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Biomedical subjects

M Picard

Publications and source records attributed to M Picard.

At least 127 records · Page 7Linked to original sources
PubMed1990

Extrahepatic uptake of technetium-99m-phytate: a prognostic index in patients with cirrhosis.

We examined the usefulness of technetium-99m-phytate (99mTc-phytate) hepatic scintigraphy in the evaluation of hepatic function, and the assessment of prognosis in patients with cirrhosis. Ninety-four patients with biopsy-documented cirrhosis had, at the time of entry into the study, a scintigraphy with 99mTc-phytate complexed with calcium in vivo. Extrahepatic uptake (EHU) of 99mTc-phytate on scintigraphy was graded from 0 (absent EHU) to 5 (important EHU) according to the relative distribution of the radiotracer between the liver, the spleen and the bone marrow. The severity of liver disease was also assessed according to the index of Child and Turcotte as modified by Pugh et al. Mean follow-up was 2 yr. EHU was correlated to the Pugh score (r = 0.73) and to survival. Survival at 2 yr was 97% for an EHU equal or inferior to 2.5, 62% for grades 3-4.5, and 31% for grade 5. In conclusion, hepatic imaging with 99mTc-phytate, in addition to its diagnostic value, also contains valuable prognostic information in patients with cirrhosis.

Bone Marrow↗
PubMed1989

Determination of exifone in human plasma and urine by high-performance liquid chromatography with electrochemical detection.

A high-performance liquid chromatographic method with electrochemical detection was developed for the determination of exifone in human plasma and urine. Exifone was extracted from acidified plasma or neutralized urine with diethyl ether and the evaporated extracts were analysed on a C18 reversed-phase column. The compound was eluted in about 8 min with acetonitrile-0.3 M orthophosphoric acid (15:85, v/v) at a flow-rate of 0.9 ml/min. This method gave accurate and reproducible results; the calibration graphs were linear (r greater than 0.99) over the range of 2.8-360 nmol/l for plasma and 0.18-36 mumol/l for urine, and concentrations as low as 1 nmol/l in plasma could be quantified. These results allowed this assay to be used for determinations in single-dose pharmacokinetic studies.

Benzophenones↗
PubMed1989

Usefulness of the severity and extent of reversible perfusion defects during thallium-dipyridamole imaging for cardiac risk assessment before noncardiac surgery.

Thallium-dipyridamole imaging is a very sensitive test for predicting cardiac events after noncardiac surgery, but it lacks specificity. To improve specificity, a semiquantitative scoring system was developed that combined dipyridamole-induced reversible left ventricular dilatation with scintigraphic indexes for severity and extent of reversible perfusion defects. Using this scoring system, patients were classified into low, intermediate and high risk subgroups. Thallium-dipyridamole imaging was performed in 66 patients before major general and vascular surgery. Thirty-nine patients classified as low risk (30 with normal scans and 9 with fixed defects) underwent surgery uneventfully. Surgery was cancelled in 6 patients with extensive thallium redistribution and coronary angiography was performed because of severe coronary artery disease in 5 and idiopathic dilated cardiomyopathy in 1. In the remaining 21 patients with thallium redistribution, a positive statistical correlation (p = 0.001) between scintigraphic indexes of severity and extent, and cardiac events was noted. Using cutoff values for the scintigraphic indexes, patients with reversible defects could be classified into intermediate and high risk subgroups. Only 1 of 11 patients at intermediate risk developed a complication, whereas 8 of 10 patients at high risk had a postoperative event (7 deaths and 1 myocardial infarction). Thus, using scintigraphic indexes for severity and extent, patients with reversible defects can be stratified into an intermediate risk subgroup that can safely undergo surgery and a high risk subgroup that requires coronary angiography.

Angiography↗
PubMed1989

Transformation by integration in Podospora anserina. III. Replacement of a chromosome segment by a two-step process.

We have developed in Podospora anserina a two-step procedure for DNA sequence replacement through transformation which might be applicable to other filamentous fungi. Targeting of transforming DNAs to their homologous locus is achieved provided a cosmid vector is used. Southern blot analysis of genomic DNAs from a set of transformants is presented. The data confirm that cosmids integrate into the chromosome through mostly homologous recombination which leads to a duplicated sequence separated by the vector. This event was found to be unstable in crosses. We show that this instability is due to the frequent excision of the vector together with the selective marker and one copy of the duplication, either the resident or foreign sequence. The two sequences can be distinguished because they exhibit restriction fragment length polymorphism. Therefore, Podospora anserina treats duplications occurring through transformation in a way differing from that exhibited by Neurospora crassa and Ascobolus immersus.

Ascomycota↗
PubMed1989

Technetium-99m ECD: a new brain imaging agent: in vivo kinetics and biodistribution studies in normal human subjects.

Lipophilic neutral 99mTc complexes of diaminedithiol (DADT) ligands cross the brain-blood barrier. A new derivative of DADT family, 99mTc ethyl cysteinate dimer (ECD) showed high brain uptake in nonhuman primates. We report here the in vivo kinetics and biodistribution results in 16 normal human subjects. Dynamic images of brain obtained for 10 min following an i.v. administration of [99mTc]ECD showed that the maximum 99mTc brain activity reached within 1 min and remained near that level for the next 10 min. The blood clearance of the tracer was very rapid and the activity remaining in blood after 5 min was less than 10%. Within 2 hr 50% of 99mTc activity was excreted in urine. Anterior and posterior total-body images were obtained at 5, 30, 60 min, 2, 4, 24, and 48 hr using a moving table at 20 cm/min. Percent injected dose was calculated for different organs and tissues. The brain uptake was 6.5 +/- 1.9% at 5 min postinjection and remained relatively constant over several hours. Two-compartment analysis of brain time-activity curve showed that 40% of brain activity washed out faster (T 1/2 = 1.3 hr) while the remaining 60% had a slower clearance rate (T 1/2 = 42.3 hr). Some of the tracer was excreted through the hepatobiliary system. Lung uptake and retention of [99mTc]ECD was negligible. Radiation dosimetry is favorable for the administration of up to 20-40 mCi of [99mTc]ECD. These results show that [99mTc]ECD is rapidly extracted and retained by the brain providing favorable conditions for single photon emission computed tomography imaging.

Adult↗
PubMed1989

Technetium-99m hexakis 2-methoxyisobutyl isonitrile: human biodistribution, dosimetry, safety, and preliminary comparison to thallium-201 for myocardial perfusion imaging.

The biodistribution, dosimetry, and safety of a new myocardial imaging agent, 99mTc-hexakis-2-methoxyisobutyl isonitrile (HEXAMIBI), was evaluated in 17 normal volunteers at rest and exercise (Phase I studies). Technetium-99m HEXAMIBI clears rapidly from the blood with good myocardial uptake and favorable myocardial-to-background ratios for myocardial imaging. Dosimetry allows for administration of up to 30 mCi (1, 110 Bq) of [99mTc]HEXAMIBI. The myocardial images were of good quality and appeared less granular with sharper myocardial walls compared to 201T1 images. The clinical efficacy of [99mTc]HEXAMIBI planar stress and rest imaging was evaluated in a multicenter Phase II clinical trial involving 38 patients. Of 36 patients with significant coronary artery disease, 35 patients (97%) had abnormal 201T1 stress images, and 32 (89%) had abnormal [99mTc]HEXAMIBI stress images (P = N.S.). Technetium-99m HEXAMIBI images correlated in 31/35 patients (86%) who had either scar or ischemia on 201T1 images. By segmental myocardial analysis, exact concordance was obtained in 463/570 myocardial segments (81%). This multicenter Phase I and II study indicates that planar [99mTc]HEXAMIBI stress imaging is safe and compares well with 201T1 stress imaging for detection of coronary artery disease.

Adult↗
PubMed1988

Myocardial perfusion imaging with 99mTc-methoxy-isobutyl-isonitrile (MIBI): comparison of short and long time intervals between rest and stress injections. Preliminary results.

Unlike 201Tl, 99mTc-methoxy-isobutyl-isonitrile (99mTc-MIBI) does not redistribute in the myocardium after injection. Thus, two separate injections of this new myocardial perfusion agent are required to differentiate ischemia from scar. An injection at stress followed by a 2nd injection at rest performed 24 h later, or the inverse, has been proposed. This protocol is not ideal in clinical practice. It would be preferred if both injections were performed on the same day. Fifteen patients with significant coronary artery disease demonstrated by coronary angiography and with at least one ischemic segment on the myocardial 201Tl study were evaluated within two weeks with the following protocol. On the same day (short time interval protocol), 3 images, each of 10 min duration (anterior, 45 degrees LAO and 70 degrees LAO views) were performed between 30 to 60 min after the injection at rest of 7-10 mCi 99mTc-MIBI. On completion of the rest study, the patient received 25-30 mCi 99mTc-MIBI at stress and images were again obtained 30 to 60 min later. Two days later (long time interval protocol) a stress study alone was repeated using 10 mCi 99mTc-MIBI with the same imaging time. Qualitative and quantitative comparisons between the short and the long time interval studies were performed by four experienced observers. Both protocols showed the same number of ischemic segments (52/225) and fixed defects (19/225). The diagnostic information of images was judged similar in nine patients while the short protocol was judged superior to the long protocol in five patients and inferior in 1.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

[Diagnosis of rabies by cell culture].

Mouse inoculation test (MIT) is a highly sensitive test for rabies diagnosis but slow and expensive. To detect rabies virus an in vitro technique using Neuro 2a cell culture (CC) was compared with MIT in two laboratories. In one laboratory, CC appeared to be on the whole more sensitive than MIT, nevertheless MIT was the only one to detect some positive samples. In the other laboratory, MIT was more sensitive. These results justify the use of CC for epidemiological diagnosis but emphasize the interest of MIT (the reference technique) for special cases.

Animals↗
PubMed1988

Experimental blastomycosis pneumonia in mice by infection with conidia.

We describe a murine model of acute blastomycosis pneumonia induced by Blastomyces dermatitidis conidia. Anesthetized mice were infected by placing a droplet containing conidia suspended in sterile saline on the nares and allowing the suspension to be aspirated into the lungs. Conidia were obtained from mycelia derived from the yeast forms of two well characterized strains of B. dermatitidis, ATCC 26199 and 26197. ATCC 26199 yeast and conidia were highly virulent in BALB/cByJ mice whereas both forms of ATCC 26197 were incapable of causing disease in 60 days. Conidia and yeasts of the virulent strain caused pathologic changes primarily in the lungs, whereas no abnormalities were seen in the lungs, or elsewhere, in mice infected with the a virulent strain. Small numbers of ATCC 26199 yeast forms were found in scattered foci in liver and kidneys, but no inflammatory reaction surrounded the fungus. This murine model of acute blastomycosis pneumonia mimics the acute disease in humans and is initiated with the naturally infectious particle.

Animals↗
PubMed1988

Spinal cerebrospinal fluid leak demonstrated by radioisotopic cisternography.

Many conditions are known to cause a cerebrospinal fluid (CSF) fistula; one of them is lumbar puncture for contrast myelography. Reported here is the case of a man who underwent contrast myelography at the L2-L3 level and who presented with postural headaches and lumbalgia with radiation to the legs three weeks after the procedure. Tc-99m albumin isotopic cisternography at the L5-S1 level was performed and clearly depicted a functional CSF leak through the dura at the L2-L3 level and CSF suffusion along several rachidian roots. Scinticisternography may thus be used to localize accurately a CSF leak.

Adult↗
PubMed1988

Treatment of rabies in mice and foxes with antiviral compounds.

Thirty four chemical compounds were injected into rabies infected mice by intramuscular (i.m.) route. Twenty four compounds such as well known therapeutic agents: amantadine, lipacids, phenol compounds, didemnin-B, procaine, nucleosides analogues (ribavirin, tiazofurin, pyrazofurin) had no effect. Two compounds had a slight effect not justifying to consider them as possible therapeutic agents: selenazofurin and an analogue of ribavirin (RTA). Eight heteropolyanions (HPA), which have a related chemical structure, were efficient providing 100% protection. Nineteen compounds were injected into rabies infected mice by the intracerebral (i.c.) route. Fourteen compounds such as ribavirin, RTA, selenazofurin, tiazofurin and 9 HPA compounds had no effect. Five other HPA compounds (HPA 23-39-46-51-56) were efficient preventing the development of clinical infection in some mice. Whatever was the treatment route, treated surviving mice developed rabies neutralizing antibodies. No proof of viral multiplication was found in their brains. As some HPA compounds did produce a therapeutic effect in mice, two of them HPA 23 and HPA 39 were administered to rabies-infected foxes. In foxes the compounds prolonged the mean survival time and increased the number of survivors. These data suggest that chemotherapy might be worthwhile when vaccination was impossible.

Animals↗
PubMed1988

[Clinical trial of BOBCAT: 1st report on the reliability and validity of computerized pure-tone audiometry].

Computerized diagnostic audiometry is quickly emerging as a viable productivity tool in the audiology clinic. To date, there has been little reported on its reliability and validity with the hearing-impaired. The 'Battery of Basic Computerized Audiometric Tests' (BOBCAT) is a computer program which puts a wide variety of clinical hearing tests under computer control. The purpose of the present study was to ascertain the reliability and validity of BOBCAT in the measurement of hearing sensitivity. A field study was conducted in a group of 92 workers exposed to noise to measure air- and bone-conduction thresholds. Coefficients of reliability of 0.85 and higher were obtained between air and bone thresholds for both methods of testing; that is, manual and computer-controlled audiometry. The same measurement between manual and computerized air-conduction pure-tone thresholds gave values ranging from 0.93 to 0.98. A principal-components analysis documented content validity of computerized audiometry. These results are interpreted as clear evidence of both reliability and validity of the BOBCAT procedure, with one exception: 6.7% of all observations are showing air-conduction computerized thresholds of -10 dB at one or more frequencies, with no confirmation by manual audiometry. This is attributed to insufficient randomization of intervals between stimuli, a problem which should be taken care of by new versions of the software.

Adult↗
PubMed1987

Budd-Chiari syndrome: typical and atypical scintigraphic aspects.

Budd-Chiari syndrome, a well known entity, is often difficult to diagnose, mostly due to the nonspecificity of its symptomatology. Radiocolloid liver scans were evaluated in eight cases of this disease, proven by surgical biopsy. Five cases showed the "classic" scintigraphic pattern of caudate lobe hypertrophy (62.5%), and other abnormalities observed included segmental hepatic insufficiency, diffuse hepatic insufficiency, and relative hypertrophy of both the caudate lobe and a portion of the parenchyma of segment VI (one case each). An experimental study of hepatic venous drainage performed on livers at autopsy revealed four groups of accessory hepatic veins in addition to the main hepatic veins. The occlusion of various parts of this drainage appears to relate to the various scintigraphic patterns that were encountered in patients with Budd-Chiari syndrome. A review of the literature revealed three additional patterns previously reported in association with Budd-Chiari syndrome (normal scan, diffuse hepatomegaly, and multiple filling defects). If all these variations are appreciated, liver scanning can be a valuable screening tool for Budd-Chiari syndrome and may also serve as a noninvasive means of follow-up.

Budd-Chiari Syndrome↗
PubMed1986

Changes in the serotonergic, noradrenergic and dopaminergic levels in the brain of scrapie-infected rats.

Levels of serotonin (5-HT), 5-hydroxyindoleacetic acid (5-HIAA), dihydroxyphenylacetic acid (DOPAC) and 3,4-dihydroxyphenylethyleneglycol (DHPG) were determined by high-performance liquid chromatography in different brain areas of scrapie-infected rats, 8.5 months after intracerebral inoculation of a rat-adapted strain from mice brain (C 506). At this time, rats developed early clinical signs of the disease. Scrapie-infected rats showed a reduction in the levels of 5-HT and 5-HIAA (frontal cortex, hippocampus, mesolimbic structure). Concentrations of DHPG decreased in the frontal and parietal cortices but remained unchanged in the hippocampus. DOPAC levels decreased in the striatum but not in the mesolimbic structure. These results confirm that the serotonergic, noradrenergic and dopaminergic systems are altered in the brain of scrapie-infected rats. They can partly account for clinical signs of scrapie and are in agreement with the scarce data provided by the postmortem analysis of Creutzfeldt-Jakob disease brains.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1986

Speech perception through FM auditory trainers in noise and reverberation.

Speech perception through FM auditory trainers was explored in conditions of noise and reverberation. Special attention was paid to the mode of transmission and individual capabilities of various commercially-available units to handle speech in noise and reverberation. Results indicate an overwhelming advantage of FM transmission for maintaining speech intelligibility in noise and reverberation, irrespective of the instrument.

Acoustic Stimulation↗