Ovarian stimulation by clomiphene citrate and hMG in combination with cetrorelix acetate for ICSI cycles

BACKGROUND: The introduction of GnRH antagonists such as cetrorelix acetate has made possible the simplification of ovarian stimulation. However, the most effective protocol for their administration has not yet been clearly defined. METHODS: Forty women with male-factor infertility undergoing 40 ICSI cycles were included in the study. Clomiphene citrate at 100 mg a day was given from cycle day 3 through day 7. hMG at 150 IU was given on cycle days 4, 6 and 8, and was adjusted from day 9 according to the follicular and hormone responses. Cetrorelix acetate at 2.5 mg was administered when the leading follicle reached 14 mm. The remaining 0.5 mg was divided into two 0.25 mg injections for possible later use. Serum FSH, LH, estradiol and progesterone levels were measured daily from the day of cetrorelix acetate injection until hCG was given. RESULTS: Serum LH level was suppressed effectively for 4 days. Four patients (10%) needed one or two additional injections of 0.25 mg cetrorelix acetate. No premature LH surge was detected in any of the women treated. Sixteen women became pregnant (40%), of which 14 pregnancies (35%) were ongoing at the time of writing. CONCLUSIONS: This study demonstrates that this new protocol is feasible for couples with male-factor infertility undergoing ICSI.     

Effects of enclomiphene and zuclomiphene on basal and gonadotrophin-stimulated progesterone secretion by isolated subpopulations of small and large ovine luteal cells

We examined the effects of enclomiphene and zuclomiphene, aloneand in combination with oestradiol, on basal and gonadotrophin-stimulatedprogesterone secretion by isolated subpopulations of both large(granulosa-lutein) and small (theca-lutein) ovine luteal cells.Isolated large and small luteal cells derived from intact, enucleatedovine corpora lutea were incubated for 48–120 h with orwithout 22R-hydroxycholesterol or pregnenolone (2.5 µM)and a range of enclomiphene, zuclomiphene, and/or oestradiolconcentrations (3–100 µM), both with and withoutovine Iuteinizing hormone (100 ng/ml). Spent media were assayedin duplicate for progesterone content by radioimmunoassay. Enclomiphene,zuclomiphene, and oestradiol exhibited equivalent dose-dependentinhibitory effects on basal and gonadotrophin-stimulated smalland large ovine luteal cell progesterone secretion under allsubstrate conditions. Both cell types became more sensitiveto clomiphene inhibition with increasing time in culture. Incombined treatments, the effects of oestradiol and either enclomipheneor zuclomiphene became additive in longer-term cultures andwere never antagonistic In this model system, (i) clomiphene,like oestradiol, appears to inhibit 3-hydroxysteroid dehy-drogenaseactivity, (ii) both stereoisomers act as oestrogen agonists,(iii) neither demonstrates any anti-oestrogenic properties,and (iv) both large and small luteal cells become more sensitiveto clomiphene inhibition with increasing duration of exposure.     

Effect of extracellular volume expansion on renal cortical and medullary Na+−K+-ATPase

Summary The role of renal Na⁺–K⁺-ATPase in the acute changes in sodium reabsorption caused by isotonic volume expansion was evaluatedin vivo andin vitro in the rat and the dog. Duringin vivo volume expansion with isotonic saline in the rat, renal medullary Na⁺–K⁺-ATPase specific activity increased, while the simultaneously determined cortical Na⁺–K⁺-ATPase specific activity and kinetics remained unchanged. Furthermore, experimentsin vitro failed to demonstrate a circulating inhibitor of renal Na⁺–K⁺-ATPase both in plasma dialysates from volume-expanded rats and in plasma dialysates concentrated 20-fold by ultrafiltration from volume-expanded dogs. These results suggest that the decreased proximal tubular reabsorption of sodium during volume expansion is not mediated by inhibition of renal cortical Na⁺–K⁺-ATPase. The acute increment in medullary Na⁺–K⁺-ATPase observed could represent an adaptive response to increased sodium reabsorption by the loops of Henle, and raises the possibility that this enzyme may participate in relatively rapid adjustments in the transport of sodium by the renal tubule.     

The concentrative nucleoside transporter family,SLC28

The SLC28 family consists of three subtypes of sodium-dependent, concentrative nucleoside transporters, CNT1, CNT2, and CNT3 (SLC28A1, SLC28A2, and SLC28A3, respectively), that transport both naturally occurring nucleosides and synthetic nucleoside analogs used in the treatment of various diseases. These subtypes differ in their substrate specificities: CNT1 is pyrimidine-nucleoside preferring, CNT2 is purine-nucleoside preferring, and CNT3 transports both pyrimidine and purine nucleosides. Recent studies have identified key amino acid residues that are determinants of pyrimidine and purine specificity of CNT1 and CNT2. The tissue distributions of the CNTs vary: CNT1 is localized primarily in epithelia, whereas CNT2 and CNT3 have more generalized distributions. Nucleoside transporters in the SLC28 and SLC29 families play critical roles in nucleoside salvage pathways where they mediate the first step of nucleotide biosynthesis. In addition, these transporters work in concert to terminate adenosine signaling. SLC28 family members are crucial determinants of response to a variety of anticancer and antiviral nucleoside analogs, as they modulate the entry of these analogs into target tissues. Further, this family is involved in the absorption and disposition of many nucleoside analogs. Several CNT single nucleoside polymorphisms (SNPs) have been identified, but have yet to be characterized.     

The effects of anesthesia on the excretion of an isotonic saline load in the rat

The ability to excrete a volume of isotonic saline equal to 10% of body weight infused over 60 min, was examined in awake rats and in rats anesthetized with 1 of the 2 agents most commonly used in renal clearance studies, Inactin or Nembutal. Rats anesthetized with Inactin excreted significantly less of the infused sodium during the period of infusion and in the 120-min post-infusion periods as compared to Nembutal-anesthetized rats or awake rats. Following saline infusion, there was a significantly greater decrease in serum protein concentration (25.5±4.7%) in rats anesthetized with Inactin, compared to that observed in the awake or Nembutal-treated rats. In a separate group of saline-infused awake rats, induction of anesthesia with Inactin resulted in a significant increase in hematocrit and a decrease in serum protein concentration. These studies suggest that Inactin anesthesia decreases the ability of the kidney to excrete a saline load and that, in studies of sodium excretion in the rat, especially if volume expansion is to be part of the experimental protocol, Nembutal rather than Inactin may be the anesthetic of choice.These studies were performed while Drs. Knight and Frankfurt were Fellows in Nephrology of Baylor College of Medicine, and were supported in part by a Clinical Investigatorship award to Dr. Weinman and an Associate Investigatorship award to Dr. Frankfurt from the Veterans Administration. This work was presented in part at the Combined Session, Southern Section, American Federation for Clinical Research and the Southern Society for Clinical Investigation, New Orleans, Louisiana, January 27–29, 1977, and has appeared in abstract form in Clin. Res.25, 61 A (1977)     

Effekte einer Captopriltherapie auf die Natrium- und Wasserausscheidung bei Patienten mit Leberzirrhose und Aszites

Summary Ascites in patients with cirrhosis of the liver frequently is refractory to diuretic treatment. It was postulated that vasoconstriction of the renal cortex, mediated by activation of the renin-angiotensin-aldosterone-system (RAAS), may be one course of the disturbed sodium- and water-excretion in these patients. We therefore investigated in 14 cirrhotic patients with ascites under constant diuretic treatment the effects of low-dose captopril therapy on urinary sodium- and potassium-excretion, body weight, abdominal girth, serum-sodium,-potassium, creatinine-clearance, plasma-renin-activity (PRA), plasma-aldosterone (PA) and mean arterial pressure (MAP). After a control period of 4 days the patients received 2 × 6.25 mg/d captopril for 5 days and 4 × 6.25 mg/d for further 5 days. Treatment was followed by a second control period without captopril.PRA increased significantly after 2 days of captopril treatment. 2 × 6.25 mg/d captopril induced a significant increase in sodium excretion and a significant decrease of body weight. MAP decreased slightly but significantly without clinical signs of hypotension. 4 × 6.25 mg/d captopril resulted in a further reduction of body weight and a further enhancement of sodium excretion. Three days after withdrawal of captopril sodium output was significantly reduced again. Conclusion: In cirrhotic patients low-dose captopril seems to be efficient in the treatment of ascites resistant to diuretics without causing major side effects.

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Abkürzungen ACE Angiotensin-Converting-Enzym - A-II Angiotensin II - C_{H 2 O} Frei-Wasser-Clearance - C_Krea Kreatinin-Clearance - C_Osmo Osmolale Clearance - g Gramm - h Stunde - kg Kilogramm - l/d Liter pro Tag - MAP Mittlerer arterieller Blutdruck - mg Milligramm - mg/d Milligramm pro Tag - ml/min Milliliter pro Minute - mmHg Millimeter Quecksilbersäule (Torr) - mmol/d Millimol pro Tag - NaCl Natriumchlorid - ng/ml/h Nanogramm pro Milliliter und Stunde - PA Plasma-Aldosteron - pg/ml Picogramm pro Milliliter - PRA Plasma-Renin-Aktivität - RAAS Renin-Angiotensin-Aldosteron-System - SEM Standardfehler des Mittelwertes - S_Krea Kreatininkonzentration im Serum - S_Osm Serum-Osmolalität - U_Krea Kreatininkonzentration im Urin - U_Osm Urin-Osmolalität - V Urinminutenvolumen - vgl. vergleiche - µmol/l Micromol pro Liter     

Electrophysiology of rat distal colon after partial nephrectomy

Previous in vivo studies in rat and man indicate that chronic renal insufficiency leads to an increase in the capacity of the large intestine for K secretion. The present studies were performed in isolated rat distal colon with conventional and K-sensitive microelectrodes to determine the cellular basis for enhanced colonic K secretion after 70% nephrectomy. The data revealed that in animals fed a regular diet, nephrectomy had no effect on the Na or K conductance of the apical membrane, or the kinetics of the basolateral membrane Na-K pump, but intracellular K activity decreased from 70±4 mmol/l to 58±4 mmol/l (P<0.005). In control (non-nephrectomised) animals, feeding a diet modestly (4-fold) enriched with K resulted in small but significant increases in the Na and K conductance of the apical membrane, no change in the kinetics of the basolateral membrane Na-K pump, and a rise in intracellular K activity from 70±4 mmol/l to 94±7 mmol/l (P<0.005). In contrast, in animals fed the K enriched diet, nephrectomy resulted in (i) large, amiloride-sensitive increases in transepithelial voltage and total tissue conductance (consistent with an appreciable degree of secondary hyperaldosteronism), (ii) marked increases in the Na and K conductance of the apical membrane, (iii) significant hyperpolarisation of the basolateral membrane, (iv) a 100% increase (P<0.02) in the maximum activity of the basolateral membrane Na-K pump, and (v) a rise in intracellular K activity from 94±7 mmol/l to 129±7 mmol/l (P<0.0025). These data suggest that the combination of modest dietary K enrichment and 70% nephrectomy stimulated an active K secretory process which reflected an increase in the K excretory load applied to the colonic mucosa, and the effects of aldosterone. In this model of renal insufficiency, enhanced K secretion by the transcellular and paracellular (potential-dependent) pathways results in a marked rise in the K excretory capacity of the colon.     

Identification, isolation, and characterization of a species-specific 30-kDa antigen of Oesophagostomum dentatum

In the search for a serology tool for the diagnosis of nonpatent as well as patent infections with Oesophagostomum dentatum in pigs a water-soluble, unglycosilated antigen of about 30 kDa specific for the third-stage larvae of the parasite was purified by ion-exchange chromatography. In Western blots, the antigen was first detected by antibodies at day 7 postinfection. Cross-reactivity with O. quadrispinulatum, Ascaris suum, or Trichuris suis was not detected. It is suggested that this protein is a suitable tool for the species-specific serodiagnosis of O. dentatum infection in pigs. Received: 15 June 1998 / Accepted: 28 September 1998     

Sodium nitroprusside and cGMP decrease Ca2+ channel availability in basilar artery smooth muscle cells

 We studied the effect of the nitric oxide (NO) donor, sodium nitroprusside (SNP), on the macroscopic and single-channel currents due to the 22-pS Ca²⁺ channel in smooth muscle cells from guinea pig basilar artery. In nystatin-perforated whole-cell recordings, 50 nM SNP decreased the macroscopic current to 63±12% of control values, without changing the voltage dependence of the current. In cell-attached patches with BAY-K8644 in the pipette, SNP caused a comparable decrease in single-channel availability (n ·P _o) that was dose dependent over the range of 10 nM to 10 μM SNP. SNP had no effect on single-channel properties, including slope conductance, voltage dependence of activation, the number of open states, the time constants of the open states, and the proportion of time spent in each open state. The effect of SNP (50 nM) on single Ca²⁺ channel openings was reproduced by 8-Br-cGMP (100 μM), which also reduced channel availability without altering channel properties. The protein kinase inhibitor H-8 (1.5 μM), which exhibits relative specificity for cGMP-dependent protein kinase, completely inhibited the decrease in single-channel availability expected with SNP. The dose-dependent decrease in Ca²⁺ channel availability caused by SNP was not altered by prior application of 8-Br-cAMP or forskolin, both of which cause an increase in Ca²⁺ channel availability in these cells. Our findings suggest that NO decreases openings of Ca²⁺ channels in basilar artery smooth muscle cells without altering channel properties, and that it does so by a mechanism likely to involve cGMP-dependent protein kinase. Received: 2 July 1996 / Received after revision: 30 September 1996 / Accepted: 2 October 1996     

Amiloride-sensitive Na+ transport across cultured renal (A6) epithelium: evidence for large currents and high NaK selectivity

Electrical techniques were used to determine the NaK selectivity of the amiloride-sensitive pathway and to characterize cellular and paracellular properties of A6 epithelium. Under control conditions, the mean transepithelial voltage (V _T) was –57±5 mV, the short-circuit current (I _sc) averaged 23±2 A/cm² and the transepithelial resistance (R _T) was 2.8±0.3 kcm² (n=13). V _T and I _sc were larger than reported in previous studies and were increased by aldosterone. The conductance of the amiloride-sensitive pathway (G _amil) was assessed before and after replacement of Na⁺ in the mucosal bath by K⁺, using two independent measurements: (1) the slope conductance (G _T), determined from current-voltage (I-V) relationships for control and amiloride-treated tissues and (2) the maximum amiloride-sensitive conductance (G _max) calculated from the amiloride dose-response relationship. The ratio of G _amil in mucosal Na⁺ solutions to G _amil for mucosal K⁺ solutions was 22±6 for G _T measurements and 15±2 for G _max data. Serosal ion replacements in tissues treated with mucosal nystatin indicated a potassium conductance in the basolateral membrane. Equivalent circuit analyses of nystatin and amiloride data were used to resolve the cellular (E _c) and paracellular (R _j) resistances (5 kcm² and 8–9 kcm², respectively). Analysis I-V relationships for tissues depolarized with serosal K⁺ solutions revealed that the amiloride-sensitive pathway could be described as a Na⁺ conductance with a permeability coefficient (P _Na)=1.5±0.2× 10^–6 cm/s and the intracellular Na⁺ concentration (Na_i)=5±1 mM (n=5), similar to values from other tight epithelia. We conclude that A6 epithelia are capable of expressing large amiloride-sensitive currents which are highly Na⁺ selective.