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Biomedical subjects

A Peña

Publications and source records attributed to A Peña.

At least 37 records · Page 2Linked to original sources
PubMed2003

The posterior sagittal trans-sphincteric and trans-rectal approaches.

BACKGROUND: The posterior sagittal, transphincteric approach to treat different pelvic problems has been known since the last century. Although some surgeons have embraced it and have enthusiastically advocated it's use, it has never become an overly popular technique. The purpose of this study is to evaluate the advantages and disadvantages of the approach, both from a historical perspective and from the authors' experience. METHODS: The international literature on the subject was reviewed since 1877 up to the present date. A retrospective evaluation of the authors' experience was conducted. Specific attention was paid to the final result obtained in the treatment of the original condition, surgical complications and the effect of the surgical approach. on bowel and urinary control. RESULTS: The review included 114 patients divided into two groups. Group A included 85 patients who underwent a posterior sagittal trans-sphincteric approach. Group B included 29 patients who underwent a posterior sagittal transanorectal approach, in which the anterior wall of the rectum and the sphincter were divided. Postoperative bowel control was normal in all patients except in those whose basic condition had resulted in fecal incontinence, or who had sustained an irreversible injury prior to the operation. Urinary control was normal except in cases with pre-operative incontinence. Complications included recurrence of rectogenito-urinary fistulae in 3 cases, rectocutaneous fistula in 3 patients with Hirschsprung's disease, and 2 partial wound dehisences. CONCLUSIONS: The posterior sagittal trans-sphincteric approach represents a useful technical alternative. It seems to be particularly useful to treat complications after surgery for Hirschsprung's disease, presacral masses, acquired rectogenito-urinary fistulae and idiopathic rectal prolapse. The transanorectal approach provides excellent exposure to the posterior urethra and vagina. Bowel and urinary control are not compromised.

Adolescent↗
PubMed2003

Diffusion tensor imaging of brain tumours at 3T: a potential tool for assessing white matter tract invasion?

AIM: To determine whether diffusion tensor imaging (DTI) of brain tumours can demonstrate abnormalities distal to hyperintensities on T2-weighted images, and possibly relate these to tumour grade. MATERIALS AND METHODS: Twenty patients with histologically confirmed supratentorial tumours, both gliomas (high and low grade) and metastases, were imaged at 3T using T2-weighted and DTI sequences. Regions of interest (ROI) were drawn within the tumour, in white matter at various distances from the tumour and in areas of abnormality on DTI that appeared normal on T2-weighted images. The relative anisotropy index (RAI)-a measure of white matter organization, was calculated for these ROI. RESULTS: The abnormality on DTI was larger than that seen on T2-weighted images in 10/13 patients (77%) with high-grade gliomas. New abnormalities were seen in the contralateral white matter in 4/13 (30%) of these cases. In these high-grade tumours the RAI in areas of white matter disruption with normal appearance on T2-weighted images was reduced (0.19+/-0.04). Even excluding patients with previous radiotherapy this difference remains significant. In all non high-grade tumours (WHO grade II gliomas and metastases) the tumour extent on DTI was identical to the abnormalities shown on T2-weighted imaging and RAI measurements were not reduced (0.3+/-0.04). CONCLUSIONS: Subtle white matter disruption can be identified using DTI in patients with high-grade gliomas. Such disruption is not identified in association with metastases or low-grade gliomas despite these tumours producing significant mass effect and oedema. We suggest the changes in DTI may be due to tumour infiltration and that the DTI may provide a useful method of detecting occult white matter invasion by gliomas.

Adult↗
PubMed2003

Value of magnetic resonance imaging for the diagnosis and follow-up of haemophilic arthropathy.

An orthopaedic assessment of the joint status of seven severe haemophiliacs (mean age 12.5 y - range 8.9-15.5) on prophylactic treatment (PT) by magnetic resonance imaging (MRI) and physical examination was carried out. Median duration of PT of these patients was 84 months (range 32-107). A locally designed MRI joint score considering seven parameters (1 - joint effusion, 2 - synovial membrane thickening, 3 - haemosiderin deposits, 4 - joint cartilage injury, 5 - subchondral bone erosion, 6 - subchondral bone cysts, 7 - osteonecrosis) was used (maximum score = 13 points). MRI scans were performed in 17 joints (nine ankles, seven knees and one elbow): mean MRI scores for the affected joints was 5.1. A poor consistency between physical examination and MRI findings or the real extent of joint damage was found (Cohen kappa index 0.320). MRI is a precise non-invasive tool for the assessment of early joint cartilage and synovium pathological changes still undetectable by physical examination or conventional X-rays in the haemophilic setting.

Adolescent↗
PubMed2003

Stereotactic MR imaging for planning neural transplantation: a reliable technique at 3 Tesla?

The purpose of this study was to assess the accuracy of high field (3 Tesla) MR in target localization for stem cell transplantation. Three patients with Huntington's disease were imaged with a stereotactic frame in place for both MRI and CT. Quality assurance procedures and manual shimming were performed before each MRI study to minimize image distortion. The images were fused using multi-modality rigid body image registration software. Image fusion demonstrated the MR images to be in agreement with CT to within 1.5 mm, as assessed by measuring the coordinates of markers on the frame and on the shape and size of the lateral ventricles. Target coordinates for transplantation were selected from the MR images. Postoperative imaging confirmed accurate graft placement.

Brain Tissue Transplantation↗
PubMed2002

Communicating hydrocephalus: the biomechanics of progressive ventricular enlargement revisited.

BACKGROUND: This article investigates the physical mechanisms involved in the chronic ventricular enlargement that accompanies communicating hydrocephalus (CH)--including its normal and low-pressure forms. In particular, it proposes that this phenomenon can be explained by the combined effect of: (a) a reversal of interstitial fluid flow in the parenchyma, and (b) a reduction in the elastic modulus of the cerebral mantle. METHOD: To investigate this hypothesis, these changes have been incorporated into a finite element computer simulation of CH, in which brain tissue is idealized as a sponge-like material. The fluid pressure in the lateral ventricles and the subarachnoid space has been set to 10 mmHg, while the fluid pressure inside the parenchyma has been set to 7.5 mmHg. The elastic moduli of white and gray matter have been set to the reduced values of 1 and 5 kPa, respectively. FINDINGS: The simulation revealed a substantial ventricular distension (6.5 mm mean outward displacement), which was accompanied by the appearance of stress concentrations in the cerebral mantle. INTERPRETATION: These results support the notion that a relative reduction in intraparenchymal fluid pressure coupled with low tissue elasticity can produce both a significant ventricular enlargement and periventricular solid stress concentrations.

Biomechanical Phenomena↗
PubMed2002

Nature and extent of gastric lesions in symptomatic Chilean children with Helicobacter pylori-associated gastritis.

UNLABELLED: Chile has one of the highest rates of gastric cancer in the world and most children and adolescents in the country are colonized by Helicobacter pylori. This study assessed the nature and extent of the gastric lesions in 73 consecutive patients aged 5-17 y, referred for upper gastrointestinal endoscopy. Their H. pylori-associated gastric pathology was characterized and these data were compared with their sociodemographic status. Endoscopic assessment was normal in 43 patients while in 30 there was a variety of mucosal lesions. Sixty patients (83%) had histological chronic gastritis of the antrum and in 45 (63%) the lesions also involved the gastric corpus; 90% of patients with chronic gastritis were colonized by H. pylori. Although most of these patients had epithelial erosions and dedifferentiation of the pit epithelium, atrophy and metaplasia were not found. Patients' socioeconomic status was inversely correlated with their rate of colonization by H. pylori (p < 0.005), the frequency of gastric lesions on endoscopy (p < 0.01) and the frequency of involvement of antral and corpus mucosa by chronic gastritis (p < 0.002). This latter feature was positively correlated with age (p < 0.001). CONCLUSION: This study shows a high frequency of extensive lesions of H. pylori-associated chronic gastritis in young Chilean patients. This histological picture is consistent with the hypothesis of a H. pylori-associated progressive gastric pathology which may represent a major factor in the high local rate of gastric cancer.

Adolescent↗
PubMed2002

Differential effects of glucose and fructose on hexose metabolism in dog spermatozoa.

Incubation of dog spermatozoa with 10 mmol l(-1) glucose or fructose rapidly increased the intracellular content of glucose 6-phosphate and fructose 6-phosphate, although the effect of fructose was greater. These effects were correlated with increases in ATP, ribose 5-phosphate and glycogen contents, and in the rates of formation of L-lactate and CO2. In all cases, except for ATP and glycogen, the effect of fructose was greater than that of glucose. The total hexokinase activity of the crude extracts of dog spermatozoa was more sensitive to fructose than to glucose at lower concentrations (0.1-3.0 mmol l(-1)). Both monosaccharides induced a fast and intense increase in the overall tyrosine phosphorylation of dog spermatozoa, although their specific induced-phosphorylation patterns differed slightly. Glut 3 and Glut 5 hexose transporters were the main hexose transporters in dog spermatozoa; however, other possible SGLT family-related hexose transporters were also localized. These data indicate that, at concentrations from 1 mmol l(-1) to 10 mmol l(-1), fructose has a stronger effect than glucose on hexose metabolism of dog spermatozoa. These differences appear to be related to variations in the sensitivity of hexokinase activity. Moreover, the differential hexose metabolism induced by the two sugars had distinct effects on the function of dog spermatozoa, as revealed by the diverse patterns of tyrosine phosphorylation.

Adenosine Triphosphate↗
PubMed2001

Effects of glucose and fructose on motility patterns of dog spermatozoa from fresh ejaculates.

This study was performed to gain insight about how fructose and glucose modulate dog spermatozoa motility in the absence of other motility-modulating factors. Incubation of dog spermatozoa from fresh ejaculates in a basal medium without sugars for 60 min at 37 degrees C induced a progressive decrease in the percentage of motile spermatozoa and in some mean motility parameters, such as mean velocity (VAP), linear coefficient (LIN) and dance (DNC), and an increase in the mean frequency of head displacement (BCF). This indicates a progressive loss of linearity and an increase in oscillatory movement. Addition of 10 mM fructose prevented these effects. Incubation in a basal medium with 10 mM glucose for 60 min at 37 degrees C provoked a fast and intense decrease of LIN and a slight increase of DNC, inducing a less linear and more oscillatory mean movement. Neither fructose nor glucose modified the percentage of motile spermatozoa. The response to both sugars was dose-dependent, with differences appearing at concentrations as low as 1 mM. An analysis of the spermatozoa subpopulation placed above the 95th percentile of the whole population and a factorial analysis of the data indicated that the changes in the mean values of the motility parameters were mainly due to a specific motile subpopulation that had a strong reaction to the two sugars. Our results indicate that fructose, at concentrations from 1 to 10 mM, induced a more linear and less oscillatory motility pattern than glucose. Moreover, from our results we suggest the presence of motile dog sperm subpopulations with an increased sensitivity to fructose and glucose.

Animals↗
PubMed2001

Dissipation of racemic mecoprop and dichlorprop and their pure R-enantiomers in three calcareous soils with and without peat addition.

Two racemic herbicides, mecoprop (R,S-MCPP) and dichlorprop (R,S-DCPP), as well as their enantiopure R-forms, were incubated in three calcareous soils at 15 degrees C and 80% of their field capacity to try to elucidate their behaviour in soil and compare the dissipation rates when racemic and enantiopure compounds are used. Quantitation of pesticides is made by HPLC and the R/S ratio by GC-MS. The inactive S-enantiomer from the racemic forms persists longer than the R-forms in silt and sandy loam soils, but for shorter time in the clay loam soil. The pure R-enantiomers, both for MCPP and DCPP, after incubation in soil, are partially converted into their S-forms. In all cases, the dissipation of racemic and pure enatiomeric forms is lower in the clay loam soil than in the silt and sandy loam soils. The R-forms' peristence, in the three soils, is approximately two times lower when they are incubated alone than when they are incubated as racemic compounds. When peat is added, the persistence of these herbicides in the silt and sandy loam soils increases, while in the clay loam soil it decreases. Besides, in the clay loam soil, the enantiomeric ratio (ER) changes from its S-preferential degradation to a preferential degradation of its R-form, so an increase in the persistence of the inactive S-form occurs.

2,4-Dichlorophenoxyacetic Acid↗
PubMed2001

Proinflammatory cytokine expression in gastric tissue from children with Helicobacter pylori-associated gastritis.

BACKGROUND: Helicobacter pyloriinfection of the gastric mucosa in humans is usually acquired early in life. The chronic inflammation that ensues involves the increased production of inflammatory cytokines. Published data on production of these mediators by gastric mucosa of H. pylori-infected children are few. METHODS: Seventy-nine children, aged 5 to 18 years, referred for upper gastrointestinal endoscopy to four separate hospitals in Chile, were studied. The concentrations of interleukin (IL)-1beta, IL-6, IL-8, and tumor necrosis factor alpha were measured in homogenates of gastric mucosal biopsy specimens. Cytokine expression was confirmed by reverse transcription polymerase chain reaction. These data were correlated with the patients' clinical, histologic and sociodemographic status. RESULTS: Patient rate of colonization by H. pylori was inversely correlated with socioeconomic status (P < 0.005) and positively correlated with age (P < 0.0025). In gastric mucosa, concentrations of IL-1beta, IL-8, and tumor necrosis factor alpha were all significantly higher in H. pylori-positive patients than in H. pylori-negative patients and in patients who had histologic gastritis than in those with normal gastric mucosa. In patients with peptic ulcer disease, only IL-1beta and IL-8 concentrations were significantly elevated when compared with those of patients without ulcers. Interleukin-6 concentrations were comparable among the different groups analyzed. CONCLUSIONS: This study suggests that increased gastric mucosal production of the proinflammatory cytokines IL-1beta and IL-8 is probably involved in H. pylori-associated gastric damage in children and may be crucial in determining the different clinical outcomes.

Adolescent↗
PubMed2001

Rotavirus-associated medical visits and hospitalizations in South America: a prospective study at three large sentinel hospitals.

BACKGROUND: Knowledge of the impact of rotavirus-associated disease on the health care systems of South America can aid in defining strategies for diagnosis, management and prevention. Up to date information on the impact of rotavirus disease in South America is scarce. AIM: To determine prospectively the impact of rotavirus disease as a cause of medical visits and hospitalizations at three large sentinel pediatric hospitals in Argentina, Chile and Venezuela. METHODS: A 2-year prospective surveillance for rotavirus-associated medical visits and hospitalizations was conducted during 1997 through 1998 at three large sentinel public hospitals, one each in Argentina, Chile and Venezuela. A common surveillance protocol was implemented at the three sites, and a representative number of nonbloody diarrhea stool samples from children <36 months of age were tested for rotavirus by enzyme-linked immunosorbent assay. RESULTS: For our target age group, acute diarrhea-associated medical visits/hospitalizations represented 41%/2%, 5%/6% and 9%/13% of all medical visits/all hospitalizations at the Argentinean, Chilean and Venezuelan sites, respectively (P < 0.001 for difference among the three sites). Rotavirus detection rates among a total of 5,801/1,256 medical visit/hospitalization diarrhea stool samples tested were 39%/71% in Argentina, 34%/47% in Chile and 29%/38% in Venezuela (P < 0.01 by chi square for difference among the three sites). Rotavirus was associated with a mean of 1.5, 1.8 and 3% of total medical visits and 1.6, 2.8 and 5% of hospitalizations among children <36 months of age at the Argentinean, Chilean and Venezuelan sites, respectively. Seasonality was evident for medical visits at all three sites (although less striking in Chile) with peak activity occurring between November and May. Rotavirus-associated hospitalizations had a marked peak in Venezuela, represented largely by short stays, but not in Argentina and Chile. CONCLUSIONS: Rotavirus was a significant cause of medical visits at all three sentinel sites. Rotavirus caused less hospitalizations than previously reported in Argentina and Chile. On the basis of our findings we estimate that approximately 106,000/ 21,000, 48,000/8,000 and 98,000/31,000 rotavirus-associated medical visits/hospitalizations occur yearly in Argentina, Chile and Venezuela, respectively.

Argentina↗
PubMed2001

Outpatient management of upper digestive hemorrhage not associated with portal hypertension: a large prospective cohort.

OBJECTIVES: To evaluate the safety of outpatient management of upper GI hemorrhage (UGIH) not associated with portal hypertension. METHODS: A prospective cohort of 983 subjects who went to the Accident & Emergency Department (A&ED) of a University hospital in Valencia (Spain), for UGIH not associated with portal hypertension during 1994 to 1997 were evaluated. After evaluation in the A&ED, 216 patients (22%) were discharged and referred for outpatient follow-up, but 15 patients could not be located thus, reducing the follow-up to 201 subjects. The main outcome measures were rebleeding within 10 days, emergency surgery within 15 days, and mortality for any cause during the 30 days after the initial hemorrhaging episode. RESULTS: UGIH in subjects under outpatient care were less severe than those subjects in the hospitalized group. Hemorrhaging recurred in 7.3% of inpatients versus 0.5% of outpatients (p < 0.01); emergency surgery was required in 5.6% of the hospitalized patients and 0.5% of the outpatients (p < 0.01); a total of 20 deaths occurred in the hospitalized group (2.6%), while three (1.5%) occurred in outpatients (p = 0.26). After adjusting for several significant risk factors, outpatient management was not associated with outcomes that were worse. CONCLUSIONS: Treatment under an outpatient regime is a safe alternative for a large percentage of selected patients with UGIH not associated with portal hypertension.

Aged↗
PubMed2001

Membranous nephropathy associated with hepatitis B in Spanish children.

AIM: To examine retrospectively long-term evolution and treatment of pediatric membranous nephropathy (MN) cases associated with hepatitis B (HB) in the hospital "La Paz". MATERIAL AND METHODS: The clinical records of 12 children diagnosed with HB-associated MN in our hospital between 1970 and 1996. RESULTS: All patients were positive for hepatitis B surface antigen (HBsAg); 6 were tested for hepatitis Be antigen (HBeAg) and were also positive. At onset, all of them had proteinuria (8 in nephrotic range), 6 had microscopic hematuria and 4 macroscopic hematuria. Seven of 8 children who started with a nephrotic syndrome received steroids and all of them were steroid-resistant. After 9.95 +/- 5.88 years of follow-up, renal function remained normal and proteinuria and hematuria have disappeared in all of them. A family study for hepatitis B was carried out in 8 cases and 7 of them were positive. Only in one case vertical transmission was demonstrated; this patient remained HBeAg positive. In 7 patients, hepatic biopsy was performed: 3 had a chronic active hepatitis, 3 a persistent chronic hepatitis and one a residual acute hepatitis. CONCLUSIONS: Membranous nephropathy is a rare pediatric disease in our area and most of the cases are related to hepatitis B (HB). The outcome was excellent with and without treatment but all of them remained HBsAg positive.

Child↗
PubMed2000

Ion-mediated resistance to osmotic changes of ram spermatozoa: the role of amiloride and ouabain.

The aim of this study was to evaluate whether the Na+/K+ and Na+/H+ exchange can maintain the function of fresh ram spermatozoa. We analyzed the quality parameters of spermatozoa from fresh ram ejaculates incubated in iso- (about 300 mOsm), hypo- (about 100 mOsm) and hyperosmotic (about 900 mOsm) media in the presence of ouabain a specific inhibitor of the Na+/K+ ATP-ase or amiloride, a specific inhibitor of the Na+/H+ antiporter. Ouabain increased the percentage of morphologically altered acrosomes in isoosmotic media (from about 10% to 15% in control to about 30% with 10(-4) M ouabain) and decreased the percentage of total motility (from about 80% in control to about 50% to 55% with 10(-4) M ouabain). Ouabain decreased the mean linearity component of motility and decreased the frequency of head displacement. The addition of ouabain increased the percentage of altered acrosomes in the hypo- and hyperosmotic media, although it did not modify viability in either media. Ouabain also increased the percentage of swollen tails in the hypoosmotic medium at higher concentrations of the inhibitor. Amiloride increased the percentage of altered acrosomes in all media although its effect was less intense than that of ouabain. In isoosmotic media, total motility was decreased from about 80% in control to about 65% with 10(-4) M amiloride. Motile spermatozoa incubated with amiloride showed a clear decrease of mean velocity and mean linearity and increased frequency of head displacement. In the hyperosmotic medium, adding amiloride decreased the percentage of viability and altered tails at concentrations as low as 10(-6) to 10(-5) M. Our results indicate that the active mechanisms which control Na+ transport play a significant role in the maintenance of function in ram spermatozoa subjected to different osmotic environments. These mechanisms may be important in maintaining ram sperm function both "in vivo" and "in vitro".

Acrosome↗
PubMed2000

Human caliciviruses are a significant pathogen of acute sporadic diarrhea in children of Santiago, Chile.

Human caliciviruses (HuCVs) are increasingly recognized as common pathogens that cause acute sporadic diarrhea in children; however, regional antigenic and genetic diversity complicate detection techniques. Stool samples from children seeking medical attention in 2 outpatient clinics, a large emergency department, and 2 hospital wards were evaluated for HuCVs by reverse transcription-polymerase chain reaction, using primers based on a conserved sequence of the polymerase region of a previously sequenced Chilean strain. HuCVs were detected in 53 (8%) of 684 children 1 month to 5 years of age (mean, 13 months). Detection occurred year-round without a clear seasonal peak, and detection frequency declined from 16% in 1997 to 2% in 1999. The decline may have been due to a change in virus genotype. HuCVs are a significant pathogen of acute sporadic diarrhea in Chilean children, and continuous characterization of genetic diversity will be crucial for appropriate detection.

Acute Disease↗
PubMed2000

Regulation of monovalent ion homeostasis and pH by the Ser-Thr protein phosphatase SIT4 in Saccharomyces cerevisiae.

A gene, SIT4, was identified as corresponding to a serine/threonine protein phosphatase and when overexpressed confers lithium tolerance in galactose medium to the budding yeast Saccharomyces cerevisiae. This gene has been previously identified as a regulator of the cell cycle and involved in nitrogen sensing. It is shown that the transcription levels of SIT4 are induced by low concentrations of Li(+) in a time-dependent manner. Na(+) and K(+) at high concentrations, but not sorbitol, also induce transcription. As a response to Na(+) or Li(+) stress, yeast cells lower the intracellular K(+) content. This effect is enhanced in cells overexpressing SIT4, which also increase (86)Rb efflux after the addition of Na(+) or Li(+) to the extracellular medium. Another feature of SIT4-overexpressing cells is that they maintain a more alkaline pH of 6.64 compared with 6.17 in the wild type cells. It has been proposed that the main pathway of salt tolerance in yeast is mediated by a P-type ATPase, encoded by PMR2A/ENA1. However, our results show that in a sit4 strain, expression of ENA1 is still induced by monovalent cations, and overexpression of SIT4 does not alter the amount of ENA1 transcript. These results show that SIT4 acts in a parallel pathway not involving induction of transcription of ENA1 and suggest a novel function for SIT4 in response to salt stress.

Adenosine Triphosphatases↗
PubMed2000

Effects of Equex, one- or two-step dilution, and two freezing and thawing rates on post-thaw survival of dog spermatozoa.

The objectives of the present study were to evaluate the effects of adding Equex to a TRIS-extender, diluting the semen in 1 or 2 steps, freezing according to 2 methods, thawing at 2 rates, and the interactions between these treatments, on the post-thaw survival of dog spermatozoa at 38 degrees C. Ten ejaculates were obtained from 8 dogs. Each ejaculate was centrifuged, and the seminal plasma was discarded. Each sperm pellet was diluted with 2 mL of a TRIS-glucose-egg yolk extender containing 3% glycerol (Extender 1 [Ext-1]). Ejaculates were then pooled (9 x 10(9) spermatozoa), and Ext-1 was added to obtain 200 x 10(6) spermatozoa/mL. The semen pool was carefully mixed and divided into aliquots, and processed according to a 2 x 2 x 2 x 2 factorial design to evaluate the effects of 1) adding the same volume of a second TRIS-glucose-egg yolk extender with 7% glycerol that contained (Ext-2-E) or didn't contain (Ext-2) 1% of Equex STM Paste (final concentration of spermatozoa 100 x 10(6) spermatozoa/mL, glycerol 5%, Equex 0% [Ext-2] or 0.5% [Ext-2-E]); 2) diluting the semen in 1 step (adding Ext-2 or Ext-2-E before equilibration) or in 2 steps (adding Ext-2 or Ext-2-E after equilibration, just before the freezing operation); 3) freezing the straws horizontally in a styrofoam box 4 cm above liquid nitrogen (LN2) or by lowering them vertically into a LN2 tank in 3 steps; and 4) thawing at 70 degrees C for 8 sec or at 37 degrees C for 15 sec. A total of 16 treatment combinations were evaluated. Sperm motility was evaluated after thawing and at 1-h intervals during 7 h of incubation at 38 degrees C by subjective examination and by using a CASA-system. Plasma membrane integrity and acrosomal status were evaluated simultaneously at 1, 3 and 6 h post-thaw using a triple fluorescent staining procedure and flow cytometry. The best post-thaw survival and thermoresistance of spermatozoa was obtained when Equex was present in the extender (P<0.0001); the semen dilution was performed in 2 steps instead of 1 (P<0.0001); the freezing was carried out using the box instead of the tank (P<0.05); and the straws were thawed at 70 degrees C for 8 sec instead of at 37 degrees C for 15 sec (P<0.0001).

Acrosome↗