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Biomedical subjects

Michael Dunn

Publications and source records attributed to Michael Dunn.

9 recordsLinked to original sources
PubMed2006

Economics of home vs. hospital breastfeeding support for newborns.

AIM: This paper presents the findings of research comparing the incremental costs associated with the provision of home-based vs. hospital-based support for breastfeeding by nurse lactation consultants for term and near-term neonates during the first week of life. BACKGROUND: A consequence of both consumer demands and increasing health resource constraints is that alternative care delivery models for safe, efficacious and cost-effective breastfeeding programmes have steadily evolved. To date, the economic impact of the setting (home or hospital) where lactation support is delivered has received little research attention. METHODS: Mother-infant dyads were stratified by gestational age as term (>37 weeks gestational age; n = 101) or near term (35-37 weeks gestational age; n = 37) and randomized to standard hospital care and postpartum follow-up (standard care), or to standard hospital care plus home support from certified nurse lactation consultants (experimental). Data collection occurred at study entry, hospital discharge and at a seventh day postpartum follow-up session. Costs to the family (out-of-pocket and time costs) and to the healthcare system (during hospitalization and after hospital discharge) were measured. Total societal costs were defined as the sum of both family and healthcare system costs. RESULTS: Compared with standard hospital-based care, home support by nurse lactation consultants showed no statistically significant differences in either time costs to the family or total societal costs. Term infants who received home support had statistically significantly greater postdischarge system costs (P < 0.0001), with a trend towards lower out-of-pocket expenses to their families (P = 0.12). There were no statistically significant differences between the two groups in overall combined family and healthcare system costs. CONCLUSIONS: These results suggest that the cost of home lactation support programmes were comparable with the costs of hospital-based standard care. Breastfeeding support at home by lactation consultants should be considered as an option as it was no more costly than support from lactation consultants in the hospital setting. The findings for near-term infants need to be interpreted with caution, given the small sample size.

Adult↗
PubMed2006

Postnatal growth failure in preterm infants: ascertainment and relation to long-term outcome.

OBJECTIVE: Traditional measure of postnatal growth failure assessment has poor discriminatory power for long-term outcomes. Our objective was to identify measure of postnatal growth failure associated with long-term outcome in preterm infants born at < 28 weeks' gestation. PATIENTS AND METHODS: Four measures of defining postnatal growth failure at 36 weeks corrected gestational age: (1) weight < 10(th) centile, (2) weight < 3(rd) centile, (3) z score difference from birth > 1 and, (4) z score difference from birth > 2; were compared for their predictive values and strength of association with adverse neurodevelopmental outcomes at 18-24 months. RESULTS: Postnatal growth failure defined as a decrease in z score of > 2 between birth and 36 weeks corrected gestational age had the best predictive values compared to other postnatal growth failure measures, however, it was significantly associated with psychomotor developmental (P=0.006) but not with mental developmental indices (P=0.379). CONCLUSION: Postnatal growth failure defined by z score change influenced psychomotor but not mental tasks in this cohort. This method of ascertainment could be useful to identify infants who might benefit from nutritional interventions.

Gestational Age↗
PubMed2005

Structural phylogenetics and the reconstruction of ancient language history.

The contribution of language history to the study of the early dispersals of modern humans throughout the Old World has been limited by the shallow time depth (about 8000 +/- 2000 years) of current linguistic methods. Here it is shown that the application of biological cladistic methods, not to vocabulary (as has been previously tried) but to language structure (sound systems and grammar), may extend the time depths at which language data can be used. The method was tested against well-understood families of Oceanic Austronesian languages, then applied to the Papuan languages of Island Melanesia, a group of hitherto unrelatable isolates. Papuan languages show an archipelago-based phylogenetic signal that is consistent with the current geographical distribution of languages. The most plausible hypothesis to explain this result is the divergence of the Papuan languages from a common ancestral stock, as part of late Pleistocene dispersals.

Asia↗
PubMed2005

A role for the mouse 12/15-lipoxygenase pathway in promoting epithelial wound healing and host defense.

The surface of the eye actively suppresses inflammation while maintaining a remarkable capacity for epithelial wound repair. Our understanding of mechanisms that balance inflammatory/reparative responses to provide effective host defense while preserving tissue function is limited, in particular, in the cornea. Lipoxin A(4) (LXA(4)) and docosahexaenoic acid-derived neuroprotectin D1 (NPD1) are lipid autacoids formed by 12/15-lipoxygenase (LOX) pathways that exhibit anti-inflammatory and neuroprotective properties. Here, we demonstrate that mouse corneas generate endogenous LXA(4) and NPD1. 12/15-LOX (Alox15) and LXA(4) receptor mRNA expression as well as LXA(4) formation were abrogated by epithelial removal and restored during wound healing. Amplification of these pathways by topical treatment with LXA(4) or NPD1 (1 microg) increased the rate of re-epithelialization (65-90%, n = 6-10, p < 0.03) and attenuated the sequelae of thermal injury. In contrast, the proinflammatory eicosanoids, LTB(4) and 12R-hydroxyeicosatrienoic acid, had no impact on corneal re-epithelialization. Epithelial removal induced a temporally defined influx of neutrophils into the stroma as well as formation of the proinflammatory chemokine KC. Topical treatment with LXA(4) and NPD1 significantly increased PMNs in the cornea while abrogating KC formation by 60%. More importantly, Alox15-deficient mice exhibited a defect in both corneal re-epithelialization and neutrophil recruitment that correlated with a 43% reduction in endogenous LXA(4) formation. Collectively, these results identify a novel action for the mouse 12/15-LOX (Alox15) and its products, LXA(4) and NPD1, in wound healing that is distinct from their well established anti-inflammatory properties.

Animals↗
PubMed2004

Rapid sequential heart-cut multidimensional gas chromatographic analysis.

A method is described which allows the sequential fast analysis of heart-cuts taken during the first column elution of an essential oil sample in a multidimensional gas chromatography experiment. In this investigation, a relatively short, narrow bore capillary column is used in the second dimension, with fast cryogenic modulation permitting rapid delivery of cryofocussed heart-cuts into the second column of the multidimensional arrangement. In this implementation, the total analysis time on the second column is of the order of 30 s, which is less than the duration of the sampled heart-cuts (1 min), with peak theoretical efficiencies of about 7000 m(-1). Thus, the method should allow on-line heart-cutting of as many discrete heart-cuts as one may require from the first dimension chromatogram, and so two-dimensional separation can be achieved for almost the whole sample in one single analysis without the need for repeat injections or cycling of the oven temperature. The method is demonstrated by the transfer and rapid re-injection of 1 min heart-cuts taken from an initial separation stage of peppermint essential oil. The cryofocussing and fast analysis step is shown to increase signal response by up to 40-fold. Total peak capacity in the described system is measured to be of the order of 1800, with capacities of about 20-30 for each 30 s second dimension analysis. By increasing the frequency of sampling to remove excessive (unused) time to develop the 2D separation, it should be possible to achieve peak capacities of 5000 or more baseline resolved peaks.

Chromatography, Gas↗
PubMed2004

Phenylalanine kinetics differ between formula-fed and human milk-fed preterm infants.

Infants fed casein-dominant formulas have higher plasma phenylalanine and tyrosine concentrations than those fed mother's milk. Conversely, elevated plasma threonine concentrations are observed in infants fed whey-dominant formulas. We recently showed that formula-fed preterm infants have a lower capacity to degrade threonine than do preterm infants fed mother's milk. We hypothesized that these same infants (n = 18) would differ in their catabolism of phenylalanine in response to phenylalanine loads provided by formulas with increasing casein content of formulas (whey:casein 60:40, 40:60, and 20:80) compared with preterm infants fed mother's milk. Plasma phenylalanine concentrations significantly rose (49, 46, 79 micromol . L(-1) for whey:casein 60:40, 40:60, and 20:80, respectively, pooled SD 8, P < 0.05); and plasma phenylalanine concentrations in infants fed mother's milk were low (40 +/- 4 micromol . L(-1)). Using [1-(13)C]phenylalanine tracer and (13)CO(2) production in breath we found that although there was a significant positive relation between phenylalanine oxidation and phenylalanine intake in formula-fed infants (r(2) = 0.43, P = 0.03), these infants were not able to increase their oxidation of phenylalanine enough to prevent a significant rise in plasma phenylalanine when fed the 20:80 formula. Compared to infants fed mother's milk, formula-fed infants had significantly lower phenylalanine oxidation (39.1 vs. 30.7% of phenylalanine intake, respectively, P < 0.05). We conclude that one of the mechanisms for the differences in plasma amino acid concentration between formula-fed and mother's milk-fed preterm infants may be in vivo down-regulated catabolism of 2 important essential amino acids (phenylalanine in addition to threonine) in formula-fed preterm infants.

Female↗
PubMed2003

Targeted multidimensional gas chromatography using microswitching and cryogenic modulation.

A new method is described that allows fast target analysis in multidimensional gas chromatography by using a microswitching valve between two GC columns, with cryogenic trapping and rapid re-injection of trapped solutes in the second dimension. The essence of the procedure is that heart-cut fractions from the first column (1D) can be selectively transferred to column 2 (2D), where a moveable cryogenic trap first focuses the transferred solute(s) at the head of the second column and then permits their facile rapid analysis on 2D. Since 2D is a short narrow-bore column, which exhibits very fast analysis (on the order of a few seconds elution), peak responses (heights) are significantly enhanced (by up to 40-fold). Additionally, by using a 2D phase of a selectivity different from that used for 1D, it is possible to also separate components that are not resolved on the first column and to increase the resolution for other compounds. The heart-cut valve isolates the section(s) of solutes of interest from the first column separation, and this provides a considerable simplification to the chromatogram-in addition to the separation and sensitivity advantages. By using this method, multidimensional gas chromatography with multiple heart-cuts can be completed within the same time as the primary column separation. Since the described method permits non-heart-cut fractions to be transferred to a monitor detector, normal detection of these fractions is still permitted. By modulation of the cryotrap, it is also possible to achieve comprehensive two-dimensional gas chromatography for the heart-cut fractions; however, only those compounds passed to the second, separation column, which passes through the cryotrap, will be subjected to GC x GC analysis. The technique and the various modes of operation are described in this paper.

Journal Article↗
PubMed2002

Increasing women's leadership in academic medicine: report of the AAMC Project Implementation Committee.

The AAMC's Increasing Women's Leadership Project Implementation Committee examined four years of data on the advancement of women in academic medicine. With women comprising only 14% of tenured faculty and 12% of full professors, the committee concludes that the progress achieved is inadequate. Because academic medicine needs all the leaders it can develop to address accelerating institutional and societal needs, the waste of most women's potential is of growing importance. Only institutions able to recruit and retain women will be likely to maintain the best housestaff and faculty. The long-term success of academic health centers is thus inextricably linked to the development of women leaders. The committee therefore recommends that medical schools, teaching hospitals, and academic societies (1) emphasize faculty diversity in departmental reviews, evaluating department chairs on their development of women faculty; (2) target women's professional development needs within the context of helping all faculty maximize their faculty appointments, including helping men become more effective mentors of women; (3) assess which institutional practices tend to favor men's over women's professional development, such as defining "academic success" as largely an independent act and rewarding unrestricted availability to work (i.e., neglect of personal life); (4) enhance the effectiveness of search committees to attract women candidates, including assessment of group process and of how candidates' qualifications are defined and evaluated; and (5) financially support institutional Women in Medicine programs and the AAMC Women Liaison Officer and regularly monitor the representation of women at senior ranks.

Career Mobility↗