Acceptability of an intravaginal ring for simultaneously preventing HIV infection and pregnancy: Qualitative findings of the Kisumu Combined Ring Study, 2019

Multipurpose prevention technology intravaginal rings (MPT IVRs) may offer a promising solution for addressing women's multiple sexual and reproductive health needs. We describe MPT IVR acceptability perspectives and examine user experiences of 25 cisgender women aged 18-34 years enrolled in a phase IIa randomized, partially blinded, placebo-controlled evaluation of tenofovir-based IVRs with and without contraceptive co-formulation. All took part in an individual, audio-recorded, semi-structured qualitative interview. A thematic analysis of transcribed interviews was completed in MaxQDA. Participants shared little to no knowledge of or experience with IVRs prior to joining the study. Four MPT IVR themes were identified: physical well-being, method reliability, personal management, and societal endorsement. Commonly cited of concern, but less described as being experienced, were physical discomforts (e.g., painful insertion/removal; inability to carry out daily activities/chores; foreign body sensation; expulsion; sexual interference, or debilitating side effects). Uncertainty regarding efficacy influenced perspectives about intended prevention benefits. Personal choices in managing reproduction and sexual behaviors had to be congruent with sociocultural values and norms for acceptance beyond the individual user level. Participants viewed broader community acceptance as likely to be mixed given community opposition to the use of modern family planning methods. They also shared concerns that IVR use could lead to infertility, especially among nulliparous women, or that it would encourage premarital sex or high-risk sexual behaviors among adolescent and young women. While a MPT IVR may not be suitable for all women, first-hand testimonials could help influence collective receptivity. Additional community acceptability research is needed. Clinical Trial Registration The study is registered at http://ClinicalTrials.gov under the identifier NCT03762382.

Abstract P1-02-10: Breast tumor measurement after neoadjuvant chemotherapy using the 8th edition of the American Joint Committee on cancer staging system: Impact on estimates of tumor size and discrepancies with residual cancer burden class

Background: In the 8th Edition of the American Joint Committee on Cancer Staging System (yAJCC) for breast cancer after neoadjuvant chemotherapy (NAC), tumor size is based on the largest focus of residual tumor, excluding treatment-related fibrosis. The goal of this study was to assess the impact of strict adherence to yAJCC criteria on residual breast tumor size and discrepancies between yAJCC stage and Residual Cancer Burden (RCB) class. Design: Breast cancer resections after NAC from 2016-2020 were identified in the Anatomic Pathology laboratory information system. Stage IV, pT4b, pT4d, pCR, neoadjuvant endocrine therapy alone and no response to NAC were exclusion criteria. Tumor size, ypT category and focality were reassessed using current yAJCC criteria and compared to the original reports. A median of 29 slides per case were reviewed (range, 9-113). Results: A total of 189 cases met inclusion criteria, including 58 (31%) TNBCs, 50 (26%) HER2+ and 81 (43%) hormone receptor-positive/HER2-negative (HR+/HER2-). The reassessed tumor size and ypT category differed from the original report in 113 (60%) and 107 (57%) cases, respectively. In all of these cases the tumor size or ypT category was smaller/lower on review. The 107 cases with lower ypT categories included 41% of TNBCs, 62% of HER2+ and 64% of HR+/HER2- (p=0.02) In the original report, 36 (19%) cases were classified as multifocal versus 131 (69%) after review (p=0.00001). yAJCC staging based on the reassessed ypT categories differed from the original report in 38 (20%) cases (all down-staged). There were 77/189 (41%) cases with yAJCC/RCB Class discrepancies in the original reports versus 95/189 (50%) after slide review (p=0.08). The yAJCC/RCB discrepant cases in the original reports included 47% of TNBCs, 38% of HER2+ and 38% of HR+/HER2- versus 47% of TNBCs, 48% of HER2+ and 54% of HR+/HER2- after review (p=0.62). The higher proportion of discrepancies among HR+/HER2- after review did not reach statistical significance (p=0.06). Conclusions: Strict adherence to 8th Ed. yAJCC criteria for measurement of the residual breast tumor after NAC resulted in smaller tumor size, lower ypT category, lower yAJCC stage and more tumors classified as multifocal. Changes in ypT category occurred more often among HER2+ and HR+/HER2- than TNBC. There was no significant change in the frequency of yAJCC/RCB discrepancies.

Citation Format: Dawn Harter, Siobhan M O'Connor, Johann D Hertel, Benjamin C Calhoun. Breast tumor measurement after neoadjuvant chemotherapy using the 8th edition of the American Joint Committee on cancer staging system: Impact on estimates of tumor size and discrepancies with residual cancer burden class [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P1-02-10.

Clinicopathologic features of breast cancer reclassified as HER2-amplified by fluorescence in situ hybridization with alternative chromosome 17 probes

OBJECTIVE

Dual probe fluorescence in situ hybridization (FISH) assays for determination of human epidermal growth factor receptor 2 (HER2) gene amplification in breast cancer provide a ratio of HER2 to chromosome 17. The ratio may be skewed by copy number alterations (CNA) in the control locus for chromosome 17 (CEP17). We analyzed the impact of alternative chromosome 17 control probes on HER2 status in a series of breast cancers with an emphasis on patients reclassified as amplified.

METHODS

Breast cancer patients with equivocal HER2 immunohistochemistry (2+) and equivocal FISH with CEP17 were included. Reclassification of HER2 status was assessed with alternative chromosome 17 control probes (LIS1 and RARA).

RESULTS

A total of 40 unique patients with 46 specimens reflexed to alternative chromosome 17 probe testing were identified. The majority (>80%) of patients had pT1-2, hormone receptor-positive tumors with an intermediate or high combined histologic grade. There were 34/46 (73.9%) specimens reclassified as amplified with alternative probes, corresponding to 29/40 (72.5%) patients. Of the patients reclassified as amplified with alternative probes, 34.5% (10/29) received HER2-targeted therapy.

CONCLUSION

In this series, the majority of breast cancers tested with alternative chromosome 17 control probes under the 2013 ASCO/CAP Guidelines were converted to HER2-amplified. The treatment data and the clinicopathologic profile of the tumors suggest that most of these patients will neither receive nor benefit from HER2-targeted therapy. The findings support the recommendation in the 2018 ASCO/CAP HER2 Guidelines to discontinue the use of alternative chromosome 17 probes.

MRI-guided core needle biopsy of the breast: Radiology-pathology correlation and impact on clinical management

OBJECTIVE

Breast MRI is used to screen high-risk patients and determine extent of disease in breast cancer (BC) patients. The goal of this study was to determine the pathologic correlates of breast MRI abnormalities biopsied under MRI guidance.

METHODS

We retrospectively identified 101 MRI-guided core needle biopsies (CNB) of the breast from 79 women over a 4-year period. MRI-detected lesions biopsied with ultrasound or stereotactic guidance were excluded. MRI studies and pathology were reviewed by breast radiologists and pathologists.

RESULTS

Of the 79 patients, 72 (91%) had a history of prior (n = 13) or concurrent (n = 59) BC. There were 101 MRI abnormalities: 60 (59%) with non-mass enhancement (NME) and 41 (41%) with mass enhancement. Pathology was benign in 83/101 (82%), including in the majority of NME lesions (43/60, 72%). The most common benign findings were: fibrocystic changes (FCC) (49%), sclerosing lesions (13%), and fibroadenoma (FA) (9%). There were 18 (18%) malignant diagnoses: 8 (44%) invasive lobular carcinoma (ILC), 7 (39%) ductal carcinoma in situ (DCIS), and 3 (17%) invasive ductal carcinoma (IDC). Of the 18 malignant diagnoses, 16 (89%) occurred in 14 unique patients with concurrent BC. Based on the malignant MRI-guided CNB, 6 (46%) of these patients had additional (sentinel lymph node biopsy or contralateral breast surgery) or more extensive (wider lumpectomy) surgery.

CONCLUSION

In this series, most MRI-guided CNB of the breast were benign. The vast majority of malignant diagnoses occurred in patients with concurrent BC and frequently resulted in changes in clinical management.

Feasibility of Hepatitis B Vaccination by Microneedle Patch: Cellular and Humoral Immunity Studies in Rhesus Macaques

BACKGROUND

This study evaluated dissolvable microneedle patch (dMNP) delivery of hepatitis B vaccine in rhesus macaques and provides evidence that dMNP delivery elicits seroprotective anti-HBs levels comparable with human seroprotection, potentially useful for hepatitis B birth dose vaccination in resource-constrained regions.

METHODS

Sixteen macaques were each vaccinated twice; they were treated in 4 groups, with dMNP delivery of AFV at 24 ± 8 µg (n = 4) or 48 ± 14 µg (n = 4), intramuscular injection of AFV (10 µg; n = 4), or intramuscular injection of AAV (10 µg; n = 4). Levels of antibody to hepatitis B surface antigen (HBsAg) (anti-HBs) and HBsAg-specific T-cell responses were analyzed.

RESULTS

Six of 8 animals with dMNP delivery of AFV had anti-HBs levels ≥10 mIU/mL after the first vaccine dose. After dMNP delivery of AFV, interferon γ, interleukin 2, and interleukin 4 production by HBsAg-specific T cells was detected. A statistically significant positive correlation was detected between anti-HBs levels and cells producing HBsAg-specific interferon γ and interleukin 2 (T-helper 1-type cytokine) and interleukin 4 (T-helper 2-type cytokine) in all anti-HBs-positive animals.

CONCLUSIONS

dMNP delivery of AFV can elicit seroprotective anti-HBs levels in rhesus macaques that are correlated with human seroprotection, and it could be particularly promising for birth dose delivery of hepatitis B vaccine in resource-constrained regions.

Hepatitis B vaccination using a dissolvable microneedle patch is immunogenic in mice and rhesus macaques

Chronic Hepatitis B virus infection remains a major global public health problem, accounting for about 887,000 deaths in 2015. Perinatal and early childhood infections are strongly associated with developing chronic hepatitis B. Adding a birth dose of the hepatitis B vaccine (HepB BD) to routine childhood vaccination can prevent over 85% of these infections. However, HepB BD coverage remains low in many global regions, with shortages of birth attendants trained to vaccinate and limited HepB BD supply at birth. To address the challenges, we developed coated metal microneedle patches (cMNPs) and dissolvable microneedle patches (dMNPs) that deliver adjuvant‐free hepatitis B vaccine to the skin in a simple‐to‐administer manner. The dMNP contains micron‐scale, solid needles encapsulating vaccine antigen and dissolve in the skin, generating no sharps waste. We delivered HepB BD via cMNP to BALB/c mice and via dMNP to both mice and rhesus macaques. Both cMNP and dMNP were immunogenic, generating hepatitis B surface antibody levels similar to human seroprotection. Biomechanical analysis showed that at high forces the microneedles failed mechanically by yielding but microneedles partially blunted by axial compression were still able to penetrate skin. Overall, this study indicates that with further development, dMNPs could offer a method of vaccination to increase HepB BD access and reduce needle waste in developing countries.

Northern Italy in the American South: Assessing interobserver reliability within the Milan System for Reporting Salivary Gland Cytopathology

BACKGROUND

The Milan System for Reporting Salivary Gland Cytopathology (MSRSGC) has been proposed to standardize salivary gland fine-needle aspiration (FNA) diagnoses. This study assessed salivary gland FNA results and risk of malignancy (ROM) rates at the University of North Carolina as well as the interobserver reliability (IOR) of the atypia of undetermined significance (AUS) and salivary gland neoplasm of uncertain malignant potential (SUMP) categories.

METHODS

The electronic medical record was searched for FNA cases from 2010 to 2017 with subsequent surgical resections. Histologic diagnosis was used for gold-standard comparison. The original cytologic results were then converted into MSRSGC categories (nondiagnostic, nonneoplastic, AUS, benign neoplasm, SUMP, suspicious, and malignant). For the assessment of IOR, 23 cases were selected with enrichment for cases diagnosed as AUS (n = 11) or SUMP (n = 9). Six boarded cytopathologists and 1 cytopathology fellow assessed representative slides and provided an MSRSGC diagnosis for each case. Fleiss' κ coefficients were calculated to determine IOR.

RESULTS

The ROM was 33% for both AUS and SUMP cases; however, the risk of neoplasia was 56% for AUS cases and 100% for SUMP cases. Fleiss' κ for the AUS category was 0.217 (P < .05), and Fleiss' κ for the SUMP category was 0.024 (P = .74).

CONCLUSIONS

In this study assessing the IOR of MSRSGC categories, fair agreement and slight agreement were found for the AUS and SUMP categories, respectively. Observers preferentially used the AUS or benign neoplasm category for SUMP cases, perhaps because of unfamiliarity with SUMP as a diagnostic option. The initial adoption of a new reporting system will require a quality assessment to ensure that the system is reliable and useful for clinicians. Cancer Cytopathol 2018;126:390-6. © 2018 American Cancer Society.

Ductal Carcinoma In Situ Simultaneously Involving the Breast and Epithelial Inclusions in an Ipsilateral Axillary Lymph Node

Benign cystic epithelial inclusions with squamous, glandular, or Müllerian phenotypes are known to occur in the axillary lymph nodes of patients with benign and malignant breast disease. Careful evaluation of hematoxylin and eosin-stained slides and correlation with the histologic findings in the ipsilateral breast are paramount in evaluation of suspected benign inclusions. In this case of ductal carcinoma in situ (DCIS) of the breast in a 73-year-old woman, DCIS also involved epithelial inclusions in an ipsilateral axillary lymph node. The recognition of these benign epithelial elements, and awareness that they can be involved by DCIS, is crucial to avoid the overdiagnosis of metastatic carcinoma.

Molecular and cellular heterogeneity in breast cancer: challenges for personalized medicine

Breast cancer is noted for disparate clinical behaviors and patient outcomes, despite common histopathological features at diagnosis. Molecular pathogenesis studies suggest that breast cancer is a collection of diseases with variable molecular underpinnings that modulate therapeutic responses, disease-free intervals, and long-term survival. Traditional therapeutic strategies for individual patients are guided by the expression status of the estrogen and progesterone receptors (ER and PR) and human epidermal growth factor receptor 2 (HER2). Although such methods for clinical classification have utility in selection of targeted therapies, short-term patient responses and long-term survival remain difficult to predict. Molecular signatures of breast cancer based on complex gene expression patterns have utility in prediction of long-term patient outcomes, but are not yet used for guiding therapy. Examination of the correspondence between these methods for breast cancer classification reveals a lack of agreement affecting a significant percentage of cases. To realize true personalized breast cancer therapy, a more complete analysis and evaluation of the molecular characteristics of the disease in the individual patient is required, together with an understanding of the contributions of specific genetic and epigenetic alterations (and their combinations) to management of the patient. Here, we discuss the molecular and cellular heterogeneity of breast cancer, the impact of this heterogeneity on practical breast cancer classification, and the challenges for personalized breast cancer treatment.

Effect of laundry activities on in-stream concentrations of linear alkylbenzene sulfonate in a small rural South African river

In many parts of the world clothes are washed near to or in rivers and streams. Little information is available on resulting concentrations of detergent ingredients or on any potential effects caused. In this study, the fate of a commonly used anionic surfactant, linear alkylbenzene sulphonate (LAS) was investigated in a reach of the Balfour River (Eastern Cape Province, South Africa) which was regularly used as a site for laundry activity. Samples of river water were collected upstream of the main washing site and at a number of locations downstream on several occasions in winter and summer. Sediment samples were also collected and analysed. In addition, a household survey was conducted to ascertain the amount of detergent used and the distribution of washing practices. The results of the survey suggested that the use of riverside locations for laundry activities was seasonal. Most washing tended to be done at home during the winter with riverside sites used more frequently during the summer months. The monitoring data showed that LAS concentrations in water were very variable. They were occasionally high in the immediate vicinity of the laundry site (up to 342 microg L(-1)) but were generally very low (<11 microg L(-1)) at downstream monitoring stations, suggesting that LAS was rapidly dissipated by a combination of degradation, hydrodynamic dispersion and dilution. Concentrations in the immediate vicinity of the washing site were lower than expected on the basis of the household survey because most waste water was disposed of on the river bank rather than directly in the river. No ecological effects are expected from LAS emissions at this site.

A 16-year-old male with a cerebellar mass

A 16-year-old male presented to an emergency room after falling on his head while inebriated. The patient had only a history of recent fatigue and demonstrated no focal neurological deficit. MRI revealed a cystic and solid, enhancing midline cerebellar lesion. A suboccipital craniotomy was performed. Histologically, the mass showed large bizarre cells arranged in sheets with admixed small lymphocytes. The pleomorphic population had ample glassy eosinophilic cytoplasm and intranuclear inclusions. An infiltrating component resembling diffuse astrocytoma could be found in areas. Rosenthal fibers were particularly abundant in the areas of infiltrating glioma. Mitotic activity was very low, and necrosis was absent. Reticulin fibers between individual cells were focally abundant. Glial fibrillary acidic protein and vimentin were strongly expressed in many cells, while synaptophysin and neurofilament protein were not. Ki-67 showed a very low proliferation index. The pathologic diagnosis was pleomorphic xanthoastrocytoma (PXA) of the cerebellum. PXA is a diagnosis typically regarded as a superficial meningocerebral neoplasm. This case is one of sixteen cerebellar PXAs reported in the literature.

Multielectrode impedance tuning: reducing noise and improving stimulation efficacy

Multielectrode arrays (MEAs) have emerged as a leading technology for extracellular, electrophysiological investigations of neuronal networks. The study of biological neural networks is a difficult task that is further confounded by mismatches in electrode impedance. Electrode impedance plays an important role in shaping incoming signals, determining thermal noise, and influencing the efficacy of stimulation. Our approach to optimally reduce thermal noise and improving the reliability of stimulation is twofold minimize the impedance and match it across all electrodes. To this aim, we have fabricated a device that allows for the automated, impedance-controlled electroplating of micro-electrodes. This device is capable of rapidly (minutes) producing uniformly low impedances across all electrodes in an MEA. The need for uniformly low impedances is important for controlled studies of neuronal networks; this need will increase in the future as MEA technology scales from tens of electrodes to thousands.

Agitation in Alzheimer's disease is a manifestation of frontal lobe dysfunction

OBJECTIVES

(1) To investigate the prevalence and characteristics of agitation in patients with Alzheimer's disease (AD) and other forms of dementia; (2) to explore the association between agitation and other clinical variables, including disease severity, functional impairment and other neuropsychiatric symptoms, and (3) to determine the predictors of agitation.

METHODS

Data for 427 men and women with dementia from outpatient clinics of the University of California, Los Angeles Alzheimer's Disease Center were analyzed. There were 277 patients with AD, 43 with vascular dementia, 47 with mixed dementia, 45 with frontotemporal dementia and 15 with dementia with Lewy bodies. Patients were evaluated with the Mini-Mental State Examination (MMSE), Neuropsychiatric Inventory (NPI), Functional Activities Questionnaire (FAQ), neuropsychological tests and the Caregiver Appraisal instrument. SPSS10 was utilized for statistical analysis.

RESULTS

There was no difference in agitation subscale scores among patients with dementia of various etiologies. In patients with AD, there was increased prevalence of agitation with increasing dementia severity. Agitation contributed substantially to caregiver burden and impact. There was a significant correlation between the FAQ and the NPI agitation subscale score after adjusting for MMSE scores. Delusion, disinhibition and irritability subscale scores in AD patients were correlated with agitation across disease severity. Subscale scores of frontally mediated behaviors including irritability, delusions and disinhibition predicted most of the variance in agitation levels.

CONCLUSION

Agitation is common in AD and other dementias and has a marked impact on caregivers. It is related to dementia severity and to specific types of associated psychopathology implicating frontal lobe dysfunction. The present study is the largest and most comprehensive assessment of agitation reported. The data suggest that agitation in AD is a frontal lobe syndrome. Frontal lobe dysfunction may predispose AD patients to agitation by exaggerating behavioral responses to many types of coexisting psychopathology or environmental provocations.

Shed membrane fragment modulation of CD3-zeta during pregnancy: link with induction of apoptosis

Our objective was to identify shed placental plasma membrane fragments in the maternal circulation and determine whether these fragments are capable of down-regulating CD3-zeta chain expression and inducing apoptosis in T lymphocytes. Sera, isolated from the blood of pregnant women at 26-29 weeks gestation that subsequently had uncomplicated term deliveries, were subjected to high exclusion-limit gel chromatography to isolate placental membrane fragments. The placental origin of the fragments was confirmed by the presence of placental-type alkaline phosphates. These shed membrane fragments were further analyzed for the presence of Fas ligand (FasL) and modulation of CD3-zeta expression on cultured T-lymphocytes (Jurkat cells). The ability of the shed membrane fragments to induce apoptosis was assayed using a cell death ELISA. Components associated with Fas-dependent apoptosis (caspase-3, bcl-2 and bax) were characterized using western immunoblot following exposure to serum-derived membrane fragments. Placental membrane fragments were identified in all pregnancy sera, but not in non-pregnant controls. The 41 kDa FasL was identified in membrane fragment isolates and all samples were capable of inducing apoptosis as determined by the ELISA assay. Exposure of T lymphocytes to isolated membrane fragments suppressed the expression of CD3-zeta. The induction of apoptosis correlated with the induction and activation of caspase 3 and the induction of bax. Placenta-derived membrane fragments are detectable in the maternal circulation. These membrane fragment isolates are capable of inducing FasL-mediated apoptosis and down-regulating CD3-zeta expression, which may contribute to the immune tolerance of the fetus.

Anaerobic benzene oxidation coupled to nitrate reduction in pure culture by two strains of Dechloromonas

Benzene contamination is a significant problem. It is used in a wide range of manufacturing processes and is a primary component of petroleum-based fuels. Benzene is a hydrocarbon that is soluble, mobile, toxic and stable, especially in ground and surface waters. It is poorly biodegraded in the absence of oxygen. However, anaerobic benzene biodegradation has been documented under various conditions. Although benzene biomineralization has been demonstrated with nitrate, Fe(III), sulphate or CO2 as alternative electron acceptors, these studies were based on sediments or microbial enrichments. Until now there were no organisms in pure culture that degraded benzene anaerobically. Here we report two Dechloromonas strains, RCB and JJ, that can completely mineralize various mono-aromatic compounds including benzene to CO2 in the absence of O2 with nitrate as the electron acceptor. This is the first example, to our knowledge, of an organism of any type that can oxidize benzene anaerobically, and we demonstrate the potential applicability of these organisms to the treatment of contaminated environments.

Survival and neurite outgrowth of rat cortical neurons in three-dimensional agarose and collagen gel matrices

To better understand interactions between neurons and extracellular matrix equivalents, embryonic day-18 rat cortical neurons were immobilized and maintained in culture for up to 24 days in agarose and type I collagen gels. Using live/dead staining, neuronal cultures in low density collagen gel lasted at least 3 weeks. At 14 days, over 50% of immobilized cells in collagen gel were found viable while in low density agarose gel no cells survived. In situ cell death detection showed that most, if not all, dead cells in either of the gels underwent apoptosis. The collagen-trapped neurons exhibited normal neuronal polarity and developed long neurites, estimated at over 500 microm. The results suggest that collagen, because it is a major extracellular matrix constituent, suppresses apoptosis and provides a suitable substrate for neuronal survival and differentiation.

Cognitive and metabolic responses to metrifonate therapy in Alzheimer disease

OBJECTIVE

The objective of this study was to identify the relation between the cognitive benefit seen with the cholinesterase inhibitor metrifonate and changes in brain metabolism as visualized with [18F]-fluorodeoxyglucose positron emission tomography (FDG-PET).

BACKGROUND

The regional metabolic correlates of treatment with cholinesterase inhibitors are poorly understood.

METHODS

Six patients with mild to moderate Alzheimer disease (AD) were evaluated before and after treatment with the long-lasting cholinesterase inhibitor metrifonate. Patients were given 60 or 80 mg of metrifonate per day (based on weight) for 6 to 12 weeks. Clinical evaluations included the cognitive portion of the Alzheimer's Disease Assessment Scale (ADAS-cog), the Mini-Mental State Examination (MMSE), and the Neuropsychiatric Inventory. Imaging was carried out using FDG-PET. The PET studies, registered to a probabilistic anatomic atlas, were normalized across the group's mean intensity levels and subjected to voxel-by-voxel subtraction of the posttreatment minus pretreatment studies. Subvolume thresholding corrected random lobar noise to produce a three-dimensional functional significance map.

RESULTS

The criteria for cognitive improvement with treatment were met for the MMSE (>2 points improvement from baseline), and the drawing subscale of the ADAS-cog was significantly improved with treatment. The three-dimensional significance map revealed a significant metabolic increase of the dorsolateral frontoparietal network on the left and bilateral temporal cortex with metrifonate treatment.

CONCLUSION

The clinical benefits observed in AD with cholinesterase inhibitor therapy are associated with a metabolic increase of heteromodal cognitive and medial temporal networks.

Primary neural precursor cell expansion, differentiation and cytosolic Ca(2+) response in three-dimensional collagen gel

To investigate the ability to culture neural precursor cells in a three-dimensional (3D) collagen gel, neuroepithelial cells were isolated from embryonic day 13 rat cortex, dispersed within type I collagen and maintained for up to 30 days in vitro. Cultured in Neuorobasal medium supplemented with B27 containing basic fibroblast growth factor, the collagen-entrapped precursor cells actively expanded and formed clone-like clusters. Many cells in the center of the cluster were proliferating as revealed by 5-bromo-2'-deoxyuridine uptake. Some cells began to migrate away from the center at 5 days and were labeled by either neuronal marker neuron-specific beta-tubulin (TuJ1) or astrocytic marker glial fibrillary acidic protein. The differentiated neurons (TuJ1(+)) exhibited characteristic cytosolic Ca(2+) oscillations in response to excitatory neurotransmitter glutamate. These findings suggest the suitability of the 3D culture system for the proliferation and differentiation of neural precursor cells.

Orbital and dorsolateral frontal perfusion defect associated with behavioral response to cholinesterase inhibitor therapy in Alzheimer's disease

The authors retrospectively explored the behavioral and functional imaging profile of Alzheimer's disease (AD) patients who respond to cholinesterase inhibitor therapy by using the Neuropsychiatric Inventory (NPI) and baseline [99mTc]HMPAO SPECT. Thirty AD patients were divided into three groups (Responders, Nonresponders, and Unchanged) based on their behavioral response to donepezil. Responders had significantly (P < or = 0.01) more pretreatment irritability, disinhibition (P < or = 0.05), and euphoria (P = 0.05) than Nonresponders and significantly lower lateral orbital frontal (P < 0.00001) and dorsolateral frontal (P < or = 0.0005) perfusion bilaterally. A pretreatment orbitofrontal syndrome may predict behavioral response to cholinesterase inhibitor therapy in AD.

Sustained release of silver from periodontal wafers for treatment of periodontitis

Periodontal wafers intended to treat the underlying infections in patients with periodontitis have been developed. The wafers consist of poly(lactic-co-glycolic acid) as a primary bioerodible polymeric component, poly(ethylene glycol) as a plasticizer and encapsulation aid, and silver nitrate as the antimicrobial agent. The wafers are capable of sustained in vitro release of bioactive silver for at least 4 weeks. The wafers exhibit silver release that follows erosion kinetics, confirming a bulk erosion/release mechanism. In clinical evaluation, sustained release of silver at bactericidal levels for at least 21 days is observed. Staining of hard and soft tissues due to the released silver is minimal and reversible.

Immobilization of neural cells in three-dimensional matrices for biosensor applications

To overcome logistical difficulties with current designs of cell- or tissue-based biosensors which have individual cells or tissue slices immobilized on membranes or microelectrode arrays, we have proposed a system that uses three-dimensional cultures of neural cells immobilized in hydrogel matrices. In this design, immobilized cells would be maintained in a reservoir and then transferred to a detector platform when needed for analysis. The development of such a system relies upon a renewable supply of cells and the ability to culture cells for long periods of time in three-dimensions while maintaining their physiological function. To investigate the ability to culture neural cells in 3D matrices, embryonic rat cortical neurons and astrocytes were immobilized by matrix entrapment in a novel sugar poly(acrylate) hydrogel and collagen gels. The sugar poly(acrylate) hydrogel does not appear to support neural cell growth as a result of a lack of cell adherence, small pore size and, possibly, harshness of synthesis conditions. In contrast, collagen gels support the growth of cortical neurons, astrocytes, as well as neural progenitor cells. Evidence is also presented from immunocytochemistry and patch-clamp measurements which shows that neural progenitor cells proliferate in culture and can be induced to differentiate into neural cell types. Thus, they potentially represent a renewable cell source.

Ubiquity and diversity of dissimilatory (per)chlorate-reducing bacteria

Environmental contamination with compounds containing oxyanions of chlorine, such as perchlorate or chlorate [(per)chlorate] or chlorine dioxide, has been a constantly growing problem over the last 100 years. Although the fact that microbes reduce these compounds has been recognized for more than 50 years, only six organisms which can obtain energy for growth by this metabolic process have been described. As part of a study to investigate the diversity and ubiquity of microorganisms involved in the microbial reduction of (per)chlorate, we enumerated the (per)chlorate-reducing bacteria (ClRB) in very diverse environments, including pristine and hydrocarbon-contaminated soils, aquatic sediments, paper mill waste sludges, and farm animal waste lagoons. In all of the environments tested, the acetate-oxidizing ClRB represented a significant population, whose size ranged from 2.31 x 10(3) to 2.4 x 10(6) cells per g of sample. In addition, we isolated 13 ClRB from these environments. All of these organisms could grow anaerobically by coupling complete oxidation of acetate to reduction of (per)chlorate. Chloride was the sole end product of this reductive metabolism. All of the isolates could also use oxygen as a sole electron acceptor, and most, but not all, could use nitrate. The alternative electron donors included simple volatile fatty acids, such as propionate, butyrate, or valerate, as well as simple organic acids, such as lactate or pyruvate. Oxidized-minus-reduced difference spectra of washed whole-cell suspensions of the isolates had absorbance maxima close to 425, 525, and 550 nm, which are characteristic of type c cytochromes. In addition, washed cell suspensions of all of the ClRB isolates could dismutate chlorite, an intermediate in the reductive metabolism of (per)chlorate, into chloride and molecular oxygen. Chlorite dismutation was a result of the activity of a single enzyme which in pure form had a specific activity of approximately 1,928 micromol of chlorite per mg of protein per min. Analyses of the 16S ribosomal DNA sequences of the organisms indicated that they all belonged to the alpha, beta, or gamma subclass of the Proteobacteria. Several were closely related to members of previously described genera that are not recognized for the ability to reduce (per)chlorate, such as the genera Pseudomonas and Azospirllum. However, many were not closely related to any previously described organism and represented new genera within the Proteobacteria. The results of this study significantly increase the limited number of microbial isolates that are known to be capable of dissimilatory (per)chlorate reduction and demonstrate the hitherto unrecognized phylogenetic diversity and ubiquity of the microorganisms that exhibit this type of metabolism.

The spectrum of behavioral responses to cholinesterase inhibitor therapy in Alzheimer disease

BACKGROUND

Behavioral abnormalities are common in Alzheimer disease (AD); cholinergic treatment reduces the behavioral disturbances of some patients with AD. Characterizing the pretreatment profile of patients who are likely to respond to cholinergic therapy will aid the efficient use of clinical resources.

OBJECTIVE

To determine the baseline behavioral profile for 86 patients with AD treated with the cholinesterase inhibitor donepezil hydrochloride.

METHODS

Open-label retrospective study of treatment-related behavioral assessments. Based on previous double-blind placebo-controlled experience using the Neuropsychiatric Inventory (NPI), patients were divided into responder (> or =4-point total NPI score decrease, indicating improvement), unchanged (+/-3-point total NPI score change), or nonresponder (> or =4-point total NPI score increase, indicating worsening) groups. The Mini-Mental State Examination assessed cognitive response.

RESULTS

Behavioral improvement was seen in 35 patients (41%), worsening in 24 (28%), and no change in 27 (31%). Comparison of profiles in behavioral responders vs nonresponders revealed significantly worse delusions (P = .04), agitation (P = .04), depression (P = .006), anxiety (P = .02), apathy (P = .003), disinhibition (P = .02), and irritability (P<.001) at baseline in responders. Five behaviors changed significantly from baseline, improving for the responders and worsening for the nonresponders: delusions (P = .003 for nonresponders, P = .004 for responders), agitation (P = .01), anxiety (P = .006 for nonresponders, P = .004 for responders), disinhibition (P = .02 for nonresponders, P = .05 for responders), and irritability (P = .003 for nonresponders, P = .001 for responders). The behavioral changes were dose dependent. Cognition did not change significantly with donepezil treatment within any group.

CONCLUSIONS

Donepezil has psychotropic properties, and pretreatment behaviors help predict patients' responses to treatment.

Compliance and functional residual capacity after staple versus combined staple/holmium laser lung volume reduction surgery in a rabbit emphysema model

BACKGROUND

There is some evidence to suggest that laser exposure, when added to standard staple reduction techniques, may result in improved physiologic response to lung volume reduction surgery (LVRS). In this study, we compared physiologic responses of staple LVRS with combined staple/laser in a rabbit emphysema model.

METHODS

Ninety-three New Zealand White rabbits underwent emphysema induction with aerosolized elastase 4 weeks before surgery and were killed 1 week after surgery. Treatment groups were bilateral moderate volume staple LVRS (< or =3 g, n = 39), combined moderate volume staple (< or =3 g)/holmium laser LVRS (n = 18), large-volume staple LVRS (> or =3 g, n = 27), or sham surgery (n = 9).

RESULTS

Decrease in postoperative static respiratory system compliance by combined moderate-volume staple/laser treatment (1.22 cc/cm H2O) was similar to large-volume staple resection (1.40 cc/cm H2O, p = 0.39), and superior to moderate staple resection (0.82 cc/cm H2O, p = 0.01) or sham surgery (0.09 cc/cm H2O, p = 0.0001). Functional residual capacity decrease was greater after combined moderate staple/laser resection (6.46 cc) than large-volume staple resection (4.52 cc, p = 0.33), moderate-volume staple resection (4.59 cc, p = 0.43), or sham surgery (4.10 cc, p = 0.29). Perioperative mortality was highest after laser/staple LVRS (22%, 4/18).

CONCLUSIONS

In this rabbit model, combined staple/ holmium laser reduction for emphysema results in significant improvement in compliance and trends toward improvement in functional residual capacity above staple reduction alone, but with higher mortality.

Anatomical loops and their electrical dynamics in relation to whisking by rat

An accumulation of anatomical, behavioral, and electrophysiological evidence allows us to identify the neuronal circuitry that is involved with vibrissa-mediated sensation and the control of rhythmic vibrissa movement. Anatomical evidence points to a multiplicity of closed sensorimotor loops, while electrophysiological data delineate the flow of electrical signals in these pathways. These loops process sensory input from the vibrissae and send projections to direct vibrissa movement, starting at the level of the hindbrain and proceeding toward loops that involve multiple structures in the forebrain. The nature of the vibrissa-related electrical signals in behaving animals has been studied extensively at the level of neocortical loops. Two types of spike signal are observed that serve as a reference of vibrissa motion: a fast signal that correlates with the relative phase of the vibrissae within a whisk cycle and a slow signal that correlates with the amplitude, and possibly the set-point, of the vibrissae during a whisk. Both signals are observed in vibrissa primary sensory (S1) cortex, and in some cases they are sufficiently robust to allow vibrissa position to be accurately estimated from the spike train of a single neuron. Unlike the case for S1 cortex, only the slow signal has been observed in vibrissa primary motor (M1) cortex. The control capabilities of M1 cortex were estimated from experiments with anesthetized animals in which progressive areas along the vibrissa motor branch were microstimulated with rhythmically applied currents. The motion of the vibrissae followed stimulation of M1 cortex only for rates that were well below the frequency of rhythmic whisking; in contrast, the vibrissae followed stimulation of the facial nucleus, whose cells directly drive the vibrissae, for rates above that of whisking. In toto, the evidence implies that there is fast signaling from the facial nucleus, through the mystacial pad and the vibrissae and up through sensory cortex, but only slow signaling at the level of the motor cortex and down through the superior colliculus to the facial nucleus. The transformation from fast sensory signals to slow motor control is an unresolved issue. On the other hand, there is a candidate scheme to understand how the fast reference of vibrissa motion in the whisk cycle may be used to decode the angle of the vibrissae upon their contact with an object. We discuss a circuit in which servo mechanisms are used to determine the angle of contact relative to the preferred phase of the fast reference signals. Support for this scheme comes from results with anesthetized animals on the frequency and phase entrainment of intrinsic neuronal oscillators in S1 cortex. A prediction based on this scheme is that the output from a decoder circuit is maximal when the angle of contact differs from the preferred phase of a fast regerence signal. In contrast, for correlation-based schemes the output is maximal when the angle of contact equals the preferred phase.

Circumstances around weapon injury in Cambodia after departure of a peacekeeping force: prospective cohort study

OBJECTIVE

To examine the circumstances surrounding weapon injury and combatant status of those injured by weapons.

DESIGN

Prospective cohort study.

SETTING

Northwestern Cambodia after departure of United Nations peacekeeping force.

SUBJECTS

863 people admitted to hospital for weapon injuries over 12 months.

MAIN OUTCOME MEASURES

Annual incidence of weapon injury by time period; proportions of injuries inflicted as a result of interfactional combat (combat injuries) and outside such combat (non-combat injuries) by combatant status and weapon type.

RESULTS

The annual incidence of weapon injuries was higher than the rate observed before the peacekeeping operation. 30% of weapon injuries occurred in contexts other than interfactional combat. Most commonly these were firearm injuries inflicted intentionally on civilians. Civilians accounted for 71% of those with non-combat injuries, 42% of those with combat related injuries, and 51% of those with weapon injuries of either type.

CONCLUSIONS

The incidence of weapon injuries remained high when the disarmament component of a peacekeeping operation achieved only limited success. Furthermore, injuries occurring outside the context of interfactional combat accounted for a substantial proportion of all weapon injuries, were experienced disproportionately by civilians, and were most likely to entail the intentional use of a firearm against a civilian.

An intronic silencer regulates B lymphocyte cell- and stage-specific expression of the human complement receptor type 2 (CR2, CD21) gene

Human CR2 (CD21) is a B lymphocyte protein whose surface expression is restricted primarily to the mature cell stage during development. To study the transcriptional mechanisms that govern cell- and stage-restricted CR2 expression, we first performed transient transfection analysis using constructs extending from -5 kb to +75 bp (-5 kb/+75) in the CR2 promoter. The promoter was found to be broadly active, with no evidence of cell- or stage-specific reporter gene expression. However, the addition of a 2.5-kb intronic gene segment (containing a DNase I hypersensitive site) to the (-5-kb/+75) construct resulted in appropriate reporter gene expression, defined as the silencing of the (-5-kb/+75) promoter activity only in non-CR2-expressing cells. Interestingly, appropriate reporter gene expression required stable transfection of the constructs in cell lines, suggesting nuclear matrix or chromatin interactions may be important for appropriate CR2 gene expression. Importantly, transgenic mice also required the intronic silencer to generate lymphoid tissue-specific reporter gene expression. Some transgenic founder lines did not demonstrate reporter gene expression, however, indicating that additional transcriptional regulatory elements are present in other regions of the CR2 gene. In summary, these data support the hypothesis that human CR2 expression is regulated primarily by an intronic silencer with lineage- and B cell stage-specific activity.

Fibrinogen-dependent adherence of macrophages to surfaces coated with poly(ethylene oxide)/poly(propylene oxide) triblock copolymers

The role of fibrinogen in the adherence of macrophages to polymer surfaces was studied using a human cell line (THP-1 cells) and polystyrene-divinylbenzene beads coated with poly(ethylene oxide)/poly(propylene oxide) copolymers of the form PEO alpha PPO beta PEO alpha. The amphiphilic character of the surface of the beads was varied using a series of copolymers with constant PPO core lengths but different PEO segments. Fibrinogen-dependent adherence of monocytes/macrophages to the modified beads was then assessed. The adherence of THP-1 cells to copolymer-coated beads correlates well with the amount of fibrinogen bound to the beads. Those beads coated with the most hydrophobic surfactant molecules bound the most fibrinogen and the most cells. On these surfaces, the concentration of fibrinogen was less than half that of the protein on unmodified beads. Despite the lower amount of bound fibrinogen, the number of adherent cells was 37% greater than the number of adherent cells on fibrinogen-coated, copolymer-free beads. Beads coated with the most hydrophilic surfactants bound just 10% the amount of fibrinogen bound to unmodified beads. On these surfaces, the number of adherent cells was decreased by approximately 25% with respect to the number of cells bound to beads coated with fibrinogen alone. We propose that the hydrophobic surfactant molecules may act as inflammatory agents by facilitating fibrinogen-dependent cellular adhesion.

Null alleles of creA, the regulator of carbon catabolite repression in Aspergillus nidulans

CreA is the major regulatory protein involved in carbon catabolite repression in Aspergillus nidulans. Previously we have reported the molecular characterization of a number of in vivo selected mutant alleles and showed that they were unlikely to represent total loss of function alleles (Shroff et al., 1996) and that a deletion of the creA gene and surrounding DNA has an extremely severe effect on morphology under both carbon catabolite repressing and carbon catabolite nonrepressing conditions (Dowzer and Kelly, 1991). Here we present an analysis of in vivo selected creA mutations with an extreme morphological phenotype and show that some of these alleles would be predicted to result in no functional CreA. The most extreme of these alleles resulted in a truncation of the protein within the first zinc finger. Precise gene disruptions, leaving the flanking sequences intact, show essentially the same phenotype as this truncated allele. Thus, a strain containing a null allele is viable, and the leaky-lethal phenotype of previous deletion alleles (Dowzer and Kelly, 1991) must be due to the deletion of additional 3' genomic sequence. A strain containing an allele that results in a deletion of the final 80 amino acids shows reduced sensitivity to carbon catabolite repression for a number of systems, thus localizing a region of the protein involved in repression. Surprisingly, the phenotypically most extreme allele studied is not a null allele, but results in an amino acid substitution that would disrupt the zinc finger region and abolish binding to DNA. This is the only allele that produces a full-length protein, predicted to be nuclear localized, but which completely abolishes DNA binding. The phenotype may be more extreme than the null alleles due to the nuclear located CreA protein titrating interacting proteins.

Inhibition of experimental gingivitis in beagle dogs with topical salivary histatins

Histatins, histidine-rich proteins found within parotid and submandibular secretions, are a novel class of endogenous peptides with antimicrobial properties. This masked, randomized, placebo-controlled preclinical investigation examined the effect of 3 topical histatins on the development of plaque and gingivitis in beagle dogs. 16, female, 1-year-old beagles were brought to optimal gingival health by mechanical scaling and polishing followed by rigorous daily tooth brushing. At the conclusion of this pretreatment period, dogs were randomly divided into 4 groups for the application of test formulations, and were placed on a plaque-promoting diet. Test agents included 3 synthetic salivary histatins (histatin 5, P-113 and P-113D) which were incorporated in hydroxypropyl methylcellulose gel at a concentration of 0.125%, and a placebo, or negative control, which was the gel vehicle alone. Throughout the 10-week treatment period, test formulations (2.0 ml) were applied 2 x daily to all premolar teeth using a Monojet syringe. Plaque formation and gingival inflammation were assessed using the plaque (PI) and gingival (GI) indices on days 0, 7, 14, 21, 28, 42, 56 and 70. Furthermore, bleeding to probing was recorded as a percent of sites (%BOP) and according to the modified sulcus bleeding index (mSBI). Comparisons among groups and between group pairs (active versus placebo) were made with Kruskal-Wallis tests with the average of data over the interval, days 14-42, being the primary focus of the analysis. From baseline to day 7, all groups expressed similar indices. Thereafter, overall significant differences among the groups were noted at day 42 for PI, at days 21, 28, 42 and 70 for GI, and at days 14 and 28 for %BOP (p < 0.05). In particular, beagles treated with P-113 demonstrated significantly lower PI scores at day 42 (p < 0.05), significantly lower GI scores from days 21 through 42 (p < 0.05), and significantly lower %BOP scores at days 14 and 28 (p < 0.05) compared to beagles treated with placebo. Beagles treated with P-113D exhibited significantly lower GI at day 42 compared to the placebo (p < 0.05). For the primary analysis conducted over the midtreatment interval (days 14-42), significant differences were detected for all parameters except mSBI (p < 0.05). Accordingly, significantly lower PI scores were found for P-113, lower GI scores for P-113 and P-113D, and lower %BOP for P-113 and P-113D compared to placebo (p < 0.05). These data indicate that in the beagle model, salivary histatins, P-113 and P-113D, topically applied, can significantly reduce clinical signs of plaque formation and gingival inflammation.

Lack of agreement between measurement of ejection fraction by impedance cardiography versus radionuclide ventriculography

OBJECTIVE

To determine the limits of agreement between left ventricular ejection fraction estimated using systolic time intervals from impedance cardiography and left ventricular ejection fraction estimated by radionuclide ventriculography.

DESIGN

A prospective study for diagnostic tests using radionuclide ventriculography as the criterion standard.

SETTING

A large military teaching hospital.

PATIENTS

Twenty ambulatory adults scheduled for radionuclide ventriculography.

MEASUREMENTS AND MAIN RESULTS

A regression equation to estimate ejection fraction from systolic time intervals is available in a widely used impedance-based cardiac monitoring device. The estimated ejection fraction is then used in an equation with stroke volume estimated by the same device to calculate an end-diastolic volume. We studied the agreement of the ejection fraction as estimated by this device with the ejection fraction estimated by radionuclide ventriculography by obtaining simultaneous estimates of ejection fraction over a broad range of adult patients. Twenty ejection fraction pairs were analyzed. The correlation of ejection fraction by impedance cardiography to ejection fraction by radionuclide ventriculography was significant (r2 = .55; p < .002). However, the mean difference between the technologies was -8.85%, with a standard deviation of the differences of 7.15%, resulting in a 95% confidence range for agreement of -23.2% to +5.5%.

CONCLUSIONS

The 95% confidence range defining the limits of agreement between ejection fraction by impedance cardiography and ejection fraction by radionuclide ventriculography is not clinically acceptable. In the opinion of the authors impedance cardiography should not be used in place of radionuclide ventriculography for the assessment of ejection fraction at this time.

Lumbar intervertebral disc herniation: treatment by rotational manipulation

We describe the case of a patient with a lumbar disc herniation who underwent a course of side posture manipulation. Despite the appearance of an enormous central herniation on the CT scan, the patient improved considerable during only 2 wk of treatment. The disparity which so commonly exists between radiological and clinical findings is depicted in this case. Further, it is emphasized that manipulation has been shown to be an effective treatment for some patients with lumbar disc herniation. While complications of this form of treatment have been reported in the literature, such incidents are rare.

Prospective study of antecedents for nonorganic failure to thrive

The cause of nonorganic failure to thrive (NFT) was studied prospectively in 274 low-income pregnant mothers by interviewing them for characteristics that retrospective studies indicated were associated with child maltreatment. After delivery, medical charts of mothers and infants were reviewed for complications of pregnancy, delivery, and postdelivery hospitalization, and the infants were observed for growth failure. The characteristics of 15 families with infants who developed NFT were compared with those of 86 selected randomly from the remaining families. Interview results suggest that NFT correlates significantly with aberrant nurture during the mother's childhood and with conflicts between the parents of the infants. Perinatal events correlating significantly with NFT include complications of pregnancy, short gestation, and residual minor medical problems at discharge from the nursery. We speculate that these events predispose to NFT by disturbing the development of the mother-infant relationship.

Propithecus verreauxi population and ranging at Berenty, Madagascar, 1975 and 1980

Propithecus verreauxi have been repeatedly censused in parts of the 200-ha reserve at Berenty between 1963 and 1975. Troop rearrangements in 1963 and 1975 showed that both males and females can change troop outside the breeding season. Group sex ratio varies from 0.3 female/male to 5.0 female/male. Usually, at Berenty, groups defend highly exclusive territories, in contrast to ranging patterns elsewhere. In 1980 troops were censused during 2 weeks in November at a different season from earlier studies. They had larger troop feeding dispersion than before, and pairs and triplets of males who travelled apart from bisexual troops. This may be a season of mass male migration, as in Lemur catta, or else a long-term population change. This small reserve should be carefully monitored as its lemurs have so far maintained relative population stability.

Population and troop ranges of Lemur catta and Lemur fulvus at Berenty, Madagascar: 1980 census

The November 1980 census suggests that population size and troop ranges have remained stable since 1972 and in a small area since 1963. This prolongs the apparent stability described by some authors, remarkable in a 200-ha reserve containing a maximum of 300 Lemur catta. However, inadvertent introduction of Lemur fulvus rufus and apparent loss of tamarind trees, as well as general genetic and biogeographic considerations, imply this stability may not continue. Berently underlines the need for long-term, widespread primate research and practical conversation.

Effect of resident peer review on charting behavior

Traditionally the medical profession and, more recently, federal agencies have promoted peer review to improve quality of health care, although its effectiveness is uncertain. To assess ability of peer review to increase recording of comprehensive care, the resident charting of growth, immunizations, and family, past medical, developmental, and birth history was monitored in randomly selected charts six months before (747 charts) and six months after institution of peer review (691 charts). Faculty emphasis for charting remained uniform throughout the study. During ten 1-hour sessions, pediatric residents reviewed the charts of their colleagues for comprehensive care and other measurements using a standard form. Although faculty were not present, residents reported by post-study interview that vigorous discussion and peer pressure occurred during the sessions, and subjectively they felt their charting had improved. An objective assessment indicated charting of past medical history worsened after peer review was initiated, and charting of family history improved slightly. All changes were marginal. Charting was not related to the volume of patients seen by individual residents or their level of training but was relatively consistent for individual residents over successive rotations.

Radiologic evaluation of the cerebellopontine cistern and the internal auditory canal

Radiologic evaluation of patients with unilateral sensorineural hearing loss depends on the quality of the computed tomographic (CT) scanner. Two scanners were evaluated in the present study: one utilizing thick collimation (10- and 13-mm sections) and the second utilizing thin collimation (1.5-mm sections). In both evaluations, intravenous contrast medium was used to exclude a cerebellopontine angle mass. If the cerebellopontine cistern is normal and there is clinical evidence of an intracanalicular lesion, air or metrizamide CT is used. When 10- and 13-mm sections are used, air provides the best contrast with overlapping sections. When 1.5-mm sections are used, coronal CT shows metrizamide in the internal auditory canal.