Plasma Biomarkers of AD Emerging as Essential Tools for Drug Development: An EU/US CTAD Task Force Report.

There is an urgent need to develop reliable and sensitive blood-based biomarkers of Alzheimer's disease (AD) that can be used for screening and to increase the efficiency of clinical trials. The European Union-North American Clinical Trials in Alzheimer's Disease Task Force (EU/US CTAD Task Force) discussed the current status of blood-based AD biomarker development at its 2018 annual meeting in Barcelona, Spain. Recent improvements in technologies to assess plasma levels of amyloid beta indicate that a single sample of blood could provide an accurate estimate of brain amyloid positivity. Plasma neurofilament light protein appears to provide a good marker of neurodegeneration, although not specific for AD. Plasma tau shows some promising results but weak or no correlation with CSF tau levels, which may reflect rapid clearance of tau in the bloodstream. Blood samples analyzed using -omics and other approaches are also in development and may provide important insight into disease mechanisms as well as biomarker profiles for disease prediction. To advance these technologies, international multidisciplinary, multi-stakeholder collaboration is essential.

Prophylaxis of recurrent urinary tract infection after renal transplantation by cranberry juice and L-methionine.

BACKGROUND: Recurrent urinary tract infections (UTIs) increase mortality and reduce graft survival after renal transplantation. Strategies to prevent recurrent UTIs include L-methionine, cranberry juice, and antibiotics. Data on the efficacy of cranberry and L-methionine, however, are controversial in the general population; there are few data in renal transplant recipients. METHODS: We performed a retrospective analysis of 82 transplant recipients with recurrent UTIs, who underwent prophylaxis with cranberry juice (2 × 50 mL/d, n = 39, 47.6%), or L-methionine (3 × 500 mg/d, n = 25, 30.5%), or both modalities (n = 18, 21.9%). Thirty patients without prophylaxis served as controls. We analyzed symptoms, pyuria/nitrituria, and incidence of UTI events during 1 year before versus after initiation of prophylaxis. RESULTS: Prophylaxis highly significantly decreased the annual UTI incidence by 58.3% (P < .001) in the study population with no change in the control group (P = .85); in addition, 53.7% of symptomatic patients reported relief of symptoms and pyuria/nitrituria disappeared in 42.4% of the dipstick-positive patients (P < .001 each). Cranberry reduced the annual number of UTI episodes by 63.9% from 3.6 ± 1.4 to 1.3 ± 1.3/year (P < .001) and L-methionine by 48.7% from 3.9 ± 1.8 to 2.0 ± 1.3/year (P < .001). CONCLUSION: Cranberry juice and L-methionine successfully reduced the incidence of UTI after renal transplantation.

Effects of the Tibetan herbal preparation PADMA 28 on blood lipids and lipid oxidisability in subjects with mild hypercholesterolaemia.

BACKGROUND: Previous studies showed an anti-atherosclerotic effect of PADMA 28, an herbal formula based on Tibetan medicine. As the mechanisms of action are not fully understood, we investigated whether PADMA 28 may lower blood lipids and lipid oxidisability, and affect early endothelial dysfunction. PATIENTS AND METHODS: Sixty otherwise healthy subjects with total cholesterol > or = 5.2 mmol/l and < 8.0 mmol/l were randomly assigned to placebo or PADMA 28, 3 x 2 capsules daily, for 4 weeks (double-blind). Blood lipids (total, LDL-, and HDL-cholesterol, triglycerides, Apo-lipoprotein A1 and B) and ex vivo lipid oxidisability were measured before and after treatment. In a subset of 24 subjects, endothelial function was assessed using venous occlusion plethysmography with intraarterial infusion of acetylcholine. Isolated LDL and plasma both untreated and pre-treated with PADMA 28 extract were oxidised by the radical generator AAPH. Conjugated diene formation was measured at 245 nm. RESULTS: Blood lipids did not change during the study in both groups. In contrast to previous reports in mild hypercholesterolaemia, no endothelial dysfunction was seen and, consequently, was not influenced by therapy. Ex vivo blood lipid oxidisability was significantly reduced with PADMA 28 (area undercurve: 5.29 +/- 1.62 to 4.99 +/- 1.46, p = 0.01), and remained unchanged in the placebo group (5.33 +/- 1.88 to 5.18 +/- 1.78, p > 0. 1). This effect persisted one week after cessation of medication. In vitro experiments confirmed the prevention of lipid peroxidation in the presence of PADMA 28 extracts. Persistent protection was also seen for LDL isolated from PADMA 28-pretreated blood after being subjected to rigorous purification. CONCLUSIONS: This study suggests that the inhibition of blood lipid oxidisability by PADMA 28 may play a role in its anti-atherosclerotic effect.

Type 1 aldosterone synthase deficiency presenting in a middle-aged man.

Aldosterone synthase deficiency due to mutations in the CYP11B2 gene usually presents in infancy with electrolyte abnormalities and failure to thrive, whereas affected adults are usually asymptomatic. We describe a patient who first came to medical attention in middle age when he developed hyperkalemia after preparation for a barium enema. Past medical history was notable for failure to thrive in infancy. He had elevated PRA with low serum and urinary levels of aldosterone and its metabolites and normal or slightly elevated levels of 18-hydroxycorticosterone. These findings suggested a diagnosis of type 1 aldosterone synthase deficiency. The patient had a homozygous duplication of six nucleotides at codon 143 in exon 3 of CYP11B2, leading to the insertion of two amino acid residues (Arg-Leu). When the corresponding mutant complementary DNA was expressed in cultured cells, the resulting enzyme was completely inactive, confirming the diagnosis. We conclude that aldosterone synthase deficiency represents an unusual cause of hyperreninemic hypoaldosteronism presenting in adult life, but it should be suspected if the past medical history is positive for failure to thrive in childhood or if the patient manifests no other recognized causes of hyperreninemic hypoaldosteronism.

Peritonitis associated with vancomycin-resistant Lactobacillus rhamnosus in a continuous ambulatory peritoneal dialysis patient: organism identification, antibiotic therapy, and case report.

A case of Lactobacillus rhamnosus-associated peritonitis in a patient undergoing continuous ambulatory peritoneal dialysis is reported. The patient was treated with vancomycin after isolation of glycopeptide-susceptible coagulase-negative staphylococci. After a skin rash developed, vancomycin was discontinued and replaced with teicoplanin. Seven weeks after the glycopeptide therapy was discontinued, a Lactobacillus strain was isolated in pure cultures. The isolate was identified first incorrectly as L. acidophilus but later correctly as L. rhamnosus. Antibiotic susceptibility testing showed that the isolate was resistant to glycopeptides but susceptible to several other antibiotics. The antibiotic treatment was then switched to imipenem and was successful.

The role of magnesium in the generation and therapy of benign muscle cramps. Combined in-vivo/in-vitro studies on rat phrenic nerve-diaphragm preparations.

Rats received during 3 weeks a Mg-deficient or a Mg-rich diet; Mg-deficient animals revealed hypomagnesemia, cellular K-depletion and Ca-loading. Phrenic nerve-diaphragm preparations were studied; the physiological Tyrode solution contained low or high-Mg concentrations and 0 or 12 mmol lactate/L. Electric stimulation (indirect via the nerve or direct) produced tetanic contractions and increased force at increasing stimulation frequencies. Significantly lower frequencies were needed to elicit these effects when intra- and extracellular Mg levels were low, in comparison to plentiful Mg supply. Comparing unstimulated and stimulated diaphragmatic tissue electrolyte concentrations revealed tissue losses of Mg, K Ca from stimulated tissues which were less pronounced when Mg supply was optimal. These data support the empiric finding that relief from muscle cramps is promptly offered by Mg supplements.

Phosphorus magnetic resonance spectroscopy in the evaluation of mitochondrial myopathies: results of a 6-month therapy study with coenzyme Q.

31P magnetic resonance spectroscopy (MRS) was used to study an open therapeutic trial of coenzyme Q10 (CoQ) in mitochondrial encephalomyopathies. Eight patients were treated with 150 mg CoQ per day for 6 months. 31P MRS spectra of calf muscle were recorded at rest, during exercise and in the immediate postexercise recovery period. Although there was an improvement of the mean ratio of phosphocreatine (PCr) to inorganic phosphate during the post-exercise recovery period after 3 months of treatment, this finding was mainly due to a single therapy responder and did not reflect a beneficial effect on the whole group. Improved repletion of PCr persisted after 6 months of therapy. Our study identified a single responder to this therapy, whose response could not be predicted on the basis of clinical, biochemical or molecular data. These findings suggest that therapeutic trials of CoQ should be performed under close metabolic monitoring in order both to identify responders for subsequent long-term treatment and to evaluate possible mechanisms of this supportive therapy.

A dual role for COOH-terminal lysine residues in pre-Golgi retention and endocytosis of ERGIC-53.

ERGIC-53 (former designation, p53) is a 53-kDa nonglycosylated, dimeric, and hexameric type I membrane protein that has been established as a marker protein for a tubulovesicular intermediate compartment in which protein transport from the endoplasmic reticulum to the Golgi apparatus is blocked at 15 degrees C. Although ERGIC-53 is not a resident protein of the rough endoplasmic reticulum its cDNA sequence carries a double lysine endoplasmic reticulum retention motif at the cytoplasmically exposed COOH terminus. Here we report that overexpression of ERGIC-53 in COS cells saturates its intracellular retention system leading to the appearance of ERGIC-53 at the cell surface. Cell surface ERGIC-53 is efficiently endocytosed by a mechanism that is disturbed when the two critical lysines of the endoplasmic reticulum retention motif are replaced by serines. The results suggest a mechanistic similarity of pre-Golgi retention by the double lysine motif and lysine-based endocytosis.

Dietary supplementation with n-3 fatty acids suppresses interleukin-2 production and mononuclear cell proliferation.

We studied the in vitro production of interleukin-2 in nine healthy volunteers who added 18 g/day of fish-oil concentrate rich in n-3 polyunsaturated fatty acids to their normal Western diet for a period of 6 weeks. Interleukin-2 synthesis from stimulated peripheral blood mononuclear cells was suppressed from 6.2 ng/ml at baseline to 2.2 ng/ml 10 weeks after the end of n-3 fatty acid supplementation (65% decrease; P = .04). At the same time phytohemagglutinin-induced proliferation of mononuclear cells was suppressed by 70% from the presupplement level. Interleukin-2 production returned to the premedication level at the end of the studies. The results suggest that the effect of dietary n-3 fatty acids in some diseases may be mediated in part by decreased production of interleukin-2 and decreased mononuclear cell proliferation.

ERGIC-53, a membrane protein of the ER-Golgi intermediate compartment, carries an ER retention motif.

Overlapping cDNAs encoding the entire human ERGIC-53, a 53 kDa membrane protein of the ER-Golgi intermediate compartment, have been isolated and their nucleotide sequence determined. The isolated cDNA is about 2.7 kb in length. The deduced polypeptide chain for ERGIC-53 consists of 510 amino acids (M(r) 54217) including an N-terminal signal sequence of 30 amino acids, a single putative transmembrane segment of 18 amino acids, and a short cytoplasmic domain of 12 amino acids. Surprisingly, the cytoplasmic segment contains two lysines positioned three and four residues from the C-terminus. Such a double lysine motif is known to function as a retention signal for a group of membrane proteins associated with the ER. Expression of a full-length cDNA of ERGIC-53 in Vero cells revealed intracellular localization similar but not always identical to the endogenously expressed ERGIC-53. The presence of an ER retention motif in a protein of the ER-Golgi intermediate compartment has important implications for the retention mechanism mediated by this signal.

31P magnetic resonance spectroscopy in dilated cardiomyopathy and coronary artery disease. Altered cardiac high-energy phosphate metabolism in heart failure.

BACKGROUND: The purpose of this work was to further define the value of cardiac 31P magnetic resonance (MR) spectroscopy for patients with coronary artery disease and dilated cardiomyopathy. METHODS AND RESULTS: Blood-corrected and T1-corrected 31P MR spectra of anteroseptal myocardium were obtained at rest using image-selected in vivo spectroscopy localization, a selected volume of 85 +/- 12 cm3, and a field strength of 1.5 T. Nineteen volunteers had a creatine phosphate (CP)/ATP ratio of 1.95 +/- 0.45 (mean +/- SD) and a PDE/ATP ratio of 1.06 +/- 0.53; in four patients with left anterior descending coronary artery (LAD) stenosis, six patients with chronic anterior wall infarction, and four patients with chronic posterior wall infarction, CP/ATP and phosphodiester (PDE)/ATP ratios did not differ from those in volunteers. Twenty-five measurements of 19 patients with dilated cardiomyopathy yielded a CP/ATP of 1.78 +/- 0.51 and a PDE/ATP of 0.98 +/- 0.56 (p = NS versus volunteers). When these patients were grouped according to the severity of heart failure, however, CP/ATP was 1.94 +/- 0.43 in mild (p = NS versus volunteers) and 1.44 +/- 0.52 in severe DCM (p < 0.05), respectively. No correlation was found between CP/ATP and left ventricular ejection fraction or fractional shortening, but correlation of CP/ATP with the New York Heart Association (NYHA) class was significant (r = 0.60, p < 0.005). Six patients with dilated cardiomyopathy were studied repeatedly before and after 12 +/- 6 weeks of drug treatment leading to clinical recompensation with improvement of the NYHA status by 0.8 +/- 0.3 classes. Concomitantly, CP/ATP increased from 1.51 +/- 0.32 to 2.15 +/- 0.27 (p < 0.01), whereas PDE/ATP did not change significantly. CONCLUSIONS: Cardiac high-energy phosphate metabolism at rest is normal in LAD stenosis and chronic myocardial infarction in the absence of heart failure. The CP/ATP ratio has low specificity for the diagnosis of dilated cardiomyopathy. However, CP/ATP correlated with the clinical severity of heart failure and may improve during clinical recompensation.

[The direct measurement of the spin-grid-relaxation times of phosphorus metabolites in the human myocardium]. / Direkte Messung der Spin-Gitter-Relaxationszeiten von Phosphormetaboliten im menschlichen Myokard.

The T1 relaxation times of the phosphorus metabolites in human heart muscle measurable by 31P-MR spectra were determined in 12 individuals using a 1.5 Tesla system. Several spectra were recorded consecutively with a pulse repetition time of 1.6 s to 24 s. The T1 times of creatine phosphate (CP), of gamma-, alpha-, beta-adenosintriphosphate (ATP), 2,3-diphosphoglycerate (2,3-DPG) together with anorganic phosphate) and phosphodiester (PDE) showed mean measurements of 6.1 +/- 0.5, 5.4 +/- 0.5, 5.0 +/- 0.5, 5.8 +/- 1.0, 7.6 +/- 1.0, and 5.0 +/- 1.0 s (M +/- SE). The accuracy of the ISIS technique was tested with a special phantom. T1 times were also measured in standard solutions (20 mM CP, 10 mM ATP); CP was 8.7 +/- 0.2 s and gamma-ATP was 9.9 +/- 0.7 s. Corrections for partially saturated 31P-MR spectra--at least for CP/ATP ratios--are relatively small.

Direct measurement of spin-lattice relaxation times of phosphorus metabolites in human myocardium.

T1 values of phosphorus metabolites visible in human cardiac 31P-MR spectra were determined in 12 volunteers at 1.5 T. Consecutive spectra were acquired with varying pulse repetition time (TR) from 1.6 to 24 s; volume selection was achieved with ISIS. T1's of creatine phosphate (CP), [gamma-P], [alpha-P], and [beta-P]ATP, 2-3 diphosphoglycerate, and phosphodiesters were 6.1 +/- 0.5, 5.4 +/- 0.5, 5.5 +/- 0.5, 5.8 +/- 1.0, 7.6 +/- 1.0, and 5.0 +/- 1.0 s, respectively. CP/ATP ratios showed little change with varying TR; linear regression of CP/ATP vs TR was of borderline significance (r = 0.28, P = 0.06). T1's for CP and ATP were also determined in standard solution (20 mM CP, 10 mM ATP) yielding T1CP of 8.7 +/- 0.2 and T1[gamma-P]-ATP of 9.9 +/- 0.7 s. Thus, T1's for CP and ATP were similar at 1.5 T in both human heart and standard solution. In human cardiac 31P-MR spectra, CP/ATP ratios may need little correction for partial saturation.

Stapedectomy in residency training.

The number of new patients with otosclerosis seen by the average otolaryngologist has declined over the past several years. As a result, a controversy has arisen regarding the ability to train residents adequately in the technique of stapedectomy. In this regard, we have analyzed 44 consecutive stapedectomies performed by senior residents, under direct faculty supervision, at the University of California, San Francisco. All procedures were total stapedectomies, performed under local anesthesia, utilizing either wire-vein or wire-perichondrium technique. Four of the ears required footplate or promontory drilling. Closure to within 10 dB of the preoperative bone conduction, averaged over the speech frequencies of 500, 1000, and 2000 Hz, was achieved in 75% of ears, and closure to within 20 dB in 93% of ears. In no patient was hearing made worse. While there were no permanent complications, self-limited problems occurred in 9% of the procedures. Despite a declining caseload of otosclerotic ears in residency programs, it is possible to train residents safely in stapes surgery, given a program of consistent technique and close faculty supervision.

Vitamin E and retrolental fibroplasia: prevention of serious ocular sequelae.

In an attempt to determine the role of vitamin E in retrolental fibroplasia (RLF) we report our experience with 191 infants of less than 1500 g birth weight. Of these infants, 16.75% had evidence of acute RLF in hospital, 8.4% had cicatricial RLF at follow-up, and four infants (2.1%) were blind, none of whom had received supplementary vitamin E. The incidence of cicatricial RLF at follow-up was significantly lower in infants who received vitamin E early after birth (12 h) than in those who did not (3 of 105 versus 13 of 86, X2 = 9.26, P = 0.002), as was the incidence of Grade III or greater cicatrix (0 of 105 versus 7 of 86, X2 with Yates = 6.72, P = 0.01). Stepwise multiple linear regression analysis revealed three factors distinguishing infants who developed cicatricial RLF from those who did not: the lack of early vitamin E supplements (P = 0.0023), the significantly larger number of arterial PO2 values over 100 mmHg (P = 0.0056), and the presence of an intraventricular haemorrhage (P = 0.0032). The incidence and severity of necrotizing enterocolitis was similar in infants who received vitamin E and in those who did not. It is recommended that vitamin E be given within the first 12 hours of birth to all infants of less than 1500 g who require supplementary oxygen.

Effect of intramuscular vitamin E on frequency and severity of retrolental fibroplasia. A controlled trial.

126 appropriate-for-gestational age neonates born in hospital with birth-weights of 750 g-1500 g were prospectively studied in a randomised trial to determine the effect of intramuscular vitamin E on the frequency and severity of retrolental fibroplasia (RLF). In the 99 who lived for more than one month the frequency of active RLF in the vitamin E and control groups in the nursery (18.8% vs 23.5%) and at discharge (8.3% vs 19.6% was not significantly different. Vitamin E had significantly reduced the severity of RLF at follow-up eye examination 6-33 months after discharge (p less than 0.01). 3 control infants (760 g, 780 g, 1020 g) were blind in both eyes (grade V cicatricial RLF), whereas the most severe grade of disease in the vitamin E infants was grade II cicatrix. Infants in whom RLF developed were gestationally younger (p = 0.005), required a longer period of mechanical ventilation (p = 0.035), had a greater exposure to oxygen (p = 0.03), and had a greater number of arterial PO2 values between 75 and 99 mm Hg (p = 0.004). Early administration of vitamin E, while not affecting the frequency of RLF, will significantly reduce its severity and subsequent eye damage, and such treatment is recommended for all low-birth-weight infants of less than 1250 g who require supplementary oxygen.

Precursor-product relationships between thymidine nucleotides and DNA in mammalian cells. II. Studies with dTDP and dTTP on cells partially lysed by Brij-58.

Cells from Chinese hamster ovary cell cultures were partially lysed with Brij-58 and incubated in a reaction mixture containing deoxyribonucleoside triphosphates and permitting semiconservative DNA replication. The reaction mixture was supplemented with [3H]dTTP and [14C]dTDP or, alternatively, with [14C]dTTP and [3H]dTDP, and at different times, 3H and 14C specific activities of dTTP and dTDP, as well as 3H/14C ratios in DNA were determined. Isotope ratios in DNA were in good agreement with those expected if dTTP but not dTDP was used as the proximate precursor for DNA synthesis. These data support the conclusion that the thymidine nucleotide used as proximate substrate for DNA replication is dTTP.