Humanized mouse liver reveals endothelial control of essential hepatic metabolic functions

Hepatocytes, the major metabolic hub of the body, execute functions that are human-specific, altered in human disease, and currently thought to be regulated through endocrine and cell-autonomous mechanisms. Here, we show that key metabolic functions of human hepatocytes are controlled by non-parenchymal cells (NPCs) in their microenvironment. We developed mice bearing human hepatic tissue composed of human hepatocytes and NPCs, including human immune, endothelial, and stellate cells. Humanized livers reproduce human liver architecture, perform vital human-specific metabolic/homeostatic processes, and model human pathologies, including fibrosis and non-alcoholic fatty liver disease (NAFLD). Leveraging species mismatch and lipidomics, we demonstrate that human NPCs control metabolic functions of human hepatocytes in a paracrine manner. Mechanistically, we uncover a species-specific interaction whereby WNT2 secreted by sinusoidal endothelial cells controls cholesterol uptake and bile acid conjugation in hepatocytes through receptor FZD5. These results reveal the essential microenvironmental regulation of hepatic metabolism and its human-specific aspects.

IL-7R licenses a population of epigenetically poised memory CD8+ T cells with superior antitumor efficacy that are critical for melanoma memory

Recurrence of advanced melanoma after therapy is a major risk factor for reduced survival, and treatment options are limited. Antitumor immune memory plays a critical role in preventing melanoma recurrence and memory T cells could be a potent cell-based therapy, but the identity, and functional properties of the required immune cells are incompletely understood. Here, we show that an IL-7Rhi tumor-specific CD8+ population is critical for antitumor memory and can be epigenetically augmented to drive powerful antitumor immune responses. Using a model of functional antimelanoma memory, we found that high IL-7R expression selectively marks a CD8+ population in lymphoid organs that plays critical roles in maintaining tumor remission after immunotherapy or surgical resection. This population has intrinsic cytotoxic activity, lacks markers of exhaustion and has superior antitumor efficacy. IL-7Rhi cells have a functionally poised epigenetic landscape regulated by DNA methylation, which can be augmented by hypomethylating agents to confer improved survival and complete melanoma clearance in naive mice. Importantly, greater than 95% of tumor-specific T cells in draining lymph nodes after therapy express high levels of IL-7R. This overlap between IL-7Rhi and antigen-specific T cells allows for enrichment of a potent functional CD8+ population without determining antigen-specificity, which we demonstrate in a melanoma model without a known antigen. We identify that IL-7R expression in human melanoma is an independent prognostic factor of improved survival. These findings advance our basic understanding of antitumor memory and suggest a cell-based therapy using high IL-7R expression to enrich for a lymph node population with superior antitumor activity that can be augmented by hypomethylating agents.

An update on ductal plate malformations and fibropolycystic diseases of the liver

A variety of cystic and fibrocystic lesions can occur in the liver, which may be single or multiple and etiologically can be acquired or have genetic underpinnings. Although the morphology of ductal plate development and various associated malformations has been well described, the genetic etiologies of many of these disorders are still poorly understood. Multiple clinical phenotypes in the liver are proposed to originate from ductal plate malformations: congenital hepatic fibrosis, Caroli's disease, Von Meyenburg complex, and the liver cysts of autosomal dominant polycystic kidney and liver diseases. Although many of the patients with these disorders, particularly with isolated liver involvement remain asymptomatic, some develop portal hypertension or symptoms from cyst enlargement. Development of hepatocellular malignancy is a risk in a small subset. Recent advances have made it now possible for some of these phenotypes to be genetically defined, and intriguingly animal models of adult polycystic liver disease suggest that abnormal organ development is not required. This review describes the current understanding, genetic underpinning, and key clinicopathologic and imaging features of these fibropolycystic liver diseases.

A novel cell line panel reveals non-genetic mediators of platinum resistance and phenotypic diversity in high grade serous ovarian cancer

OBJECTIVES

Resistance to cancer therapy is an enduring challenge and accurate and reliable preclinical models are lacking. We interrogated this unmet need using high grade serous ovarian cancer (HGSC) as a disease model.

METHODS

We created five in vitro and two in vivo platinum-resistant HGSC models and characterised the entire cell panel via whole genome sequencing, RNASeq and creation of intraperitoneal models.

RESULTS

Mutational signature analysis indicated that platinum-resistant cell lines evolved from a pre-existing ancestral clone but a unifying mutational cause for drug resistance was not identified. However, cisplatin-resistant and carboplatin-resistant cells evolved recurrent changes in gene expression that significantly overlapped with independent samples obtained from multiple patients with relapsed HGSC. Gene Ontology Biological Pathways (GOBP) related to the tumour microenvironment, particularly the extracellular matrix, were repeatedly enriched in cisplatin-resistant cells, carboplatin-resistant cells and also in human resistant/refractory samples. The majority of significantly over-represented GOBP however, evolved uniquely in either cisplatin- or carboplatin-resistant cell lines resulting in diverse intraperitoneal behaviours that reflect different clinical manifestations of relapsed human HGSC.

CONCLUSIONS

Our clinically relevant and usable models reveal a key role for non-genetic factors in the evolution of chemotherapy resistance. Biological pathways relevant to the extracellular matrix were repeatedly expressed by resistant cancer cells in multiple settings. This suggests that recurrent gene expression changes provide a fitness advantage during platinum therapy and also that cancer cell-intrinsic mechanisms influence the tumour microenvironment during the evolution of drug resistance. Candidate genes and pathways identified here could reveal therapeutic opportunities in platinum-resistant HGSC.

Inflammasome activation in infected macrophages drives COVID-19 pathology

Severe COVID-19 is characterized by persistent lung inflammation, inflammatory cytokine production, viral RNA and a sustained interferon (IFN) response, all of which are recapitulated and required for pathology in the SARS-CoV-2-infected MISTRG6-hACE2 humanized mouse model of COVID-19, which has a human immune system1-20. Blocking either viral replication with remdesivir21-23 or the downstream IFN-stimulated cascade with anti-IFNAR2 antibodies in vivo in the chronic stages of disease attenuates the overactive immune inflammatory response, especially inflammatory macrophages. Here we show that SARS-CoV-2 infection and replication in lung-resident human macrophages is a critical driver of disease. In response to infection mediated by CD16 and ACE2 receptors, human macrophages activate inflammasomes, release interleukin 1 (IL-1) and IL-18, and undergo pyroptosis, thereby contributing to the hyperinflammatory state of the lungs. Inflammasome activation and the accompanying inflammatory response are necessary for lung inflammation, as inhibition of the NLRP3 inflammasome pathway reverses chronic lung pathology. Notably, this blockade of inflammasome activation leads to the release of infectious virus by the infected macrophages. Thus, inflammasomes oppose host infection by SARS-CoV-2 through the production of inflammatory cytokines and suicide by pyroptosis to prevent a productive viral cycle.

A humanized mouse model of chronic COVID-19

Coronavirus disease 2019 (COVID-19) is an infectious disease that can present as an uncontrolled, hyperactive immune response, causing severe immunological injury. Existing rodent models do not recapitulate the sustained immunopathology of patients with severe disease. Here we describe a humanized mouse model of COVID-19 that uses adeno-associated virus to deliver human ACE2 to the lungs of humanized MISTRG6 mice. This model recapitulates innate and adaptive human immune responses to severe acute respiratory syndrome coronavirus 2 infection up to 28 days after infection, with key features of chronic COVID-19, including weight loss, persistent viral RNA, lung pathology with fibrosis, a human inflammatory macrophage response, a persistent interferon-stimulated gene signature and T cell lymphopenia. We used this model to study two therapeutics on immunopathology, patient-derived antibodies and steroids and found that the same inflammatory macrophages crucial to containing early infection later drove immunopathology. This model will enable evaluation of COVID-19 disease mechanisms and treatments.

Viral replication in human macrophages enhances an inflammatory cascade and interferon driven chronic COVID-19 in humanized mice

Chronic COVID-19 is characterized by persistent viral RNA and sustained interferon (IFN) response which is recapitulated and required for pathology in SARS-CoV-2 infected MISTRG6-hACE2 humanized mice. As in the human disease, monocytes, and macrophages in SARS-CoV-2 infected MISTRG6-hACE2 are central to disease pathology. Here, we describe SARS-CoV-2 uptake in tissue resident human macrophages that is enhanced by virus specific antibodies. SARS-CoV-2 replicates in these human macrophages as evidenced by detection of double-stranded RNA, subgenomic viral RNA and expression of a virally encoded fluorescent reporter gene; and it is inhibited by Remdesivir, an inhibitor of viral replication. Although early IFN deficiency leads to enhanced disease, blocking either viral replication with Remdesivir or the downstream IFN stimulated cascade by injecting anti-IFNAR2 in vivo in the chronic stages of disease attenuates many aspects of the overactive immune-inflammatory response, especially the inflammatory macrophage response, and most consequentially, the chronic disease itself.

A humanized mouse model of chronic COVID-19 to evaluate disease mechanisms and treatment options

Coronavirus-associated acute respiratory disease, called coronavirus disease 2019 (COVID-19) is an infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). More than 90 million people have been infected with SARS-CoV-2 and more than 2 million people have died of complications due to COVID-19 worldwide. COVID-19, in its severe form, presents with an uncontrolled, hyperactive immune response and severe immunological injury or organ damage that accounts for morbidity and mortality. Even in the absence of complications, COVID-19 can last for several months with lingering effects of an overactive immune system. Dysregulated myeloid and lymphocyte compartments have been implicated in lung immunopathology. Currently, there are limited clinically-tested treatments of COVID-19 with disparities in the apparent efficacy in patients. Accurate model systems are essential to rapidly evaluate promising discoveries but most currently available in mice, ferrets and hamsters do not recapitulate sustained immunopathology described in COVID19 patients. Here, we present a comprehensively humanized mouse COVID-19 model that faithfully recapitulates the innate and adaptive human immune responses during infection with SARS-CoV-2 by adapting recombinant adeno-associated virus (AAV)-driven gene therapy to deliver human ACE2 to the lungs 1 of MISTRG6 mice. Our unique model allows for the first time the study of chronic disease due to infection with SARS-CoV-2 in the context of patient-derived antibodies to characterize in real time the potential culprits of the observed human driving immunopathology; most importantly this model provides a live view into the aberrant macrophage response that is thought to be the effector of disease morbidity and ARDS in patients. Application of therapeutics such as patient-derived antibodies and steroids to our model allowed separation of the two aspects of the immune response, infectious viral clearance and immunopathology. Inflammatory cells seeded early in infection drove immune-patholgy later, but this very same early anti-viral response was also crucial to contain infection.

Prevalence and Correlates of Depressive Symptoms among Medical Students: a Cross-sectional Single-centre Study

BACKGROUND

Depressive symptoms are common among medical students. The aim of the present study was to determine the prevalence and risk factors of depressive symptoms among medical students in Sultan Qaboos University in Oman.

METHOD

A cross-sectional study was conducted among a random sample selected from 1041 medical students at Sultan Qaboos University, Oman. The Patient Health Questionnaire-9 (PHQ-9) was used to screen for depressive symptoms. A logistic regression model was used to determine risk factors for depressive symptoms.

RESULTS

Of 197 medical students selected, 189 (61 men and 128 women) responded. The PHQ-9 results showed that the prevalence of depressive symptoms was 41.3%. In multivariate analysis, female students were more likely than male students to develop depression (adjusted odds ratio = 2.866, p = 0.004). Medical students with a family history of depression were more likely to develop depression than those without a family history of depression (adjusted odds ratio = 4.150, p = 0.014).

CONCLUSIONS

Depressive symptoms are common among medical students in Sultan Qaboos University. Risk factors for depressive symptoms are female sex and family history of depression.

Abstract P1-07-03: Mesenchymal subtype negatively associates with the presence of immune infiltrates within a triple negative breast cancer classifier

Introduction: Lehmann and colleagues (Lehmann et al., 2011) devised a gene expression classification system for triple negative breast cancer (TNBC) consisting of seven subtypes—IM, BL1, BL2, LAR, M, MSL, and UNS (unselected). We (Ring et al., 2016) recently modified this original algorithm of 2188 gene subtyping into a 101-gene algorithm. In addition to a reduction of genes, the 101-gene algorithm has two methodological differences: first, the immunomodulatory (IM) signature was treated not as a subtype but rather as a binary feature of one of the other subtypes (e.g. BL1/IM+, LAR/IM-); second, when tumors—by a predefined correlation coefficient—showed traits of more than one subtype, both subtypes were reported as “dual subtypes.”

Aim: Our aim was to apply the 101-gene algorithm for TNBC subtyping and to establish the relation of TNBC subtypes with their IM-status across several independent data sets.

Methods: 951 patients from four independent TNBC cohorts with available gene expression data were analyzed by the 101-gene algorithm. Of these 848 were classified with at least one subtype.

Results: The distribution of the 5 TNBC subtypes in both single and dual subtypes was 47%,10%,15%,18%,11%, for BL1, BL2, LAR, M, and MSL respectively. The majority of cases gave only one subtype (572, 67%) with M (Mesenchymal) being 9% (n=54) of these. Given this frequency of 9% of M as a baseline, in the remaining 276 (33%) cases with dual subtypes, the expectation that M would be one of the two is 11% (64 subtype calls). However, M is one of the two of the dual subtypes at a much higher frequency of 40% (222 subtype calls, Chi-Squared, P<0.0001). IM+ is a common feature across these cohorts (n=310 or 37%). When examining the IM feature within the patients exhibiting the M subtype as either a single subtype or one of the two dual subtypes (n=276, 33%), IM positive tumors are never of the M phenotype (Chi-Squared, p<0.0001).

Conclusions: We further have confirmed with the 101-gene algorithm that the IM signature inversely associates with the M subtype as it has been observed with the 2188 gene algorithm (Lehmann et al., 2016). Moreover, the M signature is occasionally a confounder of other subtypes however still identifies those tumors negative for immune infiltrates. This raises important opportunities to understand the relationships between intrinsic tumor biology reflected in TNBC subtypes and their interaction with variable immune cell stroma which are the subject of ongoing analyses.

Citation Format: Grigoriadis A, Quist J, Mirza H, Cheang MC, Ring BZ, Hout DR, Bailey DB, Seitz RS, Tutt AN. Mesenchymal subtype negatively associates with the presence of immune infiltrates within a triple negative breast cancer classifier [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P1-07-03.

Abstract P1-05-14: Copy number aberration-induced gene breakage analysis identifies recurrent FOXP1 fusions in breast cancer

Background: Genomic instability is a critical feature of breast cancers, which manifests in genome-wide copy number aberrations (CNA), often causing “gene breakage” and the generation of fusion genes. We aimed to identify aborted transcripts with underlying CNAs and to investigate the molecular landscape of breast cancers harbouring such events.

Methods: A walking student's t-test algorithm was applied to Affymetrix Exon 1.0ST array data of 123 breast cancers to identify regions of aborted transcription and overlaid with DNA breakpoints derived from matched Affymetrix SNP6 ASCAT-segmented copy number. Aborted transcripts were investigated as potential fusion gene partners through RNA-seq analysis of 151 breast cancer samples (TCGA) and 51 breast cancer cell lines (BCCL) using ChimeraScan. Clinical correlates were established for clinicopathological features, genomic instability measures, and gene expression-based molecular classifiers including PAM50, TNBCtype, IntClust subtypes and immune signatures.

Results: One hundred and six genes with recurrent CNA-induced aborted transcription were identified. Aborted transcription showed hormone receptor subtype-specificity for 7 genes (nTNBC=1, nNon-TNBC=6) and was less prevalent in samples of IntClust 2 and IntClust 4 subtypes (p: 0.0043, 0.0011). Aborted transcripts were more frequently observed in samples with greater copy-neutral loss of heterozygosity (p=0.012), while aborted transcription of 54/106 genes significantly affected enrichment of 27 tumor-infiltrating lymphocyte subpopulations.14 aborted transcripts were found as a fusion gene with one partner in RNA-seq of TCGA and BCCL, while 19 were involved in multiple fusion events (range=1-6, median=2). Nine of 106 genes displayed gene breakage and fusion events exclusively in samples with an enriched tandem duplication phenotype. Notably, FOXP1, localised to a tumour suppressor locus at 3p14.1, reported the highest number of fusion configurations (n=6) with concurrent aborted transcription across all RNA-seq datasets (nPRADA=9, nTCGA=38, nBCCL=6).

Conclusion: CNA-induced gene breakage affects the molecular landscape of breast cancers and is linked with many genomic configurations of interest including copy-neutral loss of heterozygosity and tandem duplications. In particular, the role of recurrent gene fusions of the tumour suppressor, FOXP1, in tumourigenesis warrants further investigation.

Citation Format: Mohd Noor A, Maguire S, Watkins J, Quist J, Mirza H, Tutt A, Gillett C, Natrajan R, Grigoriadis A. Copy number aberration-induced gene breakage analysis identifies recurrent FOXP1 fusions in breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P1-05-14.

Mutations Affecting Keratin 10 Surface-Exposed Residues Highlight the Structural Basis of Phenotypic Variation in Epidermolytic Ichthyosis

Epidermolytic ichthyosis (EI) due to KRT10 mutations is a rare, typically autosomal dominant, disorder characterized by generalized erythema and cutaneous blistering at birth followed by hyperkeratosis and less frequent blistering later in life. We identified two KRT10 mutations p.Q434del and p.R441P in subjects presenting with a mild EI phenotype. Both occur within the mutational "hot spot" of the keratin 10 (K10) 2B rod domain, adjacent to severe EI-associated mutations. p.Q434del and p.R441P formed collapsed K10 fibers rather than aggregates characteristic of severe EI KRT10 mutations such as p.R156C. Upon differentiation, keratinocytes from p.Q434del showed significantly lower apoptosis (P-value<0.01) compared with p.R156C as assessed by the TUNEL assay. Conversely, the mitotic index of the p.Q434del epidermis was significantly higher compared with that of p.R156C (P-value<0.01) as estimated by the Ki67 assay. Structural basis of EI phenotype variation was investigated by homology-based modeling of wild-type and mutant K1-K10 dimers. Both mild EI mutations were found to affect the surface-exposed residues of the K10 alpha helix coiled-coil and caused localized disorganization of the K1-K10 heterodimer. In contrast, adjacent severe EI mutations disrupt key intermolecular dimer interactions. Our findings provide structural insights into phenotypic variation in EI due to KRT10 mutations.

Bimodal Influence of Vitamin D in Host Response to Systemic Candida Infection-Vitamin D Dose Matters

Vitamin D level is linked to susceptibility to infections, but its relevance in candidemia is unknown. We aimed to investigate the in vivo sequelae of vitamin D3 supplementation in systemic Candida infection. Implicating the role of vitamin D in Candida infections, we showed that candidemic patients had significantly lower 25-OHD concentrations. Candida-infected mice treated with low-dose 1,25(OH)2D3 had reduced fungal burden and better survival relative to untreated mice. Conversely, higher 1,25(OH)2D3 doses led to poor outcomes. Mechanistically, low-dose 1,25(OH)2D3 induced proinflammatory immune responses. This was mediated through suppression of SOCS3 and induction of vitamin D receptor binding with the vitamin D-response elements in the promoter of the gene encoding interferon γ. These beneficial effects were negated with higher vitamin D3 doses. While the antiinflammatory effects of vitamin D3 are well described, we found that, conversely, lower doses conferred proinflammatory benefits in Candida infection. Our study highlights caution against extreme deviations of vitamin D levels during infections.

Statin pleiotropy prevents rho kinase-mediated intestinal epithelial barrier compromise induced by Blastocystis cysteine proteases

Blastocystis is an enteric parasite that causes acute and chronic intestinal infections, often non-responsive to conventional antibiotics. The effects of Blastocystis infections on human epithelial permeability are not known, and molecular mechanisms of Blastocystis-induced intestinal pathology remain unclear. This study was conducted to determine whether Blastocystis species alters human intestinal epithelial permeability, to assess whether these abnormalities are rho kinase (ROCK)-dependent, and to investigate the therapeutic potential of the HMG-CoA reductase inhibitor Simvastatin in altered intestinal epithelial barrier function. The effect of metronidazole resistant (Mz(r)) Blastocystis isolated from a symptomatic patient on human colonic epithelial monolayers (Caco-2) was assessed. Modulation of enterocyte myosin light chain phosphorylation, transepithelial fluorescein isothiocyanate-dextran fluxes, transepithelial resistance, cytoskeletal F-actin and tight junctional zonula occludens-1 (ZO-1) by parasite cysteine proteases were measured in the presence or absence of HMG-CoA reductase and ROCK inhibition. Blastocystis significantly decreased transepithelial resistance, increased epithelial permeability, phosphorylated myosin light chain and reorganized epithelial actin cytoskeleton and ZO-1. These alterations were abolished by inhibition of enterocyte ROCK, HMG-CoA reductase and parasite cysteine protease. Our findings suggest that cysteine proteases of Mz(r) Blastocystis induce ROCK-dependent disruption of intestinal epithelial barrier function and correlates with reorganization of cytoskeletal F-actin and tight junctional ZO-1. Simvastatin prevented parasite-induced barrier-compromise, suggesting a therapeutic potential of statins in intestinal infections.

Current Views on the Clinical Relevance of Blastocystis spp

Blastocystis is an enteric protistan parasite of uncertain clinical relevance. Recent studies indicate that the parasite is a species complex and humans are potentially hosts to nine Blastocystis subtypes, most of which are zoonotic. Subtype 3 is the most common in prevalence studies, followed by subtype 1. Laboratory diagnosis is challenging; the currently recommended diagnostic approach is trichrome staining of direct smears coupled with stool culture. Polymerase chain reaction testing from stools or culture is useful for determining Blastocystis subtype information. The controversial pathogenesis of Blastocystis is attributed to subtype variations in virulence; although current studies seem to support this idea, evidence suggests other factors also contribute to the clinical outcome of the infection. Clinical signs and symptoms of blastocystosis include abdominal pain, diarrhea, bloating, and flatulence. Extraintestinal manifestations, predominantly cutaneous, also were reported. In vitro and animal studies shed new light on the pathobiology of Blastocystis.

Epidemiology of rheumatoid arthritis in a tertiary care unit, Karachi, Pakistan

OBJECTIVE

To determine the frequency, demographic characteristics, associated co- morbidities and extraarticular manifestations in patients with rheumatoid arthritis (RA) visiting the rheumatology clinic at a tertiary care hospital, Karachi.

METHOD

A retrospective medical chart review of 4900 patients, who visited the rheumatology clinic at Liaquat National Hospital, from January 2005 to June 2007, was conducted. All patients with RA, of both gender and ages 16 years and above, who fulfilled the 1987 ACR criteria were included. Demographic characteristics, base line co-morbidity and extra-articular manifestations were recorded according to pre-defined criteria.

RESULT

Among 4900 patients, 633 (12.9%) visited the rheumatology clinic with RA, female to male ratio being 4:1. The mean age of onset was 38.5 +/- 12.4 years in females and 44.8 +/- 13.12 years in males. Among the age group 16-29 years females were more affected, whereas greater number of males presented between 50-75 years of age. Co-morbidities were found in 35.38% of RA patients. Cardiovascular disease including hypertension (13.79%) and ischaemic heart disease (6.6%) were the most common co-morbidities. RA factor was positive in 85.05% of the patients with hypertension and 88.09% of the patients with ischaemic heart disease. Extra-articular manifestations were reported in 3.47% of patients. Interstitial lung disease (1.57%) was the most common extra-articular manifestation.

CONCLUSION

Significant proportion of patients with female predominance visited the rheumatology clinic at a tertiary care hospital due to RA. Rheumatoid factor may predict the risk of developing cardiovascular disease in patients with RA. The frequency of extra-articular manifestation was lower than that reported in western population.

Blastocystis exhibits inter- and intra-subtype variation in cysteine protease activity

Blastocystis is an enteric protistan parasite of zoonotic potential and poorly understood pathogenesis. We have previously reported that Blastocystis cysteine proteases can degrade human secretory IgA and are also responsible for the induction of IL-8 response in colonic epithelial cells in vitro. Differences in virulence between Blastocystis subtypes have been reported recently in both animal models and clinical studies, although cellular mechanisms for these differences are currently unknown. Parasites such as Giardia intestinalis and Entamoeba histolytica have distinct virulent and non-virulent strains which may be attributable to variations in their cysteine proteases. In the present study, variations in cysteine protease activity was observed between avian (subtype 7) and rodent (subtype 4) isolates of Blastocystis with avian isolates exhibiting approximately two times higher peak cysteine protease activity than rodent isolates. Cysteine protease activity and parasite cell size varied over time within cultures of the same isolate. An association between parasite cell size and protease activity was observed.

Conscious sedation with intermittent midazolam and fentanyl in electrophysiology procedures

OBJECTIVES

To determine the safety and efficacy of intermittent midazolam and fentanyl conscious sedation for electrophysiology procedures (EP).

BACKGROUND

Intermittent midazolam and fentanyl conscious sedation was administered in 700 consecutive cases (175 radiofrequency ablations, 163 EP studies, 261 pacemakers, and 101 implantable cardioverter-defibrillators) for 471 patients (239 males, 51%) mean age 65 +/- 15 years. The mean dose of midazolam was 0.063 mg/kg/hr and fentanyl was 0.591 microgram/kg/hr.

METHODS

Cardiac rate and rhythm were monitored continuously, while blood pressure and arterial oxygen saturation were noninvasively assessed every 5 minutes. Drugs were administered in aliquots of 0.5 to 2.0 mg of midazolam and 6.25 to 25 micrograms of fentanyl as determined by clinical condition every 15 to 30 minutes.

RESULTS

There were no deaths. In no case was endotracheal intubation required. Mild hypoxemia (SaO2 > 80%, but < 90%) occurred in 17 cases (2.4%) and was easily reversed with verbal stimulation and oropharyngeal repositioning (12 cases, 1.7%), increased F1O2 (3 cases, 0.4%), or intravenous naloxone (2 cases, 0.3%). Reversible hypotension (systolic blood pressure < 90, but > 60 mmHg) occurred in 14 patients (2.0%) and was corrected with intravenous crystalloid bolus or flumazenil (10 cases, 1.4%) or inotrope infusion (4 cases, 0.6%). No patient stay was prolonged due to sedation. Only five patients (0.7%) had any recollection of the procedure, while two (0.3%) were aware of pain. All hypoxemic episodes occurred during the first hour, whereas 43% (6/14) of hypotensive episodes occurred after the first hour.

CONCLUSION

Conscious sedation with intermittent midazolam and fentanyl is safe and efficacious for a broad range of EP procedures.

Complex regional pain syndrome (CRPS) with resistance to local anesthetic block: a case report

We present a case of complex regional pain syndrome (CRPS) Type 1 in a 12-year-old girl. The patient did not respond to the usual therapeutic modalities used to treat CRPS, including physical therapy, lumbar sympathetic block, epidural local anesthetic block, intravenous lidocaine infusion, or other oral medications. Of note is the fact that, during epidural block, the patient demonstrated a resistance to local anesthetic neural blockade in the area of the body involved with the pain problem. The mechanism of this resistance could be related to the changes in the dorsal horn cells of the spinal cord, secondary to activation of N-methyl-D-aspartate receptors, which may play a role in the pathophysiology of this pain syndrome.

The standardization of the Denver Developmental Screening Test on Arab children from the Middle East and north Africa

A total of 936 children of Arab ethnic origin and culture were tested for the purpose of the standardization of the Denver Developmental Screening Test (DDST) on children from the Middle East and North Africa. There were 457 males and 479 females included in the study, with a race distribution of 216 white, 96 black, and 624 of mixed racial origin. The sample was divided into three age groups, with the age-range all-inclusive being from birth to six years. Five social classes were included. Accordingly, a new DDST screening form was designed and presented for the population studied. Age norms of developmental milestones on the personal-social, fine motor-adaptive, language, and gross motor skills are presented here.

Vascular endothelial growth factor induces tissue factor and matrix metalloproteinase production in endothelial cells: conversion of prothrombin to thrombin results in progelatinase A activation and cell proliferation

Production of vascular endothelial growth factor (VEGF) by cancer cells at invasive and metastatic sites is an important aspect of tumor angiogenesis. Although known primarily as a mitogen and a vascular permeability factor (VPF) for endothelial cells, VEGF/VPF has been proposed to induce the expression of procoagulant factors in endothelial cells. In this study, we have explored the ramifications of VEGF induction of tissue factor (TF) in human umbilical vein endothelial cells (HUVECs) and subsequent activation of progelatinase A. Within 3 hr of incubation with VEGF/VPF, endothelial cells accelerate TF generation as measured using chromogenic substrate assays for coagulation factors Xa and thrombin. Incubation of VEGF/VPF-pre-treated cells with prothrombin and factors X, Va, and VIIa at 37 degrees C and subsequent generation of thrombin resulted in activation of secreted endothelial progelatinase A as demonstrated by gelatin zymography. Anti-thrombin III or antibodies to TF inhibited thrombin generation and progelatinase A activation. VEGF/VPF also directly increased HUVEC secretion of interstitial collagenase, tissue inhibitor of metalloproteinases (TIMP-1) and, to a lesser extent, gelatinase A. The effect of thrombin on endothelial proliferation in serum-free media was examined. Thrombin was a growth factor for HUVECs at a lower dose than that required for progelatinase A activation. Whereas TIMP-2 abrogated thrombin-induced progelatinase A activation, it had no significant effect on thrombin-induced endothelial cell growth. We propose that an early step in tumor angiogenesis involves VEGF-induced thrombin generation and increased MMP production with subsequent activation of endothelial progelatinase A and degradation of the underlying basement membrane.

Mitogenic responses mediated through the proteinase-activated receptor-2 are induced by expressed forms of mast cell alpha- or beta-tryptases

The proteinase-activated receptor-2 (PAR-2) is the second member of a putative larger class of proteolytically activated receptors that mediate cell activation events by receptor cleavage or synthetic peptidomimetics corresponding to the newly generated N-terminus. To further study the previously identified mitogenic effects of PAR-2, we used the interleukin-3 (IL-3)-dependent murine lymphoid cell line, BaF3, for generation of stable cell lines expressing PAR-2 (BaF3/PAR-2) or the noncleavable PAR-2 mutant PAR-2(Arg36 --> Ala36). Only BaF3 cells expressing either wild-type or mutated receptor exhibited mitogenic responses when grown in IL-3-deficient media supplemented with PAR-2 activating peptide (SLIGRL, PAR39-44). This effect was dose dependent with an EC50 of approximately 80 micromol/L, sustained at 24, 48, and 72 hours, and was also demonstrable using thrombin receptor peptide TR42-47. Because tryptase shares approximately 70% homology with trypsin (previously shown to activate PAR-2), we studied recombinantly expressed forms of alpha- and beta-tryptases as candidate protease agonists for PAR-2. Hydrolytic activity of the chromogenic substrate tosyl-glycyl-prolyl-argly-4-nitroanilide acetate was present as a sharp peak at Mr approximately 130, confirming the presence of secretable and functionally active homotetrameric alpha- and beta-tryptases in transfected COS-1 cells. Dose-dependent proliferative responses were evident using either secreted form of tryptase with maximal responses seen at approximately 3 pmol/L (0.1 U/L). Receptor proteolysis was necessary and sufficient for mitogenesis because active site-blocked tryptase failed to induce this response, and proliferative responses were abrogated in BaF3 cells expressing PAR-2(Arg36 --> Ala36). These results specifically identify both forms of mast cell tryptases as serine protease agonists for PAR-2 and have implications for elucidating molecular mechanisms regulating cellular activation events mediated by proteases generated during inflammatory, fibrinolytic, or hemostatic-regulated pathways.

The proteinase activated receptor-2 (PAR-2) mediates mitogenic responses in human vascular endothelial cells

Proteolytically cleaved receptors, typified by the functional thrombin receptor (TR), represent a novel class of receptors that mediate signaling events by functional coupling to G proteins. Northern blot analysis completed with a human proteinase activated receptor-2 (PAR-2) cDNA as probe demonstrated the approximately 3.5kb PAR-2 transcript in total cellular RNA from human umbilical vein endothelial cells (HUVEC). Microspectrofluorimetry using Fura2-loaded HUVEC demonstrated a dose-dependent elevation in intracellular calcium transients ([Ca2+]i) to murine PAR39-44 (SLIGRL, putative neoligand after cleavage), with an approximate EC50 of 30 microM, and evidence for homologous desensitization with complete recovery at 45 min. Xenopus oocytes microinjected with TR cRNA failed to respond to 200 microM PAR39-44, and TR-targeted antisense oligonucleotides specifically abrogated thrombin-induced but not PAR39-44-mediated [Ca2+]i, excluding the possibility that TR/PAR-2 cell-surface coexpression was structurally linked. HUVEC incubated with PAR39-44 demonstrated a dose- and time-dependent mitogenic response similar to that seen with thrombin or TR42-47 (TR-activating peptide, SFLLRN). Preactivation of HUVEC with either PAR39-44 or thrombin resulted in heterologous desensitization to the corresponding agonist, an effect that was mediated primarily by TR internalization as evaluated by immunofluorescence and quantitative ELISA. These results ascribe a previously unrecognized function to the PAR-2 receptor, imply that a natural enzyme agonist may circulate in plasma, and suggest the presence of an additional regulatory mechanism controlling receptor activation events in vascular endothelial cells.

A survey of new long-stay hospital patients in an Irish health board area

OBJECTIVES

The aims of this study were to determine the number and rate of accumulation of new long-stay hospital patients in one of Ireland's eight health board areas, to describe their demographic and clinical features, and to assess their needs in relation to possible community placement.

METHODS

Demographic and clinical information was obtained on all patients over age 17 who had been continuously hospitalized in area hospitals for more than one year and less than six years on the census day of March 1, 1992. The Community Placement Questionnaire was used to rate the patients' social functioning, problem behavior, physical disability, social contact, and needs for accommodation and day care.

RESULTS

The survey identified 175 new long-stay patients, mainly middle aged to elderly. Schizophrenia was the most common psychiatric diagnosis. The bed occupancy rate for these patients was 14 per 100,000 population, and the annual accumulation rate was 2.3 per 100,000 population.

CONCLUSIONS

New long-stay patients were chronically ill with significant psychiatric and social disabilities. Involuntary patients were overrepresented in the group. Two-thirds could be placed in the community if facilities were available and had sufficiently high staffing levels.

The VLA-2 (alpha 2 beta 1) I domain functions as a ligand-specific recognition sequence for endothelial cell attachment and spreading: molecular and functional characterization

The integrin VLA-2 (alpha 2 beta 1), generally considered to represent the specific collagen receptor on human endothelial cells, contains an alpha 2-subunit inserted I domain with structural similarity to the type A domains found within the recently described superfamily of receptor-ligand recognition proteins. This region of the cDNA has now been isolated and used for molecular and functional characterization of this heterodimeric receptor complex. Comparative sequence analysis with the porcine homologue revealed 93% amino acid sequence identity, suggestive of a developmentally conserved function. To complete structure/function studies, this region of the human cDNA was expressed as a chimeric protein in Escherichia coli, and a rabbit polyclonal antibody (anti-I domain) was used to study determinants of endothelial cell attachment and spreading in vitro. Quantifiable and visual disruption of endothelial cell attachment to gelatin, type I collagen, and laminin was evident using the specific anti-I domain antibody, with minimal inhibitory effects demonstrable using fibronectin or fibrinogen matrices. Therefore, these data would suggest that the alpha 2 beta 1 I domain confers ligand-binding specificity for both known alpha 2 beta 1 substrates (laminin and collagen), and that this region subserves a regulatory function in the molecular processes controlling endothelial cell attachment and spreading in vitro.