The measurement of kappach factors for application with the IPEMB very low energy dosimetry protocol

In 1996. the IPEMB issued a new code of practice detailing the procedures by which the output of therapeutic kilovoltage x-ray devices are to be determined. For x-ray beam qualities in the range 0.035-1.0 mm Al half-value thickness (HVL), the equation for converting the instrument reading into absorbed dose to water contained a factor named kch. This was included to account for the change in response of the parallel plate chamber from its calibration conditions free in air to those in the user's measurement phantom. As no data were available with which to quantify this factor at very low energies, the code advised that the user take a value of unity until sufficient data became available upon which to base an addendum. In this work, kch values have been determined for four chambers: two PTW 23344 large volume soft x-ray chambers, one PTW 23342 small volume soft x-ray chamber and a Markus electron chamber. Variations in the value of kch were investigated for changes in FSD, applicator size and beam quality. The water equivalence of the Mix-D phantom used for these measurements was also verified. A comparison of the results for the two PTW 23344 chambers showed no significant differences for any experimental situation, indicating that kch is a factor of chamber design rather than variations in construction. No variation in kch was identified with changes in FSD. A small dependence on applicator size was identified for larger applicators, and this was found to be dependent upon chamber design. The measured values of kch were found to increase with energy and again differences were seen between chamber designs. Overall, the values of kch recorded during these measurements ranged from 1.01 to 1.08. These results highlight a significant underestimation of doses calculated using the very low energy code of practice. This supports the need for further work to confirm these results. and the production of an addendum to the code in its present form.

Lenercept (p55 tumor necrosis factor receptor fusion protein) in severe sepsis and early septic shock: a randomized, double-blind, placebo-controlled, multicenter phase III trial with 1,342 patients

OBJECTIVE

Phase III study to confirm a trend observed in a previous phase II study showing that a single dose of lenercept, human recombinant p55 tumor necrosis factor receptor-immunoglobulin G1 (TNFR55-IgG1) fusion protein, decreased mortality in patients with severe sepsis or early septic shock.

DESIGN

Multicenter, double-blind, phase III, placebo-controlled, randomized study.

SETTING

A total of 108 community and university-affiliated hospitals in the United States (60), Canada (6) and Europe (42).

PATIENTS

A total of 1,342 patients were recruited who fulfilled the entry criteria within the 12-hr period preceding the study drug administration.

INTERVENTION

After randomization, an intravenous dose of 0.125 mg/kg lenercept or placebo was given. The patient was monitored for up to 28 days, during which standard diagnostic, supportive, and therapeutic care was provided.

MEASUREMENTS AND MAIN RESULTS

The primary outcome measure was 28-day all-cause mortality. Baseline characteristics were as follows: a total of 1,342 patients were randomized; 662 received lenercept and 680 received placebo. The mean age was 60.5 yrs (range, 17-96 yrs); 39% were female; 65% had medical admissions, 8% had scheduled surgical admissions, and 27% had unscheduled surgical admissions; 73% had severe sepsis without shock, and 27% had severe sepsis with early septic shock. Lenercept and placebo groups were similar at baseline with respect to demographic characteristics, simplified acute physiology score II-predicted mortality, profiles of clinical site of infection and microbiological documentation, number of dysfunctioning organs, and interleukin-6 (IL-6) plasma concentration. Lenercept pharmacokinetics were similar in severe sepsis and early septic shock patients. Tumor necrosis factor was bound in a stable manner to lenercept as reflected by the accumulation of total serum tumor necrosis factor alpha concentrations. There were 369 deaths, 177 on lenercept (27% mortality) and 192 on placebo (28% mortality). A one-sided Cochran-Armitage test, stratified by geographic region and baseline, predicted 28-day all-cause mortality (simplified acute physiology score II), gave a p value of .141 (one-sided). Lenercept treatment had no effect on incidence or resolution of organ dysfunctions. There was no evidence that lenercept was detrimental in the overall population.

CONCLUSION

Lenercept had no significant effect on mortality in the study population.

Recruitment of research participants from U.S. jury pools

Psychological research is often criticized for routine use of a narrow and unrepresentative study population-college students. This study investigated the feasibility of recruiting research participants from U.S. jury pools, which by law must include a representative cross-section of the public. A questionnaire was mailed to the jury administrators in the 217 U.S. state court jurisdictions with populations of 250,000 or more. Court officials representing 79 jurisdictions in 30 states and the District of Columbia returned surveys (36% response rate). In addition, respondents who indicated in the mail survey that their court had previously allowed outside investigators to recruit jurors also completed a follow-up telephone interview. While the majority of jurisdictions (61%) opposed participation of jurors in research, 31 jurisdic tions (39%) did not object to this practice. Only 8 of the nonopposed jurisdictions had been asked to host research, and 7 had agreed to do so. The jurisdictions that opened their jury pools to researchers employed a number of strategies to circumvent potential problems and generally reported that hosting research was a positive experience. Jury pools represent a viable and relatively untapped source of research participants. Many courts are open to the possibility of hosting research but have never been asked to do so. Both researchers and court officials should be reassured by the positive experiences of courts that have hosted research.

Identification of genes induced by inflammatory cytokines in airway epithelium

Epithelial cells lining the airways are thought to play a prominent role in respiratory diseases. We utilized cDNA representational difference analysis to identify the genes in which expression is induced by the proinflammatory cytokines tumor necrosis factor-alpha and interleukin-1beta in primary human bronchial epithelial cells and hence are relevant to airway inflammation. Hybridization of the subtraction product to arrayed cDNAs indicated that known tumor necrosis factor-alpha- and interleukin-1beta-inducible genes such as B94, Zfp36, and regulated on activation normal T cell expressed and secreted were represented, confirming the success of the subtraction experiment. A 1,152-clone library potentially representing genes with higher transcript levels in cytokine-treated human bronchial epithelial cells was generated and sequenced. Sequence similarity searches indicated that these clones represented 57 genes of known function, 1 gene of unknown function, 6 expressed sequence tags, and 2 novel sequences. The expression of 19 of these clones was studied by a combination of Northern blotting and RT-PCR analyses and confirmation of differential expression for 10 known genes, 2 expressed sequence tags, and a novel sequence not represented in any of the public databases was obtained. Thus cDNA representational difference analysis was utilized to isolate known and novel differentially expressed genes, which putatively play a role in airway inflammation.

Comparison of two methods for serotyping Campylobacter spp

Two serotyping schemes (Penner and Laboratory of Enteric Pathogens [LEP]) based on soluble heat-stable antigens were used to analyze 3,788 Campylobacter sp. isolates. A significant percentage (36.6%) was untypeable using LEP serotyping; greater cross-reaction was also observed. The relative discrimination capabilities of the techniques were similar. Penner serotyping fulfils more of the requisite criteria for typing methods.

Preliminary characterisation of digestive proteases of the green mirid, Creontiades dilutus (Hemiptera: Miridae)

Protease activities in the secreted saliva, salivary glands and midgut of the green mirid, Creontiades dilutus, were investigated. The saliva and salivary glands had more protease activity than the midgut, but no differences in protease activity levels were detected between male and female mirids, adult mirids and third instar nymphs, or between fed and starved mirids. In the salivary glands, chymotrypsin-like serine proteases predominated, as characterised by inhibitor specificity, basic pH optima, and hydrolysis of N-benzoyl-L-tyrosine p-nitroanilide and N-succinyl-ala-ala-pro-leu p-nitroanilide. The pH optimum of midgut extracts was acidic (pH 4), implying that acidic proteases predominate. However, protease activity was inhibited substantially by both aprotinin and E-64, suggesting the presence of both serine and cysteine proteases in the midgut of the green mirid.

A core middleware service in H.I.S.: the experience of IC_PIDRM

The exploding usage of telematics and internet techniques also in the Health Care environment imposes a re-thinking of the basic services that an Information System should provide. The standard CEN TC251 HISA ENV 12967, "Health Information System Architecture" while addressing specifications for patient coherent identification between departmental and global hospital information systems, leaves a cloud of uncertainty about inter hospital information system collaboration, delegating a pure technological layer (the so called "bitway" layer) to solve communication and interactions. The faced reality of heterogeneous systems in a regional healthcare environment drives the design of an architecture that includes functional middleware services implemented to create co-operation among several local identification systems and laying on a technical platform able to deal with distribution. This article explains how the InterCare HC4011 project designed and tested such services, and the conclusions reached.

Nutrition and wound healing: what is the link?

Given the important role played by nutrients in wound healing, all patients with wounds should receive a nutritional assessment. Action must then be taken to address any deficiency.

Comparison of two skin care regimes for incontinence

It is estimated that 30% of nursing home residents may be faecally incontinent, with those figures rising to 60% for patients in long-stay hospitals (Royal College of Physicians, 1995). Maintaining skin integrity for these patients can be complex. With little clinical information to support carers, choosing a skin care regime that maintains skin integrity for this high-risk group can be difficult. This study aims to compare two recognized skin care regimes, used in the cleansing of patients' skin following an episode of incontinence, and their impact on patients' skin integrity. A total of 93 patients were recruited to the trial from five care of the elderly or dependent service providers. The subjects were randomly allocated to either group A (soap and water; n = 49), or group B (Clinisan (Vernacare); n = 44). Initially, 33 patients in both groups started with healthy skin. However, the results of the final assessment identified only 17 subjects in group A remaining healthy, compared with 27 in group B.

Soft tissue reconstruction for calcaneal fractures or osteomyelitis

A systematic approach of the surgical management of a calcaneal fracture can minimize the potential of soft tissue complications. When reducing a closed calcaneal fracture, the incision used affects the postoperative complications. The L-shaped incision with the horizontal limb lying on the lateral glabrous junction ensures maximum blood flow to either side of the incision. Whether or not the wound can be closed primarily depends on the preexisting edema, the lost calcaneal height, and the delay between the fracture and reduction (Fig. 20). The wrinkle test is a good indicator that the incision can be closed primarily if the amount of height restored is minimal. If the edema is too great, steps should be taken to reduce it sufficiently to allow successful wound closure. If the wound, after reduction, is too wide to allow primary closure, an ADM flap laterally or an AHM flap medially should be used. For larger defects, a free flap should be considered. The three important steps to reconstruction of soft tissue defects around the calcaneus include good blood supply, a infection-free wound, and the simplest soft tissue reconstructive option that covers the wound successfully. Adequate blood supply can be determined by the use of Doppler. If the supply is inadequate, revascularization is necessary before proceeding. Achieving a clean wound requires aggressive debridement, intravenous antibiotics, and good wound care. Adjuncts that can help in achieving a clean wound include topical antibiotics (silver sulfadiazine), the VAC, and hyperbaric oxygen. Osteomyelitis has to be treated aggressively. Any suspicious bone has to be removed. Only clean, healthy, bleeding bone is left behind. Antibiotic beads can be useful when there is doubt as to whether the cancellous bone is infection-free. The beads are not a substitute for good debridement, however. Soft tissue reconstruction ranges from delayed primary closure to the use of microsurgical free flaps (Fig. 21). When bone or hardware is exposed, a muscle flap should cover the wound because of the extra blood supply it carries with it. The soft tissue option depends on the width of the wound. For wounds 1 cm wide or less, the options include allowing the wound to close by secondary intention (VAC), delayed primary closure, or a local muscle flap. For wounds 2 cm wide or less, allowing the wound to close by secondary intention (VAC) and a local muscle flap are the best options. For wider wounds, one has to assess whether the local muscle flap has sufficient bulk to close the defect. If it does, it is the simplest solution. If the local muscle is inadequate, a microsurgical free flap has to be used. The VAC sometimes can convert a large wound to a smaller wound so that a local muscle flap can be used. This procedure takes time, however, and adds to the cost of the repair.

The reliability and validity of self-reported reproductive history and obstetric morbidity amongst Birth to Ten mothers in Soweto

OBJECTIVE

To assess whether self-reports of reproductive history and obstetric morbidity provide an accurate basis for clinical decision-making. SETTING, PARTICIPANTS AND METHODS: Self-reports of maternal age and reproductive history, together with clinical measurements of five medical disorders, were abstracted from the obstetric notes of 517 mothers whose children were enrolled in the Birth to Ten study. These data were compared to self-reported information collected by interview during the Birth to Ten study.

FINDINGS

The reliability of self-reported age and gravidity was high (R = 0.810-0.993), yet self-reports of previous miscarriages, terminations, premature- and stillbirths were only fairly reliable (Kappa = 0.48-0.50). Self-reported diabetes and high blood pressure had specificities of more than 95% for glycosuria, hypertension and pre-eclampsia. However, the specificity of self-reported oedema for hypertensive disorders and the specificity of self-reported urinary tract infection for STD seropositivity were only around 65%.

CONCLUSIONS

The modest reliability and limited validity of self-reported obstetric morbidity undermines the clinical utility of this information.

RECOMMENDATIONS

These results strengthen the case for providing mothers with "Home-based Maternal Records" to facilitate access to accurate obstetric information during subsequent clinical consultations.

Genome scan identifies a locus affecting gamma-globin level in human beta-cluster YAC transgenic mice

Genetic factors affecting postnatal gamma-globin expression--a major modifier of the severity of both beta-thalassemia and sickle cell anemia--have been difficult to study. This is especially so in mice, an organism lacking a globin gene with an expression pattern equivalent to that of human gamma-globin. To model the human beta-cluster in mice, with the goal of screening for loci affecting human gamma-globin expression in vivo, we introduced a human beta-globin cluster YAC transgene into the genome of FVB/N mice. The beta-cluster contained a Greek hereditary persistence of fetal hemoglobin (HPFH) gamma allele, resulting in postnatal expression of human gamma-globin in transgenic mice. The level of human gamma-globin for various F1 hybrids derived from crosses between the FVB/N transgenics and other inbred mouse strains was assessed. The gamma-globin level of the (C3HeB/FeJ x FVB/N)F1 transgenic mice was noted to be significantly elevated. To map genes affecting postnatal y-globin expression, we performed a 20-centiMorgan (cM) genome scan of a (C3HeB/FeJ x FVB/N)F1 transgenics x FVB/N backcross, followed by high-resolution marker analysis of promising loci. From this analysis we mapped a locus within an 18-cM interval of mouse Chromosome (Chr) 1 (LOD = 4.3) that contributes 10.9% of variation in gamma-globin level. Combining transgenic modeling of the human beta-globin gene cluster with quantitative trait analysis, we have identified and mapped a murine locus that impacts on human gamma-globin level in vivo.

A multicenter, randomized clinical study to evaluate the effect on cognitive function of topiramate compared with valproate as add-on therapy to carbamazepine in patients with partial-onset seizures

PURPOSE

This study compares the cognitive effects of topiramate (TPM) with those of valproate (VPA) using efficacious doses of each drug when used as adjunctive therapy to carbamazepine (CBZ). A key question of the study is to what extent a more gradual introduction of TPM improves tolerability and prevents cognitive impairment.

METHODS

The study is a multicenter, randomized, observer-blinded, parallel-group clinical trial with VPA or TPM given as first-line add-on therapy to steady-state treatment with CBZ. TPM is introduced at 25 mg and increased with weekly 25mg/d increments to a minimum dosage of 200 mg/d. The target dosage ranges from 200 to 400 mg/d for TPM and is 1800 mg/d for VPA. The study evaluates cognitive function changes from baseline to end point (after 20 weeks of treatment) and during titration (after 8 weeks of treatment). The primary outcome measure is the difference between the treatments (TPM versus VPA) in change from baseline to end point and change from baseline to titration, using a 95% confidence interval approach.

RESULTS

For the 10 baseline-to-end point comparisons, one test measuring short-term verbal memory (Rey Auditory Verbal Learning Test) yields a statistically significant difference between the treatments (p = 0.02), showing worsening for TPM and improvement of scores for VPA. The 10 baseline-to-titration comparisons also show one statistically significant difference, again for a test measuring short-term memory (Recognition of Words; p = 0.04), showing a larger change in the negative direction for TPM. None of the mood tests or the test for subjective complaints shows statistically significant differences between the treatments, although more scores are in the negative direction for TPM during titration.

CONCLUSION

Although the pattern of changes in the negative direction seems consistent with clinical information, the differences found between the treatments are small. An important finding of our study is that, when the results are compared with those of other studies, it is clear that gradual introduction of TPM can reduce the extent of cognitive impairment (with a maximum of about 0.6 SD).

High-resolution field shaping utilizing a masked multileaf collimator

Multileaf collimators (MLCs) have become an important tool in the modern radiotherapy department. However, the current limit of resolution (1 cm at isocentre) can be too coarse for acceptable shielding of all fields. A number of mini- and micro-MLCs have been developed, with thinner leaves to achieve approved resolution. Currently however, such devices are limited to modest field sizes and stereotactic applications. This paper proposes a new method of high-resolution beam collimation by use of a tertiary grid collimator situated below the conventional MLC. The width of each slit in the grid is a submultiple of the MLC width. A composite shaped field is thus built up from a series of subfields, with the main MLC defining the length of each strip within each subfield. Presented here are initial findings using a prototype device. The beam uniformity achievable with such a device was examined by measuring transmission profiles through the grid using a diode. Profiles thus measured were then copied and superposed to generate composite beams, from which the uniformity achievable could be assessed. With the average dose across the profile normalized to 100%, hot spots up to 5.0% and troughs of 3% were identified for a composite beam of 2 x 5.0 mm grids, as measured at Dmax for a 6 MV beam. For a beam composed from 4 x 2.5 mm grids, the maximum across the profile was 3.0% above the average, and the minimum 2.5% below. Actual composite profiles were also formed using the integrating properties of film, with the subfield indexing performed using an engineering positioning stage. The beam uniformity for these fields compared well with that achieved in theory using the diode measurements. Finally sine wave patterns were generated to demonstrate the potential improvements in field shaping and conformity using this device as opposed to the conventional MLC alone. The scalloping effect on the field edge commonly seen on MLC fields was appreciably reduced by use of 2 x 5.0 mm grids, and still further by the use of 4 x 2.5 mm grids, as would be expected. This was also achieved with a small or negligible broadening of the beam penumbra as measured at Dmax.

Evaluation of photo radar program in British Columbia

This article presents the results of an evaluation of the speed and traffic safety effects of the photo radar program in British Columbia (BC) after 1 year of full operation. Traffic speed data were collected from the photo radar units and from induction loops installed across the province. Traffic collision and injury data were obtained from police investigation reports and from BC ambulance services records. The study employed a number of analytical frameworks, including simple before and after comparison, time-series cross-sectional analysis, and interrupted time series analysis. The study revealed a dramatic reduction of speed at photo radar deployment sites. A reduction of 2.4 km/h in mean speed was also observed at selected monitoring sites where enforcement was not likely to be present. The reduction of speed was accompanied by a decrease in collisions, injuries and fatalities. The analysis found a 25% reduction in daytime unsafe speed related collisions, an 11% reduction in daytime traffic collision victims carried by ambulances and a 17%, reduction in daytime traffic collision fatalities.

Misdiagnosis of epilepsy: many seizure-like attacks have a cardiovascular cause

OBJECTIVES

We sought to investigate the value of cardiovascular tests to diagnose convulsive syncope in patients with apparent treatment-resistant epilepsy.

BACKGROUND

As many as 20% to 30% of epileptics may have been misdiagnosed. Many of these patients may have cardiovascular syncope, with abnormal movements due to cerebral hypoxia, which may be difficult to differentiate from epilepsy on clinical grounds.

METHODS

Seventy-four patients (33 men, mean age 38.9 +/- 18 years [range 16 to 77]) who were previously diagnosed with epilepsy were studied. Inclusion criteria included continued attacks despite adequate anticonvulsant drug treatment (n = 36) or uncertainty about the diagnosis of epilepsy, on the basis of the clinical description of the seizures (n = 38). Each patient underwent a head-up tilt test and carotid sinus massage during continuous electrocardiography, electroencephalography and blood pressure monitoring. Ten patients subsequently underwent long-term electrocardiographic (ECG) monitoring with an implantable loop recorder.

RESULTS

In total, an alternative diagnosis was found in 31 patients (41.9%), including 13 (36.1%) of 36 patients taking an anticonvulsant medication. Nineteen patients (25.7%) developed profound hypotension or bradycardia during the head-up tilt test, confirming the diagnosis of vasovagal syncope. One other patient had a typical vasovagal reaction during intravenous cannulation. Two patients developed psychogenic symptoms during the head-up tilt test. Seven patients (9.5%) had significant ECG pauses during carotid sinus massage. In two patients, episodes of prolonged bradycardia correlated precisely with seizures according to the insertable ECG recorder.

CONCLUSIONS

A simple, noninvasive cardiovascular evaluation may identify an alternative diagnosis in many patients with apparent epilepsy and should be considered early in the management of patients with convulsive blackouts.

The use of Clinisan in the skin care of the incontinent patient

The use of skin care regimes for the cleansing of skin when a patient has been incontinent is becoming accepted practice in maintaining healthy skin. Clinisan, produced by Venture Healthcare, is a soap-free, pH balanced foam which has been specifically formulated to cleanse the skin of incontinent patients who are vulnerable to skin breakdown.

cDNA-RDA of genes expressed in fetal and adult lungs identifies factors important in development and function

The identification of genetic factors important in lung development and function will help in understanding the underlying molecular mechanisms of respiratory disease. Representational difference analysis of cDNA (cDNA-RDA) is a PCR-based subtractive enrichment procedure for the isolation of differentially expressed genes. We performed cDNA-RDA and isolated genes expressed more abundantly in fetal and adult lungs. Fifty-four clones potentially representing genes with higher transcript levels in the fetal lung were sequenced. Sequence similarity searches indicated that these clones included 12 known genes, a discoidin-like domain-containing gene, six expressed sequence tags (ESTs), and one novel sequence. Fifty-six clones potentially representing genes expressed more abundantly in the adult lung were also cloned and sequenced. Of these, 16 known human genes were represented along with two sequences significantly similar to known mouse genes and two novel sequences. Several of these known genes are implicated in stress response and lung protection. Thus cDNA-RDA was successfully used to isolate known and novel differentially expressed genes, which putatively play an important role in human lung development.

Application of directly coupled HPLC-NMR-MS/MS to the identification of metabolites of 5-trifluoromethylpyridone (2-hydroxy-5-trifluoromethylpyridine) in hydroponically grown plants

Directly coupled HPLC-NMR-MS was used to characterize two major metabolites of 5-trifluoromethylpyridone (2-hydroxy-5-trifluoromethylpyridine), a model compound for herbicides, after it had been dosed into hydroponically grown maize plants. The combination of NMR and MS data allowed the identification of both of these metabolites, namely, the N-glucoside and O-malonylglucoside conjugates of the parent pyridone. This work demonstrates the efficiency and the potential application of HPLC-NMR-MS to the investigation of the metabolism of agrochemicals. The work also indicates that combination of the use of hydroponically grown plants and directly coupled HPLC-NMR-MS allows rapid identification of metabolites with little sample preparation.

Klebsiella pneumoniae with extended spectrum beta-lactamase activity associated with a necrotizing enterocolitis outbreak

BACKGROUND

Necrotizing enterocolitis (NEC) is the most common gastrointestinal emergency in newborn infants, affecting primarily premature neonates. Clustering of cases in epidemics is well-described; many are associated with an identifiable pathogen.

PATIENTS AND METHODS

Case reports are presented of six neonates seen with NEC during a 2-month period in 1998. All bacterial isolates were subjected to antibiotic testing, determination of MIC and molecular fingerprinting.

RESULTS

Klebsiella pneumoniae with extended spectrum beta-lactamase production was isolated from blood cultures of all six patients. In five patients the isolate appeared to be a single clone. The onset of NEC in the patients was earlier, more rapid and more severe than usual. Four of the six required surgery and five required mechanical ventilation. Two of the six patients died, but only one was directly related to a complication of NEC. All of the patients developed severe thrombocytopenia (platelet count <20 x 10(9)/l), and three developed hepatitis. The K. pneumoniae proved difficult to eradicate. Extended courses of multiple antibiotics were administered and measures were introduced to reduce overcrowding and improve infection control.

CONCLUSION

The isolation of a single clone of K. pneumoniae with extended spectrum of beta-lactamase activity during an NEC outbreak highlights the need for strict infection control. This organism caused significant morbidity and was difficult to treat.

Usefulness of ibutilide in facilitating successful external cardioversion of refractory atrial fibrillation

We repeated direct-current cardioversion of atrial fibrillation after ibutilide injection in patients who failed conventional cardioversion. Eleven of 12 patients (92%) had successful cardioversion and avoided the need for internal cardioversion.