Validation of endoscopic ultrasound measured flow rate in the azygos vein using a flow phantom

Increase in flow rate within the azygos vein may be used as an indicator of the degree of liver cirrhosis. The aim of this study was to evaluate the error in measurement of flow rate using a commercial endoscopic ultrasound system, using a flow phantom that mimicked azygos vein depth, diameter and flow rate. Diameter was underestimated in all cases, with an average underestimation of 0.09 cm. Maximum velocity was overestimated, by 4 ± 4% at 50°, 11 ± 3% at 60° and 23 ± 7% at 70°. The increase in error with beam-vessel angle is consistent with the error as arising from geometric spectral broadening. Flow was underestimated by amounts up to 33%, and it is noted that the overestimation caused by geometric spectral broadening is in part compensated by underestimation of diameter. It was concluded that measurement of flow rate using a commercially available endoscopic ultrasound system is dependent on the beam-vessel angle, with errors up to 33% for typical vessel depths, diameter and beam-vessel angle.

The acoustic scatter from single biSphere microbubbles

Single microbubble acoustic acquisitions provide information on the behaviour of microbubble populations by enabling the generation of large amounts of data. Acoustic signals from single polylactide-shelled and albumin coated biSphere™ microbubbles have been acquired. The responses observed from a range of incident frequencies and acoustic pressures varied in duration. Partial echoes shorter than the incident pulse duration have been observed for low frequency pulses of sufficient amplitude, suggesting release of gas from bubbles. The results presented suggest that the mechanism of scatter from hard shelled agents may be shell disruption and gas release, or partly from gas leaking from defected shell sites, which has previously not been observed optically. These results can provide the basis for improved imaging through optimization of incident pulse parameters, with potential benefits to both diagnostic and therapeutic techniques.

Thrombocytosis in neonates and young infants: a report of 25 patients with platelet counts of > or = 1000000 microl(-1)

OBJECTIVE

Thrombocytosis has been reported in neonates and young infants, but little is known of its prevalence, timing of onset, associated conditions, sequelae and outcomes. To better understand this condition, we used the data repositories of a multi-hospital health-care system to identify all individuals <or=140 days old (20 weeks) who, during the past 6 years, had a platelet count of >or=1000000 microl(-1).

STUDY DESIGN

We identified all infants with extreme thrombocytosis (using the Sutor definition of a platelet count of >or=1000000 microl(-1)) during the period of January 2003 through December 2008 in any Intermountain Healthcare facility. We obtained the information provided in this report from electronic and paper records.

RESULT

Among 40 471 infants who had one or more platelet counts performed in this period, 25 had extreme thrombocytosis. No cases were identified in the first week after birth, 40% were recognized between the second and fourth weeks and 40% between the fifth and eighth week. The prevalence of thrombocytosis had no relationship with birth weight or gestational age but a slight predominance of female patients (15/25) was noted. In all, 26 episodes were found among the 25 infants: 12 episodes involved an antecedent infectious disease, 8 had an antecedent surgical procedure, 4 had the anemia of prematurity and 1 each had congenital adrenal hyperplasia and opiate withdrawal syndrome. No pathological thromboses or hemorrhages or other sequelae were detected and all episodes resolved with no deaths.

CONCLUSION

The thrombocytosis cases that we report were all consistent with reactive thrombocytosis (also known as secondary thrombocytosis); none seemed to be essential (primary) thrombocytosis. We speculate that the pathogenesis involves increased platelet production due to megakaryopoietic stimulators induced by an infectious or inflammatory condition. From this series and previous reports, young infants with platelet counts up to 1300000 microl(-1) do not seem to have a significant risk of thrombotic or hemorrhagic problems, and do not generally require anti-platelet or cytoreductive treatment.

Temporal compounding of cardiac ultrasound data: Improving image quality and clinical measurement repeatability

Echocardiography provides a powerful and versatile tool for assessing cardiac morphology and function. However, cardiac ultrasound suffers from speckle as well as static and dynamic noise. Over the last three decades, a number of studies have attempted to address the challenging problem of speckle/noise suppression in cardiac ultrasound data. No single method has managed to provide a widely accepted solution. Temporal Compounding is a noise suppression method that utilises spatial averaging of temporally aligned cardiac B-Mode data. Reliable temporal alignment is vital for effective Temporal Compounding. In this study we introduce a novel, accurate and robust technique for the temporal alignment of cardiac cycles with variable temporal characteristics and examine the effect of Temporal Compounding in four clinical measurements performed on routine echocardiographic examinations. Results from 32 patients demonstrate speckle/noise suppression, shadowing reduction, anatomical structure enhancement and improvement in measurement repeatability with no significant or systematic bias introduced. Temporally compound data may be able to provide a good alternative to B-Mode data in clinical measurements as well as a first step to further post-processing of cardiac ultrasound data.

Target-specific, histology-independent, randomized discontinuation study of lapatinib in patients with HER2-amplified solid tumors

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Background: The current paradigm of histology-specific drug development may not be optimal in the era of targeted therapeutics. We sought to explore the activity of lapatinib, an oral tyrosine kinase inhibitor of HER2, with a trial design focused on the target rather than on tumor-type. Methods: Patients (pts) with HER2-amplified treatment-refractory metastatic gastro- esophageal (G/E), bladder (B), ovarian (O), or uterine (U) tumors were enrolled into a double-blinded randomized discontinuation study of lapatinib 1500 mg PO daily (malignancies selected based on reported frequencies of HER2 amplification). The planned sample size was 250 HER2+ pts, with the goal of then randomizing 100 pts with SD at week (wk) 12 to either lapatinib or placebo until progressive disease (PD). Pts who responded at wk 12 (CR or PR) continued on lapatinib; those who progressed were discontinued from study. Primary objectives were response rate at 12 wks and percentage of pts who remain progression free at 24 wks. Secondary objectives were duration of response, progression free survival (PFS) after randomization, and determination of the incidence of HER2 amplification in multiple tumor types. Futility analyses were preplanned to ensure feasibility of screening and of randomization (i.e. a sufficient rate of non- progression at 12 wks). Results: A total of 145 pts were screened (G/E=47, B=35, O=58, U=5); 42 were HER2-amplified (G/E=16, B=13, O=13, U=0) and 32 (G/E=13, B=9, O=10) were enrolled. At wk 12, 1 (3%) patient had a CR, 10 (31%) had SD, 19 (59%) had PD, and 2 (6%) were unknown. Median time to progression during open-label lapatinib was 78 days, 95% CI (42, 92). Only 7 pts with SD underwent randomization. Two pts with esophageal cancer remain on study; one (CR at wk 12) remains a CR at wk 60 and the other (SD at wk 12) remains with SD at wk 36. Low response rate coupled with slow screening and enrollment led to early study closure. Conclusions: Basing trial eligibility on a target, versus histologic classification, is challenging. While HER2 amplifications appear to be prevalent in select non-breast tumors, lapatinib monotherapy in refractory disease is associated with a low level of objective responses.

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Drugs in the aetiology of agranulocytosis and aplastic anaemia

Agranulocytosis and aplastic anaemia are rare but serious conditions known to be caused by numerous drugs. Most of what is known or suspected about the aetiology is based on case reports, with only a few formal epidemiological studies that provide quantitative estimates of risk. Updated results have been obtained from a combined analysis of data from 3 case-control studies that used similar methods: the International Agranulocytosis and Aplastic Anemia Study (IAAAS), conducted in Israel and Europe; a study conducted in the northeast US; and a study conducted in Thailand. Totals of 362 cases of agranulocytosis, 454 cases of aplastic anaemia and 6458 controls were included in the analyses. The IAAAS and Thai study were population-based, providing estimates of the incidence of the 2 dyscrasias. The overall annual incidence of agranulocytosis in the ambulatory population was 3.4/10(6) in the IAAAS and 0.8/10(6) in Thailand; by contrast the incidence of aplastic anaemia was 2.0/10(6) in the IAAAS and 4.1/10(6) in Thailand. A total of 21 compounds were significantly associated with an increased risk of agranulocytosis in the IAAAS and US studies. Excess risks ranged from 0.06 to 13 cases/10(6) users/wk; the most strongly associated drugs were procainamide, anti-thyroid drugs and sulphasalazine. An association with drugs that had previously been suspected was also seen in Thailand. The overall aetiologic fractions of agranulocytosis due to drug use were 62% in the IAAAS, 72% in the US and 70% in Thailand. Eleven drugs were significantly associated with an increased risk of aplastic anaemia, with excess risks ranging from 1.4 to 60 cases/10(6) users in a 5-month period. The most strongly associated drugs were penicillamine, gold and carbamazepine. Aetiologic fractions were 27% in the IAAAS, 17% in the US and 2% in Thailand, which paralleled the prevalence of use of associated drugs in the 3 populations. The present results confirm that agranulocytosis is largely a drug-induced disease, with similar proportions accounted for in 3 disparate geographic regions. By contrast, although many of the expected associations were observed for aplastic anaemia, most of the aetiology is not explained by drugs. For all associated drugs, the excess risks are sufficiently low that blood dyscrasias should not figure prominently in the balancing of risks and benefits.

Incidence and non-drug aetiologies of aplastic anaemia in Thailand. The Thai Aplastic Anaemia Study Group

A population-based, case-control study of aplastic anaemia has been conducted in Thailand since 1989. Up to December 1994, the overall annual incidence was 3.9/10(6) in Bangkok, 5.0/10(6) in Khonkaen and 3.0/10(6) in Songkla. In Bangkok, the incidence peaked in 2 age groups (at 15-24 yr and > or = 60 yr), whereas in Khonkaen and Songkla there was a consistent increase in incidence with increasing age. The results of case-control analyses for non-drug risk factors indicate a strong inverse association with socio-economic status present in all 3 areas; a strong association with grain farming in the 2 rural areas that does not appear to be explained by pesticides; an association with occupational exposure to solvents in Bangkok; and a positive association with hepatitis A seropositivity.

Basic considerations in the use of coded excitation for color flow imaging applications

Coded excitation is now a well-established technique in medical ultrasound for B-mode imaging applications. It enables a gain in depth of penetration, without sacrificing the spatial resolution and maintaining an acceptable peak intensity for patient safety. The rationale of this technique for velocity estimation applications still has to be formulated in more precise terms. In particular, differences in the situation that arise in color flow imaging (CFI) applications from typical B-mode imaging conditions, such as signal-to-noise ratio conditions, pulsing strategy, and safety requirements, need to be specifically addressed to assess more quantitatively the potential of this technique. This paper discusses the potential improvement in sensitivity, resolution, and statistical performance provided by coded excitation for CFI applications from theoretical considerations and simulations.

Single microbubble response using pulse sequences: initial results

The study of acoustic scattering by single microbubbles has the potential to offer improved signal processing techniques. A microacoustic system that employs a hydrodynamically-focused flow was used to detect radiofrequency (RF) backscatter from single microbubbles. RF data were collected using a commercial scanner. Results are presented for two agents, namely Definity (Lantheus Medical Imaging, N. Billerica, MA, USA) and biSphere (Point Biomedical Corp, San Carlos, CA, USA). The agents were insonified with amplitude-modulated pulses, and it was observed in both agents that a subpopulation of microbubbles did not produce a measurable echo from the first-half amplitude pulse, but did produce a response from the full amplitude pulse and from a subsequent half amplitude pulse. The number of microbubbles in this subpopulation was seen to increase with increasing transmit amplitude. These results do not bear out the simple theory of microbubble-pulse sequence interaction and invite a reassessment of signal processing approaches.

The use of cognitive behavioural therapy techniques for anxiety and depression in hospice patients: a feasibility study

Anxiety and depression are common in palliative care patients. Cognitive behavioural therapy (CBT) has been recommended as one possible treatment, and it has been suggested that non-mental health professionals may be able to treat milder disorders with CBT. The aim of this study was to assess whether the use of CBT techniques in hospice patients is an acceptable intervention, and whether a palliative care professional with short CBT training can usefully apply such techniques. A feasibility study of a brief CBT intervention following training was conducted. Qualitative analysis was carried out on patient feedback from semi-structured interviews. Hospital Anxiety and Depression Scale scores pre-and post-intervention were analysed statistically. Eleven patients completed a short course using CBT techniques. The intervention was acceptable for 10 patients. One patient found it unacceptable due to advanced disease, lethargy and severe depression. Anxiety or depression symptoms were helped in eight patients. This study showed that a palliative care professional with short training in CBT was usefully able to apply CBT techniques to hospice patients with mild-to-moderate anxiety or depression.

Open issues in organizing computer systems conferences

The Workshop on Organizing Workshops, Conferences, and Symposia for Computer Systems (WOWCS) was organized to "bring together conference organizers (past, present, and future) and other interested people to discuss the issues they confront." In conjunction with WOWCS, we survey some previous publications that discuss open issues related to organizing computer systems conferences, especially concerning conduct and management of the review process. We also list some topics about which we wish WOWCS had received submissions, but did not; these could be good topics for future articles.

OpenFlow

This whitepaper proposes OpenFlow: a way for researchers to run experimental protocols in the networks they use every day. OpenFlow is based on an Ethernet switch, with an internal flow-table, and a standardized interface to add and remove flow entries. Our goal is to encourage networking vendors to add OpenFlow to their switch products for deployment in college campus backbones and wiring closets. We believe that OpenFlow is a pragmatic compromise: on one hand, it allows researchers to run experiments on heterogeneous switches in a uniform way at line-rate and with high port-density; while on the other hand, vendors do not need to expose the internal workings of their switches. In addition to allowing researchers to evaluate their ideas in real-world traffic settings, OpenFlow could serve as a useful campus component in proposed large-scale testbeds like GENI. Two buildings at Stanford University will soon run OpenFlow networks, using commercial Ethernet switches and routers. We will work to encourage deployment at other schools; and We encourage you to consider deploying OpenFlow in your university network too

OpenFlow

This whitepaper proposes OpenFlow: a way for researchers to run experimental protocols in the networks they use every day. OpenFlow is based on an Ethernet switch, with an internal flow-table, and a standardized interface to add and remove flow entries. Our goal is to encourage networking vendors to add OpenFlow to their switch products for deployment in college campus backbones and wiring closets. We believe that OpenFlow is a pragmatic compromise: on one hand, it allows researchers to run experiments on heterogeneous switches in a uniform way at line-rate and with high port-density; while on the other hand, vendors do not need to expose the internal workings of their switches. In addition to allowing researchers to evaluate their ideas in real-world traffic settings, OpenFlow could serve as a useful campus component in proposed large-scale testbeds like GENI. Two buildings at Stanford University will soon run OpenFlow networks, using commercial Ethernet switches and routers. We will work to encourage deployment at other schools; and We encourage you to consider deploying OpenFlow in your university network too