PubMed Health⌕ Search

Biomedical subjects

L Björndahl

Publications and source records attributed to L Björndahl.

At least 19 recordsLinked to original sources

Development of a novel home sperm test.

BACKGROUND: The majority of men find the production of a semen sample an embarrassing and stressful experience. Consequently, the availability of an over-the-counter home sperm test, which would reliably and accurately allow the patient to obtain an assessment of fertility potential at their convenience, would be a major benefit. Our objective was to develop and evaluate a home sperm test that provides a visual estimate of the concentration of progressively motile sperm in a semen sample. METHODS: Three particular challenges are described (i) developing a visualization system; (ii) optimization of the detection limit; and (iii) controlling variation due to changes in ambient temperature. The accuracy of the device was tested against two reference methods: computer-assisted sperm analysis (CASA) and a hyaluronate migration test (HMT). RESULTS: In 129 semen samples, where both reference methods agreed (positive or negative), the accuracy of the device was 95%. The observed likelihood ratio of 8.8 indicated that a sample showing a red line in the device was over eight times more likely to have a positive (normal) result in CASA and HMT than a sample without a red line. CONCLUSIONS: The final device provides a visual estimate of the concentration of progressively motile sperm in a semen sample using a test that is completed within approximately 1 h of production of the sample and can be used by the man in the comfort of his own home.

Humans↗

Evaluation of the one-step eosin-nigrosin staining technique for human sperm vitality assessment.

BACKGROUND: The one-step eosin-nigrosin staining technique for assessment of sperm vitality was developed in the 1950s for various mammalian species. Although commonly used on human sperm in semen, a validation for this use has not previously been published. METHODS: The technique was evaluated on 1235 consecutive semen samples. RESULTS: The one-step eosin-nigrosin staining technique gave valid results when evaluated with sperm motility data obtained according to World Health Organization standard (1992, 1999). The mean for the sums of stained (i.e. supposedly dead) and motile sperm using the one-step eosin-nigrosin technique was 91% (SD +/- 10%). The distribution of sums for percentage stained and percentage motile sperm was similar, regardless of whether the samples had many or few dead sperm. CONCLUSIONS: Standardization and quality control of basic semen analysis demands robust, reliable and simple techniques that are easy to learn, and easy to continue to perform in the same way. The one-step eosin-nigrosin technique does not need negative phase contrast optics but can be run with ordinary bright-field microscopy. Since it also includes fewer methodological steps to control, it seems preferable in terms of standardization and quality control management. It should therefore be recommended in the basic semen analysis when sperm vitality is to be assessed.

Aniline Compounds↗

Semen analysis and external quality control schemes for semen analysis need global standardization.

One semen analysis laboratory [the Institute of Reproductive Medicine (IRM), Münster, Germany] was enrolled in three external quality assurance programmes in Europe (United Kingdom External Quality Assurance Scheme, European Academy of Andrology, European Society of Human Reproduction) that control for the assessment of sperm concentration, sperm motility and sperm morphology. Agreement between the participating laboratory and the sperm concentrations designated by all three programmes was good. Disagreement between two quality control (QC) programmes providing motility assessment was particularly noticeable in the distinction between motility grades a and b. For the identification of normal sperm morphology, marked differences between the standards set by different QC programmes were apparent. One programme was stricter in its categorization of normal forms, such that an overestimation of normal forms was diagnosed at IRM, whereas agreement with the other programmes was achieved. Variation of results from technicians in the IRM internal QC programme was <13%. The discrepancies between external quality control (EQC) centres demonstrated here are challenging problems to be overcome partly by the andrology laboratories and partly by the providers of EQC services. The introduction of objective, computer-aided sperm assessment in providing designated values may help to rectify this situation. Until this is achieved, EQC programmes should develop an internal programme to monitor their materials and methods for assessment.

Humans↗

ESHRE basic semen analysis courses 1995-1999: immediate beneficial effects of standardized training.

BACKGROUND: Many reports have shown problems with the high variability in results of semen analyses. The Special Interest Group in Andrology (SIGA) of the European Society of Human Reproduction and Embryology (ESHRE) implemented a standardized training course which has been run in different regions of the world on more than 20 occasions since 1994. The aim of the present analysis was to investigate to what extent training resulted in any immediate effects on the variability of assessments made by different observers. METHODS: The variability in participants' results from the beginning to the end of each course was analysed in eight courses given between 1995 and 1999. RESULTS: For assessments of sperm concentration, motility, vitality and morphology, substantial improvement was seen over the duration of the course. CONCLUSIONS: A comprehensive, structured training course does lead to substantial reductions in inter-observer variability in semen analysis. This supports our contention that providing a thorough theoretical background and repeated practical training, combined with daily feedback of results, is highly effective in raising the technical skills of laboratory personnel performing semen analysis.

Cell Survival↗

Sperm chromatin stability and zinc binding properties in semen from men in barren unions.

Sperm chromatin stability and zinc binding properties were studied in semen samples from 115 men living in barren unions. Of these men, 26% had a high proportion of swelling sperm, i.e. less than 80% sperm with stable chromatin after exposure to the detergent sodium dodecyl sulphate. From 2-67% of seminal zinc was bound to high molecular weight ligands of vesicular origin (HMW). This shows that, among infertile men, liquefied seminal plasma has huge variations in zinc chelating properties. The relationship between prostatic palpatory status, the proportion of abnormal sperm, the percentage zinc bound to HMW (HMW-Zn), the time between ejaculation and analysis and chromatin stability were studied. Samples with low chromatin stability were found more frequently in men with low HMW-Zn levels in semen. The proportion of stable sperm decreased in samples with prolonged exposure to seminal plasma. Neither the proportion of stable sperm heads nor the percentage zinc bound to HMW could be used to predict the future chances of the infertile men fathering children when studied 15-180 min after ejaculation. To differentiate between initial zinc-dependent stability and superstability developed in seminal plasma, other more sensitive methods must be developed.

Chromatin↗

Ejaculatory sequence in men with low sperm chromatin-zinc.

The composition of seminal plasma in the sperm-rich split ejaculate fraction was studied in a group of men with a low zinc content in their sperm chromatin, to evaluate the availability of zinc at ejaculation. Men with low-chromatin zinc had, in the sperm-rich split-ejaculate fraction, high amounts of seminal-vesicular fluid, a low zinc:fructose molar ratio, and a high percentage of zinc bound to high molecular weight ligands of seminal vesicular origin (HMW-Zn). This indicates premature admixture of vesicular fluid at ejaculation. It is suggested that the zinc:fructose molar ratio and HMW-Zn in the sperm-rich fractions could be used as a measure of the availability of zinc in seminal plasma.

Adult↗

Influence of seminal vesicular fluid on the zinc content of human sperm chromatin.

Chromatin zinc was studied using X-ray microanalysis of spermatozoa obtained from split-ejaculate fractions. Chromatin zinc, expressed as intensity ratio between zinc and sulphur (Zn/S), was unrelated to seminal zinc concentration, but was related inversely to markers of seminal vesicular secretion (fructose concentration and the proportion of zinc bound to ligands of seminal vesicular origin). It is concluded that the content of zinc in sperm chromatin can be reduced by the action of zinc ligands of seminal vesicular origin. An abnormally high contribution of seminal vesicular fluid to sperm-rich fractions of the ejaculate thus creates a risk of depleting chromatin zinc and thereby impairing zinc-dependent chromatin stability.

Adult↗

Seminal fluid from men with agenesis of the Wolffian ducts: zinc-binding properties and effects on sperm chromatin stability.

Zinc-binding properties were studied in 'prostatic fluid', i.e. in seminal plasma from patients with agenesis of the Wolffian ducts, and in split-ejaculate fractions dominated by seminal vesicular fluid. The effect of seminal fluid, with different zinc-binding properties, on the stability of zinc-dependent sperm chromatin was assessed by exposing sperm to 1% sodium dodecyl sulphate (SDS) for 60 min. Citrate was the only zinc ligand in 'prostatic fluid', as revealed by gel chromatography. Zinc in this fluid enhanced the stability of sperm chromatin. In contrast, the stability of sperm chromatin was decreased in seminal plasma dominated by vesicular fluid. These results are in accordance with the concept that prostatic fluid ensures the appropriate zinc content and stability of sperm chromatin, whereas abundance of vesicular fluid may jeopardize chromatin stability by reducing chromatin zinc content.

Chromatin↗

Changes in human sperm chromatin stability during preparation for in-vitro fertilization.

This study was designed to define the effects of sperm preparation on sperm chromatin stability in relation to in-vitro fertilization (IVF). Semen samples used for IVF-embryo transfer (ET) in the treatment of infertility due to tubal factors were studied. Cases with semen variables below reference limits in previous samples were excluded. Sperm were prepared by a swim-up technique employing either of two different tissue culture media, Ham's F-10 or Earle's balanced salt solution. Sperm chromatin stability was tested by exposure both to sodium dodecyl sulphate (SDS) only and SDS together with a zinc-chelating agent, disodium ethylene diamine tetraacetate (SDS-EDTA). Sperm head swell scores were defined under different experimental conditions and the relationship to sperm motility, morphology, fertilization rate and pregnancy occurrence was tested. No differences were seen between the chromatin stability of sperm from the original sample and that after swim-up preparation, neither immediately after completion of the swim-up procedure, nor at the time of insemination of ova. With time, the chromatin became more stable, which occurred to a similar extent both in the original sample and in swim-up preparations using Ham's F-10. Otherwise, sperm chromatin stability was unaffected by either of the two media used for swim-up. At higher incubation temperatures, decondensation in SDS was enhanced. Altogether, no correlation was found between sperm chromatin stability or enhancement of decondensation by temperature and the success of IVF treatment expressed in fertilization rates or pregnancies. The results are reassuring in that only small changes in sperm chromatin stability occurred during the preparation for IVF. As long as semen of presumably good quality is used, these changes in chromatin stability do not seem to be of clinical importance.

Chromatin↗

Zinc in sperm chromatin and chromatin stability in fertile men and men in barren unions.

The stability and the content of zinc of the chromatin were studied in spermatozoa from ten men with unexplained infertility, and in spermatozoa from five fertile donors. A positive relation was found between zinc in sperm nuclei (X-ray microanalysis) and the resistance of the chromatin to decondense in sodium dodecylsulfate (SDS). The infertile men had lower degree of sperm chromatin stability and lower sperm zinc content than the fertile donors. A subgroup of the infertile men, which all had minor clinical signs of prostatic inflammatory reaction, had the lowest content of zinc in the chromatin and the lowest degree of chromatin stability. A low content of nuclear zinc would impair the structural stability of the chromatin and thereby increase the vulnerability of the male genome. This mechanism may be one explanation for the reduced fertility of the men with minor inflammation of the prostate.

Chromatin↗

Cadmium interacts with the zinc-dependent stability of the human sperm chromatin.

Zinc normally participates in the stabilization of the chromatin of human spermatozoa, which have a high content of zinc after ejaculation. Sperm chromatin, depleted of zinc with EDTA, regained stability in the detergent SDS after exposure to Cd2+ in vitro. This effect was reversible with EDTA, but albumin could not reverse the stabilization caused by Cd2+ to the same extent as it reversed the stabilization caused by Zn2+.

Cadmium↗

Sperm nuclear zinc, chromatin stability, and male fertility.

Zinc excreted from the human prostate secures a high content of zinc in the sperm nucleus and contributes to the stability of the quaternary structure of the chromatin. After ejaculation, in vitro, a second type of stability, most probably involving disulfide-bridge crosslinks, supersedes the zinc-dependent stability. Normally, the nucleus of the ejaculated spermatozoon remains stable, i.e., it does not decondense when exposed to a detergent (e.g., sodium dodecyl sulfate - SDS), whereas a spermatozoon which has been exposed to a zinc-chelating medium becomes destabilized and decondenses in SDS. Spontaneous decondensation in SDS, i.e., without prior treatment with zinc-chelators, occurs among many spermatozoa from some infertile men, especially men with impaired secretory function of the prostate. This indicates that spontaneously decondensing spermatozoa have an inadequate content of zinc at ejaculation. Here, zinc in the sperm nucleus and chromatin stability was studied in semen samples from a group of men living in marriages with hitherto unexplained cause for infertility, and a group of fertile donors, who participated in an insemination program. Sperm nuclear zinc was studied with X-ray microanalysis and chromatin stability was assessed as percentage spermatozoa with stable sperm heads after exposure to SDS. Fertile donors had higher content of zinc in the sperm nuclei and had also higher proportions spermatozoa with a stabilized chromatin, than had the men living in infertile marriages.(ABSTRACT TRUNCATED AT 250 WORDS)

Cell Nucleus↗

The human sperm nucleus takes up zinc at ejaculation.

Ejaculated and vasal sperm were obtained from men referred for vasectomy, and sperm nuclear elements were determined by X-ray microanalysis. Sperm head zinc concentrations, expressed as the ratio Zinc to Sulphur, were significantly higher in ejaculated than in vasal sperm. A physiological sperm nuclear zinc uptake is discussed in relation to sperm chromatin decondensation.

Adult↗

Loss of an intrinsic capacity for human sperm chromatin decondensation.

Chromatin decondensation of human ejaculated spermatozoa was studied in vitro, at various points of time after ejaculation, by sperm exposure to the detergent sodium dodecyl sulphate (SDS) containing zinc chelating EDTA. Within 5 min after ejaculation EDTA revealed a capacity for decondensation in 90% of the spermatozoa. This sperm capacity decreased rapidly upon storage. The results support the concept that the capacity to decondense is a normal property of freshly ejaculated spermatozoa and that this property may be rapidly lost. The loss is most probably due to an inability of thiol groups to take part in a thiol-disulphide exchange in the sperm chromatin. A loss of functional thiols may hinder a capacity for chromatin decondensation inherent to the spermatozoon. A loss of thiols due to oxidation, that is, surplus S-S bridge formation, may also delay hypothetical extrinsic S-S cleaving factors in the ooplasm. In either case, the complete and non-delayed sperm chromatin decondensation in the ovum may be hindered. This may result in the abnormal embryonic development observed in ova fertilized with aged spermatozoa.

Chromatin↗

Zinc preserves an inherent capacity for human sperm chromatin decondensation.

The effect of zinc on the nuclear chromatin decondensation ability of human, ejaculated spermatozoa was studied by exposing washed spermatozoa to the detergent sodium dodecyl sulphate (SDS) before and after sperm storage. Treatment with EDTA increased the proportion of decondensing spermatozoa before storage. Zinc supplementation before storage reversibly inhibited spontaneous decondensation as well as EDTA-enhanced decondensation. Treatment with EDTA before storage decreased the proportion of spermatozoa decondensing after storage. Zinc supplementation during storage reduced the decrease in the proportion of spermatozoa decondensing after storage. Two effects of zinc were observed: one immediate effect (reversible inhibition of the decondensation) and one long-term effect (protection of the intrinsic capacity for decondensation during storage). Both effects may be explained by a zinc-thiol interaction in the chromatin. Spermatozoal zinc is suggested to protect an inherent capacity for decondensation, thereby helping to extend the functional life-span of the ejaculated spermatozoon.

Chromatin↗

Nuclear zinc in human epididymal and ejaculated spermatozoa.

Sperm nuclear zinc content (expressed as zinc/phosphorus and zinc/sulphur ratios) was determined with X-ray microanalysis in individual, air-dried, epididymal spermatozoa from elderly men, and in ejaculated spermatozoa from healthy donors. Ejaculated sperm nuclei contained (also after treatment with sodium dodecyl sulphate) more zinc than epididymal spermatozoa. The results indicate that the human spermatozoon accumulates zinc from the prostatic fluid upon ejaculation.

Adult↗

Removal of zinc from subcellular regions of human spermatozoa by EDTA treatment studied by X-ray microanalysis.

The distribution of zinc in the head, neck and mid-piece of human ejaculated spermatozoa was investigated with energy-dispersive X-ray microanalysis. EDTA treatment within 1 h after ejaculation caused removal of 80-90% of the zinc in these regions. Storage for 24 h in own seminal plasma did not alter sperm zinc content. However, these aged spermatozoa only lost 35% of their zinc content on EDTA treatment. The stronger binding of zinc, occurring upon storage in seminal plasma, developed in all 3 parts of the cell investigated. These results are discussed in the light of the role of zinc in nuclear chromatin decondensation ability and sperm head-tail connection.

Edetic Acid↗