Search PubMed⌕ Search

Biomedical subjects

E A Mitchell

Publications and source records attributed to E A Mitchell.

At least 55 records · Page 3Linked to original sources
PubMed2000

Previous breastfeeding does not alter thymic size in infants dying of sudden infant death syndrome.

The relationship between thymic weights and previous feeding histories was examined in 294 infants of 37 wk gestation or more dying of sudden infant death syndrome (SIDS). One hundred and sixty-five infants had been breastfed exclusively, 89 had been partially breastfed and 40 had never been breastfed. We found no relationship between thymic weight and type of previous feeding. The difference between these findings in SIDS and the substantially greater thymic size previously reported in 4-mo-old breastfed living infants deserves further study.

Age Factors↗
PubMed1999

Water fluoridation and the sudden infant death syndrome.

AIMS: To determine whether exposure to fluoridated water supplies prenatally or postnatally at the time of death increases the risk of sudden infant death syndrome (SIDS). METHODS: A nationwide, case-control study, with infant's water fluoridation status determined from census area unit information for mother's usual address at the time of the infant's birth, infant's usual address at the time of death / nominated sleep and address where infant died / was at nominated sleep. SIDS risk associated with fluoride exposure postnatally was assessed according to method of infant feeding (breast or reconstituted formula), for the two days prior to infant's death / nominated sleep. RESULTS: Infants exposed to fluoridated water supplies during pregnancy were not at increased risk for SIDS, adjusted odds ratio (OR) 1.19 (95% confidence interval (CI) 0.82, 1.74). For breast-fed infants at the time of death / nominated sleep, fluoridated water exposure was not associated with an increased risk for SIDS, adjusted OR 1.09 (95% CI 0.66, 1.79). Similarly, 'fluoridated' formula feeding, when compared with 'unfluoridated' formula feeding, showed no increased risk of SIDS, adjusted OR 1.25 (95% CI 0.73, 2.13). There was no evidence of an interaction between fluoridation and infant feeding for the last two days (chi2 = 0.171, df = 1, p = 0.68). CONCLUSION: Exposure to a fluoridated water supply prenatally or postnatally at the time of death did not affect the relative risk for SIDS.

Analysis of Variance↗
PubMed1999

Changing infants' sleep position increases risk of sudden infant death syndrome. New Zealand Cot Death Study.

OBJECTIVE: To examine whether the prone sleeping position may increase the risk for sudden infant death syndrome (SIDS), particularly in infants unused to prone sleep. DESIGN: A 3-year (1987-1990) case-control study. SETTING: Nationwide study in New Zealand. SUBJECTS: Four hundred eighty-five infants who died of SIDS and 1800 controls. MAIN OUTCOME MEASURES: Infants were classified as unaccustomed to prone if their usual sleep position was nonprone and they were placed prone for the last sleep. Secondary prone was used to describe infants placed nonprone but found prone. RESULTS: Infants usually and last placed nonprone were at the lowest risk for SIDS (odds ratio [OR], 1.0); those usually and last placed prone were at increased risk (adjusted OR, 4.6; 95% confidence interval, 3.4-6.3). Risk was greatly increased among infants unaccustomed to the prone position (adjusted OR, 19.3; 95% confidence interval, 8.2-44.8). These infants accounted for 8% (31/ 386) of all SIDS deaths. Ninety percent (28/ 31) of infants in this group were found prone, and 71% (20/28) of those found prone were found with their faces turned down into bedding-a position in which asphyxia has been implicated as a mechanism of death. In addition, 138 infants who died of SIDS were last placed nonprone. Forty-seven infants (34%) in this group were found prone (secondary prone), and 60% (28/47) of those found prone were found with their faces turned down into the bedding. This group accounted for 12% of all SIDS deaths. Most of these infants (91% [43/47]) were usually placed nonprone. CONCLUSIONS: Infants placed supine to sleep were at the lowest risk of SIDS, which supports the recommendation that this is the preferred sleeping position for healthy infants. In New Zealand, 20% of SIDS deaths involved lack of experience with the prone sleeping position. Our findings suggest the possibility that an infant's competence in escaping from potentially lethal situations during prone sleep (eg, the face-down position) may be impaired by inexperience in prone sleeping. Great caution should be exercised in placing infants unaccustomed to the prone sleeping position in the prone position.

Case-Control Studies↗
PubMed1999

Mastitis in the first year postpartum.

BACKGROUND: Limited information is available about the frequency and risk factors for lactation mastitis. The purpose of this study was to investigate frequency, risk factors, and outcome for lactation mastitis. METHODS: We analyzed data from a cohort study of 350 mothers with healthy term infants, who were followed up for one year postpartum. RESULTS: Eighty-three women (23.7% of the sample) reported one or more episodes of mastitis symptoms, and 61 (17.4%) women reported symptoms including fever. Fifty-six women (16%) received one or more courses of antibiotics for mastitis. Thirty women (8.5%) of the total cohort had recurrent episodes of mastitis symptoms. A total of 123 episodes of mastitis symptoms were reported. No cases of abscess were reported. Using multiple logistic regression, the adjusted risk ratio for mastitis symptoms associated with sore nipples in the first month was 2.07 (95% CI = 1.17, 3.66). A reduced risk of mastitis was associated with maternal smoking during pregnancy, with supplementation with water in the first month, and with the use of a pacifier on a daily basis within the first month. A history of mastitis symptoms was associated with a longer overall duration of breastfeeding. CONCLUSIONS: Our results suggest that mastitis may be a marker for an ample milk supply. Mothers presenting with mastitis can be reassured that the outlook for continued successful lactation is good. Further research is needed to investigate the reasons for recurrence of mastitis and the etiology of episodes occurring late in lactation.

Adult↗
PubMed1999

Seasonal differences in risk factors for sudden infant death syndrome. The New Zealand Cot Death Study Group.

The aim of this study was to explore whether the risk of sudden infant death syndrome (SIDS) associated with prone sleeping position and other risk factors varies with season. The study was a large nation-wide case-control study, which compared 485 cases with 1800 controls. Parents of 393 (81.0%) cases and 1591 (88.4%) controls were interviewed. Obstetric records were also examined. Infants dying in winter were older and had lower birthweights than those dying in summer. The increased risk of SIDS associated with prone sleeping position was greater in winter than in summer. In contrast, the increased risk of SIDS associated with excess thermal insulation and bed sharing was less in winter than in summer. Prone sleeping position accounts for about half of the difference between the mortality rate in summer and that in winter. This suggests that some factor related to season modifies the effect of prone sleeping position.

Age Distribution↗
PubMed1999

Factors associated with the duration of breastfeeding.

A cohort study of healthy term infants was conducted to identify factors associated with breastfeeding duration. Three hundred and fifty mothers delivering in one obstetric hospital in Auckland, New Zealand were recruited. Ninety-five percent were followed up until 1 y. Breastfeeding was initiated by 97.4%, the median duration of breastfeeding was 7.6 mo, and 30% were continuing some breastfeeding at 12 mo. Adjusted risk ratios for shorter duration of breastfeeding were: maternal age <25 y, 2.33 (95% confidence interval = 1.33, 4.05); maternal age 25-34, 1.45 (1.01, 2.09) compared to maternal age > or =35; planning to cease breastfeeding < or =6 mo, 2.39 (1.65, 3.46); planning to breastfeed for as long as possible, 1.48 (1.00, 2.18), or not knowing plans 2.13 (1.36, 3.32) when compared to planning to cease breastfeeding after 6 mo; inverted nipples, 2.02 (1.26, 3.23), daily dummy use 1.62 (1.20, 2.18) or use of formula in the first month 2.79 (2.05, 3.80). Reporting mastitis, 0.67 (0.48, 0.94), and sharing the mother's bedroom at 3 mo, 0.69 (0.51, 0.92) were associated with a reduced risk for shorter duration of breastfeeding. We recommend that during the antenatal period attention be directed at mothers' plans for duration of breastfeeding, that mothers be encouraged to have their baby in their bedroom, and that the use of formula and dummies should be discouraged in the first months of life.

Adult↗
PubMed1999

Use of duvets and the risk of sudden infant death syndrome.

BACKGROUND: The use of duvets in infancy is not recommended in the UK and Australia because of a reported association with sudden infant death syndrome (SIDS). AIMS: To examine the association between the use of duvets and the risk of SIDS. METHODS: A nationwide case control study (393 cases, 1592 controls). The use of duvets was assessed by interview with the parent or guardian. RESULTS: The use of duvets was associated with an increased risk of SIDS (odds ratio (OR) = 1.65; 95% confidence interval (CI), 1.31 to 2.08); however, after adjustment for potential confounders there was no increased risk of SIDS (OR = 1.04; 95% CI, 0.77 to 1.38). Furthermore, subgroup analysis did not identify any group in which the use of duvets was associated with an increased risk of SIDS. CONCLUSIONS: This study does not support the recommendation to avoid duvets.

Bedding and Linens↗
PubMed1999

Resistance to Friend leukemia virus in transgenic mice expressing the native Fv-4 gene.

Fv-4 is a truncated ecotropic retrovirus gene that codes for an envelope protein under control of a cellular promoter. It confers resistance to ecotropic murine leukemia viruses. Transgenic mice were derived using the native Fv-4 gene as the construct for microinjection. Two founder mice were derived. In both founder lines, there was no detectable expression of the transgene or resistance to Friend murine leukemia virus (FrMLV) in hemizygotes. In one line, the resistance was observed in homozygotes with Fv-4 RNA formation in the thymus but not in the spleen or in other tissues. In the other founder line, a homozygous male was identified. Double integrants, derived from breeding this homozygous male to homozygous females from the other founder line, were also resistant. These results indicate that the native gene confers the resistance in homozygous transgenic mice or double integrants derived from different founders but not hemizygotes.

Animals↗
PubMed1998

Antibody-secreting cells specific for simian immunodeficiency virus antigens in lymphoid and mucosal tissues of immunized macaques.

OBJECTIVES: To examine whether the route of immunization affects the induction of antibody-secreting cells (ASC) in the circulation of macaques. The distribution of ASC in the rectal mucosa and lymphoid tissues following challenge with simian immunodeficiency virus (SIV) was investigated. DESIGN: Macaques were immunized with recombinant SIV gp120 and p27 antigens by the targeted iliac lymph node (TILN) route of immunization or the nasal and rectal route, augmented by intramuscular immunization [naso-rectal intramuscular (NRI)]. The macaques were challenged with live SIV by the rectal route and ASC were assayed in the circulation before and after SIV challenge, and in the tissues removed at post-mortem. METHODS: ASC were examined in the circulation by Elispot assay. Mononuclear cells were prepared from peripheral blood, iliac and axillary lymph nodes and spleen. Rectal tissue was treated by enzyme digestion to elute mononuclear cells. RESULTS: TILN and NRI immunization induced circulating IgA and IgG ASC to both gp120 and p27. Following rectal challenge with SIV, TILN macaques were protected from infection whereas NRI route-immunized and unimmunized controls became infected. IgA ASC to p27 were increased significantly in the iliac lymph nodes of the TILN immunized macaques compared with unimmunized controls (P < 0.05). Only IgA ASC were found in the rectal mucosa of the immunized protected macaques but both IgA and IgG ASC were detected in the unimmunized infected macaques. Overall the number of IgG ASC specific for p27 was significantly higher in the infected NRI and control macaques than in the protected macaques (P < 0.02). A progressive increase in IgG but not IgA ASC was detected in the peripheral blood mononuclear cells of the unimmunized infected macaques. CONCLUSIONS: The results suggest that cells secreting IgA antibodies to p27 in the iliac lymph nodes of the TILN immunized macaques correlate significantly with protection from infection. The unimmunized infected macaques showed a progressive increase in IgG ASC in the peripheral blood after SIV challenge; this was found in the iliac and axillary lymph nodes and also in the spleen, suggesting that it is an immune response to the SIV infection.

Administration, Intranasal↗
PubMed1998

Risk factors for preterm birth: a New Zealand study.

AIM: To identify risk factors for preterm birth. METHODS: A cross sectional study. The study population was 1800 infants selected randomly from all babies born over a three-year period. Of these, 85 (4.8%) were classified preterm (less than 37 completed weeks gestation). Data were collected from obstetric records and parental interviews. RESULTS: Risk factors associated with an increased risk of preterm birth after controlling for potential confounders included smoking during pregnancy (adjusted relative risk (RR) = 2.7, 95% confidence interval (CI) = 1.3, 5.4), and multiple birth (adjusted RR = 48.8, 95% CI = 18.1, 131.4). Urinary tract infection was significant at the 7% level (adjusted RR = 2.3, 95% CI = 1.0, 5.6). Alcohol intake in third trimester was associated with a reduced risk of preterm birth (adjusted RR = 0.4, 95% CI = 0.2, 0.7). CONCLUSION: Maternal smoking and multiple births were the most important modifiable risk factors in this study for preterm birth and may contribute to 17% and 11% of preterm births respectively.

Cross-Sectional Studies↗
PubMed1998

Homing of mononuclear cells from iliac lymph nodes to the genital and rectal mucosa in non-human primates.

The route of immunization may affect the type of immunity that is induced. The objectives of this investigation were to establish in the non-human primate if the internal iliac lymph nodes (LN) function as an inductive site of immunity from which mononuclear cells home to the rectal and cervico-vaginal mucosa. Rhesus macaques were immunized with simian immunodeficiency virus (SIV) core antigen p27 in the proximity of the iliac lymph nodes, and compared with the intramuscular (i.m.) (deltoid or gluteal), and axillary LN routes of immunization. The macaques were then challenged rectally or vaginally by a particulate SIVp27 antigen which was applied to the mucosal surface. The tracking dye PKH26 was injected near the immunizing LN or i.m. site and a week later the mucosal and lymphoid tissues were examined at autopsy. Preferential homing of PKH26-labeled cells from the internal iliac LN to the rectal and vaginal mucosa was demonstrated by flow cytometry after targeted iliac LN (TILN) but not after intramuscular (deltoid) or axillary LN immunization. Homing of the subsets of cells revealed that labeled CD4, CD8 and B cells, as well as monocytes were found in the rectum, colon, vagina or cervix. The results of this investigation shows that the route of immunization may affect regional mucosal immunity. Furthermore, the internal iliac LN may function as an inductive immunological site from which CD4, CD8 and B cells may home preferentially to the rectal, cervical and vaginal mucosa, as well as to the related regional but not the unrelated distal LN.

Animals↗
PubMed1998

Sheepskin bedding and the sudden infant death syndrome. New Zealand Cot Death Study Group.

We carried out a nationwide case-control study, comparing 393 case patients with sudden infant death syndrome (SIDS) with 1592 control subjects, in order to examine sheepskin bedding as a risk factor. Sheepskin use was similar for case patients and control subjects (both, 42%; adjusted odds ratio [OR] = 1.28; 95% CI = 0.92, 1.79). Sheepskin use among the control subjects was associated with socioeconomic advantage. The relative risk for SIDS with sheepskin use was significantly increased in the infants placed prone to sleep (adjusted OR = 1.70; 95% CI = 1.08, 2.67), but not for infants placed in the supine or lateral position (adjusted OR = 0.82; 95% CI = 0.45, 1.48). An interaction between sheepskin use and bed sharing was also found. Sheepskin use was associated with a decreased risk of SIDS among infants sharing beds (adjusted OR = 0.61; 95% CI = 0.38, 0.99), but an increased risk among infants not bed sharing (adjusted OR = 2.25; 95% CI = 1.32, 3.86). We conclude that if an infant needs to be placed prone to sleep for medical reasons, a sheepskin should not be used as underbedding. However, for infants placed supine to sleep, sheepskins are not associated with an increased risk of SIDS.

Animals↗
PubMed1998

Residential mobility and sudden infant death syndrome.

OBJECTIVE: To examine whether permanent domicile change of the mother, thence the infant, or temporary relocation of the infant away from his or her usual place of residence affects the risk of sudden infant death syndrome (SIDS). DESIGN: A case-control nation-wide epidemiological study. SETTING: New Zealand between the years 1987-90. PARTICIPANTS: From the 485 SIDS diagnoses over this time, parents of 393 (81%) SIDS infants consented to participate and these comprise the cases. Controls were selected by randomly sampling 1800 infants from all babies born over 78% of the country. Parents of 1592 (88%) control infants participated. RESULTS: Infants away from their usual address were 1.70 (95% CI: 1.09, 2.66) times more likely to die from SIDS than infants sleeping at home, after controlling for likely confounding factors. A partial explanation for this finding was that SIDS infants were less likely to have been mainly breast fed in the last two days and were less likely to have shared a room with at least one adult at the nominated sleep/death. Infants of mothers who shifted house after their birth, infants having mothers who shifted house within a year prior to the study interview date, and infants who slept at numerous different houses were associated with an increased relative risk for SIDS at the univariate level, but not after adjustment. CONCLUSIONS: Infants are less likely to die in their accustomed residential environment. This finding needs confirmation by other studies.

Adult↗
PubMed1998

Heavy caffeine intake in pregnancy and sudden infant death syndrome. New Zealand Cot Death Study Group.

AIMS: To examine the association between maternal caffeine consumption during pregnancy and the risk of sudden infant death syndrome (SIDS). METHODS: A nationwide case-control study surveying parents of 393 SIDS victims and parents of 1592 control infants. Caffeine consumption in each of the first and third trimesters was estimated by questionnaire. Heavy caffeine intake was defined as 400 mg/day or more (equivalent to four or more cups of coffee per day). RESULTS: Infants whose mothers had heavy caffeine consumption throughout their pregnancy had a significantly increased risk for SIDS (odds ratio 1.65; 95% confidence interval 1.15 to 2.35) after adjusting for likely confounding factors. CONCLUSION: Caffeine intake has been associated with fetal harm and now SIDS. Reducing heavy caffeine intake during pregnancy could be another way to lessen the risk of SIDS. This needs confirmation by others.

Caffeine↗