Masahiro Nagaya

Mutations in SIP1 , encoding Smad interacting protein-1, cause a form of Hirschsprung disease

Hirschsprung disease (HSCR) is sometimes associated with a set of characteristics including mental retardation, microcephaly, and distinct facial features, but the gene mutated in this condition has not yet been identified. Here we report that mutations in SIP1, encoding Smad interacting protein-1, cause disease in a series of cases. SIP1 is located in the deleted segment at 2q22 from a patient with a de novo t(2;13)(q22;q22) translocation. SIP1 seems to have crucial roles in normal embryonic neural and neural crest development.

Clinical and molecular analysis of Mowat-Wilson syndrome associated with ZFHX1B mutations and deletions at 2q22–q24.1

Hirschsprung disease (HSCR), a clinically complex syndrome often associated with a combination of mental retardation, microcephaly, and characteristic facial features, is genetically heterogeneous.1–10 Recently, mutations in ZFHX1B , which encodes Smad-interacting protein 1 (SIP1), were identified by our group11 and Cacheux et al 12 in patients with t(2;13)(q22;q22) and t(2;11)(q22.2;q21), respectively. These patients had clinical profiles consistent with a dominant form of the disease (Mowat-Wilson syndrome: MIM 235730).9,13 These and subsequent articles have demonstrated a link between patients with nonsense and frameshift mutations of the gene and the presence in these patients of the following clinical findings: profound mental retardation, delayed motor development, and specific facial features, including hypertelorism, a broad nasal bridge, strabismus, a pointed chin, prognathism, a nose with a prominent columella, and posteriorly rotated ears. Often associated with these features were microcephaly, epilepsy, congenital heart disease, HSCR, and midline defects such as agenesis or hypoplasia of the corpus callosum and hypospadias.13–19 This variety of clinical features is observed not only in patients with nonsense and frameshift mutations but also in patients harbouring deletions involving ZFHX1B at 2q22,9,11,15,20 including a previously reported isolated case.6 Thus, ZFHX1B clearly plays a critical role in the manifestation of clinical features of Mowat-Wilson syndrome. However, several points remain to be elucidated: (1) How broad are the clinical features in patients with ZFHX1B mutations and deletions? (2) What are the underlying molecular mechanisms by which the deletion of ZFHX1B at 2q22 affects the clinical phenotype? (3) What kind of clinical features might appear if the deletions were extended to include 2q23–q24.1? To address these questions, we have characterized the clinical features and underlying molecular basis of 27 cases with mutations or deletions in ZFHX1B , including 12 previously reported cases comprising …

High levels of immunoreactive nervous system-specific enolase in sera of patients with neuroblastoma

Serum levels of nervous system-specific enolase (NSE, gamma gamma form plus alpha gamma form) in patients with neuroblastoma and in control subjects were determined with a sensitive solid-phase sandwich enzyme immunoassay system. Serum levels of NSE in healthy adults ranged from 1.4-5.7 ng/ml (2.87 +/- 1.18 ng/ml, n = 20), and in control children (1-7 years old) from 2.6 to 10.8 ng/ml (5.76 +/- 2.42 ng/ml, n = 20). Serum samples (n = 13) from patients with neuroblastoma contained high levels of NSE, range 13.6 to 330 ng/ml (mean 96 ng/ml); however those (n = 7) from ganglioneuroblastoma patients were within a normal range (3.0-25.0 ng/ml; mean 8.3 ng/ml). These results suggested that the NSE in serum might be a valuable marker substance for screening and therapeutic monitoring of neuroblastoma.

Sensor and regulator proteins from the cyanobacterium Synechococcus species PCC7942 that belong to the bacterial signal‐transduction protein families: implication in the adaptive response to phosphate limitation

A 1.2kb DNA fragment was cloned from Synechococcus sp. PCC7942, which is able phenotypicalty to complement a phoRcreC Escherichia coli mutant for the expression of alkaline phosphatase. A 2.5kb DNA fragment encompassing the putative gene was then cloned and its complete nucleotide sequence determined. Nucleotide sequencing revealed that the intact gene encodes a protein of 46389 Da, and that the deduced amino acid sequence shows a high degree of homology to those of the bacterial sensory kinase family. In the determined nucleotide sequence, another gene was adjacently located, which encodes a protein of 29012Da. This protein shows a high degree of homology to those of the response regulator family. Thus, we succeeded in the cloning of a pair of genes encoding the sensory kinase and response regulator, respectively, in a cyanobacterium. Mutant strains that lack these genes were constructed, and demonstrated to be defective in their ability to produce alkaline phosphatase and some inducible proteins in response to phosphate‐limitation in the medium. These results imply that the gene products identified in this study are probably involved, either directly or indirectly, in the signal‐transduction mechanism underlying regulation of the phosphate regulon in Synechococcus sp. PCC7942. Hence, the genes encoding the sensory kinase and response regulator were designated as sphS and sphR, respectively (Synechococcusphosphate regulon). The SphS protein was demonstrated in vitro to undergo phosphorylation in the presence of ATP.

Development in lung function of the affected side after repair of congenital diaphragmatic hernia

The widespread use of newly developed techniques including extracorporeal membrane oxygenation (ECMO) has led to the survival of a number of patients with congenital diaphragmatic hernia (CDH) and associated hypoplastic lung. However, it is not fully recognized whether the hypoplastic and small lung of the affected side has the ability to develop its function after repair of CDH. The authors studied the lung function of 32 patients with CDH in whom these new methods were used. Two parameters, lung volume and pulmonary perfusion amount, were used to evaluate lung function. The former (checked by computed tomography scan) was used to evaluate the size of lung; the latter (checked by perfusion scintigram) was used to assess vascular density. The patients were divided into two groups, based on values of alveolar-arterial difference in oxygen content (AaDo2) at the time of admission. In group A (AaDo2 < 500 mm Hg; 12 cases), whose respiratory distress was mild and could be managed with ventilator care alone, the mean lung volume value for the affected side was 86% of the contralateral lung value from the initial study, and reached 93% at the time of follow-up study. The perfusion amount also exceeded 80% of the contralateral lung value from the initial study. Thus, it is likely that group As affected-side lung is not small and has developed at a rate similar to that of the contralateral lung. However, in group B patients (AaDo2 > 500 mm Hg; 20 cases), who had severe respiratory distress at the admission and were managed with new techniques including ECMO, both lung volume and perfusion amount of the affected side initially were low in all cases (ie, mean values were 61% and 53% of contralateral-lung values, respectively). At the time of follow-up, the lung volume had increased in most cases (mean value, 88% of the contralateral lung value), but the perfusion amount of the affected side had not increased in most cases. It remained low, or decreased to below the initial value; the mean was 53% of the contralateral lung value. The initial mean perfusion: volume ratio (87%) had decreased significantly (to 62%) by the time of follow-up. This tendency was exaggerated in the 11 ECMO cases. These data might indicate that in most group B cases, the lung of the affected side has little ability to develop arterial branches, or certainly will be delayed in comparison to the contralateral lung, and that enlargement of lung volume may depend on overexpansion or emphysematous change rather than cellular growth. The present data also suggest that, in group B cases, total lung function will depend on the contralateral lung for a relatively long time.

Pancreaticobiliary maljunction without choledochal cysts in infants and children: Clinical features and surgical therapy

Pancreaticobiliary maljunction (PBM) usually is associated with choledochal cyst. PBM without dilatation of the common bile duct is rare in infants and children. This rare type of the anomaly may lead to the development of malignancy of the bile duct in later life. The authors report the clinical presentation and surgical treatment of seven pediatric patients with PBM. Symptoms and signs included repeated episodes of abdominal pain (7 of 7), nausea and vomiting (6 of 7), intermittent jaundice (3 of 7), and acholic stools (2 of 7). Some patients presented with high levels of serum and urinary amylase. These symptoms and signs might have been related to the temporary obstruction of bile flow in the common channel, where endoscopic retrograde cholangiopancreaticography (ERCP) disclosed a protein plug in four of the patients. The common bile duct proximal to the junction of the main pancreatic duct was excised, and a Roux-en-Y hepaticojejunostomy reconstruction was performed. To prevent iatrogenic injury of the main pancreatic duct, repeat cholangiography was performed with the aid of radiopaque silver clips placed on the line of dissection to evaluate the distance between the site of dissection and the main pancreatic duct. All patients have been free of symptoms since the surgery. PBM without dilatation of the common bile duct can be detected more frequently if ERCP is performed on every patient who has repeated episodes of abdominal pain refractory to conventional therapy. Complete excision of the common bile duct and gallbladder followed by hepaticojejunostomy is recommended for PBM, while the goals of decreasing the high risk of carcinoma of the bile duct and preventing recurrent symptoms.

Enhancement of S-100β protein in blood of patients with down’s syndrome

The human gene encoding the β subunit of S-100 protein (S-100β) was mapped on chromosome 21. In order to confirm the expression of gene-dosage effect of S-100β in patients with Down’s syndrome (DS), concentrations of immunoreactive S-100α and S-100β proteins were determined in the blood plasma and lymphocytes fraction of the patients and control subjects. Cu/Zn-superoxide dismutase (SOD), a protein that is known to show the gene-dosage effect on the trisomy of chromosome 21, also was immunoassayed in the same blood samples as control proteins. In blood plasma, S-100β protein as well as Cu/Zn SOD was enhanced (P<0.001) in the patients (160±70 pg S-100β/ml and 87±83 ng SOD/ml, N=44) as compared with control individuals (76±25 pg/ml, and 18±11 ng/ml, respectively, N=28). However, concentrations of S-100α in blood plasma of DS patients were similar to those of normal subjects. Concentrations of S-100β in lymphocyte fractions of DS patients (24.7±10.9 ng/mg protein) were also higher (P<0.001) than those of control subjects (10.1±5.8 ng/mg protein). These results indicate that gene-dosage effect of S-100β levels are expressed in DS patients.

Late infantile Hirschsprung disease–mental retardation syndrome with a 3-bp deletion in ZFHX1B

A 48-year-old woman with late infantile onset mental retardation developed megacolon. Although the patient had no typical clinical features of Hirschsprung disease–mental retardation syndrome, a new 3–base pair deletion, eliminating an Asn, was identified in the responsible gene ZFHX1B. This suggests that screening for ZFHX1B mutations is warranted even in the absence of typical clinical features of the syndrome.

Cloning of a sensory-kinase-encoding gene that belongs to the two-component regulatory family from the cyanobacterium Synechococcus sp. PCC7942

A screening method employing Escherichia coli was adopted to clone a sensory-kinase (SK)-encoding gene directly from a phylogenetically distant species, the phototrophic cyanobacterium Synechococcus sp. PCC7942. From the Synechococcus chromosomal DNA, we searched for DNA clones which are able to complement phenotypically not only an E. coli envZ mutant for the expression of ompC, but also an E. coli phoR/creC mutant for the expression of alkaline phosphatase. These E. coli genes are known to encode SK. A 0.75-kb DNA fragment was thus cloned under the control of the E. coli lac promoter carried on an E. coli plasmid vector. A larger DNA fragment encompassing an entire open reading frame was then cloned and its complete nucleotide (nt) sequence determined. The nt sequence corresponds to a gene that encodes a 43,280-Da protein of 387 amino acids with a high degree of homology to the bacterial SK. Thus, we succeeded in cloning a SK-encoding gene, which most likely functions in signal transduction in Synechococcus sp. PCC7942. Hence, the gene was designated sasA (Synechococcus adaptive-response SK A). The purified SasA protein was demonstrated in vitro to undergo autophosphorylation.

Comparison of venoarterial versus venovenous access in the cerebral circulation of newborns undergoing extracorporeal membrane oxygenation

Abstract This study was designed to compare venoarterial (VA) with venovenous (VV) access in the cerebral circulation of newborn infants during extracorporeal membrane oxygenation (ECMO). Among 14 infants with VA ECMO, 7 had no intracranial complications (group 1), while the others (group 2) developed intracranial hemorrhage (ICH). In contrast, among 19 infants with VV ECMO, only 1 developed ICH. Serial echocardiograms were performed before and after 1, 6, 12, and 24 h and 2 and 3 days of ECMO. The mean cerebral blood flow (CBF) velocities were measured in the anterior cerebral artery (ACA), right and left internal carotid arteries (Rt, Lt-ICA), basilar artery (BA), and right and left middle cerebral arteries (Rt, Lt-MCA). Ejection fraction (EF), cardiac output (CO), and stroke volume (SV) were also measured using standard echography. The velocity levels in the ACA, Rt-MCA, and Lt-MCA in VA ECMO were lower than those in VV ECMO, while those in the Lt-ICA and BA in VA ECMO were higher than those in VV ECMO. The EF, CO, and SV were lower in cases of VA ECMO than in VV ECMO. In cases of VA ECMO, there were no differences between groups 1 and 2 in velocities in the ACA, Rt-ICA, or Lt-ICA. However the velocities in group 2 in the BA, Rt-MCA, and Lt-MCA were lower than those in group 1 before and during ECMO. Similarly, the EF, CO, and SV were lower in group 2 (12.0%–31.0%, 0.10–0.32 l/min, and 0.66–1.55 ml, respectively) than in group 1 (29.5%–49.3%, 0.25–0.63 l/min, and 2.15–3.85 ml) during ECMO. However, in the infants on VV ECMO the CBF was either maintained or gradually increased before and during ECMO. Their cardiac parameters were: EF 46.1%–53.0%, CO 0.43–0.52 l/min, and SV 2.72–3.84 ml during ECMO. It is concluded that in VA ECMO CBF velocities, particularly in infants who developed ICH, decreased after the onset of ECMO in association with poor cardiac function, while in VV ECMO they were stable, probably due to normal systemic hemodynamics and cardiac function.