A survivor of breast cancer with immunity to MUC-1 mucin, and lactational mastitis

The human mucin, MUC-1, is a transmembrane glycoprotein that is produced by both normal an malignant epithelium. The MUC-1 produced by malignant epithelium is underglycosylated, which leads to the expression by tumors of novel T and B cell epitopes on the mucin polypeptide core. Similar underglycosylation occurs in the lactating breast. In this report, we describe a long-term survivor of breast cancer whose tumor strongly expressed the T- and B-cell-stimulatory epitopes. Five years after presenting with the tumor, the patient had her first pregnancy, at which time she developed fulminant lymphocytic mastitis. We demonstrate that the lactating breast produced mucin expressing the same "tumor-specific" epitopes as the original cancer. The patient had circulating anti-mucin antibodies of both the IgM and IgG isotypes (these are not found in normal controls), and mucin-specific cytotoxic T lymphocytes in the peripheral blood. Limiting-dilution analysis for mucin-specific cytotoxic T lymphocytes in three different experiments yielded frequencies of 1 in 3086, 1 in 673, and 1 in 583, compared to approximately 1 in 10(6) in normal controls. The patient remains clinically free of carcinoma after 5 additional years of follow-up. We propose that the original tumor primed the patient's immune response against the mucin epitopes, and that the re-expression of these epitopes on the lactating breast evoked a secondary immune response. It is tempting to speculate that the vigor of her anti-mucin immunity may have helped protect this patient against recurrent tumor.     

Application of input-signal design in system identification for adaptive control

An alternative approach to indirect adaptive control is considered. The proposed algorithm uses the input-signal design (probing action) in parameter estimation for the control (control action) of linear systems with unknown parameters. The probing-action input under the amplitude constraint is selected in order to achieve the parameter estimates that are most accurate with respect to the determinant ratio of the parameter covariance matrix. The control-action input is given by the cautious control law (CAUT) or alternatively by the active adaptive-control (AAC) law. The case of amplitude-constrained control input is also investigated. The parameter estimates obtained from the probing-action experiment are used to update the control-action scheme. During the control action it is still possible to update the controller parameters. For the adaptive control problem of finite horizon N = N₁ + N₂, it seems that an optimum action exists between the probing action of length N₁ and the control action of length N₂. This heuristic reasoning is illustrated by simulations. The performance of the proposed algorithm is compared with the innovation dual-control (IDC) approach.     

Comparison of standardized patients and faculty in teaching medical interviewing

PURPOSE: This randomized controlled study compared the interviewing skills of first-year medical students receiving feedback primarily from standardized patients (SPs) with those of students receiving feedback primarily from faculty. METHOD: All 154 first-year students at the University of Oklahoma College of Medicine in 1993-94 were video-taped to assess baseline and post-instruction interviewing skills. All the students, randomized to one of three study groups, attended two four-hour workshops on interviewing skills. Instruction in the groups was as similar as possible except in the matter of who provided feedback. Two rating systems were used to rate the videotaped interviews for performances of targeted skills. RESULTS: Complete, usable data were available for 120 (78%) of the students. Skill ratings using the Arizona Clinical Interview Rating Scale were significantly higher for the "types of questions used" and "use of empathy" items in the SP-led feedback group. No significant difference in ratings was detected among the groups as measured by the Rotor Interactional Analysis System. CONCLUSION: The SPs were at least as effective as the faculty in effecting behavioral changes in the first-year medical students' interviewing skills.     

Neurotoxicity resulting from coexposure to pyridostigmine bromide, deet, and permethrin: implications of Gulf War chemical exposures

Of the three-quarters of a million service personnel involved in the Persian Gulf War, approximately 30,000 have complained of neurological symptoms of unknown etiology. One contributing factor to the emergence of such symptoms may be the simultaneous exposure to multiple agents used to protect the health of service personnel, in particular, the anti-nerve agent pyridostigmine bromide (PB; 3-dimethylaminocarbonyloxy-N-methylpyridinium bromide), the insect repellent DEET (N,N-diethyl-m-toluamide), and the insecticide permethrin (3-(2,2-dichloro-ethenyl)-2,2-dimethylcyclopropanecarboxylic acid (3-phenoxyphenyl)methyl ester). This study investigated neurotoxicity produced in hens by individual or simultaneous exposure to these agents (5 d/wk for 2 months to 5 mg/kg/d PB in water, po; 500 mg/kg/d DEET, neat, sc; and 500 mg/kg/d permethrin in corn oil, sc). At these dosages, exposure to single compounds resulted in minimal toxicity. Combinations of two agents produced greater neurotoxicity than that caused by individual agents. Neurotoxicity was further enhanced following concurrent administration of all three agents. We hypothesize that competition for liver and plasma esterases by these compounds leads to their decreased breakdown and increased transport of the parent compound to nervous tissues. Thus, carbamylation of peripheral esterases by PB reduces the hydrolysis of DEET and permethrin and increases their availability to the nervous system. In effect, PB "pumps" more DEET and permethrin into the central nervous system. Consistent with this hypothesis, hens exposed to the combination of the three agents exhibited neuropathological lesions with several characteristics similar to those previously reported in studies of near-lethal doses of DEET and permethrin. If this hypothesis is correct, then blood and liver esterases play an important "buffering" role in protecting against neurotoxicity in the population at large. It also suggests that individuals with low plasma esterase activity may be predisposed to neurologic deficits produced by exposure to certain chemical mixtures.     

Bounds on "bound water": transverse nuclear magnetic resonance relaxation in barnacle muscle

Relatively mobile protons that do not exchange with D2O exist in barnacle muscle cells. These are not part of the nonfreezing "bound water" that does exchange. Ninety-seven percent of the muscle water exhibits a single transverse relaxation time of 35 milliseconds: one water molecule per thousand, which is briefly and irrotationally bound, will produce the observed relaxation properties.     

Alpha-lactalbumin possesses a distinct zinc binding site

It has been proposed that the binding of Zn2+ to alpha-lactalbumin switches the conformation to one akin to a state intermediate in the folding of the protein. However, the high resolution x-ray crystal structure of human alpha-lactalbumin-Zn2+ complex at 1.7-A resolution (pH 7.6) does not reveal any significant change in conformation from the native state. The Zn2+ ion binds specifically in the "cleft" of alpha-lactalbumin (the region which forms the active site of the homologous protein lysozyme). This may suggest a possible role for Zn2+ binding in lactose synthase complex. The coordination of the Zn2+ ion involves a symmetry-related molecule in the crystal, the crystal contacts being stabilized by a SO4(2-) ion bound at the interface between three molecules.     

Ribosomal protein L15 as a probe of 50 S ribosomal subunit structure

L15, a 15 kDa protein of the large ribosomal subunit, interacts with over ten other proteins during 50 S assembly in vitro. We have probed the interaction L15 with 23 S rRNA in 50 S ribosomal subunits by chemical footprinting, and have used localized hydroxyl radical probing, generated from Fe(II) tethered to unique sites of L15, to characterize the three-dimensional 23 S rRNA environment of L15. Footprinting of L15 was done by reconstituting purified, recombinant L15 with core particles derived from Escherichia coli 50 S subunits by treatment with 2 M LiCl. The cores migrate as compact 50 S-like particles in sucrose gradients, contain 23 S and 5 S rRNA, and lack a subset of the 50 S proteins, including L15. Using both Fe(II).EDTA and dimethyl sulfate, we have identified a strong footprint for L15 in the region spanning nucleotides 572-654 in domain II of 23 S rRNA. This footprint cannot be detected when L15 is incubated with "naked" 23 S rRNA, indicating that formation of the L15 binding site requires a partially assembled particle.Protein-tethered hydroxyl radical probing was done using mutants of L15 containing single cysteine residues at amino acid positions 68, 71 and 115. The mutant proteins were derivatized with 1-[p-(bromo-acetamido)benzyl]-EDTA. Fe(II), bound to core particles, and hydroxyl radical cleavage was initiated. Distinct but overlapping sets of cleavages were obtained in the footprinted region of domain II, and in specific regions of domains I, IV and V of 23 S rRNA. These data locate L15 in proximity to several 23 S rRNA elements that are dispersed in the secondary structure, consistent with its central role in the latter stages of 50 S subunit assembly. Furthermore, these results indicate the proximity of these rRNA regions to one another, providing constraints on the tertiary folding of 23 S rRNA.     

A novel P-selectin glycoprotein ligand-1 monoclonal antibody recognizes an epitope within the tyrosine sulfate motif of human PSGL-1 and blocks recognition of both P- and L-selectin

Interactions between P-selectin and P-selectin glycoprotein ligand-1 (PSGL-1) mediate the earliest "rolling" of leukocytes on the lumenal surface of endothelial cells at sites of inflammation. Previously, PSGL-1 has been shown to be the primary mediator of interactions between neutrophils and P-selectin, but studies on the ability of PSGL-1 to mediate interactions between P-selectin and other subsets of leukocytes have yielded variable and conflicting results. A novel IgG monoclonal antibody (MoAb) to human PSGL-1 was generated, and the specificity of this MoAb was confirmed by both flow cytometric analysis and Western blotting of cells transfected with human PSGL-1. This newly developed MoAb, KPL1, inhibited interactions between P-selectin expressing COS cells and either HL60 cells, neutrophils, or lymphocytes. Furthermore, KPL1 completely inhibited interactions between P-selectin and either purified CD4 T cells or neutrophils in a flow assay under physiological conditions, but had no effect on interactions of T cells or neutrophils with E-selectin. In addition, KPL1 blocked interactions between lymphoid cells transfected with L-selectin and COS cells expressing PSGL-1. The KPL1 epitope was mapped to a site within a consensus tyrosine sulfation motif of PSGL-1, previously shown to be essential for interaction with P-selectin and now shown to be essential for interaction with L-selectin, and to be distinct from the epitope identified by the PL1 function blocking anti-PSGL-1 MoAb. Two-color flow cytometry of normal leukocytes showed that while natural killer (NK) cells (CD16(+)), monocytes, CD4 and CD8 T cells, and alpha/beta and gamma/delta T cells were uniformly positive for PSGL-1, B cells expressed low levels of the KPL1 epitope. This low level of KPL1 staining was also observed immunohistologically in germinal centers, which had no detectable KPL1 staining, whereas T-cell areas (interfollicular region) were positive for KPL1. Interestingly, plasma cells in situ and interleukin-6-dependent myeloma cell lines were KPL1(+). Thus, PSGL-1 is expressed on essentially all blood neutrophils, NK cells, B cells, T cells, and monocytes. Variation in tyrosine sulfation during B-cell differentiation may affect the ability of B cells to interact with P- and L-selectin.     

New cyclooxygenase-2/5-lipoxygenase inhibitors. 2. 7-tert-butyl-2,3-dihydro-3,3-dimethylbenzofuran derivatives as gastrointestinal safe antiinflammatory and analgesic agents: variations of the dihydrobenzofuran ring

A series of 5-keto-substituted 7-tert-buty1-2,3-dihydro-3,3- dimethylbenzofurans (DHDMBFs) were found to be nonsteroidal antiinflammatory and analgesic agents. These compounds are inhibitors of 5-lipoxygenase (5-LOX) and cyclooxygenase (COX) with selectivity for the COX-2 isoform. A series of analogues were prepared to investigate the scope of this lead. Five ketone side chains from active DHDMBFs were used to investigate the effects of changes in the DHDMBF "core": the size and identity of the heterocycle and the substituent requirements of the heterocycle and phenyl ring. Biological testing showed that a variety of structural changes can be accommodated, but no structure was clearly superior to the DHDMBF structure.     

Screening for problem drinking: comparison of CAGE and AUDIT. Ambulatory Care Quality Improvement Project (ACQUIP). Alcohol Use Disorders Identification Test

OBJECTIVE: To compare self-administered versions of three questionnaires for detecting heavy and problem drinking: the CAGE, the Alcohol Use Disorders Identification Test (AUDIT), and an augmented version of the CAGE. DESIGN: Cross-sectional surveys. SETTING: Three Department of Veterans Affairs general medical clinics. PATIENTS: Random sample of consenting male outpatients who consumed at least 5 drinks over the past year ("drinkers"). Heavy drinkers were oversampled. MEASUREMENTS: An augmented version of the CAGE was included in a questionnaire mailed to all patients. The AUDIT was subsequently mailed to "drinkers." Comparison standards, based on the tri-level World Health Organization alcohol consumption interview and the Diagnostic Interview Schedule, included heavy drinking (> 14 drinks per week typically or > or = 5 drinks per day at least monthly) and active DSM-IIIR alcohol abuse or dependence (positive diagnosis and at least one alcohol-related symptom in the past year). Areas under receiver operating characteristic curves (AUROCs) were used to compare screening questionnaires. MAIN RESULTS: Of 393 eligible patients, 261 (66%) returned the AUDIT and completed interviews. For detection of active alcohol abuse or dependence, the CAGE augmented with three more questions (AUROC 0.871) performed better than either the CAGE alone or AUDIT (AUROCs 0.820 and 0.777, respectively). For identification of heavy-drinking patients, however, the AUDIT performed best (AUROC 0.870). To identify both heavy drinking and active alcohol abuse or dependence, the augmented CAGE and AUDIT both performed well, but the AUDIT was superior (AUROC 0.861). CONCLUSIONS: For identification of patients with heavy drinking or active alcohol abuse or dependence, the self-administered AUDIT was superior to the CAGE in this population.