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Biomedical subjects

C R Pelletier

Publications and source records attributed to C R Pelletier.

12 recordsLinked to original sources
PubMed1999

A new variety of hydroxyapatite: the Chinese implant.

PURPOSE: This study was designed to evaluate a new type of hydroxyapatite (HA) implant (produced in China) in a rabbit model. METHODS: Three New Zealand white rabbits underwent enucleation of one eye followed by implantation of a 12-mm Chinese HA implant wrapped in Vicryl mesh (polyglactin 910). Magnetic resonance imaging was performed to assess host fibrovascularization of the implant 4, 8, and 12 weeks after implantation. One animal was sacrificed at each of these times for histopathologic examination. The Chinese implant was also examined chemically and by scanning electron microscopy. It was compared to the original BioEye and the third generation synthetic HA implant produced in France by FCI (FCI3). RESULTS: This new variety of HA implant from China is heavier than the FCI3 implant but lighter than the original BioEye. The Chinese implant was easy to work with and not fragile. The pore size was more uniform than the FCI3 implant and similar to the BioEye implant clinically and by scanning electron microscopy. The pores in this implant are unidirectional. Analysis for impurities revealed a calcium oxide (CaO) content of 4.4%. Histopathologically, central vascularization occurred by 4 weeks and was similar in extent to the vascularization seen with the FCI3 implant and the BioEye. CONCLUSIONS: The Chinese implant is less expensive then the BioEye and the FCI3 implants, and appears to be a viable alternative to the BioEye. Further refinements are in progress to eliminate the CaO contaminant.

Animals↗
PubMed1999

Bilateral eyelid edema: an uncommon presentation of Rosai-Dorfman disease.

PURPOSE: Rosai-Dorfman disease (sinus histiocytosis with massive lymphadenopathy) is a rare entity with ophthalmic manifestations in 11% of patients. Orbital and eyelid involvement as the presenting features is even more unusual. METHODS: The authors report the clinical findings of a 41-year-old man with Rosai-Dorfman disease presenting as eyelid edema. Biopsy of the involved tissue was analyzed by light microscopy. RESULTS: Histologically the orbicularis muscle contained a patchy infiltrate of lymphocytes, plasma cells, and large pale histiocytes. The histiocytes had lymphocytes within them, a condition referred to as lymphocytophagocytosis. CONCLUSIONS: Rosai-Dorfman disease is a rare clinical entity that may occasionally manifest with eyelid edema. Biopsy reveals a characteristic histopathologic picture.

Adult↗
PubMed1998

Use of temporalis fascia for exposed hydroxyapatite orbital implants.

The hydroxyapatite implant (Bio-Eye, Intergrated Orbital Implant, Inc., San Diego, CA, U.S.A.) has gained increasing popularity as an orbital implant in recent years. Several complications may occur, including infection, exposure, extrusion, and various peg problems. Exposure of the implant appears to be the most common complication, ranging up to 21.6%. Many techniques, including nonsurgical and surgical approaches, have been described to manage these exposures. When surgery is indicated, a patch graft may be required to cover the defect. We report our experience and technique with autogenous temporalis fascia as a patch graft. Autografts such as temporalis fascia are easily obtained, bring about no immunological reaction, and have no risk of infectious transmission.

Adult↗
PubMed1998

An unusual complication associated with hard palate mucosal grafts: presumed minor salivary gland secretion.

Hard palate grafts are commonly used in eyelid reconstructive procedures as a replacement for posterior lamellar defects. Four patients are presented with an unusual complication after placement of a hard palate graft: presumed minor salivary gland secretion. They were experiencing stringy mucous discharge over the graft and along the eyelids, causing visual blurring. Removal of the graft in one patient and cryotherapy to the grafts in the others (presumably causing atrophy of the minor salivary gland tissue found within the grafts) allowed resolution of symptoms. The authors propose the application of cryotherapy to the graft surface to atrophy the salivary glands, prevent any further production of mucus, and return the tear film to a more normal consistency. Alternatively, surgical removal of the grafts can be performed. To our knowledge, this complication (saliva-like mucoid discharge) has not been previously reported.

Adult↗
PubMed1998

Assessment of ocular trauma associated with head and neck injuries.

We reviewed the real and potential ocular problems in all head and neck injuries at a tertiary care and regional trauma center from April of 1994 to March of 1995. Through a retrospective study, 127 charts were reviewed, specifically looking at the mechanism of injury, types of injury, whether there was any ocular trauma noted in the chart, and whether there was a consultation to the ophthalmology department. Forty-one of these patients were seen by an ophthalmologist as the initial consultant for ocular and orbital injuries recognized by the emergency staff. In the 86 remaining patients, signs of potential ocular injury were recorded in the chart in 62 (72%) of these patients, yet an ophthalmology consultation was requested for only 23 of them (37%). This survey reveals the lack of awareness in a regional trauma center of certain ocular and periocular signs that may be indicative of more serious ocular injuries. It is the purpose of this article to highlight these concerns to the various health professionals involved with head and neck trauma patients in the hope that the patients will, in the end, benefit from a more thorough and complete assessment of the potential ocular and periocular injuries.

Adolescent↗
PubMed1991

Effect of direct injection of cyclosporine on the arterial vessels of the isolated hind limb in the dog.

Cyclosporine's toxic side effects are widely recognized as a cause of major morbidity. Peripheral vasoconstriction has been suggested as the pathophysiological mechanism for hypertension and renal failure caused by cyclosporine. To study vascular effects on peripheral arterial circulation, cyclosporine was injected into isolated hind limbs perfused at constant flow in the dog. Pure powder cyclosporine was dissolved in a 10% fat emulsion and infused directly into the arterial inflow of the perfused hind limb (n = 7) at a concentration of 5 mg/kg body weight. Reactivity of the vascular bed was first shown by an average decrease of 72 +/- 4 mmHg (95% confidence interval 63 to 81, P less than 0.01) in hind limb perfusion pressure after infusion of 5 mg nitroglycerin. Infusion of fat emulsion did not cause any significant changes. The infusion of cyclosporine caused an average increase of 29 +/- 5 mmHg (95% confidence interval 17 to 41, P less than 0.01) in hind limb perfusion pressure after 4 mins' infusion. After cyclosporine infusion, the vascular bed still responded to nitroglycerin by an average decrease of 56 +/- 5 mmHg (95% confidence interval 42 to 69, P less than 0.01) in perfusion pressure. Blockade of alpha-receptors with phentolamine in five dogs and ipsilateral lumbar sympathectomy in four prevented the increase in perfusion pressure following cyclosporine injection. In conclusion, cyclosporine injected at high doses causes a small vasoconstriction of the peripheral arterial circulation in the hind limb through stimulation of alpha-adrenergic receptors mediated by the sympathetic nervous system. Since the response is completely abolished by sympathectomy, it is probably caused by reflex activation. A direct effect of cyclosporine on the arterial vessel walls of the limb can therefore be excluded.

Animals↗