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Biomedical subjects

J Bower

Publications and source records attributed to J Bower.

At least 37 records · Page 2Linked to original sources
PubMed1988

Enhancement of peritoneal transport in rats by disrupting stagnant fluid films.

Dialysate comes into contact with the active membrane and remains in contact until the fluid is refreshed. This design exaggerates stagnant fluid films. Dialysis rate studies were done to evaluate transport when stagnant fluid films were disrupted. Following anesthesia, 30 mL of commercial 1.5% glucose dialysate containing 100 mg% urea and 25 mg% inulin warmed to 37.5 C were instilled. Dialysate was sampled at 5, 15, 30, 45, and 60 min after instillation. Experimental rats were vibrated at 25 Hz throughout the study. Diffusive mass-transfer coefficients (MTC mL/min 1000 cm2) were calculated, and control and vibrated group means were tested for differences using Student's t-test. The mean MTC values for control (n = 10) and vibrated groups (n = 12), respectively, were: urea 0.8 +/- 0.04, 1.4 +/- 0.2, p less than 0.01; glucose 0.4 +/- 0.03, 0.6 +/- 0.03, p less than 0.01; insulin 0.2 +/- 0.01, 0.2 +/- 0.01, p = NS. Disrupting stagnant fluid films augments peritoneal transport.

Animals↗
PubMed1987

The practice premises.

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Facility Design and Construction↗
PubMed1987

Fungal peritonitis during continuous ambulatory peritoneal dialysis: a report of 17 cases.

Seventeen cases of fungal peritonitis and one case of Nocardia asteroides peritonitis were observed in 141 patients during the first 5 years of our continuous ambulatory peritoneal dialysis program (CAPD). Fungal peritonitis accounted for 7% of the episodes of peritonitis observed in this interval. There were eight deaths associated with fungal peritonitis. In only three instances could factors predisposing to fungal peritonitis be identified. We were unable to predict who would develop fungal peritonitis by analysis of nutritional, demographic, or technical factors associated with the dialysis procedure. The diagnosis of fungal peritonitis was easily established using routine blood agar culture techniques. Successful management of these patients included prompt removal of the Tenckhoff catheter and intravenous (IV) administration of amphotericin.

Amphotericin B↗
PubMed1986

Protein losses and tobramycin absorption in peritonitis treated by hourly peritoneal dialysis.

The effects of peritonitis on dialysate protein losses of IgG, IgA, IgM, transferrin, and complement were investigated. Thirteen patients who developed peritonitis while undergoing peritoneal dialysis were compared with seven noninfected dialysis patients. Dialysate protein losses increased during peritonitis, but IgG, IgA, IgM, transferrin, and complement losses did not. The ratio of the amount of these proteins to the total amount of protein, measured by trichloroacetic acid precipitation, was unaltered by peritonitis, suggesting that albumin is the predominant protein lost during peritonitis. The infected patients absorbed 55% of the administered dose of tobramycin, at 17 mL/min, and the noninfected 44%, at 13 mL/min.

Adolescent↗
PubMed1986

Effect of intraperitoneal insulin on solute kinetics in CAPD: insulin kinetics in CAPD.

The authors evaluated the transport kinetics of insulin and inulin administered intraperitoneally to six diabetic patients undergoing continuous ambulatory peritoneal dialysis. The mass transfer coefficients (MTC) calculated from dialysate to blood for 1.5% and 4.25% dextrose dialysate were (ml/min): insulin 2.9 +/- 0.9, 2.0 +/- 0.5; inulin 3.3 +/- 1.4; 2.9 +/- 1.7, respectively. The MTC for inulin calculated from blood to dialysate was 2.0 +/- 0.7 ml/min. Because insulin disappears from the peritoneal cavity at a rate similar to inulin, it suggests that insulin transport can be defined by diffusion. The derived MTC values for glucose were not altered by the addition of intraperitoneal insulin. The derived MTCs for eight diabetic to thirteen nondiabetic patients were compared. The MTC derived for urea was less among the diabetics (16.6 +/- 2.2 vs. 24.6 +/- 2.6 p less than 0.05), but there were no differences for creatinine, uric acid, glucose, inulin, and protein. The derived values were found to be normally distributed and patients in the upper quartile for one solute were generally in the upper quartile for other solutes.

Ascitic Fluid↗
PubMed1986

The importance of the abdominal viscera to peritoneal transport during peritoneal dialysis in the dog.

The authors sought to evaluate the dialyzing surfaces important for peritoneal dialysis. They reasoned that the most definitive way to evaluate whether any of the gut and associated membranes contributed to transport was to see if transport changed when they were removed. Paired studies measuring rates of peritoneal uptake of glucose, urea, and inulin were carried out in dogs. In the morning, the animals were tested with all peritoneal membranes intact. In the afternoon, the studies were repeated after evisceration. The mass transfer coefficients (MTC ml/min)--glucose (viscera 4.4 +/- 0.7, no viscera 4.9 +/- 0.3)--urea (viscera 16.8 +/- 2.4, no viscera 13.8 +/- 1.0);--inulin (viscera 1.6 +/- 0.6, no viscera 2.2 +/- 0.7) were not changed nor was the amount of mass absorbed significantly different. MTC and peritoneal absorption were unaffected by omentectomy, mesenterectomy, or evisceration. Whether these results were due to nonparticipation of these structures in peritoneal transport or other mechanisms await further studies.

Absorption↗
PubMed1985

A double blind trial of dipyridamole in CAPD.

Since we had previously shown that dipyridamole augmented inulin and glucose clearance during intermittent peritoneal dialysis we sought to extend our study to the patient undergoing continuous ambulatory peritoneal dialysis. We carried out a double blind study in which patients received either 75 mg of active drug or placebo for a 2-week period. At the end of this period the mass transfer coefficients, between plasma and dialysate, were measured for selected solutes. We did not find any drug effect. The results of our first study together with the results of this study suggest that dipyridamole has no place in the chronic management of patients undergoing peritoneal dialysis.

Administration, Oral↗
PubMed1985

Evaluation of a peritoneal dialysis solution containing polymer.

Glucose is used in peritoneal dialysate to produce the gradient for ultrafiltration. The peritoneal membrane's low reflection coefficient for glucose imposes a demand for high transmembrane concentrations, perhaps adding unwanted body burden of glucose. A polymer with a lower permeation rate used as an osmotic agent would circumvent this. We evaluated the mass transfer coefficient (mtc), T1/2 disappearance from the peritoneal cavity and ultrafiltration capabilities of a 900 dalton (Mn) starch derived polymer. We compared an 8% (455 mOsm/L) and a 10% (484 mOsm/L) polymer (Pol) solution to available dialysate solutions containing 2.5% (399 mOsm/L) and 4.25% (491 mOsm/L) X glucose (Glc). The dialysate compositions were otherwise similar. Using a randomized complete block design, 5 anephric dogs maintained on chronic peritoneal dialysis were studied. The mtc (ml/min) was greater for the glucose than the polymer solutions (p less than 0.05): 2.5%-13 and 4.25%-14 vs 8%-5 and 10%-6. The T1/2 disappearance (min) was also greater (p less than 0.05): 2.5% Glc-112 and 4.25% Glc-111 vs 8% Pol-281 and 10% Pol-252. Over a 180 min. period the 2.5% glucose solution generated the least volume of ultrafiltrate (ml, p less than 0.05): 2.5% Glc-113 and 4.25% Glc-589 vs 8% Pol-640; 10% Pol-912. We conclude that the lower permeation rate of the polymer yields ultrafiltration at a lower dialysate osmolality. A polymer solution may be a feasible alternative to glucose.

Animals↗
PubMed1985

The expression of chick alpha A2-crystallin RNA during lens development and transdifferentiation.

During development of the vertebrate lens, the lens epithelium undergoes a final stage of differentiation into lens fibre cells, during which the major lens proteins, the crystallins, are synthesised. Lentoids, comprising clusters of lens fibre cells can also be produced by transdifferentiation from certain non-lens tissues, including neural retina and pigmented retinal epithelium. We have isolated an alpha A2-crystallin genomic probe and used it to study the transcription and processing of alpha A2-crystallin mRNA both during lens development and transdifferentiation. We relate these results to earlier measurements in this laboratory of delta-crystallin transcription and alpha- and delta-crystallin protein synthesis, to compare the expression of these two sets of genes. Tissue specific differences in gene expression were found. delta-crystallin mRNA is transcribed before alpha A2-crystallin RNA in the lens, but after it in transdifferentiating neural retina and pigmented epithelia.

Animals↗
PubMed1985

Substitution of a starch polymer for glucose in peritoneal dialysis.

We compared a starch-derived polymer (molecular weight = 900) as the osmotically active agent in peritoneal dialysate (3 and 6% solutions) to results obtained with commercially available glucose dialysate (1.5 and 4.25%). 12 dogs were dialyzed with glucose for 7 days, and 9 received the polymer for 5 days. For dialysate exchanges with an intraperitoneal residence of 240 min the 1.5 and 3% solutions generated similar volumes of ultrafiltrate as did the 4.25 and 6% solutions. However, for exchanges of 960 min the 1.5% dialysate was significantly reabsorbed when compared to the other dialysate concentrations. The serum polymer concentration increased with continued dialysis. The rate of transfer from dialysate to serum in man must still be determined. The lower diffusivity of the polymer will certainly be evidenced. For certain clinical applications where diminished ultrafiltration occurs, the polymer may be of benefit to man.

Animals↗
PubMed1984

Dialysate flow rate and peritoneal clearance.

We evaluated the influence of dialysate flow rates upon peritoneal clearance of urea, creatine, protein losses into dialysate, glucose disappearance from dialysate, sodium removal from the patient during dialysis, and ultrafiltration rate in 64 patients undergoing intermittent peritoneal dialysis. We evaluated three dialysate flow rates: 2 L/h, 3 L/h, and 4 L/h. All dialysate contained 1.5% glucose. The clearance of urea in milliliters per minute (2-L series 14.0, 3-L series 15.1, 4-L series 17.6) and creatinine in milliliters per minute (2-L series 9.3, 3-L series 10.6, 4-L series 11.6) determined at a dialysate flow rate of 4 L/h was significantly greater than the clearances determined at 3 and 2 L/h of dialysate flow (P less than 0.05). The clearance of glucose from the peritoneal cavity in milliliters per minute (2-L series 6.9, 3-L series 7.9, 4-L series 8.9) was significantly greater for the 4-L series as compared with the 2-L series (P less than 0.05). There were no other significant differences. Neither sex, race, previous episodes of peritonitis, nor etiology of renal failure influenced the results. Given the high cost of dialysate, we recommend dialysate flows of 2 L/h if a patient has a residual renal clearance of 2.5 mL/min. Although increasing dialysate flow rate may compensate for renal clearances significantly less than this, we believe the patient should be offered hemodialysis, continuous cyclic peritoneal dialysis (CCPD), or continuous ambulatory peritoneal dialysis (CAPD).

Creatinine↗
PubMed1983

Antibiotic activity in peritoneal dialysate.

There are few studies investigating whether antibiotics added to 30% glucose concentrate preserve their activity in the delivered dialysate. Using a Drake-Willock proportioning system, samples were obtained from the "to" patient path at ten minutes after starting and at four hours. Samples were tested for minimal inhibitory dilution (MID) against Escherichia coli and Staphylococcus aureus. Antibiotics evaluated included amikacin, tobramycin, gentamicin, cephalothin, cefamandole, moxalactam, ampicillin, penicillin, carbenicillin, and vancomycin. In all antibiotics studied, similar MIDs were obtained at the ten-minute and four-hour samples. Compared to saline, dialysate significantly impaired the antibiotic activity (a difference of two or more tube dilutions) of all antimicrobial agents except amikacin and vancomycin.

Anti-Bacterial Agents↗
PubMed1983

Comparison of home hemodialysis to continuous ambulatory peritoneal dialysis.

We evaluated prospectively various outcome measurements of patients assigned initially to continuous ambulatory peritoneal dialysis (CAPD) and home hemodialysis (HHD) from February 1979 to August 1981 and the causes for failures of the techniques. Morbidity was assessed by time in hospital/time on dialysis. Fifty-six patients were trained for CAPD and 37 for HHD. Those assigned to CAPD experienced an increased frequency of hospitalization (7.5% CAPD, 2.8% HHD, respectively) primarily due to episodes of peritonitis. There was also a higher modality failure rate (43% vs. 16%). However, the groups were not comparable in all respects. For example, the CAPD population included 21 patients with major cardiovascular diseases versus only three in the HHD group. The demographic characteristics of both populations including race, sex, age, income, place of residence, marital status, and education were similar. At the time of this study there is no direct evidence showing that healthy patients otherwise able to perform HHD may be maintained with less morbidity for a prolonged period utilizing CAPD. Therefore, we suggest that HHD is the home method of choice for patients able to proceed with this technique. CAPD may be indicated for patients in whom the period of home dialysis is expected to be relatively short and who would be otherwise unable to carry out home dialysis, for example, patients awaiting transplantation and those unable to be maintained on hemodialysis because of impaired cardiac function. To fully evaluate CAPD as a long-term maintenance therapy, a prospective trial must be performed.

Adult↗
PubMedDate not supplied

Intraperitoneal feeding.

This study evaluated the peritoneal cavity as the sole route for alimentation in 300 g growing rats. Initial studies demonstrated that a solution of high osmolality was required to provide sufficient calories. A nutrient solution was formulated by mixing 20% glucose with electrolytes (10 ml) and 8.5% amino acids with electrolytes (20 ml). Instilling 30 ml of nutrient solution induced an IP volume of 60 ml, which was absorbed in 24 hours. Rats were studied in four groups for 7 days. One group received nutrient solution IP (n = 10); a second group received the same amount PO (n = 10); the third group received electrolytes IP (n = 10); and a fourth group was fed rat chow PO (n = 10). Rats fed this nutrient solution (IP and PO) were acclimatized by administering one third of their required nutrient the first 4 days. On the next 3 days they received two thirds of their required nutrient. Both groups fed nutrient solution (IP and PO) lost 23% body weight. Electrolyte and rat chow fed groups lost 26% and gained 8% of body weight, respectively. Due to the high osmolality (1200 mOsm/L) of this nutrient solution, sufficient food could not be delivered via the peritoneal cavity to adequately feed growing rats. Studies were then initiated to formulate another nutrient solution that contained lipids. This solution (678 mOms/L) contained 20% glucose with electrolytes (10 mls), 8.5% amino acids with electrolytes (20 ml), and 10% lipids without electrolytes (30 ml). Glucose and amino acids contained the same electrolyte concentration.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acids↗