The right ventricular transcriptome signature in Ossabaw swine with cardiometabolic heart failure: implications for the coronary vasculature

Heart failure (HF) patients with deteriorating right ventricular (RV) structure and function have a nearly twofold increased risk of death compared with those without. Despite the well-established clinical risk, few studies have examined the molecular signature associated with this HF condition. The purpose of this study was to integrate morphological, molecular, and functional data with the transcriptome data set in the RV of a preclinical model of cardiometabolic HF. Ossabaw swine were fed either normal diet without surgery (lean control, n = 5) or Western diet and aortic-banding (WD-AB; n = 4). Postmortem RV weight was increased and positively correlated with lung weight in the WD-AB group compared with CON. Total RNA-seq was performed and gene expression profiles were compared and analyzed using principal component analysis, weighted gene co-expression network analysis, module enrichment analysis, and ingenuity pathway analysis. Gene networks specifically associated with RV hypertrophic remodeling identified a hub gene in MAPK8 (or JNK1) that was associated with the selective induction of the extracellular matrix (ECM) component fibronectin. JNK1 and fibronectin protein were increased in the right coronary artery (RCA) of WD-AB animals and associated with a decrease in matrix metalloproteinase 14 protein, which specifically degrades fibronectin. RCA fibronectin content was correlated with increased vascular stiffness evident as a decreased elastin elastic modulus in WD-AB animals. In conclusion, this study establishes a molecular and transcriptome signature in the RV using Ossabaw swine with cardiometabolic HF. This signature was associated with altered ECM regulation and increased vascular stiffness in the RCA, with selective dysregulation of fibronectin.

Western Diet-Fed, Aortic-Banded Ossabaw Swine: A Preclinical Model of Cardio-Metabolic Heart Failure

The development of new treatments for heart failure lack animal models that encompass the increasingly heterogeneous disease profile of this patient population. This report provides evidence supporting the hypothesis that Western Diet-fed, aortic-banded Ossabaw swine display an integrated physiological, morphological, and genetic phenotype evocative of cardio-metabolic heart failure. This new preclinical animal model displays a distinctive constellation of findings that are conceivably useful to extending the understanding of how pre-existing cardio-metabolic syndrome can contribute to developing HF.

Increased endothelial shear stress improves insulin-stimulated vasodilatation in skeletal muscle

KEY POINTS

It has been postulated that increased blood flow-associated shear stress on endothelial cells is an underlying mechanism by which physical activity enhances insulin-stimulated vasodilatation. This report provides evidence supporting the hypothesis that increased shear stress exerts insulin-sensitizing effects in the vasculature and this evidence is based on experiments in vitro in endothelial cells, ex vivo in isolated arterioles and in vivo in humans. Given the recognition that vascular insulin signalling, and associated enhanced microvascular perfusion, contributes to glycaemic control and maintenance of vascular health, strategies that stimulate an increase in limb blood flow and shear stress have the potential to have profound metabolic and vascular benefits mediated by improvements in endothelial insulin sensitivity.

ABSTRACT

The vasodilator actions of insulin contribute to glucose uptake by skeletal muscle, and previous studies have demonstrated that acute and chronic physical activity improves insulin-stimulated vasodilatation and glucose uptake. Because this effect of exercise primarily manifests in vascular beds highly perfused during exercise, it has been postulated that increased blood flow-associated shear stress on endothelial cells is an underlying mechanism by which physical activity enhances insulin-stimulated vasodilatation. Accordingly, herein we tested the hypothesis that increased shear stress, in the absence of muscle contraction, can acutely render the vascular endothelium more insulin-responsive. To test this hypothesis, complementary experiments were conducted using (1) cultured endothelial cells, (2) isolated and pressurized skeletal muscle arterioles from swine, and (3) humans. In cultured endothelial cells, 1 h of increased shear stress from 3 to 20 dynes cm^-2 caused a significant shift in insulin signalling characterized by greater activation of eNOS relative to MAPK. Similarly, isolated arterioles exposed to 1 h of intraluminal shear stress (20 dynes cm^-2 ) subsequently exhibited greater insulin-induced vasodilatation compared to arterioles kept under no-flow conditions. Finally, we found in humans that increased leg blood flow induced by unilateral limb heating for 1 h subsequently augmented insulin-stimulated popliteal artery blood flow and muscle perfusion. In aggregate, these findings across models (cells, isolated arterioles and humans) support the hypothesis that elevated shear stress causes the vascular endothelium to become more insulin-responsive and thus are consistent with the notion that shear stress may be a principal mechanism by which physical activity enhances insulin-stimulated vasodilatation.

Chronic interval exercise training prevents BKCa channel-mediated coronary vascular dysfunction in aortic-banded miniswine

Conventional treatments have failed to improve the prognosis of heart failure with preserved ejection fraction (HFpEF) patients. Thus, the purpose of this study was to determine the therapeutic efficacy of chronic interval exercise training (IT) on large-conductance Ca²⁺-activated K⁺ (BK_Ca) channel-mediated coronary vascular function in heart failure. We hypothesized that chronic interval exercise training would attenuate pressure overload-induced impairments to coronary BK_Ca channel-mediated function. A translational large-animal model with cardiac features of HFpEF was used to test this hypothesis. Specifically, male Yucatan miniswine were divided into three groups ( n = 7/group): control (CON), aortic banded (AB)-heart failure (HF), and AB-interval trained (HF-IT). Coronary blood flow, vascular conductance, and vasodilatory capacity were measured after administration of the BK_Ca channel agonist NS-1619 both in vivo and in vitro in the left anterior descending coronary artery and isolated coronary arterioles, respectively. Skeletal muscle citrate synthase activity was decreased and left ventricular brain natriuretic peptide levels increased in HF vs. CON and HF-IT animals. A parallel decrease in NS-1619-dependent coronary vasodilatory reserve in vivo and isolated coronary arteriole vasodilatory responsiveness in vitro were observed in HF animals compared with CON, which was prevented in the HF-IT group. Although exercise training prevented BK_Ca channel-mediated coronary vascular dysfunction, it did not change BK_Ca channel α-subunit mRNA, protein, or cellular location (i.e., membrane vs. cytoplasm). In conclusion, these results demonstrate the viability of chronic interval exercise training as a therapy for central and peripheral adaptations of experimental heart failure, including BK_Ca channel-mediated coronary vascular dysfunction. NEW & NOTEWORTHY Conventional treatments have failed to improve the prognosis of heart failure with preserved ejection fraction (HFpEF) patients. Our findings show that chronic interval exercise training can prevent BK_Ca channel-mediated coronary vascular dysfunction in a translational swine model of chronic pressure overload-induced heart failure with relevance to human HFpEF.

Endothelial dysfunction occurs independently of adipose tissue inflammation and insulin resistance in ovariectomized Yucatan miniature-swine

In rodents, experimentally-induced ovarian hormone deficiency increases adiposity and adipose tissue (AT) inflammation, which is thought to contribute to insulin resistance and increased cardiovascular disease risk. However, whether this occurs in a translationally-relevant large animal model remains unknown. Herein, we tested the hypothesis that ovariectomy would promote visceral and perivascular AT (PVAT) inflammation, as well as subsequent insulin resistance and peripheral vascular dysfunction in female swine. At sexual maturity (7 months of age), female Yucatan mini-swine either remained intact (control, n = 9) or were ovariectomized (OVX, n = 7). All pigs were fed standard chow (15-20 g/kg), and were euthanized 6 months post-surgery. Uterine mass and plasma estradiol levels were decreased by ∼10-fold and 2-fold, respectively, in OVX compared to control pigs. Body mass, glucose homeostasis, and markers of insulin resistance were not different between control and OVX pigs; however, OVX animals exhibited greater plasma triglycerides and triglyceride:HDL ratio. Ovariectomy enhanced visceral adipocyte expansion, although this was not accompanied by brachial artery PVAT adipocyte expansion, AT inflammation in either depot, or increased systemic inflammation assessed by plasma C-reactive protein concentrations. Despite the lack of AT inflammation and insulin resistance, OVX pigs exhibited depressed brachial artery endothelial-dependent vasorelaxation, which was rescued with blockade of endothelin receptor A. Together, these findings indicate that in female Yucatan mini-swine, increased AT inflammation and insulin resistance are not required for loss of ovarian hormones to induce endothelial dysfunction.

Loss of Female Sex Hormones Exacerbates Cerebrovascular and Cognitive Dysfunction in Aortic Banded Miniswine Through a Neuropeptide Y-Ca2+-Activated Potassium Channel-Nitric Oxide Mediated Mechanism

Background

Postmenopausal women represent the largest cohort of patients with heart failure with preserved ejection fraction, and vascular dementia represents the most common form of dementia in patients with heart failure with preserved ejection fraction. Therefore, we tested the hypotheses that the combination of cardiac pressure overload (aortic banding [AB]) and the loss of female sex hormones (ovariectomy [OVX]) impairs cerebrovascular control and spatial memory.

Methods and Results

Female Yucatan miniswine were separated into 4 groups (n=7 per group): (1) control, (2) AB, (3) OVX, and (4) AB‐OVX. Pigs underwent OVX and AB at 7 and 8 months of age, respectively. At 14 months, cerebral blood flow velocity and spatial memory (spatial hole‐board task) were lower in the OVX groups (P<0.05), with significant impairments in the AB‐OVX group (P<0.05). Resting carotid artery β stiffness and vascular resistance during central hypovolemia were increased in the AB‐OVX group (P<0.05), and blood flow recovery after central hypovolemia was reduced in both OVX groups (P<0.05). Isolated pial artery (pressure myography) vasoconstriction to neuropeptide Y was greatest in the AB‐OVX group (P<0.05), and vasodilation to the Ca²⁺‐activated potassium channel α‐subunit agonist NS‐1619 was impaired in both AB groups (P<0.05). The ratio of phosphorylated endothelial nitric oxide synthase:total endothelial nitric oxide synthase was depressed and Ca²⁺‐activated potassium channel α‐subunit protein was increased in AB groups (P<0.05).

Conclusions

Mechanistically, impaired cerebral blood flow control in experimental heart failure may be the result of heightened neuropeptide Y–induced vasoconstriction along with reduced vasodilation associated with decreased Ca²⁺‐activated potassium channel function and impaired nitric oxide signaling, the effects of which are exacerbated in the absence of female sex hormones.

Abstract 87: Alterations to Cardiac Mechanics Do Not Preserve Normal Cardiac Function in a Novel Ossabaw Swine Model of Heart Failure with Preserved Ejection Fraction

Introduction: Heart failure with preserved ejection fraction (HFpEF) is clinically characterized by an increased incidence in females and many comorbidities including type 2 diabetes (T2D) and obesity. Animal models accurately representing clinical HFpEF are lacking; thus, the purpose of this study was to examine left ventricular (LV) mechanics in a novel Ossabaw swine model of chronic pressure-overload (aortic-banding; AB) and T2D (Western diet; WD) using two dimensional speckle tracking echocardiography (2D-STE). We hypothesized that global LV strain would be decreased primarily in the longitudinal direction in WD-AB animals.

Methods: Female Ossabaws were randomly divided into 2 groups: CON (n=5) and WD-AB (n=5). LV function and strain were measured at 1 year of age after 6 mo. of AB and 9 mo. of WD via pressure-volume relations and 2D-STE. Significance was set at P < 0.05 using t-test vs. CON.

Results: In the WD-AB group, ejection fraction (EF%) and end diastolic volume were normal (>50%), and observed in parallel with increased LV weight, lung weight, and LV diastolic wall thickness (i.e. concentric hypertrophy). WD-AB group had increased HOMA-IR and body surface area, two common features in T2D. In WD-AB animals, although global longitudinal systolic strain rate and end systolic displacement were increased, stroke volume index was decreased. Early diastolic rotation rate was decreased, while global longitudinal late diastolic strain rate was increased in the WD-AB group. These changes, considered in parallel with an increased end diastolic pressure-volume relationship in WD-AB animals, are consistent with diastolic dysfunction. In contrast, longitudinal, radial, and circumferential early diastolic strain rates increased in the WD-AB group.

Conclusion: Contrary to our hypothesis, LV longitudinal strain was increased during both systole and diastole, and observed in parallel with decreased early diastolic untwisting in WD-AB animals. Our results suggest alterations to LV mechanics do not preserve normal systolic and diastolic cardiac function, despite normal resting EF%, in this novel translational model of pressure-overload HF with potential relevance to human HFpEF including associated clinical comorbidities (sex, obesity, and T2D).

The protective role of sex hormones in females and exercise prehabilitation in males on sternotomy-induced cranial hypoperfusion in aortic banded mini-swine

During cardiac surgery, specifically sternotomy, cranial hypoperfusion is linked to cerebral ischemia, increased risk of perioperative watershed stroke, and other neurocognitive complications. The purpose of this study was to retrospectively examine the effect of sex hormones in females and exercise prehabilitation in males on median sternotomy-induced changes in cranial perfusion in a large animal model of heart failure. Cranial blood flow (CBF) before and 10 and 60 min poststernotomy was analyzed in eight groups of Yucatan mini-swine: female control, aortic banded, ovariectomized, and ovariectomized + aortic banded; male control, aortic banded, aortic banded + continuous exercise trained, and aortic banded + interval exercise trained. A median sternotomy decreased cranial perfusion during surgery in all pigs (~24 ± 2% relative to baseline; P ≤ 0.05). CBF was 30 ± 7% lower across all time points in all females vs. all males (P ≤ 0.05) and sternotomy decreased cranial perfusion (P ≤ 0.05) independent of sex (females = 34 ± 3% and males = 14 ± 3%) and aortic banding (intact control = 31 ± 5% and intact aortic banded = 31 ± 4%). CBF recovery at 60 min tended to be better in females vs. males (relative to 10 min poststernotomy, females = 23 ± 13% vs. males = -1 ± 5%) and intact aortic banded vs. control pigs (relative to 10 min poststernotomy, aortic banded = 43 ± 20% vs. control = 6 ± 16%; P ≤ 0.05) at 60 min poststernotomy. Ovariectomy impaired CBF recovery during cranial reperfusion 60 min following sternotomy (relative to baseline, all intact females = -1 ± 9% vs. all ovariectomized females = -15 ± 4%; P ≤ 0.05). Chronic exercise training completely prevented significant sternotomy-induced cranial hypoperfusion independent of aortic banding (sternotomy-induced deficit, all sedentary males = -24 ± 6% vs. all exercise-trained males = -7 ± 3%; P ≤ 0.05). Female sex hormones protected against impaired CBF recovery during reperfusion, while chronic exercise training prevented sternotomy-induced cranial hypoperfusion despite cardiac pressure overload.NEW & NOTEWORTHY Our findings suggest a median sternotomy may predispose patients, possibly postmenopausal women and sedentary men, to perioperative cerebral ischemia, an increased risk of cardiac surgery-related stroke, and resulting neurocognitive impairments. Specifically, data from this common surgical procedure show: 1) median sternotomy independently decreases cranial perfusion; 2) female sex hormones improve cranial blood flow recovery following sternotomy; and 3) exercise prehabilitation prevents sternotomy-induced cranial hypoperfusion. Exercise prehabilitation before cardiac surgery may be advantageous for capable patients.

Altered microstructure in temporal lobe epilepsy: a diffusional kurtosis imaging study

BACKGROUND AND PURPOSE

Temporal lobe epilepsy is associated with regional abnormalities in tissue microstructure, as demonstrated by DTI. However, the full extent of these abnormalities has not yet been defined because DTI conveys only a fraction of the information potentially accessible with diffusion MR imaging. In this study, we assessed the added value of diffusional kurtosis imaging, an extension of DTI, to evaluate microstructural abnormalities in patients with temporal lobe epilepsy.

MATERIALS AND METHODS

Thirty-two patients with left temporal lobe epilepsy and 36 matched healthy subjects underwent diffusion MR imaging. To evaluate abnormalities in patients, we performed voxelwise analyses, assessing DTI-derived mean diffusivity, fractional anisotropy, and diffusional kurtosis imaging-derived mean diffusional kurtosis, as well as diffusional kurtosis imaging and DTI-derived axial and radial components, comparing patients with controls.

RESULTS

We replicated findings from previous studies demonstrating a reduction in fractional anisotropy and an increase in mean diffusivity preferentially affecting, but not restricted to, the temporal lobe ipsilateral to seizure onset. We also noted a pronounced pattern of diffusional kurtosis imaging abnormalities in gray and white matter tissues, often extending into regions that were not detected as abnormal by DTI measures.

CONCLUSIONS

Diffusional kurtosis is a sensitive and complementary measure of microstructural compromise in patients with temporal lobe epilepsy. It provides additional information regarding the anatomic distribution and degree of damage in this condition. Diffusional kurtosis imaging may be used as a biomarker for disease severity, clinical phenotypes, and treatment monitoring in epilepsy.

Hippocampal tissue of patients with refractory temporal lobe epilepsy is associated with astrocyte activation, inflammation, and altered expression of channels and receptors

Temporal lobe epilepsy (TLE) is the most common form of focal epilepsy. Previous research has demonstrated several trends in human tissue that, undoubtedly, contribute to the development and progression of TLE. In this study we examined resected human hippocampus tissue for a variety of changes including gliosis that might contribute to the development and presentation of TLE. The study subjects consisted of six TLE patients and three sudden-death controls. Clinicopathological characteristics were evaluated by H&E staining. Immunohistological staining and Western blotting methods were used to analyze the samples. Neuronal hypertrophy was observed in resected epileptic tissue. Immunohistological staining demonstrated that activation of astrocytes was significantly increased in epileptic tissue as compared to corresponding regions of the control group. The Western blot data also showed increased CX43 and AQP4 in the hippocampus and downregulation of Kir4.1, α-syntrophin, and dystrophin, the key constituents of AQP4 multi-molecular complex. These tissues also demonstrated changes in inflammatory factors (COX-2, TGF-β, NF-κB) suggesting that these molecules may play an important role in TLE pathogenesis. In addition we detected increases in metabotropic glutamate receptor (mGluR) 2/3, mGluR5 and kainic acid receptor subunits KA1 (Grik4) and KA2 (Grik5) in patients' hippocampi. We noted increased expression of the α1c subunit comprising class C L-type Ca(2+) channels and calpain expression in these tissues, suggesting that these subunits might have an integral role in TLE pathogenesis. These changes found in the resected tissue suggest that they may contribute to TLE and that the kainic acid receptor (KAR) and deregulation of GluR2 receptor may play an important role in TLE development and disease course. This study identifies alterations in number of commonly studied molecular targets associated with astrogliosis, cellular hypertrophy, water homeostasis, inflammation, and modulation of excitatory neurotransmission in hippocampal tissues from TLE patients.

Hippocampal atrophy in temporal lobe epilepsy: the 'generator' and 'receiver'

OBJECTIVE

Some patients with unilateral medial temporal lobe epilepsy (MTLE) display bilateral hippocampal atrophy on MRI, even though seizures originate in only one hippocampus. The correct identification of the epileptogenic hippocampus (the 'generator') vs the non-epileptogenic (the 'receiver') may lead to better surgical planning and results.

MATERIALS AND METHODS

We studied 14 patients with MTLE (eight left and six right) who became seizure free after unilateral hippocampal resection, with hippocampal sclerosis confirmed by histology. Hippocampal tridimensional morphometry was performed comparing patients and healthy controls employing a voxel-wise Wilcoxon test. Results were corrected for multiple comparisons with the application of a False Discovery Rate (FDR)-corrected threshold for q < 0.05.

RESULTS

Patients with MTLE showed atrophy involving the ipsilateral hippocampus and the contralateral hippocampus, more pronouncedly within the ipsilateral hippocampus in the anterior-inferior aspect of the hippocampal head (left MTLE, left hippocampus x = -28, y = -16, z = -24, Z = 3.6; right MTLE, right hippocampus x = 22, y = -11, z = -27, Z = 2.9). On the contralateral hippocampus, the atrophy was more noticeable in the posterior head and body areas.

CONCLUSION

The epileptogenic hippocampal atrophy has an anatomically distinct pattern compared with the contralateral hippocampus. This information may help guide the presurgical assessment of MTLE.

Atypical prion protein in sheep brain collected during the British scrapie-surveillance programme

Scrapie of sheep and goats is the most common prion disease (or transmissible spongiform encephalopathy, TSE) of mammals and aggregates of abnormal, proteinase-resistant prion protein (PrPSc) are found in all naturally occurring prion diseases. During active surveillance of British sheep for TSEs, 29 201 sheep brain stem samples were collected from abattoirs and analysed for the presence of PrPSc. Of these samples, 54 were found to be positive by using an ELISA screening test, but 28 of these could not be confirmed initially by immunohistochemistry. These unconfirmed or atypical cases were generally found in PrP genotypes normally associated with relative resistance to clinical scrapie and further biochemical analysis revealed that they contained forms of PrPSc with a relatively protease-sensitive amyloid core, some resembling those of Nor98 scrapie. The presence of these atypical forms of protease-resistant PrP raises concerns that some TSE disorders of PrP metabolism previously may have escaped identification in the British sheep population.

B cell depletion therapy in systemic lupus erythematosus: Effect on autoantibody and antimicrobial antibody profiles

OBJECTIVE

Autoantibody production in patients with systemic lupus erythematosus (SLE) is associated with abnormalities of B cell function and phenotype. Clinical responses to B cell depletion therapy (BCDT), based on rituximab, are encouraging. Therefore, we undertook this study to investigate the effect of BCDT on antibody profiles.

METHODS

Serial sera from 16 patients with active, refractory SLE were assayed for antinucleosome antibodies, anti-double-stranded DNA (anti-dsDNA), anti-extractable nuclear antigen, anti-tetanus toxoid, and antibodies to pneumococcal capsular polysaccharide for at least 1 year following BCDT. Anti-dsDNA antibodies derived from the V(H)4.34 immunoglobulin germ line gene (9G4+) were also measured.

RESULTS

All patients achieved peripheral B cell depletion and improved clinically for at least 3 months. Antinucleosome and anti-dsDNA antibodies decreased to a mean +/- SD of 64 +/- 37% and 38 +/- 33% of baseline values, respectively, by 6-8 months post-BCDT. Levels of other autoantibodies and antimicrobial antibodies were generally unchanged. In the 9 of 16 patients who were still well at 1 year, anti-dsDNA antibodies fell to 42 +/- 36% of baseline values at 6-8 months and to 37 +/- 33% at 10-14 months. In patients who had disease flares within 1 year of BCDT, levels of these antibodies decreased to 60 +/- 40% and 83 +/- 93% of baseline values at 6-8 months and at 10-14 months, respectively. Circulating anti-dsDNA antibodies were positive for 9G4 expression in 4 of 6 patients tested, and flares in 2 of these patients were accompanied by rises in 9G4+ anti-dsDNA antibodies.

CONCLUSION

These observations suggest that B cell clones committed to producing antinucleosome and anti-dsDNA antibodies, including the V(H)4.34 subpopulation of anti-dsDNA antibodies, have a relatively rapid turnover compared with B cell clones producing other antibodies. There was also a trend toward a greater and more sustained decrease in anti-dsDNA antibodies in patients with clinical benefit lasting >1 year.

Repeated B cell depletion in treatment of refractory systemic lupus erythematosus

OBJECTIVES

To report the clinical outcome and safety profile of repeated B cell depletion in seven patients with refractory systemic lupus erythematosus (SLE).

METHODS

Since June 2000, seven patients with refractory SLE had repeated cycles of B cell depletion (18 cycles in total, up to three cycles per patient) because of disease relapse. The clinical response (assessed by the British Isles Lupus Activity Guide (BILAG) activity index), duration of B cell depletion, and adverse events in these patients was reviewed.

RESULTS

Four patients (Nos 1, 2, 3, 6) had three cycles of treatment and three (Nos 4, 5, 7) had two cycles. Four of the seven patients (Nos 1, 3, 5, 6) improved. The mean global BILAG scores dropped from 15 to 6 at 5-7 months. The median duration of clinical response and B cell depletion was 13 months and 6 months, respectively. After the third cycle, 2/4 patients (Nos 1 and 2) improved. The median duration of clinical benefit was 12 months. Most patients tolerate re-treatment very well.

CONCLUSION

Re-treatment with B cell depletion of patients with severe SLE is safe and may be effective for 6-12 months on average.

B-cell depletion in the treatment of patients with systemic lupus erythematosus: a longitudinal analysis of 24 patients

OBJECTIVES

To assess the clinical and basic serological consequences of B-cell depletion with rituximab in the treatment of patients with systemic lupus erythematosus (SLE) who have failed conventional immunosuppression.

METHODS

An open study of 24 patients with severe SLE followed for a minimum of 3 months is reported. In the majority of patients (19 out of 24), 6 months follow-up data are described. Disease activity in these patients was assessed every 1-2 months using the British Isles Lupus Assessment Group (BILAG) system and estimates of anti-double-stranded DNA antibodies and serum C3 levels. During the follow-up period, significant side-effects were sought and the reduction in oral prednisolone was recorded. It was our general practice to stop concomitant immunosuppression (e.g. azathioprine, mycophenolate) when B-cell depletion was given (in most cases in the form of two 1 g intravenous infusions of rituximab 2 weeks apart accompanied by two 750 mg intravenous cyclophosphamide infusions and two methylprednisolone infusions of 250 mg each).

RESULTS

Twenty-two patients were female and two male. At the time of B-cell depletion, the mean age was 28.9 yr (range 17-49) and the mean disease duration was 7.9 yr (range 1-18). The global BILAG score (P < 0.00001), serum C3 (P < 0.0005) and double-stranded DNA binding (P < 0.002) all improved from the time of B-cell depletion to 6 months after this treatment. Only one patient failed to achieve B-lymphocyte depletion in the peripheral blood. The period of B-lymphocyte depletion ranged from 3 to 8 months except for one patient who remains depleted at more than 4 yr. Analysis of the regular BILAG assessments showed that improvements occurred in each of the eight organs or systems. The mean daily prednisolone dose fell from 13.8 mg (s.d. 11.3) to 10 mg (s.d. 3.1).

CONCLUSION

In this open study of patients who had failed conventional immunosuppressive therapy, considerable utility in the use of B-cell depletion has been demonstrated. Our data provide strong support for the performance of a full double-blind control trial.

Psychometric properties of the modified dental anxiety scale: an independent replication

AIM

To estimate the internal consistency, test-retest reliability, discriminant and concurrent validity of the Modified Dental Anxiety Scale (MDAS).

METHOD

Survey of a cohort of 135 dental patients in three equal groups (non-anxious; treated anxious; highly anxious). The average age of the total sample was 39.2 years (SD = 13.21), 101 patients (75%) were female. All patients were asked to complete the MDAS, together with the brief form (six items) of the Speilberger Trait Anxiety Inventory (STAI). Thirty-three participants completed the MDAS on a second occasion 2-3 months after the first testing session.

FINDINGS

The MDAS is highly internally consistent (Cronbach alpha = 0.93) and shows good reliability over time (Intra-class correlation coefficient = 0.93). The MDAS was found to discriminate between the three groups of participants defined by self-reported anxiety level, and correlates highly with the Speilberger Trait Anxiety Inventory.

CONCLUSIONS

The MDAS is a highly consistent and reliable measure which has good discriminant and concurrent validity.

Long-acting inhaled anticholinergic therapy improves sleeping oxygen saturation in COPD

Oxygen desaturation occurs during sleep in severe chronic obstructive pulmonary disease (COPD), especially during rapid eye movement (REM) sleep, due to hypoventilation and ventilation-perfusion mismatching, but the possible contribution of airflow limitation is unclear. In a randomised, placebo-controlled, double-blind study of severe, stable COPD patients, the authors compared 4 weeks treatment with a long-acting inhaled anticholinergic agent (tiotropium), taken in the morning (tiotropium-AM), or in the evening (tiotropium-PM), on sleeping arterial oxygen saturation (Sa,O2) and sleep quality. Overnight polysomnography was performed at baseline and after 4 weeks treatment. A total of 95 patients with awake resting arterial oxygen tension < or = 9.98 kPa (75 mmHg) were randomised, with a mean age of 66.4 yrs and mean forced expiratory volume in one second (FEV1) of 32% predicted. A total of 80 patients completed the study, of which 56 fulfilled the polysomnographic criterion of at least 2 h sleep in both sleep study nights and represent the group analysed. Tiotropium significantly improved spirometry compared with placebo. Both tiotropium-AM and tiotropium-PM groups had higher Sa,O2 during REM than placebo (+2.41% and +2.42%, respectively, and both pooled and tiotropium-PM groups had higher Sa,O2 during total sleep time (+2.49% and +3.06%, respectively). End-of-treatment FEV1 correlated with Sa,O2 during REM sleep, however, tiotropium did not change sleep quality. Sustained anticholinergic blockade improves sleeping arterial oxygen saturation without affecting sleep quality.

An admission model for medical schools

Complex societal issues affect medical education and thus require new approaches from medical school admission officers. One of these issues--the recognition that the attributes of good doctors include character qualities such as compassion, altruism, respect, and integrity--has resulted in the recent focus on the greater use of qualitative variables, such as those just stated, for selected candidates. In addition, more emphasis is now being placed on teaching and licensure testing of the attributes of the profession during the four-year curriculum. The second and more contentious issue concerns the system used to admit white and minority applicants. Emphasizing character qualities of physicians in the admission criteria and selection process involves a paradigm shift that could serve to resolve both issues. To make this or any paradigm shift in admission policy, medical schools must think about all the elements of admission and their interrelationships. A model of medical school admission is proposed that can provide understanding of the admission system and serve as a heuristic guide. This model consists of (1) the applicant pool; (2) criteria for selection; (3) the admission committee; (4) selection processes and policies; and (5) outcomes. Each of these dimensions and the interrelationships among the dimensions are described. Finally, a hypothetical example is provided in which the model is used to help a medical school change its admission process to accommodate a new emphasis in the school's mission.

Seizure types, epilepsy syndromes, etiology, and diagnosis

The clinical manifestation of epileptic seizures may vary widely from patient to patient, depending on the region of the brain involved. Over the centuries, many seizure classification systems have been used, and the current most widely used classification system is that of the International League Against Epilepsy (ILAE). The ILAE system divides seizures into those of partial onset and those of generalized onset, depending on whether the initial clinical manifestations indicate that one cortical region or both hemispheres are involved at the onset of the seizure. Partial seizures are then divided into simple partial seizures, in which a fully conscious state is retained, or complex partial seizures, in which consciousness is impaired. A more recent classification system based purely on symptom features and signs has been proposed, and this system may provide advantages for localization, and especially for surgical evaluation. Epilepsy is a condition characterized by recurrent unprovoked seizures. Epilepsy may be idiopathic, cryptogenic, or symptomatic. Idiopathic epilepsies are generally genetic, and while many such syndromes have been described, advances in molecular genetics will undoubtedly reveal many more syndromes in the near future. Cryptogenic epilepsies are those in which an underlying cause is suspected, but the etiology remains undetected. Epilepsies for which there is an underlying structural cause or major metabolic derangement are considered symptomatic. Common causes and diagnostic evaluation are described in this article.

Sustained improvement in rheumatoid arthritis following a protocol designed to deplete B lymphocytes

OBJECTIVES

An open study of B-lymphocyte depletion was undertaken in rheumatoid arthritis (RA) patients to test the hypothesis that B lymphocytes may be essential to disease perpetuation.

METHODS

Five patients with refractory RA were treated with a monoclonal anti-CD20 antibody, cyclophosphamide and prednisolone and followed for 12-17 months. Patient 2 received further treatments at 8 and 12 months and patient 4 at 11 months.

RESULTS

At 26 weeks all patients satisfied the American College of Rheumatology ACR50 and patients 1-3 the ACR70 criteria of improvement, without further therapy. Patients 1, 3 and 5 achieved ACR70 at 1 yr and rheumatoid factor (RF) levels fell to normal. In patients 3 and 5, B lymphocytes returned without relapse. Patient 2 relapsed at 28 weeks and patient 4 at 38 weeks, coincident with the return of B lymphocytes in the presence of raised RF levels. Both achieved ACR70 on retreatment. Adverse events were limited to respiratory episodes (two patients) and marginal thrombocytopenia (one patient).

CONCLUSIONS

These findings are consistent with the concept that RA is critically dependent on B lymphocytes and suggest that B-lymphocyte depletion may be a safe and effective therapy.

Up-regulation and differential expression of the hyaluronan-binding protein TSG-6 in cartilage and synovium in rheumatoid arthritis and osteoarthritis

OBJECTIVE

TSG-6 [the product of tumor necrosis factor (TNF)-stimulated gene-6] is a hyaluronan-binding protein that is present in the synovial fluids of arthritis patients and is secreted by cells of articular joints (e.g. chondrocytes and synoviocytes). This study examines the pattern of TSG-6 expression in normal and diseased cartilage and synovium using immunohistochemical techniques.

DESIGN

A polyclonal antibody was raised against recombinant Link module from human TSG-6 and used to detect the protein in tissue sections taken from osteoarthritis (OA) and rheumatoid arthritis (RA) patients and controls.

RESULTS

There was no TSG-6 detected in normal tissues. In all OA synovium there was intense TSG-6 expression throughout the intimal layer, whereas in RA staining in this region was generally less pronounced and was absent at the synovial surface in tissues exhibiting significant inflammation. In RA TSG-6 was also expressed by infiltrating leukocytes and by cells at the cartilage-synovium pannus junction. TSG-6 immunoreactivity was present in the tunica intima of blood vessels in OA subintima, being particularly noticeable in the thickened smooth muscle of inflamed vessel walls, but was mostly confined to the lumen of the vessel in RA. In cartilage the majority of chondrocytes expressed TSG-6 in both OA and RA, usually with extensive staining in the surrounding matrix.

CONCLUSION

TSG-6 is present within synovium and cartilage of arthritic joints, but not normal controls, and is synthesized by the resident cells. The pattern of TSG-6 expression is consistent with its proposed roles in extracellular matrix (ECM) remodeling and cellular proliferation.

Veterinary school admission interviews, part 1: literature overview

An analysis of the admission interview used by schools in four health professions (veterinary medicine, allopathic medicine, optometry, and dentistry) portrays a largely similar approach to selection interviews: INTERVIEW USE: At least 80% of schools interview applicants. For schools that offer interviews, at least 40% of candidates are interviewed (a strong academic profile is the number one determinant of receiving an interview offer). The interview is one of the three most important selection tools used by schools. Less than 26% of schools fix the interview's weight in the selection process (fixed weights range from 31% to 35%). INTERVIEW PURPOSE AND CONTENT: The most common purposes of the interview are to (1) gather information, (2) make decisions, (3) verify information provided in other parts of the application, (4) recruit candidates, and/or (5) promote public relations. The most common characteristics and skills interviewers are interested in assessing are motivation for the profession, interpersonal skills, and communication skills. The desire to assess cognitive ability with the interview (>25% of schools) is surprising in view of the use of other selection tools (e.g., GPA). INTERVIEW FORMAT: Medical schools are more likely to offer two interviews per candidate, while optometry schools are more likely to offer one interview per candidate. Individual interviews (one interviewer, one candidate) are the predominant format among medical schools, while panel interviews (more than one interviewer, one candidate) are the most common format among optometry schools. The duration of the interview is 30 to 45 minutes. Interview questions most often address facts and knowledge, hypothetical situations, and the ability to meet program requirements. Most interviews do not meet the criteria for a structured interview, which has demonstrated greater validity and reliability than semi-structured or unstructured interviews. INTERVIEWERS: Interviewers are most likely to be health care faculty members (e.g., veterinarians at a veterinary school). Interviewers receive limited training. RECOMMENDATIONS FOR INCREASING INTERVIEW RELIABILITY AND VALIDITY: The purpose(s) of the interview must be clearly articulated so that the interview and interviewer training can be designed to achieve that purpose. Interview structure should be increased by developing a "job analysis" set of questions that is posed to all candidates and scored using behavioral anchors. Interviewers should receive more training in rater bias, listening skills, and interview structure. Panel interviews should be used to increase reliability. Interviewers should not have access to the candidate's application unless the interview is used to verify information. To increase the utility of the interview in the selection process, the weight of the interview in relation to other selection components should be determined.

Study of two cohorts of workers exposed to methyl methacrylate in acrylic sheet production

OBJECTIVES

To study mortality among 4324 workers at two United Kingdom factories, Darwen, Lancashire and Wilton, Cleveland, producing polymethyl methacrylate (PMMA) sheet. The Darwen factory is still active, but the Wilton one was closed in 1970. Also, to investigate patterns of mortality after exposure to methyl methacrylate; in particular, mortality from colon and rectal cancer.

METHODS

All male employees at the Darwen factory with a record of employment in 1949-88 and all men ever employed at the Wilton factory (1949-70) were investigated. The vital status of both cohorts was ascertained on 31 December 1995. The exposure of 1526 subjects at the Darwen plant who were engaged from 1949 onwards could be characterised. The mean duration of exposure was 7.6 years at 13.2 ppm (8 hour time weighted average), although exposures in some work groups were as high as 100 ppm. It was not possible to calculate the cumulative exposure of workers first employed at the Darwen plant before 1949 or workers at the Wilton factory.

RESULTS

In the Darwen cohort, 622 deaths were identified and a further 700 deaths in the Wilton cohort. Mortalities for the cohort were compared with national and local rates and expressed as standardised mortality ratios (SMRs). In the subcohort of Darwen workers with more than minimal exposure to MMA, reduced mortalities compared with national and local rates, were found for all causes (SMR 94), and colorectal cancer (SMR 92), but mortality from all cancers was slightly increased (SMR 104). No relations were found with cumulative exposure to MMA. In the subcohort of Wilton workers, mortality from all causes of death was significantly reduced (SMR 89), but mortality from all cancers (SMR 103) and colorectal cancer (SMR 124) were increased. The excess of colorectal cancer was confined to employees with less than 1 year of employment.

CONCLUSION

The study provided no clear evidence that employment at the factories or exposure to MMA had adversely affected the mortalities of workers.

Seizure outcome after surgery for epilepsy due to malformation of cortical development

PURPOSE

To explore seizure outcome after surgery for focal epilepsy due to malformation of cortical development (MCD), with focus on the role of MRI.

METHODS

Thirty-five patients who had surgery for intractable focal epilepsy due to MCD identified by preoperative MRI and confirmed by histopathologic analysis of resected tissue were studied. Patients were aged 3 months to 47 years (median, 14 years) at the time of surgery. Duration of follow-up was 1 to 7.9 (mean, 3.4) years.

RESULTS

At latest follow-up, 17 patients (49%) had Engel Class I outcome with no seizures or auras only; eight patients (23%) had Class II outcome, with rare disabling seizures; seven patients (20%) had worthwhile improvement; and three patients (9%) had no improvement. Seizure-free outcome tended to be more frequent among patients who had complete resection of unilateral MCD (excluding hemimegalencephaly) based on postoperative MRI (7/12; 58%), compared with patients with unilateral MCD who had incomplete resection (3/11; 27%), but the difference was not significant. The frequency of seizure-free outcome did not differ significantly between children (8/14; 57%), adolescents (7/15; 47%) or adults (2/6; 33%); between patients who had daily (12/24; 50%), weekly (4/9; 44%), or monthly (1/2; 50%) seizures preoperatively; between patients who had temporal (2/6; 33%) or extratemporal or multilobar resections (14/28; 50%); or between patients who were (9/16; 56%) or were not (8/19; 42%) studied with subdural electrodes. Results for all analyses were similar when analyzed at latest available follow-up or at 1 year after surgery.

CONCLUSIONS

Surgery can offer seizure-free outcome for approximately one half of carefully selected patients with intractable focal epilepsy due to MCD. Complete resection of the MRI-apparent lesion may improve the likelihood for favorable outcome. MRI evidence of hemimegalencephaly or bilateral MCD suggests a low likelihood for postoperative freedom from seizures.

Regulation of the bovine kidney microsomal chloride channel p64 by p59fyn, a Src family tyrosine kinase

p64 is a chloride channel of intracellular membranes which is present in regulated secretory vesicles. Mechanisms by which the p64 channel could be regulated are largely unknown. p59(fyn) is a non-receptor tyrosine kinase of the Src family that has been implicated in a variety of intracellular signaling events. The N-terminal portion of p64 has several potential binding sites for Src family SH2 domains. In this paper, we demonstrate that p64 becomes tyrosine phosphorylated when co-expressed with p59(fyn) in HeLa cells. We show that co-expression of p64 with p59(fyn) renders p64 a ligand for the SH2 domain of p59(fyn) and this SH2 binding is eliminated by treating p64 with alkaline phosphatase. Using site-directed mutagenesis, we find that tyrosine 33 in the p64 sequence is necessary for SH2 binding. We also characterized p64-p59(fyn) interactions using native material from bovine kidney. We found that a small fraction of native kidney p64 can bind Fyn SH2 in vitro. Immunoprecipitation of p64 from solubilized kidney membranes yields a kinase activity with the same mobility by SDS-polyacrylamide gel electrophoresis as authentic bovine p59(fyn). Finally, we demonstrate that co-expression of p64 and p59(fyn) in HeLa cells results in enhanced p64-associated chloride channel activity.

CLIC-1 functions as a chloride channel when expressed and purified from bacteria

CLIC-1 is a member of a family of proteins related to the bovine intracellular chloride channel p64 which has been proposed to function as a chloride channel. We expressed CLIC-1 as a glutathione S-transferase fusion protein in bacteria. The fusion protein was purified by glutathione affinity, and CLIC-1 was released from its fusion partner by digestion with thrombin. After further purification, CLIC-1 was reconstituted into phospholipid vesicles by detergent dialysis. Chloride permeability of reconstituted vesicles was assessed using a valinomycin dependent chloride efflux assay, demonstrating increased vesicular chloride permeability with CLIC-1 compared with control. CLIC-1-dependent chloride permeability was inhibited by indanyloxyacetic acid-94 with an apparent IC(50) of 8.6 micrometer. The single channel properties of CLIC-1 were determined using the planar lipid bilayer technique. We found that CLIC-1 forms a voltage-dependent, Cl-selective channel with a rectifying current-voltage relationship and single channel conductances of 161 +/- 7.9 and 67.5 +/- 6.9 picosiemens in symmetric 300 and 150 mm KCl, respectively. The anion selectivity of this activity is Br approximately Cl > I. The open probability of CLIC-1 channels in planar bilayers was decreased by indanyloxyacetic acid-94 with an apparent IC(50) of 86 micrometer at 50 mV. These data convincingly demonstrate that CLIC-1 is capable of forming a novel, chloride-selective channel in the absence of other subunits or proteins.

Beyond affirmative action: one school's experiences with a race-neutral admission process

The authors first review the national debate about affirmative action programs, examine the results of these programs in higher education, and present data from 1995 through 1999 for minority enrollment in U.S., California, and Texas medical schools. Population projections for the state of Texas indicate a national trend that minority groups will outnumber the current majority early in the new millennium. A brief review of studies of the practice patterns of minority physicians concludes that minority physicians serve patients of their own races and/or ethnicities, poor patients, and Medicaid patients in disproportion to their numbers. This rationale, as well as the humanitarian need to develop all persons to their highest potential, led the Texas A&M University Health Science Center College of Medicine to develop a race-neutral process for admission. Changes in the admission process are described and preliminary results are presented. This article is written to stimulate other medical colleges to engage in an ongoing dialog about admission criteria and processes that can effectively select applicants who fit the mission of each medical college and who, as physicians, will care for patients who are members of this country's burgeoning minority groups.

Induction of tumor necrosis factor alpha production by adhered human monocytes: a key role for Fcgamma receptor type IIIa in rheumatoid arthritis

OBJECTIVE

Small IgG rheumatoid factor immune complexes may provide the trigger for macrophage-derived tumor necrosis factor alpha (TNFalpha) production in rheumatoid arthritis. Immune complexes may bind to any of 3 IgG Fc receptors (FcgammaR). Therefore, the ability of monocyte-derived macrophages to produce TNFalpha was examined following ligation of each of the 3 human FcgammaR, using murine monoclonal antibodies (mAb) to each receptor as a model for small immune complexes.

METHODS

Adhered human monocytes expressing all 3 FcgammaR were incubated with murine anti-FcgammaR mAb directed against FcgammaRI, FcgammaRII, or FcgammaRIII. Supernatants were collected at various time points and tested for the presence of TNFalpha and interleukin-1alpha (IL-1alpha) by enzyme-linked immunosorbent assay.

RESULTS

The anti-FcgammaRIII mAb induced adhered human monocytes to release TNFalpha. However, F(ab)2 and Fab fragments of the anti-FcgammaRIII mAb failed to induce TNFalpha production. TNFalpha was undetectable following incubation with the anti-FcgammaRI or anti-FcgammaRII mAb. Furthermore, blocking FcgammaRI or FcgammaRII had no effect on the levels of TNFalpha released in response to the anti-FcgammaRIII mAb. Of the 3 anti-FcgammaR mAb, only anti-FcgammaRIII induced IL-1alpha production from adhered human monocytes, and this was inhibited by the presence of a neutralizing anti-TNFalpha mAb.

CONCLUSION

This study suggests a dominant role for FcgammaRIIIA in the induction of both TNFalpha and IL-1alpha production by human macrophages in rheumatoid arthritis following receptor ligation by small immune complexes. The signaling of TNFalpha production may require the ligation of either 3 FcgammaRIIIA receptors or only 2 FcgammaRIIIA receptors, where one interaction must involve binding via an Fc domain. In addition, IL-1alpha production following FcgammaRIIIA ligation appears to be dependent on the presence of TNFalpha.

Fibroblast biology. Development and differentiation of synovial fibroblasts in arthritis

Synovial fibroblasts occur as two phenotypes--intimal and subintimal. The specialised intimal phenotype includes expression of uridine diphosphoglucose dehydrogenase (UDPGD), vascular cell adhesion molecule-1 (VCAM-1) and complement decay-accelerating factor (DAF). These gene products contribute to specialised functions relating to tissue movement and leucocyte traffic.

Remission of inflammatory arthropathy in association with anti-CD20 therapy for non-Hodgkin's lymphoma

We describe a case involving a 53-yr-old male with a marginal zone B-cell lymphoma, associated with an IgM paraprotein and a rheumatoid factor-negative inflammatory polyarthropathy, treated with monoclonal anti-CD20 antibody. During the subsequent 12 weeks, evidence of synovitis reduced to a negligible level, despite no significant change in lymphoma bulk or paraprotein level. The relationship between the lymphoma and the arthropathy, and the likely mechanism of remission of the arthropathy, are discussed in the context of the potential value of anti-CD20 therapy in rheumatoid arthritis.

Joint immobilization reduces synovial fluid hyaluronan concentration and is accompanied by changes in the synovial intimal cell populations

OBJECTIVES

Synovial fluid (SF) of normal joints contains high hyaluronan (HA) concentrations. However, the mechanism by which these are controlled and how they are influenced by articulation and loading are not established. In this study, we have examined whether immobilization influences SF HA concentration and whether this is associated with alterations in the synovial lining.

METHODS

Hock joints of five adult sheep were immobilized by external fixation. Twelve weeks later, SF and synovium samples were collected. The HA concentration in SF was assayed using an ELISA-based method. Non-specific esterase (NSE) and uridine diphosphoglucose dehydrogenase (UDPGD) activities were assessed in cryostat sections of snap-chilled synovial samples using cytochemical techniques, and UDPGD activity per cell was measured in synovial lining cells by scanning and integrating microdensitometry.

RESULTS

We found that the SF HA concentration was decreased from 1.65+/-0.25 mg/ml in control joints to 0.68+/-0.16 mg/ml in immobilized joints. Synovial intimal cell UDPGD activity decreased from 18.0+/-2.7 U/cell in control joints to 12.2+/-1.5 after immobilization. There was also a decrease in UDPGD-positive intimal cell numbers. Intimal surfaces in controls contained numerous NSE-positive cells, which were rarely observed in intima from immobilized joints.

CONCLUSIONS

These results suggest that immobilization decreases SF HA levels and that this is associated with reduced intimal cell UDPGD activity (essential for HA formation). Immobilization also decreased the prevalence of (NSE-positive) intimal macrophages. These findings suggest that mechanosensitive homeostatic mechanisms exist within the synovial intima.

Double blind glucocorticoid controlled trial of samarium-153 particulate hydroxyapatite radiation synovectomy for chronic knee synovitis

BACKGROUND

Samarium-153 particulate hydroxyapatite (Sm-153 PHYP) is a relatively new radiation synovectomy agent developed for the treatment of chronic synovitis. Although it has been shown that the levels of unwanted extra-articular radiation are lower after intra-articular injection of Sm-153 PHYP than yttrium-90 colloid, its clinical efficacy has not been rigorously studied.

OBJECTIVES

To establish whether Sm-153 PHYP radiation synovectomy results in a clinically useful benefit sustained at one year.

METHODS

In a randomised double blind study, patients received either intra-articular 40 mg triamcinolone hexacetonide alone or 40 mg triamcinolone hexacetonide combined with Sm-153 PHYP in an outpatient clinic.

RESULTS

Sixty patients (28 male, 32 female), median age 51 (18-75) with chronic knee synovitis were studied. Diagnoses included: rheumatoid arthritis (n=29); psoriatic arthritis (n=9); ankylosing spondylitis (n=3); reactive arthritis (n=2); undifferentiated seronegative oligoarthritis (n=13) and miscellaneous inflammatory conditions (n=4). More patients who received Sm-153 PHYP/triamcinolone hexacetonide sustained clinical benefit a year after treatment compared with patients who received corticosteroid alone (12 of 31 (39%) v 6 of 29 (21%), a difference of 18% more patients (95% CI -5% to 41%)) though the difference was not significant (chi(2)=2.31, 0.2>p>0.1, n=60). Despite the variation in injected activity (median 563 MBq, range 218-840 MBq), there was no obvious relation between low levels of injected activity (<555 MBq) and relapse within 12 months of treatment (chi(2) =2.61, 0.2>p>0.1, n=31).

CONCLUSIONS

There was no clear beneficial clinical effect of combined Sm-153 PHYP/triamcinolone hexacetonide injection over triamcinolone hexacetonide alone a year after treatment for chronic knee synovitis.

Do self-perpetuating B lymphocytes drive human autoimmune disease?

Normal immunological memory is thought to be underpinned by T lymphocytes. However, in rheumatoid arthritis there are indications that T-lymphocyte control has been subverted by self-perpetuating B lymphocytes. Potential mechanisms in other autoimmune states are less clear, but a number of observations suggest that misappropriation of immunological memory by B lymphocytes may be a common feature of human autoantibody-associated disease. Put simply, autoantibodies drive their own production. If so, the availability of safe B-lymphocyte-depleting agents provides a potential means for reversal of autoimmunity.

Induced hypothermia as salvage treatment for refractory cardiac failure following paediatric cardiac surgery

OBJECTIVE

Following corrective cardiac surgery in infants and children for congenital heart disease, a persistent low cardiac output refractory to conventional modes of treatment is associated with a mortality approaching 100%. We advocate the use of whole body hypothermia to reduce tissue oxygen demand and provide a degree of cellular protection against ischaemia allowing time for recovery. We describe our experience.

METHODS

Between July 1986 and December 1995, 1885 infants and children underwent surgery (operative mortality, 6%), 1302 requiring cardiopulmonary bypass. Fifty-seven patients had a persistent low cardiac output, impaired respiratory function, decreased urine output and acidosis despite maximal intensive care treatment. Cooling to 32-33 degrees C was therefore started using a thermostatically controlled water filled cooling blanket.

RESULTS

Following cooling, there was a fall in heart rate (P<0.001), a rise in mean arterial pressure (P<0.001) and a fall in mean atrial pressure (P<0.001). Significant (P<0.001) increases in pH and urine output were also recorded. Thirty-one (54%) of the 57 patients treated with cooling survived to leave hospital. No long-term sequelae have been noted in these patients.

CONCLUSION

Induced hypothermia is a useful salvage treatment, in children following corrective cardiac surgery when all conventional treatment has been tried and failed.

Chromosomal analysis of peripheral lymphocytes of patients before and after radiation synovectomy with samarium-153 particulate hydroxyapatite

OBJECTIVE

Radiation synovectomy may be indicated for the treatment of chronic synovitis. A number of factors may affect its current use, including availability, limited evidence for its efficacy compared to intra-articular glucocorticoid, and concerns regarding the potential long-term effects of radiation exposure, particularly in younger patients. Specific chromosome-type abnormalities in peripheral lymphocytes can be useful indicators of whole-body radiation exposure. The frequency of these aberrations has been shown to increase in patients who have had radiation synovectomy using yttrium-90 by up to five times compared to baseline levels. Samarium-153 particulate hydroxyapatite (Sm-153 PHYP) is a new radiopharmaceutical currently on trial which appears to have less extra-articular leakage than yttrium-90 compounds. The aim of this study was to identify any increase in specific chromosome-type abnormalities, using published criteria, in patients following Sm-153 PHYP synovectomy of the knee. The 10 patients (five men, five women) in whom the analyses were performed had a mean age of 47 yr (range 28-70 yr).

RESULTS

There was no increase in scored chromosome-type abnormalities after Sm-153 PHYP synovectomy.

CONCLUSION

This study further supports the relative safety of Sm-153 PHYP compared to other radiopharmaceuticals.

A novel p64-related Cl- channel: subcellular distribution and nephron segment-specific expression

Several closely related proteins that have been implicated as chloride channels of intracellular membranes have recently been described. We report here the molecular cloning and characterization of a new member of this family from human cells. On the basis of sequence similarity, we conclude that this new protein represents the human version of a previously described protein from rat brain named p64H1. The human version of p64H1 (huH1) is a 28.7-kDa protein that shows an apparent molecular mass of 31 kDa by SDS-PAGE. A single 4.5-kb message is detected on Northern blots and is present in all tissues probed. The protein is expressed in an intracellular vesicular pattern in Panc-1 cells that is distinct from the endoplasmic reticulum, fluid-phase endocytic, and transferrin-recycling compartments, but which does colocalize with caveolin. In human kidney, huH1 is highly expressed in a diffuse pattern in the apical domain of proximal tubule cells. huH1 is expressed less abundantly in a vesicular pattern in glomeruli and distal nephron.

Changes in articular synovial lining volume measured by magnetic resonance in a randomized, double-blind, controlled trial of intra-articular samarium-153 particulate hydroxyapatite for chronic knee synovitis

OBJECTIVE

Magnetic resonance techniques have recently been investigated as tools with which to monitor inflammatory joint disease. Our aim was to use a contrast-enhanced T1-weighted protocol to monitor the short-term changes in knee synovial lining volume in a double-blind, randomized, controlled trial of intra-articular samarium-153 particulate hydroxyapatite (Sm-153 PHYP).

METHODS

Twenty-four out-patients with chronic knee synovitis, from a cohort who had been recruited to a long-term clinical efficacy trial, were recruited for this study. Patients received either intra-articular Sm-153 PHYP combined with 40 mg triamcinolone hexacetonide or 40 mg intra-articular triamcinolone hexacetonide alone. Synovial lining volumes were calculated from three-dimensional T1-weighted contrast-enhanced images made before and after contrast enhancement with thresholding and pixel counting, immediately before and 3 months after treatment.

RESULTS

Paired pre- and post-treatment magnetic resonance data were obtained for 18/24 (75%) patients. There was no significant difference in mean pre-treatment synovial volume between the two treatment groups (139 vs 127 ml). A mean reduction in synovial lining volume was detected in the Sm-153 PHYP/steroid-treated group (139 to 110 ml, P = 0.07) and in the steroid-treated group (127 to 58 ml, P < 0.001). The reduction was significantly greater in the steroid-treated group (-61% vs -23%, P < 0.05).

CONCLUSIONS

Short-term changes in articular synovial lining in response to intra-articular treatment for chronic synovitis may be monitored by magnetic resonance imaging. After 3 months, a greater mean reduction in synovial lining volume had occurred in response to intra-articular steroid alone compared to combined Sm-153 PHYP/steroid injection.

The effects of differently weighting interview scores on the admission of underrepresented minority medical students

PURPOSE

Seeking to admit medical students who will later practice medicine in underserved areas, but faced with the national debate over affirmative action programs, the authors evaluate the effects that giving different weightings to academic and interview scores have upon the acceptance or rejection of certain applicants.

METHOD

The authors reviewed the admission records of 439 applicants to Texas A&M University College of Medicine in 1996-97. They compared the applicants actually admitted (accepted under a formula that equally weighted the two scores) with applicants who would have been admitted if the formula had weighted the interview scores at either 60% or 70% and the academic scores at either 40% or 30%.

RESULTS

Weighting the academic score at 40% and the interview score at 60% produced little change in the make-up of the admissions. Weighting the academic score at 30% and the interview score at 70%, however, would have resulted in offers of acceptance to three additional underrepresented minority applicants, two of whom were disadvantaged students.

CONCLUSION

Readjusting the weights of the criteria by which applicants are offered admission to medical schools may help meet the goal of educating doctors who will practice in underserved communities. More research must be done to explore other adjustments to admission criteria.

Technetium-99m human immunoglobulin imaging in patients with subacromial impingement or adhesive capsulitis

Although recognised as useful in detecting soft-tissue inflammation and infection, technetium-99m human immunoglobulin (Tc-99m HIG) has not been widely studied in evaluating regional inflammatory musculoskeletal conditions. Tc-99m HIG scintigraphy was undertaken for consecutive patients referred to a rheumatology clinic with unilateral shoulder pain, diagnosed with either subacromial impingement (n = 12) or adhesive capsulitis (n = 4) from clinical examination, radiographic, and in some cases arthrographic findings. In all patients there were no differences in Tc-99m HIG images between symptomatic and asymptomatic shoulders. The findings are discussed, with reference to patterns of tissue inflammation which have been associated with each of the two conditions and in the context of patients referred to hospital relatively late after onset of symptoms (4-6 months).

Induced hypothermia in the postoperative management of refractory cardiac failure following paediatric cardiac surgery

Postoperative low cardiac output states are a major cause of postoperative mortality in infants and children following corrective cardiac surgery for congenital heart defects. In this unit, whole body hypothermia has been used since 1979 in the management of these low output states when they are refractory to conventional modes of therapy. Twenty cases treated in this way between July 1986 and June 1990 were reviewed in 1992. The current report reviews the 50 further cases treated with moderate hypothermia between July 1990 and December 1995. The median (range) age of patients was 8 months (0 days-16 years) with a median weight of 4.1 kg (2.5-33 kg). Following cooling, there was a decrease in heart rate (p < 0.001), an increase in mean arterial pressure (p < 0.001) and a decrease in mean atrial pressure (p < 0.001). Significant increases in pH and urine output were also noticed, the increase in urine output being greater in the surviving group (p = 0.02). A decrease in platelet count occurred (p < 0.001) but white blood cell count remained unchanged (p = 0.18). Twenty-five of the 50 patients survived to leave hospital. Induced hypothermia does not appear to be associated with any complications and after the failure of all conventional treatment, it seems likely that the technique may have been beneficial to outcome in some patients.

NCC27, a homolog of intracellular Cl- channel p64, is expressed in brush border of renal proximal tubule

NCC27, a 27-kDa homolog of the intracellular chloride channel p64, was recently described as a chloride channel in nuclear membrane. We probed human Northern blots for NCC27 and found an approximately 1.7-kb message in all tissues examined, including kidney, the transcript being most abundant in heart and skeletal muscle.NCC27-specific antisera was raised to a COOH-terminal peptide derived from the NCC27 coding region. Using this antisera, we find NCC27 is expressed in an intracellular vesicular compartment in HeLa cells, PancI cells, and macrophages. In human and mouse kidney, NCC27 is expressed at low levels in most cells of the kidney. NCC27 is highly expressed in glomeruli, in periarterial smooth muscle, and in the apical membrane of a subset of cortical tubule cells. Double staining with nephron segment-specific lectins indicates that the NCC27-expressing cells are proximal tubule cells.

Functional expression of p64, an intracellular chloride channel protein

p64 is a protein identified as a chloride channel by biochemical purification from kidney microsomes. We expressed p64 in HeLa cells using a recombinant vaccinia virus/T7 RNA polymerase driven system. Total cell membranes were prepared from infected/transfected cells and fused to a planar lipid bilayer. A novel chloride channel activity was found in cells expressing p64 and not in control cells. The p64-associated activity shows strong anion over cation selectivity. Single channels show prominent outward rectification with single channel conductance at positive potentials of 42 pS. The chloride channel activity is activated by treatment of the membranes with alkaline phosphatase and inhibited by DNDS and by TS-TM calix(4)arene. Whole membrane anion permeability was determined by a chloride efflux assay, revealing that membranes from cells expressing p64 showed a small but highly significant increase in chloride permeability, consistent with expression of a novel chloride channel activity.

Differential distribution of Fc gamma RIIIa in normal human tissues and co-localization with DAF and fibrillin-1: implications for immunological microenvironments

Fc gamma RIIIa is a cytokine-inducible IgG Fc receptor implicated in the activation of macrophages by immune complexes. Differential expression of Fc gamma RIIIa by macrophages in different tissues may therefore modulate local immune responsiveness. Fc gamma RIIIa expression in normal human tissues was assessed semiquantitatively using microdensitometry. Synovial intimal, serosal, alveolar, salivary gland and placental macrophages, Kupffer cells, and macrophages in mechanically stressed dermis expressed high levels of Fc gamma RIIIa. Less consistent expression was seen in skeletal muscle and lymphoid organs. No significant expression was observed in brain, thyroid, spine, intestine, myocardium, prostate, uterus, flexor forearm dermis, uterus, or kidney. Staining for Fc gamma RIII was also observed on extracellular matrix, and co-localized with both complement decay-accelerating factor and fibrillin-1. It is proposed that differential levels of both cellular and extracellular Fc gamma RIIIa, by modulating the response to immune complexes, may contribute to relative tissue susceptibility to infection and autoimmune disease.