Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Mark T. Duffy is active.

Publication


Featured researches published by Mark T. Duffy.


Ophthalmic Plastic and Reconstructive Surgery | 2001

Exposure rates of wrapped and unwrapped orbital implants following enucleation

Tina Li; Joanne Shen; Mark T. Duffy

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.


Experimental Neurology | 1989

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

Brian M. Davis; Mark T. Duffy; Sidney B. Simpson

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)


Progress in Brain Research | 1994

Chapter 19 The lizard spinal cord: a model system for the study of spinal cord injury and repair

Sidney B. Simpson; Mark T. Duffy

Publisher Summary This chapter reviews studies on the lizard and comments on results from other systems, inframammalian and mammalian, as they relate to the findings in the lizard. In transection injuries, glial cells, often ependymal cells are the first to bridge the injury gap and they are responsible for guiding regenerating central nervous system (CNS) axons across the gap. This role of the glia, especially the ependymal epithelium, was first proposed based on studies of lizard cord regeneration. Subsequently the ependymal cells have been shown to guide regenerating CNS axons in larval anurans and in larval and adult urodeles during tail regeneration and during regeneration at thoracic levels in adult urodeles. The same role for the ependyma has also been demonstrated during tail regeneration in the fish, Sternarchus , and, although not explicitly stated, is suggested by descriptions of thoracic cord regeneration in the goldfish. In lizards and urodele amphibians, the ependymal cells fasciculate the outgrowing CNS axons into preformed longitudinal channels, while in larval anurans and the fish, Sternarchus, the ependymal cells form guidance channels in the form of grooves and gutters.


Ophthalmic Plastic and Reconstructive Surgery | 2001

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

Balaji K. Gupta; Deepak P. Edward; Mark T. Duffy

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.


Survey of Ophthalmology | 2003

Late Orbital Recurrence of a Choroidal Melanoma Following Internal Resection: Report of a Case and Review of the Literature

Nicholas Mittica; Geeta K. Vemuganti; Mark T. Duffy; Elise Torczynski; Deepak P. Edward

The management of uveal melanomas always has been a challenge to the clinicians and has evolved from the era of eye-removing surgeries to elimination of the tumor by the bodys own immune system through vaccines. Evaluating the outcome of each strategy improves our understanding of the disease process and helps us to improvise on the existing modalities of treatment. Internal resection of choroidal melanomas has been described as one of the treatment modalities for this malignant tumor. Tumor recurrences reported following this surgical procedure have been uncommon. We report a rare case of a 61-year-old Caucasian woman who presented with a 2-month history of progressive, painful proptosis in her right eye. Thirteen years ago she underwent internal resection of an intraocular choroidal melanoma in the same eye and had no evidence of metastatic disease. Magnetic resonance imaging demonstrated a mass occupying the superotemporal portion of the right orbit adjacent to the globe and behind the area of prior internal resection. Biopsy of the lesion and the subsequent A right orbital exenteration confirmed the diagnosis of recurrent malignant melanoma. Twenty-four months following exenteration the patient continues to be free of metastatic disease. Since internal surgical resection was described in 1984, this is the latest known recurrence of a posterior choroidal melanoma. In this review, we highlight the clinical features of this rare case and discuss in brief the rationale of various treatment modalities for choroidal melanoma.


Biomedical optics | 2004

Composites containing albumin protein or cyanoacrylate adhesives and biodegradable scaffolds: I. Acute wound closure study in a rat model

Grant T. Hoffman; Eric C. Soller; Douglas L. Heintzelman; Mark T. Duffy; Jeffrey N. Bloom; Travis M. Gilmour; Krista N. Gonnerman; Karen M. McNally-Heintzelman

Our Scaffold-Enhanced Biological Adhesive (SEBA) system was investigated as an alternative to sutures or adhesives alone for repair of wounds. Two scaffold materials were investigated: (i) a synthetic biodegradable material fabricated from poly(L-lactic-co-glycolic acid); and (ii) a biologic material, small intestinal submucosa, manufactured by Cook BioTech. Two adhesive materials were also investigated: (i) a biologic adhesive composed of 50%(w/v) bovine serum albumin solder and 0.5mg/ml indocyanine green dye mixed in deionized water, and activated with an 808-nm diode laser; and (ii) Ethicon’s Dermabond, a 2-octyl-cyanoacrylate. The tensile strength and time-to-failure of skin incisions repaired in vivo in a rat model were measured at seven days postoperative. Incisions closed by protein solder alone, by Dermabond alone, or by suture, were also tested for comparison. The tensile strength of repairs formed using the SEBA system were 50% to 65% stronger than repairs formed by suture or either adhesive alone, with significantly less variations within each experimental group (average standard deviations of 15% for SEBA versus 38% for suture and 28% for adhesive alone). In addition, the time-to-failure curves showed a longevity not previously seen with the suture or adhesive alone techniques. The SEBA system acts to keep the dermis in tight apposition during the critical early phase of wound healing when tissue gaps are bridged by scar and granulation tissue. It has the property of being more flexible than either of the adhesives alone and may allow the apposed edges to move in conjunction with each other as a unit for a longer period of time and over a greater range of stresses than adhesives alone. This permits more rapid healing and establishment of integrity since the microgaps between the dermis edges are significantly reduced. By the time the scaffolds are sloughed from the wound site, there is greater strength and healing than that produced by adhesive alone or by wounds following suture removal. This hypothesis is supported by the data of this study, as well as, the acute tensile strength data of Part I of this study.


Biomedical optics | 2004

A scaffold-enhanced light-activated surgical adhesive technique: surface selection for enhanced tensile strength in wound repair

Eric C. Soller; Grant T. Hoffman; Douglas L. Heintzelman; Mark T. Duffy; Jeffrey N. Bloom; Karen M. McNally-Heintzelman

An ex vivo study was conducted to determine the effect of the irregularity of the scaffold surface on the tensile strength of repairs formed using our Scaffold-Enhanced Biological Adhesive (SEBA). Two different scaffold materials were investigated: (i) a synthetic biodegradable material fabricated from poly(L-lactic-co-glycolic acid); and (ii) a biological material, small intestinal submucosa, manufactured by Cook BioTech. The scaffolds were doped with protein solder composed of 50%(w/v) bovine serum albumin solder and 0.5mg/ml indocyanine green dye mixed in deionized water, and activated with an 808-nm diode laser. The tensile strength of repairs performed on bovine thoracic aorta, liver, spleen, small intestine and lung, using the smooth and irregular surfaces of the above scaffold-enhanced materials were measured and the time-to-failure was recorded. The tensile strength of repairs formed using the irregular surfaces of the scaffolds were consistently higher than those formed using the smooth surfaces of the scaffolds. The largest difference was observed on repairs formed on the aorta and small intestine, where the repairs were, on average, 50% stronger using the irregular versus the smooth scaffold surfaces. In addition, the time-to-failure of repairs formed using the irregular surfaces of the scaffolds were between 50% and 100% longer than that achieved using the smooth surfaces of the scaffolds. It has previously been shown that distributing or dispersing the adhesive forces over the increased surface area of the scaffold, either smooth or irregular, produces stronger repairs than albumin solder alone. The increase in the absolute strength and longevity of repairs seen in this new study when the irregular surfaces of the scaffolds are used is thought to be due to the distribution of forces between the many independent micro-adhesions provided by the irregular surfaces.


Archive | 2004

Non-light activated adhesive composite, system, and methods of use thereof

Karen M. McNally-Heintzelman; Douglas L. Heintzelman; Jeffrey N. Bloom; Mark T. Duffy


The Journal of Comparative Neurology | 1990

Origin of spinal cord axons in the lizard regenerated tail: supernormal projections from local spinal neurons

Mark T. Duffy; Sidney B. Simpson; Diana R. Liebich; Brian M. Davis


The Journal of Comparative Neurology | 1992

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

Mark T. Duffy; Diana R. Liebich; Laurie K. Garner; Andrew Hawrych; Sidney B. Simpson; Brian M. Davis

Collaboration


Dive into the Mark T. Duffy's collaboration.

Top Co-Authors

Avatar

Jeffrey N. Bloom

University of Illinois at Chicago

View shared research outputs
Top Co-Authors

Avatar

Karen M. McNally-Heintzelman

Rose-Hulman Institute of Technology

View shared research outputs
Top Co-Authors

Avatar

Deepak P. Edward

Johns Hopkins University School of Medicine

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Eric C. Soller

Rose-Hulman Institute of Technology

View shared research outputs
Top Co-Authors

Avatar

Grant T. Hoffman

Rose-Hulman Institute of Technology

View shared research outputs
Top Co-Authors

Avatar

Sidney B. Simpson

University of Illinois at Chicago

View shared research outputs
Top Co-Authors

Avatar

Brian M. Davis

University of Illinois at Chicago

View shared research outputs
Top Co-Authors

Avatar

Bruce M. Buerk

University of Illinois at Chicago

View shared research outputs
Top Co-Authors

Avatar

Diana R. Liebich

University of Illinois at Chicago

View shared research outputs
Researchain Logo
Decentralizing Knowledge