Molecular andrology: advances in the new millennium.
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Genetics, Medical↗
Biomedical subjects
B Hafez
Publications and source records attributed to B Hafez.
Stress/aging: endocrine profiles/reproductive dysfunction in men.
Extensive investigations have been carried out on the biology/physiology of stress [13, 18, 20, 25, 35, 48, 49, 53, 55], pathophysiology of aging [41], sexual dysfunction [7, 27] and adrenal insufficiency [4, 31].
Aging↗
Initiation of the reproductive cycle.
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Abortion, Induced↗
Recent advances in andrology research: physiopathology and clinical application to fertility and infertility.
Sperm maturation depends on androgen and is mediated by several unidentified epididymal factors: glycoproteins and metabolites affecting acrosomal stability and fertilizing potential of capacitated sperm. Several genes encoding human epididymis-specific proteins have been described. One of the cloned epididymal cDNA encodes a polypeptide designated as HE4 with an estimated molecular mass of 10,000. Leydig cells are rich in lipid droplets and display epithelioid features. These cells have a cord-like arrangement; the cords are formed by one or two closely apposed cells. In between these cells, labyrinthine or canalicular-like spaces are opened in wide perivascular spaces that improve cell secretion of hormones and facilitate their transport into the blood, as well as the traffic of fluids and metabolites. Coagulation and liquefaction in human semen plays an important role in the capacitation of semen. The liquefaction of semen is retarded by the powerful synthetic inhibitors of 6-amidino-2-naphtyl-p-guanidinobenzoate dimethansulfonate.
Animals↗
Recent advances in clinical/molecular andrology.
During the last decade there were extensive investigations in clinical and molecular andrology with emphasis on assisted reproduction, micromanipulation techniques of gametes, sperm/egg interaction, male contraception, diabetes mellitus, varicocele, andropause versus menopause, sexual dysfunction, associated hypertension/stress, prostatic carcinoma and molecular parameters of male reproduction. Sperm hyperactivation is a required step in capacitation sequence. Sperm motility is measured by videotape to evaluate the Straight Line Velocity (microm/s) (VSLI). Fertilization/embryonic development results from single sperm transfer (S-MIST) and multiple sperm transfer. Fertilization/embryo development is achieved by injection of immotile sperm into the perivitelline space. To assess sperm viability, a supravital stain suitable for use in combination with immunofluorescent assay, Hoeschst 33258, is used. The dye fluoresces with an intense blue when bound to DNA. To assess sperm plasma membrane integrity, a hypo-osmotic swelling test (HOST) is performed, using fluoresceinated D-mannose enriched albumin (FITC-DMA). The ability of sperm to swell under hypo-osmotic conditions indicates an intact membrane. A human protein, C-peptide, thought to be a useless byproduct of insulin may protect against devastating heart and nerve damage that diabetes causes. Human diabetics may benefit from the substance. Over 15 million Americans have diabetes, in which blood sugar levels rise out of control. There are two types of diabetics: Type I diabetics produce no insulin, the hormone that regulates blood sugar. Type II diabetics are unable to use their insulin properly. Diabetics are at great risk of heart disease and nerve damage, as arteries throughout the body leak and nerve-cell impulses fail. C-peptide is a byproduct of insulin production; it can be produced by the body or synthetically. Production of this protein is not induced by insulin, so diabetics who take insulin do not get C-peptide with it. Varicocele occurs unilaterally on the left side in 78% to 93% of men. Typically the presence of a varicocele is associated with an abnormal semen analysis (sperm density and morphology) and a decreased testicular volume on the affected side. Impaired sperm motility occurs in 89.5% of all varicocele patients. Varicocele ligation improves semen parameters in two thirds of patients. A few studies on andropause included sexual dysfunction, hormonal changes, medical/psychological correlates of impotence, ostenopenia/osteoporosis and bone loss; indices of bone remodeling, testosterone supplementation, androgen, negative feedback and hypothalamo-pituitary-testicular axis. Prostatic cancer is the second leading cause of cancer death for men between the ages of 60 and 80. Early detection involves a simple blood test for prostate specific antigen (PSA). Regular screening and early detection are essential. This is an important test because a high antigen count can be the only symptom. Since no screening is 100% accurate, physicians recommend both a PSA blood test and a physical examination. Although heredity plays a major role in whether a man will develop prostate cancer, men who lead healthy lives can dramatically reduce their chances of cancer: low-fat diet, eating plenty of fruits and vegetables and not smoking. Recent advances in molecular andrology include peptide hormone binding proteins; gonadotropin-releasing hormone (GnRH) agonists/antagonists analog; gonadotropins/their receptors; growth factors/reproduction; peptides as intratesticular regulators; molecular cloning of reproductive proteins/peptides. Gene cloning is applied for characterization/expression of genes coding. The interaction of gp120 with CD4 receptor plays a role in syncytium formation, apoptosis and CD4 cell deletion in human immunodeficiency virus (HIV) infection. The recombinant V3 peptide of fragment 307-330 of HIV-1 can induce sperm head agglutination. The generation process of react
Contraception↗
Reproductive parameters of male dromedary and bactrian camels.
Functional anatomy of male reproductive organs and reproductive physiology of dromedary and bactrian camels are quite similar except for some differences in the seasonal pattern of reproductive events: left testes bigger than right; scrotum not pendulous; vas deferens very convoluted with 2 mm diameter; prostate divided into 2 parts by septum, with many ducts; bulbourethral (Cowper's) glands well developed and seminal vesicle absent; fibroelastic penis has "prescrotal" sigmoid flexure and the glans resembles crochet needle; triangular-shaped prepuce directed posteriorly to open to the rear, and can move cranially or caudally during erection or urination, respectively; semen ejaculate, 1-12 mL in volume with little gelatinous material, coagulates and liquifies within minutes; total sperm/ejaculate 6 x 10(9) sperm/mL; semen contains PGE1, PGE(2x,LH), estradiol progesterone/other metabolites; semen collected by AV used for bulls with long copulation time; ovulation induced 36-48 h after mating or insemination; sperm of a short life of 1-6 h at 0.4 degrees C, is prolonged in presence of mucopolysaccharide gel; fresh semen inseminated. Topics of future research on endocrinology of reproduction, gonadal physiology, semen biology assisted reproductive technology, and gene transfer to germ cells of camels are outlined. The prevention and control of STD is an important component of camel stud management to improve reproductive performance in this species.
Animals↗
Andropause: endocrinology, erectile dysfunction, and prostate pathophysiology.
This review summarizes major biological aspects of andrology of andropause, deficiency in androgens/growth hormones, and molecular parameters; erectile dysfunction (ED), the use of malleable, mechanical, inflatable devices as well as the application of Viagra (Sildenafil), alprotadil (Caverject), Yohimbine, and other drugs not yet approved by FDA, such as Papaverine, phentolamine (Vasomax), and apormorphine (Uprima); osteopenia/osteoporosis: testosterone/osteoporesis; supplementation during andropause: administration of andiogens, possible risk factors of androgens, calcium supplement and muscle mass; prostate pathophysiology: consequences of prostatectomy, prostate cancer, benign prostatic hyperplasia (BPH), hormone-dependent cancers; bladder and urethral dysfunction: neurological parameter, urodynamics technology; models on aging in male animals: comparative physiology of prostate of laboratory animals/farm animals; future research: functional anatomy of male reproductive organs, pharmacokinetics of osteoporosis, endocrinology/neuroendocrinology/chromosome anomalies supplementation during andropause, experimental animal models and future multicenter multidisciplinary research.
Androgens↗
Mammalian fertilization, IVF, ICSI: physiological/molecular parameters, clinical application.
Fertilization is associated with several phenomena: rearrangement of euplastic cytoskeleton, intra-cellular communication, cellular polarity, and the release of a variety of complex systems. Several criteria are used to score fertilization. On the day after fertilization, oocytes are cleaned of cumulus and examined for presence of 2 pronuclei and any possible cytological anomalies. Function tests to evaluate fertilization include SPA, ZBA, SCSA, AAA acrosome reaction and fluorescent probes. Fertilization failure, silent polyspermy, aster arrest, mitotic arrest, aster growth defect, or immuno-logical mechanisms cause infertility. Sperm-induced oocyte activation may be due to ligand-recep-tor-mediated interaction or a soluble sperm-derived factor that enters the oocyte at the time of fusion. Any abnormalities in transcription, translation, or any other significant molecular process responsible for producing the oocyte-activating ligand/effector molecule during spermatogenesis and/or spermatogenesis will ultimately cause fertilization failure. The centrosome is paternally derived. During the time course of fertilization the sperm centrosome is orchestrating producer mobilization, syngamy and, ultimately, early cleavage. Vesicle-associated membrane protein(VAMP) is typically lost at cell surface during sperm penetration. Understanding cytoskeletal motility during fertilization requires sophisticated digital imaging including conventional epifluorescence microscopy, laser scanning confocal microscopy and time lapse video microscopy. Clinical application of the recent finding is discussed with emphasis on timing of coitus or insemination, to coincide with time of monitored ovulation. Future research directions are outlined.
Animals↗