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Biomedical subjects

A Adler

Publications and source records attributed to A Adler.

At least 19 recordsLinked to original sources
PubMed2007

Precision-controlled elution of a 82Sr/82Rb generator for cardiac perfusion imaging with positron emission tomography.

A rubidium-82 ((82)Rb) elution system is described for use with positron emission tomography. Due to the short half-life of (82)Rb (76 s), the system physics must be modelled precisely to account for transport delay and the associated activity decay and dispersion. Saline flow is switched between a (82)Sr/(82)Rb generator and a bypass line to achieve a constant-activity elution of (82)Rb. Pulse width modulation (PWM) of a solenoid valve is compared to simple threshold control as a means to simulate a proportional valve. A predictive-corrective control (PCC) algorithm is developed which produces a constant-activity elution within the constraints of long feedback delay and short elution time. The system model parameters are adjusted through a self-tuning algorithm to minimize error versus the requested time-activity profile. The system is self-calibrating with 2.5% repeatability, independent of generator activity and elution flow rate. Accurate 30 s constant-activity elutions of 10-70% of the total generator activity are achieved using both control methods. The combined PWM-PCC method provides significant improvement in precision and accuracy of the requested elution profiles. The (82)Rb elution system produces accurate and reproducible constant-activity elution profiles of (82)Rb activity, independent of parent (82)Sr activity in the generator. More reproducible elution profiles may improve the quality of clinical and research PET perfusion studies using (82)Rb.

Algorithms↗
PubMed2006

Objective selection of hyperparameter for EIT.

An algorithm for objectively calculating the hyperparameter for linearized one-step electrical impedance tomography (EIT) image reconstruction algorithms is proposed and compared to existing strategies. EIT is an ill-conditioned problem in which regularization is used to calculate a stable and accurate solution by incorporating some form of prior knowledge into the solution. A hyperparameter is used to control the trade-off between conformance to data and conformance to the prior. A remaining challenge is to develop and validate methods of objectively selecting the hyperparameter. In this paper, we evaluate and compare five different strategies for hyperparameter selection. We propose a calibration-based method of objective hyperparameter selection, called BestRes, that leads to repeatable and stable image reconstructions that are indistinguishable from heuristic selections. Results indicate: (1) heuristic selections of hyperparameter are inconsistent among experts, (2) generalized cross-validation approaches produce under-regularized solutions, (3) L-curve approaches are unreliable for EIT and (4) BestRes produces good solutions comparable to expert selections. Additionally, we show that it is possible to reliably detect an inverse crime based on analysis of these parameters.

Algorithms↗
PubMed2006

Infectious complications of implantable ports and Hickman catheters in paediatric haematology-oncology patients.

The aim of this study was to define and compare the infectious and non-infectious complications associated with Hickman catheters and implantable ports in children. The study was conducted over a three-year period in the Department of Haematology-Oncology at the Schneider Children's Medical Center of Israel. All patients who required a central venous catheter (CVC) were included in the study. For each episode of catheter-associated bloodstream infection, demographic, clinical and microbiology data were recorded. During the study period, 419 tunnelled CVCs (246 implantable ports and 173 Hickman) were inserted in 281 patients. Compared with implantable ports, Hickman catheters were associated with a significantly higher rate of bloodstream infections (4.656 vs 1.451 episodes per 1000 catheter-days), shorter time to first infection (52.31 vs 108.82 days, P < 0.001), shorter duration of catheterization (140.75 vs 277.28 days, P < 0.001), and higher rate of removal because of mechanical complications (P < 0.005). Gram-positive bacterial infections were more prevalent in the implantable port group (63.6% vs 41.6%), whereas Gram-negative rods, polymicrobial infections and mycobacterial infections were more prevalent in the Hickman group (31.4% vs 50.9%, 17% vs 36% and 0% vs 4.4%, respectively; P < 0.05 for all). Haematopoietic stem cell transplantation was identified as an independent risk factor for infection [odds ratio (OR) -1.68, P = 0.005] and for catheter removal due to complications (OR -2.0, P < 0.001). Implantable ports may be considered the preferred device for most paediatric oncology and stem cell transplantation patients.

Adolescent↗
PubMed2006

RNA aptamers as potential pharmaceuticals against infections with African trypanosomes.

Protozoal pathogens cause symptomatic as well as asymptomatic infections. They have a worldwide impact, which in part is reflected in the long-standing search for antiprotozoal chemotherapy. Unfortunately, effective treatments for the different diseases are by and large not available. This is especially true for African trypanosomiasis, also known as sleeping sickness. The disease is an increasing problem in many parts of sub-Saharan Africa, which is due to the lack of new therapeutics and the increasing resistance against traditional drugs such as melarsoprol, berenil and isometamidium. Considerable progress has been made over the past 10 years in the development of nucleic acid-based drug molecules using a variety of different technologies. One approach is a combinatorial technology that involves an iterative Darwinian-type in vitro evolution process, which has been termed SELEX for "systematic evolution of ligands by exponential enrichment". The procedure is a highly efficient method of identifying rare ligands from combinatorial nucleic acid libraries of very high complexity. It allows the selection of nucleic acid molecules with desired functions, and it has been instrumental in the identification of a number of synthetic DNA and RNA molecules, so-called aptamers that recognize ligands of different chemical origin. Aptamers typically bind their target with high affinity and high specificity and have successfully been converted into pharmaceutically active compounds. Here we summarize the recent examples of the SELEX technique within the context of identifying high-affinity RNA ligands against the surface of the protozoan parasite Trypanosoma brucei, which is the causative agent of sleeping sickness.

Animals↗
PubMed2006

Exserohilum: an emerging human pathogen.

Exserohilum is a dematiaceous fungus that may cause a spectrum of diseases in humans, including skin and corneal infection, invasive disease, and allergic fungal sinusitis. The aim of this work is to describe two new cases of Exserohilum infection and to review the literature. The review yielded 33 cases of Exserohilum infection, of which 23 were reported since 1993. Most occurred in regions with hot climates, such as India, Israel, and the southern USA. Impaired immunity was present in the majority of patients with invasive and skin infections, whereas local trauma and atopy were the predisposing factors in those with corneal infections and allergic fungal sinusitis, respectively. Surgical debridement was the principal mode of therapy for allergic fungal sinusitis. Amphotericin B was the initial single antifungal agent used in all cases of invasive disease; the response rate was low but improved with the addition of triazole agents. Outcome appeared to be better than for other mold infections and depended mainly on the underlying diseases.

Adolescent↗
PubMed2005

Fate of heavy metals after application of sewage sludge and wood-ash mixtures to short-rotation willow coppice.

Short-rotation willow coppice (SRWC), grown on farmland in Sweden for energy-biomass production, was fertilised with sewage sludge and wood-ash mixtures on the basis of the permitted annual phosphorus supply. Two identical experiments were conducted in central Sweden, on two newly harvested commercial SRWC fields. The maximum legally permitted amount of the sludge-ash mixture, sludge only, ash only, and twice the maximum permitted sludge-ash amount, were applied. The aim was to assess the effect of pH changes following treatment, on the ability of SRWC to take up large amounts of Cd and other metals. The remediation effect of SRWC was also studied. Under the experimental conditions applied, uptake by SRWC was unaffected by pH changes. The differences between the amounts of metals experimentally applied, less the uptake by SRWC after a potential harvest, were broadly within the permitted limits. For Cd, a reduction of total amounts in soil was observed.

Adsorption↗
PubMed2005

[Clinical results of intestinal and multivisceral transplantation at the Charité, Berlin. A case series].

BACKGROUND AND OBJECTIVE: Intestinal transplantation (ITx) is the only causal therapy of short bowel syndrome (SBS). Long-term survival after ITx has been improved significantly during the last years. The experience with ITx at the Charite, Campus Virchow Klinikum, are described and discussed. PATIENTS AND METHODS: Twelve isolated ITx and one multivisceral transplantation (including stomach, pancreatodudenal complex, small intestine, liver, ascending colon, right kidney, and adrenal gland) were performed. Mean recipient age was 37.7+/-10.6 yrs (median: 35 yrs; range: 27 - 58 yrs; M:F = 8:5). All patients had irreversible SBS (0 - 30 cm residual bowel length; mean: 11.8+/-11.4 cm; median: 13 cm). RESULTS: 6-months and 1-year patient and graft survival were 85 % (11/13) and 77 % (10/13), respectively. Reasons for graft loss and patient death were necrotizing enterocolitis, severe, muromonab-resistent, acute rejection, and graft ischemia due to complex coagulopathy. All other patients had good long-term outcome. They received enteral nutrition at six hours after operation and were persistently off total parenteral nutrition (TPN) by week two after ITx. CONCLUSION: ITx as established in our centre, with 1-year-patient and graft survival rates of 77 %, reflects current international standard. ITx is complementary to conservative and other operative methods of treating SBS. Referral and indication criteria need wider dissemination to prevent life-threatening complications of TPN.

Adolescent↗
PubMed2005

[Endoscopic therapy of acute and chronic pancreatitis].

Endoscopic therapy is valuable for both acute and chronic pancreatitis. Early endoscopic papillotomy appears, in the case of a severe course of acute biliary pancreatitis, to be advantageous. Endoscopic drainage can be considered in cases of acute fluid retention and necrosis as well as subacute, non-healing pancreatitis or cyst development. By acute chronic pancreatitis with strictures or bile duct stones, papillotomy, dilation and stent insertion can lead to an improvement in pain symptoms. An improvement in endo- or exocrine function, however, is not expected. Studies on the endoscopic therapy of pancreatitis are still very limited, and recommendations can usually only be made based on retrospective case series.

Acute Disease↗
PubMed2005

Unintentional childhood poisoning in the Sharon area in Israel: a prospective 5-year study.

OBJECTIVES: To study the epidemiology and risk factors for unintentional exposure to poisoning among the Jewish and the Arab population in the Sharon area in Israel. METHODS: We prospectively evaluated visits to the pediatric emergency department because of unintentional poisoning exposure, at the Meir General Hospital. We collected demographic data, substance exposure data, and the clinical outcome of the poisoning. RESULTS: During the 5 years of the study, 502 children were evaluated for unintentional poisoning, 84% Jewish and 16% Arabs; 88.5% occurred in children younger than 5 years, with a peak incidence at the age of 2 years (39.5%). Medications including hormones, vitamins, and antibiotics were the most common cause of exposure. Most children (95%) had no symptoms or abnormal findings on physical examination (84%), and most (85%) were discharged after several hours of observation. However, children of Arab origin presented with severe clinical manifestations because of a high rate of pesticide poisoning. There was 1 death from organic phosphate poisoning. CONCLUSION: Exposure to poisoning is commonly encountered in children. Pesticides exposure is more common in the Arab community and is usually associated with more severe clinical manifestations. Educational preventive programs are mandatory.

Accidents, Home↗
PubMed2004

Specific detection of Fusarium langsethiae and related species by DGGE and ARMS-PCR of a beta-tubulin (tub1) gene fragment.

Fusarium langsethiae was recently described as a new toxigenic Fusarium species, which morphologically resembles Fusarium poae, but exhibits a mycotoxin pattern related to Fusarium sporotrichioides. To develop tools for early and specific detection of F. langsethiae and distinguishing it from related species of section Sporotrichiella and Discolor (F. poae, F. sporotrichioides, Fusarium kyushuense, Fusarium robustum, Fusarium sambucinum and Fusarium tumidum) sequence variations in their beta-tubulin-encoding (tub1) gene were employed to design two PCR-based methods, denaturing gradient gel electrophoresis (DGGE) and amplification refractory mutation system (ARMS)-PCR. DGGE reliably separated all these strains, even from mixtures and in the presence of DNA from their natural hosts Zea mais, Triticum aestivum and Avena sativa. In addition, a tetraprimer ARMS-PCR, which employs two primer pairs to amplify, respectively, two different fragments of tub1 in a single PCR reaction resulted in rapid differentiation between F. langsethiae, F. sporotrichioides and F. poae according to the number of amplicons (four, two and one, respectively). These two methods will thus be worthwhile tools in the specific detection of F. langsethiae in infected crops.

Base Sequence↗
PubMed2004

An integrated taxonomic study of Fusarium langsethiae, Fusarium poae and Fusarium sporotrichioides based on the use of composite datasets.

An integrated systematic study was carried out to clarify the taxonomical position and relationship of Fusarium langsethiae to other taxa within the Fusarium section Sporotrichiella. Strains of this species were compared with strains of the closely related species Fusarium poae and Fusarium sporotrichioides using a composite dataset. This set consisted of DNA sequences derived from the ribosomal internal transcribed spacer (ITS) regions, partial sequences of the ribosomal intergenic spacer (IGS) region, the beta-tubulin and translation elongation factor-1 alpha (EF-1alpha) genes, AFLP fingerprints, chromatographic data on secondary metabolites and morphological data and growth characteristics. From these combined data, a consensus matrix was calculated by taking the mean of all pairwise distances between single isolates over all separate datasets. The consensus matrix was used as the basis for the construction of a UPGMA dendrogram and a multidimensional scaling, both of which revealed a clear separation of the three taxa. Partial IGS, EF-1alpha and beta-tubulin sequence-as well as chromatography-and AFLP-derived similarities turned out to be comparably consistent, while ITS sequence- and morphology-derived similarity matrices were rather divergent.

Base Sequence↗
PubMed2004

Aspirin treatment for neonatal infectious endocarditis.

We describe a term female neonate with Serratia marcescens endocarditis. Despite adequate antibiotic therapy for 8 days, the bacteremia persisted and there was an increase in vegetation size. Treatment with aspirin was initiated, with resolution of the bacteremia and a gradual decrease in vegetation size. We conclude that in neonatal endocarditis, aspirin may be beneficial additional treatment.

Anti-Bacterial Agents↗
PubMed2004

Quantification of Fusarium graminearum in infected wheat by species specific real-time PCR applying a TaqMan Probe.

A new real-time PCR based method was developed for the species-specific detection, identification and quantification of Fusarium graminearum in planta. It utilizes a TaqMan hybridisation probe targeting the beta-tubulin gene and a plasmid standard. The assay is highly specific giving no product with DNA of closely related species. It is very sensitive, detecting down to five gene copies per reaction, and is able to produce reliable quantitative data over a range of six orders of magnitude.

DNA, Fungal↗
PubMed2004

Clinical relevance of transabdominal ultrasonography and magnetic resonance imaging in patients with inflammatory bowel disease of the terminal ileum and large bowel.

BACKGROUND: Ileocolonoscopy represents the diagnostic standard in the work-up of patients with inflammatory bowel diseases (IBD). Patients are often reluctant to be colonoscoped because of the invasiveness and pain sensation during colonoscopy. AIMS: To compare the usefulness oftransabdominal ultrasound (US) and magnetic resonance imaging (MRI) in assessing disease extension and activity in patients with IBD restricted to the terminal ileum and large bowel. PATIENTS AND METHODS: 61 patients with IBD [37 Crohn's disease (CD) and 24 ulcerative colitis (UC)] were prospectively studied. All patients underwent clinical and laboratory assessment, ileocolonoscopy, transabdominal sonography, and MRI within 5 days. Involved bowel segments were defined as those with bowel wall thickness >3 mm and increased Doppler signal on US or contrast enhancement of the bowel wall on MRI. To compare disease activity endoscopic, MRI and US findings were graded with newly developed scores. RESULTS: The segment-by-segment analysis revealed an overall accuracy of 89% for US and 73% for MRI in identifying active IBD. The accuracy was better in patients with UC than in patients with CD for both US and MRI. The endoscopic activity index (EAI) correlated stronger with the US activity index (r = 0.884) than with the MRI activity index (r = 0.344). The correlation of US and MRI activity indices with EAI was better in patients with UC compared with patients with CD. All three imaging methods showed a significant correlation with clinical disease activity in patients with UC but not in patients with CD. CONCLUSION: This study provides strong evidence that US should be considered as a first-choice method for follow-up of patients with IBD of the terminal ileum and large bowel.

Adult↗
PubMed2003

Ovarian hormone influences on the density of immunoreactivity for tyrosine hydroxylase and serotonin in the primate corpus striatum.

The serotonergic and dopaminergic inputs to the corpus striatum in human and non-human primates participate in diverse sensorimotor, cognitive, and affective functions, are implicated in dysfunction in diseases such as Parkinson's disease and schizophrenia, and are targets for many of the drugs used to treat these disorders. Sex differences in the incidence and/or clinical course of these disorders and in the effectiveness of related dopaminergic and serotonergic drug therapies suggest that primate striatal indolamines and catecholamines are also influenced by gonadal hormones. However, while well studied in rats, relatively little is known about precisely how gonadal steroids modulate stratial dopamine and serotonin systems in primates. To begin to address this issue, the present studies explored the effects of ovarian steroids on the serotonergic and dopaminergic innervation densities of the caudate, putamen, and the nucleus accumbens in young adult rhesus monkeys. Using densitometry to quantify immunoreactivity for serotonin and for the catecholamine-synthesizing enzyme tyrosine hydroxylase, innervation densities were compared in identified, functionally specialized striatal subdomains across animals that were either ovariectomized or ovariectomized and supplemented with estradiol and/or progesterone, i.e. in a primate model of surgical menopause, with and without hormone replacement therapy. These analyses revealed clear examples of structure-, hemisphere-, and replacement regimen-specific effects of changes in circulating steroids on the densities of each afferent system examined. Further, the predominantly stimulatory effects observed occurred in striatal areas analogous to those suspected as sites of localized dopamine and/or serotonin compromise in Parkinson's disease and schizophrenia. Thus, the hormone actions identified in this study could hold relevance for some of the sex differences identified in relation to these disorders, including the findings of decreased incidence and/or symptom severity in women that have led to hypotheses of protective effects for estrogen.

Animals↗
PubMed2003

[Management of bile duct injuries following laparoscopic cholecystectomy].

INTRODUCTION: The aim of the present study is to analyse our experience in the treatment of bile duct injury following laparoscopic cholecystectomy and to propose an algorithm for the management. PATIENTS AND METHODS: From January 1990 to March 2002 175 patients with biliary tract injury sustained during laparoscopic cholecystectomy were treated at our institution. We divided the injuries into five basic types according to the mechanism, localisation and time of manifestation of the lesion. Risk factors affecting the outcome after operative repair were analysed by uni- and multivariate analysis. RESULTS: There were 46 patients with peripheral bile leak (Type A). Endoscopic treatment was successful in 92 %. 8 patients presented with an occlusion of the common bile duct (CBD) (Type B). Five of 6 patients with an incomplete occlusion of the CBD could be treated by endoscopic options. Of 52 patients that presented a lateral lesion of the CBD (Type C), endoscopic treatment was successful in 35 patients (67 %), but surgical treatment was necessary in 17 (33 %). 27 patients with a complete transsection of the CBD required surgical reconstruction. Endoscopic treatment was successful in 34 of 42 patients with a late stenosis of the CBD. 11 of 55 patients (20 %) developed postoperative biliary complications. Univariate analysis identified three factors to be significant predictors of outcome: 1. attempts of repair before referral, 2. combined bile duct and hepatic artery injury, 3. Reconstruction in a situation of peritonitis. After a median follow-up of 44.6 months (2-109) a successful outcome was obtained in 51 of 55 (93 %) patients, including those requiring a secondary procedure for recurrent stricture. CONCLUSIONS: Peripheral leakages, small lateral lesions and short stenosis usually can be treated endoscopically. Extended lateral injuries, complete CBD transsections and long stenoses require surgical therapy. For a successful therapy a specialized multidisciplinary team is crucial.

Algorithms↗
PubMed2002

Obesity and target organ damage: diabetes.

Obesity is an important risk factor for the development of type 2 diabetes. The increasing incidence of obesity accounts in large part for the emergence of type 2 diabetes. Drug treatment of hyperglycaemia and hypertension lowers the risk of diabetic complications, but many of these treatments, including sulphonylureas, insulin and beta-blockers, are associated with weight gain. There is increasing evidence that obesity may be an independent risk factor for complications in both type 2 and type 1 diabetes. Therapies to lower body weight will undoubtedly have a role in the treatment of diabetes to potentially avert weight gain associated with anti-diabetic therapies, to lower glycaemia, and possibly even to lower the risk of diabetic complications. However, many questions remain to be answered.

Adult↗