Comparison of [11C]UCB-J and [18F]FDG PET in Alzheimer's disease: A tracer kinetic modeling study

[11C]UCB-J PET for synaptic vesicle glycoprotein 2 A (SV2A) has been proposed as a suitable marker for synaptic density in Alzheimer's disease (AD). We compared [11C]UCB-J binding for synaptic density and [18F]FDG uptake for metabolism (correlated with neuronal activity) in 14 AD and 11 cognitively normal (CN) participants. We assessed both absolute and relative outcome measures in brain regions of interest, i.e., K1 or R1 for [11C]UCB-J perfusion, VT (volume of distribution) or DVR to cerebellum for [11C]UCB-J binding to SV2A; and Ki or KiR to cerebellum for [18F]FDG metabolism. [11C]UCB-J binding and [18F]FDG metabolism showed a similar magnitude of reduction in the medial temporal lobe of AD -compared to CN participants. However, the magnitude of reduction of [11C]UCB-J binding in neocortical regions was less than that observed with [18F]FDG metabolism. Inter-tracer correlations were also higher in the medial temporal regions between synaptic density and metabolism, with lower correlations in neocortical regions. [11C]UCB-J perfusion showed a similar pattern to [18F]FDG metabolism, with high inter-tracer regional correlations. In summary, we conducted the first in vivo PET imaging of synaptic density and metabolism in the same AD participants and reported a concordant reduction in medial temporal regions but a discordant reduction in neocortical regions.

Effect of age on brain metabotropic glutamate receptor subtype 5 measured with [18F]FPEB PET

OBJECTIVE

Metabotropic glutamate receptor subtype 5 (mGluR5) is integral to the brain glutamatergic system and cognitive function. This study investigated whether aging is associated with decreased brain mGluR5 availability.

METHODS

Cognitively normal participants (n = 45), aged 18 to 84 years, underwent [18F]FPEB positron emission tomography scans to quantify brain mGluR5. Distribution volume (VT) was computed using a venous or arterial input function and equilibrium modeling from 90 to 120 min. In the primary analysis, the association between age and VT in the hippocampus and association cortex was evaluated using a linear mixed model. Exploratory analyses assessed the association between age and VT in multiple brain regions. The contribution of gray matter tissue alterations and partial volume effects to associations with age was also examined.

RESULTS

In the primary analysis, older age was associated with lower [18F]FPEB binding to mGluR5 (P = 0.026), whereas this association was not significant after gray matter masking or partial volume correction to account for age-related tissue loss. Post hoc analyses revealed an age-related decline in mGluR5 availability in the hippocampus of 4.5% per decade (P = 0.007) and a non-significant trend in the association cortex (P = 0.085). An exploratory analysis of multiple brain regions revealed broader inverse associations of age with mGluR5 availability, but not after partial volume correction.

CONCLUSION

Reductions in mGluR5 availability with age appear to be largely mediated by tissue loss. Quantification of [18F]FPEB binding to mGluR5 may expand our understanding of age-related molecular changes and the relationship with brain tissue loss.

A177 METHOTREXATE FOR THE INDUCTION OF REMISSION IN ULCERATIVE COLITIS

Background

Obtaining steroid-free remission in Ulcerative Colitis (UC) is a clinically important parameter that can mitigate the development of disease-related complications and lead to improved quality of life.

Aims

A systematic review to assess the effects and safety of methotrexate for induction in patients with UC.

Methods

MEDLINE, EMBASE, CENTRAL were searched from inception to August 20, 2020. Randomized controlled trials (RCTs) comparing methotrexate with placebo or an active comparator in patients with active ulcerative colitis were considered for inclusion. The primary outcome measure was the proportion of patients who achieved clinical remission and withdrawal from steroids as defined by the studies and expressed as a percentage of the total number of patients randomized (intention-to-treat analysis). The overall quality of the evidence supporting the primary outcome was assessed using the GRADE criteria.

Results

Three studies (n=212) were included in the review. Two studies were randomized controlled trials comparing methotrexate to placebo for induction of remission of active ulcerative colitis. The first study (n = 67) compared oral methotrexate (12.5 mg/week) to placebo. Forty-seven percent (14/30) of methotrexate patients achieved clinical remission and complete withdrawal from steroids during the study period compared to 49% (18/37) of placebo patients (RR 0.96, 95% CI 0.58 to 1.59). A GRADE analysis indicated that the overall quality of the evidence supporting this outcome was low due to very sparse data. The second study (n=111) compared subcutaneous/intramuscular methotrexate 25 mg/week to placebo. The primary outcome, steroid-free remission at week 16, was present in 32% (19/60) of patients on methotrexate in comparison to 20%(10/51) of patients in the placebo arm (RR 1.62; 95% CI 0.83 to 3.15; P-value of 0.15). A GRADE analysis indicated downgrading of the evidence to low given very sparse data (29 events). An additional head-to-head randomised controlled study (n = 34) compared oral methotrexate (15 mg/week) to 6-mercaptopurine (1.5 mg/kg/day) and 5-aminosalicylic acid (3 g/day). This final study was judged to be at high risk of bias due to an open-label design. At 30 weeks, 58% (7/12) of methotrexate patients achieved clinical remission and withdrawal from steroids compared to 79% (11/14) of 6-mercaptopurine patients (RR 0.74, 95% CI 0.43 to 1.29) and 25% (2/8) of 5-aminosalicylic acid patients (RR 2.33, 95% CI 0.64 to 8.49). GRADE analyses indicated that the overall quality of the evidence was very low due to very sparse data and high risk of bias.

Conclusions

Methotrexate demonstrated no benefit over placebo or active comparators for the induction of steroid-free remission. Future research is ongoing to explore the utility of combination therapy with monoclonal antibody biologic therapy for the treatment of active ulcerative colitis.

Funding Agencies

None

Statin Use and Risk of Cognitive Decline in the ADNI Cohort

OBJECTIVE

To investigate associations between statin use and cognitive change, as well as diagnostic conversion, in individuals with cognitively normal (CN) status, mild cognitive impairment (MCI), and dementia due to Alzheimer disease (AD-dementia).

METHODS

A multicenter cohort study with 1629 adults 48 to 91 years old with CN status, early MCI (EMCI), late MCI (LMCI), or AD-dementia at baseline followed prospectively for 24 months. Statin use was assessed at baseline, and cognition was measured over time with a composite memory score, a composite executive function score, and a global cognition score (Alzheimer's Disease Assessment Scale). Conversion to a more impaired diagnostic category was determined by clinician assessment. Repeated measures linear mixed-effects models were used to evaluate associations between statin use and change in cognition over time. Cox proportional hazards models were used to evaluate associations between statin use and time to diagnostic conversion. All models were stratified by baseline diagnostic group.

RESULTS

Statin use was not associated with change in cognitive measures for CN, LMCI, or AD-dementia participants. Among EMCI participants, statin use was associated with a significantly slower rate of decline on the memory composite, but no other cognitive measure. Statin use was not associated with time to conversion for any diagnostic group.

CONCLUSIONS

This study did not support an association between statin use and diagnostic conversion but suggested a possible association between statin use and cognitive change in EMCI. Additional randomized clinical trials of statins may be warranted in the prodromal EMCI stage of AD.

PET imaging of mGluR5 in Alzheimer's disease

BACKGROUND

Metabotropic glutamate subtype 5 receptors (mGluR5) modulate synaptic transmission and may constitute an important therapeutic target in Alzheimer's disease (AD) by mediating the synaptotoxic action of amyloid-β oligomers. We utilized the positron emission tomography (PET) radioligand [18F]FPEB to investigate mGluR5 binding in early AD.

METHODS

Sixteen individuals with amnestic mild cognitive impairment (MCI) due to AD or mild AD dementia who were positive for brain amyloid were compared to 15 cognitively normal (CN) participants who were negative for brain amyloid. Diagnostic groups were well balanced for age, sex, and education. Dynamic PET scans were acquired for 60 min, starting at 60 min after the initial administration of up to 185 MBq of [18F]FPEB using a bolus-plus-constant-infusion method (Kbol = 190 min). Equilibrium modeling with a cerebellum reference region was used to estimate [18F]FPEB binding (BPND) to mGluR5. Analyses were performed with and without corrections for gray matter atrophy and partial volume effects.

RESULTS

Linear mixed model analysis demonstrated a significant effect of group (p = 0.011) and the group × region interaction (p = 0.0049) on BPND. Post hoc comparisons revealed a significant reduction (43%) in mGluR5 binding in the hippocampus of AD (BPND = 0.76 ± 0.41) compared to CN (BPND = 1.34 ± 0.58, p = 0.003, unpaired t test) participants, and a nonsignificant trend for a reduction in a composite association cortical region in AD (BPND = 1.57 ± 0.25) compared to CN (BPND = 1.86 ± 0.63, p = 0.093) participants. Exploratory analyses suggested additional mGluR5 reductions in the entorhinal cortex and parahippocampal gyrus in the AD group. In the overall sample, hippocampal mGluR5 binding was associated with episodic memory scores and global function.

CONCLUSIONS

[18F]FPEB-PET revealed reductions in hippocampal mGluR5 binding in early AD. Quantification of mGluR5 binding in AD may expand our understanding of AD pathogenesis and accelerate the development of novel biomarkers and treatments.

Assessing Synaptic Density in Alzheimer Disease With Synaptic Vesicle Glycoprotein 2A Positron Emission Tomographic Imaging

Importance

Synaptic loss is well established as the major structural correlate of cognitive impairment in Alzheimer disease (AD). The ability to measure synaptic density in vivo could accelerate the development of disease-modifying treatments for AD. Synaptic vesicle glycoprotein 2A is an essential vesicle membrane protein expressed in virtually all synapses and could serve as a suitable target for synaptic density.

Objective

To compare hippocampal synaptic vesicle glycoprotein 2A (SV2A) binding in participants with AD and cognitively normal participants using positron emission tomographic (PET) imaging.

Design, Setting, and Participants

This cross-sectional study recruited 10 participants with AD and 11 participants who were cognitively normal between November 2015 and June 2017. We hypothesized a reduction in hippocampal SV2A binding in AD, based on the early degeneration of entorhinal cortical cell projections to the hippocampus (via the perforant path) and hippocampal SV2A reductions that had been observed in postmortem studies. Participants underwent high-resolution PET scanning with ((R)-1-((3-(11C-methyl-11C)pyridin-4-yl)methyl)-4-(3,4,5-trifluorophenyl)pyrrolidin-2-one), a compound more commonly known as 11C-UCB-J, for SV2A. They also underwent high-resolution PET scanning with carbon 11-labeled Pittsburgh Compound B (11C-PiB) for β-amyloid, magnetic resonance imaging, and cognitive and neurologic evaluation.

Main Outcomes and Measures

Outcomes were 11C-UCB-J-specific binding (binding potential [BPND]) via PET imaging in brain regions of interest in participants with AD and participants who were cognitively normal.

Results

Ten participants with AD (5 male and 5 female; mean [SD] age, 72.7 [6.3] years; 10 [100%] β-amyloid positive) were compared with 11 participants who were cognitively normal (5 male and 6 female; mean [SD] age, 72.9 [8.7] years; 11 [100%] β-amyloid negative). Participants with AD spanned the disease stages from amnestic mild cognitive impairment (n = 5) to mild dementia (n = 5). Participants with AD had significant reduction in hippocampal SV2A specific binding (41%) compared with cognitively normal participants, as assessed by 11C-UCB-J-PET BPND (cognitively normal participants: mean [SD] BPND, 1.47 [0.37]; participants with AD: 0.87 [0.50]; P = .005). These reductions remained significant after correction for atrophy (ie, partial volume correction; participants who were cognitively normal: mean [SD], 2.71 [0.46]; participants with AD: 2.15 [0.55]; P = .02). Hippocampal SV2A-specific binding BPND was correlated with a composite episodic memory score in the overall sample (R = 0.56; P = .01).

Conclusions and Relevance

To our knowledge, this is the first study to investigate synaptic density in vivo in AD using 11C-UCB-J-PET imaging. This approach may provide a direct measure of synaptic density, and it therefore holds promise as an in vivo biomarker for AD and as an outcome measure for trials of disease-modifying therapies, particularly those targeted at the preservation and restoration of synapses.

Sleep Disturbance and the Risk of Cognitive Decline or Clinical Conversion in the ADNI Cohort

BACKGROUND

We investigated the relationship between sleep disturbance and cognitive decline or clinical conversion in individuals with normal cognition (CN), as well as those with mild cognitive impairment (MCI) and dementia due to Alzheimer disease (AD-dementia).

METHODS

Secondary analysis of 1,629 adults between 48 and 91 years of age with up to 24 months of follow-up from the ADNI (Alzheimer's Disease Neuroimaging Initiative), a longitudinal cohort study.

RESULTS

Sleep disturbance was not associated with decline in memory, executive function, or global cognition. The presence of sleep disturbance did not significantly increase the risk of diagnostic conversion in CN, early MCI, or late MCI participants.

CONCLUSION

This study investigated the effect of sleep disturbance on cognitive decline using several outcomes and does not support the hypothesis that sleep disturbance predicts subsequent cognitive decline.

Poststroke subgranular and rostral subventricular zone proliferation in a mouse model of neonatal stroke

Stroke in the neonatal brain is an understudied cause of neurologic morbidity. Recently we have characterized a new immature mouse model of stroke utilizing unilateral carotid ligation alone to produce infarcts and acute seizures in postnatal day 12 (P12) CD-1 mice. In this study, the amount of poststroke neural progenitor proliferation was examined in the subgranular (SGZ) of the dentate gyrus and the subventricular zone (SVZ) 7, 14, and 21days after ischemia (DAI). A single IP injection (50 mg/kg) of bromodeoxyuridine (BrdU) given 2 hr before perfusion fixation labeled newborn cells. Early cell phenotypes were quantified by colabeling with GFAP, nestin, and DCX. Control mice revealed an age-dependent decrease in neural proliferation, with an approximately 50% drop in BrdU-labeled cell counts at P33 compared with P19 both in the SGZ and in the SVZ. Significant reduction in the amount of neural proliferation in the ipsilateral injured SGZ of ligated mice correlated with both the severity of the stroke-injury and the acute seizure scores. Similar correlations were not detected contralaterally. Contralateral SGZ neural proliferation was initially lowered at 7 DAI but normalized by 21 DAI. In both injured and control brains, approximately 90% of newborn SGZ cells colabeled with nestin, approximately 30% colabeled with GFAP, and a few colabeled with DCX. In contrast, poststroke SVZ cell proliferation was enhanced ipsi- more than contralaterally at 7 DAI. In the SVZ, the enhanced neural proliferation normalized to control levels by P33. In conclusion, the neural cell proliferation was differentially altered in the SGZ vs. SVZ after neonatal stroke.

Unintended changes in cognition, mood, and behavior arising from cell-based interventions for neurological conditions: ethical challenges

The prospect of using cell-based interventions (CBIs) to treat neurological conditions raises several important ethical and policy questions. In this target article, we focus on issues related to the unique constellation of traits that characterize CBIs targeted at the central nervous system. In particular, there is at least a theoretical prospect that these cells will alter the recipients' cognition, mood, and behavior-brain functions that are central to our concept of the self. The potential for such changes, although perhaps remote, is cause for concern and careful ethical analysis. Both to enable better informed consent in the future and as an end in itself, we argue that early human trials of CBIs for neurological conditions must monitor subjects for changes in cognition, mood, and behavior; further, we recommend concrete steps for that monitoring. Such steps will help better characterize the potential risks and benefits of CBIs as they are tested and potentially used for treatment.

Cell-based interventions for neurologic conditions: ethical challenges for early human trials

BACKGROUND

Attempts to translate basic stem cell research into treatments for neurologic diseases and injury are well under way. With a clinical trial for one such treatment approved and in progress in the United States, and additional proposals under review, we must begin to address the ethical issues raised by such early forays into human clinical trials for cell-based interventions for neurologic conditions.

METHODS

An interdisciplinary working group composed of experts in neuroscience, cell biology, bioethics, law, and transplantation, along with leading disease researchers, was convened twice over 2 years to identify and deliberate on the scientific and ethical issues raised by the transition from preclinical to clinical research of cell-based interventions for neurologic conditions.

RESULTS

While the relevant ethical issues are in many respects standard challenges of human subjects research, they are heightened in complexity by the novelty of the science, the focus on the CNS, and the political climate in which the science is proceeding.

CONCLUSIONS

Distinctive challenges confronting US scientists, administrators, institutional review boards, stem cell research oversight committees, and others who will need to make decisions about work involving stem cells and their derivatives and evaluate the ethics of early human trials include evaluating the risks, safety, and benefits of these trials, determining and evaluating cell line provenance, and determining inclusion criteria, informed consent, and the ethics of conducting early human trials in the public spotlight. Further study and deliberation by stakeholders is required to move toward professional and institutional policies and practices governing this research.

Unfractionated or low-molecular weight heparin for induction of remission in ulcerative colitis

BACKGROUND

There are a limited number of treatment options for patients with ulcerative colitis (UC). An increased risk of thrombosis in UC coupled with an observation that UC patients being treated with anticoagulant therapy for thrombotic events had an improvement in their bowel symptoms led to trials examining the use of unfractionated heparin (UFH) and low molecular weight heparins (LMWH) in patients with active UC.

OBJECTIVES

To review randomized trials examining the efficacy of unfractionated heparin (UFH) or low molecular weight heparins (LMWH) for remission induction in patients with ulcerative colitis.

SEARCH STRATEGY

The MEDLINE (PUBMED), and EMBASE databases, The Cochrane Central Register of Controlled Trials, the Cochrane IBD/FBD group specialized trials register, review papers on ulcerative colitis, and references from identified papers were searched in an effort to identify all randomized trials studying UFH or LMWH use in patients with ulcerative colitis. Abstracts from major gastroenterological meetings were searched to identify research published in abstract form only.

SELECTION CRITERIA

Each author independently reviewed potentially relevant trials to determine their eligibility for inclusion based on the criteria identified above. The Jadad scale was used to assess study quality. Studies published in abstract form only were included if the authors could be contacted for further information.

DATA COLLECTION AND ANALYSIS

A data extraction form was developed and used to extract data from included studies. At least 2 authors independently extracted data. Any disagreements were resolved by consensus. Data were analyzed using Review Manager (RevMan 4.2.9). Data were analyzed on an intention-to-treat basis, and treated dichotomously. In cross-over studies, only data from the first arm were included. The primary endpoint was induction of remission, as defined by the studies. Data were combined for analysis if they assessed the same treatments (UFH or LMWH versus placebo or other therapy). If a comparison was only assessed in a single trial, P-values were derived using the chi-square test. If the comparison was assessed in more than one trial, summary test statistics were derived using the Peto odds ratio and 95% confidence intervals (95% CI). The presence of heterogeneity among studies was assessed using the chi-square test (a P value of 0.10 was regarded as statistically significant). If statistically significant heterogeneity was identified the odds ratio and 95% CI were calculated using a random effects model.

MAIN RESULTS

There were 2 randomized, double-blind studies assessing LMWH versus placebo for the treatment of mild-moderate active UC. Various outcomes were assessed in the 2 studies. LMWH showed no benefit over placebo in any outcome, including clinical remission (OR 1.09; 95% CI 0.26 to 4.63; P = 0.91), clinical improvement (OR 0.73; 95% CI 0.32 to 1.66; P = 0.45 and OR 1.09; 95% CI 0.18 to 6.58; P = 0.92 in the two studies, respectively), endoscopic improvement (OR 1.35; 95% CI 0.29 to 6.18; P = 0.70), or histological improvement (OR 2.00; 95% CI 0.45 to 8.96; P = 0.37). LMWH was also not beneficial when added to standard therapy in a randomized open-label trial in which the outcome measures included clinical remission (OR 0.71; 95% CI 0.17 to 2.95; P = 0.64), clinical improvement (OR 2.00; 95% CI 0.31 to 12.75; P = 0.46), endoscopic remission (OR 0.71; 95% CI 0.17 to 2.95; P = 0.64), or endoscopic improvement (OR 1.40; 95% CI 0.34 to 5.79; P = 0.64). LMWH was well-tolerated and provided no significant benefit for quality of life. One study examining UFH versus corticosteroids in the treatment of severe UC demonstrated inferiority of UFH in clinical improvement as an outcome measure (OR 0.02; 95% CI 0 to 0.40; P = 0.01). Patients assigned to UFH did not improve clinically. More patients assigned to UFH had rectal hemorrhage as an adverse event.

AUTHORS' CONCLUSIONS

There is no evidence to support the use of UFH or LMWH for the treatment of active UC. No further trials examining these drugs for patients with UC are warranted, except perhaps a trial of UFH in patients with mild disease. Any benefit found would need to be weighed against a possible increased risk of rectal bleeding in patients with active UC.

Neurogenesis and neuronal commitment following ischemia in a new mouse model for neonatal stroke

Stroke in the neonatal brain is an important cause of neurologic morbidity. To characterize the dynamics of neural progenitor cell proliferation and maturation after survival delays in the neonatal brain following ischemia, we utilized unilateral carotid ligation alone to produce infarcts in postnatal day 12 CD1 mice. We investigated the neurogenesis derived from the sub-ventricular zone and the sub-granular zone of the dentate gyrus subsequent to injury. Newly produced cells were labeled by bromodeoxyuridine at approximately 1 week (P18-20) after the insult by 5 i.p. injections (each 50 mg/kg). Subsequent migration and differentiation of the newborn cells was investigated at postnatal day 40 by immunohistochemistry for molecular neuronal and glial cell-lineage markers and BrdU incorporation. Cresyl violet stain demonstrated massive loss of neurons in the ipsilateral septal hippocampus in the CA3 and CA1 regions associated with atrophy. Total counts of new cells were significantly lowered not only in the ipsilateral injured but also the contralateral uninjured hippocampi and correlated with the lesion induced atrophy. Bilateral percent neuronal commitments in the dentate gyri however, were not significantly different from control. New cell densities in the neocortex and striatum increased bilaterally after neonatal stroke. The predominantly non-neuronal commitment of the SVZ-derived new cells was similar to the percentage of non-neuronal commitment in controls. In conclusion, neurogenesis occurring at 1 week after neonatal ischemia in the model maintained cell-lineage commitment patterns similar to sham controls. However, the total number of hippocampal SGZ-derived new neurons was reduced bilaterally; in contrast, the SVZ-derived neurogenesis was amplified.

The research priorities of patients attending UK cancer treatment centres: findings from a modified nominal group study

Members of the public are increasingly consulted over health care and research priorities. Patient involvement in determining cancer research priorities, however, has remained underdeveloped. This paper presents the findings of the first consultation to be conducted with UK cancer patients concerning research priorities. The study adopted a participatory approach using a collaborative model that sought joint ownership of the study with people affected by cancer. An exploratory, qualitative approach was used. Consultation groups were the main method, combining focus group and nominal group techniques. Seventeen groups were held with a total of 105 patients broadly representative of the UK cancer population. Fifteen areas for research were identified. Top priority areas included the impact cancer has on life, how to live with cancer and related support issues; risk factors and causes of cancer; early detection and prevention. Although biological and treatment related aspects of science were identified as important, patients rated the management of practical, social and emotional issues as a higher priority. There is a mismatch between the research priorities identified by participants and the current UK research portfolio. Current research activity should be broadened to reflect the priorities of people affected by the disease.

Radiation-driven hydrodynamics of high- hohlraums on the national ignition facility

The first hohlraum experiments on the National Ignition Facility (NIF) using the initial four laser beams tested radiation temperature limits imposed by plasma filling. For a variety of hohlraum sizes and pulse lengths, the measured x-ray flux shows signatures of filling that coincide with hard x-ray emission from plasma streaming out of the hohlraum. These observations agree with hydrodynamic simulations and with an analytical model that includes hydrodynamic and coronal radiative losses. The modeling predicts radiation temperature limits with full NIF (1.8 MJ), greater, and of longer duration than required for ignition hohlraums.

Surface charge compensation for a highly charged ion emission microscope

A surface charge compensation electron flood gun has been added to the Lawrence Livermore National Laboratory (LLNL) highly charged ion (HCI) emission microscope. HCI surface interaction results in a significant charge residue being left on the surface of insulators and semiconductors. This residual charge causes undesirable aberrations in the microscope images and a reduction of the time-of-flight (T-O-F) mass resolution when studying the surfaces of insulators and semiconductors. The benefits and problems associated with HCI microscopy and recent results of the electron flood gun-enhanced HCI microscope are discussed.

Neurons derived from embryonic stem (ES) cells resemble normal neurons in their vulnerability to excitotoxic death

We determined whether embryonic stem (ES) cells could provide a model system for examining neuronal death mediated by glutamate receptors. Although limited evidence indicates that normal neurons can be derived from mouse ES cells, there have been no studies examining pathophysiological responses in mouse ES cell systems. Mouse ES cells, induced down a neural lineage by retinoic acid (RA), were found to have enhanced long-term survival when plated onto a layer of cultured mouse cortical glial cells. In these conditions, the ES cells differentiated into neural cells that appeared normal morphologically and displayed normal features of immunoreactivity when tested for neuron-specific elements. Varying the culture medium generated cultures of mixed neuronal/glial cells or enriched in oligodendrocytes. These cultures were viable for at least four weeks. Real-time PCR analysis of N-methyl-D-aspartate (NMDA) receptor subunits revealed an appropriate age-in-vitro dependent pattern of expression. Neurons derived from ES cells were vulnerable to death induced by a 24-h exposure to the selective glutamate receptor agonists NMDA, kainate, and alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA). This vulnerability to agonist-induced death increased with age in vitro, and related closely to expression of receptor subunits, as it does in cultured primary neurons. Experiments with selective receptor antagonists showed that glutamate receptors mediated the NMDA- and kainate-induced death. Neuronal differentiated ES cells therefore exhibited an excitotoxic response resembling that displayed by central nervous system (CNS) neurons. Thus, ES cells, which are very amenable to genetic manipulation, provide a valid system for studying glutamate receptor-mediated toxicity at the molecular level.

The impact of rural-urban migration on under-two mortality in India

This paper examines the impact of rural-urban migration on under-two mortality in India, using data from the 1992/93 Indian National Family Health Survey. Multilevel logistic models are fitted for mortality in three age groups: neonatal, early post-neonatal, and late post-neonatal and toddler. Migration status was not a significant determinant of mortality in any of the three age groups. Further analysis shows that a relationship between migration status and mortality exists when socioeconomic and health utilization variables are omitted from the models. The relationship between migration and mortality is thus explained by differences in socioeconomic status and use of health services between rural-urban migrant and nonmigrant groups. The selectivity of rural-urban migrants on socioeconomic characteristics creates mortality differentials between rural-urban migrants and rural non-migrants. Problems faced by migrants in assimilating into urban societies create mortality differentials between rural-urban migrants and urban non-migrants. These results highlight the need to target migrants in the provision of health services, and demonstrate that rural areas continue to have the highest levels of infant-child mortality. Further research is needed to understand the health care needs of rural-urban migrants in order to inform the provision of appropriate health care.

Methotrexate for induction of remission in refractory Crohn's disease

BACKGROUND

Although corticosteroids are effective for induction of remission of Crohn's disease, approximately 20% of patients who respond relapse when steroids are withdrawn and become steroid dependent (Binder 1985). Furthermore, corticosteroids exhibit significant adverse effects. The success of methotrexate as a treatment for rheumatoid arthritis led to its evaluation in patients with refractory Crohn's disease. Methotrexate has been studied for induction of remission of refractory Crohn's disease and has become the principal alternative to azathioprine/6MP therapy. The evidence for its effectiveness has not been subjected to a systematic review.

OBJECTIVES

To conduct a systematic review of the evidence for effectiveness of methotrexate for induction of remission in patients with active Crohn's disease in the presence and absence of concomitant steroid therapy.

SEARCH STRATEGY

A computer-assisted search of MEDLINE and EMBASE for relevant studies published in English, French, Spanish, Italian and German between 1966 and June 2002. Manual searches of reference lists from potentially relevant papers were performed to identify additional studies. The Cochrane Controlled Trials Register and the IBD Review Group Specialized Trials Register were also searched.

SELECTION CRITERIA

Randomized controlled trials involving patients of age > 17 years with refractory Crohn's disease defined by conventional clinical, radiological and endoscopic criteria, which was categorized as being active (Crohn's disease activity index >150).

OUTCOME MEASURES

The outcome measure was the rate of induction of remission and complete withdrawal from steroids in the treatment and control groups after 16 weeks of treatment. A secondary outcome was induction of remission with reduction in steroid dose of at least 50%. Selection of trials: The results of the searches above were reviewed independently by two observers and relevant studies selected according to the predefined selection criteria. Any disagreement among reviewers was resolved by consensus. The same two reviewers assessed the methodological quality of each trial (details of randomization method, including whether intention-to-treat analysis was possible from the published data, number of patients lost to follow-up, and if a blinded outcome assessment was used). A standard data extraction form was used. Appropriateness of combining results: Trials were first reviewed to assess the clinical comparability of trial protocols and study populations.

MAIN RESULTS

Three randomized placebo-controlled trials were identified. The three studies differed with respect to participants, intervention, and outcomes to the extent that it was considered to be inappropriate to combine the data statistically. Two studies which employed low doses of methotrexate orally showed no statistically significant difference between methotrexate and placebo treated patients, and one which employed a higher dose intramuscularly showed substantial benefit (number needed to treat, NNT=5). Adverse effects were more common with high dose intramuscular methotrexate therapy than with placebo.

REVIEWER'S CONCLUSIONS

There is evidence from a single large randomized trial on which to recommend the use of methotrexate 25 mg intramuscularly weekly for induction of remission and complete withdrawal from steroids in patients with refractory Crohn's disease. Although adverse effects are more common than with placebo, they were not severe. There is no evidence on which to base a recommendation for use of lower dose oral methotrexate.

Spinal cord injury

PURPOSE

This article is an overview of the newer therapeutic interventions employed in the care of the spinal cord injured individual and the theoretical rationale supporting them.

ISSUE

Spinal Cord Injury (SCI) care was, until recently, a maintenance type treatment, addressing systems mostly affected by complications of the original injury (e.g. bladder, skin, spasiticity).

CONCLUSION

With the recent advances in the neuroscience field, more aggressive interventions geared at secondary injury prevention, neuronal regeneration and functional restoration are emerging.

At the interface: convergence of neural regeneration and neural prostheses for restoration of function

The rapid pace of recent advances in development and application of electrical stimulation of the nervous system and in neural regeneration has created opportunities to combine these two approaches to restoration of function. This paper relates the discussion on this topic from a workshop at the International Functional Electrical Stimulation Society. The goals of this workshop were to discuss the current state of interaction between the fields of neural regeneration and neural prostheses and to identify potential areas of future research that would have the greatest impact on achieving the common goal of restoring function after neurological damage. Identified areas include enhancement of axonal regeneration with applied electric fields, development of hybrid neural interfaces combining synthetic silicon and biologically derived elements, and investigation of the role of patterned neural activity in regulating various neuronal processes and neurorehabilitation. Increased communication and cooperation between the two communities and recognition by each field that the other has something to contribute to their efforts are needed to take advantage of these opportunities. In addition, creative grants combining the two approaches and more flexible funding mechanisms to support the convergence of their perspectives are necessary to achieve common objectives.

Evidence for highly charged ion Coulomb crystallization in multicomponent strongly coupled plasmas

Multicomponent non-neutral ion plasmas in a Penning trap consisting of Be(+) and highly charged Xe ions, having different mass-to-charge ratios than Be(+), are cooled to form strongly coupled plasmas by applying a laser-based collisional cooling scheme. The temperature of the plasma was determined from a Doppler broadened transition in Be(+). For the Xe ions, which are centrifugally separated from the Be, the Coulomb coupling parameter was estimated to be approximately 1000. Molecular dynamics simulations of the ion mixture show ordered structures, indicating crystallization of the Xe.

Association models for a multivariate binary response

Models for a multivariate binary response are parameterized by univariate marginal probabilities and dependence ratios of all orders. The w-order dependence ratio is the joint success probability of w binary responses divided by the joint success probability assuming independence. This parameterization supports likelihood-based inference for both regression parameters, relating marginal probabilities to explanatory variables, and association model parameters, relating dependence ratios to simple and meaningful mechanisms. Five types of association models are proposed, where responses are (1) independent given a necessary factor for the possibility of a success, (2) independent given a latent binary factor, (3) independent given a latent beta distributed variable, (4) follow a Markov chain, and (5) follow one of two first-order Markov chains depending on the realization of a binary latent factor. These models are illustrated by reanalyzing three data sets, foremost a set of binary time series on auranofin therapy against arthritis. Likelihood-based approaches are contrasted with approaches based on generalized estimating equations. Association models specified by dependence ratios are contrasted with other models for a multivariate binary response that are specified by odds ratios or correlation coefficients.

A comparison of methotrexate with placebo for the maintenance of remission in Crohn's disease. North American Crohn's Study Group Investigators

BACKGROUND

Patients with Crohn's disease often have relapses. Better treatments are needed for the maintenance of remission. Although methotrexate is an effective short-term treatment for Crohn's disease, its role in maintaining remissions is not known.

METHODS

We conducted a double-blind, placebo-controlled, multicenter study of patients with chronically active Crohn's disease who had entered remission after 16 to 24 weeks of treatment with 25 mg of methotrexate given intramuscularly once weekly. Patients were randomly assigned to receive either methotrexate at a dose of 15 mg intramuscularly once weekly or placebo for 40 weeks. No other treatments for Crohn's disease were permitted. We compared the efficacy of treatment by analyzing the proportion of patients who remained in remission at week 40. Remission was defined as a score of 150 or less on the Crohn's Disease Activity Index.

RESULTS

Forty patients received methotrexate, and 36 received placebo. At week 40, 26 patients (65 percent) were in remission in the methotrexate group, as compared with 14 (39 percent) in the placebo group (P=0.04; absolute reduction in the risk of relapse, 26.1 percent; 95 percent confidence interval, 4.4 percent to 47.8 percent). Fewer patients in the methotrexate group than in the placebo group required prednisone for relapse (11 of 40 [28 percent] vs. 21 of 36 [58 percent], P=0.01). None of the patients who received methotrexate had a severe adverse event; one patient in this group withdrew because of nausea.

CONCLUSIONS

In patients with Crohn's disease who enter remission after treatment with methotrexate, a low dose of methotrexate maintains remission.

Pulmonary alveolar proteinosis in association with household exposure to fibrous insulation material

We report the case of a 35-year-old woman who developed pulmonary alveolar proteinosis requiring multiple lavage treatments, in association with household exposure to ventilation system dust comprised at least partially by a cellulose fire-resistant fibrous insulation material. Scanning electron microscopy with energy-dispersive x-ray analysis documented the presence of spectral peaks consistent with the insulation material in transbronchial biopsy tissue. The patient showed symptomatic improvement once exposure to the insulation material had ceased. We believe that this case demonstrates an unusual association with pulmonary alveolar proteinosis. This case emphasizes the broad differential diagnosis for this histologic injury pattern and the need to thoroughly investigate environmental exposures in patients with unexplained pulmonary disease.

Embryonic stem cells differentiate into oligodendrocytes and myelinate in culture and after spinal cord transplantation

Demyelination contributes to the loss of function consequent to central nervous system (CNS) injury. Enhanced remyelination through transplantation of myelin-producing cells may offer a pragmatic approach to restoring meaningful neurological function. An unlimited source of cells suitable for such transplantation therapy can be derived from embryonic stem (ES) cells, which are both pluripotent and genetically flexible. In this paper we show that oligodendrocyte cultures can be reliably produced from retinoic acid-induced ES cells and that these oligodendrocytes can myelinate axons in vitro. Methods were further developed for generating highly enriched cultures of oligodendrocytes through an additional culturing step, producing an intermediate "oligosphere" stage. To test whether ES cells can survive, migrate, and differentiate into mature myelin-producing cells in areas of demyelination in the adult CNS, ES cells were transplanted into the dorsal columns of adult rat spinal cord 3 days after chemical demyelination. In the demyelination site, large numbers of ES cells survived and differentiated primarily into mature oligodendrocytes that were capable of myelinating axons. Furthermore, when oligosphere cells were transplanted into the spinal cords of myelin-deficient shiverer (shi/shi) mutant mice, the ES cell-derived oligodendrocytes migrated into the host tissue, produced myelin and myelinated host axons. These studies demonstrate the ability of ES cell-derived oligodendrocytes to myelinate axons in culture and to replace lost myelin in the injured adult CNS. Transplantation of ES cells may be a practical approach to treatment of primary and secondary demyelinating diseases in the adult CNS.

Transplanted embryonic stem cells survive, differentiate and promote recovery in injured rat spinal cord

Transplantation approaches using cellular bridges, fetal central nervous system cells, fibroblasts expressing neurotrophin-3 (ref. 6), hybridoma cells expressing inhibitory protein-blocking antibodies, or olfactory nerves ensheathing glial cells transplanted into the acutely injured spinal cord have produced axonal regrowth or functional benefits. Transplants of rat or cat fetal spinal cord tissue into the chronically injured cord survive and integrate with the host cord, and may be associated with some functional improvements. In addition, rats transplanted with fetal spinal cord cells have shown improvements in some gait parameters, and the delayed transplantation of fetal raphe cells can enhance reflexes. We transplanted neural differentiated mouse embryonic stem cells into a rat spinal cord 9 days after traumatic injury. Histological analysis 2-5 weeks later showed that transplant-derived cells survived and differentiated into astrocytes, oligodendrocytes and neurons, and migrated as far as 8 mm away from the lesion edge. Furthermore, gait analysis demonstrated that transplanted rats showed hindlimb weight support and partial hindlimb coordination not found in 'sham-operated' controls or control rats transplanted with adult mouse neocortical cells.

Selective activation of group II mGluRs with LY354740 does not prevent neuronal excitotoxicity

Recent reports have suggested a role for group II metabotropic glutamate receptors (mGluRs) in the attenuation of excitotoxicity. Here we examined the effects of the recently available group II agonist (+)-2-Aminobicyclo[3.1.0]hexane-2-6-dicarboxylic acid (LY354740) on N-methyl-D-aspartate (NMDA)-induced excitotoxic neuronal death, as well as on hypoxic-ischemic neuronal death both in vitro and in vivo. At concentrations shown to be selective for group II mGluRs expressed in cell lines (0.1-100 nM), LY354740 did not attenuate NMDA-mediated neuronal death in vitro or in vivo. Furthermore, LY354740 did not attenuate oxygen-glucose deprivation-induced neuronal death in vitro or ischemic infarction after transient middle cerebral artery occlusion in rats. In addition, the neuroprotective effect of another group II agonist, (S)-4-carboxy-3-phenylglycine (4C3HPG), which has shown injury attenuating effects both in vitro and in vivo, was not blocked by the group II antagonists (2 S)-alpha-ethylglutamic acid (EGLU), (RS)-alpha-methyl-4-sulphonophenylglycine (MSPG), or the group III antagonist (S)-alpha-methyl-3-carboxyphenylalanine (MCPA), suggesting that this neuroprotection may be mediated by other effects such as upon group I mGluRs.

Lack of effect of intravenous administration on time to respond to azathioprine for steroid-treated Crohn's disease. North American Azathioprine Study Group

BACKGROUND & AIMS

Azathioprine is effective for Crohn's disease but acts slowly. A loading dose may decrease the time to response.

METHODS

A placebo-controlled study was conducted in patients with active Crohn's disease despite prednisone treatment. Patients were randomized to a 36-hour infusion of azathioprine, 40 mg/kg (51 patients), or placebo (45 patients) followed by oral azathioprine, 2 mg/kg, for 16 weeks. Prednisone was tapered over 5 weeks. The primary outcome measure was complete remission at week 8, defined by discontinuation of prednisone and a Crohn's Disease Activity Index of </=150 points. Erythrocyte concentrations of the azathioprine active metabolite, 6-thioguanine nucleotide, were measured.

RESULTS

At week 8, 13 patients (25%) were in complete remission in the azathioprine-loaded group compared with 11 patients (24%) in the placebo group. The frequency of complete remission did not increase after 8 weeks in either group. Both groups achieved steady state of 6-thioguanine nucleotide by week 2, and no differences were found in mean concentrations between the groups. There were no significant differences in the frequency of adverse events between the groups.

CONCLUSIONS

A loading dose does not decrease the time to response in patients with steroid-treated Crohn's disease beginning azathioprine therapy. Steady state of erythrocyte 6-thioguanine nucleotide and complete response occurred earlier than previously reported.

Exact tests of goodness of fit of log-linear models for rates

We propose Metropolis-Hastings sampling methods for estimating the exact conditional p-value for tests of goodness of fit of log-linear models for mortality rates and standardized mortality ratios. We focus on two-way tables, where the required conditional distribution is a multivariate noncentral hypergeometric distribution with known noncentrality parameter. Two examples are presented: a 2 x 3 table, where the exact results, obtained by enumeration, are available for comparison, and a 9 x 7 table, where Monte Carlo methods provide the only feasible approach for exact inference.

Nuclear expression of p53, p21 and cyclin D1 is increased in bronchioloalveolar carcinoma

AIMS

The objectives of this study were: (1) to determine, using immunohistochemistry, the level of expression of the cell cycle factors p53, p21 and cyclin D1 in a group of bronchioloalveolar carcinomas (BACs), and to compare these data to relevant published data for lung carcinoma; (2) to determine if higher expression rates for these factors in BAC were associated statistically with advanced clinical stage, greater tumour size, tobacco abuse, and/or BAC subtype; (3) to seek, using Fisher's exact t-test and paired data groups, any significant associations within the expression data for p53, p21 and cyclin D1.

METHODS AND RESULTS

A panel of monoclonal antibodies against p53, p21 and cyclin D1 was applied to 19 bronchioloalveolar carcinomas (17 surgical pathology cases and two autopsies) from the tissue archives of St. Louis University. These immunohistochemical stains were graded on a semiquantitative scale according to the prevalence of nuclear staining within the tumour (< 10% positive cells = 0, 10-25% = 1+, 25-50% = 2+, 50-75% = 3+ and 75-100% = 4+). Six of 19 (32%) of BACs showed 1+ or greater p53 positivity, six of 19 (32%) showed 1+ or greater nuclear cyclin D1 positivity, and nine of 19 (47%) of BACs showed 1+ or greater p21 nuclear positivity. A statistically significant correlation was found between p53 and cyclin D1 expression (P = 0.046, Fisher's exact t-test), but not between p53 and p21, or between p21 and cyclin D1. No statistically significant association was found between the cell cycle factor expression data and subtype of BAC (mucinous vs. nonmucinous), tumour diameter, clinical stage or tobacco-use history.

CONCLUSIONS

BACs show p53 immunostain positivity at a frequency similar to that published for p53 mutations in lung adenocarcinomas in general. Cyclin D1 and p21 nuclear expression characterizes a significant proportion of BACs, with cyclin D1 and p53 expression showing a statistically significant association. Aberrations in p53, p21, and cyclin D1 expression may be important in the development of a significant proportion of BACs.

Multiple classes of the oligodendrocyte lineage are highly vulnerable to excitotoxicity

We have recently shown that galactocerebroside (Gal-C)-expressing oligodendrocytes are highly vulnerable to (AMPA)/kainate receptor-mediated death. Here we examined the vulnerability of cells at different developmental stages of the oligodendrocyte lineage to AMPA/kainate receptor-mediated excitotoxicity. Oligodendrocyte precursor cells, pre-oligodendrocytes and mature oligodendrocytes were killed by 24 h exposures to low concentrations of kainate (30-100 microM). Death was attenuated by the AMPA/kainate receptor antagonist 6-nitro-7-sulfamoylbenzo(f)quinoxaline-2,3-dione (NBQX). The high vulnerability of oligodendrocytes and their precursors to AMPA/kainate receptor excitotoxicity may represent an important mechanism of white matter damage resulting from trauma or ischemia in the perinatal and adult central nervous system (CNS).

Extracellular acidity potentiates AMPA receptor-mediated cortical neuronal death

The extracellular acidity that accompanies brain hypoxia-ischemia is known to reduce both NMDA and AMPA-kainate receptor-mediated currents and NMDA receptor-mediated neurotoxicity. Although a protective effect of acidic pH on AMPA-kainate receptor-mediated excitotoxicity has been assumed, such has not been demonstrated. Paradoxically, we found that lowering extracellular pH selectively increased AMPA-kainate receptor-mediated neurotoxicity in neocortical cell cultures, despite reducing peak elevations in intracellular free Ca2+. This injury potentiation may, at least in part, be related to a slowed recovery of intracellular Ca2+ homeostasis, observed after AMPA-kainate receptor activation, but not after NMDA receptor activation or exposure to high K+. The ability of acidic pH to selectively augment AMPA-kainate receptor-mediated excitotoxicity may contribute to the prominent role that these receptors play in selective neuronal death after transient global ischemia.

Role of glutamate receptor-mediated excitotoxicity in bilirubin-induced brain injury in the Gunn rat model

Severe hyperbilirubinemia in neonates with prematurity and/or systemic illnesses such as hemolytic disease, acidosis, and hypoxemia enhances their risk for developing cerebral palsy, paralysis of ocular upgaze, and deafness. This neurologic syndrome has been associated with selective neuronal vulnerability in the basal ganglia, certain brainstem nuclei, and Purkinje cells. However, the mechanism by which bilirubin damages neurons remains unclear. In these studies, we found that intracerebral injection of N-methyl-D-aspartate (NMDA), an excitotoxic analogue of glutamate, caused greater injury in jaundiced 7-day-old Gunn (jj) rat pups than in nonjaundiced heterozygous (Nj) littermate controls. NMDA injection caused even greater injury when protein-bound bilirubin was displaced with the sulfonamide drug sulfadimethoxine in jaundiced homozygous pups. In additional experiments, the acute signs of bilirubin-mediated neuronal injury, induced in homozygous (jj) Gunn rats by treatment with sulfonamide, were reduced by concurrent treatment with the NMDA-type glutamate channel antagonist (+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohept-5,10-imine (MK-801, dizocilpine). The results suggest that bilirubin may cause encephalopathy and neuronal injury, at least in part, through an NMDA receptor-mediated excitotoxic mechanism. This conclusion is consistent with clinical observations that bilirubin encephalopathy is synergistically worsened by hypoxemia, which also shares an excitotoxic mechanism of neuronal injury.

Oligodendrocytes from forebrain are highly vulnerable to AMPA/kainate receptor-mediated excitotoxicity

Little is known of the molecular mechanisms that trigger oligodendrocyte death and demyelination in many acute central nervous system insults. Since oligodendrocytes express functional alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)/kainate-type glutamate receptors, we examined the possibility that oligodendrocyte death can be mediated by glutamate receptor overactivation. Oligodendrocytes in primary cultures from mouse forebrain were selectively killed by low concentrations of AMPA, kainate or glutamate, or by deprivation of oxygen and glucose. This toxicity could be blocked by the AMPA/kainate receptor antagonist 6-nitro-7-sulfamoylbenzo(f)quinoxaline-2,3-dione (NBQX). In vivo, differentiated oligodendrocytes in subcortical white matter expressed AMPA receptors and were selectively injured by microstereotaxic injection of AMPA but not NMDA. These data suggest that oligodendrocytes share with neurons a high vulnerability to AMPA/kainate receptor-mediated death, a mechanism that may contribute to white matter injury in CNS disease.

Mixed (neutrophil-rich) interstitial pneumonitis in biopsy specimens of lung allografts: a clinicopathologic evaluation

STUDY OBJECTIVES

Mixed interstitial pneumonitis (MIP), defined herein as a diffuse neutrophil-rich inflammatory infiltrate within the interstitial tissues, is an uncommon finding that is not a standard manifestation of acute or chronic rejection. This study examines the clinical significance of MIP in lung allograft recipients at St. Louis University Hospital.

DESIGN

We retrospectively reviewed surgical pathology reports from a selected 50-month period, and identified MIP reported in 13 transbronchial biopsy specimens in lung transplant recipients, representing 4.7% of all lung allograft biopsy specimens seen during this 4-year period. Biopsy specimens with MIP were examined to confirm the presence of a neutrophil-rich interstitial infiltrate and other associated histopathologic findings. The culture results, cytopathologic findings, and clinical charts of the affected patients were also reviewed.

MEASUREMENTS AND RESULTS

The detection of MIP at some point in a patient's posttransplant course was found to be associated with a significantly shorter (p < 0.01) survival, when compared to lung allograft recipients who did not show this finding. A total of seven lung allograft recipients (23% of total) showed MIP at some point in their posttransplant course. Four of the seven (57%) were actively smoking following lung transplantation, compared to 0 of 22 patients who did not show MIP. Six of the 13 MIP biopsy specimens were associated with positive cultures. In no case did MIP coexist with the conventional histologic patterns of acute or chronic rejection. MIP also did not correlate with levels of immunosuppressive therapy or with the incidence of rejection at other times in the patients' posttransplant courses.

CONCLUSIONS

We found no evidence that MIP represents an unusual form of acute or chronic rejection. Instead, it appears to represent a response to acute injury, similar to other injury patterns (hyaline membranes, organizing pneumonia) in transplant recipients. Exposure to tobacco smoke is likely to have played a role in the development of MIP in at least some cases. Because patients with MIP had a significantly shorter posttransplant survival, MIP may usefully identify lung allograft recipients at risk for an adverse outcome.

Incidental early detection of a splenic marginal zone lymphoma by polymerase chain reaction analysis of paraffin-embedded tissue

Splenic marginal zone lymphoma (SMZL) most commonly presents with splenomegaly and stage IV disease. To our knowledge, there have been only two reported cases of SMZL without associated splenomegaly; one was detected incidentally after a bicycle accident. This previously reported case represented an early-stage SMZL with monoclonality confirmed by immunohistochemistry. We report a case of early-stage SMZL detected incidentally following a motor vehicle accident; monoclonality was confirmed by polymerase chain reaction analysis of paraffin-embedded tissue owing to the inability of confirmation by immunohistochemical techniques. We describe our findings and emphasize the importance of recognizing early stages of SMZL in incidental splenectomies by polymerase chain reaction analysis of paraffin-embedded tissue. Frozen tissue is not generally available in such cases.

Intravenous cyclosporine for severe attacks of ulcerative colitis: a survey of Canadian gastroenterologists

A single randomized trial evaluated the use of intravenous cyclosporine treatment for severe attacks of ulcerative colitis. The perceived efficacy and safety of this intervention were measured through a survey of the membership of the Canadian Association of Gastroenterology (CAG).

METHODS

All CAG members were mailed a survey with questions regarding their familiarity with the data supporting the use of cyclosporine, their perception of the efficacy and toxicity of the drug, and whether patients who fail conventional treatment should receive this therapy. The proportion of respondents who had used cyclosporine to treat severe ulcerative colitis was determined.

RESULTS

One hundred and sixty-one responses were received (34% response rate). Sixty-four per cent of respondents were academic faculty members and 82% treated patients with severe colitis. Using multivariate analyses, positive associations were found between the respondents' age (P = 0.004) and subspecialty training in gastroenterology (P = 0.001), and whether respondents treat patients with severe ulcerative colitis. Twenty-six per cent of individuals had prescribed cyclosporine for this indication, of whom 88% were in academic practice (P = 0.007). Over 90% of respondents believe that further clinical trials are needed before cyclosporine becomes accepted as standard therapy.

CONCLUSIONS

Although the use of cyclosporine is measurable among Canadian gastroenterologists, the majority believe that further clinical trials are necessary before the drug is accepted as a standard therapy.

Neuronal and glial apoptosis after traumatic spinal cord injury

Cell death was examined by studying the spinal cords of rats subjected to traumatic insults of mild to moderate severity. Within minutes after mild weight drop impact (a 10 gm weight falling 6.25 mm), neurons in the immediate impact area showed a loss of cytoplasmic Nissl substances. Over the next 7 d, this lesion area expanded and cavitated. Terminal deoxynucleotidyl transferase (TdT)-mediated deoxyuridine triphosphate-biotin nick end labeling (TUNEL)-positive neurons were noted primarily restricted to the gross lesion area 4-24 hr after injury, with a maximum presence at 8 hr after injury. TUNEL-positive glia were present at all stages studied between 4 hr and 14 d, with a maximum presence within the lesion area 24 hr after injury. However 7 d after injury, a second wave of TUNEL-positive glial cells was noted in the white matter peripheral to the lesion and extending at least several millimeters away from the lesion center. The suggestion of apoptosis was supported by electron microscopy, as well as by nuclear staining with Hoechst 33342 dye, and by examination of DNA prepared from the lesion site. Furthermore, repeated intraperitoneal injections of cycloheximide, beginning immediately after a 12.5 mm weight drop insult, produced a substantial reduction in histological evidence of cord damage and in motor dysfunction assessed 4 weeks later. Present data support the hypothesis that apoptosis dependent on active protein synthesis contributes to the neuronal and glial cell death, as well as to the neurological dysfunction, induced by mild-to-moderate severity traumatic insults to the rat spinal cord.

Susceptibility to apoptosis is enhanced in immature cortical neurons

The susceptibility of cortical neurons to two forms of apoptotic death was compared with susceptibility to excitotoxic death during development in vitro (DIV 4-21). Murine cortical cultures were exposed for 48 h to the phosphatase inhibitor cyclosporine, the protein kinase inhibitor staurosporine or the excitotoxin N-methyl-D-aspartate (NMDA). Susceptibility to apoptosis induced by staurosporine or cyclosporine was maximal between DIV 4-10 and declined from DIV 10 through 18. The opposite pattern was observed with susceptibility to NMDA receptor-mediated excitotoxic necrosis, which was minimal at DIV 6 and progressively increased through DIV 21.

Histopathologic diagnosis made in lung tissue resected from patients with severe emphysema undergoing lung volume reduction surgery

STUDY OBJECTIVES

This study reports histopathologic findings in a group of emphysema patients who underwent thoracoscopic lung volume reduction surgery (75) or sternotomy (five) with the purpose to induce functional improvement and relief of dyspnea. Immediate outcome and complications were correlated to histologic patterns.

DESIGN

Histopathologic material obtained in lung volume reduction surgery in 80 consecutive patients was analyzed. Thirty patients who had other histopathologic diagnoses in addition to emphysema were grouped and compared with 50 patients found to have emphysema exclusively. Postoperative outcome and preoperative lung function variables were compared.

MEASUREMENTS AND RESULTS

All patients had severe obstructive lung disease and significant air trapping preoperatively documented by pulmonary function testing. All had severe exertional dyspnea. All had chest radiographs, CT, and nuclear medicine lung scans consistent only with emphysema. All portions of resected lung tissue were weighed, lung volume was estimated, and routine histopathologic studies were made. Thirty patients (37.5%) had unsuspected findings such as interstitial fibrosis, noncaseating granulomatosis, chronic inflammation, and unsuspected neoplasia (three carcinomas, one carcinoid). Retrospective review of imaging studies in these patients failed to show infiltrative processes. The average lung weight resected in this group was significantly heavier (65+/-18 g) compared with the other group (56+/-13 g), although both had the same estimated lung volume. Average number of days requiring chest tubes and length of hospitalization was also significantly higher (12.8+/-19 vs 6.4+/-5 days with chest tubes and 17.4+/-22 vs 8.5+/-6 days of hospitalization, respectively). None of the preoperative pulmonary function tests variables were different between the two groups. Serious postoperative complications were more frequent in these patients compared with those who showed only emphysema.

CONCLUSIONS

A significant portion of patients diagnosed as having severe emphysema will have other unsuspected histologic findings. When subjected to lung volume reduction surgery, this subgroup will have more serious complications and longer periods of air leaks, requiring longer hospitalization time. Retrospective review of imaging studies and preoperative pulmonary function tests used to select patients for lung volume reduction failed to identify this subgroup.