DNA oxidative damage in oral cancer: 8-hydroxy-2´-deoxyguanosine immunoexpression assessment.

BACKGROUND: The development and establishment of oral squamous cell carcinoma are confined to carcinogenesis, which involves oxidative stress via oxygen-free radical production as a hydroxyl radical (HO•), considered the most important cause of oxidative damage to basic biomolecules since it targets DNA strands. 8-Hydroxy-2´-deoxyguanosine (8-OHdG) is considered a free radical with a promutagenic capacity due to its ability to pair with adenosine instead of cytosine during replication. MATERIAL AND METHODS: We collected 30 paraffin-embedded tissue samples of OSCC from patients treated between 2013 and 2018. We recorded risk habits, disease stage, disease free survival and death with at least 3 years of follow-up. 8-Hydroxyguanosine was evaluated by immunohistochemistry and subsequently classified as weak-moderate or strong positive expression. Additionally, we noted whether it was expressed in the cytoplasm and/or nucleus. RESULTS: Most of the cases expressed 8-OHdG with a strong intensity (80%). All neoplastic cells were preferentially stained in only the cytoplasm (70.0%), but nuclear positivity was found in 30%, independent of the intensity. Based on the location in the cytoplasm and/or nucleus, tumors >4 cm showed a high frequency (95.5%) of 8-OHdG expression in only the cytoplasm, with a significant difference (p value 0.001). Additionally, overall survival was affected when immunoexpression was present in the cytoplasm and nucleus because all deaths were in this group were statistically significant (p value = 0.001). CONCLUSIONS: All tumors showed DNA oxidative damage, and 8-OHdG was preferentially expressed in the cytoplasm. This finding was associated with tumor size and, when present in the nucleus, might also be related to death.

Purification of phlorotannins from Macrocystis pyrifera using macroporous resins.

Phlorotannins are secondary metabolites produced by brown seaweed, which are known for their nutraceutical and pharmacological properties. The aim of this work was to determine the type of macroporous resin and the conditions of operation that improve the purification of phlorotannins extracted from brown seaweed, Macrocystis pyrifera. For the purification of phlorotannins, six resins (HP-20, SP-850, XAD-7, XAD-16N, XAD-4 and XAD-2) were assessed. The kinetic adsorption allowed determination of an average adsorption time for the resins of 9h. The highest level of purification of phlorotannins was obtained with XAD-16N, 42%, with an adsorption capacity of 183±18mgPGE/g resin, and a desorption ratio of 38.2±7.7%. According to the adsorption isotherm the best temperature of operation was 25°C, and the model that best described the adsorption properties was the Freundlich model. The purification of phlorotannins might expand their use as a bioactive substance in the food, nutraceutical and pharmaceutical industries.

Near-infrared chemical imaging and its correlation with the mechanical properties of chitosan-gelatin edible films.

Plasticizers influence the physical properties of edible films by their interaction with the film-forming polymers. Using near-infrared chemical imaging, it is possible to characterize the interaction between compounds through the analysis of their relative presence throughout the film (abundance) and their variability. These parameters and standard mechanical properties were used to characterize the interaction between gelatin, chitosan and several plasticizers, pure or in binary combinations. Triacetin showed the least interaction with the polymers, while polyethylene glycol 400 and glycerol showed high interaction with them. In addition, we observed that the tensile strength of the film was well correlated with the variability of gelatin and chitosan.

Characterization of pressurized hot water extracts of grape pomace: chemical and biological antioxidant activity.

Pressurized hot water extracts obtained at different temperatures possess different compositions and antioxidant activities and, consequently, different bioactivities. We characterized two pressurized hot water extracts from grape pomace obtained at 100°C (GPE100) and 200°C (GPE200) in terms of antioxidant activity and composition, as well as protective effect on cell growth and mitochondrial membrane potential (Δψm) in a HL-60 cell culture under oxidative conditions. GPE100 extracts were richer in polyphenols and poorer in Maillard reaction products (MRPs) than were GPE200 extracts. Moreover, hydroxymethylfurfural was detected only in GPE200. Both extracts exhibited similar protective effects on cell growth (comparable to the effect of trolox). In addition, GPE100 strongly decreased the Δψm loss, reaching values even lower than those of the control culture. This protective effect may be related to its high polyphenols content. At the highest concentration assessed, both extracts showed strong cytotoxicity, especially GPE200. This cytotoxicity could be related to their MRPs content.

Effects of distillation system and yeast strain on the aroma profile of Albariño (Vitis vinifera L.) grape pomace spirits.

Orujo is a traditional alcoholic beverage produced in Galicia (northwest Spain) from distillation of grape pomace, a byproduct of the winemaking industry. In this study, the effect of the distillation system (copper charentais alembic versus packed column) and the yeast strain (native yeast L1 versus commercial yeast L2) on the chemical and sensory characteristics of orujo obtained from Albariño (Vitis vinifera L.) grape pomace has been analyzed. Principal component analysis, with two components explaining 74% of the variance, is able to clearly differentiate the distillates according to distillation system and yeast strain. Principal component 1, mainly defined by C6-C12 esters, isoamyl octanoate, and methanol, differentiates L1 from L2 distillates. In turn, principal component 2, mainly defined by linear alcohols, linalool, and 1-hexenol, differentiates alembic from packed column distillates. In addition, an aroma descriptive test reveals that the distillate obtained with a packed column from a pomace fermented with L1 presented the highest positive general impression, which is associated with the highest fruity and smallest solvent aroma scores. Moreover, chemical analysis shows that use of a packed column increases average ethanol recovery by 12%, increases the concentration of C6-C12 esters by 25%, and reduces the concentration of higher alcohols by 21%. In turn, L2 yeast obtained lower scores in the alembic distillates aroma profile. In addition, with L1, 9% higher ethanol yields were achieved, and L2 distillates contained 34%-40% more methanol than L1 distillates.

Cholinesterase inhibition and behavioral toxicity of carbofuran on Oreochromis niloticus early life stages.

Nile tilapia Oreochromis niloticus at 9 days post-hatch were exposed in semi-static experiments to the carbamate insecticide carbofuran, which is applied in agricultural systems in Brazil. Although the molecular mechanism of carbofuran toxicity is well known, a detailed understanding of the ecological mechanisms through which carbofuran effects can propagate towards higher levels of biological organization in fish is incomplete. Mortality rates were quantified for larvae exposed for 96 h to 8.3, 40.6, 69.9, 140, 297 and 397 µg/L carbofuran, and the LC(50) 96 h was 214.7 µg/L. In addition, the biochemical biomarker cholinesterase inhibition and behavioral biomarkers related to vision, swimming, prey capture and predator avoidance were quantified in individual larvae, as well as their growth in weight. The behavioral parameters were quantified by analysis of digitally recorded videos of individual larvae within appropriate experimental setups. The activity of the enzyme cholinesterase decreased after exposure to carbofuran with a lowest observed effects concentration (LOEC) of 69.9 µg/L. Visual acuity deficits were detected after carbofuran exposure with a LOEC of 40.6 µg/L. Swimming speed decreased with carbofuran exposure, with a LOEC of 397.6 µg/L. The number of attacks to prey (Daphnia magna nauplii) decreased in larvae exposed to carbofuran, with a LOEC of 397.6 µg/L. Growth in weight was significantly reduced in a dose dependent manner, and all carbofuran groups exhibited a statistically significant decrease in growth when compared to controls (p<0.05). The number of predator attacks necessary to capture larvae decreased after exposure to carbofuran, and the LOEC was 69.9 µg/L. These results show that exposure of sensitive early life stages of tilapia O. niloticus to sublethal concentrations of carbofuran can affect fundamental aspects of fish larval ecology that are relevant to recruitment of fish populations, and that can be better understood by the application of behavioral biomarkers.

Naphthoimidazoles promote different death phenotypes in Trypanosoma cruzi.

SUMMARY: In a screening of 65 derivatives of natural quinones using bloodstream trypomastigotes of Trypanosoma cruzi, the 3 naphthoimidazoles derived from beta-lapachone - N1, N2 and N3--were selected as the most active. Investigation of their mode of action led to the characterization of mitochondrion, reservosomes and DNA as their main targets, and stimulated further studies on death pathways. Ultrastructural analysis revealed both autophagic (autophagosomes) and apoptotic-like (membrane blebbing) phenotypes. Flow cytometry analysis showed, in N2-treated trypomastigotes, a small increase of phosphatidylserine exposure, and a large increase in the percentage of necrosis, caused by N1 or N2. These death phenotypes were not detected in treated epimastigotes. The strong increase in labelling of monodansyl cadaverine, the inhibition of the death process by wortmannin or 3-methyladenine, the overexpression of ATG genes in treated epimastigotes, together with ultrastructural evidence point to autophagy as the predominant phenotype induced by the naphthoimidazoles. However, there are other pathways occurring concomitantly with variable intensities, justifying the need to detail the molecular features involved.

Isolation of cardiac mast cells in experimental Trypanosoma cruzi infection.

Mast cells (MC) secrete diverse pre-stored chemical mediators that are pivotal in inflammatory and fibrotic etiologies, such as Trypanosoma cruzi-induced myocardiopathy. However, due to reduced number of cardiac MC, in situ and in vitro identification, and difficult tissue isolation, these cells are rarely addressed. In this work we optimized the identification of cardiac and peritoneal MC and developed an enzymatic method for MC isolation using control and T. cruzi-infected mice. MC were identified by: toluidine blue (TB); alcian blue (AB)/safranin (S); AB or a mixed solution composed by AB/S/TB. Previous evaluations of cardiac MC in T. cruzi infection were based on TB staining and our results using AB/S/TB solution showed an increase in, at least, five times the detection of MC. This mixed solution may improve the identification of MC populations also from skin, mucosa and tissues that are infected by other pathogens or under the influence of chronic inflammation, leading to more precise results. Furthermore, the appropriate combination of samples (frozen/unfixed/thick slices) and staining protocols can assure the best evaluation of MC. We have also isolated cardiac MC using collagenase and developed a highly efficient 60%/70% Percoll-graded protocol that enriched in, at least, 95% the population of cardiac MC.

Mitochondrial disruption and DNA fragmentation in Trypanosoma cruzi induced by naphthoimidazoles synthesized from beta-lapachone.

Three naphthoimidazoles presenting aromatic groups attached to the imidazole ring were the most active against trypomastigotes of Trypanosoma cruzi between 45 derivatives from beta-lapachone. N1 is active against the three forms of the parasite. In this work, we investigated N2 and N3 and analyzed the effect of the three derivatives on metacyclogenesis, endocytosis, and cell cycle. In epimastigotes, N2 and N3 blocked the cell cycle, inhibited succinate cytochrome c reductase, metacyclogenesis, and induced damage to mitochondrion, Golgi, and reservosomes. In treated trypomastigotes, there were alterations in the mitochondrion, nucleus and kinetoplast, and DNA fragmentation. Preincubation with cysteine protease inhibitors reversed the effect of N1, N2, and N3. Such reversion and ultrastructural alterations suggest the involvement of autophagy in parasite death. Ultrastructural, flow cytometry, and biochemical studies suggest that naphthoimidazoles interferes with the energetic metabolism and induces DNA fragmentation.

Predictive controller evaluation including non-stationary high frequency noise and outliers for batch solid substrate fermentation bioreactors.

Optimum operation and automatic control of large-scale solid substrate fermentation (SSF) bioreactors is difficult. Though advanced control algorithms can handle most challenges encountered properly, for real-time SSF processes such controllers are expensive and time consuming to design and tune. With these considerations, advanced control algorithm tests using realistic simulations appear more appropriate. We used a phenomenological process model of an SSF pilot bioreactor, coupled with a realistic noise model, to test linear model predictive controllers. We focused on the effect noise has on the performance of the control algorithms, and how to enhance performance using a combination of low-pass (Butterworth) and outlier shaving (Hampel) filters. In simulations undertaken directly with the phenomenological model it was relatively straightforward to achieve good control performance. Nevertheless, control degraded sharply when the output of the phenomenological model was contaminated with noise using our realistic noise model, even with proper signal filtering.

Adiabatic formation of quasibound states of antihydrogen.

The classical trajectory of an initially unbound positron within the electric field of an antiproton and a uniform magnetic field is simulated in three dimensions. Several simulations are run incorporating experimental parameters used for antihydrogen production, which has been achieved by two different groups [M. Amoretti, Nature (London) 419, 456 (2002); G. Gabrielse, Phys. Rev. Lett. 89, 213401 (2002)]. The simulations indicate that temporary bound states of antihydrogen can form at positive energies, where the energy of the system is defined to be zero when the positron and antiproton are at rest with infinite separation. Such quasibound states, which form only when the magnetic field is present, are typically smaller than in a dimension perpendicular to the magnetic field. An analytical model is developed for a formation cross section, and it is found that quasibound states may form more frequently than stable Rydberg states.

Assessment of two devices for in vitro preparation of human sperm.

The aim of the study was to assess and compare the efficiency of the ZSC-II versus the Sperm Select techniques in preparing human sperm from normozoospermic patients for use in intrauterine insemination and other assisted reproductive technologies. Twenty-five patients were included in the study. Semen was collected at intercourse and processed via 2 sperm preparation methods. Recovery of motile sperm and other sperm qualitative measurements were evaluated before and after ZSC-II and Sperm Select sperm preparation. Sperm qualitative measurements were not significantly different after the ZSC-II and Sperm Select procedures (p > .05). Differences (p < .05) were noted between the 2 procedures in the number of sperm recovered. A higher survival rate (longevity test, 72 h) was observed after ZSC-II sperm preparation and recovery. The ZSC-II procedure yielded higher total motile sperm than the Sperm Select. The superiority in longevity may suggest possible advantages in obtaining higher fertilization and pregnancy rates.

[Circadian alterations of the cardiovascular system]. / Alteraciones circadianas del sistema cardiovascular.

Circadian variations have been known for a long time for the influence they have on the physiological systems, including the cardiovascular system. The study of the mechanisms with circadian variation that change the function of the cardiovascular system and its diseases has increased greatly in recent years due to its clinical prominence. Through these studies, physiopathology, epidemiology and factors involved in cardiovascular diseases are more understandable. Thus, the incidence of cardiac events has been clearly associated with the morning hours, as well as the possible mechanisms involved in this variation during the daytime hours. The arterial blood pressure, plasma catecholamine levels and cortisol, platelet aggregation, and fibrinolytic system action are the most implicated mechanisms. From this knowledge, it is possible to design new therapeutic strategies that should consider the time of the day of higher risk for the onset of cardiovascular events.

Evaluation of techniques for the cryopreservation of washed spermatozoa: comparisons between Ham's F-10 and TEST-yolk media.

The objective of this study was to develop new techniques for the cryopreservation of washed spermatozoa. Two media (Ham's F-10 and nonthermoprecipitated TEST-yolk buffer [NT-TYB]) containing 7% (v/v) glycerol were compared to semen cryopreservation by adding glycerol directly to the semen. Twenty four men collected a semen specimen each after 4 days of sexual abstinence via the use of a semen collection device at intercourse. Specimens were assessed for volume (ml), count (x 10(6)), percentage and grade of motility, morphology (% normal) and acrosomal status (% intact acrosomes). Each ejaculate was split into 3 aliquots (Aliquots 1 to 3) and processed for freezing. Aliquot 1 was prepared for cryopreservation by adding glycerol (7% [v/v] final concentration) directly via a dropwise mode. Aliquot 2 and 3 were diluted 1:1 (v/v) with Ham's F-10 and NT-TYB, respectively. Aliquots 2 and 3 were then centrifuged (400 x g for 10 minutes) and resuspended into the corresponding media containing 7% (v/v) glycerol to complete the sperm wash procedure. All aliquots were frozen in 0.5 ml french straws. Sperm specimens were frozen in liquid nitrogen (LN2) vapor from +23 degrees C to -68 degrees C at a slow rate (2.3 degrees C/minute), after which the specimens were plunged directly into LN2 and stored for 30 days. The quality of the spermatozoa were monitored throughout each step of the overall procedure by measuring the motility characteristics of the spermatozoa. Straws corresponding to each aliquot were thawed in a water bath at 37 degrees C for 2 minutes, followed by assessment of sperm motility and acrosomal status. The percentage of motility after thawing was 31.6 +/- 5.6%, 32.8 +/- 1.8% and 37.3 +/- 1.9% in Aliquots 1 to 3, respectively. Similarly, the grade of motility was 2.4 +/- 0.2, 2.6 +/- 0.1 and 3.0 +/- 0.1 in Aliquots 1 to 3, respectively. The acrosomal status (% intact acrosomes) in Aliquots 1 to 3 was 41.2 +/- 2.6, 43.1 +/- 3.6 and 51.6 +/- 4.5, respectively. The results suggest that the characteristics of spermatozoa washed and frozen in NT-TYB (Aliquot 3) were improved over those spermatozoa prepared via direct addition of glycerol to the semen (Aliquot 1) or by using Ham's F-10 (Aliquot 2). The most significant reduction noted during freezing was in the loss of acrosomal integrity. The results obtained in this study point out that washed spermatozoa can be cryopreserved with some success and that the recovered spermatozoa could be used for intrauterine insemination in an artificial insemination program using husband's or donor sperm, or for the various assisted reproductive technology procedures. It is the opinion of the authors that the information generated in this study is of importance for those scientists and clinicians involved in the handling and manipulation of cryopreserved spermatozoa.

Fertilization potential and qualitative characteristics of human spermatozoa after short-term cryostorage at 5 degrees C in two different TEST-yolk buffer preparations.

Use of the media TEST-yolk buffer (TYB) in semenology today enables the short-term incubation and cryostorage of spermatozoa and its subsequent use in the various assisted reproductive technologies (ART). Preparation of TYB media involves the addition of egg yolk (20% v/v) to a physiological solution of the zwitterion buffers TES and Tris. The TYB is usually thermoprecipitated to remove the majority of the egg yolk globules and other macromolecules from the medium. However, removal of these egg yolk constituents could possibly eliminate or reduce essential factors that could enhance the sperm viability and fertilization potential after short-term dilution and storage. Improvements in the quality of the TYB could add greater benefits to those techniques employed in the various forms of ART. The objectives of the investigation were 1) to study the sperm qualitative characteristics following short-term cryostorage at 5 degrees C in either thermoprecipitated (T-TYB) or non-thermoprecipitated (NT-TYB), and 2) to compare the fertilizing potential of spermatozoa stored for 24 hours at 5 degrees C in the two TYB preparations. In Experiment 1, semen specimens from 15 patients were collected, assessed and split into two aliquots. Sperm specimens were processed by diluting 1:1 (v/v) with the T-TYB or NT-TYB, followed by centrifugation and reconstitution of the specimen to its initial volume with the corresponding TYB medium. Sperm specimens were cryostored for 1, 2, 24, 48 and 72 hours. Samples were taken at each interval and placed in a 37 degrees C water bath and allowed to warm for 15 minutes after each cryostorage interval. Semen specimens were assessed for percentage and grade of motility. The results of this study indicated that, although the NT-TYB yielded better results than the T-TYB, overall those differences were not statistically significant. In Experiment 2, the fertilization potential of spermatozoa recovered after 24 hours of cryostorage in the two TYB preparations and further prepared via filtration, was assessed by the sperm penetration assay (SPA) using zona-free hamster oocytes. The average penetration rate (PR) and penetration index (PI) were significantly better for the NT-TYB than for the T-TYB. The PR was 54% vs. 25%, and the PI 0.78 and 0.27 for spermatozoa incubated in the NT-TYB vs. T-TYB. The range of penetration was also much lower for the T-TYB (6 to 100%) preparation when compared to the NT-TYB (22 to 100%). The highest penetrator showed 100% for both preparations. However, the lowest penetrator showed 6% for the T-TYB and 22% for the NT-TYB. The data obtained in this study suggest that both TYB preparations can be employed in short-term cryostorage (5 degrees C) of human spermatozoa and can adequately maintain the qualitative characteristics of those spermatozoa. The data also showed that the NT-TYB preparation yielded sperm samples of higher fertilization potential, thus possibly establishing the superior usefulness of the NT-TYB in an ART program.

Assessment of a tablet drug delivery system incorporating nonoxynol-9 coprecipitated with polyvinylpyrrolidone in preventing the onset of pregnancy in rabbits.

OBJECTIVE: To assess the in vivo efficacy of the tablet drug delivery system containing nonoxynol-9 coprecipitated with polyvinylpyrrolidone by delivering the spermicidal agents vaginally and evaluating their ability to prevent the onset of pregnancy in rabbits. DESIGN: Controlled clinical study. SETTING: Division of Laboratory and Animal Resources, College of Pharmacy, University of Kentucky. ANIMAL(S): Forty-two New Zealand White female rabbits. INTERVENTION(S): The rabbits were artificially inseminated at various intervals after vaginal insertion of the tablet drug delivery system containing either polyvinylpyrrolidone only (0 minutes) or nonoxynol-9 coprecipitated with polyvinylpyrrolidone (polyvinylpyrrolidone/nonoxynol-9; 0, 3, 30, 180, and 360 minutes). The rabbits were induced to ovulate 6 hours before insemination by i.m. injection of hCG (200 IU). MAIN OUTCOME MEASURE(S): The onset of pregnancy in the rabbits was evaluated after insertion of the tablet drug delivery system containing polyvinylpyrrolidone only or polyvinylpyrrolidone/nonoxynol-9 at various intervals, followed by artificial insemination. RESULT(S): The onset of pregnancy was not reduced significantly when the tablet drug delivery system containing polyvinylpyrrolidone or polyvinylpyrrolidone/nonoxynol-9 was used and insemination was performed immediately after tablet insertion (time 0). However, pregnancy rates (PRs) were reduced significantly in the rabbits that received the tablet drug delivery system containing polyvinylpyrrolidone/nonoxynol-9 and were inseminated at 3, 30, 180, and 360 minutes after tablet insertion. The highest PR reduction occurred between 30 and 180 minutes after insertion of the tablet drug delivery system containing polyvinylpyrrolidone/nonoxynol-9. CONCLUSION(S): The tablet drug delivery system is an efficient method of delivering the tested spermicidal agents vaginally. The design and dosage used in preparing the tablet drug delivery system provide short- and long-term release of the spermicidal agents, which results in almost immediate and extended enhancement of their contraceptive properties.

Effects of seminal plasma from cigarette smokers on sperm viability and longevity.

OBJECTIVE: To evaluate the effects of cigarette smoking on the ability of seminal plasma (SP) to maintain sperm viability. DESIGN: Clinical randomized study. Spermatozoa from cigarette smoking or nonsmoking subjects were reconstituted in SP from smokers and nonsmokers and in modified Ham's F-10 medium, followed by sperm quality assessment during a 48-hour incubation period. SETTING: Andrology Institute of Lexington, Lexington, Kentucky. PATIENT(S): Twenty men who had been smoking cigarettes for longer than 3 years (30 cigarettes per day or more) and 20 nonsmokers participated in this study. MAIN OUTCOME MEASURE(S): Improvement in sperm viability by removal of SP--and associated detrimental factors present in the SP--from smoker subjects. RESULT(S): The results obtained indicate that the quality of spermatozoa obtained from nonsmokers was superior to that of smokers. The SP from the two patient groups had a definite effect on their respective sperm quality, i.e., beneficial effects for the nonsmokers, detrimental effects for the smokers. Exposure of spermatozoa from the nonsmokers to SP from the smokers resulted in a significant reduction in sperm viability. However, exposure of spermatozoa from the smokers to SP from the nonsmokers or to Ham's F-10 medium yielded significant improvements in sperm viability. CONCLUSION(S): The detrimental effects of smokers' SP on nonsmokers' spermatozoa was prominent and a rather unique phenomenon. The results generated in this study could be of clinical significance since removal of smokers' SP and subsequent reconstitution and incubation in physiological media seems to enhance the viability, longevity, and possibly the fertilizing ability of these spermatozoa for use in various assisted reproductive technologies.

An electron microscope study of the axonemal ultrastructure in human spermatozoa from male smokers and nonsmokers.

OBJECTIVE: To investigate possible abnormalities or deterioration of the sperm axonemal ultrastructure in men who have smoked a large quantity of cigarettes (> 20 per day) for a prolonged period. DESIGN: Semen specimens were collected by patients via masturbation; qualitative characteristics of the sperm were assessed and ultrastructural analysis of the sperm axoneme was performed using standard operating procedures for electron transmission microscopy. SETTING: The Andrology Institute of Lexington, Lexington, Kentucky, and the Department of Histology and Embryology, University of Salonika, Greece (collaborative effort). PATIENT(S): Twenty-nine men (mean age +/- SD, 30.7 +/- 2.1 years) who smoked a mean (+/- SD) of 30.7 +/- 2.1 cigarettes per day for 10.7 +/- 0.7 years and 15 men who never smoked (mean age +/- SD, 30.4 +/- 2.2 years) participated in this study. MAIN OUTCOME MEASURE(S): Ultrastructural organization of the sperm axoneme in male smokers and nonsmokers. RESULT(S): Changes in the number and the arrangement of axonemal microtubules were noted in the smoker group when compared to the nonsmoker group. The incidence of axonemal abnormalities was higher in spermatozoa from smokers compared with that in spermatozoa from nonsmokers. CONCLUSION(S): Smoking a large quantity of cigarettes per day, under the conditions of the current study, severely affected the ultrastructure of the flagellum and, more specifically, it affected the axoneme of the human spermatozoon.