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Biomedical subjects

G Gál

Publications and source records attributed to G Gál.

At least 19 recordsLinked to original sources
PubMed2006

Soft ligands--biodegradable complexants in plant cultivation and environmental protection.

In this paper, the place and role of biodegradable complexants in light of modern plant cultivation criteria is discussed. From this point of view, micro- and macroelement (metal) chelators play a remarkable role. They are widely used in a variety of consumer products and processes, especially in agriculture. The great majority of the traditional chelators (e.g., EDTA) are, however, essentially non-biodegradable. We have systematically investigated some new biodegradable ligands with polyaminopolycarboxylic structure. We conclude that these compounds may be considered as a special group of the soft (safer) chemicals proposed first by Bodor based on retrometabolic concepts. We studied the structural conditions of biodegradability, especially regarding the new ligands, by the physicochemical characterization of their complexes formed with micro- and macroelements. The study of the complicated equilibrium conditions required the prior determination of the stability constants of the metal aqua/hydroxo complexes and the protonation constants of the ligands as well. Knowledge of the pH-dependence of the proper competitive equilibriums allowed the optimization of the investigated complexation reactions. The protonation and stability constants obtained were compared with the adequate values of the traditional, but weakly biodegradable EDTA. Excellent or very good linear correlations have been found between the logarithms of the different ligands' protonation constants, but the slopes of the straight lines were different and generally smaller than EDTA's corresponding values. Presumably, the log stability constants (logK(st)) of complexes formed by different ligands (X(m), X(n)) having analogue structures with a given metal-ion series (M(i), i = 1, 2, ...) are linearly correlated [i.e., log K(X(m)M(i)) = a log K(X(n)M(i)) + b], just as the stability constants of complexes formed by different ions (M(k), M(l)) with a given ligand series (X(j), j = 1, 2, ...). Based on the rich data basis of EDTA, these regression equations allow the calculation of some still unmeasured stability constants of the new biodegradable complexes. In the analysis of structural effects we would like to especially highlight the role of stereochemical relations in addition to the usual structural elements. From this point of view, the eventual presence of chiral nitrogen atoms is of particular importance. The stability of these compounds increases in their complexed form. As a special research field, we have examined the possibility of obtaining metal ion buffers. These systems may get an important role both from theoretical and practical points of view.

Biodegradation, Environmental↗
PubMed2005

The establishment of endovascular aneurysm coiling at a neurovascular unit: report of experience during early years.

The treatment of cerebral aneurysms is changing from surgical clipping to endovascular coiling (EVC) in many neurovascular centres. The aim of this study was to evaluate the technical results and clinical outcome at 6 months in a consecutive series of subarachnoid hemorrhage (SAH) patients treated with EVC, in a situation when the EVC had been established very rapidly as the first line of treatment at a neurovascular centre. The patient material comprised 239 SAH patients (155 women and 84 men, mean age 55 years, age range 16-81) allocated to EVC as the first line of treatment in the acute stage (within 3 weeks of rupture) between September 1996 and December 2000. Clinical grade on admission was Hunt & Hess (H&H) I and II in 42%, H&H III in 25% and H&H grade IV and V in 33% of the patients. The aneurysm was located in the anterior circulation in 82% of the cases. EVC was performed on days 0-3 in 77% of the cases. EVC of the target aneurysm was able to be completed in 222 patients (93%). Complete occlusion was achieved in 126 patients (53%). Procedural complications occurred in 39 patients (16%). Favourable clinical outcome was observed in 57%, severe disability in 28% and poor outcome in 14% of the patients. Favourable outcome was achieved in 77% of H&H I and II patients and in 43% of H&H III-V patients. The multivariate logistic regression analysis revealed that younger age, good neurological grade on admission, absence of intracerebral hematoma and intraventricular hematoma respectively, ICA-PcomA aneurysm location, later treatment and absence of complications were significant predictors of favourable outcome. After interventional training and installation of the X-ray system, the introduction and establishment of EVC at a neurovascular unit can be done in a short period of time and with favourable results. Future studies must concentrate on identifying factors of importance for the choice of interventional or surgical therapy. The results of this study indicate that endovascular therapy may be particularly beneficial in poor-grade patients and in patients with aneurysms in the ICA-PcomA territory.

Adolescent↗
PubMed2004

Clinical outcome after endovascular coil embolization in elderly patients with subarachnoid hemorrhage.

Subarachnoid hemorrhage (SAH) is not an unusual disease in an elderly population. The clinical outcome has improved over time. It has been suggested that elderly SAH patients would benefit from endovascular aneurysm treatment. The aim of this study was to evaluate technical results and clinical outcome in a series of elderly SAH-patients treated with endovascular coil embolization. Sixty-two patients (> or = 65 years) presenting with aneurysmal SAH underwent early endovascular coil embolization at Uppsala University Hospital between September 1996 and December 2000. In all 62 cases included in the study, endovascular coil embolization was considered the first line of treatment. Admission variables, specific information on technical success, degree of occlusion and procedural complications, and outcome figures were recorded. Clinical grade on admission was Hunt and Hess (H&H) I-II in 39%, H&H III in 27% and H&H IV-V in 34% of the patients. The proportion of posterior circulation aneurysms was 24%. Coil embolization was successfully completed in 94%. The degree of occlusion of the treated aneurysm was complete occlusion in 56%, neck remnant in 21%, residual filling in 11%, other remnant in 5% and not treated in 6%. The rate of procedural complications was 11%. Outcome after 6 months was favorable in 41%, severe disability in 36% and poor in 22%. Favorable outcome was achieved in 57% of the H&H I-II patients, 47% of the H&H III patients and 17% of the H&H IV-V patients. Endovascular aneurysm treatment can be performed in elderly patients with SAH with a high level of technical success, acceptable aneurysm occlusion results, an acceptable rate of procedural complications and fair outcome results.

Age Factors↗
PubMed2004

Fractionated, stereotactic proton beam treatment of cerebral arteriovenous malformations.

OBJECTIVES: To evaluate the therapeutic efficiency and adverse effects of stereotactic proton beam treatment of cerebral arteriovenous malformations (AVM). MATERIAL AND METHODS: Twenty-six patients treated in Uppsala during 1991-97 were included (men = 14, women = 12; mean age = 39, range = 23-64). The nidus volumes ranged from 0.3 to 102 ml (mean = 24, median = 13). The follow-up included clinical evaluation, magnetic resonance imaging (and/or computed tomography) every 6-12 months for 3 years and final angiography. RESULTS: The volume changes at final follow-up in AVMs >25 ml were -89, -85, -44, -29, -7, 0, 0, +5 and +18 (%); in AVMs 11-24 ml, -100, -100, -97, -92 and 0 (%); and in AVMs <10 ml, -100, -100, -100, -100, -100, -99, -98, -50, -0 and +40 (%). Two patients were lost to follow-up due to cerebral haemorrhage and myocardial infarction. Radiology displayed significant perifocal oedema in one patient and slight oedema in four patients. Of nine patients with epilepsy, seven became seizure-free after therapy while two continued to suffer from seizures. CONCLUSION: Proton beam irradiation is successful in a relatively high proportion of intermediate and large-sized cerebral AVMs. The adverse effects are acceptable. The advantage of proton treatment compared with gamma knife and LINAC stereotactic irradiation is that protons can irradiate even large volumes with a very sharp dose profile against normal surroundings. Thus, proton beam irradiation is a valuable option in the treatment of AVMs larger than 10 ml.

Adult↗
PubMed2001

The detection of hepatitis C virus in South Hungary.

BACKGROUND: More than 100 million people are infected with hepatitis C virus (HCV) worldwide. The prevalence of HCV infection varies from country to country and the natural history of hepatitis C infection is not well understood. OBJECTIVES: The prevalence of anti-HCV positive blood donors in South Hungary was determined. Potential risk factors of HCV transmission were investigated and compared to anti-HCV-negative blood donors. Furthermore, the rate of anti-HCV positivity in children who had received one or more blood transfusions prior to the implementation of anti-HCV blood donor screening was evaluated. STUDY DESIGN: A total of 45719 blood donors and 120 children were tested for the presence of anti-HCV antibodies by second- and third-generation enzyme immunoassays. Positive results were confirmed by a recombinant immunoblot assay. Data on potential sources of HCV transmission were obtained by interviews. RESULTS: Among blood donors, the rate of confirmed HCV antibody-positives was 0.4% (195 of 45719 donors). Previous surgery, transfusion, more than three pregnancies, and tattoos were significantly correlated with confirmed anti-HCV positivity. Two of 120 children (1.7%) were confirmed anti-HCV positives. In both of them, serum HCV RNA could be detected. CONCLUSIONS: The prevalence of anti-HCV positive blood donors in South Hungary is low. Nosocomial infections and tattooing were found to be the most important risk factors for transmission of HCV. Because of the low prevalence of anti-HCV positive blood donors, only a small number of children, who received blood transfusions prior to the implementation of anti-HCV blood donor screening, are infected with HCV.

Adolescent↗
PubMed2001

HLA immunization of haemodialysed patients in the transfusion and the erythropoietin eras.

The frequency of transfusions and the development of HLA alloimmunization in the years 1986 and 1995, representing the 'transfusion era' and the 'erythropoietin era', have been compared. The introduction of erythropoietin was found to reduce the need for transfusion in haemodialysed patients on the waiting list from 65.2% to 5.7%. The elimination of transfusions resulted in a decrease in HLA immunization from 56.5% to 35%. In those patients who were still immunized, antibody production was probably caused either by immunomodulation or by transfusions given to treat complications. Erythropoietin could be used instead of transfusions in almost all cases, except for complications involving severe bleeding.

Blood Transfusion↗
PubMed1996

[Hepatitis C virus antibody in the serum of blood donors].

Authors investigated the presence of antibody to hepatitis C virus (anti-HCV) at 67,534 blood donations, and alanin-amino-transferase (ALT) levels were analysed at the same time. The prevalence of anti-HCV antibody was 0.73% at 15,864 blood donors. Frequency of positive reactions of anti-HCV antibody increased paralelly with advance of age. Increased or high serum ALT level was found at more than 50% of samples with positive HCV reactivity. At the base of follow-up the blood donors were screened out from blood donation temporarily or definitively. Anti-HCV donors were taken to hepatic care. The treatment with interferon of HCV seropositive donors proved by PCR (polimerase chain reaction) was started. Transfusion and tattou are underlined as risk factors of HCV infection. The data were analysed according to sex and ages.

Adolescent↗
PubMed1995

[Effect of recombinant human erythropoietin on autologous blood donation for heart surgery].

Pharmacological stimulation of erythropoiesis was studied in patients selected for open heart surgery, and undergoing a programme of autologous blood predonation prior to surgery. Sixteen patients (group I: ery) received 4000 I. U. of recombinant human erythropoietin (r-huepo) subcutaneously weekly three times during a 3-week period preoperatively, another group of 21 patients (group II: control) were not given r-huepo. Patients in both groups received orally 2 x 80 mg iron daily. Predonation of five units of blood was planned in each patients, beginning on the 21. preoperative day; no blood was taken from patients if the hematocrit dropped below 0.34, or if any other complications occurred. The average amount of blood taken from patients in the ery group was 4.8 +/- 0.4 Units, and in the control group: 3.7 +/- 1.1 Units. In the ery group the planned 5 Units of blood could be taken from 13/16 patients, while in the controls only from 7/21. The differences are statistically significant. Reticulocyte counts were significantly higher consecutively during the preoperative period in the ery group than in the controls. In the postoperative period erythropoiesis was less pronounced in the ery group than in the controls. It is concluded that 1. r-huepo is an effective drug in preventing (or reducing) the anaemia due to repeated preoperative blood withdrawals, and thus larger amounts of autologous blood will be available for predonation. 2. More pronounced decrease of circulating reticulocytes observed in the postoperative period points to a possible suppression of endogenous erythropoietin production in the ery group.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Loss, Surgical↗
PubMed1992

[Hepatitis B virus markers and anti-HCV antibodies in hemodialyzed patients].

Serum samples from 155 patients on haemodialysis were examined for markers of hepatitis B and C. Abbott and Ortho Elisa tests were used for the determinations. ALT levels were analysed at the same time. Of the 345 random blood donors and 366 prisoners examined, 1.44% proved to be anti-HCV antibody positive. 13 medical staff workers of 147 were found to be positive for anti-HCV antibody (19.1%). In patients on chronic haemodialysis 41.29% anti-HCV antibody prevalence was found. The prevalence of anti-HBc and anti-HCV antibodies in correlation with the number of transfusions was examined as well, in serums of chronic uraemic patients. Anti-HBc antibody prevalence was significantly higher in the polytransfused group (p less than 0.01), compared to the group without transfusion. There were no correlation between the number of transfusions and anti-HCV antibody occurrence. ALT values were in correlation with HBV and HCV seropositives. Elevated ALT levels were found in patients with HBV and/or HCV infection. In conclusion, screening for HBV and HCV markers among patients receiving blood, blood donors and medical staff workers seems to be necessary in the future. The results suggest the determination of anti-HBc to be an early and common marker of hepatitis B and C and the frequent occurrence of nosocomial transmission and the importance of prevention at high risk patients.

Biomarkers↗
PubMed1992

Disinfection of regenerated dialyzers with ozone.

Regenerated, ozone-disinfected dialyzers were use for a total of 190 hemodialyses in 35 patients without the occurrence of any complication or pyrogen reactions; the efficiency of hemodialysis was identical with that of new or formalin-disinfected dialyzers. The priming fluid contained in both compartments of ozone-disinfected dialyzers proved to be sterile. The ozone did not damage the dialyzer membrane or the supporting structure of dialyzer. Ozone can effectively substitute formalin and other chemical sterilants as a disinfectant of regenerated capillary dialyzers. The process can also be automated.

Blood Cell Count↗
PubMed1991

[Incidence of the anti-N-like antibodies in the serum of patients dialyzed for chronic uremia].

The authors examined the serum of 164 hemodialysed chronic uremic patients for the detection of anti-N-like antibodies in two time intervals (in 1982 and 1988). The hemodialysis treatment was done in both intervals with regenerated, formaline-sterilized capillary dialysers. In 1982 antibodies could be detected in 5 out of 44 patients (11.3%) while in 1988 the ratio was 3 out of 120 (2.5%). The control group consisted of 40 healthy blood donors and 27 such dialysed patients who were treated only with new, ethylene oxide-sterilized single use capillary dialysers. The special cold agglutinine was not detectable in the serum of the subjects of the control group.

Formaldehyde↗
PubMed1991

[The effect of hemodialysis, using acetate and bicarbonate, on erythrocyte deformability].

The red blood cell filtration parameters were examined in 82 patients with chronic renal failure and 50 healthy controls. The most expressed decrease in deformability was observed in uremic patients who had not been haemodialysed; the values nearest to the healthy ones were observed in transplanted patients. The deformability was considerably improved after haemodialysis, especially when acetate-containing dialyzing solution was applied.

Acetates↗
PubMed1989

[Experience with the regeneration and repeated use of dialyzers (1977-1987)].

During ten years 59616 haemodialyses were performed with 18139 capillary dialysers on 226 patients being in the final stage of chronic renal insufficiency. With the semi-automatic technique applied blood can be eliminated from the dialyser in 15-20 minutes. Formalin used for desinfection is washed out of the apparatus such a way, that formalin content of the last washing solution ranges between 0-0.1 microgram/ml. Anti-N antibody indicating the presence of formalin could be detected in the serum of 2 patients out of the 120 cases tested. The same dialyser is used repeatedly on one patient, 3.29-times on the average. The regenerated dialyser eliminates compounds of small-and middle molecular weight with the same efficiency up to the 4th repeated use. Ratio of pyrogenic reactions is low, 0.08%. Neither infection or sepsis associated with the regeneration occurred. Rehabilitation degree as well as the survival time of patient corresponded with the average European standard. Because of the "first use syndrome" (allergic symptoms, hypotension, nausea, vomiting, headache, cramps etc.) with 5 patients haemodialysis could be performed only with regenerated dialysers dialyses. From the considerable sums saved by regeneration process 7 satellite dialysing units were established and equipped.

Dialysis Solutions↗
PubMed1989

[False positive results of HIV virus tests in patients undergoing chronic hemodialysis].

The sera of 173 haemodialysis patients treated in two dialysis centers in Hungary were tested for the presence of HIV (HTLV III/LAV) antibodies. Four different commercial enzyme immunoassay (EIA) kits and two types (CEM/LAV, and H9/HTLV III) of indirect immunofluorescence assay (IFA) were used. The Western blot technique was applied as confirmatory test in the study. No confirmed positive results were found in any of the cases. However, in 15 patients (8.7%) false positive (not confirmable by the Western blot assay) results were obtained in at least one but mostly in all of the three type 1 EIA kits (ORGANON, ELECTRONUCLEONICS, SORIN) applied. In 4 patients, the IFA assay also gave false positive results which could be repeated in sequential samples taken from the same patients. Increased reactivity in the control plate (coated with a concentrate of cellular material shed by uninfected H9 cell line) of the SORIN kit was found only in a few false positive samples and no fluorescence with the uninfected H9 or CEM cells was observed in any of the sera showing a false positive IFA. These results indicate that the false positive anti-HIV results frequently observable in haemodialysis patients are not simply the consequence of the presence of antibodies reacting with the uninfected H9 and/or CEM cells but they are most probably due to antibodies against antigens expressed on these cells only after infection with the human immunodeficiency virus.

False Positive Reactions↗
PubMed1988

Changes and correlations of antioxidant enzymes, lipid peroxidation and serum neutral lipids due to haemodialysis treatment in chronic uraemic patients.

A study was made of the changes in the activities of the antioxidant enzymes superoxide dismutase and catalase in the blood of chronic uraemic patients before and after haemodialysis. Changes in serum lipids (primarily neutral lipids), lipoproteins and lipid peroxidation were also followed. Before haemodialysis, antioxidant enzyme activities decreased, while lipid peroxidation increased both in the plasma and in the RBC haemolysates. Quantitative changes in the lipids increased the risk factors. Haemodialysis moderated these risk factors and a tendency to improvement was observed.

Adult↗