Incidentally Detected 18F-PSMA Uptake in Glomus Jugulare.

PSMA (prostate-specific membrane antigen) PET/CT scan is the imaging modality of choice for staging and restaging of carcinoma prostate. Although initially thought to be a tracer with high specificity for prostatic tissue, with its extensive clinical use, there has been a rise in published literature citing its uptake in nonprostatic conditions. We present a case where false-positive PSMA uptake was noted in glomus jugulare during staging workup for carcinoma prostate.

[Global systems for monitoring cerebral hemodynamics in the neurocritical patient: basic concepts, controversies and recent advances in measuring jugular bulb oxygenation]. / Métodos globales de monitorización de la hemodinámica cerebral en el paciente neuricrítico: fundamentos, controversias y actualizaciones en las técnicas de oximetría yugular

Because of the importance of hypoxic/ischemic phenomena in head-injured patients, brain monitoring in these patients should be complemented by systems providing information on cerebral blood flow and metabolism. Indirect estimations of cerebral blood flow have been obtained from blood extracted from the jugular bulb, as a special bedside application of the Fick's principle to the brain. In the last few years, the use of jugular oximetry techniques has become routine in centers treating head-injured and other neurocritical patients such as those presenting subarachnoid hemorrhage or malignant middle cerebral artery infarction. The experience acquired in the use of these techniques, as well as the introduction of new neuromonitoring systems, have deepened our understanding of the information gained and have enabled more precise definition of their indications and limitations. This review describes the basic concepts underlying the use of jugular oximetry techniques in the neurocritical patient. We also explain the reasons why several variables derived from jugular blood such as arterio-jugular differences of lactate (AVDL) or the lactate-oxygen index (LOI) do not provide accurate information on brain metabolism.

Effect of olvanil and anandamide on vagal C-fiber subtypes in guinea pig lung.

Certain fatty acid amides such as anandamide (AEA) and olvanil are agonists for the transient receptor potential, vanilloid-1 (TRPV1) receptor, but have been found to activate TRPV1-containing C-fibers in some tissues but not others. We used extracellular recording and whole-cell patch clamp techniques to investigate the effect of olvanil and AEA on different types of vagal C-fibers innervating the same tissue, namely jugular and nodose vagal C-fibers in guinea pig lungs. A 30 s exposure to AEA and olvanil caused action potential discharge in all nodose C-fiber innervating lung but failed to activate jugular C-fibers innervating lung and airways. The activation of nodose C-fibers was blocked by the TRPV1 antagonist iodo-resiniferatoxin. In whole-cell patch clamp recordings of dissociated nodose and jugular capsaicin-sensitive neurons labeled from lungs and airways, olvanil induced large TRPV1-dependent inward currents in cell bodies of both nodose and jugular ganglion neurons. Prolonged exposure (up to 5 min) to olvanil caused action potential discharge in jugular C-fiber innervating lung but the onset latency was four times longer in jugular than in nodose C-fibers. The onsets of capsaicin response in nodose and jugular C-fibers were not different. Decreasing the tissue temperature to 25 degrees C increased the onset latency of olvanil-induced activation of nodose C-fibers 2-3-fold, but did not effect the latency of the capsaicin response. Capsaicin, olvanil, and AEA stimulate jugular C-fibers leading to tachykinergic contractions of isolated bronchi. The time to reach half-maximum is more than four times longer for olvanil and AEA, as compared to capsaicin in evoking contractions. We conclude that brief exposure to certain fatty acid amides, such as AEA and olvanil activate nodose but not jugular C-fiber terminals in the lungs. We hypothesize that this is because the nodose C-fiber terminals are equipped with a temperature-dependent mechanism for effectively and rapidly transporting the TRPV1 agonists so that they gain access to the intracellular binding sites on TRPV1. This transport mechanism may be differently expressed in two distinct subtypes of pulmonary C-fiber terminals innervating the same tissue.

Métodos globales de monitorización de la hemodinámica cerebral en el paciente neurocrítico: fundamentos, controversias y actualizaciones en las técnicas de oximetría yugular / Global systems for monitoring cerebral hemodynamics in the neurocritical patient: basic concepts, controversies and recent advances in measuring jugular bulb oxygenation

El papel relevante que la hipoxia tisular cerebral juega en la fisiopatología de los pacientes con un traumatismo craneoencefálico (TCE) justifica la necesidad de complementar la monitorización de estos pacientes con sistemas que aporten información sobre el flujo sanguíneo y el metabolismo cerebral. En la búsqueda de sistemas útiles en la cabecera del paciente, se han utilizado extrapolaciones del principio de Fick al encéfalo, utilizando métodos que estiman el flujo sanguíneo cerebral (FSC) a partir de la obtención de muestras de sangre del bulbo de la yugular. En los últimos años, las técnicas de oximetría yugular se han convertido en elementos de uso frecuente en las unidades que tratan pacientes con un TCE u otros pacientes neurocríticos, como los pacientes con una hemorragia subaracnoidea o con infartos masivos de la arteria cerebral media. El uso frecuente de estas técnicas en las últimas dos décadas, junto a la incorporación de otros sistemas de neuromonitorización, permiten en la actualidad matizar la información que estos métodos globales proporcionan y definir mejor tanto sus indicaciones como sus limitaciones. El objetivo de esta revisión es presentar los fundamentos y los conceptos básicos relacionados con la utilización clínica de las técnicas de oximetría yugular en el paciente neurocrítico. También presentamos y discutimos la evidencia más reciente que indica que determinadas variables, obtenidas de muestras de sangre del bulbo de la yugular, tales como las diferencias arterio-yugulares de lactatos (AVDL) y el índice lactato-oxígeno (LOI), a pesar de su amplia utilización en la práctica clínica diaria, no ofrecen una información fiable sobre el metabolismo cerebral que permita la toma de decisiones terapéuticas

Because of the importance of hypoxic/ischemic phenomena in head-injured patients, brain monitoring in these patients should be complemented by systems providing information on cerebral blood flow and metabolism.Indirect estimations of cerebral blood flow have been obtained from blood extracted from the jugular bulb, as a special bedside application of the Fick’s principle to the brain. In the last few years, the use of jugular oximetry techniques has become routine in centers treating head-injured and other neurocritical patients such as those presenting subarachnoid hemorrhage or malignant middle cerebral artery infarction. The experience acquired in the use of these techniques, as well as the introduction of new neuromonitoring systems, have deepened our understanding of the information gained and have enabled more precise definition of their indications and limitations. This review describes the basic concepts underlying the use of jugular oximetry techniques in the neurocritical patient. We also explain the reasons why several variables derived from jugular blood such as arterio-jugular differences of lactate (AVDL) or the lactate-oxygen index (LOI) do not provide accurate information on brain metabolism

Normal jugular bulb oxygen saturation.

BACKGROUND: Normal values of the jugular bulb oxygen saturation were obtained in 1942 and in 1963. Correct catheter positioning was not confirmed radiologically. OBJECTIVES: To replicate the measurements during angiographic catheterisation of the jugular bulb. METHODS: Oxygen saturation in the jugular bulb (SjO(2)), inferior petrosal sinus (SipsO(2)), and internal jugular vein was bilaterally measured in 12 patients with Cushing's syndrome undergoing selective bilateral catheterisation of the inferior petrosal sinus. In addition, data from the two old series were reanalysed for comparison. RESULTS: SjO(2) values (44.7%) were significantly lower than in the two old series, particularly concerning the normal lower limit (54.6% and 55.0% respectively). Comparative analysis suggests that contamination with the extracerebral blood of the facial veins and inferior petrosal sinuses was responsible for falsely high SjO(2) values in the two old series. CONCLUSIONS: The normal lower SjO(2) limit is lower than previously recognised. This may have practical implications for treating severe head trauma patients.

Comparison of capsaicin-evoked calcium transients between rat nodose and jugular ganglion neurons.

The objectives of this study were to describe the size distribution of capsaicin-sensitive neurons in nodose and jugular ganglia and to determine whether there is a difference in capsaicin sensitivity between these two types of ganglia. Functional identification was made by measurement of the capsaicin-evoked calcium (Ca2+) transients in cultured vagal sensory neurons of young adult Sprague-Dawley rats using the Fura-2-based ratiometric imaging technique. In the first study series, cells on the second day of culture were perfused with capsaicin solution (10(-7) M) for 15 s, and the Ca2+ transients were continuously recorded before, during, and after the capsaicin challenge. Out of 603 viable neurons, 57.5% were capsaicin-sensitive; the percentages of capsaicin-sensitive cells in the nodose and jugular ganglia were 59.8% and 55.4%, respectively. Capsaicin sensitivity predominated in the small- and medium-sized neurons; the capsaicin-sensitive cells generally had a diameter less than 35 microm in both types of ganglia. Although the results did not indicate any differences in the size distribution of capsaicin-sensitive neurons between the two ganglia, results of our second study series showed that a near-maximal concentration of capsaicin (3 x 10(-6) M) evoked a significantly greater peak Ca2+ transient in jugular neurons (382.5 +/- 85.5 nM) than in nodose neurons (134.3 +/- 17.5 nM). In summary, our results showed that an increase in cell diameter was accompanied by a decreasing trend in percentage of capsaicin-sensitive neurons in both vagal ganglia. Capsaicin at high concentration evoked a greater peak Ca2+ transient in jugular ganglion neurons, despite no difference in the responses to KCl between these two types of ganglion neurons.

Presence of reciprocal synapses in the rabbit carotid body.

The synaptic junctions between glomus cells and nerve endings in the rabbit carotid body were studied by electron microscopy. Many of them were morphologically of afferent type, glomus cells being presynaptic to nerve endings; occurrence of efferent synapses was less common than that of afferent synapses. In addition, reciprocal synapses in which two or more junctions of opposite polarity were lying side by side were frequently seen particularly between large nerve endings and glomus cells. Some single synapses were discovered to be part of reciprocal synapses through examination of serial sections. The results support possible participation of dopamine in a modulatory feedback loop through reciprocal synapses in the rabbit carotid body.