Efficacy of parent-child interaction therapy for children born premature

BACKGROUND

Premature children are known to be at a high risk of developing behavioral problems. This study examined the effectiveness of parent-child interaction therapy (PCIT) in reducing behavioral problems in young children born premature.

METHODS

The study included 18 child-parent pairs with children born at less than 35 weeks of gestation (range: 23-34 weeks, median: 31.0 weeks) and aged 27-52 months (median: 38.0 months). They were assigned to either the PCIT group (n = 7) or the non-PCIT group (n = 11) based on maternal desire for treatment. The study was designed to examine the effects of PCIT. Specifically, the Eyberg Child Behavior Inventory (ECBI) intensity score, ECBI problem score, and Parenting Stress Index Short Form (PSI-SF) scores were compared before treatment and after 6 months.

RESULTS

In the PCIT group, the mean ECBI intensity score was 135.7 (SD = 13.5; T-score = 64) at baseline and 90.1 (SD = 15.5; T-score = 46) at post-assessment, the mean ECBI problem score was 9.8 (SD = 1.9; T-score = 54) at baseline and 4.4 (SD = 3.1; T-score = 44) at post-assessment, the mean PSI-SF total score was 60.1 (SD = 4.8; 95%tile) at baseline and 49.6 (SD = 5.6; 85%tile) at post-assessment, showing a significant improvement (ECBI intensity scores: p < 0.001, d = 2.03; ECBI problem scores: p < 0.001, d = 1.94; PSI-SF total scores: p = 0.004, d = 0.86). On the other hand, none of the scores showed significant change in the non-PCIT group.

CONCLUSIONS

The PCIT can be considered as a potential treatment option for behavioral problems in young children born premature.

Neonatal respiratory support related to lung function abnormalities in school-age children with bronchopulmonary dysplasia

OBJECTIVE

To elucidate the relationship between abnormal lung function (LF) at school age and neonatal respiratory support in very low birth weight children with bronchopulmonary dysplasia (BPD).

STUDY DESIGN

We retrospectively examined 78 BPD children whose LF was evaluated at 8-9 years. LF abnormalities were defined by reduced values of spirometric parameters. Adjusted odds ratios (aORs) for abnormal LF by the type and postmenstrual age (PMA) of respiratory support were calculated using logistic regression analysis after controlling perinatal factors.

RESULTS

Overall, 24 (31%) patients had LF abnormalities. Antenatal steroid use was associated with a decreased risk of abnormal LF [aOR, 0.31; 95% CI, 0.09-0.92]. Requiring positive-pressure support at 37 weeks' PMA correlated with abnormal LF [aOR, 4.58; 95% CI, 1.15-21.90]; whereas only low-flow oxygen at any PMA did not.

CONCLUSION

Requiring positive-pressure support at 37 weeks' PMA could be an indicator of abnormal LF at school age.

Disseminated intravascular coagulation complicated by amniotic band syndrome associated with deceased fetal umbilical cord following fetoscopic laser surgery

Fetoscopic laser surgery occasionally causes amniotic band syndrome, in which the disrupted amniotic membrane constricts fetal body parts, leading to functional or morphological loss. We report a case of fetal distress at 31 weeks of gestation in the larger surviving twin after fetoscopic laser surgery for selective intrauterine growth restriction, necessitating emergent cesarean section. Physical examination of the infant showed constriction rings caused by a disrupted amniotic membrane on the digits, and the distal part of the right index finger was necrotic because of tight strangulation by an amniotic band with the umbilical cord of the deceased smaller twin. Laboratory data showed severe coagulopathy, and the infant was diagnosed with disseminated intravascular coagulation (DIC). Immediate treatment improved his condition. DIC may have been associated with the necrotic finger, which was strangulated by the umbilical cord of the deceased fetus, because neither maternal coagulopathy nor an underlying neonatal disorder was detected.

Synergic interaction between ritodrine and magnesium sulfate on the occurrence of critical neonatal hyperkalemia: A Japanese nationwide retrospective cohort study

Our aim was to evaluate the association between ritodrine and magnesium sulfate (MgSO4) and the occurrence of neonatal hyperkalemia or hypoglycemia among late preterm infants in a retrospective cohort study. We used a nationwide obstetrical database from 2014. A total of 4,622 live preterm infants born at 32-36 gestational weeks participated. Fourteen risk factors based on both clinical relevance and univariate analysis were adjusted in multivariable logistic regression analyses. Neonatal hyperkalemia and hypoglycemia occurred in 7.6% (284/3,732) and 32.4% (1,458/4,501), respectively. Occurrence of hyperkalemia was associated with concomitant usage of ritodrine and MgSO4 compared with no usage (adjusted odds ratio [aOR] 1.53, 95% confidence interval [CI] 1.09-2.15). Occurrence of hypoglycemia was associated with ritodrine alone (aOR 2.58 [CI 2.21-3.01]) and with concomitant usage of ritodrine and MgSO4 (aOR 2.59 [CI 2.13-3.15]), compared with no usage, and was associated with long-term usage (≥ 48 hours) of ritodrine and cessation directly before delivery. In conclusion, in late preterm infants, usage of ritodrine together with MgSO4 was associated with occurrence of critical neonatal hyperkalemia, and long-term usage of ritodrine and cessation directly before delivery were associated with neonatal hypoglycemia.

Takotsubo syndrome occurring concomitantly with pre-eclampsia: A case report

Takotsubo syndrome (TTS) patients show transient ventricular dysfunction without coronary artery stenosis. We report a pregnant woman with TTS occurring concomitantly with severe pre-eclampsia (PE). A primiparous woman complained of dyspnea at 35 weeks of gestation. She showed severe PE, and cardiac ultrasound identified akinesis of the anterior lower wall. On the same day, emergent cesarean section was performed due to a nonreassuring fetus status, yielding a male infant with an umbilical artery pH of 6.851. Unfortunately, the neonate died of multiple organ failure. Following the delivery, her cardiac function markedly improved, and coronary angiography showed no coronary artery stenosis. Considering the clinical findings, we diagnosed the patient with TTS. Regarding antenatally occurring TTS, only six patients have been reported including the present one. Of the six patients, three had severe PE. Although previous reports on pregnancy-associated TTS described good maternal outcomes, antenatally occurring TTS complicated by severe PE may become critical for fetuses.

Vaginal Ureaplasma species increase chorioamnionitis in very preterm infants with preterm premature rupture of the membranes at < 28 weeks of gestation

Our aim was to investigate the association between vaginal Ureaplasma species (spp.) and the subsequent occurrence of chorioamnionitis (CAM), perinatal death, neonatal morbidity, and long-term neurodevelopmental impairments (NDIs) at 3 years of age. We analyzed 55 pregnant women with singleton pregnancy who had preterm premature rupture of the membranes (pPROM) at < 28⁺⁰ weeks of gestation, and delivered between 22⁺⁰ and 31⁺⁶ weeks at our tertiary hospital in 2007-2016. NDIs were defined as either cerebral palsy or developmental delay evaluated at 1.5 and/or 3 years old. The presence of Ureaplasma spp. and Mycoplasma hominis were evaluated using urea-arginine broth and Mycoplasma PPLO Agar. The presence of Ureaplasma spp. in the vagina was positive in 41%. Vaginal Ureaplasma spp. was a significant risk factor for CAM; however, it was not significantly associated with the occurrence of perinatal death, pulmonary hypoplasia, respiratory distress syndrome, transient tachypnea of the newborn, intraventricular hemorrhage, periventricular leukomalacia, bronchopulmonary dysplasia defined as oxygen required and occasional ventilatory assistance required at week 36 as modified (BPD₃₆), or NDIs. The crude odds ratio (95% confidence interval) of Ureaplasma spp. for the occurrence of CAM was 9.5 (1.10-82) (p = 0.041). In very preterm birth infants with pPROM, CAM, BPD₃₆, and NDIs occurred in 78, 60, and 36%, respectively. Vaginal Ureaplasma spp. was a significant risk factor for CAM in very preterm birth infants with pPROM. The incidences of BPD₃₆ and NDIs in such infants were very high, nearing 3/5 and 1/3, respectively.

Neonatal factors related to center variation in the incidence of late-onset circulatory collapse in extremely preterm infants

BACKGROUND

Although late-onset circulatory collapse (LCC) is widely recognized in Japan, its etiology and the reason for center variation in its incidence remain unclear. This study's objectives were to identify the perinatal and neonatal factors related to LCC and to estimate the factors related to the center variation in the incidence of LCC.

METHODS

Extremely preterm infants born between 2008 and 2012 who were registered in the database of the Neonatal Research Network, Japan were retrospectively analyzed. LCC was defined as a clinical diagnosis of LCC and the administration of steroids. We first identified the factors that were significantly related to LCC. We then examined the cause of the center variation in the incidence of LCC, using the standardized incidence ratios (SIRs) of LCC and individual factors.

RESULTS

The factors significantly associated with LCC included low gestational age (odds ratio [OR]: 1.13), small for date (OR: 1.43), male sex (OR: 1.26), antenatal steroid use (OR: 1.19), respiratory distress syndrome (OR: 1.25), chronic lung disease at 36 weeks (OR: 1.16), periventricular leukomalacia (PVL) (OR: 2.57), necrotizing enterocolitis (OR: 0.59), retinopathy of prematurity (ROP) (OR: 1.73), high-frequency oscillating ventilation (HFOV) use (OR: 1.31), parenteral nutrition (OR: 1.38), and red blood cell (RBC) transfusion (OR: 1.94). The SIR of LCC ranged from 0.05 to 2.94, and was positively correlated with SIRs of PVL, ROP, HFOV use and RBC transfusion.

CONCLUSION

PVL, ROP, HFOV use and RBC transfusion were found to be correlated with the center variation in the incidence of LCC.

Pelizaeus-Merzbacher disease can be a differential diagnosis in males presenting with severe neonatal respiratory distress and hypotonia

Pelizaeus-Merzbacher disease (PMD; MIM #312080) is a rare X-linked recessive disorder. A male neonate presented with severe respiratory distress that required tracheostomy. After the appearance of nystagmus, PMD was suspected as a diagnosis for the patient, and a missense mutation, p.Phe51Val, was identified in PLP1, the gene responsible for PMD. PMD can be a differential diagnosis in a male neonate presenting severe respiratory distress.

Hyperinsulinemic hypoglycemia in Beckwith-Wiedemann, Sotos, and Kabuki syndromes: A nationwide survey in Japan

Beckwith-Wiedemann syndrome (BWS) is a congenital overgrowth syndrome that is occasionally associated with hyperinsulinemic hypoglycemia (HH) in the neonatal period. Sotos syndrome (SS) and Kabuki syndrome (KS) are other malformation syndromes that may be complicated with HH, however, the detailed clinical characteristics of HH accompanied with these syndromes remain unclear. We herein conducted a nationwide questionnaire survey in Japan. We sent a primary questionnaire concerning the clinical experience for these syndromes to 347 perinatal care institutions. As a result, 222 departments or hospitals returned the questionnaires and the total numbers of BWS, SS, and KS patients were 113, 88, and 51, respectively. We sent a secondary questionnaire to 31 institutions where patients with these syndromes presented with HH during infancy. The secondary questionnaires were returned from the institutions and the numbers of patients were 16 for BWS, 9 for SS, and 3 for KS, respectively. Then, we compared the clinical characteristics of infants suffering from transient HH with and without these dysmorphic syndromes. As a result, BWS, SS, and KS patients showed significantly larger body size, lower Apgar scores, higher insulin levels at HH, and shorter durations of HH than non-dysmorphic infants with transient HH. We propose that a careful observation for the signs of HH, even if not specific to the syndromes, is important for the diagnosis of patients with BWS, SS, and KS in the postnatal period. © 2016 Wiley Periodicals, Inc.

Cytokine profile in two siblings with neonatal lupus erythematosus

We studied the cytokine profile of two siblings with neonatal lupus erythematosus (NLE) born to a mother positive for serum anti-Ro and -La antibodies, who did not receive any medication during the two pregnancies. The first sibling was found to have complete atrioventricular block in utero and became severely ill after birth. He fulfilled the diagnostic criteria for hemophagocytic lymphohistiocytosis on day 2. The second sibling did not have any fetal symptoms. He was generally stable after birth, but with typical skin rash. Laboratory data suggested that they both had hypercytokinemia during the neonatal period, requiring corticosteroid treatment. Interleukin (IL)-6, interferon-γ, IL-8 and monocyte chemotactic protein-1 were elevated in both cases, while IL-12, IL-13 and IL-17 were elevated only in the second sibling. Comparison of the cytokine profiles suggests the potential roles of different cytokines in the onset and clinical manifestations of NLE.

Gut hormones of preterm infants with abdominal symptoms and hypothyroxinemia

BACKGROUND

The pathogenesis of abdominal symptoms in premature infants with hypothyroxinemia is not understood; therefore, we investigated changes in gut hormones before and after levothyroxine sodium (T4-Na) supplementation in preterm infants with abdominal symptoms and hypothyroxinemia.

METHODS

In eight preterm study subjects and 14 gestational age-matched controls, fasting serum concentration of leptin, glucose-dependent insulinotropic polypeptide (GIP), glucagon-like peptide-1 (GLP-1), peptide YY (PYY), pancreatic polypeptide, insulin, amylin and ghrelin was measured using a bead array system.

RESULTS

Serum GLP-1, GIP and PYY in the subjects before T4-Na supplementation were lower than in controls at age 2 weeks. After improvement of abdominal symptoms and free thyroxine, serum levels of the three gut hormones in the subjects were increased and were not different from those in the control patients.

CONCLUSIONS

In preterm infants with abdominal symptoms, serum GLP-1, GIP and PYY might be related to thyroid function.

Constitutively high-level expression of TGFβ isoforms in cord blood and its relationship to perinatal findings

BACKGROUND

The clinical significance of TGFβ isoforms in cord blood is not well understood.

METHODS

We obtained cord blood samples from 37 term infants and 85 preterm infants who were born in several clinical settings. The serum levels of 3 TGFβ isoforms and of the other 17 cytokines in cord blood were investigated using cytometric bead array technology.

RESULTS

Very high levels of TGFβ1 and TGFβ2 isoforms compared to the level of other cytokines were found; mean levels were 44,180 and 1871pg/mL, respectively. The levels of all 3 isoforms of TGFβ were significantly correlated with birth weight, and the levels of TGFβ1 and TGFβ3 were correlated with gestational age. The levels of TGFβ1 and β2 isoforms were strongly correlated with each other, but not with levels of other cytokines. The levels of TGFβ1 and TGFβ2 were significantly higher in male infants and significantly lower in infants with fetal growth restriction. The prevalence of chronic lung disease was related to a low level of TGFβ1, and that of patent ductus arteriosus was related to a high level of TGFβ1 in preterm infants.

CONCLUSIONS

TGFβ1 and TGFβ2 appeared to play a significant role in physiological and pathological conditions in the fetus. TGFβ isoform levels appear to be regulated independently of those of other cytokines and do not appear to be influenced by inflammation in the fetal period. The role of TGFβ3 in cord blood and the postnatal chronological changes of the TGFβ isoforms should be investigated in the future.

Gut hormone profiles in preterm and term infants during the first 2 months of life

AIM

To investigate changes of gut hormones in term and preterm infants in the first 2 months after birth, as the role and relationships of gut hormones in premature infants has not been well elucidated.

METHODS

In 29 preterm and five term infants, fasting serum concentrations of leptin, glucose-dependent insulinotropic polypeptide (GIP), glucagon-like peptide-1 (GLP-1), peptide YY (PYY), pancreatic polypeptide, insulin, amylin, and ghrelin were measured using a bead array system.

RESULTS

Serum leptin concentration soon after birth showed a positive correlation with gestational week in all infants (r=0.623, p<0.01). Serum leptin level rapidly decreased in all infants. In preterm infants, serum GLP-1 levels at birth showed negative correlations with gestational week (r=-0.447, p=0.02). Serum GIP, GLP-1, and PYY levels increased after birth and were persistently high until 10 weeks of life.

CONCLUSION

Serum concentrations of different gut hormones changed postnatally in their specific ways in preterm infants.

Williams-Beuren syndrome with brain malformation and hypertrophic cardiomyopathy

Williams-Beuren syndrome (WBS) is a multisystemic genetic disorder caused by a contiguous gene deletion at 7q11.23. We report a severely affected WBS patient with cerebral and cerebellar dysplasia as well as hypertrophic cardiomyopathy. Microarray comparative genomic hybridization (aCGH) detected a deletion on 7q11.23 expanding from RP11-614D7 to RP11-137E8, which is a typical deletion in WBS. To the best of our knowledge, this is the first case report of a WBS patient with severe congenital central nervous system anomaly and progressive hypertrophic cardiomyopathy. The relationship between the genes deleted in WBS and a CNS anomaly plus hypertrophic cardiomyopathy requires further analysis.

Ash1l methylates Lys36 of histone H3 independently of transcriptional elongation to counteract polycomb silencing

Molecular mechanisms for the establishment of transcriptional memory are poorly understood. 5,6-dichloro-1-D-ribofuranosyl-benzimidazole (DRB) is a P-TEFb kinase inhibitor that artificially induces the poised RNA polymerase II (RNAPII), thereby manifesting intermediate steps for the establishment of transcriptional activation. Here, using genetics and DRB, we show that mammalian Absent, small, or homeotic discs 1-like (Ash1l), a member of the trithorax group proteins, methylates Lys36 of histone H3 to promote the establishment of Hox gene expression by counteracting Polycomb silencing. Importantly, we found that Ash1l-dependent Lys36 di-, tri-methylation of histone H3 in a coding region and exclusion of Polycomb group proteins occur independently of transcriptional elongation in embryonic stem (ES) cells, although both were previously thought to be consequences of transcription. Genome-wide analyses of histone H3 Lys36 methylation under DRB treatment have suggested that binding of the retinoic acid receptor (RAR) to a certain genomic region promotes trimethylation in the RAR-associated gene independent of its ongoing transcription. Moreover, DRB treatment unveils a parallel response between Lys36 methylation of histone H3 and occupancy of either Tip60 or Mof in a region-dependent manner. We also found that Brg1 is another key player involved in the response. Our results uncover a novel regulatory cascade orchestrated by Ash1l with RAR and provide insights into mechanisms underlying the establishment of the transcriptional activation that counteracts Polycomb silencing.

Do neonates conceived after assisted reproductive technology require neonatal surgery more frequently? A 5-year single-center experience

AIM

Assisted reproductive technology (ART) has increased the incidences of multiple gestations and low birth weights, which frequently warrant pediatric surgery. ART may have also increased the rate of birth defects. In this study, we aimed to determine whether infants conceived after ART required neonatal surgery more frequently compared with naturally conceived infants.

MATERIAL AND METHODS

Our study population comprised 1891 infants (160 ART (+) and 1731 ART (-)) who were admitted to our neonatal intensive care unit during a 5-year period (January 2006-December 2010); of these, 198 infants (9 ART (+) and 189 ART (-)), with diseases requiring surgery, were referred to pediatric surgeons (consultation cases). We examined the following: (i) factors potentially increasing the requirement for surgery; (ii) frequency of birth defects; and (iii) maternal factors that may increase the need for surgery.

RESULTS

A significantly higher incidence of multiple gestation and low birth weight was observed in the ART (+) group than the ART (-) group. However, ART did not yield a higher rate of surgery and birth defects: overall, the rate of surgery was 4% (7/160) in the ART (+) group and 8% (143/1731) in the ART (-) group. Of 198 consultation cases, the percentage of infants actually requiring surgery was approximately the same in the ART (+) group (7/9 [78%]) and the ART (-) group (143/189 [76%]).

CONCLUSION

Infants conceived after ART comprised a small proportion of neonatal surgery cases, and did not require surgery more frequently.

Selectively high level of serum interleukin 5 in a newborn infant with cow's milk allergy

Cow's milk allergy (CMA) in the neonatal period is thought to include several clinical conditions, yet the pathophysiology remains unclear. We report here the case of a term newborn infant who showed hematochezia 36 hours after the first feeding with cow's milk formula. His serum immunoglobulin E levels were not elevated, although eosinophils were detected in the stool. Elimination of cow's milk formula resolved the symptoms, and from the clinical course and laboratory data the infant was diagnosed with CMA. The serum interleukin 5 (IL-5) (125 pg/mL) level in this patient was selectively elevated. However, serum levels of other T-helper 2 (Th2) cytokines (including IL-4 and IL-13), Th1 cytokines (including interferon γ), and proinflammatory cytokines (including tumor necrosis factor α) were not elevated. These findings suggest that, for this patient, IL-5 and eosinophils might have played a role in the development of neonatal CMA. Although this finding is reported from only 1 case, it highlights the need for serum IL-5 to be determined in more neonatal patients with CMA to further clarify the pathophysiology of this condition in the neonatal period.

Association of development of chronic lung disease of newborns with neonatal colonization of Ureaplasma and cord blood interleukin-8 level

BACKGROUND

The aim of the present study was to investigate the association of chronic lung disease (CLD), neonatal Ureaplasma colonization, and interleukin-8 (IL-8) level of cord blood in preterm infants.

METHODS

In 77 infants of <32 weeks gestation, the relationship between IL-8 level of cord blood, neonatal colonization of Ureaplasma, histological chorioamnionitis (CAM), and development of CLD was studied.

RESULTS

Five infants died and 29 infants developed CLD. The CLD group had significantly lower gestation (mean ± SD: 26.6 ± 1.8 weeks) compared with the infants without CLD (28.9 ± 1.9 weeks, P < 0.0001). Logistic analysis showed that the development of CLD was associated with gestational age (odds ratio [OR], 0.5; 95% confidence interval (CI): 0.4-0.8) and Ureaplasma colonization (OR, 4.1; 95%CI: 1.2-14.4). Ureaplasma colonization was also associated with CAM (OR, 6.5; 95%CI: 1.8-23.5), absence of respiratory distress syndrome (OR, 6.2; 95%CI: 1.3-30.5), and development of CLD (OR, 4.0; 95%CI: 1.1-15.3). Elevated cord blood IL-8 ≥100 pg/mL was associated with female sex and the isolation of microorganisms (OR, 49.4; 95%CI: 4.6-525).

CONCLUSION

The development of CLD defined by oxygen requirement at 36 weeks was associated with neonatal Ureaplasma colonization but not with IL-8 level of cord blood. Elevated cord blood IL-8 was associated with neonatal microorganisms isolation.

Selectively high levels of serum interleukin 17 in a newborn infant with progressive severe cholestasis

We present here the unusual case of a male newborn infant who showed progressive severe cholestasis. The infant's gestational age was 37 weeks, and his birth weight was 2134 g. His serum level of direct bilirubin gradually increased from the 6th day of life and reached 257.5 micromol/L on the 22nd day of life. We could not find any cause for his cholestasis, but his serum level of ferritin was extremely elevated at 9211.0 ng/mL. Because we felt that his clinical condition might be related to hypercytokinemia caused by an immunologic reaction, steroid pulse therapy and cyclosporine were administered. His condition improved, and his direct bilirubin and ferritin levels declined. From the investigation of his cytokine profile, we found a preferentially elevated level of serum interleukin 17 (IL-17) (96.1 pg/mL) and high level of chemokines IL-8 and macrophage inflammatory protein 1beta. The IL-17 level gradually decreased to 7.5 pg/mL by the 124th day of life. The infant was successfully discharged from the children's hospital but later developed epilepsy at 11 months and asthma at 1 year, 2 months of age. Although we have not yet reached a definitive diagnosis, this case may be the first to show a relationship between cholestasis and an elevated serum IL-17 level in the neonatal period.

Prolonged maternal magnesium administration and bone metabolism in neonates

BACKGROUND

Magnesium sulfate (MgSO(4)) has been used as a tocolytic agent in cases of refractory preterm labor. Prolonged maternal administration of MgSO(4) may induce bone demineralization in the neonate. However, the effects of MgSO(4) on serum biochemistry related to bone metabolism in neonates remain unclear.

AIM

To assess the effects of prolonged maternal administration of MgSO(4) on fetuses and neonates.

STUDY DESIGN

This retrospective case-control study examined 167 neonates. Cases comprised 58 neonates whose mothers had received intravenous MgSO(4) administration for >5 days. Neonatal serum levels of magnesium (Mg), calcium (Ca), phosphorus (P) and alkaline phosphatase (ALP) were reviewed. We also investigated whether subject neonates showed appearance of osteopenia at the metaphyseal lines on radiography at birth.

RESULTS

Mean serum Mg and P levels were significantly higher, and Ca levels were significantly lower, in cases than in controls at birth. Mean serum ALP level was 1188.5IU/l in cases, significantly higher than that in controls at birth. Bone abnormalities were noted on radiography in 2 subjects. By 3 weeks old, serum ALP levels did not differ significantly between cases and controls. Logistic regression analysis revealed maternal administration of MgSO(4) and multiple pregnancies were significantly related to serum ALP level in neonates at birth.

CONCLUSION

Prolonged maternal administration of MgSO(4) significantly affects neonatal serum biochemistry related to bone metabolism. Potential long-term adverse effects on neonates and how Mg affects fetal bone metabolism in utero need to be investigated in future studies.

Hypothyroxinemia and effectiveness of thyroxin supplementation in very low birth weight infants with abdominal distension and poor weight gain

BACKGROUND

Very low birth weight (VLBW) infants sometimes develop abdominal distension and poor weight gain. The influence of thyroid function on these symptoms in VLBW infants has not been reported.

METHODS

In a retrospective study, 18 VLBW infants whose abdominal distension and poor weight gain did not improve with standard treatment were enrolled as subjects. Serum levels of free thyroxin (fT(4)) and thyroid stimulating hormone (TSH) were measured. Subjects with serum fT(4) levels less than 1.3 ng/dl received thyroxin supplementation. Another 18 VLBW infants were recruited as age- and weight-matched controls. We compared degree of intestinal dilation on X-ray, weight gain, and quantity of milk tolerated before and after starting thyroxin supplementation in the subjects and the controls.

RESULTS

All subjects had serum fT(4) levels less than 1.3 ng/dl (mean, 0.72 ng/dl). TSH values varied widely and were less than 8 microU/ml in 12 subjects. Therefore, all subjects received thyroxin supplementation; after starting this, mean serum fT(4) level increased significantly to 1.31 ng/dl. In parallel with fT(4) increase, intestinal dilation improved in 16 of 18 subjects (mean grade of dilation decreased from 2.8 to 1.6). Weight gain and quantity of tolerated milk were significantly increased with thyroxin supplementation in all and 17 of the 18 subjects, respectively.

CONCLUSIONS

Thyroxin supplementation was effective in improving abdominal symptoms in VLBW infants whose serum fT(4) level was less than 1.3 ng/dl.

Integrated backscatter of the brain of preterm infants

We measured integrated backscatter (IBS) in the brain of preterm infants using acoustic ultrasound. The study group consisted of 25 preterm infants (gestational age, 32.4+/-2.5 weeks; birth weight, 1488+/-422 g). In parasagittal scans through the posterior horn of the lateral ventricle, regions of interest (ROI) were positioned in the cerebral white matter near the posterior horn (P), anterior horn (A) of the lateral ventricle, and the thalamus (T). IBS of the ROI was measured and IBS of P minus T (P-T) and IBS of A minus T (A-T) were calculated. A-T was greater than P-T. A-T and P-T decreased with increasing gestational age and birth weight. These changes may represent maturation of the cerebrum. A-T or P-T may be useful parameters of cerebral tissue characterization.

Analysis of the intensity of radio-frequency signals in intracranial ultrasonography of preterm infants

PURPOSE

The purpose of this study was to evaluate the usefulness of analysis of the intensity of radio-frequency (RF) signals in intracranial ultrasonography of preterm infants.

METHODS

Twenty neonatal infants admitted to the neonatal intensive care unit of our hospital were included in this study. Their gestational age was 33-35 weeks. The studies were performed with a System 5 ultrasound system with 3.0-and 5.0-MHz transducers. The transducer was placed on the anterior fontanel to obtain images. Regions of interest were determined based on B-mode images and were positioned at the thalamus, caudate nucleus, cerebral white matter, cerebellum, brain stem, and lateral ventricle. The software used for analysis of the RF signals was EchoMAT (Vingmed Ultrasound).

RESULTS

The RF signals of the ventricle and the choroid plexus showed the lowest and the highest intensities, respectively. The intensities of the brain stem and vermis signals were the same, and were higher than the intensity of the cerebellar hemisphere. The thalamus and caudate nucleus showed macroscopically identical brightness levels; however, the intensity of the thalamus was lower than that of the caudate nucleus. The intensity of subependymal hemorrhage was lower than that of the caudothalamic groove. The intensity of subependymal cyst was the same as that of the lateral ventricle. The RF signal frequencies and intensities were distinctive in each tissue.

CONCLUSION

The results of this study suggest that measurement of RF signal intensity may be useful to differentiate macroscopically similar lesions.

Certain type of chronic lung disease of newborns is associated with Ureaplasma urealyticum infection in utero

BACKGROUND

Recent studies of chronic lung disease (CLD) of newborns emphasize the contribution of antenatal infection. However, the association of Ureaplasma urealyticum infection and CLD has been controversial. The purpose of the present paper was to determine whether U. urealyticum is associated with chorioamnionitis (CAM) and a certain type of CLD.

METHODS

One hundred and five infants <32 weeks of gestation who were admitted to the neonatal intensive care unit at Jichi Medical School Hospital, who underwent both histological and microbiological examinations and who survived to discharge were included. CAM was determined by histological examination. Placenta, gastric and tracheal aspirates, and nasopharyngeal swabs were cultured for Mycoplasma and other microorganisms. CLD was defined as oxygen needed at 28 days of age with symptoms of persistent respiratory distress and hazy or emphysematous and fibrous appearance upon X-ray. CLD was further divided into two subtypes according to the presence of antenatal infection.

RESULTS

CAM was associated with premature rupture of membrane (odds ratio [OR], 10.19; 95% confidence interval [CI]: 3.10-33.56), placental colonization of U. urealyticum (OR 6.73, 95%CI: 1.89-23.91), neonatal colonization of other microorganisms (OR 7.33, 95%CI: 1.22-44.13) and level of IgM (OR 1.06, 95%CI: 1.01-1.11). Comparisons between CLD and non-CLD patients showed that gestational age (OR 0.43, 95%CI: 0.30-0.61) and white blood cell count (WBC) at birth (OR 1.06, 95%CI: 1.01-1.11) were risk factors for CLD, while gestational age (OR 0.38, 95%CI: 0.23-0.64), neonatal colonization of U. urealyticum (OR 5.98, 95%CI: 1.17-30.6) and WBC (OR 1.08, 95%CI: 1.01-1.15) were independent risk factors for infection-related CLD compared with non-CLD. Within CLD, infection-related CLD was associated with neonatal colonization of U. urealyticum (OR 43.7, 95%CI: 2.84-673.8) and WBC (OR 1.27, 95%CI: 1.07-1.50).

CONCLUSIONS

Placental colonization of U. urealyticum was significantly related to CAM; and neonatal colonization of U. urealyticum and leukocytosis at birth were risk factors for infection-related CLD.

Utility of a Doppler-derived index combining systolic and diastolic performance (Tei index) for detecting hypoxic cardiac damage in newborns

The purpose of this study was to assess cardiac function of newborns with mild asphyxia by a Doppler-derived index combining systolic and diastolic performance (Tei index). We studied 20 preterm infants with mild asphyxia. A control group consisted of 20 gestational age-matched preterm infants without asphyxia. Echocardiograms were performed during the fourth and seventh days after birth. Peak velocities of an early filling wave (E) and an atrial contraction wave (A) were measured from the mitral inflow velocity profile and the ratio of peak E to A was calculated. Ejection time was measured from the left ventricular outflow Doppler signal. The sum of isovolumetric times was obtained by subtracting the ejection time from the interval between cessation and onset of mitral inflow. The index was the sum of isovolumetric times divided by ejection time. Ejection fraction was also calculated. The ratio of peak E to A and ejection fraction were the same in both groups. The myocardial performance index in patients with asphyxia was higher than that in patients without asphyxia. We concluded that patients with mild asphyxia have a mild cardiac dysfunction and this change can be detected by a myocardial performance index.

Developmental outcome of very low birth weight twins conceived by assisted reproduction techniques

OBJECTIVE

To evaluate the differences in developmental outcomes between very low birth weight twins conceived by assisted reproduction techniques and those conceived spontaneously.

STUDY DESIGN

Twenty-two sets of very low birth weight twins were evaluated by the Kyoto Scale for Psychological Development at 36 months of corrected age. Total developmental quotient and developmental quotient (DQ) for three subscales, posture-motor, cognition-adaptation and language-social, were evaluated.

RESULTS

Twins conceived with medical assistance demonstrated a higher incidence of total DQ below 85 with lower DQ for cognition-adaptation and language-social skills than spontaneously conceived twins, whereas the quotient for posture-motor skills in medically assisted twins was comparable to that of spontaneously conceived twins.

CONCLUSION

At 3 years of age very low birth weight twins conceived by assisted reproduction techniques demonstrated lower cognitive and language skills than twins conceived naturally.

Blood chimerism in monochorionic twins conceived by induced ovulation: Case report

A case of monochorionic twin boys delivered at 34 weeks of gestation following induced ovulation with clomiphene is described. One twin was typed as blood group AB and the other as B. Flow cytometry showed blood group chimerism. DNA polymorphism analysis of peripheral lymphocytes and hair root cells showed that the chimerism was confined to the blood cells and they were dizygotic.

Tead proteins activate the Foxa2 enhancer in the node in cooperation with a second factor

The cell population and the activity of the organizer change during the course of development. We addressed the mechanism of mouse node development via an analysis of the node/notochord enhancer (NE) of Foxa2. We first identified the core element (CE) of the enhancer, which in multimeric form drives gene expression in the node. The CE was activated in Wnt/β-catenin-treated P19 cells with a time lag, and this activation was dependent on two separate sequence motifs within the CE. These same motifs were also required for enhancer activity in transgenic embryos. We identified the Tead family of transcription factors as binding proteins for the 3′motif. Teads and their co-factor YAP65 activated the CE in P19 cells, and binding of Tead to CE was essential for enhancer activity. Inhibition of Tead activity by repressor-modified Tead compromised NE enhancer activation and notochord development in transgenic mouse embryos. Furthermore, manipulation of Tead activity in zebrafish embryos led to altered expression of foxa2 in the embryonic shield. These results suggest that Tead activates the Foxa2 enhancer core element in the mouse node in cooperation with a second factor that binds to the 5′ element, and that a similar mechanism also operates in the zebrafish shield.

The Risk of Birth Defects in Dichorionic Twins Conceived by Assisted Reproductive Technology

The purpose of this study was to examine whether dichorionic twins conceived by assisted reproductive technology (ART; intracytoplasmic sperm injection [ICSI], in vitro fertilization [IVF], gamete-intrafallopian tube transfer [GIFT]) have a higher risk of birth defects compared to dichorionic twins conceived naturally. We reviewed the medical records of 406 mothers with dichorionic twin pregnancies, who received continuous antenatal care from < or = 20 weeks of gestation and gave birth to infants after > or = 24 weeks of gestation in our institute. Birth defects were diagnosed at the time of hospital discharge according to the International Classification of Diseases, 10th Revision. Occurrence of birth defects was compared between twins conceived by ART and those conceived naturally using logistic regression analysis. Overall, 51 of 812 infants (51/812 = 6.2%) had birth defects. The incidence of birth defects in ART-conceived twins was significantly higher than that of naturally conceived twins with an odds ratio of 6.9 (95% confidence interval [CI] 2.1, 22.5), 3.7 (95% CI 1.2, 12.0), and 4.3 (95% CI 1.4, 14.3) for ICSI, IVF, and GIFT, respectively. The higher frequency of birth defects in ART-conceived twins was still significant after adjusting for higher maternal age in the ART group, with an adjusted odds ratio of 6.7 (95% CI 2.1, 21.9), 3.6 (95% CI 1.1, 11.5), and 3.7 (95% CI 1.2-11.8) for ICSI, IVF, and GIFT, respectively. Dichorionic twins conceived by ART, compared to dichorionic twins conceived naturally, had a much higher risk for birth defects diagnosed at hospital discharge.

Phylogenetic conservation of a limb-specific, cis-acting regulator of Sonic hedgehog ( Shh)

Polarized expression of the Sonic hedgehog ( Shh) gene in the posterior mesenchyme is essential for pattern formation in the appendages of higher vertebrates, from teleost fins to tetrapod limb buds. We report on a sequence in intron 5 of the Lmbr1 gene, which resides approximately 1 Mb from the Shh coding region in the mouse genome and is highly conserved among teleost fishes and throughout the tetrapod lineage. Positional cloning revealed that two mouse mutations, Hx and M100081, characterized by mirror-image digit duplication and ectopic anterior Shh expression, have base substitutions in this sequence. Absence of the conserved sequence in limbless reptiles and amphibians and a cis- trans test using the Hx and Shh KO alleles suggest that the sequence is a cis-acting regulator that controls the polarized expression of Shh.

The mouse polydactylous mutation, luxate (lx), causes anterior shift of the anteroposterior border in the developing hindlimb bud

Pattern formation along the anterior-posterior axis of the vertebrate limb is established upon activation of Sonic Hedgehog (SHH) in the zone of polarizing activity (ZPA). Since many mouse mutants with preaxial polydactyly show ectopic expression of Shh at the anterior margin of the limb buds, it has been thought to be a primary defect caused by these mutations. We show here that the mouse mutation luxate (lx) exhibits dose-dependent reduction in the size of the Fgf8 expression domain in the ectoderm from the initial stage of limb development. This aberration was independent of Fgf10 expression in the limb mesenchyme. Shh was induced in the mesenchyme underlying the posterior end of the Fgf8 expression domain, indicating an anterior shift of Shh expression in lx hindlimb buds. Prior to the ectopic induction of Shh, the expression domains of genes downstream from Shh, namely dHAND, Gli1, Ptc and Gre, which are normally expressed in posterior mesenchyme of limb buds, expanded anteriorly on the lx hindlimb buds. Conversely, the expression domains of anterior mesenchymal markers such as Gli3and Alx4 decreased in size. Thus, ectopic Shh is not a primary defect of the lx mutation. Rather, our results indicate that the lx mutation affects the positioning of the anteroposterior border in developing hindlimb buds.

A spontaneous mouse mutation, mesenchymal dysplasia (mes), is caused by a deletion of the most C-terminal cytoplasmic domain of patched (ptc)

A recessive mouse mutation, mesenchymal dysplasia (mes), which arose spontaneously on Chromosome 13, causes excess skin, increased body weight, and mild preaxial polydactyly. Fine gene mapping in this study indicated that mes is tightly linked to patched (ptc) that encodes a transmembrane receptor protein for Shh. Molecular characterization of the ptc gene of the mes mutant and an allelism test using a ptc knockout allele (ptc(-)) demonstrated that mes is caused by a deletion of the most C-terminal cytoplasmic domain of the ptc gene. Since mes homozygous embryos exhibit normal spinal cord development as compared with ptc(-) homozygotes, which die around 10 dpc with severe neural tube defects, the C-terminal cytoplasmic domain lost in mes mutation is dispensable for inhibition of Shh signaling in early embryogenesis. However, compound heterozygotes of ptc(-) and mes alleles, which survive up to birth and die neonatally, had increased body weight and exhibited abnormal anteroposterior axis formation of the limb buds. These findings indicate that Ptc is a negative regulator of body weight and ectopic activation of Shh signaling in the anterior mesenchyme of the limb buds, and that the C-terminal cytoplasmic domain of Ptc is involved in its repressive action.

Sphingosylphosphorylcholine is an activator of transglutaminase activity in human keratinocytes

We characterize functional roles of a newly discovered chemical, sphingosylphosphorylcholine (SPC), in the epidermis by elucidating the biological effect of SPC on human keratinocytes in culture. The intracellular calcium level of human keratinocytes was increased by incubation with SPC, but not with sphingosine (SS) or sphingomyelin (SM). The addition of SPC, sphingosine 1-phosphate (SSP), or SS to human keratinocytes at 10 microM concentrations also significantly suppressed DNA synthesis, and SPC, but not SSP, or SS increased the activities of membrane-bound and soluble transglutaminases (TGases). Reverse transcription polymerase chain reaction (RT-PCR) of TGase transcripts revealed that SPC treatment at 10 microM concentrations increased the expression of TGase 1 mRNA. The increased activity of soluble TGase was accompanied by the concomitant activation of cathepsin D as revealed by the increased ratio of mature active form to inactive intermediate form of the protease. Pretreatment of human keratinocytes with pepstatin, a protease inhibitor, blocked the increase in soluble TGase activity induced by treatment with SPC. Consistently, SPC treatment at 1-10 microM concentrations stimulated the cornified envelope formation. These findings suggest that SPC plays an important role in the altered keratinization process of epidermis in skin diseases with high expression of sphingomyelin deacylase, such as atopic dermatitis.

Development of a new instrument to measure oxygen saturation and total hemoglobin volume in local skin by near-infrared spectroscopy and its clinical application

The oxygen saturation (StO2) and total hemoglobin volume in cutaneous blood are closely related to cutaneous metabolism and are important factors in determining the skin color. Most conventional apparatuses for the measurement of cutaneous metabolism have been designed to evaluate qualitative changes in the oxyhemoglobin volume, deoxyhemoglobin volume, and their sum (total Hb volume) relative to their baseline values. In this study, we developed an instrument for non-invasive evaluation of individual and regional differences in StO2 and Hb volume, a system unaffected by melanin (Kao PSA system model III), and examined the validity of its application. First, changes in StO2 and total Hb volume in the antebrachial region during venous occlusion and devascularization by compression of the brachial region were evaluated. Changes in total Hb volume following venous occlusion were found to reflect the cutaneous blood flow. Also, StO2 was considered to reflect the state of oxygen consumption by the skin, because it was markedly reduced during devascularization. Next, the subjects were exposed to graded hypobaric conditions, and the relationships among StO2, arterial blood oxygen saturation (SaO2), and venous blood oxygen saturation (SvO2) were studied. StO2 showed significant positive correlations with SaO2 (r=0.811, P<0.001) and SvO2 (r=0.966, P<0.001), and its correlation with SvO2 was particularly strong. Therefore, StO2 was found to be closely dependent on SvO2. Lastly, StO2, total Hb volume, and other parameters were measured in healthy women (aged 20-69 years), and their regional differences and age-associated changes were evaluated. These regional differences (angle of mouth > cheek > forehead) and age-associated decreases in StO2 are considered to be caused by the age-associated decreases in the cutaneous blood flow.

Sphingosylphosphorylcholine is a potent inducer of intercellular adhesion molecule-1 expression in human keratinocytes

We recently reported that the epidermis of patients with atopic dermatitis contains an abnormally expressed sphingomyelin deacylase that yields a large amount of sphingosylphosphorylcholine (SPC) rather than ceramide. In this study, we characterize inflammatory roles of newly discovered chemicals in the epidermis by elucidating biologic effects of SPC on intercellular adhesion molecules-1 (ICAM-I) expression by human keratinocytes in culture in comparison with other sphingolipids. Using fluorescence-activated cell sorter analysis, we found that SPC treatment at concentrations of 10-20 microM significantly enhanced the expression of ICAM-I by cultured human keratinocytes in a dose-dependent manner after incubation for 15-24 h, and, using northern blot analysis, that this was accompanied by increased expression of ICAM-1 mRNA within 4 h of incubation. Transforming necrosis factor-alpha (TNF-alpha) levels in the medium of keratinocytes treated at a 10 microM concentration of SPC were significantly increased by 200%. Furthermore, the SPC-induced ICAM-1 expression was partially abolished by the concomitant addition of anti-TNF-alpha, suggesting a partial autocrine involvement of TNF-alpha in ICAM-1 expression. Assay of mitogen-activated protein kinase revealed that 10 microM SPC induced a rapid activation of mitogen-activated protein kinase in human keratinocytes, including an increase in its phosphorylation within 5 min, which then declined to the baseline control level after 30 min. In contrast, sphingomyelin or sphingosine had no significant potential to activate mitogen-activated protein kinase at the same concentration. These findings suggest that SPC plays an important role in the inflammatory process of epidermis in skin diseases, such as atopic dermatitis, with high expression of sphingomyelin deacylase.

Biological characterization of human fibroblast-derived mitogenic factors for human melanocytes

To clarify the paracrine linkage between human fibroblasts and melanocytes in cutaneous pigmentation, we studied the effects of human fibroblast-derived factors on the proliferation of human melanocytes. In medium conditioned for 4 days with human fibroblast culture, factors were produced that markedly stimulated DNA synthesis of human melanocytes. The stimulatory effect was higher in medium conditioned with fibroblasts from aged skin than in medium conditioned with fibroblasts from young skin, and was interrupted by inhibitors of tyrosine kinase, such as tyrphostin, genistein and herbimycin, but not by inhibitors of protein kinases C and A, such as H-7 and phloretin. The conditioned medium was also capable of activating mitogen-activated protein kinase of human melanocytes, with old fibroblasts being more effective than young ones. Analysis of factors released into the conditioned medium revealed that levels of hepatocyte growth factor (HGF) and stem cell factor (SCF) were increased in old-fibroblast-conditioned medium compared with young-fibroblast-conditioned medium. In contrast, levels of basic fibroblast growth factor (bFGF) were similar in both media. When the conditioned medium was treated with HGF antibody with or without SCF antibody, the increase in DNA synthesis by human melanocytes was decreased to 20% of the elevated level, whereas antibodies to bFGF had no effect. Analysis of the medium conditioned for 4 days after cytokine application demonstrated that, of the cytokines tested, interleukin 1alpha and tumour necrosis factor alpha are highly effective in stimulating HGF secretion by old fibroblasts. HGF and SCF, but not bFGF, were markedly increased in culture medium in the presence of IL-1alpha, and this stimulatory effect was confined to young human fibroblasts. These findings suggest that SCF and HGF derived from human fibroblasts may play a part in regulating cutaneous pigmentation during inflammation and aging.

Purification and characterization of an allergy-induced melanogenic stimulating factor in brownish guinea pig skin

We have demonstrated recently that phenylazonaphthol (PAN) allergy-induced hyperpigmentation in brownish guinea pig skin is associated with the concomitant appearance of a melanogenic soluble factor(s) that activates the intracellular signal transduction system, including phosphatidylinositol turnover subsequent to ligand-receptor binding in cultured guinea pig melanocytes. In this study we have purified and characterized the PAN-induced melanogenic stimulating factor (PIMSF) that occurs in allergy-associated hyperpigmented skin. By successive column chromatography on TSK 2000SW, Mono Q, and octadecyl-NPR, the PIMSF was purified to homogeneity with a single band of apparent molecular mass of 7.9 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The specific bioactivity of PIMSF increased by 5,195-fold over the original skin homogenate. In cultured guinea pig melanocytes, this purified PIMSF had the potential of activating an intracellular signal transduction system such as inositol 1,4,5-trisphosphate formation and intracellular calcium levels through a pertussis toxin-sensitive G protein-coupled receptor. PIMSF consistently caused a rapid translocation of cytosolic protein kinase C (PKC) to membrane-bound PKC within 5 min of treatment with a return to the basal level after 120 min. The stimulating effects of PIMSF on proliferation and melanization of cultured guinea pig melanocytes were abolished completely by a PKC down-regulating agent (phorbol 12,13-dibutyrate). PIMSF was similar in molecular mass to rat growth-related oncogene alpha (GRO-alpha; molecular mass of 7.9 kDa) on sodium dodecyl sulfate-polyacrylamide gel electrophoresis and had immunocross-reactivity with GRO-alpha upon Western immune blotting analysis. Further, the stimulatory effect of purified PIMSF on DNA synthesis of cultured guinea pig melanocytes was suppressed markedly by the addition of anti-rat GRO-alpha antibody, implying that the PIMSF is apparently identical to GRO-alpha. These findings suggest that PAN allergy provides a new mechanism of hyperpigmentation in which biological factors such as the GRO-alpha superfamily generated within allergy-induced skin stimulate melanocytes through activation of the PKC-related signal transduction pathway.

The role of endothelin-1 in epidermal hyperpigmentation and signaling mechanisms of mitogenesis and melanogenesis

The paracrine linkage of endothelins (ET) between keratinocytes and melanocytes suggested that ETs are intrinsic mediators for human melanocytes in UVB-induced pigmentation. In this study, the role of ET-1 in the epidermal hyperpigmentation was investigated in vivo and in vitro. The addition of 10 nM ET-1 induced a H-7 (10 microM) suppressible-increase in tyrosinase activity in cultured human melanocytes and was accompanied by elevated levels of tyrosinase and tyrosinase-related protein-1 mRNA expression as shown by Northern blotting. Analysis of signaling mechanisms leading to tyrosinase activation demonstrated the involvements of quick translocation of PKC, the H-7 (10 microM) suppressible-phosphorylation of the threonine residue of several proteins, and highly elevated level of cyclic AMP (4-fold over control). Reverse transcription polymerase chain reaction (RT-PCR) of RNA isolated from the epidermis of human skin exposed to UVB revealed that UVB irradiation with a dose of 2 MED caused a significant increase in the expressions of ET-1, IL-1 alpha, and tyrosinase mRNA signals 5 days after irradiation. The involvement of ET-1 in UVB-pigmentation was also corroborated by the experiments that the extracts of M. Chamomilla, which can act as an antagonist for ET-receptor binding-mediated signaling but has no inhibitory effect on tyrosinase activity in culture, had a significant inhibitory effect on UVB-induced pigmentation in vivo when daily applied immediately after UVB exposure to human skin. These findings suggest that ET-1 is an important mediator in the epidermis for UVB-induced pigmentation in vivo.

Abnormal expression of sphingomyelin acylase in atopic dermatitis: an etiologic factor for ceramide deficiency?

Previously, we demonstrated that there is a marked reduction in the amount of ceramide in the stratum corneum of both lesional and nonlesional forearms in atopic dermatitis (AD), suggesting that an insufficiency of ceramides in the stratum corneum is an etiologic factor in atopic dry and barrier-disrupted skin. In this study, we investigated, as a possible mechanism involved in the ceramide deficiency, whether sphingomyelin (SM) metabolism is altered in AD as compared to normal controls. In stripped stratum corneum and biopsied whole epidermis of patients with AD, SM hydrolysis as measured at pH 4.7 using [choline-methyl-14C]sphingomyelin as a substrate were markedly increased by 27- and 7-fold, respectively. Radio-thin-layer chromatography of the reaction products revealed that, whereas the SM hydrolysis in age-matched normal controls were associated with sphingomyelinase (SMase) that degrades SM to yield ceramides and phosphorylcholine (PC), most of the SM hydrolysis detected in AD were attributable not to the SMase but to a hitherto undiscovered epidermal enzyme, SM acylase, which releases free fatty acid and sphingosyl-PC (Sph-PC) instead of ceramides. The potential of this acylase-like enzyme to generate Sph-PC through SM hydrolysis was corroborated by thin-layer chromatographic analysis of the reaction products obtained using porcine kidney acylase, followed by high-performance liquid chromatography-mass spectrometry. Furthermore, Sph-PC was also detected by high-performance liquid chromatography-mass spectrometry after incubation of SM with atopic stratum corneum samples. On the other hand, the stratum corneum of patients with contact dermatitis or chronic eczema exhibited neither increased SM hydrolysis nor the generation of Sph-PC upon radio-thin-layer chromatographic analysis. These findings suggest that SM metabolism is altered in AD, resulting in a decrease in levels of ceramides, which could be an etiologic factor in the continuous generation of atopic dry and barrier disrupted skin observed in AD.

Signalling mechanisms of endothelin-induced mitogenesis and melanogenesis in human melanocytes

To understand the signalling mechanisms involved in the dual stimulatory effects of endothelin-1 (ET-1) on DNA synthesis and melanization in cultured human melanocytes, we analysed the biological profile of ET-1 receptor and determined the effects of ET-1 on the protein kinase C, cyclic AMP system and mitogen-activated protein kinase (MAP kinase) in comparison with their relevant stimulants. The photoaffinity labelling of ET-1 receptors with Denny-Jaff reagents revealed an ET-1 receptor with a molecular mass of 51 kDa in human melanocytes. The ET(A) receptor subtype-sensitive antagonist BQ123(50 nM) or pertussis toxin (100 ng/ml) significantly suppressed the ET-1-induced intracellular calcium mobilization, indicating the presence of pertussis toxin-sensitive G-protein-coupled ET(A) receptors. An assay of protein kinase C activity revealed that 10nM ET-1 translocated cytosolic protein kinase C to membrane-bound protein kinase C within 5 min of the start of incubation. In contrast, receptor-mediated melanocyte activation by ET-1 was accompanied by an elevated level of cyclic AMP (4-fold over control) after 10-60 min of incubation, whereas 60 min of incubation of human melanocytes with c-Kit or c-Met ligands such as stem cell factor (10 nM) or basic fibroblast growth factor (10 nM) did not elevate the cyclic AMP level. We have also demonstrated that a specific tyrosine kinase inhibitor, tyrphostin B-42 (10 microM), inhibited the ET-1-induced growth stimulation, suggesting the involvement of the tyrosine kinase pathway in growth stimulation. Consistently, an assay of MAP kinase revealed that ET-1 caused a 10-fold activation of MAP kinase after 5 min of incubation with human melanocytes in a similar way to tyrosine kinase ligands such as stem cell factor and hepatocyte growth factor. Further, the DNA synthesis stimulated by the c-Kit ligand stem cell factor at a concentration of 1 nM was synergistically enhanced by 5 nM ET-1. These results suggest that ET-induced dual cellular events in human melanocytes are closely associated with cross-talk between the protein kinase C and A and tyrosine kinase pathways.