Biofeedback control of migraine headaches: A comparison of two approaches

In order to assess the relative effectiveness of finger warming and temporal blood volume pulse reduction biofeedback in the treatment of migraine, 22 female migraine patients were assigned to one of three experimental conditions: temporal artery constriction feedback, finger temperature feedback, or waiting list. Biofeedback training consisted of 12 sessions over a 6-week period. All patients completed 5 weeks of daily self-monitoring of headache activity (frequency, duration, and intensity) and medication before and after treatment. Treatment credibility was assessed at the end of Sessions 1, 6, and 12. Results showed that temporal constriction and finger temperature biofeedback were equally effective in controlling migraine headaches and produced greater benefits than the waiting list condition. Power analyses indicated that very large sample sizes would have been required to detect any significant differences between the two treatment groups. No significant relationships were found between levels of therapeutic gains and levels of thermal or blood volume pulse self-regulation skills. Likewise, treatment outcome was not found to be related to treatment credibility. Further analyses revealed that changes in headache activity and medication were associated with changes in vasomotor variability. Because blood volume pulse variability was not significantly affected by biofeedback training, questions about its role in the therapeutic mechanism are raised.This research was supported in part by grants from the Quebec Ministry of Education and the Quebec Ministery of Social Affairs to the first author, and an award from the Medical Research Council of Canada to the second author. The authors are indebted to Drs. Frank Andrasik, Howard Barbaree, Edward Blanchard, Martin Ford, and Patrick McGrath, as well as to two anonymous reviewers, for their helpful comments on an earlier draft of this paper.     

Segmental pulmonary vascular resistance in progressive hydrostatic and permeability edema

We used the in situ blood-perfused left lower lobe preparation of the dog to examine the effect of hydrostatic and permeability edema on the slope and intercept of the vascular pressure-flow (P/Q) relationship and on the longitudinal distribution of vascular resistance with the arterial and venous occlusion technique. Hydrostatic edema (HE) was induced by raising the venous pressure, and permeability edema (PE) was induced with alpha-naphthylthiourea. When the hematocrit (Hct) of the perfusate was kept normal (approximately 40%), HE had no significant effect on either the slope or the intercept of the P/Q relationship or on the distribution of vascular resistance. PE caused a small increase in the intercept of the P/Q relationship and a small rise in the resistance of the vessels in the middle segment. In another series of HE experiments in which Hct was allowed to increase during edema formation, there was a marked increase in vascular resistance. We conclude that edema per se does not increase vascular resistance significantly and that the increases in vascular resistance which were observed previously by other investigators in the isolated lungs may be due to increases in blood hematocrit.     

Absence of genotoxic effects of nonasbestos mineral fibers

The biological activity of natural and synthetic mineral fibers has been examined. Natural attapulgite [(Mg, Al)₂Si₄O₁₀(OH).4H₂0], synthetic xonotlite [Ca₃Si₃O₈(OH)₂] and natural sepiolite [Mg₂Si₃O₈.2H₂O] were selected. Genotoxic effects were investigated by means of a well established cellular model based upon the measurement of unscheduled DNA synthesis (UDS) in rat hepatocytes in primary culture. The intrinsic capacity of the fibers (1 and 10 µ/ml) to induce UDS was first tested. None of the fiber types showed detectable UDS-eliciting activity. Also, the possible modulation of the cellular response to genotoxic agents by the materials was examined by exposing the cells to mixtures of 2-acetylaminofluorene (AAF) (0.05 and 0.25 µg/ml) and fibers (1 and 10 µg/ml). In these experiments, the UDS response was significantly diminished in the presence of xonotlite. This phenomenon may reflect changes in the uptake and/or metabolism of AAF or may result from an inhibition of DNA repair processes, the latter suggesting a possible cocarcinogenic potential for this synthetic silicate. These results point to the immediate necessity of studying more extensively the biological effects of fibrous materials that can be used as substitutes for asbestos.Abbreviations AAF 2-acetylaminofluorene - DMSO dimethyl-sulfoxide - FBS fetal bovine serum - IRDA Institut de Recherche et de Développement sur l'Amiante - LDH lactate dehydrogenase - UDS unscheduled - DNA synthesis - WME Williams' Medium E This work was supported by the Institut de Recherche et de Développement sur l'Amiante (IRDA), Sherbrooke, Canada.     

Annual activity and life cycles of carabid beetles in two forest communities

The annual activity and life cycles of thirteen species of carabid beetles coexisting in two forests in Belgium were studied by recording above-ground activity of adult and larval populations, and by examining the reproductive condition of adults in the course of the year. The cycles were far more complex and diversified than suggested by previous works. Besides typical "spring breeders" and "autumn breeders", species were found

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  with a continuous reproductive period from spring to autumn,
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  with several variable breeding periods, part of the population overwintering as adults, part as larvae,
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  with a breeding period that begins facultatively in autumn and continues the next spring,
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  with a winter reproduction.

Comparison of life cycles in Scandinavia and In Belgium also shows their variability in relation to climate. More flexible and varied cycles are made possible by the milder winters further south. Existing classifications of life cycles of carabids appear unable to account for such a diversity and variability.     

Microlocating lithium in the mouse embryo by use of a (n, α) nuclear reaction

Summary The quantitative imaging of lithium distribution, in histological sections of 15-days old mouse embryos (whose mother had been submitted to Li-treatment), was performed using⁶Li isotope as tracer,⁶Li(n,)³H nuclear reaction for detection, and dielectric track detectors. Despite the particular difficulties of cryosectioning the embryos without disturbing the lithium distribution, the Li regionalization appeared to be very clear-cut. The ectomesodermic tissues were significantly more loaded with lithium than the endodermic ones. This is probably related to the ectomesodermic tissues being also those most sensitive to the teratogenic effect of lithium. The Li-distribution in the embryo brain was almost homogeneous, instead of being heterogeneous as in adult brain. The mean Li-concentration in the embryo brain was not much below the Li concentration in the grey matter of the mother brain, but it was significantly larger than that in the white matter of the mother brain. Our results are discussed in the context of teratogenic effects observed in situ during mammalian development.     

Bufonid nucleocytoplasmic hybrids arrested at the early gastrula stage lack a fibronectin-containing fibrillar extracellular matrix

Summary Most hybrids betweenBufo bufo andB. calamita obtained by nuclear transplantation become arrested at the early gastrula stage. In both parental controls and the hybrid embryos, the presence and distribution of extracellular matrix was analysed with fluorescent wheat germ agglutinin and by immunolabelling with antibodies directed against fibronectin. InB. bufo andB. calamita gastrulae and in the few hybrids that complete gastrulation, the inner surface of the blastocoel roof is covered by a fibronectin-rich fibrillar matrix. In nucleocytoplasmic hybrids whose development was arrested at the gastrula stage, the fibronectin-containing extracellular matrix was either totally absent or poorly developed and disorganized.     

Time course localization of immunoglobulin M monoclonal antibody and its fragments in leukemic tumor-bearing mice

Summary In vivo localization of a mouse monoclonal antibody (F₂-10.23 IgM) binding leukemic L 1210 cells was studied in DBA/2 mice bearing an L 1210 tumor. F(ab)₂ fragments were prepared and their specific binding to L 1210 cells was analyzed by flow cytofluorometry. Radiolocalization studies were performed by using ¹²⁵I- or ¹³¹I-labeled IgM monoclonal antibody or its F(ab')₂ fragments to ascertain their capacity to visualize the L 1210 tumor. F(ab)₂ fragments were cleared more rapidly than the whole IgM; the clearance was as fast in healthy as in tumor-bearing mice. The tumor-to-muscle ratio observed 24 h after injection of ¹²⁵I-radiolabeled F(ab)₂ fragments and ¹²⁵I-radiolabeled IgM was 10; the radioactivity level in the blood with F(ab)₂ fragments was lower than with IgM, and so -camera imaging was workable with F(ab)₂ fragments without background substraction. The tumor localization was studied over a period of 5 days by recording the distribution of the iodinated fragments in the tumor-bearing leg compared with that in the normal leg, and by computer analysis of the region of interest. F(ab)₂ fragments gave better results than intact IgM in tumor visualization. Nevertheless, the rapid clearance of this antibody or its F(ab)₂ fragments make them hardly suitable as carriers of toxic drugs. Abbreviations used are: MEM Minimum essential medium; SDS sodium dodecylsulfate; PAGE polyacrylamide gel electrophoresis