Cat scratch disease in an immunosuppressed patient with systemic lupus erythematosus.

Cat scratch disease is an infectious disorder transmitted by cats that typically affects children and young adults. Immunosuppression is a well-known risk factor for the development of severe and atypical forms of the disease; hence it is under-diagnosed in patients with compromised immunity. We are reporting the first case of cat scratch disease, which presented as fever and fatigue, in a patient with systemic lupus erythematosus while receiving immunosuppressant therapy after a kidney transplant.

Hepatitis B virus quasispecies evolution after liver transplantation in patients under long-term lamivudine prophylaxis with or without hepatitis B immune globulin.

AIMS: To investigate an optimal long-term prophylactic strategy for prevention of hepatitis B virus (HBV) recurrence after liver transplantation, we conducted a randomized study of 29 transplant recipients receiving a short course of hepatitis B immune globulin (HBIg) + lamivudine (LAM), followed by randomization to long-term prophylaxis with LAM with or without HBIg. METHODS: The efficacy and safety, and impact on survival and HBV recurrence of these 2 prophylactic regimens were compared over a mean period of 10 years. In patients with viral recurrence, the HBV quasispecies in the surface/polymerase region were studied by ultra-deep pyrosequencing (UDPS). RESULTS: The 10-year survival rate was 76% and was not affected by the type of prophylaxis. Four patients had hepatitis B surface antigen (HBsAg) recurrence within the first 48 months after orthotopic liver transplantation (OLT). HBsAg-positive and -negative patients showed similar mean survival times, with no differences between the 2 regimens. Low HBV DNA levels were transiently detected in 32% of HBsAg-negative patients. UDPS showed major changes after OLT in the HBV quasispecies of patients with viral recurrence, which may be explained by a "bottleneck" effect of OLT together with prophylactic therapy. CONCLUSION: Long-term survival after OLT in end-stage chronic hepatitis B patients was good with both prophylactic strategies. However, low, transient HBV DNA levels were detected even in the absence of HBsAg, showing the importance of continuing HBV prophylaxis.

Pro- and anti-inflammatory cytokine gene single-nucleotide polymorphisms in inflammatory bowel disease.

Anti-inflammatory cytokines have an important role in disease, tumour and transplant processes. Alterations in the regulation of several cytokines have been implicated in a variety of inflammatory disorders, including IBD (inflammatory bowel disease) [Crohn's disease (CD) and ulcerative colitis (UC)]. Cytokine polymorphisms are also known to affect the level of gene expression. Thus, the aim of this study was to determine the relationship between cytokine polymorphisms and the IBD pathologies in a Spanish population. Polymorphisms analysis was performed using PCR-SSOP using a microbeads luminex assay. The following polymorphisms were determined: TNFα [-238G/A (rs361525) and -308G/A (rs1800629)], IFNγ [+874A/T (rs62559044)], TGFß [+869C/T (rs1982073) and +915G/C (rs1800471)], IL10 [-1082A/A (rs1800896), -592A/C (rs1800872), -819C/T (rs1800871)], IL6 [-174C/G (rs1800795)], IL12p40 [3'UTR -1188A/C (rs3212227)], IL1α [-889C/T (rs1800587)], IL1ß [-511C/T (rs1143634) and +3962C/T (rs1143633)], IL1R [Pst-1 1970C/T] and IL1RA [Mspa-1 11100C/T]. No statistical differences in TNFα, IFNγ, TGFß, IL10, IL6, IL1α, IL1ß, IL1R and IL1Ra genotypes and allele distributions between the IBD groups and healthy controls were found. However, we observed significant differences in the 3'UTR -1188A/C polymorphism of IL12p40. So -1188A allele was increased in patients with UC and the -1188C allele (high IL12p40 production) was increased in patients with CD with respect to controls. These data are in concordance with the fact that CD has been shown to be associated with a Th1 T-cell-mediated inflammation model and high IL12/IFNγ production at histological affected sites. These data suggest that cytokine polymorphisms in TNFα, IFNγ, TGFß, IL10, IL6 and IL1α, IL1ß, IL1R and IL1Ra cytokine gene do not seem to be relevant in IBD susceptibility and IL12p40 3'UTR -1188A/C polymorphism seems to be associated with a differential IBD development.

Should IFN-γ, IL-17 and IL-2 be considered predictive biomarkers of acute rejection in liver and kidney transplant? Results of a multicentric study.

Acute rejection (AR) remains a major challenge in organ transplantation, and there is a need for predictive biomarkers. In the present multicenter study, we prospectively examined a series of biomarkers in liver and kidney recipients. Intracellular expression of IFN-γ, IL-17 and IL-2 and IL-17 soluble production were evaluated both pre-transplantation and post-transplantation (1st and 2nd week, 1st, 2nd and 3rd month). 142 transplant patients (63 liver/79 kidney) were included in the study. Twenty-eight recipients (14 liver/14 kidney) developed AR. Pre- and post-transplantation intracellular expression of %IFN-γ(+) in CD4(+)CD69(+) and in CD8(+)CD69(+) and soluble IL17 identified liver and kidney transplant patients at high risk of AR. Pre-transplantation, %IL-2(+) in CD8(+)CD69(+) also identified kidney patients at high risk. We constructed pre- and post-transplantation risk prediction models, based on a composite panel of biomarkers, which could provide the basis for future studies and will be a useful tool for the selection and adjustment of immunosuppressive treatments.

Genetic polymorphisms of tumour necrosis factor alpha (TNF-α) promoter gene and response to TNF-α inhibitors in Spanish patients with inflammatory bowel disease.

Tumour necrosis factor alpha (TNF-α) has an important role in inflammatory response. Alterations in the regulation of TNF-α have been implicated in a variety of inflammatory disorders, including Inflammatory bowel disease (IBD). Indeed, a common treatment for IBD is the use of TNF-α inhibitors. Polymorphisms in the TNF-α promoter region are known to affect the level of gene expression. Our aim was to investigate the influence of these single nucleotide polymorphisms (SNPs) in TNF-α promoter gene play in the risk of IBD in a Spanish population and their individual response to anti-TNF-α treatment. DNA samples from patients with IBD and controls were screened for TNF-α -238G/A (rs361525) and -308G/A (rs1800629) SNPs by PCR-SSOP using a microbeads luminex assay and compared with response to TNF-α inhibitors. There were not statistical differences in -238G/A and -308G/A allele and genotype frequencies between patients. However, we found an increased frequency of -308A allele and -308GA genotype in these nonresponders patients to TNF-α inhibitors with respect to responders patients (Pc < 0.05). This -308GA genotype has been classified as high producer of this cytokine. This fact could actually be interesting to explain the different response of patients with IBD with respect to TNF-α inhibitors. TNF-α promoter gene polymorphism does not seem to play a role in IBD susceptibility, but particular TNF-α genotypes may be involved in the different responses to TNF-α inhibitor treatment in Spanish patients with IBD.

Microbial communities adhering to the obverse and reverse sides of an oil painting on canvas: identification and evaluation of their biodegradative potential.

In this study, we investigated and compared the microbial communities adhering to the obverse and the reverse sides of an oil painting on canvas exhibiting signs of biodeterioration. Samples showing no visible damage were investigated as controls. Air samples were also analysed, in order to investigate the presence of airborne microorganisms suspended in the indoor atmosphere. The diversity of the cultivable microorganisms adhering to the surface was analysed by molecular techniques, such as RAPD analysis and gene sequencing. DGGE fingerprints derived from DNA directly extracted from canvas material in combination with clone libraries and sequencing were used to evaluate the non-cultivable fraction of the microbial communities associated with the material. By using culture-dependent methods, most of the bacterial strains were found to be common airborne, spore-forming microorganisms and belonged to the phyla Actinobacteria and Firmicutes, whereas culture-independent techniques identified sequenced clones affiliated with members of the phyla Actinobacteria and Proteobacteria. The diversity of fungi was shown to be much lower than that observed for bacteria, and only species of Penicillium spp. could be detected by cultivation techniques. The selected strategy revealed a higher microbial diversity on the obverse than on the reverse side of the painting and the near absence of actively growing microorganisms on areas showing no visible damage. Furthermore, enzymatic activity tests revealed that the most widespread activities involved in biodeterioration were esterase and esterase lipase among the isolated bacterial strains, and esterase and N-acetyl-ß-glucosaminidase among fungi strains.

Nanocomposite synthesis by absorption of nanoparticles into macroporous hydrogels. Building a chemomechanical actuator driven by electromagnetic radiation.

Macroporous hydrogels irreversibly absorb solid nanoparticles from aqueous dispersions. A nanocomposite is made using a macroporous thermosensitive hydrogel (poly(N-isopropylacrylamide-co-(2-acrylamido-2-methyl propane sulfonic acid)) (poly(NIPAm-co-AMPS)) and conductive polymer (polyaniline, PANI) nanoparticles (PANI NPs). Macroporous gels of poly(NIPAm-co-AMPS) were made by a cryogelation technique. NPs of PANI were produced by precipitation polymerization. It is found that PANI NPs are easily absorbed into the macroporous hydrogels while conventional non-porous hydrogels do not incorporate NPs. It is shown that PANI NPs, dispersed in water, absorb NIR laser light or microwave radiation, increasing their temperature. Upon irradiation of the nanocomposite with microwaves or NIR laser light, the PANI NPs heat up and induce the phase transition of the thermosensitive hydrogel matrix and the internal solution is released. Other nano-objects, such as gold nanorods and PANI nanofibers, are also easily incorporated into the macroporous gel. The resulting nanocomposites also suffer a phase transition upon irradiation with electromagnetic waves. The results suggest that, using a thermosensitive matrix and conducting nanoparticles, mechanical/chemical actuators driven at a distance by electromagnetic radiation can be built. The sensitivity of the nanocomposite to electromagnetic radiation can be modulated by the pH, depending on the nature of the incorporated nanoparticles. Additionally, it is possible to make systems which absorb either NIR or microwaves or both.

Spectroscopic evidence for intermediate species formed during aniline polymerization and polyaniline degradation.

Spectroscopic methods are used to investigate the formation of low molecular mass intermediates during aniline (ANI) oxidation and polyaniline (PANI) degradation. Studying ANI anodic oxidation by in situ Fourier transform infrared spectroscopy (FTIRS) it is possible to obtain, for the first time, spectroscopic evidence for ANI dimers produced by head-to-tail (4-aminodiphenylamine, 4ADA) and tail-to-tail (benzidine, BZ) coupling of ANI cation radicals. The 4ADA dimer is adsorbed on the electrode surface during polymerization, as proved by cyclic voltammetry of thin PANI films and its infrared spectrum. This method also allows, with the help of computational simulations, to assign characteristic vibration frequencies for the different oxidation states of PANI. The presence of 4ADA retained inside thin polymer layers is established too. On the other hand, FTIRS demonstrates that the electrochemically promoted degradation of PANI renders p-benzoquinone as its main product. This compound, retained inside the film, is apparent in the cyclic voltammogram in the same potential region previously observed for 4ADA dimer. Therefore, applying in situ FTIRS is possible to distinguish between different chemical species (4ADA or p-benzoquinone) which give rise to voltammetric peaks in the same potential region. Indophenol and CO(2) are also detected by FTIRS during ANI oxidation and polymer degradation. The formation of CO(2) during degradation is confirmed by differential electrochemical mass spectroscopy. To the best of our knowledge, this is the first evidence of the oxidation of a conducting polymer to CO(2) by electrochemical means. The relevance of the production of different intermediate species towards PANI fabrication and applications is discussed.

Clinical and economic burden of community-onset multidrug-resistant infections requiring hospitalization.

OBJECTIVES: To analyze the clinical and economic burden of community-acquired (CA) or community-onset healthcare-associated (COHCA) multidrug-resistant (MDR) infections requiring hospitalization. METHODS: Case-control study. Adults admitted with CA or COHCA MDR infections were considered cases, while those admitted in the same period with non-MDR infections were controls. The matching criteria were source of infection and/or microorganism. Primary outcome was 30-day clinical failure. Secondary outcomes were 90-day and 1-year mortality, hospitalization costs and resource consumption. RESULTS: 194 patients (97 cases and 97 controls) were included. Multivariate analysis identified age (odds ratio [OR], 1.07, 95% confidence interval [CI], 1.01-1.14) and SOFA score (OR, 1.45, CI95%, 1.15-1.84) as independent predictors of 30-day clinical failure. Age (hazard ratio [HR] 1.09, 95%CI, 1.03-1.16) was the only factor associated with 90-day mortality, whereas age (HR 1.06, 95%CI, 1.03-1.09) and Charlson Index (HR 1.2, 95%CI, 1.07-1.34) were associated with 1-year mortality. MDR group showed longer hospitalization (p<0.001) and MDR hospitalization costs almost doubled those in the non-MDR group. MDR infections were associated with higher antimicrobial costs. CONCLUSIONS: Worse economic outcomes were identified with community-onset MDR infections. MDR was associated with worse clinical outcomes but mainly due to higher comorbidity of patients in MDR group, rather than multidrug resistance.

[Intragastric balloon in obesity treatment]. / Balón intragástrico en el tratamiento de la obesidad.

Obesity is considered a chronic and epidemic illness, hece difficult to treat. As conservative treatment has a high rate of failure, and considering morbimortality and sequels of surgery, less invasive techniques appeared to contribute to the treatment of this illness. The most implanted technique nowadays is the Intragastric Balloon, considered more efficient as conservative treatments and with less risks tan surgery, but having today a lack of consensus on indications and few information on his limitations, while its apparition in medias promote an important expansion in the 4 last years. In this publication, we do a critical revision, and describe limitations of this treatment, based on the evidences given by literature. We conclude this revision with some recommendations concerning the technique and indications, material and human requiring, need of a Multidisciplinary Team, as well as an adequate control and following.

Role of liver transplantation in the management of unresectable neuroendocrine liver metastases.

UNLABELLED: The use of OLT in the management of liver metastases of any origin is highly controversial, as most patients receiving a transplant for this indication display poor results owing to early tumor spread secondary to the effects of immunosuppression. However, as they have a better biological behavior, neuroendocrine (NE) tumors may be a good indication for OLT. Our aim was to present our experience in the management of unresectable liver metastases of tumors of NE origin. PATIENTS AND METHODS: Between January 1996 and April 2006, 10 patients underwent OLT for unresectable liver metastases of a neuroendocrine origin, accounting for 1.2% of all transplants performed to date in our unit (n = 626). The most common location of the primary tumor was the pancreas in six cases: three in the pancreatic tail--one carcinoid tumor, one gastrinoma, and one nonfunctioning NE [NF-NE] tumor; and three cases in the pancreatic head--three NF-NE tumors. In the remaining four cases, including three carcinoid tumours and one NF-NE tumors, two were located in the small bowel (at the ileum and ileocecal valve) and two in the lung. The liver metastases were synchronous with the primary tumor in seven cases and metachronous in three cases. RESULTS: The morbidity rate was 75% and the mortality rate, 10% (n = 1). The tumor recurrence rate was 33% with 1- and 3-year survival rates of 86% and 57%, respectively.

Clinical evolution in the first 3 months of patients after liver transplantation in maintenance phase converted from mycophenolate mofetil to mycophenolate sodium due to gastrointestinal complications.

The enteric-coated mycophenolate sodium (EC-MPS) is a new formulation of mycophenolic acid with a gastro-resistant enteric coating, which releases the drug in the intestine, reducing the incidence of the gastrointestinal (GI) adverse effects. The present work provided a summary of 20 patients with liver transplantation and more than a 1 year of treatment with mycophenolate mofetil (MMF) who, after presentation of GI complications, were converted to EC-MPS. The patients were followed over a 3-month period after beginning EC-MPS treatment. The mean age of the cohort was 53 +/- 10 years and included 75% men. The reasons for transplantation were ethanol cirrhosis (70%), hepatitis C cirrhosis (30%), hepatocarcinoma (5%), and Wilson's disease (5%). At baseline, all patients were being treated with cyclosporine (CsA). CsA doses and levels were reduced during follow-up: baseline dose 179 mg/day versus 143 mg/day at 3 months; levels: 90.4 ng/mL versus 85.8 ng/mL, respectively (P = .017). The administered dose of EC-MPS was 720 mg/day in all cases. The GI complications at baseline were: diarrhea 60% (92% moderate-severe), abdominal discomfort 60% (58% moderate), abdominal pain 45% (44% moderate-severe), gas 40% (38% moderate-severe), nausea 20% (25% moderate), and dyspepsia 20% (mild). After 3 months of EC-MPS treatment, only two patients (10%) displayed moderate diarrhea. The renal evolution was favorable, serum creatinine was reduced, and 24-hour creatinine clearance significantly increased (creatinine: 1.78 +/- 1.6 mg/dL at baseline versus 1.30 +/- 0.3 mg/dL at 3 months, P = .002; creatinine clearance: 72.8 +/- 18 mL/min versus 79.6 +/- 13 mL/min, P = .001). Conversion of MMF to EC-MPS in liver transplant recipients solved the GI tolerability problems and improved renal function during the first 3 months, probably due to the concomitant reduction of anticalcineurinic dose.

Gastrointestinal complications in liver transplant recipients: MITOS study.

INTRODUCTION: Liver transplant recipients frequently suffer gastrointestinal (GI) complications but their prevalence and their influence on quality of life remain unknown. OBJECTIVE: The objective of this study was to asses the prevalence, impact on quality of life, and management of GI complications in liver transplant recipients. PATIENTS AND METHODS: This was an epidemiologic, cross-sectional, multicenter study. Four hundred seventeen liver recipients were recruited in 14 centers. A questionnaire was filled for every patient. RESULTS: The median age of the patients was 55 years. The median time since transplantation was 4.1 +/- 4 years. Whereas 19.2% presented some GI disease before transplantation, 49.4% showed this type of complication after transplantation. Diarrhea was the most prevalent GI complication, and anorexia was the GI disorder that affected patients daily activities the most frequently. GI complications were more frequent among female patients, subjects with pretransplantation hiatal hernia, and those readmitted after transplantation. Of the patients with GI complications, 70.9% received pharmacological treatment (89.7% with gastric protectors). Immunosuppressive therapy was also modified because of GI complications. Immunosuppressive drug dose was reduced in 18.1%, transiently stopped in 3.4%, and definitively stopped in 3.4% of cases. The drug most frequently changed was mycophenolate mofetil: dose reduction, 23.6%; transient withdrawal, 5.7%; and definitive withdrawal, 6.6%. CONCLUSIONS: The prevalence of GI complications in the liver transplant population was approximately 50%. GI complications showed a significant impact on the quality of life of the patients. They were related to female gender, to pretransplantation GI pathology, and posttransplantation hospital admission. These complications were frequently managed with pharmacological therapy or with changes in immunosuppressive therapy.

Evaluation of CD86 gene polymorphism at +1057 position in liver transplant recipients.

BACKGROUND: Efficient T cell-APC interaction requires the participation of primary and co-stimulatory signals. The main co-stimulatory pathway involves the interaction of CD80 and CD86, expressed on the APCs, with their T cell counter-receptor, CD28 and CTLA-4. Recently, a G to A transition has been described at position +1057 of the CD86 gene, located in their cytoplasmic tail. METHODS: CD86 polymorphism was analyzed by sequence based typing in DNA samples obtained from 205 liver transplant recipients. Acute rejection and chronic rejection were diagnosed based upon conventional clinical, biochemical and histological criteria. RESULTS: The study of CD86 +1057 (G/A) polymorphism revealed that recipients bearing the A allele or the AA genotype have a reduced risk of acute rejection. In fact, the AA genotype was absent in the group of patients showing acute rejection episodes, whereas its frequency in those patients without acute rejection episodes was 8.8% (P=0.009, OR=0.07). This polymorphism did not reveal any association with the incidence of chronic rejection, but patients bearing the AA genotype showed a higher graft survival rate (83.3%) than those bearing the GA genotype (49.3%) or GG genotype (56.5%). CONCLUSIONS: The results of the present report suggest that the CD86 AA genotype at +1057 position could be involved in liver transplant acceptance, given that its presence is related to a decrease of acute rejection frequency and to a graft survival increase.

Early experience with customized, meal-triggered gastric electrical stimulation in obese patients.

BACKGROUND: We report our initial gastric electrical stimulation experience using the abiliti® system for the treatment of obese patients followed for 1 year. METHOD: Between March 2011 and June 2013, 27 obese patients (BMI 30 to 46 kg/m(2)) were enrolled in a prospective open label study and implanted with a gastric stimulator. The patients were provided with nutritional support, and sensor-based behavioral feedback. RESULTS: At 12 months, percent excess weight loss (%EWL) obtained was 49.3 ± 19.2 % with no significant differences between gender or age sub-groups. The %EWL data were segmented into two groups according to BMI 30-40 kg/m(2) patients (obesity grade I and II) and BMI >40 kg/m(2), with the results of weight loss being significantly higher for the lower BMI group (59.1 ± 19.5 vs. 46.7 ± 13.4, respectively, p < 0.01). One subject requested to have his device explanted, and the minor postoperative adverse events were resolved without hospital admission. All patients experienced early satiety and reduced their intake. CONCLUSIONS: After 12 months of follow-up, gastric electrical stimulation treatment appears to be a safe and effective option for weight loss in obese subjects. Long-term follow-up and further studies are warranted.

Activated Regulatory T Cells Expressing CD4(+)CD25(high)CD45RO(+)CD62L(+) Biomarkers Could Be a Risk Factor in Liver Allograft Rejection.

Activated regulatory T cells (aTregs) are nowadays a hot topic in organ transplantation to establish their role during acute rejection (AR) episodes. The aim of this multi-center study was to monitor the frequency of aTregs within the first year after transplantation in a cohort of first-time liver transplant recipients enrolled from 2010 to 2012. aTregs frequency was analyzed by means of flow cytometry. Patients who had AR showed higher levels of aTregs during first year after transplantation in comparison with patients who did not have higher levels. High levels of aTregs in liver recipients might be used as a biomarker of AR; however, further studies must be done to address the potential role of aTregs as biomarkers of AR in liver transplantation.

Long-term results of liver transplantation in familial amyloidotic polyneuropathy type I.

BACKGROUND: The aim of this article is to report our experience regarding the survival and the evolution of polyneuropathy of the extremities and autonomic dysfunction in 18 liver transplant patients with familial amyloidotic polyneuropathy type I after a mean follow-up of more than 2.5 years for 13 patients. METHODS: The actuarial survival rate of the 18 patients is 72.2% and 60.1%, respectively, at 12 and 58 months. RESULTS: In all the patients we noted clinical improvement of the polyneuropathy of the extremities and autonomic dysfunction during the first 6 months after transplant. The clinical data due to autonomic nervous system involvement showed an earlier improvement than those due to nervous motor involvement. CONCLUSIONS: In conclusion, our results suggest that liver transplant may be useful in the treatment of certain cases of familial amyloidotic polyneuropathy to stop the neurological deterioration of the patients and to avoid the fatal end of the disease.

CD28 expression on peripheral blood T lymphocytes after orthotopic liver transplant: upregulation in acute rejection.

Despite immunosuppressive treatments, acute rejection remains a significant cause of graft loss. Efficient allorecognition implicates cognate T-cell interactions and requires costimulatory signals such as those delivered via CD28. Therefore, we have studied CD28 peripheral blood T-cell expression, analyzing its possible implications in liver allograft acute rejection. Fifty-five CsA-immunosuppressed orthotopic liver recipients, with or without acute rejection (AR and NAR) were immunocytometrically monitored after transplant and thirty healthy volunteers were studied as controls. In liver recipients the absolute number of CD28+ cells fell sharply immediately after transplant, but no significant differences were detected between the AR and NAR groups either in the absolute number or in the percentage of CD28+ lymphocytes. By contrast, both CD4+CD28+ and CD8+CD28+ T-cell subsets displayed a significant increase in CD28 intensity expression in AR recipients, whereas CD28 expression was significantly downregulated in the NAR recipients. This data suggests that CD28 molecule can be important in the immunologic events preceding acute rejection and that CD28 up- or downregulation could become a useful predictive marker for acute rejection or tolerance development in liver recipients.

Studies on the interaction of dopamine beta-hydroxylase from various sources with phytohaemagglutinins.

1. Bovine adrenal medulla dopamine beta-hydroxylase, a glycoprotein with terminal mannose residues in carbohydrate moiety, did not precipitate with any lectins tested except concanavalin A. After digestion with neuraminidase, the enzyme was shown to interact with ricin, and a good correlation was found between the amount of liberated sialic acids and the extent of agglutination. This finding show either that more than one type of carbohydrate unit occurs on the protein or that three are multibranched chains in the carbohydrate moiety. 2. Dopamine beta-hydroxylase from human serum, pheochromocytoma and normal adrenal were incubated with concanavalin A, ricin, wheat germ agglutinin and lectins from Dilochos biflorus and Robinia pseudoacacia. 83% of dopamine beta-hydroxylase from pheochromocytoma was precipitated by ricin, whereas the enzyme from human serum precipitated to a lesser extent (5-15%). Neuraminidase digestion of human serum dopamine beta-hydroxylase led to an increase of precipitation with ricin. The low extent of native human serum dopamine beta-hydroxylase precipitation with ricin can be explained by the attack of plasma membrane sialidases of liver cells, whereas the greater ricin precipitation of pheochromocytoma and normal adrenal dopamine beta-hydroxylases could be due to post-mortem effects. The clinical implications of possibility of difference concerning the carbohydrate moiety structures of pheochromocytoma and normal enzymes is discussed.