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Biomedical subjects

S C Esteves

Publications and source records attributed to S C Esteves.

12 recordsLinked to original sources
PubMed2000

Improvement in motion characteristics and acrosome status in cryopreserved human spermatozoa by swim-up processing before freezing.

The purpose of this study was to examine if selecting a sperm population with improved motion characteristics before freezing reduces the deleterious effects of cryopreservation. Semen specimens from 15 normal donors were divided into two equal aliquots. The first aliquot received no treatment (control), and the second was processed by swim-up from a washed sperm preparation to select a sperm population with better motility and motion characteristics (swim-up). Both aliquots were cryopreserved by the liquid nitrogen vapour method. Percentage motility and motion characteristics were evaluated by computer-assisted semen analysis. Acrosome integrity as well as spontaneous and calcium ionophore-induced acrosome reactions before freezing and after thawing were assessed by fluorescein isothiocyanate conjugated peanut agglutinin combined with a supra vital dye (Hoechst-33258). Swim-up processing enabled selection of a sperm population with better motion characteristics, percentage motility and viability before freezing (P < 0.001), but with no difference in percentage of acrosome-intact spermatozoa (P = 0.63). After thawing, the swim-up specimens exhibited faster velocity and progression than untreated specimens (P < 0.001). They also had higher percentages of spermatozoa with intact acrosomes and spermatozoa able to undergo acrosome reaction in response to calcium ionophore (P < 0.05). Selecting a highly motile sperm population before freezing enhances overall post-thaw spermatozoa quality.

Acrosome Reaction↗
PubMed1998

Transurethral resection of partially obstructed ejaculatory ducts: seminal parameters and pregnancy outcomes according to the etiology of obstruction.

PURPOSE: We determine how transurethral resection of the ejaculatory ducts performed for infertility affects seminal parameters and pregnancy outcomes in patients with partial ejaculatory duct obstruction due to a congenital or acquired etiological factor. MATERIALS AND METHODS: Based on history and physical examination, hormonal profiles, semen analyses, transrectal ultrasonography and vasography findings partial ejaculatory duct obstruction was diagnosed in 14 men a mean of 30 years old who presented for infertility evaluation. Patients were grouped according to congenital or acquired cause of obstruction. Transurethral resection of the ejaculatory ducts was performed using the standard resectoscope loop technique. Clinical outcome was assessed by postoperative analyses of seminal parameters and pregnancy reports. RESULTS: Transurethral resection of the ejaculatory ducts significantly improved semen quality (ejaculate volume and percentage of sperm motility) in all patients in the congenital group, while all but 1 (83%) had an improved sperm count. Pregnancy was achieved via sexual intercourse by 66% of the patients an average of 5.7 months postoperatively. Of the acquired etiological factor group 37.5% had improved semen quality after transurethral resection of ejaculatory duct and 12.5% achieved pregnancy via sexual intercourse. Postoperative complications occurred at a similar rate in each group (33%). However, complications in the congenital etiology group were minor, while 25% of the men in the acquired group had significant impairment of seminal parameters after transurethral resection of the ejaculatory ducts. CONCLUSIONS: Semen quality improvement and pregnancy outcome after transurethral resection of the ejaculatory ducts for partial ejaculatory duct obstruction differ significantly according to the main etiological cause of obstruction. An equivocal diagnosis of partial obstruction and technical problems during transurethral resection of the ejaculatory ducts may contribute to failure. However, in some cases the reason for failure remains unclear.

Adult↗
PubMed1998

Cryopreservation of human spermatozoa with pentoxifylline improves the post-thaw agonist-induced acrosome reaction rate.

Cryopreservation causes extensive damage to spermatozoa, thereby impairing their fertilizing ability. The purpose of this study was to determine if the direct addition of pentoxifylline to the seminal plasma before cryopreservation improved sperm motility and acrosome reaction. Semen specimens from 15 healthy volunteers were divided into two aliquots. One aliquot was treated by adding 5 mM pentoxifylline directly to the seminal plasma (treatment group) and the other aliquot received no treatment (control group). Both aliquots were then cryopreserved by using the liquid nitrogen freezing method. The percentage of motile spermatozoa and various motion characteristics were then evaluated by performing computer-assisted semen analysis. The sperm viability was determined with a supra-vital dye, Hoechst-33258, and the acrosome reaction (spontaneous and calcium ionophore-induced) was monitored using fluorescein isothiocyanate-conjugated peanut lectin (FITC-PNA) binding assays. Pentoxifylline treatment significantly increased the sperm motility, the amplitude of lateral head displacement, the hyperactivation status, and the frequency of spontaneous acrosome reactions before freezing (P < 0.05). After post-thaw, no difference in motion characteristics (except percentage motility) between treated and control groups were observed. Acrosome loss due to the freeze-thaw process was less in the pentoxifylline-treated group (P = 0.0003). In addition, the percentage of cryopreserved acrosome-intact spermatozoa that underwent further acrosome reactions in response to calcium-ionophore challenge was significantly higher in the treated group (P = 0.03). Pentoxifylline treatment before freezing improved the acrosome reaction to ionophore challenge in cryopreserved spermatozoa. Treatment with pentoxifylline appears to minimize sperm damage during the freeze-thaw process and may improve fertilization rates with assisted reproductive procedures such as intrauterine insemination or in-vitro fertilization.

Acrosome Reaction↗
PubMed1997

Ureteroscopic stone removal in the distal ureter. Why change?

PURPOSE: We compared our experience with ureteroscopic stone basket manipulation under fluoroscopic guidance to ultrasound ureterolithotripsy for distal ureteral stone removal. MATERIALS AND METHODS: Retrospectively, we analyzed the medical records of 981 patients with ureteral calculi between January 1994 and December 1995, of whom 483 (49%) were treated for stones in the lower ureter and constituted our study group. The decision of when to perform lithotripsy (group 2) versus a basket procedure (group 1) was based on a prospective nonrandomized study and both groups were compared historically. All 322 patients in group 1 (mean age 49 years, range 14 to 86) primarily underwent ureteroscopic stone basket manipulation using the 4-wire Segura* basket. If the calculus could not be removed with the basket and another procedure was necessary, the case was considered a failure. The 161 patients in group 2 (mean age 37 years, range 14 to 74) underwent initially ultrasound ureterolithotripsy for stone fragmentation followed or not by removal of the fragments with the basket. Stone size did not differ significantly between groups 1 (mean 0.9 cm., range 0.6 to 1.7) and 2 (mean 0.8 cm., range 0.7 to 2.0). Ureteroscopy was performed in both groups with epidural anesthesia and on an outpatient basis in the majority of cases. RESULTS: The stone-free rate after 1 procedure was 98.1 and 95.6% in group 1 and 2, respectively. For group 2 versus group 1 the operative time was longer (mean 50, range 25 to 90 versus mean 19 minutes, range 11 to 40, respectively, p < 0.001), the complication rate was greater (16.1 versus 4.3%, respectively, p < 0.001) and average hospital stay was longer (2.1 versus 0.15 day, respectively, p < 0.001). CONCLUSIONS: Ureteroscopic stone treatment with basket manipulation under fluoroscopic guidance or ultrasound ureterolithotripsy provided a high stone-free rate. However, stone removal with the basket manipulation technique should be considered the first choice for treatment of small distal ureteral calculi based on the minimal morbidity, and short operative and recovery times.

Adolescent↗
PubMed1996

Antegrade endopyelotomy for pelvi-ureteric junction obstruction in children.

OBJECTIVE: To compare the results of repairing pelvi-ureteric junction (PUJ) obstruction by percutaneous endopyelotomy in children with a similar series carried out in adults. PATIENTS AND METHODS: Nine children with primary (six) or secondary (three) PUJ obstruction were treated using a one-stage cold-knife percutaneous endopyelotomy. The success and morbidity rates were compared with a series of 61 adults with primary (46) or secondary (15) PUJ obstruction treated similarly. RESULTS: In children, endopyelotomy was successful in five of six with primary and two of three with secondary PUJ obstruction, with a mean follow-up of 30 months (range 18-56). In the adults, endopyelotomy was successful in 38 of 46 (83%) with primary and 12 of 15 with secondary PUJ obstruction, an overall success rate of 82%, with a mean follow-up of 42 months (range 9-86). There was no statistical difference in the success rates with primary and secondary endopyelotomy between adults and children (P = 0.58). Failures were associated with high-grade hydronephrosis, a stenotic segment > 1.5 cm long and technical problems. Morbidity occurred in one of nine children and 3.2% of the adults. CONCLUSION: This early experience suggests that percutaneous endopyelotomy can be performed safely and successfully in children with primary PUJ obstruction. However, in secondary stenosis, the results were less than optimal. Larger series should be analysed to form definitive conclusions on the role of endopyelotomy for the treatment of PUJ obstruction in children, given the high rate of success of open pyeloplasty and its minimal morbidity.

Adolescent↗
PubMed1996

Suitability of the hypo-osmotic swelling test for assessing the viability of cryopreserved sperm.

OBJECTIVE: To determine whether the hypo-osmotic swelling test can assess viability of frozen spermatozoa. DESIGN: Fresh semen specimens were divided into two aliquots: one was not processed and the other was processed by swim-up. Both aliquots were then cryopreserved by the liquid nitrogen vapor method. SETTING: Andrology laboratory at a tertiary care facility. PATIENT(S): Eleven volunteers with proven fertility. INTERVENTION(S): The hypo-osmotic swelling test and the sperm viability assessment by Hoechst 33258 (Sigma Chemical Co., St. Louis, MO) and eosin-nigrosin strains were performed in each aliquot. MAIN OUTCOME MEASURE(S): The results of hypo-osmotic swelling test as indicated by swelling of sperm tails were compared with the viability results obtained by Hoechst 33258 stain before freezing and by Hoechst-33258 and eosin-nigrosin stains after freezing. RESULT(S): The hypo-osmotic swelling test and Hoechst 33258 viability results were correlated highly in unprocessed and processed fresh specimens (r = 0.95). After cryopreservation, there was no correlation between hypo-osmotic swelling test and Hoechst 33258 or between hypo-osmotic swelling test and eosin-nigrosin. Prefreeze sperm processing did not influence the post-thaw results. Viability assessed by Hoechst 33258 and eosin-nigrosin was well correlated (r = 0.72). CONCLUSION(S): The hypo-osmotic swelling test can accurately evaluate viability in fresh human spermatozoa but not in cryopreserved ones. Thus, this test cannot be used to select viable cells in cryopreserved samples for assisted reproductive procedures, such as intracytoplasmic sperm injection.

Aniline Compounds↗
PubMed1991

Comparative study of the fertility potential of men with only one testis.

The fertility potential of 54 men aged between 19 and 42 years, who had undergone unilateral orchidectomy was evaluated. In all cases the remaining testis was of normal volume and consistency. The patients were divided into four groups according to the cause of the orchidectomy: group I--cryptorchism (n = 19), group II--testicular torsion (n = 14), group III--testicular cancer (n = 12) and group IV--accidental (n = 9). The time between orchidectomy and seminal analysis varied from 6 months to 30 years (median 5 years). All semen samples were examined at the same laboratory, and no differences in sperm concentration were found among the groups. 53% in group I, 57% in group II, 50% in group III, and 56% in group IV had sperm counts of less than 20 million/ml. Our results suggest that unilateral orchidectomy leads to a considerable decrease in fertility potential, whatever the reason for it.

Adult↗
PubMedDate not supplied

Effect of swim-up sperm washing and subsequent capacitation on acrosome status and functional membrane integrity of normal sperm.

OBJECTIVE: Sperm preparation techniques select sperm population with improved sperm motion characteristics. We sought to determine whether the swim-up technique selects spermatozoa with the ability to undergo hypoosmotic swelling, and how swim-up and subsequent capacitation affect the acrosome reaction rate. METHODS: Semen specimens from 15 normal donors were divided into unprocessed, swim-up, and capacitated groups, and sperm motion characteristics, ability to undergo hypoosmotic swelling, and acrosome reaction rate were measured. RESULTS: Sperm motility, viability, and all motion characteristics (except linearity) were significantly increased in both swim-up and capacitated specimens. The ability to respond to hypoosmotic swelling was significantly higher in the spermatozoa isolated by swim-up. The percentage of acrosome-reacted spermatozoa remained unchanged in both unprocessed and swim-up groups, but was significantly higher in the capacitated group. CONCLUSIONS: Swim-up isolates sperm with greater ability to undergo hypoosmotic swelling, but does not change the acrosome reaction rate. In vitro capacitation of spermatozoa selected by swim-up enhances the acrosome reaction rate.

Acrosome↗
PubMedDate not supplied

[High dose rate brachytherapy].

The high dose rate brachytherapy uses a single source os 192Ir with 10Ci of nominal activity in a remote afterloading machine. This technique allows an outpatient treatment, without the inconveniences of the conventional low dose rate brachytherapy such as use of general anesthesia, rhachianesthesia, prolonged immobilization, and personal exposition to radiation. The radiotherapy department is now studying 5 basic treatment schemes concerning carcinomas of the uterine cervix, endometrium, lung, esophagus and central nervous system tumors. With the Micro Selectron HDR, 257 treatment sessions were done in 90 patients. Mostly were treated with weekly fractions, receiving a total of three to four treatments each. No complications were observed neither during nor after the procedure. Doses, fraction and ideal associations still have to be studied, so that a higher therapeutic ratio can be reached.

Brachytherapy↗
PubMedDate not supplied

Influence of subacute starvation on cardiac response to isoproterenol in rats.

Several studies have reported that the heart is severely affected by chronic malnutrition. However, the influence of these alterations on cardiac function remains unclear. The aim of this study was to evaluate the effects of subacute starvation on the heart chronotropic response to a beta-adrenergic agonist (isoproterenol). Twelve rats were fed rat chow ad libitum or a 50%-restricted diet for 17 days. The rats were killed, the right atrium was isolated and incubated, and in vitro spontaneous cardiac contractions and frequency were registered. Cumulative doses of isoproterenol were added to the solution until maximal cardiac frequency was achieved. A deficit of 25% in the weight gain was observed in study rats compared with controls (92.6 +/- 10.2 vs. 113.8 +/- 19.2 g, p less than 0.05). Mean daily food intake was 4.8 +/- 0.1 and 9.8 +/- 0.5 g/day for semistarved and control rats, respectively. The in vitro cardiac frequency of the semistarved rats was similar to that of controls (290 +/- 15 and 305 +/- 23 beats/min, respectively, NS). However, when isoproterenol was added to the solution, maximal cardiac frequency of the semistarved rats (435 +/- 51 beats/min) was lower than that of control rats (508 +/- 34 beats/min, p less than 0.005). These findings suggest that subacute starvation may alter the cardiac response to beta-adrenergic agonists.

Animals↗
PubMedDate not supplied

Effect of in vitro incubation on spontaneous acrosome reaction in fresh and cryopreserved human spermatozoa.

OBJECTIVES: Capacitation and acrosome reaction are prerequisites for fertilization. However, in vitro capacitation is not necessary for an agonist-induced acrosome reaction. We studied whether in vitro capacitation is important in spontaneous acrosome reaction and analyzed how capacitation before cryopreservation influences the acrosomal status of thawed spermatozoa. METHODS: Semen specimens from normal donors (n = 15) were processed by the swim-up technique and divided into two aliquots. One aliquot was capacitated (capacitation induced) for three hours by incubation in a modified-BWW medium with 3% HSA at 37 degrees C under 5% carbon dioxide. The other aliquot did not receive any treatment. Both aliquots were analyzed by CASA to assess the capacitation status of the spermatozoa and then cryopreserved. Spontaneous acrosome reaction was assessed by FITC-PNA lectin before and after cryopreservation. Sperm viability was measured using Hoechst-33258 stain. RESULTS: Before freezing, the frequency of spontaneous acrosome reaction was higher in the capacitation-induced sperm preparation (median, 20.5% [interquartile range, 17.2-37.8]) than in swim-up-induced specimens (median, 10.6% [range, 4.8-23.2]; P <.001). The percentage of viable cells showing acrosome reaction increased after cryopreservation in both swim-up-induced specimens (median, 241.4% [interquartile range, 37.1-678.6]; P <.001) and capacitation-induced specimens (median, 48.2% [range, 6.1-63.3]; P = 0.002). Although this increase was higher in the swim-up-induced specimens (P = 0.002), frequency of postthaw spontaneous acrosome reaction was similar in both groups (P = 0.18). CONCLUSIONS: We conclude that sperm capacitation significantly optimizes the acrosome reaction. However, a small proportion of normal spermatozoa do not require capacitation to undergo spontaneous acrosome reaction in vitro. After cryopreservation, the percentage of spermatozoa that had intact acrosomes was similar in both groups, despite the fact that one aliquot underwent prefreeze capacitation. These findings suggest that the acrosome reaction may involve complex mechanism(s) rather than a physiological change induced by capacitation.

Acrosome Reaction↗