Magnetic stimulation of the brain in generalized epilepsy: reversal of cortical hyperexcitability by anticonvulsants

Observations on experimental models suggest that diffuse cortical hyperexcitability is an important abnormality in the generalized epilepsies. We used the threshold for transcranial magnetic stimulation as an index of motor cortical excitability in 89 neurologically normal control subjects and 56 patients with idiopathic generalized epilepsy (20 untreated and 36 chronically treated with anticonvulsants). Magnetic stimulation was repeated in 10 patients after valproate monotherapy had been commenced and in 23 control subjects. The threshold intensity was significantly lower in the untreated patients (46 +/- 5% [mean +/- 95% confidence interval]) than in the control subjects (56 +/- 2%). Treated patients had significantly higher thresholds (64 +/- 4%) than did untreated patients and control subjects. A significant increase in threshold intensity (8 +/- 2%) occurred in patients retested after starting valproate; there was no significant change in retested control subjects (-1 +/- 2%). Threshold intensity was positively correlated with plasma valproate levels (rs = 0.37). The findings suggest that cortical excitability is increased in idiopathic generalized epilepsy and is reduced following anticonvulsant treatment. Transcranial magnetic stimulation is of use in examining the pathophysiology of generalized epilepsy. Furthermore, changes in threshold intensity in response to anticonvulsant treatment may prove useful in guiding therapy.     

Effect of timing of growth hormone administration on plasma growth-hormone-binding activity, insulin-like growth factor-I and growth in children with a subnormal spontaneous secretion of growth hormone

Since normal pulsatile growth-hormone (GH) secretion displays a major and consistent surge during sleep, we studied the effect of timing of GH supplementation on plasma GH-binding protein activity (GH-BP), insulin-like growth factor-I (IGF-I) and growth. 34 prepubertal subjects (28 boys, 6 girls) aged 8-11 years, of short stature (< 2 SD for age), with a GH response to provocative test > 10 micrograms/l and a subnormal 24-hour GH secretion (< 3 micrograms/l), were randomly allocated to receive Bio-Tropin (recombinant GH, Bio-Technology, Israel) 0.81 IU/kg/week in 3 equally divided doses. GH was administered either at 8.00-10.00 h (M group), 14.00-16.00 h (AN group) or 19.00-21.00 h (NT group). Height velocity, IGF-I and GH-BP were determined prior to and after 6 and 12 months on GH therapy in the three groups. There was no significant difference between the three groups in the growth response, IGF-I and GH-BP increase, all of which increased significantly during GH therapy. Although GH levels after the injection decline to preinjection levels after 10 h, the changes induced by GH therapy, as reflected in IGF-I and GH-BP, last in the circulation long enough to prevent fluctuations in its action. The similarity of IGF-I and of GH-BP levels in the three treatment groups might explain the similar growth effects of the 3 protocols.     

Some Remarks on Vortex Matter in High-T c Superconductors

We show that some experimentally observed features of vortex matter in high-T _c superconductors may be interpreted in simpler ways than it is usually done. In particular, we consider magnetic flux creep at low temperatures as well as the irreversibility line in the H–T phase diagram. We also discuss a new approach to the analysis of the equilibrium magnetization in the mixed state of type-II superconductors and we suggest an alternative configuration for the mixed state in magnetic fields close to the upper critical field.     

Molecular characterization of a Campylobacter jejuni lipoprotein with homology to periplasmic siderophore-binding proteins

A genomic library of Campylobacter jejuni (NCTC 11351) was used to identify genes which could confer a hemolytic phenotype to Escherichia coli. Accordingly, when transformants were screened on blood plates, hemolytic colonies appeared at a frequency of 3 x 10(-4). The gene conferring the hemolytic activity was identified by subcloning and was found to be responsible for the phenotype of all hemolytic transformants isolated. The open reading frame conferring this activity encodes a protein of 36,244 Da with a typical endopeptidase type II leader sequence. The protein is modified with palmitic acid when it is processed in E. coli, confirming that it is a typical lipoprotein. The deduced gene product of 329 amino acids has significant homology to the group of solute binding proteins from periplasmic-binding-protein-dependent transport systems for ferric siderophores, including the FatB protein from Vibrio anguillarium and the FhuD protein from Bacillus subtilis. In particular, the protein contained the signature sequence for siderophore-binding proteins, suggesting that the protein may be the siderophore-binding protein component of an iron acquisition system of C. jejuni.     

Expectancies for driving under the influence of alcohol among Hispanics and non-Hispanic Whites

A random sample of 1418 (40.8% male) Hispanics and 501 (46.1% male) non-Hispanic Whites were surveyed about their behavioral expectations for driving under the influence of alcoholic beverages (DUI). Hispanics reported more often than Whites that the effects of DUI would be driving carelessly, being angry at other drivers, feeling nervous, losing the respect of friends, feeling guilty, feeling too tired to drive, and losing their self-respect. There were gender differences among Hispanics but not among Whites. Hispanic abstainers reported the likelihood of the various outcomes more frequently than drinkers although drinking status produced no statistically significant differences among non-Hispanic Whites.     

Feeding behaviour and predation of a bat by Saimiri sciureus in a semi-natural Amazonian environment

A free-ranging group of Saimiri sciureus was studied in a semi-natural forest habitat in eastern Amazonia, where behaviour patterns were broadly similar to those recorded for the species in the wild. According to focal-animal samples, the monkeys spent the vast majority of their time foraging and feeding, in particular for arthropod prey, which contributed almost half of identified food items. The predation of a small-bodied bat was also observed, although the study animals did not appear to forage systematically for chiropterans in the manner recorded for Saimiri oerstedi.     

A cell surface receptor defined by a mAb mediates a unique type of cell death similar to oncosis

Cell death is mediated by distinct pathways including apoptosis and oncosis in response to various death signals. To characterize molecules involved in cell death, a panel of mAbs was raised by immunizing mice with apoptotic cells. One of these antibodies, designated anti-Porimin (for pro-oncosis receptor inducing membrane injury), was found to directly induce a unique type of cell death in Jurkat cells. Anti-Porimin defines a 110-kDa cell surface receptor on Jurkat cells. Functionally, anti-Porimin alone rapidly mediates pore formation on the plasma membrane and induces cell death without participation of complement. Both the cellular expression and functional characteristics of the Porimin antigen indicate that it is distinct from the CD95 (Fas/Apo-1) and other cell receptors known to induce apoptosis. Anti-Porimin-mediated cell death was preceded by cell aggregation, formation of plasma membrane pores, and the appearance of membrane blebs. More important, these cells show neither DNA fragmentation nor apoptotic bodies, but display lethal damage of the cell membrane. Cell death by anti-Porimin is distinct from complement-dependent cytolysis or complement-independent apoptosis but is similar to that described for oncosis, a form of cell death accompanied by the membrane damage followed by karyolysis. The induction of cell death by anti-Porimin may represent a unique cell surface receptor-mediated pathway of cell death in the human lymphoid system.     

Comparison of two different delay procedures in a rat skin flap model

The overall objective of this study was to investigate how a strategic delay procedure could generate large flaps survival. On the basis of the vascular anatomy in 10 rats, a long three-territory skin flap spanning the length of the rat dorsum was designed. This flap was distally based on the deep circumflex iliac artery. The adjacent territories consisted of a large perforator of the posterior intercostal artery and the lateral thoracic artery in sequence. Two different vascular delay procedures were used and compared in nine animals. One dorsal midline incision was used to perform the two different delay procedures. The limited delay technique was performed by ligating a large cutaneous perforator of the posterior intercostal artery on one side of the rat. The extensive delay procedure was completed by ligating the cutaneous perforators of the posterior intercostal artery and the lateral thoracic artery on the other side of the rat. After a delay period of 10 days, the paired flaps were elevated, respectively, and sutured back in place. Seven days later, the area of viable skin flap was measured by the paper template technique. The animals were then killed, and the dorsal skin arteriograms were obtained by injecting a lead oxide mixture. Vascular changes of the paired flaps were assessed. In the extensive delay group, 100-percent survival was seen in four animals and distal partial necrosis was observed in five animals. The average survival area in the extensive delay group was 85.5 +/- 14.2 percent (mean +/- SD), whereas the flaps in limited delay group showed 100-percent survival in all animals (p < 0.05). In flaps that survived completely, the choke vessels among three vascular territories anastomosed throughout the flap. In the partially necrotic flaps, some choke and true anastomoses existed between the deep circumflex iliac and the posterior intercostal artery territories and the flap necrosis occurred in the third territory. This study suggests that the limited delay technique (ligation of one artery in the territory adjacent to the base of the flap) was the more effective delay procedure in the rat dorsal skin flap model.