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Biomedical subjects

D B Lee

Publications and source records attributed to D B Lee.

102 records · Page 6Linked to original sources
PubMed1972

Interpretation of positive reactions to Heaf tuberculin test in London schoolchildren.

A study of 289 children aged 12-14 years found to be Heaf test positive at routine testing was made to determine the likely cause of the positive tests. Only 12% of children grade 1 Heaf positive were likely to have had a previous infection with Mycobacterium tuberculosis, 49% were likely to have had infections with atypical mycobacteria, and in 39% no cause for the positive Heaf test was found.The positive Heaf test seems to us to be too sensitive. Both a negative and grade 1 positive should be regarded as not significant and these children given B.C.G. vaccine. Heaf grades 2, 3, and 4 should be regarded as significant and the children investigated for M. tuberculosis infection.

Adolescent↗
PubMedDate not supplied

Objective and subjective observations of low-temperature thermoplastic materials.

There is much more to a therapist's selection of materials for splints than the qualities of conformability and rigidity, although these are important in a busy clinic. As new materials become available, they may replace existing materials in popularity as more therapists become open to trying them.

Biocompatible Materials↗
PubMedDate not supplied

Environmental assessment of water, sediment and plants in the Mankyeong River, ROK.

This study was carried out to evaluate water quality, sediment and plant vegetation in eight tributaries of the Mankyeong River for enhancement of natural purification. Among the tributaries, the Iksancheon water had the highest concentration of BOD, T-N and NH4-N due to inflow of swine wastes from the livestock district. The Yucheon water had the highest level of electrical conductivity and SO4(2-) due to inflow of mis-treated wastewater from industrial districts. The Tabcheon had generally similar concentrations of nitrogen and phosphate to that of the upstream of the Mankyeong River: agricultural activity along the Tabcheon appeared to have little negative influence to the water quality. Among various sediments, concentration of organic matter, nitrogen and phosphate were high in the Iksancheon and the Yucheon due to the livestock wastes and industrial wastes. There were 282 species of plants during summer with 43 aquatic plants, 57 hydrophytes, 178 waterside plants and 4 terrestrial plants. Some plant resources were recommended due to much absorption of nitrogen and phosphate for enhancement of natural purification. C. demersum and H. verticillata were recommended in the submerged aquatic plants, H. dubia, N. indica and N. subinteperrimum in the floating leaf aquatic plants, P. communis, Z. latifolia and T. orientalis in the emerged aquatic plants, C. scutata and P. distichum in the waterside plants.

Agriculture↗
PubMedDate not supplied

Effects of high calcium intake on blood pressure and calcium metabolism in young SHR.

Increased dietary calcium intake in the adult spontaneously hypertensive rat (SHR) has been reported to correct low serum ionized calcium concentration ([Ca++]) and to result in a significant amelioration of the prevailing hypertension. In the present study we examined several parameters of calcium metabolism in young (6-week-old) SHR and compared them with those observed in normotensive Wistar-Kyoto (WKY) rats fed equal amounts of a diet containing normal quantities of calcium (0.4%, wt/wt) for 4 weeks. A separate group of SHR was placed on an equal amount of a high calcium (2.8%, wt/wt) but otherwise identical diet. In SHR and WKY eating a normal calcium diet, serum total calcium concentration was not different, but [Ca++] was lower in SHR (1.58 +/- 0.06 vs 1.91 +/- 0.07 mmol/liter, p less than 0.01). Serum immunoreactive parathyroid hormone (PTH) was increased in some, but not all, SHR. No difference was noted between the two groups in the following parameters: calcium intake, serum 1,25 dihydroxycholecalciferol (1,25(OH)2D3), urinary calcium excretion, fractional stool calcium content ([stool calcium/calcium intake] X 100), and in vitro 45Ca uptake by everted gut sacs constructed from segments of duodenum, mid-jejunum, ileum, and proximal colon. A high calcium diet corrected the abnormal serum [Ca++] and PTH but did not alter the progression or severity of the hypertension in SHR. A lower net weight gain was observed in SHR on a high calcium diet when compared to SHR eating normal calcium diet (9.1 +/- 1.8 vs 27.0 +/- 2.0 g).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMedDate not supplied

Innovative peritoneal dialysis: flow-thru and dialysate regeneration.

As the peritoneal dialysis (PD) patient's residual renal function declines, the dialysis dose must be increased. However, the options for increasing the dose are limited to increasing the number of exchanges and/or the volume of each exchange. A review of the literature indicates that the dialysis dose can be significantly increased by flow-through PD, wherein the dialysate flows continuously into the peritoneal cavity through one catheter and out another and/or by regenerating the spent dialysate, thereby, significantly increasing the dialysate flow rate. Flow-thru PD has been used with and without dialysate regeneration. Regeneration has been used with standard inflow/outflow PD. In nearly all cases, substantially increased clearances over standard PD were obtained with reported urea and creatinine clearances as high as 58 and 48 ml/min, respectively. Applying flow-thru to the PD patient would require two catheters or a dual lumen catheter, and to obtain optimum clearances, the dialysate should be pumped through the peritoneal cavity at a high flow rate. Regenerating the dialysate allows high dialysate flow rates while reducing the total amount of dialysate required. For the continuous ambulatory peritoneal dialysis (CAPD) patient, the unit would have to be wearable; whereas for the patient on automated PD, flow-thru and/or regeneration PD could be incorporated into the equipment. With sorbent regeneration, the protein in the spent PD could be purified and returned to the patient thereby minimizing protein loss, increasing ultrafiltration, and enhancing the removal of protein-bound metabolic toxins.

Humans↗
PubMedDate not supplied

Component selection to optimize blood flow for continuous arteriovenous hemofiltration and dialysis.

Blood flow with an arteriovenous access is limited by the resistance of the catheters and hemofilters or dialyzers in the extracorporeal system. Resistance data from manufacturers are varied as to the test conditions used, however, making it difficult to select optimum components. Furthermore, the same size catheters may have varying inner diameters, resulting in large differences in flow resistance. The pressure at various flow rates was determined using a water manometer. The pressure/flow relationship for catheters gave a curve, whereas the logarithmic function resulted in a straight line with a slope of 1.48. The pressure/flow relationship for hemofilters and dialyzers was a straight line with an intercept close to the origin. The data in the tables for flow resistance at 50 and 100 ml/min can be used to compare the various components, and to estimate flow in a given extracorporeal system.

Blood Flow Velocity↗
PubMedDate not supplied

"Machineless" nutritional hemodialysis.

It was previously demonstrated that with nutritional hemodialysis (NH), an adaptation of continuous arteriovenous hemodialysis (CAVHD), glucose and aminoacids are efficiently transferred from the dialysate to the patient. Intravenous monitors were used to control dialysate flow and ultrafiltration, and a water manometer provided fail-safe operation. Pressure measurements with low flux dialyzers indicated that a gravity system was possible. This observation formed the basis for the current study. Nutrient dialysate was prepared by adding glucose and amino acid to a bicarbonate dialysate. Subsequently, the bicarbonate dialysate was eliminated by reducing the dialysate volume and increasing the glucose concentration. Dialysate flow was controlled with a valve postdialyzer, and ultrafiltration adjusted by varying the height of the dialysate container. At a glucose concentration of 14.4 gm/dl and outflow rate of 3.9 ml/min, 97% of the glucose in the dialysate was transferred to the patient. Compared with intravenous nutrition, NH is as easy to perform, less costly, does not provide fluid, and is inherently fail-safe. As no equipment is required, many patients can be treated simultaneously. "Machineless" NH suggests the possibility of machineless CAVHD, which could provide dialysis and parenteral nutrition to many acute renal failure patients after a major disaster.

Amino Acids↗
PubMedDate not supplied

Pathogenesis of renal calculi in distal renal tubular acidosis. Possible role of parathyroid hormone.

Elevated circulating levels of immunoreactive parathyroid hormone (PTH), hypercalciuria and renal calculi were found in 3 patients with distal renal tubular acidosis (RTA). Treatment with alkali resulted in a fall of PTH toward normal and a reduction in urinary calcium, but the frequency of urolithiasis was unchanged. In one patient in whom prolonged follow-up was possible, a subtotal parathyroidectomy was performed. This was followed by virtual cessation of stone formation despite persistence of the acidification defect. This study suggests that RTA may be associated with secondary hyperparathyroidism and that the consequent elevation in PTH may play a contributory role in the pathogenesis of renal calculi.

Acidosis, Renal Tubular↗