Current practices of commercial cryobanks in screening prospective donors for genetic disease and reproductive risk.

OBJECTIVE: To determine how the screening practices of commercial semen banks vary from published guidelines, which factors influence cryobanks to exclude prospective semen donors for genetic reasons, and the current role of clinical geneticists/genetic counselors in evaluating prospective semen donors. DESIGN: The genetic screening of prospective donors by commercial semen banks was evaluated using written questionnaires completed by bank directors. Responses were analyzed to determine exclusion criteria, adherence to published guidelines, and contribution of genetic professionals. SETTING AND PARTICIPANTS: Semen banks were selected on the basis of membership in the American Association of Tissue Banks and commercial use of semen for artificial insemination by donor. MAIN OUTCOME MEASURE: Semen bank practices as reported by commercial semen bank directors. RESULTS: Of 37 eligible banks, 16 responded. All screen prospective donors by medical/family history and physical examination, 94% have upper age limits; 63% examine for minor physical defects; 56% routinely karyotype; 81% screen men of ethnic groups at risk for Tay Sachs disease, sickle cell disease and thalassemia; 19% screen all donors; 25% screen all donors for cystic fibrosis and 50% only screen if family history positive. Donor rejection was based on three criteria: mode of inheritance of familial disorder, severity of disease, and availability of carrier/confirmatory testing of donor genotype. Ten of 16 banks have no genetic professional on staff. CONCLUSION: Commercial semen banks primarily rely on family history as the major exclusion criterion in genetic screening of donors. Considerable differences exist among semen bank practices in accordance with guidelines published by national agencies. Genetic professionals have a minimal effect overall on evaluation of semen donors.

Treatment of asthma by a controlled-release theophylline tablet formulation: a review of the North American experience with nocturnal dosing.

As many as 80 percent of asthmatics experience nighttime or early-morning episodes, which are difficult to treat and potentially fatal. The greater-than-normal amplitude of circadian airflow variation in many asthmatics contributes heavily to the genesis of the early 'morning dip'. Beta-agonists and corticosteroids are of limited usefulness in nocturnal asthma, and slow-release theophylline drugs, while potentially effective, vary in 24-hr blood profile and hence their influence on nocturnal episodes. Traditional 12-hr 'symmetric' theophylline regimens, instead of meeting increased nocturnal demands, may actually produce lower night- than daytime blood levels. On the other hand, appropriately timed administration of a once-daily theophylline drug might provide maximum blood levels when needed and help stabilize 24-hr airflow. Accumulated data, summarized in this review, demonstrate the chronotherapeutic potential of single-daily evening doses of a controlled-release theophylline preparation (Uniphyl 400-mg tablets) in nocturnal and early morning asthma. Nighttime blood concentrations with this regimen were higher than were those with Theo-Dur tablets, B.I.D., in the same total daily doses, or with once-daily morning Uniphyl administration. In fed and fasted subjects, evening administration of Uniphyl 400-mg tablets was well tolerated and did not lead to 'dose dumping.' Clinically, this treatment demonstrated advantages over B.I.D. theophylline, over single-daily morning regimens, and over prior theophylline therapy. Advantages of the evening regimen included better early-morning airflow (without significant decline later in the day), more effective symptom control, better patient acceptance, fewer night awakenings, and the obvious convenience of once-daily dosing. In addition, lung function showed greater stability, throughout the day, with once-daily evening therapy than with traditional 12 hr dosing. Uniphyl 400-mg tablets may be administered once daily to provide maximum blood levels at the time of peak bronchoconstriction, whether at night or during the day.

Induction of mouse brain ornithine decarboxylase by 12-O-tetradecanoylphorbol-13-acetate is independent of TPA receptor concentration.

Ornithine decarboxylase (ODC, E.C. 4.1.1.17) activity was measured in a 35,000 X g brain supernatant fraction, prepared 5 h after intracisternal injection of 12-O-tetradecanoylphorbol-13-acetate (TPA) into developing mouse brain. TPA-dependent induction of ODC activity was maximal on days 5 and 9 postnatally while on day 7, the developmental (endogenous) level of ODC in brain was high and, concurrently, the ability of TPA to induce ODC was reduced. Both TPA-dependent and developmental increases in mouse brain ODC activity were significantly reduced by intracisternal injection of retinoic acid (RA). The efficacy of TPA in elevating ODC activity at postnatal ages 1-220 days-old was independent of both soluble-and particulate-associated TPA receptor concentration. These observations suggest that although TPA receptor activation may be an obligatory event in ODC induction, TPA receptor activation and its concentration per se, are not sufficient determinants for ODC induction and tumorigenesis. Furthermore, the endogenous mechanism of ODC induction is distinct from that of the TPA-dependent increase in ODC enzyme activity.

Effects of amino acid treatments on 12-O-tetradecanoylphorbol-13-acetate-induced ornithine decarboxylase activity in mouse epidermis in vivo and in vitro.

We have compared the effects of several amino acid treatments on the induction of ornithine decarboxylase activity and the accumulation of putrescine, spermidine, and spermine by 12-O-tetradecanoylphorbol-13-acetate (TPA) in mouse epidermis in vivo and in vitro. Incubation of isolated epidermal cells with mM concentrations of glycine, asparagine, glutamic acid, canavanine, arginine, and/or lysine inhibited dramatically the induction of ornithine decarboxylase activity by the tumor promoter. These remarkable inhibitory effects were concentration-dependent and additive. Arginine and its analog, canavanine, inhibited to the same degree TPA-induced ornithine decarboxylase activity, and potentiated to the same extent the inhibitory effects of glutamic acid, asparagine, and glycine on this enzyme. However, the inhibitory effects of arginine and canavanine were not additive. Similar alterations of tumor promoter-induced epidermal ornithine decarboxylase activity were observed in vivo when 62.5 mumol of the amino acids were injected i.p. 2 h before the topical application of 8.5 nmol of TPA to mouse skin. The results suggest the possibility that treatments with glycine, asparagine, glutamic acid, and arginine, the amino acids that were the most effective in inhibiting the tumor promoter-induced accumulation of polyamines in vivo, may reduce the tumor-promoting ability of TPA.

Effects of cell surface receptor-altering agents on the binding and biological activity of 12-O-tetradecanoylphorbol-13-acetate in isolated epidermal cells.

Isolated epidermal cells were incubated with a variety of compounds known to interfere with or alter the ultrastructure of cell surface receptors, and the ability of 12-O-tetradecanoyl-phorbol-13-acetate (TPA) to bind to these cells and induce epidermal ornithine decarboxylase (ODC) activity was investigated. The alpha- and beta-adrenergic antagonists, phentolamine and propranolol, and the cholinergic antagonist, atropine, which competed effectively for the binding receptors of [3H]dihydro-alpha-ergocryptine, [3H]dihydroalprenolol, and [14C]acetylcholine, did not inhibit the induction of ODC activity by TPA or the specific binding of [3H]TPA to the cells. Neuraminidase treatments caused a time- and dose-related release of sialic acid from the cells and enhanced the stimulatory effect of cholera toxin on basal and TPA-induced ODC activities as much as the monosialoganglioside GM1. Neuraminidase and the other membrane-altering agents, fucosidase, galactosidase, galactose oxidase, phospholipases A2 and C, and NaIO4, were used alone and/or in various combinations in our studies. All treatments tested inhibited the specific binding of several 125I-labeled hormones and epidermal growth factor to the cells. In contrast, none of these treatments was able, in the same cell system, to affect either the binding or the biological activity of TPA. Therefore, these results suggest that the primary interaction of TPA at the plasma membrane level as well as its biological effect in the intact cell do not proceed through adrenergic or cholinergic receptors and do not require the integrity of the cell surface glycoconjugates and phospholipids. In addition, the inhibitory effect of retinoic acid on TPA-induced ODC activity remained unaffected by some of the above treatments, suggesting that retinoic acid is unlikely to interfere with TPA interactions at the plasma membrane level.

Induction of mouse epidermal ornithine decarboxylase activity and skin tumors by 7,12-dimethylben.

Application of a single large dose (3.6 micromol) or smaller weekly repeated doses (0.2 micromol) of 7,12-dimethylbenz[a]anthracene (DMBA) to the skin of CD-1 mice led to a 20 to 50-fold increase in epidermal ornithine decarboxylase (ODC) (EC 4.1.1.17) activity as well as tumor formation. Retinoic acid (0.17-68 nmol), a potent inhibitor of both the induction of ODC activity and tumor formation by the tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA), failed to inhibit both the induction of ODC activity and tumor formation by DMBA. In contrast, 7,8-benzoflavone (367 nmol), which did not inhibit the induction of ODC activity by TPA, effectively inhibited the induction of ODC activity as well as the formation of skin tumors caused by DMBA. These results indicate that (a) the mechanism of the induction of ODC activity and tumor formation by a complete carcinogen appears to be different from that of the tumor promoter TPA, (b) DMBA-induced ODC activity may be an important component of the mechanism of DMBA carcinogenesis, and (c) the protective effect of retinoic acid on skin carcinogenesis is not universal; it inhibits skin tumor formation by some agents and not by others.