Oxygen distribution and vascular injury in the mouse eye measured by phosphorescence-lifetime imaging

Maps of the oxygen distribution in the retina of the mouse eye were obtained by phosphorescence-lifetime imaging. Phosphor dissolved in the blood was excited by modulated light and phosphorescence imaged through microscope optics with an intensified-CCD camera. Phosphorescence lifetimes and oxygen pressures were calculated for each pixel of the images. The resolution was sufficient to permit the detection of anomalies that result in reduced oxygen pressures in individual retinal capillaries. High-resolution maps of oxygen distribution in the retina can provide greater understanding of the role of oxygen and vascular function in diseases of the eye.     

Aggregation studies of humic acid using multiangle laser light scattering

An aqueous phase study of the naturally occurring dissolved organic carbon humic acid (HA) is performed using multiangle laser light scattering (MALLS) to measure its RMS radius and average molecular weight. A Zimm plot using Berry Formulism and a second-order fit gave an average molar mass of 1.164 x 10(8) g/mol and an average RMS radius (Rz) of 436.0 +/- 36 nm at 25 degrees C.     

Raman spectroscopic method for identification of clinically relevant microorganisms growing on solid culture medium

Routine clinical microbiological identification of pathogenic microorganisms is largely based on nutritional and biochemical tests. In the case of severely ill patients, the unavoidable time delay associated with such identification procedures can be fatal. We present a novel identification method based on confocal Raman microspectroscopy. With this approach it is possible to obtain Raman spectra directly from microbial microcolonies on the solid culture medium, which have developed after only 6 h of culturing for the most commonly encountered organisms. Due to the limited thickness of microcolonies, some of the underlying culture medium is sampled together with the bacteria. Spectra measured at different depths in a microcolony contain different amounts of the medium signal. A mathematical routine, involving vector algebra, is described for the nonsubjective correction of spectra for variable signal contributions of the medium. To illustrate the possibilities of our approach for the identification of microorganisms, Raman spectra were collected from 6-h microcolonies of five bacterial strains on solid culture medium. The classification results show that confocal Raman microspectroscopy has great potential as a powerful new tool in clinical diagnostic microbiology.     

The piano: A modern film melodrama about passion and punishment.

Melodrama has been the dominant form of moviemaking for women, and the recent Jane Campion film, The Piano (J. Chapman & J. Campion, 1993), is a lush modern representation. Central to this film is the struggle of Ada to choose between passion and security, between life and death, in a primitive New Zealand environment. Campion adds many modern elements to this genre, creating a complex fictional character who evokes powerful psychological responses in the other characters and in the audience. A psychoanalytic perspective sheds some light on the nuances and power of this film as it uses silence, emerging sexuality, primal scene anxiety, and romantic salvation to stimulate the audience. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Possible dangers of anaesthesia in patients receiving fenfluramine. Results of animal studies following a case of human cardiac arrest

Following the report of the death of a patient concurrently taking fenfluramine, following routine general anaesthesia, a series of anaesthetised rabbits received injections of adrenaline or fenfluramine. There were abnormal electrocardiographic changes and phonocardiographic evidence of altered heart activity in both groups, but the changes seen with fenfluramine were greater in number and less readily reversed with beta blockers and resuscitative drugs. This evidence may support an interaction between halothane and fenfluramine in man, and it is suggested that the latter drug be discontinued for a week prior to anaesthesia for elective surgery.     

Isolation of a member of the neurotoxin/cytotoxin peptide family from Xenopus laevis skin which activates dihydropyridine-sensitive Ca2+ channels in mammalian epithelial cells

We have used a sensitive bioassay of calcium-mediated volume changes in mammalian absorptive intestinal epithelial cells to screen extracts of the skin of the amphibian Xenopus laevis for the presence of factors affecting ion transport. A 66-residue peptide, purified using reversed-phase high performance liquid chromatography techniques, caused isotonic volume reduction of guinea pig jejunal villus cells in suspension. This volume reduction required extracellular Ca2+ and was prevented by the dihydropyridine-sensitive Ca2+ channel blocker niguldipine. Structural analysis demonstrated the presence of eight cysteines and a primary structure homologous to that of the neurotoxin/cytotoxin family found in the venom of certain poisonous snakes. The structure of the peptide was identical to that of xenoxin-1 purified from dorsal gland secretions of X. laevis (Kolbe, M., Huber A., Cordier, P., Rasmussen, U., Bouchon, B., Jaquinod, M., Blasak, R., Detot, E., and Kreil, G. (1993) J. Biol. Chem. 268, 16458-16464). Xenoxin-1 (10 nM) caused volume changes that required extracellular Ca2+ and were comparable in magnitude and direction to changes caused by BayK-8644 (100 nM), a dihydropyridine-sensitive Ca2+ channel agonist. The initial rate of dihydropyridine-sensitive 45Ca2+ influx was substantially increased by xenoxin-1. Staurosporine (10 nM) prevented volume changes caused by ATP (250 microM) but had no effect on volume changes caused by BayK-8644 or xenoxin-1. We conclude that xenoxin-1 directly activated dihydropyridine-sensitive Ca2+ channels in villus cells and that a mammalian homologue to xenoxin-1 may exist.     

A sensitive period for the maintenance of emotionality in Mongolian gerbils.

Gerbils reared and continuously housed in cages providing access to shelter respond throughout life to sudden visual stimulation by fleeing, hiding, and foot thumping. In the present 5 experiments with a total of 788 gerbils, Ss reared and housed in cages lacking shelter exhibited this pattern of response to stimulation at 26 and 31 days of age but not at greater ages. During a limited period (Days 30–60 after birth) experience with shelter was sufficient to maintain reactivity to stimulation, but similar experience with shelter at 21, 90, or 126 days of age was not sufficient to do so. These findings indicate (a) that shelter experience is a necessary condition for the maintenance of enhanced reactivity to stimulation but not for its development and (b) that gerbils are not equally sensitive to shelter experience throughout life. (17 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Relatively brief environmental enrichment aids recovery of learning capacity and alters brain measures after postweaning brain lesions in rats.

Two experiments showed that enriched postlesion experience aided in overcoming effects of simultaneous bilateral cerebral lesions made at 30 days of age in 64 male inbred Fischer rats (Exp I) and 60 male Berkeley S-sub-1 rats (Exp II). The lesions were directed to the occipital cortex, but in most cases there was also some impairment of the hippocampus. For 60 days after operations, half of the Ss lived in small individual cages and half lived in groups in large enriched-environment cages. They were then pretrained and tested on the standard 12 Hebb-Williams problems. Daily injections of methamphetamine (vs saline) during the period of differential experience in Exp I had no effect on the behavioral scores. Exp II included groups that received only 2 hrs/day of enriched experience, and they benefited as much as groups that remained in the enriched environment 24 hrs/day. Results demonstrate significant beneficial effects of environment when bilateral lesions were made at a later age and when the periods of enriched experience were shorter than have previously been tested. Two additional experiments with 112 Berkeley S-sub-1 rats revealed significant effects of both lesions and environment on weight and RNA/DNA of brain regions. (33 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Ocular manifestations of toxic epidermal necrolysis associated with allopurinol use

A 54-year-old man was receiving allopurinol therapy to treat hyperuricemia that followed an inferior wall, myocardial infarction. After three weeks of allopurinol therapy, the patient developed signs and symptoms of toxic epidermal necrolysis that included pseudomembranous conjunctivitis with ulcerative lesions on the lids and conjunctiva, and punctate corneal staining with subsequent corneal abrasions. Treatment with topical antibiotics and artificial tears relieved the symptoms somewhat, but punctate staining and dry eyes persisted after 14 months of follow-up. Bilateral corneal ulcers developed and necessitated conjunctival flaps in each eye. Visual acuity in each eye was 20/40.