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Biomedical subjects

D M Main

Publications and source records attributed to D M Main.

At least 37 records · Page 2Linked to original sources
PubMed1988

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↗
PubMed1987

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↗
PubMed1987

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↗
PubMed1987

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↗
PubMed1986

Maternal acetaminophen overdose at 15 weeks of gestation.

Acetaminophen is a common drug used in pregnancy. A 32-year-old woman ingested 64 g of acetaminophen at 15 weeks of gestation. Treatment with N-acetylcysteine was given within 24 hours. The patient nonetheless developed severe hepatic necrosis and her hospital course was complicated by adult respiratory distress syndrome. With aggressive supportive treatment, the mother survived and delivered a viable infant at 32 weeks' gestation. The possible mechanisms of acetaminophen toxicity in the mother and the fetus are discussed.

Acetaminophen↗
PubMed1986

Neural tube defects: issues in prenatal diagnosis and counselling.

Neural tube defects are a heterogeneous group of malformations resulting from failure of neural tube closure during early embryogenesis. They range widely in severity from the lethal condition of anencephaly, to severely disabling meningomyeloceles, to completely surgically correctable meningoceles. Occurring in 1.4 to 1.6 per 1000 live births, neural tube defects rank second only to cardiac abnormalities as a cause of major congenital malformations in the United States. Technical developments over the past decade have enabled better detection of these conditions prenatally. Understanding of the etiology, neonatal treatment, and potential prevention of neural tube defects is increasing. Further, the ethical issues of treatment and screening are being widely discussed in both news magazines and the Congressional Record. Thus, it is timely to review this important area of prenatal counselling, diagnosis, and management.

Acetylcholinesterase↗
PubMed1985

The effect of oral ritodrine therapy on glucose tolerance in pregnancy.

Intravenous ritodrine therapy can cause significant deterioration of maternal glucose homeostasis. We investigated the effect of full maintenance oral ritodrine therapy (120 mg/day) on glucose tolerance in the early third trimester with the use of 50 gm 1-hour screens followed by 100 gm 3-hour oral glucose tolerance tests if the screen level was greater than or equal to 140 mg/dl. Four hundred ninety-one patients were studied, 42 of whom were receiving oral ritodrine therapy. Twenty-one percent of the ritodrine-treated women had an abnormal 1-hour screen, which was not different from the 20% observed in women not receiving therapy. None of the treated group and 13% of the untreated group who had abnormal screens had abnormal oral glucose tolerance tests. The probability of an abnormal test after an abnormal 1-hour screen was also determined.

Administration, Oral↗
PubMed1985

Can preterm deliveries be prevented?

Our hospital serves poor, inner-city women who have a 17% preterm delivery rate. Middle-class women in San Francisco at high risk for preterm delivery have benefited from an antepartum program which emphasized patient education and close follow-up. Using a controlled, randomized design, we are investigating the impact of similar interventions. Patients determined to be at high risk before 18 weeks' gestation on the basis of the Creasy system are randomly assigned to the Preterm Labor Prevention Clinic or serve as high-risk controls. Sixty-four women assigned to the Preterm Labor Prevention Clinic and 68 high-risk control women have been delivered of their infants. No significant differences were noted for the percentages of preterm infants, mean gestational age, or birth weight. Preterm rupture of the membranes accounted for 40% of preterm deliveries in all high-risk patients. Thirty percent of preterm births were indicated for maternal or fetal reasons. The remaining 30% represented failure of tocolytic therapy.

Birth Weight↗
PubMed1985

Epithelial jaw cysts: 10 years of the WHO classification.

Numerous papers on epithelial jaw cysts have appeared in the decade since the publication in 1971 of the WHO histological classification of odontogenic tumours, jaw cysts, and allied lesions. Despite clarification of certain cyst varieties no major revisions are necessary. The following minor modifications are proposed. In the developmental odontogenic group, the terms keratocyst and follicular are preferred to primordial and dentigerous. The alveolar cyst of infants is categorised separately from the gingival cyst of adults. The developmental lateral periodontal cyst is included as a distinctive new type. In the non-odontogenic group the globulomaxillary is deleted as a unique entity, whereas the midpalatal cyst of infants is a new inclusion. To the inflammatory category are added the inflammatory follicular and inflammatory lateral periodontal varieties.

Adult↗
PubMed1985

Compensatory increase in alpha 1-globin gene expression in individuals heterozygous for the alpha-thalassemia-2 deletion.

alpha-Globin is encoded by the two adjacent genes, alpha 1 and alpha 2. Although it is clearly established that both alpha-globin genes are expressed, their relative contributions to alpha-globin messenger RNA (mRNA) and protein synthesis are not fully defined. Furthermore, changes that may occur in alpha-globin gene activity secondarily to the loss of function of one or more of these genes (alpha-thalassemia [Thal]) have not been directly investigated. This study further defines the expression of the two human alpha-globin genes by determining the relative levels of alpha 1 and alpha 2 mRNA in the reticulocytes of normal individuals and in individuals heterozygous for the common 3.7-kilobase deletion within the alpha-globin gene cluster that removes the alpha 2-globin gene (the rightward type alpha-Thal-2 deletion). To quantitate accurately the ratio of the two alpha-globin mRNAs, we have modified a previously reported S1 nuclease assay to include the use of 32P end-labeled probes isolated from alpha 1- and alpha 2-globin complementary DNA recombinant plasmids. In individuals with a normal alpha-globin genotype (as determined by Southern blot analysis [alpha alpha/alpha alpha]), alpha 2-globin mRNA is present at an average 2.8-fold excess to alpha 1. In individuals heterozygous for the rightward type alpha-Thal-2 deletion (-alpha/alpha alpha) the alpha 2/alpha 1 mRNA ratio is 1:1. These results suggest that the loss of the alpha 2-globin gene in the alpha-Thal-2 deletion is associated with a 1.8-fold compensatory increase alpha 1-globin gene expression.

Chromosome Deletion↗
PubMed1983

Cesarean section versus vaginal delivery for the breech fetus weighing less than 1,500 grams.

Although previous studies have suggested that the breech infant weighing less than 1,500 gm benefits from cesarean section, the published results have not demonstrated statistically significant differences. We have evaluated pediatric outcome data for 240 breech infants and 525 vertex infants who weighed less than 1,500 gm, to determine whether route of delivery affects infant morbidity and mortality. Twenty-nine percent of these very small breech infants who were delivered by cesarean section died, as compared to 58% of breech infants of similar weight who were delivered vaginally (p less than 0.001). Comparable significant differences were found for the infants delivered at a university hospital as well as for those delivered at a group of nonuniversity hospitals. Apgar scores and the incidence and severity of intraventricular hemorrhage were not different for the cesarean section and vaginally delivered breech infants. Furthermore, the survival rate of the breech infants delivered by cesarean section equaled that of the vertex infants delivered either by cesarean section or vaginally.

Apgar Score↗
PubMed1983

Treatment of chloroquine-resistant malaria during pregnancy.

A pregnant 36-year-old Vietnamese refugee with chloroquine-resistant Plasmodium falciparum infection was treated with pyrimethamine and a sulfonamide. This treatment produced rapid clearance of the patient's parasitemia and was associated with a resumption of normal fetal and uterine growth. Because the other drugs effective against chloroquine-resistant P falciparum may produce uterine stimulation (quinine sulfate) or damage the fetal skeleton (tetracyclines), the pyrimethamine-sulfonamide combination (with folinic acid supplementation) may be the best available choice for the treatment and prophylaxis of chloroquine-resistant P falciparum infection in pregnancy, despite its theoretical risk of teratogenicity.

Adult↗
PubMed1983

Health effects of low-level exposure to formaldehyde.

Twenty-one subjects exposed to formaldehyde (at levels between 0.12 and 1.6 parts per million [ppm]) in two mobile trailers and the remaining 18 unexposed workers of the same workforce were examined by questionnaire and spirometry. Symptoms of eye and throat irritation and increased headache and fatigue were significantly more common among the exposed group than the comparison group. Irritation of the nose, chest tightness, and shortness of breath were also more common among the exposed. Spirometry revealed no decrease in ventilatory function among the exposed workers. The significant increase in frequency of individuals with symptoms indicated an adverse health effect from exposure to formaldehyde at levels between 0.12 and 1.6 ppm. This may have implications regarding the adequacy of the US permissible exposure limit value and suggests the need for further examination of the health effects of formaldehyde in the nonoccupational environment.

Adult↗
PubMed1982

Accelerated loss of FEV- in polyurethane production workers: a four-year prospective study.

A four-year longitudinal study of ventilatory function in polyurethane-foam production workers exposed to toluene diisocyanate (TDI) revealed a dose-response relationship between average exposure to TDI and change in forced expiratory volume per second (FEV-1). Workers with mean exposure in excess of 0.0035 ppm showed a greater rate of decline of FEV-1 over the four-year period than that expected from aging. Factors other than TDI exposure (sex, smoking history, history of atopy) do not account for the loss. The current threshold limit value (TLV) for exposure to TDI in industry (0.02 ppm) does not protect workers from accelerated impairment of ventilatory capacity.

Cyanates↗