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Biomedical subjects

F Lucas

Publications and source records attributed to F Lucas.

53 records · Page 3Linked to original sources
PubMed1984

Deprivation, palatability and the micro-structure of meals in human subjects.

Changes in the micro-structure of meals were studied in ten human subjects under different palatability and deprivation conditions. The oscillographic recording of chewing and swallowing movements during standardized meals allowed many meal parameters to be precisely measured. Both increases in deprivation time (from 4 to 15 h) and in food preference produce larger, longer meals. These factor's effects were additive. Eating rate was accelerated in high relative to low preference conditions. The micro-structure of meals proved to be more sensitive to food preferences than to deprivation levels: chewing activity per standard food piece tended to decrease as preference increased, as observed in a previous study. However, in the first quarter of meals, chewing time was affected similarly by deprivation and by preference. A clear deceleration of eating rate was apparent between the beginning and the end of meals. The results are discussed in perspective with other human studies and with reference to preference and deprivation as continua.

Adult↗
PubMed1975

[The contribution of sulpiride to ketamine anesthesia].

The authors think that it can be asserted that Sulpiride protects the patient from neuropsychic effects of Ketamine in an almost complete manner, and this without prolonging the sleeping time, or depressing circulation or respiration.

Adult↗
PubMed1969

Mass-spectrometric determination of the amino acid sequences in peptides isolated from the protein silk fibroin of Bombyx mori.

Several peptides were isolated from the protein silk fibroin of Bombyx mori by means of ion-exchange chromatography of a chymotryptic digest. The sequences of three of the peptides, Gly-Ala-Gly-Tyr, Gly-Val-Gly-Tyr and Gly-Ala-Gly-Ala-Gly-Ala-Gly-Tyr, were known from previous chemical work, but the sequence of the fourth, Gly-Ala-Gly-Val-Gly-Ala-Gly-Tyr, was previously only partially known. The necessary volatility for mass-spectrometric examination of the peptides was achieved by permethylation of the N-acetyl-peptide methyl ester derivatives. From the mass spectra it was possible to confirm the known sequences and to establish that of the partially known one. In one instance it was possible to deduce from the same mass spectrum the sequence of a main peptide component and that of a small amount of contaminating peptide. These results demonstrate for the first time the use of mass spectrometry in the determination of the amino acid sequences in peptides from a protein hydrolysate.

Amino Acid Sequence↗
PubMed1966

The isolation of L(+)-methionine sulphoxide from the blowfly Phormia regina Meigen.

1. l(+)-Methionine sulphoxide has been isolated for the first time from a natural source, the blowfly Phormia regina. 2. The natural compound is shown to be identical with the synthetic by a number of criteria, including optical rotatory dispersion and infrared spectrum. 3. The methionine sulphoxide occurs in only a small concentration in the late larval and early pupal stages of the blowfly, but the titre increases rapidly in the later pupal stage and remains at a high level during the adult stage.

Autoanalysis↗
PubMedDate not supplied

Progression of the renal graft: treatment of acute rejection based on a biopsy against a presumptive diagnosis.

The aim of this study was to compare the progression of renal grafts following treatment of an acute rejection event based on the histological diagnosis of a graft biopsy compared to a presumptive (clinical and laboratory) diagnosis. A historical cohort was used to study 44 patients undergoing a living haploidentical related donor renal transplant, using a similar immunosuppressive treatment: cyclosporine, azathioprine, and prednisone. Acute rejection events were treated with methylprednisolone (250 mg for 3 to 5 days) based on a histological diagnosis (biopsy group = 14) or on a clinical and laboratory diagnosis (presumptive group = 30), which consisted of an elevation over 20% in plasma creatinine in 24 hours and renal ultrasound or scintigraphy findings. The study demonstrated no significant difference in renal function (plasma creatinine) and other outcomes 2 years following transplantation in both groups. The results show that treatment of acute rejection based on a presumptive diagnosis is not a risk factor for unfavorable outcomes following 2 years of renal transplantation monitoring.

Acute Disease↗
PubMedDate not supplied

Treatment of acute focal cerebral ischemia with prostacyclin.

The object of this investigation was to study the effects of prostacyclin (PGI2) upon the evolution of acute focal cerebral ischemia in the cat. Twenty-five fasted adult cats, lightly anesthetized with nitrous oxide, underwent right middle cerebral artery (MCA) occlusion. Eleven cats received an intracarotid infusion of PGI2 in buffered saline pH 10.5 (100 ng/kg/min at 0.01 ml/kg/min), and 11 cats received intracarotid buffered saline pH 10.5 (0.01 ml/kg/min) without therapeutic agents. Treatment with PGI2 was started upon MCA occlusion and continued for 6 hours. Thirty minutes prior to perfusion, the animals were given fluorescein and Evans blue by intravenous injection. The cats were perfused-fixed in vivo with carbon and buffered formalin 6 hours after MCA occlusion. Another 3 cats received tritium labeled intracarotid PGI2, and peripheral venous samples were collected and assayed for PGI2 plasma levels. Mean arterial pressure was stable in PGI2 treated animals during 6 hours of MCA occlusion, while untreated cats had significant progressive hypertension during that period. The rCBF (measured by the intracarotid 133Xe method) decreased markedly in all animals immediately upon MCA occlusion. However, untreated animals had a significant progressive improvement in rCBF during the occlusion period, while PGI2 treated animals had no such improvement. Quantitative EEG changes, gross edema, areas of fluorescein extravasation, patterns of carbon perfusion, and infarct size were not significantly different in the two groups. While most untreated animals had marked Evans blue extravasation after 6 hours of MCA occlusion, most PGI2 treated animals had no such extravasation, indicating some protection of the blood-brain barrier in these animals.

Acute Disease↗
PubMedDate not supplied

[Palisading granuloma of the penis: a variant of subcutaneous granuloma annulare].

INTRODUCTION: Subcutaneous granuloma annulare on the penis has only been reported exceptionally. OBSERVATION: A 41 year-old man presented with four small, asymptomatic nodules on the glans penis. Histological examination of a biopsy revealed a deep palisading granuloma progressing not only around the alcian-blue necrobiosis areas but also around the smooth muscle fibers. The lesion regressed spontaneously after two years of progression. DISCUSSION: Palisading granuloma of the penis appears to be a most particular clinical form of subcutaneous granuloma annulare. It is characterized by small single or multiple nodules localized on the penis. On histological examination, the granuloma is deep and concentrates around the network of smooth muscle fibers of dartoic origin.

Adult↗
PubMedDate not supplied

Naps and depression.

In healthy subjects, napping has often been seen as an "abnormal" form of sleep, while sleep has been considered as a necessary feature of life. Social and cultural biases influence the occurrence of napping behavior. However, several observations indicate the presence in man of a two per day modulation of sleep propensity. On the other hand, alterations of nocturnal sleep have been widely described in affective disorders, but little is known about the presence of daytime sleep in depressed patients and the possible effect of daytime sleep episodes on nocturnal sleep. Some attempts to characterize daytime sleep in depression are reviewed. A recent study based on continuous polygraphic recordings indicate that napping occurrence appears to be similar in depressed patients than in control subjects. However, naps structure and organization were different in depressed patients in comparison to controls. Napping seems thus to be more prevalent in depressed patients than previously assumed. Possible effects of naps on mood, alertness in depressed patients remains to be explored.

Depression↗
PubMedDate not supplied

[Degradation and uptake of 14C labeled casein peptides by mixed bacteria of the rumen].

This work studied the in vitro degradation by mixed rumen bacteria of various 14C-labelled fractions of casein peptides, of known molecular size, added to a total unlabelled casein hydrolysate. Size exclusion HPLC was used in order to segregate the casein peptides according to their molecular weights. Radioactivity associated with the bacteria increased over time. The way 14C was incorporated into the bacteria depended on the size of the labelled peptides initially added. Small peptides (1 to 2 kDa) were very rapidly assimilated, whereas radioactivity coming from larger peptides (5 to 10 kDa) tended to accumulate far more slowly in the bacterial pellet. The disappearance rates of the radioactivity differed between the fractions. The longest peptides disappeared more quickly than the medium-sized ones, which in turn were hydrolysed more rapidly than the smallest ones. Here, the uptake of small peptides seems to be the limiting step of the peptides utilization by bacteria.

Animals↗