Effect of large doses of parenteral vitamin D on glycaemic control and calcium/phosphate metabolism in patients with stable type 2 diabetes mellitus: a randomised, placebo-controlled, prospective pilot study.

OBJECTIVE Vitamin D (D₃) status is reported to correlate negatively with insulin production and insulin sensitivity in patients with type 2 diabetes mellitus (T2DM). However, few placebo-controlled intervention data are available. We aimed to assess the effect of large doses of parenteral D3 on glycosylated haemoglobin (HbA(₁c)) and estimates of insulin action (homeostasis model assessment insulin resistance: HOMA-IR) in patients with stable T2DM. MATERIALS AND METHODS We performed a prospective, randomised, double-blind, placebo-controlled pilot study at a single university care setting in Switzerland. Fifty-five patients of both genders with T2DM of more than 10 years were enrolled and randomised to either 300,000 IU D₃ or placebo, intramuscularly. The primary endpoint was the intergroup difference in HbA(₁c) levels. Secondary endpoints were: changes in insulin sensitivity, albuminuria, calcium/phosphate metabolism, activity of the renin-aldosterone axis and changes in 24-hour ambulatory blood pressure values. RESULTS After 6 months of D₃ supply, there was a significant intergroup difference in the change in HbA(₁c) levels (relative change [mean ± standard deviation] +2.9% ± 1.5% in the D₃ group vs +6.9% ± 2.1% the in placebo group, p = 0.041) as HOMA-IR decreased by 12.8% ± 5.6% in the D₃ group and increased by 10% ± 5.4% in the placebo group (intergroup difference, p = 0.032). Twenty-four-hour urinary albumin excretion decreased in the D₃ group from 200 ± 41 to 126 ± 39, p = 0.021). There was no significant intergroup difference for the other secondary endpoints. CONCLUSIONS D₃ improved insulin sensitivity (based on HOMA-IR) and affected the course of HbA(₁c) positively compared with placebo in patients with T2DM.

First-Trimester Placental Growth Factor in Screening for Gestational Diabetes.

OBJECTIVE The aim of this study was first to assess whether first-trimester serum concentrations of placental growth factor (PlGF) differ between patients with and without gestational diabetes (GDM) and second to test whether there is a correlation between glycosylated hemoglobin (HbA1c), a factor recently shown to be useful in predicting GDM, and PlGF. METHODS PlGF was measured at 8-14 weeks with the Kryptor Immunoassay Analyzer (Brahms, Berlin, Germany). Absolute values were converted to multiples of the median using the software provided by the Fetal Medicine Foundation London. GDM was diagnosed using internationally accepted criteria. HbA1c levels were quantified using the TOSOH G7 automated hemoglobin analyzer. RESULTS From January to December 2014, 328 women were included in the study, 51 (15.5%) of whom developed GDM. First-trimester PlGF quantification does not discriminate between women at risk to develop GDM and controls, while HbA1c is able to do so. No correlation was found between PlGF and HbA1c. CONCLUSION Our findings do not lend support to the hypothesis that early PlGF values are different in women who later develop GDM.

Treatment intensification with insulin glargine in patients with inadequately controlled type 2 diabetes improves glycaemic control with a high treatment satisfaction and no weight gain

PRINCIPLES We aimed to evaluate the efficacy of, and treatment satisfaction with, insulin glargine administered with SoloSTAR® or ClikSTAR® pens in patients with type 2 diabetes mellitus managed by primary care physicians in Switzerland. METHODS A total of 327 patients with inadequately controlled type 2 diabetes were enrolled by 72 physicians in this prospective observational study, which aimed to evaluate the efficacy of a 6-month course of insulin glargine therapy measured as development of glycaemic control (glycosylated haemoglobin [HbA1c] and fasting plasma glucose [FPG]) and weight change. We also assessed preference for reusable or disposable pens, and treatment satisfaction. RESULTS After 6 months, the mean daily dose of insulin glargine was 27.7±14.3 U, and dose titration was completed in 228 (72.4%) patients. Mean HbA1c decreased from 8.9%±1.6% (n=327) to 7.3%±1.0% (n=315) (p<0.0001), and 138 (43.8%) patients achieved an HbA1c≤7.0%. Mean FPG decreased from 10.9±4.5 to 7.3±1.8 mmol/l (p<0.0001). Mean body weight did not change (85.4±17.2 kg vs 85.0±16.5 kg; p=0.11). Patients' preference was in favour of the disposable SoloStar® pen (80%), as compared with the reusable ClickStar® pen (20%). Overall, 92.6% of physicians and 96.3% of patients were satisfied or very satisfied with the insulin glargine therapy. CONCLUSIONS In patients with type 2 diabetes insulin glargine administered by SoloSTAR® or ClikSTAR® pens, education on insulin injection and on self-management of diabetes was associated with clinically meaningful improvements in HbA1c and FPG without a mean collective weight gain. The vast majority of both patients and primary care physicians were satisfied with the treatment intensification.

STUDIES ON THE MECHANISM OF ASSEMBLY OF MURINE LEUKEMIA VIRUS

The purpose of this research was to elucidate the mechanism of assembly of retroviruses, specifically of murine leukemia virus, as studied through the treatment of virus-infected cells with interferon and through the use of temperature sensitive (ts) mutants. Our studies have shown a rapid and specific association of Rauscher murine leukemia virus (R-MuLV) precursor polyprotein Pr65('gag) with cytoskeletal elements in infected mouse fibroblasts. The Pr65('gag) associated with Nonidet P-40 (NP40)-insoluble cytoskeletal structures appeared to be subphosphorylated in comparison to NP40-soluble Pr65('gag). The association of Pr65('gag) with skeletal elements could be disrupted by extraction of the cytoskeleton with sodium deoxycholate, an ionic detergent. Both the skeleton-associated Pr65('gag) and its NP40-soluble counterpart were labeled with {('3)H}-palmitate, indicating their probable association with lipids presumably in the plasma membrane. Pr65('gag) molecules bound to skeletal elements in the infected cell appeared to be more stable to proteolytic processing than NP40-soluble Pr65('gag). Our studies with certain ts mutants of murine leukemia virus, defective in virus assembly, including Mo-MuLV ts3 and R-MuLV ts17, ts24, ts25 and ts26, have shown that virions released at 39(DEGREES)C (nonpermissive temperature) had high levels of uncleaved Pr65('gag) relative to that seen in virions released at 33(DEGREES)C (permissive temperature). Examination of cell extracts revealed that Pr54('gag) was more stable to processing at 39(DEGREES)C than at 33(DEGREES)C, whereas the 'env' and glycosylated 'gag' proteins were processed to the same extent at both temperatures. Detergent extraction of pulse-labeled cells to generate an NP40-insoluble cytoskeleton-enriched fraction showed that in ts3-, ts17- and ts24-infected cells, Pr65('gag) accumulated in the cytoskeleton-enriched fraction. In contrast, cells infected with ts25 or ts26 showed no preferential localization of Pr65('gag) in the cytoskeleton in a short pulse, but instead, Pr65('gag) accumulated in both the NP40-soluble and -insoluble fractions during a chase-incubation. The association of Pr65('gag) with cytoskeletal elements in the cell was neither increased nor decreased by blocking virus assembly and release with interferon. Based on these and other results, we have proposed a model for the active role of cytoskeleton-associated Pr65('gag) in retrovirus assembly.^

STUDIES ON THE CLASS I GLYCOPROTEINS OF THE MURINE MAJOR HISTOCOMPATIBILITY COMPLEX (TRANSPLANTATION ANTIGEN, LYMPHOCYTE, CELL SURFACE MOLECULE)

A series of studies were undertaken to analyze and compare various aspects of murine class I glycoproteins. An initial area of investigation characterized the Qa-1 alloantigens using two-dimensional gel electrophoresis. Analysis of the products of the Qa-1('b), Qa-1('c) and Qa-1('d) alleles indicated that these were distinct molecules as determined by their lack of comigration upon comparative two-dimensional gel analysis. The importance of asparagine-linked glycosylation in the cell surface expression of class I molecules was also examined. These studies employed tunicamycin, an inhibitor of N-linked glycosylation. Tunicamycin treatment of activated T lymphocytes diminished the surface expression of Qa-1 to undetectable levels; the levels of other class I molecules exhibited little or no decrease. These results indicated that N-linked glycosylation has a differential importance in the cell surface expression of various class I molecules. The molecular weight diversity of class I molecules was also investigated. Molecular weight determination of both the fully glycosylated and unglycosylated forms of H-2 and Qa/Tla region encoded molecules established that there is a significant variation in the sizes of these forms of various class I molecules. The most significant difference ((TURN)9,000 daltons) exists between the unglycosylated forms of H-2K('b) and Qa-2, suggesting that the structural organization of these two molecules may be very different. A comparative two-dimensional gel analysis of various class I glycoproteins isolated from resting and activated T and B lymphocytes indicated that class I molecules expressed on activated T cells exhibited an isoelectrophoretic pattern that was distinct from the isoelectrophoretic pattern of class I molecules expessed on the other cell populations. This difference was attributed to a lower sialic acid content of the molecules expressed on activated T cells. Analysis of cell homogenates determined that activated T cells contained a higher level of endogenous neuraminidase activity than was detected in the other populations, suggesting that this may be the basis of the lower sialic acid content. The relationship of the Qa-4 and Qa-2 alloantigens was also examined. It was established that upon mitogen activation, the expression of Qa-4 was greatly decreased, whereas Qa-2 expression was not decreased. However, an anti-Qa-2 monoclonal antibody blocked the binding of an anti-Qa-4 monoclonal antibody to resting cells. These studies established that Qa-4 is a determinant restricted to resting cells, which is closely associated on the surface with the Qa-2 molecule. ^

The effectiveness of a promotora-led intervention for Mexican Americans with type 2 diabetes

Purpose. The purpose of this randomized control repeated measures trial was to determine the effectiveness of a self-management intervention led by community lay workers called promotoras on the health outcomes of Mexican Americans with type 2 diabetes living in a major city on the Texas - Mexico border. The specific aims of this study, in relation to the intervention group participants, were to: (1) decrease the glycosylated hemoglobin (A1c) blood levels at the six-month assessment, (2) increase diabetes knowledge at the three and six-month assessments, and (3) strengthen the participants' beliefs in their ability to manage diabetes at the three and six-month assessments.^ Methods. One hundred and fifty Mexican American participants were recruited at a Catholic faith-based clinic and randomized into an intervention group and a usual-care control group. Personal characteristics, acculturation and baseline A1c, diabetes knowledge and diabetes health beliefs were measured. The six-month, two-phase intervention was culturally specific and it was delivered entirely by promotoras. Phase One of the intervention consisted of sixteen hours of participative group education and bi-weekly telephone contact follow-up. Phase Two consisted of bi-weekly follow-up using inspirational faith-based health behavior change postcards. The A1c levels, diabetes knowledge and diabetes health beliefs were measured at baseline, and three and six months post-baseline. The mean changes between the groups were analyzed using analysis of covariance. ^ Results. The 80% female sample, with a mean age of 58 years, demonstrated very low: acculturation, income, education, health insurance coverage, and strong Catholicism. No significant changes were noted at the three-month assessment, but the mean change of the A1c levels (F (1, 148 = 10.28, p < .001) and the diabetes knowledge scores (F (1, 148 = 9.0, p < .002) of the intervention group improved significantly at six months, adjusting for health insurance coverage. The diabetes health belief scores decreased in both groups.^ Conclusions. This study demonstrated that an intervention led by promotoras could result in decreased A1c levels and increased diabetes knowledge in spite of the very low acculturation, educational level and insurance coverage of the intervention group participants. Clinical implications and recommendations for future research are suggested. ^

Diabetic nephropathy in African-Americans with type 1 diabetes: The new Jersey 725 study

Diabetic nephropathy is the most common cause of end-stage renal disease (ESRD) in the United States. African-Americans and patients with type 1 diabetes (T1D) are at increased risk. We studied the rate and factors that influenced progression of glomerular filtration rate (GFR) in 401 African-American T1D patients who were followed for 6 years through the observational cohort New Jersey 725 study. Patients with ESRD and/or GFR<20 ml/min were excluded. The mean (SD) baseline GFR was 106.8 (27.04) ml/min and it decreased by 13.8 (mean, SD 32.2) ml/min during the 6-year period (2.3 ml/min/year). In patients with baseline macroproteinuria, GFR decreased by 31.8 (39.0) ml/min (5.3 ml/min/year) compared to 8.2 (mean, SD 27.6) ml/min (1.3 ml/min/year) in patients without it (p<0.00001). Six-year GFR fell to <20 ml/min in 5.25% of all patients, but in 16.8% of macroproteinuric patients.^ A model including baseline GFR, proteinuria category and hypertension category, explained 35% of the 6-year GFR variability (p<0.0001). After adjustment for other variables in the model, 6-year GFR was 24.9 ml/min lower in macroproteinuric patients than in those without proteinuria (p=0.0001), and 12.6 ml/min lower in patients with treated but uncontrolled hypertension compared to normotensive patients (p=0.003). In this sample of patients, with an elevated mean glycosylated hemoglobin of 12.4%, glycemic control did not independently influence GFR deterioration, nor did BMI, cholesterol, gender, age at diabetes onset or socioeconomic level.^ Taken together, our findings suggest that proteinuria and hypertension are the most important factors associated with GFR deterioration in African-American T1D patients.^

Macular edema in Hispanics with non-insulin dependent diabetes mellitus in Starr County, Texas: Prevalence, incidence and risk factors

This project is based on secondary analyses of data collected in Starr County, Texas from 1981 till 1991 to determine the prevalence, incidence and risk factors for macular edema in Hispanics with non-insulin-dependent diabetes in Starr County, Texas. Two studies were conducted. The first study examined the prevalence of macular edema in this population. Of the 310 diabetics that were included in the study 22 had macular edema. Of these 22 individuals 9 had clinically significant macular edema. Fasting blood glucose was found to be significantly associated with macular edema. For each 10 mg/dl increase in fasting blood glucose there was a 1.07 probability of an increase in the risk of having macular edema. Individuals with fasting blood glucose $\ge$200 mg/dl were found to be more than three times at risk of having macular edema compared to those with fasting blood glucose $<$200 mg/dl.^ In the second study the incidence and the risk factors that could cause macular edema in this Hispanic population were examined. 240 Hispanics with non-insulin-dependent diabetes mellitus and without macular edema were followed for 1223 person-years. During the follow-up period 27 individuals developed macular edema (2.21/100 person-years). High fasting blood glucose and glycosylated hemoglobin were found to be strong and independent risk factors for macular edema. Participants taking insulin were 3.9 times more at risk of developing macular edema compared to those not taking insulin. Systolic blood pressure was significantly related to macular edema, where each 10 mmHg increase in systolic blood pressure was associated with a 1.3 increase in the risk of macular edema.^ In summary, this study suggests that hyperglycemia is the main underlying factor for retinal pathological changes in this diabetic population, and that macular edema probably is not the result of sudden change in the blood glucose level. It also determined that changes in blood pressure, particularly systolic blood pressure, could trigger the development of macular edema.^ Based on the prevalence reported in this study, it is estimated that 35,500 Hispanic diabetics in the US have macular edema. This imposes a major public health challenge particularly in areas with high concentration of Mexican Americans. It also highlights the importance of public health measures directed to Mexican Americans such as health education, improved access to medical care, and periodic and careful ophthalmologic examination by ophthalmologists knowledgeable and experienced in the management of diabetic macular edema. ^

A GENETIC MARKER STUDY OF NON - INSULIN DEPENDENT DIABETICS IN THE MEXICAN-AMERICAN COMMUNITY FROM STARR COUNTY, TEXAS (PLASMA GLUCOSE, HEMOGLOBIN ANALYSIS)

Diabetes mellitus occurs in two forms, insulin-dependent (IDDM, formerly called juvenile type) and non-insulin dependent (NIDDM, formerly called adult type). Prevalence figures from around the world for NIDDM, show that all societies and all races are affected; although uncommon in some populations (.4%), it is common (10%) or very common (40%) in others (Tables 1 and 2).^ In Mexican-Americans in particular, the prevalence rates (7-10%) are intermediate to those in Caucasians (1-2%) and Amerindians (35%). Information about the distribution of the disease and identification of high risk groups for developing glucose intolerance or its vascular manifestations by the study of genetic markers will help to clarify and solve some of the problems from the public health and the genetic point of view.^ This research was designed to examine two general areas in relation to NIDDM. The first aims to determine the prevalence of polymorphic genetic markers in two groups distinguished by the presence or absence of diabetes and to observe if there are any genetic marker-disease association (univariate analysis using two by two tables and logistic regression to study the individual and joint effects of the different variables). The second deals with the effect of genetic differences on the variation in fasting plasma glucose and percent glycosylated hemoglobin (HbAl) (analysis of Covariance for each marker, using age and sex as covariates).^ The results from the first analysis were not statistically significant at the corrected p value of 0.003 given the number of tests that were performed. From the analysis of covariance of all the markers studied, only Duffy and Phosphoglucomutase were statistically significant but poor predictors, given that the amount they explain in terms of variation in glycosylated hemoglobin is very small.^ Trying to determine the polygenic component of chronic disease is not an easy task. This study confirms the fact that a larger and random or representative sample is needed to be able to detect differences in the prevalence of a marker for association studies and in the genetic contribution to the variation in glucose and glycosylated hemoglobin. The importance that ethnic homogeneity in the groups studied and standardization in the methodology will have on the results has been stressed. ^

DIABETIC RETINOPATHY IN NON-INSULIN-DEPENDENT DIABETES MELLITUS IN BLACK WOMEN: A DESCRIPTIVE STUDY OF RISK FACTORS

This cross-sectional study examines the prevalence of selected potential risk factors by stage of diabetic retinopathy (DR) among Black American women with non-insulin-dependent diabetes mellitus (NIDDM) followed at a university diabetes clinic. DR was assessed by ophthalmoscopy and five-field retinography, and graded on counts of microaneurysms, hemorrhages and/or exudates, and presence of proliferative DR. Prevalence of other vascular diseases was assessed from medical records. Potential risk factors included age, known duration of diabetes, type of hypoglycemic treatment, concentrations of random capillary blood glucose, glycosylated hemoglobin, urine protein and fibrinogen, body mass index, and blood pressure. Prevalence of these risk factors is reported for three categories: No DR, mild background DR, severe background or proliferative DR (including surgically treated DR). Duration, age at diagnosis and treatment of diabetes, concentration of urine protein and average blood glucose, hypertension and cardiovascular disease were significantly associated with DR in univariate analysis. The covariance analysis employed stratification on duration, age at diagnosis and therapy of diabetes. The highest DR scores were calculated for those diagnosed before age 45, regardless of duration, therapy, or average blood glucose. Only individuals diagnosed before age 45 had high blood glucose concentrations in all categories of duration. These findings suggest that in this clinic population of Black women, those diagnosed with NIDDm before age 45 who eventually required insulin treatment were at the greatest risk of developing DR and that longterm poor glucose control is a contributing factor. These results suggest that greater emphasis be placed on this subgroup in allocating the limited resources available to improve the quality of glucose regulation, particularly through measures affecting compliance behavior.^ Findings concerning the association of DR with concentration of blood glucose and urine protein, blood pressure/hypertension and weight were compared with those reported from American Indian and Mexican American populations of the Southwestern United States where prevalence of NIDDM, hypertension and obesity is also high. Additional comparative analyses are outlined to substantiate the preliminary finding that there are systematic differences between these ethnic populations. ^

Compromised disease resistance in saponin-deficient plants

Saponins are glycosylated plant secondary metabolites found in many major food crops [Price, K. R., Johnson, I. T. & Fenwick, G. R. (1987) CRC Crit. Rev. Food Sci. Nutr. 26, 27–133]. Because many saponins have potent antifungal properties and are present in healthy plants in high concentrations, these molecules may act as preformed chemical barriers to fungal attack. The isolation of plant mutants defective in saponin biosynthesis represents a powerful strategy for evaluating the importance of these compounds in plant defense. The oat root saponin avenacin A-1 fluoresces under ultraviolet illumination [Crombie, L., Crombie, W. M. L. & Whiting, D. A. (1986) J. Chem. Soc. Perkins 1, 1917–1922], a property that is extremely rare among saponins. Here we have exploited this fluorescence to isolate saponin-deficient (sad) mutants of a diploid oat species, Avena strigosa. These sad mutants are compromised in their resistance to a variety of fungal pathogens, and a number of lines of evidence suggest that this compromised disease resistance is a direct consequence of saponin deficiency. Because saponins are widespread throughout the plant kingdom, this group of secondary metabolites may have general significance as antimicrobial phytoprotectants.

The crystal structure of human interferon β at 2.2-Å resolution

Type I interferons (IFNs) are helical cytokines that have diverse biological activities despite the fact that they appear to interact with the same receptor system. To achieve a better understanding of the structural basis for the different activities of α and β IFNs, we have determined the crystal structure of glycosylated human IFN-β at 2.2-Å resolution by molecular replacement. The molecule adopts a fold similar to that of the previously determined structures of murine IFN-β and human IFN-α2b but displays several distinct structural features. Like human IFN-α2b, human IFN-β contains a zinc-binding site at the interface of the two molecules in the asymmetric unit, raising the question of functional relevance for IFN-β dimers. However, unlike the human IFN-α2b dimer, in which homologous surfaces form the interface, human IFN-β dimerizes with contact surfaces from opposite sides of the molecule. The relevance of the structure to the effects of point mutations in IFN-β at specific exposed residues is discussed. A potential role of ligand–ligand interactions in the conformational assembly of IFN receptor components is discussed.

Design of compounds that increase the absorption of polar molecules

Hydrophilic drugs are often poorly absorbed when administered orally. There has been considerable interest in the possibility of using absorption enhancers to promote absorption of polar molecules across membrane surfaces. The bile acids are one of the most widely investigated classes of absorption enhancers, but there is disagreement about what features of bile acid enhancers are responsible for their efficacy. We have designed a class of glycosylated bile acid derivatives to evaluate how increasing the hydrophilicity of the steroid nucleus affects the ability to transport polar molecules across membranes. Some of the glycosylated molecules are significantly more effective than taurocholate in promoting the intestinal absorption of a range of drugs, showing that hydrophobicity is not a critical parameter in transport efficacy, as previously suggested. Furthermore, the most effective glycosylated compound is also far less damaging to membranes than the best bile acid absorption promoters, presumably because it is more hydrophilic. The results reported here show that it is possible to decouple absorption-promoting activity from membrane damage, a finding that should spark interest in the design of new compounds to facilitate the delivery of polar drugs.

Influenza C virus CM2 integral membrane glycoprotein is produced from a polypeptide precursor by cleavage of an internal signal sequence

The influenza C virus CM2 protein is a small glycosylated integral membrane protein (115 residues) that spans the membrane once and contains a cleavable signal sequence at its N terminus. The coding region for CM2 (CM2 ORF) is located at the C terminus of the 342-amino acid (aa) ORF of a colinear mRNA transcript derived from influenza C virus RNA segment 6. Splicing of the colinear transcript introduces a translational stop codon into the ORF and the spliced mRNA encodes the viral matrix protein (CM1) (242 aa). The mechanism of CM2 translation was investigated by using in vitro and in vivo translation of RNA transcripts. It was found that the colinear mRNA derived from influenza C virus RNA segment 6 serves as the mRNA for CM2. Furthermore, CM2 translation does not depend on any of the three in-frame methionine residues located at the beginning of CM2 ORF. Rather, CM2 is a proteolytic cleavage product of the p42 protein product encoded by the colinear mRNA: a cleavage event that involves the recognition and cleavage of an internal signal peptide presumably by signal peptidase resident in the endoplasmic reticulum. Alteration of the predicted signal peptidase cleavage site by mutagenesis blocked generation of CM2. The other polypeptide species resulting from the cleavage of p42, designated p31, contains the CM1 coding region and an additional C-terminal 17 aa (formerly the CM2 signal peptide). Protein p31, in comparison to CM1, displays characteristics of an integral membrane protein.

Glycosylation differences between the normal and pathogenic prion protein isoforms

Prion protein consists of an ensemble of glycosylated variants or glycoforms. The enzymes that direct oligosaccharide processing, and hence control the glycan profile for any given glycoprotein, are often exquisitely sensitive to other events taking place within the cell in which the glycoprotein is expressed. Alterations in the populations of sugars attached to proteins can reflect changes caused, for example, by developmental processes or by disease. Here we report that normal (PrPC) and pathogenic (PrPSc) prion proteins (PrP) from Syrian hamsters contain the same set of at least 52 bi-, tri-, and tetraantennary N-linked oligosaccharides, although the relative proportions of individual glycans differ. This conservation of structure suggests that the conversion of PrPC into PrPSc is not confined to a subset of PrPs that contain specific sugars. Compared with PrPC, PrPSc contains decreased levels of glycans with bisecting GlcNAc residues and increased levels of tri- and tetraantennary sugars. This change is consistent with a decrease in the activity of N-acetylglucosaminyltransferase III (GnTIII) toward PrPC in cells where PrPSc is formed and argues that, in at least some cells forming PrPSc, the glycosylation machinery has been perturbed. The reduction in GnTIII activity is intriguing both with respect to the pathogenesis of the prion disease and the replication pathway for prions.