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Biomedical subjects

R C Duncan

Publications and source records attributed to R C Duncan.

At least 73 records · Page 4Linked to original sources
PubMed1990

Effect of neurolinguistic programming training on self-actualization as measured by the Personal Orientation Inventory.

Neurolinguistic programming training is based on principles that should enable the trainee to be more "present"-oriented, inner-directed, flexible, self-aware, and responsive to others, that is, more self-actualized. This study reports within-person changes on self-actualization measures of the Personal Orientation Inventory following a 24-day residential training in neurolinguistic programming. Significant positive mean changes were found for 18 master practitioners on nine of the 12 scales and for 36 practitioners on 10 of the 12 scales. Findings are consistent with the hypothesis that training increases individual self-actualization scores.

Adult↗
PubMed1989

Relationship between the in vitro colony growth of human tumors and cytologic diagnosis.

The cytologic examinations and cloning efficiencies of 47 human tumor specimens (19 ovarian carcinomas, 6 sarcomas, 5 lung carcinomas, and 17 miscellaneous tumors) were compared to evaluate the predictability of clonogenecity by cytologic diagnosis. Cytologic examination preceding clonogenic assay identified the 50% to 60% of all specimens that failed to yield in vitro chemotherapy sensitivity by this assay, with a false-negative rate of 10%. The frequency of cytologically identifiable tumor cells in the plating suspension was independent of the histologic type of tumor (ovarian carcinoma or others) and the nature of the specimen (solid tumor or malignant effusion). Nearly 66% of all specimens were cytologically negative. The in vitro sensitivity can be assessed in approximately 75% of cytologically positive specimens. Cytologic evaluation preceding soft-agar clonogenic assay of human tumors can reduce cost and effort by predicting colony-producing specimens.

Cell Survival↗
PubMed1987

Complement activation and corticosteroid therapy in the development of the adult respiratory distress syndrome.

Fifty-nine patients in septic shock were observed for the development of the adult respiratory distress syndrome (ARDS) prior to and after receiving either 30 mg/kg methylprednisolone sodium succinate, 6 mg/kg dexamethasone sodium phosphate or no steroid. Serum levels of C3, C4 and Factor B allowed classification of 42 patients by activation of complement pathways. Despite a trend toward patients with severe septic shock who activate the alternative pathway being protected from the development of ARDS, complement pathway determination did not allow prediction of the development of ARDS and steroid pretreatment did not influence complement levels or prevent ARDS.

Complement Activation↗
PubMed1987

Single-dose captopril scintigraphy in the diagnosis of renovascular hypertension.

Renal scintigraphy with [99mTc]diethylenetriaminepentaacetic acid (DTPA) and/or sodium-iodine-131-o-iodohippurate (HIP) was performed before and after an oral dose of captopril (50 mg) in 18 patients with renovascular hypertension (RVH) due to renal artery stenosis (RAS) and 18 controls. In every patient with RVH, captopril induced, enhanced or sustained abnormal findings on HIP scintigraphy depending on the degree of RAS. With DTPA scintigraphy, renal function decreased after captopril in ten kidneys with RVH-related RAS and adequate baseline renal function, but this phenomenon was not evident in 11 kidneys with RVH and poor renal function. Captopril did not influence HIP or DTPA studies of kidneys with patent renal arteries (patients after successful renal angioplasty, patients with essential hypertension, contralateral kidneys of patients with unilateral RVH) or ipsilateral kidneys with mild and subcritical (less than 60%) RAS in patients without hypertension and/or normal renal vein renin activity. When HIP and DTPA scintigraphy were compared in the same patients, HIP demonstrated greater sensitivity and specificity than DTPA, particularly in patients with poor renal function. HIP scintigraphy before and after a single dose of captopril may provide a rapid sensitive and minimally invasive test for screening patients with hypertension.

Administration, Oral↗
PubMed1986

Comparison of plasma cholinesterase depression among workers occupationally exposed to organophosphorus pesticides as reported by various studies.

A number of studies have reported on the inhibitory effects of organophosphorus pesticides (OPs) on the enzyme cholinesterase (ChE) among agricultural workers. With the increasing use of OPs, surveys of blood ChE activity on exposed workers may help to identify workers at greatest risk and to provide insight into the use history--e.g., mixing, loading, application, and harvesting--that might lead to a hazardous situation. Although it does appear that measurements of ChE activity are valuable in worker surveillance programs, it is difficult to interpret findings from various studies since they are dependent on the method of assay and the emphasis is usually placed on statistical tests (i.e., p values) that depend on the number of subjects studied. In the present paper a method is presented to compare ChE values reported in several studies utilizing various methods and units of measurement, and to assess the impact of OP exposure as a percentage of subjects with ChE values depressed below normal limits.

Agriculture↗
PubMed1986

A voice-activated, interactive videodisc case study for use in the medical school classroom.

The instructional technology of voice recognition, interactive videodisc, and microcomputer offers new opportunities in medical education. The TIME Project is using this technology to create engaging, believable clinical situations that promote experiential learning, discovery learning, and contextual instruction in the medical school classroom. The TIME Project will conduct a field test of three interactive case studies as part of the introduction to clinical medicine curriculum at five medical schools to determine the educational effectiveness of the prototype design and its acceptance by faculty members and students.

Computer-Assisted Instruction↗
PubMed1985

Grower reported pesticide poisonings among Florida citrus fieldworkers.

In a 1981 survey of 436 Florida citrus growers, 27 pesticide related poisoning incidents were reported that were to have taken place within one year of the interview date. From these reports it is possible to estimate that there are 376 citrus fieldworker related poisonings per year in Florida. This number of estimated poisonings may be developed into an incidence rate of 113 fieldworker poisonings per 10,000 fieldworkers.

Agricultural Workers' Diseases↗
PubMed1985

Pesticide poisonings reported by Florida citrus fieldworkers.

In a 1981 survey of 1811 Florida citrus fieldworkers, 25 pesticide related poisoning incidents involving 29 fieldworkers were reported. Suspected poisonings were categorized into possible and confirmed poisonings, and from these reports it was possible to project an estimated 438 possible poisonings, and 73 confirmed poisonings among all citrus fieldworkers. Confirmed pesticide poisonings were developed into an incidence rate of 34 poisonings per 10,000 permanent and semi-permanent fieldworkers. The number of possible and confirmed poisonings, for all fieldworkers, was then developed into an incidence rate of 160 poisonings per 10,000 fieldworkers.

Adolescent↗
PubMed1985

Monitoring study of urinary metabolites and selected symptomatology among Florida citrus workers.

A cross-sectional monitoring study was made of citrus fieldworkers employed during an entire citrus growing season in Florida. A survey questionnaire was administered to 1811 fieldworkers employed as applicators, mixers, loaders, tractor drivers, general combination workers, and pickers on 436 citrus groves throughout Florida. The study was designed to evaluate exposure to organophosphorus pesticides by analyzing the urine of citrus fieldworkers for dimethyl phosphate (DMP), dimethyl thiophosphate (DMTP), dimethyl dithiophosphate (DMDTP), diethyl phosphate (DEP), diethyl thiophosphate (DEPT), and diethyl dithiophosphate (DEDTP), and to relate the findings to the reported occurrence of selected health symptoms associated with pesticide intoxication. Urine samples were collected for analysis from 332 spray-season workers and 265 harvest-season workers. Measurable DEP residue values were found in 68% of the spray season workers and 43% of the harvesters. However, with the exception of DEP and DETP values in the urine of spray-season workers, metabolite residues were low, often at, or just above, detection limits (which were usually 0.02 ppm but occasionally rose higher, with a few at 0.03 ppm and a very few at 0.04 ppm). Although there was clearly exposure to organophosphates among the citrus fieldworkers, there was no apparent association between the reported health symptoms and the relatively low levels of organophosphate metabolites found in the urine of the workers.

Agricultural Workers' Diseases↗
PubMed1985

Subacute and chronic bone infections: diagnosis using In-111, Ga-67 and Tc-99m MDP bone scintigraphy, and radiography.

The usefulness of indium-111 white blood cell scintigraphy in the diagnosis of subacute or chronic bone infection was examined in 21 orthopedic patients. In-111 WBC imaging was compared with gallium-67 and technetium-99m methylene diphosphonate skeletal scintigraphy and bone radiography, all studies being performed within 1 week. In-111 WBC scintigraphy showed no definite advantage over Ga-67 scintigraphy in the identification of chronic bone infection. The two tests had the same sensitivity (80%) and similar specificity (In-111 WBC 75%, Ga-67 83%; difference not significant). Bone radiography had a sensitivity of 60% and a specificity of 67%. A negative Tc-99m MDP bone scintigram ruled out infection (sensitivity 100%), but because of low specificity (25%), final evaluation required performance of Ga-67 or In-111 WBC scintigraphy.

Adult↗
PubMed1984

The effects of high-dose corticosteroids in patients with septic shock. A prospective, controlled study.

To determine whether corticosteroids are efficacious in severe septic shock, we conducted a prospective study of 59 patients randomly assigned to a methylprednisolone, dexamethasone, or control group. Patients were treated 17.5 +/- 5.4 hours (mean +/- S.E.M.) after the onset of shock, and 55 patients required vasopressor agents. Early in the hospital course, reversal of shock was more likely in patients who received corticosteroids than in those who did not. Four (19 per cent) of 21 methylprednisolone-treated, 7 (32 per cent) of 22 dexamethasone-treated, and none of 16 control patients had reversal of shock 24 hours after drug administration (corticosteroid groups vs. control group, P less than 0.05). Patients treated with corticosteroids within four hours after the onset of shock had a higher incidence of shock reversal (P less than 0.05). At 133 hours after drug administration, 17 (40 per cent) of 43 corticosteroid-treated patients had died, and 11 (69 per cent) of 16 control patients had died (P less than 0.05). However, these differences in reversal of shock and survival disappeared later in the course. Overall, 16 (76 per cent) of 21 patients receiving methylprednisolone, 17 (77 per cent) of 22 patients receiving dexamethasone, and 11 (69 per cent) of 16 controls in the hospital died. We conclude that corticosteroids do not improve the overall survival of patients with severe, late septic shock but may be helpful early in the course and in certain subgroups of patients.

Adolescent↗
PubMed1982

Fluoride tablet supplementation during pregnancy for caries immunity: a study of the offspring produced.

Evidence continues to accumulate that the fetal nutritional need for the mineral fluoride begins early in pregnancy and that tablet supplementation is required during the last two trimesters to supply that need, since fluoridated water alone during pregnancy is not sufficient. This study of 492 children confirms the safety and efficacy of using a sodium fluoride tablet supplement, by means of which the obstetrician can help his pregnant patients produce children with superior teeth that are immune to decay.

Administration, Oral↗
PubMed1982

Reduction of pesticide exposure with protective clothing for applicators and mixers.

Systemic pesticide illness in agricultural workers may result from excessive dermal exposure to pesticides. Workers who apply and mix pesticides (applicators and mixers) are not at special risk. Both acute and chronic exposures can occur from spillage or by environmental contamination of clothing. Two exposure assessment studies were conducted of Central Florida citrus grove workers who applied ethion daily. Measuring the percentage of penetration of ethion through clothing and measuring the daily urinary excretion of diethyl phosphate (DEP) were the techniques used to assess the protection afforded by changing daily to freshly laundered 100% cotton coveralls. Coveralls provided significantly greater protection than did regular clothing and the use of respirators.

Agricultural Workers' Diseases↗
PubMed1981

High performance liquid chromatographic determination of cyanuric acid in human urine and pool water.

A reverse phase high performance liquid chromatographic (HPLC) assay for the quantitative determination of cyanuric acid (CA) in urine and water is described. For purification, samples are passed through a pre-activated reverse phase C18 column. The effluent is dried by lyophilization, and the residue is reconstituted in hexane-washed water and then passed through a prewashed Dowex-1 column. The effluent is again dried by lyophilization, and the dry residue is extracted with hot dioxane. The solution is cooled to ambient temperature and centrifuged. The supernatant liquid is removed, dried under a nitrogen steam, and dissolved in water for final extraction by reverse phase chromatography. This effluent is dried, dissolved in the sodium phosphate monohydrate in methanol (pH 7.0) mobile phase, and injected into a pre-equilibrated chromatographic system. An external standard is used for quantification by peak height comparison. A sample of HPLC column effluent is collected, dried, dissolved in methanol, and used for mass spectrometric confirmation by a solid probe insert procedure. Average combined recovery determined at 1.0, 5.0 and 10.0 micrograms CA/mL is 103 +/- 3% with an average coefficient of variation of 8.6%. Standard deviations for the 3 concentration levels are 0.04, 0.58, and 0.76, respectively, with average precisions of 4.28, 10.92, and 7.61%. The limits of detection are approximately 0.05 micrograms/mL for urine and 0.1 micrograms/mL for swimming pool water. Recorder response to CA is linear over the concentration range 1-10 microgram/mL.

Chromatography, High Pressure Liquid↗