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PubMedDate not supplied

The use of exercise technetium-99m 2-methoxy-isobutyl-isonitrile (99mTc-Sestamibi) perfusion scanning in the detection of acute rejection after cardiac transplantation.

Acute cardiac rejection remains an important cause of death during the first year following cardiac transplantation. Right ventricular biopsies at regular intervals are the main method of detecting rejection, although it is invasive. Unfortunately, non-invasive methods of detecting rejection have not proved reliable enough to replace cardiac biopsies. We assessed the usefulness of technetium-99m 2-methoxy-isobutyl-isonitrile (99mTc-Sestamibi) perfusion scanning in detecting acute rejection in 12 human orthotopic cardiac transplant recipients. Rest and exercise studies and right ventricular biopsies were performed on two occasions. Isotopic evidence of rejection was defined as a perfusion abnormality on either the resting or exercise studies. 99mTc-Sestamibi studies successfully identified acute rejection in 8 of 11 rejection episodes (p less than 0.04). The calculated sensitivity and specificity of 99mTc-Sestamibi scanning were both 72%. Perfusion scanning with 99mTc-Sestamibi may be useful in the diagnosis of acute rejection in cardiac transplant recipients.

Adult↗
PubMedDate not supplied

Conditions for labeling of Schistosoma mansoni cercaria with technetium-99m.

Study of the labeling of Schistosoma mansoni cercaria with technetium-99m (99mTc) at room temperature (25 degrees C) and 37 degrees C shows that the incorporation of radioactivity in this cercaria increases with the increase in stannous chloride concentration, reaching a constant value threshold at 130.00 microM. Strong binding of the 99mTc was obtained since the radioactivity was not washed out. The characteristic motion of the cercaria, labeled at 25 degrees C and 37 degrees C, was only modified at the concentration of 1300 microM for both temperatures, showing that the methodology here described can be applied to living structures. With this technique it is possible to obtain a cercariae suspension labeled with a radionuclide that is very inexpensive and readily available. Furthermore, it is a gamma emitter with a photon energy of 140 keV that would permit one to make scannings of the infected animals and causes less of an environmental impact and present fewer radioactive disposal problems than the long lived radionuclides.

Animals↗
PubMed1992

Prospective evaluation of the efficacy of technetium 99m sestamibi and iodine 123 radionuclide imaging of abnormal parathyroid glands.

BACKGROUND: Technetium 99m sestamibi is an isonitrile radionuclide imaging agent that, when used with subtraction iodine 123 thyroid scans, has the potential for imaging abnormal parathyroid glands. METHODS: We prospectively evaluated 20 patients with hyperparathyroidism to study the efficacy of Tc 99m sestamibi and 123I subtraction radionuclide scanning for the imaging of abnormal parathyroid glands. All patients underwent neck exploration and histologic confirmation of all parathyroid glands identified. RESULTS: The solitary adenomas in 11 of 16 patients with primary hyperparathyroidism were localized with sestamibi scans. The scans in four of five patients with diffuse parathyroid hyperplasia showed bilateral localization consistent with enlarged glands. The fifth patient previously underwent a subtotal parathyroidectomy, and a fifth supernumerary gland was localized with the sestamibi scan. Four patients had hyperparathyroidism related to kidney disease. Three of these had bilateral localization of enlarged glands. The fourth patient had undergone two previous operations, and a fifth supernumerary gland was localized with the sestamibi scan. CONCLUSIONS: The preliminary data indicate that Tc 99m sestamibi in combination with 123I radionuclide scanning may be useful in the preoperative localization of abnormal parathyroid glands. This technique localized all of the solitary adenomas that were subsequently resected, and in two reoperative cases it identified the remaining solitary gland causing persistent hypercalcemia.

Adult↗
PubMed1992

Detection of acute appendicitis by technetium 99 HMPAO scanning.

The diagnosis of acute appendicitis can be difficult. Barium enemas, computed tomography (CT) scans, ultrasound examinations and Indium scans are used to aid in making the diagnosis with varying degrees of success. This blinded, prospective study reports the use of a Technetium 99-m Hexamethylpropyleneamineoxide (HMPAO) labelled white blood cell scan in 30 patients with suspected appendicitis. Autologous white blood counts from 25 cc of whole blood labelled with Tc-99 HMPAO were reinjected into patients. Abdominal imaging was performed at a half hour postinjection and repeated at 2 to 4 hours postinjection. A positive study showed an increased isotope uptake in the right lower quadrant. Nineteen patients had histologically proven appendicitis. Three of these patients were excluded because they were operated on before scan completion. Thirteen of the remaining 16 patients with appendicitis had positive studies (false negative rate = 19%). All patients without appendicitis had either negative scans or scans that detected other intra-abdominal diseases, such as diverticulitis, tubo-ovarian abscess, or small bowel infarction (false positive rate = 0%). Overall, this Tc-99 HMPAO study had a sensitivity of 81 per cent, a specificity of 100 per cent and an overall accuracy of 89 per cent. The 4-hour Tc-99 HMPAO WBC scan is a useful, noninvasive test for confirming the clinical diagnosis of acute appendicitis, but it may prove more valuable as a diagnostic study to rule out appendicitis in patients that have abdominal pain of unclear etiology.

Acute Disease↗
PubMedDate not supplied

Comparison of FDG-PET and technetium-99m MIBI SPECT to detect metastatic cervical lymph nodes in well-differentiated thyroid carcinoma with elevated serum HTG but negative I-131 whole body scan.

The aim of this study was to evaluate the usefulness of 18-fluoro-2-deoxyglucose (FDG) positron emission tomography (PET) and technetium-99m methoxyisobutylisonitrile (Tc-99m MIBI) single photon emission computed tomography (SPECT) in detecting metastatic cervical lymph nodes (LN) in well-differentiated thyroid carcinoma (DTC) after total thyroidectomy and radioiodine-131 (I-131) treatments in patients with elevated serum human thyroglobulin (hTg) levels but negative I-131 whole body scan (WBS). Fifteen DTC patients underwent nearly total thyroidectomy and I-131 treatments with cervical LN metastases were included in this study. All subjects had negative I-131 WBS and elevated hTg levels (hTg > or = 10 microIU/ml) under thyroid-stimulating hormone (TSH) stimulation (TSH > or = 30 microIU/ml). FDG-PET could detect all of the 15 (100%) patients with metastatic cervical LN, but Tc-99m MIBI SPECT revealed lesions in only 9 out of 15 (60%) patients (p value < 0.05). This study demonstrated that FDG-PET is more sensitive than Tc-99m MIBI SPECT in detecting metastatic cervical LN in DTC with elevated serum hTg levels but negative I-131 WBS.

Adult↗
PubMed2004

Correlation between myocardial uptake of technetium-99m-sestamibi and pressure-derived myocardial fractional flow reserve.

OBJECTIVES: Development of the coronary pressure wire has facilitated the measurement of fractional flow reserve (FFR) to assess the functional severity of coronary artery stenoses. METHODS: This study evaluated the correlations between FFR and myocardial direct counts of technetium-99m(99mTc)-sestamibi in 20 patients (16 men, 4 women, mean age 66 +/- 8 years) who underwent 99mTc-sestamibi single-photon emission computed tomography (SPECT) with the 2-day protocol using 740 MBq of 99mTc-sestamibi each day. Visual assessment of myocardial imaging and quantitative analysis with the measurement of percent uptake and direct count of 99mTc-sestamibi were performed. RESULTS: Visual assessment of myocardial imaging revealed that reversibility of 99mTc-sestamibi perfusion defects was correlated with FFR of < 0.75, which is regarded as functionally important stenosis (17/20 vs 3/20, kappa = 0.71, p < 0.002). Regional reversibility score did not correlate with FFR (r = -0.40, p = NS). Quantitative analysis revealed that the change in 99mTc-sestamibi percent uptake with pharmacologic stress using adenosine triphosphate disodium (ATP) also did not correlate with FFR (r = 0.35, p = NS). In contrast, percent increase in 99mTc direct counts with ATP was lower in patients with FFR of < 0.75 than in those with FFR of > = 0.75 (-4 +/- 16% vs 24 +/- 30%, p < 0.01). In addition, a significant correlation (r = 0.70, p < 0.001) was observed between percent increase in 99mTc direct counts with ATP and FFR. CONCLUSIONS: These results suggest that quantitative analysis of 99mTc-sestamibi scintigraphy enables the assessment of the magnitude of functional significance of coronary stenosis.

Adenosine Triphosphate↗
PubMed1992

Comparison of same-day protocols using technetium-99m-sestamibi myocardial imaging.

Two same-day protocols (rest/exercise [Protocol 1] and exercise/rest [Protocol 2]) with sestamibi (hexakis 2-methoxy-2-isobutyl-isonitrile) were performed within 2 to 14 days of each other after randomization. The initial study in each protocol was done using a dose of 185-296 MBq of 99mTc-sestamibi. The second study in each protocol used a dose of 555-925 MBq. SPECT imaging was started 30 to 60 min after injection using a 180 degrees anterior arc. Segmental analysis was interpreted as normal, scar or ischemia (20 segments/patient). Among the protocols, there was concordance in 93% of the segments (593/640 segments). In the 11 patients with coronary artery disease and no prior myocardial infarction who had ischemic abnormality, count densities from abnormal and normal zones were compared between the two protocols. Protocol 1 showed greater count differences between abnormal and normal zones on exercise images with better normalization of abnormality on rest images than Protocol 2 (p less than 0.05). Technetium-99m-sestamibi provides high quality images using either of the two same-day protocols. However, the rest/exercise protocol provides better image contrast and ability to detect reversibility of perfusion defects, and is the preferred same-day protocol.

Ambulatory Care↗
PubMed1992

Parathyroid imaging with technetium-99m-sestamibi: preoperative localization and tissue uptake studies.

The accepted radionuclide method for imaging abnormal parathyroid tissue has been the combined use of [99mTc]pertechnetate 201Tl-chloride. Various problems with this approach, however, have suggested the need for an improved parathyroid imaging agent. This study examined the use of 99mTc-sestamibi as a parathyroid imaging agent compared with 201Tl-chloride. Fifty-seven patients were scanned with both 99mTc-sestamibi and 201Tl preoperatively. There were 40 adenomas, of which 37 were localized with 201Tl and 39 with sestamibi. Fifteen patients had hyperplastic glands, of which 29 glands were localized with 201Tl and 32 with sestamibi. Possible differences in uptake of the two agents by thyroid and parathyroid tissue were examined by administering 10 MBq of each agent to patients undergoing surgical exploration and biopsy. Preoperatively 20 patients were studied (13 adenomas and 7 with hyperplasia). Thallium-201 uptake was higher in both the parathyroid and thyroid tissue than sestamibi. However, the uptake per gram of parathyroid tissue of sestamibi was higher than the uptake per gram of thyroid tissue. This was not true for 201Tl. Technetium-99m-sestamibi was at least as effective as 201Tl in parathyroid localization. This may be partly due to a higher target-to-background ratio, but also to the superior physical characteristics of 99mTc.

Adenoma↗
PubMed2004

Chemical and biological evaluation of technetium (I) tricarbonyl complexes with EHIDA and DPD. 99m (I) complexes of EHIDA and DPD.

BACKGROUND: 99mTc-phosphate and 99mTc-IDA complexes, made by the addition of 99mTcO4- to the kits, have been applied to bone and gallbladder imaging respectively, for many years. In this paper, an effort to label DPD and EHIDA with [99mTc(CO)3(H2O)3]+ was carried out. MATERIAL AND METHODS: DPD and EHIDA were synthesised and prepared in kit form in INS "Vinca". A carbonyl labelling agent Isolink (Mallinckrodt Medical B.V.) and a carbonyl precursor (NCRS Demokritos) were applied. The samples of each compound were added to a vial containing 99mTc-carbonyl precursor, in which original pH (10/11) was neutralised to a pH of around 5.5 or 7.5, the same one as the pH of the investigated compounds. After heating, the reaction products were analysed by HPLC equipped with UV and g-detector, with TEAP 0.05 M, methanol and water as solvent. The biological evaluation of 99m99mTc(I)-coordinated compounds, as well as 99mTc-DPD and 99mTc-EHIDA complexes, involved a bio distribution examination on Wistar rats. RESULTS: The results have shown that hydrophilic organometallic [99mTc(CO)3(H2O)3]+ precursor facilitates the formation of Tc (I) complexes with these ligands, based on the tricarbonyltechnetium (I) core. The changes in structure of DPD and EHIDA labelled molecules influenced biological behaviour: 99Tc(CO)3 -DPD did not accumulate in bone (< 1% of the complex was found in the femur), while 99Tc(CO)3-EHIDA has shown slower billiary excretion and faster filtration through the kidneys. DISCUSSION: The results of the labelling of DPD and EHIDA with [99mTc(CO)3(H2O)3]+ and their chemical and biological behaviour, in comparison with the same one for 99mTc-DPD and 99mTc-EHIDA, confirmed that different oxidation states of technetium make the formation of a variety of complexes with quite different behaviour possible.

Animals↗
PubMed2004

Measurement of renal function by calculation of fractional uptake of technetium-99m dimercaptosuccinic acid.

BACKGROUND: The purpose of this study was to set up normal values of the fractional uptake (FU) of technetium-99m dimercaptosuccinic acid in adults and in the pediatric population, as well as to evaluate the validity of this parameter at different levels of renal function. MATERIAL AND METHODS: A total of 86 subjects was divided into seven groups. In group A there were 23 potential kidney donors and in group B, 18 children in remission after a first urinary tract infection. Another three groups consisted of patients with diabetes i.e. group C, seven patients with normal values of albuminuria, group D, 16 patients with microalbuminuria and group E, five patients with macroalbuminuria. In group F, there were ten patients with a well-functioning transplanted kidney and in group G, seven patients with suspected acute rejection. The procedure began with the quantification of the doses of 99mTc-DMSA to be injected and the measurement of the empty syringe lying on the gamma camera collimator. Thereafter, four planar views of the kidneys were acquired three hours after the injection. The counts from the posterior and anterior views were subtracted for background and corrected for radioactive decay time and patient thickness. The FU was calculated by the geometric mean of counts per second from the posterior and anterior view. It was expressed as a fraction of the injected dose. RESULTS: The mean values of FU in healthy adults were 0.227 +/- 0.077 for one kidney and 0.454 +/- 0.146 for both kidneys. The mean values of FU for the left and right kidney were 0.225 +/- +/- 0.071 and 0.229 +/- 0.079, respectively. In children, the mean values were 0.220 +/- 0.092 for one kidney and 0.432 +/- 0.094 for both kidneys. The highest values of FU of 0.322 +/- 0.078 (0.644 +/- 0.138 for both kidneys) were measured in group C. In group D, FU was 0.185 +/- 0.065 (0.361 +/- 0.125 for both kidneys) and in group E 0.082 +/- 0.040 (0.163 +/- 0.080 total). In patients with a transplanted kidney, fractional uptake was 0.162 +/- +/- 0.039 in group F and 0.065 +/- 0.021 in group G. There was no significant difference in the values of FU between healthy adults and children. The uptake in group C was 41% higher than in group A and the difference was statistically significant. In groups D and E, the uptake was significantly lower than in A. In both groups of patients with transplanted kidneys, the uptake was significantly lower than in control group. The correlation between FU and biochemical parameters of renal function [blood urea nitrogen (BUN), serum creatinine (Cr) and creatinine clearance (CCr)] was significant: FU/BUN r = -0.86; FU/Cr r = -0.77; FU/CCr r = 0.60. CONCLUSION: Fractional uptake of 99mTc-DMSA could serve as a sensitive parameter of renal function. The mean values of FU in adults were 0.454 and in children 0.432. There was no significant difference between values for the left and right kidney. In diabetes mellitus, fractional uptake correlated well with the degree of diabetic nephropathy. In patients with a well-functioning transplant, the uptake was slightly reduced. Low values of fractional uptake in acute rejection were related to lesions in kidney blood vessels and in tubular cells.

Adult↗
PubMed2004

Predicting the effect of intravenous calcitriol on parathyroid gland activity using double-phase technetium Tc 99m-sestamibi scintigraphy.

BACKGROUND: Although intravenous calcitriol is useful for decreasing intact parathyroid hormone (iPTH) blood levels in patients with secondary hyperparathyroidism (SHP) undergoing hemodialysis, approximately half these patients remain refractory to this treatment. The current study measures the diagnostic utility of double-phase technetium Tc 99m-sestamibi (MIBI) scintigraphy in predicting the response to calcitriol treatment. METHODS: Sixty hemodialysis patients with SHP with iPTH blood levels between 240 and 600 pg/mL (ng/L) were selected. Initial intravenous calcitriol pulse therapy was 6 microg/wk (for iPTH levels of 400 to 600 pg/mL [ng/L]) or 3 microg/wk (for iPTH levels of 240 to 400 pg/mL [ng/L]). MIBI scintigraphy was performed before the onset of calcitriol therapy and repeated 1 year later. Patients were injected intravenously with 740 MBq of MIBI. Images were obtained at 15 minutes (thyroid phase) and 2 hours (parathyroid phase) after radiotracer administration. Focal areas of increased MIBI uptake were considered pathological parathyroid glands. RESULTS: Forty-eight patients completed the study. After 1 year, iPTH levels had decreased significantly in 95.2% (47 patients), whereas good control (iPTH < 240 pg/mL [ng/L]) was reached in 70.8% (34 patients) and only 4 patients had iPTH levels greater than 400 pg/mL (ng/L; all were patients with 3 MIBI-positive areas at baseline determination). At baseline, there were 30 patients (62.5%) with MIBI positive areas (1, 2, or 3 areas), which decreased to 14 patients (29%) at the end of the study period. No patient showed 4 positive areas at any time. The 18 patients (37.5%) with no MIBI-positive area at baseline remained unchanged. CONCLUSION: MIBI scintigraphy is a reliable exploratory tool in predicting the response to treatment with intravenous calcitriol in hemodialysis patients with SHP.

Adult↗
PubMedDate not supplied

[Myocardial scintigraphy with technetium 99m methoxyisobutylisonitrile. A comparison with coronary arteriography in patients with suspected ischemic cardiopathy].

Technetium-99m methoxy-isobutyl-isonitrile (MIBI) myocardial scintigraphy has been proposed as an alternative to Thallium 201 myocardial imaging in the evaluation of patients with coronary artery diseases. We studied 39 patients (37 men, mean age 56 +/- 9 years) with suspected coronary artery disease. All patients underwent 99mTc MIBI myocardial scintigraphy after stress and at rest. Coronary arteriography, performed within 1 month, showed significant (greater than or equal to 50%) stenosis of at least 1 epicardial coronary artery in 36 subjects. 99mTc MIBI myocardial scintigraphy exhibited 94% sensitivity (34/36 patients) and 100% specificity (3/3 subjects with normal coronary arteries). Sensitivity for individual vessel stenosis was 81% (96% for the left anterior descending artery, 65% for the circumflex artery and 79% for the right artery). Our data show that 99mTc MIBI myocardial scintigraphy is capable of evaluating patients with coronary artery diseases.

Contrast Media↗
PubMed2005

[Examination of resistance of lung adenocarcinoma cells to cisplatin by technetium-99m methoxyisobutyl isonitrile].

OBJECTIVE: To study whether technetium-99m methoxyisobutyl isonitrile ((99m)Tc-MIBI) can be used to examine the drug resistance of lung adenocarcinoma cells and to explore the efficiency of gensenoside Rh2 in reversing the resistance of adenocarcinoma cells to cisplatin (DDP). METHODS: Human lung adenocarcinoma cells of the line A549 sensitive to DDP and drug-resistant lung adenocarcinoma cells of the line A549DDP were cultured. DDP and gensenoside (Rh2) of different concentrations were added. Mthoxyisobutylisnitrile (MTT) method was used to test the inhibit concentration (IC) of DDP and Rh2 to the cells. The IC(50) of DDP to these 2 kinds of cells and its low-efficiency inhibition concentration (< or = IC(20)) to A549DDP cells, and the IC(5) of Rh2 to A549DDP cells were calculated. < or = IC20 was regarded as the low-efficiency concentration of DDP to A549DDP cells and IC(5) was regarded as the in-toxic concentration of Rh2 to A549DDP cells. A549DDP cells were divided into 4 groups: control group, added with normal saline; DDP group, added with DDP at the low-efficiency concentration; Rh2 group, added with in-toxic Rh2; and DDP + Rh2 group, added with DDP at the low-efficiency concentration and Rh2 at the in-toxic concentration. Cell apoptosis was detected by fluorescence microscopy and flow cytometry. Forty-seven hours after the stimulation by different drugs (99m)Tc-MIBI solution was added and 1 hour later the radioactivity of the cells was detected by gamma-counter. Twenty-four nude mice were divided into 4 equal groups: A549 group, inoculated with A549 cells and normal saline intraperitoneally; control group, inoculated with A549DPP cells and normal saline intraperitoneally; DDP group, inoculated with A549DDP cells and low-efficient DDP intraperitoneally; and Rh2 + DDP group, inoculated with A549DDP cells and low-efficient DDP and in-toxic Rh2intraperitoneally. The growth of tumor and survival of mice were observed. Before the inoculation of tumor cells, 4 mice were randomly selected to undergo single photons emission computed tomography (SPECT). Two months after the inoculation SPECT was performed on all mice. By the end of experiment all the mice were killed and their tumors underwent pathological examination. RESULTS: The IC(50) of DDP was 24 microM to A549 cells and 325 microM to A549DDP cells, with a resistance index of 13.54. When the concentration of Rh2 was < or = 10 microM there was no evident toxicity to A549DDP cells. The inhibition rate of 100 microM DDP to the A549DDP cells was 12%. After the cells were treated by 10 microM Rh2 and 100 microM DDP, the IC(50) of DDP to A549DDP cells was decreased to 94 microM; compared with the cells treated by 100 microM DDP alone, the reverse resistance of the latter was 3.5 times that of the former. Fluorescence microscopy showed that fluorescence was distributed uniformly in the nuclei of A549DD cells in the Rh2 group, DDP group, and the control group, and fluorescence were conglomerated like grain in the nuclei and apoptotic little substance appeared in the Rh2 + DDP group. The apoptotic rates of the control group, Rh2 group, DDP group, and DDP + Rh2 group were 6.1% +/- 1.0%, 5.9% +/- 1.1%, 8.2% +/- 1.0%, and 59.5% +/- 1.2% with a significant difference between the DDP + Rh2 group and control group (P < 0.01). There was no evident apoptotic apex in the control group, Rh2 group and DDP group, whereas there was distinct apoptotic apex in the Rh2 + DDP group. The radioactivity of (99m)Tc-MIBI could be incepted by the 4 groups. The radioactivity of the DDP + Rh2 group was significantly lower than that of the control group (P < 0.05) and there were no significant difference in radioactivity between the other 3 groups and the control group (all P > 0.05). The radioactivity of the A549 cells was significantly higher than that of the A549DDP cells (P < 0.01). Dense (99m)Tc-MIBI image of tumor could be seen in the A549 group mice, control group mice, and DDP group mice, the latter 2 groups with lighter images. No tumor image was seen in the Rh2 + DDP group mice. The R or R' value in the A549 group mice was remarkably higher than those in the control group and DDP group mice (both P < 0.05). CONCLUSION: (99m)Tc-MIBI can be used to examine the resistance of lung adenocarcinoma A549DDP cells. Gensenoside Rh2 of in-toxic concentration can reverse the resistance of lung adenocarcinoma A549DDP cells to cisplatin.

Adenocarcinoma↗
PubMed1992

Comparison of technetium-99m-MIBI and thallium-201-chloride uptake in primary thyroid lymphoma.

A case of primary thyroid lymphoma demonstrating uptake of 99mTc-hexakis-2-methoxy isobutyl isonitrile (MIBI) is presented. The 99mTc-MIBI image more clearly delineated the extent of tumor as demonstrated on CT compared to 201Tl-chloride and [99mTc]pertechnetate images. Following two courses of chemotherapy, repeat radionuclide studies and CT scan showed complete resolution of the thyroid tumor. Technetium-99m-MIBI may be useful in the assessment of disease activity and monitoring response to treatment in patients with lymphoma.

Female↗
PubMed2005

Effects of aging on regional cerebral blood flow assessed by using technetium Tc 99m hexamethylpropyleneamine oxime single-photon emission tomography with 3D stereotactic surface projection analysis.

OBJECTIVES: Although many previous reports have described age-related changes in regional cerebral blood flow (rCBF), none has used 3D stereotactic surface projection (3D-SSP) analysis, which is able to detect subtle and significant changes in rCBF. METHODS: The subjects were 31 healthy volunteers (16 men and 15 women; 50-79 years of age) without abnormal MR imaging and MR angiographic findings, cognitive impairment, or depression. For each subject, rCBF was evaluated by using technetium Tc 99m-radiolabeled hexamethylpropyleneamine oxime single-photon emission CT. Maps of rCBF were compared among different age groups (50-59, 60-69, and 70-79 years of age) by using 3D-SSP. The mean z score for each gyrus was calculated for each age group by using a recently developed stereotactic extraction estimation method. RESULTS: Significant age-related reductions in rCBF were seen in the bilateral cingulate gyri, left inferior gyrus, bilateral medial frontal gyri, left subcallosal gyrus, and left superior temporal gyrus. Extensive and constant reduction in rCBF occurred with increasing age in the bilateral anterior cingulate gyri, and the mean z score for this region was the highest among all the regions examined. CONCLUSION: The 3D-SSP analysis revealed that the greatest reduction in rCBF occurred within the bilateral anterior cingulate gyri in normal middle-aged and older subjects.

Aged↗
PubMed1992

Subcellular distribution and analysis of technetium-99m-MIBI in isolated perfused rat hearts.

To address the apparent discrepancy between cultured cells and whole heart preparations, Langendorff-perfused rat hearts loaded with hexakis (2-methoxyisobutyl isonitrile) technetium (I) (99mTc-MIBI) were fractionated by a standard differential centrifugation method and fractional contents of 99mTc-MIBI were correlated with the mitochondrial marker, malate dehydrogenase (MDH), and mitochondrial substrates. The "cytosolic" fraction nominally contained 89% +/- 3% of total 99mTc-MIBI, but also contained 91% +/- 1% of total MDH activity by this method. Chromatographic analysis of activity in the "cytosolic" fraction demonstrated greater than 95% of the agent was present as the original free cationic complex; binding to a small molecular weight cytosolic protein was not involved in localization. Addition of the mitochondrial uncoupler CCCP (5 microM) to both "mitochondrial" and "cell fragment" pellets released up to 84% +/- 8% of 99mTc-MIBI content and addition of the mitochondrial substrate succinate (10 microM) in the presence of rotenone (1 microM) enhanced 99mTc-MIBI content by up to 139% +/- 52% over the control. These correlative data from rat hearts indicate that approximately 90% of 99mTc-MIBI activity in vivo is associated with mitochondria in an energy-dependent manner as a free cationic complex, but migrates during fractionation/centrifugation.

Animals↗