Population and pharmacogenetic studies on serum cholinesterase (E): estimates of theE 1 andE 2 allele frequencies for the population of Central Italy,and of the correlation between E activity and sensitivity to succinylcholine (SCC)

392 random patients treated with SCC prior to surgery were assayed for pseudocholinesterase activity and electrophoretic pattern. The estimate of the percent frequencies of theE ₁ ^a allele were 1.16±0.38 and of the C₅ (+) phenotype 9.7±1.5, both typical of Caucasian populations. By combining the presentE ₁ ^a gene frequency estimate with that from another sample of the same population (Cermele et al., 1987) a better estimate with smaller confidence limits was obtained, that is: 1,14±0,27. One subject interpreted asE ₁ ^a E ₁ ^a on phenotypic grounds was also found (expected 0,05) in this random sample. A correlation coefficient of −0.521 was found between E activity and myorelaxation time in the whole sample. High correlation values (r=−0.55 and r=−0.46) were found forE ₁ ^u E ₁ ^u ; C₅ (−) andE ₁ ^u E ₁ ^u ; C₅ (+) individuals, respectively, showing a strong dependence of the latter variable on the former one even within apparently homogeneous classes. The use of the product of these two variables as a classification criterion allowed the identification of a subject with very long myorelaxation time but normal activity.     

Effect of the growth conditions on the expression of cell-surface-associated platelet-derived growth factor receptors in mouse fibroblasts

The conditions affecting the appearance and disappearance of platelet-derived growth factor (PDGF) receptors from the pool of active cell surface-associated receptors were studied. Receptor molecules were revealed in intact Swiss 3T3 fibroblasts by their ability to bind 125I-labeled PDGF and, due to their property to become phosphorylated in tyrosine following ligand binding, by antibodies to phosphotyrosine. PDGF receptor molecules were found to be quite scarce in exponentially growing fibroblasts as compared to quiescent cells. When growing cells were either shifted to a medium containing plasma or received suramin in the culture medium, cell surface-associated PDGF receptors largely increased. This process required about 12 h. Incubation of quiescent cells in serum, but not in plasma, induced a slow decrement of ligand-activatable receptors. In the presence of PDGF the rate of receptor removal from the cell surface was very rapid and was a function of the PDGF concentration. Quiescent cells deprived of cell-surface receptors by incubation with PDGF reexpressed PDGF receptors in about 14 h.     

Adenylosuccinate synthetase: site of action of hydantocidin, a microbial phytotoxin.

The site of action of hydantocidin was probed using Arabidopsis thaliana plants growing on agar plates. Herbicidal effects were reversed when the agar medium was supplemented with AMP, but not IMP or GMP, suggesting that hydantocidin blocked the two-step conversion of IMP to AMP in the de novo purine biosynthesis pathway. Hydantocidin itself did not inhibit adenylosuccinate synthetase or adenylosuccinate lyase isolated from Zea mays. However, a phosphorylated derivative of hydantocidin, N-acetyl-5'-phosphohydantocidin, was a potent inhibitor of the synthetase but not of the lyase. These results identify the site of action of hydantocidin and establish adenylosuccinate synthetase as an herbicide target of commercial potential.     

HIV protease inhibitors are potent anti-angiogenic molecules and promote regression of Kaposi sarcoma

Treatment with HIV-1 protease inhibitors (PI) is associated with a reduced incidence or regression of Kaposi sarcoma (KS). Here we show that systemic administration of the PIs indinavir or saquinavir to nude mice blocks the development and induces regression of angioproliferative KS-like lesions promoted by primary human KS cells, basic fibroblast growth factor (bFGF), or bFGF and vascular endothelial growth factor (VEGF) combined. These PIs also block bFGF or VEGF-induced angiogenesis in the chorioallantoic membrane assay with a potency similar to paclitaxel (Taxol). These effects are mediated by the inhibition of endothelial- and KS-cell invasion and of matrix metalloproteinase-2 proteolytic activation by PIs at concentrations present in plasma of treated individuals. As PIs also inhibit the in vivo growth and invasion of an angiogenic tumor-cell line, these data indicate that PIs are potent anti-angiogenic and anti-tumor molecules that might be used in treating non-HIV KS and in other HIV-associated tumors.     

Brain oxytocin inhibits the (re)activity of the hypothalamo-pituitary-adrenal axis in male rats: involvement of hypothalamic and limbic brain regions

In response to various stressors, oxytocin is released not only into blood, but also within hypothalamic and extrahypothalamic limbic brain regions. Here, we describe the involvement of intracerebrally released oxytocin in the regulation of the activity of the hypothalamo-pituitary-adrenal (HPA) axis by infusion of the oxytocin receptor antagonist (des Gly-NH(2) d(CH(2))(5) [Tyr(Me)(2), Thr(4)] OVT; pH 7.4; Dr. M. Manning, Toledo, OH, USA) either into the lateral cerebral ventricle (icv[0.75 microg/5 microl,]) or via retrodialysis (10 microg/ml, 3.3 microl/min, 15 min) into the hypothalamic paraventricular nuclei (PVN), the medio-lateral septum or the amygdala. Male Wistar rats fitted with a chronic jugular vein catheter and an icv guide cannula or a microdialysis probe targeting the respective brain region 4 days prior to the experiment were blood sampled under basal as well as stressful conditions. Rats were exposed to the elevated platform (emotional stressor) and/or to forced swimming (combined physical and emotional stressor). Blockade of the receptor-mediated action of endogenous oxytocin within the PVN resulted in an enhanced basal secretion of ACTH whereas, in response to forced swimming, ACTH secretion was rather reduced, indicating a tonic inhibitory effect of OXT on basal HPA axis activity, but a potentiating action under conditions of stress. Within the medio-lateral septum, antagonist treatment did not alter basal ACTH secretion, but significantly disinhibited ACTH secretion in response to the elevated platform, but not to forced swimming. Within the amygdala, no significant effects either on basal or stress-induced HPA axis activity could be found. The results indicate a differential involvement of brain oxytocin in the regulation of the HPA axis activity which depends both on the site of intracerebral oxytocin release and the stressor the animals are exposed to.     

Prenatal diagnosis of a de novo satellited chromosome 18 (18ps) associated with 18p deletion

De novo satellited non-acrocentric chromosomes are very rare findings in prenatal diagnosis. Here we report the first case of a de novo 18ps, associated with del(18p), detected at prenatal diagnosis. A 37 years old woman underwent Chorionic Villus Sampling (CVS) for advanced maternal age. Cytogenetic analysis on direct CVS preparation (CVSc) revealed a male karyotype with a nonfamilial satellited 18ps and a reciprocal translocation t(17;19)(P11.1;q11) of maternal origin. The mesenchimal CVS culture (CVSm) showed a mosaic of cell lines with various involvement of chromosome 18: 18ps [36/70]/ r(18) [25/70]/ del(18p) [3/70]/ -18 [6/70]. Amniotic fluid cells (AFC) confirmed the homogeneous karyotype found at CVSc. The molecular cytogenetic characterization, performed on AFC, allowed the following diagnosis: 46,XY, +15, dic(15;18)(p11.1;p11.2), t(17;19)(p11.1;q11)mat. ish dic(15;18)(tel 18p-, D15Z1+, wcp18-, wcp 18+, D18Z1+, tel 18q+). The foetal autopsy disclosed subtle facial dysmorphisms and corpus callosum hypoplasia. In case of prenatal detection of de novo terminal ectopic NORs an accurate cytogenetic and molecular analysis should be performed in order to rule out subtle unbalancements.     

<Emphasis Type="Italic">Burkholderia</Emphasis> Hep_Hag autotransporter (BuHA) proteins elicit a strong antibody response during experimental glanders but not human melioidosis

Background  

The bacterial biothreat agents Burkholderia mallei and Burkholderia pseudomallei are the cause of glanders and melioidosis, respectively. Genomic and epidemiological studies have shown that B. mallei is a recently emerged, host restricted clone of B. pseudomallei.