The accuracy of serum chlamydial antibodies in the diagnosis of tubal pathology: a meta-analysis

Objective: To assess the discriminative capacity of Chlamydia antibody titers in the diagnosis of tubal pathology in subfertile patients.

Design: Meta-analysis of studies comparing Chlamydia antibody titers and laparoscopy for tubal patency and peritubal adhesions.

Patients: A total of 2,729 patients with subfertility in 23 studies.

Intervention(s): Chlamydia antibody titer and laparoscopy as part of subfertility work-up.

Main Outcome Measure: Sensitivity and specificity of Chlamydia antibody titers in the diagnosis of tubal pathology using laparoscopy with chromopertubation as the reference standard.

Result(s): The discriminative capacity of Chlamydia antibody titers depended on the type of assay that was used. Summary receiver operating characteristic (ROC) curves of studies using ELISA or (micro)immunofluorescence revealed a better discrimination than the summary ROC-curve of studies using immunoperoxidase assay.

Conclusion(s): The discriminative capacity of Chlamydia antibody titers by means of ELISA, microimmunofluorescence, or immunofluorescence in the diagnosis of any tubal pathology is comparable to that of hysterosalpingography (HSG) in the diagnosis of tubal occlusion. Chlamydia antibody testing involves little burden but provides no details on the anatomy of uterus and tubes. Whether or not Chlamydia antibody testing can replace HSG depends on the perspective taken in the diagnostic work-up of subfertility.     

High frequency ventilation

The 1990s have seen a dramatic resurgence of interest in high frequency ventilation (HFV). The role of HFV in the rescue of infants failing conventional mechanical ventilation (CMV) is now relatively well established. However, the wider role of HFV in the routine management of respiratory failure in the newborn is more contentious. Recent trials in small numbers of infants suggest that HFV may be associated with significantly less chronic lung disease than CMV when used under optimal conditions (i.e. with a 'high-volume' strategy, from early in the disease and continued to the point of weaning). Further, clinical trials are now required to define the role of HFV more clearly.     

Endocrinology: Progesterone alone versus progesterone combined with HCG as luteal support in GnRHa/HMG induced IVF cycles: a randomized clinical trial

Two different regimens of luteal support in gonadotrophin hormone-releasinghormone (GnRH) analoguefhuman menopausal gonadotrophin (GnRHa/HMG)-inducedin-vitro fertilization cycles (IVF) were compared in a randomizedclinical trial. After embryo transfer, either vaginal progesteronealone was administered (n=89, P group), or a combination ofvaginal progesterone and human chorionic gonadotrophin (n=87,P/HCG group). The primary aim of this study was to assess theeffect of the different regimens of luteal support on the pregnancyrate. The secondary aim was to compare oestradiol and progesteroneconcentrations in the luteal phase between the two groups, andassess their effect on the pregnancy rate. A clinical pregnancyrate of 15% was found in the P/HCG group in comparison with26% in the P group (odds ratio 0.49; 99% confidence interval:0.18–1.3). The luteal serum oestradiol and progesteronevalues in the P/HCG group were significantly higher when comparedwith the P group on the 6th, 9th and 12th day after oocyte retrieval(Wilcoxon P<0.001). In accordance with the high oestradiolconcentrations, more cases of ovarian hyperstimulation syndrome(OHSS) were found in the P/HCG group. Oestradiol values on the9th day after oocyte retrieval, presumably the day of implantation,appeared to be higher in women who did not become clinicallypregnant. We conclude that vaginal progesterone alone providessufficient luteal support in GnRHa/HMG induced IVF cycles. Thecombination of vaginal progesterone and HCG as luteal supportleads to significant high luteal oestradiol and progesteroneconcentrations. But a high concentration of oestradiol seemsto have a deleterious effect on the implantation process, resultingin a low pregnancy rate.     

Angular deformity of the lower extremity: evaluation with quantitative bone scintigraphy. Work in progress

A technique for quantitative analysis of growth plates in varus or valgus deformity about the knee has been developed. Computer-generated regions of interest are placed on magnification scintigraphs to divide distal femoral and proximal tibial physes into four equal segments. The ratio of counts in the medial half to counts in the lateral half was studied in 34 children (23 healthy, 11 with angular deformity). Normal ratios were 0.74-0.98 for femurs and 0.98-1.20 for tibias. An above-normal ratio correlated with the presence of valgus deformity and a below-normal ratio with varus deformity. This technique may provide a means of monitoring growth after trauma or infection.     

Increased contractile potential of papillary muscles from exercise-trained rat hearts

Female rats (n = 24) swam 6 h/day, 5 days/wk, for over 6 wk. Training increased both wet and dry weight of ventricles 15% above control. The active length-tension curve for trained left ventricular papillary muscles (LVPM) was elevated, with maximum tension (Tmax) at optimal length 37% higher than that of untrained LVPM. Training did not alter passive length-tension, time-to-peak tension (TPT), or half-relaxation time (1/2RT). The maximum rate of tension development (dT/dt), however, was increased 22% by training. The force-velocity curve of trained LVPM was shifted upward; both estimated Vmax and the minimum isometric load where shortening equals zero were greater than control. Exogenous isoproterenol (5.8 nM) did not affect Tmax but significantly decreased TPT and 1/2RT to the same extent for both groups of muscles. Maximum dT/dt was increased to a greater extent by isoproterenol for trained LVPM. These findings indicate hearts hypertrophied by exercise have an increased contractile potential per unit of myocardial mass.     

Mechanisms for the hepatic uptake of organic cations. Studies with the muscle relaxant vecuronium in isolated rat hepatocytes

In hepatobiliary transport of organic cations some remarkable differences have been reported between the monovalent compounds (prototype procainamidethobromide) and the potentially bivalent cations, containing a second quaternary ammonium group or a protonated tertiary amine function (prototype d-tubocurarine). In order to characterize the hepatic uptake mechanism for such bivalent cations in more detail, we studied the uptake of the steroidal muscle relaxant vecuronium in isolated rat hepatocytes. Uptake occurred by both a saturable (Vmax = 181 pmol/min x 10(6) cells, Km = 15 microM) and a nonsaturable process (rate constant = 1.10 pmol/min/10(6) cells/microM). The uptake of vecuronium was reduced by various metabolic inhibitors and by sulfhydryl-blocking agents. The transport system showed temperature dependency with an activation energy of 85 kJ/mol. Sodium replacement by lithium or choline in the extracellular medium had no effect on the uptake of vecuronium. Replacement of sodium chloride by sucrose led to a decrease of the uptake, whereas chloride replacement by bicarbonate or iodide stimulated the vecuronium uptake. These data point to a significant anion-dependency of the uptake system and indicate electroneutral uptake of vecuronium. The uptake of vecuronium was inhibited by a variety of hepatic transport model compounds, including bile acids, uncharged compounds and high molecular weight organic cations. Low molecular weight monovalent cations had no effect on the uptake of vecuronium.(ABSTRACT TRUNCATED AT 250 WORDS)     

PET detection of viable tissue in myocardial segments with persistent defects at T1-201 SPECT

To assess myocardial glucose metabolism and perfusion in 142 myocardial segments with defects seen at thallium-201 single photon emission computed tomography (SPECT), 27 studies with positron emission tomography (PET) utilizing nitrogen-13 ammonia and fluorine-18 deoxyglucose were performed in 26 patients. Myocardial infarction was defined on the basis of concordant reductions in segmental perfusion and glucose utilization; myocardial ischemia, on the basis of preservation of glucose utilization (metabolic viability) in segments with hypoperfusion at rest. Of the 142 segments analyzed, 101 had fixed defects, 31 had partially reversible defects, and ten had completely reversible defects. Preserved glucose utilization was identified in 47 (46.5%) of the segments with fixed defects and 20 (64.5%) of the segments with partially reversible defects. Of the ten segments with completely reversible defects, five (50%) were normal, and five (50%) exhibited ischemia at PET. Visual improvement in a persistent thallium defect at delayed imaging was not associated with residual glucose metabolic activity. Thus, PET can be used to detect glucose metabolic activity in a significant proportion of myocardial segments with fixed or partially redistributing defects seen at thallium SPECT, which suggests that the extent of tissue viability in patients with ischemic heart disease is underestimated at thallium scintigraphy.