Identifying twin gestations at low risk for preterm birth with a transvaginal ultrasonographic cervical measurement at 24 to 26 weeks' gestation

OBJECTIVE: Because twins are a high-risk group for preterm birth, many clinicians routinely use prophylactic interventions such as home bed rest, hospital bed rest, oral tocolytics, or home uterine activity monitoring to prevent preterm delivery. We sought to identify twin gestations at low risk for spontaneous preterm birth with transvaginal ultrasonography of the cervix to avoid the unnecessary use of prophylactic interventions in these pregnancies. STUDY DESIGN: We measured cervical length at 24 to 26 weeks' gestation by transvaginal ultrasonography in women with twin gestations referred to our prematurity prevention clinic. Each delivery was classified as (1) spontaneous preterm birth < 34 weeks' gestation, (2) delivery at > or = 34 weeks' gestation with intervention, or (3) delivery at > or = 34 weeks' gestation without intervention. Intervention included strict bed rest at home or in the hospital, either parenteral or oral tocolysis, or both, or home uterine activity monitoring. Indicated preterm deliveries and patients with cerclage were excluded from this analysis. The ability of transvaginal cervical length to predict women who would deliver at > or = 34 weeks without intervention was evaluated. A cervical length of 35 mm was chosen by scatter diagram as the best cutoff to discriminate between the group delivered at term without intervention and the other two groups. RESULTS: Of 85 women with twin gestations who underwent ultrasonographic cervical length measurements at 24 to 26 weeks' gestation, 17 had spontaneous preterm birth at < 34 weeks, 23 were delivered at > or = 34 weeks but required intervention, and 45 were delivered at > or = 34 weeks without intervention. The mean cervical length for those delivered at > or = 34 weeks' gestation without intervention (36.4 +/- 5.8 mm) was significantly greater (p < 0.0001) than the mean for those delivered preterm (27.4 +/- 8.5) and those delivered at > or = 34 weeks' gestation who required intervention (27.7 +/- 10.5 mm). The sensitivity, specificity, and positive and negative predictive values of a cervical length > 35 mm for predicting delivery at > or = 34 weeks' gestation are 49%, 94%, 97%, and 31%, respectively. CONCLUSION: A transvaginal ultrasonographic measurement of the cervix of > 35 mm at 24 to 26 weeks in twin gestations can identify patients who are at low risk for delivery before 34 weeks' gestation.     

Estimation of Fourier coefficients

It is shown that the maximum-likelihood estimation or robust estimation of the Fourier coefficients may be preferable to Fourier transformation if the noise contains outliers or is otherwise not normally distributed. The reason is that, in that case, these estimators produce Fourier coefficient estimates and, therefore, system parameter estimates having a smaller variance     

Procol

PROCOL is an object-oriented language with distributed delegation. It strongly supports concurrency: many objects may be active simultaneously, they execute in parallel unless engaged in communication. An object has exported operations, called Actions. Only one Action can be active at a time, however special interrupt Actions may interrupt regular Actions. Communication is performed via remote procedure call, or via a one-way synchronous message with short-time binding. In communications both client and server can be specified, either by object instance identifiers, or by type. Therefore client-server mappings may be 1-1,n-1, or 1-n, though only 1 message is transferred. PROCOL controls object access by an explicit per-object protocol. This protocol is a specification of the legality and serialization of the interaction between the object and its clients. It also provides for client type checking. The use of protocols in object communication fosters structured, safer and potentially verifiable information exchange between objects. The protocol also plays an important role as a partial interface specification. In addition it acts as a composition rule over client objects, representing relations with the client objects. PROCOL's communication binding is dynamic (run-time); it functions therefore naturally in a distributed, incremental and dynamic object environment. PROCOL also supports constraints, without compromising information hiding. An implementation is available in the form of aC extension.This author is supported by the Dutch Science Organization NWO     

Hydrolytic degradation of oligo(lactic acid): a kinetic and mechanistic study

This study shows that the degradation mechanism and kinetics of monodisperse oligo(lactic acid)s esterified with N-(2-hydroxypropyl)methacrylamide (HPMAm) are strongly influenced by the nature of the chain end. Oligomers with free hydroxyl chain ends degraded predominantly by chain end scission via a backbiting mechanism with a pseudo first-order rate constant k_bb=2.7 h⁻¹ in aqueous buffer (37 °C, pH 7.2). Once the hydroxyl groups were protected by acetylation, random chain scission became the rate limiting step with k_r=0.022 h⁻¹ under the same conditions. Using these rate constants, the theoretical time-resolved degradation profile was calculated for every (intermediate) degradation product and corresponded very well with the experimental results. The rate of formation of HPMAm was independent of the chain length for the acetylated oligomers, while the hydroxyl terminated oligomers with an even number of lactic acid units formed HPMAm more rapidly than oligomers with an odd number of units. The possibility to fine-tune the degradation rate is relevant when applied as e.g. hydrogels for controlled release or tissue engineering materials.     

The Ras/Erk pathway induces primitive endoderm but prevents parietal endoderm differentiation of F9 embryonal carcinoma cells

The formation of parietal endoderm (PE) is one of the first differentiation processes during mouse development and can be studied in vitro using F9 embryonal carcinoma (EC) cells. Treatment of F9 EC cells with retinoic acid (RA) induces differentiation toward primitive endoderm (PrE), while differentiation toward PE is induced by subsequent addition of parathyroid hormone (PTH) or PTH-related peptide (PTHrP). The signal transduction mechanisms involved in this two-step process are largely unclear. We show that the RA-induced differentiation toward PrE is accompanied by a sustained increase in Ras activity and that ectopic expression of oncogenic Ha-Ras is sufficient to induce PrE differentiation. Ras activity subsequently decreases upon PTH-induced differentiation toward PE. This is a necessary event, since expression of oncogenic Ha-Ras in PrE-like cells prevents PTH-induced PE differentiation. Expression of active PKA in PrE-like F9 cells mimics PTH-induced PE differentiation and is again prevented by oncogenic Ha-Ras. The effect of oncogenic Ras on both differentiation steps is abolished by the MEK inhibitor PD98059 and can be mimicked by constitutively active forms of Raf and MEK. In conclusion, our data suggest that activation of the Ras/Erk is sufficient to induce differentiation to PrE and to prevent subsequent differentiation toward PE. Activation of PKA down-regulates Ras activity, resulting in disappearance of this blockade and transmission of signal(s) triggering PE differentiation.     

Uncertainty management: The influence of uncertainty salience on reactions to perceived procedural fairness.

On the basis of fairness heuristic theory, it is argued in this article that people especially need fairness when they are reminded about aspects of their lives that make them uncertain. It is therefore proposed that thinking about uncertainty should make fairness a more important issue to people. The findings of 3 experiments support this line of reasoning: Asking (vs. not asking) participants 2 questions that solicited their thoughts and feelings of being uncertain led to stronger effects of perceived procedural fairness on participants' affective reactions toward the way they were treated. It is argued that these findings suggest that fairness matters to people especially when they are trying to deal with things that make them uncertain. An implication of the current findings therefore may be that fairness is important to people because it gives them an opportunity to manage uncertain aspects of their lives. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Nuclear magnetic resonance analysis of solution conformations in C4-V3 hybrid peptides derived from human immunodeficiency virus (HIV) type 1 gp120: relation to specificity of peptide-induced anti-HIV neutralizing antibodies

Immunogenic peptides containing epitopes of the gp120 C4 and V3 regions from human immunodeficiency virus strains MN and EV91 have been studied by nuclear magnetic resonance and molecular modeling and used as immunogens in rhesus monkeys. The results, combined with those for other peptides, suggest a correlation between solution conformation and immunologic cross-reactivity.     

A view from the family: years after a loved one has died of ovarian cancer

BACKGROUND: Macrosclerotherapy in combination with compression has proven to be safe and effective in the treatment of varicose veins. Local compression is increased by pads, according to Laplace law. Firm rolls of cotton wool are fixed over the course of the entire vein to increase local compression and to reduce complications. Additional compression is given by a combination of a class I (daytime and nighttime) and class II (daytime only) medical compression hosiery. PURPOSE: To evaluate the effectiveness and side effects of sclerocompression therapy with cotton wool rolls in combination with medical compression hosiery. METHOD: Prospective study with 100 patients (120 legs) with primary varicose veins, which are treated with polidocanol as sclerosant with the empty vein technique. Immediately after the injection, a long cotton wool roll is placed over the entire vein and fixed. Additional compression is obtained with class I and class II medical compression hosiery. The interface pressure on the skin, just under the cotton wool roll, is measured on 12 legs with the aid of an interface pressure measuring instrument (Oxford Pressure Monitor). RESULTS: Good sclerosing results are obtained in all patients. Side effects are classified as early and late. In 16 patients, minor side effects which needed no treatment are observed. In only 3 cases (2.5%), intravascular blood clots (2) and phlebitis (1) needed incision and expression. The mean interface pressure of all measuring sensors under the cotton wool roll is 84 mm/Hg (68 to 122 mm/Hg). CONCLUSION: This study proves the high effectiveness of a cotton wool roll compression right at the place of treatment. By using these long cotton wool compression rolls, the compression part of sclerocompression therapy becomes more effective and much easier to perform.