Novel microwave integrated lowpass filters

The procedure is described for synthesising Cauer Cheby?shev lowpass filters of the third order as rectangular microwave integrated structures. The synthesis procedure is based on a two-mode approximation and leads to structures with very small dimensions compared with the usual realisations of such type of filters. The experimental behaviour is shown to be quite satisfactory, particularly in the passband, where the filters show a better performance than the corresponding lowpass prototypes.     

Uncertainty orientation: Implications for affective and cognitive views of achievement behavior.

Three studies, with 734 undergraduates, tested the hypothesis that differences in performance due to achievement-related motives are moderated by individuals' uncertainty orientation—the degree to which situations of certainty vs uncertainty are cognitively relevant. The validity of this hypothesis was investigated for 3 predictions derived from J. W. Atkinson and J. O. Raynor's (1974) theory of achievement motivation: (a) Differences in performance due to achievement-related motives are greatest in situations of intermediate difficulty; (b) differences in performance due to achievement-related motives are greatest on tasks that must be successfully completed in order to move on to further tasks (contingent path tasks); and (c) differences in course grades due to achievement-related motives are greatest among those individuals who perceive the course as instrumental to their future goals. All 3 predictions were confirmed for uncertainty-oriented Ss, but results were actually reversed for certainty-oriented Ss. It is argued that the present formulation subsumes and integrates the existing cognitive and motivational interpretations of achievement behavior. (42 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Endogenous nitric oxide modulates morphine-induced changes in locomotion and food intake in mice

Opioids increase the dopaminergic turnover in nucleus striatum and nucleus accumbens of mice, causing behavioural changes such as increased locomotion and food intake. We have now shown that L-arginine administration increases morphine-induced locomotion and changes in food intake in mice. D-Arginine had no effect, suggesting a stereospecific mechanism. Furthermore NG-nitro-L-arginine methyl ester, a specific inhibitor of nitric oxide synthase, reduced the morphine-induced effects. These results suggest that endogenous nitric oxide could play a role in the modulation of dopaminergic effects elicited by morphine.     

Retroviral transfer of a bacterial alkyltransferase gene into murine bone marrow protects against chloroethylnitrosourea cytotoxicity

The chloroethylnitrosoureas (CENUs) are important antineoplastic drugs for which clinical utility has been restricted by the development of severe delayed myelosuppression in most patients. To investigate the potential of DNA repair proteins to reduce bone marrow sensitivity to the CENUs, we transferred the Escherichia coli ada gene, which encodes a Mr 39,000 O6-alkylguanine-DNA alkyltransferase (ATase), into murine bone marrow cells by the use of a high-titer ecotropic retrovirus. The ada-encoded ATase is resistant to O6-benzylguanine (O6-BG), a potent inhibitor of the mammalian ATases, thus affording the bone marrow an additional level of protection against CENUs. In methylcellulose cultures, ada-infected hematopoietic progenitor cells were twice as resistant as uninfected cells to the toxic effects of 1, 3-bis(2-chloroethyl)-1-nitrosourea (BCNU) following treatment with O6-BG. Although showing no obvious protective effects against leukopenia, overexpression of the bacterial ATase activity reduced the severity of anemia and thrombocytopenia in mice treated with O6-BG and BCNU. These effects, which were maximal at a BCNU dose of 12.5 mg/kg, were associated with improved survival when BCNU was given at this dose. At lower BCNU doses cytotoxicity was limited in both transduced and control mice, and at higher doses the protective effect was saturated due to cytotoxicity. These results suggest that ada gene therapy may be a feasible approach to amelioration of delayed myelosuppression following O6-BG plus CENU combination chemotherapy.     

HLA-DPB1 mismatch at position 69 is associated with high helper T lymphocyte precursor frequencies in unrelated bone marrow transplant pairs

HLA incompatibility between bone marrow recipient and unrelated donor pairs is often associated with severe acute graft-versus-host disease following bone marrow transplantation. Due to the extensive polymorphism of HLA genes, finding genotypically identical pairs is a difficult challenge. Therefore, it is crucial to single out the relevance of each HLA gene and, within each sequence, the polymorphic positions that induce a T-cell response. Among HLA class II genes, the relevance of HLA-DPB1 in inducing graft-versus-host disease is still controversial. In this study, we selected 37 bone marrow transplant pairs on the basis of HLA class I A and B identity as determined by isoelectric focusing and of class II identity as determined by serology and by low-resolution genomic typing. We analyzed them for the possible relationship between frequency of cytotoxic T lymphocyte and helper T lymphocyte precursors (CTLp and HTLp, respectively) and genomically determined class II mismatches. Seventeen pairs had high numbers of both CTLp and HTLp. They were not further considered because of the difficulty in determining whether the T-cell response was induced by class I or class II mismatches. Of the remaining pairs with low CTLp and high HTLp, six had disparities at HLA-DRB1 and HLA-DPB1 genes, and 14 differed only at the HLA-DPB1 locus. Among the latter pairs, we found a correlation between HLA-DPB1 mismatches and HTLp frequency, thus suggesting that disparity at this locus influences the alloreactive T-cell response. When the HTLp frequency was correlated with each single mismatch found in the 14 pairs, it appeared that the nature of the amino acid at position beta69 played a relevant role in inducing alloreactivity.     

Synthesis and pharmacological activity of deltorphin and dermorphin-related glycopeptides

The solid phase procedure, based on the Fmoc chemistry, was used to prepare some opioid deltorphin (H-Tyr-D-Ala-Phe-Asp-Val-Val-Gly-NH2, DEL C) and dermorphin (H-Tyr-D-Ala-Phe-Gly-Tyr-Pro-Ser-NH2, DER) analogues in which a D-glucopyranosyl moiety is beta-O-glycosidically linked to a Thr4 or Thr7 side chain. Their activities were determined in binding studies based on displacement of mu- and delta-receptor selective radiolabels from rat brain membrane synaptosomes, in guinea pig ileum and rabbit jejenum bioassays, and, in vivo, by a mouse tail-flick test after intracerebroventricular (icv) and subcutaneous (sc) administrations. The glyco analogues modified at position 4 displayed low opioid properties, while Thr7-glycosylated peptides retained high delta- or mu-selectivity and remarkable activity in vivo. In particular, as systemic antinociceptive agents, the latter glucoside-bearing compounds were more potent than the parent unglycosylated peptide counterparts, showing a high blood to brain rate of influx which may be due to the glucose transporter GLUT-1.     

Groupthink and uncertainty orientation: Personality differences in reactivity to the group situation.

Groupthink theory explains how situational conditions influence group decision making. The authors predict that certainty-oriented (CO) groups show more groupthink than do uncertainty-oriented (UO) groups under closed- rather than open-leadership conditions, this difference being greater under high- rather than low-cohesion conditions. Groupthink can be diminished by avoiding their leader's biased information. The authors asked 68 groups of 4 to decide the fate of a legal case. They found that CO groups are more influenced by situational conditions than are UO groups and that COs make fewer biased decisions with open- rather than closed-leadership conditions and discuss more facts and take more time under high rather than low cohesion. Cohesion interacts with personality to affect group processes but not the decision outcome. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Uncertainty orientation, the self, and others: Individual differences in values and social comparison.

97 undergraduates completed materials from which uncertainty orientation was assessed. Several months later, 60 of the Ss were asked to complete an abbreviated version of G. W. Allport and P. E. Vernon's (1931) values survey. Subsequently, they were shown their scores and permitted to view as many comparison scores as they wished. Uncertainty-oriented Ss (UCOSs) viewed more comparison scores than did certainty-oriented Ss (COSs). This occurred regardless of whether they believed that the scores came from a similar (student) or dissimilar (community) sample or of how important the specific value was to them. UCOSs also scored higher than COSs in theoretical and aesthetic values on the values survey, reflecting an interest in trying to understand one's world. COSs scored higher in religious values. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Solid papillary tumor of the pancreas. A clinical case

A method is presented for the investigation of surfactant function after isolation and preparation of pulmonary surfactant from tracheobronchial aspirates of mechanically ventilated infants and children. This method involved purification of surfactant from contaminating non-surfactant phospholipids and mucus by sodium bromide density gradient centrifugation. The surfactant concentration in undiluted fluids (3.5 +/- 0.8 mg mL-1; mean +/- SD) was calculated by extrapolating from the urea concentration in aspirates and serum. Phospholipid concentration was adjusted to approximately 3 mg mL-1 and the surface activity was determined by means of a pulsating bubble surfactometer. Mean minimal and maximal tension values of all cycles were calculated after reaching steady state. Measurements obtained from surfactant isolated with this method showed a high reproducibility: the coefficient of variation for minimal surface tension was 6.1%. Therefore this method enables functional surfactant analysis in tracheobronchial aspirates.