Co-existence of alternative forms of 8q gain in cytogenetic clones of three patients with acute myeloid leukemia, pointing to 8q22 approximately 8qter as a region of biologic significance

Clonal trisomy 8 chromosome abnormalities can be detected in 15% of patients with acute myeloid leukemia (AML). The most common form of change is complete gain of the whole chromosome 8, followed by partial gains in unbalanced forms. The biologic consequences of trisomy 8 remain unclear, but a gene dosage effect is suspected. We report on three patients with AML who had alternative forms of chromosome 8 gain in their bone marrow cells. The partial gains resulted from a breakpoint in the chromosome band 8q22. This indicates that the region 8q22 to 8qter may be of particular pathogenetic importance.

Amorphous structures in the immiscible Ag-Ni system

Vapor quenching in the phase-separating Ag-Ni system creates alloys that appear homogeneously amorphous under conventional probes. However, an atomic-level structural analysis based on extended x-ray absorption fine structures in combination with reverse Monte Carlo and molecular dynamics simulations demonstrates that these new phases are characterized by nonuniform, spinodal-like structures on an extremely fine scale. This heterogeneous nature of the structure is directly responsible for the unexpectedly low heat (and temperature) of crystallization observed in calorimetric measurements.

Naturally small seesaw neutrino mass with no new physics beyond the TeV scale

If there is no new physics beyond the TeV energy scale, such as in a theory of large extra dimensions, the smallness of the seesaw neutrino mass, i.e., m(nu) = m(2)(D)/m(N), cannot be explained by a very large m(N). In contrast to previous attempts to find an alternative mechanism for a small m(nu), I show how a solution may be obtained in a simple extension of the standard model, without using any ingredient supplied by the large extra dimensions. It is also experimentally testable at future accelerators.

Mutation in pre-mRNA adenosine deaminase markedly attenuates neuronal tolerance to O2 deprivation in Drosophila melanogaster

O2 deprivation can produce many devastating clinical conditions such as myocardial infarct and stroke. The molecular mechanisms underlying the inherent tissue susceptibility or tolerance to O2 lack are, however, not well defined. Since the fruit fly, Drosophila melanogaster, is extraordinarily tolerant to O2 deprivation, we have performed a genetic screen in the Drosophila to search for loss-of-function mutants that are sensitive to low O2. Here we report on the genetic and molecular characterization of one of the genes identified from this screen, named hypnos-2. This gene encodes a Drosophila pre-mRNA adenosine deaminase (dADAR) and is expressed almost exclusively in the adult central nervous system. Disruption of the dADAR gene results in totally unedited sodium (Para), calcium (Dmca1A), and chloride (DrosGluCl-alpha) channels, a very prolonged recovery from anoxic stupor, a vulnerability to heat shock and increased O2 demands, and neuronal degeneration in aged flies. These data clearly demonstrate that, through the editing of ion channels as targets, dADAR, for which there are mammalian homologues, is essential for adaptation to altered environmental stresses such as O2 deprivation and for the prevention of premature neuronal degeneration.

Verifiable model of neutrino masses from large extra dimensions

We propose a new scenario of neutrino masses with a Higgs triplet (xi(++),xi(+),xi(0)) in a theory of large extra dimensions. Lepton number violation in a distant brane acts as the source of a very small trilinear coupling of xi to the standard Higgs doublet in our brane. Small realistic Majorana neutrino masses are naturally obtained with the fundamental scale M(*) approximately O(1) TeV, foretelling the possible discovery of xi (m(xi) less, similarM(*)) at future colliders. Decays of xi(++) into same-sign dileptons are fixed by the neutrino mass matrix. Observation of &mgr;-e conversion in nuclei is predicted.

[Effect of serum and wound exudates on PMN apoptosis in burned patients]

OBJECTIVE

To study in vitro the effect of burn serum and wound exudates on PMN apoptosis in burned patients.

METHODS

The burn serum was obtained from patients within 3 days postburn. The blister fluid was collected from intact blisters in burn wound within 24 hours postburn, and subeschar tissue fluid underneath III degree burn wound during escharectomy. PMNs were isolated from healthy human donors and cultured for 24 hours at 37 degreeC and 5% CO(2) with normal serum (NS), burn serum (BS), burn blister fluid (BBF) and subeschar tissue fluid (STF), respectively. Morphological assessment and quantification of PMN apoptosis were performed with AO + EB stain and flow cytometric analysis.

RESULTS

The number of apoptotic PMN and DNA fragmentation of PMN significantly decreased (P < 0.05) when PMN were cultured with BS, BBF, and STF when compared with that with NS. In addition, the specific DNA "ladder" pattern for apoptotic cells couldn't be found on the agarose gel electrophoresis in this case. However, BBF exhibited weaker inhibiting effect than BS and STF on PMN apoptosis.

CONCLUSION

PMN apoptosis could be inhibited in vitro by BS, STF and BBF from burned patients.

[The relationship between immunosuppression and oxygen free radicals in burned patients]

The serum immunosuppression effect and its relation to oxygen free radicals were studied in patients with thermal injury (n = 11, total body surface area 20%-83%). The serum MDA, sIL-2R increased significantly in burned patients (P < 0.01 all). The serum of burned patients depressed the IL-2 productin of normal human PBMC (P < 0.01). Antioxidants decreased the serum sIL-2R in burned patients and attenuated the suppressive effect IL-2 production of normal human PBMC (P < 0.05 all). The results suggest that oxygen free radicals participate in the serum immunosuppression effect in burned patients.

[Changes of PMN apoptosis in rabbits after burn]

OBJECTIVES

To study the dynamic changes of apoptosis of PMN from rabbits in the early stage after severe burn in vivo and investigate the effect of burn serum and wound exudate on PMN apoptosis in vitro.

METHODS

12 rabbits were randomly divided into 2 groups: control group (37 degrees C) and burn group (95 degrees C, 15 sec, III degrees 30% TBSA). Whole blood from the burn group at 0, 4, 8, 12, 24 h postburn was stained with acridine orange/ethidium bromide (AO + EB), and observed under UV microscopy. PMNs were isolated from both groups and cultured for 24 h (37 degrees C, 5% CO(2)) with normal serum (NS), burn serum (BS), and subeschar tissue fluid (STF) respectively. Morphological assessment and quantitation of apoptosis were performed with AO + EB stain and flow cytometric analysis.

RESULTS

The number of apoptotic PMN in vivo decreased in the early stage postburn. In the BS + PMN group and STF + PMN group, the percentage of apoptotic PMN reduced (vs NS + PMN group, P < 0.05) and the specific DNA "ladder" pattern for apoptotic cells was not detected by agarose gel electrophoresis. We observed that both burn serum and STF could similarly suppressed PMN apoptosis while there was no significant difference between NS + normal PMN group and NS + burn PMN group.

CONCLUSIONS

Apoptosis is inhibited in PMN from rabbits postburn in the early stage. Both burn serum and STF from rabbits postburn can inhibit PMN apoptosis in vitro.

Isolation and characterization of the hypoxia-inducible factor 1beta in Drosophila melanogaster

The hypoxia-inducible factor 1 (HIF-1), a heterodimer composed of alpha and beta subunits, plays an important role in the cellular response to O(2) deprivation. In this paper, Drosophila HIF-1beta (dHIF-1beta) homolog is cloned and characterized. Further, Northern analyses showed that dHIF-1alpha and dHIF-1beta expressed their highest level at an embryonic stage. From the pupal stage on, their expression was sharply reduced and maintained at a steady level. Anoxia treatment up-regulated the expression of the both alpha and beta subunits. Over-expression of dHIF-1alpha in transgenic embryos resulted in embryonic lethality, while over-expression of dHIF-1beta significantly prolonged fly recovery time from a 5-min anoxic stupor. The cloning and characterization dHIF-1beta reported in this paper provide a framework for further genetic dissection of the HIF-1 complex in its role in the cellular or tissue response to O(2) deprivation.

Developmental changes in leg coordination of the chick at embryonic days 9, 11, and 13: uncoupling of ankle movements

To understand changes in motor behavior during development, kinematic measurements were made of the right leg during embryonic motility in chicks on embryonic (E) days 9, 11, and 13. This is an interesting developmental period during which the embryo first becomes large enough to be physically constrained by the shell. Additionally, sensory systems are incorporated at that time into the spinal motor circuitry. Previous electromyographic (EMG) recordings have shown that the basic pattern of muscle activity seen at E9, composed of half-center-type alternation of extensor and flexor activation, breaks down by E13. This breakdown in organization could be because of disruption of motor patterns by the immature sensory system and/or new spatial constraints on the embryo. The current article describes several changes in leg movement patterns during this period. Episodes of motility increase in duration and the intervals of time between episodes of motility decrease in length. The range of motion of the leg increases, but the overall posture of the leg becomes more flexed. It was found that in-phase coordination of movement among the hip, knee, and ankle decreased between E9 and E13 in agreement with the previous EMG recordings. However, it was also found that the decrease of in-phase coordination among the three joints was accompanied by an increase in the time any two joints were moving in the same manner. Furthermore, examination of in-phase coordination within pairs of joints showed that all three pairs were well coordinated at E9, but that at E13 the in-phase coordination of the ankle with the other two joints decreased, whereas the knee and hip coordination was maintained. This suggests that the hip-knee synergy was closely coupled and that coupling of the ankle with other joints was more labile. The authors conclude that embryos respond to the reduction of free space in the egg during this period not by decreasing the amplitude or coordination of leg movements in general, but instead by differentially controlling the movements of the ankle from those of the hip and knee. Additionally, the changes in movement patterns do not represent a decrease in organization, but rather an alteration of motor coordination possibly as the result of information from the newly acquired sensory systems. These data also support theories that limb central pattern generators (CPGs) are composed of unit CPGs for each joint that can be modulated individually and that this organization is already established early in embryogenesis.

Intracellular pH regulation of CA1 neurons in Na(+)/H(+) isoform 1 mutant mice

To understand the role of Na(+)/H(+) exchanger 1 (NHE1) in intracellular pH (pH(i)) regulation and neuronal function, we took advantage of natural knockout mice lacking NHE1, the most ubiquitously and densely expressed NHE isoform in the central nervous system (CNS). CA1 neurons from both wild-type (WT) and NHE1 mutant mice were studied by continuous monitoring of pH(i), using the fluorescent indicator carboxy-seminaphthorhodafluor-1 (SNARF-1) and confocal microscopy. In the nominal absence of CO(2)/HCO(3)(-), steady-state pH(i) was higher in WT neurons than in mutant neurons. Using the NH(4)Cl prepulse technique, we also show that H(+) flux in WT neurons was much greater than in mutant neurons. The recovery from acid load was blocked in WT neurons, but not in mutant neurons, by removal of Na(+) from the extracellular solution or by using 100 microM 3-(methylsulfonyl-4-piperidino-benzoyl)-guanidine methanesulfonate (HOE 694) in HEPES buffer. Surprisingly, in the presence of CO(2)/HCO(3)(-), the difference in H(+) flux between WT and mutant mice was even more exaggerated, with a difference of more than 250 microM/s between them at pH 6.6. H(+) flux in CO(2)/HCO(3)(-) was responsive to diisothiocyanato-stilbene-2, 2'-disulfonate (DIDS) in the WT but not in the mutant. We conclude that (a) the absence of NHE1 in the mutant neurons tended to cause lower steady-state pH(i) and, perhaps more importantly, markedly reduced the rate of recovery from an acid load; and (b) this difference in the rate of recovery between mutant and WT neurons was surprisingly larger in the presence, rather than in the absence, of HCO(3)(-), indicating that the presence of NHE1 is essential for the regulation and/or functional expression of both HCO(3)(-)-dependent and -independent transporters in neurons.

A Drosophila CDK5alpha-like molecule and its possible role in response to O(2) deprivation

Cyclin-dependent kinase 5 activator (Cdk5alpha) is an activator of Cdk5 kinase activity and its expression is restricted to neurons. The complex of Ckd5/Cdk5alpha is essential for neurite outgrowth during neuronal differentiation and possibly also for neuronal degeneration. Here we report the isolation and characterization of a Drosophila Cdk5alpha-like molecule (dCdk5alpha). The gene encoding this molecule is localized in the Drosophila chromosome region of 31D1-31D2. The expression of this gene is differentially regulated with a very low level at earlier developmental stages and reaches the highest level in the adult. The C-terminal of this molecule shares high homology with the mammalian Cdk5alpha molecule. Constitutive over-expression of dCdk5alpha in transgenic flies significantly prolongs their recovery time from 5 min to O(2) deprivation or anoxia in older flies (15 days) but not in young ones (4 days). In addition, anoxia up-regulated the expression of this gene. Taken together, the results in this report and others provide a framework for genetically dissecting the functions of Cdk5alpha/Cdk5 complex in the CNS.

Maturation of medial efferent system function in humans

Otoacoustic emissions are typically reduced in amplitude when broadband noise is presented to the contralateral ear. This contralateral suppression is attributed to activation of the medial olivocochlear system, which has an inhibitory effect on outer hair-cell activity. By studying the effects of contralateral noise on cochlear output at different stages of auditory maturation in human neonates, it is possible to describe the timecourse for development of medial efferent system function in humans. The present study recorded 2 f1-f2 distortion product otoacoustic emissions (DPOAE) in human adults, term and premature neonates at three f2 frequencies: 1500, 3000, and 6000 Hz, using fixed primary tone frequency ratio (f2/f1 = 1.2) and level separation (10 dB, L1 > L2). Average DPOAE growth functions were recorded with and without contralateral broadband noise. Results indicate that contralateral suppression of DPOAEs is absent at 6000 Hz, but present at 1500 and 3000 Hz for all ages. However, DPOAE amplitude from premature neonates was not altered by noise in an adult-like manner; in this age group, DPOAE amplitude was equally likely to by suppressed or enhanced by noise presented contralaterally. Contralateral enhancement may reflect a temporary stage of immaturity in outer hair cell-medial efferent fiber synapses just prior to term birth.

Gene regulation by O2 deprivation: an anoxia-regulated novel gene in Drosophila melanogaster

Organisms, across the animal kingdom, vary in their tolerance or susceptibility to cell injury from O2 deprivation. In this study we have taken advantage of the genetically well studied fruit fly to dissect basic mechanisms underlying their ability to tolerate lack of O2. Using differential display and molecular techniques, we cloned and characterized a novel gene, named fau, which is up-regulated considerably following anoxia in Drosophila melanogaster. Northern blot analysis revealed that the transcript of this gene is approximately 0.9 kb in length with an open reading frame encoding a small hydrophilic protein ( approximately 14.4 kDa). This protein has no homology to previously described gene products but has many potential phosphorylation sites. In situ hybridization showed that this gene is located in region 7C-D on the Drosophila X-chromosome and its transcript concentrated in the lamina and cortical neurons of the Drosophila central nervous system (CNS). Transgenic flies showed that over-expression of fau significantly reduced the recovery time of the flies from anoxia. We conclude that (1) this study provided a framework on which the mechanisms underlying anoxia tolerance can be dissected in the fruit fly and (2) fau gene plays an important role in the regulation of tissue responsiveness to O2 deprivation.

[The protective effect of SOD on injury of bone marrow hematopoietic progenitor cells of mice under 4 degrees C storage]

The protective effect of Cu, Zn, SOD on bone marrow hematopoietic progenitor cells of mice, under 4 degrees C storage was studied. The results showed, if 1.65 U or 0.165 U/ml SOD was added to the cell suspension for 3 days at 4 degrees C, the production rate of CFU-GM, CFU-E, BFU-E, CFU-Meg and CFU-Mix were 6.2, 2.6, 2.9, 4.0 and 5.1 times that of control group (without SOD) respectively. The survival rate of hematopoietic progenitor cells increased obviously. The mechanism of SOD effect is supposed to prevent hematopoietic progenitor cells from death, instead of the regulating proliferation. It may be closely related to the antioxidation of SOD which scavenges the superoxide free radicals.

Expression and localization of Na+/H+ exchangers in rat central nervous system

Neurons in the central nervous system regulate their intracellular pH using particular membrane proteins of which two, namely the Na+-dependent Cl-/HCO3- exchanger and the Na+/H+ exchanger, are essential. In this study we examined messenger RNA expression and distribution of Na+/H+ exchanger in the newborn rat central nervous system and with maturation using Northern blot analysis and in situ hybridization. Our study clearly shows that each Na+/H+ exchanger has a different expression pattern in the rat central nervous system. As in non-excitable tissues, Na+/H+ exchanger 1 is by far the most abundant of all Na+/H+ exchangers in the rat central nervous system. Its expression is ubiquitous although its messenger RNA appears at higher levels in the hippocampus, in the 2nd/3rd layers of periamygdaloid cortex and in the cerebellum. The low level of messenger RNAs encoding Na+/H+ exchanger 2 and 4 is mainly expressed in the cerebral cortex and in the brainstem-diencephalon, while Na+/H+ exchanger 3 transcripts are found only in the cerebellar Purkinje cells. From a developmental point of view, Na+/H+ exchanger 1, 2 and 4 showed an increased level in their transcripts in the cerebral cortex while an opposite trend existed in the cerebellum from postnatal day 0 to postnatal day 30. The messenger RNA for Na+/H+ exchanger 3, however, increased its level with age in cerebellum. From our data we conclude that: i) the expression of the Na+/H+ exchanger is age-, region-, and subtype-specific, with Na+/H+ exchanger 1 being the most prevalent in the rat central nervous system; ii) specialization of groups of neurons with respect to the type of Na+/H+ exchanger is clearly illustrated by Na+/H+ exchanger 3 which is almost totally localized in cerebellar Purkinje cells; and iii) the developmental increase in the messenger RNA for Na+/H+ exchanger 1 in the cerebral cortex and hippocampus is consistent with our previous studies on intracellular pH physiology in neonatal and mature neurons. Together this study indicates that expression of each Na+/H+ exchanger messenger RNA is differentially regulated both during development and in the different regions of rat central nervous system.

Anoxia regulates gene expression in the central nervous system of Drosophila melanogaster

We took advantage of the Drosophila melanogaster's extraordinary resistance to anoxia to study the molecular mechanisms underlying this phenomenon. We analyzed mRNA expression of heat shock proteins (HSP) (HSP26 and HSP70), ubiquitins (UB) (UB3 and UB4), cytochrome oxidase I (COXI) and superoxide dismutase (SOD) using slot blot analysis. The expression of HSP genes, especially HSP70, was remarkably up-regulated (up to a thousand-fold) while those of UB4 and COXI were down-regulated (10-60%) in response to the anoxic stress. The expression of UB3 gene was up-regulated by 1.5x and the expression of SOD gene was not significantly affected. In response to heat shock stress, the expression of HSP genes increased by up to several thousand-fold, the expression of UB genes increased modestly (23-91%) but the expression of SOD and COXI genes was reduced by 25%. Furthermore, the expression patterns of HSP genes under anoxia and heat shock were clearly different. The expression of HSP genes peaked by 15 min into anoxia and then declined but stayed above baseline. In contrast, their expression increased as a function of time during heat exposure. From these results, we conclude that: (1) different forms of stress regulates gene expression in different ways; (2) anoxia differentially regulates gene expression; and (3) the up-regulation of HSP70 and down-regulation of UB4 by anoxia are consistent with the idea that Drosophila melanogaster resist anoxia, at least in part, by protecting proteins against degradation.

Effect of stimulus level and frequency on ABR and MLR binaural interaction in human neonates

Auditory brainstem (ABR) and middle latency (MLR) responses were evoked by click and tone-burst stimuli from human neonates. Electrophysiologic evidence of binaural interaction was measured by subtracting waveforms obtained for binaural stimulus conditions from waveforms obtained for the sum of right ear monaural and left ear monaural stimulus conditions. The effects of stimulus level and stimulus frequency on binaural interaction were evaluated by measuring the number, latency and amplitude of components found in the derived binaural interaction waveform, that is, binaural interaction components (BIC). BICs were more prevalent in the latency range of ABRs than for MLRs. Click and tonal stimuli were equally effective for deriving ABR-BICs, while tone-bursts were somewhat less effective than clicks for deriving MLR-BICs. Stimulus-response dependencies for ABR and MLR component latencies were apparent in monaural, binaural and binaural interaction waveforms. Normalized amplitudes for BICs showed that low-frequency tone-burst stimuli resulted in the largest values compared to click and high-frequency tonal stimuli. Comparison of these results with published results from adults demonstrated immaturity of binaural interaction in neonates.

Expression of GH, TSH beta, LH beta and FSH beta genes during fetal pituitary development in the pig

The development of the anterior pituitary gland involves the proliferation and differentiation of ectodermal cells in Rathke's pouch to generate distinct cell types, each of which produces its corresponding trophic hormone. Studying pituitary development will therefore reveal novel aspects of organogenesis. In the present study, we examined by in situ hybridization the expression of genes for anterior pituitary hormones during development of the fetal pig pituitary. We found that the beta-subunit gene of thyroid-stimulating hormone (TSH beta) was first expressed at E40, (E = day of embryonal/fetal life), growth hormone (GH) mRNA appeared between E40 and E50, and the gonadotrophin genes (LH beta and FSH beta) were expressed at E50. The transcripts for TSH beta, LH beta and FSH beta were abundantly expressed at about E80, while GH mRNA continued to be richly expressed until after birth. The GH gene was first expressed in the mantle layer of the anterior lobe, while the TSH beta and gonadotrophin (LH beta and FSH beta) mRNAs were found in the central and the basal regions of the anterior lobe, respectively. All of these mRNAs (GH, TSH beta, LH beta, and FSH beta) remained concentrated until the end of gestation in the area where they first appeared. The distinctive pattern of developmental expression of these hormone genes in the fetal pig anterior pituitary makes this tissue an excellent system in which to study tissue-specific gene activation and regulation.