The association of allogeneic blood transfusion and the recurrence of hepatic cancer after surgical resection.

There is conflicting evidence whether allogeneic blood transfusion influences survival or cancer recurrence after resection of hepatocellular cancer. We followed up 1469 patients who had undergone hepatocellular resection for a median (IQR [range]) of 45 (21-78 [0-162]) months, of whom 626 (43%) had had blood transfusion within 7 days of surgery. Both disease-free survival and patient survival were measured using a proportional hazards regression model and inverse probability of treatment weighting. We used restricted cubic splines for the association of the number of packed red blood cell units transfused with cancer recurrence and survival. We found that peri-operative blood transfusion was independently associated with survival and cancer recurrence after resection of hepatocellular carcinoma. Adjusted hazard ratios (95%CI) for the association of blood transfusion with cancer recurrence and all-cause mortality were 1.3 (1.1-1.4) and 1.9 (1.6-2.3), p < 0.001 for both. With more units transfused cancer recurrence was more likely and survival was shorter. The association of the number of transfused units was non-linear for cancer recurrence and linear response for all-cause mortality.

Fast and accurate predictions of covalent bonds in chemical space.

We assess the predictive accuracy of perturbation theory based estimates of changes in covalent bonding due to linear alchemical interpolations among molecules. We have investigated σ bonding to hydrogen, as well as σ and π bonding between main-group elements, occurring in small sets of iso-valence-electronic molecules with elements drawn from second to fourth rows in the p-block of the periodic table. Numerical evidence suggests that first order Taylor expansions of covalent bonding potentials can achieve high accuracy if (i) the alchemical interpolation is vertical (fixed geometry), (ii) it involves elements from the third and fourth rows of the periodic table, and (iii) an optimal reference geometry is used. This leads to near linear changes in the bonding potential, resulting in analytical predictions with chemical accuracy (∼1 kcal/mol). Second order estimates deteriorate the prediction. If initial and final molecules differ not only in composition but also in geometry, all estimates become substantially worse, with second order being slightly more accurate than first order. The independent particle approximation based second order perturbation theory performs poorly when compared to the coupled perturbed or finite difference approach. Taylor series expansions up to fourth order of the potential energy curve of highly symmetric systems indicate a finite radius of convergence, as illustrated for the alchemical stretching of H2 (+). Results are presented for (i) covalent bonds to hydrogen in 12 molecules with 8 valence electrons (CH4, NH3, H2O, HF, SiH4, PH3, H2S, HCl, GeH4, AsH3, H2Se, HBr); (ii) main-group single bonds in 9 molecules with 14 valence electrons (CH3F, CH3Cl, CH3Br, SiH3F, SiH3Cl, SiH3Br, GeH3F, GeH3Cl, GeH3Br); (iii) main-group double bonds in 9 molecules with 12 valence electrons (CH2O, CH2S, CH2Se, SiH2O, SiH2S, SiH2Se, GeH2O, GeH2S, GeH2Se); (iv) main-group triple bonds in 9 molecules with 10 valence electrons (HCN, HCP, HCAs, HSiN, HSiP, HSiAs, HGeN, HGeP, HGeAs); and (v) H2 (+) single bond with 1 electron.

Genetic polymorphisms in the prostaglandin pathway genes and risk of head and neck cancer.

OBJECTIVE: Previous studies examining the association between genetic variations in prostaglandin pathway and risk of head and neck cancer (HNC) have only included polymorphisms in the PTGS2 (COX2) gene. This study investigated the association between genetic polymorphisms of six prostaglandin pathway genes (PGDS, PTGDS, PTGES, PTGIS, PTGS1 and PTGS2), and risk of HNC. METHODS: Interviews regarding the consumption of alcohol, betel quid, and cigarette were conducted with 222 HNC cases and 214 controls. Genotyping was performed for 48 tag and functional single-nucleotide polymorphisms (SNPs). RESULTS: Two tag SNPs of PTGIS showed a significant association with HNC risk [rs522962: log-additive odds ratio (OR) = 1.42, 95% confidence interval (CI): 1.01-1.99 and dominant OR = 1.58, 95% CI: 1.02-2.47; rs6125671: log-additive OR = 1.49, 95% CI: 1.08-2.05 and dominant OR = 1.96, 95% CI: 1.16-3.32]. In addition, a region in PTGIS tagged by rs927068 and rs6019902 was significantly associated with risk of HNC (global P = 0.007). Finally, several SNPs interacted with betel quid and cigarette to influence the risk of HNC. CONCLUSIONS: Genetic variations in prostaglandin pathway genes are associated with risk of HNC and may modify the relationship between use of betel quid or cigarette and development of HNC.

Comparison of muscle activity between two adult groups according to the number of Shaker exercise.

The purpose of this study was to investigate the muscle activity of the suprahyoid and infrahyoid muscles according to the number of Shaker exercise. The 19 experimental subjects were recruited and randomly assigned to the two experimental groups. The 1st experimental group performed Shaker exercise once a day, and 2nd experimental group performed Shaker exercise three times a day for 6 weeks. Shaker exercise consists of isometric and isotonic contraction movement, enhancing the strength of suprahyoid muscle and increasing the opening of UES. After performing Shaker exercise for 6 weeks, the muscle activity of experimental groups was measured and analysed by surface electromyography. As a result, muscle activity of the suprahyoid and infrahyoid muscles showed significant improvement in both groups (P < 0·05). Comparing muscle activity of both groups, there was no significant difference. This means the Shaker exercise shows similar exercise effects on suprahyoid muscle which is the primary target muscle irrespective of the number of Shaker exercise. The activity of the infrahyoid muscle, which takes a supportive role, also showed significant difference between the two groups. In the results of a follow-up test after 4 weeks, muscle activity was higher than the initial status and the value of the EMG activity was statistically significant (P < 0·05). These results by EMG study may suggest that Shaker exercise performed once a day, like performing three times a day, has enough exercise effect and there is similar effect on the suprahyoid muscle between the 2 groups. In addition, the exercise effect lasts for 4 weeks after completing exercise.

Quantum mechanical treatment of variable molecular composition: from 'alchemical' changes of state functions to rational compound design.

'Alchemical' interpolation paths, i.e. coupling systems along fictitious paths without realistic correspondence, are frequently used within materials and molecular modeling simulation protocols for the estimation of changes in state functions such as free energies. We discuss alchemical changes in the context of quantum chemistry, and present illustrative numerical results for the changes of HOMO eigenvalue of the He atom due to alchemical teleportation - the simultaneous annihilation and creation of nuclear charges at different locations. To demonstrate the predictive power of alchemical first order derivatives (Hellmann-Feynman) the covalent bond potential of hydrogen fluoride and hydrogen chloride is investigated, as well as the hydrogen bond in the water-water and water-hydrogen fluoride dimer, respectively. Based on converged electron densities for one configuration, the versatility of alchemical derivatives is exemplified for the screening of entire binding potentials with reasonable accuracy. Finally, we discuss new constraints for the identification of non-linear coupling potentials for which the energy's Hellmann-Feynman derivative will yield accurate predictions.

BPR1J-097, a novel FLT3 kinase inhibitor, exerts potent inhibitory activity against AML.

BACKGROUND: Activating mutations of Fms-like tyrosine kinase 3 (FLT3) constitute a major driver in the pathogenesis of acute myeloid leukaemia (AML). Hence, pharmacological inhibitors of FLT3 are of therapeutic interest for AML. METHODS: The effects of inhibition of FLT3 activity by a novel potent FLT3 inhibitor, BPR1J-097, were investigated using in vitro and in vivo assays. RESULTS: The 50% inhibitory concentration (IC(50)) of BPR1J-097 required to inhibit FLT3 kinase activity ranged from 1 to 10 nM, and the 50% growth inhibition concentrations (GC(50)s) were 21±7 and 46±14 nM for MOLM-13 and MV4-11 cells, respectively. BPR1J-097 inhibited FLT3/signal transducer and activator of transcription 5 phosphorylation and triggered apoptosis in FLT3-driven AML cells. BPR1J-097 also showed favourable pharmacokinetic property and pronounced dose-dependent tumour growth inhibition and regression in FLT3-driven AML murine xenograft models. CONCLUSION: These results indicate that BPR1J-097 is a novel small molecule FLT-3 inhibitor with promising in vivo anti-tumour activities and suggest that BPR1J-097 may be further developed in preclinical and clinical studies as therapeutics in AML treatments.

Quantification of Rossolimo reflexes: a sensitive marker for spondylotic myelopathy.

STUDY DESIGN: Prospective study. OBJECTIVES: To assess and quantify Rossolimo reflexes using an electrophysiological test, and correlate the findings with the severity of spinal cord dysfunction in cervical and thoracic spondylotic myelopathy (CTSM). SETTING: A university neurorehabilitation center. METHODS: We enlisted 42 patients with CTSM between the fifth cervical and the ninth thoracic cord levels. Using electrophysiological assessments, Rossolimo reflexes were evaluated in all patients. Conduction latencies and amplitude of muscle action potentials (MAPs) of the reflexes were measured, analyzed and compared with the grading of spinal cord dysfunction and the cord compression ratios. RESULTS: We found a high diagnostic sensitivity of quantified Rossolimo reflex in patients with CTSM. A positive correlation exists between the MAP amplitude of Rossolimo reflexes and the different grades of spinal cord dysfunction. A negative linear relationship was found between the MAP amplitude of Rossolimo reflexes and the cord compression ratios in CTSM patients. CONCLUSION: Rossolimo reflexes can be measured by electrophysiological assessments, and we demonstrate a quantification method for an established neurological sign. Not only is the Rossolimo reflex found to be a highly sensitive test in clinical neurological examination but the electrophysiological assessment for this reflex can also serve as an objective marker for evaluation of the severity of spinal cord dysfunction in CTSM.

Successful living donor liver transplantation in portomesenteric thrombosis.

Chronic portal vein thrombosis (PVT) is often considered a relative contraindication for living donor liver transplantation due to the risks involved and higher morbidity. In this report, we describe a surgical strategy for living donor liver transplant in patient with complete PVT using venovenous bypass from the inferior mesenteric vein (IMV) and then using a jump graft from the IMV for portal inflow into the graft. IMV is a potential source for portal inflow in orthotopic liver transplant.

Item analysis for the written test of Taiwanese board certification examination in anaesthesiology using the Rasch model.

BACKGROUND: On the written test of board certification examination for anaesthesiology, the probability of a question being answered correctly is subject to two main factors, item difficulty and examinee ability. Thus, item analysis can provide insight into the appropriateness of a particular test, given the ability of examinees. METHODS: Study subjects were 36 Taiwanese examinees tested with 100 questions related to anaesthesiology. We used the Rasch model to perform item analysis of questions answered by each examinee to assess the effects of question difficulty and examinee ability using a common logit scale. Additionally, we evaluated test reliability and virtual failure rates under different criteria. RESULTS: The mean examinee ability was higher than the mean item difficulty in this written test by 1.28 (sd=0.57) logit units, which means that the examinees, on average, were able to correctly answer 78% of items. The difficulty of items decreased from 4.25 to -2.43 on the logit scale, corresponding to the probability of having a correct answer from 5% to 98%. There were 60 items with difficulty lower than the least able examinee and seven difficult items beyond the most able one. The agreement of item difficulty between test developers and our Rasch model was poor (weighted kappa=0.23). CONCLUSIONS: We demonstrated how to assess the construct validity and reliability of the written examination in order to provide useful information for future board certification examinations. The study was approved by the institutional review board with the following trial registered number: VGHIRB No. 97-08-14A.

Alchemical Normal Modes Unify Chemical Space.

In silico design of new molecules and materials with desirable quantum properties by high-throughput screening is a major challenge due to the high dimensionality of chemical space. To facilitate its navigation, we present a unification of coordinate and composition space in terms of alchemical normal modes (ANMs) which result from second order perturbation theory. ANMs assume a predominantly smooth nature of chemical space and form a basis in which new compounds can be expanded and identified. We showcase the use of ANMs for the energetics of the isoelectronic series of diatomics with 14 electrons, BN doped benzene derivatives (C6-2 x(BN) xH6 with x = 0,1,2,3), predictions for over 1.8 million BN doped coronene derivatives, and genetic energy optimizations in the entire BN-doped coronene space. Using Ge lattice scans as reference, the applicability of ANMs across the periodic table is demonstrated for III-V and IV-IV semiconductors Si, Sn, SiGe, SnGe, SiSn, as well as AlP, AlAs, AlSb, GaP, GaAs, GaSb, InP, InAs, and InSb. Analysis of our results indicates simple qualitative structure property rules for estimating energetic rankings among isomers. Useful quantitative estimates can also be obtained when few atoms are changed to neighboring or lower lying elements in the periodic table. The quality of the predictions often increases with the symmetry of system chosen as reference due to cancellation of odd order terms. Rooted in perturbation theory, the ANM approach promises to generally enable unbiased compound exploration campaigns at reduced computational cost.

Perforation predicts poor prognosis in patients with primary intestinal diffuse large B-cell lymphoma.

AIMS: To elucidate the clinicopathological features and prognostic factors of primary intestinal diffuse large B-cell lymphoma (PI-DLBL). METHODS AND RESULTS: Archival tissues from 30 tumours were used for tissue microarray construction, immunohistochemistry and interphase fluorescence in situ hybridization for chromosomal translocation. The M:F ratio was 1.7:1, with a median age of 60 years. The ileum and ileocaecum were most frequently involved (40% each). Fourteen (47%) were at stage I(E) disease, 15 (50%) at stage II(E). Five (17%) tumours were perforated at presentation. The tumours expressed Bcl-6 (73%), MUM1 (70%), Bcl-2 (67%) and CD10 (23%). Nine (30%) were classified as germinal centre B-cell (GCB) phenotype and 21 non-GCB. Eight of 30 (27%), 7/30 (23%) and 2/29 (7%) cases were positive for rearrangements involving IGH, BCL6, and C-MYC loci, respectively, whereas all cases were negative for BCL2 and CCND1 translocation. Perforation was a poor prognostic indicator, with a hazard ratio of tumour-related death at 8.75 (P = 0.001). The differentiation antigens, GCB versus non-GCB phenotype, or lymphoma-associated translocations were of no prognostic significance. CONCLUSIONS: We found a higher rate of perforation and lower frequency of GCB phenotype in PI-DLBL in Taiwan compared with other geographical areas; perforation is a poor prognostic indicator.

Role of Coronary Angiography in Pre-Liver Transplantation Cardiac Evaluation: Experience From an Asian Transplant Institution.

BACKGROUND: Liver transplant (LT) patients with significant coronary artery disease (CAD) have poorer outcomes. Pre-LT coronary angiography (CA) is associated with significant complications in cirrhotic patients. METHODS: This study aimed to identify predictors of abnormal CA in pre-LT cardiac assessment and to develop a predictive model to reduce unnecessary CA. From January 2006 to June 2013, 122 patients underwent CA based on the current institutional protocol. RESULTS: Forty-one (33.6%) patients had abnormal CA. Univariate analysis showed age ≥65 years (P = .001), cryptogenic cirrhosis (P = .046), cardiac comorbidities (P = .027), ischemic heart disease (IHD; P = .002), left ventricular hypertrophy (LVH; P = .004), hypertension (P = .002), diabetes mellitus (P = .017), dyslipidemia (P < .001), metabolic syndrome (P = .003), ≥2 CAD risk factors (P = .001), and high Framingham risk score (hard CAD risk, P = .018; cardiovascular disease: lipids, P = .002; body mass index, P < .001) to be significant predictors of abnormal CA. A predictive model was developed with the use of multivariable logistic regression and included diabetes, dyslipidemia, IHD, age ≥65 years, and LVH, achieving a specificity of 55.1% and sensitivity of 90.0%. This would reduce unnecessary CA by up to one-half in our study population (from 81 to 35) while maintaining a false negative rate of only 8.5%. CONCLUSIONS: Diabetes, dyslipidemia, IHD, age ≥65 years, and LVH appear to be predictors of abnormal CA in pre-LT patients. Our predictive model may help to better select patients for CA, although further validation is required.

Upregulation of CYP17A1 by Sp1-mediated DNA demethylation confers temozolomide resistance through DHEA-mediated protection in glioma.

Steroidogenesis-mediated production of neurosteroids is important for brain homeostasis. Cytochrome P450 17A1 (CYP17A1), which converts pregnenolone to dehydroepiandrosterone (DHEA) in endocrine organs and the brain, is required for prostate cancer progression and acquired chemotherapeutic resistance. However, whether CYP17A1-mediated DHEA synthesis is involved in brain tumor malignancy, especially in glioma, the most prevalent brain tumor, is unknown. To investigate the role of CYP17A1 in glioma, we determined that CYP17A1 expression is significantly increased in gliomas, which secrete more DHEA than normal astrocytes. We found that as gliomas became more malignant, both CYP17A1 and DHEA were significantly upregulated in temozolomide (TMZ)-resistant cells and highly invasive cells. In particular, the increase of CYP17A1 was caused by Sp1-mediated DNA demethylation, whereby Sp1 competed with DNMT3a for binding to the CYP17A1 promoter in TMZ-resistant glioma cells. CYP17A1 was required for the development of glioma cell invasiveness and resistance to TMZ-induced cytotoxicity. In addition, DHEA markedly attenuated TMZ-induced DNA damage and apoptosis. Together, our results suggest that components of the Sp1-CYP17A1-DHEA axis, which promotes the development of TMZ resistance, may serve as potential biomarkers and therapeutic targets in recurrent glioma.

Synthetic biodegradable microparticles for articular cartilage tissue engineering.

Articular cartilage tissue engineering procedures require the transplantation of chondrocytes that have been expanded in vitro. The expansion is carried out for a considerable time and can lead to a modulation of cell phenotype. However, microcarrier cultures have been shown to allow cell expansion while maintaining the phenotype. Here, we have used the biodegradable polyester poly(lactide-co-glycolide) (PLGA) in the form of microspheres and irregular shaped microparticles with a diameter between 47 and 210 microm. Surface modification of particles was carried out by ammonia plasma treatment and subsequent adsorption of collagen. Alternatively, particles were modified by partial hydrolysis and subsequent immobilization of an amine-terminated dendrimer. Each surface modification step was characterized by X-ray photoelectron spectroscopy. The effectiveness of the surface modification procedures was demonstrated by in vitro cell culture experiments using sheep articular cartilage chondrocytes. A significant influence of both the particle shape and the surface chemistry on the proliferation rate was observed while the phenotype was maintained independent of the surface chemistry or particle shape. Chondrocytes cultured on PLGA microspheres were further assessed for cartilage tissue formation in collagen type I gels in nude mice. The tissue that were formed showed the appearance of a hyaline-like cartilage and the presence of the microspheres substantially reduced the degree of collagen gel contraction over 1-2 months.

Evaluation of wound healing effect on skin-defect nude mice by using human dermis-derived mesenchymal stem cells.

We report that human dermis-derived mesenchymal stem cells (hDMSCs) possess differentiation potential of epidermis facilitating wound healing in skin-defect nude mice in combination with the treatment using gelatin/thermosensitive poly N-isopropylacrylamide (pNIPAAm)/polypropylene (PP). The results showed that the rate of cell growth and wound recovery in the hDMSC and gelatin/pNIPAAm/PP-treated group was significantly greater than those in the gelatin/pNIPAAm/PP-treated only group (P < .01). The reepithelialization marker of human pan-cytokeratin was also significantly increased on days 14 and day 21 in the wound site of hDMSCs and gelatin/pNIPAAm/PP-treated group. Furthermore, the stem cell marker of human CD13 gradually decreased during the period of wound healing. In sum, this novel method provided a transferring system for stem cell therapy, maintaining its temperature-sensitive property of easy peeling by lower temperature treatment.

The structure of an RNA "kissing" hairpin complex of the HIV TAR hairpin loop and its complement.

We have used nuclear magnetic resonance (NMR) to obtain the structure of an RNA "kissing" hairpin complex formed between the HIV-2 TAR hairpin loop and a hairpin with a complementary loop sequence. Kissing hairpins are important in natural antisense reactions; their complex is a specific target for protein binding. The complex has all six nucleotides of each loop paired to form a bent quasicontinuous helix of three coaxially stacked helices: two stems plus a loop-loop interaction helix. Experimental constraints derived from heteronuclear and homonuclear NMR data on 13C and 15N-labeled RNA led to a structure for the loop-loop helix with an average root-mean-square deviation of 0.83 (+/-0.10) A for 33 converged structures relative to the average structure. The loop-loop helix of the kissing complex is distorted compared to A-form RNA. Its major groove is blocked by the phosphodiester bonds that connect the first loop residue of each hairpin with its own stem, and it is flanked by two negatively charged phosphate clusters. The loop-loop helix has alternating helical twists between adjacent base-pairs. The base-pairs at the helix junctions are overwound and three base-pairs near the helix junctions adopt high propeller twists. All these changes reduce the distance needed for the bridging phosphodiester bonds connecting each stem and loop to cross the major groove of the loop-loop helix, and result in a deformed RNA helix with localized perturbations in the minor groove surface. The alternating helical twist pattern, plus other distortions in the loop-loop helix may be important for Rom protein recognition of the kissing hairpin complex.

Age-related retinal pigment epithelium and Bruch's membrane degeneration in senescence-accelerated mouse.

PURPOSE: To investigate age-related changes in the retinal pigment epithelium (RPE), Bruch's membrane, and choriocapillaris in the senescence-accelerated mouse (SAM). METHODS: The external and eyecup features and light and electron microscopic findings were examined in three male and two female mice of a senescence-prone mouse strain (SAM P(8)) monthly for 12 months. These results were compared with those in age-matched mice of similar background but senescence resistant (SAM R(1)). Choroidal vascular casts were prepared at 12 months in seven mice each of the SAM P(8) and SAM R(1) strains. Quantitative analysis of area of choriocapillaris was performed by automated image analysis, and the results were analyzed by paired Student's t-test. RESULTS: We found in the SAM P(8) strain that hair loss, coarseness of hair texture, and ulceration of skin appeared and increased as the age advanced (at approximately 5-9 months). Eyecup examination showed no differences. Light and electron microscopy revealed progressively more prominent abnormalities in the RPE and Bruch's membrane mice older than 10 months. Two of the five SAM P(8) mice older than 11 months showed what appeared to be intra-Bruch's membrane choroidal neovascularization. The RPE and Bruch's membrane appeared normal in the SAM R(1) strain. In the SAM P(8), vascular casts of the choriocapillaris showed a mild but significant decrease in vascular area when compared with the SAM R(1) strain at 12 months (P = 0.011). CONCLUSIONS: Senescence accelerated mice develop progressive age-related changes in the RPE-Bruch's-choriocapillaris complex that have features that may be relevant in the study of age-related macular changes in humans.

Normalization of retinal vascular permeability in experimental diabetes with genistein.

PURPOSE: To study the effects of genistein, a tyrosine kinase inhibitor, on retinal vascular permeability in an experimental diabetic rat model. METHODS: Seventy-two rats were equally divided into four groups: (1) nondiabetic control group, (2) diabetic control group, (3) diabetic rats receiving 150 mg genistein/kg food, and (4) diabetic rats receiving 300 mg genistein/kg food. Diabetes was induced by streptozotocin injection in the three diabetic groups. Rats were fed diets with or without genistein and followed for 6 months. Retinal vascular permeability was assessed by measuring radiolabeled sucrose leakage into the retina and by Western blot analysis for total retinal albumin. Retinal phosphotyrosine levels and proliferating cell nuclear antigen (PCNA) were also evaluated by Western blot analysis. RESULTS: Diabetic control rats had markedly increased retinal vascular leakage of radiolabeled sucrose compared with nondiabetic control rats. Diabetic rats receiving oral genistein had significantly less retinal vascular leakage of radiolabeled sucrose than diabetic control rats in a dose-response fashion. Diabetic control rats had increased levels of phosphotyrosine, retinal albumin, and PCNA by Western blot analysis compared with nondiabetic control rats. Rats receiving 300 mg of genistein had decreased retinal albumin by Western blot analysis. Western blot analysis demonstrated a dose-response decrease in retinal phosphotyrosine levels and PCNA in genistein-treated diabetic rats compared with diabetic control rats. CONCLUSIONS: Long-term oral administration of genistein significantly inhibits retinal vascular leakage in experimentally induced diabetic rats. Tyrosine kinase inhibition may be a useful pharmacological approach for the treatment of diabetic-induced retinal vascular leakage.

Role of follicular dendritic cells in the apoptosis of germinal center B cells.

Follicular dendritic cells (FDCs) provide the most obvious source of antigens, which are essential for the differentiation of GC B cells. It has been reported that most proliferating B cells in germinal centers undergo apoptosis. Quantitative histology shows macrophages with apoptotic debris throughout the germinal center, the highest frequency of these cells being found in the dense FDC network. Based on these findings, we hypothesized that FDC may be involved in an apoptotic pathway of the germinal center B cells. To prove this hypothesis, we performed double immunohistochemical analysis using anti-FDC mAb and peanut agglutinin (PNA), with their respective TUNEL kits. Collated data showed that a great proportion of the apoptotic cells, most of which were positive for PNA, were in close contact with FDC, which indicated an interaction between FDC and B cells in the apoptotic pathway. Further studies using double immunohistochemical staining and FACS analyses demonstrated the expression of Fas-ligand (FasL) in a subset of the FDC. These results suggest that FDC may play a role in the apoptosis of germinal center B cells via Fas-FasL interaction.

CM1, a possible novel activation molecule on human lymphocytes.

CM1 (centrocyte/-blast marker 1) defined by a mAb developed against concanavalin-A activated PBMC, is expressed specifically on some tonsillar germinal center (GC) B cells. In single flow cytometric analysis, the bone marrow did not express these molecules nor did the PBMC or the thymocytes. The peripheral B lymphocytes showed more than 90% positive, while the peripheral T lymphocytes showed approximately 60% positive at 48 h after activation by PMA/ionomycin, respectively. A western blot analysis and an immunoprecipitation for CM1 showed a band at 70 kDa. Cross-linking of CM1 with anti-CM1 mAb induced apoptosis of the GC B cells (CD38(+)IgD(-)). Immunohistochemical staining revealed that the CM1 molecule is distributed over the entire area except the proximal dark zone of the tonsillar germinal centers. These results suggest that the CM1 molecule might be involved in differentiation of the germinal center B cells as one of the novel centrocyte markers.