Feasibility of refreezing human spermatozoa through the technique of liquid nitrogen vapor

OBJECTIVE: To assess the feasibility of refreezing human semen using the technique of liquid nitrogen vapor with static phases. MATERIALS AND METHODS: Twenty samples from 16 subjects who required disposal of their cryopreserved semen were thawed, corresponding to 6 cancer patients and 10 participants in the assisted reproduction (AR) program. Samples were refrozen using the technique of liquid nitrogen vapor with static phases, identical to the one used for the initial freezing, and thawed again after 72 hours. We assessed the concentration of motile spermatozoa, total and progressive percent motility and spermatic vitality, according to criteria of the World Health Organization (WHO), as well as spermatic morphology according to the strict Kruger criterion, after the first and after the second thawing. RESULTS: We observed a significant decrease in all the parameters evaluated between the first and the second thawing. Median values for the concentration of motile spermatozoa decreased from 2.0x10(6)/mL to 0.1x10(6)/mL (p < 0.01); total percent motility from 42% to 22.5% (p < 0.01); progressive percent motility from 34% to 9.5% (p < 0.01); vitality from 45% to 20% (p < 0.01); and morphology from 5% to 5% (p = 0.03). There was no significant difference in the spermatic parameters between the cancer and assisted reproduction groups, both after the first and after the second thawing. We observed that in 100% of cases there was retrieval of motile spermatozoa after the second thawing. CONCLUSIONS: Refreezing of human semen by the technique of liquid nitrogen vapor allows the retrieval of viable spermatozoa after thawing

Resistance of human spermatozoa to cryoinjury in repeated cycles of thaw-refreezing

Objective: To study the resistance of human spermatozoa to cryoinjury in repeated cycles of thaw-refreezing by using the fast liquid nitrogen vapor method. Material and Methods: Semen specimens were obtained from sixteen normal and oligozoospermic individuals who required disposal at the sperm bank. Five of them had testicular cancer. Specimens were thawed and an aliquot was removed for analysis. The remaining specimens were refrozen without removing the cryomedia. Repeated freeze-thaw cycles were performed until no motile sperm were observed. Sperm motility, number of motile spermatozoa and viability were determined after thawing. Resistance to cryoinjury was compared between groups and also after each refreezing cycle within groups. Results: Motile spermatozoa were recovered after five and two refreeze-thawing cycles in normozoospermic and oligozoospermic specimens, respectively. There were no significant differences in the recovery of motile spermatozoa between thaws within each group of normal and oligozoospermic specimens, but percentage motility and total number of motile spermatozoa were significantly lower in the oligozoospermic one. Specimens from men with cancer were exposed to six refreeze-thawing cycles. Although recovery of motile spermatozoa was significantly impaired after each thawing, there were no significant differences in the recovery of motile sperm between thaws in cancer and non-cancer groups. Conclusions: Human spermatozoa resist repeated cryopreservation using the fast liquid nitrogen vapor method. Normozoospermic specimens withstand refreezing for an average two cycles longer than oligozoospermic ones. Specimens from cancer patients seem to resist repeated cryoinjury similarly to non-cancer counterparts. Resistance to repeated cryoinjury was related to the initial semen quality

O emprego do cateter duplo J diminui as complicações na ureterolitotomia retroperitoneoscópica

OBJETIVO: Avaliar os resultados da ureterolitotomia retroperitoneoscópica no tratamento do cálculo ureteral e a necessidade do cateter duplo J para reduzir complicações relacionadas ao procedimento. MÉTODOS: Estudo retrospectivo comparativo de 47 pacientes operados pela técnica de ureterolitotomia retroperitoneoscópica, dos quais 31 foram selecionados e divididos em dois grupos: Grupo 1, cujos pacientes não receberam cateter duplo J, e Grupo 2, que foram submetidos ao implante de cateter duplo J transoperatório. Foram coletados dados de urografia excretora pré e pós-operatória, tempo cirúrgico, analgesia pós-operatória, tempo de internação e retirada do dreno. RESULTADOS: Os grupos foram semelhantes quando comparados na idade e sexo, grau de dilatação do trato urinário, posição e tamanho médio do cálculo (Grupo 1= 15,5 ± 6,6mm; Grupo 2= 16,3 ± 6,1mm). O tempo operatório também não teve diferença significativa (Grupo 1= 130 ± 40,3min; Grupo 2= 136,3 ± 49,3min). O Grupo 1 apresentou seis pacientes (37,5 %) com complicações precoces (quatro casos de fístula urinária) e tardias (um caso de estenose de ureter, um caso de exclusão funcional do rim operado), enquanto o Grupo 2 não teve complicações, sendo esta diferença estatisticamente significativa (p=0,011). CONCLUSÃO: O emprego do cateter duplo J foi associado a um número significativamente menor de complicações na ureterolitotomia retroperitoneoscópica. Tempo cirúrgico, analgesia pós-operatória e tempo de internação foram semelhantes entre os grupos com e sem cateter