SPERM method

Padungtod C, Hassold TJ, Millie E, et al. 1999. Sperm aneuploidy among Chinese pesticide factory workers Scoring by the FISH method. Am J Ind Med 36 230-238. 

Contraception is the prevention of pregnancy following sexual intercourse by inhibiting sperm from reaching a mature ovum (i.e., methods that act as barriers or prevent ovulation) or by preventing a fertilized ovum from implanting in the endometrium (i.e., mechanisms that create an unfavorable uterine environment). 

Table 1. Multiple regression equations for the number of sperm inseminated during copulation or ejaculated during masturbation. Also shown are the variables entered but subsequently removed from the equations because P>0.05. The equations are based on the total data sets with missing values for independent variables replaced by means as explained in Materials and Methods. Both equations are a very significant fit to the data (P<0.001) and all variables have P<0.05. However, because of pseudo-replication, the regression equations are a tool rather than ends in themselves...

The current data set contains 20 ejaculates (from 11 different men with 13 different women) which were collected under circumstances other than within a long-term partnership. There were three main situations (see Material and Methods). All were outside of a partnership (and thus qualify as EPCs) and all were situations in which the man would have had every reason, consciously and/or subconsciously, to assume that the woman already contained sperm from another man. Sperm competition theory, therefore, would predict that the male should inseminate an above average number of sperm (Parker 1990). However, neither actual sperm numbers, numbers controlled for hours since last ejaculation, nor numbers controlled for all of the factors in Table 1, supported the prediction (Table 2). On the contrary, males seemed to inseminate fewer sperm into women who were not their established partner. 

The broad field of nucleic acid structure and dynamics has undergone remarkable development during the past decade. Especially in regard to dynamics, modem fluorescence methods have yielded some of the most important advances. This chapter concerns primarily the application of time-resolved fluorescence techniques to study the dynamics of nucleic acid/dye complexes, and the inferences regarding rotational mobilities, deformation potentials, and alternate structures of nucleic acids that follow from such experiments. Emphasis is mainly on the use of time-resolved fluorescence polarization anisotropy (FPA), although results obtained using other techniques are also noted. This chapter is devoted mainly to free DNAs and tRNAs, but DNAs in nucleosomes, chromatin, viruses, and sperm are also briefly discussed. 

It is obvious that these commonalties can be tailored to achieve successful contraceptive formulations with varying degrees of efficacy, user friendliness, and aesthetics. U.S. marketed contraceptive products all contain N9 as the spermicide at various concentrations. These products rely only on the mechanism of sperm destruction by the nondiscriminating surfactant effects of the spermicide, as effects of the carrier system on sperm motility are generally minimal. No claim of activity against STDs and HIV are made by current contraceptive products, with the exception of full barrier methods such as condoms. 

Spermicides kill sperm. They are not completely effective as contraceptives when used alone but they improve the effectiveness of barrier methods. For centuries, women have used a variety of substances in conjunction with pads or sponges to prevent conception. Acids, such as vinegar, lemon juice and even Coca-Cola, restrict the motility of sperm, so that movement through the vagina is significantly restricted. 

The first electrochemical studies of Mb were reported for the horse heart protein in 1942 (94) and subsequently for sperm whale Mb (e.g., 95) through use of potentiometric titrations employing a mediator to achieve efficient equilibriation of the protein with the electrode (96). More recently, spectroelectrochemical measurements have also been employed (97, 98). The alternative methods of direct electrochemistry (99-102) that are used widely for other heme proteins (e.g., cytochrome c, cytochrome bs) have not been as readily applied to the study of myoglobin because coupling the oxidation-reduction eqiulibrium of this protein to a modified working electrode surface has been more difficult to achieve. As a result, most published electrochemical studies of wild-type and variant myoglobins have involved measurements at eqiulibrium rather than dynamic techniques. 

Pure salmon sperm DNA (41 % dG + dC), from Worthington Biochemical Co., Freehold, New Jersey, USA, was used. Protein content in it was determined by the method of Lowry et al. and found to be less than 1 %. RNA content, determined by Defrance and Delesdain s method was also less than 1 %. DNA absorption... 

One method, first successfully attempted in mice in the 1970s, uses newly fertilized eggs. The researchers use a very fine needle to inject the desired DNA into the area containing the DNA from the sperm, before the sperm and egg have fused. The injected DNA may become part of the sperm DNA. After fusion has occurred, the fertilized egg is allowed to develop into a two-cell embryo, which is then implanted into a female mouse. If the embryo attaches to the uterus, the pregnancy will go forward and healthy pups, or baby mice, will develop. Successful development of transgenic mice is not certain, because only one-third of the embryos placed into a mouse uterus develop into live animals, and only a few may carry the transgene and produce the desired protein. 

Spectroscopic methods, peroxide value, 657 Sperm motility... 

The amendment to ICH S5(R2) says that sperm analysis (counts, motility, morphology) is an optional method to confirm findings and to further characterize effects. However, the necropsy of the males usually occurs prior to final interpretation, and since at least sperm motility requires a living sample, many laboratories routinely incorporate this analysis. 

Sperm analysis is optional (1). The most precise method uses computer assisted sperm analysis (CASA), e.g., Hamilton-Thorne IVOS. Sperm analysis, while not obligatory according to ICH S5(R2), should be performed because one ofthe major mechanisms... 

Chapin RE, Filler RS, Gulati D, Heindel JJ, Katz DF, Mebus CA, Obasaju F, Perreault SD, Russel SR, Schrader S, Slott V, Sokol RZ, Toth G (1992) Methods for assessing rat sperm motility. Reprod Toxicol 8 267-273. 

Methods for assessing sperm motility, morphology, and counts in the rat, rabbit and dog a consensus report. Reprod Toxicol, 10(3) 237-244. 

Protamine sulphate (from herring sperm) [9007-31-2] (a]p -85.5 (satd H2O). A strongly basic protein (white powder) with pKa values of 7.4-8.0 used to ppte nucleic acids from crude protein extracts. It dissolved to the extent of 1.25% in H2O. It is freely soluble in hot H2O but separates as an oil on cooling. It has been purified by chromatography on an IRA-400 ion-exchange resin in the SO form and washed with dilute H2SO4. Eluates are freeze-dried under high vacuum below 20°. This method is used to convert proteamine and protamine hydrochloride to the sulphate. [UV Rasmussen Z physiol Chem 224 97 1934, Ando and Sawada J Biochem Tokyo 49 252 1961, Felix and Hashimoto Z physiol Chem 330 205 1963]... 

---