Search PubMed⌕ Search

Biomedical subjects

R B Rutherford

Publications and source records attributed to R B Rutherford.

At least 37 records · Page 2Linked to original sources
PubMed1999

Options in the surgical management of aorto-iliac occlusive disease: a changing perspective.

The numerous options available for the treatment of aortoiliac occlusive disease have led to controversy over which is best. Not only are the technical aspects of direct aortoiliac reconstruction debated but the role of lower risk but less durable options such as extraanatomic bypass and balloon angioplasty and/or stenting is still unsettled. Rather than yield to the tendency to apply one method preferentially over the others, it is important to realize that each approach has a selective role to play in the overall management of aortoiliac occlusive disease, if applied in appropriate settings. In discussing these applications, the history of these controversies, and the pros and cons of each competitive approach are reviewed, along with the results of experiences with them by the author and others. While it is apparent that outcome data, stratified for location, and degree and extent of the occlusive disease being treated, are still needed for proper comparisons of some competitive techniques, especially balloon angioplasty and stenting, there is sufficient evidence to make certain general recommendations: endarterectomy should be limited to younger patients with soft atheromatous disease of the lower aorta and proximal iliac arteries; a femoral distal anastamosis is preferable to one at the iliac bifurcation; choice of proximal anastamosis should be based on the distribution of aortoiliac occlusive disease; concomitant profundaplasty is effective only if significant profunda narrowing is present (and not simply superficial femoral artery occlusion); the need for concomitant distal bypass can and should be predicted; axillobifemoral bypass should be limited to patients with 'prohibitive' risk or 'hostile' abdominal pathology; and, in view of the low risk and good long term patency of unilateral iliac bypasses, iliac PTA and stenting should not be extended to category III and IV lesions without demonstrating superior long term results for such lesions.

Anastomosis, Surgical↗
PubMed1999

Transplantation of human pulpal and gingival fibroblasts attached to synthetic scaffolds.

Autologous tissue grafting for the restoration of oral tissues is limited by several factors, including the availability of sufficient donor tissue. One solution to this problem may be to develop substitute tissue grafts by attaching disaggregated autologous cells propagated in vitro to scaffolds composed of natural or synthetic polymers. We have earlier demonstrated that human dental pulp and gingival fibroblasts (HPF, HGF) adhere to non-woven polyglycolic acid (PGA) scaffolds, proliferate and produce extracellular matrix in vitro. We now report that such HPF and HGF adhered to PGA scaffolds survive when implanted into subcutaneous sites in immuno-compromised mice. The transplanted cells synthesize and secrete type I collagen, cellular fibronectin and may express genes implicated in transducing bone morphogenetic protein (BMP) signals. Messenger RNA for BMP-2, -4, -7 (OP-1), the BMP type I receptors Act RI, BMPR-1A and 1B, the type II receptor BMPR-II, and type I collagen were detected by reverse transcription-polymerase chain reaction (RT-PCR). These data revealed that three adult human dental pulp and gingival cell populations, each from individual donors, attached to PGA scaffolds and cultured for 24 h in vitro, survive implantation and express genes indicative of a capacity to produce extracellular matrix. The implanted cells may also express genes associated with responsiveness to BMP-mediated tissue inductive signals.

Adult↗
PubMed1998

Human dentin phosphophoryn nucleotide and amino acid sequence.

Dentin sialoprotein (DSP) and phosphophoryns (DPP) are major dentin-specific non-collagenous proteins and are synthesized by odontoblasts. DPP are extremely acidic, rich in aspartic acid and serine, possess a high affinity for calcium and collagen, and are believed to function in dentin mineralization. Whereas DSP and DPP are the products of a single gene in mouse and rat, an analogous human gene has not been described. Using RT-PCR based cloning strategies, we have cloned human DPP cDNA from immature molar root total RNA. The open reading frame of this human DPP cDNA comprises 2364 bp encoding 788 amino acids rich in serine (58%), aspartic acid (26%) and asparagine (9%). These are mostly arranged as (DSS)n (n = 1-16), DS and NSS motifs. The N-terminal sequence (DDP) matches that obtained from human DPP extracted from the roots of immature teeth. The core protein of this human DPP was calculated to have a molecular weight of 76,906 Da and a net charge of -206 with an isoelectric point of 2.65. Of the serine residues, 53% can potentially be phosphorylated by casein kinases I and II. Thus, this newly cloned human cDNA, which encodes a protein with characteristics similar to rat and mouse DPP, is identified as a human DPP.

Amino Acid Sequence↗
PubMed1998

Primary subclavian-axillary vein thrombosis: the relative roles of thrombolysis, percutaneous angioplasty, stents, and surgery.

This article is based on a review of the literature and a survey of vascular surgeons augmented by more recent reports of new therapeutic approaches. Primary subclavian-axillary vein thrombosis (SAVT) occurs mostly (approximately 70%) in the dominant upper extremity of active healthy patients after a period of unusual exercise or arm positioning. In such patients, most experience severe symptoms, and this outlook is not modified by anticoagulant therapy. These patients should be considered for interventional therapy, beginning with catheter-directed thrombolysis. Although it is clear that the initial management of primary SAVT, by catheter-directed thrombolysis, followed by surgical relief of phlebographically demonstrated extrinsic thoracic outlet compression, is well accepted, the preferred method of dealing with residual intrinsic stenoses and occlusions is still controversial. The durability of percutaneous transluminal angioplasty (PTA) or stents still needs to be defined by long-term follow-up, but kinking or compression of the stent has lead to failure when performed without concomitant thoracic outlet (TO) decompression. Thus, in addition to thrombolysis and TO decompression, residual intrinsic stenoses can be treated either by stenting or by surgical reconstruction, the latter preferably through an extended incision that avoids claviculectomy. Surgical reconstructions are favored only for short, proximal occlusions or for residual stenoses, when performed at the same time as thoracic outlet decompression. First rib removal has lost its popularity in the treatment of postthrombotic occlusion of the subclavian-axillary venous segment and should not be used alone in this setting in the absence of objective proof of positional collateral obstruction.

Adult↗
PubMed1997

Recommended standards for reports dealing with lower extremity ischemia: revised version.

Recommended standards for analyzing and reporting on lower extremity ischemia were first published by the Journal of Vascular Surgery in 1986 after approval by the Joint Council of The Society for Vascular Surgery and the North American Chapter of the International Society for Cardiovascular Surgery. Many of these standards have been accepted and are used in the current literature on peripheral arterial occlusive disease. With the passage of time, some oversights, aspects that require clarification, and better modifications have been recognized. This report attempts to correct these shortcomings while reinforcing those recommendations that have proven satisfactory. Explanatory comments are added to facilitate understanding and application. This version is intended to replace the original version.

Acute Disease↗
PubMed1997

How can vascular surgery survive capitated care?

The basic differences between fee-for-service and capitated care are characterized and how they are likely to impact the practicing vascular surgeon are explored. Likely practice scenarios under capitated care are given. If the potential problems associated with using primary care "gate keeper" physicians materialize, secondary "carveouts" by vascular specialists may prove feasible. The alternative, particularly in large patient care consortiums, is to educate gatekeepers with efficient management algorythms in exchange for appropriate referrals. In spite of demonstrable flaws and abuses, capitated, managed care is likely to persist in some form, as an effective way to control spiraling health care costs. Therefore, vascular surgeons need to be prepared to compete under such systems. The major keys to success are efficient use of diagnostic tests, applying conservative, cost conscious indications for intervention, and efficient use of hospital resources (judged by lengths of stay in the intensive care unit and hospital and readmissions under the same diagnosis). In addition to developing better practice profiles, in these and standard mortality and morbity parameters, vascular surgeons need to create or join an efficient practice environment, with a minimum number of efficient personnel and teaching and research costs tightly controlled. To negotiate contracts effectively, vascular surgeons must know their costs, of delivering care on a per capita basis in their environment, adjusted for specific (eg, working or retired) patient populations. Outcomes and cost comparisons and other management research must vie for attention with new technology and basic research.

Capitation Fee↗
PubMed1997

The value of noninvasive testing before and after hemodialysis access in the prevention and management of complications.

The relative value of and selective indications for specific applications of noninvasive testing and imaging in hemodialysis access patients are reviewed. Preoperatively, clinical arterial assessment, including an Allen's test, should be done routinely. This should be augmented by interrogating the ulnar and radial arteries with a Doppler probe, using collateral compression testing, in complex cases, particularly in patients with a history of previous failed fistulas or radial artery cannulations for blood pressure or blood gas monitoring. Vein mapping, using a duplex scan, is valuable in any patient in whom the superficial veins are not easily visible and distend nicely with tourniquet application. Patients who have previously had chronic cannulation of the subclavian or jugular veins, for hemodialysis or other reasons, should have proximal venous outflow obstruction ruled out by a duplex study. Postoperatively, baseline and serial noninvasive monitoring of the arteriovenous fistula (AVF) or shunt cannot be justified as a routine, but study is indicated if a thrill over the venous outflow cannot be detected postoperatively, veins do not become progressively distended after creation of a fistula, or good flows cannot be achieved during hemodialysis. However, in current practice, a dysfunctional, failing, or failed fistula or shunt is usually identified by the observations of the dialysis technician, and the patient is directly referred to the angiography suite, not the vascular diagnostic laboratory. The true identity and extent of such local complications as hematoma, seroma, abscess, cellulitis with phlegmon, or pseudoaneurysm may be difficult to define without the help of ultrasound imaging, which also can direct diagnostic aspiration. Finally, noninvasive testing, consisting of monitoring digital pressures and plethysmography, and their response to compression of the fistula, its venous outflow, the feeding artery proximally and distally, and the companion artery, is a key initial step in evaluating patients with disabling hand symptoms, distinguishing distal steal from focal ischemia, or, by elimination, pointing to venous congestion or secondary carpal tunnel syndrome.

Diagnostic Tests, Routine↗
PubMed1997

Reporting standards for endovascular surgery: should existing standards be modified for newer procedures?

Appropriate standards for reports on endovascular procedures are discussed in terms of whether existing standards suffice or should be revised. SVS/ISCVS and SCVIR reporting standards form the basis for recommendations. The recently revised SVS/ISCVS "recommended standards for reports dealing with lower extremity ischemia" serves appropriately for most outcome comparisons for occlusive disease, that is, where open surgical and endovascular procedures should be assessed by the same standards. Existing endovascular reporting standards are used to augment these where specific considerations pertinent only to endovascular procedures, such as description of lesion, are needed. In some aspects, such as the reporting of complications that are specific to endovascular procedures (eg, contrast-related, medication-related, device-related, and some entry site and deployment-related complications), recent SCVIR recommendations are endorsed. Although some of these apply, additional reporting standards are required for reporting the results of endograft treatment of aneurysmal disease. The former are identified, and the latter are taken from recent recommendations for reports on the endograft repair of infrarenal AAAs and experiences from recent endograft trials. Public disclosures, at professional meetings or press releases, of data lacking the objectivity and uniformity of these reporting standards, because of the time lag before firm data can reach peer-reviewed journals, may mislead and impede progress.

Forecasting↗
PubMed1996

Primary subclavian-axillary vein thrombosis: consensus and commentary.

Fifteen multiple-choice questions concerning options in the management of primary subclavian-axillary vein thrombosis were discussed by a panel of experts and then voted upon by 25 attending vascular surgeons with a special interest in venous disease and considerable experience in subclavian-axillary vein thrombosis. The large majority favored, or agreed upon: (1) early clot removal for active, healthy patients with a need/desire to use the involved limb in work or sport; (2) catheter-directed thrombolysis as initial therapy; (3) further therapy based on follow-up positional venography; (4) surgical relief of demonstrated thoracic outlet compression after a brief period of anticoagulant therapy; (5) conservative therapy if post-lysis venogram showed either (a) no extrinsic compression or (b) a short residual occlusion; and (6) intervention for residual intrinsic lesions with over 50% narrowing. However, there was little unanimity regarding the most appropriate intervention for residual stenoses, with opinion split between surgical and percutaneous transluminal angioplasty. For residual symptomatic occlusion 66% favored jugular vein turndown; only 10% would perform first rib removal.

Angioplasty, Balloon↗
PubMed1996

Expression of genes for bone morphogenetic proteins and receptors in human dental pulp.

Bone morphogenetic proteins (BMP) have been shown to induce reparative dentine formation experimentally but the cells responsible, which respond to BMPs, have not been identified. The BMP signal is probably mediated by interaction of type I and II BMP receptors (R). Here, the RNA of human adult dental pulp and pulp cells in culture was examined by reverse transcription (RT) polymerase chain reaction (PCR) for evidence of mRNA for BMPs. mRNAs for BMP-2, -4, osteogenic protein-1, ActR-1 (activin-like kinase receptor), BMPR-IA, -IB and -II were detected by RT-PCR. The 698-bp PCR fragment for BMPR-IB was used to probe pulp cells for expression of that receptor. Cell expression of BMPR-IB was detected by the hybridization probe. The findings suggest that resident pulp cells may be able to respond to BMPs to initiate tissue formation.

Activin Receptors, Type I↗
PubMed1996

Transfemoral endovascular repair of abdominal aortic aneurysm: results of the North American EVT phase 1 trial. EVT Investigators.

PURPOSE: This report describes the results of a phase 1 trial of endovascular repair of abdominal aortic aneurysm, conducted under FDA protocol in 13 U.S. medical centers from February 1993 to December 1994. METHODS: Forty-six patients 54 to 84 years of age underwent endovascular repair of abdominal aortic aneurysm (diameter, 3.8 to 7.1 cm). Fifteen were treated with the original device (EGS-I), and 31 with a revised over-the-wire system (EGS-II). All patients were periodically observed with contrast-enhanced computed tomographic scan, color-flow duplex scan, and plain abdominal films to evaluate the stability of prosthetic location and to detect any vascular communication with or entry of blood into the aneurysm sac or change in aneurysm size. RESULTS: Thirty-nine implants (85%) were successful; average operating time was 194 minutes. Seven attempts were unsuccessful and were converted to open repair without complication (EGS-I, 5 of 15; EGS-II, 2 of 31). Conversions were caused by iliac stenosis in four patients, subintimal deployment in one, proximal displacement in one, and short distal neck in one. No patients died within 30 days of surgery. Complications included myocardial infarction in one patient, iliofemoral arterial injury in eight, wound infection in seven, required transfusion in eight, transient unexplained fever in nine, and minor emboli with foot petechiae in two. There were no amputations, major emboli, or episodes of mesenteric ischemia. Contrast enhancement outside the graft but within the aneurysm sac was detected initially in 17 grafts (44%), of which nine (53%) resolved spontaneously. Of eight persistent leaks into the aneurysm sac, one was controlled with transluminal balloon angioplasty and one required surgical explanation because of aneurysm enlargement. Six patients continued to have contrast enhancement, but had no evidence of aneurysm enlargement from 6 to 27 months after surgery. Hospital stay averaged 3.8 days (range, 1 to 13 days). Follow-up extends to 27 months, with one non-device related death of respiratory failure at 6 months. Metallic attachment system fracture, a device-related malfunction, was identified in nine implants (23%), which led to one removal; the remaining eight functioned normally with no untoward sequelae. The program was suspended while the defect was corrected. Preparations are complete for the phase 2 portion of the trial. CONCLUSIONS: Endovascular repair of abdominal aortic aneurysm appears to be safe and efficacious. Long-term results and late consequences of attachment system fracture have yet to be determined. The long-term results of perigraft leak into the aneurysm sac are unknown but worrisome in view of adverse outcomes reported by other investigators.

Aged↗
PubMed1996

Pathogenesis and pathophysiology of the post-thrombotic syndrome: clinical implications.

Anticoagulant therapy can successfully prevent pulmonary embolism and rethrombosis in most cases, but cannot affect either early morbidity or the late post-thrombotic sequelae. In carefully selected cases, early clot removal by thrombolysis or thrombectomy may be justified by improved outcome because of the significant role early and late outflow obstruction plays in determining the ultimate severity of post-thrombotic sequelae. Nevertheless, it is recognized that anticoagulant therapy will continue to be used in the majority of patients because of serious intercurrent disease, sedentary lifestyle, limited extent of thrombosis, lack of tissue loss and, unfortunately, delay in referral for treatment.

Anticoagulants↗
PubMed1996

Exposure of the brachiocephalic vessels.

Although the possible combinations of reconstructive procedures used for brachiocephalic arterial lesions are innumerable, all can be performed using four or five basic incisions, singly or in combination, separately or joined by extension. For a number of reasons, not the least of which is that endarterectomy requires more favorable, discrete lesions, bypasses are much more commonly performed than endarterectomy. Direct reconstructions using bypass grafts emanating from the aorta obtain superb patencies but, in the older arteriosclerotic patient with multiple risk factors, cervical bypasses hold the advantage of lower morbidity and mortality. The more common of the cervical or extra-anatomic reconstructions such as carotidsubclavian bypass or transposition themselves have excellent patency.

Aorta, Thoracic↗
PubMed1996

Technology transfer: incentives and disincentives.

Universities and dental schools are increasingly emphasizing the importance of transferring technology based upon faculty research into marketable products. One area of current interest to dentistry involves the utilization of recombinant DNA and protein purification technologies to produce therapeutics based upon the biologic activity of the proteins. This work builds upon the discovery and characterization of several families of protein capable of inducing potent biological responses both in vitro and in vivo. It is motivated by the need to provide patients with additional alternatives for the prevention, diagnosis, arrest or repair of a number of oral conditions or their sequela such as periodontitis, caries, and neoplasia. This article addresses some incentives and disincentives extant within academic institutions encountered during the development of a therapeutic agent for the regeneration of the periodontium. Incentives include professional rewards associated with the development of new therapeutics and disincentives include conflicts between traditional measures of academic achievement and the nature of the work associated with the development of such products. Some ideas for the resolution of disincentives are presented.

DNA, Recombinant↗