Biomedical subjects

Mark C Chames

Publications and source records attributed to Mark C Chames.

4 recordsLinked to original sources

PubMed2006

Risk factors for the breakdown of perineal laceration repair after vaginal delivery.

OBJECTIVE: The purpose of this study was to identify risk factors that are associated with the breakdown of perineal laceration repair in the postpartum period. STUDY DESIGN: We conducted a retrospective, case-control study to review perineal laceration repair breakdown in patients who were delivered between September 1995 and February 2005 at the University of Michigan. Bivariate analysis with chi-square test and t-test and stepwise logistic regression analysis were performed. RESULTS: Fifty-nine cases and 118 control deliveries were identified from a total of 14,124 vaginal deliveries. Risk factors were longer second stage of labor (142 vs 87 minutes; P = .001), operative vaginal delivery (odds ratio, 3.6; 95% CI, 1.8-7.3), mediolateral episiotomy (odds ratio, 6.9; 95% CI, 2.6-18.7), third- or fourth-degree laceration (odds ratio, 3.1; 95% CI, 1.5-6.4), and meconium-stained amniotic fluid (odds ratio, 3.0; 95% CI, 1.1-7.9). Previous vaginal delivery was protective (odds ratio, 0.38; 95% CI, 0.18-0.84). Logistic regression showed the most significant factor to be an interaction between operative vaginal delivery and mediolateral episiotomy (odd ratio, 6.36; 95% CI, 2.18-18.57). CONCLUSION: The most significant events were mediolateral episiotomy, especially in conjunction with operative vaginal delivery, third- and fourth-degree lacerations, and meconium.

Adult↗

PubMed2004

Uncoupling-mediated generation of reactive oxygen by halogenated aromatic hydrocarbons in mouse liver microsomes.

Studying liver microsomes from 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-induced or vehicle-treated (noninduced) mice, we evaluated the in vitro effects of added chemicals on the production of reactive oxygen due to substrate/P450-mediated uncoupling. The catalase-inhibited NADPH-dependent H(2)O(2) production (luminol assay) was lower in induced than noninduced microsomes. The effects of adding chemicals (2.5 microM) in vitro could be divided into three categories: Group 1, highly halogenated and coplanar compounds that increased H(2)O(2) production at least 5-fold in induced, but not in noninduced, microsomes; Group 2, non-coplanar halogenated biphenyls that did not affect H(2)O(2) production; Group 3, minimally halogenated biphenyls and benzo[a]pyrene that decreased H(2)O(2) production. Molar consumption of NADPH and O(2) and molar H(2)O(2) production (o-dianisidine oxidation) revealed that Group 1 compounds mostly increased, Group 2 had no effect, and Group 3 decreased the H(2)O(2)/O(2) and H(2)O(2)/NADPH ratios. Microsomal lipid peroxidation (thiobarbituric acid-reactive substances) was proportional to H(2)O(2) production. Although TCDD induction decreased microsomal production of H(2)O(2), addition of Group 1 compounds to TCDD-induced microsomes in vitro stimulated the second-electron reduction of cytochrome P450 and subsequent release of H(2)O(2) production. This pathway is likely to contribute to the oxidative stress response and associated toxicity produced by many of these environmental chemicals.

Animals↗

PubMed2003

Subsequent pregnancy outcome in women with a history of HELLP syndrome at < or = 28 weeks of gestation.

OBJECTIVE: The purpose of this study was to describe subsequent pregnancy outcome in women with a history of hemolysis, elevated liver enzymes, and low platelet count syndrome for which delivery occurred at < or = 28 weeks of gestation during the index pregnancy. STUDY DESIGN: A descriptive report of women with previous hemolysis, elevated liver enzymes, and low platelet count syndrome who were delivered between August 1984 and July 1998 at the E.H. Crump Women's Hospital (Memphis, Tenn) and between March 1994 and July 1998 at the Central Baptist Hospital (Lexington, Ky). To have adequate time to study subsequent pregnancy outcome, only patients who were delivered >2 years before the analysis were included. Medical records of the index pregnancy and subsequent outcomes were available for review. RESULTS: Adequate follow-up data were available in 69 patients; the median duration of follow-up was 5 years (range: 2-14 years). There were 76 subsequent pregnancies among 48 women, of which 62 pregnancies (82%) progressed beyond 20 weeks of gestation. Preeclampsia developed in 34 of 62 subsequent pregnancies (55%). Recurrent hemolysis, elevated liver enzymes, and low platelet count syndrome developed in 4 of these pregnancies (6%), and abruptio placentae developed in 3 of these pregnancies (5%). There were no cases of eclampsia in our population. Delivery before 37 weeks of gestation occurred in 33 of the cases (53%), and 17 of the newborn infants (27%) were small for gestational age (<10th percentile). The perinatal mortality rate was 11%. CONCLUSION: Patients with a history of hemolysis, elevated liver enzymes, and low platelet count syndrome at < or = 28 weeks of gestation during the index pregnancy are at increased risk for obstetric complications in subsequent pregnancies. Overall, however, the rate of recurrent hemolysis, elevated liver enzymes, and low platelet count syndrome is only 6%.

Adult↗

PubMed2002

Late postpartum eclampsia: a preventable disease?

OBJECTIVE: The purpose of this study was to determine whether there is a shift in the timing of eclampsia in relation to delivery and whether traditional symptoms precede impending postpartum eclampsia. STUDY DESIGN: A multicenter analysis of data from patients with eclampsia from March 1996 through February 2001 at the University of Cincinnati, the University of Tennessee, Memphis, and Central Baptist Hospital, Lexington. Data were collected regarding the relationship of the patient's first seizure to delivery, prodromal symptoms, neuroimaging studies, use of magnesium sulfate, antihypertensive therapy, and follow-up medical care. The analysis focused on women who had late postpartum eclampsia. RESULTS: During the study period, 89 patients were diagnosed with eclampsia. Twenty-nine women (33%) had postpartum eclampsia, of whom 23 women (79%) had late onset (>48 hours). Interestingly, only 5 of these 23 women (22%) had been previously diagnosed with preeclampsia. Twenty-one patients (91%) with late postpartum eclampsia had at least 1 prodromal symptom, and 12 patients (52%) had >1 symptom that heralded the seizure: 20 women (87%) had headache; 10 women (44%) had visual changes; 5 women (22%) had nausea or vomiting; and 2 women (9%) experienced epigastric pain. Only 7 of these 21 women (33%) sought care for their symptoms, of whom 6 women (86%) had clinical evidence of preeclampsia that was not considered by the treating physician. Among all patients with eclampsia, there were 7 cases of aspiration pneumonia, 3 cases of pulmonary edema, 3 cases of pleural effusion, 2 cases of disseminated intravascular coagulation, and no cases of maternal death. CONCLUSION: Current obstetric treatment in the United States has resulted in a shift of eclampsia toward the postpartum period, with most cases being seen as late post partum. To reduce the rate of late postpartum eclampsia, efforts should be directed to the education of the health care providers and patients regarding the importance of prompt reporting and evaluation of symptoms of preeclampsia during the postpartum period.

Eclampsia↗