PubMed Health⌕ Search

Biomedical subjects

R G Carlson

Publications and source records attributed to R G Carlson.

At least 19 recordsLinked to original sources
PubMed1992

Does selective vagotomy prevent delayed gastric emptying and altered myoelectric activity following Roux-en-Y gastrojejunostomy?

Delayed gastric emptying occurs frequently following Roux-en-Y gastrojejunostomy. The role of vagal denervation in the etiology of this "Roux-stasis syndrome" is controversial. This study evaluates the effect of selective vagotomy on gastric emptying and motility following Roux-en-Y. Four dogs underwent control gastric emptying studies. The animals then underwent selective vagotomy, antrectomy, and Billroth II gastrojejunostomy, with placement of serosal electrodes. Gastric emptying was assessed with simultaneous myoelectric recordings, and the animals were converted to Roux-en-Y, followed by repeat studies. Gastric emptying was unchanged following selective vagotomy, antrectomy, and Billroth II gastrojejunostomy (T 1/2: 132 +/- 18 min [SEM] versus 118 +/- 14 min control) but was markedly delayed following Roux-en-Y diversion (T 1/2: 286 +/- 44 min; p less than 0.01). All animals went into the fed pattern following Billroth II gastrojejunostomy (migrating myoelectric complex [MMC] interval: 326 +/- 6 min postprandial versus 92 +/- 5 min fasting; p less than 0.01), but no fed pattern was recognized in three of four animals following Roux-en-Y diversion (MMC interval: 68 +/- 12 min postprandial versus 62 +/- 1.5 min fasting; p = NS). In a canine model, selective vagotomy does not prevent delayed gastric emptying or myoelectric alterations following Roux-en-Y.

Anastomosis, Roux-en-Y↗
PubMed1992

Symbolic mediation and commoditization: a critical examination of alcohol use among the Haya of Bukoba, Tanzania.

Low-alcohol-content fermented beverages are thoroughly enmeshed in the social, economic, commensal, and cosmological spheres of life among most peoples of sub-Saharan Africa. This paper describes and analyzes the role of alcoholic beverages as symbolic mediators and commodities among the Haya of northwest Tanzania. Data gathered during field research in 1985-86 are employed to describe the ways in which the Haya portray excessive drinking and the indigenous strategies they use to address frequent drunkenness when it is perceived as a health problem. A central feature of the paper contrasts the role of a cultural schema of four levels of intoxication in processes of symbolic mediation and commoditization, thereby contributing to critical medical anthropological analysis.

Alcohol Drinking↗
PubMed1992

Case management to enhance AIDS risk reduction for injection drug users and crack cocaine users: practical and philosophical considerations.

The AIDS intervention model described herein represents a new "mixed" model of case management, one that combines AIDS risk-reduction education with a modified version of the traditional broker of services model. The case management component of the model is designed to heed and address those immediate needs that may distract a person from attending to the AIDS risk-reduction messages. The educational component of the model can help a person develop interest in the case management services. The result is a model that, theoretically, can have a greater impact than either component alone would have. The advantages of the model are its flexibility, its ability to quickly assess and address clients' concerns, and its short duration that enhances the likelihood that drug users will complete the process.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Erythromycin enhances delayed gastric emptying in dogs after Roux-Y antrectomy.

Delayed gastric emptying occurs in up to 50% of patients after truncal vagotomy and Roux-Y antrectomy and is often resistant to nonsurgical therapy. This study evaluates the effect of erythromycin, metoclopramide, and motilin on delayed gastric emptying in four dogs after Roux-Y antrectomy. Solid food gastric emptying was measured using a radionuclide technique. Study groups were: (1) saline control; (2) erythromycin 1 mg/kg intravenously over 1 hour; (3) erythromycin 3 mg/kg by mouth 45 minutes prior to feeding; (4) metoclopramide 0.6 mg/kg intravenously over 1 hour; and (5) motilin 500 ng/kg intravenously over 1 hour. After Roux-Y antrectomy, saline control dogs had 73% +/- 5% (SEM) gastric retention at 2 hours. After intravenous and oral erythromycin, gastric emptying improved at 2 hours to 27% +/- 6% and 39% +/- 5% (p less than 0.01 compared with control). Erythromycin intravenously and by mouth improved gastric emptying compared with metoclopramide (64% +/- 8%, p less than 0.05). Motilin enhanced gastric emptying to a similar degree as erythromycin, with a 2-hour gastric retention of 37% +/- 4% (NS). Erythromycin improved gastric emptying in dogs with severe Roux-Y gastroparesis and may have clinical application.

Administration, Oral↗
PubMed1991

Erythromycin acts through a cholinergic pathway to improve canine-delayed gastric emptying following vagotomy and Roux-Y antrectomy.

We have demonstrated that erythromycin improves gastric emptying in dogs following truncal vagotomy and Roux-en-Y antrectomy (VRYA). To explore its mechanism of action we studied gastric emptying and myoelectric activity in a canine Roux model and administered atropine simultaneously with erythromycin. Tachyphylaxis was evaluated following short-term administration. Four dogs with delayed gastric emptying following VRYA were studied. Radionuclide solid gastric emptying was measured, with simultaneous myoelectric recordings obtained from the duodenum and Roux limb. Study groups were: (1) saline control (VRYA dogs); (2) erythromycin 1 mg/kg iv over 1 hr; (3) erythromycin 3 mg/kg po tid for 1 week, with repeat studies using erythromycin 1 mg/kg iv over 1 hr; and (4) atropine 0.5 mg/kg iv bolus, followed by a 1-hr infusion of atropine 0.05 mg/kg and erythromycin 1 mg/kg. Control Roux animals had severe gastric retention (73 +/- 5% at 2 hr, compared to 27 +/- 6% following iv erythromycin (P less than 0.01). Clustered spike bursts were observed in the Roux limb following erythromycin. Atropine abolished the gastrokinetic response and suppressed the myoelectric response to erythromycin (81 +/- 3% retention at 2 hr, P less than 0.01 compared to erythromycin alone). The response to erythromycin was unchanged after 1 week of tid administration (40 +/- 14% retention at 2 hr postprandial, P = NS). Erythromycin improves gastric emptying in VRYA dogs via a cholinergic pathway and does not exhibit tachyphylaxis following short-term administration.

Anastomosis, Roux-en-Y↗
PubMed1991

Radiation-associated valvular disease.

The prevalence of radiation-associated cardiac disease is increasing due to prolonged survival following mediastinal irradiation. Side effects of radiation include pericarditis, accelerated coronary artery disease, myocardial fibrosis and valvular injury. We evaluated the cases of three young patients with evidence of significant valvular disease following mediastinal irradiation. One patient underwent the first reported successful aortic and mitral valve replacement for radiation-associated valvular disease (RAVD) as well as concurrent coronary artery revascularization. A review of the literature revealed 35 reported cases of RAVD, with only one successful case of valve replacement that was limited to the aortic valve. Asymptomatic RAVD is diagnosed 11.5 years after mediastinal irradiation compared with 16.5 years for symptomatic patients, emphasizing that long-term follow-up is important for patients receiving mediastinal irradiation. This study defines a continuum of valvular disease following radiation that begins with mild asymptomatic valvular thickening and progresses to severe valvular fibrosis with hemodynamic compromise requiring surgical intervention.

Adolescent↗
PubMed1991

HIV infection and risk behaviors among intravenous drug users in low seroprevalence areas in the Midwest.

We studied behavioral factors that place intravenous drug users at risk for the acquisition and transmission of the human immunodeficiency virus (HIV) in a sample of 855 individuals not in drug treatment, living in central and southwestern Ohio. The HIV seropositivity rate for the sample was 1.5%. Three factors were significantly related to HIV infection: homeless shelter residence (odds ratio [OR] = 7.7, 95% confidence interval (CI) = 3.0-20.0), travel to northeastern HIV hyperendemic areas (OR = 5.2, 95% CI = 1.8-15.4), and recent male homosexual or bisexual behavior (OR = 11.2, 95% CI = 2.9-43.9).

Adult↗
PubMed1990

Oxalate/hydrogen peroxide chemiluminescence reaction. A 19F NMR probe of the reaction mechanism.

The mechanism of the oxalate/hydrogen peroxide chemiluminescence reaction has been examined by magnetic resonance techniques. Investigation of the reactive intermediates involved in chemiluminescence was carried out with bis(2,6-difluorophenyl)oxalate (DFPO) using 19F NMR to probe its reactions with aqueous hydrogen peroxide. Formation and reactions of the intermediate hydroperoxy oxalate ester B along with the formation of the half ester product C and difluorophenol D were monitored by 19F NMR. When the reaction of DFPO and aqueous hydrogen peroxide was carried out in the presence of dansylphenylalanine, a typical fluorescent analyte, the intensity of the resonance due to the intermediate B was diminished in direct proportion to the concentration of the analyte. Comparison of the time/intensity profile of the chemiluminescence emission with that of the 19F NMR transient suggests that the hydroperoxy oxalate ester B is the likely 'reactive' intermediate, capable of participating in a chemically initiated electron exchange luminescence mechanism.

Fluorine↗
PubMed1990

Altered motility and bacterial flora after functional end-to-end anastomosis.

The functional end-to-end technique with a gastrointestinal stapler is commonly used for small-bowel anastomosis, but the effects of this anatomically side-to-side anastomosis on motility are unknown. Fasting small-bowel myoelectric activity and culture results were compared in six animals undergoing handsewn end-to-end and functional end-to-end anastomoses. Serosal electrodes were placed at 10 cm intervals, and the small bowel was divided 25 and 55 cm from the ligament of Treitz. The functional end-to-end and end-to-end techniques were performed in each animal in random order. Fasting myoelectric recordings were obtained at weekly intervals for up to 20 weeks after operation. New electrodes were placed, and additional recordings were obtained from 29 to 39 weeks, 51 to 63 weeks, and 108 to 112 weeks after operation. The recordings were visually inspected for passage of phase 3 of the migrating myoelectric complex (MMC). By 12 to 20 weeks after operation, 91% of MMCs crossed the end-to-end anastomoses versus 22% across the functional end-to-end anastomosis (p less than 0.001). Even 2 years after surgery only 56% of MMCs crossed the functional end-to-end anastomosis. Quantitative bacterial cultures suggested a trend toward bacterial overgrowth in the functional end-to-end anastomosis. These results demonstrate that the functional end-to-end anastomosis alters small-bowel motility to a greater degree than an end-to-end anastomosis and may predispose to bacterial overgrowth.

Anastomosis, Surgical↗
PubMed1989

Pathogenesis of cardiovascular alterations in dogs treated with minoxidil.

Minoxidil and other potent vasodilators cause coronary arterial injury, right atrial hemorrhagic lesions, and subendocardial necrosis in dogs. This paper discusses the pathogenesis of coronary arterial and right atrial lesions associated with minoxidil in the dog. Acute coronary vascular injury characterized by segmental medial hemorrhage and necrosis and perivascular inflammation occurred only during the first few days of treatment, after which tolerance to further acute injury developed. At 30 d or more of treatment, coronary vascular injury was characterized by perivascular fibrosis rarely attended by medial distortion or hyperplasia and subintimal thickening, changes consistent with responses to previous injury. Right atrial hemorrhagic lesions, unlike coronary vascular injury, often became progressively more extensive with continued treatment. At 3 d, atrial hemorrhage and inflammation were confined to the subepicardium of the right atrium, evidently around affected subepicardial branches of the right coronary artery. At 30 d, fibrovascular proliferative right atrial lesions (granulation tissue with evidence of continual hemorrhage) extended from the epicardium to the myocardium, with eventual replacement of the atrial wall by mature connective tissue at 1 yr of treatment. Minoxidil-induced cardiovascular lesions were not prevented by treatment with a beta-blocker (propranolol), or an alpha-blocker (dibenzylene), or by sympathetic neural activity suppression (surgical sympathectomy or constant carotid sinus nerve stimulation), suggesting that the sympathetic response to the pharmacologic activity of minoxidil was not responsible for the induction of the cardiovascular lesions. Minoxidil-related vascular lesions were confined to the most pharmacologically responsive segment of the arterial system, the coronary arteries, suggesting that medial injury may have been associated with tensile changes in the arterial wall.

Adrenergic beta-Antagonists↗
PubMed1987

Fluid retention and burn survival.

The relationship between retained fluid and survival has previously been reported from our burn unit. Two hundred thirty cc/kg lean body mass accurately delineated survivors from nonsurvivors. Our previous study did not account for fluid lost through the burn wound. This study was undertaken to evaluate fluid retention per square meter of body surface area which has been corrected for fluid loss from the burn wound using a formula suggested by Mason et al. Data collected from 95 adult patients with burns greater than or equal to 20% body surface area burn (mean age, 42.4 years; mean burn size, 37.7%), who were admitted to our burn unit between January 1978 and September 1985, were evaluated. All patients included in the study were adequately resuscitated and survived the initial 48 hours. A calculation of the total fluid retained during the first 48 hours postburn and estimation of fluid loss from the burn wound were made. A comparison was made between lean body retained fluid and surface area retained fluid. A positive correlation (r = 0.921; p less than 0.001) was demonstrated between these two methods of assessing fluid retention. Fluid retention determined by either method resulted in a higher correlation with survival than any single predictor (age, per cent body surface area burned) of burn survival. Surface area fluid is as accurate as lean body fluid in predicting survival. Additionally, we determined that for the first 48 hours postburn, 4,425 cc fluid retained per meter square body surface area accurately differentiated survivors from nonsurvivors.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

Fluid retention during the first 48 hours as an indicator of burn survival.

The quantity of fluid retained during the first 48 hours of resuscitation has been suggested as an indicator of burn severity and mortality (13). In this study of 82 adult burned patients with more than 20% total body surface burns we found that the net fluid retention during the first 48 hours of resuscitation was a predictor of burn mortality and additionally 230 cc of retained fluid per kilogram of lean body mass in the initial 48 hours postburn was an excellent means for separating survivors from nonsurvivors. Fluid retention as an indicator of burn severity and mortality was compared to other methods of predicting burned patient mortality. Parameters evaluated included the per cent body surface area burned, per cent full thickness burn, presence or absence of inhalation injuries, sex, age, and ultimate outcome. The Abbreviated Burn Severity Index (ABSI) (14) was determined for each patient using these data. A comparison was made between fluid retention data, per cent body surface area burned, and the calculated Abbreviated Burn Severity Index and patient mortality. The power of each variable to predict mortality was evaluated by stepwise regression analysis. From this analysis net fluid retention during the first 48 hours of resuscitation was as accurate as the Abbreviated Burn Severity Index and was a better predictor of mortality than individual components of that Index.

Adolescent↗
PubMed1984

Dufour's gland triglycerides from Anthophora, emphoropsis (Anthophoridae) and Megachile (Megachilidae) bees (Hymenoptera: Apoidea).

Lipids secreted from the Dufour's glands of the bees Anthophora centriformis, Anthophora californica tarsata, Emphoropsis miserabilis, Megachile (Delomegachile) gemula, M. (Phaenosarus) fortis, M. (Argyropile) parallela, and M. (Melanosarus) xylocopoides primarily consist of short chain (C2-C20) fatty acid triglycerides. Nearly 95% of the triglycerides from Anthophora and Emphoropsis have one palmitoyl-, stearoyl- or arachidoyl moiety, plus two shorter acids (C2-C16). Virtually all triglycerides (98%) from the four Megachile species possess only short-chain fatty acids (C2-C16), often with one like pair of acids.

Animals↗
PubMed1977

Mitral valve replacement: a comparison of two prostheses.

Between November, 1965 and June, 1970, 175 patients underwent mitral valve replacement with the Smeloff-Cutter prosthesis (109 patients) or the toroidal valve (66 patients). The early mortality for patients with a toroidal mitral prosthesis was 18.2 percent (12 patients) and the late mortality 34.8 percent (23 patients). Among patients in whom Smeloff-Cutter mitral valves were inserted, the early mortality was 15.6 percent (17 patients) and the late mortality 23.9 percent (26 patients). During a follow-up period extending at least five years, thromboembolic complications occurred in 25.9 percent (14) of patients with toroidal valves and 7.6 percent (7) of patients with Smeloff-Cutter valves. Reoperation was necessary because of thrombosis of the prosthesis in seven patients with toroidal valves and two patients with Smeloff-Cutter valves. The incidence of endocarditis was the same in both groups. In this study, the Smeloff-Cutter mitral prosthesis proved to be superior to the toroidal valve because of a lower incidence of thromboembolism.

Adolescent↗
PubMed1975

Fetal cardiac interval recorder.

A recorder is described which is capable of continuously measuring intervals between two events of the fetal cardiac cycle, as well as functioning as a routine intrapartum monitor. We have primarily measured the interval between the R wave of the fetal ECG and the second fetal heart sound (R-S2), but the recorder is also capable of measuring R-R, R-A0 (opening of aortic valve), R-Pl (placenta), and R-Sc (scalp) intervals. In the discussion, we endeavor to show that these intervals reflect fetal cardiac performance, which is altered by drugs and acidemia.

Electrocardiography↗