PubMed Health⌕ Search

Biomedical subjects

L Cannon

Publications and source records attributed to L Cannon.

At least 19 recordsLinked to original sources
PubMed2006

The safety and efficacy of the StarClose Vascular Closure System: the ultrasound substudy of the CLIP study.

BACKGROUND: The StarClose Vascular Closure System (Abbott Vascular, Redwood City, CA) features a nitinol clip that is designed to achieve closure of the femoral arteriotomy access site. The CLIP Study was performed to assess the safety and efficacy of StarClose when compared with standard manual compression following 5-6 French diagnostic or interventional percutaneous procedures. A substudy of this trial was designed to assess the utility of duplex ultrasonography to assess patency of the femoral artery and to determine access site complications (pseudoaneurysm, arteriovenous fistula, hematoma, deep vein thrombosis) in a multicenter prospective trial. This is the report of the duplex ultrasound (DUS) substudy of the CLIP trial. METHODS: A total of 17 U.S. sites enrolled 596 subjects with 483 subjects randomized at a 2:1 ratio to receive StarClose or manual compression of the arteriotomy after a percutaneous procedure. The study included roll-in (n = 113), diagnostic (n = 208), and interventional (n = 275) arms with a primary safety endpoint of major vascular complications through 30 days and a primary efficacy endpoint of postprocedure time to hemostasis. A substudy of the CLIP interventional arm evaluated DUS images of the closure site at five study sites, targeting 100 subjects at day 30 following hemostasis. The DUS protocol was devised and implemented by an independent vascular ultrasound core laboratory with extensive experience in vascular device trials. DUS inguinal region from 6 cm proximal to 6 cm distal to the arteriotomy puncture was performed. A qualitative examination was performed to determine the presence of iatrogenic vascular injuries: hematoma, pseudoaneurysm (PSA), arteriovenous fistula (AVF), and arterial/venous thrombosis or stenosis using 2-dimensional gray scale, color, and focused Doppler images. RESULTS: DUS of 96 subjects randomized to StarClose (n = 71) and compression (n = 25) were performed and evaluated. There was no evidence of hematoma, PSA, or AVF observed in the StarClose group. No StarClose subjects in the substudy had a PSA or AVF. All patients in the substudy demonstrated patency of the access site artery and vein without thrombosis or stenosis. Finally, in the entire study cohort, no clinically-driven DUS studies demonstrated iatrogenic vascular injury or vessel thrombosis in the StarClose treated patients. CONCLUSION: DUS, a safe and reliable method for determining the safety and efficacy of access site closure devices, is a reliable, safe, inexpensive and accurate method of assessing vascular access site complications in multicenter trials. In this substudy of the CLIP study, DUS found no statistical difference in access site complications between the StarClose and manual compression groups. Both groups maintained vessel patency without stenosis, thrombosis, hematoma, pseudoaneurysm, or AV fistula.

Adult↗
PubMed2006

The StarClose Vascular Closure System: interventional results from the CLIP study.

BACKGROUND: The StarClose Vascular Closure System is a femoral access site closure technology that uses a flexible nitinol clip to complete a circumferential, extravascular arteriotomy close. The Clip CLosure In Percutaneous Procedures study was initiated to study the safety and efficacy of the StarClose device in subjects undergoing diagnostic and interventional catheterization procedures. METHODS: A total of 17 U.S. sites enrolled 596 subjects, with 483 subjects randomized at a 2:1 ratio to receive StarClose or standard compression of the arteriotomy after the percutaneous procedure. The study included roll-in (n = 113), diagnostic (n = 208), and interventional (n = 275) arms with a primary safety endpoint of major vascular complications through 30 days and a primary efficacy endpoint of postprocedure time to hemostasis. RESULTS: The results of the diagnostic StarClose cohort have been reported separately. Results for the interventional arm revealed major vascular complications occurring in 1.1% of StarClose subjects (2/184) and 1.1% in manual compression subjects (1/91; P = 1.00). No infections were seen in either cohort. Minor complications in the StarClose interventional group occurred at a rate of 4.3% (8/184) and with compression at 9.9% (9/91; P = 0.107). Pseudoaneurysm or arteriovenous fistula was not seen with StarClose. With StarClose, procedural success was 100% (136/136) for the diagnostic group and 98.9% (181/183) in the interventional group. Device success for the treatment group was 86.8%. In the interventional cohort, 87.3% (158/181) of StarClose subjects reported a pain scale of 0-3 compared with 93.3% (84/90) in the compression group, which was not statistically different. CONCLUSIONS: The clinical results of this study demonstrate that the StarClose Vascular Closure System is noninferior to manual compression with respect to the primary safety endpoint of major vascular events in subjects who undergo percutaneous interventional procedures. StarClose significantly reduced time to hemostasis, ambulation, and dischargeability when compared with compression.

Aged↗
PubMed2001

Behind armour blunt trauma--an emerging problem.

Behind Armour Blunt Trauma (BABT) is the non-penetrating injury resulting from the rapid deformation of armours covering the body. The deformation of the surface of an armour in contact with the body wall arises from the impact of a bullet or other projectile on its front face. The deformation is part of the retardation and energy absorbing process that captures the projectile. In extreme circumstances, the BABT may result in death, even though the projectile has not perforated the armour. An escalation of the available energy of bullets and the desire of armour designers to minimise the weight and bulk of personal armour systems will increase the risk of BABT in military and security forces personnel. In order to develop materials that can be interposed between the armour and the body wall to attenuate the transfer of energy into the body, it is essential that the mechanism of BABT is known. There is a great deal of activity within UK and NATO to unravel the interactions; the mechanism is likely to be a combination of stress (pressure) waves generated by the rapid initial motion of the rear of the armour, and shear deformation to viscera produced by gross deflection of the body wall. Physical and computer model systems are under development to characterise the biophysical processes and provide performance targets for materials to be placed between armours and the body wall in order to attenuate the injuries (trauma attenuating backings-TABs). The patho-physiological consequences of BABT are being clarified by research, but the injuries will have some of the features of blunt chest trauma observed in road traffic accidents and other forms of civilian blunt impact injury. The injuries also have characteristics of primary blast injury. An overview diagnosis and treatment is described.

Energy Transfer↗
PubMed2000

Directional coronary atherectomy in intermediate sized vessels: final results of the intermediate vessel atherectomy trial (IVAT).

Revascularization options for intermediate sized vessels (2.5-2.9 mm) have historically been limited. IVAT is a pilot study to assess the efficacy and safety of debulking intermediate sized vessels using directional coronary atherectomy (DCA). Between March 1996 and June 1997, 50 patients were enrolled at seven hospitals in the United States. Of those patients, 70% presented with unstable angina and 52% had single vessel disease. Of the lesions treated, 96% were de novo. Adjunctive PTCA after DCA was performed in 90% of cases at the discretion of the investigator to maximize luminal diameter. The GTO DCA device was used in 90% of cases. Procedural success (residual stenosis <50% without major complications) was 94%. Stents were placed in 12% of patients. The only complications were three non-Q wave MIs. Mean reference vessel diameter increased from 2.49 mm pre-procedure to 2.57 mm after DCA and 2.61 post-procedure; mean MLD increased from 0.76 mm to 2.03 mm to 2.31 mm; and mean stenosis decreased from 70% to 21% post DCA and to 11% post procedure. At six months follow-up, 18.0% of target lesions required revascularization. Total revascularization, including non-target vessels, was 32%. These results suggest that DCA has a high procedural success rate and a low target lesion revascularization rate in intermediate sized vessels.

Adult↗
PubMed1999

Heparin after percutaneous intervention (HAPI): a prospective multicenter randomized trial of three heparin regimens after successful coronary intervention.

OBJECTIVES: The purpose of this study was to determine the incidence of bleeding, vascular, and ischemic complications using three different heparin regimens after successful intervention. BACKGROUND: The ideal dose and duration of heparin infusion after successful coronary intervention is unknown. METHODS: Patients were randomized to one of three heparin strategies after coronary intervention: Group 1 (n = 157 patients) received prolonged (12 to 24 h) heparin infusion followed by sheath removal; Group 2 (n = 120 patients) underwent early removal of sheaths, followed by reinstitution of heparin infusion for 12 to 18 h; Group 3 (n = 137 patients) did not receive any further heparin after intervention with early sheath removal. The primary end point of the study was the combined incidence of in-hospital bleeding and vascular events. Secondary end points included in-hospital ischemic events, length of stay, cost and one-month outcome. RESULTS: After successful coronary intervention, 414 patients were randomized. Unstable angina or postinfarction angina was present in 83% of patients before intervention. The combined incidence of bleeding and vascular events was 21% in Group 1, 14% in Group 2 and 8% in Group 3 (p = 0.01). The overall incidence of in-hospital ischemic complications was 2.2%; there were no differences between groups. Length of hospital stay was shorter (p = 0.033) and adjusted hospital cost was lower (p < 0.001) for Group 3. At 30 days, the incidence of delayed cardiac and vascular events was similar for all three groups. CONCLUSIONS: Heparin infusion after successful coronary intervention is associated with more minor bleeding and vascular injury, prolonged length of stay and increased cost. In-hospital and one-month ischemic events rarely occur after successful intervention, irrespective of heparin use. Routine postprocedure heparin is not recommended, even in patients who present with unstable ischemic syndromes.

Angioplasty, Balloon, Coronary↗
PubMed1998

Studies of vaccination of persons in close contact with leprosy patients in Argentina.

A total of 670 adults living or working with leprosy patients, were examined for a BCG vaccination scar, and skin-tested with four new tuberculins. Based on the results 513 were vaccinated, 65 with Bacille de Calmette et Guérin (BCG) alone, 66 with BCG plus killed Mycobacterium vaccae and 382 with killed M. vaccae alone. Skin-testing was repeated 2-3 years later on 344 subjects, when all three vaccines were found to have been highly successful in increasing responses to Tuberculin and Leprosin A (p < 0.0005) with increased immune recognition of common and species-specific antigens. Mean diameters of induration to each skin-test were greatest in recipients of BCG alone (p < 0.05), which suggests that better immuno-regulation occurs after receiving vaccines that incorporate M. vaccae. The results suggest 10(8) M. vaccae alone might prove a valuable future vaccine, which would not require selective pre-vaccination procedures.

Adult↗
PubMed1993

Support for newly qualified entrants to the speech and language therapy profession. Implications for managers.

Reports on a survey of 1990 and 1991 graduates entering the speech and language therapy profession in the UK and on the experiences of six new therapists in one "good practice" area, Ayrshire and Arran Health Board. Results show that new therapists were given a great deal of help and support from professional managers, and valued it highly. They chose posts which offered a mixed client load and good induction packages. Pre-service training reflected work carried out in service, but all client groups had not been accessed during training. Issues relating to throughput and case-load management required most support. They made successful personal adaptations to the work environment, and managers found them effective overall. Calculates the costs of supporting new therapists. Highlights the need to maintain professional support and discusses the potential difficulties involved in doing so in relation to NHS reforms.

Adult↗
PubMed1993

Bovine myocardial epithelial inclusions.

Light microscopic, histochemical, immunohistochemical, and ultrastructural methods were used to examine myocardial epithelial masses in the hearts of ten cattle. The tissues consisted of paraffin-embedded or formalin-fixed samples from eight hearts that were being inspected in slaughter houses and from two hearts from calves that died of septicemia. The ages of the cattle ranged from 4 days to 12 years; the breeds were unspecified for all but one Hereford female and the two Holstein calves; and there were three males, four females, and three steers. The masses in these cases were compared with similar appearing lesions found in other animal species. The lesions in the bovine hearts were single to multiple, well circumscribed, found in the left ventricle wall, and composed of squamous to cuboidal epithelial cells that formed tubular, ductular, and acinar structures with lumens that were void or filled with amorphous protein globules. Electron microscopic examination revealed epithelial cells that had sparse apical microvilli, tight apical intercellular junctions, perinuclear bundles of filaments, and rare cilia. Almost half of the bovine epithelial masses (4/9) had occasional diastase-resistant periodic acid-Schiff-positive granules in their cytoplasm, and few had hyaluronidase-resistant alcian blue-positive granules (2/9) or colloidal iron-positive granules (1/9). All myocardial masses had abundant collagen surrounding the tubular and acinar structures, and 2/9 had elastin fibers as well. None of the myocardial masses had Churukian-Schenk or Fontana Masson's silver staining granules in epithelial cells. Immunohistochemically, all bovine myocardial tumors stained positively for cytokeratin (8/8), and occasional masses stained positively for vimentin (3/8) or carcinoembryonic antigen (3/8). None of the masses stained positively for desmin. The myocardial epithelial tumors most likely represent endodermal rests of tissue misplaced during organogenesis.

Animals↗
PubMed1991

The professional role for nurses in clinical trials.

This article has examined the role of the nurse in clinical trials, particularly the clinical, administrative, and research roles. Components of each role and characteristics essential for the implementation of each role have been examined. The nursing role in clinical trials research is undergoing major transformation from the perception of the nurse as a data collector for medical research to the recognition of the nurse as an essential member of the research team with a multifaceted role. Miaskowski identifies two factors influencing the development of oncology nursing practice; scientific and technological advances and societal factors relating to the perception of cancer as a disease and changes in the nursing profession. Certainly it is recognized that progress in basic science research will lead to an increase in the complexity and number of clinical trials. Nurses have clearly implemented the roles necessary to be vital participants and have contributed to answering questions leading to improved treatments for the patients with cancer.

Clinical Trials as Topic↗
PubMed1990

Course of HIV-I infection in a cohort of homosexual and bisexual men: an 11 year follow up study.

OBJECTIVE--To characterise the natural history of sexually transmitted HIV-I infection in homosexual and bisexual men. DESIGN--Cohort study. SETTING--San Francisco municipal sexually transmitted disease clinic. PATIENTS--Cohort included 6705 homosexual and bisexual men originally recruited from 1978 to 1980 for studies of sexually transmitted hepatitis B. This analysis is of 489 cohort members who were either HIV-I seropositive on entry into the cohort (n = 312) or seroconverted during the study period and had less than or equal to 24 months between the dates of their last seronegative and first seropositive specimens (n = 177). A subset of 442 of these men was examined in 1988 or 1989 or had been reported to have developed AIDS. MAIN OUTCOME MEASURES--Development of clinical signs and symptoms of HIV-I infection, including AIDS, AIDS related complex, asymptomatic generalised lymphadenopathy, and no signs or symptoms of infection. MEASUREMENTS AND MAIN RESULTS--Of the 422 men examined in 1988 or 1989 or reported as having AIDS, 341 had been infected from 1977 to 1980; 49% (167) of these men had died of AIDS, 10% (34) were alive with AIDS, 19% (65) had AIDS related complex, 3% (10) had asymptomatic generalised lymphadenopathy, and 19% (34) had no clinical signs or symptoms of HIV-I infection. Cumulative risk of AIDS by duration of HIV-I infection was analysed for all 489 men by the Kaplan-Meier method. Of these 489 men, 226 (46%) had been diagnosed as having AIDS. We estimated that 13% of cohort members will have developed AIDS within five years of seroconversion, 51% within 10 years, and 54% within 11.1 years. CONCLUSION--Our analysis confirming the importance of duration of infection to clinical state and the high risk of AIDS after infection underscores the importance of continuing efforts both to prevent transmission of HIV-I and to develop further treatments to slow or stall the progression of HIV-I infection to AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Condemnation of beef because of Sarcocystis hirsuta infection.

Carcasses from 18 Holstein cows from Nevada, California, and Oregon were condemned because of grossly visible sarcocysts of Sarcocystis hirsuta. Sarcocysts were white to dull white, 2 to 7 mm long, and approximately 1 mm wide. Sarcocysts were most numerous in muscles of diaphragm, flank, and limbs and were able to infect laboratory-raised cats.

Animals↗
PubMed1990

HIV seroconversion in two homosexual men after receptive oral intercourse with ejaculation: implications for counseling concerning safe sexual practices.

Seroconversion for HIV antibody occurred in two homosexual men who reported no anal intercourse for greater than or equal to 5 years and multiple episodes of receptive oral intercourse with ejaculation. Neither man reported intravenous drug use or receipt of blood products. The last antibody-negative specimen was also negative by the polymerase chain reaction and p24 antigen assays. All sexually active persons should be clearly counselled that receptive oral intercourse with ejaculation carries a potential risk of HIV transmission.

Adult↗
PubMed1990

Relationship between AIDS latency period and AIDS survival time in homosexual and bisexual men.

We identified 277 homosexual and bisexual men diagnosed with acquired immune deficiency syndrome (AIDS) whose estimated human immunodeficiency virus (HIV) seroconversion dates, ranging from 1977-85, could be well approximated. These men were from a cohort of 6,705 homosexual and bisexual men originally recruited for studies of sexually transmitted hepatitis B in San Francisco in 1978-80. We compared the time from HIV seroconversion to the initial disease diagnostic of AIDS (AIDS latency period) with the time from first AIDS diagnosis to death (AIDS survival time) and found no significant overall correlation between latency period and survival time. Both Kaplan-Meier and Cox proportional hazard stepwise analyses found the initial AIDS diagnosis to be significantly associated with latency period, with individuals first diagnosed with Kaposi's sarcoma (KS) having a shorter latency but longer survival than those first diagnosed with Pneumocystis carinii pneumonia (PCP) or other AIDS diagnoses. Individuals with KS tended to be diagnosed earlier in the epidemic compared to those with PCP and other non-KS diagnoses. The AIDS survival time was significantly associated with the initial AIDS diagnosis but not with the estimated year of seroconversion, the year of first AIDS diagnosis, age at seroconversion, or racial/ethnic group. The information presented here on the relationship between the AIDS latency period and survival times suggests a model for the pathogenesis of HIV infection in which there is continual deterioration of the immune system. The wider use of antiviral and prophylactic therapies both preceding and following a diagnosis of AIDS may change this model as both latency and survival times are improved.

Acquired Immunodeficiency Syndrome↗