Evaluation of oncology infusion pharmacy practices: A nationwide survey

PURPOSE

Oncology care continues to evolve at a rapid pace including provision of infusion-based care. There is currently a lack of robust metrics around oncology infusion centers and pharmacy practice. The workgroup completed a nationwide survey to learn about oncology-based infusion pharmacy services offered. The objective was to highlight consistent, measureable oncology-based infusion pharmacy metrics that will provide a foundation to describe overall productivity including emphasis on high patient-safety standards.

METHODS

A nationwide survey was developed via a workgroup within the Vizient Pharmacy Cancer Care Group beginning in April 2019 and conducted electronically via the Vizient Pharmacy Network from September to November 2020. The survey was designed to capture a number of key metrics related to oncology-based infusion pharmacy services.

RESULTS

Forty-one sites responded to the survey. Responses highlighted hours of operation (median = 11.5), number of infusion chairs (median = 45). Staffing metrics included 7.1 pharmacist full-time equivalent (FTE) and 7.6 technician FTE per week. 80.5% of sites had cleanrooms and 95.1% reported both hazardous and nonhazardous compounding hoods. 68.3% of sites reported using intravenous (IV) technology, 50.0% measured turnaround time, and 31.4% prepared treatment medications in advance.

CONCLUSION

There was variability among oncology infusion pharmacy practices in regard to survey responses among sites. The survey results highlight the need for standardization of established productivity metrics across oncology infusion pharmacies in order to improve efficiency and contain costs in the changing oncology landscape. The survey provides insight into oncology infusion pharmacy practices nationwide and provides information for pharmacy leaders to help guide their practices.

Trocar site closure with a novel anchor-based (neoClose®) system versus standard suture closure: A prospective randomized controlled trial

Objective

Patients with obesity have a higher risk of trocar site hernia. The objective of the present study was to compare a standard suture passer versus the neoClose® device for port site fascial closure in patients with obesity undergoing laparoscopic bariatric surgery.

Methods

This is a randomized, controlled trial with two parallel arms. Thirty five patients with BMI ≥ 35 kg/m2 and undergoing laparoscopic sleeve gastrectomy or Roux-en-Y gastric bypass were randomized to each group. Port site fascial closure for trocars ≥ 10 mm was performed with the neoClose® device in the study group and the standard suture passer in the control group. Primary outcomes were time required to complete closure and intensity of postoperative pain at the fascial closure sites. Secondary outcomes were intraabdominal needle depth and incidence of trocar site hernia.

Results

The use of the neoClose® device resulted in shorter closure times (20.2 vs 30.0 s, p = 0.0002), less pain (0.3 vs 0.9, p = 0.002) at port closure sites, and decreased needle depth (3.3 cm vs 5.2 cm, p < 0.0001) compared to the standard suture passer. There was no trocar site hernia at the one-year follow-up in either group.

Conclusion

Use of the neoClose® device resulted in faster fascial closure times, decreased intraoperative needle depth, and decreased postoperative abdominal pain at 1 week as compared to the standard suture passer. These data need to be confirmed on larger cohorts of patients with longer follow-up, especially in terms of long-term hernia recurrence rates.

Extraskeletal Calcifications in Hutchinson-Gilford Progeria Syndrome

PURPOSE

Children with Hutchinson-Gilford progeria syndrome (HGPS), a rare premature aging disease, exhibit extraskeletal calcifications detected by radiographic analysis and on physical examination. The aim of this study was to describe the natural history and pathophysiology of these abnormal calcifications in HGPS, and to determine whether medications and/or supplements tested in clinical trials alter their development.

METHODS

Children from two successive clinical trials administering 1) lonafarnib (n = 26) and 2) lonafarnib + pravastatin + zoledronic acid (n = 37) were studied at baseline (pre-therapy), one year on therapy, and at end-of-therapy (3.3-4.3 years after the baseline visit). Calcium supplementation (oral calcium carbonate) was administered during the first year of the second trial and was subsequently discontinued. Information on calcifications was obtained from physical examinations, radiographs, and serum and urinary biochemical measures. The mineral content of two skin-derived calcifications was determined by x-ray diffraction.

RESULTS

Extraskeletal calcifications were detected radiographically in 12/39 (31%) patients at baseline. The odds of exhibiting calcifications increased with age (p = 0.045). The odds were unaffected by receipt of lonafarnib, pravastatin, and zoledronate therapies. However, administration of calcium carbonate supplementation, in conjunction with all three therapeutic agents, significantly increased the odds of developing calcifications (p = 0.009), with the odds plateauing after the supplement's discontinuation. Composition analysis of calcinosis cutis showed hydroxyapatite similar to bone. Although serum calcium, phosphorus, and parathyroid hormone (PTH) were within normal limits at baseline and on-therapy, PTH increased significantly after lonafarnib initiation (p < 0.001). Both the urinary calcium/creatinine ratio and tubular reabsorption of phosphate (TRP) were elevated at baseline in 22/39 (56%) and 31/37 (84%) evaluable patients, respectively, with no significant changes while on-therapy. The mean calcium × phosphorus product (Ca × Pi) was within normal limits, but plasma magnesium decreased over both clinical trials. Fibroblast growth factor 23 (FGF23) was lower compared to age-matched controls (p = 0.03).

CONCLUSIONS

Extraskeletal calcifications increased with age in children with HGPS and were composed of hydroxyapatite. The urinary calcium/creatinine ratio and TRP were elevated for age while FGF23 was decreased. Magnesium decreased and PTH increased after lonafarnib therapy which may alter the ability to mobilize calcium. These findings demonstrate that children with HGPS with normal renal function and an unremarkable Ca × Pi develop extraskeletal calcifications by an unidentified mechanism that may involve decreased plasma magnesium and FGF23. Calcium carbonate accelerated their development and is, therefore, not recommended for routine supplementation in these children.

Fluoroscopic imaging overestimates the screw tip to subchondral bone distance in a cadaveric model of slipped capital femoral epiphysis

PURPOSE

Intra-operative imaging plays a key role in screw placement for slipped capital femoral epiphysis (SCFE). Complications have been associated with inadequate screw position. The purpose of this study was to evaluate computed tomography (CT) (3D fluoroscopy) and standard fluoroscopy (C-arm) images as compared with direct anatomic measurement to determine final screw position in a cadaveric SCFE model.

METHODS

Osteotomy with pinning was performed at the physeal scar in ten cadaveric hips. A standardised approach-withdrawal technique was performed with C-arm images taken at 15° increments. We also obtained a CT (3D fluoroscopy) scan of each hip. The screw tip-subchondral bone (STSB) distance was measured on digital imaging software and also with a digital calliper directly when the femoral head was cut in plane to expose the STSB distance anatomically. Statistical analysis included t-tests and Fisher's exact test.

RESULTS

Moderate SCFE osteotomies were achieved with a mean Southwick angle (39.5° ± 7°). The 60° fluoroscopic image was found to be the most representative image (41% of the time) compared with both anteroposterior (AP) and lateral images (8% and 21%). Both fluoroscopy (2.7 ± 0.8 mm, p < 0.001) and CT (1.6 ± 0.7 mm, p = 0.03) overestimated the STSB distance compared with direct measurement (0.94 ±  0.51 mm). Two-thirds (67%) of CT measurements were within 1 mm of the cadaveric measurement, while only 20% of C-arm measurements fulfilled this criterion (p = 0.04).

CONCLUSIONS

Both standard fluoroscopy and CT overestimated the STSB distance when compared with direct measurement in a cadaveric model of SCFE. Surgeons should be aware of the limitations of intra-operative imaging to determine the STSB distance. We suggest that using the known pitch of a screw (2.9 mm in a 7.3-mm cannulated screw) as an intra-operative tool to help guide screw placement.

Multilingual Part-of-Speech Tagging: Two Unsupervised Approaches

We demonstrate the effectiveness of multilingual learning for unsupervised part-of-speech tagging. The central assumption of our work is that by combining cues from multiple languages, the structure of each becomes more apparent. We consider two ways of applying this intuition to the problem of unsupervised part-of-speech tagging: a model that directly merges tag structures for a pair of languages into a single sequence and a second model which instead incorporates multilingual context using latent variables. Both approaches are formulated as hierarchical Bayesian models, using Markov Chain Monte Carlo sampling techniques for inference. Our results demonstrate that by incorporating multilingual evidence we can achieve impressive performance gains across a range of scenarios. We also found that performance improves steadily as the number of available languages increases.

Relative value of sliding-thin-slab multiplanar reformations and sliding-thin-slab maximum intensity projections as reformatting techniques in multisection CT angiography of the cervicocranial vessels

BACKGROUND AND PURPOSE

To investigate image quality and vascular delineation of multisection CT (MSCT) angiography of the cervicocranial vessels with sliding-thin-slab (STS) maximum intensity projections (MIP) and multiplanar reformations (MPR).

MATERIALS AND METHODS

Ten patients examined with a standardized protocol on a 16-section MSCT were included in the study. The data were reformatted as MIP and MPR in 3 planes for each subject; both reformatting techniques were applied in an STS technique with an increment of 3 mm. Images were evaluated independently by 3 blinded readers grading image quality parameters and vascular delineation of supra-aortic arteries and veins. An extension of the Mantel-Haenzel row mean score test was used to compare the distribution of scores for vascular delineation and image quality between STS MIP and STS MPR.

RESULTS

STS MIP reformations were significantly superior to STS MPR in the delineation of all extra- and intracranial arteries and arterial segments and in the delineation of the cavernous sinus and the internal cerebral veins (P < .05). No significant differences were found for the large venous vessels, the visual assessment of vascular contrast, or the impact of imaging artifacts.

CONCLUSION

Because STS MIP reformations were preferred to or equal to STS MPR in all aspects, we recommend STS MIP as the primary reformatting technique in MSCT angiography of the cervicocranial vessels in addition to viewing the source images.

Classification of orbital floor fractures

A retrospective series of orbital, axial, and coronal computed tomography scans from 24 orbital floor fractures was studied to define the anatomic location of the fracture. Floor fractures without rim involvement, which are referred to clinically as blowout fractures, were located medial to the infraorbital nerve or extended on both sides of the nerve. Floor fractures with rim involvement were associated with zygomatico-orbital or Le Fort II or III fractures, and were located either lateral to or on both sides of the infraorbital nerve. No blowout fractures were confined to the lateral half of the orbital floor and no floor fractures with rim involvement were confined to the medial half of the orbital floor. The authors propose a classification system for describing orbital floor fractures based on their anatomic location relative to the infraorbital nerve.

Sensitivity of a clinical examination to predict need for radiography in children with ankle injuries: a prospective study

BACKGROUND

Radiographs are ordered routinely for children with ankle trauma. We assessed the predictive value of a clinical examination to identify a predefined group of low-risk injuries, management of which would not be affected by absence of a radiograph. We aimed to show that no more than 1% of children with low-risk examinations (signs restricted to the distal fibula) would have high-risk fractures (all fractures except avulsion, buckle, and non-displaced Salter-Harris I and II fractures of the distal fibula), and to compare the potential reduction in radiography in children with low-risk examinations with that obtained by application of the Ottawa ankle rules (OAR).

METHODS

Standard clinical examinations and subsequent radiographs were prospectively and independently evaluated in two tertiary-care paediatric emergency departments in North America. Eligible participants were healthy children aged 3-16 years with acute ankle injuries. Sample size, negative and positive predictive values, sensitivity, and specificity were calculated. McNemar's test was used to compare differences in the potential reduction in radiographs between the low-risk examination and the OAR.

FINDINGS

607 children were enrolled; 581 (95.7%) received follow-up. None of the 381 children with low-risk examinations had a high-risk fracture (negative predictive value 100% [95% CI 99.2-100]; sensitivity 100% [93.3-100]). Radiographs could be omitted in 62.8% of children with low-risk examinations, compared with only 12.0% reduction obtained by application of the OAR (p<0.0001).

INTERPRETATION

A low-risk clinical examination in children with ankle injuries identifies 100% of high-risk diagnoses and may result in greater reduction of radiographic referrals than the OAR.

IMRT (intensity modulated radiation therapy): progress in technology and reimbursement

For a new treatment technology to become widely accepted in today's healthcare environment, the technology must not only be effective but also financially viable. Intensity modulated radiation therapy (IMRT), a technology that enables radiation oncologists to precisely target and attack cancerous tumors with higher doses of radiation using strategically positioned beams while minimizing collateral damage to healthy cells, now meets both criteria. With IMRT, radiation oncologists for the first time have obtained the ability to divide the treatment field covered by each beam angle into hundreds of segments as small as 2.5 mm by 5 mm. Using the adjustable leaves of an MLC to shape the beam and by controlling exposure times, physicians can deliver a different dose to each segment and therefore modulate dose intensity across the entire treatment field. Development of optimal IMRT plans using conventional manual treatment planning methods would take days. To be clinically practical, IMRT required the development of "inverse treatment planning" software. With this software, a radiation oncologist can prescribe the ideal radiation dose for a specific tumor as well as maximum dose limits for surrounding healthy tissue. These numbers are entered into the treatment planning program which then calculates the optimal delivery approach that will best fit the oncologist's requirements. The radiation oncologist then reviews and approves the proposed treatment plan before it is initiated. The most recent advance in IMRT technology offers a "dynamic" mode or "sliding window" technique. In this more rapid delivery method, the beam remains on while the leaves of the collimator continually re-shape and move the beam aperture over the planned treatment area. This creates a moving beam that saturates the tumor volume with the desired radiation dose while leaving the surrounding healthy tissue in a protective shadow created by the leaves of the collimator. In the dynamic mode, an IMRT treatment session generally can be initiated and completed within the traditional 15-minute appointment window for radiation oncology clinics. In addition to being comforting for the patient, this rapid treatment delivery mode satisfies a key financial issue for hospitals and clinics by giving them the ability to handle high patient loads and achieve a more rapid return on their investment in an IMRT system. New IMRT reimbursement codes have been issued under the pass-through provisions of Medicare's Outpatient Prospective Payment System (OPPS), which authorize special or increased reimbursement levels for promising new developments in healthcare technology that previous reimbursement procedures did not address. These pass-through payments are generally applicable for defined periods during a promising new technology's early stage of adoption. In the case of codes G0174 and G0178, the effective period has been left open-ended. While the CMS adoption of these new IMRT reimbursement codes certainly paves the economic road for the diffusion of this technology by flattening out some of the economic obstacles, there are still bumps to overcome. The most obvious one is the investment in hardware and software that may be required. However, the added demands on staff and the cost of training cannot be ignored. IMRT is a treatment process involving FDA-approved medical devices, offering the hope of improved treatment outcomes with fewer complications for patients and higher reimbursement rates for hospital providers. By the end of the year 2001, there will probably be more than 75 hospitals with IMRT capabilities in place.

Reversal of tetraplegia in patients with cervical osteomyelitis--epidural abscess using anterior debridement and fusion

OBJECTIVE

Aggressive anterior debridement and fusion has been advocated for the treatment of cervical osteomyelitis/epidural abscess (COEA) for many years. In this study we review our experiences with severely neurologically impaired (tetraplegic) patients with COEA.

METHODS

From 1989-1999 we identified 20 cases of COEA treated with anterior debridement and fusion. Patients were identified from a prospectively maintained database. All inpatient and outpatient records were reviewed. Six patients were identified as being tetraplegic prior to surgery. Tetraplegia was defined as complete absence or only flicker movement of the extremities.

RESULTS

The age range was 41 to 74. There were five men and one woman. Anterior corpectomy and fusion with either iliac crest auto- or allograft was performed in all patients. In four of six patients an anterior cervical plate was utilized for internal fixation. Four of six patients were ambulatory at last follow-up.

CONCLUSION

Aggressive debridement and fusion in patients with COEA can result in successful outcomes even in patients who are tetraplegic prior to surgery.

The process and results of departmental specific safety surveys for health care organizations. Successful program

1. Meeting compliance and accreditation standards can be challenging for any organization, especially in the health care setting. Safety surveys can play a strategic role in proactively preparing for such events. 2. Implementing department specific safety surveys offers a tailored approach to monitoring and addressing the occupational safety issues that occur within each department. 3. Safety surveys are a method for assessing and monitoring the environment and employee training needs, and for driving safety decisions. 4. Safety in the workplace must be a shared and continuous responsibility among employees. A formal safety survey process instilling a culture of responsibility and "buy in" by all employees is necessary.

Persistent bacterial colonization of Porphyromonas gingivalis, Prevotella intermedia, and Actinobacillus actinomycetemcomitans in periodontitis and its association with alveolar bone loss after 6 months of therapy

BACKGROUND, AIMS

The purpose of this study was to determine whether the presence of bacterial antigens for Porphyromonas gingivalis (Pg), Prevotella intermedia (Pi), and Actinobacillus actinomycetemcomitans (Aa) in subgingival plaque of periodontitis patients after periodontal treatment was associated with progressive alveolar bone loss.

METHOD

39 (39) subjects in good general health previously diagnosed with adult periodontitis within the last 2 years, and still presenting with probing depth >5 mm in 2 to 6 teeth, were studied. All subjects were treated with scaling and root planing. Half of the subjects were randomly assigned to receive adjunctive systemic doxycycline (200 mg the 1st day, then 100 mg per day for 21 days). Subgingival plaque samples were taken at baseline, 1, 3 and 6 months after therapy. A modified ELISA test (Evalusite, Periodontal Test Kit, Eastman Kodak Co., Rochester, NY) was used to test for plaque antigens associated with P. gingivalis, P. intermedia and A. actinomycetemcomitans. Progressive alveolar bone loss was determined using digital subtraction radiography with standardized radiographs taken at baseline and 6 months after treatment.

RESULTS

The presence of P. gingivalis in plaque after treatment was significantly associated with progressive bone loss (positive predictive value 84%, negative predictive value 85%, odds ratio 31.9, p<0.0001). In contrast, the presence of P. intermedia in plaque after treatment was not indicative of progressive loss (positive predictive value 39%, negative predictive value 82%). Too few sites had evidence of A. actinomycetemcomitans to be amenable to statistical analysis. No significant difference in bone loss was attributable to the systemic antibiotic therapy.

CONCLUSION

These data indicated that, in this population, the presence of P. gingivalis in plaque after treatment might be indicative of progressive alveolar bone loss.

Aminosterols from the dogfish shark Squalus acanthias

Seven new aminosterols related to squalamine (8) were isolated from the liver of the dogfish shark Squalus acanthias. Their structures (1-7) were determined using spectroscopic methods, including 2D NMR and HRFABMS. These aminosterols possess a relatively invariant cholestane skeleton with a trans AB ring junction, a spermidine or spermine attached equatorially at C3, and a steroidal side-chain that may be sulfated. The structure of the lone spermine conjugate, 7 (MSI-1436), was confirmed by its synthesis from (5alpha,7alpha, 24R)-7-hydroxy-3-ketocholestan-24-yl sulfate. Some members of this family of aminosterols exhibit a broad spectrum of antimicrobial activity comparable to squalamine.

Institutional policies on the use of physical restraints on children

Within health care institutions, nursing policies often serve as the gold standard for nursing practice. Policies regarding the use of physical restraints on children are typically not based on any scientific evidence. This article analyzed multiple hospital policies and makes recommendations to better assess whether or not restraints are needed, suggests a list of least to most restrictive devices, identifies interventions for the child in restraints, and offers alternatives to the use of restraints.

Clinical and microbiological effects of subgingival antimicrobial irrigation with citric acid as evaluated by an enzyme immunoassay and culture analysis

The purpose of the present study was to compare an enzyme immunoassay with culture samples from untreated and non-surgically treated periodontal pockets and to assess the clinical and microbiological effects of citric acid irrigation as a supplement to scaling and root planing. The enzyme immunoassay used in this study is a chairside diagnostic tool aimed at identifying the presence of P. gingivalis, P. intermedia, and A. actinomycetemcomitans. Six sites with pocket depths > or = 6 mm in each of 16 patients were monitored for 24 weeks using clinical and microbiological parameters. In two out of the six sites, scaling and root planing was supplemented with subgingival citric acid irrigation of the pocket after completion of the mechanical treatment. The sensitivity of the immunoassay in relation to culture was calculated to 85.5% and the specificity to 90.2%. The immunoassay corresponded to a detection level of 10(4) as estimated by culture. Sites treated with a combination of scaling and irrigation with citric acid demonstrated a similar healing pattern as sites treated with scaling and root planing alone. The profile of the marker bacteria was almost parallel for the two groups. The results of this investigation thus indicated that the immunoassay can be used as a screening tool for selected periodontal pathogens and that adjunctive irrigation with citric acid has no measurable clinical or microbiological effects.

Spinal canal compromise in Proteus syndrome: case report and review of the literature

A 24-year-old Vietnamese man with Proteus syndrome presented to the emergency department with progressive paraplegia and underwent urgent operative decompression of an angiolipomatous mass compressing the spinal cord. The associated spinal deformity and difficulty in imaging the mass, together with the paucity of discussion regarding the spinal cord sequelae of this rare syndrome in the literature, made this an extremely challenging case. Spinal cord compromise in patients with Proteus syndrome can result from either infiltration of the spinal canal by an angiolipomatous mass or canal narrowing as a result of vertebral hypertrophy. Regardless of the cause, the prognosis for neural recovery remains poor.

Uses of and alternatives to restraints in pediatric settings

Restraints are a common component of pediatric nursing practice that currently have no empirical base. This article provides background information concerning the use of restraints with the pediatric population, the impact these devices have on children, and the possible alternatives that have been identified. It is hoped that by providing acute care nurses with recommendations concerning changes in this area of practice, the care that children receive in the inpatient setting may be improved.

Colonization by Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis and Prevotella intermedia in adult periodontitis patients as detected by the antibody-based Evalusite Test

Studies were performed to evaluate the detection of disease-associated bacterial colonization in adult periodontitis patients by the antibody-based Evalusite TestTM (Eastman Kodak Company). The association of test results with disease was assessed by collecting 104 duplicate subgingival plaque samples from 26 patients. Samples were tested for Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis and Prevotella intermedia using both microbiological culture and the immunoassay test. The sensitivity and specificity of the 2 methods was calculated using %s of positive results in deep periodontal pockets and negative results in shallow subgingival sites. A cutoff >10(4) cultivable counts yielded the greatest discrimination between health and disease on a cross-sectional basis and established this threshold as clinically relevant for the detection of disease-associated levels of bacterial colonization by these three microorganisms. The clinical detection limit of the immunoassay test was observed to coincide with this threshold of >10(4) cultivable counts. Microbiological testing of the 4 deepest pockets using the immunoassay test was determined to be sufficient to yield a 90% confidence of detecting positive patients in a study with 59 adult subjects. The immunoassay test method was also demonstrated to be effective at detecting bacterial colonization in sets of paper point samples that were pooled for analysis. An overall agreement of 94% (288 of 306) was observed when comparing test results for duplicate sets of pooled and individual samples collected from 51 patients. These studies demonstrate that the Evalusite Test is an effective method for detecting clinically relevant colonization by the test bacteria in patients at risk for periodontal disease.

Analytical performance of an immunologic-based periodontal bacterial test for simultaneous detection and differentiation of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, and Prevotella intermedia

The analytical performance of a membrane-based immunoassay for the simultaneous detection and differentiation of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, and Prevotella intermedia (including Prevotella nigrescens) was investigated. Positive reactions were observed for 71 of 71 reference strains and recent oral isolates of A. actinomycetemcomitans, P. gingivalis, and P. intermedia. No cross-reactivity was observed with 39 other common oral and environmental species. The specificity of the test was unaffected by the presence of potential oral interferents including whole blood, white blood cells, mucin, saliva, toothpastes, and oral rinses. A proficiency test by dental professionals using a standardized set of unknown simulated samples yielded a sensitivity of 97% (116/120) and a 100% specificity (240/ 240). An additional group including dental professionals and high school students was shown to be 99% proficient (1385/1397) in distinguishing proper from improper test function when processing control samples with normal test devices and devices with simulated error conditions. Comparisons to a culture standard for 104 subgingival plaque samples collected from 26 adult periodontitis patients yielded > 98% specificity for each of the test bacteria. In addition, the detection threshold for the test was determined to be equivalent to 10(4) cultivable test bacteria when compared to the culture standard. The data indicate that this membrane immunoassay is a valid and easy-to-use method for the detection of A. actinomycetemcomitans, P. gingivalis, and P. intermedia in subgingival plaque, at levels above the detection threshold of the test.

Oxidative damage to DNA in diabetes mellitus

BACKGROUND

Increased production of reactive oxygen species (ROS) and lipid peroxidation may contribute to vascular complications in diabetes. to test whether DNA is also oxidatively damaged in diabetes, we measured 8-hydroxydeoxyguanosine (8-OHdG), an indicator of oxidative damage of DNA, in mononuclear cells.

METHODS

For this laboratory-based study, 12 patients with insulin-dependent diabetes mellitus (IDDM) and 15 patients with non-insulin-dependent diabetes mellitus (NIDDM) were matched by age with ten healthy volunteers each. DNA was extracted from mononuclear cells from whole blood. 8-OHdG was assayed by high-pressure liquid chromatography, and ROS were assayed by chemiluminescence.

FINDINGS

IDDM and NIDDM patients had significantly higher median concentrations (p , 0.001, U test) of 8-OHdG in their mononuclear cells than their corresponding controls (in fmol/micrograms DNA): 128.2 (interquartile range 96.0-223.2) and 95.2 (64.0-133.5) vs 28.2 (21.7-43.4) and 21.9 (18.0-24.4), respectively. ROS generation by mononuclear cells was also significantly greater (p < 0.01) in diabetic patients than in their controls (in mV): 238.0 (107.0-243.0) and 101.3 (66.0-134.0) vs 69.5 (49.8-91.9) and 56.0 (38.8-62.5), respectively.

INTERPRETATION

IDDM and NIDDM patients showed greater oxidative damage to DNA, with increased generation of ROS, than controls. Such changes might contribute to accelerated aging and atherogenesis in diabetes and to the microangiopathic complications of the disease.

Nursing perceptions of using physical restraints on hospitalized children

PURPOSE

To describe the perceptions of pediatric nurses about restraint use in children.

METHOD

A descriptive survey using a questionnaire collected data from nurses working in four types of pediatric facilities. Nurses were asked to rate reasons for using restraints and alternatives to restraints on a Likert Scale. Analysis of variance analyzed the nurses' responses according to type of institution and age of the child. An open-ended question asked nurses to list reasons for using restraints.

RESULTS

Responses were collected from 60 nurses. There were significant differences in responses according to age of the child and according to the type of hospital. There were no interaction effects. The perceived need for restraints was highest between 1 and 6 years of age. Reasons for using restraints differed among types of facility.

CONCLUSIONS

Restraint policies may need to vary according to the type of institution. Intervention and outcome studies are needed regarding the use of physical restraints in children.

Vascular reactivity in patients with peripheral vascular disease

Noninvasive techniques have been used to demonstrate a specific pattern of impaired vasoactive response in the normal brachial artery of patients with clinical atherosclerosis. This is a physiologic reflection of the systemic nature of atherosclerosis and may be useful as a marker for identifying patients with preclinical atherosclerotic disease.

Ceruloplasmin levels in the human superior temporal gyrus in aging and Alzheimer's disease

In the present study we observed a loss in excess of 1/3 of the copper transport and anti-oxidant protein ceruloplasmin in both the gray and white matter from superior temporal gyrus in Alzheimer's diseased brains compared to age-matched controls. A decrease in ceruloplasmin could be reflected in decreased cellular metabolic processes such as the electron transport system and a decrease in the ability of the brain to protect itself from oxidative damage. Both decreased metabolic activity and an increase in oxidative insults are known to be associated with the neurological events in Alzheimer's disease, but the mechanism by which these phenomena occur are unknown. These results coupled with previous reports from this laboratory on iron regulatory proteins in the brain suggests one way in which cellular dysfunction and oxidative stress occurs in AD may be through a loss of ability to maintain a balance of essential metals.

Examination of the patient with a knee dislocation. The case for selective arteriography

One hundred fifteen patients with a unilateral knee dislocation underwent arteriography to examine the popliteal artery. The incidence of popliteal artery injury was 23% (27 patients). Clinically, 29 (25%) of the 115 patients had an abnormal ipsilateral pedal pulse and 23 (79%) of these 29 patients had an arteriographically identified popliteal artery injury. Twenty-two arteries were surgically repaired and one was treated without surgery. Eight-six patients had normal pulses; the arteriogram showed no abnormalities in 77, demonstrated spasm in five, and revealed an intimal flap in four. All 86 patients were treated without surgery and had no delayed vascular complications. This demonstrates that the vascular examination is an accurate predictor of major popliteal artery injury following knee dislocation. Patients with an abnormal pedal pulse warrant arteriography due to a high incidence (79%) of popliteal artery injury. Patients with normal pulses may be monitored by clinical examination only. Popliteal artery injuries in this group are minor and rarely require intervention.

A pictographic essay on blood and tissue oxygen transport

This review describes the transport of oxygen from ambient air to mitochondria in the cells. Using simple equations and diagrams, the presentation illustrates the variables which determine the magnitude of each of the three major steps in the partial pressure of O2 along the passage, from: (i) ambient air to alveolar gas; (ii) arterial blood to venous blood; and (iii) capillary blood to tissue. The emphasis is on steps (ii) and (iii), and how they are modified from the normoxic case by ischemia, anemia, hypoxia, and increased VO2. The basic context of step (iii) is the Krogh model. This model, despite its limitations, is proposed as conceptually useful in analyzing whole-body or tissue O2 transport.

Reversible and irreversible components of central-airway flow resistance

The flow energy loss (head loss) through a cast of canine central airways is found to be nearly independent of flow direction. By contrast, head loss in geometrically-simpler branching sections at comparable flow conditions is highly irreversible, with inspiratory loss being greater by nearly two units of dynamic pressure (2 X 1/2 rho V2). In these branching sections head loss appears to be independent of important geometric parameters such as the branch length/diameter ratio and the exit/inlet flow-area ratio. An analysis of these observations suggests that kinetic energy factors, not shear stresses, account for most of the energy dissipated in central airways and in simple bifurcating sections. Inspiratory loss in bifurcations is greatly increased by the onset of flow separation: irreversibility is minimal in central airways, where separation either is absent or else is much less pronounced.

Binding stoichiometry and structural mapping of the epsilon polypeptide of chloroplast coupling factor 1

Fluorescent probes were attached to the single sulfhydryl residue on the isolated epsilon polypeptide of chloroplast coupling factor 1 (CF1), and the modified polypeptide was reconstituted with the epsilon-deficient enzyme. A binding stoichiometry of one epsilon polypeptide per CF1 was obtained. This stoichiometry corresponded to a maximum inhibition of the Ca2+-dependent ATPase activity of the enzyme induced by epsilon removal. Resonance energy transfer between the modified epsilon polypeptide and fluorescent probes attached to various other sites on the enzyme allowed distance measurements between these sites and the epsilon polypeptide. The epsilon-sulfhydryl is nearly equidistant from both the disulfide (23 A) and the dark-accessible sulfhydryl (26 A) of the gamma subunit. Measurement of the distance between epsilon and the light-accessible gamma-sulfhydryl was not possible due to an apparent exclusion of modified epsilon from epsilon-deficient enzyme after modification of the light-accessible site. The distances measured between epsilon and the nucleotide binding sites on the enzyme were 62, 66, and 49 A for sites 1, 2, and 3, respectively. These measurements place the epsilon subunit in close physical proximity to the sulfhydryl-containing domains of the gamma subunit and approximately 40 A from the membrane surface. Enzyme activity measurements also indicated a close association between the epsilon and gamma subunits: epsilon removal caused a marked increase in accessibility of the gamma-disulfide bond to thiol reagents and exposed a trypsin-sensitive site on the gamma subunit. Either disulfide bond reduction or trypsin cleavage of gamma significantly enhanced the Ca2+-ATPase activity of the epsilon-deficient enzyme. Thus, the epsilon and gamma polypeptides of coupling factor 1 are closely linked, both physically and functionally.

Selective modification of an alpha subunit of chloroplast coupling factor 1

Lucifer yellow (4-amino-N-[3-(vinylsulfonyl)phenyl]naphthalimide-3,6-disulf onate), a fluorescent probe that can react covalently with sulfhydryl or amino groups, has been used to modify chloroplast coupling factor 1 (CF1). Conditions are described under which Lucifer yellow selectively labels the alpha subunit of CF1 to the extent of about 1 mol of probe per mole of CF1. An especially reactive amino group is apparently labeled, and modification has little effect on the ATPase activity of the enzyme. Lucifer yellow is a useful probe for fluorescence energy transfer measurements. The distances between this probe and fluorescent and absorbing molecules attached to seven specific sites on the beta, gamma, and epsilon subunits were determined. These distances converge to a single location. In addition to providing further information about the structure of CF1, these results suggest that the alpha subunits of CF1 are not structurally equivalent.

Structural organization of chloroplast coupling factor

Fluorescence resonance energy transfer measurements have been used to construct spatial maps for the accessible sulfhydryl of the gamma subunit (dark site) and the essential tyrosine residue of the beta subunits relative to previously mapped sites on the H+-ATPase from chloroplasts. The extent of energy transfer was measured between a coumarinylmaleimide derivative reacted covalently at the dark site and acceptor species selectively bound at the gamma-disulfide and the three nucleotide binding sites of the solubilized coupling factor complex. The nucleotide energy acceptor was 2'(3')-(trinitrophenyl)adenosine triphosphate, and the gamma-disulfide site was labeled with fluoresceinylmaleimide. The dark-site sulfhydryl also was labeled with pyrenylmaleimide which served as an energy donor for 7-chloro-4-nitro-2,1,3-benzoxadiazole reacted at the beta-tyrosine sites. Similar measurements were also made with pyrenylmaleimide covalently attached to the gamma-sulfhydryl accessible only under energized conditions on the thylakoid membrane surface (light site). The observed transfer efficiencies indicate that the dark-site sulfhydryl is approximately 45 A from all three nucleotide sites and 41-46 A from the gamma-disulfide site. The average distances separating the essential beta-tyrosines and the light- and dark-site sulfhydryls are 38 and 42 A, respectively. (In calculating these distances, random orientation of the donor-acceptor dipoles was assumed.) The results are consistent with a previously described structural model of the intact enzyme and can be used to gain insight into the overall structural organization or alpha-, beta-, and gamma-polypeptides within the coupling factor.

Structural mapping of chloroplast coupling factor

Fluorescence resonance energy transfer measurements have been used to investigate the spatial relationships between the nucleotide binding sites and the gamma-subunit of the H+-ATPase from chloroplasts and the orientation of these sites with respect to the membrane surface. Fluorescent maleimides reacted covalently at specific sulfhydryl sites on the gamma-subunit served as energy donors. One sulfhydryl site can be labeled only under energized conditions on the thylakoid membrane surface (light site). The two gamma-sulfhydryls exposed after catalytic activation served as a second donor site (disulfide site). In one set of experiments, the nucleotide analogue 2'(3')-(trinitrophenyl)adenosine triphosphate, selectively bound at each of the three nucleotide binding sites of the solubilized coupling factor, was used as an energy acceptor; in another, octadecylrhodamine with its acyl chain inserted in the vesicle bilayer and the rhodamine fluorophore exposed along the membrane surface was the energy acceptor. The distance between the sulfhydryl and disulfide sites was also obtained by sequentially labeling the sites with coumarin (donor) and fluorescein (acceptor) maleimide derivatives, respectively. The results indicate that all three nucleotide sites are approximately equal to 50 A from the light-labeled gamma-sulfhydryl. Two of the nucleotide sites are very far from the gamma-disulfide (greater than 74 A), while the third site, which binds nucleotides reversibly under all conditions, is 62 A from this sulfhydryl. The light-labeled sulfhydryl and disulfide sites are about 42-47 A apart. Finally, the distance of closest approach between the membrane surface of the reconstituted system and the gamma-disulfide is 31 A.(ABSTRACT TRUNCATED AT 250 WORDS)

A pulsed wire probe for the measurement of velocity and flow direction in slowly moving air

This report describes the theory and operation of a pulsed-probe anemometer designed to measure steady three-dimensional velocity fields typical of pulmonary tracheo-bronchial airflows. Local velocities are determined by measuring the transport time and orientation of a thermal pulse initiated at an upstream wire and sensed at a downstream wire. The transport time is a reproducible function of velocity and the probe wire spacing, as verified by a theoretical model of convective heat transfer. When calibrated the anemometer yields measurements of velocity accurate to +/- 5 percent and resolves flow direction to within 1 deg at airspeeds greater than or equal to 10 cm/s. Spatial resolution is +/- 0.5 mm. Measured flow patterns typical of curved circular pipes are included as examples of its application.

Lobar flow patterns in a hollow cast of canine central airways

To demonstrate that the regional partitioning of flow in central airways is direction dependent, we compared inspiratory and expiratory lobar flows in a hollow rigid cast of canine lungs. Lobar flows were measured by a hot-wire anemometer, simultaneous tracheal flows by a pneumotachograph, and data displayed as (lobar) flow-(tracheal) flow curves. For tracheal airflows between 50 and 370 ml/s, we found that inspiratory apical flows were smaller, and basal flows larger, than corresponding expiratory distributions. This effect was largely extinguished by substituting a gas mixture of 85% He-15% N2; resulting regional flows were comparable to expiratory distributions obtained on room air. Thus canine central airways structure induces a kinematically irreversible flow pattern, consistent with a model of "cascade flow" in which branching structure modifies the distribution only of inspiratory flow. These results support Fowler's concept that lung regions fill and empty sequentially and may be pertinent to analyses of regional washout.

Fluorescence energy transfer in two dimensions. A numeric solution for random and nonrandom distributions

A method of Monte Carlo calculations has been applied to the problem of fluorescence energy transfer in two dimensions in order to provide a quantitative measure of the effects of nonideal mixing of lipid and protein molecules on the quenching profiles of membrane systems. These numerical techniques permit the formulation of a detailed set of equations that describes in a precise manner the quenching and depolarization properties of planar donor-acceptor distributions as a function of specific spectroscopic and organizational parameters. Because of the exact nature of the present numeric method, these results are used to evaluate critically the validity of previous approximate treatments existing in the literature. This method is also used to examine the effects of excluded volume interactions and distinct lattice structures on the expected transfer efficiencies. As a specific application, representative quenching profiles for protein-lipid mixtures, in which donor groups are covalently linked to the protein molecules and acceptor species are randomly distributed within lipid domains, have been obtained. It is found that the existence of phase-separated protein domains gives rise to a shielding effect that significantly decreases the transfer efficiencies with respect to those expected for an ideal distribution of protein molecules. The results from the present numerical study indicate that the experimental application of fluorescence energy transfer measurements in multicomponent membrane systems can be used to obtain organizational parameters that accurately reflect the lateral distribution of protein and lipid molecules within the bilayer membrane.

Quantitative characterization of the lateral distribution of membrane proteins within the lipid bilayer

The dependence of the lateral distribution of membrane proteins on the size, protein/lipoid molar ratio, and the magnitude of the interaction potentials has been investigated by computer modeling protein-lipid distributions with Monte Carlo calculations. These results have allowed us to develop a quantitative characterization of the distribution of membrane proteins and to correlate these distributions with experimental observables. The topological arrangement of protein domains, protein plus annular lipid domains, and free lipid domains is described in terms of radial distribution, pair connectedness, and cluster distribution functions. The radial distribution functions are used to measure the distribution of intermolecular distances between protein molecules, whereas the pair connectedness functions are used to estimate the physical extension of compositional domains. It is shown that, at characteristic protein/lipid molar ratios, previously isolated domains become connected, forming domain networks that extend over the entire membrane surface. These changes in the lateral connectivity of compositional domains are paralleled by changes in the calculated lateral diffusion coefficients and might have important implications for the regulation of diffusion controlled processes within the membrane.

Flow partitioning in symmetric cascades of branches

We have found markedly nonuniform partitioning of flow in idealized models of physiological cascades of branches. Liquids having viscosities of 0.8-7.0 cP were used to investigate this effect systematically in a regime characterizing a limited range of pulmonary flows, comprising inlet flow rates of 500-3,000 ml/min and branch diameters of 1.0 cm ID. Factors that affect the nonuniformity of inspiratory flow include inlet velocity profile and flow rate, cascade aspect (L/D) ratio, exit pressure distribution, and, to a lesser extent, kinematic viscosity (mu/rho). More qualitative observations using sinusoidally oscillating airflow revealed inspiratory and expiratory flow patterns to be quite dissimilar, emphasizing the inadequacy of a resistance model of flow partitioning based on Kirchhoff's law. These results might suggest, in part, why regional ventilation in man is flow or frequency dependent and how bronchial smooth muscle could fine tune regional ventilation.

Monte Carlo studies of the lateral organization of molecules in two-component lipid bilayers

The lateral organization of two-component phosphatidylcholine bilayers has been investigated using Monte Carlo calculations based upon non-ideality parameters deduced from the phase diagrams of these mixtures. The results are used to develop a quantitative description of the distribution and spatial localization of compositional regions along the bilayer plane in both the gel and liquid crystalline phases. In particular, a detailed analysis of the physical extension (lateral connectivity) and compactness of the compositional clusters is made. It is concluded that the chemical composition of the membrane, the physical state of the bilayer and the interaction energies between molecules greatly influence the lateral connectivity and compactness of compositional regions and that these parameters might play an important role in the formation of diffusional pathways along the membrane plane.

Compositional domain structure in phosphatidylcholine--cholesterol and sphingomyelin--cholesterol bilayers

the lateral distribution of cholesterol in phospholipid bilayers has been investigated through a method of Monte Carlo calculations, using interaction energies deduced from calorimetric results for cholesterol-phospholipid mixtures. Analysis of computer-generated bilayer configurations allows calculation of the spatial localization and relative abundance of distinct regions of varying cholesterol content along the plane of the bilayer. An interfacial phospholipid region between cholesterol-bound and cholesterol-free domains is found to extend one lipid beyond the cholesterol-bound domain for mixtures of cholesterol with palmitoyl sphingomyelin, lignoceroyl sphingomyelin, and dipalmitoyl phosphatidylcholine. The results indicate that the degree of nonideality in the mixing of cholesterol is dependent on fatty acid chain length and that cholesterol mixes more ideally in sphingomyelins than in phosphatidylcholines of equal chain length. It is found that at approximately 20 mol % cholesterol the cholesterol-rich areas suddenly become connected, forming a network that extends over the entire bilayer. This change in the lateral connectivity of the cholesterol-rich domains occurs over a narrow concentration interval and is presumably responsible for the abrupt change in the lateral diffusion coefficient observed at this concentration.

Estimation of the lateral distribution of molecules in two-component lipid bilayers

A new formalism to investigate the lateral distribution of molecules in lipid bilayers has been developed, and the results have been applied to the case of phosphatidylcholine mixtures. It is demonstrated that the experimental phase diagrams for these mixtures can provide the necessary information to generate computer-simulated bilayers with the desired molecular interactions and lattice constraints. Analysis of these computer-generated bilayers allows calculation of the number of contacts between like and unlike molecules, the average size and number of compositional clusters, and the pair correlation functions. The results of this analysis provide a full quantitative description of the molecular organization of phosphatidylcholine within the plane of the bilayer.