Nontraditional post-baccalaureate students: How to better provide support for perceived mental health needs

OBJECTIVE

Mental health is noted as a central indicator of academic success. This study explored the perceived mental health needs of nontraditional post-baccalaureate students and what may increase their abilities to meet these needs.

PARTICIPANTS

Participants (n = 79) were students at a mid-sized Midwestern university enrolled in identified nontraditional programs targeting students who previously obtained a bachelor's degree and nontraditional graduate students.

METHOD

Participants completed an online survey assessing perceived mental health needs, service utilization, and potential barriers to service utilization. Surveys were analyzed using descriptive analysis, coding qualitative data, and two-tailed correlations.

RESULTS

Results demonstrated nontraditional post-baccalaureate students perceive themselves as having mental health needs due to stress and time constraints. Participants' responses reflected 5 areas that may help increase mental health service utilization.

CONCLUSIONS

Results indicate nontraditional post-baccalaureate students have perceived unmet mental health needs. Ways to help meet these needs are discussed.

Abstract P1-20-03: Withdrawn

This abstract was withdrawn by the authors.

Citation Format: Dillon SR, Evans LS, Rickel E, Lewis KE, Swanson R, Levin SD, Wolfson M, Peng SL, Swiderek KM. Withdrawn [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P1-20-03.

Binding of Collagen by Canine Blood Platelets

The binding of 125I-collagen (tropocollagen) by canine blood platelets occurred in a concentration-dependent manner but no saturation effect could be observed. The binding of collagen was not entirely specific for platelets since various eucaryotic and procaryotic cells quantitatively bound collagen as well or better.

The temporal response to added collagen appeared to be binding, 3H-serotonin release, and finally platelet aggregation. Non-polymerizing salt-soluble tropocollagen was bound as well as acid-soluble tropocollagen, however neither 3H-serotonin release nor platelet aggregation occurred. Furthermore, the binding activity was not destroyed by treatment with collagenase, galactose oxidase and glucose oxidase, nor by periodate oxidation.

Platelet aggregation closely paralleled acid soluble collagen polymerization and both events were equally inhibited by arginine; however, arginine did not interfere with collagen binding. Scanning electron microscopy revealed an unusual morphological platelet response to collagen and platelets appeared to be nucleation sites for collagen polymerization.

Abstract P1-09-10: ICOSL anti-HER2 V-mAbs: Localizing engineered ICOSL costimulatory agonists to HER2+ tumors through trastuzumab

Background: The presence of tumor infiltrating lymphocytes (TILs) has been associated with improved prognosis in HER2+ breast cancer patients. Antigen specific TCR and costimulatory receptor signaling drive increases in TIL number, effector function, and tumor cytotoxicity. Improving the number and effector phenotype of tumor localized TILs has curative potential by enhancing the adaptive and memory immune response. Targeting HER2 with the monoclonal anti-HER2 antibody trastuzumabhas improved survival in HER2+ breast cancer patients and is known to increase peripheral type I immunity, which may be reflected by increased TILs.

The Immunoglobulin Superfamily (IgSF) includes a large, diverse family of immunotherapy targets expressed on immune cells and tumors. Transmembrane IgSF receptors,CD28 and inducible T cell co-stimulator (ICOS), related costimulatory molecules expressed on T cells, interact with CD80/CD86 and ICOS ligand (ICOSL), respectively, and play critical roles in T cell activation and adaptive immunity.The Alpine Immune Science's VIgDTM platform uses directed evolution to derive novel, therapeutically-applicable IgSF extracellular domains with tailored specificity and affinity. The vIgD platform has generated human ICOSL vIgDs capable of binding both ICOS and CD28, activating both pathways. To promote anti-tumor activity of TILs in HER2+ tumors, we developed trastuzumab-ICOSL “V-mAbs” consisting of trastuzumab fused to activating ICOSL vIgDs. These V-mAbs are designed to localize to HER2+ tumors and activate antigen-specific, resident T-cells through costimulatory receptor agonism.

Methods: V-mAbs were generated by fusing ICOSL vIgDs to either the N- or C- termini of the heavy and/or light chains of trastuzumab. V-mAb binding to CD28, ICOS or HER2 was measured by flow cytometric analysis of transfected cells or ForteBio analysis. V-mAb costimulatory activity was confirmed by immobilization in the presence of anti-CD3 in a primary human T cell assay. Finally, V-mAbs were co-cultured with HER2+ target cells and human T cells; T-cell activity was measured by proliferation, cytokine production, and target lysis.

Results: V-mAbs were successfully produced and bound to CD28, ICOS and HER2. In a plate bound costimulation assay, the V-mAbs increased the amount of IFN-gamma produced by T-cells stimulated with anti-CD3. When incubated with HER2+ target cells, V-mAbs promoted T-cell proliferation, cytokine secretion, and target cell lysis. Data from in vivo studies, to determine the impact of trastuzumab V-mAbs on HER2+ cancers, will be presented when available.

Conclusions: Trastuzumab-ICOSL V-mAbs are novel ICOS- and CD28-activating immunotherapies for HER2-positive tumors, promoting T-cell proliferation, cytokine secretion, and target cell lysis in a HER2 dependent fashion. The V-mAb platform has broad potential to enable tumor-localized immune modulation via the diverse array of IgSF members. Preclinical development of trastuzumab-ICOSL clinical therapeutics is in progress.

Citation Format: Rickel E, Evans L, Swanson R, Levin SS, Rixon M, Wolfson M, Bhandari J, MacNeil S, Hoover J, Kornacker M, Capuano I, Peng SL. ICOSL anti-HER2 V-mAbs: Localizing engineered ICOSL costimulatory agonists to HER2+ tumors through trastuzumab [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P1-09-10.

Biochemical Alterations of Dermatophytes during Growth

Alterations in the biochemical constituents of mycelia were studied during the growth, development, and starvation of Microsporum quinckeanum. On the basis of dry weight, growth of this dermatophyte could be divided into four phases: lag, log, stationary, and death. The percentage of total nitrogen, inorganic phosphorus, ribonucleic acid (RNA), and protein increased rapidly during the lag phase. The percentage of protein remained constant after the initial increase; however, inorganic phosphate and RNA decreased in older mycelia. Acid-soluble materials in the cells increased in concentration as the organism aged. Chitin was present in the spores at a much higher concentration than in the mycelia. The percentage of this compound decreased rapidly until the end of the lag phase. An increase and subsequent decrease in per cent chitin occurred during the log phase. Inorganic phosphorus in the mycelia increased from the value in the spore stage to a maximum in the early log phase, and then decreased rapidly during the remainder of the growth cycle. Compounds involved in protein synthesis increased rapidly during the lag phase of growth. Changes in chemical composition of the mold during starvation indicate that carbohydrate does not form the principal endogenous reserve of M. quinckeanum, whereas lipids may represent the primary reserve material.

Quality improvement in cardiac critical care

Our quality improvement program began in 2004 to improve cardiac surgery outcomes. Early tracheal extubation in the cardiovascular intensive unit was utilized as a multidisciplinary driver for the quality improvement program. Continuous improvement in the rate of early extubation to drive multidisciplinary quality improvement in cardiac critical care correlated with decreased mortality, morbidity, and improved operational efficiency. Supportive educational efforts included, but were not limited to, principles of change, trust, competing values, crew resource management, evidence based medicine, and quality improvement.

A conserved ubiquitin ligase of the nuclear envelope/endoplasmic reticulum that functions in both ER-associated and Matalpha2 repressor degradation

Substrate discrimination in the ubiquitin-proteasome system is believed to be dictated by specific combinations of ubiquitin-protein ligases (E3s) and ubiquitin-conjugating enzymes (E2s). Here we identify Doa10/Ssm4 as a yeast E3 that is embedded in the endoplasmic reticulum (ER)/nuclear envelope yet can target the soluble transcription factor Matalpha2. Doa10 contains an unusual RING finger, which has ubiquitin-ligase activity in vitro and is essential in vivo for degradation of alpha2 via its Deg1 degradation signal. Doa10 functions with two E2s, Ubc6 and Ubc7, to ubiquitinate Deg1-bearing substrates, and it is also required for the degradation of at least one ER membrane protein. Interestingly, different short-lived ER proteins show distinct requirements for Doa10 and another ER-localized E3, Hrd1. Nevertheless, the two E3s overlap in function: A doa10Delta hrd1Delta mutant is far more sensitive to cadmium relative to either single mutant and displays strong constitutive induction of the unfolded protein response; this suggests a role for both E3s in eliminating aberrant ER proteins. The likely human ortholog of DOA10 is in the cri-du-chat syndrome critical region on chromosome 5p, suggesting that defective ubiquitin ligation might contribute to this common genetic disorder.

Resolution of Michaelis complex, acylation, and conformational change steps in the reactions of the serpin, plasminogen activator inhibitor-1, with tissue plasminogen activator and trypsin

Michaelis complex, acylation, and conformational change steps were resolved in the reactions of the serpin, plasminogen activator inhibitor-1 (PAI-1), with tissue plasminogen activator (tPA) and trypsin by comparing the reactions of active and Ser 195-inactivated enzymes with site-specific fluorescent-labeled PAI-1 derivatives that report these events. Anhydrotrypsin or S195A tPA-induced fluorescence changes in P1'-Cys and P9-Cys PAI-1 variants labeled with the fluorophore, NBD, indicative of a substrate-like interaction of the serpin reactive loop with the proteinase active-site, with the P1' label but not the P9 label perturbing the interactions by 10-60-fold. Rapid kinetic analyses of the labeled PAI-1-inactive enzyme interactions were consistent with a single-step reversible binding process involving no conformational change. Blocking of PAI-1 reactive loop-beta-sheet A interactions through mutation of the P14 Thr --> Arg or annealing a reactive center loop peptide into sheet A did not weaken the binding of the inactive enzymes, suggesting that loop-sheet interactions were unlikely to be induced by the binding. Only active trypsin and tPA induced the characteristic fluorescence changes in the labeled PAI-1 variants previously shown to report acylation and reactive loop-sheet A interactions during the PAI-1-proteinase reaction. Rapid kinetic analyses showed saturation of the reaction rate constant and, in the case of the P1'-labeled PAI-1 reaction, biphasic changes in fluorescence indicative of an intermediate resembling the noncovalent complex on the path to the covalent complex. Indistinguishable K(M) and k(lim) values of approximately 20 microM and 80-90 s(-1) for reaction of the two labeled PAI-1s with trypsin suggested that a diffusion-limited association of PAI-1 and trypsin and rate-limiting acylation step, insensitive to the effects of labeling, controlled covalent complex formation. By contrast, differing values of K(M) of 1.7 and 0.1 microM and of k(lim) of 17 and 2.6 s(-1) for tPA reactions with P1' and P9-labeled PAI-1s, respectively, suggested that tPA-PAI-1 exosite interactions, sensitive to the effects of labeling, promoted a rapid association of PAI-1 and tPA and reversible formation of an acyl-enzyme complex but impeded a rate-limiting burial of the reactive loop leading to trapping of the acyl-enzyme complex. Together, the results suggest a kinetic pathway for formation of the covalent complex between PAI-1 and proteinases involving the initial formation of a Michaelis-type noncovalent complex without significant conformational change, followed by reversible acylation and irreversible reactive loop conformational change steps that trap the proteinase in a covalent complex.

The pH dependence of serpin-proteinase complex dissociation reveals a mechanism of complex stabilization involving inactive and active conformational states of the proteinase which are perturbable by calcium

Serpin family protein proteinase inhibitors trap proteinases at the acyl-intermediate stage of cleavage of the serpin as a proteinase substrate by undergoing a dramatic conformational change, which is thought to distort the proteinase active site and slow deacylation. To investigate the extent to which proteinase catalytic function is defective in the serpin-proteinase complex, we compared the pH dependence of dissociation of several serpin-proteinase acyl-complexes with that of normal guanidinobenzoyl-proteinase acyl-intermediate complexes. Whereas the apparent rate constant for dissociation of guanidinobenzoyl-proteinase complexes (k(diss, app)) showed a pH dependence characteristic of His-57 catalysis of complex deacylation, the pH dependence of k(diss, app) for the serpin-proteinase complexes showed no evidence for His-57 involvement in complex deacylation and was instead characteristic of a hydroxide-mediated deacylation similar to that observed for the hydrolysis of tosylarginine methyl ester. Hydroxylamine enhanced the rate of serpin-proteinase complex dissociation but with a rate constant for nucleophilic attack on the acyl bond several orders of magnitude slower than that of hydroxide, implying limited accessibility of the acyl bond in the complex. The addition of 10-100 mm Ca(2+) ions stimulated up to 80-fold the dissociation rate constant of several serpin-trypsin complexes in a saturable manner at neutral pH and altered the pH dependence to a pattern characteristic of His-57-catalyzed complex deacylation. These results support a mechanism of kinetic stabilization of serpin-proteinase complexes wherein the complex is trapped as an acyl-intermediate by a serpin conformational change-induced inactivation of the proteinase catalytic function, but suggest that the inactive proteinase conformation in the complex is in equilibrium with an active proteinase conformation that can be stabilized by the preferential binding of an allosteric ligand such as Ca(2+).

The antithrombin P1 residue is important for target proteinase specificity but not for heparin activation of the serpin. Characterization of P1 antithrombin variants with altered proteinase specificity but normal heparin activation

Heparin has been proposed to conformationally activate the serpin, antithrombin, by making the reactive center loop P1 arginine residue accessible to proteinases. To evaluate this proposal, we determined the effect of mutating the P1 arginine on antithrombin's specificity for target and nontarget proteinases in both native and heparin-activated states of the serpin. As expected, mutation of the P1 arginine to tryptophan, histidine, leucine, and methionine converted the specificity of antithrombin from a trypsin inhibitor (k(assoc) = 2 x 10(5) M(-1) s(-1)) to a chymotrypsin inhibitor (k(assoc) = 10(3)-10(5) M(-1) s(-1)). However, heparin pentasaccharide activation increased the reactivity of the P1 variants with chymotrypsin or of the wild-type inhibitor with trypsin only 2-6-fold, implying that the P1 residue had similar accessibilities to these proteinases in native and activated states. Mutation of the P1 arginine greatly reduced k(assoc) for antithrombin inhibition of thrombin and factor Xa from 40- to 5000-fold, but heparin normally accelerated the reactions of the variant antithrombins with these enzymes to make them reasonably efficient inhibitors (k(assoc) = 10(3)-10(4) M(-1) s(-1)). Fluorescence difference spectra of wild-type and P1 tryptophan variant antithrombins showed that the P1 tryptophan exhibited fluorescence properties characteristic of a solvent-exposed residue which were insignificantly affected by heparin activation. Moreover, all P1 variant antithrombins bound heparin with approximately 2-3-fold higher affinities than the wild type. These findings are consistent with the P1 mutations disrupting a P1 arginine-serpin body interaction which stabilizes the native low-heparin affinity conformation, but suggest that this interaction is of low energy and unlikely to limit the accessibility of the P1 residue. Together, these findings suggest that the P1 arginine residue is similarly accessible to proteinases in both native and heparin-activated states of the serpin and contributes similarly to the specificity of antithrombin for thrombin and factor Xa in the two serpin conformational states. Consequently, determinants other than the P1 residue are responsible for enhancing the specificity of antithrombin for the two proteinases when activated by heparin.

Heparin enhances the specificity of antithrombin for thrombin and factor Xa independent of the reactive center loop sequence. Evidence for an exosite determinant of factor Xa specificity in heparin-activated antithrombin

Heparin activates the primary serpin inhibitor of blood clotting proteinases, antithrombin, both by an allosteric conformational change mechanism that specifically enhances factor Xa inactivation and by a ternary complex bridging mechanism that promotes the inactivation of thrombin and other target proteinases. To determine whether the factor Xa specificity of allosterically activated antithrombin is encoded in the reactive center loop sequence, we attempted to switch this specificity by mutating the P6-P3' proteinase binding sequence excluding P1-P1' to a more optimal thrombin recognition sequence. Evaluation of 12 such antithrombin variants showed that the thrombin specificity of the serpin allosterically activated by a heparin pentasaccharide could be enhanced as much as 55-fold by changing P3, P2, and P2' residues to a consensus thrombin recognition sequence. However, at most 9-fold of the enhanced thrombin specificity was due to allosteric activation, the remainder being realized without activation. Moreover, thrombin specificity enhancements were attenuated to at most 5-fold with a bridging heparin activator. Surprisingly, none of the reactive center loop mutations greatly affected the factor Xa specificity of the unactivated serpin or the several hundred-fold enhancement in factor Xa specificity due to activation by pentasaccharide or bridging heparins. Together, these results suggest that the specificity of both native and heparin-activated antithrombin for thrombin and factor Xa is only weakly dependent on the P6-P3' residues flanking the primary P1-P1' recognition site in the serpin-reactive center loop and that heparin enhances serpin specificity for both enzymes through secondary interaction sites outside the P6-P3' region, which involve a bridging site on heparin in the case of thrombin and a previously unrecognized exosite on antithrombin in the case of factor Xa.

Differential Expression of Voltage-Gated K + Channel Genes in Arteries From Spontaneously Hypertensive and Wistar-Kyoto Rats

Abstract —Voltage-gated K + currents play an important role in determining membrane potential, intracellular Ca 2+ , and contraction in arterial smooth muscle. In this study, the expression of genes encoding voltage-gated K + channels of the Kv1.X family was compared in arteries from spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats (WKY). Expression of Kv1.X in thoracic aorta, mesenteric arteries, tail artery, and heart was determined, both qualitatively and quantitatively, by reverse transcription–polymerase chain reaction. Our results demonstrate distinct but overlapping patterns of expression in vascular tissues. In general, Kv1.2 and Kv1.5 were most highly represented, and the levels of Kv1.2 were significantly larger in all tissues from SHR. Levels of Kv1.5 in arteries did not differ significantly between strains but were greater in SHR heart. Moderate levels of Kv1.3 and Kvβ1.1 expression were also found in all tissues and were larger in SHR. Kv1.1 expression was not different between the 2 strains, and no significant expression of Kv1.4 (except in heart and aorta), Kv1.6, or Kvβ2.1 was observed in either strain. Kv1.2 and Kv1.5 transcripts represent ≈1 to 2 parts/10 5 of total mesenteric arterial RNA with ≈2- to 5-fold lower levels in aorta and tail artery. Whole-cell voltage-gated K + channel currents, recorded from mesenteric arterial myocytes, were larger in SHR than WKY (eg, at 0 mV: 7.3±0.8 versus 10.9±1.2 pA/pF). The voltage dependence of activation was more negative in SHR (V 0.5 : −20±4 mV versus −32±3 mV) but that of availability was not different. These results indicate that Kv1.X genes are differentially expressed between WKY and SHR (especially Kv1.2 and Kvβ1.1). These differences in gene expression are associated with a greater voltage-gated K + channel current density in SHR and shifted voltage-dependent activation compared with WKY. These differences may be a compensatory mechanism related to the membrane potential depolarization in SHR or some manifestation thereof.

The human inward rectifier K(+) channel subunit kir5.1 (KCNJ16) maps to chromosome 17q25 and is expressed in kidney and pancreas

A novel human Kir5.1 (inward rectifier K+ channel subunit, gene name KCNJ16) was identified through database searches. This human KCNJ16 was mapped to chromosome 17q25. The full-length cDNA was identified and its genomic structure was determined. Tissue distribution studies showed that human KCNJ16 is significantly expressed in human kidney, pancreas and thyroid gland. In situ hybridization revealed expression in convoluted tubule cells of kidney and in the acinar and ductal cells of pancreas. These suggest that human Kir5.1 may be involved in the regulation of fluid and pH balance, thus making it a potential therapeutic target for hypertension, renal failure, or pancreatic disease.

Cloning and functional expression of two families of beta-subunits of the large conductance calcium-activated K+ channel

We report here a characterization of two families of calcium-activated K(+) channel beta-subunits, beta2 and beta3, which are encoded by distinct genes that map to 3q26.2-27. A single beta2 family member and four alternatively spliced variants of beta3 were investigated. These subunits have predicted molecular masses of 27. 1-31.6 kDa, share approximately 30-44% amino acid identity with beta1, and exhibit distinct but overlapping expression patterns. Coexpression of the beta2 or beta3a-c subunits with a BK alpha-subunit altered the functional properties of the current expressed by the alpha-subunit alone. The beta2 subunit rapidly and completely inactivated the current and shifted the voltage dependence for activation to more polarized membrane potentials. In contrast, coexpression of the beta3a-c subunits resulted in only partial inactivation of the current, and the beta3b subunit conferred an apparent inward rectification. Furthermore, unlike the beta1 and beta2 subunits, none of the beta3 subunits increased channel sensitivity to calcium or voltage. The tissue-specific expression of these beta-subunits may allow for the assembly of a large number of distinct BK channels in vivo, contributing to the functional diversity of native BK currents.

A viable ubiquitin-activating enzyme mutant for evaluating ubiquitin system function in Saccharomyces cerevisiae

Ligation of proteins to ubiquitin requires activation of ubiquitin by E1, the ubiquitin-activating enzyme. Mutant alleles of E1 in mammalian cells have been crucial for dissecting the contribution of the ubiquitin system to cell function. Comparable mutants have been unavailable for Saccharomyces cerevisiae. Here we describe the isolation and characterization of a hypomorphic allele of S. cerevisiae E1. Protein modification by ubiquitin is strongly impaired in the mutant, inhibiting degradation of ubiquitin-proteasome pathway substrates as well as ubiquitin-dependent but proteasome-independent degradation of membrane receptors. This allele will be a useful tool for evaluating the ubiquitin-dependence of cellular processes in yeast, even those in which the proteasome is not involved.

Role of arginine 129 in heparin binding and activation of antithrombin

The contribution of Arg(129) of the serpin, antithrombin, to the mechanism of allosteric activation of the protein by heparin was determined from the effect of mutating this residue to either His or Gln. R129H and R129Q antithrombins bound pentasaccharide and full-length heparins containing the antithrombin recognition sequence with similar large reductions in affinity ranging from 400- to 2500-fold relative to the control serpin, corresponding to a loss of 28-35% of the binding free energy. The salt dependence of pentasaccharide binding showed that the binding defect of the mutant serpin resulted from the loss of approximately 2 ionic interactions, suggesting that Arg(129) binds the pentasaccharide cooperatively with other residues. Rapid kinetic studies showed that the mutation minimally affected the initial low affinity binding of heparin to antithrombin, but greatly affected the subsequent conformational activation of the serpin leading to high affinity heparin binding, although not enough to disfavor activation. Consistent with these findings, the mutant antithrombin was normally activated by heparin for accelerated inhibition of factor Xa and thrombin. These results support an important role for Arg(129) in an induced-fit mechanism of heparin activation of antithrombin wherein conformational activation of the serpin positions Arg(129) and other residues for cooperative interactions with the heparin pentasaccharide so as to lock the serpin in the activated state.

Surgical resection improves survival in the treatment of early gastric lymphomas

Gastric lymphomas are a relatively rare form of malignancy and controversy about their optimum treatment still exists. To date, there have been no studies directly comparing results of medical therapy alone versus a combination of surgery plus medical therapy. We reviewed our experience in the three teaching hospitals of the University of Massachusetts Medical School to determine the role of surgery in the management of early gastric lymphoma. Statistics were evaluated by means of chi-square, log-rank, and Kaplan-Meier curve analysis where appropriate. Using tumor registry data, 39 patients were treated for early disease at our medical school from 1980 to 1998. Patients treated with surgery plus chemotherapy and radiation had a 90% 5-year survival compared to patients who received chemotherapy and radiation alone (55% 5-year survival; P <0.01). When we compared all patients on an intention-to-treat basis (patients preoperatively thought to have early-stage disease), there was still a significant survival benefit with the addition of surgery to their management. Because this is an uncommon disease, there are no large prospective studies examining treatment. Based on our retrospective experience, surgical resection should be considered an important adjunct in the treatment of gastric lymphomas in early-stage disease.

The Saccharomyces cerevisiae ubiquitin-proteasome system

Our studies of the yeast ubiquitin-proteasome pathway have uncovered a number of general principles that govern substrate selectivity and proteolysis in this complex system. Much of the work has focused on the destruction of a yeast transcription factor, MAT alpha 2. The alpha 2 protein is polyubiquitinated and rapidly degraded in alpha-haploid cells. One pathway of proteolytic targeting, which depends on two distinct endoplasmic reticulum-localized ubiquitin-conjugating enzymes, recognizes the hydrophobic face of an amphipathic helix in alpha 2. Interestingly, degradation of alpha 2 is blocked in a/alpha-diploid cells by heterodimer formation between the alpha 2 and a1 homeodomain proteins. The data suggest that degradation signals may overlap protein-protein interaction surfaces, allowing a straightforward steric mechanism for regulated degradation. Analysis of alpha 2 degradation led to the identification of both 20S and 26S proteasome subunits, and several key features of proteasome assembly and active-site formation were subsequently uncovered. Finally, it has become clear that protein (poly) ubiquitination is highly dynamic in vivo, and our studies of yeast de-ubiquitinating enzymes illustrate how such enzymes can facilitate the proteolysis of diverse substrates.

Efficacy and safety of ampicillin/sulbactam and cefuroxime in the treatment of serious skin and skin structure infections in pediatric patients. UNASYN Pediatric Study Group

BACKGROUND

Pediatric skin and skin structure infections are often polymicrobial and require empiric therapy effective against pathogens that may be resistant to many antimicrobial agents. The present study tested the efficacy and safety of a parenteral beta-lactam/beta-lactamase inhibitor combination, ampicillin/sulbactam, and a beta-lactamase-stable cephalosporin, cefuroxime, in serious pediatric skin and skin structure infections requiring hospitalization and parenteral antimicrobial therapy.

METHODS

This was a multicenter, randomized, prospective, comparative open label trial that enrolled patients 3 months through 11 years of age. Patients received 150 to 300 mg/kg/day ampicillin/sulbactam in equally divided intravenous doses every 6 h. Cefuroxime was given in a dosage of 50 to 100 mg/kg/day either intravenously or intramuscularly in equally divided doses every 6 or 8 h. Maximum treatment was not to exceed 14 days. Patients could receive subsequent oral antimicrobial treatment at the investigator's discretion.

RESULTS

At final evaluation for clinical efficacy, 78.0% (n = 46) of the 59 evaluable patients who received ampicillin/sulbactam were cured and 22.0% (n = 13) were improved. The respective values for the 39 evaluable patients treated with cefuroxime were 76.9% (n = 30) and 23.1% (n = 9). At the end of treatment all pathogens were eradicated from 93.2% (n = 55) of 59 patients treated with ampicillin/sulbactam and from 100% of 39 who received cefuroxime. There were no significant differences between treatments in clinical or bacteriologic efficacy. Both ampicillin/sulbactam and cefuroxime were well-tolerated.

CONCLUSION

Both ampicillin/sulbactam and cefuroxime provide safe and effective parenteral antibiotic therapy in pediatric patients with serious skin and skin structure infections.

[A method for intermittent hypoxic exposures in the combined treatment of bronchial asthma patients]

The method of intermittent increasing normobaric isocapnic hypoxia was used for the treatment of bronchial asthma. The parameters of respiration, metabolism, free-radical processes and immune system were monitored before and after training. The therapeutic diagnostic complex "Hypotron" (Ukraine), which allowed to determine the individual reactivity of the patient's respiratory system, tolerance to hypoxia, and to choose an optimal program of treatment, was used. The hypoxic training resulted in considerable increase of lung vital capacity, maximal ventilation and forced expired velocity. Normalization of initially increased free radical processes, accompanied by a decrease in the lipid peroxidation products was observed. The hypoxic training positively influenced specific and nonspecific immunological status, and appeared to be associated with a far better stimulation of lymphocytes and neutrophils.

Degradation signal masking by heterodimerization of MATalpha2 and MATa1 blocks their mutual destruction by the ubiquitin-proteasome pathway

Proteolysis by the ubiquitin-proteasome pathway is often regulated, but the mechanisms underlying such regulation remain ill-defined. In Saccharomyces cerevisiae, cell type is controlled by the MAT transcription factors. The alpha2 repressor is a known ubiquitin pathway substrate in alpha haploid cells. We show that a1 is rapidly degraded in a haploids. In a/alpha diploids, alpha2 and a1 are stabilized by heterodimerization. Association depends on N-terminal coiled-coil interactions between a1 and alpha2. Residues in alpha2 important for these interactions overlap a critical determinant of an alpha2 degradation signal, which we delimit by extensive mutagenesis. Our data provide a detailed description of a natural ubiquitin-dependent degradation signal and point to a molecular mechanism for regulated turnover in which proteolytic signals are differentially masked in alternative multiprotein complexes.

Role of allosteric: zinc interdomain region of the regulatory subunit in the allosteric regulation of aspartate transcarbamoylase from Escherichia coli

The hydrophobic interface between the allosteric and the zinc domains of the regulatory subunit of aspartate transcarbamoylase has previously been implicated in the heterotropic ATP activation of the enzyme. The present work shows that this interface also affects CTP and CTP-UTP inhibition and proposes a structural explanation for the effects. Mutant enzymes derived from nonselective mutagenesis of residues r101-r106 (residues that contribute part of the interface) displayed a variety of homotropic and heterotropic effects. The cooperative behavior of the enzymes was affected, as indicated by reduced aspartate S0.5 values and apparent Hill coefficient values for V106L, V106L/N105S, and I103F/R102C. In addition, both ATP activation and CTP inhibition were significantly reduced and CTP+UTP synergistic inhibition was decreased in these mutants. The D104G mutant enzyme was subject to inhibition by CTP andCTP+UTP, but was not activated by ATP. Finally, the I103T mutant enzyme had an increased S0.5 value of 11.5 mM and displayed altered effector responses: ATP acted as an inhibitor, and the CTP+UTP synergistic inhibition was reduced. Most of these allosteric variations can be explained in terms of perturbations to the "tongue and groove" hydrophobic interface between the allosteric and the zinc domains and a consequent impact on a second interface ("reg1:cat4") between regulatory and catalytic subunits.

Paradigms and expectations: the nature of research and diagnostics

Researchers are judged by their best work. No matter what disasters happen at the researcher's bench, there is time to repeat experiments, discard ambiguous data and work steadily toward a clearer understanding of the research problem. The work practices of researchers are matters of personal choice, because the process of peer review prior to publication considers only the work that is reported and not all work done by the researcher. On the other hand, the diagnostician's credibility is directly linked to every experiment performed, because a customer is waiting for the result. This paper contrasts aspects of the work of researchers and diagnosticians and concludes that researchers could benefit from understanding the framework within which diagnosticians operate.

Characterization of rhesus cytomegalovirus genes associated with anti-viral susceptibility

Studies were initiated to determine whether rhesus cytomegalovirus (RhCMV)-infected macaques could serve as an animal model for evaluating anti-CMV compounds, as macaques have a naturally occurring CMV that is similar to human CMV (HCMV). Utilizing plaque reduction assays, RhCMV was tested to anti-viral susceptibility. By these assays. RhCMV displayed anti-viral susceptibility to ganciclovir at a 50% effective dose (ED50) of 0.8 microM, acyclovir at an ED50 of 15 microM, and foscarnet at an ED50 of 250 microM. By Southern blot analysis with HCMV-UL97 (phosphotransferase) and DNA polymerase (pol) genes as probes, we isolated viral DNA fragments that strongly hybridized. DNA sequence analysis of these DNA fragments revealed two open reading frames with homology to HCMV UL97 and DNA polymerase. Steady-state RNA analysis revealed that the RhCMV UL97 homologue and pol genes are transcribed as early late and early genes, respectively. Comparison against HCMV showed the RhCMV UL97 homologue exhibits 54.4% amino acid (aa) sequence identity to HCMV UL97 and the RhCMV DNA polymerase 59.2% aa sequence identity to HCMV DNA polymerase. Results from anti-viral assays and molecular characterization of these two viral genes suggest that RhCMV-infected rhesus macaques should serve as an excellent animal model for evaluating future anti-CMV compounds.

Strychnine-like multifocal myoclonus and seizures in extremely high-dose opioid administration: treatment strategies

While occasional myoclonic jerks are prevalent in cancer patients receiving opioids, severe myoclonic jerks and seizures due to opioids are uncommon. In this retrospective case series, we describe five cancer patients with refractory cancer pain and severe neuroexcitatory toxicity associated with extremely high-dose opioid therapy to characterize better the syndrome, its treatment, and its outcome. Two patients died following seizures, but three patients recovered following prompt treatment with parenteral midazolam infusions and rotation to alternative opioids. Possible mechanisms and treatment options for this potentially lethal clinical syndrome are reviewed. The authors conclude that severe multifocal myoclonus and seizures associated with extremely high-dose opioid therapy are life-threatening, and respond to parenteral midazolam infusion, rotation to alternative opioids, and aggressive supportive care.

Apparent formation of sodium dodecyl sulfate-stable complexes between serpins and 3,4-dichloroisocoumarin-inactivated proteinases is due to regeneration of active proteinase from the inactivated enzyme

Protein proteinase inhibitors of the serpin family were recently reported to form SDS-stable complexes with inactive serine proteinases modified at the catalytic serine with 3, 4-dichloroisocoumarin (DCI) that resembled the complexes formed with the active enzymes (Christensen, S., Valnickova, Z., Thogersen, I. B. , Pizzo, S. V., Nielsen, H. R., Roepstorff, P., and Enghild, J. J. (1995) J. Biol. Chem. 270, 14859-14862). The discordance between these findings and other reports that similar active site modifications of serine proteinases block the ability of serpins to form SDS-stable complexes prompted us to investigate the mechanism of complex formation between serpins and DCI-inactivated enzymes. Both neutrophil elastase and beta-trypsin inactivated by DCI appeared to form SDS-stable complexes with the serpin, alpha1-proteinase inhibitor (alpha1PI), as reported previously. However, several observations suggested that such complex formation resulted from a reaction not with the DCI enzyme but rather with active enzyme regenerated from the DCI enzyme by a rate-limiting hydrolysis reaction. Thus (i) complex formation was blocked by active site-directed peptide chloromethyl ketone inhibitors; (ii) the kinetics of complex formation indicated that the reaction was not second order but rather showed a first-order dependence on DCI enzyme concentration and zero-order dependence on inhibitor concentration; and (iii) complex formation was accompanied by stoichiometric release of a peptide having the sequence SIPPE corresponding to cleavage at the alpha1PI reactive center P1-P1' bond. Quantitation of kinetic constants for DCI and alpha1PI inactivation of human neutrophil elastase and trypsin and for reactivation of the DCI enzymes showed that the observed complex formation could be fully accounted for by alpha1PI preferentially reacting with active enzyme regenerated from DCI enzyme during the reaction. These results support previous findings of the critical importance of the proteinase catalytic serine in the formation of SDS-stable serpin-proteinase complexes and are in accord with an inhibitory mechanism in which the proteinase is trapped at the acyl intermediate stage of proteolysis of the serpin as a substrate.

Effect of individual carbohydrate chains of recombinant antithrombin on heparin affinity and on the generation of glycoforms differing in heparin affinity

Two major glycoforms of recombinant antithrombin which differ 10-fold in their affinity for the effector glycosaminoglycan, heparin, were previously shown to be expressed in BHK or CHO mammalian cell lines (I. Björk, et al., 1992, Biochem. J. 286, 793-800; B. Fan et al., 1993, J. Biol. Chem. 268, 17588-17596). To determine the source of the glycosylation heterogeneity responsible for these different heparin-affinity forms, each of the four Asn residue sites of glycosylation, residues 96, 135, 155, and 192, was mutated to Gln to block glycosylation at these sites. Heparin-agarose chromatography of the four antithrombin variants revealed that Gln 96, Gln 135, and Gln 192 variants still displayed the two functional heparin-affinity forms previously observed with the wild-type inhibitor, whereas the Gln 155 variant showed only a single functional high heparin affinity form. These results demonstrate that heterogeneous glycosylation of Asn 155 of recombinant antithrombin is responsible for generating the low heparin affinity glycoform. Analysis of heparin binding to the higher heparin affinity forms of the four variants showed that all exhibited increased heparin affinities of two- to sevenfold compared to wild-type higher heparin affinity form or to plasma antithrombin, with the Gln 135 variant showing the largest effect on this affinity. The extent of heparin-affinity enhancement was correlated with the distance of the mutated glycosylation site to the putative heparin-binding site in the X-ray structure of antithrombin. All variants displayed normal kinetics of thrombin inhibition in the absence and presence of saturating heparin, indicating that the carbohydrate chains solely affected heparin binding and not heparin-activation or proteinase-binding functions. These results indicate that all carbohydrate chains of recombinant antithrombin adversely affect heparin-binding affinity to an extent that correlates with their relative proximity to the putative heparin-binding site in antithrombin.

A fosmid-based genomic map and identification of 474 genes of the hyperthermophilic archaeon Pyrobaculum aerophilum

We have constructed a physical map of the approximately 1.7-Mb genome of the hyperthermophilic archaeon Pyrobaculum aerophilum. Derived from a 12x coverage genomic fosmid library with an average insert size of 36 Kb, the map consists of a single circular contig of 96 overlapping fosmid clones with 211 markers ordered along them. One hundred of the sequence markers have strong similarities to known genes. Many overlaps were also checked using restriction fingerprint analysis. This map is an important step in the elucidation of the sequence of the entire genome of Pyrobaculum aerophilum. To this end we have determined more than 95% of the genome with 15,000 random sequences. Each sequence has been screened against the public sequence databases to identify similarities to known genes. We report here a list of the 474 putative genes we have identified.

IK of rabbit ventricle is composed of two currents: evidence for IKs

The delayed rectifier K+ current (IK) in rabbit heart has long been thought to consist of only a single, rapidly activating, dofetilide-sensitive current, IKr. However, we find that IK of rabbit ventricular myocytes actually consists of both rapid and slow components, IKr and IKs, respectively, that can be isolated pharmacologically. Thus, after complete blockade of IKr with dofetilide, the remaining current, IKs, is homogeneous as judged by an envelope of tails test. IKs activates and deactivates slowly, continues to activate during sustained depolarizations, has a half-activation potential of 7.0 +/- 0.8 mV and slope factor of 11.0 +/- 0.7 mV, reverses at -77.2 +/- 1.3 mV (extracellular K+ concentration = 4 mM), is increased by removing extracellular K+, and is enhanced by isoproterenol and stocked by azimilide. Northern analysis demonstrates that the minK (IsK) gene, which encodes a subunit of the channel that underlies the IKs current, is expressed in rabbit heart. Expression of the rabbit protein in Xenopus oocytes elicits a slowly activating, voltage-dependent current, IsK, similar to those expressed previously from mouse, rat, guinea pig, and human genes. The results demonstrate that IKs is present in rabbit ventricle and therefore contributes to cardiac repolarization in this species.

The human P2x1 receptor: molecular cloning, tissue distribution, and localization to chromosome 17

A human urinary bladder cDNA library was screened with a rat P2x purinoceptor probe. A full-length cDNA was isolated, and like its rat homologue, the deduced protein consists of 399 amino acids (M(r) = 44980 Da), contains two hydrophobic, putative transmembrane, domains flanking a large presumed extracellular loop, and represents the P2x1 subtype of this multigene family (approximately 89% amino acid sequence identity to rat P2x1, but only 40-50% identity to rat P2x2-4). Expression of the P2x1 gene in human bladder was confirmed by Northern analysis, which demonstrated a major transcript of approximately 2.9 kb. Transcripts were also found in a variety of other tissues including adult peripheral leukocytes, pancreas, spleen, prostate, small intestine, colon, testis, and ovary, and in fetal liver. The gene encoding the human P2x1 receptor was localized to chromosome 17 by Southern analysis of DNAs isolated from a panel of somatic cell hybrids. The results support a role for P2x purinoceptors in the regulation of human bladder function.

Algorithms for finding the axis of a helix: fast rotational and parametric least-squares methods

Several methods for finding the axis of a helix are presented and compared. The most accurate determines the helix axis as the axis of rotation necessary to map point i to point i + 1 of the helix. The fastest method calculates the helix axis as the best-fit line through the coordinates by a three-dimensional parametric linear least-squares algorithm, taking advantage of the sequential nature of the data.

A new approach to chronic pain in the ED

Patients presenting to emergency departments (EDs) for primary management of chronic or recurrent nonmalignant pain conditions and their physicians frequently report dissatisfaction, in part because of the impressions created by a small percentage of such patients that frequently visit EDs requesting opioids. Treating such patients with opioids is contrary to many published guidelines, but refusing them increases dissatisfaction. Narcotic registers serve to label patients who are suspected of seeking drugs, thus creating anxiety and often distrust in health care professionals treating them. The four Calgary adult EDs have developed a system that will attempt to remove labels associated with some of these patients, insure communication between patients, their family doctors, and ED staff, and facilitate optimal care of the patients' real problems, be they difficult home management of pain, drug dependence or addiction, or other social issues. Emphasis will be shifted to home management and the family doctor's office. If successful, the system will minimize ED visits by frequent attendees seeking medication for pain control, and should also decrease overall expenditure to the health care system.

Functional role of the beta subunit of high conductance calcium-activated potassium channels

Mammalian high conductance, calcium-activated potassium (maxi-K) channels are composed of two dissimilar subunits, alpha and beta. We have examined the functional contribution of the beta subunit to the properties of maxi-K channels expressed heterologously in Xenopus oocytes. Channels from oocytes injected with cRNAs encoding both alpha and beta subunits were much more sensitive to activation by voltage and calcium than channels composed of the alpha subunit alone, while expression levels, single-channel conductance, and ionic selectivity appeared unaffected. Channels from oocytes expressing both subunits were sensitive to DHS-I, a potent agonist of native maxi-K channels, whereas channels composed of the alpha subunit alone were insensitive. Thus, alpha and beta subunits together contribute to the functional properties of expressed maxi-K channels. Regulation of co-assembly might contribute to the functional diversity noted among members of this family of potassium channels.

Efficient infection from cDNA clones of cucumber mosaic cucumovirus RNAs in a new plasmid vector

Full-length cucumber mosaic cucumovirus (CMV) cDNAs were cloned into a new plasmid vector containing a modified plant virus promoter designed to transcribe the inserted sequence from its first nucleotide. cDNA copies of CMV strain Q (Q-CMV) genomic RNAs 1, 2 and 3 cloned into this vector were infectious when inoculated together, producing symptoms indistinguishable from those caused by wildtype Q-CMV infection. The infectivity of the clones could be substantially increased by excision of the viral insert together with the transcriptional promoter and terminator prior to inoculation. A diagnostic but silent mutation was introduced into the RNA 2 cDNA and found to be stably maintained in viral infection, allowing distinction of the recombinant virus from native contaminants. The infectious cDNA clones supported the replication of CMV satellite RNA when co-inoculated with biologically active Q-CMV satellite RNA transcripts. Using the infectious cDNAs described, it was found that a newly-identified overlapping gene (2b) encoded by Q-CMV RNA 2 was not essential for either systemic viral infection of Nicotiana glutinosa or replication of the satellite RNAs.

Selective suppression of cytochrome P-450 gene expression by interleukins 1 and 6 in rat liver

Inflammatory stimuli suppress constitutive hepatic expression of the CYP2C11 and CYP2C12 genes in male and female rat livers, respectively. We have shown previously that injection of interleukin-1 (IL1), but not interleukin-6 (IL6), to female rats also suppresses CYP2C12. In the present study, we examined the effects of these cytokines on CYP2C12 expression in rat hepatocyte cultures, and their in vivo effects on expression of multiple cytochrome P-450 (P450) gene products in male rat livers. IL1 suppressed the expression of CYP2C12 mRNA and protein in hepatocytes cultured on Matrigel in the presence of growth hormone. No consistent effect of IL6 was observed. Maximal suppression of CYP2C12 mRNA after 24 h of IL1 treatment reached 12 and 32% of control levels in two separate experiments. The approximate ED50 for IL1 was 5 ng/ml. CYP2C12 protein was suppressed to 28% of control levels as early as 12 h after IL1 treatment. Injection of IL1, low doses of dexamethasone, or both, in male rats produced decreases in total P450, and in CYP3A2 and CYP2C11 mRNA and protein expression similar to effects previously seen for CYP2C12 expression in females. CYP2E1 mRNA and protein was significantly suppressed only by the combination of IL1 and dexamethasone. IL6 treatment of male rats down-regulated the CYP2C11 and CYP2E1 mRNAs at a dose of 4.5 micrograms/kg, which was lower than that required to induce haptoglobin mRNA, a prototype acute phase gene product. CYP2C11 protein content of the microsomes was also decreased by IL6 treatment, with a slower time-course than for suppression of its mRNA. No significant effects of IL6 treatment were seen on CYP3A2 mRNA or CYP3A2/1 proteins. These results demonstrate that IL1 and IL6 treatments in vivo differentially affect subsets of P450 gene products in rat liver.

Primary sequence and immunological characterization of beta-subunit of high conductance Ca(2+)-activated K+ channel from smooth muscle

The charybdotoxin receptor, purified from bovine tracheal smooth muscle, consists of two subunits (alpha and beta) and, when reconstituted into planar lipid bilayers, forms functional high conductance Ca(2+)-activated K+ channels. Amino acid sequence, obtained from proteolytic fragments of the beta-subunit, was used to design oligonucleotide probes with which cDNAs encoding this protein were isolated. The cDNAs encode a protein of 191 amino acids that contains two hydrophobic (putative transmembrane) domains and bears little sequence homology to subunits of other known ion channels. Site-directed antisera, raised against putative extracellular epitopes of this protein, specifically immunoprecipitated 125I-labeled Bolton-Hunter beta-subunit as well as [125I]charybdotoxin-cross-linked beta-subunit. Under nondenaturing conditions, however, these anti-beta sera immunoprecipitated a complex consisting of both the alpha- and beta-subunits. The data demonstrate that, in vivo, the high conductance Ca(2+)-activated K+ channel exists as a multimer containing both alpha- and beta-subunits, and this cDNA represents the first beta-subunit of a potassium channel cloned to date. Furthermore, we demonstrate that the cloned protein is the subunit to which charybdotoxin is specifically and covalently incorporated when cross-linked to the channel.