Rapid genotyping of genetically modified laboratory animals from whole blood samples without DNA preparation.

A new, rapid method is described which permits the genotyping of genetically modified animals from a microlitre volume of whole blood samples via one step polymerase chain reaction amplification. The major advantage of the presented method is the exclusion of a DNA preparation step, which significantly reduces the time expenditure and work load of the genetic testing. Pilot studies indicate, that this method is efficient and applicable also on tissue biopsies and larger amount of blood providing a rapid and reliable new technique over conventional genotyping approaches.

Genetic polymorphisms of human ß-defensins in patients with ischemic stroke.

OBJECTIVES AND METHODS: Genetic predisposition of the inflammatory host response may affect the development of stroke. On the basis of the theory of infectious burden and risk of stroke, we considered it of interest to investigate the relevance of the single-nucleotide polymorphisms (SNPs) in the DEFB1 gene and the copy number variant (CNV) of the DEFB4 genes in ischemic stroke. RESULTS: There were no significant differences in the genotype frequencies of the three SNPs of the DEFB1 gene between the patients with stroke (n = 312) and the healthy blood donors (n = 221). However, a higher frequency of a lower (<4) copy number of the DEFB4 gene was observed in the patients with ischemic stroke as compared with the healthy controls (40% vs 24%, respectively). Additionally, low plasma concentrations of hBD-2 (187 ± 20 pg/ml) were characteristic of the patients with fewer than four copy numbers relative to those with more than four copy numbers (385 ± 35 pg/ml). CONCLUSIONS: The low copy number of the DEFB4 gene, involving a weakened antimicrobial defense of the host, might be important in the pathogenesis of stroke.

A homozygous genetic variant of mitochondrial uncoupling protein 4 affects the occurrence of leukoaraiosis.

OBJECTIVES: We hypothesized that an appropriate balance of the mitochondrial energy production is essential in the maintenance of the glia cells in the brain. The aim of this study was to examine the roles of the rs10807344 and rs2270450 genetic variants of mitochondrial uncoupling protein 4 in the development of vascular demyelinization of the white matter of the brain, referred to as leukoaraiosis (LA). The mUCPs are presumed to be of great importance in the regulation of the mitochondrial membrane potential (MMP) and the cellular energy metabolism. MATERIALS AND METHODS: An analysis was performed on the clinical and genetic data on 401 LA patients without infarction and on 451 neuroimaging alteration-free subjects. After univariate statistical approaches, logistic regression models were also used to adjust differences in significant clinical factors between the patients and controls. RESULTS: The rs10807344 CC genotype proved to exert a protective effect on the occurrence of LA (neuroimaging alteration-free controls: 57.7%, LA group: 44.9%, P < 0.0002; adjusted OR: 0.41, 95% CI: 0.2-0.68, P < 0.005). CONCLUSION: The present findings indirectly raise the possibility that a shift or imbalance in the finely regulated MMP may play a role in the development of LA.

In vitro efficacy of amphotericin B, 5-fluorocytosine, fluconazole, voriconazole and posaconazole against Candida dubliniensis isolates using time-kill methodology.

Candida dubliniensis is a recently described yeast that causes infections in mucosal surfaces as well as sterile body sites. Candida dubliniensis develops resistance to fluconazole (FLC) more rapidly than the closely related species C. albicans. The killing activity of amphotericin B (AMB), 5-fluorocytosine (5FC), FLC, voriconazole (VRC) and posaconazole (POS) was determined against six C. dubliniensis clinical isolates, identified using molecular biological methods and C. dubliniensis CD36 reference strain. Minimum inhibitory concentrations (MICs) were determined using the Clinical and Laboratory Standards Institute standard procedure. Time-kill assays were performed using RPMI-1640 as test media over a 48-h period. AMB proved to be fungicidal at >or=0.5 microg ml(-1) against all clinical isolates after 48 h. 5FC was only fungicidal at 32-64x MIC (4-8 microg ml(-1)) against all C. dubliniensis isolates. FLC, VRC and POS were fungistatic; decrease in colony number was observed only at the highest concentrations tested (8, 4 and 4 microg ml(-1), respectively). Triazoles invariably showed fungistatic effect at concentrations attainable in the serum. In clinical situations when a fungicidal antifungal is desirable, AMB may be used.

Relevance of the genetic polymorphism of NOD1 in Chlamydia pneumoniae seropositive stroke patients.

BACKGROUND AND PURPOSE: Chronic infections with certain pathogens, such as Chlamydia pneumoniae, and genetic parameters that influence inflammatory reactions have been suggested to contribute to ischaemic stroke. NOD1 is a potent cytosolic receptor for C. pneumoniae. The aim of this study was to investigate the genetic polymorphism of NOD1 from the aspect of the development of stroke. MATERIALS AND METHODS: A total of 280 patients with ischaemic stroke were enrolled in the study; 150 healthy blood donors served as controls. The G796A (E266K) NOD1 polymorphism was determined by restriction fragment length polymorphism. Chlamydia pneumoniae seropositivity was tested by ELISA. RESULTS: There was a significant difference in NOD1 G796A genotype distribution between the controls and the stroke patients with C. pneumoniae seropositivity. The AA homozygote and GA heterozygote mutant variants were detected in 16% (25 of 152) and in 50% (77 of 152) of the C. pneumoniae-positive stroke patients, as compared with 8% (6 of 84), and 28% (24 of 84), respectively, in the C. pneumoniae-positive healthy controls. (OR = 2.559; 95% CI = 1.105-6.517, P = 0.04 and OR = 2.567; 95% CI = 1.451-4.540 P < 0.001, respectively). The stroke patients with the large vessel pathology exhibited the highest frequency of the mutant allele A (51%). In contrast, amongst the C. pneumoniae-negative subjects, no difference in genotype frequency was observed between the stroke patients and the controls. CONCLUSION: Polymorphism in NOD1 G796A alone did not prove to be a risk factor for stroke in general, but in association with C. pneumoniae infection it appeared to be accompanied by an increased risk of the development of stroke.

Endothelial nitric oxide synthase gene interactions and the risk of ischaemic stroke.

OBJECTIVE: Endothelial nitric oxide synthase (eNOS), which produces NO, plays an important role in the endothelial function under a wide range of physiological conditions. eNOS exon 7 polymorphism (Glu298Asp, G894T) has been considered to influence the risk of coronary artery disease. Alone, however, it has not been shown to be a genetic risk factor for ischaemic stroke. With the assumption of additive interactions, we examined whether the eNOS G894T or eNOS 894TT genotypes in combination with the methylenetetrahydrofolate reductase 677TT (MTHFR 677TT) or angiotensin-converting enzyme (ACE) D/D genotype could contribute to acute ischaemic stroke. MATERIAL AND METHODS: The data on 407 consecutive patients with acute ischaemic stroke who had never suffered a previous stroke event were analysed. As a control group, 295 stroke and neuroimaging alteration-free Caucasian subjects were examined. With the use of the PCR technique, the eNOS G894T, eNOS 894TT, MTHFR 677TT and ACE D/D mutations, as unfavourable common genotypes were determined in the participants. Logistic regression models were used to evaluate the roles of the genotypes and their combinations in the development of ischaemic stroke. RESULTS: The MTHFR C677TT genotype combined with the eNOS G894T or eNOS 894TT genotypes occurred significantly more frequently in the subjects with ischaemic stroke (7.1%; P < 0.025) than in the control group (3.1%). The co-occurrence of the ACE D/D genotype and eNOS G894T or eNOS 894TT was calculated to be more frequent in the ischaemic stroke group (20.9%, P < 0.0001) than in the control group (5.4%). CONCLUSION: The eNOS G894T or eNOS 894TT genotypes in combination with the MTHFR 677TT or ACE D/D genotype increases the risk of ischaemic stroke.

Specific APO E genotypes in combination with the ACE D/D or MTHFR 677TT mutation yield an independent genetic risk of leukoaraiosis.

OBJECTIVE: Ischaemic demyelination of the white matter of the brain is a frequent clinical entity. In the neuroimaging terms, it is referred to as leukoaraiosis. We earlier found that the co-occurrence of the homozygous methylenetetrahydrofolate reductase (MTHFR) 677TT and angiotensin-converting enzyme D/D (ACE D/D) genotypes yielded a highly significant moderate risk of leukoaraiosis. On the assumption of further genetic interactions, we have now investigated whether the different apolipoprotein E (APO E) genotypes, in pairwise combinations with the MTHFR 677TT or ACE D/D mutation, could lead to an increased risk of leukoaraiosis. MATERIAL AND METHODS: We analysed the occurrence of the APO E genotypes in pairwise combinations with the MTHFR 677TT or ACE D/D mutation in 315 consecutive Caucasian patients with leukoaraiosis. A total of 646 neuroimaging-free subjects acted as a control group. RESULTS: The APO E 2/2 and 2/3 or APO E 4/4 and 4/3 genotypes in combination with the MTHFR 677TT or ACE D/D mutation exhibited independent genetic risks of leukoaraiosis. CONCLUSION: The interactions of certain unfavourable genetic mutations can contribute to the evolution of leukoaraiosis.

Evaluation of the modifying effects of unfavourable genotypes on classical clinical risk factors for ischaemic stroke.

OBJECTIVES: Ischaemic stroke is a frequent heterogeneous multifactorial disease that is affected by a number of genetic mutations and environmental factors. We hypothesised the clinical importance of the interactions between common, unfavourable genetic mutations and clinical risk factors in the development of ischaemic stroke. METHODS: The Factor V Leiden G1691A (Leiden V), the prothrombin G20210A, the methylenetetrahydrofolate reductase C677T (MTHFR C677T) mutations, the angiotensin converting enzyme I/D (ACE I/D), and apolipoprotein allele e4 (APO e4) genotypes were examined by the polymerase chain reaction (PCR) technique in 867 ischaemic stroke patients and 743 healthy controls. Logistic regression models were used to estimate the roles of the co-occurrences of the clinical risk factors and common genetic mutations in ischaemic stroke. RESULTS: The Leiden V mutation in combination with hypertension or diabetes mellitus increased the risk of ischaemic stroke. We found synergistic effects between the ACE D/D and MTHFR 677TT genotypes and drinking or smoking. The presence of the APO e4 greatly facilitated the unfavourable effects of hypertension, diabetes mellitus, smoking, or drinking on the incidence of ischaemic stroke. CONCLUSION: In certain combinations, pairing of common unfavourable genetic factors, which alone confer only minor or non-significant risk, with clinical risk factors can greatly increase the susceptibility to ischaemic stroke.

Evaluation of the roles of common genetic mutations in leukoaraiosis.

OBJECTIVES: Leukoaraiosis, a relatively frequent neuroimaging entity, is presumed to be primarily a vascular problem. However, it can be explained only in part by vascular risk factors. With the assumption of genetic susceptibility, the roles of common genetic polymorphisms and mutations in leukoaraiosis were examined in this study. MATERIAL AND METHODS: A detailed clinical scrutiny of 843 Hungarian neurological patients with mild cognitive-like complaints revealed 229 subjects with leukoaraiosis that was probably vascular in origin: 143 with leukoaraiosis alone (group 1), and 86 with leukoaraiosis plus cerebral infarction (group 2). In all 229 patients, the methylenetetrahydrofolate reductase C677T (MTHFR C677T) mutation and angiotensin-converting enzyme (ACE I/D) polymorphism were examined by means of the PCR technique. The prevalences of the different genotypes for the examined mutations in the 2 groups were analysed in comparison with the data on 362 neuroimaging alteration-free subjects as controls. RESULTS: The ACE D/D genotype (38.37%, P<0.0005; OR 2.46, 95% CI, 1.49-4.08) and ACE D allele (61%; P<0.001) were more frequent in group 2 than in the control group (20.17%; 47%). Neither the homozygous nor the heterozygous MTHFR C677T mutation alone was found to be a risk factor for leukoaraiosis. The homozygous MTHFR C677T mutation combined with the ACE D/D genotype was significantly more frequent in group 1 (11.89%, P<0.0005; OR 4.75, 95% CI, 2.12-10.65), in group 2 (12.79%, P<0.0005; OR 5.16, 95% CI, 2.12-12.6) and in combined group 1+2 (12.23%, P<0.0005; OR 4.9, 95% CI, 2.33-10.3) than in the control group (2.76%). CONCLUSION: These data indicate that the contributions of the ACE D/D genotype and the homozygous MTHFR C677T mutation to leukoaraiosis should be taken into consideration not as major, but as additive factors. These findings draw attention to the fact that genetic polymorphisms that alone are insignificant can be risk factors for leukoaraiosis if they cluster in the same subjects.

Evaluation of the roles of the Leiden V mutation and ACE I/D polymorphism in subtypes of ischaemic stroke.

OBJECTIVE: The Leiden V mutation, which causes activated protein C resistance and thrombophilia, has been found to be a risk factor for venous thrombosis. The angiotensin converting enzyme (ACE) D allele indirectly exerts an unfavourable effect on the vasoregulatory system. In this study, the frequency of these mutations was analysed in different subtypes of ischaemic stroke. METHOD AND MATERIAL: According to the clinical and radiological features 664 Hungarian patients who had suffered acute ischaemic stroke were divided into 3 subtypes: small and large vessel infarcts and a mixed type. In all 664 patients, the Leiden V mutation and ACE I/D polymorphism were examined by means of the PCR technique. The frequencies of the different genotypes for the Leiden V mutation and ACE I/D polymorphism in the 3 subgroups of stroke were compared with 199 stroke-free control subjects whose MRI findings were normal. RESULTS: No significant associations were found between the overall group of cerebral infarctions and the Leiden V, ACE I/D and ACE D/D genotypes. The ACE D/D genotype was significantly more common in the patients with small deep infarcts (40.3%; p < 0.0005; OR 2.31, 95% CI 1.49-3.57) than in the control group (22.6%). The Leiden V mutation was significantly more common in patients with large infarcts (13.6%; p < 0.025; OR 2.25, CI 1.16-4.34) than in the stroke-free control subjects (6.5%). CONCLUSIONS: The ACE D/D genotype possibly contributes to the occurrence of small-vessel infarcts rather than large vessel infarcts. The Leiden V mutation might predispose to large brain infarcts. Neither the Leiden V factor nor the ACE D/D genotype has been proved to be a risk factor for ischaemic stroke as a whole.

The effects of medium-strength electric impulses on human blood.

Leukocyte subsets, total leukocyte isolates or full blood samples were subjected to medium-strength square-wave electric impulses (100 V/cm field force, 5 ms duration). On the surface of the leukocytes, the expressions of several markers (CD3, CD4, CD8, CD11a, CD11b and ICAM-1) were determined in order to study the influence of pulsed ionic currents on different aspects of the cellular immune response. Large individual differences were observed among randomly chosen healthy donors, both in the initial expression rate and in the response patterns of different antigens. As a general conclusion, it can be stated that electric impulses with the above parameters activate the state of immune response alertness of human leukocytes. Changes in the activities of several enzymes in the serum in response to electric impulses were also tested in order to examine the feasibility of ex vivo electric treatment of human blood for the establishment of an antiviral and immune activated condition. Slightly elevated lactate dehydrogenase (LDH) levels point to a possibility of enhanced haemolysis, while the lack of an elevation in the membrane-bound peroxidase activity indicates the absence of haemolysis. Significant rises were detected in the serum superoxide dismutase (SOD) activities. Since most ex vivo blood manipulations are characterised by the appearance of superoxide radicals in the serum, a SOD activity enhancement is considered beneficial in these cases. A mild, but significant reduction in the blood clotting time indicates that electric treatment of human blood should be performed with special attention to thrombosis-prone conditions, and adequate precautions and countermeasures should be introduced. Although wider examinations are required before this method can be fully recommended, ex vivo blood treatment with medium-strength electric impulses seems to be a promising adjuvant course for the establishment of acute immune potentiation and an antiviral state in patients undergoing dialysis treatment.

A clustering of unfavourable common genetic mutations in stroke cases.

OBJECTIVES: The aetiological role of common genetic mutations was analysed in a subgroup of stroke patients. MATERIAL AND METHODS: A total of 406 patients were examined because of ischaemic stroke. After a detailed clinical scrutiny, 5 were found who did not exhibit any of the classical clinical risk factors. In this clinically homogeneous subgroup of stroke patients, the prothrombin A20210G, Hong Kong, Cambridge and methylenetetrahydrofolate reductase C677T (MTHFR C677T) mutations, angiotensin-converting enzyme polymorphism (ACE polymorphism) and apolipoprotein E (APO E) genotype were examined. RESULTS: In all 5 patients, the same type of clustering of three mutations was manifested. A heterozygous Leiden V mutation was observed in all 5 subjects, while a heterozygous MTHFR C677T mutation and an I/D genotype for ACE polymorphism were detected in 4 of them, and a homozygous D/D genotype and a homozygous MTHFR C677T mutation in 1. This type of clustering of the mutations was not observed in the remaining 401 stroke patients. CONCLUSION: These results suggest that the Leiden mutation might possibly be an aetiological factor for stroke in a rare subgroup of patients who do not display any of the classical risk factors. The roles of ACE D polymorphism and the MTHFR C677T mutation in stroke, should also be taken into consideration in this subgroup of stroke patients. These unfavourable genetic factors might be aetiological factors if they are clustered together in a stroke patient not presenting any of the standard clinical risk factors.