Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0220723 (PCA)
 4,687 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Significantly higher levels of uric acid in serum and urine together with increased urine volume and pH were observed in rats after portacaval end-to-side anastomosis in comparison to sham-operated and non-operated pair-fed controls. An increased supply of endogenous uric acid by reduced transformation of uric acid to allantoin and decreased uricase activity in the liver was assumed. Adaptation of enzyme activities of other metabolic pathways of the liver after PCA due to diminished blood and oxygen supply were described in previous experiments. This model seems suitable for other studies on hyperuricemia, hyperuricosuria and uric acid lithiasis.
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PMID:[Changes of serum and urinary uric-acid levels after portacaval anastomosis in the rat]. 2 97

The literature on the toxicity of aminoxyl radicals was critically reviewed. It was concluded that, in general, the aminoxyl radicals possess a very low toxicity and are not mutagenic. In support of this contention, several aminoxyl radicals were evaluated in vitro. Thus, aminoxyl radicals 3-carboxy-2,2,5,5-tetramethylpyrroline-1-oxyl (1), 3-carboxy-2,2,5,5-tetramethylpyrrolidine-1-oxyl (PCA; 2), 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl (Tempol;3), and N-(1-hydroxymethyl-2,3-dihydroxypropyl)-3-carboxyamino-2,2,5,5- tetramethylpyrrolidine-1-oxyl (NAT; 4) were evaluated using Salmonella typhimurium tester strains TA 102 and TA 104, with a supplement of xanthine oxidase enzyme. 1, 2, and 4 were found to be nonmutagenic, while 3 elicited in TA 104 only about a twofold increase in the number of revertants above the control. This response is considered to be, at best, marginal in view of wide fluctuations of experimental scores. The results of the present study are in agreement with those of other studies confirming the nonmutagenicity of aminoxyl radicals investigated to date. However, these conclusions are different from those of a study where 3 was tested in the presence of a generated toxic oxygen species that can cause mutagenic changes of the environment.
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PMID:A critical evaluation of the present status of toxicity of aminoxyl radicals. 152 84

Previous data from model systems indicated that the proxyl nitroxides should be especially resistant to bioreduction and therefore could be an effective solution to this often problematic characteristic of nitroxides. Therefore, we investigated the rate of reduction by cells and by the usual model system, ascorbate, of four proxyl nitroxides and three reference nitroxides. We found that, while the rate of reduction by ascorbate of the proxyl nitroxides was slower than the rate of a prototypic pyrrolidine nitroxide (PCA), the reverse was true for reduction by cells. We also studied the rate of oxidation of the corresponding hydroxylamines. The rate of oxidation by cells of the proxyl hydroxylamines was relatively fast, especially for the most lipophilic derivative. These results indicate that: (i) proxyl nitroxides may not be unusually resistant to bioreduction by functional biological systems; (ii) accurate knowledge of relative rates of metabolism of nitroxides and hydroxylamines in cells and tissues will require direct studies in these systems because the rates may not closely parallel those observed in model (chemical) systems; and (iii) proxyl nitroxides show potential value as agents to measure oxygen concentrations by the rates of oxidation of their corresponding hydroxylamines.
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PMID:Cellular metabolism of proxyl nitroxides and hydroxylamines. 184 7

Even though the PET study revealed a total infarct in the territory of the left PCA in our 3 cases of pure alexia, it is still obscure which part of the left occipital lobe is most closely associated with the occurrence of the pure alexia. In order to elucidate the intralobar localization of the pure alexia, it is needed to have an ideal case who shows an pure alexia due to the localized lesion within the left occipital lobe. Furthermore, high-resolution PET scanner will circumvent the problem in detecting the metabolism and blood flow in the corpus callosum which plays an important role in the pathogenesis. We have shown that the occlusion of the right PCA also produced a left unilateral agnosia which is one of the common neurological signs in the right MCA infarction. To tell whether the responsible lesion for the unilateral spatial agnosia differs between the PCA occlusion and the MCA occlusion, the correlation study should be carried out in a greater number of the subjects. Two distinctive neuropsychological manifestations, cerebral color blindness and prosopagnosia, have been considered to be produced by the bilateral occipital lesion. The PET studies disclosed reduction of blood flow and oxygen metabolism in both occipital lobes in our particular patient who exhibited cerebral color blindness and prosopagnosia.
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PMID:Occipital lobe infarction and positron emission tomography. 208 96

The in vivo uptake distribution and reduction of the oxygen-sensitive nitroxide spin label PCA in the mouse monitored by low frequency electron paramagnetic resonance (EPR) spectroscopy are reported. Spectra were obtained from the head and liver regions of pentobarbital anesthetized mice during different circulatory and ventilatory conditions. Identical clearances were found in these regions during normoxia. Moderate hypoxia (10% O2-90% N2) did not significantly affect the spin label reduction rate.
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PMID:Whole mouse nitroxide free radical pharmacokinetics by low frequency electron paramagnetic resonance. 215 98

Direct measurements of local oxygen pressure by means of platinum multiwire electrode were performed in rats to investigate the effect of an end-to-side portocaval shunt procedure on muscle tissue oxygenation. Compared with intact rats and/or sham operated animals, rats with portocaval anastomosis showed a significant increase of muscle tissue oxygenation with nearly bellshaped pO2 histograms. This considerable increase in tissue oxygenation might appear to be due to the well known PCA induced hyperdynamic cardiovascular state.
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PMID:Measurements of local PO2 in the resting skeletal muscles of rats with portocaval anastomosis (PCA) under normoxic conditions. 653 34

A dissimilatory metal- and sulfur-reducing microorganism was isolated from surface sediments of a hydrocarbon-contaminated ditch in Norman, Okla. The isolate, which was designated strain PCA, was an obligately anaerobic, nonfermentative nonmotile, gram-negative rod. PCA grew in a defined medium with acetate as an electron donor and ferric PPi, ferric oxyhydroxide, ferric citrate, elemental sulfur, Co(III)-EDTA, fumarate, or malate as the sole electron acceptor. PCA also coupled the oxidation of hydrogen to the reduction of Fe(III) but did not reduce Fe(III) with sulfur, glucose, lactate, fumarate, propionate, butyrate, isobutyrate, isovalerate, succinate, yeast extract, phenol, benzoate, ethanol, propanol, or butanol as an electron donor. PCA did not reduce oxygen, Mn(IV), U(VI), nitrate, sulfate, sulfite, or thiosulfate with acetate as the electron donor. Cell suspensions of PCA exhibited dithionite-reduced minus air-oxidized difference spectra which were characteristic of c-type cytochromes. Phylogenetic analysis of the 16S rRNA sequence placed PCA in the delta subgroup of the proteobacteria. Its closest known relative is Geobacter metallireducens. The ability to utilize either hydrogen or acetate as the sole electron donor for Fe(III) reduction makes strain PCA a unique addition to the relatively small group of respiratory metal-reducing microorganisms available in pure culture. A new species name, Geobacter sulfurreducens, is proposed.
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PMID:Geobacter sulfurreducens sp. nov., a hydrogen- and acetate-oxidizing dissimilatory metal-reducing microorganism. 752 4

The photostability and phototoxic potential of two new 4-alkyl-1,4-dihydropyridines (PCA-4230 and PCA-4248) were investigated. When these 4-alkyl-1,4-dihydropyridines were irradiated with a multilamp photoreactor (band centred at 350 nm), both exhibited a slow photodegradation showing first-order kinetics. The photodegradation rate constants were 0.37 h-1 for PCA-4248 and 0.39 h-1 for PCA-4230 in oxygenated conditions. The photodecomposition was slower for both drugs in the absence of oxygen. In order to evaluate the phototoxicity induced by these drugs, red blood cells and Hep-2 (human laringo carcinoma cell line) were irradiated using a minisolarium, which emits UVA radiation (350-390 nm). The results showed that PCA-4248 and PCA-4230 did not exhibit a phototoxic effect in the two models tested.
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PMID:New 4-alkyl-1,4-dihydropyridines: evaluation of photostability and phototoxic potential. 837 76

Efficacy and safety of a PCA protocol, without loading dose or background infusion, was investigated in 40 consenting patients after osteotomy of the foot. All patients had intrathecal lidocaine 5% 1.8 ml preoperatively. Postoperative pain relief was provided with morphine from a Baxter Travenol infusor with PC module. The morphine concentration was 2 mg/ml or 3 mg/ml. In order to reach the analgesic blood concentration as quickly as possible, the patients were instructed to start PCA from the very first moment pain occurred. The patients breathed room air. The nursing staff evaluated respiratory and cardiovascular parameters, pain and side effects. Although mean VAS scores were higher than 3 in the early postoperative phase, no supplementary analgesics were required. One patient had urine retention. One patient had a drop in blood pressure at the start of morphine, which was quickly restored with the administration of colloids. Oxygen saturations were lower (SpO2 < 95%) the first hours postoperatively, especially at the first assessment where no morphine was administered. Pain or relative hypovolaemia could be an explanation. Dry mouth and sleepiness were the most frequently reported side-effects, followed by dizziness, vomiting and nausea. Sweating and itching were less frequently reported. The occurrence of the side effects was the highest during the first postoperative day. We conclude that even when morphine is used in PCA without loading dose or background infusion after opiate-free locoregional analgesia, close monitoring is necessary for at least 5 hours.
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PMID:Evaluation of morphine for patient controlled analgesia with the Infusor system after opiate-free locoregional anesthesia for osteotomy of the foot. 866 16

Recovery characteristics, haemodynamic profile, analgesic requirement and costs were evaluated and compared in patients undergoing elective lumbar discectomy with remifentanil-based anaesthesia using either desflurane or sevoflurane as the volatile anaesthetic agent. Sixty-two patients (ASA I/II status) were randomly assigned to receive either desflurane and remifentanil or sevoflurane and remifentanil (in oxygen/air) for anaesthesia. After induction with 0.5 microgram/kg/min remifentanil, 4 to 5 mg/kg thiopentone and 0.5 mg/kg atracurium, the patients received 0.25 microgram/kg/min remifentanil and 0.5 +/- 0.05 MAC of one of the volatile anaesthetic agents for further maintenance of anaesthesia. At the end of surgery, early emergence from anaesthesia was recorded by assessing the time to sufficient spontaneous respiration, eye opening and tracheal extubation. The total demand of piritramide in the postoperative period was determined using patient-controlled analgesia (PCA device). Quality of pain therapy was assessed via a verbal ranking scale (VRS). Side-effects such as postoperative nausea, vomiting or shivering were recorded in the postanaesthetic care unit. In both groups, the haemodynamic profile was nearly identical. Mean arterial pressure (-18%) and heart rate (-23%) were significantly reduced throughout anaesthesia in both groups. All recovery parameters were significantly shorter in the desflurane group in comparison with the sevoflurane group (e.g. time to tracheal extubation: 8.5 +/- 3.0 min vs. 11.9 +/- 4.6 min). No significant differences between the groups were observed concerning the amount of piritramide required, side-effects such as nausea and vomiting or the total cost of anaesthesia. In conclusion, both anaesthetic techniques provide adequate haemodynamic stability and postoperative pain control in a surgical procedure with minimal trauma. Incidence and severity of side-effects such as nausea, vomiting or shivering did not differ between the groups and were acceptable under clinical conditions. Costs for desflurane were significantly higher than those for sevoflurane, but total costs were not different between the groups. Concerning recovery profile, desflurane/remifentanil seems to have small advantages over sevoflurane/remifentanil in patients undergoing lumbar vertebral disc resection.
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PMID:[Anesthesia with remifentanil combined with desflurane or sevoflurane in lumbar intervertebral disk operations]. 1119 83


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