Colorimetric microwell plate reverse-hybridization assay for Mycobacterium tuberculosis detection

Direct smear examination using Ziehl-Neelsen staining for pulmonary tuberculosis (PTB) diagnosis is inexpensive and easy to use, but has the major limitation of low sensitivity. Rapid molecular methods are becoming more widely available in centralized laboratories, but they depend on timely reporting of results and strict quality assurance obtainable only from costly commercial kits available in high burden nations. This study describes a pre-commercial colorimetric method, Detect-TB, for detecting Mycobacterium tuberculosis DNA in which an oligonucleotide probe is fixed onto wells of microwell plates and hybridized with biotinylated polymerase chain reaction amplification products derived from clinical samples. The probe is capable of hybridising with the IS6110 insertion element and was used to specifically recognise the M. tuberculosis complex. When combined with an improved silica-based DNA extraction method, the sensitivity of the test was 50 colony-forming units of the M. tuberculosis reference strain H37Rv. The results that were in agreement with reference detection methods were observed in 95.2% (453/476) of samples included in the analysis. Sensitivity and specificity for 301 induced sputum samples and 175 spontaneous sputum samples were 85% and 98%, and 94% and 100%, respectively. This colorimetric method showed similar specificity to that described for commercially available kits and may provide an important contribution for PTB diagnosis

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

Recovery of spermatogenesis after microsurgical subinguinal varicocele repair in azoospermic men based on testicular histology

OBJECTIVE: Analyze whether testicular histologic patterns from a group of azoospermic men with varicocele is predictive of treatment outcome after subinguinal microsurgical varicocele repair. MATERIALS AND METHODS: Seventeen azoospermic men underwent bilateral open single testis biopsy and microsurgical subinguinal repair of clinical varicoceles. RESULTS: Histopathology of testicular biopsies revealed hypospermatogenesis (HYPO) in 6 men, maturation arrest (MA) in 5, and Sertoli cell-only (SCO) in 6. Overall, presence of spermatozoa in the ejaculates was achieved in 47% (8/17) of men after varicocele repair, but only 35% (6/17) of them had motile sperm in their ejaculates. Only men with testicular histology revealing HYPO (5/6) or maturation arrest (3/5) had improvement after surgery. Median (25% - 75% percentile) postoperative motile sperm count for both groups were 0.9 X 106/mL (0.1-1.8 X 106/mL) and 0.7 X 106/mL (0.1-1.1), respectively (p = 0.87). The mean time for appearance of spermatozoa in the ejaculates was 5 months (3 to 9 months). One (HYPO) of 8 (12.5%) men who improved after surgery contributed to an unassisted pregnancy. Postoperative testicular biopsies obtained from patients who had no improvement after surgery revealed that testicular histology diagnosis remained unchanged. Successful testicular sperm retrieval for intracytoplasmic sperm injection (ICSI) was achieved in 4 of 9 (44.4%) individuals who did not improve after surgery, including 1 man with testicular histology exhibiting SCO. CONCLUSION: Microsurgical varicocele repair in nonobstructive azoospermic men with clinical varicoceles can result in sperm appearance in the ejaculate when hypospermatogenesis or maturation arrest is found on testicular histology diagnosis