Search PubMed⌕ Search

Biomedical subjects

G Corona

Publications and source records attributed to G Corona.

At least 37 records · Page 2Linked to original sources
PubMed1999

Pharmacokinetics of oral etoposide in patients with hepatocellular carcinoma.

Etoposide dosage in patients with liver dysfunction remains controversial. Since etoposide has a hepatic component to its clearance (CL) and shows a high degree of protein binding, hepatic impairment could affect etoposide disposition. However, the empiric recommendation that the dose of etoposide be decreased in such patients may reduce systemic exposure and be detrimental to its antitumor activity. To address these issues we studied the pharmacokinetics (PK) of etoposide in patients with hepatocellular carcinoma (HCC) and underlying cirrhosis (n = 17) treated with daily oral etoposide. Unbound etoposide was obtained by ultrafiltration. Etoposide concentrations (total and free drug) were measured by high-performance liquid chromatography (HPLC) and analyzed by noncompartmental equations. The patients had mild or moderate liver dysfunction. Albuminemia was in the normal range for all the patients. Creatininemia was normal in all but two patients. PK results (mean and range) showed that etoposide disposition was unchanged in patients with liver dysfunction. We found slightly high etoposide bioavailability [F, 61% (17-95%)] and clearance [CL, 1.1 (0.7-2.3)l h(-1) m(-2)] resulting in a normal degree of systemic exposure (AUC(oral) 27 microg h ml(-1)). Normal protein binding [PB 93.2% (84.4-98.1%)] contributed to a normal level of exposure to free drug (AUC(f, oral) 1.9 microg h ml(-1)). The distribution volume [V(SS) 8.4 (6.1-13.2) l/m2] and the effective half-life [t1/2eff, 5.1 (3.0-9.6) h] were normal. Median CL and protein binding did not differ in the seven patients with total bilirubin value of > 1.2 mg/dl as compared with the ten patients with total bilirubin levels of < or = 1.2 mg/dl (1.3 versus 1.01 h(-1) m(-2) and 92.5% versus 93.4%, respectively). In agreement with this PK finding, we observed no clinical evidence of increased toxicity in patients with hyperbilirubinemia as compared with patients with normal bilirubinemia (mean WBC decrease 38% versus 47%). The only case of severe (grade 4) hematological toxicity was observed in one patient with reduced glomerular filtration. Since the pharmacological effects of etoposide correlate with the level of systemic exposure to the free drug, our data suggest that no dose reduction is needed in patients with HCC. It is even possible to increase the dose intensity in patients with favorable PK parameters under appropriate hematological and therapeutic drug monitoring.

Administration, Oral↗
PubMed1999

Effect of cyclosporin A on protein binding of teniposide in cancer patients.

We investigated the effect of cyclosporin A (CSA) on protein binding of teniposide (VM26) in 16 patients with metastatic renal cell carcinoma receiving i.v. VM26 alone over 24 h (total dose, 200 mg/m2) and in association with CSA (5 mg/kg/2 h followed by 30 mg/kg/48 h i.v.). CSA was used in an attempt to overcome multidrug resistance. The unbound fraction (%fu) of VM26 was significantly (p=0.04) higher in the cycles with CSA (median 0.8; range 0.4-1.9) than in the cycles with VM26 alone (median 0.5; range 0.1-1.6). Both total VM26 area under curve concentration (AUC0-infinity) and free VM26 AUC0-infinity increased after treatment with CSA, but the median increase in free AUC0-infinity was higher (2.7-fold) than total AUC0-infinity (1.5-fold) (p = 0.04). Bilirubin was significantly (p<0.01) increased after CSA but no association was observed between bilirubin level and %fu of VM26. Albumin was in the normal range after both VM26 alone and VM26 plus CSA. The nadir of absolute neutrophil count (ANC) after VM26 plus CSA (median 700/microl, range <100-2860/microl) was lower than after VM26 alone (median 1900/microl, range 200-6000/microl) (p = 0.0007). The median percentage of ANC compared to the pretreatment value (ANC nadir/ANC pretreatment x 100) was 39.0% (range 3.1-98.8%) in the cycles with VM26 alone and 16.9% (range 1.4-97.9%) (p = 0.007) after VM26 plus CSA. Percentage change of neutrophils significantly correlated with free AUC0-infinity VM26 in the cycles with VM26 alone and VM26 plus CSA (p = 0.04, r = -0.53 and p = 0.04, r = -0.52, respectively). Only a trend which failed to reach significance was observed between total AUC0-infinity VM26 and percentage change of neutrophils in the cycles with VM26 alone and in association with CSA (p = NS, r = -0.33 and p = 0.055, r = -0.49, respectively). In conclusion, patients treated with CSA had higher systemic exposure to unbound VM26.

Adult↗
PubMed1999

Pharmacokinetic interaction between etoposide and tamoxifen in patients with hepatocellular carcinoma.

The effect of tamoxifen (TAM) on the pharmacokinetics of oral administration of etoposide (VP-16) in patients with nonoperable hepatocellular carcinoma was investigated. The pharmacokinetics of VP-16 was studied by using a validated limited sampling strategy. The pharmacokinetic parameters of VP-16, such as area under curve (AUC), free AUC and protein binding, were determined from drug plasma concentrations at 1 and 4 h after VP-16 administration on the first day (day -1) and at the end of the chemotherapy cycle (day -21) for VP-16 alone and VP-16+TAM, respectively. When VP-16 was administered in association with TAM, the median total systemic exposure was not significantly (p = NS) different from that observed when VP-16 was administered alone [33.74 (range 11.19-56.58) versus 32.97 (range 20.23-119.28) mg/l/h]. Moreover, TAM did not affect significantly (p = NS) the levels of protein binding of VP-16 [median 94.6 (range 87.7-98.2) versus median 94.9 (range 91.6-98.0)% for VP-16+TAM and VP-16 alone, respectively] and the systemic exposure of the free drug (free AUC) [1.86 (range 0.21-4.57) versus median 1.78 (range 0.59-3.73) mg/l/h for VP-16+TAM and VP = 16 alone, respectively]. These results indicate a lack of pharmacokinetic interaction between VP-16 and TAM, and suggest that the increased hematological toxicity observed when TAM is given in combination with VP-16 could be related to pharmacodynamic interactions.

Aged↗
PubMed1998

Role of folate receptor and reduced folate carrier in the transport of 5-methyltetrahydrofolic acid in human ovarian carcinoma cells.

Folate receptor-alpha (FR-alpha) is generally over-expressed in non-mucinous human ovarian carcinomas. The meaning of FR-alpha over-expression and its role in the 5-methyltetrahydrofolic acid (N5-CH3-H4PteGlu) transport in such tumors is not clear, especially compared with the reduced folate carrier (RFC), the other known folate transporter. In this study, we analyzed molecular FR-alpha and RFC expression in 16 ovarian carcinoma tissues and in 5 ovarian carcinoma cell lines using competitive PCR. Co-expression of the 2 transporters was found both in vivo and in vitro. FR-alpha mRNA expression in the cell lines was in good agreement with the corresponding protein expression evaluated by cellular folic acid binding and immunofluorescence analysis, using a specific monoclonal antibody (MAb) (MOv18). Moreover, RFC mRNA expression levels were consistent with the selective cellular binding of N-hydroxysuccinimide of [3H]-methotrexate (NHS-MTX). The 5 ovarian carcinoma cell lines (IGROV-1, SW-626, SKOV-3, OVCAR-3 and OAW-42), grown at physiological N5-CH3-H4PteGlu concentrations (20 nM) and expressing FR-alpha and RFC levels superimposable to those observed in vivo, were used as in vitro cellular model to evaluate the different contribution of FR-alpha and RFC to the transport of N5-CH3-H4PteGlu. The cytoplasmic N5-CH3-[3H]H4PteGlu accumulation observed in each cell line was approximately linear over 4 hr of incubation, but there was no correlation between the rate of folate internalization and FR-alpha and RFC expression levels. Furthermore, the selective inhibition of FR-alpha and RFC functionality allowed us to distinguish their differential role on the overall N5-CH3-[3H]H4PteGlu intracellular delivery. Treatment with the N-hydroxysuccinimide of folic acid, which blocks FR-alpha activity, showed only a partial inhibition (about 20%) of folate internalization in all the cell lines. In contrast, the inhibition of RFC by NHS-MTX, under conditions that did not affect FR-alpha functionality, generally reduced folate accumulation by more than 70%. Only one cell line (IGROV-1) showed a comparable contribution of the 2 transport systems. Our findings suggest that in ovarian carcinomas, in spite of its over-expression, FR-alpha generally plays a minor role in N5-CH3-H4PteGlu transport compared with RFC.

Biological Transport↗
PubMed1997

Reversal activity of cyclosporin A and its metabolites M1, M17 and M21 in multidrug-resistant cells.

Cyclosporin A (CSA) is an effective inhibitor of the P-glycoprotein (P-gp) activity and has been shown to modulate multidrug resistance (MDR) in in vitro experimental models. During degradation of CSA, the metabolites arising from the parental compound reach high levels in the serum of patients, and it is not clear whether these metabolites maintain the reversal activity of the parental compound, like the metabolites of verapamil. In an in vitro experimental model, we compared the reversal activity of CSA and 3 CSA metabolites (M1, M17, and M21) in the range of concentrations obtained in whole blood during a clinical trial with CSA used as a revertant agent. As experimental model we used LoVo-resistant cells. Our in vitro studies indicated that the metabolic hydroxylation and demethylation of CSA lead to molecules that greatly differ from the parent drug in their reversal activity. In the range of concentration detected in the whole blood of the patients (1-3 microM), CSA had a significant reversal activity. It decreased the IC50 of antineoplastic drugs involved in MDR (vincristine, taxol, doxorubicin and etoposide) but not the IC50 of platinum or methotrexate. CSA increased intracellular doxorubicin content and inhibited P-gp 3[H]azidopine photolabeling. Conversely, CSA metabolite concentrations superimposable to those observed in the patients (0.5-2.2 microM) had no sensitizing effects on the cytotoxicity of MDR-related anti-neoplastic drugs, nor did they affect 3[H]azidopine photolabeling or doxorubicin uptake. This study demonstrates that, during degradation of CSA, metabolite derivatives arise that have a very different reversal activity from that of the parental compound.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1997

Homocysteine accumulation in human ovarian carcinoma ascitic/cystic fluids possibly caused by metabolic alteration of the methionine cycle in ovarian carcinoma cells.

The major role of the high-affinity folate-binding protein (FBP) is to regulate cellular folate homeostasis by increasing folate uptake in case of extracellular and intracellular folate deficiency. On this basis, we hypothesised that the overexpression of FBP in ovarian carcinoma might be physiologically associated with folate deficiency in the extracellular fluids, where ovarian carcinoma cells develop in vivo, or it might be the result of a reduced intracellular regeneration of the 5-methyltetrahydrofolate (5-CH3H4 folate). To test these hypotheses, we determined the bioavailability of folate in serum and in ascitic/cystic fluids of ovarian carcinoma patients (n = 36). The intracellular shortage of 5-CH3H4 folate was evaluated in the extracellular fluids by measuring the concentration of homocysteine (Hcy), which is a useful marker of intracellular folate deficiency. Patients with ascites from malignant and benign non-ovarian pathologies were used as controls (n = 30). We found no folate shortage in the serum and ascitic/cystic fluids of ovarian carcinoma patients. The folate concentration was within the normal range and superimposable on that observed in serum and ascites of control patients. However, the ascitic/cystic Hcy concentration was significantly higher (P < 0.005) than the corresponding serum concentration in a large fraction of ovarian carcinoma patients (72%, 26/36), whereas it was higher only in a small fraction of patients with non-ovarian malignant ascites (24%, 4/17), and in no patient with benign ascites. Hcy accumulation in ovarian carcinoma patients was not associated with a defect in the catabolic pathway of Hcy to cysteine, but was consistent with an impaired remethylation process of Hcy to methionine caused by an intracellular shortage of 5-CH3H4 folate. This suggests a possible association between FBP overexpression and a biochemical defect of the cellular folate metabolism involved in the methionine cycle.

Adult↗
PubMed1997

Cyclosporin A as a multidrug-resistant modulator in patients with renal cell carcinoma treated with teniposide.

Patients with refractory metastatic renal cell carcinoma (RCC) were enrolled in a phase II study with teniposide (VM26) and cyclosporin A (CSA) to investigate (1) the effect of CSA on the response rate to VM26; and (2) the effect of CSA on the pharmacokinetics and pharmacodynamics of VM26. Sixteen patients initially received VM26 alone (200 mg m(-2) day(-1) i.v.). No objective responses were observed and all patients crossed over to receive at least an additional two courses (range 2-5) of VM26 plus CSA (5 mg kg(-1) 2h(-1) followed by 30 mg kg(-1) 48h(-1) i.v.). At the end of the 2-h loading dose of CSA, whole-blood CSA levels ranged from 2250 to 3830 ng ml(-1), whereas at the end of the 48-h CSA infusion, CSA ranged from 1830 to 4501 ng ml(-1). CSA significantly (P<0.01) increased the area under the curve (AUC) of VM26. The variation in the paired AUC of VM26 was 50%. Terminal half-life of VM26 was significantly (P<0.01) increased (1.72-fold) after CSA administration, whereas the systemic clearance of VM26 was decreased by 1.4-fold (P<0.01). The nadir neutrophil count after VM26 plus CSA (median 700 microl(-1), range <100 to 2860 microl(-1)) was lower than after VM26 alone (median 1900 microl(-1), range 200 to 6000 microl(-1)). Increased haematological toxicity after CSA could be explained by the increase in the VM26 AUC and by inhibition of P-glycoprotein (P-gp) activity in haematopoietic precursor cells. Bilirubin concentrations in the serum were increased after VM26 plus CSA compared with VM26 alone (P<0.01). Among the 15 patients evaluable for response, one had a minor response, eight had stable disease, and six had progressive disease. In conclusion, the dose of CSA we used achieved plasma concentrations within the effective range for P-gp inhibition. CSA affected both the pharmacokinetics and pharmacodynamics of VM26 in the patients, principally by increasing the plasma concentrations of the antineoplastic drug and VM26 haemopoietic toxicity.

Adult↗
PubMed1997

Bioavailability of two different oral formulations of amoxicillin in healthy subjects.

A study was carried out in 12 healthy volunteers to assess the bioavailability of two different oral formulations of amoxicillin (CAS 26787-78-0). A single 1000 mg oral dose of drug was given according to a randomized two-way crossover design as tablet (treatment A) and capsule (treatment B, Gramidil) and blood samples were drawn at selected times during 24 h. A 7-day wash-out period separated each dose. Amoxicillin plasma concentrations were determined by HPLC, and the stability of drug was studied to verify the possibility of an automated batch processing overnight. Amoxicillin was rapidly absorbed after administration of either formulation and individual plasma concentration-time profiles were constructed. Cmax and AUC values were compare by analysis of variance (ANOVA) followed by Westlake's confidence interval test. 95% confidence limits ranged from 80 to 125% for Cmax and AUC. With respect to tmax, Friedman test was used to compare formulations. It is concluded that the two assayed amoxicillin formulations may be considered to have the same bioavailability.

Adolescent↗
PubMed1996

Cellular pharmacology of idarubicinol in multidrug-resistant LoVo cell lines.

Idarubicin (IDA) is a daunorubicin (DAU) analog that is being used to treat a variety of human malignancies. The major circulating metabolite of IDA is idarubicinol (IDOL). After administration of IDA to patients, the systemic exposure to IDOL is greater than IDA. We investigated the cytotoxic effect of IDOL in the LoVo human colon-carcinoma cell line and its derivative multidrug-resistant (MDR) sub-lines. In LoVo-sensitive cells, the extracellular IDOL concentration inhibiting cell growth by 50% (IC50) was about 2-fold higher than IDA IC50 but lower than DAU IC50. After continuous exposure of the LoVo parental cells to 20 nM IDOL, 5 drug-resistant clones were obtained. All these clones exhibited an MDR phenotype, indicating that IDOL is involved in multidrug resistance. The resistance index (RI) to IDOL was investigated in LoVo MDR sub-lines obtained by IDOL (LoVo-IDOL-1), IDA (LoVo-IDA-1) and DOX (LoVo-DOX-1) selection. In spite of the drug used for their selection, all the MDR sub-lines exhibited an RI to IDOL lower than DAU and only 2-fold higher than IDA. In LoVo-IDOL-1 cells the RI was 5, 11 and 32 for IDA, IDOL and DAU respectively. Differences in the RI were explained by the greater intracellular tolerance exhibited by MDR cells to DAU than to IDOL and IDA. In the LoVo-IDOL-1 sub-line, the intracellular drug concentration inhibiting cell growth by 50% (IC50int) was higher than in the sensitive cells by 11.4-, 4.7- and 2.8-fold for DAU, IDOL, and IDA respectively. Differences in the intracellular tolerance were explained by the different intracellular distribution of DAU compared with IDOL and IDA. While DAU had a higher nuclear location in LoVo-sensitive cells than in resistant cells, IDOL and IDA maintained the same distribution both in sensitive and in resistant cells. In conclusion, contrary to what has been observed for other derivative metabolites of anthracyclines, the metabolism of IDA to IDOL must not be considered an inactivation pathway. IDOL is a potent inhibitor of cell growth and retains good activity in MDR cells.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1996

Inhibition of Pgp activity and cell cycle-dependent chemosensitivity to doxorubicin in the multidrug-resistant LoVo human colon cancer cell line.

To determine whether the cell cycle affects multidrug resistance (MDR) and its reversal, doxorubicin (DOX) cytotoxicity and the effect of inhibition of P-glycoprotein (Pgp) activity by verapamil (VER) were investigated in MDR LoVo cell lines (LoVo-R) in different phases of the cell cycle. Synchronised cells were obtained by exposing cells for 24 h to non-toxic concentrations (40 nmol/l) of methotrexate (MTX), which induced a reversible blockade in the S phase. DOX cytotoxicity was higher if cells were exposed to DOX shortly after the pretreatment with MTX, when most cells were in the S phase of the cell cycle. At that time, the DOX concentration inhibiting cell growth by 50% (IC10) was decreased by approximately 4-fold compared to non-synchronised cycling cells. DOX cytotoxicity remained high during the transition from the S to the G2M phase, but was reduced when the cells had shifted to the G2M phase. Inhibition of Pgp activity by VER (6 mumol/l) enhanced DOX uptake and resulted in an intracellular nuclear compartmentalisation of DOX in LoVo-R cells. These effects were not significantly different (P = NS) in the different phases of the cell cycle. However, similar increases in intracellular DOX uptake due to the inhibitory effect of VER on Pgp greatly potentiated DOX cytotoxicity in LoVo-R cells synchronised in the S or G2M phase compared with non-synchronised cycling cells. The ratio between DOX IC50 in the absence and presence of VER in LoVo-R cells synchronised in the S phase and in cycling cells was 11.1 and 4.1, respectively (P < 0.01). This greater potentiation could be explained by the increased chemosensitivity of the S- and G2M-phase cells to intracellular DOX concentration compared with the non-synchronised cells. Finally, the combination of synchronisation by MTX and of inhibition of Pgp activity by VER produced a considerable reduction in DOX IC50 (approximately 50-fold) in LoVo-R cells compared with the cells not treated with MTX and VER. In conclusion, this study demonstrates that, in LoVo-R cells, the effect of Pgp inhibition on DOX cytotoxicity is dependent on cell cycle phase. DOX cytotoxicity is maximal when inhibition of Pgp activity occurs during the S/G2M phases.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1995

Structure-activity relationship of verapamil analogs and reversal of multidrug resistance.

We studied the relationship between the chemical structure and multidrug resistance (MDR) reversal activity of racemic verapamil (VER) and 14 VER analogs (VAs). The LoVo-R human colon carcinoma cell line was used as an experimental model. This cell line exhibited a typical MDR phenotype and overexpressed the MDR1 gene products. Key structural features were identified as being related to MDR reversal and cytotoxic activity. In particular, we demonstrated that the methoxy groups in the VER molecule structure [1.7-Bis-(3.4-dimethoxyphenyl)-3-methylaza-7-cyan-8-methyl-n onane] prevented cytotoxicity when the VAs were used alone, whereas the 7-cyan-8-methyl groups were important for MDR reversal activity and interaction with P-glycoprotein (P-gp). Among the VAs tested, the most active compounds were gallopamil, R-isomer of VER (R-VER), and nor-VER, which potentiated doxorubicin (DOX) cytotoxicity by 52.3 +/- 7.2 (n = 3 +/- SD), 38.9 +/- 6.4 (n = 4 +/- SD), and 35.4 +/- 4.3 (n = 3 +/- SD) times, respectively. The reversal activity of these compounds was similar to that of VER, which enhanced DOX cytotoxicity by 41.3 +/- 5.0 (n = 3 +/- SD) times. The potentiation of DOX cytotoxicity was associated with an increase in DOX uptake in LoVo-R cells and with an increased [3H]azidopine P-gp photolabeling inhibition. Some compounds that had a high reversal potency (i.e. R-VER and nor-VER) showed a lower calcium antagonist activity than VER, and seem useful candidates for the treatment of MDR in cancer patients.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1994

Structure-function studies of human ciliary neurotrophic factor.

Ciliary neurotrophic factor (CNTF) is a polypeptide that promotes the survival and/or differentiation of a number of neural cell types. Here we present a structural and functional analysis of the human CNTF molecule. Variant proteins were synthesized by Escherichia coli transformed with mutant cDNA constructs, and purified by SDS-polyacrylamide gel electrophoresis and reverse phase high pressure liquid chromatography. Most variant CNTF proteins lacked neurotrophic activity, but two N- and C-terminal deletions (delta 2-14 and delta 173-200, respectively) actually displayed a several-fold increase in specific activity. Loss of biological activity was accompanied by changes in the alpha-helical nature of CNTF as measured by circular dichroism. These data strengthen the proposed similarity between CNTF and the family of hematopoietic cytokines.

Animals↗
PubMed1993

Production and characterization of monoclonal antibodies to human ciliary neurotrophic factor with defined epitope recognition.

Ten mouse hybridoma lines producing monoclonal antibodies (Mabs) against recombinant human ciliary neurotrophic factor (rhCNTF) have been obtained. Two monoclonal antibodies belonging to the IgG1 class were selected and characterized. Their specificity was established by ELISA and Western blotting. Epitopes recognized by the two Mabs were investigated with ELISA and Western blotting by using rhCNTF mutants, rhCNTF fragments and synthetic peptides mimicking different portions of the CNTF molecule. The carboxy-terminal part of the CNTF and particularly the sequence between aa 150 and 159 appeared to constitute the immunodominant group. The fact that certain amino acid sequences of CNTF are conserved among species was utilized to examine the crossreactivity patterns of the two Mabs with rat sciatic nerve CNTF by Western blotting and immunohistochemistry. These antibodies will be useful for studying the distribution of CNTF in the nervous system and in developing an enzyme-linked immunosorbent assay for the quantitative determinations of CNTF in various neuropathologies.

Amino Acid Sequence↗
PubMed1992

Neutralization of the antiheparin activity of platelet factor 4 by a monoclonal antibody.

We have produced a panel of monoclonal antibodies (mAbs) against rabbit platelet factor 4 (PF4). Two of these mAbs have been characterized in this study. In particular the antibody called 10B2, which also recognizes the human molecule, is able to block PF4's ability to neutralize heparin in a modified Heparin-Factor Xa chromogenic assay. The inhibition appears to be more than 95% at 1:1 mAb/PF4 molar ratio both for purified rabbit and human PF4. Similar results were obtained using supernatants from stimulated human platelets (90% of inhibition at 1:1 mAb/PF4 molar ratio) or using Fab fragments from 10B2. Studies to determine the antigenic determinant against which 10B2 is directed, show that this is an assembled epitope which involves disulfide bonds of the PF4.

Amino Acid Sequence↗
PubMed1991

Synthesis, purification, and characterization of human ciliary neuronotrophic factor from E. coli.

The cDNA for human ciliary neuronotrophic factor (CNTF) has been cloned into an expression vector under the control of the T7 promoter. The BL21 strain of E. coli was transformed with this vector. Human CNTF accounted for about 30% of the total bacterial protein after induction with isopropyl-B-D-thiogalactopyranoside. This human CNTF was purified to homogeneity from inclusion bodies by a combination of ion exchange chromatography and reverse-phase high performance liquid chromatography. The amino-terminal amino acid sequence of the purified protein was identical to the deduced amino acid sequence; however, the methionyl residue has been removed. On SDS-PAGE gels, human CNTF displayed a molecular weight of about 24 kDa, in accord with its deduced molecular mass; a pI of 5.8 indicates the acidic nature of the molecule. A proposed structure for human CNTF includes major alpha helical regions. The ED50 of purified human CNTF was approximately 30 pM, using cultured embryonic day 10 chicken dorsal root ganglion neurons; no activity was observed with neurons from embryonic day 8 ganglia. Polyclonal antibodies prepared against both a synthetic peptide of CNTF and the entire human CNTF protein recognized a single 24 kDa band on Western blots, corresponding to human CNTF. However, only the antibodies against intact CNTF blocked its biological activity. This represents the first molecular expression and purification of human CNTF.

Base Sequence↗
PubMed1991

A simple method to detect contaminating peptides and amino acids in large-scale ganglioside preparations.

A reverse-phase liquid chromatography method was developed to analyse the presence of contaminating peptides and amino acids in large-scale monosialoganglioside preparations. Samples were hydrolysed under controlled conditions and derivatized with phenylisothiocyanate. PTC-amino acids were then separated and identified by HPLC. The sensitivity of the method allowed detection of a least 50 pmoles of amino acid per mg of ganglioside with excellent reproducibility and little or no interference of by-products derived from hydrolysis of the glycosphingolipid. The response was consistently linear for each amino acid within the examined analytical range. The ease and speed of performance make this method a useful tool for rapidly monitoring large-scale extraction and purification processes of biologicals obtained from natural sources.

Amino Acid Sequence↗
PubMed1989

[Ultrasonic study of the pelvis in patients with Cooley's anemia].

Nowadays the role of sonography (US) as a method of first choice in female pelvic pathology, is well determined. The authors used sonography in 23 patients aged between 13 and 36 years, affected by thalassemia major, in order to determine biometric and structural data of both uterus and ovaries. Morphological and clinical-laboratory studies have been performed in order to have a complete vision about the delay in ovarian maturation, commonly seen in these patients. Many cases of hypoplastic uterus and micropolycystic ovaries have been found. US, simple and widely diffused method, allow the evaluation of uterine and ovarian pathologic conditions and the relationship with ovarian maturation delay, and their follow-up. In some cases US may have a value in previewing menarche, in association with clinical-laboratory data.

Adolescent↗