Major hematologic diseases in the developing world- new aspects of diagnosis and management of thalassemia, malarial anemia, and acute leukemia

Association between hemoglobin variants and laboratory outcomes in patients infected with P. falciparum from South West Uganda

Aims

We assess the relationship between various hemoglobin variants and some hematological parameters packed cell volume, white blood cells (PCV, WBC) and parasitemia level of patients with malaria in the southwestern, Uganda.

Methods

Patient were enrolled by rapid diagnostic tests (RDTs), confirmed by microscopy, and laboratory outcomes were determined.

Results

Patients positive for malaria RDTs were 155, microscopic-confirmed P. falciparum parasites were 95 (61.29%) having hemoglobin variants HbAA and HbAS; 75 (78.95%) and 13 (13.68%), respectively. The laboratory outcomes showed mean, PCV (32.19 ± 4.83), WBC (5831.66 ± 2888.29) and P. falciparum parasitaemia density (32,605.45 ± 14031), while the hemoglobin variants mean values AA (39,008.85 ± 31,261.56), AC (15908 ± 10173.48), AS (16,561.46 ± 15,380.93), SC (30,524 ± 0.000) and SS(1652 ± 0.000) were significantly different from the total population (34,321.5 ± 21,924.26) parasite-density.

Conclusion

Patients with hemoglobin variants HbAA had a significantly higher parasite-carrying capacity and PCV levels.

Molecular targets for the treatment of AML in the forthcoming 5th World Health Organization Classification of Haematolymphoid Tumours

INTRODUCTION

Acute myeloid leukemia (AML) is a genetically heterogeneous disease for which the treatment armamentarium has been historically restricted to chemotherapy. However, genomic and epigenomic alterations that contribute to AML initiation, maintenance, and relapse have disclosed new insights to the 5th update in WHO Classification of Haematolymphoid Tumours.

AREAS COVERED

After four decades of intensive chemotherapy as a 'one-size-fits-all' concept, several targeted agents have been approved for the treatment of AML. Several compounds, directed against regulators of apoptotic, epigenetic, or micro-environmental pathways, and immune-system modulators, are currently in development and investigation in clinical trials. We review advances in target-based therapy for AML focusing on their mechanism of action, examining the intracellular events and pathways, and the results from published clinical trials.

EXPERT OPINION

To improve patient clinical outcomes, find new biomarkers for therapeutic response, and pinpoint patients who might benefit from novel targeted medicines, next-generation sequencing is being used to evaluate AML-associated mutations. In fact, the new 5th edition of WHO classification has reaffirmed the importance of genetically defined entities that have a prognostic impact, but not all have a specific treatment available. New class of target drugs are in clinical development and could be beneficial to improve the therapeutic armamentarium available.

Hope and Quality of Life among Adolescent with Thalassemia: A Cross-sectional Study in Indonesia

Background: Adolescents with thalassemia major had a worse quality of life (QOL) than healthy adolescents. Hope is considered as a protective factor to enhance QOL. The relationship between hope and quality of life in adolescents has been evaluated in various chronic diseases, across multiple countries, cultures, and settings. However studies on exploring the relationship between hope and QOL among adolescents with thalassemia are limited, especially in Indonesia. Objectives: This study aimed to determine the relationship between hope and QOL among adolescents with thalassemia in Indonesia. Methods: A cross-sectional study was carried out from April to Juni 2021. The respondents in this study were 120 adolescents who met the criteria (1) they were teenagers (10-19 years old) who received regular blood transfusions, (2) they could write and read, (3) adolescents who are not mentally retarded. Instruments include demographic data sheets, Child Hope Scale (CHS), and TranQOL. Data were analysis using the Pearson correlational test and multiple regression hierarchical analysis. Results: This study found that 65 (54.17%) were boys, and 55 (45.83%) were girls. About 64.17% had transfusion period for once in 2 - 4 weeks, and 4.17% with comorbidity, and 77.5% having hemoglobin 7 mg/dl. The mean QOL score among adolescents with thalassemia was 47.82 (SD=15.38). Hope and TranQOL scores were positively and strongly associated (r = 0.463, p<0.01). After adjusting for demographic and clinical factors, this finding revealed that hope was significantly and positively associated with QOL in step two. Hope had a significant impact on thalassemic adolescents' QOL (R2 = 0.371, R2 change = 0.239) Conclusion: Hope is a factor that is related and greatly influences the quality of life of thalassemia survivors so that the development of programs and policies that design the expectations of thalassemia survivors and their families will improve the quality of life of patients with thalassemia.

Current and Future Molecular Targets for Acute Myeloid Leukemia Therapy

OPINION STATEMENT

Acute myeloid leukemia (AML) disease prognosis is poor and there is a high risk of chemo-resistant relapse for both young and old patients. Thus, there is a demand for alternative and target-specific drugs to improve the 5-year survival rate. Current treatment mainstays include chemotherapy, or mutation-specific targeting molecules including FLT3 inhibitors, IDH inhibitors, and monoclonal antibodies. Efforts to devise new, targeted therapy have included recent advances in methods for high-throughput genomic screening and the availability of computer-assisted techniques for the design of novel agents predicted to specifically inhibit mutant molecules involved in leukemogenesis. Crosstalk between the leukemia cells and the bone marrow microenvironment through cell surface molecules, such as the integrins αvβ3 and αvβ5, might influence drug response and AML progression. This review article focuses on current AML treatment options, new AML targeted therapies, the role of integrins in AML progression, and a potential therapeutic agent-integrin αvβ3 antagonist.

Bright Side of Lignin Depolymerization: Toward New Platform Chemicals

Lignin, a major component of lignocellulose, is the largest source of aromatic building blocks on the planet and harbors great potential to serve as starting material for the production of biobased products. Despite the initial challenges associated with the robust and irregular structure of lignin, the valorization of this intriguing aromatic biopolymer has come a long way: recently, many creative strategies emerged that deliver defined products via catalytic or biocatalytic depolymerization in good yields. The purpose of this review is to provide insight into these novel approaches and the potential application of such emerging new structures for the synthesis of biobased polymers or pharmacologically active molecules. Existing strategies for functionalization or defunctionalization of lignin-based compounds are also summarized. Following the whole value chain from raw lignocellulose through depolymerization to application whenever possible, specific lignin-based compounds emerge that could be in the future considered as potential lignin-derived platform chemicals.

Antimalarial and Antiproliferative Cassane Diterpenes of Caesalpinia sappan

Bioassay-guided fractionation of a methanol extract of the seeds of Caesalpinia sappan led to the isolation of 12 new cassane-type diterpenes, caesalsappanins A-L (1-12). Their structures were elucidated on the basis of NMR and HRESIMS analysis, and the absolute configuration of compound 1 was determined by single-crystal X-ray crystallography. All isolated compounds were tested against a chloroquine-resistant Plasmodium falciparum strain for antiplasmodial activities and against a small panel of human cancer cell lines for antiproliferative activities. Compounds 7 and 8 displayed antimalarial activity against the chloroquine-resistant K1 strain of P. falciparum with IC50 values of 0.78 and 0.52 μM and selectivity indices of 17.6 and 16.4, respectively. Compound 10 showed antiproliferative activity against the KB cancer cell line with an IC50 value of 7.4 μM.

Examining the usefulness of a Family Empowerment Program guided by the Illness Beliefs Model for families caring for a child with thalassemia

The purpose of this pilot study was to design, implement, and evaluate a Family Empowerment Program (FEP), guided by the Illness Beliefs Model. Participants included 25 Thai family members who were the primary caregivers of a child with thalassemia. In Phase I, data were collected from participants using individual in-depth interviews and focus groups before involvement in the FEP. In Phase II, 12 hr of FEP sessions were offered to groups of participants. Content analysis of the audiotaped FEP sessions is reported in this article. Family caregivers reported that the FEP helped them share beliefs and experiences related to caring for their child with thalassemia, make decisions related to families' problems/needs and beliefs, provide each other mutual social support, and develop increased ability to manage care for their chronically ill child through sharing information and learning from other family caregivers about family functioning, family management, and family relationships. Future research is needed to examine the FEP intervention under more controlled conditions with measures that include family functioning and child health outcomes.

Clinical course of dengue in patients with thalassaemia

BACKGROUND

Dengue and thalassaemia are prevalent in tropical regions. Thalassaemia patients with dengue present with atypical clinical manifestations and may experience more severe disease and complications.

AIMS

To investigate the clinical manifestations and outcome in thalassaemia patients with dengue.

METHODS

Medical records of thalassaemia patients aged from birth to 18 years with serologically-confirmed dengue who were admitted to Chiang Mai University Hospital, Thailand from January 2005 to December 2010 were reviewed retrospectively. Clinical presentation, laboratory results and outcome were analysed.

RESULTS

Twenty patients were included and their mean (SD) age was 13·6 (3·1) years. Patients were as follows: haemoglobin H (HbH)/Hb Constant Spring disease 7, HbH disease 3, HbH disease/HbE trait one, beta-thalassaemia/HbE disease 7, beta-thalassaemia/HbS disease one and unspecified thalassaemia one. Four patients had primary and the others secondary dengue. Five patients (25%) had severe dengue, three with severe liver involvement, one with a massive upper gastro-intestinal haemorrhage and one with acute interstitial nephritis, raised creatinine and seizures. Nineteen patients required red cells transfusions. All made a full recovery. Almost all patients presented with haemoglobin lower than baseline. While mean (SD) haemoglobin at baseline was 8·2 (1·6) g/dl, mean (SD) haemoglobin on admission was 6·4 (1·6) g/dl. Median maximum AST and ALT levels were 359 (range 42-5344) and 81 (12-1846) units/L, respectively.

CONCLUSIONS

Thalassaemia patients with dengue present with anaemia rather than haemoconcentration. Most patients have markedly increased AST levels in relation to ALT, and severe dengue, especially severe liver involvement, is common. In patients with thalassaemia, awareness of the atypical manifestations should aid early recognition of dengue.

Induction of human fetal hemoglobin via the NRF2 antioxidant response signaling pathway

Although hematopoietic stem cell transplantation and gene therapy have the potential to cure β-thalassemia and sickle cell disease, they are not currently available to most people with these diseases. In the near term, pharmacologic induction of fetal hemoglobin (HbF) may offer the best possibility for safe, effective, and widely available therapy. In an effort to define new pathways for targeted drug development for HbF induction, we evaluated the nuclear factor erythroid 2-related factor 2 (NRF2) antioxidant response element signaling pathway. We found that 3 well-known activators of this pathway increased γ-globin mRNA at nontoxic doses in K562 cells. Tert-butylhydroquinone (tBHQ), the most active of these compounds, increased cellular levels and nuclear translocation of NRF2 and binding of NRF2 to the γ-globin promoter. siRNA knockdown of NRF2 inhibited γ-globin induction by tBHQ. When tested in human primary erythroid cells, tBHQ induced NRF2 binding to the γ-globin promoter, increased γ-globin mRNA and HbF, and suppressed β-globin mRNA and HbA, resulting in a > 3-fold increase in the percentage of HbF. These results suggest that drugs that activate the NRF2/antioxidant response element signaling pathway have the potential to induce therapeutic levels of HbF in people with β-hemoglobinopathies.

Hematopoietic stem cell transplantation for children with thalassemia major in China

Thalassemia is the most common single-gene disorder worldwide that is considered a major public health issue. Hematopoietic stem cell transplantation (HSCT) is the only curative treatment for thalassemia major, the form of the disease reflecting homozygosity for a mutant allele. In China, many patients with thalassemia major cannot financially afford life-long regular supportive care with blood transfusions and iron chelation. Although HSCT is expensive, it is a one-time treatment that is possible in some patients. Disease-free survival rates have been 52-82% after HSCT in China. Graft rejection is the main cause of failure following HSCT. Humoral immune activity may play an important role in engraftment of donor cells. This article reviews the current status of HSCT for children with thalassemia major in China.

Iron delocalisation in the pathogenesis of malarial anaemia

There is consensus that the pathophysiology of malaria-associated anaemia is multifactorial, but the precise mechanisms behind many of the haematological changes during malaria remain unclear. In this review, we attempt to build a composite picture of the pathophysiology of malarial anaemia using evidence from experimental, human and animal studies. We propose that cytokine- and hepcidin-mediated iron delocalisation, a principal mechanism in the anaemia of inflammation, plays an important role in the aetiology of malarial anaemia, and can explain some of the clinical and laboratory findings. These mechanisms interact with other aetiological determinants, such as dietary iron and micronutrient supply, helminth load, other infections and genetic variation, in determining the severity and associated features of anaemia. We suggest that iron delocalisation as a mechanism for malarial anaemia could be exploited for the development of alternative therapeutic strategies for post-malaria anaemia.

Characterization of acute lymphoblastic leukemia subtypes in moroccan children

We present the incidence and the immunologic characteristics of acute lymphoblastic leukemia (ALL) subsets in Moroccan children. We studied 279 unselected patients below the age of 18 years with newly diagnosed ALL. Cases were classified according to immunophenotype: 216 (77.42%) precursor B-cell phenotype (pB-cell), mature B-cell in 4 (1.43%), and T-cell in 59 (21.15%) cases. The subclassification using the CD10 antibody revealed 197 cases pB-ALL CD10+ (91.2%) and 9 cases T-ALL CD10+ (19.2%). The age distribution showed a peak in incidence between 3 and 5 years among the pB-cell ALLs subtype. There was a significantly higher frequency of males in the T-ALL subset (M/F ratio: 2.93 : 1) and more females in the T-ALL CD10+ subset when compared with the T-ALL CD10- subset. All tested pB-cell-lineage ALLs expressed CD19, CD79a, and surface CD22, terminal deoxynucleotidyl transferase (TdT) was detectable in 89.9% of cases, and cells in 74.1% of cases express CD34. All tested T-lineage ALL cells have surface CD7 and cytoplasmic CD3 (cCD3) antigens, CD5 was found in 98.2% cases, and 70.5% express TdT. CD1a, surface CD3 (sCD3), and CD4 are detected in more than 80% of cases; this frequency is higher than the 45% generally observed. Myeloid antigens occur more frequently and were expressed in 124 (57.4%) of pB-cell-ALL cases and 20 (33.9%) of T-cell ALL cases. Our results show that the distribution of ALLs in Moroccan children is similar with the general distribution pattern in developed countries except for the high frequency of T-ALL phenotype. The phenotypic profiles of our patients are close to those reported in literature for B-lineage ALLs; for the T-cell ALL subgroup, the blast cells express more CD1a, surface CD3, and CD4 while expressing less TdT. The high frequency of CD1a expression resulted in an excess of the common thymocyte subtype.

UK-based real-time lymphoproliferative disorder diagnostic service to improve the management of patients in Ghana

The objective of the study was to evaluate the feasibility of a UK-based real-time service to improve the diagnosis and management of lymphoproliferative disorders (LPDs) in Ghana. Adult patients reporting to hospital with a suspected LPD, during a 1 year period, were prospectively enrolled. Bone marrow and/or lymph node biopsies were posted to the Haematology Malignancy Diagnostic Service (HMDS), Leeds, UK and underwent morphological analysis and immunophenotyping. Results were returned by e-mail. The initial diagnoses made in Ghana were compared with the final HMDS diagnoses to assess the contribution of the HMDS diagnosis to management decisions. The study was conducted at the two teaching hospitals in Ghana—Komfo Anokye, Kumasi and Korle Bu, Accra. Participants comprised 150 adult patients (≥12 years old), 79 women, median age 46 years. Bone marrow and lymph node biopsy samples from all adults presenting with features suggestive of a LPD, at the two teaching hospitals in Ghana, over 1 year were posted to a UK LPD diagnostic centre, where immunophenotyping was performed by immunohistochemistry. Molecular analysis was performed where indicated. Diagnostic classifications were made according to international criteria. Final diagnosis was compared to the initial Ghanaian diagnosis to evaluate discrepancies; implications for alterations in treatment decisions were evaluated. Median time between taking samples and receiving e-mail results in Ghana was 15 days. Concordance between initial and final diagnoses was 32% (48 of 150). The HMDS diagnosis would have changed management in 31% (46 of 150) of patients. It is feasible to provide a UK-based service for LPD diagnosis in Africa using postal services and e-mail. This study confirmed findings from wealthy countries that a specialised haematopathology service can improve LPD diagnosis. This model of Ghana–UK collaboration provides a platform on which to build local capacity to operate an international quality diagnostic service for LPDs.

Acute Wilson disease associated with E beta-thalassemia

We report on an 11-year-old girl with concomitant Ebeta thalassemia (EbetaT) and Wilson disease (WD). She was diagnosed with EbetaT at 2 years of age, but the coexistence of WD could only be established at 11 years. The diagnosis of the later was based on the clinical presentation of hepatitis and severe Coomb's negative hemolytic anemia, coupled with laboratory evidence of WD. To our knowledge, this is the first report on the cooccurrence of EbetaT and WD. As both the conditions are associated with variable degrees of hemolysis, WD in the setting of EbetaT may remain masked and consequently remain undiagnosed for a long time. Sudden, severe hemolysis in a patient of thalassemia may be explained by the coexistence of additional pathology, in this case WD.

Trends in childhood leukemia mortality in Brazil and correlation with social inequalities

BACKGROUND

Mortality from childhood leukemia has declined substantially in developed countries but less markedly in the developing world. This study was designed to describe mortality trends in childhood leukemia and the impact of social inequalities on these trends in Brazil from 1980 to 2002.

METHODS

Cancer mortality data by cause and estimates of resident population stratified by age and sex were obtained from the Brazilian Mortality Information System (SIM) for the years 1980 to 2002. Age-standardized (ages 0-19 years) mortality rates were calculated by the direct method using the 1960 world standard population. Trends were modeled using linear regression with 3-year moving average rates as the dependent variable and with the midpoint of the calendar year interval (1991) as the independent variable. The Index of Social Exclusion was used to classify the 27 Brazilian states. Pearson correlation was used to describe the correlation between social exclusion and variations in mortality in each state.

RESULTS

Age-standardized mortality rates for boys decreased from 2.05 per 100,000 habitants in 1984 to 1.44 100,000 habitants in 1995, whereas the observed corresponding decline among girls was from 1.60 per 100,000 habitants in 1986 to 1.14 per 100,000 habitants in 1995. Statistically significant declining trends in mortality rates were observed for boys (adjusted correlation coefficient [r(2)] = 0.68; P < .001) and girls (adjusted r(2) = 0.62; P < .001). Significant negative correlations between social inequality and changes in mortality were noted for boys (r = -0.66; P = .001) and for girls (r = -0.78; P < .001).

CONCLUSIONS

A consistent decrease in mortality rates from childhood leukemia was noted in Brazil. Higher decreases in mortality were observed in more developed states, possibly reflecting better health care.

Pattern of haematological diseases diagnosed by bone marrow examination in Yemen: a developing country experience

There is lack of information about the relative prevalence of haematological disorders in Yemen and other Middle East countries. The aim of this study was to evaluate the pattern of haematological diseases diagnosed by bone marrow examination in Yemen considering the limited diagnostic facilities. At the referral haematology centre in Yemen, between November 1999 and November 2005, 785 patients >14 years old were evaluated by bone marrow examination. Relevant investigations were performed when needed. A total of 627 patients had haematological disorders other than lymphoma, and their data were analysed. There were 273 females and 354 males. A total of 159 patients had Acute myeloid leukaemia, 75 had acute lymphocytic leukaemia, 87 had chronic myeloid leukaemia, 36 chronic lymphocytic leukaemia, eight had multiple myeloma, 13 myelodysplastic syndromes, seven myelofibrosis, seven polycythaemia vera, three primary thrombocythaemia, two hairy cell leukaemia, two metastases, 36 aplastic anaemia, 29 immune thrombocytopenic purpura (ITP), nine autoimmune haemolytic anaemia, three pernicious anaemia, 65 iron deficiency anaemia, 57 megaloblastic anaemia and malaria, 18 mixed deficiencies, and 11 patients had visceral leishmaniasis. Sex- and age-related distribution of the various disorders was also presented. In conclusion, the leukaemias were the most frequently encountered diagnosis followed by iron deficiency anaemia, megaloblastic anaemia and malaria, aplastic anaemia and ITP respectively. The other haematological disorders were less common. These findings are comparable with that seen in other developing and developed countries.

Inherited hemoglobin disorders in Guinea-Bissau, West Africa: a population study

The determination of the prevalence of inherited hemoglobin (Hb) disorders in endemic areas is important in order to develop programs for their control and management. The aim of this study is to determine the prevalence of inherited Hb diseases in Guinea-Bissau which is situated on the west coast of Africa, between Senegal and Guinea. One thousand and fifty-seven blood samples were collected and analyzed with high performance liquid chromatography (HPLC) for detection of beta-thalassemia (thal) and Hb variants, and by gap polymerase chain reaction (gap-PCR) for the detection of deletions in the alpha-globin genes. We found 4.7% children were heterozygous for Hb S [beta6(A3)Glu-->Val, GAG -->GTG], 0.2% were homozygous for Hb S, and 0.3% were heterozygous for Hb C [beta6(A3)Glu-->Lys, GAG -->AAG]. One child had heterozygous beta+-thal, 13.8% were heterozygous for the -alpha3.7 deletion, 1.5% were homozygous for the -alpha3.7 deletion, and 1.5% were heterozygous for the -alpha4.2 deletion. We recommend national screening programs to focus primarily on sickle cell disease, since beta-thal is rare, and the observed alpha-thal deletions are of minor genetic importance.

Factors contributing to the development of anaemia in Plasmodium falciparum malaria: what about drug-resistant parasites?

A major manifestation of complicated malaria especially among children is severe anaemia, the pathogenesis of which is not well understood. Among other factors, suppression of the bone marrow's response to erythropoietin, which is rapidly reversed after successful treatment of the malaria, has been implicated in its pathogenesis. Since resolution of malaria restores erythropoiesis, we hypothesized that drug-resistant strains of Plasmodium falciparum would increase the risk of severe anaemia developing from initially uncomplicated malaria. Using both in vivo and in vitro drug-sensitivity tests we compared the prevalence of drug-resistant malaria between severe malarial anaemia SA and non-anaemic malaria NAM patients. Assessment of treatment outcome using the WHO in vivo criteria showed no significant difference in parasite resistance between the two groups. The mean parasite clearance time was also comparable. Treatment failures of about 14 per cent and 12 per cent were observed between SA and NAM patients respectively. The in vitro drug susceptibility test showed overall mean IC50 values of 0.41x10(-6) mol/l and 0.32x10(-6) mol/l blood for SA and NAM groups respectively. Geometric mean pre-treatment blood levels of chloroquine did not differ much between the two groups. Findings from this study could not therefore implicate drug-resistant parasites in the pathogenesis of severe malarial anaemia.

Clinical and epidemiological analyses of human pythiosis in Thailand

BACKGROUND

Pythiosis is an emerging and life-threatening infectious disease in humans and animals that is caused by the pathogenic oomycete Pythium insidiosum. Human pythiosis is found mostly in Thailand, although disease in animals has been increasingly reported worldwide. Clinical information on human pythiosis is limited, and health care professionals are unfamiliar with the disease, leading to underdiagnosis, delayed treatment, and poor prognosis.

METHODS

To retrospectively study the clinical and epidemiological features of human pythiosis, we analyzed clinical data from patients with pythiosis diagnosed during the period of January 1985 through June 2003 at 9 tertiary care hospitals throughout Thailand.

RESULTS

A total of 102 cases of human pythiosis were documented nationwide. A substantial proportion (40%) of cases occurred in the last 4 years of the 18-year study interval. Clinical presentations fell into 4 groups: cutaneous/subcutaneous cases (5% of cases), vascular cases (59%), ocular cases (33%), and disseminated cases (3%). Almost all patients with cutaneous/subcutaneous, vascular, and disseminated pythiosis (85%) had underlying thalassemia-hemoglobinopathy syndrome. Most ocular cases (84%) were associated with no underlying disease. A majority of the patients were male (71%), were aged 20-60 years (86%), and reported an agricultural occupation (75%). Regarding treatment outcomes, all patients with disseminated infection died; 78% of patients with vascular disease required limb amputation, and 40% of these patients died; and 79% of patients with ocular pythiosis required enucleation/evisceration.

CONCLUSIONS

Here, we report, to our knowledge, the largest case study of human pythiosis. The disease has high rates of morbidity and mortality. Early diagnosis and effective treatment are urgently needed to improve clinical outcomes. Because P. insidiosum is distributed worldwide and can infect healthy individuals, an awareness of human pythiosis should be promoted in Thailand and in other countries.

Chicken Egg Yolk Antibodies Specific for the γ Chain of Human Hemoglobin for Diagnosis of Thalassemia

Immunoglobulin Y (IgY) technology was used to generate anti-hemoglobin Bart's (Hb Bart's) IgY antibodies (Abs) for development into an enzyme-linked immunosorbent assay (ELISA) test for thalassemia diagnosis. Hb Bart's purified from the hemolysate of a patient with Hb Bart's hydrops fetalis (homozygous alpha-thalassemia) was used to immunize a chicken via the pectoralis muscle. After water dilution and sodium sulfate precipitation, 40 to 70 mg of IgY could be extracted from an egg. IgY, first detected in sera 2 weeks after immunization, reached the highest titer at week 4, and the titer remained stable for at least 2 weeks before declining. The pattern of Ab response in the yolk was the same as in the serum but was somewhat delayed. The IgY Abs produced reacted with gamma globin, Hb Bart's, Hb F, normal cord hemolysate (Hbs F plus A), and Hb Bart's hydrops fetalis (Hbs Bart's plus Portland) and to a lesser degree with beta globin, Hb A, Hb A2 and adult hemolysate (Hbs A plus A2), but the Abs did not react with alpha globin. Immunoaffinity purification with Hb A coupled to Sepharose was used to isolate an unbound IgY that reacted with Hb F, Hb Bart's, and gamma globin, and this IgY was used to develop an ELISA test for thalassemia diagnosis. The results of direct ELISA analyses of 336 hemolysate samples from individuals with various known thalassemia genotypes and phenotypes and from healthy individuals confirmed the specificity of the polyclonal Abs for Hbs containing Hb F and Hb Bart's. This specificity, which was due to the Abs' strong reactivity in cases of pathologic thalassemic diseases and weak reactivity in cases of nonpathologic thalassemic diseases, depended on the levels of Hb Bart's and Hb F.

Antimalarial compounds from Grewia bilamellata

Bioassay-directed fractionation led to the isolation of 12 compounds from a sample of the dried leaves, twigs, and stems of Grewia bilamellata. Five of the isolates, 3alpha,20-lupandiol (1), grewin (2), nitidanin (4), 2alpha,3beta-dihydroxy-olean-12-en-28-oic acid (5), and 2,6-dimethoxy-1-acetonylquinol (6), showed varying degrees of in vitro antimalarial activity against Plasmodium falciparum, but were devoid of significant cytotoxicity to the human oral epidermoid KB cancer cell line. Of the 12 isolates, compounds 1, 2, and 3 (bilagrewin) were determined to be a new triterpene, a new coumarinolignan, and a new neolignan, respectively. Other known compounds isolated in this study were 8-O-4' neolignan guaiacylglycerol-beta-coniferyl ether isomers (threo and erythro), cleomiscosin D, icariol A(2), ciwujiatone, and daucosterol. The structures of 1-3 were elucidated and identified on the basis of spectroscopic data including 1D and 2D NMR analysis.

Mutations of the FLT3 gene in adult acute myeloid leukemia: determination of incidence and identification of a novel mutation in a Thai population

FLT3 mutations have been reported to be the most frequent mutation in acute myeloid leukemia (AML). No data currently exist regarding FLT3 mutations in Southeast Asian patients. In this study, the incidence and type of FLT3 mutation in a large series of Thai AML patients were determined. FLT3 internal tandem duplication (ITD) mutations were observed in 24.6%, FLT3 tyrosine kinase domain mutations in 3.1%, and dual mutations in 2.7% of 256 newly diagnosed Thai AML patients. ITD mutations were mostly restricted to the juxtamembrane domain, and the in-frame ITD length varied from 21 to 201 base pairs. Six types of point mutations were identified, including Asp835Tyr, Asp835His, Asp835Glu, Asp835Ala, Ile836, and a novel mutation, Asp835Del/Ile836Val, which resulted in the loss of aspartic acid and substitution of isoleucine by valine. A rare leukemia karyotype, trisomy 11, was found to coexist with this novel FLT3 mutation, whereas the majority of patients with FLT3 mutations had a normal karyotype. Overall, FLT3 mutation was associated with a significantly higher white blood cell count and older age than the wild-type FLT3. In conclusion, the incidence of FLT3 mutation in Thailand is as high as that of western countries. The clinical significance of the novel mutation requires further studies in a larger population.

Cyclosporine monotherapy for severe aplastic anemia: a developing country experience

BACKGROUND

Immunosuppression is the most effective treatment for aplastic anemia after hematopoietic stem cell transplantation. Although the combination of cyclosporine and antithymocyte globulin (ATG) is superior to either agent alone, cyclosporine monotherapy is an easily available, safe and cheap immunosuppressive therapy (IST) option. These advantages are particularly valuable in developing countries where ATG is frequently not available.

PATIENTS AND METHODS

In the referral hematology center in Yemen, 20 patients (16 males and 4 females) with severe aplastic anemia (SAA) were prospectively identified and managed with cyclosporine monotherapy during the period between April 2001 and November 2004.

RESULTS

Data from 14 patients who received cyclosporine for at least 3 months were analyzed. At 6 months, 2 (14.3%) patients achieved complete remission (CR) and 5 (35.7%) patients achieved partial remission (PR) and at 1 year, 4 (28.6%) patients achieved CR and 3 (21.4%) patients remained in PR. The overall response rate was 50% and the cumulative survival rate at 1 year was 78.6%. The median time to remission was 120 days (range, 46 to 131 days). Side effects were modest and easily monitored.

CONCLUSION

Our results support findings that cyclosporine monotherapy is an effective and safe immunosuppressive therapy for SAA, and that it could be a reasonable IST option for patients in developing countries.

In utero gene therapy: current challenges and perspectives

Over the past few years, considerable progress in prenatal diagnosis and surgery combined with improvements in vector design vindicate a reappraisal of the feasibility of in utero gene therapy for serious monogenetic diseases. As adult gene therapy gathers pace, several apparent obstacles to its application as a treatment may be overcome by pre- or early postnatal treatment. This review will examine the concepts and practice of prenatal vector administration. We aim to highlight the advantages of early therapeutic intervention focusing on diseases that could benefit greatly from a prenatal gene therapy approach. We will pay special attention to the strategies and vectors that are most likely to be used for this application and will speculate on their expected developments for the near future.

Cardiac iron determines cardiac T2*, T2, and T1 in the gerbil model of iron cardiomyopathy

BACKGROUND

Transfusional therapy for thalassemia major and sickle cell disease can lead to iron deposition and damage to the heart, liver, and endocrine organs. Iron causes the MRI parameters T1, T2, and T2* to shorten in these organs, which creates a potential mechanism for iron quantification. However, because of the danger and variability of cardiac biopsy, tissue validation of cardiac iron estimates by MRI has not been performed. In this study, we demonstrate that iron produces similar T1, T2, and T2* changes in the heart and liver using a gerbil iron-overload model.

METHODS AND RESULTS

Twelve gerbils underwent iron dextran loading (200 mg . kg(-1) . wk(-1)) from 2 to 14 weeks; 5 age-matched controls were studied as well. Animals had in vivo assessment of cardiac T2* and hepatic T2 and T2* and postmortem assessment of cardiac and hepatic T1 and T2. Relaxation measurements were performed in a clinical 1.5-T magnet and a 60-MHz nuclear magnetic resonance relaxometer. Cardiac and liver iron concentrations rose linearly with administered dose. Cardiac 1/T2*, 1/T2, and 1/T1 rose linearly with cardiac iron concentration. Liver 1/T2*, 1/T2, and 1/T1 also rose linearly, proportional to hepatic iron concentration. Liver and heart calibrations were similar on a dry-weight basis.

CONCLUSIONS

MRI measurements of cardiac T2 and T2* can be used to quantify cardiac iron. The similarity of liver and cardiac iron calibration curves in the gerbil suggests that extrapolation of human liver calibration curves to heart may be a rational approximation in humans.

Clinical epidemiology of childhood cancer in Central America and Caribbean countries

BACKGROUND

Countries with scarce resources have the right to appropriate essential health care but very few reports discuss how this can be achieved. We assessed the survival of a large cohort of pediatric oncological patients to provide hard data on which to base realistic evaluation and planning schemes.

PATIENTS AND METHODS

This multicenter retrospective survey covered consecutively diagnosed and treated patients admitted to eight national level hospitals in seven countries in Central America and the Caribbean. The research protocol was discussed extensively, so the data to be collected and the criteria for their evaluation were clearly pre-defined. We analysed 2214 patients diagnosed between 1996 and 1999 with various cancers, classified as hemato-oncological disorders (70%) and solid tumors (30%).

RESULTS

Three-year overall survival was 48.4% [standard error (SE) 1.3]. Detailed analysis of acute lymphoblastic leukemia highlighted the wide intercountry variability: 3-year survival was 62.2% (SE 5.3) in Cuba, 74.2% (SE 3.3) in Costa Rica, 61.7% (SE 4.9) in Nicaragua, and lower in the other four countries.

CONCLUSIONS

The yield of diagnostic-therapeutic protocols depends largely on the context of care in which they are applied. This paper documents the importance of including epidemiological research in interventions for cooperation in complex health areas such as pediatric oncology.

International Collaboration on Childhood Leukemia

The current cure rate of childhood acute lymphoblastic leukemia has reached 80% in many industrialized countries, but in developing countries the rate is often less than 10%. To advance the cure rate, investigators have formed several parallel initiatives in both industrialized and developing countries through international collaboration and partnership. Among industrialized countries, investigators have combined data to conduct in-depth studies of the biology and heterogeneity of high-risk or drug-resistant subgroups of leukemia to identify optimal or novel treatments. Alliances have been established among government, local nongovernmental organizations, health care providers, and international groups to improve the survival rate of childhood leukemia in developing countries. "Twinning" partnerships between a well-established individual institution or study group and a pediatric cancer unit in a developing country has proved to be the most successful strategy to date.