Stagnation of histopathological improvement is a predictor of hepatocellular carcinoma development after hepatitis C virus eradication

BACKGROUND

Hepatocellular carcinoma (HCC) develops in some patients who achieve sustained virological response (SVR) against hepatitis C virus (HCV) infection via anti-HCV therapy. To examine the pathogenesis of HCC development after HCV eradication, histopathological changes and clinical markers were evaluated in SVR patients.

METHODS

Of 654 SVR patients treated with interferon (IFN)-based therapies, 34 patients who had undergone liver biopsy before initiating IFN therapy and after SVR achievement were enrolled: 11 patients with HCC and 23 patients without HCC (male/female, 9/2 and 8/15, respectively: age, 58 ± 5 and 54 ± 11 years, respectively). We compared the clinical and histopathological factors between the two groups. Immunohistochemistry for Cytoglobin (CYGB) and α smooth muscle actin (α-SMA) was also performed.

RESULTS

At baseline, prior to initiating the IFN-based therapy, there were significant differences between the SVR-non-HCC and SVR-HCC groups in the male gender, HBc antibody positivity, prothrombin activity, and histological inflammatory grade. Histopathological evaluation, using the new Inuyama classification system, revealed an improvement in the inflammatory grade, from 2.1 ± 0.6 to 1.0 ± 0.6 (p < 0.0001), whereas the fibrosis stage remained unchanged, from 2.3 ± 0.9 to 2.0 ± 1.2 (p = 0.2749), during the 97 ± 72-month observation period in the SVR-HCC group. Both the grade and stage scores were significantly improved in the SVR-non-HCC group. The area of collagen deposition, evaluated using Sirius red staining, showed a marked decrease, from 18.6 ± 7.6% to 7.7 ± 4.6%, in the SVR-non-HCC group, with no change in the SVR-HCC group. CYGB- and α-SMA-positive hepatic stellate cells (HSCs), indicative of the HSC activated phenotype, remained in the fibrotic tissue of livers among patients in the SVR-HCC group.

CONCLUSION

Stagnation of fibrosis regression is associated with a high risk for HCC after SVR. HSC activation may inhibit improvement in fibrosis after SVR and potentially contribute to hepatocarcinogenesis.

ERβ-dependent neuroglobin up-regulation impairs 17β-estradiol-induced apoptosis in DLD-1 colon cancer cells upon oxidative stress injury

Besides other mechanism(s) 17β-estradiol (E2) facilitates neuronal survival by increasing, via estrogen receptor β (ERβ), the levels of neuroglobin (NGB) an anti-apoptotic protein. In contrast, E2 could exert protective effects in cancer cells by activating apoptosis when the ERβ level prevails on that of ERα as in colon cancer cell lines. These apparently contrasting results raise the possibility that E2-induced NGB up-regulation could regulate the ERβ activities shunning this receptor subtype to trigger an apoptotic cascade in neurons but not in non-neuronal cells. Here, human colorectal adenocarcinoma cell line (DLD-1) that only expresses ERβ and HeLa cells transiently transfected with ERβ encoding vector has been used to verify this hypothesis. In addition, neuroblastoma SK-N-BE cells were used as positive control. Surprisingly, E2 also induced NGB up-regulation, in a dose- and time-dependent manner, in DLD-1 cells. The ERβ-mediated activation of p38/MAPK was necessary for this E2 effect. E2 induced NGB re-allocation in mitochondria where, subsequently to an oxidative stress injury (i.e., 100μM H2O2), NGB interacted with cytochrome c preventing its release into the cytosol and the activation of an apoptotic cascade. As a whole, these results demonstrate that E2-induced NGB up-regulation could act as an oxidative stress sensor, which does not oppose to the pro-apoptotic E2 effect in ERβ-containing colon cancer cells unless a rise of oxidative stress occurs. These results support the concept that oxidative stress plays a critical role in E2-induced carcinogenesis and further open an important scenario to develop novel therapeutic strategies that target NGB against E2-related cancers.

Heat-passing framework for robust interpretation of data in networks

Researchers are regularly interested in interpreting the multipartite structure of data entities according to their functional relationships. Data is often heterogeneous with intricately hidden inner structure. With limited prior knowledge, researchers are likely to confront the problem of transforming this data into knowledge. We develop a new framework, called heat-passing, which exploits intrinsic similarity relationships within noisy and incomplete raw data, and constructs a meaningful map of the data. The proposed framework is able to rank, cluster, and visualize the data all at once. The novelty of this framework is derived from an analogy between the process of data interpretation and that of heat transfer, in which all data points contribute simultaneously and globally to reveal intrinsic similarities between regions of data, meaningful coordinates for embedding the data, and exemplar data points that lie at optimal positions for heat transfer. We demonstrate the effectiveness of the heat-passing framework for robustly partitioning the complex networks, analyzing the globin family of proteins and determining conformational states of macromolecules in the presence of high levels of noise. The results indicate that the methodology is able to reveal functionally consistent relationships in a robust fashion with no reference to prior knowledge. The heat-passing framework is very general and has the potential for applications to a broad range of research fields, for example, biological networks, social networks and semantic analysis of documents.

Resonance micro-Raman investigations of the rat medial preoptic nucleus: effects of a low-iron diet on the neuroglobin content

The aim of this study was to investigate the medial preoptic nucleus (MPN) of the anterior hypothalamus by resonance Raman spectroscopy (514.5 nm) to determine if it is possible to enhance the Raman scattering of hemoproteins in fresh brain tissue slices. The resonance effect was compared with near-infrared Raman spectra. Two groups of male Sprague Dawley rats were studied, one control group on a normal diet and one group on a low-iron diet to evoke iron deficiency. Each group consisted of four rats, 38-41 days old. The diets lasted for 11, 12, and 15 days. The MPN regions of brain tissue slices were analyzed by monitoring raw and pre-processed mean data, by cluster analysis, and by deriving difference spectra from pre-processed mean spectra. Cluster analysis of the resonance Raman spectra could identify different hemoprotein groups, namely, hemoglobin (Hb) and neuroglobin (Ngb). Spectra from randomly distributed spots revealed high Hb content, whereas Ngb was evenly distributed in the MPN. The different spectra showed a decrease of the Ngb and lipid content for the animals on the low-iron diet. The Ngb decrease was approximately 20%. The data show that resonance Raman spectroscopy is well suited to study hemoproteins in fresh brain tissue.

[Changes of neuroglobin in the pathologic process of contusion and laceration of brain in children]

OBJECTIVE

To study the role of neuroglobin (Ngb) in the pathologic process of contusion and laceration of brain in children.

METHODS

The proteins in the brain tissue were extracted by two-dimensional gel electrophoresis in 3 children undergoing brain ventricular neoplasms resection (normal brain tissue) and in 8 children with contusion and laceration of brain. The image analysis was done using the PDQuest 7.0 software. The differential protein spots were detected and analyzed with Applied Biosystems Voyager System 4307 MALDI-TOF Mass Spectrometer and bioinformatical skills. Ngb expression in the brain tissue was measured using immunohistochemisty. Ngb expression in plasma was measured using ELISA in 15 children with contusion and laceration of brain and 10 healthy children.

RESULTS

Expression maps of the brain tissue were established by two-dimensional gel electrophoresis in children with contusion and laceration of brain and healthy children. Six differential protein spots were found and 5 of them were identified by mass spectrum. Immunohistochemisty assay showed that Ngb expression in the brain tissue in children with contusion and laceration of brain was significantly higher than in normal controls (P<0.05). ELISA results showed that Ngb expression in the plasma increased significantly 6, 12, 18, 24 and 48 hours after trauma in children with contusion and laceration of brain compared with healthy children (P<0.01).

CONCLUSIONS

Ngb may play an important role in the pathologic process of contusion and laceration of brain in children.

Fecal immunochemical tests compared with guaiac fecal occult blood tests for population-based colorectal cancer screening

Colorectal cancer (CRC) is the second most common cause of cancer deaths in Canadian men and women - accounting for almost 12% of all cancer deaths. In Ontario, it is estimated that 8100 persons were diagnosed with CRC in 2011, and 3250 died from the disease. CRC incidence and mortality rates in Ontario are among the highest in the world. Screening offers the best opportunity to reduce this burden of disease. The present report describes the findings and recommendations of Cancer Care Ontario's Fecal Immunochemical Tests (FIT) Guidelines Expert Panel, which was convened in September 2010 by the Program in Evidence-Based Care. The purpose of the present guideline is to evaluate the existing evidence concerning FIT to inform the decision on how to replace the current guaiac fecal occult blood test with FIT in the Ontario ColonCancerCheck Program. Eleven articles were included in the present guideline, comprising two systematic reviews, five articles reporting on three randomized controlled trials, and reports of four other studies. Additionally, one laboratory study was obtained that reported on several parameters of FIT tests that helped to inform the present recommendation. The performance of FIT is superior to the standard guaiac fecal occult blood test in terms of screening participation rates and the detection of CRC and advanced adenoma. Given greater specimen instability with the use of FIT, a pilot study should be undertaken to determine how to implement the FIT in Ontario.

[A study on gene mutation spectrums of α- and β-thalassemias in populations of Yunnan Province and the prenatal gene diagnosis]

OBJECTIVE

To investigate mutation spectrums of α- and β-haemoglobin genes in thalassemia patients and carriers in Yunnan province, and to establish procedures on prenatal gene diagnosis.

METHODS

Totally 10 033 counseling couples and pregnant women, and 22 cases of children with moderate or severe thalassemia were recruited from 5 parts of Yunnan Province, middle, western, eastern, southern and northern areas, during July 2009 to July 2011. Medical records, including results of haemoglobin electrophoresis, blood routine examination, and gene diagnosis of subjects were collected and saved in an database in Excel software by the Key Laboratory for Birth Defects and Genetic Diseases. Using multiple gap-PCR and PCR-reversed dot blotting kits, DNA samples collected from 1077 cases of haematological positive thalassemia patients and carriers were tested to determine common mutations of the α- or β-haemoglobin genes. The codon regions of haemoglobin genes were sequenced by the Sanger sequencing in cases that the mutation tests were negative. Mutation spectrums of α- and β-haemoglobin genes were concluded. Prenatal gene diagnosis was offered to fetuses who had risk of thalassemia major.

RESULTS

(1) In 1077 cases of haemological screen positive subjects, deletions and mutations of α-haemoglobin gene were tested in 119 subjects among 347 cases suspected as α-thalassemia patients and carriers. Five kinds of deletions and mutations on α-haemoglobin gene were found. In 104 subjects, four kinds of common deletions and mutations onα-haemoglobin gene were determined: --(SEA), -α(3.7), α(CS)α, -α(4.2). Other 14 subjects were double heterozygotes with haemoglobin H disease and severe α-thalassemia phenotypes. A rare mutation of insertion and deletion in α2 haemoglobin gene intron, α(301-24_301-23 indel), was found in one carrier subject. (2) In 1077 cases of haemological screen positive subjects, deletions and mutations of β-haemoglobin gene were tested in 297 subjects among 730 cases suspected as β-thalassemia patients and carriers. Sixteen kinds of β-haemoglobin gene mutations were found, including 7 cases of rare abnormal haemoglobinopathy patients with β-haemoglobin gene mutations. In one case with β(+) phenotype patient, the Codon 5(-CT) mutation at β-haemoglobin gene was found (firstly reported in China). (3) Three fetuses with high risks of α-thalassemia were accepted for prenatal diagnosis. One case of Hb Bart's hydrops syndrome fetus with the genotype --(SEA)/--(SEA), and one case of mild α-thalassemia fetus with the genotype α(CS)α/αα were found. Another one fetus was found with normal α-haemoglobin. In 6 fetuses accepted for prenatal diagnosis due to high risks of β-thalassemia, one case of β-thalassemia major with the genotype CD(17)(A→T)/-28(A→G) was found, 3 fetuses were heterozygote carriers, and 2 fetuses had normal genotypes without mutations found in their parents. Medical terminations for 2 fetuses with severe thalassemia were made according to the choice of pregnant women. Other 7 pregnancies continued to term. Anemia or growth retardation was not found in the 7 infants when following up after given-birth 6 to 12 months.

CONCLUSIONS

The mutation spectrums of α- and β-haemoglobin genes of thalassemia patients and carriers in Yunnan province are special, in which β-haemoglobin gene exits more polymorphism in the mutation spectrum. Carrier screening in pregnant women, and offering prenatal gene diagnosis to the high risk pregnancies should be an efficient strategy to prevent thalassemia major.

The β‐Globin Gene Cluster Haplotypes in Sickle Cell Anemia Patients from Northeast Brazil: A Clinical and Molecular View

The beta(S)-globin haplotypes were studied in 78 sickle cell Brazilian patients from Bahia, Northeast Brazil, that has a large population of African origin. Hemoglobin (Hb) profiles were developed by high-performance liquid chromatography (HPLC), and beta(S)-globin gene haplotypes were determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) techniques. We identified 44 (55.0%) patients with the CAR/Ben (Central African Republic/Benin) genotype, 16 (20.0%) Ben/Ben, 13 (16.2%) CAR/CAR and seven (8.8%) with other genotypes. Analyses of the phenotypes showed clinical differences related only to Hb F levels and blood transfusion therapy; the presence of -alpha(-3.7)-thalassemia (thal) demonstrated statistical significance when associated with hematocrit (p=0.044), MCV (p=0.0007), MCH (p=0.012) and spleen sequestration events. The haplotype diversity found in the present study can be justified by information about the origin of the slave traffic period in Bahia during the 19th century. The specific characteristics described among the Bahian sickle cell patients could be confirmed by increasing the number of patients with specific genotypes and further studies of genetic markers.

Quintuple α-Globin Gene: A Novel Allele in a Sudanese Man

Multiple alpha-globin repeats have previously been discovered in humans and other mammals. A quintuple alpha-globin gene (alphaalpha/alphaalphaalphaalphaalpha) was found in a Sudanese male undergoing evaluation for microcytosis.

Fetal and embryonic hemoglobins in erythroblasts from fetal blood and fetal cells enriched from maternal blood in pregnancies complicated by maternal diabetes mellitus

OBJECTIVES

To determine whether there is a delay or reversal in switch mechanisms from embryonic (epsilon and zeta) to fetal (gamma) hemoglobins accompanying the erythroblastosis in fetuses of diabetic mothers, and whether the increased erythroblast count in the fetal blood is associated with an increase in fetomaternal cell trafficking.

MATERIALS AND METHODS

Fetal and maternal blood samples were obtained from 11 fetuses and five pregnant women in pregnancies complicated by maternal diabetes mellitus. Blood samples were also taken as controls from 35 fetuses and 33 mothers. Fetal erythroblasts were isolated by triple density gradient centrifugation and magnetic cell sorting with anti-CD71 antibody. Fluorescent antibodies were used to immunostain for gamma (gamma), epsilon (epsilon) and zeta (zeta) hemoglobin chains. In the maternal samples, fluorescence in situ hybridization for X and Y chromosomes was also carried out, to confirm the presence and proportion of enriched fetal cells from the maternal blood.

RESULTS

In both fetal and maternal blood the median percentages of erythroblasts positive for gamma-globin, epsilon-globin and zeta-globin chains were significantly higher in fetuses of diabetic mothers compared to controls (fetus, gamma-globin, 76 vs. 64%, p < 0.0001; epsilon-globin, 4 vs. 0%, p < 0.0001; zeta-globin, 4 vs. 0%; p < 0.0001; mother, gamma-globin, 14 vs. 1%, p < 0.0005; epsilon-globin, 0.25 vs. 0%, p < 0.0003; zeta-globin, 0.2 vs. 0%, p < 0.0003). The median percentage of cells with Y signals in maternal blood was also higher in diabetic pregnancies compared to normal controls (7.5 vs. 1%, p < 0.002).

CONCLUSIONS

The findings suggest that the fetal erythroblastosis in diabetic pregnancies is accompanied by a delay in the switch from embryonic to fetal hemoglobin chains. In addition, it is associated with an increase in fetomaternal cell trafficking.

β-Thalassemia Due to a Novel Nonsense Mutation at Codon 37 (TGG→TAG) Found in an Afghanistani Family

We have identified and characterized a novel beta-thalassemic mutation in an Afghanistanifamily. The molecular pathology consists of a single base substitution (TGG-->TAG) at codon 37 of the beta-globin gene, giving rise to a stop codon (TAG). Premature stop of translation results in a truncated protein and usually the phenotype of beta-thalassemia (thal) major in homozygous individuals. However, this was not the case in our proband, who was homozygous for the codon 37 mutation. He presented with the phenotype of thalassemia intermedia with a hemoglobin (Hb) level of 8.1 g/dL and no previous history of blood transfusions. High performance liquid chromatography (HPLC) analysis showed exclusively Hb F except for a Hb A2 level within normal limits. Subsequent analysis demonstrated homozygosity for the XmnI Ggamma polymorphism and heterozygosity for a deletional alpha-thal (alphaalpha/-alpha(-3.7)). These findings might, at least partly, explain the beta-thal intermedia phenotype observed in the proband.

Globin Chain Synthesis is a Useful Complementary Tool in the Differential Diagnosis of Thalassemias

The present study aimed at differentiating rare types of heterozygous beta-thalassemia (thal) with normal Hb A(2) values from alpha-thal in Iranian carriers by globin chain synthesis in addition to other hematological parameters. Our study groups consisted of 51 normal subjects, 24 heterozygous beta- thalassemic subjects with high Hb A(2), 62 alpha-thal-2 subjects, 34 alpha-thal-1 subjects, six Hb H disease thalassemic subjects, 14 silent beta-thal subjects with normal Hb A(2) values, five deltabeta-thal subjects and two subjects with an association of alpha- and deltabeta-thal (total = 198). Analysis of globin chains was performed by high performance liquid chromatography (HPLC). The results showed that the alpha/beta ratio averages were close to the ones in the published literature, but with a greater standard deviation and a wider range. Globin chain synthesis (GCS) could be valuable in differentiating between microcytosis produced by silent beta-thal (heterozygous beta-thal with a normal Hb A(2) level) and that caused by alpha-thal. Since the complex genotype/phenotype relationship can lead to diagnostic difficulties, GCS cannot be used as the only diagnostic tool for thalassemia carrier detection. Therefore, a combination of different tests for each patient is required.

Differential expression of I alpha- and II alpha-globin genes in Norwegian dairy goats

Fast protein liquid chromatography (FPLC) and polyacrylamide gel electrophoresis were used to determine the ratio between I alpha- and II alpha-globin chains in Norwegian dairy goats. Three different phenotypes, designated normal (N) with I alpha- to II alpha-globin ratio 3:1, reversed (R) with ratio 1:2 and double-reversed (RR) with no I alpha-globin, were described. Family studies indicated that the R animals were heterozygous, and the RR animal homozygous, for a haplotype without a functional I alpha-globin product. Southern blot analysis of goat DNAs digested with six different restriction enzymes showed that the different ratios of alpha chain expression could not be due to a deletion of the I alpha-gene and/or duplication or triplication of the II alpha-globin genes. The homozygous reversed animal with no detectable I alpha-globin had a mild anaemia.

Efficacy of a modified improved technique for detecting red cell haemoglobin H inclusions

Alpha-thalassaemia is a common disease in Taiwan. A feature useful in diagnosis is the excess of of beta-chains that result from impaired alpha-chain production. These excess chains assemble into beta 4 tetramers (i.e. Hb H) which can be detected by its rapid anodal migration on alkaline electrophoretic media as seen in Hb H disease. However, this technique cannot, and conventional Hb H inclusion staining rarely can visualize alpha-thalassaemic traits due to small quantities of Hb H formed in these patients. The staining for Hb H inclusion bodies uses brilliant cresyl blue (BCB) or methylene blue (MB) as an oxidant to denature Hb H as intracellular inclusions. We have improved the technique of Jones (who modified the original method in order to obtain enriched young red cells) by prolonging the incubation time from 30 min to 3 h. The sensitivity of this modified improved method was 91% for detecting obligatory alpha-thalassaemic traits as shown in table. No false positive results were seen in beta-thalassaemia or in others. We believe this can be used as a confirmatory test in heterozygous alpha 1-thalassaemia and homozygous alpha 2-thalassaemia.

Coupling confocal fluorescence detection and recirculating microfluidic control for single particle analysis in discrete nanoliter volumes

The recent proliferation of platforms designed to handle arrays of nano- and picolitre volumes is in response to the need to perform biological assays on discrete entities, such as single cells. However, a critical challenge associated with this trend for in vitro compartmentalization is the need for highly sensitive, yet low-volume detection platforms. In this paper, we coupled confocal fluorescence detection with recirculating microfluidic control to perform single particle DNA assays within five nL chambers. The performance of this low-volume assay was shown to match that of traditional single molecule detection platforms. However, volume requirements per measurement were nearly 3 orders of magnitude less than conventional systems, enabling future integration with lab-on-a-chip systems that require discrete or digitalized sample processing.

Characterization of DESI-FTICR mass spectrometry - from ECD to accurate mass tissue analysis

Implementation of desorption electrospray ionization (DESI) technique on a 9.4 T Fourier transform ion cyclotron resonance (FTICR) mass spectrometer is described. Desorption electrospray technique is capable of the direct investigation of natural samples without any need for sample preparation or chromatographic separation. Since the DESI mass spectra of natural samples are very complex owing to the lack of preseparation or cleanup, the ideal mass spectrometric analyzer for these applications is a high-resolution instrument such as FTICR mass spectrometer. DESI was implemented by constructing an electronically controlled source framework comprising six linear moving stages and one rotating stage. A three-dimensional linear stage was used to accommodate samples, while another 3D linear stage equipped with rotating stage was used as a spray mount. A modified electrosonic sprayer was used as a primary electrospray device. DESI-FTICR setup was characterized with regard to geometrical, electrical and flow conditions using deposited peptide samples in range of 1-100 pmol gross deposited amount on glass and polymer surfaces. Optimized conditions enabled the routine acquisition of DESI-MS spectra on the instrument at 130 000 resolution in the broadband mode and with comparable sensitivity to data reported in the literature. Since the main significance of DESI-FTICR MS is the combination of intact tissue analysis, the capabilities of the technique were demonstrated by analyzing murine liver samples. Presence of lysophospholipids in the liver tissue was tentatively associated with the lipid metabolism taking place in liver. DESI-FTICR is also a promising technique in the field of peptide analysis due to capability of top-down sequencing using electron capture dissociation. As a proof-of-principle experiment, a small synthetic polypeptide containing 36 amino acids was ionized using DESI and was sequenced in the FTICR by means of ECD (electron capture dissociation) fragmentation. Spectra gave almost full sequence information in agreement with the known amino acid sequence of the species.

Inosine-containing dsRNA binds a stress-granule-like complex and downregulates gene expression in trans

Long double-stranded RNAs (dsRNAs) may undergo extensive modification (hyperediting) by adenosine deaminases that act on RNA (ADARs), where up to 50% of adenosine (A) residues are changed to inosine (I). Traditionally, consequences of A-to-I editing were thought to be limited to modified RNA itself. We show here, however, that hyperedited dsRNA (I-dsRNA) is able to downregulate gene expression in trans. Furthermore, we show that both endogenous expression and reporter gene expression were substantially reduced in the presence of I-dsRNA. This was due to a reduction in reporter mRNA levels and also translation inhibition. Importantly, we show that I-dsRNA interferes with translation initiation. We also show that I-dsRNA specifically binds a stress-granule-like complex. Stress granules (SGs) are important for translational silencing during stress. Finally, we propose a model whereby editing by ADARs results in downregulation of gene expression via SG formation.

[Histological alterations in the liver and increased serum proteins in chickens fed with diet containing Saccharomyces cerevisiae]

The aim of this study was to determine the effect of diet supplemented with Saccharomyces cerevisiae (SC), on the liver morphology, serum activities of aspartateaminotrasferase (AST) and alanineaminotransferase (ALT), and the serum concentration of total proteins, albumin and the different fractions (alpha, beta, gamma) of globulin in chickens. Two groups of Hubbar x Hubbar strain chickens (each = 16), were fed with a diet T1 (commercial food without SC) and T2 (commercial food with SC) for 42 days. Thereafter, animals were sacrificed and samples of blood and liver were obtained. Macroscopic features and relative weight of livers remained in the normal ranges in both groups. High percent of T2 chickens (p < 0.05) showed hepatic alterations with proliferation/dilation of biliary ducts and increased degree of vacuolization. Tricromic stain showed elevated perivascular fibrosis in T2. The ultrastructural study showed fibroblast like cells, increased amount of collagen fibers, cytoplasm vacuolization of hepatocytes and loss of cellular and mitochondrial integrates. No significant differences were observed in the activities of AST and ALT between groups. Increased concentrations of total proteins and alpha2, beta and gamma globulins and decreased albumin were observed in the serum of T2 group. These findings may be related to a hepatotoxic effect of SC and chickens could have the risk of further increased hepatic failure with a prolonged exposition to this diet.

Quantification of Hemoglobin A2 by Tandem Mass Spectrometry

Background: Peptide-based analysis of whole blood using electrospray tandem mass spectrometry (MSMS) in multiple reaction monitoring (MRM) mode enables rapid detection and sequence confirmation of clinically significant hemoglobin (Hb) variants. We applied a similar, quantitative approach to the measurement of δ:β-globin peptide ratios as potential surrogate markers of HbA2, a biomarker used in population screening for β-thalassemia trait.

Methods: We studied 163 blood samples with normal HbA2 (%), 105 with increased HbA2, 43 with δ-chain variants, and 8 with Hb Lepore. All were tested by HPLC. The samples were also incubated with trypsin for 30 min at 37 °C for MSMS with flow injection analysis. MRMs for the δ- (T2, T3, and T14) and β- (T2, T3, and T13) globin tryptic peptides were acquired for 1 min, and δ:β peptide ratios were calculated. We used HPLC and MSMS to analyze 26 paired whole blood and dried blood spot samples after storage for 1, 8, and 29 days.

Results: Within- and between-assay imprecision values (CVs) were &lt;6.1% and &lt;8.4%, respectively, for the δ:β peptide ratios. Digests were stable at 10 °C for 6 days. Significant correlations (P &lt;0.0001) between MSMS δ:β-globin peptide ratios and HPLC HbA2 allowed differentiation between increased HbA2 concentrations and concentrations within the reference interval and identification of Hb Lepore. This differentiation was repeatable by MSMS, but not by HPLC, after blood spot samples had been stored for 1 month.

Conclusion: This study validates the quantitative δ:β-globin peptide ratio as a surrogate marker of HbA2 and demonstrates the potential of rapid peptide-based MSMS for multiplexed, high-throughput protein biomarker characterization and quantification.

Multivariate analysis of matrix-assisted laser desorption/ionization mass spectrometric data related to glycoxidation products of human globins in nephropathic patients

To clarify the possible pathogenetic role of oxidation products originated from the glycation of proteins, human globins from nephropathic patients have been studied by matrix-assisted laser desorption/ionization mass spectrometry (MALDI), revealing not only unglycated and monoglycated globins, but also a series of different species. For the last ones, structural assignments were tentatively done on the basis of observed masses and expectations for the Maillard reaction pattern. Consequently, they must be considered only propositive, and the discussion which will follow must be considered in this view. In our opinion this approach does not seem to compromise the intended diagnostic use of the data because distinctions are valid even if the assignments are uncertain. We studied nine healthy subjects and 19 nephropathic patients and processed the data obtained from the MALDI spectra using a multivariate analysis. Our results showed that multivariate analytical techniques enable differential aspects of the profile of molecular species to be identified in the blood of end stage nephropathic patients. A correct grouping can be achieved by principal component analysis (PCA) and the results suggest that several products involved in carbonyl stress exist in nephropathic patients. These compounds may have a relevant role as specific markers of the pathological state.

Hemoglobin variants and disease manifestations in severe falciparum malaria

CONTEXT

The geographical distributions of hemoglobin S (HbS), hemoglobin C (HbC), and alpha+-thalassemia (-alpha) strongly suggest balancing selection with malaria. However, whereas several studies indicate that the HbS carrier state protects against all major forms of clinical malaria, malaria protection on clinical grounds has been more difficult to confirm for HbC and -alpha, and questions remain as to whether it applies to all forms of the disease.

OBJECTIVE

To assess the association between major clinical forms of severe falciparum malaria and HbS, HbC, and -alpha.

DESIGN, SETTING, AND PARTICIPANTS

Case-control study of 2591 children with severe falciparum malaria enrolled at a tertiary referral center in Ghana, West Africa, and 2048 age-, sex-, and ethnicity-matched control participants recruited by community surveys.

MAIN OUTCOME MEASURES

Frequencies of HbS, HbC, and -alpha in patients and controls, including stratifications of patients for signs of disease.

RESULTS

Patients presented with partly overlapping signs of disease, including severe anemia (64%), cerebral malaria (22%), respiratory distress (30%), hyperparasitemia (32%), prostration (52%), acidosis (59%), and hyperlactatemia (56%). Carrier states of HbS, HbC, and -alpha were found in 1.4%, 9.4%, and 25.2% of the patients, respectively, and 14.8%, 8.7%, and 27.3% of controls. The HbS carrier state was negatively associated with all forms of the disease studied (overall odds ratio [OR], 0.08; 95% confidence interval [CI], 0.06-0.12). The HbC carrier state showed a negative association selectively with cerebral malaria (OR, 0.64; 95% CI, 0.45-0.91), and the -alpha carrier state showed a negative association selectively with severe anemia (OR, 0.82; 95% CI, 0.69-0.96).

CONCLUSION

Whereas the HbS carrier state was found to be negatively associated with all major forms of severe falciparum malaria, the negative associations of the carrier states of HbC and -alpha appeared to be limited to cerebral malaria and severe anemia, respectively.

An improved flow cytometric approach for isolation of fetal cells from maternal blood for non invasive prenatal diagnosis of hemoglobinopathies

Prenatal diagnosis is an option for couples at risk of having a child affected with hemoglobinopathies. Chorionic villus sampling (CVS) and cordocentesis are accurate but a finite risk of fetal loss exists. A non invasive, risk free strategy that has emerged is isolation of fetal erythroblasts from maternal blood. Enrichment of nucleated red blood cells (nRBCs) from 7.0 mL maternal blood was done using a Percoll discontinuous density gradient and isolation by flow sorting using a combination of three monoclonal antibodies: CD45 per CP, glycophorin A-phycoerythrin (PE) and Hb F-fluorescein isothiocyanate (FITC) in 43 cases between 7 and 21 weeks' gestation. The percentage of nRBCs ranged from 0.0001-2.03%. The presence of dual fluorescence (glycophorin A-PE and Hb F-FITC) was confirmed by confocal microscopy. A sufficient number of nRBCs could be isolated in the first and second trimester of pregnancy to provide a simple flow cytometric approach as a potential for non invasive diagnosis of beta-globin defects.

Human placental lactogen is a first-trimester maternal serum marker of Down syndrome

BACKGROUND

Human placental lactogen (hPL) is synthesised by the placenta and found in maternal serum. We analysed the potential of hPL as a first-trimester maternal serum-screening marker for fetal Down syndrome (DS).

MATERIALS AND METHODS

hPL was quantified by ELISA in 47 DS pregnancies and 136 controls in gestational weeks 8-13. Distributions of log multiples of the median (MoMs) were established. The quantity of hPL in DS screening was estimated using Monte Carlo simulation methods.

RESULTS

The mean log10 MoM hPL was - 0.1995 (SD: 0.1993) in affected and 0.0026 (SD: 0.2129) in control pregnancies. This corresponds to a MoM of 0.63 in DS pregnancies. hPL correlated significantly with log10 MoM values of hCGbeta (r = 0.320) and PAPP-A (r = 0.590) in controls, but not with hCGbeta (r = 0.228) or PAPP-A (r = 0.090) in DS pregnancies. The inclusion of hPL in the double test (PAPP-A + hCGbeta) increased the detection rate from 67 to 75% for a false-positive rate of 5%.

CONCLUSION

hPL is a DS screening marker that is applicable at weeks 9-13 and could be included in multiple marker first-trimester screening for DS.

A potential biomarker in the cord blood of preterm infants who develop retinopathy of prematurity

Preterm infants are at risk of developing sepsis, necrotizing enterocolitis (NEC), chronic lung disease (CLD), and retinopathy of prematurity (ROP). We used high-throughput mass spectrometry to investigate whether cord blood proteins can be used to predict development of these morbidities. Cord blood plasma from 44 infants with a birth weight of <1500 g was analyzed by surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF). Six infants developed ROP >or=stage II, 10 CLD, three sepsis, and one NEC. We detected 814 protein signals representing 330 distinct protein species. Nineteen biomarkers were associated with development of >or=stage II ROP [false-discovery rate (FDR) <5%] and none with CLD. Several proteins with molecular weight (Mr) 15-16 kD and pI 4-5 were detected with increased abundance in infants with ROP, while similar Mr proteins with pI 7-9 were less abundant in these patients. Sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and sequence analysis identified these proteins as alpha-, beta-, and gamma-globin chains. Partial deamidation of Asn139 in beta-globin chains was observed only in the pI 4-5 proteins. We conclude that there are several promising biomarkers for the risk of ROP. Deamidation of globin chains is especially promising and may indicate underlying prenatal pathologic mechanisms in ROP. Validation studies will be undertaken to determine their clinical utility.

Characterization of vitamin A-storing cells in mouse fibrous kidneys using Cygb/STAP as a marker of activated stellate cells

The expression of the cytoglobin/stellate cell activation-associated protein (Cygb/STAP) was recently confirmed in all splanchnic vitamin A-storing cells--including hepatic stellate cells (HSCs)--in normal conditions. In the hepatic fibrous lesion, the expression of Cygb/STAP has been shown to be upregulated in activated HSCs and myofibroblasts (MFs), which have synthesized extracellular matrices. Furthermore, splanchnic vitamin A-storing cells have been reported to be distributed in the kidney. In this study, we clarify the contribution of vitamin A-storing cells to renal fibrosis by focusing on Cygb/ STAP. Adult mice were subjected to unilateral ureteral obstruction (UUO) and kidneys were harvested 1, 3, 7, and 10 days after UUO. Numbers of Cygb/STAP-immunopositive cells as well as Cygb/STAP mRNA 3 days after UUO (UUO day 3 kidney) increased. Vitamin A-autofluorescence was observed in intertubular spaces of controls but gradually declined in a time-dependent manner after UUO. Cygb/STAP+ cells were not completely identical with alpha-smooth muscle actin (alphaSMA)-positive cells in the control or UUO day 7 kidneys. Immunohistochemical analysis for Cygb/STAP and fibulin-2 (Fib), a specific marker for distinguishing MFs from activated HSCs, revealed that the number of Fib+STAP+ cells (MFs) and Fib-STAP+ cells (splanchnic vitamin A-storing cells) significantly increased in UUO day 3 and UUO day 7 kidneys compared with the controls. Our present findings support the concept that Cygb/STAP can be a unique marker for splanchnic fibroblast-like cells, namely the vitamin A-storing cell lineage, and suggest that splanchnic vitamin A-storing cells contribute to renal fibrogenesis in the obstructed kidney.

Maturation and enucleation of primitive erythroblasts during mouse embryogenesis is accompanied by changes in cell-surface antigen expression

Primitive erythroblasts (EryPs) are the first hematopoietic cell type to form during mammalian embryogenesis and emerge within the blood islands of the yolk sac. Large, nucleated EryPs begin to circulate around midgestation, when connections between yolk sac and embryonic vasculature mature. Two to 3 days later, small cells of the definitive erythroid lineage (EryD) begin to differentiate within the fetal liver and rapidly outnumber EryPs in the circulation. The development and maturation of EryPs remain poorly defined. Our analysis of embryonic blood at different stages reveals a stepwise developmental progression within the EryP lineage from E9.5 to E12.5. Thereafter, EryDs are also present in the bloodstream, and the 2 lineages are not easily distinguished. We have generated a transgenic mouse line in which the human epsilon-globin gene promoter drives expression of green fluorescent protein exclusively within the EryP lineage. Here, we have used this line to characterize changes in cell morphology and surface-marker expression as EryPs mature and to track EryP numbers and enucleation throughout gestation. This study identifies previously unrecognized synchronous developmental stages leading to the maturation of EryPs in the mouse embryo. Unexpectedly, we find that EryPs are a stable cell population that persists through the end of gestation.

Augmentation de l’hémoglobine A2 au cours du pseudoxanthome élastique

BACKGROUND

Pseudoxanthoma elasticum (PXE) is normally associated with mutations in the ABCC6 gene. A PXE phenotype without mutations in ABCC6 has been described in Greek and Italian patients presenting with beta thalassemia. We attempted to determine the incidence of beta thalassemia in a cohort of French patients with PXE.

PATIENTS AND METHODS

Fifty patients with PXE were included in the study. Laboratory examinations comprised hemoglobin electrophoresis, ABCC6 gene study and in some studies: mutation analysis, beta-globin gene.

RESULTS

No cases of beta thalassemia were diagnosed in this cohort of French patients with PXE. However, 20% of the latter exhibited a significant but isolated (i.e. without microcytic anemia) increase of hemoglobin A2 (HbA2). Statistical comparisons showed no difference in terms of geographical origin or severity of PXE between patients with high levels of HbA2 and those with normal levels of HbA2 other than the extent of cutaneous involvement. Study of the beta-globin gene displayed mutations only in the two patients with the highest recorded levels of HbA2. ABCC6 + beta-globin digenism was ruled out of the pathogenesis of PXE.

DISCUSSION

The PXE phenotype seen in some patients with beta thalassemia appears to be associated with epigenetic modification of ABCC6 transcription and depends specifically on the beta globin locus. Isolated increase in HbA2 is probably a laboratory marker for PXE. Here again, a functional epigenetic reaction between ABCC6 and the beta-globin locus was suspected. However, these reciprocal interactions are clearly unequal since the change in ABCC6 transcription occurring during the course of beta thalassaemia is responsible for a PXE phenotype while increased HbA2 during the course of PXE has no clinical consequences.

The beta-globin gene haplotypes associated with Hb D-Los Angeles [beta121(GH4)Glu --> Gln] in Western Iran

Hb D-Los Angeles is characterized by the substitution of glutamine for glutamic acid at position 121 of the beta-globin chain. The present investigation is the first study on the beta-globin gene haplotypes associated with beta-D-Los Angeles in Western Iran. Thirty two individuals from 11 unrelated families from Western Iran were studied. The Hb D-Los Angeles status of all cases was confirmed using polymerase chain reaction (PCR) followed by digestion with EcoRl. The haplotype of the beta-globin gene cluster was determined by a PCR-RFLP (restriction fragment length polymorphism) procedure. The haplotype background of the betaA chromosomes was also determined in 35 normal subjects from the same geographic region. The beta-globin gene haplotype analysis demonstrated that all beta-D-Los Angeles genes (23 genes) were in linkage disequilibrium with haplotype I [+----++]. Among the 70 betaA chromosomes, 30 chromosomes (42.9%) were associated with haplotype I. The present study indicates the unicentric origin of the beta-D-Los Angeles gene in Western Iran. It seems that this mutation may have occurred at the same chromosomal background common in the local population.

Circulating cell-free fetal messenger RNA levels after fetoscopic interventions of complicated pregnancies

OBJECTIVE

The aim of this study was to examine fetal gene expression in maternal plasma after fetoscopic intervention for twin-twin transfusion syndrome or congenital diaphragmatic hernia.

STUDY DESIGN

Twelve women with pregnancies that were complicated by twin-twin transfusion syndrome and 10 women carrying fetuses with congenital diaphragmatic hernia were sampled before and sequentially after treatment. Levels of glyceraldehyde-3-phosphate dehydrogenase, human placental lactogen, and gamma globin messenger RNA were measured by real-time reverse transcriptase polymerase chain reaction amplification.

RESULTS

At all time points, glyceraldehyde-3-phosphate dehydrogenase messenger RNA levels were higher in the congenital diaphragmatic hernia cases than in the twin-twin transfusion syndrome cases (P < .05), but during the immediate postoperative observation period, there were no significant changes in glyceraldehyde-3-phosphate dehydrogenase, human placental lactogen, or gamma globin messenger RNA levels in individual patients or patients who were grouped by procedure.

CONCLUSION

Fetoscopic intervention of complicated pregnancies does not affect circulating fetal messenger RNA levels, which is in contrast to earlier observations that circulating fetal DNA levels increase after laser ablation for twin-twin transfusion syndrome. Plasma glyceraldehyde-3-phosphate dehydrogenase messenger RNA levels could be a potential novel biomarker for fetal trauma.

Fucosylated haptoglobin is a novel marker for pancreatic cancer: a detailed analysis of the oligosaccharide structure and a possible mechanism for fucosylation

Changes in oligosaccharide structures have been reported in certain types of malignant transformations and, thus, could be used for tumor markers in certain types of cancer. In the case of pancreatic cancer cell lines, a variety of fucosylated proteins are secreted into their conditioned media. To identify fucosylated proteins in the serum of patients with pancreatic cancer, we performed western blot analyses using Aleuria Aurantica Lectin (AAL), which is specific for fucosylated structures. An approximately 40 kD protein was found to be highly fucosylated in pancreatic cancer and an N-terminal analysis revealed that it was the beta chain of haptoglobin. While the appearance of fucosylated haptoglobin has been reported in other diseases such as hepatocellular carcinoma, liver cirrhosis, gastric cancer and colon cancer, the incidence was significantly higher in the case of pancreatic cancer. Fucosylated haptoglobin was observed more frequently at the advanced stage of pancreatic cancer and disappeared after an operation. A mass spectrometry analysis of haptoglobin purified from the serum of patients with pancreatic cancer and the medium from a pancreatic cancer cell line, PSN-1, showed that the alpha 1-3/alpha 1-4/alpha 1-6 fucosylation of haptoglobin was increased in pancreatic cancer. When a hepatoma cell line, Hep3B, was cultured with the conditioned media from pancreatic cancer cells, haptoglobin secretion was dramatically increased. These findings suggest that fucosylated haptoglobin could serve as a novel marker for pancreatic cancer. Two possibilities were considered in terms of the fucosylation of haptoglobin. One is that pancreatic cancer cells, themselves, produce fucosylated haptoglobin; the other is that pancreatic cancer produces a factor, which induces the production of fucosylated haptoglobin in the liver.

The effect of VEGF on blood vessels and blood cells during Xenopus development

Vascular endothelial growth factor (VEGF) is known to play an essential role in vascular development. We have overexpressed VEGF122 or VEGF170, which are equivalent to mouse VEGF120 and VEGF164, in developing Xenopus embryos. Overexpression of VEGF170 but not VEGF122 demonstrated an absence of expression of hematopoietic markers alpha-globin and GATA-1 but only in the posterior portion of the blood island. Interestingly, strong signals of endothelial markers, msr, fli-1, and tie-2, were detectable in those regions, instead of hematopoietic markers. These results suggested both that injection of VEGF170 resulted in disturbance of vasculogenesis in the posterior portion of the blood island, with excessive production of endothelial cells at the expense of blood cells, and that the anterior and posterior portions of the VBI may have distinct characteristics.

Investigations of a human embryonic globin gene silencing element using YAC transgenic mice

A silencing element has been previously located upstream of the human epsilon-globin gene promoter using transient assays and transgenic mice carrying plasmid constructs in which the element has been deleted or its transcriptional motifs have been mutated. To investigate whether this element functions in the context of the whole beta-globin locus, we analyzed epsilon-globin gene expression in transgenic mice carrying a deletion of the silencing element in the context of a 213-kilobase human beta-globin yeast artificial chromosome (beta-YAC). epsilon-Globin gene expression was measured during embryonic and fetal development and in adult mice. epsilon-mRNA levels in embryonic cells in Day 12 blood were as high as those measured in wild-type beta-YAC controls, indicating that the deletion does not affect epsilon gene promoter function. epsilon-Globin gene expression was confined to the embryonic cells, indicating that deletion of this silencing element did not affect epsilon-globin developmental expression in the context of the beta-YAC. These results suggest that in the context of the whole beta-globin locus, other proximal and upstream epsilon gene promoter elements as well as competition by the downstream globin genes contribute to the silencing of the epsilon-globin gene in the cells of definitive erythropoiesis.

Use of the hereditary persistence of fetal hemoglobin 2 enhancer to increase the expression of oncoretrovirus vectors for human gamma-globin

The development of oncoretrovirus vectors for human gamma-globin has been hampered by problems of low expression and gene silencing. In order to address these problems, we investigated an enhancer element identified from individuals with deletional hereditary persistence of fetal hemoglobin 2 (HPFH2), a genetic condition characterized by elevated levels of gamma-globin in adults. Plasmid transfection studies in erythroid MEL (murine erythroleukemia) cells demonstrated the HPFH2 element could function synergistically with the beta-globin locus control region to enhance the expression of an Agamma-globin gene with a truncated -382 bp promoter. A series of oncoretrovirus vectors were subsequently generated that contain an expression cassette for Agamma-globin linked to various combinations of the HPFH2 enhancer, the alpha-globin HS40 enhancer, and several versions of the promoter from Agamma-globin or beta-globin. Expression analysis in transduced MEL cell clones revealed very high levels of promoter-autonomous silencing that was at least partially abrogated by the HPFH2 enhancer. The vector containing a combination of a -201 bp Agamma-globin gene promoter with the Greek HPFH -117 point mutation and both the HPFH2 and HS40 enhancers exhibited no signs of vector silencing and was expressed at 248+/-99% per copy of mouse alpha-globin (62% of total alpha-globin). This represents a significant improvement over previously reported oncoretrovirus vectors for Agamma-globin, and demonstrates the capacity of the HPFH2 enhancer to abrogate sequence-autonomous silencing of the Agamma-globin promoter in the context of a gene transfer vector.

Automated method for measuring globin adducts of acrylamide and glycidamide at optimized Edman reaction conditions

The general population is exposed to acrylamide, a potential human carcinogen, through food and cigarette smoke. The assessment of human exposure to acrylamide is important in the evaluation of health risks associated with this chemical. Hemoglobin adducts of acrylamide (AA-Hb) and its primary metabolite glycidamide (GA-Hb) are established biomarkers of acrylamide exposure and methods to measure these biomarkers using modified Edman reaction are described. Only limited information about the optimal Edman reaction conditions such as pH or temperature is available for these adducts and the existing methods do not allow automation needed in biomonitoring studies. In this study, the yield of Edman products of AA-Hb and GA-Hb between pH 3-10 and at 35-55 degrees C at different time intervals, and the applicability of liquid-liquid extraction on diatomaceous earth for analyte extraction, were assessed and results were used in a new optimized method. The applicability of our optimized method was assessed by comparing results obtained with a convenience sample from 96 individuals with a conventional method. Maximum yield of Edman products was obtained between pH 6-7, heating the reaction solution at 55 degrees C for 2 h resulted in the same yields as with conventional conditions, and use of diatomaceous earth was found suitable for automated analyte extraction. Using these conditions, no difference was observed between our optimized and a conventional method. The median globin adduct values in the convenience sample are 129 pmol/g globin (range: 27-453 pmol/g globin) and 97 pmol/g globin (range: 27-240 pmol/g globin) for AA-Hb and GA-Hb, respectively. The GA-Hb/AA-Hb ratio decreases significantly with increasing AA-Hb values indicating that measurement of AA-Hb as well as GA-Hb are needed to appropriately assess human exposure to acrylamide.

Dietary Copper Enhances the Peripheral Myelinopathy Produced by Oral Pyrrolidine Dithiocarbamate

The neurotoxic hazard of a dithiocarbamate is influenced by route of exposure and acid stability of the dithiocarbamate. As an example, oral administration of the acid labile dithiocarbamate N,N-diethyldithiocarbamate (DEDC) causes a central-peripheral axonopathy thought to result from acid-promoted decomposition to CS2 in the stomach. In contrast, parenteral administration of DEDC, which bypasses the acidic environment of the stomach, causes a primary demyelination that is thought to be mediated through the intact parent dithiocarbamate. The relative acid stability of pyrrolidine dithiocarbamate (PDTC) suggests that a significant portion of a dose can be absorbed intact following oral exposure with the potential to produce a primary myelin injury. The present study was performed to characterize the neurotoxicity of PDTC and evaluate the possible role of copper in dithiocarbamate-mediated demyelination. Male Sprague Dawley rats were administered PDTC in drinking water and given either a normal- or high-copper diet for 18, 47, or 58 weeks. Examination of peripheral nerve by light microscopy and electron microscopy at the end of exposures revealed primary myelin lesions and axonal degeneration in the PDTC groups, with a significant increase in the severity of several lesions observed for the PDTC, high-copper group relative to the PDTC normal-copper diet. ICP-AES metal analysis determined that the PDTC groups had significantly increased brain copper, and at 58 weeks a significant increase in copper was seen in the sciatic nerve of PDTC high-copper animals relative to PDTC normal-copper diet animals. Although RP-HPLC analysis could not detect globin alkylaminocarbonyl cysteine modifications analogous to those seen with parenteral DEDC, LC/MS/MS identified (pyrrolidin-1-yl carbonyl)cysteine adducts on PDTC-exposed rat globin. These findings are consistent with previous studies supporting the ability of acid-stable dithiocarbamates to mediate myelin injury following oral exposure. The greater severity of lesions associated with dietary copper supplementation and elevated copper levels in nerve also suggests that perturbation of copper homeostasis may contribute to the development of myelin lesions.

Molecular Strategies for Identifying Human Papillomavirus Infection in Routinely Processed Samples: Focus on Paraffin Sections

OBJECTIVE

To optimize the protocols of human papillomavirus (HPV) detection in clinical samples, we used polymerase chain reaction (PCR)-based techniques in paraffin-embedded tissue sections and compared the results with those obtained with PCR and Hybrid Capture II (HC2) performed in liquid-based cytology (LBC) preservation medium.

MATERIALS AND METHODS

Forty-five consecutive cervical biopsy specimens were taken from women participating in the ongoing Latin American Screening Study at Leonor Mendes de Barros Hospital, São Paulo, Brazil, during 2003 and 2004. The biopsy specimens were analyzed for HPV by a modified GP5+/GP6+ PCR protocol, and the results were compared with those obtained by PGMY PCR and HC2 in samples collected in LBC preservation medium.

RESULTS

beta-Globin was detected in 100% of the multiplex PCR system from LBC samples and 66.7% with PCO4+/PCO3+ PCR in biopsy specimens. Of the three methods, PGMY PCR system and HC2 were equally effective in detecting HPV; both detected 13 cases in 45 samples (28.9%). The GP5+/GP6+ PCR applied in biopsy specimens showed a 20% HPV detection rate (9/45).

CONCLUSIONS

Our PCR protocols worked reasonably well and allowed us to compare the three molecular methods with histological and cytological findings. The reproducibility of the results makes the technique applicable in archival materials.

Quantification of HFV-integrated DNA in human cells by Alu-LTR real-time PCR

Integration is described as a key step in viral replication of all retroviruses. A sensitive and quantitative measure of an integrated molecule is a good way to examine the importance of the integration step and to evaluate efficiency of retroviral vectors for gene transfer or anti-integrase drugs. Here, we report a sensitive and quantitative real-time polymerase chain reaction (PCR) technique to measure integrated viral DNA in human cells during a foamy virus (HFV) infection. This technique is based on two steps of PCR. The first round amplifies Alu-LTR (long terminal repeat) sequences resulting from viral integration. The second round of PCR is performed to quantify these events of integration. Quantification is monitored by the comparison of the amplification curve of the sample against a standard scale constituted of viral DNA from chronically infected cells. Sensitivity of this technique allows us to detect as few as 25 copies of HFV-integrated DNA in 50,000 cells.

Structural divergence and distant relationships in proteins: evolution of the globins

The globin family has long been known from studies of approximately 150-residue proteins such as vertebrate myoglobins and haemoglobins. Recently, this family has been enriched by the investigation of the sequences and structures of truncated globins, which have the same basic topology but are approximately 30 residues shorter and exhibit functions other than the familiar one of binding diatomic ligands. The divergence of protein sequences, structures and functions reveals Nature's exploration of the potential inherent in a folding pattern, that is, the topology of the native structure. The observation of what remains constant and what varies during the evolution of a protein family reveals essential features of structure and function. Study of proteins with a wide range of divergence can therefore sharpen our understanding of how different amino acid sequences can determine similar three-dimensional structures. Globins have provided, and continue to provide, interesting material for such studies.

A rare association of alphaO-thalassemia (--SEA) and an initiation codon mutation (ATG-->A-G) of the alpha2 gene causes Hb H disease in Thailand

Several rare and hitherto unidentified non deletional alpha-thalassemias (alphaTalpha or alphaalphaT) have been reported from Thailand within the past few years. Interactions of these determinants with alphaO-thalassemia (thal) (--/), which is highly prevalent in this region, give rise to various genotypes (--/ alphaTalpha or --/alphaalphaT) underlying Hb H disease. We report herein the interaction of a rare initiation codon mutation of the alpha2 gene and alphaO-thal in a Thai boy with Hb H disease. This finding highlights a wide variety of molecular pathology of the alpha-globin genes underlying alpha-thal syndrome in Southeast Asia.

A novel role for Vpr of human immunodeficiency virus type 1 as a regulator of the splicing of cellular pre-mRNA

Vpr, one of the accessory gene products of human immunodeficiency virus type 1 (HIV-1), affects aspects of both viral and cellular proliferation, being involved in long terminal repeat (LTR) activation, arrest of the cell cycle at the G2 phase, and apoptosis. We have discovered a novel role for Vpr as a regulator of the splicing of pre-mRNA both in vivo and in vitro. We found, by RT-PCR and RNase protection analysis, that Vpr caused the accumulation of incompletely spliced forms of alpha-globin 2 and beta-globin pre-mRNAs in cells that had been transiently transfected with a Vpr expression vector. We postulated that this novel effect of Vpr might occur via a pathway that is distinct from arrest of the cell cycle at G2. By analyzing splicing reactions in vitro, we showed that Vpr inhibited the splicing of beta-globin pre-mRNA in vitro. The splicing of intron 1 of alpha-globin 2 pre-mRNA was modestly inhibited by Vpr but the splicing of intron 2 was unaffected. Interestingly, an experimental infection system which utilizes high-titered HIV-1/vesticular stomatitis virus G protein showed that Vpr expressed from an HIV-1 provirus was sufficient to accumulate endogenous alpha-globin 2 pre-mRNA. Thus, it is likely that Vpr contributes to selective inhibition of the splicing of cellular pre-mRNA.

Predicting clinical severity in sickle cell anaemia

The ability to predict the phenotype of an individual with sickle cell anaemia would allow a reliable prognosis and could guide therapeutic decision making. Some risk factors for individual disease complications are known but are insufficiently precise to use for prognostic purposes; predicting the global disease severity is not yet possible. Genetic association studies, which attempt to link gene polymorphisms with selected disease subphenotypes, may eventually provide useful methods of foretelling the likelihood of certain complications and allow better individualized treatment.

Fetal cells in maternal blood: a comparison of methods for cell isolation and identification

OBJECTIVE

A variety of methods have been used to select and identify fetal cells from maternal blood. In this study, a commonly used 3-step selection method is compared with selection directly from whole blood. Identification of fetal origin by XY FISH of male cells was also evaluated.

METHODS

Maternal blood was drawn either before invasive chorion villus sampling (pre-CVS) or after (post-CVS) from women carrying a male fetus. Fetal cells were isolated either by density gradient centrifugation succeeded by CD45/CD14 depletion and CD71-positive selection from CD45/CD14-negative cells, or by CD71-positive selection directly from whole blood. The true origin of fetal cells recovered by the two methods was established by two rounds of XY chromosome FISH in reverse colors, in some instances combined with anti-zeta (zeta) or anti-zeta/anti-gamma (gamma) antibody staining.

RESULTS

In blood samples taken post-CVS and enriched by CD71 selection directly from whole blood, fetal cells were identified with a frequency that was almost four orders of magnitude higher than in post-CVS samples enriched by the 3-step method. In blood samples taken pre-CVS and enriched by the 3-step procedure, no fetal cells were identified by reverse color FISH in 371 ml of blood. In similar samples enriched by CD71 selection on whole blood, two fetal cells were identified in 27 ml of blood. Rehybridization with X and Y chromosome probes with reverse colors was necessary to exclude false Y chromosome signals. Not all fetal cells identified by the presence of a true Y chromosome signal stained with anti-zeta antibody.

CONCLUSIONS

Selection of fetal NRBCs from maternal blood by CD71-positive selection directly from whole blood is superior to density gradient centrifugation succeeded by CD45/CD14 depletion and CD71 selection of CD45/CD14-negative cells. Combining two markers for fetal origin is recommended for unambiguously identifying a cell as fetal.

The poly(A)-limiting element enhances mRNA accumulation by increasing the efficiency of pre-mRNA 3' processing

The poly(A)-limiting element (PLE) is a conserved sequence originally found in the 3' UTR of Xenopus albumin mRNA whose presence restricts the length of the poly(A) tail on both pre-mRNA and fully processed mRNA to <20 nt. Results presented in this study show that the PLE also increases the cytoplasmic level of reporter beta-globin mRNA. Transcription run-on shows this increase was not due to increased reporter gene transcription, and experiments with tetracycline repressor-controlled reporter mRNA showed the PLE does not alter the rate of mRNA decay. Both RT-PCR and RNase protection assay showed the PLE caused a 50% increase in the 3' processing of reporter beta-globin mRNA in vivo. This was confirmed in vitro, where PLE-containing RNA was cleaved in HeLa nuclear extract at a rate 80% faster than a control RNA bearing an inactive element. These results indicate that the PLE regulates the length of the poly(A) tail and the efficiency of 3' processing. In addition, they show that PLE-containing mRNA with a <20-nt poly(A) tail is as stable as mRNA with a 100- to 200-nt poly(A) tail.