Ultrasensitive analysis of the intestinal absorption and compartmentalization of aluminium in uraemic rats: a 26Al tracer study employing accelerator mass spectrometry

BACKGROUND: Developments in accelerator mass spectrometry (AMS) now permit the determination of femtogram amounts of 26Al in blood and in various tissues with good precision and free of external contamination. METHODS: In the present study we used trace quantities of 26Al to investigate the intestinal absorption and compartmentalization of aluminium in rats with renal failure (Nx, 5/6 nephrectomy) and in pair- fed controls (C). Single oral doses of 20 ng 26Al were administered to six animals in each group and, subsequently, 24-h post-load 26Al was analysed in serum, urine, bone, liver, and spleen by means of AMS. RESULTS: Serum concentrations of 26Al were significantly lower in uraemic rats compared to controls, whereas urinary excretion was comparable (Nx, 7.11 +/- 5.78 pg/day vs C, 9.46 +/- 6.10 pg/day), suggesting a higher fraction of ultrafiltrable serum 26Al in uraemia. The target tissues of cellular transferrin-mediated 26Al uptake, liver and spleen, tended to show a larger degree of aluminium accumulation in controls (0.26 +/- 0.31 pg/g vs Nx, 0.14 +/- 0.10 pg/g and 0.37 +/- 0.27 pg/g vs Nx, 0.25 +/- 0.27 pg/g respectively). In contrast, in bone, a site of extracellular aluminium deposition, 26Al concentrations were more elevated in uraemia (1.22 +/- 0.59 pg/g vs C: 0.68 +/- 0.30 pg/g). Estimated total 26Al accumulation in all measured target tissues was significantly higher in uraemic rats (28.15 +/- 9.90 pg vs C: 17.03 +/- 7.03 pg) and total recovery of 26Al from tissue and urine was 26.58 +/- 6.74 pg in controls and 35.75 +/- 7.03 pg in uraemic animals, suggesting a fractional absorption of 0.133% and 0.175% respectively. CONCLUSIONS: Our data suggest that fractional absorption from a dietary level dose of 26Al is about 0.13%. Compartmentalization occurs in transferrin-dependent target tissues such as liver and spleen; however, in quantitative terms extracellular deposition in bone is more important. Uraemia has a significant effect on the intestinal absorption and compartmentalization of aluminium. It enhances fractional absorption and increases subsequent extracellular deposition of aluminium in bone. However, at the same time uraemia does not increase transferrin-dependent cellular accumulation of aluminium in liver and spleen.      

Diagnosing herpesvirus infections by real-time amplification and rapid culture

Procedures using real-time technique were developed to demonstrate the presence of herpes simplex virus type 1 (HSV-1) and HSV-2, varicella zoster virus (VZV), and cytomegalovirus (CMV) in miscellaneous clinical specimens. The assays were compared to rapid culture using centrifugation followed by detection with monoclonal antibodies. A total of 711 consecutive samples were collected from different patient groups. Throat swabs were obtained from transplant patients; dermal or oral specimens were collected from patients suspected for VZV or HSV infection. Genital specimens were taken from patients who attended the Clinic for Sexually Transmitted Diseases at the Dijkzigt Hospital Rotterdam presenting with symptoms of a primary genital ulcer. Nucleic acid extraction was carried out using a MagnaPure LC instrument. The amplification steps were performed on the ABI Prism 7700 sequence detection system. To monitor the process of extraction and amplification, a universal control consisting of seal herpesvirus type 1 (PhHV-1) was added to the clinical specimens. By culture 127 of 668 (19%) samples were positive for HSV-1, 72 of 668 (10.8%) specimens were positive for HSV-2, and 17 of 366 (4.6%) were positive for VZV. Using real-time amplification the numbers of positive specimens were 143 of 668 (21.4%), 97 of 668 (14.5%), and 27 of 366 (7.4%), respectively. Eighty-six specimens were tested for CMV, 12 (14.0%) were positive by culture, and 17 (19.8%) were positive by real-time PCR. The clinical data of the patients with discrepant results were reviewed thoroughly. In all cases the patients with only real-time PCR-positive results could be considered as truly infected. We concluded that the real-time amplification technique is suitable for the detection of human herpesvirus infection. It offers a semiquantitative and reliable assay with a quick result that is more sensitive than rapid culture, especially for the diagnosis of HSV-2 and VZV infections.     

Improved performance of PACE 2 with modified collection system in combination with probe competition assay for detection of Chlamydia trachomatis in urethral specimens from males.

The Gen-Probe PACE 2 assay (GP) in combination with a modified collection system was compared with cell culture (CC) for the detection of Chlamydia trachomatis in urethral specimens from males. Analysis of discordant results was performed by PCR. The modifications, i.e., application of a more rigid swab type and a 50% reduction in the amount of transport medium, were made to improve the sensitivity of the assay. By using the modified GP on 302 urethral specimens from males, a sensitivity of 89.5% and a specificity of 100% were determined. In addition, performance of a probe competition assay on all GP samples with a result > 0.6 and < 1.0 times the cutoff factor (gray zone) detected three more true-positive samples. The sensitivity of GP in combination with the probe competition assay increased to 94.9%, with a specificity of 100%. This was identical to the performance of CC. The modified GP offers a very sensitive and specific alternative to CC.     

Long term response to interferon treatment in chronic hepatitis C patients is associated with a significant reduction in anti-E1 envelope antibody titers

Interferon (IFN) alfa has been used widely for the treatment of chronic hepatitis C virus (HCV) infections but only a small number of patients treated have shown a sustained biochemical and virological response. Anti-envelope E1 and E2 antibody titers were assessed retrospectively before, during, and after treatment with IFN in order to evaluate their usefulness for the prediction and monitoring of therapy outcome in 115 patients infected chronically with HCV genotype 1b. At baseline, E2 induced more frequent and stronger immunogenic responses than E1, irrespective of patient response to therapy. E1 and E2 antibodies also tended to be higher in patients with a long-term or a transient response to IFN treatment than in patients who were absolute non-responders. In most patients, E1 and E2 antibody levels tended to be lower after treatment. This reduction was most pronounced and occurred most frequently in long-term responders to therapy. In this patient group, the reduction of E1 antibodies was more pronounced than that of E2 antibodies. In contrast to E2 antibodies, the decrease of E1 antibodies could already be observed at the end of therapy (week 24) and was significantly larger (p<0.05) than that observed in relapsers and non-responders. Thus, a sustained elevation of E1 antibodies seems to be associated with ongoing infection even when HCV RNA levels were undetectable in serum. Monitoring of E1 antibody titers may represent a useful additional marker to discriminate sustained responders from those who relapse in patients receiving interferon therapy.     

Antiviral treatment for human immunodeficiency virus patients co-infected with hepatitis B virus: combined effect for both infections, an obtainable goal?

A large percentage of human immunodeficiency virus (HIV) patients have serological evidence of a past or present hepatitis B virus infection (HBV). Long-term survival is increasing for HIV patients because of highly active antiretroviral therapy. Therefore, the chronic hepatitis B infection may become an important determinant of disease outcome in these co-infected patients. We describe two HIV/HBV co-infected patients who were treated with extended antiviral therapy, initially indicated for the HIV infection. Lamivudine, a suppressor of viral replication in both infections, was one of these antiviral drugs. One patient showed a severe rebound of the HBV after withdrawal of lamivudine, the other patient developed a mutant hepatitis B virus after 18 months of treatment. This mutation was exclusively induced by lamivudine. These patients show that, with improved HIV-related survival, the HBV infection should be monitored carefully, thereby enabling the physician to interfere with therapy when necessary.     

Newly Identified Enterovirus C Genotypes,Identified in the Netherlands through Routine Sequencing of All Enteroviruses Detected in Clinical Materials from 2008 to 2015

Enteroviruses (EVs) are a group of human and animal viruses that are capable of causing a variety of clinical syndromes. Different genotypes classified into species can be distinguished on the basis of sequence divergence in the VP1 capsid-coding region. Apparently new genotypes are discovered regularly, often as incidental findings in studies investigating respiratory syndromes or as part of poliovirus surveillance. Recently, some EVs have become recognized as significant respiratory pathogens, and a number of new genotypes belonging to species C have been identified. The circulation of these newly identified species C EVs, such as EV-C104, EV-C105, EV-C109, and EV-C117, nevertheless appears to be limited. In this report, we show the results of routine genotyping of all enteroviruses detected in our tertiary care hospital between January 2008 and April 2015. We detected 365 EVs belonging to 40 genotypes. Interestingly, several newly identified species C EVs were detected during the study period. Sequencing of the 5′ untranslated region (5′ UTR) of these viruses shows divergence in this region, which is a target region in many detection assays.     

Ketamine for chronic pain: risks and benefits

The anaesthetic ketamine is used to treat various chronic pain syndromes, especially those that have a neuropathic component. Low dose ketamine produces strong analgesia in neuropathic pain states, presumably by inhibition of the N-methyl-D-aspartate receptor although other mechanisms are possibly involved, including enhancement of descending inhibition and anti-inflammatory effects at central sites. Current data on short term infusions indicate that ketamine produces potent analgesia during administration only, while three studies on the effect of prolonged infusion (4–14 days) show long-term analgesic effects up to 3 months following infusion. The side effects of ketamine noted in clinical studies include psychedelic symptoms (hallucinations, memory defects, panic attacks), nausea/vomiting, somnolence, cardiovascular stimulation and, in a minority of patients, hepatoxicity. The recreational use of ketamine is increasing and comes with a variety of additional risks ranging from bladder and renal complications to persistent psychotypical behaviour and memory defects. Blind extrapolation of these risks to clinical patients is difficult because of the variable, high and recurrent exposure to the drug in ketamine abusers and the high frequency of abuse of other illicit substances in this population. In clinical settings, ketamine is well tolerated, especially when benzodiazepines are used to tame the psychotropic side effects. Irrespective, close monitoring of patients receiving ketamine is mandatory, particularly aimed at CNS, haemodynamic, renal and hepatic symptoms as well as abuse. Further research is required to assess whether the benefits outweigh the risks and costs. Until definite proof is obtained ketamine administration should be restricted to patients with therapy-resistant severe neuropathic pain.