Modulation of exteroceptive suppression periods in human jaw-closing muscles by subanaesthetic dose of propofol.

Exteroceptive suppression (ES) periods in human jaw-closing muscles can be conditioned by a wide range of somatosensory stimuli and cognitive states. The aim of this study was to examine the effects of subanaesthetic doses of midazolam, ketamine and propofol on the short latency (ES1) and long latency (ES2) reflex in the jaw-closing muscles. First, we tried to evaluate the various methodological criteria for ES recording. We then examined the effect of subanaesthetic doses of midazolam (0·035 mg kg(-1)), ketamine (0·30 mg kg(-1)) and propofol (0·35 mg kg(-1)) on these reflexes of recording left masseter and temporalis muscle. ES duration did not differ greatly in the present study, recorded with the correct adjustment of stimulating and recording conditions. None of the subanaesthetic doses of the agents influenced ES1, and no significant effects on ES2 were observed with midazolam and ketamine. However, significant inhibitory change was observed in ES2 with propofol. ES2 is thought to be mediated by afferents, which descend in the spinal trigeminal tract and connect with a polysynaptic chain of excitatory interneurones located in the lateral reticular formation. Our observations indicate that propofol is uniquely effective not only through involvement of the gamma-aminobutyric acid type A receptor, but also through a range of other effects.

Effects of functional training of dysphagia to prevent pneumonia for patients on tube feeding.

OBJECTIVE: The purpose of this study was to evaluate the effects of functional training on outbreak frequency of pneumonia for the elderly dysphagia patients who were being tube fed. METHODS: Subjects were divided into two groups; one group (n = 10) received oral care (i.e. non-training group) and the other group (n = 11) received functional training of dysphagia in addition to oral care (i.e. training group). The dental health team treated subjects once a week for 3 years (1999-2001). The frequency of pneumonia outbreaks and changes in activities of daily living scale (ADL) were evaluated for each year. RESULT: It was recognised that the frequency of pneumonia in the training group decreased year by year (p < 0.05). Cognitive items in ADL improved in two subjects of the training group. No statistical differences were recognised in the non-training group. CONCLUSION: It was suggested that once-a-week functional training of dysphagia with professional oral care might be effective in preventing pneumonia for elderly people who were being tube fed.

Sevoflurane and isoflurane reduce oxygen saturation in infants.

Volatile anesthetics are generally known to exert several influences on the respiratory system, but their direct effect on oxygen saturation as measured by pulse oximetry (SpO2) in infants remains unknown. In this study, 70 infants under 2 years of age who received general anesthesia were examined to determine the effects of several volatile anesthetics and nitrous oxide on SpO2. After endotracheal intubation, the subjects were ventilated using a Jackson-Rees circuit with oxygen, nitrous oxide, and either sevoflurane, enflurane, or isoflurane adjusted to twice the adult minimum alveolar concentration (MAC) for the agents when used in combination with 67% nitrous oxide. In all cases, the end-tidal carbon dioxide tension (PetCO2) was maintained within the same range (28-35 mm Hg). Significantly lower SpO2 values (paired t test, P < .05) were observed when the subjects were ventilated with oxygen, 67% nitrous oxide, and sevoflurane or isoflurane--but not with oxygen, 67% nitrous oxide, and enflurane--than when they were administered oxygen, 50% nitrous oxide, and the original concentration of each volatile anesthetic. These results suggest that sevoflurane and isoflurane have different effects from enflurane on gas exchange systems.

Stimulation of plasma membrane Ca2+ -pump ATPase of vascular smooth muscle by cGMP-dependent protein kinase: functional reconstitution with purified proteins.

A 240-kDa protein isolated from porcine aortic smooth muscle as a substrate for cGMP-dependent protein kinase (cGMP kinase) whose phosphorylation was in a close association with stimulation of partially purified plasma membrane Ca2+ -pump ATPase by the kinase was later shown to represent splicing variants of type 1 inositol 1,4,5-trisphosphate (IP3) receptor. To further clarify the role played by this protein in the stimulation of Ca2+ -pumpATPase, it was attempted in thepresent study to specifically remove the protein by immunoprecipitation with an antibody specific to type 1 IP3 receptor. Contrary to expectation, stimulation of the ATPase by cGMP kinase was still observed after removal of the IP3 receptor. Furthermore, cGMP kinase stimulated a highly purified preparation of Ca2+ -pump ATPase deprived of IP3 receptor when the concentrations of the ATPase were low enough (10-20 nM) to make it retain a monomeric form, while it did not produce stimulation when the concentration of the enzyme was increased to 40 nM at which the enzyme is known to take an oligomeric, fully activated form insensitive to activation by calmodulin. Heat-inactivated cGMP kinase and cGMP kinase without cGMP failed to stimulate the highly purified Ca2+ -pumpATPase. In addition, type Ialpha but not type Ibeta cGMP kinase was found to stimulate the ATPase. The stimulation of Ca2+ -pump ATPase by cGMP kinase occurs without any detectable phosphorylation of the ATPase. In conclusion, cGMP kinase can stimulate the plasma membrane Ca2+ -pump ATPase when it is in a monomeric form without phosphorylating the Ca2+ -pump ATPase and that of the two cGMP kinase isozymes found in the vascular smooth muscle, only type Ialpha cGMP kinase participates in the stimulation.

cGMP-kinase mediates cGMP- and cAMP-induced Ca2+ desensitization of skinned rat artery.

(Rp)-8-Bromo-guanosine 3',5'-cyclic monophosphorothioate (Rp-8-Br-cGMPS) inhibited competitively both isozymes of type I alpha and I beta cGMP-dependent protein kinase (cGMP-kinase) purified from porcine aorta with apparent Ki values (microM) of 3.7 for I alpha and 1.8 for I beta. The compound also inhibited bovine heart type II cAMP-dependent protein kinase (cAMP-kinase), but with a Ki of 25 microM. Thus, it is a selective inhibitor of cGMP-kinase. In alpha-toxin-skinned smooth muscle preparations from rat mesenteric artery, 8-Br-cGMP (10(-7) M) and 8-Br-cAMP (10(-6) M) produced a rightward shift of the concentration-contraction curves for Ca2+, denoting a decrease in Ca2+ sensitivity of the contractile elements. The shift by 8-Br-cAMP as well as by 8-Br-cGMP was completely reversed by Rp-8-Br-cGMPS, while a selective inhibitor of activation of cAMP-kinase, (Rp)-adenosine-3',5'-cyclic monophosphorothioate (Rp-cAMPS), was without effects on the shift produced by these two compounds. These findings indicate the pivotal role that the activation of cGMP-kinase plays in the production of a decrease in Ca2+ sensitivity of contractile elements.

[Diagnostic value of duodenal drainage in patients with biliary symptoms and negative imaging test]. / Valor diagnóstico del sondaje duodenal en pacientes con clínica biliar y test de imagen negativo.

A group of patients with clinical manifestations suggesting biliary origin in whom diagnostic imaging techniques were negative were studied by duodenal biliary drainage with the aim of identifying whether microcalculi were present in the bilis being responsible for the symptomatology. The problem group was made up of 96 patients with the results being compared with those of a control group (without biliary disease) including 45 subjects. Duodenal biliary drainage was analyzed for the detection of microlithiasis in the biliary sediment in all the subjects. The analysis was positive in 46 (47.9%) of the patients with biliary clinical manifestations while analysis was positive in only 5 (11.2%) of the control group with the differences being statistically significant. Seventeen of the 46 positive patients underwent surgery demonstrating biliary disease in all (chronic cholecystitis). All these patients remained asymptomatic except one on follow up with 94.1% cure by cholecystectomy being achieved. The authors conclude that duodenal biliary drainage is a highly profitable, complication-free and easily performed diagnostic technique for the detection of microlithiasis which should be regularly used in patients with symptoms suggestive of biliary origin and complementary negative explorations.