The effect of steroids on the in vitro migration of washed human spermatozoa in modified Tyrode's solution or in fasting human blood serum

In modified Tyrode's solution, 17 beta-estradiol at concentrations between 0.1 microgram/ml and 320 nmoles/ml was effective in increasing human spermatozoal forward migration. 17 alpha-Estradiol, although structurally similar to 17 beta-estradiol, had no effect on human spermatozoal motility. DL-Norgestrel at concentrations between 0.1 migrogram/ml and 320 nmoles/ml inhibited spermatozoal motility. These stimulatory and inhibitory effects were not observed when fasting human blood serum was used as a penetration medium in place of the modified Tyrode's solution. Also, the motility of spermatozoa suspended in fasting human blood serum was better than that of spermatozoa suspended in modified Tyrode's solution or in seminal plasma. These observations indicated that there is a component(s) of fasting human blood serum which increases spermatozoal motility and can counteract the activation or inhibition of spermatozoal motility by 17 beta-estradiol or DL-norgestrel at the concentrations used here.

The presence of complement in human cervical mucus and its possible relevance to infertility in women with complement-dependent sperm-immobilizing antibodies

Full-complement component lytic activity was measured in human midcycle cervical mucus, using a sensitive 51Cr release hemolytic assay. The level measured was 11.5% of the activity of complement in an equal volume of undiluted human serum. The relevance of this level of complement to complement-dependent sperm-immobilizing antibody activity was studied. After 1 hour's incubation with mucus levels of complement, immobilization of about 50% of spermatozoa occurred and after 3 hours' incubation, immobilization of about 70% of spermatozoa occurred.

Binding of steroids to human spermatozoa and its possible role in contraception

The binding of steroids to human ejaculated spermatozoa and the effect of steroids bound to spermatozoa on sperm migration and motility in vitro was examined. A correlation between progestogens that bind to steroid-binding sites on human spermatozoa and progestogens that inhibit sperm migration was established. The results indicated that there is a direct and specific steroid effect on human spermatozoa, as some steroids such as progesterone, lynestrenol, and norethynodrel markedly inhibited sperm migration and motility, whereas other steroids such as estrone had no detectable effect on sperm migration and motility. The significance of these findings was discussed in relation to the contraceptive action of steroids applied directly to the lumen of the female genital tract.

Isolation of human lactate dehydrogenase isoenzyme X by affinity chromatography

Human isoenzyme LDH-X (lactate dehydrogenase isoenzyme X) was isolated from seminal fluid of frozen semen samples by affinity chromatography by using oxamate-Sepharose and AMP-Sepharose. In the presence of 1.6 mM-NAD+, isoenzyme LDH-X does not bind to AMP-Sepharose, whereas the other lactate dehydrogenase isoenzymes do. This is the crucial point in the isolation of isoenzyme LDH-X from the other isoenzymes. The purified human isoenzyme LDH-X had a specific activity of 146 units/mg of protein.

The metabolism and motility of human spermatozoa in the presence of steroid hormones and synthetic progestagens

The metabolism and motility of human ejaculated spermatozoa incubated in vitro with steroids were studied. Progesterone and norethynodrel depressed the respiration, glycolytic metabolism and the motility of washed spermatozoa. Lynoestrenol did not affect the respiration or glycolysis of the spermatozoa, but did inhibit motility. Oestradiol did not cause any consistent alteration of the sperm metabolism, and did not affect the motility. Progesterone and norethynodrel appeared to act on the plasma membrane of human spermatozoa to increase its permeability and hence to facilitate the loss of essential cofactors required for the glycolytic and oxidative processes.

Studies on blood from the original Rhnull proposita and relatives

A relative of the original Rh proposita, of group R1R2, shows weak expression of his Rh antigens, and is thought to be an Rhnull heterozygote. His wife and 3 of their 4 children show normal Rh antigen expression, but one daughter showed weak Rh antigen expression, as determined by quantitative haemagglutination. The observations support the proposition that the father is heterozygous for an unlinked modifier of Rh antigen expression. Stomatocytosis, observed in the Rhnull proposita and other Rhnull individuals, was also observed, but to a lesser degree, in the blood of an other individual thought to be an Rhnull heterozygote. This observation also supports the earlier conclusion that the Rhnull phenotype of the proposita is due to homozygosity for inactive alleles at a locus which controls the biosynthesis of precursor for Rh and LW antigens. Osmotic fragility tests showed that the Rhnull cells were more fragile than cells with normal Rh antigen expression, and cells from Rhnull heterozygotes had intermediate fragility. This is consistent with the proposition that Rh antigens are normal structural components of the red cell membrane, and the Rhnull heterozygotes show a deficiency of the Rh antigenic structures.

Oxygen Binding of Monotrene Haemoglobins II. Fixation of Functionally Non-equivalent Haemoglobins in the Echidna Population

The echidna, Tachyglossus aculeatus, has two haemoglobins and polymorphic variants of both have been described. Haemoglobins Hb-IA, Hb-IB and Hb-IIA have been separated and their oxygen binding parameters studied. Hb-IIA has a markedly higher oxygen affinity and lower cooperativity than the polymorphs ofhaemoglbin I. In phosphate buffer, pH 7�1 and 25�C, Hb-IIA has an oxygen half-saturation pressure (Pso) of 1�3 kPa and a Hill coefficient of 2�4, whereas the polymorphic forms of Hb-I have P so values of about 1�6 kPa and Hill coefficients of about 2�9. Differences in diphosphoglyceric acid interactions account for some of these differences. When the polymorphic forms of haemoglobin I were compared at pH 7 �1, Hb-IA had a AHo value of -27�9 kJjmol and a Hill coefficient of 2�9, whereas Hb-IB had a AHo value of -31�7 kJjmol and a Hill coefficient of 3�0.

Sequence of action of genes at the secretor, H, ABO and Lewis loci

It is argued that Lewis genes are responsible for adding specificity to glycoprotein molecules after the activities of the secretor, H and ABO genes, respectively, have been expressed. This conclusion is based on the results of studies on the expression of ABO and Lewis antigens in salivas from Australian aborigines, and on biochemical results. A simple figure illustrating the antigens determined on red cells and in body secretions as a result of the action of these genes, in their correct order--secretor, H, ABO, Lewis--is presented.

Specificity and possible origin of anti-N antibodies developed by patients undergoing chronic haemodialysis

Studies were performed on two anti-N sera from patients who had formed anti-N antibodies during their period of haemodialysis. No specific inhibition of these antibodies was obtained by extracts prepared from a new and a used dialysis unit, and it was concluded that there was no evidence of a compound in the units which would stimulate production of the anti-N. The specificity of the anti-N's was shown to be against a precursor of MN antigens, since all activity in the sera could be removed by neuraminidase-treated M cells, which expressed MN precursor. Since the anti-N's would react with untreated N cells only at 4 degrees C, but with formaldehyde-treated cells at 4, 25 and 37 degrees C, it was concluded that the specificity of the anti-N's was directed against an antigen developed by red cells after formaldehyde treatment. It is proposed that the production of the anti-N antibodies is stimulated by formaldehyde-treated red cells passing into the patient during re-use of a dialysis unit sterilized with formaldehyde.

The origin of serum protein, A, B, and H blood group, and Gm and Inv antigens in house dust

Materials precipitated from an aqueous extract of house dust by saturation with ammonium sulphate showed immunological reaction with antisera to human serum albumin, human alpha1-acid glycoprotein, human IgG, Gm and Inv antigens and to A, B and H antigens. It is concluded that the albumin and alpha1-acid glycoprotein are of human origin. It seems that the apparent IgG activity is due to cross-reactivity since, from the anticipated specificities of the Fab and Fc fragments of human IgG, the former could not be detected, and since Gm (6) activity was present, unexpectedly, in Swiss house dust. The A, B and H blood group antigenic activities were detected in relative concentration different from those expected if they were solely of human origin. It is concluded that they are from both human and non-human sources.

Fluorine-19 as a covalent active site-directed magnetic resonance probe in aspartate transaminase

Phosphypyridoxyl trifluoroethylamine has been synthesized as an active site-directed 19F NMR probe for aspartate transaminase. This coenzyme derivative adds stoichiometrically to the apotransaminase as observed by both fluorescence and circular dichroism measurements. The fluorinated phosphypyridoxamine derivative, when bound to the apotransaminase, will not dissociate upon extensive dialysis or passage through Sephadex G-25. The compound behaves as a pyridoxamine phosphate derivative and not as a coenzyme-substrate complex, since both competing anions and dicarboxylic acid inhibitors still bind to the phosphopyridoxyl trifluoroethylamine enzyme. The 19F NMR spectra of the enzyme-bound phosphopyridoxyl trifluoroethylamine were measured as a function of pH, ionic strength, and temperature. The 19F MNR of the enzyme-bound coenzyme derivative revealed no predetermined asymmetry in the subunits of aspartate transaminase insolution in terms of differences in chemical shift or resonance line shape between the two environments. A pH-dependent chemical shift change of the single 19F resonance was observed, which is consistent with the influence of a single ionization with an apparent pKa of 8.4 in 0.10 M KCl at 30 degrees. Increasing the ionic strength resulted in increasing values for the observed pKa, the highest recorded value was 9.1 in 3.0 M KCl. The temperature dependence of the pH titration of the chemical shift gives deltaH' of ionization of 10.5 kcal/mol. The evidence suggests a possible epsilon-amino group, electrostatically affected by positive charges, being responsible for the titration effect of the active site-bound fluorine derivative of pyridoxamine phosphate.

Hybridization of glutamate aspartate transaminase. Investigation of subunit interaction

Glutamate aspartate transaminase (EC 2.6.1.1) is a dimeric enzyme with identical subunits with each active site containing pyridoxal 5'-phosphate linked via an internal Shiff's base to a lysine residue. It is not known if these sites interact during catalysis but negative cooperativity has been reported for binding of the coenzyme (Arrio-Dupont, M. (1972), Eur. J. Biochem. 30, 307). Also nonequivalence of its subunits in binding 8-anilinonaphthalene-1-sulfonate (Harris, H.E., and Bayley, P. M. (1975), Biochem. J. 145, 125), in modification of only a single tyrosine with full loss of activity (Christen, P., and Riordan, J.F. (1970), Biochemistry 9, 3025), and following modification with 5,5'-dithiobis(2-nitrobenzoic acid) (Cournil, I., and Arrio-Dupont, M. (1973), Biochemie 55, 103) has been reported. However, steady-state and transient kinetic methods as well as direct titration of the active site chromophore with substrates and substrate analogs have not revealed any cooperative phenomena (Braunstein, A. E. (1973), Enzymes, 3rd Ed. 9, 379). It was therefore decided that a more direct approach should be used to clarify the quistion of subunit interaction during the covalent phase of catalysis. To this end a hybrid method was devised in which a hybrid transaminase was prepared which contained one subunit with a functional active site while the other subunit has the internal Shiff's base reduced with NaBH4. The specific activities and amount of "actively bound" pyridoxal 5'-phosphate are both in a 2:1 ratio for the native and hybrid forms. Comparison of the steady-state kinetic properties of the hybrid and native enzyme forms shows that both forms gave parallel double reciprocal plots which is characteristic of the Ping-Pong Bi-Bi mechanism of transamination. The Km values for the substrates L-aspartic acid and alpha-ketoglutaric acid are nearly identical while the Vmax value for the hybrid is one-half the value of the native transaminase. It therefore appears that the active sites of glutamate aspartate transaminase function independently and a compulsory flip-flop mechanism is not involved.