A Technology-Informed Approach to Clinical Trial Equity

PURPOSE/OBJECTIVE(S)

Despite efforts to increase participation of diverse communities in clinical trials, ethnic/racial minorities remain underrepresented. One such determinant may be lack of access to a comprehensive cancer center that conducts clinical research. Historically, our institution has had low accrual from rural regions further away from our cancer center, with Hispanic or Latino (HL) patients (pts) being especially underrepresented in our clinical research. In this study, we explored the impact of a clinical trial that allowed pts to receive chemotherapy (chemo) with their local oncologist. We hypothesize that allowing pts to receive chemo locally will lead to higher rates of enrollment from populations under-represented in clinical trials.

MATERIALS/METHODS

We conducted a study for pts with rectal cancer to undergo short-course radiation followed by 4 months of chemo with the option to pursue watch and wait if pts achieve a clinical complete response. Radiation was administered at our institution while pts could receive standard-of-care chemo closer to home with their local oncologist. For pts who received chemo locally, the research coordinator and co-investigators held video visits with the pts prior to each chemo infusion to review adverse events (AE), labs, and chemo dosing. We compared demographic data of pts on this trial with that of pts enrolled across all adult therapeutic oncologic clinical trials over the same time period at our institution. Distance to our institution was calculated based on pts' primary residence zip code. Protocol compliance with AE reporting for pts who received chemo locally was assessed by chart review.

RESULTS

Between May 2020 and January 2023, 24/35 enrolled pts completed both radiation and chemo on trial. 13/24 pts (54%) received chemo locally. Of the 24 pts, 16 were White (67%), 7 Asian (29%), 1 Native Hawaiian/ Pacific Islander (4%). Of all enrolled patients, 4 were HL (16.7%), compared to our institutional average of 16.5%. All enrolled HL pts received their chemo locally. The average distance traveled by non-HL pts from their home to our institution was 87.7 miles (range 5.1 - 308). In contrast, HL pts traveled an average of 147.8 miles (range 110 - 249), 68% further than their non-HL counterparts. There was 100% compliance with AE reporting among those pts who received their chemo locally.

CONCLUSION

Although the percentage of HL participation in our study was consistent with our institutional average, all HL pts enrolled on the trial received treatment locally and lived substantially further from our institution than non-HL. By allowing pts to receive this part of treatment locally, we provided pts who live further away an opportunity to engage in clinical research without the associated financial and time toxicities related with traveling for treatment. By decentralizing clinical trials and leveraging telemedicine, we can promote the participation of under-represented groups in clinical trials.

A challenging case of granulomatosis with polyangiitis with cardiac involvement: a rare case report

Background

Granulomatosis with polyangiitis (GPA), a systemic antineutrophil cytoplasmic antibody (ANCA) associated vasculitis, is characterized by inflammation of the small arteries, arterioles, and capillaries classically manifesting with glomerulonephritis and necrotizing granulomatous lesions of the upper and lower respiratory tract. With an incidence of approximately 12 cases per one million individuals per year it is an uncommon diagnosis that typically presents as frequent pulmonary and sinus infections; however, if left without definitive treatment progresses to more severe manifestations specifically hemoptysis and hematuria.

Case Description

This case report highlights a 15-year-old woman who had both classic and non-classic findings making the diagnosis challenging. Specifically, her age of presentation, improvement with anti-microbials, and coronary dilation were not classic. Additionally, her lab work was negative for the cytoplasmic subset antineutrophil cytoplasmic autoantibody (c-ANCA), but positive for serum anti-proteinase 3 antineutrophil cytoplasmic antibody (PR3-ANCA) which further delayed the ultimate diagnosis as this is typically c-ANCA positive.

Conclusions

Other systemic vasculitides, such as mucocutaneous lymph node disease, are associated with cardiac pathology necessitating further medical management and follow-up to prevent increased morbidity and mortality. Knowing this, we conclude that further evaluation for cardiac pathology would be prudent as part of the initial workup of patients with a diagnosis of GPA. Included is a brief review of available literature on GPA to emphasize the typical presentation, lab findings, and importance of early diagnosis.

Usability evaluation of a non-invasive neutropenia screening device (PointCheck™) for cancer chemotherapy patients: Observational Study (Preprint)

Background

Patients with cancer undergoing cytotoxic chemotherapy face an elevated risk of developing serious infection as a consequence of their treatment, which lowers their white blood cell count and, more specifically, their absolute neutrophil count. This condition is known as neutropenia. Neutropenia accompanied by a fever is referred to as febrile neutropenia, a common side effect of chemotherapy with a high mortality rate. The timely detection of severe neutropenia (<500 absolute neutrophil count/μL) is critical in detecting and managing febrile neutropenia. Current methods rely on blood draws, which limit them to clinical settings and do not allow frequent or portable monitoring. In this study, we demonstrated the usability of PointCheck, a noninvasive device for neutropenia screening, in a simulated home environment without clinical supervision. PointCheck automatically performs microscopy through the skin of the finger to image the blood flowing through superficial microcapillaries and enables the remote monitoring of neutropenia status, without requiring venipuncture.

Objective

This study aimed to evaluate the usability of PointCheck, a noninvasive optical technology for screening severe neutropenia, with the goal of identifying potential user interface, functionality, and design issues from the perspective of untrained users.

Methods

We conducted a multicenter study using quantitative and qualitative approaches to evaluate the usability of PointCheck across 154 untrained participants. We used a mixed method approach to gather usability data through user testing observations, a short-answer qualitative questionnaire, and a standardized quantitative System Usability Scale (SUS) survey to assess perceived usability and satisfaction.

Results

Of the 154 participants, we found that 108 (70.1%) scored above 80.8 on the SUS across all sites, with a mean SUS score of 86.1 across all sites. Furthermore, the SUS results indicated that, out of the 151 users who completed the SUS survey, 145 (96%) found that they learned how to use PointCheck very quickly, and 141 (93.4%) felt very confident when using the device.

Conclusions

We have shown that PointCheck, a novel technology for noninvasive, home-based neutropenia detection, can be safely and effectively operated by first-time users. In a simulated home environment, these users found it easy to use, with a mean SUS score of 86.1, indicating an excellent perception of usability and placing this device within the top tenth percentile of systems evaluated for usability by the SUS.

Trial Registration

ClinicalTrials.gov NCT04448314; https://clinicaltrials.gov/ct2/show/NCT04448314 (Hospital Universitario 12 de Octubre registration) and NCT04448301; https://clinicaltrials.gov/ct2/show/NCT04448301 (Boston Medical Center registration)

Interruptions: Challenges and Innovations in Exhibition-Making

Anthropology and its institutions have come under increased pressure to focus critical attention on the way they produce, steward, and manage cultural knowledge. However, in spite of the discipline’s reflexive turn, many museums remain encumbered by Enlightenment-derived legitimating conventions. Although anthropological critiques and critical museology have not sufficiently disrupted the majority paradigm, certain exhibitionary projects have served to break with established theory and practice. The workshop described in this article takes these nonconforming “interruptions” as a point of departure to consider how paradigm shifts and local museologies can galvanize the museum sector to promote intercultural understanding and dialogue in the context of right-wing populism, systemic racism, and neoliberal culture wars.

Museums in the Pandemic

Throughout human history, the spread of disease has closed borders, restricted civic movement, and fueled fear of the unknown; yet at the same time, it has helped build cultural resilience. On 11 March 2020 the World Health Organization (WHO) classified COVID-19 as a pandemic. The novel zoonotic disease, first reported to the WHO in December 2019, was no longer restricted to Wuhan or to China, as the highly contagious coronavirus had spread to more than 60 countries. The public health message to citizens everywhere was to save lives by staying home; the economic fallout stemming from this sudden rupture of services and the impact on people’s well-being was mindboggling. Around the globe museums, galleries, and popular world heritage sites closed (Associated Press 2020). The Smithsonian Magazine reported that all 19 institutes, including the National Zoo and the National Museum of the American Indian (NMAI), would be closed to the public on 14 March (Daher 2020). On the same day, New Zealand’s borders closed, and the tourism industry, so reliant on international visitors, choked. Museums previously deemed safe havens of society and culture became petri dishes to avoid; local museums first removed toys from their cafés and children’s spaces, then the museum doors closed and staff worked from home. In some cases, front-of-the-house staff were redeployed to support back-of-the-house staff with cataloguing and digitization projects. You could smell fear everywhere.

Borders and Interruptions

While museums are perceived as institutions dedicated to the dissemination and exchange of culturally diverse knowledges, museum scholarship has been hampered by a lack of multilingual networks and publications necessary for the exchange of museological perspectives between different linguistic, regional, and national communities. At the same time, the museum decolonization movement, the move from monocultural to pluricultural societies, the political resurgence of cultural essentialism, escalating environmental deterioration, and the international impact of current migration crises—by both uniting and dividing peoples—have clarified the need for institutions to socially and intellectually engage with the increasingly complex global flows and disruptions of people and ideas.

Evaluation of a new continuous mononuclear cell collection procedure in a single transplant center cohort enriched for AL amyloidosis patients

BACKGROUND

The Spectra Optia continuous mononuclear cell (CMNC) program is newly available, and herein validated in a single-center cohort enriched with AL amyloidosis patients to collect a target CD34+ yield of 2.5 × 10⁶ cells/kg within 2 days.

METHODS

Consecutive autologous transplant patients in 2016 are included. Patients undergo leukapheresis with Optia CMNC and Spectra v4.7 over a 2-day cycle. Data collection includes collection efficiency, adverse events and engraftment kinetics.

RESULTS

36 leukapheresis procedures on 18 patients are included. The diagnoses are AL amyloidosis (9), myeloma (7), lymphoma (2), and scleroderma (1). Median age is 60; 12 are men. Plerixafor was employed pre-emptively in 6 cycles. Median blood CD34+ on Day 1 of leukapheresis was 46 cells/uL. Median number of blood volumes processed on Day 1 was 3.1. All collection cycles were completed within 2 days; only one in a heavily pretreated lymphoma patient did not reach the target requiring a second mobilization attempt. Mean collection efficiencies were comparable between the two devices. There were 2 adverse events: tubing rupture on the Optia; and one case of hypotension. All 18 patients underwent high-dose chemotherapy: median cell dose infused was 7.7 × 10⁶ CD34+ cells/kg. Median days to neutrophil and platelet engraftment were 10 and 13 respectively.

CONCLUSION

The Optia CMNC collection protocol is safe and effective in a small single-center autologous stem cell transplant cohort enriched for high-risk patients with AL amyloidosis and cardiac involvement. Caution is needed for tubing setup because there is less cumulative experience with Optia.

Elastomeric Valves, a New Design

The convex bileaflet valve replaces the flat biflap inflow valve designed by Long Sheng Yu and the tricusp semilunair outflow valve. One reason is easier manufacturing. Convex bileaflet valves are developed for the 11, 20, 40, 70 and 140cc ventricles. Testing included curves (Cardiac Output versus Venous Pressure, Cardiac Output versus Heart rate), flow visualization studies, paint and bloodbag studies. The curves and flow visualization were done by connecting ventricles to one of our standard mock circulations. Paint and bloodbag studies were done by connecting the hearts to a bloodbag, but the bag was filled with water for the paint studies. The curves show high cardiac output, even with pumping at high heart rates (150 BPM+). The flow visualization shows a good stream through the sinus Valsalvae. No stagnating flow is visible. The bloodbag studies which provoke thrombosis show it on the edges of the heart valves, and little in the groove between the valve and the sinus Valsalvae. Heparninzation prevents the thrombosis. Results of our tests were good. The convex bileaflet valve seems to have good future.

Single agent lenalidomide three times a week induces hematologic responses in AL amyloidosis patients on dialysis

The combination of lenalidomide and dexamethasone can produce hematologic responses in previously treated patients with AL amyloidosis. Because lenalidomide is primarily excreted unchanged by the kidney, adjustments to the starting dose of lenalidomide are recommended to provide appropriate drug exposure in patients with moderate or severe renal impairment and in patients on dialysis. Here, we report on a study of patients with AL amyloidosis on dialysis treated with lenalidomide at a dose of 10 mg orally three times a week. Seven patients were enrolled. All patients had received prior treatment, with 57% receiving prior high-dose melphalan and stem cell transplantation. Two patients died before evaluation of response. The most common adverse event was infection; no thromboembolic complications were seen. One patient required dose-modification. Hematologic responses were obtained by four of the five evaluable patients. Median overall survival was 18 months. In conclusion, adjusted dose lenalidomide was reasonably tolerated and induced sustained hematologic responses in previously treated patients with AL amyloidosis on dialysis.

Audit of co-management and critical care outreach for high risk postoperative patients (The POST audit)

Co-management and critical care outreach for high risk surgical patients have been proposed to decrease postoperative complications and mortality. We proposed that a clinical project with postoperative comanagement and critical care outreach, the Post Operative Surveillance Team: (POST), would be associated with decreased hospital length of stay. We conducted a retrospective before (control group) and after (POST group) audit of this hospital program. POST was staffed for four months in 2010 by two intensive care nurses and two senior registrars who conducted daily ward rounds for the first five postoperative days on high risk patients undergoing inpatient general or urological surgery. The primary endpoint was length of hospital stay and secondary endpoints were Medical Emergency Team (MET) calls, cardiac arrests and in-hospital mortality. There were 194 patients in the POST group and 1,185 in the control group. The length of stay in the POST group, median nine days (Inter-quartile range [IQR]: 5 to 17 days), was longer than the control group, median seven days (IQR: 4 to 13 days): difference two days longer (95.0% confidence interval [95.0% CI]: 1 to 3 days longer, P <0.001). There were no important differences in the proportion of patients having MET calls (16.0% POST versus. 13% control (P=0.25)) or mortality (2.1% POST versus 2.8% Control (P=0.82)). Our audit found that the POST service was not associated with reduced length of stay. Models of co-management, different to POST, or with different performance metrics, could be tested.

Field-evolved resistance: assessing the problem and ways to move forward

"Field-evolved resistance" is defined as a "genetically based decrease in susceptibility of a population to a toxin caused by exposure to the toxin in the field." The key component of "field-evolved" resistance is that it does confer decreased susceptibility to an insecticide in the field. Another key component is that the decrease in susceptibility to the insecticide is because of previous exposure of the target insect to the toxin in the field. Several studies have reported field-evolved resistance to crops engineered to express proteins from the bacterium, Bacillus thuringiensis (Bt). However, there has not been a consistent standard in the application of the definition of field-evolved resistance for Bt crops. The inconsistency in applying the definition arises from differences in the methods used to detect resistance, the ecology of the interaction between the pest and the Bt crop, and the effective dose the pest encounters while feeding on the Bt crop. Using case studies of reported resistance to Bt crops, it is demonstrated resistance does not come in a single form, and that in most cases, resistance can still be managed.

Critical Museology

Synthesizing work carried out by the author over the past twenty-five years, this article proposes a tentative disciplinary definition of critical museology, distinguishing its related methodological interdictions and describing its distinctiveness from what is here defined as operational museology. The article acknowledges the diverse intellectual sources that have informed the subject and calls for a reorientation and separation of critical museology from the operational museologies that form part of its area of study. Critical museology, it is argued, is not only an essential intellectual tool for better understanding museums, related exhibitionary institutions, fields of patrimony and counter patrimonies, and the global and local flows and conditions in which they are embedded, but is also crucial for developing new exhibitionary genres, telling untold stories, rearticulating knowledge systems for public dissemination, reimagining organizational and management structures, and repurposing museums and galleries in line with multicultural and intercultural states and communities.

High-dose melphalan and autologous stem cell transplantation for AL amyloidosis: recent trends in treatment-related mortality and 1-year survival at a single institution

Treatment with high-dose melphalan chemotherapy supported by hematopoietic rescue with autologous stem cells produces high rates of hematologic responses and improvement in survival and organ function for patients with AL amyloidosis. Ongoing clinical trials explore pre-transplant induction regimens, post-transplant consolidation or maintenance approaches, and compare transplant to non-transplant regimens. To put these studies into context, we reviewed our recent experience with transplant for AL amyloidosis in the Amyloid Treatment and Research Program at Boston Medical Center and Boston University School of Medicine. Over the past 10 years, there was a steady reduction in rates of treatment-related mortality and improvement in 1-year survival, now approximately 5% and 90%, respectively, based upon an intention-to-treat analysis. Median overall survival of patients treated with this approach at our center exceeds 7.5 years.

Insect-resistant genetically modified rice in China: from research to commercialization

From the first insect-resistant genetically modified (IRGM) rice transformation in 1989 in China to October 2009 when the Chinese Ministry of Agriculture issued biosafety certificates for commercial production of two cry1Ab/Ac Bacillus thuringiensis (Bt) lines, China made a great leap forward from IRGM rice basic research to potential commercialization of the world's first IRGM rice. Research has been conducted on developing IRGM rice, assessing its environmental and food safety impacts, and evaluating its socioeconomic consequences. Laboratory and field tests have confirmed that these two Bt rice lines can provide effective and economic control of the lepidopteran complex on rice with less risk to the environment than present practices. Commercializing these Bt plants, while developing other GM plants that address the broader complex of insects and other pests, will need to be done within a comprehensive integrated pest management program to ensure the food security of China and the world.

Kidney dysfunction during lenalidomide treatment for AL amyloidosis

BACKGROUND

Lenalidomide is an immunomodulatory agent used to treat plasma cell dyscrasias. We previously observed worsening of kidney function in a high proportion of patients with AL amyloidosis during lenalidomide treatment. The objective of this study is to characterize alterations in kidney function among patients with AL amyloidosis undergoing treatment with lenalidomide.

METHODS

This is a secondary analysis of an ongoing clinical trial at a single referral centre. Forty-one patients with AL amyloidosis received lenalidomide with or without dexamethasone in monthly cycles. Kidney dysfunction was defined as ≥ 50% increase in serum creatinine. Severe kidney dysfunction was defined as ≥ 100% increase in serum creatinine. Recovery of renal function was defined as a return of serum creatinine to within 25% of the pre-treatment value or discontinuation of dialysis.

RESULTS

Twenty-seven of 41 patients (66%) developed kidney dysfunction during lenalidomide treatment. The kidney dysfunction was severe in 13 of these patients (32%); four of whom required initiation of dialysis (10%). The median time to kidney dysfunction after starting lenalidomide was 44 days (interquartile range 15-108 days). Four of eight patients without underlying renal amyloidosis developed kidney dysfunction. Patients with severe kidney dysfunction were older and had a higher frequency of underlying renal amyloidosis, greater urinary protein excretion, and lower serum albumin. Recovery of renal function occurred in 12 patients (44%).

CONCLUSIONS

Among patients with AL amyloidosis, worsening of kidney function occurs frequently during lenalidomide treatment. While a causal role of the drug has not been established, our findings suggest that kidney function should be monitored closely during treatment with this drug.

Pathological response after chemoradiation for T3 rectal cancer

OBJECTIVE

The aim of this study was to investigate the effect of preoperative chemoradiotherapy (CRT) on nodal disease in locally advanced rectal adenocarcinoma.

METHOD

Thirty-two patients staged uT3N0 and 27 patients staged uT3N1 rectal adenocarcinoma who underwent pre-CRT staging using endoscopic ultrasound or rectal protocol CT were included. The median radiation dose was 50.4 Gy (range: 45-50.4 Gy) at 1.8 Gy per fraction and all patients received concurrent 5-FU or capecitabine-based chemotherapy. Low anterior resection or abdomino-perineal resection occurred at a median of 46 days (range: 27-112 days) after CRT.

RESULTS

Eleven of 32 uT3N0 patients (34.4%) and 13 of 26 uT3N1 patients (50.0%) had ypN+ (P = 0.29). For patients with uT3N0, 10 of 20 (50.0%) with ypT2-3 and 1 of 12 (8.3%) with ypT0-1 were ypN+ (P = 0.02). For patients with uT3N1, 12 of 20 (60.0%) with ypT2-3 and 1 of 6 (16.7%) with ypT0-1 were ypN+ (P = 0.16). Overall, the ypN+ rate was 11.1% in the ypT0-yT1 group compared with 55.0% in the ypT2-yT3 group (P = 003). Among patients with uT3N0 disease, the ypN+ rate in patients who had surgery > 46 days vs<or= 46 days was 7.1%vs 55.6% (P = 0.01) respectively. Among patients with uT3N1 disease, the ypN+ rate in patients who had surgery > 46 days vs<or= 46 days was 54.5%vs 46.7%, (P = 0.99) respectively. Overall, the ypN+ rate in patients who had surgery > 46 days vs<or= 46 days was 28.0%vs 51.5% (P = 0.11).

CONCLUSIONS

The risk of residual nodal disease after CRT is significant. Primary tumour response is associated with nodal response.

Effect of pre-stress on the yield and flow of En 25 steel

Combined tension-torsion tests have been performed at constant stress ratios on En 25 steel, previously annealed and then subjected to a pre-stress in either tension or torsion.

The post-yield behaviour showed marked room-temperature creep and, in general, both the axial- and the shear-strain components could be expressed by the logarithmic creep equation. The direction of the incremental strain-ratio vector was initially markedly different from that shown in the previous tests on annealed En 25 steel, but rotated towards that direction with increased stress. The yield locus subsequent to each pre-stress was established by fulfilling two requirements: that it must pass through the stress space normal to all the plastic-strain-increment vectors it encounters; that each yield stress should be an extrapolation from the curves of creep coefficient plotted against stress and stress plotted against ‘long time’ strain.

The results show that a pre-stress hardens the material over that half of biaxial stress space bisected by the pre-stress axis and hardens it less or even softens it in the reverse half of that space. The cross-effect of a tensile pre-stress is greater than that of a torsion pre-stress and increasing the degree of pre-stress has a gradually reducing cross-effect.

Yield and subsequent flow behaviour of some annealed steels under combined stress

Constant-stress-ratio tests under combined tension-torsion have been performed on annealed En 25 and En 24 steels. The sharp yield behaviour of these materials enabled the initial yield locus to be clearly defined and this was close to that predicted by the Tresca criterion. Post-yield behaviour showed marked room-temperature creep of the logarithmic form ∊ = a ln t+ c, by both the axial- and shear-strain components. The strain-rate ratios and the strain ratios were normal to the yield locus and remained so for increasing stress.

The equivalent-plastic-work hypothesis did not produce satisfactory correlation of the combined-stress results and empirical equivalence of the strains was established by introducing a factor to account for the influence of combined stresses upon the magnitude of the resulting strains. This empirical equivalence also provided good correlation of the creep-strain rates and these results finally led to the complete correlation of the stress-strain-time behaviour of these materials at room temperature.

The Anisotropic Yield, Flow and Creep Behaviour of Pre-Strained En24 Steel

Tests under combinations of tension, torsion and internal pressure have been performed at constant stress ratio on En24 steel, previously annealed, and then subjected to a pre-stress in either axial or circumferential tension or torsion. Post-yield behaviour showed marked room-temperature creep by all strain components in the logarithmic form ε = a In t + c. The initial direction of the incremental plastic strain-ratio vector was markedly different from isotropic behaviour and remained constant in direction with time. Increased loading resulted in a progressive rotation towards the isotropic direction. Anisotropic yield loci were established from the normality rule and from the backward extrapolation of curves of creep coefficient versus stress and stress versus ‘long-time’ strain.

The yield locus was translated to the pre-stress point and this local work-hardening was accompanied by softening in both the transverse and reverse directions, i.e. the cross-effect and Bauschinger effect respectively. Yield loci in planes not containing the pre-stress axis showed softening in all directions and under axial tension-internal pressure the cross-effect caused a rotation of the locus. All yield loci were smooth and continuous.

Yield criteria derived from the theories of Edelman and Drucker and also Williams and Svensson were in good agreement with experiment over the whole locus. Hill's theory was thought to be more appropriate to material behaviour following large deformations.

Recurrent infection and catheter loss in patients on continuous ambulatory peritoneal dialysis

OBJECTIVE

To elucidate the factors leading to catheter loss from recurrent infection in patients on continuous ambulatory peritoneal dialysis (CAPD).

DESIGN

All catheters removed from patients were prospectively examined for infection.

SETTING

CAPD unit in large tertiary-care general hospital.

PATIENTS

Sixty-five consecutive patients undergoing catheter removal for whatever cause; 20 catheters rejected because of desiccation or contamination in transit.

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

Micro-organisms linked to catheter removal; their locations on removed catheters.

RESULTS

Of 45 catheters removed between January 1994 and August 1995, 26 were infected: 13/26 infections were caused by Staphylococcus aureus and 7/26 by Pseudomonas aeruginosa. In only one case was S. epidermidis associated with catheter removal. The most striking finding was that the inner cuff harbored large numbers of the infecting organisms, even when antibiotics had eradicated them from the peritoneal cavity and exit site, where present, and the catheter lumen.

CONCLUSION

The importance of S. aureus and Ps. aeruginosa rather than S. epidermidis in catheter loss due to relapsing infection is confirmed. Persistence of the causative organisms in the inner cuff is a likely explanation for relapse after treatment, and might be due to the predominantly intraperitoneal administration of antibiotics. A clinical trial of the effect on catheter retention of empirical use of systemic or oral agents that give high tissue levels and are active against intracellular micro-organisms, along with recommended intraperitoneal regimens, is indicated.

Elastomeric valves, a new design

The convex bileaflet valve replaces the flat biflap inflow valve designed by Long Sheng Yu and the tricusp semilunair outflow valve. One reason is easier manufacturing. Convex bileaflet valves are developed for the 11, 20, 40, 70 and 140cc ventricles. Testing included curves (Cardiac Output versus Venous Pressure, Cardiac Output versus Heart rate), flow visualization studies, paint and bloodbag studies. The curves and flow visualization were done by connecting ventricles to one of our standard mock circulations. Paint and bloodbag studies were done by connecting the hearts to a bloodbag, but the bag was filled with water for the paint studies. The curves show high cardiac output, even with pumping at high heart rates (150 BPM+). The flow visualization shows a good stream through the sinus Valsalvae. No stagnating flow is visible. The bloodbag studies which provoke thrombosis show it on the edges of the heart valves, and little in the groove between the valve and the sinus Valsalvae. Heparninzation prevents the thrombosis. Results of our tests were good. The convex bileaflet valve seems to have good future.

The development of a valveless cardiac assist device attached to the ventricular apex

Konstantinov et al, in October, 1991, published a novel way to bridge a patient for heart transplantation. They proposed to cut off both ventricles high under the atrioventricular groove, leaving the atria, aorta, and pulmonary artery and their valves intact and to attach pneumatically driven, valveless pulsating pouches to assist the heart until a donor could be found. The removal of the ventricles just below the atrioventricular groove is called the "high cut"; it, however, destroys the chordae tendineae rendering the mitral and tricuspid valves insufficient. These have to be replaced by tissue inflow valves. We chose to cut off the ventricles at a lower level (the "low cut") to leave the papillary muscles on both sides intact, thereby saving the integrity of the mitral and tricuspid valves. Pulsating pouches were made to fit the heart at this lower level. They can be easily connected to the remaining heart after a specially disigned cuff has been sutured over the ventricular stumps. The pouches were pumped during the systole of the natural heart, but the myocardium may have to be electrically stimulated during systole to prevent undue distension. If the turgor is too weak to prevent distension, a sleeve over the ventricles is provided. To find the best location for these pouches, human cadaver implantations were done and the pre peritoneal cavity was found to be the most suitable. In vitro testing to determine how much flow could be pumped was done by attaching the pouches to fresh pig hearts and connecting them to a double sided mock circulation.(ABSTRACT TRUNCATED AT 250 WORDS)

The response of Escherichia coli to ciprofloxacin and norfloxacin

The action of ciprofloxacin and norfloxacin on two strains of Escherichia coli was studied by diverse methods including electronmicroscopy, viable counting and continuous turbidimetric monitoring. During the first few hours of exposure to inhibitory concentrations of the drugs, the opacity of bacterial cultures continued to increase for a period that was inversely proportional to the drug concentration. This change corresponded to the appearance of filamentous bacteria, swollen forms and some lysis. There was subsequently a gradual drop in opacity during which extensive lysis occurred. As judged by viable counts of bacteria washed free of drug, cell death occurred within 30 min of first exposure to the drugs and continued over a 3-h period. Ultrastructure studies demonstrated that lysis was preceded by the formation of vacuoles, predominantly at the poles of the cells. At these sites, breaks in the cell walls eventually occurred, resulting in extrusion of the cytoplasmic contents.

Increased urine histamine and contrast media reactions

Urine samples were collected from 200 subjects undergoing intravenous pyelography. The urine histamine levels were compared with those of 132 normal control subjects, 11 subjects with systemic mastocytosis, six subjects with idiopathic anaphylaxis, and ten subjects experiencing mild anaphylactic reactions during allergy immunotherapy. Compared with normal controls, as a group, all subjects receiving intravenous contrast media had increased urine histamine (P less than 0.05 by Student's t-test) while those subjects experiencing adverse reactions had considerably larger increases. The urine histamine levels in the subjects experiencing systemic reactions were in the same range as those observed in patients having mild anaphylactic reactions to immunotherapy and somewhat lower than those found in idiopathic anaphylaxis or systemic mastocytosis. These data suggest that some histamine release accompanies infusions of contrast media in all subjects and that larger amounts of histamine release are associated with adverse reactions.