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Biomedical subjects

C Rey

Publications and source records attributed to C Rey.

At least 19 recordsLinked to original sources
PubMed1999

Surgical management of progressive pulmonary venous obstruction after repair of total anomalous pulmonary venous connection.

BACKGROUND: The occurrence of a progressive pulmonary venous obstruction after the repair of the total anomalous pulmonary venous connection is a severe complication. OBJECTIVES: The objectives of this study were to retrospectively review the patients with this condition and to report our experience with a new surgical technique with a sutureless in situ pericardium repair. METHODS: Of 178 patients who underwent correction of total anomalous pulmonary venous connection, 16 patients (9%) experienced the development of a progressive pulmonary venous obstruction in a median interval of 4 months (5 weeks-12 years). Three patients had isolated anastomotic stenosis, 4 patients had isolated pulmonary venous ostial stenosis, and 9 patients had both. Pulmonary venous obstruction was bilateral in 7 patients. The surgical procedures used at reoperation included 8 patch enlargements, 5 ostial endarterectomies, 1 intraoperative stenting, and 7 sutureless in situ pericardium repairs. RESULTS: There were 4 deaths after reoperation (4 of 15 patients; 27%). The only significant mortality risk factor was the bilateral location of the pulmonary venous obstruction (P =.045). In patients with isolated anastomotic stenosis or with only 1 pulmonary venous ostial stenosis (n = 5), there was no death, except the patient presenting with a single ventricle. In patients with 2 or more pulmonary venous ostial stenoses (n = 10), there were 3 deaths; 5 of the 7 survivors were successfully treated with the in situ pericardial technique, with normalized pulmonary artery pressure at a mean follow-up of 26 months. CONCLUSION: Progressive pulmonary venous stenosis after repair of total anomalous pulmonary venous connection remains a severe complication when bilateral. The sutureless in situ pericardial repair offers a satisfactory solution, particularly on the right side.

Female↗
PubMed1999

Follow-up results of transvenous occlusion of patent ductus arteriosus with the buttoned device.

OBJECTIVES: The purpose of this presentation is to document results of buttoned device (BD) occlusion of patent ductus arteriosus (PDA) in a large number of patients with particular emphasis on long-term follow-up in an attempt to provide evidence for feasibility, safety and effectiveness of this method of PDA closure. BACKGROUND: Immediate and short-term results of BD occlusion of PDA have been documented in a limited number of children. METHODS: During a six-year period ending August 1996, transcatheter BD closure of PDA was attempted in 284 patients, ages 0.3 to 92 years (median 7) under a protocol approved by the local institutional review boards and FDA with an investigational device exemption in U.S. cases. RESULTS: The PDAs measured 1 to 15 mm (median 4) at the narrowest diameter; 20 were larger than 8 mm and 10 larger than 10 mm. They were occluded with devices measuring from 15 to 35 mm delivered via 7F (N = 140) or 8F (N = 144) sheaths. Successful implantation of the device was accomplished in 278 (98%) of 284 patients. The Qp:Qs decreased from 1.8+/-0.6 (mean+/-SD) to 1.09+/-0.19 (p < 0.001). Effective occlusion defined as no (N = 167 [60%]) or trivial (N = 79 [28%]) residual shunt was achieved in 246 (88%) patients. All types of PDAs, irrespective of the shape (conical, tubular or short), size (small or large) or length (short or long) of the PDA and previously implanted Rashkind devices, could be occluded. Follow-up data, 1 to 60 months (median 24) after device implantation, were available in 234 (84%) patients. Seven (3%) patients required reintervention to treat residual shunt with (N = 2) or without (N = 5) hemolysis. Actuarial reintervention-free rates were 95% at 1 and 5 years. There was gradual reduction of actuarial residual shunts and were 40%, 28%, 21%, 14%, 11%, 10%, 6% and 0% respectively at 1 day, 1, 6, 12, 24, 36, 48 and 60 months after device implantation. Incorporation of folding plug over the button loop in 10 additional patients produced immediate and complete occlusion of PDA. CONCLUSIONS: This large multiinstitutional experience confirms the feasibility, safety and effectiveness of buttoned device closure of PDAs. All types of PDAs irrespective of the shape, length and diameter can be effectively occluded. Incorporation of folding plug over the button loop produces complete PDA occlusion at the time of device implantation.

Adolescent↗
PubMed1999

Direct cytotoxicity of hypoxia-reoxygenation towards sinusoidal endothelial cells in the rat.

AIMS/BACKGROUND: Sinusoidal endothelial cells are the primary target of ischemia-reperfusion injury following liver preservation. The present study was undertaken to examine the susceptibility of sinusoidal endothelial cells to hypoxia-reoxygenation and the potential role of oxygen free radicals in the induction of cell injury. METHODS: Sinusoidal endothelial cells were isolated from rat liver. After 2 3 days of primary culture, the cells were exposed to hypoxia (N2/CO2 95/5) for 120 min and reoxygenation (O2/CO2 95/5) for 90 min. Control cells were exposed to hypoxia alone, to 95% O2 alone or were maintained under normoxic conditions. Human umbilical vein endothelial cells were used as a model of vascular endothelial cells and submitted to the same protocol. Cell viability and lipid peroxidation were assessed by LDH leakage and malondialdehyde production, respectively. In order to test the potential role of xanthine oxidase and mitochondrial dysfunction in cell injury, the cells were treated with allopurinol and potassium cyanide (KCN) respectively. RESULTS: The different gaseous treatments did not affect LDH leakage in human umbilical vein endothelial cells. In sinusoidal endothelial cells, the sequential hypoxia-reoxygenation caused a significant increase in LDH release, malondialdehyde production and xanthine oxidase activity while hypoxia alone had no effect except on xanthine oxidase activity. Allopurinol inhibited xanthine oxidase without preventing cell injury or lipid peroxidation in this latter cell type. CONCLUSIONS: The results suggest that sinusoidal endothelial cells, as opposed to vascular endothelial cells, are susceptible to a direct cytotoxic effect of hypoxia-reoxygenation. This effect occurs in combination with an increase in xanthine oxidase activity and lipid peroxidation, although cell injury is mediated at least in part by mechanisms independent of xanthine oxidase such as mitochondrial dysfunction.

Animals↗
PubMed1998

Results of transvenous buttoned device occlusion of patent ductus arteriosus in adults. International Buttoned Device Trial Group.

Examination of the immediate and follow-up results of transvenous buttoned device occlusion of patent ductus arteriosus suggests that the method is feasible, safe, and effective irrespective of the size and shape of the ductus. Although residual shunts are present, they tend to disappear during follow-up, and complete occlusion at the time of implantation may be achieved by incorporation of a folding plug over the button loop of the device.

Adolescent↗
PubMed1998

Basic fibroblast growth factor adsorption and release properties of calcium phosphate.

Basic fibroblast growth factor (bFGF) is well known as a potent angiogenic factor playing a crucial role in wound-healing processes. Apatitic substrates such as hydroxyapatite and carbonated apatite (CA) could be potential carriers of growth factors because of their physicochemical similarities to bone mineral. These materials have been compared for their bFGF adsorption and release properties. The adsorption of the growth factor was higher on carbonated apatite than on hydroxyapatite, probably owing to environments with labile nonapatitic CO3(2-) and HPO4(2-) groups, along with a higher specific surface area which gives the CA a higher surface reactivity. These environments can be exchanged very rapidly, leading to the release of bFGF. The controlled release of adsorbed growth factor from carbonated apatite could provide means of improving bone healing in the future.

Adsorption↗
PubMed1998

Tumor necrosis factor beta and soluble APO-1/Fas independently predict progression to AIDS in HIV-seropositive patients.

The relationship between serum concentration of different components of the nerve growth factor/tumor necrosis factor (TNF) receptor family, including soluble APO-1/Fas (sAPO-1/Fas) and progression of HIV infection, was analyzed in a case-control study of individuals selected from a cohort of HIV-seropositive patients who were progressing or not progressing to AIDS while being treated with nucleoside analogs. HIV-seronegative healthy controls were also analyzed. The results showed that, despite close matching for immunologic (CD4 cell count, beta2-microglobulin concentration) and virologic (p24 antigen, detection of HIV syncytium-inducing phenotype, plasma HIV viremia) parameters, the baseline serum concentrations of TNF-beta and sAPO-1/Fas were statistically different between progressing and nonprogressing patients. In addition, serum concentrations of TNF-beta and sAPO-1/Fas showed the strongest independent predictive power for progression to AIDS in a multivariate conditional logistic regression model. Because TNF-beta and Fas were suggested to be mediators of antigen-induced cell death (AICD) in HIV infection and sAPO-1/Fas was hypothesized to protect lymphocyte against AICD, these data suggest an important pathogenetic role for AICD in the progression of HIV infection.

Acquired Immunodeficiency Syndrome↗
PubMed1998

Short-term evolution of HIV-1 viraemia and CD4+ cell counts in patients who have a primary mutation to zidovudine.

OBJECTIVE: To investigate the different responses to antiretroviral treatment including zidovudine, of patients harbouring HIV with primary resistance to zidovudine, serum viral load, and CD4+ cell counts, for 24 weeks in a group of antiretroviral-naive patients with the codon 215 mutation of the HIV pol gene and in a control group at the start of treatment. DESIGN: A case-control retrospective study (1989-1996). METHOD: Nineteen out of 210 patients previously studied harboured the codon 215 mutation, had a self-reported compliance with treatment, a minimum follow-up of 24 weeks, and were treated with zidovudine alone or in combination with other nucleoside analogues. These patients were matched with 19 patients with wild-type strains at entry by initial CD4+ cell counts, clinical status, and antiretroviral treatment. RESULTS: During the first 12 weeks, CD4+ cell counts increased (76+/-26 and 64+/-26 x 10(6)/l in wild-type and mutant virus-infected groups, respectively), decreasing slightly until week 24, although no significant differences were found between the two groups studied. Serum viral load decreased in both groups (change in serum viral load of 0.80+/-0.11 log10 and 0.87+/-0.26 log10 copies/ml, wild-type and mutant virus-infected, respectively), although no significant differences were found between groups. CONCLUSION: No significant differences were found between patients with the primary mutation to zidovudine and control patients harbouring wild-type virus in terms of short-term response measured by serum viral load and CD4+ cell counts.

Adult↗
PubMed1998

Resorbable calcium phosphate bone substitute.

The in vitro and in vivo properties of a novel, fully resorbable, apatitic calcium phosphate bone substitute (ABS) are described. The ABS was prepared from calcium phosphate precursors that were hydrated to form an injectable paste that hardens endothermically at 37 degrees C to form a poorly crystalline apatitic calcium phosphate (PCA). The PCA reaction product is stable in vivo as determined by FTIR and XRD analysis of rabbit intramuscular implants of ABS retrieved 4, 7, and 14 days postimplantation. Bone formation and resorption characteristics of the ABS material were characterized in a canine femoral slot defect model. Femoral slot defects in dogs were filled with either autologous bone implants or the ABS material. Sections of femoral bone defect site from animals sacrificed at 3, 4, 12, 26, and 52 weeks demonstrated that new bone formation proceeded similarly in both autograft and ABS filled slots. Defects receiving either material were filled with trabecular bone in the first 3 to 4 weeks after implantation; lamellar or cortical bone formation was well established by week 12. New bone formation in ABS filled defects followed a time course comparable to autologous bone graft filled defects. Histomorphometric evaluation of ABS resorption and new bone formation indicated that the ABS material was greater than 99% resorbed within 26 weeks; residual ABS occupied 0.36+/-0.36% (SEM, n = 4) of the original defect area at 26 weeks. Quantitatively and qualitatively, the autograft and ABS were associated with similar new bone growth and defect filling characteristics.

Animals↗
PubMed1998

Cellular localization of endothelin-1 and increased production in liver injury in the rat: potential for autocrine and paracrine effects on stellate cells.

Endothelin (ET) peptides have been implicated in the pathogenesis of several biological processes within the liver. ET levels are elevated in the circulation of patients with cirrhosis, and recent data suggest that ET may be overproduced in the liver itself in this condition. The aims of the current study were to elucidate the cellular source and expression of endothelin-1 (ET-1) in normal and injured liver, and to investigate its biological effects on stellate cells, the primary target of ETs in the liver. In normal hepatic cells, preproET-1 messenger RNA (mRNA) was detected in only nonparenchymal cells, predominantly in sinusoidal endothelial cells. After biliary fibrosis and early cirrhosis induced by bile duct ligation, preproET-1 mRNA and immunoreactive ET levels increased with progressive injury in whole liver extracts, as well as in isolated stellate and endothelial cell fractions. Eight days after bile duct ligation, the relative increase in preproET-1 mRNA was 1.6- and 7.6-fold above normal in sinusoidal endothelial and stellate cells, respectively. Additionally, immunoreactive ET peptide levels increased by 60% +/- 27% over basal values in sinusoidal endothelial cells and 98% +/- 40% in stellate cells. Cultured stellate cells responded dramatically to exogenous ET-1 by the spreading and up-regulation of smooth muscle alpha actin expression. Furthermore, in early culture before cellular activation, ET-1 (10 nmol/L) caused over a twofold increase in [3H]thymidine incorporation, while activated cells (i.e., those cultured for >1 week) exposed to ET-1 exhibited up to a fivefold decrease in [3H]thymidine incorporation. The data indicate that not only is ET-1 overproduced by both sinusoidal endothelial and stellate cells during liver injury, but that it also has potent effects on features of stellate cell activation. We conclude that autocrine and paracrine production of ET-1 is prominent and is likely to be important in the pathogenesis of hepatic diseases.

Actins↗
PubMed1998

MicroRaman spectral study of the PO4 and CO3 vibrational modes in synthetic and biological apatites.

The carbonate and phosphate vibrational modes of different synthetic and biological carbonated apatites were investigated by Raman microspectroscopy, and compared with those of hydroxyapatite. The nu1 phosphate band at 960 cm-1 shifts slightly due to carbonate substitution in both A and B sites. The spectrum of type A carbonated apatite exhibits two nu1 PO43- bands at 947 and 957 cm-1. No significant change was observed in the nu2 and nu4 phosphate mode regions in any carbonated samples. The nu3 PO43- region seems to be more affected by carbonation: two main bands were observed, as in the hydroxyapatite spectrum, but at lower wave numbers. The phosphate spectra of all biominerals apatite were consistent with type AB carbonated apatite. In the enamel spectrum, bands were observed at 3513 and at 3573 cm-1 presumably due to two different hydroxyl environments. Two different bands due to the carbonate nu1 mode were identified depending on the carbonate substitution site A or B, at 1107 and 1070 cm-1, respectively. Our results, compared with the infrared data already reported, suggest that even low levels of carbonate substitution induce modifications of the hydroxyapatite spectrum. Increasing substitution ratios, however, do not bring about any further alteration. The spectra of dentine and bone showed a strong similarity at a micrometric level. This study demonstrates the existence of acidic phosphate, observable by Raman microspectrometry, in mature biominerals. The HPO42- and CO32- contents increase from enamel to dentine and bone, however, these two phenomena do not seem to be correlated.

Apatites↗
PubMed1998

Differential myogenicity of satellite cells isolated from extensor digitorum longus (EDL) and soleus rat muscles revealed in vitro.

Following muscle damage, fast- and slow-contracting fibers regenerate, owing to the activation of their satellite cells. In rats, crush-induced regeneration of extensor digitorum longus (EDL, a fast muscle) and soleus (a slow muscle) present different characteristics, suggesting that intrinsic differences exist among their satellite cells. An in vitro comparative study of the proliferation and differentiation capacities of satellite cells isolated from these muscles is presented there. We observed several differences between soleus and EDL satellite cell cultures plated at high density on gelatin-coated dishes. Soleus satellite cells proliferated more actively and fused into myotubes less efficiently than EDL cells. The rate of muscular creatine kinase enzyme appeared slightly lower in soleus than in EDL cultures at day 11 after plating, when many myotubes were formed, although the levels of muscular creatine kinase mRNA were similar in both cultures. In addition, soleus cultures expressed higher levels of MyoD and myogenin mRNA and of MyoD protein than EDL satellite cell cultures at day 12. A clonal analysis was also carried out on both cell populations in order to determine if distinct lineage features could be detected among satellite cells derived from EDL and soleus muscles. When plated on gelatin at clonal density, cells from both muscles yielded clones within 2 weeks, which stemmed from 3-15 mitotic cycles and were classified into three classes according to their sizes. Myotubes resulting from spontaneous fusion of cells from the progeny of one single cell were seen regardless of the clone size in the standard culture medium we used. The proportion of clones showing myotubes in each class depended on the muscle origin of the cells and was greater in EDL- than in soleus-cell cultures. In addition, soleus cells were shown to improve their differentiation capacity upon changes in the culture condition. Indeed, the proportions of clones showing myotubes, or of cells fusing into myotubes in clones, were increased by treatments with a myotube-conditioned medium, with phorbol ester, and by growth on extra-cellular matrix components (Matrigel). These results, showing differences among satellite cells from fast and slow muscles, might be of importance to muscle repair after trauma and in pathological situations.

Animals↗
PubMed1998

Long-term cardiovascular consequences of undiagnosed intralobar pulmonary sequestration.

We report the case of a patient with a congenital aortic valve stenosis associated with a long-term undiagnosed intralobar pulmonary sequestration. The important blood flow through the aberrant artery led to progressive congestive heart failure and severe hemoptysis at the age of 25 years. We demonstrate the regression of cardiac symptoms and left ventricular diameter after surgical resection of the sequestration.

Adult↗
PubMed1998

[Medical examination of sexually abused children and adolescents].

Medical examination of sexually-abused children or adolescents aims: 1) to identify clinical evidence of genital or extragenital lesions, 2) to diagnose sexually-transmitted infections or pregnancy, 3) to evaluate the needs for medical care, psychological support, and social investigation. The amount of laboratory evidence depends on the history. Laboratory investigations usually include tests for sperm, bacteriological cultures from all sites, testing for HIV, HCV and HBV antibodies, and the detection of pregnancy. Careful writing of a descriptive medical certificate is an important part of the medical intervention.

Adult↗
PubMed1998

Dynamics of serum cytokines in patients with visceral leishmaniasis and HIV-1 co-infection.

Serum cytokine levels and peripheral T cell subpopulations of HIV-1-infected patients before, during and after active visceral leishmaniasis (VL) were analysed and compared with appropriate controls. At VL diagnosis, co-infected patients showed higher serum levels of interferon-gamma (IFN-gamma) than matched HIV-1 controls without VL, and lower serum concentrations of IL-10 than non-immunocompromised VL controls. High levels of tumour necrosis factor-alpha (TNF-alpha) and IFN-gamma were present in the sera of HIV-1-infected patients with active VL. TNF-alpha remained elevated after VL recovery. A steady decline in the CD4+ cell count, an increase of serum HIV viraemia and a progressive seroconversion for the HIV-1 p24 antigen was observed during the course of VL disease. Thus, an aberrant activation of the TNF system with possible negative immunological and virological consequences is present in HIV-1-infected patients with VL. A more extensive prospective validation of these findings in a bigger cohort of patients will nevertheless be necessary. The results support the hypothesis that different opportunistic infection agents may trigger the production of proinflammatory cytokines during immunodeficiency, and in this way accelerate the course of HIV-1 disease.

AIDS-Related Opportunistic Infections↗
PubMed1998

L-5-hydroxytryptophan does not stimulate LH secretion directly from the pituitary in patients with gonadotrophin releasing hormone deficiency.

OBJECTIVE: There is abundant histological and physiological evidence that serotonin plays a role in the regulation of LH secretion in rats. Studies in human subjects have been few, but their results include the finding that pulsatile administration of L-5-hydroxytryptophan (5-HTP, the immediate precursor of serotonin) amplifies LH secretion in women in the medium-late follicular phase, and that this effect is not due to 5-HTP directly inducing LH secretion by the pituitary. We have investigated whether 5-HTP amplifies LH secretion by enhancing the response of the pituitary to GnRH. PATIENTS: Seven patients aged 20-40 years with hypogonadotrophic hypogonadism (HH) of hypothalamic origin (3 men with Kallmann's syndrome, 2 women without anosmia and with GH deficiency, and 2 women with anorexia nervosa). DESIGN: To prime the pituitary, subcutaneous pulsatile GnRH was administered for 7 days at the rate of one 5-20 micrograms pulse every 90 min. The day before the investigation, this regimen was replaced by 1.5-3 micrograms intravenous pulses at the same frequency. On the day of the investigation, 3 ml blood samples were taken every 10 min from 0850 to 19:00 hours. After the first two samples, the intravenous GnRH pulse frequency was increased to one per hour and was maintained at this level throughout the rest of the study. The first 4 h of the study acted as a control phase allowing determination of the pituitary response to GnRH. At 1300 h, 75 mg of the aromatic-L-amino-acid decarboxylase inhibitor carbidopa was administered orally; carbidopa does not cross the blood-brain barrier, and prevents peripheral conversion of 5-HTP to serotonin. At 1600 h, another 75 mg dose of carbidopa was administered, and administration of 8-20 mg pulses of 5-HTP at a rate of one pulse per hour was begun. MEASUREMENTS: LH was determined in triplicate by an immunoradiometric assay (IRMA), and LH pulses identified by means of a program developed in our laboratory. RESULTS: When pulsatile administration of GnRH was accompanied by administration of carbidopa and 5-HTP, LH pulse amplitude (2.32 +/- 0.71 IU/I) did not differ significantly from its value in either the GnRH+ carbidopa phase (2.58 +/- 1.12 IU/I) or the unaccompanied GnRH phase (2.77 +/- 1.76 IU/I). CONCLUSIONS: L-5-hydroxytryptophan-induced amplification of LH secretion in humans is not due to enhancement of the pituitary response to GnRH. The effect of L-5-hydroxytryptophan must therefore be due to its action on the hypothalamus, where it may be hypothesized that it increases GnRH release.

5-Hydroxytryptophan↗
PubMed1998

Evidence for a role of T-helper type 2 cytokines in the acquisition of human immunodeficiency virus syncytium-inducing phenotype.

BACKGROUND: The objective of the present study was to investigate the relationship between the serum cytokine pattern of T-helper (Th) response and the acquisition of syncytium-inducing (SI) human immunodeficiency virus type 1 (HIV-1) variants in HIV-1-seropositive patients treated with antiretroviral drugs. METHODS: Serum cytokines of Th1/Th2 responses were analysed in a case-control study of 20 individuals selected from a cohort of HIV-1-infected patients without SI variants at entry, who developed or did not develop SI virus during a prospective follow-up. A group of 10 patients with SI variants at study entry was also evaluated. Serum concentration of interferon (IFN) gamma, interleukin (IL) 2, IL-4 and IL-10 was evaluated by mean of a commercial enzyme immunoassay. RESULTS: Despite close matching for immunological (CD4+ cell count) and virological (p24 antigen, serum HIV viraemia) parameters, SI-converting patients showed at baseline significantly lower serum levels of IL-2 and higher concentrations of IL-4 than those who remained persistently negative for SI variants. Shortly after the phenotype conversion, SI-converting patients were characterized by significantly high serum concentration of IL-4 and by low levels of IFN-gamma (Th2-like pattern). Patients with SI phenotype at study entry featured lower mean levels of both IL-4 and IL-10, but mean IFN-gamma and IL-2 values were higher, although the clinical and immunological baseline was also poorer and no statistical analysis could be applied. CONCLUSION: Serum cytokine pattern of Th1/Th2 response differs between patients with NSI and SI phenotype. Our data strongly suggest that the Th2 cytokine pattern could be associated with the acquisition of the SI HIV-1 phenotype.

Case-Control Studies↗