Effect of low dose intracoronary alteplase on global circumferential strain (myocardial strain CMR substudy from the T-TIME trial)

Background

Microvascular obstruction affects half of patients with ST-segment elevation myocardial infarction (STEMI) and confers an adverse prognosis. Feature-tracking (FT) cardiac magnetic resonance (CMR) allows myocardial strain assessment from standard cine images without the need for specialist sequences. Myocardial strain reflects both systolic and diastolic function allowing the assessment of both global and regional myocardial deformation. Strain recovery is impaired in patients with microvascular obstruction. There is growing evidence to suggest that global circumferential strain may offer incremental value beyond traditional CMR endpoints.

Purpose

We aimed to determine whether a therapeutic strategy involving low-dose intracoronary alteplase improves global circumferential strain in STEMI.

Methods

Between March 17, 2016, and December 21, 2017, 440 patients presenting at 11 hospitals in the United Kingdom within 6 hours of STEMI were randomised in a 1:1:1 dose-ranging trial design. Participants were randomly assigned to treatment with placebo (n=151), alteplase 10mg (n=144), or alteplase 20mg (n=145). The primary outcome was the amount of microvascular obstruction (%left ventricular mass) quantified by CMR at 2–7 days. Global circumferential strain was a prespecified secondary endpoint measured at 2–7 days and 3 months. Troponin T AUC was measured at 0, 2, and 24 hours post reperfusion. Patients were followed up to 1 year with all events adjudicated by an independent committee.

Results

Among the 440 patients who were randomised (mean age 60.5 years; 85% male), the primary endpoint was achieved in 396 (90%), all patients were followed up to 1 year for clinical events. The amount (mean, standard deviation) of microvascular obstruction was not different between the groups (2.3% vs. 2.6% vs. 3.5% left ventricular mass); p=0.28. Global circumferential strain was worse in patients receiving alteplase. −23.1% (placebo) vs −20.6 (10mg alteplase) vs −22.0% (20mg alteplase); mean difference for both doses combined vs placebo: 1.8% (95% CI 0.5, 3.2), p=0.009. There were no differences between groups in the other CMR endpoints including LV ejection fraction (LVEF). The area-under-the-curve for troponin T measured in 317 (72%) patients was increased in both treatment groups compared to placebo, mean difference 1.53 (95% CI: 1.16, 2.01), p=0.002. There were no differences in MACE at 1 year; placebo n=16 (10.6%), 10mg alteplase n=22 (15.3%), 20mg alteplase group n=15 (10.3%).

Conclusion

In patients presenting within 6 hours of STEMI, low-dose intracoronary alteplase compared with placebo did not reduce microvascular obstruction. There was a reduction in global circumferential strain and an increase in Troponin T AUC supporting an increase in myocardial injury early after reperfusion in patients receiving alteplase. There was no differences in MACE at one year suggesting no long-term clinical sequelae.

Funding Acknowledgement

Type of funding sources: Other. Main funding source(s): T-TIME was supported by grant 12/170/4 from the Efficacy and Mechanism Evaluation (EME) programme of the National Institute for Health Research (NIHR-EME). Boehringer-Ingelheim U.K. Ltd. provided the study drugs (alteplase 10mg, 20mg), matched placebo, and sterile water for injection. Study recruitment flowchartTable- Study endpoints

1382 Retrospective Audit to Assess Compliance to National Guidance for The Follow-Up of Acute Uncomplicated Diverticulitis and Adenoma Detection Rate at University Hospital Bristol

Aim

Diverticulitis is a common cause for acute surgical admissions. UK guidance recommends uncomplicated diverticulitis is managed with antibiotics, and follow-up outpatient lower gastrointestinal (LGI) endoscopy (flexible sigmoidoscopy or colonoscopy) arranged 6-8 weeks after discharge. This audit aimed to assess compliance to national guidance and assess adenoma detection rate.

Method

Retrospective analysis of discharge summaries coded ‘diverticulitis’ from January 2017 – April 2020 at University Hospital Bristol(UHB).

Results

426 patients presented with uncomplicated diverticulitis, mean age 60.5 years (22-92 years). 42% (179/426) of patients underwent LGI endoscopy as an inpatient or on discharge. Median time to outpatient endoscopy was 70 days (6-287 days). 23% (99/426) had LGI endoscopy within the 8-week target. Histology showed: 21% (37/179) polyp; 5% (9/179) tubular adenoma; and one patient had high grade dysplasia. The histology for the remaining 28 patients with polyps showed: hyperplasia; granulation tissue; inflammation; or samples were not sent for histology. No cases of malignancy were detected.

Conclusions

58% of patients admitted with acute uncomplicated diverticulitis did not have a follow-up LGI endoscopy and only 23% had LGI endoscopy within the 8-week target. 21% had a polyp with a 5% rate of tubular adenoma and no cases of malignancy. UHB needs to improve compliance with national guidance for the arrangement of follow-up LGI endoscopy, however the absence of detection of malignancy raises the question of whether we need to re-consider its necessity for patients with uncomplicated diverticulitis.

Age-growth relationships, temperature sensitivity and palaeoclimate-archive potential of the threatened Altiplano cactus Echinopsis atacamensis

The tall (>4 m), charismatic and threatened columnar cacti, pasacana [Echinopsis atacamensis (Vaupel) Friedrich & G.D. Rowley)], grows on the Bolivian Altiplano and provides environmental and economic value to these extremely cold, arid and high-elevation (~4000 m) ecosystems. Yet very little is known about their growth rates, ages, demography and climate sensitivity. Using radiocarbon in spine dating time series, we quantitatively estimate the growth rate (5.8 and 8.3 cm yr^-1) and age of these cacti (up to 430 years). These data and our field measurements yield a survivorship curve that suggests precipitation on the Altiplano is important for this species' recruitment. Our results also reveal a relationship between nighttime temperatures on the Altiplano and the variation in oxygen isotope values in spines (δ¹⁸O). The annual δ¹⁸O minimums from 58 years of in-series spine tissue from pasacana on the Altiplano provides at least decadal proxy records of temperature (r = 0.58; P < 0.0001), and evidence suggests that there are longer records connecting modern Altiplano temperatures to sea-surface temperatures (SSTs) in the Atlantic Ocean. While the role of Atlantic SSTs on the South American Summer Monsoon (SASM) and precipitation on the Bolivian Altiplano is well described, the impact of SSTs on Altiplano temperatures is disputed. Understanding the modern impact of SSTs on temperature on the Altiplano is important to both understand the impact of future climate change on pasacana cactus and to understand past climate changes on the Altiplano. This is the best quantitative evidence to date of one of the oldest known cactus in the world, although there are likely many older cacti on the Altiplano, or elsewhere, that have not been sampled yet. Together with growth, isotope and age data, this information should lead to better management and conservation outcomes for this threatened species and the Altiplano ecosystem.

Renal trace elements in barren-ground caribou subpopulations: Temporal trends and differing effects of sex, age and season

Caribou (Rangifer tarandus) are a culturally significant food resource for communities in northern Canada and Greenland. Many barren-ground caribou subpopulations are currently in decline, some dramatically; understanding the influence of stressors, such as toxic trace metals, is important. These contaminants enter Arctic terrestrial environments via atmospheric transport from industrialized areas and from local sources, accumulating there in the environment. Understanding how trace element concentrations interact and are influenced by caribou sex, age and season of collection is essential to evaluating trends in these elements over time and differences among subpopulations. We used path analysis to model the direct and indirect relationships between these variables in the Porcupine subpopulation and in barren-ground caribou from the Canadian Arctic and Greenland. Renal cadmium (Cd), copper (Cu) and mercury (Hg) varied significantly among subpopulations. Hg was positively correlated with Cd, Cu and selenium (Se) in female Porcupine caribou whereas Cd and Cu were negatively correlated in male Porcupine caribou. Age, season and sex influenced all three element concentrations and should be considered when comparing elements among caribou subpopulations or years. Renal Cd decreased slightly from the Canadian Western Arctic to Greenland and increased slightly over time, possibly reflecting patterns of atmospheric deposition. Renal Hg did not change significantly over time, and differences among subpopulations did not follow specific geographical patterns. Renal Cu declined over time, the changes being markedly different among subpopulations, sexes and seasons. This temporal decline is likely due to changes in diet, which could be driven by various environmental factors. Declining Cu concentrations in caribou is of concern as low levels could negatively affect reproductive success and therefore caribou at a population level. Continuing to monitor element concentrations in caribou is essential to better comprehend potential threats facing the species, and to promote food security in communities harvesting this important resource.

Establishing the Maximum Collectivity in Highly Deformed N=Z Nuclei

The lifetimes of the first excited 2^{+} states in the N=Z nuclei ^{80}Zr, ^{78}Y, and ^{76}Sr have been measured using the γ-ray line shape method following population via nucleon-knockout reactions from intermediate-energy rare-isotope beams. The extracted reduced electromagnetic transition strengths yield new information on where the collectivity is maximized and provide evidence for a significant, and as yet unexplained, odd-odd vs even-even staggering in the observed values. The experimental results are analyzed in the context of state-of-the-art nuclear density-functional model calculations.

Cerebrospinal fluid HIV RNA in persons living with HIV

OBJECTIVES

Despite adequate suppression of plasma HIV RNA, viral escape in cerebrospinal fluid (CSF) is widely reported. Rates of CSF HIV RNA escape vary in the literature. In persons living with HIV (PLWH) undergoing lumbar puncture examination for clinical reasons, we assessed rates of CSF HIV RNA escape.

METHODS

Persons living with HIV attending a designated HIV neurology service undergoing CSF assessment for clinical reasons between January 2015 and April 2017 were included in the study. CSF HIV RNA escape was defined as HIV RNA ≥ 0.5 log₁₀ HIV-1 RNA copies/mL higher than plasma HIV RNA or detectable CSF HIV RNA when plasma HIV RNA was < 20 copies/mL. Clinical factors associated with CSF HIV RNA were assessed using logistic regression modelling.

RESULTS

Of 38 individuals, 35 were receiving antiretroviral therapy, 30 were male and their mean age was 51 years. Clinical reasons for CSF assessment included investigation for cognitive decline (n = 25), early syphilis (n = 4) and other central nervous system (CNS) conditions (n = 9). HIV RNA was detectable in plasma and CSF in seven and six individuals, respectively, with two individuals (5.3%) meeting the definition of CSF escape. Detectable CSF HIV RNA was associated with a detectable plasma HIV RNA (P < 0.001) and a history of known antiretroviral drug resistance mutations (P = 0.021).

CONCLUSIONS

The prevalence of CSF viral escape in PLWH undergoing lumbar puncture examination for clinical reasons is lower than previously reported.

Using cognitive pre-testing methods in the development of a new evidenced-based pressure ulcer risk assessment instrument

Background

Variation in development methods of Pressure Ulcer Risk Assessment Instruments has led to inconsistent inclusion of risk factors and concerns about content validity. A new evidenced-based Risk Assessment Instrument, the Pressure Ulcer Risk Primary Or Secondary Evaluation Tool - PURPOSE-T was developed as part of a National Institute for Health Research (NIHR) funded Pressure Ulcer Research Programme (PURPOSE: RP-PG-0407-10056). This paper reports the pre-test phase to assess and improve PURPOSE-T acceptability, usability and confirm content validity.

Methods

A descriptive study incorporating cognitive pre-testing methods and integration of service user views was undertaken over 3 cycles comprising PURPOSE-T training, a focus group and one-to-one think-aloud interviews. Clinical nurses from 2 acute and 2 community NHS Trusts, were grouped according to job role. Focus group participants used 3 vignettes to complete PURPOSE-T assessments and then participated in the focus group. Think-aloud participants were interviewed during their completion of PURPOSE-T.

After each pre-test cycle analysis was undertaken and adjustment/improvements made to PURPOSE-T in an iterative process. This incorporated the use of descriptive statistics for data completeness and decision rule compliance and directed content analysis for interview and focus group data. Data were collected April 2012-June 2012.

Results

Thirty-four nurses participated in 3 pre-test cycles. Data from 3 focus groups, 12 think-aloud interviews incorporating 101 PURPOSE-T assessments led to changes to improve instrument content and design, flow and format, decision support and item-specific wording. Acceptability and usability were demonstrated by improved data completion and appropriate risk pathway allocation. The pre-test also confirmed content validity with clinical nurses.

Conclusions

The pre-test was an important step in the development of the preliminary PURPOSE-T and the methods used may have wider instrument development application. PURPOSE-T proposes a new approach to pressure ulcer risk assessment, incorporating a screening stage, the inclusion of skin status to distinguish between those who require primary prevention and those who require secondary prevention/treatment and the use of colour to support pathway allocation and decision making. Further clinical evaluation is planned to assess the reliability and validity of PURPOSE-T and it’s impact on care processes and patient outcomes.

The outcome of the Mobility total ankle replacement at a mean of four years

We performed a retrospective review of a consecutive series of 178 Mobility total ankle replacements (TARs) performed by three surgeons between January 2004 and June 2009, and analysed radiological parameters and clinical outcomes in a subgroup of 129 patients. The mean follow-up was 4 years (2 to 6.3). A total of ten revision procedures (5.6%) were undertaken. The mean Ankle Osteoarthritis Scale (AOS) pain score was 17 (0 to 88) and 86% of patients were clinically improved at follow-up. However, 18 patients (18 TARs, 14%) had a poor outcome with an AOS pain score of > 30. A worse outcome was associated with a pre-operative diagnosis of post-traumatic degenerative arthritis. However, no pre- or post-operative radiological parameters were significantly associated with a poor outcome. Of the patients with persistent pain, eight had predominantly medial-sided pain. Thirty TARs (29%) had a radiolucency in at least one zone.

The outcome of the Mobility TAR at a mean of four years is satisfactory in > 85% of patients. However, there is a significant incidence of persistent pain, particularly on the medial side, for which we were unable to establish a cause.

Cite this article: Bone Joint J 2013;95-B:1366–71.

The outcome of the Mobility total ankle replacement at a mean of four years: Can poor outcomes be predicted from pre- and post-operative analysis?

We performed a retrospective review of a consecutive series of 178 Mobility total ankle replacements (TARs) performed by three surgeons between January 2004 and June 2009, and analysed radiological parameters and clinical outcomes in a subgroup of 129 patients. The mean follow-up was 4 years (2 to 6.3). A total of ten revision procedures (5.6%) were undertaken. The mean Ankle Osteoarthritis Scale (AOS) pain score was 17 (0 to 88) and 86% of patients were clinically improved at follow-up. However, 18 patients (18 TARs, 14%) had a poor outcome with an AOS pain score of > 30. A worse outcome was associated with a pre-operative diagnosis of post-traumatic degenerative arthritis. However, no pre- or post-operative radiological parameters were significantly associated with a poor outcome. Of the patients with persistent pain, eight had predominantly medial-sided pain. Thirty TARs (29%) had a radiolucency in at least one zone. The outcome of the Mobility TAR at a mean of four years is satisfactory in > 85% of patients. However, there is a significant incidence of persistent pain, particularly on the medial side, for which we were unable to establish a cause.

PAH fluxes to Siskiwit revisted: trends in fluxes and sources of pyrogenic PAH and perylene constrained via radiocarbon analysis

Trends in concentrations and radiocarbon content of pyrogenic PAHs and perylene were determined 20 years after a previous study by Mcveety and Hites (1988). Pyrogenic PAH fluxes to sediments were observed to continue to decrease over the period from 1980 to 2000 at this remote site in contrast to observations in more urban areas. Radiocarbon analysis of pyrogenic PAHs showed a 50% decrease in the proportion of pyrogenic PAH derived from fossil fuel combustion over the past 50 years, consistent with decreasing emissions from regional coal-fired power-generating plants. Fluxes of pyrogenic PAHs related to biomass burning were consistent over this same period and found to exceed fossil fuel sources in the most recent samples. Fluxes of biomass-derived pyrogenic PAHs were similar in magnitude to total pyrogenic PAH fluxes in early 1900, suggesting that these fluxes may represent wildfire inputs. Not only did perylene concentrations in these sediments increase with depth as previously observed but also concentrations from the same sedimentary layers analyzed 20 years previously showed large increases in perylene concentrations. Radiocarbon analysis of perylene indicated that 70-85% of perylene observed in the deeper sediments could be explained by production from total organic carbon.

How well do environmental archives of atmospheric mercury deposition in the Arctic reproduce rates and trends depicted by atmospheric models and measurements?

This review compares the reconstruction of atmospheric Hg deposition rates and historical trends over recent decades in the Arctic, inferred from Hg profiles in natural archives such as lake and marine sediments, peat bogs and glacial firn (permanent snowpack), against those predicted by three state-of-the-art atmospheric models based on global Hg emission inventories from 1990 onwards. Model veracity was first tested against atmospheric Hg measurements. Most of the natural archive and atmospheric data came from the Canadian-Greenland sectors of the Arctic, whereas spatial coverage was poor in other regions. In general, for the Canadian-Greenland Arctic, models provided good agreement with atmospheric gaseous elemental Hg (GEM) concentrations and trends measured instrumentally. However, there are few instrumented deposition data with which to test the model estimates of Hg deposition, and these data suggest models over-estimated deposition fluxes under Arctic conditions. Reconstructed GEM data from glacial firn on Greenland Summit showed the best agreement with the known decline in global Hg emissions after about 1980, and were corroborated by archived aerosol filter data from Resolute, Nunavut. The relatively stable or slowly declining firn and model GEM trends after 1990 were also corroborated by real-time instrument measurements at Alert, Nunavut, after 1995. However, Hg fluxes and trends in northern Canadian lake sediments and a southern Greenland peat bog did not exhibit good agreement with model predictions of atmospheric deposition since 1990, the Greenland firn GEM record, direct GEM measurements, or trends in global emissions since 1980. Various explanations are proposed to account for these discrepancies between atmosphere and archives, including problems with the accuracy of archive chronologies, climate-driven changes in Hg transfer rates from air to catchments, waters and subsequently into sediments, and post-depositional diagenesis in peat bogs. However, no general consensus in the scientific community has been achieved.

Polybrominated diphenyl ethers and their methoxylated and hydroxylated analogs in Brown Bullhead (Ameiurus nebulosus) plasma from Lake Ontario

Polybrominated diphenyl ethers (PBDEs), methoxylated PBDEs (MeO-PBDEs) and hydroxylated PBDEs (OH-PBDEs) were detected and quantified in Brown Bullhead (Ameiurus nebulosus) from Lake Ontario. Samples were collected in 2006 from three different locations near the city of Toronto: Frenchman's Bay, Toronto Island, and Tommy Thompson Park. A total of 117 plasma samples were pooled into 19 samples, separating males and females by site of capture. Pooled samples were analyzed for 36 PBDEs, 20 MeO-PBDEs and 20 OH-PBDEs, but only six PBDEs, five MeO- and eight OH-compounds were confirmed against standards currently available. These peaks were quantified as "identified" peaks, while peaks matching ion ratios but not matching the retention time of the available standards were quantified as "unidentified" peaks. Both "identified" and "unidentified" concentrations were combined to obtain a total concentration. No significant variations were obtained for total PBDE concentrations, ranging from 3.33 to 9.02 ng g(-1)wet weight. However, OH- and MeO-PBDE totals ranged over 1 order of magnitude among the samples (not detected - 3.57 ng g(-1)wet weight for OH-PBDEs and not detected -0.10 ng/g wet weight for MeO-PBDE). The results of this study suggested that these compounds are ubiquitous in biota. Source estimation of MeO- and OH-PBDEs in freshwater fish were discussed. Considering that up to date no freshwater sources for MeO- or OH-PBDEs have been reported, concentrations found should be mainly related to bioaccumulation from anthropogenic sources, although other sources could not be dismissed.

Rapid HIV testing using Determine™ HIV 1/2 antibody tests: is there a difference between the visual appearance of true- and false-positive tests?

HIV point-of-care tests (POCTs) give occasional false positive results, causing unnecessary patient anxiety. We aimed to elicit whether false- and true-positive POCTs differed visually. Seventeen false- and 17 true-positive serum samples were randomized into pairs, comprising one false- and one true-positive sample. Two independent readers identified each POCT as negative or positive and compared line strength between pairs. Six further readers graded line strength, 0-5, from POCT photographs. All true-positive samples were identified positive and 8/17 false-positive samples negative, on repeat testing of stored sera. Eight out of the 9 remaining false-positive tests were described as having weaker pigment uptake than their paired true-positive POCT. Mean grade of line strength was 4.2 in true- and 0.9 in false-positive samples, on photographic evaluation. These results suggest false-positive POCTs may differ visually from true-positive POCTs. If larger studies confirm these findings, we may be able to alleviate anxiety in low risk patients with faintly positive POCTs awaiting their confirmatory laboratory result, where the possibility of a false-positive result could be emphasized.

Nf1 haploinsufficiency augments angiogenesis

Mutations in the NF1 tumor-suppressor gene underlie neurofibromatosis type 1 (NF1), in which patients are predisposed to certain tumors such as neurofibromas and may associate with vascular disorder. Plexiform neurofibromas are slow growing benign tumors that are highly vascular and can progress to malignancy. The development of neurofibromas requires loss of both Nf1 alleles in Schwann cells destined to become neoplastic and may be exacerbated by Nf1 heterozygosity in other non-neoplastic cells. This study tested the hypothesis that Nf1 heterozygosity exaggerates angiogenesis. We found that Nf1 heterozygous mice showed increased neovascularization in both the retina and cornea in response to hypoxia and bFGF, respectively, compared to their wild-type littermates. The increase in corneal neovascularization was associated with heightened endothelial cell proliferation and migration, and increased infiltration of inflammatory cells. In addition, Nf1 heterozygous endothelial cell cultures showed an exaggerated proliferative response to angiogenic factors, particularly to bFGF. These findings support the conclusion that Nf1 heterozygosity in endothelial cells and perhaps inflammatory cells augments angiogenesis, which may promote neurofibroma formation in NF1.

Elevated mercury concentrations in fish in lakes in the Mackenzie River Basin: the role of physical, chemical, and biological factors

During the mid-1990s and through the early 2000s, researchers determined that elevated mercury concentrations were a common occurrence in predatory fish in many lakes in the Mackenzie River Basin (MRB), located in northern Canada. Here we present the results of studies investigating factors contributing to higher mercury concentrations in fish in many of these lakes. Twenty-two percent of lake trout, 33% of northern pike, and 50% of walleye populations had mean mercury concentrations >0.5 microg/g, the guideline for the commercial sale of fish. Higher mercury concentrations were strongly associated with the relatively old age of MRB predatory fish; mean age ranged from 7.6 to 24.9 years for the three species. In contrast, none of the lake trout sampled in eight lakes further south in northern Saskatchewan and Alberta had mean mercury concentrations >0.5 microg/g; fish also were younger (mean age 6 years for the 8 lakes). Mercury concentrations in MRB fish generally increased with fish length, age, and trophic feeding although the nature of these relationships varied with the lake. Mean length was a good predictor of mean mercury concentrations in walleye populations across the study lakes but not for whitefish, lake trout, and pike; age was a good predictor for lake trout and walleye. Mercury concentrations in water and invertebrates were similar to those observed in more southerly regions where fish do not have elevated mercury concentrations. Mercury concentrations tended to be higher in fish in smaller vs. larger lakes and as a probable consequence of higher summer epilimnion temperatures, which favour a higher net methylation rate, and higher mercury and methyl mercury concentrations in water which enter these lakes from the watershed. Increasing fishing pressures on MRB lakes may be a means of reducing mean fish age, improving growth rates, and decreasing mercury body burdens. Increased global warming may result in higher mercury concentrations in fish through increased water temperatures, a longer ice free season, and increased release of stored mercury from the watershed into these lakes.

Levels and spatial and temporal trends of contaminants in Greenland biota: an updated review

Knowledge of contaminant levels in Greenland biota has increased substantially in recent years, particularly for persistent organic pollutants. This paper reviews and updates knowledge of spatial and temporal trends of Cd, Hg and organochlorines (PCBs, DDTs, HCHs, HCB and chlordane-related compounds) in Greenland terrestrial, freshwater and marine biota. The most comprehensive studies of spatial trends of Cd and Hg in the terrestrial ecosystem concern lichens, with relatively complete coverage, and caribou (Rangifer tarandus), with coverage mainly in different regions of central West Greenland and Southwest Greenland. The Arctic char (Salvelinus alpinus) is the only freshwater organism for which studies of spatial trends of Hg levels have been completed. Information on spatial trends of Cd and Hg in the marine environment is available from studies of fish, seabirds, ringed seals (Phoca hispida) and polar bears (Ursus maritimus). Geographical patterns of Cd and Hg in Greenland biota were not always consistent among different species or different studies. In landlocked Arctic char the concentrations of Hg decreased from south to north. In marine animals levels of Hg tended to be higher in East Greenland than in West Greenland and Cd levels were highest in biota from Disko Island in central West Greenland. The observed regional differences are difficult to explain but in most cases the causes appear to be natural rather than anthropogenic. Only a few time series covering the last 20 years exist for Cd and Hg. The one time series indicating a temporal change is for ringed seals in Northwest Greenland, which shows an increasing trend of Hg and a decreasing trend of Cd since 1984. Whether the changes reflect anthropogenic inputs, seal behaviour or other environmental factors is unknown. The most significant new insights have concerned organochlorines. In general, levels of these compounds were very low in terrestrial biota compared to marine species. Concentrations in landlocked Arctic char were highest in Southeast Greenland and lowest in Northwest and Northeast Greenland. Marine species from East Greenland had consistently higher levels of SigmaPCB, SigmaDDT and SigmaHCH than marine species from West Greenland. Very few data exist to evaluate temporal changes of organochlorine levels in Greenland biota, and this is the most significant knowledge gap at present. The most pronounced change observed was a decrease of 78% in SigmaPCB levels in polar bears from East Greenland from 1990 to 2000. Levels of SigmaHCH in shorthorn sculpins (Myoxocephalus scorpius) and seals from both central West Greenland and central East Greenland appear to have decreased since 1994. Increasing trends of SigmaDDT from 1994 until now were found in both sexes of seals as well as in male sculpins from central West Greenland.

Specialist vaccination advice and pockets of resistance to MMR vaccination: lessons from an outbreak of measles

An outbreak of measles was associated with a private nursery school in north west London. Sixteen cases were identified of whom 13 were laboratory confirmed. The majority of cases were aged three years or younger. Older cases were siblings of younger cases. None of the cases had been vaccinated against measles. In the nursery school 33% of the children had not received MMR vaccination. Based on specialist advice from the Health Protection Agency the outbreak control team recommended that children with no history of MMR vaccination should have a first MMR dose as soon as possible and that children with one MMR dose should receive the second dose as soon as possible (minimum of one month between doses). Some parents had strong negative views about MMR and represented 'pockets of resistance' to vaccination advice. The specialist vaccination advice, which was different to national immunisation guidelines, also caused some confusion amongst other health professionals. With a decrease in MMR vaccination uptake and resulting increased potential for future measles outbreaks, clinicians should be aware of and understand specialist vaccination advice intended to deal with outbreaks.

Male versus female breast cancers. A population-based comparative immunohistochemical analysis

CONTEXT

The rate of male breast cancer is a small fraction of that observed in females, thus severely limiting our understanding of the pathogenesis of this condition. It remains unclear whether the biological behavior and tumor progression associated with male breast cancer parallel that of the female form.

OBJECTIVES

To evaluate the immunohistochemical profile of male breast carcinomas and to compare this profile with that of stage-matched female breast cancers.

DESIGN

Seventy-five cases of primary male breast cancer were identified using the records of the Saskatchewan Cancer Foundation over a period of 26 years (1970-1996). Fifty-nine of these cases had formalin-fixed, paraffin-embedded tissue blocks available for the purposes of this study. All cases were reviewed and a standardized modified Bloom-Richardson grading criterion was applied. Estrogen receptor status, progesterone receptor status, c-Erb-B2 expression, p53 expression, and Bcl-2 expression were evaluated by immunohistochemistry. Results from 240 consecutive cases of stage-matched female breast cancers analyzed in the same laboratory were used as a standard set for comparison.

RESULTS

Male breast cancers tended to be high grade (85% grade 3) in comparison with the female breast cancers (50% grade 3). In descriptive analysis across all stages of disease, male carcinomas were more frequently estrogen receptor positive (81% vs 69%) than their female counterparts. Despite their high grade, they were less likely to overexpress p53 (9% vs 28%) and Erb-B2 (5% vs 17%) than the female counterparts. There was no significant difference in either progesterone receptor (63% vs 56%) or Bcl-2 (79% vs 76%) overexpression. Stratified analysis by stage-matched controls showed no statistically significant differences among the men and women with stage I disease. However, in stage II-matched samples, statistically significant differences were observed between the 2 groups. The male cancers were more likely to overexpress estrogen receptor (81.6% vs 64.4%, P = .04), progesterone receptor (71.1% vs 47.5%, P = .01), and Bcl-2 (78.9% vs 69.4%, P = .20). They also showed statistically significant lower expression of p53 (7.9% vs 36.3%, P = .001) and Erb-B2 (5.3% vs 23.8% P = .01).

CONCLUSION

Male breast cancers display distinct immunophenotypic differences from those occurring in women, implying a different pathogenesis in the evolution and progression of this disease. Such differences may play key roles in therapeutic management, warranting different treatment strategies in comparison to female breast cancers.

Global distribution of halogenated dimethyl bipyrroles in marine mammal blubber

Four halogenated dimethyl bipyrroles (HDBPs), hypothesized to be naturally produced, were quantitated in marine mammal blubber from a number of species obtained from various locations worldwide. HDBPs were found in samples from all locations studied. Concentrations of total HDBPs (SigmaHDBPs) ranged from 0.4 ng/g lipid weight in ringed seals (Phoca hispida) from the White Sea to 2,540 ng/g lipid weight in Dall's porpoise (Phocoenoides dalli) from the northwestern North Pacific Ocean. At their highest levels, SigmaHDBPs made up 11% of the total quantitated organohalogen body burden of adult male Dall's porpoises. In two beluga (Delphinapterus leucas) data subsets, it was found that males contained significantly higher concentrations of SigmaHDBPs than females. No significant effects of age or sex on SigmaHDBPs were observed in harbor seal (Phoca vitulina) and bowhead whale (Balaena mysticetus) data subsets. The geographical distribution of concentrations did not resemble that of the ubiquitous anthropogenic organohalogen, polychlorinated biphenyl congener CB-153. Higher concentrations of HDBPs and different patterns of congeners were observed in samples from Pacific as opposed to non-Pacific Ocean influenced environments. Concentrations of HDBPs in beluga from the Arctic and St. Lawrence River were similar. Their high abundance in north Pacific Ocean biota and widespread occurrence suggest that HDBPs undergo extensive transport from a source located primarily in the Pacific Ocean. Evidence from HDBP congener patterns indicates that both ocean currents and atmospheric transport likely play a role in the movement of HDBPs. These results imply that HDBPs and anthropogenic organohalogens have different sources and support the natural production hypothesis.

Axonal regeneration into acellular nerve grafts is enhanced by degradation of chondroitin sulfate proteoglycan

Although the peripheral nerve has the potential to regenerate after injury, degenerative processes may be essential to promote axonal growth into the denervated nerve. One hypothesis is that the nerve contains growth inhibitors that must be neutralized after injury for optimal regeneration. In the present study, we tested whether degradation of chondroitin sulfate proteoglycan, a known inhibitor of axon growth, enhances the growth-promoting properties of grafts prepared from normal donor nerves. Excised segments of rat sciatic nerve were made acellular by freeze-killing before treatment with chondroitinase ABC. Chondroitinase-dependent neoepitope immunolabeling showed that chondroitin sulfate proteoglycan was thoroughly degraded throughout the treated nerve segments. In addition, neuronal cryoculture assays revealed that the neurite-promoting activity of acellular nerves was significantly increased by chondroitinase treatment. Control and chondroitinase-treated acellular nerves were then used as interpositional grafts in a rat nerve injury model. Axonal regeneration into the grafts was assessed 4 and 8 d after implantation by growth-associated protein-43 immunolabeling. At both time points, the number of axons regenerating into acellular grafts treated with chondroitinase was severalfold greater than in control grafts. Growth into the chondroitinase-treated grafts was pronounced after only 4 d, suggesting that the delay of axonal growth normally associated with acellular grafts was attenuated as well. These findings indicate that chondroitinase treatment significantly enhanced the growth-promoting properties of freeze-killed donor nerve grafts. Combined with the low immunogenicity of acellular grafts, the ability to improve axonal penetration into interpositional grafts by preoperative treatment with chondroitinase may be a significant advancement for clinical nerve allografting.

Tumorigenic properties of neurofibromin-deficient neurofibroma Schwann cells

Dermal and plexiform neurofibromas are peripheral nerve sheath tumors that arise frequently in neurofibromatosis type 1. The goal of the present study was to examine the tumorigenic properties of neurofibromin-deficient human Schwann cells (SCs) that were found to represent a subset of SCs present in approximately half of the total neurofibromas examined. Highly enriched SC cultures were established from 10 dermal and eight plexiform neurofibromas by selective subculture using glial growth factor-2 and laminin. These cultures had low tumorigenic potential in classical in vitro assays yet several unique preneoplastic properties were frequently observed, including delayed senescence, a lack of density-limited growth, and a strong propensity to spontaneously form proliferative cell aggregates rich in extracellular matrix. Western blot analysis failed to detect full-length neurofibromin in any of the neurofibroma SC cultures, indicating that neurofibromin-deficient SCs had a substantial growth advantage. Immunohistochemical staining of the originating tumors showed the majority were comprised principally of neurofibromin-negative SCs, whereas the remainder contained both neurofibromin-negative and neurofibromin-positive SCs. Lastly, engraftment of neurofibromin-deficient SC cultures into the peripheral nerves of scid mice consistently produced persistent neurofibroma-like tumors with diffuse and often extensive intraneural growth. These findings indicate that neurofibromin-deficient SCs are involved in neurofibroma formation and, by selective subculture, provide a resource for the development of an in vivo model to further examine the role of these mutant SCs in neurofibroma histogenesis.

Mitochondrial DNA analysis of Sporothrix schenckii in South Africa and Australia

Clinical isolates of Sporothrix schenckii were investigated for mitochondrial DNA (mtDNA) types using restriction fragment length polymorphism patterns with HaeIII. The 62isolates in South Africa comprised Types 3 (9.7%), 4 (1.6%), 11 (9.7%), 17 (77.4%) and 23 (1.6%) while the 23 Australian isolates comprised Types 3 (26.0%), 4 (56.5%), 7 (8.6%) and 21 (8.6%). In a phylogenetic tree based on the sequence divergence of mtDNA, the mtDNA types were clustered into two groups, A and B. The results suggested that isolates in South Africa mainly belong to Group A and isolates in Australia mainly belong to Group B.

Chromosome 17 loss-of-heterozygosity studies in benign and malignant tumors in neurofibromatosis type 1

Neurofibromatosis type 1 (NF1) is a common autosomal dominant condition characterized by benign tumor (neurofibroma) growth and increased risk of malignancy. Dermal neurofibromas, arising from superficial nerves, are primarily of cosmetic significance, whereas plexiform neurofibromas, typically larger and associated with deeply placed nerves, extend into contiguous tissues and may cause serious functional impairment. Malignant peripheral nerve sheath tumors (MPNSTs) seem to arise from plexiform neurofibromas. The NF1 gene, on chromosome segment 17q11.2, encodes a protein that has tumor suppressor function. Loss of heterozygosity (LOH) for NF1 has been reported in some neurofibromas and NF1 malignancies, but plexiform tumors have been poorly represented. Also, the studies did not always employ the same markers, preventing simple comparison of the frequency and extent of LOH among different tumor types. Our chromosome 17 LOH analysis in a cohort of three tumor types was positive for NF1 allele loss in 2/15 (13%) dermal neurofibromas, 4/10 (40%) plexiform neurofibromas, and 3/5 (60%) MPNSTs. Although the region of loss varied, the p arm (including TP53) was lost only in malignant tumors. The losses in the plexiform tumors all included sequences distal to NF1. No subtle TP53 mutations were found in any tumors. This study also reports the identification of both NF1 "hits" in plexiform tumors, further supporting the tumor suppressor role of the NF1 gene in this tumor type.

Predictive value of the ultrasensitive HIV viral load assay in clinical practice

The aim of this study was to determine whether an HIV viral load of <50 copies/ml (c/ml), in the first available plasma sample to have shown a viral load of <400 c/ml, in patients on antiretroviral therapy, is correlated with longer term suppression of viral load (at <400 c/ml) compared to a viral load of 50-399 c/ml, and secondly, to compare the results obtained by ultrasensitive and standard viral load assays carried out on the same sample. A total of 98 HIV-positive patients on antiretroviral therapy with a viral load of <400 c/ml and at least one subsequent viral load measurement, were selected. For each patient, the first available specimen showing a viral load of <400 c/ml was tested using the Roche Amplicor ultrasensitive viral load assay, and patients were followed up subsequently for a median period of 52 weeks. Whether patients achieved an ultrasensitive viral load (USVL) of <50 c/ml or not made very little difference to the proportion of patients in each group showing continued response to treatment (52% vs. 45% respectively). The only variable that was shown to significantly predict longevity of response was the number of antiretroviral drugs used. Secondly, a standard viral load of <400 c/ml but with a detectable signal above background levels, was strongly predictive of a USVL of >50 c/ml. Overall, the findings suggest that the advantage in predictive value of the ultrasensitive over the standard HIV viral load assay, shown previously in clinical trials, may be limited in clinical practice.

An outbreak of pulmonary mycosis in respiratory burst-deficient (gp91(phox-/-))Mice with concurrent acidophilic macrophage pneumonia

An outbreak of pulmonary abscessation due to the common environmental fungus Paecilomyces variotii occurred in a colony of gp91(phox-/-)mice, which lack functional NADPH oxidase, the enzyme complex responsible for generating the respiratory burst in phagocytes. Parenchyma surrounding the abscesses showed intense acidophilic macrophage pneumonia, and similar but much milder lesions were present in each of 24 gp91(phox-/-)mice free from other pulmonary lesions. These findings indicate a high prevalence of acidophilic macrophage pneumonia in gp91(phox-/-)mice, or at least in this particular stock. The presence of this lesion may complicate studies in which phagocyte-dependent pulmonary defence plays a significant role.

MMP-2 and MMP-9 increase the neurite-promoting potential of schwann cell basal laminae and are upregulated in degenerated nerve

Compared to degenerated nerves, the ability of normal adult peripheral nerve to support axonal regeneration is poor and may be attributed to the inhibition of endoneurial laminin by chondroitin sulfate proteoglycan (CSPG). In cryoculture assays, neuritic growth of neonatal and adult peripheral neurons was increased on sections of normal nerve by pretreatment with CSPG-degrading enzymes, including the matrix metalloproteinases MMP-2 and MMP-9. Axonal regeneration is known to occur within the Schwann cell basal laminae of degenerated nerve. Similarly, deconvolution microscopy revealed that neuritic growth on nerve tissue sections occurred principally on the lumenal surface of enzymatically modified basal laminae. Compared to normal nerve, there was a marked increase in the neurite-promoting activity of the degenerated nerve, and this activity was not increased significantly by subsequent MMP treatment. Additionally, the expression and activation of MMP-2 and MMP-9 were elevated in degenerated nerve, suggesting that degradation of inhibitory CSPG by the MMPs contributes to the growth-promoting properties of degenerated nerve.

Culture of cytogenetically abnormal schwann cells from benign and malignant NF1 tumors

Dermal and plexiform neurofibromas are benign peripheral nerve sheath tumors that arise in neurofibromatosis type 1 (NF1). NF1 patients also have an increased risk of malignant peripheral nerve sheath tumors (MPNSTs), thought to arise in a subset of plexiform neurofibromas. Plexiform neurofibroma pathogenesis is poorly understood, despite the serious clinical problem posed by these tumors. The Schwann cell is hypothesized to be the cell type initially mutated and clonally expanded in plexiform neurofibromas. To test this hypothesis and search for genetic alterations involved in tumorigenesis, we established Schwann cell cultures from plexiform and dermal neurofibromas. Cytogenetic abnormalities were identified in 4/6 plexiform cultures (including one from a plexiform with a sarcomatous component) and 0/7 dermal neurofibroma Schwann cell cultures. There were no consistent chromosomal regions involved in the abnormal karyotypes, suggesting that plexiform tumors are heterogeneous and may bear a variety of primary and/or secondary genetic changes. This is the first study to show successful culturing of genetically abnormal Schwann cell lineages from plexiform neurofibromas. Thus, we present the strongest evidence yet to support the theory that the Schwann cell is the central component in the development of plexiform neurofibromas. This is a key finding for NF1 research, which will lead to further studies of the genetic and biochemical pathogenesis of these Schwann cell tumors. Genes Chromosomes Cancer 27:117-123, 2000.

Combined alpha interferon and ribavirin for the treatment of hepatitis C in patients with hereditary bleeding disorders

Patients with hereditary bleeding disorders who received non-virally inactivated plasma-derived clotting factor concentrates before the mid-1980s invariably became infected with hepatitis C virus (HCV). Therapy with interferon alpha (IFN-alpha) alone has been disappointing in this group. We conducted an open-label study, using a combination of IFN-alpha2b (3 million units three times per week) and ribavirin 1-1.2 g/d in 28 patients with hereditary bleeding disorders. Twenty-one of the 28 patients had liver biopsy-confirmed chronic hepatitis (median histological activity index 5; range 1-10) and all patients were HCV RNA positive by PCR. Virological response rate to therapy at 3 months was 82% (23 out of 28). Three HIV co-infected patients showed an early virological response with loss of HCV RNA, but two subsequently relapsed after 3 and 6 months of therapy. Four patients stopped treatment early (one at 4, one at 7 and two at 9 months) because of treatment-related side effects, although three of these have maintained a virological response. Seventeen patients completed the 48-week course. Twenty of the 28 (71%) treated have had a durable virological response with a median follow-up of 16 months (range 1-24). Combination therapy represents a significant advance in the treatment of hepatitis C in patients with hereditary bleeding disorders.

Bcl-2 immunoreactive cells with immature neuronal phenotype exist in the nonepileptic adult human brain

Bcl-2, a cell death suppressor protein, is expressed during brain development but is largely down-regulated in the adult central nervous system. We previously reported strong expression of bcl-2 in small, "oligodendrocyte-like" cells (OLC) found in glioneuronal hamartias. These hamartias are microscopic cell rests found in temporal lobe resections from patients with intractable epilepsy and are considered a form of cerebral microdysgenesis. However, a causative relationship between these rests and seizures is not clear. We now report the identification, lineage characterization, and postnatal ontogeny of hamartia-like cell rests in temporal lobes of nonepileptic humans. Postmortem temporal lobes from 28 patients without history of neurologic disease (mean age = 53 years; range = 20 to 83 years) were studied. Microscopic cellular aggregates containing immature-appearing, bcl-2-immunoreactive cells (BIC) (identical to OLC) were observed in 23 of 28 (82%) temporal lobes from nonepileptic individuals. BIC were strongly immunoreactive for neuronal-specific class III beta tubulin, neuronal nuclear antigen, and MAP-2, but were consistently negative for neurofilament proteins and Ki67. Such cells were localized to subventricular regions of the caudal amygdala and often extended into the adjacent subcortical white matter and periamygdaloid cortex. BIC became less abundant with advancing age. These findings suggest that hamartia-like rests containing immature postmitotic neurons are normally present in the human brain and that glioneuronal hamartias may not always represent a maldevelopmental lesion associated with epilepsy.

The growth of Listeria monocytogenes in cheese packed under a modified atmosphere

The effect of modified atmosphere Packaging (MAP) on the growth of Listeria monocytogenes in mould ripened cheeses was studied at refrigeration temperatures (2-8.3 degrees C) over a storage period of 6 weeks. Control experiments in cling film with no atmospheric modification produced a lag time before growth of up to 1 week and rapid subsequent growth. MAP with a CO2 concentration of less than 20% allowed growth to occur but when O2 was incorporated; the lag time was reduced from 3 to 2 weeks and subsequent growth was also faster, producing an increase in cell numbers of 1.4 log cycles over the incubation period. N2-MAP in the absence of O2 increased the lag time to 3 weeks and slowed growth, while the inclusion of CO2 extended the lag to 3 weeks and slowed subsequent growth even more. In MAP with 80:10:10 (v/v/v) N2:CO2:O2, there was a lag period of 2-3 weeks before growth of L. monocytogenes occurred, while the total viable aerobic count (TVAC) decreased by 2-3 log cycles and the total Lactobacillus count showed little change. It was concluded that MAP was not suitable for preventing the growth of L. monocytogenes in such cheeses.

Spatial and temporal trends of contaminants in Canadian Arctic freshwater and terrestrial ecosystems: a review

The state of knowledge of contaminants in Canadian Arctic biota of the freshwater and terrestrial ecosystems has advanced enormously since the publication of the first major reviews by Lockhart et al. and Thomas et al. in The Science of the Total Environment in 1992. The most significant gains are new knowledge of spatial trends of organochlorines and heavy metal contaminants in terrestrial animals, such as caribou and mink, and in waterfowl, where no information was previously available. Spatial trends in freshwater fish have been broadened, especially in the Yukon, where contaminant measurements of, for example, organochlorines were previously non-existent. A review of contaminants data for fish from the Northwest Territories, Yukon and northern Quebec showed mercury as the one contaminant which consistently exceeds guideline limits for subsistence consumption or commercial sale. Lake trout and northern pike in the Canadian Shield lakes of the Northwest Territories and northern Quebec generally had the most elevated levels. Levels of other heavy metals were generally not elevated in fish. Toxaphene was the major organochlorine contaminant in all fish analyzed. The concentrations of organochlorine contaminants in fish appear to be a function not only of trophic level but of other aspects of the lake ecosystem. Among Arctic terrestrial mammals, PCBs and cadmium were the most prominent contaminants in the species analyzed. Relatively high levels (10-60 micrograms g-1) of cadmium were observed in kidney and liver of caribou from the Yukon, the Northwest Territories and northern Quebec, with concentrations in western herds being higher than in those from the east. For the organochlorine contaminants, a west to east increase in zigma PCBs, HCB and zigma HCH was found in caribou, probably as a result of the predominant west to east/north-east atmospheric circulation pattern which delivers these contaminants from industrialized regions of central and eastern North America to the Arctic via long-range atmospheric transport. Radiocesium contamination of lichens and caribou has continued to decrease. Significant contamination by PCBs and lead of soils and vascular plants was observed in the immediate vicinity and within a 20-km radius of DEW line sites in the Canadian Arctic. There was also evidence for transfer of PCBs from plants to lemmings. There was no evidence, however, that large mammals such as caribou living in the general area of the DEW line sites had elevated levels of PCBs. There is very limited temporal trend information for most contaminants in biota of Arctic terrestrial and freshwater environments.

Spatial and temporal trends and effects of contaminants in the Canadian Arctic marine ecosystem: a review

Recent studies have added substantially to our knowledge of spatial and temporal trends of persistent organic pollutants and heavy metals in the Canadian Arctic marine ecosystem. This paper reviews the current state of knowledge of contaminants in marine biota in the Canadian Arctic and where possible, discusses biological effects. The geographic coverage of information on contaminants such as persistent organochlorines (OCs) (PCBs, DDT- and chlordane-related compounds, hexachlorocyclohexanes, toxaphene) and heavy metals (mercury, selenium, cadmium, lead) in tissues of marine mammal and sea birds is relatively complete. All major beluga, ringed seal and polar bear stocks along with several major sea bird colonies have been sampled and analysed for OC and heavy metal contaminants. Studies on contaminants in walrus are limited to Foxe Basin and northern Québec stocks, while migratory harp seals have only been studied recently at one location. Contaminant measurements in bearded seal, harbour seal, bowhead whale and killer whale tissues from the Canadian Arctic are very limited or non-existent. Many of the temporal trend data for contaminants in Canadian Arctic biota are confounded by changes in analytical methodology, as well as by variability due to age/size, or to dietary and population shifts. Despite this, studies of OCs in ringed seal blubber at Holman Island and in sea birds at Prince Leopold Island in Lancaster Sound show declining concentrations of PCBs and DDT-related compounds from the 1970s to 1980s then a levelling off during the 1980s and early 1990s. For other OCs, such as chlordane, HCH and toxaphene, limited data for the 1980s to early 1990s suggests few significant declines in concentrations in marine mammals or sea birds. Temporal trend studies of heavy metals in ringed seals and beluga found higher mean concentrations of mercury in more recent (1993/1994) samples than in earlier collections (1981-1984 in eastern Arctic, 1972-1973 in western Arctic) for both species. Rates of accumulation of mercury are also higher in present day animals than 10-20 years ago. Cadmium concentrations in the same animals (eastern Arctic only) showed no change over a 10-year period. No temporal trend data are available for metals in sea birds or polar bears. There have been major advances in knowledge of specific biomarkers in Canadian Arctic biota over the past few years. The species with the most significant risk of exposure to PCBs and OC pesticides may be the polar bear which, based on comparison with EROD activity in other marine mammals (beluga, ringed seal), appears to have elevated CYP1A-mediated activity. The MFO enzyme data for polar bear, beluga and seals suggest that even the relatively low levels of contaminants present in Arctic animals may not be without biological effects, especially during years of poor feeding.

Diffusion tensor MR imaging and comparative histology of glioma engrafted in the rat spinal cord

MR imaging using contrast material derived from the diffusion of tissue water was tested for its ability to provide a nondestructive histologic analysis of tumor morphology. An apparent diffusion tensor MR image of a glioma engrafted within a rat spinal cord was generated in which fiber orientation in three dimensions was displayed in color. This imaging method clearly separated tumor from host white and gray matter and corresponded well with conventional histologic microscopy.

Long-term actions of vector-derived nerve growth factor or brain-derived neurotrophic factor on choline acetyltransferase and Trk receptor levels in the adult rat basal forebrain

Trophic factor gene therapy may provide a rational treatment strategy for neurodegenerative disease. Recombinant adeno-associated virus vectors, incorporating a neuron-specific promoter driving bicistronic expression of green fluorescent protein and either nerve growth factor or brain-derived neurotrophic factor, transduced 10,000-15,000 neurons in the medial septum for periods of at least six months. Both cholinergic and non-cholinergic neurons expressed green fluorescent protein. Nerve growth factor and brain-derived neurotrophic factor vectors produced up to 50% increases in immunohistochemical detection of the acetylcholine-synthesizing enzyme in septal neurons ipsilateral to the injection. Increased levels of this enzyme, choline acetyltransferase, persisted for six months with the brain-derived neurotrophic factor vector. The nerve growth factor vector increased Trk receptor immunoreactivity in a volume of brain exceeding that of the transduced cells. Counterstaining for the neuronal marker, NeuN, or Nissl substance did not reveal any vector toxicity at any time-point. It therefore appears that the lasting effects of vector-mediated trophic factor gene transfer will offer a new approach for modulating septal cholinergic transmission and Trk receptor activity.

Degradation of chondroitin sulfate proteoglycan enhances the neurite-promoting potential of spinal cord tissue

The contribution of chondroitin sulfate proteoglycan (CSPG) in the suppression of axonal growth in rat spinal cord has been examined by means of an in vitro bioassay in which regenerating neurons are grown on tissue section substrata. Dissociated embryonic chick dorsal root ganglionic neurons were grown on normal and injured adult spinal cord tissue sections treated with chondroitinases. Neuritic growth on normal spinal cord tissue was meager. However, both the percentage of neurons with neurites and the average neurite length were substantially greater on sections treated with chondroitinase ABC. Enzymes that specifically degraded dermatan sulfate or hyaluronan were ineffective. Neuritic growth was significantly greater on injured (compared to normal) spinal cord and a further dramatic increase resulted from chondroitinase ABC treatment. Neurites grew equally within white and gray matter regions after chondroitinase treatment. Observed increases in neurite outgrowth on chondroitinase-treated tissues were largely inhibited in the presence of function-blocking laminin antibodies. These findings indicate that inhibitory CSPG is widely distributed and predominant in both normal and injured spinal cord tissues. Additionally, inhibitory CSPG is implicated in negating the potential stimulatory effects of laminin that might otherwise support spinal cord regeneration.

Characterization of a primary central nervous system atypical teratoid/rhabdoid tumor and derivative cell line: immunophenotype and neoplastic properties

Primary central nervous system (CNS) atypical teratoid/malignant rhabdoid tumors (ATT/RhT) occur during early childhood and are almost invariably fatal. Expression of multiple phenotypes in ATT/RhT suggests the presence of an undifferentiated progenitor with the potential to differentiate along multiple lines. These properties have made it difficult to characterize the etiology and histogenesis of these tumors and complicate efforts to develop targeted therapies. This paper characterizes the immunophenotype of a human CNS ATT/RhT and describes the properties of a derivative cell line (Atrt95) which retained morphological and immunochemical characteristics of the parent tumor including diverse differentiation. Most tumor cells were strongly immunoreactive for glial fibrillary acidic protein, vimentin and A2B5. Scattered, large tumor cells that showed a rhabdoid phenotype were immunoreactive for synaptophysin. The morphology of cultured Atrt95 cells was heterogeneous, but often fit into 1 of 3 classes that appeared to correspond to cell populations observed within the parent tumor including: 1) tightly-packed small-cell colonies, 2) large, well-spread highly motile cells and 3) arrays of elongated cells. In vitro assays demonstrated that growth of the entire culture was anchorage-dependent but not serum-dependent. Transplantation of Atrt95 cells into the rat spinal cord resulted in tumor growth and CNS invasion. Preliminary cytogenetics study revealed complex aneuploidy but no apparent monosomy or deletions of chromosome 22. The immunophenotype of this neoplasm and derivative cell line is consistent with a primitive glioneuronal lineage and its in vitro characteristics are that of an invasive malignancy similar to the naturally occurring tumor. This unique cell line (Atrt95) provides a valuable model to study the biology and genetics of the CNS ATT/RhT.

Children's use of triadic eye gaze information for "mind reading"

Five experiments examined children's use of eye gaze information for "mind-reading" purposes, specifically, for inferring another person's desire. When presented with static displays in the first 3 experiments, only by 4 years of age did children use another person's eye direction to infer desires, although younger children could identify the person's focus of attention. Further, 3-year-olds were capable of inferring desire from other nonverbal cues, such as pointing (Experiment 3). When eye gaze was presented dynamically with several other scaffolding cues (Experiment 4), 2- and 3-year-olds successfully used eye gaze for desire inference. Scaffolding cues were removed in Experiment 5, and 2- and 3-year-olds still performed above chance in using eye gaze. Results suggest that 2-year-olds are capable of using eye gaze alone to infer about another's desire. The authors propose that the acquisition of the ability to use attentional cues to infer another's mental state may involve both an association process and a differentiation process.