High power high voltage bias-T for half wave resonators and radio frequency quadrupole couplers

High power high voltage bias-T units capable of delivering up to 100 kW CW RF power at 176 MHz and up to 4 kV DC were developed at the Soreq Nuclear Research Center for the Soreq Applied Research Accelerator Facility linac. Two separate bias-T units with different requirements were designed for the radio frequency quadrupole couplers and the half wave resonator couplers. The purpose of this bias-T is to prevent multipacting phenomena by application of a high voltage DC bias to inner conductors of RF couplers. Underlying design principles, indigenous development, and successful off-line and on-line tests results are presented.

[AUTOPHAGY AND DIABETIC NEPHROPATHY]

Diabetes mellitus (DM) is the leading cause of end stage renal disease; 40% of the patients worldwide will require replacement therapy after 20 years of DM. Early-stage diabetic nephropathy is characterized by hyper filtration with micro-and macro albuminuria. Later on end-stage renal disease (ESRD) can appear; 40% of diabetic patients develop micro-and macrovascular complications, with increased risk among patients with genetic predisposition, such as Haptoglobin 2-2 phenotype. The most frequent complications are diabetic kidney disease, diabetic retinopathy and coronary artery disease. Chronic systemic inflammation and the inflammatory response, such as increased circulating cytokines have been recognized as main players in the development and progression of diabetic nephropathy. DM is also associated with increased oxidative stress, and alterations in carbohydrate, lipid and protein metabolism. Blocking the renin- angiotensin- aldosterone system (RAAS) is not sufficient to delay the progression of DM. Autophagy may be involved in the pathogenesis of diabetic nephropathy. Under normal blood glucose level, autophagy is an important protective mechanism in renal epithelial cells, including podocytes, proximal tubular, mesangial and endothelial cells. Down regulation of the autophagy mechanism, as in hyperglycemic condition, can contribute to the development and progression of DM. The recently used new family of drugs SGL2Tis (sodium-glucose cotransporter-2 inhibitors) reduces the typical glomerular hyper-filtration. Preclinical and clinical studies focusing on SGLT2I treatment have consistently demonstrated a reduction in albuminuria and maintenance of renal function. SGLT2 inhibition may lead to positive molecular changes in podocyte cells and proximal tubule cells by directly affect basal autophagy.

Alteration of autophagy-related protein 5 (ATG5) levels and Atg5 gene expression in diabetes mellitus with and without complications

BACKGROUND

Autophagy is a catabolic mechanism that involves lysosomal-dependent degradation of unnecessary intracellular components and responsible for normal cellular homeostasis. Autophagy pathway and its key participant ATG5/LC3 are associated with several pathologies such as diabetes mellitus and its complications.

METHODS

Levels and expression of autophagy key components ATG5 and LC3B were analyzed in both human model and murine tissues. One hundred and twenty human subjects were divided into four groups: Healthy (control), diabetes mellitus without complications, diabetic nephropathy, and diabetic retinopathy. Additionally, we used kidneys from WT healthy and diabetic nephropathy mice. Lysate derived from human peripheral blood mononuclear cells and murine renal cortex lysates were subjected to western blot and immunohistochemical analysis.

RESULTS

Western blot and immunohistochemical analysis demonstrate that ATG5 protein levels were significantly decreased in diabetes mellitus, diabetic nephropathy (DN), and diabetic retinopathy patients versus healthy controls and in DN mice compared to healthy mice (0.65 ± 0.04; 1.15 ± 0.13 A.U. units, respectively). Quantification of staining area (%) of ATG5 mice tissue expression also decreased in DN versus healthy mice (4.42 ± 1.08%; 10.87 ± 1.01%, respectively).

LC3B LEVELS AND EXPRESSION

Significant reduction in peripheral blood mononuclear cells in diabetic patients (with or without complications) vs. healthy controls. Renal LC3B levels were lower in DN versus healthy mice (0.36 ± 0.03; 0.68 ± 0.07 A.U. units). Renal LC3B staining quantification revealed significant reduction in DN versus healthy mice (1.7 ± 0.23%; 8.56 ± 1.7%).

CONCLUSION

We conclude that ATG5, as well as LC3B, are down regulated in diabetic patients with or without complications. This diminution contributes to deficiencies in the autophagy process.

P0760THE INFLUENCE OF MICROBIOME COMPOSITION ON THE DEVELOPMENT OF IGA NEPHROPATHY

Background and Aims

Overall, human microbiota contains 1014 bacterial cells. The human intestine is particularly dense of microbes, 1012 bacteria per g (dry weight), especially at colon level. Under healthy conditions, the human microbiota provides trophic and protective functions. Bacteroidaceae, and Prevotellaceae differed among IgA and Healthy Control subjects (HC). Enterobacteriaceae species were almost the highest in the fecal samples of patients.

Bifidobacterium species decreased in the fecal samples of Patients compared to HC subjects. Increasing evidence indicates that changes in the microbiota composition known as Dysbiosis, can affect human health and disease. Altering the balance of the gut microbiota can also affect kidney physiology and pathology, such as IgAN. we hypothesize that the aberrantly IgA1 that produced in IgAN in response to a mucosal infection may be influenced by the composition of the patient microbiome by inducing excessive abnormal mucosal IgA responses.

Study aim is to explore if IgAN patients have different microbiome composition compared with the healthy control individuals.

Method

Stool sample from 26 IgAN patients & from 26 healthy control individuals subjected to microbiome array and to taxonomic analysis, to characterize their microbiome compositions. Serum Creatinine\ albumin and urine proteinuria levels are used for evaluate the renal function of each IgAN patient. The clinical and laboratory evaluations will be crossed with the taxonomic data using statistical analysis methods.

Results

Based on our preliminary result with 11 IgAN patients and 11 healthy control individuals, there are significant differences in the microbiome composition between the two groups.

IgAN patients have a significant increase in the Bacteroides phylum accompanied with a significant decrease in the amount of both the Actinobacteria and Verrucomicrobia phyla, compared with the healthy individuals.

At the genus level, there is a significant increase in the Prevotella bacteria in the IgAN subjects compared with the healthy individuals.

Conclusion

1. A strong association between specific bacteria population and IgAN disease, we isolate specific population of bacteria that leads to IgAN or even aggravate its manifestation.

2. It may help to predict the tendency of each individual to develop IgAN and even predict the prognosis of each IgAN patient according to their microbiome.

3. it is rational to alter the intestinal barrier, the content of gut microbiota and its metabolites in the realm of CKD using different strategies such Prebiotics and symbiosis.

4. To develop disease-specific therapies based on microbiome modulations and manipulations such as modifying the gut microbiota through diet, antibiotic therapies, probiotic, bariatric surgery, fecal transplants.

P0977LOW EXPRESSION OF AUTOPHAGY-RELATED PROTEIN 5 (ATG5) LEADS TO SUPPRESSION OF AUTOPHAGY IN PATIENTS WITH DIABETIC NEPROPATHY AND RETINOPATHY

Background and Aims

Autophagy is a catabolic mechanism that involves lysosomal-dependent degradation of unnecessary or dysfunctional intracellular components. Autophagy plays role in many biological processes, including diabetic nephropathy (DN) and diabetic retinopathy (DR). Autophagy-related gene 5 (ATG5) is one of the most important participants in the autophagy mechanism. Deficiencies in ATG5 protein levels are associated with several diseases by influencing the level of autophagy pathway. Our study's aim was to investigate if aberrant expression of ATG5 protein or Atg5 gene is associated with DN or DR.

Method

The study included 120 human participants in 4 groups – Healthy, diabetic (DM), DN and DR; and 10 mice in 2 groups – healthy and DN. Western blot analyses of ATG5 and its downstream collaborator LC3B were performed on human white blood cell (WBC) lysates and murine renal lysates. Immunohistochemical analysis was performed on mice renal tissues. Quantitative real-time PCR analysis of ATG5 was performed on total mRNA isolated from human WBC.

Results

Conclusion

The Therapeutic Effect of Active Vitamin D Supplementation in Preventing the Progression of Diabetic Nephropathy in a Diabetic Mouse Model

BACKGROUND

Diabetic nephropathy (DN) is one of the most common microvascular complications of diabetes and is the leading cause of end-stage renal disease (ESRD) and replacement therapy worldwide. Vitamin D levels in DN patients are very low due to the decrease in the synthesis and activity of 1-α hydroxylase in the proximal tubule cells and decrease in the vitamin D receptor abundance. To date, few studies have shown the antioxidant effects of 1α,25-dihydroxyvitamin D₃ [1,25(OH)₂D₃] on hyperglycemia-induced renal injury. The selective activator of the vitamin D receptor, paricalcitol, reduces proteinuria and slows the progression of kidney injury. The precise mechanism through which vitamin D affects diabetic status and provides kidney protection remains to be determined.

METHODS

Diabetes mellitus (DM) was induced in 94 8-week-old DBA/2J mice by intraperitoneal injection of streptozotocin (STZ). DM mice were randomly divided into receiving vehicle or treatment with paricalcitol, the active vitamin D analog, 1 week after DM induction or paricalcitol treatment 3 weeks after DM induction. An additional control group of healthy wild-type mice was not treated. Urine albumin, blood urea nitrogen, and creatinine levels were measured before and at the end of the paricalcitol treatment. Periodic acid-Schiff, immunohistochemistry staining, and western blot of the renal tissues of vitamin D receptor, villin, nephrin, and podocin expressions, were analyzed.

RESULTS

Paricalcitol treatment restored villin, nephrin, and podocin protein levels that were downregulated upon DM induction, and reduced fibronectin protein level. Vitamin D receptor activation by paricalcitol may reduce proteinuria of DN in mice and alleviate high-glucose-induced injury of kidney podocytes by regulating the key molecules such nephrin-podocin.

CONCLUSIONS

Paricalcitol treatment was associated with improved structural changes in type 1 diabetic mice including upregulation of vitamin D receptor expression, and decreased fibrosis markers such as fibronectin. These effects may contribute to the consistent benefit of vitamin D analog to slow the deterioration in glomerular function and reduce the risk of ESRD in patients with type 1 and 2 diabetes mellitus. Our results suggest that additional use of paricalcitol may be beneficial in treating patients with diabetes under standard therapeutic strategies.

The Iron-Klotho-VDR Axis Is a Major Determinant of Proximal Convoluted Tubule Injury in Haptoglobin 2-2 Genotype Diabetic Nephropathy Patients and Mice

The haptoglobin (Hp) genotype (1-1 and 2-2) is a major determinant of nephropathy progression in diabetes mellitus patients. Hp 2-2 diabetic mice have impaired Hb clearance and increased iron deposits and oxidative stress in the proximal tubules (PCT), leading to increased renal injury. However, the precise mechanism of the PCT injury in diabetic nephropathy (DN) remains elusive. In the kidney, 1,25(OH)₂D3 suppresses the inflammatory response to renal tubular injury and requires normal renal expression of the α-klotho protein. In this study, we set out to test the hypothesis that the increased renal iron deposits in the PCT of Hp 2-2 DN affect the α-klotho-vitamin D receptor (VDR) axis and thereby exacerbates the PCT injury generated by the iron deposits. Immunohistochemical analysis of human and mouse kidney biopsies along with western blot analysis showed that the increased iron deposits in the PCT of the Hp 2-2 genotype were accompanied with significantly decreased α-klotho and VDR renal expression but significantly increased 1-α-hydroxylase renal expression. In conclusion, the iron-klotho-VDR axis is a major player in the mechanism contributing to iron-mediated PCT injury in diabetic Hp 2-2 mice and patients. Targeting this axis may open the way for new ideas regarding the pathogenesis and treatment of DN.

[HAPTOGLOBIN POLYMORPHISM AS AN INDEPENDENT PREDICTOR OF DIABETIC NEPHROPATHY AND RETINOPATHY]

The antioxidant protein haptoglobin (Hp) plays a major role in the development of diabetic complications such as diabetic nephropathy and retinopathy. In humans, two alleles of Hp were identified: 1 and 2 with three possible genotypes: 1-1, 2-1, and 2-2. The Hp protein products differ in their biochemical and biophysical properties, such as their antioxidant capacity. The Hp1 protein is superior to the Hp2 protein in binding to free hemoglobin and neutralizing its oxidative potential and the accompanying renal and retinal injury. Hence, diabetic patients with different Hp phenotypes have variable susceptibility to developing diabetic nephropathy and retinopathy. In diabetes, the kidney and the retinal injury progress gradually over time. Thus, understanding the factors that mediate the aggravation and progression of these complications is of critical importance. One of the latest hypotheses regarding the involvement of haptoglobin in the development of diabetic complications is its contribution to impaired vitamin D activation in the kidney. Over the last few years, great efforts were made in the field to explore this notion and decrypt the mechanism behind it. The goal in this area is that the research findings will be translated into clinical practice and lead to the development of a pharmacogenomics clinical approach that will deal with diabetic complications by selective administration of vitamin D according to the Hp genotype.

Interaction between the Haptoglobin 2 Phenotype and Diabetes Mellitus on Systolic Pulmonary Arterial Pressure and Nitric Oxide Bioavailability in Hemodialysis Patients

Elevated systolic pulmonary artery pressure (s-PAP, ≥35 mmHg) serves as an independent predictor of mortality in hemodialysis (HD) and diabetic (DM) patients. A polymorphism in the antioxidant Haptoglobin (Hp) gene has been shown to regulate the bioavailability of nitric oxide (NO), a major mediator of pulmonary vascular tone. We therefore set out to test the hypothesis that the Hp polymorphism may be a determinant of developing elevated s-PAP specifically in the DM state due to a decreased bioavailability of NO. To test our hypothesis we Hp typed and performed transthoracic echocardiography on a series of HD patients and stratified them into elevated and normal s-PAP groups and then evaluated whether there was a significant association between the Hp type, elevated s-PAP, and decreased NO bioavailability as defined by low plasma nitrite. We found a statistically significant interaction between the Hp type and DM on the prevalence of elevated s-PAP and lower mean nitrite levels with the combination of elevated s-PAP and low nitrite levels being significantly more prevalent in Hp 2-2 DM individuals. We conclude that the Hp 2 type is associated with elevated s-PAP levels and low plasma nitrite levels in HD patients specifically in the DM state.

A rare bacteremia caused by Cedecea davisae in patient with chronic renal disease

Patient:

Female, 77

Final Diagnosis:

Bacteremia

Symptoms:

Chills • diarrhea • fever • nausea

Medication:

—

Clinical Procedure:

X-Ray • CBC • urine and blood cultur

Specialty:

Infectious diseases

Objective:

Rare disease

Background:

Cedecea davisae is a gram negative, oxidase negative bacilli that include 5 species. In the medical literature there are very few reports that describe infections caused by different species of the Cedecea genus.

Case Report:

In this paper we report a fourth case of bacteremia in a 77 year-old patient with a chronic renal disease that was successfully treated with ceftazidim and ciprofloxacin. Additionally, we present a review of all the reported infections that were caused by C. davisae.

Conclusions:

Five cases (not including our report) of Cedecea bacteremia were reported so far. Cedecea infections and particularly C. davisae infections can be difficult to treat due to the antibiotic resistance of the bacterium. Therefore we propose to consider treating C. davisae bacteremia with a combined antibiotic treatment until getting laboratory results for antibiotic-sensitivity tests.

Toxicological significance of liver hypertrophy produced by inducers of drug-metabolizing enzymes

Changes in enzyme activity due to induction by chemicals is an important property that can determine the type of response seen in tissues exposed to environmental chemicals. Two major types of response, acute irreversible liver cell injury or death (necrosis) and long-term cancer induction, are discussed in terms of their modulation by enzyme induction. Most commonly, enzyme induction leads to a more severe toxic response by the liver, and to more cell death. However, inducers may have a protective effect, especially in carcinogenesis, when they most frequently protect against cancer induction if used early in the process. There is a discrepancy between this observation and the increase in mutagenic activity of liver preparations observed after induction. However, when enzyme induction occurs at a later stage, after initiation, it often accelerates or promotes cancer induction. Also, new cell populations constantly observed during liver carcinogenesis are composed of very hypertrophic hepatocytes containing a large amount of smooth endoplasmic reticulum. This is associated with a radical change in enzyme activities in the reticulum, which may account in part for the characteristic resistance exhibited by initiated cells to hepatotoxins and carcinogens. The resistance is considered to be an important property that may play a key role in the development of cancer under some circumstances.

Inexpensive detector for terahertz imaging

Glow discharge plasma, derived from direct-current gas breakdown, is investigated in order to realize an inexpensive terahertz (THz) room-temperature detector. Preliminary results for THz radiation show that glow discharge indicator lamps as room-temperature detectors yield good responsivity and noise-equivalent power. Development of a focal plane array (FPA) using such devices as detectors is advantageous since the cost of a glow discharge detector is approximately $0.2-$0.5 per lamp, and the FPA images will be diffraction limited. The detection mechanism of the glow discharge detector is found to be the enhanced diffusion current, which causes the glow discharge detector bias current to decrease when exposed to THz radiation.

Esophageal Varices: Evaluation with Esophagography with Barium versus Endoscopic Gastroduodenoscopy in Patients with Compensated Cirrhosis—Blinded Prospective Study

PURPOSE

To prospectively evaluate the accuracy of esophagography with barium in diagnosis of esophageal varices (EV) in patients with compensated cirrhosis, with endoscopic gastroduodenoscopy as the reference standard.

MATERIALS AND METHODS

In this study, which was approved by the local Helsinki Committee and in which all patients consented to participate, 61 patients with cirrhosis (34 men, 27 women; mean age, 61 years; range, 36-76 years) received a diagnosis clinically or with liver biopsy. In 87% (n = 53) of patients, Child-Pugh classification was A; in 13% (n = 8), Child-Pugh classification was B. They were evaluated with endoscopic gastroduodenoscopy, according to Japanese general criteria. Esophagography was performed within 3 weeks of endoscopic gastroduodenoscopy, and EV were assigned grades as follows: 0, no EV were seen; 1, EV manifested as very mild irregularities of the folds; and 2, the irregularity of the folds (EV) was clearly present. They were also assigned grades for shape and size: grade F0, no EV detected; grade F1, small straight EV; grade F2, slightly enlarged tortuous EV occupying less than one-third of esophageal lumen; and grade F3, large coil-shaped EV that occupied more than one-third of esophageal lumen. The sensitivity and specificity and positive and negative predictive values of esophagography for identification of each grade of EV were calculated separately, as was the 95% confidence interval.

RESULTS

All large EV (grades F2 and F3) were diagnosed at esophagography. Sensitivity declined with small EV (grade F1) to 71. The overall sensitivity of esophagography was 89% (95% confidence interval: 75.9%, 96.5%), the overall specificity was 83% (95% confidence interval: 64.5%, 94.7%), the overall positive predictive value was 89%, and the overall negative predictive value was 83% (95% confidence interval: 64.5%, 94.7%). Overall accuracy was 87%.

CONCLUSION

Esophagography is highly accurate in diagnosis of EV and can be considered a viable noninvasive alternative for determination of patients who should be selected for prophylactic treatment.

The resistance phenotype in the development and treatment of cancer

Phenotypic resistance, acquired early in carcinogenesis, has an established role in the pathogenesis of cancer in well-characterised experimental systems, and possibly also has a role in the origin of human cancer. It has been suggested that sunlight, an established risk factor for human skin carcinogenesis, is able to induce rare altered cells resistant to toxicity and to favour their clonal expansion via toxic effects exerted on normal keratinocytes. Other major risk factors for human neoplasia, including smoking and ageing, may also act partly through imposition of a constrained growth environment in the target organ to favour the emergence of altered resistant cells. Strategies aimed at counteracting this constrained environment could be effective in attenuating the force that sustains clonal expansion of altered cells.

Risk assessment for possible carcinogens: a critical look

Our overall understanding of mechanisms of toxicology in relation to human disease, with prevention of disease as a major objective, depends in part on the development of an adequate number of ways to assess risks, both short term and long term. Despite the cost, the long duration of the test, and some pitfalls, the long-term animal tests remain, to date, the only reliable assay for possible carcinogens. Recent work has concentrated increasingly on the development of short-term tests to replace the long-term tests. Such a development would be most welcome from several points of view. To date, a variety of approaches have been or are being used. These include (1) activation to an alkylating agent with DNA as the most important target, generating possible mutations in DNA and DNA damage with or without repair, (2) induction of cell proliferation, at least a few cycles, with DNA synthesis as the major target, again favoring mutations, and (3) decrease in cell-to-cell communication (gap-junctional intercellular communication) as a supposed test for promotion. None of these proposed assays are reliable indices for possible carcinogenic effects of chemicals or other agents; the scientific basis for this negative conclusion is discussed.

The slow induction of resistant hepatocytes during initiation of hepatocarcinogenesis by the nongenotoxic carcinogen clofibrate

This study was designed to explore whether a well-known nongenotoxic liver carcinogen, clofibrate, would induce rare resistant hepatocytes similar to those seen during initiation of hepatocarcinogenesis with many genotoxic carcinogens. Male young adult F344 rats were exposed to a control diet containing 0.5% (w/w) clofibrate for 3, 6, or 10 months. After 1 month on a diet free of clofibrate, the animals were assayed for resistant hepatocytes by a standardized selection procedure using 2-acetylaminofluorene as the inhibitor and partial hepatectomy as a strong stimulus for cell proliferation. No resistant hepatocytes were found in the animals exposed to clofibrate for 3 months or in any of a series of control animals. However, animals on the clofibrate for 6 and 10 months contained resistant hepatocytes that were clonally expanded to produce hepatocyte nodules. These nodules were indistinguishable on gross and microscopic examination from hepatocyte nodules seen in animals in which nodules are induced with one of many different genotoxic carcinogens. Also, like those nodules, the nodules seen in the animals exposed to clofibrate stained positively for glutathione S-transferase 1-1 and gamma-glutamyl transpeptidase and negatively for ATPase. The evidence from this study indicates that the nongenotoxic carcinogen, clofibrate, induces early cellular changes in the liver that are very similar to those induced by many different genotoxic carcinogens. These changes are manifest as a resistance phenotype in a few scattered hepatocytes that now can be clonally expanded selectively to form hepatocyte nodules. However, the resistant hepatocytes are induced by clofibrate much more slowly. Whether this basic similarity pertains to the later steps in the hepatocarcinogenic process remains to be studied.

A critical perspective in cancer research (Review)

Over the past few decades, there has been a tremendous increase in cancer biology data and treatment. Cancer research has opened exciting new areas of cellular and molecular biology. Month by month, new genes which regulate the carcinogenesis process are being discovered. The result is an incredible knowledge of cancer: what makes a cancer cell a cancer cell, what cancer cells need to develop, and how cancer cells behave, interact, overgrow and die. In parallel, gene manipulation within cells lets us foresee future possibilities of new cancer treatments. On the other hand, this combination of increased knowledge and powerful new techniques has provided no effective cancer therapy. As it has been quoted during the <Update and Intensive Review of Internal Medicine> meeting held in New York, August 1999: <. The success in treating Hodgkin's disease means that patients now live enough to develop complications related to the treatment>. Thus, after dedicated decades of excellent research, cancer remains a significant human, clinical, and economical burden. The purpose of this review is 2-fold. First, to analyze areas of basic cancer research that still await adequate scientific explanations. Second, to stress that, for its continuing advancement, cancer research is dependent upon close relationships among many disciplines; an intimate alignment of oncologists with biochemists, geneticists, immunologists, experimental pathologists, and pharmacologists is needed. In light of the great success registered at the basic science level but lack of effective therapies, it would be wise to establish human and economical resources addressed to a multidisciplinary collaborative effort in cancer research.