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Biomedical subjects

S Takács

Publications and source records attributed to S Takács.

At least 19 recordsLinked to original sources
PubMed2005

Experimental study of the cross-sections of alpha-particle induced reactions on 209Bi.

alpha-particle-induced nuclear reactions for generation of (211)At used in therapeutic nuclear medicine and possible contaminants were investigated with the stacked foil activation technique on natural bismuth targets up to E(alpha)=39 MeV. Excitation functions are reported for the reactions (209)Bi(alpha,2n)(211)At, (209)Bi(alpha,3n)(210)At and (209)Bi(alpha,x)(210)Po. Results obtained from direct alpha-emission measurements and gamma-spectra from decay products are compared and correspond well with earlier literature values. Thick target yields have been deduced from the experimental cross-sections and optimised production pathways for minimal contamination are presented. A comparison with the results of the theoretical model code ALICE-IPPE is discussed.

Journal Article↗
PubMed2005

Activation cross-sections of long-lived products of proton-induced nuclear reactions on zinc.

In the frame of a systematic study of excitation functions induced by medium energy protons, the activation cross-sections on natural zinc were investigated for different applications. Excitation functions for production of 66,67Ga, 62,65,69mZn, 64Cu, 57Ni, 55,56,57,58Co and 52,54Mn radioisotopes were measured by the stacked foil technique in the energy range of 26-67 MeV. Results were compared with the earlier reported experimental data and theoretical calculations based on the ALICE-IPPE code. Experimental data are presented for the first time for most of the products in the investigated energy range. Applications of the measured data for validating the cross-sections on highly enriched isotopic Zn targets and for thin layer activation method are discussed.

Computer Simulation↗
PubMed2005

Cross-section measurement of the 169 Tm p,n reaction for the production of the therapeutic radionuclide 169 Yb and comparison with its reactor-based generation.

The radionuclide (169)Yb (T(1/2)=32.0 d) is potentially important for internal radiotherapy. It is generally produced using a nuclear reactor. In this work the possibility of its production at a cyclotron was investigated. A detailed determination of the excitation function of the (169)Tm(p,n)(169)Yb reaction was done over the proton energy range up to 45 MeV using the stacked-foil technique and high-resolution gamma-ray spectrometry. The integral yield of (169)Yb was calculated. Over the optimum energy range E(P)=16-->7 MeV the yield amounts to 1.5 MBq/micro Ah and is thus rather low. A comparison of this production route with the established (168)Yb(n,gamma)(169)Yb reaction at a nuclear reactor is given. The (169)Yb yield via the reactor route is by several orders of magnitude higher than by the cyclotron method. The latter procedure, however, leads to "no-carrier-added" product.

Isotope Labeling↗
PubMed2001

Communication ecology of webbing clothes moth: 1. Semiochemical-mediated location and suitability of larval habitat.

We tested two hypotheses: 1) that there is semiochemical-mediated attraction of male and female webbing clothes moth (WCM), Tineola bisselliella (Hum.) (Lepidoptera: Tineidae) to suitable larval habitat; and 2) that selection of optimal larval habitat has fitness consequences. In binary or ternary choice arena bioassay experiments that prevented WCM from contacting test stimuli, males and females were attracted to dried but untanned animal pelts (red squirrel, muskrat, beaver, coyote, red fox and bobcat) and preserved horseshoe crab but not to unprocessed sheep's wool, demonstrating semiochemical-based recognition of, and discrimination between, potential larval habitats. Selection of habitat has fitness consequences for ovipositing females, because significantly more male and female WCM completed development when the larval diet consisted of intact animal pelt (hide plus hair) rather than hide or hair alone. Equal attraction of male WCM to muskrat pelt volatiles in Porapak Q or solvent extracts of muskrat pelts indicated that volatile semiochemicals could be obtained by both methods.

Adaptation, Physiological↗
PubMed2001

Communication ecology of webbing clothes moth: 2. Identification of semiochemicals mediating attraction of adults to larval habitat.

Our objective was to identify the semiochemicals that mediate attraction of the webbing clothes moth (WCM), Tineola bisselliella (Lepidoptera: Tineidae), to suitable larval habitat. Coupled gas chromatographic-electroantennographic detection (GC-EAD) analyses of Porapak Q-captured bioactive volatiles from horseshoe crab, and dried but untanned vertebrate pelts revealed numerous EAD-active volatiles. These volatiles were identified by comparative GC-mass spectrometry and GC-EAD analyses of natural and synthetic compounds. A blend of 28 synthetic candidate semiochemicals attracted both male and female WCM. Experiments deleting various components determined that saturated aldehydes--but not unsaturated aldehydes, saturated hydrocarbons, saturated alcohols, or ketones--were essential for blend attractiveness. A blend of nonanal, the single most attractive aldehyde, in combination with geranylacetone was more attractive to WCM than the 28-component blend or dried, untanned animal pelt. Selection of larval habitat resides more with male than female WCM, as indicated by stronger EAD responses from male than female antennae to habitat-derived semiochemicals, and more selective and early response to habitat cues by males than females. Exploitation of nonanal and geranylacetone as resource-derived semiochemicals by both adult WCM and its larval parasitoid, Apanteles carpatus, is an example of convergent semiochemical parsimony.

Age Factors↗
PubMed1992

Acute and "long-term" genotoxic effects of CdCl2 on testes of mice.

The effects of Cd administered ip in a single carcinogenic dose (1 mg Cd/kg body weight) into male CFLP mice were investigated on the histological and cytogenetic status of the testes of the animals on d 3 and 6 mo after the Cd injection. There were some characteristic histological changes in the testes of the mice on d 3 after Cd treatment: the presence of interstitial hemorrhages, the death of Leydig cells, sterile necroses of tubular elements, and numerous atypical mitoses of the spermatocytes. A significant increase compared with the control was found only in the number of numerical chromosome aberrations in the Cd-treated group. Six months later, a significant difference compared with the control was found only in the relative weight of the testes in the treated group. There were soon no detectable effects of Cd on the histological picture of the testes and on the spermatocytes.

Animals↗
PubMed1992

Trace elements in the human blood, cerebrospinal and amniotic fluid.

Human biological samples using the atomic emission method. The concentration of 27 micro- and macro elements was specified in a total number of 1221. Some of the patients tested were under hospital treatment because of chronic disease (727 persons), others were blood donors (71 persons) or pregnant women and newborn infants (107-107 persons, respectively). In the serum samples of the tested persons the concentration of barium, mercury, nickel and gallium showed characteristic differences. Concentrations of many micro elements in the serum and cerebrospinal fluid changed with age and sex. The tendency becomes characteristic after the age of 45 and 60, respectively. The concentration of elements in the blood serum of mothers and their newborn infants seems to be nearly identical with a considerable deviation observed only in case of aluminum, barium and iron (significant difference). The detected elements can pass through the placenta. This particularly applies to lead because the average lead concentration in the serum of newborn infants is 159 micrograms/litre even at birth.

Aging↗
PubMed1991

Trace elements in the environment and in human organs: analysis according to domicile and sex.

Copper, zinc, lead and cadmium content of the kidney, liver and lung derived from 1072 autopsies has been determined. The content of lead and cadmium in liver, the content of copper, cadmium and zinc in lung of the rural population (541 cases) was higher than those of the urban population (531 cases). The cadmium content difference of the lung was found to be significant (p less than 0.05). In the lung of the urban population the Zn/Cu relation was better (0.80) than in rural population (0.39). In the kidney and lung of the urban males (297 cases) the cadmium content was significantly higher than in females (234 cases). In the liver the differences were not significant. The Zn/Cu relation was found to be high in both sexes in kidney and in lung respectively (r = 0.90-0.87). In the rural population the sex difference are characteristic: The lead and cadmium content are significantly lower in the kidney and lung of the women. The lead content in the women's liver is lower (p less than 0.05).

Environmental Monitoring↗
PubMed1987

Trace elements in the environment and in human organs. I. Methods and results.

The authors have determined by spectrophotometry the copper, zinc, lead, and cadmium content of the kidney, liver, lung, and adrenal derived from 1072 autopsies. The metallic content of food and drink was examined and the daily quantity consumed was stated by measuring and calculation. According to the results in Hungary the daily ingestion of these four microelements is small, as reflected by the metal content of the organs. An average 75% of the kidney's whole cadmium content is present in the cortex of the kidney. Lead in the medulla and zinc in the cortex are found in larger quantities. Analyzing the distribution according to sexes it was found that lead in the liver and kidney and cadmium in the kidney and lung of women is significantly lower than in the male. However, the element content in the adrenal is significantly higher for zinc and cadmium in women. The cadmium distribution in the kidney is similar to the essential elements. The correlation of the element pairs is better in the kidney and lung (Zn-Cu is 0.55 in the kidney and 0.51 in the lung).

Cadmium↗
PubMed1987

Nitrate content of drinking water and tumours of the digestive organs.

A survey of malignant tumours involving the digestive organs and the bladder registered in 7 districts and 5 towns in the County of Borsod was conducted. Between 1967 and 1983, the number of registered cases of tumours involving the digestive organs (including liver) was 3558 (incidence rate 691.6%) and that of bladder tumours amounted to 293 (incidence rate 56.9%). Males were more frequently affected than females with these types of tumour. Among the lesions of the digestive tract gastric tumours prevailed followed by tumours of the colon and of the rectum. The nitrate and nitrite contents of the drinking water consumed by the patients were also investigated. The average values were compared with the tumour incidence rate of the respective area. In most areas, the trend coincided i.e. lower morbidity was associated with lower average nitrate values. The data available revealed that about two-thirds (64.0%) of tumour cases affecting the digestive organs were living in areas where the nitrate concentration of drinking water was over 100 mg l-1. Analyses based on the various types of disease yielded similar results. The incidence of tumours in patients, drinking water with a nitrate content of 0 to 100 mg l-1 was 34.1 to 41.1%. The possible inter relationships between these figures are analysed and the implementation of additional epidemiologic and pathophysiologic investigations are suggested.

Digestive System Neoplasms↗