Biomedical subjects

L Bajnok

Publications and source records attributed to L Bajnok.

15 recordsLinked to original sources

PubMed2005

Establishment of the hu-PBL-SCID mouse model for the investigation of thyroid cancer.

New experimental models of human neoplastic diseases attempt to mimic the human environment that fostered the development of disease in cancer patients. The aim of the present study was to establish a human lymphocyte-engrafted, severe combined immunodeficient (hu-PBL-SCID) mouse model to investigate thyroid cancer and to evaluate the potential use of this model for cancer immunotherapy. Thyroid neoplastic tissues were obtained from ten patients (one follicular adenoma, five papillary, one follicular, one anaplastic and two medullary cancers). One 8 x 4 x 3 millimeter sample from each tumor was cut into two pieces of identical size and transplanted into two SCID mice. In each case, one of the two mice was injected intraperitoneally with lymphocytes from the same tumor patient for the reconstitution of the human immune system (Group A), while the other animal received no lymphocytes (Group B). The engraftment of the tumors was successful in all cases. The growth rate was highly dependent on the histological type. When histologies were compared before implantation and after the removal of the implants, the characters of the tumors proved to be unchanged, except one case where an anaplastic cancer arose from a papillary tumor. Macrophages were present in all but one papillary cancer. All differentiated thyroid cancers were infiltrated by T and B lymphocytes. Lymphocytes and macrophages disappeared from 19/20 grafts by week 16. However, in one case from group A lymphocytes were detected four months after the transplantation. In another case from group A, one papillary cancer spontaneously decreased in size and disappeared. Before implantation, HLA-DR expression was detected in every papillary cancer. HLA-DR expression in the grafts was not seen in 3/5 cases by week 16. In conclusion, an animal model has been established for the investigation of human thyroid cancer, by which the analysis of anti-tumor immunity, as a postulate of immune therapy, may be possible.

Adult↗

PubMed2002

99m Tc-HMPAO labelled leukocyte scintigraphy in patients with rheumatoid arthritis: a comparison with disease activity.

The aim of this study was to test the applicability of 99mTc-hexamethylpropylene amine oxime (99mTc-HMPAO) labelled leukocyte joint scintigraphy in the assessment of disease activity in 21 patients with rheumatoid arthritis, and to compare leukocyte scintigraphy with the Disease Activity Score (DAS), a validated activity index developed by the European League Against Rheumatism (EULAR). Twenty-one patients with rheumatoid arthritis were investigated by using 99mTc-HMPAO labelled leukocyte joint scintigraphy. The clinical and laboratory data were recorded, and the DAS was calculated and compared with the scintigraphic results in each case. A relatively high DAS score (4.71+/-1.07) was found in the majority of patients. The degree of accumulation of 99mTc-HMPAO leukocytes showed no correlation with a patient's age, gender, duration of disease, use of disease modifying anti-rheumatic drugs (DMARDs), visual analogue scale (VAS), Richie index, DAS, or any laboratory parameters. In contrast, a significant correlation was found between the global regional accumulation of the labelled leukocytes of the hands and feet, and the swollen-joint count. It is concluded that radiolabelled leukocyte scintigraphy could become one of the promising methods in the assessment of disease activity in patients with rheumatoid arthritis.

Adult↗

PubMed2001

Technetium-99m-sestamibi/pertechnetate subtraction scintigraphy vs ultrasonography for preoperative localization in primary hyperparathyroidism.

A prospective study was performed to evaluate the efficacy of technetium-99m-sestamibi and technetium-99m-pertechnetate subtraction scanning and US for imaging parathyroid glands in primary hyperparathyroidism. Sixty-three patients were surgically treated for primary hyperparathyroidism (HPT). Preoperative scintigraphy and US were performed in all cases. Bilateral neck exploration was carried out on each patient. Results of radionuclide studies and US were compared with surgical and histological findings. In 57 patients with primary HPT the radionuclide scanning gave true-positive results. Four false-negative and two false-positive scintigrams were obtained. The sensitivity and the positive predictive value (PPV) of scintigraphy were 93 and 97%, respectively. Forty-one cases were correctly localized by the US. Seventeen US results were false negative and five were false positive. The sensitivity and the PPV for US were 71 and 89%, respectively. There was a statistically significant difference between the sensitivity of the scintigraphy compared with the US ( p=0.001). Sensitivities of radionuclide scans and US were higher for adenomas (100 and 83%) than for hyperplastic glands (75 and 40%). The sensitivity of technetium-99m-sestamibi and technetium-99m-pertechnetate subtraction scintigraphy was significantly higher compared with US. This sensitive method could help surgeons in performing a rapid and directed parathyroidectomy.

Adenoma↗

PubMed2000

The clinical usefulness of the fingers-to-palm ratio in different hand microcirculatory abnormalities.

A non-invasive nuclear medicine technique was developed to screen patients with painful hands so as to separate patients with a normal from those with an abnormal microcirculation of the hands in different clinical conditions. Such a technique is important, as the other methods available are either subjective or rather complicated. The study population consisted of 10 healthy individuals, 23 patients with Raynaud's syndrome and 15 patients with mixed connective tissue disease (MCTD). Sixty gamma-camera images of the hands (1 s each) were recorded after a bolus injection of 99Tcm-DTPA via a dorsal foot vein. Regions of interest were drawn on the summed images around the fingers and the palmar region. The fingers-to-palm ratio was then calculated from the total counts inside these regions of interest separately for each hand. The mean fingers-to-palm ratio was 0.94+/-0.18 (0.71-1.25) for the healthy group, 0.57+/-0.22 (0.21+/-1.11) for the MCTD group and 0.40+/-0.14 (0.18-0.77) for the Raynaud's patients. Analysis of variance showed these differences to be highly significant (P < 0.001). There were also significant differences between 6 MCTD patients in an active (mean 0.48) and nine patients in an inactive (mean 0.66) clinical state (two-sample t-test: P < 0.05). There were no significant differences between the fingers-to-palm ratios of the left and right hands of the same patients (one-sample t-test). Of the 23 primary Raynaud's patients, capillary microscopic data were pathological in only eight (34%). We conclude that our method is able to differentiate between patients with normal and those with abnormal microcirculation of the hands. Although measurement of the fingers-to-palm ratio is not a specific method, it is useful both for staging and in the follow-up of patients.

Adolescent↗

PubMed2000

Prevalence of iodine deficiency and goitre during pregnancy in east Hungary.

OBJECTIVE: To assess the iodine nutritional status and the prevalence of goitre during pregnancy in a region of Hungary that appeared to be iodine sufficient in previous studies. DESIGN: A cross-sectional voluntary screening study was organized in which 313 pregnant women participated. METHODS: Urine iodine concentration and the volume of the thyroid gland were measured in every woman. In the presence of low urinary iodine concentrations, goitre, or both, thyroid function tests were performed. RESULTS: Iodine deficiency was found in 57.1% of the pregnant women, and was severe in 15.6%. The volume of the thyroid gland was enlarged in 19.2% of individuals. Nodular goitre was found in 17 women (5.4%). The frequency of goitre and the mean thyroid volume were increased in the group of iodine-deficient women. In the 89 cases of iodine deficiency or goitre, thyrotrophin concentrations were in the normal range; however, the free triiodothyronine:free throxine ratio was increased in 97% of them, indicating that the thyroid gland was in a stimulated state in these individuals. CONCLUSIONS: Iodine deficiency with high prevalence of goitre was recognized among pregnant women in an area that previously appeared to be iodine sufficient. An unexpected mild iodine deficiency was also noted in the non-pregnant control group. Reassessment and continuous monitoring of iodine nutritional status is warranted even in populations that are apparently considered to be 'at no risk' of iodine deficiency, especially in pregnant women. Regular administration of iodine, starting at preconception or in early pregnancy and continuing during the period of nursing, is recommended in these regions.

Adult↗

PubMed1999

The role of technetium-99m methoxyisobutylisonitrile scintigraphy in the differential diagnosis of cold thyroid nodules.

Various diagnostic techniques have been successfully used in the clinical management of cold nodules; however, the decision on whether to employ surgery or a conservative treatment is not always easy. This study was designed to appraise the diagnostic value of technetium-99m methoxyisobutylisonitrile (MIBI) scintigraphy in the assessment of cold nodules detected using (99m)Tc-pertechnetate. Fifty-two patients were included in the study. All had already been selected for surgery, based on their clinical and laboratory findings, including fine-needle aspiration biopsy. The total number of cold nodules on (99m)Tc-pertechnetate scans was 59. The thyroid scan was performed 20-40 min after i.v. injection of 400 MBq of (99m)Tc-MIBI. Uptake of MIBI in thyroid nodules was compared with that in the surrounding normal thyroid tissue, and a score of between 0 and 3 was assigned to each nodule as follows: 0, cold; 1, decreased; 2, equal; 3, hot. Definitive histology revealed nodular goitre in 24 cases, adenoma in 19, thyroiditis in 1, differentiated cancer in 12, medullary cancer in 2, and anaplastic cancer in 1. None of the degenerative nodules were hot on MIBI scan, while the adenomas showed a variety of MIBI imaging patterns, most frequently the score 3 pattern. In the diagnosis of differentiated thyroid cancer the sensitivities of score 3 and score 2+3 MIBI uptake patterns were 83% (10/12) and 100%, respectively. The score 3 MIBI uptake pattern had a specificity of 100% and a positive predictive value of 100% with respect to thyroid (benign and malignant) neoplastic diseases, whereas a specificity of 72% and a positive predictive value of 43% were observed in the detection of differentiated cancer. After a cold nodule had been detected using (99m)Tc-pertechnetate, a second scan with high MIBI uptake increased by 7.8 times the probability that this nodule would be a differentiated cancer. In conclusion, (99m)Tc-MIBI scintigraphy is a useful method in the differential diagnosis of cold thyroid nodules if the primary aim is to differentiate degenerative from neoplastic diseases rather than to differentiate benign from malignant nodules. High MIBI uptake considerably increases the probability of a differentiated thyroid cancer and facilitates immediate surgical removal, while decreased uptake actually excludes it. We suggest a combination of fine-needle aspiration biopsy and MIBI scan as a routine diagnostic approach to cold thyroid nodules.

Biopsy, Needle↗

PubMed1999

Calculation of the radioiodine dose for the treatment of Graves' hyperthyroidism: is more than seven-thousand rad target dose necessary?

Some authors recently suggested a significant increase in the target dose of radioiodine treatment in Graves' disease. The aim of the present study was to investigate the impact of thyroid gland mass on the success rate of radioiodine treatment. For this purpose, the thyroid function of 105 consecutive Graves' patients was assessed 6 and 12 months after a 131I treatment and correlated to the gland mass. The patients were categorized according to the gland mass into small (< or = 30 g; 19 patients), medium size (31-50 g; 40 patients), and large size (> 50 g; 46 patients) groups (S, M, L groups, respectively). None of the patients received more than a 10,000-rad (100-Gy) target dose. During the calculation of administered 131I activity, late uptake measurement has also been routinely used, in addition to the usual maximal uptake parameter. The established effective half-life of 131I was highly variable (5 +/- 1.2 days; range: 2-7.6 days) and could not be predicted based on other clinical data without measuring an extended radioiodine uptake curve of the given patient. However, the correlation between the administered activity calculated from the complete set of uptake values and that of only a single late one was excellent (r = 0.99). Six months after the 131I treatment, hyperthyroidism was cured in 81% of patients with small and medium size thyroid glands, with 62% euthyroid and 19% hypothyroid ratios respectively. In the early phase of study for large goiters, the same linear mass activity function was used during calculation as in smaller glands. In these 17 patients the nonhyperthyroid result was comparable to the results of treatment of the small and medium size gland groups only after 1 year (77%), but the 6-month success rate was significantly lower (53%; p < 0.05). After obtaining these results, the usual 7000-rad target dose was increased to 8000-10,000 rad (depending on the gland mass) in another group of 29 patients with large thyroid glands that result in an acceptable 6-month success rate of 72%. In conclusion, instead of the "mCi 131I/g gland mass/maximal uptake" dose calculation, we suggest a method in which (1) the late 131I uptake measurement is taken into account and (2) for large goiters there is an additional dose adjustment, ie, increase is needed over the usual linear, size driven calculation. No overall increase of target dose over 10,000 rad is necessary if no antithyroid medication is given shortly before 131I treatment.

Adult↗

PubMed1995

[Clinical and biochemical parameters of patients with vascular stenosis in the lower extremities in the stage of intermittent claudication].

Clinical and biochemical parameters obtained by complex investigation of 100 patients suffering from intermittent claudication are presented by the authors. After taking the family and case history, we examined the patients and took laboratory tests including several lipid components, blood clotting factors and parameters influencing blood viscosity. The severity of peripheral vascular disease was defined by ankle/arm ratio, carotid arteries were studied by duplex sonography, coronary circulation was examined by ECG, exercise ECG and Thallium-201 isotopic myocardium scintigraphy. In conjunction with lower extremity vascular disease internal carotid stenosis was diagnosed in 62% and coronary stenosis in 52% of cases examined. In 35% all three regions were affected. The degree of carotid stenosis showed a strong correlation to the severity of the claudication, while in case of the coronary disease there was no connection proved, in spite of its high prevalence. Among the risk factors smoking was present in 89%, hypercholesterolaemia in 84%, hypertension in 54%, diabetes mellitus in 13%, impaired glucose tolerance in 42% and positive family history in 39% of cases. Smoking and accumulation of the risk factors showed correlation to the severity of the lower extremity vessel stenosis, while hypertension and carbohydrate metabolism disturbances showed significant correlations to the degree of carotid stenosis. From different lipid parameters only the cholesterol/HDL-cholesterol ratio showed significant correlation to the severity of the arteriosclerosis. The authors refer to intermittent claudication as the risk factor for carotid and coronary disease. They suggest the assessment of the cerebrovascular and cardiac risk in the patients. This way the optimal order of operative and/or non-operative therapy can be realized.

Adult↗

PubMed1995

[Estimation of perioperative cardiac risk by means of dipyridamole myocardial scintigraphy in patients undergoing vascular surgery on the lower limbs].

UNLABELLED: The vascular surgery of lower limbs has an increased cardiac risk that is related to the special surgical procedure and the high risk patient population. The myocardium scintigraphy after the administration of dipyridamole is a reliable stress testing, even despite claudication complaints. The authors performed dipyridamole stressed quantitative MIBI scintigraphy in 35 patients with peripheral arterial disease for the assessment of prognostic importance of the test. Twenty seven of the 29 patients (92%) referred for vascular surgery had a positive scintigram. In the two thirds of abnormal investigations (18 patients) there had been rest perfusion defects too, despite the fact that only one patient had a positive history regarding myocardial infarct (MI). Six cardiac complications occurred; all in the aorta crossclamping group (6/21, 29%): 5 nonfatal postoperative MI (4 of them were silent) and 1 patient died. All of the complicated cases showed positive preoperative scintigraphy but only 2 of them had stress induced perfusion defect; 4 patients presented fixed defects. CONCLUSIONS: 1. Especially the operations necessitating the cross-clamping of aorta are harmful. 2. Cardiac complications are frequently atypical in their clinical appearance. Thus, 24 and 48 hour after the vascular surgery ECG an enzyme investigations are indicated. 3. The fixed MIBI defects that can also be found at rest, have significant implications. 4. The most effective cardiac risk stratification before vascular surgery is a complex approach in which the clinical, ECG and imaging data are incorporated.

Adult↗

PubMed1994

Technetium-99m sestamibi scintigraphy for the assessment of lower extremity ischaemia in peripheral arterial disease.

Technetium-99m sestamibi was used for functional investigation of the muscle perfusion of lower extremities in 35 patients with peripheral vascular disease. The aim was to test what useful information could be obtained by additional imaging of the legs in patients referred for risk stratification with dipyridamole myocardial scanning. Posterior images were acquired over the thighs and calves after postocclusive reactive hyperaemia and at rest. Inter- and intraextremity ratios and differences between the stress and rest data were used for the assessment of abnormal circulation. Arteriography was performed in every case, and surgical procedures or transluminal angioplasty in 31 patients. To estimate diagnostic accuracy, the results of 99mTc-sestamibi scintigraphy were compared with those of angiography and the functional consequences of revascularization procedures. The sensitivity and specificity of 99mTc-sestamibi scintigraphy were 55% and 25%, respectively, with an overall accuracy of 50%. Apparently methodological error was not responsible for these poor results. Instead, a paradoxically high uptake of the radiopharmaceutical in muscles supplied by significantly stenosed vessels was identified as the main source of both false-negative and false-positive results. The phenomenon resembles the findings of a previous study involving delayed administration of thallium-201 after exercise. In conclusion, 99mTc-sestamibi scintigraphy has not proved sufficiently reliable to help in the management strategy for patients with peripheral vascular disease.

Dipyridamole↗

PubMed1993

[Experience with routine use of combined inhalation-perfusion lung scintigraphy. The most reliable diagnosis of pulmonary embolism].

The authors performed combined inhalation/perfusion scintigraphy in 217 patients with suspected pulmonary embolism in order to improve the diagnostic accuracy. Before the conventional perfusion study they also visualized the distribution of ventilation with a Venticis-II inhalator equipment. Regarding pulmonary embolism 10 (5%), 96 (44%), 39 (18%) investigations were "very low", "low", and "high probability", respectively. The inhalation study was successful in 93 percent of patients. These results were necessary in 141 patients. However, it was uncertain in 26% of cases (57 patients) concerning the diagnosis of pulmonary embolism. As the inhalation scintigraphy was applied without preselection, this study was unnecessary in 30%. On the other hand, if the combined studies had been performed only in the cases of previously proved segmental perfusion defects, the number of perfusion scintigraphies would have increased by 65%. The authors recommend the routine use of the inhalation lung scintigraphy.

Bronchial Provocation Tests↗

PubMed1992

[Accurate assessment of myocardial viability: complementation of Thallium-201 scintigraphy with a subsequent reinjection study].

Persistent myocardial thallium perfusion defects 3 to 4 hours after stress do not represent irreversible ischemia in every case. In many instances signs of reversibility show up 8-72 hours later or after rest reinjection. Authors performed additional investigations of redistribution in 64 patients with persistent defects. Rest reinjection was given to 11 patients and delayed redistribution was followed in the others. Persistent perfusion defects improved or disappeared in 13 percent of myocardial segments and 38 percent of patients. In 18% of segments late reverse redistribution was observed. The assessment of patients' state was significantly influenced by the results of the additional investigations in 19% of cases. Authors suggest that important information can be obtained about the viability of the myocardium by the extended studies even with the common planar method.

Adult↗

PubMed1992

Technetium-99m diethylene triamine penta-acetic acid and dimercaptosuccinic acid in the detection of a segmental branch stenosis of the renal artery by captopril renography.

We present a case in which a 39-year-old woman with correctable bilateral renovascular hypertension did not show abnormality during post-captopril technetium-99m dimercaptosuccinic acid (DMSA) study. Post-captopril 99mTc-diethylene triamine penta-acetic acid (DTPA) scintigraphy revealed the adverse effect of a stenosis of the artery supplying the upper part of her left kidney but failed to uncover the existence of severe multiple narrowings of the right renal artery. After bilateral renovascular reconstructive surgery, the hypertension completely disappeared. This case illustrates that DTPA may be more efficacious than DMSA in the detection of segmental loss of renal function induced by angiotensin converting enzyme inhibition.

Adult↗

PubMed1989

[Bone scintigraphy in uremic osteodystrophy].

99mTc-HEDP bone scan was carried out on 12 long-time haemodialysed patients, suffering from bone pains. X-ray examinations of the bone and laboratory tests (serum calcium, -phosphor, -alkaline phosphatase, -parathormone, -aluminium, -ferritin) were also performed. The scintigrams were evaluated by two semiquantitative scores. Based on diffuse, increased radiopharmacon uptake of the bones and more than five points in the Fogelman score 5 patients most likely had serious and 3 had moderate hyperparathyroidism. In two patients osteomalacy was presumed based on decreased radiopharmacon uptake of the bones, increased uptake of the soft tissues and zero Fogelman score. Mixed or other bone disease was suggested in two other patients. Good correlation was found between the results of bone scans, the parathormone values and the results of histology obtained after parathyreoidectomy of 4 patients and autopsy of two others. This non-invasive examination (ie. bone scan) is helpful in differential diagnosis of uraemic osteodystrophy and its wide use is proposed in domestic nephrological practice.

Adult↗

PubMedDate not supplied

Dipyridamole thallium-201 scintigraphy in patients with arteriosclerosis obliterans. Increased accuracy in identifying cardiac risk.

Forty-eight preselected patients (pts) with arteriosclerosis obliterans were investigated by dipyridamole thallium scintigraphy (DTS). No correlation was found between the distribution of positive or negative exercise ECG testing (ExECG) and isotopic risk-scores (P > 0.1 in the chi-square test). We assessed cardiac ischaemia in 12 pts with insufficient ExECG. Although only 2 pts had documented previous myocardial infarction, 20 pts exhibited irreversible perfusion defect. Silent reversible or irreversible ischaemia was identified in 12 pts (25%). Seven pts would not have been diagnosed to have coronary artery disease (CAD) even by ExECG. In conclusion, DTS was found very useful in these cases. We support a stepwise cardiac risk stratification before major vascular surgery.

Adult↗