Search PubMed⌕ Search

Biomedical subjects

B Faivre

Publications and source records attributed to B Faivre.

At least 19 recordsLinked to original sources

Does beak coloration of male blackbirds play a role in intra and/or intersexual selection?

In many bird species, males may show brightly coloured traits and variance in male mating success may be explained by female preference and/or competition between males favouring the most coloured males. Male beak coloration has been suggested to play an important role in the pairing pattern of European blackbirds. Here, we investigate female preference and male-male interactions in relation to male beak coloration in this species. We used a field experiment to measure female and male responses toward stuffed decoys showing either of two beak coloration representing the extremes of the natural variation from yellow to orange. Decoys were situated on the centre of plots and behaviours of males and females approaching the decoy were recorded. The total number of males and females approaching the decoy did not differ between the two model treatments. Similarly, there was no difference in the mean time that males and females spent near the decoy. The number of males displaying aggressive postures did not differ between treatments and no female adopted a sexual posture. We discuss the relevance of our results and potential limitations associated with the experimental procedure.

Journal Article↗

[Hospitalization criteria for erysipelas: prospective study in 145 cases].

INTRODUCTION: Two recent studies conducted in France among general practitioners have shown that they only hospitalized between 20 to 50 percent of patients with erysipelas seen in private practice. We therefore conducted a hospital-based, prospective study designed to determine the hospitalization criteria for erysipelas, since a number of patients are also hospitalized directly through the emergency department. PATIENTS AND METHODS: This prospective, hospital-based study, included patients hospitalized for clinical diagnosis of erysipelas in 9 centres in north-eastern France. Clinical data were recorded using a standard questionnaire filled-in during the first 72 hours of hospitalization. They included: demographic (name and first name initials, age, sex) and clinical (location of erysipelas) characteristics, as well as the origin of the patient (home, emergency department, other department), the reasons for hospitalization (severity of local or systemic signs, suspicion of deep vein thrombosis, location on the face, age over 60 years, associated diseases, absence of improvement after ambulatory treatment, socioeconomic reasons or on principle hospitalization). Patients hospitalized by (or without) a general practitioner were compared using Chi-2 and Student t tests. RESULTS: One hundred forty-five adults (80 women and 65 men; mean age 61 +/- 20 years) were included in the study: 89 patients (61 p. 100) were hospitalized by a general practitioner whereas 56 (39 percent) went directly to the emergency department. In 128/145 cases (88 p. 100), erysipelas was localized on the lower limbs. The mean number of reasons for hospitalization per patient was of 2.2 +/- 1.2. The most frequent reason for hospitalization was an associated disease (diabetes, obesity, alcoholism, immunodeficiency), present in 77 cases (53 p. 100). Patients hospitalized through a general practitioner were older than those hospitalized directly through the emergency department (68 vs 51 years; p<0.001). Patients hospitalized by a general practitioner more frequently had an erysipelas located on the lower limbs (94 p. 100 vs 79 p. 100; p<0.001) and the mean number of reasons for hospitalization was greater (2.4 vs 1.7; p<0.001), especially suspicion of deep vein thrombosis and elevated mean age. The treatment started during hospitalization was intravenous penicillin G in 67 cases (46 p. 100), oral pristinamycin in 28 cases (19 p. 100) and intravenous or oral amoxicillin in 9 cases (6 p. 100). COMMENTS: This study demonstrates the existence of two distinct courses of hospitalization for erysipelas. Patients hospitalized by a general practitioner were older and their erysipelas more frequently located on the lower limbs and deep vein thrombosis was suspected. Our study also shows the emergence of a population of patients younger and without medical supervision, for whom the general practitioner is replaced by the emergency department of the local hospital. Nevertheless, the most frequent reason for hospitalization in both groups is the existence of an associated disease, possibly responsible for further complications.

Adult↗

The neuropeptide calcitonin gene-related peptide differently modulates proliferation and differentiation of smooth muscle cells in culture depending on the cell type.

Calcitonin gene-related peptide (CGRP) is a neuropeptide present around vasculature very early during development, when smooth muscle cells (SMC) are still proliferating and not yet totally differentiated. We investigated the effects of CGRP on proliferation and differentiation of SMC in culture; 10(-7) M CGRP added in the medium of cultured smooth muscle cells every 2 days did not significantly changed cells growth rate in 1% FCS. At the opposite, this treatment modulated proliferation of cells grown in 10% FCS medium. Two distinct populations of SMC with different growth rates were obtained from our primary cultures. SMC which proliferated slowly in the presence of 10% fetal calf serum (FCS) had growth rates positively influenced by CGRP. The quantity of alpha-smooth actin expressed by these cells was not influenced by the peptide. On the contrary, SMC which proliferated more rapidly in 10% FCS medium had growth rate inhibited by CGRP. In these cells, CGRP significantly reduced the amount of expressed alpha-smooth actin, an index of SMC differentiation. In both cases, the peptide significantly increased the level of mRNA for all the actin genes. In the light of this dual role of CGRP, it can be presumed that this peptide controls smooth muscle cells proliferation and differentiation in vivo and could thus regulate the homeostasis of the vessel wall.

Actins↗

Modification of the rat aortic wall during ageing; possible relation with decrease of peptidergic innervation.

Structural changes of the male rat aorta were followed from birth to old age in male and female rats. In males, the vessel media width and area progressively increase concomitantly with a decrease of nuclei density during ageing, suggesting an hypertrophy of the smooth muscle cells. These correlations were however not evidenced in females. TUNEL-positive cells were found in media of 4 and 6 months in both sexes, mainly on the luminal side and in the adventitia. When biochemical markers were investigated with immunohistochemistry, media was uniformly stained by the anti-vimentin and anti-alpha-smooth actin at all stages investigated. On the contrary, the surface of media stained with anti-desmin decreased during ageing, especially on the luminal side. As observed with electron microscopy, with ageing the endothelium is replaced by small cells with pseudopodia adhering to the vestigial elastic lamina and infiltrating into the extracellular matrix left after the disappearance of smooth muscle cells. In addition, in the older rats (25-29 months) the elastic laminae are completely disorganised. Hypertrophy of the smooth muscle cells was confirmed by this approach. In parallel to this study, perivascular peptidergic innervation was stained with antibodies against calcitonin gene-related peptide (CGRP), substance P (SP), neuropeptide Y (NPY), and vasoactive intestinal polypeptide (VIP) at different ages during the whole life of rats. These peptides are present in stages younger than 6 months, then gradually disappear. In one year animals and older, the peptidergic innervation has totally disappeared. We discuss the possible role of peptidergic innervation in the control of the vessel wall cellular stability during ageing.

Actins↗

Pair-bonding in birds and the active role of females: a critical review of the empirical evidence.

Over the recent years the role of females in maintaining or breaking the pair-bond in socially monogamous birds has received growing attention. Here, we review the overall evidence for a direct and predominant role of female behaviour in initiating or preventing divorce and its relevance for the understanding of both interspecific and intraspecific variation in divorce rate in monogamous bird species. The evidence is so far limited to a few species. We discuss the relevance of some alternative explanations and confounding factors. We conclude that the possible predominance of females in both initiating divorce or limiting its occurrence deserves further consideration. Future studies should favour experimental approaches, such as mate-removal experiments.

Journal Article↗

EMLA cream as a topical anesthetic for the repeated mechanical debridement of venous leg ulcers: a double-blind, placebo-controlled study.

BACKGROUND: A granulating surface is important for skin grafting and healing of leg ulcers. Mechanical debridement to remove necrotic tissue often must be stopped before completion because of pain. OBJECTIVE: Our purpose was to assess the effect of EMLA cream on the number of debridements required to obtain a clean ulcer and on pain during debridement and to determine its safety after repeated doses. METHODS: In this randomized double-blind, placebo-controlled study, 69 patients with venous leg ulcers received cream before debridement until a clean ulcer was obtained (or a maximum of 15 debridements). RESULTS: EMLA decreased the median number of debridements required for a clean ulcer (EMLA 11.5, placebo >15; P = .019) and decreased pain by 50% (P = .003). Plasma levels of lidocaine, prilocaine, and their main metabolites were low without any apparent accumulation. CONCLUSION: EMLA produces effective pain relief for the debridement of leg ulcers and shortens the time to a clean ulcer.

Administration, Cutaneous↗

Rheological behaviour of red blood cells suspended in hemoglobin solutions. In vitro study comparing dextran-benzene-tetra-carboxylate hemoglobin, stroma free hemoglobin and plasma expanders.

Circulating volume expansion for intentional hemodilution and/or resuscitation of hemorrhagic shock can be performed with hemoglobin-based oxygen carriers (HBOC) which, in addition to oxygen transport, have vasoactive effects through poorly documented mechanisms. Among these, the effects of HBOC on red blood cell (RBC) rheology are relatively unknown. The aim of the present in vitro study was to measure the rheological effects of human hemoglobin bound to benzene-tetracarboxylate substituted dextran (Dex-BTC-Hb) as an example of chemically modified hemoglobin. The viscosity was assessed with a capillary and a rotational viscometer for shear rates of 0.5-128 s-1. Erythrocyte aggregation was determined by analysis of the red light backscattered in a RBC suspension and with a rheoscope. The deformability was determined by the pressure-flow relationship of the RBC suspensions passed through polycarbonate filters. At hematocrit of 0.35 l/l and at low shear rates, the viscosity of RBC was higher in the presence of Dex-BTC-Hb as compared to free Hb, Dex-BTC, Dextran 40 (Plasmacair), modified fluid gelatin (MFG-Plasmion) or hydroxyethyl starch (HEA-Elohes). The effect on erythrocyte aggregation of Dex-BTC-Hb was greater than that of standard solutions, but close to that of MFG or HEA. There was no apparent change in RBC deformability. Dex-BTC-Hb, unlike free Hb, has a hyperaggregating effect on RBC, similar to that of some clinically used volume expanders. This hyperaggregating effect could influence the in vivo rheological behavior of substituted Hb by increasing shear stress.

Blood Substitutes↗

Hemoglobin autooxidation/oxidation mechanisms and methemoglobin prevention or reduction processes in the bloodstream. Literature review and outline of autooxidation reaction.

The amount of circulating methemoglobin in healthy humans is the result of a balance between methemoglobin production (from autooxidation and oxidation) and hemoglobin reduction. Hemoglobin autooxidation and oxidation are very complex and are not well understood. This article analyses the literature on hemoglobin autooxidation, oxidation and reduction and sets out a sequence of reactions for the oxidation of hemoglobin and the ways in which the percentage of methemoglobin is regulated or methemoglobin production prevented. Most of the information concerns erythrocyte hemoglobin, but plasma extracellular hemoglobin (from hemolysis or hemoglobin-based blood substitutes) is also considered where possible.

Hemoglobin A↗

[Serum and salivary immunoglobins A in atopic dermatitis. Prospective and comparative case control study].

UNLABELLED: IgA system has been poorly studied in patients with atopic dermatitis (AD). Previous studies have showed that a transient serum IgA deficiency in infancy could lead to atopic disease. In addition, decrease in salivary IgA has been demonstrated in patients with AD. The purpose of our work was to study the IgA system both in serum saliva in patient with AD. PATIENTS AND METHOD: We conducted a controlled prospective study from January 1994 to May 1996. 46 patients with AD and 52 healthy volunteers matched for sex and age were included. Atopic patients fulfilled at least three major and three minor features defined by Hanifin and Rajka. None above atopic criteria were present in the control group. Saliva was collected using a small cylinder of a cotton-wool-like substance (Salivette) kept in the buccal fold. Serum and saliva samples were assayed for IgA using standard nephelometric method and time-resolved immunofluorometric assay. Secretory IgA were assayed by a sandwich-type enzyme linked immunosorbent assay. Blood eosinophils and serum IgE were also evaluated. RESULTS: IgA and secretory IgA were detected in all serum and saliva collected. No statistically significant difference were observed in serum or in saliva for both IgA and secretory IgA between patients with AD and controls. As expected, blood eosinophils and serum IgE were significantly increased in patients with AD. DISCUSSION: None patients (atopic or control) exhibited IgA deficiency. Although no statistically significant, a trend to higher concentrations of serum and salivary IgA was observed in patients with AD suggesting a stimulation of mucosa-associated lymphoid tissue in these patients.

Adolescent↗

[Pulsed Doppler ultrasonography to measure the vasoactive effects of hemoglobin-dextran 10-benzene-tetracarboxylate, a potential erythrocyte substitute].

The effects of Dextran-Benzene-Tetracarboxylate-Hemoglobin (Dex-BTC-Hb), a chemically-modified hemoglobin-based oxygen carrier, on the vascular tone were compared to those of standard solutions, i.e. the animal's own blood and a 50 milligrams albumin solution, by measuring the carotid blood flow velocity, the mean arterial pressure, the heart rate and respiratory frequency, in anesthetized Hartley guinea pigs after a hemorragic shock. Stroma-free hemoglobin induced 40% hypertension and a 110% rise in blood flow velocity immediately after injection. The velocity was still increased 38%, 3 hours after injection. The calculations of the vascular resistances showed an increase in carotid vascular tone. Dex-BTC-Hb brought about 35% hypertension for two hours with no significant modifications of the vascular tone. These effects are similar to those of the albumin solution. These results indicate that, unlike stroma-free hemoglobin, Dex-BTC-Hb does not significantly affect the vascular tone, probably because of its slight interaction with the factors that regulate vascular tone.

Animals↗

Eosinophilic pustular folliculitis in infancy: report of two affected brothers.

We describe two brothers with eosinophilic pustular folliculitis. Both had recurrent crops of papules and pustules, primarily affecting the scalp. The eruption began in the neonatal period. Both children had a leucocytosis with eosinophilia. Histology revealed folliculitis, with an infiltrate in which eosinophils were predominant. Bacteriological and fungal cultures of pustules were negative. There was a good clinical response to treatment with a topical corticosteroid and dapsone. We review the 28 previously reported cases of eosinophilic pustular folliculitis in infancy. The occurrence of this disorder in brothers suggests that an inherited or contagious factor may be involved in its aetiology.

Adrenal Cortex Hormones↗

In vitro effect of dextran-benzene-tetra-carboxylate hemoglobin on human blood rheological properties.

While conducting pharmacological investigations into oxygen carriers, it is important to study the in vitro and in vivo rheological behavior of blood cells in the presence of such preparations. With regard to the original nature of human hemoglobin bound to benzene tetracarboxylate substituted dextran (Dex-BTC-Hb), it seemed necessary to study its rheological effect in a simulated in vitro hemorrhagic shock compensated by a blood substitute. The viscosity of substitutes was determined as well as several rheological parameters after 0, 3 and 6 hours incubation periods of red blood cells with substitutes: viscosity of blood-substitute mixtures at different levels of plasma substitution erythrocyte aggregation of blood-substitute mixtures by determining the velocity of rouleau formation and the cohesion of rouleau network. This work yielded several observations: The viscosity of Dex-BTC-Hb was slightly higher than those of solutions of native Hb, Dex-BTC T10, Dextran 40 (Plasmacair, modified fluid gelatin (Plasmion and hydroxyethyl starch 200 (Elohes). The substitution of a blood volume with Dex-BTC-Hb, corresponding to a compensated 45% hemorrhagic shock, slightly increased the viscosity of hemodiluted blood as compared to other substitutes. In the presence of Dex-BTC-Hb, the aggregation of erythrocytes appears to be increased as compared to standard solutions. Yet, the effect was close to that of Plasmion or Elohes.

Blood Flow Velocity↗

Assessment of dextran 10-benzene-tetracarboxylate-hemoglobin, an oxygen carrier, using guinea pig isolated bowel model.

With the aim of assessing of dextran-benzene-tetracarboxylate hemoglobin as an oxygen carrier, we studied histological changes in the intestinal loop in anesthetized guinea pig. The intestinal tissue being very sensitive to hypoxia, an innervated loop was vascularly perfused with open-flow during one hour at zero hematocrit. To estimate the capacity of hemoglobin solution to oxygenate this tissue, we observed the mechanical and histological changes in the organ and the arterio-venous difference in PO2, oxyhemoglobin, deoxyhemoglobin and we compared them with human albumin, Tyrode and non-modified hemoglobin. The PO2 arteriovenous differences were 51.9 +/- 7.1 torr (m +/- SEM) for Tyrode, 40.2 +/- 6.4 torr for albumin solution, 113.7 +/- 6.5 torr for non-modified hemoglobin and 132.7 +/- 6.8 torr for dex-BTC-Hb. Compared to albumin and Tyrode solutions, hemoglobin solutions transferred more oxygen to tissues. The desaturation of dex-BTC-Hb was significantly superior (p < 0.05) to the one non-modified hemoglobin. With Hb solutions, this desaturation increased with time and it depended on the perfusion flow. The structure of jejunal villi when perfused with a hemoglobin solution, remained almost normal and the loop was still active. Nevertheless, non-modified hemoglobin leaked from the vessels to the lumen and caused edema and a rupture of overlapping epithelium at the tip of the villi. With dex-BTC-Hb, such histological modifications were less significant. With albumin and Tyrode, all villi were totally necrosed and the loop was completely inert. We have demonstrated that dextran-benzene-tetracarboxylate hemoglobin had the ability to maintain the tissue alive thanks to its good capacity to release oxygen and its satisfactory vascular persistence. Dex-BTC-Hb solution can answer to needs of tissue.

Animals↗

[Evaluation of hemoglobin dextran 10-benzene-tetracarboxylate, oxygen transporters, using a model of guinea pig intestine].

With the aim of assessing of dextran-benzene-tetracarboxylate hemoglobin as an oxygen carrier, we studied histological changes in the intestinal loop. The intestinal tissue being very sensitive to hypoxia, in the anesthetized guinea pig, an innervated loop was vascularly perfused with open-flow during one hour at zero hematocrit. To estimate the capacity of hemoglobin solution to oxygenate this tissue, we observed the mechanical and histological changes in the organ and the arterio-venous difference in PO2, oxyhemoglobin, deoxyhemoglobin and we compared them with human albumin, Tyrode and non-modified hemoglobin. The PO2 arterio-venous differences were 51.9 +/- 7.1 torr (m +/- SEM) for Tyrode, 40.2 +/- 6.4 torr for albumin solution, 113.7 +/- 6.5 torr for non-modified hemoglobin and 123.1 +/- 7.9 torr for dex-BTC-Hb. Compared to albumin and Tyrode solutions, hemoglobin solutions transferred more oxygen to tissues. The desaturation of dex-BTC-Hb was significantly superior (p < 0.05) to the one non-modified hemoglobin. The structure of jejunal villi when perfused with a hemoglobin solution, remained almost normal and the loop was still active. Nevertheless, non-modified hemoglobin leaked from the vessels to the lumen and caused oedema and a rupture of overlapping epithelium at the tip of the villi. With dex-BTC-Hb, such histological modifications were less significant. With albumin and Tyrode, all villi were totally necrosed and the loop was completely inert. We have demonstrated that dextran-benzene-tetracarboxylate hemoglobin had the ability to maintain the tissue alive thank to its good capacity to release oxygen and its satisfactory vascular persistence.

Animals↗

Effect of a conjugated oestrogen (Premarin) cream on ageing facial skin. A comparative study with a placebo cream.

The effects of Premarin cream on ageing facial skin were studied in a randomised, double-blind, parallel group study. Fifty-four women aged 52-70 years who had moderate to severe facial cutaneous ageing, applied 1 g of either Premarin cream (0.625 mg conjugated oestrogens per gram of cream), or placebo cream (same composition with the exclusion of conjugated oestrogens) to the face nightly for 24 weeks. Each morning these women protected their face with a sunblock SPF 15. Skin thickness was measured by B-scan ultrasonic echography, and skin microrelief by profilometry. Each subject's facial appearance was also evaluated by the subject herself and by the clinician. A statistically significant difference (P = 0.013) in favour of Premarin cream was detected in skin thickness at week 24. Skin thickness (dermal plus epidermal) for the women who used Premarin cream increased from 1.56 +/- 0.20 mm at baseline to 1.68 +/- 0.19 mm, compared with 1.52 +/- 0.20 mm at baseline to 1.59 +/- 0.19 mm in the placebo group. Premarin cream was also significantly more effective than placebo cream in improving fine wrinkles according to the results at weeks 12 and 24 (P = 0.010 and P = 0.012, respectively). Significant improvement from baseline was detected in both groups for roughness, laxity and mottled pigmentation and/or lentigines; however, there was no significant difference in these parameters between the two treatment groups. No subjects discontinued treatment for a safety reason. In conclusion, Premarin cream produced better results than the placebo cream; the difference was statistically significant for skin thickness and fine wrinkles. Premarin cream was well tolerated locally, and its general safety was good.

Administration, Topical↗

Evaluation of cutaneous photodamage using a photographic scale.

Clinical assessments of photodamage are based upon a subjective evaluation of characteristic features such as wrinkling and pigmentary change, and are influenced by inter-observer differences in grading criteria. In an effort to standardize the grading of photodamage severity, we have developed a six-point photographic scale in which each of the six grades of overall photodamage severity is depicted by three photographs. The use of three photographs to portray each grade illustrates the diversity and range of manifestations within each grade. This photographic scale was tested by two groups of dermatologists, who used it on two occasions to grade the overall photodamage severity of a single group of female Caucasian subjects. Results indicate high inter-observer agreement, with chance-corrected agreement ranging from 0.44 to 0.63 and from 0.54 to 0.76 on the first and second occasions, respectively. Intra-observer repeatability was high, with chance-corrected agreement ranging from 0.56 to 0.78. Inter- and intra-observer differences were within one category in nearly all cases. Similar grades were assigned by dermatologists with and without experience in treating photodamaged patients. We conclude that application of this scale results in consistent and reproducible clinical evaluations of overall photodamage severity in Caucasian subjects. The scale may be useful in categorizing subjects for epidemiological studies, or in selecting patients for clinical trials.

Dermatology↗

Hydration, transepidermal water loss, pH and skin surface parameters: correlations and variations between dominant and non-dominant forearms.

The aim of this study was to examine differences between the skin of both forearms with regard to several parameters: hydration (skin capacitance), transepidermal water loss (TEWL), pH and skin surface parameters. Possible correlations between measurements were investigated. Thirty-three healthy women (32.6 +/- 8.4 years) participated in the study. The different parameters were measured on each volar forearm (dominant and non-dominant) at precisely delineated sites. TEWL and developed length (DL) were significantly increased on the dominant forearm (P < 0.001 and P < 0.01, respectively). In addition, a correlation matrix was calculated with the differences between dominant and non-dominant forearms for all the parameters measured. Only the skin surface parameters were found to be interrelated with this statistical approach. These data confirm that randomization between forearms is essential in the design of a reliable experimental plan, and indicate the lack of relationship between these measurements as assessed in a group of healthy young women.

Adult↗

Human hemoglobin conjugated to carboxylate dextran as a potential red blood cell substitute. II--Pharmacotoxicological evaluation.

A solution of human hemoglobin bound to benzene tetracarboxylate substituted dextran, whose physicochemical characteristics are defined in part I, was evaluated in vivo as a potential red blood cell substitute. Further experiments show: - the confirmation of a lack of acute toxicity in mice and guinea pigs after injection of 12.5%, 25% and 50% of the blood mass and the absence of death in rabbits having undergone three successive 25% hemorrhagic shocks in three week intervals. A plasma half-life of 9.5 +/- 0.5 hours in 70-75% hemorrhagic shocks on guinea pigs and the absence of dex-BTC-Hb in thoracic and abdominal cavities. No tissue oedema was noticed. Total hemoglobinuria did not exceed 10% of the injected hemoglobin quantity and only involved free hemoglobin. A lack of death in 70-75% hemorrhagic shocks and survival times ranging from 10 hours to 3 days in total exchange transfusions in guinea pig experiments.

Animals↗