Evaluation of a non-auditory neurocognitive test battery in hearing-impaired according to age

PURPOSE

Due to the demographic shift, the number of older people suffering from hearing loss and from cognitive impairment increases. Both are closely related and hard to differentiate as most standard cognitive test batteries are auditory-based and hearing-impaired individuals perform worse also in non-auditory test batteries. Therefore, reference data for hearing-impaired are mandatory.

METHODS

The computer-based battery ALAcog assesses multiple cognitive domains, such as attention, (delayed) memory, working memory, inhibition, processing speed, mental flexibility and verbal fluency. A data set of 201 bilaterally hearing-impaired subjects aged ≥ 50 (mean 66.6 (SD 9.07)) was analysed. The LMS method, estimated curves for the 10th, 25th, 50th, 75th and 90th percentile were calculated, and classified according to age, starting from the age of 50.

RESULTS

Cognitive function shows a decline in all subtests as people age, except for verbal fluency, which remains almost stable over age. The greatest declines were seen in recall and delayed recall and in mental flexibility. Age and hearing ability did not correlate (p = 0.68). However, as people age, inter-subject variability of cognitive test results increases. This was especially the case for inhibition. Cognitive function was not correlated with hearing ability (each p ≥ 0.13).

CONCLUSION

The present results make an approach to establish reference data for a comprehensive non-auditory test battery in a large sample of elderly hearing-impaired people which can be used as a simple tool to better contextualise cognitive performance beyond mean and median scores.

Immune checkpoint therapy responders display early clonal expansion of tumor infiltrating lymphocytes

Immune checkpoint therapy (ICT) causes durable tumour responses in a subgroup of patients, but it is not well known how T cell receptor beta (TCRβ) repertoire dynamics contribute to the therapeutic response. Using murine models that exclude variation in host genetics, environmental factors and tumour mutation burden, limiting variation between animals to naturally diverse TCRβ repertoires, we applied TCRseq, single cell RNAseq and flow cytometry to study TCRβ repertoire dynamics in ICT responders and non-responders. Increased oligoclonal expansion of TCRβ clonotypes was observed in responding tumours. Machine learning identified TCRβ CDR3 signatures unique to each tumour model, and signatures associated with ICT response at various timepoints before or during ICT. Clonally expanded CD8+ T cells in responding tumours post ICT displayed effector T cell gene signatures and phenotype. An early burst of clonal expansion during ICT is associated with response, and we report unique dynamics in TCRβ signatures associated with ICT response.

Health measurement instruments and their applicability to military veterans: a systematic review

INTRODUCTION

Accurate measurement of health status is essential to assess veterans' needs and the effects of interventions directed at improving veterans' well-being. We conducted a systematic review to identify instruments that measure subjective health status, considering four components (ie, physical, mental, social or spiritual well-being).

METHODS

Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses, we searched CINAHL, MEDLINE, Embase, PsycINFO, Web of Science, JSTOR, ERIC, Social Sciences Abstracts and ProQuest in June 2021 for studies reporting on the development or evaluation of instruments measuring subjective health among outpatient populations. We assessed risk of bias with the Consensus-based Standards for the Selection of Health Measurement Instruments tool and engaged three veteran partners to independently assess the clarity and applicability of identified instruments.

RESULTS

Of 5863 abstracts screened, we identified 45 eligible articles that reported health-related instruments in the following categories: general health (n=19), mental health (n=7), physical health (n=8), social health (n=3) and spiritual health (n=8). We found evidence for adequate internal consistency for 39 instruments (87%) and good test-retest reliability for 24 (53%) instruments. Of these, our veteran partners identified five instruments for the measurement of subjective health (Military to Civilian Questionnaire (M2C-Q), Veterans RAND 36-Item Health Survey (VR-36), Short Form 36, Abbreviated World Health Organization Quality of Life questionnaire (WHOQOL-BREF) and Sleep Health Scale) as clear and very applicable to veterans. Of the two instruments developed and validated among veterans, the 16-item M2C-Q considered most components of health (mental, social and spiritual). Of the three instruments not validated among veterans, only the 26-item WHOQOL-BREF considered all four components of health.

CONCLUSION

We identified 45 health measurement instruments of which, among those reporting adequate psychometric properties and endorsed by our veteran partners, 2 instruments showed the most promise for measurement of subjective health. The M2C-Q, which requires augmentation to capture physical health (eg, the physical component score of the VR-36), and the WHOQOL-BREF, which requires validation among veterans.

Patterns of coronary vascular involvement in patients with heart failure due to cardiac amyloidosis

Background

Amyloidosis is a group of protein-folding disorders characterised by organ deposits, derived from one of several amyloidogenic precursor proteins. The involvement of coronary arteries has been previously described in amyloidosis, however the pattern of the disease in the coronaries is still unknown.

Purpose

The aim of this study is to characterise the pattern and severity of coronary artery lesions in cardiac amyloidosis.

Methods

We retrospectively compared patients with heart failure who tested positive (i.e. biopsy or gene tests – HF/CA+) against those that tested negative (HF/CA−) for cardiac amyloidosis. Groups were compared demographically and angiographically for qualitative and quantitative variables to determine patterns of involvement in the major epicardial coronary vessels.

Results

In total, 110 heart failure patients were included in the study, of whom 55 were HF/CA+ patients (88 lesions) and 55 were HF/CA− patients (66 lesions). Despite the advanced age in the HF/CA+, (74.53±11.02 vs 54.11±15.08; p=0.05), severe calcification was reported in HF/CA− group (4.5% vs to 0.0%; p=0.018). The HF/CA+ group also had fewer ostial lesions (3.4% vs. 15.15%, p=0.0095), reduced TIMI flow grade (83% vs 76%; p=0.21) and a higher TIMI frame count (30±12 Vs 27±11 frames; p=0.06). In the HF/CA+ group, compared to women, men had a significant number of tandem lesions (14.55% vs 0.0%, p=0.02). Men trended to have more ulcerations in comparison to women (9.09% vs 0.0%; p=0.15).

Conclusion

Overall, patients with HF/CA+ were older but found to have lesser calcified lesions, ostial involvement and a reduced anterograde blood flow. This is the first report outlining the coronary lesions in patients with HF/CA+.

Funding Acknowledgement

Type of funding source: None

Nonlinear 3D projection printing of concave hydrogel microstructures for long-term multicellular spheroid and embryoid body culture

Long-term culture and monitoring of individual multicellular spheroids and embryoid bodies (EBs) remains a challenge for in vitro cell propagation. Here, we used a continuous 3D projection printing approach - with an important modification of nonlinear exposure - to generate concave hydrogel microstructures that permit spheroid growth and long-term maintenance, without the need for spheroid transfer. Breast cancer spheroids grown to 10 d in the concave structures showed hypoxic cores and signs of necrosis using immunofluorescent and histochemical staining, key features of the tumor microenvironment in vivo. EBs consisting of induced pluripotent stem cells (iPSCs) grown on the hydrogels demonstrated narrow size distribution and undifferentiated markers at 3 d, followed by signs of differentiation by the presence of cavities and staining of the three germ layers at 10 d. These findings demonstrate a new method for long-term (e.g. beyond spheroid formation at day 2, and with media exchange) 3D cell culture that should be able to assist in cancer spheroid studies as well as embryogenesis and patient-derived disease modeling with iPSC EBs.

Oculoleptomeningeal Amyloidosis associated with transthyretin Leu12Pro in an African patient

Oculoleptomeningeal amyloidosis is a rare manifestation of hereditary transthyretin (TTR) amyloidosis. Here, we present the first case of leptomeningeal amyloidosis associated with the TTR variant Leu12Pro mutation in an African patient. A 43-year-old right-handed Nigerian man was referred to our centre with rapidly progressive neurological decline. He presented initially with weight loss, confusion, fatigue, and urinary and erectile dysfunction. He then suffered recurrent episodes of slurred speech with right-sided weakness. He went on to develop hearing difficulties and painless paraesthesia. Neurological examination revealed horizontal gaze-evoked nystagmus, brisk jaw jerk, increased tone, brisk reflexes throughout and bilateral heel-shin ataxia. Magnetic resonance imaging showed extensive leptomeningeal enhancement. Cerebrospinal fluid analysis showed a raised protein of 6.4 g/dl. Nerve conduction studies showed an axonal neuropathy. Echocardiography was characteristic of cardiac amyloid. TTR gene sequencing showed that he was heterozygous for the leucine 12 proline mutation. Meningeal and brain biopsy confirmed widespread amyloid angiopathy. TTR amyloidosis is a rare cause of leptomeningeal enhancement, but should be considered if there is evidence of peripheral or autonomic neuropathy with cardiac or ocular involvement. The relationship between different TTR mutations and clinical phenotype, disease course, and response to treatment remains unclear.

Distinct and overlapping genomic profiles and antiviral effects of Interferon-λ and -α on HCV-infected and noninfected hepatoma cells

Recently, several SNPs in the region of the IL28B (IFN-λ) gene have been associated with spontaneous clearance of hepatitis C virus (HCV) and enhanced cure rates for IFN-alfa-based therapies, suggesting a potential correlation between IFN-λ and the ability to clear HCV. To understand the mechanism of IFN-λ's as compared to IFN-α's antiviral activity, we performed a comprehensive analysis of their anti-HCV effects, whole genome transcriptome profiling with validation, and signalling of IFN-α and IFN-λ using J6/JFH-1 and Huh7.5 cells in vitro. IFN-λ and IFN-α exhibited comparable anti-HCV activity and gene expression profiles in Huh7.5 cells. While the majority of genes induced by IFN-α and IFN-λ were similar, IFN-λ exhibits profound, but delayed kinetics of IFN-stimulated genes (ISG) induction, while IFN-α induced more rapid induction of ISGs. Furthermore, the increased induction of ISG expression by IFN-λ correlated with up-regulation of IFN-λ receptor (IL-28RA) expression and more prolonged activation of the Jak-STAT signalling pathway. The findings from our comparative analysis of IFN-α and IFN-λ in HCV-infected and noninfected cells support the clinical use of IFN-λ as a potential alternative to IFN-α in the treatment of chronic hepatitis C.

An adolescent athlete with groin and hip pain

The case report is presented of a 14-year-old boy with persistent right hip and groin pain. After failing to respond to conventional management, the patient was admitted and investigated. He had a fever and raised inflammatory markers. MRI of the pelvis revealed pyomyositis of the right adductor compartment extending into the pelvis. Pyomyositis should be considered in a patient with pain disproportionate to the physical examination findings.

Transforming growth factor- as a differentiating factor for cultured smooth muscle cells

The aim of the present study was to determine whether the development of supercontractile smooth muscle cells, contributing to the nonspecific hyperreactivity of airways in asthmatic patients, is due to transforming growth factor (TGF)-beta. In cultured smooth muscle cells starved by removal of 10% foetal bovine serum for 7 days, growth arrest was seen; 30% became elongated and demonstrated super contractility. Study of conditioned medium suggested that the differentiating factor was TGF-beta. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) was carried out on conditioned medium from the arrested cells. Two protein bands were identified as matrix metalloproteinase (MMP)-2 and TGF-beta1. To determine second messenger signalling by SMAD2, Western blotting and confocal microscopy were employed. Conditioned medium from arrested cultures showed the presence of MMP-2 and TGF-beta1, as revealed by SDS-PAGE; 68- and 25-kDa bands were seen. Differentiation was confirmed by upregulation of marker proteins, smooth muscle type myosin heavy chain and myosin light chain kinase. Confirmation was obtained by downregulating these proteins with decorin treatment, which reduces the levels of active TGF-beta and an adenoviral dominant-negative vector coding for a mutated type II TGF-beta-receptor. Activation of second messenger signalling was demonstrated immunocytochemically by the presence of phosphorylated SMAD2 and SMAD4. Transforming growth factor-beta is likely to be the differentiating factor responsible for the development of these supercontractile smooth muscle cells. The development of such cells in vivo after cessation of an asthmatic attack could contribute to the nonspecific hyperreactivity of airways seen in patients.

Suppressor of cytokine signaling-1 is an IL-4-inducible gene in macrophages and feedback inhibits IL-4 signaling

Interferon-gamma and interleukin-4 (IL-4) induce distinct gene expression profiles in macrophages by differentially activating signal transducers and activators of transcription (STAT)1 and STAT6, respectively. The role of suppressor of cytokine signaling (SOCS)-1 as a negative regulator of IFN-gamma signaling is well established. However, its potential role as a negative regulator of IL-4 signaling has not been explored. We found that IL-4, like IFN-gamma, induces rapid de novo expression of SOCS-1 in primary macrophages. Induction of SOCS-1 gene expression by IL-4 is STAT6-dependent, whereas induction of SOCS-1 by IFN-gamma is STAT1-dependent. Unlike their common ability to induce expression of SOCS-1, IL-4 also induced expression of SOCS-2 but not SOCS-3 in macrophages, whereas IFN-gamma induced expression of SOCS-3 but not SOCS-2. Forced expression of SOCS-1 or SOCS-3, but not SOCS-2, inhibited activation of STAT6 by IL-4. Moreover, SOCS-1 appears to serve as an endogenous regulator of IL-4 signaling in macrophages because the magnitude and duration of STAT6 activation as well as IL-4-mediated gene expression were much greater in SOCS-1-deficient (SOCS-1(-/-)) macrophages than in wild-type macrophages. Our findings demonstrate that, like IFN-gamma, IL-4 also induces expression of SOCS-1 in macrophages, and SOCS-1 feedback inhibits expression of STAT6-responsive genes.

Overexpression of FGF-2 increases cardiac myocyte viability after injury in isolated mouse hearts

We generated transgenic (TG) mice overexpressing fibroblast growth factor (FGF)-2 protein (22- to 34-fold) in the heart. Chronic FGF-2 overexpression revealed no significant effect on heart weight-to-body weight ratio or expression of cardiac differentiation markers. There was, however, a significant 20% increase in capillary density. Although there was no change in FGF receptor-1 expression, relative levels of phosphorylated c-Jun NH(2)-terminal kinase and p38 kinase as well as of membrane-associated protein kinase C (PKC)-alpha and total PKC-epsilon were increased in FGF-2-TG mouse hearts. An isolated mouse heart model of ischemia-reperfusion injury was used to assess the potential of increased endogenous FGF-2 for cardioprotection. A significant 34-45% increase in myocyte viability, reflected in a decrease in lactate dehydrogenase released into the perfusate, was observed in FGF-2 overexpressing mice and non-TG mice treated exogenously with FGF-2. In conclusion, FGF-2 overexpression causes augmentation of signal transduction pathways and increased resistance to ischemic injury. Thus, stimulation of endogenous FGF-2 expression offers a potential mechanism to enhance cardioprotection.

Role for early growth response-1 protein in alpha(1)-adrenergic stimulation of fibroblast growth factor-2 promoter activity in cardiac myocytes

Fibroblast growth factor-2 (FGF-2), a mitogenic, angiogenic, and cardioprotective agent, is released from the postnatal heart by a mechanism of transient remodelling of the sarcolemma during contraction. Both release of FGF-2 and its synthesis can be increased with adrenergic stimulation. We reported previously that FGF-2 synthesis can be regulated at the transcriptional level by alpha-adrenergic stimulation of cultured neonatal rat cardiac myocytes as well as in the adult mouse heart. Examination of the proximal promoter region of both human and rat FGF-2 gene sequences revealed binding sites for the early growth response-1 (Egr-1) protein. Using gel mobility shift assays, we observed a transient increase in a complex between nuclear extracts from neonatal rat cardiac myocytes treated with inducers of Egr-1, including the alpha-adrenergic agonist phenylephrine, angiotensin II, and phorbol ester, and a consensus Egr-1 DNA element. A similar complex was seen with the FGF-2 promoter region -7/+42 as the DNA probe, but not when the Egr-1 element at nucleotides +3/+31 was disrupted. Participation of Egr-1 protein in the complex was confirmed by competition with Egr-1 DNA elements and antibodies. With deletion analysis and transfection of neonatal rat cardiac myocytes, the alpha-adrenergic response was localized to nucleotides -110/+42 of the FGF-2 gene in the context of a hybrid FGF-2/luciferase reporter gene, -110FGFp.luc. Overexpression of Egr-1 increased -110FGFp.luc gene expression, whereas mutation of its Egr-1 element at nucleotides +3/+31 abolished alpha-adrenergic responsiveness. These data indicate that Egr-1 is involved in the alpha-adrenergic stimulation of the FGF-2 promoter region in neonatal cardiac myocytes.

Overexpression of long or short FGFR-1 results in FGF-2-mediated proliferation in neonatal cardiac myocyte cultures

OBJECTIVE

The type 1 fibroblast growth factor receptor (FGFR-1) is the only high affinity receptor for fibroblast growth factor-2 (FGF-2) in the rat myocardium, and is essential for normal growth and development of the heart. Levels of FGFR-1 are developmentally regulated, being high in embryonic cardiac myocytes. Also, FGFR-1 exists as both 'long' and 'short' isoforms, and there is a switch from predominant expression of the 'long' isoform in the embryo to the 'short' isoform in the adult heart. Both the decrease in receptor levels and the isoform switch in postnatal cardiac myocytes correlate with a loss of proliferative potential. We investigated whether an increase in either 'long' or 'short' FGFR-1 isoforms could stimulate proliferation in postnatal rat cardiac myocyte cultures.

METHODS AND RESULTS

Previously we cloned cDNAs corresponding to 'long' (L) and 'short' (S) FGFR-1 isoforms from embryonic mouse hearts. Hybrid FGFR-1(L) and (S) genes, directed by a myosin light chain-2 promoter and SV40 enhancer sequences, were generated and used to transiently transfect neonatal rat cardiac myocytes. Overexpression of FGFR-1 mRNA and protein was detected by RNA blotting and immunocytochemistry. Ligand-crosslinking confirmed the presence of specific receptors capable of binding FGF-2 on the cell membrane. Overexpression of either FGFR-1(L) or (S) was associated with stimulation of proliferation as assessed by significant increases in bromodeoxyuridine uptake (DNA synthesis) and cell number. To determine whether this response was FGF-2 specific, the level of FGF-2 was assessed in the culture medium of cardiac myocytes overexpressing FGFR-1 isoforms. A three-fold increase was detected in the media of cardiac myocytes overexpressing either FGFR-1(L) or (S) compared to control levels. Neutralization of this FGF-2 with antibodies inhibited the proliferative response.

CONCLUSION

Overexpression of either FGFR-1(L) or (S) resulted in an increase in FGF-2-mediated proliferation of postnatal rat cardiac myocytes.

Detection of 28S RNA with the FGF-2 cDNA at high stringency through related G/C-rich sequences

Fibroblast growth factor-2 (FGF-2) or basic FGF is a multifunctional protein that, through interaction with specific cell surface receptors, plays important roles in the growth and development of tissues and organs. Thus, considerable attention has focused on the control of FGF-2 gene expression, including assessments of RNA levels through blotting and the use of radiolabeled FGF-2 cDNA probes. Multiple transcripts of different sizes have been reported for FGF-2 by this approach, however, more recent evidence indicates that at least one of these RNAs of about 1.5 kb, is not an authentic FGF-2 transcript. A major band of 4.7 kb and a minor band of 6.1 kb were detected in total rat glial tumor cell RNA, using the 'intact' rat ovarian FGF-2 cDNA as a probe at high stringency. This cDNA contains both coding and 5'-untranslated sequences. Although the 6.1 kb transcript levels were increased in RNA enriched for polyadenylated species, the levels of the 4.7 kb band were decreased and also shared a mobility with 28S RNA. A truncated FGF-2 cDNA probe, containing coding but not 5'-untranslated sequences, detected the 6.1 kb transcript but failed to see the 4.7 kb band. The domain responsible for detecting the 4.7 kb band was localized to a G/C-rich region containing 5'-untranslated sequences, by using different fragments of the rat FGF-2 gene, including coding and upstream flanking DNA, as probes. The degree of similarity between sequences of this G/C-rich region of the FGF-2 gene and 28S RNA from rat, human and mouse was sufficient to predict strong cross hybridization. This was confirmed by the detection of a 4.7 kb band in mouse heart RNA with the 'intact' but not truncated rat FGF-2 cDNA probes; a 6.1 kb mouse FGF-2 transcript was detected with both probes. These data indicate that the 4.7 kb RNA detected is not a bona fide FGF-2 transcript, and most likely represents cross hybridization with abundant 28S RNA through G/C-rich non-coding sequences present in the 'intact' rat FGF-2 cDNA. However, sequence comparisons suggest that this result may be the case for other species and might not be restricted to the rat FGF-2 cDNA.

Expression of fibroblast growth factor receptor-1 in rat heart H9c2 myoblasts increases cell proliferation

Basic fibroblast growth factor (FGF-2) plays an important role in myocardial growth and development and in particular cardiac myocyte proliferation. FGF-2 exerts its effects by binding to cell surface receptors (FGFR-1) of the tyrosine kinase family. We have detected the presence of both long and short isoforms of FGFR-1 in embryonic and adult mouse heart. In this report, we have examined the ability of long and short FGFR-1 isoforms to signal a mitogenic response. Assessment of RNA from rat myoblast H9c2 cells by reverse transcriptase-polymerase chain reaction and RNA blotting revealed that they were deficient in transcripts corresponding to long and short FGFR-1 species. Hybrid genes containing the cDNAs coding for long and short FGFR-1 isoforms directed by the myosin light chain-2 promoter and simian virus 40 enhancer sequences, were used to transiently transfect H9c2 cells. Total tyrosine phosphorylation was increased 2.0 and 2.6 fold in H9c2 cells transfected with the long and short FGFR-1 isoforms, respectively, compared to 'control' transfected H9c2 cells. This was accompanied by a 2.1 and 2.0 fold increase in DNA synthesis, as measured by tritiated thymidine incorporation, in H9c2 cells expressing the long and short FGFR-1 isoforms, respectively. To assess effects on proliferation, H9c2 cells were stably transfected with the myosin light chain-2/FGFR-1 cDNA genes. The rate of proliferation was increased 1.6 and 3.1 fold in H9c2 cells stably expressing the long and short FGFR-1 isoforms, respectively, compared to 'control' H9c2 cells. In contrast to non transfected H9c2 cells, treatment of H9c2 cells stably expressing long FGFR-1 with FGF-2 for 24 h resulted in a slight increase (1.3 fold, p < 0.02) in cell number. However, a greater response (1.5 fold, p < 0.0005) was observed with H9c2 cells stably expressing short FGFR-1 after treatment with FGF-2. These results suggest that both long and short FGFR-1 isoforms are capable of signalling a mitogenic response.

Cluster of wound botulism in California: clinical, electrophysiologic, and pathologic study

Over a period of 15 months we have seen 6 patients with long-standing history of subcutaneous heroin injections who experienced acute blurred vision, dysphagia, dysarthria, and generalized weakness. Decreased or absent deep tendon reflexes, pupillary abnormalities, incremental responses to fast repetitive nerve stimulation, and positive serology for Clostridia botulinum toxin A were found, but not in all cases. Muscle biopsies showed variable signs of neurogenic atrophy. In vitro electrophysiology studies revealed decreased end-plate potentials quantal content, confirming the presynaptic nature of the disorder. Mechanical ventilation was required in 5 patients. Half of the patients were treated with polyvalent antitoxiin. Prognosis was favorable, though recovery was slow. In conclusion, acute bulbar weakness with visual symptoms in patients with subcutaneous heroin abuse strongly suggets the possibility of wound botulism. High diagnostic suspicion combined with histology and in vitro electrophysiology confirmation of presynaptic failure, especially in seronegative cases, may significantly improve morbidity.

Topology of ATP-binding domain of adrenoleukodystrophy gene product in peroxisomes

Adrenoleukodystrophy (X-ALD) is a demyelinating disorder characterized by the accumulation of saturated very-long-chain fatty acids (> C22:0) due to the impaired activity of lignoceroyl-CoA ligase. The gene responsible for the disease was found to code for a 84-kDa peroxisomal integral membrane protein. Its amino acid sequence has high homology with the ATP-binding cassette superfamily of transporters and it is predicted to have six membrane-spanning segments and a putative ATP-binding domain. To define the function of ALDP, we studied the topology of its ATP-binding domain by using antibodies (1D6) against a hydrophobic domain (amino acid residues 279 to 482) and antibodies (Abct) against the C-terminal 15-amino-acid hydrophilic domain (amino acid residues 731 to 745) of ALDP. The observation of punctate fluorescence in permeabilized ALD fibroblasts, using Abct antibodies but not with antibodies against catalase, suggests that the C-terminal segment of ALDP is projected toward the cytoplasm from the peroxisomal membrane. Trypsinization of intact peroxisomes under isotonic conditions abolishes the Abct antibody recognition site, whereas the 1D6 antibodies identify a degradation product of 43-kDa protein that has been protected and retained by the membrane. This again suggests that the C-terminal portion of the ALDP protein is located on the outside (cytoplasmic) face of the peroxisomal membrane. Additional support for this conclusion was obtained by purification of the ALDP C-terminal domain, released from purified rat liver peroxisomes incubated with the cytosolic fraction, using blue-Sepharose affinity chromatography. A 47-kDa peptide retained by the column was recognized by Western blot analysis with Abct antibodies against the C-terminal sequence of ALDP and this polypeptide on polyvinylidene difluoride membrane was able to bind [gamma-32P]ATP in vitro in the presence of Mg2+. These results demonstrate that the C-terminal peptide containing the ATP-binding domains of ALDP is on the cytoplasmic surface of the peroxisomal membrane where this domain may function as an ATPase to support the functional role of ALDP in the peroxisomal membrane.

Is anorectal surgery on chronic dialysis patients risky?

Patients on chronic hemodialysis for end-stage renal disease (ESRD) may develop anorectal problems necessitating surgery. From January 1984 to December 1987, 18 ESRD patients underwent anorectal surgery. During this period, a mean of 215 patients underwent dialysis. Patients with ESRD present with characteristic problems: chronic constipation, need for dialysis pre- and postoperatively with heparin infusion, anemia, anticoagulation secondary to the consequences of uremia, and significant medical problems including coronary artery disease, diabetes mellitus, hypertension, and chronic obstructive pulmonary disease (COPD). Two patients had concomitant anal fissure, two had fistula-in-ano, and one had an acute perianal abscess. In two patients, the postoperative course was complicated by hemorrhage and, in one patient, by abscess formation. There was no delay in wound healing compared with a cohort group. The essentials of perioperative management are discussed with respect to timing of dialysis, methods of anesthesia and pain management, coagulation screening, and complications. Patients on well-managed chronic dialysis will tolerate anorectal surgery without undue jeopardy.