Search PubMed⌕ Search

Biomedical subjects

P Dupuy

Publications and source records attributed to P Dupuy.

At least 37 records · Page 2Linked to original sources
PubMed1999

Efficacy of topical 0.05% retinaldehyde in skin aging by ultrasound and rheological techniques.

BACKGROUND: The natural precursor of retinoic acid, i.e. retinaldehyde, has been proven to exert retinoid activities. AIM AND METHODS: The aim of this prospective instrument study was to determine the effect of topical retinaldehyde 0.05% on the physical properties of aging skin. This was performed using two devices, namely a high-resolution (70-80 microm) ultrasound scanner, which visualizes the thickness of both the epidermis and the dermis, and an echorheometer, which assesses the stiffness and elasticity of the skin by suction. In a 1-year study, 21 patients applied retinaldehyde cream 0.05% on the face, while another group of 19 volunteers were only treated with an emollient (control group). Epidermal and dermal thicknesses were measured on the forehead and temple, and stiffness and elasticity were measured on the forehead only. All the instrumental parameters were assessed at baseline and at the end of treatment. RESULTS: Compared to the control group, retinaldehyde treatment induced a significant increase in epidermal thickness of the temple, as well as in cutaneous elasticity (p < 0. 01). Similarly, retinaldehyde treatment tended to increase dermal thickness and reduce cutaneous stiffness, but no statistical difference could be observed between the two groups. CONCLUSION: Taken together, the results further suggest that retinaldehyde has counteracting effects on skin aging

Administration, Topical↗
PubMed1999

Retinaldehyde alleviates rosacea.

BACKGROUND: Anecdotal observations suggest that retinoic acid may be effective in mild rosacea. AIM: Our aim was to investigate, by an exploratory clinical and instrumental study, the effects of a topical formulation with the retinoic acid precursor retinaldehyde, in patients with vascular signs of facial rosacea. METHODS: Female patients were treated with a 0.05% retinaldehyde cream that was applied once daily for 6 months. Clinical assessments of persistent erythema and telangiectasia were performed every month, using a 4-point severity score (absent to severe). The clinical response for each parameter was defined as a decrease of at least 1 grade in the severity score. In addition, erythema was further evaluated by measurement of the a* parameter, using a spectrophotometer on lesional and nonlesional areas. RESULTS: A total of 23 women comprised the study population. At baseline, 10 patients had diffuse erythema, 3 patients had isolated telangiectasia and 10 patients had both. During retinaldehyde treatment, a clinical response was revealed in about 75% of the patients with erythema, after 5 months (p < 0.05). Similarly, isolated telangiectasia responded to retinaldehyde, although to a lesser extent and after a longer period of treatment (46% responders after 6 months, nonsignificant). Using the spectrophotometer, the a* parameter diminished in patients with erythema by about 15%, after 2 months of treatment (p = 0.001). CONCLUSION: This study indicates that retinaldehyde has beneficial effects on the vascular component of rosacea.

Administration, Topical↗
PubMed1999

Tolerance profile of retinol, retinaldehyde and retinoic acid under maximized and long-term clinical conditions.

BACKGROUND: Topical retinoic acid (RA) causes irritation of the skin. To prevent this side effect, natural precursors of RA have been proposed. The aim of the present study was to compare the local tolerance profiles of retinol (ROL), retinaldehyde (RAL) and RA. METHODS: ROL, RAL and RA were studied using repeated insult patch tests for 14 days (n = 6). Similarly, RAL and RA were assessed in long-term clinical use for 44 weeks (n = 355). Clinical scoring on irritation, measurement of transepidermal water loss (barrier function) and laser Doppler blood flow perfusion units (irritation) were performed. RESULTS: Under maximized conditions, an equally low irritation potential for ROL and RAL and a more pronounced irritant effect with RA could be demonstrated clinically (p < 0.05 in the intergroup analysis). Furthermore, RAL and RA induced more scaling than ROL (p < 0.05), and ROL and RA tended to induce more burning/pruritus than RAL (nonsignificant). The TEWL values were low with ROL and high with RAL and RA (nonsignificant, intergroup analysis). The laser Doppler measurements confirmed pro-irritating effects of RA and the nonirritating effects of ROL and RAL (p = 0. 001, intergroup analysis). The long-term clinical study showed that the study population developed a high frequency of erythema (44% of the population), scaling (35%) and burning/pruritus (29%) with RA in the first 4 weeks of treatment, whereas these 3 parameters were significantly less frequent with RAL (p < 0.0001 in the intergroup analysis). CONCLUSION: The natural retinoids ROL and RAL do have a good tolerance profile, in contrast with the irritating potential of RA.

Administration, Cutaneous↗
PubMed1998

Biochemical, cellular and pharmacological activities of a human neuropeptide FF-related peptide.

We report on the biochemical, cellular and pharmacological activities of SQA-neuropeptide FF (Ser-Gln-Ala-Phe-Leu-Phe-Gln-Pro-Gln-Arg-Phe-NH2), a peptide sequence contained in the human neuropeptide FF (neuropeptide FF, Phe-Leu-Phe-Gln-Pro-Gln-Arg-Phe-NH2) precursor. Quantitative autoradiography revealed that, in the superficial layers of the rat spinal cord, SQA-neuropeptide FF displayed the same high affinity for [125I]1DMe ([125I]D-Tyr-Leu-(NMe)Phe-Gln-Pro-Gln-Arg-Phe-NH2) binding sites (Ki = 0.33 nM) as did neuropeptide FF (Ki = 0.38 nM). In acutely dissociated mouse dorsal root ganglion neurones, SQA-neuropeptide FF reduced by 40% the depolarisation-induced rise in intracellular Ca2+ as measured with the Ca2+ indicator, Fluo-3. In mice, 1DMe and SQA-neuropeptide FF dose-dependently inhibited the antinociceptive effect of intracerebroventricular (i.c.v.) injections of morphine, but SQA-neuropeptide FF was less potent than 1DMe. Furthermore, SQA-neuropeptide FF, as well as 1DMe, produced marked hypothermia following third ventricle injections in mice. These data demonstrate that the human peptide, SQA-neuropeptide FF, exhibits biochemical and pharmacological properties similar to those of neuropeptide FF or neuropeptide FF analogues, and belongs to the neuropeptide FF family.

Analgesics, Opioid↗
PubMed1998

Profilometric evaluation of photodamage after topical retinaldehyde and retinoic acid treatment.

OBJECTIVE: We compared the activity and tolerance profile of a 0.05% retinaldehyde cream with a 0.05% retinoic acid cream and the retinaldehyde vehicle in patients with photodamaged skin of the face. METHODS: A silicone replica of the left crow's feet area was taken at baseline and at weeks 18 and 44. Skin replicas were then analyzed by means of an optical profilometry technique. Standard wrinkle and roughness features were then calculated and statistically analyzed. The tolerance profile of the test products was also clinically evaluated during the entire study. RESULTS: A total of 125 patients (40 in the retinoic acid group, 40 in the retinaldehyde group, and 45 in the vehicle group) were studied. At week 18, a significant reduction of the wrinkle and roughness features was observed with both retinaldehyde and retinoic acid. At week 44, a less pronounced reduction was demonstrated in both active groups. No statistically significant changes were observed with the retinaldehyde vehicle at any assessment point. A total of 135 patients constituted the safety population. Retinaldehyde was well tolerated during the entire study. In contrast, retinoic acid caused more local irritation, and affected compliance of the patients. CONCLUSION: Retinaldehyde was efficacious and well tolerated in patients with photodamage.

Adult↗
PubMed1997

Topical application of a platelet-activating factor (PAF) antagonist in atopic dermatitis.

Platelet-activating factor (PAF acether) is a lipid mediator with a potent proinflammatory activity. Results derived both from in vitro and in vivo studies suggest a possible role of this substance in the pathophysiology of atopic dermatitis. A double-blind, randomized, multi-center, within-patient study was performed to evaluate the efficacy of a topically applied PAF antagonist (RO-24-0238) in 36 patients with atopic dermatitis. Over a period of 28 days, 0.25 ml of the PAF antagonist and the vehicle (placebo) were applied twice daily on opposite sites of symmetrical lesions (measuring 10 to 20 cm2 each). The overall assessment of the therapeutic efficacy did not demonstrate a superior effect of the PAF antagonist in comparison to placebo, and this was the same with the individual study parameters erythema, scaling, induration and exudation. For reducing pruritus, as assessed by the patient using a visual analogue scale, a statistically significant action was documented during the first 2 weeks of the study (p < 0.04; Wilcoxon rank sum test), with a continued, yet not statistically significant efficacy after weeks 3 and 4. The exact role of the pathological events of atopic dermatitis that might be influenced by a PAF antagonist remains to be determined, but the anti-pruritic component of this substance especially deserves further scientific interest.

Administration, Topical↗
PubMed1996

Calcium carbonate crystals promote calcium oxalate crystallization by heterogeneous or epitaxial nucleation: possible involvement in the control of urinary lithogenesis.

A large proportion of urinary stones have calcium oxalate (CaOx) as the major mineral phase. In these stones, CaOx is generally associated with minor amounts of other calcium salts. Several reports showing the presence of calcium carbonate (CaCO3) and calcium phosphate in renal stones suggested that crystals of those salts might be present in the early steps of stone formation. Such crystals might therefore promote CaOx crystallization from supersaturated urine by providing an appropriate substrate for heterogeneous nucleation. That possibility was investigated by seeding a metastable solution of 45Ca oxalate with vaterite or calcite crystallites. Accretion of CaOx was monitored by 45Ca incorporation. We showed that (1) seeds of vaterite (the hexagonal polymorph of CaCO3) and calcite (the rhomboedric form) could initiate calcium oxalate crystal growth; (2) in the presence of lithostathine, an inhibitor of CaCO3 crystal growth, such accretion was not observed. In addition, scanning electron microscopy demonstrated that growth occurred by epitaxy onto calcite seeds whereas no special orientation was observed onto vaterite. It was concluded that calcium carbonate crystals promote crystallization of calcium oxalate and that inhibitors controlling calcium carbonate crystal formation in Henle's loop might play an important role in the prevention of calcium oxalate stone formation.

Calcium Carbonate↗
PubMed1996

[Increase of alpha-fetoprotein in pancreatic endocrine tumors with hepatic metastases. Apropos of 2 cases].

We report two cases of metastatic non-functioning pancreatic endocrine tumour with very elevated plasma levels of alpha-fetoprotein. In these two cases, serial plasma levels of alpha-fetoprotein, initially normal, correlated well with hepatic tumour progression and were associated with fatal outcome. These results suggest that elevated plasma concentration of alpha-fetoprotein may be caused by metastatic pancreatic endocrine tumour and than alpha-fetoprotein serial measurement may be useful in prognostic evaluation.

Antineoplastic Agents↗
PubMed1995

Analysis of the soluble organic matrix of five morphologically different kidney stones. Evidence for a specific role of albumin in the constitution of the stone protein matrix.

Our aims were to analyze the protein composition of the organic matrix of urinary stones and to investigate the role of albumin in its constitution. Five different morphological types of stones were studied. Proteins extracted from the stone were submitted to sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and analyzed by immunoblotting with antibodies to 13 urinary proteins. Nine of the 13 proteins were found in all types of stone: human serum albumin (HSA), alpha 1-acid glycoprotein (alpha 1-GP), alpha 1-microglobulin (alpha 1-M), immunoglobulins (Igs), apolipoprotein A1 (apo-A1), transferrin (Tr), alpha 1-antitrypsin (alpha 1-T), retinol-binding protein (RBP) and renal lithostathine (RL). The beta 2-microglobulin (beta 2-M) was present only in calcium oxalate and uric acid stones. In contrast, ceruloplasmin, haptoglobin and Tamm-Horsfall protein (THP) were detected in none of them. Because HSA appeared as the major protein component in all stones, we wondered whether it might play a specific role in the constitution of the stone matrix. Association of HSA with urinary proteins that were present in stones was demonstrated by showing that proteins present in the matrix comigrated with HSA on gel filtration, whereas proteins that were absent did not. Moreover, HSA induced the binding of stone matrix proteins to an albumin-specific affinity column. Finally, we evidenced HSA binding to calcium oxalate monohydrate (COM) crystals in a solution similar to urine.(ABSTRACT TRUNCATED AT 250 WORDS)

Albumins↗
PubMed1995

Inhibitor of the release of mast cell mediators does not improve the psoriatic plaque.

The number of mast cells is increased in psoriatic lesions and this is particularly prominent in their early phase. Mediators released by mast cells may interfere with various aspects of cutaneous inflammation and epidermal proliferation. Therefore, the aim of the present investigation was to find out whether a 4-week treatment period with Tiacrilast, a highly potent inhibitor of mast cell degranulation, might have antipsoriatic potential. A total of 31 patients with plaque-type psoriasis were evaluated after treatment with a 3% Tiacrilast hydrogel and hydrogel alone, in a double-blind, placebo-controlled, within-patient comparative study. No statistically significant improvement of the Tiacrilast-treated plaques compared to the hydrogel-treated sites could be demonstrated. Therefore, the present study does not provide evidence of a potential role of mast cell degranulation in the treatment of psoriasis.

Adult↗
PubMed1994

Pancreatic lesions and modifications of pancreatic juice in tropical chronic pancreatitis (tropical calcific diabetes).

Seventeen Indian patients from Kerala State and 13 Indian controls were submitted to a dietary inquiry. Indian patients and controls had a low fat intake (40.8 g +/- 12.1 and 34.5 g +/- 11.0 per day, respectively) and a moderately low protein intake (52.8 +/- 9.5 and 47.8 +/- 11.3 g per day); 11 patients and 6 controls did not consume cassava. Pure nonactivated pancreatic juice was collected at endoscopy in 10 Indian patients who presented with tropical calcific diabetes, 12 apparently normal controls from the same area, and 23 apparently normal French controls. The only significant differences between Indian and French controls was a decreased pancreatic protein response to cerulein and an increased calcium concentration in the Indian subjects. The pancreatic juice of Indian patients was characterized by decreased volume, normal bicarbonate concentration, increased protein concentration when the acinar cells were not stimulated, with no response to cerulein, increased calcium concentration, and normal citrate concentration. These changes are very similar to the changes observed in French patients with chronic alcoholic pancreatitis. The lesions of 14 surgical resection pancreatic specimens from South Indian patients presenting with tropical pancreatitis were compared to pancreata from French patients presenting with chronic alcoholic pancreatitis. The only difference was that intraductal plugs, lesions of the duct epithelium, and retention cysts or pseudocysts were less frequent in Indians. These results show that the two nutritional forms of pancreatic lithiasis, alcoholic and tropical, have similar histological lesions and biochemical modifications of pancreatic juice.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Clinical evaluation of topical isotretinoin in the treatment of actinic keratoses.

BACKGROUND: Retinoids have been shown to improve the manifestations of skin photodamage, including actinic keratoses. OBJECTIVE: The efficacy and tolerability of isotretinoin 0.1% cream in the treatment of actinic keratoses were evaluated in a randomized, double-blind, placebo-controlled, parallel-group study. METHODS: One hundred patients were randomly assigned to treatment with 0.1% cream or vehicle twice daily for 24 weeks to the face, the scalp, and the upper extremities. Patients were assessed every 4 weeks by the investigators, who counted and recorded the number of lesions in each treatment area. The 93 patients who had at least one postbaseline assessment were included for efficacy analysis. Local tolerability was evaluated at each study visit. RESULTS: On the face, the reduction in number of actinic keratoses (mean +/- SEM) at the end of treatment was greater for patients treated with isotretinoin (3.9 +/- 0.6, i.e., 66% of patients with a reduction > 30%) than with placebo (1.7 +/- 0.5, i.e., 45% of patients with a reduction > 30%); this difference was statistically significant (p = 0.001). No significant drug effect was seen for lesions on the scalp or upper extremities. Mild to moderate local reactions with isotretinoin abated with reduced treatment frequency. CONCLUSION: Our results suggest that isotretinoin 0.1% cream cannot compete with more rapid treatments of actinic keratoses. However, its effect on facial lesions may be beneficial during long-term treatment of associated sun-damaged skin.

Administration, Topical↗