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Biomedical subjects

J Mahoney

Publications and source records attributed to J Mahoney.

At least 19 recordsLinked to original sources
PubMed2005

Electron-impact ionization of silicon tetrachloride (SiCl4).

We measured absolute partial cross sections for the formation of various singly charged and doubly charged positive ions produced by electron impact on silicon tetrachloride (SiCl4) using two different experimental techniques, a time-of-flight mass spectrometer (TOF-MS) and a fast-neutral-beam apparatus. The energy range covered was from the threshold to 900 eV in the TOF-MS and to 200 eV in the fast-neutral-beam apparatus. The results obtained by the two different experimental techniques were found to agree very well (better than their combined margins of error). The SiCl3(+) fragment ion has the largest partial ionization cross section with a maximum value of slightly above 6x10(-20) m2 at about 100 eV. The cross sections for the formation of SiCl4(+), SiCl+, and Cl+ have maximum values around 4x10(-20) m2. Some of the cross-section curves exhibit an unusual energy dependence with a pronounced low-energy maximum at an energy around 30 eV followed by a broad second maximum at around 100 eV. This is similar to what has been observed by us earlier for another Cl-containing molecule, TiCl4 [R. Basner, M. Schmidt, V. Tamovsky, H. Deutsch, and K. Becker, Thin Solid Films 374 291 (2000)]. The maximum cross-section values for the formation of the doubly charged ions, with the exception of SiCl3(++), are 0.05x10(-20) m2 or less. The experimentally determined total single ionization cross section of SiCl4 is compared with the results of semiempirical calculations.

Journal Article↗
PubMed2004

Peripheral blood mononuclear cell DNA 6-thioguanine metabolite levels correlate with decreased interferon-gamma production in patients with Crohn's disease on AZA therapy.

6-Mercaptopurine (6-MP) and its prodrug azathioprine (AZA) are well known for their lymphocytotoxic and bone marrow suppressive effects in the management of patients with leukemia. Although their immunosuppressive properties are mediated by the active AZA antimetabolite 6-thioguanine (6-TG), its mechanism of action is largely unknown. In IBD, a significant inverse correlation has been shown between erythrocyte 6-TG metabolite levels and disease activity, further supporting the proposed immunosuppressive role for 6-TG. Since leukocytes possess quantitatively different purine metabolic pathways compared to erythrocytes, this study aims to measure lymphocyte DNA 6-TG metabolites and correlate levels with the INF-gamma and IL-10 cytokine profile in patients with Crohn's disease (CD). Forty-six adult patients with CD, either naive (17) or on long-term (>4-month) AZA therapy (29), had erythrocyte and lymphocyte DNA 6-TG levels measured by reverse-phase HPLC under UV detection (6-TG, 340 nm). Lymphocyte DNA 6-TG was expressed as picomoles per milligram of DNA. Lymphocyte DNA 6-TG metabolite levels were correlated with INF-gamma and IL-10 cytokine profiles using the OptEIA kit (Pharmigen). Lymphocyte DNA 6-TG metabolite levels correlate with erythrocyte 6-TG levels (P < 0.03) but not total patient leukocyte levels. Erythrocyte 6-TG metabolite levels correlated (P < 0.01) inversely with INF-gamma but not IL-10 cytokine levels. This study suggests a preferential dampening of the TH1 response on exposure to 6-TG and a possible immunosuppressive mechanism of action for AZA. Future studies are needed to determine if cytokine profiles can be used to predict recalcitrant CD to AZA therapy.

Azathioprine↗
PubMed2001

Leadership skills for the 21st century.

In today's ever-changing health care environment, nurses, especially administrators and managers, require leadership skills that provide direction for a new generation of nurses. Currently, there is a shortage of nurses globally. Along with this shortage of nurses, there is a shortage of nurse leaders. The importance of cultivating new nursing leaders is imperative for a healthful society. Gaining knowledge to become an effective nurse leader is one way to ensure quality health care for the future.

Humans↗
PubMed2001

The use of computed tomography to define zygomatic complex position.

PURPOSE: The purpose of this study was to analyze the use of midline references and landmarks to assess the position of the zygomatic complex relative to the cranial base, and to test the reliability of these measurements in assessing facial symmetry. METHODS: Direct skull measurements were compared with measurements made on computed tomography (CT) images. The effect of CT scanner error, technologist error, gantry angle error, error of skull inclination, and error due to the presence of titanium rigid fixation hardware were assessed. To test observer variation and the effect of each level of error, 4 blinded bilateral measurements were repeated 3 times by 5 observers on both dry skull and CT scans. A mixed effect analysis of variance model then assessed for effect of method of measurement (dry skull vs CT), observer, CT scanner, technologist, gantry angle, skull inclination, and rigid fixation. RESULTS: A total of 2,040 measurements were made. Measurements for zygomatic complex posterior and anterior width and height were reliable and had an interobserver variations of 0.02 +/- 0.03 mm, 0.5 +/- 0.4 mm, and 0.37 +/- 0.3 mm, respectively. The difference between dry skull and CT assessment for the 3 reliable measurements was 1.2 +/- 0.3 mm, 0.44 +/- 0.4 mm, and 1.1 +/- 0.5 mm, respectively. The errors produced by the CT scanner, technologist, and rigid internal fixation hardware were not clinically significant. The measurements were not sensitive to gantry angle and skull inclination changes of 10 degrees or less. A fourth measurement assessing zygomatic complex projection was found not to be accurate or reliable. CONCLUSIONS: These findings suggest that the 3 CT scan measurements describing the position of the zygomatic complex relative to the cranial base are clinically useful.

Cephalometry↗
PubMed1999

Mental health services. Poor relations.

The case for London requiring greater resources for mental health services than other parts of the country has not been proved. Liverpool, Birmingham and Manchester are among the six most deprived areas in England. Spending per capita on mental health services in inner London is double that in Birmingham and Liverpool and 40 per cent higher than in Manchester. A national strategy is needed to address inequities in funding.

Age Factors↗
PubMed1999

Digital two-dimensional photogrammetry: a comparison of three techniques of obtaining digital photographs.

Three methods of obtaining digital photographs in a clinical setting were compared using direct anthropometry as a reference standard. The methods included a digital camera, scanning negatives from a 35-mm single-lens reflex camera, and scanning Polaroid photographs taken with a Polaroid camera designed for medical documentation. A total of 11 angular and linear anthropometric measurements obtained from 30 healthy volunteers were used for the comparison. The data were analyzed using a variance covariance approach to repeated measures. The analysis revealed that the three cameras were not statistically different from each other. Other advantages and disadvantages, such as cost and ease of use, are discussed.

Adolescent↗
PubMed1999

Risk factors for lack of recovery of ADL independence after hospital discharge.

OBJECTIVE: To determine risk factors for lack of recovery of independent functioning after hospitalization for acute medical illness. DESIGN: Secondary analysis of cohort study of patients receiving home nursing after discharge. SETTING: Evaluations performed in the home after discharge and 1 month later. PARTICIPANTS: A total of 73 adults aged 65 years and older who were independent in activities of daily living (ADLs) before hospitalization and dependent at discharge. MEASUREMENTS: Self-report and objective measures of function, mobility, and cognition. OUTCOME: Return to independence in ADLs 1 month after discharge. RESULTS: Fifty-nine percent of patients did not return to previous ADL independence by 1 month postdischarge. The likelihood for not recovering was 87% (95% CI, 70-100%) if a patient had a Mini-Mental State Examination score (MMSE) < 24 at discharge (P = .015). Among patients with good cognition, 85% (95% CI, 66-100%) of those who used an assistive device indoors before hospitalization did not recover (P = .007). Among patients with good cognition and no previous assistive device use, 73% (95% CI, 47-99%) of those with a Timed "Up and Go" of > or = 40 seconds did not recover (P = .012). The likelihood of recovery was high (76%, 95% CI 56-96%) if a patient had no assistive device prehospital, a good MMSE, and a Timed "Up and Go" of < 20 seconds. CONCLUSION: We hypothesize that a classification strategy using cognition, prehospital mobility, and discharge physical performance will predict patients who are less likely to recover functional independence after hospitalization. If this is validated in future study, it may help clinicians identify patients who are more likely to benefit from additional intervention.

Activities of Daily Living↗
PubMed1998

Genital infection of female chimpanzees with human immunodeficiency virus type 1.

To develop an animal model for mucosal HIV-1 infection, adult chimpanzees were inoculated without trauma by depositing the virus inoculum at the entrance to the cervical canal with a rigid catheter to which flexible tubing was attached. By this procedure, persistent infections were established in some chimpanzees with various infectious doses of either cell-associated HIV-1LAI(IIIB) (peripheral blood mononuclear cells from an infected chimpanzee) or with cell-free HIV-1 strains representing subtypes B and E, but not with a subtype A strain. Although some animals did not become infected until after the second or third cervicovaginal exposure, one chimpanzee was clearly infected after one exposure by several criteria, including virus isolation, but this animal did not seroconvert. A second chimpanzee appeared to be resistant to infection despite repeated mucosal exposures at irregular intervals. However, lymphocytes from both of these animals exhibited low-level proliferative responses to HIV-1 but not SIV antigens. Despite these apparently abortive or latent infections, after exposure to HIV-1 by the intravenous route, both animals developed systemic infections and seroconverted. Overall, 8 of 10 chimpanzees were infected systemically after one to three cervicovaginal exposures to HIV-1LAI(IIIB). The results indicate that (1) HIV-1 productive infection of female chimpanzees by the cervicovaginal route generally requires more than one exposure, just as with humans; (2) low level infections without seroconversion can be established after mucosal exposure to HIV; and (3) vaccine efficacy studies involving a single virus challenge of immunized chimpanzees by the cervicovaginal route probably will not be possible.

Animals↗
PubMed1998

New Down syndrome screening algorithm: ultrasonographic biometry and multiple serum markers combined with maternal age.

OBJECTIVE: We compared the Down syndrome screening efficiency of a new algorithm that combines humerus length measurement and serum analytes versus that of the traditional triple-analyte serum screen. STUDY DESIGN: Humerus length measurements were obtained prospectively in 1743 midtrimester (14 to 24 weeks) singleton fetuses before genetic amniocentesis. All patients had triple-marker serum screening before amniocentesis. Data on humerus length were expressed as multiples of the median, and were normalized by log transformation. Backward multiple stepwise logistic regression analysis was performed to determine which combination of biometry and serum markers best predicted fetal Down syndrome. The screening efficiency of the traditional triple-analyte algorithm was compared with that of a new multivariate gaussian algorithm that combined biometry and serum markers. RESULTS: There were 31 (1.8%) fetuses with Down syndrome in the study population. In the regression analysis humerus length, human chorionic gonadotropin, alpha-fetoprotein, and maternal age were significant predictors of Down syndrome, but unconjugated estriol was not. The combined algorithm (humerus length, human chorionic gonadotropin, and alpha-fetoprotein and age) was superior to the traditional triple screen for Down syndrome detection. The sensitivities at fixed false-positive rates were consistently higher in the combination than in the triple-screen protocol. For example, at a 10% false-positive rate the sensitivities were 65.0% and 52.3%, respectively. Similarly, at a 15% false-positive rate the sensitivities were 73.5% and 55.0%, respectively. CONCLUSION: A new screening algorithm combining humerus length and serum analytes was superior to the traditional triple screen. Although we used a high-risk population in this study, it is expected that the observed superiority of the combination screen would persist in a population of younger women. The development of a combined biometric and serum analyte screening algorithm for estimating individual odds could represent an advance in prenatal Down syndrome screening.

Algorithms↗
PubMed1998

Diagnosis and treatment of prostatitis in Canada.

OBJECTIVES: There is a general consensus among physicians that the present management of chronic prostatitis is dismal. We undertook a survey of Canadian primary care physicians (PCPs) and urologists to determine the degree and source of frustration and to analyze present practice patterns in this disease. METHODS: Five thousand PCPs and all 545 Canadian urologists were asked to complete a comprehensive computer-assisted telephone survey that explored practice characteristics, attitudes, and diagnostic and treatment strategies in the management of prostatitis. Randomization of attribute banks, adherence to questionnaire routing, validation by on-site monitoring, and possible bias were addressed. RESULTS: Completed interviews were obtained from 10% of PCPs and 28% of urologists. PCPs see on average 3.5 (median 2) patients with prostatitis per month and urologists see on average 21.8 (median 11) patients with prostatitis per month. All physicians experience significantly more frustration in treating prostatitis than they do in treating patients with benign prostatic hyperplasia (BPH) and prostate cancer, and they perceive that prostatitis affects patients' quality of life significantly more than BPH and almost as much as prostate cancer. The degree of frustration and unhappiness in dealing with prostatitis is driven by a lack of confidence and comfort in their ability to accurately diagnose and subsequently rationalize treatment. Most PCPs and urologists continue to employ steps in addition to history and physical examination to establish a diagnosis but only a few PCPs and a third of urologists use specific lower urinary tract cultures. Physicians tend to use trimethoprim or trimethoprim-sulfamethoxazole (TMP-SMX) or a fluoroquinolone as their usual first line therapy for chronic prostatitis. The most commonly used therapeutic strategy (40%) for chronic prostatitis was TMP-SMX as first line therapy and a fluoroquinolone as second line therapy. CONCLUSIONS: There is widespread frustration, discomfort, and lack of confidence in both PCPs' and urologists' perceived ability to manage prostatitis. Physicians have expressed a desire for a better understanding of this disease, simpler and clearer diagnostic guidelines, and more rational treatment strategies.

Canada↗
PubMed1998

An update on efforts by the hospice community and the National Hospice Organization to improve access to quality hospice care.

More than a year has passed since the Center to Improve Care of the Dying and the Corcoran Gallery of Art sponsored the symposium entitled: A Good Dying: Shaping Health Care for the Last Months of Life. Using the National Hospice Foundation sponsored exhibition, Hospice: A Photographic Inquiry, as a backdrop, the symposium included presentations on the current state of hospice care as well as the obstacles that limit access to hospice care. This article represents an update on many of the activities of the National Hospice Organization and the greater hospice community as we continue to improve access to quality hospice care.

Health Services Accessibility↗
PubMed1998

Maxillozygional anthropometric landmark: a new morphometric orientation point in the upper face.

A new anthropometric landmark of the face, called the maxillozygion (mz; right, left) is presented. The bilateral landmark is the most prominent point of the maxillozygomatic suture line, identified by palpation of the most anterior protruding contours on the frontal aspect of the face, located below the lateral third of the right and left bony orbits. The reliability of locating the landmark on both sides of the face by palpation is discussed. Preliminary data determining the position of the maxillozygion in the vertical, sagittal, and horizontal planes in white and Asian sample populations is presented. In general, the Asian face tends to be the same width (zygion [zy]-zy) as the white face; however, the maxillozygion is located more laterally on the Asian face compared with the white face.

Adult↗
PubMed1997

"Spare part" forearm free flaps harvested from the amputated limb for coverage of amputation stumps.

The use of "spare part" flaps from a non-replantable limb to cover amputation stumps in the upper extremity preserves limb length, provides durable coverage and sensation and will avoid additional donor site morbidity. We have studied the blood supply of the forearm based on the radial artery. The potential for harvesting different tissues is confirmed. In five clinical cases reliable primary soft tissue reconstruction was achieved, even in the presence of trauma.

Amputation Stumps↗
PubMed1997

Prevention of rhinovirus infection in chimpanzees by soluble intercellular adhesion molecule-1.

Intercellular adhesion molecule-1 (ICAM-1) is the cell surface receptor for the major class of human rhinoviruses, and tICAM453, a truncated, soluble form of ICAM-1, has been shown previously to be a potent in vitro inhibitor of rhinovirus. In this report, we have investigated the in vivo efficacy of tICAM453 for the prophylaxis of rhinovirus serotype 16 infection in the chimpanzee. Because chimpanzees do not show clinical symptoms of infection after rhinovirus challenge, infection was followed by measuring antirhinovirus serum antibody responses and detection of virus shedding. By both of these measures, intranasal application of tICAM453 was efficacious in preventing rhinovirus infection in chimpanzees subsequently challenged with infectious doses of virus. These results suggest that the use of soluble rhinovirus receptor to inhibit virus binding to host cells should be feasible in humans.

Administration, Intranasal↗