Biomedical subjects

D Jensen

Publications and source records attributed to D Jensen.

At least 19 recordsLinked to original sources

PubMed2005

Serological markers of autoimmunity in patients infected with hepatitis C virus: impact of HIV co-infection.

OBJECTIVES: We sought to evaluate the prevalence, predictors and significance of autoantibody expression in patients with chronic hepatitis C (CHC) with or without HIV co-infection. METHODS: Retrospective review of laboratory and histologic data for all patients with CHC who had a liver biopsy available. HIV status was documented in all patients. Results analyzed in SPSS10, Chicago, IL, a p value <0.05 was considered significant. RESULTS: 170 patients with hepatitis C viremia, including 107 (63%) HIV co-infection, who had testing for anti-nuclear antibody (ANA) or anti-smooth muscle antibody (ASMA) and anti-mitochondrial antibody (AMA) were included in the study. Overall, 63% (74/117) of patients were ASMA seropositive and 6% (9/153) were positive for ANA. All 117 patients tested for AMA were negative. HIV co-infected patients were significantly more likely to be ASMA positive 71% (53/75) compared to those with hepatitis C alone (50%) [P=0.026]. There were no significant differences in age, gender, race, risk group, alanine aminotransferase (ALT) levels or grade of inflammation on histology between autoantibody positive and negative patients. ASMA positive patients had significantly higher globulin levels (P=0.036) and a trend towards more bridging fibrosis or cirrhosis. Patients with autoantibody expression rarely had histologic features of AIH. CONCLUSION: We found a high rate of ASMA seropositivity in our cohort of patients with chronic hepatitis C, and HIV co-infection was associated with significantly higher rates of ASMA expression. Autoantibody expression was not associated with demographic or clinical characteristics and does not necessarily preclude antiviral therapy.

Adult↗

PubMed2005

IL-10 promoter haplotype influence on interferon treatment response in multiple sclerosis.

The level of interleukin-10 (IL-10) expression is related to polymorphisms -1082 (G/A), -819 (T/C) and -592 (A/C) in the promoter region of the IL-10 gene, which constitute three haplotypes, GCC, ATA, and ACC. The ATA (a non-GCC) haplotype, which is associated with low IL-10 expression, has been shown to improve interferon (IFN) treatment response in hepatitis C. We analysed the distribution of IL-10 promoter haplotype combinations to determine whether they could influence initial IFN treatment response in 63 patients with relapsing-remitting multiple sclerosis (MS). The patients were grouped into non-GCC or GCC haplotypes, and the clinical and magnetic resonance imaging (MRI) disease activity was compared in the two groups. During the first 6 months of treatment, MS patients with non-GCC haplotypes experienced fewer new MRI T1-contrast enhancing lesions [0.77+/-0.36 (SEM)] than patients with the GCC haplotype (2.45+/-0.57) (P=0.05, Mann-Whitney U test). No differences were detected on clinical disease activity. The results suggest an influence of IL-10 promoter polymorphisms on IFN treatment response in MS.

Adult↗

PubMed2004

Doxazosin controlled release vs tamsulosin in the management of benign prostatic hyperplasia: an efficacy analysis.

An analysis is presented to compare the efficacies of the doxazosin gastrointestinal therapeutic system (doxazosin-GITS) and tamsulosin in patients with benign prostatic hyperplasia (BPH), collecting data from a published 20-week, randomized, double-blind, crossover study. Results demonstrated that after 8 weeks of treatment, both doxazosin-GITS and tamsulosin provided significant (p < 0.001) improvement from baseline in total international prostate symptom score (IPSS) and obstructive and irritative subscores. Doxazosin-GITS was more effective than tamsulosin (p = 0.019 between-group difference for total IPSS; p = 0.001 for irritative subscore). Similarly, after the first 4 weeks of treatment, prior to dose titration, both doxazosin-GITS and tamsulosin provided significant (p < or = 0.001) improvement in total IPSS and subscores. Doxazosin-GITS was more effective than tamsulosin (p = 0.045 between-group difference for obstructive subscore). These data confirm that the efficacy of doxazosin is superior to that of tamsulosin in the management of patients with BPH.

Adrenergic alpha-Antagonists↗

PubMed2004

IgA antibodies against gliadin and gluten in multiple sclerosis.

BACKGROUND: Multiple changes in antibodies against various antigens are found in multiple sclerosis (MS). OBJECTIVE: We wanted to measure immunoglobulin A (IgA) antibodies to some common food antigens in MS and also IgG against gliadin and gluten. METHODS: The IgA antibodies were measured in serum against gluten, gliadin, lactoglobulin, lactalbumin, casein and ovalbumin in patients with MS and controls using ELISA technique. IgG was likewise measured for gluten and gliadin. RESULTS: Highly significant increases compared with controls were found for IgA and IgG antibodies against gliadin and gluten. IgA antibodies against casein were significantly increased. Anti-endomycium and anti-transglutaminase antibodies were negative. CONCLUSIONS: The data presented indicate that there may be a possible moderately increased uptake of some specific proteins from the gut in MS compared with controls.

Adult↗

PubMed2003

In vivo cellular uptake of bismuth ions from shotgun pellets.

Shotgun pellets containing bismuth (Bi) are widely used and may cause a rather intense exposure of some wild animals to Bi. A Bi shotgun pellet was implanted intramuscularly in the triceps surae muscle of 18 adult male Wistar rats. Another group of 9 animals had a Bi shotgun pellet implanted intracranially in the neocortex. Eight weeks to 12 months later the release of Bi ions was analysed by autometallography (AMG) of tissue sections from different organs (brain, spinal cord, kidney, liver, testes). In the group with intramuscular Bi shotgun pellets no AMG staining could be found for the first 2-4 months; 6 months after exposure Bi was traced in the kidney. Twelve months after the implantation the kidneys were heavily loaded and Bi was also traced in testosterone-producing Leydig cells, in glial cells and in neurons of brain and spinal cord. In the central nervous system (CNS) motor neurons were the most loaded. In rats with intracranially implanted shotgun pellets a massive uptake of Bi was observed involving both glia and neurons throughout the brain. The cells close to the shotgun pellet had the highest uptake. The animals showed a pronounced Bi uptake in the ependyma cells lining the ventricular system and in the cubic epithelia covering the choroid plexus. Dissemination of Bi ions to the rest of the body was demonstrated by AMG tracing of Bi accumulations in the tubular cells of the kidney. These findings emphasize that metallic Bi, including shotgun pellets, represents sites of intense Bi pollution if implanted or shot into a living organism, and further that such metallic Bi bodies, if they enter the CNS, cause a spread of Bi ions throughout it.

Animals↗

PubMed2002

Modern stationary phases for ion chromatography.

Due to the better understanding of the processes taking place at the surface of the stationary phases, the number of ion-exchange materials for ion chromatography (IC) has increased tremendously over recent years. As a result, the multitude of commercially available columns today with their different selectivities for anion and cation chromatography is almost confusing. Hence, the aim of this article is to describe the different principles determining selectivity and ion-exchange capacity and to classify the various ion-exchange materials accordingly. To ensure a fair comparison of these columns, the selectivity differences are illustrated by showing separations of standards rather than individual samples.

Journal Article↗

PubMed2002

Dynamics of Pleistocene population extinctions in Beringian brown bears.

The climatic and environmental changes associated with the last glaciation (90,000 to 10,000 years before the present; 90 to 10 ka B.P.) are an important example of the effects of global climate change on biological diversity. These effects were particularly marked in Beringia (northeastern Siberia, northwestern North America, and the exposed Bering Strait) during the late Pleistocene. To investigate the evolutionary impact of these events, we studied genetic change in the brown bear, Ursus arctos, in eastern Beringia over the past 60,000 years using DNA preserved in permafrost remains. A marked degree of genetic structure is observed in populations throughout this period despite local extinctions, reinvasions, and potential interspecies competition with the short-faced bear, Arctodus simus. The major phylogeographic changes occurred 35 to 21 ka B.P., before the glacial maximum, and little change is observed after this time. Late Pleistocene histories of mammalian taxa may be more complex than those that might be inferred from the fossil record or contemporary DNA sequences alone.

Animals↗

PubMed2002

Early operation or conservative management of patients with small bowel obstruction?

OBJECTIVE: To evaluate the outcome after initial non-operative treatment in patients with small bowel obstruction (SBO). DESIGN: Prospective study. SETTING: University hospital, Norway. PATIENTS: One hundred and fifty-four patients with 166 episodes of SBO admitted during the period (1994-1995). Patients younger than 10 years as well as patients with large bowel obstruction, paralytic ileus, incarcerated hernia or SBO caused by cancer were excluded from the study. INTERVENTIONS: Patients with signs of strangulation were operated on early. The rest were given a trial of conservative treatment. MAIN OUTCOME MEASURES: Need of operative treatment. Incidence of bowel strangulation, complications and death. RESULTS: There were 166 cases of SBO. Twenty patients were operated on early among whom bowel was strangulated in 9. Among the 146 patients initially treated conservatively 93 (64%) settled without operation, 9 (6%) had strangulated bowel and 3 (2%) died. Of the 91 patients with partial obstruction but no sign of strangulation, 72 (79%) resolved on conservative treatment. CONCLUSIONS: Patients with partial obstruction with no sign of strangulation should initially be treated conservatively. When complete obstruction is present, it may settle on conservative management, but the use of supplementary diagnostic tools might be desirable to find the patients who will need early operative treatment.

Adolescent↗

PubMed2001

Degradation of 4-nonylphenol in homogeneous and nonhomogeneous mixtures of soil and sewage sludge.

Sewage sludge is frequently applied as fertilizers to cultivated land. However, municipal sewage sludge often contains organic contaminants including nonylphenol (NP), an intermediate from nonionic surfactant degradation. Knowledge about NP degradation in sludge-amended soil is an important prerequisite for adequate risk assessments. In this study, mineralization of 14C-labeled NP in homogenized and nonhomogenized sludge-soil mixtures was investigated. NP was degraded within 38 days in aerobic homogenized mixtures. In nonhomogeneous mixtures containing sludge aggregates, the degradation of NP was retarded and was generally not completed within 3 months (119-126 days). No detectable amounts of NP were transported from the sludge aggregates to the surrounding soil (detection limit: <0.04 mg of NP/kg dw of soil). Oxygen penetration into sludge aggregates was monitored for 50 days with an oxygen microelectrode. An extrapolation of the oxygen data suggested that more than 1 year was required to obtain fully aerobic conditions in a 2-cm sludge aggregate. Since NP is considered persistent in the absence of oxygen, residual amounts of NP may be present in the anaerobic center of aggregates for prolonged periods. The results demonstrate that sludge aggregate size and thus oxygen availability will be a major controlling factor for NP degradation in soil amended with sewage sludge and that the mobility of NP from sludge aggregates to the surrounding soil is negligible.

Agriculture↗

PubMed2001

Simplified in-line sample preparation for amino acid analysis in carbohydrate containing samples.

This report describes a new, automated chromatographic procedure eliminating carbohydrates from amino acid samples prior to their analysis by anion-exchange chromatography and integrated amperometric detection. In the first step, a sample is brought onto a short cation-exchange column (trap column) in hydrogen form. Carbohydrates are passing through this column, while only amino acids are retained. Subsequently, the cation-exchange column, holding the amino acid fraction, is switched in-line with the gradient pump and separator column. The mobile phase used at the beginning of the separation (NaOH; pH 12.7) transfers amino acids from the trap column onto the anion-exchange column and the amino acid separation is completed without any interference by carbohydrates. All common amino acids are recovered following the carbohydrate removal step. The average value of their recovery is 88.1%. The calibration plots were tested between 12.5 and 500 pmol (amounts injected). The mean value of correlation coefficients of calibration plots was calculated as 0.99. The mean value of relative standard deviations from five replicates was 3.9%. The usefulness of the method is illustrated with two chromatograms of a carrot juice sample obtained before and after the in-line removal of carbohydrates.

Amino Acids↗

PubMed2001

Determination of trace anions in high-nitrate matrices by ion chromatography.

An ion chromatography method was developed to determine trace anionic contamination in matrices that have a high concentration of nitrate ion. Contaminant anions of interest were separated on an IonPac AS15 high-capacity anion-exchange column and detected by suppressed conductivity detection. An EG40 eluent generator was used to prepare high-purity and carbonate-free potassium hydroxide. Using the EG40, performance at trace levels was enhanced because background conductivity decreased and retention time reproducibility improved. Trace anionic contamination from the mobile phase was minimized when using the eluent generator compared to using conventionally prepared sodium hydroxide eluents. The signal-to-noise ratio was also improved with the use of a temperature controlled conductivity cell and chromatography hardware in the microbore (2-mm) format. The eluent concentration was optimized to separate the contaminant anions from the excess of the nitrate matrix ions. The procedure was demonstrated for a solution of reagent-grade sodium nitrate and high-purity 0.7% nitric acid. Method detection limits for chloride, sulfate and phosphate of 150 microg/l and lower were achieved.

Anions↗

PubMed2001

[Acute renal failure, renal artery stenosis and angiotensin-converting enzyme (ACE) inhibitor].

BACKGROUND: Acute renal failure is a well-known complication in patients with renal artery stenosis during treatment with ACE inhibitor. Renal artery thrombosis after withdrawal of ACE inhibitor has not been reported previously. MATERIAL AND METHODS: We describe a patient with acute renal failure with an unexpected course. RESULTS: A 67-year-old man was admitted with acute anuric renal failure during treatment with hydrochlorothiazide and enalapril. His blood pressure was 165/60 mm Hg. Renal ultrasound was normal. After initial rehydration and dialysis, diuresis resumed until a sudden unexpected anuric renal failure recurred on day 12. Angiography disclosed bilateral renal artery occlusion. The right renal artery was successfully opened and a stenosis was blocked and stented, and brisk diuresis ensued. Two days later hypertension accelerated, and a new invasive procedure on day 24 succeeded in opening, blocking and stenting a proximal stenosis in the left artery; a mobile thrombus was located behind the stenosis and successfully treated with intraarterial thrombolysis. Blood pressure rapidly normalized, and serum creatinine was normal on visits 1.5 and 4 months later. INTERPRETATION: General aspects and prevention of acute renal failure during ACE inhibitor therapy are discussed. Acute renal thrombosis after withdrawal of ACE inhibitor in patients with stimulated renin angiotensin system and significant renal artery stenosis may be causally related to the antifibrinolytic effects of angiotensin II and aldosterone. Endovascular reconstruction of renal artery occlusion may completely restore the kidney function.

Acute Kidney Injury↗

PubMed2001

Cholangiocytic apoptosis in chronic ductopenic rejection.

The significance of cholangiocytic apoptosis as a mechanism of ductopenia in liver rejection remains controversial. In a previous study, the presence but not the extent of ductal apoptosis was assessed by electron microscopy. Other previously published studies using an in situ hybridization method (in situ end labeling) produced conflicting results (no apoptosis v massive apoptosis). We studied 47 liver needle biopsies from 8 patients with chronic ductopenic rejection confirmed by pathologic examination of the failed grafts. These biopsies were performed because of graft dysfunction, during a period of several months before retransplantation, and they showed cholangiocytic injury with progressive ductal paucity. Terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick-end labeling (TUNEL) was used to detect apoptosis (tissue digestion with proteinase K 20 microg/mL for 20 minutes). The interlobular bile ducts did not show labeling, even in lymphocytic cholangitis with obvious epithelial injury. However, there was minimal staining of ductular nuclei. Lymphocytic nuclei were also labeled. Apoptosis was not detectable in the vanishing interlobular bile ducts, even when more representative samples were studied and a more sensitive method was used. Unless apoptosis of cholangiocytes is an exceptionally rapid process escaping detection by conventional methods, ductopenia results mainly from ordinary, nonprogrammed cholangiocytic death. Apoptosis could still be involved in the pathogenesis of ductopenia by depleting cholangiocytic precursors, generally presumed to reside in ductules. This is a possible mechanism suggested by the following: (1) the established role of apoptosis in the homeostatic control of immature/progenitor cells, (2) the paucity of ductular proliferation in chronic rejection, (3) the previously reported decrease of ductular bcl-2 expression in rejection, and (4) the sporadic ductular TUNEL labeling seen in this study.

Apoptosis↗

PubMed2001

Efficacy and safety of pegylated (40-kd) interferon alpha-2a compared with interferon alpha-2a in noncirrhotic patients with chronic hepatitis C.

Administration of interferon (IFN) 3 times weekly in patients with chronic hepatitis C (CHC) is associated with low sustained responses, which may be, in part, related to this regimen's inability to maintain IFN concentrations sufficient to suppress viral replication. An enhanced IFN molecule produced by the covalent attachment of a branched 40-kd polyethylene glycol moiety to IFN alpha-2a (PEG[40kd] IFN alpha-2a) exhibits sustained absorption, a restricted volume of distribution, and reduced clearance compared with unmodified IFN alpha-2a. One hundred fifty-nine patients with CHC participated in a randomized, ascending-dose (45 or 90, 180, 270 microg) study comparing PEG(40kd) IFN alpha-2a administered once weekly with 3 MIU IFN alpha-2a administered 3 times weekly for 48 weeks to determine the most appropriate PEG(40kd) IFN alpha-2a dose for subsequent clinical trials. Efficacy was assessed by measuring hepatitis C virus (HCV) RNA following a 24-week treatment-free period. Sustained virological responses for PEG(40kd) IFN alpha-2a once weekly were 10% (45 microg; not significant), 30% (90 microg; P = .009), 36% (180 microg; P = .0006), and 29% (270 microg; P = .004), compared with 3% for the 3-times-weekly 3-MIU IFN alpha-2a regimen. The types and frequencies of adverse events and laboratory abnormalities were similar among all groups. In conclusion, once-weekly PEG(40kd) IFN alpha-2a was associated with a higher number of sustained virological responses compared with IFN alpha-2a 3 times weekly in patients with CHC, but had a similar safety profile. The 180-microg PEG(40kd) IFN alpha-2a dose appeared to be the optimal dose based on sustained virological response and its associated side-effect profile.

Adult↗

PubMed2001

Liver transplantation in patients with hepatitis B virus infection: outcome in Asian versus white patients.

Previous studies have found that Asian patients transplanted for hepatitis B virus (HBV) infection had worse outcomes than white patients. The aim of this study was to compare outcomes in Asian and white patients listed for liver transplantation for HBV infection. Data of all patients with HBV infection listed for liver transplantation between January 1996 and June 1998 from 20 centers in North America were collected using a survey. Total patients enrolled were 325 (171 whites, 126 Asians, 28 other races). There was no difference in demographics, liver biochemistry, and HBV replicative status between Asians and whites at the time of listing. More Asians had hepatocellular carcinoma and fewer Asians had hepatitis C or D virus coinfection. At the time of this survey, 70 Asians (55%) and 99 whites (58%) had been transplanted. Actuarial 2-year survival posttransplantation for Asians (88%) and whites (92%) was similar. Recurrent HBV infection occurred in 8 (11%) Asians and 12 (12%) whites. Five patients with recurrent HBV infection died, 4 of whom were Asian. Actuarial 2-year survival for Asians versus whites with recurrent HBV infection was 60% versus 90% (P =.04). In this large cohort of patients, overall survival and recurrent HBV infection posttransplantation were comparable between Asians and whites. However, Asians with recurrent HBV infection posttransplantation had significantly higher mortality.

Antiviral Agents↗

PubMed2000

New technique for increasing retention of arginine on an anion-exchange column.

A method is described for enhancing retention of arginine on a pellicular anion-exchange column. Arginine exhibits adjustable increases of retention time that are dependent on the acidity of standard or sample matrix. This effect is based on interactions of the protonated form of arginine with the residual cation-exchange groups on the core beads of pellicular particles. The relative magnitude of retention time shift of arginine is evaluated for identical concentrations of hydrochloric, sulfuric, and perchloric acids. Although the direct addition of acid is very effective in influencing the retention of arginine, it affects peak shapes and retention of other peaks in the chromatographic separation. The new technique-acid coinjection-achieves a similar retention enhancement for arginine with only a minimal effect on the rest of the separation. Detection limits, reproducibility results, and calibration data are presented for the chromatography of amino acids with acid coinjection. Improved resolution of arginine is demonstrated with chromatograms of soybean hydrolysate and cell culture samples.

Arginine↗

PubMed2000

Determination of aldehydes in food by high-performance liquid chromatography with biosensor coupling and micromembrane suppressors.

A high-performance liquid chromatography system for the determination of aldehydes in food was developed incorporating an Cation MicroMembrane Suppressor (CMMS) and enzyme reactors packed with VA-Epoxy on which aldehyde dehydrogenase from bakers yeast and NADH oxidase from Bacillus licheniformis were immobilized. The method was based on the principle that the separation efficiency of HPLC is combined with the sensitivity of electrochemical detection and the specificity of enzymes. Main attention was directed to the determination of 5-hydroxymethyl-2-furaldehyde and 2-furaldehyde, the occurrence of which is an indication of quality deterioration in several food products. The efficiency of the method has been shown by the analysis of honey, coffee and related beverages, refreshments, sherry, port, dry fruits and breakfast cereals.

Aldehydes↗

PubMed2000

Upper gastrointestinal contrast study in the management of small bowel obstruction--a prospective randomised study.

OBJECTIVE: To find out whether contrast radiography helps to resolve small bowel obstruction. DESIGN: Prospective randomised trial. SETTING: University hospital, Norway. SUBJECTS: 98 consecutive patients with symptoms of small bowel obstruction and a plain abdominal radiograph that confirmed the diagnosis. INTERVENTIONS: The patients were randomly allocated to receive a mixture of barium and sodium diatrizoate (Gastrografin) (n = 48) or not (n = 50). Both groups were followed up clinically and by repeated abdominal films. MAIN OUTCOME MEASURES: Non-operative resolution of small bowel obstruction; number of patients with strangulated bowel; bowel resections; mortality; complications; hospital stay; and time from admission to operation. RESULTS: No significant differences were observed between the groups in the incidence of non-operative resolution (31/48 in contrast group, 35/50 in control group, OR: 0.89), strangulation obstruction (1/48 in contrast group, 4/50 in control group, OR: 0.24), bowel resection (3/48 in contrast group, 4/50 in control group, OR: 0.76), complications (8/48 in contrast group, 5/50 in control group, OR: 1.80), mortality (3/48 in contrast group, 1/50 in control group, OR: 3.26), and hospital stay (0-7 days: 34/48 in contrast group, 38/50 in control group, p = 0.95). The contrast group had a shorter interval between admission and operation than the control group (0-24 hours: 12/48 in contrast group, 3/50 in control group, p = 0.005). CONCLUSION: The contrast examination did not contribute to the resolution of small bowel obstruction.

Adult↗