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Biomedical subjects

R I Lynn

Publications and source records attributed to R I Lynn.

At least 19 recordsLinked to original sources
PubMed2000

Body composition assessed by neutron activation analysis in dialysis patients.

Malnutrition is prevalent in end-stage renal disease (ESRD) patients treated with hemodialysis (HD) and peritoneal dialysis (PD). In addition, there is increased incidence of morbidity in this group. Evaluation of nutritional status is important. Application of body composition in the ESRD population to evaluate body compartments and to assess nutritional health has become more common in clinical practice. Neutron activation analysis (NAA) may provide data on metabolically active tissue by quantification of total body potassium (TBK) for body cell mass and assessment of protein by total body nitrogen (TBN). This method may be able to detect changes in body composition before clinical signs of malnutrition are apparent. Ten HD (5 male and 5 female) and 10 PD patients (7 male and 3 female) were evaluated by NAA, TBK, and isotope dilution. Female PD patients had an increased total body water (TBW) and increased intracellular water compared to HD females. Albumin was lower in PD women. There was no significant difference between PD men and laboratory controls in TBW, extracellular water, and TBN. The clinical application of body composition methods for evaluation of dialysis patients by serial assessment and for development of a bedside tool needs further study.

Adult↗
PubMed1998

Percentage body fat determination in hemodialysis and peritoneal dialysis patients: a comparison.

OBJECTIVE: To evaluate percentage body fat in hemodialysis (HD) and peritoneal dialysis (PD) patients. DESIGN: A prospective study of 20 HD patients and 20 PD patients. SETTING: Sol Goldman Renal Therapy Center, Lenox Hill Hospital, New York, NY; Baumritter Kidney Center Albert Einstein College of Medicine, Bronx, NY; Body Composition Unit, St Luke's Roosevelt Hospital, Columbia University, New York, NY. PATIENTS: Twenty HD (10 men, 10 women) patients, mean age 41.8 +/- 2.4 years and 20 PD (12 men, 8 women) patients, mean age 48.6 years +/- 3.0 years. INTERVENTION: This is a noninterventional study. PATIENTS signed consent to undergo dual-energy x-ray absorptiometry, total body potassium counting bioelectrical impedance analysis, total body water determination, and anthropmetric evaluation. MAIN OUTCOME MEASURES: Present and compare percentage body fat between HD and PD patients as determined by the methods used. RESULTS: Percentage fat is not different between HD and PD patients. Differences in absolute values of percent fat between techniques exist. CONCLUSION: HD patients and PD patients may be evaluated by the methods of body composition used. Percentage body fat will vary among techniques; therefore the same method should be used to follow a patient over time.

Absorptiometry, Photon↗
PubMed1997

An evaluation of the effectiveness of oral iron therapy in hemodialysis patients receiving recombinant human erythropoietin.

Iron balance is critical for adequate erythropoiesis in hemodialysis patients treated with recombinant human erythropoietin (EPO). The role of oral iron therapy in maintaining or replenishing iron stores has not yet been well defined in such patients. We undertook a double-blind, placebo-controlled study to evaluate the efficacy of oral iron in 49 hemodialysis patients, divided into two groups, based on adequate or deficient iron stores. These groups were treated for 3 months with 150 mg elemental iron (Polysaccharide complex, Central Pharmaceuticals) or placebo, twice daily. Laboratory parameters were followed for five months. These parameters included: hematocrit (Hct), ferritin, transferrin saturation (Tsat), and zinc protoporphyrin (ZPP). A side-effects questionnaire was recorded monthly. Our results indicate that iron replete patients show evidence of falling iron stores during the study period; this observation was identical in both oral iron and placebo subgroups. Iron deficient patients had a significantly greater drop-out rate due to side effects when compared to iron replete patients (33% vs. 8%), despite equivalent responses to the side-effect questionnaire. We conclude: 1) Oral iron fails to maintain iron stores in iron replete patients; 2) Iron deficiency observed in this study may be due to poor medication compliance rather than side-effects.

Administration, Oral↗
PubMed1996

Comparison of five body-composition methods in peritoneal dialysis patients.

Body-composition assessment is an important method of evaluating nutritional status in peritoneal dialysis patients. Because body-composition measurement estimates have not been fully validated in this population, we assessed five body-composition methods in 30 well-dialyzed peritoneal dialysis patients. The techniques studied included bioelectrical impedance analysis, dual-energy X-ray absorptiometry, total-body potassium counting, and anthropometry by two techniques. The dialysis patients were matched for age, race, sex, height, weight, and body mass index with 29 healthy control subjects in our laboratory database. By 5 x 2 x 2 analysis of variance, significant differences were found between results by modality (P < 0.0001) as well as by sex, with women having an increased percentage of fat (P < 0.0001). However, there was no significant intermethod difference by condition (peritoneal dialysis or control). That is, although significantly different percentage fat values were found between the body-composition techniques, this variability was independent of whether the measurement was made on control or peritoneal dialysis patients. Despite the differences between modalities, all techniques were found to correlate significantly with each other (P < 0.01 or better for men and P < 0.001 or better for women). Our experience shows that these routine techniques for measuring body composition can be readily applied to stable peritoneal dialysis patients.

Absorptiometry, Photon↗
PubMed1995

The utility of zinc protoporphyrin for predicting the need for intravenous iron therapy in hemodialysis patients.

The optimal method for diagnosing iron deficiency in end-stage renal disease is an area of controversy. This study compared the use of zinc protoporphyrin (ZPP) with the use of conventional tests for determination of iron deficiency when evaluating the need for intravenous iron therapy in hemodialysis patients maintained on erythropoietin (EPO). A baseline survey was performed in all hemodialysis patients at the Baumritter Kidney Center (Bronx, NY), measuring ZPP, ferritin, transferrin saturation (TSAT), mean corpuscular volume, and hematocrit. Patients with ZPP > or = 90 mumol/mol heme or ferritin less than 100 ng/mL were considered likely to be iron deficient and were treated with 1,000 mg of intravenous iron dextran over 10 hemodialysis treatments. The positive predictive values of ferritin and ZPP for predicting a response to intravenous iron dextran were similar (73% v 83%, respectively; two-tailed, P = 0.48). To determine the sensitivity and specificity of the tests, patients were divided into two groups at the end of the study period: those in whom iron therapy was required (n = 23) (patients treated with intravenous iron dextran who had a 5% increase in hematocrit or a decrease in erythropoietin dose of > or = 2,000 U/treatment) and those in whom iron therapy was not required (n = 24) (patients either treated with intravenous iron dextran without a response [n = 9] or patients whose initial ZPP and ferritin levels were not suggestive of iron deficiency and who maintained a stable hematocrit and erythropoietin dose during the study period [n = 15]).(ABSTRACT TRUNCATED AT 250 WORDS)

Anemia↗
PubMed1995

Bioelectrical impedance analysis and dual energy x-ray absorptiometry to monitor nutritional status.

There exists an imperative to monitor changes in body composition in all dialysis patients on a regular basis to avoid overt malnutrition. In this regard, the absolute measurement of the fat-free mass assessment may not be as crucial as the serial measurement of fat-free mass with the same modality. A significant difference in measured fat and fat-free mass should be expected if different techniques are employed. Therefore, when attempting to monitor patients over time or to assess the effects of changes in therapeutic regimens, a single methodology should be employed. Our data validate the use of BIA in the stable PD patient, indicating that BIA can predict the DXA results. Considering the ease with which BIA measurements can be obtained and the lack of dependency on operator interpretation, BIA is an ideal technique for use in the clinical setting. The applicability of this technique for use in monitoring longitudinal changes in body composition has, in fact, been well established (25, 30, 31). BIA appears to be an excellent method for routine fat-free mass measurement in dialysis patients. In as much as malnutrition continues to remain a significant problem in PD patients, measuring and monitoring body composition is strongly recommended.

Absorptiometry, Photon↗
PubMed1995

Long-term high dose intravenous calcitriol therapy in end-stage renal disease patients with severe secondary hyperparathyroidism.

We prospectively studied the long-term effects of intravenous calcitriol in 17 hemodialysis patients with severe secondary hyperparathyroidism (HPT) for 25.7 +/- 3.4 (+/- SE) months. Calcitriol was given thrice weekly after dialysis. Subsequently, changes were made every 3-4 weeks based upon serum chemistries. Total calcium and inorganic phosphorus were measured weekly; alkaline phosphatase (AP) and IRMA-PTH were measured monthly. Inorganic phosphate was controlled with calcium supplements. With calcitriol therapy both IRMA-PTH and AP decreased from 876 +/- 113 to 65 +/- 13 pg/ml (p < or = 0.001) and 432 +/- 106 to 103 +/- 15 U/ml (p < or = 0.001), respectively. Each patient had a reduction in IRMA-PTH and AP. Nadir IRMA-PTH occurred at 55.4 +/- 7.3 weeks. The maximum and mean maximum doses of calcitriol were 8.0 and 4.1 +/- 0.4 micrograms thrice weekly, respectively. Hypercalcemia tended to occur in those patients who were hypercalcemic prior to the initiation of intravenous calcitriol therapy. All hypercalcemic episodes were asymptomatic and reversed either by temporary withdrawal or lowering of the calcitriol dose. Hyperphosphatemia developed in those patients with a history of elevated serum phosphates and was mostly related to dietary and medication noncompliance. We conclude that intravenous calcitriol was uniformly effective and safe for the long-term therapy of severe HPT in ESRD. Careful attention to serum phosphate control is required.

Calcitriol↗
PubMed1995

The efficacy of iron dextran for the treatment of iron deficiency in hemodialysis patients.

We prospectively evaluated the efficacy of intravenous iron dextran for the replacement of iron stores in iron deficient hemodialysis patients. Twenty-eight patients with serum ferritin < 100 ng/ml were treated with 100 mg intravenous iron dextran for ten consecutive hemodialysis treatments. Therapy was considered successful if the serum ferritin remained > 100 ng/ml for 4 months after treatment. Mean hematocrit increased from 29.1 +/- 0.9% at baseline to 33.6 +/- 1.8% at ten weeks (p < 0.05). The mean erythropoietin dose decreased from 94.1 +/- 5.3 U/kg body weight per treatment at baseline to 82.6 +/- 4.4 U/kg body weight per treatment at 10 weeks (p < 0.05). The mean serum ferritin at baseline was 38.3 +/- 5.5 ng/ml, at 2 weeks 135.9 +/- 19.7 ng/ml, at 6 weeks 114.1 +/- 22.4 ng/ml, and 86.6 +/- 17.7 ng/ml at 10 weeks. The number of patients at the therapeutic target (serum ferritin > 100 ng/ml) was 13 of 28 at 2 weeks after therapy, 9 of 28 at 6 weeks, and 8 of 28 at 10 weeks. The initial serum ferritin was the variable most predictive of successful therapy. None of 15 patients with baseline serum ferritin less than 28 ng/ml had a serum ferritin > 100 ng/ml at 4 months, compared with 8 of 13 (61%) with initial ferritins > or = 28 ng/ml. Baseline hematocrit and transferrin saturation were not predictive of therapeutic success. In summary, this regimen for administration of intravenous iron dextran resulted in improved erythropoiesis, however, at study completion iron stores remained inadequate in the majority of patients. Baseline serum ferritin < 28 ng/ml was highly predictive of patients who failed to reach the therapeutic target.

Anemia↗
PubMed1991

Interstitial nephritis in a patient receiving adoptive immunotherapy with recombinant interleukin-2 and lymphokine-activated killer cells.

A patient receiving adoptive immunotherapy with recombinant interleukin-2 (IL-2) and lymphokine-activated killer (LAK) cells for metastatic melanoma developed acute renal insufficiency out of proportion to the decrease in her renal perfusion after 4 days of receiving IL-2. On the 8th day of IL-2 and the 3rd day of LAK cell infusion she expired suddenly from an acute intra-abdominal hemorrhage due to rupture of a metastasis. Postmortem examination of the kidneys showed an interstitial infiltrate consisting largely of lymphocytes and concomitant tubulitis. Immunoperoxidase staining of the infiltrating cells with a panel of lymphocyte-specific monoclonal antibodies showed the majority of cells to be T lymphocytes (70-75%), with a more focal infiltrate of B lymphocytes (25-30%) and rare monocytes, granulocytes and natural killer cells. This patient represents the first reported case of acute interstitial nephritis associated with IL-2 immunotherapy. Our finding is consistent with the hypothesis that the acute renal failure that accompanies this therapy may sometimes be due to intrinsic renal disease as well as the usual pre-renal failure. Nephritis may be caused by IL-2-mediated effects on lymphocytes, resulting in renal parenchymal infiltration.

Acute Kidney Injury↗
PubMed1990

Adaptations in the diaphragm's in vitro force-length relationship in patients on continuous ambulatory peritoneal dialysis.

In patients on continuous ambulatory peritoneal dialysis (CAPD) for more than 6 wk, we measured functional residual capacity (FRC), maximum inspiratory and transdiaphragmatic pressure, diaphragm length, and radius of curvature (roentgenographic methods) as functions of the volume of peritoneal dialysate (PD) instilled within the abdominal cavity. This allowed in vivo characterization of the human diaphragm's force-length relationship. As PD volume increased from zero to 3 L, FRC decreased from 2.41 +/- 0.29 L to 1.93 +/- 0.072 L; mean total diaphragm length index (TDLI) increased from 0.22 +/- 0.01 to 0.28 +/- 0.01, and diaphragm radius of curvature remained unchanged. Respiratory muscle strength increased as a function of dialysate volume, reaching its maximum after the infusion of 3 L PD. In contrast, normal subjects achieved maximal inspiratory muscle force at their normal FRC, with a mean TDLI of 0.26 +/- 0.01 and showed no further increase as the diaphragm lengthened. We conclude that the human diaphragm may be capable of an adaptive rightward shift in its force-length relationship when it is chronically lengthened by CAPD.

Adaptation, Physiological↗
PubMed1990

Acute renal dysfunction during interleukin-2 treatment: suggestion of an intrinsic renal lesion.

Adoptive immunotherapy with interleukin-2 (IL-2) and lymphokine-activated killer (LAK) cells has been effective in treating some advanced malignancies in animals and humans. One complication of this treatment is a reversible, oliguric, acute renal failure, which has been ascribed to renal hypoperfusion and resultant prerenal azotemia. We serially studied renal function in 10 patients receiving high-dose regimens of recombinant interleukin-2 (rIL-2) to attempt to delineate further the nature of the renal dysfunction caused by IL-2 treatment. Renal plasma flow was computed from iodine 131 (I-131 Hippuran; Mediphysics, Paramus, NJ) orthoiodohippurate, excretion curves, and glomerular filtration rate (GFR) was determined by creatinine clearance. Studies done prior to and on day 4 of treatment showed that GFR fell in nine of 10 patients, with a mean decrease of 43% +/- 8%, and renal plasma flow fell in five of the 10 patients with a mean decrease of 5% +/- 10%. The average pretherapy filtration fraction was calculated to be 23% +/- 1% and after 4 days of treatment, decreased to a mean value of 15 +/- 2%. The BUN to creatinine ratio also declined in all patients. These findings collectively suggest that IL-2 nephrotoxicity may result from an intrarenal defect in addition to the previously described prerenal azotemia. Additionally, radionuclide studies of renal function are a reliable and reproducible noninvasive method of assessing these changes in renal function.

Acute Kidney Injury↗
PubMed1989

Pseudomonal and candidal peritonitis as a complication of continuous ambulatory peritoneal dialysis in human immunodeficiency virus-infected patients.

PURPOSE: To our knowledge, there has been no report documenting the spectrum of peritonitis in human immunodeficiency virus (HIV)-infected persons. We therefore analyzed our records to confirm our previous observation of a higher incidence of pseudomonal and fungal peritonitis in a group of HIV antibody-positive (HIV+) patients undergoing continuous ambulatory peritoneal dialysis (CAPD). PATIENTS AND METHODS: During a 22-month period, we retrospectively studied 71 patients with end-stage renal disease undergoing CAPD. Of these, seven were HIV+, five were at high risk for HIV infection but antibody-negative, and 59 were at low risk for HIV infection. Organisms isolated in episodes of peritonitis were classified microbiologically as one of the following: gram-positive, non-pseudomonal gram-negative, pseudomonal, fungal, or culture-negative. RESULTS: The total peritonitis rate was higher in both the high-risk (p less than or equal to 0.01) and the HIV+ (p less than or equal to 0.02) groups when compared with that in the low-risk population. These differences were attributable to the following: (1) the high-risk group's two-fold increase in gram-positive infections (p less than or equal to 0.01), and (2) a 24-fold increase in pseudomonal (p less than 0.001) infections and seven-fold increase in fungal (p less than 0.005) infections in the HIV+ group. These infections were invariably associated with catheter loss and frequently resulted in conversion to hemodialysis. CONCLUSION: We believe that the use of CAPD in HIV+ patients may be limited by this increased occurrence of pseudomonal and fungal peritonitis.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Acute renal failure associated with ioxaglate, a low-osmolality radiocontrast agent.

Iodinated radiocontrast agents may cause acute renal failure, particularly in patients with preexisting renal failure, heart failure, or diabetes. The low-osmolality contrast agents cause less hypersensitivity, but substantial nephrotoxicity has not been noted. We report three high-risk patients who developed acute renal failure after one of these new agents, ioxaglate, was administered for coronary arteriography and ventriculography. The renal failure was severe: two of the patients required dialysis. We could find no previously reported cases of acute renal failure associated with ioxaglate. Despite their theoretical advantages, the low-osmolality contrast agents may cause acute renal failure in patients who are at risk and should be used with the same precautions as the conventional agents.

Acute Kidney Injury↗
PubMed1989

Survival of human immunodeficiency virus-infected patients on maintenance dialysis.

It has recently been reported that patients on maintenance dialysis with the acquired immune deficiency syndrome (AIDS) survive only 1 to 3 months. We studied all patients on maintenance dialysis at the Baumritter Kidney Center who were known to be infected with the human immunodeficiency virus (HIV). Five patients met the criteria for AIDS; another ten had anti-HIV antibodies but no opportunistic infections. The AIDS patients survived 8 to 18 months, and two are still alive. Mean survival in the AIDS group was 13.2 +/- 1.9 months, while the HIV(+) non-AIDS group survived 15.7 +/- 3.0 months. While these data are not statistically different, the survival curve in the AIDS group predicted a shorter survival than for the HIV(+) patients without AIDS. In fact, the survival of our dialyzed AIDS patients was similar to that reported for AIDS patients in general. Our experience suggests that dialysis may have no adverse effect on survival in AIDS. We conclude that dialysis patients with AIDS may survive 8 to 12 months or more and that the approach to such patients should be individualized.

Acquired Immunodeficiency Syndrome↗
PubMed1988

Determinants of serum creatine kinase activity in dialysis patients.

Elevated creatine kinase (CK) has frequently been described in patients on chronic dialysis, but little is known about its cause and distribution. We, therefore, measured CK in 105 patients on hemodialysis and continuous ambulatory peritoneal dialysis and compared it with biochemical, nutritional, and anthropometric data obtained at the same time. In the entire group, CK was 130.3 +/- (SEM) 15.0 IU/l. Thirty patients had elevated levels of enzyme (greater than 130 IU/l). Isoenzymes determined in patients with elevated CK levels were all more than 97% MM fraction. Men had significantly higher (p less than 0.001) CK values (166.0 +/- 25.8 IU/l) than women (82.4 +/- 9.0 IU/l). Blacks had higher CK values (158.8 +/- 21.7 IU/l; p less than 0.001) than whites (92.6 +/- 12.5 IU/l). Men and blacks had significantly higher weight and midarm muscle circumference than women and whites, respectively. A positive correlation was found between CK and lactic dehydrogenase (p less than 0.001) and between CK and midarm muscle circumference (p less than 0.05), and a negative correlation (p less than 0.01) was found with age. Predialysis and postdialysis CK was measured in 10 patients and did not rise. Three of the patients with elevated CK who have undergone successful renal transplantation showed normalization of CK levels. We conclude that CK is elevated in both hemodialysis and continuous ambulatory peritoneal dialysis patients, particularly in men and blacks, that CK levels are probably related to muscle mass, and that CK declines with advancing age. Although blacks have higher CK values as a whole, normalization of CK values after renal transplantation suggests a contributory role of renal dysfunction.

Adult↗
PubMed1986

Priapism and dialysis.

Ninety-three dialysis units located in the tri-state area were surveyed for the prevalence of priapism. Seventeen of 3,337 male patients experienced an episode of priapism. All of these episodes occurred either during or 2-7 h after dialysis, suggesting a cause-and-effect relationship. The use of heparin during dialysis seemed to play a role in its induction; none of the patients on peritoneal dialysis experienced priapism, and heparin was not used in their exchanges. Eleven of 17 patients also received androgen therapy which might have been a contributing factor. Additional considerations included dialysis-induced hypoxemia and acidosis which have been known to precipitate priapism in patients with sickle cell disease or trait. In our study, 2 of 10 patients, including our case report, were black males with sickle cell trait. The calculated prevalence in the male population is 1:196, and in blacks and Caucasians 1:128 and 1:293, respectively. Except for 2 cases of sickle cell trait in the 10 black males, no particular subpopulation at risk was identified. In view of the absence of a proven etiologic agent and the relatively low prevalence of priapism we do not recommend changes in dialysate, anticoagulant, or the use of androgen therapy.

Adult↗