Study on cellulose nanofibrils/copolymacrolactone based nano-composites with hydrophobic behaviour, self-healing ability and antioxidant activity

The multiple uses of cellulose nanofibrils (CNFs) originate from their availability from renewable resources, and are due to their physico-chemical properties, biodegradability and biocompatibility. At the same time, reducing sensitivity to humidity, increasing interfacial adhesion and hydrophobic modification of the CNF surface to diversify applications and improve operation, are current targets pursued. This study focuses on the preparation of a novel gel structure using cellulose nanofibrils (CNFs) and poly(ethylene brassylate-co-squaric acid) (PEBSA50/50), a bio-based copolymacrolactone. The primary goal is to achieve the gel with reduced sensitivity to humidity and enhanced hydrophobic behaviour. The new system was characterized in comparison to its constituent components using various techniques, such as Fourier transform infrared spectroscopy, thermal analysis, X-ray diffraction, and NIR - chemical imaging. Rheological tests demonstrated the formation of the CNF_PEBSA50/50 gel as a result of physical interactions between the two polymeric partners and revealed self-healing abilities for the prepared gels. Determination of the contact angle, surface free energy, as well as dynamic measurements of the vapour sorption of the CNF_PEBSA50/50 system, confirmed the achievement of the study's aim. Furthermore, the CNF_PEBSA50/50 network was utilized to encapsulate citric acid, resulting in the creation of a new bioactive composite with both antioxidant and antimicrobial activity.

Evaluation and implications of mitral regurgitation using cMRI in patients with hypertrophic cardiomyopathy

OBJECTIVE

Mitral regurgitation (MR) represents an important feature in patients with hypertrophic cardiomyopathy (HCM) due to left ventricular outflow tract (LVOT) obstruction and mitral valve systolic anterior motion (SAM). Mitral valve anatomical variants associated with HCM also contribute to the severity of MR. The aim of this study is to evaluate MR severity and its correlation with different parameters in patients with HCM using cardiac magnetic resonance imaging (cMRI).

PATIENTS AND METHODS

130 patients with HCM underwent cMRI. Parameters assessed for the quantification of MR severity were mitral regurgitation volume (MRV) and mitral regurgitation fraction (MRF). cMRI was also used to characterize LV function, left atrium volume (LAV) index, filling pressures and structural abnormalities associated with HCM, all in correlation to MR.

RESULTS

Patients with HCM had mild (26.9%), moderate (52.3%) or severe (20.7%) MR. Most relevant parameters related to MR severity were MRV and MRF; other parameters with strong correlation with MR were LAV index and E/E' ratio, both increasing with its severity. Patients with LVOT obstruction had more severe MR (70.3%), 79% of them due to SAM. LV ejection fraction (LVEF) increased proportionally with the severity of MR, while LV strain (LAS) was inversely correlated with it. Independent predictors for quantifying the severity of MR, after the adjustment for covariates, were MRV, MRF, SAM, LAV index and E/E'.

CONCLUSIONS

cMRI can accurately assess MR in patients with HCM, especially by using novel indicators, MRV and MRF respectively, along with LAV index and E/E' ratio. Severe MR, due to SAM, is more frequent in the obstructive form of HCM (HOCM). Also, the severity of MR is significantly associated with significantly associated with MRV, MRF, LAV index and E/E' ratio.

Automatic Detection of the Orientation of Strain Gauges Bonded on Composite Materials with Polymer Matrix, in Order to Reduce the Measurement Errors

Composite materials with a polymer matrix are used on a large scale to make light structures that involve high responsibility. The failure mechanisms of composite materials are very complex and for this reason, advanced techniques for damage detection and the assessment of structural integrity are required. The continuous structural health monitoring (SHM) uses nondestructive testing (NDT) techniques, sensors integrated into the structures, computers and dedicated software. This article presents a new automatic and precise method for detecting the orientation of strain gauges glued onto composite materials with a polymer matrix. The automatic identification of both the directions of the reinforcing fibers and that of the orientation of the strain gauge, respectively, allows for the calculation of the angle between these two directions. By knowing the difference between the nominal value of this angle and the value actually obtained after gluing the strain gauge, corrections obtained by calculation on the experimental values can be applied, using equations found in specialized literature. In this way, a drastic reduction of measurement errors introduced by the misalignment of strain gauges glued on composite materials can be achieved, resulting in a significant increase of measurement accuracy, which contributes to increasing the security of the monitored structures.

Analytical modelling of food storage cooling with solar ammonia-water absorption system, powered by parabolic trough collectors. Method

The study presents a new analytical model capable to reveal the thermal behaviour of all the components of the solar ammonia-water absorption system, powered by parabolic trough collectors, serving different types of food storages: refrigeration chamber, refrigerated food storage, freezing chamber and frozen food storage. The heat inputs, that determine the total cooling load, for each food storage spaces consist of: heat gains through walls, heat gains through ventilation (fresh air), heat that must be dissipated from the stored products (technological cooling load required to cool down the products) and heat gains through operation. The influence of the number of solar parabolic trough collectors and of the storage tank size on different parameters of the refrigeration plant are investigated under low and high storage temperatures.•Food cooling with solar absorption refrigeration system.•Hourly based variation of NH₃-H₂O solar absorption system performances.•Long term simulation of solar absorption cooling for refrigeration and cooling.

Left ventricular longitudinal contraction impacts the left atrial appendage function and the occurrence of thromboembolic events in patients with atrial fibrillation

Introduction

Previous research has revealed a relationship between left ventricular (LV) function and incidence of stroke in atrial fibrillation (AF) but the mechanism remains unknown.

Purpose

Given that the left atrial appendage (LAA) is located in the vicinity of the LV base we hypothesized that the LV longitudinal contraction has an impact on the LAA function, LAA thrombus (LAAT) formation, and occurrence of ischemic stroke (Figure 1A). The aim of this study was to investigate this phenomenon using transesophageal echocardiography (TEE).

Material and methods

We included in our study 105 consecutive patients (age 59±11; 55 men) undergoing TEE-guided cardioversion for AF. LV longitudinal function was assessed using the mitral annulus plane systolic excursion (MAPSE). LAA function was evaluated using the LAA emptying velocity (LAAEV) and LAA ejection fraction (LAAEF) (Figure 1B). The presence LAAT and spontaneous echo contrast (SEC) were evaluated as well.

Results

Our patients had a median CHADS2vasc score = 3 (IQR 2–4), LVEF=50±11%, and MAPSE=7.3±1.7mm. MAPSE showed a positive significant correlation with both LAAEV (r=0.34; p<0.01) and LAAEF (r=0.23; p<0.05) (Figure 2). LVEF correlated significantly with LAAEV (r=0.42, p<0.01), and LAA area (r=−0.34; p<0.05), respectively. Additionally, patients who exhibited SEC had significantly lower LAAEF as well as LAAEV when compared with patients without SEC: 31±12% vs 38±12% P=0.022 and 35±18cm/s vs 49±21cm/s P=0.005. Patients who displayed both SEC and LAAT had wider LAA neck when compared to the rest of the group (21.46±3.96mm vs. 18.23±3.78mm; P=0.021). Logistic regression analysis revealed that MAPSE independently predicted the occurrence of ischemic stroke both in univariate and multivariate models that also included the CHADSvasc2 score.

Conclusions

LV longitudinal contraction appears to influence LAA function. This relationship could potentially have an impact on occurrence of thromboembolic events in patients with atrial fibrillation.

Funding Acknowledgement

Type of funding sources: None.

A state of the art review of isochoric cryopreservation and cryoprotectants

There is a developing enthusiasm for discovering new methods, cryoprotectants, systems and devices for cells, tissues, and organ preservation in medicine, in sub-zero temperature conditions and a growing interest in developing more efficient and economical methods for long-term preservation of food in a frozen state. Most of the preservation protocols currently used in medicine and food preservation involve the use of atmospheric pressure, and temperatures lower than normal body temperature in medicine, or lower than room temperature in the food industry. In this state of the art review, we analyzed the results of a new preservation method that uses an isochoric system. We aimed to offer a clear overview of the potential of this new technology. Firstly, to study the origins of isochoric preservation, we searched using the WoS Database. A search with the world "isochoric" returned 488 results. A more specific search of the term isochoric freezing returned 94 results. From these searches, we selected the 12 most relevant articles and discuss them here in detail. We present an overall characterization and criticism of the current use and potential of this new preservation method that can be used in the medicine and food industry. The main findings indicate encouraging results for the tested biological matter, including for the preservation of food products (e.g. cherries, spinach, potatoes), biological organisms (e.g. Caenorhabditis elegans, Escherichia coli, Listeria, Salmonella typhimurium), organs (e.g. rat hearts), tissues (e.g., tilapia fish filets) or cells (e.g., mammalian cells, pancreatic cells). Accordingly, we conclude that the isochoric system holds huge potential as a new technique in the field of preservation. doi.org/10.54680/fr22410110112.

The Use of Organic Rankine Cycles for Recovering the Heat Lost in the Compression Area of a Cryogenic Air Separation Unit

The use of organic Rankine cycles (ORCs) is a viable solution for the recovery of waste heat. For an air separation unit (ASU) with a production of V˙O2=58300mN3/h operating in Romania, the value of utilization of the heat transferred to the cooling system of the compression area represents 21% of the global system electrical energy input. To recover this thermal energy and transform it into mechanical energy, an ORC system was proposed. To maximize the production of mechanical power, an exergy analysis was performed. Exergy analysis was used to choose the most suitable organic fluid and find the optimum constructive structure of the Rankine cycle. The calculation of the exergy destruction in the key apparatuses of the system allowed investigation into the optimization search procedure. The large exergy destruction in the liquid preheater suggested the decrease in the temperature difference in this part of the evaporator by increasing the inlet temperature of the liquid; and an internal recuperative heat exchanger was used for this purpose. When permitted, the overheating of the vapors also reduced the temperature difference between the heat source and the organic fluid during the heat transfer process. The analysis was comparatively performed for several organic fluids such as R-245fa, R123, n-pentane and R717. The use of ammonia, that offered the possibility of superheating the vapors at the turbine inlet, brought a gain of mechanical power corresponding to 6% economy in the electrical energy input of the global plant.

Policy framework for building integrated care for TB patients in Romania: setting up the scene

Problem

Romania put many efforts for TB control, but despite a constant decreasing trend since almost two decades, TB remained a public health concern, due to the notification rate (highest in EU), the number of resistant cases and the mortality. A national strategy for TB control has been issues for 2015-2020, but its implementation was fragmentary.

Description of the Problem

Benefiting for a series of programs financed by the Global Fund to Fight AIDS, Tuberculosis and Malaria, Romania performed a detailed analysis of the national context, on four pillars (governance and accountability, service delivery, organizational capacity, resources). Quantitative data collected through routine systems were combined to interviews with key informers and focus groups with medical staff, patients and NGOs active in supporting key vulnerable population.

Results

A national framework for strengthening the implementation of the strategy was set up under a Tailored to Transition Global Fund Grant. This framework put together the policy and the technical levels and the civil society sector. Main interventions aimed to strengthen the governance, to improve the procurement and supply mechanism, to develop the ambulatory patient-centered model of care and to create tools for improving the access of key vulnerable population to basic integrated medical and social services.

Lessons

Translating the good practice models developed by the NGO sector to permanent (governmental) structures was difficult due to more rigorous legislative framework for public systems.

Key messages

Multisectoral approach is essential for building integrated care for TB patients. Integration of services should focus not only to complex medical needs, but also to the social ones.

Shape transitions between and within Zr isotopes

The Zirconium isotopes across the N=56,58 neutron sub­shell closures have been of special interest since years, sparked by the near doubly-magic features of 96Zr and the subsequent rapid onset of collectivity with a deformed ground-state structure already in 100Zr. Recent state-of-the-art shell model approaches did not only correctly describe this shape-phase transition in the Zr isotopic chain, but alsothe coexistence of non-collective structures and pronounced collectivity especially in 96,98Zr. Theisotope 98Zr is located on the transition from spherical to deformed ground state structures. We summarize recent experimental work to obtain the B(E2) excitation strengths of the first 2+ state of98Zr, including a new experiment employing the recoil-distance Doppler-shift method following a two-neutron transfer reaction.

A comparison of freezing-damage during isochoric and isobaric freezing of the potato

Background

Freezing is commonly used for food preservation. It is usually done under constant atmospheric pressure (isobaric). While extending the life of the produce, isobaric freezing has detrimental effects. It causes loss of food weight and changes in food quality. Using thermodynamic analysis, we have developed a theoretical model of the process of freezing in a constant volume system (isochoric). The mathematical model suggests that the detrimental effects associated with isobaric freezing may be reduced in an isochoric freezing system. To explore this hypothesis, we performed a preliminary study on the isochoric freezing of a produce with which our group has experience, the potato.

Method

Experiments were performed in an isochoric freezing device we designed. The device is robust and has no moving parts. For comparison, we used a geometrically identical isobaric freezing device. Following freezing and thawing, the samples were weighed, examined with colorimetry, and examined with microscopy.

Results

It was found that potatoes frozen to −5 °C in an isochoric system experienced no weight loss and limited enzymatic browning. In contrast the −5 °C isobaric frozen potato experienced substantial weight loss and substantial enzymatic browning. Microscopic analysis shows that the structural integrity of the potato is maintained after freezing in the isochoric system and impaired after freezing in the isobaric system.

Discussion

Tissue damage during isobaric freezing is caused by the increase in extracellular osmolality and the mechanical damage by ice crystals. Our thermodynamic analysis predicts that during isochoric freezing the intracellular osmolality remains comparable to the extracellular osmolality and that isochoric systems can be designed to eliminate the mechanical damage by ice. The results of this preliminary study seem to confirm the theoretical predictions.

Conclusion

This is a preliminary exploratory study on isochoric freezing of food. We have shown that the quality of a food product preserved by isochoric freezing is better than the quality of food preserved to the same temperature in isobaric conditions. Obviously, more extensive research remains to be done to extend this study to lower freezing temperatures and other food items.

Effects of supplementation with pomegranate juice on plasma C-reactive protein concentrations: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Pomegranate juice (PJ) has a high content of antioxidants and bioactive polyphenols, being widely used for its antioxidant, anti-inflammatory and chemopreventive effects.

PURPOSE

The objective of this meta-analysis consisted in investigating the impact of PJ on plasma C-reactive protein (CRP) concentrations.

METHODS

The search included SCOPUS, Medline and two Iranian bibliographic databases namely MagIran and Scientific Information Database (from inception to December 09, 2014) to identify prospective trials for investigating the impact of pomegranate preparations on serum concentrations of CRP. Two independent reviewers extracted data on study characteristics, methods and outcomes.

RESULTS

Among 427 participants in the selected studies, 216 were allocated to PJ groups, and 211 to control group. Meta-analysis of data from 5 eligible randomized controlled trials (RCTs) arms did not provide compelling evidence as to a significant CRP-lowering effect of supplementation with pomegranate juice (WMD: -0.22 mg/l, 95% CI: -0.45, 0.01, p = 0.061). The impact of pomegranate juice on plasma CRP levels was found to be independent of duration of supplementation (slope: 0.003; 95% CI: -0.005, 0.011; p = 0.444).

CONCLUSION

In conclusion, this meta-analysis of data from 5 prospective trials did not indicate a significant effect of PJ on plasma CRP levels, and this effect was independent of duration of supplementation.

User Interface Design in Medical Distributed Web Applications

User interfaces are important to facilitate easy learning and operating with an IT application especially in the medical world. An easy to use interface has to be simple and to customize the user needs and mode of operation. The technology in the background is an important tool to accomplish this. The present work aims to creating a web interface using specific technology (HTML table design combined with CSS3) to provide an optimized responsive interface for a complex web application. In the first phase, the current icMED web medical application layout is analyzed, and its structure is designed using specific tools, on source files. In the second phase, a new graphic adaptable interface to different mobile terminals is proposed, (using HTML table design (TD) and CSS3 method) that uses no source files, just lines of code for layout design, improving the interaction in terms of speed and simplicity. For a complex medical software application a new prototype layout was designed and developed using HTML tables. The method uses a CSS code with only CSS classes applied to one or multiple HTML table elements, instead of CSS styles that can be applied to just one DIV tag at once. The technique has the advantage of a simplified CSS code, and a better adaptability to different media resolutions compared to DIV-CSS style method. The presented work is a proof that adaptive web interfaces can be developed just using and combining different types of design methods and technologies, using HTML table design, resulting in a simpler to learn and use interface, suitable for healthcare services.

Stacking fault related luminescence in GaN nanorods

Optical and structural properties are presented for GaN nanorods (NRs) grown in the [0001] direction on Si(111) substrates by direct-current reactive magnetron sputter epitaxy. Transmission electron microscopy (TEM) reveals clusters of dense stacking faults (SFs) regularly distributed along the c-axis. A strong emission line at ∼3.42 eV associated with the basal-plane SFs has been observed in luminescence spectra. The optical signature of SFs is stable up to room temperatures with the activation energy of ∼20 meV. Temperature-dependent time-resolved photoluminescence properties suggest that the recombination mechanism of the 3.42 eV emission can be understood in terms of multiple quantum wells self-organized along the growth axis of NRs.

User experience integrated life-style cloud-based medical application

Having a modern application capable to automatically collect and process data from users, based on information and lifestyle answers is one of current challenges for researchers and medical science. The purpose of the current study is to integrate user experience design (UXD) in a cloud-based medical application to improve patient safety, quality of care and organizational efficiency. The process consists of collecting traditional and new data from patients and users using online questionnaires. A questionnaire dynamically asks questions about the user's current diet and lifestyle. After the user will introduce the data, the application will formulate a presumptive nutritional plan and will suggest different medical recommendations regarding a healthy lifestyle, and calculates a risk factor for diseases. This software application, by design and usability will be an efficient tool dedicated for fitness, nutrition and health professionals.

eduCRATE--a Virtual Hospital architecture

eduCRATE is a complex project proposal which aims to develop a virtual learning environment offering interactive digital content through original and integrated solutions using cloud computing, complex multimedia systems in virtual space and personalized design with avatars. Compared to existing similar products the project brings the novelty of using languages for medical guides in order to ensure a maximum of flexibility. The Virtual Hospital simulations will create interactive clinical scenarios for which students will find solutions for positive diagnosis and therapeutic management. The solution based on cloud computing and immersive multimedia is an attractive option in education because is economical and it matches the current working style of the young generation to whom it addresses.

Data and knowledge in medical distributed applications

Building a clinical decision support system (CDSS) capable to collect process and diagnose data from the patients automatically, based on information, symptoms and investigations is one of the current challenges for researchers and medical science. The purpose of the current study is to design a cloud-based CDSS to improve patient safety, quality of care and organizational efficiency. It presents the design of a cloud-based application system using a medical based approach, which covers different diseases to diagnosis, differentiated on most important pathologies. Using online questionnaires, traditional and new data will be collected from patients. After data input, the application will formulate a presumptive diagnosis and will direct patients to the correspondent department. A questionnaire will dynamically ask questions about the interface, and functionality improvements. Based on the answers, the functionality of the system and the user interface will be improved considering the real needs expressed by the end-users. The cloud-based CDSS, as a useful tool for patients, physicians and healthcare providers involves the computer support in the diagnosis of different pathologies and an accurate automatic differential diagnostic system.

User friendly IT Services for Monitoring and Prevention during Pregnancy

A healthy lifestyle for a mother and monitoring both mother and fetus activities are crucial factors for a normal pregnancy without hazardous conditions. This paper proposes a cloud computing solution and a mobile application which collect data from the sensors to be used in Obstetrics-Gynecology Department. This application monitors the dietary plan of the pregnant and gives her the possibility to socialize and share pregnancy experience with the rest of women from the social network from the hospital. The physicians can access the information's of the patient in real time and they can alert mothers in some situations. Using this cloud computing device, the health condition of the pregnant women may be improved.

Case report of fetal lingual tumor - perinatal care and neonatal surgical intervention

Fetal tumors are rare and can be difficult to diagnose in utero. In this presentation, we report an infantile hemangiopericytoma of the tongue, and also review the clinical characteristics, imaging appearances, perinatal differential diagnosis, and potential treatments of this tumors. Prenatal diagnosis of lingual fetal tumors with two-dimensional (2D) ultrasound presents a challenge to sonographers and perinatologists because these lesions are rare, usually develop in the third trimester of pregnancy and need a multidisciplinary approach. We describe an lingual tumor and moderate polyhydramnios which were prenatally detected at 31 weeks of gestation with two- dimensional ultrasound. The application of the surface mode of three-dimensional ultrasound improved the visualization of this tumor. Fetal Magnetic resonance imaging was performed to help in prenatal differential diagnostic. The option of prenatal cytology gained by amniocentesis should also be considered. To our knowledge there are no prenatal reports of similar cases. However, in our experience every information provided during the pregnancy, a correct and early diagnose of fetal condition helps to cope with the demands of perinatal management and to explain to the parents and neonatologists the findings of the case.

A novel pathophysiological-based panel of biomarkers for the diagnosis of nonalcoholic steatohepatitis

Non-invasive biochemical markers are useful to distinguish between nonalcoholic steatohepatitis (NASH) and simple steatosis. The aim of this study was to test the diagnostic value of a panel of biomarkers derived from the pathophysiological events involved in the development of NASH. A total of 79 patients: 20 not-NASH and 59 NASH were included in the study. Definitive NASH was defined according to Kleiner's classification. In all subjects, parameters of the metabolic syndrome, insulin resistance (HOMA-IR), adiponectin, interleukin-6 (IL-6) and total cytokeratin-18 (M65 antigen) were determined. Univariate and multivariate analysis were used to identify independent predictors of NASH. In multivariate analysis three markers were independently predictors of NASH: adiponectin, IL-6 and M65 levels. In decreasing order, the independent predictors of NASH (NAS≥5) were M65 with an AUROC of 0.791, IL-6 with an AUROC of 0.727 and adiponectin with an AUROC of 0.709. The combination of two biomarkers yelded an AUROC of 0.828 for M65 and IL-6, 0.841 for adiponectin and M65 and 0.852 for adiponectin and IL-6. The best value was obtained by triple combination: adiponectin, M65 and IL-6 with and AUROC of 0.903, Sp=85.7% (PPV=94.2%) and Se=84.5% (NPV=66.7%). In conclusion, a novel pathophysiological - based panel of biomarkers combining total CK-18, IL-6 and adiponectin may be useful to predict NASH.

Mixed hepatoblastoma in child. Case report

Hepatoblastoma represents the child's most frequent malignant hepatic tumor. We present the case of a one-year old prematurely born patient with an abdominal mass. Ultrasound and CT scan demonstrated a solid hepatic tumor. Serum alpha fetoprotein level was increased. He presented thrombocytosis and a left lobe hepatectomy was performed. Pathological examination revealed complete excision of a mixed hepatoblastoma. Hepatic tumor at a child under 3 years old correlated with elevated serum alpha fetoprotein and thrombocytosis are almost patognomonic for hepatoblastoma. Complete surgery is the mainstay of therapy in hepatoblastoma.

[Intestinal stromal tumor with large unique hepatic metastasis--diagnostic difficulties]

The digestive tract mesenchymal neoplasms were viewed modified radically once it was discovered that gastrointestinal stromal tumors (GIST), the most frequent non-epithelial digestive tumors, constitute a distinctive group of tumors originating in the interstitial cells of Cajal, cells which normally express the CD117 antigen. The discovery of GIST's origin and understanding of the molecular mechanisms underlying the development of such tumors have led to important progress concerning their diagnosis and treatment. Thus, tumoral expression of c-KIT (CD117) is presently considered to be the most specific criterion for the diagnosis of GIST, and targeted molecular therapy using thyrosin-kinase inhibitors (imatinib) has encouraging results even in the case of locally advanced or metastatic tumors. This is the case of a 47 year old man who accused nonspecific abdominal symptomatology due to a large epigastric tumor which, postoperatively, proved to be the metastasis of a stromal enteral tumor.

Alkaline reflux esophagitis in patients with total gastrectomy and Roux en Y esojejunostomy

BACKGROUND AND AIMS

Alkaline reflux esophagitis is a complication that might develop in patients with total gastrectomy. The aim of the study was to analyze the prevalence and severity of reflux esophagitis and the occurence of complications (Barrett's esophagus and esophageal stenosis) in patients with total gastrectomy and Roux en Y esojejunostomy.

METHODS

92 patients with total gastrectomy performed for gastric cancer were included in the study. None of the patients had esophagitis prior to gastrectomy. The patients were assessed clinically and endoscopically after a certain interval from surgery.

RESULTS

An important number of patients (14 out of 92, 15.22%) had reflux esophagitis; 5.43% of the patients had also complications of reflux esophagitis (Barrett's esophagus and benign esophageal stenosis) and 6.52% had local tumor recurrence. Of the 14 patients with reflux esophagitis, the majority (9/14) had Los Angeles (LA) grade C esophagitis. The mean interval between surgery and the endoscopic evaluation was 4.43 years. Barrett's esophagus and benign stenosis were diagnosed after a longer period of time (10.33 and 8 years, respectively) as compared to reflux esophagitis (5.29 years). More than half of the esophagitis patients had reflux symptoms.

CONCLUSIONS

Although Roux en Y esojejunostomy is a reconstructive technique which prevents the reflux, an important percentage of our patients developed alkaline reflux esophagitis. In most cases, the esophagitis was moderate or severe. Complications of alkaline reflux, i.e. benign stenosis and Barrett's esophagus, also occurred after longer periods of time (8 to 10 years) in a small percentage of patients.

Rapid recovery of a rectovaginal fistula with infliximab in a patient with Crohn's disease

We present the case of a female patient diagnosed with colonic Crohn's disease, having a clinical evolution with many recurrences and in whom conventional therapy had failed. The patient was admitted in our department 4 years after the onset of the disease, with an altered general state, diarrhea, malnutrition, fever and fecaloid vaginal discharge. Investigations classified the patient in a severe activity flare of Crohn's disease (CDAI 329), complicated with a rectovaginal fistula. Infliximab therapy was initiated. The evolution was rapidly favorable and the fistula closed after 4 weeks of therapy.

Performance of unidimensional transient elastography in staging non-alcoholic steatohepatitis

BACKGROUND/AIMS

Transient elastography (TE) is a noninvasive method for predicting liver fibrosis, mainly validated in patients with viral hepatitis. Information is still limited concerning its performance in non-alcoholic steatohepatitis (NASH) patients. We aimed to assess the value of TE in the prediction of fibrosis stage in NASH as well as the factors determining the discordance between the TE-predicted and the biopsy-proven fibrosis stage in these patients.

METHODS

Liver biopsy and TE were performed on 72 consecutive NASH patients. Fibrosis, lobular inflammation, ballooning and steatosis were evaluated (Brunt system).

RESULTS

Liver stiffness (LS) values ranged from 2.80 to 16.90 kPa. In the univariate analysis, LS was correlated with fibrosis (r=0.661; p<0.0001), steatosis (r=0.435, p<0.0001), ballooning (r=0.385; p=0.001) and lobular inflammation (r=0.364; p=0.002). In multivariate analysis, only fibrosis significantly correlated with LS (p<0.0001). The median (and range) LS values (kPa) according to the fibrosis stages were: 4.90 (2.80-7.30) for F0; 6.15 (4.80-12.50) for F1; 6.90 (3.30-16.90) for F2 and 14.00 (10.70-14.10) for F3, with significant difference between stages, except for F1-F2 (p=0.249). Cut off values were calculated for predicting each fibrosis stage: 5.3 kPa (AUROC=0.879) for F1; 6.8 kPa (AUROC=0.789) for F2; and 10.4 kPa (AUROC=0.978) for F3. Patients with false-positive results had a significantly higher ALT level than those with concordant results (p=0.039).

CONCLUSION

In NASH patients, TE allows a reliable assessment and prediction of liver fibrosis, especially in advanced stages. Steatosis, ballooning and inflammation do not influence liver stiffness.

Performance of a new elastographic method (ARFI technology) compared to unidimensional transient elastography in the noninvasive assessment of chronic hepatitis C. Preliminary results

BACKGROUND AND AIMS

The current study aims to evaluate the performance of a new elastographic method (ARFI) in noninvasive fibrosis assessment and to compare it to another validated technology (transient elastography, TE).

METHOD

112 consecutive chronic hepatitis C patients (histologically proven according to the Metavir scoring system: 12.5% F0, 26.6% F1, 16.1% F2, 7.1% F3, 37.5% F4) were prospectively included in this study. They were examined on the same day, using both ARFI (with shear wave velocity--SWV-quantification) and TE (with liver stiffness quantification).

RESULTS

SWV is correlated only with fibrosis (r=0.717, p less than 0.0001) and necroinflammatory activity (r=0.328, p=0.014), but not with steatosis (r=0.122, p=0.321). There is a significant increase of SWV in parallel with the increase in the fibrosis stage: 1.079+/-0.150 (F0-F1), 1.504+/-0.895 (F2), 1.520+/-0.575 (F3), 2.552+/-0.782 (F4), p<0.0001, but there is a certain degree of overlap between the consecutive stages F1-F2 (p=0.072), F2-F3 (p=0.965). SWV cut-off values (m/s) that were predictive for each fibrosis stage were: 1.19 (F more or equal to 1), 1.34 (F>or=2), 1.61 (F more or equal to 3) and 2.00 (F4). AUROC for ARFI vs TE were: 0.709 vs 0.902, p=0.006 (F>or=1), 0.851 vs 0.941, p=0.022 (F>or=2), 0.869 vs 0.926, p=0.153 (F>or=3) and 0.911 vs 0.945, p=0.331 (F4).

CONCLUSIONS

ARFI allows SWV quantification, in strong correlation with the fibrosis stage. Steatosis does not influence SWV. The maximal performance of the method consists of the prediction in severe fibrosis and cirrhosis. The diagnostic accuracy is strongly comparable to TE only for the prediction of severe fibrosis and cirrhosis, whereas for earlier stages, TE performs better.

Prevalence, histology, endoscopic treatment and long-term follow-up of large colonic polyps and laterally spreading tumors. The Romanian experience

AIMS

We report the prevalence, histological aspect, endoscopic treatment and follow-up of colonic polyps of 2 cm or larger and of laterally spreading tumors (LSTs) in an eastern European country.

METHODS

All consecutive colonoscopies carried out over a 1-year period (3,856) in the Endoscopy Department of the 3rd Medical Clinic Cluj-Napoca were evaluated. Fifty-two polyps and 12 LSTs of >=2cm diameter were found. Size, location and histological aspect of large colonic polyps and LSTs were assessed. Endoscopic or surgical resection was recorded. An extensive endoscopic and histological follow-up was performed.

RESULTS

Median size of polyps was 32mm and of LSTs 41mm. Invasive carcinoma was found in 7 polyps (20.6%) and in 4 LSTs (28.6%). Thirty-six polyps were endoscopically resected (69.2%). A complete endoscopic excision was performed in 35 polyps (98.6%). Histological complete resection was achieved in 30 polyps (83.3%). Thirteen polyps were surgically resected (25%). Eight LSTs were endoscopically resected (64.3%) using endoscopic piecemeal resection (EPMR). A complete endoscopic excision was performed in three LSTs (37.5%). Three LSTs were surgically resected (21.5%). In the polyp group, one patient presented endoscopic recurrence (16.6%) at 6 months follow-up. In the LST group, two invasive recurrences were present at 3 and 30 months of follow-up.

CONCLUSIONS

A complete resection can be performed in the majority of large polyps. LSTs larger than 50mm, incomplete resection and superficial invasive carcinoma were correlated with endoscopic recurrence. EPMR might be a curative method for LSTs but an accurate endoscopic diagnosis and long-term endoscopic follow-up are mandatory.

Analysis of histopathological changes that influence liver stiffness in chronic hepatitis C. Results from a cohort of 324 patients

AIM

The current study aims to assess the role of the histological parameters in liver biopsy for explaining the variance of liver stiffness, as well as the performance of transient elastography in quantifying liver fibrosis in patients with chronic hepatitis C.

METHODS

324 consecutive CHC patients were prospectively included in this study. All of them had positive HCV-RNA in serum and had underwent percutaneous liver biopsy for grading and staging the diseases (METAVIR scoring system). All were referred to liver stiffness measurement 1 day prior to biopsy.

RESULTS

Liver stiffness values were strongly correlated with fibrosis (r=0.759, p<0.0005). They also correlated with steatosis (r=0.255, p<0.0005), necroinflammatory activity (r=0.378, p<0.0005) and hepatic iron deposition (r=0.143, p=0.03). The univariate regression analysis demonstrated that fibrosis (sq.R=0.610, p<0.0005), activity (sq.R=0.145, p<0.0005) and steatosis (sq.R=0.037, p=0.002) were correlated with liver stiffness. In multiple regression analysis, all three variables independently influenced liver stiffness: fibrosis (p<0.0005), activity (p=0.039) and steatosis (p=0.025). Together they explained 62.4% of the variance of the liver stiffness. The areas under ROC curve for the diagnosis of fibrosis F > or =1, F > or =2, F > or =3, and F=4 were 0.936, 0.862, 0.910 and 0.938, for the cut-off values of 4.9 kPa, 7.4 kPa, 9.1 kPa and 11.85 kPa respectively.

CONCLUSIONS

Transient elastography is a useful method for chronic hepatitis C assessment. Fibrosis is the main predictor of liver stiffness, but activity and steatosis also influence liver stiffness.

Metabolic syndrome, insulin resistance and adiponectin level in patients with chronic hepatitis C

AIMS

To assess insulin resistance and adiponectin profile in patients with chronic hepatitis C (CHC), according to the presence or absence of metabolic syndrome (MS).

PATIENTS AND METHODS

One hundred and fifty-two patients with histologically proven CHC, genotype I were prospectively studied. Parameters of MS according to the IDF criteria were evaluated. Insulin resistance was established by homeostasis model assessment (HOMA-IR]. An index > or = 2.0 was designated as IR and > or = 4 as prediabetic state. Serum adiponectin levels were measured by ELISA:

RESULTS

MS was found in 61.48% of cases. HOMA-IR was significantly higher in patients with CHC and MS vs those without MS (7.88 +/- 1.11 vs 4.29 +/- 0.5, p=0.023]. Adiponectin levels had an inverse behaviour (9,946.1 +/- 5,811 ng/ml vs 13,215.5 +/- 815.5 ng/ml, p< 0.001]. By multiple linear regression analysis the independent predictors associated with HOMA-IR > or = 4 in patients with CHC and MS were visceral obesity, adiponectin levels, activity and degree of steatosis. Only visceral obesity and HOMA-IR were independently associated with adiponectin. A significant negative correlation was established between adiponectin and insulin (r = -0.169, p=0.003] and between adiponectin and HOMA-IR (r = -0.188, p=0.02].

CONCLUSIONS

CHC with MS was associated with a higher insulin resistance and lower adiponectin level. Adiponectin level and insulin resistance were significantly correlated.

The FibroTest value in discriminating between insignificant and significant fibrosis in chronic hepatitis C patients. The Romanian experience

AIM

To assess the diagnostic value of FibroTest to discriminate between insignificant and significant fibrosis in order to avoid the liver biopsy currently used for selection of chronic hepatitis C patients eligible for antiviral therapy.

PATIENTS AND METHODS

A retrospective study was carried out in 206 chronic hepatitis C patients with liver biopsy performed before starting antiviral therapy and concomitant serum stored at -80 degrees C. Liver fibrosis was evaluated according to the METAVIR scoring system on a scale of F0 to F4. Biochemical markers assessed were: alpha 2 macroglobulin (alpha 2-MG), apolipoprotein A1 (Apo-A1), haptoglobin (Hapto), gamma-glutamyltransferase (GGT), total bilirubin (TB). The FibroTest score was computed after adjusting for age and gender. Predictive values and ROC curves were used to assess the accuracy of FibroTest results.

RESULTS

Alpha 2-MG, apo-A1, Hapto and gender were independent predictors for significant fibrosis. For FibroTest the observed area under ROC (ObAUROC) for the discrimination between minimal or no fibrosis (F0-F1) and significant fibrosis (F2-F4) was 0.782 (+/- 95 CI: 0.716-0.847) for a cutoff value 0.47. The sensitivity (Se), specificity (Sp), positive predictive value (PPV) and negative predictive value (NPV) of the FibroTest to differentiate significant from insignificant fibrosis were 80.2; 63.2; 78.9 and 65.8, respectively. The adjusted AUROC (AdAUROC) according to the prevalence of each individual stage of fibrosis was 0.856.

CONCLUSION

FibroTest could be an alternative to biopsy in most patients with chronic hepatitis C. It requires a strict adherence and observance of the technical recommendations for the assays of biochemical markers in order to avoid analytical variability.

Steatosis in hepatitis C virus infection. Response to anti-viral therapy

BACKGROUND

Steatosis is a frequent feature of hepatitis-C-virus (HCV) infection. Steatosis may be an important cofactor in both accelerating fibrosis and increasing liver necroinflammatory activity in chronic hepatitis C. Several studies suggested that steatosis induces resistance to interferon and ribavirin combination treatment.

AIM

to assess the prevalence of steatosis in chronic HCV-infection and the host factors associated with steatosis, to estimate the impact of steatosis on liver fibrosis, and to evaluate the response to antiviral therapy in patients with HCV-infection and steatosis.

MATERIAL AND METHOD

A retrospective study was performed on 37 patients with chronic active HCV-infection treated with interferon and ribavirin: 21 women and 16 men, mean age 46.97 years. Presence of metabolic syndrome was assessed according to the ATPIII criteria. Cobas Amplicor HCV-Test was used to detect HCV-RNA. Steatosis was graded using the Brunt system.

RESULTS

Prior to the antiviral treatment, steatosis was present in 26 out of 37 patients (70%). Patients with steatosis were older, especially those with associated metabolic syndrome. Fibrosis stage was significantly advanced in patients with steatosis. Lower baseline viremia correlated with sustained response both in patients with and without steatosis. Absence of baseline steatosis was associated with higher biochemical and virological sustained response. None of the patients with metabolic syndrome had a sustained response to antiviral therapy. In all patients, the stage of fibrosis did not significantly improve 6 months after cessation of the antiviral treatment.

CONCLUSION

Steatosis is a frequently encountered histological feature in chronic HCV-infection. It is associated with older age, lower virologic response and worsening fibrosis irrespective of antiviral treatment.

Ultrasonography contribution to the detection and characterization of hepatic restructuring: is the "virtual biopsy" taken into consideration?

Generally, the evolution of diffuse liver diseases is variable but quite long. Even the severe types of chronic hepatitis have a slow progression which implies decades, often over 20-30 years. Cirrhosis is the principal long time complication of chronic hepatopathies. It represents a major risk factor for the development of hepatocellular carcinoma. Ultrasonography plays an important role among the methods used for detecting diffuse liver diseases, for placing them and identifying supplementary risk factors for carcinogenesis and of hepatocellular carcinoma itself. The two- and especially the three-dimensional exploration allow the characterization of hepatic texture and the identification of certain changes which may suggest hepatic restructuring.

Eosinophilic ascites in a patient with toxocara canis infection. A case report

We report the case of a young female patient, admitted for a recent ascites of unknown origin. The acute onset was with colicky abdominal pain and peritoneal effusion, which led to the suspicion of perforated ulcer. A diagnostic laparoscopy was performed which showed free peritoneal fluid and normal abdominal viscera. At upper gastro-intestinal endoscopy, performed a few days later, patchy erythema in the antral region and duodenal edema were revealed. Duodenal biopsies showed marked eosinophilic infiltration. The ascitic fluid was straw coloured, sterile with 90% eosinophils. Eosinophilic gastroenteritis was suspected, but differential diagnosis required the exclusion of migrant parasites. The stool exams were negative but serology for Toxocara antibodies was positive. The treatment with albendazole (Zentel 400 mg twice a day for 5 days) led to the disappearance of signs and symptoms. The eosinophilic infiltrate of the gut was absent in duodenal biopsies taken two months later.

Tumeur mélanocytaire méningée primitive de grade intermédiaire : confrontation radio-pathologique

A case of primary meningeal intermediate grade melanocytic neoplasm involving the right C2 nerve root is presented. MRI findings may suggest this rare entity, especially when an extra-axial lesion is located in the posterior fossa or cervical spinal canal and demonstrates shortening of both T1 and T2. Eventually, definitive diagnosis relies on histology which demonstrates spindle-shaped melanocytic cells that are Fontana stained and positive for HMB:45 antigen. Cellularity, pleomorphism, mitotic rate, proliferation index and invasiveness are useful criteria to distinguish among the spectrum of primary melanocytic tumors of the central nervous system ranging from melanocytoma to malignant melanoma.

Risk factors for colorectal cancer: an epidemiologic descriptive study of a series of 333 patients

AIM

The purpose of the research was to evaluate several risk factors for colonic neoplasia and to institute a specialized colorectal cancer (CRC) registry in the 3rd Medical and Surgical Clinics Cluj-Napoca.

MATERIAL AND METHODS

The study comprised 333 patients,155 women, mean age 61.32 +/- 12.42 years and 178 men, mean age 64.31 +/- 10.39 years, admitted to the 3rd Medical Clinic and 3rd Surgical Clinic Cluj-Napoca and diagnosed with CRC between January 2001 - September 2003. The diagnosis was made on the basis of clinical, endoscopical and histopathological findings. Age, geographical patterns, tumor location, family history, personal history and several lifestyle factors: dietary habits (intake of fat and red meat), long term smoking (more than 20 years), heavy alcohol consumption were analyzed. Evaluation was made using family history and epidemiologic lifestyle questionnaires.

RESULTS

CRC occurred more frequently in the 7th decade. There was a strong correlation between age and CRC development. In the 5th decade, females developed CRC more frequently than males. The median age for developing right-sided tumors was significantly higher in males. Patients living in an urban area were dominant (69%). Family history was present in 1/3 of females and 1/4 of males. Personal history of colon polyps was more common in men, particularly among smokers for more than 20 years and among those with an excessive intake of fat. The cholecystectomized women had an increased frequency of sigmoidian tumors. All the patient's information was included in a specialized colon cancer registry.

CONCLUSION

High fat intake and cigarette smoking favour colon polyp development. CRC development and location of the tumor are associated with an older age (in men) and personal history of cholecystectomy (in women). Inheritance was significant in our study group.

[Management of childhood obesity]

The prevalence of obesity is currently increasing in children and young adolescents in France, and affects about 10 to 14% of them. Therapeutic objectives should aim to improve, on the long-term, the weight/body mass index curve. Restrictive diet and weight loss should not be the primary target. The focus has to be on a balanced healthy diet, tailored to children growth, associated with a regular physical activity. Children weight management should be within the usual life conditions, taking into account familial and social environmental conditions, through a multidisciplinary team approach as those implemented in our paediatric medical centre. The objectives, management steps and current results of our therapeutic educational project are described.

Evolution of GH secretion in urine during an in-patient slimming course in obese children

OBJECTIVE

To estimate the change in GH excretion in urine (GH-U) during a slimming course, and if increased, to assess the components of the course related to the increase in obese children.

DESIGN

Observational follow-up study of patients admitted for primary obesity to an in-patient slimming course lasting at least 10 weeks.

SUBJECTS

48 complete observations out of 54 consecutive pre-pubertal patients admitted to a paediatric centre for treatment of primary obesity (BMI greater than the 90th percentile of the national reference curves).

MEASUREMENTS

GH excretion in urine by immunoradiometric assay, at entry and after 10 weeks, various anthropometric measurements, nutritional intake and departure from the prescribed diet, time spent in physical activity, sleep duration.

RESULTS

A mean decrease of 0.90 standard deviations for BMI was accompanied by a 34% increase of GH-U. Time spent in physical activity was the only component of the course found to be related to the magnitude of GH-U increase.

CONCLUSION

The results of this observational study confirm that GH-U is increased after a slimming course in children, and suggest that physical activity is a major contributor to the restoration of normal GH-U levels.

Dual energy X-ray absorptiometry of the hand and wrist--a possible technique to assess skeletal maturation: methodology and data in normal youths

Ninety five normal Caucasian subjects (51F, 44M) aged from 2 to 25 y were measured at the hand and wrist level with a small DXA system (pDEXA) in order to obtain the normal values of the bone mineral content (BMC), density (BMD) and projected area (A) of carpal (c) and metacarpal (m) bones. BMDc ranged from 0.065 +/- 0.007 g/cm2 to 0.365 +/- 0.035 g/cm2 in females and 0.425 +/- 0.040 g/cm2 in males. It presented a sharp change of increase rate at 15.5 and 17 y of age in girls and boys, respectively. Ac presented the same kind of evolution as BMDc, but had a larger value dispersion. The second metacarpal bone had the highest BMCm value in 85% of females and 90% of males. The sum of BMCmi or Ami values (i = 1-5) and the projected mean density of the 5 metacarpal bones was well correlated with BMCc, Ac and BMDc, respectively (r > 0.90). A volumetric mineral density, dmi, calculated for each of these bones, approximated to a cylinder, was correlated with age (r > 0.85).

Nonclassical adrenal hyperplasia due to 21-hydroxylase-deficiency: does genotyping predict the clinical manifestation?

8 patients of 7 families with nonclassical adrenal hyperplasia (NCAH) were analysed for defects of the 21-hydroxylase-B-gene. As the defects were small or rare, complete molecular genetic diagnostic up to sequencing of this gene was necessary to detect the genotype, which then was associated with the phenotype. However, mutations in 4 alleles from 3 families are still undetectable. Thus, correct prenatal diagnosis in NCAH-families without index patient remains difficult.

Evaluation of the Elbs Persulfate Oxidation Reaction for the Preparation of Aryloxyphenoxypropionate Herbicides

A new, simple method for the preparation of several 4-( aryloxy )phenols (2a-d) and alkyl 2-(4-hydroxyphenoxy)propionates (3a,b) is described. These compounds are key precursors for the synthesis of important aryloxyphenoxypropionate herbicides (1a-d). The method uses the Elbs persulfate oxidation to convert phenol into 4-hydroxyphenyl sulfate (5). The free hydroxy group is then reacted with various aryl halides and alkyl 2-halopropionates. Mild hydrolysis of the sulfate group with boiling acetic acid then gives the products (2a-d) and (3a,b), generally in modest to good yield.

Spectroscopic characterization of conformational differences between PrPC and PrPSc: an alpha-helix to beta-sheet transition

Although no chemical modifications have been found to distinguish the cellular prion protein PrPC from its infectious analogue PrPSc, spectroscopic methods such as Fourier transform infrared (FTIR) spectroscopy reveal a major conformational difference. PrPC is rich in alpha-helix but is devoid of beta-sheet, whereas PrPSc is high in beta-sheet. N-terminal truncation of PrPSc by limited proteolysis does not destroy infectivity but it increases the beta-sheet content and shifts the FTIR absorption to lower frequencies, typical of the cross beta-pleated sheets of amyloids. Thus the formation of PrPSc from PrPC involves a conformational transition in which one or more alpha-helical regions of the protein is converted to beta-sheet. This transition is mimicked by synthetic peptides, allowing predictions of domains of PrP involved in prion diseases.

Conversion of alpha-helices into beta-sheets features in the formation of the scrapie prion proteins

Prions are composed largely, if not entirely, of prion protein (PrPSc in the case of scrapie). Although the formation of PrPSc from the cellular prion protein (PrPC) is a post-translational process, no candidate chemical modification was identified, suggesting that a conformational change features in PrPSc synthesis. To assess this possibility, we purified both PrPC and PrPSc by using nondenaturing procedures and determined the secondary structure of each. Fourier-transform infrared (FTIR) spectroscopy demonstrated that PrPC has a high alpha-helix content (42%) and no beta-sheet (3%), findings that were confirmed by circular dichroism measurements. In contrast, the beta-sheet content of PrPSc was 43% and the alpha-helix 30% as measured by FTIR. As determined in earlier studies, N-terminally truncated PrPSc derived by limited proteolysis, designated PrP 27-30, has an even higher beta-sheet content (54%) and a lower alpha-helix content (21%). Neither PrPC nor PrPSc formed aggregates detectable by electron microscopy, while PrP 27-30 polymerized into rod-shaped amyloids. While the foregoing findings argue that the conversion of alpha-helices into beta-sheets underlies the formation of PrPSc, we cannot eliminate the possibility that an undetected chemical modification of a small fraction of PrPSc initiates this process. Since PrPSc seems to be the only component of the "infectious" prion particle, it is likely that this conformational transition is a fundamental event in the propagation of prions.

Ablation of the prion protein (PrP) gene in mice prevents scrapie and facilitates production of anti-PrP antibodies

Mice, homozygous for prion protein (PrP) gene ablation (Prn-p0/0), develop normally and remain well > 500 days after inoculation with murine scrapie prions. In contrast, wild-type mice developed scrapie < 165 days after inoculation and most Prn-p0/+ mice, heterozygous for disruption of the PrP gene, exhibited signs of central nervous system dysfunction between 400 and 465 days after inoculation. In situ immunoblots showed widespread deposition of scrapie PrP (PrPSc) in the brains of both wild-type Prn-p+/+ and Prn-p0/+ mice, while neither cellular PrP (PrPC) nor PrPSc was detected in the brains of Prn-p0/0 mice. In contrast to Prn-p+/+ and Prn-p0/+ mice, Prn-p0/0 mice failed to propagate prion infectivity as measured by bioassays. Syrian hamster (SHa) PrP transgenes rendered Prn-p0/0 mice susceptible to prions containing SHaPrPSc. Immunization of Prn-p0/0 mice with purified, infectious mouse or SHa prions dispersed in Freund's adjuvant produced antisera that bound mouse, SHa, and human PrP on Western blots. Presumably, the lack of PrPC expression in Prn-p0/0 mice prevents them from becoming tolerant to the immunogen. The resistance of Prn-p0/0 mice to developing scrapie after inoculation with murine prions supports the hypothesis that PrPSc is essential for both transmission and pathogenesis of the prion diseases.