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PubMed1985

99mTc bone scanning agents--I. Influence of experimental conditions on the formation and gel chromatography of 99mTc(Sn)pyrophosphate complexes.

The conversion of 99mTcO4- to 99mTc(Sn)pyrophosphate complexes was investigated under various experimental conditions. An increase of the Sn(II) concentration had a beneficial effect, whereas the ligand concentration had little effect. The pH had only a small influence over the range 2-8. Raising the pH to 10 resulted in the partial decomposition of the complexes, which could be reversed by lowering the pH. Furthermore, the occurrence of various complexes was investigated by means of gel chromatography on Biogel P-4 as a function of pH and of the Sn(II) and pyrophosphate concentrations. Four major fractions were found. A single preparation contained, however, no more than two major fractions. The formation of the different complexes was mainly governed by the pH and the ligand concentration. The influence of the eluent on the decomposition and interconversion of the complexes during chromatography was also studied. It appeared to be necessary that the eluent should have the same composition (except for 99mTcO4-) as the reaction mixture.

Bone and Bones↗
PubMed1997

Clinical efficacy of an optimized stannous fluoride dentifrice, Part 2: A 6-month plaque/gingivitis clinical study, northeast USA.

The objective of this 6-month, double-blind clinical study, conducted following the American Dental Association guidelines, was to investigate the efficacy of Colgate Optimized Stannous Fluoride (COSF) dentifrice for the control of supragingival dental plaque and gingivitis. This dentifrice contains 0.454% stannous fluoride, stannous chloride, polyphosphate, and citrate in a silica base. At the 3- and 6-month study examinations, the COSF dentifrice group exhibited statistically significant reductions in both plaque and gingivitis compared to the control dentifrice group. At the 6-month examination, the magnitude of these percent reductions exceeded 20% for all 4 parameters measured. Thus, the results of this study support the conclusion that the COSF dentifrice is efficacious for the control of supragingival plaque and gingivitis.

Adult↗
PubMed1997

Clinical efficacy of an optimized stannous fluoride dentifrice, Part 3: A 6-month plaque/gingivitis clinical study, southeast USA.

This 6-month, double-blind clinical study, also following the American Dental Association guidelines, investigated the efficacy of Colgate Optimized Stannous Fluoride (COSF) dentifrice in controlling supragingival dental plaque and gingivitis. The same dentifrice, containing 0.454% stannous fluoride, stannous chloride, polyphosphate, and citrate in a silica base was used. Adult men and women from the Atlanta, Georgia, area received an oral prophylaxis and were instructed to brush their teeth twice daily (morning and evening) for 1 minute with their assigned dentifrice, using a soft-bristled toothbrush. As in the first study, plaque and gingivitis examinations were conducted after 3 months and again after 6 months of using the dentifrices. At both the 3- and 6-month study examinations, the COSF dentifrice group exhibited statistically significant reductions in both plaque and gingivitis compared to the control dentifrice group. At the 6-month examination, the magnitude of these percent reductions exceeded 20% for all 4 parameters measured. Thus, the results of this study reflect those found in the New Jersey study, i.e., supporting the conclusion that the COSF dentifrice is efficacious for the control of supragingival plaque and gingivitis.

Adolescent↗
PubMed1981

Correlation of false negative myocardial infarct scintigraphy with postmortem studies.

Negative myocardial infarct scintigrams with 99mtechnetium stannous pyrophosphate (99mTc-PYP) were obtained in two patients with acute massive transmural infarct. Both patients died soon after scintigraphy. Because necropsy was performed within hours after death, we were able to correlate the distribution of the tracer within the acutely infarcted tissue with the myocardial scintigram. The clinical implication is that a single myocardial scintigram may be grossly inaccurate in detecting and quantifying infarct size. The scintigraphic findings should always be correlated with the electrocardiographic and enzymatic findings in evaluating patients with possible myocardial infarct.

Aged↗
PubMed1986

Acute and chronic effects of nicardipine on systolic and diastolic left ventricular performance in patients with heart failure: a pilot study.

Nicardipine is a new calcium ion antagonist with vasodilating properties which has been shown to be effective in the treatment of hypertension and angina. We have studied its effect on systolic and diastolic left ventricular function in patients with mild to moderate degrees of congestive heart failure. Ten male patients with New York Heart Association Class II and III heart failure underwent acute treatment with an intravenous infusion of nicardipine (10 mg over 10 minutes). A nuclear probe was used to monitor left ventricular ejection fraction, peak filling rate, and relative cardiac output. Blood pressure and heart rate were also measured. The blood pressure (mean +/- SD) fell from 133 +/- 26/86 +/- 11 mmHg to 103 +/- 22/69 +/- 13; the heart rate rose from 67 +/- 9 beats/min to 85 +/- 10; left ventricular ejection fraction from 31 +/- 7 to 38 +/- 6%; relative cardiac output from 24 +/- 9 to 41 +/- 11; peak filling rate from 1.18 +/- 0.4 end-diastolic volume per second to 1.82 +/- 0.4 (p less than 0.001 in all cases) at the end of infusion. After 4 weeks of chronic treatment in eight patients (20 mg to be taken three times daily (tds) in one and 40 mg tds in 7), the blood pressure and heart rate had returned to baseline values but the improvements in left ventricular ejection fraction, relative cardiac output, and peak filling rate were sustained; this was associated with functional improvement in all 8 patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1991

Gated cardiac blood pool studies in atrial fibrillation: role of cycle length windowing.

Cycle length windowing is gaining increasing acceptance in gated blood pool imaging of patients with atrial fibrillation (AF). The goals of this study were: to assess differences of ejection fraction (EF) in AF with and without windowing and to determine how EF varied with cycle length in patients with AF. Twenty patients with AF were prospectively studied by gated blood pool imaging, with simultaneous collection in each patient of 5-7 studies with cycle length windows spanning the cycle length histogram. Each window accepted beats of only a narrow range of cycle lengths. EF was determined for each of the narrow cycle length windows as well as for the entire gated blood pool study without cycle length windowing. For every patient an average of the windowed EFs was compared with the non-windowed EF. EF values were similar (mean windowed: 46.6; non-windowed: 45.5; P = 0.16), and there was a good correlation between the two techniques (r = 0.97). The data were then examined for a relationship of EF with cycle length. The difference from average windowed EF (delta EF) was calculated for each window and plotted vs. the cycle length of the center of each window. No predictable linear or nonlinear relationship of delta EF with window position was observed. Lack of predictable variation of EF with cycle length is likely due to lack of a predictable amount of ventricular filling for a given cycle length, as the amount of diastolic filling in AF depends on the random cycle length of the preceding beat.(ABSTRACT TRUNCATED AT 250 WORDS)

Atrial Fibrillation↗
PubMed1982

Labeling of human lymphocytes with 99mTc by means of stannous pyrophosphate. Scintigraphic applications.

An original 99mTc-labeling method applied to human lymphocytes is described. This technique is based on the use of stannous pyrophosphate to reduce sodium pertechnetate. The proposed procedure has two main advantages: firstly, the labeling process takes place in a neutral and buffered medium which prevents any cellular aggregation; secondly, the labeling yield obtained is compatible with scintigraphic studies in man. The influence of each parameter on the labeling quality had been studied as well as the binding stability of the technetium fixed on cells. A systematic study of lymphocyte surface markers, before and after labeling, has led to the suggestion that the labeling process seems to affect cellular membranes, probably because of the technetium binding. Finally, scintigraphic results are presented, the study being performed on eight healthy volunteers. These results are compared with those published by other authors who used either a different radioisotope or a different labeling method.

Humans↗
PubMed1995

Technetium-labelled red blood cell scintigraphy: is it useful in acute lower gastrointestinal bleeding?

Radionuclide scintigraphy is commonly utilized as a screening examination before performing more invasive procedures in the work-up of patients with lower gastrointestinal (GI) bleeding. We reviewed our institutional experience with technetium-labelled red blood cell scintigraphy (TRCS) in detecting and localising acute lower GI bleeding. The study group included 72 patients who had 80 red cells scans over a five year period. Thirty-eight scans were positive (47.5%), and 42 were negative (52.5%). Sites of lower GI bleeding were confirmed by endoscopy, arteriography, surgery and/or pathology in 22 of the 38 positive scans. There were four false-negative scans (9.5%). The overall sensitivity and specificity of TRCS in detecting lower GI bleeding was 84.6% (22/26) and 70.4% (38/54), respectively. The accuracy of localization of bleeding sites in the patients with confirmed positive scans was 72.7% (16/22). Thirty mesenteric arteriograms were performed on patients in this series. Eleven arteriograms were performed after negative TRCS; one was positive. Technetium-labelled red blood cell scintigraphy appears to be a useful screening examination for patients with lower GI bleeding who are hemodynamically stable. This may avoid the potential morbidity of arteriography in patients who are not actively bleeding.

Acute Disease↗
PubMed1996

Does impedance cardiography reliably estimate left ventricular ejection fraction?

OBJECTIVE: The objective of our study was to evaluate impedance cardiography (IMP) as a noninvasive method to determine the left ventricular ejection fraction (LVEF). METHODS. A total of 24 patients, 8 men and 16 women, aged 45.0 +/- 12.9 years, participated in the study. They used cardiotoxic chemotherapeutic drugs or suffered from cardiac failure. LVEF was measured by means of IMP (LVEFimp) and radionuclide ventriculography (LVEFnuc). LVEFimp was calculated in three ways. Capan and colleagues [13] proposed a formula in which LVEF (LVEFCap) can be calculated from the systolic time intervals, namely, left ventricular ejection time and preejection time. Judy and colleagues [14] described a systolic (S) and a diastolic (D) part in the first derivative curve of the impedance signal. The ratio S/D might equal the LVEF (LVEFJud). A new LVEF calculation was introduced (LVEFimp) in this study based on the first derivative of the impedance signal, the thoracic impedance, and heart rate. RESULTS: Mean LVEFCap was 59.9 +/- 8.4%, which did not differ from LVEFnuc (59.9 +/- 7.1%). However the correlation between both methods was not significant (r = 0.29). Mean LVEFJud was 63.9 +/- 17.4%, which was not significantly different from LVEFnuc, with a fair correlation (r = 0.55). Mean LVEFimp was 59.2 +/- 9.4%, with a better correlation with radionuclide ventriculography (r = 0.75). CONCLUSIONS: The results of this study indicate that the equations that have been used until now can be improved. The new equation provides reliable LVEF values in this group of patients.

Antibiotics, Antineoplastic↗
PubMed1983

The functional implications of scintigraphic measures of myocardial ischemia and infarction.

To compare serial functional and perfusion scintigraphic changes after myocardial infarction, we performed left ventricular (LV) cineangiograms and thallium (TI)-201 myocardial perfusion scintigrams before and 1 hour, 2 days, 9 days, and 1 month after closed chest coronary occlusion in 14 dogs as survival permitted. Survivors were studied with technetium-99m (stannous) pyrophosphate (TcPYP) scintigrams at 48 hours, and at postmortem examination infarction was documented and measured after nitroblue tetrazolium (NBT) staining. The TcPYP image was abnormal in 10 dogs, each of which had infarcts on NBT staining measuring 3 to 23 gm. In all 14 dogs, perfusion scintigrams became abnormal and LV ejection fraction (EF) fell when measured within 48 hours of occlusion. In the nine late survivors studied over 1 week after the event, perfusion scintigrams and EF improved in those which developed infarcts and normalized in those without infarction. The decrement in LVEF after coronary occlusion generally showed serial improvement and correlated with the size of the defect in the accompanying TI-201 scintigram (r = 0.74). TI-201 defect size seen in late studies correlated well with NBT infarct size (r = 0.89) and TcPYP image infarct size (r = 0.82), as it did with the decrement in LVEF noted in late studies (r = 0.86). The results suggest that early perfusion scintigrams together with TcPYP images may be useful for estimating the amount of reversible dysfunction after coronary occlusion.

Animals↗
PubMed1982

Detection of acute right ventricular infarction by right precordial electrocardiography.

The value of 0.1 mV or greater of S-T segment elevation in at least one right precordial lead (V4R to V6R) in defining right ventricular myocardial infarction was assessed prospectively in 43 subjects (33 consecutive patients with enzymatically confirmed infarction of varying type and location, 4 patients with unstable angina and 6 healthy volunteers). Patients with acute myocardial infarction were studied with radionuclide ventriculography and technetium-99m stannous pyrophosphate myocardial scintigraphy 18.2 +/- 14.3 (mean +/- standard deviation) and 85.1 +/- 18.0 hours after the onset of symptoms, respectively. Eleven patients (Group A: 9 patients with transmural inferior infarction, 1 with transmural inferolateral infarction and 1 with transmural anteroseptal infarction) demonstrated right precordial S-T segment elevation and 22 patients (Group B: 6 patients with transmural inferior infarction, 2 with transmural posterior infarction, 3 with transmural inferolateral infarction, 3 with transmural anteroseptal infarction, 3 with transmural extensive anterior infarction, 4 with subendocardial anterior infarction and 1 with unclassified infarction) did not. Right ventricular ejection fraction was significantly lower in Group A (0.47 +/- 0.11) than in Group B (0.60 +/- 0.12) (p less than 0.01). Right ventricular total wall motion score was 63.8 +/- 15.6 percent of normal in Group A versus 94.3 +/- 8.5 percent in Group B (p less than 0.001). Technetium-99m pyrophosphate uptake (2+ or greater) over the right ventricle occurred in nine patients (81.8 percent) in Group A and in one patient (4.5 percent) in Group B (p less than 0.001). No patient with unstable angina and no healthy volunteer had S-T segment elevation in a right precordial lead. S-T segment elevation of 0.1 mV or greater in one or more of leads V4R to V6R is both highly sensitive (90 percent) and specific (91 percent) in identifying acute right ventricular infarction.

Aged↗
PubMed1983

Prolonged angina pectoris and persistent negative T waves in the precordial leads: response to atrial pacing and to methoxamine-induced hypertension.

In 18 consecutive patients without a history of myocardial infarction (MI), prolonged angina pectoris with persistent negative T waves in the precordial leads was associated with a high frequency of in-hospital spontaneous angina (14 of 18, 78%), usually accompanied by S-T segment elevation, and occasionally in-hospital MI (4 of 18, 22%). Angina and MI always involved the electrocardiographic leads with negative T waves. Coronary arteriography, performed in 16 patients, revealed greater than or equal to 90% proximal diameter reduction of the left anterior descending (LAD) coronary artery in 14 patients. No patient had severe narrowing of all 3 major coronary arteries, but the 3 who had 100% LAD occlusion lacked collateral circulation. The ejection fraction was greater than or equal to 50% in 13 patients. Atrial pacing performed in 11 patients at an average rate of 142 beats/min produced a 1.0 mm S-T segment change in only 5 patients (45%), 3 of whom had an associated lactate production. Arterial systemic hypertension induced by methoxamine in 14 patients caused reversal of negative T waves without significant S-T segment shifts or chest pain and failed to elicit lactate extraction abnormalities in each of the 5 patients in whom it was determined. Thus, prolonged angina with persistent negative T waves in the precordial leads is almost invariably associated with a critical and proximal LAD obstruction, severe narrowing of 1 or 2 coronary arteries, and poor or absent collateral vessels. The relatively preserved coronary reserve in 55% of our patients suggests that negative T waves do not represent active myocardial ischemia. The study also suggests that transient "positivization" of the negative T waves may not necessarily relate to myocardial ischemia when associated with acute systemic hypertension.

Adult↗
PubMed1986

Left ventricular dysfunction induced by cold exposure in patients with systemic sclerosis.

Raynaud's phenomenon and cardiac abnormalities are frequent in patients with systemic sclerosis. Radionuclide ventriculograms were obtained in 16 patients with Raynaud's phenomenon and systemic sclerosis or the related CREST syndrome and in 11 normal volunteers in order to evaluate changes in left ventricular function that might be induced by exposure to cold. Left ventricular regional wall motion abnormalities developed in nine of 16 patients during cooling compared with only one of 11 control subjects, despite a comparable rise in mean arterial pressure (p less than 0.02). The abnormalities occurred in seven of 11 patients with systemic sclerosis, one of four with CREST syndrome, and one with Raynaud's disease. To test the potential protective effect of nifedipine, radionuclide ventriculograms were then obtained during cooling after sublingual nifedipine (20 mg). Only five of 13 patients had wall motion abnormalities, and the severity of the abnormalities was significantly less than during the first cooling period (p = 0.03). Five of eight patients who had cold-induced wall motion abnormalities during the first cooling period had none after nifedipine, whereas two other patients demonstrated small abnormalities only during the second cooling period after treatment with nifedipine. It is concluded that cold induces segmental myocardial dysfunction in patients with systemic sclerosis and that nifedipine may blunt the severity of this abnormal response.

Adult↗
PubMed1988

99mTc-SN-pyrophosphate scintigraphy following traumatic posterior dislocation of the hip.

Avascular necrosis of the head of the femur is a serious complication of traumatic dislocation of the hip joint; therefore 99mTc-SN-pyrophosphate scintigraphy was carried out 10 to 14 weeks (average 12 weeks) after the injury on 12 patients to determine whether it was possible to demonstrate reduced or no activity of the head of the femur before development of radiological avascular necrosis of the head of the femur. Increased activity was observed in 9 of 11 hips with fracture-dislocation of the head of the femur, acetabulum or both, and normal activity was demonstrated in the contralateral hip of all patients. During the follow-up period avascular necrosis of the head of the femur developed in four hips from 6 to 20 months after the accident. It is concluded that 99mTc-SN-pyrophosphate scintigraphy 12 weeks after traumatic dislocation of the hip was unable to identify hips at risk of later development of avascular necrosis of the head of the femur.

Adolescent↗
PubMed1982

A new method for radiolabeling of Gelfoam particles with 99mTc.

Embolization of the spleen and other organs using Gelfoam has recently gained acceptance as a therapeutic procedure. A simple non-invasive determination of the placement of Gelfoam particles is needed and this requires labeling Gelfoam with radionuclides. We have developed a simple, reliable reproducible, and inexpensive method of labeling Gelfoam with 99mTc using commercial sulfur colloid kits. Optimal reaction conditions include room temperature incubation for 60 min at 12 rpm rotation. In vitro stability indicated no loss of 99mTc activity up to 3 h post labeling. Imaging of intra-arterially placed 99mTc Gelfoam at 1 h and 24 h in animals and humans has consistently produced well-defined images of the radioemboli.

Animals↗
PubMed1988

Postural exercise abnormalities in symptomatic patients with mitral valve prolapse.

The hemodynamics of the supine and upright exercise response in 16 symptomatic women with mitral valve prolapse (Group I) was compared with that in 8 asymptomatic normal control women (Group II). All subjects had supine and upright echocardiography and phonocardiography at rest and none demonstrated mitral regurgitation. All participants then underwent same day graded bicycle exercise, with simultaneous radionuclide angiography in both the upright and the supine posture. Catecholamines were measured, and a variety of volumetric and hemodynamic data were obtained. Group I (patients with mitral valve prolapse) demonstrated a reduced exercise tolerance, especially during upright exercise, as measured by both total exercise duration and maximal work load achieved. Mean total catecholamine measurements were similar between the two study groups at comparable mean heart rate, mean blood pressure and mean rate-pressure (double) product. No difference was observed in the ratio of right to left ventricular stroke counts at rest or during exercise regardless of posture, suggesting that exercise-induced mitral regurgitation did not occur. A difference was noted, however, in left ventricular end-diastolic volume index. At rest, Group I patients exhibited a 42% decrease in this index when sitting upright, and this difference from supine values persisted at submaximal (300 kpm/min) and peak work loads (34 and 29% difference, respectively). This contrasted with the control subjects whose upright end-diastolic volumes at rest, at 300 kpm/min and at peak exercise were reduced 21, 10 and 3%, respectively, compared with supine values. Cardiac index measurements reflected the reduced left ventricular end-diastolic volume observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗