A sensitive and rapid luminescence sandwich assay for antibodies to hepatitis-B surface antigen (Anti-HBsAg)

A chemiluminescent assay for hepatitis-B surface antigen is described which used an isoluminol derivative as the label. The assay is precise intra-assay CV, 1.96-2.45%; inter-assay CV, 5.26-8.11% and has a lower detection limit for hepatitis-B surface antigen of 1.3U/I.     

Genomic complexity and plasticity of Burkholderia cepacia

Abstract Burkholderia cepacia has attracted attention because of its extraordinary degradative abilities and its potential as a pathogen for plants and for humans. This bacterium was formerly considered to belong to the genus Pseudomonas in the γ-subclass of the Proteobacteria , but recently has been assigned to the β-subclass based on rrn gene sequence analyses and other key phenotypic characteristics. The B. cepacia genome is comprised of multiple chromosomes and is rich in insertion sequences. These two features may have played a key role in the evolution of novel degradative functions and the unusual adaptability of this bacterium.     

Switch and Bait: Probing the Discriminative Basis of Odor Identification via Recognition Memory

When people misidentify everyday odors, as they often do, theirerrors may conceivably lie in faulty perceptions or in faultyaccess to the names. Discussions of the matter usually focuson the latter, as if people had no problems with perceptualaccuracy. (The problem of faulty access may get attention becauseits high subjective impact makes it particularly memorable,when it does occur.) However, studies have demonstrated breakdownsin ability to discriminate quality, from which it follows thatpeople will misidentify items through perceptual confusions.Furthermore, misidentifications often contain considerable informationabout the identities of items, as if people simply did not perceivethe items accurately, but perhaps fuzzily or with some perceptualbias. Recognition memory, with a 2-day interval between inspectionand test, provided a vehicle to address two questions on thistopic: (i) Would people notice that we had switched items andhad presented for recognition items that matched their misidentificationsrather than the original items inspected? (ii) Would peoplenot only fall for the false bait, but actually identify theswitched items correctly, and thereby imply that they were ‘tuned’to perceive those odors? People commonly failed to notice theswitches, i.e. took the bait and commonly identified the switcheditems with veridical names. Although subject to further study,the outcome suggests that when people give such names as garlicfor vinegar, orange for lime, soy sauce for molasses and manyothers, the errors often lie largely at a perceptual stage ofprocessing, i.e. at input rather than output. Chem. Senses 21:35–44, 1996.     

Suffering, justice, and the politics of becoming

To suffer is to undergo, to bear, to endure. Suffering exists on the underside of agency; it is as important to ethics as agency. The experience of suffering is never entirely captured by the ethical, political, medical and spiritual categories in which it is represented. Perhaps an engagement with suffering can open up hidden connections between these domains. After examining John Caputo and Friedrich Nietzsche comparatively on the relation between suffering and ethics, this essay explores the relation of the politics of becoming to suffering. The politics of becoming is a paradoxical process by which a new cultural identity is drawn into being and yet is irreducible to the energies and motives that spurred its initiators to action. To exemplify and think the politics of becoming is to call into question the sufficiency of existing paradigms of morality. A critical examination of the Rawlsian model of justice brings out, for example, the insufficiency of justice to the politics of becoming. It suggests the need, first, to pursue an ethics of engagement between several parties drawing upon a variety of sources of ethical inspiration and, second, to cultivate ldcritical responsiveness to new social movements that struggle to place new identities onto the cultural register. If the latter movements sometimes modify general understandings of suffering, identity, justice and medical practice they also indicate the role cultural thinkers can play in re-examining periodically established codes of interaction between these domains.A paper presented, with commentaries, as the 1995 Roger Allan Moore Lecture at Harvard Medical School, Center for the Study of Culture and Medicine, May 11, 1995.     

Fate of the anterior neural ridge and the morphogenesis of the xenopus forebrain

The fate of the anterior neural ridge was studied by following the relative movements of simultaneous spot applications of DiI and DiO from stage 15 through stage 45. These dye movements were mapped onto the neuroepithelium of the developing brain whose shape was gleaned from whole-mount in situs to neural cell adhesion molecule and dissections of the developing nervous system. The result is a model of the cell movements that drive the morphogenesis of the forebrain. The midanterior ridge moves inside and drops down along the most anterior wall of the neural tube. It then pushes forward a bit, rotates ventrally during forebrain flexing, and gives rise to the chiasmatic ridge and anterior hypothalamus. The midanterior plate drops, forming the floor of the forebrain ventricle, and, keeping its place behind the ridge, it gives rise to the posterior hypothalamus or infundibulum. The midlateral anterior ridge slides into the lateral anterior wall of the neural tube and stretches laterally into the optic stalk and retina, and then rotates into a ventral position. The lateral anterior ridge converges to the most anterior part of the dorsal midline during neural tube closure, then rotates anteriorly, and gives rise to telencephalic structures. Whole-mount bromodeoxyuridine labeling at these stages showed that cell division is widespread and relatively uniform throughout the brain during the late neurula and early tailbud stages, but that during late tailbud stages cell division becomes restricted to specific proliferative zones. We conclude that the early morphogenesis of the brain is carried out largely by choreographed cell movements and that later morphogenesis depends on spatially restricted patterns of cell division. © 1995 John Wiley & Sons, Inc.     

Subject: Endocrinology and chronobiology

Research Notes on Avian Biology 1994: Selected Contributions from the 21st International Ornithological CongressMorphology and Physiology: Endocrinology

Subject: Endocrinology and chronobiology     

Regional Specificity in Alterations of Rat Brain Copper and Catecholamines Following Perinatal Copper Deficiency

Abstract: Perinatal copper deficiency was studied in 1-month-old female and male Sprague-Dawley rat offspring to investigate regional changes in brain copper and catecholamine levels. Offspring of dams given the low copper treatment beginning at day 7 of gestation exhibited signs characteristic of deficiency such as impaired growth and 10-fold lower liver copper levels compared with copper-adequate controls. Regional analysis of brain copper by graphite furnace atomic absorption spectroscopy revealed uniform and severe reduction of copper to levels 20 ± 3% of controls in all regions, except the hypothalamus, where reductions to 56 and 28% of those in copper-adequate females and males, respectively, were measured. HPLC analysis revealed significant reductions in norepinephrine levels in cerebrum, midbrain, corpus striatum, cerebellum, and medulla-pons of copper-deficient offspring ranging between 39 and 67% of control values. There were no significant differences in norepinephrine concentration in the hypothalamus. There was a significant, one-third reduction of dopamine in the corpus striatum of copper-deficient male rats. Consistent with altered in vivo dopamine β-monooxygenase activity, there were five-, three-, and twofold elevations of dopamine in cerebellum, medulla-pons, and hypothalamus of copper-deficient rats. Spectrophotometric measurement of in vitro dopamine β-monooxygenase activity of brain and adrenal homogenates was higher in copper-deficient rats, confirming prior work. An explanation for the in vitro data is unclear. Changes in copper and catecholamine levels were influenced by diet and were regionally selective, especially in the hypothalamus.     

The expression of cecropin peptide in transgenic tobacco does not confer resistance to Pseudomonas syringae pv tabaci

Summary We used in vitro growth inhibition assays to demonstrate that synthetic cecropin protein has potent activity against a range of plant pathogenic bacteria. We then prepared transgenic tobacco plants which express cecropin mRNA and protein. We have used Pseudomonas syringae pv tabaci infection of these transgenic tobacco as a model system to evaluate whether the plants which express cecropin protein also have increased tolerance to infection. We found no dramatic difference in disease response between plants which are expressing cecropin protein and control plants which were derived from the transformation with a binary vector which did not carry the gene encoding cecropin protein.