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Biomedical subjects

D O'Malley

Publications and source records attributed to D O'Malley.

At least 19 recordsLinked to original sources
PubMed2005

The neurotransmitters glycine and GABA stimulate glucagon-like peptide-1 release from the GLUTag cell line.

The incretin hormone, glucagon-like peptide-1 (GLP-1) is released from intestinal L-cells following food ingestion. Its secretion is triggered by a range of nutrients, including fats, carbohydrates and proteins. We reported previously that Na(+)-dependent glutamine uptake triggered electrical activity and GLP-1 release from the L-cell model line GLUTag. However, whereas alanine also triggered membrane depolarization and GLP-1 secretion, the response was Na+ independent. A range of alanine analogues, including d-alanine, beta-alanine, glycine and l-serine, but not d-serine, triggered similar depolarizing currents and elevation of intracellular [Ca2+], a sensitivity profile suggesting the involvement of glycine receptors. In support of this idea, glycine-induced currents and GLP-1 release were blocked by strychnine, and currents showed a 58.5 mV shift in reversal potential per 10-fold change in [Cl-], consistent with the activation of a Cl(-)-selective current. GABA, an agonist of related Cl- channels, also triggered Cl- currents and secretion, which were sensitive to picrotoxin. GABA-triggered [Ca2+]i increments were abolished by bicuculline and partially impaired by (1,2,5,6-tetrahydropyridine-4-yl)methylphosphinic acid (TPMPA), suggesting the involvement of both GABA(A) and GABA(C) receptors. Expression of GABA(A), GABA(C) and glycine receptor subunits was confirmed by RT-PCR. Glycine-triggered GLP-1 secretion was impaired by bumetanide but not bendrofluazide, suggesting that a high intracellular [Cl-] maintained by Na(+)-K(+)-2Cl- cotransporters is necessary for the depolarizing response to glycine receptor ligands. Our results suggest that GABA and glycine stimulate electrical activity and GLP-1 release from GLUTag cells by ligand-gated ion channel activation, a mechanism that might be important in responses to endogenous ligands from the enteric nervous system or dietary sources.

Action Potentials↗
PubMed2005

Extrarenal Wilms' tumor of the uterine corpus.

BACKGROUND: Extrarenal Wilms' tumors (EWT) are rare. In the female genital tract, only 15 cases (6 adults, 9 children) of EWT have been reported. A case of uterine Wilms' tumor in an adult is presented with a review of the literature. CASE: A 44-year-old woman presented with a bleeding polypoid cervical mass. Biopsy revealed EWT. She was surgically staged, received chemotherapy, and is without evidence of disease at 1 year follow-up. CONCLUSIONS: Prognosis and treatment of EWT may differ by location and patient age. Literature review of uterine Wilms' tumor reveals favorable outcome with (1) focal disease confined to the uterus and (2) adequate surgery, including hysterectomy. The National Wilms' Tumor Study Group recommends adjuvant chemotherapy for all EWT. Radiation may be reserved for patients with residual, metastatic and/or recurrent disease.

Adult↗
PubMed2005

Leptin: a potential cognitive enhancer?

It is well documented that the hormone leptin signals information regarding the status of fat stores to hypothalamic nuclei, which in turn control feeding behaviour and body weight. However, leptin and its receptor are widely expressed in many extra-hypothalamic brain regions, including hippocampus, brain stem and cerebellum. Moreover, evidence is accumulating that leptin has other neuronal functions that are unrelated to its effects on energy homeostasis. Indeed a role for leptin in neuronal development has been suggested as leptin-deficient rodents display abnormal brain development and leptin actively participates in the development of the hypothalamus. In the hippocampus, leptin is a potential cognitive enhancer as genetically obese rodents with dysfunctional leptin receptors display impairments in hippocampal synaptic plasticity. Moreover, direct administration of leptin into the hippocampus can facilitate hippocampal LTP (long-term potentiation) in vivo and improve memory processing in mice. At the cellular level, we have also shown that leptin has the capacity to convert short-term potentiation into LTP. Here, we review the data that leptin influences hippocampal synaptic plasticity via enhancing NMDA (N-methyl-D-aspartate) receptor function. We also provide evidence that rapid trafficking of NMDA receptors to the plasma membrane may underlie the effects of leptin on excitatory synaptic strength.

Animals↗
PubMed2004

Patients with uterine papillary serous cancers may benefit from adjuvant platinum-based chemoradiation.

OBJECTIVE: The coexistence of minimal uterine disease and extrauterine metastases is common in patients with uterine papillary serous carcinoma (UPSC). Only complete surgical staging accurately depicts the extent of this disease. The purpose of this study was to evaluate different therapeutic options in surgically staged patients. METHODS: We retrospectively reviewed all patients with UPSC histologically limited in the uterus to the endometrium treated at our institution between 1987 and 2002. RESULTS: Twenty-three (45%) cases were International Federation of Gynecology and Obstetrics (FIGO) stage IA, seven (15%) were stage IIIA, one (2%) was stage IIIC, and nine (18%) stage IV. Additionally, 11 of these 51 patients (21%) were diagnosed with two cancers: a stage IA UPSC and concomitant advanced stage serous cancer of the ovary, fallopian tube, or peritoneum. Stage IA patients with no cancer in the hysterectomy specimen (defined as no residual uterine disease) had no recurrences (n = 10) regardless of treatment. There was a trend toward increased survival in stage IA patients with residual uterine disease who were treated with chemoradiation (concomitant vaginal brachytherapy and platinum-based chemotherapy). There were no recurrences in patients with locoregional disease (stages IA-IIIA) who received chemoradiation. All patients with advanced stage UPSC (stage IIIC or IV or two primary cancers) did poorly regardless of treatment. CONCLUSION: Our findings suggest that stage IA patients with no residual uterine disease may be observed. Stage IA patients with residual uterine disease may benefit from chemoradiation. More effective treatment needs to be identified for advanced stage UPSC.

Aged↗
PubMed2003

Comparing EST-based genetic maps between Pinus sylvestris and Pinus taeda.

A genetic map of Pinus sylvestris was constructed using ESTP (expressed sequence tag polymorphism) markers and other gene-based markers, AFLP markers and microsatellites. Part of the ESTP markers (40) were developed and mapped earlier in Pinus taeda, and additional markers were generated based on P. sylvestris sequences or sequences from other pine species. The mapping in P. sylvestris was based on 94 F(1) progeny from a cross between plus-tree parents E635C and E1101. AFLP framework maps for the parent trees were first constructed. The ESTP and other gene sequence-based markers were added to the framework maps, as well as five published microsatellite loci. The separate maps were then integrated with the aid of AFLPs segregating in both trees (dominant segregation ratios 3:1) as well as gene markers and microsatellites segregating in both parent trees (segregation ratios 1:1:1:1 or 1:2:1). The integrated map consisted of 12 groups corresponding to the P. taeda linkage groups, and additionally three and six smaller groups for E1101 and E635C, respectively. The number of framework AFLP markers in the integrated map is altogether 194 and the number of gene markers 61. The total length of the integrated map was 1,314 cM. The set of markers developed for P. sylvestris was also added to existing maps of two P. taeda pedigrees. Starting with a mapped marker from one pedigree in the source species resulted in a mapped marker in a pedigree of the other species in more than 40% of the cases, with about equal success in both directions. The maps of the two species are largely colinear, even if the species have diverged more than 70 MYA. Most cases of different locations were probably due to problems in identifying the orthologous members of gene families. These data provide a first ESTP-containing map of P. sylvestris, which can also be used for comparing this species to additional species mapped with the same markers.

Base Sequence↗
PubMed2002

Leptin inhibits epileptiform-like activity in rat hippocampal neurones via PI 3-kinase-driven activation of BK channels.

The obese gene product, leptin is an important circulating satiety factor that regulates energy balance via its actions in the hypothalamus. However, leptin receptors are also expressed in brain regions not directly associated with energy homeostasis, such as the hippocampus. Here, leptin inhibits hippocampal neurones via activation of large conductance Ca(2+)-activated K(+) (BK) channels, a process that may be important in regulating neuronal excitability. We now show that leptin receptor labelling is expressed on somata, dendrites and axons, and is also concentrated at synapses in hippocampal cultures. In functional studies, leptin potently and reversibly reduces epileptiform-like activity evoked in lean, but not leptin-resistant Zucker fa/fa rats. Furthermore, leptin also depresses enhanced Ca(2+) levels evoked following Mg(2+) removal in hippocampal cultures. The ability of leptin to modulate this activity requires activation of BK, but not K(ATP), channels as the effects of leptin were mimicked by the BK channel activator NS-1619, and inhibited by the BK channel inhibitors, iberiotoxin and charybdotoxin. The signalling mechanisms underlying this process involve stimulation of phosphoinositide 3-kinase (PI 3-kinase), but not mitogen-activated protein kinase (MAPK), as two structurally unrelated inhibitors of PI 3-kinase, LY294002 and wortmannin, blocked the actions of leptin. These data indicate that leptin, via PI 3-kinase-driven activation of BK channels, elicits a novel mechanism for controlling neuronal excitability. As uncontrolled excitability in the hippocampus is one underlying cause of temporal lobe epilepsy, this novel action of leptin could provide an alternative therapeutic target in the management of epilepsy.

Adenosine Triphosphate↗
PubMed2002

A phase I trial of antibody directed enzyme prodrug therapy (ADEPT) in patients with advanced colorectal carcinoma or other CEA producing tumours.

Antibody-directed enzyme prodrug therapy is a targeted therapy in which a prodrug is activated selectively at the tumour site by an enzyme, which has been targeted to the tumour by an antibody (antibody-enzyme conjugate). Previous clinical trials have shown evidence of tumour response, however, the activated drug had a long half-life, which resulted in dose-limiting myelosuppression. Also, the targeting system, although giving high tumour to blood ratios of antibody-enzyme conjugate (10 000 : 1) required administration of a clearing antibody in addition to the antibody-enzyme conjugate. The purpose of this current study therefore was to attempt tumour targeting of the antibody-enzyme conjugate without the clearing antibody, and to investigate a new prodrug (bis-iodo phenol mustard, ZD2767P) whose activated form is highly potent and has a short half-life. Twenty-seven patients were treated with antibody-directed enzyme prodrug therapy using A5CP antibody-enzyme conjugate and ZD2767P prodrug, in a dose-escalating phase I trial. The maximum tolerated dose of ZD2767P was reached at 15.5 mg m(-2)x three administrations with a serum carboxypeptidase G2 level of 0.05 U ml(-1). Myelosuppression limited dose escalation. Other toxicities were mild. Patients' quality of life was not adversely affected during the trial as assessed by the measures used. There were no clinical or radiological responses seen in the study, but three patients had stable disease at day 56. Human anti-mouse antibody and human anti-carboxypeptidase G2 antibody were produced in response to the antibody enzyme conjugate (A5CP). The antibody-enzyme conjugate localisation data (carboxypeptidase G2 enzyme levels by HPLC on tumour and normal tissue samples, and gamma camera analysis of I-131 radiolabelled conjugate) are consistent with inadequate tumour localisation (median tumour: normal tissue ratios of antibody-enzyme conjugate of less than 1). A clearance system is therefore desirable with this antibody-enzyme conjugate or a more efficient targeting system is required. ZD2767P was shown to clear rapidly from the circulation and activated drug was not measurable in the blood. ZD2767P has potential for use in future antibody-directed enzyme prodrug therapy systems.

Adult↗
PubMed2000

Antibody-directed enzyme prodrug therapy: efficacy and mechanism of action in colorectal carcinoma.

In antibody-directed enzyme prodrug therapy, an enzyme conjugated to an antitumor antibody is given i.v. and localizes in the tumor. A prodrug is then given, which is converted to a cytotoxic drug selectively in the tumor. Ten patients with colorectal carcinoma expressing carcinoembryonic antigen received antibody-directed enzyme prodrug therapy with A5B7 F(ab')2 antibody to carcinoembryonic antigen conjugated to carboxypeptidase G2 (CPG2). A galactosylated antibody directed against the active site of CPG2 (SB43-gal) was given to clear and inactivate circulating enzyme. A benzoic acid mustard-glutamate prodrug was given when plasma enzyme levels had fallen to a predetermined safe level, and this was converted by CPG2 in the tumor into a cytotoxic form. Enzyme levels derived from quantitative gamma camera imaging and from direct measurements in plasma and tumor biopsies showed that the median tumor:plasma ratio of enzyme exceeded 10000:1 at the time of prodrug administration. Enzyme concentrations in the tumor (median, 0.47 units g(-1)) were sufficient to generate cytotoxic levels of active drug. The concentration of prodrug needed for optimal conversion (Km) of 3 microM was achieved. Prodrug conversion to drug was shown by finding detectable levels of drug in plasma. There was evidence of tumor response; one patient had a partial response, and six patients had stable disease for a median of 4 months after previous tumor progression (one of these six had a tumor marker response). Manageable neutropenia and thrombocytopenia occurred. Conditions for effective antitumor therapy were met, and there was evidence of tumor response in colorectal cancer.

Adult↗
PubMed2000

Radioimmunoguided surgery in colorectal cancer using a genetically engineered anti-CEA single-chain Fv antibody.

In radioimmunoguided surgery (RIGS), a radiolabeled antibody is given i.v. before surgery and a hand-held gamma-detecting probe is used to locate tumor in the operative field. The rapid blood clearance and good tumor penetration of single-chain Fv antibodies (scFv) offer potential advantages over larger antibody molecules used previously for RIGS. A Phase I clinical trial is reported on RIGS with scFv (MFE-23-his) to carcinoembryonic antigen (CEA). Thirty-four patients undergoing surgery for colorectal carcinoma (17 primary tumors, 16 liver metastases, and 1 anastomotic recurrence) and 1 patient with liver metastases of pancreatic carcinoma received 125I-labeled MFE-23-his scFv (125I-MFE-23-his) 24, 48, 72, or 96 h before operation. 125I-MFE-23-his showed biexponential blood clearance with alpha and beta half-lives of 0.32 and 10.95 h, respectively. The abdomen was scanned during surgery with a hand-held gamma detecting probe (Neoprobe Corp.). 125I-MFE-23-his showed good tumor localization; comparison with histology showed overall accuracy of 84%. Highest median ratios for tumor:normal tissue and tumor:blood were recorded 72 or 96 h after scFv injection for patients undergoing resection of liver metastases. High levels of radioactivity were found in the kidneys. Five patients had grade 1 fever, and three had a grade 1 rise in blood pressure according to the Common Toxicity Criteria. There was a significant correlation between these ratios and those measured in excised tissues using a laboratory gamma counter (P < 0.001). MFE-23-his scFv antibody localizes in CEA-producing carcinomas. The short interval between injection and operation, the lack of significant toxicity, and the relatively simple production in bacteria make MFE-23-his scFv suitable for RIGS.

Adult↗
PubMed1999

Peroneal tendon subluxation in athletes: new exam technique, case reports, and review.

Traumatic peroneal tendon subluxation is an uncommon cause of ankle pain. As a result, the diagnosis is often delayed. A new technique of examining the patient in the prone position, allowing for easier visualization of the subluxation or dislocation, is described. Three illustrative cases, including a rare case of midsubstance rupture of the peroneal retinaculum are presented along with a review the literature. An acute repair in athletes and in those patients who do not want to risk the chance of a 40-50% failure rate after 4-6 wk of casting is currently recommended. Surgical repair can be facilitated using Mitek suture anchors for acute, symptomatic chronic, and subacute injuries. Deepening of the groove is performed only in those patients that have no sulcus or a convexity of the groove.

Adolescent↗
PubMed1999

Development of dosing guidelines for reaching selected target breath alcohol concentrations.

OBJECTIVE: This study evaluated gender-specific ethanol dosing protocols that were designed to result in one of two peak breath alcohol concentrations (BrACs)--0.07 or 0.10 g/2101. Inter- and intrasubject variability in BrAC were assessed and several possible methods for reducing variability in BrAC were evaluated. METHOD: Subjects (16 women, 16 men, ages 21-30 years) were studied after low (women 0.49 g/kg, men 0.53 g/kg consumed over 10 minutes) and high (women 0.81 g/kg, men 0.89 g/kg consumed over 20 minutes) ethanol doses, consumed following a 4-hour fast. All subjects were regular drinkers. RESULTS: Mean (+/-SD) peak BrACs actually achieved were 0.069+/-0.011 g/2101 after the low dose, and 0.105+/-0.014 g/2101 after the high dose. Mean values for peak BrAC, time to peak BrAC and area under the curve were not statistically significantly different between genders at either dose. BrACs varied by as much as twofold between subjects after equivalent gender and body weight adjusted doses. There was some reproducibility of ethanol pharmacokinetic parameters over dose and time in men, but not in women. CONCLUSIONS: The doses used resulted in equivalent mean ethanol exposures for women and men at each dose, with mean peak BrACs that closely approached the targets, but there was substantial inter- and intrasubject variability in ethanol pharmacokinetics.

Adult↗
PubMed1998

Binding and uptake of biodegradable poly-DL-lactide micro- and nanoparticles in intestinal epithelia.

The use of biodegradable particles as oral delivery vehicles for macromolecular drugs was investigated. We evaluated the binding, uptake and absorption of poly-dl-lactide (PLA) micro- and nanoparticles in Caco-2 monolayers and in ileal tissue and gut associated lymphoid tissue (GALT) of anaesthetised rats and rabbits. Using a range of experimental techniques, we found that approximately 10% of administered micro- and nanoparticles were adsorbed to the apical membranes of each of the five intestinal models. Nanoparticles were found to be absorbed better than microparticles. Overall, little discrimination in uptake patterns was evident between Peyer's patch (PP) and non-PP tissue while rat ileum showed a greater uptake capacity than rabbit. Our results show that uptake of PLA particles was low capacity, size-dependent and predominantly transcellular in all systems. A low proportion of the apically-bound particles was absorbed, with uptake exclusion evident for particles >4microm. The affinity of PLA particles for intestinal epithelia and GALT needs to be greatly enhanced in order to achieve improved oral bioavailability of macromolecules.

Animals↗
PubMed1998

A vertical curriculum to teach the knowledge, skills, and attitudes of medical informatics.

It is becoming increasingly apparent that medical schools must begin teaching the knowledge, skills and attitudes of information literacy and applied medical informatics as core competencies in undergraduate medical education. The University of Vermont College of Medicine recognized that these core competencies were lacking in its curriculum, and in 1992 it implemented a four year, integrated program to give students the information habits essential to twenty-first century practice. The first graduates of the program are now in residencies and feedback has enabled the College to refine the program to better meet the informatics education needs of the next generation of physicians. The result of these efforts is the Vertical Curriculum in Information Literacy and Applied Medical Informatics; its process of development, the product of the process, and its outcomes are discussed.

Computer Literacy↗
PubMed1997

The importance of measuring quality of life in phase I/II trials of cancer therapy--the effects of antibody targeted therapy: Part I.

Phase I/II trials of new cancer therapies are designed to determine safety, efficacy and the optimal regimen for treatment. In order to uphold the principle that 'the interests of the subject must prevail over the interests of science and society' as laid down in the Declaration of Helsinki the effects of these trials on quality of life must be determined. Antibody-targeted therapies are a new form of cancer therapy designed to selectively deliver cytotoxic agents to cancer cells. Twenty-four patients with advanced colorectal cancer were enrolled into trials of three different treatment modalities based on this theme. Quality of life was measured using the Hospital Anxiety and Depression Scale and the Rotterdam Symptom Checklist prior to and 4 weeks after treatment. The Common Toxicity Criteria of the NCI were used to assess treatment related toxicity. There was no significant difference between pre- and post-treatment scores for all three treatment modalities. There was also no significant correlations between toxicity and physical or psychological morbidity. We suggest that the quality of life of patients undergoing phase I/II clinical trials with antibody targeted therapies for metastatic colorectal carcinoma was not adversely affected. We feel that in part this can be attributed to the high level and the intensity of support provided for the patients undergoing these treatments.

Adult↗
PubMed1992

The Devereux Adolescent Behavior Rating Scale: a tentative model of second-order factor structure across independent clinical samples.

The second-order factor structure of the Devereux Adolescent Behavior Rating Scale was examined in (a) a sample of 254 adolescents who were receiving residential treatment for severe emotional/behavior disorders and (b) an independent sample of 404 adolescents hospitalized for substance abuse. A plausible range of factors was estimated for each group through parallel and average partial analyses and suggested wither a two- or three-factor solution. Subsequent congruence analyses provided tentative support for a three-factor model: (a) undercontrolled/disruptive behaviors; (b) withdrawn/psychotic behaviors; and (c) needs approval/dependent behaviors. The third factor was poorly defined in the residential treatment sample, but extraction of the third factor increased the across-group replicability of the first two factors.

Adolescent↗
PubMed1988

Acute pseudogout mimicking septic arthritis following urologic manipulation.

An 80-year-old man presented with an acute, rapidly worsening synovitis with a hot effusion of the right knee approximately 48 hours following a urologic procedure. Initial aspirates failed to reveal crystals and suggested an acute infectious arthritis. Because his course continued to deteriorate despite adequate antibiotic treatment, the patient underwent arthroscopy in order to place tubes and to effect adequate irrigation and debridement. The preoperative diagnosis was septic arthritis. At the time of arthroscopy, there was gross evidence of crystals that were subsequently diagnosed as calcium pyrophosphate. This case illustrates the importance of an adequate differential diagnosis and the usefulness of the arthroscope in obtaining adequate tissue and aspirate under confusing circumstances.

Aged↗