Disturbances of anticoagulation and fibrinolytic systems in monoclonal gammopathies-another mechanism of M-protein interference with hemostasis

Monoclonal gammopathies (MG) may be associated with unique monoclonal immunoglobulin (MIg)-induced disturbances of either primary hemostasis or plasma coagulation. We have investigated the possible interference of MIg with antithrombotic systems in 49 patients with MG. Although an increase of tissue-type plasminogen activator (t-PA) activity was the most frequent abnormality in our group, defect of anticoagulation factors was found in 26.5% of patients. The relationship between MIg type and concentration and frequency of antithrombotic factor abnormalities was not found. The risk of venous thrombosis was higher in patients with the defect in comparison with the unaffected group (46% vs. 22%), but the difference was not statistically significant. Bleeding complications were markedly less frequent in the group of patients with defect of anticoagulation mechanisms (0% vs. 17%). In conclusion, we have found abnormalities in anticoagulation and/or fibrinolytic system, analogous to well-known disturbances of hemostatic mechanisms, in more than a quarter of patients with MG. The interference of M-protein with antithrombotic pathways is supposed to be another mechanism of secondary deficiencies of antithrombin III (AT III), protein C (PC), protein S (PS), plasminogen and APC resistance. Together with other factors, it could contribute to higher risk of thromboembolism in myeloma patients.     

Microsatellite instability in hematological malignancies

The replication error (RER+) phenotype, characterized by microsatellite instability (MSI) has been recently related to mutations of genes involved in DNA mismatch repair pathway. These genetic alterations were first described in hereditary non polyposis colorectal cancer (HNPCC). We examined 44 patients with hematological malignancies (27 AML, 9 MDS, 2 CML-BP and 6 T-ALL) for evidence of MSI. Twenty seven percent of our patients showed differences for only one marker. In four cases (9.1%) MSI was observed in multiple markers and these cases were described as RER+ phenotype. Presented data suggest that this phenomenon may play a role in at least a subset of patients with hematological malignancies.     

Influence of New Fenpropimorph Fungicides on the Growth and Sterol Composition in Saccharomyces cerevisiae: Relationship Between Structure and Activity

The toxicity of fenpropimorph and seven newly synthesized analogues against Saccharomyces cerevisiae has been determined in liquid media. The inhibitory effect of the most efficient derivative is 120 times more than that of standard fenpropimorph. The non-linear relationship between hydrophobicity and toxicity indicates that the binding of the compounds to the receptors does not differ and so the differences in toxicity reflect changes in the rate of metabolism. The presence of inhibitors in the fermentation medium resulted in a reduction in harvested biomass and lipid yield, and changes in sterol composition - the amount of ergosterol decreased whereas the amounts of lanosterol, dihydroergosterol and squalene increased. The toxicity of the compounds was most influenced by their lipophilicity. Use of this information could lead to development of more potent ergosterol inhibitors.     

Commensal bacteria (normal microflora), mucosal immunity and chronic inflammatory and autoimmune diseases

Commensal microflora (normal microflora, indigenous microbiota) consists of those micro-organisms, which are present on body surfaces covered by epithelial cells and are exposed to the external environment (gastrointestinal and respiratory tract, vagina, skin, etc.). The number of bacteria colonising mucosal and skin surfaces exceeds the number of cells forming human body. Commensal bacteria co-evolved with their hosts, however, under specific conditions they are able to overcome protective host responses and exert pathologic effects. Resident bacteria form complex ecosystems, whose diversity is enormous. The most abundant microflora is present in the distal parts of the gut; the majority of the intestinal bacteria are Gram-negative anaerobes. More than 50% of intestinal bacteria cannot be cultured by conventional microbiological techniques. Molecular biological methods help in analysing the structural and functional complexity of the microflora and in identifying its components. Resident microflora contains a number of components able to activate innate and adaptive immunity. Unlimited immune activation in response to signals from commensal bacteria could pose the risk of inflammation; immune responses to mucosal microbiota therefore require a precise regulatory control. The mucosal immune system has developed specialised regulatory, anti-inflammatory mechanisms for eliminating or tolerating non-dangerous, food and airborne antigens and commensal micro-organisms (oral, mucosal tolerance). However, at the same time the mucosal immune system must provide local defense mechanisms against environmental threats (e.g. invading pathogens). This important requirement is fulfilled by several mechanisms of mucosal immunity: strongly developed innate defense mechanisms ensuring appropriate function of the mucosal barrier, existence of unique types of lymphocytes and their products, transport of polymeric immunoglobulins through epithelial cells into secretions (sIgA) and migration and homing of cells originating from the mucosal organised tissues in mucosae and exocrine glands. The important role of commensal bacteria in development of optimally functioning mucosal immune system was demonstrated in germ-free animals (using gnotobiological techniques). Involvement of commensal microflora and its components with strong immunoactivating properties (e.g. LPS, peptidoglycans, superantigens, bacterial DNA, Hsp) in etiopathogenetic mechanism of various complex, multifactorial and multigenic diseases, including inflammatory bowel diseases, periodontal disease, rheumatoid arthritis, atherosclerosis, allergy, multiorgan failure, colon cancer has been recently suggested. Animal models of human diseases reared in defined gnotobiotic conditions are helping to elucidate the aetiology of these frequent disorders. An improved understanding of commensal bacteria-host interactions employing germ-free animal models with selective colonisation strategies combined with modern molecular techniques could bring new insights into the mechanisms of mucosal immunity and also into pathogenetic mechanisms of several infectious, inflammatory, autoimmune and neoplastic diseases. Regulation of microflora composition (e.g. by probiotics and prebiotics) offers the possibility to influence the development of mucosal and systemic immunity but it can play a role also in prevention and treatment of some diseases.     

Opacification of hydrophilic MemoryLens U940A intraocular lenses: analysis of 2 explanted lenses

PURPOSE: To determine the rate of opacification of hydrophilic MemoryLens U940A intraocular lenses (IOLs) (Mentor Ophthalmics, Inc.) in the given cohort and perform a histopathological and spectrophotometer analysis of 2 explanted opacified IOLs. SETTING: Ophthalmology Department, Faculty Hospital, Nitra, Slovakia. METHOD: This retrospective study comprised 182 patients (205 eyes) who had implantation of a MemoryLens U940A IOL from June 1997 to June 2000. The patients were examined using a slitlamp to detect the presence of IOL opacification. In 4 cases, the lenses were explanted because of significant opacification and patient-reported problems; 2 lenses were provided for further analysis. One unused reference MemoryLens U940A IOL was also evaluated. All IOL were stained with von Kossa to determine the presence of calcium in the opacification. To confirm the components presence of an ultraviolet (UV) absorber, the IOLs were examined with an Avatar 330 Fourier transfer infrared (IR) spectroscope and a UV visible spectrophotometer (Philips). The IR spectrums for the IOL were identified using an IR spectrum atlas. The opacified IOLs, reference IOL, and the IOL packaging were further examined to determine the presence of silicone. RESULTS: Various amounts of opacification were found on the MemoryLens U940A IOL in 30 eyes (30 patients) (14.63%). Two explanted IOLs were positive for von Kossa staining, proving the presence of calcium deposits; the reference lens staining was negative. Spectrophotometry showed that the reference IOL and opacified IOLs were of the same polymer. The presence of the UV absorber on the benzophenone base was seen in the reference lens but not the opacified IOLs. In contrast, an increased concentration of low-molecular-weight components generated during the degradation of the polymer was present in the opacified lenses. The white cover pf the IOL is of polydimethyl siloxane, a silicone rubber. However, no silicone rubber was present in any examined lens, perhaps because the IOLs were in contact with alcohol during the histopathologic examination. CONCLUSIONS: The results indicate opacification of the hydrophilic MemoryLens U940A was caused by premature consumption of the UV absorber in the polymer component of the IOLs optic, with a subsequent degradation of the polymer. Whether silicone from the white cover led to the IOL opacification, as reported with other types of hydrophilic IOLs, could not be confirmed.     

The alteration of immune reactions in inbred BALB/c mice following low-level sarin inhalation exposure

To study the influence of low-level sarin inhalation exposure on immune functions, inbred BALB/c mice were exposed to low concentrations of sarin for 60 min in the inhalation chamber. The evaluation of immune functions was carried out using phenotyping of CD3 (T lymphocytes), CD4 (helper T lymphocytes), CD8 (cytotoxic T lymphocytes), and CD19 cells (B lymphocytes) in the lungs, blood, and spleen, lymphoproliferation of spleen cells stimulated in vitro by various mitogens (concanavalin A, lipopolysaccharides), phagocyte activity of peritoneal and alveolar macrophages, production of N-oxides by peritoneal macrophages, and the measurement of the natural killer cell activity at 1 wk following sarin exposure. The results were compared to the values obtained from control mice exposed to pure air instead of sarin. The results indicate that low doses of sarin are able to alter the reaction of immune system at one week following exposure to sarin. While the numbers of CD3 cells in the lungs, blood, and spleen were slightly decreased, an increase in CD19 cells was observed, especially in the lungs and blood. The reduced proportion of T lymphocytes is caused by decay of CD4-positive T cells. Lymphoproliferation was significantly decreased regardless of the mitogen and sarin concentration used. The production of N-oxides by peritoneal macrophages was stimulated after exposure to the highest dose of sarin, whereas their ability to phagocytize the microbes was increased after exposure to the lowest dose of sarin. The natural killer cell activity was significantly higher in the case of inhalation exposure of mice to the highest level of sarin. Thus, not only organophosphorus insecticides but also nerve agents such as sarin are able to alter immune functions even at a dose that does not cause clinically manifested disruption of cholinergic nervous system in the case of inhalation exposure. Nevertheless, the alteration of immune functions following the inhalation exposure to a symptomatic concentration of sarin seems to be more pronounced.     

Differential killing of mismatch repair-deficient and -proficient cells: towards the therapy of tumors with microsatellite instability

DNA mismatch repair (MMR) defects bring about a strong mutator phenotype and microsatellite instability (MSI). In an attempt to exploit MSI in cancer therapy, we constructed expression vectors carrying a thymidine kinase/blasticidin deaminase fusion gene downstream from a (C)(12) or an (A)(26) microsatellite and stably transfected these constructs into human cells in which the MMR status could be regulated by doxycycline. We now show that ganciclovir-resistant clones arising through frameshifts in the (C)(12) microsatellite were 20 times more frequent in cells in which MMR was inactivated. This difference may be exploited in gene therapy of tumors with MSI, which represent a substantial proportion of cancers of many different tissues.     

Oxidative stress in patients with COPD and pulmonary hypertension

OBJECTIVE: Oxidative stress plays an important role in the pathogenesis of chronic obstructive pulmonary disease (COPD). Oxidant/antioxidant imbalance has also been reported in various forms of pulmonary hypertension. The present study aimed to assess systemic oxidative stress, as reflected by serum malondialdehyde (MDA) concentrations and activities of antioxidant enzymes in erythrocytes [glutathione peroxidase (GPX), superoxide dismutase (SOD) and catalase (CAT)] in patients with and without pulmonary hypertension secondary to COPD. PATIENTS AND METHODS: Seventy-five patients (58 male) with COPD (mean age 65.1 +/- 1.2 years; mean smoking history 35.6 +/- 3.8 pack-years) were studied. Twenty-one healthy non-smokers served as a control group. Pulmonary function was evaluated with body plethysmography; mean and systolic pulmonary artery pressures (Ppa) were assessed with Doppler echocardiography. Serum concentrations of MDA and activities of GPX, SOD and CAT in washed red blood cells were measured using spectrophotometry. RESULTS: Pulmonary hypertension was present in 28 patients with COPD (systolic Ppa: 46.4 +/- 2.3 mmHg; mean Ppa: 26.0 +/- 1.9 mmHg) and absent in 47 (systolic Ppa: 22.9 +/- 0.8 mmHg; mean Ppa: 13.4 +/- 0.6 mmHg). Compared with the healthy control group, all the patients (with or without pulmonary hypertension) had higher serum MDA concentrations (1.5 +/- 0.1 versus 2.3 +/- 0.1 versus 2.3 +/- 0.1 nmol/mL, ANOVA, P < 0.001) and lower erythrocyte GPX activity (51.3 +/- 3.2 versus 42.2 +/- 2.0 versus 41.3 +/- 2.5 U/g Hb, P = 0.029), whereas SOD (1121.1 +/- 29.0 versus 1032.6 +/- 21.8 versus 1032.7 +/- 36.2 U/g Hb, P = 0.063) and CAT activities (4.9 +/- 0.2 versus 4.6 +/- 0.1 versus 4.7 +/- 0.2 U/g Hb; P= 0.454) were similar. No differences were observed in serum MDA concentrations or activities of GPX, SOD and CAT in erythrocytes between COPD patients with and without pulmonary hypertension. CONCLUSION: The study demonstrates the presence of oxidative/antioxidative imbalance in the systemic circulation in patients with COPD: compared with healthy subjects, COPD patients had higher serum MDA concentrations and lower GPX activity in erythrocytes. The magnitudes of the increase in MDA and reduction in GPX activity were similar in COPD patients with pulmonary hypertension and in those with normal pulmonary artery pressures.