Biomedical subjects

D A Coe

Publications and source records attributed to D A Coe.

18 recordsLinked to original sources

PubMed1999

Cholesterol, but not cigarette smoke, decreases rabbit carotid artery relaxation.

The purpose of this study was to determine the physiologic effects of cigarette smoke exposure and dietary cholesterol on the availability of nitric oxide in carotid vascular rings. New Zealand white rabbits were placed in an airflow chamber for 3 hr/day over an 8-week period and were exposed to smoke from 600 cigarettes/per day added to the chamber inflow by a robotic smoke generator. New Zealand white rabbits, made hypercholesterolemic, and one group fed a normal diet, were similarly placed in the chamber without exposure to cigarette smoke. In those exposed groups, serum cotinine and cholesterol levels were consistently elevated. After the 8-week period, the carotid arteries were harvested. The vessels were cut into 3-mm rings which were suspended from pressure transducers. The rings were contracted with potassium chloride (KCl) to determine vessel integrity. One ring from each carotid was maximally contracted with 1 x 10(-3) molar norepinephrine (NE) while the experimental ring was contracted to 50% of maximum. Relaxation of the rings was achieved by adding incremental doses of acetylcholine. Our results showed that endothelial dysfunction, as measured by acetylcholine-mediated vasorelaxation, occurs in the rabbit carotid artery when exposed to high dietary cholesterol. Cigarette exposure alone in this particular vessel did not result in significant alteration in acetylcholine-mediated vasorelaxation.

Acetylcholine↗

PubMed1999

Behavior problems of children with Down syndrome and life events.

Behavior problems of 44 children with Down syndrome between the ages of 6 and 15 and 44 controls without mental retardation matched for age, sex, and socioeconomic status were compared on the basis of mother and teacher ratings. Ratings from both sources indicated that children with Down syndrome had more behavior problems, in particular attention deficit, noncompliance, thought disorder, and social withdrawal. Life events from the past year were significantly associated with mother but not teacher ratings of Down syndrome behavior problems.

Adaptation, Psychological↗

PubMed1998

Use of texture fading in the treatment of food selectivity.

Children with feeding disorders often display severe food selectivity. For many of these children, consuming highly textured foods may be aversive or potentially dangerous because of frequent gagging. The purpose of this study was to demonstrate the efficacy of texture fading in the treatment of food selectivity displayed by 4 children. Treatment involved the gradual addition of higher textures based on the results of periodic probes. In addition, food acceptance and swallowing were reinforced, while food refusal and food expulsion were placed on extinction. Results showed that all participants successfully advanced to consumption of age-appropriate texture and volume. The results suggest that texture fading with intermittent probes at higher textures may be an effective method for the treatment of food selectivity by texture.

Barium↗

PubMed1997

Pentoxifylline prevents endothelial damage due to ischemia and reperfusion injury.

BACKGROUND: Endothelial injury after ischemia and reperfusion is characterized by an increase in permeability, cellular edema, and loss of acetylcholine-mediated vasorelaxation. Three hours of ischemia followed by 2 hr of reperfusion in the New Zealand white rabbit hindlimb has been shown to result in loss of acetylcholine-induced superficial femoral artery vasorelaxation. The purpose of this study was to evaluate the effect of intraarterial pentoxyfylline (PTX) on this endothelial injury. METHODS: New Zealand white rabbits underwent 3 hr of complete hindlimb ischemia followed by 2 hr of reperfusion. Twenty milliliters of either 100 microM PTX or normal saline was infused over 20 min via the circumflex iliac artery at initiation of reperfusion. Superficial femoral artery rings were then evaluated in vitro for endothelial cell-mediated relaxation. Rings were exposed to standardized incremental doses of acetylcholine after norepinephrine-induced contraction and percentage relaxation was measured. Sections of arteries were also sent for hematoxylin and eosin staining. RESULTS: Similar contraction responses following NE stimulation were observed between control and PTX-treated rings. Control rings relaxed a mean of 14.97 +/- 3.64, 23.17 +/- 5.61, and 31.84 +/- 8.43% in response to acetylcholine doses of 6 x 10(-8), 1 x 10(-7), and 1.5 x 10(-7) M, respectively. In contrast, PTX-treated segments relaxed a mean of 47.52 +/- 8.88, 62.32 +/- 6.83, and 76.73 +/- 4.91% to the same doses of acetylcholine. Differences in relaxation between control and PTX-treated vessels were significantly different at each dose (P < 0.05, Student's t test). Histologic examination of the PTX-treated and control arteries revealed an intact endothelium without morphologic differences between the two groups. CONCLUSION: In this model of rabbit hindlimb ischemia, endothelial cell-mediated vasorelaxation was preserved with the administration of intraarterial PTX during reperfusion compared to controls. The different relaxation responses could not be attributed to altered arterial contractility in response to norepinephrine, or explained by histologic changes in the arterial wall. These studies demonstrate a potential modality for therapeutic intervention to reduce reperfusion injury after acute limb ischemia.

Acetylcholine↗

PubMed1997

Duplex morphologic features of the reconstructed carotid artery: changes occurring more than five years after endarterectomy.

PURPOSE: To determine the late morphologic appearance of the carotid artery after endarterectomy and to relate the morphologic characteristics to the development of recurrent carotid stenosis and subsequent neurologic symptoms. METHODS: Eighty-eight carotid reconstructions (51% included patch angioplasty) in 82 patients were studied 5 or more years after carotid endarterectomy. Duplex color flow imaging was used to determine morphologic characteristics of the carotid endarterectomy site and to document the occurrence, time interval, and progression of recurrent internal carotid artery stenosis. The spatial orientation of recurrent wall thickening, presence of calcium, arterial wall texture, and presence of laminar flow were evaluated. Recurrent stenoses were categorized using standard duplex criteria. RESULTS: The mean duration of follow-up was 99 months (range, 60 to 138 months). Arterial wall calcium was identified in 23% (n = 18), a smooth luminal surface in 57% (n = 46), and laminar flow in 52% (n = 42). Recurrent wall thickening developed in 58 vessels (66%), involving the posterior segment of the vessel in 95%, and anterior, lateral, or medial aspects in 24% (n = 14). Restenosis > 50% diameter reduction occurred in 4% of common carotid arteries (n = 3) and in 15% of internal carotid arteries (n = 13). Ten of the internal carotid artery restenoses occurred after a mean of 76 months (range, 13 to 132 months), and the three remaining patients had asymptomatic occlusions after a mean of 61 months (range, 1 to 96 months). Neurologic events referable to the reconstructed carotid artery occurred in three patients at a mean of 77 months; two were a result of recurrent carotid disease. One symptomatic patient and two asymptomatic patients (3.7%) underwent a second ipsilateral reconstruction for recurrent high-grade stenosis. CONCLUSIONS: The carotid artery remains smooth, with laminar flow and without calcification, in the majority of reconstructions that were observed over a long term. There is a low incidence of subsequent ipsilateral neurologic events or significant recurrent stenosis, both of which usually occur late in the postoperative period. This study documents the long-term durability of carotid endarterectomy in providing risk reduction for stroke.

Aged↗

PubMed1997

Combined exposure to cigarette smoke and hypercholesterolemia decreases vasorelaxation of the aorta.

PURPOSE: The purpose of this study was to determine the physiologic effects of cigarette smoke exposure and dietary cholesterol on the availability of nitric oxide in aortic vascular rings. METHODS: Four groups of New Zealand White rabbits were placed in an air flow chamber for 3 hours per day for 8 weeks. Two of these groups were exposed to smoke from 600 cigarettes per day 5 days a week added to the chamber inflow by a robotic smoke generator. One of these groups was made hypercholesterolemic by being fed a 0.3% cholesterol diet. Two groups of rabbits were similarly placed in the air flow chamber but without smoke exposure, of which one group was also made hypercholesterolemic. After an 8-week period, the rabbits were killed and the infrarenal aortas were excised. The vessels were cut into 3 mm rings and suspended from tension transducers. The rings were contracted with potassium chloride to determine vessel integrity. Then one ring from each aorta was maximally contracted with norepinephrine, and the experimental ring was contracted to 50% of maximum. Relaxation of the rings in response to incremental doses of acetylcholine was measured. RESULTS: No significant differences were seen in contraction to potassium chloride or norepinephrine in any group. A significant decrease in acetylcholine-mediated relaxation was seen only in the smoke-exposed, cholesterol-fed group. CONCLUSIONS: Endothelial damage, as measured by acetylcholine-mediated vasorelaxation, occurs in the infrarenal aorta in rabbits that are exposed to both cigarette smoke and elevated dietary cholesterol. Cigarette smoke exposure alone or hypercholesterolemia alone in this model did not result in significant alteration in acetylcholine-mediated vasorelaxation.

Acetylcholine↗

PubMed1997

Use of extinction and reinforcement to increase food consumption and reduce expulsion.

Extinction and reinforcement contingencies were used to treat 2 children with feeding disorders. Positive reinforcement and avoidance extinction effectively increased food acceptance but also increased food expulsion. Reduced expulsion and increased swallowing were achieved by repeated presentation of expelled food, a second extinction component

Behavior Therapy↗

PubMed1996

Limited thrombogenicity of low temperature, laser-welded vascular anastomoses.

BACKGROUND AND OBJECTIVE: Laser welding of vascular anastomoses has been shown to be feasible, but the clinically relevant advantages of this technique remain to be demonstrated. STUDY DESIGN/MATERIALS AND METHODS: To determine whether laser welding decreases initial anastomotic thrombogenicity, argon laser-welded aortic and venacaval anastomoses were constructed in 15 New Zealand white rabbits. Low temperature welding was done in one-half of welded anastomoses using low power ( < 0.7W) and increased irrigation with saline during welding. Anastomotic surface temperature, bursting strength, procedure time, and surface thrombogenicity (111Indium labeled platelet accumulation) were determined at 24 hours and compared to sutured anastomoses. RESULTS: Aortic and vena caval low temperature laser-welded anastomoses were significantly less thrombogenic than sutured or higher temperature laser-welded anastomoses. In addition, bursting strength of welded anastomoses exceeded physiologic requirements and vessel closure time was less with welding than with suture techniques. CONCLUSION: Low temperature laser welding limits anastomotic thrombogenicity, which may improve early patency of venous and small arterial bypass grafts.

Anastomosis, Surgical↗

PubMed1995

A swallow induction avoidance procedure to establish eating.

Swallow induction has been used to shape swallowing behavior in dysphagic children and to accelerate swallowing in nondysphagic children with profound mental retardation who display primitive swallows. Swallow induction may be considered a type of prompt. This project coupled swallow induction with a modified delayed prompting paradigm to establish eating in a 3.5-year-old girl. Coupling these procedures produced prompt swallowing and established oral consumption. Follow-ups at 1, 2, 6 and 12 months demonstrated maintenance and further improvement of the newly acquired feeding skills. Implications for treatment and further research are discussed.

Avoidance Learning↗

PubMed1994

Rotational atherectomy for treatment of occluded prosthetic grafts.

Potentially, percutaneous rotational atherectomy (RA) can be used to open occluded prosthetic arterial bypass grafts with less morbidity than surgical catheter thrombectomy. However, RA could damage prosthetic grafts or produce significant distal emboli. To investigate this, acutely thrombosed and chronically occluded prosthetic grafts, harvested from dogs, were placed in an ex vivo perfusion system and recanalization was attempted using the TRAC-Wright rotational atherectomy system. Urokinase (UK) was delivered through the RA catheter in one-half of the procedures. Graft surface thrombogenicity and graft mechanical integrity after successful recanalization were determined and debris released during recanalization was collected. Results were compared to those from grafts opened by catheter thrombectomy. One hundred percent (22/22) of acute prosthetic graft occlusions and 39% (16/41) of chronic prosthetic graft occlusions were opened using RA, similar to results achieved using catheter thrombectomy. In addition, surface thrombogenicity after recanalization of acute graft occlusion with RA was lower than that after catheter thrombectomy (P < 0.05) and infusion of UK improved RA success in chronically occluded grafts (52% vs 25%). Debris generated during RA averaged 15-18 micrograms, equivalent to debris generated during catheter thrombectomy, and graft mechanical integrity was unaffected by recanalization using RA. Thus, rotational atherectomy is a minimally invasive means of safe and effective prosthetic graft recanalization that produces a less thrombogenic graft than thrombectomy.

Animals↗

PubMed1994

Contingency contacting. Combining positive reinforcement and escape extinction procedures to treat persistent food refusal.

Chronic food refusal has traditionally been treated with forced feeding and other physical prompting-based procedures when positive reinforcement procedures prove inadequate. Potential problems with such procedures, however, include exacerbation of feeding difficulties and health risks, as well as low parental approval and probability of implementation. Contingency contacting maximizes contact between oral acceptance and positive reinforcement, prevents escape functions of inappropriate behaviors, and requires minimal physical contact between feeder and child. Performances of two children exhibiting chronic food refusal were observed under baseline, positive reinforcement, and contingency contacting conditions. Positive reinforcement increased acceptance only slightly and did not change negative vocalization or interruption for one child. Contingency contacting rapidly increased acceptance and grams of food consumed, and decreased negative vocalization and interruption for both children. Withdrawal to positive reinforcement decreased acceptance for both children and grams consumed for one. Reinstituting contingency contacting rapidly increased acceptance and recovery of grams consumed for one child. Parental approval ratings and treatment and research implications are discussed.

Child, Preschool↗

PubMed1994

Behavioral assessment and treatment of pediatric feeding disorders.

Pediatric feeding disorders are estimated to occur in as many as one in every four infants and children, and when serious can require numerous, costly and sustained interventions. For over a decade research has cumulated evidence on the contributions of Behavior Analysis in understanding and remediating some types of pediatric feeding disorders. The systematic use of this body of evidence in conjunction with other approaches (medical, nutrition, occupational therapy, physical therapy, and so forth) is being carried out on an inpatient treatment unit at the Kennedy Krieger Institute. Key aspects are described here, including direct observation behavior assessment, approaches for increasing and decreasing feeding behavior, skill acquisition, transfer of treatment gains, and parent training. The results based on case studies and overall program evaluation indicate that medically complicated, severe feeding disorders can be treated successfully in a few months with a multidisciplinary approach which incorporates behavioral procedures.

Adolescent↗

PubMed1992

Applied behavior analysis: its impact on the treatment of mentally retarded emotionally disturbed people.

Laboratory research on behavior analysis proved to be useful in establishing principles of learning with many relevant applications for people. Early efforts in the applied behavior analysis area proved to be particularly successful with mentally retarded persons. Self-help skills received much of the earliest attention, but another area that became quite fruitful for study was dual diagnosis--mental health problems of mentally retarded individuals. This paper reviews some of the early works of Skinner and his colleagues and the implications of this work on the rapidly developing subdiscipline of dual diagnosis. Current status and future trends are discussed.

Affective Symptoms↗

PubMed1992

Routine reimplantation of patent inferior mesenteric arteries limits colon infarction after aortic reconstruction.

Ischemic colitis resulting in colonic infarction after aortic reconstruction is a highly lethal complication. Reimplantation of all patent inferior mesenteric arteries should improve this problem but can be justified only if the procedure is effective and safe. To investigate this, 337 aortic reconstructions done between July 1982 and May 1989 were reviewed. Patent inferior mesenteric arteries had been reimplanted when possible during 151 aortic reconstructions done between April 1986 and May 1989. Before this, patent inferior mesenteric arteries were selectively ligated on the basis of intraoperative bowel inspection, colonic mesenteric Doppler signals, and inferior mesenteric arteries stump pressures during 186 aortic procedures. No patient had colonic infarction as a result of ischemia during the period in which patent inferior mesenteric arteries were reimplanted if possible. In contrast, five patients (2.7%; p less than 0.05) had colonic infarction and perforation during the period of selective inferior mesenteric arteries ligation resulting in four deaths. The operative mortality rate was less during the period of inferior mesenteric arteries reimplantation (4.0% vs 14.5%; p less than 0.05), and transfusion requirements were unchanged. Thus routine reimplantation of patent inferior mesenteric arteries limits colonic infarction and operative deaths after aortic reconstruction.

Aged↗

PubMed1991

A comparison and evaluation of three commonly used autism scales.

Reliability and validity of three commonly used autism scales, the Autism Behavior Checklist (Krug, Arick, & Almond, 1980), the Real Life Rating Scale (Freeman, Ritvo, Yokota, & Ritvo, 1986), and the Childhood Autism Rating Scale (Schopler, Reichler, & Renner, 1988), were investigated. Data analyses were based on completed protocols for 24 children or adolescents who met DSM-III-R criteria for pervasive developmental disorders. First, to replicate previous findings, interrater reliability of each of the two direct observational scales was assessed. Second, correlations between pairs of the three scales were calculated. Third, diagnostic classifications based on autism scale cutoff scores were compared to classifications based on DSM-III-R criteria. Fourth, relationships between autism scale scores and adaptive behavior scores were investigated. Results and implications for the use of these scales in the assessment of autistic behaviors are discussed.

Adolescent↗

PubMed1991

A factor analytic study of the Diagnostic Assessment for the Severely Handicapped Scale.

Five hundred six severe and profoundly mentally retarded persons (247 women and 259 men) from Wisconsin and Louisiana were assessed on the Diagnostic Assessment for the Severely Handicapped Scale. A factor analysis yielded six factor scales: tantrums, aggression/conduct, language disorder/verbal aggression, social withdrawal/stereotypy, eating disorders, and sleep disorders. These data demonstrate a nosology of symptoms loading more heavily on vegetative symptoms than what is evident with persons in the mild and moderate ranges of mental retardation and persons who are not mentally retarded. The implications of these findings are discussed.

Activities of Daily Living↗

PubMed1991

A scale for evaluating emotional disorders in severely and profoundly mentally retarded persons. Development of the Diagnostic Assessment for the Severely Handicapped (DASH) scale.

The DASH scale was used to assess 506 profoundly and severely mentally retarded persons (247 females and 259 males). The scale, covering 13 major psychiatric disorders, consists of 83 items derived from DSM-III-R as well as previously published studies of this population. Data were collected on symptom frequency, duration and severity in individual interviews with direct-care staff. Elimination and pervasive developmental disorders were most frequent, self-injurious behaviour disorders most severe. Most symptoms had been evident for at least a year. Inter-rater reliability was generally good.

Adult↗

PubMedDate not supplied

Adolescent depression: relationships of self-report to intellectual and adaptive functioning.

Self-report measures of depression, general psychopathology, and social skills were administered to adolescents ranging from moderate mental retardation to above normal intelligence. Adolescents with mental retardation reported more depression and general psychopathology symptoms. Variance and regression analyses demonstrated distinctions on the basis of mental retardation status for individual measures. Additional analyses identified differences between individuals with above normal intelligence and individuals with mild mental retardation on the basis of depression specifically. Adaptive behavior functioned as a moderator variable, mediating the relationship between depression and intellectual functioning.

Activities of Daily Living↗