The electrophysiologic effects of propafenone hydrochloride in the neonatal canine

The electrophysiologic effects of the new antiarrhythmic agent, propafenone, were investigated in 10 mongrel canine neonates, ages 5 to 11 days. Utilizing standard His bundle recording and stimulation techniques, assessments of sinus and atrioventricular (AV) node function and atrial, AV nodal, and ventricular refractory periods were performed prior to (control) and after cumulative intravenous doses of 1, 2, and 4 mg/kg of propafenone. Propafenone depressed the spontaneous heart rate and prolonged the postatrial pacing recovery times. AV nodal function was depressed as manifested by Wenckebach periodicity occurring at slower pacing rates, increases in AV nodal conduction time, and increases in AV nodal refractoriness. Atrial and ventricular refractory periods were prolonged significantly in a dose-dependent fashion. Prolongation of the His-Purkinje conduction time occurred at the highest dose. Thus, propafenone exerts a generalized depressant effect on neonatal myocardial conduction and refractoriness which suggests that this agent may be useful in the therapy of atrial and ventricular dysrhythmias in the immature heart.     

Atrioventricular nodal function in the immature canine heart [corrected and republished article orginally printed in Pediatr Res 1987 Nov;22(5):616-20

Previous studies have suggested that the atrioventricular nodal functional refractory period in the neonate is equal to or shorter than that of the ventricle, providing little or no protection to the ventricle against rapid atrial rates and allowing closely coupled atrial beats to fall within the ventricular vulnerable period. We evaluated atrioventricular node function in 21 mongrel neonatal puppies, 3-15 days old, and 15 adult dogs utilizing intracardiac His bundle recording and stimulation techniques. The mean atrioventricular nodal functional refractory period (173.1 +/- 20.0 ms) exceeded both the ventricular effective refractory period (139.5 +/- 14.3) and ventricular functional refractory period (163.3 +/- 14.5) in the neonates. Furthermore, the atrioventricular node was the site of limiting antegrade conduction in all neonates. No ventricular arrhythmias were induced by atrial extrastimulation in any of the neonates. The site of conduction delay during atrial extrastimulation was confined to the atrioventricular node in 15/16 neonates (94%) while 1/16 (6%) had combined nodal and infranodal delay. The neonates developed Wenckebach, at significantly faster heart rates than the adults, but both groups developed Wenckebach at approximately twice the resting heart rate. Retrograde conduction was a consistent finding in the neonates. However, antegrade Wenckebach occurred at a significantly faster heart rate than retrograde Wenckebach suggesting different functional properties. Our data suggest that in the neonatal canine, the atrioventricular node functional refractory period is longer than both the ventricular effective refractory period and ventricular functional refractory period. Furthermore, the degree of protection offered by the neonatal atrioventricular node to the ventricle appears to be comparable to that of the adult.     

Heart rate and heart rhythm in healthy infants and children

Cardiac rate and rhythm in 141 healthy infants, toddlers and schoolchildren during 24 hour ambulatory electrocardiographic monitoring are reported. Maximal and minimal heart rate (1/min) in infants 1 to 5 months of age were 204 +/- 17 and 105 +/- 13, in infants 6 to 12 months of age 187 +/- 19 and 101 +/- 15; in toddlers 177 +/- 17 and 66 +/- 10; in schoolchildren 158 +/- 24 and 54 +/- 6. A sizeable proportion of children of all age groups showed patterns of sinus arrhythmias indistinguishable from second degree sinuatrial block. Supraventricular escape beats and escape rhythms were frequent as well. The longest RR interval was 1.03 +/- 0.16 sec. in infants, 1.20 +/- 0.25 sec. in toddlers, and 1.35 +/- 0.15 sec., respectively, in schoolchildren. Two % of infants, 7% of toddlers, and 6% of schoolchildren had episodes of second degree atrioventricular block type I (Wenckebach) at rest. Supraventricular extrasystoles were found in 38%, 13% and 26%, respectively, and uniform ventricular extrasystoles in 18%, 20% and 16%, respectively, of infants, toddlers and schoolchildren. These data, together with similar information in the literature, can be taken as basis for the evaluation of ambulatory electrocardiograms in children.     

Ultrasound assessment of ductal closure, pulmonary blood flow velocity, and systolic pulmonary arterial pressure in healthy neonates

Ultrasound Doppler was used to establish time of ductal closure, normal values for blood flow velocity in the pulmonary artery (PA), and time interval between pulmonary valve closure (Pc) and tricuspid valve opening (To) in 37 healthy neonates. Ductal closure had occurred in 23% of the children within 12 h after delivery and in 53% during the next 12 h. No open ductus was found after 30 h of age. Maximal blood flow velocity was 0.90 +/- 0.09 (SD) m/s during the first five days of life and 1.12 +/- 0.17 m/s at the age of 14-30 days. The Pc-To interval is known to reflect systolic PA pressure in adults. The Pc-To interval decreased significantly (p less than 0.01) from an average of 0.059 +/- 0.016 s at 3.5-12 h of age to 0.048 +/- 0.011 at 19-36 h of age and thereafter successively to 0.027 +/- 0.004 s at 20-30 days of age. This value is only slightly higher than that of 0.015-0.020 s for normal adults at comparable heart rates. These data suggest a rather sharp decline of systolic PA pressure during the first day of life and thereafter a slower decline; normal adult values are approached but not reached at 3-4 weeks of age. The Pc-To value seems to be of limited value in the early neonatal period, because even normal neonates have increased values with a large individual variation. After 3-4 weeks of age, an increased value should be taken as an indication of increased systolic PA pressure.     

Developmental changes of plasma ganglioside concentration during the neonatal period

We investigated the developmental changes of plasma ganglioside concentration during the neonatal period. The mean plasma ganglioside concentration at birth was 8.22 +/- 3.70 nmol lipid-bound sialic acid (LBSA)/ml, significantly lower than the value in adults (12.05 +/- 1.36 nmol LBSA/ml, P less than 0.02). However, it increased rapidly early in the neonatal period and reached its maximum level at 14 days of age (16.25 +/- 6.04 nmol LBSA/ml), which was higher than that of adults (P less than 0.05); then it decreased slowly to the adult level at one month of age. The mean plasma ganglioside concentration in preterm infants (gestational age less than 37 weeks) was 6.65 +/- 3.35 nmol LBSA/ml, somewhat lower than that of fullterm infants (gestational age greater than or equal to 37 weeks, 9.90 +/- 3.39 nmol LBSA/ml, P less than 0.02) at birth. After birth, it increased much more rapidly in preterm infants and there was no significant difference between these two groups at 5 days of age. Plasma ganglioside concentration at birth increased gradually in correlation with gestational age. Our investigations show that plasma ganglioside concentration may reflect the development and maturation of the central nervous system to some degree, at least early in the neonatal period.     

The efficacy of two different lipid-based amphotericin B in neonatal Candida septicemia

BACKGROUND: Fungal sepsis is becoming more frequent in neonatal intensive care units (NICU) and has a high mortality rate due to the invasive nature of the disease and to the insufficiency of low doses and high incidence of renal problems with effective doses of amphotericin B. New generation lipid formulated amphotericin B preparations may be more efficient because they are less toxic to be applied in target doses. However, there is limited experience in neonates and preterm infants. METHODS: The charts of 917 patients admitted to NICU between 2001 and 2003 were reviewed and the data of 21 patients with systemic Candida infection, requiring different amphotericin B therapy, were analyzed. RESULTS: Infants with fungal septicemia were treated with amphotericin B lipid complex (Abelcet)(n = 10) and liposomal amphotericin B (AmBisome)(n = 9) for a mean duration of 21 and 18 days. The mean gestational age of the patients was 30.9 +/- 4.2 weeks and mean birth weight was 1536 +/- 714 g. Two patients in the Abelcet group and one patient in the AmBisome group died during therapy. Fungal eradication was achieved in 16 surviving infants and mean eradication time was 8.1 +/- 2.6 days and mean duration of therapy was 19.2 +/- 4.1 days. Mortality rates related to treatment failure were similar being 20% in the Abelcet group and 11% in the AmBisome group. No patient showed severe side-effects from the antifungal therapy; the incidence of minimal side-effects were similar in both groups and they were elevated serum transaminase levels in six patients, increased serum creatinine in one patient and hypokalemia in one patient. Conclusion: Both preparations have the same benefits for the treatment of neonatal fungal sepsis and they can be used safely in neonates including very low birth weight infants. However, the clinician must keep in mind the cost of treatment.     

Effects of hypoxia on the cellular electrical activity of adult and neonatal canine ventricular myocardium

Standard microelectrode techniques were utilized to evaluate the effects of acute hypoxia on the cellular electrical activity of neonatal and adult ventricular myocardium. Control action potential parameters from adult and neonatal tissues were not significantly different. Thirty minutes of acute hypoxic superfusion significantly (p less than 0.05) reduced all adult action potential indices. In neonatal preparations, only action potential duration at 50% repolarization (-17%) and action potential duration at 90% repolarization (-12%) were reduced significantly. After 60 min of hypoxia, action potential amplitude, maximum diastolic potential, and phase 0 upstroke velocity from neonates were still not reduced significantly. The alteration in neonatal action potential parameters induced by 1 h of hypoxic superfusion (5.5 mM glucose) were all reversed by 16.5 mM glucose despite continued hypoxia. Exclusion of glucose from the hypoxic superfusate did not greatly affect the response of neonatal tissues to hypoxia. In adult action potentials, the degree of decrease for each action potential parameter was markedly greater compared to the hypoxic solution with normal (5.5 mM) glucose. Following hypoxic superfusion of neonatal preparations with 0 mM glucose, reoxygenation with 16.5 mM glucose resulted in action potential parameters with exceeded control values by 4 to 25%. Our data indicate a greater resistance of developing myocardium to the detrimental effects of hypoxia on cellular electrical activity. This seems to be related to a greater glycolytic activity of neonatal myocardium compared to adult hearts.     

Developmental cellular electrophysiologic effects of d-sotalol on canine cardiac Purkinje fibers

d-Sotalol may be a clinically useful class III antiarrhythmic agent for controlling ventricular arrhythmias in children. Because age-related differences in repolarization currents may contribute to developmental differences in response to antiarrhythmic agents that primarily affect repolarization, the electrophysiologic effects of d-sotalol were compared in Purkinje fibers from neonatal and adult dogs. Significant age-related changes characterized the antiarrhythmic profile of d-sotalol. d-Sotalol (10(-4) M) significantly prolonged the action potential duration of adult Purkinje fibers (310 +/- 8 to 380 +/- 7 ms, p less than 0.01) and neonatal fibers (247 +/- 5 to 342 +/- 9 ms, p less than 0.01). However, the lengthening of action potential duration was significantly greater in the immature age group. d-Sotalol had no significant effect on maximum diastolic potential, action potential amplitude, or phase zero upstroke velocity in normally polarized fibers. In contrast, different electrophysiologic effects were observed in K(+)-depolarized Purkinje fibers. Superfusion of adult K(+)-depolarized fibers with d-sotalol suppressed excitability in five (38%) of 13 fibers and significantly decreased action potential amplitude (88 +/- 2 to 83 +/- 1 mV, p less than 0.05) and phase zero upstroke velocity (180 +/- 14 to 105 +/- 3 V/s, p less than 0.01) in the other eight fibers. The membrane depressant effects observed in the younger age group were significantly less [no suppression of excitability and a smaller decrease in phase zero upstroke velocity (121 +/- 22 to 101 +/- 23 V/s, p less than 0.05). The magnitude of action potential duration prolongation by d-sotalol in K(+)-depolarized fibers was less than in normally polarized fibers.(ABSTRACT TRUNCATED AT 250 WORDS)     

Cellular dehydration and immunoglobulin binding in senescent neonatal erythrocytes

The life span of neonatal erythrocytes (60-80 days) is shorter than that of adult erythrocytes (120 days). We studied neonatal red blood cells separated on stractan density gradients to further characterize the aging process and to explore the possibility that senescence antigens play a role in the destruction of neonatal erythrocytes. Quantitation of membrane proteins 4.1a and 4.1b served as a marker for cell age and confirmed an enrichment for senescent red cells in the most dense layers of the gradients. Despite the shorter life span of neonatal erythrocytes, cord blood contained a larger percentage of very dense, K+-depleted red cells than did adult blood. ATP levels in dense neonatal and adult cells were decreased to 50-80% of normal values for unseparated red cells. Levels of reduced glutathione did not fall with increasing cell density. Sodium dodecyl sulfate polyacrylamide gel electrophoresis of red cell membrane proteins showed increased membrane-associated globin in senescent neonatal cells, but such gels run without reducing agents did not show oxidative protein cross-linking. Membrane bound immunoglobulins were detected on senescent neonatal and adult red cells by the rosetting antiglobulin test. We conclude that senescence antigens are revealed during the aging process of neonatal erythrocytes, thereby labeling them for antibody-mediated destruction in the reticuloendothelial system.     

牵引在闭合复位治疗儿童发育性髋关节脱位中的作用的多中心回顾性研究

目的 探讨双下肢牵引在儿童发育性髋关节脱位(DDH)闭合复位中的作用.方法 回顾性分析我国南方7家医院2004年1月至2014年6月采用闭合复位治疗的DDH患儿的临床资料.共有302例(333髋)符合纳入标准,其中,男40例,女262例;单侧271例,双侧31例.平均年龄(16.5±5.1)个月,平均随访时间(38.0±18.0)个月.牵引组227例,非牵引组75例.比较两组患儿Tonnis分度、再脱位发生率、股骨头坏死(AVN)、末次随访髋臼指数(AI)、中心边缘角(CE角)和Severin影像学分级.结果 非牵引组平均住院时间(5.1±2.6)d,显著短于牵引组(16.2±7.5)d(P＜0.001).术前牵引组的平均Tonnis分度显著高于非牵引组(P=0.021).333髋中有23髋(6.9％)出现再脱位,牵引组的再脱位发生率为8.7％,非牵引组的再脱位发生率为1.3％,两者差异有统计学意义(P=0.022).在Tonnis Ⅱ度的患儿中,牵引组和非牵引组的再脱位发生率差异无统计学意义.在Tonnis Ⅲ～Ⅳ度的患儿中,牵引组的再脱位发生率显著高于非牵引组(P=0.027).牵引组AVN发生率为17.4％,非牵引组AVN发生率为26.3％,两者差异无统计学意义(P =0.083).同样,根据Tonnis分型分别比较牵引和非牵引组之间的AVN发生率,结果差异也无统计学意义.牵引和非牵引组之间AVN的分型差异也无统计学意义(P=0.076).牵引组和非牵引组之间的AI值和CE角差异均无统计学意义(P＞0.05).两组之间Severin影像学分级差异无统计学意义(P =0.559).结论 牵引不能降低DDH闭合复位术后再脱位的发生率,不能减少AVN的发生率,也不能改善DDH闭合复位的最终治疗效果.     

Chronic Left Ventricular Pacing Preserves Left Ventricular Function in Children

Chronic right ventricular (RV) pacing can induce structural and functional cardiac deterioration. Because animal studies showed a benefit of left ventricular (LV) over RV pacing, this study compared the effects of chronic RV and LV pacing in children. Retrospectively, echocardiographic data were evaluated from 18 healthy children (control subjects) and from children undergoing chronic epicardial RV pacing (7 RVP) or LV pacing (7 LVP). Assessment included LV end-diastolic wall thickness (LVEDWT) and end-systolic wall thickness (LVESWT) as well as LV end-diastolic diameter (LVEDD) and end-systolic diameter (LVESD). The shortening fraction and eccentricity index (LV diameter/2xLV wall thickness) were calculated as measures of LV function and eccentricity, respectively. Duration of QRS and septal posterior wall motion delay (SPWMD) were used as measures of electrical and mechanical dyssynchrony, respectively. A p value less than 0.05 determined significance. As the findings showed, LVEDD, LVESD, LVEDWT, and LVESWT were not significantly different between the groups. The shortening fraction was significantly lower in the RVP (21.7%+/-6.0%) than in the LVP (32.2%+/-5.2%) or control (29.3%+/-4.3%) children. The systolic LV eccentricity index was significantly larger in the RVP (1.8+/-0.2) than in the LVP (1.4+/-0.1) or control (1.4+/-0.2) children. The SPWMD was significantly larger in the RVP (338+/-20 ms) than in the LVP (-16+/-14 ms) or control (-5+/-35 ms) group, whereas QRS duration was similarly longer in the RVP (157+/-10 ms) and LVP (158+/-22 ms) groups compared than in the control group (69+/-7 ms). The authors conclude that LV function in children is preserved by chronic pacing at the LV lateral wall.     

Drug utilisation in very preterm infants: any changes during the past decade?

BACKGROUND: Improved standards of perinatal care for preterm infants led to decreased hospital mortality rates during the past decade. However, studies investigating changes in drug utilisation in neonatal intensive care units (NICU) during this period are missing. OBJECTIVE: The aim of the present study therefore was to evaluate the most frequently used groups of drugs in preterm infants treated in NICUs and to analyse potential changes in drug utilisation over a period of ten years. METHODS: Drug utilisation patterns in 164 preterm infants born between 1989 and 1990 (group I; gestational age 27.2+/-1.2 weeks, birth weight 970+/-145 g) were compared to those in 113 preterm infants born between 2001 and 2004 (group II; gestational age 26.9+/-1.65 weeks, birth weight 930+/-253 g, mean and standard deviation each) with need for postnatal mechanical ventilation. RESULTS: Significant changes in drug utilisation patterns were observed for complete courses of antenatal corticosteroids (40 vs. 51.5%), diuretics (78 vs. 36.6%), surfactant (63.3 vs. 75%), methylxanthines (89.9 vs. 56.7%), sedatives/analgesics (82.4 vs. 91.5%) and catecholamines (38.3 vs. 52.4%) (group II vs. group I each). Postnatal corticosteroids were applied more often in group II (17.4 vs. 13.4%). However, duration of postnatal corticosteroid treatment has decreased (6 d vs. 13 d). The use of antibiotics remained unchanged (100 vs. 98.9%). Comparison of clinical outcome variables showed a decreased duration of mechanical ventilation and a significantly increased survival rate. CONCLUSION: Drug utilisation patterns in preterms have changed considerably during the past decade. Improved standards of care and shorter duration of mechanical ventilation may be operative.     

The treatment of arrhythmias in infants and children using propafenone

Antiarrhythmic treatment was required in 35 patients aged one day to 11 8/12 years (average 5 7/12 years) for one or several of the following arrhythmias: paroxysmal supraventricular tachycardia (17), ventricular extrasystole (16), ventricular tachycardia (17), ventricular extrasystole (16), ventricular tachycardia (4), junctional tachycardia (4), and atrial flutter (3). 300 mg/m2/day oral propafenone was administered in 3 to 4 divided doses. The arrhythmia in 21 of the 35 patients had been unsuccessfully treated by digoxin (6), verapamil (5), ajmalin (4), propranolol (3), spartein (1), phenytoin (1), and lidocain (1) prior to the propafenone therapy. However, the arrhythmias could be abolished or reduced in 30 patients (85.7%) by Propafenone. In 5 patients with supraventricular tachycardia (2), junctional tachycardia (2), or ventricular extrasystole (1), propafenone therapy had no effect. In two other patients propafenone led to atrioventricular conduction disturbances and had to be discontinued. Propafenone is an effective well tolerated antiarrhythmic drug without major side effects in pediatric patients.     

Endogenous production of nitric oxide in endotoxemic piglets

We sought to assess the relation between endotoxin-induced pulmonary hypertension and the production of nitric oxide (NO) in neonatal animals. Adult animals respond to endotoxin by increasing exhaled NO and plasma NO metabolites. The response of neonatal animals has not previously been reported. We administered 20 microg/kg of Escherichia coli lipopolysaccharide (LPS) to 12- to 18-day-old and to 5- to 7-week-old piglets. Pulmonary vascular resistance increased significantly in both age groups. Exhaled NO in the 12- to 18-day-old animals and in the 5- to 7-week-old piglets did not increase significantly. A similarly treated group of adult rats did show a significant increase in exhaled NO (2.6 +/- 1.0 to 109.5 +/- 54.3 ppb; p = 0.028). Plasma NO metabolite measurements followed the same pattern of no increase in both porcine groups, and a large increase in the rat group. However, immunostaining of lungs from 12- to 18-day-old piglets did reveal an increase in inducible NO synthase. These results suggest that piglets demonstrate a limited ability to modulate LPS-induced pulmonary hypertension by elevations in exhaled NO. They also demonstrate the differential response to LPS between species.     

Ventricular dysrhythmias after congenital heart surgery: a canine model

To examine the possible mechanisms of ventricular dysrhythmias in the presence of right ventricular hypertension and following ventriculotomy, we instrumented 6-month-old puppies. There were four groups: 1) six animals served as controls (instrumentation only); 2) six animals underwent ventriculotomy only; 3) six animals underwent pulmonary artery banding with a pneumatic vessel occluder to produce right ventricular hypertension; 4) six animals had both ventriculotomy and right ventricular hypertension. Each week for 8 wk, 24-h electrocardiograms and electrophysiologic studies were performed with the animals awake and unsedated. We attempted to induce ventricular dysrhythmias with premature extrastimuli, rapid pacing, isoproterenol, and vagal stimulation. The following "chronic" data were obtained in week 8 (p value for overall analysis of variance; values are mean +/- SD): heart rate - 126 +/- 16 beats/min (no significant difference between groups; all animals); right ventricular systolic pressure: control 26 +/- 6 mm Hg, ventriculotomy 30 +/- 3, right ventricular hypertension 65 +/- 5, ventriculotomy and right ventricular hypertension 75 +/- 18 (p less than 0.001); right ventricular end diastolic: control 4 +/- 1 mm Hg, ventriculotomy 4 +/- 3, right ventricular hypertension 11 +/- 5, ventriculotomy and right ventricular hypertension 16 +/- 7 (p less than 0.001); QRS duration: control 22 +/- 5 ms, ventriculotomy 33 +/- 7, right ventricular hypertension 44 +/- 6, ventriculotomy and right ventricular hypertension 49 +/- 4 (p less than 0.01); right ventricular apex-base interval with ventricular pacing: control 20 +/- 3 ms, ventriculotomy 34 +/- 9, right ventricular hypertension 30 +/- 5, ventriculotomy and right ventricular hypertension 31 +/- 6 (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)     

Onset of puberty at eight years of age in girls determines a specific tempo of puberty but does not affect adult height

AIMS: To analyse the effect of early puberty (onset between 7.5 and 8.5 y) on pubertal growth and adult height in girls, and the implications of this effect for the age limit for normal onset of puberty. METHODS: Longitudinal study in Reus (Spain) of 32 girls with early puberty until they reached adult height. Data from these girls were compared with longitudinal data from girls (116) from the same population with normal onset at 10 (n = 37), 11 (n = 47), 12 (n = 19) and 13 (n = 13)y. We analysed height, target height, adult height, pubertal height increase, duration of pubertal growth, age at menarche and time to menarche. RESULTS: The adult height of girls with early puberty (160.9 +/- 5.4cm) was similar to that of girls with onset at later ages (p = not significant). In these girls, puberty lasted 5.4 +/- 0.7 y and the mean growth during puberty was 31.1 +/- 3.5 cm. As the age of onset of puberty increases, the duration of puberty and mean growth during puberty progressively decreased (p < 0.001). Girls with early puberty reached menarche at a mean age of 10.9 +/- 1.0 y, 3.2 +/- 0.9 y after onset of puberty, and this time span was greater than in the other groups. CONCLUSION: Girls with onset of puberty at 8 y show all the compensatory phenomena related to height at onset, pubertal duration and height increase during puberty. These phenomena cause their adult height to be similar to that of girls who begin puberty at the age of 10 to 13 y.     

A limited interval of delayed modest hypothermia for ischemic brain resuscitation is not beneficial in neonatal swine.

This investigation determined if a short interval of modest hypothermia (1 h) initiated 30 min after brain ischemia provided neuroprotection. The rationale for the time and duration of brain cooling reflects the likelihood that the implementation of neuroprotective strategies will occur at an interval shortly after ischemia, and that long-term maintenance of normothermia is a cornerstone of neonatal stabilization. Studies were performed in 22 ventilated neonatal mini-swine in a superconducting magnet to obtain 31P magnetic resonance spectra. After a control period all animals underwent 15 min of global brain ischemia and were maintained normothermic for the first 30 min post-ischemia. In one group of 11 swine normothermia was continued. In the other group of 11 swine, modest hypothermia was initiated at 30 min post-ischemia, continued for 1 h and followed by resumption of normothermia. Animals were subsequently weaned from ventiltor support, removed from the magnet, and underwent neurobehavioral and histologic assessment at 72 h post-ischemia. Both groups had similar severity of ischemia, as indicated by identical changes in arterial blood pressure and pH, alterations in brain beta-nucleotide triphosphate (% of control where control = 100%, 32 +/- 28 vs 27 +/- 26% for normothermic and hypothermic groups, respectively), and the extent of intraischemic brain acidosis (6.13 +/- 0.19 vs 6.14 +/- 0.14 for normothermic and hypothermic groups, respectively). In both groups the distribution of stages of encephalopathy were the same: 1 normal and 10 abnormal (4 mild, 2 moderate, and 4 severe) normothermic, and, 3 normal and 8 abnormal (4 mild, 2 moderate, and 2 severe) hypothermic animals. There was no difference in the extent of neuronal injury between groups. We conclude that a 1-h interval of modest hypothermia initiated at 30 min post-ischemia does not confer neuroprotection.     

每六周皮下注射促性腺激素释放激素类似物缓释剂干预女孩特发性中枢性性早熟

目的　观察延长促性腺激素释放激素类似物 (GnRHa)缓释剂注射间期对特发性中枢性性早熟女孩下丘脑 垂体 性腺轴抑制情况和临床症状改善方面的效果。方法　 4 6例特发性中枢性性早熟女孩随机分为两组 ,A组 :2 6例 ,年龄 (8 3± 1 4 )岁 (6 1～ 11 2 )岁 ,乳房开始发育年龄 (6 6±1 4 )岁 (2～ 8)岁 ,骨龄 (8 9± 1 5 )岁 (6 8～ 11 5 )岁 ;每 6周腹部皮下注射曲普瑞林 3 75mg ,平均剂量为 2 8± 0 6 (1 8～ 4 1) μg/ (kg·d) ;B组 :2 0例 ,年龄 (8 1± 1 3)岁 (5 1～ 10 3)岁 ,乳房开始发育年龄 (7 0± 1 2 )岁 (4～ 8)岁 ,骨龄 (8 9± 1 4 )岁 (6～ 11 5 )岁 ;每 4周肌肉注射曲普瑞林 3 75mg,平均剂量为 4 8± 1 1(3 2～ 7 4 ) μg / (kg·d)。两组均连续用药 1年以上。治疗过程中注意监测以下指标 :性发育情况、身高、体重、生长速率、血性激素的水平、骨龄等。结果　每 6周皮下注射曲普瑞林3 75mg的治疗方案与每 4周肌肉注射普瑞林 3 75mg的治疗方案均能使患儿的第二性征减退、停止发育 ,乳房发育明显受到抑制 ,乳腺回缩或乳腺组织变松软 ;卵巢体积缩小 ,直径大于 0 4cm的卵泡消失 ;促性腺激素分泌减少 ,性激素下降至青春前期水平 ;A、B两组的年生长速率 (cm/年 )分别由治疗前的 6 3±     

Umbilical cord separation in the normal newborn

During a 13-month period, 363 infants were followed up through the first six weeks to determine the effect of perinatal factors (birth weight, gestational age, type of delivery, and pregnancy and neonatal complications) on umbilical cord separation. Also, breast-feedings and umbilical cord care were studied. Except for cesarean section deliveries, study infants were similar to all infants (N = 1474) admitted to the same nursery during the study period. Cord separation occurred from days three to 45, with a mean of 13.9 days. Infants born by cesarean section were found to have an increased interval for cord separation when compared with infants born vaginally (mean +/- SD, 15.9 +/- 5.0 days vs 12.9 +/- 4.2 days). In this study, delays in separation of the umbilical cord beyond 3 weeks of age was not associated with an increased risk of infection.     

Granulocytic stem cell (CFUc) proliferation in experimental group B streptococcal sepsis

Adult rats infected with group B streptococci (GBS) develop neutrophilia and display a marked increase in granulocytic stem cells (CFUc). In contrast, infected neonatal rats develop a profound neutropenia and their CFUc do not increase. In order to better understand this phenomenon, we assessed the CFUc proliferative rate in control and infected adult and neonatal rats using the technique of [3H]-thymidine suicide. Beginning only 3 h after GBS inoculation, adult rats increased CFUc proliferative activity, as illustrated by an increase in thymidine suicide, from 38 +/- 2% cell kill in control animals to 70 +/- 2% when infected (mean + S.E., P less than 0.001). In contrast, the CFUc thymidine suicide rate did not increase in infected neonates. It was noted, however, that the baseline CFUc thymidine suicide rate in uninfected neonatal rats exceeded the rate in uninfected adult rats by 2-3-fold. The CFUc thymidine suicide rate was therefore determined in uninfected premature (74 +/- 1%), newborn (70 +/- 2%), 1-wk-old (70 +/- 1%), 6-wk-old (32 +/- 1%) and 6-month-old (37 +/- 3%) rats. These findings suggest that the proliferative rate of granulocytic stem cells is already maximal or near maximal in noninfected neonatal animals. In contrast to adults, the neonates' granulocyte production from stem cells can not significantly increase, even if bacterial infection is present.