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Biomedical subjects

P E Hartmann

Publications and source records attributed to P E Hartmann.

At least 19 recordsLinked to original sources
PubMed2005

Analysis of feeding behavior with direct linear transformation.

AIM: The sucking pattern of term infants is composed of a rhythmic alteration of expression and suction movements. The aim is to evaluate if direct linear transformation (DLT) method could be used for the assessment of infant feeding. SUBJECT AND METHODS: A total of 10 gnormalh infants and two infants with neurological disorders were studied using DLT procedures and expression/suction pressure recordings. Feeding pattern of seven gnormalh infants were evaluated simultaneously recording DLT and pressures. The other infants were tested non-simultaneously. We placed markers on the lateral angle of the eye, tip of the jaw, and throat. The faces of infants while sucking were recorded in profile. The jaw and throat movements were calculated using the DLT procedure. Regression analysis was implemented to investigate the relationship between suction and expression pressures and eye-jaw and eye-throat movement. All regression analyses investigated univariate relationships and adjusted for other covariates. RESULTS: Ten gnormalh infants demonstrated higher suction pressure than expression pressure, and their throat movements were larger than jaw movements. Two infants with neurological problems did not generate suction pressure and demonstrated larger movements in their jaw than throat. The simultaneous measurement (n=7) showed a significant correlation, not only between eye-jaw distance and the expression pressure, but also between eye-throat distance and suction pressure. The change in the eye-jaw distance was smaller than the changes in the eye-throat distance in gnormalh infants (p<0.001). CONCLUSIONS: The DLT method can be used to evaluate feeding performance without any special device.

Humans↗
PubMed2005

Anatomy of the lactating human breast redefined with ultrasound imaging.

The aim of this study was to use ultrasound imaging to re-investigate the anatomy of the lactating breast. The breasts of 21 fully lactating women (1-6 months post partum) were scanned using an ACUSON XP10 (5-10 MHz linear array probe). The number of main ducts was measured, ductal morphology was determined, and the distribution of glandular and adipose tissue was recorded. Milk ducts appeared as hypoechoic tubular structures with echogenic walls that often contained echoes. Ducts were easily compressed and did not display typical sinuses. All ducts branched within the areolar radius, the first branch occurring 8.0 +/- 5.5 mm from the nipple. Duct diameter was 1.9 +/- 0.6 mm, 2.0 +/- 90.7 mm and the number of main ducts was 9.6 +/- 2.9, 9.2 +/- 2.9, for left and right breast, respectively. Milk ducts are superficial, easily compressible and echoes within the duct represent fat globules in breastmilk. The low number and size of the ducts, the rapid branching under the areola and the absence of sinuses suggest that ducts transport breastmilk, rather than store it. The distribution of adipose and glandular tissue showed wide variation between women but not between breasts within women. The proportion of glandular and fat tissue and the number and size of ducts were not related to milk production. This study highlights inconsistencies in anatomical literature that impact on breast physiology, breastfeeding management and ultrasound assessment.

Adipose Tissue↗
PubMed2004

The effect of supplementation with fish oil during pregnancy on breast milk immunoglobulin A, soluble CD14, cytokine levels and fatty acid composition.

BACKGROUND: Breast milk contains many immunomodulatory factors (soluble CD14 (sCD14), IgA and cytokines) with the potential to influence infant immune development. OBJECTIVE: To determine if changes in breast milk omega-3 polyunsaturated fatty acid (n-3 PUFA) composition as a result of maternal dietary fish oil supplementation during pregnancy can modify levels of these immunological parameters in breast milk. METHOD: In a randomized controlled trial, 83 atopic women received either 4 g fish oil capsules (containing 3.7 g n-3 PUFA) (n = 40) or 4 g olive oil capsules (n = 43) from 20 weeks gestation until delivery. Breast milk was collected 3 days post-partum and fatty acids were analysed by gas liquid chromatography and IgA, sCD14 and cytokines (IL-5, IL-6, IL-10, TNF-alpha and IFN-gamma) were quantitated by ELISA or time resolved fluorescence (TRF). RESULTS: Omega-3 docosahexaenoic acid (DHA; 22:6n-3) and eicosapentaenoic acid (EPA; 20:5n-3) levels were significantly higher (P < 0.001) in breast milk from women supplemented with fish oil (n = 33, DHA mean 1.15%, SD 0.47% and EPA mean 0.16%, SD 0.07%) than in samples from the control group (n = 40, DHA mean 0.50%, SD 0.17% and EPA mean 0.05%, SD 0.02%). Breast milk arachidonic acid (AA; 20:4n-6) levels were significantly lower (P = 0.045) in the fish oil group (mean 0.55%, SD 0.12%) compared with the control group (mean 0.61%, SD 0.14%). Breast milk IgA was positively correlated with DHA (P = 0.046) and 22:5n-3 (P = 0.003), but inversely correlated with linoleic acid (LA; 18:2n-6) (P=0.034). Levels of sCD14 were also positively correlated with 22:5n-3 (P=0.009). Cytokines involved in IgA synthesis (IL-10 and IL-6) were also significantly correlated with both IgA and n-3 PUFA levels, although there were no differences in the levels of breast milk IgA, sCD14 or cytokines between study groups. CONCLUSION: Supplementation with fish oil during pregnancy significantly alters early post-partum breast milk fatty acid composition. omega-3 PUFA levels were positively associated with IgA and sCD14 levels, suggesting a relationship between fatty acid status and mucosal immune function.

Chi-Square Distribution↗
PubMed1999

Computerized breast measurement from conception to weaning: clinical implications.

The CBM system has enabled our laboratory to measure breast growth and demonstrate the importance of the short-term local control of milk synthesis in lactating women. Although the specific mechanism by which the short-term control of milk synthesis occurs has yet to be fully understood, it is now apparent that the interaction between storage capacity, degree of fullness, and frequency of milk removal plays a significant role. These factors demonstrate that the breastfeeding mother can take comfort in the individuality of her breast development and feeding pattern, which is uniquely adapted to suit the physiology of her breasts and the developmental requirements of her infant.

Breast↗
PubMed1999

Breast growth and the urinary excretion of lactose during human pregnancy and early lactation: endocrine relationships.

Breast volume and morphology of eight subjects were measured before conception and at intervals throughout pregnancy until 1 month of lactation. Breast volume before conception ranged from 293 to 964 ml. At the end of pregnancy the volume of breast tissue had increased by 145+/-19 ml (mean+/-S.E.M., n = 13 breasts, range 12-227 ml) with a further increase to 211+/-16 ml (n = 12 breasts, range 129-320 ml) by 1 month of lactation. Urinary excretion of lactose increased at 22 weeks of pregnancy, signalling the capacity of the breast to synthesize lactose at this time. During pregnancy, both the change in breast volume and the change in cross-sectional area of the areola were related to the concentration of human placental lactogen in the plasma. The growth of the nipple and the rate of excretion of lactose were related to the concentration of prolactin in the plasma. During the first 3 days after birth, the rate of excretion of lactose was related to the rate of excretion of progesterone. There was no relationship between the growth of the breast during pregnancy and the amount of milk produced at 1 month of lactation.

Adult↗
PubMed1999

Breast volume and milk production during extended lactation in women.

Quantitative measurements were made of relative breast volume and milk production from 1 month of lactation until 3 months after weaning, and the storage capacity of the breasts was calculated. The increase in breast tissue volume from before conception until 1 month of lactation was maintained for the first 6 months of lactation (means+/-S.E.M.) (190.3+/-13.1 ml, number of breasts, nb = 46). During this period of exclusive breast-feeding, 24 h milk production from each breast remained relatively constant (453.6+/-201 g, nb = 48), and storage capacity was 209.9+/-11.0 ml (nb = 46). After 6 months, breast volume, milk production and storage capacity all decreased. There was a relationship between 24 h milk production and the storage capacity of the breasts, and these both appeared to be responding to infant demand for milk. At 15 months of lactation, the 24 h milk production of each breast was substantial (208.0+/-56.7 g, nb = 6), even though the breasts had returned to preconception size. This was associated with an apparent increased efficiency of the breast (milk production per unit breast tissue) after 6 months, which may have been due to redistribution of tissues within the breast. The possible causes of the decrease in breast volume are discussed.

Adult↗
PubMed1998

A semiautomated enzymatic method for determination of nonesterified fatty acid concentration in milk and plasma.

An enzymatic assay for the determination of nonesterified fatty acid concentrations in milk and plasma is described. The procedure is semiautomated for use with a plate luminometer or plate spectrophotometer and enables routine batch processing of large numbers of small samples (< or =5 microL). Following the activation of nonesterified fatty acids (NEFA) by acylCoA synthetase, the current assay utilizes UDP-glucose pyrophosphorylase to link inorganic pyrophosphate to the production of NADH through the reactions catalyzed by phosphoglucomutase and glucose-6-phosphate 1-dehydrogenase. With this assay sequence the formation of NADH from NEFA is complete within 50 min at 37 degrees C. Enzymatic spectrophotometric techniques were unsuitable for NEFA determination in human milk due to the opacity of the sample. The use of the NADH-luciferase system has overcome this problem, allowing the enzymatic determination of NEFA in human milk. Sample collection and treatment procedures for milk and plasma have been developed to prevent enzymatic lipolysis and to limit interference from enzymes present in milk. The recovery of palmitic acid added to milk and plasma samples was 94.9+/-2.9 and 100+/-4.5%, respectively. There was no difference (P = 0.13) in plasma NEFA concentrations determined by the current method and a commercially available enzymatic spectrophotometric technique (Wako NEFA-C kit). Plasma NEFA concentrations determined by gas chromatography were 28% higher compared to both the Wako NEFA-C kit and the current method.

Animals↗
PubMed1998

Citrate, calcium, phosphate and magnesium in sows' milk at initiation of lactation.

Colostrum and milk were collected from ten sows at frequent intervals from before farrowing until 9 d after farrowing. Ionized calcium, pH, and total concentrations of citrate, calcium, phosphate and magnesium were measured in whole milk. The diffusible fraction of the mammary secretion was separated by ultrafiltration and was used for the measurement of diffusible citrate, calcium, phosphate and magnesium. The pH before farrowing was 5.7, and increased to 6.5 on day 4 as total calcium and phosphate also increased. Before farrowing, total and diffusible citrate were 7.8 and 7.3 mM respectively, while diffusible phosphate was 11.9 mM, and these concentrations all decreased during the study period. Total magnesium ranged between 3.3 and 4.1 mM, while diffusible magnesium ranged between 2.0 and 3.1 mM. While these concentrations and patterns of change of diffusible calcium and citrate are quite different from those of women's milk during the first week after birth, theoretical physicochemical relationships between diffusible calcium and citrate, and ionized calcium and HPO4(2-) were corroborated by these results. We conclude that diffusible citrate plays an important role in the determination of the concentration of diffusible calcium. However, while citrate may be the major determinant of the total concentration of calcium in women's milk, this is not the case in sows' milk.

Animals↗
PubMed1998

Exercise intensity and metabolic response in singles tennis.

The aim of this study was to determine exercise intensity and metabolic response during singles tennis play. Techniques for assessment of exercise intensity were studied on-court and in the laboratory. The on-court study required eight State-level tennis players to complete a competitive singles tennis match. During the laboratory study, a separate group of seven male subjects performed an intermittent and a continuous treadmill run. During tennis play, heart rate (HR) and relative exercise intensity (72 +/- 1.9% VO2max; estimated from measurement of heart rate) remained constant (83.4 +/- 0.9% HRmax; mean +/- s(x)) after the second change of end. The peak value for estimated play intensity (1.25 +/- 0.11 steps x s(-1); from video analysis) occurred after the fourth change of end (P< 0.005). Plasma lactate concentration, measured at rest and at the change of ends, increased 175% from 2.13 +/- 0.32 mmol x l(-1) at rest to a peak 5.86 +/- 1.33 mmol x l(-1) after the sixth change of end (P < 0.001). A linear regression model, which included significant terms for %HRmax (P< 0.001), estimated play intensity (P < 0.001) and subject (P < 0.00), as well as a %HRmax subject interaction (P < 0.05), accounted for 82% of the variation in plasma lactate concentration. During intermittent laboratory treadmill running, % VO2peak estimated from heart rate was 17% higher than the value derived from the measured VO2 (79.7 +/- 2.2% and 69.0 +/- 2.5% VO2peak respectively; P< 0.001). The %VO2peak was estimated with reasonable accuracy during continuous treadmill running (5% error). We conclude that changes in exercise intensity based on measurements of heart rate and a time-motion analysis of court movement patterns explain the variation in lactate concentration observed during singles tennis, and that measuring heart rate during play, in association with preliminary fitness tests to estimate VO2, will overestimate the aerobic response.

Adult↗
PubMed1998

Homeostatic mechanisms that regulate lactation during energetic stress.

Apart from the metabolic differences between species (ruminant vs. nonruminant), there are other important physiologic differences in both the energy requirements for lactation and in the control of milk production between dairy cows and women. Unlike dairy cows, the partitioning of nutrients for lactation in women therefore cannot be generalized to all lactating women but must be related to individual women, taking into account their particular metabolic circumstances. Homeorhetic models may be appropriate for women in developing countries, whereas in developed countries, the flexibility in both homeostatic and homeorhetic adaptations to the substrate demands for milk synthesis means that women can adopt a variety of strategies to support the metabolic demands of lactation. In these women, as in dairy cows, body reserves, dietary intake and milk production vary widely among individuals, and individual differences in capacity for homeorhetic regulation of nutrient partitioning under these conditions require further investigation.

Animals↗
PubMed1997

Bioluminescent methods for determining metabolites in micro-samples of pig plasma.

A highly sensitive and simplified method for the luminometric determination of plasma metabolites has been developed. Furthermore, the technique has been automated for the Dynatech ML2250 Microtiter Plate Luminometer and can be applied to the measurement of any plasma metabolite which may be coupled to a reaction involving the reduction of NAD+. Assays are described for lactose/galactose, beta-hydroxybutyrate and D-lactate, and have been validated with plasma samples. The assays require 1-2 microliters of plasma, and are capable of detecting concentrations below 5 mumol/l. Since luminometry is based on the kinetics of the luciferase/oxidoreductase enzyme system, components of complex biological samples may interfere with the rate of the reaction; necessitating the use of internal standards for individual samples. However, the need for internal standards to account for sample to sample variation in the luminescent response, has been eliminated with the present technique.

3-Hydroxybutyric Acid↗
PubMed1996

Changes in the concentration of fructose in the blood of piglets of different ages after doses of fructose, fructose plus glucose, and sucrose.

We investigated the hydrolysis of sucrose in the small intestine and the subsequent absorption and metabolism of fructose in sucking piglets by measuring temporal changes in the concentration of fructose in the plasma following the administration of physiological amounts of these carbohydrates. Calculations of the area under the curve for fructose in the plasma showed that there was no age limit to the piglets' ability to absorb fructose. However, there was a limit to the amount of fructose that the younger piglets could get from a dose of sucrose. Indeed, we demonstrated that there was a positive linear correlation between a piglet's capacity to hydrolyse sucrose and the age of the piglet up to 15 d of age (r 0.98). The half-life for fructose was 495, 103, 38, 49 and 28 min in 2-, 5-, 7-, 10- and 15-d-old piglets respectively and, thus, there was only limited utilization of fructose in the younger piglets. However, there were 13.0- and 1.4-fold increases in the elimination rate of fructose from the plasma of piglets from 2 to 7 d and from 7 to 15 d respectively, consistent with the reported increase in the deposition of fat in piglets of a similar age range. Hence, the effective metabolism of fructose may be partially dependent on the amount of adipose tissue present and the phosphorylation of this monosaccharide by hexokinase (EC 2.7.1.1) in this tissue.

Aging↗