Phenotypic differences in hiPSC NPCs derived from patients with schizophrenia.

Consistent with recent reports indicating that neurons differentiated in vitro from human-induced pluripotent stem cells (hiPSCs) are immature relative to those in the human brain, gene expression comparisons of our hiPSC-derived neurons to the Allen BrainSpan Atlas indicate that they most resemble fetal brain tissue. This finding suggests that, rather than modeling the late features of schizophrenia (SZ), hiPSC-based models may be better suited for the study of disease predisposition. We now report that a significant fraction of the gene signature of SZ hiPSC-derived neurons is conserved in SZ hiPSC neural progenitor cells (NPCs). We used two independent discovery-based approaches-microarray gene expression and stable isotope labeling by amino acids in cell culture (SILAC) quantitative proteomic mass spectrometry analyses-to identify cellular phenotypes in SZ hiPSC NPCs from four SZ patients. From our findings that SZ hiPSC NPCs show abnormal gene expression and protein levels related to cytoskeletal remodeling and oxidative stress, we predicted, and subsequently observed, aberrant migration and increased oxidative stress in SZ hiPSC NPCs. These reproducible NPC phenotypes were identified through scalable assays that can be applied to expanded cohorts of SZ patients, making them a potentially valuable tool with which to study the developmental mechanisms contributing to SZ.

Brain amino acid sensing.

The 20 different amino acids, in blood as well as in the brain, are strictly maintained at the same levels throughout the day, regardless of food intake. Gastric vagal afferents only respond to free glutamate and sugars, providing recognition of food intake and initiating digestion. Metabolic control of amino acid homeostasis and diet-induced thermogenesis is triggered by this glutamate signalling in the stomach through the gut-brain axis. Rats chronically fed high-sugar and high-fat diets do not develop obesity when a 1% (w/v) monosodium glutamate (MSG) solution is available in a choice paradigm. Deficiency of the essential amino acid lysine (Lys) induced a plasticity in rats in response to Lys. This result shows how the body is able to identify deficient nutrients to maintain homeostasis. This plastic effect is induced by activin A activity in the brain, particularly in certain neurons in the lateral hypothalamic area (LHA) which is the centre for amino acid homeostasis and appetite. These neurons respond to glutamate signalling in the oral cavity by which umami taste is perceived. They play a quantitative role in regulating ingestion of deficient nutrients, thereby leading to a healthier life. After recovery from malnutrition, rats prefer MSG solutions, which serve as biomarkers for protein nutrition.

Effective method of monitoring cerebral tissue oxygen saturation in cardiac surgery patients by combined use of tNIRS-1 and bispectral index.

To continuously and noninvasively monitor the cerebral tissue oxygen saturation (StO2) and hemoglobin concentration (gasHb) in cardiac surgery patients, a method combining the use of a cerebral tissue oximeter using near infrared time-resolved spectroscopy (tNIRS-1) and the bispectral index (BIS) was developed in this study. Moreover, the correlation between the estimated hemoglobin concentration (estHb), measured via tNIRS-1, and the hemoglobin concentration (gasHb), analyzed using a blood gas analyzer, were compared. The relationship between the BIS and gasHb was also examined. Through the comparison of BIS and StO2 (r1), and estHb and gasHb (r2), the correlation between the two was clarified with maximum r1 and r2 values of 0.617 and 0.946, respectively. The relationship between BIS and gasHb (r3), showed that there was a favorable correlation with a maximum r3 value of 0.969. There was also a continuous correlation between BIS and StO2 in patients undergoing cardiac surgery. In addition, a strong correlation was found between estHb and gasHb, and between BIS and gasHb. It was therefore concluded that the combined use of BIS and tNIRS-1 is useful to evaluate cerebral hypoxia, allowing for quick response to cerebral hypoxia and reduction of hemoglobin concentration during the operation.

Human herpes virus 8-negative primary effusion lymphoma with BCL6 rearrangement in a patient with idiopathic CD4 positive T-lymphocytopenia.

Primary effusion lymphoma (PEL) was initially designated as a body-cavity-based lymphoma and recognized as a distinct clinical entity without a contiguous tumor mass. PEL was first reported in patients with acquired immunodeficiency syndrome (AIDS) and the distinctive feature of PEL originally reported as a B-cell neoplasm characterized by infection of the tumor cells by human herpes virus 8 (HHV-8). However, there have recently been several reports of PEL in patients without human immunodeficiency virus (HIV) or HHV-8 infection.

Receptor kinase activation and signal transduction in plants: an emerging picture.

Plant receptor kinases play key roles in the cell-cell recognition process during development, defense against pathogens, and self incompatibility. Recent identification of potential ligand molecules and downstream signaling components, together with biochemical studies on receptor-complex formation, have revealed an emerging picture of receptor-kinase activation and signal transduction in plants.

Biochemical studies of taste sensation. IX. Enhancement of L-[3H]glutamate binding to bovine taste papillae by 5'-ribonucleotides.

The interaction of the taste substance monosodium L-glutamate with taste receptors has been investigated. Binding of L-[3H]glutamate was measured to preparations of bovine circumvallate (taste) papillae (type I preparation) and to control tongue epithelial preparations (type II preparation) devoid of taste receptors. Binding is operationally defined using a membrane filtration assay. Substantially greater binding occurred to the type I preparation than to the type II preparation, and the binding to the type I preparation showed evidence of saturation. The apparent Kd of L-glutamate was estimated to be in the range of 20--30 mM. The unique taste effect of L-glutamate was considered to depend importantly on its demonstrated synergism in combination with certain 5'-ribonucleotides. A several-fold enhancement of binding of L-[3H]glutamate occurred in the presence of certain 5'-ribonucleotides. 5'-GMP, 5'-IMP and 5'-UMP each increased the binding of L-[3H]glutamate, while 5'-XMP, 5'-AMP and 5'-CMP did not. None of these nucleotides affected the lower level of binding to the type II preparation. Neither the free bases, adenine and guanine, their nucleosides nor their di- or triphosphonucleotides were effective in increasing L-[3H]glutamate binding to the type I preparation. The nucleotide specificity of the glutamate binding enhancement therefore shows a marked similarity with the nucleotide specificity in evoking the synergistic taste effect in humans.

Purification and characterization of alpha-glucosidases produced by Saccharomyces in response to three distinct maltose genes.

alpha-Glucosidases or maltases (EC 3.2.1.20) were purified to electrophoretic homogeneity from a respective strain of Saccharomyces cerevisiae which carries a single MAL gene, either MAL alpha, MAL beta, or MAL gamma, using gluconate-Sepharose affinity chromatography and isoelectrofocusing. Of these maltases, two types of maltase were obtained from the MAL gamma strain, the pI values of which were 5.6 and 5.9. From the MAL alpha and MAL beta strain was obtained only one type of maltase with the pI at 5.6 which was identical to one of the maltases from the MAL gamma strain. These four maltases possessed the same properties, except for pI. They were monomers with molecular weights of between 66 000 and 67 000. With regard to the substrate specificity, they hydrolyzed maltose and sucrose exclusively but not alpha-methylglucoside nor maltooligosaccharide. They did not differ in immunological properties.

Studies on the binding of adenylyl-3', 5'-cytidine to ribonuclease.

The interaction of adenylyl-3',5'-cytidine (ApC) with ribonuclease-A (RNAase-A) was studied by steady-state kinetics and ultraviolet difference spectroscopy. X-ray difference Fourier synthesis at 4 A resolution was also used to study the binding of ApC to RNAase-S. Unlike well-studied compounds like uridylyl-3',5'-adenosine, ApC binds in an unique way: (1) the cytidine moiety is bound to the B1 and R1 sites, (2) the adenosine moiety protrudes to the solution and is not fixed spatially and (3) the phosphate group is bound to the non-specific site (the "Po site") previously postulated (Sawada, F. and Irie, M. (1969) J. Biochem. (Tokyo) 66, 415--418) as the binding site for the 5'-phosphate of uridine 2',5'-diphosphate or uridine 3',5'-diphosphate. This conclusion is consistent with that derived for adenylyl-3',5' -4-thiouridine based on CD difference spectroscopy (White, M.D., Keren-Zur, M. and Lapidot, Y. (1977) Nucleic Acid Res. 4, 843--851). The "Po site" is most likely the epsilon-amino group of Lys 66.

Relationship between polyamine contents and protease activity in the rat submaxillary gland.

The effect of polyamines on the protease activity in the submaxillary gland of castrated rats has been investigated in vivo. The protease activity, which is increased by testosterone, is also increased to a lesser degree by the subcutaneous administration of spermidine. The administration of putrescine was less effective than that of spermidine. The increase of polyamine contents in the submaxillary gland of the castrated rats administered either testosterone or spermidine was nearly parallel to the increase of the enzymatic activity. The administration of methylglyoxal bis(guanylhydrazone), a potent inhibitor of spermidine synthesis, with testosterone inhibited slightly the increase of the protease activity by testosterone, while the administration of the inhibitor with spermidine had essentially no effect on the increase of the enzymatic activity by spermidine. The administration of testosteorne also caused a slight increase of S-adenosyl-L-menthionine decarboxylase activity. These results suggest that spermidine synthesis may be necessary for the stimulation by testosterone of protease synthesis in the rat submaxillary gland.

Follistatin and activin in bone: expression and localization during endochondral bone development.

The involvement of activin and follistatin, an activin-binding protein, in endochondral bone development was examined by sc implantation of demineralized bone matrix in rats. Immunoreactive follistatin was localized in proliferating chondrocytes and round osteoblasts, whereas it was not detected in hypertrophic chondrocytes and osteoblasts surrounding bone marrow. Western blot analysis also revealed that immunoreactive follistatin was higher during the initial stages of chondrogenesis (day 5) and osteogenesis (days 11 and 14) and lower during the conversion from cartilage to bone (day 9). These results suggest that follistatin is produced by proliferating cells, and the expression decreases with differentiation of the cells. Implants injected with follistatin on days 9 and 10 contained lower calcium levels on day 14 than those injected with rat albumin. Furthermore, the follistatin-injected implants were still mainly composed of cartilage, suggesting that the disappearance of follistatin is necessary for the conversion of cartilage to bone. In contrast, immunoreactive activin beta A (55-60 kDa) was continuously detected in implants on days 7-14. The content of C propeptide of type II procollagen was increased and cartilageous area was enlarged on day 7 by activin A injections on days 5 and 6, suggesting a chondrogenic effect of activin in the initial stage of cartilage formation. These results indicate that proliferating chondrocytes and round osteoblasts produce follistatin, and that the activity of activin is regulated by changes in the expression of follistatin at the stages of chondrogenesis and transition from cartilage to bone.

Immunolocalization of type I or type II activin receptors in the rat brain.

We have studied immunolocalization of activin receptors in the central nervous system using polyclonal antibodies (IgG) to type I (50-55 kDa, ActRI), type II (70-75 kDa, ActRII) or a subtype of type II known as type IIB (ActRIIB) receptors of activin. A total of 7 antisera to rat activin receptors was generated, i.e. 3 kinds of antisera to the extracellular domain (ActRI(81-89), ActRII(91-100), or ActRIIB(90-99)) and 4 antisera to the kinase domain (ActRI(323-333), ActRII(307-319), ActRII(407-420) or ActRIIB(306-319)). The region of aa 407-420 of ActRII is identical with that of ActRIIB. At first, we characterized these antibodies by Western blot analysis using ovarian proteins fractionated by preparative SDS-PAGE. All antibodies to ActRII and ActRIIB specifically reacted with 75 kDa-proteins which could also bind to activin-A. Anti-ActRII(91-100) antibody also reacted with 62 kDa-proteins which were capable of binding with activin-A. Although no positive reactions to anti-ActRI(81-89) antibody were seen in ovarian proteins, a positive reaction was detected at 52 kDa only when the proteins were deglycosylated. By use of these antibodies, immunolocalization of activin receptors was examined in the rat brain. The patterns of expression of activin type I and type II receptors were different. Positive reactions to anti-ActRII(91-100) antibody were detected in neurons of the cerebral cortex, hippocampus, medial amygdala and thalamus. In the hypothalamus, some neurons of the supraoptic nucleus were weakly stained, and widely scattered neurons of the lateral hypothalamic area were moderately stained. On the contrary, the most intense reactions to anti-ActRI(81-89) antibody were detected in neurons of the lateral hypothalamic area. In addition, many neurons of the cerebral cortex were also stained, but neurons of the hippocampus and the amygdala were not stained. These results suggest that activin may have physiological roles not only for hypothalamic neuroendocrinological and feeding-related systems as suggested previously but may also have functions in cortical and limbic pathways as a neuromodulator or for maintenance of neurons.

Immunological localization and ontogenetic development of inhibin alpha subunit in rat brain.

This study examined the immunolocalization and ontogeny of the inhibin-specific alpha subunit in the brain of male rats. Immunohistochemistry using antiserum directed against the mature region of porcine inhibin alpha (1-19, Tyr20) revealed positive reactions in process-bearing cells resembling astroglia in several regions, especially in the dorsal region of the third ventricle, medial and ventral arcuate nucleus, hippocampal dentate gyrus, and layers 1-3 of the cerebral cortex. Generally, inhibin alpha-positive cells in the limbic cortex had larger cell bodies and longer processes than those in the hypothalamus. These inhibin alpha-positive cells were verified to be positive for glial fibrillary acidic protein (GFAP), a differentiated astroglial marker, by double immunolabelling. The expression of inhibin alpha mRNA was higher in the brains of neonatal rats than in those of adult rats, as revealed by reverse transcription-competitive polymerase chain reaction, although the similar changes of immunoreactive inhibin alpha subunit in the brain was not observed. Orchiectomy did not affect expression of inhibin alpha mRNA in the hypothalamic area. This study suggests that inhibin-related peptide is produced by differentiated astrocytes, especially in the hypothalamic arcuate nucleus, the hippocampal dentate gyrus, and the cerebral cortex, and that the expression of inhibin alpha is regulated during brain development.

Slippage of nonsuperfluid helium films

We measured the mechanical response of 3He and 4He films on an oscillating substrate using an ultrasonic technique. Up to the coverage at which the fluid state appears at absolute zero, a part of the nonsuperfluid 3He and 4He films underwent slipping relative to the substrate at low temperatures. From the temperature dependence of the slippage, it was found that a thermally activated process plays an important role in the frictional force of this system.

Increased histidine preference during specific alteration of rhythm of environmental temperature stress in rats.

It has been reported that specific alteration of rhythm of environmental temperature (SART) stress induces various physiological changes. In this study, changes in taste preference during SART stress were investigated in rats. Rats were given free access to six amino acid solutions, saline, and water in a choice paradigm. During SART stress, daily food intake increased significantly by 50% whereas the rate of body weight gain decreased significantly to one third that observed during the prestress baseline period. In addition, consumption of histidine solution increased significantly, whereas intakes of water, monosodium glutamate, saline, glycine, arginine, lysine, and threonine were unaffected. Results suggest that a specific preference for histidine emerges during SART stress, which may be related to the stress-induced changes in the histamine turnover in the brain and peripheral tissues.

Crystal structure of monoclinic ribonuclease-S at 4 A resolution. The mode of binding of 4-thiouridylic acid and a fragment of folic acid, p-aminobenzoylglutamic acid.

A four-A electron density map was calculated for the monoclinic crystal of ribonuclease-S (RNase-S) based on two heavy-atom derivatives. Close geometrical similarity was found between the two crystallographically independent RNase-S molecules (called molecules ZA and ZB) in this crystal and that (called molecule Y) in the trigonal crystal. Using the rotational and translational parameters relating these three molecules, it was established that the crystallographic two-fold symmetry between the two molecules ZA in the monoclinic crystal was exactly identical to that between the two molecules Y in the trigonal crystal, suggesting the tendency of RNase-S molecules to associate in this way although the interaction is weak. The 4-A difference Fourier maps calculated for the monoclinic crystal established the following conclusions. (1) 4-Thiouridine-2'(3')-monophosphates binds to the B1 and R1 sites like other pyrimidine nucleoside-2'(3')-monophosphates as expected from previous spectrophotometric studies, but not to the B2 site even at the concentration of 20 mM. An attempt to visualize the photoproduct generated by irradiation of near-ultraviolet light in this complex failed. (2) p-Aminobenzoylglutamic acid, a fragment of folic acid, seems to bind to RNase-S with its benzene ring close to the B2 site and the alpha-carboxylate group close to the p1 site. The model is compatible with most of the chemical results obtained by Sawada et al. ((1977) Biochim. Biophys. Acta 479, 188-197).

Properties of Aspergillus niger catalase.

Catalase from Aspergillus niger was purified to homogeneity as judged from the results of ultracentrifugation and polyacrylamide gel electrophoresis. The enzyme had a molecular weight of 385,000 as estimated from sedimentation measurements. Carbohydrate analyses showed that the catalase was a glycoprotein containing about 8.3% neutral sugar and 1.9% glucosamine. Under denaturing conditions, polyacrylamide gel electrophoresis revealed only one band with a molecular weight of 97,000 daltons in gels stained for either protein or sugar, suggesting that the native enzyme consists of four subunits with covalently bound carbohydrate. In the reaction with inhibitors, A. niger catalase showed lower affinity than the "standard" catalases. The pK values for HCN, HN3, and HF were estimated to be 3.4 (at pH 7.4), 2.3, and 1.5 (at pH 4.2), respectively. In addition, the fungal enzyme reacts with methyl hydrogen peroxide in a very unusual way. Even after the addition of a large excess of the peroxide, only catalase compound I was formed, and compound II did not appear. Using this unique property of A. niger catalase, we obtained CD and MCD spectra of compound I uncontaminated by compound II. The magnitude of the positive CD peak of compound I in the Soret region was about half that of the native enzyme. The MCD spectrum obtained was better resolved than that of bovine liver catalase compound I in the visible region.

Unique recognition of activin and inhibin by polyclonal antibodies to inhibin subunits.

Inhibin-A is a glycoprotein composed of an alpha subunit containing a glycosylation site and a beta A subunit, whereas activin-A is a homodimer of two inhibin beta A subunits. We examined the recognition of activin-A and inhibin-A by several antisera to the alpha or beta A subunit, and factors affecting the recognition. A total of six polyclonal antibodies to inhibin subunits, i.e., two antisera to a peptide fragment of the alpha subunit [alpha (1-19) and alpha (1-26)], and four antisera to the beta A subunit [beta A (1-10), beta A (70-79), beta A (87-99), and beta A (94-105)], was generated. On Western blot analysis, the anti-beta A (87-99) and beta A (94-105) sera recognized recombinant human activin-A but not inhibin-A under non-reducing conditions. When inhibin-A was deglycosylated with N-glycosidase-F, inhibin-A could be recognized by the anti-beta A (87-99) and beta A (94-105) sera. In addition, when activin-A bound to a nitrocellulose membrane was pre-incubated with recombinant human follistatin, the recognition of activin-A by the anti- beta A (87-99) and beta A (94-105) sera was decreased. These results suggested that the lower affinity of follistatin to inhibin-A than to activin-A might be likely explained as reflecting a site associated with the glycosylation of inhibin-A. However, the exposure of amino acids 87-105 of the inhibin beta A subunit on the molecular surface through deglycosylation did not increase the affinity of inhibin-A for follistatin but rather resulted in poor binding with follistatin. The present data suggest that (1) amino acids 87-105 of the inhibin/activin beta A subunit are located on the molecular surface, although this region of inhibin-A is concealed by the carbohydrate chain of the alpha subunit, (2) the region responsible for follistatin binding within the activin beta A subunit is spanned by amino acids 87-105, and (3) the mode of binding of inhibin-A to follistatin is quite different from that of activin-A to follistatin, and the former may be influenced by glycosylation.

Hypothalamic control of amino acid appetite.

Preference for umami taste materials, such as monosodium L-glutamate (MSG) and the 5'-ribonucleotides, inosine 5'-monophosphate (IMP) and guanosine 5'-monophosphate (GMP), varies as a consequence of protein nutrition. Rats fed diets deficient in dietary protein or an essential L-amino acid (AA), L-lysine (Lys), avidly consumed Lys, glycine and NaCl but not umami substances. However, when the rats' protein nutrition was normal or when they were recovering from deficiency, a preference for umami substances was evident. These data suggest that the central mechanism for recognition of protein malnutrition may be coupled with umami taste preference. To test this, Lys-deficient and normal rats were employed as a model for taste preference changes. AA levels in plasma and brain remain essentially unchanged throughout the day while the rat is on standard chow but are altered during Lys deficiency. The recognition site for the deficit in the rats' brains was localized to the ventromedial (VMH) and lateral (LHA) hypothalamus as determined by functional magnetic resonance imaging (fMRI, 4.7 Telsa). Studies of single neuron activity in the LHA of Lys-deficient rats suggested that neuronal plasticity occurred. Following Lys deficiency, cells responded specifically to Lys, both iontophoretically applied and during ingestion of AA. Other LHA neurons of nondeficient rats differentially responded to MSG. The present results suggest that the LHA and probably the VMH play important roles in recognition of deficient nutrients. Neural plasticity of hypothalamic cells helps maintain AA homeostasis. Furthermore, a preference for umami substances may be an indicator that the organism (rat or human) is free of protein malnutrition.

Brief exposure to NaCl during early postnatal development enhances adult intake of sweet and salty compounds.

Taste acceptance involves both innate and acquired components. We observed an increased acceptance of salty and sweet solutions in adult rats whose tongues had been exposed to an NaCl-enriched milk formula during one day of early postnatal development. This behavioral effect was associated with changes in the norepinephrine system of the basolateral amygdala. No other changes in behavior, food intake, body weight, blood or metabolic parameters of the NaCl-exposed adult rats were identified. The data suggest a causal relationship between NaCl taste exposure, low content of amygdala norepinephrine cells and enhanced intake of sweet and salty compounds by adult rats. They also raise the question of the extent to which similar phenomena may occur during early human infant feeding.

Coexisting thymic carcinoid tumor and thymoma.

Thymic carcinoid tumors are unusual neoplasms that are different from thymomas. We report a case of coexisting thymic carcinoid tumor and thymoma associated with myasthenia gravis. The clinicopathological findings are discussed with a review of the literature.