Creutzfeldt--Jakob Disease in Recipients of Human Growth Hormone in the United Kingdom: A Clinical and Radiographic Study

In the past 3 years there have been five further cases, in additionto one case reported in 1985, of Creutzfeldt-Jakob disease inrecipients of human growth hormone in the United Kingdom. Theclinical findings of two of these cases are described, demonstratinga typical presentation with a predominantly cerebellar syndromeat onset which is not commonly a presenting feature of sporadicCreutzfeldt-Jakob disease. In one case a ^99mTc hexamethylpropylenaminesingle photon emission tomographic scan showed marked impairmentof tracer uptake in the basal ganglia and cerebral cortex ata time when the clinical picture was predominantly cerebellar.This technique may be useful in early diagnosis. In the othercase post mortem examination of the brain showed prominent amyloiddeposition in the cerebellum, which has not been described previouslyin pituitary-hormone related Creutzfeldt-Jakob disease. Thepreviously published cases of growth hormone-related Creutzfeldt-Jakobdisease are reviewed and reasons for the particular clinicalpattern seen are discussed.     

Outcome reliability in non‐Ambulatory Boys/Men with duchenne muscular dystrophy

Introduction: Therapeutic trials in Duchenne muscular dystrophy (DMD) often exclude non‐ambulatory individuals. Here we establish optimal and reliable assessments in a multicenter trial. Methods: Non‐ambulatory boys/men with DMD (N = 91; 16.7 ± 4.5 years of age) were assessed by trained clinical evaluators. Feasibility (percentage completing task) and reliability [intraclass correlation coefficients (ICCs) between morning and afternoon tests] were measured. Results: Forced vital capacity (FVC), assessed in all subjects, showed a mean of 47.8 ± 22% predicted (ICC 0.98). Brooke Upper Extremity Functional Rating (Brooke) and Egen Klassifikation (EK) scales in 100% of subjects showed ICCs ranging from 0.93 to 0.99. Manual muscle testing, range of motion, 9‐hole peg test, and Jebsen‐Taylor Hand Function Test (JHFT) demonstrated varied feasibility (99% to 70%), with ICCs ranging from 0.99 to 0.64. We found beneficial effects of different forms of corticosteroids for the Brooke scale, percent predicted FVC, and hand and finger strength. Conclusions: Reliable assessment of non‐ambulatory boys/men with DMD is possible. Clinical trials will have to consider corticosteroid use. Muscle Nerve 51: 522–532, 2015     

FcR gamma-chain is essential for both surface expression and function of human Fc gamma RI (CD64) in vivo

Most Ig receptors exist as hetero-oligomeric complexes with separate ligand binding (alpha) and signal transducing (beta, gamma, or zeta) subunits. For Fc gamma RIIIa and Fc epsilon RI, association with the FcR gamma-chain is essential for surface expression. However, the human high affinity IgG receptor, hFc gamma RI, was found to be surface- expressed by itself in transient transfection models. We have now analyzed the integrity of hFc gamma RI expression in more detail in stable transfectants. In vitro we noted that, in the absence of FcR gamma-chain, surface expression of hFc gamma RI rapidly declined to background levels, in both IIA1.6 B cells and NIH3T3 fibroblasts. The effect of FcR gamma-chain on hFc gamma RI surface expression in vivo was evaluated by using two newly generated transgenic mouse lines, selectively expressing hFc gamma RI on myeloid cells. These transgenic mice were crossed with FcR gamma-chain-deficient mice. Analysis of blood monocytes and peritoneal macrophages showed that surface expression of hFc gamma RI was reduced by approximately 80%. The remaining approximately 20% of receptors were still capable of binding IgG-opsonized RBC, suggesting FcR gamma-chain not to be critical for hFc gamma RI ligand-binding capacity. Importantly, however, hFc gamma RI signaling capacity was lost in FcR gamma-chain-deficient cells. No phagocytosis could be observed using either ligand sensitized (EA- IgG2a) or CD64-targeted erythrocytes (using a bispecific antibody) in both hFc gamma RI transgenic lines. This documents the FcR gamma-chain to be indispensable for both surface membrane expression and function of human Fc gamma RI in vivo.     

Potential therapeutic target for malignant paragangliomas: ATP synthase on the surface of paraganglioma cells

F1FoATP synthase (ATP synthase) is a ubiquitous enzyme complex in eukaryotes. In general it is localized to the mitochondrial inner membrane and serves as the last step in the mitochondrial oxidative phosphorylation of ADP to ATP, utilizing a proton gradient across the inner mitochondrial membrane built by the complexes of the electron transfer chain. However some cell types, including tumors, carry ATP synthase on the cell surface. It was suggested that cell surface ATP synthase helps tumor cells thriving on glycolysis to survive their high acid generation. Angiostatin, aurovertin, resveratrol, and antibodies against the α and β subunits of ATP synthase were shown to bind and selectively inhibit cell surface ATP synthase, promoting tumor cell death. Here we show that ATP synthase β (ATP5B) is present on the cell surface of mouse pheochromocytoma cells as well as tumor cells of human SDHB-derived paragangliomas (PGLs), while being virtually absent on chromaffin primary cells from bovine adrenal medulla by confocal microscopy. The cell surface location of ATP5B was verified in the tissue of an SDHB-derived PGL by immunoelectron microscopy. Treatment of mouse pheochromocytoma cells with resveratrol as well as ATP5B antibody led to statistically significant proliferation inhibition. Our data suggest that PGLs carry ATP synthase on their surface that promotes cell survival or proliferation. Thus, cell surface ATP synthase may present a novel therapeutic target in treating metastatic or inoperable PGLs.     

Augmentation of protein degradation by L-triiodothyronine in uremia

To ascertain if excessive protein catabolism is a feature of uremia, we determined leucine flux and nitrogen balance in 11 stable chronic dialysis patients and in 7 normal subjects. Leucine flux was determined during primed constant infusion of 2H3 and 15N leucine. Nitrogen balance was determined by measurement of nitrogen in the food, dialysate, and urine, and in the dialysis patients by correcting for the changing urea nitrogen pool. To assess if thyroid hormone adversely affects protein metabolism, the above-mentioned studies were done once in the basal state and once after a 7-day course of L-triiodothyronine (T3) treatment. Leucine carbon flux (mumol/kg/min) was 1.22 +/- 0.05 in the controls and 1.40 +/- 0.09 in the renal patients in the basal state (P = NS). Following T3 treatment, leucine carbon flux was increased to 1.40 +/- 0.05 and 1.72 +/- 0.09, respectively, in the controls and the renal patients (P less than .05). Fractional increment of the leucine carbon flux was 14% +/- 3% in the controls and 23% +/- 9% in the renal patients (P less than .05). The leucine nitrogen flux (mumol/kg/min) was 2.10 +/- 0.15 in the controls and 2.54 +/- 0.23 in the renal patients in the basal state (P = NS), and increased to 2.48 +/- 0.14 and 3.44 +/- 0.22, respectively, in controls and renal patients after T3 administration (P less than .05). Fractional increment of leucine nitrogen flux was 19.5% +/- 4.3% in the controls and 36.4% +/- 5.0% in the renal patients (P less than .05).(ABSTRACT TRUNCATED AT 250 WORDS)     

Laboratory testing for infection with the human immunodeficiency virus: established and novel approaches

The enzyme-linked immunosorbent assay (ELISA) and the Western blot are the primary tests for the diagnosis and confirmation of human immunodeficiency virus (HIV) infection. The ELISA, an inexpensive screening test for antibodies to HIV-1, is both sensitive and specific. The HIV-1 Western blot is a reliable confirmatory test following a repeatedly reactive ELISA. False-positive HIV-1 results with this sequence of tests are extremely rare but can occur, and test results that are inconsistent with clinical or other laboratory information should be questioned, repeated, or supplemented. The US Food and Drug Administration has also approved rapid and more accessible testing methods. Oral mucosal transudate and urine testing are noninvasive testing methods; rapid and home sample collection kits offer easier access to testing.