生长与生长激素治疗还有新进展吗?

矮身材十分常见,而就诊者中由内分泌原因所致者不到5％。随时更新的、按不同种族制订的生长曲线图是评价儿童生长状况最重要的工具。矮身材的传统定义为身高低于正常生长曲线的第3百分位数,但实际上在此范围内大部分儿童是完全正常的。若采用0．4百分位数作为身材矮小的临界值,则其中1／3～1／2的儿童确有生长障碍。     

Postoperative mediastinitis in children: epidemiology, microbiology and risk factors for Gram-negative pathogens

BACKGROUND: Mediastinitis, although an infrequent complication of median sternotomy, represents a significant source of morbidity and mortality. OBJECTIVE: To determine the incidence and describe the epidemiology and microbiology of mediastinitis in children after cardiac surgery and to identify risk factors for the development of Gram-negative mediastinitis. STUDY DESIGN: This was a retrospective case-control study nested within the cohort of children, birth to 18 years of age, undergoing median sternotomy between January 1, 1995 and December 31, 2003. RESULTS: Forty-three cases of mediastinitis were identified. The incidence of mediastinitis was 1.4%. Median patient age at time of inciting sternotomy was 32 days (interquartile range, 5 days-9 months). Twenty-three (54%) cases occurred in girls. Median time to onset of infection after surgery was 11 days (range, 4-34 days). Overall Gram-positive organisms were present in 29 (67%) cases, and Gram-negative organisms were present in 13 (30%) cases. The organisms most commonly isolated from mediastinal culture were Staphylococcus aureus (46%), coagulase-negative staphylococci (17%) and Pseudomonas aeruginosa (17%). The rate of concurrent bacteremia was 53% (95% confidence interval, 38-69%). In multivariable analysis, delayed sternal closure was an independent risk factor for the development of Gram-negative mediastinitis (odds ratio, 9.3; 95% confidence interval, 1.5-56.8; P = 0.016). CONCLUSIONS: Although Gram-positive organisms were the most common cause of infection, Gram-negative organisms accounted for one-third of all isolates. More than one-half of patients with mediastinitis had concurrent bacteremia. Delayed sternal closure was an independent risk factor for Gram-negative mediastinitis.     

Suppurative intracranial complications of sinusitis in previously healthy children

In this retrospective case series, we describe the clinical features and microbiology of 16 previously healthy children with suppurative intracranial complications of sinusitis. Most cases were male adolescents who presented with vomiting in addition to typical sinusitis symptoms. Neurologic signs were often absent. Streptococcus milleri group organisms, along with anaerobes, were common pathogens.     

Increased pulmonary artery pressures among adolescents with sickle cell disease

The prevalence of pulmonary hypertension (PHT) among adolescents with sickle cell disease (SCD) is unknown. A tricuspid regurgitant (TR) jet peak velocity of 2.5 m/s or more is a screening test for PHT. The authors retrospectively reviewed echocardiograms and clinical data of adolescents followed at the Texas Children's Sickle Cell Center. Of 80 evaluable adolescents with SCD and echocardiogram data, 21 (26%) had a TR jet velocity of 2.5 m/s or more. Of these 21 patients with PHT, 12 (57%) had an echocardiogram performed during an inpatient stay for vaso-occlusive crisis (n = 6), acute chest syndrome (n = 4), fever (n = 1), or seizures (n = 1), and 9 (43%) had an echocardiogram performed as an outpatient in a baseline state of health. Elevation of pulmonary artery pressures was common in this adolescent cohort, but clinical symptoms were rare. Prospective study is warranted to determine the prevalence and course of elevated pulmonary artery pressures in this age group.     

Therapeutic choices in the current millennium: hemophilia workshop highlights

Many issues affect hemophilia care providers when managing bleeding episodes in individuals with hemophilia. A diverse group of hemophilia providers from the United States met at two workshops to discuss the issues influencing treatment choices in the current millennium and to learn about current advances in treatment of hemophilia. This paper provides a summary of the discussions at these workshops. Despite the progress made in the management of patients with hemophilia, the workshop highlighted the fact that there were still many unanswered questions.     

Maternal nonpregnant vascular function correlates with subsequent fetal growth

OBJECTIVE: Evidence is accumulating that fetal growth is influenced by preexisting maternal disorder(s) hampering endothelial function. We tested the hypothesis that in nonpregnant normotensive, formerly preeclamptic women, vascular function predicts the development of fetal growth restriction. METHODS: In 60 formerly preeclamptic women, we measured central hemodynamic and vascular and clotting function mid follicular phase during the menstrual cycle. Inclusion for final analysis required besides normotension, a subsequent singleton pregnancy, established within 1 year after the prepregnant evaluation and ongoing beyond 16 weeks' gestation. In the ongoing pregnancy we determined birth weight and birth weight percentile. RESULTS: Among 60 formerly preeclamptic women, 45 (75%) were normotensive. Thirty-one (69%) participants succeeded in establishing an ongoing pregnancy within 1 year and were included for final analysis. Of the 31 subsequent pregnancies, 8 (26%) were complicated by fetal growth restriction. Prepregnant left and right uterine artery pulsatility index (PI) correlated inversely with carotid artery compliance ( r = 0.57, P = .005, r = 0.62, P = .002) and venous compliance ( r = 0.49, P = .02 and r = 0.45, P = .04, respectively). The latter, in turn, correlates with plasma volume ( r = 0.63, P = .001) and total peripheral vascular resistance index ( r = -0.45, P = .02). Finally, prepregnant left and right uterine artery PI correlated inversely with subsequent achieved fetal growth ( r = -0.68, P < .0001 and r = -0.58, P = .001, respectively). CONCLUSION: In nonpregnant normotensive, formerly preeclamptic women, an elevated uterine artery PI predisposes to subsequent restriction in fetal growth.     

Clinical, microbiological, and immunological characteristics in HIV-infected subjects at risk for disseminated Mycobacterium avium complex disease: an AACTG study

The clinical, microbiologic, and immunologic parameters in HIV-infected subjects first presenting with disseminated Mycobacterium avium complex (DMAC) were determined. Four HIV-positive groups not yet on DMAC treatment were enrolled: 19 subjects with CD4 lymphocyte counts < or =50/microl thought to have DMAC on clinical grounds; 18 subjects newly found to have a positive blood culture for MAC; 25 asymptomatic controls (CD4 cell counts < or =50); and 25 asymptomatic controls (CD4 counts 100-250/microl). Outcome measures include comparisons between groups for clinical characteristics; results of cultures from blood, marrow, and gastrointestinal and respiratory tracts; immunological markers from staining of marrow and flow cytometry of circulating lymphocytes; and cytokine production of PBMCs. Only 21% of the 19 patients entered on suspicion of having DMAC grew MAC from blood or marrow. Neither clinical presentation nor laboratory tests differentiated those culture-positive from those culture-negative patients. However, prior PCP or multiple other opportunistic infections were more common in the DMAC group. MAC was isolated from 82% of marrow and 50% of blood specimens from the DMAC group. Respiratory or gastrointestinal colonization was present in 36% of DMAC subjects, but only 5% of non-DMAC subjects with CD4 counts <50 cells/microl. CD8+ cells were more frequent in bone marrow, and CD4 cells recognizing MAC antigen were more frequent in blood from DMAC subjects vs. controls. Results suggest an early stage of tissue dissemination preceding persistent bacteremia, and mucosal entry without persistence of colonization. MAC-specific T cell responses apparently develop and persist during DMAC, but are dysfunctional or too infrequent to prevent persistence.     

Pathological aging of the vascular endothelium: are endothelial progenitor cells the sentinels of the cardiovascular system?

Aging is associated with vascular endothelial dysfunction, which ultimately leads to atherosclerosis. On the other hand, it is clear that in young patients with risk factors for cardiovascular diseases (CVD), endothelial dysfunction is an early marker of the ongoing atherogenic process. It is therefore tempting to speculate that risk factors for CVD accelerate the aging process. The aging of an endothelial cell (EC) is not chronological but rather dependent on its replication rate. ECs have a finite number of divisions and enter replicative senescence after exhaustion of this potential. Telomere attrition is believed to be responsible for this phenomenon. Upon reaching a critical minimal telomere length, ECs enter a nondividing state of replicative senescence. Recently, endothelial progenitor cells originating from the bone marrow have been isolated from the circulation. They integrate into the endothelial layer of the vessel and contribute to healing, ischemic repair and angiogenesis. A completely new field of investigation is now open. Are endothelial progenitor cells sensitive to the aging process? Do they prevent endothelial dysfunction? Are they the ultimate shield against the damages induced by risk factors for CVD? There are no definite answers to these questions, but the potential of these cells is tremendous and understanding their physiology is essential.