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Biomedical subjects

P Netter

Publications and source records attributed to P Netter.

At least 145 records · Page 8Linked to original sources
PubMed1988

Risk-benefit ratio of sodium fluoride treatment in primary vertebral osteoporosis.

The risk-benefit ratio of combined fluoride-calcium therapy in primary vertebral osteoporosis was examined prospectively in patients with at least one vertebral fracture. 257 patients were randomised to receive sodium fluoride 25 mg twice daily plus elemental calcium 1 g daily and a vitamin D2 supplement, and 209 received one of the alternative therapies usually prescribed in France. After a follow-up of 24 months the fluoride-calcium group showed a significantly lower rate of new vertebral fractures, the main adverse effect of the regimen being a higher incidence of osteoarticular pains in the ankle and foot; the risk of non-vertebral fractures was not increased, and digestive disorders arose with equal frequency in the two groups. Sodium fluoride 50 mg daily seems to represent a reasonable compromise in terms of anti-fracture effectiveness and side-effects.

Administration, Oral↗
PubMed1988

[Joint complications in patients with chronic renal failure hemodialyzed for over 10 years. 40 cases].

A retrospective study of 40 patients with chronic renal failure who underwent haemodialysis for more than 10 years (mean: 153 months) showed that 18 patients (45 p. 100) had arthralgia in the shoulders, hands, wrists and knees, 13 (32 p. 100) had carpal tunnel syndrome requiring surgery, and 20 (50 p. 100) were found to have bone cavities in the humeral head, external supra-acetabular region, carpus and patella. Aluminium overload was present in 47 p. 100 of the patients, and amyloid deposits were found in 10 of the 12 patient operated upon for carpal tunnel syndrome. This study confirms the frequency in patients under long-term haemodialysis of an articular pathological entity consisting of arthralgia, carpal tunnel syndrome, juxta-articular bone cavities and amyloid deposits which are now known to be made of beta 2-microglobulin. The initial lesion seems to affect the synovial membrane; it appears to be facilitated by age and is often associated with aluminium overload. The mechanism(s) responsible for amyloid deposits remain (s) to be elucidated.

Adolescent↗
PubMed1988

Individual differences in benzodiazepine-induced changes of memory.

Antero- and retrograde amnesia are observed as side effects of most types of benzodiazepines. They have rarely been investigated with respect to physical and personality factors, or to prior experiences, present expectations, and emotional states of the subjects, all of which are well known to modify drug response. By reviewing research on benzodiazepine-induced changes of memory in preoperative, anxious, and depressed patients as well as in healthy subjects, it is demonstrated that differences in benzodiazepine-induced amnesic effects may depend on: 1. subject variables like predrug level of anxiety, depressive symptomatology, memory capacity, experiences with benzodiazepine-type drugs, and expectations of treatment outcome, and secondary factors like social environment and treatment setting 2. interactions between these subject variables and type of schedule (times of acquisition, treatment, and testing), type of learning material, and dose of drug. 3. the extent of benzodiazepine-induced changes in anxiety or depression, cortical and emotional arousal (alertness and activity) as well as physiological effects of benzodiazepines Special emphasis should be placed on the investigation of drug-induced changes of covariation between psychological measures which may provide valuable information for differential prediction and on mechanisms of drug action.

Anti-Anxiety Agents↗
PubMed1988

The effect of food on the systemic availability of ketoprofen.

We have studied the pharmacokinetics of ketoprofen, a non-steroidal anti-inflammatory drug, in 12 patients after a single 100 mg oral dose both in fasting conditions and with a meal. Food significantly affected the peak plasma concentration of ketoprofen and decreased its absorption rate. However, the extent of absorption of ketoprofen, as reflected by the area under the plasma concentration time curve, appeared to be unchanged in the presence of food.

Administration, Oral↗
PubMed1988

Effects of changes in brain 5-HT activity on indicators of cortical arousal.

Clinical studies on fluoxetine have reported occasional symptoms of increased fatigue in depressed patients. On the other hand, experimental studies in healthy subjects have demonstrated evidence for fluoxetine-induced increases in cortical arousal. The present placebo-controlled study with 24 healthy subjects was designed to answer the following questions: Does fluoxetine increase measures of cortical arousal and decrease feelings of alertness, and does the 5HT2 receptor blocker ritanserin produce inverse effects to fluoxetine? Analyses of covariance revealed the following results: Fluoxetine produced a slight increase, ritanserin a marked decrease in critical flicker fusion frequency. Time perception was slightly improved by both drugs. Self-ratings on alertness and energy were significantly reduced by both fluoxetine and ritanserin as compared to placebo. Effects for fatigue were increased accordingly. Possible underlying neurophysiological mechanisms and specificity of the effects for cortical as opposed to limbic arousal will be discussed.

Adult↗
PubMed1987

Total and free ketoprofen in serum and synovial fluid after intramuscular injection.

Free and total ketoprofen levels in serum and synovial fluid were determined in 37 patients after a single intramuscular injection of ketoprofen, 100 mg. Free drug was separated by equilibrium dialysis. Ketoprofen was assayed by HPLC. Ketoprofen penetrated into the joints rapidly and significant concentrations were found at 15 minutes. The equilibrium time was about 3 1/2 hours. The AUC for total ketoprofen was greater in serum than in synovial fluid. On the other hand, the free fraction AUC in the serum and synovial fluid were quite similar. The mean residence time in the joint was about three times that in the systemic circulation. Ketoprofen was strongly bound to proteins and the percentage of free ketoprofen was not significantly different between serum and synovial fluid. These results provide a possible explanation for duration of the therapeutic effect of ketoprofen despite the short elimination half-life from the serum.

Adolescent↗
PubMed1987

Clinical pharmacokinetics of D-penicillamine.

Penicillamine exists as 2 stereoisomers, but only the D-isomer is used therapeutically. Its chemical reactivity derives from its functional groups, of which the thiol group seems the most important. It is difficult to determine penicillamine in biological fluids because of its instability, the presence of endogenous compounds with a thiol function, and the various chemical forms in which it occurs, namely reduced free penicillamine, penicillamine bound to proteins, and internal (P-S-S-P) and mixed (P-S-S-C) disulphides. The earliest assay methods (colourimetry, isotopic methods, gas-phase chromatography) were neither sensitive nor specific. High performance liquid chromatography with electrochemical detection has led to a more specific assay for D-penicillamine, with detection based on either derivatisation reactions or on electro-oxidisation of the thiol function. With dual-electrode detectors (Au/Hg) disulphides can be assayed directly. D-penicillamine is absorbed rapidly but incompletely (40 to 70%) in the intestine, with wide interindividual variations. Food, antacids and, in particular, iron reduce absorption of the drug. Its bioavailability is also dramatically decreased in patients with malabsorption states. The peak plasma concentration occurs at 1 to 3 hours after ingestion, regardless of dose, and is of the order of 1 to 2 mg/L after an oral dose of 250 mg; some investigators have reported a double peak in plasma, which is probably not due to an enterohepatic cycle. The concentration in plasma then decreases rapidly, generally following a biphasic curve. When long term treatment is discontinued, there is a slow elimination phase lasting 4 to 6 days, which suggests that there is a 'deep compartment' or 'slow pool of the drug reversibly bound to tissues', particularly the skin. This may explain the persistence of its therapeutic effect and the occurrence of undesirable side effects after treatment has been stopped. During long term treatment plasma concentrations are highly variable between individuals. They do not seem to be correlated with the activity or the toxicity of D-penicillamine in patients with rheumatoid arthritis. More than 80% of plasma D-penicillamine is bound to proteins, particularly albumin. The rest is mainly in the free reduced form or as disulphides. Only a small portion of the dose is metabolised in the liver to S-methyl-D-penicillamine. The route of elimination is mainly renal; disulphides represent the main compounds found in the urine. Faecal excretion corresponds mainly to the non-absorbed fraction of the drug.

Chromatography, High Pressure Liquid↗