Empirical solvent-mediated potentials hold for both intra-molecular and inter-molecular inter-residue interactions

Whether knowledge-based intra-molecular inter-residue potentials are valid to represent inter-molecular interactions taking place at protein-protein interfaces has been questioned in several studies. Differences in the chain connectivity effect and in residue packing geometry between interfaces and single chain monomers have been pointed out as possible sources of distinct energetics for the two cases. In the present study, the interfacial regions of protein-protein complexes are examined to extract inter-molecular inter-residue potentials, using the same statistical methods as those previously adopted for intra-molecular residue pairs. Two sets of energy parameters are derived, corresponding to solvent-mediation and "average residue" mediation. The former set is shown to be highly correlated (correlation coefficient 0.89) with that previously obtained for inter-residue interactions within single chain monomers, while the latter exhibits a weaker correlation (0.69) with its intra-molecular counterpart. In addition to the close similarity of intra- and inter-molecular solvent-mediated potentials, they are shown to be significantly more residue-specific and thereby discriminative compared to the residue-mediated ones, indicating that solvent-mediation plays a major role in controlling the effective inter-residue interactions, either at interfaces, or within single monomers. Based on this observation, a reduced set of energy parameters comprising 20 one-body and 3 two-body terms is proposed (as opposed to the 20 x 20 tables of inter-residue potentials), which reproduces the conventional 20 x 20 tables with a correlation coefficient of 0.99.     

Monoclonal antibodies to mitochondrial E2 components define autoepitopes in primary biliary cirrhosis

Primary biliary cirrhosis (PBC) is an autoimmune liver disease characterized by the presence of antimitochondrial Abs (AMA). The autoantigens recognized by AMA are the E2 components of the pyruvate dehydrogenase complex (PDC-E2), the branched chain 2-oxoacid dehydrogenase complex E (BCOADC-E2), and the 2-oxoglutarate dehydrogenase complex E (OGDC-E2). Previous studies using murine monoclonal and human combinatorial Abs to PDC-E2 have demonstrated an intense linear staining pattern in the apical region of biliary epithelial cells (BEC) in PBC but not control liver. We therefore examined whether mAbs to the other mitochondrial autoantigens BCOADC-E2 and OGDC-E2 demonstrated disease-specific patterns of reactivity. Using an expressed recombinant "trihybrid" protein containing the lipoyl domains of PDC-E2, OGDC-E2, and BCOADC-E2, we immunized BALB/c mice to produce 35 mAbs specific for one or more of the above mitochondrial autoantigens. Seven of these mAbs uniquely stained the apical region of BEC in PBC. Of these seven, one was reactive to PDC-E2, two recognized BCOADC-E2, three were reactive to OGDC-E2, and one recognized all three Ags. Our current data demonstrate that, similar to our previous studies regarding PDC-E2, mAbs to BCOADC-E2 and OGDC-E2, or a molecule that cross-reacts with the inner lipoyl domain of all three enzymes, also show a uniquely intense staining pattern in the apical region of BEC in patients with PBC when compared with diseased controls. The abundance of such disease-specific determinants in the target cells of PBC raises interesting possibilities regarding the role of these autoantigens in the pathogenesis of this disease.     

Importance of a conserved TCR J alpha-encoded tyrosine for T cell recognition of an HLA B27/peptide complex

Human HLA B27-restricted cytotoxic T lymphocytes (CTL) specific for the influenza A epitope NP383-391 use similar TCR alpha and beta chains, with two closely related J alpha segments used by six of nine CTL clones from three unrelated donors (Bowness et al., Eur J. Immunol. 1993. 23: 1417-1421). The role of TCR complementarity-determining region (CDR)3alpha residues 93 and 100-102 was examined by site-directed mutagenesis, following expression of the TCR alpha and beta extracellular domains from one clone as a TCR zeta fusion heterodimer in rat basophil leukemia (RBL) cells. For the first time we have measured direct binding of tetrameric HLA B*2705/NP383-391 complexes to transfected TCR. Independently peptide-pulsed antigen-presenting cells (APC) were used to induce TCR-mediated degranulation of RBL transfectants. Our results show a key role for the conserved TCRalpha CDR3 J alpha-encoded residue Y102 in recognition of HLA B27/NP383-391. Thus the Y102D mutation abolished both tetramer binding and degranulation in the presence of peptide-pulsed APC. Even the Y102F mutation, differing only by a single hydroxyl group from the native TCR, abolished detectable degranulation. Further mutations F93A and S100R also abolished recognition. Interestingly, the N101A mutation recognized HLA B27/NP in functional assays despite having significantly reduced tetramer binding, a finding consistent with "kinetic editing" models of T cell activation. Modeling of the GRb TCR CDR3alpha loop suggests that residue Y102 contacts the HLA B*2705 alpha1 helix. It is thus possible that selection of germ-line TCRAJ-encoded residues at position 102 may be MHC driven.     

Incontinence due to an infrasphincteric ectopic ureter: why the delay in diagnosis and what the radiologist can do about it

PURPOSE: To determine (1) the reasons for the frequently long delay in the diagnosis of an infrasphincteric ectopic ureter in girls, and (2) what role the radiologist can play in decreasing the delay. MATERIALS AND METHODS: Twelve girls were referred to our hospital from June 1994 until April 1997 for evaluation of constant urinary dribbling and/or vaginal discharge. Available imaging studies, radiology reports, and clinic notes were reviewed. RESULTS: Mean age at the time of diagnosis was 6 years 7 months (range 2 years 10 months to 11 years 11 months). Mean delay until diagnosis after presentation was 2 years 5 months. Excluding the one girl whose ectopic ureter was diagnosed while she was still in diapers, mean age at the time of the first parental "complaint" was 4 years 9 months. The significance of the classic history of constant urinary dribbling was not recognized by physicians in 7 girls for 4 months to 7 years 10 months after presentation. Physical exam was not meticulously performed, as the ectopic orifice was visible in 8 of 12 girls. Imaging studies were ineffectively utilized: no imaging was done (for 2 years in 2 girls), inappropriate studies were done (ultrasound and voiding cystourethrography) and were misleading, studies were called normal when they were not (ultrasound and excretory urography), or perinatal imaging led to the incorrect assumption of a congenitally absent kidney in one girl and a multicystic dysplastic kidney in another. Excretory urography (EU) was diagnostic in all 10 girls with a duplex kidney, and computed tomography (CT) was supportive in 2 with a dysplastic kidney. CT was an adjunct in 3 girls; a Tc-99m-dimercaptosuccinic acid (DMSA) scan was needed in 2. CONCLUSION: The classic history of constant urinary dribbling in a successfully toilet-trained girl should immediately lead to an imaging search for the portion of kidney (or entire kidney) drained by an infrasphincteric ectopic ureter. EU should usually be the first imaging performed and is often the only imaging study needed.     

Plasma transforming growth factor beta1 as a predictor of radiation pneumonitis

PURPOSE: To investigate prospectively the utility of plasma transforming growth factor beta1 (TGFbeta1) as a marker for the development of symptomatic radiation pneumonitis. MATERIALS AND METHODS: Seventy-three patients with lung cancer treated with curative intent are reported herein. Plasma TGFbeta1 samples were obtained before, weekly during, and at each follow-up after radiation therapy (RT). TGFbeta1 was extracted using an acid/ethanol method. An enzyme-linked immunosorbent assay was used to quantify plasma TGFbeta1 concentrations. The TGFbeta1 level at the end of RT was considered "normal" if it was both < or = 7.5 ng/ml and less than the pretreatment value. All patients were followed for at least 6 months, unless symptomatic pneumonitis developed sooner. Pneumonitis was defined by National Cancer Institute (NCI) common toxicity criteria. RESULTS: Fifteen of the 73 patients (21%) developed symptomatic pneumonitis and the remaining 58 (79%) did not. A normal plasma TGFbeta1 by the end of RT, as defined above, was more common in patients who did not develop pneumonitis. A return of the plasma TGFbeta1 to normal accurately identified patients who would not develop pneumonitis with both a sensitivity and positive predictive value of 90%. CONCLUSION: Plasma TGFbeta1 levels appear to be a useful means to identify patients at low risk for the development of pneumonitis from thoracic RT. Thus, monitoring of plasma TGFbeta1 levels may identify candidates for dose escalation studies in the treatment of lung cancer.     

A decrement-to-familiarity interpretation of the revelation effect from forced-choice tests of recognition memory

In the revelation effect, the probability of labeling a target or a lure as "old" on item recognition tests increases if just prior to their recognition judgment, participants first identify a disguised version of the test item. The same occurs with interpolated tasks that occur just prior to a recognition judgment if the task shares constituents with the test items. One explanation of this test bias is an increased feeling of familiarity that comes from the identification stage preceding the recognition judgment (e.g., D. C. LeCompte, 1995; C. R. Lou, 1993). This study's finding in 4 experiments that 2-alternative forced-choice recognition either yields no effects of revelation or an "antirevelation" effect, even when both items were studied or nonstudied, is incongruent with this explanation. The authors argue that revelation decrements familiarity, and this results in a more liberal criterion shift. They also argue that their theory is more consistent with previous empirical data.     

The neuro-immuno-cutaneous-endocrine network: relationship of mind and skin

Skin does more than present one's "face" to the world; it plays a vital role in the maintenance of physical and mental health. As our most ancient interface, skin retains the ability to respond to both endogenous and exogenous stimuli, sensing and integrating environmental cues while transmitting intrinsic conditions to the outside world. As such, it has long been a target for the application of both medical and nonmedical therapies of healthy and diseased states. Our understanding of how the skin and topical therapies affect health is in its infancy. Conversely, we known little of how our internal systems affect our skin. By exploring an elaborate web of neuro-immuno-cutaneous-endocrine (NICE) phenomena, we seek to shed light on the generally acknowledged, but inadequately defined, relationship between mental and physical health. We use skin as our window, noting some of the biological mediators linking nervous, immune, cutaneous, and endocrine functions. It is likely that these mediators are important in homeostasis, and that they affect several dermatologic and psychiatric conditions.     

A pilot study of intracavitary hyperthermia combined with radiation in the treatment of oesophageal carcinoma

The possibility that the experiences of the "hidden" child survivors of the Holocaust (those who survived outside of the concentration camps during the Nazi occupation) had a pathological effect on their offspring was examined by comparing volunteer, matched samples of adult children of "hidden" child survivors of the Holocaust with adult children of nontraumatized U.S.-born Jewish parents on personality variables measured by the Sixteen Personality Factor Questionnaire (Cattell, Eber, & Tatsuoka, 1970). The MANOVA results indicated that there were no differences in the personality characteristics of the two groups.     

Vaccinating guinea pigs with recombinant glycoprotein D of herpes simplex virus in an efficacious adjuvant formulation elicits protection against vaginal infection

PURPOSE: This study was designed to develop improved criteria for the diagnosis of infective endocarditis and to compare these criteria with currently accepted criteria in a large series of cases. PATIENTS AND METHODS: A total of 405 consecutive cases of suspected infective endocarditis in 353 patients evaluated in a tertiary care hospital from 1985 to 1992 were analyzed using new diagnostic criteria for endocarditis. We defined two "major criteria" (typical blood culture and positive echocardiogram) and six "minor criteria" (predisposition, fever, vascular phenomena, immunologic phenomena, suggestive echocardiogram, and suggestive microbiologic findings). We also defined three diagnostic categories: (1) "definite" by pathologic or clinical criteria, (2) "possible," and (3) "rejected." Each suspected case of endocarditis was classified using both old and new criteria. Sixty-nine pathologically proven cases were reclassified after exclusion of the surgical or autopsy findings, enabling comparison of clinical diagnostic criteria in proven cases. RESULTS: Fifty-five (80%) of the 69 pathologically confirmed cases were classified as clinically definite endocarditis. The older criteria classified only 35 (51%) of the 69 pathologically confirmed cases into the analogous probable category (p < 0.0001). Twelve (17%) pathologically confirmed cases were rejected by older clinical criteria, but none were rejected by the new criteria. Seventy-one (21%) of the remaining 336 cases that were not proven pathologically were probable by older criteria, whereas the new criteria almost doubled the number of definite cases, to 135 (40%, p < 0.01). Of the 150 cases rejected by older criteria, 11 were definite, 87 were possible, and 52 were rejected by the new criteria. CONCLUSION: Application of the proposed new criteria increases the number of definite diagnoses. This should be useful for more accurate diagnosis and classification of patients with suspected endocarditis and provide better entry criteria for epidemiologic studies and clinical trials.     

Use of Monte Carlo simulation for human exposure assessment at a superfund site

This work presents a comparison of probabilistic and deterministic health risk estimates based on data from an industrial site in the northeastern United States. The risk assessment considered exposures to volatile solvents by drinking water ingestion and showering. Probability densities used as inputs included concentrations, contact rates, and exposure frequencies; dose-response inputs were single values. Deterministic risk estimates were calculated by "reasonable maximum exposure" (RME) approach recommended by the EPA Superfund program. The RME noncarcinogenic risk fell between the 90th and the 95th percentile of the probability density; the RME cancer risk fell between the 95th percentile and the maximum. These results suggest that in this case (1) EPA's deterministic RME risk was reasonably protective, (2) results of probabilistic and deterministic calculations were consistent, and (3) commercially available software Monte Carlo software effectively provided multiple risk estimates recommended by recent EPA guidance.