Less invasive surfactant administration methods: Who, what and how.

Surfactant administration via an endotracheal tube (ETT) has been the standard of care for infants with respiratory distress syndrome for decades. As non-invasive ventilation has become commonplace in the NICU, methods for administering surfactant without use of an ETT have been developed. These methods include thin catheter techniques (LISA, MIST), aerosolization/ nebulization, and surfactant administration through laryngeal (LMA) or supraglottic airways (SALSA). This review will describe these methods and discuss considerations and implementation into clinical practice.

Cholesterol sulfate. II. Studies on its metabolism and possible function in canine blood.

Previous in vitro studies to evaluate the possible role of cholesterol sulfate in the stabilization of the human erythrocyte membrane have been extended to the dog in vivo. Thus, following the injection of labelled cholesterol sulfate, a large fraction of the administered sterol conjugate is taken up by the membrane of the canine erythrocyte. Peak membrane levels were obtained within 30-60 min. Measurement of radioactivity associated with the plasma and red cell fractions in serial samples allowed the calculation of the half-life of cholesterol sulfate in each fraction. From the data obtained from the plasma of four dogs, the half-life was calculated to 5.8 plus or minus 0.9 h. The half-life of chlesterol sulfate associated with the erythrocyte membrane was calculated to be 6.7 plus or minus 1.2 h. In addition, following the intravenous administration of 0.2-0.7 mg of cholesterol sulfate/kg of body weight and withdrawal of serial blood samples, a significant diminution in the degree of hemolysis was observed when the red cells were exposed to hypotonic saline solutions. Maximal stabilization effects were observed at approx. 6-7 h after the administration of the sterol conjugate. Hemolytic properties returned to normal at approx. 24 h following the injection.

The target sizes of the in situ and solubilized forms of human placental steroid sulfatase as measured by radiation inactivation.

Whole microsomal membrane preparations and Triton X-100-solubilized human placental steroid sulfatase were subjected to radiation inactivation analysis using gamma rays from a 60Co irradiator in order to assess the size of the physiological form of the enzyme. The data indicate that the enzyme exists as a monomer of molecular weight 78600 in Triton-containing buffers and as a polymer of molecular weight 533000 within the microsomal membrane.

Metabolism of sex steroids in the human and canine vas deferens.

The contribution of the vas deferens to the metabolism of steroids was investigated in the human and in the dog by perfusion experiments and in vitro incubation. Perfusion of testosterone or androstenedione through the canine vas deferens resulted in the formation of dihydrotestosterone; no significant formation of estrogens could be detected. When dihydrotestosterone was perfused, 3alpha- and 3beta-androstanediols were isolated. In vitro incubation experiments with human was deferencs have shown an active metabolism of androgens by this time and, therefore, confer a new role to the vas deferens in the male.

Preparation and properties of antibodies doubly labeled with tritium and fluorescein.

A method was developed to prepare doubly labeled antibodies whereby fluorescein-labeled antibodies were reacted with N-[ethyl-2-3H]ethylmaleimide. This tritiated conjugate exhibited the same immunoreactivity as the non-derivatized fluorescein-labeled antibody. This method provides a marker for immunocytochemical studies which takes advantage of the rapidity of fluorescent tracing combined with the stability and precision of the radioautography technique.

Sex steroid concentrations in plasma from the canine deferential vein.

Sex steroid concentrations in plasma collected from the canine deferential vein were measured, after separation, by radioimmunoassay. The concentrations found were compared with those in the peripheral plasma. The mean concentrations of androstenedione, testosterone, 5 alpha-dihydrotestosterone, 5 alpha-androstane-3 alpha, 17 beta-diol, 5 alpha-androstane-3 beta, 17 beta-diol and oestradiol-17 beta were 13.2, 14.7, 8.9, 4.6, 8.0 and 7.5 fold higher respectively in plasma from the deferential vein than in peripheral plasma. A close anatomical relationship was found between the vasa deferentia, the deferential vein and the peripheral plasma as well as between the deferential vein and the prostate gland. These findings emphasize and extend earlier conclusions that high levels of sex steroids present in the deferential vein could have a local influence on the growth of the prostate.

Androgen levels in the lipid of the canine vas deferens and peripheral plasma.

Radioimmunoassays were used for the measurement of several androgens in canine plasma and in the liquid of the vas deferens. Large variations in the plasma concentrations of androstenedione, testosterone and 5 alpha-dihydrotestosterone occurred during a period of 24 h, but there was no evidence of a circadian rhythm. The ratios of the androgen concentration in the liquid of the vas deferens compared with that in the peripheral plasma were: androstenedione, 4.6; testosterone, 1.9; 5 alpha-dihydrotestosterone, 13.6; 5 alpha-androstane-3 alpha, 17 beta-diol, 17.0; 5 alpha-diol, 22.4. These high levels of androgens in the liquid of the vas deferens could play a role in the development of prostatic hypertrophy.

Characterization of canine prostatic cells from normal and hyperplastic glands.

Secretory and non-secretory epithelial cells and fibroblasts obtained from normal and hyperplastic canine prostate glands and from prostates of 6-week castrated dogs are cultured in monolayers. Prostatic fibroblasts are grown in non-selective culture medium and found at densities of 1.040-1.045 g/ml in Percoll gradients. Enriched populations of each epithelial cell type area obtained by varying the duration of the culture combined with the use of selective MEM D-Val mixture. When separated by centrifugation in Percoll density gradients, the secretory cells (high A.P.) are found at densities of 1.02-1.03 g/ml whereas the non-secretory cells (low A.P.) have densities of 1.05-1.06 g/ml. Both epithelial cell types are present in the normal and hyperplastic glands at the time of explantation. There is no correlation between the prostatic weight and the proportion of each cell type present in the tissue. On the basis of cell density in Percoll gradients and A.P. activity, those prostates with a high percentage of non-secretory epithelial cells yield better attachment and overall cultures than glands consisting mainly of secretory cells. Our results strongly suggest that non-secretory cells are precursors of the secretory type. In addition, the cells involved in the aging process of the culture are the secretory epithelial cells.

Proliferation and differentiation of canine prostatic epithelial cells in culture.

When cultured in monolayers, non-secretory epithelial cells from canine prostates actively synthesize DNA, RNA and proteins; subsequently, mitotic figures and an increase in cell number are observed. During this culture period, cell size and acid phosphatase activity remain constant. As the culture proceeds, these cells mature into secretory cells as evidenced by a gradual shift in their density in Percoll gradients to the density of secretory cells and by an increase in the cellular content of acid phosphatase. During maturation, the size of the non-secretory cells increases and their morphology changes and becomes similar to that of the secretory cells. When a homogeneous population of secretory cells is cultured, DNA synthesis is minimal and few mitotic figures may be observed while cell number and cell density remain constant. Early in the culture period, their size increases and by 2 weeks their acid phosphatase activity is 2--3-fold higher than that of the non-secretory cells. Thus, upon culture, the non-secretory epithelial cells enter and proceed through the cell cycle with evidence of DNA synthesis and mitosis. Those cells leaving the cycle undergo maturation into secretory cells which further differentiate with the concomitant appearance of acid phosphatase activity. This model will be useful to study prostatic hyperplasia and hypertrophy and the control mechanisms involved in these phenomena.

Induction of acid phosphatase synthesis in canine prostatic epithelial cells in vitro.

The increase in acid phosphatase (AP) activity in cultured canine prostatic epithelial cells was investigated as a biochemical marker of in vitro cellular differentiation. The enzyme was studied in secretory and non-secretory epithelial cell populations obtained from control and cycloheximide-treated cultures over a period of 3 weeks and compared to the AP present in tissue and cellular extracts from normal canine prostates. The progressive increase in AP activity with the duration of culture was strongly inhibited by cycloheximide in both cell populations. The degree of inhibition was more pronounced late in the culture when AP activity increased at a faster rate in secretory cells. Cycloheximide inhibited protein biosynthesis by 70-80% as evidenced by a reduction in the incorporation of amino acids into acid-insoluble material. However, the specific activities of AP in the cellular extracts were similar in control and cycloheximide-treated cultures and increased sharply by 3-4-fold in the secretory cells after 12 days of culture. When extracts derived from control and cycloheximide-treated cells of various duration were submitted to electrophoresis in polyacrylamide gels (PAGE), a unique pattern of three bands of AP activity with Rf values of 0.18, 0.27 and 0.38 was obtained. In controls the AP activity in the band with an Rf of 0.18 increased preferentially during the culture period and was more important quantitatively in secretory cells. In cycloheximide-treated cultures the increase of AP activity associated with the band with an Rf of 0.18 was more strongly inhibited. The addition of tartrate to the staining mixture inhibited all three bands of AP activity. Similar results were obtained when extracts derived from freshly dispersed cells as well as from normal canine prostatic tissue were submitted to PAGE; the AP activity was resolved into 3 bands with Rf values of 0.15-0.18, 0.23-0.27 and 0.33-0.38; all three bands were inhibited by the addition of tartrate and the first band was predominant. Thus, the increase in AP activity in prostatic epithelial cells in a culture medium supplemented with serum and deprived of sex steroids is due to the de novo synthesis of a major form of the enzyme by the secretory cells.

Surgical treatment of congenital pulmonary stenosis due to dysplastic leaflets and small valve anulus.

Seven cases of pulmonary valve stenosis due to congenital dysplasia of the valvular apparatus have been corrected by patch-graft enlargement of the right ventricular outflow tract. The six surviving patients (85%) are now leading normal lives with good exercise tolerance. The satisfactory right ventricular performance, manifested by these subjects after the operation and in the long-term follow-up, supports the validity of the procedure in the presence of a normal right ventricle and tricuspid valve.

Change of blood group from A2 to Ax in a child with congenital abnormalities.

A blood group change from A2 to Ax is described in a boy who had Fallot's tetralogy, oesophageal atresia, and a tracheo-oesophageal fistula. The change of blood group created a transfusion problem. The unusual serology is discussed.

Excess intravascular coagulation complicating low cardiac output.

In 42 children with congenital heart disease coagulation factor levels were studied serially during the first 20 hours following cardiopulmonary bypass surgery. The acyanotic patients, and also cyanotic patients who survived the operation, showed a progressive improvement in their coagulation profile from initial low postoperative levels. In 12 cyanotic patients who died within 72 hours, however, the coagulation factor levels either remained low, or fell further, until death. Fresh frozen plasma was administered to eight of these patients without apparent benefit. The abnormal coagulation profile correlated significantly with low skin temperature and increased blood loss and was considered to represent excess intravascular coagulation secondary to low cardiac output and poor tissue perfusion.

Semen selenium and human fertility.

Selenium (Se) was measured in the semen of 125 men from couples consulting for infertility. A mean concentration of 71.3 +/- 29.7 ng/ml of semen was found, with a range of 7 to 230 ng/ml. More than 85% of the Se is in the seminal plasma. There was a significant positive correlation between sperm count and semen Se. Sperm motility was maximal at semen Se levels ranging between 50 and 69 ng/ml; above and below this range, motility was decreased and the incidence of asthenospermia was high. This result suggests an optimal range for semen Se. A follow-up of 4.5 to 5 years after the initial assay of Se revealed that low semen Se levels (less than or equal to 35 ng/ml) were associated with male infertility. A Se level between approximately 40 and 70 ng/ml was optimal for reproductive performance (high pregnancy rate and low abortion rate). Semen Se levels greater than or equal to 80 ng/ml were associated with a high abortion rate and signs of ovarian dysfunction in the partner (both partners usually have the same diet and environmental exposure). These results attest to the role of Se in human reproduction, a well-established fact in several animal species. The semen Se level appears to be a useful indicator of Se status versus reproductive function. Further studies are warranted concerning the general aspects of metabolism and mechanism of action of Se in infertile couples before any therapeutic modification of intake of this element can be contemplated.

Platelet-activating factor acetylhydrolase in human seminal plasma.

OBJECTIVE: To search for the presence of platelet-activating factor (PAF) acetylhydrolase activity in human seminal plasma. DESIGN: Experimental. SETTING: Reproductive laboratory in a university-affiliated hospital research center. PARTICIPANTS: Human male volunteers were selected on the basis of apparent normal health. RESULTS: Human seminal plasma contained significant levels of PAF-acetylhydrolase activity. Enzymatic hydrolysis of PAF displayed typical kinetics and was a calcium-independent process. Platelet-activating factor acetylhydrolase in seminal plasma was associated with a very high-density lipoprotein fraction. Enzymatic activity was independent of sperm count and motility. CONCLUSION: Human seminal plasma contains significant levels of PAF acetylhydrolase. This enzyme may be an important factor in the regulation of PAF concentration and activity.

Effect of platelet-activating factor, lyso-platelet-activating factor, and lysophosphatidylcholine on sperm motion: importance of albumin for motility stimulation.

OBJECTIVES: To determine the effect of platelet-activating factor (PAF), the PAF derivative lyso-PAF, and lysophosphatidylcholine on in vitro sperm motility and to determine the role of albumin in this interaction. DESIGN: Washed human spermatozoa were exposed to a range of PAF, lyso-PAF, or lysophosphatidylcholine concentrations, supplemented with different albumin concentrations, and the effect on sperm motion was quantified with a computer-assisted motion analysis. The metabolism of these compounds by spermatozoa was also assessed. SETTING: University research laboratory. PATIENTS, PARTICIPANTS: Semen samples were obtained from donors and patients attending an infertility clinic. INTERVENTIONS: Human spermatozoa were incubated with PAF, lyso-PAF, or lysophosphatidylcholine at 10(-11) to 6 x 10(-4) M, with 0% to 1.2% albumin, and motility was evaluated at different time periods from 5 to 240 minutes. Tritiated PAF, lyso-PAF, or lysophosphatidylcholine was incubated with spermatozoa, and the metabolites were separated and quantified by thin-layer chromatography (TLC). MAIN OUTCOME MEASURES: Sperm motion characteristics, including the percentage of motile spermatozoa, velocity, and linearity, and sperm viability were determined. The metabolism of PAF, lyso-PAF, and lysophosphatidylcholine by spermatozoa was also studied. RESULTS: Fifty micromolar of PAF and 100 microM lyso-PAF, supplemented with 0.3% albumin, increased sperm linear velocity by 41% +/- 5% (+/- SEM) and 44% +/- 5% and curvilinear velocity by 17% +/- 3% and 21 +/- 3%, respectively. Lysophosphatidylcholine had a similar effect but only at 22 degrees C and not 37 degrees C. In the absence of albumin, neither PAF, lyso-PAF, or lysophosphatidylcholine induced increases in sperm motion. Lysophosphatidylcholine and lyso-PAF are not detectably metabolized by spermatozoa, whereas 12.5% +/- 1.2% of PAF is hydrolyzed to lyso-PAF in 1 hour. CONCLUSION: Platelet-activating factor, lyso-PAF, and lysophosphatidylcholine independently stimulate sperm linear and curvilinear velocity. This action requires albumin. These compounds may be of use in the treatment of asthenozoospermic males.

Fertilizing capacity and sperm antibodies in vasovasostomized men.

In order to explain the discrepancy between the patency rate (80%) and the pregnancy rate (46%) in a series of vasovasostomies, attention was focused on a group of patients who became normospermic. The mean age at vasectomy, the duration of vasobstruction, and the parameters of semen analysis were not different for those couples who achieved a pregnancy (n = 8), compared with those couples without pregnancy (n = 7). In the group with pregnancy, six of the eight patients had low titers of serum agglutinins (absent to 1:32), and the fertilizing capacity of their spermatozoa was normal. None had immobilizing antibodies. In the group without pregnancy, six of the seven patients had elevated serum agglutinins (greater than 1:256), and four had agglutinating antibodies in their seminal plasma as well as serum immobilizing antibodies. The spermatozoa of seven patients failed to fertilize zona-free hamster ova. It is concluded that a loss of fertilizing ability of the spermatozoa due to sperm antibodies is an important cause of infertility in vasovasostomized men.

Male infertility associated with round-headed acrosomeless spermatozoa.

The properties of spermatozoa with round head syndrome in four unrelated patients are reported. The findings were as follows: (1) Electron microscopy demonstrated that all spermatozoa lacked an acrosome and postacrosomal sheath. (2) Acrosin activity was only 1% to 6% of that found in sperm obtained from fertile donors. (3) Phospholipase A2 activity was not significantly different from that of spermatozoa from donors of unknown fertility. (4) Electrophoresis of whole sperm extracts revealed deficiencies in major protein bands. (5) The round-headed spermatozoa failed to bind or penetrate the vitellus in the egg penetration test. (6) The rates of chemically induced nuclear chromatin decondensation of round-headed spermatozoa suggest that the acrosome content is not involved in this process.

Plasma estrone sulfate levels in postmenopausal women.

Estrone sulfate levels were measured in the plasma of 63 postmenopausal women. The assay method involved prior extraction of the free estrogens, enzyme hydrolysis of the estrone sulfate with sulfatase and radioimmunoassay of the estrone liberated. The plasma levels ranged from 37 to 320 pg/ml (expressed as free estrone) with a mean value of 178 +/- 79 pg/ml. As observed in premenopause, estrone sulfate is quantitatively the most important circulating estrogen in postmenopausal women.

Steroid sulfotransferase in hamster epididymis.

Steroid sulfotransferase activity is present in the cytosol fraction of hamster epididymis. The activity of this enzyme is increased by magnesium ion. Cysteine is essential to assure optimal activity. Adenosine-3'-phosphate-5'-phosphosulfate is required as sulfate donor and an apparent Km of 62 microM was calculated. Inhibition studies suggest that this enzyme preferentially catalyzes the sulfurylation of the 3 beta-hydroxyl group of delta 5-steroids. An unusual feature of the enzyme is a pH optimum at pH 10.