Search PubMed⌕ Search

Biomedical subjects

R Casanova

Publications and source records attributed to R Casanova.

At least 19 recordsLinked to original sources
PubMed1998

Tissue engineered neocartilage using plasma derived polymer substrates and chondrocytes.

This study demonstrates that fibrin monomers can be polymerized into moldable gels and used for the encapsulation of isolated chondrocytes. This biologically derived scaffold will maintain three-dimensional spatial support, allowing new tissue development in a subcutaneous space. Chondrocytes isolated from the glenohumeral and humeroradioulnar joints of a calf were combined with cyroprecipitate and polymerized with bovine thrombin to create a fibrin glue gel with a final cell density of 12.5 x 10(6) cells/ml. The polymer-chondrocyte constructs were implanted subcutaneously in 12 nude mice and incubated for 6 and 12 weeks in vivo. Histologic and biochemical analysis including deoxyribonucleic acid (DNA) and glycosaminoglycan quantitation confirmed the presence of actively proliferating chondrocytes with production of a well-formed cartilaginous matrix in the transplanted samples. Control specimens from 12 implantation sites consisting of chondrocytes alone or fibrin glue substrates did not demonstrate any gross or histologic evidence of neocartilage formation. Moldable autogenous fibrin glue polymer systems have a potential to serve as alternatives to current proprietary polymer systems used for tissue engineering cartilage as well as autogenous grafts and alloplastic materials used for facial skeletal and soft-tissue augmentation.

Animals↗
PubMed1996

Surgical model to assess the effects and optimal timing of craniofacial fixation.

An in utero swine model of craniofacial deformity was developed as a potential alternative to neonatal models currently used for evaluating the optimal timing and long-term effects of rigid fixation techniques on a growing cranium. At 75% gestation, seven fetal piglets were randomly selected to undergo periosteal stripping of frontal and parietal bone segments with and without extensive coronal suture fusion procedures with cyanoacrylate adhesive. Fetal swine were killed postpartum at 4 and 11 weeks after fusion to assess craniofacial deformity. Piglets undergoing coronal fusion had slight deviation of the nose-snout toward the side of fusion and taller cranial vaults. The vertical cranial index of the experimental fusion group was 0.34 in comparison to a vertical index of 0.27 for the controls, suggesting abnormal vertical height expansion. There was no difference in the horizontal cranial index of either control or experimental fusion groups. Neither sows nor piglets were lost to anesthetic complications, uterine sepsis, or preterm labor during the initial laparotomy or subsequent cesarean delivery.

Animals↗
PubMed1996

Injectable cartilage using polyethylene oxide polymer substrates.

This study demonstrates that polyethylene oxide gels, which are biocompatible and biodegradable synthetic polymers, can be utilized for the encapsulation of isolated chondrocytes and maintenance of three-dimensional spatial support for new tissue development. Chondrocytes isolated from the glenohumeral and humeroradioulnar joints of a calf were added to a 20% polyethylene oxide solution in Ham's F-12 medium to generate a final cellular density of 10 x 10(6)/mL. The polymer-chondrocyte constructs were injected through a 22-gauge needle in 500-microliters aliquots subcutaneously in 12 nude mice and incubated for 6 and 12 weeks in vivo. Histologic and biochemical analyses including deoxyribonucleic acid and glycosaminoglycan quantitative analyses confirmed the presence of actively proliferating chondrocytes with production of a well-formed cartilaginous matrix in the transplanted samples. Control specimens from eight implantation sites consisting of chondrocytes alone or polyethylene oxide substrates did not demonstrate any gross or histologic evidence of neocartilage formation. These findings demonstrate the potential use of an injectable and moldable polymer substrate that can support cell proliferation and matrix synthesis after subcutaneous transplantation for neocartilage generation. The use of functional biologic tissue substitutes may serve as an alternative solution to current methods of augmentation or reconstruction of structural craniofacial contour deformities.

Animals↗
PubMed1995

Porous polyethylene implant for orbital wall reconstruction.

Short-term and intermediate-term results from clinical use of high-density porous polyethylene implants for reconstructive orbital surgery have been encouraging. This article presents an intermediate-term result from one institution with a comprehensive comparative analysis of other available alloplastic materials. A patient survey of 32 cases of orbital reconstruction using porous polyethylene sheet implants was performed, with a mean follow-up period of 32 months (range 15 to 67). All cases were trauma-related injuries. The result was compared with that of published reports of other alloplastic materials with specific emphasis on complication rates. Complication rate following the use of porous polyethylene sheet implants was 6%. This finding was consistent with those of other reports on porous polyethylene sheet implants. A consistent, satisfactory surgical outcome and low complication rate were observed. In the authors' review, the porous polyethylene implants compared favorably in a comparative analysis of other alloplastic materials.

Adolescent↗
PubMed1992

Dose and test for dipyridamole infusion and cardiac imaging early after uncomplicated acute myocardial infarction.

To evaluate the relation of the dose of intravenous dipyridamole on results of thallium and echocardiographic testing, the results of standard- (0.56 mg/kg/4 minutes) versus high- (0.84 mg/kg/10 minutes) dose dipyridamole were obtained 9 +/- 3 days after uncomplicated acute myocardial infarction in 57 patients. New wall motion abnormalities were compared with redistribution of thallium imaging and results of discharge coronary angiography. The sensitivity of thallium in predicting the presence of multivessel coronary artery disease was significantly (p < 0.01) higher (85%) than echocardiography (53%) and was unaffected by the dose. However the sensitivity of echocardiography was better with the higher dose (53 vs 14%). Minor adverse effects occurred in 34 patients (59%) after receiving the high dose and only in 4 patients (7%) after the standard dose (p < 0.001). Thus, thallium-201 scintigraphy during standard-dose dipyridamole infusion is more effective than high-dose dipyridamole echocardiographic testing in safely identifying patients who could benefit from early invasive evaluation and therapy.

Angina Pectoris↗
PubMed1992

[Management and prognosis of acute myocardial infarct in advanced age: comparison of the cardiac intensive care unit and the cardiology ward].

The aim of this prospective study was to assess the prognostic and most suitable management of AMI in elderly patients (age > or = 75 years). From September 1988 to August 1991, 129 such patients (pts) were evaluated: 35 (27%) were admitted to CCU because of arrhythmias or severe hemodynamic complications; 94 (73%) were addressed, according to bed availability, to CCU (55 pts) or Cardiology Ward (39 pts), where all patients underwent continuous ECG monitoring for at least 72 hours. Age, gender, history of previous angina or myocardial infarction, presence of chest pain or ECG ischemia on admission, site and extent of AMI, delay on admission, CPK-MB peak, recurrent angina, arrhythmias, heart failure, emotional disorders, hospital mortality and length of hospital stay were compared. Our results show that elderly patients who suffered from complicated AMI were at high risk for death and severe in-hospital complications. No significant prognostic differences were observed between the two groups with uncomplicated AMI. Thus hospitalization in the Cardiology Ward seems to be valuable, safe and well tolerated in our population of elderly patients with AMI, and without initial complications.

Age Factors↗
PubMed1991

[Biological indicators of bacterial infection in newborn infants].

Biological markers of neonatal bacterial infection are useful if they bring early indications and if they are sensitive and specific. There are two kinds of tests: hematological signs and acute phase proteins. The most specific hematological signs are, in chronological order: leuconeutropenia--myelemia--neutrophilic polynucleosis. Gestational and post-natal ages have to be taken in consideration for correct interpretation of white cell count and differential. Several acute phase proteins increase in infected newborns: fibrinogen, C reactive protein, orosomucoïd. If determined quantitatively, C reactive protein is a sensitive, specific and early marker allowing, in addition, to follow the reaction to treatment: the return to normal range of CRP and later of orosomucoïd attest for recovery. These biological tests have to be sequentially determined during the first days in order to obtain a maximal information.

Aging↗
PubMed1991

Transcranial Doppler evaluation of cerebral infarction in the neonate.

We recorded cerebral artery flow velocities (CAFV) in two neonates with cerebral infarction, using transcranial Doppler sonography (TCD). Cerebral infarction was diagnosed by brain imaging. The arteries investigated were the middle cerebral artery (MCA), the internal carotid artery (ICA) and the anterior cerebral artery (ACA). The whole territory of right MCA was involved. A decrease in CAFV was noted in MCA and ICA of the affected side. Furthermore, early recordings of CAFV allowed us to distinguish perinatal infarction from antenatal infarction: in the former, Doppler signal was completely absent during the first days of life whereas in the latter, Doppler signal was reduced but present. The process of recanalization could be followed. The asymmetry of CAFV recorded in the neonatal period seems to persist definitively at least in MCA. These Doppler data correlate well with the evolutive stages of cerebral infarction shown by brain imaging. Beside US, CT and MRI scans, TCD may be a useful adjunct for identifying and following infants with suspected occlusion of major cerebral vessels.

Blood Flow Velocity↗
PubMed1991

[Thallium and echo- dipyridamole in the early selection of patients at risk after acute myocardial infarction. Which test? What dose?].

UNLABELLED: The optimal iv dose of Dipyridamole (Dip) in echocardiography (echo) or Thallium scintigraphy (Tl) remains undetermined. To select the high-risk patients (pts) subset, we performed echo and Tl with standard dose (SD) and high dose (HD) Dip infusion (0.56 mg/Kg/4'-0.84 mg/Kg/10' respectively) in 40 pts 9 +/- 3 days after admission for acute myocardial infarction (AMI). Of these, 38 pts had coronary artery disease at angiography and 2 had no significant lesions. Worsening in regional wall motion on echo and reversible perfusion defects on Tl were considered abnormal patterns. SD had no side effects; only in one pt was ischemic ventricular dysfunction detected on echo, whereas Tl redistribution was found in 24 pts (12 had multivessel disease and 12 had one coronary stenosis greater than or equal to 70%). HD caused adverse reaction in 24 pts, did not enhance SD-Tl sensitivity, but induced abnormal echo in 18/24 pts with transient defects on SD-Tl. Eleven of the 16 Tl negative pts had occlusive disease, 3 had one vessel disease and 2 showed no evidence of coronary artery disease. IN CONCLUSION: SD is safe but often provokes a submaximal coronary vasodilation. Failure to detect ischemia on echo may be explained by this. SD-Tl is, however, able to identify high-risk pts who may benefit from early myocardial revascularization. HD does not enhance SD-Tl sensitivity, but it is necessary to induce echo abnormalities which are all too often undetectable at SD.

Adult↗
PubMed1990

[Contribution of transcranial Doppler sonography to the diagnosis of brain death in children].

Brain death can be characterized by cessation of cerebral blood flow. We have measured blood flow velocity in cerebral arteries of 17 comatous children with a transcranial pulsed Doppler equipment. In 11 children who progressed to brain death, we have recorded a progressive decrease of Doppler signal with the following steps: decrease of diastolic velocity, no diastolic velocity, reverse diastolic flow, decrease of systolic signal, no signal at all. In the 6 surviving children (all except one with severe deficits), after an initial reduction but never to a retrograde flow, arterial cerebral blood flow velocity increased to high diastolic values before normalization. Transcranial Doppler technique is non invasive, reliable, can be used at the bedside and repeated; it allows evaluating the cerebral blood flow in comatous children and represents a useful adjunct to brain death diagnosis.

Brain Death↗
PubMed1990

Response of patients with hemophilia A and von Willebrand disease to desmopressin (DDAVP).

Factor VIII (FVIII) response to desmopressin (deamino-8-D-arginine vasopressin, abbreviated DDAVP) was studied in patients with mild Hemophilia A and von Willebrand Disease (vWD) who attend our Hemophilia Clinic. Thirty eight children and 9 adults had their F VIII components assayed 60 minutes after intravenous (IV) administration of DDAVP, 0.35 microgram/kg. Among 27 hemophiliacs, F VIII coagulant activity (F VIII: C) increased from a mean of 16.8 to 59.2 u/dL; with an average 3.2-fold increase. In 20 vWD patients, the mean F VIII:C and von Willebrand Factor increased from a mean of 50.1 to 136%; and from 22.6 to 75.6%; with an average 3.0 and 5.7-fold increase, respectively. The overall F VIII:C response was good or excellent in 81.5% of the hemophiliacs, and in 89.5% of the vWD patients tested. No significant side effects were observed. This study has demonstrated that IV DDAVP can cause an increase of F VIII:C and vWF to hemostatic levels, and thus it may be useful for the control of bleeding episodes in most of the patients tested in our clinic.

Adult↗