PubMed Health⌕ Search

Biomedical subjects

C Perier

Publications and source records attributed to C Perier.

At least 19 recordsLinked to original sources
PubMed2004

Energy and nutrient intake of elderly hospitalized patients in a steady metabolic status versus catabolic status.

Protein undernutrition enhances frailty and aggravates intercurrent diseases generally observed in elderly patients. Undernutrition results from insufficient food intake and catabolic status. Daily nutrient intakes were explored for hospitalized geriatric patients. Nutrient intake (carbohydrates, lipids, proteins, and calcium) was determined in randomly selected geriatric patients (n=49) over five consecutive days by weighting food in the plate before and after meals. For each geriatric patient, catabolic status and risk factors of undernutrition were considered. Results were compared between patients in a steady status or catabolic status. In steady status patients, protein, lipid and carbohydrate intake but not calcium intake, met recommended dietary allowances (total caloric intake:1535 +/- 370 Cal/day ; protein:1+/- 0.4 g/kg/day ; carbohydrates:55 +/- 7.7 % ; lipids: 30 +/- 6.3 % ; calcium:918 +/- 341 mg/day) . Patients in catabolic status (cardiopulmonary deficiency , neurologic disease , inflammatory process) had lower total caloric intake, lower protein intake and dramatically lower calcium intake (total caloric intake : 1375 +/- 500 Cal/day ; protein :0.9 +/- 0.4 g/kg/day ; carbohydrates : 54 +/- 8.3 % ; lipids : 31 +/-6.2 % ; calcium : 866 +/- 379 mg/day). Nutrient intake was lower in elderly patients hospitalized in short stay care units, perhaps due to failure to recognize suitable nutrient requirements. Protein-caloric undernutrition should be diagnosed early during hospitalization in order to allow appropriate dietary supplementation. However the incidence of protein undernutrition among elderly patients as a cause or a consequence of adverse pathophysiological processes remains a cause of debate.

Aged↗
PubMed2003

Changes in glycation of fibrous type I collagen during long-term in vitro incubation with glucose.

The course of glycation of calf skin fibrous type I collagen was monitored in vitro under physiological conditions during an 8-week incubation period in order to take into account the long half-life of this protein. The formation of glycated compounds was measured by determining fructosamine, pentosidine, and carboxymethyllysine content. The incubation conditions were as physiological as possible in sterile saline phosphate buffer, except glucose concentration. With incubation medium containing 200 mmol glucose, fibrous collagen underwent solubilization; in addition an increase in fructosamine, pentosidine, and carboxymethyllysine content in both solubilized and remaining insoluble collagen was noticed. There was a spontaneous, restricted, and time-dependent native glycated state of collagen; high concentration glucose enhanced the formation of glycated compounds and induced changes in solubility and glycoxidated products. The production of pentosidine during incubation without glucose should be considered as an event resulting from the initial fructosamine. Whereas the production of carboxymethyllysine during long-term incubation with glucose provided indirect proof of an additional oxidative process after early glycated product formation. These experimental observations provide insight into the in vivo context of advanced glycation end product formation in chronic hyperglycemia and aging.

Animals↗
PubMed2003

In vitro glycoxidation of insoluble fibrous type I collagen: solubilization and advanced glycation end products.

The deleterious effects of glycoxidation are dependent on the half-life of proteins. Collagen, the main component of extracellular matrices, is a long live protein and thus may be sensitive to the glycoxidation process. We incubated calf skin fibrous type I collagen in PBS at 37 degrees C with glucose. The fibrous type I collagen was solubilized and an increase in the amount of advanced glycation end products of the solubilized fraction was observed. As there was no bacterial contamination and no proteolytic activities in the incubation medium, the solubilization of fibrous type I collagen is probably due to the speculative production of the free radicals in our experimental conditions. To test this hypothesis, fibrous type I collagen was incubated in PBS with AAPH (2,2'azo-bis 2-aminodinopropane) a free radicals generator. AAPH induced a dramatic and dose dependent solubilization of fibrous type I collagen.

Amidines↗
PubMed2003

Native protein glycoxidation and aging.

Structural and functional alterations of proteins are observed during aging. Glycation of long half-life proteins, involving reducing carbohydrates, leads to the formation of intra and intermolecular cross-links and the production of free radicals. These processes depend on the amount of glucose available and on molecular oxygen which contributes to the production of free radicals. These processes are observed without dysfunction of carbohydrate metabolism and progress with age. However, whether this process is a primary cause or a consequence of aging remains a question of debate. Prevention of excessive glycoxidation could be a goal of recommendations designed to control the tissular alterations occurring in aging.

Aging↗
PubMed2002

Serum pentosidine as an indicator of Alzheimer's disease.

Pentosidine, an advanced glycation end product (AGE), was assayed by HPLC in serum proteins from patients with Alzheimer type dementia (AD), patients with diabetes mellitus (D), and healthy (C) age-matched old subjects (mean age from each group = 84 years). Serum pentosidine was significantly different between the three groups despite similar renal function (serum creatinine < 160 micromol/L). In all groups of patients, pentosidine was independent of glycated hemoglobin (HbA1C) and the early glycation marker fructosamine and appeared to be an independent marker, mainly bound to serum albumin. Pentosidine could be an important factor useful for the diagnosis of Alzheimer's disease.

Aged↗
PubMed2001

Synergy between ascorbate and alpha-tocopherol on fibroblasts in culture.

Ascorbate and tocopherol are important antioxidants that protect cells against oxidative stress. The interaction of ascorbate and alpha-tocopherol in cells is difficult to detect as both ascorbate and alpha-tocopherol are unstable in vitro in a biological medium. We examined the interactions between human dermal fibroblasts, ascorbate and alpha-tocopherol to determine the effects of the vitamins on growth and cell viability. The interaction of ascorbate and alpha-tocopherol was studied in a fibroblast culture medium during 48h. Ascorbate and alpha-tocopherol were detected by fluorimetry after high-performance liquid chromatography (HPLC). Cell growth and cell viability were studied by cell numeration after trypan blue staining. The ascorbate concentration fell in presence of alpha-tocopherol in cell culture medium under all experimental conditions, with or without cells. Ascorbate partly protected alpha-tocopherol but only in presence of cells. Cell viability was preserved by alpha-tocopherol whereas ascorbate enhanced fibroblast growth. The synergy between ascorbate and alpha-tocopherol corresponds to a consumption of ascorbate which spares alpha-tocopherol but only in presence of cells.

Ascorbic Acid↗
PubMed1999

A comparison of 15N proline and 13C leucine for monitoring protein biosynthesis in the skin.

The tracers L 15N-proline and L(1-13C)-leucine were used to explore the synthesis of skin proteins in vivo in rabbits. They orally received a single dose containing an equimolecular mixture of L(1-13C)-leucine and L 15N-proline. The changes in the amounts of these tracers in blood and skin were monitored for a total of 8 h. The data showed the appearance of the two tracers in blood within 15 min and their clearance in 8 h. They were both rapidly (15 min) incorporated into skin proteins, but more proline was incorporated than leucine. We therefore consider L 15N-proline to be a better tracer than L(1-13C)-leucine for studying protein metabolism in the skin.

Animals↗
PubMed1999

Urine glycyl-L-proline increase and skin trophicity.

Glycyl-L-proline (gly-pro) is an end product of collagen metabolism that is further cleaved by prolidase (EC 3.4.13.9); the resulting proline molecules are recycled into collagen or other proteins. We postulated a relationship between defective gly-pro hydrolysis, increased collagen degradation and skin destruction. This relationship was tested using HPLC to measure the gly-pro in urine. 24 hour urine samples were collected from 27 old people (86 +/- 6 years old), of whom 15 were suffering from skin pressure sores of the sacrum or calcaneus. The urine from patients with pressure sores contained significantly more gly-pro than the urine from the control. A cut-off at 7 mumol/mmol creatinine gave the test a positive predictive value of 70%. Collagen breakdown was also increased as indicated by the increase of hydroxyproline (hyp) in the urine. But this breakdown seemed to stop at the gly-pro step.

Aged↗
PubMed1998

Residual inflammatory process after aortoiliac reconstructive surgery.

BACKGROUND: The aim of the present study was to investigate the inflammatory reaction and its evolution in patients who underwent a prosthetic vascular procedure. Moreover the participation of this chronic process, during the follow-up, as a promoting or a consequence of vascular injury must be discussed. METHODS: Thirty-four patients were enrolled in the study. All patients had an aortic disease and underwent a prosthetic vascular procedure. Preoperative exclusion criteria were an emergency situation, diabetes, infection, chronic inflammatory disease, cancer and hemopathy. Postoperative exclusion criteria were the same together with abdominal complications and additional surgery during the follow-up. The inflammatory process was investigated with the measurement of blood acute phase proteins, haptoglobin, alpha1-glycoprotein acid, C-reactive protein and interleukin-6, before, immediately after surgery and several months after surgery. RESULTS: An increase in acute phase proteins was not observed to the same extent for all the studied patients. Before the surgical procedure, chronic inflammatory process was revealed by an increase in haptoglobin (52.9 p 100) and alpha1 glycoprotein acid (52.9 p 100) whereas increase in C-reactive protein (26.4 p 100) and interleukin-6 (92 p 100) are related to an acute process. Later after surgery, the chronic inflammatory process remained but differed from the observed process before surgery only by haptoglobin (61.7 p 100) and interleukin-6 (47 p 100). CONCLUSIONS: The presented results, observed during the follow-up of vascular surgery focused on persistent inflammatory process and the surgical procedure did not modify the time course of this process. The evolutionary disease could be considered as chronic and independent of the local effect.

Aged↗
PubMed1997

Enzyme adaptations of human skeletal muscle during bicycle short-sprint training and detraining.

The effect of sprint training and detraining on supramaximal performances was studied in relation to muscle enzyme adaptations in eight students trained four times a week for 9 weeks on a cycle ergometer. The subjects were tested for peak oxygen uptake (VO2peak), maximal aerobic power (MAP) and maximal short-term power output (Wmax) before and after training and after 7 weeks of detraining. During these periods, biopsies were taken from vastus lateralis muscle for the determination of creatine kinase (CK), adenylate kinase (AK), glycogen phosphorylase (PHOS), hexokinase (HK), phosphofructokinase (PFK), lactate dehydrogenase (LDH) and its isozymes, 3-hydroxy-acyl-CoA dehydrogenase (HAD) and citrate synthase (CS) activities. Training induced large improvements in Wmax (28%) with slight increases (3%) in VO2peak (P < 0.10). This was associated with a greater glycolytic potential as shown by higher activities for PHOS (9%), PFK (17%) and LDH (31%) after training, without changes in CK and oxidative markers (CS and HAD). Detraining induced significant decreases in VO2peak (4%), MAP (5%) and oxidative markers (10-16%), while Wmax and the anaerobic potential were maintained at a high level. This suggests a high level in supramaximal power output as a result of a muscle glycogenolytic and glycolytic adaptation. A long interruption in training has negligible effects on short-sprint ability and muscle anaerobic potential. On the other hand, a persistent training stimulus is required to maintain high aerobic capacity and muscle oxidative potential. This may contribute to a rapid return to competitive fitness for sprinters and power athletes.

Adaptation, Physiological↗
PubMed1989

Study of basement membrane formation in dermal-epidermal recombinants in vitro.

Two different dermal-epidermal recombinants were prepared in vitro and used to study the synthesis and formation of basement membrane. The first was obtained by culturing keratinocytes on the surface of a collagen lattice populated by fibroblasts. The second was prepared by coculture of both keratinocytes and fibroblasts in a collagen lattice. After 6 weeks of culture, the basal lamina was observed with electron microscopy only if keratinocytes were cultivated on top of the collagen lattice populated by fibroblasts. In the second model, however, type IV collagen, laminin, and pemphigoid bullosa antigen could be detected by immunofluorescence as well as synthesis of type IV collagen in the culture, but no basement membrane was observed by electron microscopy. These data demonstrate that, in vitro, basement membrane formation depends not only on the presence of the macromolecular components but also on the culture conditions.

Basement Membrane↗
PubMed1988

[Association between immunity to collagen and the pathology of extracellular matrices].

In a first part, the data of immunogenicity of collagen type II and type IV in physiopathology of extracellular matrices as cartilage and basement membrane, are reviewed. However, in the second part, this conclusion will be examined by basing on the knowledge of the nature of specific sites of these collagens and the variable or non specific humoral immune response towards these collagens in human diseases.

Animals↗
PubMed1988

Multiple clustered dermatofibromas. Evolution over 20 years.

A 37 year-old man developed, over 20 years, multiple clustered dermatofibromas on the left thigh. Three similar cases have been described previously and the benign course of this lesion has been referred to. Analysis of collagen amino acids revealed a sharp increase of hydroxylysine on the fibrous central zone, suggesting an abnormal accumulation of type IV collagen.

Adult↗
PubMed1988

Accumulation of glycolic acid and glyoxylic acid in serum in cases of transient hyperglycinemia after transurethral surgery.

Experimental data are presented here proving the accumulation of glycine in serum after transurethral prostatectomy and increased production of glycine metabolites: serine, alanine, glyoxylic acid, and glycolic acid. The presence of the metabolites glyoxylic acid and glycolic acid was demonstrated by gas-liquid chromatography and mass spectrometry. Glycine, glyoxylic acid, and glycolic acid possess neurological activity, so we examined the pathophysiology of the transurethral prostatectomy syndrome in view of the transient accumulation of these compounds in serum.

Aged↗