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1.
Int J Legal Med ; 2024 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-38987428

RESUMO

This study explores the reliability of four established legal age threshold estimation approaches in a Croatian sample. We applied Haavikko stages, Demirjian stages, Olze's third molar eruption stages, and second and third molar maturity indices measurement in 593 orthopantomograms of Croatian children and adolescents aged 11.00-20.99 years old. The left mandibular second and third molar were assessed. Logistic regression analysis was conducted to test the significance of predictive variables. Logistic Receiver operating characteristic (ROC) curves were performed to evaluate the classification ability of variables for estimating 14- and 16-year-old thresholds. The areas under the ROC curve (AUC), accuracy (Acc), sensitivity (Se), specificity (Sp), Positive Likelihood Ratio (LR +), Negative Likelihood Ratio (LR-), and Bayes post-test probability (Bayes PTP) were calculated to evaluate classification performance. Results suggest that the combination of I2M&I3M is the best classifier for the 14-year-old threshold (AUC = 0.879); for males alone, I2M is an even better classifier (AUC = 0.881). The highest Acc 80.1% (95%CI, 75.9%-83.9%), Bayes PTP 86.5% (95%CI, 82.8%-89.7%) and Sp 88.9% (95%CI, 83.0%-93.3%) were by I3M < 0.81 & I2M < 0.03 in total samples; the highest Acc 86.1% (80.6%- 90.6%), Bayes PTP 87.2% (95%CI, 81.7%- 91.4%) and Sp 87.8% (95%CI, 78.2%- 94.3%) were by I2M < 0.01 in males, Acc of Haavikko Ac and Demirjian H stage in second molar is very close with slightly lower Bayes PTP and Sp. I3M is a good classifier for 16-year-old threshold (AUC = 0.889). The cut-off value I3M < 0.34 can be used to classify the 16-year-old threshold with Acc of 80.6% (95%CI, 77.2%-83.7%), Sp of 83.4% (95%CI, 79.0%-87.3%), and 81.7% (95%CI, 78.4%-84.8%) Bayes PTP. In conclusion, to classify the 14-year-old threshold, a pair of cut-off values I3M < 0.81 & I2M < 0.03 can be used in Croatian females; I2M < 0.01, Demirjian H stage, Haavikko Ac stage in second molar, and the pair I3M < 0.81 & I2M < 0.03 can all be used in Croatian males. I3M < 0.34 can classify the 16-year-old threshold in Croatian populations.

2.
J Appl Clin Med Phys ; 25(2): e14240, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38150580

RESUMO

BACKGROUND: Monte Carlo (MC) simulations or measurements in anthropomorphic phantoms are recommended for estimating fetal dose in pregnant patients in radiotherapy. Among the many existing phantoms, there is no commercially available physical phantom representing the entire pregnant woman. PURPOSE: In this study, the development of a low-cost, physical pregnant female phantom was demonstrated using commercially available materials. This phantom is based on the previously published computational phantom. METHODS: Three tissue substitution materials (soft tissue, lung and bone tissue substitution) were developed. To verify Tena's substitution tissue materials, their radiation properties were assessed and compared to ICRP and ICRU materials using MC simulations in MV radiotherapy beams. Validation of the physical phantom was performed by comparing fetal doses obtained by measurements in the phantom with fetal doses obtained by MC simulations in computational phantom, during an MV photon breast radiotherapy treatment. RESULTS: Materials used for building Tena phantom are matched to ICRU materials using physical density, radiation absorption properties and effective atomic number. MC simulations showed that percentage depth doses of Tena and ICRU material comply within 5% for soft and lung tissue, up to 25 cm depth. In the bone tissue, the discrepancy is higher, but again within 5% up to the depth of 5 cm. When the phantom was used for fetal dose measurements in MV photon breast radiotherapy, measured fetal doses complied with fetal doses calculated using MC simulation within 15%. CONCLUSIONS: Physical anthropomorphic phantom of pregnant patient can be manufactured using commercial materials and with low expenses. The files needed for 3D printing are now freely available. This enables further studies and comparison of numerical and physical experiments in diagnostic radiology or radiotherapy.


Assuntos
Gestantes , Radiometria , Gravidez , Humanos , Feminino , Fótons/uso terapêutico , Planejamento da Radioterapia Assistida por Computador , Simulação por Computador , Imagens de Fantasmas , Método de Monte Carlo , Dosagem Radioterapêutica
3.
Int J Mol Sci ; 24(16)2023 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-37628928

RESUMO

Dipeptidyl peptidase III (DPP III, EC 3.4.14.4) is a monozinc metalloexopeptidase that hydrolyzes dipeptides from the N-terminus of peptides consisting of three or more amino acids. Recently, DPP III has attracted great interest from scientists, and numerous studies have been conducted showing that it is involved in the regulation of various physiological processes. Since it is the only metalloenzyme among the dipeptidyl peptidases, we considered it important to study the process of binding and exchange of physiologically relevant metal dications in DPP III. Using fluorimetry, we measured the Kd values for the binding of Zn2+, Cu2+, and Co2+ to the catalytic site, and using isothermal titration calorimetry (ITC), we measured the Kd values for the binding of these metals to an additional binding site. The structure of the catalytic metal's binding site is known from previous studies, and in this work, the affinities for this site were calculated for Zn2+, Cu2+, Co2+, and Mn2+ using the QM approach. The structures of the additional binding sites for the Zn2+ and Cu2+ were also identified, and MD simulations showed that two Cu2+ ions bound to the catalytic and inhibitory sites exchanged less frequently than the Zn2+ ions bound to these sites.


Assuntos
Dipeptidil Peptidases e Tripeptidil Peptidases , Humanos , Sítios de Ligação , Domínio Catalítico , Domínios Proteicos
4.
Int J Mol Sci ; 24(18)2023 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-37762480

RESUMO

Dipeptidyl peptidase 3 (DPP3) is a zinc-dependent exopeptidase with broad specificity for four to eight amino acid residue substrates. It has a role in the regulation of oxidative stress response NRF2-KEAP1 pathway through the interaction with KEAP1. We have conducted stable isotope labeling by amino acids in a cell culture coupled to mass spectrometry (SILAC-MS) interactome analysis of TRex HEK293T cells using DPP3 as bait and identified SH2 Domain-Containing Protein 3C (SH2D3C) as prey. SH2D3C is one of three members of a family of proteins that contain both the SH2 domain and a domain similar to guanine nucleotide exchange factor domains of Ras family GTPases (Ras GEF-like domain), named novel SH2-containing proteins (NSP). NSPs, including SH2D3C (NSP3), are adaptor proteins involved in the regulation of adhesion, migration, tissue organization, and immune response. We have shown that SH2D3C binds to DPP3 through its C-terminal Ras GEF-like domain, detected the colocalization of the proteins in living cells, and confirmed direct interaction in the cytosol and membrane ruffles. Computational analysis also confirmed the binding of the C-terminal domain of SH2D3C to DPP3, but the exact model could not be discerned. This is the first indication that DPP3 and SH2D3C are interacting partners, and further studies to elucidate the physiological significance of this interaction are on the way.

5.
Int J Legal Med ; 136(6): 1685-1696, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36131089

RESUMO

AIM: This study aimed to evaluate the accuracy and precision of the Cameriere European formula, Demirjian, Haavikko, and Willems methods for estimating dental age in a sample of children with permanent dentition in Croatia. MATERIAL AND METHODS: The study consisted of a sample of 1576 panoramic radiographs; a sub-sample of 84 OPGs, in which all first seven mandibular teeth were maturated, was excluded from the study. A final sample of 1492 (704 males and 788 females) aged 6.0 to 13.9 years was evaluated. Seven mandibular teeth from the left side of the mandible were analyzed, and dental age (DA) was determined by the Cameriere European formula, Demirjian method from 1976, Haavikko, and Willems methods and compared to chronological age (CA). In addition, the mean age difference (DA-CA), the mean absolute error (MAE) between dental and chronological age, the percentage of the individuals of dental age within ± 0.25 to ± 2 years of chronological age, and intra-observer and inter-observer statistics were calculated. RESULTS: The Cameriere European formula estimated the best dental age compared to the chronological age; the mean underestimation was - 0.4 years for both sexes, Haavikko underestimated by - 0.17 years, while Demirjian and Willems overestimated by 1.02 years and 0.48 years, respectively. The most significant difference showed the Demirjian method in 11-year-old and 12-year-old females. The MAE were 0.50 years, 1.01 years, 0.61 years, and 0.78 years in males and 0.51 years, 1.18 years, 0.61 years, and 0.70 years in females for the Cameriere European formula, Haavikko, Willems, and Demirjian methods, respectively. Furthermore, the Cameriere European formula showed the highest proportions of individuals with DA within ± 0.5 year difference of the CA, 61.5% in males and 59.6% in females. In addition, the Cameriere method showed the best intra-observer and inter-observer agreements. CONCLUSIONS: Although the Demirjian method was used previously in Croatian children for legal, medical, and clinical purposes, the Cameriere European formula, Haavikko, and Willems were more accurate in the tested sample. According to our findings, the Cameriere European formula showed the best accuracy and precision in dental age assessment in Croatian children following Haavikko, and we recommend it as the method of the first choice in forensic and clinical analyses.


Assuntos
Determinação da Idade pelos Dentes , Dente , Determinação da Idade pelos Dentes/métodos , Criança , Croácia , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Radiografia Panorâmica , Dente/diagnóstico por imagem , Calcificação de Dente
6.
Phys Chem Chem Phys ; 23(23): 13267-13275, 2021 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-34095907

RESUMO

Dipeptidyl peptidase III (DPP III), a zinc-dependent exopeptidase, is widely distributed in organisms and present in almost all human tissues. In addition to its involvement in protein catabolism, it plays a role in oxidative stress and blood pressure regulation, and there is evidence of its involvement in pain modulation. Excess zinc ions have been found to inhibit its hydrolytic activity, but the binding affinity, binding site geometry, and mechanism of inhibitory activity have been unknown. Using several different computational approaches, we determined the inhibitory zinc ion binding site, its coordination and relative binding affinity. During some simulations the translocation of the zinc ion from the inhibitory to the catalytic binding site was observed, accompanied by movement of the catalytic zinc ion toward the exit of the substrate binding site. The traced behavior suggests an associative type of metal ion exchange, in which the formation of the ternary complex between enzyme and two metal ions precedes the exit of the catalytic metal ion. Differently from our previous findings that binding of a peptide induces partial opening of hDPP III, the globularity of the protein did not change in MD simulations of the hermorphin-like peptide bound to hDPP III with two zinc ions. However, the entrance to the interdomain cleft widens during Zn diffusion into the protein and was found to be the highest energy barrier in the process of metal translocation from the solvent to the active site. Finally, we discuss why excess zinc reduces enzyme activity.


Assuntos
Dipeptidil Peptidases e Tripeptidil Peptidases/antagonistas & inibidores , Inibidores de Proteases/farmacologia , Zinco/farmacologia , Sítios de Ligação/efeitos dos fármacos , Dipeptidil Peptidases e Tripeptidil Peptidases/metabolismo , Humanos , Íons/química , Íons/farmacologia , Simulação de Dinâmica Molecular , Inibidores de Proteases/química , Zinco/química
7.
J Chem Inf Model ; 59(8): 3437-3453, 2019 08 26.
Artigo em Inglês | MEDLINE | ID: mdl-31274304

RESUMO

The main aim of this work was to find parameters for the zinc ion in human dipeptidyl peptidase III (DPP III) active site that would enable its reliable modeling. Since the parameters publicly available failed to reproduce the zinc ion coordination in the enzyme, we developed a new set of the hybrid bonded/nonbonded parameters for the zinc ion suitable for molecular modeling of the human DPP III, dynamics, and ligand binding. The parameters allowed exchange of the water molecules coordinating the zinc ion and proved to be robust enough to enable reliable modeling not only of human DPP III and its orthologues but also of the other zinc-dependent peptidases with the zinc ion coordination similar to that in dipeptidyl peptidases III, i.e., peptidases with the zinc ion coordinated with two histidines and one glutamate. The new parameters were tested on a set of 21 different systems comprising 8 different peptidases, 5 DPP III orthologues, thermolysin, neprilysin, and aminopeptidase N, and the results are summarized in the second part of the article.


Assuntos
Dipeptidil Peptidases e Tripeptidil Peptidases/química , Dipeptidil Peptidases e Tripeptidil Peptidases/metabolismo , Zinco/metabolismo , Humanos , Imidazóis/química , Conformação Proteica , Prótons
8.
J Radiol Prot ; 38(4): 1412-1427, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30264736

RESUMO

OBJECTIVE: To investigate the relationship of the effective dose and dose area product (DAP) in dental cone beam computed tomography (CBCT) examinations and to propose conversion factors for estimation of effective doses of the patients using DAP. Dependence of organ doses on DAP was also investigated. MATERIALS AND METHODS: Different exposure geometries in Cranex3Dx CBCT device were simulated using Monte Carlo simulation and computational anthropomorphic phantom. Then organ doses and effective dose for every exposure geometry was compared to DAP and analysed. RESULTS: The effective dose in all simulated CBCT protocols and positions with 180° tube rotation ranged from 5 µSv for 50 × 50 mm2 field of view (FOV) localised on one tooth using lowest resolution to 265 µSv for the largest FOV and highest resolution. In case of 360° tube rotation the effective dose ranges from 6 to 332 µSv for the same FOV sizes and positions as well as resolutions as in 180° tube rotation. CONCLUSIONS: Though the DAP introduces a large uncertainty in the risk measure in dental CBCT, it represents the dose and FOV size which are the most important scanning parameters affecting the dose. To decrease uncertainty in the risk measure, the effective dose has to be estimated for usual clinical positions of the FOV.


Assuntos
Tomografia Computadorizada de Feixe Cônico , Doses de Radiação , Radiografia Dentária/métodos , Humanos , Imagens de Fantasmas , Radiometria
9.
Int J Legal Med ; 130(4): 1109-1120, 2016 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-26972694

RESUMO

Assessment of legal age, also known as age of majority, is a controversial issue as there are few body biomarkers or evidence during late adolescence differentiating a subject from being a minor or adult. The third molar was recognized as a suitable site for age examination in late adolescence. We analyzed the development of the left mandibular third molar by the third molar maturity index (I3M) and a specific cut-off value of I3M = 0.08, established by Cameriere et al. in 2008 and used it for discriminating between minors and adult black Africans from Gaborone, Botswana. A final sample of panoramic radiographs (OPTs) of 1294 people (582 males and 712 females) aged between 13 and 23 years was evaluated. The real age decreased as I3M gradually increased. There was no statistically significant difference in the third molar development evaluated using I3M between males and females (p > 0.05) across different I3M classes. Results of 2 × 2 contingency tables for different cut-off values indicated that I3M = 0.08 was useful in discriminating between adults and minors. Precisely, for I3M = 0.08, the values of accuracy or overall fraction of correctly classified were 0.91 in males with a 95 % confidence interval (95 % CI) of 0.88 to 0.93 and 0.92 (95 % CI, 0.90 to 0.93) in females. Values of sensitivity of the test or the proportion of participants being 18 years and older were 0.88 (95 % CI, 0.87 to 0.90) in males and 0.88 (95 % CI, 0.90 to 0.93) in females, while values of specificity or proportion of individuals younger than 18 who have I3M <0.08 were 0.94 (95 % CI, 0.91 to 0.96) in males and 0.96 (95 % CI, 0.94 to 0.98) in females. Positive predictive values of the test, where the participants whose I3M <0.08 were adults, were 0.94 (95 % CI 0.91 to 0.96) in males and 0.97 (95 % CI, 0.94 to 0.98) in females, while negative predictive values of the test, where the participants whose I3M was ≥0.08 were minors, were 0.88 (95 % CI 0.85 to 0.90) in males and 0.97 (95 % CI, 0.94 to 0.98) in females. The likelihood ratios of the positive test (LR+) were 13.67 (95 % CI, 9.21 to 21.02) in males and 23.73 (95 % CI, 14.20 to 42.28) in females, while likelihood ratios of the negative test (LR-) were 0.12 (95 % CI 0.10 to 0.16) in males and 0.12 (95 % CI, 0.11 to 0.15) in females. Bayes post-test probabilities, p, were 0.94 (95 % CI 0.90 to 0.98) in males and 0.97 (95 %CI, 0.93 to 1.00) in females. These results indicate with high accuracy that I3M may be a useful alternative method in legal and forensic practice to discriminate individuals of black African origin who are around the legal adult age of 18 years in Botswana. Further studies should address the usefulness of this method and specific cut-off for different adolescent populations.


Assuntos
Determinação da Idade pelos Dentes/métodos , Dente Serotino/diagnóstico por imagem , Dente Serotino/crescimento & desenvolvimento , Adolescente , População Negra , Botsuana , Feminino , Odontologia Legal , Humanos , Masculino , Valor Preditivo dos Testes , Radiografia Panorâmica , Adulto Jovem
10.
Ann Vasc Surg ; 29(8): 1598-605, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26319145

RESUMO

BACKGROUND: Stroke prevention includes surgery for significant stenosis of internal carotid artery (ICA). Consensus on a standard approach lacks and one alternative approach is eversion carotid endarterectomy (eCEA). To overcome disadvantages of eCEA, we developed extended-eversion carotid endarterectomy (exeCEA). Aiming to investigate hemodynamics after different surgical approaches, we created computational fluid dynamics (CFD) models of exeCEA and eCEA with included progressing lumen narrowing, representation of artery restenosis at the incision line. METHODS: Blood flow velocities, volume flow rates, and wall shear stress (WSS) were established in carotid arteries from models of eCEA and exeCEA with included increasing groove (1, 1.5, 2, and 2.5 mm) at the "incision line", under input pressure of 120 and 150 mm Hg. RESULTS: For the corresponding restenosis grade, models of exeCEA had a larger orifice toward ICA, lower blood flow velocities and higher volume flow rates in ICA, with lower volume flow rates in external carotid artery. WSS values in ICA of exeCEA models were lower than in eCEA models, later reaching the thrombotic range. CONCLUSIONS: CFD showed better hemodynamic properties in exeCEA models, indicating presented approach might be better at preserving brain perfusion.


Assuntos
Estenose das Carótidas/fisiopatologia , Estenose das Carótidas/cirurgia , Endarterectomia das Carótidas/métodos , Pressão Arterial/fisiologia , Velocidade do Fluxo Sanguíneo/fisiologia , Feminino , Humanos , Pessoa de Meia-Idade , Modelagem Computacional Específica para o Paciente , Fluxo Sanguíneo Regional/fisiologia , Resistência Vascular/fisiologia
11.
Coll Antropol ; 38(1): 255-60, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24851626

RESUMO

In the aetiology of maxillofacial injuries, car accidents, violence, sports injuries and lately war injuries are frequently mentioned. The purpose of this study was to exhibit and analyse types of jaw injuries on bodies exhumed from massive and individual graves located in regions temporarily occupied during the War in Croatia that lasted from 1991 to 1995. The sample was the post-mortal documentation of the orofacial region (set of teeth, photographs, radiographic images) of 1068 victims exhumed from massive grave sites in Croatia. The jaw traumatism was analysed on the whole sample as well as on individual graves, whilst the analysis of trauma frequency was performed separately. Descriptive statistics were computed and the value of P < .05 was accepted as statistically significant. Results of this study showed that out of 1068 examined corpses, 332 had midface and lower face fractures, which was 31.1% of the total number. Lower face fractures were more frequent with 28.1%. Age related frequency analysis showed a significant dependency. There were 34.6% of fractures in the under 30 age group, 34.2% in those aged 30-60, while 21.3% of fractures were noted in the over 60 age group. Female bodies had the lowest number of jaw fractures regardless of the osteoporotic changes. The results of this study suggest that younger and middle aged persons were molested more. Jaw fractures suggest ante-mortal molestation. In females, the more likely fracture causes were the falls of the bodies into the graves or body to body hits.


Assuntos
Exumação , Arcada Osseodentária/lesões , Traumatismos Maxilofaciais/epidemiologia , Crimes de Guerra/estatística & dados numéricos , Guerra , Adulto , Croácia , Feminino , Patologia Legal , Humanos , Masculino , Pessoa de Meia-Idade
12.
Korean J Orthod ; 53(3): 194-204, 2023 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-37226512

RESUMO

Objective: To investigate sex-specific correlations between the dimensions of permanent canines and the anterior Bolton ratio and to construct a statistical model capable of identifying the sex of an unknown subject. Methods: Odontometric data were collected from 121 plaster study models derived from Caucasian orthodontic patients aged 12-17 years at the pretreatment stage by measuring the dimensions of the permanent canines and Bolton's anterior ratio. Sixteen variables were collected for each subject: 12 dimensions of the permanent canines, sex, age, anterior Bolton ratio, and Angle's classification. Data were analyzed using inferential statistics, principal component analysis, and artificial neural network modeling. Results: Sex-specific differences were identified in all odontometric variables, and an artificial neural network model was prepared that used odontometric variables for predicting the sex of the participants with an accuracy of > 80%. This model can be applied for forensic purposes, and its accuracy can be further improved by adding data collected from new subjects or adding new variables for existing subjects. The improvement in the accuracy of the model was demonstrated by an increase in the percentage of accurate predictions from 72.0-78.1% to 77.8-85.7% after the anterior Bolton ratio and age were added. Conclusions: The described artificial neural network model combines forensic dentistry and orthodontics to improve subject recognition by expanding the initial space of odontometric variables and adding orthodontic parameters.

13.
Dent J (Basel) ; 11(7)2023 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-37504241

RESUMO

Sex assessment is a key part of forensic analysis to establish the identity of unknown deceased individuals. Previous studies have shown that canines are the most dimorphic teeth, but population-specific data are necessary for forensic methods. This study explores sex dimorphism in canine crown dimensions and morphology in a contemporary Croatian population. The material consisted of 302 dental casts (147 females, 155 males) of orthodontic patients and dental students (11-25 years). The distal accessory ridge (DAR) of the upper and lower canines was evaluated using the Arizona State University Dental Anthropology System. Mesiodistal (MD) and buccolingual (BL) crown dimensions were measured on 120 casts. Sex differences in MD and BL dimensions were significant (p < 0.05) for all the canines (upper and lower, left and right), while in DAR only for lower canines (p < 0.000001). When all variables were put into the model, backward stepwise discriminant function analysis isolated lower canine DAR and lower left canine MD as the two independent variables differentiating sex. Using these two variables, a discriminant function formula allowed for sex determination with an accuracy of 73.5%. This study shows that both canine crown morphology and dimensions are useful for sex determination, especially for lower canines. These methods can be applied to children, as lower canines erupt at about 9 years of age.

14.
Phys Med ; 115: 103159, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37852021

RESUMO

It is well known that foetuses are highly sensitive to ionising radiation and special attention to justification and optimisation of radiological procedures involving a pregnant patient is required. A task to review, validate and compare different approaches to managing the pregnant patient and to estimating the associated foetal doses arising from a diagnostic or interventional radiology (DIR) procedure was designed in the framework of EURADOS working group 12. As a first step, a survey of radiation protection practice including dosimetry considerations among EURADOS members was performed using online questionnaire. Then, to evaluate the possible differences in the estimated foetal doses, a comparison of assessed dose values was made for three cases of pregnant patients that underwent different CT procedures. More than 120 professionals from 108 institutions and 17 countries that are involved in managing pregnant patients undergoing DIR procedures answered the questionnaire. Most of the respondents use national or hospital guidelines on the management of pregnant patients undergoing DIR procedures. However, the guidelines differ considerably among respondents. Comparison of foetal dose assessments performed by dosimetry experts showed the variety of methods used as well as large variability of estimated foetal doses in all three cases. Although European and International commission on radiation protection guidelines already exist, they are more than 20 years old and, in some aspects, they are obsolete. This paper shows that there is a need to revise and update these guidelines.


Assuntos
Proteção Radiológica , Radiologia Intervencionista , Gravidez , Feminino , Humanos , Adulto Jovem , Adulto , Doses de Radiação , Proteção Radiológica/métodos , Radiografia , Radiometria
15.
J Biol Inorg Chem ; 17(5): 801-15, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22526564

RESUMO

This study elucidates the role of the protein structure in the catalysis of ß-diketone cleavage at the three-histidine metal center of diketone cleaving enzyme (Dke1) by computational methods in correlation with kinetic and mutational analyses. Molecular dynamics simulations, using quantum mechanically deduced parameters for the nonheme Fe(II) cofactor, were performed and showed a distinct organization of the hydrophilic triad in the free and substrate-ligated wild-type enzyme. It is shown that in the free species, the Fe(II) center is coordinated to three histidines and one glutamate, whereas the substrate-ligated, catalytically competent enzyme-substrate complex has an Fe(II) center with three-histidine coordination, with a small fraction of three-histidine, one-glutamate coordination. The substrate binding modes and channels for the traffic of water and ligands (2,4-pentandionyl anion, methylglyoxal, and acetate) were identified. To characterize the impact of the hydrophobic protein environment around the metal center on catalysis, a set of hydrophobic residues close to the active site were targeted. The variations resulted in an up to tenfold decrease of the O(2) reduction rates for the mutants. Molecular dynamics studies revealed an impact of the hydrophobic residues on the substrate stabilization in the active site as well as on the orientations of Glu98 and Arg80, which have previously been shown to be crucial for catalysis. Consequently, the Glu98-His104 interaction in the variants is weaker than in the wild-type complex. The role of protein structure in stabilizing the primary O(2) reduction step in Dke1 is discussed on the basis of our results.


Assuntos
Acinetobacter/enzimologia , Dioxigenases/química , Dioxigenases/metabolismo , Acinetobacter/química , Acinetobacter/genética , Sítios de Ligação , Dioxigenases/genética , Ligação de Hidrogênio , Ferro/química , Ferro/metabolismo , Simulação de Dinâmica Molecular , Mutação , Pentanonas/química , Pentanonas/metabolismo , Água/química , Água/metabolismo
16.
Radiat Prot Dosimetry ; 198(3): 129-138, 2022 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-35137234

RESUMO

This study aimed to determine the neutron dose equivalent to the thyroid gland and eye lens in brain tumor radiation therapy with 15- and 18-MV three-dimensional conformal methods (3D-CRT). A Monte Carlo simulation was performed using the Monte Carlo N-particle transport code to calculate neutron fluence and ambient dose equivalent (H*(10)). Afterward, these parameters were measured using a model NRD roentgen equivalent in man (REM) neutron detector (Thermo Electron Corporation, USA) equipped with Eberline's ASP-2e rate meter. Finally, the organ neutron dose equivalent was obtained by applying depth corrections to the measured ambient dose equivalent at the distance of the organ center from the central beam axis. The ratio of the out-of-field photon dose equivalent, measured previously, to the neutron dose equivalent in the eye lens was high due to its proximity to the radiation field. In contrast, this ratio remained unexpectedly high in the thyroid gland that is far from the central beam axis (about 15 cm). The calculated neutron parameters agreed with the measurements. The present study findings indicate that external field photon dose is the main source of thyroid gland biological effects in radiotherapy of brain tumors. In addition, it is appropriate to apply the model NRD REM neutron detector for measuring neutron contamination from high-energy linear accelerators inside and outside the treatment field.


Assuntos
Nêutrons , Aceleradores de Partículas , Boranos , Encéfalo , Humanos , Método de Monte Carlo , Fótons , Dosagem Radioterapêutica
17.
Homo ; 73(1): 49-60, 2022 Nov 09.
Artigo em Inglês | MEDLINE | ID: mdl-36218259

RESUMO

This paper presents the changes caused by macroabrasion of teeth on skeletal remains found in tomb No 4 in the west necropolis of the archeological site Kopila near Blato on the island of Korcula. The site archeologically dates back to the Late Iron Age, when the island was inhabited by the Illyrians. The aim of this study was to assess the dental age of the buried individuals at death and determine the type of their diet, which could give us a preliminary insight into the socio-economic standard of the inhabitants of the settlement. The analyzed sample is part of the collection of excavated skeletal remains kept in the Vela Luka Cultural Center on the island of Korcula. 284 permanent teeth, 19 fragments of the maxilla and 20 fragments of the mandible were found in the tomb, which were classified into 32 individuals and by sex. Teeth were analyzed by metric and non-metric methods of determining dental status in order to assess the dental age at the time of death and the diet of the inhabitants. The dental age of individuals was determined by the Lovejoy method and the degree of tooth wear by the Smith-Knight method. The analysis of the stable isotope 14C determined the exact time of death of the analyzed individuals. The tooth wear changes were very pronounced and present on 92.9% of teeth, equally on incisors and molars (p = 0.236). There is no significant gender difference (p > 0.05 for all teeth and jaw parts). There was no difference in the degree of tooth wear of the teeth of the mandible and maxilla (t = -0.266, p = 0.791), nor in the degree of tooth wear of the teeth of the maxilla right and left (t = -0.392, p = 0.702) or in the degree of tooth wear of the teeth of the mandible right and left (t = -0.889, p = 0.390). The average age of the analyzed population sample was 35.6 (±3.1) years. They were buried between 360-40 BC. Tooth wear changes observed on the analyzed teeth indicate a diet rich in hard, weakly cariogenic food with particles that were probably of inorganic origin, which caused an increased wear of tooth structures. The population was sedentary, agricultural type and the life expectancy was normal for the Late Iron Age. Besides, their socio-economic status was good. The age at the time of their death was between 30 and 40 years. Further studies should include more accurate and standardized methods for assessing the condition.


Assuntos
Restos Mortais , Desgaste dos Dentes , Humanos , Adulto , Croácia , Dieta , Incisivo
18.
Radiol Oncol ; 56(4): 541-551, 2022 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-36259318

RESUMO

BACKGROUND: The incidence of carcinoma during pregnancy is reported to be 1:1000-1:1500 pregnancies with the breast carcinoma being the most commonly diagnosed. Since the fetus is most sensitive to ionizing radiation during the first two trimesters, there are mixed clinical opinions and no uniform guidelines on the use of radiotherapy during pregnancy. Within this study the pregnant female phantom in the second trimester, that can be used for radiotherapy treatment planning (as DICOM data), Monte Carlo simulations (as voxelized geometry) and experimental dosimetry utilizing 3D printing of the molds (as .STL files), was developed. MATERIALS AND METHODS: The developed phantom is based on MRI images of a female patient in her 18th week of pregnancy and CT images after childbirth. Phantom was developed in such a manner that a pregnant female was scanned "in vivo" using MRI during pregnancy and CT after childbirth. For the treatment of left breast carcinoma, 3D conformal radiotherapy was used. The voxelized geometry of the phantom was used for Monte Carlo (MC) simulations using Monte Carlo N-Particle transport codeTM 6.2 (MCNP). CONCLUSIONS: The modeled photon breast radiotherapy plan, applied to the phantom, indicated that the fetus dose is 59 mGy for 50 Gy prescribed to the breast. The results clearly indicate that only 9.5% of the fetal dose is caused by photons that are generated in the accelerator head through scattering and leakage, but the dominant component is scattered radiation from the patient's body.


Assuntos
Neoplasias da Mama , Fótons , Humanos , Gravidez , Feminino , Imagens de Fantasmas , Método de Monte Carlo , Fótons/uso terapêutico , Radiometria/métodos , Neoplasias da Mama/diagnóstico por imagem , Neoplasias da Mama/radioterapia
19.
Int J Legal Med ; 125(2): 315-21, 2011 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-20878416

RESUMO

The aim of this cross-sectional study was to compare the accuracy of the Cameriere European formula (Cameriere), adopted Haavikko method from 1974 (Haavikko), and revisited Demirjian method by Willems (Willems) for age estimation on orthopantomograms (OPGs) of Bosnian-Herzegovian (BH) children age groups 6-13 years. The accuracy was determined as difference between estimated dental age (DA) and chronological age (CA) and the absolute accuracy (absolute difference) was assessed by analyzing OPGs of 591 girls and 498 boys. The Cameriere method overestimated the mean age by 0.09 year for girls and underestimated by -0.02 year for boys. The Haavikko method underestimated the mean age by -0.29 year for girls and -0.09 year for boys. The Willems method overestimated the mean age by 0.24 year in girls and by 0.42 year in boys. The absolute accuracies were 0.53 year for girls and 0.55 year for boys for Cameriere method; for Haavikko method, 0.59 year for girls and 0.62 year for boys; and for Willems method 0.69 year for girls and 0.67 year for boys. In conclusion, Cameriere method is the most accurate for estimating the age of BH children age groups 6-13 years using OPGs, following adopted Haavikko method and Willems method.


Assuntos
Determinação da Idade pelos Dentes/métodos , Adolescente , Bósnia e Herzegóvina , Criança , Dermatite de Contato , Feminino , Odontologia Legal , Humanos , Masculino , Radiografia Panorâmica
20.
Coll Antropol ; 35(2): 353-7, 2011 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21755702

RESUMO

Dental age estimation is common in orthodontics, paedodontics, paleodontology and forensic dentistry. The aim of this study was to assess chronological course of eruptive developmental phases of third molar and to establish parameters for the Croatian population. Sample of this study consisted of 1249 orthopantomograms of 530 (42.4%) male and 719 (57.6%) female subjects, aged 10 to 25 years. Eruptive phases were classified in 4 stages. No significant sex difference was found. Established chronology of the third molar eruption can be used as a standard for the assessment of dental age in clinical and forensic research on samples of Croatian population.


Assuntos
Determinação da Idade pelos Dentes/métodos , Dente Serotino/crescimento & desenvolvimento , Erupção Dentária , Adolescente , Adulto , Criança , Croácia/epidemiologia , Feminino , Odontologia Legal , Humanos , Masculino , Dente Serotino/diagnóstico por imagem , Radiografia Panorâmica , Estatísticas não Paramétricas
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