Oxidative damage and neurodegeneration in manganese-induced neurotoxicity

Exposure to excessive manganese (Mn) levels results in neurotoxicity to the extrapyramidal system and the development of Parkinson's disease (PD)-like movement disorder, referred to as manganism. Although the mechanisms by which Mn induces neuronal damage are not well defined, its neurotoxicity appears to be regulated by a number of factors, including oxidative injury, mitochondrial dysfunction and neuroinflammation. To investigate the mechanisms underlying Mn neurotoxicity, we studied the effects of Mn on reactive oxygen species (ROS) formation, changes in high-energy phosphates (HEP), neuroinflammation mediators and associated neuronal dysfunctions both in vitro and in vivo. Primary cortical neuronal cultures showed concentration-dependent alterations in biomarkers of oxidative damage, F₂-isoprostanes (F₂-IsoPs) and mitochondrial dysfunction (ATP), as early as 2 h following Mn exposure. Treatment of neurons with 500 μM Mn also resulted in time-dependent increases in the levels of the inflammatory biomarker, prostaglandin E₂ (PGE₂). In vivo analyses corroborated these findings, establishing that either a single or three (100 mg/kg, s.c.) Mn injections (days 1, 4 and 7) induced significant increases in F₂-IsoPs and PGE₂ in adult mouse brain 24 h following the last injection. Quantitative morphometric analyses of Golgi-impregnated striatal sections from mice exposed to single or three Mn injections revealed progressive spine degeneration and dendritic damage of medium spiny neurons (MSNs). These findings suggest that oxidative stress, mitochondrial dysfunction and neuroinflammation are underlying mechanisms in Mn-induced neurodegeneration.     

Prevalence of Sexually Transmitted Infections Among Men Who Have Sex with Men in Zagreb, Croatia

We used respondent-driven sampling among men who have sex with men (MSM) in Zagreb, Croatia in 2006 to investigate the prevalence of HIV, other sexually transmitted infections and sexual behaviours. We recruited 360 MSM. HIV infection was diagnosed in 4.5%. The seroprevalence of antibodies to viral pathogens was: herpes simplex virus type-2, 9.4%; hepatitis A, 14.2%; hepatitis C, 3.0%. Eighty percent of participants were susceptible to HBV infection (HBs antigen negative, and no antibodies to HBs and HBc antigen). Syphilis seroprevalence was 10.6%. Prevalence of Chlamydia and gonorrhoea was 9.0%, and 13.2%, respectively. Results indicate the need for interventions to diagnose, treat and prevent sexually transmitted infections among this population.     

Apoptotic and anti-apoptotic factors in early human mandible development

The regulators of apoptosis Bcl-2, Bax, caspase-3, p53, and Hsp70 were analyzed immunohistochemically in the developing human mandible of eight human conceptuses from weeks 5 to 10 of gestation. During this period, all proteins displayed an increased pattern of expression in the mandible ectomesenchyme and in newly formed bone, except for caspase-3, which showed decreased expression in the ectomesenchyme, but appeared first in the ossification zone at the 7th wk of development. Simultaneously, the oral epithelium showed weak (p53) to strong (hsp70) expression of all proteins investigated, while in Meckel's cartilage cells, bcl-2 was expressed weakly and hsp70 was expressed moderately. Cells on the surface of the forming bone were predominantly bax positive, and only occasionally bcl-2 positive. Only a few cells on the surface and inside the bony spicules co-expressed bax and bcl-2. Terminal deoxynucleotidyl transferase (TdT)-mediated biotin-dUTP nick-end labelling (TUNEL)-positive cells were found to be apoptotic osteoblasts. The expression of all proteins investigated changed dynamically during early mandible development and the subsequent differentiation of Meckel's cartilage and bone. While interactions between those factors might be associated with the survival of Meckel's cartilage, in the ossification zone they might participate in the control of cell numbers, mineralization, and bone remodelling. Among many other factors, precise orchestration of pro- and anti-apoptotic factors contributes to normal mandible development.     

Low performance of the MSKCC nomogram in preoperatively ultrasonically negative axillary lymph node in breast cancer patients

BACKGROUND AND OBJECTIVES: In order to predict the nonsentinel lymph node (NSLN) metastases in sentinel lymph node (SLN) positive patients a nomogram was created at the Memorial Sloan Kettering Cancer Centre (MSKCC). The aim of our study was to validate the MSKCC nomogram in patients grouped by the preoperative ultrasound (US) examination of the axillary lymph nodes. METHODS: The MSKCC nomogram was validated separately in three groups of patients: (US-0) only clinically preoperatively negative axillary lymph nodes (126 patients), (US-1) US negative axillary lymph nodes (109 patients), and (US-2) US suspicious but fine needle aspiration biopsy (FNAB) negative axillary lymph nodes (41 patients). RESULTS: The predicted probability underestimates the actual probability with the mean absolute error equal to 0.116 in the US-0 group (P = 0.003), and overestimates the actual probability (mean absolute error equal to 0.084) in US-1 group (P = 0.033) and US-2 group (mean absolute error is 0.110) (P = 0.275). CONCLUSION: We found that the MSKCC nomogram overestimates the probability of the NSLN metastases in breast cancer patients with (i) preoperatively US negative or (ii) US suspicious, but FNAB negative axillary lymph nodes. We also found that MSKCC nomogram has only limited value in patients with only clinically negative axillary lymph nodes.     

α‐thalassaemia masked by β gene defects and a new polyadenylation site mutation on the α2‐globin gene

We report three examples of chronic anaemia involving complex combinations of α‐ and β‐globin gene defects. The first case had a potential Hb H disease caused by the classic SEA/RW deletions masked by Hb E [β26(B8)Glu→Lys] in the homozygous state. The second had an unusual Hb H disease caused by compound heterozygosity for two different α2 polyadenylation site mutations masked by a β‐thalassaemia heterozygosity. The third had an intermediate α‐thalassaemia with considerable anaemia caused by an as yet unknown polyadenylation site (AATAAA>AATAAC) mutation in combination with a common RW deletion masked by a common Hb C [β6(A3)Glu→Lys] heterozygosity. Diagnostic methods, genotype/phenotype correlations and the chance of overlooking these combinations during risk assessment in a multiethnic society are discussed.     

Hydrogen Bonding and Electrostatic Interaction Contributions to the Interaction of a Cationic Drug with Polyaspartic Acid

Purpose. To determine the mechanism and identify forces of interactionbetween polyaspartic acid and diminazene (a model drug). Such knowledgeis essential for the design of polymeric drug delivery systemsthat are based on molecular self-assembly into complexes or micellartype systems. Methods. Complex formation was studied by isothermal titrationmicrocalorimetry and the McGhee von Hippel model was applied toobtain K _obs, H _obs, and n _obs. The calorimetry data were compared withboth an optical density study and the amount of free/complexed drug. Results. The diminazene-polyaspartic acid interaction is enthalpicallydriven, whereby one diminazene molecule interacts with two monomersof polyaspartic acid. The dependence of K _obs on saltconcentrationreveals a contribution of electrostatic interactions. However, applyingManning's counter ion condensation theory shows that the major drivingforce for the complex formation is hydrogen bonding, with interfacialwater molecules remaining buried within the complex. Themodelling of the pH dependence of K _obs and H _obsdemonstrates thatthe ionization of carboxylic groups of polyaspartic acid is a prerequisitefor the interaction. Conclusions. Complex formation between diminazene and polyasparticacid is driven by both electrostatic interactions and hydrogen bonding,with the latter being the dominating force. Although electrostaticinteractions are not the major driving force, ionization of the drug andpolymer is essential for complex formation.     

Increased expression of CXCR3 and CCR5 on memory CD4+ T-cells migrating into the cerebrospinal fluid of patients with neuroborreliosis: the role of CXCL10 and CXCL11

The aim of this study was to evaluate the contribution of chemokine receptor CXCR3 and the corresponding ligands CXCL10 and CXCL11 to the recruitment of peripheral blood (PB) memory CD4+ T-cells into the cerebrospinal fluid (CSF) of patients with acute neuroborreliosis. Percentages of memory CD45RO+CD4+ T-cells expressing CXCR3 and CCR5 were significantly enriched in the CSF compared to the PB. Concentrations of CXCL10 and CXCL11 in the CSF of neuroborreliosis patients were significantly higher compared with the corresponding serum samples. Our results suggest that CXCL10 and CXCL11 create a chemokine gradient between the CSF and serum and recruite CXCR3-expressing memory CD4+ T-cells into the CSF of neuroborreliosis patients and that CCR5 also plays a role in this process.     

Ochratoxin A-induced apoptosis in rat kidney tissue

The aim of our study was to find whether ochratoxin A (OTA) induces the apoptosis and/or necrosis of kidney tissue in rats. In the first experiment, the highest number of apoptotic cells was found in rats sacrificed one day after OTA administration (1.00 mg/kg b.w., i.p.). The number of apoptotic cells reduced gradually and they were not seen nine days after OTA administration. A possible dose-dependence of histological changes was checked in kidney tissue of rats given 0.25, 0.50 or 1.00 mg of OTA/kg b.w., i.p. three times a week for four weeks. The number of apoptotic cells showed a clear dose-dependence, but necrosis was absent even at the highest doses. The time-dependent appearance of lesions related to OTA administration was checked by administering 0.50 mg OTA/kg body weight to rats, and sacrificing them one day after 1, 3, 6, and 9 doses/administrations, or 6 and 21 day after 12 doses/administrations. Long-term administration is associated with continued and increased apoptosis without necrosis, suggestive of OTA's role in the pathogenesis of progressive renal atrophy.     

Occult Micrometastases in Axillary Lymph Nodes Predict Subsequent Distant Metastases in Stage I Breast Cancer: A Case-Control Study with 15-Year Follow-Up

Background The prognostic significance of occult axillary metastases was evaluated in patients with stage I breast cancer.Methods Ninety-six patients with pT1 breast carcinoma who underwent axillary lymph node dissection had negative nodes in routine microscopic examination. Forty-eight patients developed distant metastases within 15 years after surgery (M group) and are compared to 48 age-matched patients who were disease-free for 15 years (NM group). We reexamined 1539 lymph nodes from these patients, using three levels and cytokeratin immunostain.Results Occult metastases were detected in 21 patients: 16 of 48 (34%) in the M group and 5 of 48 (11%) in the NM group (P = .007). All metastases measured 2.0 mm or less and were classified as micrometastases (>0.2 mm to 2.0 mm) in 11 cases and as individual tumor cells (individual cells or clusters measuring 0.2 mm) in 10 cases. Micrometastases were 10 times more frequent in the M group than in the NM group (10/48 vs. 1/48; P = .004). Although there was no difference in tumor size, histologic type, estrogen receptor status, or type of treatment between the two patient groups, tumors in the M group were of a higher grade, had higher mitotic index and showed lymphovascular invasion. In multiple logistic regression, only high mitotic index and presence of micrometastases showed an independent significant correlation with the subsequent occurrence of distant metastases.Conclusions The presence of micrometastases (>0.2 to 2.0 mm) in axillary nodes is significantly associated with the development of distant metastases in patients with T1 breast cancer.