PubMed Health⌕ Search

Biomedical subjects

John A Ward

Publications and source records attributed to John A Ward.

At least 19 recordsLinked to original sources
PubMed2006

Impact of Acinetobacter infection on the mortality of burn patients.

BACKGROUND: Acinetobacter calcoaceticus-baumannii complex (Acb) is recognized as an important cause of nosocomial infections. Although Acb can be associated with multidrug resistance, its impact on mortality in burn patients has not been fully elucidated. STUDY DESIGN: In a retrospective cohort study assessing medical records and microbiology laboratory data at a US military tertiary care burn center, we evaluated all patients admitted to the burn center between January 2003 and November 2005. Data collected included age, severity of burn, comorbidities, length of stay, and survival to hospital discharge. In addition, microbiology data were reviewed to determine which patients were infected with Acb during this time frame. These data were then used to compare patients infected with Acb to patients not infected. Multivariate analysis using logistic regression was performed to determine which patient characteristics were associated with increased mortality. RESULTS: There were 802 patients included in the study. Fifty-nine patients met the case definition for infection. An additional 52 patients were found to be colonized with Acb. Patients with Acb infection had more severe burns and comorbidities, and had longer lengths of stay compared with patients without Acb or those with Acb colonization. Mortality in infected patients was higher compared with those without infection (relative risk = 2.86, p = 0.001). On multivariate analysis, infection with Acb was not statistically associated with mortality. CONCLUSIONS: Multidrug-resistant Acb is a common cause of nosocomial infection in the burn patient population. Despite this, it does not independently affect mortality.

Acinetobacter Infections↗
PubMed2006

Effect of adult strabismus on ratings of official U.S. Army photographs.

PURPOSE: To determine if strabismus affects the ratings of official U.S. Army photographs. METHODS: Photographs of seven women and seven men officers (subjects) were digitally altered to give the impression of strabismus. Four photographs of each subject were obtained: two in an orthotropic state; one in a left exotropic state; and one in a left esotropic state. The photographs were presented randomly to a panel of 38 raters. Masked to the study design, the raters rated every photograph on a 1 to 10 Likert scale. The results were grouped according to eye alignment: two orthotropic groups, one exotropic group, and one esotropic group. Comparisons of the mean ratings were made between each eye alignment group and based on the subject's gender. RESULTS: The mean rating for each orthotropic group was 5.4 and 5.5 Likert scale units with a SD of 0.8 and 0.9, respectively (group 1 and group 2). The mean rating for the exotropic group was 5.4 Likert scale units with a SD of 0.7. The mean rating for the esotropic group was 5.1 Likert scale units with a SD of 0.8. Significantly lower ratings were obtained for the esotropic group compared with the orthotropic group (p=0.028). Women received significantly lower ratings regardless of eye alignment (p=0.044). CONCLUSIONS: This study indicates that the presence of esotropia negatively affects the rating of an official U.S. Army photograph; furthermore, female gender negatively affects ratings.

Adult↗
PubMed2006

Radiographic indicators of ankle instability: changes with plantarflexion.

BACKGROUND: The effect of plantarflexion on radiographic indicators of instability was investigated in matched pairs of stable ankles and unstable ankle fractures with complete deltoid ligament tears to test the hypothesis that differences exist in indicators as a function of either stability or position. The purpose of this study was to determine whether plantarflexion increases radiographic indicators of ankle fracture instability. METHODS: Measurements from 34 patients scheduled for operative treatment of unstable ankle fractures were collected prospectively from normal, stable ankles and the injured, unstable ankles. Instability was defined as a positive fluoroscopic stress examination under anesthesia. Stability and instability and neutral position and plantarflexion were associated with eight radiographic indicators of which five were distances in millimeters and three were binomial (either stable or unstable). RESULTS: Measurements were larger in the unstable ankles than in the normal stable ankles. Plantarflexion was associated with increased distances in stable ankles, and a trend was seen in unstable ankles. Plantarflexion was associated with increased binomial indicators in unstable ankles but not in stable ankles. DISCUSSION: Joint positioning affected measurement of ankle stability: plantarflexion increased the sensitivity of radiographic indicators.

Ankle Injuries↗
PubMed2006

Waterproof versus cotton cast liners: a randomized, prospective comparison.

Casting injured extremities can cause complications (eg, itching, odor, rashes, skin maceration), many of which are associated with the inability to wash the extremity because of water retention and slow drying of conventional cast liners. A waterproof cast liner allows casts to become wet and perhaps improves hygiene and comfort. Fifty-nine patients (age, > or = 10 years) with upper or lower extremity injuries were randomized to a waterproof-liner group (n = 29) or a cotton-liner group (n = 30). Both groups had casts made of fiberglass tape. At each clinic visit, patients and physicians completed questionnaires evaluating comfort and skin condition, respectively. The waterproof-liner group had better scores for itch (P = .008), discomfort (P < .001), irritation (P = .002), overall patient score (P = .012), and overall physician score (P = .049).

Adolescent↗
PubMed2005

Measuring medical education and curriculum during orthopedic surgical residency.

BACKGROUND: Evaluating residency programs requires objective assessment tools, but few are readily available. The purpose of this study was to measure education by correlating resident test scores with several measurements of educator performance. MATERIALS AND METHODS: The study group included residents and educators from a single residency program. We performed a retrospective analysis of scores from the Orthopaedic In-Training Examination collected during a 6-year period. Resident examination scores were indexed by dividing program averages by national averages to determine yearly score trends and then were correlated with educator attendance and teaching hours. Subspecialty scores were ranked to gauge residency strengths and weaknesses. Teaching hours devoted to subspecialties were compared with test scores to measure curricular emphases and to appraise teaching efficiency. RESULTS: Yearly average examination scores were proportional to national averages (P < 0.001). However, of 3436 possible educator-score associations, only 15 scores correlated highly (r > 0.9) with educators, and only 26 were significant (P < 0.05). Trend analysis put subspecialty scores in yearly perspective. Ranking was inaccurate until scores were indexed to the national average. In 2002, the distribution of 238 teaching hours ranged from 4 to 48 h for subspecialties, and 9 of 12 subspecialties were emphasized disproportionately to the examination. Teaching efficiency varied more than 10-fold by subspecialty. CONCLUSIONS: The creation of a score index helped to identify and address imbalances between teaching hours devoted to subspecialties and resident needs as evidenced by low In-Training examination scores. The present study improved educator accountability by correlating measurements of teaching and learning.

Curriculum↗
PubMed2005

Epimysium and perimysium in suturing in skeletal muscle lacerations.

BACKGROUND: Direct muscle belly trauma is common. Selecting optimal methods for surgical repair of muscle disruption is difficult because reliable methods have not been established. Suturing tendon offers strong repairs, but epimysium and perimysium, the connective tissues that coalesce to form tendons, offer unknown repair strength. The purpose of this study was to compare biomechanical properties of repaired muscle in transected muscle bellies with epimysium and perimysium. METHODS: The authors surgically repaired with figure-eight stitches in both epimysium and perimysium groups. Individual stitches were placed in lacerated quadriceps bellies from a euthanized pig and were tensioned on a biomechanical machine. Maximum loads and strains were measured, and failure mechanisms were recorded. RESULTS: Loads and strains for repairs with epimysium were higher than those for repairs with perimysium. Failure mechanisms were significantly different between groups. CONCLUSION: These data showed that epimysium incorporation into suturing improves capacity to bear forces compared with perimysium incorporation.

Animals↗
PubMed2005

Use and limitations of magnetic resonance phase-contrast assessment of coronary flow reserve in a model of collateral dependence.

Phase-contrast magnetic resonance imaging (PC-MRI) is useful for assessing coronary artery flow reserves (CFR) in man and acute animal models with intermediate coronary lesions. The present study examines the use of PC-MRI for assessing CFR in a model with critical stenosis and collateral dependence. PC-MRI quantitative flow measurements from the proximal left anterior descending (LAD) and left circumflex (LCX) coronary arteries were compared with myocardial tissue perfusion reserve measurements (microsphere techniques) after placement of a 2.25-mm ameroid constrictor on the proximal LCX in a porcine model; measurements were obtained at implantation (n = 4) and at 3 to 4 weeks (n = 4) and 6 weeks (n = 5) postimplantation. CFR is defined as the ratio of maximal hyperemic flow to baseline flow. Hyperemia was induced using intravenous adenosine (140 mg/kg/min). Collateral dependence in the LCX distri bution was evidenced by angiographic findings of critical stenosis with minimal myocardial histological changes and normal baseline myocardial perfusion (microsphere techniques). In this setting, PC-MRI CFR was correlated with microsphere measures of perfusion reserve. Collateral dependence was confirmed by Evan's blue dye injection. This study provides angiographic, myocardial perfusion, and histological correlates associated with PC-MRI epicardial CFR changes during chronic, progressive coronary artery constriction. It also demonstrates the disparity between epicardial and myocardial measures of coronary flow reserve with collateral dependence and the caveats for PC-MRI use in models of progressive coronary constriction.

Adenosine↗
PubMed2004

Calcium chloride before i.v. diltiazem in the management of atrial fibrillation.

Diltiazem is commonly used to treat atrial fibrillation or flutter (AFF) with rapid ventricular response (RVR). Although it is very effective for rate control, up to an 18% prevalence of reported diltiazem-induced hypotension [defined by systolic blood pressure (SBP) < 90 mm Hg], and a mean of 9.7% hypotension have been reported from several studies totaling over 450 patients. This hypotension may complicate therapy. Our objective was to determine if calcium chloride (CaCl(2)) pre-treatment would blunt a SBP drop after i.v. diltiazem, while allowing diltiazem to maintain its efficacy. A prospective, randomized, double-blind, placebo-controlled study was conducted. Seventy-eight patients with AFF and a ventricular rate of >/= 120 beats per minute were enrolled. Half received i.v. CaCl(2) pre-treatment; the other half received placebo. All patients then received i.v. diltiazem in a standard, weight-based dose. A second dose of CaCl(2) pre-treatment or placebo and diltiazem was given if clinically indicated for additional rate control. Both CaCl(2) and placebo pre-treatment groups had equal lowering of heart rate (p < 0.001). There were no adverse events in the calcium pre-treatment study arm. One patient in the placebo group became paradoxically more tachycardic and apneic after the diltiazem infusion. Although i.v. CaCl(2) seems to be equally safe compared to placebo as a pre-treatment in the management of AFF with RVR, we were unable to find a statistically significant blunting of SBP drop with CaCl(2) i.v. pre-treatment. Until further research determines a benefit exists, we cannot recommend i.v. CaCl(2) pre-treatment before diltiazem in the treatment of AFF with RVR.

Adult↗
PubMed2003

Hemorrhage-induced vascular hyporeactivity to norepinephrine in select vasculatures of rats and the roles of nitric oxide and endothelin.

Hemorrhage-induced vascular hyporeactivity to norepinephrine (NE) and the possible effector roles of nitric oxide (NO) and endothelin (ET) were investigated in different vascular beds of rats. Under urethane anesthesia, rats (n = 7 per group) were hemorrhaged to a mean arterial pressure (MAP) of 50 mm Hg for 60 min. A group of rats was pretreated with either NG-nitro-L-arginine methyl ester (10 mg/kg), an NO synthase inhibitor, or PD142893 (0.1 mg/kg), an ET receptor antagonist 15 min before the end of the hypotensive period. Operated, euvolemic rats served as controls. The responses of MAP and the blood flow of the superior mesenteric (SMA), celiac (CA), left renal (LRA), and left femoral arteries (LFA) to NE (3 microg/kg, i.v.) were measured at baseline (prehemorrhage), at the end of the hypotensive period (0 h), and at 1, 2, and 4 h after the end of the hypotensive period. The pressor responses to NE on MAP at 0, 1, 2, and 4 h in the 60-min hemorrhage groups were reduced to 45.9%, 37.8%, 29.2%, 18.4% of baseline pressor response, respectively. At these same times, the fall in blood flow in response to NE in SMA, CA, LRA, and LFA was significantly blunted (P < 0.01). This loss of responsiveness in CA and LFA was more severe than in SMA and LRA (P < 0.05-P < 0.01). Pretreatment with L-NAME or PD142893 significantly improved the pressor response of MAP and the blood flow responses of the four arteries to NE (P < 0.01). Hypotension at 50 mm Hg for 60 min resulted in an apparent loss of vascular reactivity to NE, and the four vasculatures studies were not affected to the same extent. In addition, NO and ET appear to contribute to the loss of vascular reactivity in different vasculatures in hemorrhagic shock.

Animals↗
PubMed2003

Effects of crystalloid and colloid resuscitation on hemorrhage-induced vascular hyporesponsiveness to norepinephrine in the rat.

BACKGROUND: We have shown previously that hemorrhagic hypotension is associated with a progressive development of vascular hyporeactivity to norepinephrine (NE). The present study investigated whether select crystalloid or colloid resuscitation fluids would ameliorate this effect. METHOD: Anesthetized male rats were hemorrhaged to and maintained at a mean arterial pressure (MAP) of 50 mm Hg for 60 minutes. Rats (n = 7 per group) were then resuscitated with lactated Ringer's (LR), 7.5% hypertonic saline (HS) for 1 hour followed by LR (HS-LR), Hespan, or Hextend to restore and maintain MAP to 70 mm Hg over 4 hours. Additional hemorrhaged groups were resuscitated with LR to the baseline MAP (LR-BL) or received no resuscitation. A sham hemorrhage group served as controls. The responses of MAP and the blood flow of the superior mesenteric, celiac, left renal, and left femoral arteries to NE (3 microg/kg administered intravenously) were measured at BL (prehemorrhage); at the end of the hypotensive period; and at 1, 2, and 4 hours after resuscitation. RESULTS: Hemorrhagic hypotension significantly (p < 0.01) reduced the NE-induced pressor response in MAP and significantly reduced the contractile responses (reflected by the reduction of blood flow after NE administration) of the four arteries to NE. Hespan and Hextend infusion improved the NE response of MAP and the contractile responses of the observed arteries to NE significantly better than LR, HS-LR, or LR-BL. The colloids improved the vascular contractile responses to NE in the superior mesenteric and left femoral arteries and the pressor response of MAP to NE, to 80% to 90% of their basal response level compared with 40% to 60% with the crystalloid fluids (p < 0.05). LR-BL infusion resulted in hemodilution, with no added benefit to vascular responsiveness. CONCLUSION: These data suggest that hypotensive resuscitation to 70 mm Hg with colloids was better than crystalloids in improving vascular responsiveness to the pressor effects of NE and required smaller volumes. Normotensive resuscitation with LR was not better than hypotensive resuscitation. Not all vasculatures improved equally after fluid resuscitation.

Animals↗
PubMed2003

Lymphocyte modulation in a baboon model of immunosenescence.

The age-related modulation of lymphocyte number and function was assessed in a nonhuman primate model consisting of healthy olive baboons (Papio cynocephalus anubis) of ages encompassing the entire life span of this species. The objectives of this study were to characterize an animal model of immunosenescence and to assess whether or not age should be considered when designing studies for the evaluation of vaccine candidates in baboons. Specifically the following parameters were assessed in baboons from 6 months to 26 years of age: relative numbers of B lymphocytes, CD4+ and CD8+ T lymphocytes, and T lymphocytes expressing CD28, CD25, and phytohemagglutinin-stimulated lymphoproliferative activity; and concentrations of total immunoglobulin, soluble interleukin-2 receptor alpha, and soluble CD30 in serum. There was a statistically significant effect of age on lymphocyte numbers. As age increased, relative B-cell numbers (ranging from 6 to 50%) decreased (P < 0.001) and relative T-cell numbers (ranging from 28 to 80%) increased (P < 0.001). The increase in T-cell numbers involved both the CD4+ and CD8+ subsets. In addition, there was a significant negative correlation of age with levels of soluble interleukin-2 receptor alpha in serum. Modulation of lymphocyte numbers appears to occur gradually during the entire baboon life span, thus suggesting the presence of an age-related developmentally regulated process. These findings indicate that baboons represent a potentially useful model to study selected phenomena related to immunosenescence. These findings also indicate that, when using the baboon model for vaccine or other experimental protocols requiring the assessment of immune responses, it would be appropriate to take into account the age of the animals in the study design.

Aging↗
PubMed2003

Use of hair products containing hormone or placenta by US military personnel.

We surveyed 2,097 subjects stationed at a US Army School to study the use of commercial hair products whose labeled ingredients included hormone or placenta. Use of some of these products is associated with premature sexual development. Use by demographics is: All = 14.8%, whites = 6.3%, non-whites = 27.0%; males = 8.7%, females = 24.6%; officers = 7.3%, enlisted = 18.7%. Frequency of use was highest among non-white female enlisted personnel (43 +/- 6.4%) and lowest among white male commissioned officers (2.0 +/- 1.7%). Regardless of ethnicity, 13.4% of respondents' children used the hair product. Use is about four times higher for non-whites than for whites. Females and enlisted personnel are more likely to use the hair product than males or officers. The use of hormonal hair products among children parallels use by their parents. In spite of federal regulation, the use of these hair products is still common.

Adult↗
PubMed2002

Outpatient anterior urethroplasty: outcome analysis and patient selection criteria.

PURPOSE: We compared the outcomes of anterior urethroplasty for stricture disease performed on an outpatient and an inpatient basis. MATERIALS AND METHODS: We reviewed the records of 78, 1-stage anterior urethroplasties performed via excision with primary anastomosis, buccal mucosal graft or penile fasciocutaneous skin flap techniques from September 1997 to December 2000 by a single surgeon (A. F. M.). All patients had more than 1 year of followup (range 1 to 4.5). Of the graft procedures only those in the bulbar urethra were included in analysis. Outpatient procedures were defined as those in which the patient was discharged home within 24 hours. Clinical outcome was considered a failure when instrumentation was required postoperatively. RESULTS: Of the 78 anterior urethral repairs 54 (69%) were performed on an outpatient basis, including 50 (93%) in which the outcome was successful compared with 88% (21) of the 24 inpatient procedures. Excision with primary anastomosis had the highest outpatient rate (28 of 31 patients or 90%), followed by penile skin flaps (16 of 25 or 64%) and buccal mucosal grafts (10 of 22 or 45%). Patient characteristics were significantly associated with outpatient procedures, including younger mean age (36 versus 46 years), shorter mean stricture length (3.1 versus 6.6 cm.) and shorter mean operative time (3.2 versus 4.66 hours) (p <0.05). CONCLUSIONS: Anterior urethral reconstruction can often be completed safely and effectively on an outpatient basis.

Adolescent↗
PubMed2002

Unenhanced helical CT scanning of the abdomen and pelvis changes disposition of patients presenting to the emergency department with possible acute appendicitis.

This study sought to determine if obtaining an unenhanced abdominopelvic computed tomography (UHCT) scan alters the disposition of patients presenting to the Emergency Department (ED) with signs and symptoms of acute appendicitis. A convenience sample of 101 patients presenting with a clinical picture suggestive of appendicitis were prospectively enrolled. Emergency physicians (EPs) and general surgeons independently recorded their anticipated disposition of each patient as: discharge, admit for observation, or admit for appendectomy. A UHCT scan was then obtained and the patient's ultimate disposition recorded. EPs altered their dispositions after UHCT scanning in 35 patients (34.7%, 95% CI 25.4% to 44.0%), and general surgeons altered their dispositions in 27 patients (26.7%, 95% CI 18.1% to 35.3%). More patients underwent operative intervention than were originally selected by EPs [14 additional patients, (13.9%, 95% CI 7.1% to 20.6%)] or by surgeons [20 additional patients, (19.8%, 95% CI 12.0% to 27.6%)]. CT scan revealed alternative diagnoses in 20 patients (19.8%). UHCT scanning significantly alters patient disposition, and significantly increases the number of operative interventions performed in patients with suspected appendicitis. UHCT scanning may also identify alternate pathology that clinically mimics appendicitis.

Acute Disease↗
PubMed2002

Validation of the Diesse Mini-Ves erythrocyte sedimentation rate (ESR) analyzer using the Westergren ESR method in patients with systemic inflammatory conditions.

The Diesse Mini-Ves (DMV) erythrocyte sedimentation rate (ESR) analyzer was designed to improve efficiency in determining the ESR. We compared the Westergren ESR method with the 4-sample DMV ESR analyzer for performance and clinical correlation. This prospective observational study, conducted at a 450-bed tertiary medical center, evaluated 291 paired samples from subjects with various systemic inflammatory conditions. Linear regression analysis revealed a statistically significant correlation between the 2 methods. Satisfactory precision of the DMV analyzer was obtained for high and mid-range ESR values. The 4-sample DMV ESR analyzer was precise and comparable in results to the Westergren ESR method. This DMV ESR analyzer is now used at our medical center based on quality control improvements that include a faster, safer, and more standardized ESR method. Hospital or office-based clinical laboratories should consider using the 4-sample DMV ESR analyzer in place of the Westergren method.

Adult↗
PubMed2002

Herpes B virus-specific pathogen-free breeding colonies of macaques: serologic test results and the B-virus status of the macaque.

The demand by the biomedical research community for B virus-free macaques is growing. The availability of B virus-free macaques has never been greater but still falls short of the current demand. Providing resources depends on the definitions of a specific pathogen-free (SPF) macaque, a B virus-free macaque, and a serologically negative macaque. Many colony managers define a B virus-free macaque in light of the serologic status of the breeding colony, because virus identification is a more complex issue. The lack of a standardized definition of a B virus-free macaque is compounded by the fact that all assays inherently result in some false antibody-positive or -negative data, and reconciliation is equivocal. Long-term follow-up of a colony in which elimination of B virus is actively being attempted will necessarily result in a relatively small sample within the population being incorrectly categorized with regard to antibody status. The goal of this study was to determine whether serially collected serologic data demonstrated patterns that could be used to predict whether an animal was genuinely in the process of B virus antibody seroconversion. The best indication of seroconversion was an ELISA titer of > 1:500 or a positive result on a confirmatory test. Patterns of seroreactivity are more useful in identifying B virus-positive macaques during the screening phase of SPF colony development than during the maintenance phase.

Algorithms↗
PubMedDate not supplied

Passive biomechanical properties of sutured mammalian muscle lacerations.

Muscle trauma, such as laceration or transection, is a common occurrence, but repairing delicate tissue poses a clinical challenge. This is at least partially due to the lack of established muscle repair models. The purpose of this study was to compare the biomechanical properties of stitches in transected porcine and bovine muscle bellies. A biomechanical protocol was designed for measuring suture performance in muscle belly lacerations. Twenty simple stitches in porcine and 21 stitches in bovine specimens were tested. Individual stitches were placed in lacerated muscle bellies and tensioned on a biomechanical tester (model 8521S, Instron Corporation, Canton, MA). The mean maximum load for porcine (22.0 N) and bovine (23.9 N)stitches was not significantly different (p = .48). The difference in mean strains at maximum load between porcine (9.70/%) and bovine(8.0%0/) groups was statistically significant (p = .004). Failure mechanisms were similar. One porcine stitch avulsed the muscle transversely,while 19 stitches tore out longitudinally. All 20 stitches tore out in bovine specimens. Sutured muscle was the weakest element in each test. The present study demonstrated that sutured muscles performed similarly for the two mammals regarding the parameters of maximum load and mechanism of failure. Regarding suturing of skeletal muscle lacerations, both mammalian models had similar biomechanical performance for maximum loads and failure mechanisms, while strain data differed. The stitch load magnitudes in this study approximate those required to successfully repair transected muscle. Knowledge introduced by this study fills a gap concerning muscle stitching relevant to clinical care.

Abdominal Muscles↗