Cortical transients preceding voluntary movement.

The process of initiating a voluntary muscular movement evidently involves a focusing of diffuse brain activity onto a highly specific location in the primary motor cortex. Even the very simple stereotypic movements used to study the 'contingent negative variation' and the 'readiness potential' begin with EEG indicative of widely distributed brain activity. In natural settings the involvement of diffuse cortical networks is undoubtedly even more important. Eventually, however, activity must coalesce onto specific neurons for the intended movement to ensue. Here we examine that focusing process from a mathematical point of view. Using a digital simulation, we solve the global equations for cortical dynamics and model the flow from diffuse onset to localized spike. From this perspective the interplay between global and local effects is seen as a necessary consequence of a basic cortical architecture which supports wave propagation. Watching the process evolve over time allows us to estimate some characteristic amplitudes and delays.

The co-ordination of central plant metabolism by the circadian clock.

A circadian clock optimizes many aspects of plant biology relative to the light/dark cycle. One example is the circadian control of primary metabolism and CO2 fixation in plants that carry out a metabolic adaptation of photosynthesis called CAM (crassulacean acid metabolism). These plants perform primary CO2 fixation at night using the enzyme phosphoenolpyruvate carboxylase and exhibit a robust rhythm of CO2 fixation under constant conditions. Transcriptomic analysis has revealed that many genes encoding enzymes in primary metabolic pathways such as glycolysis and starch metabolism are under the control of the circadian clock in CAM plants. These transcript changes are accompanied by changes in metabolite levels associated with flux through these pathways. The molecular basis for the circadian control of CAM remains to be elucidated. Current research is focusing on the identity of the CAM central oscillator and the output pathway that links the central oscillator to the control of plant metabolism.

Observations on the background spectra of four LaCl 3 Ce scintillation detectors.

Our laboratory has purchased four LaCl (3)(Ce) scintillation crystals over the course of the last year for evaluation as part of an environmental management research and development project. In addition to the expected content of naturally radioactive (138)La, we have found that all four of these detectors are contaminated to various degrees with alpha particle emitting nuclides that we have determined to be (227)Ac and its daughters. The impact of these radionuclides on the background spectra and, thus, on the detection sensitivity of these detectors is presented and discussed.

Differential transduction efficiency of SCID-repopulating cells derived from umbilical cord blood and granulocyte colony-stimulating factor-mobilized peripheral blood.

The gene transfer efficiency into nonobese diabetic/severe combined immunodeficient (NOD/SCID)-repopulating cells (SRCs) derived from umbilical cord blood (UCB) (n = 11 NOD/SCID mice) and granulocyte-colony stimulating factor (G-CSF)-mobilized peripheral blood (MPB) (n = 64 NOD/SCID mice) was compared using a clinically relevant protocol and a retrovirus vector expressing the enhanced green fluorescent protein (EGFP). At 6-9 weeks after transplantation, the frequency of transduced human cells in the bone marrow (BM) (40.5% +/- 2.4% [mean +/- SE]) and spleen (SPL) (36.4% +/- 3.2%) in recipients of UCB cells was significantly higher (p < 0.001) than that observed in the BM (2.2% +/- 1.8%) and SPL (2.0% +/- 2.6%) in recipients of MPB. In subsequent studies, MPB was cultured for 2-8 days in cytokines prior to transduction to determine if longer prestimulation was required for optimal gene transfer. A significant increase in gene transfer into CD45(+) human cells and clonogenic cells derived from MPB SRCs was observed when cells were prestimulated for 6 days compared to 2 days prior to transduction (p = 0.019). However, even after 6 days of prestimulation, transduction was still significantly less than UCB. A substantial discrepancy exists in the ability to introduce genes effectively via retrovirus vectors into SRCs derived from MPB as compared to UCB.

Rumen undegradable protein, rumen-protected choline and mRNA expression for enzymes in gluconeogenesis and ureagenesis in periparturient dairy cows.

The objective of this study was to profile mRNA expression of argininosuccinate synthetase (AS) and ornithine transcarbamylase (OTC), two enzymes that participate in the formation of urea in liver and compare these with changes in mRNA for pyruvate carboxylase (PC) and phosphoenolpyruvate carboxykinase (PEPCK) during the periparturient period in dairy cows. Forty-eight multiparous Holstein cows were fed isoenergetic prepartum diets that contained 10% RDP and either 4.0% RUP or 6.2% RUP and either 0, 6, or 12 g/d of rumen-protected choline (RPC) as CapShure (Balchem Corp., Slate Hill, NY). After calving cows received a common diet and continued RPC as per their prepartum assignments. Liver biopsies were obtained on d -28, -14, 1, 28, and 56 relative to calving, and the abundances of AS, OTC, PC, PEPCK, and 18S mRNA were determined by Northern blot analysis of total RNA. The abundance of OTC mRNA was lowest at calving and was decreased by RPC and 6.2% RUP feeding. Feeding 6.2% RUP did not alter AS, PC, or PEPCK mRNA. The expression of AS mRNA increased and PEPCK mRNA tended to increase from calving to 56 DIM. Pyruvate carboxylase mRNA increased more than twofold at calving. The data indicated adaptation to lactation for gluconeogenic enzymes that is not matched in direction and magnitude by changes in mRNA for urea cycle enzymes. Feeding additional protein, as RUP, failed to induce mRNA for key enzymes in gluconeogenesis or ureagenesis.

Modification of the University of Washington Neutron Radiotherapy Facility for optimization of neutron capture enhanced fast-neutron therapy.

A modified neutron production target assembly has been developed to provide improved performance of the proton-cyclotron-based neutron radiotherapy facility at the University of Washington for applications involving neutron capture enhanced fast-neutron therapy. The new target produces a neutron beam that yields essentially the same fast-neutron physical depth-dose distribution as is produced by the current UW clinical system, but that also has an increased fraction of BNCT enhancement relative to the total therapeutic dose. The modified target is composed of a 5-millimeter layer of beryllium, followed by a 2.5-millimeter layer of tungsten, with a water-cooled copper backing. Measurements of the free-field neutron spectrum of the beam produced by the new target were performed using activation foils with a direct spectral unfolding technique. Water phantom measurements were performed using a tissue-equivalent ion chamber to characterize the fast-neutron depth-dose curve and sodium activation in soda-lime glass beads to characterize the thermal-neutron flux (and thus the expected neutron capture dose enhancement) as a function of depth. The results of the various measurements were quite consistent with expectations based on the design calculations for the modified target. The spectrum of the neutron beam produced by the new target features an enhanced low-energy flux component relative to the spectrum of the beam produced by the standard UW target. However, it has essentially the same high-energy neutron flux, with a reduced flux component in the mid-range of the energy spectrum. As a result, the measured physical depth-dose curve in a large water phantom has the same shape compared to the case of the standard UW clinical beam, but approximately twice the level of BNCT enhancement per unit background neutron dose at depths of clinical interest. In-vivo clinical testing of BNCT-enhanced fast-neutron therapy for canine lung tumors using the new beam was recently initiated.

Impact of dietary rumen undegradable protein and rumen-protected choline on intake, peripartum liver triacylglyceride, plasma metabolites and milk production in transition dairy cows.

The objectives of the present study were to determine the effects of rumen undegradable protein (RUP) level of prepartum diets, the supplementation of a rumen-protected choline product, and their interactions on milk production, feed intake, body weight and condition, blood metabolites, and liver triacylglycerides in dairy cows. Rumen-protected choline (RPC) was fed with two levels of RUP to 48 multiparous Holstein cows in a 3 x 2 factorial arrangement of treatments. Beginning 28 d before expected calving, cows were fed 10% rumen degradable protein, either 0, 6, or 12 g/d of RPC as CapShure (Balchem Corp., Slate Hill, NY) and either 4.0 or 6.2% RUP. After calving and through 120 d of lactation, cows received a common diet and continued RPC as per their prepartum assignment. Prepartum dry matter intake (kg/d) was not affected by RPC or RUP. Postpartum intake decreased when 6.2% RUP was fed prepartum. Milk production to 56 d in milk was decreased when cows were fed 6.2% RUP prepartum. Milk protein (kg/d) decreased when additional RUP was fed prepartum. Cows fed RPC lost more weight during the study period and tended to lose more body condition. Plasma urea nitrogen levels in the prepartum period were reduced for cows fed 4.0% RUP prepartum. Mean liver triacylglyceride determined from samples obtained at -28, -14, +1, +28, and +56 d in milk was not affected by RPC, prepartum RUP, or their combinations. Feeding 12 g of RPC/d in conjunction with 4.0% RUP increased milk production, but feeding RPC with 6.2% RUP prepartum and through 56 d in milk decreased production. The data indicate that 6.2% RUP does not benefit close-up dry cows, and the response to RPC depends the RUP content of the prepartum diet.

Phosphoenolpyruvate carboxylase kinase is a novel protein kinase regulated at the level of expression.

Phosphorylation of phosphoenolpyruvate carboxylase plays a key role in the control of plant metabolism. Phosphoenolpyruvate carboxylase kinase is a Ca2+-independent enzyme that is activated by a process involving protein synthesis in response to a range of signals in different plant tissues. The component whose synthesis is required for activation has not previously been identified, nor has the kinase been characterised at a molecular level. We report the cloning of phosphoenolpyruvate carboxylase kinase from the Crassulacean Acid Metabolism plant Kalanchoë fedtschenkoi and the C3 plant Arabidopsis thaliana. Surprisingly, phosphoenolpyruvate carboxylase kinase is a member of the Ca2+/calmodulin-regulated group of protein kinases. However, it lacks the auto-inhibitory region and EF hands of plant Ca2+-dependent protein kinases, explaining its Ca2+-independence. Its sequence is novel in that it comprises only a protein kinase catalytic domain with no regulatory regions; it appears to be the smallest known protein kinase. In K. fedtschenkoi, the abundance of phosphoenolpyruvate carboxylase kinase transcripts increases during leaf development. The transcript level in mature leaves is very low during the photoperiod, reaches a peak in the middle of the dark period and correlates with kinase activity. It exhibits a circadian oscillation in constant conditions. Protein kinases are typically regulated by second messengers, phosphorylation or protein/protein interactions. Phosphoenolpyruvate carboxylase kinase is an exception to this general rule, being controlled only at the level of expression. In K. fedtschenkoi, its expression is controlled both developmentally and by a circadian oscillator.

Metabolite Control Overrides Circadian Regulation of Phosphoenolpyruvate Carboxylase Kinase and CO(2) Fixation in Crassulacean Acid Metabolism.

Phosphoenolpyruvate carboxylase (PEPc) catalyzes the primary fixation of CO(2) in Crassulacean acid metabolism plants. Flux through the enzyme is regulated by reversible phosphorylation. PEPc kinase is controlled by changes in the level of its translatable mRNA in response to a circadian rhythm. The physiological significance of changes in the levels of PEPc-kinase-translatable mRNA and the involvement of metabolites in control of the kinase was investigated by subjecting Kalanchoë daigremontiana leaves to anaerobic conditions at night to modulate the magnitude of malate accumulation, or to a rise in temperature at night to increase the efflux of malate from vacuole to cytosol. Changes in CO(2) fixation and PEPc kinase activity reflected those in kinase mRNA. The highest rates of CO(2) fixation and levels of kinase mRNA were observed in leaves subjected to anaerobic treatment for the first half of the night and then transferred to ambient air. In leaves subjected to anaerobic treatment overnight and transferred to ambient air at the start of the day, PEPc-kinase-translatable mRNA and activity, the phosphorylation state of PEPc, and fixation of atmospheric CO(2) were significantly higher than those for control leaves for the first 3 h of the light period. A nighttime temperature increase from 19 degrees C to 27 degrees C led to a rapid reduction in kinase mRNA and activity; however, this was not observed in leaves in which malate accumulation had been prevented by anaerobic treatment. These data are consistent with the hypothesis that a high concentration of malate reduces both kinase mRNA and the accumulation of the kinase itself.

2',5'-linked oligo-3'-deoxyribonucleoside phosphorothioate chimeras: thermal stability and antisense inhibition of gene expression.

2',5'-Linked oligo-3'-deoxyribonucleotides bind selectively to complementary RNA but not to DNA. These oligonucleotides (ODNs) do not recognize double-stranded DNA by Hoogsteen triplex formation and the complexes formed by these ODNs with RNA are not substrates for Escherichia coli RNase H. Substitution of the 2',5'-phosphodiester backbone by phosphorothioate linkages gives 2',5'-linked oligo-3'-deoxynucleoside phosphorothioate ODNs that exhibit significantly less non-specific binding to cellular proteins or thrombin. Incorporation of a stretch of seven contiguous 3',5'-linked oligo-2'-deoxynucleoside phosphorothioate linkages in the center of 2',5'-linked ODNs (as a putative RNase H recognition site) afford chimeric antisense ODNs that retain the ability to inhibit steroid 5alpha-reductase (5alphaR) expression in cell culture.

Early memories and maladjustment.

Earliest memories were elicited from 60 undergraduates, who also completed the Rotter Incomplete Sentences Blank, Symptom Checklist-90-Revised, Wahler Physical Symptoms Inventory, and Marlowe-Crowne Social Desirability Scale. Early memories were scored for the three factors identified by Caruso and Spirrison (Emotional Poise, Activity, and Dependability). These scores were not significantly associated with indices of maladjustment or the social desirability measure. Age at reported earliest memory was significantly related to maladjustment, with persons reporting first memories prior to 4 years of age having significantly higher scores on maladjustment, as measured by the Rotter Incomplete Sentences Blank, than individuals with first memories occurring later. Individuals whose first memories occurred after the age of 5 years reported significantly more somatic concerns than persons with early memories of average onset, i.e., 4 to 5 years of age.

Effects of buspirone and diazepam, alone and in combination with alcohol, on skilled performance and evoked potentials.

Effects of buspirone, 10 and 20 mg, and diazepam, 10 mg, on skilled performance and evoked responses, as well as their interactions with 0.8 g/kg of alcohol were investigated in 24 healthy men. Alcohol, 0.8 g/kg, caused the greatest performance impairment, followed closely by diazepam. Both doses of buspirone had lesser effects. Buspirone had primarily sedative effects which were short lasting, whereas diazepam impaired tracking and body balance in addition to being sedative. Both anxiolytics showed only slight additive interactions with the present dose of alcohol. A strong drug effect and a lesser but significant alcohol and a drug/alcohol interaction effect were seen on evoked potentials. Diazepam effects on evoked potentials were similar to alcohol, whereas buspirone in some instances appeared to reverse the alcohol effect. Pharmacokinetics of buspirone and diazepam were not significantly affected by concomitant administration of alcohol. The psychomotor side effect profile of a single anxiolytic dose of buspirone is preferable to a single 10-mg dose of diazepam.

Evoked potential analysis: on-line signal optimization using a mini-computer.

An automated computer-based system is described for the analysis of evoked potentials. All procedures are carried out in real-time A small computer performs the following functions; timing of random stimulus presentation, rejection of artifact contaminated responses, collection of digital data, computation of averaged evoked responses, computation of the Wiener filter, storage of the filtered and unfiltered averages and display of the resultant averages. The Wiener filter as described by Walter (1969) and Doyle (1975) is used to improve the estimate of the evoked potential by discriminating against frequencies likely to be contaminated with noise. The defining equation for the Wiener filter states that information at any frequency is to be weighted by the ratio of the power known to be in the signal (response) at that frequency over the corresponding power known to be in both the signal (response) and the noise (background EEG) at the same frequency. The technique requires the computation of the Fourier transform for each response in order to produce the power spectra necessary for the Wiener filter. Earlier reports dealing with this technique have usee large computers to analyze the evoked potential data off-line. The system described here allows for greater routine utilization of this powerful technique and the concomitant automated rejection of artifact contaminated responses. Highly improved estimates of the evoked potential are resultant using a minimal number of stimuli.

Types of anticancer agents isolated from plants.

The active compounds which have been isolated from plants and tested in the chemotherapy program of the National Cancer Institute since the inception of the plant program (as part of the Cancer Chemotherapy National Service Center) are listed, classified into types, and discussed in terms of their activity in experimental tumor systems. The tumor systems include the most important ones comprising the regular screen at different times and also the slow-growing tumors, B16 melanoma and Lewis lung carcinoma (new). The structure-antitumor activity relationships bring out the desirability for further investigation of certain types of compounds as possibilities for clinical trial. Notes on the current pharmacologic anc clinical status of certain compounds are also presented.