Influence of omega-3 polyunsaturated fatty acids from fish oil or meal on the structure of lipid microdomains in bovine luteal cells.

Biological membranes are composed of a lipid bilayer and proteins that form lipid microdomains. This study examined the effects of fish byproducts on lipid-protein interactions within lipid microdomains of bovine luteal cells. In Exp. 1 and 2, luteal cells were prepared from corpora lutea (CL; n = 4 to 8) collected at an abattoir. Exp. 1 was conducted to optimize ultrasonication in a detergent-free protocol for isolation of lipid microdomains. A power setting of 10 to 20% was effective in isolating lipid microdomains from bulk lipid. In Exp. 2, cells were cultured in control medium or fish oil to determine influence of fish oil on distribution of lipid microdomain markers and prostaglandin F2α (FP) receptors. Cells treated with fish oil had a smaller percentage of microdomain markers and FP receptor in microdomains (P < 0.05). In Exp. 3 and 4, cells were prepared from mid-cycle CL obtained from cows supplemented with corn gluten meal (n = 4) or fish meal (n = 4). Exp. 3 examined effects of dietary supplementation on distribution of lipid microdomain markers and FP receptor and Exp. 4 on fatty acid composition within lipid microdomains. A smaller percentage of lipid microdomain markers and FP receptor was detected in microdomains of cells collected from fish meal supplemented animals (P < 0.05). In Exp. 4, a greater percentage of omega-3 polyunsaturated fatty acids was detected in bulk lipid from fish meal supplemented cows (P < 0.05). Results show that fish byproducts influence lipid-protein interactions in lipid microdomains in bovine luteal cells.

Effect of fish meal supplementation on spatial distribution of lipid microdomains and on the lateral mobility of membrane-bound prostaglandin F2α receptors in bovine corpora lutea.

This study examined the effects of fish meal supplementation on spatial distribution of lipid microdomains and lateral mobility of prostaglandin F2α (FP) receptors on cell plasma membranes of the bovine corpus luteum (CL). Beef cows were stratified by BW and randomly assigned to receive a corn gluten meal supplement (n = 4) or fish meal supplement (n = 4) for 60 d to allow incorporation of fish meal-derived omega-3 fatty acids into luteal tissue. Ovaries bearing the CL were surgically removed between days 10 to 12 after estrus corresponding to approximately day 60 of supplementation. A 200-mg sample of luteal tissue was analyzed for fatty acid content using gas-liquid chromatography (GLC). The remaining tissue was enzymatically digested with collagenase to dissociate individual cells from the tissue. Cells were cultured to determine the effects of dietary supplementation on lipid microdomains and lateral mobility of FP receptors. Luteal tissue collected from fish meal-supplemented cows had increased omega-3 fatty acids content (P < 0.05). Lipid microdomain total fluorescent intensity was decreased in dissociated luteal cells from fish meal-supplemented cows (P < 0.05). Micro and macro diffusion coefficients of FP receptors were greater for cells obtained from fish meal-supplemented cows (P < 0.05). In addition, compartment diameter of domains was larger, whereas resident time was shorter for receptors from cells obtained from fish meal-supplemented cows (P < 0.05). Data indicate that dietary supplementation with fish meal increases omega-3 fatty acid content in luteal tissue causing disruption of lipid microdomains. This disruption leads to increased lateral mobility of the FP receptor, increased compartment sizes, and decreased resident time, which may influence prostaglandin signaling in the bovine CL.

Fish meal supplementation increases bovine plasma and luteal tissue omega-3 fatty acid composition.

The objective of this experiment was to determine if dietary inclusion of fish meal would increase plasma and luteal tissue concentrations of eicosapentaenoic and docosahexaenoic acids. Seventeen nonlactating Angus cows (2 to 8 yr of age) were housed in individual pens and fed a corn silage-based diet for approximately 60 d. Diets were supplemented with fish meal at 5% DMI (a rich source of eicosapentaenoic acid and docosahexaenoic acid; n = 9 cows) or corn gluten meal at 6% DMI (n = 8 cows). Body weights and jugular blood samples were collected immediately before the initiation of supplementation and every 7 d thereafter for 56 d to monitor plasma n-3 fatty acid composition and BW. Estrous cycles were synchronized using 2 injections of PGF(2α) administered at 14-d intervals. The ovary bearing the corpus luteum was surgically removed at midcycle (between d 10 and 12) after estrus synchronization, which corresponded to approximately d 60 of supplementation. The ovary was transported to the laboratory, and approximately 1.5 g of luteal tissue was stored at -80°C until analyzed for n-3 fatty acid content. Initial and ending BW did not differ (P > 0.10) between cows supplemented with fish meal and those with corn gluten meal. Plasma eicosapentaenoic acid was greater (P < 0.05) beginning at d 7 of supplementation and docosahexaenoic was greater (P < 0.05) beginning at d 14 of supplementation for cows receiving fish meal. Luteal tissue collected from fish meal-supplemented cows had greater (P < 0.05) luteal n-3 fatty acids and reduced (P < 0.05) arachidonic acid and n-6 to n-3 ratio as compared with tissue obtained from cows supplemented with corn gluten meal. Our data show that fish meal supplementation increases luteal n-3 fatty acid content and reduces available arachidonic acid content, the precursor for PGF(2α). The increase in luteal n-3 fatty acids may reduce PGF(2α) intraluteal synthesis after breeding resulting in increased fertility in cattle.

Lymphatic malformations: a proposed management algorithm.

OBJECTIVE: The aim of this study was to develop a management algorithm for cervicofacial lymphatic malformations, based on the authors' experience in managing these lesions as well as current literature on the subject. STUDY DESIGN AND METHODS: A retrospective medical record review of all the patients treated for lymphatic malformations at our institution during a 10-year period (1998-2008) was performed. DATA COLLECTED: age at diagnosis, location and type of lesion, radiologic investigation performed, presenting symptoms, treatment modality used, complications and results achieved. RESULTS: 14 patients were identified. Eight (57%) male and six (43%) female. There was an equal distribution between the left and right sides. The majority (71%) of cases were diagnosed within the first year of life. The majority of lesions were located in the suprahyoid region. The predominant reason for referral was an asymptomatic mass in 7 cases (50%) followed by airway compromise (36%) and dysphagia (14%). Management options employed included: observation, OK-432 injection, surgical excision and laser therapy. In 5 cases (36%) a combination of these were used. CONCLUSION: Historically surgical excision has been the management option of choice for lymphatic malformations. However due to the morbidity and high complication rate associated this is increasingly being questioned. Recent advances in sclerotherapy e.g. OK-432 injection have also shown significant promise. Based on experience in managing these lesions as well as current literature the authors of this paper have developed an algorithm for the management of cervicofacial lymphatic malformations.

Hypothermic responses to infection are inhibited by alpha2-adrenoceptor agonists with possible clinical implications.

BACKGROUND: alpha(2)-Adrenoceptor agonists are currently used as primary sedative agents in high dependency patients who are at high risk of sepsis. Clinical surveillance of such patients relies in part on their ability to mount appropriate responses to infection, in particular thermal responses. Thermoregulatory responses to infection are well studied in the rat and in this species, and humans, infection can induce febrile, hypothermic, or mixed hypothermic and febrile responses. The involvement of noradrenergic systems in thermal responses to infection prompted the hypothesis that ligands that act on adrenoceptors may interfere with the normal thermal responses to infection. METHODS: In this study on rats, the effect of infusion of the selective alpha(2)-agonist, mivazerol, on hypothermic and plasma corticosterone responses induced by bacterial lipopolysaccharide (LPS) was investigated. RESULTS: Clinically effective doses of mivazerol (4.8 and 10 microg kg(-1) h(-1)) had no effect on body temperature alone. However, mivazerol significantly inhibited the typical thermoregulatory response to bacterial LPS in a dose-dependent manner. This effect was mimicked by the selective alpha(2)-agonist, UK14304-18 (6 microg kg(-1) h(-1)), and antagonized by the alpha(2)-antagonist, RX811059A (7 microg kg(-1) h(-1)). The alpha(2)-ligands had no effect on basal or LPS-induced corticosterone levels. CONCLUSIONS: These data suggest that early thermoregulatory responses to infection can be selectively antagonized by ligands that activate alpha(2)-adrenoreceptors. High dependency patients receiving alpha(2)-adrenoceptor agonists may not be capable of mounting a normal thermal response to infecting organisms and clinical monitoring using core temperature to detect infection may therefore be unreliable in these vulnerable patients.

Effect of copper status, supplementation, and source on pituitary responsiveness to exogenous gonadotropin-releasing hormone in ovariectomized beef cows.

The effect of Cu status, supplementation, and source on pituitary responsiveness to exogenous GnRH was evaluated using nine multiparous, nonpregnant, nonsuckling, ovariectomized Angus cows (7.1 +/- 3.3 yr; 622.9 +/- 49.8 kg; BCS = 6.0 +/- 0.5). Cows were considered Cu-deficient based on liver Cu concentrations (< 30 mg of Cu/kg of DM) after receiving a low-Cu, forage-based diet supplemented (DM basis) with 5 mg of Mo/kg and 0.3% S for 216 d. Copper-deficient cows were stratified based on age, BW, BCS, and liver Cu concentration and assigned randomly to repletion-phase treatments. Treatments included 1) control (no supplemental Cu); 2) organic (ORG; 100% organic Cu); and 3) inorganic (ING; 100% inorganic CuSO4). Treatments were formulated to meet all NRC recommendations, except for Cu, which was supplemented to ORG and ING cows at 10 mg of Cu/kg of dietary DM. During the 159-d repletion phase, Cu status was monitored via liver biopsy samples, and all cows received exogenous progesterone. A controlled intravaginal drug-release device (replaced every 14 d) was used to maintain luteal phase progesterone as a means to provide negative feedback on the hypothalamic-pituitary axis. During the repletion phase, liver Cu concentrations did not differ between ORG and ING cows at any time. By d 77 of the repletion phase, all supplemented cows were considered adequate in Cu, and liver Cu concentrations were greater in supplemented than in nonsupplemented control cows on d 77 (P < 0.05) and throughout (P < 0.01) the repletion phase. Beginning on d 99, exogenous GnRH was administered to all cows at low (0, 3, and 9 microg; Exp. 1) and high doses (0, 27, and 81 microg; Exp. 2) at six different times. Cows were catheterized every fifth day, and blood samples were collected every 15 min for 1 h before and 4 h after GnRH administration and analyzed for LH concentration. In Exp. 1, Cu status and supplementation did not affect basal or peak LH concentrations, but total LH released tended (P < 0.07) to be greater in Cu-supplemented vs. control cows when 3 microg of GnRH was administered. In Exp. 2, there was no effect of Cu supplementation or source on basal, peak, or total LH released, regardless of GnRH dose. Pituitary LH concentrations did not differ across treatments. In conclusion, Cu status, supplementation, and source did not affect GnRH-induced LH secretion or pituitary LH stores in ovariectomized, progesterone-supplemented cows in this experiment.

Effect of copper, zinc, and manganese supplementation and source on reproduction, mineral status, and performance in grazing beef cattle over a two-year period.

Crossbred, multiparous beef cows (n = 178 in Year 1; n = 148 in Year 2) were used to evaluate the effects of Cu, Zn, and Mn supplementation and source on reproduction, mineral status, and performance in grazing cattle in eastern Colorado over a 2-yr period. Cows were stratified by expected calving date, age, BW, BCS, and liver mineral status and assigned to the following treatments: 1) control (no supplemental Cu, Zn, or Mn); 2) organic (ORG; 50% organic and 50% inorganic Cu, Zn, and Mn); and 3) inorganic (ING; 100% inorganic CuSO4, ZnSO4, and MnSO4). Free-choice mineral feeders were used to provide current NRC-recommended concentrations of Cu, Zn, and Mn from 82 d (Year 1) and 81 d (Year 2) before the average calving date of the herd through 110 d (Year 1) and 135 d (Year 2) after calving. At the end of Year 1, supplemented cows had greater liver Cu (P < 0.01), Zn (P < 0.05), and Mn (P < 0.01) concentrations compared with controls, whereas liver Cu concentration was greater (P < 0.01) in ORG vs. ING cows. At the end of Year 2, supplemented cows had greater (P < 0.01) liver Cu concentrations relative to controls, whereas control cows had greater (P < 0.02) liver Mn concentration than did supplemented cows. In Year 1, pregnancy rate to AI in control cows did not differ (P = 0.47) from supplemented cows, but there was a trend (P < 0.08) for pregnancy rate to be higher for ORG than ING cows. In Year 2, supplemented cows had a higher (P < 0.02) pregnancy rate to AI than controls. In both years, when cows were inseminated after an observed estrus, supplemented cows had a higher (P < 0.04) pregnancy rate than did controls. Also, for both years, overall 60-d pregnancy rate tended (P = 0.10) to be higher for supplemented cows than for controls. In Year 1, kilograms of calf weaned per cow exposed was greater (P < 0.02) in controls than in supplemented cows, and kilograms of calf weaned per cow exposed was greater (P < 0.01) in ING than ORG treatments. However, in Year 2, kilograms of calf weaned per cow exposed was greater (P < 0.02) in controls than in supplemented cows, and tended (P = 0.09) to be greater in ORG than ING treatments. Results indicate that supplementation and source of trace minerals affected mineral status and kilograms of calf weaned per cow exposed in grazing beef cows. Supplementation also improved pregnancy rate to AI compared with cows not supplemented with Cu, Zn, or Mn for more than 1 yr. Furthermore, mineral source may influence pregnancy rate to AI.

Effect of fish meal supplementation on plasma and endometrial fatty acid composition in nonlactating beef cows.

Seven nonlactating mature Angus cows (4 to 10 yr old) were used to examine the effects of fish meal supplementation on plasma and endometrial fatty acid composition. Cows were fed a corn silage-based diet supplemented with either fish meal, a rich source of the n-3 fatty acids, eicosapentaenoate and docosahexaenoate (n = 3; 5.1% of dietary DM), or corn gluten meal (n = 4; 8.5% of dietary DM) for approximately 64 d. Cows were given 25 mg of PGF2alpha (i.m.) on d 11 and 25 of supplementation to synchronize estrous cycles. On d 18 postestrus of the second estrous cycle, cows were slaughtered, and caruncular endometrium was dissected from uteri immediately after slaughter. Jugular blood samples were collected immediately before supplementation was initiated (d 0) and at 7-d intervals for 35 d of the study. Plasma eicosapentaenoic and docosahexaenoic acids did not differ between treatment groups on d 0 (P > 0.10); however, these fatty acids were greater in cows supplemented with fish meal over the first 35 d of supplementation compared with cows supplemented with corn gluten meal (P < 0.05). Endometrial docosahexaenoic acid did not differ (P = 0.12), whereas eicosapentaenoic acid was greater (P < 0.05) in cows supplemented with fish meal than in cows supplemented with corn gluten meal. These results indicate that dietary fish meal alters plasma and endometrial n-3 fatty acid composition in beef cows.

Leptin reduces food intake but does not alter weight regain following food deprivation in the rat.

OBJECTIVE: When animals are allowed free access to food following an extended period of food restriction, body weight is steadily restored to the pre-food restriction level, ie to a specific body weight 'set-point'. We tested the proposition that leptin is used as a signal by the brain to regulate body weight 'set-point'. To this end, we determined whether long-term leptin infusion in rats would prevent the normal weight regain after food restriction. METHODS: Male Sprague-Dawley rats received leptin (leptin-treated) or saline (vehicle-treated) by intravenous infusion. After a 2 week run-in period, food intake was adjusted to 50% of each individual's normal intake for 12 days. Two days prior to the return of unlimited access to food, one group of animals received continuous leptin infusion at 3 micro g/h for the next 14 days. Blood samples taken from the tail vein were used to determine leptin concentrations. A third group of animals that did not undergo food restriction but received saline infusion served as control. As leptin acts in the brain to modulate neuropeptide Y (NPY) levels, hypothalamic NPY content was measured at the end of the study. RESULTS: Food restriction to 50% normal intake for 12 days induced a 20% weight loss and significant reductions in plasma leptin compared with non-restricted control rats (0.5+/-0.1 vs 2.6+/-0.4 ng/ml, P<0.05). Intravenous infusion of leptin increased leptin concentrations four-fold compared with vehicle-treated animals (9.5+/-1.3 vs 2.2+/-0.4 ng/ml, P<0.05). The infusion of leptin attenuated the increase in daily food intake after free access to food was resumed (P<0.05 at 4, 6 and 8 days). Despite this, both groups of previously restricted rats had regained the same amount of weight after 12 days of ad libitum feeding. No difference was noted in NPY levels measured in the arcuate nucleus and the paraventricular nucleus, in line with the similar amounts of food eaten by all rats at the end of the experiment. CONCLUSION: Increasing plasma leptin concentrations just prior to the end of a period of food restriction reduced subsequent food intake, but did not appear to exert a major influence on the body weight 'set-point', as leptin did not prevent weight regain. The results of the present study suggest that leptin may be of little value in maintaining weight loss in individuals who have lost weight through dieting. Further research is required to understand the role of leptin in the regulation of energy balance.

Prophylaxis of radiation-associated mucositis in conventionally treated patients with head and neck cancer: a double-blind, phase III, randomized, controlled trial evaluating the clinical efficacy of an antimicrobial lozenge using a validated mucositis scoring system.

PURPOSE: Mucositis occurs in almost all patients treated with radiotherapy for head and neck cancer. The aim of this multicenter, double-blind, prospective, randomized trial was to evaluate the clinical efficacy of an economically viable antimicrobial lozenge (bacitracin, clotrimazole, and gentamicin [BcoG]) in the alleviation of radiation-induced mucositis in patients with head and neck cancer. PATIENTS AND METHODS: One hundred thirty-seven eligible patients were randomized to treatment with either antimicrobial lozenge (69 patients) or placebo lozenge (68 patients). The primary end point of the study was the time to development of severe mucositis from the start of radiotherapy. Secondary end points included severity and duration of mucositis, pain measurement, radiation therapy interruption, and quality of life. Mucositis was scored using a validated mucositis scoring system. RESULTS: Toxicity profiles were similar between the two arms of the study. The median time to development of severe mucositis from the start of radiotherapy was 3.61 weeks on BCoG and 3.96 weeks on placebo (P =.61). There were no statistically significant differences between the arms in the extent of severe mucositis as measured by physician, in oral toxicities as recorded by patients, or in radiotherapy delays. CONCLUSION: This study was conducted on the basis of a pilot study that demonstrated the BCoG lozenge to be tolerable and microbiologically efficacious. A validated mucositis scoring system was used. However, in this group of patients treated with conventional radiotherapy, the lozenge did not impact significantly on the severity of mucositis. Whether such a lozenge would be beneficial in treatment situations where rate of severe mucositis is higher (ie, in patients treated with unconventional fractionation or with concomitant chemotherapy) is unknown.

Interaction of circulating hormones with the brain: the roles of the subfornical organ and the organum vasculosum of the lamina terminalis.

1. Most circulating peptide hormones are excluded from much of the brain by the blood-brain barrier. However, they do have access to the circumventricular organs (CVO), which lack the blood-brain barrier. Three of the CVO, the subfornical organ (SFO), organum vasculosum of the lamina terminalis (OVLT) and area postrema, contain neurons responsive to peptides such as angiotensin II (AngII), atrial natriuretic peptide and relaxin. 2. We have studied the patterns of neuronal activation, as shown by Fos expression, in the SFO and OVLT in response to systemically infused AngII, relaxin or hypertonic saline and have found subgroups of neurons activated by the different stimuli. 3. Systemic infusion of relaxin or hypertonic saline activated neurons almost exclusively in the outer regions of the SFO and in the dorsal cap of the OVLT. Many of these neurons send axonal projections to regions of the brain subserving vasopressin secretion and thirst, such as the median preoptic, supraoptic and hypothalamic paraventricular nuclei. 4. At moderate blood concentrations, AngII only stimulates neurons in the inner core of the SFO and lateral regions of the OVLT. Higher levels of AngII in the bloodstream activate additional neurons in the outer parts of the SFO that connect to the supraoptic, paraventricular and median preoptic nuclei and these probably mediate water drinking and vasopressin secretion induced by blood-borne AngII. The efferent connections and the functions mediated by angiotensin-sensitive neurons in the inner core of the SFO and lateral part of the OVLT are unknown.

Effects of long-term maternal intravenous magnesium sulfate therapy on neonatal calcium metabolism and bone mineral content.

A prospective study was designed to determine whether calcium homeostasis and bone mineral content were affected adversely in preterm infants born to mothers receiving long-term antenatal therapy with magnesium sulfate. Preterm infants born to mothers receiving long-term antenatal therapy with magnesium sulfate and requiring prolonged bed rest for preterm labor were compared with infants of mothers not receiving magnesium sulfate but in whom prolonged bed rest was also required. Serum magnesium, calcium, phosphorus, osteocalcin, and parathyroid hormone were measured in infants at 0, 24, 48, and 72 h after delivery. Bone mineral content of the distal radius was measured 1 week postnatally and at term-equivalent postmenstrual age. Maternal serum mineral status indices obtained near delivery and bone indices were compared with those of their infants. The clinical characteristics and morbidities of the infants were similar between groups. We observed significantly greater serum concentrations of magnesium, phosphorus, and osteocalcin during the 72 h after delivery and a lower serum calcium concentration which normalized by 72 h in preterm infants whose mothers were treated with magnesium sulfate compared with infants whose mothers did not receive magnesium sulfate. Both groups, however, had similar radius bone mineral content measurements and anthropometric indices after delivery. These data suggest that although preterm infants born to mothers treated with magnesium sulfate have delayed clearance of magnesium and phosphorus, they have a normalization of serum calcium by 72 h after delivery and no significant differences in bone mineral content after delivery compared with infants whose mothers do not receive magnesium sulfate.

A comparison of effectiveness of biofeedback and pelvic muscle exercise treatment of stress incontinence in older community-dwelling women.

BACKGROUND: Research using biofeedback as a treatment for sphincteric incontinence began with Kegel's early studies using a perineometer and pelvic muscle exercises demonstrating a 90% improvement in urine loss symptoms. More recent studies using varying combinations of biofeedback and pelvic muscle exercises found symptom reduction rates of 78% to 90%, but these studies lacked the rigor of a "phase three," or randomized controlled clinical trial. METHODS: A randomized controlled trial assessed the efficacy of biofeedback for older women for treatment of sphincteric incompetence. One hundred thirty-five community-dwelling women were randomized in a single-blind trial to three groups: biofeedback, pelvic muscle exercise, or control. Incontinent episodes were monitored over 8 weeks of treatment and at 3 and 6 months thereafter. RESULTS: The number of incontinent episodes decreased significantly in the biofeedback and pelvic muscle exercise subjects but not in the control subjects for all severity of incontinence frequency subgroups. Improvement was maintained within the moderate and severe symptom subgroups for both treatments for at least 6 months but declined in subjects with mild incontinence frequency. Pelvic muscle activity (EMG) was significantly correlated with decreases in incontinent episodes, and only the biofeedback subjects showed significant improvement in EMGs. CONCLUSIONS: Biofeedback and pelvic muscle exercises are efficacious for sphincteric incompetence in older women. Benefits are maintained and improvement continues for at least 6 months postintervention. These therapies may be useful before considering invasive treatment.

Effect of parenteral calcium and phosphorus therapy on mineral retention and bone mineral content in very low birth weight infants.

HYPOTHESIS: If calcium and phosphorus are administered to very low birth weight infants in amounts larger than those currently used in standard parenteral nutrition solutions, apparent retention of calcium and phosphorus (intake minus urinary excretion) will increase and bone mineralization will improve. DESIGN: Randomized, controlled, double-blind trial. SETTING: Neonatal intensive care unit. PATIENTS: Twenty-four very low birth weight infants (< 1.2 kg) expected to receive parenteral nutrition exclusively for approximately 3 weeks beginning 3 days after birth. INTERVENTIONS: Infants received parenteral nutrition solutions, either the standard mixture containing 1.25 mmol calcium and 1.5 mmol phosphorus per deciliter (group STAND: n = 12, birth weight 921 +/- 171 gm, gestational age 27 +/- 2 weeks (mean +/- SD)) or 1.7 mmol calcium and 2.0 mmol phosphorus per deciliter (group HIGH: n = 12, 857 +/- 180 gm, 27 +/- 2 weeks). MAIN OUTCOME MEASURES: Intake, urinary excretion, and apparent retention of calcium, phosphorus, and magnesium every 3 days during parenteral nutrition therapy. Serum indexes of mineral status twice during therapy. Bone mineral content of the distal segment of the left radius at 1, 4, 8, and 26 weeks. RESULTS: Apparent calcium retention (1.2 +/- 0.2 vs 1.6 +/- 0.2 mmol.kg-1.d-1) and phosphorus retention (1.4 +/- 0.2 vs 1.8 +/- 0.4 mmol.kg-1.d-1) differed significantly (p < 0.01) between groups STAND and HIGH, respectively; neither changed with the duration of parenteral nutrition therapy. Serum calcium, magnesium, parathyroid hormone, 25-hydroxyvitamin D, and osteocalcin concentrations were similar in both groups. Serum phosphorus concentration was significantly higher in group HIGH than in group STAND (p = 0.025). The absolute bone mineral content and the rate of increase in bone mineral content between 1 and 4, 1 and 8, and 1 and 26 weeks were significantly greater in group HIGH than in group STAND. CONCLUSIONS: Increased parenteral intakes of calcium and phosphorus resulted in greater retention of these minerals during parenteral nutrition therapy and in greater bone mineral content after therapy.

Calcium homeostasis in pregnant women receiving long-term magnesium sulfate therapy for preterm labor.

OBJECTIVES: The hypothesis of this study is that calcium homeostasis and bone mineralization are altered in pregnant women receiving long-term therapy with magnesium sulfate as compared with similar women not receiving magnesium sulfate to control preterm labor. STUDY DESIGN: Thirty-nine women between 24 and 32 weeks' gestation, matched for age, race, and duration of bed rest, were enrolled. Indices of calcium homeostasis in serum and urine were measured serially, and bone mineralization of the distal radius was measured at 1 and 11 weeks post partum. RESULTS: Magnesium therapy was administered for a mean duration of 26 +/- 14 days and a cumulative dose of 1405 +/- 963 gm. Serum concentrations of magnesium, phosphorus, and parathyroid hormone increased and those of calcium decreased from baseline values in the magnesium sulfate group and remained uniform throughout the 3-week investigation. The serum magnesium, phosphorus, parathyroid hormone, and calcium concentrations in the control group were unchanged during the study and differed significantly from those in the magnesium sulfate group (p < 0.001). Urinary output of magnesium, calcium, and copper was significantly greater in the magnesium sulfate group than in the control group throughout the study. Urinary losses of calcium in the magnesium sulfate group, approximately 800 to 900 mg/day, were substantial. Although radius bone density 1 week post partum did not differ between groups, the change in bone density from 1 to 11 weeks post partum was significantly lower in the magnesium sulfate group than in controls. CONCLUSIONS: These data suggest that calcium homeostasis is altered during and after long-term magnesium sulfate therapy. The marked, prolonged urinary calcium losses may affect maternal bone mineralization.

Bone mineralization outcomes in human milk-fed preterm infants.

We evaluated bone mineralization by single photon absorptiometry at 2 y in a cohort of preterm infants studied since birth. Infants were fed human milk fortified with Ca [to achieve 80 mg/dL (19.96 mmol/L)] and P [40 mg/dL (12.91 mmol/L)] from wk 2 through 8 after birth. After hospital discharge, infants were divided into two groups (HM and F) determined by the timing of the introduction of cow milk-based formula. Mid-radius bone mineral content (BMC) was assessed in 10 infants who were breast-fed (HM) for a minimum of 2 mo after hospital discharge and 11 who were bottle-fed (F). The mean duration of human milk-feeding differed by design between HM and F groups (31 +/- 15 versus 11 +/- 3 wk, respectively). Although we had observed previously that group F had significantly greater BMC values at 16, 25, and 52 wk compared with values in group HM, we found similarities in BMC values (180 +/- 30 mg/cm) between groups at 2 y. The 2-y cohort comprised healthy infants and the groups had similar birth weights, lengths of gestation, and values for weight (10.8 +/- 1.1 kg), length (82 +/- 2 cm), and bone width (7.8 +/- 1.1 mm). Follow-up outcomes at 2 y in preterm infants fed fortified human milk in hospital suggest that if they continue to receive human milk after hospital discharge, radius BMC will "catch-up" to that of similar infants given formula in the posthospitalization period.