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1.
Can Prosthet Orthot J ; 6(1): 41605, 2023.
Article in English | MEDLINE | ID: mdl-38873009

ABSTRACT

BACKGROUND: There is a dearth of literature evaluating the accuracy of Air Displacement Plethysmography (ADP) compared to Dual-energy X-ray Absorptiometry (DXA) for assessing body composition in individuals with lower limb amputations. Validity of ADP in persons with lower limb amputations must be established. OBJECTIVE: The objective of this study was to compare body composition in persons with lower limb amputations using the BOD POD® and DXA. METHODOLOGY: Body composition was performed on eleven lower limb prosthesis users (age 53.2±14.3 years, weight 81.9±22.3kg) using ADP and DXA with and without prosthesis. FINDINGS: Repeated measures ANOVA indicated no significant difference in body composition among and between trials, F(3,8)= 3.36, p= 0.075. There were no significant differences in Body Fat (BF) percentage with and without prostheses on the BOD POD (28.5±15.7% and 33.7±12.1%, respectively) nor the DXA (32.9±10.6% and 32.0±9.9%, respectively). Association between the BOD POD and DXA were greatest when prostheses were not worn compared to when they were worn. Bland-Altman plots indicate agreement between BOD POD® and DXA was greatest while wearing the prosthesis. CONCLUSION: This study is a first to compare total body fat percent between the BOD POD® and DXA in lower limb prosthesis users. BOD POD® report valid indices of BF%. Future work will utilize the BOD POD® in intervention studies for monitoring body composition changes across the continuum of rehabilitation.

2.
Eur J Neurol ; 26(11): 1417-1420, 2019 11.
Article in English | MEDLINE | ID: mdl-31230396

ABSTRACT

BACKGROUND AND PURPOSE: The aim was to analyze the characteristics and progression of cognitive dysfunction in non-demented idiopathic rapid eye movement sleep behavior disorder (iRBD) patients with baseline olfactory function. METHODS: From a prospective polysomnography-confirmed iRBD cohort, 25 patients (16 patients in 2-year follow-up) and 13 normal controls were included. Initial and 2-year follow-up cognitive functions were analyzed with olfactory function and 18 F-fluorinated-N-3-fluoropropyl-2ß-carboxymethoxy-3ß-(4-iodophenyl)-nortropane (18 F-FP-CIT) uptake in deep nuclei initially. RESULTS: Idiopathic RBD patients had impaired attention, memory and executive function compared to controls. Baseline cognitive tests were comparable between the iRBD subgroups with and without hyposmia. 18 F-FP-CIT uptake tended to be lower in the hyposmic group than in the normosmic group. The olfactory test score was positively correlated with amygdala uptake in iRBD patients (P = 0.027). After 2 years, visuospatial and verbal memory dysfunction worsened more in hyposmics than in normosmics. Lower initial olfactory test score was associated with more severe declines in verbal memory function. CONCLUSIONS: Hyposmia may be a predictive sign of cognitive decline in iRBD patients.


Subject(s)
Cognitive Dysfunction/etiology , Cognitive Dysfunction/psychology , Olfaction Disorders/complications , Olfaction Disorders/psychology , REM Sleep Behavior Disorder/complications , REM Sleep Behavior Disorder/psychology , Aged , Attention Deficit Disorder with Hyperactivity/etiology , Cognitive Dysfunction/diagnostic imaging , Executive Function , Female , Follow-Up Studies , Humans , Male , Memory Disorders/etiology , Middle Aged , Neuropsychological Tests , Olfaction Disorders/diagnostic imaging , Polysomnography , Predictive Value of Tests , Prospective Studies , Psychomotor Performance , REM Sleep Behavior Disorder/diagnostic imaging , Tomography, Emission-Computed, Single-Photon , Tropanes
3.
Clin Microbiol Infect ; 22(7): 644.e7-644.e12, 2016 Jul.
Article in English | MEDLINE | ID: mdl-27108966

ABSTRACT

The clinical course of a case of infant botulism was characterized by several relapses despite therapy with amoxicillin and metronidazole. Botulism was confirmed by identification of botulinum toxin and Clostridium botulinum in stools. A C. botulinum A2 strain resistant to penicillins and with heterogeneous resistance to metronidazole was isolated from stool samples up to 110 days after onset. Antibiotic susceptibility was tested by disc agar diffusion and MICs were determined by Etest. Whole genome sequencing allowed detection of a gene cluster composed of blaCBP for a novel penicillinase, blaI for a regulator, and blaR1 for a membrane-bound penicillin receptor in the chromosome of the C. botulinum isolate. The purified recombinant penicillinase was assayed. Resistance to ß-lactams was in agreement with the kinetic parameters of the enzyme. In addition, the ß-lactamase gene cluster was found in three C. botulinum genomes in databanks and in two of 62 genomes of our collection, all the strains belonging to group I C. botulinum. This is the first report of a C. botulinum isolate resistant to penicillins. This stresses the importance of antibiotic susceptibility testing for adequate therapy of botulism.


Subject(s)
Anti-Bacterial Agents/pharmacology , Botulism/diagnosis , Botulism/microbiology , Clostridium botulinum/drug effects , Clostridium botulinum/isolation & purification , Drug Resistance, Bacterial , Metronidazole/pharmacology , Penicillins/pharmacology , Botulinum Toxins/analysis , Botulism/drug therapy , Botulism/pathology , Feces/chemistry , Feces/microbiology , Female , Genes, Regulator , Genome, Bacterial , Humans , Infant , Membrane Transport Proteins/genetics , Microbial Sensitivity Tests , Multigene Family , Penicillinase/genetics , Penicillinase/isolation & purification , Penicillinase/metabolism , Sequence Analysis, DNA
4.
Mol Pharmacol ; 70(1): 311-8, 2006 Jul.
Article in English | MEDLINE | ID: mdl-16638972

ABSTRACT

Phospholipase D-mediated hydrolysis of phosphatidylcholine is stimulated by protein kinase C and the monomeric G proteins Arf, RhoA, Cdc42, and Rac1, resulting in complex regulation of this enzyme. Using purified proteins, we have identified a novel inhibitor of phospholipase D activity, Gbetagamma subunits of heterotrimeric G proteins. G protein-coupled receptor activation alters affinity between Galpha and Gbetagamma subunits, allowing subsequent interaction with distinct effectors. Gbeta1gamma1 inhibited phospholipase D1 and phospholipase D2 activity, and both Gbeta1gamma1 and Gbeta1gamma2 inhibited stimulated phospholipase D1 activity in a dosedependent manner in reconstitution assays. Reconstitution assays suggest this interaction occurs through the amino terminus of phospholipase D, because Gbeta1gamma1 is unable to inhibit an amino-terminally truncated phospholipase D construct, PLD1.d311, which like full-length phospholipase D isoforms, requires phosphatidylinositol-4,5-bisphosphate for activity. Furthermore, a truncated protein consisting of the amino-terminal region of phospholipase D containing the phox/pleckstrin homology domains was found to interact with Gbeta1gamma1, unlike the PLD1.d311 recombinant protein, which lacks this domain. In vivo, expressed recombinant Gbeta1gamma2 was also found to inhibit phospholipase D activity under basal and stimulated conditions in MDA-MB-231 cells, which natively express both phospholipase D1 and phospholipase D2. These data demonstrate that Gbetagamma directly regulates phospholipase D activity in vitro and suggest a novel mechanism to negatively regulate phospholipase D signaling in vivo.


Subject(s)
Heterotrimeric GTP-Binding Proteins/metabolism , Phospholipase D/metabolism , Binding Sites , Cell Line, Tumor , Choline/metabolism , Dose-Response Relationship, Drug , Enzyme Activation , GTP-Binding Protein beta Subunits/chemistry , GTP-Binding Protein beta Subunits/genetics , GTP-Binding Protein beta Subunits/metabolism , GTP-Binding Protein gamma Subunits/chemistry , GTP-Binding Protein gamma Subunits/genetics , GTP-Binding Protein gamma Subunits/metabolism , Heterotrimeric GTP-Binding Proteins/genetics , Heterotrimeric GTP-Binding Proteins/pharmacology , Humans , Immunoblotting , Phospholipase D/antagonists & inhibitors , Phospholipase D/genetics , Protein Binding , Transfection , Tritium
5.
Neurosci Lett ; 279(2): 81-4, 2000 Jan 28.
Article in English | MEDLINE | ID: mdl-10674626

ABSTRACT

The present communication reports the isolation and characterization of three new zebrafish elav/Hu (Kim, C.-H., Ueshima, E., Muraoka, O., Tanaka, H., Yeo, S.-Y., Huh, T.-L. and Miki, N., Zebrafish elav/HuC homologue as a very early neuronal marker. Neurosci. Lett., 216 (1996) 109-112) homologues, HuA, HuD and HuG. While HuA and HuG showed weak and ubiquitous expressions, HuD, as well as HuC, were specifically expressed in the neuronal cells. The first expression of HuD was detectable of the 10-somite stage, that is, several hours later than HuC. After 24 h of embryonic development, although HuD and HuC expressions overlapped overall, the cells expressing HuD were restricted to subsets of the HuC-positive neuronal cells in the brain and spinal cord. These differentially regulated spatial and temporal expression patterns implied distinct roles for HuC and HuD in neuronal determination and neuronal differentiation, respectively.


Subject(s)
Antigens, Surface/genetics , Brain/embryology , Gene Expression Regulation, Developmental , Nerve Tissue Proteins/genetics , Neurons/physiology , RNA-Binding Proteins/genetics , Spinal Cord/embryology , Zebrafish Proteins , Zebrafish/embryology , Zebrafish/genetics , Amino Acid Sequence , Animals , Antigens, Surface/chemistry , ELAV Proteins , ELAV-Like Protein 3 , Molecular Sequence Data , Nerve Tissue Proteins/chemistry , RNA-Binding Proteins/chemistry , Sequence Alignment , Sequence Homology, Amino Acid
6.
J Am Geriatr Soc ; 47(7): 784-91, 1999 Jul.
Article in English | MEDLINE | ID: mdl-10404920

ABSTRACT

OBJECTIVES: The purpose of this study was to test whether an intervention combining increased daytime physical activity with improvement in the nighttime environment improves sleep and decreases agitation in nursing home residents. DESIGN: A randomized trial. SETTING: One community nursing home in the Los Angeles, California area. PARTICIPANTS: Twenty-nine incontinent residents (mean age 88.3 years, 90% female). INTERVENTION: Subjects were randomized to receive either (1) an intervention combining increased daytime physical activity (14 weeks in duration) plus a nighttime program (5 nights in duration) to decrease noise and sleep-disruptive nursing care practices (intervention group), or (2) the nighttime program alone (control group). MEASUREMENTS: Daytime physical activity monitors and structured physical function assessments; nighttime wrist activity monitors to estimate nighttime sleep; and timed daytime behavioral observations of sleep versus wakefulness, either in or out of bed, and agitation. RESULTS: Physical function measures did not change significantly (MANOVA for repeated measures, group by time effect). Wrist actigraphy estimation of nighttime percent sleep (time asleep over time monitored in bed at night) increased in intervention subjects from 51.7% at baseline to 62.5% at follow-up compared with 67.0% at baseline to 66.3% at follow-up in controls (MANOVA, group by time, F = 4.42, P = .045, df = 27). At follow-up, intervention subjects averaged a 32% decrease in the percent of daytime observations in bed compared with baseline, with essentially no change in controls (MANOVA, group by time, F = 5.31, P = .029, df = 27). Seven of 15 intervention subjects had a decrease in observed agitation at follow-up, compared with baseline, versus only 1 of 14 controls with a decrease in observed agitation. CONCLUSIONS: This study provides preliminary evidence that an intervention combining increased physical activity with improvement in the nighttime nursing home environment improves sleep and decreases agitation in nursing home residents.


Subject(s)
Exercise Therapy , Health Facility Environment , Night Care/methods , Nursing Homes , Psychomotor Agitation/prevention & control , Sleep Wake Disorders/prevention & control , Urinary Incontinence/nursing , Aged , Aged, 80 and over , Female , Follow-Up Studies , Humans , Los Angeles , Male , Multivariate Analysis , Noise/prevention & control , Polysomnography , Sleep Wake Disorders/diagnosis , Sleep Wake Disorders/etiology
7.
Drug Metab Dispos ; 25(1): 66-74, 1997 Jan.
Article in English | MEDLINE | ID: mdl-9010632

ABSTRACT

Pharmacokinetic parameters-including tissue distribution, biliary excretion, and urinary excretion of M1-M4-were compared after an intravenous administration of DA-125 (a new anthracycline derivative; 20 mg/kg body weight) to male spontaneously hypersensitive rats (SHRs) at 16 weeks (an animal model for human primary hypertension) and at 6 weeks (corresponding to the early phase of the development of hypertension, at which time blood pressure remains within the normotensive range) of age and their age-matched control Kyoto-Wistar rats, and male deoxycorticosterone acetate-salt-induced Sprague-Dawley rats (DOCA-salt rats, an animal model for human secondary hypertension) at 16 weeks of age and their age-matched control Sprague-Dawley rats. Mean plasma concentrations of both M2 and M4, and the resultant area under the plasma concentration-time curve from time 0 to last measured time [AUCT; M2 (68.9 vs. 29.3 micrograms-min/ml) and M4 (53.4 vs. 33.4 micrograms-min/ml)], increased significantly in SHRs at 16 weeks of age, compared with their control rats. Similar results were also obtained from DOCA-salt rats at 16 weeks of age, compared with their control rats. However, values were not significantly different between SHRs at 6 weeks of age and their control rats. Previous data indicated that the significant increase in plasma concentrations and the resultant AUCT values of both M2 and M4 in SHRs at 16 weeks of age were due to the hypertension state itself, and not to any hereditary characteristics of the SHRs. The significantly increased plasma concentrations and the resultant AUCT values of M2 in both SHRs and DOCA-salt rats at 16 weeks of age were due to the significantly decreased biliary excretion of M2 and possibly to the increased amount of aldo-keto reductase in the liver. However, the increase in the two aforementioned pharmacokinetic parameters in the case of M4 were possibly due solely to the increased amount of aldo-keto reductase in the liver.


Subject(s)
Antibiotics, Antineoplastic/pharmacokinetics , Doxorubicin/analogs & derivatives , Hypertension/metabolism , Age Factors , Alcohol Oxidoreductases/metabolism , Aldehyde Reductase , Aldo-Keto Reductases , Animals , Antibiotics, Antineoplastic/metabolism , Bile/chemistry , Desoxycorticosterone , Doxorubicin/metabolism , Doxorubicin/pharmacokinetics , Hypertension/blood , Hypertension/chemically induced , Hypertension/urine , Liver/enzymology , Male , Rats , Rats, Inbred SHR , Rats, Inbred WKY , Rats, Sprague-Dawley , Sodium Chloride
8.
Biopharm Drug Dispos ; 17(5): 373-420, 1996 Jul.
Article in English | MEDLINE | ID: mdl-8830976

ABSTRACT

The pharmacokinetics of M1, M2, M3 and/or M4 were compared after intravenous (i.v.) administration of DA-125 and/or ME2303 to mice (25 mg kg(-1)) and rats (5, 10, 20, 30, and 40 mg kg(-1)). The mean plasma concentrations of M1 were detected up to 8 h after i.v. administration of both DA-125 and ME2303 to mice, and were significantly higher for DA-125 than ME2303; this resulted in a considerably greater AUC (303 against 148 micrograms min mL(-1)) and a considerably slower CL of M1 (69.3 against 136 mL min-1 kg(-1)) after i.v. administration of DA-125. The MRT (371 against 189 min) and CLNR of M1 (68.7 against 136 mL min-1 kg(-1)) were considerably greater and slower, respectively, after i.v. administration of DA-125. The mean plasma concentrations of M2 were detected up to 8 and 4 h after i.v. administration of DA-125 and ME2303, respectively, to mice and were significantly higher for DA-125 than ME2303, resulting in a considerably greater AUC of M2 (148 against 27.1 micrograms min mL(-1)) after i.v. administration of DA-125. The mean plasma concentrations of M3, being the lowest among M1-M4, were detected only up to 15 min after i.v. administration of both DA-125 and ME2303 to mice, and were comparable after i.v. administration of DA-125 and ME2303 to mice. The mean plasma concentrations of M4 were detected up to 8 h after i.v. administration of both DA-125 and ME2303 to mice, and were higher after i.v. administration of DA-125 than ME2303, resulting in a considerably greater AUC of M4 (197 against 61.9 micrograms min mL(-1)) after i.v. administration of DA-125. Similar results on M1 and M2 were also obtained from rats: the mean plasma concentrations of both M1 and M2 were significantly higher after i.v. administration of DA-125, 10 mg kg(-1), than after ME2303. The plasma concentrations of M1, M2, and M4, and hence their AUCs, were significantly higher after i.v. administration of DA-125, 5, 10, 20, 30, and 40 mg kg(-1), to rats than after ME2303: the mean plasma concentrations of M2, approximately 0.1-0.4 micrograms mL(-1), were maintained from 30 min to 8-10 h after i.v. administration of DA-125, 20, 30, and 40 mg kg(-1), to rats; the plasma concentrations of M3 were the lowest among M1-M4 at all DA-125 doses; and those of M1 and M4 were maintained for a long period of time. However, after i.v. administration of M2, 5 mg kg(-1), to rats, the mean plasma concentrations of M2 were detected up to 60 min with a mean terminal half-life of only 38.8 min, and the concentrations of M3 were negligible. After i.v. administration of M3, 5 mg kg(-1), to rats, the mean plasma concentrations of M3 were detected up to 15 min; the plasma concentrations of M4, reaching their peak at 5 min, decayed more slowly and were higher than those of M3. The AUC of M4 after i.v. administration of M3, 5 mg kg(-1), was comparable to that after i.v. administration of M4, 5 mg kg(-1), to rats, suggesting that M4 is formed fast and almost completely from M3. M1 was not detected in plasma after i.v. administration of either M2 or M3 to rats. After i.v. administration of M4, 5 mg kg(-1), to rats, the mean plasma concentrations of M4 decayed fast with a mean terminal half-life of 43.9 min and neither M2 nor M3 were detected in plasma. The following disposition mechanisms for M1, M2, M3, and M4 after i.v. administration of DA-125 to rats could be obtained from the above data; (i) the maintenance of plasma concentrations of M2 for a longer period of time after i.v. administration of DA-125 than those after i.v. administration of M2 could be due to the continuous formation of M2 from M1; (ii) the lowest plasma concentrations of M3 among M1-M4 after i.v. administration of DA-125 could be due to the fast and almost complete information of M4 from M3 as soon as M3 is formed from M1, and not due to the fast renal excretion of unchanged M3; (iii) M4 was exclusively and continuously formed from M3 and the formation of M4 from M2 was negligible; and (i.v.) reversible me


Subject(s)
Anti-Infective Agents/pharmacokinetics , Doxorubicin/analogs & derivatives , Animals , Anti-Infective Agents/administration & dosage , Anti-Infective Agents/blood , Anti-Infective Agents/metabolism , Bile/metabolism , Chromatography, High Pressure Liquid , Dose-Response Relationship, Drug , Doxorubicin/administration & dosage , Doxorubicin/blood , Doxorubicin/metabolism , Doxorubicin/pharmacokinetics , Gastric Mucosa/metabolism , Hydrogen-Ion Concentration , In Vitro Techniques , Injections, Intravenous , Intestine, Small/metabolism , Kidney/metabolism , Liver/metabolism , Lung/metabolism , Male , Mice , Mice, Inbred ICR , Myocardium/metabolism , NADP/administration & dosage , NADP/pharmacology , Rabbits , Rats , Rats, Sprague-Dawley , Rats, Wistar , Species Specificity , Tissue Distribution
9.
Biopharm Drug Dispos ; 17(3): 183-95, 1996 Apr.
Article in English | MEDLINE | ID: mdl-8983394

ABSTRACT

The pharmacokinetics of DA-125 were compared after intravenous (i.v.) administration of the drug, 10 mg kg-1, to control male Sprague-Dawley rats (n = 9) and uranyl nitrate-induced acute renal failure (U-ARF, n = 12) rats, or male Sprague-Dawley rats fed on a 23% (control, n = 8) or a 5% (protein-calorie malnutrition, PCM, n = 9) protein diet. After i.v. administration of DA-125, almost 'constant' plasma concentrations of M1, M2, and M4 were maintained from 1-2 h to 8-10 h in all rat groups due to the continuous formation of M2 from M1 and M4 from M3. The plasma concentrations of M3 were the lowest among M1-M4 for all rat groups due to the rapid and almost complete conversion of M3 to M4 and other metabolite(s). The AUCt values of M1 (115 against 82.5 micrograms min mL-1), M2 (33.0 against 23.6 micrograms min mL-1), and M4 (26.3 against 15.1 micrograms min mL-1) were significantly higher in the U-ARF rats than in the control rats. The percentages of i.v. dose excreted in 24 h urine as M1 (under the detection limit against 0.316%), M2 (under the detection limit against 5.58%), and M4 (0.0174 against 0.719%)--expressed in terms of DA-125--were significantly lower in the U-ARF rats than in the control rats, and this could be due to the decreased kidney function in the U-ARF rats. However, the percentages of i.v. dose recovered from the GI tract at 24 h as M1 (0.0532% against under the detection limit), M3 (0.0286% against under the detection limit), and M4 (0.702% against 0.305%)--expressed in terms of DA-125--were significantly greater in the U-ARF rats than in the control rats. All U-ARF rats had ascites, but the concentrations of M1 (0.0320 micrograms mL-1), M2 (0.0265 micrograms mL-1), M3 (under the detection limit), and M4 (0.032 micrograms mL-1) in the ascites from one rat were almost negligible. The plasma concentrations and most of the pharmacokinetic parameters of M1, M2, and M4 were not significantly different between the PCM rats and their control rats.


Subject(s)
Acute Kidney Injury/metabolism , Anti-Infective Agents/pharmacokinetics , Doxorubicin/analogs & derivatives , Kidney/metabolism , Protein-Energy Malnutrition/metabolism , Acute Kidney Injury/chemically induced , Animals , Anti-Infective Agents/blood , Anti-Infective Agents/urine , Doxorubicin/blood , Doxorubicin/pharmacokinetics , Doxorubicin/urine , Injections, Intravenous , Male , Organ Size/drug effects , Organ Specificity , Protein-Energy Malnutrition/chemically induced , Rats , Rats, Sprague-Dawley , Tissue Distribution , Uranyl Nitrate
10.
J Cereb Blood Flow Metab ; 15(5): 865-76, 1995 Sep.
Article in English | MEDLINE | ID: mdl-7673380

ABSTRACT

The in vivo neuroprotective effect and brain levels of cis-4-phosphonomethyl-2-piperidine carboxylic acid (CGS 19755), a competitive N-methyl-D-aspartate (NMDA) antagonist, were compared with its in vitro neuroprotective effects. The dose-response for in vitro neuroprotection against both NMDA toxicity and combined oxygen-glucose deprivation (OGD) was determined in murine neocortical cultures. Primary cultures of neocortical cells from feta mice were injured by exposure to 500 microM NMDA for 10 min or to OGD for 45 min. The effect of CGS 19755 in both injury paradigms was assessed morphologically and quantitated by determination of lactate dehydrogenase release. Near complete neuroprotection was found at high doses of CGS 19755. The ED50 for protection against NMDA toxicity was 25.4 micro M, and against OGD the ED50 was 15.2 microM. For the in vivo paradigm rabbits underwent 2 h of left internal carotid, anterior cerebral, and middle cerebral artery occlusion followed by 4 h reperfusion; ischemic injury was assessed by magnetic resonance imaging and histopathology. The rabbits were treated with 40 mg/kg i.v. CGS 19755 or saline 10 min after arterial occlusion. CSF and brain levels of CGS 19755 were 12 microM and 5 microM, respectively, at 1 h, 6 microM and 5 microM at 2 h, and 13 microM and 7 microM at 4 h. These levels were neuroprotective in this model, reducing cortical ischemic edema by 48% and ischemic neuronal damage by 76%. These results suggest that a single i.v. dose penetrates the blood-brain barrier, attaining sustained neuroprotective levels that are in the range for in vitro neuroprotection.


Subject(s)
Brain Ischemia/physiopathology , Neuroprotective Agents/pharmacology , Neurotoxins/pharmacology , Pipecolic Acids/pharmacology , Animals , Brain/metabolism , Brain/pathology , Brain Ischemia/diagnosis , Cerebrovascular Circulation/drug effects , Evoked Potentials, Somatosensory , In Vitro Techniques , Magnetic Resonance Imaging , Male , Mice/embryology , N-Methylaspartate/metabolism , Pipecolic Acids/pharmacokinetics , Rabbits
11.
Neuroscience ; 64(1): 99-107, 1995 Jan.
Article in English | MEDLINE | ID: mdl-7708219

ABSTRACT

While N-methyl-D-aspartate antagonists have been shown to attenuate neuronal damage in focal cerebral ischemia, few studies have examined whether continuous or multiple dose treatment is necessary for maximum efficacy. We studied the effect of a loading dose only or load plus maintenance infusion using several non-competitive N-methyl-D-aspartate antagonists (dextromethorphan, dextrorphan, MK-801) and the levorotatory enantiomer of dextromethorphan (levomethorphan) in a rabbit model of focal cerebral ischemia. Forty-seven anesthetized rabbits underwent occlusion of the left internal carotid, anterior cerebral and middle cerebral arteries for 2 h followed by 4 h of reperfusion. Drugs were administered 10 min after occlusion. Dextromethorphan and dextrorphan protected against ischemic edema only when given as load plus maintenance (29% and 31% reduction, respectively), while both load only and load plus maintenance of MK-801 protected against edema (26% and 31% reduction, respectively). Levomethorphan load plus maintenance also protected against ischemic edema (25% reduction). However, dextromethorphan and dextrorphan both required maintenance infusion to protect against ischemic neuronal damage (24% and 27% reduction in area of ischemic neuronal damage, respectively), while levomethorphan failed to protect against neuronal injury even when given as load plus maintenance. Administration of MK-801 as load plus maintenance reduced ischemic neuronal damage by 23%, but this difference was not quite statistically significant. These results suggest that processes of ischemic damage, such as excitotoxic injury, continue for several hours beyond the initial period of focal ischemia, and that non-competitive N-methyl-D-aspartate antagonists require more prolonged administration to achieve neuroprotection.(ABSTRACT TRUNCATED AT 250 WORDS)


Subject(s)
Brain Ischemia/prevention & control , N-Methylaspartate/antagonists & inhibitors , Neuroprotective Agents , Animals , Body Temperature , Brain Edema/drug therapy , Brain Edema/pathology , Brain Ischemia/chemically induced , Brain Ischemia/drug therapy , Cerebral Cortex/drug effects , Corpus Striatum/drug effects , Dextromethorphan , Dextrorphan , Hydrogen-Ion Concentration , Oxygen/blood , Rabbits
12.
Biopharm Drug Dispos ; 15(5): 391-407, 1994 Jul.
Article in English | MEDLINE | ID: mdl-7981428

ABSTRACT

The pharmacokinetics and tissue distribution of methotrexate (MTX) were investigated after intravenous (i.v.) injection of free MTX (treatment I), MTX-loaded proliposomes (treatment II), and empty proliposomes mixed manually with free MTX (treatment III), 8 mg kg-1, to rats using an HPLC assay. After i.v. infusion in 1 min, the plasma concentration of MTX (Cp), the area under the plasma concentration-time curve (AUC, 639 versus 913 micrograms min mL-1), the terminal half-life (t1/2, 48.8 versus 397 min), the mean residence time (MRT, 8.40 versus 325 min), and the apparent volume of distribution at steady state (Vss, 98.1 versus 2800 mL kg-1) were significantly higher; however, the total body clearance (CL, 12.5 versus 8.76 mL min-1 kg-1), renal clearance (CLR, 4.49 versus 2.78 mL min-1 kg-1), non-renal clearance (CLNR, 7.50 versus 5.99 mL min-1 kg-1), and the amount of MTX excreted in urine (Xu, 808 versus 685 micrograms, p < 0.0948) were significantly lower from treatment II than from treatment I. This could be due to the fact that some of the MTX-loaded liposomes (formed immediately after hydration of MTX-loaded proliposomes) are entrapped in tissues and the rest are present in the plasma (higher MRT and Vss from treatment II), and MTX is slowly released from MTX-loaded liposomes (higher t1/2 from treatment II). In the present HPLC assay, the concentrations of MTX represent the sum of free MTX and MTX loaded in liposomes (higher Cp and AUC, slower CL from treatment II). After i.v. infusion in 1 min, some pharmacokinetic parameters, such as t1/2, MRT, and Vss, were significantly different between treatments I and III; however, the differences seemed to be smaller than those between treatments I and II. After 30 min from i.v. infusion, the tissue to plasma (T/P) ratios of MTX in kidney and stomach from treatment II were significantly lower than those from treatment I. This suggested that the i.v. administration of MTX-loaded proliposomes might have fewer side effects in the organs than that of free MTX. The mean amount of MTX loaded in MTX-loaded proliposomes was 2.54 mg/g proliposomes and the MTX was released slowly from hydrated MTX-loaded proliposomes when incubated with phosphate-buffered saline (PBS), rat plasma, or rat liver homogenate.


Subject(s)
Methotrexate/pharmacokinetics , Animals , Infusions, Intravenous , Liposomes , Male , Methotrexate/administration & dosage , Particle Size , Rats , Rats, Sprague-Dawley , Tissue Distribution
13.
J Chromatogr B Biomed Appl ; 656(2): 407-14, 1994 Jun 17.
Article in English | MEDLINE | ID: mdl-7987494

ABSTRACT

A high-performance liquid chromatographic method was developed for the simultaneous determination of a new anthracycline, DA-125 (I), and its metabolites (M1, M2, M3, and M4) in rat plasma and urine using fluorescein as an internal standard. Compound I, a prodrug of M1, is a beta-alanine derivative of M1, and only M1 shows antineoplastic activity. The method involved extraction or deproteinization followed by injection of 80-100 microliters of the aqueous layer or supernatant onto a C18 reversed-phase column. The mobile phases were 1% acetic acid-isopropyl alcohol-methanol (70:20:10, v/v) or 5 mM of ion-pairing chromatography reagent (IPC B8)-isopropyl alcohol-methanol (70:20:10, v/v) for the extraction or deproteinization methods, respectively. The flow-rate was 1.5 ml/min for both methods. The column effluent was monitored by a fluorescence detector with excitation wavelength of 488 nm and emission wavelength of 556 nm. The detection limits for M1, M2, M3, and M4 in rat plasma and urine were 50 ng/ml for all compounds using the extraction method, and 100, 50, 50, 50, and 50 ng/ml for I, M1, M2, M3 and M4 in rat plasma respectively, using the deproteinization method. No interferences from endogenous substances, adriamycin or daunorubicin were found.


Subject(s)
Antibiotics, Antineoplastic/pharmacokinetics , Doxorubicin/analogs & derivatives , Animals , Antibiotics, Antineoplastic/blood , Antibiotics, Antineoplastic/urine , Chromatography, High Pressure Liquid , Dogs , Doxorubicin/blood , Doxorubicin/pharmacokinetics , Doxorubicin/urine , Half-Life , Humans , Mice , Rats , Spectrometry, Fluorescence
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