Changes in Cognitive Function After Kidney Transplantation: A Longitudinal Cohort Study

RATIONALE & OBJECTIVE

Kidney disease negatively affects cognition. We assessed the effect of kidney transplantation (KT) on different cognitive domains.

STUDY DESIGN

Prospective cohort study.

SETTING & PARTICIPANTS

We examined pre- versus post-KT cognition in patients waitlisted for KT at an academic center.

PREDICTORS

Transplant status. We measured cognitive function before KT (n=101), 3 months after KT (n=78), and 1 year after KT (n = 83).

OUTCOMES

Our primary outcome was change in cognitive function before versus after KT. We used standard neuropsychological tests to assess global cognition (Mini-Mental State Exam [MMSE]), episodic/declarative memory (Logical Memory), psychomotor speed/visuospatial function (Digit Symbol Substitution Test [DSST], Trail Making Test [TMT] A), working memory/attention (Digit Span), executive function (TMT B), and semantic memory/verbal fluency/language (Category Fluency).

ANALYTICAL APPROACH

Using linear mixed model analysis, we evaluated the changes in neuropsychological test scores adjusted for age, sex, race, education, and number of assessments.

RESULTS

Before KT, Logical Memory I and II, DSST, MMSE, Category Fluency (animal naming), and Digit Span backward scores were low compared with normative values from the National Alzheimer's Coordinating Center data. Logical Memory I and II scores improved after KT (pre- vs post-KT, estimated group difference [d]=3.3, P<0.001 for Logical Memory I; d=4.27, P<0.001 for Logical Memory II), such that post-KT scores were similar to normative values (post-KT vs normative values, d = -0.37, P=0.06 for Logical Memory I; d = -0.89, P=0.08 for Logical Memory II). Category Fluency (animal naming; d=2.4, P<0.001) and DSST (d=3.12, P=0.01) scores also improved with KT, but post-KT DSST scores remained lower than normative values (post-KT vs normative values, d = -5.17, P<0.001). MMSE, Digit Span, and TMT A and B scores did not change after KT.

LIMITATIONS

Single-center study.

CONCLUSIONS

Episodic and verbal declarative memory normalize after KT. Semantic memory, verbal fluency, language, psychomotor speed, and visuospatial function show partial improvement. Cognitive impairment in kidney disease is therefore at least partly reversible with KT.

PLAIN-LANGUAGE SUMMARY

Cognitive impairment in kidney disease affects self-esteem, vocational abilities, quality of life, health care costs, and mortality. It is not clear whether kidney transplantation (KT) improves cognition and whether the improvement is uniform across cognitive domains. The distinction between reversible and irreversible cognitive impairment has important implications in the clinical care of patients before and after KT. We assessed cognition before KT and 3 months and 12 months after KT and discovered that episodic and verbal declarative memory normalized with KT. Semantic memory, verbal fluency, language, psychomotor speed, and visuospatial function also improved with KT but did not reach normal levels. Cognitive impairment in kidney disease is therefore at least partly reversible.

Contaminated Airway Task Training: How to Adapt an Existing Airway Manikin Head for Active Airway Soiling

The massively contaminated airway is an important and often daunting entity for airway providers. Although massively contaminated airways are considered high acuity, low-occurrence presentations in emergency medicine and pre-hospital settings, formal training in the management of contaminated airways is heterogeneous and infrequent. To facilitate training and augment simulation, an airway task trainer is critical. To our knowledge, this is the first readily accessible, peer-reviewed, detailed technical report to build a low-cost, high-fidelity, contaminated airway task trainer. This trainer can be seamlessly integrated into simulated resuscitation scenarios and/or airway training workshops, reinforcing skill acquisition and retention for the management of the massively contaminated airway.

A - 184 Validity of the Infrequent Patterns of Performance Embedded Performance Validity Indicators in a Mixed Clinical Sample

OBJECTIVE

Novel performance validity tests (PVTs) for the Hopkins Verbal Learning Test-Revised (HVLT-R) and Brief Visuospatial Memory Test-Revised (BVMT-R), derived from infrequent patterns of performance (IPOP), were developed to examine invalid memory performance while reducing false positive misclassification. To examine their classification accuracy, these indicators were compared to several existing embedded PVTs in a mixed clinical sample.

METHOD

A chart review was completed for 75 adult outpatients (Mean Age = 52, Range = 19-85) referred to an academic medical center outpatient clinic for neuropsychological evaluation. Twenty-eight percent of the sample failed the Medical Symptom Validity Test (MSVT), which was used as the criterion to indicate invalid performance. Several established embedded validity indicators were calculated from HVLT-R and BVMT-R scores, including the recognition discrimination index (RDI) and percent retention (PR), as well as the Reliable Digit Span (RDS) validity indicator. Classification statistics, including sensitivity, specific, likelihood ratios, predictive values, and overall accuracy, were calculated and compared.

RESULTS

The HVLT-R IPOP had a higher overall classification accuracy (72%) compared to the RDI indicator (68%) while maintaining excellent specificity (97%). The BVMT-R IPOP had identical classification accuracy (75%) compared to the RDI and PR indicators with very high specificity (96%). Both indicators were more accurate than RDS (72%).

CONCLUSIONS

The HVLT-R and BVMT-R IPOP performance validity indicators produced adequate classification statistics when compared to existing embedded PVTs. Both indicators maintained excellent specificity, which is crucial in reducing false positive classification. Future research will focus on further examining the validity of these indicators in other clinical groups and known groups, including medico-legal populations.

A - 182 Comparison of the Short Test of Mental Status to Traditional Neuropsychological Tests

OBJECTIVE

The Short Test of Mental Status (STMS) was developed by Kokmen and colleagues as a brief cognitive screening test. Existing research has found the STMS to be sensitive in detecting cognitive impairment in patients with Mild Cognitive Impairment (MCI). The STMS has also been shown to be comparable to other cognitive screening instruments, including the Montreal Cognitive Assessment (MoCA). However, the relationship between the STMS and traditional neuropsychological tests has yet to be evaluated. This study sought to explore the concordance between the STMS test items and neuropsychological test variables in a mixed clinical sample.

METHOD

Neuropsychological test data was collected from an archival database for 150 adults (Mean age = 71.4 years) referred to an interdisciplinary dementia care clinic at an academic medical center. Descriptive statistics for the demographic and test variables were produced. Pearson correlations were used to examine the relationships between the STMS total score, STMS item scores, and the neuropsychological test variables.

RESULTS

Statistically significant correlations were found between the STMS item scores and their corresponding neuropsychological tests: Orientation (r = 0.46-0.56), Attention (r = 0.39-0.51), Registration-Trials (r = 0.32-0.50), Calculations (r = 0.30-0.41), Construction (r = 0.43), Information (r = 0.56), and Recall (r = 0.61-0.71). The STMS total score was significantly correlated with all neuropsychological test scores (r = 0.30-72).

CONCLUSIONS

The STMS shows strong concordance with traditional neuropsychological tests in a dementia clinic sample. Future analyses will include examining construct validity of the STMS with different clinical groups and diagnoses as well as an exploration of the underlying factor structure of the STMS.

A - 183 Novel Performance Validity Indicators for Frequently Used Memory Tests Using Infrequent Patterns of Memory Performance

OBJECTIVE

Determining performance validity is an imperative part of neuropsychological assessment in concussion management. Several existing embedded performance validity tests (PVTs) have been developed for popular measures of memory, Hopkins Verbal Learning Test Revised (HVLT-R) and Brief Visuospatial Memory Test Revised (BVMT-R). However, many PVTs utilize cognitive performance measures to classify performance invalidity, which increases the likelihood of false positives, especially in clinical populations. To reduce this possibility, a novel embedded PVT was developed utilizing infrequent patterns of performance in a primarily amnestic, dementia population.

METHOD

Neuropsychological data for 50 adult outpatients (Mean Age = 73, Range = 50-97) who met criteria for Major Neurocognitive Disorder (MND) were reviewed. Infrequent patterns of performance (IPOP) were identified on the HVLT-R and BVMT-R, including inconsistency between recall and recognition, unusually high intrusions, exceedingly poor learning, and lack of primary effect. Scaled scores were developed from the IPOP scores (0 = 0-74%, 1 = 75-94%, 2 = 95-99%). Total IPOP scaled scores were compared to existing embedded PVTs, which utilized recognition discrimination and percent retention scores, to examine classification rates.

RESULTS

Failure rates on the embedded PVTs for the HVLT-R were 16-42% and BVMT-R 38-58% whereas elevated IPOP scaled scores were identified in less than 15% of the sample.

CONCLUSIONS

High frequencies of embedded PVT failures were found in a clinical sample of patients with MND, which is concerning for false positive misclassification. Infrequent patterns of memory performances identified in a dementia population were less frequent and could potentially be utilized to examine performance validity in persons suspected of producing invalid memory performances.

Demographically-adjusted normative data among Latinos for the version 3 of the Alzheimer's Disease Centers' Neuropsychological Test Battery in the Uniform Data Set

INTRODUCTION

We developed demographically-adjusted normative data for Spanish- and English-speaking Latinos on the Version 3.0 of the National Alzheimer's Coordinating Center Uniform Data Set Neuropsychological Battery (UDS3-NB).

METHODS

Healthy Latino adults (N = 437) age 50-94 (191 Spanish- and 246 English-speaking) enrolled in Alzheimer's Disease Research Centers completed the UDS3-NB in their preferred language. Normative data were developed via multiple linear regression models on UDS3-NB raw scores stratified by language group with terms for demographic characteristics (age, years of formal education, and sex).

RESULTS

Younger age and more years of education were associated with better performance on most tests in both language groups, with education being particularly influential on raw scores among Spanish-speakers. Sex effects varied across tests and language groups.

DISCUSSION

These normative data are a crucial step toward improving diagnostic accuracy of the UDS3-NB for neurocognitive disorders among Latinos in the United States and addressing disparities in Alzheimer's disease and related dementias.

HIGHLIGHTS

We developed normative data on the UDS3-NB for Latinos in the US ages 50-94. Younger age and more years of education were linked to better raw scores in several cognitive tests. Education was particularly influential on raw scores among Spanish-speakers. Sex effects varied across tests and between English- and Spanish-speaking Latinos. These normative data might improve diagnostic accuracy of the UDS3-NB among Latinos.

Influence of Baseline Diastolic Blood Pressure on the Effects of Systolic Blood Pressure Lowering on Cognitive Function in Type 2 Diabetes Mellitus

BACKGROUND

Lowering of systolic blood pressure (SBP) in patients with low diastolic blood pressure (DBP), can further lower DBP. This can potentially decrease cerebral perfusion and cognition. We examined the influence of baseline DBP on the effect of lowering SBP on cognition.

METHODS

This is a post hoc analysis of the Memory in Diabetes (MIND) substudy (N = 1,430) of the Action to Control Cardiovascular Risk in Diabetes (ACCORD) study (NCT00000620). Standard neuropsychological tests (Digit Symbol Substitution Test [DSST], Mini-Mental State Examination [MMSE], Rey Auditory Verbal Learning Test [RAVLT], and Stroop test) were performed at baseline and months 20 and 40. We compared the effects of intensive (goal SBP <120 mm Hg) vs. standard (goal SBP <140 mm Hg) SBP control on the changes in the 4 test scores from baseline to the averages of months 20 and 40 across the range of baseline DBP using cubic spline terms.

RESULTS

Mean age was 63 ± 6 years, 55% were women and 66% White. Participates with lower baseline DBP were older, had more cardiovascular events and a longer duration of diabetes. There was no difference in the change in DSST (-0.22; 95% CI -0.97, 0.52), MMSE (-0.14; 95% CI -0.34, 0.06), RAVLT (-0.12; 95% CI -0.29, 0.06), and Stroop interference (-0.47; 95% CI -1.76, 0.82) in the intensive vs. standard SBP intervention. There was no interaction between baseline DBP and change in scores with the SBP intervention.

CONCLUSIONS

Intensive SBP reduction does not adversely affect cognition, even in those with low baseline DBP.

AIM™ platform: A new immunotherapy approach for viral diseases

In addition to complications of acute diseases, chronic viral infections are linked to both malignancies and autoimmune disorders. Lack of adequate treatment options for Epstein-Barr virus (EBV), Human T-lymphotropic virus type 1 (HTLV-1), and human papillomavirus (HPV) remains. The NexImmune Artificial Immune Modulation (AIM) nanoparticle platform can be used to direct T cell responses by mimicking the dendritic cell function. In one application, AIM nanoparticles are used ex vivo to enrich and expand (E+E) rare populations of multi-antigen-specific CD8⁺ T cells for use of these cells as an AIM adoptive cell therapy. This study has demonstrated using E+E CD8⁺ T cells, the functional relevance of targeting EBV, HTLV-1, and HPV. Expanded T cells consist primarily of effector memory, central memory, and self-renewing stem-like memory T cells directed at selected viral antigen peptides presented by the AIM nanoparticle. T cells expanded against either EBV- or HPV-antigens were highly polyfunctional and displayed substantial in vitro cytotoxic activity against cell lines expressing the respective antigens. Our initial work was in the context of exploring T cells expanded from healthy donors and restricted to human leukocyte antigen (HLA)-A*02:01 serotype. AIM Adoptive Cell Therapies (ACT) are also being developed for other HLA class I serotypes. AIM adoptive cell therapies of autologous or allogeneic T cells specific to antigens associated with acute myeloid leukemia and multiple myeloma are currently in the clinic. The utility and flexibility of the AIM nanoparticle platform will be expanded as we advance the second application, an AIM injectable off-the-shelf nanoparticle, which targets multiple antigen-specific T cell populations to either activate, tolerize, or destroy these targeted CD8⁺ T cells directly in vivo, leaving non-target cells alone. The AIM injectable platform offers the potential to develop new multi-antigen specific therapies for treating infectious diseases, cancer, and autoimmune diseases.

Barriers and enablers that influence guideline-based care of geriatric fall patients presenting to the emergency department

BACKGROUND

Geriatric patients commonly present to the ED after a fall. Recent evidence suggests that ED physicians are poorly adherent to published ED-specific geriatric fall guidelines. This study applied a theoretical domains framework (TDF) approach to systematically investigate barriers and enablers in the provision of guideline-based care to ED geriatric fall patients.

METHODS

From June to September 2017, semistructured interviews of staff ED physicians practising in Ontario, Canada, were conducted and analysed. An interview guide based on the TDF was used to capture 14 domains influencing provision of guideline-based care. Relevant domains were identified based on frequencies of beliefs, existence of conflicting beliefs and evidence of strong beliefs that would influence provision of guideline-based care.

RESULTS

Eleven interviews were conducted with practising ED physicians. Thirty belief statements were identified across 13 relevant TDF domains (all except Optimism). Prominent themes included lack of knowledge, paucity of evidence, heterogeneous self-perceived skills, perceived increased time and workload, importance of allied health support, inconsistently available allied health workers, lack of positive reinforcement, emotions negatively impacting these clinical encounters and support for memory aids. Overall, ED physicians were supportive of guideline implementation, and believe it will lead to better outcomes for geriatric fall patients.

CONCLUSION

This study identified important barriers and enablers to provision of guideline-based care in geriatric ED fall patients. Based on these findings, future implementation of guidelines nationally and internationally should focus on improving knowledge and training on guidelines, improving positive reinforcement for guideline-appropriate management, greater allied health support and further research to support guidelines.

Diffuse Lewy body disease manifesting as corticobasal syndrome: A rare form of Lewy body disease

OBJECTIVE

To describe clinical and pathologic characteristics of diffuse Lewy body disease (DLBD) manifesting as corticobasal syndrome (CBS).

METHODS

In 523 autopsy-confirmed cases of DLBD, we identified 11 patients diagnosed with CBS. For comparison, we studied 22 DLBD brains with antemortem presentation of dementia with Lewy bodies (DLB). Given previous studies suggesting the importance of pathology in peri-Rolandic cortices in CBS, we used digital pathology to count Lewy bodies and to quantify intracytoplasmic and neuritic α-synuclein and phospho-tau burden in the motor cortex.

RESULTS

DLBD patients with antemortem features of CBS were significantly younger at disease onset and less likely to have REM sleep behavior disorder than DLBD cases who met clinical criteria for DLB during life. Patients with DLBD manifesting as CBS had more Lewy bodies in the motor cortex than DLBD manifesting as clinically probable DLB. Three cases had concomitant progressive supranuclear palsy and 4 cases had concomitant Alzheimer disease as probable correlates of CBS.

CONCLUSION

The neuropathology underlying CBS is heterogeneous, including corticobasal degeneration, Alzheimer disease, and progressive supranuclear palsy. This study suggests that atypical variants of Lewy body disease with severe peri-Rolandic Lewy-related pathology can present clinically as CBS. Patients with DLBD who present as CBS tend to have an earlier age at onset and are less likely to have clinical features of DLB, such as dream enactment behavior during sleep, visual hallucinations, and levodopa-responsive parkinsonism. Future studies with biofluid or molecular imaging biomarkers for α-synuclein will permit better recognition of this uncommon pathologic substrate of CBS.

Cognitive impairment in progressive supranuclear palsy is associated with tau burden

BACKGROUND

Cognitive impairment is one of the core features of progressive supranuclear palsy. This study aimed to clarify the profile of cognitive impairment and its underlying pathology in progressive supranuclear palsy.

METHODS

We retrospectively reviewed medical records to evaluate the pattern and severity of cognitive impairment in 121 autopsy-confirmed progressive supranuclear palsy patients. A subset of 37 patients underwent neuropsychological evaluation as part of their clinical workup. The burden of progressive supranuclear palsy-related tau pathology (neurofibrillary tangles/pretangles, coiled bodies, tufted astrocytes, and threads) was semiquantitatively scored in 20 vulnerable brain regions. Concurrent pathologies potentially associated with cognitive impairment, such as Alzheimer's-type pathology, were also assessed. To evaluate possible genetic risk factors for cognitive impairment, genetic analysis for APOE and MAPT was performed.

RESULTS

Ninety patients (74%) had documented cognitive impairment based on neurologic evaluation. In a subgroup with neuropsychological testing (n = 37), executive functioning was the most severely impaired cognitive domain. A global cognitive impairment index (Spearman's rho, -0.49; P = 0.005) and executive functioning were negatively correlated with total tau burden (Spearman's rho, -0.51; P = 0.003), but not correlated with the Alzheimer's-type pathology. APOE ɛ4 carriers had more severe amyloid pathology, but total tau burden and a global cognitive impairment index did not differ from APOE ɛ4 noncarriers.

CONCLUSION

Cognitive impairment in progressive supranuclear palsy, most notably executive dysfunction, is associated with severity of progressive supranuclear palsy-related tau pathology. © 2017 International Parkinson and Movement Disorder Society.

tCRISPRi: tunable and reversible, one-step control of gene expression

The ability to control the level of gene expression is a major quest in biology. A widely used approach employs deletion of a nonessential gene of interest (knockout), or multi-step recombineering to move a gene of interest under a repressible promoter (knockdown). However, these genetic methods are laborious, and limited for quantitative study. Here, we report a tunable CRISPR-cas system, “tCRISPRi”, for precise and continuous titration of gene expression by more than 30-fold. Our tCRISPRi system employs various previous advancements into a single strain: (1) We constructed a new strain containing a tunable arabinose operon promoter P_BAD to quantitatively control the expression of CRISPR-(d)Cas protein over two orders of magnitude in a plasmid-free system. (2) tCRISPRi is reversible, and gene expression is repressed under knockdown conditions. (3) tCRISPRi shows significantly less than 10% leaky expression. (4) Most important from a practical perspective, construction of tCRISPRi to target a new gene requires only one-step of oligo recombineering. Our results show that tCRISPRi, in combination with recombineering, provides a simple and easy-to-implement tool for gene expression control, and is ideally suited for construction of both individual strains and high-throughput tunable knockdown libraries.

Profile of cognitive impairment and underlying pathology in multiple system atrophy

BACKGROUND

The objectives of this study were to elucidate any potential association between α-synuclein pathology and cognitive impairment and to determine the profile of cognitive impairment in multiple system atrophy (MSA) patients. To do this, we analyzed the clinical and pathologic features in autopsy-confirmed MSA patients.

METHODS

We retrospectively reviewed medical records, including neuropsychological test data, in 102 patients with autopsy-confirmed MSA in the Mayo Clinic brain bank. The burden of glial cytoplasmic inclusions and neuronal cytoplasmic inclusions were semiquantitatively scored in the limbic regions and middle frontal gyrus. We also assessed concurrent pathologies potentially causing dementia including Alzheimer's disease, hippocampal sclerosis, and cerebrovascular pathology.

RESULTS

Of 102 patients, 33 (32%) were documented to have cognitive impairment. Those that received objective testing, deficits primarily in processing speed and attention/executive functions were identified, which suggests a frontal-subcortical pattern of dysfunction. Of these 33 patients with cognitive impairment, 8 patients had concurrent pathologies of dementia. MSA patients with cognitive impairment had a greater burden of neuronal cytoplasmic inclusions in the dentate gyrus than patients without cognitive impairment, both including and excluding patients with concurrent pathologies of dementia.

CONCLUSIONS

The cognitive deficits observed in this study were more evident on neuropsychological assessment than with cognitive screens. Based on these findings, we recommend that clinicians consider more in-depth neuropsychological assessments if patients with MSA present with cognitive complaints. Although we did not identify the correlation between cognitive deficits and responsible neuroanatomical regions, a greater burden of neuronal cytoplasmic inclusions in the limbic regions was associated with cognitive impairment in MSA. © 2016 International Parkinson and Movement Disorder Society.

Bacteriophage cocktail significantly reduces Escherichia coli O157: H7 contamination of lettuce and beef, but does not protect against recontamination

Foods contaminated with Escherichia coli O157:H7 cause more than 63,000 foodborne illnesses in the United States every year, resulting in a significant economic impact on medical costs and product liabilities. Efforts to reduce contamination with E. coli O157:H7 have largely focused on washing, application of various antibacterial chemicals, and gamma-irradiation, each of which has practical and environmental drawbacks. A relatively recent, environmentally-friendly approach proposed for eliminating or significantly reducing E. coli O157:H7 contamination of foods is the use of lytic bacteriophages as biocontrol agents. We found that EcoShield™, a commercially available preparation composed of three lytic bacteriophages specific for E. coli O157:H7, significantly (p < 0.05) reduced the levels of the bacterium in experimentally contaminated beef by ≥ 94% and in lettuce by 87% after a five minute contact time. The reduced levels of bacteria were maintained for at least one week at refrigerated temperatures. However, the one-time application of EcoShield™ did not protect the foods from recontamination with E. coli O157:H7. Our results demonstrate that EcoShield™ is effective in significantly reducing contamination of beef and lettuce with E. coli O157:H7, but does not protect against potential later contamination due to, for example, unsanitary handling of the foods post processing.

A small group activity about bacterial regulation and complementation

As teachers, we well understand the need for activities that help develop critical-thinking skills in microbiology. In our experience, one concept that students have difficulty understanding is transcriptional regulation of bacterial genes. To help with this, we developed and evaluated a paper-based activity to help students understand and apply the concepts of bacterial transcriptional regulation. While we don't identify it as such, we use a complementation experiment to assess student understanding of how regulation changes when new DNA is introduced. In Part 1 of this activity, students complete an open-book, take-home assignment that asks them to define common terminology related to regulation, and draw the regulatory components of different scenarios involving positive and negative regulation. In Part 2, students work in small groups of 3-4 to depict the regulatory components for a different scenario. They are asked to explain the results of a complementation experiment based on this scenario. They then predict the results of a slightly different experiment. Students who completed the Regulation Activity did significantly better on post-test questions related to regulation, compared to pre-test questions.

Effects of diet on rumen proliferation and fecal shedding of Escherichia coil O157:H7 in calves

Calves inoculated with Escherichia coli O157:H7 and fed either a high-roughage or high-concentrate diet were evaluated for rumen proliferation and fecal shedding of E. coli O157:H7. Calves fed the high-roughage diet had lower mean rumen volatile fatty acid concentrations and higher rumen pH values than did calves fed the high-concentrate diet. Despite these differences in rumen conditions, the calves fed the high-roughage diet did not have greater rumen populations of E. coli O157: H7 and did not exhibit increased or longer fecal shedding compared with the calves fed the high-concentrate diet. Two calves shedding the highest mean concentrations of E. coli O157:H7 were both fed the high-concentrate diet. There was a significant (P < 0.05) positive correlation between fecal shedding and rumen volatile fatty acid concentration in calves fed a high-concentrate diet. The effects of diet on E. coli O157:H7 proliferation and acid resistance were investigated using an in vitro rumen fermentation system. Rumen fluid collected from steers fed a high-roughage diet, but not from steers fed a high-concentrate diet, supported the proliferation of E. coli O157:H7. Rumen fluid from steers fed a high-concentrate diet rapidly induced acid resistance in E. coli O157:H7. The impact of diet on fecal shedding of E. coli O157:H7 is still unclear and may depend on dietary effects on fermentation in the colon and on diet-induced changes in the resident microflora. However, rapid development of acid tolerance by E. coli O157:H7 in the rumens of calves fed high-concentrate diets, allowing larger populations to survive passage through the acidic abomasum to proliferate in the colon, may be one factor that influences fecal shedding in cattle on feed.

Fecal shedding and rumen growth of Escherichia coli O157:H7 in fasted calves

Nine weaned calves aged from 8 to 12 weeks were fitted with rumen cannulas and were inoculated by cannula with 10(10) CFU of a five-strain mixture of nalidixic acid-resistant Escherichia coli O157:H7. Six calves were fasted for 48 h on days 15 and 16 and days 22 and 23 after inoculation. Samples of rumen contents and feces were obtained daily to enumerate E. coli O157:H7 populations and to determine rumen volatile fatty acid (VFA) concentrations and rumen pH. Fasting resulted in a marked decrease in rumen VFA concentrations from a mean of 135 mmol/liter before the fast to a mean of 35 mmol/liter during the second day of the fast. However, there was no correlation between daily VFA concentration and daily rumen or fecal numbers of E. coli O157:H7 in any of the calves. Fasting generally had no significant effect on the rumen or fecal numbers of E. coli O157:H7. The exception was a single fasted calf that experienced a 3-log(10) CFU/g increase in fecal shedding during and after the first fast. Despite the consistent changes in VFA concentrations in fasted calves, the fluctuations in rumen numbers of E. coli O157:H7 in the rumen of fasted calves were minimal. At the end of the experiment, E. coli O157:H7 was detected in either the rumen or omasum in two of three control calves at necropsy and in either the rumen or reticulum in five of six fasted calves. E. coli O157:H7 was detected in the colon in two of three control calves and in six of six fasted calves at necropsy. These results suggest that in cattle already shedding E. coli O157:H7, feed withdrawal and the associated changes in rumen pH and VFA concentrations have little effect on fecal shedding and rumen proliferation of E. coli O157:H7.

Surgical treatment of subchondral cyst-like lesions in the tibia of an adult pony

A 13 year-old pony was evaluated because of right hind limb lameness of acute onset. Radiographs of the right tarsus obtained shortly after the onset of lameness were normal, but results of nuclear scintigraphy were abnormal. Two radiolucent subchondral cyst-like lesions of the distal part of the tibia were seen on radiographs obtained 9 months later. The lesions were surgically decompressed, and the pony was sound 1 year later. It is hypothesized that a traumatic insult created a crack or split in the articular cartilage that allowed subsequent development of the cyst-like lesions.

Case-mix groups for VA hospital-based home care

The purpose of this study is to group hospital-based home care (HBHC) patients homogeneously by their characteristics with respect to cost of care to develop alternative case mix methods for management and reimbursement (allocation) purposes. Six Veterans Affairs (VA) HBHC programs in Fiscal Year (FY) 1986 that maximized patient, program, and regional variation were selected, all of which agreed to participate. All HBHC patients active in each program on October 1, 1987, in addition to all new admissions through September 30, 1988 (FY88), comprised the sample of 874 unique patients. Statistical methods include the use of classification and regression trees (CART software: Statistical Software; Lafayette, CA), analysis of variance, and multiple linear regression techniques. The resulting algorithm is a three-factor model that explains 20% of the cost variance (R2 = 20%, with a cross validation R2 of 12%). Similar classifications such as the RUG-II, which is utilized for VA nursing home and intermediate care, the VA outpatient resource allocation model, and the RUG-HHC, utilized in some states for reimbursing home health care in the private sector, explained less of the cost variance and, therefore, are less adequate for VA home care resource allocation.

Buspirone treatment of aggression and anxiety in mentally retarded patients: a multiple-baseline, placebo lead-in study

Buspirone, a new anxiolytic agent, was used in a multiple-baseline, placebo lead-in study for the treatment of aggression and anxiety in six mentally retarded adult patients. The findings demonstrate buspirone's effectiveness in reducing aggression and anxiety in a mentally retarded group of subjects without causing deleterious cognitive side effects. The authors review a body of literature on animal and human subjects where buspirone was used in the treatment of aggression and other mental disorders. Unlike neuroleptics and benzodiazepines, buspirone does not cause sedation which can compromise adaptive and intellectual capacities and thus reduce the patient's potential to benefit from training programs.

Autosomal dominant keratoderma, ichthyosiform dermatosis and elevated serum beta-glucuronidase

Five patients in a large pedigree with autosomal dominant palmoplantar keratoderma and/or an ichthyosiform dermatosis were studied. Biopsies of the keratoderma, a remote hyperkeratotic plaque on an arm and the ichthyosis all revealed the same histopathologic changes including hyperkeratosis with round retained nuclei. All 5 patients had elevated serum beta-glucuronidase activity. The significance of beta-glucuronidase in this and other skin diseases is discussed.

The pharmacokinetics of loratadine in normal geriatric volunteers

The pharmacokinetics of loratadine, a non-sedating anti-histamine, were studied in 12 normal geriatric volunteers. In an open label fashion, each volunteer received one 40 mg loratadine capsule. Blood was collected prior to and at specified times (up to 120 h) after dosing. Plasma loratadine concentrations were determined by a specific radioimmunoassay and those of an active metabolite, descarboethoxyloratadine, by high performance liquid chromatography. Concentrations of loratadine in the disposition phase were fitted to a biexponential equation and those of descarboethoxyloratadine to either a monoexponential or biexponential equation for pharmacokinetic analysis. Loratadine was rapidly absorbed, reaching a maximum plasma concentration of 50.5 ng/ml at 1.5 h after dosing. The disposition half-lives of loratadine in the distribution and elimination phases were 1.5 and 18.2 h, respectively. The area under the plasma concentration-time curve, was 146.7 h.ng/ml. Descarboethoxyloratadine had a maximum plasma concentration of 28.0 ng/ml at 2.9 h post-dose and an area under the concentration-time curve of 394.9 h.ng/ml. Its disposition half-lives in the distribution and elimination phases were 2.8 and 17.4 h, respectively. Comparison of these data with those from a previous study of loratadine in young adults showed no clear differences in the disposition half-lives between the two groups. The clearance of loratadine tends to be lower in the elderly, but inter-individual variation within each age group appears greater than any age effect.

Coxofemoral luxation in two foals wearing hindlimb casts

Two foals wearing hindlimb casts developed coxofemoral luxations 6 days and 9 days after the casts were applied. One foal had a cast on one hindlimb up to the proximal portion of the tibia and the other foal had tube casts on all 4 limbs. Although the incidents that resulted in the luxations were not observed, they probably occurred during awkward attempts to stand or from being pushed by the mare, with the affected limb being caught under the body in a forward extended and adducted position.

Aquagenic angioedema

A 21-year-old man experienced persistent swelling of his lips and generalized pruritus without hives associated with swimming. Provocative testing with tap water produced transient edema and pruritus. Sweating and methacholine testing did not produce cholinergic urticaria. After several weeks, the angioedema gradually subsided, the reaction to tap water became negative, and the patient was able to swim again without reactions. Water should be added to the list of physical agents that cause angioedema as well as urticaria.

Type II renal tubular acidosis in a mare

Persistent, severe metabolic acidosis complicated the operative and postoperative period in a 4-year-old mare with colic. On the basis of clinical and laboratory findings, a renal tubular disorder was diagnosed. Renal tubular acidosis is rare in horses. In the only report found on the subject, type I renal tubular acidosis was described in 2 horses. Bicarbonate titration studies in our case helped document type II renal tubular acidosis in this mare.

Perianal Paget's disease

Paget's disease involves the ducts of apocrine glands and the overlying epidermis and is considered to be locally neoplastic. It is capable of developing into invasive carcinoma and in this event the prognosis is poor. The perianal skin may be affected by Paget's disease. This is a rare disorder and the four patients who have been seen with this disease at St Mark's Hospital since 1930 are described.