The natural fluorescence of wool

Wool may be excited by both mid-and near-u.v. radiation, emitting fluorescence. The extent of visible fluorescence depends on the origin of the wool and the degree of weathering, (the tips of the fibres being more fluorescent than the roots) and chemical modification. In particular oxidative treatments such as chlorination of shrink-resist procedures or peroxide bleaching processes increase the intensity of visible fluorescence but decrease the intensity of u.v. fluorescence (emission maximum at about 350 nm). It is proposed that the presence of these fluorescent chromophores in the fibre relates to the susceptibility of wool to yellow on exposure to light.     

Bidirectional transport by distinct populations of COPI-coated vesicles

Electron microscope immunocytochemistry reveals that both anterograde-directed (proinsulin and VSV G protein) and retrograde-directed (the KDEL receptor) cargo are present in COPI-coated vesicles budding from every level of the Golgi stack in whole cells; however, they comprise two distinct populations that together can account for at least 80% of the vesicles budding from Golgi cisternae. Segregation of anterograde- from retrograde-directed cargo into distinct sets of COPI-coated vesicles is faithfully reproduced in the cell-free Golgi transport system, in which VSV G protein and KDEL receptor are packaged into separable vesicles, even when budding is driven by highly purified coatomer and a recombinant ARF protein.     

Emotional memory and psychopathology

A leading model for studying how the brain forms memories about unpleasant experiences is fear conditioning. A cumulative body of work has identified major components of the neural system mediating this form of learning. The pathways involve transmission of sensory information from processing areas in the thalamus and cortex to the amygdala. The amygdala's lateral nucleus receives and integrates the sensory inputs from the thalamic and cortical areas, and the central nucleus provides the interface with motor systems controlling specific fear responses in various modalities (behavioural, autonomic, endocrine). Internal connections within the amygdala allow the lateral and central nuclei to communicate. Recent studies have begun to identify some sites of plasticity in the circuitry and the cellular mechanisms involved in fear conditioning. Through studies of fear conditioning, our understanding of emotional memory is being taken to the level of cells and synapses in the brain. Advances in understanding emotional memory hold out the possibility that emotional disorders may be better defined and treatment improved.     

Indicators of postoperative pain in cats and correlation with clinical criteria

OBJECTIVE: To identify clinical indicators that may help identity postoperative pain in cats after ovariohysterectomy. ANIMALS: Healthy, laboratory animal source cats. PROCEDURE: Clinical indicators of pain were identified, and relief from pain in response to butorphanol was studied in 5 groups of cats. 10 cats had 1 hour of general anesthesia only, followed by recovery without additional medication. 10 cats had general anesthesia and ovariohysterectomy, followed by recovery without additional medication. 10 cats had general anesthesia, ovariohysterectomy, and postoperative administration of 0.1 mg of butorphanol/kg of body weight. Another 10 cats had general anesthesia, ovariohysterectomy, and postoperative administration of 0.3 mg butorphanol/kg. 10 cats received 0.1 mg of butorphanol/kg, IM, only. Samples and recorded data were obtained before, during, and after the anesthesia period. Clinical variables measured included heart rate, blood pressure, respiratory rate, rectal temperature, PCV, and blood glucose concentration. Results were compared with changes in norepinephrine, epinephrine, and cortisol concentrations. RESULTS: Cats that did not receive analgesics had higher cortisol concentration than did cats without surgery and cats that received butorphanol after surgery. Systolic blood pressure measured by ultrasonic Doppler was found to be predictive of cortisol concentration, using a multiple linear regression model. CONCLUSIONS: Cortisol concentration increased in response to surgical stress and pain, and this increase was diminished by use of butorphanol. CLINICAL RELEVANCE: Systolic blood pressure was the best clinical predictor of postoperative pain.     

Fish immunology: the utility of immortalized lymphoid cells--a mini review

Long term cell lines can be readily established at high frequency with PBLs from normal channel catfish. Depending upon the mode of stimulation, morphologically and functionally distinct catfish lymphoid cell lines resembling B cells, T cells and monocytes have been developed. These fish cell lines appear unique from their putative mammalian counterparts in that they are immortalized without the need for exogenous factors or overt attempts at transformation.     

HIV protease inhibitory bis-benzamide cyclic ureas: a quantitative structure-activity relationship analysis

A series of N,N'-disubstituted cyclic urea 3-benzamides has been synthesized and evaluated for HIV protease inhibition and antiviral activity. Some of these benzamides have been shown to be potent inhibitors of HIV protease with Ki < 0.050 nM and IC90 < 20 nM for viral replication and, as such, may be useful in the treatment of AIDS. The synthesis and quantitative structure-activity relationship for this benzamide series will be discussed.     

Cloning, characterization, and properties of seven triplet repeat DNA sequences

Several neuromuscular and neurodegenerative diseases are caused by genetically unstable triplet repeat sequences (CTG.CAG, CGG.CCG, or AAG.CTT) in or near the responsible genes. We implemented novel cloning strategies with chemically synthesized oligonucleotides to clone seven of the triplet repeat sequences (GTA.TAC, GAT.ATC, GTT.AAC, CAC.GTG, AGG.CCT, TCG.CGA, and AAG.CTT), and the adjoining paper (Ohshima, K., Kang, S., Larson, J. E., and Wells, R. D.(1996) J. Biol. Chem. 271, 16784-16791) describes studies on TTA.TAA. This approach in conjunction with in vivo expansion studies in Escherichia coli enabled the preparation of at least 81 plasmids containing the repeat sequences with lengths of approximately 16 up to 158 triplets in both orientations with varying extents of polymorphisms. The inserts were characterized by DNA sequencing as well as DNA polymerase pausings, two-dimensional agarose gel electrophoresis, and chemical probe analyses to evaluate the capacity to adopt negative supercoil induced non-B DNA conformations. AAG.CTT and AGG.CCT form intramolecular triplexes, and the other five repeat sequences do not form any previously characterized non-B structures. However, long tracts of TCG.CGA showed strong inhibition of DNA synthesis at specific loci in the repeats as seen in the cases of CTG.CAG and CGG.CCG (Kang, S., Ohshima, K., Shimizu, M., Amirhaeri, S., and Wells, R. D.(1995) J. Biol. Chem. 270, 27014-27021). This work along with other studies (Wells, R. D.(1996) J. Biol. Chem. 271, 2875-2878) on CTG.CAG, CGG.CCG, and TTA.TAA makes available long inserts of all 10 triplet repeat sequences for a variety of physical, molecular biological, genetic, and medical investigations. A model to explain the reduction in mRNA abundance in Friedreich's ataxia based on intermolecular triplex formation is proposed.