Restricted killer cell immunoglobulin-like receptor repertoire without T-cell receptor gamma rearrangement supports a true natural killer-cell lineage in a subset of sinonasal lymphomas

The cellular lineage of sinonasal T/NK (natural killer) cell lymphoma remains controversial. Lineage assignment is difficult because T cells and NK cells have a similar morphology and surface markers. Consequently, the assignment must depend heavily on the status of T-cell receptor (TCR) rearrangement. A monoclonal TCR rearrangement supports a T lineage; however, a corresponding monoclonality test for NK cells has not yet been established. Each NK cell bears a distinct set of killer cell immunoglobulin (Ig)-like receptors (KIRs) that are randomly distributed over three groups. In principle, restriction of the KIR repertoire signifies a monoclonal or possibly oligoclonal NK-cell proliferation, just as Ig light-chain restriction usually indicates a monoclonal B-cell neoplasm. Using a novel group-specific reverse transcriptase-polymerase chain reaction, we found a restricted KIR repertoire in most sinonasal lymphomas (9 of 10), but only rarely in T-cell lymphomas (2 of 10) or reactive conditions involving T/NK cells (1 of 10). KIR+ sinonasal lymphomas usually lacked a monoclonal TCR-gamma rearrangement pattern, expressed another NK cell receptor, NKG2a, and were usually CD56-positve, cyclin-dependent kinase-6 (CDK6)-positive, CD44-negative, a phenotype already reported to indicate a true NK cell lineage. We conclude that, although sinonasal lymphomas have heterogeneous genotypes and phenotypes, a restricted KIR repertoire without TCR-gamma rearrangement provides preliminary support for the monoclonality hypothesis and can be used for defining a true NK-cell lineage in a subset of sinonasal lymphomas.

Two-photon absorption and nonlinear optical properties of octupolar molecules

Two-photon absorption (TPA) cross sections of four representative series of octupolar molecules are theoretically investigated. The general structure--TPA-property relationship is described by using the effective four-state valence-bond three-charge-transfer model. As the charge-transfer character of the ground electronic state increases due to the strong donors or acceptors, (i) the transition dipole matrix elements between the ground and 2-fold degenerate excited states increase, (ii) the energy gap decreases, and consequently (iii) the TPA transition amplitude monotonically increases. Thus, the design strategy to maximize the TPA cross section of the octupolar molecule is established. On the basis of the four-state model, the first hyperpolarizability of the octupolar molecule is found to be linearly proportional to the TPA cross section. This theoretical relationship is confirmed by using the ab initio calculation results. The Hammett correlation analysis of the TPA cross section and first hyperpolarizability is also presented.

Expression of interleukin-1 beta in lipopolysaccharide stimulated monocytes derived from patients with aneurysmal subarachnoid hemorrhage is correlated with cerebral vasospasm

Cerebral arterial vasospasm is a frequent complication after aneurysmal subarachnoid hemorrhage (SAH). Immunological activation may affect the development of vasospasm. This study measured the cytokines released from lipopolysaccharide-stimulated monocytes of SAH patients. We measured cerebral artery diameters before and after surgery for SAH. The activation index of interleukin-1 beta (IL-1 beta), but not tumor necrosis factor-alpha (TNF-alpha), was higher in patients with symptomatic vasospasm (5.6+/-1.7; n=11) than in patients without (1.8+/-0.4; n=11) (P=0.039). Furthermore, the IL-1 beta activation index was correlated with the degree of the postoperative angiographic vasospasm (correlation coefficient=-0.66, P=0.007). Individual variation in systemic immune activation, measured by monocyte-derived IL-1 beta expression levels after stimulation, may be associated with the development of vasospasm after aneurysmal SAH.

Effects of intravenous insulin-like growth factor-I and insulin administration on insulin-like growth factor-binding proteins in the ovine fetus

The insulin-like growth factors (IGF) are important anabolic hormones in the mammalian fetus; their anabolic actions are potentially modulated by alterations in the IGF-binding proteins (IGFBP). We have previously shown that the nutritional state of the fetus affects both IGF-I and the IGFBP concentrations. The present study was designed to determine the effect of alterations in insulin and IGF-I circulating concentrations on the IGFBPs. Because both insulin and IGF-I elicit decreases in glucose and amino acid concentrations, the concentrations of these substrates were clamped during the hormone infusions. Sixteen ovine fetuses were chronically catheterized at approximately 115 days of gestation, and experimental procedures performed at approximately 130 days of gestation. Insulin, IGF-I or both were infused for an 8-h period. Baseline concentrations of hormones and binding proteins were obtained, and concentrations were also obtained at the end of the infusion. Hepatic IGFBP-1 mRNA expression was also determined. Intravenous infusion of IGF-I significantly increased IGF-I concentrations in plasma in the ovine fetus. Intravenous infusion of insulin inhibited hepatic IGFBP-1 gene expression when amino acids and glucose were clamped. In contrast, intravenous infusion of recombinant human IGF-I (rhIGF-I) enhanced hepatic IGFBP-1 gene expression. Neither insulin nor rhIGF-I treatment had an effect on hepatic IGFBP-3 gene expression. Insulin did not alter plasma IGFBP-1 significantly, but it increased IGFBP-3 in plasma. rhIGF-I increased both IGFBP-1 and IGFBP-3 protein levels in plasma. The responses of IGFBP-1 and IGFBP-3 to increased plasma IGF-I and insulin may serve to protect the fetus from exaggerated anabolic effects and to blunt the hypoglycemic potential of circulating IGFs and insulin.

A comparison of methods for yeast identification including CHROMagar Candida, Vitek system YBC and a traditional biochemical method

BACKGROUND

CHROMagar Candida (CAC) is a new chromogenic medium for the presumptive identification of clinically-important yeast isolates. A yeast biochemical card (YBC), a part of the Vitek system is an automatic method for the identification of clinically-important yeast isolates. We conducted a comparison of these two methods with a traditional biochemical method in order to choose a rapid and accurate technique for yeast identification.

METHODS

All yeast isolates were inoculated onto Sabourand dextrose agar (SDA) and CAC, and incubated at 30 degrees C for 48 hours. All isolates were simultaneously tested using traditional biochemical methods and the yeast biochemical card from the Vitek system.

RESULTS

We evaluated 235 yeast isolates from clinical specimens, including 89 Candida albicans, 47 Candida tropicalis, 43 Candida glabrata, six Trichosporon beigelii, and five Candida krusei in addition to 45 isolates of other yeast species. Isolates were presumptively identified on the basis of colony color and appearance on CAC medium. These observations were compared with a traditional biochemical yeast-identification method and also with YBC from the Vitek system. For five commonly-isolated species (Candida albicans, Candida tropicalis, Candida glabrata, Candida krusei and Trichosporon beigelii), agreement among the CAC medium, YBC method and traditional biochemical method were 98.9% (187/189), 96.3% (182/189), 100% (189/189), respectively.

CONCLUSIONS

From our comparison, the CAC medium is a convenient and economic method to identify five commonly-noted yeast species, and the YBC method warrants a greater cost and requires a longer period of time to obtain reliable results.

Urethral diverticulo-rectal fistula in AIDS

A 41-year-old heterosexual African man was evaluated for persistent urethral discharge, pneumaturia and watery diarrhea. Radiographic and endoscopic procedures established the diagnosis of a rectourethral fistula. The differential diagnosis of an acquired rectourethral fistula and the significance of AIDS are discussed.

Activation of CD14 on circulating monocytes in patients with acute coronary syndrome

BACKGROUND

Increasing evidence supports the involvement of inflammation in acute phase of coronary artery diseases.

METHODS

We analyzed the status of activation of inflammatory cells in 38 patients with acute coronary syndrome, 14 stable angina patients, and 19 control subjects by flow-cytometry. Expression levels of CD14 and the percentage of HLA-DR(+) T-lymphocytes were used as markers of monocyte and T-lymphocytes activation, respectively.

RESULTS

The expression of CD14 on monocytes in acute coronary syndrome patients (mean fluorescence intensity+/-S.D.=158.1+/-77.1) was increased significantly in comparison to control subjects (57.1+/-8.0) and the stable angina group (63.6+/-22.0) (P<0.0001 for both). A significantly higher percentage of HLA-DR positive T-lymphocytes (20.4+/-9.0 vs. 12.7+/-3.7%, P<0.01) was observed in acute coronary syndrome patients in comparison to control subjects. Incubation of whole blood cells with bacterial lipopolysaccharide resulted in a 2.4-fold higher secretion of tumor necrosis factor-alpha in acute coronary syndrome patients than in control subjects (P<0.05). When these markers of activation were measured in acute coronary syndrome patients 6 weeks after medical treatment, a significant reduction both in monocytic CD14 expression and percentage of HLA-DR positive T-lymphocytes (P<0.05 for both) was observed.

DISCUSSION

We observed markedly increased levels of monocytic CD14 expression in ACS patients, which appear to indicate the activated status of monocytes and hyper-responsiveness to external stimuli. The CD14 expression levels decreased as the patients were treated, indicating that the expression of CD14 accurately represents the activation status of monocytes during the acute phase of coronary artery diseases.

A case of testicular tunica albuginea cyst with psammoma body

Cystic testicular masses have been considered rare but due to advances in ultrasonographic technologies their incidence has risen. Many testicular cystic masses are benign but there is a chance of malignancy. Psammoma bodies are found in various malignancies that occur in the genital tract of women but rarely in men. We report a case of testicular tunica albuginea cyst with psammoma bodies.

Doenjang hexane fraction-induced G1 arrest is associated with the inhibition of pRB phosphorylation and induction of Cdk inhibitor p21 in human breast carcinoma MCF-7 cells

Doenjang (fermented soy paste) is a Korean traditional fermented food. In previous studies, we demonstrated that Doenjang extracts exhibited anti-mutagenic and anti-carcinogenic activities. Here we investigated the effects of Doenjang hexane fraction (DHF) on cell cycle progression in the human breast carcinoma MCF-7 cells. Treatment of DHF to MCF-7 cells induced a G1 phase arrest of the cell cycle, which correlated with the accumulation of the hypophosphorylated form of the retinoblastoma protein (pRB) and enhanced association of pRB with the transcription factor E2F-1. After DHF treatment, the expression of D-type cyclins was decreased in a time-dependent manner, but DHF did not affect the levels of cyclin-dependent kinases (Cdks), cyclin E and cyclin A protein. However, the activity of Cdk2 and cyclin E-associated kinase was decreased in a time-dependent manner. The tumor suppressor p53 and Cdk inhibitor p21, a known downstream effector of the p53, and association of p21 with Cdk2 were markedly induced in DHF-treated cells. Taken together, the present results indicate that treatment of MCF-7 cells with DHF induces a significant inhibition of pRB phosphorylation and increase of Cdk inhibitor p21 that appear to be responsible for the observed G1 arrest.

High prevalence of VanB2 vancomycin-resistant Enterococcus faecium in Taiwan

Thirty-six VanB glycopeptide-resistant Enterococcus faecium isolates were collected from patients in five different hospitals in Taiwan. The vancomycin resistance genes were amplified by the long vanB PCR, which amplifies the 6,373-bp vanB gene cluster including the vanR(B2), vanS(B2), vanY(B2), vanW(B2), vanH(B2), vanB2, and vanX(B2) genes. The deduced amino acid sequences were found to be 95 to 98% homologous to those of the vanB1 gene cluster: VanR(B1), 97%; VanS(B1), 97%; VanY(B1), 96%; VanH(B1), 95%; VanB1, 96%; and VanX(B1), 98%. Restriction enzyme analysis of the long vanB PCR products revealed that all 36 isolates had the same vanB2-specific pattern. DNA sequence analysis of the vanB2 gene, which is a D-Ala-D-Lac ligase gene, revealed that none of the 36 sequences were identical to the previously published vanB2 sequence. Thirty-one isolates had 1 nucleotide different from the published vanB2 sequence. The sequences of the other five isolates differed from the published vanB2 sequence by 2 or 3 nucleotides. Four isolates with a low or moderate resistance to vancomycin (MIC = 4 to 32 microg/ml) were found to have the same leucine-to-methionine change at amino acid position 308 of the vanB2 gene. The genomic DNAs of all 36 isolates were digested with SmaI and then typed by pulsed-field gel electrophoresis (PFGE). Eight different PFGE types (I to VIII) were observed, and type I was found to be prevalent in all hospitals examined in this study. This result suggests that intra- and interhospital dissemination of this E. faecium strain has occurred in Taiwan.

Downregulation of phospholipase C delta3 by cAMP and calcium

Four different isoforms of mammalian phospholipase C delta (PLCdelta) have been described. PLCdelta1, the best-understood isoform, is activated by an atypical GTP-binding protein. It has been suggested that it is a calcium signal amplifier. However, very less is known about other subtypes, including PLCdelta3. Therefore, in the present study, we examined the expression of PLCdelta3 in different human tissues. Moreover, the cellular underlying regulation for PLCdelta3 was studied in different cell lines. Our study showed that the mRNA and protein levels differed significantly among human tissues. The human PLCdelta3 gene was composed of 15 exons and 1 putative cAMP response element in the 5'-end promoter region. PLCdelta3 mRNA expression was downregulated by cAMP and calcium in both the human normal embryonic lung tissue diploid WI38 cell line and the glioblastoma/astrocytoma U373 cell line. However, mRNA expression showed no impact by PKC activators or inhibitors. This study shows the human PLCdelta3 expression pattern and is the first report that PLCdelta3 gene expression is downregulation by cAMP and calcium.

BRCA1 mediates ligand-independent transcriptional repression of the estrogen receptor

Mutational inactivation of BRCA1 confers a cumulative lifetime risk of breast and ovarian cancers. However, the underlying basis for the tissue-restricted tumor-suppressive properties of BRCA1 remains poorly defined. Here we show that BRCA1 mediates ligand-independent transcriptional repression of the estrogen receptor alpha (ERalpha), a principal determinant of the growth, differentiation, and normal functional status of breasts and ovaries. In Brca1-null mouse embryo fibroblasts and BRCA1-deficient human ovarian cancer cells, ERalpha exhibited ligand-independent transcriptional activity that was not observed in Brca1-proficient cells. Ectopic expression in Brca1-deficient cells of wild-type BRCA1, but not clinically validated BRCA1 missense mutants, restored ligand-independent repression of ERalpha in a manner dependent upon apparent histone deacetylase activity. In estrogen-dependent human breast cancer cells, chromatin immunoprecipitation analysis revealed the association of BRCA1 with ERalpha at endogenous estrogen-response elements before, but not after estrogen stimulation. Collectively, these results reveal BRCA1 to be a ligand-reversible barrier to transcriptional activation by unliganded promoter-bound ERalpha and suggest a possible mechanism by which functional inactivation of BRCA1 could promote tumorigenesis through inappropriate hormonal regulation of mammary and ovarian epithelial cell proliferation.

Nucleotide sequence and phylogenetic analysis of long terminal repeats of human endogenous retrovirus K family (HERV-K) on human chromosomes

It has been suggested that human endogenous retroviruses K family (HERV-K) has a role in disease, and solitary long terminal repeats (LTRs) of HERV-K have been potentially capable of affecting the expression of closely located genes. Using the human monochromosomes 8, 9, 17, and 18, with specific PCR primers, we identified thirty-four sequences of new HERV-K LTRs. Those LTR elements were analyzed phylogenetically with the human-specific HERV-K LTRs using neighbor-joining and maximum parsimony methods. Clones HKL8-5, HKL9-5, and HKL9-8 are related by more than 99% homology with the human-specific HERV-K LTRs. The HKL9-5 clone on chromosome 9 was 100% identical with the sequences of human-specific LTR, AC002400, on chromosome 16. The findings suggest that there has been recent proliferation, transposition, or chromosomal translocation of HERV-K LTR elements on human chromosomes.

A cofactor of tRNA synthetase, p43, is secreted to up-regulate proinflammatory genes

An auxiliary factor of mammalian multi-aminoacyl-tRNA synthetases, p43, is thought to be a precursor of endothelial monocyte-activating polypeptide II (EMAP II) that triggers proinflammation in leukocytes and macrophages. In the present work, however, we have shown that p43 itself is specifically secreted from intact mammalian cells, while EMAP II is released only when the cells are disrupted. Secretion of p43 was also observed when its expression was increased. These results suggest that p43 itself should be a real cytokine secreted by an active mechanism. To determine the cytokine activity and active domain of p43, we investigated tumor necrosis factor (TNF) and interleukin-8 (IL-8) production from human monocytic THP-1 cells treated with various p43 deletion mutants. The full length of p43 showed higher cytokine activity than EMAP II, further supporting p43 as the active cytokine. p43 was also shown to activate MAPKs and NFkappaB, and to induce cytokines and chemokines such as TNF, IL-8, MCP-1, MIP-1alpha, MIP-1beta, MIP-2alpha, IL-1beta, and RANTES. Interestingly, the high level of p43 was observed in the foam cells of atherosclerotic lesions. Therefore, p43 could be a novel mediator of atherosclerosis development as well as other inflammation-related diseases.

Apoptotic activity of novel bile acid derivatives in human leukemic T cells through the activation of caspases

The therapeutic efficacies of bile acids, such as ursodeoxycholic acid (UDCA) and chenodeoxycholic acid (CDCA), have been widely demonstrated in various liver diseases, suggesting that they might protect hepatocytes against common mechanisms of liver damage. Although they have been shown to prevent apoptotic cell death in certain cell lines, we have previously reported that a novel derivative (HS-1030) of UDCA significantly inhibited cell growth and induced apoptosis in cancer cells. To develop more effective agents, we synthesized several derivatives, named HS-1183, HS-1199 and HS-1200, based on the structure of UDCA and CDCA, and investigated them for anti-proliferative activity in Jurkat cells, a human leukemic T cell line. Whereas UDCA and CDCA had no significant effects on the growth of Jurkat cells in the concentration range tested, both HS-1199 and HS-1200 completely inhibited the cell proliferation, and HS-1183 showed only a weak inhibitory activity. Furthermore, chromatin condensation, DNA ladder formation and proteolytic cleavage of poly(ADP-ribose) polymerase (PARP) were observed after treatment of novel bile acids, indicating the occurrence of apoptotic cell death, which was associated with down-regulation of caspase-3 and -8. The apoptotic manifestations such as PARP cleavage and DNA fragmentation were abolished in the presence of the tripeptide caspase inhibitor zVAD-fmk or the specific caspase-3 inhibitor DEVD-fmk. Our data thus demonstrate that novel bile acid derivatives-induced apoptosis of leukemic T cells is dependent on caspase activation.

Optical peroxide biosensor using the electrically controlled-release technique

An optical biosensor using an electrically controlled-release system was developed for the measurement of peroxide concentration. The electrically controlled-release system consisted of a current-supplying system and a polymer complex by hydrogen bonding between the carboxylic and oxazoline group. The polymer complex was formed below pH 5.0 and was degraded above pH 5.4. The local pH change near the surface of the polymer complex could be controlled by applying the electric current to release an enzyme reaction reagent, 4-hydroxyphenylacetic acid (HPA), in the polymer complex. The releasing rate of HPA was proportional to the electric current applied to the polymer complex. The model of the controlled-release system was proposed to predict the degradation velocity of the polymer complex, which is equivalent to the releasing rate of HPA. The released HPA and analyte, peroxide, flowed into the reactor with the immobilized enzyme and then reacted with the enzyme. The peroxide concentration was measured based on the fluorescence detection of enzyme reaction product, 6,6'-dihydroxy (1,1'-biphenyl) 3,3'-diacetic acid (DBDA). The proposed biosensor had the linear analytical range of 0.025 approximately 1.0 mM with a response time of 20 min, good repeatability, and reproducibility.

Human endogenous retrovirus HERV-W family: chromosomal localization, identification, and phylogeny

A new human endogenous retroviral family (HERV-W) has been described that is related to multiple sclerosis-associated retrovirus sequences that have been identified in particles recovered from monocyte cultures from patients with multiple sclerosis. Using the polymerase chain reaction approach with a human monochromosomal somatic cell hybrid DNA panel, 15 env fragments of the HERV-W family from chromosomes 1, 3, 4, 5, 6, 7, 12, 14, 17, 20, and X were identified and analyzed. These env fragments showed a high degree of nucleotide sequence similarity (91.6-99.6%) to that of HERV-W. Translation of the env fragments showed no frameshift and termination codons by deletion/insertion or point mutation in some clones (W-1-1, W-3-8, W-4-1, W-7-1, W-14-1, W-17-5, W-20-9, and W-X-3). Phylogenetic analysis of the HERV-W family indicates that the HERV-W env fragments divided into five groups through evolutionary divergence in the primate genome. In group IV, a clone (W-12-2) on chromosome 12 shared 100% sequence identity with a clone (W-17-5) on chromosome 17, suggesting either a retrotransposition or a chromosomal translocation in the last 2 to 5 million years.

Genome mining for human cancer genes: wherefore art thou?

In an initial data-mining effort, the draft human genome was searched to find paralogs of known tumor suppressor genes, and for gene arrangements, which are typical of oncogenes, in cancer cells. The results were disappointing, indicating that although knowledge of the human genome will undoubtedly be of great help, other approaches to identify new oncogenes are needed.

The retinoblastoma gene regulates somatic growth during mouse development

Overexpression of the retinoblastoma gene (Rb) in mice leads to the dwarf phenotype. To explore the potential mechanism of Rb effects on the somatic growth, bitransgenic mice with tetracycline-regulated Rb expression were generated, and their phenotypes were compared with those of previously established Rb mouse models. By gestational day 12.5, embryos lacking Rb and those expressing twice the regular amount of Rb are 15% larger and 10-30% smaller, respectively, compared with their wild-type littermates. The dwarf phenotype is associated with increased plasma levels of insulin-like growth factor-I (IGF-I) but not with growth hormone and glucose concentrations. Down-regulation of the Rb transgene expression results in a reduction of the IGF-I plasma concentrations to normalcy and an increase of somatic growth prenatally and postnatally. Consistent with the in vivo results, cells overexpressing Rb require higher thresholds of IGF-I to stimulate proliferation. Thus, Rb plays an integral role for mouse somatic growth and maintenance during ontogenesis, and IGF-I pathway is likely to be a target for such regulation.

Dietary intake of soybean protein and menstrual cycle length in pre-menopausal Singapore Chinese women

BACKGROUND

Intake of soybean protein was associated with a reduced risk of breast cancer in a case-control study. It has also been demonstrated to increase menstrual cycle length in an experimental setting.

OBJECTIVE

To ascertain whether the association of soybean protein intakes with menstrual cycle length persists in an uncontrolled community setting.

DESIGN

Cross-sectional food frequency dietary survey, menstrual cycle survey and prospective collection of menstrual cycle data.

SETTING

A hospital clinic and a nursing college.

SUBJECTS

Two hundred menstruating women.

RESULTS

An association (P = 0.034) of higher intakes of soybean protein with increased menstrual cycle length, as recorded by self report and by prospectively recording three consecutive cycles, was observed. The risk of menstrual cycle length being greater than the median, when comparing the upper quartile (8.7-35.2 g x day(-1)) of soybean intake and the lowest quartile (0.1-3.3 g x day(-1)) was double, and this approached statistical significance (OR = 2.02, 95% CI = 0.88-4.64 and OR = 1.93, 95% CI = 0.82-4.56 for self-reported cycle length and cycle length as recorded by diary, respectively). In terms of the absolute association with cycle length, subjects in the upper quartile of soybean intake demonstrated a cycle length 1-2 days longer than did subjects in the lowest quartile.

CONCLUSIONS

It is likely that the association between dietary intake of soybean protein and length of menstrual cycle prevails in the community setting. This is shown using both self-reported cycle length and cycle length as recorded in a prospective diary.

The retinoblastoma gene: a prototypic and multifunctional tumor suppressor

Genome instability has been implicated in the generation of multiple somatic mutations that underlie cancer. Germline mutation in the retinoblastoma (RB) gene leads to tumor formation in both human and experimental animal models, and reintroduction of wild-type RB is able to suppress neoplastic phenotypes. Rb governs the passage of cells through the G1 phase-restriction point and this control is lost in most cancer cells. Rb has also been shown to promote terminal differentiation and prevent cell cycle reentry. Recent studies implicate Rb in mitotic progression, faithful chromosome segregation, checkpoint control, and chromatin remodeling, suggesting that Rb may function in the maintenance of genome integrity. It is likely that Rb suppresses tumor formation by virtue of its multiple biological activities. A single protein capable of performing multiple antioncogenic functions may be a common characteristic of other tumor suppressors including p53 and BRCA1/2.

RINT-1, a novel Rad50-interacting protein, participates in radiation-induced G(2)/M checkpoint control

Rad50, an structural maintenance of chromosomes (SMC) protein family member, participates in a variety of cellular processes, including DNA double-strand break repair, cell cycle checkpoint activation, telomere maintenance, and meiosis. Disruption of Rad50 in mice leads to lethality during early embryogenesis, indicating its essential function in normal proliferating cells. In addition to its ability to form a complex with the DNA double-strand break repair proteins Mre11 and NBS1, Rad50 may interact with other cellular proteins to execute its full range of biological activities. A novel 87-kDa protein named RINT-1 was identified using the C-terminal region of human Rad50 as the bait in a yeast two-hybrid screen. Human RINT-1 shares sequence homology with a novel protein identified in Drosophila melanogaster, including a coiled-coil domain within its N-terminal 150 amino acids, a conserved central domain of about 350 amino acids, and a C-terminal region of 90 amino acids exhibiting 35--38% identity. The conserved central and C-terminal regions of RINT-1 are required for its interaction with Rad50. While Rad50 and RINT-1 are both expressed throughout the cell cycle, RINT-1 specifically binds to Rad50 only during late S and G(2)/M phases, suggesting that RINT-1 may be involved in cell cycle regulation. Consistent with this possibility, MCF-7 cells expressing an N-terminally truncated RINT-1 protein displayed a defective radiation-induced G(2)/M checkpoint. These results suggest that RINT-1 may play a role in the regulation of cell cycle control after DNA damage.

The expression of HPV-16 E5 protein in squamous neoplastic changes in the uterine cervix

To investigate the expression of human papillomavirus type 16 (HPV-16) E5 protein in squamous neoplastic changes in the uterine cervix, the specific E5 antibody was generated and used to identify the expression of E5 protein in 40 cases of HPV-16-positive tissues and 5 previously identified HPV-negative normal cervical tissues. The results revealed that E5 protein was primarily expressed in the lower third of the epithelium in low-grade squamous intraepithelial lesions (SILs) and throughout the whole epithelium in high-grade SILs. In invasive squamous carcinoma, 60% of HPV-16-infected cancers which contained the episomal viral genome had the E5 gene, and could express E5 protein which was located throughout the whole epithelium. Previously, we documented the expression of type I growth factor receptors [ERBB1/EGFR (epidermal growth factor receptor), ERBB2, ERBB3 and ERBB4] in the full range of cervical neoplasias by immunohistochemistry assay. Hence, in this study, we extensively analyzed the correlation between the expression of E5 protein and the expression of type I growth factor receptors. Among 40 HPV-16- infected cervical neoplasias, we found that the expression of E5 protein was significantly correlated with either the expression of the ERBB1 or the ERBB4 receptor.

Reproducibility of Tl-201 and Tc-99m sestamibi gated myocardial perfusion SPECT measurement of myocardial function

BACKGROUND

We compared the reproducibility of thallium 201 and technetium 99m sestamibi (MIBI) gated single photon emission computed tomography (SPECT) measurement of myocardial function using the Germano algorithm (J Nucl Med 1995;36:2138-47).

METHODS AND RESULTS

Gated SPECT acquisition was repeated in the same position in 30 patients who received Tl-201 and in 26 who received Tc-99m-MIBI. The quantification of end-diastolic volume (EDV), end-systolic volume (ESV), and ejection fraction (EF) on Tl-201 and Tc-99m-MIBI gated SPECT was processed independently with Cedars-Sinai QGS (Quantitative Gated SPECT) software. The reproducibility of the measurement of ventricular function on Tl-201 gated SPECT was compared with that of Tc-99m-MIBI gated SPECT. Correlation between the 2 measurements for volumes and EF was excellent for the repeated gated SPECT studies of Tl-201 (r = 0.928 to 0.986, P <.05) and Tc-99m-MIBI (r = 0.979 to 0.997, P <.05). However, Bland-Altman analysis revealed the 95% limits of agreement (2 SDs) for volumes and EF were narrower by repeated Tc-99m-MIBI gated SPECT (EDV 14.1 mL, ESV 9.4 mL, EF 5.5%) than by repeated Tl-201 gated SPECT (EDV 24.1 mL, ESV 18.6 mL, EF 10.3%). The root-mean-square values of the coefficient of variation for volumes and EF were smaller by repeated Tc-99m-MIBI gated SPECT (EDV 2.1 mL, ESV 2.7 mL, EF 2.3%) than by repeated Tl-201 gated SPECT (EDV 3.2 mL, ESV 3.5 mL, EF 5.2%).

CONCLUSIONS

QGS provides an excellent correlation between repeated gated SPECT with Tl-201 and Tc-99m-MIBI. However, Tc-99m-MIBI provides more reproducible volumes and EF than Tl-201. Tc-99m-MIBI gated SPECT is the preferable method for the clinical monitoring of ventricular function.

Tumor necrosis factor receptor superfamily 12 may destabilize atherosclerotic plaques by inducing matrix metalloproteinases

Immunohistochemical staining of human atherosclerotic plaques revealed expression of the tumor necrosis factor receptor superfamily (TNFRSF) 12 in regions rich in macrophage/foam cells. The role of TNFRSF12 in the functioning of monocytes in relation to atherogenesis was investigated by analysis of cellular events after stimulation of TNFRSF12 in a human macrophage-like cell line, THP-1. Activation of the THP-1 cells on plates coated with monoclonal antibody against TNFRSF12 induced the expression of matrix metalloproteinases (MMPs) -1, -9, and -13. Furthermore, the expression patterns of TNFRSF12 and the MMPs overlapped in atherosclerotic plaques. Signaling of TNFRSF12 may thus contribute to the induction of extracellular matrix degrading enzymes in macrophages.