Learning curve and functional outcomes after laser enucleation of the prostate for benign prostate hyperplasia according to surgeon's caseload.

PURPOSE: To evaluate the impact of surgical caseload on safety, efficacy, and functional outcomes of laser enucleation of the prostate (LEP) applying a structured mentoring program. METHODS: Patient characteristics, perioperative data, and functional outcomes were analyzed descriptively. Linear and logistic regression models analyzed the effect of caseload on complications, functional outcomes and operative speed. Within the structured mentoring program a senior surgeon was present for the first 24 procedures completely, for partial steps in procedures 25-49, and as needed thereafter. RESULTS: A total of 677 patients from our prospective institutional database (2017-2022) were included for analysis. Of these, 84 (12%), 75 (11%), 82 (12%), 106 (16%), and 330 patients (49%) were operated by surgeons at (A) < 25, (B) 25-49, (C) 50-99, (D) 100-199, and (E) ≥ 200 procedures. Preoperative characteristics were balanced (all p > 0.05) except for prostate volume, which increased with caseload. There was no significant difference in change of IPSS, Quality of life, ICIQ, pad usage, peak urine flow, residual urine, and major complications (Group A: 8.3 to E: 7.6%, p = 0.2) depending on the caseload. Caseload was not associated (Odds ratio: 0.7-1.4, p > 0.2) with major complications in the multivariable logistic regression model. Only operating time was significantly shorter with increasing caseload in the multivariable analysis (111-55 min, beta 23.9-62.9, p < 0.001). CONCLUSION: With a structured mentoring program, the safety and efficacy of LEP can be ensured even during the learning curve with very good outcome quality. Only the operating time decreases significantly with increasing experience of the surgeon.

Zonal NephRo Score: external validation for predicting complications after open partial nephrectomy.

PURPOSE: The aim of the study was to externally validate the Zonal NePhRO Score (ZNS) published in 2014 as latest and superior nephrometry score in terms of prediction of perioperative complications and outcome of open partial nephrectomies (OPNs). METHODS: We identified 200 consecutive patients who underwent OPN. Analysis of preoperative CT or MRI scans and retrospective analysis of the patients' clinical records were performed. Tumour complexity was stratified according to the ZNS into three categories: low (4-6), moderate (7-9) and high (10-12) complexity. Predictors for perioperative complications and surgical parameters were identified using univariate and multivariate logistic regression. RESULTS: Tumour complexity was graded in 19.8 % of the cases as low, in 50.3 % as moderate and in 29.9 % as high. In the multivariate analysis, ZNS was significantly associated with a higher complication rate (OR 1.25, 95 % CI 1.04-1.49, p = 0.014), longer ischaemia time (IT) (ß = 1.19, 95 % CI 0.33-2.05, p = 0.007), postoperative drop of estimated glomerular filtration rate (eGFR) (ß = -1.86, 95 % CI -3.71 to -0.01, p = 0.049) and opening of the collecting system (CS) (OR 1.72, 95 % CI 1.40-2.10, p < 0.001). In addition, age and body mass index were identified as independent predictors for complications (OR 1.03, 95 % CI 1.00-1.06, p = 0.043 and OR 1.08, 95 % CI 1.00-1.15, p = 0.031). CONCLUSION: The present study is the first external validation of the ZNS as a predictor of perioperative complications in patients undergoing OPN. A higher ZNS score was associated with a longer IT, a higher rate of opening the CS and drop of eGFR.

Gum acacia mitigates genetic damage in adenine-induced chronic renal failure in rats.

BACKGROUND: Subjects with chronic renal failure (CRF) exhibit oxidative genome damage, which may predispose to carcinogenesis, and Gum acacia (GumA) ameliorates this condition in humans and animals. We evaluated here renal DNA damage and urinary excretion of four nucleic acid oxidation adducts namely 8-oxoguanine (8-oxoGua), 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG), 8-oxoguanosine (8-oxoGuo) and 8-hydroxy-2-deoxyguanisone (8-OHdg) in rats with adenine (ADE)-induced CRF with and without GumA treatment. MATERIALS AND METHODS: Twenty-four rats were divided into four equal groups and treated for 4 weeks. The first group was given normal food and water (control). The second group was given normal food and GumA (15% w/v) in drinking water. The third group was fed powder diet containing adenine (ADE) (0·75% w/w in feed). The fourth group was fed like in the third group, plus GumA in drinking water (15%, w/v). RESULTS: ADE feeding induced CRF (as measured by several physiological, biochemical and histological indices) and also caused a significant genetic damage and significant decreases in urinary 8-oxo Gua and 8-oxoGuo, but not in the other nucleic acids. However, concomitant GumA treatment reduced the level of genetic damage in kidney cells as detected by Comet assay and significantly reversed the effect of adenine on urinary 8-oxoGuo. CONCLUSIONS: Treatment with GumA is able to mitigate genetic damage in renal tissues of rats with ADE-induced CRF.

Influence of hepatitis C virus infection and high virus serum load on biliary complications in liver transplantation.

BACKGROUND: Biliary complications (BCs) and recurrent hepatitis C virus (HCV) infection are among the major causes of morbidity and graft loss following liver transplantation. The influence of HCV on BCs has not been definitely clarified. PATIENTS AND METHODS: We performed a retrospective cohort study to analyze risk factors and outcome of post orthotopic liver transplantation (OLT) BCs in 352 liver transplant recipients over 12 years in Munich, Germany (n = 84 with HCV; living donor and re-OLT were excluded). BCs diagnosed with imaging techniques and abnormal liver enzyme pattern, requiring an intervention, were considered. RESULTS: In a multivariate analysis, HCV serostatus and a high pre-and post-surgery HCV RNA serum load were independent risk factors for anastomotic strictures. HCV positivity and BCs alone did not alter graft loss. HCV-positive patients with BCs, however, had a significantly worse graft outcome (P = 0.02). Non-anastomotic strictures, bile leaks, and the number of interventions needed to treat bile leaks led to worse graft outcome in all patients. CONCLUSION: HCV positivity and a high HCV RNA serum load were risk factors for anastomotic strictures. BCs and HCV had an additive effect on graft loss.

The NeuroSAFE frozen section technique during radical prostatectomy - Implementation and optimization of technical aspects in a routine pathology workflow.

BACKGROUND AND AIMS: In prostate cancer patients, application of the NeuroSAFE frozen section technique during radical prostatectomy has been shown to increase the rate of nerve sparing surgery and to improve functional outcome for the patients. The aim of this study is to report on technical and organizational optimization opportunities of the procedure. MATERIAL AND METHODS: All patients submitted to bilateral intraoperative frozen section from January 2018 until December 2020 (n = 452) were retrospectively analyzed and parameters such as turnaround time, staff situation in the laboratory and histologic properties of the tumors were assessed. RESULTS: The median turnaround time per case was 40.3 ( ± 10.5) min. In 2020 the average time needed from accessioning to diagnosis was 38.1 min. Multivariate linear regression suggested that the number of technical assistants/cryotomes (46.1 min vs. 39.13 min; p < 0.001), the place of microscopic examination (43.0 min vs. 38.7 min; p < 0.001) and the presence of a positive margin (38.0 vs. 44.0 min; p < 0.001) were significant influential factors. The turnaround time was independent of the uropathological expertize of the consultant (39.84 min vs. 40.7 min; p = 0.09), the tumor grade (42.3 vs 39.8 min; p = 0.493) and the presence of extraprostatic extension (44.0 vs 39.8 min; p = 0.099). CONCLUSION: The implementation of simple optimization measures in the workflow as well as structured training of all pathology staff involved in the examination leads to a significant increase in the efficiency of the examination while maintaining the same level of resources. The results could thus be a contribution to the broader application of the procedure.

Trial Participation is Not Associated with Better Biochemical Recurrence-free Survival in a Large Cohort of External Beam Radiotherapy-Treated Intermediate- and High-Risk Prostate Cancer Patients.

AIMS: There is a widespread belief that outcomes of cancer patients treated within clinical trials might not be representative of the outcomes obtained within standard clinical settings. We sought to investigate the effect of trial participation on biochemical recurrence (BCR) in localised, D'Amico intermediate- and high-risk prostate cancer patients treated with external beam radiotherapy (EBRT). MATERIALS AND METHODS: We relied on a study population treated with EBRT between January 2001 and January 2021 at a single tertiary care centre, stratified according to trial enrolment. Separate Kaplan-Meier and multivariable Cox regression models tested BCR-free survival at 60 months within intermediate- and high-risk EBRT patients, after adjustment for covariables. Additionally, the analyses were refitted after inverse probability treatment weighting was performed separately for both risk subgroups. RESULTS: Of 932 eligible patients, 635 (68%) and 297 (32%) had intermediate- and high-risk prostate cancer, respectively. Overall, 53% of patients were trial participants. BCR rates were 11 versus 5% (P = 0.27) and 12 versus 14% (P = 0.08) in trial participants versus non-participants for intermediate- and high-risk subgroups, respectively. Differences in patient and clinical characteristics were recorded. Trial participation status failed to reach predictor status in multivariable Cox regression models for BCR in both intermediate-risk (hazard ratio 1.34; 95% confidence interval 0.71-2.49; P = 0.4) and high-risk patients (hazard ratio 1.03; 95% confidence interval 0.45-2.34; P = 0.9). Virtually the same results were recorded in inverse probability treatment weighting cohorts. CONCLUSIONS: Relying on a large cohort of EBRT-treated intermediate- and high-risk patients, no BCR differences were recorded between trial participants and non-participants after accounting for confounders.

[Movember health care initiative 2019: prostate cancer screening at the University Hospital Frankfurt]. / Urologische Prostatakrebsvorsorge im Rahmen der Movember-Gesundheitsinitiative 2019 am Universitätsklinikum Frankfurt.

BACKGROUND: Men die earlier than women in Germany. Men also have impaired access to cancer screening compared to women. OBJECTIVES: Our Movember campaign 2019 at University Hospital Frankfurt (UKF) aimed at improving health care awareness in the context of prostate cancer checkup. MATERIALS AND METHODS: In November 2019, every male employee of the UKF with a minimum age of 45 yrs (or 40 yrs with a first degree relative with prostate cancer) was offered a free prostate cancer checkup. This checkup contained digital rectal examination (DRE), transrectal ultrasound and PSA (prostata-specific antigen) testing. RESULTS: Overall, 121/840 employees (14.4%) participated in the Movember campaign. A first degree relative with prostate cancer was reported in overall by 14% of the participants (n = 17). At least one prior prostate cancer check up had 33%. A total of 2.5% (n = 3) had one prior negative prostate biopsy. Median age was 54 yrs (interquartile range 50-58). Median PSA level was 0.9 ng/ml and median free-PSA 0.3 ng/ml. A suspicious DRE was found in 5% (n = 6). After stratification according to age (≤ 50 yrs vs. > 50 yrs), participants over 50 yrs had a significantly higher PSA level (1.0 ng/ml vs. 0.7 ng/ml, p < 0.01) and had more frequently at least one prior prostate cancer checkup in the past (42.0 vs. 12.1%, p < 0.01). All suspicious DREs were in the cohort > 50 yrs. Overall, 32.2% (n = 39) had at least a suspicious checkup. A total of 3.3% (n = 4) had suspicious PSA levels. 17.4% (n = 21) of the participants had a suspicious PSA ratio (< 20%) only. During follow-up, 6 prostate biopsies were performed, with the detection of one case of intermediate-risk prostate cancer (Gleason 3 + 4, pT3a, pPn1, pNx, R0). CONCLUSION: Overall, 121 employees participated in our Movember Prostate cancer checkup campaign with measurement of the PSA level. Suspicious results were recorded in 32.2%. One employee was diagnosed and successfully treated with an intermediate-risk prostate cancer.

[Metronomic chemotherapy with oral cyclophosphamide : An individual option for the metastatic castration-resistant prostate cancer patient?] / Metronomische Chemotherapie mit oralem Cyclophosphamid : Eine individuelle Option für den metastasierten kastrationsresistenten Prostatakarzinompatienten?

BACKGROUND: Multiple experimental approaches are meanwhile available for progressive metastatic castration resistant prostate cancer (mCRPC) patients after failure of guideline recommended therapy (i. e., chemotherapy and/or hormonal treatment). We evaluated the outcome of metronomic chemotherapy with cyclophosphamide (CY) in combination with low-dose prednisolone. MATERIALS AND METHODS: A total of 14 mCRPC-patients were treated with CY 50 mg/day (plus prednisolone 10 mg/day) between November 2012 and September 2017 after being resistant or unfit for chemotherapy and/or further hormonal treatment. Time to progression and overall survival (OS) were retrospectively determined by using Kaplan-Meier curves. RESULTS: Eight of 14 (57.1%) patients had undergone radical prostatectomy and 2 (14.3%) external beam radiation. All patients had at least three therapy lines and 50% had ≥5 mCRPC therapies. The median time from first diagnosis to mCRPC was 88 months; the median age was 78 years with a median baseline serum prostate-specific antigen (PSA) level of 341 ng/ml. With a median follow-up of 16.4 months, progression-free survival (PFS) was 71, 64, and 43% after 2, 4, and 6 months, respectively. Median OS was 8.1 months. No relevant adverse events occurred. CONCLUSION: Since CY is a well-tolerated medication with partially good clinical tumor control, it seems to be a convenient, individual treatment option in progressive mCRPC patients after failure of guideline recommended therapy.

[Radical prostatectomy in locally advanced prostate cancer]. / Radikale Prostatektomie beim klinisch lokal fortgeschrittenen Prostatakarzinom.

BACKGROUND: Due to an inverse stage migration, the proportion of patients with more aggressive and locally advanced prostate cancer (PCa) has increased over the last few years. The natural history in these patients shows a higher risk of local complications and worse oncologic outcome. OBJECTIVES: To analyze the impact of radical prostatectomy (RP) in patients with locally advanced PCa. MATERIALS AND METHODS: A review of the literature was performed using PubMed and MEDLINE databases focusing on articles addressing locally advanced PCa. RESULTS: Current guidelines recommend local therapy in patients with locally advanced PCa among other treatment options. Thereby no strong evidence favoring radiotherapy or RP is present. Compared to patients without local treatment, RP may improve oncologic outcome and decrease the risk of local complications. Due to more difficult surgery and an increased need of multimodal therapy, higher perioperative morbidity and worse functional outcomes compared to patients with localized PCa are reported. No reliable prospective data indicating a widespread use of neoadjuvant treatment exists. Indication for further adjuvant or salvage therapies depends on pathologic results and postoperative course. CONCLUSIONS: RP is one of the treatment options with good long-term results which can be offered to patients with locally advanced PCa. Nevertheless, patients need to be counselled especially about the worse postoperative functional outcome compared to patients with localized PCa.

Rat brain guanylate cyclase. Purification, amphiphilic properties and immunological characterization.

Soluble guanylate cyclase (GTP pyrophosphate-lyase (cyclizing), EC 4.6.1.2) has been purified to apparent homogeneity from rat brain by chromatography on Blue-Sepharose CL-6B, precipitation with (NH4)2SO4, preparative isoelectric focusing and gel-filtration on Ultrogel AcA-34. On sodium dodecyl sulphate (SDS)-polyacrylamide gel electrophoresis the purified enzyme showed a single band with an apparent molecular weight 59 000, when stored in buffer without glycerol and 2-mercaptoethanol. Purified enzyme has been found to be very unstable; inactivation can however be partially reversed by an endogenous heat-stable activator fraction. A monospecific antiserum obtained by immunization of rabbits was found to precipitate guanylate cyclase. This antibody also reacted with membrane-bound enzyme, indicating a close similarity to the soluble enzyme. Metal divalent cations were in general found to be strong inhibitors of the enzyme activity, though Ca2+ had no effect. ATP, CTP or UTP were shown to be competitive inhibitors of purified guanylate cyclase. Sodium nitroprusside increased cyclic GMP formation by the purified enzyme. Lysophosphatidylcholine and oleic acid, at low concentration, activated guanylate cyclase. Other unsaturated fatty acids, particularly arachidonic acid, dramatically inhibited the enzyme activity. Lipids may regulate the enzyme activity by binding to an apolar domain, as suggested by charge-shift electrophoresis. The mechanism by which guanylate cyclase is regulated in the cell appears to be a complex phenomenon. It may occur through oxidative reductive processes, and/or depend on other effectors, such as triphospho-nucleotides, divalent cations and lipid microenvironment.

Purification and characterization of a nicotinamide deamidase released into the growth medium of neuroblastoma in vitro.

Nicotinamide deamidase (nicotinamide amidohydrolase, EC 3.5.1.19) has been demonstrated in the conditioned growth medium of the M1 clonal cell line of mouse C1300 neuroblastoma. The enzyme has been purified 1200-1500-fold by Sephadex G25, hydroxyapatite, DEAE-cellulose, Sephadex G200 and NAD-Sepharose column chromatographies. The purified protein was characterized by polyacrylamide gel electrophoresis under non-denaturing and denaturing conditions. The apparent molecular weight has been estimated to be 230,000, and the subunits had respective molecular weights of 65,000 and 50,000. Histidine was the only NH2-terminal amino acid found. The enzyme is a glycoprotein; mannose and N-acetyl-glucosamine have been identified. The effects of various ions on its activity have been investigated. The enzyme has a Km for nicotinamide in the order of 10(-6) M, a pH optimum of 7.2 and a pHi of 5.4. It is inhibited by heating and by sulfhydryl reagents. The existence of a nicotinamide deamidase with a high affinity for nicotinamide favors the operation of the Preiss-Handler pathway in M1 cells cultured in vitro. We found an induction of nicotinamide deamidase and a cellular increase of NAD with a higher nicotinamide supply and a repression of the released enzyme with supplying NAD in the nutrition medium of M1 cell cultures.

Purification and characterization of myosin from bovine retina.

Myosin has been isolated from bovine retinae and characterised by its ATPase (ATP phosphohydrolase, EC 3.6.1.3) activity, its mobility in sodium dodecyl sulphate polyacrylamide gels and by electron microscopy. The purified myosin shows high ATPase activity in the presence of EDTA or Ca2+ and a low activity in the presence of Mg2+. The Mg2+-dependent ATPase activity is stimulated by rabbit skeletal muscle actin. The presumptive retinal myosin possesses a major component which has a mobility in sodium dodecyl sulphate polyacrylamide gel electrophoresis similar to that of the heavy chain of bovine skeletal muscle myosin. Electron microscopy showed retinal myosin to form bipolar filaments in 0.1 M KCl. It is concluded that the retina possesses a protein with enzymic and structural properties similar to those of muscle myosin.

Phosphopeptide and phosphoprotein metabolism in brain.

Phosphopeptide and phosphoprotein phosphorylation was studied in rat brain microsomes and rat brain slices which were incubated in the presence of [gamma-32 P] ATP under various experimental conditions. Radioactive phosphoserine was isolated from phosphopeptides and phosphoproteins. Naplus, K+, Mg2+ and cyclic AMP had a stimulating effect on the labelling of phosphopeptides. Ouabain and Ca2+ lowered the level of 32P incorporation into the phosphopeptides. The phosphoproteins behaved similarly to the phosphopeptides except for the potassium effect. Chase experiments showed a faster decrease in the labelling of phosphopeptides than in phosphoproteins. We suggest that both compounds may be involved in active transport phenomena.

Gangliosides and phospholipids of the membranes from bovine adrenal medullary chromaffin granules.

The lipid and ganglioside compositions of membranes of chromaffin granules isolated from bovine adrenal medulla have been investigated. The detailed lipid analysis revealed the presence of high levels of lysophosphatidylcholine, in agreement with previous studies, but also of sphingomyelin and plasmalogens. From these membranes, gangliosides have been extracted and separated by thin-layer chromatography and analysed. 95% of the total recovered gangliosides were hematosides (GM3), which migrated as three major species. Sugar analyses have been performed, as well as the fatty acid compositions. The three hematoside gangliosides appeared to differ on the basis of their fatty acid composition. Compared with the brain, chromaffin granule membranes showed a simple ganglioside composition, thus offering a good model for the study of the metabolism and the role of gangliosides. The simple ganglioside composition of chromaffin granule membranes has allowed us to state that there are 60 mol phospholipid and 30 mol cholesterol per mol ganglioside.

Effects of deoxycholate and phospholipase A2 on choline and ethanolamine phosphotransferases of chicken brain microsomes.

Ethanolamine phosphotransferase (EC 2.7.8.1) and choline phosphotransferase (EC 2.7.8.2) activities were assayed in fresh microsomes from adult chicken brains with either diacylglycerols or alkylacylglycerols. Pretreatment of microsomes with 1.25 mM sodium deoxycholate, a concentration less than the critical micelle concentration, produced a slight inhibition of choline phosphotransferase activity. A deoxycholate concentration (5.0 mM) greater than the critical micelle concentration (3.0 mM) decreased the choline phosphotransferase activity by more than 70% but had no effect on ethanolamine phosphotransferase activity. Inclusion of 1.25 mM deoxycholate in the assay medium decreased choline phosphotransferase activity 35% but increased ethanolamine phosphotransferase activity 50%. The deoxycholate appeared to inactive the choline phosphotransferase. Phospholipase A2 (Vipera russelli) treatments of microsomes removed phosphoglycerides and decreased both phosphotransferase activities to a similar extent. Decreased activities are probably due to disruption of the membrane structure. Choline and ethanolamine phosphotransferase activities are apparently in different enzymes which lack specificity for the type of diglyceride. Thus, the systematic names should include 1,2-diradyl-sn-glycerol instead of 1,2-diacyl-sn-glycerol.

Brain UDPgalactose: ceramide galactosyltransferase Purification of a catalytically active protein obtained after proteolytic digestion.

A procedure for the purification of UDPgalactose--2-hydroxyacylsphingosine galactosyltransferase (EC 2.4.1.45) including detergent extraction, ion-excharge chromatography and proteolytic digestion was developed. The active fraction obtained by this procedure had about 100 times higher specific activity than microsomes. Enzymic activity resisted destruction by pronase treatment at 4 degrees C. Agarose gel chromatography indicated the presence of an enzyme-phospholipid-detergent complex with a molecular weight between 400 000 and 500 000. Intact phospholipids seemed to be required for full enzymic activity as evidenced by the drastic loss of activity upon treatment with phospholipase A or C.

Comparison of the structural characteristics of the 4-aminobutyrate:2-oxoglutarate transaminases from rat and human brain, and of their affinities for certain inhibitors.

4-Aminobutyrate:2-oxoglutarate (4-aminobutyrate:2-oxoglutarate amino-transferase, EC 2.6.1.19) from human brain has been purified 2500-fold with respect to the initial homogenate. The enzyme, which appears to be pure by polyacrylamide gel electrophoresis, N-terminal analysis and immunodiffusion, was compared to rat brain 4-aminobutyrate transaminase, purified to the same extent in an earlier study [15]. The two enzymes, which have approximately the same molecular weight, show large differences in their tryptic fingerprints and in the peptides produced by cyanogen bromide cleavage. The Km values (limit) for 4-aminobutyrate are different, the human enzyme having four times greater affinity for this substrate. A series of branched-chain fatty acids (including n-dipropylacetate), which are structural analogues of 4-aminobutyrate and inhibit rat brain 4-aminobutyrate transaminase, are less powerful inhibitors of the human enzyme.

The nature of DT-diaphorase (EC 1.6.99.2) activity in plasma membrane of astrocytes in primary cultures.

This is the confirmation of an earlier indication (Mersel, M., Malviya, A.N., Hindelang, C. and Mandel, P. (1984) Biochim. Biophys. Acta 778, 144-154) that the plasma membrane of astrocytes in primary cultures is endowed with DT-diaphorase (EC 1.6.99.2) activity. It is observed that the NADPH-2,6-dichloroindophenol diaphorase activity found in the isolated plasma membrane is not inhibited by dicoumarol. DT-diaphorase-type activity is also observed on the cell surface employing dichloroindophenol as external electron acceptor and it is found to be a dicoumarol-sensitive NADH dehydrogenase.

Poly(ADPR)polymerase expression and activity during proliferation and differentiation of rat astrocyte and neuronal cultures.

Poly(ADPR)polymerase (poly(ADPR)P) mRNA and enzymatic activity levels were investigated in primary cultures of rat astrocytes and neurons in the absence or presence of basic fibroblast growth factor (bFGF) and nerve growth factor (NGF), respectively. In cultured rat astrocytes, a biphasic increase in poly(ADPR)P mRNA, associated with enhanced nuclear poly(ADPR)P enzymatic activity, were observed. The first rise in poly(ADPR)P mRNA and enzymatic activity is at the beginning of cell proliferation and the second with the occurrence of cell differentiation. In the presence of bFGF (5 ng/ml) the mRNA peaks and the differentiation-associated poly(ADPR)P enzymatic activity undergoes a 2-fold increase. In neuronal cultures an initial high level of poly(ADPR)P mRNA is followed by a decrease while differentiation is progressively achieved. A limited increase of poly(ADPR)P activity is observed during this phase. In the presence of NGF (50 ng/ml), similar poly(ADPR)P mRNA expression and enzymatic activity patterns are observed. The results suggest that poly(ADPR)P is involved at the onset of nerve-cell proliferation and differentiation.

Plasma membrane isolated from astrocytes in primary cultures. Its acceptor oxidoreductase properties.

Rat astrocytes in primary cultures were employed to isolate the plasma membrane. The method for the isolation of plasma membrane was based on the capacity of the cytoskeleton to adhere to the substratum entrapping intracellular organelles during freezing-thawing cycle performed on the cell. By washing the 'surface adherent framework', the untrapped plasma membrane were recovered and density equilibrium centrifugation resulted in the isolated membrane. The isolated plasma membrane was characterized on the basis of a variety of marker enzymes positive to the plasma membrane such as (Na+ + K+)-ATPase or 5'-nucleotidase as well as the lack of conventional markers of other endomembranes. Ultrastructurally the membranes, as isolated here, were mainly vesicular in nature. The isolated plasma membrane was devoid of the dehydrogenase responsible for NADH-cytochrome c reductase activity. However, NADH-ferricyanide reductase activity and the dehydrogenase system catalyzing the transfer of reducing equivalents from NADH or NADPH to dichloroindophenol seems plasma membrane redox system. The identical specific activity employing dichloroindophenol as an electron acceptor with NADH or NADPH as donor indicate a DT-diaphorase (EC 1.6.99.2) like activity in the astrocytes plasma membrane.