The marine toxin okadaic acid reduces O2- generation and tyrosine phosphorylation in LPS-primed rat neutrophils

Contrasting effects of okadaic acid (OKA) on neutrophil (PMN) superoxide anion (O2-) generation have been reported. In this study, we examined the effect of OKA on phorbol myristate acetate (PMA)-stimulated O2- generation in rat PMNs primed with LPS in vivo (LPS-PMN) and saline-treated rat PMNs (SAL-PMN). The following results were observed: (1) OKA, but neither genistein nor vanadate, markedly reduced O2- generation in a dose and time-dependent manner; (2) genistein, a tyrosine kinase inhibitor, as well as OKA, reduced tyrosine phosphorylation; (3) sodium orthovanadate, a tyrosine phosphatase inhibitor, potently enhanced tyrosine phosphorylation. Our studies suggest that OKA might reduce tyrosine phosphorylation by affecting the activity of tyrosine phosphatases regulated by serine-threonine phosphorylation.     

Isolation and sequence of the gene encoding ornithine decarboxylase, SPE1, from Candida albicans by complementation of a spe1 delta strain of Saccharomyces cerevisiae

The gene encoding ornithine decarboxylase, SPE1, from the pathogenic yeast Candida albicans has been isolated by complementation of an ornithine decarboxylase-negative (spe1 delta) strain of Saccharomyces cerevisiae. Four transformants, three of which contain plasmids with the SPE1 gene, were isolated by selection on polyamine-free medium. The C. albicans ornithine decarboxylase (ODC) showed high homology with other eukaryotic ODCs at both the amino acid and nucleic acid levels.     

Preventive services in a Medicare managed care environment

The results of a four year demonstration project of preventive services for Medicare managed care enrollees suggest that health promotion programs can impact health behaviors and outcomes. The study provided selected preventive services to 1,800 Medicare enrollees in a managed care environment. Participants were randomly assigned to control and experimental groups with the experimental group receiving an intervention service package and the control group usual care. The results included enhanced health behavior practices, lower depression, and higher immunization rates among those individuals in the experimental group. This study suggests that selected preventive services can be provided in a managed care environment to Medicare enrollees with likely positive health status and utilization outcomes.     

Changes in neural modulation and motor control during voluntary movement of older individuals

BACKGROUND: Changes in the modulation of soleus alpha motoneuron excitability, as assessed by H reflexes, and temporal sequencing of the soleus and tibialis anterior muscles during voluntary ankle dorsiflexions and plantar flexions of young (24.7 +/- 11.5; n = 13) and older (68.7 +/- 5.4; n = 13) subjects were assessed to determine potential neural mechanisms that might contribute to motor control changes associated with aging. METHODS: A repetitive stimulation (5 Hz) soleus H-reflex testing protocol and surface electromyography (EMG) were used to assess the latencies of soleus H-reflex changes in relation to tibialis anterior and soleus EMG activations of standing subjects during voluntary ankle dorsiflexions and plantar flexions at self-selected speeds. The pattern and latency of H-reflex changes in relation to EMG activity were compared between young and old subjects. RESULTS: There were no differences in the relative amount of antagonist muscle (soleus) inhibition during voluntary ankle dorsiflexions between young and old subjects (26.4% and 27.2% decrease from resting H-reflex values, respectively). Older subjects, however, required additional time to achieve these levels of inhibition. Delays in the activation of soleus H reflexes during the plantar flexion task were also observed in older subjects. Older subjects also had considerable intra- and intersubject variability in muscle temporal sequencing patterns during ankle plantar flexions. CONCLUSIONS: Although older subjects exhibited similar relative levels of alpha motoneuron inhibition and excitation during voluntary movements, this modulation was delayed when compared to younger subjects. Temporal sequencing of distal muscle activations also appears to undergo change with aging.     

Expression of de novo high-lysine alpha-helical coiled-coil proteins may significantly increase the accumulated levels of lysine in mature seeds of transgenic tobacco plants

Transgenic insect technology will provide opportunities to explore the basic biology of a broad range of insect species in ways that will prove insightful and important. It is also a technology that will provide opportunities to manipulate the genotypes of insects of practical significance to the health and welfare of humans. The Hermes transposable element from the housefly, Musca domestica, is a short inverted repeat-type element related to hobo from Drosophila melanogaster, Ac from Zea mays, and Tam3 from Antirrhinum majus. It has potential to become a versatile and efficient broad host-range insect transformation vector. The ability of Hermes to transpose when introduced into five species of diptera from four divergent families was tested using an in vivo, interplasmid transpositional recombination assay. Hermes was capable of transposing in all species tested, demonstrating that Hermes has a broad host-range. In addition, the rates of transposition were sufficiently high in all species tested to suggest that Hermes will be an efficient gene transfer vector in a wide range of insect species. The Hermes element also revealed a pattern of integration into the target substrate that permitted factors determining integration site selection to be identified. Primary nucleotide sequence of the integration site played a role as did proximity to preferred integration sites and the nucleosomal organization of the target.     

In situ compositional analysis of acidocalcisomes in Trypanosoma cruzi

We measured the elemental content of different compartments in Trypanosoma cruzi epimastigotes using quick freezing, ultracryomicrotomy, and electron probe microanalysis. Vacuoles identified by high electron density contained (in units of mmol/kg dry weight +/- S.E.) large amounts of phosphorus (1390 +/- 13), magnesium (646 +/- 19), calcium (171 +/- 5), sodium (161 +/- 18), and zinc (148 +/- 6). No other compartment had appreciable calcium or zinc content. Iron (128 +/- 16 mmol/kg) was detected only in vacuoles distinct from the electron-dense vacuoles and other organelles. Incubation of cells for 70 min in culture medium in the presence of ionomycin plus nigericin led to a very significant 3- or 2-fold increase in potassium in the electron-dense vacuoles and the iron-rich vacuoles, respectively, with no significant change in the other elements investigated. This indicated the acidic nature of the vacuoles and demonstrated that the electron-dense vacuoles correspond to what were described previously as acidocalcisomes, i.e. acidic compartments rich in Ca2+. The acidocalcisomes were investigated by separation of epimastigote fractions on Percoll gradients in combination with Triton WR-1339 treatment. This detergent caused a rapid vacuolation; these vacuoles were shown by electron microscopy to be largely transparent, with a diffuse matrix. Percoll gradient fractionation demonstrated decreases in the density of various organelle markers in detergent-treated cells compared with controls. Large decreases in the density of the acidocalcisome and the mitochondrion were seen, as well as smaller decreases in the density of the other markers. Conventional electron microscopy of epimastigotes loaded with gold-labeled transferrin indicated that the endosomal system was separate from vacuoles that probably corresponded to the calcium-containing organelles detected by electron probe microanalysis. The combined results provide evidence that acidocalcisomes are organelles different from lysosomes or other organelles previously described in these parasites.     

Gas chromatographic/mass spectrometric analyses of unknown analytical response in imported Fava beans: 4-chloro-6-methoxyindole

A halogenated unidentified analytical response (UAR) was encountered in a number of imported Fava bean samples during the Food and Drug Administration's routine pesticide-monitoring program. Gas chromatographic/mass spectrometric (GC/MS) analyses identified the halogenated component as 4-chloro-6-methoxyindole, a naturally occurring promutagen in Fava beans that has been linked to incidents of gastric cancer. Data from electron impact, positive and negative chemical ionization, collision-induced dissociation, and deuteration studies of this compound are presented, along with GC retention time data.     

High resolution MR imaging of joint degeneration in the knee of the STR/ORT mouse

MR imaging of the knee joints of the mouse at 2.35 T produces an in-plane resolution of 35 x 70 microns and a slice thickness of 600 microns from the sagittal and coronal planes, in less than 60 min. In normal, live DBA mice, which have no known pathology, the images clearly resolve many joint structures, such as the cruciate ligaments, menisci, and articulating surfaces of the femur and tibia. Gross pathological changes were identified first in excised knees from cadaver mice of the STR/ORT strain. Males of this strain spontaneously exhibit rapid joint degeneration with increasing age compared to females, in which much milder symptoms develop more slowly. Thickening of the patellar tendon, displacement of the patella, deformity, and sclerosis were clearly distinguishable in males compared with females older than 7 mo of age. The same degenerative features were evident in MR images of the knees of the live male but not female STR/ORT mice of this age, indicating that it would be possible to monitor longitudinally by MR imaging progressive development of joint changes in this osteoarthritic model.     

Media literacy perspectives

Media literacy education involves cognitive processes used in critical thinking. Media workshops and curricula emphasize moral values (the defensive, inoculation approach), discriminating responsiveness (the critical viewer), antimedia resistance, and consumer revolution. Inductive media literacy programs promote independent critical thinking. Media content is a limited predictor of potential effects of media exposure. Meaning is situated in what audiences bring to their media experience (selective perception), the context in which they use media (accommodation), and how and why they use the medium (use and gratifications). To succeed, a curricular program of media literacy requires collaboration among teachers, administrators, specialists, and parents.