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Biomedical subjects

A A Mitchell

Publications and source records attributed to A A Mitchell.

At least 55 records · Page 3Linked to original sources
PubMed1994

Total bilirubin level in relation to excipients in parenteral morphine sulfate administered to seriously ill newborn infants.

We examined exposure to excipients in different morphine sulfate preparations in relation to maximum total bilirubin level during the first 5 days of life among 155 infants admitted to a newborn intensive care unit. Sixty-six (43%), 47 (30%), and 42 (27%) newborns were exposed to chlorobutanol, phenol and neither excipient, respectively. Mean maximum total bilirubin in the first 5 days of life among newborns not exposed to chlorobutanol or phenol was 10.8 mg/dL (184 mumol/L). After adjusting for birthweight, race, sex, and use of phototherapy, the maximum total bilirubin level among newborns exposed to phenol was 1.4 mg/dL (24 mumol/L) higher than the maximum level among newborns exposed to neither excipient (P < 0.05); the corresponding difference associated with chlorobutanol exposure was 1.6 mg/dL (27 mumol/L) (P < 0.02). Further adjustment for potential confounding by the major risk factors for hyperbilirubinaemia did not materially change the results. While unconfirmed, these findings support the growing concern that excipients added to parenteral medications may not be 'inactive' as is often assumed, and that the safety of such exposures in seriously ill newborn infants needs to be studied further.

Bilirubin↗
PubMed1993

Periconceptional folic acid exposure and risk of occurrent neural tube defects.

OBJECTIVES: A recent controlled trial has established that use of a 4-mg folic acid supplement before and during early pregnancy reduces the risk of recurrent neural tube defects (NTDs) by 72%. The present study was designed to determine whether folic acid also reduces the risk of first (occurrent) NTDs. DESIGN: Case-control study. SETTING: Tertiary and birth hospitals in metropolitan areas of Boston, Mass, Philadelphia, Pa, and Toronto, Ontario. PARTICIPANTS: Mothers of 436 occurrent cases with NTDs and mothers of 2615 controls with other major malformations. MAIN OUTCOME MEASURES: The prevalence of use of multivitamins containing folic acid was compared between mothers of cases and controls. RESULTS: The mothers of 17% of cases and 3% of controls reported knowledge of the folic acid-NTD hypothesis and were excluded from further analysis. For daily use of a multivitamins containing folic acid in the periconceptional period (28 days before through 28 days after the last menstrual period), the relative risk (RR) (and 95% confidence interval) was 0.4 (0.2 to 0.6). The most commonly used dose of folic acid was 0.4 mg, and the RR estimate was 0.3 (95% confidence interval, 0.1 to 0.6). For dietary folate, there was a dose-related decline in risk according to the quintile of intake (P for trend = .02). CONCLUSION: These findings suggest that daily periconceptional intake of 0.4 mg of folic acid (the dose most commonly contained in over-the-counter multivitamin preparations) reduces the risk of occurrent NTDs by approximately 60%. A relatively high dietary intake of folate may also reduce the risk.

Case-Control Studies↗
PubMed1992

Demographic, reproductive, medical, and environmental factors in relation to gastroschisis.

To identify risk factors for gastroschisis other than drug use in pregnancy, an analysis of data collected in a case-control surveillance program of birth defects (1976-1990) was conducted. Drug use is considered in Werler et al., Teratology, 45:361-367, 1992. Maternal demographic, reproductive, and medical factors, and first trimester environmental exposures, were compared between 76 gastroschisis cases and 2,581 malformed controls. A strong inverse association was found for maternal age: relative to women 30 years or older, relative risks for 25-29, 20-24, and less than 20-year-old women were 1.7, 5.4, and 16, respectively. Multivariate relative risks (and 95% confidence intervals) for alcohol use were as follows: for 1-5 drinks per week, 1.6 (0.7-3.4); for greater than or equal to 6 drinks per week, 2.5 (0.9-6.8); for a maximum of 1-4 drinks at any one time, 0.8 (0.4-1.6); and for a maximum of greater than or equal to 5 drinks, 2.8 (1.2-6.5). With the effect of age taken into account, no associations were identified for cigarette smoking, consumption of caffeinated or decaffeinated coffee, unplanned pregnancy, 12 or less years of education, or a parity of two or more. Other medical and reproductive factors, including weight gain, vaginal bleeding, nausea or vomiting, influenza, "other" infection, and history of spontaneous abortion or elective abortion did not increase the risk.

Abdominal Muscles↗
PubMed1992

First trimester maternal medication use in relation to gastroschisis.

In a case-control surveillance program, first trimester medication use was studied in relation to gastroschisis. There were 76 cases of gastroschisis which were compared with 2,142 controls with other major malformations. For pseudoephedrine use, we found a significantly elevated relative risk of 3.2 (95% confidence interval, 1.3-7.7), with adjustment for confounding. Multivariate relative risks for analgesic/antipyretics and another decongestant were as follows: salicylates, 1.6 (0.9-2.7); acetaminophen, 1.7 (1.0-2.9); ibuprofen, 1.3 (0.4-3.7); and phenylpropanolamine, 1.5 (0.4-5.4). No increases in risk were identified for use of antihistamines, antibiotics, oral contraceptives, or spermicides. Because salicylates, pseudoephedrine, and phenylpropanolamine are vasoactive, the elevated risks for these drugs support the hypothesis of vascular disruption in the etiology of gastroschisis. We therefore examined maternal use of vasoactive medications in relation to a second case group of 416 infants with hetereogeneous defects suspected to have a vascular etiology. Relative risks for salicylates, ibuprofen, pseudoephedrine, phenylpropanolamine, and other decongestants approximated unity. These positive associations must be considered tentative. They have not been reported previously and should be confirmed independently. Also, acetaminophen, which may be taken for the same indications as salicylates and decongestants, but is not thought to be vasoactive, was associated with gastroschisis, suggesting that identified associations may be due to an underlying maternal illness.

Abdominal Muscles↗
PubMed1991

Maternal alcohol use in relation to selected birth defects.

The hypothesis that maternal alcohol consumption affects the development of structures possibly derived from a common embryonic cell population, the cranial neural crest, was explored using data collected by a case-control surveillance program of birth defects in greater Boston, Philadelphia, and Toronto, Ontario, Canada, and in five counties in Iowa from 1983 through 1987. Maximum and average alcohol consumption during the first four lunar months of pregnancy were compared between the mothers of 1,464 infants with malformations of the ear, face, anterior neck, and upper heart (cranial neural crest cases) and 1,427 infants with other malformations (controls). For maximum number of drinks in a day and average number of drinking days per week, relative risks approximated unity across levels of exposure. For average number of drinks per drinking day, the relative risk (and 95% confidence interval) for heavy intake (5 or more drinks) was 1.8 (0.8-4.4). When the largest defect subgroup of cases, infants with cleft lip with or without cleft palate, was considered separately, the relative risk for an average of 5 or more drinks per drinking day was 3.0 (1.1-8.5). These findings suggest that maternal alcohol use is less related to overall malformations derived from cranial neural crest cell than to one specific defect among them--cleft lip with or without cleft palate. However, the latter association has not been reported previously in humans and remains to be confirmed in other studies.

Abnormalities, Drug-Induced↗
PubMed1990

Maternal vitamin A supplementation in relation to selected birth defects.

High doses of vitamin A cause birth defects in animals. Concern over vitamin A teratogenicity in humans has been prompted by reports of teratogenic effects of the vitamin A analogue, isotretinoin. The pattern of defects observed among isotretinoin- and vitamin A-exposed infants and animals suggests a possible mechanism involving cranial neural crest cell activity. Data from a case-control study were used to assess maternal use of vitamin A supplements alone and vitamin A-containing multivitamin supplements in relation to the occurrence of certain birth defects involving structures derived, at least in part, from cranial neural crest cells. Cases were 2,658 infants with such defects (primarily craniofacial and cardiac malformations). Controls were 2,609 infants with other malformations. Vitamin A supplementation was defined as daily use for at least 7 days of retinol alone or with vitamin D, or of fish oils. Information on vitamin A dose and nutrition was not available. The mothers of six controls used vitamin A supplements in each of the first three lunar months of pregnancy in comparison to the mothers of 15, 14, and 10 cases in lunar months 1, 2, and 3, respectively. Relative risk estimates and 95% confidence intervals were 2.5(1.0-6.2) for lunar month 1, 2.3(0.9-5.8) for lunar month 2, and 1.6(0.6-4.5) for lunar month 3. These findings should be considered tentative because no dose information was available, small numbers of cases and controls were exposed to vitamin A supplements, and relative risk estimates were not statistically significant.(ABSTRACT TRUNCATED AT 250 WORDS)

Abnormalities, Drug-Induced↗
PubMed1990

Recent patterns of drug use in newborn intensive care.

To better understand patterns of medication use in neonatal intensive care, we examined data collected prospectively over a recent 9-year period in the newborn intensive care units of two large teaching hospitals. Among 2690 infants studied, 91% received at least one drug; 99% of infants weighing less than 1500 gm were exposed to drugs, compared with 90% of infants weighing more than 1500 gm. Among treated infants, the median number of drugs received was eight; the number of drugs administered was inversely related to birth weight and directly related to both length of hospital stay and the complexity of the infant's clinical condition. Within categories of length of hospital stay, the number of drugs received per day was greatest during the first week in the neonatal intensive care unit and fell to a relatively stable lower level during the second week. The most commonly used single drug was gentamicin (71% exposed), followed by sodium chloride (60%), potassium chloride (59%), heparin (58%), and packed erythrocytes (45%). Between 1978-1979 and 1985-1986 the prevalence of use increased substantially for some drugs (ampicillin, morphine, calcium salts, and acetates of sodium and potassium) and decreased for others (kanamycin, sodium bicarbonate, and blood products). These data document the dynamic nature of drug therapy in the neonatal intensive care unit and provide information that can guide cost-benefit assessments in this setting.

Anti-Bacterial Agents↗
PubMed1990

Maternal cigarette smoking during pregnancy in relation to oral clefts.

Studies on maternal smoking in relation to oral cleft defects have yielded inconsistent findings, with results ranging from no association to sixfold increases in risk. The authors examined this relation in a case-control study conducted in Boston, Massachusetts, Philadelphia, Pennsylvania, Toronto, Ontario, Canada, and the state of Iowa during the years 1983-1987, in which mothers of malformed infants were interviewed within 6 months after delivery about prenatal events and exposures. Maternal cigarette smoking during pregnancy for 400 infants with cleft lip with or without cleft palate and for 215 infants with cleft palate alone was compared with that for 2,710 infants with other malformations (controls). Relative risks (and 95% confidence intervals) were estimated for smokers of 1-14, 15-24, and greater than or equal to 25 cigarettes per day relative to never smokers; the respective estimates for cleft lip with or without cleft palate were 1.2 (95% confidence interval (CI) 0.9-1.6), 1.4 (95% CI 1.0-2.1), and 0.7 (95% CI 0.3-1.6), and for cleft palate alone, estimates were 1.0 (95% CI 0.7-1.5), 0.9 (95% CI 0.5-1.5), and 0.8 (95% CI 0.3-2.2). Relative risks were also close to unity for case subgroups divided according to the presence or absence of an associated malformation. Multivariate control of several potential confounders did not alter these estimates. Based on this large series of cases, maternal smoking during pregnancy does not appear to increase the risk of oral clefts.

Canada↗
PubMed1990

Hyperbilirubinemia following exposure to pancuronium bromide in newborns.

We investigated the risk of hyperbilirubinemia in relation to the administration of pancuronium bromide among newborn infants requiring mechanical ventilation. One hundred and twenty-nine infants treated with pancuronium were compared to 129 infants who were never exposed, matched on ventilatory status, hospital, birthweight, initial total serum bilirubin, and date of hospital discharge. Overall, the adjusted summary relative risk (RR) for hyperbilirubinemia among pancuronium-exposed infants compared to nonexposed infants was 1.2 (95% confidence interval 1.1-1.4). The risk was greatest among exposed infants during the 4 days following the last dose of pancuronium (RR = 1.4; 1.0-1.8). These data suggest that the use of pancuronium in sick newborns may be associated with an increased risk of clinically important hyperbilirubinemia.

Bilirubin↗
PubMed1989

The relation of aspirin use during the first trimester of pregnancy to congenital cardiac defects.

It has been hypothesized that the ingestion of aspirin by women during pregnancy increases their infants' risk of certain congenital heart defects. Using data from a large program of case-control surveillance of congenital malformations, we evaluated this hypothesis. The case groups were made up of infants with any structural cardiac defect (n = 1381) and five selected cardiac defects (the subgroups were not mutually exclusive): aortic stenosis (n = 43), coarctation of the aorta (n = 123), hypoplastic left ventricle (n = 98), transposition of the great arteries (n = 210), and conotruncal defects (n = 791). First-trimester aspirin use among the mothers of these infants was compared with that among the mothers of a control group of infants with other malformations (n = 6966). The prevalence of any maternal aspirin use was similar for cases (25 to 33 percent) and controls (27 percent). The relative risks (and 95 percent confidence interval) among infants whose mothers were aspirin users as compared with those whose mothers did not use aspirin, adjusted for potential confounding factors, were 0.9 (0.8 to 1.1) for any cardiac defect, 1.2 (0.6 to 2.3) for aortic stenosis, 1.0 (0.6 to 1.4) for coarctation, 0.9 (0.6 to 1.4) for hypoplastic left ventricle, 0.9 (0.6 to 1.2) for transposition of the great arteries, and 1.0 (0.8 to 1.2) for conotruncal defects. Furthermore, no dose-effect pattern was identified. The findings of this study indicate that aspirin use during the first trimester of pregnancy does not increase the risk of congenital heart defects in relation to that of other structural malformations.

Abnormalities, Drug-Induced↗
PubMed1988

Adverse drug reactions in children leading to hospital admission.

To provide information regarding pediatric hospital admissions prompted by adverse drug reactions, data were reviewed from an intensive drug surveillance program in which 10,297 patients admitted to diverse pediatric wards at four teaching and three community hospitals were systematically monitored. Among 3,026 neonatal intensive care unit admissions, 0.2% were prompted by adverse drug reactions; among 725 children with cancer, 22% of admissions were prompted by adverse drug reactions. Among 6,546 children with other conditions monitored on general medical and specialty wards at two teaching hospitals and on general pediatric wards at three community hospitals, 2% (131) of admissions were prompted by adverse drug reactions. Two patients (0.03%) died because of their reactions. The proportion of admissions prompted by drug reactions increased between infancy and 5 years of age and tended to be relatively stable thereafter. The drugs most commonly implicated in the admissions were phenobarbital, aspirin, phenytoin, ampicillin/amoxicillin, theophylline/aminophylline, trimethoprim-sulfamethoxazole, and diphtheria-pertussis-tetanus vaccine. Similar proportions of admissions were prompted by adverse drug reactions in teaching hospitals (2.1%) and in community hospitals (1.8%), and the drug groups implicated in these admissions were generally similar in the two settings. In contrast to adult populations, children with adverse drug reactions account for a small proportion of hospital admissions. Findings from this large, systematic study of pediatric admissions to teaching and community hospitals may serve as a baseline to which other pediatric facilities can compare their experience.

Adolescent↗
PubMed1987

Maternal exposure to spermicides in relation to certain birth defects.

Several studies have found no increase in the overall frequency of birth defects in association with the use of spermicides, but the possibility of an increase in specific defects remains. We evaluated this possibility in a large case-control study. Infants with certain malformations (265 with Down's syndrome, 396 with hypospadias, 146 with limb reduction defects, 116 with neoplasms, and 215 with neural-tube defects) were compared with 3442 control infants with a wide variety of other defects. Exposure to spermicides was assessed for three periods: use during the periconceptional period (one month before through one month after the last menstrual period), use during the first trimester (the first four lunar months of pregnancy), and any use during the lifetime. For the five groups of cases and for each interval, the odds ratios were close to 1.0 (range, 0.7 to 1.3); the upper 95 percent confidence bounds were 2.2 or lower. Risks did not increase with the duration of exposure. When each of the active ingredients in currently available spermicides was considered separately, no differences in odds ratios were apparent between the types of spermicides. With the possible exception of a subgroup of cases (limb reduction defects of unknown cause), these results suggest that risks for the five specific birth defects evaluated are not increased by exposure to spermicides.

Abnormalities, Drug-Induced↗