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Biomedical subjects

E Epstein

Publications and source records attributed to E Epstein.

At least 37 records · Page 2Linked to original sources
PubMed2000

Characterization of auxin conjugates in Arabidopsis. Low steady-state levels of indole-3-acetyl-aspartate, indole-3-acetyl-glutamate, and indole-3-acetyl-glucose.

Amide-linked indole-3-acetic acid (IAA) conjugates constitute approximately 90% of the IAA pool in the dicot Arabidopsis, whereas ester-linked conjugates and free IAA account for approximately 10% and 1%, respectively when whole seedlings are measured. We show here that IAA-aspartate Asp, IAA-glutamate (Glu), and IAA-glucose (Glc) are present at low levels in Arabidopsis. Nine-day-old wild-type Arabidopsis seedlings yielded 17.4 +/- 4.6 ng g(-1) fresh weight IAA-Asp and 3.5 +/- 1.6 ng g(-1) fresh weight IAA-Glu, and IAA-Glc was present at 7 to 17 ng g(-1) fresh weight in 12-d-old wild-type seedlings. Total IAA content in 9-d-old Arabidopsis seedlings was 1, 200 +/- 178 ng g(-1) fresh weight, so these three IAA conjugates together made up only 3% of the conjugate pool throughout the whole plant. We detected less than wild-type levels of IAA-Asp and IAA-Glu (7.8 +/- 0.4 ng g(-1) fresh weight and 1.8 +/- 0.3 ng g(-1) fresh weight, respectively) in an Arabidopsis mutant that accumulates conjugated IAA. Our results are consistent with IAA-Asp, IAA-Glu, and IAA-Glc being either minor, transient, or specifically localized IAA metabolites under normal growth conditions and bring into question the physiological relevance of IAA-Asp accumulation in response to high concentrations of exogenous IAA.

Arabidopsis↗
PubMed2000

Dynein light chain binding to a 3'-untranslated sequence mediates parathyroid hormone mRNA association with microtubules.

The 3'-untranslated region (UTR) of mRNAs binds proteins that determine mRNA stability and localization. The 3'-UTR of parathyroid hormone (PTH) mRNA specifically binds cytoplasmic proteins. We screened an expression library for proteins that bind the PTH mRNA 3'-UTR, and the sequence of 1 clone was identical to that of the dynein light chain LC8, a component of the dynein complexes that translocate cytoplasmic components along microtubules. Recombinant LC8 binds PTH mRNA 3'-UTR, as shown by RNA electrophoretic mobility shift assay. We showed that PTH mRNA colocalizes with microtubules in the parathyroid gland, as well as with a purified microtubule preparation from calf brain, and that this association was mediated by LC8. To our knowledge, this is the first report of a dynein complex protein binding an mRNA. The dynein complex may be the motor that is responsible for transporting mRNAs to specific locations in the cytoplasm and for the consequent is asymmetric distribution of translated proteins in the cell.

3' Untranslated Regions↗
PubMed1999

Indole glucosinolate and auxin biosynthesis in Arabidopsis thaliana (L.) Heynh. glucosinolate mutants and the development of clubroot disease.

Mutants and wild type plants of Arabidopsis thaliana were analysed for differences in glucosinolate accumulation patterns, indole-3-acetic acid (IAA) biosynthesis and phenotype. A previously identified series of mutants, termed TU, with altered glucosinolate patterns was used in this study. Only the line TU8 was affected in shoot phenotype (shorter stems, altered branching pattern). Synthesis of IAA and metabolism were not much affected in the TU8 mutant during seedling development, although the content of free IAA peaked earlier in TU8 during plant development than in the wild type. Indole glucosinolates and IAA may, however, be involved in the development of clubroot disease caused by the obligate biotrophic fungus Plasmodiophora brassicae since the TU3 line had a lower infection rate than the wild type, and lines TU3 and TU8 showed decreased symptom development. The decline in clubroot formation was accompanied by a reduced number of fungal structures within the root cortex and slower development of the fungus. Indole glucosinolates were lower in infected roots of TU3 and TU8 than in control roots of these lines, whereas in wild-type plants the differences were not as prominent. Free IAA and indole-3-acetonitrile (IAN) were increased in infected roots of the wild type and mutants with normal clubroot symptoms, whereas they were reduced in infected roots of mutants TU3 and TU8. These results indicate a role for indole glucosinolates and IAN/IAA in relation to symptom development in clubroot disease.

Arabidopsis↗
PubMed1998

How often does oral treatment of toenail onychomycosis produce a disease-free nail? An analysis of published data.

OBJECTIVE: To analyze studies on oral treatment of toenail onychomycosis so as to aid clinicians and patients in making informed decisions. DATA SOURCES: Studies dealing with treatment of toenail onychomycosis were identified by means of 2 MEDLINE search strategies. One was a title search using the word "toenail"; the other search used the combined Medical Subject Headings "onychomycosis" and "therapy". STUDY SELECTION: Articles were read to ascertain that they (1) described results in toenails, (2) used both culture and microscopy, and (3) included a clinical evaluation. Not included were case reports, series of fewer than 15 subjects, reports that combined fingernail onychomycosis and toenail onychomycosis in their statistics, and articles reporting only the total number of toenails cured without providing data as to how many subjects were cured. DATA EXTRACTION: This elimination process left 26 articles, which were then analyzed by means of a checklist that included a morphologically normal nail, mycological findings, and methodological items including recurrence rate, intent-to-treat analysis, placebo group, and whether terms were defined. DATA SYNTHESIS: When there was sufficient data, the frequency with which the treatment achieved normal mycological results, a clinically normal nail, and a disease-free nail (normal-appearing nail plus normal mycological results) was calculated. Confidence intervals were calculated for disease-free nail results. CONCLUSIONS: Standard courses of terbinafine achieved a disease-free nail in approximately 35% to 50% of patients. For itraconazole, the relevant disease-free nail rate was about 25% to 40%. Disease reappearance is an important issue; unfortunately data are lacking as to its frequency.

Antifungal Agents↗
PubMed1998

Does intermittent "pulse" topical 5-fluorouracil therapy allow destruction of actinic keratoses without significant inflammation?

BACKGROUND: Topical 5-fluorouracil (5-FU) is effective in removing actinic keratoses but causes unsightly and painful erosions. Intermittent "pulse" 5-FU therapy has been described as being an effective and comfortable technique for destroying actinic keratoses. OBJECTIVE: The purpose of this study was to determine the efficacy and cutaneous side effects of intermittent 5-FU therapy. METHODS: Efficacy of treatment was evaluated by three experienced dermatologists separately comparing randomly arranged before and after photographs. Degree of skin reaction was graded from photographs taken during treatment. RESULTS: Of 13 patients treated with intermittent 5-FU, two had an excellent result, three a good result, but eight failed to show discernible improvement. Efficacy was linked to the degree of skin irritation. CONCLUSION: Pulse 5-FU failed to clear actinic keratoses in most patients. Intermittent 5-FU treatment does not dissociate its therapeutic efficacy from its undesirable erosive effects. Pulse therapy is a less intensive way of employing 5-FU and may be of value in patients unwilling to accept the erosions and discomfort that accompany the traditional course of daily 5-FU applications.

Administration, Cutaneous↗
PubMed1998

Determinant capture by MHC class II DR3 during processing of mycobacteria leprae 65kD heat shock protein by human B cells.

Using T cell immunoblotting we have characterised the immunogenic fragments derived from the Mycobacteria Leprae 65kD heat shock protein that become associated with MHC class II DR3 during processing by a human B cell line. After 5 h incubation with antigen, a peptide of approximately 12kD (approximately 110 amino acids) was the only major fragment found associated with the class II MHC. The association of this oligopeptide was abolished if an excess of a synthetic peptide representing the minimal epitope was included in the culture or when cells were incubated at 4 degrees C. This suggests that the generation of this moiety is dependent on cell metabolism and that its binding to MHC is specific. This large fragment may represent an intermediate in the processing pathway, directly demonstrating the role of MHC in determinant capture during antigen degradation.

Antigen Presentation↗
PubMed1998

Do treatment process factors mediate the relationship between type A-type B and outcome in 12-Step oriented substance abuse treatment?

AIMS: One underutilized strategy for enhancing treatment research is to examine intervening factors that link client characteristics to endpoint outcomes. This study tested the hypothesis that Type B substance abusers would demonstrate difficulties engaging in the treatment process, and that these problems would mediate their poorer outcomes. DESIGN: Longitudinal naturalistic study. SETTING: Two intensive 12-Step substance abuse treatment programs. PARTICIPANTS: A sample of 115 men and women seeking treatment. MEASUREMENT: Empirical clustering techniques were used to divide the sample, and the link between type, process factors, and 12-month outcomes was examined. FINDINGS: Hypotheses were not supported. Type Bs did not demonstrate difficulties with the treatment process, but had greater problems sustaining gains posttreatment. Contrary to prediction, Type Bs were better matched to self-help affiliation than Type As. CONCLUSIONS: Findings argue for a more optimistic perspective on treating Type Bs, and for the utility of Type A-Type B in informing treatment research.

Adult↗