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Biomedical subjects

G J Peterson

Publications and source records attributed to G J Peterson.

At least 19 recordsLinked to original sources
PubMed1999

Rapid detection of the mecA gene in methicillin resistant staphylococci using a colorimetric cycling probe technology.

A Cycling Probe Technology (CPT) assay was developed for the detection of the mecA gene from methicillin resistant staphylococcal cultures. The assay is based on a colorimetric enzyme-immuno-assay (EIA) and uses a mecA probe (DNA-RNA-DNA) labeled with fluorescein at the 5'-terminus and biotin at the 3'-terminus. The reaction occurs at a constant temperature that allows the target DNA to anneal to the probe. RNase H cuts the RNA portion, allowing the cut fragments to dissociate from the target, making it available for further cycling. CPT-EIA uses streptavidin-coated microplate wells to capture uncut probe followed by detection with horseradish-peroxidase conjugated anti-fluorescein antibody. The assay was compared to PCR and shown to accurately detect the presence or absence of the mecA gene in 159 staphylococcal clinical isolates. The CPT-EIA assay takes two hours starting from cultured cells compared with the 24-48 h required for detection of methicillin resistance by conventional susceptibility tests.

Bacterial Proteins↗
PubMed1997

Outcome of abdominal aortic aneurysm repair in patients with previous spinal cord injury in the Department of Veterans' Affairs hospitals.

A retrospective review was carried out to determine the morbidity and mortality of abdominal aortic aneurysm repair in patients with previous spinal cord injury. A population-based study utilizing computer records on all patients in Department of Veterans' Affairs medical centers from 1987-1991 identified 31 patients with spinal cord injury who underwent subsequent infrarenal abdominal aortic aneurysm repair. Additional information was obtained from individual medical records. Some twenty patients (65%) were paraplegics and 11 (35%) were quadriplegics. Aneurysms were most commonly discovered incidentally during work-up of other conditions. All patients had no symptoms referable to their abdominal aortic aneurysm. In total, 29 patients (94%) underwent elective operations. The complication rate (57%) involved mostly pulmonary, cutaneous or urinary tract morbidity. The 30-day mortality rate was 3% for elective abdominal aortic aneurysm repair. Two patients were operated upon as emergencies for rupture, with one operative death. Long-term follow-up revealed a median survival duration of 5.4 years after aneurysm repair. In conclusion, abdominal aortic aneurysm repair in patients with previous spinal cord injury has a low mortality rate. Postoperative complications are often related to spinal cord injury and are potentially preventable; thus, such injury should not preclude surgical intervention for abdominal aortic aneurysm.

Aged↗
PubMed1996

Ischemic colitis complicating abdominal aortic aneurysm surgery in the U.S. veteran.

Ischemic colitis (IC) is an infrequent but serious complication of abdominal aortic surgery. Prior reports have generally described small, selected populations. The aim of this paper is to evaluate characteristics of clinically diagnosed IC in a large non-referral-based population. Using national Veterans Affairs (VA) computer data sets, we identified all patients with the diagnostic codes for both prosthetic replacement of aorta for abdominal aortic aneurysm and subsequent vascular insufficiency of the intestine in the entire VA population from 1987 to 1991. Clinical information on these patients was then requested from the VA Medical Centers where they received care. Patients demographics, clinical data regarding both the aortic surgery and IC, and survival data were extracted from patient charts and computer records. Of 4957 patients who underwent surgery of the abdominal aorta for infrarenal abdominal aortic aneurysm, 58 (1.2%) also had the code for subsequent IC. In 49/58 (74%), sufficient chart-derived and computer-derived data were available for analysis. The mean age was 69 (range 57-95); all were males. Bloody diarrhea was the most frequent symptom and colonoscopy the most common means of diagnosis. Mean time to diagnosis of IC was 5.5 days after aortic surgery (range 1-21 days). Aneurysmal rupture or perioperative hypotension were present in 35/49 patients. Bowel resection with fecal diversion was required in 32/49 (65%). The overall mortality was 54% but it was 89% if bowel resection for bowel infarction was required. Only 2/12 (16%) of those who required fecal diversion and survived underwent eventual stoma closure. Among 7 patients who received second-look laparotomy for IC, additional bowel resection was required in 6. No patient had aortic graft infection diagnosed during the index hospitalization. The overall mean hospitalization duration after the diagnosis of IC was 38 days (range 1-164). IC following aortic aneurysm surgery in this national patient population is infrequently diagnosed. Emergency aneurysm operation and perioperative hypotension are common in patients who develop IC. The majority of patients diagnosed receive surgical intervention. Most patients who undergo fecal diversion retain their stomas.

Aged↗
PubMed1994

Vascular complications from intraaortic balloons: risk analysis.

PURPOSE: The purpose of this study was to assess the incidence of and predictors for vascular complications in patients who required perioperative intraaortic balloon pump (IABP) support. METHODS: Data from 580 patients collected with a retrospective review were statistically analyzed with 25 perioperative parameters, and significant variables were evaluated with multivariate analysis. These data were also statistically compared with data from a 1983 study from our institution. RESULTS: Vascular complications occurred in 72 patients (12.4%). The three aortic perforations were fatal. Ipsilateral leg ischemia occurred in 69 patients. Of these, ischemia was resolved in 82% of patients by IABP removal (21), thrombectomy (21), vascular repair (13), fasciotomy (2), or without intervention (2). Six patients died with the intraaortic balloon in place. Four patients required amputation for ischemia, but all survived. CONCLUSIONS: Vascular complications were not predictive of operative death (p = 0.26). Risk analyses with 25 perioperative parameters revealed that history of peripheral vascular disease, female sex, history of smoking, and postoperative insertion were independent predictors of vascular complications. However, most risk for vascular complications cannot be explained by these factors because of a low R2 value. Compared with the results of our 1983 study, the incidence of IABP-related complications has not changed, but the severity of complications has decreased significantly, and IABP-induced death has decreased significantly.

Adult↗
PubMed1989

True tibial artery aneurysms: case report and literature review.

True tibial artery aneurysms are rare lesions. They may manifest themselves clinically either as a painful leg mass or as evidence of ischemic changes in the foot. Asymptomatic lesions may be found incidentally during arteriography. The need for surgical intervention should be individualized depending on the presentation; the type of surgical intervention is based on coexistent tibial artery anatomy. The present report describes a patient with a true tibial artery aneurysm. Clinical presentation, radiographic findings, and surgical management are described.

Aneurysm↗
PubMed1988

How accurate are ventilation-perfusion scans for pulmonary embolism?

To evaluate the accuracy of ventilation-perfusion scanning in the diagnosis of pulmonary embolism, the pulmonary arteriograms of 55 patients suspected of pulmonary embolism were compared with their ventilation-perfusion scans. The clinical presentation was consistent for the diagnosis of pulmonary emboli in all 55 patients. The scans were divided into the following four categories according to standard guidelines: normal, low, intermediate, and high probability. Three patients had normal scans confirmed by arteriography; 34 patients had high-probability scans, but only 22 (65 percent) were positive at arteriography. The remaining 18 patients had low or intermediate-probability scans (9 patients each), 5 of whom (28 percent) were positive at angiography (sensitivity 82 percent, specificity 57 percent). This study demonstrates the inaccuracy of ventilation-perfusion scanning for the evaluation of pulmonary embolus and may represent the variability of interpretation at individual institutions. Perhaps each institution may need to compare the results of ventilation-perfusion scanning and angiography to optimally select and treat patients.

Adult↗
PubMed1988

Successful repair of a ruptured abdominal aortic aneurysm in a renal transplant recipient.

A 53-year-old renal transplant recipient went into hypovolemic shock due to rupture of his abdominal aortic aneurysm. His successful perioperative and postoperative management are described. Fourteen cases of infrarenal aortic aneurysm repair in hemodynamically stable transplant recipients are reviewed with a discussion of management alternatives.

Aorta, Abdominal↗
PubMed1988

Upper extremity limb salvage accomplished by in situ vein bypass graft.

The need for revascularization procedures in individuals with hand ischemia is uncommon. Previous reports describe the successful utilization of reversed saphenous vein to reconstruct the distal vasculature of the arm. This case report details the use of in situ arm vein to restore perfusion to a threatened hand.

Arteriovenous Shunt, Surgical↗
PubMed1988

The use of deep duplex scanning to predict hemodynamically significant aortoiliac stenoses.

Hemodynamic assessment of aortoiliac occlusive disease is necessary for successful arterial reconstruction of the aorta and legs. Various methods have been proposed and "pull-through" intra-arterial pressures are the "gold standard." Deep Doppler duplex imaging was supplemented with real-time spectral analysis and velocity measurements in 29 cases. Twenty-three of these patients needed arteriography. One hundred sixty-six (166) arterial segments extending from the proximal aorta to the common femoral arteries were independently graded on duplex scans and arteriograms. For severe occlusive disease, duplex scanning is highly accurate (sensitivity 82%, specificity 93%). Velocity measurements were useful in determining the hemodynamic significance of stenoses. Peak systolic velocities in stenoses were measured with a duplex scanner. The pressure gradient calculated with the modified Bernoulli equation (delta P = 4Vmax2) correlated well with the gradients measured during arteriography (r = 0.9, n = 11). These noninvasive velocity measurements and Bernoulli calculations alert arteriographers to obtain special views of suspected areas and suggest the need for "pull-through" pressures and possible balloon angioplasty. In addition, these noninvasive measurements are useful to follow up patients who have mild to moderate aortoiliac disease and after angioplasty.

Aged↗
PubMed1988

Intraoperative duplex scanning after carotid artery reconstruction: a valuable tool.

The operative management of extracranial cerebrovascular occlusive disease requires meticulous surgical technique. Intraoperative duplex imaging (10 MHz B-mode ultrasound combined with 7.5 MHz Doppler spectrum analysis) was used in an attempt to recognize technical problems that might result in serious neurologic injury. Eighty-four carotid arteries were studied in 76 consecutive patients undergoing carotid endarterectomy or reconstruction. Indications for operation included carotid territory transient ischemic attack (n = 36 [43%]), amaurosis fugax (n = 16 [19%]), stroke (n = 11 [13%]), asymptomatic stenosis (n = 11 [13%]), vertebrobasilar transient ischemic attack (n = 7 [8%]), recurrent stenosis (n = 2 [2%]), and trauma (n = 1 [1%]). Arterial anatomy was assessed ultrasonographically and duplex-derived velocity measurements were obtained to assess hemodynamics. Increased velocity measurement was noted to correlate with ultrasound image of stenosis. Technical errors were identified in 17 patients (22%), including six persons with residual internal carotid artery stenoses, three persons with hemodynamically significant stenoses caused by "kinked" internal carotid arteries, eight persons with debris or intimal flaps in their external carotid arteries, and one person with an occluded external carotid artery. The intraoperative duplex scan led to corrective measures during the surgical procedure in eight patients (11%). No new ipsilateral brain injury was noted in the 76 patients postoperatively. Intraoperative duplex scanning accurately identified residual stenosis, intraluminal thrombus, and loose debris. Duplex scanning altered intraoperative decision making in a significant proportion of patients studied.

Carotid Arteries↗
PubMed1986

Acute aortic occlusion from aspergillosis in a healthy patient with survival.

Valvular endocarditis caused by Aspergillus is a lethal disease. Only two survivors, both with infections of prosthetic valves, have been reported in the world literature. This report describes a patient with an Aspergillus valvular endocarditis on a native valve with embolization to the right axillary, left iliac, and left popliteal arteries and the distal aorta. Diagnosis was made from a thromboembolectomy specimen. Treatment consisted of removal of the peripheral arterial emboli, mitral valve replacement, and prolonged intravenous infusion of high-dose amphotericin B. The patient presently has the longest survival period of any patient with an Aspergillus infection on a native heart valve. The importance of early diagnosis and aggressive operative management by the vascular surgeon needed to properly treat these patients is emphasized.

Adult↗
PubMed1984

Considerations in extrathoracic reconstruction for disease of the branches of the aortic arch.

The effectiveness and decreased morbidity and mortality of extrathoracic reconstruction for disease of branches of the aortic arch has been reported by several workers; however, there has been relatively little discussion in the literature in regard to designing the operation to correct the pathophysiologic process of the disease (embolism versus flow reduction). The technique of reconstruction should be selected with regard to a patient's symptoms and arteriographic findings, with embolic phenomena more likely in patients with cerebral hemispheric symptoms and arteriographic stenosis rather than total occlusion. Simple bypass for suspected proximal embolic disease is inadequate.

Aged↗
PubMed1984

Percutaneous recanalization of iliac artery occlusions: an alternative to surgery in the high-risk patient.

Percutaneous transluminal angioplasty was performed successfully in three patients with total occlusions involving the iliac artery. Two patients had occlusion of the external iliac artery and the third patient had occlusion of the common iliac artery. The vessels were still patent at 3-12 months after the procedure. One complication occurred involving a thrombus in the common femoral artery of the diseased leg. The thrombus was surgically removed under local anesthesia. In high-risk patients, percutaneous transluminal angioplasty of total iliac artery occlusions may represent a viable alternative to surgery.

Angioplasty, Balloon↗
PubMed1980

Stump pressure: an unreliable guide for shunting during carotid endarterectomy.

A correlative analysis was made between the neurological status of the awake patient and the internal carotid artery stump pressure in 125 consecutive patients undergoing carotid endarterectomy. There was no mortality in this series. Twenty-four patients lost consciousness immediately after carotid cross-clamping, even though stump pressures were above 50 mm Hg in more than one third of the cases. The majority (80.8%) of the patients tolerated cross-clamping (stump pressures were between 20 and 90 mm Hg). This study demonstrated the variability of cerebral tolerance relative to absolute stump pressure guidelines, such as 25 or 50 mm Hg; reliance on these values to determine the need for intraoperative shunting could lead to stroke at operation. Our experience also showed that assessment of the awake but tranquil patient continues to be the safest and most reliable guide to selective shunting during carotid endarterectomy.

Aged↗
PubMed1978

The antimicrobial activity of urine of paraplegic patients receiving methenamine mandelate.

The antimicrobial activity of urine collected from adult male paraplegics ingesting methenamine mandelate (MM) was evaluated. The in vitro bacterial growth in urine from these patients was inhibited when the free formaldehyde (HCHO) concentration was 10 to 22 microgram per ml. When the HCHO concentration was in the region of 28 microgram per ml or greater, bactericidal effect became apparent. Urine containing 1323 microgram of MM per ml with a pH of 5.9 when freshly voided had sufficient HCHO to be bacteriostatic. Urine containing at least 1740 microgram of MM per ml with a pH of 5.1 or less when freshly voided was bactericidal. The latter concentration of MM in urine was usually achieved when the patient ingested 4 g of MM per day in divided doses and the intake of fluid was not excessive. Under some circumstances an individual receiving MM without an additional acidifying agent may produce urine with a pH low enough to release sufficient HCHO to exert a useful antibacterial effect. However, supplementary acidification with ammonium chloride produced marked lowering of the urinary pH in all patients receiving MM, resulting in bactericidal levels of HCHO.

Adult↗