Validity and cost-effectiveness of antisperm antibody testing before in vitro fertilization

OBJECTIVE: To determine the usefulness of and cost-effectiveness of antisperm antibody testing in the prediction of poor fertilization rates in couples undergoing IVF. DESIGN: Retrospective cohort study. SETTING: A hospital-based reproductive endocrinology and infertility practice. PATIENT(S): Male partners of 251 couples undergoing IVF between 1992 and 1997. MAIN OUTCOME MEASURE(S): Fertilization rates in couples undergoing conventional IVF. RESULT(S): One hundred nineteen couples were evaluated for antisperm antibodies; fertilization rates were similar in those couples whose husbands were and were not tested (64% versus 68%). Antisperm antibodies were detected in 16 men. Four (25%) of the 16 couples whose husbands had antisperm antibodies fertilized < or = 50% of oocytes, compared with 31 (30%) of the 103 couples whose husbands did not have these antibodies. Overall, 21 couples (8.4%) experienced complete fertilization failure. In a program that included antisperm antibody testing for selected couples and intracytoplasmic sperm injection (ICSI) for those who tested positive, it would cost $11,735 to prevent a fertilization failure (assuming ICSI were 100% effective), whereas it would cost $9,250 to perform ICSI in a second IVF cycle for those who initially failed. CONCLUSION(S): In this practice setting, antisperm antibody testing has low sensitivity in predicting low or no fertilization and does not appear to be cost-effective when selectively ordered as part of an IVF workup.     

The pulmonary effect of nitric oxide synthase inhibition following endotoxemia in a swine model

OBJECTIVE: To evaluate the pulmonary effect of treatment with N-nitro-L-arginine methyl ester (NAME) with and without inhaled nitric oxide (NO) in a swine model of endotoxemia. DESIGN: Randomized controlled trial. SETTING: Laboratory. INTERVENTIONS: Following a 20-minute intravenous infusion of Escherichia coli lipopolysaccharide (LPS) (200 micrograms/kg), animals were resuscitated with saline solution (1 mL/kg per minute) and observed for 3 hours while mechanically ventilated (fraction of inspired oxygen [FIO2], 0.6; tidal volume, 12 mL/kg; positive end-expiratory pressure, 5 cm H2O). Group 1 (LPS, n = 6) received no additional treatment; group 2 (NAME, n = 5) received NAME (3 mg/kg per hour) for the last 2 hours; group 3 (NO, n = 6) received NAME (3 mg/kg per hour) and inhaled NO (40 ppm) for the last 2 hours; and group 4 (control, n = 5) received only saline solution without LPS. MAIN OUTCOME MEASURES: Cardiopulmonary variables and blood gases were measured serially. The multiple inert gas elimination technique was performed at 3 hours. The wet-to-dry lung weight ratio was measured following necropsy. RESULTS: Administration of LPS resulted in pulmonary arterial hypertension, pulmonary edema, and hypoxemia with increased ventilation perfusion ratio mismatching. None of these changes were attenuated by NAME treatment alone but all were significantly improved by the simultaneous administration of inhaled NO. CONCLUSIONS: Systemic NO synthase inhibition failed to restore hypoxic pulmonary vasoconstriction following LPS administration. The deleterious effects of endotoxemia on pulmonary function can be improved by inhaled NO but not by systemic inhibition of NO synthase.     

Anaesthesia for lambs undergoing spinal surgery: a case series

The purpose of this study was to identify whether the central extracellular fluid volume status following hypo- and hypervolaemia can be measured by the initial distribution volume of glucose or by the extravascular lung water. These two estimates were compared with the initial distribution volume of sucrose which has been used as an indicator for the measurement of the extracellular fluid volume. The above three estimates were determined by the administration of glucose, chilled saline and sucrose solutions, before and after haemorrhage (30 mL kg-1), and subsequent fluid load (lactated Ringer's solution 90 mL kg-1). The distribution volumes of glucose and sucrose decreased after haemorrhage and increased after fluid load compared with normovolaemic values, and a linear correlation was obtained between these two distribution volumes (r = 0.93, P < 0.001, n = 36). However, the extravascular lung water remained statistically unchanged throughout the procedure, despite a weak linear correlation with the sucrose distribution volume (r = 0.38, n = 33, P < 0.05). These results indicate that the initial distribution volume of glucose is more useful as an indicator of the central extracellular fluid volume status than the extravascular lung water.     

Apoptosis of central and peripheral neurons can be prevented with cyclin-dependent kinase/mitogen-activated protein kinase inhibitors

Previous studies have indicated that certain members of the cyclin-dependent kinase/mitogen-activated protein kinase superfamily are involved in apoptosis of neuronal cells. Here, we have examined programmed cell death induced by withdrawal of neurotrophic support from CNS (rat retinal) and PNS (chick sympathetic, sensory, and ciliary) neurons. All four neuron types were equally rescued by the purine analogues olomoucine and roscovitine. Olomoucine inhibits multiple cyclin-dependent and mitogen-activated protein kinases with similar potency. Roscovitine is a more selective cyclin-dependent kinase inhibitor; but, so is butyrolactone I, which did not prevent retinal ganglion cell death. The specific p38MAPK inhibitor SB-203580 did not prevent apoptosis in retinal ganglion cells. Death of these cells in the absence of neurotrophic factors was accompanied by morphological changes indicative of apoptosis, including nuclear condensation and fragmentation. Treatment with olomoucine or roscovitine not only prevented these apoptotic changes in retinal ganglion cells but also blocked neurite outgrowth. The survival-promoting activity of olomoucine correlated with its in vitro IC50 for c-Jun N-terminal kinase-1 and its potency to repress c-jun induction in live PC12 cells. Roscovitine was more potent in rescuing neurons than in inhibiting Jun kinase. Thus, the antiapoptotic action of roscovitine might be due to inhibition of additional kinases.     

Atypical beta-adrenergic receptors in rat liver: evidence for transient expression during aging

This study was designed to determine whether functional beta 3-adrenergic receptors exist in the rat liver and whether there are alterations in the beta 3-adrenergic response with age in a manner similar to that which occurs for beta 2-adrenergic receptors. The beta 3 stimulation of adenylyl cyclase activity was assessed using the novel beta 3-specific agonist, CGP-12177A. Adenylyl cyclase activation by CGP-12177A was seen only in the adults. Isoproterenol-stimulated adenylyl cyclase activity was high in the neonates, declined by 45% in the adults, and was high again in the senescent rats. ICI 118551, a beta 2-selective antagonist, attenuated the isoproterenol-stimulated activity by two-thirds but had no effect on the CGP-12177A-stimulated activity. These data demonstrated the presence of the beta 3-adrenergic receptor in the rat liver, although only at the adult stage of development. In addition, these data confirm earlier findings that beta 2-adrenergic activation of adenylyl cyclase is biphasic with age and indicate that the emergence of the beta 3-stimulated activity coincides with the attenuation of beta 2-stimulated activity.     

Structural characteristics of thylakoid membranes of Arabidopsis mutants deficient in lipid fatty acid desaturation

The ultrastructure of thylakoid membranes from Arabidopsis thaliana wild-type, JB67 and LK3 fatty acid desaturation deficient mutants was studied by thin-section and freeze-fracture electron microscopy. There was a decrease in the amount of the appressed and non-appressed membranes in JB67 and LK3 Arbidopsis mutants when compared to the wild type, resulting in a reduction in the length of photosynthetic membrane per plastid. The results from freeze-fracture showed a decrease in size and a marked increase in packing density of membrane-associated particles on the exo- and endoplasmic fracture faces of the mutants. In addition, areas of the appressed membranes of the mutants contained particles in regular arrays under conditions where no such arrays were observed in wild-type thylakoid membranes. These observations suggest, that the decreased level of lipid fatty acid unsaturation affects the ability of the lipid matrix to mediate the assembly of chloroplast membrane components. The role of polyunsaturated membrane lipids is considered in terms of their ability to promote functional oligomeric assemblies of components of the photosynthetic apparatus.     

Cell surface glycosaminoglycans do not serve as ligands for PECAM-1. PECAM-1 is not a heparin-binding protein

Previous studies have suggested that PECAM-1 mediates cellular interactions via both homophilic and heterophilic adhesive mechanisms. Cell surface glycoaminoglycans have been implicated as one of the heterophilic ligands for PECAM-1. To determine whether PECAM-1 is capable of interacting directly with glycosaminoglycans, we examined the adhesive properties of multiple monovalent and multivalent forms of this adhesion molecule. We found that the binding of a bivalent PECAM-1/IgG chimeric protein or multivalent PECAM-1-containing proteoliposomes to multiple different cell lines was 1) strictly dependent upon cell surface expression of PECAM-1 and 2) unaffected by the presence of excess heparin or heparan sulfate. The extracellular domain of PECAM-1 failed to interact specifically with heparin-Sepharose, 3H-labeled heparin, or a heparin-bovine serum albumin conjugate. In addition, an amino acid sequence motif inadvertently created by the juxtaposition of PECAM-1 and IgG sequences within the hinge region of certain PECAM-1/IgG chimeric constructs was found to confer glycosaminoglycan binding properties not normally present within the extracellular domain of the native molecule. Together, these data suggest that the mechanism by which heparin is able to affect PECAM-1-dependent cell-cell adhesion is indirect and occurs via inhibition of events that occur downstream from PECAM-1 engagement.     

Effect of diaspirin cross-linked hemoglobin on endothelin-1 and blood pressure in acute ischemic stroke in man

OBJECTIVE: For almost 50 years it has been known that hemolysed blood can increase blood pressure. Although preclinical studies suggest that this pressor response is due to an interaction of hemoglobin with endothelium-derived vasoactive substances, its mechanism in humans is unknown. We investigated the involvement of endothelin-1 in the blood pressure response to the oxygen carrier diaspirin cross-linked hemoglobin (DCLHb) in stroke patients. DESIGN: In a randomized phase II study, increasing doses of DCLHb (25, 50 and 100 mg/kg, n=8, 8 and 11, respectively) or placebo (n=26) were infused intravenously every 6 h for 72 h to patients with an acute ischemic stroke. Blood pressure and heart rate were measured every 15 min and plasma concentrations of endothelin-1, catecholamines, renin, vasopressin and atrial natriuretic peptide were measured before and 24 and 66 h after the start of the infusions. RESULTS: In the placebo group, mean arterial pressure (MAP) was 112 (109-115) mmHg (mean and 95% confidence interval) at baseline and decreased spontaneously by 11.4 (5.4-17.5) and 12.5 (5.4-19.5) mmHg after 24 and 66 h, respectively. This decrease in MAP was attenuated in patients treated with DCLHb, reaching statistical significance in the highest dose group. The plasma endothelin-1 concentration decreased slightly in the placebo group, from 4.2 (3.1-5.3) pg/ml (median and range) at baseline to 2.4 (1.9-3.7) pg/ml after 24 h (P=0.0044) and 2.8 (1.9-3.7) pg/ml after 66 h (P=0.0042), but increased dose-dependently in response to DCLHb infusion. With the highest dose of DCLHb, the plasma endothelin-1 concentration rose from 4.8 (0.1-7.8) pg/ml at baseline to 21.2 (13.4-53.2) pg/ml after 24 h (P< 0.001) and to 27.6 (11.9-47.8) pg/ml after 66 h (P< 0.001). The increases in the plasma endothelin-1 concentration and in MAP were correlated (r=0.30, P=0.02). Other vasoactive hormones were not affected by the DCLHb infusion. CONCLUSIONS: Infusion of DCLHb in patients with acute ischemic stroke was associated with a dose-dependent increase in plasma endothelin-1 concentration. This may underlie the attenuation by DCLHb of the natural decrease in blood pressure that we observed in these patients.