Mediation of tubuloglomerular feedback by adenosine: evidence from mice lacking adenosine 1 receptors

Adenosine is a determinant of metabolic control of organ function increasing oxygen supply through the A2 class of adenosine receptors and reducing oxygen demand through A1 adenosine receptors (A1AR). In the kidney, activation of A1AR in afferent glomerular arterioles has been suggested to contribute to tubuloglomerular feedback (TGF), the vasoconstriction elicited by elevations in [NaCl] in the macula densa region of the nephron. To further elucidate the role of A1AR in TGF, we have generated mice in which the entire A1AR coding sequence was deleted by homologous recombination. Homozygous A1AR mutants that do not express A1AR mRNA transcripts and do not respond to A1AR agonists are viable and without gross anatomical abnormalities. Plasma and urinary electrolytes were not different between genotypes. Likewise, arterial blood pressure, heart rates, and glomerular filtration rates were indistinguishable between A1AR(+/+), A1AR(+/-), and A1AR(-/-) mice. TGF responses to an increase in loop of Henle flow rate from 0 to 30 nl/min, whether determined as change of stop flow pressure or early proximal flow rate, were completely abolished in A1AR(-/-) mice (stop flow pressure response, -6.8 +/- 0.55 mmHg and -0.4 +/- 0.2 in A1AR(+/+) and A1AR(-/-) mice; early proximal flow rate response, -3.4 +/- 0.4 nl/min and +0.02 +/- 0.3 nl/min in A1AR(+/+) and A1AR(-/-) mice). Absence of TGF responses in A1AR-deficient mice suggests that adenosine is a required constituent of the juxtaglomerular signaling pathway. A1AR null mutant mice are a promising tool to study the functional role of A1AR in different target tissues.

Role of endothelial [Ca2+]i in activation of eNOS in pressurized arterioles by agonists and wall shear stress

In cultured endothelial cells, Ca2+-dependent and -independent activation of nitric oxide (NO) synthesis to agonists and flow/wall shear stress (WSS) has been demonstrated. However, the presence and function of these pathways are less well known in microvessels that can be exposed to a high level of WSS. We hypothesized that the role of changes in endothelial intracellular calcium concentration ([Ca2+]i) is different in agonist- and WSS-induced release of NO. Thus changes in endothelial [Ca2+]i and diameter of intact pressurized (approximately 100 microm at 80 mmHg) gracilis skeletal muscle arterioles of rats were measured by fluorescent videomicroscopy. Acetylcholine (ACh) and increases in WSS (by increasing intraluminal flow) elicited dilations (maximum 91 +/- 2% and 34 +/- 4%) that could be inhibited by N(omega)-nitro-L-arginine methyl ester (L-NAME), a NO synthase blocker. In diameter-clamped arterioles, ACh caused substantial increases in the endothelial calcium fluorescence ratio (ER(Ca), maximum 43 +/- 5%), which was significantly greater than changes in ER(Ca) (maximum approximately 10%) to increases in WSS. The Ca(2+) ionophore A-23187 also substantially increased ER(Ca) (maximum 38 +/- 5%) and elicited significant L-NAME-sensitive arteriolar dilations (maximum 45 +/- 7%). Intraluminal administration of the tyrosine kinase inhibitor genistein had no effect on dilations induced by ACh or the NO donor sodium nitroprusside, whereas it eliminated WSS-induced dilations. Collectively, our data suggest that, in endothelium of skeletal muscle arterioles, NO synthesis is activated by shear stress without a substantial increase in [Ca2+]i, most likely by activation of tyrosine kinase pathways, whereas NO release by ACh and A-23187 is associated with substantial increases in [Ca2+]i.

Interleukin-10 inhibits polymethylmethacrylate particle induced interleukin-6 and tumor necrosis factor-alpha release by human monocyte/macrophages in vitro

Periprosthetic membranes commonly observed at sites of total joint implant loosening exhibit abundant macrophages and particulate debris. Macrophages phagocytose orthopedic debris and release the pro-inflammatory mediators interleukin-1, interleukin-6, tumor necrosis factor-alpha, and prostaglandin E2. Populations of activated lymphocytes are often seen in periprosthetic membranes. These lymphocytes may modulate the monocyte/macrophage response to particulate debris and influence aseptic loosening. In addition, other immunologic agents, such as interleukin-10, are present in tissues harvested from the bone-implant interface of failed total joint arthroplasties. The present study examined the effects of interleukin-10 on polymethylmethacrylate (PMMA) particle challenged human monocyte/macrophages in vitro. Human monocyte/macrophages isolated from buffy coats of five healthy individuals were exposed to 1-10 microm PMMA particles. Interleukin-10 was added to the monocyte/macrophages with and without the addition of PMMA particles. Interleukin-10-induced alterations in monocyte/macrophage metabolism were determined measuring interleukin-6 and tumor necrosis factor-alpha release by the cells following exposure to PMMA particles. Exposure of the monocyte/macrophages to PMMA particles resulted in a dose-dependent release of interleukin-6 and tumor necrosis factor-alpha at 48 h. Interleukin-10 reduced the levels of interleukin-6 and tumor necrosis factor-alpha release by macrophages in response to PMMA particles in a dose-dependent manner. At 48 h, particle-induced interleukin-6 release was inhibited by 60 and 90% with 1.0 and 10.0 ng/ml treatments of interleukin-10, respectively. At 48 h, particle-induced tumor necrosis factor-alpha release was inhibited by 58 and 88% with 1.0 and 10.0 ng/ml treatments of interleukin-10, respectively. Interleukin-10 challenge alone did not significantly alter basal interleukin-6 or tumor necrosis factor-alpha release relative to control cultures. The data presented in this study demonstrate that the anti-inflammatory cytokine, interleukin-10, inhibits monocyte/macrophage release of the pro-inflammatory cytokines interleukin-6 and tumor necrosis factor-alpha in response to PMMA particle challenge in vitro.

[Intravesical instillation of cytotoxic T-lymphocytes induced by soluble tumor antigen in the prophylaxis of recurrence of bladder cancer]

OBJECTIVE

To explore a new method for preventing the recurrence of bladder cancer.

METHODS

With the adjuvant of BCG, cytotoxic T-lymphocytes (CTLs) were induced from human peripheral blood mononuclear cells (PBMC) by bladder tumor soluble antigen which was extracted through salt-infiltrating biochemical procedures from autologous bladder tumor. Intravesical instillation of CTLs together with their supernatants after culture for 8 to 10 days was performed in 37 patients with superficial bladder cancer after surgery. The effects of the treatment were evaluated by endocytoscopy, pathological examinations and ELISA assays for the levels of cytokines IL-2, TNF-alpha and IFN-gamma in the patients' serum and urine. The distribution of T-lymphocyte subpopulations was also monitored by SAP immuno-histochemical techniques.

RESULTS

The proportion of CD3+ and CD4+ T-lymphocyte subpopulations increased significantly while CD8+ T-lymphocyte subpopulation was stable. The ratio of CD4+ to CD8+ increased to 1.60 +/- 0.29. The levels of cytokines IL-2, TNF-alpha and IFN-gamma in serum and urine increased significantly, especially the level of TNF-alpha in urine. Pathological studies revealed that non-specific inflammation is the major change in the bladder mucosa after therapy. Follow-up for 6-26 months showed that 1 patient havd moderate heterogeneity in bladder mucosa. The recurrence rate was 2.7%. Side effects were not found except transient lower fever or hematuria.

CONCLUSION

Intravesical insitillation of CTLs could effectively prevent the recurrence of superficial bladder cancer after the improvement of immunological reactivity in the whole body.

Ki-67, cyclin E, and p16INK4 are complimentary surrogate biomarkers for human papilloma virus-related cervical neoplasia

Prior studies of Ki-67, cyclin E, and p16 expression have suggested that these biomarkers may be preferentially expressed in cervical neoplasia. This study examined and compared the distribution of staining for these three antigens in 1) normal and reactive epithelial changes, 2) diagnostically challenging cases (atypical metaplasia and atypical atrophy), 3) squamous intraepithelial lesions (SIL), and 4) high-and low-risk human papilloma virus (HPV) type-specific SIL. One hundred four epithelial foci from 99 biopsies were studied, including low-grade squamous intraepithelial lesions (LSIL; 24), high-grade squamous intraepithelial lesions (HSIL; 36), mature or immature (metaplastic) squamous epithelium (29), and atrophic or metaplastic epithelium with atypia (15). Cases were scored positive for Ki-67 expression if expression extended above the basal one third of the epithelium, for cyclin E if moderate to strong staining was present, and for p16 if moderate to strong diffuse or focal staining was present. HPV status was scored by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis of extracted DNA. Immunohistochemical findings were correlated with histologic and viral data. Overall, a histologic diagnosis of SIL correlated strongly with all of the biomarkers used (p <0.001). Positive scores for Ki-67, cyclin E, and p16 were seen in 68.4%, 96.7%, and 100% of LSILs and 94.7%, 91.6%, and 100% of HSILs, respectively. Positive predictive values of these three biomarkers for HPV were 82.4%, 89.5%, and 91.4%, respectively. The positive predictive value for HPV of either cyclin E or p16 was 88.7%. Strong diffuse staining for p16 was significantly associated with high-risk HPV-associated lesions. Normal or reactive epithelial changes scored positive for the three biomarkers in 7.7%, 8.0%, and 12%, respectively. Limitations in specificity included minimal or no suprabasal staining for Ki-67 in immature condylomas and occasional suprabasal staining of reactive epithelial changes (10%), diffuse weak nuclear cyclin E staining in some normal or metaplastic epithelia, and diffuse weak basal p16 staining and occasional stronger focal positivity in normal epithelia. Ki-67, cyclin E, and p16 are complementary surrogate biomarkers for HPV-related preinvasive squamous cervical disease. (Because cyclin E and p16 are most sensitive for LSIL and HSIL [including high-risk HPV], respectively, use of these biomarkers in combination for resolving diagnostic problems, with an appreciation of potential background staining, is recommended.)

Myelin antigen-specific CD8+ T cells are encephalitogenic and produce severe disease in C57BL/6 mice

Encephalitogenic T cells that mediate experimental autoimmune encephalomyelitis (EAE) are commonly assumed to be exclusively CD4+, but formal proof is still lacking. In this study, we report that synthetic peptides 35-55 from myelin oligodendrocyte glycoprotein (pMOG(35-55)) consistently activate a high proportion of CD8+ alphabetaTCR+ T cells that are encephalitogenic in C57BL/6 (B6) mice. The encephalitogenic potential of CD8+ MOG-specific T cells was established by adoptive transfer of CD8-enriched MOG-specific T cells. These cells induced a much more severe and permanent disease than disease actively induced by immunization with pMOG(35-55). CNS lesions in pMOG(35-55) CD8+ T cell-induced EAE were progressive and more destructive. The CD8+ T cells were strongly pathogenic in syngeneic B6 and RAG-1(-/-) mice, but not in isogeneic beta2-microglobulin-deficient mice. MOG-specific CD8+ T cells could be repeatedly reisolated for up to 287 days from recipient B6 or RAG-1(-/-) mice in which disease was induced adoptively with <1 x 10(6) T cells sensitized to pMOG(35-55). It is postulated that MOG induces a relapsing and/or progressive pattern of EAE by eliciting a T cell response dominated by CD8+ autoreactive T cells. Such cells appear to have an enhanced tissue-damaging effect and persist in the animal for long periods.

EDHF mediates flow-induced dilation in skeletal muscle arterioles of female eNOS-KO mice

Vasodilation to increases in flow was studied in isolated gracilis muscle arterioles of female endothelial nitric oxide synthase (eNOS)-knockout (KO) and female wild-type (WT) mice. Dilation to flow (0-10 microl/min) was similar in the two groups, yet calculated wall shear stress was significantly greater in arterioles of eNOS-KO than in arterioles of WT mice. Indomethacin, which inhibited flow-induced dilation in vessels of WT mice by approximately 40%, did not affect the responses of eNOS-KO mice, whereas miconazole and 6-(2-proparglyoxyphenyl)hexanoic acid (PPOH) abolished the responses. Basal release of epoxyeicosatrienonic acids from arterioles was inhibited by PPOH. Iberiotoxin eliminated flow-induced dilation in arterioles of eNOS-KO mice but had no effect on arterioles of WT mice. In WT mice, neither N(omega)-nitro-L-arginine methyl ester nor miconazole alone affected flow-induced dilation. Combination of both inhibitors inhibited the responses by approximately 50%. 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ) alone inhibited flow-induced dilation by approximately 49%. ODQ + indomethacin eliminated the responses. Thus, in arterioles of female WT mice, nitric oxide and prostaglandins mediate flow-induced dilation. When eNOS is inhibited, endothelium-derived hyperpolarizing factor substitutes for nitric oxide. In female eNOS-KO mice, metabolites of cytochrome P-450, via activation of large-conductance Ca2+-activated K+ channels of smooth muscle, mediate entirely the arteriolar dilation to flow.

[Effects of the alterations of membrane shear elastic modulus and viscosity on the deformation and orientation of RBCs]

Neuraminidase can partly remove the surface charge of RBCs through a biochemical interaction; thus it can give rise to alterations in the microstructure of membrane, the shear elastic modulus (E) and the viscosity(micron) of membrane. Changing the time of treatment and the dose of neuraminidase and using a new ektacytometry that can separate deformation index DI into orientation index (DI)or and small deformation index (DI)d for RBCs in shear flow field of low viscosity, we measured (DI)d and the half time t0.5 when the DI recovered to half of the maximum in the process of relaxation for every treated sample. (DI)d and t0.5 were put respectively into the RBC membrane shear elastic modulus formula and the membrane viscosity formula which were put forward by Wen Zong-yao and Yan Zong-yi et al[1]. The rules of the alterations of E and micron were obtained. We also measured DI and (DI)or. It was found that E and micron increased greatly but DI and (DI)or decreased when the dose of neuraminidase and the time of treatment were increased. There was a contrary correlation between them. These data demonstrated that the increase of E and micron weakened the deformability and the ability of orientation of RBCs.

Gender-specific compensation for the lack of NO in the mediation of flow-induced arteriolar dilation

Flow-induced dilation of gracilis muscle arterioles was examined in both genders of control rats and rats chronically treated with N ω-nitro-l-arginine methyl ester (l-NAME). After l-NAME treatment (4 wk), systolic blood pressure was significantly increased compared with control, whereas the plasma concentration of nitrate/nitrite was significantly reduced. Isolated and pressurized arterioles dilated significantly in response to increases in flow (0–25 μl/min). Flow-induced dilation was comparable in arterioles of control andl-NAME-treated rats but was significantly greater in female than in male rats. l-NAME + indomethacin, which abolished flow-induced dilation in arterioles of male control rats, inhibited the dilation by only ∼75% in female control rats. The residual portion of the response was eliminated by additional administration of miconazole, an inhibitor of cytochrome P-450. Indomethacin did not affect the dilation in femalel-NAME-treated rats but completely inhibited the response in male l-NAME-treated rats. The indomethacin-insensitive, flow-induced dilation in female l-NAME-treated arterioles was abolished by miconazole, 6-(2-proparglyoxyphenyl)hexanoic acid, or charybdotoxin. Thus an augmented release of endothelial prostaglandins accounts for the preserved flow-induced dilation in arterioles of male rats, whereas a metabolite of cytochrome P-450 is responsible for the maintenance of flow-induced dilation in female rats, suggesting important differences in the adaptation of the endothelium of arterioles from male and female rats to the lack of nitric oxide (NO) synthesis.

Na+-K+-Cl- cotransporter in rat focal cerebral ischemia

In cultured neurons, the authors previously demonstrated that the Na+-K+-Cl- cotransporter is significantly stimulated by elevated extracellular potassium and glutamate, which are important factors in cerebral ischemic damage. These findings led the authors to hypothesize that stimulation of the cotransporter after ischemia might result in Na+, K+, and Cl- influx, and might contribute to neuron damage. In the current study, the authors investigated such a role of the Na+-K+-Cl- cotransporter in focal cerebral ischemia. Cerebral ischemia was induced by 2-hour occlusion of the left middle cerebral artery (MCA) and 24-hour reperfusion in male spontaneously hypertensive rats (SHRs). Immunocytochemical staining and immunoblotting revealed an up-regulation of expression of the cotransporter protein in neurons in cortex at 24 hours of reperfusion. Artificial cerebral spinal fluid (aCSF) or 100 micromol/L bumetanide (a cotransporter inhibitor) in aCSF were continuously microdialyzed through a microdialysis probe into left cortices throughout 2-hour MCA occlusion and 24-hour reperfusion. Compared with the aCSF-treated group, infarction volume was significantly reduced in the bumetanide-treated group (25%, P < 0.05). In addition, brain water content in the bumetanide-treated brains was decreased by 70% (P < 0.05). These results strongly suggest that the Na+-K+-Cl- cotransporter may play an important role in cerebral ischemic neuronal damage.

Fluorescence, reflectance, and light-scattering spectroscopy for evaluating dysplasia in patients with Barrett's esophagus

BACKGROUND & AIMS

The aim of this study was to assess the potential of 3 spectroscopic techniques (fluorescence, reflectance, and light-scattering spectroscopy) individually and in combination, for evaluating low- and high-grade dysplasia in patients with Barrett's esophagus (BE).

METHODS

Fluorescence spectra at 11 excitation wavelengths and a reflectance spectrum were acquired in approximately 1 second from each site before biopsy using an optical fiber probe. The measured fluorescence spectra were combined with the reflectance spectra to extract the intrinsic tissue fluorescence. The reflectance spectra provided morphologic information about the bulk tissue, whereas light-scattering spectroscopy was used to determine cell nuclear crowding and enlargement in Barrett's epithelium.

RESULTS

Significant differences were observed between dysplastic and nondysplastic BE in terms of intrinsic fluorescence, bulk scattering properties, and levels of epithelial cell nuclear crowding and enlargement. The combination of all 3 techniques resulted in superior sensitivity and specificity for separating high-grade from non-high-grade and dysplastic from nondysplastic epithelium.

CONCLUSIONS

Intrinsic fluorescence, reflectance, and light-scattering spectroscopies provide complementary information about biochemical and morphologic changes that occur during the development of dysplasia. The combination of these techniques (Tri-Modal Spectroscopy) can serve as an excellent tool for the evaluation of dysplasia in BE.

Stimulation of Na-K-2Cl cotransporter in neurons by activation of Non-NMDA ionotropic receptor and group-I mGluRs

In a previous study, we found that Na(+)-K(+)-2Cl(-) cotransporter in immature cortical neurons was stimulated by activation of the ionotropic N-methyl-D-aspartate (NMDA) glutamate receptor in a Ca(2+)-dependent manner. In this report, we investigated whether the Na(+)-K(+)-2Cl(-) cotransporter in immature cortical neurons is stimulated by non-NMDA glutamate receptor-mediated signaling pathways. Expression of the Na(+)-K(+)-2Cl(-) cotransporter and metabotropic glutamate receptors (mGluR1 and 5) was detected in cortical neurons via immunoblotting and immunofluorescence staining. Significant stimulation of cotransporter activity was observed in the presence of both trans-(+/-)-1-aminocyclopentane-trans-1,3-dicarboxylic acid (trans-ACPD) (10 microM), a metabotropic glutamate receptor (mGluR) agonist, and (RS)-3,5-dihydroxyphenylglycine (DHPG) (20 microM), a selective group-I mGluR agonist. Both trans-ACPD and DHPG-mediated effects on the cotransporter were eradicated by bis-(o-aminophenoxy)-N,N,N',N'-tetraacetic acid-AM, a Ca(2+) chelator. In addition, DHPG-induced stimulation of the cotransporter activity was inhibited in the presence of mGluRs antagonist (RS)-1-aminoindan-1,5-dicarboxylic acid (AIDA) (1 mM) and also with selective mGluR1 antagonist 7-(hydroxyimino)cyclopropa[b]chromen-1a-carboxylate ethyl ester (CPCCOEt) (100 microM). A DHPG-induced rise in intracellular Ca(2+) in cortical neurons was detected with Fura-2. Moreover, DHPG-mediated stimulation of the cotransporter was abolished by inhibition of Ca(2+)/CaM kinase II. Interestingly, the cotransporter activity was increased by activation of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor. These results suggest that the Na(+)-K(+)-2Cl(-) cotransporter in immature cortical neurons is stimulated by group-I mGluR- and AMPA-mediated signal transduction pathways. The effects are dependent on a rise of intracellular Ca(2+).

Novel inhibitors of poly(ADP-ribose) polymerase/PARP1 and PARP2 identified using a cell-based screen in yeast

Multicellular organisms must have means of preserving their genomic integrity or face catastrophic consequences such as uncontrolled cell proliferation or massive cell death. One response is a modification of nuclear proteins by the addition and removal of polymers of ADP-ribose that modulate the properties of DNA-binding proteins involved in DNA repair and metabolism. These ADP-ribose units are added by poly(ADP-ribose) polymerase (PARP) and removed by poly(ADP-ribose) glycohydrolase. Although budding yeast Saccharomyces cerevisiae does not possess proteins with significant sequence similarity to the human PARP family of proteins, we identified novel small molecule inhibitors against two family members, PARP1 and PARP2, using a cell-based assay in yeast. The assay was based on the reversal of growth inhibition caused by the heterologous expression of either PARP1 or PARP2. Validation of the assay was achieved by showing that the growth inhibition was relieved by a mutation in a single residue in the catalytic site of PARP1 or PARP2 or exposure of yeast to a known PARP1 inhibitor, 6(5H)-phenanthridinone. In separate experiments, when a putative protein regulator of PARP activity, human poly(ADP-ribose) glycohydrolase, was coexpressed with PARP1 or PARP2, yeast growth was restored. Finally, the inhibitors identified by screening the yeast assay are active in a mammalian PARP biochemical assay and inhibit PARP1 and PARP2 activity in yeast cell extracts. Thus, our data reflect the strength of using yeast to identify small molecule inhibitors of therapeutically relevant gene families, including those that are not found in yeast, such as PARP. The resultant inhibitors have two critical uses (a) as leads for drug development and (b) as tools to dissect cellular function.

Influence of neuraminidase on the characteristics of microrheology of red blood cells

Surface charge was removed from RBC (erythrocyte) membrane to different degrees with biochemical methods, i.e., treatment of RBCs with neuraminidase, either using different doses for the same incubation time (1 hour) or using the same dose (75 milli-unit) for different incubation time. Several rheological properties of the RBCs with surface charge removal were observed, including the deformation index DI (using traditional ektacytometry) orientation index (DI)or and small deformation index (Dl)d (using new ektacytometry), the viscosity at low and high shear rates (using a cone-plate rotating viscosimeter). In addition, photographs of RBCs aggregation under a microscope and the histograms of RBC aggregate size after treatment with neuraminidase were obtained. It is found from these experiments that the decrease of the surface charge of RBCs leads to the decrease in the deformation and orientation indices as well as the increase in blood viscosity.

Cloning and functional characterization of an NAD(+)-dependent DNA ligase from Staphylococcus aureus

A Staphylococcus aureus mutant conditionally defective in DNA ligase was identified by isolation of complementing plasmid clones that encode the S. aureus ligA gene. Orthologues of the putative S. aureus NAD(+)-dependent DNA ligase could be identified in the genomes of Bacillus stearothermophilus and other gram-positive bacteria and confirmed the presence of four conserved amino acid motifs, including motif I, KXDG with lysine 112, which is believed to be the proposed site of adenylation. DNA sequence comparison of the ligA genes from wild type and temperature-sensitive S. aureus strain NT64 identified a single base alteration that is predicted to result in the amino acid substitution E46G. The S. aureus ligA gene was cloned and overexpressed in Escherichia coli, and the enzyme was purified to near homogeneity. NAD(+)-dependent DNA ligase activity was demonstrated with the purified enzyme by measuring ligation of (32)P-labeled 30-mer and 29-mer oligonucleotides annealed to a complementary strand of DNA. Limited proteolysis of purified S. aureus DNA ligase by thermolysin produced products with apparent molecular masses of 40, 22, and 21 kDa. The fragments were purified and characterized by N-terminal sequencing and mass analysis. The N-terminal fragment (40 kDa) was found to be fully adenylated. A fragment from residues 1 to 315 was expressed as a His-tagged fusion in E. coli and purified for functional analysis. Following deadenylation with nicotinamide mononucleotide, the purified fragment could self-adenylate but lacked detectable DNA binding activity. The 21- and 22-kDa C-terminal fragments, which lacked the last 76 amino acids of the DNA ligase, had no adenylation activity or DNA binding activity. The intact 30-kDa C terminus of the S. aureus LigA protein expressed in E. coli did demonstrate DNA binding activity. These observations suggest that, as in the case with the NAD(+)-dependent DNA ligase from B. stearothermophilus, two independent functional domains exist in S. aureus DNA ligase, consisting of separate adenylation and DNA binding activities. They also demonstrate a role for the extreme C terminus of the ligase in DNA binding. As there is much evidence to suggest that DNA ligase is essential for bacterial survival, its discovery in the important human pathogen S. aureus indicates its potential as a broad-spectrum antibacterial target for the identification of novel antibiotics.

Histologic and immunophenotypic classification of cervical carcinomas by expression of the p53 homologue p63: a study of 250 cases

Recent studies of the p53 homologue p63 indicate that this gene is preferentially expressed in basal and immature cervical squamous epithelium. This study correlated p63 expression with morphologic phenotype and human papillomavirus (HPV) type in a wide range of cervical neoplasms. Two hundred fifty cases of cervical carcinoma, including squamous cell carcinoma (SCCA; n = 178), adenocarcinoma (ADCA; n = 28), adenosquamous carcinoma (ASCA; n = 8), neuroendocrine carcinoma (NECA; n = 15), and other variant or mixed types (n = 21) were studied. Ninety-seven percent of SCCA, 0% of ADCA, and 0% of SCUC showed strong (>75% v <30%) positivity for p63 (P<.001). p63 sharply distinguished SCCA (p63+) from ADCA (p63-), Large-cell, poorly differentiated carcinomas were distinguished as putative glandular (glassy cell) or squamous (lymphoepithelial-like or spindle cell) types based on p63 staining. Eight (73%) of 11 neuroendocrine tumors tested were chromogranin positive; all showed no or low (<30%) levels of p63 immunostaining. Absence of p63 was also associated with a subset of nonneuroendocrine undifferentiated carcinomas. Transitions from squamous to columnar or undifferentiated morphology coincided with loss of p63 expression. A strong association between HPV 16 and p63 positivity was identified because of the colocalization of both within tumors of squamous phenotype. p63 is a powerful marker for squamous differentiation and, when diffusely expressed, excludes a glandular or neuroendocrine differentiation. p63 may be useful for differentiating pure squamous or glandular from adenosquamous carcinomas, tracking shifts in differentiation within tumors, supporting (by its absence) the diagnosis of neuroendocrine carcinomas, and clarifying the spectrum of poorly differentiated carcinomas lacking either squamous or neuroendocrine differentiation.

Endothelial microtubule disruption blocks flow-dependent dilation of arterioles

The cytoskeleton is believed to have an important role in the structural and functional integrity of endothelial cells. The role of the endothelial cytoskeleton, specifically microtubules, in the mediation of flow-induced dilation of arterioles has not yet been studied. Thus the aim of our study was to investigate the role of microtubules in the endothelial mechanotransduction of flow-induced dilation of isolated gracilis arterioles of the rat. The active diameter of arterioles at a constant perfusion pressure (80 mmHg) was approximately 63 microm, whereas their passive diameter (Ca(2+)-free solution) was approximately 119 microm. At a constant pressure, increases in flow of the perfusate solution (from 0 to 10 and from 10 to 20 microl/min) elicited increases in diameter up to approximately 95 microm (approximately a 53% increase). Intraluminal administration of nocodazole at concentrations of 5 x 10(-9) and 5 x 10(-8) M had no discernible effects on the structure of endothelial microtubules or on flow-induced dilation, whereas it disassembled microtubules and eliminated flow-induced dilation at a concentration of 5 x 10(-7) M. At this higher concentration, however, the basal diameter and dilations to acetylcholine (10(-8) M), sodium nitroprusside (10(-7) M), arachidonic acid (5 x 10(-6) M), and prostaglandin E2 (10(-8) M) were unaffected. Colchicine (5 x 10(-7) M) also disassembled microtubules and eliminated flow-induced dilation. We concluded that, in isolated arterioles, the integrity of the endothelial cytoskeleton is essential for the transduction of the shear stress signal that results in the release of endothelial factors evoking dilation.

Computer simulation of temperature changes in a wheat storage bin

A mathematical model describing the transient temperature distribution of grain in a cylindrical storage bin with mixed boundaries is presented and solved using the finite element method. Using the typical meteorological data of a region such as temperate China, temperature changes of wheat in a storage bin are simulated and analysed in detail. Simulated results indicate that high temperature accumulation areas of the grain are in the bin centre and near the bin bottom or at the top surface of the grain throughout the whole year and ventilation under appropriate weather conditions is necessary. This method can be used to develop and evaluate aeration control strategy and reduce the need for chemical treatments of grain during storage.

h-Caldesmon expression effectively distinguishes endometrial stromal tumors from uterine smooth muscle tumors

Distinction of endometrial stromal neoplasms from cellular smooth muscle tumors of the uterus is sometimes difficult. Immunohistochemistry is often not helpful because muscle actins and desmin are expressed in both neoplasms. This study's goal was to determine whether h-caldesmon, a smooth muscle-specific isoform of a calcium, calmodulin, and actin binding protein, could effectively distinguish endometrial stromal tumors from uterine smooth muscle tumors. The authors analyzed immunohistochemical expression in 24 endometrial stromal neoplasms (21 sarcomas and three nodules), 29 leiomyosarcomas, 32 leiomyomas (10 "usual," 14 cellular leiomyoma, and eight "highly cellular" types), 40 myometria, and 25 endometria. h-Caldesmon was diffusely positive in all myometria, leiomyomata, and leiomyosarcomas. Of note, 16 leiomyosarcomas (55%) were positive for h-caldesmon in more than 50% of tumor cells. In five "highly cellular" leiomyomas, h-caldesmon expression was markedly decreased or absent in areas morphologically resembling endometrial stromal tumors, raising the possibility that these tumors may be mixed smooth muscle-endometrial stromal neoplasms. In contrast, h-caldesmon expression was absent in all endometria and endometrial stromal neoplasms apart from accompanying small vessels. Desmin was diffusely positive in all myometria and leiomyomata. The fraction of cells expressing desmin was greater than that of h-caldesmon in only 10% of leiomyosarcomas. Focal desmin expression was also present in eight of 25 (32%) endometria and 12 of 24 (50%) endometrial stromal neoplasms. h-Caldesmon appears to be a more sensitive and specific marker of smooth muscle differentiation in the uterus than desmin and may be a useful tool for distinguishing and classifying uterine mesenchymal tumors.

Identification of envelope glycoproteins H and B homologues of human herpesvirus 7

The genes encoding the envelope glycoprotein H (gH) and gB homologues were identified by sequencing genomic clones of human herpesvirus-7 (HHV-7), strain JI. A gB cDNA clone from HHV-7 strain AL was also identified. The deduced primary translation products of the gH and gB genes are a protein of 690 amino acids, with a predicted mass of 80.4 kD, and a protein of 822 amino acids, with a predicted mass of 93.3 kD, respectively. Both the predicted proteins have the characteristics of transmembrane glycoproteins, containing signal and transmembrane sequence motifs and characterized by the presence of 10 (gH) and 11 (gB) potential motifs for N-glycosylation. Comparison of amino acid sequence of HHV-7 gH and gB with the homologous sequences of the other human herpesviruses reveals closest homology with HHV-6 (38.8% identity for gH, 56.2% identity for the gB). In addition, significant sequence similarity was also observed between the gH and gB of HHV-7 and the homologs encoded by human cytomegalovirus (21.6% identity for gH, 37.6% identity for gB). No significant differences existed between the gB sequence of the two different HHV-7 strains analyzed. The products of the HHV-7 gH and gB expressed transiently in eukaryotic cells were specifically recognized by an HHV-7-reactive human serum in immunofluorescence assays.

Protein and DNA oxidation in spinal injury: neurofilaments--an oxidation target

This study measured the time courses of protein and DNA oxidation following spinal cord injury (SCI) in rats and characterized oxidative degradation of proteins. Protein carbonyl content-a marker of protein oxidation-significantly increased at 3-9 h postinjury and the ratio 8-hydroxy-2-deoxyguanosine/deoxyguanosine-an indicator of DNA oxidation-was significantly higher at 3-6 h postinjury in the injured cords than in the sham controls. This suggests that oxidative modification of proteins and DNA contributes to secondary damage in SCI. Densities of selected bands on coomassie-stained gels indicated that most proteins were degraded. Neurofilament protein (NFP) was particularly evaluated immunohistochemically; its light chain (NFP-68) was gradually degraded in nerve fibers, neuron bodies, and large dendrites following SCI. A mixture of Mn (III) tetrakis (4-benzoic acid) porphyrin (10 mg/kg)-a novel SOD mimetic-and nitro-L-arginine (1 mg/kg)-an inhibitor of nitric oxide synthase-injected intraperitoneally, increased NFP-68 immunoreactivity and the numbers of NFP-positive nerve fibers post-SCI, correlating NFP degradation in SCI to free radical-triggered oxidative damage for the first time. Therefore, blockage of protein and DNA oxidation in the secondary injury stage may improve long-term recovery-important information for development of the SCI therapies.

A study of hemorheological behaviour for patients with Alzheimer's disease at the early stages

To evaluate the change of hemorheological indexes for patients with Alzheimer's disease (AD) at the early stages and to discuss effects of these changes on AD, high shear value of whole blood viscosity (etabh), reduced high shear value of whole blood viscosity (retabh), low shear value of whole blood viscosity (etabl), reduced low shear, value of whole blood viscosity (retabl), KT value of whole blood viscosity, hematocrit (HCT) and blood plasma viscosity (etaP) were measured in 31 patients with probable AD at the early stages and 33 age-matched healthy subjects. There were significant differences of all hemorheological indexes between AD group and control group except HCT. Step discriminant analysis revealed 81.25% of overall group-classified accuracy in a hemorheological discriminant function consisting of etabl, retabl, retabh and HCT. Significant difference of hemorheological indexes existed between AD and age-matched healthy control subjects. The results showed that measurement of hemorheological indexes could be used as one of reference standards of diagnosis in AD.

Spermidine/spermine N1-acetyl transferase activity in rat brain following transient focal cerebral ischemia and reperfusion

The polyamine system is very sensitive to different pathological states of brain and is perturbed after central nervous system (CNS) injury. Spermidine/Spermine N(1)-acetyl transferase (SSAT) is the key enzyme responsible for interconversion of spermine and spermidine to spermidine and putrescine respectively. In the present study, SSAT activity was evaluated in the rat CNS, following transient focal cerebral ischemia and reperfusion. The middle cerebral artery (MCA) was occluded for 2 h in male spontaneously hypertensive rats by an intraluminal suture technique. Animals were sacrificed at 3-24 h reperfusion following the MCA occlusion and SSAT activity was assayed in cortex and striatum. Results showed that SSAT activity was significantly increased at 12 h reperfusion in cortex and at 9, 12 and 18 h reperfusion in striatum following ischemia compared to sham or contralateral controls. These results demonstrate that polyamine catabolism in the rat CNS is altered following MCA occlusion. In the in vitro ischemia study, SSAT activity was evaluated in primary cortical neuronal cultures at 6-24 h re-oxygenation intervals following oxygen-glucose deprivation for 1 h, and the results from this group show that the enzyme activity increased by about 62% (P<0.05) at 24 h re-oxygenation. This study suggests that the increased SSAT activity may contribute to the increase in putrescine during the post-ischemic period.

[Feasibility of using short form 36 in Chinese population]

OBJECTIVE

To explore the feasibility of using the SF-36 in Chinese population.

METHODS

We tested the reliability and validity of the SF-36 in 1603 rural residents, 646 urban residents, 70 high school girls, 122 patients with osteoporosis, and 150 stroke patients.

RESULTS

The reliability and validity of the SF-36 in general were acceptable, however, the reliability and validity varied among different domains and in different populations. The reliability and validity of the domains "limitations in physical activities", "limitations in usual role activities because of physical health problems", "bodily pain", and "general health perception" were better than those of the domains "vitality", "limitations in social activities", "limitations in usual role activities because of emotional problems", and "mental health".

CONCLUSION

The results indicate that we can use the SF-36 in Chinese population, but we have to pay attentions to the variance of the reliability and validity in different populations, especially for the interpretation of the results of the domains related to mental and social functions.

Crystal structure of rat biliverdin reductase

Biliverdin reductase (BVR) is a soluble cytoplasmic enzyme that catalyzes the conversion of biliverdin to bilirubin using NADH or NADPH as electron donor. Bilirubin is a significant biological antioxidant, but it is also neurotoxic and the cause of kernicterus. In this study, we have determined the crystal structure of rat BVR at 1.4 A resolution. The structure contains two domains: an N-terminal domain characteristic of a dinucleotide binding fold (Rossmann fold) and a C-terminal domain that is predominantly an antiparallel six-stranded beta-sheet. Based on this structure, we propose modes of binding for NAD(P)H and biliverdin, and a possible mechanism for the enzyme.