Potential role of the ABCG2-Q141K polymorphism in type 2 diabetes

Type 2 diabetes mellitus (T2DM) is a complex metabolic disease and variations in multispecific membrane transporter functions may affect T2DM development, complications or treatment. In this work we have analyzed the potential effects of a major polymorphism, the Q141K variant of the ABCG2 transporter in T2DM. The ABCG2 protein is a multispecific xeno- and endobiotic transporter, affecting drug metabolism and playing a key role in uric acid extrusion. The ABCG2-Q141K variant, with reduced expression level and function, is present in 15-35% of individuals, depending on the genetic background of the population, and has been shown to significantly affect gout development. Several other diseases, including hypertension, chronic renal failure, and T2DM have also been reported to be associated with high serum uric acid levels, suggesting that ABCG2 may also play a role in these conditions. In this work we have compared relatively small cohorts (n = 203) of T2DM patients (n = 99) and healthy (n = 104) individuals regarding the major laboratory indicators of T2DM and determined the presence of the SNP rs2231142 (C421A), resulting the ABCG2-Q141K protein variant. We found significantly higher blood glucose and HbA1c levels in the T2DM patients carrying the ABCG2-Q141K variant. These findings may emphasize the potential metabolic role of ABCG2 in T2DM and indicate that further research should explore how prevention and treatment of this disease may be affected by the frequent polymorphism of ABCG2.

Altered gene expressions in periferal blood cells of first-degree non-diabetic relatives of type 2 diabetic patients

Introduction and aim: We were looking for altered gene expression on peripheral blood cells significant to type 2 diabetes causing the world epidemic. Method: Muscle biopsy samples of healthy volunteers with (n = 6) or without (n = 6) first degree type 2 diabetic relatives were analyzed by mRNS microarray. After confirmation of microarrays results by quantitative real-time PCR, the expression of eight differently expressed genes were further investigated on peripheral blood cells of 58 healthy volunteers without diabetic relatives and 58 healthy ones with first-degree type 2 diabetic relatives. Results: The expressions of SERPINF1 gene were significantly lover in blood cells both from females (relative quantification: FC - female: = 0.69, p<6*10^-3) and males (FC - male: = 0.65, p<2*10^-3) with diabetic relatives. This change may not be the consequence of worsening metabolic state as it was identical in cells of type 2 diabetic patients and in healthy volunteers with diabetic relatives. We suggest that the altered SERPINF1 gene expression in peripheral mononuclear blood cells could be a genetic definiteness. Conclusion: With the help of SERPINF1 gene expression in white blood cells and lipid and biochemical blood parameters we suggest a mathematical formula for the augury of type 2 diabetes that should be checked on a larger population, but we hope it could be used as a diabetic marker. The expression of LAMP2 gene did not differ between the two healthy groups, but it showed a maternal parent of origin effect. In the case of maternal inheritance, we found higher LAMP2 expression suggesting that gene from the mother has a determining effect. Orv Hetil. 2020; 161(18): 738-746.

From "Black Box" to a Real Description of Overall Mass Transport through Membrane and Boundary Layers

The “black box” model defines the enhancement, E the polarization modulus, C∗/Co and the intrinsic enhancement, Eo without knowing the transport mechanism in the membrane. This study expresses the above-mentioned characteristic parameters, simultaneously taking into account the mass transport expressions developed for both the polarization and the membrane layers. Two membrane models are studied here, namely a solution-diffusion model characterizing solute transport through a dense membrane and a solution-diffusion plus convection model characterizing transport through a porous membrane due to transmembrane pressure difference. It is shown that the characteristic parameters of the “black box” model (E,Eo or C∗/Co) can be expressed as a function of the transport parameters and independently from each other using two-layer models. Thus, membrane performance could be predicted by means of the transport parameters. Several figures show how enhancement and the polarization modulus varied as a function of the membrane Peclet number and the solubility coefficient. Enhancement strongly increased up to its maximum value when H > 1, in the case of transport through a porous membrane, whereas its change remained before unity in the case of a dense membrane. When the value of H < 1, the value of E gradually decreased with increasing values of the membrane Peclet number.

THE PPARGC1A - GLY482SER POLYMORPHISM (RS8192678) AND THE METABOLIC SYNDROME IN A CENTRAL ROMANIAN POPULATION

Background

The peroxisome proliferator-activated receptor-γ co-activator 1-α (PPARGC1A), a key transcription factor involved in the control of metabolism and energy homeostasis, is an important biological and positional candidate of the metabolic syndrome. Association studies of its polymorphisms, however, yielded inconsistent sometimes conflicting results, pointing to important ethnic differences, which call for replication in various populations.

Objective

In order to study its most common - potentially functional - polymorphism Gly482Ser (rs8192678), we carried out a case-control study in a central Romanian population.

Material and methods

Two hundred and ninety six patients affected by the metabolic syndrome diagnosed according to the International Diabetes Federation proposed criteria and 166 middle-aged control subjects have been investigated. Genotyping was done by PCR-RFLP, using the restriction enzyme MspI.

Results

While the G(Gly)/A(Ser) allele frequencies (66.89/33.11 vs. 71.68/28.31 %) and GG/GA/AA genotype distribution (45.27-43.24-11.48 vs. 54.21-34.93-10.84 %) differed in the metabolic syndrome and control group, the risk of developing the metabolic syndrome did not reach the limit of statistical significance (OR=1.43; p=0.06, CI 95%: 0.97-2.09). Metabolic parameters in the two study groups did not show significant differences according to the genotype (p>0.05).

Conclusion

rs8192678 could be a functional polymorphism contributing to the development of the metabolic syndrome, but probably its effect is minor, and might depend on gene-gene and gene-environment interactions. Clarification of very small effects would require larger sample sizes.

A genetikai diabeteskockázat hatása a csontanyagcsere–energia-háztartás kapcsolatokra

Introduction: Type 2 diabetes is associated with increased risk of bone fractures, and the connection between bone remodeling and carbohydrate homeostasis is decoupled. It is not known whether these phenomena are the consequence of the deteriorating glucose metabolism, and the increasing insulin resistance or they belong to the genetic risk of type 2 diabetes. Aim: The aim of the authors was to clarify the impact of genetic risk on bone and carbohydrate homeostasis connections. Method: Hyperinsulinemic-normoglycemic clamps, and oral and iv. glucose loads were done to select 18 metabolically healthy females with first degree type 2 diabetic relatives -and 26 without diabetic relatives. Results: The connections between total body glucose utilization and the activity of the bone metabolic unit were missing in healthy females with the genetic risk of type 2 diabetes, like in those with manifest diabetes. In this risk group the level of low-density-large molecular sized LDL lipids were decreased, while the high-density LDL group with low molecular size was increased. The latter change was in significant connection with increased interleukin-6 levels and increased bone resorption within the bone metabolic unit. Conclusions: These data suggest that the missing connection between glucose and bone metabolism is not the consequence of the developing insulin resistance and deteriorating glucose metabolism, but rather it belongs to the inherited diabetes risk. The etiology of this early alteration, which develops prior to glucose intolerance and insulin resistance is unknown and needs further investigations. Orv. Hetil., 2015, 156(25), 1007–1013.

Metabolic differences in healthy first-degree female relatives of type 2 diabetic patients

Introduction: Today the prevalence of type 2 diabetes reached an epidemic level. It is known that type 2 diabetes could only be prevented before the manifestation, during the “prediabetic” state, urging the development of diagnostic tests to recognize the group at risk in time. Aim: The authors explored metabolic differences between healthy, normal glucose tolerant, normal insulin resistant females having first degree relatives with and without type 2 diabetes. Method: Healthy, normal insulin sensitive females without (n = 26) and with (n = 18) type 2 diabetic relatives were investigated. Results: Healthy females with first degree diabetic relatives had lower low density lipoproteins and higher high density lipoproteins as well as higher glucose and insulin levels at the 120 min of oral glucose test as compared to those without first degree diabetic relatives. Conclusions: These results suggest that the appearance of insulin resistance is preceded by hepatic insulin resistance and impaired lipid metabolism in the symptom-free prediabetic period of genetically suceptible females. Orv. Hetil., 154 (44), 1747–1753.

[Metabolic alteration in healthy men with first degree type 2 diabetic relatives]

INTRODUCTION

The recognition of prediabetic patients with the genetic risk of type 2 diabetes is very important as prediabetes is the last stage when manifestation of diabetes could be prevented by life style modification or drug intervention. This suggests the need for diagnostic processes to trace the risk of patients in time.

AIMS

The authors looked for metabolic differences between age and BMI in adjusted healthy men with or without first degree type 2 diabetic relatives.

METHODS

The study included 73 healthy men (21 with and 52 without) first-degree relatives with type 2 diabetes.

RESULTS

Total body and muscle tissue glucose utilization, glucose tolerance did not differ between the two groups, but free fatty acid levels were not suppressed by glucose load in subjects with diabetic relatives. In addition the body fat content, leptin and IL-6 levels were higher, while adiponectin and the free fatty acid/adiponectin ratio were significantly lover in healthy men with diabetic relatives. In this group HDL cholesterol, and the large buoyant LDL fraction were lower whereas the high density LDL - small molecular lipid fraction was higher than those measured in subjects without diabetic relatives.

CONCLUSIONS

These data suggest that deteriorations of insulin sensitivity and glucose tolerance is preceded by disturbances of fatty acid metabolism. The observed alteration in free fatty acid/adiponectin ratio, and/or the absence of free fatty acid suppression during glucose tolerance tests could be a screening tool for diabetes risk among men.

Effects of catalase gene (RS769217) polymorphism on energy homeostasis and bone status are gender specific

Az oxidatív stressz kóroki szerepe a csontállapot és a szénhidrát-anyagcsere romlásában ma már elfogadott. Vizsgálatunk során az egyik legismertebb antioxidáns enzim, a kataláz +22348C>T (RS769217) polimorfizmus hatását vizsgáltuk az inzulinérzékenységre, glükózfelhasználásra és a csontok denzitására. A glükózfelhasználás mérését (hyperinsulinaemiás klemp) és a genotipizálást 51 nő (24 egészséges, 27 glükózintoleráns: IFG, IGT és kezelést nem igénylő 2DM) és 90 férfi (64 egészséges és 26 glükózintoleráns) esetében végeztük el. Az allélfrekvenciákban a vizsgált dunántúli populációban, a nemek és csoportok között nem találtunk szignifikáns különbséget. A katalázgén-polimorfizmus anyagcsere- és csonthatása a nemek szerint különbözött. Nők esetében a T-allél megjelenése szignifikánsan jobb HOMA-IR indexet (CC: 2,95±1,8 vs. CT+TT: 2,06±0,9, p<0,05) és a TT-homozygoták esetében jobb teljestest-glükózfelhasználást eredményezett (M-1: CC: 9,43±4,4 vs. TT: 13,23±1,6 mg/kg/min, p<0,05), de a csontok denzitása nem különbözött. Férfiaknál a T-allél megjelenése alacsonyabb femurdenzitással (CC: 1,110±0,17 vs. CT+TT: 1,030±0,16, p<0,05 g/cm 2 ) és jobb HOMA-indexszel (CC: 2,42±2,3 vs. CT+TT: 1,50±0,2, p<0,05 ) társult, de javulást az izomszövet cukorfelhasználásában nem mértünk. A szervezet energia-háztartását és a csontanyagcserét összekapcsoló osteocalcin anyagcsere-kapcsolata nők esetében (r = +0,4424, p<0,05, n = 23) a T-allél megjelenésekor eltűnik. A többszörös korrelációs számítások szerint a leptin/adiponektin arány nők esetében a femur, férfiak esetében az L1-4 BMD-értékét befolyásolja, de ezek a kapcsolatok a T-allél megjelenésekor megszűntek. Eredményeink eltérnek a koreai nőkön mért adatoktól, és hangsúlyozzák a genetikai vizsgálatok különböző populációkon történő ismétlésének szükségét, és az anyagcsereadatok nemek szerinti értékelésének fontosságát.

[Occurrence of GRB10 (+11275G > A) polymorphism in Hungarian population and its relationship to glucose metabolism]

In our backstage experiment with differential display method among the differentially expressed genes we found the gene of GRB10 (Growth factor Receptor-Bound protein 10). The GRB10 protein binds to insulin and insulin-like growth factor receptors and acts as a negative regulatory protein. Besides, GRB10 gene polymorphisms are connected to the development of type 2 diabetes mellitus. In this experiment we investigated the allele frequency of RS 2237457, +11275G > A polymorphism in Hungarian healthy and type 2 diabetic populations (healthy: n = 77, diabetics: n = 85). We also searched for the connections between the genotype and glucose homeostasis measured by hyperinsulinemic - normoglycemic clamps in healthy volunteers (n = 88), glucose intolerant (IFG n = 15; IGT n = 29) and non-treated type 2 diabetic patients (n = 9). We did not find significant differences in allele frequencies between the Hungarian healthy and diabetic populations (healthy: g vs. a: 62% vs. 38%; 2DM g vs. a: 70% vs. 30%). In case of females, glucose utilization did not depend on GRB10 gene polymorphisms. Insulin production after oral glucose load was increased among males with gg alleles, and not after iv. glucose administration. The glucose disposal in muscle tissue was lower and the metabolic clearance rate was also lower calculated either for total body or muscle tissue in this group. In both genders gg alleles were associated with a disadvantageous lipid profile of decreased levels of large, buoyant LDL molecules and HDL levels in females. Metabolic changes related to the polymorphism of GRB10 gene support a gender specific role of this gene in insulin sensitivity and insulin signal transduction. It may be hypothesized on the basis of the differences in insulin release after oral and iv. glucose loads that GRB10 is involved in incretin signaling pathway.

The role of osteocalcin in the connection of bone and glucose metabolism in humans

Egerekben az osteocalcin hiányakor csökken a pancreas β-sejtjeinek proliferációja, és bennük az inzulin , a zsírsejtekben pedig az adiponektin génexpressziója. Módszer: Az inzulinérzékenység, a csontállapot, illetve az osteocalcin kapcsolatát 45 egészséges (nő: 20, férfi: 25) és 92 glükózintoleráns (nő: 51, férfi: 41) egyén esetében vizsgálták. Nemenként elkülönítve mérték a testösszetételt, a csontok denzitását, a csontbontás és a csontépítés markereit és hyperinsulinaemiás-normoglykaemiás teszttel az inzulinérzékenységet tükröző cukorfelhasználást. Eredmények: Az osteocalcinszintek a két nemben hasonlóak voltak, de a glükózintoleráns férfi betegek osteocalcinszintje alacsonyabb volt, mint az egészségeseké (24,5±11 vs. 18,1±9 ng/ml, p < 0,05). Az egészséges csoportban, mindkét nemben pozitív volt a korreláció az osteocalcin és az izomszövet cukorfelhasználása között (M-érték: nők: r = +0,319, p < 0,05, férfiak: r = 0,481, p < 0,01), de a glükózintoleráns csoportokban ez a kapcsolat eltűnt. Az osteocalcin egyik nemben sem mutatott korrelációt az adiponektinszinttel. Többváltozós lineáris regresszió alapján az osteocalcin szignifikáns független prediktora az összes nő esetében az éhomi vércukor, a teljes test és az izomtömeg cukorfelhasználása, a cukorfelhasználás sebessége, az ösztradiol és az LDL-koleszterin-vérszint (92%-os determináció), míg az összes férfi esetében a szérumkalcium, az OGTT során mért glükózszintek görbe alatti területe, a szabadzsírsav-szint, az inzulogenikus index, a HOMA-IR és a has/csípő körfogat (95%-os determináció) volt. A csontbontást-csontépítést jellemző BMU-index csak nők esetében korrelált szignifikánsan az M-értékekkel. Következtetés: Vizsgálatunk egészségesek esetében megerősítette az inzulinérzékenység–osteocalcin kapcsolatot emberi vonatkozásban is, de a csontanyagcsere–energia-háztartás közötti kapcsolatban jelentős nemi különbséget talált, amely nem az osteocalcin szintjén alakult ki.

Relations between bone status and glucose metabolism with progression of insulin resistance

Az elhízás, a metabolikus szindróma, a 2-es típusú cukorbetegség és a csontritkulás előfordulása világszerte növekszik, vagyis a világméretű diabéteszjárványt az az elhízás „hajtja”, amely nők esetében erősebb csontokat eredményez. Vizsgálatunk során a glükózanyagcsere-zavar korai időszakában kerestük a csontállapot és a metabolikus paraméterek közötti összefüggéseket. A vizsgálatban 20 egészséges és 51 glükózintoleráns (49 ± 9 év) nőbeteg vett részt. Mértük a szénhidrát-, lipid- és csontanyagcsere paramétereit, a csontok denzitását (lumbális 1–4 csigolyákon és a femur nyakon); cukorterheléses és hyperinsulinaemiás-normoglykaemiás klamp vizsgálatot végeztünk. A csontok denzitása a két csoport között nem különbözött. Az egészségesek denzitása szoros kapcsolatban volt az egésztest-cukorfelhasználással (inzulinérzékenység) (gerinc r = –0,4921, p < 0,05, femur: r = –0,4972, p < 0,05), de a romló glükóztoleranciával ez a kapcsolat megszűnt (gerinc: r = –0,022, ns; femur: r = –0,3136, ns). Az adipokinek közül csak az adiponectin korrelált a denzitással, amíg ez a kapcsolat a cukoranyagcsere romlásával megmaradt a gerincen ( r = –0,5081, p < 0,05; –0,2804, p < 0,05), eltűnt a femuron ( r = –0,6742, p < 0,01; –0,1723, ns). A formációs és reszorpciós markerből képzett „reszorpciós hányados” növekedése a glükózanyagcsere romlásával csökkenő csontreszorpciót jelezte. Adataink az inzulinrezisztencia „gold standard” mérőmódszerét használva szoros kapcsolatot igazoltak a glükózanyagcsere, inzulinérzékenység és a csontok állapota között az egészséges, változó korban lévő nőkben, mely a glükóztolerancia romlásával és az inzulinrezisztencia kialakulásával megbomlik. Az egészségesekben észlelhető, de az inzulinrezisztencia kialakulásával romló, negatív adiponectin-csont kapcsolat értelmezése további vizsgálatokat igényel.

Simple PCR heteroduplex, SSCP mutation screening methods for the detection of novel catalase mutations in Hungarian patients with type 2 diabetes mellitus

BACKGROUND

The enzyme catalase is the main regulator of hydrogen peroxide metabolism. Deficiency of catalase may cause high concentrations of hydrogen peroxide and increase the risk of the development of pathologies for which oxidative stress is a contributing factor, for example, type 2 diabetes mellitus. Catalase deficiency has been reported to be associated with increased frequency of diabetes mellitus in a cohort of patients in Hungary. In this cohort, the majority of mutations in the catalase gene occur in exon 2.

METHODS

Type 2 diabetic patients (n=308) were evaluated for mutations in intron 1 (81 bp), exon 2 (172 bp) and intron 2 (13 bp) of the catalase gene. Screening for mutations utilized PCR single-strand conformational polymorphism (SSCP) and PCR heteroduplex methods. Verification of detected mutations was by nucleotide sequence analysis.

RESULTS

A total of 11 catalase gene mutations were detected in the 308 subjects (3.57%, p<0.001). Five of the 11 were at two previously reported mutation sites: exon 2 (79) G insertion and (138) GA insertion. Six of the 11 were at five previously unreported catalase mutation sites: intron 1 (60) G-->T; intron 2 (7) G-->A and (5) G-->C; exon 2 (96) T-->A; and exon 2 (135) T-->A. The novel missense mutations on exon 2 (96 and 135) are associated with 59% and 48% decreased catalase activity, respectively; the novel G-->C mutation on intron 2 (5) is associated with a 62% decrease in catalase activity. Mutations detected on intron 1 (60) and intron 2 (7) showed no change in catalase activity. The G-->C mutation on intron 2 (5) might be a splicing mutation. The two missense mutations on exon 2 (96) and (135) cause substitutions of amino acids 53 (Asp-->Glu) and 66 (Glu-->Cys) of the catalase protein. These are close to amino acids that are important for the binding of heme to catalase, 44 (Val) and 72-75 (Arg, Val, Val, His). Changes in heme binding may be responsible for the activity losses.

CONCLUSION

Mutations that cause decreased catalase activity may contribute to susceptibility to inherited type 2 diabetes mellitus. Exon 2 and neighboring introns of the catalase gene may be minor hot spots for type 2 diabetes mellitus susceptibility mutations.

Detection of a novel familial catalase mutation (Hungarian type D) and the possible risk of inherited catalase deficiency for diabetes mellitus

The enzyme catalase is the main regulator of hydrogen peroxide metabolism. Recent findings suggest that a low concentration of hydrogen peroxide may act as a messenger in some signalling pathways whereas high concentrations are toxic for many cells and cell components. Acatalasemia is a genetically heterogeneous condition with a worldwide distribution. Yet only two Japanese and three Hungarian syndrome-causing mutations have been reported. A large-scale (23 130 subjects) catalase screening program in Hungary yielded 12 hypocatalasemic families. The V family with four hypocatalasemics (60.6 +/- 7.6 MU/L) and six normocatalasemic (103.6 +/- 23.5 MU/L) members was examined to define the mutation causing the syndrome. Mutation screening yielded four novel polymorphisms. Of these, three intron sequence variations, namely G-->A at the nucleotide 60 position in intron 1, T-->A at position 11 in intron 2, and G-->T at position 31 in intron 12, are unlikely to be responsible for the decreased blood catalase activity. However, the novel G-->A mutation in exon 9 changes the essential amino acid Arg 354 to Cys 354 and may indeed be responsible for the decreased catalase activity. This inherited catalase deficiency, by inducing an increased hydrogen peroxide steady-state concentration in vivo, may be involved in the early manifestation of type 2 diabetes mellitus for the 35-year old proband.

The effects of hydrogen peroxide promoted by homocysteine and inherited catalase deficiency on human hypocatalasemic patients

Elevated plasma homocysteine can generate oxygen free radicals and hydrogen peroxide. The enzyme catalase is involved in the protection against hydrogen peroxide. We examined the effect of oxidative stress promoted by homocysteine on erythrocyte metabolism (blood hemoglobin, MCV, folate, B12, serum LDH, LDH isoenzymes, haptoglobin) in the oxidative stress sensitive Hungarian patients with inherited catalase deficiency. The plasma homocysteine (HPLC method, Bio-Rad), folate, B12 (capture binding assay, Abbott), blood hemoglobin concentrations, blood catalase activity (spectrophotometric assay of hydrogen peroxide), and MCV values were determined in 7 hypocatalasemic families including hypocatalasemic (male:12, female:18) patients and their results were compared to those of the normocatalasemic (male:17 female: 12) family members. We found decreased (p <.036) folate (ng/ml) concentrations (male hypocatalasemic 5.44 +/- 2.81 vs. normocatalasemic 7.56 +/- 1.97, female 5.01 +/- 1.93 vs. 6.61 +/- 1.91), blood hemoglobin (p <.010, male:140.2 +/- 11.0 vs. 153.6 +/- 11.6 g/l, female: 128.4 +/- 10.9 vs. 139.6 +/- 9.2 g/l). Increased levels of MCV (p <.001) were detected in hypocatalasemic patients (male: 98.6 +/- 3.4 vs. 90.1 +/- 7.5 fl, female: 95.9 +/- 3.9 vs. 90.1 +/- 2.5 fl), plasma homocysteine (p <.049, male: 9.72 +/- 3.61 vs. 7.36 +/- 2.10 umol/l, female: 9.06 +/- 3.10 vs. 6.84 +/- 2.50 umol/l) and not significant (p >.401) plasma B12 (male: 336 +/- 108 vs. 307 +/- 76 pg/ml, female: 373 +/- 180 vs. 342 +/- 75 pg/ml). The serum markers of hemolysis (LDH, LDH isoenzymes, haptoglobin) did not show significant (p >.228) signs of oxidative erythrocyte damage. We report firstly on increased plasma homocysteine concentrations in inherited catalase deficiency. The increased plasma homocysteine and inherited catalase deficiency together could promote oxidative stress via hydrogen peroxide. The patients with inherited catalase deficiency are more sensitive to oxidative stress of hydrogen peroxide than the normocatalasemic family members. This oxidative stress might be responsible for the decreased concentration of the blood hemoglobin via the oxidation sensitive folate and may contribute to the early development of arteriosclerosis and diabetes in these patients.

Ultrastructural localization of Hsp-72 examined with a new polyclonal antibody raised against the truncated variable domain of the heat shock protein

In spite of the intensive search for the determination of the continuously widening physiological and pathological roles of different stress proteins, their ultrastructural localization at the electron microscopic (EM) level has hardly been examined. As it becomes increasingly evident that the function and physiological effectiveness of stress proteins are highly dependent on their spatial location and their associations with diverse regulator proteins, the demand for morphological studies which can identify their detailed distribution within the cells is evident. The reason for the practical lack of studies carried out at the EM level, lies in the shortage of reagents with suitable specificity and avidity necessary for this type of examination. To create such a reagent, a polyclonal antibody was raised using a recombinant truncated form of the inducible Hsp-72 protein. The antibody was extensively characterized, using different immunochemical methods to determine and verify its specificity, and then it was tried in ultrastructural examinations. Using the new antibody, it was possible to analyze the intracellular distribution of Hsp-72 with the immunogold technique. The localization of Hsp-72 was demonstrated directly at the ultrastructural level in the cytoplasm (especially at the cisterns of the RER), in the nucleus (mainly around the heterochromatic regions) and at both sides of the nuclear envelope close to the membrane pores. Apart from these localizations, Hsp-72 was found in several membrane bordered intracellular structures, which mainly belong to the endosomal-lysosomal system. We provide the first morphological verification of the appearance of Hsp-72 on the surface of the cells. Also novel is the indication, that the stress protein may recycle from the cell surface using a common route which includes coated pits and the endosomal system.

Polymorphism of 5' of the catalase gene in Hungarian acatalasemia and hypocatalasemia

The amplified fragment length polymorphism of Hinf1 on the promoter region of the catalase gene in Hungarian acatalasemic and hypocatalasemic patients yielded three different patterns with five bands in total. The sequence analyses revealed A-to-T, C-to-A, and C-to-T mutations at positions -21, -20, and -18 upstream of the translational initiation site. The -21 A-to-T mutations were more frequent in acatalasemic and hypocatalasemic patients (36/2) than in controls (18/14). This mutation had been detected in Japanese acatalasemic patients while the other two are novel mutations. Two extra bands in the Hinf1 pattern are due to star-like activity that cleaved a G/ATTT sequence at position -4 to 0 upstream of the initiation site.

Reference ranges of normal blood catalase activity and levels in familial hypocatalasemia in Hungary

In 1756 healthy individuals the mean and S.D. values of blood catalase activity were 111.3 +/- 16.5 MU/l with lower blood catalase for females (107.7 +/- 14.4 MU/l, n = 880) than for males (117.9 +/- 16.8 MU/l, n = 876) while the ratios of blood catalase activity to blood hemoglobin concentration were not different (0.841 +/- 0.107 MU/g versus 0.849 +/- 0.119 MU/g). The decrease of blood catalase with age was greater in males (b = -0.084 MU/l year) than in females (b = -0.016 MU/l year). The screening of 3300 healthy citizens for hypocatalasemia yielded six families (0.18%), and three families were identified out of 1630 clinic patients. These nine families revealed 37 hypocatalasemic patients with 57.5 +/- 11.7 MU/l mean and S.D. of blood catalase activity. Similarly to the Japanese and the Hungarian actalasemic patients, the electrophoretic mobilities of catalase in erythrocytes of hypocatalasemic patients were indistinguishable from that of healthy controls.

Hungarian hereditary acatalasemia and hypocatalasemia are not associated with chronic hemolysis

Two Hungarian acatalasemic and eight hypocatalasemic patients revealed normal erythropoesis. Contrary to their decreased defence system against the toxic hydrogen peroxide, the biochemical tests (serum catalase, serum hemoglobin, serum lactate dehydrogenase (LDH) ratio of LDH1 and LDH2 isoenzymes and serum haptoglobin) excluded hemolysis. The normal activity of glutathione peroxidase and the decreased catalase activity could prevent the lysis of the erythrocytes. In the presence of extremely high levels of hydrogen peroxide acute hemolysis may not be excluded; therefore, follow-up of these patients is required.