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Biomedical subjects

P Brun

Publications and source records attributed to P Brun.

175 records · Page 10Linked to original sources
PubMedDate not supplied

In vitro reconstructed tissues on hyaluronan-based temporary scaffolding.

Tissue engineering offers the possibility to reconstruct tissue substitutes in order to replace lost or damaged tissues. The availability of appropriate biomaterial devices is essential to allow in vitro cultured cells to behave as in the original tissues in vivo. In our studies we utilized a seminatural biomaterial made up by the benzyl ester of hyaluronan to grow keratinocytes, fibroblasts and chondrocytes. Keratinocytes and fibroblasts were isolated from human foreskin. Cells were separately cultured on two different hyaluronan based biomaterial devices for the first 15 days and then co-cultured for an additional period of 2 weeks. Keratinocytes gave rise to a well-differentiated epithelial layer, while fibroblasts were able to synthesize all the main extracellular molecules inside the biomaterial spaces, forming dermal-like tissues. When these two tissues were co-cultured, a skin equivalent was formed with a dermal-epidermal junction. Chondrocytes were obtained from chick-embryo sterna and cultured for 21 days inside a non-woven scaffolding made up of a hyaluronan-based biomaterial. Cells were able to organize themselves into nodules embedded in a dense metachromatic substance in which type II collagen was present. Data from this study suggest that this novel class of hyaluronan derived biomaterials is suitable for different cell culture and in vitro tissue reconstruction.

Journal Article↗
PubMedDate not supplied

Clostridial collagenase releases bioactive fragments from extracellular matrix molecules.

The current study was designed to investigate the biological role of small extracellular matrix fragments in wound healing. Human burn eschar tissue was digested with bacterial collagenase, and small aminoacidic fragments were inoculated in both human dermal fibroblast cultures and polyvinyl alcohol sponges implanted subcutaneously in the rat. Proliferation assays on cell cultures and biochemical and histologic analyses of the animal model were then performed. Results showed that fibroblasts treated with low concentrations of eschar fragments duplicated significantly faster than controls. Biochemical and histologic data from sponge implants showed that the inflammatory response was augmented by eschar-derived fragments at postoperative day 2, whereas protein and hydroxyproline synthesis were decreased at day 14. In conclusion, these data substantiate that the application of bacterial collagenase to débride necrotic tissue may have an indirect healing effect resulting from the local release of bioactive matrix-derived fragments.

Animals↗
PubMedDate not supplied

M-mode and two-dimensional echocardiography in the routine follow-up of central venous catheters in children receiving total parenteral nutrition.

A retrospective study in 38 children (1 day to 7 years) on total parenteral nutrition (TPN) (1 month-24 months) with a central venous catheter (CVC) evaluated the contribution of two-dimensional echocardiography (2D) and M-mode in the follow-up of CVC location and early diagnosis of related complications. Fifty examinations were performed routinely in 21 patients (group I) and 40 in 17 patients for sepsis of the CVC or clinical suspicion of thrombosis (group II). The tip of the CVC was located in the upper right atrium in 17 cases (45%), superior vena cava in 14 cases (37%), jugular or subclavian vein in 5 cases (13%), and was not visualized in 2 cases (15%). In group I, 2D was normal in 19 cases, and catheter thrombosis suspected in 2 was not confirmed by digital angiography (DA). In group II, 2D was normal in 11 cases. In 6 patients, subxiphoid and suprasternal planes identified superior vena cava thrombus in the right atrium (DA confirmed the diagnosis in 2). In 2 pulmonary embolism occurred (1 case died); the remaining patients were successfully treated by medical therapy and removal of the catheter. Echocardiography is a useful noninvasive technique to control CVC tip location and follow-up. In this study, the sensitivity of cardiac thrombus detection by echocardiography was 100% and the specificity 93%; this method appeared, therefore, appropriate for early detection of cardiac thrombosis in pediatric patients on TPN.

Catheterization, Central Venous↗
PubMedDate not supplied

Tumor necrosis factor-alpha (TNF-alpha) in seasonal allergic conjunctivitis and vernal keratoconjunctivitis.

PURPOSE: To quantify the presence of the proinflammatory cytokine tumor necrosis factor-alpha (TNF-alpha) in allergic conjunctivitis. MATERIALS AND METHODS: Tears and peripheral blood samples were collected from patients with seasonal allergic conjunctivitis (SAC, n=6), vernal keratoconjunctivitis (VKC, n=12), and normal subjects (CT, n=12). From an additional six nonactive allergic patients, tears were collected before and after specific conjunctival allergen challenge (CAC). Upper tarsal conjunctival biopsies were obtained from five CT and five VKC patients. TNF-alpha in tears was measured by enzyme-linked immunoassay and identified in tissues by immunohistochemistry. RESULTS: Tear TNF-alpha levels in VKC patients were significantly increased compared to CT (p=0.03), and were significantly correlated with the severity of the disease. No differences were found between SAC and CT tear samples. TNF-alpha serum levels were higher in VKC than CT, however, this difference was not statistically significant. After CAC, tear TNF-alpha levels were found increased in only one of six patients. In VKC tissues, TNF-alpha positive cells were significantly increased compared to CT (p=0.03). CONCLUSIONS: TNF-alpha may have a significant role in severe forms of allergic conjunctivitis.

Adolescent↗
PubMedDate not supplied

Equally efficacious asthma management with budesonide 800 micrograms administered by Turbuhaler or with beclomethasone dipropionate > or = 1500 micrograms given through a pressurized metered-dose inhaler with spacer. The French Budesonide Trial Group.

To avoid the side effects associated with long-term administration of high doses of inhaled glucocorticosteroids, they should be used at the lowest effective dose. This study compared the clinical efficacy of budesonide given via a dry-powder, inspiratory flow-driven device (Turbuhaler), at a daily dose of 800 micrograms, with beclomethasone dipropionate (BDP) 1500 to 2000 micrograms given via pressurized metered-dose inhaler (pMDI) with spacer to adults requiring the latter dose of BDP to control their asthma. The study was performed as a 2-week run-in, 8-week open, randomized, multicenter, parallel-group design. Adult asthmatics with a forced expiratory volume in 1 second 55% or more of predicted normal and receiving BDP 1500 to 2000 micrograms daily entered the study. After a 2-week run-in, one group continued with BDP and the other was switched to budesonide through the Turbuhaler. After 8 weeks, morning peak expiratory flow (PEF) had increased by 5.9 L/min from a mean of 390 L/min in the budesonide group and by 1.9 L/min from a mean of 402 L/min in the BDP group. No clinically or statistically significant differences between groups were evident with regard to the change in this primary variable. Similarly, only small changes in evening PEF and secondary variables of lung function were seen, with no statistically significant difference between groups. The authors concluded that both treatments were equivalent in managing asthma in adult patients with stable asthma.

Administration, Inhalation↗
PubMedDate not supplied

[Kidney failure induced by administration of acyclovir. Apropos of 2 cases].

BACKGROUND: There have been several reports of acyclovir-induced renal failure, when the drug has been administered intravenously and/or associated with water restriction. CASE REPORT: Case n. 1: A 14 year-old boy, was treated with intravenous acyclovir because of an acute encephalitis, possibly due to Herpes viral infection. The acyclovir dose was given erroneously high, 24 mg/kg, 3 times/day, with water restriction, 30 ml/kg/day. Creatininemia increased from 70 to 200 mumol/liter after 48 hours of treatment and was 426 mumol/liter after 5 days. It decreased within a few days after the acyclovir dose was reduced to 6 mg/kg/day and the water intake was increased to 80 ml/kg/day. Case n. 2: A 17 year-old girl was suffering from chronic renal failure due to bilateral kidney hypoplasia associated with hypertension (creatinine clearance: 40 ml/min/1.73 m2). She was given intravenous acyclovir, 20 mg/kg/day, with water restriction, 30 ml/kg/day, to treat acute meningoencephalitis, possibly due to Herpes infection. Creatininemia increased from 200 to 450 mumol/l within 8 days of treatment; it returned to initial values 5 days after cessation of acyclovir and rehydration. CONCLUSION: These 2 cases confirm the risk of renal impairment when acyclovir is administered intravenously. The risk is greater after bolus injections and when high doses are used. Water restriction is an additional risk, as was the chronic renal insufficiency in our second patient. A scheme of acyclovir therapy based on initial values of creatininemia is mandatory.

Acute Kidney Injury↗
PubMedDate not supplied

[Usefulness of self-assessment scales for anxiety and depression in internal medicine].

The rating scales and questionnaires of quantitative psychopathology constitute an aid for the resident physician in the recognition of depressive and anxiety disorders in medical wards. The specific interest of these scales is more in the symptomatic intensity than in the diagnosis. A structured questionnaire leading to a DSM-III diagnosis of mood disorders shows the differences of these two approaches. Analyses of the results of two new self-assessment scales for depression compared to those of a diagnostic instrument permit to appreciate the respective prevalence of mood disorders and the intensity of depressive symptomatology.

Affective Symptoms↗
PubMedDate not supplied

[Post-infectious Epstein-Barr virus encephalitis].

A case of meningoencephalitis is reported in a 14 year old boy. After an acute onset with fever and coma, the outcome was rapidly favorable. Antibody titers in acute and convalescent sera demonstrated recent infection with EBV. EBV encephalitis appears to be a post-infectious encephalitis with no direct viral invasion of the CNS and no acute viral replication.

Adolescent↗