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Biomedical subjects

K O'Connor

Publications and source records attributed to K O'Connor.

At least 37 records · Page 2Linked to original sources
PubMed1998

Influence of formulation variables on the morphology of biodegradable microparticles prepared by spray drying.

The preparation of microparticles of the biodegradable poly-DL-lactide (PLA) and polylactide-co-glycolide (PLGA) polymers using spray-drying technology was studied. Formulation parameters investigated include polymer type, polymer molecular weight, polymer concentration, and viscosity. Microparticles were characterized using electron microscopy, particle size analysis, and gel permeation chromatography. Kinematic viscosity was determined for each of the sprayed polymer solutions. Polymer molecular weight and polymer concentration were found to be important parameters when preparing PLA and PLGA microparticles using spray-drying technology.

Biocompatible Materials↗
PubMed1997

A 2-year study of sertraline in the treatment of obsessive-compulsive disorder.

The present study investigated the tolerability, safety profile, and anti-obsessional efficacy of sertraline, a selective serotonin reuptake inhibitor, during long-term treatment of patients with obsessive-compulsive disorder (OCD). Fifty-nine OCD patients who had completed a 1 year double-blind, fixed dose study comparing sertraline and placebo subsequently entered a 1-year open extension. Among the 51 patients who had been treated with sertraline during the double-blind phase, the mean total duration of sertraline treatment was 690 days. Only treatment responders who completed the 52-week double-blind treatment phase were permitted to enter the open extension. The higher rate (p < 0.02) of sertraline patients (51 out of 241) than of placebo patients (eight out of 84), who responded to treatment and entered the open-label phase is therefore consistent with the greater mean improvement observed in the sertraline group during double-blind treatment. Placebo responders differed from sertraline responders in that they were less impaired at baseline of the double-blind study [Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) of 18.5 versus 23.4] and they exhibited less improvement during double-blind treatment (-6.1 versus -11.4). In the open-label phase all patients received sertraline at a starting dose of 50 mg once a day, titrated in 50 mg increments to a maximum dose of 200 mg according to clinical response. At end-point the mean Y-BOCS score for all patients decreased by a further 3.6 points. Patients previously treated with placebo showed greater improvement after being switched to sertraline than those who received continued sertraline treatment. Patients who completed the study and received 2 full years of sertraline treatment (n = 38) exhibited a mean improvement of 15.6 points using the Y-BOCS. Sertraline was well tolerated during both the double-blind phase and the open extension, and the incidence of adverse experiences was generally reduced during the second year of treatment. Three patients discontinued open treatment because of adverse experiences. Long-term sertraline treatment did not appear to be associated with the emergence, increased incidence, or increased severity of adverse experiences or clinically significant abnormalities in laboratory tests, vital signs, or the electrocardiogram. The study supports the long-term safety and tolerability of sertraline over a 2-year treatment course and the sustained efficacy of sertraline in patients with OCD.

1-Naphthylamine↗
PubMed1997

An STS-based radiation hybrid map of the human genome.

We have constructed a physical map of the human genome by using a panel of 83 whole genome radiation hybrids (the Stanford G3 panel) in conjunction with 10,478 sequence-tagged sites (STSs) derived from random genomic DNA sequences, previously mapped genetic markers, and expressed sequences. Of these STSs, 5049 are framework markers that fall into 1766 high-confidence bins. An additional 945 STSs are indistinguishable in their map location from one or more of the framework markers. These 5994 mapped STSs have an average spacing of 500 kb. An additional 4484 STSs are positioned with respect to the framework markers. Comparison of the orders of markers on this map with orders derived from independent meiotic and YAC STS-content maps indicates that the error rate in defining high-confidence bins is < 5%. Analysis of 322 random cDNAs indicates that the map covers the vast majority of the human genome. This STS-based radiation hybrid map of the human genome brings us one step closer to the goal of a physical map containing 30,000 unique ordered landmarks with an average marker spacing of 100 kb.

Animals↗
PubMed1997

Dose escalation of paclitaxel with high-dose carboplatin using peripheral blood progenitor cell support in patients with advanced ovarian cancer.

A phase I study of escalating doses of paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) given in combination with high-dose carboplatin was conducted to identify the antitumor efficacy and maximum tolerated dose of paclitaxel in patients who had received sequential cycles of paclitaxel/cyclophosphamide as prior treatment for ovarian carcinoma. Eighteen patients with advanced ovarian cancer were treated in this study. Induction therapy consisted of two cycles of cyclophosphamide 3.0 g/m2 plus high-dose paclitaxel 300 mg/m2 plus filgrastim and leukapheresis to harvest peripheral blood progenitor cells, followed by four courses of rapidly cycled high-dose carboplatin with planned dose escalation of paclitaxel (150, 200, 250, and 300 mg/m2) rescued with peripheral blood progenitor cells. The study was amended after accrual of 11 patients, and the remaining seven patients received a single cycle of induction therapy with paclitaxel/cyclophosphamide, followed by four courses of rapidly cycled high-dose carboplatin with planned dose escalation of paclitaxel through levels 200 and 250 mg/m2. All 18 patients have completed therapy. Of the 15 who are evaluable for response, the pathologic complete response was 33% (five of 15 patients). The administration of escalating doses of paclitaxel in combination with high-dose carboplatin following sequential cycles of paclitaxel/cyclophosphamide induction resulted in significant nonhematopoietic toxicity. Induction with a single cycle of paclitaxel/cyclophosphamide resulted in excellent progenitor cell mobilization, and significantly ameliorated the toxicity of this approach. The response rates thus far obtained are promising and warrant further evaluation.

Adult↗
PubMed1996

Dimensions of life meaning: a qualitative investigation at mid-life.

Meaning in life is integral to psychological functioning. Empirical research into this construct has focused on sources of meaning. Reker & Wong (1988) have proposed a theoretical outline for a multidimensional structure of meaning which challenges a source-based approach. The present study used a qualitative approach to explore people's accounts of their experiences of life meaning and focused on the following key dimensions: sources; cognitive, motivational and affective components; breadth; and depth. Thirty-eight adults at mid-life were interviewed in depth. Five categories of sources accounted for material reported in previous studies, but a sixth was required to contain experiences of meaning relating to the natural environment. All sources revealed cognitive, motivational and affective components. Accounts showed variation in breadth and depth of meaning, although the assessment of depth proved problematic. Results from this qualitative exploration generally confirm Reker & Wong's structural model. Furthermore, many people have coherent frameworks of meaning which structure their life experiences, and serve to integrate these theoretical dimensions.

Adult↗
PubMed1996

The effect of nutrient limitation on styrene metabolism in Pseudomonas putida CA-3.

Styrene degradation in Pseudomonas putida CA-3 has previously been shown to be subject to catabolite repression in batch culture. We report here on the catabolite-repressing effects of succinate and glutamate and the effects of a limiting inorganic-nutrient concentration on the styrene degradation pathway of P. putida CA-3 in a chemostat culture at low growth rates (0.05 h-1). Oxidation of styrene and the presence of styrene oxide isomerase and phenylacetaldehyde dehydrogenase activities were used as a measure of the expression of the styrene degradation pathway. Both glutamate and succinate failed to repress the styrene degradation ability under growth conditions of carbon and energy limitation. Lower levels of enzyme activities of the styrene degradation pathway were seen in cells grown on styrene or phenylacetic acid (PAA) under conditions of both ammonia and sulfate limitation than were seen under carbon and energy limitation. Cells grown on PAA under continuous culture oxidize styrene and styrene oxide and possess styrene oxide isomerase and NAD(+)-dependent phenylacetaldehyde dehydrogenase activities. Catabolite repression of styrene metabolism was observed in cells grown on styrene or PAA in the presence of growth-saturating (nonlimiting) concentrations of succinate or glutamate under sulfate limitation.

Aldehyde Oxidoreductases↗
PubMed1995

Muscle control in chronic tic disorders.

EMG was recorded in nine subjects suffering from chronic tic disorder. Six subjects suffered asymmetrical tics and three had symmetrical tics. EMG in tic-affected and contralateral nonaffected sites was recorded at rest, during a baseline period, and at postbiofeedback training. All subjects received 2-4 biofeedback training sessions aimed at enhancing their ability to control levels of muscle contraction in both affected and nonaffected sites. All nine subjects met the criterion of discriminating unaided between levels of 0, 25%, 50%, and 75% of their fullest contraction. Five of the six people with asymmetrical tics showed lower resting EMG on the affected side at baseline, but EMG significantly increased in tic-affected but not nonaffected muscles after exercises aimed at enhancing muscle control. Six subjects reported a clinically significant > or = 40% decrease in tic frequency. The reflexlike quality of tic muscles can modified by biofeedback training and this constitutes a useful and relatively quickly acquired aid to tic management.

Adult↗
PubMed1995

Inference processes in obsessive-compulsive disorder: some clinical observations.

In this paper we outline a cognitive model of Obsessive-Compulsive Disorder (OCD) which proposes that the core belief of OCD evolves through a series of illogical inferences. These faulty inference processes involve inferring the plausibility of events on the basis of irrelevant associations, dismissing actual evidence on the grounds of going beyond surface reality to a deeper reality, and finally inferring that a completely fictional narrative is a remote probability. A therapy aimed specifically at changing these inference processes is illustrated with case examples of OCD clients who had not benefited from conventional behavior therapy. The inference based approach (IBA) complements existing cognitive-behavioral therapy but suggests that in certain cases, the conventional cognitive therapy view of OCD beliefs as exaggerated fears of remote possibilities may actually reinforce the obsessional belief since even remote events are real. The IBA on the contrary suggests that an important goal in therapy is to highlight this confusion found in OCD between imagination and reality and illuminate for the OCD client how their compulsions, far from reassuring them about a remote possibility, actually take them further away from reality and reinforce their imaginary doubt.

Adult↗
PubMed1995

The effects of sulindac on colorectal proliferation and apoptosis in familial adenomatous polyposis.

BACKGROUND & AIMS: The mechanism by which sulindac causes regression of adenomas in patients with familial adenomatous polyposis (FAP) is unclear. Conflicting data on the drug's effects on colorectal epithelial proliferation have been reported. An alternative mechanism, and one not previously studied, is via induction of colorectal epithelial cell apoptosis (programmed cell death). This hypothesis was tested by studying the effects of sulindac on colorectal epithelial proliferation and apoptosis in patients with FAP. METHODS: Cell proliferation was studied via immunohistochemistry for cell nuclear antigen in a group of 22 patients randomized to either sulindac (150 mg twice a day) or placebo in a previously published trial. The rectal epithelium from 7 additional patients with FAP treated with sulindac was examined by flow cytometry to assess changes in cell-cycle distribution and apoptosis. RESULTS: Although sulindac caused a significant decrease in polyp size and number, there was no significant change in cytokinetic variables or cell cycle distribution 3 months after treatment. However, the subdiploid apoptotic fraction was increased significantly 3 months after treatment with sulindac (31.3% +/- 4.8% compared with 10% +/- 4.3% at baseline; P = 0.01). CONCLUSIONS: Our findings suggest that sulindac does not affect colorectal epithelial proliferation and that its effects in patients with FAP may instead result from induction of apoptosis.

Adenomatous Polyposis Coli↗
PubMed1995

Evaluation of four methods of warming intravenous fluids.

OBJECTIVE: The purpose of this in vitro study was to compare four methods of warming intravenous fluid (IVF) with a control of unwarmed IVF at flow rates of 200, 400, 600, 800, and 1000 ml/hr. DESIGN: A 5 x 5 factorial experimental design was used to evaluate the methods of warming IVF and the control at varied flow rates. METHODS: The methods of warming IVF in this study included the following: (1) the Level 1 System 250 fluid warmer with D-60HL tubing (Level 1 Technologies, Inc., Rockland, Mass.); (2) the Level 1 System 250 fluid warmer with D-50 tubing (Level 1 Technologies, Inc.); (3) the Hotline fluid warmer with L-70 tubing (Level 1 Technologies, Inc.); and (4) the Baxter DW 1000 D blood fluid warmer with blood cuff set tubing (Baxter Healthcare Corporation, Valencia, Calif.). The IVF temperatures were measured with thermocouples at three points: (1) in the intravenous solution bag, (2) in the tubing after the infusion pump, and (3) 2 cm proximal to the end of the tubing. Ambient temperature and the temperature at the three measurement points were recorded when the temperature at the point 2 cm proximal to the end of the tubing was stable for 3 minutes. RESULTS: With single-lumen tubing, fluids flowing at low rates (e.g., 200 ml/hr) were barely warm at the end of the tubing. In contrast, fluid warmed with triple-lumen technology was consistently kept warm throughout the tubing.

Clinical Nursing Research↗
PubMed1995

Possible regulatory role for nonaromatic carbon sources in styrene degradation by Pseudomonas putida CA-3.

Styrene metabolism in styrene-degrading Pseudomonas putida CA-3 cells has been shown to proceed via styrene oxide, phenylacetaldehyde, and phenylacetic acid. The initial step in styrene degradation by strain CA-3 is oxygen-dependent epoxidation of styrene to styrene oxide, which is subsequently isomerized to phenylacetaldehyde. Phenylacetaldehyde is then oxidized to phenylacetic acid. Styrene, styrene oxide, and phenylacetaldehyde induce the enzymes involved in the degradation of styrene to phenylacetic acid by P. putida CA-3. Phenylacetic acid-induced cells do not oxidize styrene or styrene oxide. Thus, styrene degradation by P. putida CA-3 can be subdivided further into an upper pathway which consists of styrene, styrene oxide, and phenylacetaldehyde and a lower pathway which begins with phenylacetic acid. Studies of the repression of styrene degradation by P. putida CA-3 show that glucose has no effect on the activity of styrene-degrading enzymes. However, both glutamate and citrate repress styrene degradation and phenylacetic acid degradation, showing a common control mechanism on upper pathway and lower pathway intermediates.

Aldehyde Oxidoreductases↗
PubMed1995

What the future holds for managed care. From legacy to new generation.

Legacies used to be legends--each one a proud heritage admired, respected, held in awe. Today they are mainframe, claims-based information system workhorses that cannot keep up with the promise of managed care. But for now, they might just be the best interim solution. The promises of future technologies for the managed care information age are still just promises, according to the experts. If you're thinking of replacing your legacy system, the experts say wait while the healthcare and technology markets try to figure out each other.

Capitation Fee↗
PubMed1995

Cell adhesion to biomaterials: correlations between surface charge, surface roughness, adsorbed protein, and cell morphology.

Adhesion of cells to a biomaterial surface can be a major factor mediating its biocompatibility. In this investigation, jet impingement techniques were used to quantify strength of cellular adhesion to various material surfaces. The metals tested: HS25 (a cobalt-based alloy similar to F75), 316L stainless steel, Ti-6Al-4V, and commercially pure tantalum, exhibited nearly a fivefold increase in adhesion strength above that characteristic of the polymeric materials tested (PTFE, silicone rubber, and HDPE). The present study examines physical and biological factors that might influence fibroblast adhesion to the biomaterial surface. The relation between surface charge and cellular adhesion was investigated in a controlled manner by measuring adhesion strength over a range of charge densities. The cells showed charge and electrical potential-dependent adhesion maxima, suggesting that surface alloying for optimum adherence may be possible. In a preliminary series of experiments adsorbed serum protein layers on a series of materials of differing adherence were investigated using gel electrophoresis to assess protein composition. Analysis of adsorbed proteins revealed little difference in relative abundance or total adsorption quantity. SEM micrographs of cells on Ti-6Al-4V and silicone rubber (high and low adhesion materials, respectively) demonstrated differences in cell morphology and cell density.

Biocompatible Materials↗
PubMed1994

The consumer revolution arrives. Using smart customer service to attract, educate, & retain satisfied members & lower costs.

Across the country, managed care organizations pursue ways to enhance customer service and maintain member satisfaction, without breaking the bank by authorizing unnecessary services. One method gaining popularity is reducing customer demand for inappropriate services through education. Approaches include welcome-to-the-plan calls, member education, automated and in-person answer lines, and 24-hour telephone coverage. Several firms have recognized the need for such services, and offer them to HMOs on an outsourcing basis, with generally positive results.

Consumer Behavior↗
PubMed1994

The consumer revolution arrives. Using smart customer service to attract, educate & retain satisfied members & lower costs.

Across the country, managed care organizations pursue ways to enhance customer service and maintain member satisfaction, without breaking the bank by authorizing unnecessary services. One method gaining popularity is reducing customer demand for inappropriate services through education. Approaches include welcome-to-the-plan calls, member education, automated and in-person answer lines, and 24-hour telephone coverage. Several firms have recognized the need for such services, and offer them to HMOs on an outsourcing basis, with generally positive results.

Communication↗
PubMed1994

Influence of affective words on lexical decision task in major depression.

In cognitive science, lexical decision task is used to investigate visual word recognition and lexical access. The issue of whether or not individuals who are depressed differ in their access to affectively laden words and specifically to words that have negative affect was examined. Based on some aspects of the Resource Allocation Model (Ellis), it was postulated that patients suffering from depression take more time to recognize items from an affective-loaded list. In order to compare their behavior in a lexical decision task, patients suffering from depression and healthy controls were studied. We hoped to find an interaction between the mood state of subjects and the categories (affective or neutral) of words. Two groups of right-handed adults served as subjects in our experiment. The first group consisted of 11 patients suffering from depression (mean age: 40.2; sd: 6.8). All of this group met the DSM-III-R and the Research Diagnostic Criteria for major depressive disorder. Severity of their disease was rated using the 24-item Hamilton Depressive Rating Scale. All patients suffering from depression were without psychotropic medication. The control group was composed of 24 subjects (mean age: 32.7; sd: 7.9). A depressive word-list and a neutral word-list were built and a computer was used for the lexical-decision task. A longer reaction time to detect the non-word stimuli (F1,33 = 11.19, p < 0.01) was observed with the patients by comparison to the normal subjects. In the analysis of the word stimuli, a group by list interaction (F1,33 = 7.18, p < 0.01) was found.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗