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Biomedical subjects

M Picard

Publications and source records attributed to M Picard.

At least 91 records · Page 5Linked to original sources
PubMed1994

Olfactory cues mediate food selection by young chicks.

An illness-induced aversion paradigm was used to assess the possible influence of olfactory cues on food selection by young chicks. At 2-3 days posthatching, chicks were exposed briefly to food scented with a novel odor (orange) followed by an injection of LiCl or saline. LiCl-injected chicks subsequently displayed stronger avoidance of orange-scented food than did the controls. Chicks in a second experiment were preexposed to novel-scented food, then either injected with LiCl or not injected. The LiCl chicks, but not the controls, later avoided food associated with the preexposure odor (relative to food treated with an unfamiliar odorant). Two- to three-day-old chicks are capable of associating specific food odors with negative consequences and modify their feeding behavior as a function of such experience.

Age Factors↗
PubMed1994

Removal of residual yolk at hatch influences food choice and feeding activity in lines of chickens selected for high or low juvenile body weight.

The effect of residual yolk removal at hatch on growth and feeding behavior was assessed in lines of chickens divergently selected for low (LW) or high (HW) 56-day body weight. At hatch chicks were assigned to 1 treatment: removal of the residual yolk (R) or no surgery (I). Twenty-four chicks per line (12 I and 12 R) were assigned to an all-mash regimen (M) and 48 per line (24 I and 24 R) to a choice (C) between mash and dietary residual yolk. HW were heavier than LW chicks regardless of treatment. On day 5 and thereafter, chicks given a choice were heavier than those eating mash. HW chicks ate more than LW ones. The percentage of yolk eaten increased during the 2-3 d after hatch, remained constant for 2 d, then decreased. Results are discussed in term of yolk need and development of the gastrointestinal tract in the divergent lines.

Animal Feed↗
PubMed1994

Synthesis of heat-shock proteins in mycelia and yeast forms of Paracoccidioides brasiliensis.

The induction of heat-shock proteins has been postulated to play a role not only in thermo-adaptation, but also in phase transition of the dimorphic fungi. In this study, we used yeast and mycelial forms of the thermally dimorphic fungus Paracoccidioides brasiliensis to evaluate the effect of temperature on the induction of the heat-shock response. We also evaluated protein synthesis by P. brasiliensis caused by exposure to low pH and H2O2. Analysis of protein synthesis by SDS-PAGE disclosed that P. brasiliensis mycelia increased synthesis of all major constitutive proteins when stressed at 37 degrees C and increased synthesis of three non-constitutive proteins of 134, 82 and 28 kDa at 40 degrees C. Yeasts incubated at 40 degrees C showed decreased synthesis of five constitutive proteins (136, 98, 62, 57 and 54 kDa) and the appearance of three new proteins (134, 82 and 28 kDa). There was a decrease in the synthesis of all major constitutive proteins except for three proteins of 141, 136 and 16 kDa when yeast cells were incubated at 25 degrees C. When stressed by low pH and H2O2, P. brasiliensis yeast increased synthesis of one (134 kDa) and five (134, 104, 82, 52 and 40 kDa) non-constitutive proteins, respectively. P. brasiliensis mycelia and yeast forms disclosed the same profile of protein synthesis when stressed at temperatures that trigger phase transition (37 degrees C for mycelia; 25 degrees C for yeast).(ABSTRACT TRUNCATED AT 250 WORDS)

Autoradiography↗
PubMed1994

Pharmacokinetic study of rifaximin after oral administration in healthy volunteers.

Eighteen healthy male volunteers, with a mean age of 24 yrs (range 18-40), underwent an open pharmacokinetics study, aimed at detecting rifaximin concentration in blood and urine after a single oral administration of 400 mg of the antibiotic. Administration took place after a 9 hours' fast and was followed by a breakfast after 2 hours and a lunch after 5 hours. Blood samples were collected before rifaximin administration and 1, 2, 4, 8, 12, 24 and 48 hours after dosing. Urine samples were collected immediately before dosing (reference sample) and then at the end of the following intervals of time: 0-6 h, 6-12 h, 12-24 h, 24-48 h. During the whole study period, the local and general tolerance to rifaximin administration was checked. Rifaximin concentration was assessed by reversed phase high performance liquid chromatography with electrochemical detection. In almost every plasma sample, rifaximin concentration was undetectable (lower than the detection limit of the analytical method, i.e. 2 ng/ml). In urine, very small amounts of the unchanged molecule (< 0.01% of the administered dose) were found in the period 0-48 hours. These results confirm the negligible absorption by the intestinal tract of a single oral dose of rifaximin (400 mg). Local and general tolerance of the administered drug was very good.

Administration, Oral↗
PubMed1994

Effect of yolk sac removal at hatch on growth and feeding behavior in lines of chickens differing in body weight.

Influence of residual yolk on growth, feeding behavior, and development of certain internal organs during the first week after hatch were measured in lines of chickens that had undergone long-term selection for high (HW) or low (LW) 56-day body weight. At hatch chicks were assigned to one of the following treatments: removal of residual yolk (Y), sham operated (S), or no surgery (I). Body weight gains of HW chicks began on day 1 while LW chicks did not begin to gain weight until several days after hatch. Food intake increased linearly in both lines, but at a higher rate for HW than LW chicks. Seven days after hatch, relative to body weight, shanks were longer and pancreases and small intestines heavier for HW than LW chicks. Among treatments, body weight gains were greater for I and S than for Y chicks in the HW line, but not the LW line, demonstrating a differential response by fast and slow growing chicks to removal of the yolk sac. Feed intake differed on day 3, with Y chicks eating less than S chicks; I chicks were intermediate. Results indicate that presence of residual yolk sac during the first three days after hatch are critical to growth and development of chicks.

Animals↗
PubMed1994

Prognostic implications of transient left ventricular cavitary dilation during exercise and dipyridamole-thallium imaging.

OBJECTIVE: To determine the prognostic implication of exercise and dipyridamole-induced transient left ventricular cavitary dilation (TLVD). DESIGN: TLVD was observed and a follow-up obtained in 61 patients after exercise and in 62 patients following dipyridamole infusion. PATIENTS: There was no statistical difference between groups in terms of sex, history of hypertension, diabetes, renal failure, previous myocardial infarction, severity of angina syndrome, congestive heart failure, resting electrocardiographic (ECG) abnormalities, clinical or ECG signs of ischemia during stress, number of reversible perfusion defects on thallium images or duration of follow-up (21 months). RESULTS: Dipyridamole patients were slightly older (64 versus 57 years) and displayed more thallium redistribution (P = 0.002). After a mean follow-up of 21 months, both fatal and nonfatal (myocardial infarction or cardiac death) cardiac events were more frequent in the dipyridamole group (50% versus 9%, P = 0.0001). CONCLUSIONS: Patients with dipyridamole-induced TLVD are at greater risk than those with exercise-induced TLVD at the authors' institution.

Aged↗
PubMed1993

Complications and survival of multilumen central venous catheters used for total parenteral nutrition.

In a prospective study of 879 triple-lumen catheters, 219 pulmonary artery catheters, 31 double-lumen and six single-lumen catheters used for the administration of total parenteral nutrition over a 1-year period, the overall complication rate was 12.5 per cent (14.7 complications per 1000 catheter-days) and the catheter-related sepsis rate 4.4 per cent (5.2 per 1000 catheter-days). The probability of development of catheter-related sepsis did not increase with the duration of catheterization. There were no differences in the rate of complications associated with 427 catheters changed by replacement at a new site compared with 159 lines changed over a guidewire. These data support the use of multilumen central venous catheters for the administration of total parenteral nutrition. They suggest that a routine weekly change of line is unnecessary; catheters should be changed only on the development of a complication. When it is required, a catheter should be changed by replacement over a guidewire.

Bacterial Infections↗
PubMed1993

Deletion of the mating-type sequences in Podospora anserina abolishes mating without affecting vegetative functions and sexual differentiation.

The mating-type locus of Podospora anserina controls fusion of sexual cells as well as subsequent stages of development of the fruiting bodies. The two alleles at the locus are defined by specific DNA regions comprising 3.8 kb for mat+ and 4.7 kb for mat-, which have identical flanking sequences. Here we present the characterization of several mutants that have lost mat(+)-specific sequences. One mutant was obtained fortuitously and the other two were constructed by gene replacement. The mutants are deficient in mating with strains of either mat genotype but are still able to differentiate sexual reproductive structures. The loss of the mating type does not lead to any discernible phenotype during vegetative growth: in particular it does not change the life span of the strain. The mutants can recover mating ability if they are transformed with DNA containing the complete mat+ or mat- information. The transformants behave in crosses as do the reference mat+ or mat- strains, thus indicating that the transgenic mat+ and mat- are fully functional even when they have integrated at ectopic sites.

Alleles↗
PubMed1993

Ga-67 imaging in primary and secondary psoas abscess.

Primary and secondary psoas abscesses are uncommon and frequently misdiagnosed. Two cases of pyogenic psoas abscess are presented to illustrate the usefulness of Ga-67 scintigraphy in determining the presence and the extent of the infectious process.

Adolescent↗
PubMed1993

Tc-99m sestamibi and other agents in the detection of metastatic medullary carcinoma of the thyroid.

The 10-year survival rate for medullary carcinoma of the thyroid (MCT) is 50%; thus, good tumor-seeking radiopharmaceuticals are needed to localize foci of recurrence and metastasis during follow-up. Two patients with metastatic MCT were studied with Tl-201, I-131 MIBG, Tc-99m (V)-DMSA, and Tc-99m MIBI. A SPECT study with the latter agent allowed the visualization and precise localization of a metastatic mediastinal lymph node. More studies need to be done to evaluate the role of Tc-99m MIBI in the detection of recurrence and metastases of MCT.

Adult↗
PubMed1993

Clinical use of BOBCAT: testing reliability and validity of computerized pure-tone audiometry with noise-exposed workers, children and the aged.

An investigation was conducted to determine the feasibility of implementing computerized audiometry in various clinical groups, using the Battery of Basic Computerized Audiometry Tests (BOBCAT). Reliability, validity and speed of execution were assessed as a function of hearing loss in a group of noise-exposed workers. Children and the aged were also included to represent potentially 'more-difficult-to-test' patients due to fluctuating attention, motivation and/or response behavior. Children were aged 7.5-12 years; seniors, 65-80 years. Reliability was assessed by calculating reliability coefficients between air conduction pure-tone thresholds (0.5, 1, 2, 3, 4 and 6 kHz) obtained under two test modalities namely, computerized audiometry and conventional testing performed by a small panel of trained examiners. Both procedures followed ANSI S3.21 1978 standards. Content validity was measured using measures of central tendency and correlations. Coefficients of reliability remained equally high across frequencies regardless of degree of hearing loss and group. As well, group means and correlations between conventional and computerized audiometry indicated that the two methods measured pure-tone hearing sensitivity with the same degree of accuracy; that is, within +/- 0.5 dB. Finally, speed of execution was found to be slower using BOBCAT, in particular with noise-exposed workers. This finding was interpreted as evidence that trained examiners have used shortcuts when they expect consistent and/or unbiased response behavior.

Acoustic Impedance Tests↗
PubMed1993

Feed intake adjustments by hens to feeding regimens in which dietary methionine is varied.

At 20 wk of age, 315 ISA Brown pullets were individually caged and randomly assigned to one of seven feeding regimens for the next 20 wk. In Regimen 1 Diet A was fed, in Regimen 2 Diet B was fed, Regimens 3 and 4 alternated Diets A and B weekly (the week Diet A was fed in Regimen 3, Diet B was fed in Regimen 4), Regimens 5 and 6 alternated Diets A and B monthly (reversing as with 3 and 4), and in Regimen 7 pullets were given a choice of Diets A and B. Diet A was methionine-deficient (.23%) and Diet B was balanced for methionine (.33%). Feed and nutrient consumption, egg production, egg weight, and egg mass were lower in Regimen 1 than 2. Pullets in Regimen 1 lost body weight and those in Regimen 2 gained weight. Overall feed consumption for Regimens 3 through 7 was similar to that for Regimen 2. For Regimens 3 through 6, however, consumption increased when the balanced diet was fed and decreased when the deficient diet was fed. Concomitant with these oscillations in feed consumption were changes in egg mass, so that means for these traits were intermediate and different from those for Regimens 1 and 2. For Regimen 7, in which Diets A and B were continuously available, no preference of diet was observed during the first 4 wk.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗
PubMed1992

Preoperative coronary artery disease risk stratification based on dipyridamole imaging and a simple three-step, three-segment model for patients undergoing noncardiac vascular surgery or major general surgery.

A 3-step, 3-segment scintigraphic model was developed to improve the accuracy of dipyridamole-thallium imaging for preoperative cardiac risk assessment and to simplify the prognostic interpretation of the images. The model was developed in a pilot study of 60 patients and validated in a group of 355 patients referred for vascular and major general surgery. Study end points included myocardial infarction and cardiac death. Step 1: The postoperative cardiac event rate was 1.3% in 225 patients with normal anterior, inferio- and posterolateral segment perfusion and without transient left ventricular dipyridamole-induced cavitary dilation. Step 2: The physiologic rationale for step 2 consists of identifying patients who are most likely to have left main, 3-vessel or high-risk 2-vessel coronary artery disease or a significant amount of jeopardized myocardium in the territory of a critical coronary stenosis. Of 29 patients with either reversible defects of all 3 segments, transient cavitary dilation, or at least 1 severe grade 3/3 reversible defect, 52% (15 of 29) sustained a postoperative cardiac event. Step 3: The remaining 101 patients were stratified according to age greater than 70 years (p = 0.01), presence of diabetes (p = 0.0004) and the number of segments displaying reversible defects (1 or 2) with cardiac event rates ranging from 5 to 36%. The 3-step, 3-segment model is a useful alternative to the conventional interpretation of dipyridamole myocardial perfusion images for the purpose of quick and efficient preoperative risk stratification based on the rationale of correlating surgical risk with the amount of potentially ischemic myocardium.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1992

Prognostic implications of a negative dipyridamole-thallium scan: results in 360 patients.

PATIENTS AND METHODS: A total of 360 patients with either normal perfusion (314) or fixed defects (46) on dipyridamole-thallium scans were followed over an average period of 16 months. Of the 360 patients, 194 subsequently underwent major noncardiac surgery. RESULTS: There were a total of eight cardiac events including two postoperative complications (one fatal and one nonfatal myocardial infarction) and six cardiac events during long-term follow-up (one sudden death and five nonfatal infarctions). During the follow-up period, three patients underwent coronary artery bypass surgery. The low cardiac event rate could not be explained by a low pretest likelihood of coronary artery disease: 77% of the 360 patients had either typical angina pectoris, a previous myocardial infarction, or peripheral vascular disease, which is associated with a high prevalence of coronary artery disease. CONCLUSIONS: In patients with a high pretest likelihood of coronary artery disease, the absence of thallium redistribution on a dipyridamole-thallium scan denotes a very low (1%) cardiac risk for major noncardiac surgery as well as low long-term cardiac mortality (0.3%) and morbidity (1.4%) rates. The coronary death rate is comparable to that of patients with minimal (less than 50%) coronary stenoses.

Clinical Protocols↗
PubMed1992

Feeding behavior in rats on a complete diet containing Concanavalin A.

Canavalia ensiformis is a tropical legume which could be used in animal feeding. However, it contains a lectin, Concanavalin A (Con A) which is harmful to animals. When rats are presented with a diet containing Con A, rejection of the food appears very soon after the beginning of ingestion. In order to examine this rejection phenomenon 3 studies were carried out. The rejection was found not to be due to a neophobic response, nor could it be attributed to a conditioned taste aversion. The gastric intubation study suggested the hypothesis that it could be the binding of the lectin to the glycosylated molecules from the gut membrane which impaired absorption and hence food intake.

Animals↗
PubMed1992

Preoperative and long-term cardiac risk assessment. Predictive value of 23 clinical descriptors, 7 multivariate scoring systems, and quantitative dipyridamole imaging in 360 patients.

A total of 360 patients underwent preoperative cardiac risk assessment using 23 clinical parameters, seven multivariate clinical scoring systems, and quantitative dipyridamole-thallium imaging to predict postoperative and long-term myocardial infarction and cardiac death after noncardiac surgery. There were 30 postoperative and an additional 13 cumulative long-term cardiac events after an average follow-up of 15 months. Clinical descriptors were not useful in predicting the outcome of individual patients. The postoperative and long-term cardiac event rates were 1% and 3.5%, respectively, in patients with normal scans or fixed perfusion defects, and 17.5% and 22% in patients with reversible defects. Using quantitative indices reflecting the amount of jeopardized myocardium, patients could be stratified by dipyridamole imaging into multiple scintigraphic subsets, with corresponding postoperative and 1-year coronary morbidity and mortality rates ranging from 0.5% to 100% (p = 0.0001). Thus, postoperative and long-term cardiac events cannot be predicted clinically, whereas quantitative dipyridamole imaging accurately identifies high-risk patients who require preoperative coronary angiography.

Aged↗