Yasushi Nako

Ultrasonographic detection of very thin percutaneous central venous catheter in neonates.

To assess the ability of ultrasonography to detect the tip of a very thin (0.4 mm outer diameter) percutaneous central venous catheter (PCVC) in neonates, the PCVC tip location was assessed by ultrasonography (US) and compared to the location estimated by standard radiography for 57 PCVCs in 44 neonates. Of 57 occasions, the examiner could not find the PCVC tip in three cases (5%). In the remaining 54 instances, in 87% of cases, the PCVC tip position was consistent with the location implied by skeletal landmarks on standard radiographs. On 24 occasions we also assessed catheter tip dislodgement according to flexion and extension of the infants arm. US could detect 78% of cases of catheter tip dislodgement. The PCVC tip was sometimes visualized as a dot and parallel lines as well as mere parallel lines. In a large population of cases, US is a reliable method for detection of a thin PCVC tip. US provides precise information about the PCVC tip position in relation to vascular structure and contributes to safer positioning of the PCVC than traditional radiography alone.

Effects of bathing immediately after birth on early neonatal adaptation and morbidity: A prospective randomized comparative study

Objective : Because the risks and benefits of early bathing of newborn infants are not well established, we investigated the effects of bathing immediately after birth on rectal temperature, respiratory rate, heart rate, blood pressure, percutaneous arterial blood oxygen saturation (SpO2) and early neonatal morbidity.

Role of Serum Leptin in the Regulation of Weight Gain in Early Infancy

We investigated the changes in the serum leptin concentration from birth to 30 days of age in order to determine the effects of leptin in early infancy. Twenty-seven Japanese term infants (12 boys and 15 girls) were examined. The serum leptin concentration at 3–6 days of age was significantly lower than that in cord blood (p < 0.0001) and was significantly higher at 30 days than at 3–6 days (p < 0.0001). The serum leptin concentration did not differ with gender or nutrition. The body weight gain and the magnitude of leptin rise that occurred between 3–6 and 30 days of age showed a significant positive correlation (r = 0.79; p < 0.0001). These changes in leptin levels suggest that leptin plays an important role in the regulation of weight gain in early infancy.

Risk of hypervitaminosis D from prolonged feeding of high vitamin D premature infant formula

Abstract Background : Most premature infant formulas marketed in Japan have high vitamin D content. Potential for vitamin D intoxication was assessed in premature infants with prolonged feeding of such a premature formula vitamin D content, 2700 IU/L.

Analysis of Gastrointestinal Sounds in Infants With Pyloric Stenosis Before and After Pyloromyotomy

Background. Although recent advances in computer technology enable us to analyze gastrointestinal sounds data objectively with ease, this clinical application has been investigated in only a few disorders. To investigate one potential role of this approach in pediatric practice, we recorded and analyzed gastrointestinal sounds in infants with hypertrophic pyloric stenosis (HPS), a motility-related disorder that is common in children. Methods. In 15 infants with pyloric stenosis, gastrointestinal sounds were collected with a microphone placed 3 cm below the umbilicus for 60 minutes before pyloromyotomy and at 9 to 12 hours, 20 to 24 hours, 40 to 48 hours, and 112 to 120 hours after the operation. Data were entered into a computer to sum the amplitude of sound signals as a sound index (SI; mV per minute). In 12 infants, gastric emptying was measured immediately before each sound recording, using a marker dilution-double sampling method. Results. Before surgery, the mean SI was 4.6 ± 1.0 mV per minute, significantly less than in healthy controls (31.7 ± 8.4 mV per minute). The SI remained in a similar range until 12 hours after operation, after which it began increasing to reach the normal range by 48 hours after operation (30.0 ± 9.4 mV per minute). Gastric emptying, also low in HPS before pyloromyotomy, increased by 4 to 5 times after surgery. There was a significant positive correlation between SI and gastric emptying. The incidence of postoperative symptoms (such as vomiting) were correlated significantly with SI at 24 hours after surgery. Conclusion. This study found decreased gastrointestinal sounds to be among physical findings suggestive of HPS and a useful indicator of gastric emptying and bowel motility after pyloromyotomy. Computer-assisted analysis of gastrointestinal sounds might be helpful in clinical practice for pediatric patients with some gastrointestinal disorders.

Transcutaneous oxygen tension measurements during methacholine challenge of prematurity in infants with chronic lung disease.

Chronic lung disease (CLD) of prematurity may be caused by a number of insults during mechanical ventilation, including barotrauma and hyperoxia. To evaluate bronchial hyperresponsiveness (BHR) in infants with CLD of prematurity, we measured changes in transcutaneous oxygen tensions (tcPO2) during methacholine inhalation challenge. Twelve infants with CLD and 22 age‐matched children without respiratory diseases were enrolled in this study (ages—5 to 36 months; mean age—16.2 months). Serial doses of methacholine were doubled until a 10% decrease in tcPO2 from baseline was reached. The cumulative dose of methacholine inhaled by the time tcPO2 had been reached (Dmin‐PO2) was considered to represent the dose at which reactivity to methacholine (RO2meth) had occurred.

The effect of aerosolized furosemide in infants with chronic lung disease

To investigate whether aerosolized furosemide would improve pulmonary function in premature infants with chronic lung disease, we enrolled eight preterm ventilator‐dependent infants in a cross‐over, double‐blind. placebo‐controlled trial. Either aerosolized furosemide (2mg/kg) or placebo (0.9% saline) was administered, and serial pulmonary function tests were performed before and at 1 and 2h after each inhalation. After furosemide inhalation, static respiratory compliance increased significantly by 24.3% and 23.2% as percentage change from the baseline value at 1 and 2h (p= 0.014 and 0.022, respectively). Also, tidal volume increased significantly by 33.8% and 28.7% at 1 and 2h, respectively (p= 0.004 and 0.009). In contrast, no changes were observed in them after placebo inhalation. Total respiratory resistance was unchanged after both furosemide and placebo inhalation. There were no differences in urine volume in two groups. These data suggested that aerosolized furosemide improved pulmonary function in infants with chronic lung disease without excessive diuresis.

Plasma thrombomodulin level in newborn infants with and without perinatal asphyxia

To determine whether vascular endothelial damage occurs in neonates with asphyxia, we examined the plasma thrombomodulin level at birth in infants with and without asphyxia. The plasma thrombomodulin concentration in 11 asphyxiated infants was significantly elevated compared with that in 48 infants without asphyxia (38.1 vs 27.0 μg/l, p < 0.0001). The plasma thrombomodulin‐to‐serum creatinine ratio was also significantly elevated (0.62 vs 0.48 μg/μmol, p= 0.0005). The plasma thrombomodulin concentration and the plasma thrombomodulin‐to‐serum creatinine ratio in infants without asphyxia did not differ between the two types of delivery: normal vaginal delivery and elective caesarean section. Stepwise regression analysis showed the serum D‐dimer concentration, plasma pH and serum creatinine concentration were significant independent variables for plasma thrombomodulin concentration, whereas base deficit, platelet count, fibrinogen concentrations and antithrombin III activity were not. Our data suggest that vascular endothelial damage might occur in asphyxiated infants.

Ultrasonographic assessment of intragastric volume in neonates: Factors affecting the relationship between intragastric volume and antral cross-sectional area

Measuring antral crosssectional area by ultrasonography can be an ideal way to evaluate intragastric milk volume in infants. Technical details, however, remain to be established before its clinical application. We investigated the effects of posture and ultrasonographic plane on the correlation between milk volume and antral cross-sectional area. After gastric aspiration through a nasogastric tube, healthy newborns were fed 0, 10, 20, and 40 ml of milk cumulatively, and antral cross-sectional area was measured in either upright, sitting, or right lateral position. To determine the best sonographic plane, subjects were put in the right lateral position and antral cross-sectional area was measured in the plane of the aorta and either the superior mesenteric artery, the superior mesenteric vein, the midline of the abdominal surface, 1 cm right of midline, or 2 cm right of midline. The results showed that antral cross-sectional area reflects intragastric milk volume most accurately, with minimal gas interference when measured in the right lateral position. The area correlates well with milk volume in the plane of the aorta and either the superior mesenteric artery, the superior mesenteric vein, or the midline. Next, we studied the effect of intragastric gas on the antral cross-sectional area in subjects who were given 40 ml of milk followed by an injection of air. More than 20 ml of intragastric gas increases antral cross-sectional area significantly. Ultrasonographic evaluation of intragastric volume requires attention to the above factors.

Cellular adhesion is required for effector functions of human eosinophils via G-protein coupled receptors

BACKGROUND Eosinophils play an important role in the pathogenesis of allergic diseases. Chemoattractants, including platelet-activating factor (PAF) and complement component 5a (C5a), induce eosinophil infiltration and promote eosinophil effector functions. OBJECTIVE To compare eosinophil degranulation and superoxide anion (O2-) generation induced by various chemoattractants, and to elucidate the role of cellular adhesion on these effector functions. METHODS Human eosinophils were stimulated with PAF, C5a, eotaxin, or leukotriene B4 (LTB4). O2- generation was assayed by a chemiluminescence method using a Cypridina luciferin analog as the amplifier. Degranulation and adhesion were measured by quantitating eosinophil protein X by radioimmunoassay. Expression of CD11b on eosinophils was measured by flow cytometry. RESULTS PAF and C5a induced significant degranulation and O2- generation from eosinophils. In contrast, the potency of eotaxin or LTB4 for these functions was much less. PAF and C5a also significantly enhanced eosinophil adhesion, whereas eotaxin and LTB4 did not. CD11b expression on eosinophils was enhanced by all four stimulants, and the order of potency to induce CD11b expression was C5a > PAF > eotaxin > LTB4. CONCLUSIONS The potency of PAF and C5a for inducing effector function in eosinophils was greater than that of eotaxin or LTB4. The magnitude of the effector function was consistent with the degree of eosinophil adherence induced by each stimulant. These results suggest that effector functions of eosinophils which are mediated through G-protein coupled receptors are dependent on cellular adhesion.