Effects of bile acids on ventricular muscle contraction and electrophysiological properties: studies in rat papillary muscle and isolated ventricular myocytes

Summary The effects of sodium salts of various bile acids on the contractile force and the electrophysiological properties of rat ventricular muscle were studied in vitro. Primary, conjugated, and secondary bile acids were studied in a concentration range of 10^–9–10^–6 mol/l, which corresponds to concentrations found in the plasm of patients with cholestatic jaundice. In general, the bile acid induced a negative inotropic effect which was manifested as a reduction in active tension, maximum rate of tension activation, and maximum rate of tension relaxation. Twitch duration and time to peak tension were unaffected by the bile acids. The negative inotropism was associated with a reduction in ventricular action potential duration. Resting potential, action potential amplitude, and maximum upstroke velocity of phase 0 depolarization were unaffected. Voltage clamp experiments in rat ventricular myocytes demonstrated that sodium taurocholate decreased the slow inward current and slightly increased the outward potassium current. Hence, these effects on the membrane currents are probably responsible for the negative inotropic effect. Send offprint requests to O. Binah at the above address     

Primary gastrointestinal lymphomas in Turkey: a retrospective analysis of clinical features and results of treatment.

Thirty-three patients with primary gastrointestinal lymphoma (GIL) followed at Ankara University Medical School have been evaluated. The most frequent locations of the disease are the small intestine (48.4%) and the stomach (39.3%). The intermediate and high grade lymphomas constitute 84.8% of the cases. The mean age of the patients with small intestinal lymphoma is 28.7 years and 47.1 years for those with gastric lymphoma. The patients treated with surgery and chemotherapy (S+CT) have a longer survival than those treated with chemotherapy (CT) alone. In conclusion: 1) Small intestinal lymphoma occurs more frequently than gastric lymphoma in our study. 2) The median age of the Turkish patients with primary GIL is approximately 10 years less than those in the Western countries. 3) The therapeutic results of S+CT are superior to those of CT in the early stages of the disease.     

Cryopreserved cadaveric allografts for treatment of unexcised partial thickness flame burns: clinical experience with 12 patients

Partial thickness burns (PTB) usually heal within 3 weeks. Prevention of infection and desiccation of the wounds are crucial for optimal healing. Early tangential excision of the burn eschar and allografting prevent deepening of the burns, and are therefore advocated for treatment with the best functional and aesthetic results. For superficial partial thickness burns (SPTB) conservative use of topical antimicrobial agents with frequent dressing changes are implemented. We compared the conservarive treatment for PTBs and SPTBs to grafting cryopreserved cadaveric allografts with no prior excision.

Twelve patients with flame PTB areas were allografted after mechanical debridement without excision of the burn wounds. The allografts were cadaveric skin cryopreserved by programmed freezing and stored at −180°C for 30–48 months. Matching burns for depth and area were treated with silver sulfadiazine (SSD) one to two times daily until healing or debridement and grafting were required.

It was found that 80 per cent of the cryopreserved allografts adhered well and 76 per cent of the treated areas healed within 21 days, whereas only 40 per cent of the SSD-treated burns healed within 21 days.

Partial thickness burns can be treated successfully with viable human allografts (cryopreserved cadaveric skin) with no prior surgical excision. The burn wounds heal well within 3 weeks. For deep partial thickness burns (DPTB) treatment with allografts has no advantage if they have not been previously excised.     

A 47,XXY fetus conceived after ICSI of spermatozoa from a patient with non-mosaic Klinefelter's syndrome: case report

The birth of 12 healthy infants to fathers with non-mosaic Klinefelter's syndrome has been reported so far. The spermatozoa for these pregnancies was obtained from frozen-thawed ejaculate in one pregnancy (twins) and from the testis in the remaining 10 infants. All of them had a normal karyotype. We describe a patient with non-mosaic Klinefelter's syndrome from whom a testicular biopsy was obtained and motile spermatozoa were collected. Of 16 oocytes that were injected, 14 fertilized and cleaved. Three embryos were transferred, resulting in a triplet pregnancy. Karyotype analysis from chorionic villous sampling revealed 46,XX, 46,XY and 46,XXY from the three fetuses. The affected 46,XXY fetus was reduced on the 14th gestational week. The pregnancy culminated with the birth of a healthy male and female, on the 36th gestational week, weighing 3600 and 2660 g respectively. This case report proves the presence of hyperploid spermatozoa in the seminiferous lumen, and strengthens the necessity of genetic diagnosis of the embryos or fetuses in such pregnancies to fathers with non-mosaic Klinefelter's syndrome.     

Coasting-what is the best formula?

Coasting is a method to decrease the incidence of ovarian hyperstimulation syndrome (OHSS), which involves withdrawing exogenous gonadotrophins until the serum estradiol (E(2)) level decreases. The application of this strategy, as it appears in the literature, has been variable, with heterogeneous criteria for initiating and ending the coasting process and as a result, reports of efficacy are inconsistent. In attempt to establish a recommended protocol for coasting we reviewed and analysed 10 relevant studies, found by a Medline search. Based on the data collected, coasting should be initiated when the serum E(2) concentration exceeds 3000 pg/ml, but not unless the leading follicles reach a diameter of 15-18 mm. Its duration should be limited to <4 days, thus, preventing the decrease in implantation and pregnancy rates that occur after longer periods of coasting. Administration of hCG should be withheld until serum E(2) falls below 3000 pg/ml. Based on the published data, these suggested guidelines result in an acceptably low incidence of severe OHSS (<2%) and provide satisfactory fertilization and pregnancy rates (55-71% and 36.5-63% respectively). A multicentre randomized prospective study would help to confirm the effectiveness of this approach.     

Induction of ovulation after gnRH antagonists

The gonadotrophin-releasing hormone (GnRH) antagonist binds competitively to the receptors and thereby prevents endogenous GnRH from exerting its stimulatory effect on the pituitary cells. This causes suppression of gonadotrophin secretion which occurs immediately after administration of the antagonist. When using GnRH antagonist in controlled ovarian stimulation, ovulation or maturation of the oocyte can, therefore, be induced by a variety of drugs, e.g. native GnRH, recombinant LH or short-acting GnRH agonists. Short-acting GnRH agonists were recommended for triggering ovulation in cases with a high risk of developing ovarian hyperstimulation syndrome (OHSS). Since it is evident that GnRH is required to initiate the LH surge and the oestradiol rise, a single administration of GnRH antagonist during the late follicular phase delays the LH surge. Studies showed that a single s.c. administration of 3 or 5 mg of Cetrorelix in the late follicular stage was sufficient to prevent the LH surge for 617 days. This phenomenon can be used in high responder patients who are prone to OHSS. The question whether this delay has any effect on oocyte quality and maturation still remains unanswered. Overall, there are four uses for GnRH antagonist: (i) using short-acting GnRH agonists for triggering ovulation in cases in which the GnRH antagonist is part of the protocol for ovarian stimulation. Recombinant LH and native LHRH could also be used as triggers of LH surge; (ii) delaying the LH surge in cases prone to OHSS by treatment with GnRH antagonist; (iii) to administer GnRH antagonist during the luteal phase to decrease the activity of corpora lutea; (iv) in polycystic ovarian disease with elevated LH the LH/FSH ratio can be corrected with the injection of GnRH antagonist prior to and during ovarian stimulation.     

Monozygotic twinning after assisted reproductive techniques: a phenomenon independent of micromanipulation

A 3 year retrospective analysis was conducted of pregnancies achieved after various assisted reproductive treatment modalities in our infertility practice, to calculate and compare the rates of monozygotic twinning (MZT). A total of 731 pregnancies achieved after various assisted reproduction treatments were reviewed. Gonadotrophin therapy for induction of ovulation and controlled ovarian hyperstimulation (COH) yielded 129 clinical pregnancies. Conventional IVF yielded 139 pregnancies. IVF and intracytoplasmic sperm injection (ICSI) with or without assisted hatching (AH) yielded 463 pregnancies, all during the same time period. The rates of multiple pregnancy (monozygotic and dizygotic) twins and triplets were recorded. MZT was found in 1.5% of ovulation induction or COH pregnancies (2/129). The incidence of MZT after conventional IVF was 0.72% (1/139). After IVF-ICSI/AH, MZT was found in 0.86% (4/463). The overall rate of MZT was 0.95% (7/731). Five cases were dizygotic triplets and two cases were monozygotic twins. We found the rate of MZT after assisted reproduction treatment increased more than two-fold over the background rate in the general population. Dizygotic triplets were found more often than monozygotic twins. The rate of MZT was consistently increased, irrespective of treatment modality or micromanipulation. This may signify that the aetiology of increased MZT after assisted reproduction is the gonadotrophin treatment rather than in-vitro conditions, micromanipulation, or multiple embryo transfer.     

Intracytoplasmic injection of fresh and cryopreserved testicular spermatozoa in patients with nonobstructive azoospermia—a comparative study

Objective: To compare the outcome of intracytoplasmic sperm injection (ICSI) with fresh and frozen-thawed testicular spermatozoa in patients with nonobstructive azoospermia.Design: Retrospective analysis of consecutive ICSI cycles.Setting: In Vitro Fertilization Unit, Assaf Harofeh Medical Center.Patient(s): Eighteen with nonobstructive azoospermia in whom testicular sperm was found after testicular sperm extraction.Intervention(s): Testicular sperm retrieval, cryopreservation, and ICSI with fresh or frozenthawed testicular spermatozoa.Main Outcome Measure(s): Two-pronuclear fertilization; embryo cleavage rates, mean number of embryos transferred per cycle, and their relative quality, embryo implantation, clinical pregnancy, and ongoing pregnancy rates (PRs) per ET.Result(s): No statistically significant differences were noted in all parameters examined between ICSI cycles with fresh or cryopreserved testicular spermatozoa from the same nine patients and comparing all ICSI cycles performed; with fresh (25 cycles) and thawed (14 cycles) testicular spermatozoa, respectively: two-pronuclear fertilization, 47% versus 44%; embryo cleavage rates, 94% versus 89%; implantation rates, 9% versus 11%; and clinical PR, 26% versus 27%. The delivery or ongoing PR using fresh sperm was better (21% versus 9%), but the difference did not reach statistical significance. The cumulative clinical PRs and ongoing PRs per testicular sperm extraction procedure were 36% and 24%, respectively.Conclusion(s): Testicular sperm cryopreservation using a simple freezing protocol is promising in patients with nonobstructive azoospermia augmenting the overall success achieved after surgical sperm retrieval. (Fertility Sterility 1997;68:892-7. C 1997 by American Society for Reproductive Medicine.)     

Simultaneous quantification of isoniazid,rifampicin, ethambutol and pyrazinamide by liquid chromatography/tandem mass spectrometry

A remediable cause of poor treatment response in drug‐susceptible tuberculosis (TB) patients may be low plasma levels of one or more of the first‐line anti‐TB drugs. The aim of this work was to develop an accurate and precise LC‐MS/MS method for simultaneous quantification of all four first‐line anti‐TB drugs in plasma suitable for therapeutic drug monitoring (TDM). To adjust for degradation and losses during sample preparation, isotopically labeled compounds were used as internal standards. Plasma samples spiked with internal standards were extracted using protein precipitation with methanol and acetonitrile. Simultaneous separation of all four drugs was accomplished with a Chromolith Reversed‐Phase column and mobile phases consisting of water, methanol, ammonium acetate and formic acid with subsequent mass spectrometric quantification. The linear range of the calibration curve for isoniazid was 0.5–10 mg/L, for rifampicin 0.75–30 mg/L, for ethambutol 0.25–10 mg/L and for pyrazinamide 4–80 mg/L. The lower limit of quantification was 0.5 mg/L, 0.75 mg/L, 0.25 mg/L and 4.0 mg/L, respectively. Precision estimated by the coefficient of variation was <15% for all four drugs. The LC‐MS/MS method can readily be used for simultaneous quantification of first‐line anti‐TB drugs in plasma and is well suited for TDM.