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Biomedical subjects

F Duval

Publications and source records attributed to F Duval.

At least 37 records · Page 2Linked to original sources
PubMed1993

A transcutaneous implantable bladder controller.

We describe a computerized experimental system to investigate the effect of early electrical stimulation of the bladder during the spinal shock phase in paraplegic dogs. This system is composed of two main devices; an external part (or controller) based on a portable microcomputer, and a versatile implant (internal) based on a multichannel CMOS microstimulator. Using a new operative technique, this system enabled us to obtain many favorable results.

Animals↗
PubMed1993

Neuroendocrine profile of SDZ HDC-912 and OPC-4392, two new atypical antipsychotic drugs, in schizophrenic patients.

The aim of this study was to evaluate the effect on the activity of the hypothalamic-pituitary dopaminergic system of two new atypical antipsychotic drugs: the ergoline derivative SDZ HDC-912, which is a dopamine (DA) D2 receptor partial agonist; and the quinolinone derivative OPC-4392, which acts as an agonist at presynaptic DA autoreceptors and as an antagonist at post-synaptic D2 receptors. The effects of both compounds were compared to the effects of the benzamide derivative amisulpride. Prolactin (PRL) and growth hormone (GH) levels before and after challenge with apomorphine (Apo), a dopaminergic agonist, were determined after at least 2 weeks washout and again after 1 month of treatment in DSM-III-R schizophrenic inpatients. SDZ HDC-912 significantly decreased Apo-induced PRL inhibition, and tended to decrease PRL secretion and Apo-induced GH stimulation. OPC-4392 induced a significant decrease in baseline PRL and in Apo-induced PRL suppression, and a non-significant decrease in Apo-induced GH stimulation. The neuroendocrine profiles of these two compounds agree with their dopaminergic properties; however, the decrease in PRL basal level differentiates the two drugs from neuroleptic agents.

Adult↗
PubMed1993

[In vitro pharmacological study of fluconazole. Evaluation of an antifungal assay].

Fluconazole is a new antifungal drug which is now very often used for the treatment of yeasts infections: mucocutaneous candidosis, systemic candidosis and cryptococcosis. Some resistance seems to occur in clinical practice. It turns out now that it must be necessary to test the drug susceptibility in vitro of the yeast strains isolated from patients. Unfortunately, a current laboratory technique to test this agent doesn't exist. In this work a useful method for Minimal inhibitory concentration (MIC) evaluation in a commercial available broth medium, and a technique for testing fluconazole disks on an agar medium are studied. 150 strains of different yeasts species are tested. A regression curve is performed to correlate the two methods.

Antifungal Agents↗
PubMed1992

Effect of early bladder stimulation on spinal shock: experimental approach.

The period of spinal shock which frequently follows spinal cord injury is associated with bladder areflexia and urinary retention. We studied the effect of early bladder electric stimulation on detrusor activity during the spinal shock phase in the dog. The animals had a spinal cord section at T10 vertebra, and their bladder management was assigned to one of the three following groups: intermittent catheterization, indwelling catheterization, and electric bladder stimulation. The parameters for evaluating each treatment included: blood chemistry, and radiographic and urodynamic tests. The most important finding was the early return of detrusor activity in the group of animals treated by early electric stimulation of the bladder.

Animals↗
PubMed1992

Electrical stimulation induced sphincter fatigue during voiding.

The stimulation of the sacral nerves to induce voiding is often associated with simultaneous contraction of the striated sphincter rendering micturition difficult or impossible. Rhizotomy of some sacral nerves was found to be necessary to facilitate voiding with stimulation. An main objective in the present experiment was to evaluate the feasibility of achieving the same result using electrical stimulation to fatigue the sphincter. In order to compare the effect of rhizotomy and fatiguing striated sphincter, the bladder outlet resistance was measured. S2 nerves were stimulated with 3 V, 35 Hz and 100 microseconds duration for 5 to 10 sec. Following S2 nerves stimulation the pudendal nerve was stimulated till we obtained sphincteric fatigue. The optimal parameter to induce sphincter fatigue were 3 V, 100-500 Hz and 100 microseconds. for 15-20 sec. The combined pressure-flow studies showed that fatiguing the sphincter via the pudendal nerve using these parameters was as good as cutting it in achieving bladder emptying with stimulation.

Animals↗
PubMed1992

Role of electric stimulation in bladder evacuation following spinal cord transection.

Neural stimulation is potentially a valuable therapeutic tool in the treatment of neurogenic bladder with detrusor areflexia. We studied 20 dogs in different groups, up to eight months, and compared the effect of electric stimulation with intermittent catheterization, specially during spinal shock phase. We found that early stimulation hastened the return of detrusor activity. When stimulation was delayed, the bladder could still regain its activity, and when the pace-maker was turned off, the detrusor activity was gradually decreased. Neurostimulation can completely empty bladder up to eight months. The lowest A.Ch. content in detrusor muscle was found in intermittent catheterization group and in this group the detrusor strips showed marked supersensitivity to urecholine stimulation than the bladders managed by electric stimulation. Also, we found that electric stimulation reduced the complications caused by intermittent catheterization and protected kidney function.

Animals↗
PubMed1992

Computerized transcutaneous control of a multichannel implantable urinary prosthesis.

In the present paper we describe a personal computer interface of a multichannel implantable urinary prosthesis. This system is composed of two main parts: the first one is internal and consists of an implant using a 4-microns CMOS gate array chip controlling a wide variety of waveforms via eight monopolar channels. The second, an external controller featuring a versatile software, a PCB card plugged in a portable microcomputer, and a radiofrequency-coupled technique. This device is used to transmit the power, the data and the synchronization clock to the implant by a simple binary signal modulating a 20 MHz carrier. We also report the features of implant encapsulation and electrode design and fabrication. In the experimental phase, we studied the effect of early electric stimulation of the bladder during the spinal shock phase in the dog. We present the operative techniques that enabled us to perform chronic electrostimulation of the sacral roots and discuss the results.

Animals↗
PubMed1992

Bio-clinical prevalence or non-prevalence of drug addiction over psychiatric symptomatology.

It has been found that opiate abusers once detoxified are afflicted with personality disorders. An attempt was made to test the origin of drug abuse by comparing a group of drug abusers with personality disorders diagnosed as borderline or schizotypal with a group of people suffering from similar personality disorders but who did not use drugs. The results of the test are discussed.

Adult↗
PubMed1992

[Unipolar-bipolar distinction. The genetic arguments].

The latest classifications of mood disorders, such as DSM III and ICD 10, differ from previous ones by emphasizing the bipolar-unipolar distinction. This fairly recent distinction now enjoys a wide consensus. It is supported mainly by family studies. The first works originated from the school of Kleist and Leonhard and were quickly followed by reports by Perris and Angst (1966). Studies that followed the publication of DSM III confirm that the prevalence of bipolar mood disorders is twice as high among first-degree relatives of bipolar probands when compared with those of unipolar probands. Family studies suggest that unipolar and bipolar disorders are distinct but still share some degree of genetic overlap. Other genetic approaches such as twin and adoption studies are less conclusive. Recent linkage studies with genomic markers (RFLPs) cannot directly support the validity of the bipolar-unipolar distinction. They suggest the role of a major gene locus, notably in the Xq27-Xq28 region, only in a limited number of bipolar pedigrees. Most mood disorders might involve a polygenic environment; in this context, a more limited number of factors could be associated with the polarity of the disorder.

Bipolar Disorder↗
PubMed1991

[Neuro-electrophysiologic studies in abstinent and depressed alcoholic patients treated with tianeptine].

A concerted study of the clinical and electrophysiologic effects of tianeptine was conducted in alcoholic patients hospitalized for 5 weeks for alcohol withdrawal cures and subsequent depression. Because of the well known manifestations of infraclinical cognition impairment, sleep disorders and greater susceptibility to undesirable effects of psychotropic drugs, which hinder health care in this type of patient, the authors investigated changes in cognitive functions and the effect of tianeptine on sleep organization and daytime vigilance. Results after 4 weeks treatment (3 times 12.5 mg/day) included: besides its antidepressant effect, tianeptine reduces the manifestations of anxiety, without sedation effects, either clinical or electrophysiologic; tianeptine has no deleterious effect on cognitive functions, on the contrary, it appears to favour recovery when they are impaired; tianeptine does not modify sleep structure, notably in paradoxal sleep; tianeptine is an antidepressant which has a good acceptability, even for a population at "risk".

Adult↗
PubMed1990

Difference between evening and morning thyrotropin responses to protirelin in major depressive episode.

We studied the thyrotropin response to protirelin challenge (200 micrograms intravenously) at 8 am and at 11 pm after a minimum washout period of 10 days in 29 euthyroid inpatients who met DSM-III-R criteria for major depressive episode and 20 normal volunteer controls. The maximum increment in thyrotropin above baseline (delta thyrotropin) was significantly greater at 11 pm than at 8 am both in patients and in controls. However, the difference between 11 pm delta thyrotropin and 8 am delta thyrotropin (delta delta thyrotropin) was significantly lower in patients than in controls. The lower delta delta thyrotropin found in patients could not be explained by differences in age, body weight, sex, or thyroid functioning. In the overall population, delta delta thyrotropin correlated with circadian variables (ie, mesor and amplitude). With the use of a criterion of less than 3 mU/L to define a blunted delta delta thyrotropin, the diagnostic sensitivity was 89% and the specificity was 95%. We suggest that delta delta thyrotropin has the advantage of taking into account chronobiologic influences in the interpretation of the protirelin/thyrotropin challenge, and this may explain the improved diagnostic value derived from this measure in the diagnosis of major depressive episode.

Adult↗
PubMed1990

Random number generation by normal, alcoholic and schizophrenic subjects.

Controls (N = 45), schizophrenics (N = 20) and alcoholics (N = 23) were asked to choose at random a number between 1 and 10, 100 times. The correlation matrices of five different randomization indices were used to study within group variation; these matrices were similar for the normal and alcoholic groups, but very different for the schizophrenic group. The differences between the three groups were studied by canonical analysis and, in terms of the canonical variables, the mean performance of the normal group is clearly discriminated from that of the alcoholic and schizophrenic subjects.

Adult↗
PubMed1989

The effect of early bladder stimulation on spinal shock: a preliminary report.

The period of spinal shock which frequently follows spinal cord injury is associated with bladder areflexia and urinary retention. We studied the effect of early bladder electric stimulation on detrusor activity during the spinal shock phase in the dog. The animals had a spinal cord section at T10 vertebra and their bladder management was assigned to one of the three following groups: intermittent catheterization, indwelling catheterization and electric bladder stimulation. The parameters for evaluating each treatment included: blood chemistry, radiographic and urodynamic tests. The salient feature was the early return of detrusor activity in the group of animals treated by early electric stimulation of the bladder.

Animals↗
PubMed1989

Influence of end-stage renal failure on concentrations of free apolipoprotein A-1 in serum.

We determined, immunoturbidimetrically, the concentrations of apolipoprotein A-I (apo A-I) (a) in total serum, (b) in total lipoproteins, and (c) in the fraction of d greater than 1.21 kg/L (free apo A-I) in 31 uremic patients (16 on hemodialysis, HD, and 15 with end-stage renal failure, ESRF) and 14 control subjects. The concentration of free apo A-I in serum was significantly increased in both groups of uremic patients (0.27 +/- 0.07 g/L for HD and 0.22 +/- 0.08 g/L for ESRF, mean +/- SD), in comparison with the control group (0.14 +/- 0.04 g/L). The ratio of total apo A-I to high-density-lipoprotein cholesterol was significantly increased in sera from both uremic groups, whereas the apo A-I/HDL-chol ratio of total lipoproteins was similar in all three groups. No apo A-I could be detected in five ultrafiltrates of plasma, even after 100-fold concentration. Analysis of apo A-I isoforms by isoelectrofocusing revealed a significant relative increase in apo A-I3 and a decrease in apo A-I5 isoform in ESRF patients, but not in HD patients. Finally, we found no relationship between serum TG and free apo A-I concentration.

Adult↗
PubMed1988

Anomalies in composition of uremic lipoproteins isolated by gradient ultracentrifugation: relative enrichment of HDL in apolipoprotein C-III at the expense of apolipoprotein A-I.

Using a discriminating gradient separation technique combined with careful analysis of lipid and apolipoprotein (apo) composition, serum lipoproteins of 20 chronically uremic patients have been compared with those of 19 normal controls matched for age and sex. In uremic subjects, serum VLDL concentration was markedly increased. These particles were enriched in protein and cholesterol and relatively poor in triglycerides (TG). They contained more frequently apo B-48, and a decreased proportion of apo E. Expressed in percent, total apo C was normal but the ratio of apo C-III2/apo C-III1 was elevated. Uremic IDL, whose serum concentration was markedly increased, were characterized by an increased proportion of protein. Total uremic LDL whose serum concentration was normal, contained less esterified cholesterol (EC) and more TG than normal LDL, their EC/TG ratio being very low. Moreover, the concentration of the mature subfraction of LDL having a mean density of 1.043 g/ml, was markedly decreased in uremic subjects. Taken together, these anomalies indicate a delayed transformation of VLDL into LDL in chronic renal failure. The decreased concentration of total HDL in uremic subjects was more marked in HDL2 (-46%) than HDL3 (-24%). Both uremic HDL2 and HDL3 were relatively enriched in TG, and uremic HDL3 were poorer in EC than normal HDL3.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗