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Biomedical subjects

D M Main

Publications and source records attributed to D M Main.

At least 19 recordsLinked to original sources

Clinical differentiation of oral ulceration in Behçet's disease.

Behçet oral ulceration (BOU) is described as being indistinguishable from conventional recurrent oral ulceration (ROU). A clinical comparison between 38 Behçet patients and 38 control ROU cases was effected by completion of a standard questionnaire. Behçet patients reported an increased number of concurrent ulcers and involvement of the soft palate and oropharynx. No differences were detected with respect to duration, frequency, age of onset or family history. In addition, photographs of BOU in 15 patients revealed the concurrence of atypical aphthous and herpetiform varieties. Number, site and appearance of oral ulceration may therefore provide diagnostic features for the development of Behçet's disease.

Behcet Syndrome

Determination of volumes of fluid in the mouth by fluoride dilution.

A dilution technique, with fluoride as a marker, has been developed to measure the volume of saliva and other fluids in the mouth. Immediately after swallowing, a small amount of fluoride solution is placed in the mouth, mixed with the oral fluids, and expelled from the mouth. The fluoride concentration of the expelled oral fluid is measured and the volume of fluid in the mouth at the time of spitting calculated from the fluoride dilution. Mean values of 0.75 +/- (SD) 0.28 ml for males and 0.72 +/- (SD) 0.16 ml for females were recorded. The accuracy of the volume determination is about +/- 0.10 ml in vivo. This technique has provided a convenient and rapid means of determining saliva volumes. It could also be used to determine rates of secretion and may prove useful in the clinic for assessing a patient's salivary competence.

Adult

Extended longitudinal study of uterine activity among low-risk women.

Eighty-nine black women without major medical risks for preterm labor participated in this longitudinal, prospective study for the evaluation of usual prelabor uterine activity and for the assessment of how gestational age, time of day, maternal weight, age, and parity affected contraction frequency. Participants wore an ambulatory tocodynamometer for 72 consecutive hours at three points in gestation during the second and early third trimesters while engaged in usual home and work activity. Data obtained from the 81 women with uncomplicated term pregnancies demonstrated a significant increase in contraction frequency with advancing gestational age between 22 and 33 weeks. After 26 weeks, significantly more uterine activity occurred at night. Perhaps because of detection difficulties, contraction frequency was inversely related to maternal weight in women weighing greater than 112% ideal weight. Maternal age and parity did not affect contraction frequency. Contraction characteristics of eight women experiencing preterm labor or medically indicated preterm delivery are described.

Adolescent

Differences in in vitro growth of epithelium from inflammatory and developmental odontogenic cysts.

Ninety-three odontogenic cysts, 42 of inflammatory and 51 of developmental origin, were grown in vitro from explants and/or cell suspensions. There was little difference in the success rate of culturing epithelium from explants of dentigerous cysts (N = 28) or odontogenic keratocysts (N = 23) (approximately 75% and 87%, respectively) and the dentigerous cyst grew particularly well from suspensions (N = 11) (91%) compared with the keratocyst (N = 19) (58%). Epithelium from developmental odontogenic cysts grew much better in vitro than did cysts of inflammatory origin (56 to 58% from explants and 19 to 25% from suspension). From this work there is little evidence to support previous statements that the dentigerous cyst cannot be grown from explants, or that the odontogenic keratocyst has 'aggressive' growth characteristics.

Cells, Cultured

Risk factors for preterm premature rupture of the fetal membranes.

Preterm premature rupture of the membranes (PPROM) is a significant cause of prematurity, accounting for approximately one third of preterm births in the United States. PPROM occurs in approximately 0.7-2% of all pregnancies nationally, and has a reported recurrence rate of 21%. The elucidation of potential risk factors for PPROM could contribute to a better understanding of its etiology. To study the contributions of 20 potential risk factors, we undertook a case-control study in our clinic population, which has a 5-6% incidence of PPROM. One hundred and thirty-three patients experiencing PPROM were matched for race, age, parity and gestational age with undelivered patients. Studies performed included ultrasonographic examinations, blood levels of ascorbic acid and zinc, microbiologic assays, patient questionnaires, and chart reviews. After stratification of both groups into subgroups based on matching criteria, summary tests of significance and Mantel-Haenszel tests of odds ratios were performed. On univariate analysis the following factors achieved significance at the p less than 0.05 level with 95% confidence intervals: 1) previous history of PPROM 2) smoking (dose related) 3) fundal location of the placenta in the present pregnancy. 4) a prior history of cerclage. After regression analysis, we concluded that smoking and history of previous PPROM were found to be risk factors for PPROM in our inner city black population.

Analysis of Variance

Acute herpetic stomatitis: referrals to Leeds Dental Hospital 1978-1987.

The clinical data of 102 patients referred to Leeds Dental Hospital from 1978 to 1987 with acute herpetic stomatitis confirmed by laboratory investigations were analysed. No gender difference was found. Differences in age distribution were marked. Only 5% of patients were aged less than 11 years, whereas the majority of cases (51%) occurred during the third decade. Statistical analysis confirmed a general trend for the mean age of patients to have increased progressively over the 10-year period.

Acute Disease

Follicular cysts of mandibular third molar teeth: radiological evaluation of enlargement.

To test the hypothesis that follicular (dentigerous) cyst enlargement arises from impeded tooth eruption, data from standardized Orthopantomographs of 30 uninfected, wholly intracortical cysts associated with mandibular third molar teeth were analysed. Cyst areas were measured with a computer-aided image analyser (Magiscan 2, Joyce Loebl, Gateshead, UK). Two size categories, small and large, each comprising 15 cases, were distinguished. These were correlated with the radiographic variables of cyst relationships to tooth crown, and angulation and nature of impaction of associated tooth. Cyst enlargement is most active in the third and fourth decades of life. Smaller cysts were associated with teeth impacted against adjacent tooth or bone, whereas larger cysts developed predominantly from horizontally angulated teeth intruded endosteally. These findings lend support to the haemodynamic concept of follicular cyst enlargement linked with dysfunctional eruptive forces.

Adult

Controlled trial of a Preterm Labor Detection program: efficacy and costs.

Patient education regarding the signs and symptoms of preterm labor combined with frequent clinical evaluations has been advocated as a means to reduce preterm births. Over a 3.5-year period, the risk for preterm labor was determined in 943 indigent black inner-city women using the Papiernik-Creasy scoring system. High-risk women were allocated randomly to a Preterm Labor Detection Clinic or to serve as high-risk controls. Women with lower risk scores served as low-risk controls. Women from both control groups were not informed of their risk status, and both groups received prenatal care in standard obstetric clinics. Women accepting the Preterm Labor Detection Clinic Program received comprehensive patient education and were seen weekly starting at 22 weeks' gestation. Despite this extensive outpatient program, there were no significant differences between the high-risk groups with respect to mean gestational age at delivery, mean birth weight, or percentage delivering before term as a result of preterm labor or premature rupture of membranes (PROM). Evaluations of inpatient charges revealed no significant differences due to participation in this program, although outpatient clinic utilization and charges were increased significantly for Preterm Labor Detection Clinic patients. Failure of this program to reduce preterm birth may relate to the relatively low overall rate of women presenting in preterm labor with advanced cervical dilation. In contrast, high rates of PROM and fetal death occurred in all three study groups.

Clinical Trials as Topic

The role of ultrasound in the management of preterm labor.

Careful ultrasonographic evaluations of patients with PTL or PROM can provide critical information about estimated gestational age and birthweight. In addition, examination of FBM and perhaps objective ultrasonographic measurements of the lower uterine segment and cervix may provide valuable information to help us distinguish true preterm labor from false labor. Further research in these areas is necessary before these new approaches are widely adopted.

Anthropometry

The epidemiology of preterm birth.

The immediate causes of preterm birth (preterm labor, PPROM, maternal complications, and fetal distress) are well-established. Similarly, the epidemiologic and medical risk factors discussed are well-known. Most risk factors, unfortunately, are not easy to modify. Furthermore, the connection between epidemiologic risks and preterm birth is often unclear. As this brief discussion of potential mediators linking risk status to preterm birth indicates, much more research is needed to define and assess potential mechanisms. It is unclear how important the five mediating factors chosen for presentation will prove to be or if other more significant mechanisms exist. However, as Eastman noted 40 years ago, "only when the factors causing prematurity are clearly understood, can any intelligent attempt at prevention be made."

Female

Intermittent weekly contraction monitoring to predict preterm labor in low-risk women: a blinded study.

To assess the predictive value of uterine activity as a marker for subsequent preterm labor, 139 black, inner city women were monitored at least three times for 1 hour between 28-32 weeks' gestation using a portable tocodynamometer. All had singleton gestations and gave no previous history of preterm labor or delivery. They were monitored between 8 and 10 AM while sitting in the clinic waiting area. Uterine activity records, numbered randomly, were transmitted by telephone to a site remote from the hospital. No one having any clinical contact with the participants saw or received feedback regarding the contraction data. Tocodynamometry records were then mailed to another center where they were read by one investigator blinded to all clinical information. The mean contraction frequency during the single hour of weekly testing was significantly greater for the 16 women who developed preterm labor than for women who delivered at term at each point between weeks 28-32. Using greater than six contractions per hour on at least one occasion between 28-32 weeks' gestation as a predictor would have identified 12 of 16 women (sensitivity 75%) who subsequently developed preterm labor. This contraction frequency was noted in 26 of 123 women (21%) who labored at term (specificity 79%; P = .0003).

Female

Chronic oral terbutaline tocolytic therapy is associated with maternal glucose intolerance.

Plasma glucose determinations were performed 1 hour after a 50 gm oral glucose load in 30 patients receiving long-term terbutaline therapy (20 to 40 mg/day for at least 1 week) and 247 normal control patients. A total of 63% of patients receiving terbutaline had an abnormal 1-hour value (greater than or equal to 140 mg/dl), an incidence much higher than that of control subjects (17.8%) (p less than 0.0001) for a relative risk of 3.54 (95% confidence intervals of 2.29 to 5.42). Mean 1-hour values were 112.1 mg/dl for control subjects and 149.8 mg/dl in the terbutaline group (p less than 0.0001). All abnormal values were followed by a 3-hour 100 gm oral glucose tolerance test. A total of 15.9% of the glucose tolerance tests performed in the control group (2.8% overall) were abnormal as opposed to 52.6% (33.1% overall) in patients receiving terbutaline (p less than 0.01). Nine patients were studied before and after terbutaline therapy. Results obtained during administration of terbutaline were significantly higher (102.2 mg/dl before therapy versus 145.2 mg/dl during therapy). We conclude that treatment with oral terbutaline appears to be associated with impairment of glucose tolerance in pregnancy.

Administration, Oral

Risk scoring for preterm labor: where do we go from here?

Risk scoring systems based on traditional demographic, social, and medical factors have limited use, especially in certain populations. Newer approaches, including frequent cervical examinations, periodic outpatient monitoring for contractions, extensive daily monitoring at home for contractions in very high-risk persons, and identification and reduction of modifiable behavioral risks, offer promise.

Behavior

Prospective evaluation of a risk scoring system for predicting preterm delivery in black inner city women.

Nine percent of United States births are preterm. The ability to efficiently identify women destined to deliver before term would enable obstetricians to initiate early intervention. The Papiernik-Creasy risk scoring system is being extensively applied for this purpose, without prospective validation in this country. We evaluated prospectively its ability to predict high risk women in a black inner city population, when applied once early in pregnancy. The system, based on social, past medical, and current pregnancy problems, failed to identify at-risk patients. Adjusting the score cutoff and reweighting factors with discriminate analysis did not improve the predictive value. Analysis of an additional 60 social, demographic, and medical factors failed to produce a useful alternative risk assessment tool. We suggest that risk scoring systems such as these may not be helpful in socioeconomically at-risk populations.

Adult