PNPLA3, obesity and heavy alcohol use in cirrhosis patients may exert a synergistic increase hepatocellular carcinoma risk

BACKGROUND & AIMS

In patients with cirrhosis, continued heavy alcohol consumption and obesity may increase risk of hepatocellular carcinoma (HCC). We examined whether germline susceptibility to hepatic steatosis not only independently predisposes to HCC but may also act synergistically with other risk factors.

METHODS

We analyzed data from 1911 patients in two multicenter prospective cohort studies in the U.S. We classified patients according to alcohol consumption (current heavy vs. not current heavy), obesity (body mass index [BMI] ≥30 vs. <30), and PNPLA3 I148M variant status (carrier of at least one G risk allele vs. noncarrier). We examined the independent and joint effects of these risk factors on risk of developing HCC using Cox regression with competing risks.

RESULTS

Mean age was 59.6y, 64.3% male, 28.7% Hispanic, 18.3% non-Hispanic Black, 50.9% were obese, 6.2% had current heavy alcohol consumption, and 58.4% harbored at least one PNPLA3 G-allele. 116 patients developed HCC. Compared to PNPLA3 noncarriers without heavy alcohol consumption, HCC risk was 2.65-fold higher (hazard ratio [HR], 2.65; 95% confidence interval [CI], 1.20-5.86) for carriers who had current heavy alcohol consumption. Compared to noncarrier patients without obesity, HCC risk was higher (HR, 2.40; 95%CI, 1.33-4.31) for carrier patients who were obese. PNPLA3 and alcohol consumption effect was stronger among patients with viral etiology of cirrhosis (HR, 3.42; 95% CI, 1.31-8.90). PNPLA3 improved 1-year risk prediction for HCC when added to a clinical risk model.

CONCLUSIONS

The PNPLA3 variant may help refine risk stratification for HCC in patients with cirrhosis with heavy alcohol consumption or obesity who may need specific preventive measures.

Serum biomarker signature is predictive of the risk of hepatocellular cancer in patients with cirrhosis

BACKGROUND

Inflammatory and metabolic biomarkers have been associated with hepatocellular cancer (HCC) risk in phases I and II biomarker studies. We developed and internally validated a robust metabolic biomarker panel predictive of HCC in a longitudinal phase III study.

METHODS

We used data and banked serum from a prospective cohort of 2266 adult patients with cirrhosis who were followed until the development of HCC (n=126). We custom designed a FirePlex immunoassay to measure baseline serum levels of 39 biomarkers and established a set of biomarkers with the highest discriminatory ability for HCC. We performed bootstrapping to evaluate the predictive performance using C-index and time-dependent area under the receiver operating characteristic curve (AUROC). We quantified the incremental predictive value of the biomarker panel when added to previously validated clinical models.

RESULTS

We identified a nine-biomarker panel (P9) with a C-index of 0.67 (95% CI 0.66 to 0.67), including insulin growth factor-1, interleukin-10, transforming growth factor β1, adipsin, fetuin-A, interleukin-1 β, macrophage stimulating protein α chain, serum amyloid A and TNF-α. Adding P9 to our clinical model with 10 factors including AFP improved AUROC at 1 and 2 years by 4.8% and 2.7%, respectively. Adding P9 to aMAP score improved AUROC at 1 and 2 years by 14.2% and 7.6%, respectively. Adding AFP L-3 or DCP did not change the predictive ability of the P9 model.

CONCLUSIONS

We identified a panel of nine serum biomarkers that is independently associated with developing HCC in cirrhosis and that improved the predictive ability of risk stratification models containing clinical factors.

Bioimpedance analysis predicts the etiology of cirrhosis in a prospective cohort study

BACKGROUND

Obesity is associated with an increased risk of developing cirrhosis. However, body mass index (BMI) and waist-to-hip ratio (WHR) may not be indicative of body composition parameters that predispose to cirrhosis. Bioimpedance analysis (BIA) is a noninvasive cost-efficient method for more detailed estimation of body composition.

METHODS

We examined patients with cirrhosis who underwent BIA as part of enrollment into a prospective cohort study. We examined the correlation between BIA variables, BMI, and WHR. We performed sex-adjusted and race-adjusted and race-specific multivariable logistic regression analyses to examine the association between anthropometric variables and risk factors [NAFLD, alcohol-associated liver disease (ALD), and HCV].

RESULTS

We analyzed data from 348 cirrhosis patients; 23.3% were women; 48.3% were non-Hispanic White; 19.3% were Hispanic; and 30.7% were African American. The cirrhosis etiology was 21.8% NAFLD, 56.9% HCV mostly cured, and 11.5% ALD. Several BIA variables correlated well with BMI, and others showed modest correlations, but none correlated well with WHR. Higher body fat mass and basal metabolic rate were positively associated, while higher lean body mass, dry lean mass, total body water, or skeletal muscle mass were negatively associated with NAFLD. Associations between these BIA parameters and ALD-related cirrhosis were in the opposite direction. These associations of BIA variables were seen only in Hispanic and non-Hispanic White patients but not non-Hispanic Blacks. BIA variables were more predictive of cirrhosis etiology than BMI or WHR.

CONCLUSIONS

Among patients with cirrhosis, several BIA-derived measurements indicative of body fat and muscle are associated with NAFLD and ALD etiology. BIA variables show stronger associations, as well as race/ethnicity-specific associations, with cirrhosis etiology than those of BMI or WHR.

Anti-human immunodeficiency virus-1 activity of MoMo30 protein isolated from the traditional African medicinal plant Momordica balsamina

BACKGROUND

Plants are used in traditional healing practices of many cultures worldwide. Momordica balsamina is a plant commonly used by traditional African healers as a part of a treatment for HIV/AIDS. It is typically given as a tea to patients with HIV/AIDS. Water-soluble extracts of this plant were found to contain anti-HIV activity.

METHODS

We employed cell-based infectivity assays, surface plasmon resonance, and a molecular-cell model of the gp120-CD4 interaction to study the mechanism of action of the MoMo30-plant protein. Using Edman degradation results of the 15 N-terminal amino acids, we determined the gene sequence of the MoMo30-plant protein from an RNAseq library from total RNA extracted from Momordica balsamina.

RESULTS

Here, we identify the active ingredient of water extracts of the leaves of Momordica balsamina as a 30 kDa protein we call MoMo30-plant. We have identified the gene for MoMo30 and found it is homologous to a group of plant lectins known as Hevamine A-like proteins. MoMo30-plant is distinct from other proteins previously reported agents from the Momordica species, such as ribosome-inactivating proteins such as MAP30 and Balsamin. MoMo30-plant binds to gp120 through its glycan groups and functions as a lectin or carbohydrate-binding agent (CBA). It inhibits HIV-1 at nanomolar levels and has minimal cellular toxicity at inhibitory levels.

CONCLUSIONS

CBAs like MoMo30 can bind to glycans on the surface of the enveloped glycoprotein of HIV (gp120) and block entry. Exposure to CBAs has two effects on the virus. First, it blocks infection of susceptible cells. Secondly, MoMo30 drives the selection of viruses with altered glycosylation patterns, potentially altering their immunogenicity. Such an agent could represent a change in the treatment strategy for HIV/AIDS that allows a rapid reduction in viral loads while selecting for an underglycosylated virus, potentially facilitating the host immune response.

Identification of a Novel Anti-HIV-1 Protein from Momordica balsamina Leaf Extract

Our lab investigates the anti-HIV-1 activity in Momordica balsamina (M. balsamina) leaf extract. Traditional Senegalese healers have used M. balsamina leaf extract as a part of a plant-based treatment for HIV/AIDS infections. Our overall goal is to define and validate the scientific basis for using M. balsamina leaf extract as a part of the traditional Senegalese treatment. As an initial characterization of this extract, we used activity-guided fractionation to determine the active ingredient's solubility and relative size. We found that M. balsamina leaf extract inhibits HIV-1 infection by >50% at concentrations of 0.02 mg/mL and above and is not toxic over its inhibitory range (0-0.5 mg/mL). We observed significantly more antiviral activity in direct water and acetonitrile extractions (p ≤ 0.05). We also observed significantly more antiviral activity in the aqueous phases of ethyl acetate, chloroform, and diethyl ether extractions (p ≤ 0.05). Though most of the antiviral activity partitioned into the aqueous layers, some antiviral activity was present in the organic layers. We show that the active agent in the plant extracts is at least 30 kD in size. Significantly more antiviral activity was retained in 3, 10, and 30 kD molecular weight cutoff filters (p ≤ 0.05). In contrast, most of the antiviral activity passed through the 100 kD filter (p ≤ 0.05). Because the active anti-HIV-1 agent presented as a large, amphiphilic molecule we ran the purified extract on an SDS-page gel. We show that the anti-HIV-1 activity in the leaf extracts is attributed to a 30 kDa protein we call MoMo30. This article describes how MoMo30 was determined to be responsible for its anti-HIV-1 activity.

Facilitators and barriers to a family empowerment strategy to improve healthcare worker hand hygiene in a resource-limited setting

OBJECTIVES

The World Health Organization recommends empowering patients/families to remind healthcare workers (HCWs) to perform hand hygiene (HH). We sought to understand acceptability of a family empowerment strategy in a Vietnamese pediatric intensive care unit (PICU).

METHODS

With end-user input, we designed a tool to help families in a PICU in Vietnam to remind HCWs to perform HH. We conducted 3 preliminary focus group discussions (FGDs) with patients' family members (n = 8), physicians (n = 9), and nurses (n = 8) to understand acceptability of preliminary tools, attitudes towards HH and barriers to HH. Tools were then modified and implemented in a 5-week intervention study. We then conducted 3 more FGDs with families (n = 7), physicians (n = 7), and nurses (n = 8). Discussions were analyzed using qualitative directed content analysis. Families who used the tool were asked to complete written surveys.

FINDINGS

Both family members and HCWs felt that HCWs had a responsibility to perform HH. Barriers to performing HH were identified, including forgetfulness and time constraints. Family members felt shy reminding HCWs to perform HH. However, the HH reminder tool was acceptable, and some felt it could overcome barriers to reminding HCWs to perform HH. HCWs felt embarrassed when reminded to perform HH, but felt that the reminder was useful. Nearly all (99%) survey respondents felt that family members should speak up if they noticed HCWs omitting HH.

CONCLUSIONS

A tool given to families to remind HCWs to perform HH was largely acceptable in a pediatric ICU in Vietnam. Perceived benefits of improving HH were felt to surmount barriers to tool use.

1192. A Visual Family Empowerment Tool Is Associated with Increased Healthcare Worker Hand Hygiene in a Pediatric Intensive Care Unit in Vietnam

Background

Hand hygiene (HH) is the most effective way to prevent healthcare-associated infections. The World Health Organization (WHO) recommends empowering patients and families to remind healthcare workers (HCWs) to perform HH. The effectiveness of patient and family empowerment tools in Southeast Asia is unknown.

Methods

We performed a prospective intervention study in an intensive care unit of a pediatric referral hospital in Vietnam. Using family and HCW input, we created a visual tool for families to use to remind HCWs to perform HH. For 2 weeks pre-intervention, we collected baseline data on HH performance, method (hand rub or soap and water), adequacy, HCW type (e.g., physician, nurse), and WHO 5 moments of HH using direct, unobtrusive observation. During a subsequent 3-week intervention period, consenting families were provided the visual tool and educated on its use to prompt HCW HH. Prospective collection of outcome data continued during the intervention period. The primary outcome was change in HCW HH between baseline and intervention periods. Multivariable logistic regression models were used to identify independent predictors of HH.

Results

A total of 2,014 pre-intervention and 2,498 intervention period HH opportunities were observed. During the intervention period, 73 families received visual reminder tools and education. Overall HCW HH was 46% pre-intervention, which increased to 73% in the intervention period (P < 0.001). Lowest HH adherence in both periods occurred after HCW contact with patient surroundings (WHO Moment 5; 16% pre-intervention and 24% intervention). In multivariable analyses, the odds of HCW HH during the intervention period were significantly higher than pre-intervention (OR 2.94 [95% CI 2.54 – 3.41], P < 0.001) after adjusting for observation room, HCW type, time of observation (weekday business hours vs. evening/weekend), and HH moment. Among completed HH opportunities, HH adequacy was >90% in both periods.

Conclusion

Introduction of a visual empowerment tool was associated with significant improvement in HH adherence among HCWs in a Vietnamese pediatric intensive care unit. More research is needed to explore acceptability and barriers to the use of such tools in other low- and middle-income settings.

Disclosures

All authors: No reported disclosures.

Factors associated with concurrent heroin use among patients on methadone maintenance treatment in Vietnam: A 24-month retrospective analysis of a nationally representative sample

BACKGROUND

Methadone maintenance treatment (MMT) is highly effective for reducing heroin use and HIV transmission among people who inject opioids. We sought to measure and understand factors associated with continued heroin use, a critical factor affecting treatment outcome among MMT patients in Vietnam.

METHOD

We collected data from medical charts of a nationally representative sample of patients who were on MMT from May 2008 to December 2013. We selected 10 MMT clinics using probability proportional to size and 50 patients/clinic by systematic random sampling. Concurrent heroin use was defined by self-report/positive urine test recorded in patient charts during month 3, 6, 12, and 24 after MMT initiation. We used multivariable logistic regression to identify factors associated with concurrent heroin use over the first 24 months in treatment.

FINDINGS

All clients used heroin at baseline; concurrent heroin use was 55% at month 3; 19%, 14.6% and 15.2% at month 6, 12, and 24, respectively. Having no family emotional/financial support at baseline versus having this support (AOR = 2.03; 95% confidence interval [CI] = 1.17-3.53); using heroin for <15 years versus ≥15 years at baseline (AOR = 1.55; 95% CI = 1.01-2.38); being HIV-infected/not on antiretroviral treatment (ART; AOR = 1.79; 95% CI = 1.07-2.98) or being HIV infected/on ART (AOR = 2.39; 95% CI = 1.61-3.55), versus not being HIV infected; baseline methamphetamine use versus non-use (AOR = 2.68; 95% CI = 1.08-6.65), were associated with increased odds of concurrent heroin use among patients.

CONCLUSION

The association between concurrent heroin use among MMT patients and lack of family emotional/financial support, highlights the critical importance of these types of support for successful treatment. Association with shorter heroin use history suggests motivational enhancement may reduce concurrent heroin use. Living with HIV, whether on ART or not, is associated with increased concurrent heroin use and suggests safe injection commodities and education, and drug-drug interaction management, are needed for this subgroup. Though few MMT clients reported baseline methamphetamine use, its association with later heroin use suggests the need for effective methamphetamine use interventions.

High hepatitis C virus (HCV) prevalence among men who have sex with men (MSM) in Vietnam and associated risk factors: 2010 Vietnam Integrated Behavioural and Biologic Cross-Sectional Survey

BACKGROUND

Hepatitis C virus (HCV) is an increasing health issue among key populations such as men who have sex with men (MSM). We sought to assess the burden of and risk factors for HCV among MSM in Vietnam.

METHODS

We analysed behavioural and demographic data and stored specimens from MSM surveyed in four provinces through Vietnam's 2009-2010 Integrated Biologic and Behavioural Survey, which used probability-based, respondent-driven sampling. Commercial hepatitis B surface antigen (HBsAg) and HCV/antibody (HCV Ag/Ab) testing were performed on archived sera with follow-up PCR for HCV RNA and genotype determination.

RESULTS

Among the 1588 MSM surveyed, the median (range) frequency, by province, of HCV Ag/Ab detection was 28.4% (13.7%-38.8%); 84.5% (83.1%-100%) among HIV-infected and 21.9% (8.9%-28.2%) among HIV-uninfected. HCV prevalence was higher in northern Hanoi and Hai Phong provinces than in southern Ho Chi Minh City and Chan Tho provinces. Among a convenience sample of 67 HCV Ag/Ab+ MSM, 67.2% were HCV RNA+; of 41 genotyped, 73.2% were genotype 1. HBsAg prevalence varied from 8.5% to 27.4%. In the multivariable logistic regression analysis, being HIV-infected (adjusted OR (aOR) 19.0; 7.0-51.9), ever having used injected drugs (aOR 4.4; 1.6-12.4) and age >25 years were significant risk factors for testing HCV Ag/Ab+.

CONCLUSIONS

HCV infection in Vietnam appears to be high among MSM, particularly among HIV-infected MSM, with a north-south gradient. Given overlapping risk behaviours and associations between HCV and HIV, integrating HIV and HCV programme services to prevent both HIV and HCV transmission among MSM is indicated.

The association between maternal parity and birth defects

BACKGROUND

Previous studies observed that first birth is associated with an increased risk of some categories of birth defects. However, multiple statistical tests were conducted and it was unclear which of these associations would be replicated in a larger study. We used a large database to assess the association between maternal parity and 65 birth defects including birth defects that have not been previously studied.

METHODS

Using data from the Texas Birth Defects Registry for years 1999-2009, the risk of a birth defect occurring in a first, third, or fourth or higher birth was compared to the risk of a birth defect occurring in a second birth.

RESULTS

Women having their first birth had significantly increased odds of having an infant with 24 of 65 categories of birth defects when compared to women having their second birth. We also observed associations between first birth and an increased risk of five birth defects not previously reported (small penis, preaxial polydactyly, anomalies of the thoracic vertebrae, anomalies of the lumbar vertebrae, and sacroccygeal anomalies). Women having their third or fourth or higher birth had significantly increased odds of giving birth to infants with five of 65 birth defects when compared to second births.

CONCLUSIONS

Our observations regarding the categories of birth defects that were associated with first births were highly consistent with observations from two previous studies. Research into biological, behavioral, and environmental factors that may increase the risk of specific birth defects among first births is needed to further explore these associations.

Findings from integrated behavioral and biologic survey among males who inject drugs (MWID) - Vietnam, 2009-2010: evidence of the need for an integrated response to HIV, hepatitis B virus, and hepatitis C virus

INTRODUCTION

Given the overlapping modes of transmission of HIV, hepatitis B virus (HBV), and hepatitis C virus (HCV), understanding the burden and relationship of these infections is critical for an effective response. Representative data on these infections among males who inject drugs (MWID), the key high-risk population for HIV in Vietnam, are currently lacking.

METHODS

Data and stored specimens from Vietnam's 2009-2010 Integrated Biologic and Behavioral Survey, a cross-sectional study among high-risk populations, were used for this analysis. Plasma samples were tested for HIV, HBV, and HCV using commercial assays. A questionnaire was administered to provide demographic, behavior, and service-uptake information. Provincial-level analyses were conducted to profile MWID enrollees and to provide estimates on the prevalence of HIV, HBV, and HCV infection.

RESULTS

Among 3010 MWID sampled across 10 provinces, the median (range) HIV prevalence was 28.1% (1.0%-55.5%). Median prevalence for current HBV infection (HBsAg+) was 14.1% (11.7%-28.0%), for previous exposure to HBV (total anti-HBc+) was 71.4% (49.9%-83.1%), and for current or past HCV infection (HCV Ag/Ab+) was 53.8% (10.9%-80.8%). In adjusted analysis, HBsAg+ (aOR: 2.09, 1.01-4.34) and HCV Ag/Ab+ (aOR: 19.58, 13.07-29.33) status were significantly associated with HIV infection; the association with total anti-HBc+ approached significance (aOR: 1.29, 0.99-1.68).

CONCLUSION

The prevalence and association between HIV, HBV, and HCV are high among MWID in Vietnam. These findings indicate the need for integrated policies and practice that for the surveillance, prevention, screening, and treatment of both HIV and viral hepatitis among MWID in Vietnam.

Risk factors for vancomycin-resistant enterococcus bacteremia and its influence on survival after allogeneic hematopoietic cell transplantation

Vancomycin-resistant enterococcus (VRE) is a well-known infectious complication among immunocompromised patients. We performed a retrospective analysis to identify risk factors for the development of VRE bacteremia (VRE-B) within 15 months after allogeneic hematopoietic cell transplantation (alloHCT) and to determine its prognostic importance for other post-transplant outcomes. Eight hundred consecutive adult patients who underwent alloHCT for hematologic diseases from 1997 to 2011 were included. Seventy-six (10%) developed VRE-B at a median of 46 days post transplant. Year of transplant, higher HCT comorbidity score, a diagnosis of ALL, unrelated donor and umbilical cord blood donor were all significant risk factors on multivariable analysis for the development of VRE-B. Sixty-seven (88%) died within a median of 1.1 months after VRE-B, but only four (6%) of these deaths were attributable to VRE. VRE-B was significantly associated with worse OS (hazard ratio 4.28, 95% confidence interval 3.23-5.66, P<0.001) in multivariable analysis. We conclude that the incidence of VRE-B after alloHCT has increased over time and is highly associated with mortality, although not usually attributable to VRE infection. Rather than being the cause, this may be a marker for a complicated post-transplant course. Strategies to further enhance immune reconstitution post transplant and strict adherence to infection prevention measures are warranted.

Protracted haemangioblastic proliferation and differentiation in von Hippel-Lindau disease

Von Hippel-Lindau (VHL) disease is caused by germline mutation of the VHL tumour suppressor gene. Patients frequently develop multiple nervous system tumours, denominated haemangioblastomas. Analysis of affected autopsy tissues suggests that tumourigenesis propagates from developmentally arrested, embryonic cells and progresses with consistent architectural, cytological, and molecular sequences similar to haemangioblastic formation and differentiation in the embryo. In this study, we analysed 156 nervous system tumours, 139 of which had been surgically resected from 83 VHL patients. We demonstrate that large tumours consistently contain epithelioid components characteristic of haemangioblastic differentiation in comparison to small tumours that solely display a poorly differentiated, mesenchymal structure. We further show exclusive activation of HIF2alpha in both small mesenchymal tumours and the mesenchymal component of large tumours, whereas activation of HIF1alpha is associated with epithelioid structure. We also show that the MIB1 proliferative index is variably increased in the epithelioid component of large tumours, with extramedullary haematopoiesis foci within the epithelioid component at 100%. These data provide compelling evidence that nervous system tumourigenesis in VHL disease represents a protracted process of haemangioblastic proliferation and differentiation that parallels haemangioblastic formation and differentiation in the embryo.

Glycomics analysis of serum: a potential new biomarker for ovarian cancer?

We recently reported the use of matrix-assisted laser desorption ionization (MALDI) Fourier transformation mass spectrometry (FTMS) techniques to identify unique glycan markers in ovarian cancer cell lines which may be biomarkers for diagnosis of ovarian cancer. Glycan markers and CA125 levels are compared in a series of ovarian cancer patients and normal control subjects. Oligosaccharides (OS) were cleaved from the serum glycoproteins and isolated using solid phase extraction. MALDI-FTMS was then used to identify unique mass spectrometry (MS) peaks. Sensitivity, specificity, and the area under the receiver operating characteristic (ROC) curve were calculated to measure the test performance of glycan markers. Sixteen unique OS MS signals were identified in ovarian cancer patient sera. Their additive mass/charge intensities were used to determine their presence or absence. The ovarian cancer patients varied in their disease status, with initial cancer stages ranging from IC to IV. Forty-four of 48 patients had detectable OS signals, with CA125 values between 2 and 17,044. Four patients had undetectable signals and their CA125 ranged between 7 and 10. Twenty-three of 24 control subjects had no detectable glycan markers, with CA125 levels between 10 and 64. Sensitivity and specificity values were determined to be 91.6% and 95.8%, respectively. The area under the ROC curve for all 72 samples was 0.954 (95% CI: 0.896, 1.0) using the glycomics assay, which was superior to CA125 in discriminating between cases and controls. This preliminary study suggests that glycomics profiling may be useful for the detection of ovarian cancer.

Urgent endovascular revascularization for symptomatic intracranial atherosclerotic stenosis

BACKGROUND

Endovascular revascularization for intracranial atherosclerotic stenoses is being increasingly performed at major medical centers and has been reported to be technically feasible and safe. The authors report their experience with patients who underwent such a procedure for impending stroke and neurologic instability.

METHOD

All 18 patients (21 intracranial lesions) treated between 1997 and 2002 at the authors' institution with endovascular revascularization were retrospectively reviewed. Each patient had failed maximal medical therapy and was thought to be at high risk for an imminent stroke.

RESULTS

Endovascular revascularization was performed on eight distal internal carotid artery lesions, six middle cerebral artery lesions, four intracranial vertebral artery lesions, and three basilar artery lesions. Recanalization was complete in 5 arteries (Thrombolysis in Myocardial Infarction [TIMI] Grade III), partial in 14 arteries (TIMI Grade II), and complete occlusion (TIMI 0) developed in 1 artery. In a patient with a tight basilar stenosis, no angioplasty could be performed because of the inability to cross the stenosis with the guidewire. Major periprocedural complications occurred in 9 (50%) patients: intracranial hemorrhage in 3 (17%), disabling ischemic stroke in 2 (11%), and major extracranial hemorrhage in 4 (22%). Three patients died: one from intracerebral hemorrhage and two from cardiorespiratory failure.

CONCLUSIONS

Endovascular revascularization of intracranial vessels is technically feasible and may be performed successfully. However, periprocedural complication and fatality rates in neurologically unstable patients are high. The results suggest that patient selection, procedure timing, and periprocedural medical management are critical factors to reduce periprocedural morbidity and mortality.

SUB1, an Arabidopsis Ca2+-binding protein involved in cryptochrome and phytochrome coaction

Cryptochromes and phytochromes are the major photosensory receptors in plants and often regulate similar photomorphogenic responses. The molecular mechanisms underlying functional interactions of cryptochromes and phytochromes remain largely unclear. We have identified an Arabidopsis photomorphogenic mutant, sub1, which exhibits hypersensitive responses to blue light and far-red light. Genetic analyses indicate that SUB1 functions as a component of a cryptochrome signaling pathway and as a modulator of a phytochrome signaling pathway. The SUB1 gene encodes a Ca2+-binding protein that suppresses light-dependent accumulation of the transcription factor HY5.

Radiographic evidence and surgical confirmation of a saccular aneurysm on a hypoplastic duplicated A1 segment of the anterior cerebral artery: case report

OBJECTIVE AND IMPORTANCE

True duplication of the A1 segment of the anterior cerebral artery is extremely rare, as is finding a true A1 segment saccular aneurysm. We report the angiographic and surgical findings of such a case with the additional association of a hypoplastic ipsilateral M1 segment of the middle cerebral artery.

CLINICAL PRESENTATION

A 68-year-old man presented with a Hunt and Hess Grade II subarachnoid hemorrhage and symptoms of headache, nuchal rigidity, and facial paresis.

INTERVENTION

Angiographic evaluation with superselective exploration revealed a small ruptured aneurysm located on a duplicated hypoplastic A1 segment of the left anterior cerebral artery with associated middle cerebral artery stenosis and secondary early moyamoya changes. Surgical clipping of the aneurysm was performed successfully while sparing the hypoplastic A1 segment.

CONCLUSION

A1 aneurysms occurring on a duplicated anterior cerebral artery segment probably develop from a congenital weakness of the parent vessel and increased local shear stress. Superselective angiography was helpful in the preoperative planning and facilitated the decision to treat with surgical clipping instead of embolization.

Direct sequencing of RAPD fragments using 3'-extended oligonucleotide primers and dye terminator cycle-sequencing

Random amplified polymorphic DNA (RAPD) markers are used widely to develop high resolution genetic maps and for genome fingerprinting. Typically, single oligomers of approximately 10 nucleotides are used to PCR amplify characteristic RAPD marker fragments. We describe an efficient method for the direct end-sequencing of gel-purified RAPD fragments using one primer from a set of four 3'-terminal extended (A, T, C or G) oligonucleotides, identical to the RAPD primer but for the single nucleotide extension. Strand-specific DNA sequence could be independently read from each of the RAPD fragments without recourse to strand separation or fragment cloning. Informative RAPD fragments could be readily converted into mapped STS or SCAR loci using this technology. The 3'-extended primers may also be used to amplify independent genomic RAPD markers.

The Arabidopsis blue light receptor cryptochrome 2 is a nuclear protein regulated by a blue light-dependent post-transcriptional mechanism

Cryptochrome 2 is a flavin-type blue light receptor mediating floral induction in response to photoperiod and a blue light-induced hypocotyl growth inhibition. cry2 is required for the elevated expression of the flowering-time gene CO in response to long-day photoperiods, but the molecular mechanism underlying the function of cry2 is not clear. The carboxyl domain of cry2 bears a basic bipartite nuclear localization signal, and the cry2 protein was co-fractionated with the nucleus. Analysis of transgenic plants expressing a fusion protein of CRY2 and the reporter enzyme GUS (GUS-CRY2) indicated that the GUS-CRY2 fusion protein accumulated in the nucleus of transgenic plants grown in dark or light. The C-terminal domain of cry2 that contains the basic bipartite nuclear localization signal was sufficient to confer nuclear localization of the fusion protein. Phenotypic analysis of transgenic plants expressing the fusion protein GUS-CRY2 demonstrated that GUS-CRY2 acts as a functional photoreceptor in vivo, mediating the blue light-induced inhibition of hypocotyl elongation. These results strongly suggest that cry2 is a nuclear protein. Although no obvious light regulation was found for the nuclear compartmentation of GUS-CRY2 fusion protein, the abundance of GUS-CRY2 was regulated by blue light in a way similar to that of cry2.

Antagonistic actions of Arabidopsis cryptochromes and phytochrome B in the regulation of floral induction

The Arabidopsis photoreceptors cry1, cry2 and phyB are known to play roles in the regulation of flowering time, for which the molecular mechanisms remain unclear. We have previously hypothesized that phyB mediates a red-light inhibition of floral initiation and cry2 mediates a blue-light inhibition of the phyB function. Studies of the cry2/phyB double mutant provide direct evidence in support of this hypothesis. The function of cryptochromes in floral induction was further investigated using the cry2/cry1 double mutants. The cry2/cry1 double mutants showed delayed flowering in monochromatic blue light, whereas neither monogenic cry1 nor cry2 mutant exhibited late flowering in blue light. This result suggests that, in addition to the phyB-dependent function, cry2 also acts redundantly with cry1 to promote floral initiation in a phyB-independent manner. To understand how photoreceptors regulate the transition from vegetative growth to reproductive development, we examined the effect of sequential illumination by blue light and red light on the flowering time of plants. We found that there was a light-quality-sensitive phase of plant development, during which the quality of light exerts a profound influence on flowering time. After this developmental stage, which is between approximately day-1 to day-7 post germination, plants are committed to floral initiation and the quality of light has little effect on the flowering time. Mutations in either the PHYB gene or both the CRY1 and CRY2 genes resulted in the loss of the light-quality-sensitive phase manifested during floral development. The commitment time of floral transition, defined by a plant's sensitivity to light quality, coincides with the commitment time of inflorescence development revealed previously by a plant's sensitivity to light quantity - the photoperiod. Therefore, the developmental mechanism resulting in the commitment to flowering appears to be the direct target of the antagonistic actions of the photoreceptors.

Adenosine-induced cardiac pause for endovascular embolization of cerebral arteriovenous malformations: technical case report

OBJECTIVE

Extremely high flow through arteriovenous malformations (AVMs) may limit the safety and effectiveness of endovascular glue therapy. To achieve a more controlled deposition of glue, we used transient but profound systemic hypotension afforded by an intravenously administered bolus of adenosine to induce rapidly reversible high-degree atrioventricular block.

METHODS AND CASE REPORT

A patient with a large high-flow occipital AVM fed primarily by the posterior cerebral artery underwent n-butyl cyanoacrylate glue embolization. Nitroprusside-induced systemic hypotension did not adequately reduce flow through the nidus, as determined by contrast injection in the feeding artery. In a dose-escalation fashion, boluses of adenosine were administered to optimize the dose and verify that there was no flow reversal in the AVM and no other unexpected hemodynamic abnormalities by arterial pressure measurements and transcranial Doppler monitoring of the posterior cerebral artery feeding the AVM. Thereafter, 64 mg of adenosine was rapidly injected as a bolus to provide 10 to 15 seconds of systemic hypotension (approximately 20 mm Hg). Although there were conducted beats and some residual forward flow through the AVM during this time, the mean systemic and feeding artery pressures were roughly similar and remained relatively constant. A slow controlled injection of n-butyl cyanoacrylate glue was then performed, with excellent filling of the nidus.

CONCLUSION

Adenosine-induced cardiac pause may be a viable method of partial flow arrest in the treatment of cerebral AVMs. Safe, deep, and complete embolization with a permanent agent may increase the likelihood of endovascular therapy's being curative or may further improve the safety of microsurgical resection.

Recurrent abrupt occlusion after transluminal angioplasty for basilar artery stenosis: case report

OBJECTIVE AND IMPORTANCE

Angioplasty for basilar artery stenosis is often complicated by recurrent abrupt vessel closure. The clinical results can be catastrophic. In this case report, we assess the effects of intra-arterial papaverine (American Regent Laboratories Inc., Shirley, NJ) on rebound occlusion.

CLINICAL PRESENTATION

The patient presented with crescendo transient ischemic attacks from atherosclerotic narrowing of the midbasilar artery despite maximal medical treatment.

INTERVENTION

Angioplasty of the midbasilar artery was performed with serial balloon inflations. The patient was treated successfully with intra-arterial papaverine and achieved a nearly full recovery, with only mild dysarthria, by the time of the 7-month follow-up examination.

CONCLUSION

Using intra-arterial papaverine, we were able to reverse the effects of this potentially life-threatening complication of basilar artery angioplasty.

Cerebral arteriovenous malformation feeding artery aneurysms: a theoretical model of intravascular pressure changes after treatment

OBJECTIVE

A quantitative model may be used to estimate the magnitude of expected pressure changes along the vascular tree with shunt ablation and may provide information to assess the hemodynamic risk of arteriovenous malformation (AVM) treatment.

METHODS

A computer model of the cerebral circulation was applied to estimate the changes in intravascular pressure, velocity, biomechanical stress, and shear stress that might be expected from either endovascular or surgical ablation of AVMs. Two AVM sizes and two feeding artery constellations were simulated. The effect of different shunt flows on vascular pressure was modeled. In each simulation, AVMs were occluded in a stepwise fashion. The effects of systemic hypertension and hypotension in various vascular zones were also simulated.

RESULTS

As large (1000 ml/min) AVMs were occluded, the mean feeding arterial pressure increased from 18 to 68 mm Hg; the percent-occlusion at half-maximal pressure increase was 92%. For medium (500 ml/min) AVMs, feeding arterial pressure increased from 37 to 66 mm Hg; the percent-occlusion at half-maximal pressure increase was 71%. During manipulation of systemic pressure, hemodynamic changes in the circulation close to the nidus were proportionally less than changes in systemic pressure; the degree of proportionality depended on the magnitude of AVM shunt flow.

CONCLUSION

In this simulation, shunt obliteration increased pressure in the nidus and feeding arteries with little effect on the proximal circulation. The shunt provided a "buffering" effect, i.e., higher flow fistulas were exposed to smaller variations in intravascular pressure in feeding artery and nidal pressures during manipulation of systemic pressure.

Treatment of inoperable carotid aneurysms with endovascular carotid occlusion after extracranial-intracranial bypass surgery

OBJECTIVE

Hunterian ligation of the internal carotid artery (ICA) is an accepted treatment for inoperable carotid aneurysms. Preliminary extracranial-intracranial (EC-IC) bypass surgery is required in some patients. The reported incidence of thromboembolic and ischemic complications remains significant for these patients, despite a variety of advocated management strategies. We present our treatment paradigm.

METHODS

Between April 1992 and March 1997, nine patients with inoperable ICA aneurysms were treated using EC-IC bypass surgery and then permanent endovascular ICA occlusion. All of the patients except one had been selected for bypass surgery on the basis of failing results of the ICA test occlusion with hypotensive challenge. ICA occlusion was performed by endovascular means and was delayed after bypass surgery was performed by a mean of 6 days (range, 2-20 d). All patients were managed in the intensive care unit after ICA occlusion.

RESULTS

Clinical improvement was noted in all patients (mean follow-up, 21 mo; range, 3-42 mo). There were no major complications. Aneurysmal thrombosis was confirmed in all patients. Although ICA occlusion was delayed after bypass surgery, only one bypass was noted to be occluded. The occluded bypass occurred in a patient who subsequently underwent successful ICA occlusion. This patient was thought to have been improperly selected for bypass surgery.

CONCLUSION

Certain carotid aneurysms can be effectively managed with hunterian ICA ligation. After preliminary identification of patients with borderline cerebrovascular reserve as candidates for EC-IC bypass surgery, close attention to the following points may help enhance clinical outcome: 1) excellence in surgical technique for EC-IC bypass surgery, 2) occlusion of the parent vessel as close to the aneurysm neck as possible by endovascular means, and 3) judicious postoperative combination of anticoagulation, fluid, and pressure management.

Risk of spontaneous haemorrhage after diagnosis of cerebral arteriovenous malformation

BACKGROUND

A small proportion of strokes are caused by cerebral arteriovenous malformations (AVM). Treatment to prevent intracranial haemorrhage itself carries risks, and untreated AVM may in many cases have a good prognosis. We investigated the risk of subsequent symptomatic bleeding in the clinical course of AVM in patients with and without an initial haemorrhage.

METHODS

281 unselected, consecutive, prospectively enrolled patients with cerebral AVM were grouped according to their initial clinical presentation--142 presented with and 139 without haemorrhage. The frequency of AVM haemorrhages during the subsequent clinical course (before the start of endovascular, surgical, or radiation treatment) in the two groups was compared by means of Kaplan-Meier life-tables, log-rank test, and multivariate proportional-hazards regression models. Haemorrhage was defined as a clinically symptomatic event with signs of acute bleeding on computed tomography or magnetic resonance brain imaging.

FINDINGS

During mean follow-up of 8.5 months for the haemorrhage group and 11.9 months for the non-haemorrhage group, haemorrhages occurred in 18 (13%) of the former patients and in three (2%) of the latter (p=0.0002). The annual risk of haemorrhage was 17.8% and 2.2%, respectively. In the multivariate regression model, the adjusted hazard ratio for haemorrhage at initial presentation was 13.9 (95% CI 2.6-73.8; p=0.002). Deep venous drainage (hazard ratio 4.1 [1.2-14.9], p=0.029) and male sex (9.2 [2.1-41.3], p=0.004) were also significantly associated with subsequent haemorrhage, but no significant association was found for age or AVM size. The annual rate of spontaneous haemorrhage was 32.6% for men and 10.4% for women in the haemorrhage group compared with 3.3% for men and 1.3% for women in the non-haemorrhage group. Among patients with haemorrhage at initial presentation, the risk of haemorrhage fell from 32.9% in year 1 to 11.3% in subsequent years (34.2% to 31.0% in men; 31.1% to 5.5% in women).

INTERPRETATION

In AVM, patients initially presenting with haemorrhage have a higher risk of subsequent bleeding than those presenting with other symptoms. The risk is higher in men than in women.

Intra-arterial nitrovasodilators do not increase cerebral blood flow in angiographically normal territories of arteriovenous malformation patients

BACKGROUND AND PURPOSE

The mechanism of adaptation to chronic cerebral hypotension in normal brain adjacent to cerebral arteriovenous malformations (AVMs) is unknown. To clarify these mechanisms, we performed cerebral blood flow (CBF) studies in structurally and functionally normal vascular territories during 53 distal cerebral angiographic procedures in 37 patients with AVMs.

METHODS

CBF was measured using the superselective intra-arterial 133Xe method before and after a 3-minute infusion of either verapamil (1 mg.min-1, n = 23), acetylcholine (1.33 micrograms.kg-1.min-1, n = 7), nitroprusside (0.5 microgram.kg-1.min-1, n = 16) or nitroglycerin (0.5 microgram.kg-1.min-1, n = 7).

RESULTS

Mean +/- SD systemic (76 +/- 13 mm Hg) and distal cerebral arterial (55 +/- 16 mm Hg; range, 20 to 97 mm Hg) pressures were not different among groups. Verapamil increased CBF (45 +/- 12 to 65 +/- 21 mL.100 g-1.min-1, P < .001). There was no effect of acetylcholine (no change [46 +/- 9 to 46 +/- 9 mL.100 g-1.min-1], NS) or nitroglycerin (36 +/- 14 to 36 +/- 13 mL.100 g-1.min-1, NS). Nitroprusside decreased CBF (40 +/- 12 to 31 +/- 11 mL.100 g-1.min-1, P < .001). The percent change in CBF after drug administration was proportional to cerebral arterial pressure for verapamil only (r = .57, P = .0051).

CONCLUSIONS

When infused intra-arterially in clinically relevant doses in both hypotensive and normotensive normal vascular territories remote from an AVM nidus, calcium channel blockade caused vasodilation, but there was an absence of response to nitric oxide-mediated vasodilators. These data suggest that (1) the nitric oxide pathway probably is not involved in the adaptation to chronic cerebral hypotension in AVM patients and (2) if our findings in vessels remote from or contralateral to the AVM are applicable to vessels of patients with other forms of cerebrovascular disease, clinically relevant doses of intra-arterial nitrovasodilators may not be useful in the manipulation of cerebrovascular resistance.

Strain differences in tissue repair response to 1,2-dichlorobenzene

Fischer 344 (F344) rats are reportedly 75-fold more sensitive than Sprague Dawley (S-D) rats to 1,2-dichlorobenzene (o-DCB) hepatotoxicity. Lethality studies were conducted since no information was available regarding the ultimate consequence of this sensitivity in terms of animal survival in the two strains. LD50S for o-DCB (1.66 ml/kg and 1.76 ml/kg in male F344 and S-D rats, respectively) did not differ. Several studies have shown the importance of tissue repair on animal survival following exposure to toxic chemicals. The objective of this study was to investigate if differential rates of cell division and tissue repair might explain the lack of difference in LD50 dose between the two strains despite higher hepatotoxic injury in F344 rats. Age-matched male S-D and F344 rats were administered o-DCB (0.2, 0.6, 1.2 ml/kg, i.p.); injury and tissue repair occurring as two dynamic but opposing events were measured over time. Liver injury was assessed by measuring plasma alanine aminotransferase (ALT) and sorbitol dehydrogenase (SDH) activities and by liver histopathology. Higher plasma ALT elevations were observed in F344 rats following administration of 0.2 and 0.6 ml o-DCB/kg. Using SDH as a marker of liver injury, the strain difference was evident only at 0.2 ml o-DCB/kg. Liver regeneration was estimated by 3H-thymidine incorporation into hepatonuclear DNA and via proliferating cell nuclear antigen (PCNA) assay. Prompt and significantly higher hepatocellular regeneration beginning at 36 h was evident in F344 rats following administration of 0.2 and 0.6 ml o-DCB/kg. The significantly higher depletion of hepatic glycogen observed in F344 rats following administration of 0.2 and 0.6 ml o-DCB/kg occurred without significant changes in plasma glucose and is consistent with highly stimulated tissue repair seen in these rats at the corresponding doses. However, increasing the dose further to 1.2 ml o-DCB/kg results in a delayed (S-phase synthesis begins at 48 h) and diminished response to o-DCB. These findings suggest that a significantly higher rate of tissue repair in F344 rats helps them overcome higher liver injury inflicted by o-DCB. This differential in tissue repair in the two strains may play a vital role in equalizing the ultimate outcome of toxicity in the two strains.

Varicella-zoster virus DNA in CSF and arteries in delayed contralateral hemiplegia: evidence for viral invasion of cerebral arteries

A 78-year-old woman presented with a right basal ganglia infarct 6 weeks after a left herpes zoster ophthalmicus. MR angiography showed focal segmental stenosis of the proximal segments of the anterior, middle, and posterior cerebral arteries. Varicella DNA was detected in the CSF by polymerase chain reaction (PCR). Treated with dexamethasone and acyclovir without improvement, she died 1 month later. There was focal endarteritis in the left anterior, middle, and posterior cerebral arteries at autopsy. Varicella DNA was detected by PCR of extracts from these vessels but not from the arteries on the right side. This study provides further evidence that the vasculopathy after herpes zoster ophthalmicus results from direct viral invasion of the vessel wall.

The negative angiogram in subarachnoid haemorrhage

Our purpose was to review the incidence of negative cerebral panangiography in acute nontraumatic subarachnoid haemorrhage (SAH); to document the amount and distribution of subarachnoid blood on CT and determine its relationship to findings on repeat angiography; and to study the outcome of these patients from the time of presentation to hospital discharge. From 1983 to 1992, 295 patients underwent cerebral angiography for acute SAH at our institution. The CT, angiographic and MRI findings and clinical course of patients with initially negative angiograms were reviewed retrospectively. The overall incidence of negative cerebral panangiography was 31% (92/295). An aneurysm was disclosed on a second angiogram in 4 cases, and on a third angiogram in 1, giving a total false negative rate of 5%. In 55% of cases, only a small amount of SAH was present on CT. The distribution of the subarachnoid blood was nonspecific and resembled the pattern seen in aneurysmal SAH. Ninety-four percent of the patients presented in Hunt-Hess grades I and II. The complications of conservative treatment were few: a rebleed rate of 4%, delayed cerebral ischemia in 4%, cerebral infarcts in 8% and hydrocephalus requiring shunting in 3%. On discharge, 93% of patients had recovered completely and the others were left with moderate disability. There were two deaths related to massive rebleeding. Patients with perimesencephalic SAH (35%) fared particularly well; none developed complications during their hospital stay and repeat angiograms never revealed an underlying aneurysm. In such cases, further angiographic investigations do not seem warranted.

Tophaceous gout of the lumbar spine mimicking an epidural abscess: MR features

We present the MR findings in a case of tophaceous gout of the lumbar spine with cauda equina compression, mimicking an epidural abscess. The diagnosis was clinically unsuspected and confirmed at laminectomy. Tophus material in the paraspinal soft tissues appeared intermediate in signal intensity and showed heterogeneous contrast enhancement.

Magnetic resonance imaging of lateral ventricular tumours

The authors review their experience with magnetic resonance imaging (MRI) of giant lateral ventricular tumours, placing special emphasis on the imaging features that aid in the differential diagnosis. The tumours illustrated include astrocytoma, oligodendroglioma, neurocytoma, subependymoma, metastatic lesions and subependymal giant cell astrocytoma. Because of their large size, most of these lesions cause hydrocephalus. The presence of associated edema indicates direct brain invasion or a higher grade of tumour differentiation. The degree and pattern of contrast enhancement, as well as the signal characteristics before administration of contrast agent, are nonspecific. The location of the tumour within the lateral ventricles and the patient's age are the most helpful diagnostic clues. Giant lateral ventricular tumours are uncommon, and the patients usually come to clinical attention with symptoms related to increased intracranial pressure. MRI assists in surgical planning by defining the exact location of the lesion and its relation to adjacent structures. Although the signal characteristics and patterns of contrast enhancement are nonspecific, preoperative diagnosis is possible in most cases if the imaging findings are correlated with the patient's age and the specific location of the tumour within the lateral ventricles.

A learned odor evokes an enhanced Fos-like glomerular response in the olfactory bulb of young rats

Young rats exposed to peppermint odor and reinforcing tactile stimulation from postnatal days (PND) 1-18 increase their preference for that odor relative to controls. This early olfactory memory is accompanied by an 80% increase in the density of glomerular-layer cells displaying Fos-like immunoreactivity in response to the learned odor on PND 19. The difference is observed in midlateral portions of the olfactory bulb that align with foci of 2-deoxyglucose (2-DG) uptake in adjacent sections. Trained and control animals are not different in the Fos-like response of juxtaglomerular cells within ventrolateral 2-DG foci. Ratios of midlateral/ventrolateral response differ significantly between trained and control animals and include differences among cells of three staining intensities. These ratios are correlated with ratios of 2-DG uptake (midlateral/ventrolateral foci), which also differ significantly between trained and control rats. Juxtaglomerular cells associated with 2-DG foci also express Egr-1-like immunoreactivity. However, the midlateral Egr-1 response does not differ between trained and control rats. These results show that early memories can be associated with an increased Fos-like response in a primary sensory area of the CNS. They also suggest that only specific regions within the olfactory bulb are modified following the learning of a given odor in early life.