UCHL1 Impairs Periodontal Ligament Stem Cell Osteogenesis in Periodontitis

Periodontitis comprises a series of inflammatory responses resulting in alveolar bone loss. The suppression of osteogenesis of periodontal ligament stem cells (PDLSCs) by inflammation is responsible for impaired alveolar bone regeneration, which remains an ongoing challenge for periodontitis therapy. Ubiquitin C-terminal hydrolase L1 (UCHL1) belongs to the family of deubiquitinating enzymes, which was found to play roles in inflammation previously. In this study, the upregulation of UCHL1 was identified in inflamed PDLSCs isolated from periodontitis patients and in healthy PDLSCs treated with tumor necrosis factor-α or interleukin-1β, and the higher expression level of UCHL1 was accompanied with the impaired osteogenesis of PDLSCs. Then UCHL1 was inhibited in PDLSCs using the lentivirus or inhibitor, and the osteogenesis of PDLSCs suppressed by inflammation was rescued by UCHL1 inhibition. Mechanistically, the negative effect of UCHL1 on the osteogenesis of PDLSCs was attributable to its negative regulation of mitophagy-dependent bone morphogenetic protein 2/Smad signaling pathway in periodontitis-associated inflammation. Furthermore, a ligature-induced murine periodontitis model was established, and the specific inhibitor of UCHL1 was administrated to periodontitis mice. The histological results showed increased active osteoblasts on alveolar bone surface and enhanced alveolar bone regeneration when UCHL1 was inhibited in periodontitis mice. Besides, the therapeutic effects of UCHL1 inhibition on ameliorating periodontitis were verified, as indicated by less bone loss and reduced inflammation. Altogether, our study proved UCHL1 to be a key negative regulator of the osteogenesis of PDLSCs in periodontitis and suggested that UCHL1 inhibition holds promise for alveolar bone regeneration in periodontitis treatment.

Buffering Octahedra in Mo4Zr9P: Intergrowth as a Solution to the Frustrated Packing of Tricapped Trigonal Prisms and Icosahedra

Atomic packings based on icosahedra and tricapped trigonal prisms are prone to frustration─indeed, these polyhedra represent common configurations in metallic glasses. In this Article, we illustrate how these packing issues can serve as a driving force for the formation of modular intermetallic structures. Using Density Functional Theory-Chemical Pressure (DFT-CP) analysis, we relate the Hf₉Mo₄B-type structure of Mo₄Zr₉P to interatomic pressures experienced by the atoms in two parent structures: Zr₃P, whose structure is built from tricapped trigonal prisms, and ZrMo₂, a Laves phase containing icosahedra. CP analysis of Zr₃P reveals that it has particularly frustrated packing because of the entangling of its tricapped trigonal prisms. In the ternary phase, the frustration is significantly relieved as the units become isolated from each other. Further analysis points to the stabilizing effect of a face-sharing network of octahedra in Mo₄Zr₉P that largely separates the structure into Zr-Mo and Zr-P domains and serves as a buffering region for the relaxation of interatomic distances. These conclusions are generalized to the broader members of this structure type with the examination of the CP schemes for the isostructural Mo₄Zr₉B, Al₅Co₂, and Mg₅Pd₂ phases. Finally, we screen the structural literature using the ToposPro software to identify three additional structure types that have similar intergrowth patterns: the Dy₄CoCd, La₂₃Ni₇Mg₄, and Gd₁₄Co₃In₃ types. An analysis of the interatomic distances within the octahedral networks of these structures suggests that these networks commonly facilitate the reconciliation of packing incompatibilities in intermetallic chemistry.

At the Limits of Isolobal Bonding: π-Based Covalent Magnetism in Mn2Hg5

Magnetic ordering in inorganic materials is generally considered to be a mechanism for structures to stabilize open shells of electrons. The intermetallic phase Mn₂Hg₅ represents a remarkable exception: its crystal structure is in accordance with the 18-n bonding scheme and non-spin-polarized density functional theory (DFT) calculations show a corresponding pseudogap near its Fermi energy. Nevertheless, it exhibits strong antiferromagnetic ordering virtually all the way up to its decomposition temperature. In this Article, we examine how these two features of Mn₂Hg₅ coexist through the development of a DFT implementation of the reversed approximation Molecular Orbital (raMO) analysis. In the non-spin-polarized electronic structure, the DFT-raMO approach confirms that Mn₂Hg₅ adheres to the 18-n rule: its chains of Mn atoms are linked through isolobal triple bonds, with three electron pairs being shared at each Mn-Mn contact in one σ-type and two π-type functions. Because each Mn atom has 6 isolobal Mn-Mn bonds, it achieves a filled 18-electron count at the compound's electron concentration of 18 - 6 = 12 electrons/Mn. A pseudogap thus occurs at the Fermi energy. Upon the introduction of antiferromagnetic order, the original pseudogap widens and deepens, suggesting enhancement of a stabilizing effect already present in the nonmagnetic state. A raMO analysis reveals that antiferromagnetism enlarges the gap by allowing diradical character to enter into the Mn-Mn isolobal π bonds, reminiscent of the dissociation of a classic covalent bond. Antiferromagnetism is accompanied by residual bonding in the π system, making Mn₂Hg₅ a vivid realization of the concept of covalent magnetism.

External beam for the Heavy Ion Accelerator Facility

Radiotherapy using protons and heavier ions is emerging as an alternative to traditional photon radiotherapy for cancer treatment. Ions have a depth-dose profile that results in high energy deposition at the end of the particle’s path, with a relatively low dosage elsewhere. However, the specifics of ion interactions with cellular biology are not yet fully understood. To study the induced biological effects of the ions on cell cultures, an external beam is required as biological specimens cannot be placed in vacuum. The Heavy Ion Accelerator Facility (HIAF) at the Australian National University hosts accelerators for a wide variety of ion-beam research applications. However, HIAF does not currently have an external beam capability. Here, we present an initial design for a radiobiological research capability at HIAF. A systems engineering approach was used to develop the architecture of the apparatus and determine the feasibility of adapting the current facilities to external beam applications. This effort included ion optics calculations, coupled to a Geant4 simulation, to characterise ion beam transitions through a thin window into the air. The beam spread, intensity distributions, and energy of proton and carbon ions were studied as a function of distance travelled from the window, as well as the effects of alternative window materials and thicknesses. It was determined that the proposed line at the HIAF would be suitable for the desired applications. Overall, this feasibility study lays the foundations of an external beam design, a simulation test framework, and the basis for a grant application for an external beam at the HIAF.

Templating Structural Progessions in Intermetallics: How Chemical Pressure Directs Helix Formation in the Nowotny Chimney Ladders

In the structural diversity of intermetallic phases, hierarchies can be perceived relating complex structures to relatively simple parent structures. One example is the Nowotny Chimney Ladder (NCL) series, a family of transition metal-main group (T-E) compounds in which the T sublattices trace out helical channels populated by E-atom helices. A sequence of structures emerges from this arrangement because the spacing along the channels of the E atoms smoothly varies relative to that of the T framework, dictated largely by optimization of the valence-electron concentration. In this Communication, we show how this behavior is anticipated and explained by the Density Functional Theory-Chemical Pressure (DFT-CP) schemes of the NCLs. A CP analysis of the RuGa₂ parent structure reveals CP quadrupoles on the Ga atoms (telltale signs of soft atomic motion) that arise from overly short Ru-Ga contacts along one axis and underutilized spaces in the perpendicular directions. In their placement and orientation, the CP quadrupoles highlight a helical path of facile movement for the Ga atoms that avoids further compression of the already strained Ru-Ga contacts. The E atoms of a series of NCLs (in their DFT-optimized geometries) are all found to lie along this helix, with the CP quadrupole character being a persistent feature. In this way, the T sublattice common to the NCLs encodes helical paths by which the E-atom spacing can be varied, creating a mechanism to accommodate electronically driven compositional changes. These results illustrate how CP schemes can be combined with electron-counting rules to create well-defined structural sequences, potentially guiding the discovery of new intermetallic phases.

Pseudogap Control of Physical and Chemical Properties in CeFeSi-Type Intermetallics

We describe the synthesis of the new ternary compound CaRuSi whose chemical and physical properties help draw a clear picture of how electronic structure controls the behavior of an isostructural series of intermetallics. DFT calculations reveal that an electronic pseudogap arises near the Fermi level ( E_F), corresponding to 14 valence electrons per RuSi unit. The closed-shell-like character is further investigated by comparisons with the electronic structures of CaCoSi (15 electrons), where the E_F lies above the corresponding pseudogap, and its hydride CaCoSiH, where formation of H anions restores the 14-electron count on the metal sublattice, returning the E_F to the pseudogap. The chemical origin of the 14-electron pseudogap is interpreted with a reversed approximation Molecular Orbital analysis. Here, the pseudogap is shown to coincide with the filling of Ru 16 electron configurations isolobal to the d⁸ square planar complexes of coordination chemistry (but where 4 electron pairs are shared covalently between Ru atoms such that only 12 electrons are required), and the occupation of Si lone pairs (2 electrons). Experimentally, the pseudogap is confirmed with heat capacity measurements, which indicate that the 14-electron systems CaRuSi and CaCoSiH each exhibit  a smaller electronic density of states at the E_F than the 15-electron system CaCoSi. Importantly, the 14-electron pseudogap also significantly affects the chemical properties of the compounds, as evidenced by the difference in the stabilities of CaCoSiH and CaRuSiH observed in hydrogen desorption measurements. These results may support the design of functional materials for superconductivity, hydrogen storage, and catalysis involving hydrogenation.

Birth outcomes of pregnancies fathered by men with multiple sclerosis

We linked several population-based clinical and health administrative databases in British Columbia, Canada. We identified and compared birth outcomes of pregnancies fathered by men with multiple sclerosis (MS) (n=202) and men from a frequency-matched general population cohort (n=981) between 1996 and 2010. Using multivariate models, we analyzed the association of paternal MS, disease duration at conception and disability (as measured by the Expanded Disability Status Scale) with birth weight and gestational age. Paternal MS and MS-related clinical factors were not significantly associated with birth outcomes (p>0.05). This study provides assurance to expecting fathers with MS and their families.

Pathway-based analysis of primary biliary cirrhosis genome-wide association studies

Genome-wide association studies (GWAS) have successfully identified several loci associated with primary biliary cirrhosis (PBC) risk. Pathway analysis complements conventional GWAS analysis. We applied the recently developed linear combination test for pathways to datasets drawn from independent PBC GWAS in Italian and Canadian subjects. Of the Kyoto Encyclopedia of Genes and Genomes and BioCarta pathways tested, 25 pathways in the Italian dataset (449 cases, 940 controls) and 26 pathways in the Canadian dataset (530 cases, 398 controls) were associated with PBC susceptibility (P<0.05). After correcting for multiple comparisons, only the eight most significant pathways in the Italian dataset had FDR <0.25 with tumor necrosis factor/stress-related signaling emerging as the top pathway (P=7.38 × 10⁻⁴, FDR=0.18). Two pathways, phosphatidylinositol signaling and hedgehog signaling, were replicated in both datasets (P<0.05), and subjected to two additional complementary pathway tests. Both pathway signals remained significant in the Italian dataset on modified gene set enrichment analysis (P<0.05). In both GWAS, variants nominally associated with PBC were significantly overrepresented in the phosphatidylinositol pathway (Fisher exact P<0.05). These results point to established and novel pathway-level associations with inherited predisposition to PBC that, on further independent replication and functional validation, may provide fresh insights into PBC etiology.

Labor induction and augmentation in women with multiple sclerosis

Background:

Fatigue and pelvic organ dysfunction are common among women with multiple sclerosis (MS), which may prolong labor and increase the risk of labor induction and/or augmentation.

Objective:

We set out to investigate the association between MS and related clinical factors (disease duration and the Expanded Disability Status Scale, EDSS) with labor induction/augmentation.

Methods:

Data from the British Columbia (BC) MS database were linked with the BC Perinatal Database Registry. Multivariable models were used to compare the likelihood of labor induction and augmentation between attempted vaginal deliveries (1998–2009) in women with MS ( n=381) and the general population ( n=2615).

Results:

In the MS cohort, 94/381 deliveries (25%) required labor induction and 147/381 deliveries (39%) required labor augmentation. Having MS was not associated with labor induction (adjusted odds ratio (OR)=0.91; 95% confidence interval (CI)=0.68–1.22, p=0.54) or augmentation (adjusted OR=0.91; 95% CI=0.72–1.15, p=0.43), but was associated with multiple methods of labor induction (OR=1.94; 95% CI=1.23–3.06, p=0.004). A higher EDSS score was associated with an increased risk of labor induction (adjusted p=0.04), but not labor augmentation (adjusted p > 0.5). Disease duration was not associated with either outcome (adjusted p > 0.2).

Conclusions:

Greater intervention may be required to initiate labor for women with a higher degree of disability due to MS.

Perinatal outcomes in women with multiple sclerosis exposed to disease-modifying drugs

Background: The incidence of disease-modifying drug (DMD) exposure during pregnancy in multiple sclerosis (MS) is unknown and limited data exists regarding the potential harm of DMD exposure during pregnancy.

Objective: To investigate the incidence and effect of in utero DMD exposure on perinatal outcomes.

Methods: We conducted a retrospective analysis by linking two provincial, population-based databases, the British Columbia (BC) MS database with the BC Perinatal Database Registry. Delivery (duration of the second stage of labor, assisted vaginal delivery and Cesarean section) and neonatal (birth weight, gestational age, 5-minute Apgar score and congenital anomalies) outcomes were compared between women exposed and unexposed to a DMD within 1 month prior to conception and/or during pregnancy. Findings were reported as odds ratios (ORs) with 95% confidence intervals (CIs).

Results: In all, 311 women with relapsing–remitting MS delivered 418 singleton babies between April 1998 and March 2009. 21/101 (21%) of births to MS women treated with DMD prior to pregnancy were exposed to a DMD. In all cases, exposure was documented as unintentional and DMD treatment was stopped within 2 months of gestation. The overall incidence of exposure was 21/418 (5%). DMD exposure was associated with a trend towards a greater risk of assisted vaginal delivery compared to the DMD naïve groups (OR = 3.0; 95% CI: 1.0–9.2). All other comparisons of perinatal outcomes were unremarkable.

Conclusion: The incidence of DMD exposure was relatively low and no cases were intentional. Further studies are needed to ascertain the safety of DMD exposure during pregnancy in MS.

[Biochemical changes in striatum of Parkinson's disease rat model observed by modified proton magnetic resonance spectroscopy]

This study was undertaken to observe the biochemical changes in striatum of Parkinson's disease (PD) rat model by modified proton magnetic resonance spectroscopy. 12 SD rats were divided into model (n=7) and control (n=5) groups. At 3 weeks after the injection of 6-hydroxydopamine into right striatum, 1H-MRS on the striatum was taken by modified proton magnetic resonance spectroscopy, and then tyrosine hydroxylase (TH) immunostatining was used to visualize the changes of the neurons in substantia nigra and neurites in striatum. The results showed that TH positive neurons and neurites in the substantia nigra compacts (SNc) and striatum in the normal side of the rat model of PD were decreased (P < 0.05), which proved the successful establishment of PD models. The NAA/Cr ratio of the injected side striatum of model group was lower than that of the normal side (P < 0.05). The ratios of Cho/Cr showed no significant difference between the two sides (P > 0.05). These results indicated that the modified 1.5T 1H-MRS should be a noninvasive technique which could provide useful information about the biochemical metabolites in striatum for the study of PD in rat model.

Different distributions of calbindin and calretinin immunostaining across the medial and dorsal divisions of the mouse medial geniculate body

We studied the distributions of calretinin and calbindin immunoreactivity in subdivisions of the mouse medial geniculate body and the adjacent paralaminar nuclei. We found that the vast majority of labeled cells in the dorsal division of the medial geniculate body were immunoreactive for calbindin-only, whereas most of the remaining labeled cells were double-labeled. Very few calretinin+ only cells were observed. By contrast, we observed significant proportions of calbindin+ only, calretinin+ only and double-labeled cells in the medial division of the medial geniculate body. Further, the distributions of calbindin-only, calretinin-only and double-labeled cells did not differ between the medial division of the medial geniculate body, the suprageniculate nucleus, the peripeduncular nucleus and the posterior intralaminar nucleus. We found essentially no somatic staining for either calbindin or calretinin in the ventral division of the medial geniculate body. These data suggest that there are distinct neurochemical differences between the two non-lemniscal auditory thalamic nuclei. In addition, these data extend previous observations that the medial division of the medial geniculate body shares many properties with the paralaminar group of nuclei.

[Investigation on the quality indicators of beers using NIR]

Near infrared spectroscopy (NIR) has been used to determine important indicators of the quality of undeaired beers by a partial least squares (PLS) regression and stepwise multiple linear regression (SMLR). The indicators are original, real extract and alcohol contents. Absorbance spectra in transmission mode of 83 samples were obtained with 1 mm and 5 mm path-length quartz cell. The selected resolving powers are 8, 16 and 32 cm(-1). Air and water were used as background respectively. It was concluded that the calibration and prediction results are similar with different background, pathlength and resolving power. The SMLR method seems to be better than PLS method. The results of this paper provide a foundation for the application and further development of NIR on-line beer analyzer.

Reconstruction control of magnetic properties during epitaxial growth of ferromagnetic Mn3-deltaGa on Wurtzite GaN(0001)

Binary ferromagnetic Mn(3-delta)Ga (1.2<3-delta< or =1.5) crystalline thin films have been epitaxially grown on wurtzite GaN(0001) surfaces using rf N-plasma molecular beam epitaxy. The film structure is face-centered tetragonal with CuAu type-I (L1(0)) ordering with (111) orientation. The in-plane epitaxial relationship to GaN is nearly ideal with [110](MnGa) parallel[1100](GaN) and [112](MnGa) parallel[1120](GaN). We observe magnetic anisotropy along both the in-plane and out-of-plane directions. The magnetic moments are found to depend on the Mn/(Mn+Ga) flux ratio and can be controlled by observation of the surface reconstruction during growth, which varies from 1x1 to 2x2 with increasing Mn stoichiometry.

Scanning tunneling microscopy and surface simulation of zinc-blende GaN(001) intrinsic 4x reconstruction: linear gallium tetramers?

Scanning tunneling microscopy images confirm electron diffraction studies that the zinc-blende GaN(001)-4x reconstruction consists of rows aligned along [110] with a spacing along [110] of 4a. Dual-bias imaging shows a 180 degree shift of the corrugation maximum position between the profiles of empty and occupied states, in agreement with surface simulations based on the 4 x 1 linear tetramer model of Neugebauer et al. [Phys. Rev. Lett. 80, 3097 (1998)]. Electronic structure calculations predict a surface band gap of 1.1 eV, close to the measured value of 1.14 eV and the previously predicted value (1.2 eV). Despite the successes of this model, high-resolution images reveal an unexpected 3x periodicity (not seen in diffraction) along the [110] row direction, indicating the need for a 4 x 3 model, and putting into question the existence of linear Ga tetramers.

Statin inhibition of Fc receptor-mediated phagocytosis by macrophages is modulated by cell activation and cholesterol

OBJECTIVES

An inflammatory response to altered lipoproteins that accumulate in the arterial wall is a major component of the pathogenesis of atherosclerosis. Statins reduce plasma levels of low-density lipoprotein (LDL) and are effective treatments for atherosclerosis. It is hypothesized that they also modulate inflammation. The aim of this study was to examine whether lovastatin inhibits macrophage inflammatory processes and clarify its mechanism of action.

METHODS AND RESULTS

We examined the effects of statins on phagocytosis of antibody-coated red blood cells by cultured human monocytes and mouse peritoneal macrophages. Lovastatin, simvastatin, and zaragozic acid, a squalene synthase inhibitor, blocked Fc receptor-mediated phagocytosis by cultured human monocytes and mouse peritoneal macrophages. The inhibitory effect of lovastatin on Fc receptor-mediated phagocytosis was prevented completely by addition of mevalonate, farnesyl pyrophosphate, LDL, or cholesterol to the culture medium. The inhibitory effect of zaragozic acid was reversed by addition of LDL, but not by the addition of geranylgeranyl pyrophosphate, to the medium. In addition, the effect of lovastatin on phagocytosis is a function of cell activation because treatment of cells with tumor necrosis factor-alpha or lipopolysaccharide prevented inhibition of phagocytosis by lovastatin.

CONCLUSIONS

The inhibition of Fc receptor-mediated phagocytosis of lovastatin is related to its effect on cholesterol biosynthesis rather than its effect on the formation of isoprenoids.

[Ischemic preconditioning reduces lung ischemia reperfusion injury in vivo rabbits]

Thirty male Japanese white rabbits were randomized into two groups. Fifteen rabbits were treated with ischemic preconditioning(their left lung hilus clamped for 10 min and released for 15 min; Group IP). Fifteen rabbits were not treated with ischemic preconditioning(Group C). Then the left lung hilus of both groups were occlused for 60 min and reperfused for 60 min. The results were that after 60 min of reperfusion, in Group IP, the contents of angiotensin II (Ang II) and artery oxygen tension(PaO2) in blood samples and the contents of superoxide dismutase in lung tissue were significantly higher, while the mean pulmonary artery pressure in blood samples, the wet/dry ratio and malondialdehyde content in lung tissue were significantly lower than those in Group C; Histological findings showed less damage in Group IP. It is suggested that lung ischemic preconditioning can reduce normothermic rabbit lung ischemia-reperfusion injury.

Lysosomal enzymes in the macronucleus of Tetrahymena during its apoptosis-like degradation

A key characteristic of apoptosis is its regulated nuclear degradation. Apoptosis-like nuclear degradation also occurs in the ciliated unicellular organism, Tetrahymena thermophila. Chromatin of the macronucleus undergoes massive condensation, a process that can be blocked by caspase inhibitors. The nucleus becomes TUNEL-positive, and its DNA is cleaved into nucleosome-sized fragments. In a matter of hours the macronucleus is completely degraded, and disappears. The condensed nucleus sequesters acridine orange, which means that it might become an acidic compartment. We therefore asked whether lysosomal bodies fuse with the condensed macronucleus to form an autophagosome. We monitored acid phosphatase (AP) activity, which is associated with lysosomal bodies but is not found in normal nuclei. We find that after the macronucleus condenses AP activity is localized in cap-like structures at its cortex. Later, after the degrading macronucleus loses much of its DNA, acid phosphatase deposits appear deeper within the nucleus. We conclude that although macronuclear elimination is initiated by an apoptosis-like mechanism, its final degradation may be achieved through autophagosomy.

Cardiac ischemic preconditioning improves lung preservation in valve replacement operations

BACKGROUND

Previous work has shown that cardiac ischemic preconditioning reduces cardiac reperfusion injury. We investigated whether cardiac ischemic preconditioning can improve lung preservation in patients who undergo valve replacement.

METHODS

Forty patients with rheumatic heart disease requiring valve replacement were randomly divided into two groups. Twenty patients received two cycles of 3 minutes of aortic cross-clamping and 2 minutes of reperfusion before cardioplegic arrest (group IP), and 20 patients underwent 10 minutes of cardiopulmonary bypass (group C, control group). Blood samples from the pulmonary vein were collected to measure levels of polymorphonuclear leukocytes, superoxide dismutase, malonedialdehyde, and thromboxane B2, and arterial oxygen tension. Blood samples from the coronary sinus were used to measure calcitonin gene-related peptide values. Hemodynamic data were recorded by a pulmonary artery Swan-Ganz catheter. Lung tissue was collected after 1 hour of reperfusion to evaluate morphology. Clinical outcome data were recorded.

RESULTS

In group C (cardiopulmonary bypass and cardioplegic arrest), the levels of polymorphonuclear leukocytes, thromboxane B2, malonedialdehyde, and calcitonin gene-related peptide were increased after 1 hour of reperfusion, whereas the value for superoxide dismutase was decreased. In group IP, preconditioning attenuated the increase in polymorphonuclear leukocytes, thromboxane B2, and malonedialdehyde (p < 0.05) and increased superoxide dismutase and calcitonin gene-related peptide levels (p < 0.05). Preconditioning also increased arterial oxygen tension and cardiac index compared with controls (p < 0.05) and decreased mean pulmonary artery pressure and pulmonary vascular resistance index (p < 0.05). Histologic findings showed less lung injury and a lower polymorphonuclear leukocyte count in group IP than in group C (p < 0.05). Group IP had fewer postoperative pulmonary complications and a shorter intubation time.

CONCLUSIONS

Cardiac ischemic preconditioning improves lung preservation in patients having valve replacement. The mechanism may be that cardiac ischemic preconditioning reduces the accumulation of polymorphonuclear leukocytes in lung tissue and decreases the formation of oxygen free radicals.

Nuclear death in living Tetrahymena: the case of the haploid nuclei

During sexual conjugation in Tetrahymena the micronucleus divides meiotically, producing four haploid nuclei. While one of these nuclei divides mitotically to yield two genetically identical gametic pronuclei, a stationary pronucleus and a migratory pronucleus, the remaining three haploid nuclei degenerate and disappear. Typically, they migrate to the posterior end of the cell where they remain as residual bodies until they disappear. In the present study we asked whether degenerating haploid nuclei share any properties with apoptotic nuclei. Specifically, we wondered whether they would be stained by "apofluor", a combination of vital fluorescent indicators that differentially stains apoptotic nuclei in living cells. "Apofluor" includes acridine orange, which becomes trapped in acidic compartments and stains lysosomal bodies a brilliant orange-red, and Hoechst 33342, which binds to DNA and stains nuclei bright blue. With this dye combination, while ordinary nuclei stain blue, the apoptotic macronucleus stains first blue-green, then yellow, and finally orange. The progression in color is presumed to be due to the accumulation of protons in the apoptotic nucleus compartment. We found that three of the four post-meiotic haploid nuclei, those that are eliminated, were stained differentially green, then yellow, and then come to be indistinguishable from the orange lysosomal bodies. Differential staining can occur even while the nuclei are located at the anterior ends of the cells, and before the "viable" nucleus divides to form pronuclei. These results indicate that haploid nuclei in the process of degradation are differentially stained in living cells by "apofluor", and that the differential staining occurs early in the elimination process. Further, since the degenerating haploid nuclei are stained by "apofluor" it is likely that they are degraded by a mechanism similar to the elimination of the apoptotic macronucleus.

[Hemodynamic and pathologic changes in open abdominal wound after seawater immersion in dog]

OBJECTIVE

To study the experimental basis for the treatment to the sick and wounded with abdominal open wound in land warfare and naval battle.

METHODS

Animal model was made with adult dogs to observe the changes of mean artery pressure (MAP), pulmonary capillary wedge pressure (PCWP), central vein pressure (CVP), cardiac output (CO), cardiac index (CI) and pathologic changes of heart, pulmonary, hepatic, nephritic, intestinal, and gastric tissues under the optical and electrical microscope.

RESULTS

Comparing with simple open abdominal, the hemodynamic disorder in open wound after seawater immersion was more serious; with a higher death rate.

CONCLUSIONS

There was differences in hemodynamic and pathologic changes in seawater immersion wound and general wound. The body damaged is seriously when open abdominal wound immersed in seawater. Special measure must be taken in treating open abdominal wound after seawater immersion.

[Multiple organ dysfunction syndrome after open chest wound and seawater immersion: experimental study]

OBJECTIVE

To evaluate the effect of seawater immersion on multiple organ dysfunction syndrome (MODS) after chest trauma.

METHODS

Twenty health dogs were divided into two groups. Right open pneumothorax was induced in both control group (n = 10) and experimental group (n = 10). After induction of chest trauma, animals in the experimental group were immersed in artificial seawater. Blood samples were taken at seven different intervals for assessing blood gas, plasma level of TNFalpha, and IL-1 beta. Changes of serum alanine aminotransferase (ALT), aspartate amino-transferase (AST), creatine kinase (CK) lactate dehydrogenase (LDH) and creatinine (Cr) were measured. At the end of study, lung was harvested for assessing lung water content and ratio of wet weight and dry weight.

RESULTS

A significant elevation of ALT, AST, CK and LDH was observed in both groups. Organ functional parameters in the experimental group were consistent with the failure standard at 30 minutes after seawater immersion, and those in the control group at 4 hours. Post-trauma mortality and incidence of MODS were much higher in the experimental group than those in the control group (P < 0.01). The plasma levels of TNFalpha and IL-1 beta significantly increased at 30 minutes and reached the highest level at 60 minutes after seawater immersion. The time of peak level appeared earlier in the experimental group than that in the control group.

CONCLUSION

Seawater immersion after open chest trauma results in high incidence of MODS and high mortality rate due to progressive dysfunction of multiple organs.

How commonly are children hospitalized for dehydration eligible for care in alternative settings?

BACKGROUND

Avoiding unnecessary hospitalization has long been a goal of child health care providers. Managed care practice environments increasingly pressure the practicing pediatrician to avoid hospitalization.

OBJECTIVES

To estimate the proportion of childhood dehydration hospitalizations eligible for care in alternative settings (eg, short-stay treatment and triage units, home nursing) and to assess the type and duration of services that might be required for alternative setting care of children with these illness episodes.

DESIGN

All dehydration hospitalizations for the 198 593 children (aged > 1 month and < 19 years) dwelling in Rochester, NY (Monroe County), between 1991 and 1995 were identified in county-wide hospital discharge computer files. Medical records were reviewed for a random sample of 380 of the hospitalizations. Children with major underlying conditions were excluded from analysis because of higher risk for deterioration, and greater complexity of medical care might render alternative settings inappropriate. Measures included a 4-item score estimating level of dehydration, serum bicarbonate level at presentation, and time to rehydration. Rehydration was defined as a drop in urine-specific gravity to 1.010 or less or reduction of fluid administration to the maintenance rate.

RESULTS

Altogether, 1121 dehydration hospitalizations occurred during the study period. Based on medical record review for a random sample of 380 of these 1121, major underlying problems were present in 27.4% (104) of hospitalizations sampled. Simple, acute gastroenteritis accounted for 75.4% (208) of 276 hospitalizations remaining in the sample. Levels of dehydration for these children were estimated as at least 5% for 51.0% (106) and at least 10% for 16.3% (34) of hospital admissions, and serum bicarbonate levels were 12 mmol/L or less for 26.0% (54). Time from hospital admission to rehydration was no greater than 12 hours for 79.3% (165) and no greater than 24 hours for 94.7% (197). However, hospital stay was generally substantially longer. The time hospitalized following rehydration represented 85.8% of the average inpatient stay. Hospital discharge was heavily concentrated in daytime hours, although the children achieved rehydration at all hours of the day. No deterioration occurred during hospitalizations studied.

CONCLUSION

Nearly all children hospitalized for simple, acute gastroenteritis in Rochester might be eligible for care in alternative settings designed to provide hospital-level care for short periods.

Ischemic preconditioning improves preservation with cold blood cardioplegia in valve replacement patients

OBJECTIVE

The purpose of this study was to test the hypothesis that ischemic preconditioning improves myocardial protection in valve replacement patients undergoing cold-blood cardioplegic arrest and to study the mechanisms of human myocardial ischemic preconditioning initially.

METHODS

Forty patients who required double valve replacement were studied. After the institution of cardiopulmonary bypass, 20 patients were preconditioned with two cycles of 3 min of aortic cross-clamping and 2 min of reperfusion before cardioplegic arrest (group IP). Twenty patients were not preconditioned as controls (group C). All hearts were arrested with 4 degrees C cold-blood cardioplegic solution. During perioperation, the blood samples were collected from coronary sinus and radial artery, which were used to measure calcitonin gene-related peptide (CGRP) and creatine kinase-MB (CK-MB). The right atrial myocardial tissue was collected to measure superoxide dismutase/malondialdehyde (T-SOD/MDA) and to observe myocardial ultrastructure. Hemodynamic date were measured.

RESULTS

After reperfusion for 30 min, myocardial MDA was significantly lower in group IP than in group C (2.6+/-0.2 vs. 3.8+/-0.3 nM/mg) and T-SOD was significantly higher in group IP than in group C (13.1+/-12.1 vs. 9.2+/-1.2 IU/mg). Ischemic preconditioning significantly increased the production of myocardial CGRP just after preconditioning (92.0+/-4.1 vs. 52.3+/-4.5 pg/ml) and the begin of reperfusion (95.3+/-3.8 vs. 61.2+/-4.9 pg/ml), and deduced the release of CK-MB at 12 h post-reperfusion (77.5+/-9.2 vs. 136.5+/-8.9 IU/l). Preconditioning also improved cardiac function at 30 min and 12 h after reperfusion (cardiac index 2.8+/-0.3 vs. 2.3+/-0.2 l/min per m2 and 2.9+/-0.1 vs. 2.4+/-0.2 l/min per m2).

CONCLUSIONS

Ischemic preconditioning enhance cardioplegic protection in valve replacement patients. The possible protective mechanism was that ischemic preconditioning decreased the production of oxygen free radicals.

Protective effects of ischemic preconditioning on lung ischemia reperfusion injury: an in-vivo rabbit study

BACKGROUND

The goal of this study was to determine the effect of ischemic preconditioning on the extent of normothermic lung ischemia reperfusion injury in rabbits in vivo.

METHODS

Thirty male Japanese white rabbits were randomized into two groups. Fifteen rabbits were treated with ischemic preconditioning (their left lung hilus clamped for 10 minutes and released for 15 minutes (group IP)). Fifteen rabbits were not treated with ischemic preconditioning (group C). Then the left lung hilus of both groups were occluded for 60 minutes and reperfused for 60 minutes. Mean arterial pressure, mean pulmonary artery pressure, and core temperature were recorded. Femoral artery blood samples and lung tissue samples were collected after ischemic preconditioning and after 60 minutes of reperfusion.

RESULTS

The lung tissue showed little injury after ischemic preconditioning. After 60 minutes of reperfusion, the angiotensin II (A II) and arterial oxygen tension (PaO2) levels in group IP were significantly higher than those in group C, mean pulmonary artery pressure in group IP was significantly lower than that in group C, the wet/dry ratio and malondialdehyde content of lung tissue in group IP was significantly lower than that in group C, the superoxide dismutase contents of lung tissue in group IP was significantly higher than that in group C, and histological findings showed less damage in group IP than in group C.

CONCLUSION

Lung ischemic preconditioning could reduce normothermic rabbit lung ischemia-reperfusion injury. The possible mechanisms are increased production of endogenous A II and reduced formation of oxygen free radicals during lung ischemia for 60 minutes followed by reperfusion for 60 minutes.

Ischemic preconditioning enhances donor lung preservation in canine lung transplantation

OBJECTIVE

To prove the protective effect of lung ischemic preconditioning on enhancing the canine lung preservation and reducing allograft lung dysfunction after transplantation.

METHODS

Ten pairs of adult canines underwent left lung allotransplantation. Five donors were treated with ischemic preconditioning [their left hilus was clamped for 10 minutes and released for 15 minutes (Group IP)], and five donors were not treated with ischemic preconditioning (Group C). The donor lungs were flushed with 4 degrees C Euro-Collin's solution (ECS) and stored in the same solution for two and a half hour, then transplanted to the recipient canines, who were observed for one to two hours after transplantation. The lung venous blood of the recipient and the donor lung tissue were collected just after thoracotomy and one hour after reperfusion of the transplanted lung in both groups.

RESULTS

The number of polymorphonuclear (PMN) was significantly higher in Group IP than in Group C (P < 0.05). However, the number of PMN in lung interstitium under microscope was less in Group IP than in Group C. The thromboxane (TXB2), malondialdehyde (MDA) and mean pulmonary artery pressure (MPAP) contents were significantly lower in Group IP than in Group C (P < 0.05). The superoxide dismutase (SOD) and the lung venous blood oxygen tension (PvO2) contents were significantly higher in Group IP than in Group C (P < 0.05). Histological findings showed less damages in Group IP than in Group C.

CONCLUSIONS

The protective effect of ischemic preconditioning together with ECS flush and storage is superior to using ECS alone. The possible mechanisms may be that ischemic preconditioning inhibits the accumulation and activation of PMN in lung tissue and reduces the production of oxygen free radicals.

[Myocardioprotective effects of preconditioning in patients undergoing open heart operation]

OBJECTIVE

To investigate the myocardial protective effects of ischemic preconditioning (IP) on adult patients who undergoing prolonged open heart operation for complex heart diseases.

METHODS

30 patients were evenly divided into two groups at random. IP was elicited twice for 2 minutes ischemia from occlusion of vena cava and aorta followed by 3 minutes of reperfusion under cardiopulmonary bypass. Dynamic changes of ATP and purine metabolites in myocardium were measured. Electrocardiogram, leakage of myocardial enzymes, activities of SOD and LPO in serum and myocardial mechanics were investigated.

RESULTS

IP reduced ATP repletion and maintained a higher ATP content in ischemic myocardium (P < 0.05 vs control group at 30, 60, and 90 minutes of ischemia). Reduced inosine content was found in IP group (P > 0.05). The inosine/adenosine ratio at 30, 60 and 90 minutes of ischemia was 4.2 vs 14.1, 17.6 vs 28.2, 29.2 vs 71.3 for the IP and control groups, respectively, P < 0.05). There were also significant differences between the two groups in changes of ST-segment shifting, myocardial contractile and early postoperative recovery.

CONCLUSIONS

IP can reduce ischemia-reperfusion injury on prolonged ischemic myocardium in humans even when combined with cold cardioplegia. Decreased inosine production and inosine/adenosine ratio in ischemic myocardium may be an important mechanism of IP, by which the production of oxygen free radicals are decreased during early reperfusion.

Protective effects of ischemic preconditioning on donor lung in canine lung transplantation

BACKGROUND

Myocardial ischemic preconditioning has been found to protect the myocardium. We hypothesized that lung ischemic preconditioning might enhance canine lung preservation and reduce allograft lung dysfunction after transplantation.

METHODS

Ten pairs of adult canines underwent left lung allotransplantation. Five donors were treated with ischemic preconditioning (their left hilus clamped for 10 min and released for 15 min [group IP]), and five donors were not treated with ischemic preconditioning (group C). The donor lungs were flushed with 4 degrees C Euro-Collins solution (ECS) and stored in the same solution for 2 1/2 h, then transplanted to the recipient canines. The animals were observed for 1 to 2 h after transplantation. The lung venous blood of the recipient and donor lung tissue was collected just after thoracotomy and 1 h after reperfusion of the transplanted lung in both groups.

RESULTS

The numbers of polymorphonuclear leukocytes (PMNs) in the pulmonary venous blood after reperfusion were significantly higher in group IP than in group C (p<0.05). However, the numbers of PMNs in lung interstitium under microscopy were less in group IP than in group C. The thromboxane B2, malondialdehyde, and mean pulmonary artery pressure contents were significantly lower in group IP than in group C (p<0.05), and the superoxide dismutase and mixed venous oxygen tension values were significantly higher in group IP than in group C (p<0.05). Histologic findings show less damage in group IP than in group C.

CONCLUSIONS

The protective effects of ischemic preconditioning in conjunction with ECS flush and storage were superior to using ECS alone. The possible mechanisms were that ischemic preconditioning inhibited the accumulation and activation of PMNs in lung tissue and reduced the production of oxygen-free radicals.

ATP releases HSP-72 from protein aggregates after renal ischemia

The pattern of 72-kDa heat-shock protein (HSP-72) induction after renal ischemia suggests a role in restoring cell structure. HSP-72 activity in the repair and release from denatured and aggregated proteins requires ATP. Protein aggregates were purified from normal and ischemic rat renal cortex. The addition of ATP to cortical homogenates reduced HSP-72, Na(+)-K(+)-ATPase, and actin in aggregates subsequently isolated, suggesting that their interaction is ATP dependent. Altering ATP hydrolysis in the purified aggregates, however, had different effects. ATP released HSP-72 during reflow and preserved Na(+)-K(+)-ATPase association with aggregates at 2 h but had no effect in controls or at 6 h reflow and caused no change in actin. These results indicate that HSP-72 complexes with aggregated cellular proteins in an ATP-dependent manner and suggests that enhancing HSP-72 function after ischemic renal injury assists refolding and stabilization of Na(+)-K(+)-ATPase or aggregated elements of the cytoskeleton, allowing reassembly into a more organized state.

Pertussis in Arkansas

Although the morbidity and mortality due to pertussis has declined, 109 infants and children were diagnosed and reported to the Arkansas Department of Health with pertussis in 1990-1994. Case rates in Arkansas over this five year period were lower than national case rates (0.9/100,000 vs. 1.77/100,000; p < 0.0001) while the case fatality rates were similar. Hospitalization, admissions to the intensive care, and deaths in Arkansas were more commonly demonstrated in children < 1 year of age. Although recent data concerning the safety and efficacy of the acellular vaccines is promising, at this time the primary series should still be given with the whole-cell vaccine until more data becomes available.

Characterization of a 17-kilodalton antigen of Bartonella henselae reactive with sera from patients with cat scratch disease

A library of Bartonella (Rochalimaea) henselae DNA was constructed in the cloning vector lambda ZAPII and screened for expression of antigenic proteins by using a pool of sera from patients who had been diagnosed with cat scratch disease (CSD) and had antibodies to Bartonella spp., as determined by indirect fluorescent-antibody (IFA) assay. Ten immunoreactive phages were subcloned as recombinant plasmids by in vivo excision. All 10 recombinants expressed a protein of approximately 17 kDa when they were examined by immunoblot with the pool of human sera. Restriction endonuclease digestion of each recombinant plasmid indicated seven profiles, suggesting that cloning bias was not the reason for repeated isolation of clones expressing the 17-kDa antigen. The gene coding for the 17-kDa antigen was sequenced and shown to code for an open reading frame of 148 amino acids with a predicted molecular mass of 16,893 Da. The amino terminus of the deduced amino acid sequence was hydrophobic in nature and similar in size and composition to signal peptides found in gram-negative bacteria. The remainder of the deduced amino acid sequence was more hydrophilic and may represent surface-exposed epitopes. Further subcloning of the 17-kDa antigen as a biotinylated fusion protein in the expression vector PinPoint Xa-2 resulted in a 30-kDa protein that was highly reactive on immunoblots with individual serum samples from patients with CSD. The agreement between reactivity with the 30-kDa fusion protein on immunoblot analysis and the results obtained by IFA assay was 92% for IFA-positive sera and 88% for IFA-negative sera. The recombinant-expressed 17-kDa protein should be of value as an antigen for serologic diagnosis of CSD and Bartonella infections and warrants further study in attempts to develop a subunit vaccine to prevent long-term Bartonella infection in cats and the potential for further spread of these organisms to humans.

Characterization of human coronary artery atherosclerotic plaque fluorescence emission

Preliminary trials using fluorescence guidance of laser ablation in femoral arteries have been successful. There have, however, been few studies of the characteristics of fluorescence emissions from coronary arteries. A large series of fluorescence emission spectra from human coronary artery specimens was examined. Analysis included: fluorescence emission during excitation with ultraviolet and visible light; histologic correlations between plaque content and thickness, averaged spectra and fluorescence intensity ratios; and differences in specific plaque morphology with excitation of the same coronary specimens at 325 or 458 nm. Ratios of fluorescence emission intensity at selected wavelengths were calculated for both 325 and 458 nm excitation (13 wavelengths, 78 ratios for 325 nm; 11 wavelengths, 55 ratios for 458 nm). The following were found: atherosclerotic lesions in human coronary arteries were characterized by an increase in normalized fluorescence intensity at longer wavelengths when excited with either ultraviolet or visible light; calcific plaque content greater than 10% in lesions more than 1 mm thick was identified by increased normalized fluorescence intensity at 443 nm during excitation at 325 nm; and fatty plaque content correlated with fluorescence intensity ratios during 325 nm excitation, whereas fibrous and calcific content correlated well with fluorescence ratios during 458 nm excitation. It is concluded that characteristic fluorescence emission has the potential to correctly identify and characterize plaque morphology in human coronary arteries.

In vitro inhibition of Na-K-ATPase by trace metals: relation to renal and cardiovascular damage

The potential role of trace metals in the pathogenesis of various disease states, especially of renal and cardiovascular disease, has been recognized increasingly. Moreover, altered membrane transport was recently incriminated to play a role in renal tubular syndromes, such as the Fanconi syndrome, as well as in the pathogenesis of volume dependent hypertension. We therefore investigated the possible in vitro effects of various trace metals on Na-K-ATPase, the biochemical correlate of active cellular transmembrane sodium and sodium-dependent transport. To more closely mimic the in vivo situation, we deliberately chose as enzyme source renal tissue homogenate, which may contain protective agents. Under these experimental conditions, the metals studied inhibited the enzyme quantitatively in the following order: Hg greater than Pb greater than Cd greater than Ur greater than Cu greater than Zn greater than Mn greater than Ba greater than Ni greater than Sr. Enzyme kinetic studies showed that Hg, Pb, and Cd competitively, and Cu noncompetitively, inhibited the enzyme. In general, Mg-ATPase was significantly less sensitive to the trace metals. Accumulation of these metals may present serious health hazards by producing a general defect in cell membrane transport. From the other metals studied, i.e., Mn, Ba, Ni and Sr, some may have toxic effects via other mechanisms, whereas some may exert a protective role against toxicity of other agents including metal ions.

Circulating inhibitor of sodium-potassium-activated adenosine triphosphatase after expansion of extracellular fluid volume in rats

1. Serum was collected from normal rats and from rats volume-expanded with isotonic sodium chloride solution. 2. The serum was fractionated by gel filtration on Sephadex G-25 and each fraction was tested for inhibitory activity against sodium-potassium-activated adenosine triphosphatase prepared from rat kidney homogenate. 3. A single low-molecular-weight fraction, eluting after the salts and after exogenously added lysine-vasopressin, had significantly greater enzyme inhibitory activity when obtained from serum of volume-expanded animals than from control serum. 4. As this fraction has been shown in previous independent studies to contain a natriuretic factor, it may be concluded that one property of this factor is the ability to inhibit sodium-potassium-activated adenosine triphosphatase.

Further characterization of the natriuretic factor derived from kidney tissue of volume-expanded rats. Effects on short-circuit current and sodium-potassium-adenosine triphosphatase activity

Boiled homogenates of kidneys from volume-expanded and hydropenic rats were subjected to column chromatography. The fraction eluting within the range of partition coefficients (Kav) 0.76-0.89 (fraction III) was lyophilized and the effects of this semipurified preparation were assessed on short-circuit current (SCC) across isolated frog skin, on rat kidney cortex Na-K-ATPase activity, and on sodium excretion by the rat in vivo. At a dose of 500 mug/ml, fraction III from expanded rat kidney inhibited SCC by 21 +/- 5% (P less than 0.01), whereas the same fraction from hydropenic rat kidney produced an insignificant change in SCC of 2 +/- 8 %. In a dose-response study, 50, 150, 500, and 1,500 mug/ml of fraction III from expanded rat kidney inhibited SCC by 4, 8, 19, and 28%, respectively; 500, 1,000 and 1,500 mug/ml inhibited Na-K-ATPase activity by 11, 22, and 49%, respectively. An identical study with fraction III from hydropenic animals showed no significant effect in either assay. Also, fractions from expanded and hydropenic rats, eluted after fraction III (fractions IV and V), had no effect on SCC or Na-K-ATPase activity. Fraction III also produced significant natriuresis in vivo at a dose of 500 mug/ml, confirming our observations that a natriuretic principle may be recovered from the kidneys of volume-expanded rats. We suggest that this natriuretic principle may act by reducing active sodium transport via inhibition of Na-K-ATPase.