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Biomedical subjects

R Bell

Publications and source records attributed to R Bell.

At least 235 records · Page 13Linked to original sources
PubMed1989

Interpretation of urine quantitative 11-nor-delta-9 tetrahydrocannabinol-9-carboxylic acid to determine abstinence from marijuana smoking.

Verification of abstinence from cannabinoid use after initial identification requires documentation of falling quantitative levels of urinary 11-nor-delta-9-tetrahydrocannabinol-9-carboxylic acid (THC-COOH) over an extended time period. We present a case in which normalization of quantitative urinary THC-COOH results to urinary creatinine is required to correctly interpret a series of quantitative levels and confirm abstinence from marijuana smoking.

Creatinine↗
PubMed1988

Effect of hydroxylapatite, tricalcium phosphate, and collagen on the healing of defects in the rat mandible.

The effects of hydroxylapatite and tricalcium phosphate alone or mixed with collagen on the repair of surgically created bony defects in the mandible of 30 rats were evaluated by gross examination and light microscopy. When specimens were examined 4 and 12 weeks after placement of the implants, bone was observed in direct contact with the implants at the periphery; however, in the central portion of the defects, the implants were surrounded by fibrous connective tissue containing macrophages and a few multinucleated giant cells. Neither the hydroxylapatite or the tricalcium phosphate induced bony healing in the defect, and the addition of collagen did not interfere with healing. Because collagen does not alter healing, it might be possible to use it as biocompatible resorbable binder to confine particulate ceramic implants and inhibit their migration.

Animals↗
PubMed1988

Aortobifemoral bypass: the operation of choice for unilateral iliac occlusion?

Aortobifemoral bypass (ABF) is the preferred operation for patients with bilateral aortoiliac occlusive disease, but for those with unilateral occlusion without significant stenosis of the contralateral iliac artery, alternative reconstructions, such as femorofemoral (FF) or iliofemoral (IF) bypass have been advocated. We compared the surgical outcome in 96 such patients after ABF (n = 32), FF (n = 47), or IF (n = 17) bypasses, with biplane arteriography and noninvasive laboratory testing used to assess the contralateral iliac artery and runoff status, in particular, patency of the superficial femoral artery (SFA). Graft patencies were assessed by noninvasive criteria and analyzed by the life-table method. The only death occurred after ABF bypass (3.1%). Primary patency rates at 1, 3, and 5 years with an open SFA were 100%, 89% and 89%, respectively, for ABF; 92%, 92%, and 92% for FF; and 71%, 71%, and 36% for IF. When the SFA was occluded, the primary patency rates at 1, 3, and 5 years were 100%, 100%, and 72%, respectively, for ABF; 72%, 53%, and 35% for FF; and 56%, 56%, and 56% for IF bypasses. There were no later occlusions on the contralateral ("good") side after ABF. Significant progression of atherosclerosis in donor iliac artery was observed in 6% of both FF and IF bypasses. We conclude that ABF is the preferred operation for extensive iliac artery occlusive disease that is hemodynamically significant only on the symptomatic side unless specifically contraindicated by prohibitive risk or abdominal disease. This is particularly true in the face of SFA occlusion.

Actuarial Analysis↗
PubMed1988

Conditioned ethanol preference in rats.

The question of whether ethanol has intrinsically rewarding properties, or whether, as a discriminative stimulus, it can become a conditioned reinforcer as a function of context association was examined. Paired rats consumed more of an ethanol solution than isolated rats over a 15 day 'conditioning' phase and their ingestion rate was increased significantly over the 15 day period. Furthermore, animals exposed to the solution with a conspecific companion during this conditioning phase subsequently showed a marked preference for ethanol over water throughout a 10 day test phase (when all animals were alone) compared to those with prior experience of the solution in isolation. Both groups consumed significantly more ethanol than the controls (with no prior ethanol experience at all) during this test phase. The results suggest that the total context of initial exposure to ethanol mediate its subsequent reinforcing properties, with the prior pleasurable context of being with a conspecific companion generalizing to the ethanol stimulus for the paired group.

Adaptation, Physiological↗
PubMed1988

DH&S: providing a broad array of services to healthcare. Interview by Bill W. Childs.

Deloitte Haskins & Sells (DH&S) is an international professional services firm employing more than 8,700 accountants and consultants in the United States in more than 100 offices. Worldwide, the firm serves clients through a network of 400 offices in 70 countries and employs nearly 26,000 people. DH&S has the reputation of providing high quality services to organizations in all major segments of the economy, including healthcare organizations. Healthcare is one of the firm's primary specialties which has seen rapid growth in the past five years, making it DH&S' fastest growing industry group. And, according to Mike Engelhart, the National Industry director for DH&S' Health Care Services, the firm sincerely believes that the commitments it has made, and continues to make, in providing a broad array of specialized services for the healthcare industry gives those organizations "the competitive edge in healthcare." Recently, U.S. Healthcare Editor/Publisher Bill W. Childs had the opportunity to interview Engelhart and Raeford Bell, who directs DH&S' Health Care Information Systems Practice.

Computer Systems↗
PubMed1988

Reactivation of cell-free models of Physarum plasmodia after myosin reconstitution.

Thin-spread glycerol-extracted Physarum plasmodia were treated with N-ethylmaleimide (NEM) to block myosin-ATPase and contractility. After supplementing the models with purified plasmodial myosin, they could be reactivated and contracted upon addition of ATP. Fluorescently labeled actomyosin fibers ruptured during contraction, resulting in beaded or rod-like contraction centers. Glycerol-extracted plasmodia lose their negative Ca++-dependence during extraction. Reconstitution of NEM-treated models with plasmodial myosin partly restored this Ca++-sensitivity. Thus, either myosin or a factor associated with it seems to be involved in the Ca++-dependent regulation of cytoplasmic actomyosin contraction in Physarum. NEM-blocked models reconstituted with skeletal muscle myosin were not reactivated by ATP. The same plasmodia subsequently incubated with plasmodial myosin were able to contract.

Actomyosin↗
PubMed1987

Acquisition of a brief behavioural experience in the rat is inhibited by the brain-specific monoclonal antibody, F3-87-8.

Intraventricular infusion of the brain-specific monoclonal antibody F3-87-8 is demonstrated to inhibit the acquisition of a passive-avoidance paradigm in a rat model. Antibody was infused prior to, and following, training of a step-down task and recall was assessed after 24 and 48 h. The antibody only inhibited recall when infused prior to training and no effect was seen when administered 6 h after acquisition of the task. No effect was found with absorbed antibody or in sham-operated animals and open field studies showed no alterations in locomotor activity. Results are discussed considering available information on the antigen and current memory/learning theories.

Animals↗