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.

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.

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.

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.

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.

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.

[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.

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.

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.

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.

Healing practices: trends, challenges, and opportunities for nurses in acute and critical care

Florence Nightingale espoused a very holistic orientation in nursing. It was her belief that nursing should put the patient in the best possible condition for nature to restore or preserve health, to prevent or cure disease or injury. In other words, nurses should create environments in which healing can happen. Complementary therapies and healing practices offer nurses and patients an expanded array of options to improve health and healing. This article provides an overview of complementary therapies and healing practices and offers suggestions on how to incorporate these therapies when caring for critically ill patients.

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.

[Gamma-hydroxybutyrate, a new central nervous system stimulant]

In the last months we have seen an increasing number of younger patients admitted to the emergency room in a deep coma, mostly without cardio-pulmonary symptoms. After a few hours they suddenly woke up without any after-effects. Subsequently the patients related that they had taken an unknown drug for recreational purposes and afterwards fell asleep. The patients did not remember anything else about the episode. We believe they had taken gammahydroxybutyrate (GHB). This drug has not previously been described in Danish scientific reports.

[Interferon therapy of multiple sclerosis]

The use of beta-interferon in the relapsing-remitting phase of multiple sclerosis is a new though fairly established therapy. The beneficial effect of this treatment is thought to be due to immune modulation, with inhibitory action on proliferation of leukocytes and antigen presentation, an increased amount of interleukins, but no change in the proinflammatory cytokine interferon-gamma. In Norway, one interferon-beta 1b and two interferon-beta 1a products have recently been introduced for administration by either subcutaneous or intramuscular injection. Approximately 30% reduction in the relapse rate is reported for both products,but differences appear in the effect on the disability progression, and also with regard to adverse reactions. Patients less strongly affected by the illness seem to have the best outcome. Neutralizing antibodies are often produced during this treatment, but the significance of this is still unclear. Results from international studies on interferon therapy of multiple sclerosis are discussed. Initial results from studies on interferon treatment of secondary progressive multiple sclerosis are now available. A further expansion, also in Norway, of the indications for beta-interferon therapy of multiple sclerosis is expected in the near future.

Determination of sodium and ammonium ions in disproportionate concentration ratios by ion chromatography

In ion chromatography, samples of very different ammonium-to-sodium concentration ratios are difficult to quantify since these two cations have similar selectivities for stationary phases containing commonly used sulfonate or carboxylate cation-exchange functional groups. The IonPac CS15 cation-exchange column, with carboxylate and phosphonate functional groups as well as a crown ether group, was developed to address this limitation. Selectivity for the common inorganic cations on this column is different from that of conventional cation-exchange columns in that the separation between sodium and ammonium ions has been greatly increased, allowing for determinations of low levels of one in the presence of high levels of the other with an isocratic eluent. For larger than 4000:1 sodium-to-ammonium concentration ratios, an eluent step change or gradient elution is needed. For moderate ratios, combinations of this column with a carboxylate column, containing no crown ether group, can be used at room temperature with an isocratic eluent containing no organic solvent.

Interferon-alpha2a reduces MRI disease activity in relapsing-remitting multiple sclerosis. Norwegian Study Group on Interferon-alpha in Multiple Sclerosis

OBJECTIVE

To evaluate the efficacy and safety of interferon-alpha2a (IFN-alpha2a) in relapsing-remitting MS (RRMS).

BACKGROUND

Several immune-modulating therapy regimens of IFN-alpha have shown varying results in MS. A recent pilot study suggested benefits from IFN-alpha2a.

METHODS

Ninety-seven patients were randomized to receive subcutaneous injections of placebo (33 patients) or 4.5 million international units (mIU) (32 patients) or 9.0 mIU (32 patients) of IFN-alpha2a three times weekly for 6 months, with a further 6 months of follow-up. Monthly gadodiamide-enhanced MRI was the primary method of evaluating efficacy.

RESULTS

IFN-alpha2a treatment resulted in fewer new MRI lesions during the treatment period (p < 0.003). The probability of no new lesions during treatment was >2.5 times higher with 9.0 mIU IFN-alpha2a than with placebo (p < 0.005). The median number of lesions at the end of treatment was lower with IFN-alpha2a treatment than with placebo (p = 0.0004), but the difference disappeared during follow-up. The total number of lesions (mean) increased by 4.78 with placebo, 0.86 with 4.5 mIU IFN-alpha2a, and 0.28 with 9.0 mIU IFN-alpha2a during treatment (p = 0.030). No treatment effect on exacerbation rate, progression of disability, or quality of life was detected. Nine patients discontinued treatment, five because of adverse events.

CONCLUSIONS

IFN-alpha2a treatment significantly reduced disease activity as measured by MRI, but the efficacy disappeared within 6 months after discontinuation of treatment. A long-term study of more patients using disability as a primary outcome measure is needed to evaluate the clinical impact.

[Guillain-Barre syndrome. Current treatment principles in the light of clinical aspects]

The Guillain-Barré's syndrome, or acute polyradiculoneuropathy, is a monophasic neurological disease affecting 50-100 persons a year in Norway. In addition to peripheral paresis, respiratory and autonomic disturbances may occur. We present 22 patients, mean age 34.8 years, including four children between four and six years of age, who all received plasma exchange treatment. All our patients reported symptoms of a modest infection average 19 days before the neurological symptoms appeared. All patients had walking difficulties, half of them were unable to walk without assistance. There were cranial nerve findings in 18 patients, and nine had autonomic disturbances when admitted. All except one had increased protein contents in the spinal fluid as well as pathological findings in electrophysiological investigations. They received on average 8.6 plasma exchanges. In spite of such treatment, the total mortality rate has not decreased substantially. Two of our patients died, and three developed severe permanent paresis. Further studies on pathogenesis will be required to increase treatment success.

Growth/cell cycle regulation of Sp1 phosphorylation

Sp1 sites can mediate growth/cell cycle induction of dihydrofolate reductase in late G1 (Jensen, D. E., Black, A. R. Swick, A. G., and Azizkhan, J. C. (1997) J. Cell. Biochem. 67, 24-31). To investigate mechanisms underlying this induction, effects of serum stimulation on regulation of Sp1 were examined. In Balb/c 3T3 cells, serum stimulation did not affect Sp1 synthesis or the relative binding of Sp1 family members to DNA; however, it did result in a rapid, approximately 2-fold increase in Sp1 levels and an approximately 3-fold increase in specific Sp1 phosphorylation in mid-G1. In normal human diploid fibroblasts, serum stimulation also increased Sp1 phosphorylation in mid-G1 but did not affect Sp1 levels. Therefore, Sp1 phosphorylation is regulated in a growth/cell cycle-dependent manner which correlates temporally with induction of dihydrofolate reductase transcription. Further studies revealed a kinase activity specifically associated with Sp1 in a growth-regulated manner. This activity is distinct from purified kinases previously shown to phosphorylate Sp1 in vitro and phosphorylates Sp1 between amino acids 612 and 678 in its C terminus, a region also phosphorylated in mid-G1 in vivo. Therefore, this study indicates that phosphorylation of the C terminus of Sp1 may play a role in the cell cycle regulation of its transcriptional activity.

Mechanisms of cardioprotection by peroxynitrite in myocardial ischemia and reperfusion injury

Peroxynitrite (ONOO-), an intermediate formed from the equimolar interaction of nitric oxide (NO) and superoxide, is thought to be an important mediator of tissue injury in myocardial ischemia-reperfusion. However, physiologically relevant (i.e., maximally achievable) concentrations of ONOO- significantly decreased neutrophil-endothelium interactions in the rat mesentery. We therefore examined the dose-response relationship of infusion of different concentrations of ONOO- in a feline model of myocardial ischemia-reperfusion and provide data on the cellular mechanisms responsible for these observed effects. Cats subjected to 90 min of ischemia followed by 270 min of reperfusion were infused with different concentrations of ONOO- 10 min before reperfusion and continuing throughout reperfusion. We observed that infusion of 2 microM ONOO- provided significant cardioprotection, whereas either 0.2 or 20 microM ONOO- did not protect. ONOO- at 2 microM also preserved coronary endothelial function, decreased P-selectin expression, and attenuated polymorphonuclear leukocyte (PMN) adherence to the vascular endothelium. ONOO- did not exert its cardioprotective effects by acting as a direct NO donor in solution. However, in vitro, ONOO- can react with glutathione to form S-nitrosoglutathione, which can act as an NO carrier and exert beneficial effects. Thus only maximally achievable concentrations of ONOO- exert significant cardioprotective effects, in part by decreasing surface expression of P-selectin and decreasing PMN-endothelium interactions.

Simultaneous detection of high energy phosphates and metabolites of glycolysis and the Krebs cycle by HPLC

For the detailed analysis of energy metabolism, a HPLC method is described allowing the single-run separation and quantification of most metabolites from glycolysis and the Krebs cycle including the high energy phosphates. With a detection limit in the picomolar range this method is even applicable when only small sample sizes of tissue are obtained.

Roles of DnaK and RpoS in starvation-induced thermotolerance of Escherichia coli

DnaK is essential for starvation-induced resistance to heat, oxidation, and reductive division in Escherichia coli. Studies reported here indicate that DnaK is also required for starvation-induced osmotolerance, catalase activity, and the production of the RpoS-controlled Dps (PexB) protein. Because these dnaK mutant phenotypes closely resemble those of rpoS (sigma38) mutants, the relationship between DnaK and RpoS was evaluated directly during growth and starvation at 30 degrees C in strains with genetically altered DnaK content. A starvation-specific effect of DnaK on RpoS abundance was observed. During carbon starvation, DnaK deficiency reduced RpoS levels threefold, while DnaK excess increased RpoS levels nearly twofold. Complementation of the dnaK mutation restored starvation-induced RpoS levels to normal. RpoS deficiency had no effect on the cellular concentration of DnaK, revealing an epistatic relationship between DnaK and RpoS. Protein half-life studies conducted at the onset of starvation indicate that DnaK deficiency significantly destabilized RpoS. RpoH (sigma32) suppressors of the dnaK mutant with restored levels of RpoS and dnaK rpoS double mutants were used to show that DnaK plays both an independent and an RpoS-dependent role in starvation-induced thermotolerance. The results suggest that DnaK coordinates sigma factor levels in glucose-starved E. coli.