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1.
J Transl Med ; 20(1): 121, 2022 03 14.
Article in English | MEDLINE | ID: mdl-35287672

ABSTRACT

BACKGROUND: Safety, tolerability and efficacy of granulocyte colony-stimulating factor (G-CSF) for mobilization of hematopoietic stem and progenitor cells (HSPCs) from healthy donors have been conclusively demonstrated. This explicitly includes, albeit for smaller cohorts and shorter observation periods, biosimilar G-CSFs. HSPC donation is non-remunerated, its sole reward being "warm glow", hence harm to donors must be avoided with maximal certitude. To ascertain, therefore, long-term physical and mental health effects of HSPC donation, a cohort of G-CSF mobilized donors was followed longitudinally. METHODS: We enrolled 245 healthy volunteers in this bi-centric long-term surveillance study. 244 healthy volunteers began mobilization with twice-daily Sandoz biosimilar filgrastim and 242 underwent apheresis after G-CSF mobilization. Physical and mental health were followed up over a period of 5-years using the validated SF-12 health questionnaire. RESULTS: Baseline physical and mental health of HSPC donors was markedly better than in a healthy reference population matched for ethnicity, sex and age. Physical, but not mental health was sharply diminished at the time of apheresis, likely due to side effects of biosimilar G-CSF, however had returned to pre-apheresis values by the next follow-up appointment after 6 months. Physical and mental health slightly deteriorated over time with kinetics reflecting the known effects of aging. Hence, superior physical and mental health compared to the general healthy non-donor population was maintained over time. CONCLUSIONS: HSPC donors are of better overall physical and mental health than the average healthy non-donor. Superior well-being is maintained over time, supporting the favorable risk-benefit assessment of volunteer HSPC donation. Trial registration National Clinical Trial NCT01766934.


Subject(s)
Hematopoietic Stem Cell Mobilization , Mental Health , Granulocyte Colony-Stimulating Factor/pharmacology , Healthy Volunteers , Hematopoietic Stem Cells , Humans
2.
Eur Rev Med Pharmacol Sci ; 25(1): 390-396, 2021 01.
Article in English | MEDLINE | ID: mdl-33506928

ABSTRACT

OBJECTIVE: For safe implementation and broader application of fecal microbiota transplantation (FMT), quality controlled stool banking is a must. Establishing a stool bank is a complex, time-consuming, and expensive process, making it a real challenge in an Eastern European country. We aimed to establish the first stool bank in Eastern Europe - in Bulgaria. SUBJECTS AND METHODS: A multidisciplinary team of gastroenterologists, microbiologists, infectionists, and geneticists was set up. We used a questionnaire based on the First European FMT Consensus in order to recruit possible stool donors. Laboratory blood and stool tests were performed on all potential donors. RESULTS: Between October 2018 and April 2019, 112 donor volunteers completed a questionnaire; 70 (62.5%) were excluded, mainly because of age above 50, an unhealthy BMI, and risk behavior. Fourty-two (37.5%) donor candidates were invited for laboratory testing of blood and feces, of which 12 (28.6%) passed this screening. Of 12 donors, 4 (33%) failed at the following screening test, which is performed every 3-6 months. Finally, 8 (7.14%) active donors were enrolled. Ten successful FMTs were performed on patients with recurrent Clostridium difficile infection. CONCLUSIONS: Even though we found many healthy volunteers, only a low percentage (7.14%) of them were suitable to become feces donors. Establishing a stool bank in an Eastern European country is essential for making FMT safe and more popular as a treatment method, finding further implementation and regulation of FMT and supporting physicians offering this treatment to their patients.


Subject(s)
Enterocolitis, Pseudomembranous/therapy , Fecal Microbiota Transplantation , Adult , Aged , Bulgaria , Colonoscopy , Europe , Gastrointestinal Microbiome , Humans , Middle Aged , Surveys and Questionnaires , Young Adult
3.
Eur Rev Med Pharmacol Sci ; 24(1): 315-322, 2020 01.
Article in English | MEDLINE | ID: mdl-31957845

ABSTRACT

OBJECTIVE: To study gut barrier function in patients with liver cirrhosis (LC) by evaluating the intestinal permeability (IP) and its relationship with the severity and etiology of the disease. PATIENTS AND METHODS: The study included 31 patients with LC and 25 healthy controls. Child-Pugh score was used for evaluation of the LC severity. IP was assessed by the rise in levels of iohexol, which was administered orally (25 mL, 350 mg/mL) 2 h after breakfast. Three and six hours later serum (SIC mg/L) and urine (UIC g/mol) iohexol concentrations were determined by a validated HPLC-UV technique. RESULTS: Patients with LC had significantly higher mean SIC value compared with control group at 3 h (2.05 ± 1.67 vs. 1.25 ± 1.41 mg/L, p=0.021, as well as at 6 h (2.20 ± 2.65 vs. 1.11 ± 1.06 mg/L, p=0.001) after ingestion. No significant difference was found in mean SIC value of patients at 3 and 6 h. 23% of the patients had an increased IP. The mean iohexol urine recovery of patients was similar to that of the controls both at 3 h and at 6 h. Mean SIC values were significantly higher in patients with advanced Child C class than in healthy controls or the subgroup with Child B class, both at 3 h (2.54 ± 1.95 mg/L vs. 1.11 ± 1.06 mg/L, p=0.007) or (2.57 ± 1.85 mg/L vs. 1.35±1.32 mg/L, p=0.005) and at 6 h (2.57 ± 1.85 mg/L vs. 1.25 ± 1.40 mg/L, p=0.002) or 2.54 ± 1.95 mg/L vs. 1.07 ± 0.35 mg/L, p=0.02). Cirrhotic patients with ascites had significantly higher SIC in comparison with the controls, both at 3 h (2.31 ± 1.74 vs. 1.25 ± 1.41 mg/, p=0.009) and at 6 h (2.20 ± 1.87 vs. 1.11 ± 1.06 mg/l, p=0.007). In the subgroup of patients with alcoholic LC, the mean SIC values at 3 and 6 h (2.29 ± 1.80, 2.33 ± 1.85 mg/L, respectively) were significantly higher (p= 0.016, p=0.003) compared to the control group (1.25 ± 1.41, 1.11 ± 1.06 mg/L, respectively). CONCLUSIONS: Increased IP is found in 23% of cirrhotic patients. Permeability alterations are significantly more pronounced in patients with advanced LC with the presence of ascites and in those with alcoholic etiology.


Subject(s)
Intestinal Diseases/metabolism , Iohexol/analysis , Liver Cirrhosis/metabolism , Adult , Aged , Female , Healthy Volunteers , Humans , Intestinal Diseases/blood , Intestinal Diseases/urine , Liver Cirrhosis/blood , Liver Cirrhosis/urine , Male , Middle Aged , Permeability
4.
Eur Rev Med Pharmacol Sci ; 23(4): 1661-1667, 2019 Feb.
Article in English | MEDLINE | ID: mdl-30840290

ABSTRACT

OBJECTIVE: We aimed to assess the preoperative rectal cancer angiogenesis with Endorectal Power Doppler Ultrasonography by using the Power Doppler Vascularity Index (PDVI) calculated by imaging analysis software, and to compare it with the microvessel density (MVD) in surgical specimens PATIENTS AND METHODS: This study included 110 patients (39 females; mean age 61.5 years) with rectal cancer. Immunohistochemical staining of surgical specimens with anti-CD-31 antibody was used for MVD evaluation. The PDVI of each tumor was calculated using Endorectal Power Doppler with computer-assisted quantification of colour pixels. RESULTS: Mean MVD - 163 ± 69 microvessels/mm2 (50-328) was used as a cutoff point, differentiating two groups of tumors with high (> 160 mm2) and low (≤ 160 mm2) angiogenic activity. Mean PDVI of 8.9 ± 6.0% (0-27.3) was used as a cutoff point, dividing two groups of tumors with high (> 8%) and low (≤ 8%) PDVI. The MVD and the PDVI showed a good positive correlation (r = 0.438, p = 0.002). Patients with low PDVI had 25 months longer overall survival (p < 0.05) than patients with high PDVI. Patients with low MVD had 36 months longer survival (p < 0.05). CONCLUSIONS: Endorectal Power Doppler Ultrasonography is a reliable and noninvasive method for assessment of the extent of rectal cancer angiogenesis. Tumor angiogenesis assessed by the PDVI correlated with histological MVD determination and could predict survival rates. Endorectal Power Doppler examination is a useful and reproducible method for in vivo preoperative quantitative assessment of tumor vascularization.


Subject(s)
Neovascularization, Pathologic/pathology , Rectal Neoplasms/pathology , Ultrasonography, Doppler , Endosonography , Female , Humans , Middle Aged , Neovascularization, Pathologic/surgery , Prospective Studies , Rectal Neoplasms/surgery , Software
5.
Eur Rev Med Pharmacol Sci ; 23(2): 788-794, 2019 Jan.
Article in English | MEDLINE | ID: mdl-30720187

ABSTRACT

OBJECTIVE: In this study, we aimed to evaluate the role of serum trefoil factor 3 (TFF3) as a biomarker of disease activity in patients with inflammatory bowel disease (IBD) and to compare TFF3 values with those of fecal calprotectin (FC). PATIENTS AND METHODS: 128 patients with IBD were divided into four groups: 1) active ulcerative colitis (UC); 2) quiescent UC; 3) active Crohn's disease (CD); 4) quiescent CD. The serum levels of TFF3 and FC levels were assessed in all patients and 16 controls. RESULTS: Patients with active UC had higher TFF3 levels than those with quiescent UC (p<0.001), those with active (p<0.001) or quiescent CD (p<0.001) and controls (p <0.001). We found a correlation between TFF3 and FC values in patients with active (r = 0.478, p = 0.006) and quiescent UC (r=0.528, p=0.002). TFF3 levels correlated with endoscopic activity in UC (evaluated by UC Endoscopic Index of Severity - UCEIS) (r=0.662, p<0.001). CONCLUSIONS: Serum TFF3 is able to identify patients with active UC. It could be used as a marker to predict disease activity in patients with UC.


Subject(s)
Colitis, Ulcerative/diagnosis , Crohn Disease/diagnosis , Trefoil Factor-3/blood , Adolescent , Adult , Biomarkers/blood , Colitis, Ulcerative/blood , Colitis, Ulcerative/immunology , Colitis, Ulcerative/pathology , Colon/diagnostic imaging , Colon/immunology , Colon/pathology , Colonoscopy , Crohn Disease/blood , Diagnosis, Differential , Feces/chemistry , Female , Humans , Intestinal Mucosa/diagnostic imaging , Intestinal Mucosa/immunology , Intestinal Mucosa/pathology , Leukocyte L1 Antigen Complex/analysis , Male , Middle Aged , ROC Curve , Severity of Illness Index , Young Adult
6.
Ann Oncol ; 29(9): 1903-1910, 2018 09 01.
Article in English | MEDLINE | ID: mdl-30099478

ABSTRACT

Background: The use of supportive granulocyte colony-stimulating factor (G-CSF) to reduce the risk of neutropenic complications in high-risk cancer patients is consistently recommended by several clinical practice guidelines. However, in a previous meta-analysis, G-CSF prophylaxis was associated with an increased risk of secondary malignancies while reducing long-term mortality. We present here an updated systematic review and meta-analysis. Materials and methods: A systematic literature search was carried out to identify randomized controlled trials of cancer patients receiving conventional-dose chemotherapy, assigned to primary G-CSF support or a control group without initial G-CSF, with at least 2 years of follow-up. Studies were categorized into one of the four groups, based on the chemotherapy regimen and study design. An updated meta-analysis was carried out; relative risk (RR) and 95% confidence intervals (CIs) for all-cause mortality and secondary malignancies were calculated. Results: Of 2604 articles screened, 14 eligible studies were identified and combined with studies identified in the previous systematic literature searches. The updated meta-analysis included a total of 68 studies presenting 71 separate comparisons. Survival was significantly improved in patients receiving primary G-CSF support, compared with patients without primary G-CSF support (mortality RR=0.92; 95% CI 0.90-0.95; ARD=-3.3%; 95% CI -4.2--2.4; P < 0.0001). The largest improvement in survival was observed with dose-dense chemotherapy regimens with G-CSF support, compared with controls receiving no G-CSF support (mortality RR=0.86; 95% CI 0.80-0.92; P < 0.0001). Patients who received primary G-CSF support experienced a significantly higher risk of secondary malignancies, compared with controls (RR=1.85; 95% CI 1.19-2.88; ARD=0.47; 95% CI 0.21-0.73; P < 0.01). Conclusions: Our findings demonstrate that overall survival is improved in patients receiving intensified chemotherapy with primary G-CSF support, compared with those receiving standard chemotherapy. Primary G-CSF support was also associated with a higher risk of developing secondary malignancies, including secondary acute myeloid leukemia and myelodysplastic syndrome.


Subject(s)
Antineoplastic Agents/adverse effects , Chemotherapy-Induced Febrile Neutropenia/prevention & control , Granulocyte Colony-Stimulating Factor/administration & dosage , Neoplasms, Second Primary/epidemiology , Neoplasms/drug therapy , Chemotherapy-Induced Febrile Neutropenia/etiology , Granulocyte Colony-Stimulating Factor/adverse effects , Humans , Neoplasms/blood , Neoplasms/mortality , Neoplasms, Second Primary/chemically induced , Practice Guidelines as Topic , Randomized Controlled Trials as Topic , Risk Assessment
7.
Ann Oncol ; 28(9): 2272-2277, 2017 Sep 01.
Article in English | MEDLINE | ID: mdl-28637287

ABSTRACT

BACKGROUND: Following the functional and physicochemical characterization of a proposed biosimilar, comparative clinical studies help to confirm biosimilarity by demonstrating similar safety and efficacy to the reference product in a sensitive patient population. PATIENTS AND METHODS: LA-EP2006 is a proposed biosimilar that has been developed for pegfilgrastim, a long-acting form of granulocyte colony-stimulating factor for the prevention of neutropenia. The current analysis reports data pooled from two independent, multinational, prospective, randomized, controlled, double-blind phase III studies of similar design comparing the safety and efficacy of reference pegfilgrastim with LA-EP2006 in patients with breast cancer receiving myelotoxic (neo)adjuvant TAC (docetaxel, doxorubicin, and cyclophosphamide) chemotherapy and requiring granulocyte colony-stimulating factor. RESULTS: A total of 624 patients were randomized in the PROTECT-1 and PROTECT-2 studies (NCT01735175; NCT01516736) (LA-EP2006: n = 314; reference: n = 310). Baseline characteristics of patients were well balanced across treatment groups. The primary end point, mean duration of severe neutropenia in the first chemotherapy cycle was similar in both the LA-EP2006 and reference groups (1.05 ± 1.055 days versus 1.01 ± 0.958 days), with a treatment difference of - 0.04 days [95% confidence interval (CI): -0.19 to 0.11] that met the equivalence criteria (the 95% CI were within the defined margin of ±1 day). Secondary end points, such as the nadir of absolute neutrophil count and the incidence of febrile neutropenia, were also similar between LA-EP2006 and reference pegfilgrastim. The safety and tolerability profile of LA-EP2006 was similar to that observed with reference pegfilgrastim, and there were no reports of neutralizing antibodies. CONCLUSIONS: This pooled analysis confirms, as a part of totality of evidence approach, that the proposed biosimilar pegfilgrastim LA-EP2006 has a comparable efficacy and safety profile to reference pegfilgrastim in patients with breast cancer receiving TAC chemotherapy. CLINICAL TRIAL NUMBERS: NCT01735175 and NCT01516736.


Subject(s)
Antineoplastic Combined Chemotherapy Protocols/adverse effects , Biosimilar Pharmaceuticals/therapeutic use , Breast Neoplasms/drug therapy , Filgrastim/therapeutic use , Neutropenia/drug therapy , Polyethylene Glycols/therapeutic use , Adult , Biosimilar Pharmaceuticals/adverse effects , Double-Blind Method , Female , Filgrastim/adverse effects , Humans , Neutropenia/chemically induced , Polyethylene Glycols/adverse effects , Prospective Studies , Treatment Outcome
8.
Ann Oncol ; 26(9): 1948-1953, 2015 Sep.
Article in English | MEDLINE | ID: mdl-26122726

ABSTRACT

BACKGROUND: Biosimilars of filgrastim are in widespread clinical use in Europe. This phase III study compares biosimilar filgrastim (EP2006), with the US-licensed reference product, Neupogen(®), in breast cancer patients receiving (neo)adjuvant myelosuppressive chemotherapy (TAC). PATIENTS AND METHODS: A total of 218 patients receiving 5 µg/kg/day filgrastim over six chemotherapy cycles were randomized 1:1:1:1 into four arms. Two arms received only one product (nonalternating), biosimilar or reference, and two arms (alternating) received alternating treatments during each cycle (biosimilar then reference or vice versa). The primary end point was duration of severe neutropenia (DSN) during cycle 1. RESULTS: The baseline characteristics were balanced between the four treatment arms. Noninferiority of biosimilar versus the reference was demonstrated: DSN (days) in cycle 1 was 1.17 ± 1.11 (biosimilar, N = 101) and 1.20 ± 1.02 (reference, N = 103), 97.5% confidence interval lower boundary for the difference was -0.26 days (above the predefined limit of -1 day). No clinically meaningful differences were observed regarding any other efficacy parameter: incidence of febrile neutropenia (FN); hospitalization due to FN; incidence of infections; depth and time of absolute neutrophil count (ANC) nadir and time to ANC recovery during cycle 1 and across all cycles. The pattern and frequency of adverse events were similar across all treatments. CONCLUSION: This study demonstrates that biosimilar and the reference filgrastim are similar with no clinically meaningful differences regarding efficacy and safety in prevention of severe neutropenia. Biosimilar filgrastim could represent an important alternative to the reference product, potentially benefiting public health by increasing access to filgrastim treatment. STUDY NUMBER: NCT01519700.


Subject(s)
Biosimilar Pharmaceuticals/therapeutic use , Filgrastim/analogs & derivatives , Filgrastim/therapeutic use , Neutropenia/prevention & control , Adult , Aged , Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Breast Neoplasms/drug therapy , Double-Blind Method , Female , Granulocyte Colony-Stimulating Factor/therapeutic use , Humans , Middle Aged , Neoadjuvant Therapy , Neutropenia/drug therapy , Young Adult
9.
N Engl J Med ; 344(9): 626-31, 2001 Mar 01.
Article in English | MEDLINE | ID: mdl-11228276

ABSTRACT

BACKGROUND: Low-molecular-weight heparins are frequently used to treat venous thromboembolism, but optimal dosing regimens and clinical outcomes need further definition. METHODS: In this multicenter, open-label study with blinded adjudication of end points, we randomly assigned patients with acute deep-vein thrombosis to one of three treatment regimens: intravenous administration of unfractionated heparin; subcutaneous administration of a low-molecular-weight heparin, reviparin, twice a day for one week; or subcutaneous administration of reviparin once a day for four weeks. The primary end point was evidence of regression of the thrombus on venography on day 21; secondary end points were recurrent venous thromboembolism, major bleeding within 90 days after enrollment, and death. RESULTS: Of the patients receiving unfractionated heparin, 40.2 percent (129 of 321) had thrombus regression, as compared with 53.4 percent (175 of 328) of patients receiving reviparin twice daily and 53.5 percent (167 of 312) of the patients receiving reviparin once daily. With regard to thrombus regression, reviparin administered twice daily was significantly more effective than unfractionated heparin (relative likelihood of thrombus regression, 1.28; 97.5 percent confidence interval, 1.08 to 1.52), as was reviparin administered once daily (relative likelihood, 1.29; 97.5 percent confidence interval, 1.08 to 1.53). Mortality and the frequency of episodes of major bleeding were similar in the three groups. CONCLUSIONS: In acute deep-vein thrombosis, reviparin regimens are more effective than unfractionated heparin in reducing the size of the thrombus. Reviparin is also more effective than unfractionated heparin for the prevention of recurrent thromboembolism and equally safe.


Subject(s)
Anticoagulants/therapeutic use , Heparin, Low-Molecular-Weight/therapeutic use , Heparin/therapeutic use , Pulmonary Embolism/prevention & control , Thromboembolism/prevention & control , Thrombosis/drug therapy , Acute Disease , Anticoagulants/administration & dosage , Anticoagulants/adverse effects , Drug Administration Schedule , Female , Hemorrhage/chemically induced , Heparin/administration & dosage , Heparin/adverse effects , Heparin, Low-Molecular-Weight/administration & dosage , Heparin, Low-Molecular-Weight/adverse effects , Humans , Infusions, Intravenous , Injections, Subcutaneous , Male , Middle Aged , Neoplasms/mortality , Pulmonary Embolism/mortality , Secondary Prevention , Single-Blind Method , Thrombocytopenia/chemically induced
10.
J Hum Hypertens ; 14(6): 347-54, 2000 Jun.
Article in English | MEDLINE | ID: mdl-10878692

ABSTRACT

The objective of this randomised open, active controlled, cross-over study was to evaluate the effect of a fixed combination of verapamil SR/trandolapril compared to captopril/hydrochlorothiazide on serum lipids, lipoproteins, and other metabolic and electrolyte parameters in patients with essential hypertension. Another objective was to assess the efficacy and safety of both combinations. One hundred hypertensives with systolic blood pressure 140-209 mm Hg and diastolic blood pressure 90-119 mm Hg were evaluated after 16 weeks receiving a fixed combination of verapamil SR 180 mg/ trandolapril 2 mg (VT) or captopril 50 mg/hydro- chlorothiazide 25 mg (CH) both given once daily. Lipids and lipoproteins were assessed in duplicate on 2 consecutive days. The study was completed by 80 patients. There was no statistically significant difference between the two combined regimens with respect to low-density lipoprotein (LDL)-cholesterol for the 'intention-to-treat' population measured at the end of each treatment period (3.44 +/- 0.87 mmol/L with VT, and 3.46 +/- 0.86 mmol/L with CH). No differences were found for other lipid parameters like total cholesterol, triglycerides, apolipoproteins A1 and B, Lp(a). High-density lipoprotein (HDL)-cholesterol was significantly higher with VT (1.39 +/- 0.01 vs 1.35 +/- 0.01, P < 0. 03). Serum potassium declined while uric acid and glucose increased on CH. In conclusion, no significant differences were found in LDL-cholesterol and in other lipid parameters with the exception of HDL-cholesterol which was significantly higher on VT. Serum potassium declined while uric acid and glucose increased on CH (all significantly). Both fixed combinations were well tolerated. The incidence of adverse events was higher on CH. Both fixed combinations significantly lowered BP. Journal of Human Hypertension (2000) 14, 347-354


Subject(s)
Captopril/administration & dosage , Electrolytes/metabolism , Hydrochlorothiazide/administration & dosage , Hypertension/drug therapy , Hypertension/metabolism , Indoles/administration & dosage , Verapamil/administration & dosage , Adolescent , Adult , Aged , Analysis of Variance , Angiotensin-Converting Enzyme Inhibitors/administration & dosage , Antihypertensive Agents/administration & dosage , Confidence Intervals , Cross-Over Studies , Delayed-Action Preparations/administration & dosage , Drug Combinations , Female , Humans , Hypertension/diagnosis , Lipoproteins/drug effects , Lipoproteins/metabolism , Male , Middle Aged , Treatment Outcome , Vasodilator Agents/administration & dosage
11.
Infect Immun ; 60(7): 3002-6, 1992 Jul.
Article in English | MEDLINE | ID: mdl-1612767

ABSTRACT

Clostridium novyi alpha-toxin caused retraction and rounding of cultured endothelial cells from porcine pulmonary arteries; nevertheless, the endothelial cells firmly adhered to their supports. F-actin stained with fluorescein-labeled phalloidin was condensed around the nucleus, whereas intermediate filaments and microtubules appeared unchanged. The content of F-actin and myosin was decreased, but that of G-actin or vimentin was not. A predominant role of the microfilament system in C. novyi alpha-toxin cytopathic action is suggested.


Subject(s)
Bacterial Toxins/pharmacology , Cytoskeleton/drug effects , Actins/analysis , Cells, Cultured , Clostridium/pathogenicity , Cytoskeleton/metabolism , Cytoskeleton/ultrastructure , Dose-Response Relationship, Drug , Microscopy, Electron
12.
Neurochem Int ; 17(2): 149-55, 1990.
Article in English | MEDLINE | ID: mdl-20504615

ABSTRACT

The effect of the sulfhydryl alkylating agent N-ethylmaleimide on the modulation of potassium-evoked [(3)H]noradrenaline release via inhibitory presynaptic receptors was studied using synaptosomes from rabbit hippocampus. Dose-response curves for the ?(2)-adrenoceptor agonist clonidine, the preferential ?-opioid receptor agonist ethylketocyclazocine and the A(1)-adenosine receptor agonist (?)phenylisopropyladenosine were compared to the effects of these agonists after pretreatment of [(3)H]noradrenaline loaded synaptosomes with N-ethylmaleimide (2 ?M) for 15 min. The inhibitory effects of all three agonists were attenuated to the same extent in a non-competitive manner after pretreatment with N-ethylmaleimide. Pertussis toxin-catalyzed [(32)P]ADP-ribosylation of synaptosomal proteins after purification of synaptosomes on a discontinuous Percoll gradient revealed the presence of three toxin-sensitive G proteins with apparent molecular weights of the ?-subunits between 41 and 39 kDa. N-Ethylmaleimide treatment of synaptosomes prior to pertussis toxin-catalyzed [(32)P]ADP-ribosylation reduced the incorporation of radioactivity into the toxin substrates to an extent comparable to the invalidation of agonist-induced inhibition of [(3)H]noradrenaline release. The quantitative agreement of the effects of N-ethylmaleimide on the modulation of [(3)H]noradrenaline release and on pertussis toxin-catalyzed [(32)P]ADP-ribosylation lends support to the proposal that inhibitory receptors on noradrenergic terminals in rabbit hippocampus are coupled to pertussis toxin-sensitive G proteins. The observation that the extent of functional antagonism after N-ethylmaleimide pretreatment was the same for all three agonists investigated is compatible with the existence of a common step in the signal transduction mechanism of the three pharmacologically different receptors, presumably on the level of a common G protein.

13.
Eur J Pharmacol ; 164(1): 45-53, 1989 May 02.
Article in English | MEDLINE | ID: mdl-2568939

ABSTRACT

A possible influence of botulinum A toxin on the modulation of evoked neurotransmitter release was investigated in hippocampus tissue. Rabbit hippocampal slices prelabelled with [3H]noradrenaline ([3H]NA), [3H]5-hydroxytryptamine ([3H]5-HT) or [3H]choline were superfused with physiological medium and were stimulated electrically during superfusion. The evoked release of [3H]NA, [3H]5-HT and [3H]acetylcholine [( 3H]ACh) was inhibited by botulinum A toxin in a concentration- and time-dependent manner. Neither the inhibition of release of [3H]NA and [3H]5-HT by the alpha 2-adrenoceptor agonist clonidine nor facilitation of release in the presence of alpha 2-antagonists were influenced by pretreatment of the tissue with botulinum toxin. The toxin caused no [32P]ADP ribosylation of synaptosomal proteins of hippocampus. The facilitation of the stimulation-induced [3H]NA and [3H]5-HT release by the specific protein kinase C (PKC) activator 4 beta-phorbol-12,13-dibutyrate (PDB) was significantly diminished by botulinum A toxin. These results show that the evoked transmitter release is inhibited by botulinum A toxin by a mechanism which does not involve ADP ribosylation or an interaction with the alpha 2-adrenoceptor mechanism.


Subject(s)
Botulinum Toxins/pharmacology , Neurotransmitter Agents/metabolism , Synapses/metabolism , Acetylcholine/metabolism , Adenosine Diphosphate/metabolism , Animals , Clonidine/pharmacology , Hippocampus/drug effects , Hippocampus/metabolism , In Vitro Techniques , Male , Norepinephrine/metabolism , Phorbol 12,13-Dibutyrate/pharmacology , Rabbits , Serotonin/metabolism , Synapses/drug effects , Yohimbine/pharmacology
14.
Arch Int Pharmacodyn Ther ; 296: 232-45, 1988.
Article in English | MEDLINE | ID: mdl-2907278

ABSTRACT

The effects of staurosporine, introduced as a very potent inhibitor of protein kinase C (PKC), on evoked neurotransmitter release were investigated and compared with those of the other PKC inhibitors: 1-(5-isoquinolinesulfonyl)-2-methylpiperazine (H7) and polymyxin B (PMB). Slices of rabbit hippocampus, prelabelled with either [3H]noradrenaline, [3H]5-hydroxytryptamine or [3H]choline were superfused with physiological medium. During superfusion the slices were stimulated either electrically (3 Hz, 5 V/cm, 24 mA, 2 msec) or by high K+ (30 mM) for 2 min, respectively. Both the electrically and potassium evoked overflow were increased by the PKC activator 4 beta-phorbol 12,13-dibutyrate (PDB). The degree of the enhancement by PDB was dependent on the transmitter and the stimulation conditions used. These results may be explained by differences in the extent of activation of PKC during electrically or potassium evoked release. The PDB-induced enhancement of electrically or potassium evoked release of the 3 transmitters was counteracted by staurosporine (1 microM) in concentrations much lower than those required for H7 (100 microM) and PMB (100 microM). PMB, which has been shown to decrease electrically evoked transmitter release, similarly diminished K+-evoked release. In contrast, only the potassium evoked [3H]acetylcholine release was significantly diminished by staurosporine (1 microM) and H7 (100 microM). In conclusion, these results show again that facilitation of neurotransmitter release by phorbol esters is due to activation of PKC.


Subject(s)
Alkaloids/pharmacology , Hippocampus/metabolism , Neurotransmitter Agents/metabolism , Phorbol Esters/antagonists & inhibitors , Protein Kinase C/antagonists & inhibitors , 1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine , Acetylcholine/pharmacology , Animals , Electric Stimulation , Hippocampus/drug effects , In Vitro Techniques , Isoquinolines/pharmacology , Norepinephrine/metabolism , Phorbol 12,13-Dibutyrate/pharmacology , Phorbol Esters/pharmacology , Piperazines/pharmacology , Polymyxin B/pharmacology , Potassium/pharmacology , Rabbits , Serotonin/metabolism , Staurosporine
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