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Biomedical subjects

D G Oreopoulos

Publications and source records attributed to D G Oreopoulos.

At least 307 records · Page 17Linked to original sources
PubMedDate not supplied

Update on continuous ambulatory peritoneal dialysis.

By now many patients have been successfully maintained on CAPD for five years or more, thus demonstrating that CAPD is a viable long-term treatment for end-stage renal disease. Peritonitis--the main concern of the earlier years--is now a less frightening complication. We know better how to treat peritonitis and its incidence has decreased from one episode every 8 months initially to one episode every 18 months now. In addition, several innovations, which have been or soon will be introduced, promise to decrease the frequency of peritonitis to an even lower rate. The problem of peritonitis is now being replaced by the chronic complications of CAPD, predominantly malnutrition and decrease in peritoneal ultrafiltration. CAPD has become an important adjunct in the treatment of children with ESRD, especially the very young. Even though not normal, their growth on CAPD is better than that of children on hemodialysis and as good as that after a successful transplant. CAPD has become a promising treatment for the diabetic with ESRD. This experience has stimulated interest and research in the role of intraperitoneal administration of insulin for blood glucose control. With the present worldwide experience of CAPD, this treatment has ceased to be experimental. A percentage of patients requiring dialysis will be better off on CAPD than on hemodialysis. Even though this percentage will vary among various countries, the nephrologist who wants to provide the best treatment for each patient must be well experienced in and have all treatments at his disposal including CAPD.

Adult↗
PubMedDate not supplied

Peritoneal dialysis in diabetic end-stage renal disease.

There has been a progressive improvement in the survival of diabetics with end-stage renal disease on peritoneal dialysis. Since its introduction in 1976, large numbers of diabetics have been preferentially treated by continuous ambulatory peritoneal dialysis (CAPD). CAPD offers the potential advantage of reduced cardiovascular stress, a steady biochemical state, good control of hypertension and extracellular fluid volume, and intraperitoneal administration of insulin. In addition, peritoneal access is easy to establish, CAPD offers freedom from a machine, and enables travel without upsetting facility dialysis schedules. The effects of intraperitoneal insulin are almost similar to normal insulin secretion. Although limited, the long-term experiences of CAPD in diabetics tend to show lower technique and survival results compared to nondiabetics. The incidence of peritonitis is no different between the diabetics and nondiabetics on CAPD. Continuous clyclic peritoneal dialysis is indicated in those who prefer nightly dialysis or those who are unable to do exchanges during daytime. Intermittent peritoneal dialysis is the least preferred therapy because of its inability to provide adequate dialysis.

Diabetic Nephropathies↗
PubMedDate not supplied

Comparisons between X-ray photodensitometric and gamma-ray absorptiometric findings of bone mineral measurements, and the evidence of their convertibility.

Fifty-two bone mineral measurements were made in chronic renal failure patients using two different radiologic techniques concurrently: gamma-ray absorptiometry; and x-ray photodensitometry. Although the sites of measurements of the cortical bone mineral mass in radius were different (distal vs. proximal) and different parameters were determined (in units of gm/cm vs. gm/cm2), a moderately good correlation was found between measurements by the two techniques (r = 0.61, p less than 0.001). Using external bone width, it was possible to calculate from photodensitometric measurements the bone mass per unit length (gm/cm). This conversion improved the correlation with absorptiometry values considerably (r = 0.78, p less than 0.001). A similar correlation was found between the trabecular bone mass in the distal radius, measured by absorptiometry, and the cortical bone mass in the proximal radius, determined by photodensitometry (r = 0.79, p less than 0.001), the correlation between the cortical and trabecular bone masses by absorptiometry being only slightly higher (r = 0.84, p less than 0.001). The residual variations not explained by the correlations between the absorptiometric and photodensitometric techniques may be largely due to the real differences of bone mineral masses at the two measuring sites and by the inherent methodological errors.

Absorptiometry, Photon↗
PubMedDate not supplied

Changes in volume of peritoneal mesothelial cells exposed to osmotic stress.

OBJECTIVE: To evaluate changes in volume of mesothelial cells exposed to hypertonic medium and the role of volume regulatory mechanisms in adaptation to hyperosmolality. DESIGN: Experiments were performed on primary cultures of human peritoneal mesothelial cells. Cell volume was estimated by measuring equilibrated (intracellular/extracellular space) 14C-urea in cellular water. Cells in monolayers were exposed to hyperosmotic media and changes in cellular water or intracellular uptake of 3H-proline were measured. RESULTS: Exposure of mesothelial cell monolayers to hyperosmotic media reduced the cell volume; the effect was proportional to the osmolality of the medium. Volume of cells exposed to medium supplemented with glucose (180 mmol/L) decreased by 26%, p < 0.001, after 30 minutes' incubation. Prolonged exposure of mesothelial cells to hyperosmotic medium resulted in gradual recovery, after initial decline, of their volume. Intracellular uptake of amino acid 3H-proline increased after 240 minutes' exposure of the mesothelial cells to medium supplemented with glucose (90 mmol/L) (+40%, p < 0.05). When cells cultured for 7 days in medium supplemented with glucose (45 mmol/L) were exposed to medium with low glucose content (5 mmol/L) their volume increased by 17%, p < 0.05. CONCLUSION: Mesothelial cells shrink after exposure to hypertonic medium. Increased intracellular uptake of amino acids may be one of the regulatory mechanisms that ensure subsequent volume increase in these cells. Mesothelial cells chronically exposed to hypertonic medium swell after transfer to a medium with physiologic osmolality.

Cells, Cultured↗
PubMedDate not supplied

Gender differences in normalized clearances in CAPD: role of body size and normalizing parameters.

OBJECTIVE: To compare raw (not normalized) and normalized urea and creatinine clearances between women and men on continuous ambulatory peritoneal dialysis (CAPD). To study whether potential gender differences are due to the normalization process. DESIGN: Retrospective analysis of clearance studies. SETTING: Dialysis units of four academic medical centers. PARTICIPANTS: The study included 302 subjects (135 women and 167 men) on CAPD with four daily exchanges and a 2-L exchange volume. INTERVENTION: Measurement of urea and creatinine clearances (261 in women, 352 in men) by standard methods. Body water (the volume of distribution, V, for both urea and creatinine) was estimated by the Watson anthropometric formulas. MAIN OUTCOME MEASURES: Comparison of raw and normalized clearances between women and men. Urea clearance was normalized by V (Kt/Vur), while creatinine clearances was normalized by both V (Kt/Vcr) and body surface area (BSA) (Ccr). RESULTS: Mean values of weekly total (peritoneal plus renal) raw clearances were higher in men (urea clearance: women 67.1 L, men 77.4 L; Ccr: women 61.7 L, men 78.3 L). Raw renal clearances were higher in men, while raw peritoneal clearances were comparable. Mean weekly total Kt/Vur was higher in women (2.19 vs 1.94 in men), mean weekly total Kt/Vcr did not differ between the genders (women 2.01, men 1.95), while mean weekly Ccr was higher in men (73.0 vs 64.7 L/1.73 m2 in women). When clearances differed, the differences were significant at p < 0.001. Men had greater height and weight, while women had greater body mass index. On the average, V in men exceeded V in women by 31%, while BSA in men exceeded BSA in women by only 12%. CONCLUSIONS: Normalization of clearances by V creates relatively higher clearance values in women, while normalization by BSA creates relatively higher clearance values in men. Thus the normalization process may create artificial differences in the normalized clearances between genders.

Body Constitution↗