Decreased susceptibility to seizures induced by pentylenetetrazole in serine racemase knockout mice.

The N-methyl-D-aspartate (NMDA)-type glutamate receptor plays a key role in excitatory synaptic transmission. The overactivation of the NMDA receptor has been implicated in the development of epileptic seizures. D-Serine is a coagonist of the NMDA receptor and its biosynthesis is catalyzed by serine racemase (SR). Here, we examined the effect of d-serine deficiency on the seizures induced by a single injection of pentylenetetrazole (PTZ) using SR knockout (KO) mice. We found that, compared with wild-type (WT) mice, SR-KO mice showed the attenuation of seizure expression in terms of a significantly shortened duration of generalized seizures and resistance to generalized clonic-tonic seizures. Consistently, immunohistochemical analysis of c-Fos demonstrated that the numbers of cells expressing c-Fos induced by high-dose PTZ in the cerebral cortex, hippocampal CA1, hippocampal CA3, and the basolateral nucleus of the amygdala in WT mice were significantly higher than those in SR-KO mice. Moreover, PTZ induced an increase in extracellular glutamate level in the dentate gyrus of WT mice at two different time phases. However, such a PTZ-induced increase in glutamate level was completely inhibited in SR-KO mice. The present findings suggest that SR may be a target for the development of new therapeutic strategies for epileptic seizures.

Intracranial calcification in a uremic infant with Wilms' tumor in a solitary kidney.

Wilms' tumor (WT), also called nephroblastoma, is an embryonic neoplasm of the developing kidney. A previously healthy Japanese female infant had WT in a single kidney without associated congenital malformations. Preoperative chemotherapy was started for the preservation of renal tissue and function. Tumor lysis syndrome, disseminated intravascular coagulopathy, and acute renal failure were accompanying. The infant needed surgical intervention and permanent replacement therapy. At the start of emergency hemodialysis, the infant had posterior reversible leukoencephalopathy syndrome because of severe hypertension. During ongoing peritoneal dialysis, the infant suffered from anemia, dietary and fluid restriction, and restriction of time and mobility. Despite alfacalcidol and calcium supplementation, the infant had secondary hyperparathyroidism and remarkably short stature. After waiting for the completion of chemotherapy, renal transplantation from the mother was completed. Successful kidney transplantation promptly corrected preexisting metabolic abnormalities causing secondary hyperparathyroidism. Subsequently, the infant often complained of headache. Computed tomographic scanning revealed calcification in the cerebellum. Refractory secondary hyperparathyroidism was inferred as the cause. A well-functioning graft provided the infant with a greater sense of well-being and enabled her to enjoy a lifestyle free of dialysis, although the infant must continue taking transplant medications and has retained unresolved issues of short stature and ectopic intracranial calcification.

A novel immunoregulatory protein in human colostrum, syntenin-1, for promoting the development of IgA-producing cells from cord blood B cells.

Human colostrum contains many bioactive factors that must promote the development of intestinal mucosal immunity in infants. Especially, the presence of certain cytokines such as transforming growth factor (TGF)-beta or IL-10 has been of great interest for IgA production as a function of mucosal immune response. In the present study, we attempted to investigate whether unidentified factors inducing generation of IgA-producing cells from naive B cells might exist in colostrum. For this purpose, colostrum samples were directly added to a culture consisting of naive B cells and dendritic cells from cord blood and CD40 ligand-transfected L cells, comparing with recombinant IL-10 (rIL-10) and/or rTGF-beta. It was noted that most colostrum samples alone were able to induce IgA-secreting cells at higher levels than rIL-10 and/or rTGF-beta. IgA-inducing activity of colostrum was abolished by neither anti-neutralizing mAbs against IL-10 nor TGF-beta, though partially by anti-IL-6 mAb. We prepared partially purified fractions from both pooled colostrums with and without IgA-inducing activity and comparatively performed quantitative proteomic analysis by two-dimensional difference gel electrophoresis followed by liquid chromatography-mass spectrometry. As a result, syntenin-1 was identified as a candidate for IgA-inducing protein in colostrum. Western blot analysis indicated that levels of syntenin-1 in colostrum samples were correlated with their IgA-inducing activities. Moreover, we demonstrated that recombinant syntenin-1 could induce preferentially IgA production from naive B cells. These results suggest that syntenin-1 serves as one of IgA-inducing factors for B cells.

Role of transforming growth factor-beta in breast milk for initiation of IgA production in newborn infants.

BACKGROUND: Transforming growth factor (TGF)-beta has a crucial effect on IgA production, which is the major humoral effector of mucosal immunity. Breast milk contains the abundant amount of TGF-beta in the early period of lactation. AIM-STUDY DESIGN: To verify the notion that TGF-beta in breast milk might contribute to the development of IgA production in newborns, we investigated the association of TGF-beta in maternal colostrum with an increase of serum IgA in newborns during the first month of life. SUBJECTS AND METHODS: The concentrations of TGF-beta1 and TGF-beta2, including IL-6 and IL-10, in colostrum samples from 55 healthy mothers were determined by ELISA. The levels of IgA and IgM in serum samples collected from corresponding newborn babies at birth and at 1 month of age were measured by ELISA. RESULTS: TGF-beta1 and TGF-beta2 were detected in substantial quantities in all colostrum samples, but IL-6 and IL-10 were present only in a proportion of samples. An increase of serum IgA in newborn during the first month of life was significantly higher than that of serum IgM (p<0.001). Notably, an increase of serum IgA in newborns during 1 month of life was well correlated with levels of both TGF-beta1 (r=0.38, p=0.005) and TGF-beta2 (r=0.45, p=0.0005) in colostrum, while that of IgM was marginally correlated with colostral TGF-beta2 (r=0.28, p=0.04). The association of increase of serum IgA in newborns with IL-6 and IL-10 in colostrum was not evident. CONCLUSION: Our findings suggest that TGF-beta in colostrum might serve as the starter of IgA production in newborn infants.

Female agammaglobulinemia due to the Bruton tyrosine kinase deficiency caused by extremely skewed X-chromosome inactivation.

We analyzed the cause of agammaglobulinemia in a girl whose father had been diagnosed as having X-linked agammaglobulinemia (XLA). Flow cytometric analysis revealed the lack of peripheral B cells with the block of B-cell differentiation in the stages between pro-B cells and pre-B cells in the bone marrow, and the defect of the Bruton tyrosine kinase (BTK) expression on monocytes. We found a BTK gene mutation in the first single base pair of intron 11 in her father and heterozygous mutation in the patient at the site. Sequence analysis of abnormally smaller-sized polymerase chain reaction (PCR) products of cDNA confirmed splicing abnormalities due to the mutation. Maternally derived X chromosome was exclusively inactivated in peripheral blood and oral mucosal cells. This is the first report of female XLA caused by heterozygous BTK gene abnormality and extreme nonrandom inactivation of X chromosome on which normal BTK gene is located.

Identification of mutations of Bruton's tyrosine kinase gene (BTK) in Brazilian patients with X-linked agammaglobulinemia.

Mutations in the Bruton tyrosine kinase (BTK) gene are responsible for X-linked agammaglobulinemia (XLA), which is characterized by recurrent bacterial infections, profound hypogammaglobulinemia, and decreased numbers of mature B cells in the peripheral blood. We evaluated 17 male Brazilian patients from 13 unrelated families who showed markedly reduced numbers of blood B cells and hypogammaglobulinemia. BTK gene analysis detected mutations in 10 of the 13 presumed XLA families. Seven mutations (Q196X, G613D, R28L, 251-273del, Q234X, H364P, and R13X) had been reported previously, whereas the remaining three mutations (M501T, IVS15+1G>C, and IVS14+1G>A) were novel. Mutation IVS15+1G>C occurred in a splice donor site and caused exons 15 and 16 to be skipped, and IVS14+1G>A might cause exon 14 to be skipped. Flow cytometry revealed deficient expression of BTK protein in 10 of the 13 families. This is the first report of the diagnosis of XLA by analysis of mutations of the BTK gene in Brazilian patients.