Z. T. Homonnai

Bio: Z. T. Homonnai is an academic researcher. The author has contributed to research in topics: Sperm & Transferrin. The author has an hindex of 2, co-authored 2 publications receiving 28 citations.

Transferrin in seminal plasma and in serum of men: its correlation with sperm quality and hormonal status

Abstract: Transferrin concentrations in the seminal plasma and in serum were measured and correlated with sperm quality (concentration, motility and morphology) and hormonal status (FSH, LH and testosterone) of 75 men aged from 21 to 46 years. A significant positive correlation was found between the seminal plasma concentration of transferrin and the sperm concentration (r = 0.69, P less than 0.0001) and motility (r = 0.39, P less than 0.0001). No other correlations were found. These data confirm that seminal plasma levels of transferrin can be used as a reliable index of sperm quality, and possibly as a Sertoli cell marker.

Andrology: The use of hemizona assay in the evaluation of the optimal sperm preparation technique

Abstract: The objective of the study was to evaluate the benefit of different sperm preparation methods by using the hemizona assay. A total of 58 men admitted to the male infertility clinic for evaluation were tested by routine semen analysis and hemizona assay. Five different techniques (swim-up, TEST-yolk buffer, Percoll, pentoxifylline and progesterone) were used for preparation of sperm suspensions. The effect of these treatments on the sperm-binding capacity using the hemizona assay was assessed. The routine swim-up preparation was used as the reference method. Of the four preparation methods, only the TEST-yolk buffer and pentoxifylline exhibited an overall statistically significant improvement in sperm-binding capacity in comparison with the swim-up preparation method (P = 0.01 and 0.001 respectively). Following preparation with Percoll and progesterone there was no change in the mean value of binding capacity, compared with swim-up. However, examination of the effect of the four treatments on each specimen individually yielded a diversity in the response, e.g. having the capability to enhance, damage or be ineffective in sperm binding capacity. The results support the conclusion that in-vitro sperm preparation methods can affect sperm binding to the zona pellucida. Since there is a diversity in the response of sperm samples to different treatments, the hemizona assay can be used in selecting the optimal sperm preparation method prior to its use for assisted reproductive techniques. This is advocated mainly for the 'male factor' group.

Semen preparation techniques for intrauterine insemination

Abstract: Background Semen preparation techniques for assisted reproduction, including intrauterine insemination (IUI), were developed to separate the motile morphological normal spermatozoa. Leucocytes, bacteria and dead spermatozoa produce oxygen radicals that negatively influence the ability to fertilize the egg. The yield of as many motile, morphologically normal spermatozoa as possible might influence treatment choices and therefore outcomes. Objectives To compare the effectiveness of gradient, swim-up, or wash and centrifugation semen preparation techniques on clinical outcome in subfertile couples undergoing intrauterine insemination (IUI). Search strategy We searched the Menstrual Disorders and Subfertility Group Trials Register (3 January 2007), Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2007, Issue 2), MEDLINE (1966 to January 2007), EMBASE (1980 to January 2007), Science Direct Database (1966 to January 2007), National Research Register (2000 to 2007), Biological Abstracts (2000 to January 2007), CINAHL (1982 to October 2006) and reference lists of relevant articles. We also contacted experts and authors in the field. Selection criteria Parallel randomized controlled trials (RCTs) comparing the efficacy of semen preparation techniques used for subfertile couples undergoing IUI in terms of clinical outcome were included. Data collection and analysis Two reviewer authors independently assessed trial quality and extracted data. Study authors were contacted for additional information. Main results Five RCTs, including 262 couples in total, were included in the meta-analysis (Dodson 1998; Grigoriou 2005; Posada 2005; Soliman 2005; Xu 2000). Xu compared the three techniques; Soliman compared a gradient technique versus a wash technique; Dodson and Posada compared a gradient technique versus a swim-up technique; whereas Grigoriou compared swim-up versus a wash technique. No trials reported the primary outcome of live birth. There was no evidence of a difference between pregnancy rates (PR) for swim-up versus a gradient or wash and centrifugation technique (Peto OR 1.57, 95% CI 0.74 to 3.32; Peto OR 0.41, 95% CI 0.15 to 1.10, respectively); nor in the two studies comparing a gradient technique versus wash and centrifugation (Peto OR 1.76, 95% CI 0.57 to 5.44). There was no evidence of a difference in them is carriage rate (MR) in two studies comparing swim- up versus a gradient technique (Peto OR 0.13, 95% CI 0.01 to 1.33). Authors' conclusions There is insufficient evidence to recommend any specific preparation technique. Large high quality randomised controlled trials, comparing the effectiveness of a gradient and/or a swim-up and/or wash and centrifugation technique on clinical outcome are lacking. Further randomised trials are warranted.

The Testicular Iron Shuttle: A “Nurse” Function of the Sertoli Cells

Abstract: The techniques of cell culture and molecular biology first revealed that Sertoli cells synthesize transferrin. Accumulated biological information led to a plausible model for the role of testicular transferrin in an iron shuttle system designed to transport ferric ions around the cellular tight junctions to the germ cells inside the blood-testis barrier. Experiments done in culture and in vivo have supported many aspects of this model. A mutant mouse model that lacks the ability to synthesize transferrin is defective in spermatogenesis and may help to delineate the nature of the iron requirement by germ cells. The levels of seminal transferrin, possibly of Sertoli cell origin, are proportional to sperm production in humans and cattle and may be an effective indicator of Sertoli cell function. The testicular iron shuttle thus represents an important "nurse cell" function of the Sertoli cells.

Biological and clinical aspects of soluble transferrin receptor

Abstract: Soluble transferrin receptor (sTfR), one of the main regulators of cellular iron homeostasis, is the truncated form of the tissue receptor that is encoded by the human TfR gene (chromosome 3). Serum sTfR levels are determined to detect iron deficiency (ID) in inflammatory states and in anemia of chronic disease (ACD) and to monitor the efficiency of erythropoietin (EPO) treatment. The levels of sTfR reflect the receptor density on cells (tissue iron status) and the number of cells with receptors (erythropoietic activity). Currently assays for the measurements of sTfR are standardized using different reference materials, give different results, and have different reference ranges. The recent development of a lyophilized preparation of recombinant soluble transferrin receptor (rsTfR) as a World Health Organization (WHO) reference reagent should help in the standardization of sTfR immunoassays. This article reviews the general characteristics of (s)TfR, the assays for sTfR, biological confounders in the assays, and the clinical applications for measuring sTfR

Sperm and seminal fluid proteomes of the field cricket Teleogryllus oceanicus: identification of novel proteins transferred to females at mating

Abstract: Reproductive proteins are amongst the most evolutionarily divergent proteins known, and research on genetically well-characterized species suggests that postcopulatory sexual selection might be important in their evolution; however, we lack the taxonomic breadth of information on reproductive proteins that is required to determine the general importance of sexual selection for their evolution. We used transcriptome sequencing and proteomics to characterize the sperm and seminal fluid proteins of a cricket, Teleogryllus oceanicus, that has been widely used in the study of postcopulatory sexual selection. We identified 57 proteins from the sperm of these crickets. Many of these had predicted function in glycolysis and metabolism, or were structural, and had sequence similarity to sperm proteins found across taxa ranging from flies to humans. We identified 21 seminal fluid proteins, some of which resemble those found to be involved in postmating changes to female reproduction in other species. Some 27% of sperm proteins and 48% of seminal fluid proteins were of unknown function. The characterization of seminal fluid proteins in this species will allow us to explore their adaptive significance, and to contribute comparative data that will facilitate a general appreciation of the evolution of reproductive proteins within and among animal taxa.