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Biomedical subjects

T O'Donnell

Publications and source records attributed to T O'Donnell.

At least 19 recordsLinked to original sources
PubMed2002

Development of a model for occipital fixation--validation of an analogue bone material.

Several implant systems may be used to fuse the skull to the upper cervical spine (occipitocervical fusion). Current biomechanical evaluation is restricted by the limitations of human cadaveric specimens. This paper describes the design and validation of a synthetic testing model of the occipital bone. Data from thickness measurement and pull-out strength testing of a series of human cadaveric skulls was used in the design of a high-density rigid polyurethane foam model. The synthetic occipital model demonstrated repeatable and consistent morphological and biomechanical properties. The model provides a standardized environment for evaluation of occipital implants.

Biomechanical Phenomena↗
PubMed2002

A prospective study for evaluation of knee effusion after hip surgery.

Knee effusion is a common occurrence in elderly patients following hip surgery. We prospectively studied 106 patients undergoing proximal femoral surgery. These patients were examined pre-operatively, on days 4 and 8, and six weeks post operatively for the presence of an ipsilateral knee effusion. 71 patients had undergone Total Hip Arthroplasty (THA), 26 Dynamic Hip Screw (DHS) insertion and 9 had hemiarthroplasty. The incidence of pre-operative ipsilateral knee effusion was 13% (14 patients). 42% (44 patients) had an effusion at one week post operatively and 12% (13 patients) at 6 weeks. 57% (60 patients) of the study group had radiological evidence of osteoarthritis in their knees. However, the incidence of effusion in patients with and without arthritis was the same. The majority of these effusions resolved after six weeks with no residual effects.

Aged↗
PubMed2001

Treatment of vinorelbine-associated tumor pain.

Vinorelbine is a synthetic vinca alkaloid used for the treatment of Hodgkin's disease and metastatic breast, non-small-cell lung, and ovarian cancers. Vinorelbine-associated tumor pain can be so severe that patients are unable to complete therapy. We present a series of three patients who were premedicated with ketorolac in an attempt to control infusion-related pain. Two of our patients responded well and were able to complete their courses of vinorelbine therapy. The third had persistently severe pain, and therapy was terminated because of pain and lack of response to vinorelbine treatment. These three cases support the hypothesis that surgery or radiation therapy before the use of vinorelbine may increase the likelihood of experiencing associated tumor pain. Premedication with ketorolac and morphine before vinorelbine infusion is proposed as a reasonable prophylactic treatment for associated tumor pain.

Adult↗
PubMed2000

Chronic lithium and sodium valproate both decrease the concentration of myo-inositol and increase the concentration of inositol monophosphates in rat brain.

One of the mechanisms underlying lithium's efficacy as a mood stabilizer in bipolar disorder has been proposed to be via its effects on the phosphoinositol cycle (PI-cycle), where it is an inhibitor of the enzyme converting inositol monophosphates to myo-inositol. In contrast, sodium valproate, another commonly used mood stabilizer, appears to have no direct effects on this enzyme and was thus believed to have a different mechanism of action. In the present study, high resolution nuclear magnetic resonance (NMR) spectroscopy was used to study the chronic effects of both lithium and sodium valproate on the concentrations of myo-inositol and inositol monophosphates in rat brain. As predicted, lithium-treated rats exhibited a significant increase in the concentration of inositol monophosphates and a significant decrease in myo-inositol concentration compared to saline-treated controls. However, unexpectedly, sodium valproate administration produced exactly the same results as lithium administration. These novel findings suggest that both lithium and sodium valproate may share a common mechanism of action in the treatment of bipolar disorder via actions on the PI-cycle.

Animals↗
PubMed1999

Screening for urinary tract infections in a gynaecological setting: validity and cost-effectiveness of reagent strips.

This study aims to test the validity and cost-effectiveness of reagent-strip analysis compared with microbiological laboratory testing for mass screening of urine for urinary tract infections in a gynaecological setting. Over a six-month period, urine samples from a convenient group of 228 women presenting in a gynaecological ward of an NHS Trust hospital were tested using Ames 8SG reagent strips to detect leucocyte esterase and nitrite. Total bacterial counts were also carried out; urine culture was recorded as positive if there was > 10(5) organisms/mL. Validity of the dipstick tests was measured, using four criteria (sensitivity, specificity, positive predictive value [PPV] and negative predictive value [NPV]), against the results of laboratory analysis. The combined use of the leucocyte esterase and nitrite tests produced results as follows: sensitivity, 96.4%; specificity, 88.5%; PPV, 54%; and NPV, 99.4%. Cost-effectiveness for visible costs was calculated as 48.6% for the 12.3% rate of infection in this study. The use of reagent strips in a mass-screening programme in a gynaecological setting proved both valid and cost-effective.

Cost-Benefit Analysis↗
PubMed1998

Tritiated-naloxone binding to brainstem opioid receptors in the sudden infant death syndrome.

The sudden infant death syndrome (SIDS) is defined as the sudden death of an infant under 1 year of age that remains unexplained after a thorough case investigation, including a complete autopsy. We hypothesized that SIDS is associated with altered 3H - naloxone binding to opioid receptors in brainstem nuclei related to respiratory and autonomic control. We analyzed 3H - naloxone binding in 21 regions in SIDS and control brainstems using quantitative tissue receptor autoradiography. Three groups were analyzed: SIDS (n = 45); acute controls (n = 14); and a chronic group with oxygenation disorders (n = 15). Opioid binding was heavily concentrated in the caudal nucleus of the solitary tract, nucleus parabrachialis medialis, spinal trigeminal nucleus, inferior olive, and interpeduncular nucleus in all cases analyzed (n = 74). The arcuate nucleus on the ventral medullary surface contained negligible binding in all cases (n = 74), and therefore binding was not measurable at this site. We found no significant differences among the three groups in the age-adjusted mean 3H - naloxone binding in 21 brainstem sites analyzed. The only differences we have found to date between SIDS and acute controls are decreases in 3H - quinuclidinyl benzilate binding to muscarinic cholinergic receptors and in 3H - kainate binding to kainate receptors in the arcuate nucleus in alternate sections of this same data set. The present study suggests that there is not a defect in opioid receptor binding in cardiorespiratory nuclei in SIDS brainstems.

Autoradiography↗
PubMed1998

Oesophagitis-induced changes in capsaicin-sensitive tachykininergic pathways in the ferret lower oesophageal sphincter.

Prolonged oesophageal acidification may impair lower oesophageal sphincter (LOS) function in reflux disease. The aim of this study was to investigate aspects of altered LOS innervation in a model of oesophagitis. Oesophagitis was induced by acid (HCl, 0.15 M) and pepsin (0.1% w/v) infusions in anaesthetized ferrets. LOS muscle strip responses to the following stimuli were measured in vitro from control and acid/pepsin-treated ferrets: electrical field stimulation (EFS; 1-50 Hz), potassium chloride KCl; 20 mM), substance P, [beta-Ala8]-neurokinin A 4-10, [Sar9, Met (O2)11]-substance P (all 10(-10) to 10(-6) M) and capsaicin (10(-8) to 10(-6) M). LOS relaxation occurred in response to all stimuli except [beta-Ala8]-neurokinin A 4-10, which evoked contraction. In muscle strips from acid/pepsin-treated animals there were no differences in amplitude or sensitivity of relaxation following EFS, KCl or substance P vs controls. However, the inhibitory response to capsaicin was increased four-fold (10(-8) M; P < 0.05) and an increased sensitivity of the inhibitory response to [Sar9, Met (O2)11]-substance P occurred (pD2 = 8.64 +/- 0.12 acid/pepsin-treated vs 7.94 +/- 0.24 control, P < 0.05). We conclude that in acute oesophagitis, increased sensitivity of capsaicin-activated inhibitory pathways occurs in which activation of NK-1 receptors plays an integral role in the ferret LOS.

Animals↗
PubMed1997

A scientific plan for the evaluation of alternative medicine in the treatment of HIV/AIDS.

The Bastyr University AIDS Research Center was established in October 1994 through a 3-year cooperative grant with the Office of Alternative Medicine, National Institutes of Health. The mission of the Center is to (1) describe forms and patterns of use of alternative medical therapies for HIV infection and AIDS prescribed by practitioners and self-administered by HIV-positive patients in the United States, (2) screen and evaluate therapies for HIV/AIDS from five program areas of alternative medicine, and (3) provide consultation and support in the scientific evaluation of alternative therapies. To meet these goals, the Center has established a network of cooperating alternative medicine clinics and is recruiting HIV-positive men and women who are using alternative medicine to participate in the study. It is collecting data every 6 months from 1500 HIV-positive patients throughout the United States and has created a centralized database to compare outcomes (CD4+ lymphocytes, HIV RNA, CDC class progression, weight, quality of life, and survival) for a variety of alternative therapies. The Center will determine whether patients who use both conventional medicine and alternative medicine have different outcomes from patients who use only conventional medicine. The occurrence of AIDS-related opportunistic infections and neoplasms in HIV-positive patients who are using specific alternative therapies will be compared with the incidence in those who use other medical treatment. This article describes the scientific plan for the study.

Acquired Immunodeficiency Syndrome↗
PubMed1995

Onset of menses in two adult patients with Prader-Willi syndrome treated with fluoxetine.

Prader-Willi syndrome (PWS) is characterized by hypotonia at birth, hypogonadism, early childhood obesity, and mental deficiency. Hypogonadotropic hypogonadism is a major characteristic of patients with PWS, and it is speculated to be due to hypothalamic insufficiency. Two adult female patients with PWS and no prior history of menses are presented. Both of these patients were treated with fluoxetine for psychopharmacologic management of obsessive features in the form of food preoccupation and hyperphagia or for compulsive behaviors in the form of severe self-injurious behaviors. The two female patients with PWS who had primary amenorrhea developed vaginal bleeding believed to be menses following at least 6 months of treatment with fluoxetine. Mature hypothalamic function is characterized by pulsatile release of gonadotropin-releasing hormone (GnRH) in a critical range of frequency and amplitude. Central nervous system neurotransmitters may modify GnRH secretion. Fluoxetine specifically inhibits the reuptake of serotonin which may impact the hypothalamic-pituitary-ovarian system in female patients with PWS.

Adult↗
PubMed1993

Treatment of upper airway obstruction associated with goiter.

The authors examined the resolution of spirometric indices of upper airway obstruction (UAO) following surgical treatment for goiter. The results of a recent study suggest that the integrity of the upper airway remains intact but prolonged recovery is required.

Adult↗
PubMed1992

Pulmonary complications of acute myelogenous leukemia.

Pulmonary complications of acute myelogenous leukemia are attributed to infection, hemorrhage, or toxicity from chemotherapeutic agents. Rarely, damaged leukemic blast cells in lung parenchyma result in chest x-ray abnormalities and respiratory symptoms.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1988

Treatment of cardiogenic shock by emergency aortic balloon valvuloplasty.

We used aortic balloon valvuloplasty to successfully treat two patients who had cardiogenic shock associated with calcific aortic stenosis. In both patients, the resulting reduction in mean aortic valve gradient and increase in calculated aortic valve area allowed prompt discontinuation of treatment with pressors and a return to near normal renal function. Both patients were discharged within 10 days after valvuloplasty and showed significant, long-lasting clinical improvement. Aortic balloon valvuloplasty can reverse cardiogenic shock associated with calcific aortic stenosis.

Aged↗
PubMed1976

Relation between postphlebitic changes in the deep veins and results of surgical treatment of venous ulcers.

41 patients with venous ulceration, investigated by ascending phlebography, had operations to ligate incompetent calf perforating veins. Recurrent ulceration developed within five years of operation in all 23 patients with evidence of deep-vein damage on the initial phlebograms. Only 1 of the seventeen patients with normal deep veins had a recurrent ulcer during the same period of follow-up. Thus local surgery to the perforating veins in postphlebitic limbs was shown to be ineffective.

Adult↗
PubMedDate not supplied

Intravascular ultrasound estimation of arterial stenosis.

The evaluation of the degree of reduction in the cross-sectional area of an artery has important pathophysiologic and therapeutic implications. Currently, no technique can easily provide this information. In this in vitro study we evaluated the potential of a new imaging technique, intravascular high frequency ultrasound angioscopy, in the estimation of percentage of cross-sectional area stenosis of an artery. To do this, we compared intravascular high frequency ultrasound to previously-validated external high frequency ultrasound and to anatomic estimation of arterial stenosis. Using a prototype intraluminal imaging catheter with a 20 MHz ultrasound transducer at its tip, we imaged 20 arterial segments of various size (15 to 90 mm2 lumen area by anatomy) in the control state and after experimental stenosis. These arterial segments were also imaged by external high frequency ultrasound. Lumen areas were measured from calibrated ultrasound images in the control state and after stenosis, and percentage of cross-sectional area stenosis was calculated. These data were compared to the percentage of area stenosis derived from calibrated anatomic photographs of the arteries taken in the control state and after stenosis. Both intravascular ultrasound angioscopy and external high frequency ultrasound yielded high-resolution, two-dimensional, circumferential images of the arteries. Alterations in vessel area and shape were apparent after creation of stenosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Arteries↗
PubMedDate not supplied

Morphine-Infused silver sulfadiazine (MISS) cream for burn analgesia: a pilot study.

Pain is considered the most distressing symptom of a burn wound, with analgesia usually provided via oral or parenteral medications. Use of systemic opioids can be complicated by fluctuations in bioavailability, absorption, and clearance of drugs caused by the burn. There has been little research done in the area of topical medications for burn analgesia. The following is a double-blind, placebo-controlled pilot study assessing the safety (side effects) and efficacy (pain ratings and medications administered) of morphine-infused silver sulfadiazine cream for burn pain. Four patients are reported on (2 in each group). Only participants taking placebo reported side effects related to morphine and necessitated anxiolytic medications. Pain ratings in the treatment group ranged from 0 to 7 with a mean of 2.1, whereas the placebo group's ratings ranged from 2 to 8 with a mean of 5.6. The placebo group averaged 55.3 mg oral morphine per half day, whereas the treatment group averaged 42.9 mg.

Administration, Topical↗
PubMedDate not supplied

Tibial hemimelia of a different class.

A variant of tibial hemimelia, previously undescribed in the literature and not classifiable by either of the established classification systems, is described. The features of this condition include a short, deformed tibia; proximal subluxation of the fibula at the knee; a normal knee joint and an ankle joint that may look abnormal but falls short of true diastasis of the joint. Treatment of two cases by differential lengthening of the tibia and fibula using the Ilizarov device is described. This form of tibial hemimelia should be recognised as a separate variant as preservation of the foot and ankle with expected excellent function should be possible, unlike the more severe forms of this condition.

Age Factors↗