Management of subsequent pregnancy after an unexplained stillbirth.

PURPOSE: To review the management of pregnancy after an unexplained stillbirth. EPIDEMIOLOGY: Approximately 1 in 200 pregnancies will end in stillbirth, of which about one-third will remain unexplained. Unexplained stillbirth is the largest single contributor to perinatal mortality. Subsequent pregnancies do not appear to have an increased risk of stillbirth, but are characterized by increased rates of intervention (induction of labor, elective cesarean section) and iatrogenic adverse outcomes (low birth weight, prematurity, emergency cesarean section and post-partum hemorrhage). CONCLUSIONS: There is no level-one evidence to guide management in this situation. Pre-pregnancy counseling is very important to detect and correct potential risk factors such as obesity, smoking and maternal disease. As timely delivery is the mainstay of management, early accurate determination of gestational age is vital. There is controversy regarding the pattern of surveillance, but evidence exists only for ultrasound and not for regular non-stress testing, nor formal fetal movement charting. There is an urgent need for more studies in this important area.

Does exogenous coenzyme Q10 affect aerobic capacity in endurance athletes?

The effect of orally supplemented coenzyme Q10 (CoQ10) on plasma CoQ10 concentration and aerobic capacity in endurance athletes was evaluated. Eighteen volunteer male road cyclists and triathletes, 8 in a CoQ10 supplementation group (QG) and 10 in a placebo group (PG), successfully completed the experimental protocol. Subjects were evaluated during and following graded cycling exercise tests, which were performed before and after 28 days of supplementation with 1 mg.kg-1.day-1 of CoQ10 or placebo. The presupplementation plasma CoQ10 concentration was significantly increased from 0.91 +/- 0.13 microgram.ml-1 to 1.97 +/- 0.27 microgram.ml-1 in QG following supplementation (p < .05). However, the CoQ10 supplementation regime had no consistently significant effect on oxygen uptake, anaerobic and respiratory compensation thresholds, blood lactate, glucose and triglyceride kinetics, heart rate, and blood pressure during and after graded cycling to exhaustion.

Correlations between short-course triathlon performance and physiological variables determined in laboratory cycle and treadmill tests.

The aim of this study was to investigate the relationships between physiological variables measured in graded cycling (CM) and treadmill running (RM) maximal tests and the performance of a short-course triathlon (1 km swim, 30 km cycling and 8 km running) in recreational triathletes. Ten male athletes with mean (+/-SD) age of 27.4(+/-5.7) years and maximal oxygen consumption (VO2peak) of 63.3(+/-8.95) mL.kg-1.min-1 participated in the study. The results showed that the VO2peak and VO2 at ventilatory threshold (VO2VT) determined in CM were significantly correlated to the overall and running times of the triathlon (r = -0.64 - 0.77, p < or = 0.05). The VO2peak and VO2VT determined in RM were also correlated to the running time when expressed as mL.kg-1.min-1 (r = -0.73, p < or = 0.05). The VT expressed as %VO2peak in both tests showed no significant correlations to triathlon performance. It appears that it is the absolute aerobic capacity of these athletes being critical to maintain a high exercise intensity in the triathlon, especially during the running segment. The mean heart rate (HR) measured in four subjects during the cycling and running segments of the triathlon was similar to the HR at VT determined in CM, which indicated that these athletes could maintain an exercise intensity close to the VT level during the competition. There was no significant correlation found between the swimming time and physiological variables measured in the laboratory cycling and running tests, which could be explained by the specific skills and economy of movement required in these exercises.

Undiagnosed ectopic pregnancy: a retrospective analysis of 31 'missed' ectopic pregnancies at a teaching hospital.

The management of 255 surgically proven cases of ectopic pregnancy, treated at a teaching hospital over a 5-year period, was retrospectively reviewed to determine the proportion of cases where the diagnosis was 'missed' at initial presentation. Thirty-one patients (12%) had presented and been discharged with an incorrect diagnosis, then subsequently readmitted for definite treatment of a tubal ectopic pregnancy. In this group, the mean time from initial presentation to definitive surgery was 8 days. Ten of the 31 women with 'missed' ectopic pregnancies (32%) underwent salpingectomy, whereas the rate of salpingectomy in those women whose ectopic pregnancy was correctly diagnosed at first presentation was 19.5% (44 of 224). We conclude that delays in the diagnosis of ectopic pregnancy may be associated with an increased rate of salpingectomy, which may in turn reduce prospects for future fertility, a finding not previously canvassed in the literature. The factors contributing to misdiagnosis of ectopic pregnancy are discussed and compared with those reported in other studies.

Expression and distribution of microtubule proteins in neurites of dorsal root ganglion neurons in culture.

The expression and distribution of ß-tubulin gene products and post-translationally modified forms of α-tubulin in dorsal root ganglion neurons in culture were examined. The neurons in culture rapidly regenerated neurites and expressed multiple ß-tubulin genes (Mß2, Mß3/4, Mß5, Mß6). The gene products were present in the neurites and growth cones. Unmodified tyrosinated α-tubulin was present in the neurites and growth cones but modified α-tubulins (detyrosinated and acetylated) were largely absent from growth cones. The distribution of the α-tubulin forms is consistent with assembly of tubulin occurring behind the growth cone after transport of non-polymeric subunits. Distal assembly of microtubules would provide a pool of unmodified α-tubulin subunits for the assembly of labile microtubules in the growth cone. Subsequent modification behind the advancing growth cone would stabilise the newly formed neurite.

L-type calcium channels in the regulation of neurite outgrowth from rat dorsal root ganglion neurons in culture.

Dorsal root ganglion neurons from neonatal rats were grown in culture for 12 h and the extent of neurite outgrowth determined by counting the fraction of neurons with neurites. In the presence of high K+, veratridine or bradykinin the extent of neurite outgrowth was reduced by about 60%. The inhibitory effect of depolarisation was reversible and was abolished by nifedipine. gamma-Aminobutyric acid (GABA), baclofen and 2-chloroadenosine had no effect on neurite outgrowth in control cultures but abolished the inhibitory effect of depolarisation.

Differential localisation of tyrosinated, detyrosinated, and acetylated alpha-tubulins in neurites and growth cones of dorsal root ganglion neurons.

The comparative distribution of tyrosinated, detyrosinated, and acetylated alpha-tubulins was examined in neurites of rat dorsal root ganglion neurones in culture using immunofluorescence microscopy. Phase contrast observations of single neurones revealed that the neurites were actively motile, and rhodamine phalloidin staining of actin filaments showed the extent of lamellopodia and microspike projections from the growth cones. From double-labelling experiments using antibodies against tyrosinated, detryrosinated, or acetylated alpha-tubulin, it was found that the three different isoforms were differentially localised in neurites and growth cones. Detyrosinated and acetylated forms of alpha-tubulin were in the main restricted to the neurites extending no further than the base of the growth cones. Tyrosinated alpha-tubulin was, however, distributed throughout the body of the growth cone and into the base of some microspikes. Following treatment with taxol to promote microtubule assembly, detyrosinated and acetylated alpha-tubulins were found to be colocalised with tyrosinated alpha-tubulins throughout the growth cones of all cells examined. These results would be consistent with axonal transport of tyrosinated alpha-tubulin followed by assembly in the growth cone and subsequent detyrosination and acetylation. In addition the presence of unmodified alpha-tubulin in the growth cone may be necessary for the provision of labile microtubules for growth cone motility and extension.

Colocalisation of acetylated microtubules, glial filaments, and mitochondria in astrocytes in vitro.

We have recently shown that acetylated alpha-tubulin containing microtubules (acetyl-MTs; labeled by antibody 6-11B-1) constitute a cold-stable subset of the microtubule network of nonneuronal cells in rat primary forebrain cultures [Cambray-Deakin and Burgoyne: Cell Motil. 8(3):284-291, 1987b]. In contrast, tyrosinated alpha-tubulin containing MTs (tyr-MTs; labeled by antibody YL1/2) are cold-labile. Here we have examined the distribution of acetyl-MTs and tyr-MTs in cultures of newborn rat forebrain astrocytes and simultaneously investigated the distribution of mitochondria and glial filaments. In double-label immunofluorescence experiments a marked colocalisation of acetyl-MTs and glial filament bundles was observed. Tyr-MTs did not show a similar colocalisation with glial filament bundles. Furthermore, the distribution of mitochondria closely followed that of the acetyl-MT and glial filament bundles. When cells were exposed to short-term (30-min) treatments with MT-disrupting agents such as colchicine and nocodazole, the tyr-MT network was removed but the distributions of acetyl-MTs, glial filaments, and mitochondria were unchanged. Increased exposure to colchicine (9-16 hr) caused a progressive disruption of the acetyl-MTs and the collapse of glial filaments and mitochondria to the perinuclear region. These results suggest that acetyl-MTs and glial filaments but not tyr-MTs may be involved in the intracellular transport of organelles and/or in the control of their cytoplasmic distribution.