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Biomedical subjects

J Miller

Publications and source records attributed to J Miller.

At least 91 records · Page 5Linked to original sources
PubMed2001

Molecular mechanisms of IL-2 gene regulation following costimulation through LFA-1.

The integrin LFA-1 serves as an accessory molecule in T cell activation. In addition to its well-known role as an adhesion molecule, LFA-1 can contribute to T cell activation and up-regulation of IL-2 gene expression. However, the specific mechanisms by which LFA-1 influences T cell activation have not been elucidated. Therefore, we examined the impact of LFA-1:ICAM-1 interactions on transcriptional and posttranscriptional IL-2 gene regulation, using a costimulation-negative cell line transfected with MHC class II alone, or in combination with ICAM-1 or B7-1. IL-2 transcription was assessed utilizing transgenic mice expressing an IL-2 promoter luciferase reporter construct crossed to DO11.10 TCR-transgenic mice, and IL-2 mRNA stability was evaluated by real-time RT-PCR. Comparison of naive and previously activated T cells demonstrates a dramatic increase in IL-2-luciferase transcription in activated T cells that can, in part, be attributed to downstream signaling events. Costimulation through LFA-1 enhances transcription of the transgenic reporter construct across a wide Ag dose range, but does not affect IL-2 mRNA stability. In contrast, CD28 costimulation is clearly mediated through up-regulation of IL-2 transcription and through enhancement of mRNA stability. These results indicate that the primary pathway whereby engagement of LFA-1 through its ligand ICAM-1 up-regulates IL-2 gene expression is through enhanced IL-2 transcription, in the absence of any effect on IL-2 mRNA stabilization.

CD28 Antigens↗
PubMed2001

Donor and recipient pretransplant conditioning with nonlethal radiation and antilymphocyte serum improves the graft survival in a rat small bowel transplant model.

BACKGROUND: Lymphoid tissue within the intestinal graft require immunomodulatory strategies to prevent graft versus host disease (GVHD) after transplant. Herein, we evaluate the potential advantage of donor-specific bone marrow infusions in donor and or recipient preconditioned with total body irradiation and or antilymphocyte serum (ALS) on the incidence of GVHD and rejection after small bowel transplantation. METHODS: Heterotopic SBTx was performed from DA to Lewis rats and distributed in nine groups: control group G0 (n=4) and G1 (n=6) without irradiation; recipients in G2 (n=4) were given 400 rd although in groups 3 (n=5), G4 (n=6), G6 (n=5), G7 (n=5), and G8 (n=6) with 250 rd. Donors in G5 (n=4) and G6 were given 250 rd of total body irradiation 2 hours before intestinal retrieval. Donors and recipients in G7 and donors in G8 additionally received ALS (day -5). G1, 2, 3, 5, 6, 7, and 8 were infused with UDBM and G4 with the same amount of TCDBM. Animals received tacrolimus for 15 days and accessed for rejection, GVHD and for chimerism analysis. RESULTS: High mortality due to GVHD was observed in G2, 3, and 4, and correlated with high levels of donor T cells in recipients blood. G0 and G1 showed early acute rejection with progression toward chronic rejection, in contrast to the preconditioned groups. High and low doses of total body irradiation resulted in allogeneic and in a mixed chimerism, respectively. Decrease in donor chimeric cells after 11 weeks in preconditioned groups was correlated with severe allograft rejection. CONCLUSION: Donor preconditioning with 250 rd and or ALS combined with recipient preconditioning and donor-specific bone marrow infusions prevented GVHD and resulted in a transient mixed chimerism with inhibition of allograft rejection after small bowel transplantation.

Animals↗
PubMed2001

Infectious complications among 620 consecutive heart transplant patients at Stanford University Medical Center.

A total of 1073 infectious episodes (IEs) that occurred in 620 consecutive heart transplantation patients at Stanford Medical Center between 16 December 1980 and 30 June 1996 were reviewed. Infectious complications were a major cause of morbidity and mortality, second only to rejection as the cause of early deaths and the most common cause of late deaths. Of the IEs, 468 (43.6%) were caused by bacteria, 447 (41.7%) by viruses, 109 (10.2%) by fungi, 43 (4.0%) by Pneumocystis carinii, and 6 (0.6%) by protozoa. The largest number of IEs occurred in the lungs (301 [28.1%]). A significant reduction in the incidence of IEs and a delay in presentation after transplantation were observed; these were most likely related to the introduction of new chemoprophylactic regimens during the study period and prevention of significant disease caused by cytomegalovirus.

Adult↗
PubMed2001

Intracellular transport of MHC class II and associated invariant chain in antigen presenting cells from AP-3-deficient mocha mice.

MHC class II-restricted antigen presentation requires trafficking of newly synthesized class II-invariant chain complexes from the trans-Golgi network to endosomal, peptide-loading compartments. This transport is mediated by dileucine-like motifs within the cytosolic tail of the invariant chain. Although these signals have been well characterized, the cytosolic proteins that interact with these dileucine signals and mediate Golgi sorting and endosomal transport have not been identified. Recently, an adaptor complex, AP-3, has been identified that interacts with dileucine motifs and mediates endosomal/lysosomal transport in yeast, Drosophila, and mammals. In this report, we have assessed class II-invariant chain trafficking in a strain of mice (mocha) which lacks expression of AP-3. Our studies demonstrate that the lack of AP-3 does not affect the kinetics of invariant chain degradation, the route of class II-invariant chain transport, or the rate and extent of class II-peptide binding as assessed by the generation of SDS-stable dimers. The possible role of other known or unknown adaptor complexes in class II-invariant chain transport is discussed.

Adaptor Proteins, Vesicular Transport↗
PubMed2001

The outbreak of West Nile virus infection in the New York City area in 1999.

BACKGROUND: In late August 1999, an unusual cluster of cases of meningoencephalitis associated with muscle weakness was reported to the New York City Department of Health. The initial epidemiologic and environmental investigations suggested an arboviral cause. METHODS: Active surveillance was implemented to identify patients hospitalized with viral encephalitis and meningitis. Cerebrospinal fluid, serum, and tissue specimens from patients with suspected cases underwent serologic and viral testing for evidence of arboviral infection. RESULTS: Outbreak surveillance identified 59 patients who were hospitalized with West Nile virus infection in the New York City area during August and September of 1999. The median age of these patients was 71 years (range, 5 to 95). The overall attack rate of clinical West Nile virus infection was at least 6.5 cases per million population, and it increased sharply with age. Most of the patients (63 percent) had clinical signs of encephalitis; seven patients died (12 percent). Muscle weakness was documented in 27 percent of the patients and flaccid paralysis in 10 percent; in all of the latter, nerve conduction studies indicated an axonal polyneuropathy in 14 percent. An age of 75 years or older was an independent risk factor for death (relative risk adjusted for the presence or absence of diabetes mellitus, 8.5; 95 percent confidence interval, 1.2 to 59.1), as was the presence of diabetes mellitus (age-adjusted relative risk, 5.1; 95 percent confidence interval, 1.5 to 17.3). CONCLUSIONS: This outbreak of West Nile meningoencephalitis in the New York City metropolitan area represents the first time this virus has been detected in the Western Hemisphere. Given the subsequent rapid spread of the virus, physicians along the eastern seaboard of the United States should consider West Nile virus infection in the differential diagnosis of encephalitis and viral meningitis during the summer months, especially in older patients and in those with muscle weakness.

Adolescent↗
PubMed2001

Six-year clinical effect of donor bone marrow infusions in renal transplant patients.

BACKGROUND: To date, several single- and multicenter clinical trials have attempted to induce specific immunological unresponsiveness using donor bone marrow cell infusions to augment solid organ transplantation, but the outcomes have not been definitive. METHODS: Between September 1994 and May 1998, 63 cadaver (CAD) renal transplant recipients of either one or two postoperative donor bone marrow cell (DBMC) infusions were prospectively compared with 219 non-infused controls given equivalent immunosuppression. There was at least a 1 HLA DR antigen match present between donors and recipients. The immunosuppressive regimen included a 10-day course of OKT3 induction, and tacrolimus, mycophenolate mofetil, and methylprednisolone maintenance. A total 7.01x10(8)+/-1.9x10(8) (SD) DBMC/kg was infused into the CAD recipients on either days 4 and 11 (n=42) or one half of that dose on day 4 (n=21) postoperatively. Clinical follow-up has ranged from 2.9 to 6.3 years (mean, 4.7 years). Studies were also performed of humoral immunity and quantitative cellular chimerism. RESULTS: There is clear-cut equivalence in immunosuppressive dosaging and in the other major demographic variables in both groups. However, only 2/63 DBMC recipients had biopsy-proven chronic rejection, whereas 41/219 showed chronic rejection in the controls (P = <0.01). In both groups, mortality was not associated with rejection. The actuarial graft survival at 6.3 years in the CAD DBMC group was 84.3% compared with 72.2% in the control group (not statistically significant). However, if death with a functioning graft was excluded, graft survival was 94.1% in the DBMC group and 79.8% in the controls (P=0.039). Forty patients in the control group continue to have deteriorating renal function (increasing serum creatinine concentrations to 2 mg/dl and higher), compared with 2 patients in the DBMC group (P=0.04). In the DBMC group, chimerism in iliac crest marrow aspirates has increased 3-fold in yearly sequential measurements between 1 and 4 years postoperatively averaging 1.3+/-0.36% (SE) most recently. This has not occurred in the controls. CONCLUSIONS: There now appears to be more solid long-term evidence, in kidney transplant recipients prospectively receiving DBMC infusions, of an improvement in long-term graft survival, and of the degree of chimerism positively correlating with the absence of graft loss.

Adolescent↗
PubMed2001

Osteopenia in HIV-infected men: association with asymptomatic lactic acidemia and lower weight pre-antiretroviral therapy.

BACKGROUND: Osteopenia has been associated with antiretroviral therapy, particularly with protease inhibitors. Osteopenia in HIV-uninfected men is associated with mitochondrial defects. METHODS: Bone density was assessed by dual-energy X-ray absorptiometry (DEXA) in 221 HIV-infected men (mean age 43 years) recruited to a lipodystrophy prevalence survey. Additional parameters assessed were demographics, exercise, smoking, type(s) and duration of all antiretroviral therapy, lipodystrophy (overall and by region), CD4 counts, HIV RNA, fasting metabolic parameters (lipid, glycaemic, lactate, liver enzymes, testosterone) and regional body fat and lean mass (DEXA and L4 abdominal computed tomographic scan). RESULTS: Thirty-two patients were drug-naive; 42 were receiving nucleoside analogue reverse transcriptase inhibitors (NRTI) and 147 were receiving these plus protease inhibitors. Osteoporosis (t-score < -2.5 SD below normal) was found in seven (3%) and osteopenia (t-score -1.0 to -2.5 SD) in 44 (22%). No patient had had a fracture since being infected with HIV. The only factors independently associated on logistic regression with osteopenia or osteoporosis were higher lactate levels, even if asymptomatic [odds ratio (OR) 2.39 per 1 mmol/l increase; 95% confidence interval (CI) 1.39-4.11; P = 0.002), and lower weight prior to commencing antiretroviral therapy (OR 1.06 per 1 kg decrease; 95% CI 1.02-1.11; P = 0.006). There was no independent association with any other parameter, including type or duration of antiretroviral therapy and lipodystrophy at any site. Lower total bone mineral density was associated with lower weight prior to commencing antiretroviral therapy whereas lower spinal bone mineral density was associated mostly with higher lactate. CONCLUSION: Osteopenia in HIV-infected men is common, asymptomatic and is associated with asymptomatic NRTI-related lactic acidemia and lower weight pre-antiretroviral therapy.

Absorptiometry, Photon↗
PubMed2001

Control of a mucosal challenge and prevention of AIDS by a multiprotein DNA/MVA vaccine.

Heterologous prime/boost regimens have the potential for raising high levels of immune responses. Here we report that DNA priming followed by a recombinant modified vaccinia Ankara (rMVA) booster controlled a highly pathogenic immunodeficiency virus challenge in a rhesus macaque model. Both the DNA and rMVA components of the vaccine expressed multiple immunodeficiency virus proteins. Two DNA inoculations at 0 and 8 weeks and a single rMVA booster at 24 weeks effectively controlled an intrarectal challenge administered 7 months after the booster. These findings provide hope that a relatively simple multiprotein DNA/MVA vaccine can help to control the acquired immune deficiency syndrome epidemic.

AIDS Vaccines↗
PubMed2001

Inhibition of lysine 2,3-aminomutase by the alternative substrate 4-thialysine and characterization of the 4-thialysyl radical intermediate.

Lysine 2,3-aminomutase catalyzes the interconversion of L-lysine and L-beta-lysine. 4-Thia-L-lysine (4-thialysine) is an alternative substrate for Lysine 2,3-aminomutase. The organic free radical that appears in the steady state of the reaction of 4-thialysine is structurally analogous to the first lysine-based radical in the chemical mechanism (Wu, W., Lieder, K. W., Reed, G. H., and Frey, P. A. (1995) Biochemistry 34, 10532-10537). 4-Thialysine is a much more potent inhibitor of the reaction of lysine than would be anticipated on the basis of the value of Km for its reaction as a substrate. 4-Thialysine is here shown to be a competitive reversible inhibitor with respect to L-lysine, displaying an inhibition constant of 0.12 +/- 0.01 mM. The value of Km for 4-thialysine is 1.4 +/- 0.1 mM, and the maximum velocity Vm = 0.19 +/-0.02 micromol min(-1) mg-1 at 37 degrees C and pH 8.0. The kinetic parameters for the reaction of lysine under the same conditions are: Km = 4.2 +/- 0.5 mM and Vm = 43 +/- 1 micromol min(-1) mg(-1). The discrepancy between Km and the apparent Ki for 4-thialysine arises from the fact that the maximal velocity for 4-thialysine is only 0.44% that for L-lysine. The electron paramagnetic resonance spectra of the organic radical generated at the active site from 4-thialysine and those generated from deuterium and 3-13C-labeled forms of 4-thialysine were analyzed by simulation. Based on the resulting hyperfine splitting constants, the conformation and distribution of the unpaired spin of the radical at the active site were evaluated.

Binding, Competitive↗
PubMed2001

Genitourinary tuberculosis after renal transplantation: report of 3 cases and review.

Mycobacterium tuberculosis infection of the genitourinary tract is an uncommon disease in renal transplant recipients and presentation is atypical. Genitourinary tuberculosis is associated with graft rejection, and this diagnosis should be considered for renal transplant recipients with unexplained fever and constitutional symptoms.

Adolescent↗
PubMed2001

N-alkyl substituted analogs of the sigma receptor ligand BD1008 and traditional sigma receptor ligands affect cocaine-induced convulsions and lethality in mice.

Cocaine binds to sigma receptors with comparable affinity to its well-established interaction with dopamine transporters. Previous studies have shown BD1008 (N-[2-(3,4-dichlorophenyl)ethyl]-N-methyl-2-(1-pyrrolidinyl)ethylamine) to have high affinity and selectivity for sigma receptors, and to additionally attenuate the locomotor stimulatory effects of cocaine. Therefore, in the present study, three N-alkyl substituted analogs of BD1008 were characterized in receptor binding and behavioral studies: BD1060 (N-[2-(3,4-dichlorophenyl)ethyl]-2-(1-pyrrolidinyl)ethylamine), BD1067 (N-[2-(3,4-dichlorophenyl)ethyl]-N-ethyl-2-(1-pyrrolidinyl)ethylamine), and BD1052 (N-[2-(3,4-dichlorophenyl)ethyl]-N-allyl-2-(1-pyrrolidinyl)ethylamine). Similarly to BD1008, all three analogs exhibited high affinity and selectivity for sigma receptors. In behavioral studies, BD1008, BD1060 or BD1067 attenuated cocaine-induced convulsions and lethality in Swiss Webster mice. The protective effects appear to be mediated through sigma receptor antagonism because traditional sigma receptor antagonists with high to moderate affinity for these receptors also attenuated the behavioral toxicity of cocaine. In contrast, traditional and novel sigma receptor agonists such as di-o-tolylguanidine and BD1052 worsened the behavioral toxicity of cocaine. To further characterize the actions of the N-alkyl substituted compounds, they were microinjected into the rat red nucleus, a functional assay of sigma receptor activity, where they produced agonist vs. antagonist actions that were consistent with their effects on cocaine-induced behaviors. Together, the data demonstrate that BD1008, BD1060 or BD1067 can attenuate the behavioral toxicity of cocaine, most likely through functional antagonism of sigma receptors.

Alkylation↗
PubMed2001

Confidence and accuracy of near-threshold discrimination responses.

This article reports four subliminal perception experiments using the relationship between confidence and accuracy to assess awareness. Subjects discriminated among stimuli and indicated their confidence in each discrimination response. Subjects were classified as being aware of the stimuli if their confidence judgments predicted accuracy and as being unaware if they did not. In the first experiment, confidence predicted accuracy even at stimulus durations so brief that subjects claimed to be performing at chance. This finding indicates that subjects's claims that they are "just guessing" should not be accepted as sufficient evidence that they are completely unaware of the stimuli. Experiments 2-4 tested directly for subliminal perception by comparing the minimum exposure duration needed for better than chance discrimination performance against the minimum needed for confidence to predict accuracy. The latter durations were slightly but significantly longer, suggesting that under certain circumstances people can make perceptual discriminations even though the information that was used to make those discriminations is not consciously available.

Attitude↗
PubMed2001

Pro- and retrospective memory in late adulthood.

Everyday tasks, such as getting groceries en route from work, involve two distinct components, one prospective (i.e., remembering the plan) and the other retrospective (i.e., remembering the grocery list). The present investigation examined the size of the age-related performance declines in these components, as well as the relationship between these components and age-related differences in processing resources. The subjects were 133 community-dwelling adults between 65 and 95 years of age. They completed a large battery of tests, including tests of pro- and retrospective memory as well as tests for indexing processing resources. The results showed similar age-related declines in pro- and retrospective memory. There was only a weak relationship between pro- and retrospective memory, and the age-related decline in processing resources was related more strongly to retro- than prospective memory.

Aged↗
PubMed2001

Alteration of neuronal and endothelial nitric oxide synthase and neuropeptide Y in congenital ureteropelvic junction obstruction.

PROBLEM: We investigated whether deranged nitric oxide synthase (NOS) and neuropeptide Y (NPY) expression is detectable in the stenotic segments of patients with congenital ureteropelvic junction obstruction. METHODS: Using real-time reverse transcription-polymerase chain reaction (RT-PCR), we quantified mRNA amounts of NPY, neuronal (n), endothelial (e) and inducible (i) NOS in the stenotic segments of 20 patients with congenital ureteropelvic junction obstruction (aged 5.1+/-7.0 years) and of 21 unaffected controls (aged 23.5+/-24.2 years). Additionally, mRNAs of glyceraldehyde-3-phosphate dehydrogenase (GAPDH), smooth muscle alpha-actin (Smactin), endothelial cell marker (CD31), and protein gene product 9.5 (PGP 9.5) were evaluated. Immunohistochemistry was made for NPY, nNOS, eNOS, iNOS, PGP 9.5, and CD 31. RESULTS: The mRNA of nNOS was significantly reduced in the obstructed junctions when related to the mRNAs of Smactin (P < 0.001) or GAPDH (P < 0.05), respectively. A significant reduction was also obtained for eNOS mRNA when standardized to CD31 (P < 0.05), GAPDH or Smactin mRNA (P < 0.05, and P < 0.001, respectively). NPY, PGP 9.5 and iNOS mRNAs were found in comparable quantities in both groups. In the stenotic segments, Smactin mRNA level was about twofold higher than in our control specimens, as shown by the lower CT values for the patients in real-time PCR (16.9+/-2.0 vs 17.9+/-2.6, P < 0.05). Furthermore, Smactin, nNOS, iNOS, eNOS, and NPY mRNA levels in specimens of unaffected ureteropelvic junctions were independent of age. Major differences between control and stenotic tissues were detected by immunohistochemistry: There was a dramatic reduction of innervation density as evidenced by nNOS and NPY labeling. CONCLUSION: Taken together, we found alterations in NOS gene expression and NPY innervation in tissue specimens of patients with congenital ureteropelvic junction obstruction.

Adolescent↗
PubMed2001

Probing molecular interactions in intact antibody: antigen complexes, an electrospray time-of-flight mass spectrometry approach.

Using a combination of nanoflow-electrospray ionization and time-of-flight mass spectrometry we have analyzed the oligomeric state of the recombinant V antigen from Yersinia pestis, the causative agent of plague. The mass spectrometry results show that at pH 6.8 the V antigen in solution exists predominantly as a dimer and a weakly associated tetramer. A monoclonal antibody 7.3, raised against the V antigen, gave rise to mass spectra containing a series of well-resolved charge states at m/z 6000. After addition of aliquots of solution containing V antigen in substoichiometric and molar equivalents, the spectra revealed that two molecules of the V antigen bind to the antibody. Collision-induced dissociation of the antibody-antigen complex results in the selective release of the dimer from the complex supporting the proposed 1:2 antibody:antigen stoichiometry. Control experiments with the recombinant F1 antigen, also from Yersinia pestis, establish that the antibody is specific for the V antigen because no complex with F1 was detected even in the presence of a 10-fold molar excess of F1 antigen. More generally this work demonstrates a rapid means of assessing antigen subunit interactions as well as the stoichiometry and specificity of binding in antibody-antigen complexes.

Algorithms↗