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Biomedical subjects

D E Roberts

Publications and source records attributed to D E Roberts.

At least 55 records · Page 3Linked to original sources
PubMed1991

The influence of a calorie supplement on the consumption of the meal, ready-to-eat in a cold environment.

There is a dichotomy between calories issued to soldiers in their daily field rations and the amounts actually consumed. Soldiers frequently consume insufficient calories to maintain body weight. A supplemental pack (740 kcal) was developed, to increase field calorie consumption, and tested with the old and new versions of the Meal, Ready-to-Eat on a 10-day field study in Alaska. Initial and final measurements included body weights, heights, blood, and urine parameters. Daily measurements included the collection of urine samples and completion of a dietary intake log. Energy intakes of the supplemented groups were 4%-11% higher (p less than 0.05) although the calorie intakes were still below the recommended 4,500 kcal/day for cold weather operations. Mean body weight loss ranged from 3.0 lb (1.7%) to 4.8 lb (2.8%). Two groups of the four groups became hypohydrated by day 3, due to low water intake, and only improved after direct intervention to increase drinking. Water and food intakes were strongly correlated (p less than 0.05). Results confirm the success of the supplemental pack as a means of increasing food intake and underscore the importance of water discipline in a cold environment.

Alaska↗
PubMed1989

Pharmacokinetics of recombinant human erythropoietin in patients on continuous ambulatory peritoneal dialysis.

To determine the optimum regimen for giving recombinant human erythropoietin (EPO) to patients on continuous ambulatory peritoneal dialysis (CAPD), the pharmacokinetics of single-dose EPO administered intravenously (120 U/kg), intraperitoneally (50,000 U), and subcutaneously (120 U/kg) was investigated. After intravenous administration serum EPO levels decayed exponentially from a peak of 3959 mU/ml, with a half-life of 8.2 h. 2.3% of the total intravenous dose was lost in the dialysate during the first 24 h. Peak serum EPO levels of 375 mU/ml at 12 h and 176 mU/ml at 18 h were attained following intraperitoneal and subcutaneous administration, respectively. The bioavailability of subcutaneous EPO (21.5%) was seven times greater than that of intraperitoneal EPO (2.9%). These results suggest that subcutaneous EPO represents the most satisfactory route of administration for CAPD patients.

Absorption↗
PubMed1989

Pharmacokinetics of intraperitoneal ciprofloxacin in patients on CAPD.

The concentration of ciprofloxacin was assayed in plasma and peritoneal dialysate following intraperitoneal administration of the drug in the absence of bacterial peritonitis. After administration of a single dose of 5 mg/kg, ciprofloxacin was rapidly absorbed, producing a peak plasma concentration of 1.9 +/- 0.6 mg/l after 3-4 h with an apparent bioavailability of 0.84. In a separate study, following the administration of 25 mg/l for eight consecutive CAPD cycles the intraperitoneal concentration of ciprofloxacin fell to a mean of 8.4 +/- 4.6 mg/l after 4 h cycles and to a mean of 3.0 +/- 3.2 mg/l after 12 h cycles. During the period of administration the mean plasma concentration was 0.5 +/- 0.2 mg/l. Analysis of dialysate for 48 h after cessation of drug administration demonstrated ciprofloxacin to be present in effluent from only two of the six patients, confirming its poor peritoneal elimination.

Ciprofloxacin↗
PubMed1988

Effects of prolonged naloxone infusion in septic shock.

Fourteen patients suffering sixteen episodes of septic shock requiring inotrope and/or vasopressor support were randomised to receive a 30 micrograms/kg naloxone intravenous bolus followed by a 30 micrograms/kg/h infusion or an equivalent volume placebo bolus and infusion for 8-16 h in a double-blind study. pH and pulmonary wedge pressure were kept constant, and inotrope and/or vasopressor were titrated to maintain a preselected mean blood pressure. Inotrope/vasopressor requirements in the naloxone-treated group were significantly lower than those in the control group at 8 h (eight patients in each group, p less than 0.005) and at 16 h (five patients in each group, p less than 0.02). Late but significant improvements in stroke volume (p less than 0.02) and heart rate (p less than 0.05) were also noted in the eight naloxone-treated patients.

Adult↗
PubMed1987

Simple method of monitoring colonising microbial load in chronic bronchial sepsis: pilot comparison of reduction in colonising microbial load with antibiotics given intermittently and continuously.

Aerobic and anaerobic culture of sputum on selective bacteriological media, combined with a new method of plating and plate reading, permitted rapid identification and quantitation of three genera of bacteria commonly associated with chronic bronchial sepsis (Haemophilus spp, Pseudomonas aeruginosa, and Staphylococcus aureus) and avoided time consuming serial dilution of sputum and subculture of organisms. The accuracy of this new technique was assessed in patients with chronic bronchial sepsis and was used to detect changes in the colonising microbial load of Haemophilus spp and Ps aeruginosa in patients with bronchiectasis receiving one of three different antibiotic regimens: intermittent seven day courses of amoxycillin for exacerbations; or a six month course of continuous oral or nebulised amoxycillin. The colonising microbial load of Haemophilus spp was reduced only temporarily (+++ to ++) after each intermittent course of antibiotic, but a sustained and greater reduction in the colonising microbial load of both Haemophilus spp (+++ to +) and antibiotic resistant P aeruginosa (+++ to +) was seen during both continuous treatments. Sputum purulence decreased in parallel with colonising microbial load, reflecting a reduction in host inflammatory response to the colonising microbial load.

Amoxicillin↗
PubMed1986

Comparison of behavioral treatments for Raynaud's disease.

Induced vasodilation by classical conditioning was compared to biofeedback therapy as treatment for idiopathic Raynaud's disease. Classical conditioning therapy consisted of 54 10-min immersions of both hands in water (43 degrees C) simultaneously with whole-body exposure to cold air (0 degrees C), given three times per day, 3 days per week, for 6 weeks. Biofeedback therapy consisted of eight sessions of electromyograph feedback (frontalis) while listening to relaxation tapes, followed by 10 sessions of digital thermal feedback while listening to relaxation tapes. Both groups received 10-min cold stress tests of whole-body exposure to 0 degrees C before and after treatments. Results indicated that both therapies significantly increased the digital temperature response to cold. Although no differences between classical conditioning and biofeedback were found at the end of training, a 1-year follow-up indicated that classical conditioning was more effective.

Adolescent↗
PubMed1986

The risks and benefits of a low protein-essential amino acid-keto acid diet.

Twelve patients with progressive renal failure were placed on a very low protein diet supplemented by an essential amino acid-keto acid mixture for six to twelve months. Total daily intake was 0.04 g nitrogen/kg and 50 kcal/kg. Eight subjects had a significant change in the slope of reciprocal plasma creatinine, becoming less steep and in two cases positive. GFR did not improve, but in four patients the decline over twelve months was less than 0.5 mliter/min. There were significant falls in blood and urinary urea, serum phosphate PTH and calcium X phosphate product. Body wt decreased during the first three months. Arm muscle circumference fell by 0.9 cm (P less than 0.005). Serum albumin and transferrin levels did not change significantly. Muscle mass and plasma creatinine fell simultaneously in several patients. Creatinine excretion per kg muscle mass, assessed anthropometrically, declined by 21% in the first three months. This diet may slow the decline in renal function in a proportion of patients. However, muscle mass can be lost. Serum protein levels do not accurately reflect nutritional changes. A fall in plasma creatinine may not be due to improved GFR but instead to altered creatinine metabolism.

Adult↗
PubMed1986

Pharmacokinetics of ciprofloxacin in healthy volunteers and patients with impaired kidney function.

The pharmacokinetics of ciprofloxacin were studied, in six healthy controls and in 18 patients with varying degrees of renal impairment, after administration of a single 100 mg intravenous dose. Pharmacokinetic parameters were calculated on a two compartment open model. The mean distribution volume was 2.1 (+/- 0.6) l/kg of ideal body weight; it did not correlate significantly with renal function. In the healthy volunteers 57 (+/- 9)% of the drug was eliminated by the kidney and 43% by other pathways. The renal clearance of ciprofloxacin correlated with creatinine clearance (rs = 0.93, P less than 0.001), and urinary excretion of the drug was markedly reduced in patients with the most severe degrees of renal impairment. Plasma clearance correlated with creatinine clearance (rs = 0.50, P less than 0.02). This together with the lack of correlation between non-renal clearance and renal function enables us to suggest an intravenous dosage schedule for patients with renal impairment.

Adult↗