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Continuous Intravenous Infusion (continuous + intravenous_infusion)
Selected AbstractsThe Effect of Progesterone on Coronary Blood Flow in Anaesthetized PigsEXPERIMENTAL PHYSIOLOGY, Issue 1 2001C. Molinari The present study was designed to investigate the effect of progesterone on the coronary circulation and to determine the mechanisms involved. In pigs anaesthetized with sodium pentobarbitone, changes in left circumflex or anterior descending coronary blood flow caused by intravenous infusion of progesterone at constant heart rate and arterial blood pressure were assessed using an electromagnetic flowmeter. In 14 pigs, infusion of 1 mg h,1 of progesterone caused an increase in coronary blood flow without affecting left ventricular dP/dtmax (rate of change of left ventricular systolic pressure) and filling pressures of the heart. In a further four pigs, this vasodilatory coronary effect was enhanced by graded increases in the dose of the hormone of between 1, 2 and 3 mg h,1. The mechanisms of the above response were studied in the 14 pigs by repeating the experiment after haemodynamic variables had returned to the control values observed before infusion. In six pigs, blockade of muscarinic cholinoceptors and adrenoceptors with atropine, propranolol and phentolamine did not affect the coronary vasodilatation caused by progesterone. In the remaining eight pigs, this response was abolished by intracoronary injection of N, -nitro-L-arginine methyl ester (L-NAME) even when performed after reversing the increase in arterial blood pressure and coronary vascular resistance caused by L-NAME with continuous intravenous infusion of papaverine. The present study showed that intravenous infusion of progesterone primarily caused coronary vasodilatation. The mechanism of this response was shown to involve the endothelial release of nitric oxide. [source] Correlation between serum concentrations following continuous intravenous infusion of dexmedetomidine or medetomidine in cats and their sedative and analgesic effectsJOURNAL OF VETERINARY PHARMACOLOGY & THERAPEUTICS, Issue 1 2000Ansah Dexmedetomidine (DEX) may have some therapeutic advantages over the racemate medetomidine (MED). Here we have examined how serum concentrations of DEX correlate with some of its anaesthetic effects. Cats (n = 6) were administered with a continuous stepwise intravenous (i.v.) infusion of DEX or MED on different occasions in a cross-over design. Maintenance infusion rates (mg/kg/min) used were: DEX = 0.25 (MED = 0.50); DEX = 1 (MED = 2) and DEX = 4 (MED = 8) for infusion steps 1, 2 and 3, respectively. Each maintenance infusion lasted at least 50 min and was preceded with a loading dose. There was no significant difference between serum DEX and 0.5 serum MED concentrations at any dose level nor was there a significant difference between serum DEX and the (entire) serum MED concentrations. There was no significant difference between DEX and MED for sedation, analgesia, muscular relaxation and heart and respiratory rates. For both DEX and MED, serum drug concentration and analgesia were dose-dependent and sedation increased until the end of infusion step 2 (dose level 2) and decreased at the end of step 3 (dose level 3). Muscular relaxation was not dose-dependent. We conclude that increasing the blood concentration of DEX or MED beyond a certain level decreases the level of sedation instead of increasing it even though analgesia increases. The rate at which DEX and MED are metabolized in cats may not be the same. [source] Phase I study of paclitaxel with standard dose ifosfamide in children with refractory solid tumors: A Pediatric Oncology Group study (POG 9376)PEDIATRIC BLOOD & CANCER, Issue 3 2009James I. Geller MD Abstract Purpose A dose-escalation Phase I study of taxol (paclitaxel) administered in combination with standard dose ifosfamide was conducted in children with relapsed or refractory solid tumors. Primary objectives were to estimate the maximum tolerated dose (MTD) and to describe the dose-limiting toxicities (DLTs). Patients and Methods Paclitaxel was administered as a 6-hr continuous infusion (hr 0,6), followed by intravenous ifosfamide (2 g/m2/day,×,3 days) over 1 hr at hours 6,7, 24,25, and 48,49. Patients at dose level 1 received 250 mg/m2 paclitaxel. Subsequent dose escalation proceeded using a standard 3,×,3 Phase I design. Results Fifteen patients received a combined 46 courses of therapy. The median age was 14.5 years (range, 2,19 years), and diagnoses included sarcoma (7), neuroblastoma (3), and other (5). Three patients received paclitaxel at 250 mg/m2 (10 courses), six at 325 mg/m2 (19 courses), three at 425 mg/m2 (8 courses), and three at 550 mg/m2 (9 courses). DLTs occurred in 2/3 patients at 550 mg/m2 paclitaxel during cycle 1, including grade 3 hypotension and grade 4 anaphylaxis in 1 patient each. Common non-dose-limiting toxicities included bone marrow suppression and peripheral neuropathy. Response was evaluable in 14 patients and included mixed response (3), stable disease (5), and progressive disease (6). Conclusion Paclitaxel hypersensitivity reactions were dose limiting when the drug was administered as a 6-hr infusion. The MTD and recommended Phase II dose of paclitaxel administered as a 6-hr continuous intravenous infusion followed by standard dose intravenous ifosfamide is 425 mg/m2 paclitaxel. Pediatr Blood Cancer 2009;52:346,350. © 2008 Wiley-Liss, Inc. [source] Intestinal and hepatic metabolism of glutamine and citrulline in humansTHE JOURNAL OF PHYSIOLOGY, Issue 2 2007Marcel C. G. Van De Poll Glutamine plays an important role in nitrogen homeostasis and intestinal substrate supply. It has been suggested that glutamine is a precursor for arginine through an intestinal,renal pathway involving inter-organ transport of citrulline. The importance of intestinal glutamine metabolism for endogenous arginine synthesis in humans, however, has remained unaddressed. The aim of this study was to investigate the intestinal conversion of glutamine to citrulline and the effect of the liver on splanchnic citrulline metabolism in humans. Eight patients undergoing upper gastrointestinal surgery received a primed continuous intravenous infusion of [2- 15N]glutamine and [ureido- 13C,2H2]citrulline. Arterial, portal venous and hepatic venous blood were sampled and portal and hepatic blood flows were measured. Organ specific amino acid uptake (disposal), production and net balance, as well as whole body rates of plasma appearance were calculated according to established methods. The intestines consumed glutamine at a rate that was dependent on glutamine supply. Approximately 13% of glutamine taken up by the intestines was converted to citrulline. Quantitatively glutamine was the only important precursor for intestinal citrulline release. Both glutamine and citrulline were consumed and produced by the liver, but net hepatic flux of both amino acids was not significantly different from zero. Plasma glutamine was the precursor of 80% of plasma citrulline and plasma citrulline in turn was the precursor of 10% of plasma arginine. In conclusion, glutamine is an important precursor for the synthesis of arginine after intestinal conversion to citrulline in humans. [source] A phase 2 pilot trial of low-dose, continuous infusion, or "metronomic" paclitaxel and oral celecoxib in patients with metastatic melanomaCANCER, Issue 7 2010Rupal S. Bhatt MD Abstract BACKGROUND: Tumor angiogenesis has been associated with a poor prognosis in patients with metastatic melanoma (MM). Microtubule stabilizers and cyclooxygenase 2 (COX-2) inhibitors, alone and in combination, have produced inhibitory effects on endothelial cells and tumor angiogenesis. Angiogenesis, which is the growth of new blood vessels, is necessary for tumor growth and progression. Thus, the authors tested the safety and efficacy of a low dose of paclitaxel and celecoxib in patients with MM. METHODS: Patients received paclitaxel 10 mg/m2 for 96 hours weekly as a continuous intravenous infusion and oral celecoxib 400 mg twice daily. Systemic tumor response was assessed at 6-week intervals. Tumor measurements at the end of Cycle 1 were used as the baseline for assessment of tumor progression. Patients with unacceptable toxicity or disease progression after Cycle 2 relative to the end of Cycle 1 were taken off study. RESULTS: Twenty patients were enrolled. Twelve of 20 patients (60%) had received ,2 previous systemic therapies. Three patients did not receive treatment because of rapid disease progression. Treatment-related grade 3/4 toxicities were limited to catheter-related complications. One patient achieved a partial response, and 3 of 20 patients (15%) had stable disease for >6 months. The median time to progression was 57 days (95% confidence interval, 43-151 days), and the median overall survival was 212 days (95% confidence interval, 147-811 days). CONCLUSIONS: Low-dose, continuous intravenous infusion paclitaxel and oral celecoxib produced disease stabilization in a significant proportion of heavily pretreated patients with MM. These findings support a role for metronomic therapy in patients with this disease. Cancer 2010. © 2010 American Cancer Society. [source] Long-term follow-up of autologous stem cell transplantation in patients with diffuse mantle cell lymphoma in first disease remissionCANCER, Issue 12 20032 -microglobulin, The prognostic value of, the tumor score Abstract BACKGROUND The current study was conducted to analyze the long-term results of autologous stem cell transplantation (ASCT) in patients with diffuse mantle cell lymphoma (MCL) in first disease remission. METHODS Thirty-three patients were treated. Thirty-one patients had Ann Arbor Stage III or Stage IV disease. The hyper-CVAD regimen (hyperfractionated intense-dose cyclophosphamide, vincristine, continuous intravenous infusion of doxorubicin, and dexamethasone, alternating with high doses of cytarabine and methotrexate plus leucovorin rescue) was used for cytoreduction before ASCT. Patients were consolidated with high-dose cyclophosphamide (120 mg/kg), total body irradiation, and ASCT. RESULTS At a median follow-up of 49 months, the overall survival and disease-free-survival rates at 5 years were estimated to be 77% and 43%, respectively. Patients whose M. D. Anderson Lymphoma Tumor Score (TS) was , 1 at the time of diagnosis or transplantation experienced longer disease-free survival compared with those whose TS was > 1 (P = 0.02). A ,2 -microglobulin (,2m)level , 3 mg/L at the time of diagnosis or transplantation was also found to be strongly predictive of longer survival (5-year survival rate of 100% vs. 22% in patients with a ,2m level > 3 mg/L) (P = 0.0001). CONCLUSIONS ASCT may prolong the overall survival in a subset of patients with MCL. This improvement has been observed for the most part in patients with low ,2m levels (, 3 mg/L) and TS (, 1). Randomized trials are required to fully assess the benefits of this strategy. Cancer 2003;98:2630,5. © 2003 American Cancer Society. [source] Remifentanil analgosedation in preterm newborns during mechanical ventilationACTA PAEDIATRICA, Issue 7 2009Carmen Giannantonio Abstract Aim:, To assess efficacy of remifentanil in preterm newborns during mechanical ventilation. Methods:, Remifentanil was administered by continuous intravenous infusion to provide analgesia and sedation in 48 preterm infants who developed respiratory distress and required mechanical ventilation. We examined the doses needed to provide adequate analgesia, extubation time after the discontinuation of opioid infusion, the presence of side effects and safety of the use. Results:, Remifentanil provided adequate analgesia, with a significant reduction of NIPS and COMFORT score since 1 h after starting the infusion of remifentanil. The drug was initially administered at a dose of 0.075 ,g/kg/min, but in 73% of newborns the latter had to be increased; at a dose of 0.094 ± 0.03 (mean ± standard deviation) ,g/kg/min, 97% of the newborns received adequate analgesia and sedation. The time elapsed between the discontinuation of remifentanil infusion and extubation was 36 ± 12 min. Treatment was started between the 1st and the 17th day of life. The mean duration of therapy was 5.9 ± 5.7 days. No side effects on the respiratory or cardiovascular system were observed. Conclusion:, Remifentanil is a manageable and effective opioid in the newborn undergoing mechanical ventilation, though randomized controlled trials and information about long-term outcomes are necessary. [source] Multiple Inert Gas Elimination Technique For Determining Ventilation/Perfusion Distributions In Rat During Normoxia, Hypoxia And HyperoxiaCLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 5-6 2001V Alfaro SUMMARY 1. The use of the multiple inert gas elimination technique (MIGET) in quantifying ventilation/perfusion distributions (V,A/Q,) in small animals, such as the rat, may cause results to be biased due to haemodilution produced by the large volume of liquid infused intravenously. 2. We tested two methods of administering inert gases in rats using the MIGET: (i) standard continuous intravenous administration of inert gases (method A); and (ii) a new method based on the physicochemical properties of each inert gas (method B). This method included acute simultaneous inert gas administration using three pathways: inhalation, intravenous infusion and rectal infusion. Both MIGET methods were applied to obtain data while breathing three different inspiratory fractions of oxygen (FIO2): normoxia, hypoxia and hyperoxia. 3. Inert gas levels obtained from blood or expired air samples were sufficient for chromatographic measurement, at least during a 2 h period. The V,A/Q, distributions reported using both methods were acceptable for all the physiological conditions studied; therefore, the alternative method used here may be useful in further MIGET studies in rats because haemodilution resulting from continuous intravenous infusion of less-soluble gases can be avoided. 4. Normoxic rats showed lower mean values of the V,A/Q, ratio of ventilation distribution and higher mean values of the V,A/Q, ratio of perfusion distribution with the usual method of inert gas administration (method A). These non-significant differences were observed under almost all physiological conditions studied and they could be caused by haemodilution. Nevertheless, the effect of interindividual differences cannot be discarded. An additional effect of the low haematocrit on cardiovascular changes due to low FIO2, such as pulmonary vasoconstriction or increased cardiac output, may explain the lower dispersion of perfusion distributions found in group A during hypoxia. 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