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Biomedical subjects

C S Marcus

Publications and source records attributed to C S Marcus.

At least 37 records · Page 2Linked to original sources
PubMed1990

Evaluation of children with possible appendicitis using technetium 99m leukocyte scan.

We evaluated the use of technetium 99m albumin colloid white blood cell (TAC-WBC) scan in 33 children with possible appendicitis. Ten children had appendicitis, four of whom had perforated their appendix at the time of surgery. Children with appendicitis differed from children without appendicitis in the incidence of right lower quadrant rebound tenderness (60% vs 17.4%), and white blood cell count (X10(3)/mm3) (14.0 + 1.9 vs 10.7 +/- 1.0). TAC-WBC scans were interpreted as either positive, negative, or indeterminate for appendiceal pathology. Twenty-five children had positive or negative scans for appendiceal pathology. There were 7 true positives, 2 false positives, 16 true negatives, and 0 false negatives. This resulted in a sensitivity of 100%, a specificity of 89%, an accuracy of 92%, a positive predictive value of 78%, and a negative predictive value of 100%. The TAC-WBC scan was indeterminate (abnormal but nondiagnostic for appendicitis) in eight children (24%), three of whom had appendicitis. The main values of TAC-WBC scan in our study of children with possible appendicitis were that it could be used emergently, it was abnormal in 100% of children with appendicitis, and it had a high negative predictive value (100%). The main limitation of TAC-WBC scan in our study was that it was indeterminate for appendiceal pathology in 24% of children. We recommend that TAC-WBC scan be used in children with possible appendicitis because it may allow outpatient management of up to 48%.

Adolescent↗
PubMed1990

Lacrimal gland dosimetry for the brain imaging agent technetium-99m-HMPAO.

We calculated lacrimal gland dosimetry for the brain imaging agent 99mTc-HMPAO. One hundred thirty-eight patients were studied using a dedicated brain imaging device. Only 11% of the patients showed lacrimal gland uptake. For a 740-MBq (20 mCi) injected dose of 99mTc-HMPAO, the radiation exposure to the lacrimal glands is 10.2 mGy (1.02 rad), or 0.0138 mGy/MBq (0.051 rad/mCi). These values are five times lower than the ones reported by the manufacturer of HMPAO. As the dosimetry calculation is only for subjects showing 99mTc-HMPAO uptake in the lacrimal gland, the average radiation dose to all subjects is considerably lower, 1/10 of the estimated value.

Brain↗
PubMed1988

Perioperative suppression of platelet adherence to small-diameter polytetrafluoroethylene (PTFE) grafts.

The perioperative effect of platelet antagonists on small-diameter polytetrafluoroethylene (PTFE) grafts was evaluated in forty-six New Zealand white male rabbits receiving either dipyridamole (DPM) 100 mg/kg/day (n = 10; group 1), aspirin (ASA) 10 mg/kg/day (n = 10; group 2), a combination of ASA 10 mg/kg/day and DPM 10 mg/kg/day (n = 9; group 3) or 100 mg/kg/day (n = 10; group 4), or placebo (n = 7) as single daily doses. All regimens began 72 hr prior to insertion of a 20 x 3-mm internal diameter PTFE interposition aortic graft. Autologous indium-111 labeled platelets were injected immediately after implantation. Graft and an equivalent segment of aorta were harvested after 48 hr. Graft platelet adherence index (GPAI) was calculated as the graft:reference aorta ratio of emissions. The GPAI in the control group was 238 +/- 46 (mean +/- SD). Single regimen antiplatelet agents in groups 1 and 2 reduced mean GPAI to 47 +/- 38 and 40 +/- 12, respectively. The combination regimen in group 3 lowered mean GPAI to 43 +/- 8 and in group 4 to 21 +/- 7. Platelet uptake in PTFE grafts at 48 hr is significantly lowered to 8.8 to 19.7% of control by perioperative antiplatelet agents given as a single daily oral dose (P less than 0.001). ASA alone and DPM alone provided similar suppression of platelet uptake, but combination ASA + low dose or high dose DPM gave significantly greater (P less than 0.001) suppression of early platelet deposition than the single agent regimens. These results support perioperative administration of combination oral antiplatelet agents as adjunctive therapy in small diameter prosthetic graft implantation.

Animals↗
PubMed1988

Phagocytic labeling of leukocytes with 99mTc-albumin colloid for nuclear imaging.

A procedure is described for the phagocytic labeling of white blood cells (WBC) with high specific activity 99mTc--albumin colloid (TAC). The preparation contains approximately equal activities of granulocytes and monocytes. Heparinized whole blood (40 cm3) yields a preparation containing a total of 148-222 MBq (4-6 mCi) TAC-WBC including about 20% free TAC. The complete preparation time is 75 min. Imaging is completed 30 min to 4 h post administration of the TAC-WBC. Quality control methods and imaging protocols are described.

Adult↗
PubMed1988

Appendicitis: evaluation by Tc-99m leukocyte scan.

Diagnosing appendicitis may be difficult. We report the use of a new technetium-99m-albumin colloid white blood cell (TAC-WBC) scan in the evaluation of appendicitis. In a synthesis requiring 75 minutes, autologous neutrophils and macrophages from 40 mL of whole blood were labelled with technetium-99m-albumin colloid and administered to 100 patients with possible appendicitis. The entire process, from labelling the cells to completion of the scan took a maximum of 5 1/4 hours. Two patients had second scans on separate hospitalizations. Twenty-six patients had appendicitis; 12 had perforations, five of whom had an abscess. Eighty-five scans were read as either positive or negative for appendiceal pathology with a sensitivity of 89%, a specificity of 92%, and an accuracy of 92% in diagnosing appendicitis. Seventeen scans were indeterminant; eight of these patients had appendicitis. The value of the TAC-WBC scan in the evaluation of appendicitis lies in its ability to be used emergently, its high negative predictive value for men and women (NPV = 97%), and its high positive predictive value for men (PPV = 93%). At present, the scan does not appear to be reliable in diagnosing appendicitis in women (PPV = 43%). It is most useful in those patients in whom diagnosis is uncertain, and should not be used in patients with clear-cut appendicitis in whom its use will delay definitive surgical care.

Abscess↗
PubMed1988

Unexpected demonstration of superior vena caval obstruction in third trimester lung imaging.

A large focus of liver activity was seen after the injection of Tc-99m macroaggregated albumin (MAA) in a pregnant patient thought to have pulmonary embolism (PE). The correct diagnosis of superior vena caval (SVC) obstruction led to an immediate cesarean section, CT of the chest and abdomen, open lung biopsy of a mediastinal mass, and radiation therapy for the lymphoma with pericardial invasion, all within 24 hours of presentation. The next day, an in vitro labeled Tc-99m red blood cell (RBC) angiogram was performed, which documented collateral flow from the SVC obstruction to the abdomen and filling of the right ventricle via the liver, presumably through reopened channels of the umbilical vein.

Adult↗
PubMed1988

Metastatic papillary thyroid carcinoma with normal serum thyroglobulin level.

Serum thyroglobulin (Tg) levels have proven to be a useful marker for following patients with well differentiated thyroid carcinoma in the evaluation of metastatic disease. This is the report of a case of a patient with papillary thyroid carcinoma and a normal thyroglobulin level despite diffuse lung metastases shown on a total body scan.

Adult↗
PubMed1988

Dosimetry of leukocytes labeled with 99Tcm-albumin colloid.

Biodistribution, kinetics and dosimetry of 9Tcm-albumin colloid labeled leukocytes (TAC-WBC) is described. A practical method of planar image data acquisition and processing is discussed. This method was used to obtain biodistribution data in 11 patients, two of whom were children. Dosimetry was calculated for fetuses, children and adults. The spleen is the critical organ, receiving 2.5 rad per 5 mCi procedure in adults and 3.6 rad per 2.15 mCi procedure in a 5-year-old child. These absorbed doses are about one-sixth of that absorbed from 111In-leukocytes procedures utilizing one-tenth the administered activity of TAC-WBC. The liver and red marrow are approximately equivalent secondary target organs, each receiving about 20% of the spleen dose. Fetal doses at any stage of gestation are similar, averaging about 14 mrad per mCi of TAC-WBC administered to the mother. The dosimetry of TAC-WBC is favorable enough to permit its use in children, adults and during pregnancy.

Adolescent↗
PubMed1988

Radionuclide study of platelets and prosthetic interactions: external versus specimen quantitation.

UNLABELLED: Twenty-nine New Zealand white rabbits were allocated to undergo insertion of either polytetrafluoroethylene (PTFE) (n = 22) or microporous silicone rubber (SR) (n = 7), 3-mm diameter, 10-mm long aortic grafts. Animals with PTFE grafts received aspirin (ASA) 10 mg/kg/d and dipyridamole (DPM) 10 mg/kg/d (n = 11) or placebo (n = 11). Autologous In-111-oxine-labeled platelets were reinfused on reestablishment of blood flow through the graft. Using gamma camera images, an external graft platelet accumulation index (E-GPAI) was calculated as the In-111 activity in the graft area to the reference aorta at 24, 48, and 72 hours post implantation. Mean E-GPAI +/- SEM values for the ASA/DPM (n = 4) and control groups (n = 7) were 1.13 +/- 0.16 and 1.34 +/- 0.05 (NS) at 24 hours, 1.20 +/- 0.16 and 1.33 +/- 0.07 (NS) at 48 hours, and 1.38 +/- 0.07 and 1.35 +/- 0.10 (NS) at 72 hours, respectively. A similar internal graft platelet accumulation index (I-GPAI) was constructed based on In-111 activity in excised grafts and reference aorta measured in a scintillation counter. Mean I-GPAI +/- SEM values for the PTFE ASA/DPM (n = 9) and control groups (n = 8) at 48 hours post implantation were 43.1 +/- 2.7 and 216.8 +/- 73.9 (P = 0.05), respectively. I-GPAI values for the SR grafts were 192.5 +/- 43.1. CONCLUSION: The E-GPAI was not sensitive enough to demonstrate the effect of antiplatelet medication on platelet accumulation on the PTFE grafts.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Comparison of indium 111 oxine-labeled platelet aggregation between sutured and argon laser-assisted vascular anastomoses.

The thrombogenicity of argon laser-assisted vascular anastomoses (LAVAs) was compared with that of sutured vascular anastomoses (SVAs) by measurement of platelet aggregation at the site of repair in a canine model. Sequential 1 cm longitudinal carotid and femoral arteriotomies (n = 80) or jugular and femoral phlebotomies (n = 80) were performed, with each vessel having two tandem, randomly positioned arteriotomies or phlebotomies separated by a 4 cm length of intact vessel. One incision was repaired by SVA with continuous 6-0 polypropylene sutures and the other by argon LAVA. For the laser fusions, argon laser energy was applied to the adventitial surface of the vessel with a 300 micron fiberoptic probe with 0.5 W power, 1100 joules per square centimeter energy fluence, and 150 second exposure per 1 cm length. The arterial and venous segments of SVAs and LAVAs and an equivalent length of normal vessel were harvested at 48 hours (n = 16, 16, 16), 2 weeks (n = 12, 12, 12), and 4 weeks (n = 12, 12, 12). Autologous indium 111 oxine-labeled platelets were injected intravenously 48 hours before removal of the vascular repairs and the radioactivity of the specimens was determined on removal with a NaI (T1) well-type scintillation counter. Anastomotic platelet adherence index (APAI) was calculated as the ratio of emissions of SVA or LAVA to normal reference vessel.(ABSTRACT TRUNCATED AT 250 WORDS)

Anastomosis, Surgical↗
PubMed1987

Evaluation of Tc-99m leukocyte scan in the diagnosis of acute appendicitis.

A new 99mTc Microlite leukocyte scan was performed in 38 patients to assess its value in the diagnosis of acute appendicitis. Autologous leukocytes are labeled with 99mTc by inducing phagocytosis of 99mTc albumin microcolloid particles. The advantages of this test over the standard indium-111 scan include superior imaging capability, a marked reduction (greater than 75%) in the radiation dose, and performance of the test including labeling, in less than 3 hr. Imaging is performed at 5-90 min postinjection of labeled cells. There were 19 male and 19 female patients with ages ranging from 10 to 80 years, in whom the diagnosis of appendicitis was indeterminate on clinical examination. Of the 13 of the 38 patients (34%) who came to surgery 12 had acute appendicitis. The WBC scan correctly identified 10 of the 12 cases of appendicitis. There were two false-negative studies. In the nonoperative group of 25 patients admitted for observation, 21 studies were reported as negative and four identified other sites of inflammation. All patients with a negative study have remained asymptomatic on follow-up. With a sensitivity of 83% (10/12) and a specificity of 100% (26/26) the 99mTc leukocyte scan provides a rapid and highly accurate method for diagnosis of appendicitis in this preliminary study of patients with equivocal clinical exams.

Acute Disease↗
PubMed1987

Survival of red cells stored for 21 and 35 days in a non-di-(2-ethylhexyl)phthalate plastic container.

Whole blood and red cells were stored using citrate-phosphate-dextrose (CPD) and citrate-phosphate-dextrose-adenine (CPDA-1) anticoagulants in polyvinylchloride bags made flexible with di-(2-ethylhexyl)phthalate (DEHP) or tri-(2-ethylhexyl)trimellitate (TOTM) plasticizers. After storage the posttransfusion viability of these cells was tested in autologous donors. Cells stored in TOTM-plasticized film had a survival rate less than 75% when stored for 35 days, while other systems had a survival greater than this. When compared with the red cells stored in CPD-DEHP-plasticized film, the viability of whole blood and red cells stored in CPDA-TOTM showed a statistically significant decrease (p = less than 0.01). Therefore, red cell storage in TOTM-plasticized PVC with current anticoagulant should be limited to 21 days.

Benzoates↗
PubMed1986

Evaluation of the utility of indium-111 oxine platelet imaging in renal transplant patients on cyclosporine.

Twenty five In-111 oxine platelet imaging procedures were performed in 21 renal transplant patients to assess the value of this study for diagnosis of renal transplant rejection in recipients receiving cyclosporine (CYS) for immunosuppression. Fourteen biopsies were performed, and an extensive, in-depth review of the clinical progress of each patient was obtained. There was no ideal "gold standard" to which our imaging results could be compared, but we used a combination of biopsy findings, clinical impressions, and changes in renal function after pulsing with steroids and/or decreasing CYS dosage as the basis for our diagnoses. We were unable to distinguish between renal rejection and CYS toxicity using platelet imaging. The sensitivity of the platelet procedure for diagnosing rejection or CYS toxicity was 100%. The specificity for rejection or CYS toxicity was only 76.5%. In view of the inability of this test to distinguish between rejection and CYS toxicity, its rather low specificity, and its relatively high cost, it is not a particularly helpful study for the diagnosis of renal transplant rejection in patients on CYS.

Blood Platelets↗
PubMed1986

Use of factor analysis in the evaluation of left to right cardiac shunts.

We have compared two methods of data processing for the quantitation of left-to-right cardiac shunts using first-pass radionuclide angiography. These two methods are used for curve generation in the deconvolution analysis. The standard method involves manual definition of regions of interest. A newer method--factor analysis--provides automatic curve generation and is therefore more operator-independent. Both techniques yield curves of the venous input, lung, and background. The venous input curve is deconvolved by the lung curve, and the resultant unit impulse response is fitted by the gamma variate method to quantitate the left-to-right shunt fraction. Both techniques--factor analysis and regions of interest (ROIs)--separated the shunt patients (n = 16) from the control subjects (n = 20) with a p less than 0.001. There was less interobserver variability with the curves obtained by factor analysis than with those obtained by regions of interest. The coefficient of correlation of factor analysis results with oximetry, r, was 0.90. High sensitivity and specificity, each 94%, was achieved with curves generated by factor analysis. Time vs. activity curves generated by ROIs can achieve high sensitivity and low specificity, or vice versa, depending on the cutoff level defined for separation of the left-to-right shunt patients from the control group.

Adult↗