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Biomedical subjects

G A Posen

Publications and source records attributed to G A Posen.

17 recordsLinked to original sources
PubMed2000

Initial clinical results with the LifeSite Hemodialysis Access System.

BACKGROUND: The LifeSite Hemodialysis Access System is a subcutaneous valve with an internal pinch clamp that is actuated with a standard 14-gauge dialysis needle, connected to a single lumen cannula placed in the central venous circulation for hemodialysis (HD). METHODS: The LifeSite System (2 valves) was implanted in 23 patients with immediate dual-needle HD use. The cannulas were placed in either the jugular or the subclavian veins and were connected to the subcutaneous valves located in the upper chest area. RESULTS: The mean duration of device survival for the LifeSite System was 6.8 +/- 0.97 months. During this period, the device achieved prescription HD blood flow rates averaging 384.7 +/- 78.5 mL/min with a venous pressure of 223.2 +/- 60.3 mm Hg. After 125 patient months, device removal because of infection was at a rate of 2.5 per 1000 days, and there were no devices removed because of poor flow. The average Kt/V for these patients was 1.51. CONCLUSION: This preliminary clinical study has validated the applicability of the LifeSite Hemodialysis Access System as an access for HD. It is easily implanted and easily used, provides safe and effective dialysis, and is well accepted by patients. It should be especially useful as a bridge device to allow for maturation of a native fistula and will provide an alternative for long-term use in patients in whom a peripheral dialysis access is not feasible.

Adult↗
PubMed1991

Oral iron absorption in hemodialysis patients treated with erythropoietin.

The effect of the erythropoietic activity of the bone marrow on oral iron absorption was investigated in hemodialysis patients. The subjects were enrolled in the Canadian Multicentre Erythropoietin (EPO) Trial; four patients were in the placebo group and four were in the EPO group. All patients were maintained iron replete with oral and intravenous iron as required to maintain ferritin greater than 200 micrograms/L. All patients had two oral radio-labelled iron (59Fe) absorption tests. The first took place during the last two months of the EPO trial, and the second within the first three months of the maintenance phase where all patients received EPO. The erythropoietic activity of the bone marrow was changed by administration of EPO to the placebo group. The group with an unchanged EPO prescription served as controls. The placebo group absorbed 4.5% and 3.9% of 59Fe pre- and post-EPO, respectively (delta NS). The control group absorbed 3.2% and 4.4% of 59Fe and thus similarly showed no change in iron absorption. Oral iron absorption is low in hemodialysis patients, and is not augmented by short-term EPO therapy. The high level of iron stores (i.e., ferritin) present in the Canadian EPO study patients may prevent an effect of the erythropoietic stimulation on iron absorption. Although an increase in iron absorption by EPO was not demonstrated, a type II error could not be excluded.

Adult↗
PubMed1990

Results from the Canadian Renal Failure Registry.

This report encompasses data collected from all Canadian patients starting treatment for end-stage renal failure (ESRF) from 1981 until the end of 1987. Gross mortality showed an initial decline, but has stabilized since 1985. The year of entry into the system did not change the survival rate. There was an increase in the rate of acceptance of new patients between 1982 and 1987. The largest increases were in the older age groups, and resulted in a concomitant increase in the number of registered patients in older age groups. Survival on dialysis by age group declined with age. There was no difference in patient survival on hemodialysis or peritoneal dialysis. The probability of death for all patients entering the ESRF system remained constant notwithstanding year of entry into the system. It was slightly higher for males than females, much higher for patients with diabetes or renal vascular disease, higher with age, and much higher for patients not undergoing transplant.

Adolescent↗
PubMed1986

Kidney transplantation in Canada, 1981-84.

The Canadian Renal Failure Register was established in 1980. Data have been collected annually for all Canadian patients in whom irreversible kidney failure developed and who required dialysis or transplantation. The authors present actuarial patient and graft survival rates for 1981-84. In 1984, patients with a functioning renal graft accounted for 43.9% of the patients with end-stage renal disease. The number of transplants performed increased from 482 in 1981 to 662 in 1984; however, 1,022 patients undergoing dialysis (25.2%) were on an active waiting list for a transplant at the end of 1984. Greater effort is needed to increase the transplantation rate.

Actuarial Analysis↗
PubMed1977

Ribonuclease activity in renal failure: evidence for toxicity.

The normal level of serum or plasma poly C-avid ribonuclease activity is 1047 +/- 247 U/mL. Serum levels increase proportionately with elevations in serum creatinine, reaching levels of 9,500-35,000 in patients undergoing dialysis. The levels can be normalised by successful renal transplantation but not by dialysis. Purified human urinary ribonuclease, a glycoprotein enzyme similar to the serum ribonuclease, was capable of: 1) inhibiting the incorporation of 3H-thymidine into mitogen-stimulated lymphocytes; 2) inhibiting the proliferation and growth of bone marrow red cell colonies; and 3) adversely affecting the growth and viability of precursor fat cells.

Cell Division↗
PubMed1975

Beneficial effect of hemodialysis on renal allograft survival.

The effect of the length of hemodialysis on the outcome of renal transplant was evaluated in 43 recipients of renal allograft. 22 out of 23 patients (95.7%) dialyzed for longer than one year had an excellent renal function at one year, while only 10 out of 20 patients (50%) dialyzed for less than one year had good renal function at one year. Only one kidney (4.3%) was lost due to rejection in the first group, while 10 kidneys (50%) failed to function because of severe rejection in the second group. The length of hemodialysis appears to have a beneficial effect on graft survival, but the mechanism by which it exerts this effect is not clear.

Adolescent↗
PubMed1972

Permanent neurological sequelae despite haemodialysis for lithium intoxication.

THREE PATIENTS WITH LITHIUM TOXICITY ARE REPORTED, TWO OF WHOM WERE EXPOSED TO TOXIC LITHIUM LEVELS FOR A PROLONGED PERIOD: both survived with permanent damage to basal ganglia and cerebellar connexions despite effective lowering of lithium levels by haemodialysis. Data obtained during dialysis treatment show prolonged haemodialysis to be the treatment of choice. If facilities for haemodialysis are not available or the patient presents with toxic lithium levels and minimal symptoms peritoneal dialysis will effectively lower serum lithium levels, but more slowly than haemodialysis.

Basal Ganglia↗