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M T Duffy

Publications and source records attributed to M T Duffy.

13 recordsLinked to original sources
PubMed2001

2-Octyl cyanoacrylate tissue adhesive and muscle attachment to porous anophthalmic orbital implants.

PURPOSE: To investigate the tolerance and efficacy of a topical bioadhesive for direct muscle attachment to porous orbital motility implants. METHODS: Ten New Zealand White rabbits underwent unilateral enucleation with unwrapped 12-mm spherical porous implants placed into the muscle cone. Four animals received porous polyethylene implants and 6 received bone-derived hydroxyapatite implants. Small amounts of a bioadhesive (2-octyl cyanoacrylate) were applied to the underside of the muscles. Muscles were placed onto the desired location of the implant with pressure for 15 seconds. The conjunctiva was closed with a 6-0 plain gut suture, and the animals were observed for 6 weeks. At 6 weeks, animals were killed and the surgical orbit was exenterated. Orbits and implants were processed for histologic analysis. In addition, tensile strength testing of muscle-implant attachments was performed and compared with various other types of muscle-implant or muscle-sclera attachments. RESULTS: All cases resulted in integration of the muscles without slippage. All unwrapped hydroxyapatite implants (n = 6/6) had small anterior implant exposures without infection, significant inflammation, or exposure. No exposures were noted in porous polyethylene implants (n = 0/4). All implants were filled with fibrovascular tissue by 6 weeks. 2-Octyl cyanoacrylate yielded tensile strengths similar to that of sutured muscle coupling. CONCLUSIONS: 2-Octyl cyanoacrylate is well tolerated in the orbit, inducing minimal inflammation. It effectively attaches muscles to porous implants without hindering permanent integration or vascularization. The exposure rate for unwrapped hydroxyapatite spheres was not caused by the adhesive, as evidenced by the lack of exposures in the porous polyethylene implant group. 2-Octyl cyanoacrylate may be effective in reducing the cost and time for enucleation surgeries when porous motility implants are used.

Animals↗
PubMed2001

Exposure rates of wrapped and unwrapped orbital implants following enucleation.

PURPOSE: To compare the complication rate of porous polyethylene orbital motility implants with solid acrylic implants following enucleation and identify possible risk factors. METHODS: The authors retrospectively reviewed the charts of a total of 117 consecutive enucleations performed at the University of Illinois at Chicago between March 28, 1994, and May 28, 1999. Data obtained included patient demographics, surgical indication, implant type, attending surgeon, surgical technique, and any reported complications. The primary outcome was presence or absence of implant exposure at the final recorded visit. RESULTS: Of the 117 identified cases, 29 were eliminated due to insufficient follow-up data. Of the 88 remaining cases, 48 patients received porous implants and 40 received solid acrylic implants. Implant exposure developed in four cases. All exposures occurred in unwrapped porous polyethylene implants (n=2) or porous polyethylene implants wrapped in absorbable material (n=2). All exposures occurred in patients younger than 18 years of age, and 75% occurred early after trauma-associated enucleation surgery. CONCLUSIONS: The exposure rate of porous polyethylene implants in this study (9%) was found to be comparable to published rates for hydroxyapatite implants. There were no exposures of unwrapped solid acrylic spheres. Unwrapped porous implants in pediatric patients or following trauma-related enucleation may represent an increased risk for postoperative implant exposure. Absorbable wrapping of porous implants may carry the same risk for exposure as no wrapping. Porous implants wrapped in durable material appear to be as safe as solid acrylic spheres.

Adolescent↗
PubMed2000

Advances in lacrimal surgery.

For nearly a century the gold standard treatment for epiphora and nasolacrimal duct obstruction has been dacryocystorhinostomy (DCR). The definitive treatment of severe canalicular stricture remains conjunctivodacryocystorhinostomy. Although the high success rate of open external approaches continues to be confirmed in the literature, there have been promising advances for endocanalicular surgery and endonasal DCR. Despite a significant narrowing of the gap in outcomes, external DCR may hold the advantage in its ease of performance and lower economic impact. A minor controversy exists over the role of routine postoperative antibiotics. Intraoperative intravenous antibiotic dosing may be as effective as postoperative systemic antibiotics for patients at high risk of infection.

Catheterization↗
PubMed1999

Sclerosing sweat duct carcinoma of the eyelid margin: unusual presentation of a rare tumor.

OBJECTIVE: Sclerosing sweat duct carcinoma (SSDC) is a rare, slow-growing, locally invasive skin tumor of eccrine and pilar origin. It is usually located on the face, particularly the upper lip, cheek, and forehead. It has been infrequently reported on the eyelid, secondarily involved from adjacent cheek and brow tumors. Only four previous cases have reported primary eyelid tumors. The authors present four cases of primary eyelid margin involvement, which show the variability in clinical presentations. DESIGN: Retrospective case series. The authors present four case studies of lower eyelid margin tumors diagnosed as SSDC. PARTICIPANTS/METHODS: The history of this recently recognized neoplasm is discussed in relation to the cases presented and the role of the ophthalmologist and pathologist in such cases. RESULTS: Primary SSDC of the eyelid margin is a reportedly rare entity. This particular presentation can occur in all age groups; can mimic benign, acanthotic, or basal cell-like tumors; and is usually misdiagnosed initially. This can lead to a delay in definitive treatment for a tumor that classically presents late in its natural history to health professionals. All eight cases of primary eyelid SSDC now reported in the literature have occurred in the lower lid. CONCLUSION: This rare but aggressive tumor is difficult to diagnose from a simple biopsy and may be more common than previously believed. Initial or early diagnosis is important because of unusually invasive characteristics. Recurrence is common and usually leads to extensive tissue loss via direct invasion or subsequent wide resection. Correct histologic diagnosis at the time of initial tumor removal will likely aid in achieving complete excision with fewer recurrences.

Adult↗
PubMed1997

Infantile myofibromatosis of orbital bone. A case report with computed tomography, magnetic resonance imaging, and histologic findings.

OBJECTIVE: The authors report the clinical, radiographic, histologic, and surgical findings of a rare presentation of infantile myofibromatosis. A mass presenting at the inferolateral orbital rim of a 4-year-old child was imaged with both computed tomography (CT) and magnetic resonance imaging (MRI), excised surgically and analyzed histologically to confirm the diagnosis. Infantile myofibromatosis is a rare benign disorder of childhood consisting of well-demarcated nonencapsulated tumors. The overall prognosis depends on the number and location of tumors. Isolated infantile myofibromatosis of the head and neck is the most common form of this generally benign disease. DESIGN: A case review study is presented and discussed with regard to clinical, radiographic, histologic, and interventional findings. The literature is reviewed and the clinical relevance discussed. INTERVENTION: Surgical extirpation of the tumor was undertaken after sufficient localizing radiographic information was obtained. RESULTS: The tumor showed erosion of the orbital bone and orbital extension with reactive hyperostosis on CT imaging. The MRI finding showed an inhomogeneous well-demarcated dark mass on T1 images with increased signal intensity on T2 images. Gadolinium contrast showed significant vascular enhancement. Histologic sections showed a spindle-cell tumor of whorled myofibroblasts surrounding a hemangiopericytoma-like center. The tumor was excised completely. There has been no evidence of recurrence or adverse ocular sequelae in the first 6 months after surgery. CONCLUSIONS: Cases involving the orbit or cranial bones are particularly rare but can have profound secondary effects on local structures. Isolated tumors can occur in all age groups and can mimic more aggressive or malignant neoplasms. The CT and MRI findings are beneficial in establishing a differential diagnosis, plan of treatment, and prognosis. Early diagnosis is important to rule out other neoplasms. The appropriate treatment is excisional biopsy whenever possible and is considered curative. The authors present what to our knowledge is the first reported case of an isolated infantile myofibroma involving an orbital bone.

Child, Preschool↗
PubMed1992

Axonal sprouting and frank regeneration in the lizard tail spinal cord: correlation between changes in synaptic circuitry and axonal growth.

In our previous studies, we found that the number of supraspinal neurons projecting to the level of tail spinal cord increases by 74% during tail regeneration and that the number of local spinal neurons with descending projections increases 233%. However, only a small fraction of the supraspinal axons (less than 4%) and half of the local spinal axons actually enter the regenerated spinal cord. We suggested that this may be the result of "synaptic capture" in which regrowing axons make synapses on denervated targets rostral to the transection, aborting further regeneration. To examine this hypothesis, morphometric analysis of electron microscope (EM) photomontages was used to test for changes in synaptic distribution on ventral horn neurons rostral to regenerating tail spinal cord. In addition, 3H-thymidine and retrograde markers were used to determine whether the regenerate axons arose from cut axons, neurogenesis, or sprouting from uninjured neurons. 3H-thymidine injections during regeneration, combined with retrograde HRP pathway tracing, did not reveal the production of new neurons in the tail spinal cord. To test whether cut axons regenerate, fluorescein isothiocyanate conjugated latex beads were applied to the exposed end of the tail spinal cord. After tail regeneration, HRP was applied to the new spinal cord in the regenerated tail. Examination of local spinal neurons (the primary source of axons that enter the regenerated tail spinal cord) revealed that 28% of the neurons contained both labels. This indicated that cut axons successfully regrew into the new tail spinal cord. The regenerated axons that fail to enter the new tail spinal cord can be found in the normal spinal cord immediately rostral to the regenerated tail. To determine whether these axons were making synaptic contacts, lamina IX ventral horn neurons were examined. EM photomontages of the spinal cord rostral to the regenerate tail revealed the following properties: (1) neurons rostral to regenerated tails are larger in area compare to non-regenerates (mean increase = 112%); (2) axosomatic contacts cover a greater percentage of the neuronal soma following regeneration compared to normal (mean increase = 23%); and (3) this increased innervation is the result of an increase in the number of synaptic boutons rather than larger boutons. The number of synaptic contacts in regenerated lizards returned to normal following lumbar transection, indicating that supraspinal and/or long descending propriospinal afferents were the major source of the increased synaptic contacts.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1989

Bulbospinal and intraspinal connections in normal and regenerated salamander spinal cord.

The salamander is the only limbed adult vertebrate which can regenerate portions of cervical, thoracic, or lumbar spinal cord. While the salamander has been a popular model for regeneration of the spinal cord, it is still not known what portions of the nervous system participate in the regeneration process. In the experiments reported here we examine the bulbospinal and intraspinal projections to the lumbar spinal cord in normal and regenerated salamanders (Notophthalmus viridescens). HRP application to the lumbar enlargement of normal salamanders labeled cells in the ventral thalamus, the rostral tegmentum in the proposed homolog of the red nucleus, the reticular neurons of the rhombencephalon, and the midline regions of the rhombencephalon which are possibly equivalent to raphe nuclei of other vertebrates. In the brachial spinal cord HRP-labeled cells were located in dorsal, intermediate, and ventral regions of the spinal gray matter and tended to be located at the periphery of the gray matter. To examine the spinal circuitry of regenerated salamanders, animals received complete spinal transections at the junction of the thoracic and lumbar spinal cord, abolishing all spontaneous coordinated hindlimb and tail movements. Animals exhibited walking and swimming within 60 days at which time a pledget of HRP was inserted into a gap in the spinal cord made by a transection 10.0 mm (six animals) or 5.0 mm (one animal) caudal to the first lesion. On average, the number of HRP labeled brain stem neurons in regenerated animals was 40% of that found in normal animals. The number of labeled cells in the brachial spinal cord was within the range of normal animals.(ABSTRACT TRUNCATED AT 250 WORDS)

Amputation, Surgical↗
PubMed1989

Reconstruction of the mandibular condyle using ramus osteotomies: a preliminary report.

Reconstruction is required for a number of conditions in which condylar bone is lost resulting in dental and skeletal change. Ramus osteotomies are described as an alternative to the currently used methods. Four cases are described to illustrate the use of this technique. These osteotomies have several advantages over other methods and have the potential for better functional results.

Adult↗
PubMed1988

Simultaneous measurement of luteinizing hormone (LH)-releasing hormone, LH, and follicle-stimulating hormone release in intact and short-term castrate rats.

The temporal relationship between LHRH release and gonadotropin secretion as well as the effects of castration on LHRH release were investigated in conscious, freely moving male rats. LHRH release was measured in hypothalamic/median eminence perfusates, while levels of pituitary gonadotropins (LH, FSH) were determined in sequential blood samples obtained via atrial catheters. Twenty-four to 26 h before experiments, rats underwent sham surgery or castration. LHRH release in push-pull perfusates from both groups was pulsatile, and nearly all identified LH pulses (83.3%) were temporally associated with LHRH pulses. Of the fewer irregular FSH pulses that were observed, only 43.7% were temporally associated with LHRH pulses. Mean LHRH pulse amplitude and mean LHRH levels were not different in intact and castrate animals. The frequency of LHRH pulses was moderately increased in castrate rats (1.30 pulses/h) compared to that in intact animals (0.83 pulses/h), and this acceleration was accompanied by a significant increase in LH pulse frequency, pulse amplitude, and mean level. It was also noted that the number of silent LHRH pulses (those not associated with LH pulses) was dramatically reduced in castrate animals. Characteristics of gonadotropin release (pulse frequency, pulse amplitude, and mean level) were not significantly different in animals undergoing push-pull perfusion/bleeding procedures from those in rats not receiving push-pull cannula implants. We conclude from these studies that 1) LH pulses show a high concordance with LHRH pulses, providing evidence that the LHRH pulse generator operates as the neural determinant of LH pulses in male rats, 2) FSH secretion is not associated with LHRH release in an obvious and consistent manner, suggesting that LHRH/FSH relationships are not easily discerned in these animals or that a FSH-releasing factor distinct from the LHRH decapeptide may regulate FSH secretion, 3) a modest increase in LHRH pulse frequency occurs 24-30 h after castration, and 4) silent LHRH pulses occur with much greater regularity in intact than in castrate rats. The latter two observations suggest that both hypothalamic and intrapituitary sequelae of castration may be critically important in the development of postcastration increases in LH secretion and the negative feedback of gonadal steroids.

Animals↗