Biomedical subjects
Publications and source records attributed to W E Roberts.
A systematic approach to the prenatal and postnatal evaluation of the patient at risk for fetal skeletal anomalies is outlined. The more common anomalies are described within a differential diagnosis table, and a case study is presented.
Ultrasound has become integrally involved in the medical management of obstetric patients. The decision to incorporate sonography into a routine obstetric and gynecologic practice requires input from all members of the practice. Only when there is such a commitment will patient care be optimal. Regardless of whether one believes that routine screening will improve perinatal outcome, the consensus is that timely and appropriate obstetric ultrasound examinations are beneficial.
Home monitoring accurately detects contractions, and thus is useful in predicting preterm labor. Appropriate physician action is necessary to significantly prolong pregnancy even in the presence of evidence of excessive contractions. Despite conflicting studies, the majority of evidence heavily favors the use of monitoring as part of a comprehensive preterm birth prevention program. Indeed, monitoring has greater clinical utility in twin gestations because of the recognized propensity for preterm labor. Fetal fibronectin is one of the most sensitive and specific markers for preterm labor and subsequent early delivery presently available. It appears to be equally effective in multifetal gestations compared with singleton gestations, but intervention trials are needed to substantiate its clinical effectiveness. Cervical status monitoring by ultrasound correlates inversely with preterm labor, but studies in twin gestation are currently lacking. Other markers, such as salivary estriol for preterm labor, have yet to be assessed as predictors of preterm labor among multifetal gestations.
BACKGROUND: The incidence of second twin delivery by cesarean section and whether obstetric parameters are predictive should be studied. METHODS: In this retrospective study, all vertex-vertex twin deliveries during a 48-month period were reviewed. RESULTS: During the study period, 106 sets of vertex-vertex twins were identified. In 68 pairs, both were delivered vaginally (group 1), and 21 pairs were born via cesarean section. In the 17 pairs in group 2, the first infant was delivered vaginally and the second by cesarean section because of fetal distress in 6 cases (35%), cord prolapse in 6 (35%), abnormal/unstable lie in 4 (23%), and abruptio placenta in 1 case (6%). The only maternal factor associated with abdominal delivery for twin B was greater maternal age. When cesarean delivery was required for twin B, a longer interval between deliveries and a lower Apgar score were noted. CONCLUSION: Cesarean birth of twin B is a more common clinical event than previously reported but is not easily predicted by obstetric parameters.
BACKGROUND: Pregnancy-related adult respiratory distress syndrome (ARDS) can lead to maternal mortality and morbidity. METHODS: Records of all pregnant patients diagnosed with ARDS over a 14-year period were reviewed and the cases were stratified into survivors and nonsurvivors. RESULTS: Forty-one cases were identified and 31 survived (maternal mortality rate of 24.4%). Adult respiratory distress syndrome was diagnosed in the antepartum period in 23 (56.1%) of the patients and the majority of these cases occurred in the third trimester (73.9%). There was no statistically significant difference in demographic characteristics, preexisting diseases, or probable precipitating cause for the development of ARDS between the two groups. The cause of death among the nonsurvivors included multisystem organ failure, sepsis, cardiac arrest, and disseminated intravascular coagulopathy. CONCLUSION: Pregnancy-related ARDS continues to be associated with a high maternal mortality rate (25%). Unfortunately, the etiology for ARDS during pregnancy is not predictive of maternal outcome.
PURPOSE: Following parenteral magnesium tocolysis for patients in preterm labor. The choice of oral tocolytic medications is controversial. METHODS: Over a six-month period, 47 patients who were inpreterm labor were randomized after parenteral magnesium tocolysis to receive magnesium gluconate ([Mg-g] 648 mg elemental magnesium/day) or magnesium chloride ([Mg-c] 640 mg elemental magnesium/ day). A serum magnesium was obtained 24 hours after the initiation of oral therapy. RESULTS: In the 25 patients were treated with Mg-g and 22 with Mg-c there were no differences in patient demographics, initial cervical dilatation hours on parenteral magnesium sulfate, recurrent contractions, or side effects between the two groups. The cost was also similar (Mg-c, $1.40/d; Mg-g, $2.11/d). The serum magnesium levels were higher in the Mg-c group (1.80 +/- 0.28 mg/dl) compared to the Mg-g group (1.63 +/- 0.30 mg/dl) but the difference was not significant. CONCLUSION: These two preparations of magnesium are similar in their effects on uterine activity and serum levels when used at these dosages.
OBJECTIVE: Our purpose was to determine whether intrapartum obstetric interventions are associated with umbilical cord prolapse. STUDY DESIGN: A computer search identified patients who had intrapartum umbilical cord prolapse. Thirty-seven cases were identified between 1990 and 1994 (incidence of 1.85 per 1000). These women were randomly matched to control patients with intact membranes. RESULTS: Patients with umbilical cord prolapse were delivered earlier (34.8 vs 37.1 weeks, p = 0.05). Otherwise, there were no differences between groups regarding the use of cervical ripening, incidence of labor induction, or the use of amnioinfusion and amniotomy. Although cervical dilatation and station were similar between groups at the time of admission, women with umbilical cord prolapse did not have as much descent of the presenting part associated with cervical dilatation and progressive labor compared with control patients. CONCLUSION: By themselves, obstetric interventions of cervical ripening, labor induction, amnioinfusion, and amniotomy do not increase the likelihood that a patient will have umbilical cord prolapse.
OBJECTIVE: Our purpose was to review recent obstetric literature detailing the subsequent delivery experience of patients with a prior low-segment vertical cesarean incision and to derive recommendations for practice on the basis of this information. STUDY DESIGN: Ten studies that included information about pregnancy outcome in patients with prior low-segment vertical cesarean operations were retrieved and reviewed from the American obstetric literature since 1981 and from a review of all abstracts presented annually since 1981 to the Society of Perinatal Obstetricians. RESULTS: Altogether, information about subsequent pregnancy outcome for 382 patients with prior low-segment vertical cesarean delivery was available for analysis. Among the 372 patients with complete patient population information, vaginal delivery was safely accomplished in 306 (82%). Four uterine ruptures (1.05%) have been reported, only one of which occurred after a single prior unextended low-segment vertical cesarean incision. Two ruptures occurred elsewhere on the lateral or posterior aspect of the uterus in subsequent pregnancies, and the fourth rupture occurred at the juncture of prior low vertical and transverse incisions. No perinatal mortality or permanent perinatal morbidity was encountered with these pregnancies. CONCLUSIONS: In the otherwise uncomplicated pregnancy the patient with one previous nonextended low-segment vertical cesarean incision should be considered to have a prior low-segment scar and as such be a candidate for trial of labor in her current singleton pregnancy. The same care, counseling, and caution should be exercised for this patient as for one with a prior low-segment transverse incision.
STATEMENT OF PROBLEM: The use of implants for orthodontic anchorage can produce superior preprosthetic tooth positions. Their use often requires a crown or prosthesis to be fabricated for use as a connection between the orthodontic devices and the implant. PURPOSE: In this article, factors that affect the design of prostheses required for orthodontic movement and examples of prosthesis designs and materials, based on the authors' experience, are presented.
OBJECTIVE: To determine whether two techniques of vacuum extraction delivery-continuous vacuum and intermittent vacuum-have different effects on maternal-fetal outcomes. METHODS: Patients to be delivered by vacuum extraction were randomized to receive continuous or intermittent vacuum. All deliveries were performed using the M-cup. In the continuous group, the level of vacuum was brought to 600 mmHg between contractions and was maintained at that level until delivery of the infant. Active efforts were made to prevent fetal loss-of-station between contractions by maintaining traction. In the intermittent group, the level of vacuum was decreased to 100 mmHg between contractions and no effort was made to prevent fetal loss-of-station. RESULTS: A total of 322 patients were randomized: 164 in the continuous arm and 158 in the intermittent group. The continuous method did not effect delivery faster (continuous 167 +/- 175 seconds versus intermittent 167 +/- 150 seconds; P = .97), nor did it lead to a reduction in method failures (continuous 12, intermittent nine; P = .72). The intermittent method did not appear to offer any benefit to the neonate regarding cephalhematoma formation (continuous 20, intermittent 17; P = .686) or any other measure of neonatal outcome. Maternal lacerations and episiotomy extensions were evenly distributed between the groups. Overall, the efficacy rate of the vacuum cup was 93.5% and the cephalhematoma rate was 11.5%. CONCLUSION: No differences in maternal or fetal outcome could be demonstrated if the level of vacuum was decreased between contractions or if an effort was made to prevent fetal loss-of-station. The clinical results obtained in this trial using the M-cup are similar to the published results with the stainless-steel Malmstrom cup.
Independent external monitoring committees are an important part of scientific clinical trials. They monitor patient safety, study progress, investigators' performance, and accurate interpretation/reporting of the study data. Data trends observed by a study monitoring committee detected a change in the pattern of patient screening by investigators after an increased awareness that tobacco use could directly compromise the osseointegration of root-form dental implants. This increased awareness is believed to have altered the number of active smokers accepted into a multicenter prospective dental implant study. Recent data analyses indicate that the success ratios were improved by alterations in this discretionary inclusion-exclusion criterion.
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The purpose of this study was to examine the angiogenic and the subsequent osteogenic responses during a 96-hour time-course after sutural expansion. Fifty rats were divided into: (1) a control group that received only angiogenic induction through injection of 5 ng/gm recombinant human endothelial cell growth factor (rhECGF); (2) an experimental group that received orthopedic expansion and rhECGF; (3) a sham group that received expansion and sodium chloride (NaCl) injection; and (4) a baseline group that received no expansion or injection. All rats were injected with 3H-thymidine (1.0 microCi/gm) 1 hour before death to label the DNA of S-phase cells. Demineralized sections (4 microm thick) were stained with hematoxylin and eosin. Angiogenesis and cell migration were analyzed with a previously established cell kinetics model. Analysis of variance was used to test the hypothesis that enhancement of angiogenesis stimulates reestablishment of osteogenic capability. Blood vessel number, area, and endothelial cell-labeled index significantly increased in experimental groups, but no difference was found between control and baseline groups. Labeled-pericyte index and activated pericyte numbers in the experimental group were also higher than in the sham groups. These results show that supplemental rhECGF enhances angiogenesis in expanded sutures but not in nonexpanded sutures. Data also suggest that pericytes are the source of osteoblasts in an orthopedically expanded suture.
Rigidly integrated implants offer great promise for orthodontic and orthopedic anchorage in the oral and midfacial regions. Rigid anchorage can be used to control unwanted tooth movement, provide abutments in edentulous arches, and open the vertical dimension of occlusion. To evaluate the use of endosseous implants in the midface region, two flanged titanium implants were placed on either side of the midnasal suture of 18 New Zealand White rabbits. The rabbits were divided into an unloaded control and two experimental groups. One experimental group was loaded at 1 Newton (N) and the other at 3 N. All rabbits were euthanized after 12 weeks of loading. Stereologic point-hit and line-intercept methods were used to analyze microradiographic and multiple fluorochrome histology of the suture. All implants remained stable during the loading period. The distance between the implants increased significantly in the loaded groups compared with the control, and was significantly higher in the 3 N group than in the 1 N group. Percent bone volume was significantly decreased, while the percent suture volume tended to be increased in the loaded groups. Mineral apposition and bone formation rates at the sutural surfaces were increased in the loaded groups (P < 0.05), but did not differ between loaded groups. These results indicate that relatively low loads (1 or 3 N) applied to rigidly integrated endosseous implants across an unfused suture are satisfactory for achieving expansion under the conditions of this study. The 3 N load resulted in slightly more expansion, but did not affect the rate of bone formation at the suture.
OBJECTIVE: To assess the effect of home uterine contraction assessment (HUCA) in twin pregnancies with preterm labor (PTL) at < 24 weeks' gestation. STUDY DESIGN: In this retrospective, analytic study, patients were stratified by whether HUCA had been prescribed before or after diagnosis of PTL. The main outcomes studied were time of PTL diagnosis and delivery as well as birth weight and need for neonatal intensive care unit (NICU) admission. In 63 patients, 32 were prescribed HUCA after PTL had been arrested at < 24 weeks (group I). Thirty-one women had HUCA prescribed at 20 weeks' gestational age and then developed PTL at < 24 weeks (group II). RESULTS: Labor was diagnosed at similar times in both groups (22.8 vs 23.4 weeks), but delivery was earlier in group I (27.6 weeks vs. 34.7 weeks) than in group II. The birth weight in group I was less (918 +/- 255 g), and of the 64 infants, 55 required NICU admission as compared to 2,340 +/- 525 g and 11 of 62 infants (P < .0001, .0001) in group II, respectively. CONCLUSION: Women with twin gestations and the diagnosis of PTL prior to 24 weeks deliver later in gestation, and their infants weigh more and have fewer NICU admissions if intensive prenatal surveillance is prescribed prior to the onset of labor.
OBJECTIVE: To identify factors involved in the development of fetal cephalohematoma from vacuum extraction. STUDY DESIGN: Patients at > or = 34 weeks' gestation were randomly assigned to delivery by vacuum (n = 322) using the continuous (n = 164) or intermittent (n = 158) technique. Neonatal outcome with cephalohematoma was analyzed subsequently and related to prospectively recorded data. RESULTS: Approximately equal numbers of cephalohematoma were recorded in the two groups (continuous 20, intermittent 17; P = .686). Station at point of application (P = .008), increasing asynclitism (P < .001) and increasing application to delivery time (P = .002) correlated significantly with cephalohematoma. Only the last two factors achieved significance after stepwise multiple logistic regression analysis. Factors that did not achieve statistical significance were gestational age (P = .755), birth weight (P = .982), instrumental rotation (P = .896) and previous vaginal delivery (P = .051). CONCLUSION: In this prospective, randomized, controlled trial of vacuum-assisted delivery, the only predelivery factor found to predispose to neonatal cephalohematoma formation was increasing asynclitism. Although cephalohematoma formation was more likely to develop as the duration of vacuum application increased during delivery, only 28% of neonates exhibited this finding when the time from vacuum application to delivery exceeded five minutes.
Since 1990, clinical achievement in orthodontics has been a graduation requirement at Indiana University. To be certified for graduation, all dental students must treat at least one limited orthodontic problem and observe the retention of at least one previously treated, limited orthodontics patient. Although clinical orthodontics for adults appears to be a very successful addition to the predoctoral curriculum, the specific accreditation requirements that mandated it have been rescinded. However, the positive response of the students, apparent acceptance by the orthodontic community, and the national acclaim afforded the program indicate that a hands-on clinical experience in orthodontics is a positive addition to the predoctoral curriculum.
Osteoporosis (OP) is a systemic condition that has dental implications. The purpose of this study was to compare OP risk among various dental specialty subpopulations at Indiana University School of Dentistry (IUSD). A survey was administered to 220 adult female dental patients assessing menstrual status and risk behaviors associated with low bone mass. The subjects' mean age was 48.2 +/- 1.1 years (mean +/- SEM). Overall, 38% of the surveyed patients exhibited high risk for OP. The orthodontic subpopulation (a dentate group with routine developmental malocclusions) was the youngest group and contained the lowest percentage at high-risk (6%). Conversely, the complete denture subpopulation was the oldest and contained the highest percentage of patients at high risk (53%). Postmenopausal women who had inadequate hormone replacement therapy exhibited a strong negative correlation for number of teeth retained with increasing years postmenopause (r = 0.6). Patients in the implant therapy group (many of which had adjunctive orthodontic care) had a mean age similar to the complete denture group, but a much lower risk for OP. This appears to be due to the extensive counseling these patients receive prior to treatment. It is concluded that risk factor analysis and patient counseling may be effective measures for reducing the osteoporosis risk of dental patients.