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J Suominen

Publications and source records attributed to J Suominen.

At least 19 recordsLinked to original sources
PubMed2002

Time to pregnancy and semen parameters: a cross-sectional study among fertile couples from four European cities.

BACKGROUND: In fertile populations, little is known about the association between semen parameters and time to pregnancy (TTP). METHODS: Pregnant women from Copenhagen, Edinburgh, Paris and Turku who conceived without medical intervention were asked for their TTP (942 couples), and their partners provided a semen sample. The proportion of morphologically normal sperm and the multiple anomalies index (MAI, ratio of the total number of anomalies to the number of abnormal sperm) were centrally estimated. We estimated rate ratios for the occurrence of a pregnancy by a discrete survival model, adjusted for sexual activity and female factors affecting fecundity. RESULTS: Increasing sperm concentration influenced TTP up to 55 x 10(6)/ml. The proportion of morphologically normal sperm influenced TTP up to 39% according to David's criteria, and this association held among the subjects with a sperm concentration >55 x 10(6)/ml. For strict criteria, the threshold value was 19% normal sperm. An increase of 0.5 in MAI was associated with an adjusted rate ratio for the occurrence of a pregnancy of 0.68 (95% confidence interval: 0.54-0.85). CONCLUSIONS: These results highlight the importance of sperm morphology parameters and indicate that the effect of proportion of normal sperm on TTP may be independent of sperm concentration.

Cross-Sectional Studies↗
PubMed2001

Differential expression and regulation of the retinoblastoma family of proteins during testicular development and spermatogenesis: roles in the control of germ cell proliferation, differentiation and apoptosis.

Normal spermatogenesis is highly dependent on well-balanced germ cell proliferation, differentiation, and apoptosis. However, the molecular mechanisms that govern these processes are largely unknown. Retinoblastoma family proteins (pRb, p107 and p130) are potentially important regulators of cell growth, differentiation and apoptosis. pRb has been shown to be expressed in the rat testis and involved in the regulation of spermatogenesis. In the present study, the expression and localization of the other two pRb family members, p107 and p130, were analysed at both mRNA and protein levels during testicular development and spermatogenesis using Northern, Western blotting, immunohistochemistry, and in situ hybridization. Furthermore, changes of levels and phosphorylation status of pRb family proteins in response to growth suppression and/or apoptosis induction were investigated using a seminiferous tubule culture system and three animal models. Our data suggest that: (1) pRb family proteins are differentially expressed in the rat testis and they function in a cell-type-specific manner during testicular development and spermatogenesis; (2) they participate in the control of germ cell cycle and act in a cell cycle-phase-specific fashion during germ cell proliferation, and (3) they are also involved in the regulation of apoptosis of germ cells and Leydig cells.

Acetates↗
PubMed2001

Aneuploidy in spermatozoa of infertile men with teratozoospermia.

Recent studies have shown that aneuploidy in spermatozoa of infertile men with poor semen quality is increased. The purpose of this study was to determine whether poor sperm morphology is associated with the incidence of spermatozoa with numerical chromosome abnormalities. Semen samples from 20 infertile teratozoospermic men were studied using multicolour fluorescence in situ hybridization (FISH). Men were divided into four groups according to the proportion of normal sperm morphology: infertile men with <10% (group A, n=7), 10-19% (group B, n=6), and 20-29% (group C, n=7) of morphologically normal spermatozoa, and controls (group D, n=5) with > or =30% normal forms. Two hybridizations were performed. All the samples were analysed using probes for chromosomes 1 and 7 and, in addition, in group A and in controls with normal semen parameters probes for chromosomes X, Y and 18 were also used. Ten thousand spermatozoa were scored per hybridization. Severely teratozoospermic men (<10% normal forms) had significantly higher frequency of disomy 7, 18, YY, XY and diploidy in their spermatozoa when compared with controls. The results suggest that poor sperm morphology is associated with numerical chromosome abnormalities of spermatozoa. Severely teratozoospermic men may be at an increased risk of producing aneuploid offspring.

Adult↗
PubMed2001

Reassessment of sperm morphology of archival semen smears from the period 1980--1994.

Several reports have suggested that sperm counts of normal men have declined in many geographical regions during the last decades. Deterioration of sperm morphology has also been reported in some studies covering long sample collecting periods. The original semen analysis data of our semen laboratory from the period 1980--1994 showed a significant decline in the proportion of spermatozoa with normal morphology. The finding was, however, questioned because of changes in sperm morphology assessment criteria during the study period. In the present study 1745 smears were re-analysed to cover evenly the whole study period. The samples were examined in random order by using strict assessment criteria. Multiple linear regression analysis of the re-analysed data showed no effect of the year of sample delivery on sperm morphology between the years 1980 and 1994. However, there was a significant decline in the proportion of normal spermatozoa with later year of men's birth.

Adult↗
PubMed2001

Regional differences in waiting time to pregnancy among fertile couples from four European cities.

BACKGROUND: A previous European study found a longer time to pregnancy (TTP) among fertile women from Paris compared with women from other Western European countries. A co-ordinated, cross-sectional study of pregnant couples from Denmark (Copenhagen), France (Paris), Scotland (Edinburgh) and Finland (Turku) was therefore undertaken to assess differences in waiting TTP among couples from these cities. METHODS: Pregnant women were invited to participate when they showed up for their first antenatal visit in one of the four centres. Inclusion criteria included that their partner was 20-45 years of age and born in the country in which he was currently living and that the pregnancy was achieved without fertility treatment. Both partners filled in a questionnaire and the man underwent a physical examination and delivered a semen sample (Turku: n = 237, Copenhagen: n = 302, Edinburgh: n = 212, Paris: n = 191). RESULTS: French couples had a decreased probability of conception compared with couples from the other three countries, although only after adjustment for confounders. No significant differences between couples from the three other countries were found. CONCLUSION: The observed geographical differences in TTP remain unexplained and were not due to differences in semen quality, but may be caused by varying exposures to environmental factors or psychological distress. In addition, selection bias due to the low participation rates cannot be ruled out. Future studies examining the causes for geographical differences in TTP are needed.

Adult↗
PubMed2001

Sperm morphological defects related to environment, lifestyle and medical history of 1001 male partners of pregnant women from four European cities.

BACKGROUND: Recently, differences in semen quality have been found among the partners of pregnant women from four European cities: Turku, Copenhagen, Edinburgh and Paris. METHODS: During this study, slides from the four centres were subjected to a centralized assessment of sperm morphology. The percentages of sperm defects were recorded using a multiple-entry classification enabling the calculation of the multiple anomalies index (MAI), which is the mean number of anomalies per abnormal sperm. The relationships between various sperm abnormalities and self-reported data on medical history, lifestyle and occupational factors were examined. RESULTS: Significant differences in the MAI and most of the sperm defects were found between the four cities, and more abnormalities were found in spring than in winter. An increase in some sperm abnormalities was related to medical treatment of the mother during pregnancy, higher birthweight and previous treatment for cryptorchidism. Significant variations of several sperm defects were related to stress, weekly working time, occupational posture and metal welding, suggesting directions for further exposure studies. CONCLUSION: The present study indicated that the detailed assessment of sperm abnormalities is a useful biomarker of the effect of various external factors which may qualitatively affect human spermatogenesis.

Adult↗
PubMed2001

Regional differences in semen quality in Europe.

Recent reports have indicated a decrease in semen quality of men in some countries, and suggested regional differences. A study was undertaken of semen samples from 1082 fertile men from four European cities (Copenhagen, Denmark; Paris, France; Edinburgh, Scotland; and Turku, Finland). Semen analysis was standardized, inter-laboratory differences in assessment of sperm concentration were evaluated, and morphology assessment centralized. Lowest sperm concentrations and total counts were detected for Danish men, followed by French and Scottish men. Finnish men had the highest sperm counts. Men from Edinburgh had the highest proportion of motile spermatozoa, followed by men from Turku, Copenhagen and Paris. Only the differences between Paris/Edinburgh and Paris/Turku were statistically significant (P < 0.003 and P < 0.002 respectively). No significant differences in morphology were detected. A general seasonal variation in sperm concentration (summer 70% of winter) and total sperm count (summer 72% of winter) was detected. Semen quality of a 'standardized' man (30 years old, fertile, ejaculation abstinence of 96 h) were estimated. Typically, sperm concentrations (x 10(6)/ml) for winter/summer were: Turku 132/93; Edinburgh 119/84; Paris 103/73; and Copenhagen 98/69. These differences in semen quality may indicate different environmental exposures or lifestyle changes in the four populations. However, it remains to be seen whether such changes can account for these differences. These data may also serve as a reference point for future studies on time trends in semen quality in Europe.

Adult↗
PubMed2000

Involvement of Bcl-2 family proteins in germ cell apoptosis during testicular development in the rat and pro-survival effect of stem cell factor on germ cells in vitro.

A large part of germ cells die apoptotically during testicular development in rodents. In the present study, a wave of germ cell apoptosis was observed between days 10 and 30 of postnatal life by in situ 3'-end labeling and DNA fragmentation analysis. To explore the potential involvement of Bcl-2 family members in this process, the expression and localization of some Bcl-2 family proteins (Bcl-2, Bcl-xL, Bcl-w, Bak, Bax, and Bad) and p53 were analyzed during testicular development in the rat by Western blotting and immunohistochemistry. The dynamic changes in the expression profiles of Bcl-2 family proteins are consistent with a model in which germ cells are primed for apoptosis during the first cycle of spermatogenesis by de novo expression of the death effectors Bax and Bad in a p53-dependent manner and these proteins are prevented from triggering further apoptosis after the first spermatogenic cycle has been set up by anti-apoptotic Bcl-2 family proteins Bcl-xL and Bcl-w. To examine whether the pro-survival effect of stem cell factor (SCF) on germ cells in vitro is mediated by Bcl-2 family proteins, the correlation between the pro-survival effect of SCF on germ cells and the expression of the above-mentioned apoptosis-related gene products in the seminiferous tubules at stage XII of the epithelial cycle were also investigated using a tubular culture system. The data suggest that SCF supports germ cell survival during spermatogenesis by up-regulating pro-survival Bcl-2 family proteins, Bcl-w and Bcl-xL, and down-regulating pro-apoptosis Bcl-2 family proteins, e.g. Bax.

Animals↗
PubMed2000

Inter-observer variation in the results of the clinical andrological examination including estimation of testicular size.

Inter-observer variation in andrological examination by 10 clinical investigators from five Nordic and Baltic countries was investigated. In addition, information on intra-observer variation was obtained for six of the 10 investigators. Testicular size was measured using Prader's orchidometer and one of the investigators also performed an ultrasound estimate of testicular size. A highly significant difference (p < 0.001) between observers was found with an inter-observer error of 16% in estimating testicular size in 23 young men. The difference in the estimate tended to increase with increasing testicular size. There was no significant intra-observer difference in two measurements performed on consecutive days. Only differences in median testis size, which were greater than 31% between measurements by two investigators, were found to be significant at the 5% level. The ultrasound estimate of testicular size was significantly lower than the orchidometer estimate, with a mean difference of 3.6 mL for the left testis and 4.3 mL for the right testis. Tanner staging of genitalia and diagnosis of a varicocele was subject to great inter-observer variation, and for the diagnosis of varicocele only one-third of the investigators was able to reproduce their results on a second examination. In conclusion, it was found that the clinical andrological examination of young men is subject to great inter-observer variation. This should be kept in mind when results from different studies are compared as well as in daily clinical practice.

Adult↗
PubMed2000

Stem cell factor protects germ cells from apoptosis in vitro.

Stem cell factor (SCF) plays an important role in migration, adhesion, proliferation, and survival of primordial germ cells and spermatogonia during testicular development. However, the function of SCF in the adult testis is poorly described. We have previously shown that, in the presence of SCF, there were more type A spermatogonia incorporating thymidine at stage XII of rat seminiferous tubules cultured in vitro than in the absence of SCF, implying that the increased DNA synthesis might result from enhanced survival of spermatogonia. To explore the potential pro-survival function of SCF during spermatogenesis, the seminiferous tubules from stage XII were cultured in the presence or absence of SCF (100 ng/ml) for 8, 24, 48, and 72 hours, respectively, and apoptosis was analyzed by DNA laddering and in situ 3'-end labeling (ISEL) staining. Surprisingly, not only spermatogonia, but also spermatocytes and spermatids, were protected from apoptosis in the presence of SCF. Apoptosis took place much later and was less severe in the SCF-treated tubules than in the controls. Based on previous studies showing that FSH prevents germ cells from undergoing apoptosis in vitro, and that SCF level is increased dramatically in response to FSH stimulation, we also tested if the pro-survival effect of FSH is mediated through SCF by using a function-blocking monoclonal antibody, ACK-2, to block SCF/c-kit interaction. After 24 hours of blockade, the protective effect of FSH was partially abolished, as manifested by DNA laddering and ISEL analyses. The present study demonstrates that SCF acts as an important survival factor for germ cells in the adult rat testis and FSH pro-survival effect on germ cells is mediated partially through the SCF/c-kit pathway.

Animals↗
PubMed2000

Semen quality among Danish and Finnish men attempting to conceive. The Danish First Pregnancy Planner Study Team.

OBJECTIVE: To assess differences in semen quality between similar populations from Denmark and Finland. DESIGN: Comparison of semen quality between 221 Finnish men (of whom 115 had no proven fertility) and 411 Danish men with no proven fertility in two follow-up studies among normal couples trying to conceive. METHODS: In Finland male partners of couples without experienced infertility attempting to conceive were recruited through advertisements in local newspapers from 1984 to 1986. From 1992 to 1995 Danish men who lived with a partner and who had not attempted to achieve a pregnancy previously were recruited through their union when they discontinued birth control. All semen analyses were performed in accordance with the World Health Organization guidelines. RESULTS: Median sperm concentration, total sperm count and the percentage of morphologically normal spermatozoa were significantly higher among the Finnish men without proven fertility (104.0 million/ml, 304.0 million and 58% respectively) compared with the Danish men (53.0 million/ml, 140.8 million, and 41% respectively). Sperm concentration was 105.7% (95% confidence interval (CI) 58.1%-167.6%) and total sperm count was 127.4% (95% CI 71.4%-201.6%) higher among Finnish men without proven fertility than among Danish men after control for confounders. CONCLUSIONS: Some, but hardly all, of the observed difference in semen quality may be explained by differences in recruitment procedures, selection of the men and by methodological differences in semen analysis between the two countries. Also a birth cohort effect may explain some of the differences between countries as the Finnish men were recruited 11 years before the Danish men. Therefore, follow-up studies with identical recruitment and selection of men from the two countries are needed.

Adult↗
PubMed1999

Stage-specific regulation of stem cell factor gene expression in the rat seminiferous epithelium.

To assess the regulation of stem factor factor (SCF) gene expression during spermatogenesis, we tested the effects of hormones (FSH, testosterone, and 17beta-estradiol) and some growth factors [transforming growth factor-beta (TGF beta), TGF alpha, tumor necrosis factor-alpha, and activin] on SCF gene expression by using a transillumination-assisted microdisection technique, a seminiferous tubule culture system, and Northern hybridization. Our results showed that FSH (10 ng/ml) increased steady state levels of SCF messenger RNA (mRNA) in a stage-specific and time-dependent manner. 8-Bromo-cAMP could increase the SCF mRNA level in a similar way as FSH, whereas phorbol 12-myristate 13-acetate had no effect. Actinomycin D could abolish the stimulatory effect of FSH, whereas cyclohexamide could not. The half-life of SCF mRNA was apparently prolonged after FSH stimulation (FSH-treated tubules, 15.6 +/- 1.2 h; controls, 8.6 +/- 2.7 h). Nuclear run-on assay revealed 5- and 10-fold increases in the transcription rate after FSH stimulation for 8 and 30 h, respectively. Neither testosterone nor estradiol had significant effects on SCF gene expression in our tissue culture system. Activin, TGF beta, TGF alpha, and tumor necrosis factor-alpha had no effect on SCF gene expression in vitro. In conclusion, SCF gene expression in the rat seminiferous tubule is regulated by FSH through the cAMP/protein kinase A pathway. FSH regulates SCF gene expression at both transcriptional and posttranscriptional levels involving the increase in transcription rate and prolongation of half-life of SCF mRNA, but is independent of de novo protein synthesis.

Animals↗
PubMed1997

Semen analysis performed by different laboratory teams: an intervariation study.

Some recent studies have indicated that sperm concentration has decreased during the last 50 years. However, comparisons between laboratories have revealed that geographical differences seem to exist and that any decrease may not be global. One point of criticism concerning comparison of results from different laboratories has been that some of the discrepancies detected could reflect the lack of standardized methods used in the different laboratories. Four teams, each consisting of one physician and one technician from groups which have recently published data on semen quality, met in order to evaluate the variability between their laboratories on semen analysis. Twenty-six fresh semen samples from unselected men were analysed. The groups analysed the samples according to the normal practice in their laboratories, using their own equipment. The variation between laboratories was estimated through a random effects model. For sperm concentration and semen volume assessment a remarkable consistency between laboratories was detected, in contrast to the very considerable inter-individual variation. For sperm motility and morphology assessments interlaboratory consistency was much poorer. In conclusion, evaluation of sperm motility and morphology characteristics requires further standardization in order to achieve comparable data from different laboratories. However, semen volume and sperm concentration are characteristics which can be compared reliably between laboratories, when similar methodologies are used.

Adolescent↗
PubMed1997

Testicular fine needle aspiration cytology as a diagnostic tool in dog infertility.

The results of testicular aspirate cytology taken from clinical patients with a history of infertility were compared with the clinical and histological findings. Azoospermia was the most common and the most rewarding indication for the examination. Samples were also taken from cases with suspected testicular tumours, orchitis, epididymitis, severe oligo- and teratozoospermia, lack of libido and unilateral testicular atrophy. Histological and cytological findings were found to correlate well. Identification of cell types from normal germinal epithelium was relatively easy. No immediate adverse effects of aspiration were noted. Five normospermic dogs were monitored for two to six months after aspiration, and there were no marked deleterious effects on testicular consistency, testicular histology or semen characteristics. Testicular cytology obtained by fine needle aspiration may, at least to some extent, be used to assist clinical diagnosis, especially in azoospermic dogs and dogs with palpable changes of testicular tissue.

Animals↗
PubMed1996

High and unchanged sperm counts of Finnish men.

Several recent reports have suggested that the sperm counts of normal men are declining in most countries. In this study the sperm counts of Finnish men, and their possible changes during the past 28 years, were investigated. The material consisted of semen samples from 238 normal healthy men of unknown fertility and 5481 men from infertile couples. The means (medians) of semen volume, sperm density and total sperm count in normal men were 3.3 (3.0) ml, 133.9 (94.0) x 10(6)/ml and 396.6 (309.0) x 10(6), respectively. These parameters and the relative frequency distribution of the sperm density were similar to those reported elsewhere in the 1940s. Multiple linear regression analysis revealed a significant decrease in semen volume, whereas sperm density and total sperm count of infertile men had not changed significantly during the past 28 years. In addition, no change in sperm counts was associated with the year of men's birth.

Adult↗