Molecular profile of urine extracellular vesicles from normo-functional kidneys reveal minimal differences between living and deceased donors.

BACKGROUND: Kidney transplantation (KTx) is the best therapeutic approach for chronic kidney diseases leading to irreversible kidney failure. Considering the origin of the graft, several studies have reported differences between living (LD) and deceased donors (DD) in graft and patient survival. These differences seem to be related to multiple factors including, donor age and time of cold ischemia among others. Many of transplanted organs come from old-aged DDs, in which pre-transplant biopsy is recommended. However, kidney biopsy has several limitations, and there is a need to develop alternatives to assess the status of a kidney before transplantation. As the analysis of urinary extracellular vesicles (uEVs) rendered promising results as non-invasive biomarkers of kidney-related pathologies, this pilot study aimed to investigate whether profiling uEVs of LDs and DDs may be of help to assess the quality of the kidney before nephrectomy. METHODS: uEVs from 5 living donors and 7 deceased donors were isolated by size-exclusion chromatography, and their protein and miRNA content were analysed by liquid chromatography followed by mass spectrometry and next generation sequencing, respectively. Then, hierarchical clustering and venn diagrams were done with Perseus software and InteractiVenn tool. Specific EVs data bases were also used for Gene Ontology analysis. RESULTS: Next generation sequencing revealed that uEVs from DDs contained less miRNAs than LDs, but most of the DD-expressed miRNAs were shared with LDs (96%). Only miR-326 (targeting the apoptotic-related Bcl2) was found significantly over-represented in LD. Focusing on the protein content, we detected a low intra-group correlation in both types of donors. Despite these differences, hierarchical clustering of either miRNA or protein data could not identify a differential profile between LDs and DDs. Of note, 90% of transplanted patients had a functional graft after a year from KTx. CONCLUSIONS: In this pilot study we found that, in normo-functional grafts, minor differences in uEVs profile could not discriminate between LDs and DDs.

Morbidity after laparoscopic and open rectal cancer surgery: a comparative analysis of morbidity in octogenarians and younger patients.

AIM: Although the oncological adequacy of laparoscopic rectal resection (LR) appears equivalent to open resection (OR), its benefit is controversial in the elderly. The aim of this study was to investigate the influence of LR on morbidity and mortality in octogenarians. METHOD: This was a retrospective analysis of all patients who underwent rectal surgery for cancer between 2003 and 2013 in a teaching hospital. The primary aim of the study was to assess the influence of surgical approach on mortality and morbidity of rectal resection in patients ≥ 80 years old. Regression analysis was performed to control the effect of covariables on the clinical outcome. RESULTS: Of 408 patients 203 were in the LR group and 205 in the OR group including 303 (74.3%) less than 80 years and 105 (25.7%) over 80 years. The mortality was lower in the LR group compared with the OR group for patients under 80 years (0% vs 4.6%; P = 0.049) and no different in the over 80 group (11.5% vs 9.4%; P = 0.859). In younger patients, the OR group showed longer hospital stay (9 vs 7 days; P < 0.001) and more complications (44.1% vs 29.8%; P = 0.042). Medical complications were more frequent in LR group than OR group octogenarians (40.4% vs 20.8%; P = 0.009) as well as grade C anastomotic leakage (13.8 vs 10.7; P = 0.041). CONCLUSION: LR for rectal cancer showed clinical advantages in patients under 80 years and was as safe as OR in patients over 80 years, although the advantages of laparoscopic surgery were lost in the elderly group due to a higher rate of medical complications. OR may be an option in elderly patients with important comorbidities.

A quantitative ultramorphological approach for systematic assessment of sperm head regions: an example in rams.

Examination of the type and frequency of damage to the head of spermatozoa using electron microscopy can be used to evaluate the quality of differently treated sperm. This report describes a systematic approach based on 29 morphological categories of sperm heads assessed from discrete regions in raw, chilled and frozen-thawed spermatozoa. Injury occurred principally at the plasma membrane and could be present or absent in all regions. In the anterior segment, when the plasma membrane is present, it can be intact, dilated, very dilated, disrupted, or contain vesicles characteristic of acrosomal reaction-like capacitation changes. When the plasma membrane is absent, the acrosome may be intact, exhibit a complete loss of contents, or retain some contents of the apical ridge and present a very dilated outer acrosomal membrane. The plasma membrane in the equatorial segment and the boundary between regions can be intact, dilated, very dilated or disrupted. The post-acrosomal plasma membrane is classified as intact, dilated or very dilated, whereas the dense lamina is intact, dilated or fragmented. The morphology of the heads most frequently observed in chilled spermatozoa consists of anterior and equatorial segments with a dilated, or dilated and disrupted plasma membrane; a boundary between regions with an intact and dilated plasma membrane; and a post-acrosomal region with an intact plasma membrane and dense lamina, both dilated. In frozen-thawed spermatozoa, the morphology of the heads is more frequently characterised by no plasma membrane and an acrosome showing complete or some loss of contents in the apical ridge and very dilated outer acrosomal membrane, presenting mostly dilated and fragmented dense lamina in the post-acrosomal region. These findings are consistent with the conclusion that the freezing process produces an increase in the degree of damage to the cells when they are subjected to increasing degrees of cold shock. There are still difficulties in developing a good diluent and process for preserving the plasma membrane in ram spermatozoa. This systematisation, using different categories, allows characterisation of multiple transmission electron microscopy images. Thus, the different changes observed due to cryopreservation may be correlated.

Jejunal diverticula causing massive intestinal bleeding.

Small bowel diverticula are rare formations and some are prone to complications such as lower gastrointestinal bleeding. We report the case of a patient with hemorrhagic shock following upper gastrointestinal bleeding. A 39-year-old patient was admitted to the unit for recurrent bleeding. The patient received transfusions and selective arteriography was performed which reported bleeding at the level of the ileocolic artery. Laparatomy was performed and blood was found at the entire colon and small intestine up to 40 cm of Treitz angle where multiple diverticula were visualized. Bowel resection was performed. Although duodeno-jejunal diverticula are rare, a special attention should be paid to this clinical entity as it can be a cause of recurrent upper gastrointestinal bleeding.

Use of images in a surgery consultation. Will it improve the communication?

INTRODUCTION: The interviews and interactions with patients are part of everyday health care provider. However, there is sometimes a difficulty in communication, linked to several factors. For this reason, the use of images to illustrate the medical conditions in the outpatient clinic can improve patient communication. We report our initial experience with the use of images to manage the quality of care to surigcal patients. METHODOLOGY: He used a computer to show pictures of the following conditions: surgery for an inguinal hernia, cholelithiasis, cholecystitis and the choledocholithiasis and finally thyroid pathology. Were randomized two groups of patients. Each of the affected patients in any stage of the disease, they explained their problems. In one of the groups also showed the patient was using the current image and continued to give appropriate explanations related to pathology. Thereafter, patients in both groups filled in an anonymous questionnaire in which they responded to what degree it was considered useful this methodology, and degree of satisfaction received outpatient treatment with or without the deployment of images by computer. We have analyzed the average time expected and made a visit. RESULTS: 187 patients will be visited in the consultations over a period of 8 months. In 83 patients have been using images to give the explanations in external consultations. Of these, 24 patients suffering from thyroid, 24 hernias or incisional hernias and 35 patients with biliary tract pathology. Patients in the group were shown images of conditions have responded mostly be very satisfied with the use of images while the explanations are given on the patient's illness. Also, over 80% of patients report being satisfied with this system. The visiting time was not lengthened. DISCUSSION: Despite the existence of different variables that can influence patient satisfaction, use of images to illustrate surgical diseases to patients improves communication and flow of the explanations of the physician. CONCLUSIONS: The relationship doctor-patient communication is the key event in an outpatient setting. It determines a good overall result of the clinical interview. The use of images in an outpatient improves communication between patients and doctors. Moreover, the degree of satisfaction is high and the degree of understanding of the disease. It seems useful to incorporate in our outpatient clinic.

Use of a bioabsorbable mesh in midline laparotomy closure to prevent incisional hernia: randomized controlled trial.

INTRODUCTION: The objective was to assess the effectiveness and safety of a bioabsorbable mesh at the time of closure of a midline laparotomy for IH prevention. MATERIALS AND METHODS: A multicenter, randomized clinical trial including patients undergoing abdominal surgical procedures through a midline laparotomy incision was designed. In the group of mesh (n = 167) the incision was closed using a continuous polydioxanone suture (PDS) plus a bioabsorbable mesh. In the control group (n = 165) a continuous PDS single layer suture was only used. Patients were randomly assigned (1:1) to the two groups. The primary outcome was the incidence of IH at 6, 12 and 24 months. Assessment of IH was done using a CT scan. RESULTS: At 6 months, the rates of IH were 15.2% and 24.8% in the experimental and control groups, respectively (relative risk [RR] 0.66, 95% confidence interval [CI] 0.38-0.98, P = 0.042). At 12 months, the rate of IH continued to be significantly lower in the experimental group (21.4% vs. 33.1%, P = 0.033), but at 24 months, there were no significant differences between the study groups with a follow-up rate of only 37.5%. The number needed to treat (NNT) was 11 and 9 at 6 and 12 months, respectively. CONCLUSION: The bioabsorbable mesh significantly prevented IH during the first year. Not reliable conclusions can be drawn across the second year. This may suggest that the any of the closing technique assessed in this study would have a "palliative" transient effect for preventing IH in the long-term.

Is Sarcopenic Obesity an Indicator of Poor Prognosis in Gastric Cancer Surgery? A Cohort Study in a Western Population.

BACKGROUND: The prognostic value of sarcopenic obesity in gastric cancer surgery remains debated. We aimed to evaluate the impact on outcomes of body composition and sarcopenic obesity after gastrectomy for gastric cancer. METHODS: A retrospective review of prospectively maintained database of patients undergoing gastrectomy for gastric cancer from 2010 to 2017 was performed. Skeletal muscle mass and visceral adipose tissue were evaluated by preoperative computed tomography to define sarcopenia and obesity. Patients were classified in body composition groups according to the presence or absence of sarcopenia and obesity. Prognostic factors for survival were assessed by multivariate Cox analysis. RESULTS: Of the 198 patients undergoing gastrectomy for gastric cancer, 90 (45.4%) patients were sarcopenic, 130 (67.7%) obese, and in the subclassification for body composition categories: 33 (17%) nonsarcopenic nonobesity, 75 (38%) non sarcopenic obesity, 35 (17%) sarcopenic nonobesity, and 55 (28%) sarcopenic obesity. No category of body composition was a predictor of postoperative complications and worse overall and disease-free survival outcomes. Multivariable analysis identified ASA III classification, preoperative weight loss > 10%, postoperative surgical re-intervention, and advanced tumor stage as independent prognostic factors for overall survival, and patients aged 75 years or older, preoperative weight loss > 10%, elevated netrophil-lymphocyte ratio, and advanced tumor stage as independent prognostic factors for disease-free survival. CONCLUSIONS: Sarcopenia, obesity, and sarcopenic obesity were not associated with worse outcomes after gastric cancer surgery.

Single incision laparoscopic surgery (SILS) cholecystectomy. A novel technique.

INTRODUCTION: Since early nineties, laparoscopic cholecystectomy has become gold standard for cholecystectomy. Also, a high tendency of minimizing surgical trauma encourages the use of new approaches in laparoscopic surgery. A novel approach such as Single incision laparoscopic surgery (SILS) cholecystectomy has been describes. CASE REPORT: We report on a case of a 33-year-old female patient scheduled for elective laparoscopic cholecystectomy due to symptomatic ultrasonography verified cholelithiasis. A single 2.5-cm long semicircular infraumbilical skin incision was used. Pneumoperitoneum was established alter introduction of the predesigned trocar. Antegrade cholecystectomy was performed without stay suture placement. Postoperative course was uneventful. DISCUSSION: This article reports the authors' method of performing SILS cholecystectomy. SILS approach is feasible with new standard devices from the industry that offers slightly modified instruments for standard laparoscopic cholecystectomy. CONCLUSION: Single-incision laparoscopic surgery is a feasible way to perform cholecystectomy. A learning-curve is required and further work in the form of randomized controlled trials is needed to investigate the advantages of this new technique.

Exploratory study on microRNA profiles from plasma-derived extracellular vesicles in Alzheimer's disease and dementia with Lewy bodies.

BACKGROUND: Because of the increasing life expectancy in our society, aging-related neurodegenerative disorders are one of the main issues in global health. Most of these diseases are characterized by the deposition of misfolded proteins and a progressive cognitive decline. Among these diseases, Alzheimer's disease (AD) and dementia with Lewy bodies (DLB) are the most common types of degenerative dementia. Although both show specific features, an important neuropathological and clinical overlap between them hampers their correct diagnosis. In this work, we identified molecular biomarkers aiming to improve the misdiagnosis between both diseases. METHODS: Plasma extracellular vesicles (EVs) -from DLB, AD and healthy controls- were isolated using size-exclusion chromatography (SEC) and characterized by flow cytometry, Nanoparticle Tracking Analysis (NTA) and cryo-electron microscopy. Next Generation Sequencing (NGS) and related bibliographic search was performed and a selected group of EV-associated microRNAs (miRNAs) was analysed by qPCR. RESULTS: Results uncovered two miRNAs (hsa-miR-451a and hsa-miR-21-5p) significantly down-regulated in AD samples respect to DLB patients, and a set of four miRNAs (hsa-miR-23a-3p, hsa-miR-126-3p, hsa-let-7i-5p, and hsa-miR-151a-3p) significantly decreased in AD respect to controls. The two miRNAs showing decreased expression in AD in comparison to DLB provided area under the curve (AUC) values of 0.9 in ROC curve analysis, thus suggesting their possible use as biomarkers to discriminate between both diseases. Target gene analysis of these miRNAs using prediction online tools showed accumulation of phosphorylation enzymes, presence of proteasome-related proteins and genes involved in cell death among others. CONCLUSION: Our data suggest that plasma-EV associated miRNAs may reflect a differential profile for a given dementia-related disorder which, once validated in larger cohorts of patients, could help to improve the differential diagnosis of DLB versus AD.

High EPHB2 mutation rate in gastric but not endometrial tumors with microsatellite instability.

The EPH/EFN family of receptor tyrosine kinases regulates cell adhesion and migration and has an important role in controlling cell positioning in the normal intestinal epithelium. Inactivation of EPHB2 has recently been shown to accelerate tumorigenesis in the colon and rectum, and we have previously demonstrated frequent frameshift mutations (41%) in an A9 coding microsatellite repeat in exon 17 of EPHB2 in colorectal tumors with microsatellite instability (MSI). In this study, we extended these analyses to extracolonic MSI cancers, and found frameshift EPHB2 mutations in 39% (25/64) of gastric tumors and 14% (8/56) of endometrial tumors. Regression analysis of these EPHB2 mutation data on the basis of our previously proposed statistical model identified EPHB2 as a selective target of frameshift mutations in MSI gastric cancers but not in MSI endometrial carcinomas. These results suggest a functional role for EPHB2 in gastric tumor progression, and emphasize the differences between the tumorigenic processes in MSI gastrointestinal and endometrial cancer.

Influx of recent thymic emigrants into autoimmune thyroid disease glands in humans.

Autoimmune thyroid diseases (AITD) are considered as prototypic organ-specific autoimmune diseases, yet their underlying aetiology remains poorly understood. Among the various pathophysiological mechanisms considered, a failure of central tolerance has received little attention. Here we present evidence in favour of dysregulated thymic function playing a role in AITD. Flow-cytometric analyses conducted in peripheral blood lymphocytes from 58 AITD patients and 48 age- and-sex-matched controls showed that AITD patients have significantly higher blood levels of CD4(+)CD45RA(+), CD4(+)CD31(+) and CD4/CD8 double-positive T lymphocytes, all markers of recent thymic emigrants (RTE). In addition, the alpha-signal joint T cell receptor excision circles (TRECs) content (a molecular marker of RTEs) was higher in the group of AITD patients older than 35 years than in age-matched controls. This was independent from peripheral T cell expansion as assessed by relative telomere length. Comparisons of TREC levels in peripheral blood lymphocytes and intrathyroidal lymphocytes in paired samples showed higher levels within the thyroid during the initial 30 months of the disease, indicating an influx of RTE into the thyroid during the initial stages of AITD. Additionally, a lack of correlation between TREC levels and forkhead box P3 expression suggests that the intrathyroidal RTE are not natural regulatory T cells. These results uncover a hitherto unknown correlation between altered thymic T cell export, the composition of intrathyroidal T cells and autoimmune pathology.

Short postal questionnaire and selective clinical examination combined with repeat mailing and telephone reminders as a method of follow-up in hernia surgery.

BACKGROUND: We assessed the usefulness of a short postal questionnaire and selective clinical examination combined with repeat mailing and telephone reminders for quality assessment in hernia surgery. METHODS: All patients (n = 1153) who underwent tension-free hernioplasty through an open preperitoneal approach between 1999 and 2003 received a six-item questionnaire with a covering letter and a stamped addressed envelope. Nonresponders received two successive new questionnaires and a telephone call. RESULTS: A total of 841 (72.9%) patients returned questionnaires after three reminders (512 after the first mailing, 205 after the second, and 124 after the third). Positive questionnaire answers were documented for 152 (18.1%) of repairs and negative answers for 689 (81.9%). Of the 152 patients who answered "yes" to either of the questions regarding recurrence and/or current pain, 91 declined clinical appointments, 24 could not be contacted by phone, and 37 underwent physical examination. Of the 312 patients who did not return the questionnaire, eight had died, 124 did not want to be visited, and 180 could not be located. The recurrence rate was 2.7% and the chronic pain rate 5.9%. CONCLUSIONS: Repeat mailing was a useful strategy to improve response to self-administered postal questionnaires on hernia surgery quality assessment. However, contacting the group that responded with positive questionnaire answers was a poorly effective way to encourage subjects to come for a physical examination.

Improved surgical mesh integration into the rat abdominal wall with arginine administration.

Prosthetic meshes are used as the standard of care in abdominal wall hernia repair. However, hernia recurrences and side effects remain unsolved problems. The demand by health care providers for increasingly efficient and cost-effective surgery encourages the development of newer strategies to improve devices and outcomes. Here, we evaluated whether l-arginine administration was able to ameliorate long-term polypropylene prostheses incorporation into the abdominal wall of Sprague-Dawley rats. Meshes were placed on-lay and continuous l-arginine was administered. In vivo biocompatibility was studied at 7, 25 and 30 days post-implantation. Effectively, l-arginine administration in combination with mesh triggered subtle changes in ECM composition that impinged on critical biochemical and structural features. Lastly, tensile strength augmented and stiffness decreased over the control condition. This could help to restructure the mechanical load transfer from the implant to the brittle surrounding tissues, i.e., impact load and fatigue load associated with mechanical tensions could be distributed between the mesh and the restored tissue in a more balanced manner, and ultimately help to reduce the incidence of loosening, recurrences, and local wound complications. Since the newly formed tissue is more mechanically stable, this approach could eventually be introduced to human hernia repair.

Somatic mutations in the DNA damage-response genes ATR and CHK1 in sporadic stomach tumors with microsatellite instability.

Maintenance of genomic stability depends on the appropriate cellular responses to DNA damage and the integrity of the DNA repair systems. We analyzed stomach tumors with microsatellite instability (MSI) for frameshift mutations in several potential targets of the mutator phenotype involved in DNA damage-response pathways, such as the ataxia telangiectasia mutated protein-related protein (ATR)-CHK1-Cdc25c pathway, and DNA repair. High frequency of mutations was found within ATR [5 (21%) of 23], MED1 [10 (43%) of 23], hMSH3 [13 (56%) of 23], and hMSH6 [10 (43%) of 23] genes. Also, a low frequency of mutations within the CHK1 gene was detected in 9% (2 of 23) of tumors. No mutations of hMLH3, ATM, BRCA1, or NBS1 genes were detected. These results confirm ATR, MED1, and CHK1 as targets of the mutator pathway in stomach tumorigenesis, and also suggest a potential role of MED1 increasing, together with hMSH3 and hMSH6, the genomic instability in the mutator pathway as a secondary mutator. Furthermore, these results suggest that the inhibition of the ATR-CHK1 DNA damage-response pathway might be involved in the tumorigenesis of gastric cancer with microsatellite instability.

Expression of transporter associated with antigen processing-1 in the endocrine cells of human pancreatic islets: effect of cytokines and evidence of hyperexpression in IDDM.

A possible role of transporter associated with antigen processing (TAP)-1 in the pathogenesis of IDDM has been investigated by examining the level of TAP-1 expression in the islets of IDDM pancreas and by studying in vitro the effect of interferon (IFN)-gamma, IFN-alpha, and tumor necrosis factor-alpha in TAP-1 expression by cultured islet cells. A remarkable hyperexpression of TAP-1 has been found in the endocrine cells (beta and non-beta) of IDDM islets, which constitutes first evidence of hyperexpression of this molecule in the target organ of an autoimmune disease. TAP-1 hyperexpression correlated clearly with HLA class I hyperexpression but only very partially with HLA class II ectopic expression. IFN-gamma and IFN-alpha, both cytokines putatively implicated in IDDM pathogenesis, were capable of inducing TAP-1 protein (as assessed by immunofluorescence flow cytometry) and message (by Northern blot analysis and reverse transcription polymerase chain reaction). These findings suggest that under the influence of cytokines (most probably IFN-alpha) beta-cells may express in their surface a high density of HLA class I-peptide complexes that may facilitate their recognition and lysis by low-affinity CD8+ T-cells.

BRAF screening as a low-cost effective strategy for simplifying HNPCC genetic testing.

BACKGROUND: According to the international criteria for hereditary non-polyposis colorectal cancer (HNPCC) diagnostics, cancer patients with a family history or early onset of colorectal tumours showing high microsatellite instability (MSI-H) should receive genetic counselling and be offered testing for germline mutations in DNA repair genes, mainly MLH1 and MSH2. Recently, an oncogenic V600E hotspot mutation within BRAF, a kinase encoding gene from the RAS/RAF/MAPK pathway, has been found to be associated with sporadic MSI-H colon cancer, but its association with HNPCC remains to be further clarified. METHODS: BRAF-V600E mutations were analysed by automatic sequencing in colorectal cancers from 206 sporadic cases with MSI-H and 111 HNPCC cases with known germline mutations in MLH1 and MSH2. In addition, 45 HNPCC cases showing abnormal immunostaining for MSH2 were also analysed. RESULTS: The BRAF-V600E hotspot mutation was found in 40% (82/206) of the sporadic MSI-H tumours analysed but in none of the 111 tested HNPCC tumours or in the 45 cases showing abnormal MSH2 immunostaining. CONCLUSIONS: Detection of the V600E mutation in a colorectal MSI-H tumour argues against the presence of a germline mutation in either the MLH1 or MSH2 gene. Therefore, screening of these mismatch repair (MMR) genes can be avoided in cases positive for V600E if no other significant evidence, such as fulfilment of the strict Amsterdam criteria, suggests MMR associated HNPCC. In this context, mutation analysis of the BRAF hotspot is a reliable, fast, and low cost strategy which simplifies genetic testing for HNPCC.

Effects of glycerol and sugar mixing temperature on the morphologic and functional integrity of cryopreserved ram sperm.

Sperm deep freezing procedures for ram semen have considerable variations regarding the steps being employed for cooling, freezing, and addition of cryoprotectants. In this work, we evaluated the effects of the addition of glycerol and/or the disaccharides sucrose and trehalose to hypertonic diluents either before or after cooling from 30 °C to 5 °C in Merino Australian ram semen cryopreservation. Using optical and transmission electron microscopy techniques, we assessed that glycerol was beneficial to the cooling process independently of its addition at 30 °C or 5 °C in terms of sperm membrane integrity in different regions of the plasma membrane (acrosomal region, 14.5% higher integrity; postacrosomal region, 8.0% higher integrity [P < 0.01]; hypoosmotic swelling test [HOST], 10.8% higher integrity [P < 0.001]). Disaccharides were necessary for a better cryopreservation in liquid nitrogen, and the best procedure was their addition after cooling at 5 °C (12% higher sperm motility [P < 0.001]; 8% higher acrosome integrity, [P < 0.05]; 9.5% higher plasma membrane integrity assessed by HOST [P < 0.001]). Trehalose showed a greater preservation cryoprotectant capacity than sucrose, as indicated by sperm motility after thawing (8.1% greater [P < 0.01]) and by the integrity of the intermediate piece (20% greater [P < 0.05]). From these results, we conclude that the best procedure for ram semen cryopreservation in hypertonic disaccharide-containing diluents is the addition of glycerol and trehalose after the cooling process, at 5 °C.

Sperm head ellipticity as a heat stress indicator in Australian Merino rams (Ovis aries) in Northern Patagonia, Argentina.

In Northern Patagonia, Argentina, the ovine mating season starts on March 15, which is the time when rams are submitted to summer temperatures. This study assessed the adaptability of 12 Australian Merino rams, six unshorn and six shorn, half of which were treated in a heat chamber for five days (09.00 hours to 17.00 hours) that gradually reached 40 °C. In an attempt to quantify the effects of heat stress on sperm head morphology, ellipticity was analyzed to establish the relationship between the distributions of subpopulations, light hours, temperature and humidity. Ellipticity was measured on 9224 sperm heads that were obtained over 12 weeks starting in the summer time. Four sperm head subpopulations (S) were identified by comparison with a sperm head population of ejaculates obtained in the late breeding season without the effect of heat stress (S1 = heads with ellipticity ≥ 2.00; S2 = sperm head with range of ellipticity between 1.80 and 1.99; S3 = sperm head with range of ellipticity from 1.60 to 1.79; and S4 = sperm head with range of ellipticity from 1.30 to 1.59). The variable sperm head ellipticity for each ejaculate was expressed as the means and frequencies of subpopulation. The results demonstrate changes in ram sperm head ellipticity in different conditions (control/treated, unshorn/shorn) throughout the experiment (P < 0.05). Treated shorn rams had a higher mean ellipticity and frequency of elliptical heads (mean ellipticity value = 2.06 and S1 frequency = 76.35%), peaking in the seventh week posttreatment (on the basis of the action of heat stress on seminiferous tubules). According to this study, unshorn rams were better adapted to heat stress than the shorn ones.