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Biomedical subjects

E R Reinitz

Publications and source records attributed to E R Reinitz.

At least 19 recordsLinked to original sources
PubMed1990

Prospective peritoneal scintigraphy in patients beginning continuous ambulatory peritoneal dialysis.

Forty-eight adult patients without clinical evidence of inguinal or abdominal wall hernias underwent peritoneal scintigraphy shortly after beginning continuous ambulatory peritoneal dialysis (CAPD). Scintigraphically detectable subclinical structural defects involving the inguinal canal or abdominal wall were present in 14 patients. Within 5 months, four of these defects progressed to clinically significant CAPD-related structural complications. These patients could not be distinguished by clinical or scintigraphic criteria from the 10 patients with nonprogressive structural defects. No scintigraphic structural defects were detected in 34 patients, 30 of whom remained free of CAPD-related structural complications. Five patients developed symptomatic structural complications during follow-up in areas that had been scintigraphically normal at the onset of CAPD. We conclude that some CAPD-related structural complications arise de novo, while others represent progression of subclinical pre-existent structural abnormalities that can be detected by peritoneal scintigraphy. However, most asymptomatic scintigraphic defects do not progress to a symptomatic stage, limiting the usefulness of prospective peritoneal scintigraphy as a guide to recommend prophylactic repair of all asymptomatic structural defects in patients beginning CAPD.

Adult↗
PubMed1990

Does the end-to-end venous anastomosis offer a functional advantage over the end-to-side venous anastomosis in high-output arteriovenous grafts?

This study explores the hemodynamics, mechanics, and biologic response of end-to-end versus end-to-side venous anastomoses in a canine arteriovenous graft model. Femoral polytetrafluoroethylene grafts were implanted bilaterally in a paired fashion (n = 22). Detailed local hemodynamic measurements were made by use of color Doppler ultrasound imaging at 1, 4, 8, and 12 weeks after implant. Measurements included volumetric flow rate and Doppler-derived spectral window (percent window) as a measure of turbulence. Amplitude and velocity of vessel wall movement were also measured. Volume of perivascular tissue vibration quantitated kinetic energy transfer through the vessel wall. Volumetric flow rate (end to end, 1013 +/- 70 ml/min; end to side, 1015 +/- 72 ml/min), percent window (end to end, 6.6% +/- 0.6%, end to side, 5.6% +/- 0.4%) and volume of perivascular tissue vibration (end to end, 19.6 +/- 1.2 ml, end to side, 16.3 +/- 1.8 ml) were statistically equivalent in the two graft types (end to end vs end to side p greater than 0.05). Both graft types developed venous intimal-medial thickening of a similar magnitude: end to end, 0.35 +/- 0.05 mm, end to side, 0.43 +/- 0.09 mm, normal vein 0.070 +/- 0.004 mm (analysis of variance [ANOVA] p less than 0.001, p less than 0.01 for end to end or end to side vs control, end to end vs end to side p greater than 0.05 by Student-Newman-Keuls test). The best correlations with venous intimal-medial thickening were obtained from inverse percent window (r = 0.84, p less than 0.001) and volume of perivascular tissue vibration (r = 0.68, p less than 0.001). In the end to end configuration the relative amplitude of venous wall movement decreased, and the relative velocity of wall motion increased over time. We conclude that in the circumstances of this high flow arteriovenous graft model the end-to-end venous anastomosis does not significantly differ from the end-to-side venous anastomosis in terms of flow stability, turbulence, or kinetic energy transfer. The magnitude of the hyperplastic response is statistically equivalent for the two anastomotic types, but the pattern is somewhat different, possibly providing evidence for differences in stress distribution. Differences in the relative amplitude and velocity of vessel wall movement suggest that anastomotic geometry may affect the way in which kinetic energy is dissipated at the graft/vessel interface.

Animals↗
PubMed1990

Graft geometry and venous intimal-medial hyperplasia in arteriovenous loop grafts.

This study explores graft geometry and hemodynamics in a reproducible canine arteriovenous loop graft model of intimal-medial hyperplasia. Untapered 6 mm diameter polytetrafluoroethylene grafts (n = 10) were paired with 4 to 7 mm taper (n = 5) or 7 to 4 mm taper (n = 5) grafts for a 12-week period. Several hemodynamic variables were assessed at multiple locations, and venous intimal-medial thickness was measured at locations corresponding to the hemodynamic measurements. Color Doppler imaging demonstrated energy transfer out of the vessel in the form of perivascular tissue vibration. This was quantitated by the distance required for Doppler signal attenuation or volume of the detected vibration signal. Differences among graft types were noted for pressure, flow velocity, tissue vibration, and venous intimal-medial thickness. Hyperplasia was significantly decreased in 4 to 7 mm taper grafts. Stepwise deletion regression indicated volume of the vibration signal had a better correlation with venous intimal-medial thickness than any other variable (r 0.9, p less than 0.001). We conclude that graft geometry can have a significant impact on hemodynamic factors and venous intimal-medial hyperplasia in arteriovenous loop grafts. Flow disturbances appear to cause energy transfer through the vessel wall and into perivascular tissue. Kinetic energy transfer in the form of perivascular tissue vibration was quantitated in vivo and correlates strongly with venous intimal-medial thickness.

Animals↗
PubMed1989

Detection of cytomegalovirus-specific IGM in renal transplant recipients.

We have compared two IgM-specific cytomegalovirus (CMV) antibody assays, an immunofluorescence assay (IFA-M) and an enzyme-linked antigen immunoassay (ELA-M), with an assay for CMV total antibody (ELISA) and viral culture for the detection of active CMV infection in renal transplant recipients. Of 75 patients (49 ELISA negative pretransplant, 26 ELISA positive), CMV-specific IgM was detected in 35 (27 ELISA negative pretransplant, 8 ELISA positive) using the IFA-M assay and in 25 (16 ELISA negative pretransplant, 9 ELISA positive) using the ELA-M test. Of the 25 patients identified as positive by ELA-M, 21 had positive viral cultures post-transplant, two seronegative patients had evidence of infection indicated by post-transplant seroconversion, and two patients were seropositive pretransplant but remained viral culture negative throughout the follow-up period. ELA-M and CMV total antibody ELISA detected primary infection in renal transplant recipients equally well, but ELA-M was found to be superior to ELISA and IFA-M for detecting reinfection and reactivation infections.

Antibodies, Viral↗
PubMed1989

Beneficial effects of banding on venous intimal-medial hyperplasia in arteriovenous loop grafts.

Local hemodynamics were modified in a canine arteriovenous loop graft model by placing a flow-limiting band on femoral polytetrafluoroethylene (PTFE) grafts. Banded and unbanded grafts were implanted in a paired fashion. Hemodynamic studies included Reynolds number and phonoangiography as measures of turbulence. Intimal-medial thickness was measured 8 weeks after implantation. Reduction of the volumetric flow rate by 50 percent resulted in significant changes in flow velocity, flow pulsatility, pressure, and turbulence at the venous anastomosis. Hyperplastic lesions developed in a reproducible manner at the venous anastomosis of the unbanded but not the banded grafts, as evidenced by combined intimal-medial thickness measurements: unbanded grafts 0.68 +/- 0.13 mm (p less than 0.01 versus control), banded grafts 0.25 +/- 0.03 mm (p greater than 0.05 versus control). Stepwise regression analysis indicated Reynolds number had the best correlation with the development of hyperplasia (r = 0.915, p less than 0.005), this being the first time this correlation has been quantitatively determined. We conclude that flow disturbance or turbulence is a major factor in the development of venous intimal-medial hyperplasia in arteriovenous loop grafts.

Animals↗
PubMed1989

Posterolateral exposure for renal artery reconstruction.

Anterior approaches to the renal arteries are complicated by the intervening renal veins, inferior vena cava, and abdominal viscera. We describe techniques of direct posterolateral access to both right and left renal arteries by use of an extended retroperitoneal exposure. This approach allows for grafting from the aorta or iliac artery on either side and is particularly suitable on the left side for direct retropancreatic splenorenal artery anastomosis, which is described in detail. It is also useful for distal reconstruction of branch renal arteries, renal artery embolectomy, and autotransplantation "bench surgery." We have used this approach in 28 patients with no operative deaths and two reconstructive occlusions.

Humans↗
PubMed1989

Isolation and preliminary characterization of immunoinhibitory factors from dog erythrocytes and liver.

Crude dog liver extract (DLE) inhibits proliferation of dog and human lymphocytes stimulated by phytohemagglutinin and alloantigens. While purifying this activity from dog liver, we observed that dog liver inhibitory factor (DLIF) shared properties with hemoglobin. DLIF migrated with hemoglobin during DEAE cellulose chromatography, and DLIF had oligomeric (61,900) and subunit (17,900 and 15,700) apparent molecular weights (AMW) similar to concurrently analyzed Sigma canine hemoglobin (61,100, 16,700 and 14,900). After separate cross linking, the proteins comigrated on sodium dodecyl sulfate (SDS) polyacrylamide gel electrophoresis (PAGE) gels. We therefore isolated dog erythrocyte inhibitory factor (DEIF) from red blood cells to determine if DEIF was a hemoglobin derivative. DEIF, like DLIF, separated at an isoelectric point of 5.6. DEIF also had similar subunit AMW (17,600 and 15,300) by SDS PAGE, but DEIF had much lower lymphocyte inhibitory activity (LIA = 2.27) than DLIF (LIA = 100.00). We conclude that DLIF and DEIF are similar to each other and hemoglobin, but further studies are needed to determine the function and exact structure of DLIF and DEIF.

Animals↗
PubMed1989

Natural killer cell activity in rats infused with Intralipid.

The effect of Intralipid on the natural killer (NK) cell activity of healthy male Fisher 344 adult rats was investigated. They were cannulated via the right jugular vein and continuously infused for five days with: normal saline plus heparin, 5% Intralipid plus heparin, or 10% Intralipid plus heparin. Control groups comprised of cannulated rats receiving no infusion and rats undergoing no operative procedures. Following the five-day infusion, rats were exsanguinated under ether anesthesia and mononuclear cells (MNC) harvested from the peripheral blood. NK activity was measured in a standard four hour 51Cr release assay against YAC-1 target cells. NK cell activity in rats infused with 5% Intralipid did not differ significantly from rats in both control groups or rats infused with saline. Infusion of rats with 10% Intralipid resulted in a significant increase in NK activity compared with all other groups.

Animals↗
PubMed1988

Variation in indirect cell-mediated lympholysis.

The ability of an allograft recipient to respond to donor mononuclear cells in an indirect cell-mediated lympholysis (ICML) assay is an in vitro correlate of allograft rejection, but the value of this correlation depends upon the assay's reliability. We had observed inconsistency in the cytotoxic response of normal human mononuclear cells (MNC) to the same allogeneic stimulator MNC when cytotoxicity was measured repeatedly on different occasions by micro-ICML. We, therefore, investigated the extent and reasons for this inconsistency. Method variation, determined by duplicate ICML of 18 stimulator: responder MNC, was not statistically significant. Variation in cytotoxicity over time was greater but still not statistically significant. The contribution to method variation of 51Cr release from 3 different sets of target cells, cultured and labeled in duplicate, was minimal (6.33%). We then asked if in vitro generation of effector MNC under laboratory conditions was a major cause of ICML variation. We tested this using a stable transplant's in vivo sensitized effector cells against donor MNC in a direct CML (DCML) and obtained consistent results. Finally, to gain an understanding of some of the factors which might influence the generation of in vitro cytotoxicity, we measured the frequencies of cell surface antigens (DR, TAC, transferrin, Leu 2 and 3) concomitantly with ICML on day 6 of culture. Statistical analysis of the results led us to conclude that the micro-ICML is reproducible. The magnitude of lysis depends upon activated target cells (TAC- and transferrin-positive) and an increase in the proportion of helper/inducer to cytotoxic/suppressor T-lymphocytes during effector cell generation.

Antigens, Surface↗
PubMed1984

Saralasin acetate test in renal transplant hypertension. Report of 17 cases and a review of the literature.

The saralasin acetate test was performed in 17 hypertensive patients with renal transplants. These results were compared with 39 previously published reports of transplant patients who had been tested in the same manner. Eighty-two percent of our patients had a positive saralasin acetate test, suggesting renin-dependent hypertension. Baseline plasma renin activity (PRA) was significantly higher in patients with positive tests (6.96 +/- 1.75 v 2.88 +/- 0.53 ng/mL/hr). However, positive tests were obtained in several patients who had normoreninemia, and PRA levels did not correlate with the magnitude of vasodepressor BP response to saralasin. Transplant artery stenosis, acute rejection, and chronic rejection were the most common posttransplant complications associated with a positive test, but several patients had hypertension alone. While highly sensitive for renin-dependent hypertension posttransplantation, the test had poor specificity for identification of any one cause of posttransplant hypertension.

Blood Pressure↗
PubMed1984

Non-renin dependent hypertension in renal allograft rejections. A structural and functional analysis.

A 25-year-old recipient of a cadaveric renal allograft underwent three acute rejection episodes within the first 40 days after transplant, the final episode necessitating nephrectomy. The saralasin acetate infusion test and plasma renin activity (as measured by radioimmunoassay of angiotensin I) were used as functional tests of the renin-angiotensin axis. Biopsy specimens of the allograft one hour after implantation and sections of the nephrectomy specimen were fixed and stained with hematoxylin-eosin for structural analysis. On three separate dates, during the final rejection episode, saralasin acetate infusion of up to 20 micrograms/kg/min failed to lower BP significantly. The final two trials were preceded by furosemide administration the previous day to reduce fluid volume. Plasma renin activity was low on all three dates. On nephrectomy, the allograft was noted grossly to be infarcted. Histologic examination revealed cortical necrosis, markedly narrowed or occluded intrarenal vessels, and extremely narrowed large vessels within the renal pelvis. The allograft renal artery was thickened and narrowed. From our structural and functional analysis we conclude that (1) hypertension, in this case, was probably volume dependent and was clearly renin independent; and (2) the low renin levels are explainable on the basis of extensive vascular occlusion producing renal infarction and resulting in a kidney incapable of producing significant amounts of renin (autonephrectomy).

Adult↗