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Biomedical subjects

M Schrader

Publications and source records attributed to M Schrader.

149 records · Page 9Linked to original sources
PubMedDate not supplied

The impact of chemotherapy on male fertility: a survey of the biologic basis and clinical aspects.

The introduction of cisplatin-based polychemotherapy has led to cure rates of up to 90% for the most frequent malignant diseases seen in young men. In view of these high cure rates, increasing clinical importance is now being attached to chemotherapy-induced fertility disorders. Comparative studies examining the impact of cytotoxic chemotherapy on gametogenesis demonstrate significant cytostatic- and dose-specific differences. The extensive literature on possible teratogenic effects of chemotherapy provides no evidence suggesting that offspring of patients with a history of chemotherapy have an increased risk of malformations. However, these studies, the scope and follow-up of which may still be inadequate, have failed to eliminate the fear of such risk. Hormonal protection from chemotherapy-induced testicular damage has thus far succeeded only in animal models pretreated by application of gonadotropin-releasing hormone agonists combined with nonsteroidal antiandrogens or testosterone plus 17 beta-estradiol. The same holds true for hormone therapy aimed at stimulating the recovery of spermatogenesis after chemotherapy-induced testicular damage. Cryopreservation of germ cells can be suggested to patients undergoing cytostatic therapy. In some cases, testicular extraction of spermatozoa can also be offered as a novel approach.

Adult↗
PubMedDate not supplied

Germ cell transplantation: a review and progress report on ICSI from spermatozoa generated in xenogeneic testes.

Results from the transplantation of donor male germ cells into xenogeneic recipient seminiferous tubules indicate that donor spermatogonia are capable of differentiating to form spermatozoa morphologically characteristic of the donor species. Germ cell transplantation procedures combined with developments in freezing, culturing or enriching germ cell populations have applications of paramount importance in medicine, basic sciences and animal reproduction. Additionally, these techniques can serve as an alternative approach for gonadal protection and fertility preservation in patients with cancer. This article is a chronological critical review of the technological advances that followed the initial successful transplantation of mouse germ cells into recipient mice. Furthermore, the factors responsible for the immunological privilege properties of the testis and the parameters influencing the potential of mammalian germ cells to undergo mitosis and meiosis within a xenogeneic testis are described. Finally, the role of human germ cell transplantation procedures in the therapeutic management of non-obstructive azoospermia is discussed.

Animals↗
PubMedDate not supplied

Gadolinium cryptelates as MR contrast agents.

Gadolinium cryptelates are complexes of a lanthanide metal ion with amino acids of macrocyclic polyamines. These compounds are water soluble and possess reduced relaxation properties similar to Gd diethylene triamine pentaacetic acid (DTPA). Three Gd cryptelates (Gd NOTA, DOTA, TETA) were evaluated. Gadolinium DOTA is the most stable Gd complex with a dissociation constant of 10(-28) and appears to have a greater serum stability than Gd DTPA. Gadolinium NOTA and Gd TETA have lower dissociation constants than Gd DTPA at 10(-17) and 10(-19). Gadolinium DOTA has tissue distribution properties similar to Gd DTPA, is rapidly excreted by the kidneys, and provides a high degree of contrast enhancement on magnetic resonance (MR) images, both systemically and within the CNS. Hence, Gd DOTA is an alternative water-soluble MR contrast agent to Gd DTPA.

Animals↗
PubMedDate not supplied

MR imaging of the postoperative lumbar spine: assessment with gadopentetate dimeglumine.

This study defines the accuracy of gadopentetate-dimeglumine-enhanced MR imaging in patients with failed back surgery syndrome by comparing the imaging studies with surgical findings in a large patient population. From June 1988 to March 1989, 193 postoperative patients had MR imaging of the lumbar spine both with and without contrast administration. Of this group, 27 had repeat surgery at 31 levels: these patients comprise the study group. Postcontrast MR diagnoses were as follows: scar only (n = 4), disk only (n = 13), scar and disk (n = 9), and no aberrant epidural tissue (n = 5). Surgical diagnoses differed from the MR diagnoses in two patients at two levels. In one patient, disk was diagnosed on MR while osteophyte was present at surgery. In the other patient, scar only was diagnosed by MR but disk and scar were present at surgery. These data, when combined with the authors' previous experience, give pre- and postcontrast MR a 96% accuracy in differentiating scar from disk in 44 patients at 50 reoperated levels. For patients 6 or more weeks past surgery, sagittal and axial T1-weighted MR imaging before and after administration of gadopentetate dimeglumine is an effective method of evaluating the postoperative lumbar spine.

Adult↗