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Biomedical subjects

T B Wiegmann

Publications and source records attributed to T B Wiegmann.

47 records · Page 3Linked to original sources

Use of an extracorporeal arterio-venous shunt and capillary tubes for frequent micro-blood sampling in rats.

Because of the importance of frequent sampling during kinetic analysis, we have developed a method that permits frequent, reliable, and rapid access to the blood stream in rats. The method comprises the establishment of an extracorporeal arterio-venous shunt between femoral blood vessels. Quantitative samples of whole blood and plasma are obtained with capillary micro hematocrit tubes. The small sample volume permits repetitive analysis without major changes in hematocrit. There is good agreement between these measures and ordinary pipetting techniques. Kinetic analysis showed good resolution with close correspondence between actual measurements and the final curve of best fit. This method could be employed advantageously in small conscious animals, when frequent small samples are required by experimental design.

Animals↗

Home dialysis and dialysis treatment modalities in the VA system.

A questionnaire was sent to 50 Veterans Administration dialysis centers to inquire about treatment utilization in preparation for a Cooperative Dialysis Study. Thirty-five completed questionnaires in this survey identified a dialysis population of 2,483 patients including 452 contract patients (13.5%). The number of patients treated in-center was 1,101 (48.5%), including 239 on self-care (10.2%), and 930 patients (38.0%) were dialyzed at home. This high utilization rate of home dialysis appears in excess of three times the prevalence of home dialysis experienced overall in non-VA programs. Identification of factors responsible for the present emphasis on home programs in the VA and a corresponding analysis of non-VA programs should provide important information for the planning of future national ESRD policies.

Ambulatory Care Facilities↗

The dilemmas of patient treatment for end-stage renal disease.

In past years, physicians responsible for the treatment of chronic uremia have faced dilemmas that have been methodologic and economic while attempting to provide good patient care. These have been overcome, but in the course of time a larger one has developed. The current dilemma is one of high costs for end-stage renal disease (ESRD) management and the failure of current treatment programs to adequately rehabilitate the ESRD patient. In spite of widespread concern about this dilemma, few current data and even fewer projections exist about the eventual costs for their care. Existing data demonstrate several problems that are the basis of this dilemma: (1) the projections of incidence and prevalence of ESRD patients have been too low; (2) renal transplantation has failed to develop into a dominant (and least costly) form of ESRD therapy; (3) home dialysis programs have failed to offset the rapidly expanding in-center dialysis population; and (4) prevalence of and costs for chronic hemodialysis have increased far beyond expected levels. Using current data for the US population as to the incidence and overall mortality rate of ESRD patients, it is apparent that the dialysis population is only 39% of the way toward a steady state-corresponding to only the 4th year of a calculated 25-year growth curve. Although the current costs for maintenance of ESRD patients exceeds $1.3 billion, based upon such projections with the current distribution of patient treatment modalities, the overall annual cost will be in excess of $3.3 billion before a steady state is achieved. Improvement in mortality rates or increases in the incidence of patients will increase the steady state prevalence and the overall costs. Renal transplantation, unless kidney survival rate is increased so that it approximates patient survival, is unlikely to offset the rapidly increasing costs. New technology that would reduce the costs for center-based chronic hemodialysis has not been identified. Emphasis upon home dialysis modalities as a method of increasing patient rehabilitation and reducing costs appears to be a short-term necessity. Increased research and development in prevention of ESRD and in achieving better transplant kidney survival appear to be extremely important as long-term goals.

Ambulatory Care Facilities↗

Regional citrate anticoagulation in chronic hemodialysis patients.

The pronounced leukopenia caused by cuprophane dialyzer membranes was significantly blunted by citrate regional anticoagulation. Cellulose acetate produced less leukopenia than the cuprophane, regardless of anticoagulant. The pO2 response to the initiation of hemodialysis was not affected by dialyzer membrane or anticoagulant choice. We therefore conclude that citrate anticoagulation reduces dialyzer-induced leukopenia. Citrate anticoagulation does not, however, change the hypoxemia present with acetate dialysis. The dissociation of leukopenia and hypoxemia with citrate anticoagulation suggests that pulmonary sequestration is not a major cause of hypoxemia during hemodialysis.

Anticoagulants↗

Acute polyuric renal failure after aspirin intoxication.

Reversible acute polyuric renal failure was observed in a patient after the ingestion of an unusually large toxic (125 g) dose of aspirin. Renal dysfunction occurred in the absence of volume depletion or underlying renal impairment. These observations emphasize the need for careful monitoring of renal function in all patients with aspirin intoxication.

Acute Kidney Injury↗

Intestinal absorption and secretion of radioactive vanadium (48VO3-) in rats and effect of Al(OH)3.

Vanadium in the metavanadate form (VO3-) is a powerful inhibitor of Na+, K+-ATPase. Because of the similarity between the oxy anions of vanadium and phosphorus, it was of interest to see whether Al(OH)3 would restrict the intestinal absorption of vanadium, as it does that of phosphorus. VO3- was extensively bound to a suspension of Al(OH)3 at pH 5-8. Sprague-Dawley rats (180-300 g) were fasted overnight and gavaged with 5 mumol Na3 VO4 in 1.0 ml 0.9% NaCl containing 1 microCi 48V. Control animals (n = 12) simultaneously received 1.0 ml diluent and experimental animals (n = 12) received 1 ml Al(OH))3. Diluent and Al(OH)3 were then given daily for 4 d. Urine and feces were collected separately each day. In control animals total 48V recovery (stool and urine) over 4 d was 86.6 +/- 2.4% of the administered dose. Although Al(OH)3 insignificantly increased total 48V recovery (93.6 +/- 3.2%), it markedly increased excretion of 48V in the stool as compared to the urine (control: stool, 69.1 +/- 1.8%; urine, 12.5 +/- 1.3%; Al(OH)3: stool, 85.7 +/- 1.5%; urine, 7.9 +/- 1.8%). Animals were then sacrificed and tissue uptake of tracer measured. The pattern of unexcreted 48V in tissue of both groups was kidney greater than bone greater than liver greater than intestine greater than muscle, but the tissue levels were uniformly higher in controls than in Al(OH)3-treated animals. The ability of Al(OH)3 to remove endogenous VO3- was also examined. 48V was injected ip (n = 20). Half of the animals received diluent and half received 1.0 ml Al(OH)3 by gavage daily for 4 d. There were no differences in the pattern of 48V tissue distribution and excretion. It is concluded that Al(OH)3 may prevent tissue accumulation of VO3- from dietary sources by reducing intestinal VO3- absorption.

Aluminum Hydroxide↗

The effect of water loading on albumin excretion in type I diabetes mellitus.

An increased albumin excretion rate is recognized as an important early marker for incipient kidney disease in patients with diabetes mellitus. Many different techniques have been used, and a single void technique has been proposed as the simplest method for screening for increased albumin excretion. We evaluated a previous observation that single void samples during water diuresis yield increased albumin excretion rates. Timed day, night, and 24 hour albumin excretion rates (AER) were obtained in 35 patients with Type I diabetes mellitus. This was followed by examination of 8 consecutive half-hour specimens obtained during continued water diuresis. We compared 26 patients with low AER (less than 20 micrograms/min/24 hr sample) to 9 patients with high AER (greater than 20 and less than 200 micrograms/min/24 hr). Sampling began 60 min after the initiation of the waterload. At first, the AER in the low AER group was significantly higher than it was at night, but it decreased over 60 to 90 min of sampling to levels comparable with daytime AER. This was paralleled by a similar pattern in urine flow rate, sodium, and solute excretion. The AER in the high AER group did not increase with the water load and remained high throughout the study periods. The pattern of urine flow rate, sodium, and solute excretion was similar to that of the group with low AER. The study demonstrates that early sampling after water-induced diuresis leads to overestimation of AER in patients with low AER as compared to patients with high AER.(ABSTRACT TRUNCATED AT 250 WORDS)

Albuminuria↗