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Biomedical subjects

C O'Hara

Publications and source records attributed to C O'Hara.

At least 19 recordsLinked to original sources
PubMed2000

Expression pattern of T-cell-associated chemokine receptors and their chemokines correlates with specific subtypes of T-cell non-Hodgkin lymphoma.

Chemokine receptors mediate the migration of lymphocytes through the binding of soluble ligands, and their expression is differentially regulated in lymphocyte subsets. The pattern of chemokine receptor expression in T-cell non-Hodgkin lymphoma has not been previously studied. Using a panel of mouse monoclonal antibodies, we studied the immunohistochemical expression of the Th1-associated chemokine receptor CXCR3 in 141 patients with T-cell lymphoma, and we studied the receptors CCR4 and CCR5 and some of their ligands in a subset of these tumors. Expression of CXCR3 was typical of the smaller T cells in angioimmunoblastic lymphoma (15 of 18 patients), angiocentric lymphoma (3 of 3 patients), histiocyte-rich tumors (4 of 5 patients), and unspecified T-cell lymphomas (17 of 39 patients). CXCR3 expression was seen in only 1 of 15 patients with anaplastic lymphoma kinase (ALK)-positive anaplastic large-cell lymphoma. In contrast, all ALK-positive tumors showed diffuse reactivity for the Th2-associated receptor CCR4 (5 of 5 patients). CCR4 expression was also a consistent feature of the large-cell transformation of mycosis fungoides. CCR5 expression showed no consistent association with any T-cell tumor type. The chemokines Mig (CXCR3 ligand), TARC (CCR4 ligand), and MCP-2 (CCR5 ligand) were detected in intratumoral blood vessels and histiocytes. Mig was also coexpressed by a subset of CXCR3-positive tumor cells in 6 of 20 lymphomas. MCP-2 was highly expressed in stromal cells in 3 patients with nodal involvement by cutaneous T-cell lymphoma. As with normal T-cell subsets, we demonstrated that there is frequent differential expression of chemokine receptors in T-cell tumors, which may explain, in part, the distinctive patterns of spread in different tumor subtypes. (Blood. 2000;96:685-690)

Anaplastic Lymphoma Kinase↗
PubMed2000

Effects of seasonal allergic rhinitis on selected cognitive abilities.

BACKGROUND: Many allergy patients complain of slowed thinking, memory problems, and difficulty sustaining attention during their allergy seasons. OBJECTIVE: This study evaluated the effect of symptomatic allergic rhinitis on speed of cognitive processing, ability to divide and sustain attention, working memory, and recent verbal memory. METHODS: Symptomatic ragweed-allergic rhinitis patients and nonatopic control subjects did cognitive testing in, out of, and in ragweed seasons. RESULTS: Test results indicate that, during ragweed seasons, allergic patients experience subtle slowed speed of cognitive processing but not deficits in attention and recent memory. Some patients also have difficulties in working memory. CONCLUSIONS: These findings suggest that having allergic reactions to ragweed pollen causes significant cognitive difficulties in a subgroup of patients.

Adult↗
PubMed1999

Chemotherapy with etoposide, vincristine, doxorubicin, bolus cyclophosphamide, and oral prednisone in patients with refractory cutaneous T-cell lymphoma.

BACKGROUND: This Phase II study was undertaken to assess the efficacy and toxicity of chemotherapy with etoposide, vincristine, doxorubicin, bolus cyclophosphamide, and oral prednisone (EPOCH regimen) in patients with advanced, refractory cutaneous T-cell lymphoma (CTCL). METHODS: Fifteen patients were treated with a 96-hour continuous infusion of etoposide, vincristine, doxorubicin, bolus cyclophosphamide, and oral prednisone, followed by granulocyte-colony stimulating factor support and trimethoprim/sulfamethoxazole prophylaxis. The median age of the patients was 53 years (range, 17-82 years). Six patients had Sézary syndrome (SS), four patients had visceral involvement, and four patients had anaplastic large cell morphology, three with Ki-1 (CD30) positivity. All patients had disease that was refractory to prior chemotherapy or electron beam irradiation and eight of these patients had received cyclophosphamide, doxorubicin, vincristine, and prednisone. Seven patients had received prior interferon therapy and nine patients had received fludarabine and/or 2-CDA. RESULTS: After a median of 5 cycles (range, 1-9 cycles), 4 patients achieved a complete response (27%) and 8 patients achieved a partial response (53%) for an overall response rate of 80% (95% confidence interval, 52-96%). Three patients with visceral involvement, two of three patients with anaplastic large cell morphology, and one patient with human T-cell lymphoma virus leukemia/lymphoma did not respond. All 12 responders had improvement in skin disease; 2 of 6 patients with SS had complete disappearance of circulating Sézary cells. The median progression free survival was 8.0 months (range, 3-22 months). After a median follow-up of 11.4 months (range, 2-56+ months), the median patient survival was 13.5 months. Grade 3 or 4 hematologic toxicity occurred in 8 patients (61%); 5 of these 8 patients had febrile neutropenia. Six patients developed staphylococcal bacteremia, two patients had disseminated herpes infection, and one patient had Pneumocystis carinii pneumonia. Grade 3 neurotoxicity occurred in one patient. Two patients had a significant decrease in left ventricular ejection fraction and one patient had supraventricular tachycardia. CONCLUSIONS: EPOCH chemotherapy has a high response rate with acceptable toxicity in patients with advanced and refractory CTCL.

Administration, Oral↗
PubMed1998

Fluorescence in situ hybridization to assess aneuploidy for chromosomes 7 and 8 in hematologic disorders.

Stored, fixed cell suspensions of bone marrows from 70 patients karyotyped over a three-year period for myelodysplastic syndrome (MDS) or related hematologic conditions were retrospectively studied in two series using centromeric probes for chromosomes 7 and 8. Series I consisted of patient samples with numerical and/or structural abnormalities of chromosomes 7 or 8, matched with chromosomally normal samples from about the same time period. Series II consisted of consecutive MDS patient samples as well as patient samples in which one or more cells had numerical or structural abnormalities of 7 and 8. In both series, probes for chromosomes 7 and 8 were applied in each case and at least 100 nuclei were scored for each probe for the distribution of one, two, or three signals. Twenty-seven cases had clonal abnormalities by routine cytogenetics (RC): 12 with monosomy 7; one with monosomy 8; five with trisomy 8; nine with clonal abnormalities other than 7 or 8 aneuploidy. Eleven cytogenetically normal cases gave abnormal interphase FISH (IF) results; one was subsequently confirmed by metaphase FISH analysis to have a clonal structural abnormality of chromosome 7; one case with a trisomy 8 clone, in remission by RC, showed 35% of cells by IF with three signals for chromosome 8; one case had heteromorphic chromosomes by FISH. Of eight remaining cases, five (four with -7 and one with +8 by IF) were among 22 cases of cytogenetically normal MDS. Three remaining cases (two with +8 and one with both +7 and +8 by IF) had AML or MPD. The high rate of possible undetected monosomy 7, among MDS cases in particular, suggests all MDS cases should be screened by IF.

Aneuploidy↗
PubMed1997

An outbreak of Enterobacter hormaechei infection and colonization in an intensive care nursery.

Enterobacter hormaechei was first identified as a unique species in 1989. Between 29 November 1992 and 17 March 1993, an outbreak of E. hormaechei occurred among premature infants in the intensive care nursery (ICN) at The Hospital of the University of Pennsylvania. The 10 infants whose cultures were positive for E. hormaechei (six were infected and four were colonized) had a lower median estimated gestational age and birth weight than did other ICN infants; other risk factors for infection or colonization with E. hormaechei were not identified. Cultures from three isolettes and a doorknob in the ICN were positive for E. hormaechei. Pulsed-field gel electrophoresis of isolates from six patients and two isolettes were identical. Observations of health care workers revealed breaks in infection control techniques that may have allowed transmission of this organism. We found that E. hormaechei is a nosocomial pathogen that can infect vulnerable hospitalized patients and that can be transmitted from patient to patient when infection control techniques are inadequate.

Disease Outbreaks↗
PubMed1996

HIV-1 Langerhans' cell tropism associated with heterosexual transmission of HIV.

Heterosexual transmission by vaginal intercourse accounts for most transmission of human immunodeficiency virus-type 1 (HIV-1) in Africa and Asia but is less important in the HIV-1 epidemics of the United States and Western Europe. Epithelial Langerhans' cells (LCs) represent a possible source of initial cell contact for vaginal infection. Fifteen primary isolates of HIV-1 from U.S. homosexuals and 18 HIV-1 isolates from Thailand heterosexuals were evaluated for growth in LCs of U.S. origin. All the viruses from the Thai heterosexuals, which were subtype E, grew more efficiently in the LCs than any of the viruses from the U.S. homosexuals, which are subtype B. These results suggest that LC tropism is associated with the efficiency of heterosexual transmission of HIV.

Cell Line↗
PubMed1995

Benchmarking critical pathways--a method for achieving best practice.

This article outlines the processes for the development and implementation of critical pathways to achieve best practice by two health organisations funded under the Commonwealth Government's Best Practice in the Health Sector Program. Each organisation is using a slightly different approach to using benchmarking as a tool to ensure best practice is achieved, however, they are similar in that they each demonstrate customer focus and a multidisciplinary, participative change management style.

Australia↗
PubMed1994

Posttraumatic narcolepsy in mild to moderate closed head injury.

Scattered reports exist describing secondary narcolepsy that develops following disease or organic insult to the brain. The present study is concerned with one particular type of secondary narcolepsy, posttraumatic narcolepsy, which we define as "narcolepsy that develops following a head injury in a previously asymptomatic individual". We obtained data on nine patients who had been previously diagnosed with mild to moderate closed head injury and who had unresolved sleep complaints. All patients presented with complaints of excessive daytime somnolence and/or sleep attacks. Patients also presented with a mix of cataplexy, hypnagogic hallucinations and/or sleep paralysis. All patients had undergone previous neurological and/or neuropsychological evaluation and testing, with seven of the nine patients having the Halstead-Reitan Neuropsychological Test Battery. Human leucocyte antigen (HLA) tissue typing was obtained in six of the nine cases. The standard protocol was utilized, consisting of overnight polysomnography with a Multiple Sleep Latency Test (MSLT) the following day. All patients' histories were negative for narcolepsy or any other significant sleep disorders prior to the head injury. The results of the neuropsychological testing indicated that all patients fell within the mild to moderate impairment range. The results of overnight polysomnography and MSLT data, along with patient histories, indicated a diagnosis of narcolepsy in all cases. The results of HLA typing indicated that three patients were DR2 positive, two were DR4 positive and one was DQW1 positive. We conclude that narcolepsy may be "dormant" and that, in cases genetically at risk, even a minor injury to the central nervous system can cause that person to become symptomatic.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Neoadjuvant treatment of stage IIIA non-small cell lung cancer. Long-term results.

The multimodality approach to locally advanced Stage III non-small cell lung cancer is continuing to evolve. In this trial, 54 patients with surgically staged IIIA disease were treated with neoadjuvant chemotherapy, surgical resection, and chest radiotherapy. Response to four cycles of CAP chemotherapy (cyclophosphamide, doxorubicin, cisplatin) was 39% (8% complete responses). One septic death occurred. Thoracotomy was performed on 31 patients, of whom 29 (56%) were resected and 24 (44%) were completely resected. Complete resections were more frequently observed in chemotherapy responders. Extranodal mediastinal extension in nonresponding patients was the most frequent reason not to attempt thoracotomy. The overall median times to progression and survival were 11.6 (.7-66.5) and 17.9 (2.8-71.4) months. Long-term disease-free survival was observed in 11 patients (20%) with a median follow-up of 46.5 (24-71) months. All these patients underwent complete resection and constitute 46% of the patients undergoing complete resection. Median times to progression and survival were 33.4 (5.0-66.5) and 33.5 (10-71.4) months for completely resected patients. Although the ability to perform surgery identified a population that has favorable locoregional control and disease-free survival, distant relapse continues to represent the major obstacle to enhanced survival in resected patients. Unresected patients, however, are likely to relapse in both local and distant sites. Response to chemotherapy may not only enhance systemic control, but may also increase the probability of complete resection. Randomized trials should be conducted to evaluate the role of individual modalities (surgery, chemotherapy, or radiotherapy) while applying the remaining modalities maximally. The temptation to compare different treatment approaches should be resisted.

Adult↗
PubMed1992

Tumor selective reactivity of a monoclonal antibody prepared against a recombinant peptide derived from the DF3 human breast carcinoma-associated antigen.

The DF3 antigen is a member of a family of high molecular weight glycoproteins aberrantly expressed in malignant mammary epithelium. We have generated a monoclonal antibody (MAb), designated DF3-P, against a recombinant DF3/beta-galactosidase fusion protein. Characterization of this MAb has demonstrated reactivity with immature precursors of DF3 antigen and not with the secreted form. These findings are in contrast to those obtained with MAb DF3, a previously described antibody with predominant reactivity against the mature glycoprotein. The finding that deglycosylation of secreted DF3 antigen with neuraminidase and endo-alpha-N-acetylgalactosaminidase is associated with increased MAb DF3-P reactivity provided additional support for the selectivity of this antibody against the protein core. Epitope mapping studies demonstrate that both the DF3-P and DF3 epitopes are located at a TRPAPGS domain in the 20-amino acid tandem repeat. The results of competition studies with synthetic peptides indicate that the proline in this domain is involved in both epitopes, while the potential glycosylation sites at threonine and serine may contribute to the differential reactivity of MAbs DF3 and DF3-P. Taken together, these findings suggest that both antibodies react with a similar epitope that is modified by the presence of carbohydrate moieties. The results of immunoperoxidase staining studies further demonstrate that while MAb DF3-P reacts with formalin-fixed sections of breast carcinomas, this antibody exhibits little if any reactivity with normal mammary epithelium. Selective expression of the DF3-P epitope in malignant breast cells may be useful in identifying this transformed phenotype.

Animals↗
PubMed1992

In vitro activities of streptomycin and 11 oral antimicrobial agents against clinical isolates of Klebsiella rhinoscleromatis.

We tested in vitro the activities of streptomycin and tetracycline--antibiotics that have long been used to treat rhinoscleroma--as well as several newer oral agents by using 23 isolates of the causative organism Klebsiella rhinoscleromatis. All isolates were inhibited by clinically achievable concentrations of trimethoprim-sulfamethoxazole, amoxicillin-clavulanate, chloramphenicol, ciprofloxacin, cephalexin, cefuroxime, and cefpodoxime.

Anti-Bacterial Agents↗
PubMed1991

Induction of hemoglobin synthesis by downregulation of MYB protein with an antisense oligodeoxynucleotide.

Reduced expression of the proto-oncogene c-myb appears necessary for erythroid differentiation induced by chemical agents and by the natural regulator, erythropoietin (Epo). Treatment of Epo-responsive Rauscher erythroleukemia cells with an anti-sense oligodeoxynucleotide to c-myb in the absence of other inducers downregulated myb protein markedly and caused hemoglobinization of the cells within 48 hours. Epo treatment, which downregulates c-myb in these cells, induced hemoglobinization to the same degree. Epo also induced the appearance of anion transport protein on the plasma membrane, consistent with terminal differentiation. In contrast, antisense c-myb did not induce this erythroid marker. The results are consistent with a role for myb protein in the regulation of hemoglobin synthesis.

Animals↗
PubMed1991

Tumor necrosis factor expression by human ovarian carcinoma in vivo.

Tumor necrosis factor (TNF) is a cytokine produced by monocytes and other cells with selective cytolytic activity against some but not all tumor cells. Cellular resistance to the cytolytic effects of TNF has been reported to be associated with autocrine production of TNF by the target cells. The purpose of this study was to determine whether or not human tumors produce tumor necrosis factor in vivo. Ovarian carcinoma tissue from 25 patients with ovarian carcinoma was examined for the presence of TNF. Four of 5 ascites fluid specimens and tissue sections of 16 of 20 patients were positive for TNF by immunoperoxidase staining. The source of the immunoreactive protein was further examined by in situ hybridization studies. TNF mRNA was detectable in each of the ascites specimens and 7 of 16 tissue sections that were positive by immunoperoxidase staining. These findings suggest that TNF is produced by some human tumors in vivo and that the association between TNF production and resistance to TNF antitumor action may be clinically relevant.

Ascites↗
PubMed1991

Flow cytometric measurement of cell cycle kinetics in rat Walker-256 carcinoma following in vivo and in vitro pulse labelling with bromodeoxyuridine.

Flow cytometric measurements of total DNA content, cell cycle distribution, and bromodeoxyuridine (BrdUrd) uptake were made in rat Walker-256 carcinoma cells. After both in vivo and in vitro pulse labelling with BrdUrd, Walker-256 tumor cells were stained with propidium iodide (PI) to estimate the total DNA content and a monoclonal antibody against BrdUrd to estimate the relative amount of cells in S phase. BrdUrd-labelled single cell suspensions were harvested at different time intervals to determine the movement of these cells within the cell cycle. To increase BrdUrd uptake, fluorodeoxyuridine (FDU), a thymidine antagonist, was also applied in vivo and in vitro. The results indicated exponential growth characteristics for this tumor between days 5 and 8 after implantation. Tumor doubling times, derived from changes in tumor volume in vivo and from the increase in cell number in vitro were similar. The mean time for DNA synthesis was estimated from the relative movement of BrdUrd-labelled cells towards G2. The percent of cells labelled with BrdUrd and the DNA synthesis time were similar regardless of the mode of BrdUrd administration. This study demonstrates that BrdUrd labelling of rat Walker-256 carcinoma cells in vitro yields kinetic estimates of tumor proliferation during exponential growth similar to those with the administration of BrdUrd in the intact tumor-bearing rat.

Animals↗
PubMed1991

Well-differentiated hepatocellular carcinoma associated with long-term survival. Report of two cases.

Two cases of well-differentiated hepatocellular carcinoma (HCC) with focal biliary differentiation are presented. The distinct histological features of these neoplasms and the unusually protracted clinical course of 8 and 10 years distinguish them from previously described pathological categories of primary hepatic tumors. Electron microscopic and immunohistochemical findings support a dual hepatic and bile duct differentiation of the tumor cells. If additional examples of this tumor are found to be associated with a similarly prolonged symptom-free survival, the distinction of this entity from traditional, rapidly fatal HCC becomes important. Less aggressive therapeutic options may be entertained.

Adult↗
PubMed1991

Comparison of the autoSCAN-W/A rapid bacterial identification system and the Vitek AutoMicrobic system for identification of gram-negative bacilli.

The autoSCAN-W/A (W/A; Baxter MicroScan, West Sacramento, Calif.) with the new fluorometric Rapid Neg Combo 1 (RNC) panel is a fully automated fluorometric system for identification of both enteric and nonenteric gram-negative bacilli within 2 h. We compared the W/A with the Vitek AutoMicrobic System (Vitek AMS; Vitek Systems, Inc., Hazelwood, Mo.) for identification of 383 clinical isolates of gram-negative bacilli. The API 20E (Analytab Products, Plainview, N.Y.) and conventional biochemical testing were used as the reference systems. The W/A correctly identified 336 isolates (87.7%) to the species level and classified an additional 29 isolates (7.6%) as correct with low probability (overall identification = 95.3%); the Vitek AMS correctly identified 355 isolates (92.7%) to the species level and classified an additional 8 isolates (2.1%) as correct with low probability (overall identification = 94.8%). A common set of 134 isolates of gram-negative bacilli was tested in both participating laboratories as a means of assessing interlaboratory agreement with both the W/A and the Vitek AMS. The overall agreements between the two laboratories were 86% with the W/A and 92% with the Vitek AMS. The W/A performed comparably to the Vitek AMS for identification of most gram-negative bacilli, actually exceeding the Vitek AMS for identification of nonenteric bacilli. Rapid time to identification and a high level of automation make the W/A an attractive system for clinical microbiology laboratories.

Bacteriological Techniques↗
PubMed1990

Response patterns of hairy cell leukemia to B-cell mitogens and growth factors.

The effect of mitogens and/or recombinant B-cell growth factors (M/GFs) on the in vitro growth of hairy cells was examined. Tumor cells were isolated from the spleens of four patients with hairy cell leukemia (HCL) by Ficoll-Hypaque sedimentation and E-rosetting. Enrichment for tumor cells was confirmed with intracytoplasmic immunoglobulin (Ig) staining, tartrate resistant acid phosphatase (TRAP) staining, and staining using monoclonal antibodies (MoAbs) directed at B, T, myeloid, and monocytoid antigens (Ags) in indirect immunofluorescence assays. Tumor cells were B1(CD20)+ B2(CD21)- B4(CD19)+ IL-2R(CD25)+ PCA-1 +/- TRAP+. HCLs neither synthesized DNA nor secreted Ig in response to culture with granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-1 alpha (IL-1 alpha), IL-1 beta, IL-2, IL-3, IL-4, IL-5, or IL-6. However, a proliferative response (stimulation index greater than or equal to 3.0) without Ig secretion was triggered in HCLs by mitogens or combinations of GFs. Specifically, DNA synthesis was induced at 3 days in three of four HCL samples cultured with Staphylococcus aureus Cowan A (SAC) or the combination of phorbol ester (TPA) and the calcium ionophore A 23187 (Ca2+); DNA synthesis was triggered later (day 7) by tumor necrosis factor (TNF) or by IL-4 and IL-5. In contrast, the fourth patient, a nonresponder to SAC or TPA/Ca2+, demonstrated increased DNA synthesis at day 3 when cocultured with IL-4 and IL-5. Both autoradiography and staining with antibromodeoxyuridine (BrdU) MoAb conjugated to fluorescein confirmed DNA synthesis by only a minority (5% to 23%) of tumor cells within each patient. Dual staining confirmed that responsive cells were both BrdU+ and TRAP+. DNA synthesis induced by TPA/Ca2+ was blocked specifically by anti-IL-6 Ab; in contrast, the HCL proliferative response to SAC, TNF, or IL-4 and IL-5 was not inhibited by anti-IL-6 Ab. alpha-Interferon inhibited the response to TPA/Ca2+, TNF, or IL-4 and IL-5 without any effect on response to SAC. Finally, peroxidase-antiperoxidase staining demonstrated that HCLs are induced by TPA/Ca2+, but not by SAC, to produce intracytoplasmic IL-6. These data demonstrate IL-4, IL-5, and IL-6 mediated DNA synthesis by HCLs in vitro and suggest a possible in vivo role for these growth factors in the pathophysiology of HCL.

B-Lymphocytes↗