Investigation Of Possible Causes Research Articles

Abstract B010: Racial and ethnic differences in response to neoadjuvant chemotherapy and the impact on overall survival among early-stage ERBB2-low breast cancer patients

Abstract Background: Recent studies have reported a pathologic complete response (pCR) rate of 13.0-36.3% in patients (pts) with early-stage human epidermal growth factor receptor-2 (ERBB2 [formerly HER2])-low breast cancer after neoadjuvant chemotherapy (NACT), however, have found contradicting results comparing survival outcomes between pts with ERBB2-low and pts with ERBB2-0 tumors. Further, racial/ethnic differences in pCR, and in overall survival (OS) by pCR status, among early-stage ERBB2-low breast cancer pts after NACT are unknown. Methods: We analyzed data from early-stage ERBB2-low breast cancer pts in the 2010-2020 National Cancer Database, a joint project of the Commission on Cancer of the American College of Surgeons and the American Cancer Society. Racial/ethnic groups included Asian/Pacific Islander (API), American Indian/Alaska Native (AIAN), Black, Hispanic, and White. ERBB2-low was defined as having an IHC score of 1+ or 2+, without gene amplification by FISH. pCR (ypT0/Tis ypN0) status was dichotomized as “achieved/did not achieve,” modeled using multivariable logistic regression. OS, measured from the surgery date to the date of death or the last contact, was modeled using multivariable Cox proportional hazard regression by pCR status. Results: Of 25,577 pts (mean age 54 years [SD=12]), most (66.0%) were White, followed by 18.0% Black, 9.1% Hispanic, 5.1% API, and 1.8% AIAN. Overall, 15.2% achieved pCR. Black pts achieved a 17.4% pCR rate, Hispanic 16.0%, White 14.7%, API 13.5%, and AIAN 10.9%. After adjusting for clinicopathological characteristics, AIAN pts had lower odds of pCR achievement than White pts (adjusted odds ratio [AOR]=0.66, 95% CI: 0.48-0.91). There were no statistically significant differences in the odds of pCR achievement between Hispanic and White pts (AOR=1.12, 95% CI: 0.98-1.29), between Black and White pts (AOR=1.01, 95% CI: 0.92-1.12), or between API and White pts (AOR=0.95, 95% CI: 0.79-1.14). Among pts who did not achieve pCR, API (adjusted hazard ratio [aHR]=0.62; 95% CI: 0.51-0.76) and Hispanic (aHR=0.77, 95% CI: 0.67-0.89) pts had a significantly lower risk of death than White pts; mortality risk was marginally statistically significant comparing Black with White pts (aHR=1.07, 95% CI:1.00-1.17) and was not statistically significant comparing AIAN with White pts (aHR=0.88, 95% CI: 0.65-1.18). Among pts who achieved pCR, we did not observe statistically significant differences in the risk of death between Hispanic and White pts (aHR=1.08, 95% CI: 0.66-1.78), between Black and White pts (aHR=0.77, 95% CI: 0.55-1.09), between API and White pts (aHR=0.41, 95% CI: 0.15-1.12), or between AIAN and White pts (aHR=0.35, 95% CI: 0.05-2.50). Conclusions: In this large national cohort of pts with early-stage ERBB2-low breast cancer, post-NACT pCR was highest in Black and lowest in AIAN pts. Compared with White pts, only AIAN pts showed significantly lower odds of achieving pCR. Our findings suggest further investigation of possible causes of racial/ethnic OS differences after NACT in this patient population. Citation Format: Jincong Q. Freeman, James L. Li, Olasubomi Omoleye. Racial and ethnic differences in response to neoadjuvant chemotherapy and the impact on overall survival among early-stage ERBB2-low breast cancer patients [abstract]. In: Proceedings of the 16th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2023 Sep 29-Oct 2;Orlando, FL. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2023;32(12 Suppl):Abstract nr B010.

Investigation of possible causes of ionospheric anomalies pre/post-earthquakes based on space weather conditions (SWC)

Investigation of possible causes of ionospheric anomalies pre/post-earthquakes based on space weather conditions (SWC)

Seasonal Fluctuations in Nitrate Levels Can Trigger Lead Solder Corrosion Problems in Drinking Water.

After a utility switched its source water from ground to surface water in 2017, first draw water lead levels spiked due to increased lead solder corrosion that could not be explained by existing knowledge. When lead release was not adequately reduced with a 90:10 orthophosphate/polyphosphate corrosion inhibitor blend or even high levels of 100% orthophosphate, an in-depth investigation of possible causes revealed a strong correlation between 90th percentile lead and seasonal fluctuations in surface water nitrate levels. Complementary bench-scale studies that tested new copper coupons with lead solder and harvested pipes from a worst case home verified a strong relationship between nitrate and elevated lead. Lead release in the presence of nitrate became increasingly erratic with time, resulting in the spalling of large lead solder particulates up to 7 mm in length into the water. Lead levels were occasionally >1000 ppb in homes and >100000 ppb in the bench experiments with harvested pipe. Orthophosphate was unable to sufficiently reduce lead levels below the action level during periods with high nitrate levels in the bench studies. Water utilities and regulators should proactively consider possible unintended consequences of higher nitrate levels on lead release when changing source waters or during seasonal runoff events.

Drug Sensitivity of Vaccine-Derived Rubella Viruses and Quasispecies Evolution in Granulomatous Lesions of Two Ataxia-Telangiectasia Patients Treated with Nitazoxanide.

A strong association between rubella virus (RuV) and chronic granulomas, in individuals with inborn errors of immunity, has been recently established. Both the RA27/3 vaccine and wild-type RuV strains were highly sensitive to a broad-spectrum antiviral drug, nitazoxanide (NTZ), in vitro. However, NTZ treatment, used as a salvage therapy, resulted in little or no improvements of RuV-associated cutaneous granulomas in patients. Here, we report investigations of possible causes of treatment failures in two ataxia-telangiectasia patients. Although a reduction in RuV RNA in skin lesions was detected by real-time RT-PCR, live immunodeficiency-related vaccine-derived rubella viruses (iVDRV) were recovered from granulomas, before and after the treatments. Tizoxanide, an active NTZ metabolite, inhibited replications of all iVDRVs in cultured A549 cells, but the 50% and 90% inhibitory concentrations were 10–40 times higher than those for the RA27/3 strain. There were no substantial differences in iVDRV sensitivities, neither before nor after treatments. Analysis of quasispecies in the E1 gene, a suspected NTZ target, showed no effect of NTZ treatments on quasispecies’ complexity in lesions. Thus, failures of NTZ therapies were likely due to low sensitivities of iVDRVs to the drug, and not related to the emergence of resistance, following long-term NTZ treatments.

Pesticide mixture toxicity assessment through in situ and laboratory approaches using embryo-larval stages of the pacific oyster (Magallana gigas)

Worsened state of oysters in French Arcachon Bay, demand an investigation of possible causes. This study evaluated the effects of an environmentally relevant mixture of five common pesticides on the early-life stages of the Pacific oyster (Magallana gigas). Laboratory assays with artificial mixture and in situ transplantation were complementarily used to investigate a series of sublethal endpoints. The laboratory exposure revealed developmental toxicity at 0.32 μg/L, which corresponds to mixture concentrations in Arcachon Bay. Downregulation of some gene transcriptions was observed at environmental level. No difference in larvae development was revealed among the three sites in Arcachon Bay. This study was the first to evaluate locomotion of oyster larvae exposed in situ. Suspected poor water quality in the inner part of Arcachon Bay was reflected by impairment at the molecular level. In conclusion, current concentrations of the tested pesticides in Arcachon Bay hinder larval development and affect several biological functions.

Increased colon transit time and faecal load in irritable bowel syndrome.

BACKGROUNDIrritable bowel syndrome (IBS) is a bowel disorder involving abdominal pain or discomfort along with irregularity of stool form and passage frequency. The pathophysiology is poorly understood and seems to be multifactorial. Investigations of possible causes of IBS have included only a few colonic transit studies and no simultaneous determination of the colonic faecal content.AIMTo compare colon transit time and faecal load between IBS-patients and healthy control subjects. METHODSThe study included 140 patients with IBS, with a mean age of 50.0 years. The control group comprised 44 healthy persons with a mean age of 43.4 years, who were selected at random from the National Civil Register. Both the patient group and the control group underwent a marker study to measure colon transit time (CTT) and to calculate a faecal loading score. The patient group underwent treatment with a combined prokinetic regime, after which their CTT and faecal loading were reassessed. Analyses were performed to compare measurements between the control group and the patient group before and after treatment.RESULTSCompared to healthy controls, IBS-patients exhibited a significantly prolonged mean CTT (45.48 h vs 24.75 h, P = 0.0002) and significantly greater mean faecal loading scores in all colonic segments (P < 0.001). Among IBS patients, we found no significant differences between the 48 h and 96 h radiographs. Among patients exhibiting increased CTT and faecal loading, approximately half exhibited a palpable mass in the right iliac fossa. After intervention with a prokinetic treatment, the mean CTT among IBS patients was reduced from 45.48 h to 34.50 h (P = 0.091), with the post-treatment CTT not significantly differing from the CTT among control subjects (P = 0.095). The faecal loading score among IBS patients did not significantly differ before and after treatment (P = 0.442). The post-treatment faecal loading score in IBS patients remained significantly higher compared to that in controls (5.3 vs 4.3, P = 0.014). After treatment, half of the IBS-patients were relieved of bloating, while the majority no longer experienced abdominal pain and achieved a daily consistent stool. CONCLUSIONIBS-patients exhibited prolonged CTT and heavier faecal loading. These assessments may aid in diagnosis. Faecal retention may contribute to IBS symptoms, which can be treated using a prokinetic regime.

Geo-Electric Assessment of Kali Failed Dam Project Aliero, North Western Nigeria

An integrated geophysical investigation using very low frequency electro-magnetic (VLF-EM) and electrical resistivity methods using (VES) technique has been carried out for investigation of possible causes of dam failure in Kali, Aliero Northwestern Nigeria. A total of Three 3 (VLF-EM) traverses and Ten 10 vertical electrical soundings (VES) techniques have been carried out to identify the fracture zones, seepage and possible threat that lead to the collapse of the dam. The interpretation of VLF-EM data is carried out qualitatively using Fraser and Karous-Hjelt filters and the interpretation of sounding data is done using IPI2 win software. VLF-EM data signifies the exact fracture zones founded on higher values of relative current density that coincide to the subsurface fracture. The survey was conducted on an interval of 10 m interval along traverses at South-North direction ranging from 620 - 640 m in length. The plot of filtered real and filtered imaginary identified noticeable fracture zone close to the surface which was later further delineated by (VES) technique. VES soundings were carried out at locations of prominent VLF anomalies presumably typical of basement fracture using AB/2 of 80 m. Results interpreted show layers thickness and their corresponding resistivity, top soil (0.5 m to 3.45 m, 51.9 Ωm to 318 Ωm), underlain by clay to confined clay (4.56 m to 54 m, 7.88 Ωm to 60.2 Ωm) which is underlain by fractured/fresh basement (5.76 m to 73.9 m, 40.3 Ωm to 197 Ωm). The overburden materials underlain are far away to subsurface (bed rock) in most of the area to support the dam. The clay materials which could serve as conduit, exist within the shallow overburden which was not excavated during the construction. Therefore it was concluded that the dam cannot retain its strength to oppose the dam against collapse.

Germanium and solid sample digestion with aqua regia: the nescience of chemistry basics and its sequels

The role of germanium in technology is steadily growing in importance, bringing in its wake an increased attention to its concentration and behaviour in the environment. A recent study on European agricultural soils reported that only 1% of Ge in soils was released when treated with aqua regia, a rather surprising result. The investigation of possible causes showed that huge Ge losses, as were observed in the aforementioned study, are likely to result when the sample is digested in an open system, because of the well-known volatility of the GeCl4 formed. Our study also reveals that, when working in a semi-closed system, replacement of HNO3 by NaOH in the absorbing solution is needed for complete Ge recovery. The underlying rationale has been explored by calorimetry. This case shows that widely used techniques embedded in many current, accepted environmental methods, such as aqua regia extraction, cannot be applied blindly but rather require the consideration of fundamental chemical knowledge.

Investigation of possible causes of sinkhole incident at the Zonguldak Coal Basin, Turkey

The subsidence mechanism of ground surface is a complex phenomenon when multiple seam coal mining operations are carried out. Particularly, the coal mining beneath karstic formations causes a very special form of subsidence. The subsidence causes elasto-plastic deformation of the karstic layers and the collapse of cavities leads to dolinization and/or sinkhole formation. In this study, a sinkhole with a depth of 90 m and a width of 25 m formed in Gelik district within the coal-basin of Zonguldak (NW, Turkey) induced by multiple seam coal mining operations in the past has been presented as a case-history together with two-dimensional numerical simulations and InSAR monitoring. The computational results proved that the sinkhole was formed as a result of severe yielding in the close vicinity of the faults in contact with karstic formation due to multiple seam longwall mining at different levels.

The laryngocele; case presentation

Laryngocele is a rare pathology, but because of their clinical evolution and the symptoms they generate, they should always be considered as a differential diagnosis when investigating neck masses. A laryngocele is basically a herniation of the mucosa of the laryngeal ventricle (Morgagni's ventricle) arising usually from the saccular region. This herniation may remain confined to the larynx - in which case the laryngocele is internal- or expand through the thyro-hyoid membrane into the structures of the neck - thus being called an external laryngocele. Usually the laryngocele has both an internal and external component thus being a mixed laryngocele. Diagnosis of laryngoceles still relies heavily on clinical signs such as tympanism, easily depressible neck mass, indirect laryngoscopy, but is now simplified by imagistic investigations (ultrasound, CT and MRI). However, the treatment of this condition is exclusively surgical and consists of total excision of the laryngocele, as well as proper identification of the point of origin from the saccule and also the final suture of the breach in order to prevent recurrence. Investigation of possible causes of obstruction of the laryngeal ventricle should always be performed (because of the possibility of an underlying malignancy) as well as a follow-up protocol of the patient, given the risk of relapse. We present a recently diagnosed case of a 32 year old man with mixed laryngocele, which we have operated in our clinic.

Investigation of possible causes of the additional torque on the yacht’s rudder

The present article deals with investigation of possible causes of the additional torque on the yacht’s rudder. One of the most important aspect for design of yachts are the symmetric conditions of all parts, which are located under water level and concentricity of the ship’s screw, rudder and keel relative to the hull. These symmetric and concentricity conditions have a major impact on the resulting dynamic properties of the ships. They have either substantial impact on the overall efficiency of installed engine and ship’s screw. As the result of poorly designed above mentioned parts, there can be an unsolicited additional torque on the yacht’s rudder and higher consumption of the fuel. Last but not least of these problems leads to poor controllability and discomfort within steering. This article is focused on the investigation of possible causes of the additional torque on the yacht’s rudder.

Orthopaedic surgeons� strategies in pharmacological treatment of fragility fractures

Fragility fractures are the most severe complications of osteoporosis and the poor mechanical properties of bone can make fixation and healing of these fracture extremely difficult. The role of orthopaedic surgeons does not end in skillful fixation of the fractures, but they have the unique opportunity to prevent complications which can negatively affect the patient's quality of life. The best practice for preventing the risk of further fractures in patients presenting fragility fractures includes fall prevention, investigation of possible causes underlying osteoporosis, attention to exercise, calcium and vitamin D supplementation as well as prescription of drugs. Actually two classes of agents can be used for their effect on fracture prevention: antiresorptive and bone forming agents. Systemic therapy reduces the risk of vertebral (30-70%) and non-vertebral fractures (12-53%), depending on agents and patients' compliance. Preclinical and clinical studies have shown that pharmacological agents involved in osteoporosis can also influence the phases of fracture repair. Preclinical studies and evidences from case reports showed a positive effect of anabolic drugs on bone healing and implant osseointegration. The interventions in the process of fracture healing had evolved from a diamond to a pentagon concept, with interactions between the mechanical environment, the local therapies, the vascularity of the fracture site, the biology of the host and the systemic therapy which has the potential to represent the fifth interaction factor. The orthopaedic surgeon plays a central role in clinical setting to evaluate the efficacy of systemic anti-fracture drugs for improving fracture repair and preventing complications.

Vertical velocity observed by Doppler lidar during cops - A case study with a convective rain event

Convective and Orographically-Induced Precipitation Study (COPS), conducted in the Black Forest region in Southern Germany and Eastern France during the summer of 2007. From the 13 June to the 16 August 2007, the National Centre for Atmospheric Science (NCAS), Facility for Ground-based Atmospheric Measurement (FGAM) 1.5 lm scanning Doppler lidar was deployed at Super Site R, Achern, in the Rhine Valley, in order to contribute to the extensive COPS observation campaign. The FGAM Doppler lidar system provides measurements of radial wind and aerosol backscatter in the layer 100–1500 m. Profiles of horizontal wind velocity are presented, these being derived from performing azimuth scans. Profiles of vertical velocity, its variance and skewness derived from the vertical scans are also presented and discussed in the paper. Knowledge of vertical velocity skewness is important for the understanding of the structure and origin of turbulent convection in the atmospheric boundary layer (ABL). The skewness of vertical velocity can provide a measure of the asymmetry in the distribution of vertical velocity perturbations within the ABL and can be estimated using the Doppler lidar. In addition, we investigate the behaviour of the boundary layer using data from the FGAM Doppler lidar and Automatic Weather Station (AWS), the University of Basilicata Raman lidar (BASIL) and the DLR’s Poldirad C-band radar. A case study event on the 6 th August 2007 is selected and investigations of possible causes of layers with positive and negative skewness are presented, along with comparisons with output from the National Center for Atmospheric Research (NCAR) Weather Research and Forecasting (WRF) model to assess the accuracy of the model output, including location and timing of rainfall onset.

What Is the Role of the Orthopaedic Surgeon in Management of Fragility Fractures?

Fragility fractures are the most prevalent trauma condition that orthopaedic surgeons face today. Osteoporosis and susceptibility to falls are the key predisposing factors. Despite evidence supporting the impact of treating osteoporosis on reducing the incidence of fragility fractures, it is often left untreated. Orthopaedic surgeons are often the first physicians to assess and treat the patient after a fragility fracture. Their role therefore does not end in the skillful fixation of the fractures, but they have a unique opportunity to ensure that preventive measures are implemented. This includes falls prevention, investigation of possible causes underlying osteoporosis, attention to diet, exercise, calcium, and vitamin D supplementation as well as prescription of anti-resorptive and anabolic medication. The need for a dedicated multidisciplinary team needs to be emphasized and therefore effective communication between the different parties is of paramount importance.

Mechanisms of degradation of DNA standards for calibration function during storage

Establishment of molecular diagnostics offering quantitative technology is directly associated with real-time polymerase chain reaction (PCR). This rapid, accurate and sensitive method requires careful execution, including reliable calibration standards. The storage of such standards is crucial to prevent nucleic acid decay and to ensure stable results using real-time PCR. In this study, a broad investigation of possible causes of DNA degradation during storage was performed, including GC-content of the fragments, long-term storage, rapid freeze-and-thaw experiments, genomic DNA and short DNA fragments of different species, the influence of shear stress and the effect of nuclease remaining after DNA isolation. Several known chemical DNA degradation mechanisms have been matched with the experimental data through a process of elimination. Protocols for practical application, as well as a theoretical model describing the underlying mechanisms of deviation of real-time PCR results due to decay of standard DNA, have been developed. Primary amines in the buffer composition, which enhance depurination of the DNA helix, and shear stress due to ice crystal formation, could be identified as major sources of interaction. This results in degradation of the standard DNA, as well as in the probability of occurrence of mismatches affecting real-time PCR performance.

A proposal for systematic investigation of reproducibility deviations in Laboratory Acoustical Measurements.

Cases have been observed in airborne sound isolation and impact noise insulation testing where apparently identical assemblies have achieved significantly different STC and/or IIC ratings, not only when tested at different test facilities but also when re‐tested in the same facility [J. LoVerde and W. Dong, J. Acoust. Soc. Am. 125, 2629 (2009); J. Acoust. Soc. Am. 123, 3504 (2008)]. Acoustical test data will be presented demonstrating several cases and showing that the deviations are significantly larger than the expected statistical variation based on the reproducibility of the test method as reported within the applicable ASTM standards. The reason(s) for the variation in these test results are unknown, and there has been no systematic investigation of possible causes. Standards committees, test laboratories, and government agencies have not shown a satisfactory level of interest in either quantifying the deviations or exploring the reasons behind them, which may be theoretical, material, and/or procedural. A protocol is presented for a se‐ries of investigations that could be performed in an acoustical testing laboratory intended to identify and quantify causes of the variations.

Kinetic Analysis of Peritoneal Fluid and Solute Transport with Combination of Glucose and Icodextrin as Osmotic Agents

Controlling extracellular volume and plasma sodium concentration are two crucial objectives of dialysis therapy, as inadequate sodium and fluid removal by dialysis may result in extracellular volume overload, hypertension, and increased cardiovascular morbidity and mortality in end-stage renal disease patients. A new concept to enhance sodium and fluid removal during peritoneal dialysis (PD) is the use of dialysis solutions with two different osmotic agents. To investigate and compare, with the help of mathematical modeling and computer simulations, fluid and solute transport during PD with conventional dialysis fluids (3.86% glucose and 7.5% icodextrin; both with standard sodium concentration) and a new combination fluid with both icodextrin and glucose (CIG; 2.6% glucose/6.8% icodextrin; low sodium concentration). In particular, this paper is devoted to improving mathematical modeling based on critical appraisal of the ability of the original three-pore model to reproduce clinical data and check its validity across different types of osmotic agents. Theoretical investigations of possible causes of the improved fluid and sodium removal during PD with the combination solution (CIG) were carried out using the three-pore model. The results of computer simulations were compared with clinical data from dwell studies in 7 PD patients. To fit the model to the low net ultrafiltration (366+/-234 mL) obtained after a 4-hour dwell with 3.86% glucose, some of the original parameters proposed in the three-pore model (Rippe & Levin. Kidney Int 2000; 57:2546-56) had to be modified. In particular, the aquaporin-mediated fractional contribution to hydraulic permeability was decreased by 25% and small pore radius increased by 18%. The simulations described well clinical data that showed a dramatic increase in ultrafiltration and sodium removal with the CIG fluid in comparison with the two other dialysis fluids. However, to adapt the three-pore model to the selected group of PD patients (fast transporters with small ultrafiltration capacity on average), the peritoneal pore structure had to be modified. As the mathematical model was capable of reproducing the clinical data, this shows that the enhanced ultrafiltration with the combination fluid is caused by the additive effect of the two different osmotic agents and not by a specific impact of the new dialysis fluid on the transport characteristics of the peritoneum.

Contrasting effects of token and type syllable frequency in lexical decision

In psycholinguistic research, there is still considerable debate about whether the type or token count of the frequency of a particular unit of language better predicts word recognition performance. The present study extends this distinction of type and token measures to the investigation of possible causes underlying syllable frequency effects. In two lexical decision experiments, we found a dissociation suggesting that the token measure of syllable frequency adequately predicts the inhibitory effect of initial syllable frequency, whereas the type measure led to facilitation, especially when the number of higher frequency syllabic neighbours was controlled for. This specific pattern of results, suggesting the involvement of two different processes in effects of syllable frequency, provides a strong constraint for current and future models of visual word recognition.

An investigation of possible causes of the holes in the condensational Venus cloud using a microphysical cloud model with a radiative-dynamical feedback

Near-infrared observations of the nightside of Venus reveal regions of high brightness temperatures. These regions of high brightness temperatures are caused by the localized evaporation of the middle and lower cloud decks, which are about 50 to 60 km above the surface of the planet. We simulate the Venus condensational middle and lower cloud deck with the University of Colorado/NASA Ames Community Aerosol and Radiation Model for Atmospheres (CARMA). Our simulated clouds have similar characteristics to the observed Venus clouds. Our radiative transfer model reproduces the observed temperature structure and atmospheric stability structure within the middle cloud region. A radiative-dynamical feedback occurs which generates mixing due to increased absorption of upwelling infrared radiation within the lower cloud region, as previously suggested by others. We find that localized variations in temperature structure or in sub-grid scale mixing cannot directly explain the longevity and optical depth of the clouds. However, vertical motions are capable of altering the cloud optical depth by a sufficient magnitude in a short enough timescale to be responsible for the observed clearings.

A computational approach to characterization of bovine sperm chromatin alterations

We describe here a computational morphology-based approach to the investigation of possible causes of chromatin alterations in sperm. A comprehensive set of state-of-the-art and geometric measures are computationally extracted from toluidine blue stained images and analyzed to infer the possible processes leading to normal and abnormal chromatin formation while seeking a possible taxonomy of chromatin alterations and their influence on sperm head morphology. Using this methodology, we have identified higher chromatin fragility at some specific points of the sperm head. Despite the lack of correlation between morphologies of sperm head and chromatin structure, four main morphological types of chromatin alterations in bull spermatozoa have been identified and their possible causes discussed.