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Biomedical subjects

A M Graham

Publications and source records attributed to A M Graham.

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

Antiphospholipid antibodies lead to increased risk in cardiovascular surgery.

BACKGROUND: Antiphospholipid (APL) antibodies are a heterogenous group of antibodies that have been associated with an increase in bleeding complications and a marked increase in thrombotic events, both of which result in significant patient morbidity and mortality. PATIENTS AND METHODS: A retrospective analysis of patients identified to be positive for APL via a university thrombosis registry who had cardiovascular surgery between 1989 and 1994. RESULTS: Seventy-one patients positive for APL antibodies were identified. Of those patients, 19 had cardiovascular surgical procedures (11 women and 8 men, mean age 58.4 years, range 38 to 78). A total of 48 cardiovascular surgical procedures (mean 2.5 procedures/patient) were performed in the 19 patients. These procedures included 13 lower-extremity reconstructions, 11 upper-extremity reconstructions/fistulas, 8 cardiac valve replacements, 5 coronary artery bypass procedures, 5 major amputations, 4 infrarenal aortic reconstructions, and 2 carotid endarterectomies. Sixteen of the 19 patients (84.2%) suffered major postoperative complications. These included 16 thrombosed grafts, 5 strokes, 5 major bleeding events, 2 pulmonary emboli, and 2 myocardial infarctions. Ultimately, 12 of the 19 patients (63.2%) died of complications related to surgery. CONCLUSIONS: This series of patients confirms that patients with circulating APL antibodies are prone to excessive postoperative morbidity and mortality after cardiovascular surgical procedures. The presence of APL antibodies may be a maker of increased risk of complications after cardiovascular surgery.

Adult↗
PubMed1995

Carotid artery duplex scanning in preoperative assessment for coronary artery revascularization: the association between peripheral vascular disease, carotid artery stenosis, and stroke.

PURPOSE: The purpose of this study was to identify high-risk populations for severe carotid artery disease (SCD) and neurologic events (NE) after nonemergency isolated coronary artery bypass graft procedures (CABG). METHODS: Between February 1989 and July 1992, 387 patients underwent preoperative carotid artery duplex scanning as part of a preoperative assessment for nonemergency cardiac procedures. Of these patients, 376 had isolated CABG, and 11 had combined carotid endarterectomy (CEA) and CABG. Patient demographics, risk factors, and preoperative neurologic symptoms were recorded and analyzed. Severe carotid artery disease was defined as a 80% or greater stenosis of either internal carotid artery by carotid artery duplex scanning. Patients were evaluated for neurologic events (cerebrovascular accident, transient ischemic attack, amaurosis fugax, or reversible ischemic neurologic deficits) during the in-hospital postoperative period. RESULTS: The prevalence of SCD was 8.5% (33 patients). The 33 patients with SCD were significantly older (65.6 +/- 6.5 years vs 62.5 +/- 10.4 years, p = 0.02), had previous CEA (27.3% vs 2.0%, p = 0.00001), had preoperative neurologic symptoms (21.2% vs 5.9%, p = 0.002), and had peripheral vascular disease (PVD) (63.6% vs 16.9%, p = 0.00001). The sensitivity of PVD for SCD is 63.6% (n = 21/33) (specificity 83.1%, positive predictive value 25.9%, negative predictive value 96.1%). In patients undergoing CABG alone, those who had postoperative NE were older (69.6 +/- 6.7 years vs 62.5 +/- 10.3 years, p = 0.036) and more likely to have PVD (50% vs 19.7%, p = 0.034), SCD (40% vs 4.9%, p = 0.001) and previous CEA (40% vs 2.7%, p = 0.0002). The incidence of postoperative NE in patients with SCD was 18.2% vs 1.7% in patients without SCD (p = 0.001). The sensitivity of SCD for NE was 40% (n = 4/10) (specificity 95.1%, positive predictive value 18.2%, negative predictive value 98.3%). CONCLUSIONS: PVD may be helpful to identify patients at high risk for severe carotid artery stenosis. Postoperative NE in patients with CABG are associated with increasing age, carotid artery stenosis greater than 80%, previous CEA, and PVD.

Adult↗
PubMed1995

Enhanced revascularisation after angiogenic stimulation in a rabbit model of bilateral limb ischaemia.

OBJECTIVE: We previously demonstrated stimulation of collateral vessel formation in a rabbit model of unilateral limb ischaemia after administration of endothelial cell growth factor (ECGF). To distinguish clearly the effects of ischaemia alone from those of ischaemia combined with angiogenic stimulation in the same animal, a model of bilateral hindlimb ischaemia was used to evaluate further the angiogenic effect of ECGF. DESIGN: Ischaemia was produced in both hindlimbs of 11 rabbits by femoral artery excision. Beginning 10 days later, ECGF (8 mg in 3 ml of saline) was injected in one hindlimb while 3 ml of saline alone was injected in the other every other day for a total of five doses. OUTCOME MEASURES: Calf systolic blood pressure was measured in both limbs on postoperative days, 10, 30, and 50. On day 50, collateral formation was quantitated angiographically, and muscle samples were obtained for quantitation of capillary density and histologic studies. RESULTS: The mean calf systolic blood pressure in the both hindlimbs was similar on day 10 (36.9 +/- 2.3 versus 38.1 +/- 2.9 mmHg) but was significantly higher in the ECGF-treated limb on day 30 (68.9 +/- 3.1 versus 45.0 +/- 2.9 mmHg) and day 50 (83.0 +/- 3.0 versus 57.0 +/- 1.7; p < 0.0001 for both comparisons). On day 50, collateral vessels were significantly more numerous in the ECGF-treated limb (17.2 +/- 1.6 versus 11.0 +/- 0.8; p < 0.0006), as were capillaries (225.9 +/- 11.4 versus 159.6 +/- 12.9 per mm2; p < 0.002). CONCLUSION: Local administration of ECGF enhanced collateral development leading to significantly improved perfusion in the treated as compared with the untreated limb in the same animal. Exogenous administration of an angiogenic mitogen can upregulate the normal collateral response to ischaemia and may be useful in treating severe limb ischaemia.

Angiography↗
PubMed1995

Persistent sciatic artery in association with varicosities and limb length discrepancy: an unrecognized entity?

The persistence of the sciatic artery is an unusual occurrence, with an angiographically demonstrated incidence of 0.06%. There have been 71 cases previously reported. We report an additional case in a 14-year-old boy who presented with a chief complaint of unsightly varices. The involved right limb was notably shorter than the uninvolved left lower extremity. Work-up included physical examination, duplex studies, venography, and angiography. Our patient was found to have a patent deep venous anatomy with valvular incompetency associated with complete persistence of the sciatic artery and a foreshortened right leg. He has done well with conservative treatment. The persistence of a sciatic artery has occasionally been associated with other anomalies including Mullerian and left renal agenesis, A-V fistula formation, hypertrophy or hypotrophy, multiple hemangiomata, neurofibromatosis, or anomalies of leg arteries. The literature describes three previous case reports in which patients presented with gross varicosities and were incidentally found to have persistent sciatic arteries as well as limb length discrepancies. Our patient is a fourth example of this syndrome. This pattern of physical attributes has not been previously described as a distinct entity. The association of venous incompetency, limb discrepancies, and persistence of the sciatic artery may be an incidental finding or may represent a related embryologic event. This relationship merits consideration in a young patient presenting with severe venous varicosities.

Adolescent↗
PubMed1995

Fibromuscular dysplasia of the brachial artery: an endovascular approach.

Fibromuscular dysplasia (FMD) is a nonatherosclerotic segmental disease of unknown etiology primarily affecting muscular arteries of intermediate size. The pathology affects the renal arteries in the majority of cases, followed by the carotid, vertebral, and ilio-femoral arteries. There have been only six reported cases of FMD involving the brachial artery. This case report describes the seventh case and illustrates an endovascular approach to this clinical entity. A 63-year-old female with a history of hypertension presented to vascular surgery clinic with a 4-day history of numbness, pain, and coolness of her left hand. On physical exam, the patient had a normal axillary and brachial pulse, but had only a Doppler signal of the left ulnar artery. There was no Doppler signal of the radial artery. Segmental pressures and PVR waveforms were normal in the upper arm, but there was a significant blunting of the waveform and decrease in pressure at the level of the wrist. An arteriogram revealed significant narrowing and irregularity of the brachial artery with a characteristic "string-of-beads" appearance. There was complete thrombosis of the radial artery and evidence of fresh thrombus in the distal brachial artery. The patient was treated with intra-arterial infusion of urokinase with restoration of the radial pulse and resolution of her symptoms. Subsequently, the patient had a percutaneous transluminal balloon angioplasty of the involved segment of brachial artery, with normal PVR's and segmental pressures upon completion. FMD of the brachial artery and its sequelae are extremely rare, and therefore, there is no consensus on proper management.(ABSTRACT TRUNCATED AT 250 WORDS)

Angioplasty, Balloon↗
PubMed1995

Carotid endarterectomy in a vascular fellowship training program: good results with a consistent technique.

OBJECTIVE: To find out whether carotid endarterectomy performed by senior residents or vascular fellows in a vascular fellowship program with a uniform technical approach can give results equal to or better than the acceptable standard. DESIGN: A case study with follow-up ranging from 121 to 1369 days. SETTING: A university teaching hospital. PATIENTS: Two hundred and one consecutive patients operated on between May 1989 and June 1993. INTERVENTIONS: Isolated carotid endarterectomy. MAIN OUTCOME MEASURES: Neurologic findings, cardiovascular complications and local wound problems after carotid endarterectomy. RESULTS: There were no deaths, one permanent stroke and two significant deficits from which the patients fully recovered. CONCLUSIONS: Carotid endarterectomy can be performed by senior surgical residents and vascular fellows within a vascular fellowship program, with a perioperative stroke and death rate of less than 1% when a uniform approach is used.

Aged↗
PubMed1994

Antibacterial activity, antibiotic retention, and infection resistance of a rifampin-impregnated gelatin-sealed Dacron graft.

PURPOSE: A gelatin-sealed porous Dacron graft impregnated with rifampin was evaluated in a two-part study of its use in preventing prosthetic infection. METHODS: The graft was impregnated by soaking it for 15 minutes in rifampin (1 mg/ml). In part 1 its antibacterial activity and rifampin retention over time were determined. Infrarenal aortic replacement was performed in pigs, and the rifampin concentration of the graft, serum, and perigraft space was assayed up to 96 hours after surgery. In part 2, infection resistance was tested in pigs in which the retroperitoneum was contaminated with Staphylococcus aureus after graft replacement. The postoperative infection rate was compared in three groups: pigs given gelatin-sealed grafts without rifampin (controls), pigs receiving nonimpregnated grafts and intravenous rifampin (15 mg/kg) for 3 days after surgery, and those given the rifampin grafts. RESULTS: Rifampin was present in the grafts for up to 72 hours after surgery and in the perigraft fluid for 24 hours but was never detected in the serum. The grafts had inhibitory activity in vitro against S. aureus and the biofilm phase of Staphylococcus epidermidis for up to 3 days and against Escherichia coli for 2 days. Pigs given intravenous rifampin had a significantly lower infection rate than had control pigs (7/12 vs 13/13; p = 0.02); those receiving the rifampin graft had a lower rate (2/13) than had either the control pigs (p < 0.001) or those given intravenous rifampin (p < 0.04). CONCLUSIONS: This simple method of graft impregnation resulted in antibiotic retention for 3 days and appeared to be superior to intravenous antibiotic administration in preventing perioperative graft infection.

Animals↗
PubMed1994

Simultaneous transplantation of the heart and kidney.

BACKGROUND: Multiple organ transplants have become frequent. Combined heart-and-kidney grafting has been reported recently and we have pursued this in selected cases. AIMS: To devise a protocol for simultaneous heart-and-kidney transplantation, review our clinical experience with the procedure and the causes of cardiac and renal disease in this group. METHODS: Seven patients with advanced cardiac failure (LV ejection fraction < 0.29 units; five with IDCM), and chronic renal failure (serum creatinine > 375 mumol/L) due to a variety of causes, were accepted for combined heart-and-kidney transplantation. Four males, of mean age 33 years, underwent the procedure. Each received his organs from a single cadaveric donor with ABO blood group compatibility and a negative 'current' lymphocytotoxic cross-match, but without regard to HLA-antigen matching. Cardiac ischaemic time averaged 3 hours 40 minutes, the renal first warm time was 0 minutes in all cases, and renal cold and second warm ischaemic times averaged 5 hours 17 minutes and 52 minutes respectively. The heart was grafted first and the kidney second in a procedure which averaged seven hours. Immunosuppression was achieved by induction with antithymocyte globulin, thence steroids, azathioprine and cyclosporin A. RESULTS: No patient required post-operative dialysis. One patient had early urological complications requiring operative correction, but no serious opportunistic infections were observed. Early cardiac rejection on biopsy (ISHT grade 3a) was seen in three patients at four-ten weeks and responded promptly to increased steroids, but severe steroid-resistant rejection of both heart and kidney contemporaneously occurred in one of these three at 19 months and required a course of muromonab-CD3. All four patients developed hypertension. Mean creatinine clearance was 1.23 +/- 0.22 mL/second (74 +/- 13 mL/minute) at last follow-up. All four recipients were alive, well and rehabilitated 5, 20, 28 and 35 months after grafting. Two patients died while waiting for the double procedure and another patient eventually died after being taken off the dual waiting list and receiving a renal transplant only. CONCLUSIONS: In experienced hands, combined heart-and-kidney transplantation is feasible and offers a compelling therapeutic solution in the treatment of advanced cardiac and renal failure. IDCM is a frequent cause of the heart failure in this group.

Adolescent↗
PubMed1993

Evidence for nitric oxide as an inhibitory neurotransmitter in rabbit isolated anococcygeus.

The role of nitric oxide (NO) and ATP as putative inhibitory non-adrenergic, non-cholinergic (NANC) neurotransmitters was investigated in rabbit isolated anococcygeus after block of adrenergic and cholinergic responses, and raising tone with histamine. NANC nerve stimulation produced rapid relaxations which were completely abolished by tetrodotoxin. The magnitude of the NANC inhibitory responses was significantly reduced by the nitric oxide synthase inhibitors NG-nitro-L-arginine (NO-Arg) and NG-nitro-L-arginine methyl ester (L-NAME). This effect could be partially reversed by L-arginine but not by D-arginine. Oxyhaemoglobin inhibited NANC nerve responses and sodium nitroprusside mimicked the effects of NANC nerve stimulation. NO-Arg also reduced the magnitude of the inhibitory junction potentials recorded from the smooth muscle cells during NANC nerve stimulation. Exogenously applied ATP and adenosine each produced concentration dependent relaxations which were unaffected by the NO-synthase inhibitor NO-Arg. Relaxations to adenosine were virtually abolished by the P1 purinoceptor antagonist 8-(p-sulphophenyl)theophylline. Relaxations to ATP were also significantly reduced, indicating that part of the response to exogenous ATP is due to its breakdown to adenosine and subsequent action on P1 purinoceptors. Relaxations of the tissue to ATP and adenosine were unaffected by the P2 purinoceptor antagonist suramin. NANC nerve mediated responses were not significantly changed by either 8-(p-sulphophenyl)theophylline or suramin. These results suggest that NO is involved in inhibitory NANC neurotransmission in the rabbit isolated anococcygeus, but do not support a role for ATP as a NANC neurotransmitter in this tissue.

Amino Acid Oxidoreductases↗
PubMed1993

Angiogenic growth factor and revascularization of the ischemic limb: evaluation in a rabbit model.

We have previously shown that administration of endothelial cell growth factor (ECGF) significantly accelerates revascularization in the ischemic rabbit hindlimb model. Nevertheless, much remains to be learned as to the effectiveness and limitations of this approach. The present study was designed, therefore, to determine whether a dose-response relationship could be demonstrated for this agent, whether it was effective if systemically administered, and finally, whether it affected vascularization in a nonischemic limb. Our established unilateral ischemic rabbit hindlimb model and ECGF administration protocol were used to examine these questions. Three groups of animals were studied to determine a dose-response relationship of ECGF in the ischemic limb. Revascularization was assessed by measurement of calf blood left to right (L/R) pressure ratio before (Day 0) and after ECGF injections (Days 1, 10, and 20) and quantitative vascularization was assessed by angiography at Day 20 when the study was terminated. The results of the dose-response study were [formula: see text] Two other groups of animals were also studied. In Group 4, intramuscular ECGF was injected in the left front limb remote from the ischemic hindlimb and in Group 5 it was injected into the left hindlimb of a normal animal. In neither group was any significant effect on vascularization evident. Thus, our data suggest that the relationship of ECGF and revascularization of the ischemic limb is dose dependent and is demonstrable only when it is administered directly into the limb in the presence of ischemia.

Angiogenesis Inducing Agents↗
PubMed1993

Enhanced revascularization of the ischemic limb by angiogenic therapy.

BACKGROUND: This study tests the efficacy of an angiogenic growth factor, endothelial cell growth factor, in a rabbit model of persistent hindlimb ischemia. METHODS AND RESULTS: Ischemia was induced in the left hindlimb of 22 New Zealand White rabbits by ligation of the distal external iliac artery and complete excision of the common and superficial femoral arteries. Two groups of animals were studied: Group 1 consisted of 11 animals who for 10 days received daily intramuscular injections of 4 mg of endothelial cell growth factor beginning on postoperative day 11, and group 2 consisted of 11 animals who underwent the same surgical ischemic procedure but received only injections of saline daily for the same postoperative period. Perfusion of the ischemic left limb was compared with the normal right limb in each animal on postoperative days 10, 20, 30, and 40 using the calf blood pressure ratio, 99mTc macroaggregate radioisotopic perfusion scans, and serial angiography. Neovascularization in the left thigh at day 40 was quantified from the angiograms. Each technique documented that animals in group 1 had significantly better perfusion than animals in group 2; that is, the calf pressure ratio was higher in group 1 than in group 2 (0.56 versus 0.32 at day 20, 0.64 versus 0.44 at day 30, and 0.70 versus 0.50, P < .0001), and the calf radioisotopic perfusion ratio was also higher in group 1 than in group 2 (0.88 versus 0.74 at day 20, P < .02; 0.93 versus 0.76 at day 30, and 0.96 versus 0.79 at day 40, P < .008). Angiographic studies correlated well with these results demonstrating much earlier distal arterial reconstitution and enhanced neovascularization (23.8 versus 9.0 vessels, P < .007). CONCLUSIONS: The data clearly indicate that an angiogenic growth factor, endothelial cell growth factor, promotes revascularization in this experimental ischemic hindlimb model, raising the possibility that in the future such agents might be of value in humans.

Angiography↗
PubMed1993

Hereditary protein S deficiency in a large New Jersey kindred.

PURPOSE: Protein S is a vitamin K-dependent anticoagulant protein that serves as a cofactor for activated protein C. Deficiency of protein S has been associated with recurrent thrombotic events. To characterize better the risks of thrombosis in protein S deficiency, we studied 62 members in a large kindred. METHOD: All members were evaluated by a thorough clinical history. Plasma samples were assayed for total protein S antigen and protein S activity. Upper and lower extremity venous duplex examinations were performed in the majority of adult members. RESULT: Twenty-six (40%) of the 62 family members were classified as deficient on the basis of either low total protein S antigen levels or low protein S functional activity. Five members deficient in protein S had 16 venous thrombotic events. In all members the onset of thrombotic events occurred after 19 years of age, with a tendency for recurrence. Three lower extremity deep venous thromboses that had been occult previously were first diagnosed on surveillance duplex scanning. Only one member whose protein S level was not deficient had a single episode of superficial thrombophlebitis. CONCLUSION: Our findings in this large kindred confirm an autosomal-dominant inheritance pattern. Thrombotic events occurred after the age of 19 years in affected individuals and tended to be recurrent. The diagnosis of protein S deficiency is based on functional and immunologic plasma assays. In this study venous duplex scanning proved to be a useful diagnostic adjuvant.

Adolescent↗
PubMed1992

Evaluation of muscle flaps in the treatment of infected aortic grafts.

Standard therapy for abdominal aortic graft infection involving resection of the graft and extraanatomic bypass carries significant morbidity and mortality rates. The present study evaluates the feasibility of combining in situ graft replacement with a highly vascular tissue flap as an alternative to this problem. In 52 pigs a segment of a polytetrafluoroethylene graft was interposed in the infrarenal abdominal aorta. Staphylococcus aureus was used to infect the graft. One week later the animals were divided into six treatment groups. Group 1 (control) had debridement of the retroperitoneum only; group 2 had debridement with replacement of the graft; group 3 consisted of animals with the infected graft left in place and the graft wrapped with a rectus abdominis flap; group 4 is similar to group 3 except the seromuscularis of the jejunum was used to wrap the infected graft; in group 5 the graft was changed, and a rectus abdominis island flap was wrapped around the graft; and finally, group 6 was similar to group 5 except that the flap was obtained from the seromuscularis of the jejunum. Two weeks later, graft patency and infection status were assessed at reoperation. The incidence of graft infection was significantly reduced in groups 5 (0 of 10; p less than 0.01) and 6 (1 of 10; p less than 0.02) compared with group 1 (7 of 10), and the incidence of graft thrombosis was also greatly reduced in groups 5 (2 of 10) and 6 (1 of 10) versus group 1 (10 of 10; p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Does the clinical evaluation of the cardiac status predict outcome in patients with abdominal aortic aneurysms?

A cost-effective method to reduce mortality rates after abdominal aortic aneurysm repair centers on selecting and investigating only those patients at risk for cardiac-related death. All 146 patients undergoing asymptomatic abdominal aortic aneurysm repair over a 5-year period (1986 to 1990) were retrospectively placed into one of the three following groups on the basis of a clinical evaluation. Group I: no history of myocardial infarction or angina, no congestive heart failure, and no ischemic changes on electrocardiogram (ECG). Group II: history of myocardial infarction or class I-II angina or ischemic changes on ECG. Group III: presence of congestive heart failure or class III-IV angina. Patients in group I had no further cardiac work-up; patients in group II with angina had left ventricular ejection fraction assessment by multiple gated acquisition (all greater than 37%) and were cleared for operation by a cardiologist; patients in group II without angina had no further cardiac work-up; patients in group III had coronary angiography and then coronary revascularization. The overall mortality rate was 4.8%, with a cardiac mortality rate of 3.4%. The mortality rate in group I (n = 64) was 1.8%, with no cardiac-related deaths; the mortality rate in group II (n = 63) was 9.5% (8% cardiac-related deaths). No deaths occurred in group III (n = 19). The difference between the cardiac mortality rates in groups I and II was significant (p = 0.02) as was the postoperative cardiac morbidity: total myocardial infarctions (p less than 0.001); congestive heart failure (p = 0.02); tachyarrhythmias (p = 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1991

Porcine model for vascular graft studies.

Models for the study of prosthetic vascular graft infection have been studied frequently in the dog and rabbit. We have developed a reproducible swine model to study this problem and its treatment. The cardiovascular system, healing characteristics, and the bloodstream clearance of bacteria in swine more closely resembles those of humans than do other animal models. The low cost and availability of the swine is an additional attractive aspect. One hundred fifty-six farm-bred pigs have undergone infrarenal aortic replacement with a 3-cm segment of 6-mm prosthetic graft over the past two years. Graft infection was produced by (1) direct inoculation of 10(6) Staphylococcus aureus at the time of the surgery or (2) intravenous infusion of bacteria (10(2)-10(6) organisms/mL) immediately after surgery. All animals were sacrificed 1 to 4 weeks later, depending on the study design. Cultures, histology, and electron microscopy were performed on each graft. Anesthetic complications were rare (2.5%). Postoperative complications leading to animal death decreased with increasing experience (11.5%), but included graft thrombosis, bleeding, sepsis, intussusception, and colonic ischemia. Wound infection was the most common cause of morbidity. The swine model is an attractive alternative to that of other animals for the study of prosthetic vascular graft infections. Further details of the operative technique and the comparison to the human and other animal models is discussed.

Animals↗
PubMed1991

Species differences in the clearance of Staphylococcus aureus bacteremia.

Studies on vascular graft infections may be influenced by species differences in bacteria clearance. The present study compares the bloodstream elimination of Staphylococcus aureus (S. aureus) in dogs and pigs. Four mongrel dogs and four Yorkshire pigs received a 20-min infusion of 10(6) S. aureus labeled with indium-131. Through a catheter placed in the infrarenal aorta, blood samples were removed at intervals for 5 h after infusion. The liver, spleen, and lungs were biopsied at 5 h. Blood and tissue samples were then counted in a gamma counter. The calculated phagocytotic index, k, for dogs was 8.6 X 10(-4), while for pigs it was 1.5 X 10(-3), indicating significantly faster bacterial clearance in pigs (p = .009). After 2 1/2 h, significantly fewer counts were present in pigs at most time points (p less than .05). Organ counts indicated higher counts in the dog liver and spleen and in the lungs of pigs (p less than .0001). This study indicates that S. aureus bacteremia is cleared faster by pigs, primarily by the lungs, compared to dogs, in which liver-spleen clearance predominated. These differences should be considered when the results of graft infection studies are compared.

Animals↗
PubMed1990

Replication of the compartment syndrome in a canine model: experimental evaluation of treatment.

The sequence of acute ischemia, reperfusion, and elevated tissue pressure, with subsequent neuromuscular damage, results in the clinical entity known as the compartment syndrome. We have developed a canine hindlimb model that successfully replicates these clinical features. Surgical devascularization of both hindlimbs at the popliteal level isolates perfusion to a single vascular pedicle. Total ischemia is produced in the left limb for 8 h, while the right limb serves as a surgical control. Ischemia is confirmed by measurement of transfascial oxygen tension (TF-PO2) as well as lactate and blood gases in the venous effluent. Pressure in the anterior compartment of the hindlimb is monitored by the slit catheter technique. After reperfusion, muscle damage is assessed by histology, creatine phosphokinase (CPK), and uptake of technetium-99m pyrophosphate (Tc-PyP), expressed as a ratio of the experimental (L) limb to the control (R) limb (L/R ratio). Muscle necrosis was greatest in untreated controls; the L/R ratio was 8.9 +/- 5.0. Significant diminution of muscle necrosis was achieved by fasciotomy prior to reperfusion (2.6 +/- 0.8), mannitol (1.8 +/- 0.6), albumin-conjugated superoxide dismutase (SOD) 2.8 +/- 0.8), native SOD (2.3 +/- 1.0), fasciotomy combined with SOD (1.9 +/- 0.7), and continuous heparin (1.6 +/- 0.4) (p less than .01 vs controls). When fasciotomy was delayed until 2 h after reperfusion, there was no significant decrease in the L/R ratio (5.4 +/- 1.5; p = .15). Early fasciotomy following prolonged severe limb ischemia remains the treatment of choice, although these results suggest an emerging role for nonsurgical therapies as well. A summary of work done with this model as well as a review of other techniques is presented, along with a discussion of the pathophysiology of the compartment syndrome.

Animals↗