Biomedical subjects
Publications and source records attributed to T Manning.
A procedure for separating barbiturates by reverse-phase TLC is described. A spotted TLC plate is dipped in mineral oil/petroleum ether (1:10) and run 15 cm in a solvent of water/methanol/ammonium hydroxide, (80:20:2). After visualization, the drugs tested showed distinct separation.
The increased use and abuse of methadone in recent years has posed a problem of both its identification and quantitation in body tissues. Recent development of a radioimmunoassay for methadone appears to have solved the problem. In our hands the assay was extremely sensitive and specific. It also appears to be an excellent tool when quantitative estimates are to be obtained. Although it initially appears to be relatively expensive, the time saved in doing a complete tissue distribution equalizes the cost. It is hoped that other radioimmunoassays currently under development will prove as satisfactory.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
A comprehensive experimental design was developed to study the effects of thermal degradation products formed by the combustion of building materials on the behavior of rats. Three materials were studied. They were Douglas fir, wool, and polyvinyl chloride. Each material was tested under both flaming and nonflaming modes of combustion. The smoke and gases produced by each material were analyzed by specific gas detector tubes, gas chromatography/mass spectrometry, and infrared spectroscopy. Products measured during combustion included oxygen, carbon monoxide, carbon dioxide, hydrogen cyanide, and hydrocarbons. Part of a much larger study, this paper will deal with the analytical aspects of the experimental design.
The pharmacokinetics of a single intravenous dose of digoxin in the guinea pig was investigated with emphasis on the penetration of digoxin into the vitreous humor. A controlled study was undertaken and data was collected which indicated that digoxin follows an open, two-compartment pharmacokinetic model with a terminal half-life of 318 minutes. The data indicated that the ratio of vitreous concentrations to serum concentrations were determined to be equal following an initial tissue distribution phase.
Explore the source record for details and available documents.
To define the biomechanical effects of total lateral meniscectomy and of subsequent lateral meniscal allograft replacement on load transmission and distribution across the human knee, we mounted 10 fresh-frozen young human cadaveric knees on a mechanical testing system. Peak pressure and contact area profiles were determined at 0 degrees, 30 degrees, and 60 degrees of knee flexion using pressure-sensitive film and a densitometer. Load transmission profiles were determined for each knee in a sequential test order: 1) intact knee, 2) after lateral meniscectomy, 3) after implantation of size-matched meniscal allograft fixed with bone plugs, and 4) after release of the anterior and posterior horn attachments of the allograft. Total lateral meniscectomy resulted in a 45% to 50% decrease in total contact area. Allograft replacement increased total contact area by 42% to 65% as compared with total meniscectomy at all flexion angles. After release of the anterior and posterior horn attachments, contact area was identical to that after total meniscectomy. Total lateral meniscectomy resulted in a 235% to 335% increase in peak local contact pressure. Allograft replacement decreased these pressures by 55% to 65% at all flexion angles, but they remained significantly greater than those in the intact state. After release of the anterior and posterior horn attachments, contact pressures were identical to those after total meniscectomy. Compared with total meniscectomy, meniscal allograft transplantation significantly increases contact area and decreases peak local contact pressures, but any biomechanical advantages are lost without bone plug fixation of the anterior and posterior horns.
This study was undertaken to determine the contribution of various structures in the posterior cruciate ligament-deficient knee in resisting posterior tibial translation. With "isolated" injuries to the posterior cruciate ligament, the amount of posterior translation will decrease with the posterior drawer test as the knee is taken from neutral to internal tibial rotation. The present study was performed to conclusively determine the anatomic structure responsible for this clinical observation. The TestStar device was used to perform single-plane posterior drawer tests in 14 cadaveric knee specimens. The tests were performed with the knee in neutral tibial rotation and in 20 degrees of internal tibial rotation. The intact knee was tested and then the knee was tested after sequential sectioning of the meniscofemoral ligaments, the posterior cruciate ligament, the posteromedial capsule, and the superficial medial collateral ligament. With the knee in neutral rotation, posterior translation continued to increase as each structure was sectioned. With the knee in internal tibial rotation, posterior displacement was significantly less than in neutral rotation for each state until the superficial medial collateral ligament was sectioned; posterior translation was increased after its sectioning. Our data demonstrate that the superficial medial collateral ligament is the structure responsible for a decrease in posterior tibial translation in the posterior cruciate ligament-deficient knee.
To evaluate the effects of electrical stimulation on the mechanical properties of healing skin, 20 Hanford mini-pigs weighing 10-15 kg with trochanteric pressure ulcers were subjected to electrical stimulation. Examination of the biomechanical properties of the skin and changes in wound area and volume was done on previously wounded and healing pigskin subject to AC or DC electrical stimulation. The behavior of normal pigskin was compared to (1) denervated controls, (2) denervated AC-stimulated skin, and (3) denervated DC-stimulated skin. A denervated limb trochanteric pressure sore model developed in house permitted the use of a 6.5-mm percutaneous cancellous screw for wound formation and a 3-cm-diameter spring compression indentor to create reproducible and uniformly controlled grade 3 or higher tissue ulcers in the monoplegic hind limbs. Denervation was accomplished by right unilateral extradural rhizotomies from L2 to S1 nerve roots. Electrodes were placed 1 cm distal and proximal to the wound periphery, and wounds were stimulated 2 h/day, 5 days/week for 30 days. Dumbbell-shaped skin specimens with a length to width ratio of 3:1 were uniaxially loaded in tension until failure at an extension rate of 150 mm/min. The stiffness values for skin samples oriented parallel to the current flow were reduced by nearly half the values obtained for normal controls. Statistical differences (P < .05) were found for stress, Young modulus, and stiffness when compared to normal skin. Samples oriented in the perpendicular direction were comparable to normal skin (P = NS).(ABSTRACT TRUNCATED AT 250 WORDS)
UNLABELLED: This study examines the frequency of discrepancy between Kt/V urea and creatinine clearance (Ccr) measurements in patients on peritoneal dialysis (PD) and the reasons for this discrepancy. DESIGN: Nonrandomized, retrospective data analysis. SETTING: Single PD unit of a university teaching hospital. PATIENTS: All adult patients receiving PD at our center from January 1995 to December 1996. METHODS: Actual (a) and desired (d) body weight (BW) were used to calculate urea volume of distribution (V) and body surface area (BSA). Patients were divided into four groups based upon their total small solute clearances (Kt/V and Ccr, normalized by actual weight) and three additional groups based upon actual/desired (a/d) body weight ratio. An additional analysis was performed for the subset of anuric patients. Data collected for all patients included the following: total Kt, total Ccr, 4-hour dialysate/ plasma (D/P) creatinine, serum albumin concentration, duration of PD, actual body weight, age, and height. RESULTS: Twenty-three percent of the clearance measurements in our study were discrepant, defined as having values for either Kt/V or Ccr (but not both) above the accepted targets of Kt/V > or = 2.0/wk and Ccr > or = 60 L/wk/ 1.73 m2. Patients with both values above target are more likely to have higher residual renal function. Patients who are significantly less than BWd and patients on PD for a longer time are more likely to have adequate Kt/V but not Ccr. Furthermore, patients who are less than 90% or greater than 110% of BWd have markedly different values for Kt/V and Ccr when BWa versus BWd values are used. CONCLUSIONS: Kt/V and Ccr values are frequently discrepant; a number of factors affect these two measurements to varying degrees, including weight, degree of residual renal function, and duration of PD.
Explore the source record for details and available documents.