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Lorna K. Jost

Bio: Lorna K. Jost is an academic researcher from South Dakota State University. The author has contributed to research in topics: Sperm & Spermatogenesis. The author has an hindex of 32, co-authored 42 publications receiving 6132 citations.

Papers
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Journal ArticleDOI
TL;DR: Based on logistic regression, spermatozoa with denatured DNA (cells outside the main population, COMP alpha t) were the best predictor for whether a couple would not achieve pregnancy.
Abstract: The sperm chromatin structure assay (SCSA) was used to measure over 500 human semen samples from two independent studies: Study I, 402 samples from 165 presumably fertile couples wishing to achieve pregnancy over 12 menstrual cycles; Study II, samples from 115 patients seeking fertility counselling. The SCSA measures susceptibility to DNA denaturation in situ in spermatozoa exposed to acid for 30 s, followed by acridine orange staining. SCSA data from the male partners of 73 couples (group 1) achieving pregnancy during months 1‐3 of Study I were used as the standard of ‘sperm chromatin compatible with high fertility’ and were significantly different from those of 40 couples (group 3) achieving pregnancy in months 4‐12 (P < 0.01) and those of male partners of 31 couples (group 4) not achieving pregnancy (P < 0.001). Group 2 contained couples who had a miscarriage. SCSA values for Study II were almost twice that of the Study I fertility standards. Within-couple repeatability tended to be less for group 3 than for groups 1, 2 or 4. Based on logistic regression, spermatozoa with denatured DNA (cells outside the main population, COMPa t) were the best predictor for whether a couple would not achieve pregnancy. Some 84% of males in group 1 had COMPat <15%, while no couples achieved pregnancy in group 1 with ‡30% COMPat, a threshold level considered not compatible with good fertility. Using selected cut-off values for chromatin integrity, the SCSA data predicted seven of 18 miscarriages (39%).

1,065 citations

Journal ArticleDOI
TL;DR: The predictive value of sperm chromatin integrity for pregnancy outcome following in-vitro fertilization and intracytoplasmic sperm injection was studied and the SCSA parameters are independent of conventional semen parameters, allowing physicians to identify male patients for whom IVF and ICSI will be unlikely to result in pregnancy initiation.
Abstract: The predictive value of sperm chromatin integrity for pregnancy outcome following in-vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) was studied in 24 men attending a university-based assisted reproductive techniques laboratory using the flow cytometric sperm chromatin structure assay (SCSA). The SCSA is a measure of the susceptibility of sperm DNA to low pH-induced denaturation in situ. The mean percentage of spermatozoa in the neat sample demonstrating DNA denaturation was significantly lower in the seven men that initiated a pregnancy (15.4 +/- 4.6, P = 0.01) than in the 14 men who did not initiate a pregnancy (31.1 +/- 3.2). No pregnancies resulted if > or =27% of the spermatozoa in the neat semen sample showed DNA denaturation. These data demonstrate that SCSA parameters are independent of conventional semen parameters. Furthermore, the SCSA may allow physicians to identify male patients for whom IVF and ICSI will be unlikely to result in pregnancy initiation.

469 citations

Journal ArticleDOI
01 Jan 2000
TL;DR: The Sperm Chromatin Structure Assay (SCSA) as discussed by the authors is a tool for measuring clinically important properties of sperm nuclear chromatin integrity, which is used to assess male sperm DNA integrity as related to fertility potential and embryo development.
Abstract: The Sperm Chromatin Structure Assay (SCSA) serves as a tool for measuring clinically important properties of sperm nuclear chromatin integrity. The assay utilizes the metachromatic features of Acridine Orange (AO), a DNA probe, and the principles of flow cytometry (FCM). SCSA data are not well correlated with classical sperm quality parameters and have been solidly shown to predict sub/infertility. This assay is ideally suited to human and animal fertility clinics to assess male sperm DNA integrity as related to fertility potential and embryo development as well as effects of reproductive toxicants. A detailed description of the SCSA follows.

407 citations

01 Jan 2000
TL;DR: The Sperm Chromatin Structure Assay serves as a tool for measuring clinically important properties of sperm nuclear chromatin integrity and is ideally suited to human and animal fertility clinics to assess male sperm DNA integrity as related to fertility potential and embryo development as well as effects of reproductive toxicants.
Abstract: The Sperm Chromatin Structure Assay (SCSA) serves as a tool for measuring clinically important properties of sperm nuclear chromatin integrity. The assay utilizes the metachromatic features of Acridine Orange (AO), a DNA probe, and the principles of flow cytometry (FCM). SCSA data are not well correlated with classical sperm quality parameters and have been solidly shown to predict sub/infertility. This assay is ideally suited to human and animal fertility clinics to assess male sperm DNA integrity as related to fertility potential and embryo development as well as effects of reproductive toxicants. A detailed description of the SCSA follows.

401 citations


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Journal ArticleDOI
TL;DR: The present review describes several methods to characterize and differentiate between two different mechanisms of cell death, apoptosis and necrosis, applied to studies of apoptosis triggered in the human leukemic HL-60 cell line by DNA topoisomerase I or II inhibitors, and in rat thymocytes by either topoisomersase inhibitors or prednisolone.
Abstract: The present review describes several methods to characterize and differentiate between two different mechanisms of cell death, apoptosis and necrosis. Most of these methods were applied to studies of apoptosis triggered in the human leukemic HL-60 cell line by DNA topoisomerase I or II inhibitors, and in rat thymocytes by either topoisomerase inhibitors or prednisolone. In most cases, apoptosis was selective to cells in a particular phase of the cell cycle: only S-phase HL-60 cells and G0 thymocytes were mainly affected. Necrosis was induced by excessively high concentrations of these drugs. The following cell features were found useful to characterize the mode of cell death: a) Activation of an endonuclease in apoptocic cells resulted in extraction of the low molecular weight DNA following cell permeabilization, which, in turn, led to their decreased stainability with DNA-specific fluorochromes. Measurements of DNA content made it possible to identify apoptotic cells and to recognize the cell cycle phase specificity of the apoptotic process. b) Plasma membrane integrity, which is lost in necrotic but not apoptotic cells, was probed by the exclusion of propidium iodide (PI). The combination of PI followed by Hoechst 33342 proved to be an excellent probe to distinguish live, necrotic, early- and late-apoptotic cells. c) Mitochondrial transmembrane potential, assayed by retention of rhodamine 123 was preserved in apoptotic but not necrotic cells. d) The ATP-dependent lysosomal proton pump, tested by the supravital uptake of acridine orange (AO) was also preserved in apoptotic but not necrotic cells. e) Bivariate analysis of cells stained for DNA and protein revealed markedly diminished protein content in apoptotic cells, most likely due to activation of endogenous proteases. Necrotic cells, having leaky membranes, had minimal protein content. f) Staining of RNA allowed for the discrimination of G0 from G1 cells and thus made it possible to reveal that apoptosis was selective to G0 thymocytes. g) The decrease in forward light scatter, paralleled either by no change (HL-60 cells) or an increase (thymocytes) of right angle scatter, were early changes during apoptosis. h) The sensitivity of DNA in situ to denaturation, was increased in apoptotic and necrotic cells. This feature, probed by staining with AO at low pH, provided a sensitive and early assay to discriminate between live, apoptotic and necrotic cells, and to evaluate the cell cycle phase specificity of these processes. i) The in situ nick translation assay employing labeled triphosphonucleotides can be used to reveal DNA strand breaks, to detect the very early stages of apoptosis.(ABSTRACT TRUNCATED AT 400 WORDS)

1,953 citations

Journal ArticleDOI
TL;DR: Evidence for new approaches for improving the performance of cryopreserved semen is offered and factors affecting the proportion of survivors and functional status of survivors are reviewed.

1,383 citations

Journal ArticleDOI
TL;DR: Flow cytometry appears to be the methodology of choice to study various aspects of necrobiology and it is expected that flow cytometry will be the dominant methodology for necro biology.
Abstract: The term cell necrobiology is introduced to comprise the life processes associated with morphological, biochemical, and molecular changes which predispose, precede, and accompany cell death, as well as the consequences and tissue response to cell death. Two alternative modes of cell death can be distinguished, apoptosis and accidental cell death, generally defined as necrosis. The wide interest in necrobiology in many disciplines stems from the realization that apoptosis, whether it occurs physiologically or as a manifestation of a pathological state, is an active mode of cell death and a subject of complex regulatory processes. A possibility exists, therefore, to interact with the regulatory machinery and thereby modulate the cell's propensity to die in response to intrinsic or exogenous signals. Flow cytometry appears to be the methodology of choice to study various aspects of necrobiology. It offers all the advantages of rapid, multiparameter analysis of large populations of individual cells to investigate the biological processes associated with cell death. Numerous methods have been developed to identify apoptotic and necrotic cells and are widely used in various disciplines, in particular in oncology and immunology. The methods based on changes in cell morphology, plasma membrane structure and transport function, function of cell organelles, DNA stability to denaturation, and endonucleolytic DNA degradation are reviewed and their applicability in the research laboratory and in the clinical setting is discussed. Improper use of flow cytometry in analysis of cell death and in data interpretation also is discussed. The most severe errors are due to i) misclassification of nuclear fragments and individual apoptotic bodies as single apoptotic cells, ii) assumption that the apoptotic index represents the rate of cell death, and iii) failure to confirm by microscopy that the cells classified by flow cytometry as apoptotic or necrotic do indeed show morphology consistent with this classification. It is expected that flow cytometry will be the dominant methodology for necrobiology. Cytometry 27:1–20, 1997. © 1997 Wiley-Liss, Inc.

1,146 citations

Journal ArticleDOI
TL;DR: Based on logistic regression, spermatozoa with denatured DNA (cells outside the main population, COMP alpha t) were the best predictor for whether a couple would not achieve pregnancy.
Abstract: The sperm chromatin structure assay (SCSA) was used to measure over 500 human semen samples from two independent studies: Study I, 402 samples from 165 presumably fertile couples wishing to achieve pregnancy over 12 menstrual cycles; Study II, samples from 115 patients seeking fertility counselling. The SCSA measures susceptibility to DNA denaturation in situ in spermatozoa exposed to acid for 30 s, followed by acridine orange staining. SCSA data from the male partners of 73 couples (group 1) achieving pregnancy during months 1‐3 of Study I were used as the standard of ‘sperm chromatin compatible with high fertility’ and were significantly different from those of 40 couples (group 3) achieving pregnancy in months 4‐12 (P < 0.01) and those of male partners of 31 couples (group 4) not achieving pregnancy (P < 0.001). Group 2 contained couples who had a miscarriage. SCSA values for Study II were almost twice that of the Study I fertility standards. Within-couple repeatability tended to be less for group 3 than for groups 1, 2 or 4. Based on logistic regression, spermatozoa with denatured DNA (cells outside the main population, COMPa t) were the best predictor for whether a couple would not achieve pregnancy. Some 84% of males in group 1 had COMPat <15%, while no couples achieved pregnancy in group 1 with ‡30% COMPat, a threshold level considered not compatible with good fertility. Using selected cut-off values for chromatin integrity, the SCSA data predicted seven of 18 miscarriages (39%).

1,065 citations