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1.
Radiat Res ; 199(6): 583-590, 2023 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-37057978

RESUMO

Translocation analysis using fluorescence in situ hybridization (FISH) is the method of choice for dose assessment in case of chronic or past exposures to ionizing radiation. Although it is a widespread technique, unlike dicentrics, the number of FISH-based inter-laboratory comparisons is small. For this reason, although the current Running the European Network of Biological and Physical retrospective Dosimetry (RENEB) inter-laboratory comparison 2021 was designed as a fast response to a real emergency scenario, it was considered a good opportunity to perform an inter-laboratory comparison using the FISH technique to gain further experience. The Bundeswehr Institute of Radiobiology provided peripheral blood samples from one healthy human volunteer. Three test samples were irradiated with blinded doses of 0, 1.2, and 3.5 Gy, respectively. Samples were then sent to the seven participating laboratories. The FISH technique was applied according to the standard procedure of each laboratory. Both, the frequency of translocations and the estimated dose for each sample were sent to the coordinator using a special scoring sheet for FISH. All participants sent their results in due time. However, although it was initially requested to send the results based on the full analysis, evaluating 500 equivalent cells, most laboratories only sent the results based on triage, with a smaller number of analyzed cells. In the triage analysis, there was great heterogeneity in the number of equivalent cells scored. On the contrary, for the full analysis, this number was more homogeneous. For all three samples, one laboratory showed outlier yields compared to the other laboratories. Excluding these results, in the triage analysis, the frequency of translocations in sample no. 1 ranged from 0 to 0.013 translocations per cell, and for samples no. 2 and no. 3 the genomic mean frequency were 0.27 ± 0.03 and 1.47 ± 0.14, with a coefficient of variation of 0.29 and 0.23 respectively. Considering only results obtained in the triage analysis for sample no. 1, all laboratories, except one, classified this sample as the non-irradiated one. For sample no. 2, excluding the outlier value, the mean reported dose was 1.74 ± 0.16 Gy indicating a mean deviation of about 0.5 Gy to the delivered dose of 1.2 Gy. For sample no. 3 the mean dose estimated was 4.21 ± 0.21 Gy indicating a mean deviation of about 0.7 Gy to the delivered dose of 3.5 Gy. In the frame of RENEB, this is the second FISH-based inter-laboratory comparison. The whole exercise was planned as a response to an emergency, therefore, a triage analysis was requested for all the biomarkers except for FISH. Although a full analysis was initially requested for FISH, most of the laboratories reported only a triage-based result. The main reason is that it was not clearly stated what was required before starting the exercise. Results show that most of the laboratories successfully discriminated unexposed and irradiated samples from each other without any overlap. A good agreement in the observed frequencies of translocations was observed but there was a tendency to overestimate the delivered doses. Efforts to improve the harmonization of this technique and subsequent exercises to elucidate the reason for this trend should be promoted.


Assuntos
Radiometria , Translocação Genética , Humanos , Hibridização in Situ Fluorescente/métodos , Estudos Retrospectivos , Radiometria/métodos , Bioensaio/métodos , Aberrações Cromossômicas
2.
Urol Case Rep ; 35: 101554, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33437647

RESUMO

Retroperitoneal primitive neuroectodermal tumors (PNET) is a rare neoplastic disease of high malignancy with a tendency towards early metastasis, affect young adults irrespective of the gender. We present 81 year old woman, who was admitted in the Urology Department with symptoms of right flank pain and hematuria. Contrast-enhanced computerized tomography scan (CT-scan) showed a large heterogeneous right kidney mass around 12 cm in diameter. The final diagnosis of primitive neuroectodermal tumor (PNET) was established based on clinical, pathological, and molecular results.

3.
Urol Case Rep ; 28: 101064, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31754603

RESUMO

We report 1 case of Benign Leydig cell tumor. A 45-year-old male was admitted to the Urology department with a large painless mass in the right testis of 1 year duration. The patient underwent radical high right orchiectomy, with a preliminary diagnosis of right testicular tumor. On the basis of the pathologic and immunohistochemical findings, the testicular mass was diagnosed as a benign Leydig cell tumor. Long-term follow-up is necessary to exclude recurrence or metastasis and also the endocrine profile and imaging investigations need to be repeated periodically.

4.
Environ Pollut ; 223: 595-604, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-28153413

RESUMO

An exposure assessment for multiple pharmaceuticals in Swedish surface waters was made using the STREAM-EU model. Results indicate that Metformin (27 ton/y), Paracetamol (6.9 ton/y) and Ibuprofen (2.33 ton/y) were the drugs with higher amounts reaching the Baltic Sea in 2011. 35 of the studied substances had more than 1 kg/y of predicted flush to the sea. Exposure potential given by the ratio amount of the drug exported to the sea/amount emitted to the environment was higher than 50% for 7 drugs (Piperacillin, Lorazepam, Metformin, Hydroxycarbamide, Hydrochlorothiazide, Furosemide and Cetirizine), implying that a high proportion of them will reach the sea, and below 10% for 27 drugs, implying high catchment attenuation. Exposure potentials were found to be dependent of persistency and hydrophobicity of the drugs. Chemicals with Log D > 2 had exposure potentials <10% regardless of their persistence. Chemicals with Log D  <  -2 had exposure potentials >35% with higher ratios typically achieved for longer half-lives. For Stockholm urban area, 17 of the 54 pharmaceuticals studied had calculated concentrations higher than 10 ng/L. Model agreement with monitored values had an r2 = 0.62 for predicted concentrations and an r2 = 0.95 for predicted disposed amounts to sea.


Assuntos
Monitoramento Ambiental , Modelos Teóricos , Oceanos e Mares , Preparações Farmacêuticas/análise , Água do Mar/química , Poluentes Químicos da Água/análise , Recursos Hídricos , Exposição Ambiental/análise , Suécia
5.
Sci Total Environ ; 572: 508-519, 2016 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-27552129

RESUMO

An emissions inventory for top consumed human pharmaceuticals in Sweden was done based on national consumption data, human metabolic rates and wastewater treatment removal rates. Concentrations of pharmaceuticals in surface waters in Swedish river basins were predicted using estimated emissions from the inventory and river discharges. Our findings indicate that the top ten emitted pharmaceuticals in our study set of 54 substances are all emitted in amounts above 0.5ton/y to both surface waters and soils. The highest emissions to water were in decreasing order for Metformin, Furosemide, Gabapentin, Atenolol and Tramadol. Predicted emissions to soils calculated with the knowledge that in Sweden sludge is mostly disposed to soil, point to the highest emissions among the studied drugs coming from, in decreasing order, Metformin, Paracetamol, Ibuprofen, Gabapentin and Atenolol. Surface water concentrations in Sweden's largest rivers, all located in low density population zones, were found to be below 10ng/L for all substances studied. In contrast, concentrations in surface waters in Stockholm's metropolitan area, the most populous in Sweden, surpassed 100ng/L for four substances: Atenolol, Metformin, Furosemide and Gabapentin.


Assuntos
Monitoramento Ambiental , Preparações Farmacêuticas/análise , Rios/química , Águas Residuárias/análise , Poluentes Químicos da Água/análise , Humanos , Suécia
6.
Prilozi ; 33(1): 209-16, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22952106

RESUMO

UNLABELLED: The aim of this study is to show the importance of ultrasound method in the diagnosis of Achilles tendon rupture, the choice of method of treatment and monitoring of treatment using the same method. MATERIAL AND METHODS: Between 1999 and 2009, 134 patients with Achilles tendon rupture were referred to our Clinic. 66 patients (with a mean age of 38 years) were treated with surgical suture followed by plaster immobilization for a period of 8 weeks. 68 patients (with a mean age of 42 years) were treated conservatively with plaster immobilization for a period of 8 weeks. The follow-up in both groups of patients was 2 years. RESULTS: During the clinical and ultrasound monitoring of the patients it was proved that repeated rupture of the same tendon occurs on average within 12 months. Return to sports activities showed in 57% of the conservatively treated patients and in 55% of surgically treated patients. The patients with Achilles tendon rupture were treated at our Clinic with previously standardized protocol which, besides the clinical examination, used the ultrasound method. SUMMARY: Ultrasound examination is a very important method in the diagnosis and the choice of the method of treatment, as well as in the evaluation of results in patients with Achilles tendon rupture, either in operative or conservative treatment.


Assuntos
Tendão do Calcâneo/diagnóstico por imagem , Tendão do Calcâneo/lesões , Traumatismos dos Tendões/diagnóstico por imagem , Traumatismos dos Tendões/terapia , Adulto , Feminino , Humanos , Masculino , Procedimentos Ortopédicos , Ruptura/diagnóstico por imagem , Ruptura/terapia , Ultrassonografia
7.
SAR QSAR Environ Res ; 23(1-2): 17-36, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22014234

RESUMO

The new development of the bioconcentration factor (BCF) base-line model of Dimitrov et al. [SAR QSAR Environ. Res. 6 (2005), pp. 531-554] is presented. The model applicability domain was expanded by enlarging the training set of the model up to 705 chemicals. The list of chemical-dependent mitigating factors was expanded by including water solubility of chemicals. The original empirical term for estimating ionization of chemicals was mechanistically analysed using two different approaches. In the first one, the ionization potential of chemicals was estimated based on the acid dissociation constant (pK(a) ). This term was found to be less adequate for inclusion in the ultimate BCF model, due to overestimating ionization of chemicals. The second approach, estimating the ionization as a ratio between distribution and partition coefficients (log P and log D), was found to be more successful. The new ionization term allows modelling of chemicals with both acidic and basic functionalities and chemicals undergoing different degrees of ionization. The significance of the different mitigating factors which can reduce the maximum bioconcentration potential of the chemicals was re-formulated and model parameters re-evaluated.


Assuntos
Fenômenos Químicos , Poluentes Ambientais/metabolismo , Modelos Teóricos , Absorção , Animais , Íons/química , Análise dos Mínimos Quadrados , Metabolismo , Modelos Estatísticos , Relação Quantitativa Estrutura-Atividade , Solubilidade , Água
8.
Prilozi ; 33(2): 153-61, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-23425878

RESUMO

UNLABELLED: The aim of this paper is to present the importance of orthopaedics in the prevention, treatment and rehabilitation of persons with cerebral palsy. MATERIAL AND METHODS: The paper is based on a study realized at the University Orthopaedic Clinic, Medical School, Ss. Cyril and Methodius University in Skopje, with application of documentary analysis, observation and clinical analysis of 76 patients with cerebral palsy, aged between 1 and 15 years. RESULTS: Orthopaedics is a surgical field of medicine, in which context there have been, are and will be, as a challenge, many questions for the present and future generations. Data analysis pointed out that surgical treatment in combination with conservative treatment give a hope that a definite or prolonged cure is possible, with maximal and possibly preserved function of the loco-motor system or, in the most serious cases, abatement of the impaired locomotor system symptoms. SUMMARY: Early diagnosis and appropriate application of surgical treatment enable better functioning of persons with cerebral palsy by maximal exploitation of their remaining abilities.


Assuntos
Paralisia Cerebral/prevenção & controle , Paralisia Cerebral/terapia , Procedimentos Ortopédicos , Adolescente , Paralisia Cerebral/reabilitação , Criança , Pré-Escolar , Diagnóstico Precoce , Feminino , Humanos , Lactente , Masculino , Resultado do Tratamento
9.
SAR QSAR Environ Res ; 22(7-8): 719-55, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-21999837

RESUMO

The unprecedented pollution of the environment by xenobiotic compounds has provoked the need to understand the biodegradation potential of chemicals. Mechanistic understanding of microbial degradation is a premise for adequate modelling of the environmental fate of chemicals. The aim of the present paper is to describe abiotic and biotic models implemented in CATALOGIC software. A brief overview of the specificities of abiotic and microbial degradation is provided followed by detailed descriptions of models built in our laboratory during the last decade. These are principally new models based on unique mathematical formalism already described in the first paper of this series, which accounts more adequately than currently available approaches the multipathway metabolic logic in prokaryotes. Based on simulated pathways of degradation, the models are able to predict quantities of transformation products, biological oxygen demand (BOD), carbon dioxide (CO(2)) production, and primary and ultimate half-lives. Interpretation of the applicability domain of models is also discussed.


Assuntos
Biotransformação , Simulação por Computador , Poluentes Ambientais/metabolismo , Poluentes Ambientais/toxicidade , Xenobióticos/metabolismo , Xenobióticos/toxicidade , Análise da Demanda Biológica de Oxigênio , Dióxido de Carbono/metabolismo , Poluentes Ambientais/química , Redes e Vias Metabólicas , Medição de Risco/métodos , Software , Xenobióticos/química
10.
Prilozi ; 32(1): 189-97, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21822187

RESUMO

The aim of the present paper is to evaluate the importance of clinical examination in the process of diagnosing meniscal lesions, as well as to establish the accuracy of clinical examination in comparison to the arthroscopic diagnosis. In the last 5 years, in the Orthopedic Surgery Clinic in Skopje, the authors have diagnosed and treated 205 patients suffering from meniscal lesions. The method of anamnestic testing, and of clinical examination and the statistical method have been applied. All the patients were subjected to the following tests: well taken anamnesis of the knee injury mechanism, standard orthopedic examination (Stainman I and II, McMurray and Appley test), standard radiographic images of the knee, additional examination with MRI for some of the patients and arthroscopic examination. The results obtained with clinically established diagnosis were compared to the results obtained with arthroscopic diagnosis. Comparing the results of the clinical and arthroscopic diagnoses, an insufficiency of the clinical diagnosis of almost 20% was established. The results are close to those given in the professional literature which refers to the standardized approach in taking the anamnestic data and the realization of the physical signs and tests examination technique. It means that the physical signs and tests, as well as the well-taken anamnesis, are the foundation for establishing a diagnosis of meniscal lesions. Arthroscopy is truly the only golden standard for the diagnosis of all entities of the knee joint, including meniscal lesions.


Assuntos
Artroscopia/métodos , Traumatismos do Joelho/diagnóstico , Lesões do Menisco Tibial , Adulto , Artrografia/métodos , Precisão da Medição Dimensional , Feminino , Humanos , Imageamento por Ressonância Magnética/métodos , Masculino , Exame Físico/métodos , Reprodutibilidade dos Testes , Estudos Retrospectivos , Sensibilidade e Especificidade
11.
Prilozi ; 32(1): 199-209, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21822188

RESUMO

UNLABELLED: The aim of this study is to make a correlation of the clinical and radiographic results after performing two different surgical procedures for correction of hallux valgus deformity. MATERIAL AND METHODS: The study included 70 patients having hallux valgus deformity of the foot, and they were divided into two groups. The first group (Group 1) was composed of 35 patients who were treated by osteotomy of the I-st metatarsal bone according to Mitchell, while the second group (Group 2) was also composed of 35 patients who were treated by resectional arthroplasty according to Keller. Clinical (pain and metatarsalgia, as well as most dominant symptoms) and radiographic examinations (I metatarsophalangeal angle and I intermetatarsal angle) were analysed comparatively during the evaluation. The analysis of the clinical and radiographic results was performed pre-operatively and post-operatively for the two groups. RESULTS: According to their sex, the patients were 5 men and 65 women. Using the method of Mitchell, pain as a clinical symptom post-operatively was found in only 3 patients out of the 35 with operated feet, while in the other group of patients treated by the method of Keller, there was no presence of pain in any of the patients. Comparatively, this does not present a statistically significant difference (p>0.05). Nor do, the differences in the distribution of metatrsalgia incidence show a statistical significance between the two groups (p>0.05). There is no significant difference (p>0.05) in the patients of the two groups concerning the pre-operative mean dimension values of the I metatarsophalangeal angle and I intermetatarsal angle. However, the radiographic analysis of the same angles in both groups, one year post-operatively, showed a high statistically significant difference (p<0.001). SUMMARY: Mitchell's operative technique could be recommended as an effective procedure for the correction of hallux valgus and metatarsus primus varus in young and middle-aged patients, while the resection arthroplasty according to the method of Keller is recommended for older patients with arthrotic changes.


Assuntos
Artroplastia , Hallux Valgus , Articulação Metatarsofalângica , Osteotomia , Adulto , Artralgia/diagnóstico por imagem , Artralgia/etiologia , Artroplastia/efeitos adversos , Artroplastia/métodos , Pesquisa Comparativa da Efetividade , Feminino , Hallux Valgus/diagnóstico , Hallux Valgus/cirurgia , Humanos , Masculino , Articulação Metatarsofalângica/diagnóstico por imagem , Articulação Metatarsofalângica/cirurgia , Pessoa de Meia-Idade , Osteotomia/efeitos adversos , Osteotomia/métodos , Avaliação de Processos e Resultados em Cuidados de Saúde , Complicações Pós-Operatórias , Radiografia , República da Macedônia do Norte
12.
Toxicon ; 56(6): 897-913, 2010 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-20600223

RESUMO

The venom of Antarctic octopus remains completely unstudied. Here, a preliminary investigation was conducted into the properties of posterior salivary gland (PSG) extracts from four Antarctica eledonine (Incirrata; Octopodidae) species (Adelieledone polymorpha, Megaleledone setebos, Pareledone aequipapillae, and Pareledone turqueti) collected from the coast off George V's Land, Antarctica. Specimens were assayed for alkaline phosphatase (ALP), acetylcholinesterase (AChE), proteolytic, phospholipase A(2) (PLA(2)), and haemolytic activities. For comparison, stomach tissue from Cirroctopus sp. (Cirrata; Cirroctopodidae) was also assayed for ALP, AChE, proteolytic and haemolytic activities. Dietary and morphological data were collected from the literature to explore the ecological importance of venom, taking an adaptive evolutionary approach. Of the incirrate species, three showed activities in all assays, while P. turqueti did not exhibit any haemolytic activity. There was evidence for cold-adaptation of ALP in all incirrates, while proteolytic activity in all except P. turqueti. Cirroctopus sp. stomach tissue extract showed ALP, AChE and some proteolytic activity. It was concluded that the AChE activity seen in the PSG extracts was possibly due to a release of household proteins, and not one of the secreted salivary toxins. Although venom undoubtedly plays an important part in prey capture and processing by Antarctica eledonines, no obvious adaptations to differences in diet or morphology were apparent from the enzymatic and haemolytic assays. However, several morphological features including enlarged PSG, small buccal mass, and small beak suggest such adaptations are present. Future studies should be conducted on several levels: Venomic, providing more detailed information on the venom compositions as well as the venom components themselves; ecological, for example application of serological or genetic methods in identifying stomach contents; and behavioural, including observations on capture of different types of prey.


Assuntos
Adaptação Fisiológica , Temperatura Baixa , Meio Ambiente , Venenos de Moluscos/análise , Octopodiformes/fisiologia , Fosfatase Alcalina/metabolismo , Animais , Regiões Antárticas , Inibidores da Colinesterase/metabolismo , Eritrócitos/efeitos dos fármacos , Feminino , Hemólise , Masculino , Venenos de Moluscos/enzimologia , Venenos de Moluscos/farmacologia , Octopodiformes/anatomia & histologia , Octopodiformes/classificação , Fenótipo , Filogenia , Glândulas Salivares/química , Glândulas Salivares/metabolismo
13.
Sci Total Environ ; 408(18): 3787-93, 2010 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-20185163

RESUMO

Mechanistic understanding of bioaccumulation in different organisms and environments should take into account the influence of organism and chemical depending factors on the uptake and elimination kinetics of chemicals. Lipophilicity, metabolism, sorption (bioavailability) and biodegradation of chemicals are among the important factors that may significantly affect the bioaccumulation process in soil organisms. This study attempts to model elimination kinetics of organic chemicals in earthworms by accounting for the effects of both chemical and biological properties, including metabolism. The modeling approach that has been developed is based on the concept for simulating metabolism used in the BCF base-line model developed for predicting bioaccumulation in fish. Metabolism was explicitly accounted for by making use of the TIMES engine for simulation of metabolism and a set of principal transformations. Kinetic characteristics of transformations were estimated on the basis of observed kinetics data for the elimination of organic chemicals from earthworms.


Assuntos
Modelos Químicos , Oligoquetos/metabolismo , Compostos Orgânicos/metabolismo , Poluentes do Solo/metabolismo , Animais , Cinética , Compostos Orgânicos/química , Hidrocarbonetos Policíclicos Aromáticos/química , Hidrocarbonetos Policíclicos Aromáticos/metabolismo , Poluentes do Solo/química
14.
Vet Parasitol ; 123(3-4): 179-88, 2004 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-15325044

RESUMO

Trichinella spp. larvae were collected from domestic and wild-life animals in association with 15 human trichinellosis outbreaks registered between 1999-2002 in Bulgaria. Furthermore, Trichinella spp. isolates were obtained from 62 naturally infected wild animals and of a rat. All isolates were subjected to speciation by both multiplex PCR and cross-breeding experiments. Epidemiological and clinical data were collected and analysed using standard protocols for epidemiological surveillance and control of outbreaks. Only two species were identified-Trichinella britovi and Trichinella spiralis. Results obtained by molecular typing fully matched those of cross-breeding. More specifically, parasite isolates obtained upon 15 epidemic outbreaks revealed the predominance of T. britovi (n = 10) when compared to T. spiralis (n = 5). With regard to host origin, the predominant species detected among wild boar was T. britovi (n = 4), and T. spiralis was identified in one wild boar sample only. Among the isolates obtained from domestic pig products, T. britovi was found in five cases and T. spiralis in four cases, respectively. In the naturally infected wild animals not related to epidemics, only T. britovi was demonstrated. The present results provide a strong indication that both T. britovi and T. spiralis operate within domestic and sylvatic cycles in Bulgaria. Geographically, the distribution of T. britovi appears to include Central, Southern, Eastern and Western parts of the country, and wildlife animals from the Mid Balkan Mountains and Mid Sredna Gora Mountains, T. spiralis was found in Western and Southwestern Bulgaria, only.


Assuntos
Surtos de Doenças , Doenças dos Suínos/parasitologia , Trichinella spiralis/classificação , Triquinelose/parasitologia , Triquinelose/veterinária , Zoonoses/parasitologia , Animais , Bulgária/epidemiologia , Carnívoros , DNA de Helmintos/química , DNA de Helmintos/genética , Parasitologia de Alimentos , Genótipo , Humanos , Carne/parasitologia , Reação em Cadeia da Polimerase/veterinária , Ratos , Suínos , Doenças dos Suínos/epidemiologia , Trichinella spiralis/genética , Trichinella spiralis/crescimento & desenvolvimento , Trichinella spiralis/isolamento & purificação , Triquinelose/epidemiologia
15.
Z Naturforsch C J Biosci ; 56(9-10): 843-7, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11724393

RESUMO

The active site of Viviparus ater (mollusc) hemocyanin was investigated using the fact that the binding of dioxygen to the binuclear copper-containing sites of hemocyanins is connected with the appearance of specific dichroic bands which are very sensitive to changes in the structrure and polarity of the environment. Oxy-Viviparus ater hemocyanin exhibits near UV and visible circular dichroism spectra different from those of other molluscan and arthropodan hemocyanins. These differences are due probably to variations in the geometry or charge distribution in the dioxygen binding sites of the compared proteins. The thermostability of Viviparus ater hemocyanin and the significance of the copper-dioxygen system for the stability were also investigated. "Melting" temperatures, Tm, of 77 degrees C for the oxy-hemocyanin and 57 degrees C for the apo-protein were calculated from the denaturation curves which demonstrates the considerable role of the binuclear active site for the thermostability. Viviparus ater hemocyanin is more thermostable than other hemocyanins for which data are published.


Assuntos
Hemocianinas/metabolismo , Moluscos/fisiologia , Oxigênio/metabolismo , Aminoácidos/análise , Animais , Apoproteínas/química , Apoproteínas/metabolismo , Sítios de Ligação , Dicroísmo Circular , Estabilidade de Medicamentos , Hemocianinas/química , Oxigênio/química , Conformação Proteica , Espectrofotometria
16.
Curr Microbiol ; 42(5): 368-71, 2001 May.
Artigo em Inglês | MEDLINE | ID: mdl-11400059

RESUMO

Esperase is a highly alkalophilic bacterial proteinase produced by Bacillus lentus. The enzyme hydrolyzes peptide bonds comprising the carboxylic groups of hydrophobic as well as hydrophilic residues in the oxidized insulin B chain. Some of these bonds are not attacked by other alkaline microbial proteinases. P1-P4 specificity was determined by a series of peptide nitroanilides. The S1 recognition loop exhibits a preference for Phe. The "cleft" of the smallest subsite S2 prefers Ala and exhibits low affinity for the larger chain of Leu. S3 is more open than the other subsites and can accept a variety of residues. Hydrophobic interactions predominate in the S4-P4 interactions because S4 can accommodate Phe very well. The results characterize Esperase as an endopeptidase with a broader specificity in comparison with other microbial serine proteinases. This is probably owing to a more flexible substrate binding site.


Assuntos
Anilidas/metabolismo , Bacillus/enzimologia , Insulina/metabolismo , Serina Endopeptidases/química , Serina Endopeptidases/metabolismo , Sítios de Ligação , Cristalografia por Raios X , Insulina/química , Especificidade por Substrato
17.
Z Naturforsch C J Biosci ; 56(5-6): 416-22, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11421459

RESUMO

Penaeus monodon (class Crustacea, order Decapoda) is one of the largest shrimps of the Penaeidea family from the Indo-West Pacific region. The dioxygen-transporting protein hemocyanin, isolated from the hemolymph of this invertebrate, is composed of three 75-76 kDa structural/functional subunits designated as Pm1, Pm2 and Pm3. The N-terminal sequences of the chains were determined and compared with those of other decapodan hemocyanin subunits. Pm2 and Pm3 are highly homologous and electrophoretically undistinguishable polypeptides. In comparison to Pml, they have an extension of six residues. Pm1 is closely related to the subunit Pv2 of the Penaeus vannamei hemocyanin. Probably, subunits like Pm1 and Pv2 are family-specific for the Penaeidea hemocyanins and the other subunits are species-specific. Comparison of N-terminal sequences of respiratory proteins from the sub-orders Natantia and Reptantia demonstrated family- and sub-order-specific sequences. A melting point of 69 degrees C, lower than those for the di-hexameric decapodan hemocyanins, was determined from the temperature dependence of ellipticity of the mono-hexameric Penaeus monodon hemocyanin. Thermostability of decapodan hemocyanins depends on their aggregation state.


Assuntos
Crustáceos , Hemocianinas/química , Penaeidae , Sequência de Aminoácidos , Animais , Hemocianinas/isolamento & purificação , Dados de Sequência Molecular , Desnaturação Proteica , Subunidades Proteicas , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos , Termodinâmica
18.
Arch Biochem Biophys ; 387(2): 197-201, 2001 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-11370841

RESUMO

Savinase and Esperase are closely related highly alkalophilic proteinases produced by Bacillus lentus. They are suitable couple for investigating the structural basis of proteinase specificity due to the identity of the catalytic and the differences in the substrate binding sites. Two of the substitutions in these sites are very important: T129P and G131P. The two prolines provide an extra rigidity of the Savinase-binding site. The substitutions S166N and Q191T in the S1 recognition loop change the binding geometry of the substrate P1 residue. The geometry of S1 in Esperase is more favorable for binding and catalysis in comparison to that in Savinase. Differences in P3 specificity are probably created by the substitution V104L, which influences the conformation of S3. Leu in position 104 is more favorable for the binding of Phe to S4 than Val. The lower affinity and catalytic efficiency as well as more narrow proteolytic specificity of Savinase in comparison to those of Esperase are explained with the extra rigidity and unfavorable changes in geometry of the substrate binding site of the first enzyme.


Assuntos
Serina Endopeptidases/química , Álcalis , Substituição de Aminoácidos/fisiologia , Compostos de Anilina/química , Bacillus , Sítios de Ligação/fisiologia , Catálise , Simulação por Computador , Endopeptidases , Insulina/química , Modelos Moleculares , Oxirredução , Peptídeos/química , Subunidades Proteicas , Relação Estrutura-Atividade , Especificidade por Substrato/fisiologia
19.
Curr Microbiol ; 41(1): 70-2, 2000 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-10919403

RESUMO

The proteolytic specificity of the neutral Zn-dependent proteinase from Thermoactinomyces sacchari was determined by analysis of the peptides obtained after incubation with the oxidized insulin B chain as a substrate. The enzyme is an endopeptidase with broad specificity. In total, 12 peptide bonds in the B chain of insulin were hydrolyzed. The major requirement is that a hydrophobic residue such as Leu, Val, or Phe should participate with the alpha-amino group in the bond to be cleaved. However, hydrolysis of bonds at the N-terminal side of His, Thr, and Gly was also observed. The peptide bond Leu 15-Tyr 16 in the oxidized insulin B chain, which is the major cleavage site for the alkaline microbial proteinases, is resistant to the attacks of the enzyme from Thermoactinomyces sacchari and other neutral proteinases. The proteolytic activity of the Zn-dependent proteinase from T sacchari is different from those of other metalloendopeptidases from microorganisms.


Assuntos
Insulina/metabolismo , Metaloendopeptidases/metabolismo , Micromonosporaceae/enzimologia , Zinco/metabolismo , Sequência de Aminoácidos , Aminoácidos/química , Insulina/química , Metaloendopeptidases/química , Micromonosporaceae/metabolismo , Dados de Sequência Molecular , Oxirredução , Fragmentos de Peptídeos/química , Especificidade por Substrato , Zinco/química
20.
Spectrochim Acta A Mol Biomol Spectrosc ; 56(14): 2811-6, 2000 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11145348

RESUMO

Vipoxin is a neurotoxin from the venom of Vipera ammodytes meridionalis, the most toxic snake in Europe. It is a unique complex of a toxic phospholipase A2 (PLA2) and a non-toxic PLA2-like protein inhibitor (Inh) which probably evolved from the enzyme and reduces its activity and toxicity. The enzymatic activity of Vipoxin is Ca2+-dependent and the interaction of this metal ion with the neurotoxic complex and its separated components was investigated using the fluorescent probe ANS. Vipoxin binds two calcium ions, one per each subunit. The X-ray model of the Ca2+-free neurotoxin shows that the potential metal-binding sites require minor structural changes to bind calcium. The dissociation constants K(2+)Ca of the calcium complexes of Vipoxin and its components, PLA2 and Inh, were determined to be 16, 10 and 9 mM, respectively. The affinity for calcium of Vipoxin is reduced in comparison to those of PLA2 and Inh. The X-ray model shows that the potential Ca2+-binding sites in the two components are partially 'shielded' in the complex. The affinity of the neurotoxin to Sr2+ and Ba2+ is lower and the respective K(2+)Ca are 20 and 30 mM. The saturation of Ca2+-binding sites increased the melting point Tm of Vipoxin by 11 degrees C and the activation energy for the thermal deactivation of the excited tryptophans Ea by 11 kJ mol(-1) x Ca2+ is important not only for the enzymatic activity of Vipoxin but also for its thermostability.


Assuntos
Cálcio/metabolismo , Venenos de Víboras/química , Animais , Sítios de Ligação , Cálcio/química , Cristalografia por Raios X , Modelos Moleculares , Conformação Proteica , Espectrometria de Fluorescência , Viperidae
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