Prion Protein-Specific Antibodies-Development,Modes of Action and Therapeutics Application

Prion diseases or Transmissible Spongiform Encephalopathies (TSEs) are lethal neurodegenerative disorders involving the misfolding of the host encoded cellular prion protein, PrP^C. This physiological form of the protein is expressed throughout the body, and it reaches the highest levels in the central nervous system where the pathology occurs. The conversion into the pathogenic isoform denoted as prion or PrP^Sc is the key event in prion disorders. Prominent candidates for the treatment of prion diseases are antibodies and their derivatives. Anti-PrP^C antibodies are able to clear PrP^Sc from cell culture of infected cells. Furthermore, application of anti-PrP^C antibodies suppresses prion replication in experimental animal models. Major drawbacks of immunotherapy are immune tolerance, the risks of neurotoxic side effects, limited ability of compounds to cross the blood-brain barrier and their unfavorable pharmacokinetic. The focus of this review is to recapitulate the current understanding of the molecular mechanisms for antibody mediated anti-prion activity. Although relevant for designing immunotherapeutic tools, the characterization of key antibody parameters shaping the molecular mechanism of the PrP^C to PrP^Sc conversion remains elusive. Moreover, this review illustrates the various attempts towards the development of anti-PrP antibody compounds and discusses therapeutic candidates that modulate PrP expression.     

Lumbar drainage for control of raised cerebrospinal fluid pressure in cryptococcal meningitis: case report and review

Raised intracranial pressure in the absence of ventricular dilatation is common in cryptococcal meningitis and associated with increased mortality. We report the case of a patient with HIV-associated cryptococcal meningitis, who developed increasing CSF pressure and visual impairment on therapy despite serial lumbar punctures. Insertion of a temporary lumbar drain controlled the opening pressure and resulted in full visual recovery. The advantages and necessary precautions with this approach are reviewed, and alternative protocols for the use of lumbar drains discussed.     

Toxicity of Amphotericin B Deoxycholate-Based Induction Therapy in Patients with HIV-Associated Cryptococcal Meningitis

Amphotericin B deoxycholate (AmBd) is the recommended induction treatment for HIV-associated cryptococcal meningitis (CM). Its use is hampered by toxicities that include electrolyte abnormalities, nephrotoxicity, and anemia. Protocols to minimize toxicity are applied inconsistently. In a clinical trial cohort of AmBd-based CM induction treatment, a standardized protocol of preemptive hydration and electrolyte supplementation was applied. Changes in blood counts, electrolyte levels, and creatinine levels over 14 days were analyzed in relation to the AmBd dose, treatment duration (short course of 5 to 7 days or standard course of 14 days), addition of flucytosine (5FC), and outcome. In the 368 patients studied, the hemoglobin levels dropped by a mean of 1.5 g/dl (95% confidence interval [CI], 1.0 to 1.9 g/dl) following 7 days of AmBd and by a mean of 2.3 g/dl (95% CI, 1.1 to 3.6 g/dl) after 14 days. Serum creatinine levels increased by 37 μmol/liter (95% CI, 30 to 45 μmol/liter) by day 7 and by 49 μmol/liter (95% CI, 35 to 64μmol/liter) by day 14 of AmBd treatment. Overall, 33% of patients developed grade III/IV anemia, 5.6% developed grade III hypokalemia, 9.5% had creatinine levels that exceeded 220 μmol, and 6% discontinued AmBd prematurely. The addition of 5FC was associated with a slight increase in anemia but not neutropenia. Laboratory abnormalities stabilized or reversed during the second week in patients on short-course induction. Grade III/IV anemia (adjusted odds ratio [aOR], 2.2; 95% CI, 1.1 to 4.3; P = 0.028) and nephrotoxicity (aOR, 4.5; 95% CI, 1.8 to 11; P = 0.001) were risk factors for 10-week mortality. In summary, routine intravenous saline hydration and preemptive electrolyte replacement during AmBd-based induction regimens for HIV-associated CM minimized the incidence of hypokalemia and nephrotoxicity. Anemia remained a concerning adverse effect. The addition of flucytosine was not associated with increased neutropenia. Shorter AmBd courses were less toxic, with rapid reversibility.     

Impact of Fabric Construction on Adsorption and Spreading of Liquid Contaminations

A contamination on a textile material is defined as an undesirable, local formation that deviates in appearance from the rest of the material. In this paper the relationship between the shape and surface of liquid contaminations and the firmness factor of woven fabric is investigated. The interdependence of constructional and structural parameters of raw and bleached cotton fabrics were analysed. The results show that selected contaminations are distributed differently, primarily depending on the construction characteristics of the fabric, type of contamination and hydrophilicity of cotton fabric.     

Expression of Hsp70 in kidney cells exposed to ochratoxin A

Ochratoxin A (OTA) is a possible etiological agent of endemic nephropathy, a chronic renal disease with high prevalence in limited geographic areas. Ochratoxicosis has many characteristics of different pathological states in which heat shock proteins (Hsps) are usually induced. The most inducible heat shock proteins belong to the Hsp70 family. We determined the level of expression of Hsp70 by the Western blot analysis in kidneys of rats treated with low doses of OTA and in LLC-PK1 and MDCK cells exposed to OTA. Estimation of cell viability and release of lactate dehydrogenase (LDH) confirmed the toxic effects of OTA on cultured cells. OTA affects the relative distribution of two Hsp70 isoforms (68-kDa and 74-kDa isoforms), but does not change total amount of Hsp70 in rat kidney. No changes in the Hsp70 level were detected in LLC-PK1 and MDCK cells treated with OTA, although the cells were seriously injured, as was seen from the reduced cell viability and increased release of LDH. Both cell lines were capable of having Hsp70 induced following a heat shock. However, exposure of the cells to OTA before the heat shock challenge prevented Hsp70 induction. Results of the study show that OTA does not induce Hsp70 in rat kidney or in cultured kidney cells. The absence of Hsp70 protective effects in the cells and tissues might be a possible explanation for the cumulative destructive effects of OTA and a silent onset of endemic nephropathy in humans and of OTA-induced experimental nephrotoxicity in animals.     

Extracellular matrix of Reinke's space in some pathological conditions

OBJECTIVE: Reinke's space (RS) is a highly specific structure in which the majority of vocal fold pathology occurs. The vibratory equivalents of structurally normal RS are regular vocal fold vibrations and normal glottic mucosal waves. Recently, RS has been considered to be composed not only of fibres but also of extracellular matrix (ECM), which is an extremely important component of a normal mucosal wave. As Reinke's oedema (RO) is characterized by excessive ECM in RS, we investigated the cell activity in RO tissue which is possibly responsible for excessive ECM production. MATERIAL AND METHODS: Tissue samples were obtained from 20 RO patients during microlaryngeal surgery. Tissue was analysed histochemically using the AgNOR method and the proliferation activity was assessed immunohistochemically using Ki67 monoclonal antibodies. RESULTS: AgNOR activity was detected in prominent stromal cells in 16 patients. Also, more pronounced activity, compared to the surrounding control tissue, was demonstrated in the epithelial cells of 17 patients using a Ki67 proliferation marker. Electron microscopy showed thickening and decomposition of the basement membrane in all RO tissue samples. CONCLUSIONS: Vocal fold mucosa that has been damaged by smoking and phonotrauma may react by producing excessive ECM, resulting in RO. Both epithelial and stromal cells are in a state of higher metabolic activity, indicating their role in this production.     

Body mass index in male Caucasian veterans with or without posttraumatic stress disorder

Obesity (defined as body mass index (BMI) higher than 30), is a serious and global public health problem, associated with increased morbidity and mortality and it represents a risk factor for developing various somatic and psychiatric disorders. Combat-related posttraumatic stress disorder (PTSD) is frequently associated with increased BMI which leads to overweight and obesity. We therefore evaluated BMI in the ethnically uniform Croatian male participants of the Caucasian origin, combat exposed veterans with or without PTSD, controlled for the effect of trauma, age, smoking, alcohol consumption, physical activity and comorbid psychiatric disorders, and in age matched healthy control subjects. BMI did not differ significantly between veterans with or without PTSD and healthy control subjects, or when participants were subdivided according to the age groups, BMI categories, or the presence of psychiatric disorders. Limitation of the study might be a small number of veterans with or without PTSD. Similar BMI was found in Croatian male veterans with or without PTSD, and age matched healthy control subjects. The data provided evidence of overweight and obesity in large number of veterans but also in healthy control subjects, and indicated that public health organizations should develop more effective strategies to prevent overweight and obesity.     

Vipera ammodytes bites treated with antivenom ViperaTAb: a case series with pharmacokinetic evaluation

Context: In clinical practice it is difficult to differentiate between V. berus and V. ammodytes venomous bites. In the past this was not a concern, but due to the current shortage in Viperfav? and European viper venom antiserum availability, V. a. ammodytes venomous bites have recently been treated with ViperaTAb^®, which is a pharmaceutical formulation containing a monospecific ovine Fab fragments against the venom of V. berus.

Objective: To evaluate ViperaTAb^® in V. a. ammodytes envenomations.

Materials and methods: This is a prospective case series of three consecutive patients envenomed by V. a. ammodytes snakebite treated with ViperaTAb^®. V. ammodytes venom, neurotoxic ammodytoxins, and Fab fragment levels were determined in serum samples and a pharmacokinetic analysis of the antivenom Fab fragments was carried out.

Results: Three patients bitten by V. a. ammodytes with extensive local swelling, neurological symptoms and recurrent thrombocytopenia were treated with ViperaTAb^®. V. ammodytes venom was detected in serum of all three patients. Ammodytoxins were detected in the serum of only the most severely envenomed patient who developed neurological symptoms. In the presented moderate cases, a dose of 8?mL of ViperaTAb^® reduced swelling and improved systemic effects, such as thrombocytopenia. However, this dose of ViperaTAb^® was not effective in the most severely envenomed patient with the highest serum values of V. ammodytes venom. In this case ViperaTAb^® did not stop local swelling and it had no effect on neurological signs. ViperaTAb^®’s systemic clearance, distribution and elimination half-lives were 4.3–13.4?mL/h/kg, 1.2–3.2?h and 14.1–55.4?h, respectively.

Conclusions: In patients envenomed by V. a. ammodytes venom, ViperaTAb^® reduces moderate swelling and temporarily improves systemic effects, except neurological symptoms. ViperaTAb^® application induces a decrement of V. ammodytes venom level in the blood, but did not affect serum concentration of neurotoxic ammodytoxins in the one patient with measurable concentrations.