Above 25 nm emission wavelength shift in blue-violet InGaN quantum wells induced by GaN substrate misorientation profiling: towards broad-band superluminescent diodes

We report a thorough study of InGaN quantum wells spatially modified by varying the local misorientation of the GaN substrate prior to the epitaxial growth of the structure. More than 25 nm shift of emission wavelength was obtained, which is attributed to indium content changes in the quantum wells. Such an active region is promising for broadening of the emission spectrum of (In,Al,Ga)N superluminescent diodes. We observed that the light intensity changes with misorientation, being stable around 0.5° to 2° and decreasing above 2°. This relation can be used as a base for future device designing.

Evaluation of the non-functional tooth contact in patients with temporomandibular disorders by using newly developed electronic system

The aims of this study were to introduce a novel electronic system for reliable evaluation of the non-functional tooth contact in patients with temporomandibular disorders (TMDs) and investigate the possible associations between the non-functional tooth contact and some characteristics of the patients with TMD. We designed and installed a software program to send emails regarding the non-functional tooth contact to the subjects' preregistered cellular phones at intervals of 20 ± 9 min daily for 10 consecutive days. Twelve patients with TMD and 12 gender- and age-matched healthy subjects responded via emails to one of 3 choices: no tooth contact, tooth contact during oral functions or tooth contact not associated with oral functions. The influence of subjective stress, anxiety, depression, personality and daily activities on tooth contact was then assessed. The frequency of the non-functional tooth contact was significantly higher in the patients with TMD than in the healthy subjects (35·0% vs. 9·6%, P < 0·001), while no significant group difference was found for the frequency of functional tooth contact, the stress, anxiety, depression and personality.

Instrumentation for dual-probe scanning near-field optical microscopy

To investigate local carrier motions, we developed a dual-probe scanning near-field optical microscope (SNOM) with two fiber probes where one is for photoexcitation and the other is for light collection. This instrumentation is based on two important techniques: the design of probe structures and distance control between the sample surface and the two probes. A finite-difference time-domain method numerically analyzed and optimized the design for high efficiency photoexcitation and light collection, while a dual band modulation realized distance control. Real time detection of the oscillations of the probe tips using different frequencies independently controls the distance between the probe tip and the sample surface as well as the distance between the two probes. Thus, the collection probe can be scanned around an illumination probe without destroying the probe tips. To demonstrate our SNOM, we performed photoluminescence spectroscopy under the dual-probe configuration and observed carrier motions in an InGaN quantum well.

Single mode emission and non-stochastic laser system based on disordered point-sized structures: toward a tuneable random laser

As an advantage, random lasers may be elaborated from a large variety of materials and do not require any cavity oscillators that usually necessitate complicated and expensive fabrication techniques. Since the feedback process of those non-conventional laser systems is provided by light interference in a disordered medium, spectral and temporal uncertainties are usually considered as an intrinsic part of their optical proprieties. We investigated random laser action under two photon absorption experiments through an auto-organized InGaN/GaN quantum-disks ensemble. Thanks to our experimental approach, we evidence random lasing based on a gain medium constituted by point-sized structures. In such context, a stabilised and individual emission mode is observed as for conventional semiconductor lasers. By controlling the emission energy of these nanostructures, a tuneable and stable random laser may be built. Moreover, our findings suggest that disordered medium should play an important role in the conception of low cost quantum dot and up conversion laser systems.

Optical gain spectra for near UV to aquamarine (Al,In)GaN laser diodes

Optical gain spectra presented for (Al,In)GaN laser diodes with lasing wavelength ranging from UV (375 nm) to aquamarine (470 nm) show a strong increase in inhomogeneous broadening, caused by Indium composition and quantum well width fluctuations which increase with Indium mole fraction. These gain spectra provides a standard data set for the calibration of microscopic many-body simulations. We demonstrate by comparison with basic simulations that the different assumptions of a global constant carrier density or of global constant quasi-Fermi levels for electrons and holes lead to a strikingly different dependency of optical gain on carrier density. For constant quasi-Fermi levels the threshold carrier density becomes insensitive to inhomogeneous broadening for realistic parameters. This is in agreement with the observation that the threshold current is nearly independent over the wavelength range from near UV to aquamarine.

Direct ligand-receptor complex interaction controls Brassica self-incompatibility

Many higher plants have evolved self-incompatibility mechanisms to prevent self-fertilization. In Brassica self-incompatibility, recognition between pollen and the stigma is controlled by the S locus, which contains three highly polymorphic genes: S-receptor kinase (SRK), S-locus protein 11 (SP11) (also called S-locus cysteine-rich protein; SCR) and S-locus glycoprotein (SLG). SRK encodes a membrane-spanning serine/threonine kinase that determines the S-haplotype specificity of the stigma, and SP11 encodes a small cysteine-rich protein that determines the S-haplotype specificity of pollen. SP11 is localized in the pollen coat. It is thought that, during self-pollination, SP11 is secreted from the pollen coat and interacts with its cognate SRK in the papilla cell of the stigma to elicit the self-incompatibility response. SLG is a secreted stigma protein that is highly homologous to the SRK extracellular domain. Although it is not required for S-haplotype specificity of the stigma, SLG enhances the self-incompatibility response; however, how this is accomplished remains controversial. Here we show that a single form of SP11 of the S8 haplotype (S8-SP11) stabilized with four intramolecular disulphide bonds specifically binds the stigma membrane of the S8 haplotype to induce autophosphorylation of SRK8, and that SRK8 and SLG8 together form a high-affinity receptor complex for S8-SP11 on the stigma membrane.

Upshaw-Schulman syndrome revisited: a concept of congenital thrombotic thrombocytopenic purpura

Upshaw-Schulman syndrome (USS) is a congenital bleeding disorder characterized by repeated episodes of thrombocytopenia and microangiopathic hemolytic anemia that respond to infusions of fresh frozen plasma. Inheritance of USS has been thought to be autosomal recessive, because 2 siblings in the same family are often affected but their parents are asymptomatic. Recently, chronic relapsing thrombotic thrombocytopenic purpura (CR-TTP), reported almost exclusively in adults, was shown to be caused by inherited or acquired deficiency in the activity of a plasma von Willebrand factor-cleaving protease (vWF-CPase). The pathogenesis of USS is unknown, and a relationship between CR-YEP and USS has not been reported. We studied 3 unrelated USS patients (ST, SY, and KI) who presented with severe indirect neonatal hyperbilirubinemia. All 3 patients had undetectable vWF-CPase activity, and the inhibitors to vWF-CPase were all negative. In their parents with no clinical symptoms, vWF-CPase activities as a percentage of control samples (mother/father) were 17/20 for ST, 60/45 for SY, and 36/5.6 for KI. Thus, USS and vWF-CPase activity appear to be coinherited as autosomal recessive traits. Transfusion of fresh frozen plasma in 2 patients (ST and SY) resulted in the expected maximal increment of approximately 7% to 8% in vWF-CPase activity at 1 to 4 hours, but the levels became less than 3% within 2 days. After this decrease, platelet counts increased, plateaued in the normal range at 10 to 12 days, and declined thereafter. Thus, the 2 to 3 weeks of therapeutic benefit from plasma infusions will be discussed in relation to the intravascular lifetime of vWF-CPase.

A pollen coat protein, SP11/SCR, determines the pollen S-specificity in the self-incompatibility of Brassica species

Many flowering plants have evolved self-incompatibility (SI) systems to prevent inbreeding. In the Brassicaceae, SI is genetically controlled by a single polymorphic locus, termed the S-locus. Pollen rejection occurs when stigma and pollen share the same S-haplotype. Recognition of S-haplotype specificity has recently been shown to involve at least two S-locus genes, S-receptor kinase (SRK) and S-locus protein 11 or S-locus Cys-rich (SP11/SCR). SRK encodes a polymorphic membrane-spanning protein kinase, which is the sole female determinant of the S-haplotype specificity. SP11/SCR encodes a highly polymorphic Cys-rich small basic protein specifically expressed in the anther tapetum and in pollen. In cauliflower (B. oleracea), the gain-of-function approach has demonstrated that an allele of SP11/SCR encodes the male determinant of S-specificity. Here we examined the function of two alleles of SP11/SCR of B. rapa by the same approach and further established that SP11/SCR is the sole male determinant of SI in the genus Brassica sp. Our results also suggested that the 522-bp 5'-upstream region of the S9-SP11 gene used to drive the transgene contained all the regulatory elements required for the unique sporophytic/gametophytic expression observed for the native SP11 gene. Promoter deletion analyses suggested that the highly conserved 192-bp upstream region was sufficient for driving this unique expression. Furthermore, immunohistochemical analyses revealed that the protein product of the SP11 transgene was present in the tapetum and pollen, and that in pollen of late developmental stages, the SP11 protein was mainly localized in the pollen coat, a finding consistent with its expected biological role.

Prospective study of mother-to-infant transmission of hepatitis C virus

BACKGROUND

Mother-to-infant transmission of hepatitis C virus (HCV) could become the main route of HCV infection in the future because there are no methods available to prevent vertical infection. The aim of this study was to determine the incidence of mother-to-infant transmission in infants born to mothers who tested positive for anti-HCV antibodies and to elucidate associated risk factors for transmission.

METHODS

Screening was conducted for 16,800 pregnant women with an anti-HCV antibodies test, and 154 mothers were positive. From the positive group 141 mothers were enrolled in the study and their 147 infants were followed from birth for serum alanine aminotransferase activity, anti-HCV antibodies and HCV RNA. HIV infection was tested in 73 of 141 mothers, all of whom were negative.

RESULTS

Thirty-three infants were dropped from the study because they were followed for <6 months or were not tested adequately. Of the 114 infants finally evaluated 9 (7.8%) had detectable HCV RNA. The transmission rate was not influenced by the mode of delivery [vaginal delivery, 8 of 90 vs. cesarean section, 1 of 24 (P = 0.396)] or by the type of feeding [9 of 98 for breast-fed infants vs. 0 of 16 for formula-fed infants (P = 0.243)]. All infected infants were born to mothers who had HCV viremia at the delivery (P = 0.040) and to those with a high viral load (P = 0.019).

CONCLUSIONS

Our prospective study showed that the transmission rate of mother-to-infant HCV infection was 7.8% in anti-HCV antibody-positive mothers. Risk was related to the presence of maternal HCV viremia at delivery and a high viral load in the mothers.

Measurement of bone mineral density of lumbar spine and whole body in low-birth-weight infants: comparison of two methods

In the present study, we compared lumbar spinal and whole-body bone mineral density (BMD) measurements to determine which is more suitable for evaluating the bone mineral status of low-birth-weight (LBW) infants. Lumbar spinal and whole-body BMD were assessed simultaneously in a prospective series including 152 Japanese LBW infants (birth weight 453-2400 g, gestational age 24-38 weeks) from the age of 40 weeks post-conception to 2 years of age. Lumbar spinal BMD at 40 weeks post-conception was significantly correlated with birth weight (r = 0.74; P < 0.0001), but wholebody BMD was not correlated with birth weight. No correlation was found between lumbar spinal and whole-body BMD at 40 weeks post-conception. However, after 40 weeks post-conception, a significant correlation was found between lumbar spinal and whole-body BMD (r = 0.65; P < 0.0001). For infants with a body weight of 4 kg or less at the time of measurement, no correlation was found between lumbar spinal and whole-body BMD. However, for infants with a body weight above 4 kg, a significant correlation was found between lumbar spinal and whole-body BMD (r = 0.65; P < 0.0001). Thus, lumbar spinal BMD is more suitable than whole-body BMD for evaluation of the bone mineral status of LBW in early infancy. Therefore, lumbar spinal BMD should be used for serial evaluation of changes in the bone mineral status of LBW infants.

A novel mutation (296 del G) of the SOX90 gene in a patient with campomelic syndrome and sex reversal

The human SOX9 gene is responsible for the campomelic syndrome (CMPS) and sex reversal. This gene encodes a transcription factor containing a DNA binding domain homologous to the SRY high mobility group (HMG) domain. A novel mutation of SOX9, i.e. a single G deletion in one allele at nt 296 from A of the first ATG in the open reading frame, was identified in a patient with CMPS with sex reversal. The deletion resulted in a frameshift mutation upstream of the HMG box and a stop codon 30 bp downstream of the HMG box. The predicted truncated SOX9 protein contained 108 amino acids instead of the 509 amino acids of the normal SOX9 protein, removing nearly 80% of the SOX9 protein, including the HMG and the C-terminal transactivation domain. Most patients with CMPS reported previously died within the neonatal period. Our findings that the patient has survived, although has been in daily need of mechanical ventilation support for 5 years and 3 months despite a severely impaired SOX9 protein, do not support a linear relationship between the type of mutation and severity of the clinical outcome.

Bone mineral density of the lumbar spine in very-low-birth-weight infants: a longitudinal study

To examine osteopenia in very low birth weight (VLBW) infants we used repeated dual-energy X-ray absorptiometry in a prospective study of lumbar spinal bone mineral density (BMD) in Japanese VLBW infants (birthweight 426-1498 g; n = 61, group 1) aged 40 weeks postconception to 3 years of age. Control subjects were Japanese infants with birthweight 1500-1999 g (group 2), 2000-2499 g (group 3), or more than 2500 g (group 4). BMD in group 1 during the early period after birth was very low, increased rapidly for 1 year, and then gradually increased until 3 years of age (r = 0.931, P < 0. 0001). BMD at the age of 40 weeks postconception was 0.085 +/- 0.026, 0.132 +/- 0.039, 0.178 +/- 0.042, and 0.196 +/- 0.046 g/cm(2) in groups 1, 2, 3, and 4, respectively (P < 0.0001). However, at 1 and 2 years of age no differences were observed among the groups in BMD.

CONCLUSION

This study shows that lumbar spinal BMD in VLBW infants can normalize by the age of 2 years.

Correlation between magnetic resonance imaging and clinical profiles of periventricular leukomalacia

Magnetic resonance imaging (MRI) findings of 70 children with periventricular leukomalacia (PVL), examined between 1 year 2 months and 8 years of age (mean: 2 years 4 months of age), were analysed. Neurological assessments were made between 1 year 3 months and 15 years (mean: 4 years 9 months). The possible correlations between MRI findings and clinical profiles of PVL were investigated using three parameters of the MRI findings. The grade of ventriculomegaly correlated well with the severity of cerebral palsy (CP) but not with the severity of mental impairment. The grade of reduction of periventricular white matter correlated well with the severity of CP and mental impairment, and is the most reliable parameter for neurological prognosis. The degree of periventricular hyperintensity on T2-weighted images did not correlate well with severity of CP, but correlated to some degree with mental impairment. There was a significantly lower degree of periventricular hyperintensity in children at less than 28 weeks of gestation than at 28 or more weeks of gestation, but no significant difference in other parameters. The periventricular hyperintensity should be evaluated in view of the gestational age.

Transient increase in cerebral blood flow in a patient with Sturge-Weber syndrome

We report the case of an infant with Sturge-Weber syndrome whose regional cerebral blood flow (rCBF) showed an increase and a subsequent decrease. As compared with simultaneous CT and MR findings, we speculate that the transient increase in rCBF reflects the neuronal reaction to hypoxia caused by congestion.

[A case of acute necrotizing encephalopathy of childhood with a good outcome]

We experienced a case of acute necrotizing encephalopathy of childhood with a good outcome. The disease continued for about three weeks, and the patient recovered with a sequela of mild left-hemiparesis. On the brain magnetic resonance imaging, abnormal intensity areas in the thalamus and putamen reduced size at an early stage of the disease. After 1 year, his mental and motor development seemed to be almost normal, but brain single photon emission computed tomography and electroencephalography were abnormal. Subclinical functional abnormalities persisted longer than had been expected.

National survey of periventricular leukomalacia in Japan

BACKGROUND

Clarification of the present status of periventricular leukomalacia (PVL) in Japan.

METHODS

Questionnaires were mailed to the leading neonatal intensive care units (NICU) and rehabilitation centers for children.

RESULTS

The incidence of PVL in the group of surviving preterm infants of gestational ages less than 33 weeks was 4.8-4.9% on ultrasound and 7.7-7.9% on magnetic resonance imaging and/or computed tomography. The incidence of PVL did not decrease between 1990 and 1994. The incidence of PVL in the NICU varied from 0 to 47.1%. Infants from multiple pregnancies had a higher incidence (9.1%) of PVL than those from single pregnancies (6.2%). The proportion of PVL in all patients in rehabilitation centers with cerebral palsy (CP) has increased recently.

CONCLUSIONS

It was roughly calculated that about 750 cases of CP with PVL occurred annually in Japan, thus accounting for about one-third of the total number of cases of CP.

Trends in neonatal exchange transfusions at Yodogawa Christian Hospital

A review was conducted to determine the trends in exchange transfusion (ET) of newborn infants at the Yodogawa Christian Hospital during the past 18 years. At that hospital in 1957, the first ET was performed on a term infant with severe hemolytic jaundice caused by rhesus factor (Rh) incompatibility. By 1989, ET had been performed in more than 1400 newborn infants. These cases of newborns who had had ET were retrospectively reviewed, with a focus on every 3 year period from 1974 to 1992. The total number of infants requiring ET noticeably decreased from 68 cases (14.0% of total admissions) in 1974 to 19 cases (6.1% of total admissions) in 1992. (chi 2, P < 0.001) There were three major significant changes in ET during those years. The first was a change in the subjects for ET. The incidence of ET for term infants showed a marked decrease, while the incidence of ET for preterm infants, especially for very low birthweight (VLBW) infants (< 1500 g), noticeably increased. The second was a change in indications for ET. There was a marked decrease in the need for ET as a result of hyperbilirubinemia, while the incidence of ET because of other etiologies, such as septicemia and/or disseminated intravascular coagulopathy, noticeably increased. The third was a change in the technical methods of ET. Now at the Yodogawa Christian Hospital, 100% of the infants are given ET with an automated peripheral two-site method, instead of the Diamond method. Although ET might still be a useful treatment for severe hyperbilirubinemia and other acute problems, the total number of ET noticeably decreased in accord with a decrease in the number of severe hyperbilirubinemia in term newborns. On the other hand, the incidence of ET in preterm infants increased relatively, accompanied by an increase in the survival of VLBW infants. The automated two-site method is the preferred technique for ET at the Yodogawa Christian Hospital, rather than the Diamond method. Further changes in ET might occur in accord with new alternative measures in future.

[Quality of life of children with chronic neurological diseases: introductory remarks]

Recent advances in medical technology, such as an assisted ventilation, have made a big impact on pediatrics. With such a progress, many children with intractable diseases have survived intact. On the other hand, chronically ill children with handicaps have also been increasing. Some of them have been artificially supported by a respirator to maintain life in a hospital or at home. Under these social conditions, we should establish a system for total care of these children, to promote their quality of lives, in collaboration with medicine, health & welfare, and education.

Haemodynamic effects of differing blood transfusion rates in infants less than 1500 g

OBJECTIVE

To investigate whether the haemodynamic effects of the standard 2-3 h blood transfusion increases the risk for intraventricular haemorrhage (IVH) and patent ductus arteriosus (PDA) in very low birthweight infants.

METHODOLOGY

In a randomized controlled study, haemodynamic changes using slow and rapid transfusion were compared. Twenty-seven very low birthweight infants were divided between 12h (n = 14) and 3h (n = 13) transfusion groups. Blood pressure, ejection fraction (EF), anterior cerebral artery pulsatility index (PI), blood gases, serum electrolytes and haematocrit were measured pre- and post-transfusion. Infectious status was also monitored.

RESULTS

Blood pressure (48.1/25.5 vs 55.7/30.2 mmHg) and EF (0.68 vs 0.73) increased significantly during rapid transfusion (P<0.01) but remained stable with slow transfusion. Serum potassium, base excess and incidence of infection did not increase in either group.

CONCLUSIONS

Slow transfusion causes less haemodynamic disturbance than rapid transfusion, thereby preventing the potential risk for IVH and PDA.

Follow-up study of auditory brainstem responses in hyperbilirubinemic newborns treated with exchange transfusion

Changes in auditory brainstem responses (ABR) were studied and followed in hyperbilirubinemic newborns before and after exchange transfusion (ET), in order to check their usefulness in the early detection of acute and chronic bilirubin encephalopathy. ABR were measured in 10 newborns with marked hyperbilirubinemia (total bilirubin concentration [TBC] > or = 20 mg/dL, direct bilirubin concentration < 2 mg/dL) before and after ET. The means of birthweight, gestational age, and day of life on admission were 3267 g, 38.2 weeks and 3.4 days, respectively. The ABR measurements were performed before ET and 6.0 days (the mean) after the ET. The follow-up of ABR was performed at 3 months of life. In comparison with the control values, the mean latencies of ABR were significantly prolonged (I, I-III, and I-V: P < 0.05) and the mean amplitudes were significantly decreased (I, III and V: P < 0.001) before ET. Significant improvement of ABR was noticed after the ET, especially in the shortening of the latency of wave I (P < 0.02) and in increasing the amplitudes of wave III and V (P < 0.02 and (P < 0.01, respectively), though the recovery of the latency of I-V (P < 0.02) and the amplitudes of I, III and V wave (P < 0.001, P < 0.001 and P < 0.01, respectively) were delayed in comparison to the control. The follow-up data of ABR showed that, in two of nine infants (one was lost from the follow-up), there were still abnormal findings at 3 months of age. Only one of these, who prolonged the recovery of ABR until 5 years of age, developed a border intelligence. Though ET is effective for improvement of acute bilirubin encephalopathy with impaired ABR, a complete recovery of the ABR might be delayed in marked hyperbilirubinemia. The delay in improvement of ABR abnormalities might be possibly used as an early predictor for following chronic bilirubin encephalopathy.

Home mechanical ventilation in the aftermath of the Hanshin-Awaji earthquake disaster

Children who were dependent upon home mechanical ventilation (HMV), suffered in various ways from the disastrous Hanshin-Awaji earthquake disaster. The earthquake abruptly cut the supplies of water, gas and electricity, causing intense anxiety for those families. Through loss of the respirator function, some of them experienced an unexpected catastrophe. In the disaster area, there were children who were dependent upon HMV (19 cases) and children who were preparing for HMV in hospitals (nine cases). Information was gathered from questionnaires about the disaster, communication and correspondence with families. None of the 28 cases died or were injured. Nineteen cases had a variety of problems. In eight cases, respiratory support problems were acute. Nevertheless, all of them survived the crisis successfully even in the midst of such a catastrophic situation. An organization of HMV children's families, called the Baku-Baku Club, helped families with HMV problems by supplying water, food, oxygen and compressed air cylinders among other things. Additional outside batteries for portable respirators are essential equipment for HMV, especially for emergencies. A manual for clarifying the system for support in the Baku-Baku Club and a registration system for public medical service should be established in preparation for such a crisis.

Vigintiphobia, unbound bilirubin, and auditory brainstem responses

OBJECTIVE

The management of nonhemolytic hyperbilirubinemia in term newborns is controversial. To evaluate the usefulness of serum unbound bilirubin concentrations (UBCs) in the management of hyperbilirubinemia, we compared the concentrations with abnormal auditory brainstem responses (ABRs).

METHODS

ABRs and serum UBCs in 37 hyperbilirubinemic term newborns (total bilirubin concentrations [TBCs] > or = 20 mg/dL and direct bilirubin concentrations < 2 mg/dL) were measured before treatment with either phototherapy or exchange transfusions. Eight of these newborns had blood incompatibilities. These hyperbilirubinemic newborns were divided into three groups according to the findings of ABR: group A, normal ABR (n = 18); group B, prolonged latency of wave I only (n = 8); and group C, prolonged interpeak latency of wave I-III/I-V and/or poor amplitude (n = 11).

RESULTS

The peak TBC was significantly different between groups A and C (22.8 +/- 2.2 mg/dL and 25.4 +/- 2.5 mg/dL, respectively; P < .05), though there were no differences between groups A and B and between groups B and C. The peak UBCs in groups B (1.27 +/- 0.7 micrograms/dL) and C (1.34 +/- 0.37 micrograms/dL) were significantly higher than in group A (0.78 +/- 0.26 microgram/dL) (P < .05 and P < .01, respectively), though there was no significant difference in the peak UBC between groups B and C. Abnormal ABR findings were more clearly associated with the level of UBC at 1.0 microgram/dL than that of TBC at 23 mg/dL by multiple logistic regression analysis (odds ratio = 16.6, P = .0026, vs 4.2, P = .1272).

CONCLUSIONS

These results suggest that measuring UBC may help in evaluating the possible risk of bilirubin encephalopathy in full-term newborns when there is vigintiphobia (fear of 20).

Determination of serum unbound bilirubin for prediction of kernicterus in low birthweight infants

Serum unbound bilirubin concentrations (UBC) and serum total bilirubin concentrations (TBC) were measured serially in 138 low birthweight (LBW) infants treated with phototherapy for non-hemolytic hyperbilirubinemia. We attempted to assign the suitable critical UBC levels for predicting bilirubin encephalopathy into two different birthweight groups: a very low birthweight (VLBW) group (birthweight < 1,500 g) and an LBW group (birthweight between 1,500 g and 2,499 g). Twelve infants were diagnosed as 'at risk' for kernicterus, of whom 11 had signs of acute bilirubin encephalopathy and received exchange transfusion. One VLBW infant had neurological sequelae at a 3 year follow-up, although exchange transfusion was not carried out because of low TBC. Sensitivity and specificity for predicting kernicterus were calculated at different UBC levels between 0.6 microgram/dl and 1.5 micrograms/dl and TBC levels between 8 mg/dl and 26 mg/dl. The receiver-operating characteristic (ROC) curves plotted for UBC as a predictor of kernicterus were clearly shifted up and to the left compared with the curves for TBC in the VLBW and LBW groups. Thus, the UBC measurement may well provide a more rational basis for evaluating the risk of kernicterus in LBW infants. The optimal cut-off points were derived from these curves. In the VLBW group, the sensitivity was 100% and the specificity was 96% for a UBC of 0.8 microgram/dl, and 80% and 64% for a TBC of 11 mg/dl. In the LBW group, the sensitivity was 100% and the specificity was 98% for a UBC of 1.0 microgram/dl and 71% and 78% for a TBC of 16 mg/dl.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical events in association with timing of intraventricular hemorrhage in preterm infants

To ascertain whether any routine practices or clinical manipulations in a neonatal intensive care unit could induce intraventricular hemorrhage (IVH) in preterm infants, we performed ultrasonic monitoring of the germinal layer continuously for 48 hours in 33 extremely premature infants with respiratory distress. Intraventricular hemorrhage developed in 16 of these infants. In four infants the timing of the germinal layer hemorrhage was confirmed with ultrasonic monitoring. Three of the four cases were apparently associated with clinical events occurring at the moment of IVH: manual ventilation for improvement of hypercapnia associated with primary pulmonary hypertension of the newborn; correction of hyperkalemia, which was causing an arrhythmia, with administration of calcium gluconate and sodium bicarbonate; and administration of surfactant-TA to improve respiratory failure caused by pulmonary hemorrhage. In these three infants it appeared that one of the basic factors inducing IVH might be an increase in blood pressure with or without hypercapnia, causing cerebral reperfusion after ischemic damage of the germinal layer.

Two patients with chromosome 6q terminal deletions with breakpoints at q24.3 and q25.3

We report on 2 patients with de novo terminal deletion of 6q. The first was a 4-month-old boy whose karyotype was 46,XY,del(6)(q24.3); the second a 2-year-old girl whose karyotype was 46, XX, del(6)(q25.3). The main anomalies in both patients included mental retardation, minor craniofacial and cerebral anomalies, and cardiac defects. The characteristic manifestations were imperforate anus in the first patient, and retinitis proliferans and a triatrial heart in the other. Comparison of clinical findings of our 2 patients with those of 18 previously reported patients with similar phenotypes suggests that terminal deletion of the 6q23 or 6q25 band is critical in producing the main anomalies of del(6q) syndrome.

[Myelination in very low birth weight infants--evaluation by MRI]

The prognostic significance of cerebral myelination was evaluated with magnetic resonance imaging (MRI) in very low birth weight infants. Myelination was graded in two specified sites, optic radiation and corpus callosum, based on the stages of normal term babies and healthy premature infants. The subjects were 30 preterm infants weighing less than 1,500 gm at birth. MRI was performed at 4 to 7 months (corrected age). The normal myelination stage was seen in 18 cases, while a delayed stage was noticed in 12 cases. In the normal myelination group, only 1 case (6%) had handicaps. In the delayed myelination group, 8 cases (67%) had handicaps. Our results showed that delayed myelination was closely related to a poor prognosis. We believe that MRI would be a very good imaging modality for predicting the outcome of very low birth weight infants, particularly in terms of evaluation of myelination.

[A brief respite from hospital: home mechanical ventilation for children in Japan]

Children who require prolonged respiratory support often have to spend their whole lives in the hospital. It is important, however, for these children to have time with their families in their own homes. Home mechanical ventilation can make it possible. In Japan, the concept of home mechanical ventilation has just begun to open up. We reported five cases of home mechanical ventilation for children by using a portable respirator (Bennett, Companion 2800). Two cases of these were patients with hypoxic ischemic encephalopathy. The others were cases with neuro-muscular diseases (Werdnig-Hoffmann disease, mitochondrial myopathy, myotubular myopathy). Before taking the patients out, parents received a training in nursing procedures and in skillful use of the ventilator and equipment. The patients went out on excursions 17 times, and were released for home stay a total of 25 times. Initially, 12 excursions were undertaken with doctors or nurses in attendance; later, however, all of the home stays and 5 of the excursions were carried out successfully by the family only. They went to places such as their own home, a park, a zoo, an aquarium and a museum. The average time was 4.6 hours (3-8 hours) for excursions, and 1.8 days (1-7 days) for home stays. Questioning of family revealed that home mechanical ventilation accelerated the social and emotional development of these children whose condition necessitated respiratory support, especially patients with neuro-muscular diseases. It also revealed that family could accept the patient as a member with more familiarity and with more ease.(ABSTRACT TRUNCATED AT 250 WORDS)

Automated exchange transfusion and exchange rate

An automated blood exchange transfusion (BET) with a two-site technique has been devised by Goldmann et al and by us, using an infusion pump. With this method, we successfully performed exchange transfusions 189 times in the past four years on 110 infants with birth weights ranging from 530 g to 4,000 g. The exchange rate by the automated method was compared with the rate by Diamond's method. Serum bilirubin (SB) levels before and after BET and the maximal SB rebound within 24 hours after BET were: 21.6 +/- 2.4, 11.5 +/- 2.2, and 15.0 +/- 1.5 mg/dl in the automated method, and 22.0 +/- 2.9, 11.2 +/- 2.5, and 17.7 +/- 3.2 mg/dl in Diamond's method, respectively. The result showed that the maximal rebound of the SB level within 24 hours after BET was significantly lower in the automated method than in Diamond's method (p less than 0.01), though SB levels before and after BET were not significantly different between the two methods. The exchange rate was also measured by means of staining the fetal red cells (F cells) both in the automated method and in Diamond's method, and comparing them. The exchange rate of F cells in Diamond's method went down along the theoretical exchange curve proposed by Diamond, while the rate in the automated method was significantly better than in Diamond's, especially in the early stage of BET (p less than 0.01). We believe that the use of this automated method may give better results than Diamond's method in the rate of exchange, because this method is performed with a two-site technique using a peripheral artery and vein.

Influence of drugs on albumin and bilirubin interaction

Twenty-eight drugs, including cephem antibiotics and anti-inflammatory agents currently used or considered potentially useful in neonatal intensive care nurseries in Japan, were examined to determine their influence on albumin and bilirubin interaction by means of a glucose oxidase - peroxidase method, using an automated analyzer (Arrows) for unbound bilirubin (U.B.). The apparent binding constant for drugs to the high-affinity site on albumin (KD) was determined. Of cephem antibiotics, latamoxef sodium (LMOX) and cefazolin sodium (CEZ) were found to displace bilirubin from albumin (KD = 5.9 x 10(3) M-1 and 4.5 x 10(3) M-1, respectively) as strongly as Na salicylate (KD = 6.8 x 10(3) M-1). Mephenamate and indomethacin, which are used for medical closure of patent ductus arteriosus in premature infants, were also found to be stronger bilirubin displacers (KD = 1.3 x 10(5) M-1 and 1.2 x 10(5) M-1, respectively) than sulfisoxazole (KD = 1.6 x 10(4) M-1). Maximal displacement factors (MDF's) were also estimated in reference to protein binding (%) and effective serum concentration (M) of each drug in human adults. Of these drugs, mephenamate showed a higher risk of bilirubin displacement (MDF = 3.79) than sulfisoxazole (MDF = 2.58) and LMOX had a higher risk of displacement (MDF = 1.97) than Na salicylate (MDF = 1.85). On the other hand, indomethacin and CEZ showed minimal effects on displacement at therapeutic levels (MDF = 1.03 and 1.00, respectively). At therapeutic serum levels, mephenamate and LMOX may possess the potential for displacing bilirubin from albumin and increasing the risk of bilirubin encephalopathy, in a manner similar to sulfisoxazole.

The moment of intraventricular hemorrhage

A continuous monitoring of the germinal layer by linear scanning ultrasound has been proposed for the purpose of ascertaining the moment of intraventricular hemorrhage (IVH). Using a VHS videotape, we performed the 48 hours monitoring in 7 immature infants weighing less than 1,000 g who required respiratory support. Four cases of these developed IVH. In one case, which was 755 g in birth weight and 24 weeks in gestational age, the moment of IVH was successfully demonstrated on the ultrasonic monitor. At that moment, there were no significant changes in heart rate and systemic blood pressure. No direct manipulation or treatment, such as an endotracheal suctioning or a heel puncture which might induce a blood pressure fluctuation, was being given at the moment of IVH. About 15 minutes after the episode, abnormal seizure-like movement periodically developed.

Elevated immunoglobulin M levels in low birth-weight neonates with chronic respiratory insufficiency

Ten babies weighing less than 1500 g at birth subsequently developed chronic respiratory insufficiency and bubbly appearance on chest X-ray during their infancy. The clinical diagnoses were compatible with Wilson-Mikity syndrome. They were compared with very low birth-weight infants who did not show these signs and symptoms. On the first day (mean) of life significantly high serum immunoglobulin M levels were found in the study group. The possibility exists that the chronic respiratory insufficiency seen in these very low birth-weight infants may have been caused by intrauterine infection.

Rapid changes of serum vasoactive intestinal peptide after removal of ganglioneuroblastoma with watery-diarrhea-hypokalemia-achlorhydria syndrome in a child

A 23-month-old girl with intractable diarrhea that had persisted for the past 6 months showed typical evidence of water-diarrhea-hypokalemia-achlorhydria (WDHA) syndrome. Serum vasoactive intestinal peptide (VIP)-like immunoactivity was very high, and urine homovanillic acid and noradrenaline were also abnormally increased. A calcified tumor in the right paravertebral region was noted radiologically. Soon after resection of the tumor, the diarrhea dramatically improved. A ganglioneuroblastoma was histologically confirmed. Serum VIP decreased to normal level at 1 h after the removal of the tumor. VIP activity in the tumor was extraordinarily high, and the cells were stained by the indirect immunofluorescence technique with anti-VIP serum. This is to report the rapid turnover of serum level of VIP after resection of ganglioneuroblastoma with WDHA syndrome in a child.