Heterologous expression of influenza haemagglutinin leads to early and transient activation of the unfolded protein response in Nicotiana benthamiana

The unfolded protein response (UPR) allows cells to cope with endoplasmic reticulum (ER) stress induced by accumulation of misfolded proteins in the ER. Due to its sensitivity to Agrobacterium tumefaciens, the model plant Nicotiana benthamiana is widely employed for transient expression of recombinant proteins of biopharmaceutical interest, including antibodies and virus surface proteins used for vaccine production. As such, study of the plant UPR is of practical significance, since enforced expression of complex secreted proteins often results in ER stress. After 6 days of expression, we recently reported that influenza haemagglutinin H5 induces accumulation of UPR proteins. Since up-regulation of corresponding UPR genes was not detected at this time, accumulation of UPR proteins was hypothesized to be independent of transcriptional induction, or associated with early but transient UPR gene up-regulation. Using time course sampling, we here show that H5 expression does result in early and transient activation of the UPR, as inferred from unconventional splicing of NbbZIP60 transcripts and induction of UPR genes with varied functions. Transient nature of H5-induced UPR suggests that this response was sufficient to cope with ER stress provoked by expression of the secreted protein, as opposed to an antibody that triggered stronger and more sustained UPR activation. As up-regulation of defence genes responding to H5 expression was detected after the peak of UPR activation and correlated with high increase in H5 protein accumulation, we hypothesize that these immune responses, rather than the UPR, were responsible for onset of the necrotic symptoms on H5-expressing leaves.

Molecular responses of agroinfiltrated Nicotiana benthamiana leaves expressing suppressor of silencing P19 and influenza virus-like particles

The production of influenza vaccines in plants is achieved through transient expression of viral hemagglutinins (HAs), a process mediated by the bacterial vector Agrobacterium tumefaciens. HA proteins are then produced and matured through the secretory pathway of plant cells, before being trafficked to the plasma membrane where they induce formation of virus-like particles (VLPs). Production of VLPs unavoidably impacts plant cells, as do viral suppressors of RNA silencing (VSRs) that are co-expressed to increase recombinant protein yields. However, little information is available on host molecular responses to foreign protein expression. This work provides a comprehensive overview of molecular changes occurring in Nicotiana benthamiana leaf cells transiently expressing the VSR P19, or co-expressing P19 and an influenza HA. Our data identifies general responses to Agrobacterium-mediated expression of foreign proteins, including shutdown of chloroplast gene expression, activation of oxidative stress responses and reinforcement of the plant cell wall through lignification. Our results also indicate that P19 expression promotes salicylic acid (SA) signalling, a process dampened by co-expression of the HA protein. While reducing P19 level, HA expression also induces specific signatures, with effects on lipid metabolism, lipid distribution within membranes and oxylipin-related signalling. When producing VLPs, dampening of P19 responses thus likely results from lower expression of the VSR, crosstalk between SA and oxylipin pathways, or a combination of both outcomes. Consistent with the upregulation of oxidative stress responses, we finally show that reduction of oxidative stress damage through exogenous application of ascorbic acid improves plant biomass quality during production of VLPs.

Stent-Assisted Coiling in the Treatment of Unruptured Intracranial Aneurysms: A Randomized Clinical Trial

BACKGROUND AND PURPOSE

Stent-assisted coiling may improve angiographic results of endovascular treatment of unruptured intracranial aneurysms compared with coiling alone, but this has never been shown in a randomized trial.

MATERIALS AND METHODS

The Stenting in the Treatment of Aneurysm Trial was an investigator-led, parallel, randomized (1:1) trial conducted in 4 university hospitals. Patients with intracranial aneurysms at risk of recurrence, defined as large aneurysms (≥10 mm), postcoiling recurrent aneurysms, or small aneurysms with a wide neck (≥4 mm), were randomly allocated to stent-assisted coiling or coiling alone. The composite primary efficacy outcome was "treatment failure," defined as initial failure to treat the aneurysm; aneurysm rupture or retreatment during follow-up; death or dependency (mRS > 2); or an angiographic residual aneurysm adjudicated by an independent core laboratory at 12 months. The primary hypothesis (revised for slow accrual) was that stent-assisted coiling would decrease treatment failures from 33% to 15%, requiring 200 patients. Primary analyses were intent to treat.

RESULTS

Of 205 patients recruited between 2011 and 2021, ninety-four were allocated to stent-assisted coiling and 111 to coiling alone. The primary outcome, ascertainable in 203 patients, was reached in 28/93 patients allocated to stent-assisted coiling (30.1%; 95% CI, 21.2%-40.6%) compared with 30/110 (27.3%; 95% CI, 19.4%-36.7%) allocated to coiling alone (relative risk = 1.10; 95% CI, 0.7-1.7; P  = .66). Poor clinical outcomes (mRS >2) occurred in 8/94 patients allocated to stent-assisted coiling (8.5%; 95% CI, 4.0%-16.6%) compared with 6/111 (5.4%; 95% CI, 2.2%-11.9%) allocated to coiling alone (relative risk = 1.6; 95% CI, 0.6%-4.4%; P  = .38).

CONCLUSIONS

The STAT trial did not show stent-assisted coiling to be superior to coiling alone for wide-neck, large, or recurrent unruptured aneurysms.

Association between Early Ischemic Changes and Collaterals in Acute Stroke: A Retrospective Study

BACKGROUND AND PURPOSE

The quality of leptomeningeal collaterals may influence the speed of infarct progression in acute stroke. Our main objective was to evaluate the association of leptomeningeal collateral score and its interaction with time with ischemic changes on CT in patients with acute stroke.

MATERIALS AND METHODS

Adult patients with acute stroke symptoms and anterior circulation large-vessel occlusion on CTA from 2015 to 2019 were included. Routinely performed NCCT and multiphase CTA were reviewed to assess ASPECTS and the leptomeningeal collateral score. We built multivariate regression models to assess the association between leptomeningeal collateral score and its interaction with time and ASPECTS. Performance measures to predict poor ASPECTS at different time thresholds (identified with receiver operating characteristic curve analysis) were estimated in a subgroup of patients with poor leptomeningeal collateral scores.

RESULTS

Leptomeningeal collateral scores 0-1 were associated with lower ASPECTS, and the model with dichotomized and trichotomized leptomeningeal collateral score showed a significant multiplicative interaction between time and the leptomeningeal collateral score. The negative predictive value for poor ASPECTS was >0.9 for at least the first 3 hours from stroke onset to imaging, and the positive predictive value was <0.5 for every time threshold tested in the subgroup of patients with leptomeningeal collateral scores 0-3.

CONCLUSIONS

Poor (0-1) leptomeningeal collateral scores were associated with lower ASPECTS, and an increase in time has a multiplicative interaction with the leptomeningeal collateral score on ASPECTS.

A45 INFLIXIMAB IN COMBINATION WITH AN IMMUNOMODULATOR IS ASSOCIATED WITH AN ATTENUATED ANTIBODY RESPONSE TO BNT162B2 SARS-COV-2 VACCINE IN PEDIATRIC INFLAMMATORY BOWEL DISEASE PATIENTS

Background

Adult data have shown that Infliximab (IFX) impairs the antibody response to a single dose of the mRNA-BNT162b2 SARS-CoV-2 vaccine in patients with inflammatory bowel disease (IBD). The true impact of IFX on SARS-CoV-2 vaccine efficacy in pediatric IBD (PIBD) patients is unknown.

Aims

To evaluate the humoral immune response to the BNT162b2 SARS-CoV-2 in PIBD patients treated with anti-tumor necrosis factor (TNF) therapy.

Methods

PIBD patients treated with anti-TNF therapy either alone or in combination with an immunomodulator, who received at least one dose of the BNT162b2 SARS-CoV-2 vaccine, were prospectively enrolled from 1st June 2021 at BC Children’s Hospital. Serum antibody levels for [spike (S) protein and receptor-binding domain (RBD)] were determined at baseline and 28 days after their first and second vaccine doses. Antibody responses were assessed using multiplex serology IgG assay against four SARS-CoV-2 antigens: S-protein, RBD, N-terminal domain (NTD) and N-protein using the SARS-CoV-2 Panel 2 (Meso Scale Diagnostics).

Results

Forty-two PIBD patients received a single dose of BNT162b2 (median age 14.5yrs (IQR 14–16); 43% female; 79% crohn’s disease, 21%, ulcerative colitis). Of those on IFX monotherapy (43%), both S-protein and RBD antibody concentrations 28 days post BNT162b2 were comparable to healthy adult controls (n=20, median age: 36yrs (IQR 29–40); 65% female) who had received one dose of BNT162b2 (p = 0.07) [Figure 1]. In PIBD patients on IFX in combination with either azathioprine or methotrexate (57%) both S-protein and RBD antibody concentrations were significantly lower than controls after 1 dose of BNT162b2 (p = 0.0003) [Figure 1].

In the PIBD cohort (n=27) who received 2 doses of BNT162b2 vaccine (median age 14yrs (IQR 14–16);41% female;63% crohn’s disease, 37% ulcerative colitis; median interval between doses 56 days (IQR 22–105)), there was no difference in antibody response after 2 doses compared to healthy adult controls (n=14, median age: 44 years (IQR 36–51); 29% female) whether they were on IFX monotherapy (41%) or in combination with an immunomodulator (59%) [Figure 1].

Conclusions

We provide evidence of an attenuated antibody response in PIBD patients on IFX in combination with an immunomodulator after a single dose of BNT162b2. However, our data show a robust antibody response in PIBD patients, despite their infliximab treatment, after two doses of BNT162b2 vaccine. Our results are consistent with adult IBD data and highlight the importance of administering the second vaccine dose to achieve protection in this vulnerable patient population. Long-term follow-up to assess longevity of vaccine protection is warranted.

Funding Agencies

None

A1 USING HUMAN NEONATAL ORGANOIDS TO EXPLORE GUT-IMMUNE SYSTEM INTERACTIONS OF THE NEONATAL INTESTINE

Background

Necrotizing Enterocolitis (NEC) affects around 10% of preterm babies and is one of the leading causes of death for newborns. NEC is characterized by exaggerated inflammation of the intestinal mucosa, possibly triggered by aberrant exposure to gut microbes, leading to hypoxic conditions and the death of intestinal tissues. It has been hypothesized that NEC develops when the immature intestine (epithelium and immune system) is unable to properly balance these new microbial interactions. To date, NEC is poorly understood and due to the difficulty of modeling the human neonatal intestine, few therapeutic options are available.

Intestinal epithelial cells (IEC) are important players in promoting beneficial host-microbe interactions in the gut, being the primary barrier that separates the host’s mucosal immune system from luminal microbiota, as well as key players in mediating signaling between microbes and the host. Based on their location, IEC are also subject to injury associated with maladaptive immune responses against gut microbes. Many studies have shown that immune cells (such as T helper 17 cells) interact with IEC to promote gut health and function. These interactions include educating IEC on how to respond to, and fight pathogenic microbes, yet also remain tolerant to commensal microbes.

Aims

This project seeks to develop an in vitro human neonatal intestinal organoid model to study developmental changes in IEC and their functional interactions with neonatal Th17 cells.

Methods

3D organoids were established from human neonatal intestinal biopsies and then co-cultured with the supernatant of differentiated Th17 cells or with recombinant cytokines, IL-17 and IL-22. Changes in barrier function, cell proliferation, production of mucins and anti-microbial peptides (AMP) were analyzed by qPCR and immunostaining.

Results

Using 3D neonatal organoids we observed that the supernatants from neonatal Th17 cells (containing IL-17, IL-22 etc.) promoted the proliferation, differentiation and barrier function of the neonatal epithelium. By using specific recombinant cytokine (IL22, IL17) and neutralizing IL-22 antibodies in parallel, we demonstrated that the high levels of IL-22 produced by neonatal Th17 cells specifically induced proliferation of IEC, AMP and mucus production as compared to control media treated organoids, as shown by increases in Ki67, Reg3γ and Muc2 markers.

Conclusions

This experimental model mimicking the neonatal intestinal environment can be used to study interactions between neonatal IEC and immune cells. Our findings can provide clinically relevant information and clues to how developmental changes in the newborn intestine can influence susceptibility to NEC while demonstrating our development of a simple, yet accurate and clinically applicable model of the neonatal gut.

Funding Agencies

CAG, CIHRBCCHRI, CCC, C.H.I.L.D. Fdn

Wing morphing allows gulls to modulate static pitch stability during gliding

A gliding bird's ability to stabilize its flight path is as critical as its ability to produce sufficient lift. In flight, birds often morph the shape of their wings, but the consequences of avian wing morphing on flight stability are not well understood. Here, we investigate how morphing the gull elbow joint in gliding flight affects their static pitch stability. First, we combined observations of freely gliding gulls and measurements from gull wing cadavers to identify the wing configurations used during gliding flight. These measurements revealed that, as wind speed and gusts increased, gulls flexed their elbows to adopt wing shapes characterized by increased spanwise camber. To determine the static pitch stability characteristics of these wing shapes, we prepared gull wings over the anatomical elbow range and measured the developed pitching moments in a wind tunnel. Wings prepared with extended elbow angles had low spanwise camber and high passive stability, meaning that mild perturbations could be negated without active control. Wings with flexed elbow angles had increased spanwise camber and reduced static pitch stability. Collectively, these results demonstrate that gliding gulls can transition across a broad range of static pitch stability characteristics using the motion of a single joint angle.

Does Increasing Packing Density Using Larger Caliber Coils Improve Angiographic Results of Embolization of Intracranial Aneurysms at 1 Year: A Randomized Trial

BACKGROUND AND PURPOSE

The impact of increased aneurysm packing density on angiographic outcomes has not been studied in a randomized trial. We sought to determine the potential for larger caliber coils to achieve higher packing densities and to improve the angiographic results of embolization of intracranial aneurysms at 1 year.

MATERIALS AND METHODS

Does Embolization with Larger Coils Lead to Better Treatment of Aneurysms (DELTA) was an investigator-initiated multicenter prospective, parallel, randomized, controlled clinical trial. Patients had 4- to 12-mm unruptured aneurysms. Treatment allocation to either 15- (experimental) or 10-caliber coils (control group) was randomized 1:1 using a Web-based platform. The primary efficacy outcome was a major recurrence or a residual aneurysm at follow-up angiography at 12 ± 2 months adjudicated by an independent core lab blinded to the treatment allocation. Secondary outcomes included indices of treatment success and standard safety outcomes. Recruitment of 564 patients was judged necessary to show a decrease in poor outcomes from 33% to 20% with 15-caliber coils.

RESULTS

Funding was interrupted and the trial was stopped after 210 patients were recruited between November 2013 and June 2017. On an intent-to-treat analysis, the primary outcome was reached in 37 patients allocated to 15-caliber coils and 36 patients allocated to 10-caliber coils (OR = 0.931; 95% CI, 0.528-1.644; P = .885). Safety and other clinical outcomes were similar. The 15-caliber coil group had a higher mean packing density (37.0% versus 26.9%, P = .0001). Packing density had no effect on the primary outcome when adjusted for initial angiographic results (OR = 1.001; 95% CI, 0.981-1.022; P = .879).

CONCLUSIONS

Coiling of aneurysms randomized to 15-caliber coils achieved higher packing densities compared with 10-caliber coils, but this had no impact on the angiographic outcomes at 1 year, which were primarily driven by aneurysm size and initial angiographic results.

Recombinant protein susceptibility to proteolysis in the plant cell secretory pathway is pH-dependent

Cellular engineering approaches have been proposed to mitigate unintended proteolysis in plant protein biofactories, involving the design of protease activity-depleted environments by gene silencing or in situ inactivation with accessory protease inhibitors. Here, we assessed the impact of influenza virus M2 proton channel on host protease activities and recombinant protein processing in the cell secretory pathway of Nicotiana benthamiana leaves. Transient co-expression assays with M2 and GFP variant pHluorin were first conducted to illustrate the potential of proton export from the Golgi lumen to promote recombinant protein yield. A fusion protein-based system involving protease-sensitive peptide linkers to attach inactive variants of tomato cystatin SlCYS8 was then designed to relate the effects of M2 on protein levels with altered protease activities in situ. Secreted versions of the cystatin fusions transiently expressed in leaf tissue showed variable 'fusion to free cystatin' cleavage ratios, in line with the occurrence of protease forms differentially active against the peptide linkers in the secretory pathway. Variable ratios were also observed for the fusions co-expressed with M2, but the extent of fusion cleavage was changed for several fusions, positively or negatively, as a result of pH increase in the Golgi. These data indicating a remodelling of endogenous protease activities upon M2 expression confirm that the stability of recombinant proteins in the plant cell secretory pathway is pH-dependent. They suggest, in practice, the potential of M2 proton channel to modulate the stability of protease-susceptible secreted proteins in planta via a pH-related, indirect effect on host resident proteases.

Canadian Stroke Best Practice Recommendations for Acute Stroke Management: Prehospital, Emergency Department, and Acute Inpatient Stroke Care, 6th Edition, Update 2018

The 2018 update of the Canadian Stroke Best Practice Recommendations for Acute Stroke Management, 6th edition, is a comprehensive summary of current evidence-based recommendations, appropriate for use by healthcare providers and system planners caring for persons with very recent symptoms of acute stroke or transient ischemic attack. The recommendations are intended for use by a interdisciplinary team of clinicians across a wide range of settings and highlight key elements involved in prehospital and Emergency Department care, acute treatments for ischemic stroke, and acute inpatient care. The most notable changes included in this 6th edition are the renaming of the module and its integration of the formerly separate modules on prehospital and emergency care and acute inpatient stroke care. The new module, Acute Stroke Management: Prehospital, Emergency Department, and Acute Inpatient Stroke Care is now a single, comprehensive module addressing the most important aspects of acute stroke care delivery. Other notable changes include the removal of two sections related to the emergency management of intracerebral hemorrhage and subarachnoid hemorrhage. These topics are covered in a new, dedicated module, to be released later this year. The most significant recommendation updates are for neuroimaging; the extension of the time window for endovascular thrombectomy treatment out to 24 h; considerations for treating a highly selected group of people with stroke of unknown time of onset; and recommendations for dual antiplatelet therapy for a limited duration after acute minor ischemic stroke and transient ischemic attack. This module also emphasizes the need for increased public and healthcare provider’s recognition of the signs of stroke and immediate actions to take; the important expanding role of paramedics and all emergency medical services personnel; arriving at a stroke-enabled Emergency Department without delay; and launching local healthcare institution code stroke protocols. Revisions have also been made to the recommendations for the triage and assessment of risk of recurrent stroke after transient ischemic attack/minor stroke and suggested urgency levels for investigations and initiation of management strategies. The goal of this updated guideline is to optimize stroke care across Canada, by reducing practice variations and reducing the gap between current knowledge and clinical practice.

Predictors and timing of hypotension and bradycardia after carotid artery stenting

BACKGROUND AND PURPOSE

Hypotension and bradycardia are common in carotid artery stenting (CAS) and are particularly worrisome in the high risk patient who is typically referred for CAS. The purpose of this work was to assess the incidence and predictors of hypotension and bradycardia and the risk of their delayed occurrence after CAS.

MATERIALS AND METHODS

A total of 53 men and 40 women (median age, 71 years) with symptomatic (57%) or asymptomatic (42%) carotid artery stenosis had CAS performed in our institution between December 2002 and January 2007. Patient vital sign records for the 12 hours post-CAS were analyzed. The relative decrease of blood pressure and pulse rate were used as primary end points, and the requirement of pressor or anticholinergic drugs was used as a surrogate end point. Significant predictors of hypotension and bradycardia were analyzed with a logistic regression model. Cumulative freedom from hypotension and bradycardia was calculated by using the Kaplan-Meier method. Negative predictive value (NPV) of screening for early hypotension and bradycardia was determined.

RESULTS

The incidence of hypotension, bradycardia, and both was 14%, 23%, and 15%, respectively. Drug intervention was required in 45 patients (48%). Asymptomatic stenosis was an independent predictor of hypotension and bradycardia. Stenosis proximity to the bifurcation and dilation percentage were independent predictors of the drug intervention requirement. Seven patients (8%) had new onset of hypotension or bradycardia later than 6 hours post-CAS. The NPV of early hypotension and bradycardia was 97% and 93%, respectively.

CONCLUSION

In this retrospective study, the risk of hypotension or bradycardia after CAS is significantly influenced by the degree of dilation performed, and the risk of their delayed occurrence may justify a minimum of 12 hours postprocedural vital sign monitoring.

Microelectronic retinal prosthesis: III. a new method for fabrication of high-density hermetic feedthroughs

Therapeutic, electronic medical implants used in auditory, visual, functional, and behavioral neuroprosthesis often are required to maintain their function for the remaining lifetime of the implantee. This requirement presents a substantial engineering obstacle that has previously limited the practical upper quantity of electrodes, or other signal carrying channels such devices may possess. Hermetic encapsulation of any implanted electronics and the tendency of this encapsulation to leak is a well-known problem for biomedical engineers. Each "hardwired" signal required by, or elicited from, the implant must pass through the encapsulation without breaching hermeticity. The present paper describes a method of fabrication of hermetic feedthroughs (<2 x 10(-9) std cc He/s) comprising materials with superior biological compatibility characteristics and able to accommodate relatively high numbers of signal carrying channels relative to existing methods, while allowing this to occur within small areas.

Randomised controlled trial comparing two methods of acetabular cup positioning during total hip arthroplasty

BACKGROUND

Acetabular cup positioning is an important technical aspect in total hip arthroplasty. Most surgeons estimate cup abduction angle during surgery with the insertion rod position according to the patient's body anatomical landmarks or other reference points in the operating room. High acetabular component abduction angle is associated with an increased risk of dislocation, premature polyethylene wear and osteolysis.

METHOD

To evaluate the potential benefits of a new technique for vertical acetabular cup positioning, 100 acetabular cups were randomised to be inserted with or without an inclinometer. Abduction angles were measured on postoperative radiographs by 2 evaluators blind to the treatment group.

RESULTS

Of the cups, 57% (27/47) were positioned within the desirable abduction angle range of 40-49 with the inclinometer, compared with 50% (27/53) by visuospatial perception (p=0.454). The proportion of cups positioned outside a safe angle range of 30-55 was low in both groups: 6% (3/47) for the inclinometer group versus 4% (2/53) for the visuospatial perception group (p=0.536).

CONCLUSION

The use of an inclinometer did not significantly improve the acetabular cup abduction angle obtained by our group of surgeons when compared with visuospatial perception. Newer techniques such as navigation may be useful in further optimising cup positioning and reducing the outliers.

Power law of decaying homogeneous isotropic turbulence at low Reynolds number

We focus on an estimate of the decay exponent (m) in the initial period of decay of homogeneous isotropic turbulence at low Taylor microscale Reynolds number R lambda (approximately equal to 20-50). Lattice Boltzmann simulations in a periodic box of 256(3) points are performed and compared with measurements in grid turbulence at similar R lambda. Good agreement is found between measured and calculated energy spectra. The exponent m is estimated in three different ways: from the decay of the turbulent kinetic energy, the decay of the mean energy dissipation rate, and the rate of growth of the Taylor microscale. Although all estimates are close, as prescribed by theory, that from the Taylor microscale has the largest variability. It is then suggested that the virtual origin for the decay rate be determined from the Taylor microscale, but the actual value of m be estimated from the decay rate of the kinetic energy. The dependence of m on R lambda(0) (the value of R lambda at the beginning of the simulation) is also analyzed, using the present data as well as data from the literature. The results confirmed that m approaches 1, as R lambda(0) increases.

A new generation of artificial ligaments in reconstruction of the anterior cruciate ligament. Two-year follow-up of a randomised trial

We have undertaken a randomised clinical trial comparing two methods of reconstruction of the anterior cruciate ligament in patients with chronic instability. We used an ipsilateral bone-patellar-tendon-bone autograft in 27 patients and the Ligament Advancement Reinforcement System (LARS) artificial ligament in 26. Assessment before and at two, six, 12 and 24 months after surgery, included the history, physical examination, a modified International Knee Documentation Committee (IKDC) score, the Tegner score, the Knee Injury and Osteoarthritis Outcome Score (KOOS) and instrumented laxity testing. There were no cases of reactive synovitis or of infection of the knee, and there was no difference regarding the failure rate between the two groups. The IKDC showed no significant differences between the two groups at any stage of the follow-up. The KOOS evaluation showed consistently better results in all subscales for the LARS group during the first year of follow-up. After 24 months these differences were no longer evident. Instrument-tested laxity was greater in the LARS group at all stages of follow-up, but the differences were not significant at 24 months. Our findings suggest that at follow-up at 24 months the LARS ligament seems to be a satisfactory treatment option, especially when an early return to high levels of activity is demanded.

A new generation of artificial ligaments in reconstruction of the anterior cruciate ligament

We have undertaken a randomized clinical trial comparing two methods of reconstruction of the anterior cruciate ligament in patients with chronic instability. We used an ipsilateral bone-patellar-tendon-bone autograft in 27 patients and the Ligament Advancement Reinforcement System (LARS) artificial ligament in 26. Assessment before and at two, six, 12 and 24 months after surgery, included the history, physical examination, a modified International Knee Documentation Committee (IKDC) score, the Tegner score, the Knee Injury and Osteoarthritis Outcome Score (KOOS) and instrumented laxity testing.

There were no cases of reactive synovitis or of infection of the knee, and there was no difference regarding the failure rate between the two groups. The IKDC showed no significant differences between the two groups at any stage of the follow-up. The KOOS evaluation showed consistently better results in all subscales for the LARS group during the first year of follow-up. After 24 months these differences were no longer evident. Instrument-tested laxity was greater in the LARS group at all stages of follow-up, but the differences were not significant at 24 months.

Our findings suggest that at follow-up at 24 months the LARS ligament seems to be a satisfactory treatment option, especially when an early return to high levels of activity is demanded.

A what-and-where fusion neural network for recognition and tracking of multiple radar emitters

A neural network recognition and tracking system is proposed for classification of radar pulses in autonomous Electronic Support Measure systems. Radar type information is considered with position-specific information from active emitters in a scene. Type-specific parameters of the input pulse stream are fed to a neural network classifier trained on samples of data collected in the field. Meanwhile, a clustering algorithm is used to separate pulses from different emitters according to position-specific parameters of the input pulse stream. Classifier responses corresponding to different emitters are separated into tracks, or trajectories, one per active emitter, allowing for more accurate identification of radar types based on multiple views of emitter data along each emitter trajectory. Such a What-and-Where fusion strategy is motivated by a similar subdivision of labor in the brain. The fuzzy ARTMAP neural network is used to classify streams of pulses according to radar type using their functional parameters. Simulation results obtained with a radar pulse data set indicate that fuzzy ARTMAP compares favorably to several other approaches when performance is measured in terms of accuracy and computational complexity. Incorporation into fuzzy ARTMAP of negative match tracking (from ARTMAP-IC) facilitated convergence during training with this data set. Other modifications improved classification of data that include missing input pattern components and missing training classes. Fuzzy ARTMAP was combined with a bank of Kalman filters to group pulses transmitted from different emitters based on their position-specific parameters, and with a module to accumulate evidence from fuzzy ARTMAP responses corresponding to the track defined for each emitter. Simulation results demonstrate that the system provides a high level of performance on complex, incomplete and overlapping radar data.

Correlation between patients' satisfaction and objective measurement of knee stability after ACL reconstruction using a patellar tendon autograft

We evaluated the relationship between patients' satisfaction and objective measurements of knee stability after reconstruction of the ACL using a patellar tendon autograft. An examination of 59 patients 2-7 years after surgery was carried out. Assessment was made by the Knee and Osteoarthritis Outcome Score for patient satisfaction, a modified International Knee Documentation Committee form for clinical knee stability and a Telos stress radiography for PA stability. The results show that patients' satisfaction was much greater than the objective evaluation would suggest. We conclude that documenting mechanical knee stability alone is inadequate for follow-up studies and a questionnaire assessing patient satisfaction should be added.

Immunochemical characterization of a chicken egg yolk antibody to secretory forms of rat incisor amelogenin

Amelogenins represent the major component of the organic matrix of enamel, and consist of several intact and degraded forms. A precise knowledge of their respective distributions throughout the enamel layer could provide some insight into their functions. To date, no antibody exists that can selectively detect the secretory forms of amelogenin. In this study we used the chicken egg yolk system to generate an antibody to recombinant mouse amelogenin. Immunoblots of whole homogenates from rat incisor enamel organs and enamel showed that the resulting antibody (M179y) recognized proteins corresponding to the five known secretory forms of rat amelogenin. Immunogold cytochemistry demonstrated that reactivity was restricted to ameloblasts and enamel. Secretory forms of amelogenin persisted in significant amounts throughout the enamel layer. The density of labeling was highest over the surface portion of the enamel layer, but enamel growth sites in this region showed a localized paucity of gold particles. Immunoreactivity was lowest over the mid-portion of the layer and increased moderately near the dentino-enamel junction. These results indicate that intact forms of amelogenin probably have a more complex distribution in the enamel layer than was heretofore suspected.

Comparative immunochemical analyses of the developmental expression and distribution of ameloblastin and amelogenin in rat incisors

Mineralized tissues are unique in using proteins to attract and organize calcium and phosphate ions into a structured mineral phase. A precise knowledge of the expression and extracellular distribution of matrix proteins is therefore very important in understanding their function. The purpose of this investigation was to obtain comparative information on the expression, intracellular and extracellular distribution, and dynamics of proteins representative of the two main classes of enamel matrix proteins. Amelogenins were visualized using an antibody and an mRNA probe prepared against the major alternatively spliced isoform in rodents, and nonamelogenins by antibodies and mRNA probes specific to one enamel protein referred to by three names: ameloblastin, amelin, and sheathlin. Qualitative and quantitative immunocytochemistry, in combination with immunoblotting and in situ hybridization, indicated a correlation between mRNA signal and sites of protein secretion for amelogenin, but not for ameloblastin, during the early presecretory and mid- to late maturation stages, during which mRNA signals were detected but no proteins appeared to be secreted. Extracellular amelogenin immunoreactivity was generally weak near secretory surfaces, increasing over a distance of about 1.25 microm to reach a level slightly above an amount expected if the protein were being deposited evenly across the enamel layer. Immunolabeling for ameloblastin showed an inverse pattern, with relatively more gold particles near secretory surfaces and much fewer deeper into the enamel layer. Administration of brefeldin A and cycloheximide to stop protein secretion revealed that the immunoblotting pattern of amelogenin was relatively stable, whereas ameloblastin broke down rapidly into lower molecular weight fragments. The distance from the cell surface at which immunolabeling for amelogenin stabilized generally corresponded to the point at which that for ameloblastin started to show a net reduction. These data suggest a correlation between the distribution of amelogenin and ameloblastin and that intact ameloblastin has a transient role in promoting/stabilizing crystal elongation. (J Histochem Cytochem 46:911-934, 1998)

The effects of acute exercise and increased atmospheric pressure on the hemostatic mechanism and plasma catecholamine levels

The hemostatic response to acute exercise and increased atmospheric pressure was studied in 20 healthy male subjects (18-35 yr of age) exercised to volitional exhaustion on a cycle ergometer in a hyperbaric chamber at 3 atmospheres absolute (ATA). As a means of comparison, 6 of the 20 subjects were exercised in the same manner at 1 ATA. Similar increases in fibrinolytic activity (FA), Factor VIII activity (VIII:C), von Willebrand factor antigen (vWF:Ag) and plasma catecholamine levels were observed following acute exercise at 1 ATA and at 3 ATA. There were no changes in the levels of plasminogen, antithrombin III, Protein C or Fibrinopeptide A (FPA) with exercise either at 1 ATA or at 3 ATA. In addition, there were no changes in plasma catecholamine levels or any of the hemostatic variables measured when atmospheric pressure was increased from 1 ATA to 3ATA without exercise. These findings demonstrate that increasing atmospheric pressure from 1 ATA to 3 ATA does not alter the exercise-induced changes in hemostasis. Therefore, exercise or physical exertion at 3 ATA for a time period not to exceed 30 min does not perturb the hemostatic mechanism and increase the risk of bleeding or thrombosis.

Prognostic value of indocyanine green and lidocaine kinetics for survival and chronic hepatic encephalopathy in cirrhotic patients following elective end-to-side portacaval shunt

The objective of this study was to assess the prognostic value of spontaneous portosystemic shunting and liver function for survival and spontaneous hepatic encephalopathy after end-to-side portacaval shunt in cirrhotic patients. One hundred ninety-eight patients with variceal hemorrhage as shown by endoscopy were evaluated. Forty-five were excluded because of uncontrollable hemorrhage; 84 were rejected because they were poor operative risk, had portal vein thrombosis or had been previously treated with beta-blockers, sclerotherapy or surgery. The remaining 69 patients were enrolled in this prospective study. There were 43 patients with alcoholic cirrhosis, 23 with cryptogenic cirrhosis and three with primary biliary cirrhosis. The severity of liver disease was assessed according to the Pugh classification: 37 patients (54%) had Pugh's score 5 to 7, 26 (38%) had 8 to 10 and six (8%) had 11 to 12. Indocyanine green intrinsic clearance was used as a probe of preoperative liver function and lidocaine systemic availability as an index of spontaneous preoperative shunting. All the patients underwent an elective end-to-side portacaval shunt. The length of minimal follow-up was 40 months. One-year survival was 76% and 5-year survival was 46%. During follow-up, 25 patients died from their liver disease and 11 patients died from various causes unrelated to their liver disease. Spontaneous chronic encephalopathy occurred in 16 patients (23%). Age, Pugh's score, active alcoholism, indocyanine green intrinsic clearance and lidocaine systemic availability were tested as prognostic factors in a multivariate analysis.(ABSTRACT TRUNCATED AT 250 WORDS)

Hemodynamic changes in portal circulation after portosystemic shunts: use of duplex sonography in 43 patients

Forty-five patients with 46 surgical portosystemic shunts were examined by duplex Doppler sonography, and the results were compared with those of esophageal endoscopy, angiography, surgery, and clinical follow-up. Thirty-eight shunts were patent, and in 33 of these, the shunt was directly visualized and flow was observed with Doppler sonography. Eight shunts were obstructed. After a successful portosystemic shunt procedure, flow in the shunted splanchnic vein was directed toward the shunt and the systemic vein. We studied the intrahepatic portal venous circulation in all of the patients; we found that in the presence of patent portosystemic shunt, portal flow is hepatofugal. This reversal of blood flow occurred in all but four patients. In the end-to-side portacaval shunt, where the portal vein is ligated, blood in intrahepatic portal branches presumably reaches the shunt through perihepatic collaterals. In the presence of a thrombosed shunt, intrahepatic portal venous flow was hepatopetal. To our knowledge, this is the first noninvasive in vivo study of intrahepatic portal circulation after portosystemic shunt surgery. The duplex Doppler evaluation of portosystemic shunts appears to be reliable and should be the method of choice for shunt patency assessment in patients with recurrent signs of portal hypertension. In addition to demonstrating flow at the site of the anastomosis, the Doppler study may yield an easy and reliable sign of shunt patency: reversed flow (hepatofugal flow) in the intrahepatic portal veins probably signals a patent shunt, even if the site of the anastomosis cannot be visualized directly by sonography.

Emergency portacaval shunt for variceal hemorrhage. A prospective study

Emergency portacaval shunt for variceal bleeding is associated with a high operative mortality, particularly if used as a last resort. Because of this, a strong case has been made against emergency shunt. This report describes an experience with emergency portacaval shunt for the treatment of variceal bleeding when used systematically after hemodynamic stabilization and control of the bleeding episode with balloon tamponade, if necessary, in patients with mild or moderate liver disease. The population studied comprised 62 consecutive patients who rebled from varices while participating in a controlled trial of propranolol for the prevention of rebleeding. Of the 62 patients, nine died of massive hemorrhage and 53 survived the hemorrhage. Of the 53 survivors, 11 had severe liver disease and were not considered for shunt surgery. Of the remaining 42 patients with mild or moderate liver disease, 36 had emergency central portacaval shunt. The interval between endoscopic diagnosis of variceal bleeding and surgery averaged 19 +/- 3 hours (mean +/- SE). The operative mortality rate, defined as in-hospital mortality, was 19%. One- and 2-year survival rates were 78% and 71%, respectively. The incidence of postoperative hepatic encephalopathy was 36%; all patients responded favorably to protein restriction and lactulose. Thus, under specific conditions, emergency portacaval shunt results in an acceptable long-term survival rate. In patients with mild or moderate liver disease, emergency portacaval shunt should be considered when other forms of treatment for the prevention of variceal rebleeding have failed.

The recanalized umbilical vein in portal hypertension: a myth

The demonstration of a vessel in the falciform ligament, traditionally presumed to be a reopened umbilical vein, is an important sonographic sign of portal hypertension. This vessel was sought in 200 umbilicoportographies (all portal hypertensive) and in 41 autopsy-dissected falciform ligaments (34 normal and seven cirrhotic). The normal falciform ligament contained one to three tiny collapsed paraumbilical veins. In cirrhotics, the number and caliber of paraumbilical veins increased. A reopened umbilical vein was never found. The authors conclude that the umbilical vein does not recanalize in portal hypertension. The vessel involved is actually an enlarged paraumbilical vein.

Portal venous system measurements in portal hypertension

The diameters of the portal, splenic, superior mesenteric, and coronary veins were measured during umbilicoportal venography in 64 cirrhotic patients with or without portal hypertension. The diameter of the portal vein did not increase along with the portohepatic gradient and even tended to decrease depending on the severity of hypertension and the opening of spontaneous portosystemic shunts. While there was no relationship between portohepatic gradient and splenic or superior mesenteric vein diameter, a coronary vein larger than 0.7 cm was associated with a portohepatic gradient greater than 10 mm Hg. This could be a useful sign of severe portal hypertension.

Symposium on portal hypertension and its complications: current management. Preoperative assessment and predictors of encephalopathy

None of the preoperative predictors of encephalopathy proposed so far to evaluate the risk of portacaval shunting in cirrhotic patients has been of value. The authors have found, in preliminary studies, that measurement of the hepatic extraction of indocyanine green (ICG), which correlates highly with the "functional" portal blood supply, could be of prognostic value: cirrhotic patients with a near-normal value for ICG extraction often have encephalopathy after portacaval shunting whereas those with a low ICG extraction value seldom have encephalopathy. These preliminary data suggest that cirrhotic patients with markedly decreased ICG extraction have a lesser risk of encephalopathy since their portal blood supply is already shunted away from hepatocytes before the operation because of anatomic changes in the liver microcirculation.

THE ROLE OF METAL-ION BINDING IN MODIFYING THE TOXIC EFFECTS OF SULPHUR DIOXIDE ON THE LICHEN UMBILICARIA MUHLENBERGII: II. 14 C-FIXATION STUDIES

Total ¹⁴ C fixation in Umbilicaria muhlenbergii was not significantly affected at levels near the capacity of the first binding site (c. 12 μmol g^-1 ) of class A metal ions or borderline metal ions with class A characteristics: i.e. Sr²⁺ , Mg²⁺ , Ca²⁺ , Ni²⁺ , and Zn²⁺ . Although both Cu²⁺ and Pb²⁺ are borderline ions with significant class B character, only Cu²⁺ greatly reduced fixation. However Ni²⁺ and Pb²⁺ , as well as Cu²⁺ , induced increased photosynthate release from lichen samples. Protection against damage due to SO₂ exposure was rendered by the uptake of class A ions and even borderline ions except those normally accumulated intracellularly (Mg²⁺ , Zn²⁺ ) or possessing the capacity to penetrate cells readily (Cu²⁺ ). Of the borderline ions tested, Pb²⁺ , Cu²⁺ and Ni²⁺ , as well as SO₂ , induced changes resulting in the incorporation of less ¹⁴ C into ribitol and more into sucrose and other sugars during photosynthesis by the lichen samples. The presence of the class A ion Ca²⁺ caused a shift in the opposite direction. The presence of Ca²⁺ , Ni²⁺ , Pb²⁺ , but not Cu²⁺ , on the lichen tended to inhibit the large SO₂ -induced shift away from ribitol production. The threshold levels of various metals reported from field studies to result in visible damage are discussed in terms of the observed photosynthetic perturbations, K²⁺ leakage and factors determining metal uptake by lichens. Finally, the ecological significance of the ability of Ca²⁺ to protect lichens against the damaging effects of air pollution is discussed.

THE ROLE OF METAL-ION BINDING IN MODIFYING THE TOXIC EFFECTS OF SULPHUR DIOXIDE ON THE LICHEN UMBILICARIA MUHLENBERGII: I. POTASSIUM EFFLUX STUDIES

K⁺ efflux from Umbilicaria muhlenbergii was not affected following the uptake of known amounts (< 20 μmol g^-1 ) of Ca²⁺ , Mg²⁺ , Sr²⁺ and Zn²⁺ , but was increased in the cases of Cu²⁺ and Pb²⁺ . In a number of samples that had taken up increasing amounts of Cu²⁺ , a discontinuity in K⁺ release during metal incubation correlated with a decrease in subsequent ¹⁴ C fixation. Some of the binding sites associated with the first phase of Cu²⁺ uptake (up to 12 μmol g^-1 ) are interpreted to occur near, on or within the algal cells. The larger K⁺ loss associated with higher Cu²⁺ uptake levels indicated that a component of the second Cu²⁺ uptake phase involved binding at or penetration of the fungal membranes. The uptake of Sr²⁺ , Ni²⁺ and Zn²⁺ conferred some protection to samples subsequently exposed to 75 p.p.m. aqueous SO₂ for 1 h, while Mg²⁺ , and Ca²⁺ had no effect. The combined effects of Cu²⁺ uptake and SO_S exposure (and also Pb²⁺ and SO₈ ) were approximately cumulative. Finally, the results are explained by reference to a classification that separates metal ions into three chemically and biologically significant categories. It is concluded that class A metal ions (those with a preference for ionic interactions) and borderline metal ions with class A character tend to protect lichens against SO₂ damage, while borderline metal ions with class B character (a preference for covalent interactions) have the opposite effect.

Idiopathic portal hypertension

Idiopathic portal hypertension is reported in five cases including one case of chronic arsenical intake and one case of chronic industrial vinyl chloride exposure. In all five cases the patients presented with gastrointestinal bleeding as the chief complaint. Physical examination was within normal limits except for splenomegaly in all. Results of liver function tests were normal, except for the relative clearance of sulfobromophtalein. A surgical liver biopsy specimen was obtained in all cases and showed moderate degrees of portal fibrosis, but no cirrhosis. Combined umbilicoportal, hepatic vein and superior mesenteric artery catheterization was performed in all cases. Hepatoportographies showed distortion of the intrahepatic portal venous system and cut-off of small portal venules. Porto-hepatic gradients ranged from 14.0 to 20.5 mm Hg. The portal hypertension was both sinusoidal and presinusoidal in nature but mainly presinusoidal. Hepatic extraction of indocyanine green and of albumin microaggregates was normal, thereby suggesting normal functional portal blood supply to the liver. The patients with arsenical or vinyl chloride exposure could not be differentiated from the other three patients with idiopathic portal hypertension. These results suggest that idiopathic portal hypertension may be related to domestic or industrial exposure to other hepatotoxins.

Cation-exchange equilibrium and mass balance in the lichen Umbilicaria muhlenbergii

Equilibrium studies on the thallus of U. muhlenbergii (Ach.) Tuck. confirmed that the mass balance of the exchange of Ni2+ for Sr2+, Sr2+ for Tl+, and Sr2+ for H+ was consistent with a cation-exchange mechanism of metal-ion uptake.

Extraction of 125I-albumin microaggregates from portal blood. An index of functional portal blood supply in cirrhotics

Portal and hepatic indicator dilution curves (IDC) were obtained after injection of a mixture of 51Cr-labeled red blood cells ([51Cr]RBC) and 125I-albumin microaggregates (125I-AMA) into the cranial mesenteric artery in dogs. The extraction (E) of 125I-AMA from portal blood was measured during one passage through the hepatic reticuloendothelial system. Using [51Cr]RBC as a vascular reference substance, E-125I-AMA was calculated by comparing simultaneous [51Cr]RBC and 125I-AMA portal and hepatic IDC, and was expressed as percentage of 125I-AMA flowing through the portal vein. In 44 experiments (15 dogs), the colloid was almost completely extracted (E-125I-AMA = 92.3 +/- 1.0% (mean +/- SE)). This approach was applied in 15 patients with severe portal hypertension undergoing combined umbilicoportal, hepatic vein, and superior mesenteric artery catheterization. Eleven patients had alcoholic cirrhosis (AC) and 4 patients had idiopathic noncirrhotic portal hypertension (IPH). Using [51Cr]RBC-IDC, the portal fraction of hepatic blood flow varied between 34.1 and 100% (mean 62.6%) in AC patients and between 56.5 and 91.2% (mean 74.2%) in IPH patients. E-125I-AMA varied from 5.2 to 100% (mean 45.1%) in AC patients, although normal values were obtained in IPH patients (mean 93.2%). In all patients the extraction of Indocyanine green (E-ICG) was calculated using a continuous infusion for the estimation of hepatic blood flow. E-ICG was decreased in AC patients (mean 22.1%), although normal values were obtained in IPH patients (mean 49.5%). A highly significant correlation was found between E-125I-AMA and E-IGC (r = 0.977, P less than 0.001). Also, a significant correlation was found in all patients between E-125I-AMA and the relative clearance of ICG (r = 0.906, P less than 0.001). The correlations between the extraction or clearance of substances removed by two different cell population suggest that their decreases are mainly due to changes in liver microcirculation. In cirrhotics, the decreased E-125I-AMA can be related to part of portal blood bypassing Kupffer cells (intrahepatic portohepatic shunts) and/or to sinusoidal changes responsible for ineffective phagocytosis. Thus, E-125I-AMA can be used as an estimation of the functional portal blood supply to the liver in cirrhotics. Using portal and hepatic IDC after injection of [51Cr]RBC and 125I-AMA into the superior mesenteric artery, the portal fraction of hepatic blood flow and the functional portal blood supply can be estimated simultaneously in patients with portal hypertension before portacaval shunts.

Hemodynamic evaluation of patients with intrahepatic portal hypertension. Relationship between bleeding varices and the portohepatic gradient

Between January 1970 and December 1974, 389 patients presenting an upper gastrointestinal hemorrhage had an emergency fiberoptic esophagogastroscopy at the time of bleeding. In 103 cases, esophageal and/or gastric varices were visualized and in 46 of these cases, bleeding originiated from varices. Hemodynamic data was available in 19 cases of intrahepatic portal hypertension who had bled from varices. Combined hepatic and umbilicoportal catherterization was perform in 17 cases whereas only hepatic vein catherterization was possible in 2. The portohepatic gradient (FPVP-FHVP or WHVP-FHVP) was utilized as an index of portal hypertension. In the 19 patients studied, the portohepatic gradient ranged from 12 to 24.5 mm Hg with a mean of 18.4 mm Hg; only one patient had a portohepatic gradient of less than 14.5 mm Hg. The present data strongly suggest that in intrahepatic portal hypertension, bleeding varices are observed only if significant portal hypertension exists. Hemodynamic studies may thus be helpful in evaluating bleeding patients with varices particularly when the origin of the bleeding cannot be determined at endoscopy. The finding of a portohepatic gradient of less than 12 mm Hg would strongly suggest that varices were not the source of bleeding and in these cases, shunt surgery should not be considered.

Portal and systemic effects of selective infusion of vasopressin into the superior mesenteric artery in cirrhotic patients

Selective infusion of vasopressin (0.2 U per min) was performed in 8 cirrhotic patients with portal hypertension who underwent umbilicoportal catheterization. There was a significantly decreased (9.6%) of the free portal venous pressure from 27.0 plus or minus 1.4 mm Hg to 24.4 plus or minus 1.4 mm Hg. In all patients, the portal PO2 significantly decreased with a mean fall of 18.8%. However, in all patients, significant systemic effects were noted: an increase in arterial blood pressure and a decrease in the arterial PO2. In 3 patients, a marked fall of the cardiac output (greater than 2.0 liters per min) was recorded during the selective infusion of vasopressin. It is concluded that if selective infusion of vasopressin into the superior mesenteric artery is efficacious in the control of bleeding varices, the therapeutic effect cannot be totally explained by the lowering of the portal venous pressure in cirrhotic patients with portal hypertension. The risk of vascular thrombosis, the decreased portal PO2, and the systemic effects have to be considered when this approach is used in cirrhotic patients with ruptured esophageal and/or gastric varices.

Noncirrhotic presinusoidal portal hypertension associated with chronic arsenical intoxication

A 39-year-old male with bleeding esophageal varices due to portal hypertension was observed. The patient had taken an arsenical preparation during a period of 12 yr because of psoriasis and subsequently developed keratotic changes of the palms and soles of his feet and an epithelioma of the scrotum. Physical examination was unremarkable except for splenomegaly and skin lesions. Liver function tests were normal; a needle biopsy of the liver (right lobe) showed nonspecific changes. Combined hepatic and umbilicoportal catheterization revealed, on splenography and portography, huge esophageal varices and patent portal vein; dilation, distortion, and cut-off of many intrahepatic portal branches were found. A marked gradient existed between the free portal venous pressure (25 mm Hg) and the wedged hepatic venous pressure (9.5 mm Hg). Hepatic blood flow, portal PO2, cardiac output, cardiac index, and blOOD volume were within normal range. Arteriographies did not reveal arteriovenous shunts in the splanchnic or splenic vessels. A splenorenal shunt were performed and a wedged biopsy of the liver (left lobe) revealed nonspecific changes. Three years later the patient had not experienced any episode of hemorrhage or hepatic encephalopathy but developed an epithelioma of the tongue. No known cause could be incriminated in the pathogenesis of the portal hypertension. However, there was unequivocal chronic arsenic intoxication. Toxic hepatitis, cirrhosis, noncirrhotic portal hypertension, and hemangiosarcoma of the liver have been reported with the intake of arsenicals. Thus, it is suggested that in this patient, presinusoidal portal hypertension was secondary to chronic arsenical intake associated with marked intrahepatic vascular changes seen on portography.

Combined hepatic vein, umbilicoportal vein, and superior mesenteric artery catheterization in portal hypertension: estimation of the portal fraction of total hepatic blood flow in cirrhotic patients

Hemodynamic data were obtained in 13 cirrhotic patients with severe portal hypertension, undergoing combined hepatic vein, umbilicoportal vein, and superior mesenteric artery catheterization. The relative clearance of indocyanine green, the portohepatic gradient (difference between the free portal venous pressure and the free hepatic venous pressure), and the estimated hepatic blood flow were measured. The portal fraction (PF) of total hepatic blood flow was calculated in all patients using indicator dilution curves obtained from the portal bifurcation, a right hepatic vein, and when possible a left hepatic vein (six cases) after injection of (51)Cr-labeled red blood cells ((51)Cr RBC) into the superior mesenteric artery. Flows were overestimated because of loss of indicator through spontaneous portosystemic shunts; however, the ratio between hepatic and portal indicator dilution curves can be used to calculate the portal fraction of total hepatic blood flow since no extrahepatic shunts existed after the bifurcation of the portal vein (as shown on portography). In 10 patients, 15 series of curves were calculable and the PF varied between 30.1 and 100% (mean ± SE: 71.1 ± 6.2%). In the three other patients, only delayed activity from recirculation was detected from portal and hepatic vein samples and PF was 0%; in these three cases, portography and arteriography revealed spontaneous portacaval shunting with reverse and/or stagnant circulation in the portal vein. In the 13 patients, no correlation existed between PF and the relative clearance of indocyanine green or the portohepatic gradient, parameters generally used as indices of severity in cirrhosis. In 10 patients, no correlation was found between PF and the estimated hepatic blood flow.These data indicate that (51)Cr RBC dilution curves can be used for the estimation of the portal fraction of total hepatic blood flow in conscious cirrhotic patients before portacaval shunts. Using this methodology, it could be assessed whether any critical level of portal fraction exists above which poor clinical results occur after portacaval shunting. This measurement could eventually be helpful in determining the appropriate surgical procedure to be applied in individual cases.