Validating lactate dehydrogenase (LDH) as a component of the PLASMIC predictive tool (PLASMIC-LDH)

Background

The PLASMIC score is a convenient tool for predicting ADAMTS13 activity of <10%. Lactate dehydrogenase (LDH) is widely used as a marker of haemolysis in thrombotic thrombocytopenic purpura (TTP) monitoring, and could be used as a replacement marker for lysis. We aimed to validate the PLASMIC score in a multi-centre Asia Pacific region, and to explore whether LDH could be used as a replacement marker for lysis.

Methods

Records of patients with thrombotic microangiopathy (TMA) were reviewed. Patients' ADAMTS13 activity levels were obtained, along with clinical/laboratory findings relevant to the PLASMIC score. Both PLASMIC scores and PLASMIC-LDH scores, in which LDH replaced traditional lysis markers, were calculated. We generated a receiver operator characteristics (ROC) curve and compared the area under the curve values (AUC) to determine the predictive ability of each score.

Results

46 patients fulfilled the inclusion criteria, of which 34 had ADAMTS13 activity levels of <10%. When the patients were divided into intermediate-to-high risk (scores 5-7) and low risk (scores 0-4), the PLASMIC score showed a sensitivity of 97.1% and specificity of 58.3%, with a positive predictive value (PPV) of 86.8% and negative predictive value (NPV) of 87.5%. The PLASMIC-LDH score had a sensitivity of 97.1% and specificity of 33.3%, with a PPV of 80.5% and NPV of 80.0%.

Conclusion

Our study validated the utility of the PLASMIC score, and demonstrated PLASMIC-LDH as a reasonable alternative in the absence of traditional lysis markers, to help identify high-risk patients for treatment via plasma exchange.

Assessment of transient changes in oxygen diffusion of single red blood cells using a microfluidic analytical platform

Red blood cells (RBCs) capability to deliver oxygen (O₂) has been routinely measured by P50. Although this defines the ability of RBCs to carry O₂ under equilibrium states, it cannot determine the efficacy of O₂ delivery in dynamic blood flow. Here, we developed a microfluidic analytical platform (MAP) that isolates single RBCs for assessing transient changes in their O₂ release rate. We found that in vivo (biological) and in vitro (blood storage) aging of RBC could lead to an increase in the O₂ release rate, despite a decrease in P50. Rejuvenation of stored RBCs (Day 42), though increased the P50, failed to restore the O₂ release rate to basal level (Day 0). The temporal dimension provided at the single-cell level by MAP could shed new insights into the dynamics of O₂ delivery in both physiological and pathological conditions.

Implementation of cytogenomic microarray with plasma cell enrichment enables better abnormality detection and risk stratification in patients with plasma cell neoplasia than conventional cytogenetics and fluorescence in situ hybridization

The detection of chromosomal abnormalities is important in the diagnosis, prognosis and disease monitoring in plasma cell neoplasia (PCN). However, the gold standard diagnostic techniques of conventional cytogenetics (CC) and fluorescence in situ hybridization (FISH) are hampered by culture difficulties and probe availability. Cytogenomic microarray (CMA), however, is able to surmount such limitations and generate a comprehensive genomic profile with the implementation of plasma cell (PC) enrichment. In this study, we examined 89 bone marrow specimens with CC and FISH without PC enrichment, 35 of which were examined with CMA after PC enrichment. Results revealed that after PC enrichment, CMA was able to detect chromosomal abnormalities in 34 of 35 specimens tested (97.1%), compared to 21 and 32 specimens (60% and 91.4%, respectively) achieved by CC and FISH, respectively, which were similar to the abnormality detection rates among all 89 specimens (59.5% by CC and 92.1% by FISH). In addition, as the only technique capable of detecting copy neutral loss of heterozygosity (CN-LOH) and chromothripsis, CMA appears to be the most powerful tool in risk stratification as it successfully re-stratified 9 (25.7%) and 12 (34.3%) specimens from standard risk (determined by CC and FISH, respectively) to high risk. Based on the encouraging data presented by our study and others, we conclude that implementation of CMA with PC enrichment is of great value in routine clinical workup in achieving a more complete genetic profile of patients with PCN.

Major liver surgery in a Jehovah’s Witness patient: challenges for safe surgery

Jehovah’s Witnesses presenting for major surgery run the risk of major bleeding, which is complicated by the refusal to accept blood transfusion. We present a case of a 63-year-old woman, a Jehovah’s Witness, who was diagnosed with hepatocellular carcinoma and advised for curative laparoscopic liver segmentectomy. Due to the risk of significant intraoperative haemorrhage, her perioperative care was coordinated in a multidisciplinary manner. Informed consent requires the physician to advise on the material risks of undertaking major surgery without blood transfusion and the possible alternatives. Conflicting ethical issues of patient autonomy and beneficence related to refusal of blood products also arise. Perioperative strategies to minimise blood loss, maximise haematopoiesis and tolerance of anaemia to facilitate safe surgery in such patients are also presented. Written patient consent obtained.

Chromosomal microarray analysis is superior in identifying cryptic aberrations in patients with acute lymphoblastic leukemia at diagnosis/relapse as a single assay

INTRODUCTION

Conventional cytogenetics (CC) is important in diagnosis, therapy, monitoring of post-transplant bone marrow, and prognosis assessment of acute lymphoblastic leukemia (ALL). However, due to the nature of ALL, CC often encounters difficulties of complex karyotype, poor chromosome morphology, low mitotic index, or normal cells dividing only. In contrast, chromosomal microarray analysis (CMA) showed a specificity >99% and a sensitivity of 100% in chronic lymphocytic leukemia (CLL) patients. Here, we report our experience with CMA on adult ALL patients.

METHODS

Thirty-three bone marrow/blood samples from ALL patients (aged 18-79 years, median 44) at diagnosis/relapse, analyzed by CC and/or fluorescence in situ hybridization (FISH), were recruited. Chromosomal microarray analysis results were compared with CC. Fluorescence in situ hybridization analysis, if available, was applied when there was a discrepancy.

RESULTS

Copy-neutral loss-of-heterozygosity (CN-LOH) was found in 8 cases (24.2%). Only CN-LOH at 9p was recurrent (3 cases, 9.1%). Copy number alterations (CNAs) were detected in 6 of 9 cases (66.7%) with normal karyotypes, in 3 of 5 cases (60.0%) with sole "balanced" translocations, and in 18 of 19 cases (94.7%) with complex karyotypes. Common CNAs involved CDKN2A/2B (30.3%), IKZF1 (27.3%), PAX5 (9.1%), RB1 (9.1%), BTG1 (6.7%), and ETV6 (6.7%), which regulate cell cycle, B lymphopoiesis, or act as tumor suppressors in ALL. Copy number alteration detection rate by CMA was 81.8% (27 of 33 cases) as compared to 57.6% (19 of 33 cases) by CC.

CONCLUSION

Incorporation of CMA as a routine clinical test at the time of diagnosis/relapse, in conjunction with CC and/or FISH, is highly recommended.

Symmetry recovery of cell-free layer after bifurcations of small arterioles in reduced flow conditions: effect of RBC aggregation

Heterogeneous distribution of red blood cells (RBCs) in downstream vessels of arteriolar bifurcations can be promoted by an asymmetric formation of cell-free layer (CFL) in upstream vessels. Consequently, the CFL widths in subsequent downstream vessels become an important determinant for tissue oxygenation (O2) and vascular tone change by varying nitric oxide (NO) availability. To extend our previous understanding on the formation of CFL in arteriolar bifurcations, this study investigated the formation of CFL widths from 2 to 6 vessel-diameter (2D-6D) downstream of arteriolar bifurcations in the rat cremaster muscle (D = 51.5 ± 1.3 μm). As the CFL widths are highly influenced by RBC aggregation, the degree of aggregation was adjusted to simulate levels seen during physiological and pathological states. Our in vivo experimental results showed that the asymmetry of CFL widths persists along downstream vessels up to 6D from the bifurcating point. Moreover, elevated levels of RBC aggregation appeared to retard the recovery of CFL width symmetry. The required length of complete symmetry recovery was estimated to be greater than 11D under reduced flow conditions, which is relatively longer than interbifurcation distances of arterioles for vessel diameter of ∼50 μm. In addition, our numerical prediction showed that the persistent asymmetry of CFL widths could potentially result in a heterogeneous vasoactivity over the entire arteriolar network in such abnormal flow conditions.

Implications of the Updated 2013 American Society of Clinical Oncology/College of American Pathologists Guideline Recommendations on Human Epidermal Growth Factor Receptor 2 Gene Testing Using Immunohistochemistry and Fluorescence In Situ Hybridization for Breast Cancer

Context

Human epidermal growth factor receptor 2 (HER2/neu) amplification is used as a predictive marker for trastuzumab treatment in breast cancer. Both immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) testing algorithms have been based on the 2007 American Society of Clinical Oncology/College of American Pathologists (ASCO/CAP) guidelines. In late 2013, the guidelines were updated with new scoring criteria.

Objective

—To assess the impact of the revised ASCO/CAP recommendations on both IHC and FISH results by using the dual-color HER2/neu and centromeric FISH probes.

Design

Retrospective analysis of 590 invasive carcinomas with concurrent IHC and dual-color HER2/neu and centromeric 17 (CEP17) FISH results, based on 2007 ASCO/CAP guidelines, was conducted from July 2011 to June 2013. With the revised guidelines, patients were recategorized and concordance rates between the 2 assays were recalculated.

Results

—Overall concordance rates for FISH and IHC decreased from 94.9% to 93.8% with reclassification. Negative FISH cases decreased from 79.1% to 69.3%. However, equivocal FISH cases were significantly increased from 0.7% to 9.5%, leading to more retesting. Both positive IHC and FISH cases were also noted to be increased, leading to more patients being eligible for trastuzumab treatment, especially those patients with concurrent HER2/neu and CEP17 polysomy. Approximately 1% of patients with initial FISH negative results were reclassified as having positive results when both the ratios and average copy number of HER2/neu were considered under the revised guidelines.

Conclusions

The revised 2013 ASCO/CAP guidelines can potentially lead to more patients being eligible for trastuzumab therapy but additional retesting is to be expected owing to an increased number of equivocal FISH cases.

Amplification of 1q21 and other abnormalities in multiple myeloma patients from a tertiary hospital in singapore

Much effort has been made to stratify multiple myeloma patients for targeted therapy. However, responses have been varied and improved patient stratifications are needed. Forty-five diagnostic samples from multiple myeloma patients (median age 65 years) were stratified cytogenetically as 15 having non-hyperdiploidy, 20 having hyperdiploidy and 10 having a normal karyotype. Fluorescence in situ hybridization (FISH) assays with FGFR3/IGH, CCND1/IGH, IGH/MAF, RB1 and TP53 probes on bone marrow samples showed that IGH rearrangements were the most common abnormality in the non-hyperdiploid group but these were also found among hyperdiploid patients and patients with normal cytogenetics. Of these, FGFR3/IGH rearrangements were most frequent. Deletion of RB1/monosomy 13 was the most common genetic abnormality across the three groups and was significantly higher among non-hyperdiploid compared to hyperdiploid patients. On the other hand, the study recorded a low incidence of TP53 deletion/monosomy 17. The FGFR3/IGH fusion was frequently seen with RB1 deletion/monosomy 13. FISH with 1p36/1q21 and 6q21/15q22 probes showed that amplification of 15q22 was seen in all of the hyperdiploid patients while amplification of 1q21, Amp(1q21), characterized non-hyperdiploid patients. In contrast, deletions of 1p36 and 6q21 were very rare events. Amp(1q21), FGFR3/IGH fusion, RB1 deletion/monosomy 13, and even TP53 deletion/monosomy 17 were seen in some hyperdiploid patients, suggesting that they have a less than favorable prognosis and require closer monitoring.

CpG Oligonucleotide and Interleukin 2 stimulation enables higher cytogenetic abnormality detection rates than 12-o-tetradecanolyphorbol-13-acetate in Asian patients with B-cell chronic lymphocytic leukemia (B-CLL)

The present study was designed to compare abnormality detection rates using DSP30 + IL2 and 12-O-Tetradecanoylphorbol-13-acetate (TPA) in Asian patients with B-CLL. Hematological specimens from 47 patients (29 newly diagnosed, 18 relapsed) were established as 72 h-DSP30 + IL2 and TPA cultures. Standard methods were employed to identify clonal aberrations by conventional cytogenetics (CC). The B-CLL fluorescence in situ hybridization (FISH) panel comprised ATM, CEP12, D13S25, and TP53 probes. DSP30 + IL2 cultures had a higher chromosomal abnormality detection rate (67 %) compared to TPA (44 %, p < 0.001). The mean number of analyzable metaphases and abnormal metaphases per slide was also higher (p < 0.005, p < 0.001, respectively). Culture success rate, percentage of complex karyotype, and percentage of non-clonal abnormal cell were not significantly different (p > 0.05). Thirteen cases with abnormalities were found exclusively in DSP30 + IL2 cultures compared to one found solely in TPA cultures. DSP30 + IL2 cultures were comparable to the FISH panel in detecting 11q-, +12 and 17p- but not 13q-. It also has a predilection for 11q- bearing leukemic cells compared to TPA. FISH had a higher abnormality detection rate (84.1 %) compared to CC (66.0 %) with borderline significance (p = 0.051), albeit limited by its coverage. In conclusion, DSP30 + IL2 showed a higher abnormality detection rate. However, FISH is indispensable to circumvent low mitotic indices and detect subtle abnormalities.

The clinical utility of conventional karyotyping in the detection of cytogenetic abnormalities in soft tissue tumours: an Asian institutional experience

OBJECTIVES

To assess the clinical utility of conventional karyotyping as a diagnostic tool in soft tissue tumours amidst the increasing use of molecular cytogenetics.

DESIGN

Case series.

SETTING

Singapore General Hospital, an Asian institution.

PARTICIPANTS

A total of 35 participants (18 male and 17 female) aged 15 to 81 years were included in this study. Conventional karyotyping of 35 consecutive fresh soft tissue tumour specimens was performed over 4 years and the results were analysed.

RESULTS

Of the 35 cases of soft tissue tumours reviewed, chromosome abnormalities were detected in 22 (63%) cases, 11 (31%) showed a normal karyotype, and 2 (6%) had culture failure. Of the 22 cases with abnormal karyotype, nine (41%) cases showed recurring aberrations: Ewing's sarcomas (n=2), desmoplastic small round cell tumour (n=1), synovial sarcomas (n=3), myxoid liposarcomas (n=2), and lipoma (n=1). One lipoma case had a t(2;12)(q23;q15) in which 2q23 breakpoint was not reported before. Chromosomal aberration involving 12q15 breakpoint has been shown in a previous study to be indicative of a lipoma-like liposarcoma. Another lipoma case had addition of 5q15 and 9p13 together with a balanced aberration of t(12;13) (q13;q12) which were novel aberrations. One synovial sarcoma case showed t(3;7)(q21;p13) which was an uncharacteristic aberration.

CONCLUSION

Conventional karyotyping demonstrated utility as a genome-wide screening tool for soft tissue tumours and an adjunct diagnostic tool in the event histopathology results were doubtful. With the more widespread use of karyotyping, novel recurring chromosomal aberrations may be discovered.

Differential outcomes in an extended family with constitutional t(11;22)(q23.3;q11.2)

The t(11;22) rearrangement is the most common recurrent familial reciprocal translocation in man. Heterozygote carriers are phenotypically normal but are at risk of subfertility in the male, miscarriages, and producing chromosomally unbalanced offspring. The unbalanced progeny usually results from an extra der(22) chromosome resulting from a 3:1 malsegregation. We present here a family with t(11;22). Of six siblings, three were found to be carriers following prenatal diagnosis of the proband fetus. Neither of the two married carrier siblings have a live born child. In keeping with the prevailing knowledge of the pregnancy outcomes of heterozygote carriers, between the siblings they had recurrent miscarriages, a fetus with a +der(22) chromosome, and other subfertility issues resulting in multiple failed in vitro fertilization cycles with preimplantation genetic diagnosis. However, unlike the siblings, their extended family comprising their heterozygote translocation mother, married aunts and an uncle had normal fertility and a lack of a history of miscarriages or an abnormal child. The differing outcomes may be related to the male partners having additional semen anomalies which may further exacerbate problems associated with the t(11;22). Because the t(11;22) rearrangement tends to run in families, it is recommended that chromosome studies are offered to family members of an affected relative as an option, and provide them with appropriate genetic counseling so that they will have the necessary information with regard to their risk for subfertility, miscarriages, and production of viable unbalanced offspring. Follow-up prenatal diagnosis should also be offered to affected expectant family members, especially after preimplantation genetic diagnosis.

Cytogenetic and molecular aberrations of multiple myeloma patients: a single-center study in Singapore

BACKGROUND

Much is known about the cytogenetic lesions that characterize multiple myeloma (MM) patients from the USA, Europe, and East Asia. However, little has been published about the disease among Southeast Asians. The aim of this study was to determine the chromosomal abnormalities of MM patients in our Singapore population.

METHODS

Forty-five newly-diagnosed, morphologically confirmed patients comprising 18 males and 27 females, aged 46 - 84 years (median 65 years) were investigated by karyotyping and fluorescence in situ hybridization (FISH). FISH employing standard panel probes and 1p36/1q21 and 6q21/15q22 probes was performed on diagnostic bone marrow samples.

RESULTS

Thirty-four cases (75.6%) had karyotypic abnormalities. Including FISH, a total detection rate of 91.1% was attained. Numerical and complex structural aberrations were common to both hyperdiploid and non-hyperdiploid patients. Numerical gains of several recurring chromosomes were frequent among hyperdiploid patients while structural rearrangements of several chromosomes including 8q24.1 and 14q32 characterized non-hyperdiploid patients. With FISH, immunoglobulin heavy chain (IGH) gene rearrangements, especially fibroblast growth factor receptor 3 (FGFR3)/IGH and RB1 deletion/monosomy 13 were the most common abnormalities (43.4%). Amplification 1q21 was 10 times more frequent (42.5%) than del(1p36) and del(6q21).

CONCLUSIONS

We have successfully reported the comprehensive cytogenetic profiling of a cohort of newly-diagnosed myeloma patients in our population. This study indicates that the genetic and cytogenetic abnormalities, and their frequencies, in our study group are generally similar to other populations.

HER2/neu revisited: quality and interpretive issues

BACKGROUND

Immunohistochemistry (IHC) and fluorescence in situ hybridisation (FISH) are the only tests currently approved by the US Food and Drug Administration for classifying which patients will benefit from trastuzumab therapy. The accuracy of these two testing methods can be adversely affected by a variety of pre-analytical, analytical and post-analytical factors. According to the latest published recommendations of the panel of the Joint Committee of the American Society of Clinical Oncology and College of American Pathologists for HER2/neu testing, laboratories performing IHC and FISH for HER2/neu status in breast cancer are now required to have a high concordance of at least 95% between IHC and FISH, significantly higher than that in the published literature.

AIM

To perform a retrospective analysis of the concordance of IHC and FISH analysis for HER2/neu at Singapore General Hospital and review potential causes of disparity between these two methods.

METHOD

A retrospective review of a total of 106 invasive ductal carcinomas evaluated for HER2/neu at the Department of Pathology, Singapore General Hospital between 2007 and 2008 were included in the study. The initial HER2/neu immunostained slides were reviewed independently without knowledge of FISH results, and concordance between IHC and FISH was determined.

RESULTS

Concordance between IHC and FISH assay was excellent and within the published range (104/106=98.1%). The discordant cases represent a well-recognised subset of genetic heterogeneity in HER2/neu, which is known to contribute to positive IHC and negative FISH tests.

Rapid aneuploidy screening with fluorescence in-situ hybridisation: is it a sufficiently robust stand-alone test for prenatal diagnosis?

OBJECTIVES

To assess the clinical utility of fluorescence in-situ hybridisation with chromosomes 13, 18, 21, X and Y as a stand-alone test in detecting chromosomal abnormalities, and the types of chromosomal abnormalities missed.

DESIGN

Retrospective analysis.

SETTING

A restructured Government hospital in Singapore and an academic hospital in the United States.

PARTICIPANTS

Cytogenetic data of prenatal specimens and results of fluorescence in-situ hybridisation of 5883 patients performed between January 2000 and August 2007 were reviewed.

RESULTS

Fluorescence in-situ hybridisation detected 558 (9.5%) patients with chromosomal abnormalities. Abnormal ultrasounds (70%) and maternal serum screens (21%) were the most indicative of chromosomal abnormalities. When comparing fluorescence in-situ hybridisation data with karyotype results for the five chromosomes of interest, the sensitivity and specificity were 99.3% and 99.9%, respectively. When comparing fluorescence in-situ hybridisation data with karyotype results for all chromosomes, the sensitivity decreased to 86.8%, whereas the specificity remained at 99.9%. Of 643 cases with karyotype abnormalities, 85 were fluorescence in-situ hybridisation-negative (false negative rate, 13.2%), which included structural rearrangements, chromosome mosaicism, and other trisomies. Despite abnormal ultrasound indications, fluorescence in-situ hybridisation missed 32 cases which included structural rearrangements, mosaicisms, and other trisomies.

CONCLUSION

This study does not support fluorescence in-situ hybridisation as a stand-alone test. Institutions supporting fluorescence in-situ hybridisation as a stand-alone test must seriously consider the risks of a missed diagnosis.

Bone Marrow Cytogenetics Workup: Application of Lean Management System to Determine if Additional Cell Workup is Helpful and Necessary to Analysis

Introduction: High workload volumes in a Cytogenetics laboratory can lead to long result turn-around times (TAT). This study aimed to improve laboratory efficiency by adopting Lean Management System initiatives to increase productivity through the elimination of wastes. This study examined if the prerequisite 20-cell analysis was sufficient for a conclusive result or if additional cell workup was necessary to ascertain the presence of a previous chromosome abnormality among cases on follow-up, or when a single abnormal cell was encountered during the analysis to determine the presence of a clone. Materials and Methods: The karyotype results of cases that had additional workup were retrieved from among 8040 bone marrow cases of various haematological disorders performed between June 2003 and June 2008. Results: Of 8040 cases analysed, 2915 cases (36.3%) had additional cell workup. Only 49 cases (1.7%) led to the establishment of a clone. The majority of these cases could have been resolved without the additional workup, especially if fluorescence in situ hybridization (FISH) or polymerase chain reaction (PCR)-based assays had been utilised. Conclusion: This study shows that the additional workup procedure is redundant. The time saved by discontinuing the workup procedure can be used to analyse other cases, leading to increased laboratory efficiency and a faster TAT without compromise to patient care. The practice of additional workup over and above the 20-cell analysis should be dispensed with as little benefit was derived for the amount of additional manpower expended. FISH or PCR-based assays should be utilised to elucidate a case further. Key words: Clone, Fluorescence in situ hybridization, Haematological disorders, Karyotyping, Laboratory efficiency

Bone marrow cytogenetics workup: Application of lean management system to determine if additional cell workup is helpful and necessary to analysis

INTRODUCTION

High workload volumes in a Cytogenetics laboratory can lead to long result turn-around times (TAT). This study aimed to improve laboratory efficiency by adopting Lean Management System initiatives to increase productivity through the elimination of wastes. This study examined if the prerequisite 20-cell analysis was sufficient for a conclusive result or if additional cell workup was necessary to ascertain the presence of a previous chromosome abnormality among cases on follow-up, or when a single abnormal cell was encountered during the analysis to determine the presence of a clone.

MATERIALS AND METHODS

The karyotype results of cases that had additional workup were retrieved from among 8040 bone marrow cases of various haematological disorders performed between June 2003 and June 2008.

RESULTS

Of 8040 cases analysed, 2915 cases (36.3%) had additional cell workup. Only 49 cases (1.7%) led to the establishment of a clone. The majority of these cases could have been resolved without the additional workup, especially if fluorescence in situ hybridization (FISH) or polymerase chain reaction (PCR)-based assays had been utilised.

CONCLUSION

This study shows that the additional workup procedure is redundant. The time saved by discontinuing the workup procedure can be used to analyse other cases, leading to increased laboratory efficiency and a faster TAT without compromise to patient care. The practice of additional workup over and above the 20- cell analysis should be dispensed with as little benefit was derived for the amount of additional manpower expended. FISH or PCR-based assays should be utilised to elucidate a case further.

Synovial sarcoma of the kidney: a report of 4 cases with pathologic appraisal and differential diagnostic review

BACKGROUND

Synovial sarcoma of the kidney is rare. It is clinicoradiologically indistinguishable from the more frequently encountered renal cell carcinoma. Histologically it needs to be differentiated from other spindle cell lesions occurring within the kidney, including a spectrum of benign to malignant tumors. Among malignant spindle cell tumors of the kidney, mimics of synovial sarcoma are sarcomatoid renal cell carcinoma, sarcomatoid urothelial carcinoma and other primary sarcomas, such as leiomyosarcoma and malignant fibrous histiocytoma.

CASES

Four cases of synovial sarcoma originated in the kidney, with this report focusing on clinicopathologic and differential diagnostic features.

CONCLUSION

The correct diagnosis of synovial sarcoma requires support by an immunohistochemical panel as well as adjunctive investigations like polymerase chain reaction and fluorescence in situ hybridization to determine the presence of the SYT-SSX fusion gene and translocation (X,18), respectively.

Holoprosencephaly: An Antenally-diagnosed Case Series and Subject Review

Introduction: Holoprosencephaly (HPE) is an uncommon congenital failure of forebrain development. Although the aetiology is heterogeneous, chromosomal abnormalities or a monogenic defect are the major causes, accounting for about 40% to 50% of HPE cases. At least 7 genes have been positively implicated, including SHH, ZIC2, SIX3, TGIF, PTCH1, GLI2, and TDGF1. Clinical Picture: Twelve antenatally- and 1 postnatally-diagnosed cases are presented in this study. These comprised 6 amniotic fluid, 3 chorionic villus, 2 fetal blood, 1 peripheral blood, and 1 product of conception. Outcome: The total chromosome abnormality rate was 92.3%, comprising predominantly trisomy 13 (66.7%). There was 1 case of trisomy 18, and 3 cases of structural abnormalities, including del13q, del18p, and add4q. Conclusion: Despite the poor outcome of an antenatally-diagnosed HPE and the likely decision by parents to opt for a termination of pregnancy, karyotyping and/or genetic studies should be performed to determine if a specific familial genetic or chromosomal abnormality is the cause. At the very least, a detailed chromosome analysis should be carried out on the affected individual. If the result of highresolution karyotyping is normal, Fluorescence in situ hybridisation (FISH) and/or syndromespecific testing or isolated holoprosencephaly genetic testing may be performed. This information can be useful in making a prognosis and predicting the risk of recurrence. Key words: Chromosomes, Genes, Karyotyping, Trisomies

Holoprosencephaly: an antenatally-diagnosed case series and subject review

INTRODUCTION

Holoprosencephaly (HPE) is an uncommon congenital failure of forebrain development. Although the aetiology is heterogeneous, chromosomal abnormalities or a monogenic defect are the major causes, accounting for about 40% to 50% of HPE cases. At least 7 genes have been positively implicated, including SHH, ZIC2, SIX3, TGIF, PTCH1, GLI2, and TDGF1.

CLINICAL PICTURE

Twelve antenatally- and 1 postnatally-diagnosed cases are presented in this study. These comprised 6 amniotic fluid, 3 chorionic villus, 2 fetal blood, 1 peripheral blood, and 1 product of conception.

OUTCOME

The total chromosome abnormality rate was 92.3%, comprising predominantly trisomy 13 (66.7%). There was 1 case of trisomy 18, and 3 cases of structural abnormalities, including del13q, del18p, and add4q.

CONCLUSION

Despite the poor outcome of an antenatally-diagnosed HPE and the likely decision by parents to opt for a termination of pregnancy, karyotyping and/or genetic studies should be performed to determine if a specific familial genetic or chromosomal abnormality is the cause. At the very least, a detailed chromosome analysis should be carried out on the affected individual. If the result of high resolution karyotyping is normal, Fluorescence in situ hybridisation (FISH) and/or syndrome-specific testing or isolated holoprosencephaly genetic testing may be performed. This information can be useful in making a prognosis and predicting the risk of recurrence.

Loss of the extra chromosome 21 in a patient with Down syndrome and myelodysplasia

Monosomy 21 is a rare acquired karyotypic abnormality associated with myeloid disorders. Occurrence of loss of one chromosome 21 in the background of trisomy 21 in Down syndrome, resulting in the pseudo-normalization of trisomy 21, is a novel finding. The case is described of a patient with Down syndrome who acquired such a genetic abnormality as a result of myelodysplastic syndrome.

In Vivo Liver Electroporation: Optimization and Demonstration of Therapeutic Efficacy

Adverse effects (death and leukemogenesis) from viral vector-mediated gene therapy have renewed interest in plasmids as safer, more scalable, simple, and cost-effective vectors. Electroporation and hydrodynamic delivery are two techniques that improve the efficiency of plasmid-mediated gene transfer. The liver is a good tissue platform for targeted transfer of therapeutically relevant genes for correction of metabolic disorders, for example, hemophilia A. However, in vivo electroporation of liver has not yet been shown to achieve therapeutic efficacy of systemically active, secreted transgenic proteins. We have investigated the effect of field strength, pulse duration, pulse number, electrical waveforms, electrode contact area, plasmid administration routes, and injection technique on the efficiency of in vivo electrotransfer of naked plasmid to liver. Plasmid injection into a systemic vein was superior to intrahepatic injection. Unlike in vivo muscle electroporation, high-voltage pulses and microsecond pulses offered no advantage. Optimal electroporation conditions were 8-10 uni- or bipolar pulses of 20 msec, each at 250 V/cm. Using a nonhydrodynamic technique that greatly enhanced electrotransfer efficiency with minimal tissue injury, we demonstrate for the first time that liverdirected in vivo electroporation of factor VIII cDNA achieved significant phenotypic correction in hemophilic mice.

The incidence and patterns of BCR/ABL rearrangements in chronic myeloid leukaemia (CML) using fluorescence in situ hybridisation (FISH)

INTRODUCTION

Chronic myeloid leukaemia (CML) is characterised by the formation of the BCR/ABL fusion gene, usually as a result of the Philadelphia (Ph) translocation between chromosomes 9 and 22.

MATERIALS AND METHODS

The incidence of both typical and atypical BCR/ ABL gene rearrangements was determined in 110 patients suspected of CML using dual fusion fluorescence in situ hybridisation (DF-FISH) probes.

RESULTS

Eighty-seven per cent of CML patients showed Ph translocation while 13% were negative for the Ph chromosome. About 71.9% of Ph-positive patients displayed the typical DF-FISH signal pattern. Atypical patterns among the Ph-positive patients included the concurrent loss of residual proximal 9q and distal 22q (10.4%), complex translocation with additional partners (9.4%), supernumerary Ph (3.1%), loss of residual 9q sequences proximal to breakpoint (3.1%), and deletion of distal derivative 22q signal (2.1%). Cryptic genetic alterations with loss of proximal 9q sequences were found in 13.5% of CML Ph-positive patients, which is associated with poor prognosis. Fusion signals were detected in 57.1% of CML Ph-negative patients, indicating cryptic BCR/ABL rearrangements (i.e., masked Ph).

CONCLUSION

FISH is able to detect BCR/ABL fusion in CML with masked or variant Ph not apparent with conventional karyotyping. Establishment of signal patterns with FISH is important as atypical patterns may have clinical prognostic implications.

FVIII gene delivery by muscle electroporation corrects murine hemophilia A

BACKGROUND

Hemophilia A treatment relies on costly factor VIII (FVIII) replacement that may transmit iatrogenic viral diseases. Viral vectors and cell implants are being developed as improvements. We investigated in vivo electroporation of naked DNA as a safe and simple method for correcting FVIII deficiency.

METHODS

B-domain-deleted murine FVIII cDNA expression plasmids were constructed with CMV and elongation factor 1alpha promoters for characterisation in murine C2C12 myoblasts. The construct conferring highest in vitro FVIII secretion was electroporated into skeletal muscle of FVII null mice in vivo for phenotypic correction using a protocol that minimised tissue injury.

RESULTS

B-domain-deleted murine FVIII cDNA plasmids induced FVIII secretion from stably transfected C2C12 myoblasts (0.54+/-0.20 mU/day/10(5) cells). Phenotypic correction of hemophilic mice was more consistently achieved using a protocol for in vivo electroporation of gastrocnemius muscle with FVIII cDNA that reduced tissue injury by the use of plate electrodes, hyaluronidase pre-treatment and lower field strength. This technique was associated with <10% muscle necrosis. Activated partial thromboplastin time decreased from 51.4+/-3.3 to 34.7+/-1.1 (mean+/-s.e.m.) seconds (p=0.0004) following in vivo electroporation (0.1 mg plasmid/limb; 8x20 ms pulses, 175 V/cm, 1 Hz) of hemophilic mice. All hemophilic mice (8/8) survived hemostatic challenge after muscle electroporation with FVIII cDNA, whereas all (9/9) untreated hemophilic mice died. Plasmid DNA was detectable only in electroporated muscle and not in all other organs tested, including gonads.

CONCLUSION

In vivo intramuscular electroporation of naked FVIII plasmid successfully corrects murine hemophilia.

Acute promyelocytic leukemia with PML-RARA fusion on i(17q) and therapy-related acute myeloid leukemia

We describe a patient with acute promyelocytic leukemia (APL) and the karyotype 46,XX,i(17)(q10) with PML-RARA fusion gene detected by fluorescence in situ hybridization (FISH) and nested reverse transcriptase-polymerase chain reaction (RT-PCR). FISH using dual-color translocation probes for PML (promyelocytic leukemia) and RARA (retinoic acid receptor-alpha) showed fusion signal for PML-RARA on both arms of i(17q). The patient attained complete remission (CR) with all-trans retinoic acid treatment and became PML-RARA negative. One year later, while PML-RARA negative on FISH and RT-PCR, the patient presented with thrombocytopenia. Bone marrow examination suggested an acute monoblastic leukemia (AML-M5a) including the karyotype 46,XX,t(8;16) (p11.2;p13.3),inv(11)(p15q22 approximately q23)[11]/47,idem,+i(8)(q10)[9]. She is currently in CR. The occurrence of therapy related acute leukemia after successful therapy for APL is an emerging problem.

Cytogenetic abnormalities in de novo acute myeloid leukemia in adults: relation to morphology, age, sex and ethnicity - a single center study from Singapore

BACKGROUND

Cytogenetic analysis performed at diagnosis is considered to be the most valuable prognostic factor in acute myeloid leukemia (AML). Large systematic studies of cytogenetic abnormalities in AML patients from Southeast Asia are not available. The karyotypic patterns in AML patients from a single center in Singapore were studied and compared with reports from other regions of the world to identify possible geographic heterogeneity.

METHODS

Analysis was performed on 501 consecutive de novo AML patients diagnosed according to the FAB criteria in the Singapore General Hospital. The cytogenetic findings were analyzed for possible associations between karyotypic pattern and the age, gender, ethnicity as well as morphological (FAB) subtypes.

RESULTS

A total of 454 patients were studied of which 275(61%) had abnormal cytogenetics(median age 48 years). The t(15;17) and trisomy 8 were the most frequent karyotypic abnormalities - seen in 52(11%) and 33(7.3%) cases, respectively. Inv(lf) and t(16;16) were uncommon, seen only in five (1.1%) cases. The abnormalities del 5/5q and del 7/7q were seen in 30(6.6%) and 32(7%) of the cases. Complex karyotypes were seen in 78(17%) of the cases.Recurrent cytogenetic abnormalities correlated with the FAB subtypes. In all, 21 novel cytogenetic abnormalities were observed.

CONCLUSIONS

Certain differences such as the age at presentation and frequency of recurrent balanced translocations were noted in comparison to previous reports. These point to the need for extensive epidemiological studies to clarify the role of genetic as well as geographic heterogeneity in the pathogenesis of AML.

The importance of high resolution chromosome analysis in the diagnosis of birth defects: case reports of holoproscencephaly and cystic hygroma

INTRODUCTION

The goal of cytogenetics is the detection of chromosomal abnormalities, achieved by the analysis of adequate numbers of metaphases at the appropriate bands per haploid set (BPHS).

CLINICAL PICTURE

Two cases presented here include a foetal blood sample (FBS) of a 33-week-old referred with holoproscencephaly by ultrasonography, and an amniotic fluid (AF) specimen of a 14-week-old foetus with cystic hygroma, cardiac and renal defects.

OUTCOME

The FBS had a deletion at 18p11.31. Another laboratory had earlier given a normal cytogenetic result on its AF sample. In the second case, an unbalanced 46,XY,der(5)ins(5;3) (q33.1;q26.2q27)mat karyotype was obtained with the AF sample. In both cases, the abnormalities were more obvious when band levels were > or =450 BPHS.

CONCLUSION

This report underscores the importance of obtaining longer chromosome preparations above the current recommended 400 BPHS for prenatal specimens. This is particularly important in cases with abnormal ultrasound findings suggestive of an underlying chromosomal pathology.

Radionuclide synovectomy and chronic haemophilic synovitis in Asians: a retrospective study

Radionuclide synovectomy has been identified as the procedure of choice in treating chronic haemophilic synovitis among Caucasian populations. Its effectiveness among East Asians has not been studied. A retrospective study was carried out on 12 Asian haemophiliacs who underwent 12 radionuclide synovectomies. The average follow-up was 30.7 months (range 6-55) for primary procedures. 32P chromic phosphate and 188Re-tin colloid were injected into target joints according to protocol. There was a significant 80% decrease in the median frequency of haemarthrosis from 1.4 per month (range 0.2-7.0) to 0.25 per month (range 0.0-1.8) (P<0.05). Half of the patients had excellent results by 1 year of synovectomy. The median factor usage for target joint haemarthrosis postsynovectomy was 792 units per month (range 0-3209) reduced significantly from a presynovectomy level of 1452 units per month (range 306-7125) (P<0.05). Patients also reported a reduction in joint pain scores, and an improvement in joint mobility and quality of life. The majority of patients were satisfied with the overall outcome of radionuclide synovectomy. Radionuclide synovectomy appears to be effective in reducing the incidence of target joint haemarthrosis and quantity of factor usage for such bleeds among Asians with haemophilic synovitis.

Primary pleural synovial sarcoma. A case report and review of the literature

Synovial sarcoma (SS) is an uncommon soft tissue tumor that occurs primarily in the extremities of young adults, especially in the periarticular region. In this report, we describe the rare occurrence of primary SS of the pleura in a 15-year-old boy. Histologically, the tumor demonstrated monophasic morphologic findings and showed positive staining with vimentin and Bcl-2 and focally for cytokeratin CK7. Fluorescent in situ hybridization identified t(X;18) translocation. The patient developed recurrences 20 months following resection of the tumor. The literature on this uncommon entity is reviewed, and its histogenesis, differential diagnoses, and cytologic features are also discussed.

An evaluation of point-of-care instrument for monitoring anticoagulation level in adult cardiac patients

INTRODUCTION

Rapid point-of-care measurement of anticoagulation has become feasible with the advent of new portable devices and offers the potential for home monitoring. This study evaluates the accuracy and feasibility of such a point-of-care device, the ProTime analyser as compared with standard laboratory method (IL MCL2) for monitoring the International Normalised Ratio (INR) level in cardiac patients on oral anticoagulation therapy.

MATERIALS AND METHODS

Fifty patients were studied. The majority were male (86% versus 14%). Chinese accounted for 37(74%) whereas Malay and Indian, constituted 9(18%) and 4(8%) respectively. The mean age was 55 +/- 12 years. Prosthetic heart valve replacement (46%) and atrial fibrillation (38%) were among the main indications for anticoagulation. The mean dosage of warfarin was 3.0 +/- 1.5 mg (range 1.0 to 6.5 mg) and the INR results ranged from 0.83 to 4.69 (based on the hospital laboratory method). Fingerstick and venous blood samples were collected from every patient and subjected to analysis by ProTime and IL MCL2 analysers.

RESULTS

There was a good correlation of INRs between ProTime venous and IL MCL2 venous, ProTime fingerstick and IL MCL2 venous and ProTime venous and ProTime fingerstick samplings, with correlation coefficients (r) of 0.9248, 0.9403 and 0.9557, respectively. The Bland-Altman plot also showed a good correlation between the methods used without any systematic bias (limits of agreement ranged from -0.422 to +0.606 INR units on average).

CONCLUSION

This rapid point-of-care device appears to have an acceptable level of accuracy for measuring INR values in the recommended target ranges in adult cardiac patients on oral anticoagulation therapy.

Four pregnancies in two patients with essential thrombocythaemia--a case report

INTRODUCTION

We report our experience of 4 pregnancies in 2 patients who had essential thrombocythaemia (ET).

CLINICAL PICTURE

Two patients with ET were managed with a variety of therapeutic approaches including the use of low-dose aspirin, plateletpheresis, hydroxyurea and alpha-interferon in the course of their 4 pregnancies.

TREATMENT AND OUTCOME

One patient had 2 successful pregnancies despite having platelet counts in excess of 1000 x 10(9)/L antenatally. The second patient had an intrauterine fetal death during the third trimester of her first pregnancy but had a successful second pregnancy.

CONCLUSION AND CLINICAL IMPLICATIONS

Management of ET in pregnancy is still very much individualized. The impact of various treatment modalities on the pregnancy outcome remains to be proven but a favourable pregnancy outcome is possible.

A case report of adult T-cell leukaemia/lymphoma (ATLL)

Adult T-cell leukaemia/lymphoma (ATLL) is a unique disease with distinct manifestations, a characteristic phenotype and a likely retroviral aetiology. It is unusual in Southeast Asia, though more commonly seen in some countries like Japan. We report a case of this disease in a 71-year-old man in Singapore who presented with papular erythematous eruptions for 6 years and subsequently developed generalised lymphadenopathy. He was diagnosed to have ATLL and, despite an initial response, became resistant to combination chemotherapy. We discuss the aetiology, characteristics and management of this interesting disease.

Activated protein C resistance: a study among 60 thromboembolic patients in the Singapore population

Resistance to activated protein C (APC-R) is the commonest inherited cause of thrombosis among Caucasians. Few studies have been carried out on its prevalence in Asians. We conducted a prospective study on 60 patients with thromboembolism to determine its prevalence in our local population. The Factor V Leiden (VaQ506) mutation associated with this condition was detected by amplification of the Factor V gene by polymerase chain reaction (PCR) and digestion of the fragment with Mnl I. Three patients were found to be heterozygous for this mutation. None of the 3 patients had other concomitant hypercoagulable states. In addition, we studied the prevalence of this condition in Malays which was found to be 0.5%. Our study suggests that the incidence of APC-R is much lower here compared to the West.

Highly complex chromosomal rearrangement of chromosome 9 in a case of chronic myeloid leukemia

A 63-year-old man with chronic myeloid leukemia (CML) was found to have a new complex Philadelphia translocation. All of the bone marrow cells had a rearrangement of a five-way translocation, t(9;22;10;12;1), involving a single chromosome 9. The patient went into blast crisis two years after initial diagnosis and the karyotype remained unchanged. He died in blast crisis 10 months later. We believe this case is a unique 5-way translocation in which four chromosomes were translocated to a single chromosome.

Persistence of red cell aplasia despite treatment of malignant thymoma: a case report

Pure cytopenias are well-recognised associations with malignant thymoma. We present a case of pure red-cell aplasia (PRCA) and malignant thymoma where the PRCA continued to persist despite computerised tomographic scan evidence of regression following radiotherapy and chemotherapy.

Haemophagocytosis in bone marrow aspirate--a review of the clinical course of 10 cases

The clinical course of 10 cases where marrow aspirate showed features of haemophagocytosis was reviewed. Eight of these had a fulminant clinical course characterized by high fever, constitutional symptoms, wasting, hepatosplenomegaly with liver dysfunction, sometimes lymphadenopathy, progressive pancytopenia and coagulopathy, like that described as 'malignant histiocytosis' in the past. The remaining 2 cases did not have this classical clinical syndrome. Among the former 8 cases, 4 of them had high-grade lymphoma, 3 of whom were confirmed to be peripheral T cell lymphoma. Three of the remaining 4 had suspicious lymphomatous infiltrate on marrow trephine. In every case an extensive search for viral etiology by serology was negative. The 2 cases which did not have fulminant clinical feature were found to have lymphoma of the diffuse large cell and Ki-1 anaplastic type, respectively. A review of the literature reveal that most cases with haemophagocytic syndrome have a fulminant clinical course and are peripheral T cell lymphoma, which generally has a poor prognosis. In our study, the 8 cases with the classical haemophagocytic syndrome had a median survival of 24 days and a long-term survival of 37.5% at 28 months. Prompt initiation of chemotherapy is a life-saving measure and the only chance of achieving a long-term survival in patients with haemophagocytic syndrome if the underlying lymphoma can be diagnosed early.

Detection of protein C or protein S deficiency in patients on warfarin therapy--a study of nine patients

This review studied 9 cases of young or middle-aged patients with protein C or protein S deficiency presenting with thrombotic events in the venous or arterial system. The clinical features were consistent with those described in the literature. Affected family members with similarly low levels were also detected in family studies, some of whom did not have any thrombotic history. Serial measurement of protein C, factor II and factor X at various International Normalization Ratio (INR) levels showed a correlation between suppression of these vitamin K dependent factors and degree of anticoagulation. Furthermore, there was a distinguishable difference in these indices (protein C level, protein C: factor II, protein C: factor X ratio) in warfarinized protein C deficient patients when compared with warfarinized patients who were not protein C deficient. This provides a means in diagnosing protein C deficiency even in warfarinized patients. Such a pattern was not found for protein S deficient patients, which may be due to the assay method used.

Use of low molecular weight heparin in the treatment of venous thrombosis in a patient with anti-thrombin III deficiency: a case report

This paper describes the use of a low molecular weight heparin (LMWH) in the treatment of a thrombotic episode in a patient with anti-thrombin III deficiency. Subcutaneous Fraxiparine, a low molecular weight heparin, was successfully used in the initial treatment of a second thrombotic episode in this patient with good results--no clot extension and an almost complete resolution of pulmonary emboli. This case demonstrates the advantages of using LMWH over conventional unfractionated heparin (UFH) which include ease of administration and the rapid achievement of optimal anticoagulation in conjunction with a diminished need for laboratory monitoring.

Main causes of pre-donation deferral of prospective blood donors in the Singapore Blood Transfusion Service

A retrospective study of the main causes of pre-donation deferral of prospective blood donors in the Singapore Blood Transfusion Service was carried out. Computerised records of all pre-donation deferrals from 1 January 1988 to 31 December 1991 were studied. A total of 278,401 pre-donation screening interviews were carried out during this period. Forty thousand one hundred and sixty-three or 14.4% of these transactions resulted in deferral of prospective blood donors either temporarily or permanently. Analysis of the deferrals showed that the top ten defined causes were: recent ingestion of medication; influenza; low haemoglobin level; a raised blood pressure; recent sexual exposure in high-risk activity; being underweight; Hepatitis B carrier status; recent history of measles, chickenpox or other infections; tattoos, ear-piercing or acupuncture in the preceding six months; and presenting for a subsequent donation too soon. To protect blood donors and recipients, stringent donor screening criteria are necessary. Modifying physical criteria could lower deferral rates but must be preceded by studies to ensure that donors do not suffer ill-effects. Increased public education on common causes of donor deferral may also lower deferral rates by allowing prospective donors to "pre-screen" themselves. However, one-to-one medical screening and appropriate counselling are still the best means for accepting or deferring blood donors in the Singapore setting.