Longitudinal Study of a Human Drug-Induced Model of Autoantibody to Cytoplasmic Rods/Rings following HCV Therapy with Ribavirin and Interferon-α

Background

A novel pattern in the indirect immunofluorescence antinuclear antibody assay on HEp-2 cells (IIF-HEp-2) characterized by cytoplasmic rods and rings (RR) was reported in HCV patients, but stringent disease specificity studies and longitudinal analysis are lacking. We investigated the clinical significance of anti-RR in an HCV cohort with up to a 12-month treatment follow up.

Methodology/Results

597 patients (342 HCV, 55 HCV/HIV, 200 non-HCV) were screened and titered for anti-RR. Serial samples were available from 78 of 176 treated and 27 of 166 untreated patients. Anti-RR was detected in 14.1% of 342 HCV patients, 9.1% of 55 HCV/HIV, 3.4% of 29 Hepatitis B, and none of 171 non-HCV (p<0.0001; HCV versus non-HCV). Anti-RR was present in 38% of 108 patients receiving interferon-α/ribavirin, but none in 26 receiving either interferon-α or ribavirin, or 166 untreated patients (p<0.0001). Other IIF-HEp-2 patterns were more frequently associated with interferon-α treatment alone (52.2%) as compared to interferon-α/ribavirin (25%), ribavirin alone (33.3%), and no therapy (26.5%). Anti-RR frequency was not associated with sex, age, ethnicity, HCV genotype or viral load. Anti-RR occurred only after initiation of treatment, beginning as early as 1 month (6%), but by the sixth month >47% tested positive for anti-RR. The anti-RR titer generally increased with sustained treatment and remained high in 53% of patients. After treatment, anti-RR titer was negative in 41%. Non-responders to HCV therapy were 77% in anti-RR-positive versus 64% in anti-RR-negative patients. Response to treatment was not associated with anti-RR titer or the dynamics of anti-RR reactivity during and after treatment.

Conclusions

The exquisite association of anti-RR reactivity with combined interferon-α/ribavirin therapy in HCV patients represents a unique model for drug-induced autoantibody generation in humans as demonstrated by the fact that a significant fraction of patients who have anti-RR during therapy becomes anti-RR-negative after completion of therapy.     

Cell surface energy,contact angles and phase partition III. Adhesion of bacterial cells to hydrophobic surfaces

The densities of adhesion of Staphylococcus epidermis, Staphylococcus aureus and Serratia marcescens to five types of plastics were studied in relation to interfacial free energies at the aqueous interfaces of both the bacteria and the plastics. The free energy of adhesion of bacteria to plastic in an aqueous medium is a linear function of partition of the bacteria between the solid surface and the liquid phase. These results show that the thermodynamics of the partitioning of a suspended particle between two immiscible liquid phases also apply to partitioning between a liquid and a solid phase.     

Frequency-dependent host selection by parasitic mites: a model and a case study

Previous studies on frequency-dependent food selection (changing food preferences in response to changes in relative food abundance) have focused on predators and parasitoids. These organisms utilize several victims during their lifetime. We introduce the case of parasites which, having accepted a host, do not change it. We propose two alternative models to explain the biased occurrence of parasites on different host types: (1) through the option of rejecting less-preferred hosts prior to accepting one of them; (2) by differential parasite survival on different host types. These models predict that host rejection, but not differential survival, can create frequency-dependent parasitism (FDP). Unlike previously described factors responsible for frequency dependence of food selection, which act through changing the foraging behaviour of individual predators or parasitoids, FDP involves no adjustment of parasite foraging strategy according to previous feeding experience. The mite Hemisarcoptes coccophagus is an obligate parasite of armoured scale insects (Homptera: Diaspididae). Our field data show that H. coccophagus is found more frequently on ovipositing than on young host females. Our model, combining the effects of host rejection and differential survival, is used to estimate the relative contribution of these factors to parasite biased occurrence on different hosts. The contribution of differential survival was dominant in H. coccophagus, and overode any effect of host rejection. Nevertheless, our prediction that FDP may be found in parasites is supported by literature data about a parasitic water mite.     

Formation and utilisation of carbon reserves by Rhizobium

The accumulation and utilisation of poly-β-hydroxybutyrate (PHB) and extracellular polysaccharide (ECPS) have been studied in Rhizobium NZP 2037 and it was found that PHB synthesis was slow during growth whereas ECPS formation was not affected. PHB synthesis only was dependent on the pH of the medium. PHB and ECPS were both used as carbon sources in the absence of other exogenous carbon. ECPS when given to starved cells as sole carbon source in the absence of nitrogen was used for PHB synthesis by the organism. In the presence of nitrogen ECPS was found to support growth. The extracellular breakdown of ECPS was demonstrated and was accompanied by the release of its constituent glucose. This was favoured by low pH.     

Adhesion,phagocytosis and cell surface energy. The binding of fixed human erythrocytes to rat macrophages and polymethylpentene

Fixed human erythrocytes were used as model particles for the study of adhesion and phagocytosis by rat peritoneal macrophages. Erythrocytes were fixed with various concentrations of glutaraldehyde or tannic acid, or were treated with neuraminidase. Adhesion and phagocytosis of these cells were measured. In addition, the surface energy of these erythrocytes and macrophages was estimated by the contact angle technique. Free energies of adhesion, based on the cell surface energies, were correlated with both adhesion and phagocytosis.     

Effects of Anabolic Steroids and High-Intensity Aerobic Exercise on Skeletal Muscle of Transgenic Mice

In an attempt to shorten recovery time and improve performance, strength and endurance athletes occasionally turn to the illicit use of anabolic-androgenic steroids (AAS). This study evaluated the effects of AAS treatment on the muscle mass and phenotypic characteristics of transgenic mice subjected to a high-intensity, aerobic training program (5d/wk for 6 weeks). The transgenic mice (CETP^+/-LDLr^-/+) were engineered to exhibit a lipid profile closer to humans. Animals were divided into groups of sedentary (Sed) and/or training (Ex) mice (each treated orally with AAS or gum arabic/vehicle: Sed-C, Sed-M, ex-C, ex-M). The effects of AAS (mesterolone: M) on specific phenotypic adaptations (muscle wet weight, cross-sectional area, and fiber type composition) in three hindlimb muscles (soleus:SOL, tibialis anterior:TA and gastrocnemius:GAS) were assessed. In order to detect subtle changes in fiber type profile, the entire range of fiber types (I, IC, IIAC, IIA, IIAD, IID, IIDB, IIB) was delineated using mATPase histochemistry. Body weight gain occurred throughout the study for all groups. However, the body weight gain was significantly minimized with exercise. This effect was blunted with mesterolone treatment. Both AAS treatment (Sed-M) and high-intensity, aerobic training (ex-C) increased the wet weights of all three muscles and induced differential hypertrophy of pure and hybrid fibers. Combination of AAS and training (ex-M) resulted in enhanced hypertrophy. In the SOL, mesterolone treatment (Sed-M and ex-M) caused dramatic increases in the percentages of fiber types IC, IIAC, IIAD, IID, with concomitant decrease in IIA, but had minimal impact on fiber type percentages in the predominantly fast muscles. Overall, the AAS-induced differential adaptive changes amounted to significant fiber type transformations in the fast-to-slow direction in SOL. AAS treatment had a significant effect on muscle weights and fiber type composition in SOL, TA and GAS which was even maximized in animals subjected to metabolically high-intensity aerobic exercise.     

Ticks (Acari: Ixodidae) of the state of Amazonas,Brazil

The tick fauna of Brazil is currently composed by 72 species. The state of Amazonas is the largest of Brazil, with an area of ≈ 19% of the Brazilian land. Besides its vast geographic area, only 19 tick species have been reported for Amazonas. Herein, lots containing ticks from the state of Amazonas were examined in three major tick collections from Brazil. A total of 5933 tick specimens were examined and recorded, comprising 2693 males, 1247 females, 1509 nymphs, and 484 larvae. These ticks were identified into the following 22 species: Amblyomma cajennense sensu lato, Amblyomma calcaratum, Amblyomma coelebs, Amblyomma dissimile, Amblyomma dubitatum, Amblyomma geayi, Amblyomma goeldii, Amblyomma humerale, Amblyomma latepunctatun, Amblyomma longirostre, Amblyomma naponense, Amblyomma oblongoguttatum, Amblyomma ovale, Amblyomma rotundatum, Amblyomma scalpturatum, Amblyomma varium, Dermacentor nitens, Haemaphysalis juxtakochi, Ixodes cf. Ixodes fuscipes, Ixodes luciae, Rhipicephalus microplus, Rhipicephalus sanguineus sensu lato. Ticks were collected from 17 (27.4%) out of the 62 municipalities that currently compose the state of Amazonas. The following four species are reported for the first time in the state of Amazonas: A. coelebs, A. dubitatum, H. juxtakochi, and Ixodes cf. I. fuscipes. The only tick species previously reported for Amazonas and not found in the present study is Amblyomma parvum. This study provides a great expansion of geographical and host records of ticks for the state of Amazonas, which is now considered to have a tick fauna composed by 23 species. It is noteworthy that we report 1391 Amblyomma nymphs that were identified to 13 different species.     

A sialylation-sensitive cell-based in vitro bioassay for erythropoietin; incorporation of the galactose-binding Erythrina crista-galli lectin.

The in vivo biological activity of erythropoietin (Epo) is dependent on its being adequately sialylated. Current in vitro bioassays for Epo do not correlate with the in vivo bioassays as the former do not take into account the role the liver plays in clearing desialylated glycoproteins from the circulation. Here we describe a sialylation-sensitive cell-based Epo bioassay. In the first instance, Epo activity in vitro was measured using proliferation of AS-E2 cells, and in vivo using the polycythaemic mouse bioassay. Activity in vivo was progressively abolished by controlled desialylation, whereas activity in vitro was essentially unaffected. Incorporation of an incubation step with a solid-phase galactose-binding lectin (Erythrina crista-galli), effectively mimicking passage through the liver in vivo, renders the in vitro bioassay sensitive to desialylation, such that Epo desialylated almost to completion had <10% of the activity of untreated Epo. These studies offer proof of principle, that rational manipulation of in vitro bioassays can allow prediction of activity in vivo without the use of live animals.