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T O'Hare

Publications and source records attributed to T O'Hare.

At least 19 recordsLinked to original sources
PubMed1999

Cutting edge: proteasome involvement in the degradation of unassembled Ig light chains.

Several studies on disposal of nonsecreted Ig L chains have identified the endoplasmic reticulum as the site of degradation. Here, we examine degradation of a nonsecreted Ig L chain, T15L, and an experimentally endoplasmic reticulum-retained secretion-competent L chain, D16L, in the absence of H chains. We demonstrate that 1) degradation is specifically impaired by the proteasome-specific inhibitors carboxybenzyl-leucyl-leucyl-leucine vinyl sulfone (Z-L3VS) and lactacystin, 2) L chain degradation occurs early in the biosynthetic pathway, and 3) degradation does not require vesicular transport. Our findings indicate that previous assertions of L chain disposal within the endoplasmic reticulum must be modified. To our knowledge, we provide the first direct evidence supporting a new paradigm for removal of nonsecreted Ig L chains via dislocation to cytosolic proteasomes.

Animals↗
PubMed1999

Replacements in the exposed loop of the T15 antibody VH CDR2 affect carrier recognition of PC-containing pathogens.

A panel of mutant antibodies of the phosphocholine (PC)-binding antibody, T15, was tested for binding to PC-protein, Streptococcus pneumoniae, Trichinella spiralis and Ascaris suum. Relative to wildtype T15, all the mutant antibodies showed differential recognition of the panel of PC-associated antigens. These mutant antibodies contain amino acid replacements in the CDR2 region of the heavy chain variable region, indicating the importance of CDR2 in recognition of carrier determinants. A model of T15 is shown that illustrates the strategic placement of mutations that could allow interaction with determinants associated with PC. A direct implication of this finding is that the T15 antibody combining site accommodates structures larger than phosphocholine and that recognition of associated carrier determinants could be a significant force in shaping the immune response to PC-containing pathogens.

Amino Acid Sequence↗
PubMed1999

Anterior subannular T-tube for long-term middle ear ventilation during tympanoplasty.

OBJECTIVE: A technique for providing long-term ventilation of the middle ear (ME) during tympanoplasty is described, and the results using this technique in 20 patients with chronic Eustachian tube dysfunction (ETD) are reported. STUDY DESIGN: This study was a retrospective, nonrandomized case review. SETTING: This study was conducted at an otology clinic in a tertiary referral center. PATIENTS: Twenty consecutive patients who underwent tympanoplasty with ETD, adhesive otitis media, or chronic otitis media with perforation were included in this study. INTERVENTION: All patients had a subannular T-tube placed anteriorly at the time of tympanoplasty for long-term ventilation of the ME space. MAIN OUTCOME MEASURES: The two main outcome measures were tube position and patency. Preoperative and postoperative hearing levels were also tested in most patients, and any complications were documented. RESULTS: Twenty patients (20 ears) received anterior subannular T-tubes at the time of tympanoplasty. Fourteen females and 6 males were evaluated (median age, 36 years; range, 7 to 72 years). All patients had ETD; 7 had adhesive otitis media, 10 had chronic otitis media, 8 had cholesteatoma, and 2 had cleft palate. All patients had conductive hearing loss and previous surgery. All patients underwent tympanoplasty; 11 had concomitant ossiculoplasty, and 5 had mastoidectomy. Follow-up ranged from 8 to 22 months (mean, 13.4 months). One patient was lost to follow-up. One tube extruded after 16 months. Two patients had persistent mild retraction of the tympanic membrane. All other tubes are patent and have not migrated or plugged. There has been no evidence of anterior blunting or ingrowth of epithelium around the tube. CONCLUSIONS: Anterior subannular T-tube placement is a simple, safe, and effective alternative for long-term ME ventilation in patients in whom standard transtympanic sites are not available. At their last follow-up visit, all but one patient had a patent tube. All MEs were aerated. This technique offers the advantage of ease of placement during simultaneous tympanoplasty, mastoidectomy, or ossiculoplasty. Longer follow-up is necessary to confirm these initial findings.

Adolescent↗
PubMed1998

A simple method for determining K(A)s of both low and high affinity IgG antibodies.

A rapid and convenient method for measuring affinity constants (K(A)) of IgG antibody-hapten complexes is described. A key advantage of this method is its suitability for quantification of both low and high affinity interactions. A comparison is made of the K(A)s of the low affinity anti-phosphocholine (PC) antibody T15 (K(A) = 2.9 x 10(5) M(-1)) and five heavy chain complementarity determining region 2 (HCDR2) mutant antibodies expressed as IgG2b transfectants. As a demonstration of the general applicability of the technique, colchicine binding to the high affinity monoclonal IgG2a antibody C44 (K(A) = 1.5 x 10(9) M(-1)) is measured also; thus the assay is applicable over a four-log range of affinities. The assay, based upon use of fixed Staphylococcus aureus Cowan I strain cells as an adsorbent for antibody-radiolabeled antigen complexes, is conducted over a range of hapten concentrations at constant antibody concentration. The K(A) is obtained by Scatchard analysis.

Antibodies, Monoclonal↗
PubMed1998

Harmful somatic mutations: lessons from the dark side.

The ability of somatic mutation to modify the course of an immune response is well documented. However, emphasis has been placed almost exclusively on the ability of somatic mutation to improve the functional characteristics of representative antibodies. The harmful effects of somatic mutation, its dark side, have been far less well characterized. Yet evidence suggests that the number of B cells directed to wastage pathways as a result of harmful somatic mutation probably far exceeds the number of cells whose antibodies have been improved. Here we review our recent findings in understanding the structural and functional consequences of V-region mutation.

Animals↗
PubMed1998

Substance abuse among Southeast Asians in the U.S.: implications for practice and research.

The literature on Asian-American substance use has shown a general increase in consumption and related problems due, in part, to the effects of acculturation toward U.S. drinking norms. Southeast Asians are the most recent of Asian groups to come to the U.S., and have done so following an immigration and refugee experience that was among the most traumatic in recent memory resulting in significant levels of psychosocial distress. The combined influences of mental health disorders, which frequently co-occur with substance abuse, and acculturation pressures suggest that a significant increase in substance abuse problems may be in progress for Southeast Asian immigrants. Preliminary evidence appears to bear out this hypothesis. The current article outlines the literature on substance abuse among Vietnamese, Cambodians and Laotians in the U.S., and makes tentative recommendations for assessment, treatment and future research.

Acculturation↗
PubMed1997

Functional characterization of an epidermal growth factor receptor/RET chimera.

The RET (recombined in transfection) gene encodes a receptor tyrosine kinase homolog involved in innervation of the gut and renal development. A chimeric epidermal growth factor receptor (EGFR)/RET receptor was constructed which contained the extracellular and transmembrane domains of the EGF receptor fused to the intracellular domain of RET. This construct was expressed in NIH 3T3 cells, and the functional properties of the receptor were characterized and compared with those of the wild type EGF receptor. Whereas the EGF receptor exhibited both high and low affinity binding sites for 125I-EGF, the EGFR/RET chimera exhibited only low affinity binding of 125I-EGF. The chimera was able to internalize EGF more rapidly than the wild type EGF receptor and recycled to the cell surface at twice the rate of the EGF receptor. Pulse-chase experiments indicated that EGF stimulated the degradation of the wild type EGF receptor but had no effect on the rate of degradation of the EGFR/RET receptor. The combination of increased recycling and decreased degradation resulted in the relatively inefficient down-regulation of the EGFR/RET chimera. Incubation of cells expressing the wild type EGF receptor with phorbol 12-myristate 13-acetate led to a reduction in 125I-EGF binding and a loss in EGF-stimulated tyrosine phosphorylation. However, phorbol 12-myristate 13-acetate treatment had only a limited effect on EGF binding and EGF-stimulated tyrosine kinase activity in cells expressing EGFR/RET chimeras. These findings suggest that the ret tyrosine kinase is not regulated by many of the common mechanisms used to terminate signaling via growth factor receptors. Such persistent activation of the Ret tyrosine kinase may be relevant to the physiological function of Ret in cells that normally express this growth factor receptor.

3T3 Cells↗
PubMed1997

The interest of trainees in working with seriously mentally ill persons.

Working with persons who have severe and persistent mental illness has generally not been a preferred career track for prospective mental health professionals. Most of the literature has focused on the recruitment of psychiatrists. This paper reports the results of 78 students in Rhode Island representing three allied mental health professions-social work, psychology, and nursing. Significant differences were found in training environments and learning activities, in interests in working with various diagnostic groups, and in rating the relative importance of both client problems as well as interventions strategies. Implications for future academic-mental health linkages are suggested.

Adult↗
PubMed1996

Kinamycin acetyltransferase I from Streptomyces murayamaensis, an apparently large, membrane-associated enzyme.

Identification and initial characterization of an apparently large, membrane-associated multifunctional enzyme, kinamycin acetyltransferase I (KAT I), is described. KAT I activity was enriched 29-fold over the level in cell-free extracts of Streptomyces murayamaensis. Two acetyltransferase activities catalyzing acetyl coenzyme A dependent conversion of kinamycin F and E to kinamycin E and D, respectively, were inseparable in the course of the partial purification. Partial purification involved separation of KAT I from cytosolic proteins by differential ultracentrifugation, solubilization with 0.5% CHAPS zwitterionic detergent followed by ultracentrifugation, and Sephacryl S400 gel filtration chromatography of the resulting supernatant.

Acetyltransferases↗
PubMed1996

Fear of AIDS and homophobia: implications for direct practice and advocacy.

Studies of health care trainees and professionals have demonstrated that their level of empathy and caring is negatively affected by the knowledge that the person being treated is homosexual, in part because of stigma associated with HIV infection and AIDS. The survey discussed in this article examined the relationship between homophobia and the fear of AIDS within the context of several categorical questions. Gender differences in attitudes were also examined. Respondents who more liberally endorsed rights for gay men and lesbians were less homophobic and had less fear of AIDS. Suggestions are made for sensitizing social workers to the inhibitory effects of homophobia and fear of AIDS when working with HIV-infected clients or people in the gay community.

Acquired Immunodeficiency Syndrome↗
PubMed1995

The current status of academic-mental health linkages in Rhode Island.

The purpose of this study is to describe the current status of academic-public mental health linkages in the State of Rhode Island by querying key informants concerning their opinions in the following areas: clinical orientation and preferred clinical interventions, specific approaches to academic-mental health linkages, training and educational opportunities, obstacles to a career working with persons who have persistent and severe mental illness, and recommendations to improve academic-mental health linkages. Forty-eight of sixty key informants, among them academics, mental health administrators, clinical practitioners and consumer advocates, responded to the mailed survey. More than half the respondents rated affective disorders, schizophrenia and substance abuse to be their highest concern as professionals; most subscribed to biological models of mental illness as well as a variety of prevailing treatment strategies employed in the care of persons with severe mental illness; generally they rated the current status of academic-mental health linkages to be low, but recommended a range of remedies to improve and increase collaborative efforts.

Community Mental Health Services↗
PubMed1995

Mental health problems and alcohol abuse: co-occurrence and gender differences.

A growing body of research has demonstrated that alcohol abuse co-occurs with a broad range of mental health problems. To date, however, there is a scarcity of data concerning the co-occurrence of alcohol abuse and other problems in people who seek mental health outpatient services and, consequently, about gender differences among them. The present study surveyed 376 clients receiving outpatient services at a mental health center. Results demonstrate that women self-reported significantly more psychophysiological distress and family pathology and men reported more community problems and health concerns. Men drank significantly more than women, were more likely to have had a problem with alcohol over the past year, and were more likely to have been treated for substance abuse. For both men and women, the level of alcohol consumption varied directly with the severity of psychophysiological symptoms and community and health problems.

Adolescent↗
PubMed1995

Life events and miscarriage.

BACKGROUND: The aetiology of miscarriage is poorly understood. The aim of this study is to determine whether women admitted to hospital with miscarriage have experienced more psychosocial stress in early pregnancy than women whose pregnancies progress to labour. METHOD: Interviews of 48 case-control pairs, matched for known predictors of miscarriage risk, using the Life Events and Difficulties Schedule. RESULTS: The miscarriage group were more likely to have experienced a "severe life event" in the three months preceding miscarriage (35% v. 15%; P < 005); more likely to have been experiencing a "major social difficulty" (31% v. 4%; P < 0.002); and more likely to have experienced "life events of severe short-term threat" in the fortnight immediately beforehand (31% v. 4%; P < 0.002). Fifty-four per cent of the miscarriage group had experienced at least one of the above indicators of psychosocial stress before miscarrying, compared with 15% of controls (P = 0.0001). Other factors significantly associated with miscarriage included childhood maternal separation; non-UK European origin; poorer reported relationships with partners, and fewer social contacts. CONCLUSION. Psychosocial stress may be a factor in the aetiology of miscarriage. Alternatively, there may be a common determinant (e.g. personality, lifestyle or environmental) predisposing to both stress and miscarriage.

Abortion, Spontaneous↗
PubMed1993

Insulin receptor autophosphorylation occurs asymmetrically.

The unoccupied insulin receptor is a structurally symmetric, disulfide-linked dimer, comprising two alpha beta halves, each with a potential insulin binding alpha subunit and a kinase active beta subunit. In the accompanying paper (Shoelson, S. E., Lee, J., Lynch, C. S., Backer, J. M., and Pilch, P. F. (1993) J. Biol. Chem. 268, 4085-4091), we described the utility of a novel insulin analogue, L-benzoylphenylalanineB25,B29 epsilon-biotin insulin (BBpa insulin)1 as a probe for receptor behavior, and we determined that binding and cross-linking of one BBpa insulin molecule could fully stimulate insulin receptor autophosphorylation. Here we use this analogue to determine the symmetry of the autophosphorylation reaction. The alpha beta half-receptor that does not covalently couple to BBpa insulin incorporates 50% more orthophosphate than the alpha beta half that becomes coupled to the insulin analogue. Phosphopeptide mapping of each receptor half shows minimal differences in the phosphorylation sites or their relative contribution to the phosphate content of each half. The kinetics of 32P incorporation into each receptor half are essentially identical over a 10-20-min time course. Phosphopeptide mapping analysis reveals that the phosphate incorporation patterns do not change between the two alpha beta half-receptor forms (BBpa insulin-linked and unlinked, respectively) at different time points or concentrations of ATP ranging from 12 to 200 microM. Based on these and other data, we propose a model of insulin receptor activation whereby binding of one insulin molecule can trigger autophosphorylation in an asymmetric fashion.

3T3 Cells↗
PubMed1993

Increases in serum prolactin levels associated with syncopal attacks.

Numerous investigators have found that serum prolactin levels increase after tonic-clonic and partial complex seizures, but the effect of syncope on prolactin levels has been studied little. Serum prolactin levels were measured following unexpected syncopal attacks in patients seeking emergency treatment in a community hospital. Levels sampled 18 to 60 minutes after syncopal episodes were increased in 8 of 11 cases. Follow-up prolactin levels, measured 17 to 222 days later, were normal in all eight cases in which they were initially increased. Most subjects had concurrent illness. Although the current study does not clarify whether it was the syncope, the concurrent illness, or both that caused the prolactin elevations, it implies that measurement of this hormone will not help the clinician in distinguishing between seizures and syncopal attacks.

Adolescent↗
PubMed1991

Interfacial catalysis by phospholipase A2: evaluation of the interfacial rate constants by steady-state isotope effect studies.

The kinetics of hydrolysis of phospholipid vesicles by phospholipase A2 (PLA2) in the scooting mode can be described by the Michaelis-Menten formalism for the action of the enzyme in the interface (E*). E* + S in equilibrium E*S in equilibrium E*P in equilibrium E* + Products The values of the interfacial rate constants cannot be obtained by classical methods because the concentration of the substrate within the lipid bilayer is not easily manipulated. In the present study, carbonyl-carbon heavy atom isotope effects for the hydrolysis of phospholipids have been measured in both vesicles and in mixed micelles in which the phospholipid was present in the nonionic detergent Triton X-100. A large [14C]carbonyl carbon isotope effect of 1.12 +/- 0.02 was measured for the cobra venom PLA2-catalyzed hydrolysis of dipalmitoylphosphatidylcholine in Triton X-100. In contrast, no isotope effect (1.01 +/- 0.01) was measured for the action of the porcine pancreatic and cobra venom enzymes on vesicles of dimyristoylphosphatidylmethanol in the scooting mode. In a second experiment, the hydrolysis of vesicles was carried out in oxygen-18 enriched water. Analysis of the released fatty acid product by mass spectrometry showed that it contained only a single oxygen-18. All of these results were used to estimate both the forward and reverse commitments to catalysis. The lack of doubly labeled fatty acid demonstrated that the product is released from the E*P complex faster than the reverse of the esterolysis step. The small isotope effect in vesicles demonstrated that the E*S complex goes on to products faster than substrate is released from the enzyme. The relevance of these results to an understanding of substrate specificity and inhibition of PLA2 is discussed. In addition, the conditions placed on the values of the rate constants obtained in the present study together with results obtained in the other studies described in this series of papers have led to the evaluation of most of the interfacial rate constants for the hydrolysis of phospholipid vesicles by PLA2.

Animals↗
PubMed1991

Reliability of self-reports of alcohol use by community clients.

Eighty-five of 116 randomly selected clients receiving case management services at a comprehensive community mental health center responded anonymously to a survey questionnaire that included two measures of self-reported alcohol use: questions about frequency and quantity and a retrospective diary for reporting the number of drinks consumed daily in the preceding week. Forty-two patients reported using alcohol; consumption was higher among younger patients. A significant correlation was found between responses to the frequency-quantity questions and the information provided in the retrospective diary, indicating that self-reports of alcohol consumption are reasonably reliable for the clients studied. Future research is needed to establish the reliability and validity of self-reported alcohol and drug use in typical treatment settings.

Affective Disorders, Psychotic↗