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Alex C Vidaeff

Publications and source records attributed to Alex C Vidaeff.

At least 19 recordsLinked to original sources
PubMed2006

From concept to practice: the recent history of preterm delivery prevention. Part I: cervical competence.

The prevention of preterm delivery (PTD) is a major desiderate in contemporary obstetrics and a societal necessity. The means to achieve this goal remain elusive, and the research efforts have been punctuated by several ineffective intervention proposals. More recently, new areas of proposed preventive strategy have arisen, focusing on cervical competence, subclinical infection, and hormonal effects. This review, based on a comprehensive and unbiased review of the available literature, will address the rationale and current status of these new concepts of significant clinical interest. We will describe the microcosm of thought and research dedicated to the prevention of PTD during the last 10 years, and the arduous efforts to establish a linkage between predictive observations and therapeutic hypotheses. In its first part, the review will discuss the recently emerging view that regardless of the preterm labor etiology, a common pathway is eventually reached, reflected in cervical changes. The new concept of functional cervical insufficiency is addressed from the perspective of cervical assessment by ultrasound. Although the existing research has not accurately quantified yet the usefulness of ultrasound cervical examination, the technique has become commonplace. Several recent studies have demonstrated a continuum of risk between shorter cervix on ultrasound and higher rate of PTD, leading to the hypothetical argument that women with short cervix on ultrasound might benefit from cervical cerclage. Observational and randomized clinical trials of cerclage as a modality of pregnancy prolongation have provided conflicting results. The relative paucity of data and the conflicting nature of the available evidence dictate caution whenever decisions for cervical monitoring or intervention are made.

Cerclage, Cervical↗
PubMed2006

From concept to practice: the recent history of preterm delivery prevention. Part II: Subclinical infection and hormonal effects.

Under the new cervical insufficiency postulate, the final common pathway theoretically may be influenced by multiple interventions including not only cerclage, but also antibiotics, anti-inflammatory drugs, or progesterone. Since the late 1970s, accumulating evidence has implicated intrauterine infection as a cause of preterm labor. The use of antimicrobial therapy for the prevention of preterm delivery (PTD), although plausible and appealing, has remained largely ineffective so far. A decade of antimicrobial intervention trials to prevent infection-mediated PTD has had disappointing results. Several randomized clinical trials have assessed the role of bacterial vaginosis (BV) treatment in prevention of PTD. The inconsistent results of these trials suggest that other processes, possibly immunomodulation, may be important. Additional factors, still unidentified, pertaining to infectious agent virulence or host immune response modulation, may be responsible for the increased risk of PTD in only a small subset of pregnant women with BV. Even a particular genetic susceptibility was proposed as an intervening factor in the correlation between BV and PTD. Autocrine, paracrine, and endocrine processes in the fetal-placental-uterine unit may contribute to the premature activation of parturitional mechanisms. Progesterone has been used in an attempt to prevent PTD since the 1970s, but the evidence accumulated until the 1990s was fraught by mixed results, and was based mostly on underpowered studies with variable eligibility criteria, including history of spontaneous abortion as an indication for treatment. Two recent randomized, controlled clinical trials restimulated the interest in progesterone supplementation, suggesting that progesterone treatment may influence favorably the rate of preterm delivery, as well as perinatal mortality and morbidity. A major impediment in accepting progesterone as the magic bullet in the prevention of PTD is that its mechanism of action is less well understood than that of all the other prophylactic measures discussed in this review. The optimal formulation, route of administration, dose, and gestational age at initiation have yet to be established. Our ability to quantify prospectively the risk of PTD in a given patient is limited. Moreover, there are limited evidence-based strategies available for prevention of PTD, reflecting our incomplete understanding of the nature of preterm labor. Although an effective instrument in PTD prevention is still elusive, the studies conducted so far have led to a shift in our understanding of cervical insufficiency, infection-mediated PTD, and hormonal influences in human parturition.

Anti-Infective Agents↗
PubMed2006

Chronic renal disease in pregnancy.

The purpose of this review was to examine the impact of varying degrees of renal insufficiency on pregnancy outcome in women with chronic renal disease. Our search of the literature did not reveal any randomized clinical trials or meta-analyses. The available information is derived from opinion, reviews, retrospective series, and limited observational series. It appears that chronic renal disease in pregnancy is uncommon, occurring in 0.03-0.12% of all pregnancies from two U.S. population-based and registry studies. Maternal complications associated with chronic renal disease include preeclampsia, worsening renal function, preterm delivery, anemia, chronic hypertension, and cesarean delivery. The live birth rate in women with chronic renal disease ranges between 64% and 98% depending on the severity of renal insufficiency and presence of hypertension. Significant proteinuria may be an indicator of underlying renal insufficiency. Management of pregnant women with underlying renal disease should ideally entail a multidisciplinary approach at a tertiary center and include a maternal-fetal medicine specialist and a nephrologist. Such women should receive counseling regarding the pregnancy outcomes in association with maternal chronic renal disease and the effect of pregnancy on renal function, especially within the ensuing 5 years postpartum. These women will require frequent visits and monitoring of renal function during pregnancy. Women whose renal disease is further complicated by hypertension should be counseled regarding the increased risk of adverse outcome and need for blood pressure control. Some antihypertensives, especially angiotensin-converting enzyme inhibitors and angiotensin-receptor blockers, should be avoided during pregnancy, if possible, because of the potential for both teratogenic (hypocalvaria) and fetal effects (renal failure, oliguria, and demise).

Chronic Disease↗
PubMed2005

Acute hypertensive emergencies in pregnancy.

OBJECTIVE: Obstetrical hypertensive emergencies are life-threatening conditions involving significant risk to both the mother and fetus. Aggressive treatment of the maternal hypertensive state requires an initial consideration of the effect of treatment on the fetus, via changes to the uteroplacental circulation with treatment. The challenge then is to correct blood pressure using appropriate, safe pharmacologic agents to prevent catastrophic maternal consequences, while minimizing acute changes to placental perfusion and any corresponding fetal ill effects. Hypertension in pregnancy may be one manifestation of a multiple-system pathologic process, as is the case in preeclampsia. Blood pressure control, along with delivery, will be the first step in treating the renal, hematologic, hepatic, and cardiac dysfunction that can be seen in preeclampsia. DESIGN: A review of medications most commonly used for hypertensive emergencies in pregnancy. CONCLUSIONS: Hypertensive emergencies in pregnancy require prompt evaluation and treatment in an intensive care setting to prevent untoward effects to both the fetus and mother.

Acute Disease↗
PubMed2005

Dichorionic twins discordant for thanatophoric dysplasia managed with selective reduction at 20 weeks' gestation: a case report.

BACKGROUND: Thanatophoric dysplasia (TD) is a rare and lethal form of skeletal disorder. A MEDLINE search for 1965-2003 yielded only 3 reports of multiple pregnancies discordant for TD. This is the first case report of selective twin reduction for this diagnosis. CASE: A young woman was seen in consultation at 20 weeks' gestation. Ultrasound examination revealed a twin pregnancy, with ultrasound markers consistent with thanatophoric dysplasia, type II, in twin A. A thick dividing membrane and separated placentas were noted. After counseling, the patient opted for selective termination of twin A. Termination was performed by intracardiac injection of potassium chloride. The pregnancy continued uneventfully until 33 weeks, when spontaneous labor resulted in vaginal delivery of a vigorous female infant, and a mummified, macerated fetus. CONCLUSION: Selective termination for discordant lethal anomalies can be safely performed when the presence of the anomalous twin increases the risk of a poor perinatal outcome for the apparently normal cotwin.

Adult↗
PubMed2004

The effects of dexamethasone and betamethasone on surfactant protein-B messenger RNA expression in human type II pneumocytes and human lung adenocarcinoma cells.

OBJECTIVE: The purpose of this study was to compare the effect of a single 48-hour exposure to betamethasone or dexamethasone in the NCI-H441 cell line and in human type II pneumocytes. STUDY DESIGN: NCI-H441 cells were exposed 48 hours to varying concentrations of betamethasone or dexamethasone (10(-10) to 10(-7) mol/L) alone or in combination with 1 mmol/L dibutyryl cyclic adenosine monophosphate. Likewise, human type II pneumocytes were exposed 48 hours to varying concentrations of betamethasone or dexamethasone (10(-9) to 10(-7) mol/L) alone or in combination with 1 mmol/L dibutyryl cyclic adenosine monophosphate. The measured outcome was the stimulatory effect on surfactant protein B gene transcription as expressed by surfactant protein B messenger RNA accumulation. The experiment was conducted 5 times in NCI-H441 cells and 6 times in type II cells, in parallel with control. Surfactant protein B messenger RNA was determined at control level and 48 hours after exposure by quantitative reverse transcription-polymerase chain reaction. RESULTS: A similar dose-dependent response in surfactant protein B messenger RNA expression was seen with both betamethasone and dexamethasone. In human type II pneumocytes, the inductive profile of surfactant protein B messenger RNA after 48-hour exposure to betamethasone or dexamethasone was similar to that seen in the NCI-H441 cells. CONCLUSION: Dexamethasone and betamethasone achieved similar dose-response patterns of surfactant protein-B expression in vitro.

Adenocarcinoma↗
PubMed2004

Characterization of corticosteroid redosing in an in vitro cell line model.

OBJECTIVE: The purpose of this study was to investigate dexamethasone redosing as function of time and dose. STUDY DESIGN: We studied the effect of 48 hours' exposure to various concentrations of dexamethasone in a human pulmonary adenocarcinoma cell line (H-441). We measured the level of surfactant protein B (SP-B) mRNA by quantitative reverse transcription-PCR after initial dexamethasone exposure, and after redosing, 1 or 2 weeks later. Values are mean +/- SE for 5 experiments. Comparisons were made by Mann-Whitney and Kruskal-Wallis test with significance set at P < .05. RESULTS: Induction of SP-B mRNA was maximal within 48 hours of the initial dexamethasone exposure. Redosing with the same dexamethasone concentration resulted in levels more than double those initially observed. Redosing with dexamethasone concentration 10 times lower had an effect comparable to that of the initial, higher concentration. CONCLUSION: Our results suggest a residual effect of the initial exposure that potentiates redosing, allowing significant dose reductions.

Adenocarcinoma↗
PubMed2003

Gigantomastia complicating mirror syndrome in pregnancy.

BACKGROUND: Gigantomastia is a rare and dangerous condition in pregnancy. Although improvement after delivery is likely, postpartum aggravation is possible. To date, various pharmacological approaches have been tried, with only marginal effectiveness. Surgical intervention is often necessary. CASE: A young woman presented at 32 weeks' gestation with mirror syndrome and gigantomastia. Two years earlier she had had reduction mammoplasty by free nipple transplant. She delivered by cesarean. Rapid postpartum progression of gigantomastia led to breast necrosis and sepsis. The clinical course was complicated by acute respiratory distress syndrome and renal failure. Emergent bilateral simple mastectomy was performed, with subsequent clinical improvement. CONCLUSION: When this devastating condition occurs in pregnancy or postpartum, urgent surgical intervention may prevent potentially fatal complications.

Adult↗
PubMed2003

Antenatal corticosteroids for fetal maturation in women at risk for preterm delivery.

The available data unambiguously support the beneficial, short-term fetal effects of antenatal corticosteroids in women at risk for preterm delivery. There are still several incompletely addressed questions, including the use of corticosteroids in women with preterm premature rupture of membranes, the optimal corticosteroid preparation to be used, and the impact of repeated dosing. These issues are discussed in this review from the perspective of recent scientific evidence on the mechanisms responsible for positive short-term effects on survival and possible harmful long-term effects.

Adrenal Cortex Hormones↗
PubMed2003

In utero cocaine exposure: a thorny mix of science and mythology.

Fetal cocaine exposure has proven to be an area of medicine that has generated more heat than light. Although many reports associate cocaine with a variety of isolated structural anomalies, there is no detectable syndromic clustering, raising doubts about a real causal association or a specific teratogenic action. Potential confounding variables, including the abuse of other drugs, pregnancy deprivations, and socially patterned maternal behaviors, have limited the reliability of observational studies, making it difficult to demonstrate effects solely attributable to cocaine. The clinical expression of in utero cocaine exposure is contextual, critically dependent on the biology/environment interplay. The present work summarizes the fetal structural anomalies that have been associated in the literature with cocaine use during pregnancy, and reviews the putative mechanisms of fetal impairment secondary to cocaine exposure. The final discussion of methodologic issues in cocaine epidemiology highlights the need for innovative approaches to assure that the myths conjured up about "crack babies" are replaced with reliable, high-quality scientific data.

Abnormalities, Drug-Induced↗
PubMed2003

Gestational diabetes: a field of controversy.

UNLABELLED: Many clinicians in the United States routinely screen all pregnant women in their practices for gestational diabetes. Recently, the US Preventive Services Task Force re-emphasized that such screening is not supported by rigorous scientific evidence. Recommendations for diagnosis and management are based on an even scantier scientific foundation. Although this review questions several aspects of current dogma, it, too, is based on the frequently flawed existing data. It is surprising how, in spite of an abundance of published information on the subject, we continue to be ignorant of the real benefits of the widespread practice of screening and treating for gestational diabetes. The authors hope that the results of a randomized clinical trial, now in progress, will help to resolve some of the controversies surrounding gestational diabetes. TARGET AUDIENCE: Obstetricians & Gynecologists, Family Physicians. LEARNING OBJECTIVES: After completion of this article, the reader should be able to describe the controversy surrounding the significance of gestational diabetes, to break down the data regarding the efficacy of screening for gestational diabetes, and to outline potential treatment options for gestational diabetes.

Diabetes, Gestational↗
PubMed2003

The unrealized potential of prenatal care. A population health approach.

To review the scientific evidence behind the traditional view that prenatal care improves pregnancy outcomes. The literature published in English between 1965 and 2002 was searched for relevant studies and opinions on prenatal care outcomes. As search engine we used the MEDLINE bibliographic database, employing a combination of keywords, including pregnancy, prenatal care and outcomes. Editorials, proceedings of meetings and reviews, were included in the analysis. This review was not intended to be a systematic or exhaustive review of the literature on prenatal care. The significant heterogeneity of the retrieved papers made any aggregation impossible. In each of the reviewed studies we assessed the methodologic aspects and validity of conclusions, using established criteria for the evaluation of prenatal interventions. Our processing of editorials and other personal opinions was conducted with the intention to draw the line between statements based on scientific evidence and speculative, emotional or traditional concepts. Outcomes research related to prenatal care is marred by methodologic flaws and conceptual problems. While traditional prenatal protocols are based on an individual-centered medical care system, the outcomes are measured using population-based parameters. Interventions capable of improving maternal and neonatal outcomes at the population level are more likely to be social and economic rather than health interventions case by case.

Community Health Planning↗
PubMed2002

Mirror syndrome. A case report.

BACKGROUND: Water retention in a pregnant woman can mirror fetal hydropic changes. This clinical presentation has been named "mirror syndrome." Awareness of the syndrome is important due to the associated fetal and maternal risks. CASE: A 26-year-old woman, gravida 3, para 1011, presented at 31 weeks' gestation with significant edema and a 7-km weight gain in one week. Sonographic evaluation revealed hydramnios and fetal ascites. Maternal workup was negative for preeclampsia, diabetes, or cardiac or renal dysfunction. A workup for nonimmune hydrops was also negative. Over the next three days there was progression of maternal edema. With diagnosis of mirror syndrome, the decision for delivery was made. Both neonate and mother subsequently did well, with normalization of ascites and edema, respectively. CONCLUSION: Our case, along with 19 reviewed in the literature, reiterate the features of mirror syndrome and provide an opportunity to dispel some of the misconceptions in the literature. The condition is frequently mistaken for preeclampsia, although distinguishing characteristics can be identified. Mirror syndrome is a manifestation of extremely severe fetal hydrops. When the specific cause of fetal hydrops cannot be identified and corrected, immediate delivery is necessary in order to avoid fetal death and maternal complications.

Adult↗