polyacrylamide as biotinylated and label-free probes, have been used. Viruses isolated from clinical specimens were grown in African green monkey kidney (Vero) or Madin-Darby canine kidney (MDCK) cells and chicken embryonated eggs. All Vero-derived viruses had hemagglutinin (HA) sequences indistinguishable from original viruses present in clinical samples, but HAs of three of seven tested MDCK-derived isolates had one or two amino acid substitutions. Despite these host-dependent mutations and differences in the structure of HA molecules of individual strains, all studied Vero- and MDCK-isolated viruses bound to Neu5Ac alpha2-6Galbeta1-4GlcNAc (6'SLN) essentially stronger than to Neu5Acalpha2-6Galbeta1-4Glc (6'SL). Such receptor-binding specificity has been typical for earlier isolated H1N1 human influenza viruses, but there is a new property of H3N2 viruses that has been circulating in the human population during recent years. Propagation of human viruses in chicken embryonated eggs resulted in a selection of variants with amino acid substitutions near the HA receptor-binding site, namely Gln226Arg or Asp225Gly for H1N1 viruses and Leu194Ile and Arg220Ser for H3N2 viruses. These HA mutations disturb the observed strict 6'SLN specificity of recent human influenza viruses.     

Deletion of 20p 11.23----pter with normal growth hormone-releasing hormone genes

Using a molecular analysis of the DNA from a patient with a deletion of chromosome 20 [46,XX,del(20)(p 11.23)], we have excluded the growth hormone-releasing hormone (GHRH) gene from the region 20p11.23----pter. The patient had minor facial anomalies. Rieger eye anomaly, a congenital heart defect, severe failure to thrive, and a neurosecretory problem in growth hormone (GH) secretion. Since the GHRH gene was previously mapped to chromosome 20, we used molecular genetic methods to determine whether the growth abnormalities were due to the deletion of this gene. DNAs of the patient and 2 normal control subjects were analyzed by quantitative Southern blotting using a DNA probe for the GHRH gene and 2 reference DNA probes mapping to chromosome 21. The GHRH gene was found to be present in 2 copies in the patient. This indicates that the gene for GHRH maps to the region outside the patient's deletion, in 20p11.23----qter. Furthermore, our results suggest that genes other than GHRH on 20p are important for developmental steps leading to normal neurosecretory function of GH and may also be involved in generating Rieger eye anomaly. Finally, GH deficiency and Rieger eye anomaly should be sought in other patients with deletions of 20p.     

3q−, 3q+ anomaly in malignant proliferations in humans

Anomalies of both No. 3 chromosomes, of the t(3q?; 3q+) type can be observed in human malignancy as reported previously. It is our experience that this anomaly is found predominantly in myeloproliferative disorders, as a rather rare event, though occurring more frequently than similar exchanges between other homologous chromosomes. Previous claims about a relationship between this anomaly and thrombocytosis could not be confirmed, but the features found in a few patients indicate that further research should be undertaken to clarify this point.     

Immunohistochemistry of a spontaneous murine ovarian teratoma with neuroepithelial differentiation. Neuron-associated beta-tubulin as a marker for primitive neuroepithelium

Spontaneous ovarian teratomas develop in a large proportion of female LT strain mice. These tumors display a large neuroectodermal component with morphologic differentiation ranging from primitive neuroepithelium (medulloepithelial and ependymoblastic rosettes) to mature neurons, and provide a useful system for the study of various asynchronous stages of neuroepithelial differentiation. The aim of this study was to assess the expression of various cytoskeletal proteins in conjunction with other differentiation-related antigens in these tumors. We found that the medulloepithelial rosettes reacted with only two anti-beta-tubulin monoclonal antibodies. One of these (TU27) recognizes an epitope common to all of the mammalian beta-tubulin isotypes. The other monoclonal antibody (TUJ1) recognizes an epitope unique to class III beta-tubulin isotypes (neuronal-associated). Whereas immunoreactivity in the ependymoblastic rosettes was limited to TU27, differentiating polar neuroblasts reacted with both TU27 and TUJ1 and expressed neuron-specific enolase, synaptophysin, and the 68 kilodalton subunit of neurofilament protein. In well-differentiated foci, mature neurons were positive for all three neurofilament protein subunits (68, 168 and 200 kilodaltons), microtubule-associated-protein 2, synaptophysin, and neuron-specific-enolase, and reacted with both TU27 and TUJ1. By contrast, glial elements expressed glial fibrillary acidic and S-100 proteins, Leu-7 and TU27 but not TUJ1. Myelin basic protein and myelin-associated glycoprotein reactivity was found in the neuropile of these mature areas. The neuroepithelial components were negative for retinal S-antigen and cytokeratin. The expression of the class III beta-tubulin isotype by medulloepithelial rosettes suggests that this isotype may be one of the earliest markers to signal neuronal commitment in primitive neuroepithelium.