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.

Changes in drug-metabolizing enzymes of rats in ciprofibrate-induced hepatic nodules

1. Premalignant rat liver nodules produced in the resistant hepatocyte model, by exposure to carcinogenic chemicals (diethyl nitrosamine and 2-acetamidofluorene), and partial hepatectomy, exhibit decreased xenobiotic hydroxylase activities and increased conjugase activities, which are considered responsible for increased resistance to xenobiotic toxicity. 2. However, premalignant rat liver nodules generated by feeding the hypolipidaemic, peroxisomal proliferating drug, ciprofibrate, in a hypolipidaemic model, exhibit decreased hydroxylase activities but decreased conjugase activities also. 3. It is considered that reactive oxygen species (ROS) are generated in both the resistant hepatocyte model and in the hypolipidaemic model, resulting in lipid peroxidation, loss of haem, cytochromes and hydroxylase activities. 4. However, whereas there is a rebounding compensation of conjugase enzymes in the resistant hepatocyte model, this does not occur with the hypolipidaemic model, as peroxidation is probably persistent and the conjugases are continuously destroyed.

Chordoma: a case report

BACKGROUND

Chordomas are tumors of notochordal origin that account for approximately 1%-4% of all primary malignant bone tumors. The majority of patients with chordomas have a poor surgical prognosis due to extent of disease at diagnosis. These lesions have been previously classified based solely on their location.

METHODS

We describe here a case report of a posterior epidural C5-T1 chordoma that was discovered in a young patient who presented with weakness and paresthesia in all four extremities. This lesion was notable for its extraosseous and extradural characteristics.

RESULTS

C5-T1 laminectomy with gross total resection of the mass led to complete resolution of all symptoms. There has been no evidence of tumor recurrence to date.

CONCLUSIONS

We propose here a new classification system for chordomas that emphasizes the difference in resectability of these lesions depending on the space they occupy and the presence or absence of an osseous connection.

Alcohol and other chemicals in the development of hepatocellular carcinoma

A positive association between the incidence of hepatocellular carcinoma and the consumption of alcoholic beverages has been reported from some countries. The possible mechanistic nature of the association remains unclear, however. The effects of alcohol, as ethanol and as ethanol in various complex mixtures in the many different alcoholic beverages, were compared with the effects of well-known genotoxic and nongenotoxic or epigenetic carcinogens in carcinogenesis. There is no convincing evidence that alcohol can initiate the long multistep process of development of hepatocellular carcinoma. Thus, it appears that alcohol cannot be considered as a complete carcinogen. The effects of alcohol were also compared with known promoting agents for liver cancer. Although the available data are less clear, nevertheless it appears that alcohol cannot be considered as a bona fide promoting agent for liver cancer development. The most likely roles of alcohol in the genesis of liver cancer are: (1) to induce a well-known precancerous liver lesion, cirrhosis, and (2) to modulate, in an as yet ill-defined manner, the process of cancer development with known human carcinogenic influences such as hepatitis due to hepatitis B and hepatitis C viruses. Alcohol is well known to induce several enzymes in the liver and, thus, could theoretically modulate one or more steps in the carcinogenic process. Because alcohol has been found to alter cell membranes in well-defined ways and cell membrane changes, especially in the liver endoplastic reticulum, appear to be common in the later steps in liver cancer development, it is suggested that one site of alcohol action might be in the modulation of the biophysical composition of the liver endoplasmic reticulum and plasma membrane, favoring the cellular evolution to neoplasia.

Changes in tRNA pattern in ethionine-induced rat putative preneoplastic hepatocyte nodules

As part of a study to explore further the biochemical pathology of chemical hepatocarcinogenesis, cytoplasmic tRNA patterns have been studied in ethionine-induced rat putative preneoplastic nodules in comparison to surrounding non-nodular liver and control liver. A new h.p.l.c. methodology, able to resolve contemporaneously the numerous components in a tRNA population, has been used. The results obtained indicate the presence of marked differences in the chromatographic profiles of hepatocyte nodules, non-nodular surrounding liver and control liver. The differences are both quantitative and qualitative, with some chromatographic peaks showing increases and some decreases or absences. Also, new peaks are seen reproducibly in the nodules. The data show major changes in the tRNA population during hepatocarcinogenesis that might have mechanistic implications.

Effects of peroxidative stress and age on the concentration of a deoxyguanosine-malondialdehyde adduct in rat DNA

The effect of age and peroxidative stress on the concentration of a deoxyguanosine malondialdehyde adduct (dG-MDA) in rat tissues was investigated. Vitamin E deficiency had no effect on the dG-MDA content of liver DNA in rats fed a diet containing 10% corn oil. When 2% cod liver oil was added to this diet, the dG-MDA content of liver DNA doubled in the positive controls fed a high level of vitamin E (100 ppm dl-alpha-tocopherol), and there was a further increase when vitamin E was deleted. Neither iron nitrilotriacetate administration nor choline deficiency had any effect on the dG-MDA content of liver DNA. Carbon tetrachloride had a lowering effect. The failure of iron or carbon tetrachloride administration and of vitamin E deficiency to increase liver dG-MDA is consistent with their failure in previous experiments to affect the urinary excretion of dG-MDA. In contrast, these forms of peroxidative stress produce large increments in the urinary excretion of MDA adducts with lysine, reflecting increased formation and degradation of MDA-modified proteins. DNA appears to be protected from modification by MDA produced at extranuclear sites. The frequency of dG-MDA in different tissues of 4-month-old rats varied markedly: brain >> liver > kidneys and testes. Higher concentrations of dG-MDA were found in the liver and kidneys, but not the testes, of 25-month-old rats. The determinants of the concentration of dG-MDA in DNA merit further investigation.

Liver biochemical pathology of choline deficiency and of methyl group deficiency: a new orientation and assessment

New information on the pathologic effects of a choline deficient diet in the rat, in relation to the biochemical events, has led to a new understanding and orientation of the pathogenesis of both acute and chronic consequences in the liver. The biochemical pathology of choline deficiency is quite different than that of methyl group (lipotrope) deficiency. These studies in our laboratory and elsewhere are generating new insights and hypotheses concerning the genesis of hepatocyte necrosis and hepatocellular carcinoma in the rat fed a choline deficient diet.

An origin of presumptive preneoplastic foci and nodules from hepatocytes in chemical carcinogenesis in rat liver

The sites and times of appearance of preneoplastic foci in rat liver acinus during the first 11 days after initiation with diethylnitrosamine and promotion with 2-acetylaminofluorene plus partial hepatectomy was observed in three separate experiments. Foci appeared as alterations of hepatocytes followed by focal proliferation in each of the three zones before any ductular epithelial cell ('oval cell') proliferation. The dissociation between foci and 'oval cell proliferation' is strong evidence against a role of the latter in generating preneoplastic hepatocytes in hepatocellular carcinogenesis.

Hypermethylation of replicating hepatic DNA following N-methyl-N-nitrosourea administration

Changes in the degree of methylation of cytosine in DNA are considered to be mechanistically important in modulating gene expression. To gain a better understanding of the relationship(s) linking onco-proliferative processes and enzymatic DNA methylation, a study has been carried out on the hepatic DNA methylation pattern during DNA replication following partial hepatectomy (PH), mitogen treatment and N-methyl-N-nitrosourea (MNU) administration in rats. The following results were obtained: (i) DNA hypomethylation was seen during DNA synthesis, with each of the 3 stimuli, namely MNU administration, partial hepatectomy, and hepatomitogen treatment; (ii) the level of DNA hypomethylation was not quantificatively related to the extent of DNA replication as measured by incorporation of [3H]thymidine into hepatic DNA; (iii) MNU administration under conditions conducive to carcinogenic development, i.e. during the S phase of compensatory cell proliferation, caused hypermethylation of replicating hepatic DNA, as shown by HpaII and MspI restriction patterns.

Programmed cell death: necrosis versus apoptosis

Cell death remains poorly understood, despite its obvious importance in every organ and tissue in a wide variety of biological processes, including, of course, the many pathological. The past few years have seen an amazing expansion of interest in cell death in normal development and maturation, in the pathogenesis of many acute and chronic diseases, and in the therapy of some diseases, especially malignant neoplastic diseases and some hyperplastic diseases such as psoriasis. This expansion has included an unusual interest in a supposedly new form of cell death, a "programmed cell death," designated "apoptosis." This is proposed as a hitherto undescribed form of cell death in contrast to the classical cell death, necrosis. Apoptosis is considered by some, especially by nonpathologists, to represent quite a different type of cell death. A review of the literature on on apoptosis, programmed cell death, necrosis, etc. indicates that there is no field of basic cell biology and cell pathology that is more confusing and more unintelligible than the area of apoptosis versus necrosis. If any degree of clarity is to develop in our understanding of the fundamental principles underlying cell death of any type, it is incumbent upon us to rethink "from square one" the scientific analysis of how cells die and how can we assess cell death in a reasonably rational manner.

Multiple sites of control of glutathione S-transferase P1-1 in rat liver

Glutathione transferase P1-1, normally very low in adult rat liver, is induced by a single intravenous dose of lead nitrate. In this transient induction, there are at least three sites of regulation or control. These are transcription, post-transcription, and post-translation. The increase in transcription is evident both by nuclear run-off analysis and by measurement of mRNA levels. The other two sites of control were seen in actinomycin D-treated animals in which RNA synthesis was inhibited by over 80%. Treatment with actinomycin D increases the stability of the mRNA and also somehow inhibits the conversion of a glutathione transferase protein to an enzymatically active form. These three sites offer possibilities for the study of mechanisms of control for this interesting enzyme that may play a role in chemical carcinogenesis and in drug resistance.

Altered expression of cytochrome P450 mRNA during chemical-induced hepatocarcinogenesis and following partial hepatectomy

Levels of various cytochrome P450 proteins have been reported to be decreased to varying degrees in chemically induced hepatocyte nodules and following partial hepatectomy (PH). By screening a rat liver lambda ZAP cDNA expression library with antibodies raised against a partially purified preparation of cytochrome P450 isolated from untreated male Fischer 344 rats, we have isolated a 1.1-kb cDNA. This cDNA was sequenced for 139 bases from the 5' end of the sense strand and comparison of the resulting sequence with the sequences in Gene Man DNA data bank revealed 95% homology of the sequenced portion with male-specific rat cytochrome P450 (M-1, CYP IIC11). The 32P-labeled cDNA was used as a hybridization probe on RNA blots (Northern blots) prepared with total RNA from rat livers obtained post PH, from aflatoxin B1(AFB1)-induced rat liver tumors and from rat liver nodules induced with a combination of diethylnitrosamine/acetylaminofluorene/PH (DEN/AFF/PH). At 36 and 72 hr post PH, the mRNA level was decreased by > 93%. Relative to the corresponding control livers, the mRNA level was also decreased by 97% in the liver nodules and by 57% in AFB1-induced liver tumors. The RNA blots derived from the liver nodules and AFB1-induced liver tumors were also probed with a cDNA probe (R17) that recognizes other cytochromes P450 (CYP IIB1/CYP IIB2). The mRNA corresponding to CYP IIB1/CYP IIB2 was also depressed 92% in the nodules and 65% in the tumors. These results clearly indicate that the depression of both CYP IIC11 and IIB1/IIB2 in the hepatic nodules and the tumors is related to the inhibition of transcription and/or enhanced degradation of the mRNA.

Small encapsulated hepatocellular carcinoma of the liver. Provisional analysis of pathogenetic mechanisms

BACKGROUND

Small hepatocellular carcinomas frequently were found incidentally during routine pathologic examinations of adult livers removed at liver transplant.

METHODS

Sixty-nine carcinomas of all sizes were found in 25 patients; 39 of the tumors were smaller than 1 cm in diameter, and 18 of the carcinomas in five patients were not clinically suspected. These small incidental carcinomas lend themselves to analysis of the morphologic basis of human hepatocellular carcinogenesis.

RESULTS

All of these tumors arose in cirrhotic livers. Most of the small carcinomas were multilobulated and subdivided by pre-existing fibrous septa. The surrounding capsule usually was not a true capsule. They were all well differentiated, most formed bile, Mallory bodies, or showed alpha-1-antitrypsin (A1AT) positivity. Transition from cirrhotic nodular parenchyma to areas of hyperplasia or atypical hyperplasia to well-differentiated carcinoma were common. Large cell dysplasia also was common.

CONCLUSIONS

These morphologic transitions closely parallel changes seen in experimental chemical carcinogenesis. They also strongly suggest a multicentric origin of the tumors. In addition, in every instance, the lesions were multiple in the liver and involved both lobes. This latter finding has possible implications for recurrence after local surgical excision of small hepatocellular carcinomas.

Sequential alterations in tRNA population of 2-acetylaminofluorene-induced hepatocyte nodules

In order to investigate the possible mechanisms by which cellular alterations can start an altered onco-developmental gene expression, we studied tRNA distribution profiles during the early steps of 2-acetylaminofluorene-induced hepatocarcinogenesis. The finding of progressive and sequential alterations appears to support the hypothesis of a causal connection between tRNA changes and nodular cell proliferation, possibly through the disruption of the mechanism which regulates tRNA functional adaptation.

Choline deficiency, lipotrope deficiency and the development of liver disease including liver cancer: a new perspective

Thus, the pathologic consequences of feeding a CD diet are fatty liver, liver cell death, liver cell proliferation, and liver cell cancer. The fatty liver with CD is similar to that with other types of fatty liver in that the most attractive current hypothesis is based on some interference with the production and output of VLDL by the liver. The induction of cell death appears to be consistent with quite a different hypothesis, genesis and/or increase in liver free radicals leading to both acute necrosis and initiation of carcinogenesis. Especially noteworthy is the low incidence of liver cirrhosis, even after 2 years of exposure to the CD diet. The feeding of the CD diet reproducibly induces severe and persistent fatty liver coupled with extensive cell death, a combination that is frequently considered to be appropriate for the induction of "micronodular" (fatty) cirrhosis in humans. The findings with the LD diet, the high incidence of cirrhosis, with severe persistent fatty liver without significant cell death, together with the low incidence of cirrhosis with the CD diet, stand out as unpredictable and strange, according to current concepts of the pathogenesis of human cirrhosis. The CD model offers an unusual opportunity to explore in increasing detail the possible roles of free radicals in two important problems in pathology and medicine-acute cell injury and neoplasia. The challenges include mechanistic studies on how the free radicals are generated and how they relate to the biological consequences. The relatively slow sequential changes in the induction of cell injury and neoplasia makes the CD model one of the best for mechanistic studies relating to free radicals.

Is carcinogenesis fundamentally adversarial-confrontational or physiologic-adaptive?

The dominant dogma concerning the essential cellular changes during preneoplasia and precancer considers these as abnormal or foreign that evoke a basic "host-parasite" response. An alternative view of how cancer develops, here briefly outlined, views the early and intermediate cellular changes as essentially physiologic and adaptive. This different concept introduces clonal adaptation as a basic response to many genotoxic carcinogenic stimuli including chemicals, radiations, and some viruses. The evidence in support of this new view of the carcinogenic process is summarized.

Effect of MNU on the methylation pattern of hepatic DNA during compensatory cell proliferation

We have used the initiation-promotion model of MNU-induced hepatocarcinogenesis to test the hypothesis that alteration of the methylation status of DNA cytosines could be involved in the initiation of carcinogenesis. In fact cell proliferation plays a fundamental role in the initiation of liver carcinogenesis and hepatocytes in the S phase are more sensitive towards MNU initiation than at other times in the cycle. The molecular mechanisms involved in these processes, however, are still poorly understood and it seemed of value to monitor the DNA methylation status in this system. The results obtained indicate that MNU hepatocarcinogenic action might consist also of the inhibition of DNA hypomethylation biologically associated with cell proliferation.

The cancer-initiating potential of the fumonisin B mycotoxins

The cancer-initiating potential of the fumonisin B (FB) mycotoxins produced by Fusarium moniliforme was screened in rat liver for their ability to induce rare hepatocytes with an acquired resistance to the mitoinhibitory effect of 2-acetyl-aminofluorene (2-AAF). Two different initiating protocols were used: a feeding regimen during which FB1 was fed at a dietary level of 0.1% for 26 days, and another where single or multiple doses of FB1 and FB2 (varying from 200 to 50 mg/kg) were administered (by gavage) to hepatectomized rats. In both cases promotion was effected by a 2-acetylamino-fluorene/carbontetrachloride treatment. Cancer initiation was only obtained after the prolonged feeding regimen, indicating that the fumonisins are poor cancer initiators. FB1 and FB2 also lack genotoxic effects in the in vivo and in vitro DNA repair assays in primary hepatocytes. Although FB1 primarily affects the liver, it is not very cytotoxic to primary hepatocytes when compared to aflatoxin B1.