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Biomedical subjects

R B Rutherford

Publications and source records attributed to R B Rutherford.

At least 55 records · Page 3Linked to original sources
PubMed1995

Arterial dissections associated with pregnancy.

Two cases of spontaneous arterial dissection occurring in young, multiparous women shortly after delivery of uncomplicated pregnancies are described. Histologic analysis of arterial tissue samples obtained in both cases at points near and remote from the dissection sites shows evidence of significant arterial degeneration and loss of integrity, with changes similar to those observed in pregnant women, women using oral contraceptives, and animals given female sex hormones. The types of arterial lesions associated with pregnancy and their sites of predilection and the etiologic roles of the hemodynamic stresses of pregnancy and hormones are discussed.

Adult↗
PubMed1994

The time-course of the induction of reparative dentine formation in monkeys by recombinant human osteogenic protein-1.

Recombinant human osteogenic protein-1 (hOP-1, BMP-7) induces cartilage and bone formation when implanted in extra- and intraskeletal sites in vivo. rOP-1 also preserves pulp vitality and stimulates reparative dentine formation when placed on partially amputated vital dental pulp tissue. The amount of dentine formed in 6 weeks was earlier found to be proportional to the total amount of rOP-1/carrier placed on the pulp and the capacity of the pulp to respond to rOP-1 appeared to be independent of the amount of coronal pulp removed. This reparative dentine was not completely mineralized after 6 weeks healing. Experiments were now made to determine the capacity of hOP-1 to preserve the vitality of and induce reparative dentine in vital radicular pulps. The extent of tissue mineralization present after 1, 2, 4 and 6 months' healing time in permanent monkey teeth was assessed. Radicular pulp vitality was maintained, reparative dentine formed, and mineralization was nearly 75% complete after 1 month and more than 95% after 4 months. The effects of irrigating the exposed pulps with EDTA, sodium hypochlorite or saline were also compared. Significantly more sodium hypochlorite-treated pulps became non-vital and the root canals of all the non-vital teeth contained bacteria at the time of sacrifice.

Animals↗
PubMed1994

Aortobifemoral bypass, the gold standard: technical considerations.

The controversies that surround the technical aspects of transabdominal reconstruction for aortoiliac occlusive disease, and more specifically ABF, have provided lively debates during the golden era of vascular surgery. It seems almost a pity that, with the resolution of many of these issues, what has become one of the most effective and durable procedures that vascular surgeons have to offer has been beset by PTA and stents on the one side, and a resurgence of extra-anatomic bypass on the other. Hopefully, the coming era of outcome assessment and cost-benefit analysis, coupled with continued advances in perioperative care, will sustain it in its rightful position, as the procedure of choice for bilateral aortoiliac occlusive disease.

Anastomosis, Surgical↗
PubMed1993

Induction of reparative dentine formation in monkeys by recombinant human osteogenic protein-1.

Osteogenic protein-1 (OP-1, BMP-7), a member of the transforming growth factor-beta supergene family, induces cartilage and bone formation when implanted in intra- and extraskeletal sites in vivo. The human OP-1 gene has been cloned and biologically active recombinant OP-1 homodimers (hOP-1) produced. The amount of bone induced by hOP-1 in vivo is related to the amount of protein implanted. Dentine possesses bone morphogenetic protein (BMP) activity. Impure material from allogenic bone with BMP activity induced reparative dentine formation in dogs. The objective of this study was to determine if the amount of reparative dentine stimulated by hOP-1 is related to the amount of protein utilized in direct pulp-capping experiments. Freshly exposed molar and premolar pulps were treated with varying amounts of a complex comprising hOP-1 and a carrier matrix of purified bovine type-1 collagen powder (CM) moistened with sterile saline. Reparative dentine was present in all hOP-1/CM treated teeth (12 of 15) that remained sealed for the 6 weeks' healing. Substantially more new dentine was present in teeth treated with hOP-1/CM than in those treated with Ca(OH)2 paste and the amount of reparative dentine formed was proportional to the amount of hOP-1/CM (P < 0.05). No reparative dentine formed in collagen carrier or untreated teeth. The appearances of the new tissue suggested that much of the mass of the hOP-1/CM was replaced first by a pulp-like connective tissue, which mineralized to form reparative dentine.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Platelet-derived growth factor and dexamethasone combined with a collagen matrix induce regeneration of the periodontium in monkeys.

Platelet-derived growth factor (PDGF) and the glucocorticoid dexamethasone combined with a collagen carrier matrix (CM) induced regeneration of the periodontium in monkeys. Regeneration was stringently defined as: (1) new cementum, (2) new supra-crestal bone extending coronally from the residual alveolar interdental septum and (3) functionally-oriented periodontal ligament fibers attaching new cementum to new bone. A single application of PDGF/dexamethasone/CM or CM was placed in debrided lesions of experimental periodontitis displaying 3-5 mm of attachment loss associated with horizontal and angular bony defects. Regeneration, judged histologically by these criteria and quantified by computer assisted histomorphometry after 4 weeks, was present only in PDGF/dexamethasone/CM treated lesions and not in those treated with CM or debridement alone. PDGF/dexamethasone/CM induced 5-fold more new cementum and ligament, and 7-fold more supra-crestal bone than control treatments. The presence of substantial amounts of regenerated periodontium including increased height of the alveolar bone; fill of vertically resorbed interdental alveolar septa in PDGF/dexamethasone/CM treated lesions suggests that this combination may provide a new therapeutic agent for the regeneration of lesions of periodontitis associated with horizontal as well as angular bony defects.

Alveolar Process↗
PubMed1993

Functional benefits of peripheral vascular bypass surgery for patients with intermittent claudication.

Many patients with peripheral arterial disease (PAD) undergo peripheral bypass surgery to relieve the symptom of intermittent claudication. However, measurement of graft patency alone, assessed by change in ankle blood pressure, may not adequately reflect the improvement in functional status following the operation. Fourteen patients with moderately severe intermittent claudication were evaluated before and after bypass surgery to asses changes in hemodynamics (by resting ankle-brachial indices-ABIs), exercise performance (by a graded treadmill protocol), and community-based walking ability (by a questionnaire that characterizes self-reported walking speed and distance). Six weeks after surgery, resting ABIs improved in surgical patients (from 0.56 +/- 0.09 to 0.93 +/- 0.16, P < 0.05). Peak treadmill walking time improved from 6.2 +/- 5.9 to 11.8 +/- 7.1 min (90%), peak oxygen consumption from 15.5 +/- 6.5 to 19.1 +/- 8.5 mL/kg/min (23%), and pain-free walking time from 1.5 +/- 0.4 to 6.0 5.5 min (290%). Questionnaire scores for walking distance improved by 203% and for walking speed by 130% (all P < 0.05). After twelve weeks, improvements other than pain-free walking time were maintained. Changes in peak treadmill performance or questionnaire scores were not correlated with the initial ABI, changes in ABI six or twelve weeks after surgery, or the type or extent of bypass surgery. The results demonstrate that surgical treatment of PAD, indicated for the relief of intermittent claudication, improves exercise performance and self-reported community-based walking ability. The change in functional status of the patient is an important outcome of surgery that cannot be predicted from routine noninvasive testing alone and should be measured directly.

Aged↗
PubMed1993

Congenital vascular malformations: diagnostic evaluation.

The management of CVMs is indeed difficult and is particularly frustrating because in most cases, complete cure or long-lasting control is not often possible by surgery or embolotherapy. However, the majority of patients with peripheral CVMs can be well-managed by conservative measures with only occasional intervention, and this provides some consolation. Nevertheless, it is important to be able to make a reasonable prognosis and set forth a therapeutic plan to the patient or the patient's parents, when the patient first presents. The approach recommended here allows one to establish the appropriate diagnosis and classify the CVM according to its vascular components. In addition, by assessing its hemodynamic or physiological effects and defining its anatomic extent and involvement of adjacent structures, one is in a position to provide definitive advice at the outset and continue to follow and manage the patient in a logical fashion using angiography sparingly, often only before the ultimately needed therapeutic intervention.

Algorithms↗
PubMed1993

Ruptured mesenteric artery aneurysm in a patient with alpha 1-antitrypsin deficiency: etiologic implications.

Clinical observations suggest that some aneurysms may be manifestations of intrinsic tissue abnormalities or systemic disease. Several investigators have reported reduced elastin content and increased elastase activity in infrarenal aortic aneurysms. Alpha 1-antitrypsin is the primary serum protease inhibitor modulating elastase activity. Elevated elastase activity caused by reduced alpha 1-antitrypsin inhibition, theoretically, could contribute to aneurysm formation. We report a case of ruptured middle colic artery aneurysm in a patient with multiple visceral artery aneurysms and profound alpha 1-antitrypsin deficiency. Reported middle colic artery aneurysms are reviewed, and etiologic implications are discussed.

Aneurysm, Ruptured↗
PubMed1992

Synergistic effects of dexamethasone on platelet-derived growth factor mitogenesis in vitro.

Platelet-derived growth factor (PDGF) and insulin-like growth factor-I (IGF-I) interact to stimulate proliferation of fibroblasts in culture. Glucocorticoids variably effect the response of cultured fibroblasts to polypeptide growth factors. This study determined the effects of dexamethasone on growth-factor stimulation of gingival, periodontal ligament and pulp fibroblast proliferation in vitro. Cultures of quiescent, low-passage, human fibroblasts were treated for varying periods of time with transforming growth factor-beta 2 (TGF-beta 2), PDGF and IGF-I: (1) alone, (2) in combination with each other, (3) singly plus dexamethasone, (4) in combination plus dexamethasone. Combinations of human, recombinant PDGF and IGF-I (10-1000 ng/ml) induced significantly higher rates of cell proliferation than either factor alone. Dexamethasone at doses ranging from 10(-5) to 10(-8) M substantially enhanced cell proliferation induced by these combinations and by PDGF without IGF-I but not IGF-I alone. By 6 days after a single application, 2-3 times as many cells were present in the PDGF and dexamethasone cultures as compared to PDGF without IGF-I. TGF-beta 2 specifically blocked the effects of dexamethasone added to PDGF-stimulated cells. Collagen and non-collagenous protein synthesis was not affected by the addition of PDGF and IGF-I with or without dexamethasone. These data suggest that dexamethasone may substitute for IGF-I in PDGF stimulation of cell proliferation.

Cell Division↗
PubMed1992

Political issues in endovascular surgery.

"Political issues" may determine the relative progress if not the ultimate success and acceptance of endovascular surgery as much as its intrinsic merits. These issues include turf battles, commercialization of newly developing technologies, unethical advertising, and self-serving reporting practices in presenting clinical results. Acceptable indications, methods of evaluating results, standardized reporting practices, appropriate "gold standards" for comparison, and controlled trials (without premature release) are recommended, as well as an emphasis on the future need for proper training and credentialing and quality assurance programs.

Cost-Benefit Analysis↗