Biomedical subjects

G S McGee

Publications and source records attributed to G S McGee.

At least 19 recordsLinked to original sources

PubMed1994

Popliteal artery injury in a lumberjack.

We discuss the case of a patient with knee dislocation and popliteal artery injury. A high index of suspicion for vascular injury must be maintained in cases of blunt knee injury because more than one third of patients with knee dislocation will have an associated popliteal artery injury. Patients with a grossly unstable knee after blunt trauma often have had a knee dislocation; such patients should receive aggressive evaluation for popliteal artery injury. Arteriography should be done for all trauma patients with a grossly unstable knee joint or knee dislocation and palpable pedal pulses. For patients with severe limb ischemia, arteriograms may be done in the operating room to expedite revascularization. Without rapid recognition and revascularization, blunt injury to the popliteal artery results in a rate of limb loss of more than 30%.

Accidents, Occupational↗

PubMed1994

Management of exposed inguinofemoral arterial conduits by skeletal muscular rotational flaps.

Peripheral vascular reconstructions are common operations for the treatment of occlusive atherosclerosis, and the vast majority are uncomplicated. However, despite all precautionary measures, a small percentage of patients will manifest wound infection and graft exposure that may evolve to loss of limb and/or life. Treatment has traditionally consisted of systemic administration of antibiotic medication(s), graft extirpation, and extra-anatomic arterial bypass; yet despite use of these more radical modalities, morbidity and mortality have remained high. An additional meritorious adjunct for the treatment of exposed prosthetic or autogenous saphenous vein arterial bypass grafts is the use of local/regional autogenous skeletal muscular rotational flaps. Reported herein are the results of this technique applied to the inguinofemoral regions of eight patients. Rectus abdominis (1 patient), rectus femoris (4), and sartorius (4) skeletal muscular rotational flaps were employed. Seven of eight (88%) patients convalesced well at mean duration of follow-up measuring 24 months, although one patient subsequently required major amputation due to progression of occlusive atherosclerosis. One of eight (12%) patients succumbed secondary to irreversible sepsis, despite radical amputation. The data suggest that use of local/regional skeletal muscular rotational flaps is a useful adjunct for the treatment of patients with exposed arterial conduits.

Adult↗

PubMed1993

Limb-threatening ischemia complicated by perigenicular infection.

When graft infection or infection of the medial leg or popliteal fossa precludes a standard approach to revascularization of the ischemic leg, the literature suggests amputation may be the most prudent course because of excessive perioperative mortality and morbidity of attempts to reestablish axial flow. The purpose of this study is to define the outcome of revascularization when limb-threatening ischemia is complicated by perigenicular infection. Of 1020 infrainguinal reconstructions performed since 1984, nine (0.9%) presented with limb-threatening ischemia and graft or wound infections involving the popliteal fossa (6) or medial thigh or calf wounds (3) which precluded standard revascularization in the five women and four men. Risk factors for infection included diabetes mellitus (5/9), wound hematoma at initial operation (2/9), and intravenous drug abuse (1/9); Staphylococcus aureus was the predominant organism in all infected wounds and two popliteal fossa infections. The other deep infections grew group D streptococci, Enterococcus, and Salmonella. Extra-anatomic reconstruction was performed from the femoral (7) and iliac vessels (2) extending to the below-knee popliteal (2), the anterior tibial (4) and the peroneal (3) arteries using vein (5), and PTFE (4) in a lateral tunnel which avoiding the plane of the infection. Postoperative complications included MI (1), early graft thrombosis (2), and osteomyelitis of the femur (1); there were no deaths. With a mean follow-up of 19 months (3-57 months), primary graft patency was 66% and secondary patency was 78%, resulting in salvage of 66% of extremities at risk. These data demonstrate the safety and efficacy of extra-anatomic reconstruction for maintaining axial flow when limb-threatening ischemia is complicated by perigenicular infection.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1993

Penetrating thermal vascular injury in a child: a case report.

Penetrating vascular trauma in children is most commonly seen in wartime settings or more recently as a result of attempts at invasive imaging. Treatment of these patients can be more complicated than treatment of trauma in adults and must include maintenance of symmetric limb growth, compensatory growth of the vascular graft and its anastomoses, and the need for very long-term graft patency. This report describes the care of a 5-year-old child who was impaled by a hot metal pipe and sustained a penetrating thermal injury to the distal external iliac artery and vein. Issues such as conduit choice, extraanatomic reconstruction, anastomotic suture technique, and soft tissue coverage are reviewed in the report.

Arteriovenous Shunt, Surgical↗

PubMed1993

Popliteal venous aneurysms.

Popliteal venous aneurysms are rarely reported but represent a potentially life-threatening condition requiring accurate diagnosis and surgical resection. Newer techniques including magnetic resonance imaging, computed tomography, and color flow duplex imaging offer new noninvasive methods to define popliteal fossa venous abnormalities. Excision of the aneurysm with venous reconstruction removes the embolic source and maintains prograde venous flow. A posterior surgical approach to the popliteal fossa is recommended to facilitate exposure. Early control of venous outflow is needed to avoid thromboembolism. This report describes the diagnosis and treatment of popliteal venous aneurysms in three patients with a review of the English-language literature.

Adolescent↗

PubMed1992

Antiphospholipid antibodies and arterial thrombosis. Case reports and a review of the literature.

Antiphospholipid antibodies are a relatively heterogeneous mix of immunoglobulins with binding specificities for negatively charged or neutral phospholipids. Currently, the most commonly detected antiphospholipid antibodies include the anticardiolipin antibody, the lupus anticoagulant, and an antibody implicated in false-positive VDRL testing. Recently, a clinical syndrome of vaso-occlusive disorders associated with antiphospholipid antibodies has been identified and may result from immune-mediated disruption of endothelial function. This clinical syndrome encompasses arterial and venous thrombosis, recurrent fetal loss, neurologic dysfunction (eg, migraine, chorea, and encephalopathy), systemic and pulmonary arterial hypertension, and endocardial disease. Although most commonly associated with systemic lupus erythematosus, the antiphospholipid antibody syndrome also has been identified in patients with vaso-occlusive disease without systemic lupus erythematosus. Recently, identification of antiphospholipid antibodies has been facilitated by the development of a more sensitive assay for anticardiolipin antibody. In this article, case histories of three patients with arterial thrombosis and associated anticardiolipin antibodies, including the first associated case of terminal aortic thrombosis, are reviewed and the subject of the antiphospholipid antibody syndrome is discussed.

Adult↗

PubMed1992

Axillary-popliteal artery bypass provides successful limb salvage after removal of infected aortofemoral grafts.

Axillary-popliteal artery bypasses were placed to revascularize 28 extremities for 17 patients who were undergoing removal of infected aortofemoral grafts. Polytetrafluoroethylene (PTFE [polytef]) material was anastomosed to the above-knee popliteal artery in 22 cases and to the below-knee popliteal artery in six limbs. All but one patient had axillary-popliteal grafts in place before excision of the aortic graft. In 12 groins, vein-patch angioplasty was performed after removal of the infected aortic graft to provide retrograde pelvic perfusion and maintain femoral patency for future reconstruction. Three patients (18%) died of septic-related, multisystem organ failure. With a mean follow-up of 25 months, primary patency was 75% at 1 year and 43% at 2 years. Secondary patency, maintained by thrombectomy (n = 7), revision (n = 3), and conversion to warfarin sodium (Coumadin) therapy (n = 6) was 100% at 2 years, and limb salvage was achieved for all surviving patients.

Anastomosis, Surgical↗

PubMed1992

Long-term evaluation of composite sequential bypass for limb-threatening ischemia.

When sufficient vein for a completely autogenous femorotibial artery bypass is not available, composite sequential grafting by using vein combined with polytetrafluoroethylene material is a surgical option. This study reviews what is currently the largest collection of these grafts and focuses on technical aspects and long-term patency characteristics. During a 7-year period 67 composite sequential bypasses were used to manage rest pain (38), ulcer (18), or gangrene (11) in 62 patients (mean age, 66 years). Fifty-two percent were men, and 51% had diabetes. This method was used as a primary reconstruction in 30, a second bypass in 16, and in 21 it was used after multiple other failed bypasses. Femoral to above-knee popliteal (44) and below-knee popliteal (23) 6 mm polytetrafluoroethylene grafts were placed. Then extensions of greater saphenous (57) or lesser saphenous (10) vein were anastomosed to the anterior tibial (19), posterior tibial (26), or peroneal (22) arteries. Fifty-three percent were maintained on long-term warfarin (Coumadin) anticoagulation, and 33% were maintained on aspirin. No deaths occurred in the perioperative period. Bypass patency was ascertained by a Doppler pressure and waveform analysis, with mean follow-up of patency or to the time of graft failure of 33 months (1 to 91 months). Three-year patient survival was 72%. Cumulative life-table primary patency of 72% (1-year), 64% (2-year), and 48% (3-year) was calculated. Two grafts are functioning 7 years after placement. Limb salvage was 84% at 2 years and 70% at 4 years. At the time of failure, five grafts retained a patent venous bypass segment, which allowed prompt reconstruction of the proximal portion. In a comparison of grafts with early failure and those with long-term patency, the SVS/ISCVS runoff score, vein diameter, tibial artery diameter, and coagulation status were similar. However, patients with the popliteal anastomosis above the knee had 2-year patency of 72% compared with 46% for those with below-knee anastomoses. This technique, when possible, appears preferable to an all prosthetic tibial bypass.

Adult↗

PubMed1992

Elastin content, cross-links, and mRNA in normal and aneurysmal human aorta.

Although elastin depletion is thought to be an etiologic factor in abdominal aortic aneurysm, little is known about its transcription and posttranslational modification in normal and diseased human aorta. Our objectives were to quantify total elastin and elastin cross-links (desmosine/isodesmosine [DID]) and to determine if elastin mRNA was detectable in the disease-prone infrarenal aorta from patients with abdominal aortic aneurysm and a comparative group with no aneurysmal diseases. After preliminary extraction and thermolysin digestion, content of DID and the elastin tetrapeptide, valine-alanine-proline-glycine (VAPG), were determined by high-performance liquid chromatography. Tissue mRNA was studied by Northern blot analysis. Mean values (+/- SE) were compared by Student's t test. The proportion of insoluble elastin was markedly decreased in abdominal aortic aneurysm tissue (1.3% +/- 0.04% vs 12% +/- -2.8%; p less than 0.001). There was no difference in the small percentage of elastin solubilized during extraction in abdominal aortic aneurysm (5.3% +/- 1%) and no aneurysmal disease (6.0% +/- 1.2%; p = 0.71) tissues. The DID concentration of insoluble elastin was not different for abdominal aortic aneurysm and no aneurysmal disease tissue (0.18% +/- 0.07 vs 0.18 +/- 0.05 nm DID/nm VAPG; p = 0.97). On the basis of VAPG content, only 26% +/- 4% of the sodium hydroxide insoluble residue from abdominal aortic aneurysm was elastin; the predominate protein(s) was high in polar amino acids. Elastin mRNA was detectable in all tissues.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed1992

Fibromuscular dysplasia of the brachial artery: a case report and review of the literature.

Fibromuscular dysplasia is a nonatherosclerotic, noninflammatory vascular disease that involves primarily medium-sized and small arteries. Fibromuscular dysplasia is characterized by medical fibrosis with or without smooth muscle cell hyperplasia and may produce luminal impingement with severe turbulence. Secondary aneurysmal deformity with or without thrombosis may also contribute to the obstruction. Fibromuscular dysplasia most commonly involves the renal and carotid arteries, with upper-extremity disease rarely reported. This case report describes a patient with digital embolization from brachial artery fibromuscular dysplasia. Angiography demonstrated significant narrowing and irregularity with a characteristic "string-of-beads" appearance of the right midbrachial artery. The abnormal segment was resected and reconstructed with a reversed saphenous vein graft. Histologic studies revealed disruption of the internal elastic lamina and disorientation of the hyperplastic medial smooth muscle cells characteristic of fibromuscular dysplasia.

Aged↗

PubMed1992

Collagen and elastin gene expression in aortic aneurysms.

BACKGROUND: The decreased elastin concentration found in abdominal aortic aneurysms (AAAs) may result from a differential synthetic response wherein elastin gene expression fails to increase in parallel with type I procollagen (COL I) gene expression. The purpose of this study is to determine tissue mRNA levels for elastin and COL I in AAAs compared with levels in normal, age-matched aorta and to determine the relationship between aging and COL I gene expression. METHODS: Total RNA exacted from normal infrarenal aortic tissue (n = 7) and AAA (n = 10) tissue was subjected to Northern analysis. Mean values for COL I, elastin, and alpha-tubulin mRNA levels were compared by use of the Student t test. Age and COL I mRNA levels were analyzed by regression analysis. RESULTS: COL I mRNA was increased significantly in AAAs (1.18 +/- 0.13) compared with normal aortas (0.14 +/- 0.05). A commensurate increase in elastin mRNA (AAAs, 0.11 +/- 0.02, vs normal aortas, 0.39 +/- 0.2) was absent. There was no correlation between age and COL gene expression. CONCLUSIONS: The decreased elastin concentration relative to collagen in AAAs may be explained, in part, by the changes in message level of elastin and collagen. The enhanced COL I gene expression in AAAs is unrelated to age.

Aging↗

PubMed1991

Aneurysm or occlusive disease--factors determining the clinical course of atherosclerosis of the infrarenal aorta.

Atherosclerosis of the infrarenal aorta results in distinct clinical entities--aortoiliac occlusive disease (AOD) and abdominal aortic aneurysm (AAA). Although loss of collagen has been implicated in AAA, collagen accumulation plays a role in AOD. In vivo collagen-gene expression can be assessed using complementary DNA for collagen types I and III alpha-chains. The purpose of this study is to compare total collagen (type I + III) and collagen types I and III messenger RNA in AAA, AOD and normal aorta. Specimens were collected from the infrarenal aorta during operation for AOD (n = 7), AAA (n = 7), autopsy, or organ procurement (normal; n = 7). Northern transfer analysis of total RNA was used to compare mRNA levels for type I and III collagen. After preliminary extraction, specimens were hydrolyzed for hydroxyproline analysis used to calculate total collagen (type I + III). Relative levels of type I (pro-a1[1]) mRNA were greater in both AOD (0.77 +/- 0.35) and AAA tissue (0.94 +/- 0.24; p = 0.6) than in normal aorta (0.02 +/- 0.03). Type III (pro-a1[III]) mRNA levels were also greater in AOD (2.52 +/- 0.19; p = 0.09) and AAA tissue (3.15 +/- 1.3) than in normals (0.97 +/- 0.47). Total collagen concentration was increased in AOD (45.6% +/- 3.1% dry weight; p less than 0.05) but not AAA tissue (27.8% +/- 4%) when compared to normal aorta (34.7% +/- 2.3%). Collagen type I and III gene expression is greater in older, diseased aorta, yet collagen accumulated only in AOD. This implies a similar synthetic response in both AOD and AAA. Thus, proteolytic degradation in AAA appears to determine collagen content and possibly the clinical course of the atherosclerotic process.

Aged↗

PubMed1990

Distal embolization as a presenting symptom of aortic aneurysms.

The records of 302 patients who underwent abdominal aortic aneurysm (AAA) repair between 1985 and 1990 were reviewed. Two hundred and forty-eight patients (82%) were asymptomatic, while 32 patients (11%) had ruptured aneurysms. During this period, 15 patients (5%) presented with distal embolization as the first manifestation of their AAA. The preoperative embolic event resulted in limb-threatening ischemia in 3 patients, digital ischemia in 11, and calf myonecrosis in 1. CT scan was performed in 14 of 15 patients demonstrating irregular, heterogeneous thrombus within the AAA. Only two of the AAAs were larger than 5 cm. Angiography demonstrated occlusive lesions but was not diagnostic for AAA in seven patients and resulted in three episodes of embolization. AAA was repaired with a tube graft in 4 patients while a bifurcated graft was required in 11 patients for aneurysmal (in 4 patients) and occlusive disease (in 7 patients) of the iliac arteries. All cases employed a transperitoneal approach, systemic heparin, and distal occlusion prior to aortic clamping. Complications included three major (below-knee) and five minor amputations, developing or worsening renal failure in five patients (33%), and death in two (13%). In comparison, mortality was 5% for elective repair and 66% for rupture during this same period. CT scan was safer and more informative than angiography. The morbidity of patients with AAA presenting with emboli is comparable with rupture. The risk of embolization does not correlate with size and indicates the potentially dangerous nature of small AAAs.

Aged↗

PubMed1990

Duplex assessment of the renal transplant.

Duplex scanning is an inexpensive, noninvasive method of following renal transplant function. It can accurately define degrees of renal artery stenosis, and it can identify perirenal and perivascular fluid collections. Duplex scanning can provide less-specific information regarding changes in intrarenal vascular impedance that can assist in the diagnosis of acute rejection. It is an important initial method for following patients after renal transplantation.

Cyclosporins↗

PubMed1989

Long-term assessment of a damp-stored, albumin-coated, knitted vascular graft.

In a previous study the authors reported greater endothelialization and thrombus-free surface area in albumin-coated grafts compared with collagen-coated grafts after 1 month's aortic interposition. Another study was undertaken to determine whether these differences persisted after a 6-month implantation period. A 6 cm segment of either an albumin-coated [n = 6] or a collagen-coated [n = 4] graft was implanted into a canine descending thoracic aorta for 6 months. Light micrographs from multiple sections of each explanted graft were scored from 1 to 4, least to most, for tissue ingrowth, perigraft inflammation, and capsular thickness. Using computer planimetry, luminal thrombus free surface area and endothelial coverage were calculated from gross and electron photomicrographs, respectively. The results were averaged and expressed as mean +/- standard error (SEM). After 6 months, no significant differences were noted between the albumin-coated grafts and the collagen-coated grafts, both of which were durable and served equally well as scaffolds for vascular remodeling and tissue incorporation. The authors conclude that the safety, ease of handling, low porosity, low thrombogenicity, and durability of the albuminated grafts warrant their clinical trial.

Albumins↗

PubMed1989

Gastrointestinal tuberculosis: resurgence of an old pathogen.

Thirteen patients with gastrointestinal tuberculosis (GITB) were treated at our hospitals from 1977-1987. Ten of these patients were seen during the last four years. Three patients required operative intervention for management of complications of their disease. This review discusses the presentation, diagnosis, and operative management of GITB. The authors feel that the increasing prevalence of GITB noted in their institution is primarily the result of the growing prevalence of mycobacterium tuberculosis pneumonia across the nation. With the recent influx of patients from areas of endemic tuberculosis and the increasing number of immunosuppressed patients, a surge in the number of patients presenting with GITB is likely to occur in the United States. Surgeons must be conversant with the diverse clinical features and operative management of this disease.

Cecal Diseases↗

PubMed1988

Recombinant basic fibroblast growth factor accelerates wound healing.

Basic fibroblast growth factor (bFGF) stimulates extracellular matrix metabolism, growth, and movement of mesodermally derived cells. We have previously shown that collagen content in polyvinyl alcohol sponges increased after bFGF treatment. We hypothesized that bFGF-treated incisional wounds would heal more rapidly. After intraperitoneal pentobarbital anesthesia, male, 200- to 250-g, Sprague-Dawley rats (n = 27) each underwent two sets of paired, transverse, dorsal incisions closed with steel sutures. On Day 3 postwounding, 0.4 ml of bFGF (recombinant, 400 ng. Synergen) or normal saline was injected into one of each paired incisions. Animals were killed with ether on postwounding Days 5, 6, and 7 and their dorsal pelts were excised. Fresh or formalin-fixed wound strips were subjected to tensile strength measurements using a tensiometer. Breaking energy was calculated. Wound collagen content (hydroxyproline) was measured in wound-edge samples following hydrolysis using high-performance liquid chromatography. There was an overall significant increase in fresh wound tensile strength (13.7 +/- 1.06 vs 19.1 +/- 1.99 g/mm, P less than 0.01) and wound breaking energy (476 +/- 47 vs 747 +/- 76 mm2, P less than 0.001) in bFGF-treated incisions. There was an increase in wound collagen content which was not statistically significant and there was no difference in fixed incisional tensile strength. Histologic examination showed better organization and maturation in bFGF wounds. Recombinant bFGF accelerates normal rat wound healing. This may be due to earlier accumulation of collagen and fibroblasts and/or to greater collagen crosslinking in bFGF-treated wounds.

Animals↗

PubMed1988

Growth factors bFGF and TGB beta accelerate the rate of wound repair in normal and in diabetic rats.

The effects of basic fibroblast growth factor (bFGF) and transforming growth factor beta (TGF beta) on the rate of wound repair in both normal and streptozotocin-induced diabetic rats were investigated using two model systems of wound repair, namely incisional wounding and subcutaneous implantation of polyvinyl alcohol (PVA) sponges. Both models showed the expected wound-healing defects of the diabetic rats. Granulation tissue collected from the implanted PVA sponges showed that the diabetic rats had reduced amounts of collagen, DNA and protein present at the wound site at two time points tested (7 and 9 days post-implantation). Fresh tensile strength of the incisional wounds, a measure of the collagen organization in a wound, was reduced to 53% of normal in diabetic rats on day 7 post-wounding, and was only 29% of normal by day 21. Formalin-fixed tensile strength, a measure of collagen content of the wound, was 41% of normal on day 7, and 78% of normal by day 21, giving evidence that while the collagen concentration of the diabetic wounds approached that of normal wounds, it did not undergo the normal maturation process. A single injection of 2 micrograms of TGF beta directly into the incision three days after wounding resulted in little difference in the fresh and fixed tensile strength of diabetic wounds when tested at 7, 14 and 21 days post-wounding. Normal rats, however, responded well, resulting in a greater than 30% increase in both fresh and fixed tensile strength.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗