In vitro evaluation of surface roughness of titanium abutments after air polishing with different abrasive powders.

OBJECTIVES: The purpose of this study was to evaluate the effects of air polishing with sodium bicarbonate and erythritol powders on surface roughness and morphological changes in titanium abutments. METHODS: A total of 45 grade V titanium discs were divided in three groups: Group A (Control) air polished with air/water; Group B, air polished with sodium bicarbonate powder; and Group C, air polished with erythritol powder. After air polishing, the samples' roughness (Sa) in micrometres were analysed with an optical profilometer. The samples' surface morphology study was conducted via scanning electronic microscope (SEM). Data were described using mean and standard deviation of roughness values (Sa). Inferential analysis was performed using the ANOVA multiple comparison test followed by Tukey's post hoc test. Both tests used a 5% level of significance. RESULTS: After air polishing, average roughness of group A, B and C were 0.036, 0.046 and 0.037 µm, respectively, with statistically significant differences between groups A and B (p < 0.05). No statistically significant differences were found between group A and group C, as well as between group B and C (p > 0.05). As for the morphology analysis, damages to the titanium surface were only observed in group B. CONCLUSIONS: The study indicates that air polishing with erythritol powder maintains titanium abutment integrity better than sodium bicarbonate, which increased surface roughness and caused damage. Erythritol is preferable for minimizing surface alterations and maintaining morphological stability.

Habitat selection in transformed landscapes and the role of forest remnants and shade coffee in the conservation of resident birds.

Biodiversity conservation in transformed landscapes is becoming increasingly important. However, most assessments of the value of modified habitats rely heavily on species presence and/or abundance, masking ecological processes such as habitat selection and phenomena like ecological traps, which may render species persistence uncertain. High species richness has been documented in tropical agroforestry systems, but comparisons with native habitat remnants generally lack detailed information on species demography and habitat use. We generated a multi-species, multi-measure framework to evaluate the role of habitat selection in the adaptation of species to transformed landscapes, and demonstrate that its use could affect how we value the contribution different land uses make to biodiversity conservation. We analysed 7 years of capture-mark-recapture and observation data for twelve species of resident birds present in native forest remnants and shade coffee plantations in a mega-diverse region. We assessed whether species behaved adaptively by evaluating the correlation between measures of habitat preference (occurrence, abundance, fidelity, inter-seasonal variance and age) and performance (body condition, muscle, primary moult, breeding and juveniles) in forest and coffee, and generated hypotheses about their role in species persistence. We documented adaptive habitat selection for seven species, non-ideal selection for four and maladaptive selection for one. While many species showed equal preference and/or equal performance in many traits, in general we found more evidence for birds preferring and/or performing better in forest than coffee, although relationships between our indicators and population adaptation need to be studied further before our proposed framework can be applied to more species and landscapes. While shade coffee can act as a biodiversity-friendly matrix providing complementary or supplementary habitat to a wide range of resident bird species, protecting remnants of native vegetation is still of paramount importance for biodiversity conservation in agricultural landscapes.

La conservación de biodiversidad en paisajes transformados es cada vez más importante. Sin embargo, la mayoría de evaluaciones sobre el valor de los hábitats modificados dependen de la presencia y/o abundancia de especies, ocultando procesos ecológicos como la selección de hábitat y fenómenos como las trampas ecológicas, que hacen incierta la persistencia de las especies. Se han documentado altas riquezas en los sistemas agroforestales tropicales pero las comparaciones con remanentes de hábitats nativos generalmente no proveen información detallada sobre demografía y uso de hábitat. Generamos un marco metodológico multi-especies y multi-medidas para evaluar el papel de la selección de hábitat en la adaptación de las especies a los paisajes transformados, y demostramos que su aplicación podría afectar la forma cómo valoramos la contribución que diferentes usos del paisaje hacen a la conservación de la biodiversidad. Analizamos siete años de datos de captura-marca-recaptura y observaciones para doce especies de aves residentes presentes en remanentes de bosque nativo y plantaciones de café con sombra en una región megadiversa. Valoramos si las especies se comportaban de forma adaptativa evaluando la correlación entre medidas de preferencia (ocurrencia, abundancia, fidelidad, varianza inter-estacional y edad) y desempeño (condición corporal, músculo, muda primaria, reproducción y juveniles) en bosques y cafetales, y generamos hipótesis acerca de su papel en la persistencia de especies. Documentamos selección de hábitat adaptativa para siete especies, no-ideal para cuatro y maladaptativa para una. Aunque muchas especies mostraron preferencias y/o desempeño iguales en muchos rasgos, en general encontramos más evidencia de aves prefiriendo y/o desempeñándose mejor en bosques que en cafetales, aunque las relaciones entre nuestros indicadores y la adaptación poblacional deben ser más estudiadas antes de aplicar el marco que proponemos a más especies y paisajes. Aunque los cafetales con sombra pueden actuar como una matriz amigable con la biodiversidad, proveyendo hábitat complementario o suplementario a una gran variedad de aves residentes, para asegurar la conservación de biodiversidad en los paisajes agrícolas es supremamente importante proteger los remanentes de vegetación nativa.

GDME-based methodology for the determination of free formaldehyde in cosmetics and hygiene products containing formaldehyde releasers.

Formaldehyde is often applied in the industrial production of different products, such as textiles, insulation materials, or cosmetics, due to its preservative and disinfectant properties. However, formaldehyde is classified by the International Agency for Research on Cancer as carcinogenic, and there are numerous studies about the pernicious health effects that frequent exposure to formaldehyde can pose to human health. In the cosmetic industry, compounds called formaldehyde releasers are added during production, with the intent of releasing small amounts of formaldehyde over time. Although there are many methods available for the determination of formaldehyde, they are usually not suitable for the determination of free formaldehyde in cosmetics with formaldehyde releasers in their composition, as they can promote the accelerated release of formaldehyde. In this work, the gas-diffusion microextraction (GDME) technique was used for the extraction of formaldehyde from cosmetic and personal hygiene products. Acetylacetone was used as the derivatization reagent which was later used for the spectrophotometric determination of formaldehyde. The developed methodology exhibits limits of detection (1.98 mg kg-1) and quantification (6.60 mg kg-1) perfectly adequate for the determination of formaldehyde in these samples. Formaldehyde values between 6.9 ± 0.3 and 365 ± 15 mg kg-1 were found in samples containing the formaldehyde releasers DMDM hydantoin, Diazolidinyl urea, and Bronopol. Furthermore, mass spectrometry studies were performed in order to unbiasedly ensure the presence of formaldehyde in every extract. GDME proved to be an economical, simple, and robust alternative for the extraction of free formaldehyde in personal hygiene and cosmetic samples. Graphical abstract ᅟ.

Outcomes after laparoscopic ventral hernia repair: does the number of previous recurrences matter? A prospective study.

BACKGROUND: It is not yet clearly known whether laparoscopic ventral hernia repair (LVHR) is superior to the open approach in recurrent hernias. The aim of this study is to determine the safety and efficacy of laparoscopic technique for ventral hernias and investigate whether these outcomes are affected by the number of previous failed repairs. METHODS: Data from 124 consecutive patients who underwent LVHR using a standardized technique between September 2007 and June 2014 were collected prospectively. In all repairs, a composite prosthesis was tailored to overlap the defect by at least 5 cm and fixed with a double crown of spiral tacks. Clinical follow-up visits were performed at 1 week, 1, 6, and 12 months, and yearly thereafter. Patients were classified in 3 groups (0, 1, and ≥ 2) according to the number of previous hernia repairs for further statistical analysis. RESULTS: Long-term surveillance was available in 116 (93%) patients. Of these, 96 (82.8%) were recurrent hernias. There were 2 (1.7%) conversions, both in recurrent cases, and in 3 (2.6%) patients a hybrid access was used. Mean operating time was 55 min. There was an overall postoperative complication rate of 16%, with no mortality. During a mean follow-up of 30 (range 20-90) months, 3 (2.6%) recurrences were diagnosed 6, 8, and 9 months after surgery, respectively. A univariate analysis related to demographic, clinical, and perioperative variables did not find any significant relationship between the number of previous recurrences and operating time, conversion rate, hospital length of stay, overall morbidity, or recurrence. CONCLUSIONS: This study suggests that laparoscopic approach in recurrent incisional hernias is a safe and feasible alternative to open techniques. Furthermore, our experience supports the idea that LVHR may be the best option for recurrent cases in properly selected patients, independently of the number of previous recurrences.

Hierarchical axion inflation.

We propose a new field theory mechanism for generating an effective trans-Planckian decay constant from sub-Planckian ones. Using the minimal two axions and a hierarchy between two axion decay constants is sufficient for realizing inflation through nonperturbative effects only and with minimal tuning. The inflationary motion is kept entirely within a sub-Planckian domain. We outline possible strategies of embedding the model in a string theory setup.

Colorectal anastomosis facilitated by the use of the LigaSure(®) sealing device: comparative study in an animal model.

BACKGROUND: Recently, there has been speculation about the possibility of fusing intestinal tissue using bipolar sealing devices. In this study we compare in a porcine model the anastomoses created using the LigaSure(®) device with those created with a stapler after section and closure of a rectal stump. METHODS: Thirty pigs underwent laparoscopic colorectal anastomosis. In group A (n = 15), the division of the intestine and distal stump closure were done with a 10-mm LigaSure Atlas(®) device. In group B, these steps were carried out using an endoscopic stapler. Subsequently, the colorectal anastomosis was performed using circular stapling in both groups. The 4-week follow-up included health status, weight gain, blood tests, X-rays, and colonoscopy. Anastomotic tissue was processed to study the mechanical tensile strength and histopathology. RESULTS: There was no difference in the rate of conversion to open surgery or in average operating time between the groups. In the sealing device group, there was a significantly higher rate of failure in rectal stump closure (p = 0.042). There was one death in group B due to anastomotic leak. There was no difference in adhesion formation or stenosis. Mid-section anastomosis area was 89.7 mm(2) in group A compared with 100 mm(2) in group B (p = 0.52). In tensile strength studies, the maximum load resisted by the sample was 13.8 ± 4.9 N (group A) versus 15.7 ± 4.4 N (group B) (p = 0.17). There was no difference between the groups in degree of reepithelialization, number of inflammatory cells, or the presence of microabscesses. CONCLUSIONS: Division and sealing of the rectal stump with the LigaSure(®) device is feasible in the proposed experimental model, but it is less reliable than conventional closure with a stapler, since it has a significantly greater failure rate. Therefore, The LigaSure(®) device should not be used for this purpose in the clinical setting as this could lead to serious and dramatic complications.

Updated distribution of Aedes albopictus (Diptera: Culicidae) in Spain: new findings in the mainland Spanish Levante, 2013.

In 2004, Aedes (Stegomyia) albopictus (Skuse, 1894) was observed for the first time in Catalonia, northeastern Spain. A decade later, it has spread throughout the eastern Mediterranean region of the country and the Balearic Islands. Framed within a national surveillance project, we present the results of monitoring in 2013 in the autonomous communities of the mainland Levante. The current study reveals a remarkable increase in the spread of the invasive mosquito in relation to results from 2012; the species was present and well-established in 48 municipalities, most of which were along the Mediterranean coastline from the Valencian Community to the Region of Murcia.

Combined Percutaneous and Endoscopic Ureterolithotripsy of Calcified Double J Stent.

In urological practice, the routine procedure of placing a double J stent aims to facilitate drainage of the upper urinary system. Despite its temporary nature and the necessity for timely removal, approximately 12% of these stents are retained in patients for extended durations due to various reasons. Forgotten ureteral stents can lead to complications that increase the morbidity and mortality of patients. This report discusses a case of the double J stent that became calcified due to prolonged use and needed to be removed in a combined procedure.

Conjunctival keratoacanthoma: a clinical and histopathological case series.

OBJECTIVE: To present a series of conjunctival keratoacanthomas and provide clinical, histopathological, immunohistochemical, and imaging results that characterize this rare entity. METHODS: A retrospective chart review of records from 2005 to 2023 from the Florida Lions Ocular Pathology Laboratory was conducted. Nine patients with histologically proven conjunctival keratoacanthoma were identified. Data extracted includes demographics, clinical history, diagnostic testing, histopathological and immunohistochemical testing, treatment modalities, and recurrences. RESULTS: Patients' mean age was 55.2 ± 21.1 years (range: 22-83). 77.8% (7/9) of patients were male. 55.6% (5/9) were Hispanic. 55.6% of lesions (5/9) were in right eyes. 55.6% of lesions (5/9) were on the temporal, bulbar conjunctiva. The lesions were rapidly growing, with mean onset time of 4.71 ± 3.30 weeks (range: 2-12). High-resolution anterior segment optical coherence tomography of three lesions revealed hyper-reflective, thickened epithelium with abrupt transition between normal and abnormal epithelium. Underlying disorganized subepithelial tissue was noted. However, the overlying abnormal epithelium caused considerable shadowing, which obscured subepithelial structures. Prominent, keratin-filled, cup-shaped lesions with faulty maturational sequencing that extend full thickness, variably pale cytoplasm, and foci of dyskeratosis and hyperkeratosis were present on all lesions' histopathology. All lesions were surgically excised, but two demonstrated partial spontaneous resolution before surgery. Two patients were lost to follow-up; the remaining seven had no signs of recurrence at a of mean of 36.9 ± 45.4 months (range: 3 to 141 months) of follow-up. CONCLUSIONS: Conjunctival keratoacanthomas are rare lesions of the ocular surface with distinct clinical, histopathologic, and diagnostic features.

Quantification of fractal dimension and Shannon's entropy in histological diagnosis of prostate cancer.

BACKGROUND: Prostate cancer is a serious public health problem that affects quality of life and has a significant mortality rate. The aim of the present study was to quantify the fractal dimension and Shannon's entropy in the histological diagnosis of prostate cancer. METHODS: Thirty-four patients with prostate cancer aged 50 to 75 years having been submitted to radical prostatectomy participated in the study. Histological slides of normal (N), hyperplastic (H) and tumor (T) areas of the prostate were digitally photographed with three different magnifications (40x, 100x and 400x) and analyzed. The fractal dimension (FD), Shannon's entropy (SE) and number of cell nuclei (NCN) in these areas were compared. RESULTS: FD analysis demonstrated the following significant differences between groups: T vs. N and H vs. N groups (p < 0.05) at a magnification of 40x; T vs. N (p < 0.01) at 100x and H vs. N (p < 0.01) at 400x. SE analysis revealed the following significant differences groups: T vs. H and T vs. N (p < 0.05) at 100x; and T vs. H and T vs. N (p < 0.001) at 400x. NCN analysis demonstrated the following significant differences between groups: T vs. H and T vs. N (p < 0.05) at 40x; T vs. H and T vs. N (p < 0.0001) at 100x; and T vs. H and T vs. N (p < 0.01) at 400x. CONCLUSIONS: The quantification of the FD and SE, together with the number of cell nuclei, has potential clinical applications in the histological diagnosis of prostate cancer.

Septic Shock After Intravesical Therapy With Bacillus Calmette-Guerin: A Case Report of a Rare Life-Threatening Complication.

Intravesical therapy with Bacillus Calmette-Guerin (BCG) is the mainstay treatment for high-risk non-muscle invasive bladder cancer. The side effects are usually local and mild. Systemic dissemination of BCG is rare, typically develops soon after instillation, and may present as a severe life-threatening condition. We present a case of a 49-year-old man under chronic haemodialysis who developed septic shock after the first BCG maintenance instillation for bladder carcinoma in situ (CIS). Supportive measures and empiric broad-spectrum antibiotic therapy were promptly started after sample collection for cultures. Lastly, the recurrence of fever raised the initial suspicion of BCG dissemination. The diagnosis was confirmed by the identification of the Mycobacterium tuberculosis complex in blood samples collected and anti-tuberculosis therapy was then initiated. We would like to highlight the need for early recognition of a systemic BCG infection and the importance of starting anti-tuberculosis treatment as early as possible.

The Influence of Perceived Security in Childhood on Adult Self-Concept: The Mediating Role of Resilience and Self-Esteem.

Secure attachment, developed through consistent relationships with attachment figures in childhood, is a crucial factor in fostering healthy interpersonal relationships and a positive self-perception. Part of the positive parenting approach and the theory of affect is taken as a basis to assess how perceived security, as an indicator of secure attachment, predicts adult self-concept through the mediating effects of resilience and positive self-esteem. A quantitative, cross-sectional, and nonprobabilistic study was conducted with 383 participants. We unveiled significant positive associations between perceived security, self-concept, resilience, and positive self-esteem. Path analysis demonstrated that resilience and positive self-esteem sequentially mediate the relationship between perceived security during childhood and adult self-concept. Findings suggest that the ability to cope with adversity and personal acceptance underlie the impact of perceived security on self-concept. It is recommended to promote family intervention programs framed within positive parenting that focus on fostering secure attachment given its influence on adult life. It is also deemed essential to incorporate the promotion of resilience and self-esteem into programs aimed at youths, and adult role models can enhance their self-perception and resilience in the face of potential effects stemming from insecure parenting practices.

A Review on Reinforcements and Additives in Starch-Based Composites for Food Packaging.

The research of starch as a matrix material for manufacturing biodegradable films has been gaining popularity in recent years, indicating its potential and possible limitations. To compete with conventional petroleum-based plastics, an enhancement of their low resistance to water and limited mechanical properties is essential. This review aims to discuss the various types of nanofillers and additives that have been used in plasticized starch films including nanoclays (montmorillonite, halloysite, kaolinite, etc.), poly-saccharide nanofillers (cellulose, starch, chitin, and chitosan nanomaterials), metal oxides (titanium dioxide, zinc oxide, zirconium oxide, etc.), and essential oils (carvacrol, eugenol, cinnamic acid). These reinforcements are frequently used to enhance several physical characteristics including mechanical properties, thermal stability, moisture resistance, oxygen barrier capabilities, and biodegradation rate, providing antimicrobial and antioxidant properties. This paper will provide an overview of the development of starch-based nanocomposite films and coatings applied in food packaging systems through the application of reinforcements and additives.

A penile fracture hidden behind a urethral bleeding.

Penile fracture with urethral injury is uncommon. Diagnosis is usually based on clinical history and physical examination. Nonetheless, atypical presentation obliges complementary examinations to be performed. We report a case of a 45-years-old man with urethral bleeding after a blunt penile trauma that was ultimately diagnosed as having a cavernous body laceration on top of an urethral rupture.

Public views on tourist beach environment from multinational countries and ensuing changes during global epidemic.

The continuous endemic of the new SARS-CoV-2 virus brought a halt to the world's activities from February 2020. Our study intends to gauge public perceptions on the consequences of post-pandemic changes on the marine environment, particularly as they are related to tourist beach amenities. Totally, 16 nations' knowledge and views on various environmental viewpoints over the effects of epidemic were gathered through public polls live on social media during social confinement in 2020. The results indicate that around 85% of respondents were most concerned about the alarming sights of widespread plastic trash and the increase of dangerous biomedical wastes through wastewater in the marine ecosystem. The outcomes of this study will undoubtedly aid in the establishment of a management strategy and for future studies on the consequences of any epidemic on the beaches.

Smelling Peppers and Pout Submitted to Convective Drying: Mathematical Modeling, Thermodynamic Properties and Proximal Composition.

Pepper (Capsicum spp.) is among the oldest and most cultivated crops on the planet. Its fruits are widely used as natural condiments in the food industry for their color, flavor, and pungency properties. Peppers have abundant production; on the other hand, their fruits are perishable, deteriorating within a few days after harvesting. Therefore, they need adequate conservation methods to increase their useful life. This study aimed to mathematically model the drying kinetics of smelling peppers (Capsicum chinense) and pout peppers (Capsicum chinense Jacq.) to obtain the thermodynamic properties involved in the process and to determine the influence of drying on the proximal composition of these peppers. Whole peppers, containing the seeds, were dried in an oven with forced air circulation, at temperatures of 50, 60, 70, and 80 °C, with an air speed of 1.0 m/s. Ten models were adjusted to the experimental data, but the Midilli model was the one that provided the best values of coefficient of determination and lowest values of the mean squared deviation and chi-square value in most of the temperatures under study. The effective diffusivities were well represented by an Arrhenius equation, appearing in the order of 10-10 m2·s-1 for both materials under study, since the activation energy of the smelling pepper was 31.01 kJ·mol-1 and was 30.11 kJ·mol-1 in the pout pepper, respectively. Thermodynamic properties in both processes of drying the peppers pointed to a non-spontaneous process, with positive values of enthalpy and Gibbs free energy and negative values of entropy. Regarding the influence of drying on the proximal composition, it was observed that, with the increase in temperature, there was a decrease in the water content and the concentration of macronutrients (lipids, proteins, and carbohydrates), providing an increase in the energy value. The powders obtained in the study were presented as an alternative for the technological and industrial use of peppers, favoring obtaining a new condiment, rich in bioactives, providing the market with a new option of powdered product that can be consumed directly and even adopted by the industry as a raw material in the preparation of mixed seasonings and in the formulation of various food products.

Is Your Kid Actin Out? A Series of Six Patients With Inherited Actin-Related Protein 2/3 Complex Subunit 1B Deficiency and Review of the Literature.

BACKGROUND: Hereditary actin-related protein 2/3 complex subunit 1B deficiency is characterized clinically by ear, skin, and lung infections, bleeding, eczema, food allergy, asthma, skin vasculitis, colitis, arthritis, short stature, and lymphadenopathy. OBJECTIVE: We aimed to describe the clinical, laboratory, and genetic features of six patients from four Mexican families. METHODS: We performed exome sequencing in patients of four families with suspected actinopathy, collected their data from medical records, and reviewed the literature for reports of other patients with actin-related protein 2/3 complex subunit 1B deficiency. RESULTS: Six patients from four families were included. All had recurrent infections, mainly bacterial pneumonia, and cellulitis. A total of 67% had eczema whereas 50% had food allergies, failure to thrive, hepatomegaly, and bleeding. Eosinophilia was found in all; 84% had thrombocytopenia, 67% had abnormal-size platelets and anemia. Serum levels of IgG, IgA, and IgE were highly increased in most; IgM was normal or low. T cells were decreased in 67% of patients, whereas B and NK cells were increased in half of patients. Two of the four probands had compound heterozygous variants. One patient was successfully transplanted. We identified 28 other patients whose most prevalent features were eczema, recurrent infections, failure to thrive, bleeding, diarrhea, allergies, vasculitis, eosinophilia, platelet abnormalities, high IgE/IgA, low T cells, and high B cells. CONCLUSION: Actin-related protein 2/3 complex subunit 1B deficiency has a variable and heterogeneous clinical spectrum, expanded by these cases to include keloid scars and Epstein-Barr virus chronic hepatitis. A novel deletion in exon 8 was shared by three unrelated families and might be the result of a founder effect.

Maternal diet in pregnancy and acute leukemia in infants: a case-control study in Mexico City.

Introduction: Epidemiological studies around the world on acute leukemia (AL) and risk factors in infants are scarce. Infant AL has been proposed to originate in utero, which facilitates its study by establishing a short exposure time in pregnant women to environmental and dietary factors that could contribute to the risk of or protection against leukemia. We hypothesized that maternal diet during pregnancy may be an important factor involved in AL in offspring. Methods: We conducted a hospital-based case-control study from 2010 to 2019 on maternal diet during pregnancy in nine high-specialty public hospitals of different health institutions that diagnose and offer treatment to children with AL in Mexico City. Cases (n=109) were children ≤24 months of age with de novo diagnosis of AL, and controls (n=252) were children obtained in hospitals from second-level medical care matched for age, sex, and health institution. Maternal diet during pregnancy was obtained by a semiquantitative food frequency questionnaire. Unconditional logistic regression models were used to assess the association between food groups and infant AL. Potential confounders were assessed by constructing directed acyclic graphs (DAGs) with Dagitty software in which adjusted options were identified for the construction of unconditional logistic regression models. Results: Cases were slightly predominantly female (52.3%). The years of education of the mother in cases and controls was 0-9 on average, and those who reported smoking cigarettes and consuming alcohol during pregnancy did so at a low frequency. Regarding the mother's diet, the main findings were that the consumption of allium vegetables during pregnancy was inversely associated with AL for medium and high consumption (OR=0.26, 95% CI 0.14-0.46; P-trend< 0.001). In contrast, the high consumption of high-fat dairy products had a positive association with AL (OR=2.37, 95% CI 1.30-4.34; P-trend<0.001). No association was found between consumption of topoisomerase II inhibitor foods during pregnancy and AL. Conclusion: The results suggest that maternal intake during pregnancy of allium vegetables, specifically garlic, is inversely associated with the development of AL in children ≤24 months old. On the other hand, consumption of high-fat dairy products is positively associated with AL in children ≤24 months old.

Tributyltin impairs the reproductive cycle in female rats.

Triorganotins are environmental contaminants, commonly used in antifouling agents for boats, that bioaccumulate and thus are found in mammals and humans due to ingestion of contaminated seafood diets. The importance of triorganotins as environmental endocrine disruptors and consequent reproductive toxicity in different animal models is well known; however, the adverse effects on reproductive cycle are less well understood. The potential reproductive toxicity of tributyltin (TBT) on regular reproductive cycling of female rats was examined. Wistar female rats (12 wk old, weighing approximately 230 g) were divided into two groups: control (vehicle, ethanol 0.4%) and tributyltin (100 ng/kg/d, 7 d/wk, for 16 d by gavage). Tributyltin significantly decreased the cycle regularity (%), duration of the reproductive cycle, the proestrus and diestrus phases, and number of epithelial cell in proestrus phase. TBT also increased the duration of metestrus and the number of cornified cells in this phase. Ovary weight and serum 17ß-estradiol levels decreased markedly, accompanied by a significant increase in progesterone levels. Histological analysis showed apoptotic cells in corpus luteum and granulosa cells layer, with cystic follicles after TBT exposure. Tributyltin also elevated number of atretic follicles and corpoa lutea. The micronucleus (MN) test, using Chinese hamster ovary cells, demonstrated a concentration-dependent mutagenic effect of TBT, and at 2.0 × 10(-2)ng/ml most of the cells were nonviable. The toxic potential of TBT over the reproductive cycle may be attributed to changes found in the ovarian weight, unbalanced levels of sexual female hormones, and number of ovarian follicles and corpora lutea.