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Biomedical subjects

B Gasser

Publications and source records attributed to B Gasser.

At least 19 recordsLinked to original sources
PubMed2006

Femoroplasty--augmentation of the proximal femur with a composite bone cement--feasibility, biomechanical properties and osteosynthesis potential.

BACKGROUND: Analogous to vertebroplasty, cement-augmentation of the proximal femur ("femoroplasty") could reinforce osteoporotic bones. This study was to evaluate (i) the feasibility of femoroplasty with a composite cement (Cortoss), (ii) its influence on femoral strength by mechanical testing and (iii) the feasibility of stable osteosynthesis of the augmented fractured bones. METHODS: Nine human cadaveric femora were augmented with a composite bone cement, the surface heat generation monitored, and then tested biomechanically against their native contralateral control to determine fracture strength. Subsequently, thirteen reinforced and fractured femora were osteosynthetized by different implants and tested against their osteosynthetisized, non-augmented contralateral control. FINDINGS: Cement could be injected easily, with a moderate temperature rise. A positive correlation between BMD and fracture load and a significant increase in fracture load (+43%) of the augmented femora compared to their native controls (6324 N and 4430 N, respectively) as well as a significant increase in energy-to-failure (+187%, 86 N m and 30 N m, respectively) was found. Osteosynthesis was possible in cement-augmented femora. Osteosynthetisized femora showed equivalent strength to the intact controls. INTERPRETATION: Augmentation of the proximal femur with composite bone cement could be of use in prophylaxis of fractures in osteoporotic femurs. Osteosynthesis of the fractured augmented bones is a challenging procedure but has a good chance to restore strength.

Biomechanical Phenomena↗
PubMed2004

[Allergic fungal sinusitis: ten cases].

OBJECTIVES: Diagnosis, nosological individualization, and treatment of allergic fungal sinusitis remain difficult and controversial despite the increasing number of publications. We present ten cases of allergic fungal sinusitis and review the literature to highlight the main clinical, radiological, biological, immunoallergological, mycological, and therapeutics features. MATERIAL AND METHODS: This retrospective study included ten patients (six men and four women, mean age 45 years) with allergic fungal sinusitis diagnosed on the basis of all diagnostic criteria reported in the literature. RESULTS: Six patients had isolated allergic fungal sinusitis which was associated with allergic bronchopulmonary aspergillosis in the four others. Treatment combined endoscopic sinus surgery and corticosteroids, which provided good results in six patients and average results in three. Treatment failure was observed in one patient. CONCLUSION: As in the case of allergic bronchopulmonary aspergillosis, a set of clinical, radiological, histopathological, immunoallergological and mycological criteria is necessary for precise diagnosis and to avoid fungal drift. The most appropriate endoscopic sinus surgery and the best corticosteroid regimen remain to be determined.

Adult↗
PubMed2004

Anodic plasma-chemical treatment of CP titanium surfaces for biomedical applications.

The anodic plasma-chemical (APC) process was used to modify CP titanium surfaces for biomedical applications. This technique allows for the combined chemical and morphological modification of titanium surfaces in a single process step. The resulting conversion coatings, typically several micrometer thick, consist mainly of titanium oxide and significant amounts of electrolyte constituents. In this study, a new electrolyte was developed containing both calcium-stabilized by complexation with EDTA-and phosphate ions at pH 14. The presence of the Ca-EDTA complex, negatively charged at high pH, favors incorporation of high amounts of calcium into the APC coatings during the anodic (positive) polarization. The coating properties were evaluated as a function of the process variables by XPS, GD-OES, Raman spectroscopy, SEM and tensile testing, and compared to those of calcium-free APC coatings and uncoated CP titanium surfaces. The maximal Ca/P atomic ratio in the coating produced with the new APC electrolyte was approximately 1.3, with higher Ca concentrations than reported in conventional APC coatings. The dissolution behavior of the incorporated, amorphous CaP phases was investigated by exposure to a diluted EDTA solution. The coatings produced in the new electrolyte system exhibit favorable mechanical stability. The new APC technology is believed to be a versatile and cost-effective coating technique to render titanium implant surfaces bioactive.

Adsorption↗
PubMed2004

Prenatal diagnosis of a true fetal tetraploidy in direct and cultured chorionic villi.

Prenatal diagnosis of a true fetal tetraploidy in direct and cultured chorionic villi: Tetraploidy is characterized by four complete sets of chromosomes (4n= 92). Although it has been frequently reported in spontaneous abortions, tetraploidy is extremely rare in term pregnancy. Most of late surviving patients are diploid/tetraploid mosaics and present severe mental and physical impairment. Up to date, only five tetraploidies were ascertained in the prenatal stage in amniocytes and/or fetal blood lymphocytes. No one has been reported in chorionic villi probably because tetraploidy is generally considered in this tissue as a false positive result due to confined placental mosaicism (CPM) or placental culture artefacts. We report here on a case of tetraploidy detected in chorionic villi because of fetal cystic hygroma. We discuss the reliability of this diagnosis and propose guidelines in the follow-up of tetraploidies detected after chorionic villus sampling (CVS). Thus a misdiagnosis of this poor condition will be avoided at best and an appropriate genetic counseling will be given to the parents.

Amniocentesis↗
PubMed2003

Polysyndactyly, complex heart malformations cardiopathy, and hepatic ductal plate anomalies: an autosomal recessive syndrome diagnosed antenatally.

A distinct syndrome was ascertained in a 3-year-old girl and her brother. The proband was the first child of first cousin parents. She was born after an uneventful pregnancy. At birth, multiple congenital anomalies were noted: ptosis of the left eyelid, hypertelorism, anteverted nares, large fontanel, long philtrum, ungueal hypoplasia, polysyndactyly, single transverse crease, complex cardiopathy, and hepatic cysts. During another pregnancy of the mother, fetal ultrasonographic examination showed an hypertrophy of the right ventricle and atria, a dextroposition of the aorta, a bilateral renal pelvis dilatation, and a club foot. After termination of the pregnancy, necropsy showed facial anomalies, a small penis, a polysyndactyly, a ventricular septum defect, and a malformation of the ductal plate. Bonneau et al. [1983: J Genet Hum 2:93-105] described a family in which three sibs had a complex cardiac malformation, hexadactyly of the first toe, and syndactyly of the third and fourth fingers. Rajab [1997: Clin Dysmorphol 6:85-88] described two sibs with similar features in an Omani family. The sibs described in this report had anomalies of the ductal plate which were not reported in the two other families. These new findings are in favor of autosomal inheritance of this condition which is amenable to antenatal diagnosis.

Child, Preschool↗
PubMed2003

Theoretical and experimental model to describe the injection of a polymethylmethacrylate cement into a porous structure.

A theoretical approach was used to determine the distribution of a poly(methylmethacrylate) cement after its injection into a porous structure. The predictions of the model were then compared to experimental results obtained by injecting a polymethylmethacrylate cement into an open-porous ceramic filter. The goal was to define a model that could predict what factors affect the risk of cement extravasation and hence how the risk of cement extravasation can be minimized. The calculations were based on two important rheological laws: the law of Hagen-Poiseuille and the law of Darcy. The law of Hagen-Poiseuille describes the flow of a fluid in a cylindrical tube. The law of Darcy describes the flow of a fluid through a porous media. The model predicted that the extravasation risk was decreased when the cement viscosity, the bone pore size, the bone permeability and the bone porosity were increased, and when the diameter of the extravasation path and the viscosity of the marrow were decreased. Experimentally, the effect of the marrow viscosity and extravasation path could be evidenced. Therefore, the model was believed to be an adequate approximation of the experimental behavior. In conclusion, the experimental results demonstrated that the model was adequate and that the best practical way to decrease the risk of extravasation is to increase the cement viscosity.

Bone Cements↗
PubMed2003

Allelic imbalance at loci containing FGFR, FGF, c-Met and HGF candidate genes in non-small cell lung cancer sub-types, implication for progression.

Fibroblast growth factors (FGF), hepatocyte growth factor (HGF) and their receptors, FGFR and c-Met, are essential components of the regulatory networks between the epithelium and mesenchyme in embryonic lung, but their respective roles in tumour growth are not clear. We performed allelotyping at loci containing the candidate genes FGFR-1-2-3-4, FGF-1-2-7-10, c-Met and HGF in 36 non-small cell lung cancer (NSCLC) (20 squamous-cell carcinomas (SQC) and 16 adenocarcinomas (ADC)), by surrounding each locus with two microsatellites (MS), as close as possible to the genes of interest. Unexpectedly, SQC and ADC were frequently altered at all of these loci, and SQC showed more simultaneously altered loci. In ADC, alterations at the 15q13-22 locus (FGF7 candidate gene) were significantly more frequent. Thus, these loci showed different patterns of molecular alterations between SQC and ADC. Finally, alterations at loci containing FGFR and HGF candidate genes were inversely correlated to the lymph node status in SQC and ADC, respectively.

Adult↗
PubMed2003

Recurrent neural tube defects associated with partial trisomy 2p22-pter: report of two siblings and review of the literature.

We report on two male siblings with partial trisomy 2p22-pter and partial monosomy 15q26-qter resulting from a maternally derived translocation t(2;15)(p22;q26). Both fetuses had different neural tube defects (craniorachischisis in the first fetus and anencephaly in the second fetus) which were detected by sonographic examination at the end of the first trimester of pregnancy. This report demonstrates the importance of chromosomal analysis in the etiologic exploration of neural tube defects and supports the importance of 2p24 triplication in neural tube development.

Anencephaly↗
PubMed2002

Sarcoma of the thyroid gland: a case report.

Sarcoma of the thyroid gland is a very uncommon malignant tumor (<1% of thyroid cancers) characterized by severe local course and rapid metastatic dissemination and very poor prognosis. We report the case of an 84-year-old woman hospitalized for expiratory dyspnea, severe malnutrition and swallowing disorders leading to bronchial infection. She had a voluminous (20 cm) extra-thoracic right-neck goiter with a considerable superficial venous pattern that had developed on an old goiter before growing recently. CEA and calcitonin levels were normal. The cervical-thoracic CT demonstrated a partially necrosed heterogeneously hypodense tumor compressing the esophagus and the trachea with displacement of adjacent structures which were not directly invaded. Large areas of necrosis and a probable metastatic image measuring 3 cm in the right median pulmonary lobe were observed. Macrobiopsy disclosed grade 3 sarcoma. Complete resection delivered a 3.170 kg tumor. Histology confirmed the diagnosis of sarcoma without neoplastic extension. Apart from right recurrent palsy, the initial post-operative period was satisfactory and the patient was discharged. Four and a half months later she was rehospitalized with local recurrence with a large metastatis in the right lung. She died two weeks later.

Aged↗
PubMed2001

Recovery after relief of fetal urinary obstruction: morphological, functional and molecular aspects.

The effects of obstruction [urinary tract obstruction (UTO)] and relief on renal development were examined in an experimental model in the fetal lamb. Bladder outlet obstruction was performed at 60 days of gestation; relief was performed by vesicoamniotic shunting at 90 days of gestation. Studies were carried out in obstructed (OF60; n = 11), shunted (SF; n = 5), and control fetuses (CF; n = 11) at 120 days of gestation. Fetal UTO produced either hydronephrosis (64%) or dysplasia (36%); dysplasia was always associated with a reduction in the number of glomeruli [950 +/- 99 (dysplasia) vs. 1,852 +/- 249 (CF) glomeruli/section]. Obstructed fetuses had lower creatinine clearance [0.76 +/- 0.41 (OF60) vs. 0.96 +/- 0.21 (CF) ml x min(-1) x kg(-1)], higher sodium fractional excretion [17.2 +/- 20.3 (OF60) vs. 2.4 +/- 3.7% (CF)], and higher urinary concentration [80 +/- 30 (OF60) vs. 43 +/- 22 (CF) micromol/l] than controls. In SF, the number of glomeruli was increased at 120 days of gestation (1,643 +/- 106 glomeruli/section) compared with nondiverted fetuses (1,379 +/- 502 glomeruli/section), and the temporal pattern of PAX2, disrupted after obstruction, was restored. In conclusion, early fetal UTO leads to either renal hydronephrosis with normal glomerular development or dysplasia with a decreased number of glomeruli; in utero urine diversion performed before the end of nephrogenesis may allow a reversal of the glomerulogenesis arrest observed.

Animals↗
PubMed2001

[Congenital fetal neuroblastoma].

Neuroblastoma are pediatric tumors of neural crest origin, most often localized in adrenal glands and infrequently congenital. We report two fetal cases found at autopsy, performed at 24 and 28 weeks of gestation, respectively. The 24 week old fetus did not show any malformation; systematic histological analysis found neuroblastoma cells in both the adrenal glands and the retroperitoneal fat tissue. The 28 week old fetus was hydropic and exhibited a nodule (3 cm) in the posterior mediastinum, next to the thoracic spinal cord. This tumor responded to a neuroblastoma associated with small metastatic foci in the adrenal glands, the liver and the frontal brain cortex. The placenta was abnormally heavy and showed hemorrhagic and necrotic areas. Microscopically plugged clumps of neuroblastoma cells were found inside fetal vessels. Immunohistochemistry was employed in both cases and the cells showed immunoreactivity for NSE, NB 84, chromogranin, synaptophysin and neurofilaments, while desmin, MIC 2, and protein S-100 were negative. Congenital neuroblastomas are rare and, to our knowledge this is the thirteenth report of congenital neuroblastoma associated with placental metastasis.

Adrenal Gland Neoplasms↗
PubMed2000

About composite materials and their use in bone surgery.

Composite materials consist of two or even more different material components or phases, which are combined with the aim to improve physical, mechanical and/or biological properties. Such structures are designed to fulfil very specific requirements with respect to a selected device application making full use of their higher weight-specific strength and/or stiffness. Furthermore, these materials offer an opportunity for constructing radiolucent devices. In medical technology, composite materials mainly consist of a polymer matrix and fibres as a reinforcement phase. Composites similar to those known from technical applications reveal a number of specific biological problems. This is due to the materials and manufacturing processes available for the construction of such composites preventing their unrestricted use in direct bone contact. Nevertheless, an application potential for these materials in bone surgery exists and justifies further research and development efforts.

Composite Resins↗
PubMed2000

Evaluating mechanical adhesion of sol-gel titanium dioxide coatings containing calcium phosphate for metal implant application.

The adhesion of thin (< 10 microm) sol-gel calcium phosphate-titanium dioxide films bonded to a titanium substrate was studied using two different tests: a rotating-bending test and a tensile bond test. The former evaluates the impact of both the coating procedure and the surface pre-treatment on the resistance to fatigue of the substrate as well as the adhesion of the coating; the latter measures the tensile adhesion strength of the coating. Both tests gave similar results. A reduction of the thickness of the coating or an increase of the roughness of the substrate improves the quality of the interface. A comparison of the adhesion of the calcium phosphate-titanium dioxide film with that of a pure calcium phosphate coating obtained by a similar route suggests the involvement of a chemical component in the binding.

Calcium Phosphates↗
PubMed2000

Prognostic implications of a positive bronchial resection margin.

OBJECTIVE: This retrospective study evaluates probability of survival and mode of recurrence in patients with a microscopically positive bronchial resection margin following resection for primary bronchogenic carcinoma, as well as influence of radiotherapy on survival. METHODS: From January 1986 to July 1997, 40 patients had a microscopically positive bronchial resection margin following a macroscopically complete resection (17 lobectomies, three bilobectomies, four sleeve-lobectomies, and 16 pneumonectomies). Tissue diagnosis was squamous cell carcinoma in 32 patients, adenocarcinoma in four, adenosquamous carcinoma in two and neuroendocrine carcinoma in two. Lymph node status was N0 in 14 patients, N1 in 10, and N2 in 16. The bronchial margin contained carcinoma in situ in 20 patients, invasive mucosal carcinoma in five, and peribronchial infiltration in 15. All patients except the three most recent underwent adjuvant radiation therapy. RESULTS: At the conclusion of the study (January 31st, 1999), 30 patients had died: two with post-operative complications, 17 with progressive disease, ten without relation to cancer, and one under undefined circumstances. Six of 10 unrelated deaths were interpreted as respiratory complications of radiotherapy. Recurrent disease appeared in 24 patients (60%). Nineteen had progression of initial disease (47.5%): metastatic spread in 12 (30%), isolated local recurrence in four (10%), and combined local recurrence and metastases in three (7.5%). Five patients developed metachronous cancer, with bronchial location in four (10%) and laryngeal in one (2.5%). 5-year survival (Kaplan-Meier) in 20 patients with carcinoma in situ was 38.7+/-13.7% (median 31 months), but rose to 55.0+/-16. 6% when excluding seven deaths not related to cancer (five of whom were secondary to radiotherapy) (chi(2)=3.080; P=0.0792). Survival in 13 patients classified N0 was 51.3+/-16.3% (median 61 months), and 71.1+/-18.0% following exclusion of unrelated deaths (chi(2)=3. 939; P=0.0472). Adverse prognosis of peribronchial infiltration was correlated to a positive N status (13 N2 and 2 N1), 5-year survival being 20.0+/-10.3% (median: 18 months). CONCLUSIONS: Prognosis of peribronchial infiltration is similar to N2 disease. In situ carcinoma does not influence survival per se. Local control of disease is probably in part due to radiotherapy. However, the high prevalence of unrelated late deaths suggests an adverse impact of radiotherapy on survival.

Adenocarcinoma↗
PubMed2000

Pulmonary migratory infiltrates and pachypleuritis in a patient with Crohn's disease.

Crohn's disease can be associated with several respiratory manifestations. We report here a case of pulmonary migratory infiltrates associated with bilateral pleural thickening and peripheral eosinophilia. The histopathological findings show an association of necrotizing nodules, eosinophilic infiltration in the non-abscessed lung tissue, areas of non-caseating epithelioid granulomas, and an extensive pleural fibrosis. The different histopathological findings are detailed and the responsibility of either Crohn's disease or treatment by mesalazine is discussed.

Adult↗
PubMed1999

Local control of disease and survival following bronchoplastic lobectomy for non-small cell lung cancer.

BACKGROUND: This study was designed to determine whether bronchoplastic resection could be an alternative to pneumonectomy in patients with operable primary lung cancer. METHODS: From 1980 to 1996, 63 patients (59 males and four females; mean age 62 +/- 7 years) underwent a bronchoplastic lobectomy for non-small cell lung cancer, indicated because of a disabled respiratory function in 34 patients, and performed electively in 29 patients. There were 38 right upper lobectomies, four bilobectomies, one middle lobectomy combined with lower lobe apical segmentectomy, ten left upper and ten left lower lobectomies. The bronchoplasty was a full sleeve in 24 patients, and a bronchial wedge resection in 39. RESULTS: A single patient died post-operatively (1.6%). Specific procedure-related complications are summarized as follows: six anastomotic complications managed conservatively (9.5%), 15 space problems (23.8%), nine sputum retentions (14.2%). Pathologic staging classified 30 patients in stage I, 21 patients in stage II, and 12 in stage IIIA. Estimated 5-year survival was 69.7 +/- 9.8% in stage I, 37.1 +/- 12.1% in stage II, and 8.3 +/- 8.0% in stage IIIA. Fourteen patients (22.2%) developed locoregional recurrence. Three of them died with local recurrence alone, whereas 10 developed metastatic progression; a single patient is alive following completion pneumonectomy. According to stage, three recurrences occurred in stage I (10%), six in stage II (28%), and five in stage IIIA (38%). Actuarial freedom from local recurrence was significantly higher after elective procedures (P = 0.019); there was a trend towards improved outcome following right-sided procedures (P = 0.079) and following wedge bronchoplasty (P = 0.055). Five patients experienced a second primary cancer (7.9%), which was resected in four. CONCLUSION: Bronchoplastic resections achieve local control and long-term survival comparable to standard resections in patients with stage I or II disease, and may be considered as a valuable alternative to pneumonectomy.

Adult↗
PubMed1999

Thin films of calcium phosphate and titanium dioxide by a sol-gel route: a new method for coating medical implants.

Titanium is a commonly used biomaterial for dental and orthopaedic applications. To increase its ability to bond with bone, some attempts were made to coat its surface with calcium phosphate (CaP). This paper describes a new type of coating. Instead of a pure CaP layer, a mixing of titanium dioxide (TIO2) and CaP is fabricated and deposited as a coating. These layers are deposited by a sol-gel route on pure titanium substrates using various pre-treatments. The method consists of mixing a solution of tetrabutyl ortho-titanate or a sol of titanium dioxide with a solution of calcium nitrate and phosphorous esters. This composite is deposited on to commercially pure titanium plates, mechanically polished or blasted with pure crystalline aluminum oxide, using the spin-coating technique. These coatings are then fired at 650 or 850 degrees C for various times. The samples are characterized by X-ray diffraction for their crystallinity, X-ray photoelectron spectroscopy for their surface chemical composition and scanning electron microscopy for their topography. Samples treated at 850 degrees C present a well-pronounced crystallinity, and a high chemical purity at the surface. The topography is strongly related to the viscosity of the precursor and the substrate pre-treatment. Possibilities to structure the outermost layer are presented.

Journal Article↗