Chromosomal abnormalities in sperm from testicular cancer patients before and after chemotherapy

Sperm chromosome abnormalities were assessed in testicular cancer patients before and after treatment with BEP (bleomycin, etoposide, cisplatin). The frequencies of disomy for chromosomes 1, 12, X, Y and XY were assessed along with diploid frequencies and sex ratios by multicolour fluorescence in situ hybridization (FISH). For each cancer patient, a minimum of 10,000 sperm was assessed for each chromosome probe before and after chemotherapy (CT). Data was analysed "blindly" by coding the slides. A total of 161097 sperm were analyzed, 80,445 before and 80,642 after treatment. The mean disomy frequencies were 0.11% pre-CT vs 0.06% post-CT for chromosome 1, 0.18% vs 0.15% for chromosome 12, 0.10% vs 0.9% for the X chromosome, 0.13% vs 0.10% for the Y chromosome and 0.25% vs 0.20% for XY sperm. There was no significant difference in the frequency of disomy pre-CT vs post-CT for any chromosome except that chromosome 1 demonstrated a significant decrease after CT. The "sex ratios" and frequency of diploid sperm were also not significantly different in pre and post-CT samples with 50.2% X-bearing sperm pre-CT and 50.5% X post-CT and 0.14% diploid sperm pre-CT vs 0.15% diploid sperm post-CT. There was no significant donor heterogeneity among the cancer patients. None of the values in the cancer patients differed significantly from 10 normal control donors. Thus our study suggests that BEP chemotherapy does not increase the risk of numerical chromosomal abnormalities in human sperm.

Use of intravascular ultrasound in evaluating repeated balloon rupture during coronary stenting

Balloon rupture during coronary angioplasty is a well-recognized complication of PTCA. Coronary angiography commonly fails to elicit the cause of balloon perforation. We present a case with multiple balloon rupture during additional high-pressure inflations of a Palmaz-Schatz stent where intravascular ultrasound was useful in revealing a calcified lesion protruding through the struts of the stent.

Reliability of estimates of diploid human spermatozoa using multicolour fluorescence in-situ hybridization

Multicolour fluorescence in-situ hybridization (FISH) analysis permits distinction between disomic and diploid spermatozoa. Thus estimates of the frequency of diploid spermatozoa can be obtained for human semen samples. The issue of the accuracy and reliability of these diploidy estimates has been addressed by analysing diploidy frequencies in 10 men using the same sperm sample to estimate diploidy twice-once during two-colour FISH analysis of disomy for chromosomes 1 and 12 and a second independent analysis of three-colour FISH for disomy estimates for chromosomes X and Y (with chromosome 1 used as the autosomal control). A minimum of 10,000 spermatozoa per hybridization per male was counted for a total of over 200,000 spermatozoa analysed. The mean frequency of diploid spermatozoa was 0.13% for the autosomal study and 0.14% for the sex chromosomal study, which were not significantly different. One donor had extremely divergent values of diploidy in the two studies. Analysis of values in the other nine donors demonstrated no significant difference in the two diploidy estimates. These results indicate that the FISH technique is an accurate and reliable method for determining diploid frequencies in human spermatozoa.

Testosterone induces dilation of canine coronary conductance and resistance arteries in vivo

BACKGROUND

Although estrogens have been shown to be vasoactive hormones, the vascular effects of testosterone are not well defined. Like estrogen, testosterone causes relaxation of isolated rabbit coronary arterial segments. We examined the vasodilator effects of testosterone in vivo in the coronary circulation and the potential mechanisms of its actions.

METHODS AND RESULTS

Using simultaneous intravascular two-dimensional and Doppler ultrasound, we examined the effect of intracoronary testosterone in coronary conductance and resistance arteries in 10 anesthetized dogs (5 male, 5 female). We also assessed the contribution of NO, prostaglandins, ATP-sensitive K+ channels, and classic estrogen receptors to testosterone-induced vasodilation. Testosterone induced a significant increase in cross-sectional area, average coronary peak flow velocity, and calculated volumetric coronary blood flow at the 0.1 and 1 mumol/L concentrations. This effect was independent of sex. Pretreatment with N omega-nitro-L-arginine methyl ester to block NO synthesis decreased testosterone-induced increase in cross-sectional area, average coronary peak flow velocity, and coronary blood flow. Pretreatment with glybenclamide to assess the role of ATP-sensitive K+ channels did not influence testosterone-induced dilation in epicardial arteries but did attenuate its effect in the microcirculation. Pretreatment with indomethacin or the classic estrogen-receptor antagonist ICI 182,780 did not alter testosterone-induced changes.

CONCLUSIONS

Short-term administration of testosterone induces a sex-independent vasodilation in coronary conductance and resistance arteries in vivo. Acute testosterone-induced coronary vasodilation of epicardial and resistance vessels is mediated in part by endothelium-derived NO. ATP-sensitive K+ channels appear to play a role in the vasodilatory effect of testosterone in resistance arteries.

Transesophageal echocardiography in fetal sheep. A monitoring tool for open and fetoscopic cardiac procedures

BACKGROUND

Cardiac procedures in exteriorized fetuses or assisted by fetoscopy require monitoring capabilities not attended by conventional maternal transabdominal echocardiography.

METHODS

We, therefore, assessed the potential of fetal transesophageal echocardiography (TEE) utilizing an intravascular ultrasound catheter (IVUC) for fetal cardiac monitoring. We inserted a 10-F-10-MHz IVUC into the esophagus in 12 exteriorized fetal sheep and by a fetoscopic approach in 4 fetal sheep. Cardiac events were observed. Heart rate, cardiac rhythm, patency of the foramen ovale and ductus arteriosus, and the width of the branch pulmonary arteries could be assessed in all fetuses. Ventricular contractility could be assessed only in fetuses weighing less than 2.5 kg. Larger fetuses did not allow adequate imaging of the apical portion of the ventricles because of limited tissue penetration of the IVUC. Fetal TEE permitted placing small guide wires in the cardiac atria and left ventricle. Short-lived premature beats following intracardiac manipulations of these wires could be observed by fetal TEE in all cases.

RESULTS

At autopsy, no complications from IVUC insertion were observed in the exteriorized fetuses. Fetoscopic placement of the IVUC resulted in minor perioral skin erosion in two nonexteriorized fetuses.

CONCLUSIONS

In conclusion, fetal TEE can be achieved with minor fetal injury and may provide useful information during open and fetoscopic cardiac procedures. Further improvements in IVUC design will permit the application of this technique to monitor human fetal cardiac procedures.

The relationship between paternal age, sex ratios, and aneuploidy frequencies in human sperm, as assessed by multicolor FISH

We studied the frequencies of X- and Y-chromosome-bearing sperm, diploidy and disomy for chromosomes 1, 12, X, and Y in sperm from 10 normal men aged 21-52 years, to determine whether there was any relationship between donor age and any of these variables. Multicolor FISH was used to control for lack of probe hybridization and to distinguish diploid sperm from disomic sperm. A minimum of 10,000 sperm per donor was evaluated for each chromosome, for a total of 225,846 sperm studied. Sperm were considered disomic if two fluorescent signals were separated by a minimal distance of one signal domain. The mean frequencies of X- and Y-bearing sperm were 50.1% and 49.0%, respectively; not significantly different from 50%. There was no correlation between paternal age and "sex ratio" in sperm. Similarly, there was no association between the frequency of diploid sperm (mean, .16%; range, .06-.42%) and donor age. For disomy frequencies, there was no relationship between donor age and disomy 12 (mean, .16%; range, .10%-.25%), XX (mean, .07%; range, .03%-.17%), and XY sperm (mean, .16%; range, .08%-.24%). There was a significant increase in the frequency of YY sperm (P = .04; mean, .18%; range, .10%-.43%) and disomy 1 sperm (P = .01; mean, .11%; range, .05%-.18%) with donor age. In summary, our results do not support a correlation between paternal age and sex ratio or diploidy.

Analysis of sperm chromosome complements from a man heterozygous for a pericentric inversion of chromosome 1

Human sperm chromosomes were studied in a man heterozygous for a pericentric inversion of chromosome (1)(p31q12). Q-banded pronuclear chromosomes were analyzed after in vitro penetration of golden hamster oocytes. A total of 159 sperm were examined: 54% bearing the inverted chromosome 1 and 46% the normal chromosome 1. These frequencies are not significantly different from the theoretical 1:1 ratio. There were no recombinant sperm with duplications or deficiencies, suggesting that a pairing loop failed to form or that crossing-over was suppressed. The frequency of abnormalities unrelated to the inversion was 5% for numerical, 8.8% for structural, 2.5% for numerical and structural, values not significantly different from control donors studied in our lab. The frequencies of X- and Y-bearing sperm were 46% and 54%, respectively, not significantly different from the expected value of 50%. This is the fifth pericentric inversion studied by human sperm chromosome analysis; recombinant chromosomes have been observed in two of the five cases. Some of the factors associated with an increased risk of recombinant sperm appear to be inversion size greater than 30% of the chromosome and chromosome breakpoints in G-light bands.

Detection of aneuploidy in human sperm by fluorescence in situ hybridization (FISH): different frequencies in fresh and stored sperm nuclei

Fluorescence in situ hybridization (FISH) with chromosome-specific repetitive DNA probes provides a new method for rapid detection of aneuploidy in human sperm. There is widespread interest in this technique for basic research, as well as for screening men exposed to potential aneugens. A number of laboratories have reported a wide range in the frequency of aneuploidy for chromosomes in human sperm, suggesting that FISH may not reflect the true frequency accurately. We have serendipitously discovered that the length of time that fixed frozen sperm nuclei are stored affects both the hybridization efficiency and disomy frequency of individual chromosomes. This may explain some of the variation in the aneuploidy frequencies observed among laboratories.

Detection of aneuploidy in human interphase spermatozoa by fluorescence in situ hybridization (FISH)

Fluorescence in situ hybridization (FISH) with repetitive-sequence DNA probes was performed on human interphase sperm to determine the utility of this technique for aneuploidy detection. DNA sequences specific for chromosomes 15 and 16 and the Y were biotinylated and hybridized with human sperm that had been treated with cetyltrimethylammonium bromide and dithiothreitol to render them accessible to the probes. Fluoresceinated avidin and antiavidin were utilized to visualize bound probe. More than 10,000 sperm were analyzed for each chromosome probe. The hybridization efficiency was 98-99% for all three probes. The frequencies for disomy (i.e., for nuclei containing two fluorescent signals) for chromosomes 15 and 16 and the Y were 0.14%, 0.17%, and 0.11%, respectively. These frequencies are all somewhat higher than those obtained by the human sperm karyotyping technique. Nevertheless, these preliminary results suggest that FISH is a simple and rapid technique that may provide an accurate screen for aneuploidy detection in human sperm.

A comparison of the frequency and type of chromosomal abnormalities in human sperm after different sperm capacitation conditions

Human sperm karyotypes can be prepared after fusion of human sperm with Golden hamster oocytes. Most laboratories use one of two methods of sperm capacitation: incubation of freshly-ejaculated sperm in Biggers, Whitten, and Whittingham (BWW) medium for 5-7 h at 37 degrees C or sperm storage in (N-tris [hydroxymethyl]methyl-2-aminoethanesulfonic acid; 2-([2-hydroxy-1,1-bis(hydroxymethyl)ethyl]amino)ethanesulfonic acid) (TES)-Tris yolk buffer (TYB) for 1-3 days at 4 degrees C. Since there have been conflicting reports as to whether there is a difference in the frequency of structural chromosomal abnormalities between BWW capacitation and storage in TYB for 2 days, we analyzed a larger number of karyotypes (8974) from 136 donors to determine if there was any difference in the frequency or type of chromosomal abnormalities in sperm treated by fresh BWW capacitation, storage in TYB for 1 day (TYB-1), or storage in TYB for 2 days (TYB-2). There was no difference in the frequency of numerical chromosomal abnormalities or sex ratio in any of the three treatment groups. However, there was a significantly increased frequency of structural chromosomal abnormalities after storage in TYB-1 and TYB-2. There was no difference in the frequency or type of structural chromosomal abnormalities after sperm storage in TYB-1 compared to TYB-2.

Analysis of sperm chromosome complements from a man heterozygous for a robertsonian translocation 45,XY,t(15q;22q)

Chromosome complements were studied in 118 sperm from a man heterozygous for a 15;22 Robertsonian translocation using the human sperm/hamster oocyte fusion technique. Alternate segregation occurred in most spreads (89.6%) and the proportion of normal (42.6%) and balanced complements (47%) was approximately equal. The frequency of sperm that were unbalanced with respect to the translocation was 10.4% and all categories of unbalanced sperm were observed (-15, -22, +15, +22). The frequency of chromosome abnormalities unrelated to the translocation was 7.6%. Since the frequencies of both numerical (3.4%) and structural abnormalities (3.4%) were within the normal range of control donors, there was no evidence for an interchromosomal effect. The frequencies of X-chromosome bearing (48%) and Y-chromosome bearing (52%) sperm were not significantly different from 50%. Data on this translocation were compared to the 4 other reports of cytogenetic analysis in sperm of Robertsonian translocation carriers.

Distribution of aneuploidy in human gametes: comparison between human sperm and oocytes

The frequency and distribution of aneuploidy was compared in 11,615 karyotyped human sperm and 772 karyotyped human oocytes to determine if all chromosomes are equally likely to be involved in aneuploid events or if some chromosomes are particularly susceptible to nondisjunction. The frequency of hypohaploidy and hyperhaploidy was compared among different chromosome groups and individual chromosomes for human sperm and oocytes. In general, hypohaploid chromosome complements were more frequent than hyperhaploid complements, in sperm and oocytes. The distribution of chromosome loss in the hypohaploid complements indicated that significantly fewer of the large chromosomes and significantly more of the small chromosomes were lost, suggesting that technical loss predominantly affects small chromosomes. A conservative estimate of aneuploidy (2 X hyperhaploidy) was approximately 3-4% in the human sperm and 18-19% in human oocytes. All chromosome groups were represented among hyperhaploid human sperm and oocytes. For human sperm, the observed frequency of hyperhaploidy equaled the expected frequency based on the assumption that the frequency of nondisjunction is equal for all chromosome groups, with two exceptions: group G and the sex chromosomes. Among individual chromosomes in human sperm, chromosomes 1 and 21 and the sex chromosomes had a significant excess of hyperhaploidy. For human oocytes, there were fewer hyperhaploid oocytes than expected for chromosome groups C and F and more than expected for chromosome groups D and G. Among individual chromosomes there was a significant excess for chromosome 21. These results indicate that all chromosomes are susceptible to nondisjunction but that chromosome 21 is particularly prone to aneuploidy in both human sperm and oocytes. They also demonstrate that sex chromosome aneuploidy is common in human sperm but not in human oocytes.

Cytogenetic analysis of 400 sperm from three translocation heterozygotes

Sperm chromosome complements were studied in three men who carried reciprocal translocations. A total of 400 sperm were karyotyped after in vitro penetration of hamster eggs: 217 sperm from t(2;9) (q21;p22), 164 from t(4;6)(q28;p23) and 19 from t(7;14) (q21;q13). All possible 2:2 and 3:1 meiotic segregations were observed for t(2;9) and t(4;6); for t(7;14) only 2:2 segregations were observed. For alternate segregations, the number of normal sperm was not significantly different from the number of sperm carrying a balanced form of the translocation in any of the translocations, as theoretically expected. The percentage of sperm with an unbalanced form of the translocation was 57% for t(2;9), 54% for t(4;6) and 47% for t(7;14). There was no evidence for an interchromosomal effect in any of the translocations since the frequencies of numerical abnormalities (unrelated to the translocation) were within the normal range of control donors. The frequencies of X- and Y-bearing sperm did not differ significantly from 50%. Results from a total of 17 reciprocal translocations studied by sperm chromosomal analysis were reviewed.

[Surgical treatment of hypoplastic left heart syndrome: a successful case report]

A successful case of Norwood operation for a 5-day-old infant with hypoplastic left heart syndrome is reported. Norwood procedure and central shunting with a 4 mm PTFE tube was performed. Cerebral and coronary artery were perfused independently during reconstruction of aorta in order to shorten the time of circulatory arrest. Post operative UCG documented un-obstructive systemic output from the right ventricle, well regulated pulmonary arterial blood flow and widely patent interatrial communication. This baby was discharged the hospital 66 days after surgery. He has been clinically well for six month after the operation.

Sperm chromosome analysis in a man heterozygous for a reciprocal translocation 46,XY t(12;20)(q24.3;q11)

Sperm chromosome complements were studied in a man who carried a reciprocal translocation t(12;20)(q24.3;q11). A total of 113 spermatozoa were karyotyped after in-vitro penetration of hamster eggs. 2:2 and 3:1 meiotic segregations were observed with the following frequencies: alternate 47%, adjacent 1 42%, adjacent 2 10%, 3:1 2%. For alternate segregations, the number of normal spermatozoa (25) was not significantly different from the number of spermatozoa carrying a balanced form of the translocation (28), as theoretically expected. The proportion of spermatozoa with an unbalanced form of the translocation was 53%. There was no evidence for an interchromosomal effect since the frequencies of numerical and structural abnormalities (unrelated to the translocation) were within the normal range of control donors.

Effect of culture conditions and media on the frequency of chromosomal abnormalities in human sperm chromosome complements

Human sperm chromosomes can be visualized after fusion with hamster eggs. Most laboratories use one of two methods of sperm treatment for capacitation: incubation in a modified Krebs-Ringer medium (BWW) for 5-7 h at 37 degrees C or storage in a TES-Tris yolk buffer (TYB) for 24-72 h at 4 degrees C. To determine whether data from the two methods were comparable, we performed a series of controlled experiments on one normal donor in which ejaculates were split and one aliquot of sperm was capacitated in BWW for 5-7 h at 37 degrees C (fresh) and the second aliquot was capacitated in TYB for 48 h at 4 degrees C (TYB). After capacitation, the technique used to obtain human sperm chromosome complements was identical for both aliquots. Both fresh and TYB sperm were further subdivided into two groups, which were subjected to either a short (1 h) or a long (3 h) gamete coincubation in BWW. This experiment was performed to determine if the longer incubation in BWW might induce chromosomal fragile sites and breaks because of nutritional depletion of the medium. A total of 458 human sperm chromosome complements was analysed. There was no significant difference in the frequency of sperm chromosomal abnormalities or in the sex ratio in the sperm coincubated with eggs for a short (1 h) or long (3 h) time in BWW. When sperm pretreatments were compared, there was a significant increase in the frequency of total sperm chromosomal abnormalities after TYB storage compared to fresh treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Human sperm chromosome complements after microinjection of hamster eggs

A technique was developed for microinjection of human spermatozoa into golden hamster (Mesocricetus auratus) eggs to obtain human pronuclear chromosome complements. Before microinjection the spermatozoa were treated by brief sonication or incubation in TEST-yolk buffer to reduce motility. Very few sperm chromosome complements developed after sperm treatment with sonication and the frequency of spermatozoa with structural chromosomal abnormalities was exceedingly high (91%). The majority of sperm chromosome complements analysed had multiple breaks and rearrangements. Sperm incubation in TEST-yolk buffer before microinjection provided more analysable sperm karyotypes with a significantly lower frequency of structural chromosomal abnormalities (39%, P less than 0.001). Our results therefore suggest that sonication induces structural chromosomal abnormalities in spermatozoa. Since the frequency of chromosomal abnormalities after microinjection was higher than after sperm fertilization of hamster eggs, it appears that microinjection per se may also increase the frequency of chromosomal abnormalities in spermatozoa. These results are based on small numbers and must be confirmed on larger sample sizes, but our study suggests that microinjection of spermatozoa into eggs should not be recommended for clinical use until fully evaluated.