Hepatitis C Screening and Treatment Program in Hungarian Prisons in the Era of Direct Acting Antiviral Agents

A hepatitis C virus (HCV) screening and treatment program was conducted in Hungarian prisons on a voluntary basis. After HCV-RNA testing and genotyping for anti-HCV positives, treatments with direct-acting antiviral agents were commenced by hepatologists who visited the institutions monthly. Patients were supervised by the prisons’ medical staff. Data were retrospectively collected from the Hungarian Hepatitis Treatment Registry, from the Health Registry of Prisons, and from participating hepatologists. Eighty-four percent of Hungarian prisons participated, meaning a total of 5779 individuals (28% of the inmate population) underwent screening. HCV-RNA positivity was confirmed in 317/5779 cases (5.49%); 261/317 (82.3%) started treatment. Ninety-nine percent of them admitted previous intravenous drug use. So far, 220 patients received full treatment and 41 patients are still on treatment. Based on the available end of treatment (EOT) + 24 weeks timepoint data, per protocol sustained virologic response rate was 96.8%. In conclusion, the Hungarian prison screening and treatment program, with the active participation of hepatologists and the prisons’ medical staff, is a well-functioning model. Through the Hungarian experience, we emphasize that the “test-and-treat” principle is feasible and effective at micro-eliminating HCV in prisons, where infection rate, as well as history of intravenous drug usage, are high.

Nem malignus, nem infectiosus lymphoproliferatio: kihívások az autoimmun lymphoproliferativ szindróma diagnosztikájában és kezelésében

Összefoglaló. Az autoimmun lymphoproliferativ szindróma egy ritka, immundeficientiával járó genetikai betegség. Hátterében az extrinszik apoptotikus útvonal génjeinek örökletes vagy szerzett mutációi és a következményesen kialakuló, aktivált lymphocyták negatív szelekciójának a defektusa áll. Az autoimmun lymphoproliferativ szindróma klinikai megjelenésére jellemző a jóindulatú lymphocytaburjánzás következtében kialakuló lymphadenopathia és lépmegnagyobbodás. Gyakran társul olyan autoimmun kórképekkel, mint az autoimmun haemolyticus anaemia vagy az autoimmun thrombocytopenia. A betegségben jellemző laboratóriumi eltérések a következők: az αβ+ CD4–/CD8– kettős negatív T-sejtek szaporulata, a szolúbilis Fas-ligand, az interleukin-10 és interleukin-18, valamint a B12-vitamin szérumszintjének emelkedése. A kórkép diagnózisához hozzátartozik az in vitro Fas-mediált apoptózis funkciójának vizsgálata, valamint a genetikai vizsgálat. Differenciáldiagnosztikai szempontból fontos elkülöníteni a lymphomáktól, valamint az autoimmun lymphoproliferativ szindrómaszerű betegségektől. A kezelés alapja a társuló autoimmun kórképek tüneteinek csökkentése immunszuppresszív terápiával. Orv Hetil. 2022; 163(4): 123–131.

Summary. The autoimmune lymphoproliferative syndrome is a rare genetic disorder causing immunodeficiency. In the background of the disease, germline or somatic mutations of genes participating in the extrinsic apoptotic pathway and the consequential defect in the negative selection of activated lymphocytes were discovered. The clinical appearance of autoimmune lymphoproliferative syndrome consists of non-malignant lymphoproliferation, lymphadenopathy and splenomegaly, it is frequently accompanied by autoimmune disorders such as autoimmune haemolytic anaemia or autoimmune thrombocytopenia. The main diagnostic laboratory findings of this disease are the following: an elevation in αβ+, CD4–/CD8– double-negative T cell count, elevated serum levels of soluble Fas-ligand, interleukin-10, interleukin-18 and vitamin B12. Other useful laboratory tests are the in vitro Fas-mediated apoptotic functional assay and the genetic screening for gene mutations. Differential diagnosis should exclude malignant lymphoproliferation in lymphomas and non-malignant autoimmune lymphoprolipherative syndrome-like diseases. The main aim of the treatment is the amelioration of the accompanying autoimmune disease with immunosuppressive therapy. Orv Hetil. 2022; 163(4): 123–131.

Joined supernumerary mandibular teeth in the premolar region: Report of a Hungarian archeological case

Supernumerary teeth are those that are additional to the normal complement. They may occur in any region of the dental arch and have been reported in both the primary and the permanent dentitions. The etiology of supernumerary teeth is still not clearly understood, but several theories have been suggested for their occurrence. The investigated material were the remains from the Bácsalmás-Óalmás burial site (from the 16th-17th centuries), where 472 skeletons were excavated from 1993 to 2003. For the purpose of this study, the dentitions of 164 adult individuals were examined. The examination was carried out using macromorphological methods, radiographic analysis and a dial caliper were applied. This paper describes a supernumerary tooth of an adult female skeleton. On the labial surface of the first mandibular premolar an extra tooth was observed.Radiographic examination of the fused teeth indicated that the crown of the premolar had fused incompletely with the crown of the extra tooth. The position of the extra tooth could have been the result of gemination of the tooth germ or the elaboration of the buccal cingulum. The cranium of the examined individual showed some mongoloid morphologic features, too. Our presumption about the formation of the supernumerary tooth may have contributed to the theories of the occurrence of supernumeraries. The sporadic occurrence of this anomaly was reported in recent and archaeological skeletal collections. This study showed that multiple permanent dental formation was present in past Hungarian populations, representing a contribution to the history of dental anomalies.

Assessment of heat provocation tests on the human gingiva: the effect of periodontal disease and smoking

Periodontal inflammation is associated with morphological changes in the blood vessels which may influence the regulation of gingival blood flow (GBF). Our aim was to adapt the heat provocation test to the human gingiva to assess vascular reactivity in periodontal inflammation.

METHOD

GBF was recorded by Laser Doppler Flowmetry before and after heat provocation in healthy volunteers (n = 50). Heat was generated either by warm saline or a halogen lamp. The latter method was also utilized for a heat test in non-smoking and smoking patients with periodontal inflammation. The circulatory parameters were correlated to the inflammatory marker, i.e. gingival crevicular fluid (GCF) production measured by Periotron.

RESULTS

Local application of heat caused a rapid, significant and transient increase in GBF regardless of the method used. The increase in the speed and not in the concentration of moving blood cells was responsible for increased GBF. Higher GCF values were correlated with increased peak flow, flux pulse amplitude and faster restoration of GBF after the test in non-smokers, but not in smokers.

CONCLUSIONS

The heat test could be a valuable tool to check the vascular reactivity of gingival vessels. Moderate periodontal inflammation may facilitate gingival vascular responsiveness which can be suppressed by smoking.

Unusual spinal tuberculosis in an Avar Age skeleton (Csongrád-Felgyő, Ürmös-tanya, Hungary): A morphological and biomolecular study

The paleopathological analysis of a well-preserved young adult female skeleton from the AD 7-8th century (Avar Age) in Hungary revealed multiple lytic lesions in all of the thoracic and lumbar vertebral bodies. The lesions were characterized by smooth marginal zones and space-occupying mass appearance. The considerable loss of spongy bone in the thoracolumbar vertebrae resulted in angular deformity and fusion, characteristic of the healing stage of TB. Osteolytic lesions were also observed on the vertebral processes, ribs and sternum. On the endocranial surface, abnormal blood vessel impressions were revealed, indicating some kind of meningitis. The X-ray and CT analysis of the affected bones detected abnormal structures and cystic zones of destruction. The lesions were however not always bordered by areas of increased density, which is typical in cystic TB. Vertebral remains were also subjected to biomolecular analysis in two different laboratories, which attested the presence of Mycobacterium tuberculosis complex (MTBC) DNA and supported the paleopathological diagnosis of TB. Spoligotyping analysis confirmed the presence of MTBC DNA and more specifically an infection caused by bacteria belonging to the M. tuberculosis lineage. This case study provides new data for the paleoepidemiology of TB in this geographical area and historical period, and draws attention to the great variability of TB lesions in the human skeleton.

Nutrient stress alters the glycosylation status of LGR5 resulting in reduced protein stability and membrane localisation in colorectal tumour cells: implications for targeting cancer stem cells

BACKGROUND

LGR5 is an important marker of intestinal stem cells and performs its vital functions at the cell membrane. Despite the importance of LGR5 to both normal and cancer stem cell biology, it is not known how microenvironmental stress affects the expression and subcellular distribution of the protein.

METHODS

Nutrient stress was induced through glucose starvation. Glycosylation status was assessed using endoglycosidase or tunicamycin treatment. Flow cytometry and confocal microscopy were used to assess subcellular distribution of LGR5.

RESULTS

Glucose deprivation altered the glycosylation status of LGR5 resulting in reduced protein stability and cell surface expression. Furthermore, inhibiting LGR5 glycosylation resulted in depleted surface expression and reduced localisation in the cis-Golgi network.

CONCLUSIONS

Nutrient stress within a tumour microenvironment has the capacity to alter LGR5 protein stability and membrane localisation through modulation of LGR5 glycosylation status. As LGR5 surface localisation is required for enhanced Wnt signalling, this is the first report to show a mechanism by which the microenvironment could affect LGR5 function.

Removal of nonspecific binding proteins from cell and tissue extracts using 2-aminobenzimidazole-tethered affinity resin

Cellular drug target identification through affinity chromatography is often hindered by the quantity of nonspecific binders, such as cytoskeletal and heat shock proteins. Thus, we prepared a 2-aminobenzimidazole-tethered depletion resin designed for removal of these proteins, and tested it on human lung carcinoma cell and rat tissue extracts. Column-bound proteins were identified by two-dimensional gel electrophoresis and MS. Among others, tubulins, actins and heat shock proteins were successfully depleted. Due to the reduction of these highly abundant proteins detection of potential drug targets is considerably facilitated in the pre-purified samples.

Influence of shear viscosity of quark-gluon plasma on elliptic flow in ultrarelativistic heavy-ion collisions

We investigate the influence of a temperature-dependent shear viscosity over entropy density ratio η/s on the transverse momentum spectra and elliptic flow of hadrons in ultrarelativistic heavy-ion collisions. We find that the elliptic flow in √S(NN)=200  GeV Au+Au collisions at RHIC is dominated by the viscosity in the hadronic phase and in the phase transition region, but largely insensitive to the viscosity of the quark-gluon plasma (QGP). At the highest LHC energy, the elliptic flow becomes sensitive to the QGP viscosity and insensitive to the hadronic viscosity.

Effects of dietary vegetable oil supplementation on fillet quality traits, chemical and fatty acid composition of African catfish (<i>Clarias gariepinus</i>)

Abstract. The effects of dietary fish oil (FO), soybean oil (SO) and linseed oil (LO) (12 % crude fat content each) in African catfish (Clarias gariepinus) diets were tested on the fillet flesh quality, chemical and fatty acid (FA) composition, after 3 and 6 weeks of feeding. The bodyweight gain of fish and the fillet dry matter, crude protein and crude fat content was not different among the divergent treatments. High (>20 %) total n3 FA supplementation significantly increased the moisture loss of fillet (FO, LO). Applying the simple FA dilution model (JOBLING 2004a, 2004b), the incorporation dynamics of the most largely dosed FAs were accurately predictable after 3 weeks (R² between observed and estimated data for total n3 FAs: FO 0.95, LO 0.73 and for α-linolenic acid, LO 0.97). In the fillet FA composition the metabolism of n3 acids was more pronounced. The large provision of α-linolenic acid (LO) had a pronounced effect on the longchain, polyunsaturated n3 FA proportions (eicosapentaenoic and docosapentaenoic acids), while no effect was experienced on docosahexaenoic acid. This study suggests that daily bodyweight gain is not, while fillet flesh quality and FA composition is slightly compromised when fish oil is substituted for vegetable oils.

Relativistic shock waves in viscous gluon matter

We solve the relativistic Riemann problem in viscous gluon matter employing a microscopic parton cascade. We demonstrate the transition from ideal to viscous shock waves by varying the shear viscosity to entropy density ratio eta/s from zero to infinity. We show that an eta/s ratio larger than 0.2 prevents the development of well-defined shock waves on time scales typical for ultrarelativistic heavy-ion collisions. Comparisons with viscous hydrodynamic calculations confirm our findings.

Modification of ionotropic glutamate receptor-mediated processes in the rat hippocampus following repeated, brief seizures

The seizure-induced molecular and functional alterations of glutamatergic transmission in the hippocampus have been investigated. Daily repeated epileptic seizures were induced for 12 days by intraperitoneal administration of 4-aminopyridine (4-AP; 4.5 mg/kg) in adult Wistar rats. The seizure symptoms were evaluated on the Racine's scale. One day after the last injection, the brains were removed for in vitro electrophysiological experiments and immunohistochemical analysis. The glutamate receptor subunits NR1, NR2A, NR2B, GluR1, GluR1(flop), GluR2, and KA-2 were studied using the histoblotting method. The semi-quantitative analysis of subunit immunoreactivities in hippocampal layers was performed with densitometry. In the hippocampus, increase of GluR1, GluR1(flop) and NR2B immunostaining was observed in most of the areas and layers. The significant decrease of GluR2 staining intensity was observed in the CA1 and dentate gyrus. Calcium permeability of hippocampal neurons was tested by a cobalt uptake assay in hippocampal slices. The uptake of cobalt increased in the CA1 area and dentate gyrus, but not in the CA3 region following 4-AP treatment. Effects of AMPA and NMDA (N-methyl-d-aspartate) glutamate receptor antagonists (1-(4-aminophenyl)-4-methyl-7,8-methylenedioxy-5H-2,3-benzodiazepine hydrochloride (GYKI 52466) and D-APV respectively) were measured in hippocampal slices using extracellular recording. Analysis of the population spikes revealed the reduced effectiveness of the AMPA receptor antagonist GYKI 52466, while the effect of the NMDA receptor antagonist d-(2R)-amino-5-phosphonovaleric acid was similar to controls. The results demonstrated that repeated convulsions induced structural and functional changes in AMPA receptor-mediated transmission, while NMDA and kainate receptor systems displayed only alterations in receptor subunit composition.

Leflunomide and its metabolite A771726 are high affinity substrates of BCRP: implications for drug resistance

BACKGROUND

Earlier publications have suggested a possible role for the efflux transporter breast cancer resistance protein (BCRP) in acquired resistance to disease-modifying antirheumatic drugs (DMARDs) such as leflunomide and its metabolite A771726 (teriflunomide). However, there is no direct evidence that BCRP interacts with these drugs.

OBJECTIVES

To characterise the interaction between BCRP transporter and leflunomide and its active metabolite A771726, with emphasis on the nature of the interaction (substrate or inhibitor) and the kinetic characterisation of the interactions.

METHODS

Different in vitro membrane-based methods (ATPase and vesicular transport assay) using BCRP-HAM-Sf9 membrane preparations and cellular assays (Hoechst assay and cytotoxicity assay) were performed on PLB985-BCRP and HEK293-BCRP cell lines overexpressing BCRP.

RESULTS

In all assays used, an interaction between the investigated drugs and BCRP was detected. In the vesicular transport assay, both leflunomide and its metabolite inhibited BCRP-mediated methotrexate transport. Both compounds are likely substrates of BCRP as shown by the vanadate-sensitive ATPase assay. In line with the membrane assays, leflunomide and A771726 inhibited BCRP-mediated Hoechst efflux from PLB985-BCRP cells. In the cytotoxicity assay, overexpression of BCRP conferred 20.6-fold and 7.5-fold resistance to HEK293 cells against leflunomide and A771726, respectively. The resistance could be reversed by Ko134, a specific inhibitor of BCRP.

CONCLUSION

Based on these results, BCRP could play an important role in the resistance to leflunomide and A771726 via interactions with these drugs. BCRP may also mediate drug-drug interactions when leflunomide is administered with other BCRP substrate drugs such as methotrexate.

Cholesterol potentiates ABCG2 activity in a heterologous expression system: improved in vitro model to study function of human ABCG2

ABCG2, a transporter of the ATP-binding cassette family, is known to play a prominent role in the absorption, distribution, metabolism, and excretion of xenobiotics. Drug-transporter interactions are commonly screened by high-throughput systems using transfected insect and/or human cell lines. The determination of ABCG2-ATPase activity is one method to identify ABCG2 substrate and inhibitors. We demonstrate that the ATPase activities of the human ABCG2 transfected Sf9 cell membranes (MXR-Sf9) and ABCG2-overexpressing human cell membranes (MXR-M) differ. Variation due to disparity in the glycosylation level of the protein had no effect on the transporter. The influence of cholesterol on ABCG2-ATPase activity was investigated because the lipid compositions of insect and human cells are largely different from each other. Differences in cholesterol content, shown by cholesterol loading and depletion experiments, conferred the difference in stimulation of basal ABCG2-ATPase of the two cell membranes. Basal ABCG2-ATPase activity could be stimulated by sulfasalazine, prazosin, and topotecan, known substrates of ABCG2 in cholesterol-loaded MXR-Sf9 and MXR-M cell membranes. In contrast, ABCG2-ATPase could not be stimulated in MXR-Sf9 or in cholesterol-depleted MXR-M membranes. Moreover, cholesterol loading significantly improved the drug transport into inside-out membrane vesicles prepared from MXR-Sf9 cells. MXR-M and cholesterol-loaded MXR-Sf9 cell membranes displayed similar ABCG2-ATPase activity and vesicular transport. Our study indicates an essential role of membrane cholesterol for the function of ABCG2.

Toxicity and degradation of benefin in chicken embryos

The herbicide formulation Flubalex (20% benefin) was applied, ROSS 308 embryonated hen eggs were treated on day 12 of incubation period. The pesticide was diluted in water to a concentration level of 3.0%, and the emulsion was injected into the air space in a volume of 0.1 ml/egg, or hen's eggs were treated by the immersion technique. Residues of benefin were measured in the samples on days 13, 15 and 19 of the incubation of chicken embryos, and morphological examinations were performed simultaneously. After the immersion treatment the mortality rate of embryos was remarkable compared to the injection treatment. Analytical chemistry data showed the concentration of the active ingredient which was 3.5 times higher on day 13 of incubation in the samples after immersion treatment than after the injection of benefin. This resulted an increased incidence rate of mortality. On day 19 of hatching period the benefin concentration was practically similar independently of treatment method. No macro- and microscopic alterations were seen.

One-generation reproduction toxicity study of mancozeb and lead acetate

The reproduction toxicity of lead acetate and 80% mancozeb containing fungicide formulation (Dithane M-45) were studied on rats. The lead acetate was applied in diet at the following dose groups: Control-1,000-5,000-10,000 mg/kg. Three treatment and a control groups were applied, 4,500 mg/kg Dithane M-45 was administered in all the dose levels simultaneously in diet. The basis of the method was the OECD Guideline for Testing of Chemicals No. 415. Clinical symptoms and mortality were not found in the parent generation. The body weight of female animals diminished significantly before the pregnancy period. This tendency was also seen on males after the combination treatment. Remarkable body weight growth of female animals was observed during lactation period at the two high dose levels. Diminished body weight data of offsprings were measured after treatment at the end of the lactation period. The histological examination showed a general tubulonephrosis in the trial. Summing up, it can be established the administration of fungicide Dithane M-45 did not increase the toxicity of lead acetate.

One-generation reproduction toxicity study of Dithane M-45 (mancozeb) and lead acetate

The reproductive toxicity of lead acetate and of a fungicide formulation (Dithane M-45) containing 80% mancozeb was studied on rats. Lead acetate was applied in the feed in the following dose groups: control, 1,000, 5,000 and 10,000 mg/kg of diet. The three treatment groups received, in addition to the above doses of lead acetate, 4,500 mg/kg Dithane M-45 in the diet. The method was based on the OECD Guideline for Testing of Chemicals No. 415 (1981). Clinical symptoms and mortality were not found in the parent generation. The body weight of female animals decreased significantly before the pregnancy period. This tendency was also seen in males after the combination treatment. At the two high dose levels a remarkable body weight increase was seen in the female animals during the lactation period. As a result of treatment, decreased body weight of offspring was measured during the lactation period. No gross pathological changes were seen. Histological examination showed general tubulonephrosis in the experimental animals. It can be established that the administration of Dithane M-45 did not enhance the reproductive toxicity of lead acetate.

Teratogenicity testing of BI 58 EC (38% dimethoate) in chicken embryos with special respect to degradation of the active ingredient

The insecticide formulation BI 58 EC was tested for teratogenicity in chicken embryos, with particular reference to degradation of the active ingredient (dimethoate) after the treatment of embryonated eggs. The pesticide was diluted in water to a concentration level of 0.8%, and the emulsion was injected into the air space in a volume of 0.1 ml/egg, or hen's eggs were treated by the immersion technique. Residues of dimethoate were measured in the samples on days, 13, 15 and 19 of the incubation of chicken embryos, and morphological examinations were performed simultaneously. Analytical chemistry data indicated a slower degradation of dimethoate in embryos after the immersion of eggs, and cyllosis was remarkable in this group among the sporadic developmental anomalies. The liver tissues of both treated groups exhibited severe fatty infiltration.

[Serum bone marker measurements in bone metabolism disorders associated with inflammatory bowel diseases]

Patients with inflammatory bowel disease (IBD) have decreased bone mineral density (BMD), which is usually much more remarkable in patients with Crohn's disease (CD) than those with ulcerative colitis (UC). The aim of the present study was to investigate the usefulness of serum beta-Crosslaps (bCL) and osteocalcin (OC) determinations to assess bone metabolism in patients with IBD. Forty-nine patients with IBD (23 UC, 26 CD) and 46 healthy controls were studied. Serum bCL and OC were measured by Elecsys immunoassay. Compared to controls (0.275 +/- 0.14 ng/ml) the mean bCL concentration was significantly higher in the CD (mean = 0.489 +/- 0.25 ng/ml; p < 0.001) and UC groups (mean = 0.439 +/- 0.3 ng/ml; p < 0.01). The mean OC concentration was significantly higher in the CD group (28.52 +/- 14.75 ng/ml) than in controls (21.42 +/- 7.43 ng/ml) but OC level was not significantly increased in the UC group (24.89 +/- 15.08 ng/ml). There was no significant difference in bCL or OC concentrations between the CD and UC groups. These results indicate that the accelerated bone resorption is not associated with increased bone formation in patients with IBD. These two marker of the bone metabolism could be a good laboratory parameter of bone pathology in patients with IBD, especially in CD.

Interaction of Dithane M-45 (mancozeb) and lead acetate during a teratogenicity test in rats

The teratogenic effects of lead acetate (Trial 1) and the possible teratogenic effect of this compound administered in combination with a fungicide containing 80% mancozeb (Trial 2) were studied in rats. The test substances were administered by gavage on Days 6-15 of gestation. In Trial 1, five groups were treated with lead acetate administered at doses of 0.1, 0.5, 1.0, 10.0 and 1000.0 mg/kg body weight (bwkg), respectively. In Trial 2, lead acetate was applied at doses of 0.1, 10.0 and 1000.0 mg/bwkg, respectively. In the latter case the dose of the pesticide was 750 mg/bwkg in all treated groups. Lead acetate was not teratogenic after a single administration. Combined administration of lead acetate and mancozeb gave rise to the following toxic effects: average maternal weight decreased during pregnancy, the ratio of live fetuses decreased after the two lowest doses, and fetal mortality increased in the lowest and in the highest dose groups. The ratio of fetal resorption was higher in all the treated groups than in the control group. A significant decrease occurred in average fetal and placental weight in each treated group as compared to the control. Maternal toxicity was expressed in paralysis of the hindlimbs in the two lowest dose groups. Maternal mortality was between 16.7 and 23.3% at the three dose levels. Phocomelia and hernia cerebri occurred as characteristic fetal developmental anomalies in all the treated groups. It is concluded that the joint administration of lead acetate and a mancozeb-containing fungicide can cause maternal toxicity, embryotoxicity and characteristic teratogenic effects.

Effect of immersion fluid temperature on the chicken embryo in teratogenicity tests: short communication

The influence of immersion fluid temperature on the development of the chicken embryo was studied on the day most commonly used for treating incubated eggs in teratological trials. Embryonated eggs were immersed in tap water for 30 min on the 12th day of incubation at 22-25 degrees C or at incubation temperature without a waiting time or after 30 min. The incubation was then continued and the eggs were processed on day 19 of the incubation period. Treatment of eggs at 22-25 degrees C caused a significant increase in embryonic mortality, while the 30-min waiting time did not exert an influence on embryogenesis.

Teratogenicity testing of dimethoate containing insecticide formulation (BI 58 EC) in chicken embryos

BI 58 EC insecticide formulation was tested for teratogenicity in chicken embryos after the treatment of embryonated eggs. The pesticide was diluted in water to 0.8% concentration level, and the emulsion was injected into air space in a volume of 0.1 ml/egg or hen eggs were treated by the immersion technique. The morphological examinations were done on the days 13, 15 and 19 of incubation of chicken embryos. BI 58 EC produced an increased embryo mortality after the treatment which was the most expressive on day 15 of incubation. The trend of embryo weight showed similarity in the control and treated groups after both treatments. The developmental anomalies were sporadic and dose-effect dependency was not seen. Light microscopic findings exhibited a degenerative change in the liver tissue of both treated groups. In summary, the 38% dimethoate containing pesticide formulation (BI 58 EC) was toxic to the developing embryo at 0.8% concentration in our study.

Regional distribution and developmental changes of GluR1-flop protein revealed by monoclonal antibody in rat brain

From immunizations of mice with a glutathione S-transferase fusion protein containing residues 724-781 of the alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor subunit GluR1-flop, two monoclonal antibodies (mAbs) were developed that differed widely in their ranges of specificity. In immunocytochemical and immunoblotting assays performed on COS-7 cells transfected with one of the eight GluR1-4-flip/flop forms, mAb 19B10 recognized all eight forms, whereas mAb 8E11 was specific for GluR1-flop. By means of synthetic peptides, the epitopes were determined to be NKWWYDKG (GluR1-flop760-767) for mAb 19B10 but GSALRNPVN (GluR1-flop740-748) plus a partial epitope, QGLL (GluR1-flop757-760), for mAb 8E11. Further analysis on synthetic peptides pointed to a potential cross-reactivity of mAb 8E11 with GluR2-4-flop variants that lacked editing at the R/G site. The contribution of such cross-reactivities in histoblot labeling patterns on adult rat brain material, however, was judged to be negligible. Histoblot patterns with mAb 8E11 were dominated by strong immunoreactivity in CA1 strata radiatum and oriens and in the dentate molecular layer, whereas the CA3 region was virtually free of labeling. This pattern and those observed at different stages of postnatal development were generally similar to regional distribution patterns previously reported in the literature for GluR1-flop transcripts. Key Words: Glutamate receptors-AMPA receptor subunits-Alternative splicing-Developmentally regulated expression-R/G site.

Cyclosporin and sulfasalazine combination in the treatment of early rheumatoid arthritis

The aim of the study was to assess the efficacy of a new formulation of cyclosporin-A (CyA) and sulfasalazine (SASP) combination treatment in preventing disability and reducing inflammatory disease activity in patients with early rheumatoid arthritis, as well as to assess the tolerability, safety, and suitability for long-term treatment. Forty five patients with early, active rheumatoid arthritis, (RA) were treated with CyA and SASP combination therapy for 12 months. The patients were evaluated by disease activity and radiologic measurements. The combined CyA and SASP therapy seems to be effective. Disease activity parameters improved within 3 months. The individual treatment response rate according to EULAR response criteria was 78% after a one year treatment period. Five patients were withdrawn due to gastrointestinal side effect and two patients because of lack of efficacy. CyA and SASP combination treatment seems to be effective in early severe RA, and with careful monitoring, side effects can be kept under control.

Differential changes in the subcellular distribution of alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate and N-methyl-D-aspartate receptors in neonate and adult rat cortex

We compared the distribution of alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA) receptors and their individual subunits in synaptosomal and microsomal fractions prepared from 2-day-old (P2) and adult rat cortex. In P2 cortex more [3H]-(S)-fluorowillardiine ([3H]FW) binding to AMPA receptors was in the intracellular microsomal fraction than in the synaptosomal fraction whereas in adult rats the reverse was observed. Immunoblots with GluR1, GluR2/3, GluR4 and pan-AMPA antibodies showed the same profile. In contrast, the majority of [3H]MK-801 binding to the N-methyl-D-aspartate (NMDA) receptor and NR1 subunit immunoreactivity was present in the synaptosomal fraction at both developmental time points. These results suggest a developmental rearrangement of the distribution of AMPA receptors within neurons, a process which is likely to be important in synaptic stabilization and plasticity.

Model field study of Sumithion 50 EC and Fusilade S on pheasants

Toxicological studies on wild animals play an important role in the ecotoxicological examination of pesticides. The applied model tests enable the assessment of toxicological consequences with particular regard to the life and nutrition of wild animals in the ploughed field among plants treated with pesticides. The application of different pesticide formulations on plough-land may pose a simultaneous chemical burden to wild birds. In this model study, manifestations of the interaction between an insecticide and a herbicide were studied in pheasants. The birds were placed on lucerne in cages (48 m2) and sprayed once. The applied doses were: Sumithion 50 EC 1 litre/ha + Fusilade S 6 litres/ha (practical doses) and Sumithion 50 EC 5 litres/ha + Fusilade S 30 litres/ha. The analytically determined pesticide concentration of the lucerne was taken as a basis in the further treatment of fodder. The fodder of pheasants contained the following chemicals: 85 mg/kg Sumithion 50 EC + 510 mg/kg Fusilade S and 425 mg/kg Sumithion 50 EC + 2250 mg/kg Fusilade S. Sporadic deaths observed among the pheasants were of traumatic origin and not due to a toxic effect. The decrease of body weight was significant only at the higher dose levels. Acetylcholinesterase (AChE) activity of the blood decreased significantly in both dose groups. On the basis of the results obtained it can be established that at the dose level used in the practice the pesticides studied do not give rise to a toxic interaction in pheasants.

Embryonic toxicity of insecticide Sumithion 50 EC and herbicide Fusilade S in pheasants after individual or combined administration

The purpose of this work was to determine the individual and combined effects of insecticide Sumithion 50 EC (50% fenitrothion) and herbicide Fusilade S (12.5% fluazifop-P-butyl) on the development of pheasant embryos. Eggs were treated by injection of various concentrations of pesticides into the air space on day 12 of incubation. Pathological examination of embryos was carried out on day 23 of the hatching period. Mortality rate, body weight data and morphological alterations were evaluated after the macroscopic examination. The skeletal staining method was used to detect deformities. The two pesticides used in combination moderated the toxic/teratogenic effects of individual treatment.

Surface expression and metabolic half-life of AMPA receptors in cultured rat cerebellar granule cells

The surface expression and metabolic turnover time of alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate (AMPA) receptors are important factors in determining the involvement of these proteins in synaptic function. We used the membrane-impermeant chemical crosslinking reagent BS3 and subsequent immunoblot analysis to show that a large proportion of each of the AMPA receptor subunits GluR1-4 is surface expressed in cultured rat cerebellar granule cells. The apparent molecular mass of the individual subunits was 105 kDa and the surface expressed crosslinked complex was 530 kDa for each of the antibodies tested. These results are consistent with functional ionotropic glutamate receptors being pentameric subunit assemblies. We investigated the time course of AMPA receptor surface expression using the membrane-impermeant biotinylating agent NHS-SS-biotin. The half-life of surface expressed AMPA receptors was found to be 30 h. To estimate the mean degradation rate of AMPA receptors and total trichloracetic acid (TCA)-precipitable protein we used [35S]methionine/cysteine pulse-chase labelling. The half-life of AMPA receptors immunoprecipitated with anti-GluR1 antibody was approximately 48 h and the half-life of total TCA-precipitable protein from the same samples was 37 h.

Assembly intracellular targeting and cell surface expression of the human N-methyl-D-aspartate receptor subunits NR1a and NR2A in transfected cells

The intracellular trafficking, assembly, and cell surface targeting of the human N-methyl-D-aspartate receptor subunits NR1a and NR2A has been studied using both transiently and permanently transfected mammalian cell lines. The expression of either NR1a or NR2A alone does not result in significant cell surface expression of either subunit as determined by cell surface biotinylation and immunofluorescence staining. When NR1a is expressed alone large intracellular accumulations of the subunit are formed which do not co-localize with the golgi apparatus markers protein p58 and wheat germ agglutinin, but do co-localize with the endoplasmic reticulum marker calreticulin. Co-expression of NR1a and NR2A results in a reduction of these intracellular accumulations and the appearance of both subunits on the cell surface. Immunoprecipitation of NR1a from in vitro translated subunit proteins showed that NR2A could only be immunoprecipitated with NR1a when both subunits were co-synthesized in the presence of microsomes. When cells expressing NR1a and NR2A were incubated with [35S]methionine in the presence of Brefeldin-A, a drug which prevents protein transport from the endoplasmic reticulum, NR2A could be immunoprecipitated by an antiserum specific for NR1a. Together these results suggest that the NMDA receptor subunits are assembled in the endoplasmic reticulum and that co-synthesis of the subunits is necessary for their association and their successful cell surface targeting.

Value of different serological tests in the diagnosis of bovine brucellosis in the Amazonian region

The high prevalence of brucellosis is one of the most serious animal health problems affecting cattle and buffalo herds of the Amazonian region. Modern diagnostic methods are not used or not even known, and thus test results are not available in that region. Therefore, in this study a total of 878 selected sera were subjected to comparative examination by five different serological tests (buffered plate agglutination test, tube agglutination test, complement fixation test, indirect ELISA, competitive ELISA). Indirect ELISA gave the highest number of positive results, except in samples derived from the Marajó island, for which the competitive ELISA proved to be the most sensitive. The sensitivity of the classical tests (agglutination, complement fixation) was markedly lower than that of the two ELISAs. After vaccination of 2-month-old heifer calves with the B19 vaccine, all tests showed a 50-60% seropositivity, which disappeared within four months.

Eradication of brucellosis from a cattle herd in the Amazonian region (short communication)

The authors intend to elaborate a brucellosis eradication program which could be used in the Amazonian region, an area characterised by extremely extensive animal husbandry practices. Under such conditions, eradication by selection is the only feasible approach. Brucellosis has been successfully eradicated from a herd with 22.1% prevalence of infection by two serological surveys using an indirect ELISA and the complement fixation test.

[Molecular biological studies on patients with nephrogenic diabetes insipidus]

Nephrogenic diabetes insipidus is a rare, mostly X-linked recessive disorder characterised by renal tubular resistance to the antidiuretic effect of arginine vasopressin. The gene responsible for the X-linked nephrogenic diabetes insipidus, the G-protein-coupled vasopressin V2-receptor, has been localised on the Xq28 region. In this study four patients were investigated with molecular genetic methods. Diagnosis was based on clinical symptoms and lack of increase of urinary osmolality after administration of the arginine vasopressin, or the synthetic vasopressin analogue DDAVP. Three different mutations (C112R, N317K, W323S) were found in three patients, while no mutation was detected in the fourth patient. Since earlier histiocytosis X has been diagnosed in this patient, this patient has probably central diabetes insipidus. Although the main symptoms of the disease can be found in all patients, there are significant differences in the seriousness of the symptoms as well as in some other symptoms. The explanations might be the different mutations in the V2-receptor gene and the various other genetic and environmental factors; these findings provide further evidence that X-linked nephrogen diabetes insipidus results from defects in the V2-receptor gene.

[Systemic mastocytosis]

The systemic mastocytosis is a rare disorder, however, the authors recently diagnosed two cases causing diagnostic problems. The diagnosis was proved by bone marrow biopsy in both patients. The authors review the diagnostic pathway considering the pitfalls. According to their conclusion, the most important factor in the diagnosis of systemic mastocytosis is to think of the possibility of systemic mastocytosis.

Isoforms of endoplasmic reticulum Ca(2+)-ATPase are differentially expressed in normal and diabetic islets of Langerhans

Glucose-dependent sequestration of Ca2+ into endoplasmic reticulum and its subsequent release play an important role in the control of intracellular Ca2+ concentration, which regulates insulin secretion in pancreatic beta-cells. The active uptake of cytosolic Ca2+ into endoplasmic reticulum is mediated by sarco-(endo)plasmic reticulum Ca(2+)-ATPases (SERCAs). We found, using RT-PCR with isoform-specific primers, that SERCA 2 and SERCA 3 mRNAs are co-expressed in human and rat islets of Langerhans and in the RINm5F beta-cell line. Immunochemical analysis also revealed the existence of two SERCA proteins with molecular masses of 110 and 115 kDa in beta-cell membranes. The 115 kDa protein was identified as SERCA 2b by its reaction with an isoform-specific antibody and the 110 kDa protein most probably corresponds to SERCA 3. The presence of two functionally different SERCA isoforms raises the possibility that they are located in distinct Ca2+ stores. There is evidence that altered Ca2+ handling in the beta-cell may contribute to the decreased insulin secretion seen in non-insulin dependent diabetes mellitus (NIDDM). We therefore investigated SERCA 2 and SERCA 3 mRNA expression by quantitative RT-PCR in islets prepared from Goto-Kakizaki (GK) rats, a non-obese spontaneous model of NIDDM. We found a significant reduction (about 68%) in SERCA 3 isoform expression. Since SERCA 2 expression was not significantly reduced, these genes are independently regulated and probably play distinct roles in islets of Langerhans. The marked decrease of SERCA 3 expression may constitute a defect in Ca2+ signalling in GK rat islets which could be a component of NIDDM.

Therapy with pulsed electromagnetic fields in aseptic loosening of total hip protheses: a prospective study

Aseptic loosening is the most common problem of hip arthroplasties, limiting its long term success. We report a study of pulsed electromagnetic field (PEMF) treatment in 24 patients with this complication. At the end of treatment, six months and one year later, pain and hip movements improved significantly with the exception of flexion and extension. There was significant improvement in both isotope scans and ultrasonography, but not in plain X-ray. The decreased pain and improved function suggest that PEMF is effective in improving symptoms of patients with loose hip replacement. No improvement, however, can be expected in patients with severe pain due to gross loosening.

[Advanced-stage ankylosing spondylitis in a subject in the 8th century]

Paleopathological study of an adult male skeleton, coming from a Hungarian archeological site from the 8th century, revealed lesions of the spine (ankylosing vertebral syndesmophytosis, costo-vertebral ankylosis, discal calcifications), of the sacro-iliacs (bilateral ankylosis) and several extraspinal changes (abnormalities of symphysis pubis, enthesopathies). Radiological and CT investigations confirmed the diagnosis of advanced stage ankylosing spondylitis.

Characterization, cell-surface expression and ligand-binding properties of different truncated N-terminal extracellular domains of the ionotropic glutamate receptor subunit GluR1

To identify the location of the first transmembrane segment of the GluR1 glutamate receptor subunit artificial stop codons have been introduced into the N-terminal domain at amino acid positions 442, 510, and 563, namely just before and spanning the proposed first two transmembrane regions. The resultant truncated N-terminal fragments of GluR1, termed NT1, NT2, and NT3 respectively were expressed in Cos-7 cells and their cellular distribution and cell-surface expression analysed using an N-terminal antibody to GluR1. All of the fragments were fully glycosylated and were found to be associated with cell membranes but none was secreted. Differential extraction of the cell membranes indicated that both NT1 and NT2 behave as peripheral membrane proteins. In contrast NT3, like the full subunit, has integral membrane protein properties. Furthermore only NT3 is expressed at the cell surface as determined by immunofluorescence and cell-surface biotinylation. Protease protection assays indicated that only NT3 had a cytoplasmic tail. Binding studies using the selective ligand [(3)H]alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate ([(3)H]AMPA) demonstrated that NT3 does not bind ligand. Together these results indicate that the first transmembrane domain of the GluR1 subunit lies between residues 509 and 562, that the N-terminal domain alone cannot form a functional ligand-binding site and that this domain can be targeted to the cell surface provided that it has a transmembrane-spanning region.

A unique combination of plasma membrane Ca2+-ATPase isoforms is expressed in islets of Langerhans and pancreatic beta-cell lines

Changes in free intracellular Ca2+ concentration regulate insulin secretion from pancreatic beta-cells. The existence of steep Ca2+ gradients within the beta-cell requires the presence of specialized Ca2+ exclusion systems. In this study we have characterized the plasma membrane Ca2+-ATPases (PMCAs) which extrude Ca2+ from the cytoplasm. PMCA isoform- and subtype-specific mRNA expression was investigated in rodent pancreatic alpha- and beta-cell lines, and in human and rat islets of Langerhans using reverse-transcription PCR with primers flanking the calmodulin-binding region of rat PMCA. The expression pattern of PMCA 1 and 2 was conserved in different species and islet-cell types since both rat and human islets of Langerhans and all cell lines tested contained the 1b and 2b forms. PMCA 4 isoform subtypes, however, were expressed in a cell-type-specific manner since beta-cells expressed PMCA 4b only, whereas in islets of Langerhans, which contain alpha, beta, delta and polypeptide-secreting cells, PMCA 4a and 4b were simultaneously present. No evidence was obtained for the expression of PMCA 3. Characterization of the beta-cell Ca2+-pump protein showed that it shared several similarities with the erythrocyte PMCA. It is a P-type ATPase; its phosphorylated intermediate was stabilized by La3+; it reacted with a PMCA-specific antibody; and it was not N-glycosylate. However, the beta-cell PMCA had a higher molecular mass than that of the erythrocyte; this difference could be explained by either predominant translation of the PMCA2 form, which has a molecular mass 3-8 kDa higher than the erythrocyte PMCA 1 and 4 proteins, or by a possible sequence insertion. Thus a unique combination of functionally distinct PMCA isoforms (1b, 2b, 4b) participates in Ca2+ homoeostasis in the beta-cell.

Cell surface expression of the human N-methyl-D-aspartate receptor subunit 1a requires the co-expression of the NR2A subunit in transfected cells

Cell surface expression of the NR1a subunit has been examined in mouse L cell lines permanently transfected with the complementary DNA for human NR1a or with the complementary DNAs for NR1a and NR2A. The expression of the subunits was under the control of the murine mammary tumour virus promoter and following induction of expression by dexamethazone both cell lines expressed high levels of the NR1a subunit as determined by immunofluorescence using permeabilized cells and immunoblotting of cell membranes with subunit specific antibodies. However, cell surface expression of the NR1a subunit was found only in the cells expressing both the NR1a and NR2A subunits. This was confirmed by cell surface biotinylation of the two cell lines and affinity isolation of the receptor subunits. To determine if this result was solely due to the use of a particular cell line and or the choice of expression vector, Cos-7 cells were transiently transfected with either NR1a or NR1a plus NR2A. Here too cell surface expression was only found following co-transfection of both subunits.

Toxicity of the herbicides Flubalex, Fusilade S and Maloran 50 WP to chicken embryos after administration as single compounds or in combination

The teratogenic effects of three herbicides (Flubalex, Fusilade S and Maloran 50 WP) were studied in chicken embryos. Each of the three test substances was administered on days 0 and 12 of incubation. Treatment was followed by evaluation on day 19. The compounds were injected into the air-chamber of eggs at three different concentrations. The medium concentration corresponded to that usually applied in chemical plant protection. In order to determine the combined toxicity of the three herbicides, the medium concentration of Maloran 50 WP and three different concentrations of Flubalex of Fusilade S each were administered simultaneously at a final volume of 0.1 ml per egg, at similar times. Evaluation was done on day 19. In tests of individual toxicity, after injection on day 0 of incubation Maloran 50 WP and Flubalex caused a significant reduction in body mass, while Maloran 50 WP and Fusilade S resulted in marked embryonic mortality. After injection on day 12, the medium and the highest concentration of Flubalex and the highest concentration of Fusilade S caused a marked increase in embryonic mortality. The developmental anomalies were of sporadic nature: their incidence increased only after Flubalex treatment, irrespective of the time of administration. The combined administration of Maloran 50 WP and Flubalex on day 0 resulted in a significant or marked body mass reduction in all groups. Embryonic mortality increased substantially after treatment with the highest dose of Flubalex, while all three concentrations of the other two herbicides led to similar results. When treatment was performed on day 12, the two highest concentrations of Flubalex and the highest concentration of Fusilade S caused expressed embryonic mortality. The developmental anomalies did not show a dose-dependent effect in any of the test series.

High-resolution immunogold localization of AMPA type glutamate receptor subunits at synaptic and non-synaptic sites in rat hippocampus

The cellular and subcellular localization of the GluRA, GluRB/C and GluRD subunits of the alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) type glutamate receptor was determined in the rat hippocampus using polyclonal antipeptide antibodies in immunoperoxidase and immunogold procedures. For the localization of the GluRD subunit a new polyclonal antiserum was developed using the C-terminal sequence of the protein (residues 869-881), conjugated to carrier protein and absorbed to colloidal gold for immunization. The purified antibodies immunoprecipitated about 25% of 3[H]AMPA binding activity from the hippocampus, cerebellum or whole brain, but very little from neocortex. These antibodies did not precipitate a significant amount of 3[H]kainate binding activity. The antibodies also recognize the GluRD subunit, but not the other AMPA receptor subunits, when expressed in transfected COS-7 cells and only when permeabilized with detergent, indicating an intracellular epitope. All subunits were enriched in the neuropil of the dendritic layers of the hippocampus and in the molecular layer of the dentate gyrus. The cellular distribution of the GluRD subunit was studied more extensively. The strata radiatum, oriens and the dentate molecular layer were more strongly immunoreactive than the stratum lacunosum moleculare, the stratum lucidum and the hilus. However, in the stratum lucidum of the CA3 area and in the hilus the weakly reacting dendrites were surrounded by immunopositive rosettes, shown in subsequent electron microscopic studies to correspond to complex dendritic spines. In the stratum radiatum, the weakly reacting apical dendrites contrasted with the surrounding intensely stained neuropil. The cell bodies of pyramidal and granule cells were moderately reactive. Some non-principal cells and their dendrites in the pyramidal cell layer and in the alveus also reacted very strongly for the GluRD subunit. At the subcellular level, silver intensified immunogold particles for the GluRA, GluRB/C and GluRD subunits were present at type 1 synaptic membrane specializations on dendritic spines of pyramidal cells throughout all layers of the CA1 and CA3 areas. The most densely labelled synapses tended to be on the largest spines and many smaller spines remained unlabelled. Immunoparticle density at type 1 synapses on dendritic shafts of some non-principal cells was consistently higher than at labelled synapses of dendritic spines of pyramidal cells. Synapses established between dendritic spines and mossy fibre terminals, were immunoreactive for all studied subunits in stratum lucidum of the CA3 area. The postembedding immunogold method revealed that the AMPA type receptors are concentrated within the main body of the anatomically defined type 1 (asymmetrical) synaptic junction. Often only a part of the membrane specialization showed clustered immunoparticles. There was a sharp decrease in immunoreactive receptor density at the edge of the synaptic specialization. Immunolabelling was consistently demonstrated at extrasynaptic sites on dendrites, dendritic spines and somata. The results demonstrate that the GluRA, B/C and D subunits of the AMPA type glutamate receptor are present in many of the glutamatergic synapses formed by the entorhinal, CA3 pyramidal and mossy fibre terminals. Some interneurons have a higher density of AMPA type receptors in their asymmetrical afferent synapses than pyramidal cells. This may contribute to a lower activation threshold of interneurons as compared to principal cells by the same afferents in the hippocampal formation.

Identification of functional ionotropic glutamate receptor proteins in pancreatic beta-cells and in islets of Langerhans

The presence of ionotropic glutamate receptor proteins in islets of Langerhans and pancreatic beta-cell lines (MIN6, HIT T15, RINm5F) was investigated. For this purpose immunoblot analysis of beta-cell membranes was performed with subunit-specific antibodies. We identified NMDAR1 subunits of the NMDA and KA-2 subunits of the kainate receptors, but did not detect GluR1 subunits of the AMPA receptor. The receptor subunits present were shown to be glycosylated. beta-cell membranes contained specific binding sites for glutamate receptor ligands, and NMDA increased insulin secretion. These results demonstrate that ionotropic glutamate receptor proteins, similar to those in the central nervous system, are expressed in rat pancreatic beta-cells.

Characterisation of endoplasmic reticulum and plasma membrane Ca(2+)-ATPases in pancreatic beta-cells and in islets of Langerhans

We have investigated the plasma membrane (PMCA) and endoplasmic reticulum (SERCA) Ca(2+)-ATPases involved in active transport of Ca2+ in pancreatic beta-cell lines (MIN6, HIT T15, RINm5F) and in islets of Langerhans. Under selective membrane phosphorylation conditions (at low ATP concentration, in the presence of Ca2+ and La3+ and in the absence of Mg2+ at 4 degrees C) the only labelled proteins are the phosphoenzyme intermediates of the Ca(2+)-ATPases. Under these conditions, beta-cell membranes incorporated 32P from [gamma-32P]ATP into two proteins with molecular mass on acidic SDS-polyacrylamide gels of around 115 and 150 kDa. The 150 kDa band was identified as PMCA (i) by reaction with a monoclonal anti-human erythrocyte plasma membrane Ca(2+)-ATPase antibody; (ii) by its typical tryptic cleavage pattern which generated an 80 kDa band; (iii) by lack of inhibition of its autophosphorylation by SERCA-specific inhibitors. The 115 kDa band was identified as SERCA (i) by reaction with a polyclonal anti-rat fast skeletal muscle Ca(2+)-ATPase antibody; (ii) by the concentration-dependent inhibition of its autophosphorylation by thapsigargin and 2,5-di(t-butyl)-1,4-benzohydroquinone (tBHQ), which are specific inhibitors of SERCA. The 115 kDa band was further characterised as the SERCA-2b isoform by reaction with a polyclonal rabbit antibody against the 12 C-terminal amino acids of SERCA-2b.

The cisternal organelle as a Ca(2+)-storing compartment associated with GABAergic synapses in the axon initial segment of hippocampal pyramidal neurones

The axon initial segment of cortical principal neurones contains an organelle consisting of two to four stacks of flat, membrane-delineated cisternae alternating with electron-dense, fibrillar material. These cisternal organelles are situated predominantly close to the synaptic junctions of GABAergic axo-axonic cell terminals. To examine the possibility that the cisternal organelle is involved in Ca2+ sequestration, we tested for the presence of Ca(2+)-ATPase in the cisternal organelles of pyramidal cell axons in the CA1 and CA3 regions of the hippocampus. Electron microscopic immunocytochemistry using antibodies to muscle sarcoplasmic reticulum ATPase revealed immunoreactivity associated with cisternal organelle membranes. The localisation of Ca(2+)-ATPase in cisternal organelles was also confirmed by enzyme cytochemistry, which produced reaction product in the lumen of the cisternae. These experiments provide evidence for the presence of a Ca2+ pump in the cisternal organelle membrane, which may play a role in the sequestration and release of Ca2+. Cisternal organelles are very closely aligned to the axolemma and the outermost cisternal membrane is connected to the plasma membrane by periodic electron-dense bridges as detected in electron micrographs. It is suggested that the interface acts as a voltage sensor, releasing Ca2+ from cisternal organelles upon depolarisation of the axon initial segment, in a manner similar to the sarcoplasmic reticulum of skeletal muscle. The increase in intra-axonal Ca2+ may regulate the GABAA receptors associated with the axo-axonic cell synapses, and could affect the excitability of pyramidal cells.