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Biomedical subjects

J Miller

Publications and source records attributed to J Miller.

At least 397 records · Page 22Linked to original sources
PubMed1997

Childhood central nervous system lupus; longitudinal assessment using single photon emission computed tomography.

OBJECTIVE: Neuropsychiatric manifestations in children with systemic lupus erythematosus (SLE) occur in 30-60% of patients during the course of disease. Unlike other manifestations of childhood SLE, few laboratory studies and imaging modalities aid in the diagnosis of central nervous system (CNS) lupus. We and others have reported the usefulness of single photon emission computed tomography (SPECT) in the initial assessment of cerebral blood flow in children with active CNS involvement. We extend these observations to longterm followup using the SPECT scan to determine its usefulness in the subsequent course of CNS lupus in children. METHODS: Eleven children who developed CNS disease and fulfilled the classification criteria for SLE were included in an open pilot study. The patients were followed up to 3.5 years and presented with CNS manifestations: encephalopathy with or without grand mal seizures (N = 4), focal seizures with depression or hallucinations (N = 3), optic neuritis with transverse myelitis (N = 2), and psychosis with audiovisual hallucinations (N = 2). Initially, all children had lumbar puncture, SPECT, and serologic testing; 9 children had electroencephalogram (EEG), 7 had computerized tomography (CT), and 10 had magnetic resonance imaging (MRI). SPECT was repeated in 7 patients 1-4 months after the initial CNS event and thereafter in 10 patients annually. RESULTS: At the time of the initial CNS event, 9/11 children (82%) had normal results for lumbar puncture, 7/9 (78%) for EEG, 5/7 (71%) for CT, and 6/10 (60%) for MRI. All patients (100%) had diffusely abnormal SPECT: In addition, 5/11 (45%) tested positive for IgG antibodies to cardiolipin and dsDNA, and 4/11 (36%) had antibodies to Sm. In 5/7 children whose SPECT was repeated 1 to 4 months after the CNS event, additional perfusion defects were documented compared with initial SPECT: During the subsequent 1-3.5 years and concomitant with treatment, CNS manifestations resolved clinically, but none of the SPECT scans became normal. Perfusion defects improved over time in 4 patients and worsened in 6. CONCLUSION: SPECT scan remains a sensitive tool during initial CNS events in children with CNS lupus documenting the presence of damage during short term followup of 1-4 months. However, during longterm followup abnormalities documented by SPECT no longer correlate with the patient's clinical course, limiting the usefulness of SPECT as a clinical tool in children who recover from CNS disease.

Adolescent↗
PubMed1996

An assessment of the effects of cadaver donor bone marrow on kidney allograft recipient blood cell chimerism by a novel technique combining PCR and flow cytometry.

A new technique, the PCR-flow assay is described that has allowed for the serial identification and quantitation of discrete mononuclear cell subsets of donor (or recipient) bone marrow derived cells in cadaver kidney transplant recipients infused postoperatively with donor vertebral body bone marrow cells. With fixed permeabilized cells in flow cytometry the amplification power of the polymerase chain reaction (PCR), using fluorescent-labeled primers to identify single copy HLA class II DRbeta1 genes of either donor or recipient origin, is combined with multi-color fluorochrome-labeled CD epitope-specific monoclonal antibodies. The details of the methodology are described; these support the utility of the assay. Initial observations were made on the chimeric makeup of the peripheral blood as well as iliac crest bone marrow between six months and one year posttransplantation in recipients serially followed weekly and then monthly, concomitantly compared with a control group of stable kidney transplant recipients using similar therapeutic protocols, who did not receive cadaver bone marrow. Several findings are of note. In 14 recipients of two bone marrow infusions totalling a mean of 6.29+/-2.18x10(10) cells, donor CD34 positive (+) (immature) cells were fourteen times as numerous in peripheral blood six months postoperatively as in six recipients given half as many bone marrow cells in one infusion (averaging 3.02+/-0.5x10(10)). These donor CD34+ cells unexpectedly averaged 36+/-7% of the total (donor plus recipient) CD34+ subset counted. Moreover, iliac crest bone marrow aspirates contained an average of thirteen times this number of CD34+ cells than in the peripheral blood, supporting the notion of engraftment. Of additional interest, between six months and one year posttransplant although no donor cells could be detected in peripheral blood of the controls there was an identifiable presence of donor CD34+ cells in their iliac crest bone marrow, albeit 10-fold less than the marrow-infused patients. In the clinical follow-up, although there were three unrelated mortalities, there were no additional kidney losses with current serum creatinine concentrations averaging 1.3+/-0.06 mg/dl. In conclusion, the PCR-flow assay presents the possibility of identifying discrete subsets of donor or recipient cells that may have an immunoregulatory function.

Adoptive Transfer↗
PubMed1996

The proteolytic environment involved in MHC class II-restricted antigen presentation can be modulated by the p41 form of invariant chain.

During biosynthesis, MHC class II associates with invariant chain which exists in two forms, p31 and p41. Both forms of invariant chain prevent peptide binding to class II, facilitate transport, and enhance class II localization to Ag-processing compartments. In spite of these shared functions, presentation of some Ags can be selectively enhanced by expression of p41. Here we show that p41 can function as a protease inhibitor: 1) the functional and biochemical consequences of p41 expression can be mimicked by inhibiting cysteine proteases in vivo; 2) the amount of intracellular active cysteine proteases is dramatically decreased in p41-positive cells; and 3) a polypeptide corresponding to the p41-unique region is a potent inhibitor of cathepsin L in vitro. These data suggest that p41 can enhance Ag presentation by reducing the proteolytic activity of the Ag-processing compartment, thus protecting a subset of antigenic epitopes from excessive degradation.

Animals↗
PubMed1996

Genetic studies of the Lac repressor. XV: 4000 single amino acid substitutions and analysis of the resulting phenotypes on the basis of the protein structure.

Each amino acid from position 2 to 329 of Lac repressor was replaced by 12 or 13 of the 20 natural occurring amino acids. The resulting phenotypes are discussed on the basis of (1) the recently published structure of the Lac repressor core complexed with the inducer IPTG and (2) a model of the dimeric Lac repressor built by homology modelling from the X-ray structure of the purine repressor-corepressor-operator complex. This phenotype analysis, based on 4000 well-defined mutants, yields a functional description of each amino acid position of Lac repressor. In most cases, mutant effects can be directly correlated with the structure and function of the protein. This connection between the amino acid position and the structure and function of the protein is in most cases direct and not complicated: amino acids which are directly involved in sugar binding are affected in Lac repressor mutants of the Is type; small amino acids which can only be replaced by other small acids are located in the core of the protein; positions at which nearly all amino acids are tolerated are in most cases located on the surface of the protein. Amino acids which are highly conserved throughout the LacI family of repressors, and not directly involved in specific functions of the protein like DNA recognition or sugar binding, form a network of contacts with other amino acids. Such amino acids are either located inside one subunit, mostly at the interface between secondary structure elements, or are involved in the dimerisation interface.

Amino Acid Sequence↗
PubMed1996

Organic Electroluminescent Devices

Electroluminescence from organic materials has the potential to enable low-cost, full-color flat-panel displays, as well as other emissive products. Some materials have now demonstrated adequate efficiencies (1 to 15 lumens/watt) and lifetimes (>5000 hours) for practical use; however, the factors that govern lifetime remain poorly understood. This article provides a brief review of device principles and applications requirements and focuses on the understanding of reliability issues.

Journal Article↗
PubMed1996

Differential post-transcriptional control of ornithine decarboxylase and spermidine-spermine N1-acetyltransferase by polyamines.

Ornithine decarboxylase (ODC) and spermidine/ spermine N1-acetyltransferase (SSAT) are short-lived polyamine enzymes with rate-limiting roles in controlling polyamine biosynthesis and catabolism, respectively. We have found that treatment of MALME-3M human melanoma cells for 6 h with 10 micrograms/ml cycloheximide (CHX) increases ODC and SSAT mRNA 6-9-fold. When cells containing CHX-induced SSAT mRNA were washed and post-incubated for an additional 6 h in drug free media, enzyme activity increased only 2-fold above that in untreated cells despite the > 6-fold increase in accumulated mRNA. Inclusion of 10 microM spermine or spermidine in the post-incubation medium increased SSAT activity approximately 7-fold without further elevating SSAT mRNA levels. This indicates post-transcriptional regulation which, due to the similarity between polyamine-mediated increases in SSAT activity and available mRNA, probably occurs at the level of mRNA translation. In contrast to the SSAT response, polyamines markedly reduced ODC activity (but not mRNA) to one sixth that in cells not exposed to polyamines. The findings illustrate how via post-transcriptional mechanisms, shifts in intracellular polyamine pools can simultaneously and differentially regulate polyamine biosynthesis and catabolism. It is hypothesized that these post-transcriptional responses enable cells to rapidly and sensitively control intracellular spermidine and spermine pools.

Acetyltransferases↗
PubMed1996

Granulocyte colony-stimulating factor recruitment of CD34+ progenitors to peripheral blood: impaired mobilization in chronic granulomatous disease and adenosine deaminase--deficient severe combined immunodeficiency disease patients.

Peripheral blood (PB) CD34+ cells mobilized by granulocyte colony-stimulating factor (G-CSF) administration are potentially useful for transplantation and as a target of gene transfer for therapy of hematopoietic disorders. Efficient harvest and planning for clinical use of PB CD34+ cells ideally requires foreknowledge of the expected mobilization kinetics and yield. We developed a sensitive flow cytometric assay for accurately enumerating CD34+ cells throughout the range seen at baseline to peak mobilization. We used this assay to assess the kinetics of G-CSF-mediated mobilization of CD34+ cells to PB in normal volunteers and in patients with chronic granulomatous disease (CGD) or adenosine deaminase (ADA)-deficient severe combined immunodeficiency disease (SCID). Two dose levels of G-CSF were examined (5 and 10 micrograms/kg/d for 7 days). Both doses were well tolerated. For normal subjects and patients an increase in PB CD34+ cells was first detected only preceding the third dose of G-CSF (day 3), peaked transiently on day 5 or 6, and then decreased thereafter despite additional doses of G-CSF. With 32 normal volunteers mean peak CD34+ cell counts were 57 and 76 cells/mm2 of blood (5 and 10 micrograms doses, respectively), whereas for 18 CGD patients the mean peaks were 31 and 40 cells/mm2 of blood. For 2 ADA-deficient SCID patients studied at a G-CSF dose of 5 micrograms/kg/d, the average peak was 16 cells/mm2 of blood. For both of these patient groups mobilization of CD34+ cells to PB was impaired compared with similarly treated normal subjects (P < .05). By contrast to the kinetics of the CD34+ cell mobilization, the absolute neutrophil count (ANC) increased markedly by 6 hours after the first dose of G-CSF and then increased steadily through day 8. At days 5 and 6 (peak mobilization of CD34+ cells) the mean ANC of CGD and ADA patients was only slightly lower ( < or = 15%) than that seen with normal subjects, whereas the difference in CD34+ cell mobilization was > 48%. Thus, ANC is not a reliable surrogate to predict peak PB CD34+ cell counts and direct enumeration of PB CD34+ counts should be undertaken in decisions regarding timing and duration of apheresis to harvest a specific number of these cells. Finally, unexpected, but significant differences in the PB CD34+ cell mobilization between normal subjects and patients with inherited disorders can occur and underscores the importance of establishing the expected mobilization of PB CD34+ cells in the planning of treatment approaches using these cells.

Adenosine Deaminase↗
PubMed1996

Relapse after non-T-cell-depleted allogeneic bone marrow transplantation for chronic myelogenous leukemia: early transplantation, use of an unrelated donor, and chronic graft-versus-host disease are protective.

We analyzed the incidence of posttransplant chronic myelogenous leukemia (CML) relapse in 283 consecutive related-donor (n = 177) and unrelated-donor (n = 106) allogeneic transplant recipients. Twenty-two of 165 related-donor recipients with stable or advanced disease at the time of transplant had hematologic relapse of CML following transplant (5-year Kaplan-Meier estimate of relapse, 20%; 95% confidence interval [CI], 11 to 30%). One of 12 patients transplanted in second stable phase following blast crisis also relapsed. Fifteen related-donor transplant recipients relapsed within 5 years of transplant; however, seven relapsed between 5 and 9 years after transplant. Factors independently associated with an increased risk of posttransplant relapse for related-donor recipients included prolonged interval between diagnosis and transplant (relative risk, [RR], 3.81; P = .009) and bone marrow basophilia (RR, 5.62; P = .01). Related-donor recipients with posttransplant chronic graft-versus-host disease (CGVHD) had a decreased risk of relapse (RR, 0.24; P = .005). Only two of 106 unrelated-donor transplant recipients relapsed following transplant (5-year Kaplan-Meier estimate of relapse, 3%; 95% CI, 0% to 7%). When both related- and unrelated-donor recipients were considered, the use of an unrelated donor was independently associated with a decreased risk of relapse (RR, 0.24; P = .07). Twelve of 16 relapsing patients who received further therapy (nine of 13 who underwent second transplant and three of three who received donor leukocyte infusions) remain alive. This analysis shows that relapse, sometimes occurring long after transplant, is an important adverse outcome in allogeneic transplantation for CML. Early transplant, posttransplant CGVHD, and use of an unrelated donor are associated with a reduced incidence of relapse, perhaps due to allogeneic disparities enhancing the graft-versus-leukemia effect.

Adolescent↗
PubMed1996

Early graft loss secondary to massive hemorrhagic necrosis following orthotopic liver transplantation. Evidence for cytokine-mediated univisceral Shwartzman reaction.

Massive hemorrhagic necrosis (MHN) of the liver following orthotopic liver transplantation (OLT) occurs infrequently during an otherwise uneventful recovery 1 week after OLT. It is characterized by fever and sudden deterioration of allograft function leading to failure in the absence of vascular thrombosis. The etiology is unknown, although it is usually preceded by some degree of allograft rejection. Between 6 and 8 days after OLT, four patients (out of 150) became febrile, hypotensive, and experienced a rapid rise in transaminases within 48 hr. Two patients had evidence of mild rejection; the other two had moderate to severe acute cellular rejection. All patients were ABO identical, crossmatch negative. Bolus steroids were given followed by OKT3 in the two patients with severe rejection. Although sepsis was suspected, antibiotic therapy did not ameliorate the clinical course. Each patient progressed to MHN with severe centrilobular necrosis and variable portal infiltrate. High levels of interferon-gamma and tumor necrosis factor-alpha occurred prior to the rise in transaminases in each MHN patient (155 +/- 39 pg/ml and 414 +/- 201 pg/ml, respectively) compared with levels in OLT patients with severe rejection (14 +/- 4 pg/ml and 26 +/- 5 pg/ml, respectively, P < 0.05). These data support the concept of a cytokine-mediated inflammatory response leading to a univisceral Shwartzman reaction in the transplanted liver. Early recognition of this syndrome and retransplantation are critical for survival.

Adult↗
PubMed1996

Destructive allograft fungal arteritis following simultaneous pancreas-kidney transplantation.

Fungal arteritis of the Y graft used to revascularize the whole pancreas graft developed in 2 recipients of simultaneous pancreas-kidney transplant that were performed within 36 hr of each other. The vascular infection became manifest 6-7 days following transplantation. In both patients, the vasculitis culminated in an arterial rupture that required immediate operative intervention. This compromise of the Y grafts contributed to loss of both pancreatic grafts and necessitated vascular reconstruction to reperfuse the lower extremity. To date, both patients continue to experience normal kidney transplant function.

Adult↗
PubMed1996

Association of interleukin-10 with rejection-sparing effect in septic kidney transplant recipients.

Certain cytokines, particularly gamma-interferon (IFN) and interleukin (IL)-2 associated with TH1 cell function, have been shown to play a role in allograft rejection. One paradigm for long-term allograft acceptance involves TH2 cytokine predominance (IL-4 and IL-10). We describe two renal allograft recipients for whom immunosuppression was discontinued due to serious sepsis and who maintained stable renal function over 2-6 months without immunosuppression. During this time, there were higher levels of both IFN-gamma and IL-10 in the peripheral blood than in stable control kidney transplant recipients on immunosuppression. In one of the patients, levels of IL-10 fell, while those of IFN-gamma remained persistently elevated. This was associated with biopsy-proven rejection. Although peripheral blood cytokine levels may not reflect intragraft events, these data are consistent with an allograft protective role for IL-10 offsetting that of IFN-gamma in both patients off immunosuppression.

Adult↗
PubMed1996

A prospective study of hepatitis C virus infection in renal allograft recipients.

Hepatitis C virus (HCV) is the predominant cause of posttransplant non-A, non-B hepatitis among renal allograft recipients. Prior studies evaluating the impact of HCV in kidney transplantation have been retrospective in design and based largely on changes in serum transaminases. We studied a group of HCV-infected end-stage renal disease patients prospectively with pretransplant liver biopsies and close virologic and biochemical follow-up posttransplant. Fourteen patients have been followed a mean of 11.6 +/- 5.6 months posttransplant (range, 5-21 months). Six had changes of chronic hepatitis on pretransplant liver biopsy while 8 showed only mild histologic abnormalities. Circulating viral titers increased several-fold over baseline levels during posttransplant follow-up. Viral replication was particularly enhanced immediately following a course of antilymphocyte therapy. Although all patients showed a 2-3 fold increase in alanine aminotransferase (ALT) following transplantation, there were no association noted between pretransplant liver histology, the use of FK506 and/or cyclosporine-based immunosuppression, and the magnitude of ALT change posttransplant. The only clinical outcome found to differ significantly was a higher incidence of cytomegalovirus infection among patients with chronic hepatitis. All patients are alive with functioning grafts. There have been no episodes of fulmiinant or subfulminant liver failure. We conclude that HCV-infected patients can be safely transplanted with excellent short-term follow-up. Continued monitoring with sequential liver biopsies will be needed to define the long-term course of HCV infection in an immuno-suppressed population.

Adult↗
PubMed1996

A comprehensive genetic map of the mouse genome.

The availability of dense genetic linkage maps of mammalian genomes makes feasible a wide range of studies, including positional cloning of monogenic traits, genetic dissection of polygenic traits, construction of genome-wide physical maps, rapid marker-assisted construction of congenic strains, and evolutionary comparisons. We have been engaged for the past five years in a concerted effort to produce a dense genetic map of the laboratory mouse. Here we present the final report of this project. The map contains 7,377 genetic markers, consisting of 6,580 highly informative simple sequence length polymorphisms integrated with 797 restriction fragment length polymorphisms in mouse genes. The average spacing between markers is about 0.2 centimorgans or 400 kilobases.

Animals↗
PubMed1996

Synthesis of a lacI gene analogue with reduced CpG content.

A lacI gene analogue with reduced CpG content has been synthesized. Codon usage in the lacI gene was manipulated to remove most CpG sites (82/95; 86%) while maintaining wild-type amino acid sequence. The double-stranded gene sequence was synthesized using standard beta-cyanoethyl phosphoramidite chemistry and subsequently cloned into pBR322. Bacterial promoter sequences with different levels of activity were attached upstream of the modified coding region to study its expression in E. coli. Production of lacI protein was confirmed in a lacI- E. coli strain by Western blot analysis and by measuring repression of the lacZ gene with the chromogenic lacZ indicator, 5-bromo-4-chloro-3-indolyl-beta-D-galactopyranoside (X-gal). The modified lacI gene construct can be used as a genetic target in cultured mammalian cells or in transgenic animals to avoid high levels of background mutation associated with methylated CpG sequences. The construction scheme described here provides a general approach to remove CpG sequences from gene constructs when methylation is undesirable.

Amino Acid Sequence↗