Localization of allatostatin-immunoreactive material in the central nervous system, stomatogastric nervous system, and gut of the cockroach Blattella germanica

Immunoreactivity against peptides of the allatostatin family having a typical YXFGL-NH2 C-terminus has been localized in different areas of the central nervous system, stomatogastric nervous system and gut of the cockroach Blattella germanica. In the protocerebrum, the most characteristic immunoreactive perikarya are situated in the lateral and median neurosecretory cell groups. Immunoreactive median neurosecretory cells send their axons around the circumesophageal connectives to form arborizations in the anterior neuropil of the tritocerebrum. A group of cells in the lateral aspect of the tritocerebrum project to the antennal lobes in the deutocerebrum, where immunoreactive arborizations can be seen in the periphery of individual glomeruli. Nerve terminals were shown in the corpora allata. These terminals come from perikarya situated in the lateral neurosecretory cells in the pars lateralis and in the subesophageal ganglion. Immunoreactive axons from median neurosecretory cells and from cells positioned in the anteriormost part of the tritocerebrum enter together in the stomatogastric nervous system and innervate foregut and midgut, especially the crop and the valve between the crop and the midgut. The hindgut is innervated by neurons whose perikarya are located in the last abdominal ganglion. Besides immunoreactivity in neurons, allatostatin-immunoreactive material is present in endocrine cells distributed within the whole midgut epithelium. Possible functions for these peptides according to their localization are discussed.     

Identification of potent P2Y-purinoceptor agonists that are derivatives of adenosine 5'-monophosphate

1. A series of chain-extended 2-thioether derivatives of adenosine monophosphate were synthesized and tested as agonists for activation of the phospholipase C-linked P2Y-purinoceptor of turkey erythrocyte membranes, the adenylyl cyclase-linked P2Y-purinoceptor of C6 rat glioma cells, and the cloned human P2U-receptor stably expressed in 1321N1 human astrocytoma cells. 2. Although adenosine monophosphate itself was not an agonist in the two P2Y-purinoceptor test systems, eleven different 2-thioether-substituted adenosine monophosphate analogues were full agonists. The most potent of these agonists, 2-hexylthio AMP, exhibited an EC50 value of 0.2 nM for activation of the C6 cell receptor. This potency was 16,000 fold greater than that of ATP and was only 10 fold less than the potency of 2-hexylthio ATP in the same system. 2-hexylthio adenosine was inactive. 3. Monophosphate analogues that were the most potent activators of the C6 cell P2Y-purinoceptor were also the most potent activators of the turkey erythrocyte P2Y-purinoceptor. However, agonists were in general more potent at the C6 cell receptor, and potency differences varied between 10 fold and 300 fold between the two receptors. 4. Although 2-thioether derivatives of adenosine monophosphate were potent P2Y-purinoceptor agonists no effect of these analogues on the human P2U-purinoceptor were observed. 5. These results support the view that a single monophosphate is sufficient and necessary for full agonist activity at P2Y-purinoceptors, and provide insight for strategies for development of novel P2Y-purinoceptor agonists of high potency and selectivity.     

A PET study of the neural systems of stuttering

The cause of stuttering is unknown. Failure to develop left-hemispheric dominance for speech is a long-standing theory although others implicated the motor system more broadly, often postulating hyperactivity of the right (language nondominant) cerebral hemisphere. As knowledge of motor circuitry has advanced, theories of stuttering have become more anatomically specific, postulating hyperactivity of premotor cortex, either directly or through connectivity with the thalamus and basal ganglia. Alternative theories target the auditory and speech production systems. By contrasting stuttering with fluent speech using positron emission tomography combined with chorus reading to induce fluency, we found support for each of these hypotheses. Stuttering induced widespread overactivations of the motor system in both cerebrum and cerebellum, with right cerebral dominance. Stuttered reading lacked left-lateralized activations of the auditory system, which are thought to support the self-monitoring of speech, and selectively deactivated a frontal-temporal system implicated in speech production. Induced fluency decreased or eliminated the overactivity in most motor areas, and largely reversed the auditory-system underactivations and the deactivation of the speech production system. Thus stuttering is a disorder affecting the multiple neural systems used for speaking.     

The chemical anchoring of noble metal amine precursors to silica

The effect of pretreatment on the dispersion of supported noble metal Catalyst prepared from amine precursors in basic solution have been studied. The following metal precursors were used: Pt(NH₃)₄(NO₃)₂, Pd(NH₃)₄(NO₃)₂, Ru(NH₃)₆Cl₃ and [Rh(NH₃)₅Cl]Cl₂ Pretreatment in oxygen, prior to reduction in H₂ at 400C, resulted in poor dispersions for Ru and Rh, moderate dispersions for Pd and high dispersions for Pt. Pretreatment in H₂ resulted in poor dispersions for Pd and Pt and high dispersions for Ru and Rh. Decomposition of the adsorbed Pt and Pd precursors in argon resulted in very high dispersions.     

Use of a thick-film capillary column for the analysis of organic acids in body fluids

Contradictory evidence as to the effects of alcohol on early information processing stages has been obtained from behavioral and psychophysiological investigations. In the present study, choice reaction times, error rates, and event-related potentials (ERPs) were recorded in a task in which variations in stimulus discriminability and of the (task irrelevant) correspondence between stimulus location and response location were orthogonally combined. Both discriminability and stimulus-response correspondence affected reaction time and electrophysiological chronometric measures as expected. However, no behavioral effects of alcohol were observed, possibly because of strategic adjustments. Psychophysiological chronometric measures indicated that alcohol leaves the initial flow of perceptual evidence to motor stages unimpaired, whereas it appears to increase the duration of stimulus evaluation. Interestingly, a number of alcohol effects appeared in the ERP amplitudes. Decrements in early ERP components indicate alcohol-induced impairments of involuntary visual attention and/or the automatic stimulus location-dependent activation of response channels. In contrast, a strong enhancement of a late slow-wave component under alcohol may reflect the investment of processing resources in order to maintain normal performance levels.     

Microbiological results from milk samples obtained premilking and postmilking for the diagnosis of bovine intramammary infections.

Bacteriological culture results were compared between 336 pairs of quarter milk samples collected premilking and postmilking. Using a positive result on either premilking or postmilking samples as the definitive diagnosis, premilking sampling sensitivity was 91% for Staphylococcus aureus, 91% for coagulase-negative staphylococci, and 97% for Streptococcus other than agalactiae. Postmilking sampling sensitivities were 81, 45, and 58%, respectively, for the same pathogens. Requiring both premilking and postmilking samples for the definitive diagnosis, specificities were 92, 86, and 95% for premilking sampling alone and 96, 98, and 99% for postmilking sampling alone. Such differences in specificity would result in major differences in predictive value of a positive culture for herds with a low prevalence. Multiple isolates were significantly more common from premilking samples.     

Shumbler: a 155 Mb/s BiCMOS synchronous multiplexer chip for abroad-band customer premises network

The shumbler (shuffler/scrambler) is a circuit designed and fabricated to form part of a broadband customer premises network. The circuit is implemented in 1.2-μm BiCMOS double-metal technology. The circuit is bidirectional, and can perform the functions of scrambling and shuffling or descrambling and unshuffling by means of control signals to three integrated multiplexers. The shumbler also includes a programmable multiplexer that allows the selection of one out of the 16 output channels of the shuffler through a serial output for local system test purposes. The shumbler circuit interfaces emitter-coupled-logic (ECL) and transistor-transistor-logic (TTL) logic levels using a single power supply of -5 V, dissipating 1.5 W, and encapsulated in a 68-pin LCC package with a flat heat spreader which ensures a thermal resistivity of about 10°C/W