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Biomedical subjects

R F Morgan

Publications and source records attributed to R F Morgan.

At least 37 records · Page 2Linked to original sources
PubMed1995

In utero brachial artery thrombosis: limb salvage with postnatal urokinase infusion.

In utero brachial artery thrombosis leading to neonatal extremity gangrene can occur from a variety of causes. Traditional management has been limited to supportive care, often leading to early amputation. We report a case of a 1-day-old neonate who presented with an in utero brachial artery thrombosis and whose treatment consisted of early, aggressive systemic thrombolytic therapy followed by serial soft-tissue debridement and ultimate skin coverage through cultured epithelial autografts. This resulted in a successfully salvaged and partially functional upper extremity.

Arm↗
PubMed1995

A rapid in vitro assay of cellular chemomigration in an epithelial carcinoma cell line.

We have studied the chemomigration activity of an epithelial carcinoma cell line using a modified 96-well Boyden chamber apparatus consisting of upper and lower wells separated by an 8-microns pore polycarbonate filter. Cells from the malignant squamous carcinoma cell line A-431 were plated in the upper wells over a collagen IV-coated filter. In chemokinesis assays, the cells were allowed to migrate toward NIH 3T3 fibroblast-conditioned medium or control media in the lower wells for 6 hours at 37 degrees C with 10% CO2. A-431 cells preferentially migrate across the barrier toward conditioned media but not control media. Control normal keratinocytes showed no migration. A highly metastatic melanoma cell line and poorly metastatic melanoma cell line, in which chemomigration has been shown previously to correlate with metastatic potential, were used as positive and negative cellular controls. This system provides a rapidly quantifiable method by which the invasion characteristics of multiple cell lines can be studied simultaneously in a single assay using the 96-well format.

3T3 Cells↗
PubMed1995

Comparison of topical fibrin glue, fibrinogen, and thrombin in preventing seroma formation in a rat model.

Fibrin glue has been shown to decrease seroma formation in animal models. To further delineate this mechanism, the efficacy of fibrin glue was compared to topical fibrinogen and thrombin in preventing postoperative seromas. A model consistently producing seromas was developed by bilateral neck dissection, lymphadenectomy, and submandibular sialoadenectomy in the Sprague-Dawley rat. Groups of 20 rats underwent this procedure and were blindly treated with either fibrin glue, fibrinogen, thrombin, or saline control. Necropsy on postoperative day 5 revealed a statistically significant (chi-squared) decrease in seroma incidence using fibrin glue (0%) and fibrinogen (15%), while thrombin (95%) and saline (100%) were ineffective in preventing seromas. The use of fibrin glue and fibrinogen in this role merits further investigation.

Animals↗
PubMed1995

A portable tensiometer for assessing knot-tying technique.

The purpose of this study was to determine the influence of orthopedic surgeons' tying techniques on knot security using 2-0 and 4-0 monofilament and multifilament nylon sutures. Using an Instron Tensile Tester and a portable tensiometer, knot security was achieved with these sutures using four-throw square knots (1 = 1 = 1 = 1). After didactic and psychomotor skill training, medical students were taught to construct the four-throw square knot using either a two-hand tie or an instrument tie. Using the portable tensiometer, their knot-tying techniques were judged to be superior to those used by orthopedic surgeons. The orthopedic surgeon's faculty technique can easily be corrected by didactic information and psychomotor skill training.

Clinical Competence↗
PubMed1995

New instruments, bone liners, and tray for finger joint arthroplasty.

Titanium circumferential grommets have been developed for finger joint arthroplasty that fit on the base of the silicone implant stems to protect the flexible hinge from tearing and fracture. To facilitate grommet insertion, new intramedullary bone rasps have been devised with a reverse cutting tooth pattern, an extended shaft for an improved view of the surgical field, and a redesigned cutting head to allow for grommet insertion. Surgical accessibility and ease of recognition have been facilitated by the development of color-coded sizers. All of the instruments necessary for finger joint surgery are available in a molded tray that has also been redesigned with a transparent lid and clearly labeled compartments for accurate determination of instruments and implant sizers.

Equipment Design↗
PubMed1994

Age and tolerance to secondary ischemia in rat epigastric flaps.

The use of microvascular procedures is increasing as the population continues to age. The purpose of this study was to observe the survival of skin flaps after ischemic injury. Skin flaps (n = 50) underwent either 3 hours of primary (1 degree) or secondary (2 degrees) venous occlusion in young (2-3 mo) and old (18-22 mo) rats. Skin flap survival was assessed on postoperative day 7. Survival rates for young and old after 3 hours of 1 degree ischemia was 100% and 90% (ns). Survival rats for young and old after 2 degrees ischemia were 67% and 47% (ns).

Aging↗
PubMed1994

Biomechanical performance of a disposable graft stapler with absorbable skin tacs.

A stapler has been specially designed for fixing skin grafts to the underlying wound. The stapler has a loading unit which can be reloaded with cartridges of absorbable tacs. Each tac is made of a polymer which is biocompatible with tissue. The stapler ejects the tac into the graft, reliably securing it to the underlying tissue. The force and work required to eject the tacs were significantly less than that needed to form the metal staples. The most obvious advantage of the tac is that the majority of the tacs spontaneously extrude after the first dressing change. The performance of the disposable graft stapler with absorbable skin tacs has been compared to that of the disposable skin stapler with metal staples.

Biocompatible Materials↗
PubMed1994

Magnetic resonance imaging of in situ mammary prostheses.

A study was conducted at the University of Virginia Health Sciences Center to examine the effectiveness of magnetic resonance imaging in detecting rupture or deflation of in situ mammary prostheses. Thirty-three women with 59 prostheses were included in the study. Fifteen of the 33 patients had undergone surgery for removal or replacement of 21 implants. Positive findings for rupture were accurately predicted for 15 implants and confirmed at surgery. Negative findings for rupture were accurately predicted in the remaining 6 implants and confirmed at surgery. Although it is a more costly procedure than either mammography or ultrasonography, we believe that magnetic resonance imaging is also more accurate in detecting damaged implants, particularly when they are contained within an intact capsule or when the implants are stacked. Unlike mammography, magnetic resonance imaging requires no ionizing radiation or breast compression. Magnetic resonance imaging of the in situ breast prosthesis may be a useful adjunct when other modalities yield inconclusive results or when a contained rupture is suspected.

Adolescent↗
PubMed1994

Thomas Dent Mutter, MD: early reparative surgeon.

Thomas Dent Mutter (1811-1859) was one of the early American pioneers of plastic surgery. He studied under some of the great teachers in Europe during the early 19th century and returned to the United States as a professor of surgery at Thomas Jefferson University in Philadelphia. He was renowned for his operations on clubfoot, cleft lip and palate, congenital anomalies, and mutilating injuries. He is best known for the cervical flap that bears his name. His contributions include an endowment for a medical museum that bears his name to which he donated a large collection of his medical specimens. The Mutter Museum prospers to this day. His ideas and innovations have influenced many students of plastic surgery both during his lifetime and today.

History, 19th Century↗
PubMed1994

MR imaging of breast implants.

Magnetic resonance (MR) images of 57 implants in 32 women were reviewed for possible complications. Spin-echo T2-weighted MR imaging of one or both breasts was performed with dedicated breast coils in axial, coronal, and sagittal planes. At surgery in 19 patients, MR evaluation for rupture correlated in 17 cases (two false-negative ruptures). Implant ruptures were seen at surgery in 15 of the 19 patients. Nine ruptures involved single-lumen implants: Six were ruptured within the fibrous capsule that normally forms around the foreign implant (intracapsular rupture [two were seen only at surgery]), and three were ruptured beyond this fibrous capsule into the soft tissues (extracapsular rupture). Five ruptures involved double-lumen implants, in which only the outer lumen had ruptured, and one involved a single-lumen saline implant that had completely collapsed. Additional complications of capsule formation and infection were suggested in two implants, and infection was suggested in one. The MR imaging appearances of the various types of implants as well as their complications are presented.

Adolescent↗
PubMed1994

Dimethyl sulfoxide increases the survival of primarily ischemic island skin flaps.

There is ample evidence of the involvement of free radicals in mediating skin flap necrosis. Dimethyl sulfoxide (DMSO) is a well-tolerated, safe drug that is a powerful scavenger of the hydroxyl free radical. The current study investigated the effect of DMSO on the survival of 9 x 4 cm skin flaps based on the epigastric vessels subjected to primary venous occlusion. Forty-seven skin flaps were elevated and the epigastric vein was occluded by a microvascular clamp for 8 hours. Group 1 received DMSO (1.5 gm/kg) intraperitoneally at reperfusion. Group 2 received saline solution, group 3 received DMSO at reperfusion and every day for 5 days, group 4 received DMSO preoperatively and then as in group 3, and group 5 was the saline solution control for groups 3 and 4. DMSO did not increase percent flap survival when given as a single dose at reperfusion (40.6% +/- 42.7%) compared with saline solution (33.7% +/- 41.2%). When DMSO was continued in the postoperative period, group 3 (86.2% +/- 25.8%) and group 4 (78.0% +/- 32.5%) had significantly better survival than the saline solution control group (32.6% +/- 39.8%) (p < 0.01 and p < 0.03, respectively). There was no significant difference between groups 3 and 4. DMSO administered at reperfusion and postoperatively for 5 days significantly increased flap survival. It is hypothesized that this occurs through scavenging deleterious free radical species. This effect may have clinical significance.

Animals↗
PubMed1994

A new device for securing meshed split-thickness skin grafts.

This report describes the design, operation, and biomechanical performance of the Auto Suture Multifire Graftac-S disposable surgical staplers and absorbable tacks. The performance of this reloadable stapler has been compared to that of the Auto Suture Multifire Premium disposable skin stapler. The Premium stapler forms stainless steel staples to close the wound. The Graftac-S ejects absorbable tacks into the graft from a cartridge, which can be reloaded during a single operation. In two clinical trials of 10 patients each, the Graftac-S delivered absorbable tacks which were biocompatible and successfully secured the graft to the wound. The most obvious advantage of this device is that it obviates the need to remove the staples from the wound later. By the tenth postoperative day, about 90% of the tacks had extruded spontaneously, thereby reducing the amount of postoperative care required; discomfort to the patient during removal of the stainless steel staples is eliminated.

Biocompatible Materials↗
PubMed1993

Verapamil enhances the survival of primary ischemic venous obstructed rodent skin flaps.

The effect of verapamil, a calcium channel blocker, on the survival of skin flaps subjected to primary venous obstruction was studied. Skin flaps 9 x 4 cm, which are axial patterns with random extension, were elevated in Sprague-Dawley rats. A microvascular clamp was placed on the vein alone for 8 hours. Group 1 received verapamil (0.3 mg/kg) before flap elevation and before clamp release; group 2 received saline on the same schedule. Group 3 received verapamil (0.3 mg/kg) as above, plus every 8 hours for 5 days postoperatively. Group 4 received saline on the same schedule. There was no difference in survival between groups 1 and 2. Group 3 had 100% improvement in the flap survival compared with group 4 (78% vs 37%). Verapamil, if administered for the duration of the experiment, significantly increased flap survival.

Abdomen↗
PubMed1993

Biomechanical performance of new vascular sutures and needles for use in polytetrafluoroethylene grafts.

Two new cardiovascular monofilament sutures attached to taper point needles have been developed for use in expanded polytetrafluoroethylene (PTFE) grafts. One monofilament suture made of PTFE has a microporous structure that allows it to be channel swaged to a needle that closely approximates its suture diameter. The other suture is a monofilament polypropylene suture that has been extruded to produce a tapered swage end, which was significantly smaller than that of the remainder of the suture in order to be channel swaged to smaller diameter needles. On the basis of comprehensive biomechanical performances, the performance of the new needle suture products with needle/suture diameter ratios approaching 1:1 was superior to needle suture products with 2:1 needle/suture diameter ratios for use in PTFE vascular grafts, regardless of the suture material.

Blood Vessel Prosthesis↗
PubMed1993

Anomalous origin of the sural nerve in a patient with tibial-common peroneal nerve anastomosis.

Recognition of anomalous innervation patterns may be important in dealing with peripheral nerve injuries. We describe a patient who suffered injury to the common peroneal nerve (CPN) at the knee when he laterally dislocated his knee. Intraoperative nerve conduction studies during surgical exploration revealed that nerve fibers from the tibial nerve crossed over to join the CPN immediately distal to a neuroma incontinuity. The sural nerve was also found to arise totally from the CPN.

Adult↗
PubMed1993

Amelioration of secondary ischaemic injury by perfusion with University of Wisconsin (UW) solution in rat skin flaps.

This study was designed to observe the effect of perfusion with University of Wisconsin (UW) preservation solution on skin flap survival following secondary ischaemia caused by venous obstruction in rats. An epigastric flap model was used. Saline-perfused flaps exhibited no significant improvement in survival compared to untreated animals (NS). Skin flaps perfused with UW solution, however, had a significant increase in survival to 40% (8/20) (p < 0.01) when perfused before the onset of primary ischaemia and 30% (p < 0.05) when given before the onset of secondary ischaemia. These results show that UW solution improves skin flap survival, presumably through preservation of the microvasculature.

Adenosine↗
PubMed1993

Vasospastic disorders. Etiology, recognition, and treatment.

This article discusses a group of disorders commonly unappreciated by physicians. The distinction between Raynaud's disease and Raynaud's phenomenon is reviewed. The classification, pathophysiology, and recognition of the vasospastic diseases is reviewed to lay the foundation for understanding the treatment modalities presented.

Biofeedback, Psychology↗