The phase-shift mutation in the glucocorticoid receptor gene: potential etiologic significance of neuroendocrine mechanisms in lupus nephritis

BACKGROUND

Glucocorticoid (GC), a mediator of the hypothalamo-pituitary-adrenal axis, has been found to play an important role in maintaining the stability of immune endo-environment of the body. The pathogenesis of lupus nephritis, an autoimmune disease, is thought to be related to the intrinsic hyposensitivity to GC secreted by adrenal gland, and impairs the regulation of the immuno-neuro-endocrine axis.

METHODS

To test this hypothesis, we examined the response of 39 clinic patients with lupus nephritis to GC and analyzed the molecular structure and function of the GC receptor (GR) on peripheral blood mononuclear cells.

RESULTS

There was no difference in the level of ACTH, GC and ligand affinity of GR between the patients and the controls. The GR number on mononuclear cells of lupus patients was lower than that of the controls. There was no difference in GR number between the patients with heterogeneous response, i.e. sensitive, dependent and resistance, to GC. The analysis of exon 9 of the GC receptor with PCR-amplified single strand conformation polymorphism (PCR-SSCP) method showed the polymorphism in exon 9 of GC receptor in 8 of the 39 lupus nephritis patients. DNA sequence analysis revealed an adenine insertion at the 2439 base pair of the GC receptor gene. This phase-shift mutation caused an additional 20 amino acids being translated into protein of GC receptor.

CONCLUSION

The decreased number of GC receptor and the molecular variation of GR on mononuclear cells could explain the phenomenon of GC resistance, potentially to endogenous GC, which suggested an etiological significance of neuro-endocrine-immune mechanism in lupus nephritis. This may be useful in the design of lupus nephritis therapy.

[Percutaneous transluminal septal myocardial ablation in patients with hypertrophic obstructive cardiomyopathy: immediately and middle-term follow-up results]

OBJECTIVE

To evaluate the immediate and follow-up results of percutaneous transluminal septal myocardial ablation (PTSMA) in patients with hypertrophic obstructive cardiomyopathy (HOCM).

METHODS

15 patients with HOCM refractory to medication successfully underwent PTSMA under myocardial contrast echocardiography.

RESULTS

The left ventricular outflow gradients (LVOTG) were reduced significantly (77.93 +/- 22.00) mm Hg to (14.8 +/- 15.0) mm Hg (P < 0.0001) immediately with a mean decrease of (5.75 +/- 2.87) mm Hg (P < 0.001) in left ventricular end diastolic pressure. The scores of SAM and mitral regurgition During a mean of 8.6 +/- 3.8(6-22) months follow-up, the patients heart function (NYHA) were greatly improved(3.4 +/- 0.5 vs 1.1 +/- 0.4, P < 0.001), and disappearance of angina pectoris, and exercise endurance improvement with steady hemodynamic improvement.

CONCLUSION

PTSMA is effectively non-surgical treatment method for drug-refractory patients with HOCM.

Protective effect of green tea against benzo[a]pyrene-induced mutations in the liver of Big Blue transgenic mice

We assessed the ability of green tea to protect against benzo[a]pyrene (B[a]P)-induced mutations in the liver of lacI transgenic male C57BL/6 Big Blue mice. The mice were given a 2% Japanese green tea hot water extract as their sole source of drinking water for 10 weeks. After 7 weeks, they received a total dose of 150 mg/kg B[a]P. Treatment with B[a]P resulted in a two-fold higher lacI mutant frequency than the untreated controls (8.6+/-0.8 x 10(-5) versus 4.0+/-0.7 x 10(-5), P=0.01). B[a]P increased the frequency of its characteristic mutation (GC-->TA transversions) nearly five-fold, from 0.75 x 10(-5) to 3.7 x 10(-5). In mice treated with green tea, the induced B[a]P mutant frequency decreased by 63%, while GC-->TA transversions were reduced by 54%. Thus, we report evidence that green tea extract significantly suppressed B[a]P-induced mutation by lowering its specific transversion mutation in the lacI transgene in vivo. Further studies will address the correlation between the modulation of metabolic enzymes and the protection against induced mutation by green tea.

Distinguishing between cellular and vasogenic edema in head injured patients with focal lesions using magnetic resonance imaging

Having determined that edema and not vascular engorgement is the major factor leading to traumatic brain swelling, the objective of this study was to determine which type of edema, cellular or vasogenic, is responsible for increased tissue water in patients with focal lesions. Severely head injured patients (GCS 8 or less) were transported to imaging suites for measurement of brain water and apparent diffusion coefficient (ADC) using magnetic resonance technique. Cerebral blood flow by stable Xenon method was also measured in the regions of interest. Brain water was increased significantly in the hemisphere with lesion. The increase in water was associated with reduced ADC signifying a predominant cellular edema. The ADC in the contralateral hemisphere was near normal value. Cerebral blood flow values in the regions of interest were above ischemic levels suggesting that factors other than ischemia are responsible for the cytotoxic swelling in patients with focal injury.

Modeling and analysis of the structure of the thermostable catechol 2,3-dioxygenase from Bacillus Stearothermophilus

The three-dimensional structure of thermostable catechol 2,3-dioxygenase(TC230) from Bacillus Stearothermophilus has been modeled basing on the known x-ray structure of catechol 2,3-dioxygenase(metapyrocatechase) from Pseudomonas putida mt-2, using computer graphics energy minimization techniques. The rationality of the resulting model was validated by Ramachandran plot and Profile-3D. The structure-functionally important residues, such as M++ binding residues and the substrate binding residues, were identified from the model. These residues are candidates for further site-directed mutagenesis experiments. The reason that the thermostability of TC230 is greater than metapyrocatechase(MPC) has been found, which may be due to the specific structure of the TC230 in the C-end mainly.

Crystal structure of R-phycocyanin and possible energy transfer pathways in the phycobilisome

The crystal structure of R-phycocyanin from Polysiphonia urceolata (R-PC-PU) at 2.4 A is reported. The R-PC-PU crystal belongs to space group P4(3)2(1)2 with cell parameters a = 135.1 A, c = 210.0 A, and alpha = beta = gamma = 90 degrees. The structure was determined by molecular replacement. The crystallographic R-factor of the refined model is 0.189 (R(free) = 0.239). Comparison of the microenvironment of chromophore beta 155 in R-PC-PU and in C-PC from Fremyolla diphosiphon (C-PC-FD) reveals that their spectral differences may be caused by their different alpha 28 residues. In the R-PC-PU crystal structure, two (alpha beta)(3) trimers assemble face to face to form a hexamer, and two such hexamers assemble in two novel side-to-side arrangements. Possible models for the energy transfer from phycoerythrin to phycocyanin and from phycocyanin to allophycocyanin are proposed based on several phycobiliprotein crystal structures.

Studies on a medicinal parasitic plant: lignans from the stems of Cynomorium songaricum

Eight phenolic compounds including two new lignan glucopyranosides together with a known alkaloid were isolated from the stems of Cynomorium songaricum RUPR. (Cynomoriaceae). Their chemical structures were elucidated on the basis of spectral and chemical evidence. The chemotaxonomic significance of these metabolites is discussed.

Oxidized low-density lipoprotein downregulates endothelial basic fibroblast growth factor through a pertussis toxin-sensitive G-protein pathway: mediator role of platelet-activating factor-like phospholipids

BACKGROUND

Oxidized LDL (oxLDL) inhibits angiogenesis in part by downregulating endothelial basic fibroblast growth factor (bFGF). To determine the mechanism of the downregulation, we investigated the signal transduction pathway involving potential phospholipid mediators.

METHODS AND RESULTS

Cultured bovine aortic endothelial cells were incubated with PBS (lipoprotein-free control), LDL, or copper oxLDL under serum-free conditions. At 24 hours, oxLDL (50 microg/mL) decreased bFGF mRNA (Northern blot), bFGF protein (Western blot and ELISA), and concomitant DNA synthesis, all by 40% to 50% compared with PBS. LDL had no effect. Pretreating the cells with 100 ng/mL pertussis toxin (PTX) for 18 hours before oxLDL exposure almost completely blocked the inhibitory effects of oxLDL. In contrast, inhibiting other major cellular signal transduction pathways with PD-98059 (mitogen-activated protein kinase kinase inhibitor), HA-1004 (inhibitor of cGMP- and cAMP-dependent protein kinase), or Ro-31-8220 (protein kinase C inhibitor) or chelating intracellular Ca(2+) with BAPTA-AM failed to attenuate any of the oxLDL effects assayed. Addition to the cultures of WEB 2086, a specific antagonist of the PTX-sensitive G protein-coupled platelet-activating factor (PAF) receptor, blocked the action of oxLDL. Whereas PAF dispersed in the culture medium failed to produce oxLDL-like effects, degradation of PAF and PAF-like phospholipids accumulated in oxLDL with a recombinant human PAF acetylhydrolase eliminated the inhibitory effects of oxLDL on bFGF expression and DNA synthesis.

CONCLUSIONS

OxLDL suppresses endothelial bFGF expression and DNA synthesis through a PTX-sensitive heterotrimeric G-protein pathway involving mediator phospholipids similar, but not identical, to PAF.

Preparation and characterization of monolithic polymer columns for capillary electrochromatography

A series of micro-monolithic columns with different porosities were prepared for capillary electrochromatography (CEC) by in-situ copolymerization of butyl methacrylate, ethylene glycol dimethacrylate, and 2-acrylamido-2-methyl-1-propane-sulfonic acid in the presence of a porogen in fused-silica capillaries of 100 microm I.D. Different column porosities were obtained by changing the ratios of monomers to porogenic solvents. Columns were investigated and evaluated under both pressure-driven (high-performance liquid chromatography, HPLC) and electro-driven (capillary electrochromatography, CEC) conditions. Each column exhibited different efficiency and dependency on flow velocity under electro-driven conditions. Abnormally broad peaks for some relatively bulky molecules were observed. Possible explanations are discussed. The differences in column efficiency and retention behavior between the two eluent-driven modes were studied in detail. In addition, other column properties, such as morphology, porosity, stability and reproducibility, were extensively tested.

Protein-RNA interactions in the subunits of human nuclear RNase P

A yeast three-hybrid system was employed to analyze interactions in vivo between H1 RNA, the RNA subunit of human nuclear RNase P, and eight of the protein subunits of the enzyme. The genetic analysis indicates that subunits Rpp21, Rpp29, Rpp30, and Rpp38 interact directly with H1 RNA. The results of direct UV crosslinking studies of the purified RNase P holoenzyme confirm the results of the three-hybrid assay.

Abnormal calcium and protein kinase C-epsilon signaling in hypertrophied atrial tumor myocytes (AT-1 cells)

Cardiac hypertrophy leads to contractile dysfunction and altered hormone responsiveness through incompletely understood mechanisms. Atrial tumor (AT-1) myocytes (AT-1 cells) are a cardiomyocyte lineage that proliferates but hypertrophies when proliferation is prevented with mitomycin C. Because both states maintain a highly differentiated phenotype, AT-1 cells were used to explore the signaling pathways that accompany and/or contribute to hypertrophic cardiomyocyte growth. Mitomycin C-induced AT-1 cell enlargement is associated with a pronounced increase in the amplitude and the duration of both electrically stimulated calcium transients and endothelin receptor-dependent calcium responses. Studies with caffeine indicate that the intracellular pool of releasable calcium is similar in control and hypertrophied AT-1 cells. This agrees with the results of Northern analyses that show similar steady-state levels of transcripts encoding the sarcoplasmic reticulum Ca-ATPase (and higher levels of transcripts encoding the Na+/Ca2+ exchanger) in hypertrophied AT-1 cells, relative to proliferating control cultures. However, immunoblot analyses reveal a marked increase in the expression of protein kinase C (PKC)-epsilon (a critical intermediate in the signaling pathway for endothelin receptor-dependent modulation of intracellular calcium) during AT-1 cell hypertrophy; the abundance of other PKC isoforms is not changed. Collectively, these results identify reciprocal regulation between calcium/PKC signaling and hypertrophic growth. The evidence that AT-1 cell hypertrophy leads to abnormalities in calcium regulation and specific changes in PKC-epsilon expression that alter endothelin receptor responsiveness supports the notion that pathophysiological changes in PKC-epsilon abundance lead to functionally important changes in hormonal modulation of cardiomyocyte function.

[Clinical application of Targis veneers]

OBJECTIVE

The aim of this study was to evaluate the Targis material in the form of veneers.

METHODS

Nineteen patients treated with 91 Targis veneers were involved in this study, and the clinical evaluation on veneers was conducted at the time of recall. The evaluation parameters included marginal adaptation, marginal discoloration, surface texture and color match. The periodontal status of all teeth with veneers was evaluated by gingival bleeding index and plaque index before and after the treatment.

RESULTS

The mean observation period for the veneers was 14.6 months. Four veneers failed due to fracture, three because of debond, one because of discoloration. The cumulative rate of success was 91.2%. There was no significant difference in gingival bleeding index before and after treatment, but the plaque index significantly decreased after the treatment.

CONCLUSION

The clinical results of Targis are satisfactory.

[Clinical observation of the microanatomical relation between pituitary stalk and pituitary adenoma]

OBJECTIVE

To observe the microanatomical relation between the pituitary stalk and pituitary adenoma so as to find practical approach to protect the pituitary stalk during operation.

METHODS

At the level of diaphragm sellae, the laterality of pituitary stalk was assessed in 71 cases by its location to the line connecting the mid-points of tuberculum sellae and dorsum sellae. In 46 cases the level of diaphragma sellae was regarded as the clock dial so as to determine the location by hour of the pituitary stalk.

RESULTS

The laterality of pituitary stalk was observed in 61 cases, among which the pituitary stalk was on the left side in 17 cases, on the right side in 41 cases, and at the posterior middle site in 13 cases. Location by hour was observed in 46 cases, among which 13 cases were at 5 o'clock, 11 at 6 o'clock, 7 at 7 o'clock, 5 at 4 o'clock, 4 at 3 o'clock, 2 at 2 o'clock, 2 at o'clock, and 2 at 11 o'clock respectively.

CONCLUSION

The location of pituitary stalk is related to the direction of growth of tumor in the sella and not related to its extension above the sella. The pituitary stalk can be used as the marker to find normal pituitary tissue.

[Anatomicopathological relation between facial nerve and large vestibular Schwannoma]

OBJECTIVE

To study the anatomicopathological relation between facial nerve and large vestibular schwannoma.

METHODS

Operation by suboccipital retrosigmoid sinus approach was performed on 40 cases with large vestibular schwannoma, During the operation, the anatomicopathological relation between the facial nerve and the vestibular schwannoma was observed directly.

RESULTS

The facial nerve was found to be located ventrally (deep under the tumor), dorsally (over the tumor), at the upper pole of the tumor (near the tentorium cerebelli), at the lower pole of the tumor (near the rear group cranial nerves), or aberrant (unable to be identified because of infiltration of tumor). In 31 cases, mainly with parenchymatous tumor, the facial nerve was flat in shape. In 9 cases, mainly with cystic tumor, the facial nerve was bandlike.

CONCLUSION

The facial nerve varies greatly in neuroanatomy among patients with large vestibular schwannoma. Strengthening of operative monitoring can increase the safety of operation.

Gas production by feces of infants

BACKGROUND

Intestinal gas is thought to be the cause abdominal discomfort in infants. Little is known about the type and amount of gas produced by the infant's colonic microflora and whether diet influences gas formation.

METHODS

Fresh stool specimens were collected from 10 breast-fed infants, 5 infants fed a soy-based formula, and 3 infants fed a milk-based formula at approximately 1, 2, and 3 months of age. Feces were incubated anaerobically for 4 hours at 37 degrees C followed by quantitation of hydrogen (H2), methane (CH4), carbon dioxide (CO2), hydrogen sulfide (H2S), methanethiol (CH3SH), and dimethyl sulfide (CH3SCH3) in the head-space.

RESULTS

H2 was produced in greater amounts by breast-fed infants than by infants in either formula group, presumably the consequence of incomplete absorption of breast milk oligosaccharides. CH4 was produced in greater amounts by infants fed soy formula than by infants on other diets. CO2 was produced in similar amounts by infants in all feeding groups. Production of CH3SH was conspicuously low by feces of breast-fed infants and production of H2S was high by soy-formula-fed infants. CH3SCH3 was not detected. Only modest changes with age were observed and there was no relation between gas production and stool consistency, although stools were more likely to be malodorous when concentrations of H2S and/or CH3SH were high.

CONCLUSIONS

Gas release by infant feces is strongly influenced by an infant's diet. Of particular interest are differences in production of the highly toxic sulfur gases, H2S and CH3SH, because of the role that these gases may play in certain intestinal disorders of infants.

[Effects of Pro229-->Ser and Glu243-->Gly on the characters of thermostable catechol 2, 3-dioxygenase]

In order to investigate the effects of amino acid replacement on the characters of thermostable catechol 2, 3-dioxygenase, two mutants (Pro229Ser and Glu243Gly) of this enzyme were obtained by using the method of PCR random mutagenesis. The wild type thermostable catechol 2, 3-dioxygenase and these two mutants (Pro229Ser, Glu243Gly) were over expressed in E. coli TG1 and purified. The enzymatic characters and thermostability of the wild type enzyme and the two mutants (Pro229Ser, Glu243Gly) were analyzed. The results revealed that the optimum enzymatic temperature of the two mutants were the same as that of the wild type enzyme (60 degrees C) and the Kcat/Km value of Pro229Ser and Glu243Gly (4.89 +/- 0.01 x 10(6) mol-1 s-1 and 5.88 +/- 0.01 x 10(6) mol-1 s-1, respectively) were reduced compared with the wild type enzyme (6.97 +/- 0.01 x 10(6) mol-1 s-1). However, the thermostability of Pro229Ser extremely decreased 10.2 degrees C and the thermostability of Glu243Gly slightly increased 1.5 degrees C. It was proposed that Pro229 played an important role on the thermostability of thermostable catechol 2, 3-dioxygenase.

[Gene rearrangement and p53 expression in defining the nature of angioimmunoblastic lymphadenopathy]

OBJECTIVE

To investigate gene rearrangement and p53 expression in defining the nature of angioimmunoblastic lymphadenopathy.

METHODS

DNA was extracted from paraffin-embedded tissue blocks of 44 angioimmunoblastic lymphadenopathy (AIL) patients and analyzed with polymerase chain reaction (PCR) for IgH and TCRgamma gene rearrangement. Immunohistochemistry staining was used to detect p53 protein expression. Thirty-five cases were followed-up.

RESULTS

12 out of 44 cases (27.3%) showed TCRgamma gene rearrangement and 2 (4.5%) showed IgH gene rearrangement. Rearrangement of both IgH and TCRgamma genes were detected in 2 cases (4.5%). 14 cases (31.8%) showed p53 positive expression, among which 12 showed positive rearrangement and 2 showed negative (P < 0.01). Eight out of 11 patients of positive gene rearrangement died in one year, while only 3 patients were still alive at the eighteenth month of follow-up, three of 24 patients of negative gene rearrangement were found dead at the time of the one year follow-up, while the rest 21 patients were alive and the longest survival time was 96 months.

CONCLUSIONS

Gene rearrangement can define the pathological nature of AIL. The expression of p53 is highly related to gene rearrangement, and thus an important immunological marker in research on AIL.

Purification, crystallization and preliminary X-ray studies of thermostable alkaline phosphatase from Thermus sp. 3041

Thermostable alkaline phosphatase from Thermus sp. 3041 has been expressed in Escherichia coli, purified and crystallized. The crystals belong to space group P2(1)22(1), with unit-cell parameters a = 57.7, b = 69.9, c = 111.5 A. Diffraction data were collected to 2.54 A with a completeness of 91.1% (87.8% for the last shell), an R(merge) value of 0.105 (0.312) and an I/sigma(I) value of 9.5 (3.6).

Cell image segmentation with kernel-based dynamic clustering and an ellipsoidal cell shape model

In this paper, we propose a novel approach to cell image segmentation under severe noise conditions by combining kernel-based dynamic clustering and a genetic algorithm. Our method incorporates a priori knowledge about cell shape. That is, an elliptical cell contour model is introduced to describe the boundary of the cell. Our method consists of the following components: (1) obtain the gradient image; (2) use the gradient image to obtain points which possibly belong to cell boundaries; (3) adjust the parameters of the elliptical cell boundary model to match the cell contour using a genetic algorithm. The method is tested on images of noisy human thyroid and small intestine cells.

[Studies of the active site, thermostability and thermophilicity of the thermostable alkaline phosphatase by site-directed mutagenesis]

Through PCR-mediated mutagenesis, three mutants E68S, S70A and E68SS70A around active site S(69) were obtained. Their enzymatic characteristics was determined. It was found that the specific activity of E68S ascended 8 times while its optional reactive temperature climbed 20 degrees C and its Tm descended 3 degrees C; the specific activity of S70A ascended 1 time while its optional reactive temperature climbed 5 degrees C and its Tm descended 2 degrees C; the specific activity of E68SS70A descended 50% while its optional reactive temperature climbed 5 degrees C and its Tm descended 19 degrees C. These result implied that the amino acids, beside the active site, were contributed not only to enzymatic activity but also to its thermostability and thermophilicity. The work provided the direction for mutation to improve enzymatic specific activity and studying the mechanism of thermostability and thermophilicity.

Physical mapping with automatic capture of hybridization data

MOTIVATION

Contig maps are a type of physical map that show the native order of a set of overlapping genomic clones. Overlaps between clones can be detected by finding common sequences using a number of experimental protocols including hybridization of probes. All current mapping algorithms of which we are aware require that hybridizations be scored using a fixed number of discrete values (typically 0/1 or high/medium/low). When hybridization data is captured automatically using digital equipment, this provides the opportunity for hybridization intensities to be used in map construction. More fine-grained distinctions in the levels of hybridization may be exploited by algorithms to generate more accurate physical maps.

RESULTS

We describe an approach to creating contig maps that uses measured hybridization intensities instead of data scored with a fixed number of discrete values. We describe and compare four algorithms for creating physical maps with hybridization intensities. Simulations using measured intensities sampled from actual data on Aspergillus nidulans indicate that using hybridization intensities rather than data that is automatically scored with respect to threshold values may yield more accurate physical maps.

[Clinical analysis of 68 patients with ruptured sinus of Valsalva aneurysm]

OBJECTIVE

To evaluate the clinical characteristics, diagnosis, treatment and prognosis of ruptured aneurysm of the sinus of Valsalva (ASV).

METHODS

Sixty-eight cases of ruptured ASV treated in our hospital from 1986 to 1998 were retrospectively analyzed.

RESULTS

The ratio of male to female was 1.8:1 in 68 patients (44 males, 24 females). The mean age was (29.5 +/- 10.7) years (8-60 years). The proportion of ruptured aneurysms originating from the right coronary and noncoronary sinus was 79.4% and 20.6% respectively. Sixty-seven point six percent of ASV ruptured into right ventricle and 32.3% into right atrium. The incidence of ventricular septal defect and aortic valve insufficiency was 48.5% and 20.6% respectively. The former only existed in those patients whose ASV originating from the right coronary sinus and rupturing into right ventricles. There was a significant correlation between sudden onset of symptoms and fistulating of ASV into right atrium and a significant difference as compared with those fistulating into right ventricle (P < 0.001). Diagnostic sensitivity and specificity of echocardiography in ruptured ASV was 97.1% and 100% respectively, but the rate of missing subarterial ventricular septal defect was 24.2%. Sixty-seven patients received operation, one died of pulmonary embolism six weeks after operation. Thirty-six patients were followed up, the mean follow-up period was 6.5 years (range 1 to 16 years). Two patients were reoperated for leak of ventricular septal defect and aortic regurgitation. The cardiac function of sixteen patients were found to be of NYHA class I, seventeen of class II and three of class III.

CONCLUSION

Echocardiography in combination with aortography is an accurate diagnostic method for ruptured ASV and the prognosis in majority of the patients operated in time is good.

Mechanisms underlying renoprotection during renin-angiotensin system blockade

Potential determinants of chronic renal disease (CRD) progression were studied in male Munich-Wistar rats subjected to 5/6 nephrectomy and treated with candesartan (Csn; n = 30) or enalapril (Ena; n = 27) from 5 wk postsurgery. Despite control of systolic blood pressure (SBP; 24 wk: Csn = 143 +/- 9; Ena = 148 +/- 8 mmHg), urinary protein excretion rates (U(pr)V) increased over 24 wk (Csn = 92 +/- 10; Ena = 99 +/- 8mg/day). Glomerulosclerosis scores (GS) at 24 wk were similar for Csn (42 +/- 7%) vs. Ena (42 +/- 4%), values close to those of untreated controls at 12 wk (43 +/- 4%). At 24 wk, SBP and UprV correlated strongly with GS, together accounting for 72% of the variance in GS. Renal cortex mRNA levels (determined by competitive RT-PCR) for transforming growth factor (TGF)-beta1 and monocyte chemoattractant protein (MCP)-1 were elevated in Csn and Ena at 12 wk and remained higher at 24 wk vs. sham. Strong correlations were evident among TGF-beta1, MCP-1, and interleukin-1beta and renal injury at 24 wk. Cns and Ena are thus equally effective renoprotective agents in this model. During renin-angiotensin system inhibition, renoprotection is dependent on control of both SBP and UprV. Incomplete suppression of renal cytokine gene expression may also contribute to CRD progression.

Protein-protein interactions with subunits of human nuclear RNase P

A yeast two-hybrid system was used to analyze interactions among the protein subunits of human nuclear RNase P themselves and with other interacting partners encoded in a HeLa cell cDNA library. Subunits hpop1, Rpp21, Rpp29, Rpp30, Rpp38, and Rpp40 are involved in extensive, but weak, protein-protein interactions in the holoenzyme complex. Rpp14, Rpp20, and Rpp30 were found to have strong interactions with proteins encoded in the cDNA library. The small heat shock protein 27, which interacts with Rpp20 in the two-hybrid assay, binds to Rpp20 during affinity chromatography and can be found to be associated with, and enhances the activity of, highly purified RNase P. RNase P activity in HeLa cell nuclei also increases under the stress of heat shock.

Dose-effect relationship of dicentric and ring chromosomes in lymphocytes of individuals living in the high background radiation areas in China

Chromosomes of 39 healthy family members (3 generations from 13 families) living both in the high-level background radiation areas (HBRA) and the control areas (CA) were studied. Cumulative dose from birth to the time of blood sampling was estimated by calculating measured exposure rate in each individual. The cumulative doses ranged 30.9-358.9 and 6.0-59.2 mGy for HBRA and CA, respectively. Peripheral lymphocyte chromosome preparations were made according to our improved method. Dicentric and ring chromosomes (Dic + Rc) were scored in average 2,527 cells per individual in HBRA and 2,694 cells in CA under a microscope equipped with an automated stage. A positive correlation between Dic + Rc and age was found in HBRA, while no such dose relationship was clear in CA. The frequency of Dic + Rc linearly increases over lifetime due to chronic low dose exposure and it is likely that the activation of repair enzymes is not triggered in the present HBRA. Threshold dose (rate) of the induction of chromosome aberrations, if any, is below the present dose (rate) level.

Proinflammatory gene expression and macrophage recruitment in the rat remnant kidney

BACKGROUND

Macrophage (Mphi) infiltration may contribute to chronic renal injury. We therefore sought to examine the expression of genes associated with Mphi recruitment in the rat remnant kidney model.

METHODS

Male Munich Wistar rats underwent 5/6 nephrectomy or sham operation (SHM, N = 18) and received no treatment (VEH, N = 18), enalapril 100 mg/L (ENA, N = 18), or candesartan 70 mg/L (CSN, N = 24) in drinking water. Competitive, quantitative reverse transcription-polymerase chain reaction was used to determine renal cortex mRNA levels for cell adhesion molecules vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1), the Mphi chemoattractant monocyte chemoattractant protein-1 (MCP-1), Mphi products interleukin-1beta (IL-1beta) and tumor necrosis factor-alpha (TNF-alpha), and the profibrotic cytokine transforming growth factor-beta1 (TGF-beta1), at intervals post-nephrectomy.

RESULTS

Glomerular and interstitial Mphi infiltration in VEH rats was associated with an early (4 week) and sustained rise in MCP-1 and TGF-beta1 mRNA levels. Progressive increases in ICAM-1, VCAM-1, IL-1beta, and TNF-alpha expression followed at 8 and 12 weeks. Immunostaining in VEH rats localized TGF-beta1 to glomeruli, tubules, and interstitium; MCP-1 to tubules and interstitial cells; ICAM-1 to glomeruli; and IL-1beta and TNF-alpha to tubules and interstitial cells. At 12 weeks, both treatments normalized systolic blood pressure (ENA, 105 +/- 6; CSN, 97 +/- 3 mm Hg) and the urinary protein excretion rate (ENA, 8.4 +/- 0.9; CSN, 5.7 +/- 0.8 mg/day), prevented renal injury (focal and segmental glomerulosclerosis: ENA, 3.3 +/- 0.9; CSN, 1.3 +/- 0.4%), and suppressed Mphi infiltration and cytokine expression (with the exception of TNF-alpha) to near SHM levels.

CONCLUSIONS

These findings support the hypothesis that the coordinated up-regulation of several molecules regulating Mphi recruitment and activation is a fundamental response to renal mass ablation and is dependent on an intact renin-angiotensin system. We speculate that these responses may play a role in the pathogenesis of the ensuing glomerulosclerosis and tubulointerstitial fibrosis.

Stochastic heuristic algorithms for target motif identification (extended abstract)

Target motifs are motifs that are "close" to one or more substrings in each sequence in one given set of sequences but are far from every substring in another given set of sequences. Target motifs have pharmaceutical applications; unfortunately, the problem of identifying target motifs is NP-hard and is thus unlikely to have efficient optimal solution algorithms. In this paper, we propose a set of simple modifications to the Gibbs Sampling heuristic for finding motifs which allows this heuristic to detect target motifs. We also present the results of several experiments relative to both simulated and real datasets which suggest that this modified heuristic is good at detecting target motifs under a variety of conditions.

[Progress in researches on anti-tumor agent L-asparaginase for treatment of leukemia]

L-asparaginase is a very effective anti-tumor agent. To take the most advantage of enzyme treatment method, the natural L-asparaginase could be chemically modified, entrapped or immobilized into/onto other carriers. The extracorporeal shunt system with immobilized enzyme reactor deserves to receive special attention. It provides an entirely new idea for leukemia treatment and is proved to be very prospective in the future leukemia cure.

Intestinal blood loss during cow milk feeding in older infants: quantitative measurements

OBJECTIVE

To determine the response, in terms of fecal hemoglobin excretion and clinical symptoms, of normal 9 1/2-month-old infants to being fed cow milk.

DESIGN

Longitudinal (before-after) trial in which each infant was fed formula for 1 month (baseline) followed by 3 months during which cow milk was fed.

SETTING

Healthy infants living in Iowa City, Iowa, a town with a population of about 60,000.

MAIN OUTCOME MEASURES

Hemoglobin concentration in spot stools, 96-hour quantitative fecal hemoglobin excretion, stool characteristics, feeding-related behaviors, and iron nutritional status.

RESULTS

Fecal hemoglobin concentration during formula feeding (baseline) was higher than previously observed in younger infants. Nine of 31 infants responded to cow milk feeding with increased fecal hemoglobin concentration. Fecal hemoglobin concentration (mean +/- SD) of the 9 responders rose from 1,395 +/- 856 microg/g of dry stool (baseline) to 2,711 +/- 1,732 microg/g of dry stool (P=.01). The response rate (29%) was similar to that in younger infants, but the intensity of the response was much less. Quantitative hemoglobin excretion was in general agreement with estimates based on spot stool hemoglobin concentrations. Cow milk feeding was not associated with recognizable changes in stool characteristics, nor were there clinical signs related to fecal blood loss. Iron status was similar, except that after 3 months of cow milk feeding responders showed lower (P= .047) ferritin concentrations than nonresponders.

CONCLUSIONS

Cow milk-induced blood loss is present in 9 1/2-month-old infants but is of such low intensity that its clinical significance seems questionable. Nevertheless, infants without cow milk-induced blood loss were in better iron nutritional status than infants who showed blood loss.

Fournier gangrene associated with Crohn disease

A 17-year-old boy presented with Fournier gangrene associated with previously undiagnosed Crohn ileocolitis. Fournier gangrene was managed by débridement, broad-spectrum antibiotics, and hyperbaric oxygen. A diverting ileostomy was performed before skin grafting and scrotal reconstruction. Microscopy of a full-layer surgical sample from the terminal ileum revealed granulomas with multinucleated histiocytes, consistent with Crohn disease. Crohn disease was treated with mesalamine, metronidazole, 6-mercaptopurine, and infliximab. The patient was discharged on hospital day 32. At 6-month follow-up, reconstruction of his scrotum had completely healed. Ostomy output was normal.

[Effect of irradiation on the shelf-life of aquatic products]

The effect of irradiation at doses of 0-10 kGy on the shelf-life of aquatic products was determined. The results showed that irradiation could not prolong the shelf-life of aquatic products kept at 25 degrees C. While the aquatic products were kept at refrigerator (4 degrees C), the irradiation could prolong the shelf-life and effectively reduce the total aerobic plate count. Irradiation could effectively reduce the number of coliform to less than 300/kg and eliminate Shigella shigae, Salmonella and Vibrio parahaemolyticus inoculated on shrimp, needle fish and crucian. A dose of 2.5 kGy could delay the rising of total volatile basal nitrogen in samples.

[Blood-purification characteristics of immobilized L-asparaginase by mathematical model]

Plasma was purified by immoblized L-asparaginase column. The predicted results were in good agreement with the experimental data, which indicated that the mathematical model was suitable for the mass transfer of blood purification.

Cow's milk and intestinal blood loss in late infancy

OBJECTIVES

Young infants commonly show occult intestinal blood loss when fed cow's milk, but in older infants blood loss may be less common. This study examined intestinal blood loss in response to cow's milk feeding in normal 7(1/2)-month-old and 12-month-old infants.

STUDY DESIGN

Infants (n = 62) were fed formula for 1 month and then pasteurized cow's milk for 2 months. Stools were collected for quantitative determination of hemoglobin. Iron nutritional status was assessed.

RESULTS

Infants fed cow's milk from 7(1/2) months of age showed a significant increase in guaiac-positive stools and in stool hemoglobin concentration. These effects were largely limited to those infants who had been breast fed early in life. Infants fed cow's milk from 12 months of age at baseline had greater stool hemoglobin concentrations than 7(1/2)-month-old infants, but cow's milk produced no significant increase. In neither age group did cow's milk affect iron nutritional status.

CONCLUSION

The response to cow's milk is attenuated in infants aged 7(1/2) months compared with younger infants. By 12 months of age, the response has disappeared entirely. We conclude that the gastrointestinal tract of healthy infants gradually loses its responsiveness to cow's milk.

[Lateral approaches for treatment of petroclival region tumor]

OBJECTIVE

To summarize the operation experience of resecting petroclival region tumors by lateral approaches.

METHODS

(1) Ameliorate pterion approach; (2) temporal-occipital transtentorial-transpetrous approach; (3) transpetrous combined with supratentorial and infratentorial presigmoid approach; (4) far lateral transcondylar approach were applied for 61 patients with petroclival region tumor.

RESULTS

Of the 61 tumors studied, 54 were completely resected, 6 were nearly complete and 1 was subtotally resected. No patient died in this group, 37 patients were followed up, and all showed satisfying results. 45% of the patients had CNs deficit, with III, VI, V, VIII, IX, X, XII nerve deficits most commonly seen.

CONCLUSION

Lateral approaches are recommended for total resection of petroclival region tumors. HoVDever the operative techniques are complex and potential risks of morbidity exist.

beta-Siloxy unsaturated nitriles: stereoselective cyclizations to cis- and trans-decalins

[formula: see text] beta-Siloxy unsaturated nitriles are excellent precursors to enolate and nitrile anions that cyclize to cis- and trans-decalins, respectively. The stereoelectronic requirements of endocyclic enolates and exocyclic nitrile anions are complementary, providing cis- and trans-decalins from a common intermediate. This cyclization allows the synthesis of diastereomeric cis- and trans-decalins containing a contiguous array of quaternary-tertiary-quaternary stereocenters.

[Transpetrosal presigmoid approach for removal of giant petroclival tumors]

OBJECTIVE

To discuss the operative technique, advantage and postoperative complications in 41 patients with giant petroclival tumors treated with the supra- and infratentorial transpetrousal presigmoid approach.

METHODS

Clinical data were obtained from the review of charts and radiographic images of the 41 patients after operation with temporo-occipotal free osseous flap, partial petrosectomy and mastoidectomy were performed around the labyrinth. The semicircular canals, cochlea and tympanic cavity were protected during the operation. After the super petrous was ligated and cut off, the petroclival region in front of the sigmoid sinus was exposed.

RESULTS

In the 41 patients 20 had meningiomas, 20 epidermoid cysts, and one schwannoma. Total resection was performed in 34 patients, subtotal resection in 16, and greater partial resection in one. Major postoperative complications included temporal aphasia (10 patients), cerebral edema (6), brain stem infarct (2), IIIth, VIIth, VIth and posterial group cranial nerves palsies (16, 16, 8, 6 respectively), and cerebrospinal fluid leakage (4 cases).

CONCLUSIONS

This approach can expose sufficiently the petroclival region. It can also reveal the area of adjacent sella, interpeduncular and formen magnum, and homolateral III-XIIth cranial nerves. The postoperative complications may be related to operative techniues and tumorous characteristics.

[Quantitative determination of 3-nitropropionic acid by HPLC]

A reversed-phase liquid chromatographic method to determine the concentration of 3-nitropropionic acid (3-NPA) in the culture medium with Aspergillus oryzae was developed. The culture medium samples were extracted with ethyl acetate. The analytic column was Hypersil C18 and the mobile phase was CH3CN/KH2PO4(0.02 mol/L, pH 3.0) (1/3, v/v). The sample was detected at UV210 nm. The detection limit of this method was at 10 micrograms/kg level and recoveries were 90.1%-98.0.

An algorithmic approach to multiple complete digest mapping

Multiple Complete Digest (MCD) mapping is a method of determining the locations of restriction sites along a target DNA molecule. The resulting restriction map has many potential applications in DNA sequencing and genetics. In this work, we present a heuristic algorithm for fragment identification, a key step in the process of constructing an MCD map. Given measurements of the restriction fragment sizes from one or more complete digestions of each clone in a clone library covering the molecule to be mapped, the algorithm identifies groups of restriction fragments on different clones that correspond to the same region of the target DNA. Once these groups are correctly determined the desired map can be constructed by solving a system of simple linear inequalities. We demonstrate the effectiveness of our algorithm on real data provided by the Genome Center at the University of Washington.

Identification of neural circuits by imaging coherent electrical activity with FRET-based dyes

We show that neurons that underlie rhythmic patterns of electrical output may be identified by optical imaging and frequency-domain analysis. Our contrast agent is a two-component dye system in which changes in membrane potential modulate the relative emission between a pair of fluorophores. We demonstrate our methods with the circuit responsible for fictive swimming in the isolated leech nerve cord. The output of a motor neuron provides a reference signal for the phase-sensitive detection of changes in fluorescence from individual neurons in a ganglion. We identify known and possibly novel neurons that participate in the swim rhythm and determine their phases within a cycle. A variant of this approach is used to identify the postsynaptic followers of intracellularly stimulated neurons.

Crystal structure of allophycocyanin from red algae Porphyra yezoensis at 2.2-A resolution

The crystal structure of allophycocyanin from red algae Porphyra yezoensis (APC-PY) at 2.2-A resolution has been determined by the molecular replacement method. The crystal belongs to space group R32 with cell parameters a = b = 105.3 A, c = 189.4 A, alpha = beta = 90 degrees, gamma = 120 degrees. After several cycles of refinement using program X-PLOR and model building based on the electron density map, the crystallographic R-factor converged to 19.3% (R-free factor is 26.9%) in the range of 10.0 to 2.2 A. The r.m.s. deviations of bond length and angles are 0.015 A and 2.9 degrees, respectively. In the crystal, two APC-PY trimers associate face to face into a hexamer. The assembly of two trimers within the hexamer is similar to that of C-phycocyanin (C-PC) and R-phycoerythrin (R-PE) hexamers, but the assembly tightness of the two trimers to the hexamer is not so high as that in C-PC and R-PE hexamers. The chromophore-protein interactions and possible pathway of energy transfer were discussed. Phycocyanobilin 1alpha84 of APC-PY forms 5 hydrogen bonds with 3 residues in subunit 2beta of another monomer. In R-PE and C-PC, chromophore 1alpha84 only forms 1 hydrogen bond with 2beta77 residue in subunit 2beta. This result may support and explain great spectrum difference exists between APC trimer and monomer.

Structure and function of chromophores in R-Phycoerythrin at 1.9 A resolution

The crystal structure of R-Phycoerythrin (R-PE) from Polysiphonia urceolata has been refined to a resolution of 1.9 A, based on the atomic coordinates of R-PE determined at 2.8 A resolution, through the use of difference Fourier method and steorochemistry parameters restrained refinement with model adjustment according to the electron density map. Crystallographic R-factor of the refined model is 0.195 (Rfree = 0.282) from 8-1.9 A. High resolution structure of R-PE showed precise interactions between the chromophores and protein residues, which explained the spectrum characteristic and function of chromophores. Four chiral atoms of phycourobilin (PUB) were identified as C(4)-S, C(16)-S, C(21)-S, and C(20)-R. In addition to the coupling distances of 19 A to 45 A between the chromophores which were observed and involved in the energy transfer pathway, high resolution structure of R-PE suggested other pathways of energy transfer, such as the ultrashort distance between alpha140a and beta155. It has been proposed that aromatic residues in linker proteins not only influence the conformation of chromophore, but may also bridge chromophores to improve the energy transfer efficiency.

The thrombin receptor elevates intracellular calcium in adult rat ventricular myocytes

While there is evidence that thrombin receptor activation leads to contractile dysfunction and induces arrhythmias in ischemic/reperfused cardiac tissue, thrombin is variably reported to modulate intracellular calcium in cardiomyocytes. The present study demonstrates that thrombin receptor activation leads to a rise in intracellular calcium in adult ventricular myocytes and serves to reconcile previous discrepant findings. The thrombin receptor-derived agonist peptide (SFLLRN, a portion of the tethered ligand created by thrombin's proteolytic actions) increases cytosolic calcium and twitch amplitude in cardiomyocytes isolated from adult ventricles. The truncated control peptide FLLRN has no effect, establishing that the response to SFLLRN results from a specific agonist peptide-receptor interaction. However, the response to SFLLRN occurs only at high agonist peptide concentrations and thrombin itself is inactive. This result is not compatible with an action of SFLLRN at a distinct protease-activated receptor (PAR-2; which is activated by SFLLRN, but not by thrombin), since SLIGRL (a ligand which is selective for PAR-2, but not the thrombin receptor) has no effect. Rather, the enzyme-based cell isolation procedure may partially cleave the thrombin receptor and influence cell responses, since concentrations of SFLLRN which are sub-threshold in enzymatically disaggregated myocytes significantly increase the force of isometric contraction of intact rat papillary muscles. These studies provide the first evidence that thrombin receptor activation leads to a change in intracellular calcium and a positive inotropic response in adult ventricular myocardium.

[Microsurgical anatomy of far-lateral transcondylar approach]

OBJECTIVE

To supply the far-lateral transcondylar approach with some basic microsurgical anatomy and to protect vital structure.

METHOD

We examined 10 cadveric adult heads and 10 dry skulls.

RESULTS

Mastoid process, jugular fossa, and occipital condyle were important signs. Inferior occipital triangle was formed by muscle rectus capitis posterior major, muscle oblique capitis superior, and muscle oblique capitus inferior, the important mark for distinguishing vertebral artery. Abdundant venous plexus around vertebral artery was the important bleeding source during operation.

CONCLUSION

The aforementioned anatomic landmarks assist in localization, protection of vital structures.

[Correlation study of high-resolution CT with pathologic finding of solitary small lung nodules]

OBJECTIVE

To correlate high resolution CT(HRCT) with pathologic findings and to evaluate the capability of HRCT versus conventional CT(CCT) to provide informations for accurate diagnosis of solitary small lung nodules.

METHODS

Seventy-three cases (75 nodules) of solitary lesions in the lung less than 3 cm in diameter were examined with HRCT (64 cases had CCT) before surgery and correlated with histo-pathologic findings.

RESULTS

In the 37 proven carcinoma, on HRCT, the lesions were round and oval in shape (34), deeply lobulated(28), with serrated margin(33), thin spiculation(37), air alveologram(19), and air bronchogram (10). Histologically, the tumor showed irregular growth pattern with interstitial fibrous proliferation and intra-tumoral residual air-containing spaces in alveoli and bronchioles. Intratumoral fat or calcification, satellate lesions, thick or long spicules, moderate or marked pleural adhesions, scallop-shaped contour were the common findings of benign lesions. HRCT was significantly superior to CCT in the assessment of the intra-structure, contour and margin of the lesion.

CONCLUSION

HRCT is recommended routinely for the evaluation of solitary small pulmonary nodules.

Membrane-permeant esters of phosphatidylinositol 3,4,5-trisphosphate

Phosphoinositide 3-OH kinases and their products, D-3 phosphorylated phosphoinositides, are increasingly recognized as crucial elements in many signaling cascades. A reliable means to introduce these lipids into intact cells would be of great value for showing the physiological roles of this pathway and for testing the specificity of pharmacological inhibitors of the kinases. We have stereospecifically synthesized di-C8-PIP3/AM and di-C12-PIP3/AM, the heptakis(acetoxymethyl) esters of dioctanoyl- and dilauroylphosphatidylinositol 3,4,5-trisphosphate, in 14 steps from myo-inositol. The ability of these uncharged lipophilic derivatives to deliver phosphatidylinositol 3,4,5-trisphosphate across cell membranes was demonstrated on 3T3-L1 adipocytes and T84 colon carcinoma monolayers. Insulin stimulation of hexose uptake into adipocytes was inhibited by the kinase inhibitor wortmannin and was largely restored by di-C8-PIP3/AM, which had no effect in the absence of insulin. Thus phosphatidylinositol 3,4,5-trisphosphate or a metabolite was necessary but not sufficient for stimulation of hexose transport. In T84 epithelial monolayers, di-C12-PIP3/AM mimicked epidermal growth factor in inhibiting chloride secretion and potassium efflux, suggesting that phosphatidylinositol 3,4, 5-trisphosphate was sufficient to modulate these fluxes and mediate epidermal growth factor's action.

Differential regulation of astrocytic mRNAs in the rat striatum after lesions of the cortex or substantia nigra

This study evaluates the time course of expression of three astrocytic mRNAs, glial fibrillary acidic protein (GFAP), apolipoprotein E (ApoE), and clusterin, in the rat striatum (ST) following a unilateral lesion of either the cortex (CX) or the substantia nigra (SN), using Northern blot and in situ hybridization analyses. We found that while there was a time-dependent increase in astrocytic GFAP mRNA in the deafferented ST following both the CX and the SN lesions, the time course of the response was different between the two lesion paradigms. Specifically, the increase in GFAP mRNA in striatal astrocytes after the SN lesion was rapid and transient returning to control levels by 10 days postlesion, while the response was long lasting and remained increased until at least 27 days after the CX lesion. In addition, the mRNA response for both ApoE and clusterin was differentially regulated in response to the two lesions. Specifically, both clusterin and ApoE mRNAs were rapidly increased in the ST following the CX lesion while both mRNAs remained unchanged following the SN lesion. Data from this study extend information derived from previous investigations on the multifunctional role of astrocytes in the response to brain injury. Specifically, our data support the notion that while the time course of the GFAP response in striatal astrocytes may vary between lesion paradigms, the upregulation of GFAP is part of a generalized response of reactive astrocytes to diverse brain injuries. By comparison, upregulation of the mRNAs for the lipoproteins clusterin and ApoE are lesion specific and may play a role in the transport of recycled myelin lipids from dying axons to actively growing axons and dendrites in reactive synaptogenesis.

D-myo-Inositol 1,4,5,6-tetrakisphosphate produced in human intestinal epithelial cells in response to Salmonella invasion inhibits phosphoinositide 3-kinase signaling pathways

Several inositol-containing compounds play key roles in receptor-mediated cell signaling events. Here, we describe a function for a specific inositol polyphosphate, D-myo-inositol 1,4,5,6-tetrakisphosphate [Ins(1,4,5,6)P4], that is produced acutely in response to a receptor-independent process. Thus, infection of intestinal epithelial cells with the enteric pathogen Salmonella, but not with other invasive bacteria, induced a multifold increase in Ins(1,4,5,6)P4 levels. To define a specific function of Ins(1,4,5,6)P4, a membrane-permeant, hydrolyzable ester was used to deliver it to the intracellular compartment, where it antagonized epidermal growth factor (EGF)-induced inhibition of calcium-mediated chloride (Cl-) secretion (CaMCS) in intestinal epithelia. This EGF function is likely mediated through a phosphoinositide 3-kinase (PtdIns3K)-dependent mechanism because the EGF effects are abolished by wortmannin, and three different membrane-permeant esters of the PtdIns3K product phosphatidylinositol 3,4,5-trisphosphate mimicked the EGF effect on CaMCS. We further demonstrate that Ins(1,4,5,6)P4 antagonized EGF signaling downstream of PtdIns3K because Ins(1,4,5, 6)P4 interfered with the PtdInsP3 effect on CaMCS without affecting PtdIns3K activity. Thus, elevation of Ins(1,4,5,6)P4 in Salmonella-infected epithelia may promote Cl- flux by antagonizing EGF inhibition mediated through PtdIns3K and PtdInsP3.