Mineral balance and whole body bone mineral content in very low-birth-weight infants

Fat and mineral metabolic balance studies were performed in 25 normal very low-birth-weight infants ( 1500 g at birth) fed either pooled pasteurized human milk supplemented with calcium, phosphorus and magnesium, or a preterm formula. Calcium, phosphorus and magnesium intake were similar in both groups and averaged 100mg/kg/day, 72 mg/kg/day and 8 mg/kg/day, respectively. Calcium and phosphorus retention was higher in the subjects fed fortified human milk than in those receiving a preterm formula (65±14 and 62±9mg/kg/day versus 55±12 and 47±7mg/kg/day respectively). The difference was only significant for phosphorus. Magnesium retention was similar in the two groups and averaged 3 mg/kg/day. Fat intake and absorption was significantly higher in the preterm formula fed group than in the one fed fortified human milk (5.5±0.4 g/kg/day and 88±4% versus 4.2±1 g/kg/day, 79±6% respectively). Assessment of the whole body bone mineral content by dual energy X-ray absorptiometry was performed at 3 and 6 months of age in another group of 25 low-birth-weight infants fed either fortified human milk or a preterm formula. Whole body bone mineral content (BMCt) was low (43.3±30.8 g of hydroxyapatite) at 3 months of age (theoretical term) compared to normal full-term newborns at birth. There was no significant influence of the diet. At 6 months of age, BMCt reached 168.6±36.6g, a value similar to that of full-term newborns, with no significant difference between the two regimen groups. The deficit in the 12 subjects who had a BMCt under 30 g at 3 months of age had been corrected at age 6 months. Premature babies fed a pooled pasteurized human milk enriched with calcium, phosphorus and magnesium favored a better retention of calcium and phosphorus. However, no significant influence of the two diets studied was observed on the gain in BMCt over the first 6 months of life.     

High frequency oscillation in newborn infants with respiratory failure

Objective: To report ventilation strategies, survival and complications in 39 outborn infants treated with high frequency oscillatory ventilation (HFOV).
Methodology Data were collected prospectively between 1 May 1992 and 31 December 1993 on all infants treated with HFOV who had severe respiratory failure despite optimal conventional ventilation.
Results Twenty-eight out of 39 (72%) survived. Of the 15 infants with birthweights <1500g, eight survived. Best survival rates were for infants with pulmonary interstitial emphysema with air leak (4/5) and for infants of birthweight >1500g with hyaline membrane disease (8/8), and meconium aspiration syndrome (7/7). Three infants deteriorated while on HFOV and required extracorporeal membrane oxygenation. Complications were: (i) development of pulmonary interstitial emphysema (1); (ii) recurrence of pneumothorax (3); (iii) hypotension (2); and (iv) bronchopulmonary dysplasia (9). One of the eight infants weighing <1500g who received HFOV in the first week of life developed periventricular haemorrhage.
Conclusion The initial results of HFOV for severe respiratory failure were encouraging although a learning curve was encountered with its introduction.     

105Changes in Nitric Oxide Levels After Deep Dermal injury in the Female,Red Duroc Pig (FRDP)

Introduction : Hypertrophic scar is a devastating sequel to burns and other tangential skin injuries. It follows deep dermal injuries and does not occur after superficial injuries. Nitric oxide (NO) plays many important roles in wound healing from inflammation to scar remodeling. Studies have shown that expression of nitric oxide synthase and nitric oxide production are decreased in human hypertrophic scar. However little is known about NO involvement in the early stages of hypertrophic scarring, because of the lack of an animal model. It was recently reported that the female red Duroc pig (FRDP) makes thick scar, which is similar to human hypertrophic scar. We hypothesized that NO production in wounds on the female, red Duroc pig is similar to that of human hypertrophic scar and that NO involvement in deep wounds is different from that in superficial wounds. Methods : Superficial (0.015” to 0.030”) and deep (0.045” to 0.060”) wounds were created on the backs of four FRDPs. Biopsies were collected at weeks 1.5, 4, 8 and 21 post wounding including samples of uninjured skin. Nitric oxide levels were measured with the Griess reaction assay and normalized with tissue protein level. Results : Superficial wounds healed with an invisible scar whereas the deep wounds healed with scar resembling mild hypertrophic scar. The thickness of the scars from the deep wounds was significantly greater than uninjured skin and healed superficial wounds (p < 0.01). NO levels were increased at 1.5 weeks in deep wounds compared to superficial wounds and uninjured skin (p < 0.05). At 8 weeks, NO levels in deep wounds had returned to the level of uninjured tissue and superficial wounds. By 21 weeks, NO levels had decreased significantly when compared to superficial wounds (p < 0.01). There were no differences in NO levels between uninjured skin and superficial wounds at any time point (p > 0.05). Conclusions : NO production is similar in late, deep wounds on the female, red Duroc pig to that reported in the literature for human hypertrophic scar further validating this animal model. NO production is quite different after deep wounds as compared to superficial wounds in the FRDP. Early elevation in nitric oxide production might account for excessive inflammation in deep wounds that become thick scars in the FRDP. Nitric oxide regulators and effects at early stages of scar formation should be elucidated further and the FRDP appears to be a useful model.     

Active surveillance is superior to radical nephrectomy and equivalent to partial nephrectomy for preserving renal function in patients with small renal masses: Results from the DISSRM registry

Purpose

We compared renal function outcomes among patients in the surveillance and intervention arms of the DISSRM registry.

Progesterone for the prevention of preterm birth in women with multiple pregnancies: the AMPHIA trial

Background

Adequate vitamin D concentrations during pregnancy are necessary to neonatal calcium homeostasis, bone maturation and mineralization. The aim of study is to evaluate serum vitamin D concentrations in mothers and their newborns and effect of vitamin D deficiency on pregnancy outcomes.

Methods

552 pregnant women were recruited from Tehran University educating hospitals in the winter of 2002. Maternal and cord blood samples were taken at delivery. The serum was assayed for 25-hydroxyvitamin D3, calcium, phosphorus and parathyroid hormone.

Results

The prevalence of vitamin D deficiency in maternal and cord blood samples were 66.8% and 93.3%, respectively (<35 nmol/l). There was significant correlation between maternal and cord blood serum concentrations of vitamin D. In mothers with vitamin D deficiency, cord blood vitamin D concentrations was lower than those from normal mothers (P = .001). Also, a significant direct correlation was seen between maternal vitamin D intake and weight gain during pregnancy.

Conclusion

Consideration to adequate calcium and vitamin D intake during pregnancy is essential. Furthermore, we think it is necessary to reconsider the recommendation for vitamin D supplementation for women during pregnancy.     

Determinants of vancomycin clearance by continuous venovenous hemofiltration and continuous venovenous hemodialysis

The clearance of vancomycin is significantly reduced in patients with acute, as well as, chronic renal failure. Although multiple-dosage regimen adjustment techniques have been proposed for these patients, there is little quantitative data to guide the individualization of vancomycin therapy in acute renal failure patients who are receiving continuous renal replacement therapy (CRRT). To determine appropriate vancomycin dosing strategies for patients receiving continuous venovenous hemofiltration (CVVH) and continuous venovenous hemodialysis (CVVHD), we performed controlled clearance studies in five stable hemodialysis patients with three hemofilters: an acrylonitrile copolymer 0.6 m2 (AN69), polymethylmethacrylate 2.1 m2 (PMMA), and polysulfone 0.65 m2 (PS). Patients received 500 mg of vancomycin intravenously at least 12 hours before the start of the clearance study. The concentration of vancomycin in multiple plasma and dialysate/ultrafiltrate samples was determined by EMIT (Syva, Palo Alto, CA). The diffusional clearance and sieving coefficient (SC) of vancomycin were compared by a mixed-model repeated-measures analysis of variance (ANOVA) with filter and blood (Q(B)), dialysate inflow (Q(DI)), or ultrafiltration rate (Q(UF)) as the main effects and patient as a random effect. Vancomycin was moderately protein bound in these patients; free fraction ranged from 49% to 83%. The SCs of the three filters were similar and significantly correlated with the free fraction of vancomycin (P = 0.01; r2 = 0.465). Significant linear relationships were observed between the diffusional clearance of vancomycin and Q(DI) for all three filters: AN69 (slope = 0.482; r2 = 0.880); PMMA (slope = 0.853; r2 = 0.966); and PS (slope = 0.658; r2 = 0.887). The slope of this relationship for the PMMA filter was significantly greater than that of the AN69 and PS filters. The clearance of vancomycin, urea, and creatinine, however, was essentially constant at all Q(B)s for all three filters. Thus, the clearance of vancomycin was not membrane dependent during CVVH. However, during CVVHD, membrane dependence of vancomycin clearance was noted at a Q(DI) greater than 16.7 mL/min; vancomycin clearance with PMMA at a Q(DI) of 25 mL/min was 66% and 43% greater than that with the AN69 and PS filters, respectively. CVVH (62% to 262%) and CVVHD (90% to 540%) can significantly augment the clearance of vancomycin in acute renal failure patients. Dosing strategies for individualization of vancomycin therapy in patients receiving CVVH and CVVHD are proposed.     

Effects of CRL 41034 on the adrenergic neuroeffector interaction in the canine saphenous vein

Experiments were designed to determine the effect of CRL 41034, a buflomedil analogue, on the adrenergic responsiveness of canine veins. Rings of saphenous vein (without endothelium) were suspended for isometric tension recording in modified Krebs-Ringer bicarbonate solution at 37 degrees C. CRL 41034 produced a concentration-dependent inhibition of the contractions evoked by the alpha adrenergic agonists norepinephrine, phenylephrine and UK 14304 which was insensitive to the blockade of neuronal uptake by cocaine. CRL 41034 was more potent in inhibiting the concentration-dependent contractions evoked by UK 14304 than those by phenylephrine and the antagonism it caused against the response to UK 14304 fulfilled the criteria for competitivity. CRL 41034, at 10(-5) M significantly depressed, and at 10(-4) M abolished the contractions induced by electrical stimulation of the adrenergic nerves and those evoked by the indirect sympathomimetic amine tyramine. Strips of canine saphenous vein were superfused after incubation with [3H] norepinephrine. During sympathetic nerve activation, CRL 41304 increased the stimulation-evoked overflow of [3H] norepinephrine and 3-methoxy-4-dihydroxyphenylglycol; in the presence of rauwolscine the compound only increased the stimulation-evoked overflow of 3,4-dihydroxyphenylglycol. These experiments suggest that the major vascular effects of CRL 41034 in canine veins are blockade of alpha 2-adrenoceptors on vascular smooth muscle, and inhibition of prejunctional alpha 2-adrenoceptors on adrenergic nerve endings.