Participation of angiotensin II in learning and memory. III. Interactions of angiotensin II with GABAergic drugs

The experiments were carried out on male albino rats trained and tested for retention (24 hr later) in a shuttle-box. Angiotensin II (AT II) 0.10 micrograms intracerebroventricularly (i.c.v.), gamma-aminobutyric acid (GABA) 100 micrograms i.c.v., bicuculline 0.5 and 1.0 mg/kg intraperitoneally (i.p.), and picrotoxin 0.5 and 1.0 mg/kg i.p. administered independently or in combinations immediately after training. AT II was found to improve retention. GABA also facilitated retention. Combination of AT II + GABA potentiated the memory-improving effect of AT II. Bicuculline and picrotoxin at a dose of 0.5 mg/kg did not affect retention, while at a dose of 1.0 mg/kg they improved it. Combinations of AT II + bicuculline (0.5 mg/kg) and AT II + picrotoxin (0.5 mg/kg) abolished the retention-improving effect of AT II. Bicuculline (0.5 mg/kg) or picrotoxin (0.5 mg/kg) abolished the retention-facilitating effect of the combination of AT II + GABA as well as the potentiating action of GABA on the memory effect of AT II. These results suggest the participation of GABAergic transmission in the CNS in the mechanisms of the long-term memory-improving effect of AT II.     

Intraoperative radiotherapy (IORT) is an option for patients with localized breast recurrences after previous external-beam radiotherapy

Background  

For patients suffering of recurrent breast cancer within the irradiated breast, generally mastectomy is recommended. The normal tissue tolerance does not permit a second full-dose course of radiotherapy to the entire breast after a second breast-conserving surgery (BCS). A novel option is to treat these patients with partial breast irradiation (PBI). This approach is based on the hypothesis that re-irradiation of a limited volume will be effective and result in an acceptable frequency of side effects. The following report presents a single center experience with intraoperative radiotherapy (IORT) during excision of recurrent breast cancer in the previously irradiated breast.     

Changes in the Eeg Background Activity of Children with Acute Lymphoblastic Leukemia During Cytotoxic Therapy

Thirteen children with acute lymphoblastic leukemia (ALL) were investigated before and during cytotoxic therapy. EEG findings were correlated with the clinical course and the therapy protocol and compared with normal data obtained from 295 healthy children. Frequency analysis of the background activity of the EEG revealed an initial slowing of the background activity prior to therapy and further slowing each time a combination of vincristine (VCR), daunorubicine (DAU) or adriblastine (ADR), prednisone (FRED), and L-asparaginase (L-ASP) was administered. The slowing of the background activity correlated only with the administration of these drugs. DAU, ADR, and FRED are not known to influence the EEG; therefore, VCR and L-ASP remain the primary candidates responsible for the central nervous system alteration.     

Effects of the angiotensin II type 1 receptor antagonist telmisartan on monocyte adhesion and activation in patients with essential hypertension.

Circulating monocytes from hypertensive patients show elevated secretion patterns of pro-inflammatory cytokines, an increased expression of adhesion molecules, and an increased adhesion to vascular endothelial cells. We tested the hypothesis that telmisartan, an angiotensin II type 1 (AT(1)) receptor antagonist, reduces the activation of circulating monocytes from hypertensive patients and diminishes the monocyte-endothelial cell adhesion. Monocytes of 20 hypertensive patients and 20 normotensive controls were isolated by density gradient centrifugation and Dynabeads, and the monocyte adhesion to human aortic endothelial cell monolayers was measured by adhesion assays. To characterize monocyte activation we assessed the expression of activity-related cell surface markers that are also involved in monocyte adhesion to endothelial cells, such as CD11a/b and CD54, as well as the chemokine receptors CCR1, CCR2 and CCR5 before and after telmisartan therapy using flow cytometry. Spontaneous adhesion of monocytes from hypertensive patients and the adhesion after stimulation with angiotensin II were significantly increased compared with those in normotensive controls (p<0.05). Treatment of hypertensive patients with the AT(1) receptor antagonist telmisartan significantly diminished the adhesion of circulating monocytes to human endothelial cells (p=0.02) despite the increase in the expressions of CD11b, CD54 and CCR5 after telmisartan therapy. Reducing monocyte adhesion may be a novel beneficial effect of the AT(1) receptor antagonist telmisartan helping to prevent vascular alterations in hypertension. The mechanism of action remains to be elucidated, since reduction in monocyte adhesion was not attributable to changes in adhesion molecule expression.     

Chromosome localizations of genes for five cAMP-specific phosphodiesterases in man and mouse

Cyclic nucleotides are important second messengers that mediate a number of cellular responses to external signals. Cyclic nucleotide phosphodiesterases play a role in signal transduction by regulating the cellular concentrations of these messengers. Here, we have applied Southern analyses of somatic cell hybrid lines and of recombinant inbred (RI) mouse strains as well as fluorescence chromosomal in situ hybridization (FISH) to chromosomally localize five cAMP-specific nucleotide phosphodiesterase genes in human and mouse. GenesDPDE1, DPDE2, DPDE3, andDPDE4 that share sequence homology with theDrosophila dunce gene were assigned to human chromosomes 19 (DPDE1 andDPDE2), 5q12 (DPDE3), and 1p31 (DPDE4) and to mouse chromosomes 8, 9, 13, and 4, respectively. The high-affinity cAMP-specific phosphodiesterase gene (HCP1) was mapped to human chromosome 8q13-q22. Since these genes are potential candidates for involvement in psychiatric or behavioral disorders, knowledge of their chromosomal localizations will facilitate the discovery of their association with disease genes as they are being mapped by linkage studies.