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Biomedical subjects

Robin S Howard

Publications and source records attributed to Robin S Howard.

15 recordsLinked to original sources
PubMed2006

Anterior segment measurements using digital photography: a simple technique.

PURPOSE: The purpose of this study is to describe a simple method of measuring anterior segment lesions from digital slit lamp images and confirm reliability of the technique. METHODS: Ten reference photos were taken of a PD ruler, refocusing on the ruler for each photo. Using Adobe Photoshop, the number of pixels per millimeter squared (area) and 1 mm (linear) were recorded for each photo. An Excel spreadsheet was set up to convert pixels to millimeters and millimeters squared. Interrater reliability was determined by two observers who independently calculated the area of 69 epithelial defects. A Bland and Altman plot was used to demonstrate the agreement between the two doctors. RESULTS: Interrater reliability was excellent as measured by an intraclass correlation coefficient (ICC 2,1) = 0.99. From the Bland and Altman plot it was determined that in 95% of cases, the area of the epithelial defect measured by provider 2 may be as much as 1.17 mm less than or 1.09 mm greater than that measured by provider 1. CONCLUSION: This simple method, which allows accurate measurements from digital images using common off-the-shelf software, is a valuable tool for clinical documentation as well as for research purposes.

Anterior Eye Segment↗
PubMed2005

Non-invasive assessment of respiratory muscle strength in patients with previous poliomyelitis.

UNLABELLED: In patients with poliomyelitis, respiratory failure requiring ventilatory support may occur during the acute illness. Some patients continue to require long-term nocturnal ventilatory support; others are weaned but subsequently require support because of a late deterioration in ventilatory function. OBJECTIVES: To assess the sensitivity of sniff nasal inspiratory pressure (SNIP) to post-poliomyelitis respiratory muscle weakness and to assess the relationship between the respiratory muscle strength and the need for ventilatory support in patients with previous poliomyelitis (post-polio patients). METHODS: Respiratory muscle strength was measured in 50 post-polio patients. Tests included forced vital capacity (FVC), maximum inspiratory and expiratory pressures (MIP and MEP), and SNIP. RESULTS: Twenty-one patients used non-invasive nocturnal ventilatory support (NIV group) compared to 29 on no support (non-NIV group). The percentage predicted FVC was significantly lower in the NIV group compared to the non-NIV group (P=0.01). Similarly, the percentage predicted MIP was significantly lower in NIV group (P=0.007). Low SNIP values (both absolute value and percentage predicted) were associated with the need for ventilatory support (P<0.001). Of the patients requiring no support, those who had been ventilated during the acute episode of poliomyelitis had a significantly lower SNIP than those who had never been ventilated (P=0.04). CONCLUSIONS: Post-polio patients who are currently on nocturnal ventilation have significantly lower FVC, MIP and SNIP compared to currently non-ventilated patients. Non-ventilated patients who were ventilated during the acute episode of poliomyelitis have significantly weaker respiratory muscle strength than patients who were never ventilated. This study indicates that SNIP is more sensitive to post-polio respiratory muscle weakness than other non-invasive tests. Thus measurement of SNIP is a valuable tool for monitoring the progression of respiratory muscle weakness due to previous poliomyelitis and this can be applied to other neuromuscular disorders.

Acute Disease↗
PubMed2005

The effect of fourth-generation fluoroquinolones gatifloxacin and moxifloxacin on epithelial healing following photorefractive keratectomy.

PURPOSE: To compare the rate of epithelial healing following photorefractive keratectomy (PRK) with two commercially available fourth-generation fluoroquinolones, gatifloxacin (Zymar, Allergan, Irvine, California) and moxifloxacin (Vigamox, Alcon Laboratories, Fort Worth, Texas). DESIGN: Double-masked, randomized, prospective trial. METHODS: Thirty-five subjects received gatifloxacin in one eye and moxifloxacin in the fellow eye following PRK with a 9.0-mm epithelial defect. Patients were examined daily after surgery until the epithelium had healed completely in both eyes. Beginning on post-operative day 3, photos were taken and used to confirm epithelial healing or measure the area of residual epithelial defects. Healing times and defect sizes were compared using the Wilcoxon signed-ranks test. RESULTS: Both eyes healed on the same day in 18 of the 35 subjects (51.4%). In 13 of 35 (37.1%) subjects, the moxifloxacin-treated eye healed first, compared with only four of 35 (11.4%) subjects whose gatifloxacin-treated eye healed first. All six of the eyes that took 2 days longer than their fellow eye to heal were gatifloxacin-treated. Median healing time for both groups was 4 days (moxifloxacin range: 3 to 7 days; gatifloxacin range: 3 to 9 days; P = .01), but only 69% of gatifloxacin-treated eyes had healed by day 4 compared with 80% of the moxifloxacin-treated eyes. Overall, on each post-operative day, defect sizes were greater for the gatifloxacin-treated eyes. This difference was statistically significant on day 4 (P = .027). CONCLUSIONS: Eyes treated with moxifloxacin healed faster and had smaller defects compared with those treated with gatifloxacin. This provides another factor to consider in selecting antibiotic prophylaxis for corneal refractive surgery.

Adult↗
PubMed2005

Comparison of test devices for skin prick testing.

BACKGROUND: Allergy skin testing guides developing avoidance plans and writing an immunotherapy prescription. The goal for the allergist is to apply allergen skin testing to the appropriate patient population by using a device that minimizes both false-negative and false-positive findings while minimizing patient discomfort. New skin testing devices continue to be developed with a trend toward production of multiheaded devices. Data on the performance of these devices in a head-to-head prospective fashion are limited. OBJECTIVE: Our goal was to study 8 commonly used devices to compare their performance in a head-to-head fashion. METHODS: In a prospective, double-blind fashion, the performance of 8 skin test devices was evaluated. Devices were tested with histamine and saline on both the arms and back of each subject. Devices were rotated over 4 testing sessions, at least a week apart, so each device was tested in each anatomic testing location. Performance elements examined included wheal, flare, pain, sensitivity, specificity, and intradevice variability. RESULTS: We found significant differences in all areas of device performance among all devices examined. Multiheaded devices also demonstrated significant intradevice variability and were more painful than single devices. Furthermore, multiheaded devices had larger reactions on the back, whereas single devices had larger reactions on the arms. CONCLUSION: Statistically significant differences exist among all devices tested. Providers should consider this data when choosing a device that suits their practice setting and ensure that technicians are sufficiently trained on the correct use of that device.

Adult↗
PubMed2005

Linear increase in axial stiffness of regenerate callus during limb lengthening.

Distraction osteogenesis is a powerful tool for addressing segmental defects and limb-length discrepancies. Guidelines for the rate and rhythm of distraction have been described. The possibilities of early consolidation or nonunion threaten clinical success. A quantifiable method for monitoring the distraction gap would be useful. Previous methods to measure regenerate callus stiffness have not gained widespread clinical acceptance, largely because of cumbersome instrumentation. A rabbit tibial lengthening model was used to show the clinical utility of a digital torque wrench in monitoring axial stiffness of the regenerate bone callus during distraction osteogenesis. We confirmed the linear increase in peak torsional stiffness with time, which has been reported by others. This relationship may prove to be a useful clinical adjunct in guiding the rate and rhythm of distraction during limb lengthening.

Animals↗
PubMed2004

Long-term efficacy of BCG vaccine in American Indians and Alaska Natives: A 60-year follow-up study.

CONTEXT: The duration of protection from tuberculosis of BCG vaccines is not known. OBJECTIVE: To determine the long-term duration of protection of a BCG vaccine that was previously found to be efficacious. DESIGN: Retrospective record review using Indian Health Service records, tuberculosis registries, death certificates, and supplemental interviews with trial participants. SETTING AND PARTICIPANTS: Follow-up for the period 1948-1998 among American Indians and Alaska Natives who participated in a placebo-controlled BCG vaccine trial during 1935-1938 and who were still at risk of developing tuberculosis. Data from 1483 participants in the BCG vaccine group and 1309 in the placebo group were analyzed. MAIN OUTCOME MEASURES: Efficacy of BCG vaccine, calculated for each 10-year interval using a Cox regression model with time-dependent variables based on tuberculosis events occurring after December 31, 1947 (end of prospective case finding). RESULTS: The overall incidence of tuberculosis was 66 and 138 cases per 100 000 person-years in the BCG vaccine and placebo groups, respectively, for an estimate of vaccine efficacy of 52% (95% confidence interval, 27%-69%). Adjustments for age at vaccination, tribe, subsequent BCG vaccination, chronic medical illness, isoniazid use, and bacille Calmette-Guérin strain did not substantially affect vaccine efficacy. There was slight but not statistically significant waning of the efficacy of BCG vaccination over time, greater among men than women. CONCLUSION: In this trial, BCG vaccine efficacy persisted for 50 to 60 years, suggesting that a single dose of an effective BCG vaccine can have a long duration of protection.

BCG Vaccine↗
PubMed2004

Multiservice laparoscopic surgical training using the daVinci surgical system.

BACKGROUND: The daVinci surgical system affords surgeons a magnified three-dimensional videoscopic view of the operative field and precise articulating laparoscopic instruments. The learning curve for this advanced surgical robotics system is poorly characterized. METHODS: Twenty-three surgeons representing seven surgical subspecialties participated in a surgical robotics training program consisting of standardized daVinci system training (phase 1) followed by self-guided learning in a porcine model (phase 2). RESULTS: The average number of recorded procedures performed per surgeon during phase 2 was 5.5. The mean daVinci system set-up time was 45 minutes and decreased by an average of 56.1% by the third successive set-up (r = -0.702, P <0.005). Operative times decreased 39.0% by the third successive practice operation (r = -0.860, P <0.0005). CONCLUSIONS: New use of the daVinci robot is associated with a rapid learning curve and preclinical animal model training is effective in developing surgical robotics skills.

Animals↗
PubMed2002

Frequency and type of serious infections in fludarabine-refractory B-cell chronic lymphocytic leukemia and small lymphocytic lymphoma: implications for clinical trials in this patient population.

BACKGROUND: Treatments for fludarabine-refractory chronic lymphocytic leukemia (CLL)/small lymphocytic lymphoma (SLL) are limited. Most new therapies being examined in fludarabine-refractory patients have shown a high frequency of serious infection. Little data exist regarding the frequency of infections in this population treated with noninvestigational best supportive care therapies. METHODS: The infectious courses of 27 patients with fludarabine-refractory CLL/SLL were retrospectively reviewed. Fludarabine-refractoriness was defined as either relapse within six months of completion of or failure to respond to fludarabine treatment. Infections were documented after patients met National Cancer Institute criteria for further treatment. Serious infections were defined as infections mandating admission to the hospital for intravenous antibiotics. RESULTS: Patient characteristics included: median age 67 years (range, 40-83), median 3 chemotherapy treatments (range, 1-8), and hypogammaglobulinemia in 73% of patients. Pneumocystis carinii prophylaxis was given to 89% of patients. Serious infections developed in 24 out of 27 patients (89%). Patients had a median of 2 admissions (range, 0-11) for serious infection occurring at a median of 4 months (range, 0-21) from onset of fludarabine-refractoriness. The median frequency of admission for infection was 0.17 per month. Most common sites for infection in decreasing frequency were: respiratory tract, urinary tract, blood/sepsis, and soft tissues. Bacteria caused 69 out of 88 infections (78.4%); viruses (varicella-zoster and herpes simplex) caused 11 out of 88 (12.5%); fungi caused 4 out of 88 (4.5%); and opportunistic infections caused 4 out of 88 (4.5%). Median survival was 13.0 months (range, 1-44+). CONCLUSIONS: The frequency of serious infections in patients with fludarabine-refractory CLL/SLL is high. These findings are relevant to trials with new and highly effective agents for which the incidence of serious infections after treatment might otherwise appear to be prohibitively high.

Adult↗
PubMed2002

Homocysteine: a risk factor for retinal venous occlusive disease.

PURPOSE: Recent studies have shown a relationship between elevated levels of homocysteine and vascular disease including cerebrovascular accidents and myocardial infarctions. We evaluated patients with a recent retinal vein occlusion to determine if there was an associated elevation of homocysteine. DESIGN: Age and gender matched case-controlled study. PARTICIPANTS: Twenty patients with retinal venous occlusive disease within the previous 6-month period and 40 control patients without retinal venous occlusive disease were enrolled in the study. METHODS: Twenty patients with a history of retinal vein occlusion underwent laboratory testing to determine serum homocysteine levels. In addition, a health survey was completed and several laboratory tests relating to vascular disease including cholesterol were checked. Two control groups were selected. The first group included patients with diabetes and no history of retinal vascular occlusive disease. The second control group included nondiabetic patients who also had no prior history of retinal vascular occlusive disease. MAIN OUTCOME MEASURES: The main parameter measured in this study is fasting homocysteine. RESULTS: Fifteen of 20 patients (75%) with retinal vein occlusion disease had an elevated fasting serum homocysteine level, whereas only 5 of 40 control patients (13%) had an abnormal homocysteine level (P < 0.0005). CONCLUSIONS: Patients with retinal venous occlusive disease have higher levels of homocysteine, which may serve as a modifiable risk factor.

Adult↗
PubMed2002

A sleep disorders centre in the United Kingdom.

The demographic features of 296 patients who consulted a sleep disorders centre in the United Kingdom were reviewed. Diagnosis after a sleep study was mainly that of sleep-related breathing disorders; however, various other sleep disorders were also diagnosed. Considering that most sleep disorders are diagnosed only after sleep investigations, it should be emphasized that such a facility should be well prepared in undertaking not only polysomnography but also various sleep investigations, including multiple sleep latency testing and actigraphy. In addition, several treatment options, including sleep hygiene, light therapy, and behavioural therapy, should be available. Therefore, a sleep disorders centre needs to be operated by sleep specialists.

Adolescent↗