Assessment of P-gp and MRP1 activities using MultiDrugQuant Assay Kit: a preliminary study of correlation between protein expressions and its functional activities in newly diagnosed acute leukaemia patients

Multidrug resistance (MDR) is believed to be responsible for poor response of patients towards chemotherapy particularly patients with acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL). The best-characterized resistance mechanism is the one mediated by permeability-glycoprotein (P-gp) encoded by MDR1 gene, which is responsible for drug efflux. We studied P-gp and multidrug resistance-associated protein 1 (MRP1) expression and functional activities in 43 newly diagnosed acute leukemia cases (19 paediatric ALL cases and 24 adult AML cases). The expression and functional activities were examined using flow cytometry and MultiDrugQuant assay kit (involving calcein AM uptake and efflux). P-gp and MRP1 expression and its functional activities were observed in 68.4% of paediatric ALL. In adult AML cases, all cases expressed MRP1 and its functional activities but only 58.3% were positive for P-gp and its functional activities. We were able to show a significant correlation between the expression of the multidrug resistant protein (P-gp and MRP1) and their functional activity in adult AML and paediatric ALL samples.

Growth velocity in transfusion dependent prepubertal thalassemia patients: results from a thalassemia center in Malaysia

Growth impairment is commonly seen in children with thalassemia despite regular blood transfusions and desferrioxamine treatments. We investigated the growth velocity of 26 prepubertal patients with beta-thalassemia or HbE-beta thalassemia who were transfusion dependent aged between 2 and 13 years. The prevalence of impaired growth velocity (ie, growth velocity less than the third percentile) amongst the transfusion dependent prepubertal thalassemics was 57.7% compared to 19.2% in the control group. The mean height velocity of the thalassemics was 11.1% less than controls but this difference was not statistically significant (4.23cm/year vs 4.76cm/year, p = 0.08). The mean serum ferritin level of the thalassemics with a height < 3rd percentile was higher compared to those with a height > 3rd percentile (4,567.0 vs 2,271.0, p = 0.01). Our study showed that there was a high prevalence of impaired growth velocity amongst our transfusion dependent prepubertal thalassemics. This highlights the problem of inadequate chelation therapy, and compliance with chelation therapy amongst our patients. This study emphasizes the importance of monitoring growth parameters and optimal iron chelation therapy in these patients.

Piperacillin-tazobactam plus amikacin as an initial empirical therapy of febrile neutropenia in paediatric cancer patients

INTRODUCTION

We evaluated piperacillin-tazobactam in association with amikacin in the initial empirical therapy of febrile neutropenic children.

METHODS

An open-labelled, non-randomised, prospective trial to assess the efficacy and safety of this association was conducted from June 1, 2001 to December 31, 2002. Children and adolescents were treated for a haematological malignancy or a primary, refractory or relapsed solid tumour, and presented with febrile neutropenia. Patients received intravenous piperacillin-tazobactam (90 mg/kg/dose every eight hours) plus a single daily dose of amikacin at 15 mg/kg/day, maximum 250 mg. If fever persisted, second-line therapy with carbapenem was administered. Teicoplanin was added for gram-positive isolates or for unremitting fever after 48 hours, if clinically indicated. Amphotericin B was added at 96 hours, if fever and neutropenia persisted.

RESULTS

155 episodes of fever and neutropenia in 76 patients were evaluable. 40 (25.8 percent) episodes were a microbiologically-documented infection, 30 (19.4 percent) were clinically-documented, and 85 (54.8 percent) were unexplained fever. 77 (49.7 percent) episodes responded to piperacillin-tazobactam plus amikacin without a need for treatment modification. A higher success rate (63.5 percent) was observed in episodes with unexplained fever. The predominant pathogens isolated in our study were gram-negative organisms (70.7 percent). A mild gastrointestinal intolerance occurred in 35 out of 155 (22.6 percent) episodes.

CONCLUSION

This study suggests that piperacillin-tazobactam plus amikacin presents a satisfactory efficacy and a good tolerance as initial empirical therapy for febrile neutropenic children.

Malignant pancreatic carcinoid tumour

Pancreatic carcinoid tumours are rare, particularly within the paediatric population. The clinical presentation is largely dependent on the functionality of the tumour. Although the tumour is generally slow-growing, surgical resection is still the mainstay of curative treatment. Morbidity is, however, significantly contributed by secretion of excess hormones; in view of this, biotherapy is an important treatment strategy. Octreotide, a somatostatin analogue, has been shown to be successful in both symptomatic control and stability of tumour progression. We report a 12-year-old girl, who presented with hypertensive crisis, and showed good response to a combination of chemotherapy and octreotide.

Transient abnormal myelopoeisis in newborns with Down syndrome

Transient abnormal myelopoeisis (TAM) is a haematological phenomenon commonly seen in newborns with Down syndrome. Although the majority show spontaneous resolution, this condition should not be dismissed too readily as there have been associated fatalities. Furthermore, even for those who do show spontaneous resolution, a significant percentage will develop acute megakaryoblastic leukaemia within the next few years of life. We report a series of four patients with TAM who presented with hepatosplenomegaly and leucocytosis detected on preliminary investigations.

Cefepime plus amikacin as an initial empirical therapy of febrile neutropenia in paediatric cancer patients

INTRODUCTION

We evaluated the efficacy of cefepime in association with amikacin in the initial empirical therapy of febrile neutropenic children.

METHODS

The study was an open-labelled, non-randomised prospective trial to assess the efficacy and safety of this association, from January 2003 to December 2003. Children and adolescents were treated for a haematological malignancy or a primary, refractory or relapsed solid tumour, and presented with febrile neutropenia. Patients received cefepime (50 mg per kg per dose every 8 hours for children weighing less than or equal to 40 kg; and 2 g every 8 hours for those weighing more than 40 kg) plus a single daily dose of amikacin at 15 mg per kg per day, up to a maximum 250 mg. If fever persisted, a second-line therapy with carbapenem was administered. Amphotericin B was added at 96 hours if fever and neutropenia persisted.

RESULTS

103 episodes of fever and neutropenia were evaluated in 54 patients. 18.4 percent of the episodes were microbiologically-documented infections, 24.3 percent were clinically documented, and 57.3 percent were episodes with unexplained fever. 54.4 percent of the episodes responded to cefepime plus amikacin without a need for treatment modification. A higher success rate (74.6 percent) was observed in episodes with unexplained fever. In all cases of persistent fever, the antibiotics were changed to carbapenem within 72 hours and all patients survived. One patient died because of culture-negative septic shock within 24 hours of admission. A mild gastrointestinal intolerance occurred in three patients.

CONCLUSION

This study suggests that cefepime plus amikacin presents a satisfactory efficacy and a good tolerance as an initial empirical therapy for febrile neutropenic children.

Recurrent gastric inflammatory myofibroblastic tumour in a 13-year-old male

A 13-year-old boy who had epigastric pain and pallor for 2 months and found to have an ulcerative mass in the stomach and underwent partial gastrectomy. A diagnosis of inflammatory myofibroblastic tumour (IMT) of the stomach was made on histological examination. Three years later, recurrence in the stomach, with invasion into the pancreas and hilum of the spleen was noted and was managed by wide wedge resection of the stomach, distal pancreatectomy and splenectomy. The patient has been recurrence-free for the past 2 years. Gastric IMT is an uncommon tumour in children with unpredictable prognosis.

Use of the denaturing gradient gel electrophoresis (DGGE) method for mutational screening of patients with familial hypercholesterolaemia (FH) and Familial defective apolipoprotein B100 (FDB)

Familial hypercholesterolaemia (FH) and Familial defective apolipoprotein B100 (FDB) are autosomal dominant inherited diseases of lipid metabolism caused by mutations in the low density lipoprotein (LDL) receptor and apolipoprotein B 100 genes. FH is clinically characterised by elevated concentrations of total cholesterol (TC) and low density lipoprotein cholesterol (LDL-C), presence of xanthomata and premature atherosclerosis. Both conditions are associated with coronary artery disease but may be clinically indistinguishable. Seventy-two (72) FH patients were diagnosed based on the Simon Broome's criteria. Mutational screening was performed by polymerase chain reaction (PCR)-denaturing gradient gel electrophoresis (DGGE). Positive mutations were subjected to DNA sequencing for confirmation of the mutation. We successfully amplified all exons in the LDL receptor and apo B100 genes. DGGE was performed in all exons of the LDL receptor (except for exons 4-3', 18 and promoter region) and apo B100 genes. We have identified four different mutations in the LDL receptor gene but no mutation was detected in the apo B 100 gene. The apo B100 gene mutation was not detected on DGGE screening as sequencing was not performed for negative cases on DGGE technique. To our knowledge, the C234S mutation (exon 5) is a novel mutation worldwide. The D69N mutation (exon 3) has been reported locally while the R385W (exon 9) and R716G (exon 15) mutations have not been reported locally. However, only 4 mutations have been identified among 14/72 patients (19.4%) in 39 FH families. Specificity (1-false positive) of this technique was 44.7% based on the fact that 42/76 (55.3%) samples with band shifts showed normal DNA sequencing results. A more sensitive method needs to be addressed in future studies in order to fully characterise the LDLR and apo B100 genes such as denaturing high performance liquid chromatography. In conclusion, we have developed the DNA analysis for FH patients using PCR-DGGE technique. DNA analysis plays an important role to characterise the type of mutations and forms an adjunct to clinical diagnosis.

Peginterferon alfa-2b and ribavirin in thalassaemia/chronic hepatitis C virus-co-infected non-responder to standard interferon-based

We describe a patient with HbE-beta thalassaemia and chronic hepatitis C virus infection (genotype 1a) who was treated successfully with peginterferon alfa-2b and ribavirin, following failure to respond to standard interferon and ribavirin therapy. She had sustained virological response for nearly 24 months after completing peginterferon alfa-2b and ribavirin therapy. Transfusion requirements were significantly increased during combination therapy due to ribavirin-induced haemolysis. The adverse effects of interferon were well tolerated. Combination therapy with peginterferon alfa-2b and ribavirin maybe a feasible treatment option for a subset of thalassaemia/HCV infected non-responders to standard interferon-based therapy.

Research on cancer diagnosis in Malaysia: current status

Cancer is a major morbidity and mortality concern in Malaysia. Based on National Cancer Registry data, the Malaysian population is estimated to bear a cancer burden of about 40,000 new cases per year, and a cumulative lifetime risk of about 1:4. Cancer research in Malaysia has to consider needs relevant to our population, and resources constraints. Hence, funding bodies prioritise cancers of high prevalence, unique to our community and posing specific clinical problems. Cancer diagnosis is crucial to cancer management. While cancer diagnosis research largely aims at improvements in diagnostic information towards more appropriate therapy, it also impacts upon policy development and other areas of cancer management. The scope of cancer diagnosis upon which this paper is based, and their possible impact on other R&D areas, has been broadly categorized into: (1) identification of aetiological agents and their linkages to the development of precancer and cancer (impact on policy development, cancer prevention and treatment), (2) cancer biology and pathogenesis (impact on cancer prevention, treatment strategies and product development), (3) improvements in accuracy, sensitivity and specificity in cancer detection, monitoring and classification (impact on technology development) and (4) prognostic and predictive parameters (impact on treatment strategies). This paper is based on data collected by the Working Group on Cancer Diagnosis Research for the First National Conference on Cancer Research Coordination in April 2004. Data was collated from the databases of Institutions/Universities where the authors are employed, the Ministry of Science, Technology and Innovation (MOSTI) and targeted survey feedback from key cancer researchers. Under the 7th Malaysia Plan, 76 cancer projects were funded through the Intensified Research in Priority Areas (IRPA) scheme of MOSTI, amounting to almost RM15 million of grant money. 47(61.8%) of these projects were substantially in cancer diagnosis, accounting for 65.6% (RM 9.7 million) of cancer project funds. The 8th Malaysia Plan saw a change in research strategy. The IRPA agency fielded several top-down projects which encouraged a multicentre and multidisciplinary approach. This resulted in larger funding per project i.e. RM32 million for 49 projects. There was also a surge of interest in drug development and natural products. Because of this shift in direction, cancer diagnosis projects constituted only 51% of IRPA-funded cancer projects. Nonetheless funding for cancer diagnosis research has exceeded that of the 7th Malaysia Plan, being RM12.5 million by March 2004. The majority of such research is carried out at the Universities, engaging a large number of young scientists and postgraduate students (51 MSc and 21 PhD). A lot of research findings presented at scientific meetings have not yet been published and there is a glaring shortage of patents and commercialization of research findings (such as creation of test kits). Because diagnosis is very much a part of clinical practice, many researchers felt satisfied and confident that their work will be translated into practice and will significantly improve diagnostic services in Malaysia. National guidelines and consensus development on at least three malignancies i.e. breast cancer, oral cancer and lymphoma, have substantial basis in local R&D work. Problems encountered in research included (1) insufficient funding to realize research objectives, (2) lack of local expertise (most research assistants are inexperienced BSc graduates with no or minimal research experience), (3) inadequate technical support from vendors during equipment failure, (4) inexperienced Institutional development units to assist in product development, (5) lack of venture capital for commercialization of findings, and (6) inadequate incentives to undertake research. Researchers pointed out that plans to promote research should include the establishment of (1) regional and national cancer tissue banks, (2) a National Cancer Research Institute, (3) a dedicated cancer research fund, (4) a registry of cancer researchers, (5) national research coordinators, (6) improved coverage by the National Cancer Registry, (7) more international collaboration, (8) a better career structure for researchers, (9) improved Institutional support for product realization, and (10) better recognition for cancer researchers.

Prolonged remission after splenectomy for refractory Evans syndrome--a case report and literature review

We describe a patient with Evans syndrome (autoimmune hemolytic anemia and autoimmune thrombocytopenia) who was refractory to steroids and intravenous immunoglobulin. She responded to splenectomy and has remained in clinical remission for 3 years. In the majority of cases, splenectomy rarely induces a durable remission but it may be beneficial in a small group of patients, hence should be considered as alternative therapy in the management of these patients.

Case report post-splenectomy sepsis in thalassemic patients

Thalassemia is the commonest hemoglobinopathy in Malaysia. Patients with thalassemia major are transfusion dependent, and a large proportion of them will require splenectomy. As this particular group of patients is immunocompromized, overwhelming sepsis is a recognized complication. We report a series of three patients who all developed intra-abdominal abscesses following splenectomy.

Abnormalities in lung function among multiply-transfused thalassemia patients: results from a thalassemia center in Malaysia

The aim of this study was to: (1) determine the prevalence and patterns of lung dysfunction among transfusion dependent thalassemics; (2) determine the associated factors that might contribute to this problem. This was a cross-sectional study involving 66 patients with transfusion dependent thalassemia aged 10 years and above. All patients underwent physical examination, standardized pulmonary function tests including spirometry, lung volume, and the carbon monoxide diffusion capacity. A restrictive pattern of lung dysfunction was observed in 22 patients (33.3%) and none showed the presence of obstructive ventilatory impairment. A reduction in the carbon monoxide diffusion capacity (DLCO) was seen 87.9% of the patients, including 7.6% who had evidence of hypoxemia. Ten patients showed a reduction in the FEF25-75% although they did not fulfil the criteria for small airway disease. No correlation was found between lung dysfunction and serum ferritin levels in the patients. Restrictive lung dysfunction and diffusion impairment were the predominant abnormalities found in our cohort of patients.

Congenital factor VII deficiency: a case report

Factor VII deficiency is a rare congenital blood disorder. Its clinical features are rather variable and ranges from epistaxis to massive intracranial haemorrhage. Treatment involves replacement therapy, which constitutes use of fresh frozen plasma, prothrombin complex concentrates or recombinant activated factor VII. Although it is a rare entity, one still needs to consider it as a probable diagnosis in a newborn with coagulopathy. We report here a case of Factor VII deficiency in a newborn who presented with subdural haemorrhage at day 4 of life.

CD44s expression correlated with the International Neuroblastoma Pathology Classification (Shimada system) for neuroblastic tumours

AIM

CD44 is a cell adhesion molecule that plays an important role in the cascade of metastasis and progression of human malignant tumours. A large family of variants or isoforms, generated by alternative splicing of a single gene, has been reported to be involved in the malignant process by conferring metastatic potential to non-metastatic cells. The objective of this study was to compare the expression of CD44 standard molecule with the International Neuroblastoma Pathology Classification (INPC) for neuroblastic tumours, a histological grading system based on the Shimada system for predicting the clinical outcome in neuroblastic tumours.

METHODS

Paraffin blocks of primary neuroblastic tumour were graded according to the INPC system into favourable and unfavourable histological types. Tumour tissues were then analysed with immunostaining using monoclonal antibodies against the CD44 epitope.

RESULTS

In this retrospective study, 32 cases of primary neuroblastic tumour were collected. Based on the INPC system, 13 cases (40.6%) had a favourable histology while 19 cases (59.4%) were of unfavourable histology. CD44 standard (CD44s) expression was detected in 69.2% of neuroblastic tumours with favourable histological type while 89.5% of tumours with unfavourable histological type did not express CD44s staining. Statistically, there was significant correlation between morphological grading of neuroblastic tumours based on the INPC and the presence of CD44 staining (Fisher's exact test, P<0.05).

CONCLUSION

This study shows that there is a significant correlation between CD44s expression and tumour histology based on the INPC in which CD44s non-expression is correlated with an unfavourable histological type and the expression of CD44s with a favourable type. Therefore, the analysis of CD44s expression should be recommended as an additional biological marker in the initial routine staging of the disease.

Risk assessment and microbiological profile of infections in paediatric cancer patients with febrile neutropenia

Febrile neutropenia is a common and potentially fatal problem encountered in cancer patients undergoing chemotherapy. We carried out an observational study to evaluate the possible risk factors of developing fever amongst neutropenic children with an underlying malignancy. We also looked at the microbiological profile of causative pathogens in patients with febrile neutropenia. During a study period of 1 year, a total of 90 neutropenic episodes were recorded amongst 57 patients who were on treatment and follow-up during the study period. Multivariate analysis showed that factors such as chemotherapy status, underlying disease, existing central venous catheters, presenting white blood cell counts at chemotherapy, use of steroid therapy or hospitalisation at the onset of neutropenia, were not significant risk factors for developing fever during neutropenic episodes. Although the presence of a central venous catheter was associated with a higher risk of developing fever, it did not reach statistical significance (p=0.11). Of the 90 neutropenic episodes, 59 (65.6%) developed fever and 25 of these had positive blood cultures. The causative organisms include gram-negative bacteria (64%), gram positive bacteria (16%) and fungus (20%). Of the gram-negative organisms, Klebsiella spp. predominated (28%) with the extended spectrum beta-lactamase producing strain forming the majority (16%). Amongst those with fungaemia, Candida spp. and Candida tropicalis formed the majority (8% each) of the isolates.

An unusual mutation in RECQ4 gene leading to Rothmund-Thomson syndrome

Rothmund-Thomson syndrome (OMIM #268400) is a severe autosomal recessive genodermatosis: characterised by growth retardation, hyperpigmentation and frequently accompanied by congenital bone defects, brittle hair and hypogonadism. Mutations in helicase RECQ4 gene are responsible for a subset of cases of RTS. Only six mutations have been reported, thus, far and each affecting the coding sequence or the splice junctions. We report the first homozygous mutation in RECQ4 helicase: 2746-2756-delTGGGCTGAGGC in IVS8 responsible for the severe phenotype associated with RTS in a Malaysian pedigree. We report also a 5321 G-->A transition in exon 17 and the updated list of the RECQ4 gene mutations.

Treatment of chronic hepatitis C virus infection with interferon alfa and ribavirin: sustained response in two patients with transfusion dependent thalassaemia

We describe two cases of transfusion dependent thalassaemics with chronic hepatitis C virus infection whom were treated successfully with interferon and ribavirin, following failure of response or relapse after an initial response to interferon monotherapy. They had sustained virological response for more than twelve months after completing therapy. Transfusion requirements were significantly increased during the combination therapy, probably due to ribavirin-induced haemolysis. Serum ferritin level decreased significantly during the treatment. Combination therapy with interferon alfa and ribavirin may be a feasible treatment option for some nonresponders to prior interferon monotherapy.

Step-down management of gastroesophageal reflux disease

BACKGROUND & AIMS

As the economic burden of gastroesophageal reflux disease (GERD) is largely weighted to maintenance as opposed to initial therapy, switching from more potent to less expensive medication once symptoms are alleviated (step-down therapy) may prove to be most cost-effective. This study aimed to prospectively evaluate the feasibility of step-down therapy in a cohort of patients with symptoms of uncomplicated GERD.

METHODS

Patients whose GERD symptoms were alleviated by proton pump inhibitors (PPIs) were recruited from outpatient general medicine clinics. After baseline demographic and quality of life information were obtained, PPIs were withdrawn from subjects in a stepwise fashion. Primary outcome was recurrence of symptoms during follow-up that required reinstitution of PPIs. Secondary outcomes included changes in quality of life and overall cost of management. Predictors of nonresponse to step-down were assessed.

RESULTS

Seventy-one of 73 enrolled subjects completed the study. Forty-one of 71 (58%) were asymptomatic off PPI therapy after 1 year of follow-up. Twenty-four of 71 (34%) required histamine 2-receptor antagonists, 5/71 (7%) prokinetic agents, 1/71 (1%) both, and 11/71 (15%) remained asymptomatic without medication. Quality of life did not significantly change, whereas management costs decreased by 37%. Multivariable analysis revealed younger age and a dominant symptom of heartburn to predict PPI requirement.

CONCLUSIONS

Step-down therapy is successful in the majority of patients and can decrease costs without adversely affecting quality of life.

Short stature and truncal shortening in transfusion dependent thalassemia patients: results from a thalassemia center in Malaysia

One of the major complications in patients with transfusion dependent thalassemia is growth impairment secondary to iron overload. We studied the growth status in 66 patients with beta-thalassemia major and HbE-beta thalassemia who were transfusion dependent, aged from 2 to 24 years, and 66 controls matched for sex and age. The prevalence of short stature in transfusion-dependent thalassemics was 54.5% compared to 4.5% in control group (p<0.001). Short stature was more prevalent in those above the age of 10 years in this study group (83.3% vs 16.7%). Transfusion dependent thalassemics with short stature were found to have significantly lower mean standing height standard deviation scores (SDS), sitting height SDS and subischial leg length SDS values (p<0.001). There was also a significant difference between the mean sitting height SDS and the mean subischial leg length SDS in our thalassemics with short stature, suggesting that the short stature was due to disproportionate truncal shortening. Serum ferritin levels were significantly higher in transfusion dependent thalassemics who were short compared to those who were of normal height (p = 0.002). However, the mean pre-transfusion hemoglobin levels did not differ significantly between patients with short stature and those with normal height (p = 0.216). The prevalence of short stature also did not differ significantly between those with beta-thalassemia major and those with HbE-beta thalassemia (p = 0.32). This study highlighted the importance of providing optimal treatment in these patients, including monitoring of growth parameters and optimizing iron chelation therapy.

Coduplication of the MLL and FLT3 genes in patients with acute myeloid leukemia

Tandem duplication (TD) of the MLL or FLT3 gene in acute myeloid leukemia (AML) has been reported. We examined whether TD of these two genes occurs simultaneously. We analyzed 13 AML and 2 myelodysplastic syndrome patients, including 6 adult patients with trisomy 11 and 9 pediatric patients with TD of the FLT3 gene, using RT-PCR followed by sequencing. Among these, TD of the MLL and FLT3 genes was found in 5 and 10 patients, respectively. Notably, TD of both the MLL and FLT3 genes (coduplication) was detected in two AML patients, who died 6 and 14 months after diagnosis. TD of these two genes in AML is rare; thus, coduplication of these genes in the same patient is predicted to be very rare. Although the mechanisms of TD of both genes are different, development of TD of both genes may be related to an unknown similar etiology in leukemia because the frequency of coduplication of these genes in a single patient is considered to be very low. Further studies of the coduplication of these genes in AML patients may lead to the clarification of its mechanism and clinical implications.