The Lateral Continuity and Vertical Arrangement of Dust Layers in the Martian North Polar Cap From SHARAD Multiband Data

Interpretation of radar sounder reflections to infer the structure and composition of the martian polar caps depends on whether bright returns correspond to single packed dust layers or a more finely layered structure. Reflections from multiple layers can create strong resonant scattering (interference) effects that impact analyses of radargram reflectors and inference of dielectric contrast. We identify resonant behavior for an areally extensive reflector in the north polar layered deposits from Shallow Radar data processed in two frequency bands. Echo strength varies by ∼2 dB between subband reflections across a region ∼400 km in extent, with the stronger echo shifting abruptly from the high- to low-frequency band outside the central region of Gemina Lingula. This behavior can arise from resonant scattering between two layers of dust (0.3-0.6 m thick) separated by 0.5-3 m of ice. Such layering requires there be little postdepositional aeolian activity to preserve layer thickness and spacing.

Diagnosis, management and follow up of peripheral T cell lymphomas: A Consensus Practice Statement from the Australasian Lymphoma Alliance

Peripheral T-cell lymphomas (PTCLs) represent a heterogeneous disease group accounting for 10% of non-Hodgkin lymphomas. PTCL patients have typically poorer outcomes compared to aggressive B-cell lymphomas. However, such outcomes are heavily dependent upon subtype. Although anthracycline-based regimens such as cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) remain the standard first-line treatment for most aggressive PTCLs, there are important variations including incorporation of novel agents, use of radiotherapy and judicious consideration of stem cell transplantation. Relapsed or refractory disease represents a significant area of unmet need where chemotherapy intensification has limited efficacy and novel agents such as brentuximab vedotin and pralatrexate provide additional opportunities for attainment of remission and potential stem cell transplant. In the future, pre-therapy prognostic biomarkers including genomic characterisation, may aid in risk stratification and help guide initial patient management to improve survival. There is an urgent need to better understand the pathogenesis of PTCLs to facilitate novel drug combinatorial approaches to improve survival. This position statement represents an evidence-based synthesis of the literature for application in Australian and New Zealand practice. This article is protected by copyright. All rights reserved.

Diffuse large B-cell lymphoma: A consensus practice statement from the Australasian Lymphoma Alliance

Diffuse large B-cell lymphoma (DLBCL) is the most common lymphoma subtype, accounting for 30-40% of lymphoma diagnoses. Though aggressive, cure is achievable in approximately 60% of cases with primary chemo-immunotherapy, and in a further substantial minority by salvage therapy and autologous stem cell transplantation. Despite promising activity in early phase clinical trials, no intensified or novel treatment regimen has improved outcomes over R-CHOP21 in randomised studies. However, there remain several areas of controversy including the most appropriate prognostic markers, CNS prophylaxis and the optimal treatment for patients with high-risk disease. This position statement presents an evidence-based synthesis of the literature for application in Australasian practice. This article is protected by copyright. All rights reserved.

Evaluation of the Impact of Magnetic Resonance Imaging with Susceptibility-weighted Imaging for Screening and Surveillance of Radiation-induced Cavernomas in Long-term Survivors of Malignancy

AIMS

Radiation-induced cavernomas (RIC) are common late toxicities in long-term survivors of malignancy following cerebral irradiation. However, the natural history of RIC is poorly described. We report the first series of long-term surveillance of RIC using modern magnetic resonance imaging (MRI) including highly sensitive susceptibility-weighted imaging (SWI). The aims of this research were to better characterise the natural history of RIC and investigate the utility of MRI-SWI for screening and surveillance.

MATERIALS AND METHODS

Eligibility required long-term survivors of malignancy with previous exposure to cerebral irradiation and RIC identified on MRI-SWI surveillance. The number and size of RIC were reported on Baseline MRI-SWI and last Follow-up MRI-SWI.

RESULTS

In total, 113 long-term survivors with RIC underwent MRI-SWI surveillance; 109 (96%) were asymptomatic at the time of RIC diagnosis. The median age at cerebral irradiation was 9.3 years; the median radiotherapy dose was 50.4 Gy. The median time from cerebral irradiation to Baseline MRI-SWI was 17.9 years. On Baseline MRI-SWI, RIC multiplicity was present in 89% of patients; 34% had >10 RIC; 65% had RIC ≥4 mm. The median follow-up from Baseline MRI-SWI was 7.3 years. On Follow-up MRI-SWI, 96% of patients had multiple RIC; 62% had >10 RIC; 72% had RIC ≥4 mm. Of the 109 asymptomatic patients at RIC diagnosis, 96% remained free from RIC-related symptoms at 10 years. Only two required neurosurgical intervention for RIC; there was no RIC-related mortality.

CONCLUSIONS

RIC are commonly multiple, asymptomatic and typically increase in size and number over time. Our findings suggest that MRI-SWI for screening of RIC is unlikely to influence longer term intervention in asymptomatic cancer survivors. In the absence of neurological symptoms, assessment or monitoring of RIC are insufficient indications for MRI-SWI surveillance for long-term survivors of malignancy with past exposure to cerebral irradiation.

In pursuit of equity: partnering to improve breast and prostate cancer outcomes among African Americans

PURPOSE

Community-based participatory research (CBPR) is a collaborative partnership approach that leverages the strengths of academic-community groups to address local problems. CBPR emphasizes equity (e.g., co-learning, power-sharing, participatory decision-making) among groups to achieve goals and promote sustainability. This study examines group dynamics, and their influence on achieving shared goals, within a CBPR-guided partnership established to improve breast and prostate cancer outcomes among underserved African American communities in St. Louis, Missouri.

METHODS

We conducted in-person, semi-structured interviews with key academic and community informants and surveyed via email community collaborators involved in outreach activities. Interviews were audiotaped, transcribed, and independently coded by two authors using an iterative, open-coding process to identify major themes. Surveys were summarized using similar coding criteria for open-ended responses and descriptive statistics for discrete responses. Using a grounded theory approach, we summarized and compared themes from each data source to identify similarities and differences and triangulated results to generate overarching thematic findings.

RESULTS

Participants described benefits from the partnership (funding; clinical, public health and evaluation expertise; training and networking opportunities) and found beneficial ways to leverage the partners' strengths in collaborating Participants expressed long-term commitment to sustaining the partnership and building capacity to address cancer disparities, but faced challenges related to power-sharing and participatory decision-making.

CONCLUSIONS

Using CBPR to address cancer disparities is an effective approach to capacity-building and achieving shared goals. By evaluating the structures and processes within CBPR collaborations through the lens of equity, partners may identify and address challenges that threaten long-term partnership sustainability.

Long-term Survival with 18-Fluorodeoxyglucose Positron Emission Tomography-directed Therapy in Non-small Cell Lung Cancer with Synchronous Solitary Brain Metastasis

AIMS

At diagnosis, <1% of patients with non-small cell lung cancer (NSCLC) have synchronous solitary brain metastasis (SSBM). In prior cohorts without 18-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) staging, definitive treatment to intracranial and intrathoracic disease showed a 5-year overall survival (OS) of 11-21%. We investigated the long-term survival outcomes for patients with SSBM NSCLC, diagnosed in the FDG-PET/CT era and treated definitively with local therapies to both intracranial and intrathoracic sites of disease.

MATERIALS AND METHODS

This retrospective study assessed patients staged with FDG-PET/CT who received definitive lung and SSBM treatment from February 1999 to December 2017. A lung-molecular graded prognostic assessment (lung-molGPA) score was assigned for each patient using age, performance status score, and, where carried out, molecular status. Overall survival and progression-free survival (PFS) were calculated using Kaplan-Meier methods. Cox proportional hazard models determined OS and PFS prognostic factors.

RESULTS

Forty-nine patients newly diagnosed with NSCLC and SSBM had a median age of 63 years (range 34-76). The median follow-up of all patients was 3.9 years. Thirty-three patients (67%) had ≥T2 disease, 23 (47%) had ≥N2. At 2 years, 45% of first failures were intracranial only (95% confidence interval 30-59). At 3 and 5 years, OS was 45% (95% confidence interval 32-63) and 30% (95% confidence interval 18-51), respectively. In ≥N1 disease, 5-year OS was 34% (95% confidence interval 18-63). The 3- and 5-year PFS was 8% (95% confidence interval 3-22) and 0%, respectively. Higher lung-molGPA was associated with longer OS (hazard ratio 0.26, 95% confidence interval 0.11-0.61, P = 0.002). Higher lung-molGPA (hazard ratio 0.33, 95% confidence interval 0.15-0.71, P = 0.005) and lower N-stage (hazard ratio 1.56, 95% confidence interval 1.13-2.15, P = 0.007) were associated with longer PFS.

CONCLUSIONS

Definitive treatment of patients with NSCLC and SSBM staged with FDG-PET/CT can result in 5-year survivors, including those with ≥N1 disease.

Three-dimensional radar imaging of structures and craters in the Martian polar caps

Over the last decade, observations acquired by the Shallow Radar (SHARAD) sounder on individual passes of the Mars Reconnaissance Orbiter have revealed the internal structure of the Martian polar caps and provided new insights into the formation of the icy layers within and their relationship to climate. However, a complete picture of the cap interiors has been hampered by interfering reflections from off-nadir surface features and signal losses associated with sloping structures and scattering. Foss et al. (2017) addressed these limitations by assembling three-dimensional data volumes of SHARAD observations from thousands of orbital passes over each polar region and applying geometric corrections simultaneously. The radar volumes provide unprecedented views of subsurface features, readily imaging structures previously inferred from time-intensive manual analysis of single-orbit data (e.g., trough-bounding surfaces, a buried chasma, and a basal unit in the north, massive carbon-dioxide ice deposits and discontinuous layered sequences in the south). Our new mapping of the carbon-dioxide deposits yields a volume of 16,500 km³, 11% larger than the prior estimate. In addition, the radar volumes newly reveal other structures, including what appear to be buried impact craters with no surface expression. Our first assessment of 21 apparent craters at the base of the north polar layered deposits suggests a Hesperian age for the substrate, consistent with that of the surrounding plains as determined from statistics of surface cratering rates. Planned mapping of similar features throughout both polar volumes may provide new constraints on the age of the icy layered deposits. The radar volumes also provide new topographic data between the highest latitudes observed by the Mars Orbiter Laser Altimeter and those observed by SHARAD. In general, mapping of features in these radar volumes is placing new constraints on the nature and evolution of the polar deposits and associated climate changes.

3-D Imaging of Mars' Polar Ice Caps Using Orbital Radar Data

Since its arrival in early 2006, various instruments aboard NASA's Mars Reconnaissance Orbiter (MRO) have been collecting a variety of scientific and engineering data from orbit around Mars. Among these is the SHAllow RADar (SHARAD) instrument, supplied by Agenzia Spaziale Italiana (ASI) and designed for subsurface sounding in the 15-25 MHz frequency band. As of this writing, MRO has completed over 46,000 nearly polar orbits of Mars, 30% of which have included active SHARAD data collection. By 2009, a sufficient density of SHARAD coverage had been obtained over the polar regions to support 3-D processing and analysis of the data. Using tools and techniques commonly employed in terrestrial seismic data processing, we have processed subsets of the resulting collection of SHARAD observations covering the north and south polar regions as SHARAD 3-D volumes, imaging the interiors of the north and south polar ice caps known, respectively, as Planum Boreum and Planum Australe. After overcoming a series of challenges revealed during the 3-D processing and analysis, a completed Planum Boreum 3-D volume is currently being used for scientific research. Lessons learned in the northern work fed forward into our 3-D processing and analysis of the Planum Australe 3-D volume, currently under way. We discuss our experiences with these projects and present results and scientific insights stemming from these efforts.

Pyroclastic Flow Deposits on Venus as Indicators of Renewed Magmatic Activity

Radar-bright deposits on Venus that have diffuse margins suggest eruptions that distribute debris over large areas due to ground-hugging flows from plume collapse. We examine deposits in Eastern Eistla, Western Eistla, Phoebe, and Dione Regiones using Magellan data and Earth-based radar maps. The radar-bright units have no marginal lobes or other features consistent with viscous flow. Their morphology, radar echo strength, polarization properties, and microwave emissivity are consistent with mantling deposits comprised of few-cm or larger clasts. This debris traveled downhill up to ~100 km on modest slopes, and blanketed lava flows and tectonic features to depths of tens of cm to a few meters over areas up to 40×10³ km². There is evidence for ongoing removal and exhumation of previously buried terrain. A newly identified occurrence is associated with a ridge belt south of Ushas Mons. We also note radar-bright streaks of coarse material west of Rona Chasma that reflect the last traces of a deposit mobilized by winds from the formation of Mirabeau crater. If the radar-bright units originate by collapse of eruption columns, with coarse fragmental material entrained and fluidized by hot gases, then their extent suggests large erupted volatile (CO₂ or H₂O) amounts. We propose that these deposits reflect the early stage of renewed magmatic activity, with volatile-rich, disrupted magma escaping through vents in fractured regions of the upper crust. Rapidly eroding under Venus surface conditions, or buried by subsequent eruptions, these markers of recently renewed activity have disappeared from older regions.

Racist or Racial Voting in the 1981 Atlanta Municipal Elections

Some recent municipal elections have been interpreted as indicating that America's cities are becoming more polarized on the dimension of race. It has been hypothesized that the results observed in Atlanta in 1981 and Chicago in 1983 presage an era of voting along racial lines. This article advances an alternative hypothesis: Voters who support candidates of their own race often do so simply because they have no particular reason not to. Specifically, there may be no issue-based reason to cross racial lines. Using both precinct-level and survey data from the 1981 Atlanta municipal elections, the analysis estimates the levels of racial voting (the coincidence of a racial tie between voter and candidate), racist voting (the vote for a candidate of one's own race when an issue-based motive exists to support a candidate of the opposite race), and crossover voting.

3D reconstruction of the source and scale of buried young flood channels on Mars

Outflow channels on Mars are interpreted as the product of gigantic floods due to the catastrophic eruption of groundwater that may also have initiated episodes of climate change. Marte Vallis, the largest of the young martian outflow channels (<500 million years old), is embayed by lava flows that hinder detailed studies and comparisons with older channel systems. Understanding Marte Vallis is essential to our assessment of recent Mars hydrologic activity during a period otherwise considered to be cold and dry. Using data from the Shallow Radar sounder on the Mars Reconnaissance Orbiter, we present a three-dimensional (3D) reconstruction of buried channels on Mars and provide estimates of paleohydrologic parameters. Our work shows that Cerberus Fossae provided the waters that carved Marte Vallis, and it extended an additional 180 kilometers to the east before the emplacement of the younger lava flows. We identified two stages of channel incision and determined that channel depths were more than twice those of previous estimates.

Incidence of transformation to aggressive lymphoma in limited-stage follicular lymphoma treated with radiotherapy

BACKGROUND

The established treatment of limited-stage follicular lymphoma is radiotherapy (RT). There is an inherent risk of transformation of follicular lymphoma to aggressive lymphoma; however, the frequency and impact on the outcome are unknown in limited-stage patients.

MATERIALS AND METHODS

We identified 237 patients with limited-stage follicular lymphoma treated with curative intent RT. Cases were reviewed to determine the frequency of transformation and subsequent survival.

RESULTS

With a median follow-up of 7.4 years, the 10-year risk of transformation was 18.5%. With a median follow-up after transformation of 4.7 years, the 3-year post-transformation progression-free survival (PFS) and overall survival (OS) were 42% and 44%, respectively. The addition of rituximab improved the 3-year post-transformation PFS and OS compared with combination chemotherapy alone (78% versus 15%, P < 0.00001) and (87% versus 38.5%, P < 0.00001), respectively. In multivariate analysis, only rituximab was associated with OS [HR 0.07 (95% CI 0.015-0.312, P = 0.001)] and PFS [HR 0.19 (95% CI 0.55-0.626, P = 0.007)] following transformation.

CONCLUSIONS

There is a moderate risk of transformation in limited-stage follicular lymphoma treated with curative intent RT, and it substantially impacts outcome in these patients. Treatment with rituximab at the time of transformation appears to improve survival in this otherwise poor-risk population.

Minimising critical organ irradiation in limited stage Hodgkin lymphoma: a dosimetric study of the benefit of involved node radiotherapy

BACKGROUND

Chemotherapy plus radiotherapy is the standard of care for patients with limited stage Hodgkin lymphoma (HL). Radiotherapy is evolving from involved field radiotherapy (IFRT) to involved node radiotherapy (INRT) to decrease radiotherapy-related morbidity. In the absence of long-term toxicity data, dose-volume metrics of organs at risk (OAR) provide a surrogate measure of toxicity risk.

PATIENTS AND METHODS

Ten female patients with stage I-IIA supradiaphragmatic HL were randomly selected. All patients had pre-chemotherapy computerised tomography (CT) and CT-positron emission tomography staging. Using CT planning, three radiotherapy plans were produced per patient: (i) IFRT, (ii) INRT using parallel-opposed beams and (iii) INRT using volumetric modulated arc therapy (VMAT). Radiotherapy dose was 30.6 Gy in 1.8 Gy fractions. OAR evaluated were lungs, breasts, thyroid, heart and coronary arteries.

RESULTS

Compared with IFRT, INRT significantly reduced mean doses to lungs (P < 0.01), breasts (P < 0.01), thyroid (P < 0.01) and heart (P < 0.01), on Wilcoxon testing. Compared with conventional INRT, VMAT improved dose conformality but increased low-dose radiation exposure to lungs and breasts. VMAT reduced the heart volume receiving 30 Gy (V30) by 85%.

CONCLUSIONS

Reduction from IFRT to INRT decreased the volumes of lungs, breasts and thyroid receiving high-dose radiation, suggesting the potential to reduce long-term second malignancy risks. VMAT may be useful for patients with pre-existing heart disease by minimising further cardiac toxicity risks.

Mars north polar deposits: stratigraphy, age, and geodynamical response

The Shallow Radar (SHARAD) on the Mars Reconnaissance Orbiter has imaged the internal stratigraphy of the north polar layered deposits of Mars. Radar reflections within the deposits reveal a laterally continuous deposition of layers, which typically consist of four packets of finely spaced reflectors separated by homogeneous interpacket regions of nearly pure ice. The packet/interpacket structure can be explained by approximately million-year periodicities in Mars' obliquity or orbital eccentricity. The observed approximately 100-meter maximum deflection of the underlying substrate in response to the ice load implies that the present-day thickness of an equilibrium elastic lithosphere is greater than 300 kilometers. Alternatively, the response to the load may be in a transient state controlled by mantle viscosity. Both scenarios probably require that Mars has a subchondritic abundance of heat-producing elements.

Chromosomal alterations in oligodendroglial tumours over multiple surgeries: is tumour progression associated with change in 1p/19q status?

BACKGROUND

Oligodendroglial neoplasms have morphologic and genotypic heterogeneity. Loss of heterozygosity (LOH) of 1p and/or 19q is associated with increased treatment responsiveness and overall survival. However, the pathogenesis of treatment-resistance is unknown. We sought to determine if tumour progression is due to a proliferating sub-population of tumour cells with intact 1p, or if recurrent tumours retain 1p/19q LOH.

METHODS

24 patients with oligodendroglial neoplasms, possessing biopsy samples taken at diagnosis and at progression, were identified. 53 tumour specimens were available for LOH analysis of 1p and 19q, using PCR amplification of multiple microsatellite markers. 40 were also tested for 9p and 10q.

RESULTS

At diagnosis, the median age was 34 (24-66) years, 14 were male. 19 tumours were WHO Grade II, and 5 were high grade. The most common genomic status was 19q LOH (70%). 13 (54%) tumours were 1p LOH at diagnosis: of these, 12 were 19q LOH, and 1 was 19q uninformative. All 12 patients with 1p/19q LOH primary tumours had persistent co-deletion at progression. 9 (38%) tumours were 1p intact at diagnosis, and 8 remained 1p intact in the progressed tumours. There was little heterogeneity of 9p and 10q between tumours at diagnosis and progression.

CONCLUSION

100% of oligodendroglial tumours with 1p/19q LOH, demonstrated persistent 1p/19q LOH in the progressed tumour. Therefore, progression of these tumours is not due to a proliferating sub-population of treatment-resistant, 1p intact tumour cells. We propose that additional mutations contribute to this aggressive phenotype, however, 9p LOH or 10q LOH are unlikely to be involved.

Accumulation and Erosion of Mars' South Polar Layered Deposits

Mars' polar regions are covered with ice-rich layered deposits that potentially contain a record of climate variations. The sounding radar SHARAD on the Mars Reconnaissance Orbiter mapped detailed subsurface stratigraphy in the Promethei Lingula region of the south polar plateau, Planum Australe. Radar reflections interpreted as layers are correlated across adjacent orbits and are continuous for up to 150 kilometers along spacecraft orbital tracks. The reflectors are often separated into discrete reflector sequences, and strong echoes are seen as deep as 1 kilometer. In some cases, the sequences are dipping with respect to each other, suggesting an interdepositional period of erosion. In Australe Sulci, layers are exhumed, indicating recent erosion.

No evidence for thick deposits of ice at the lunar south pole

Shackleton crater at the Moon's south pole has been suggested as a possible site of concentrated deposits of water ice, on the basis of modelling of bi-static radar polarization properties and interpretations of earlier Earth-based radar images. This suggestion, and parallel assumptions about other topographic cold traps, is a significant element in planning for future lunar landings. Hydrogen enhancements have been identified in the polar regions, but these data do not identify the host species or its local distribution. The earlier Earth-based radar data lack the resolution and coverage for detailed studies of the relationship between radar scattering properties, cold traps in permanently shadowed areas, and local terrain features such as the walls and ejecta of small craters. Here we present new 20-m resolution, 13-cm-wavelength radar images that show no evidence for concentrated deposits of water ice in Shackleton crater or elsewhere at the south pole. The polarization properties normally associated with reflections from icy surfaces in the Solar System were found at all the observed latitudes and are strongly correlated with the rock-strewn walls and ejecta of young craters, including the inner wall of Shackleton. There is no correlation between the polarization properties and the degree of solar illumination. If the hydrogen enhancement observed by the Lunar Prospector orbiter indicates the presence of water ice, then our data are consistent with the ice being present only as disseminated grains in the lunar regolith.

Kidney transplantation into an ileal conduit: a single center experience of 59 cases

PURPOSE

Congenital and acquired conditions of the lower urinary tract can lead to renal failure requiring transplantation. Under these circumstances transplantation into a urinary diversion or an augmented bladder may be the only option. We report our experience with renal transplantation into ileal conduits in the last 22 years.

MATERIALS AND METHODS

Between January 1980 and August 2002, 59 renal transplants were drained into an ileal conduit in 54 patients at our center, accounting for 2.3% of the total number of transplants during this period. Median patient age was 28 years (range 1 to 63) and 13 patients were children. There were 12 living related and 47 cadaveric kidneys transplanted. Spina bifida, the most common cause of end stage renal disease, was seen in 22 patients (41%). Patient and graft survival following transplantation into an ileal conduit were compared with that in the 2,579 other transplants done at this center between January 1980 and December 2001.

RESULTS

Actuarial graft survival was 90% at 1 year, 63% at 5 years, 52% at 10 years and 52% at 15 years. Actuarial patient survival was 95% at 1 year, 83% at 5 years, 69% at 10 years and 69% at 15 years. Graft and patient survival was statistically similar to the outcome of the 2,579 other transplants done at our center between January 1980 and December 2001. At a mean followup of 4.6 years (range 0.1 to 20) mean serum creatinine in the 39 functioning grafts was 156 mmol/l. Of the surgical complications 21% were directly attributable to the ileal conduit and it could be considered a risk factor contributing to the complication in a further 39%. Symptomatic urinary tract infection was noted in 65% of the patients, although it did not lead to graft loss. At followup 7 patients had died with a functioning graft. Grafts were lost due to chronic allograft nephropathy in 3 cases, renal artery stenosis in 2, renal vein thrombosis in 2, and acute severe rejection, staghorn calculus and ureteroileal stricture in 1 each.

CONCLUSIONS

Kidney transplant drainage into an ileal conduit for urinary diversion is an effective treatment for patients with end stage renal disease due to abnormal lower urinary tracts. Despite preexisting co-morbidity and the increased complication rate long-term graft and patient survival is comparable to that in the normal transplant population.

Tacrolimus is not associated with gingival overgrowth in renal transplant patients

BACKGROUND

Cyclosporin A is used extensively to prevent the rejection of allogenic renal transplants. However, it is associated with a variety of undesirable side effects including gingival overgrowth. Tacrolimus (FK506), has been marketed as an effective alternative immunosuppressant to cyclosporin A and recent subjective reports suggest patients taking it complain infrequently of gingival problems. This clinical investigation was undertaken to confirm whether or not tacrolimus adversely affected the gingival health of renal transplant recipients.

METHODS

Renal transplant patients (RTPs) under the care of the Renal Transplantation Service at the Manchester Royal Infirmary, who had received a renal allograft at least 18 months earlier, were recruited for this study. All but one of the RTPs had been taking tacrolimus since transplantation. The other had commenced tacrolimus therapy two months after receiving her allograft. A hospital based control group was recruited from non transplanted individuals attending the Turner Dental School, Manchester. Each patient underwent a detailed dental assessment and had dental impressions taken. The extent of gingival overgrowth was determined from plaster models.

RESULTS

25 renal transplant recipients and 26 control patients were included in the study. None of the individuals in either the tacrolimus or control groups had clinically significant overgrowth. The patients in the tacrolimus group with the highest overgrowth scores were those also taking calcium antagonists as treatment for hypertension.

CONCLUSION

This study demonstrates that tacrolimus has no adverse effects on the gingival tissues and thus has potential as an alternative immunosuppressant for individuals susceptible to developing cyclosporin A-induced gingival overgrowth.

Three clusters of ciguatera poisoning: clinical manifestations and public health implications

Between July 1997 and August 1998 we investigated three clusters (26 cases) of ciguatera poisoning in the inner Sydney area. Tropical reef fish were implicated in each cluster. Most of those affected had musculoskeletal, neurological and gastrointestinal symptoms. The clusters raise questions about the need for rapid diagnosis and enhanced surveillance mechanisms, the regulation of fish supply, and the lack of testing facilities for ciguatera toxin.

Reduction in gingival overgrowth associated with conversion from cyclosporin A to tacrolimus

BACKGROUND

Unsightly gingival overgrowth affects many individuals immunosuppressed with cyclosporin A (CsA). Current management involves repeated periodontal surgery and intensive hygienist support. Tacrolimus is an effective alternative immunosuppressive agent for renal transplantation which does not appear to produce gingival enlargement.

AIMS

The purpose of the present study was to monitor the gingival response of 4 renal transplant patients (RTPs), with clinically significant CsA-induced gingival overgrowth, after their immunosuppressive therapy was switched to tacrolimus.

METHODS

Intra-oral photographs and alginate impressions were taken both prior to the drug conversion and again, 6 to 9 months later. Gingival overgrowth scores were determined, from plaster models on both these occasions.

RESULTS

All of the RTPs experienced significant resolution of their gingival enlargement within the time period studied; however, only one had complete regression.

CONCLUSION

It is concluded that conversion of RTPs with gingival overgrowth from CsA to tacrolimus may provide an effective management strategy for this clinical problem.

The calcium channel blocker used with cyclosporin has an effect on gingival overgrowth

BACKGROUND/AIMS

To investigate whether the choice of calcium channel blocker, used in conjunction with cyclosporin A, affected the prevalence of gingival overgrowth.

METHOD

A cohort of 135 renal transplant recipients who had been medicated with cyclosporin A in combination with either nifedipine (89) or amlodipine (46) since transplant, took part in the study. The inclusion criteria were that eligible subjects had been in receipt of a kidney transplant for at least 12 months, had at least 10 teeth and had not received specialist periodontal treatment. The age, gender, current drug regimen and dosage were recorded for each participant and alginate impressions taken of both arches. The presence and severity of gingival overgrowth were scored from plaster models.

RESULTS

A higher proportion (72%) of the amlodipine group were categorised as having gingival overgrowth compared with only 53% of the nifedipine group, chi square=4.5, p<0.05. Logistic regression analysis was used to explore the relationship between the presence or absence of gingival overgrowth (dependent variable) and age, gender, time since transplant, dose of cyclosporin A, centre in which the patient was treated, and the calcium channel blocker used (independent variables). Independent predictors of gingival overgrowth in this multivariate analysis were whether the individual was treated with amlodipine or nifedipine (p=0.01) and whether the individual was young or old (p=0.01). Within the multivariate analysis, the odds ratio for amlodipine to be associated with gingival overgrowth compared with nifedipine was 3.0 (confidence interval 1.3-6.9).

CONCLUSIONS

The prevalence of gingival overgrowth in renal transplant recipients maintained on cyclosporin A and nifedipine is lower than those treated with cyclosporin A and amlodipine.

Inhibition of the expression of conditioned cardiac responses in the developing rat

It is generally recognized that during development the capacity to express learning in terms of changes in somatomotor activity is evident earlier than the capacity for learned changes in autonomic responding (e.g., heart rate). In this series of experiments, findings indicate that changes in heart rate to a visual conditioned stimulus (CS) paired with a footshock unconditioned stimulus (US) can be observed as early in development in the rat as freezing responses. However, cardiac responses are inhibited from being expressed by preweanlings (but not adults) during CS-US pairings, the time when heart rate responses are often measured. This inhibition appears to arise from US exposure, and dissipates completely within 2 hr of training. These findings are discussed with respect to developmental changes in US-evoked autonomic arousal and response system dissociations.

Utilizing sonography to follow fetal growth

In utero diagnosis of fetal growth abnormalities continues to pose a clinical dilemma. Although significant advances have been made in the understanding of growth disturbances and their clinical importance, false-positive and false-negative diagnoses of IUGR and excessive fetal growth continue to affect the accuracy of antenatal diagnosis. Until more accurate methods are developed to aid in diagnosis, multiple biometric parameters should be assessed in patients either at risk for or with a suspected growth disturbance. Serial measurements obtained every 2 to 3 weeks may enhance diagnostic capabilities. Although antenatal diagnosis of IUGR has been shown to be of benefit in improving outcome, more study is needed to determine whether there is a benefit in antenatal diagnosis of macrosomia or LGA.

Autonomic and behavioral correlates of appetitive conditioning in rats

The cardiac responses accompanying conditioned stimulus- (CS)-generated (orienting) and unconditioned stimulus- (US)-generated appetitively motivated behaviors (P. C. Holland, 1977) were investigated. On the basis of contemporary psychophysiological research, CS-generated responses were predicted to produce bradycardia, and US-generated responses to produce tachycardia. Pairing a 10-s visual CS with food delivery produced conditioned behavioral orienting (rearing) during the initial portion of the CS, followed by magazine approach (US-generated) responses as the CS progressed. CS onset produced a decrease in heart rate, mediated by an increase in parasympathetic stimulation of the heart, which persisted throughout the 10-s CS; no support for a biphasic cardiac response was observed. These data are discussed with respect to other conditioned autonomic responses and their relevance to foraging and food ingestion.

Autonomic and behavioral correlates of appetitive conditioning in rats

The cardiac responses accompanying conditioned stimulus- (CS)-generated (orienting) and unconditioned stimulus- (US)-generated appetitively motivated behaviors (P. C. Holland, 1977) were investigated. On the basis of contemporary psychophysiological research, CS-generated responses were predicted to produce bradycardia, and US-generated responses to produce tachycardia. Pairing a 10-s visual CS with food delivery produced conditioned behavioral orienting (rearing) during the initial portion of the CS, followed by magazine approach (US-generated) responses as the CS progressed. CS onset produced a decrease in heart rate, mediated by an increase in parasympathetic stimulation of the heart, which persisted throughout the 10-s CS; no support for a biphasic cardiac response was observed. These data are discussed with respect to other conditioned autonomic responses and their relevance to foraging and food ingestion.

Emergence of conditioned cardiac responses to an olfactory CS paired with an acoustic startle UCS during development: form and autonomic origins

Pairing an olfactory conditioned stimulus (CS) with an acoustic startle unconditioned stimulus (UCS) produced conditioned bradycardia in rats ranging from 12 days of age to adulthood but failed to produce conditioning in 10-day-olds (Experiment 1). The second experiment compared the effects of two different UCSs, acoustic startle and electric shock. The startle UCS produced conditioned bradycardia accompanied by immobility. In contrast, the shock UCS produced conditioned tachycardia accompanied by behavioral activation. Pharmacological analysis revealed that activation of the parasympathetic nervous system (PNS) produced the conditioned bradycardia (Experiment 3) and that activation of the sympathetic nervous system (SNS) produced the conditioned tachycardia (Hunt, Hess, & Campbell, 1994). Further comparisons revealed that the startle UCS established conditioning several days earlier in development than the shock UCS. The ability of the PNS to respond to phasic stimulation earlier in development than the SNS was discussed as a possible mechanism for the early development of conditioned bradycardia.

Developmental and pharmacological analysis of the cardiac response to an acoustic startle stimulus

The purpose of this research was to study the cardiac response of preweanling and adult rats to 10 presentations of an acoustic startle stimulus (0 ms rise time, 100 ms, 130 dB, white noise stimulus). The first presentation of the startle stimulus produced a decrease in heart rate (HR) at both ages. With continued stimulus presentations, the response shifted to tachycardia in the adults but remained bradycardia in the preweanlings. Pharmacological analysis revealed that the startle stimulus activated only the parasympathetic system in the preweanling rats on all 10 trials. In contrast, the startle stimulus produced coactivation of the parasympathetic and sympathetic systems in the adults on the first trial, with the parasympathetic system predominating, and solely sympathetic activation on later trials. These results are discussed in terms of current psychophysiological models of (a) the cardiac response to startle stimuli and (b) autonomic space.

Megaloblastic anemia in pregnancy

Megaloblastic anemia is one of the acquired nutritional anemias that may complicate pregnancy. It is most often secondary to folic acid deficiency because folate requirements are increased during gestation. When the diagnosis of megaloblastic anemia is confirmed, appropriate therapy will initiate a rapid reversal of the anemia process. Because of the association between neural tube defects and folate deficiency, it is recommended that women of reproductive age take folic acid supplementation.

Delayed development of conditioned heart rate responses to auditory stimuli in the rat

This study examined heart rate responses to an auditory conditioned stimulus during development in the rat. The unconditioned stimulus (US) in all experiments was an acoustic startle stimulus. The conditioned stimulus elicited a monophasic bradycardia in animals 21 days of age and older, but no response in younger animals. These results are strikingly similar to an earlier study that used shock as the US (Campbell & Ampuero, 1985). Further, the conditioned cardiac response in adults was found to be mediated entirely through activation of the parasympathetic division of the autonomic nervous system (ANS) even though the US unconditionally activates the sympathetic system at that age. The delayed development of several different forms of conditioned fear is discussed.

Paradoxical autonomic responses to aversive stimuli in the developing rat

The goals of this research were to determine (a) the change in heart rate elicited by aversive auditory stimuli in the laboratory rat at different ages and (b) the autonomic origins of those changes at each age. The results of the first 2 experiments showed that aversive white noise stimuli elicited cardiac deceleration in preweanling (16-day-old) rats and cardiac acceleration in weanling (23-day-old), periadolescent (30-day-old), and adult (60-day-old) rats. Subsequent experiments showed that (a) the decrease in heart rate elicited by the noise stimulus in preweanling rats was mediated by parasympathetic activation of the heart, (b) the stimulus-elicited increase in heart rate elicited by the noise in periadolescent rats was mediated by parasympathetic withdrawal of the heart, and (c) the noise-induced increase in heart rate in adult rats was primarily mediated by sympathetic activation of the heart.

Vasovagal syncope and head upright tilt table testing

Syncope is a common medical complaint that is responsible for a significant number of emergency department visits and hospitalizations each year. A majority of syncopal events are believed to be caused by vasovagal responses. Although vasovagal syncope is essentially equivalent to simple fainting, the physiologic events that lead to this phenomena are complex. Although not completely understood, the most commonly held theory explaining vasovagal syncope involves a series of reflexive interactions between cardiac mechanoreceptors and the autonomic nervous system. Until the advent of head upright tilt table testing, diagnosis of vasovagal syncope has been an assumption, made when all other causes have been eliminated. Tilt table testing allows reproduction of the syncopal event in susceptible individuals and monitoring of the patients' physiologic responses during an episode. Direct observation and documentation of symptoms permit accurate diagnosis and yield information vital to treatment and symptom control.

Paradoxical autonomic responses to aversive stimuli in the developing rat

The goals of this research were to determine (a) the change in heart rate elicited by aversive auditory stimuli in the laboratory rat at different ages and (b) the autonomic origins of those changes at each age. The results of the first 2 experiments showed that aversive white noise stimuli elicited cardiac deceleration in preweanling (16-day-old) rats and cardiac acceleration in weanling (23-day-old), periadolescent (30-day-old), and adult (60-day-old) rats. Subsequent experiments showed that (a) the decrease in heart rate elicited by the noise stimulus in preweanling rats was mediated by parasympathetic activation of the heart, (b) the stimulus-elicited increase in heart rate elicited by the noise in periadolescent rats was mediated by parasympathetic withdrawal of the heart, and (c) the noise-induced increase in heart rate in adult rats was primarily mediated by sympathetic activation of the heart.