Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 42
Filter
1.
J Equine Vet Sci ; 138: 105099, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38763365

ABSTRACT

The reproductive features of equine leptospirosis are often neglected. Equine genital leptospirosis is characterized as a silent chronic syndrome, and besides abortions, leads to placental abnormalities, stillbirths, and birth of weak foals. This study aimed to study the occurrence of placental abnormalities associated with Leptospira interrogans infection in naturally infected mares under field conditions. The studied herd had a high occurrence of placentitis and abortions. Ten pregnant mares, eight with placental abnormalities on ultrasonography and were selected. Serum and cervicovaginal mucus (CVM) samples were collected for serology and PCR, respectively. Positive samples in lipL32-PCR were submitted to the sequencing of the secY gene. In lipL32-PCR of CVM, five out of 10 (50%) mares were positive and all were characterized as Leptospira interrogans. Our results highlight the presence of placental abnormalities in the reproductive subclinical leptospirosis syndrome. We encourage field veterinarians to include leptospirosis testing in their reproductive management.


Subject(s)
Horse Diseases , Leptospira interrogans , Leptospirosis , Placenta Diseases , Placenta , Pregnancy Complications, Infectious , Animals , Horses , Leptospirosis/veterinary , Leptospirosis/microbiology , Leptospirosis/epidemiology , Leptospirosis/complications , Horse Diseases/microbiology , Pregnancy , Female , Leptospira interrogans/isolation & purification , Placenta Diseases/microbiology , Placenta Diseases/veterinary , Placenta Diseases/pathology , Pregnancy Complications, Infectious/veterinary , Pregnancy Complications, Infectious/microbiology , Placenta/microbiology , Placenta/pathology
2.
Theriogenology ; 141: 128-133, 2020 Jan 01.
Article in English | MEDLINE | ID: mdl-31539641

ABSTRACT

The objective of this experiment was to determine if circulating concentrations of pregnancy associated glycoproteins (PAG) on day 24 of gestation can be utilized to diagnose pregnancy and embryo viability in beef cattle. Postpartum beef cows (n = 677) and heifers (n = 127) were exposed to a 7-day CO-Synch + CIDR estrus synchronization protocol followed by fixed-time AI (FTAI) on day 0. Blood samples were collected at day 24 after TAI to assess circulating concentrations of PAG utilizing an in-house ELISA. Pregnancy diagnosis was performed 30 and 100 days after FTAI via transrectal ultrasonography. Mean circulating PAG concentration at day 24 differed (P < 0.001) between animals diagnosed pregnant and non-pregnant at day 30 (1.69 ±â€¯0.10 ng/mL vs 0.30 ng/mL ±â€¯0.07 ng/mL; mean ±â€¯SEM; respectively). Pregnant heifers had increased PAG concentration at day 24 compared with pregnant cows (P < 0.01; 3.29 ±â€¯0.36 ng/mL vs 1.39 ±â€¯0.10 ng/mL, respectively). Based on receiver operating characteristic (ROC) curve analysis, serum concentration of PAG at day 24 ≥ 0.33 ng/mL in cows and ≥0.54 ng/mL in heifers was 95% accurate at determining pregnancy status at day 30. Heifers that experienced late embryonic mortality between day 30 and 100 of gestation had decreased circulating concentrations of PAG on day 24 (2.02 ng/mL ±â€¯0.73) compared with heifers that maintained an embryo until day 100 (3.69 ng/mL ±â€¯0.39; P = 0.02). However, there was no difference in day 24 PAG concentration (P = 0.39) between cows that maintained or lost a pregnancy (1.31 ng/mL ±â€¯0.25 vs 0.92 ng/ml ±â€¯0.50). In summary, circulating PAG concentration on day 24 of gestation may be a useful marker for early pregnancy detection in beef cattle, and might be a potential marker for predicting embryonic loss.


Subject(s)
Abortion, Veterinary/diagnosis , Cattle Diseases/diagnosis , Cattle/blood , Pregnancy Proteins/blood , Pregnancy Tests/veterinary , Animals , Cattle Diseases/blood , Estrus Synchronization , Female , Insemination, Artificial/methods , Insemination, Artificial/veterinary , Parity , Pregnancy
3.
Arq. bras. med. vet. zootec. (Online) ; 71(4): 1165-1170, jul.-ago. 2019. tab, ilus
Article in English | LILACS, VETINDEX | ID: biblio-1038635

ABSTRACT

Poor saddle-fitting is one of the main causes of back pain in horses. Mangalarga Marchador is a popular breed in Brazil, being used mainly for pleasure riding and sports. This study aimed to thermographically assess saddles used in horses of this breed. Thermographic images were obtained from 18 saddles of animals from different categories during a Mangalarga Marchador National Exposition. The evaluation was based on three parameters: contact area symmetry, dorsal midline interaction and total skin contact area (25%, 50%, 75% or 100%). Contact area asymmetry was observed in 83.3% of saddles. Dorsal midline interaction was observed with the same frequency. Only 22.2% of saddles assessed in the present study had panels with contact areas greater than 50%. Based on the results of this essay it can be concluded that thermography is a useful tool for the evaluation of saddle contact area with the back of horses and that there is a high frequency of fitting unconformities in saddles used in Mangalarga Marchador horses.(AU)


O ajuste inadequado da sela é um dos principais causadores de lombalgias em equinos. A raça Mangalarga Marchador está entre as mais populares do Brasil, sendo muito utilizada para cavalgadas e prática de esportes. O presente estudo teve como objetivo avaliar termograficamente as selas utilizadas em cavalos dessa raça. Para tal, foram realizadas imagens termográficas de 18 selas de animais de diversas categorias durante uma Exposição Nacional do Cavalo Mangalarga Marchador. A avaliação foi realizada baseando-se em três parâmetros: simetria da área de contato, interação com a linha média dorsal e área total de contato com a pele (25%, 50%, 75% ou 100%). Em 83,3% das selas avaliadas foi observada assimetria da área de contato. A interação com a linha média dorsal foi observada com a mesma frequência. Apenas 22,2% das selas avaliadas no presente estudo tinham suadouros com área de contato maior que 50%. Com base nos resultados obtidos neste trabalho, conclui-se que a termografia é uma ferramenta útil na avaliação do contato das selas com o dorso dos cavalos e que existe alta frequência de inconformidades no ajuste de selas utilizadas na raça Mangalarga Marchador.(AU)


Subject(s)
Animals , Thermography/veterinary , Low Back Pain/veterinary , Horses , Equipment and Supplies/veterinary , Gait
4.
J Anim Sci ; 94(9): 3703-3710, 2016 Sep.
Article in English | MEDLINE | ID: mdl-27898921

ABSTRACT

A multilocation study examined pregnancy risk (PR) after delaying AI in suckled beef cows from 60 to 75 h when estrus had not been detected by 60 h in response to a 7-d CO-Synch + progesterone insert (CIDR) timed AI (TAI) program (d -7: CIDR insert concurrent with an injection of GnRH; d 0: PGF injection and removal of CIDR insert; and GnRH injection at TAI [60 or 75 h after CIDR removal]). A total of 1,611 suckled beef cows at 15 locations in 9 states (CO, IL, KS, MN, MS, MT, ND, SD, and VA) were enrolled. Before applying the fixed-time AI program, BCS was assessed, and blood samples were collected. Estrus was defined to have occurred when an estrus detection patch was >50% colored (activated). Pregnancy was determined 35 d after AI via transrectal ultrasound. Cows ( = 746) detected in estrus by 60 h (46.3%) after CIDR removal were inseminated and treated with GnRH at AI (Control). Remaining nonestrous cows were allocated within location to 3 treatments on the basis of parity and days postpartum: 1) GnRH injection and AI at 60 h (early-early = EE; = 292), 2) GnRH injection at 60 h and AI at 75 h (early-delayed = ED; = 282), or 3) GnRH injection and AI at 75 h (delayed-delayed = DD; = 291). Control cows had a greater ( < 0.01) PR (64.2%) than other treatments (EE = 41.7%, ED = 52.8%, DD = 50.0%). Use of estrus detection patches to delay AI in cows not in estrus by 60 h after CIDR insert removal (ED and DD treatments) increased ( < 0.05) PR to TAI when compared with cows in the EE treatment. More ( < 0.001) cows that showed estrus by 60 h conceived to AI at 60 h than those not showing estrus (64.2% vs. 48.1%). Approximately half (49.2%) of the cows not in estrus by 60 h had activated patches by 75 h, resulting in a greater ( < 0.05) PR than their nonestrous herd mates in the EE (46.1% vs. 34.5%), ED (64.2% vs. 39.2%), and DD (64.8% vs. 31.5%) treatments, respectively. Overall, cows showing estrus by 75 h (72.7%) had greater ( < 0.001) PR to AI (61.3% vs. 37.9%) than cows not showing estrus. Use of estrus detection patches to allow for a delayed AI in cows not in estrus by 60 h after removal of the CIDR insert improved PR to TAI by optimizing the timing of the AI in those cows.


Subject(s)
Cattle/physiology , Estrus Detection/instrumentation , Estrus/physiology , Insemination, Artificial/veterinary , Animals , Dinoprost/administration & dosage , Estrus Synchronization/methods , Female , Gonadotropin-Releasing Hormone/administration & dosage , Lactation , Pregnancy , Pregnancy Rate , Progesterone/blood , United States
5.
J Comp Pathol ; 150(2-3): 245-52, 2014.
Article in English | MEDLINE | ID: mdl-24447571

ABSTRACT

This paper reports a newly described form of skeletal dysplasia affecting Brazilian hair sheep of the Cabugi breed. This breed is characterized by having a short head and in some cases the animals are smaller and more compact than sheep of similar breeds. Lambs born with craniofacial abnormalities and dwarfism that die at 2-6 months of age are frequent in this breed. In a flock of 68 ewes and three rams of the Cabugi breed, 134 lambs were born over a 4-year period. Of these, 14 (10.4%) had marked cranial abnormalities and dwarfism and died or were humanely destroyed, 43 (32%) had a normal face and 77 (57.5%) had the short face characteristic of the breed. Dwarf lambs were much smaller than normal, with short legs, a domed head with retruded muzzle and protruded mandible, sternal deformities and exophthalmic eyes situated more laterally in the face than normal. Microscopical examination of long bones of the limbs, bones of the base of the skull and vertebrae showed no lesions. Bones from four affected lambs and one control lamb were macerated for morphometric examination. Although the length of the spinal cord was similar, there was disproportionate shortening of the appendicular bones, particularly the distal segments. Thus the disease was defined as a skeletal dysplasia characterized by craniofacial deformity and disproportionate dwarfism. It is suggested that the disease is inherited as an incomplete dominant trait. The shortened face, which is a feature of the Cabugi breed, may represent the heterozygous state and the more severe, often lethal, dwarfism may occur in homozygotes.


Subject(s)
Bone Diseases, Developmental/veterinary , Craniofacial Abnormalities/veterinary , Dwarfism/veterinary , Sheep Diseases/pathology , Animals , Bone Diseases, Developmental/genetics , Bone Diseases, Developmental/pathology , Brazil , Craniofacial Abnormalities/genetics , Craniofacial Abnormalities/pathology , Dwarfism/genetics , Dwarfism/pathology , Female , Male , Phenotype , Sheep , Sheep Diseases/genetics
6.
Article in Portuguese | LILACS | ID: lil-593804

ABSTRACT

O objetivo deste estudo foi caracterizar e verificar a influência de microfissuras na manutenção da esterilidade e do desempenho mecânico de frascos de vidro tipo I, de 4 mL e 13 mL (terminação 13 mm) para produtos esterilizáveis e de 7 mL (terminação 20 mm) para produtos liofilizados, após acondicionamento em linha e simulação de transporte. Microfissuras superficiais em frascos de vidro tipo I podem ser formadas devido ao contato entre o vidro e o ferramental, associado a variações na intensidade da chama, durante o processo produtivo da embalagem. Verificou-se que a tensão residual da embalagem não é alterada pela presença das microfissuras e que os sistemas de fechamento apresentam adequada integridade e propriedades de barreira à umidade. Mesmo com microfissuras superficiais, a manutenção da esterilidade do produto simulante, acondicionado nos frascos esterilizados (4 mL e 13 mL), não apresentaram alteração após o envase em linha e simulação de transporte. No caso do frasco de 7 mL, as microfissuras podem ter contribuído para a ocorrência de alteração de 1% do total das embalagens após o processo de liofilização. Uma maior incidência de quebra por carga vertical, localizada na região do ombro/terminação, foi observada devido à presença das microfissuras. O desempenho mecânico e térmico dos frascos estudados, contudo, não foi alterado pela presença das microfissuras.


The objective of this study was to ascertain the influence of microcracks on the maintenance of sterility and echanical performance of type 1 (i.e. borosilicate) glass vials, of 4 mL and 13 mL (neck 13 mm) for sterile pharmaceutical products and 7 mL (neck 20 mm) for freeze-dried products, after in-line filling and transport simulation. Microcracks in type I glass vials can be formed by contact between the glass and metal tools, when variations in the flame temperature occur during manufacturing. It was found that the residual stress in the glass vials is not altered by the presence of microcracks and that the closure systems are secure and have adequate moisture barrier properties. Even with surface microcracking, the sterility of the simulated product in the vials (4 mL and 13 mL) was maintained after the in-line filling and transport simulation; for the 7 mL glass vial, microcracks may have contributed to the loss of sterility of 1% of the products after freeze-drying. A higher incidence of breakage in the region of the shoulder and neck of the glass vials under vertical load was observed in the presence of microcracks. The mechanical and thermal performance of the glass vials, however, was not impaired by the presence of microcracks.


Subject(s)
Drug Industry , Drug Packaging , Products Technology
7.
Acta Biol Hung ; 59(3): 315-25, 2008 Sep.
Article in English | MEDLINE | ID: mdl-18839698

ABSTRACT

The aim of this work was to evaluate, by comet assay, the possible inducing of DNA lesions in peripheral blood mononuclear cells of rats subjected to acute or chronic food deprivation. Wistar male rats were subjected to 72 h of partial (50%), or total acute food deprivation, and then allowed to recover for different time periods (24, 48 and 72 h). In other experiments, comet scores were determined in peripheral blood mononuclear cells of rats subjected to chronic food deprivation (25% and 50%) for 50 days. Blood aliquots were obtained before, during and after food deprivation. Comet assay was carried out, the comet units photographed and scored (class 0 up to 3). Acute and chronic food-deprived rats presented peripheral blood mononuclear cells with DNA lesions (comet classes 1, 2 and 3) and a significant increase (p<0.05) in the number of comet units compared with its basal level. The increase was proportional to acute food deprivation time, but after being taken off, it progressively returned to basal level after 48 h (partial group) or 72 h (total group). Chronic food-deprived rats presented a progressive increase of comet score up to 5 days, and a decrease thereafter to reach a basal level. Possible mechanisms of DNA lesions are discussed.


Subject(s)
DNA Damage/genetics , Food Deprivation/physiology , Animals , Comet Assay , Leukocytes/metabolism , Male , Rats , Rats, Wistar
8.
Toxicon ; 51(2): 316-9, 2008 Feb.
Article in English | MEDLINE | ID: mdl-18078971

ABSTRACT

Bone and other malformations caused by the ingestion of Mimosa tenuiflora are common in ruminants in the Brazilian semiarid. The aim of this research was to study the teratogenic effects of M. tenuiflora in Wistar rats (Rattus novergicus). The experimental group had 15 females and was fed, from the 6th to the 21st day of pregnancy, with a ration containing 10% of M. tenuiflora seeds. The control group, with 10 females, was fed with the same ration without seeds. There were no differences in weight gains, and food and water consumption between treated and control rats. Ninety bone malformations were observed in 40 of the 101 fetuses born in the experimental group, and four malformations were observed in three of the 58 fetuses born in the control group (p<0.05). The weight and number of ossification centers of the fetuses from the experimental group were higher than those from the control group (p<0.05). It is concluded that the seeds of M. tenuiflora are teratogenic to rat fetuses.


Subject(s)
Mimosa/toxicity , Teratogens/toxicity , Animals , Congenital Abnormalities/etiology , Congenital Abnormalities/pathology , Disease Models, Animal , Female , Pregnancy , Rats , Rats, Wistar , Seeds
9.
In. Sala, Arnaldo; Seixas, Paulo Henrique D'Ângelo. I Mostra SES/SP 2007: experiências inovadoras na gestão da saúde no Estado de São Paulo. São Paulo, SES/SP, 2008. p.121-128, tab, graf.
Monography in Portuguese | LILACS, Sec. Est. Saúde SP, SESSP-CTDPROD, Sec. Est. Saúde SP | ID: lil-503599

ABSTRACT

Segundo a Política Nacional de Saúde do Idoso, um cuidador é "A pessoa, membro ou não da família, que, com ou sem remuneração, cuida do idoso doente ou dependente no exercício de suas atividades diárias, tais como alimentação, higiene pessoal, medicação de rotina, acompanhamento ao serviço de saúde e demais serviços requeridos no cotidiano - como a ida a bancos ou farmácias-, excluídas as técnicas ou procedimentos identificados com profissões legalmetne estabelecidas, particularmente na área de enfermagem". A família costuma ser a principal origem do cuidador e as mulheres adultas e idosas preponderam nestes cuidados. O adoecimento gera crises e momentos de desestruturação para o paciente e seus familiares. Muitas mudanças ocorrem na vida do doente, levando-o a se deparar com limitações, frustações e perdas. Essas mudanças serão definidas pelo tipo de doença, maneira que a doença se manifesta e como segue os seu curso, além do significado que o paciente e família abribuem ao evento. A família necessita se reorganizar e também se adaptar, pois o paciente pode precisar de cuidados. Os papéis e funções devem ser repensados e distribuídos de forma que auxilie o paciente na elaboração de sentimentos confusos e dolorosos ocasionados pelo processo de adoecer. Field e McGaughey apontam alguns problemas dos cuidadores tais como: pobre comunicação médica, tempo de consulta médica imprevisível, cuidado de enfermagem insuficiente e falta de conhecimento do cuidador sobre os cuidados do...


Subject(s)
Aged , Caregivers , Family Health
10.
Homeopathy ; 96(1): 4-16, 2007 Jan.
Article in English | MEDLINE | ID: mdl-17227742

ABSTRACT

BACKGROUND: The quality of information gathered from homeopathic pathogenetic trials (HPTs), also known as 'provings', is fundamental to homeopathy. We systematically reviewed HPTs published in six languages (English, German, Spanish, French, Portuguese and Dutch) from 1945 to 1995, to assess their quality in terms of the validity of the information they provide. METHODS: The literature was comprehensively searched, only published reports of HPTs were included. Information was extracted by two reviewers per trial using a form with 87 items. Information on: medicines, volunteers, ethical aspects, blinding, randomization, use of placebo, adverse effects, assessments, presentation of data and number of claimed findings were recorded. Methodological quality was assessed by an index including indicators of internal and external validity, personal judgement and comments of reviewers for each study. RESULTS: 156 HPTs on 143 medicines, involving 2815 volunteers, produced 20,538 pathogenetic effects (median 6.5 per volunteer). There was wide variation in methods and results. Sample size (median 15, range 1-103) and trial duration (mean 34 days) were very variable. Most studies had design flaws, particularly absence of proper randomization, blinding, placebo control and criteria for analysis of outcomes. Mean methodological score was 5.6 (range 4-16). More symptoms were reported from HPTs of poor quality than from better ones. In 56% of trials volunteers took placebo. Pathogenetic effects were claimed in 98% of publications. On average about 84% of volunteers receiving active treatment developed symptoms. The quality of reports was in general poor, and much important information was not available. CONCLUSIONS: The HPTs were generally of low methodological quality. There is a high incidence of pathogenetic effects in publications and volunteers but this could be attributable to design flaws. Homeopathic medicines, tested in HPTs, appear safe. The central question of whether homeopathic medicines in high dilutions can provoke effects in healthy volunteers has not yet been definitively answered, because of methodological weaknesses of the reports. Improvement of the method and reporting of results of HPTs are required. REFERENCES: References to all included RCTs are available on-line at.


Subject(s)
Homeopathy/organization & administration , Materia Medica/therapeutic use , Research Design/standards , Technology Assessment, Biomedical , Homeopathy/standards , Humans , Meta-Analysis as Topic , Randomized Controlled Trials as Topic , Reproducibility of Results
11.
Food Chem Toxicol ; 45(4): 662-6, 2007 Apr.
Article in English | MEDLINE | ID: mdl-17187912

ABSTRACT

Stevioside is a natural non-caloric sweetener extracted from Stevia rebaudiana (Bertoni) leaves. It has been widely used in many countries, including Japan, Korea, China, Brazil and Paraguay, either as a substitute for sucrose in beverages and foods or as a household sweetener. The aim of this work was to study its genotoxic potentiality in eukaryotic cells. Wistar rats were treated with stevioside solution (4mg/mL) through oral administration (ad libitum) and the DNA-induced damage was evaluated using the single cell gel electrophoresis (comet assay). The results showed that treatment with stevioside generates lesions in peripheral blood, liver, brain and spleen cells in different levels, the largest effect being in liver. Therefore, these undesired effects must be better understood, once the data present here point to possible stevioside mutagenic properties.


Subject(s)
Comet Assay/methods , Diterpenes, Kaurane/toxicity , Glucosides/toxicity , Sweetening Agents/toxicity , Animals , DNA Damage , Rats , Rats, Wistar
12.
Mol Cell Biochem ; 293(1-2): 187-92, 2006 Dec.
Article in English | MEDLINE | ID: mdl-16804638

ABSTRACT

Stevioside is widely used daily in many countries as a non-caloric sugar substitute. Its sweetening power is higher than that of sucrose by approximately 250-300 times, being extensively employed as a household sweetener, or added to beverages and food products. The purpose of this study was to ascertain stevioside genotoxic and cytotoxic potentiality in different biological systems, as its use continues to increase. Agarose gel electrophoresis and bacterial transformation were employed to observe the occurrence of DNA lesions. In addition to these assays, Escherichia coli strains were incubated with stevioside so that their survival fractions could be obtained. Results show absence of genotoxic activity through electrophoresis and bacterial transformation assays and drop of survival fraction of E. coli strains deficient in rec A and nth genes, suggesting that stevioside (i) is cytotoxic; (ii) could need metabolization to present deleterious effects on cells; (iii) is capable of generating lesions in DNA and pathways as base excision repair, recombination and SOS system would be important to recover these lesions.


Subject(s)
Diterpenes, Kaurane/toxicity , Glucosides/toxicity , Mutagens/toxicity , Sweetening Agents/toxicity , DNA, Bacterial/drug effects , Electrophoresis, Agar Gel , Escherichia coli/drug effects , Escherichia coli/growth & development , Escherichia coli/metabolism , Plasmids/drug effects , Plasmids/metabolism , Transformation, Bacterial
14.
Toxicol Lett ; 151(3): 481-7, 2004 Aug 01.
Article in English | MEDLINE | ID: mdl-15261992

ABSTRACT

Plants have been related to our lives, being used as medicine, regardless of scientific evidence of side effects. This work analyses the toxicological effects of Chrysobalanus icaco L. aqueous extract, used in different pathologies. It was studied through: (i) alteration of plasmid pUC 9.1 topology; (ii) survival of bacterial strains submitted, or not, to previous treatment with SnCl2; (iii) transformation efficiency of E. coli strain by the treatment with the plasmid pUC 9.1. In (i), the treatment of the plasmid resulted in DNA single-strand breaks (SSB). A decrease of the lethal effect induced by SnCl2 in presence of the extract was found, while no C. icaco bacterial survival reduction was observed. The transformation efficiency of the plasmid was also reduced. Results suggest that the extract could present a potential genotoxic effect, as demonstrated either by the induction of SSB in plasmid or in transformation efficiency experiments. Finally, it presents an antioxidant action.


Subject(s)
Chrysobalanaceae , Plant Extracts/toxicity , Antioxidants/pharmacology , DNA Damage , Escherichia coli/drug effects , Plant Extracts/pharmacology , Plant Leaves , Plasmids/drug effects , Transformation, Bacterial/drug effects
15.
Biochem Mol Biol Educ ; 32(4): 254-7, 2004 Jul.
Article in English | MEDLINE | ID: mdl-21706734

ABSTRACT

Good quality scientific teaching depends on the ability of researchers to translate laboratory experiments into high school and undergraduate classes, bridging the advanced and basic science with common knowledge. A fast-growing field in biomedical sciences is oxidative stress, which has been associated to several diseases, including cancer and neurodegenerative disorders. We suggest herein a simple methodology for exploring DNA damage as an introductory pathway to these themes. The potential of natural or artificial products to induce DNA strand breaks can be easily tested in supercoiled plasmids incubated with selected products followed by agarose gel electrophoresis. This is designed to detect single and double strand breaks caused by reactive oxygen species generated by the products being tested. The altered topology of the damaged plasmid migrates slowly in the gel, creating a new band. We further introduce the quantitation of supercoiled DNA forms using densitometry of the gel with a digital camera; the values can then be used to estimate the number of breaks per genome using Poisson distribution. The system is inexpensive, rapid, and does not need high-cost equipment and supplies and can be performed in high schools and undergraduate classes with a minimal structure.

16.
17.
Brain Res Bull ; 59(3): 213-6, 2002 Nov 30.
Article in English | MEDLINE | ID: mdl-12431751

ABSTRACT

It was demonstrated that tin, as stannous chloride (SnCl(2)), can facilitate the neuromuscular transmission by accelerating the transmitter release from the nerve terminals in the mouse. When this salt is injected into laboratory animals, it can produce stimulation or depression of the central nervous system. Because calcium (Ca(2+)) influx into the cytoplasm is indispensable to release the transmitter, it would be possible that SnCl(2) increases the Ca(2+) influx at the nerve terminals but not by blocking the K(+) channels. SnCl(2) is known to inhibit the immune response in rodents and to induce tumor generation in thyroid gland. There is no general agreement regarding its genotoxicity and it was discussed that the effects of this salt might depend on the physicochemical conditions and the route of its administration. SnCl(2) has been used in many sectors of human interest, such as food industry and nuclear medicine. This salt is directly administered to human beings endovenously, when it is used as a reducing agent to prepare 99mTc-radiopharmaceuticals which are also used for cerebral studies. SnCl(2) is capable to promote the generation of reactive oxygen species (ROS) that are responsible for the oxidative stress. Oxidative stress has been related with aging and other neurological diseases. So, it is relevant to evaluate other biological effects of SnCl(2). We decided to study these effects using Escherichia coli mutant strains, deficient in DNA repair genes, and supercoiled plasmid DNA. We evaluated the influence of medicinal plants, metal chelating agents, and ROS scavengers against the SnCl(2) deleterious effects. Our results show that SnCl(2) produced lesions in vitro as well as in vivo. This inactivation may be due to the production of ROS. We observed that the genotoxic effect of SnCl(2) was partly inhibited or disappeared, when the treatments were done in the presence of medicinal plants, metal chelating agents, and ROS scavengers. In conclusion, these findings suggest that the SnCl(2) biological effects may be associated with the generation of ROS. Moreover, we can speculate that ROS could be associated with the detrimental effects in the brain due to exogenous or endogenous metals.


Subject(s)
DNA, Bacterial/drug effects , Escherichia coli/drug effects , Tin Compounds/toxicity , Animals , Central Nervous System Depressants/toxicity , Central Nervous System Stimulants/toxicity , Chelating Agents/pharmacology , DNA Damage , DNA Repair/genetics , DNA, Bacterial/analysis , Escherichia coli/genetics , Mutation , Plant Extracts/pharmacology , Plasmids/analysis , Plasmids/drug effects , Plasmids/genetics , Reactive Oxygen Species/antagonists & inhibitors , Species Specificity
18.
Food Chem Toxicol ; 40(10): 1493-8, 2002 Oct.
Article in English | MEDLINE | ID: mdl-12387314

ABSTRACT

The toxic effects of SnCl2 in K562 cells were analyzed in this study. This cell line is resistant to reactive oxygen species (ROS) making it suitable to evaluate the impact of SnCl2 in culture either through ROS or by direct toxicity using Trypan blue dye exclusion, comet and flow cytometry assays. An important loss of viability induced by SnCl2 in a dose-response manner was observed in cells treated in Tris-buffered saline (TBS). This necrotic cell death was further confirmed by flow cytometry. On the other hand, there was no loss of viability when cells were treated in rich medium (RPMI). DNA damage was visualized in SnCl2-treated K562 cells in both tested conditions. The data indicate that SnCl2 induces DNA damage and reduces K562 viability. Both actions seem to be correlated with ROS formation and direct linkage to DNA.


Subject(s)
Mutagens/toxicity , Tin Compounds/toxicity , Cell Survival/drug effects , Coloring Agents , DNA Damage/drug effects , Dose-Response Relationship, Drug , Flow Cytometry , Humans , K562 Cells , Leukemia, Myelogenous, Chronic, BCR-ABL Positive , Reactive Oxygen Species/pharmacology , Trypan Blue
19.
Biochimie ; 84(4): 291-4, 2002 Apr.
Article in English | MEDLINE | ID: mdl-12106906

ABSTRACT

The stannous ion, mainly the stannous chloride (SnCl(2)) salt form, is widely used as a reducing agent to label radiotracers with technetium-99m ((99m)Tc). These radiotracers can be employed as radiopharmaceuticals in nuclear medicine procedures. In this case, there is no doubt about absorption of this complex, because it is intravenously administered in humans, although biological effects of these agents have not been fully understood. In this work we used a bacterial system to study the cytotoxic potential of stannous chloride. It is known that SnCl(2) induces lesions that could be mediated by reactive oxygen species (ROS). We, thus, investigated the existence of cross-adaptive response between hydrogen peroxide (H(2)O(2)) and SnCl(2) and the role of the OxyR system known to promote cellular protection against oxidative damages. Here we describe the results obtained with prior treatment of different Escherichia coli strains with sub-lethal doses of H(2)O(2), followed by incubation with SnCl(2). Our data show that H(2)O(2) is capable of inducing cross-adaptive response against the lethality promoted by SnCl(2), suggesting the OxyR system participation through catalase, alkyl hydroperoxide reductase and superoxide dismutase enzymes


Subject(s)
Adaptation, Biological/physiology , DNA-Binding Proteins , Escherichia coli/drug effects , Hydrogen Peroxide/pharmacology , Repressor Proteins/metabolism , Tin Compounds/toxicity , Transcription Factors/metabolism , Cell Count , DNA Damage , Escherichia coli/physiology , Escherichia coli Proteins , Genotype , Oxidation-Reduction , Oxidoreductases/metabolism , Reactive Oxygen Species/metabolism , Time Factors
20.
Cell Mol Biol (Noisy-le-grand) ; 48(7): 789-91, 2002 Nov.
Article in English | MEDLINE | ID: mdl-12619977

ABSTRACT

Stannous chloride (SnCl2) is employed as a reducing agent to obtain Technetium-99m-labelled radiophamaceuticals in nuclear medicine kits, being injected endovenously in humans. Toxic effects of these kits were not studied, thus making it important to evaluate their impact in humans. In this study, the toxic effects were evaluated from peripheral blood nuclear cells (PBNC) from patients who received radiopharmaceuticals obtained using such kits. The analyses included results performed by comet assay. DNA damage was visualized in PBNC samples collected within a time up to 2 hr, and 24 hr after radiopharmaceutical injection in the patients. Initially we observed an increase of comet signals, which subsequently were reduced to zero after 24 hr. The diminishing of comet amounts probably is associated with DNA repair of damaged cells or with the elimination by apoptosis of cells whose DNA are not repaired.


Subject(s)
DNA Damage , Leukocytes/radiation effects , Radiopharmaceuticals/adverse effects , Apoptosis/radiation effects , Comet Assay , DNA Repair , Humans , Leukocytes/metabolism , Leukocytes/pathology , Technetium/adverse effects , Tin Compounds/adverse effects
SELECTION OF CITATIONS
SEARCH DETAIL
...