Search for resonant second generation slepton production at the Fermilab Tevatron

We present a search for supersymmetry in the R-parity violating resonant production and decay of smuons and muon sneutrinos in the channels mu-->chi(1)(0)mu, mu-->chi(2,3,4)(0)mu, and nu(mu)-->chi(1,2)(+/-)mu. We analyzed 0.38 fb(-1) of integrated luminosity collected between April 2002 and August 2004 with the D0 detector at the Fermilab Tevatron Collider. The observed number of events is in agreement with the standard model expectation, and we calculate 95% C.L. limits on the slepton production cross section times branching fraction to gaugino plus muon, as a function of slepton and gaugino masses. In the framework of minimal supergravity, we set limits on the coupling parameter lambda(211)('), extending significantly previous results obtained in Run I of the Tevatron and at the CERN LEP collider.

Direct limits on the oscillation frequency

We report results of a study of the B(s)(0) oscillation frequency using a large sample of B(s)(0) semileptonic decays corresponding to approximately 1 fb(-1) of integrated luminosity collected by the D0 experiment at the Fermilab Tevatron Collider in 2002-2006. The amplitude method gives a lower limit on the B(s)(0) oscillation frequency at 14.8 ps(-1) at the 95% C.L. At delta m(s) = 19 ps(-1), the amplitude deviates from the hypothesis A= 0(1) by 2.5 (1.6) standard deviations, corresponding to a two-sided C.L. of 1% (10%). A likelihood scan over the oscillation frequency, delta m(s), gives a most probable value of 19 ps(-1) and a range of 17 < delta m(s) < 21 ps(-1)at the 90% C.L., assuming Gaussian uncertainties. This is the first direct two-sided bound measured by a single experiment. If delta m(s) lies above 22 ps(-1), then the probability that it would produce a likelihood minimum similar to the one observed in the interval 16-22 ps(-1) is (5.0 +/- 0.3)%.

Applications of pooled DNA samples to the assessment of population affinities: short tandem repeats

Pooled DNA samples have been used in association studies of Mendelian disease genes. This method involves combining equal quantities of DNA from patients and control subjects into separate pools and comparing the pools for distributions of genetic markers. In this study identical quantities of DNA from 300 individuals representing 6 populations were pooled and amplified for 296 loci using the touchdown polymerase chain reaction (PCR) method. The purpose of this study is to test the efficacy of pooled DNA markers in the reconstruction of the genetic structure of human populations. The populations sampled included Chuvash, Buryats, Kizhi, Native Americans, South Africans, and New York City whites. To test the accuracy of the allele-frequency distributions, we genotyped the Buryats and New York samples individually for six microsatellite markers and compared their frequencies to the allele frequencies derived from the electropherogram peak heights for the pooled DNA, producing a correlation of 0.9811 with a variance of less than 0.04. Two-dimensional scaling of genetic distances among the six populations produced clusters that reflected known historical relationships. A distance matrix was created using all 296 loci, and matrices based on individual chromosomes were correlated against the total matrix. As expected, the largest chromosomes had the highest correlations with the total matrix, whereas one of the smallest chromosomes, chromosome 22, had the lowest correlation and differed most from the combined STR distance matrix.

Search for the Higgs boson in H --> WW(*) decays in pp collisions at square root of 1.96 TeV

We present a search for the standard model Higgs boson in H --> WW(*) decays with e+e-, e+/-mu-/+, and mu+mu- final states in pp collisions at a center-of-mass energy of square root of s = 1.96 TeV. The data, collected from April 2002 to June 2004 with the D0 detector, correspond to an integrated luminosity of 300-325 pb(-1), depending on the final state. The number of events observed is consistent with the expectation from backgrounds. Limits from the combination of all three channels on the Higgs boson production cross section times branching ratio sigma x BR(H --> WW(*) are presented.

Genomic structure, organization and promoter analysis of the human F11R/F11 receptor/junctional adhesion molecule-1/JAM-A

The F11-receptor (F11R) (a.k.a. JAM-1, JAM-A, CD321) is a cell adhesion molecule of the immunoglobulin superfamily involved in platelet adhesion, secretion and aggregation. In addition, the F11R plays a critical role in the function of endothelial cells and in platelet adhesion to inflamed endothelium. In the present study, we used partial sequences of the human F11R gene, F11R cDNAs, and information in unannotated human genome databases, to delineate the F11R gene. We found that the F11R gene is composed of 13 exons (E1a, 1b, 1c, E1-E10) encoding two groups of mRNAs differing in length and sequence at their 5' UTRs, referred to as type 1 and type 2 messages. Type 1 cDNAs are shorter at the 5' end and contain a region not found within type 2 messages. Type 1 mRNAs are present in endothelial cells (EC), platelets, white blood cells and in the cell lines CMK, HeLa, K562, HOG and A549, while type 2 messages are limited to EC. Type 1 messages contain exons E1-E10 whereas type 2 messages usually contain exons E1a, 1c, part of E1 and E2-E10. The translation start site is localized in the 3' end of E1, common for both type 1 and type 2 messages. Expression of these messages is regulated by two alternative promoters, P1 and P2. P1 is a TATA-less promoter containing an initiator element, multiple transcription start sites, several GC and CCAAT boxes, and GATA, NF-kappaB and ets consensus sequences. The cloned P1 drives efficient expression of the luciferase reporter gene. A high level of similarity between human P1 and its rat and mouse counterparts was observed. Promoter P2, located upstream of P1, contains a TATA box, GC boxes, a CCAAT box and GATA and ets consensus sequences. 3' RACE provided evidence for variability in the 3' UTR due to the presence of two polyadenylation signals. The finding of multiple regulatory sites in the promoters supplements the biochemical evidence that the F11R has several different roles in the functional repertoire of endothelial cells, platelets and other cells. In particular, the presence of NF-kappaB provides additional evidence to the significance of the F11R function in the initiation of inflammatory thrombosis.

Measurement of the lifetime difference in the B0(s) system

We present a study of the decay B0(s) --> J/psiphi. We obtain the CP-odd fraction in the final state at time zero, Rperpendicular = 0.16 +/- 0.10(stat) +/- 0.02 (syst), the average lifetime of the (B0(s), B0(s)) system, tau(B0(s)) = 1.39(+0.13)(-0.16)(stat)(+0.01)(-0.02)(syst) ps, and the relative width difference between the heavy and light mass eigenstates, DeltaGamma/Gamma tripple bond (GammaL - GammaH)/Gamma = 0.24(+0.28)(-0.38)(stat)(+0.03)(-0.04)(syst). With the additional constraint from the world average of the lifetime measurements using semileptonic decays, we find tau(B0(s)) = 1.39 +/- 0.06 ps and DeltaGamma/Gamma = 0.25(+0.14)(-0.15). For the ratio of the B0(s) and B0 lifetimes we obtain tau(B0(s))/tau(B0) = 0.91 +/- 0.09(stat) +/- 0.003(syst).

Measurement of semileptonic branching fractions of B mesons to narrow D** states

Using the data accumulated in 2002-2004 with the D0 detector in proton-antiproton collisions at the Fermilab Tevatron collider with a center-of-mass energy of 1.96 TeV, the branching fractions of the decays B --> D0(1)(2420)mu+ vmuX and B --> D2(*0)(2460)mu+ vmuX and their ratio have been measured: B(b --> B) x B(B --> D0(1)mu+ vmuX) x B(D0(*0) --> D*- pi+) = [0.087 +/- 0.007(stat) +/- 0.014(syst)]%; B(b --> B) x B(B --> D2(*0) mu+ vmuX) x B(D2(*0) --> D*- pi+) = [0.035 +/- 0.007(stat) +/- 0.008(syst)]% and [B(B --> D2(*0)mu+ vmuX) x B(D2(*0) --> D*- pi+)]/[B(B --> D0(1)mu+ vmuX) x B(D0(1) --> D*- pi+)] = 0.39 +/- 0.09(stat) +/- 0.12 (syst), where the charge conjugated states are always implied.

Search for large extra spatial dimensions in dimuon production with the d0 detector

We present the results of a search for the effects of large extra spatial dimensions in pp collisions at sqrt[s] = 1.96 TeV in events containing a pair of energetic muons. The data correspond to 246 pb(-1) of integrated luminosity collected by the D0 experiment at the Fermilab Tevatron Collider. Good agreement with the expected background was found, yielding no evidence for large extra dimensions. We set 95% C.L. lower limits on the fundamental Planck scale between 0.85 and 1.27 TeV within several formalisms. These are the most stringent limits achieved in the dimuon channel to date.

An association study of 43 SNPs in 16 candidate genes with atorvastatin response

Variation in individual response to statin therapy has been widely studied for a potential genetic component. Multiple genes have been identified as potential modulators of statin response, but few study findings have replicated. To further examine these associations, 2735 individuals on statin therapy, half on atorvastatin and the other half divided among fluvastatin, lovastatin, pravastatin and simvastatin were genotyped for 43 SNPs in 16 genes that have been implicated in statin response. Associations with low-density lipoprotein cholesterol (LDL-C) lowering, total cholesterol lowering, HDL-C elevation and triglyceride lowering were examined. The only significant associations with LDL-C lowering were found with apoE2 in which carriers of the rare allele who took atorvastatin lowered their LDL-C by 3.5% more than those homozygous for the common allele and with rs2032582 (S893A in ABCB1) in which the two groups of homozygotes differed by 3% in LDL-C lowering. These genetic effects were smaller than those observed with the demographic variables of age and gender. The magnitude of all the differences found is sufficiently small that genetic data from these genes should not influence clinical decisions on statin administration.

Repeat thrombolysis for acute myocardial infarction

BACKGROUND

Thrombolysis is still the first line of treatment for acute myocardial infarction in the United Kingdom. In a significant proportion of these patients thrombolytic therapy fails to restore patency of the occluded artery or is followed by early re-infarction. The best management of this group of patients is not clear although repeat doses of thrombolysis are commonly administered especially in the district general hospitals that do not have access to invasive facilities. We performed a retrospective clinical study to determine the outcome of repeat thrombolysis for acute myocardial infarction in patients with failed initial thrombolysis or early re-infarction.

METHODS

Ninety-two patients who received two or more doses of thrombolysis for acute myocardial infarction were compared with 98 contemporary similar patients who received only one dose of thrombolysis. Case notes of all patients were examined for retrospective analysis. Main outcome measures were death, heart failure and need for in-hospital revascularization.

RESULTS

Compared to the group thrombolysed once, in the rethrombolysed group there were significantly more deaths at 30 days (p=0.0016), more heart failure (with lower mean ejection fraction), more cardiac arrests as well as more frequent coronary angiography and percutaneous coronary interventions (PCIs). The incidence of haemorrhage in the two groups did not differ.

CONCLUSIONS

The need for repeat thrombolysis identifies a group of patients with a high risk of early complications. Although repeat thrombolysis is safe, these patients then need close monitoring with a view to early intervention. For such patients admitted to district general hospitals without interventional facilities early referral to a tertiary center should be considered.

The Size and Duration of the Sumatra-Andaman Earthquake from Far-Field Static Offsets

The 26 December 2004 Sumatra earthquake produced static offsets at continuously operating GPS stations at distances of up to 4500 kilometers from the epicenter. We used these displacements to model the earthquake and include consideration of the Earth's shape and depth-varying rigidity. The results imply that the average slip was >5 meters along the full length of the rupture, including the approximately 650-kilometer-long Andaman segment. Comparison of the source derived from the far-field static offsets with seismically derived estimates suggests that 25 to 35% of the total moment release occurred at periods greater than 1 hour. Taking into consideration the strong dip dependence of moment estimates, the magnitude of the earthquake did not exceed Mw = 9.2.

Giant right coronary artery aneurysm presenting as a mediastinal mass

Coronary artery aneurysms are commonly of atherosclerotic origin and are frequently asymptomatic. However, they may have varied presentations including angina, myocardial infarction, and sudden death. A case of a giant right coronary artery aneurysm presenting with acute myocardial infarction is presented, where the aneurysm appeared to be a mediastinal mass on transthoracic and transoesophageal echocardiography. Although computed tomography and magnetic resonance imaging of the heart suggested the correct diagnosis, definitive proof came from coronary angiography. Coronary artery aneurysms should be considered in the differential diagnosis of mediastinal masses.

Immediate contact reactions to fragrance mix constituents and Myroxylon pereirae resin

We have studied patients who have positive-patch test reactions to fragrance-allergic screening substances fragrance mix (FM) or Myroxylon pereirae resin (balsam of Peru) for immediate contact reactions to the standard FM, the constituents of the FM and Myroxylon pereirae resin. In the fragrance-positive subjects (n = 60), there were positive immediate contact reactions to Myroxylon pereirae resin in 56.6% and to FM in 11.6%. In a control group (n = 50) of eczematous, patch test-negative patients there were positive immediate reactions to Myroxylon pereirae resin in 58.0% subjects and to FM in 12.0%. The absence of a significant difference between the fragrance-allergic group and control group is in keeping with a non-immunological basis for the majority of the immediate reactions seen.

Lymphomatoid contact dermatitis to para-tertyl-butyl phenol resin

Lymphomatoid contact dermatitis refers to the relatively little known phenomenon of allergic contact dermatitis producing histological features suggestive of cutaneous T-cell lymphoma. We report the first case of lymphomatoid contact dermatitis in response to para-tertyl-butyl phenol resin.

Leprosy bacillus--possibly the first chemoautotrophic human pathogen cultivated in vitro and characterised

Leprosy bacillus (LB) and leprosy derived in vitro culture forms, the chemoautotrophic nocardioform (CAN) bacteria, showed an extremely close homology and identity with each other as regards a chemoautotrophic nutritional pattern, a nocardioform morphology, a weak acid-fastness coupled with Gram and Gomori's stain positivity, an exclusive mycolate and lipid profile, a phenolic glycolipid (PGL-I) and a highly sequestrated DNA characteristic, namely, a unique small size, a low G+C % mole, an exceptionally high gamma and UV radiation resistance, and a high thermal resistance. LB/CAN bacteria (CANb) gave positive signals for 36 kDa protein PCR, as well as, for 65 kDa epitope, and hybridisation with two or more probes and also by RFLP-analysis. Both LB/and CAN bacteria exhibited bacillary multiplication in the mouse footpads (MFP), nerve infiltration and evidences for local pathogenicity associated with pronounced systemic invasion. A highly reproducible mutilation model could be established which enabled a successful application of the postulates of Koch. The proof of their total identity was their anergic reactions in LL cases counterpoised against Mitsuda type strong nodular responses, mirroring the reactions of leprosy bacilli in TT cases, in accordance with the dictum of XIth International Leprosy Congress (1978). Thus, the chemoautotrophic nutritional requirements of LB, entirely unsuspected for a medically important pathogenic bacterium, having dimorphic (both bacillary and mycelial) characters with spores, mycelia and granules and unique pathogenicity of multilation manifested through the virulence factor, the enzyme collagenase, made LB or M leprae the highly enigmatic bacterium for so long.

Bedtime H2 blockers improve nocturnal gastric acid control in GERD patients on proton pump inhibitors

AIM

Proton pump inhibitors taken twice daily before meals (proton pump inhibitor b.d. AC) effectively controls daytime gastric pH; however, nocturnal gastric acid breakthrough (NAB) occurs in more than 75% of patients. Adding an H2-blocker at bedtime decreases NAB in normal subjects. The efficacy of this regimen has not been evaluated in GERD patients. The aim of this study was to assess the effects of proton pump inhibitor b.d., both with and without bedtime H2-blocker on intragastric pH and the occurrence of NAB in GERD patients.

METHODS

Prolonged ambulatory pH studies in GERD patients were reviewed. Group A: 60 patients (mean age 53 years, male 30) taking either omeprazole 20 mg or lansoprazole 30 mg b.d. Group B: 45 patients (mean age 49 years, male 23) on proton pump inhibitor b.d. (omeprazole 20 mg or lansoprazole 30 mg) plus an H2-blocker at bedtime (ranitidine 300 mg, famotidine 40 mg or nizatidine 300 mg). Eleven patients were evaluated during treatment with both regimens (group C). The percentage time of nocturnal and daytime intragastric pH > 4 and per cent of patients with gastric NAB were analysed. In the patients with NAB, its duration and associated oesophageal acid exposure also were analysed.

RESULTS

Median percentage time intragastric pH > 4 overnight was 51% in group A, compared to 96% in group B (P < 0.0001). Median percentage daytime pH > 4 was 73% in group A and 79.8% in group B (P=0.14). Median percentage time intragastric pH >p 4 overnight increased from 54.6% without H2RA to 96.5% after adding bedtime H2RA (P=0.0013) in group C patients. NAB occurred in 82% patients in group A and 40% in group B (P < 0.0001). The mean duration of oesophageal acid exposure during NAB was significantly shorter in group B (18 +/- 6 min) than in group A (42 +/- 9 min, P=0.04).

SUMMARY

Adding a bedtime H2-blocker to the treatment enhanced nocturnal gastric pH control and decreased NAB compared to the proton pump inhibitor b.d. regimen. A bedtime H2-blocker also decreased oesophageal acid exposure during NAB.

CONCLUSION

Adding a bedtime H2-blocker to a proton pump inhibitor b.d. regimen should be considered in patients who require continued nocturnal gastric acid control whilst taking proton pump inhibitor b.d.

Epidermal growth factor (EGF)-like repeats of human tenascin-C as ligands for EGF receptor

Signaling through growth factor receptors controls such diverse cell functions as proliferation, migration, and differentiation. A critical question has been how the activation of these receptors is regulated. Most, if not all, of the known ligands for these receptors are soluble factors. However, as matrix components are highly tissue-specific and change during development and pathology, it has been suggested that select growth factor receptors might be stimulated by binding to matrix components. Herein, we describe a new class of ligand for the epidermal growth factor (EGF) receptor (EGFR) found within the EGF-like repeats of tenascin-C, an antiadhesive matrix component present during organogenesis, development, and wound repair. Select EGF-like repeats of tenascin-C elicited mitogenesis and EGFR autophosphorylation in an EGFR-dependent manner. Micromolar concentrations of EGF-like repeats induced EGFR autophosphorylation and activated extracellular signal-regulated, mitogen-activated protein kinase to levels comparable to those induced by subsaturating levels of known EGFR ligands. EGFR-dependent adhesion was noted when the ligands were tethered to inert beads, simulating the physiologically relevant presentation of tenascin-C as hexabrachion, and suggesting an increase in avidity similar to that seen for integrin ligands upon surface binding. Specific binding to EGFR was further established by immunofluorescence detection of EGF-like repeats bound to cells and cross-linking of EGFR with the repeats. Both of these interactions were abolished upon competition by EGF and enhanced by dimerization of the EGF-like repeat. Such low affinity behavior would be expected for a matrix-"tethered" ligand; i.e., a ligand which acts from the matrix, presented continuously to cell surface EGF receptors, because it can neither diffuse away nor be internalized and degraded. These data identify a new class of "insoluble" growth factor ligands and a novel mode of activation for growth factor receptors.

ATP modulates Na+ channel gating and induces a non-selective cation current in a neuronal hippocampal cell line

Extracellular ATP evoked two excitatory responses in hippocampal neuroblastoma cells (HN2). The first, an opening of a receptor-operated non-selective cation channel and the second was a leftward shift in Na+ channel activation. Both ATP (5-1000 microM) and 2',3'-(4-benzoyl)-benzoyl-ATP (Bb-ATP, 50 microM) activated a non-selective cation current reversing near 0 mV and shifted the Na+ activation and inactivation curves to the left. Based on a comparison of a series of agonists and antagonists, the inward current appeared to be partially mediated by activation of a P2X7 receptor, although hybrid channels cannot be ruled out. The shift in Na+ channel gating could be separated from the opening of the cation channel, as application of the P2Y antagonist Reactive Blue-2 and GTP shifted the Na+ current activation to the left but failed to elicit the inward cation current. Both responses to ATP and Bb-ATP were insensitive to block by the P2X antagonist suramin (300 microM) but were prevented by incubation in oxidized ATP (200 microM); a putative P2X7 receptor antagonist. Prior screening of the surface negative charge of the membrane with a high concentration of divalent cations prevented both responses. We suggest that ATP4- activates a P2X receptor and becomes trapped on a site, on or near the Na+ channel. Activation of the P2X receptor leads to the opening of a non-specific cation channel, while the binding of ATP4- leads to a modified charge sensed by the Na+ channel, similar to what occurs in the presence of charged amphiphiles as well as a number of beta-scorpion toxins.

Impact of the order of initiation of fluconazole and amphotericin B in sequential or combination therapy on killing of Candida albicans in vitro and in a rabbit model of endocarditis and pyelonephritis

In vitro time-kill studies and a rabbit model of endocarditis and pyelonephritis were used to define the impact that the order of exposure of Candida albicans to fluconazole (FLC) and amphotericin B (AMB), as sequential and combination therapies, had on the susceptibility of C. albicans to AMB and on the outcome. The contribution of FLC-induced resistance to AMB for C. albicans also was assessed. In vitro, AMB monotherapy rapidly killed each of four C. albicans strains; FLC alone was fungistatic. Preincubation of these fungi with FLC for 18 h prior to exposure to AMB decreased their susceptibilities to AMB for 8 to >40 h. Induced resistance to AMB was transient, but the duration of resistance increased with the length of FLC preincubation. Yeast sequentially incubated with FLC followed by AMB plus FLC (FLC-->AMB+FLC) showed fungistatic growth kinetics similar to that of fungi that were exposed to FLC alone. This antagonistic effect persisted for at least 24 h. Simultaneous exposure of C. albicans to AMB and FLC [AMB+FLC(simult)] demonstrated activity similar to that with AMB alone for AMB concentrations of > or =1 microg/ml; antagonism was seen using an AMB concentration of 0.5 microg/ml. The in vitro findings accurately predicted outcomes in our rabbit infection model. In vivo, AMB monotherapy and treatment with AMB for 24 h followed by AMB plus FLC (AMB-->AMB+FLC) rapidly sterilized kidneys and cardiac vegetations. AMB+FLC(simult) and FLC-->AMB treatments were slower in clearing fungi from infected tissues. FLC monotherapy and FLC-->AMB+FLC were both fungistatic and were the least active regimens. No adverse interaction was observed between AMB and FLC for the AMB-->FLC regimen. However, FLC-->AMB treatment was slower than AMB alone in clearing fungi from tissues. Thus, our in vitro and in vivo studies both demonstrate that preexposure of C. albicans to FLC reduces fungal susceptibility to AMB. The length of FLC preexposure and whether AMB is subsequently used alone or in combination with FLC determine the duration of induced resistance to AMB.

Inhibition of NF-kappaB activity enhances TRAIL mediated apoptosis in breast cancer cell lines

Most breast cancer cell lines are resistant to TNF-related apoptosis inducing ligand (TRAIL) induced apoptosis. In sensitive breast cancer cell lines TRAIL rapidly induces the cleavage and activation of caspases leading to the subsequent cleavage of downstream caspase substrates. In contrast, there is no caspase activation in the resistant cell lines. The transcription factor NF-KB can inhibit apoptosis induced by a variety of stimuli including activation of death receptors. We investigated whether NF-kappaB contributes to the resistance of breast cancer cells to TRAIL induced apoptosis. All of the resistant breast cancer cell lines expressed NF-kappaB and had detectable NF-kappaB activity in nuclear extracts prior to treatment with TRAIL. Upon TRAIL treatment, a significant increase in NF-kappaB activity was seen in most of the cell lines. To directly test if NF-kappaB activity contributes to the resistance of these cell lines to TRAIL, we transiently transfected the resistant cell lines with an inhibitor of NF-kappaB (IkappaBdeltaN) and measured TRAIL induced apoptosis in control and transfected cells. All of the resistant cell lines tested showed an increase in TRAIL induced apoptosis when transfected with the IKBdeltaN. These results demonstrate that TRAIL resistant breast cancer cells fail to rapidly activate the apoptotic machinery but they do activate NF-kappaB. Inhibition of NF-kappaB activity increases the sensitivity to TRAIL mediated apoptosis in resistant cells. These results suggest that agents which inhibit NF-kappaB should increase the clinical efficacy of TRAIL in breast cancer cells.

Polymer latexes for cell-resistant and cell-interactive surfaces

Novel polymer latexes were prepared that can be applied in several ways for the control and study of cell behavior on surfaces. Acrylic latexes with glass transitions ranging from -30 to 100 degrees C were synthesized by dispersion polymerization in a water and alcohol solution using an amphiphilic comb copolymer as a stabilizing agent. The comb had a poly(methyl methacrylate) backbone and hydrophilic poly(ethylene glycol) (PEG) side chains, which served to stabilize the dispersion and create a robust hydrophilic coating on the final latex particles. The end groups of the comb stabilizer can be selectively functionalized to obtain latex particles with a controlled density of ligands tethered to their surfaces. Latexes were prepared with adhesion peptides (RGD) linked to the surface of the acrylic beads to induce attachment and spreading of cells. Coalesced films obtained from the RGD-bearing latex particles promoted attachment of WT NR6 fibroblasts, while films from unmodified latex particles were resistant to these cells. Additionally, RGD-linked beads were embedded in cell-resistant comb polymer films to create cell-interactive surfaces with discrete clustered-ligand domains. Cell attachment and morphology were seen to vary with the surface density of the RGD-bearing latex beads.

Cloning of the human platelet F11 receptor: a cell adhesion molecule member of the immunoglobulin superfamily involved in platelet aggregation

This study demonstrates that the human platelet F11 receptor (F11R) functions as an adhesion molecule, and this finding is confirmed by the structure of the protein as revealed by molecular cloning. The F11R is a 32-/35-kd protein duplex that serves as the binding site through which a stimulatory monoclonal antibody causes platelet aggregation and granule secretion. A physiological role for the F11R protein was demonstrated by its phosphorylation after the stimulation of platelets by thrombin and collagen. A pathophysiological role for the F11R was revealed by demonstrating the presence of F11R-antibodies in patients with thrombocytopenia. Adhesion of platelets through the F11R resulted in events characteristic of the action of cell adhesion molecules (CAMs). To determine the structure of this protein, we cloned the F11R cDNA from human platelets. The predicted amino acid sequence demonstrated that it is an integral membrane protein and an immunoglobulin superfamily member containing 2 extracellular C2-type domains. The structure of the F11R as a member of a CAM family of proteins and its activity in mediating adhesion confirm each another. We conclude that the F11R is a platelet-membrane protein involved in 2 distinct processes initiated on the platelet surface. The first is antibody-induced platelet aggregation and secretion that are dependent on both the FcgammaRII and the GPIIb/IIIa integrin and that may be involved in pathophysiological processes associated with certain thrombocytopenias. The second is an F11R-mediated platelet adhesion that is not dependent on either the FcgammaRII or the fibrinogen receptor and that appears to play a role in physiological processes associated with platelet adhesion and aggregation. (Blood. 2000;95:2600-2609)

Interaction between fluconazole and amphotericin B in mice with systemic infection due to fluconazole-susceptible or -resistant strains of Candida albicans

The interaction between fluconazole (Flu) and amphotericin B (AmB) was evaluated in a murine model of systemic candidiasis for one Flu-susceptible strain (MIC, 0.5 microg/ml), two strains with intermediate Flu resistance (Flu mid-resistant strains) (MIC, 64 and 128 microg/ml), and one highly Flu-resistant strain (MIC, 512 microg/ml) of Candida albicans. Differences in fungal densities in kidneys of infected mice after 24 h of therapy and in survival rates at 62 days of mice treated with an antifungal drug or a combination of antifungal drugs for 4 days were compared. For the Flu-susceptible and Flu mid-resistant strains, the combination of Flu and AmB was antagonistic, as shown by both quantitative culture results and survival. The interaction was additive for the highly Flu-resistant strain. These results suggest that the combination of Flu and AmB should be used with caution in infections due to fungi that are usually susceptible to both antifungal agents and as empirical antifungal drug therapy.

MHC class II alpha/beta heterodimeric cell surface molecules expressed from a single proviral genome

Transplantation tolerance to renal allografts can be induced in large animal preclinical models if the donor and recipient have identical major histocompatibility complex (MHC) class II loci. Such class II matching is, however, not clinically achievable owing to the extreme diversity of class II sequences. With the ultimate goal of creating a somatic class II match in the bone marrow of an allograft recipient, the aim of the study is to develop a double-copy retrovirus construct to express both chains of the MHC class II DQ glycoprotein on a single transduced cell. Analysis of the expression patterns of the retroviral DQ transgenes in both virus producer and transduced fibroblasts revealed correct transcription and stable surface expression of the DQ heterodimers. In addition, we demonstrate that both the DQA and DQB sequences are functional within the same proviral copy, a prerequisite for efficient induction of transplantation tolerance following transduction of bone marrow precursor cells. The DQ double-copy retrovirus vector showed efficient expression of the transferred class II cDNA in murine colony-forming units for the granulocyte-monocyte lineage (CFU-GM), indicating that it is suitable for gene therapy of multimeric proteins in hematopoietic cells.

cbl-b inhibits EGF-receptor-induced apoptosis by enhancing ubiquitination and degradation of activated receptors

Studies in C. elegans and Drosophila melanogaster suggest that cbl proteins are inhibitors of epidermal growth factor receptor (EGFR) function. Here we describe that overexpression of cbl-b, a homologue of the c-cbl protooncogene, inhibits EGFR-induced apoptosis in MDA-MB-468 breast cancer cells. Overexpression of cbl-b results in a shortened duration of EGFR activation upon EGF stimulation. This is demonstrated by decreased amounts of phosphorylated EGFR as well as by inhibition of multiple downstream signaling pathways. The inhibition of signaling by cbl-b results from increased ubiquitination and degradation of the activated EGFR. The inhibitory effects of cbl-b overexpression on apoptosis and on EGFR signaling are reversed by blocking proteosomal degradation of the EGFR. These data demonstrate that the mechanism by which cbl-b inhibits EGFR-induced apoptosis is by activation-dependent degradation of the EGFR. They imply that this mechanism may be a general one whereby cbl proteins regulate intracellular signaling.

Tubby-like protein 1 homozygous splice-site mutation causes early-onset severe retinal degeneration

PURPOSE

To characterize the disease expression of an autosomal recessive human retinal degeneration associated with a mutation in TULP1 (tubby-like protein 1), a gene with currently unknown function.

METHODS

Homozygotes and heterozygotes from an extended Dominican kindred with a TULP1 splice-site gene mutation (IVS14+1,G-->A) were studied clinically and with visual function tests. Sequence analysis of TULP1 was also performed in unrelated patients with severe retinal degeneration from a North American clinic population.

RESULTS

Homozygotes had nystagmus, visual acuity of 20/200 or worse, color vision disturbances, bull's eye maculopathy, and peripheral pigmentary retinopathy. Younger patients had a relatively wide extent of kinetic visual fields; older patients had only peripheral islands. No rod function was measurable by psychophysics in any of the patients; markedly reduced cone function was detectable across the visual field of younger patients and in the remaining peripheral islands of older patients. Rod and cone electroretinograms (ERGs) were not detectable using standard methods; microvolt-level cone ERGs were present in some patients. Heterozygotes had normal visual function. No putative pathogenic sequence changes in TULP1 were observed in North American patients with comparably severe retinal phenotypes, mainly in the diagnostic category of Leber congenital amaurosis.

CONCLUSIONS

This TULP1 splice-site mutation in homozygotes causes early-onset, severe retinal degeneration involving macular and peripheral cones and rods. The constellation of phenotypic findings suggests that the TULP1 gene product is critically important for normal photoreceptor function and may play a role in retinal development.

cbl-3: a new mammalian cbl family protein

We have cloned a new human gene, cbl-3, which encodes a protein with marked homology to the cbl family of proteins. The predicted protein encoded by this gene retains the conserved phosphotyrosine binding domain (PTB) in the N-terminal and the zinc finger but is significantly shorter (MW 52.5 kDa) than the other mammalian cbl proteins. The protein lacks the extensive proline rich domain and leucine zipper seen in c-cbl and cbl-b and structurally most resembles the C. elegans and Drosophila cbl proteins. The gene is ubiquitously expressed with highest expression in the aerodigestive tract, prostate, adrenal gland, and salivary gland. The protein is phosphorylated and recruited to the EGFR upon EGF stimulation and inhibits EGF stimulated MAP kinase activation. In comparison to the other mammalian cbl proteins (e.g. cbl-b), cbl-3 interacts with a restricted range of proteins containing Src Homology 3 regions. An alternatively spliced form of the cbl-3 protein was also identified which deletes a critical region of the PTB domain and which does not interact with the EGFR nor inhibit EGF stimulated MAP kinase activation. These data demonstrate that cbl-3, a novel mammalian cbl protein, is a regulator of EGFR mediated signal transduction.

Agonist stimulation of the serotonin1A receptor causes suppression of anoxia-induced apoptosis via mitogen-activated protein kinase in neuronal HN2-5 cells

Previous studies have indicated that stimulation of neuronal inhibitory receptors, such as the serotonin1A receptor (5-HT1A-R), could cause attenuation of the activity of both N-type Ca2+ channels and N-methyl-D-aspartic acid receptors, thus resulting in protection of neurons against excitotoxicity. The purpose of this study was to investigate if the 5-HT1A-R is also coupled to an alternative pathway that culminates in suppression of apoptosis even in cells that are deficient in Ca2+ channels. Using a hippocampal neuron-derived cell line (HN2-5) that is Ca2+ channel-deficient, we demonstrate here that an alternative pathway is responsible for 5-HT1A-R-mediated protection of these cells from anoxia-triggered apoptosis, assessed by deoxynucleotidyl-transferase-mediated dUTP nick end-labeling (TUNEL). The 5-HT1A-R agonist-evoked protection was eliminated in the presence of pertussis toxin and also required phosphorylation-mediated activation of mitogen-activated protein kinase (MAPK), as evidenced by the elimination of the agonist-elicited rescue of neuronal cells by the MAPK kinase inhibitor PD98059 but not by the phosphatidylinositol 3-kinase (PI-3K) inhibitor wortmannin. Furthermore, agonist stimulation of the 5-HT1A-R caused a 60% inhibition of anoxia-stimulated caspase 3-like activity in the HN2-5 cells, and this inhibition was abrogated by PD98059 but not by wortmannin. Although agonist stimulation of the 5-HT1A-R caused an activation of PI-3Kgamma in HN2-5 cells, our results showed that this PI-3Kgamma activity was not linked to the 5-HT1A-R-promoted regulation of caspase activity and suppression of apoptosis. Thus, in the neuronal HN2-5 cells, agonist binding to the 5-HT1A-R results in MAPK-mediated inhibition of a caspase 3-like enzyme and a 60-70% suppression of anoxia-induced apoptosis through a Ca2+ channel-independent pathway.

Prevalence of hepatitis B infection in the general population: a rural community based study

BACKGROUND

Available seroprevalence studies of hepatitis B in Indian population has limitations. A community based door to door epidemiological study was conducted between December 1997 and January 1988 to look for the dynamics of hepatitis B exposure in a single village of West Bengal.

METHODS

In all, 960 inhabitants out of 1261 (according to 91 census) in a village of Birbhum district in West Bengal were interviewed and their blood were tested by ELISA for HBV exposure. Odds ratio was calculated to estimate the relative risks for each potential factor facilitating virus transmission.

RESULTS

Participation rate in the present study was 76.1%. Over all HBsAg carrier rate was found to be 5.3%. Only 2/51 (3.9%) carriers were HBeAg positive. Injection by glass syringe (odds ratio = 3.01), age < 20 years (odds ratio = 1.41) and male sex (odds ratio = 1.57) were significant risk factor.

CONCLUSION

The results of this rural, predominantly poor, agrarian worker based community data reveals a fairly large reservoir of infection (5.3%). It is mainly built-up early in life. Injection practices need to be safer in addition to HBV vaccination to fight this menace.

Externalization of phosphatidylserine may not be an early signal of apoptosis in neuronal cells, but only the phosphatidylserine-displaying apoptotic cells are phagocytosed by microglia

Earlier reports on nonneural cells have shown that the normally inner plasma membrane lipid, phosphatidylserine (PS), flip-flops out during the early stages of apoptosis, whereas DNA laddering and plasma membrane permeabilization occur during the late stages. In this study, the applicability of these parameters to CNS-derived neuronal cells was tested using hippocampal HN2-5, cells that undergo apoptosis under anoxia. Because such insults on unsynchronized cells, e.g., undifferentiated HN2-5 cells, result in both early and late apoptotic cells, we mechanically separated these cells into three fractions containing (a) cells that had completely detached during anoxia, (b) cells that remained weakly attached to the tissue culture dish and, once detached by trituration in serum-containing medium, did not reattach, and (c) cells that reattached in 2-3 h. Fractions a and b contained cells that showed pronounced DNA laddering, whereas cells in fraction c did not show any DNA laddering. Double staining with fluorescein isothiocyanate-annexin V (which binds to PS) and propidium iodide (which stains the DNA in cells with a permeable cell membrane) revealed that all cells in fraction a had a permeable cell membrane (propidium iodide-positive) and PS molecules in the outer leaflet of the plasma membrane (fluorescein isothiocyanate-annexin V-positive). By contrast, fractions b and c contained cells with no externalized PS molecules. Cells in fractions a-c also showed, respectively, 50-, 21-, and 5.5-fold higher caspase-3 (CPP32) activity than that in healthy control cells. All these results show that fraction a contained late apoptotic cells, which also had the highest CPP32 activity; cells in fraction b were at an intermediate stage, when DNA laddering had already occurred; and fraction c contained very early apoptotic cells, in which no DNA laddering had yet occurred. Therefore, in the neuronal HN2-5 cells, externalization of PS occurs only during the final stages of apoptosis when the cells have completely lost their adhesion properties. Further experiments showed that ameboid microglial cells isolated from neonatal mouse brain phagocytosed only the cells in fraction a. These results show that in CNS-derived HN2-5 cells, (a) PS externalization is a late apoptotic event and is concomitant with a complete loss of surface adhesion of the apoptotic cells and (b) PS externalization is crucial for microglial recognition and phagocytosis of the apoptotic HN2-5 cells. Thus, PS externalization could be causally linked to the final detachment of apoptotic neuronal cells, which in turn prepares them for rapid phagocytosis by microglia.

Identification of a full-length cDNA for an endogenous retrovirus of miniature swine

Endogenous retroviruses of swine are a concern in the use of pig-derived tissues for xenotransplantation into humans. The nucleotide sequence of porcine endogenous retrovirus taken from lymphocytes of miniature swine (PERV-MSL) has been characterized. PERV-MSL is a type C retrovirus of 8,132 bp with the greatest nucleic acid sequence identity to gibbon ape leukemia virus and murine leukemia virus. Constitutive production of PERV-MSL RNA has been detected in normal leukocytes and in multiple organs of swine. The copy numbers of full-length PERV sequences per genome (approximately 8 to 15) vary among swine strains. The open reading frames for gag, pol, and env in PERV-MSL have over 99% amino acid sequence identity to those of Tsukuba-1 retrovirus and are highly homologous to those of endogenous retrovirus of cell line PK15 (PK15-ERV). Most of the differences in the predicted amino acid sequences of PK15-ERV and PERV-MSL are in the SU (cell attachment) region of env. The existence of these PERV clones will enable studies of infection by endogenous retroviruses in xenotransplantation.