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At least 397 records · Page 22Linked to original sources
PubMed1990

Contemporary techniques for the radioisotopic evaluation of the dilated urinary tract.

Regardless of one's approach to the evaluation of hydronephrosis, nuclear imaging should be part of every child's evaluation, as it is the only imaging modality capable of providing significant renal function information. The studies can easily be performed on an outpatient basis without sedation. Diuretic renal scintigraphy is deceptively simple to perform, and commitment to detail is exceedingly important if the results are to be valid. Radioisotope transit time may also be helpful, although its calculation is technically difficult. Determination of the function of the kidneys individually is possible by several methods.

Child↗
PubMed1979

[Evaluation of unilateral renal function in urinary obstruction. A comparison of various radioisotope methods (author's transl)].

The catheter-free determination of the unilateral 131I-hippuran clearance correlates well with the unilateral clearance determination with 99mTc-DMSA in patients without obstruction. In patients with unilateral chronic obstruction the clearance of 131I-hippuran on the average is 13% higher than the clearance determined by the DMSA method. After successful correction of the obstruction the two values are identical. 123I-hippuran is foundin the renal pelvis already after 90 seconds in some cases of marked chronic obstruction. The functioning part of the involved kidney is therefore possibly overestimated whereas the DMSA uptake reflects the actual function. Both radioisotope methods should be applied preoperatively in order to evaluate the individual renal function. Functional scintigraphy in patients with obstruction should preferably be carried out with 123I-hippuran.

Humans↗
PubMed1990

Radioisotopic pulmonary lobectomy: feasibility study in dogs.

In search for an alternate treatment for inoperable cancer of the lung in humans, we investigated the possibility that introduction of radioactive material into a selected lobe of the canine lung would effectively destroy that lobe without systemic effects or radiation injury to adjacent organs. Ten million ion exchange microspheres labeled with 740 MBq of phosphorus-32 (32P) were injected through a catheter placed in a selected lobar branch of a pulmonary artery in 12 anesthetized dogs. Six additional dogs served as controls and received 10 million microspheres not labeled with 32P. Organs were harvested from 1 wk to 12 mo after injection and examined grossly and histologically. There was progressive organization and contraction of each necrosed 32P treated lobe which was reduced to a scarred remnant by 12 mo, whereas only minimal inflammatory changes occurred in controls. Of the 32P injected dose, 94% remained in injected lobe, 4%-5% in nontargeted lobes and less than 0.08% in blood. Radioactivity in liver, kidneys, spleen, heart, and bone marrow was less than 0.1% for each organ. Thus, large doses of radiation in the order of 1,500 Gy can be effectively delivered to a selected lobe to produce a "radioisotopic pulmonary lobectomy."

Animals↗
PubMed1989

[Usefulness of radioisotope (RI) deconvolution analysis with Tc-99m-DTPA in transplanted kidney].

In 50 renal transplant recipients, we performed radioisotope (RI) deconvolution analysis, as reported by O'Reilly, in 179 renograms from dynamic renal scanning with Tc-99m-DTPA and obtained MTT (mean transit time) and H0 (initial height) values. We found characteristic features of various graft conditions using the combination of MTT and H0. The mean H0 value was greater in normally functioning grafted kidneys than in kidneys with other states. The mean MTT in the normal group was about 2 min. In the acute rejection group, the mean H0 value was lower and the mean MTT was more prolonged compared with the normal group. In ATN group, the mean MTT was similar to that in the acute rejection group, whereas the mean H0 value was lower. In the chronic rejection group, the mean MTT was similar to that in the normal group, but the mean H0 value showed a lower one. The hydronephrosis group had an extremely prolonged MTT. This study indicated that the combination of H0 and MTT obtained from RI deconvolution analysis is a valuable means of understanding the condition of renal grafts.

Graft Rejection↗
PubMed1989

Diagnostic efficacy of dynamic radiothallium uptake in thyroid nodules determined by computer-assisted scintigraphy. Reevaluation of a radioisotopic procedure.

Radiothallium (201Tl) has been proposed as a tracer in nuclear medicine for the diagnosis of cold thyroid nodules. Its potassium-mimetic characteristics, like those of 131Cs, can provide information on its turnover in the thyroid nodules; this serves as a basis for the distinction between benign and malignant thyroid tumours. The author presents a study on the diagnostic efficacy of 201Tl as a tracer for thyroid nodules with the aim of evaluating the dynamic uptake and the biodistribution of 201Tl after intravenous injection of 555-740 kBq/kg. A quantitative analysis was made by continuous scanning of 201Tl distribution during the first 20-30 min following thallium injection, with further surveys from 40 to 60 min or more when fixation in a nodule was demonstrated. The ratio between 201Tl uptakes in the nodule and in healthy tissue (density index) was calculated and a multiparametric analysis of the corresponding activity/time curves was performed. This study included 176 patients. Concordance between clinico-histological diagnosis and radio-isotopic findings was demonstrated in 102 out of 106 colloidocystic goitres, in 42 out of 48 benign nodules including thyroiditis, and in 21 out of 22 malignant tumours; a significant statistical difference in the density index between solid and cystic nodules, but no difference between benign and malignant nodules; and a different 201Tl dynamic behaviour in nodules of different nature, with a clear statistical difference in the thallium release between malignant nodular and healthy tissue (nodular disappearance index). This method can improve the diagnosis value of scintigraphy for thyroid nodules enhancing the sensitivity of the radioisotopic applications in comparison with other non-invasive techniques.

Adenocarcinoma↗
PubMed1989

[The evaluation of the therapeutic effect on acute myocardial infarction by radioisotope method--assessment of the intravenous injection of urokinase and comparison with the results of PTCR + PTCA].

The therapeutic effect of intravenous injection of Urokinase (UK method) on acute myocardial infarction (AMI) was studied and compared with the results of the therapeutic effect of PTCR + PTCA. The subjects comprise 108 cases with AMI, and a radioisotope examination was performed in the acute stage to calculate LVEF and Tl-defect ratio (Tl-DR). Measured by the UK method, Tl-DR in the group given 1.2 X 10(6) units of UK was 1.63 +/- 0.8, which was lower than the 2.4 +/- 1.33 for the group given 9.6 X 10(5) unit of UK, whereas a favorable therapeutic effect was obtained in both groups compared to 3.5 +/- 2.5 in the control group. In the group given UK within 6 hours after the onset of AMI, favorable results were obtained for LVEF (44.5 +/- 11.2%) and Tl-DR (1.68 +/- 0.82). The UK group showed as better results as the PTCR + PTCA group for LVEF (42.3 +/- 11.3 vs. 38.1 +/- 7.4) and Tl-DR (2.10 +/- 1.19 vs. 2.09 +/- 0.62). In both the UK and PTCR + PTCA groups, Tl-DR was well maintained despite an increase in the peak CPK and a decrease in LVEF, and, therefore, the conservation of stunned myocardium in the acute stage was suggested. From the above, it was concluded that the UK method is useful for treating AMI.

Aged↗
PubMed1988

Comparison of two radioisotope dilution assay kits for measuring vitamin B12 in gruel.

The results obtained using two commercially available radioisotope dilution (RID) assay kits for determining vitamin B12 were compared. Comparison of the results obtained with the two RID methods gave a correlation coefficient of 0.9390 for gruel samples. The results obtained with one of the kits were slightly lower, probably due to a difference in the RID assay techniques.

Edible Grain↗
PubMed1987

[Assessment of uteroplacental circulation with radioisotopes].

The authors have evaluated placental blood flow using a non-invasive radioisotopic approach, with the intravenous administration of 1 mCi 113mIn. The method is evaluated in 20 normal pregnancies, in 24 patients with intrauterine growth retardation, in 8 patients with iso-Rh-immunization and in 9 patients with gestational diabetes. In the group with intrauterine growth retardation 2 pregnancies with extensive fetal malformations were included. In one case without evident histological placental alteration the index was 3.94 at 34 weeks of gestation and 5.62 at 36 weeks of gestation. In the second one with placental infarcts the index was 3.46 at 38 weeks of gestation. Normal pregnancies showed a flow index of 5.50 +/- 1.57 (1 s.d.) units compared to the pathological pregnancies value of 2.74 +/- 0.90 (1 s.d.) units. (p less than 0.001). The conclusions drawn are: The method is very well suited to clinical evaluation of placental blood flow. The evaluation of placental blood flow cannot be directly equated with fetal development as it is not its only determinant. This method is a indirect index of placental function in small for gestational age fetuses with malformations.

Congenital Abnormalities↗
PubMedDate not supplied

[A study of the stability of liposomes from the total lipid fraction of E. coli by means of fluorescence spectroscopy and a radioisotope probe].

Stability of liposomes from total fraction of E. coli lipids was studied by their ability to preserve encapsulated substance under different incubation conditions--+4 degrees C and +37 degrees C for some concentrations of CaCl2. Two types of vesicules were used: small ones obtained by ultrasonic treatment and larger ones obtained after successive treatment of lipid suspension with Ca2+ ions and EDTA. It has been shown by spectrofluorimetry and radioisotope probe that for both studied types of liposomes their stability decreases with an increase of CaCl2 concentration and rise of temperature. The effect similar to Ca2+ was produced by Mg+2 ions, but not by Na+ ions. Large liposomes are significantly less stable formations than the small ones. Ca+2 ions were shown to induce at first liposome aggregation and then their destruction. Possible action mechanism of metal ions of the second group on liposome stability, the pattern of initiated membrane disturbances and application of these structures as agents during transfer of biologically active compounds in the cells are discussed.

Calcium Chloride↗
PubMed1988

[Radioisotope studies of the spontaneous course of postoperative deep venous thrombosis].

Radiofibrinogen tests were applied to 88 surgical and urological patients with postoperative thrombosis of deep veins to establish point and time of thrombus origin and courses taken by thrombi. Most of the thrombi thus recorded had originated from venous bulges of the calf, the soleus sinus. These accounted for 83 per cent of all thrombi detected. Progress was in all cases in proximal direction, towards the popliteofemoral veins. The intraoperative phase was found to be the most dangerous juncture for the development of thrombi, with 36 per cent of all thrombi emerging on the day of surgery and another 22 per cent on the first and second postoperative days. Prophylaxis against thrombosis, therefore, should be initiated prior to surgical intervention in any case. Bilateral thrombosis was recorded from 22 cases. Sixty-one per cent of all thromboses were localised on the left side, and 81 per cent of all postoperative thromboses were clinically latent. There were six non-lethal outbreaks of pulmonary embolism and one lethal case. While the majority of calf vein thromboses was relatively harmless, the risk of pulmonary embolism increased considerably, as thrombi emerged at the level of the popliteal vein. Radioisotope investigation can be used to identify deep vein thrombosis and to figure out those patients in whom pulmonary embolism or chronic venous insufficiency may be expected to develop.

Fibrinogen↗
PubMed1986

Determination of vitamin B12 in gruel by a radioisotope dilution assay.

The results obtained by a radioisotope dilution (RID) method for the determination of vitamin B12 in gruel were compared with those obtained by a standard microbiological assay with Lactobacillus leichmannii. A commercially available RID assay kit was used. A very high correlation between the results from the RID method and the microbiological method was found when the extraction procedure was the same. Digestion with buffer solution at pH 4.6 was shown to be the most suitable extraction method. The RID assay is an acceptable method for routine determinations of vitamin B12 in gruel.

Biological Assay↗
PubMed1985

The diagnosis of vitamin B12 deficiency in sheep: comparison of serum vitamin B12 levels measured by a microbiological and a radioisotope dilution technique.

Serum vitamin B12 from 6 sheep fed a diet containing 0.06 mg cobalt per kg dry matter (DM) was analysed by a radioisotope dilution (RID) technique. The results were compared with values obtained by a microbiological method (Lactobacillus leichmannii - ATCC 7830) specific for "true" vitamin B12. Serum vitamin B12 concentrations were four to six times greater during the 16 weeks experimental period with the RID method as compared to the microbiological technique. During the course of the experiment, values obtained by the RID method remained superior to the threshold value (200 pg B 12/ml) of the microbiological method. This investigation indicates that the RID method is not suitable for the rapid diagnosis of vitamin B12 deficiency in subclinically cobalt-deficient sheep.

Animals↗
PubMed1985

Noninvasive radioisotopic assessment of pulmonary vascular protein leak. Experimental studies and potential clinical applications.

Noninvasive, double-radioisotope measurement of pulmonary vascular protein leak is a specific and sensitive method for assessing pulmonary vascular permeability. It is sensitive enough to detect increases in vascular protein leak that are too small to produce detectable increases in gravimetric lung water. A simple method for calculating protein leak index reliably reflects expected changes in pulmonary vascular permeability in a broad range of lung injury conditions. This method of measurement may have significant experimental and clinical applications in the study of lung-injury-induced edema, and especially in the evaluation of levels of injury associated with increased permeability but not significant edema. In particular, this method may help to distinguish between increased-permeability edema, such as that which occurs in the adult respiratory distress syndrome, and other types of pulmonary edema in humans.

Animals↗
PubMed1986

Trace element profiles in murine Lewis lung carcinoma by radioisotope-induced X-ray fluorescence.

Trace element profiles of various body tissues and tumor were established during growth of the Lewis lung tumor (LLT) with the use of radioisotope-induced X-ray fluorescence (RIXRF) analysis. The LLT, a highly malignant experimental murine tumor, resembles its human counterpart, has a well-defined life cycle, and kills its host in 30 days. When compared with normal controls, Zn, Br, and Rb levels in lung, liver, and skeletal muscle and Zn and Sr levels in bone from tumor-bearing mice exhibited large fluctuations at critical points in the tumor life cycle. In addition, the 24-day primary tumor trace element profile resembled that of its tissue of origin, normal lung, and was quite different from other normal tissues studied. These findings indicate that trace element profiles may help in the diagnosis, staging, and monitoring of disease. RIXRF is an excellent technique for this purpose because it is sensitive and relatively nondestructive of samples and has multielement capabilities.

Animals↗
PubMed1979

[Comparative studies of radioisotope uroflowmetry (author's transl)].

Radioisotope uroflowmetry allows continuous recording of urinary stream with determination of maximum and mean urine flow rate, duration of voiding and residual urine without urethral catheterisation. By the aid of twenty simulated tests and nine examinated patients the precision of this method was investigated by comparing our results with the findings of simultaneously recorded mictiographic measurement. The flow curves and the maximum flow rate show a high correlation.

Humans↗
PubMed1975

Detection of cell-bound immunoglobulins by a radioisotopic micro-mixed hemadsorption reaction with technetium-99m-labeled erythrocytes.

The mixed hemadsorption (MHA) reaction detects antibodies reactive with cell surface antigens by means of antiglobulin-coated indicator erythrocytes. We have developed a radioisotopic modification which employs sheep erythrocytes (SRBC) that have been prelabeled with technetium-99m (99mTc), a high specific acitivity metastable gamma-emitter of short half life. The 99mTc MHA reaction was performed on human and murine cells cultured in Micro-test II plated with six replicate wells per serum dilution. Antibody activity in species-specific xenoantisera and mono- and polyspecific alloantisera was detected in high titer. The sensitivity of 99mTc micro-mixed hemadsorption was 2 times that of the visual assessment of mixed hemadsorption, 100 to 200 times that of the 125-I-mixed antiglobulin reaction and 500 to 1000 times more sensitive than indirect immunofluorescence. The assay system was applied successfully to confirm the species of origin of a panel of previously karyotyped human and mouse cell lines. Our results indicate that the 99mTc micro-mixed hemadsorption method is a rapid, sensitive, quantitative test for the detection of cell surface antigens and membrane reactive antibodies.

Animals↗