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.     

Impact of mitral valve annuloplasty combined with revascularization in patients with functional ischemic mitral regurgitation.

OBJECTIVES: The aim of this work was to determine whether mitral valve (MV) annuloplasty benefits patients with moderate/severe (3+/4+) functional ischemic mitral regurgitation (MR) who undergo coronary artery bypass grafting (CABG). BACKGROUND: Mitral regurgitation is a strong predictor of poor outcomes in patients with ischemic cardiomyopathy; whether correcting it at the time of CABG improves outcomes is less certain. METHODS: From 1991 to 2003, 390 patients with 3+/4+ ischemic MR had CABG with (n = 290) or without (n = 100) MV annuloplasty. Groups were propensity-matched using demographics, extent of coronary disease, regional wall motion, and quantitative electrocardiography. Survival, echocardiographic severity of MR, and New York Heart Association (NYHA) functional class were compared. RESULTS: One-, 5-, and 10-year survival was 88%, 75%, and 47% after CABG alone and 92%, 74%, and 39% after CABG + MV annuloplasty (p = 0.6). Mortality was increased in patients with severe lateral wall motion abnormalities (p = 0.05), ST-segment elevation in lateral leads (p < 0.004), and higher QRS voltage sum (p < 0.0001). Patients undergoing CABG alone were more likely to have 3+/4+ postoperative MR than those undergoing CABG + MV annuloplasty (48% vs. 12% at 1 year, p < 0.0001). The NYHA functional class substantially improved in both groups (p < 0.001) and remained improved; at 5 years, 23% of patients having CABG + mitral annuloplasty and 25% having CABG alone were in NYHA functional class III/IV. CONCLUSIONS: Although CABG + MV annuloplasty reduces postoperative MR and improves early symptoms compared with CABG alone, it does not improve long-term functional status or survival in patients with severe functional ischemic MR. The MV annuloplasty in this setting, without addressing fundamental ventricular pathology, is insufficient to improve long-term clinical outcomes.     

Evaluation of bedside blood glucose monitoring by the phlebotomy team in an acute general care hospital

A feasibility study was undertaken to evaluate laboratory phlebotomists performing bedside glucose monitoring (BGM) over a 3-month period on a medical and surgical floor. Specific questions included: feasibility of providing testing on a 24-h basis, accuracy, appropriate utilization, effect on patient care, and an analysis of cost. In all, 1975 tests were performed on 114 patients. BGM results were within 15% of the laboratory's result 97% of the time. Patient and physician satisfaction was high. Although the cost of BGM is slightly higher than a laboratory glucose test, its use appeared to reduce the length of hospital stay by 0.47 days. Practical information on initiating a highly successful BGM program is provided.     

Usefulness of real-time three-dimensional echocardiography for evaluation of myectomy in patients with hypertrophic cardiomyopathy

Real-time 3-dimensional echocardiography was performed in 10 patients with obstructive hypertrophic cardiomyopathy (HC) before and after myectomy and in 6 controls. The exact location of systolic anterior motion of the mitral leaflet was shown in all patients with HC with a predominant involvement of the medial portion in 4 patients and the middle portion in 6 patients. The smallest area of the left ventricular outflow tract was significantly smaller in patients with HC than in controls (1.4 +/- 0.7 vs 5.1 +/- 1.2 cm(2), p <0.01), significantly increased after myectomy (4.8 +/- 1.8 cm2, p <0.01) and was associated with a reduction of the pressure gradient at rest from 63 +/- 41 to 15 +/- 5 mm Hg (p <0.01).     

Conduction system abnormalities in patients with obstructive hypertrophic cardiomyopathy following septal reduction interventions

We observed the impact of percutaneous transluminal septal myocardial ablation (PTSMA) and myectomy on the conduction system in patients with obstructive hypertrophic cardiomyopathy (HC). Septal reduction intervention is capable of eliminating the left ventricular outflow tract obstruction in patients with obstructive HC; however, conduction system abnormalities are frequent consequences of these procedures. A standard 12-lead electrocardiogram and Doppler echocardiogram were obtained in 204 patients who underwent PTSMA (n = 70) or myectomy (n = 134) before and at average of 3 months after intervention. Of 146 patients who had normal conduction systems before intervention, the duration of the QRS complex was significantly prolonged from 98 +/- 15 to 130 +/- 25 ms (p <0.0001), with right bundle branch block (RBBB) developing in 62% patients after PTSMA, and from 100 +/- 13 to 154 +/- 20 ms (p <0.0001), with left bundle branch block (LBBB) developing in 93% patients after myectomy. No significant difference in the QRS duration was found in the remaining 58 patients who had preexisting conduction abnormalities after intervention. In 174 patients without a preexisting permanent pacemaker, a pacemaker was implanted in 22% versus 13% of patients who underwent PTSMA (overall and without preexisting conduction block, respectively) and 10% versus 2% of patients with myectomy. The duration of baseline QRS was an independent predictor for the requirement of a permanent pacemaker (p <0.0001). Thus, RBBB often develops after PTSMA and LBBB is very frequently produced by myectomy. A possible requirement of a permanent pacemaker should always be considered before intervention when patients have preexisting RBBB or LBBB.     

Residues within a lipid-associated segment of the PECAM-1 cytoplasmic domain are susceptible to inducible, sequential phosphorylation

Immunoreceptor tyrosine-based inhibitory motif (ITIM)-containing receptors inhibit cellular responsiveness to immunoreceptor tyrosine-based activation motif (ITAM)-linked receptors. Although tyrosine phosphorylation is central to the initiation of both inhibitory ITIM and stimulatory ITAM signaling, the events that regulate receptor phosphorylation are incompletely understood. Previous studies have shown that ITAM tyrosines engage in structure-inducing interactions with the plasma membrane that must be relieved for phosphorylation to occur. Whether ITIM phosphorylation is similarly regulated and the mechanisms responsible for release from plasma membrane interactions to enable phosphorylation, however, have not been defined. PECAM-1 is a dual ITIM-containing receptor that inhibits ITAM-dependent responses in hematopoietic cells. We found that the PECAM-1 cytoplasmic domain is unstructured in an aqueous environment but adopts an α-helical conformation within a localized region on interaction with lipid vesicles that mimic the plasma membrane. The lipid-interacting segment contains the C-terminal ITIM tyrosine and a serine residue that undergo activation-dependent phosphorylation. The N-terminal ITIM is excluded from the lipid-interacting segment, and its phosphorylation is secondary to phosphorylation of the membrane-interacting C-terminal ITIM. On the basis of these findings, we propose a novel model for regulation of inhibitory signaling by ITIM-containing receptors that relies on reversible plasma membrane interactions and sequential ITIM phosphorylation.     

Willingness to participate in cardiac trials

The elderly, women, and minorities are all less likely to be enrolled in randomized clinical trials (RCTs). Whether differential patient interest in RCTs contributes to these disparities is unclear. The authors surveyed 660 patients' willingness to consider two potential cardiac RCTs of medical therapy vs. percutaneous coronary angioplasty or coronary artery bypass surgery, respectively. The cohort's mean age was 67 years (43% aged ≥70 years; 35% women; and 28% nonwhite). Compared with younger patients, those aged ≥70 years were equal or more likely to consider both the percutaneous coronary angioplasty (46% vs. 41%) and coronary artery bypass surgery RCTs (35% vs. 31%). Race also had no significant impact on trial enrollment, yet women were significantly less likely than men to participate in either RCT. In conclusion, patient willingness to consider RCT participation does not explain underenrollment of elderly and minority patients. Women, however, were more reluctant to consider RCTs, an area requiring further study.     

Effect of cardiac rehabilitation on functional outcomes after coronary revascularization

Background Current guidelines recommending cardiac rehabilitation (CR) after coronary revascularization are largely based on early studies that evaluated only a subset of the population and failed to assess the impact of CR on a patient's perception of their functional status. The main objective of this study was to evaluate the impact of CR in a diverse contemporary population on patient functional outcomes. Methods We studied the effect of CR on 6-month SF-36 Physical Functioning (PF) in 700 patients (mean age 67 ± 11 years, 37% women) who underwent coronary bypass grafting or percutaneous intervention from August 1998 to July 2000. Results Overall CR participation was 24%. At baseline, CR participants had higher PF (mean 62.5 vs 52.5, P < .001). After adjusting for baseline clinical variables and PF score, CR was associated with significant improvement in 6-month PF (+5.0, 95% CI 1.0-9.0). This improvement was observed in all patient subgroups, but tended to be greater in magnitude in men versus women, patients aged <70 years versus ≥70 years, and patients with coronary bypass grafting versus patients with percutaneous intervention. CR participants also tended to be more likely to engage in regular exercise (63% vs 55%, P = .06) and modify their diet (82% vs 73%, P = .07). Rates of rehospitalization and repeat revascularization were similar among CR participants and nonparticipants. Conclusions CR after coronary revascularization is associated with improved functional outcomes and adoption of secondary preventive measures. Innovative strategies to facilitate CR enrollment and tailoring programs to better address the needs of all patient subgroups would extend these benefits to more eligible patients. (Am Heart J 2003;145:445-51.)     

Angiogenic factors stimulate mast-cell migration

Mast cells accumulate at sites of angiogenesis. The factor(s) that control mast-cell recruitment at these sites have yet to be defined. We sought to determine if angiogenic factors result in mast-cell chemotaxis. In this study, we observed that platelet-derived growth factor-AB (PDGF-AB), vascular endothelial cell growth factor (VEGF), and basic fibroblast growth factor (bFGF) each cause directed migration of murine mast cells at picomolar concentrations, with a typical bell- shaped dose-response curve. Another potent angiogenic factor, platelet- derived endothelial cell growth factor (PD-ECGF), appears to promote chemokinesis of mast cells, whereas tumor necrosis factor-alpha, a weak angiogenic factor, is less robust but still functions as a mast cell chemotactic factor. Epidermal growth factor (EGF), a growth factor with minimal angiogenic properties, was ineffective as a mast cell chemotactic factor. A checkerboard analysis confirmed the directional chemotactic response of PDGF-AB, VEGF, and bFGF, while indicating the chemokinetic response induced by PD-ECGF. Cross-desensitization of growth-factor-induced directed migration was observed between PDGF-AB and bFGF, and also between PDGF-AB and PD-ECGF. Tyrosine kinase- inhibitor genistein effectively dampened the chemotactic responses, whereas pertussis toxin had no effect. In summary, our findings suggest that factors known to act on endothelial cells and stimulate neovascularization may simultaneously serve to recruit mast cells to these sites. The local accumulation of mast cells is believed to facilitate new vessel formation through complex cell:cell interactions.