[Liver transplantation during pregnancy in a patient with acute liver failure]

Liver transplantation is the best therapeutic approach in patients with acute liver failure. This clinical presentation during pregnancy is an unusual and dramatic event. We report the case of a 18 year-old woman with cryptogenic acute liver failure who underwent successful orthotopic liver transplantation at 20 weeks of pregnancy. Both outcomes were analyzed. Fetal death was observed within 48 hours after liver transplant. After six months of follow-up, the patient is doing well. This case illustrates the challenge of treating acute liver failure during pregnancy and demonstrates that liver transplantation is a feasible therapeutic option for treatment of patient with this condition.

Swim-up procedure selects spermatozoa with longer telomere length

Telomere length and sperm DNA fragmentation were determined in sperm samples from 27 patients, using a quantitative PCR (Q-PCR) assay and the Sperm Chromatin Dispersion (SCD) test, respectively. Comparisons of the samples before and after swim-up processing demonstrated that this procedure selects a sperm population with longer average telomere size and lower frequency of sperm cells with fragmented DNA.

Differing patterns of peripheral blood leukocyte telomere length in rheumatologic diseases

Telomeres progressively shorten with repeated somatic tissue cell division, their length being an indicator of cellular ageing. Telomeric dysfunction may be implicated in a variety of diseases. We measured mean telomere length in peripheral blood leukocytes (PBL) from patients with various rheumatologic diseases. Mean PBL telomere length was measured using real-time quantitative polymerase chain reaction (Q-PCR) assay in a control population (n=130; age range: 3-94 years) and in subjects diagnosed with rheumatoid arthritis (RA; n=86; age range: 31-82 years), psoriatic arthritis (PA; n=56; age range: 26-79 years) and ankylosing spondylitis (AS; n=59; age range: 21-75 years). These diseases are associated with chronic systemic inflammatory activity. Telomere length was also quantified in subjects with osteoarthritis (OA; n=34; age range: 43-82 years) and osteoporosis (OP; n=35; age range: 59-95 years), diseases without a chronic systemic inflammatory component. Telomere length in OA showed no differences from age-matched controls (p=0.234), but was significantly shorter in OP (p=0.001). Telomere length was significantly longer than controls in RA (p=0.015), PA (p<0.001) and AS (p<0.001). Different patterns in telomere length from PBL are evidenced in rheumatologic pathologies, possibly dependent on the presence or absence of chronic systemic inflammation.

Simultaneous determination in situ of DNA fragmentation and 8-oxoguanine in human sperm

Deoxyribonucleic acid fragmentation and oxidative DNA damage were simultaneously determined in the same sperm cell, incubating with an 8-oxoguanine DNA probe on human spermatozoa processed by the sperm chromatin dispersion test. The assay was validated by incubation with agents that induce DNA fragmentation with or without oxidative base damage. In all samples examined, increased levels of 8-oxoguanine were present only in those spermatozoa with fragmented DNA, suggesting a link between both DNA damage types.

The European contribution to "Sugarbaker's protocol" for the treatment of colorectal peritoneal carcinomatosis

INTRODUCTION

In 1981, Dr. PH Sugarbaker, challenging oncological orthodoxy, considered carcinomatosis to be a locoregional stage of the disease that was still susceptible to treatment with curative intent. To this end he developed a new therapeutic alternative based on the combined treatment. The macroscopic disease treated by maximum radical oncological cytoreductive surgery (through the peritonectomies described by him), followed by treatment of the residual microscopic disease with the direct intra-abdominal application of intraoperative chemotherapy with locoregional intensification, modulated by hyperthermia and early normothermic postoperative intra-abdominal chemotherapy. Using this new therapeutic regimen, known as "Sugarbaker s Protocol", his group has reported 45% survival rates in carcinomatosis of colorectal origin at 5 years, and, in selected groups of patients, 50% survival rates at 5 years. The scientific community, however, has criticized these results considering that: it is a personal experience, with a not homogenous treatment protocol with developmental modifications over time, that it is a retrospective non-randomized study, and finally that the cytostatics used in his protocol are obsolete. Various European groups have replied to these main criticisms confirming the good results that this new therapeutic alternative offers for patients with carcinomatosis of colorectal origin. The purpose of this article is to present these contributions.

MATERIAL AND METHODS

All the articles published in the English language by European groups in the world s medical literature have been reviewed using the Pubmed-MEDLINE database to identify the relevant articles related to the treatment of carcinomatosis of colorectal origin using cytoreduction and intraperitoneal chemotherapy from January 1980 to January 2008.

RESULTS

The European contribution during these 25 years in favour of the "Sugarbaker s Protocol" has consisted fundamentally in: a) one multicenter retrospective study; b) two randomized prospective phase III studies; and c) the use of oxaliplatin and irinotecan as new cytostatic agents in the protocols for intraperitoneal chemotherapy. At the same time, two new transcendental European contributions have been made in which the possibility has been considered of combined simultaneous treatment for patients with hepatic metastases and carcinomatosis, and the introduction, as a selection factor, of patients responsive to intravenous induction chemotherapy within the regimen of sandwich treatment (with systemic neoadjuvant and adjuvant chemotherapy) complementary to intraperitoneal chemotherapy.

CONCLUSIONS

The results obtained by European groups using "Sugarbaker s protocol" and "Elias protocol" with oxaliplatin compel us to request that these treatments be considered by all professionals involved in the treatment of patients with colorectal carcinomatosis as the best treatment currently available for this condition. Furthermore a randomized, prospective, multicenter study should be carried out to clarify its value and the degree of scientific evidence. A validation of this treatment will change, in the future, the dogmatic consideration of carcinomatosis as an incurable disease stage.

Rapid assessment of the effect of ciprofloxacin on chromosomal DNA from Escherichia coli using an in situ DNA fragmentation assay

Background

Fluoroquinolones are extensively used antibiotics that induce DNA double-strand breaks (DSBs) by trapping DNA gyrase and topoisomerase IV on DNA. This effect is usually evaluated using biochemical or molecular procedures, but these are not effective at the single-cell level. We assessed ciprofloxacin (CIP)-induced chromosomal DNA breakage in single-cell Escherichia coli by direct visualization of the DNA fragments that diffused from the nucleoid obtained after bacterial lysis in an agarose microgel on a slide.

Results

Exposing the E. coli strain TG1 to CIP starting at a minimum inhibitory concentration (MIC) of 0.012 μg/ml and at increasing doses for 40 min increased the DNA fragmentation progressively. DNA damage started to be detectable at the MIC dose. At a dose of 1 μg/ml of CIP, DNA damage was visualized clearly immediately after processing, and the DNA fragmentation increased progressively with the antibiotic incubation time. The level of DNA damage was much higher when the bacteria were taken from liquid LB broth than from solid LB agar. CIP treatment produced a progressively slower rate of DNA damage in bacteria in the stationary phase than in the exponentially growing phase. Removing the antibiotic after the 40 min incubation resulted in progressive DSB repair activity with time. The magnitude of DNA repair was inversely related to CIP dose and was noticeable after incubation with CIP at 0.1 μg/ml but scarce after 10 μg/ml. The repair activity was not strictly related to viability. Four E. coli strains with identified mechanisms of reduced sensitivity to CIP were assessed using this procedure and produced DNA fragmentation levels that were inversely related to MIC dose, except those with very high MIC dose.

Conclusion

This procedure for determining DNA fragmentation is a simple and rapid test for studying and evaluating the effect of quinolones.

Assessing sperm DNA fragmentation in the field: an adaptation of sperm chromatin dispersion technology

The sperm chromatin dispersion (SCD) test is a new technique that allows assessment of sperm DNA fragmentation (SDF) in different species. The application of this technique, like other techniques, is restricted to the laboratory. Our investigation was aimed at exploring the possibilities of extending SCD methodology for use in the field, where electric powered facilities such as freezers, microscopes or heaters are not available. Our results showed that SCD methodology, with minor modifications to the standard protocol, can be performed readily in the field, offering reliable information about SDF. An Light Emitting Diode (LED)-equipped microscope attached to a laptop, a gas heater and a CO(2) spray for cooling are sufficient to assess the quality of sperm DNA. The results obtained after assessing 10 different semen samples under different conditions (30 degrees C in the laboratory and at 17 degrees C and 4 degrees C in the field) showed that except after processing the slides at 4 degrees C, the results of SDF in different animals showed no significant differences. With the modifications suggested here, the SCD technique can be used to assess SDF in the wild. In particular, the DNA quality of spermatozoa obtained from animals post mortem can be assessed in the field.

Sperm DNA fragmentation in infertile men with genitourinary infection by Chlamydia trachomatis and Mycoplasma

OBJECTIVE

To determine the frequency of sperm cells with fragmented DNA in semen samples from men with genitourinary infection by Chlamydia trachomatis and Mycoplasma and the influence of antibiotic therapy, using the sperm chromatin dispersion test with the Halosperm kit.

DESIGN

Prospective study.

SETTING

University-affiliated reproductive medicine center, medical genetics laboratory, and academic biology center.

PATIENT(S)

One hundred forty-three male member of couples attending the andrology infertility center and a group of 50 fertile subjects. The effect of antibiotic treatment was evaluated in 95 male patients.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Classical semen analysis (concentration, motility, morphology, and vitality), sperm DNA fragmentation, and clinical outcome.

RESULT(S)

The mean percentage of sperm cells with fragmented DNA was 35.2% +/- 13.5%, 3.2 times higher than in the control fertile group (10.8% +/- 5.6%). Concentration, morphology, and motility were also significantly affected but to a much lower degree. Sperm vitality was not significantly affected. After 3.8 +/- 2.2 months of antibiotic treatment, the mean frequency of spermatozoa with fragmented DNA decreased from 37.7% +/- 13.6% to 24.2% +/- 11.2%. Sperm concentration and motility were not significantly improved. In a group of 16 couples who attempted pregnancy during antibiotic treatment course, only 12.5% achieved pregnancy. However, in a group of 14 couples who attempted pregnancy after finishing the antibiotic treatment, 85.7% achieved it. The only significant differences found between groups was the rate of sperm DNA fragmentation and morphology.

CONCLUSION(S)

Patients with genitourinary infection by Chlamydia trachomatis and Mycoplasma have increased sperm DNA fragmentation in comparison with fertile controls. This increase is proportionally greater than the influence on classical semen parameters and could result in a decreased fertility potential. Antibiotic therapy appears to be important in providing a remedy for infection-induced high DNA fragmentation levels.

Sperm DNA fragmentation in a random sample of the Spanish boar livestock

A collection of 180 chilled boar semen samples, randomly chosen from stocks currently used for routine characterization of standard seminal quality, were studied for DNA fragmentation status using the sperm chromatin dispersion test and the DNA fragmentation index (DFI: percent of abnormal cell versus normal cells for DNA fragmentation) was determined. Values for sperm motility, acrosome status, coiled tails and abnormal head morphology, including presence and position of cytoplasmic droplets were also obtained. The DFI in the whole sample presented a wide range of variation with values oscillating between practically 0% and 47.95% and do not fit to a normal distribution. The most frequent classes (83.3%) presented a DFI lower than a 5%. Significant correlations between sperm DNA fragmentation and sperm motility, acrosome status, frequency of distal droplets, coiled tails and abnormal head morphology, were not observed. However, the presence of proximal cytoplasmic droplets showed a significant correlation with the level of DNA fragmentation observed in the ejaculated spermatozoa.

[Assessing sperm DNA damage]

Infertility affects almost 20% of couples in reproductive age and the male factor being responsible of 50% of this infertility. Among the classic parameters that determine a good seminal quality such as sperm motility, sperm morphology or the quality of the of acrosomes and/or sperm membranes, the integrity of the DNA molecule is crucial to carry out a successful fertilization. Nevertheless, the study of this parameter has not been straightforward approached. This fact has shunned its incorporation, as a routine technique, within a standard seminogram. The aim of the present review is to summarize and update those technologies that are considered more successful to study sperm DNA fragmentation with special emphasis to: 1) the levels of technological complexity and the possibility of its use in laboratories of andrology, according with the equipment and the resources available, and 2) the effects and possible implications of high level of sperm DNA fragmentation for fecundation, embryo development and fertility.

Triplex configuration in the nick-free DNAs that constitute the chromosomal scaffolds in grasshopper spermatids

After applying proper deoxyribonucleic acid (DNA) probes, fluorescence in situ hybridization (FISH) showed that the 8/9 centromeres-one per chromatid of the male haploid complement (X0) of Pyrgomorpha conica grasshopper-colocalized at the spermatid blunt end, where the spermatozoa flagellum inserts. A bundle of aligned 4',6-diamidino-2-phenylindole-positive chromatid scaffolds, which formed the central spermatid core, was observed after DNA breakage detection followed by FISH. Modular nature of scaffold DNA was occasionally evident. The technique also showed that in the early spermatid, the chromatid scaffolds lacked any DNA nick, whereas abundant breaks accumulated in the surrounding loops. Moreover, immunodetection showed that scaffold DNA participated in the formation of triplex DNA, while this configuration was absent from the loops. During spermatid maturation, triplex DNA disappeared from the scaffold in parallel with loop retraction, while protamines replace histones. Thus, the presence of triplex DNA in the chromatid scaffold correlates with the anchoring of expanded DNA loops to it. After loop retraction, the scaffolds of all chromatids coiled as a single unit in the spermatid head. This cooperative coiling produced enlargement and tilting of the distal telomeric signals, which were distributed along the spermatid head according to the length of each chromosome. We propose that specific DNA sequences dispersed throughout the whole chromatid fold forward and backward coaxially to chromatid length, forming individual scaffold modules whose linear assembly accounts for the minimum length of each individual chromatid. Finally, the core of the grasshopper male spermatid should be considered as a single chromosome in which the DNA scaffolds of the whole set of the nonhomologous chromosomes of the haploid complement are interconnected. This pattern of chromatin organization applies probably to other elongated spermatids.

Alkali-labile sites in sperm cells from Sus and Ovis species

Constitutive alkali-labile sites (ALSs) have been investigated using a protocol of DNA breakage detection-fluorescence in situ hybridization (DBD-FISH) in sperm cells from Sus domesticus (pig), Ovis gmelini musimon (mouflon) and Ovis aries (sheep). The results were compared with those obtained using leucocytes from the same species. Whole comparative genomic hybridization (W-CGH) showed that most of the constitutive ALSs in somatic and germ line cells in all species examined were constrained to particular repetitive satellite DNA sequences located in the pericentromeric constitutive heterochromatin of each chromosome. However, their relative abundance was different among cells of the same organism (leucocytes/sperm cells), and this trend was not maintained when the different species were compared. Thus, in mouflon, the density of ALSs in leucocytes when compared with that observed in sperm cells indicated abundance of the order of eight times less. In sheep, both leucocytes and sperm cells exhibited a large quantity of ALSs, being of the order of four times more abundant in sperm cells. In the pig genome, leucocytes showed a high abundance of ALSs (of the order of 12 times more that in sperm cells) but only involved the metacentric chromosomes of the karyotype. ALSs were not present in the acrocentric chromosomes. Contrary to mouflon and sheep, ALSs were relatively scarce in sperm cells from pig. These results suggest that ALSs are a transient structural feature in the cells of any organisms and point to a non-universal model of chromatin organization in sperm cells among mammals.

Whole-comparative genomic hybridization and "cell code" estimation: an application for assessment of cellular chimerism

Whole-comparative genomic hybridization (W-CGH) allows one to identify copy number differences in highly repeated DNAs between two genomes. It allowed the identification of nuclear markers that can be used to distinguish cell populations from different individuals in a chimeric situation. We discuss the reliability of W-CGH accomplished with fluorescent in situ hybridization (FISH) and digital image analysis (DIA) to analyze the degree of chimerism in patients after allogeneic hematopoietic stem cell transplantation (HSCT).

Evidence of modified nuclear protein matrix in human spermatozoa with fragmented deoxyribonucleic acid

Human spermatozoa were processed for determination of DNA fragmentation with use of an in situ diffusion assay, so that those cells containing DNA fragmentation produce extensive peripheral dissemination of DNA fragments after lysis in an agarose microgel. Quantification of specific protein staining confirmed that sperm cells without DNA fragmentation had almost complete removal of nuclear matrix proteins, whereas spermatozoa with DNA fragmentation tended to retain residual nucleoskeletal protein in a collapsed and condensed state. This result suggests that a modified nuclear protein matrix associates with fragmented sperm DNA.

Increased aneuploidy rate in sperm with fragmented DNA as determined by the sperm chromatin dispersion (SCD) test and FISH analysis

Previous studies suggest that sperm DNA fragmentation may be associated with aneuploidy. However, currently available tests have not made it possible to simultaneously perform DNA fragmentation and chromosomal analyses on the same sperm cell. The recently introduced sperm chromatin dispersion (SCD) test allows users to determine this relationship. Semen samples from 16 males, including 4 fertile donors, 7 normozoospermic, 3 teratozoospermic, 1 asthenozoospermic, and 1 oligoasthenoteratozoospermic, were processed for DNA fragmentation analysis by the SCD test using the Halosperm kit. Three-color fluorescence in situ hybridization (FISH) was performed on SCD-processed slides to determine aneuploidy for chromosomes X, Y, and 18. Spermatozoa with DNA fragmentation showed a 4.4 +/- 1.9-fold increase in diploidy rate and a 5.9 +/- 3.5-fold increase in disomy rate compared to spermatozoa without DNA fragmentation. The overall aneuploidy rate was 4.6 +/- 2.0-fold higher in sperm with fragmented DNA (Wilcoxon rank test: P < .001 in the 3 comparisons). A higher frequency of DNA fragmentation was found in sperm cells containing sex chromosome aneuploidies originated in both first and second meiotic divisions. The observed increase in aneuploidy rate in sperm with fragmented DNA may suggest that the occurrence of aneuploidy during sperm maturation may lead to sperm DNA fragmentation as part of a genomic screening mechanism developed to genetically inactivate sperm with a defective genomic makeup.

Interstitial telomeric sequence blocks in constitutive pericentromeric heterochromatin from Pyrgomorpha conica (Orthoptera) are enriched in constitutive alkali-labile sites

The long interstitial telomeric repeat sequence (ITRS) blocks located in the pericentromeric chromosomal regions of most of Chinese hamster chromosomes behave as hot spots for spontaneous and induced chromosome breakage and recombination. The DBD-FISH (DNA breakage detection-fluorescence in situ hybridization) procedure demonstrated that these ITRS are extremely sensitive to alkaline unwinding, being enriched in constitutive alkali-labile sites (ALS). To determine whether this chromatin modification occurs in other genomes with large ITRS that are not phylogenetically related to mammalian species, the grasshopper Pyrgomorpha conica was analyzed. We chose this species because, with conventional FISH, their chromosomes yield extremely small telomeric signals when probed with the (TTAGG)n polynucleotide, but large ITRS blocks as part of their pericentromeric constitutive heterochromatin. A high density of constitutive ALS was evidenced in the ITRS when intact meiotic cells or somatic cells were subjected to the DBD-FISH technique and probed with the specific telomeric DNA. DBD-FISH with simultaneous hybridization using telomeric and whole genome DNA probes showed that the ITRS tend to colocalize with areas of stronger signal from the whole genome probe. Nevertheless, the signal from the whole genome was more widespread than that from the ITRS, thus providing evidence that a high frequency of constitutive ALS was present in more than one DNA sequence type. Furthermore, stretched DNA fibers processed with DBD-FISH, revealed a distribution of telomeric sequences alternating interspersed with other possible highly repetitive DNA sequences. The abundance of ALS varied from one meiotic stage to another. Interestingly, most of the breakage and meiotic recombination in males takes place close to the constitutive heterochromatin, particularly enriched in ALS. These results provide further evidence of a particular, and possible universal, chromatin structure enriched in constitutive ALS at constitutive heterochromatic regions.

Infertile men with varicocele show a high relative proportion of sperm cells with intense nuclear damage level, evidenced by the sperm chromatin dispersion test

The frequency of sperm cells with fragmented DNA was studied in a group of 18 infertile patients with varicocele and compared with those obtained in a group of 51 normozoospermic patients, 103 patients with abnormal standard semen parameters, and 22 fertile men. The spermatozoa were processed to discriminate different levels of DNA fragmentation using the Halosperm kit, an improved Sperm Chromatin Dispersion (SCD) test. In this technique, after an acid incubation and subsequent lysis, those sperm cells without DNA fragmentation show big or medium-sized halos of dispersion of DNA loops from the central nuclear core. Otherwise, those spermatozoa containing fragmented DNA either show a small halo, exhibit no halo with solid staining of the core, or show no halo and irregular or faint stain of the remaining core. The latter, that is, degraded type, corresponds to a much higher level of DNA-nuclear damage. The varicocele patients showed 32.4% +/- 22.3% of spermatozoa with fragmented DNA, significantly different from the group of fertile subjects (12.6% +/- 5.0%). Nevertheless, this was not different from that of normozoospermic patients (31.3% +/- 16.6%) (P = .83) and with abnormal semen parameters (36.6% +/- 15.5%) (P = .31). No significant differences were found between the normozoospermic patients and the patients with abnormal semen parameters. Strikingly, the proportion of the degraded cells in the total of sperm cells with fragmented DNA was 1 out of 4.2 (23.9% +/- 12.9%) in the case of varicocele patients, whereas it was 1 out of 8.2 to 9.7 in the normozoospermic patients (11.1% +/- 9.9%) in the patients with abnormal sperm parameters (12.2% +/- 8.3%) and in the fertile group (10.3% +/- 7.2%). Thus, whereas no differences in the percentage of sperm cells with fragmented DNA were evident with respect to other infertile patients, individuals with varicocele exhibit a higher yield of sperm cells with the greatest nuclear DNA damage level in the population with fragmented DNA. This finding illustrates the value of assessing different patterns of DNA-nuclear damage within each sperm cell and the particular ability of the Halosperm kit to reveal them.

[Principles of the treatment of peritoneal carcinomatosis due to colorectal cancer. Current review and update]

Colorectal cancer is the most frequent digestive tumor. The incidence of abdominal dissemination is high and all studies of the natural history of colorectal carcinomatosis demonstrate that prognosis in these patients is poor, with a mean survival of between 5 and 9 months. Furthermore, the results of systemic adjuvant treatment are disappointing, with a maximum survival of 18 months. Consequently, other treatment strategies need to be studied and developed. We present a review of the principles that underlie Sugarbakers treatment protocol, which includes maximal cytoreductive surgery for the treatment of macroscopic disease through peritonectomy together with perioperative intraperitoneal intensification chemotherapy for residual microscopic disease. We present all the phase II studies with more than 10 treated patients published in the medical literature by the main groups working in this line of treatment, together with the only phase III study published to date. With this new therapeutic alternative, the mean overall survival at 2 and 5 years is 40% and 20% respectively. Based on these results, this new therapeutic approach is recommended as the treatment of choice in these unfortunate patients. The limits of the treatment of advanced colorectal cancer are also discussed.

Value of the sperm deoxyribonucleic acid fragmentation level, as measured by the sperm chromatin dispersion test, in the outcome of in vitro fertilization and intracytoplasmic sperm injection

OBJECTIVE

To determine the prognostic value of sperm DNA fragmentation levels, as measured by the sperm chromatin dispersion (SCD) test, in predicting IVF and ICSI outcome.

DESIGN

Double-blind prospective study.

SETTING

University-affiliated private IVF setting.

PATIENT(S)

A total of 85 couples undergoing infertility treatment with IVF/ICSI.

INTERVENTION(S)

Analysis of DNA fragmentation by the SCD test in 170 aliquots obtained from the ejaculate and from the processed semen used for assisted reproductive technologies (ART).

MAIN OUTCOME MEASURE(S)

Percentage of spermatozoa with fragmented DNA was statistically correlated with embryo quality and reproductive success.

RESULT(S)

Fertilization rate was inversely correlated with DNA fragmentation (r = -0.245 P = .045). Higher DNA fragmentation rate gave an increased proportion of zygotes showing asynchrony between the nucleolar precursor bodies of zygote pronuclei (73.8% vs. 28.8% P < .001). In addition, the slower embryo development and worst morphology on day 6 was correlated with higher sperm DNA fragmentation (47.7% vs. 29.4% P = .044). We also observed a negative correlation between DNA fragmentation and the implantation rate (r = -0.250 P = .042). However, SCD test values were not statistically different in cycles that resulted in a pregnancy compared with those that did not (33.2 vs. 28.2 and 32.4 vs. 34.7).

CONCLUSION(S)

This is the first report that describes a correlation between sperm DNA integrity, as measured by the SCD test, and fertilization rate, embryo quality, and implantation rate in IVF/ICSI. The degree of DNA fragmentation was inversely correlated with fertilization rate, synchrony of the nucleolar precursor bodies' pattern in pronuclei, embryo ability to achieve blastocyst stage, and embryo morphological quality. Because SCD test values were correlated with embryo quality and blastocyst rate, the lack of correlation between sperm DNA fragmentation and pregnancy outcome in IVF might be due to embryo selection before transfer. The ability of the SCD test to predict the blastocyst rate after IVF/ICSI warrants further study.

The genome project of Taenia solium

We have constituted a consortium of key laboratories at the National Autonomous University of Mexico to carry out a genomic project for Taenia solium. This project will provide powerful resources for the study of taeniasis/cysticercosis, and, in conjunction with the Echinococcus granulosus and Echinococcus multilocularis genome project of expressed sequence tags (ESTs), will mark the advent of genomics for cestode parasites. Our project is planned in two consecutive stages. The first stage is being carried out to determine some basic parameters of the T. solium genome. Afterwards, we will evaluate the best strategy for the second stage, a full blown genome project. We have estimated the T. solium genome size by two different approaches: cytofluorometry on isolated cyton nuclei, as well as a probabilistic calculation based on approximately 2000 sequenced genomic clones, approximately 3000 ESTs, resulting in size estimates of 270 and 251 Mb, respectively. In terms of sequencing, our goal for the first stage is to characterize several thousand EST's (from adult worm and cysticerci cDNA libraries) and genomic clones. Results obtained so far from about 16,000 sequenced ESTs from the adult stage, show that only about 40% of the T. solium coding sequences have a previously sequenced homologue. Many of the best hits are found with mammalian genes, especially with humans. However, 1.5% of the hits lack homologues in humans, making these genes immediate candidates for investigation on pharmaco-therapy, diagnostics and vaccination. Most T. solium ESTs are related to gene regulation, and signal transduction. Other important functions are housekeeping, metabolism, cell division, cytoskeleton, proteases, vacuolar transport, hormone response, and extracellular matrix activities. Preliminary results also suggest that the genome of T. solium is not highly repetitive.

Simple determination of human sperm DNA fragmentation with an improved sperm chromatin dispersion test

OBJECTIVE

To improve the sperm chromatin dispersion (SCD) test and develop it as a simple kit (Halosperm kit) for the accurate determination of sperm DNA fragmentation using conventional bright-field microscopy.

DESIGN

Method development, comparison, and validation.

SETTING

Medical genetics laboratory, academic biology center, and reproductive medicine centers.

PATIENT(S)

Male infertility patients attending the Reproductive Medicine Center. A varicocele patient and a group of nine fertile subjects.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

[1] The quality of chromatin staining in relaxed sperm nuclear halos and tail preservation; [2] SCD scoring reproducibility; [3] comparison with the sperm chromatin structure assay in 45 samples; [4] frequency of sperm with DNA fragmentation after incubation with increasing doses of the nitric oxide donor sodium nitroprusside and in sperm samples for 9 fertile men, 46 normozoospermic patients, 23 oligoasthenoteratozoospermic patients, and a subject with varicocele.

RESULT(S)

The sperm nuclei with DNA fragmentation, either spontaneous or induced, do not produce or show very small halos of DNA loop dispersion after sequential incubation in acid and lysis solution. The improved SCD protocol (Halosperm kit) results in better chromatin preservation, therefore highly contrasted halo images can be accurately assessed using conventional bright-field microscopy after Wright staining. Moreover, unlike in the original SCD procedure, the sperm tails are now preserved, making it possible to unequivocally discriminate sperm from other cell types. The chi2 test did not detect significant differences in the mean number of sperm cells with fragmented DNA as scored by four different observers. The intraobserver coefficient of variation for the estimated percentage of spermatozoa with fragmented DNA ranged from 6% to 12%. There was good correlation between the SCD and the sperm chromatin structure assay DNA fragmentation index (intraclass correlation coefficient R: 0.85; percent DNA fragmentation index mean difference: 2.16 significantly higher for SCD). Using the Halosperm kit, a dose-dependent increase in sperm DNA damage after sodium nitroprusside incubation was detected. The percentage of sperm cells with fragmented DNA in the fertile group was 16.3 +/- 6.0, in the normozoospermic group, 27.3 +/- 11.7, and in the oligoasthenoteratozoospermic group, 47.3 +/- 17.3. In the varicocele sample, an extremely high degree of nuclear disruption was detected in the population of sperm cells with fragmented DNA.

CONCLUSION(S)

The improved SCD test, developed as the Halosperm kit, is a simple, cost effective, rapid, reliable, and accurate procedure, for routinely assessing human sperm DNA fragmentation in the clinical andrology laboratory.

Halosperm is an easy, available, and cost-effective alternative for determining sperm DNA fragmentation

The characteristics of Halosperm make this kit a reasonable alternative to allow basic and clinical research on sperm DNA fragmentation in any basic laboratory around the world.

Critically short telomeres are associated with sperm DNA fragmentation

The influence of critical telomeric attrition, a well-known trigger of apoptosis and cell arrest, on sperm DNA fragmentation was studied in late-generation knockout mice for Terc, the RNA component of telomerase, as a model of choice. Terc knockout mice had a sixfold mean increase in the percentage of sperm cells with fragmented DNA.