Hydroxyl Radical-induced Strand Break Formation of Poly(U) in Anoxic Solution. Effect of Dithiothreitol and Tetranitromethane

Summary

The role of dithiothreitol (DTT) and tetranitromethane (TNM) on the yields of radiation-induced strand break formation in polyuridylic acid (poly(U)) was studied in anoxic aqueous solutions at neutral pH by low-angle laser light-scattering. From G (single-strand breaks) as a function of DTT concentration it follows that two different processes lead to OH radical-induced single-strand break (ssb) formation. Only one of the two processes, which accounts for 80 per cent of the ssb formation, is inhibited by DTT, the other one, 20 per cent, is not inhibited. The ‘repair’ process is attributed to H-donation to the C-6-yl radical of the uracil moiety. The C-6-yl radical is produced by OH addition to the C-5 position of the uracil moiety. It follows that the sugar radicals, in contrast to earlier suggestions, do not seem to be repaired by DTT at the low concentrations used. The strand break formation not inhibited by DTT is induced by radicals other than the uracil-6-yl radical, e.g. the uracil-5-yl or the OH radicals reacting with the sugar moiety. The strong reduction of G(ssb) from 2·3 to 0·2 on addition of TNM is also discussed.     

Hair trace elementary profiles in aging rodents and primates: links to altered cell homeodynamics and disease

Aging is associated with an increased incidence of pathological conditions such as neurodegeneration, cardiovascular and renal disease, and cancer. These conditions are believed to be linked to a disruption in cell homeodynamics, which is regulated by essential trace elements. In this study we used hair elementary analysis by inductively coupled plasma mass spectrometry (ICPMS) to examine age-related profiles of 47 elements in both rats and common marmoset monkeys. Hair was collected from young adult (6 months) and aged (18 months) Long–Evans male rats, and young adult (2 years), middle-aged (4 years) and aged (>8 years) marmosets. The results revealed that aging reduces content levels of cobalt, potassium and selenium while content levels of aluminium, arsenic, boron, mercury, molybdenum, and titanium were elevated in aged rats. Similarly, aged marmosets showed reduced levels of cobalt and elevated levels of aluminium. Case studies in aged rats revealed that myocardial infarction was associated with elevated levels of sodium, potassium and cadmium and reduced zinc, while renal failure was linked to elevated content of potassium, chloride and boron and reduced contents of manganese. Carcinoma was linked to elevated arsenic and reduced selenium levels. These findings indicate that hair elementary profiles in healthy aging and age-related diseases reflect altered cell and organ metabolic functions. Cobalt and aluminium in particular may serve as biomarkers of aging in animal models. Thus, elementary deposition in hair may have predictive and diagnostic value in age-related pathological conditions, including cardiovascular and kidney disease and cancer.     

Angiotensin receptor antagonists in patients with nephropathy due to type 2 diabetes

In the past few years diabetes has become the leading cause of end-stage renal disease in all Western countries. A correlation between blood pressure and rate of progression in diabetic nephropathy was noted very early, and increased local activity of the renin angiotensin system was identified as a major pathophysiological mechanism for proteinuria and nephrosclerosis in diabetic patients. Angiotensin converting enzyme (ACE) inhibitors have been shown to slow progression of nephropathy in type 1 diabetic patients. The majority of diabetic patients with nephropathy, however, are suffering from type 2 diabetes and until last year there was no convincing evidence of ACE inhibitors being able to slow progression in type 2 diabetic patients with nephropathy. Three new studies now fill this gap, showing that angiotensin receptor blockers (ARB) are nephroprotective in patients with type 2 diabetes, independently of blood pressure. This review provides an in-depth discussion of the results of these studies and provides recommendations for patient management.     

Case Report: Halicephalobus gingivalis: A Rare Cause of Fatal Meningoencephalomyelitis in Humans

The genus Halicephalobus consists of eight species of free-living nematodes. Only one species (H. gingivalis) has been reported to infect vertebrates. Human infection is extremely rare, and only four cases have been reported in the literature. These nematodes seem to exhibit neurotropism, but their life cycle, mode of infection, and risk factors are poorly understood. Neurohelminthiases are not commonly recognized in the United States and when they do occur, pose great diagnostic challenges because of lack of appropriate non-invasive screening and/or confirmatory tests. We report a challenging case of meningoencephalomyelitis caused by a Halicephalobus sp., in which the patient had a rapidly deteriorating clinical course. The case did not raise any clinical suspicion of neurohelminthiases, although increased eosinophils were present in the cerebrospinal fluid. This case presents an opportunity to highlight the importance of considering parasitic infection in meningoencephalitis or meningoencephalomyelitis presenting atypically.     

Case Report: Zoonotic Onchocerca lupi Infection in a 22-Month-Old Child in Arizona: First Report in the United States and a Review of the Literature

A 22-month-old girl presented with neck pain and stiffness and magnetic resonance imaging showed an extradural mass extending from C2 through the C4 level with moderate to severe compression of the cord. A left unilateral C2–C4 laminectomy was performed revealing an extradural rubbery tumor; a small biopsy was obtained. Examination of stained tissue revealed the presence of a parasitic worm that was identified as a gravid female Onchocerca lupi. A magnetic resonance imaging at 7 weeks follow-up showed a significantly decreased size of the enhancing lesion and the patient''s symptoms gradually resolved. This is the first report of zoonotic O. lupi in the United States. The parasite has been reported in dogs and cats in the western United States, and from people in four cases reported from Europe. A great deal more needs to be learned, including full host range and geographic distribution, before we fully understand O. lupi infections in animals and man.     

Die chromosomalen Veränderungen in der Rattenleber während der krebsigen Entartung nach Verfütterung von Buttergelb

Zusammenfassung Erwachsene Ratten wurden mit 4-Dimethylaminoazobenzol (“Buttergelb”) gefüttert und die Mitosen der Leberkerne nach Aufnahme verschiedener Buttergelbmengen (200–1020 mg) auf Chromosomenzahlen und Mitoseanomalien hin untersucht. Um mehr Teilungsstadien zu erhalten, wurde die Leber 48 Std vor der Fixierung partiell hepatektomiert. Auch in buttergelbbehandelten Rattenlebern ist ein Mitosemuster vorhanden, dessen Zusammensetzung sich w?hrend der Buttergelbbehandlung in charakteristischer Weise ver?ndert: Mit steigender Buttergelbdosis nehmen die diploiden Mitosen stark ab (von 44% auf 10%), die aneuploiden Stadien stark zu (von 13% auf 60%). Die Ver?nderungen vom euploiden (diploiden) zum aneuploiden Mitosemuster gehen sprunghaft vor sich, wobei die erste Reaktionsschwelle nach 300 mg Buttergelbaufnahme liegt. Bei 939 untersuchten aneuploiden Metaphasen finden sich Chromosomenzahlen zwischen 6 und 192. Von den in diesem Bereich enthaltenen 178 m?glichen aneuploiden Zahlen sind nur 50 realisiert. Die Zahlen 27, 33, 36, 48, 54, 69, 75, 96 sind dabei besonders h?ufig (78,5% aller aneuploiden Metaphasen). Mit steigender Buttergelbdosis kommen zus?tzlich zu den bereits bevorzugt auftretenden vier aneuploiden Zahlen der unbehandelten Leber weitere aneuploide Zahlen als bevorzugt hinzu, deren H?ufigkeit mit steigender Dosis ansteigt. Ferner treten neue aneuploide, nicht bevorzugte Chromosomenzahlen auf. Sowohl für die neuauftretenden, bevorzugten wie nicht bevorzugten Klassen ist eine an bestimmte Buttergelbdosen gebundene Entstehung charakteristisch. Mit 4 Textabbildungen     

A controlled trial of glucagon in acute experimental pancreatitis in rats

Acute pancreatitis was induced in 245 rats by retrograde instillation of Na-taurocholate into the pancreatic duct. Mortality rate in animals treated 6-hourly with glucagon (1 mg/kg) after induction of pancreatitis was 50% as compared to 30% deaths in the controls treated with 0,9% NaCl (chi2-test: p less than 0,05). Mortality rate in animals treated 6-hourly with the same dose of glucagon before induction of pancreatitis was 36,5% as compared to 28% deaths in the corresponding controls (chi2-test: p greater than 0,05). Glucagon in lower doses (0,1-0,5 mg/kg every 6 hours) did not alter mortality rates as compared to animals treated with 0,9% NaCl. 2. A nonletal form of pancreatitis was induced in 26 rats by ligation of the pancreatic duct. Injection of glucagon (1 mg/kg) seemed to suppress amylase activities in blood for a short period of appr. 1 hour. However, 7 and 9 hours after induction of pancreatitis, amylase activities were significantly higher in animals treated one or two times with glucagon as compared to untreated controls. It is concluded that glucagon in the high dose of 1-4 mg/kg/24 hours does not only not influence the course of acute experimental pancreatitis in rats but can even deteriorate it.     

In vitro and in vivo metabolism and detection of 3‐HO‐PCP,a synthetic phencyclidine,in human samples and pooled human hepatocytes using high resolution mass spectrometry

The new psychoactive substance (NPS) 3‐HO‐PCP, a phencyclidine (PCP) analog, was detected in a law enforcement seizure and in forensic samples in Denmark. Compared with PCP, 3‐HO‐PCP is known to be a more potent dissociative NPS, but no toxicokinetic investigations of 3‐HO‐PCP are yet available. Therefore, 3‐HO‐PCP was quantified in in vivo samples, and the following were investigated: plasma protein binding, in vitro and in vivo metabolites, and metabolic targets. All samples were separated by liquid chromatography and analyzed by mass spectrometry. The unbound fraction in plasma was determined as 0.72 ± 0.09. After in vitro incubation with pooled human hepatocytes, four metabolites were identified: a piperidine‐hydroxyl‐and piperidine ring opened N‐dealkyl‐COOH metabolite, and O‐glucuronidated‐ and O‐sulfate‐conjugated metabolites. In vivo, depending on the sample and sample preparation, fewer metabolites were detected, as the O‐sulfate‐conjugated metabolite was not detected. The N‐dealkylated‐COOH metabolite was the main metabolite in the deconjugated urine sample. in vivo analytical targets in blood and brain samples were 3‐HO‐PCP and the O‐glucuronidated metabolite, with 3‐HO‐PCP having the highest relative signal intensity. The drug levels of 3‐HO‐PCP quantified in blood were 0.013 and 0.095 mg/kg in a living and a deceased subject, respectively. The 3‐HO‐PCP concentrations in deconjugated urine in a sample from a living subject and in post‐mortem brain were 7.8 and 0.16 mg/kg, respectively. The post mortem results showed a 1.5‐fold higher concentration of 3‐HO‐PCP in the brain tissue than in the post mortem blood sample.     

Mitral annular calcification in the elderly – Quantitative assessment

PurposeTo determine the reliability of subjective and objective quantification of mitral annular calcification (MAC) in elderly patients with severe aortic stenosis, to define quantitative sex- and age-related reference values of MAC, and to correlate quantitative MAC with mitral valve disease.MethodsIn this retrospective, IRB-approved study, we included 559 patients (268 females, median age 81 years, inter-quartile range 77–85 years) with severe aortic stenosis undergoing CT. Four independent readers performed subjective MAC categorization as follows: no, mild, moderate, and severe MAC. Two independent readers performed quantitative evaluation of MAC using the Agatston score method (Agatston_MAC). Mitral valve disease was determined by echocardiography.ResultsSubjective MAC categorization showed high inter-reader agreement for no (k ?= ?0.88) and severe MAC (k ?= ?0.75), whereas agreement for moderate (k ?= ?0.59) and mild (k ?= ?0.45) MAC was moderate. Intra-reader agreement for subjective MAC categorization was substantial (k ?= ?0.69 and 0.62). Inter- and intra-reader agreement for Agatston_MAC were excellent (ICC ?= ?0.998 and 0.999, respectively), with minor inconsistencies in MAC involving the left ventricular outflow tract/aortic valve. There were significantly more women than men with MAC (n ?= ?227, 85% versus n ?= ?209, 72%; p ?< ?0.001), with a significantly higher Agatston_MAC (median 597, range 81–2055 versus median 244; range 0–1565; p ?< ?0.001), particularly in patients ≥85 years of age. Agatston_MAC showed an area-under-the-curve of 0.84 to diagnose mitral stenosis, whereas there was no association of Agatston_MAC with mitral regurgitation (p ?> ?0.05).ConclusionsOur study in elderly patients with severe aortic stenosis shows that quantitative MAC scoring is more reliable than subjective MAC assessment. Women show higher Agatston_MAC scores than men, particularly in the elderly population. Agatston_MAC shows high accuracy to diagnose mitral stenosis.