Development of a single-visit protocol for the management of pregnancy of unknown location following in vitro fertilization: a retrospective study.

STUDY QUESTION: Can women with pregnancy of unknown location (PUL) following in vitro fertilization (IVF) be risk-stratified regarding the subsequent need for medical intervention, based on their demographic characteristics and the results of serum biochemistry at the initial visit? SUMMARY ANSWER: The ratio of serum hCG to number of days from conception (hCG/C) or the initial serum hCG level at ≥5 weeks' gestation could be used to estimate the risk of women presenting with PUL following IVF and needing medical intervention during their follow-up. WHAT IS KNOWN ALREADY: In women with uncertain conception dates presenting with PUL, a single serum hCG measurement cannot be used to predict the final pregnancy outcomes, thus, serial levels are mandatory to establish a correct diagnosis. Serum progesterone levels can help to risk-stratify women at their initial visit but are not accurate in those taking progesterone supplementation, such as women pregnant following IVF. STUDY DESIGN, SIZE, DURATION: This was a retrospective study carried out at two specialist early pregnancy assessment units between May 2008 and January 2021. A total of 224 women met the criteria for inclusion, but 14 women did not complete the follow-up and were excluded from the study. PARTICIPANTS/MATERIALS, SETTING, METHODS: We selected women who had an IVF pregnancy and presented with PUL at ≥5 weeks' gestation. MAIN RESULTS AND THE ROLE OF CHANCE: A total of 30/210 (14.0%, 95% CI 9.9-19.8) women initially diagnosed with PUL required surgical intervention. The hCG/C was significantly higher in the group of women requiring an intervention compared to those who did not (P = 0.003), with an odds ratio of 3.65 (95% CI 1.49-8.89, P = 0.004). A hCG/C <4.0 was associated with a 1.9% risk of intervention, which accounted for 25.7% of the study population. A similar result was obtained by substituting hCG/C <4.0 with an initial hCG level <100 IU/l, which was associated with 2.0% risk of intervention, and accounted for 23.8% of the study population (P > 0.05). LIMITATIONS, REASONS FOR CAUTION: A limitation of our study is that it is retrospective in nature, and as such, we were reliant on existing data. WIDER IMPLICATIONS OF THE FINDINGS: A previous study in women with PUL after spontaneous conception found that a 2% intervention rate was considered low enough to eliminate the need for close follow-up and serial blood tests. Using the same 2% cut-off, a quarter of women with PUL after IVF could also avoid attending for further visits and investigations. STUDY FUNDING/COMPETING INTEREST(S): No external funding was required for this study. No conflicts of interest are required to be declared. TRIAL REGISTRATION NUMBER: N/A.

Impact of severe acute respiratory syndrome coronavirus 2 on ectopic pregnancy management in the United Kingdom: a multicentre observational study.

OBJECTIVE: To describe the impact of coronavirus disease 2019 (COVID-19) on the management of women with ectopic pregnancy. DESIGN: A multicentre observational study comparing outcomes from a prospective cohort during the pandemic [COVID-19-ectopic pregnancy registry (CEPR)] compared with a historical pre-pandemic cohort [non-COVID-19-ectopic pregnancy registry (NCEPR)]. SETTING: Five London university hospitals. POPULATION AND METHODS: Consecutive patients diagnosed clinically and/or radiologically with ectopic pregnancy (March 2020-August 2020) were entered into the CEPR and results were compared with the NCEPR cohort (January 2019-June 2019). An adjusted analysis was performed for potentially confounding variables. MAIN OUTCOME MEASURES: Patient demographics, management (expectant, medical and surgical), length of treatment, number of hospital visits (non-surgical management), length of stay (surgical management) and 30-day complications. RESULTS: Three hundred and forty-one women met the inclusion criteria: 162 CEPR and 179 NCEPR. A significantly lower percentage of women underwent surgical management versus non-surgical management in the CEPR versus NCEPR (58.6%; 95/162 versus 72.6%; 130/179; P = 0.007). Among patients managed with expectant management, the CEPR had a significantly lower mean number of hospital visits compared with NCEPR (3.0, interquartile range [IQR] [3, 5] versus 9.0, [5, 14]; P = <0.001). Among patients managed with medical management, the CEPR had a significantly lower median number of hospital visits versus NCEPR (6.0, [5, 8] versus 9, [6, 10]; P = 0.003). There was no observed difference in complication rates between cohorts. CONCLUSION: Women were found to undergo significantly higher rates of non-surgical management during the COVID-19 first wave compared with a pre-pandemic cohort. Women managed non-surgically in the CPER cohort were also managed with fewer hospital attendances. This did not lead to an increase in observed complication rates. TWEETABLE ABSTRACT: A higher rate of non-surgical management of ectopic pregnancy during the COVID-19 pandemic did not increase complication rates.

Integrin-binding peptides containing RGD produce coronary arteriolar dilation via cyclooxygenase activation.

Integrin binding by Arg-Gly-Asp (RGD)-containing peptides has been shown to alter vascular tone in a variety of blood vessels and has been implicated as a mechanism of vasoregulation during tissue injury. However, the effect of these peptides in the coronary circulation has not been examined. Thus the purpose of our study was to test the hypothesis that integrins act as receptors linked to the regulation of coronary vasomotor function. In particular, the ability of RGD-containing peptides to influence vascular tone by interacting with the alpha(v)beta(3)- and alpha(5)beta(1)-integrins was studied in isolated pig coronary arterioles. All vessels developed basal tone and dilated in a concentration-dependent manner to soluble peptides cyclic GPenGRGDSPCA (cyclic RGD), an alpha(v)beta(3)-cyclic-binding peptide (XJ735), DMP7677, an alpha(5)beta(1)-binding peptide, and to protease-generated (neutrophil elastase) fragments of denatured collagen type I (a major RGD-containing extracellular matrix protein). The vasodilations to cyclic RGD, XJ735, and collagen fragments were almost completely blocked by endothelial removal or by the cyclooxygenase inhibitor indomethacin. In contrast, after endothelial removal and incubation with indomethacin, coronary arterioles showed concentration-dependent constriction to the alpha(5)beta(1)-integrin ligand DMP7677 but not to cyclic RGD or XJ735. Collectively, our results indicate that activation of endothelial alpha(v)beta(3)- and alpha(5)beta(1)-integrins mediates coronary arteriolar dilation via the endothelial production of cyclooxygenase-derived prostaglandins. These data support a role for integrins in the regulation of coronary vascular tone that may be particularly important during myocardial injury.

Alteration of microtubule polymerization modulates arteriolar vasomotor tone.

Microtubules are important cytoskeletal elements that have been shown to play a major role in many cellular processes because of their mechanical properties and/or their participation in various cell signaling pathways. We tested the hypothesis that depolymerization of microtubules would alter vascular smooth muscle (VSM) tone and hence contractile function. In our studies, isolated cremaster arterioles exhibited significant vasoconstriction that developed over a 20- to 40-min period when they were treated with microtubule depolymerizing drugs colchicine (10 microM), nocodazole (10 microM), or demecolcine (10 microM). Immunofluorescent labeling of microtubules in cultured rat VSM revealed that both colchicine and nocodazole caused microtubule depolymerization over a similar time course. The vasoconstriction was maintained over a wide range of intraluminal pressures (30-170 cmH(2)O). The increased tone was not affected by endothelial denudation, suggesting that it was due to an effect on VSM. Microtubule depolymerization with demecolcine or colchicine had no effect on VSM intracellular Ca(2+) concentration ([Ca(2+)](i)). These data indicate that microtubules significantly interact with processes leading to the expression of vasomotor tone. The mechanism responsible for the effect of microtubules on vasomotor tone appears to be independent of both the endothelium and an increase in VSM [Ca(2+)](i).

Modulation of calcium current in arteriolar smooth muscle by alphav beta3 and alpha5 beta1 integrin ligands.

Vasoactive effects of soluble matrix proteins and integrin-binding peptides on arterioles are mediated by alphav beta3 and alpha5 beta1 integrins. To examine the underlying mechanisms, we measured L-type Ca2+ channel current in arteriolar smooth muscle cells in response to integrin ligands. Whole-cell, inward Ba2+ currents were inhibited after application of soluble cyclic RGD peptide, vitronectin (VN), fibronectin (FN), either of two anti-beta3 integrin antibodies, or monovalent beta3 antibody. With VN or beta3 antibody coated onto microbeads and presented as an insoluble ligand, current was also inhibited. In contrast, beads coated with FN or alpha5 antibody produced significant enhancement of current after bead attachment. Soluble alpha5 antibody had no effect on current but blocked the increase in current evoked by FN-coated beads and enhanced current when applied in combination with an appropriate IgG. The data suggest that alphavbeta3 and alpha5 beta1 integrins are differentially linked through intracellular signaling pathways to the L-type Ca2+ channel and thereby alter control of Ca2+ influx in vascular smooth muscle. This would account for the vasoactive effects of integrin ligands on arterioles and provide a potential mechanism for wound recognition during tissue injury.

Role of K+ channels in arteriolar vasodilation mediated by integrin interaction with RGD-containing peptide.

Integrins are transmembrane adhesion receptors found on most cells, including vascular smooth muscle cells. Several integrins bind to the conserved amino acid sequence Arg-Gly-Asp (RGD), and synthetic RGD-containing peptides can cause endothelium-independent arteriolar vasodilation by interacting with the alphavbeta3-integrin expressed by vascular smooth muscle. We hypothesized that RGD peptide-induced vasodilation involves K+ channels. Rat cremaster arterioles were treated with cRGD (GPenGRGDSPCA) in the presence or absence of the nonselective K+ channel inhibitor tetraethylammonium (TEA, 20 mM). TEA caused arterioles to constrict by 19 +/- 5% and inhibited cRGD-induced vasodilation (n = 7, P < 0.05). Vessels preconstricted with phenylephrine (5 x 10(-7) M) showed no significant inhibition of the dilatory response to cRGD, indicating that inhibition by TEA was not related to increased vasomotor tone. Further evidence for the involvement of K+ channels was obtained by addition of 100 mM KCl (n = 5), which inhibited vasodilation caused by cRGD. Inhibition of large and small conductance, Ca2+-activated K+ channels with iberiotoxin (100 nM) or apamin (25 nM), respectively, had no effect on cRGD-induced vasodilation. Partial inhibition of vasodilation was observed with inhibitors of voltage-gated (4-aminopyridine, 1 mM), ATP-sensitive (glibenclamide, 1 microM), and inward rectifying (barium, 50 microM) K+ channels. These data support the hypothesis that integrin-signaling pathways leading to arteriolar vasodilation may involve modulation of K+ channel function.

Vascular smooth muscle alpha v beta 3 integrin mediates arteriolar vasodilation in response to RGD peptides.

Arteriolar vasodilation and the resultant increase in blood flow are characteristic vascular responses to tissue injury. The dilatory mediators signaling these responses are incompletely understood. We show that integrin-binding peptides containing the Arg-Gly-Asp (RGD) tripeptide sequence cause immediate and, in some instances, sustained vasodilation when applied to isolated rat cremaster arterioles. The vasodilation is dependent on interaction of the soluble RGD sequence with the alpha v beta 3 integrin expressed by smooth muscle cells in the arteriolar wall. Possible in vivo sources of soluble RGD sequences are fragments of extracellular matrix proteins that are generated after tissue injury. Indeed, protease-generated fragments of denatured collagen type I (a major source of RGD sequences) also cause cremaster arteriolar vasodilation through the alpha v beta 3 integrin. Thus, extracellular matrix protein fragments containing the RGD sequence may act as vascular wound recognition signals to regulate blood flow to injured tissue.

Early scintigraphic detection of experimental myocardial infarction in dogs with technetium-99m-glucaric acid.

Recent data have generated some interest in technetium-99m-(99mTc) glucaric acid as an in vivo viability marker. We studied 99mTc-glucaric acid retention in canine models of myocardial ischemia (20-min occlusion of the LAD/40-min reperfusion), acute myocardial infarction (MI) (90-min LAD occlusion/3-hr reperfusion), and chronic MI (90-min occlusion and either 48-hr or 10-day reperfusion). Regional myocardial blood flow was measured by radiolabeled microspheres. No preferential uptake of glucaric acid was observed in ischemic but viable myocardium. The compound showed high affinity for necrotic myocardial tissue for several days following injury. The preferential uptake in infarcted tissue disappeared by 10 days following injury. This study shows that 99mTc-glucaric acid acts exclusively as a marker of necrosis in canine models of MI. Technetium-99m-glucaric acid may have clinical utility in early cardiac imaging of myocardial infarction and in differentiating recent from old injuries.

Regional cerebral blood flow and distribution of [99mTc]ethyl cysteinate dimer in nonhuman primates.

Increases in regional cerebral blood flow have been described in a variety of cerebral pathologic states, including stroke and seizure disorders. The usefulness of technetium-99m-labeled cysteinate dimer as a marker in the measurement of regional cerebral blood flow was tested in five cynomolgus monkeys. To expand the range of blood flow to beyond the normal limits, 40 mg/kg i.v. of the carbonic anhydrase inhibitor acetazolamide was administered. Regional cerebral blood flow in all five monkeys was measured using radiolabeled microspheres (before and after acetazolamide) and the marker (after acetazolamide) in 60-70 samples from 12 brain regions. Acetazolamide significantly increased the mean +/- SEM regional cerebral blood flow measured using microspheres from 0.56 +/- 0.21 to 1.71 +/- 0.9 ml/min/g (p less than 0.01 for each region). A significant positive correlation was found between regional cerebral blood flow values calculated using microspheres and the marker after normalizing the values to those in the cerebellum (r = 0.773, p less than 0.0001). The mean +/- SEM regional cerebral blood flow determined using the marker in a single monkey (1.21 +/- 0.04 ml/min/g) did not differ significantly from that determined in the same monkey using microspheres (1.13 +/- 0.04 ml/min/g). These data support the potential use of this new brain perfusion imaging agent to assess regional cerebral blood flow over a clinically relevant range of blood flows.