Many aspects of neuronal activity are regulated by calcium signals. The transduction of temporally and spatially distinct calcium signals requires the action of calcium sensor proteins including various EF-hand containing calcium-binding proteins. The Neuronal Calcium Sensor (NCS) family proteins have begun to emerge as key players in neuronal function. Many of these proteins are expressed predominantly or only in neurons sometimes with cell-specific patterns of expression. The NCS protein family is encoded by 14 genes in the human genome that possess four EF hand domains of which 2 or 3 bind calcium. The NCS proteins are high-affinity calcium-binding proteins that act as calcium sensors rather than calcium buffers as they undergo conformational changes on calcium-binding and regulate target proteins. Their ability to associate with membranes either constitutively or in response to calcium elevation allows the NCS proteins to discriminate between different spatial and temporal patterns of calcium signals. Several of the NCS proteins show changes in expression levels in specific disease states. Recent work has established several physiological roles of these proteins including diverse actions on gene expression, ion channel function, membrane traffic of ion channels and receptors and in the control of apoptosis. The NCS proteins act as calcium sensors for diverse functions and also as regulators of calcium signals through their effects on ion channels.

, Using confocal imaging of Rhod-2-loaded HeLa cells, we examined the ability of mitochondria to sequester Ca 2 1 signals arising from different sources. Mitochondrial Ca 2 1 (Ca 2 1 mit ) uptake was stimulated by inositol 1,4,5-trisphosphate (InsP 3 )-evoked Ca 2 1 release, capacitative Ca 2 1 entry, and Ca 2 1 leaking from the endoplasmic reticulum. For each Ca 2 1 source, the relationship between cytosolic Ca 2 1 (Ca 2 1 cyt ) concentration and Ca 2 1 mit was complex. With Ca 2 1 cyt < 300 n M , a slow and persistent Ca 2 1 mit uptake was observed. If Ca 2 1 cyt increased above ; 400 n M , Ca 2 1 mit uptake accelerated sharply. For equivalent Ca 2 1 cyt increases, the rate of Ca 2 1 mit rise was greater with InsP 3 -evoked Ca 2 1 signals than any other source. Spatial variation of the Ca 2 1 mit response was observed within individual cells. Both the fraction of responsive mitochondria and the amplitude of the Ca 2 1 mit response were graded in direct proportion to stimulus concentration. Trains of repetitive Ca 2 1 oscillations did not maintain elevated Ca 2 1 mit levels. Only low frequency Ca 2 1 transients ( < 1/15 min) evoked repetitive Ca 2 1 mit signals. Our data indicate that there is a lag between Ca 2 1 cyt and Ca 2 1

Sutcliffe, J.; Jacobson, M.; Brockman, G.; Berridge, M.; Saunders, C. A.B.; Marsden, P. K.; O'Doherty, M. J.; Maisey, N. M. Author Information

Ca2+ wave initiation and non-propagating Ca2+ spikes occur as a result of localized Ca2+ release from the more sensitive intracellular Ca2+ stores. Using high spatial and temporal Ca2+ -imaging techniques we have investigated inositol 1,4,5 triphosphate (InsP3)-induced local Ca2+ spiking, which occurs at the site of Ca2+ wave initiation in pancreatic acinar cells. The spatial and temporal organization of a single spike suggested discrete hot spots of Ca2+ release. Further analysis of long trains of Ca2+ spikes demonstrated that these hot spots showed regenerative Ca2+ -release events which were consistently active from spike to spike. Regions adjacent to these hot spots also showed regenerative Ca2+ -release events of similar amplitude but with a much lower frequency of occurrence. We conclude that the InsP3-induced non-propagating Ca2+ spikes can be devolved into smaller components of release. Our results are consistent with a model of coordinated activity of pacemaker hot spots of Ca2+ release that recruit and entrain active Ca2+ -release events from surrounding regions.

Head rotation, shoulder extension and rotation, ankle plantar and dorsiflexion, hip flexion, and sit and reach (SR) scores were examined in 41 women and 39 men, aged 45-75 years. The SR gave more reproducible data than the other measurements (intraclass test/retest correlation over 8 months, r = .83). SR scores were independent of standing height (r2 = .068) but were greater in women (p less than .002). The flexibility at all joints was less than reported for young adults. There were age-related decreases of flexibility scores for the head and shoulder joints (p less than .01), with a parallel trend (p less than .05) for ankle plantar flexion and SR scores (the last only after inclusion of an age-gender interaction term). A principal components analysis identified three factors (tentatively identified as general trunk, ankle, and shoulder flexibility) accounting for 55.9% of total variance. SR scores had a moderate correlation with the first factor (r = .61) but only weak correlations with the second and third. Although the SR test is the most reliable simple instrument, it provides only limited information about the flexibility at other joints in an older population.

This study measures the ground force patterns of 87 normal, older adults. It tests the hypothesis that there is a relation between a subject's mood as measured by the Beck Inventory, and the ground reaction forces as measured by a force plate during normal gait. Results showed that the push-off force in the posterior and downward directions was correlated with the expression of mood state. Lower mood individuals demonstrated a smaller push-off force and these ground force patterns of low mood state subjects resembled the patterns found in a previous study of clinically depressed patients. It is suggested that gait measurement could provide a sensitive index of level of depression in a clinical population.

The hydrolysis of inositol phospholipids appears to be an important aspect of cellular activation by a variety of neurotransmitters and hormones. We have investigated the role of this pathway in the metathoracic ganglion of the locust. After incubation with myo-[2-3H]inositol, ganglionic pieces incorporate label into lipid and water-soluble components. The latter can be separated on ion-exchange columns into five distinct peaks which are tentatively identified as; inositol, glycerophosphoinositol, inositol-1-phosphate, inositol-1,4-bisphosphate and inositol-1,4,5-trisphosphate. Although the levels of these hydrolysis products could not be influenced by exogenous neurotransmitters they were altered dramatically by both lithium and atropine. These results indicate the possible presence in the insect nervous system, of a class of muscarinic-like acetylcholine receptors that are linked to phosphatidylinositol metabolism.

Phenobarbital has been labeled with carbon-11 using no-carrier-added [11C]phosgene and diethyl carbonate in sodium ethoxide as the labeled intermediates. The synthesis is simpler than the former preparation using [11C]urea as the precursor and gives an improved yield of 35% in a slightly shorter time (30 min). The method is modeled on a similar synthesis previously reported, and serves to illustrate the general usefulness of diethyl carbonate aas a labeling intermediate.

In recent years the synthesis of 11C-labelled phosgene in this laboratory has undergone modifications which have improved the reliability and reproducibility of the method. In view of the growing usefulness of phosgene as a labelling precursor the details of the new procedure and a synthesis system with remote manipulation are reported.

Nine patients who had suffered strokes were examined between 10 and 34 days after onset using positron emission tomography. DMO labeled with carbon 11 was used to evaluate brain acid-base balance, and the oxygen-15 inhalation technique was used to measure regional cerebral blood flow, the oxygen extraction fraction, and cerebral metabolic rate for oxygen. [11C]DMO concentration and oxygen metabolism variables were measured in the infarcted area and in the symmetrical region in the contralateral cerebral hemisphere. [11C]DMO concentration was found to be unchanged or slightly increased in five cases and markedly increased in four cases. The apparent increase in tissue pH can be explained by the presence of a large extracellular fluid space with a pH nearly identical to that of brain plasma, or by an increase in intracellular pH, or by both phenomena. The change in [11C]DMO concentration in the infarcted area relative to that in the normal tissue was independent of the change in blood flow. Cerebral metabolic rate for oxygen was decreased in all cases. The increase in [11C]DMO concentration in the infarcted area was linearly correlated with the decrease in the oxygen extraction fraction in the same region; that is, it was correlated with the occurrence of perfusion in excess of metabolic demand. The overabundant local perfusion could play a role in the decreased H+ content.

AbstractA selective serotonin S2 receptor antagonist, ketanserin, was prepared labeled with carbon‐11 by a rapid synthesis which uses no‐carrier‐added phosgene as the labeled precursor. The ring‐closure reaction in toluene of phosgene with the substituted 2‐aminobenzamide precursor gives a nearly quantitative yield of ketanserin. The 30 min procedure yields 150 mCi of HPLC purified ketanserin at a specific activity of 250 mCi/μ mol. The product's tissue distribution in mice shows a brain uptake and cerebrum to cerebellum ratio that encourages further in vivo receptor binding studies.

No-carrier-added [2-11C]5, 5-dimethyloxazolidine-2, 4-dione (DMO) has been prepared rapidly and in good radiochemical yield. The synthesis involves in situ conversion of phosgene to diethyl carbonate which reacts with 2-hydroxy-2-methylpropionamide to yield labeled DMO. HPLC purification provided up to 1.85 GBq (50 mCi) of pure [11C]-DMO for injection. The product's in vivo distribution was examined in mice and rabbits. The results are encouraging for further application to in vivo measurement of intracellular pH using positron tomography.

The authors compared the gait patterns of 15 patients with affective disorders with those of 15 normal control subjects. The procedure involved a frame-by-frame analysis of a film of each subject walking at normal speed. Angle measurements were made of the hip and knee at their maximum extension during a single gait cycle (one stride). The results generally support the hypothesis that depressed patients walk with a lifting motion of the leg, whereas normal control subjects propel themselves forward.