Osteopenia Of Prematurity Research Articles

Multifaceted Dermal Ultrastructural Clues for Ehlers-Danlos Syndrome with Arterial Rupture and Type I Collagen R-to-C Substitution

Type I collagen arginine-to-cysteine (R-to-C) substitutions were found in three middle-aged adults suffering from spontaneous dissection of medium-size arteries. This disorder enters the heterogeneous spectrum of the Ehlers-Danlos syndrome (EDS). Despite similar genetic mutation and arterial alterations, two distinct clinical presentations were identified showing signs of either the EDS classic type or premature osteopenia alone. Ultrastructural changes were found in the dermal collagen fibrils, elastic fibers, and proteoglycan components. The cross-section of most collagen fibrils was rounded, but with diverse diameters. Flower-like outlines of collagen fibrils were rarely disclosed. Large hyaluronic acid globules pushed apart the collagen bundles in the case with EDS classic-type presentation. Elastic fibers contained unusual annular microcalcifications. In conclusion, ultrastructural changes were found in diverse connective-tissue components despite the fact that the mutations were found to be specific for the collagen molecules. In addition, two distinct clinical presentations were found and were correlated with peculiar ultrastructural alterations.

Osteopenia of Prematurity: The brittle challenge

Osteopenia of Prematurity: The brittle challenge

Quantitative ultrasound and biochemical parameters for the assessment of osteopenia in preterm infants

Objective. Our study aimed to evaluate the feasibility of quantitative ultrasound (QUS) evaluation in osteopenia of prematurity and to compare the results to biochemical parameters.Methods. QUS assessment of bone was performed at the end of the first postnatal week and at term-corrected age (CA) in premature infants (N = 30) and within the first week in full-term infants (N = 25). On the same day of measurement of QUS, the serum calcium, phosphorus (inorganic), and alkaline phosphatase (ALP) activity were measured in the preterm infants.Results. The median of tibia z score at term-CA in premature infants was significantly lower compared to that of first postnatal week (−1 and 0.4, respectively; p < 0.0001) and it was also lower than that of term-matched controls (0.0; p = 0.001). Preterm infants at term-CA had lower weights and lengths in comparison to term infants. The median ALP value was 585 IU/L at the first postnatal week and 703 IU/L at term-CA in preterm infants (p = 0.003). The median tibia z score of infants with ALP ≥900 IU/L was significantly lower than that of the infants with ALP <900 IU/L (−1.4 vs. 0.1; p = 0.001). An inverse correlation was found between ALP levels and tibia z score at term-CA in preterm infants (rho = −0.61, p = 0.01).Conclusions. Bone density of preterm infants at term-CA was lower than that at first postnatal week. Serum ALP levels increased during the first postnatal weeks. The tibia z scores were correlated to serum ALP levels. QUS is a good screening tool for the detection of osteopenia.

Longitudinal Measurements of Bone Status in Preterm Infants

Quantitative ultrasound measurement of the speed of sound (SOS) through bone has been investigated as a means of assessing bone status in preterm infants. Few studies report longitudinal measurements. To assess longitudinal changes in bone SOS in preterm infants. Sixty preterm infants with gestational ages of < 33 weeks and with birth weight appropriate for gestational age (AGA), and 48 healthy, term AGA infants were enrolled. SOS measurements of the tibia were made within the first week of life in the preterm infants, and within the first 72 hours of life in the term infants. During their hospital stay, weekly measurements of tibial SOS were made in 29 of the preterm infants, who were divided into three gestational age groups: Group 1: 24-26 weeks (n = 8), Group 2: 27-29 weeks (n = 9), and Group 3: 30-32 weeks (n = 12). The median SOS value for the 60 newborn preterm infants was significantly lower than that for the 48 newborn term infants (2,924 versus 3,036 m/sec, p < 0.001). At each time point, SOS values for each of the preterm infant gestational age groups were significantly lower than the term newborn infant SOS values. SOS values decreased significantly over time for the entire cohort of 29 preterm infants (p < 0.001), and for Groups 1 (p = 0.015) and 2 (p = 0.003). At several time points, there was a significant negative correlation between serum alkaline phosphatase levels and SOS values, and a significant positive correlation between serum phosphorus levels and SOS values. SOS measurements of the tibia decline during hospitalization in preterm infants, suggesting a progressive loss of bone strength. Longitudinal measurements of bone SOS in combination with serum alkaline phosphatase and serum phosphorus levels may identify infants at risk of developing osteopenia of prematurity.

52 Evaluation of Correlation Between the Quantitative Bone Ultrasound and Serum Alkaline Phosphatase, and Bone Specific Alkaline Phosphatase in Very Low Birth Weight Infants at Risk for Osteopenia of Prematurity.

Background: Osteopenia of prematurity (OOP) is a common problem in extremely low birth weight (ELBW) infants. Early detection of poor bone mineralization is essential to minimize continued bone loss, optimize mineral intake and adjust therapies to prevent fractures. Serum indices of total alkaline phosphatase (AP), bone specific alkaline phosphatase (BsAP), calcium (Ca) and phosphorus (P) are often used as clinical markers in the diagnosis of osteopenia in this population. These indices, however, do not provide a specific measure of bone status. Radiographic methods of bone mineral assessment involve high cumulative radiation doses and logistical complexities making their routine use impractical in this fragile population. Quantitative bone ultrasound (QUS) is done using portable equipment which measures the speed of sound (SOS) conducted through bone tissue and does not involve radiation exposure. In addition, QUS measurements reflect not only bone mineral content, but also bone strength and elasticity, giving a more complete evaluation of bone status.Primary Objective: To examine the correlation between QUS measurements and serum AP, BsAP, Ca and P in very low birth weight infants.Methods: Eligible infants included all infants in our NICU with birth weight ≤ 1250 Gms considered at-risk for OOP. Baseline and weekly serum Ca, P, AP and BsAP were monitored for the first 4 weeks of life. QUS measurements were performed at 1 month of age and reported as a standardized score (z-score) and SOS. A Pearson correlation matrix was used to examine the relationship between serum and QUS measurements.Results/Conclusions: Preliminary analysis on 11 infants reveals no relationship between the traditional serum indices of OOP and QUS (AP; r=0.08, BsAP; r=0.02, p ≤ 0.0001). Data collection is ongoing until a total of 50 infants are enrolled. Further data will help to evaluate the relationship between QUS and serum indices of OOP, and the potential utility of QUS in evaluating OOP in the NICU setting.Anticipated number of subjects available for analyses by time of presentation; 20.

Necrotizing enterocolitis increases the bone resorption in premature infants

Background Necrotizing enterocolitis is a common neonatal gastrointestinal disease that affects approximately 10% of premature infants less than 1500 g. The average mortality is 20–40% and survivors may present with diarrhea or malabsorption, intestinal strictures and fistulas, feeding abnormalities and failure to thrive. It is not clear whether the higher incidence of this gastrointestinal disease in premature infants contributes to the risk of osteopenia of prematurity. Aim To examine bone turnover state in premature infants who had a necrotizing enterocolitis attack during postnatal period. Study design and subjects We examine the bone turnover markers in infants with necrotizing enterocolitis and compare them with infants with sepsis. Forty-one premature infants participated in the study and were divided into three groups. In group I, there were 14 premature infants who developed necrotizing enterocolitis with negative blood culture during their hospitalization. In group II, there were 12 premature infants who developed sepsis during their hospitalization. Age-matched 15 premature infants who were given parenteral nutrition served as control group (group III). Blood samples and 6-h urine samples were obtained for bone turnover markers and calcium, phosphorous, creatinine and 25-hydroxy vitamin D between the day 20 and 25. Bone osteoblastic activity was assessed by measurement of serum osteocalcin. Bone resorption was assessed by measurement of serum levels of β-CrossLaps and urinary deoxypyridinoline. Results There were no significant differences in bone osteoblastic activity among the groups, but bone resorption markers were significantly higher in infants with necrotizing enterocolitis compared to other groups ( p < 0.016). Conclusion Necrotizing enterocolitis increases the bone resorption in premature infants. It may be related with reduced glucagon like peptide-2 levels, a new intestinal hormone that is primary secreted from distal small intestine.

Cross-Sectional Study of Bone Mineral Density in Adult Survivors of Solid Pediatric Cancers

To investigate the hypothesis that survivors of pediatric solid cancer have low bone mineral density, a cross-sectional study was done of subjects who had received treatment for pediatric solid tumors before 16 years of age and were less than 40 years old at follow-up. Excluded were subjects treated for acute lymphoblastic leukemia or those who had received cranial irradiation, total body radiation, or nonautologous bone marrow transplant. The study group consisted of 38 subjects, with the most common diagnoses being lymphoma (n = 17), sarcoma (n = 8), Wilms tumor (n = 5), and neuroblastoma (n = 4). Median age was 22 years (range 12-32). Time from diagnosis of underlying cancer averaged 12.6 years (range 5.5-20.3). Using criteria of osteopenia (Z-score < or = -1.0 and > -2.0) and osteoporosis (Z-score < or = -2.0) for any one or more areas including total body, lumbar spine, total hip, or femoral neck density, 13 of the 38 subjects (34%) had osteopenia or osteoporosis. A further six subjects (16%) had isolated upper extremity osteopenia or osteoporosis. Multivariate analysis showed a direct relationship between the number of chemotherapy drugs administered and the presence of osteopenia or osteoporosis in the lower extremities (P = 0.03). Young survivors of childhood solid tumors are at increased risk of developing premature osteopenia or osteoporosis, and screening evaluations and follow-up are warranted.

Quantitative ultrasound for the assessment of osteopenia in preterm infants.

To evaluate the potential role of quantitative ultrasound (QUS) investigation in assessing the osteopenia of prematurity. QUS parameters measured at the time of discharge were related to the anthropometric characteristics and age (postnatal and gestational) of 51 (34 female and 17 male) preterm infants fed fortified human milk. QUS evaluation was performed at the humerus (h) by measuring two parameters: ultrasound velocity (hSOS, in m/s) and bone transmission time (hBTT, in micros). A group of 43 term infants (29 female and 14 male) was also evaluated. In preterm infants, significant correlations were found for hSOS and hBTT vs gestational age (r=0.504, 0.477, P<0.0001), length (r=0.641, 0.594, P<0.0001) and weight (r=0.580, 0.562, P<0.0001) at birth, and length (r=0.341, 0.332, P<0.05) and weight (r=0.331, r=0.362, P<0.05) at QUS measurement. In preterm infants, both QUS parameters were negatively correlated with age (r=-0.536, P<0.0001, r=-0.443, P<0.001) and were significantly lower than in the term infants (hSOS: 1664+/-42 m/s vs 1734+/-28 m/s, P<0.0001; hBTT: 0.58+/-0.24 micros vs 1.06+/-0.15 micros, P<0.0001) even when adjusted for body length (P<0.05). In preterm infants, hSOS was also negatively correlated with postconceptional age (r=-0.322, P<0.05). This study suggests that bone mineral accrual is mainly determined by the development in utero, and that prematurity induces a halt in the bone development process in the early postnatal period. QUS parameters are correlated with the severity of prematurity and might therefore have clinical applications when bone maturation in early life needs to be determined.

Distal radius fracture in a premature infant with osteopenia caused by handling during intravenous cannulation

We present a case of an infant with osteopenia of prematurity who sustained a fractured radius whilst being gently held/handled during insertion of an intravenous cannula. Osteopenia of prematurity occurs when the bone mineral content is significantly decreased compared to that of an infant of comparable size or gestational age. It may occur in as many as half of all infants whose birth weight is less than 1000 g [1,2]. The clinical findings in preterm infants with osteopenia include a widened anterior fontanelle, craniotabes, bony expansion of the wrists, costochondral beading and rib fractures. The radiological features are generalised bone demineralisation, widening, cupping and fraying of the distal metaphyses [3]. Biochemical changes include persistently low serum inorganic phosphate and markedly elevated alkaline phosphates levels [3].

Impact of lung inflammation on bone metabolism in adolescents with cystic fibrosis

Deficits in bone mineral density resulting in premature osteopenia and osteoporosis have been documented in cystic fibrosis patients for over 20 years. A high incidence of fractures and kyphosis in the continually increasing adult patient population and in post-lung transplant patients has highlighted the problems associated with poor bone health.The aetiology of osteoporosis in CF is multifactorial but centres on an uncoupling in the normal balance between bone formation and resorption. Delayed puberty, malabsorption and reduced weight-bearing exercise can result in inadequate bone mineral accretion in childhood and adolescence. Corticosteroid use and pro-inflammatory cytokines associated with infective respiratory exacerbations can accelerate bone loss. Dual energy X-ray absorptiometry is the most commonly available technique to measure bone mineral density. All patients should be scanned at least every 2 years from adolescence. The treatment of established disease with bisphosphonates shows encouraging early results.

Effects of Human Milk Fortification on Morbidity Factors in Very Low Birth Weight Infants

The use of human milk as a sole source of nutrients for preterm infants has been the subject of debate in recent years. We studied the morbidity factors associated with hospitalization of very low birth weight (VLBW) infants fed human milk with and without fortification. One hundred VLBW infants were randomly assigned to two groups with stratification for gestation and weight. The control group (n=50; mean birth weight 1239+/-186 g and mean gestation 29.3+/-2.1 wks) was fed human milk only, and in the fortifier group (n=50; mean birth weight 1245+/-191 g and mean gestation 29.5+/-2.1 wks), human milk was enriched with a fortifier after the babies reached a volume of 140 mL/kg/day by the enteral route. Weight was measured twice weekly, biochemical indices of nutritional and bone status and serum electrolytes were obtained weekly, and clinical evidence for sepsis, necrotizing enterocolitis and feeding intolerance was assessed regularly until infants were discharged. Hospital stay was less than 45 days in the majority (94%) of the babies in the fortifier group, whereas the majority (66%) of the babies in the control group stayed for more than 45 days (P<0.01). Low serum phosphorus and raised alkaline phosphatase levels were seen more frequently in the control group without fortification (P<0.01), as well as hyponatremia (P<0.01), late metabolic acidosis of prematurity (P<0.01) and culture-proven sepsis (P<0.05). There was no significant difference in the occurrence of necrotizing enterocolitis between the two groups (P>0.05). Human milk fortification has beneficial effects on the growth of VLBW infants and decreases hospital stay and morbidity associated with prematurity and very low birth weight, with economic and psychological benefits for the parents.

Management of the extremely preterm infant: is the replacement of estradiol and progesterone beneficial?

This review presents data to suggest that postnatal estradiol and progesterone replacement therapy may be beneficial in preterm infants. During pregnancy, maternal plasma levels of estradiol and progesterone increase up to 100-fold compared to the nonpregnant status. The fetus is also exposed to these increasing hormone levels. After delivery, estradiol and progesterone levels drop by a factor of 100 within 1 day. Whereas this is a physiological condition for an infant born at term, preterm delivery means withdrawal from the placental supply of these hormones at an earlier developmental stage. Seventy years ago, the idea was raised that preterm infants may benefit from the replacement of estrogens. Studies in which estrogen was injected subcutaneously showed only a slightly better bodyweight gain compared to placebo-treated controls and therefore routine use was not established. The effective treatment of postmenopausal osteoporosis with hormone replacement therapy led to a pilot study of estradiol and progesterone therapy to prevent osteopenia of prematurity. The highest median bone mineral accretion rate was found in the replacement group when the supplementation with calcium and phosphorus was also sufficient. None of the previous studies dealing with estrogen replacement controlled for achieved plasma levels of estradiol in the infants. In our controlled randomised pilot study with 30 preterm infants (15 in each group), we aimed to maintain intra-uterine plasma levels of estradiol and progesterone. Preterm infants with replacement of estradiol and progesterone for 6 weeks postnatally showed trends to higher bone mineral accumulation. In addition, a trend towards a lower incidence of chronic lung disease was found. Neurodevelopmental follow-up showed normal psychomotor development in infants given estradiol and progesterone, whereas the untreated infants (controls) showed a trend towards delayed development. Recent research emphasises that estradiol and progesterone may be important for brain development. Thus, while there is data indicating that postnatal estradiol and progesterone replacement therapy may be beneficial in preterm infants, experience with this new therapy is limited and extensive research is needed to address the potential benefits and to rule out adverse effects.

Osteopenia Of Prematurity Prevention And Treatment

This paper examines Osteopenia of Prematurity (OOP) in a triplet child born at 24 3/7 weeks gestation. The infant required an extensive hospitalization in a Neonatal Intensive Care Unit (NICU) due to his prematurity. During his hospitalization, he was diagnosised with bronchopulmonary dysplasia, experienced multiple episodes of sepsis, and required long-term total parenteral and diuretic therapy. The differential diagnosis, pathophysiology, and prevention and treatment regarding insufficient bone mineralization in premature infants are discussed.

Nutrition for ill neonates.

1. Danna M. Premer, MD* 2. Michael K. Georgieff, MD* 1. 2. *Department of Pediatrics, Division of Neonatology, University of Minnesota, Minneapolis, MN. After completing this article, readers should be able to: 1. List the factors on which the nutritional needs of the neonate depend. 2. Describe the factors that illnesses alter, thereby changing nutrient requirements. 3. Describe the levels of amino acids that can be initiated without causing intolerance or toxicity in most ill infants. 4. Delineate the adverse effects of protein malnutrition following an acute or prolonged illness or insult. From early in this century, investigators have attempted to determine the optimal nutrient delivery for term infants to promote normal growth and development. In the past 25 years, nutritional investigators have concentrated on the needs of the ideal, healthy preterm infant to try to mimic intrauterine growth and body composition. Although great progress has been made in characterizing the needs of healthy preterm and term infants, the needs of ill, physiologically unstable infants largely have been neglected. The primary reasons for this lack of investigation are the assumption that the needs of ill infants are similar to those of healthy infants and the difficulty of studying metabolic needs in ill infants. The persistent efforts of several groups of investigators and the development of new techniques to study metabolism now have begun to delineate the specific nutritional needs of this particular patient population. Drawing on models generated in the adult surgical intensive care literature of the 1980s makes it possible to try to elucidate the effect of common illnesses and conditions (eg, acute pulmonary disease, bronchopulmonary dysplasia[BPD], congenital heart disease[CHD], sepsis, and surgery) on neonatal metabolism and, therefore, nutritional requirements. The assumption is that changes from the norm in metabolism require alterations in substrate delivery (ie, nutrition). As with adults, it is likely that each illness induces characteristic changes in metabolism. The task for the practitioner is to customize nutritional delivery to fit the specific infant’s …

Dietitian Intervention in Neonatal Intensive Care Reduces Errors and Improves Clinical Outcomes

Previously, our facility's pediatric dietitian worked on the acute pediatric units, but not in the NICU. After establishing rapport and expertise with pediatricians and achieving pediatric board certification, the dietitian received more frequent consults from pediatric residents rotating through the NICU. The dietitian then marketed her services to the director of neonatology, began rounding and charting on all neonates in the level III NICU twice per week, gave nutrition lectures to the NICU staff, and collaborated on NICU research. Prior to dietitian involvement, preterm infants on PN received low average intakes of 30-40 mg/kg of calcium and phosphorus, with an average calcium:phosphorus ratio of 1.1:1. Due to frequent monitoring and recommendations from the dietitian, preterm infants now receive 80 mg/kg of calcium and 60 mg/kg of phosphorus at a ratio of ⩾ 1.3:1, which promotes bone accretion closer to the intrauterine rate and reduces osteopenia of prematurity. Further, preterm infants previously received low average intakes of 1.3 mg/kg of magnesium from PN, but now receive ⩾ 3 mg/kg, which is known to improve growth. Previously, the NICU received an average of 2 contacts per week by the pharmacy due to PN errors. These errors have been eliminated due to dietitian review of all PN orders. Formerly, neonatal growth curves were sporadically plotted, but now weights and head circumferences are plotted twice per week for all neonates (excluding those on high frequency ventilation). During transition from PN to enteral feedings, nutrient intakes previously averaged 60 Kcal/kg and ⩽ 2 g protein/kg, resulting in weight plateaus and losses for 1-2 weeks until full enteral feeds were achieved. Due to dietitian involvement, over 90% of all neonates now receive ⩾ 90 Kcal/kg and ⩾ 3 g protein/kg during transition, with weight gains > 20-35 g/day. As an integral member of the NICU team, dietitian intervention greatly improved nutritional monitoring, intake, and growth of preterm infants, which is known to improve outcome and reduce hospital costs.

THE EFFECT OF LOW-DOSE ALUMINUM ON BONE TURNOVER IN PRETERM INFANTS

232 Aluminum(Al) as a contaminant of total parenteral nutrition(TPN) solutions infused into preterm infants at a rate of 15-30 ug(0.5-1 umol)/kg/d, is associated with accumulation in bone and interference with bone formation. The aim of our study is to use biochemical markers of bone formation(serum osteocalcin levels) and resorption (urinary N-telopeptide of type I collagen, or NTx) to determine whether lower Al levels in TPN solutions have an adverse effect on bone turnover. We studied two groups of preterm infants. The first group(n=22), mean gestational age of 29 weeks, range 25-35 10M, 12F, were studied first at 24-48h of life and then again at age 3 weeks, after having received TPN containing Ca gluconate, 200-400 mg (50-100mmol)/kg/d and potassium phosphate. 1 mmol/kg/d and sufficient Al contamination to provide 3-6 ug(0.1-0.2umol) per kg/d. Dextrose was tolerated up to a 25% solution and protein was gradually increased to 2.5g/dL. We measured serum osteocalcin by RIA and NTx/creatinine by ELISA and Al/creatinine by atomic absorption spectroscopy from a single spot urine sample. A second group of premature infants(n=6) all of 28 weeks gestation had a spot urine collected at 12 hours of life for NTx/creatinine. A Ca gluconate infusion of 200-400 mg(50-100mmol)/kg was begun at 12 hours of life; a urine sample was repeated at 36 hours of age. In the first group, at 3 wks, serum osteocalcin levels rose by 361%(p<0.05) while NTx/creatinine rose by 153% over the same time period(p<0.001). Urinary Al/creatinine at 3 weeks was 0.36±0.26 umol/mmol, similar to past reported Al/creatinine of 0.23±0.19(SD) umol/mmol with TPN solutions contaminated with a fivefold higher load (Sedman, Klein, Merritt et al, N Engl J Med 1985; 312:1337-43). The 28-week preterm infants in the second group experienced a rise in NTx/creatinine of 109% from 12-36 hours of life, despite the early infusion of Ca gluconate. This represents an increase to 70% of the rise in NTx by 3 weeks as seen in the first group. These data support the hypothesis that most of the infused Al was retained by the body but that the low dose of Al seen in our presently-constituted TPN solutions does not adversely affect bone formation. However, the amount of Ca infused in TPN solutions is insufficient to prevent a marked increase in bone resorption within the first 48 hours of life. Thus, osteopenia of prematurity may be due in part to the rapid rise in bone turnover post partum as there is insufficient time for full mineralization of bone.

Calcium Supplementation In Extremely Low Birth Weight (ELBW) Infants With Osteopenia Of Prematurity And Elevated Alkaline Phosphatase Levels: A Preliminary Report 597

Calcium Supplementation In Extremely Low Birth Weight (ELBW) Infants With Osteopenia Of Prematurity And Elevated Alkaline Phosphatase Levels: A Preliminary Report 597

Osteopenia of Prematurity

The objective of this review is to provide an overview of intermittent fasting regimens, summarize the evidence on the health benefits of intermittent fasting, and discuss physiological mechanisms by which intermittent fasting might lead to improved ...Read More

Journal of Bone and Mineral Research

Of 118 consecutive white patients referred for asymptomatic primary hyperparathyroidism, the diagnosis was clinically confirmed in 100, of whom 85 adults had a serum calcium less than 3.0 mM (12 mg/dl) and no skeletal, rheumatic, or significant neuropsychiatric symptoms, azotemia, or other significant illnesses. Among these 85, 68 had both asymptomatic and medically uncomplicated hyperparathyroidism, whereas 17 had historical, radiographic, or ultrasonic evidence of renal stone disease. The 20% with past or present renal calculi concentrated their urine significantly better than the 68 others (p = 0.05), but these two groups were otherwise not distinguished by the tests we performed, so all 85 patients were analyzed together. Systolic and diastolic blood pressures were normal, but premature osteopenia and/or impaired renal function were present in 29-36% of the patients. Micrometer measurements of metacarpal radiographs and 125I photon absorptiometry at the shaft of the radius revealed cortical osteopenia. Osteopenia was equally significant in the distal radius (cortical plus trabecular bone). These quantitative measurements were superior to routine bone radiography, and ROC analysis showed that 125I absorptiometry at either site was superior (p less than 0.01) to metacarpal cortex measurements for detecting premature osteopenia, which was present in more than a third of these patients. Creatinine clearances (24 h) and maximum urine concentrating capacity (overnight dehydration plus the synthetic vasopressin analog DDAVP) were each significantly reduced, despite all patients' normal BUN and serum creatinine levels. Sequential performance of a 24 h creatinine clearance and a urine concentration test revealed abnormalities in the renal function of 27 of 74 patients (36%), with a specificity of 95% and a higher sensitivity than either test alone (27-29%).(ABSTRACT TRUNCATED AT 250 WORDS)

Bone mineral accretion rate and calcium intake in preterm infants.

Thirty six preterm infants (20 boys) of 25 to 32 weeks' gestation were observed from birth to around 40 weeks' postconception. When oral feeding became possible, nine received mother's own breast milk (group B), 15 formula feed (group F), and 12 formula feed supplemented with calcium (5 ml 10% calcium gluconate/100 ml feed) and phosphorus (0.5 ml 17% potassium phosphate similarly) (group S). All received a daily supplement of 400 IU vitamin D. Intakes of calcium, phosphorus, vitamin D, energy, and fluid volume were recorded. When oral feeding started, and near 40 weeks' postconception, bone mineral content of the forearm was measured by photon absorptiometry; weight and crown-heel length were also measured. After logarithmic transformation of the measurements, there were no significant intergroup differences between the mean rate constants for weight or crown-heel length describing growth during the observation period. The mean rate constant for mineral accretion (M) was significantly higher in group S than in both the others. Pooling all data, M was significantly correlated with calcium intake but not with any other variable. Mineral supplementation of feed can reduce but not cure osteopenia of prematurity.