Preparation methods to optimize the performance of sensor discs for fast chemiluminescence ozone analyzers.

Fast ozone (O(3)) measurements (1-50 Hz) in the atmosphere are required for airborne studies and for the measurement of ground-based O(3) fluxes by the eddy covariance technique. Fast response analyzers, based on heterogeneous chemiluminescence, need dye coated sensor discs on which the chemiluminescence is generated. In this study, we present three new preparation methods for those sensor discs. Currently available sensor discs exhibit a fast temporal decay of sensitivity, resulting in short duty times which is troublesome for many field applications. To produce sensor discs that provide more stable signals over time, three dyes and nine energy transfer reagents were tested (as well as different stoichiometric mixtures). The resulting optimal method saves 80% of the solid chemicals and shows a duty ozone dose that is prolonged by a factor of 3.5, revealing the same average sensitivity as currently available discs. In addition, we observed a strong effect of the adsorption matrix on the O(3) sensitivity, although silica discs from the same manufacturer were used. Application of the new sensor discs during field measurements showed that the results are consistent with the laboratory data.

Measurement of blood volume after haemodilution with haemoglobin-based oxygen carriers by a radiolabelled-albumin method.

Recent studies have shown that the use of haemoglobin-based oxygen-carrying solutions (HBOCs) for perioperative haemodilution could significantly reduce the need for packed red blood cells in clinical practice. Though the effects of HBOCs on plasma volume have been characterized in experimental models of volume resuscitation from hypovolaemic shock, little is known about their action in normovolaemic haemodilution conditions. We therefore applied a radiolabelled serumalbumin method to determine blood volume after haemodilution with crosslinked or conjugated haemoglobin, in comparison with a reference solution of hydroxyethyl starch (HES). Three groups of New Zealand white rabbits were studied (n = 7 each group) subjected to moderate exchange transfusion with low molecular weight HES, bis(3,5-dibromosalicyl)fumarate crosslinked haemoglobin (alphaalpha-Hb), or dextran-conjugated haemoglobin (Hb-Dex-BTC). HES induced no changes in heart rate and blood pressure. The amplitude and duration of blood pressure increase and bradycardia were similar in both haemoglobin groups. A significant contraction of blood volume (12%) was observed 60 min after haemodilution with alphaalpha-Hb, compared to HES and Hb-Dex-BTC. At the same time point, a decrease in absolute haemoglobin (plasma haemoglobin x plasma volume) was also noted. This study suggests that in haemodilution conditions, the specific oncotic properties and circulating persistence of crosslinked and conjugated haemoglobin solutions affect the pattern of blood volume distribution differently.

Ultrasound-guided injection of ectopic pregnancy.

Preliminary studies have demonstrated that salpingocentesis is a safe and effective treatment for unruptured ectopic pregnancies that are visible by transvaginal ultrasound. So far, experience with this technique has been confined to only a few centers around the world. The most promising results of these studies has been the virtual absence of side effects associated with local injection of either methotrexate or hyperosmolar glucose. Large prospective trials comparing efficacy, safety, and overall cost of salpingocentesis against systemic methotrexate will be necessary to better define the role of salpingocentesis in the management of ectopic pregnancy. Patient recruitment for this type of clinical trial would be feasible and acceptable to patients because both treatment arms would avoid surgery.

Gamete intrafallopian transfer. Comparison of epidural vs. general anesthesia.

OBJECTIVE: To investigate the reproductive outcome of laparoscopic gamete intrafallopian transfer (GIFT) performed under epidural vs. general anesthesia. STUDY DESIGN: Retrospective analysis of 110 consecutive laparoscopic GIFT procedures performed under general or epidural anesthesia. All patients underwent controlled ovarian hyperstimulation employing human menopausal gonadotropin and gonadotropin releasing hormone agonist, given either in the midluteal or early follicular phase. Data were retrieved concerning age, diagnosis, estradiol levels and maximum follicular diameter at the time of human chorionic gonadotropin injection, percentage of mature oocytes retrieved and number of oocytes transferred. These variables were compared using the independent means t test. Pregnancy rates and outcome between the general and epidural anesthesia groups were compared with the chi 2 test. RESULTS: Of the 110 procedures, 84 were performed under general anesthesia, whereas 22 were done using epidural anesthesia. Four procedures started with epidural anesthesia and were converted to general anesthesia because of upper abdominal discomfort. The success rate of epidural anesthesia, therefore, was 85% (22/26). There were no significant differences in the confounding variables between the general and epidural anesthesia groups. However, patients receiving epidural anesthesia had a significantly higher pregnancy rate, 59.1%, and a live birth rate of 40.9% as compared to 31.0% and 21.4%, respectively, for the general anesthesia group. CONCLUSION: Laparoscopic GIFT can be performed safely under epidural anesthesia. Because of the higher pregnancy and live birth rates, epidural is the anesthetic of choice for GIFT. However, a prospective, randomized study is needed to confirm the above observation.

Gamete intrafallopian transfer. Does smoking play a role?

OBJECTIVE: To investigate the effects of active and passive cigarette smoking on the outcome of gamete intrafallopian transfer (GIFT). STUDY DESIGN: A retrospective analysis of 98 patients who had laparoscopic GIFT was performed. Data were retrieved concerning age, diagnosis, amount of human menopausal gonadotropins (hMG) used for controlled ovarian hyperstimulation (COH), and number of oocytes retrieved and transferred. A detailed smoking history, if any, of patients and household members was obtained from chart review and an additional telephone survey. Pregnancy rates and outcome in active and passive smokers were compared to those of non-smokers. RESULTS: No difference was observed among active smokers (n = 19), passive smokers (n = 13) or nonsmokers (n = 66) regarding diagnosis, age percentage of mature oocytes retrieved or number of oocytes transferred during GIFT. However, active, but nor passive, smokers consumed a higher amount of hMG for COH as compared to nonsmokers. More important, pregnancy and live birth rates for active smokers (15.8% and 10.5%, respectively) were significantly lower than those for passive smokers (46.2% and 23.1%) and nonsmokers (45.5% and 33.3%). No difference, however, was noted between the latter two groups. CONCLUSION: Our results show that active, but not passive, smoking has a negative impact on GIFT pregnancy rates and outcomes. It is important to counsel patients against cigarette smoking prior to GIFT, but whether smoking cessation will improve the outcome needs further study.

Atrial natriuretic peptide, oestradiol and progesterone in women undergoing spontaneous and gonadotrophin-stimulated ovulatory cycles.

The objective of this study was to examine the relationship between the concentrations of oestradiol and progesterone on the one hand and atrial natriuretic peptide (ANP) concentrations on the other, during the follicular and luteal phases of spontaneous and gonadotrophin-stimulated ovulatory menstrual cycles. A total of 27 ovulatory women undergoing either a spontaneous (n = 9) or a gonadotrophin-stimulated (n = 18) cycle were selected for inclusion in this study. In comparison with spontaneous cycles, gonadotrophin-stimulated cycles had increased peak follicular oestradiol (mean +/- SE; 937 +/- 150 versus 195 +/- 18 pg/ml; P < 0.05) and midluteal progesterone (mean +/- SE; 44.0 +/- 7.4 versus 14.1 +/- 2.4 ng/ml; P < 0.05) concentrations. There were no differences in the circulating ANP concentrations between the follicular and luteal phases of the menstrual cycle. Despite the increased oestradiol and progesterone concentrations following gonadotrophin stimulation, no difference in ANP concentrations was seen between stimulated and spontaneous cycles. There was no correlation between circulating concentrations of oestradiol, progesterone (at physiological and supraphysiological concentrations) and ANP throughout the menstrual cycle.

Assisted fertility using electroejaculation in men with spinal cord injury--a review of literature.

OBJECTIVE: To review the effectiveness of rectal probe electroejaculation in terms of pregnancy in treatment of anejaculatory males due to spinal cord injury. The characteristics of electroejaculates also are examined. DATA IDENTIFICATION: All English language studies reporting pregnancies as a result of electroejaculation from men with spinal cord injury and related publications on electroejaculation were identified through MEDLINE search and manual scanning of recent relevant journals. RESULTS: Electroejaculation has become an accepted mode of semen procurement in anejaculatory individuals, with a success rate of approximately 60% to 90% varying among different centers. In general these electroejaculates exhibit high sperm counts but low motility and poor sperm function. Retrograde ejaculation is also common. Pregnancies using electroejaculates have been documented since 1975 in the form of case reports and small series. Assisted reproductive technology recently has been used in conjunction with electroejaculation. Although results are encouraging, pregnancy rates, however, cannot be accurately estimated because of the lack of large series in the literature. CONCLUSIONS: An increasing number of spinal cord-injured patients desiring fertility can achieve pregnancy through combined use of electroejaculation and assisted reproductive techniques. Larger series are needed to establish an accurate pregnancy rate. Elucidation by further studies on etiology of sperm dysfunction of these individuals may improve their prognosis.

A prospective series of unruptured ectopic pregnancies treated by tubal injection with hyperosmolar glucose.

OBJECTIVE: To evaluate the safety and efficacy of hyperosmolar glucose injection in select unruptured tubal gestations with hCG levels less than 2500 mIU/mL. METHODS: In this prospective series, 16 patients with an hCG titer less than 2500 mIU/mL and an unruptured ectopic pregnancy were treated by tubal injection with hyperosmolar (50%) glucose. Hyperosmolar glucose was injected transabdominally into the antimesenteric site of the tubal pregnancy, using a 20-gauge spinal needle. The main outcome measures evaluated were duration of surgery, success rate, time to resolution, and follow-up tubal patency rates. RESULTS: Ninety-four percent (15) of the subjects were treated successfully with a median time to resolution of 24 days (range 5-78). The one treatment failure required methotrexate because of rising hCG titers and worsening pain 4 days after the patient was treated with hyperosmolar glucose. The mean (+/- standard error) duration of surgery was 45 +/- 6 minutes. So far, all ten patients undergoing postoperative hysterosalpingograms have demonstrated tubal patency in the treated tube. CONCLUSION: Laparoscopic injection with hyperosmolar glucose is an effective, systemically nontoxic alternative treatment for select unruptured ectopic pregnancies (hCG less than 2500 mIU/mL) that achieves tubal patency rates comparable to other conservative medical and surgical treatments.

Reproducibility of image interpretation in immunoscintigraphy performed with indium-111- and iodine-131-labeled OC125 F(ab')2 antibody injected into the same patients.

An important criterion for the clinical use of a new imaging technique is the correct reproducibility of interpretation. Forty-six paired immunoscintigraphic examinations were performed on 43 patients with suspected ovarian carcinoma recurrence using F(ab')2 fragments of OC125 antibody labeled first with indium-111 and then with iodine-131. Planar scintigraphy (PS) and emission computed tomography (ECT) images were interpreted blindly and separately by three observers, and reproducibility was evaluated by a kappa concordance index. Intra- and interobserver reproducibility were generally satisfactory (kappa values of 0.6 and 0.7, respectively). Binomial analysis of kappa values for ECT showed the superiority of indium-111 for intraobserver (p = 0.035) and interobserver (p = 0.0039) study. However, for PS there was no significant difference in reproducibility with the two radionuclides.