Optical response of Higgs mode in superconductors at clean limit: formulation through Eilenberger equation and Ginzburg-Landau Lagrangian.

Both macroscopic Ginzburg-Landau Lagrangian and microscopic gauge-invariant kinetic equation suggest a finite Higgs-mode generation in the second-order optical response of superconductors at clean limit, whereas the previous derivations through the path-integral approach and Eilenberger equation within the Matsubara formalism failed to give such generation. The crucial treatment leading to this controversy lies at an artificial scheme that whether the external optical frequency is taken as continuous variable or bosonic Matsubara frequency to handle the gap dynamics within the Matsubara formalism. To resolve this issue, we derive the effective action of the superconducting gap nearTcin the presence of the vector potential through the path-integral approach, to fill in the long missing gap of the microscopic derivation of the Ginzburg-Landau Lagrangian in superconductors. It is shown that only by taking optical frequency as continuous variable within the Matsubara formalism, can one achieve the fundamental Ginzburg-Landau Lagrangian, and in particular, the finite Ginzburg-Landau kinetic term leads to a finite Higgs-mode generation at clean limit. To further eliminate the confusion of the Matsubara frequency through a separate framework, we apply the Eilenberger equation within the Keldysh formalism, which is irrelevant to the Matsubara space. By calculating the gap dynamics in the second-order response, it is analytically proved that the involved optical frequency is a continuous variable rather than bosonic Matsubara frequency, causing a finite Higgs-mode generation at clean limit.

[Preliminary progress in the study of the relationship between COVID-19 infection and partial arterial or venous diseases].

Vascular complications are commonly associated with COVID-19 infection. Increasing reports suggest a close relationship between COVID-19 and venous thromboembolic diseases, including deep vein thrombosis and pulmonary embolism. Furthermore, COVID-19 has been linked to various aortic diseases such as aortic valve stenosis, aortic thrombosis, abdominal aortic aneurysm, aortic dissection, and limb ischemia. Consequently, understanding the causes and treatment of these vascular complications has become a critical aspect of comprehensive COVID-19 management. This article provides a review of aortic diseases and venous thromboembolic diseases that may be associated with COVID-19, aiming to explore potential mechanisms underlying the development of these vascular conditions and discuss strategies for preventing thrombosis in COVID-19 patients.

[The relationship between the characteristics of tears and the progression of Stanford type B aortic dissection after endovascular treatment].

Endovascular treatment of Stanford type B aortic dissection (type B dissection) has been widely used. There will be complications such as aortic dilatation, which will lead to poor prognosis of some patients. With more in-depth researches, it was found that there was a possible correlation between the prognosis of type B dissection and tears, such as the increasing of aortic diameter would be faster with longer tears, and the location of the tear will affect the thrombosis of the false lumen. Studies on hemodynamics have also found that different characteristics of tears of aortic dissection can cause changes in the pressure, blood flow rate and blood capacity in the true and false lumens recently. The hemodynamic changes can be used to predict the prognosis of type B dissection. The main characteristics of tears included the size, position, number of tears, residual tears and stent graft induced new entry. Describing the effect of tear characteristics on the development of type B dissection, can provide the basis for the clinical treatment and further research of type B dissection.

Differential Expression of Integrin ß1 in Two Brain Injury Models of Rats.

ABSTRACT: Objective To study the characteristics of positive expression of integrin ß1 in the rat brain tissue of two kinds of traumatic brain injury models and to explore the feasibility of inferring the mode of traumatic brain injury using the positive expression of integrin ß1. Methods The occipital region of rats was hit by hydraulic impact method and pendulum striking method to produce two closed brain injury models of linear and rotation acceleration respectively, then 120 SD rats were randomly divided into linear acceleration injury group, rotation acceleration injury group, sham operation group and normal control group. Immunohistochemistry staining and Western blotting method were used to detect the positive expression of integrin ß1 in different parts of the brain tissue at 30 min, 3 h, 6 h, 12 h, 3 d and 7 d after rat injury. The data was processed statistically by SPSS 18.0 software. Results The positive expression of integrin ß1 was detected 30 min after brain injury and reached the peak 6 h after brain injury. With the extension of injury time, the expression tended to enhance. At the same time points after injury, the differences in the positive expression of integrin ß1 between the linear acceleration injury group and the rotation acceleration injury group in the occipital strike point and thalamus had no statistical significance （ P>0.05）, but the differences in the expression of integrin ß1 in the frontal lobe and brain stem had statistical significance （P<0.05）. Conclusion The characteristics of positive expression of integrin ß1 in brain tissue can be used to infer the strike point and the manner of injury and has application value for the reconstruction of craniocerebral injury process.

Continuous compression behaviors of selective laser melting Ti-6Al-4V alloy with cuboctahedron cellular structures.

Cellular structures often show fluctuating stresses in compression stress-strain curves. Such fluctuating stresses correspond to strut fractures. In this study, the cellular Ti-6Al-4V alloy with cuboctahedron structure was prepared by selective laser melting. The cuboctahedron cellular structures showed reduced fluctuations in their compressive stress-strain curves after the initial yielding peak. Their moduli were modulated via the porosity of the structure by changing the strut diameter. A compressive modulus of between 1.3 and 4.868 GPa can be achieved by varying the porosity in the cellular structures between 33% and 84%. Both heat treatment and hot isostatic press (HIP) treatment reduced the fracture strength of the struts during compression due to the conversion of the α' martensite phase into the more ductile α +â€¯ß phase. The cellular structure with HIP treatment produced a continuous stress-strain curve during compression, indicating uniform strain distribution behavior. The continuous compressive stress-strain curve can lead to reduced debris formation during compression processes. The deformation showed either bending or stretching mechanisms depending on whether the supports were included along the building direction. The design concepts of cellular structures demonstrated in this study will be valuable in future biomedical applications.

Inhibition of miR-660-5p expression suppresses tumor development and metastasis in human breast cancer.

Breast cancer, which derives from the epithelium of the mammary glands, is one of the most common cancers diagnosed in women globally. To date, the authors of many studies have reported that the deregulation of microRNAs (miRNAs) plays a crucial role in the occurrence, development, and metastasis of tumors. Here, we discovered that miR-660-5p was upregulated in the breast cancer cell lines MCF7 and MDA-MB-231 compared with that in the normal control cell line CCD-1095Sk. We then inhibited the expression of miR-660-5p to investigate its biological function in cancer development, progression, and metastasis. We determined the changes in the levels of expression of transcription factor CP2 (TFCP2) and CDKN1A to further clarify the specific mechanism involved. The results showed that downregulation of miR-660-5p significantly suppressed the proliferation, migration, and invasion of MCF7 breast cancer cell. Moreover, inhibition of miR-660-5p promoted cell cycle G1 arrest and reduced apoptosis in breast cancer cells. The specific mechanism studies confirmed that TFCP2 was a direct downstream target of miR-660-5p. Aberrant expression of miR-660-5p repressed TFCP2 expression, whereas inhibition of miR-660-5p decreased TFCP2 protein expression, which is a vital factor in the downstream signaling pathway. In conclusion, miR-660-5p can regulate the proliferation, migration, and invasion of human breast cancer cells, and is a novel potential therapeutic target for the clinical treatment of breast cancer.

Compensatory Hypertrophy After Living Donor Nephrectomy.

BACKGROUND: Previous studies have shown that kidney volume enhances the estimation of glomerular filtration rate (eGFR) in kidney donors. This study aimed to describe the phenomenon of compensatory hypertrophy after donor nephrectomy as measured on computerized tomographic (CT) scans. METHODS: An institutional Domain Specific Review Board (DSRB)-approved study involved approaching kidney donors to have a follow up CT scan from 6 months to 1 year after surgery; 29 patients participated; 55% were female. Clinical chart review was performed, and the patient's remaining kidney volume was measured before and after surgery based on CT scans. eGFR was determined with the use of the Modification of Diet in Renal Disease equation. RESULTS: Mean parenchymal volume of the remaining kidney for this population (mean age, 44.3 ± 8.5 y) was 204.7 ± 82.5 cc before surgery and 250.5 ± 113.3 cc after donor nephrectomy. Compensatory hypertrophy occurred in 79.3% of patients (n = 23). Mean increase in remaining kidney volume was 22.4 ± 23.2% after donor nephrectomy in healthy individuals. Over a median follow-up of 52.9 ± 19.8 months, mean eGFR was 68.9 ± 12.4 mL/min/1.73 m(2), with 24.1% of patients (n = 7) in chronic kidney disease grade 3. Absolute and relative change in kidney volume was not associated with sex, race, surgical approach, or background of hypertension (P = NS). There was a trend of decreased hypertrophy with increasing age (P = .5; Spearman correlation, -0.12). CONCLUSIONS: In healthy kidney donors, compensatory hypertrophy of the remaining kidney occurs in 79.3% of the patients, with an average increment of about 22.4%. Older patients may have a blunted compensatory hypertrophy response after surgery.

Hot-electron effect in spin relaxation of electrically injected electrons in intrinsic Germanium.

The hot-electron effect in the spin relaxation of electrically injected electrons in intrinsic germanium is investigated by the kinetic spin Bloch equations both analytically and numerically. It is shown that in the weak-electric-field regime with E â‰² 0.5 kV cm(-1), our calculations have reasonable agreement with the recent transport experiment in the hot-electron spin-injection configuration (2013 Phys. Rev. Lett. 111 257204). We reveal that the spin relaxation is significantly enhanced at low temperature in the presence of weak electric field E â‰² 50 V cm(-1), which originates from the obvious center-of-mass drift effect due to the weak electron-phonon interaction, whereas the hot-electron effect is demonstrated to be less important. This can explain the discrepancy between the experimental observation and the previous theoretical calculation (2012 Phys. Rev. B 86 085202), which deviates from the experimental results by about two orders of magnitude at low temperature. It is further shown that in the strong-electric-field regime with 0.5 â‰² E â‰² 2 kV cm(-1), the spin relaxation is enhanced due to the hot-electron effect, whereas the drift effect is demonstrated to be marginal. Finally, we find that when 1.4 â‰² E â‰² 2 kV cm(-1) which lies in the strong-electric-field regime, a small fraction of electrons (≲5%) can be driven from the L to Γ valley, and the spin relaxation rates are the same for the Γ and L valleys in the intrinsic sample without impurity. With the negligible influence of the spin dynamics in the Γ valley to the whole system, the spin dynamics in the L valley can be measured from the Γ valley by the standard direct optical transition method.

Majorana fermions in T-shaped semiconductor nanostructures.

We investigate the Majorana fermions in a T-shaped semiconductor nanostructure with the Rashba spin-orbit coupling and a magnetic field in the proximity of an s-wave superconductor. It is found that the properties of the low-energy modes (including the Majorana and near-zero-energy modes) at the ends of this system are similar to those in the Majorana nanowire. However, very distinct from the nanowire, one Majorana mode emerges at the intersection of the T-shaped structure when the number of the low-energy modes at each end N is odd, whereas neither Majorana nor near-zero-energy mode appears at the intersection for even N. We also discover that the intersection Majorana mode plays an important role in the transport through the above T-shaped nanostructure with each end connected with a normal lead. Due to the presence of the intersection mode, the deviation of the zero-bias conductance from the ideal value in the long-arm limit Ne2/h is more pronounced in the regime of odd N compared to the one of even N. Furthermore, when the magnetic field increases from the regime of odd N to the one of even N + 1, the deviation from the ideal value tends to decrease. This behavior is also very distinct from that in a nanowire, where the deviation always tends to increase with the increase of magnetic field.

Cytomegalovirus infection causes morbidity and mortality in patients with autoimmune diseases, particularly systemic lupus: in a Chinese population in Taiwan.

To investigate the clinical outcome of cytomegalovirus (CMV) infection in febrile hospitalized patients with autoimmune diseases, mostly systemic lupus erythematosus (SLE). Fifty-four febrile patients were analyzed retrospectively. Half were diagnosed as CMV infection, by positive CMV pp65 antigenemia assay. Clinical and laboratory data between two groups were compared. Correlation between laboratory data and SELENA-SLEDAI scores/mortality were analyzed in the CMV infection group. Receiver operating characteristic analysis was performed to determine the cutoff points of different parameters for predicting mortality or morbidity. The CMV infection group received a higher corticosteroid dosage (mean 26.3 mg/day) and a higher percentage of azathioprine use before admission than the non-CMV infection group. In the former, the deceased subgroup had a significantly higher number of infected leukocytes for CMV (shortened as CMV counts, P = 0.013), more cases of bacterial infection (P = 0.090), and a higher SLE disease activity index score (P = 0.072) than the alive subgroup. The CMV infection group had lower lymphocyte count and more positive bacterial infection than the non-CMV infection group did (P = 0.013 and P = 0.027, respectively). A level of 25 CMV particles/5 × 10(5) polymorphonuclear neutrophils (PMN) was the best cutoff point for predicting CMV-associated mortality, with a sensitivity of 75.0% and specificity of 72.2%. Moderate dose (30 mg/day) of prednisolone or azathioprine use predisposes patients with autoimmune diseases to CMV infection with concurrent bacterial infection. In particular, peak CMV counts at 25/5 × 10(5) PMN or low lymphocyte counts predict mortality or morbidity, respectively.

Incidence of complications after transrectal ultrasonography-guided biopsy of the prostate in a local tertiary institution.

INTRODUCTION: This study aimed to evaluate the risk of complications for patients who received periprosthetic nerve block (PPNB) with one percent lignocaine before transrectal ultrasonography (TRUS) biopsy of the prostate. METHODS: From 2008 to 2009, data on 526 consecutive patients who underwent prostate biopsy was prospectively recorded and analysed. 475 (90.3 percent) patients received PPNB with 10 ml of one percent lignocaine (Group 1), which was carried out under TRUS-guidance and prior to biopsy. 51 (9.7 percent) patients received diclofenac (100 mg) intramuscular injections or no analgesia (Group 2). Complications were defined as any adverse effects after biopsy. Serious complications were defined as those requiring hospitalisation or invasive/operative procedures for treatment. RESULTS: At baseline, both groups were comparable. The mean prostate-specific antigen level in Group 1 was higher than that in Group 2 (48.6 +/- 13.8 versus 19.0 +/- 4.3 ng/ml; p-value is 0.04). There was no perioperative mortality. Post-procedural complications were reported in 23.4 percent (n is 111) of patients in Group 1 and 25.5 percent (n is 13) in Group 2 (p-value is 0.27). Serious complications were reported in 2.5 percent (n is 12) and 7.1 percent (n is 3) of Group 1 and 2 patients (p-value is 0.10), respectively. Both univariable and logistic regression revealed age below 65 years and pre-procedure complaints of lower urinary tract symptoms as independent predictors for complications (p-values are 0.02 and 0.006, respectively). CONCLUSION: PPNB with one percent lignocaine is a safe analgesic procedure to perform in patients undergoing TRUS biopsy.

Theory of the spin relaxation of conduction electrons in silicon.

A realistic pseudopotential model is introduced to investigate the phonon-induced spin relaxation of conduction electrons in bulk silicon. We find a surprisingly subtle interference of the Elliott and Yafet processes affecting the spin relaxation over a wide temperature range, suppressing the significance of the intravalley spin-flip scattering, previously considered dominant, above roughly 120 K. The calculated spin relaxation times T1 agree with the spin resonance and spin injection data, following a T(-3) temperature dependence. The valley anisotropy of T1 and the spin relaxation rates for hot electrons are predicted.

Macrophages and abnormal BCL-6 or c-MYC gene expression affect the resistance of peritoneal B cells to induction of hyporesponsiveness.

Our earlier results indicate that peritoneal B cells (PEB cells) were not hyporesponsive to in vitro crosslinking of the immunoglobulin (Ig) with a secondary anti-IgG reagent. In this study, the response of PEB cells was reduced by the same treatment given i.p. PEB cells were only sensitive to anti-IgM hyper-crosslinking in the presence of peritoneal macrophages. This sensitivity was partially reversed by anti-interferon-beta antibody. Elevated BCL-6 with c-MYC gene expression in NZB/W F1 splenic B cells after anti-IgM treatment correlated well with reduction of IgM secretion. On the contrary, PEB cells not sensitive to induction of hyporesponsiveness cause abnormal BCL-6/c-MYC gene expression after challenges. A bigger change of increased BCL-6 gene expression after anti-IgM treatment was seen in PEB cells than in splenic B cells. Higher BCL-2 gene expression in NZB/W splenic B cells than those in NZB/W PEB cells do not prevent hyporesponsiveness in the former. In conclusion, the relationship between BCL-6/c-MYC gene expression and IgM secretion in NZB/W F1 splenic B cells is similar to that of conventional B2 cells. Although PEB cells from wild type strain can be rendered hyporesponsive in vivo in the presence of macrophages, the resistance to hyporesponsiveness of challenged autoimmune NZB/W PEB cells in vivo is probably related to abnormal BCL-6/c-MYC gene expression. These combined findings suggest that autoimmune B1 cells violate the accepted paradigm for expression of differentiation-associated transcription factors in B2 cells.

Effects of meal timing on tumor progression in mice.

Meal timing can reset circadian clocks in peripheral tissues. We investigated the effects of such non-photic entrainment on tumor growth rate. Two experiments involved a total of 61 male B6D2F(1) mice synchronized with an alternation of 12 h of light (L) and 12 h of darkness (D) (LD12:12). Mice were randomly allocated to have access to food ad libitum, or restricted to 4 or 6 h during L or D. Rest-activity and body temperature, two circadian outputs, were monitored with an intra-peritoneal sensor. Glasgow osteosarcoma was inoculated into both flanks of each mouse ten days after meal timing onset. Before tumor inoculation, meal timing during D amplified the 24-h rhythms in rest-activity and body temperature with minimal phase alteration as compared to ad libitum feeding. Conversely, meal timing during L induced dominant 12-h or 8-h rhythmic components in activity, nearly doubled the 24-h amplitude of body temperature and shifted its acrophase (time of maximum) from approximately mid-D to approximately mid-L. Thirteen days after tumor inoculation, mean tumor weight (+/- SEM, mg) was 1503 +/- 150 in ad libitum mice, 1077 +/- 157 in mice fed during D and 577 +/- 139 in mice fed during L (ANOVA, p < 0.0001). Overall survival was prolonged in the mice fed during L (median, 17.5 days, d) as compared with those fed during D (14.5 d) or ad libitum (14 d) (Log Rank, p = 0.0035). The internal desynchronization produced by meal timing during L slowed down tumor progression, an effect possibly resulting from improved host-mediated tumor control and/or altered tumor circadian clocks.

Isolation and characterization of the major form of human MUC18 cDNA gene and correlation of MUC18 over-expression in prostate cancer cell lines and tissues with malignant progression.

Ectopical expression of huMUC18, a cell adhesion molecule in the immunoglobulin gene superfamily, causes a non-metastatic human melanoma cell line to become metastatic in a nude mouse system. To determine if MUC18 expression correlates with the development and malignant progression of prostate cancer, we investigated differential expression of human MUC18 (huMUC18) in normal prostate epithelial cells, prostate cancer cell lines, and prostatic normal and cancer tissues. We cloned and characterized the human MUC18 (huMUC18) cDNA gene from three human prostate cancer cell lines and three human melanoma cell lines. The cDNA sequences from the six human cancer cell lines were identical except differences in one to five nucleotides. The deduced amino acid sequences of the longest ORF were 646 amino acids that were identical in these cDNAs except for one to three amino acid residues. The amino acid sequences of all our huMUC18 cDNA genes are similar to that cloned by other group (GenBank access #M28882) except differences in the same seven amino acids. We conclude that huMUC18 cDNA gene reported here represents the gene product from a major allele. The MUC18 mRNA and protein was expressed in three metastatic prostate cancer cell lines (TSU-PR1, DU145, and PC-3), but not in one non-metastatic prostate cancer cell line (LNCaP.FGC). The expression of huMUC18 in these four cell lines is positively related to their extent of in vitro motility and invasiveness and in vivo metastasis in nude mice. HuMUC18 protein was also expressed at high levels in extracts prepared from tissue sample sections containing high grade prostatic intraepithelial neoplasia (PIN), but weakly expressed in extracts prepared from cultured primary normal prostatic epithelial cells and the normal prostate gland. Immunohistochemical analysis showed that huMUC18 was expressed at higher levels in the epithelial cells of high-grade PIN and prostatic carcinomas, and in cells of a perineural invasion, a lymph node, and a lung metastases compared to that in normal or benign hyperplastic epithelium (BPH). We therefore conclude that MUC18 expression is increased during prostate cancer initiation (high grade PIN) and progression to carcinoma, and in metastatic cell lines and metastatic carcinoma. Increased expression of MUC18 is implicated to play an important role in developing and malignant progression of human prostate cancer. Furthermore, the lacking of predominant cytoplasmic membrane expression of MUC18 appeared to correlate with malignant progression of prostate cancer.

Expression of a human cell adhesion molecule, MUC18, in prostate cancer cell lines and tissues.

BACKGROUND: Over expression of huMUC18, a cell adhesion molecule in the immunoglobulin gene superfamily, causes a non-metastatic human melanoma cell line to become metastatic in a nude mouse system. To determine if MUC18 expression correlates with the malignant progression of prostate cancer, we investigated differential expression of human MUC18 (huMUC18) in normal prostate epithelial cells, prostate cancer cell lines, and prostatic normal and cancer tissues. METHODS: RT-PCR and Western blot analyses were used to analyze the expression of MUC18 mRNA and protein in four human prostate cancer cell lines, cultured primary normal prostate epithelial cells, normal prostate and malignant prostate tissues. Immunohistochemistry was used to determine the expression of MUC18 antigen in prostatic tissues at different stages of malignancy. RESULTS: Human MUC18 mRNA and protein was expressed in three different prostate cancer cell lines (TSU-PR1, DU145, and PC-3), but not in one prostate cancer cell line (LNCaP.FGC). HuMUC18 protein was also expressed at high levels in extracts prepared from tissue sample sections containing high grade prostatic intraepithelial neoplasia (PIN), but weakly expressed in extracts prepared from either cultured primary normal prostatic epithelial cells or the normal prostate gland. Immunohistochemical analysis showed that huMUC18 was expressed at higher levels in the epithelial cells of high-grade PIN and prostatic carcinomas and in cells of a lymph node metastasis compared to that in normal or benign hyperplastic epithelium (BPH). CONCLUSIONS: We therefore conclude that MUC18 is expressed at higher levels in pre-malignant and malignant prostatic epithelium, including metastasis. We suggest that over-expression of MUC18 may be a new marker of human prostate cancer and also implicates its possible role in development and progression of prostate cancer.

[Aedes albopictus: cloning and identification of the acetylcholinesterase gene fragment from the mosquito].

OBJECTIVE: To isolate, clone and identify the acetylcholinesterase (AChE) fragment from the mosquito, Aedes albopictus, in relation to exploring mechanism of insectide resistance. METHODS: The genome DNA extracted from the mosquito was used for degenerate polymerase chain reaction (PCR) and the two pairs of oligonucleotides encoding the highly conserved protein sequences were used as primers. The reaction products were cloned to T-vector and transfected into E. coli JM 109. The replicative form DNA of recombinant vector extracted from E. coli JM 109 through alkalilysis was identified by the methods of digestion with EcoR I and Sal I and PCR. RESULTS: The products of degenerate primers polymerase chain reaction were obtained and the identified clone belongs to the AChE fragment of the mosquito. CONCLUSION: The clone was identified as the AChE fragment of Aedes albopictus.

Fas mediates apoptosis and oxidant-induced cell death in cultured hRPE cells.

PURPOSE: To investigate whether Fas ligand (FasL) and the Fas receptor system mediates apoptosis in cultured human retinal pigment epithelial (hRPE) cells and contributes to oxidant-induced death of hRPE cells. METHODS: Expression of FasL and Fas in cultured hRPE cells was examined by Western blot analysis and flow cytometry. The susceptibility of hRPE cells to Fas-mediated apoptosis was determined by incubating cells with recombinant soluble Fas ligand (sFasL). Characteristics of apoptosis assessed included chromatin condensation, DNA cleavage, and phosphatidylserine exposure. To investigate the possible involvement of Fas-mediated apoptosis in oxidative killing of hRPE cells, the effects of the oxidant tert-butylhydroperoxide (tBH) on the expression of FasL and Fas were studied. The specificity of effects of oxidant was examined using the antioxidants glutathione and N-acetyl-L-cysteine (NAC). The requirement for the Fas pathway in tBH-induced apoptosis was investigated using an antagonistic anti-Fas antibody ZB4 that blocks the interaction between FasL and Fas. RESULTS: Cultured hRPE cells constitutively expressed FasL and Fas. Ligation of Fas receptor with recombinant sFasL triggered apoptosis in hRPE cells. tBH treatment of hRPE cells resulted in increased expression of FasL and Fas. Glutathione and NAC completely abrogated tBH-induced increase in FasL and Fas expression and apoptosis. Blocking FasL and Fas interaction by ZB4 inhibited tBH-induced apoptosis, but only partially. CONCLUSIONS: A functional Fas-mediated apoptotic pathway is present in cultured hRPE cells and can be activated with sFasL or by upregulation of FasL and Fas expression with an oxidant. The incomplete inhibition by blocking antibody indicates that the Fas pathway is involved in oxidant-induced apoptosis, but other triggering mechanisms are also important.

Transcription function of each base pair in the control region of the adenovirus VARNA1 gene.

Eighty-seven mutants with single-base substitution in the control region (from -44 to +70) of the adenovirus VARNA1 gene were generated, including nearly every base pair, to examine the role of DNA sequences within this control region for regulating transcription. The effect of these mutations on transcription of the gene was determined in vitro using cytoplasmic S100 extracts from human KB cells. Mutations at -37T, -35A, -29T, -28A, -25C, -18A, -17A, -16A, -13A, -9C, -8C, and -1C in the 5'-flanking region reduced transcription of the gene. Thus two positive regulatory elements, from -44 to -25 and from -18 to +2, interspersed with a putative negative regulatory element were defined. Furthermore, a distinct A-rich purine stretch in the -18 to +2 element was identified. Point mutations in the pyrimidine-rich sequence immediately upstream of the A block promoter element reduced transcription of the gene. Mutations in the GTGG direct repeats of the A block promoter element drastically decreased transcription. Furthermore, mutations that altered the AT-rich sequence immediately downstream of the A block element to become less AT-rich decreased transcription. Mutations of the base pairs at +43C, +45T, and +51A in the inter-block element moderately reduced transcription efficiency of the gene. Mutations at the central four base pairs, GTTC, of the B block palindrome severely affected transcription. These unique sequence motifs and their exact base pairs were proven to be important for regulating transcription of the VARNA1 gene.

Adenovirus VARNA1 gene B block promoter element sequences required for transcription and for interaction with transcription factors.

We constructed mutants with a deletion of either half of the 18 base-pair B block palindrome in the VARNA1 gene, mutants with different intra-palindromic spacings, a complete set of mutants with single base substitutions, and mutants with double and triple base substitutions in the palindrome. The transcription efficiencies of these mutants were determined in human KB cell-free cytoplasmic S100 extracts. The relative competing strength of each mutant, as determined by a sequential competition experiment, was used to assess each mutant's ability to sequester factors into formation of a stable preinitiation complex. The ability of each mutant to assemble transcriptionally active preinitiation complexes was also determined by direct transcription of the isolated complexes. Finally, the ability of each mutant to interact with the transcription factor(s) TFIIIC and form a distinct gel-resolved complex was also determined. From the results of the above assays, we concluded that the two seemingly identical halves of the palindrome did not contribute equally to transcription, or to assembly of the functional preinitiation complex, nor to interaction with TFIIIC. The anterior half (B1) of the B block palindrome, which is proximal to the A block promoter element, played a stronger role in transcription and in assembly of the functional preinitiation complex than the posterior half (B2) of the palindrome. Consistent with this observation, the point mutations in four base-pairs, GTTC, from +60 to +63 in the anterior half of the B block palindrome, has the most severe effect on transcription. In contrast, we showed that the central sequence and the posterior half (B2) played a stronger role than the anterior half (B1) of the B block palindrome in the interaction of the promoter with TFIIIC. This was corroborated by the observation that base substitutions in the central four base-pair sequence of the palindrome, TCGA, from +62 to +65, had the most severe effect on interaction with TFIIIC, and that mutations in most of the sequences in the posterior half of the B block palindrome had more drastic effects than mutations in the anterior half of the palindrome in this interaction. Furthermore, the spacing between the two halves of the B block palindrome had a drastic effect on the overall transcription efficiency and the interaction of the promoter with TFIIIC, suggesting that the interaction between the two halves of the B block palindrome is not only essential, but also synergistic for the interaction with TFIIIC as well as the assembly of a transcriptionally active preinitiation complex and efficient transcription.