Hb-M "Hyde Park": a de novo mutation, identified by mass spectrometry and DNA analysis.

BACKGROUND. Structural hemoglobinopathies usually are inherited as autosomic dominant traits; de novo mutations are uncommon. Analytical and preparative procedures for the characterization of an abnormal hemoglobin are complex and time-consuming. Mass spectrometer analysis allows a rapid identification of the amino acid substitution. METHODS AND RESULTS. A cyanotic 7-year-old girl was found to have 16% methemoglobin. Laboratory data showed the presence of an abnormal hemoglobin, which was isolated by collecting the abnormal peak from DEAE and globin chains from CM52. The amino acid substitution was rapidly identified by FAB mass spectroscopic analysis, leading to the recognition of HbM Hyde Park. These data were confirmed by molecular analysis (Southern blot and DNA sequencing). Neither the parents nor a sister showed any abnormality; non-paternity was excluded by blood group serology and HLA typing. CONCLUSIONS. This is a case of HbM Hyde-Park arising as a de novo mutation. FAB mass spectroscopic analysis is a rapid and useful analytical method for identifying aminoacid substitution.     

Heparin-interacting sites of bovine lactoferrin are involved in anti-adenovirus activity

Lactoferrin, a member of the transferrin family of approximately 80 kDa, consists of a single polypeptide chain folded in two symmetric, globular lobes (N- and C-lobes), each able to bind one ferric ion. This glycoprotein, found in physiological fluids of mammals, plays an important role in immune regulation and in defense mechanisms against bacteria, fungi, parasites, and viruses. Although the antiviral activity of lactoferrin is one of the major biological functions of such protein, the mechanism of action is still under debate. We have investigated both the role of tryptic fragments of bovine lactoferrin and the mechanism of lactoferrin antiviral effect toward adenovirus infection in HEp-2 cells. The results obtained demonstrated that the anti-adenovirus activity of lactoferrin is mediated by the N-terminal half of the protein as the N-lobe was able to inhibit adenovirus infection, even if at lower extent than undigested lactoferrin, whereas C-lobe was ineffective. The results also showed that the anti-adenovirus action of lactoferrin and of its N-terminal peptide lactoferricin took place on virus attachment to cell membrane, mainly through competition for common glycosaminoglycan receptors. The data provide evidence that the anti-adenovirus activity of lactoferrin is mediated mainly by the cluster of positive charges at the N-terminus of whole molecule and that the N-terminal peptide lactoferricin alone is sufficient to prevent infection.     

Is there a case for cisplatin in the treatment of small-cell lung cancer? A meta-analysis of randomized trials of a cisplatin-containing regimen versus a regimen without this alkylating agent

Chemotherapy is the backbone of small-cell lung cancer therapy. However, optimal drug combinations and schedules remain to be defined and there is hitherto no world-wide accepted standard regimen. Cisplatin, an alkylating agent with high putative toxicity is currently widely used although its effectiveness in this disease has not been established firmly. We conducted a meta-analysis of published data reporting trials randomizing a cisplatin-containing regimen versus a regimen without this alkylating agent in order to determine possible differences in survival response and toxicity. Nineteen trials have been identified in medical literature (4054 evaluable patients). Ten trials randomized patients to receive a cisplatin-etoposide regimen versus a regimen without any of these two drugs. A subgroup analysis was, therefore, carried out in the nine remaining trials that randomly allocated patients between two regimens differing in the absence or presence of cisplatin, whereas etoposide was given (or not given) in both arms (1579 evaluable patients). The DerSimonian and Laird method was used to estimate the size effects and the Peto and Yusuf method was used in order to generate the odds ratios (OR) of reduction in risk of death and the increase in probability of being responders to chemotherapy. There was no significant difference between the cisplatin-containing regimen and the regimen without this drug when the risk of toxic-death was taken into account with respective probabilities of 3.1 and 2.7% (NS). Patients randomized in a cisplatin-containing regimen had an increase in probability of being responders with an OR of 1.35, 95% confidence interval (CI) of 1.18-1.55; P < 10(-5) corresponding to an increase of objective (partial plus complete) response rate from 0.62 to 0.69 (a result taking into account a significant heterogeneity). Patients treated with a cisplatin-containing regimen benefited from a significant reduction of risk of death at 6 months and 1 year with respective OR 0.87, 95% CI 0.75-0.98, P = 0.03, and or 0.80, 95% CI 0.69-0.93, P = 0.002 (no statistical heterogeneity). This corresponded to a significant increase in the probability of survival of 2.6% and 4.4% at 6 months and 1 year respectively. The meta-analysis restricted to the subset of nine trials without etoposide treatment imbalance reached similar conclusions. A cisplatin-containing regimen yields a higher response rate and probability of survival than does a chemotherapy containing others alkylating agents without a perceptible increase in risk of toxic-death.     

Sequence variations of the alpha-globin genes: scanning of high CG content genes with DHPLC and DG-DGGE

The alpha-globin chains are encoded by two duplicated genes (HBA2 and HBA1, 5'-3') showing overall sequence homology >96% and average CG content >60%. alpha-Thalassemia, the most prevalent worldwide autosomal recessive disorder, is a hereditary anemia caused by sequence variations of these genes in about 25% of carriers. We evaluated the overall sensitivity and suitability of DHPLC and DG-DGGE in scanning both the alpha-globin genes by carrying out a retrospective analysis of 19 variant alleles in 29 genotypes. The HBA2 alleles c.1A>G, c.79G>A, and c.281T>G, and the HBA1 allele c.475C>A were new. Three pathogenic sequence variations were associated in cis with nonpathogenic variations in all families studied; they were the HBA2 variation c.2T>C associated with c.-24C>G, and the HBA2 variations c.391G>C and c.427T>C, both associated with c.565G>A. We set up original experimental conditions for DHPLC and DG-DGGE and analyzed 10 normal subjects, 46 heterozygotes, seven homozygotes, seven compound heterozygotes, and six compound heterozygotes for a hybrid gene. Both the methodologies gave reproducible results and no false-positive was detected. DHPLC showed 100% sensitivity and DG-DGGE nearly 90%. About 100% of the sequence from the cap site to the polyA addition site could be scanned by DHPLC, about 87% by DG-DGGE. It is noteworthy that the three most common pathogenic sequence variations (HBA2 alleles c.2T>C, c.95+2_95+6del, and c.523A>G) were unambiguously detected by both the methodologies. Genotype diagnosis must be confirmed with PCR sequencing of single amplicons or with an allele-specific method. This study can be helpful for scanning genes with high CG content and offers a model suitable for duplicated genes with high homology.     

An antibody‐free strategy for screening putative HDM2 inhibitors using crude bacterial lysates expressing GST‐HDM2 recombinant protein

Targeting the interaction of p53 with its natural inhibitor MDM2 by the use of small synthetic molecules has emerged as a promising pharmacological approach to restore p53 oncosuppressor function in cancers retaining wild‐type p53. The first critical step in the experimental validation of newly synthesized small molecules developed to inhibit MDM2‐p53 interaction is represented by the evaluation of their efficacy in preventing the formation of the MDM2‐p53 complex. This can be achieved using the in vitro reconstructed recombinant MDM2‐p53 complex in cell‐free assays. A number of possible approaches have been proposed, which are however not suitable for screening large chemical libraries, due to the high costs of reagents and instrumentations, or the need of large amounts of highly pure recombinant proteins. Here we describe a rapid and cheap method for high‐throughput screening of putative inhibitors of MDM2‐p53 complex formation – based on the use of GST‐recombinant proteins – that does not require antibodies and recombinant protein purification steps from bacterial cell lysates. Copyright © 2013 John Wiley & Sons, Ltd.