Genome sequencing reveals underdiagnosis of primary ciliary dyskinesia in bronchiectasis

BACKGROUND

Bronchiectasis can result from infectious, genetic, immunological and allergic causes. 60-80% of cases are idiopathic, but a well-recognised genetic cause is the motile ciliopathy, primary ciliary dyskinesia (PCD). Diagnosis of PCD has management implications including addressing comorbidities, implementing genetic and fertility counselling and future access to PCD-specific treatments. Diagnostic testing can be complex; however, PCD genetic testing is moving rapidly from research into clinical diagnostics and would confirm the cause of bronchiectasis.

METHODS

This observational study used genetic data from severe bronchiectasis patients recruited to the UK 100,000 Genomes Project and patients referred for gene panel testing within a tertiary respiratory hospital. Patients referred for genetic testing due to clinical suspicion of PCD were excluded from both analyses. Data were accessed from the British Thoracic Society audit, to investigate whether motile ciliopathies are underdiagnosed in people with bronchiectasis in the UK.

RESULTS

Pathogenic or likely pathogenic variants were identified in motile ciliopathy genes in 17 (12%) out of 142 individuals by whole-genome sequencing. Similarly, in a single centre with access to pathological diagnostic facilities, 5-10% of patients received a PCD diagnosis by gene panel, often linked to normal/inconclusive nasal nitric oxide and cilia functional test results. In 4898 audited patients with bronchiectasis, <2% were tested for PCD and <1% received genetic testing.

CONCLUSIONS

PCD is underdiagnosed as a cause of bronchiectasis. Increased uptake of genetic testing may help to identify bronchiectasis due to motile ciliopathies and ensure appropriate management.

Depression, anxiety and stress among patients with diabetes in primary care: A cross-sectional study

BACKGROUND

The incidence of diabetes mellitus is ever increasing. Individuals with diabetes mellitus may have concurrent mental health disorders and are shown to have poorer disease outcomes. The objectives of this study were to determine the prevalence of depression, anxiety and stress (DAS) in diabetes patients aged 20 years or more in the primary care setting.

METHODS

This was a cross-sectional study involving the use of self-administered questionnaire conducted in eight primary care private and government clinics in Pulau Pinang and Melaka, Malaysia. The validated DASS-21 questionnaire was used as a screening tool for the symptoms of DAS. Prior permission was obtained from the patients and, clearance from ethical committee was obtained before the start of the study. Data analysis was done using SPSS statistical software.

RESULTS

A total of 320 patients with diabetes from eight centres were enrolled via convenience sampling. Sample size was calculated using the Kish's formula. The prevalence of DAS among patients with diabetes from our study was 26.6%, 40% and 19.4%, respectively. Depression was found to be significantly associated with marital status and family history of DAS; anxiety was significantly associated with monthly household income, presence of co-morbidities and family history of DAS; and stress was significantly associated with occupation and family history of DAS.

CONCLUSION

The prevalence of DAS was higher in patients with diabetes compared with the general community. We recommend to routinely screen all patients with diabetes using the DASS-21 questionnaire because it is easy to perform and inexpensive.

Dural sinus thrombosis owing to polycythaemia vera in a 12-year-old girl

Because of the rarity of dural sinus thrombosis in children with polycythaemia vera (PV), the options for diagnosis and treatment remain elusive. A 12-year-old girl was admitted with dural sinus thrombosis associated with PV, diagnosed by magnetic resonance venography. She was managed with interventional endovascular thrombolectomy and venoplasty, phlebotomy, hydroxyurea, low molecular weight heparin, and aspirin followed by warfarin. She made a good recovery without residual neurological deficit. This case highlights the importance of diagnosis and appropriate intervention with multi-modality treatments in patients with PV and thrombosis.

Carotid intima-media thickness is increased and related to arterial stiffening in patients with beta-thalassaemia major

An increased iron store has been linked to the risk of atherosclerosis. The carotid intima-media thickness (IMT), stiffness index, Young's elastic modulus (YEM), and augmentation index were determined in 20 patients with beta-thalassaemia major. Compared with controls, patients had greater IMT (P < 0.001), YEM (P = 0.005), and stiffness (P = 0.009) and augmentation (P = 0.03) indices. The odds ratio for increased IMT in patients was 39. Carotid IMT correlated with YEM (P = 0.036), stiffness index (P = 0.036) and augmentation index (P = 0.006). Multivariate analysis identified patient status (P < 0.001) as the only significant determinant of IMT. These findings suggest the possibility of premature atherosclerosis in beta-thalassaemia major patients.

Parental knowledge, attitudes and antibiotic use for acute upper respiratory tract infection in children attending a primary healthcare clinic in Malaysia

INTRODUCTION

A study was carried out in a primary healthcare clinic in the Hulu Langat district of Malaysia to assess the parental knowledge, attitudes and antibiotic use for common childhood acute upper respiratory tract infection (URTI).

METHODS

A cross-sectional study involving 421 parents, who were surveyed by using an interviewer-administered questionnaire, from April to June 2001.

RESULTS

Approximately 59 percent of parents from this study believed that weather was the main cause of acute URTI of their children, 13 percent thought it was due to food, and only about 27 percent said it was caused by germs. Nearly 68 percent, 69 percent and 76 percent of them believed that antibiotics was helpful in treating the common cold, cough and fever, respectively. 29 percent of parents who thought that their child with acute URTI needed antibiotics were not prescribed with any. On the other hand, 17 percent believed that antibiotics were unnecessary when prescribed. 28 percent of parents had requested for antibiotics, and 93 percent received what they requested for their child with acute URTI. About 31 percent of parents who did not request any antibiotics claimed that private general practitioners habitually prescribed antibiotics. The antibiotic compliance was poor with only 74 percent completing the entire course, with 85 percent of them stopping once they improved symptomatically. 15 percent of parents gave "leftover" antibiotics, 24 percent gave "shared" antibiotics, and 5.5 percent bought antibiotics for their child with acute URTI without consulting a doctor.

CONCLUSION

This study shows that parents often have inadequate knowledge and misconceptions on antibiotic use for acute URTI in children. Improved parental education may reduce unnecessary antibiotic prescription and antimicrobial resistance in the community.

Management of type 2 diabetes mellitus: is it in accordance with the guidelines?

A cross-sectional study was conducted among 517 patients with diabetes mellitus at all health centres in Melaka Tengah District to examine whether these patients and their associated cardiovascular risk factors were managed according to current guidelines. All patients had Type 2 diabetes mellitus with mean age of 57.9 +/- 10.5 years and the mean duration of diabetes was 7.2 +/- 6.0 years. The glycaemic control was poor with 53.6% of the patients having HbAlc above 8% (mean = 8.5%) and 24% of them had microalbuminuria. Among these patients with poor glycaemic control, about 47.6% of them were on monotherapy. Three hundred and fifty (67.7%) patients had hypertension but only 11 (3.1%) achieved target blood pressure of less than 130/80 mmHg. Only 18.3% of the diabetics with hypertension were prescribed angiotensin converting enzyme inhibitors and 0.3% with angiotensin receptor blockers. Nearly two-third of them had low-density lipoprotein cholesterol greater than 2.6 mmol/l (mean = 3.4 mmol/l) but only 6.8% were prescribed lipid-lowering agents. Aspirin was prescribed to 8.2% of diabetics aged above 40 years. Sixteen percent of the patients smoked, 53% did not do any exercise, and the mean BMI was 26.8 kg/mn. The management of diabetes mellitus and its associated cardiovascular risk factors was suboptimal on the basis of current clinical guidelines. A greater effort in educating doctors in the health centres about these management and adherence to the guidelines is important in reducing patients' risk of cardiovascular disease and its associated morbidity and mortality.

Primary care doctors' perceptions towards evidence-based medicine in Melaka State: a questionnaire study

A cross sectional study using a self-administered questionnaire to determine the perceptions of primary care doctors towards evidence-based medicine (EBM) was conclucted in Melaka state. About 78% of the primary care doctors were aware of EBM and agreed it could improve patient care. Only 6.7% of them had ever conducted a Medline literature search. They had a low level of awareness of review publications and databases relevant to EBM; only about 33% of them were aware of the Cochrane Database of Systemic Reviews. Over half of the respondents had at least some understanding of the technical terms used in EBM. Ninety percent of the respondents had Internet access and the majority of them used it at home. The main barriers to practicing EBM were lack of personal time and lack of Internet access in the primary care clinics.

Type 2 diabetes mellitus with hypertension at primary healthcare level in Malaysia: are they managed according to guidelines?

INTRODUCTION

A study was conducted at primary healthcare level in the Melaka Tengah district of Malaysia to determine whether hypertension in patients with type 2 diabetes mellitus were managed according to guidelines.

METHODS

A cross-sectional study involving 517 patients with diabetes mellitus from August to October 2003 was performed.

RESULTS

All the subjects had type 2 diabetes mellitus. 350 (67.7 percent) patients had hypertension and about 25.7 percent of them were associated with microalbuminuria. The Malay ethnic group form the majority (54.6 percent), followed by Chinese (37.7 percent) and Indian (7.4 percent). Only 11 (3.1 percent) patients with type 2 diabetes mellitus and hypertension achieved the target blood pressure of less than 130/80 mmHg. For those who had not achieved the target goal, 39.5 percent of them were not on any antihypertensive drugs. 38.6 percent were on monotherapy and only 21.8 percent were on two or more antihypertensive drugs. Metoprolol was the most commonly used antihypertensive drug (22.4 percent), followed by Nifedipine (16.2 percent) and Prazosin (13.5 percent). Only 18.3 percent of patients with type 2 diabetes mellitus and hypertension were prescribed with angiotensin converting enzyme (ACE) inhibitors and 0.3 percent with angiotensin receptor blockers. For patients with type 2 diabetes mellitus, hypertension and microalbuminuria, only 14.1 percent of them were prescribed with ACE inhibitors.

CONCLUSION

A significant proportion of patients with type 2 diabetes mellitus had associated hypertension but they were not managed optimally according to guidelines. More intensive management of hypertension among patients with diabetes is essential to reduce the morbidity and mortality at primary healthcare level.

Primitive small round cell tumour of the adrenal gland presenting with fever of unknown origin and t(12;22)(q13;q12) cytogenetic finding

This report describes a left adrenal tumour in a 16 year old Chinese girl who presented with fever of unknown origin. The histological and ultrastructural features of the adrenal tumour were those of a primitive small round cell tumour with neuroendocrine differentiation. Cytogenetic analysis of cultured tumour cells showed a reciprocal translocation t(12;22)(q13;q12). This is the first example of such a tumour being reported in the adrenal gland. The adrenal tumour was also the cause of the fever, which subsided after the removal of the tumour.

Human endothelin converting enzyme-2 (ECE2): characterization of mRNA species and chromosomal localization

Generation of the functionally pleiotropic members of the endothelin vasoactive peptide family is critically catalyzed by unique type II metalloproteases, termed endothelin converting enzymes (ECE). Isolation of human ECE-2 (EC 3.4.24.71) cDNAs revealed deduced open reading frames of 787 and 765 amino acids with approximately 60% identity with human ECE-1. Characterization of mRNA variants revealed mRNA structural diversity at the 5'-terminus. Two mRNA species exist containing distinct first and second exons. Furthermore, in one of these species, an in-frame deletion of the intracytoplasmic domain removed 29 amino acids. Because of the previously reported human genetic diseases ascribed to germline mutations of member genes of the endothelin family, ECE2 was localized in human chromosomes with fluorescence in situ hybridization and radiation hybrid mapping to 3q28-q29 and SHGC-20171/D3S1571, respectively.

Solid-cystic papillary tumor of the pancreas in children

Solid-cystic papillary tumor (SCPT) of the pancreas is a rare neoplasm in children. The current study attempted to estimate the incidence and possible pathological origin of the tumor. Clinicopathologic features of the children under the age of 16 years with pancreatic tumors managed in a single institution between January 1993 and November 1999 were reviewed. Representative blocks of SCPT specimens were immunostained for neuron-specific enolase (NSE) chromogrannin, synaptophysin, insulin, glucagon, somatostatin, and gastrin. There were three SCPTs, two pancreatic endocrine tumors, and one acinar cell carcinoma during the study period. The estimated yearly incidence in the referral area of 2 million population is about 0.01 pediatric SCPT per year per 100,000 population. The children underwent surgical removal of the tumors. Postoperatively, they were followed up for 6 months to 4 years and were well. Immunostaining for NSE, chromogranin, synaptophysin, insulin, somatostatin, and gastrin was negative in all cases. SCPT may thus be the most common pancreatic tumor in the Asian pediatric population. The pathological origin of the tumor remains unclear and requires further investigations.

Ewing sarcoma of the small intestine

This report describes a rare case of Ewing sarcoma (ES) of the small intestine. The patient was a 9-year-old girl with progressive abdominal distension. Computed tomography showed a large mass in the small bowel. Histopathologic examination of the resected tumor showed ES with typical histologic, immunohistochemical, and ultrastructural features. The tumor recurred in the pelvic cavity 18 months after the original surgery. Molecular study of the recurrent tumor confirmed a diagnostic EWS-FLI1 gene fusion. This patient illustrates the unique occurrence of ES in the small intestine.

Characterization of additional genetic events in childhood acute lymphoblastic leukemia with TEL/AML1 gene fusion: a molecular cytogenetics study

TEL/AML1 gene fusion that results from a cryptic t(12;21) is the most common genetic aberration in childhood B-lineage acute lymphoblastic leukemia (ALL). While the translocation may initiate the leukemic process, critical secondary genetic events are currently believed to be pivotal for leukemogenesis. We investigated 12 cases of childhood ALL with TEL/AML1 gene fusion by fluorescence in situ hybridization (FISH) and comparative genomic hybridization (CGH) and documented additional or secondary genetic changes in seven patients (58%). Three patients showed extra copies of chromosome 21 including a case in which the trisomy 21 (+21) clone was distinct from the one harboring TEL/AML1 gene fusion. Interestingly, one patient without +21 showed amplification of the AML1 gene on chromosome 21q, supporting the contention that AML1 amplification may be an important additional genetic event. Gene expression study by semi-quantitative reverse-transcription polymerase chain reaction (RT-PCR) in two of these four patients showed an increase in AML1 transcripts that paralleled the increase in gene copy number. Deletion of the normal TEL allele was detected in two patients, with one of them showing loss of chromosome 12 together with duplication of the der(12)t(12;21). Finally, one patient showed duplication of the fusion signal. Our findings confirm that additional or secondary genetic changes including AML1 amplification are commonly encountered in childhood ALL with TEL/AML1 gene fusion, which are envisaged to play significant roles in disease progression.

Fusion of two novel genes, RBM15 and MKL1, in the t(1;22)(p13;q13) of acute megakaryoblastic leukemia

t(1;22) is the principal translocation of acute megakaryoblastic leukemias. Here we show this chromosomal rearrangement to result in the fusion of two novel genes, RNA-binding motif protein-15 (RBM15), an RNA recognition motif-encoding gene with homology to Drosophila spen, and Megakaryoblastic Leukemia-1 (MKL1), a gene encoding an SAP (SAF-A/B, Acinus and PIAS) DNA-binding domain.

Successful mismatched sibling cord blood transplant in Hb Bart's disease

A 20-month-old girl with Hb Bart's disease, who had survived neonatal complications, underwent HLA-DR antigen mismatched sibling cord blood transplantation successfully. Immune thrombocytopenia, which occurred around 2.5 months after transplant, responded to intravenous gamma-globulin. The fetal hemoglobin level rose to a peak of 52.3% on day +69 post transplant and declined gradually during the following year. Ten percent of hemoglobin Bart's was detected 2 months after transplant and this reflects the alpha-thalassemia trait of the donor.

DNA elements of the type 1 adenylyl cyclase gene locus enhance reporter gene expression in neurons and pinealocytes

The Ca2+-stimulated type 1 adenylyl cyclase (AC1) contributes to several forms of synaptic plasticity and is the only known neurospecific adenylyl cyclase. Furthermore, the protein and mRNA levels of AC1 undergo a circadian oscillation in the pineal gland, and AC1 may play a pivotal role in regulating nocturnal melatonin synthesis. To better understand the expression of AC1, we isolated mouse genomic DNA clones of AC1. The transcription and translation start regions of mouse AC1 share extensive homologies with the bovine counterpart. The upstream proximal region has potential binding sites for transcription factors, including the steroid receptor family, the E-box factors, and Sp1. A 280-bp fragment that contains the transcription start site directed reporter gene expression in cultured cortical neurons and pinealocytes functioning as a basal neuro- and pineal-directed promoter. Interestingly, pinealocyte expression of the reporter gene was inhibited by increases in cAMP. This cAMP sensitivity may explain why AC1 mRNA in the pineal is low at night when cAMP is elevated and high during the day when cAMP signals drop. An adjacent 330-bp fragment interacted specifically with nuclear factor(s) that we designate binary E-box factor (BEF). Methylation interference and DNase I footprinting identified the BEF-binding site sequence as 5'-CCAAGGTCACGTGGC-3'. When linked to the basal tissue-directed promoter, this 15-bp sequence further enhanced reporter expression in neurons and pinealocytes. We propose that this 15-bp sequence may contribute to increased expression of AC1 in neurons and pinealocytes relative to other cells.

Disruption of the type III adenylyl cyclase gene leads to peripheral and behavioral anosmia in transgenic mice

Cyclic nucleotide-gated ion channels in olfactory sensory neurons (OSNs) are hypothesized to play a critical role in olfaction. However, it has not been demonstrated that the cAMP signaling is required for olfactory-based behavioral responses, and the contributions of specific adenylyl cyclases to olfaction have not been defined. Here, we report the presence of adenylyl cyclases 2, 3, and 4 in olfactory cilia. To evaluate the role of AC3 in olfactory responses, we disrupted the gene for AC3 in mice. Interestingly, electroolfactogram (EOG) responses stimulated by either cAMP- or inositol 1,4,5-triphosphate- (IP3-) inducing odorants were completely ablated in AC3 mutants, despite the presence of AC2 and AC4 in olfactory cilia. Furthermore, AC3 mutants failed several olfaction-based behavioral tests, indicating that AC3 and cAMP signaling are critical for olfactory-dependent behavior.

Cytotoxic chemotherapy has minimal direct effect on gastric myoelectric activity in children with 5HT(3) antagonist prophylaxis

BACKGROUND

Cancer patients receiving cytotoxic chemotherapy frequently develop nausea and vomiting. The direct effect of chemotherapy on gastric pacemaker is not clear. The objective of this study was to assess the direct interference of gastric electrical activity by chemotherapeutic agents as a possible cause of vomiting using electrogastrography (EGG).

PROCEDURE

Fasting surface EGGs were recorded in 24 children with malignancy and 24 age-matched controls. All oncology patients received the intravenous prophylatic ondansetron. According to the known emetic potential of the medications they received, the children were divided into mild, moderate, and severe groups. The EGG recordings of oncology patients were segmented into prechemotherapy period, chemotherapy period, and emetic period. The EGG data from each period were collected and analyzed (paired t-test and Mann-Whitney U test).

RESULTS

There were 24 children (M:F ratio: 14:10), with a mean age of 9.6 years. Eight children vomited during the course of recording (0/3 from the mild group, 2/6 from the moderate group, and 6/15 from the severe group). The average duration of intravenous medication infusion was 7.8 hr (range 2 min to 24 hr). There was no difference between the EGG of normal control and the prechemotherapy EGG of the oncology patients. No difference was detected between the EGG data from the prechemotherapy period and the chemotherapy period. A statistically significant increase in tachygastria was detected in emetic periods (28 episodes, mean duration 5 min; P = 0.01).

CONCLUSIONS

Insignificant EGG changes during chemotherapy suggest that chemotherapy has a minimal direct effect on gastric pacemaker. Tachygastria seemed to be a secondary effect of vomiting rather than the cause of it. These preliminary findings suggest that efforts to modify gastric electrical rhythm as a means of management of chemotherapy-induced vomiting may be futile. Further studies to identify factors responsible for vomiting are warranted.

Cytogenetic characterization of childhood hepatoblastoma

We describe the cytogenetic abnormalities in two cases of childhood hepatoblastoma. The first case was of fetal histology with squamous metaplasia, and cytogenetic study showed an add(5)(q31). Although an association between hepatoblastoma and familial adenomatous polyposis is recognized, the breakpoint in this case is distal to 5q21 and most probably does not involve the APC gene at that location. The second case was of macrotrabecular histology, and cytogenetic study showed an unbalanced translocation in the form of der(4)t(1;4)(q12;q34) in a hyperdiploid clone. Including our case, der(4)t(1;4)(q12;q34) has been recognized in four cases of hepatoblastoma, and it may be the first recurrent translocation in this tumor. Understanding the molecular mechanism and clinical significance of this translocation awaits analysis of more cases.

Complex cytogenetic abnormalities in T-lymphoblastic lymphoma: resolution by spectral karyotyping

We describe a case of T-lymphoblastic lymphoma (T-LBL) in a 13-year-old boy in which conventional cytogenetic analysis of lymph node tissue showed complex karyotypic aberrations including add(1p), add(2q), and multiple chromosomal deletions involving 5q, 7p, 7q, 13q, and 16q. Analysis by spectral karyotyping (SKY) refined add(1p) to a paracentric inversion of 1p, and add(2q) to an unbalanced translocation between chromosomes 2 and 4. The chromosomal deletions were simple deletions except del(5q), which was confirmed by SKY to be a cryptic unbalanced translocation between chromosomes 5 and 18. The present report illustrates that SKY technology is useful in identifying subtle translocations and resolving complex karyotypic aberrations in neoplastic disorders.

Analysis of MLL-derived transcripts in infant acute monocytic leukemia with a complex translocation (1;11;4)(q21;q23;p16)

It has been proposed, on the basis of cytogenetic studies and molecular analysis of MLL-derived transcripts in acute leukemia with 11q23 rearrangement, that only one fusion gene transcript present on the der(11) chromosome is critical for leukemogenesis. This view is challenged by a recent observation in a case of leukemia with a complex translocation that results in MLL being fused in-frame to two different partner genes. We investigated a case of infant monocytic leukemia with a complex translocation, (1;11;4)(q21;q23;p16). Molecular studies revealed MLL rearrangement by both fluorescence in situ hybridization and Southern blot analysis, and MLL/AF1q, but not the reciprocal message (i.e., AF1q/MLL), was amplified by polymerase chain reaction. Sequence analysis of MLL/AF1q revealed an in-frame fusion between MLL exon 6 and the breakpoint located six bases upstream of the ATG start site for AF1q. Our data suggest that only one form of MLL fusion gene is implicated in leukemogenesis in our case to t(1;11;4).

Refractory anemia with ringed sideroblasts in children: two diseases with a similar phenotype?

Three pediatric patients with refractory anemia with ringed sideroblasts (RARS) are presented. Bone marrow aspirates were examined using Romanowsky and Prussian blue iron stains in all three patients, and electron microscopic analysis was performed in one patient. All three patients had cytogenetic analysis of the bone marrow. Other studies included analysis of serum iron, total iron-binding capacity, ferritin, copper, vitamins B6 and B12, and folate levels. Antibody titers to Parvovirus, HIV, and other viruses were measured. The patients had contrasting clinical courses. Patients 1 and 2 had dysplastic hematopoietic features and cytogenetic findings (with either partial or one allele loss of chromosome 7), suggestive of myelodysplastic syndrome. Patient 1 experienced acute myeloid leukemia (AML) and had a good response to AML-directed therapy. Patient 2 had prolonged cytopenias and underwent bone marrow transplantation (BMT). Patient 3 had features suggestive of refractory anemia associated with mitochondrial cytopathy, including normal cytogenetics with pronounced vacuolization of marrow precursors. His anemia regressed spontaneously a few months after diagnosis. These patients represent two subgroups of pediatric RARS. Patients with the myelodysplastic syndrome (MDS) type may progress to cytopenias or leukemia and may require aggressive therapy; the type is characterized by clonal cytogenetic findings. The non-MDS type, which may relate to mitochondrial cytopathy, often shows spontaneous regression and requires only supportive treatment; it has normal cytogenetic findings.

Metanephric adenofibroma: report of a case and review of the literature

The recent recognition of a variety of pediatric renal tumors of different biologic behavior places an ever-increasing demand on the surgical pathologist for an accurate diagnosis. Although metanephric adenofibroma is one of the rarest benign renal tumors, the clinical importance of correctly diagnosing it cannot be overemphasized because it can potentially be mistaken as Wilms' tumor. We describe the clinical, radiologic, and pathologic features of a case of metanephric adenofibroma and discuss its differential diagnosis. The neoplasm was composed of two discrete components: a major fibroblastic element and a minor immature epithelial element. The latter formed a small nodule beneath the renal capsule, which could barely be detected by magnetic resonance imaging. This subcapsular nodule, however, was slightly soft and tan and was distinctly different from the white, whorled cut surface of the main tumor. It was formed by closely packed small immature epithelial cells in a slightly edematous background, which was histologically identical to metanephric adenoma and closely resembled epithelial Wilms' tumor. Unlike Wilms' tumor, however, the epithelial cells were very bland with no mitoses. The main bulk of the tumor was formed by spindle fibroblastic cells that were cytologically similar to the spindle cells in congenital mesoblastic nephroma. The tumor, however, was well demarcated without the irregular infiltrating edges of congenital mesoblastic nephroma. In contrast to the randomly distributed epithelial element throughout the stromal component in previous reported cases of metanephric adenofibroma, our finding of the exceedingly small and discrete epithelial component expands the known histologic spectrum of the disease. In addition, the presence of such minute epithelial nodule underscores the importance of diligent pathologic examination and careful sampling of tissue for histologic examination.

Near-haploid common acute lymphoblastic leukaemia of childhood with a second hyperdiploid line: a DNA ploidy and fluorescence in-situ hybridization study

Near-haploidy is a rare cytogenetic finding in childhood acute lymphoblastic leukaemia (ALL) and is associated with a poor prognosis. A second hyperdiploid line, occurring presumably by endoreduplication of the near-haploid stemline, is often observed. We present a case of common ALL in relapse characterized morphologically by a dual population of small and large lymphoblasts. Cytogenetic analysis supplemented with fluorescence in-situ hybridization (FISH) studies localized near-haploidy and hyperdiploidy to the small and large blast population respectively. DNA ploidy determination confirmed two abnormal clones with near-haploidy as the predominant one. A novel t(9;12)(q11;q13) was present in the near-haploid clone and was duplicated in the hyperdiploid clone. This finding identified cells bearing near-haploidy to be the clonogenic population following malignant transformation and confirmed endoreduplication as the mechanism for the presence of associated hyperdiploidy.

End tidal carbon monoxide concentration in childhood haemolytic disorders

OBJECTIVES

Endogenous carbon monoxide (CO) is produced mainly by heme catabolism. As CO is excreted solely by the lung, a simple technique for measuring the end tidal carbon monoxide (ETCO) level was assessed as a method for screening for haemolytic disease in children.

METHODS

Two end expiratory breath samples were collected from normal children and from children with haemolytic disease using a one way valve connector between a mouth piece and an anaesthetic bag. The samples were analysed by gas chromatography for CO and carbon for dioxide (CO2). The CO2 value was used to normalise the CO value to an alveolar concentration. Carboxyhaemoglobin (HbCO) also was measured in the patient group for correlation analysis with ETCO.

RESULTS

A total of 21 children with beta thalassaemia major, 15 children with other haemolytic diseases (hereditary spherocytosis n=8, haemoglobin H disease n=3 and thalassaemia intermedia n=4) and 23 normal children were studied. The mean ETCO concentrations in the three groups were 3.21 p.p.m., 7.41 p.p.m. and 0.69 p.p.m., respectively, which were significantly different from each other (P<0.0001). There was a significant correlation between ETCO and HbCO in the patient groups (r=0.85; P<0.0001).

CONCLUSIONS

The end expiratory breath collection device is a simple and feasible sample collection method. The results confirm that ETCO can be used clinically to distinguish children with a variety of haemolytic disorders from normal subjects.

Phosphorylation and inhibition of olfactory adenylyl cyclase by CaM kinase II in Neurons: a mechanism for attenuation of olfactory signals

Acute desensitization of olfactory signaling is a critical property of the olfactory system that allows animals to detect and respond to odorants. Correspondingly, an important feature of odorant-stimulated cAMP increases is their transient nature, a phenomenon that may be attributable to the unique regulatory properties of the olfactory adenylyl cyclase (AC3). AC3 is stimulated by receptor activation and inhibited by Ca2+ through Ca2+/calmodulin kinase II (CaMKII) phosphorylation at Ser-1076. Since odorant-stimulated cAMP increases are accompanied by elevated intracellular Ca2+, CaMKII inhibition of AC3 may contribute to termination of olfactory signaling. To test this hypothesis, we generated a polyclonal antibody specific for AC3 phosphorylated at Ser-1076. A brief exposure of mouse olfactory cilia or primary olfactory neurons to odorants stimulated phosphorylation of AC3 at Ser-1076. This phosphorylation was blocked by inhibitors of CaMKII, which also ablated cAMP decreases associated with odorant-stimulated cAMP transients. These data define a novel mechanism for termination of olfactory signaling that may be important in olfactory responses.

Enhanced hippocampal CA1 LTP but normal spatial learning in inositol 1,4,5-trisphosphate 3-kinase(A)-deficient mice

To define the physiological role of IP(3)3-kinase(A) in vivo, we have generated a mouse strain with a null mutation of the IP(3)3-kinase(A) locus by gene targeting. Homozygous mutant mice were fully viable, fertile, apparently normal, and did not show any morphological anomaly in brain sections. In the mutant brain, the IP4 level was significantly decreased whereas the IP3 level did not change, demonstrating a major role of IP(3)3-kinase(A) in the generation of IP4. Nevertheless, no significant difference was detected in the hippocampal neuronal cells of the wild-type and the mutant mice in the kinetics of Ca2+ regulation after glutamate stimulation. Electrophysiological analyses carried out in hippocampal slices showed that the mutation significantly enhanced the LTP in the hippocampal CA1 region, but had no effect on the LTP in dentate gyrus (DG). No difference was noted, however, between the mutant and the wild-type mice in the Morris water maze task. Our results indicate that IP(3)3-kinase(A) may play an important role in the regulation of LTP in hippocampal CA1 region through the generation of IP4, but the enhanced LTP in the hippocampal CA1 does not affect spatial learning and memory.

Sibling HLA-matched cord blood transplant for beta-thalassemia: report of two cases, expression of fetal hemoglobin, and review of the literature

PURPOSE

A program of cord blood stem cell (CBSC) transplants for patients with beta-thalassemia major was initiated in conjunction with the prenatal diagnostic service in 1994. Two patients who received HLA-matched related CBSC transplants with posttransplant fetal hemoglobin (HbF) expression are described and the literature is reviewed.

PATIENTS AND METHODS

After screening 12 pregnancies, matched sibling CBSC transplants were performed for 2 girls with beta-thalassemia major when they were 3.8 and 2.2 years old, respectively. Their HbF was assayed serially.

RESULTS

The nucleated cell counts/kg were 11.4 x 10(7) and 6.2 x 10(7), which engrafted on days 19 and 24, respectively. The children are now transfusion-independent at 3 years and 1.2 years posttransplant. Their HbF levels showed a rapid rise posttransplant and reached peak levels of 37.2% and 42.2% on day 83 and day 88, respectively. The HbF levels declined to 1.0% and 3.8% on day 581 and day 305, respectively. Nine other sibling CBSC transplants for thalassemias have been reported with an engraftment rate of approximately 50%. Graft rejection was related to insufficient CBSC number in one.

CONCLUSIONS

HbF levels in patients with beta-thalassemia major after CBSC transplants could be influenced by many factors, including reactivation of HbF synthesis, intrinsic rate of Hb switching of CBSC, and mixed chimerism.

Hippocampal neurotoxicity of Delta9-tetrahydrocannabinol

Marijuana consumption elicits diverse physiological and psychological effects in humans, including memory loss. Here we report that Delta9-tetrahydrocannabinol (THC), the major psychoactive component of marijuana, is toxic for hippocampal neurons. Treatment of cultured neurons or hippocampal slices with THC caused shrinkage of neuronal cell bodies and nuclei as well as genomic DNA strand breaks, hallmarks of neuronal apoptosis. Neuron death induced by THC was inhibited by nonsteroidal anti-inflammatory drugs, including indomethacin and aspirin, as well as vitamin E and other antioxidants. Furthermore, treatment of neurons with THC stimulated a significant increase in the release of arachidonic acid. We hypothesize that THC neurotoxicity is attributable to activation of the prostanoid synthesis pathway and generation of free radicals by cyclooxygenase. These data suggest that some of the memory deficits caused by cannabinoids may be caused by THC neurotoxicity.

Transient erythroblastopenia of childhood associated with transient neurologic deficit: report of a case and review of the literature

OBJECTIVE

Patients with transient erythroblastopenia of childhood (TEC) may also have a transient neurologic disorder. We present a case history and propose a mechanism for this syndrome. PATIENT AND METHODOLOGY: We describe a 20-month-old girl with TEC and transient hemiparesis. Records from the period January 1993 through December 1994 were reviewed to identify other patients with TEC and to determine whether neurologic deficits were noted in these cases.

RESULTS

Of seven patients diagnosed with TEC over a 2-year period, only one had a neurologic deficit. This child's hemiparesis resolved within 24 h after the appearance of her symptoms. Her TEC resolved within 4 weeks, without long-term sequelae. Our experience and review of the literature suggest that focal neurologic deficits in TEC patients are uncommon, transient, lack long-term sequelae, and usually resolve prior to hematologic recovery.

CONCLUSIONS

Previous reports suggested that the anaemia resulting from TEC might induce neurologic deficits. We suggest an alternative mechanism in which viral infection triggers a host immune response that independently leads to both TEC and neurologic abnormalities. Future studies should address the role of viral infection in TEC patients with focal neuropathies.

Multidisciplinary management of osteosarcoma: experience in Hong Kong

All pediatric osteosarcomas treated in our hospital between 1985 and 1995 were reviewed. There were 26 patients, 15 males and 11 females, aged 20 or less at diagnosis. All had limb primaries. Nineteen patients had localized disease and seven presented with metastases. Intensive multiagent chemotherapy was given both pre- and postoperatively. Most patients were treated with the Rosen T10 regimen or its modifications. Only one patient had limb salvage surgery; all others had amputation. With a median follow-up of 74 months, the 5-year disease-free survival among patients with localized disease was 65.2%. Being female and having a high 6-hour postinfusion methotrexate level with a median level greater than 700 mumol/L were good prognostic factors. Three of the seven patients with metastatic disease were alive at 21, 26, and 140 months after diagnosis. All of them had lung secondaries. Survival rates achieved in our center were comparable to those reported in literature. However, our amputation rate was high and further development in expertise for limb salvage treatment is a goal.

Primary human herpes virus 6 infection transmitted from donor to recipient through bone marrow infusion

An 8.5-month-old boy with Wiskott-Aldrich syndrome received a sibling matched bone marrow transplant from his healthy non-identical twin brother. The donor had primary human herpes virus 6 (HHV-6) infection around the time of bone marrow donation. The recipient had hepatitis in the first week and then developed fever and rash on day 18. Skin biopsy was shown to have HHV-6 antigen and his peripheral blood leukocytes were HHV-6 DNA positive. He engrafted on day 18 but the ANC dropped from 5.5 x 10(9)/l (day 23) to 0.48 x 10(9)/l (day 34) with persistent HHV-6 DNAemia. Bone marrow on day 35 was positive for HHV-6 DNA. He was treated with G-CSF and ganciclovir with good response. He later had pneumonitis which was treated empirically with foscarnet, ceftazidime and clarithromycin.

Prevention of beta-thalassemia major by antenatal screening in Hong Kong

The thalassemias are common in Hong Kong. One of the severe forms, beta-thalassemia major, has been preventable locally by antenatal screening since 1983. Yet new patients are still being diagnosed. In this retrospective study, 34 children with severe beta-thalassemia syndromes were diagnosed in two major public hospitals between 1990 and 1996. They included one pair of identical twins and two pairs of siblings. Twenty-seven (79%) had homozygous beta-thalassemia and seven (21%) had beta E thalassemia. All but four (12%) were transfusion dependent. Fifty-five (89%) parents had been evaluated for their thalassemia status. Forty-eight had beta-thalassemia traits and seven were hemoglobin E carriers. The reasons for the birth of these children with severe beta-thalassemia syndromes were (1) late or no antenatal visit (n = 8, 24.2%), including three cross-border deliveries in which the pregnant mothers came from mainland China to Hong Kong for confinement, (2) lack of maternal screening (n = 13, 39.4%), (3) lack of paternal screening (n = 7, 21.2%), (4) parental refusal (n = 3, 9.1%), and (5) unknown (n = 2, 6.1%). These findings suggest that several factors undermine the effectiveness of antenatal screening for prevention of thalassemias. Many medical practitioners and the general public are still not aware of the screening procedures. The migration of population from mainland China to Hong Kong may result in the birth of many more children with beta-thalassemia major.

Myelodysplastic syndrome in children: differentiation from acute myeloid leukemia with a low blast count

To evaluate diagnostic criteria, disease characteristics, and the clinical course of pediatric myelodysplastic syndrome (MDS), we reviewed 327 consecutive cases diagnosed with de novo acute myeloid leukemia (AML) or MDS at St Jude Children's Research Hospital between February 1980 and January 1993. Among 49 cases with <30% marrow blasts (consistent with FAB criteria and common diagnostic practice for MDS), eight had karyotypes associated with de novo AML (four with t(8;21)(q22;q22) and one each with inv(16)(p13q22), t(11;17)(q23;q21), t(9;11)(p22;q13), and i(1)(ql0)). We termed these cases AML with a low blast count (AML-LBC) and compared their clinical and morphologic features with those of the remaining 41 cases. AML-LBC cases had little or no hematopoietic dysplasia. MDS cases consisted of refractory anemia (RA, n=6), RA with ring sideroblasts (n=2), RA with excess blasts (RAEB, n=4), RAEB in transformation (n=14), and chronic myelomonocytic leukemia (n=15). Most had moderate/severe or multilineage hematopoietic dysplasia, with significantly higher dysplasia scores than AML-LBC cases (P=0.007). Only 30% of patients with MDS achieved complete remission (CR) after two cycles of AML-directed therapy, compared with 88% of patients with AML-LBC (P=0.0001); MDS patients tended to experience prolonged severe cytopenias with chemotherapy. The 4-year survival for MDS patients was 23% +/- 7% (s.e.), vs 50% +/- 18% (s.e.) for AML-LBC (P=0.048). AML-LBC patients frequently had chloromas; none were seen in MDS patients. We conclude that the 30% blast threshold is ineffective for separation of AML and MDS in pediatric patients, and that genetic data should be included in this decision process. AML-LBC, defined by <30% blasts in bone marrow and cyto- (or molecular) genetic abnormalities associated with de novo AML, and characterized by absent or mild marrow dysplasia, is biologically and clinically distinct from MDS and should be treated as de novo AML. Outcome in pediatric MDS remains poor, and new treatment strategies are needed for these patients.

Infection complicating percutaneous liver biopsy in liver transplant recipients

There is controversy about the frequency of and risk factors for infectious complications of percutaneous liver biopsy in liver transplant recipients. The aim of this study was to identify the incidence and nature of complications associated with liver biopsy after orthotopic liver transplantation (OLT), with particular emphasis on infection. The medical records of all patients undergoing OLT between January 1990 and August 1994 were reviewed retrospectively to identify complications requiring hospitalization within one week of percutaneous liver biopsy. The nature and severity of complications were recorded and possible risk factors for infectious complications were examined. One hundred ninety-eight patients underwent 1,136 percutaneous liver biopsies. There were eleven complications (0.96%), including as follows: 7 infections, 3 bleeding episodes, and 1 vasovagal reaction. Infections after percutaneous liver biopsy included fever and bacteremia (n = 6), and fever without bacteremia (n = 1). All infections developed only in patients with underlying biliary tract abnormalities; the frequency of infection was higher (9.8%) in patients with choledochojejunostomy when compared with those with choledochocholedochostomy (1.4%). Bacteremia was more likely caused by skin flora in patients with choledochocholedochostomy (CDC) and by enteric bacteria in patients with choledochojejunostomy (CDJ). All infections were treated successfully with parenteral antibiotics. We conclude that biliary tract abnormalities are the primary risk factors for infection after percutaneous liver biopsy, although the risk is higher in patients with CDJ than with CDC. These data support the use of antibiotic prophylaxis before percutaneous liver biopsy in OLT recipients with biliary tract abnormalities.

The ageing worker

In Singapore, the age for retirement has increased from 55 years to 60 years, and will eventually reach 67 years. At the same time, the proportion of workers aged above 45 years will continue to increase. The World Health Organisation has reported that in 1980, 32% of the working population were older than 45 years of age in countries of the Organisation for Economic Co-operation and Development (OECD). This proportion is expected to rise to 35.5% in the year 2000 and 41.3% in the year 2055. What are the implications of the emergence of an ageing workforce? This population represents a special group of individuals in the workforce that have special health, occupational and environmental needs. On the one hand, they have the problem of a reduction in physical work capacity, decreased adaptability, and a generally lower health status. On the other, ageing workers are more experienced and have greater expertise. They are also usually more motivated and may generally have a more positive attitude when compared with younger workers. Society, as well as health care professionals, needs to respond to this issue of an ageing workforce. The response should be three pronged. Firstly, prevention of the premature decline of physical capacities and adaptability of the worker could be addressed by health promotion and continuing job training. Secondly, some measures for adjusting work demands in accordance with functional capacities of the individual are needed. Thirdly, employers and fellow workers should be educated on the strengths of the ageing worker, and the capacity of such workers to continue contributing because of their experience, motivation and skills. If implemented, these measures would ensure a path towards productive ageing. The end results would be that ageing workers would have their functional capacity maintained, the concept of "age-adjusted workload" would be a reality, and ageing workers would not be discriminated against, but instead have their contributions to society maximised.

Clinical presentation, hematologic features and treatment outcome of childhood acute lymphoblastic leukemia: a review of 73 cases in Hong Kong

Seventy-three consecutive cases of childhood acute lymphoblastic leukemia (ALL) diagnosed and managed in Queen Mary Hospital over a 10-year period from 1985 to 1994 were retrospectively analysed for their presenting features and treatment outcome. The 48 boys and 25 girls ranged in age from 0.4 to 14.2 years (median: 4.3 years). Bone and joint pain was a relatively common presenting feature besides fever, hepatosplenomegaly and lymphadenopathy. Immunophenotyping of blast cells showed: 51 B-cell precursor ALL, one B-ALL, 10 T-ALL and three myeloid-antigen positive ALL. Eight cases were unclassified since immunophenotyping had not been performed. Out of the 73 patients, treatment outcome was analysed in 20 cases treated with UKALL-VIII regimen and 28 cases treated with either the UKALL-XI regimen or the Hong Kong Children Cancer Study Group (HKCCSG) protocol which was modelled upon UKALL-XI. Although complete remission rates were similar between the two groups, patients treated with the former regimen that was less intensified suffered more relapses than the latter (56 per cent versus 21 per cent, P = 0.04). There were, however, no significant differences both in event-free survival (38.2 +/- 11.2 per cent versus 71.3 +/- 9.3 per cent, P = 0.12) and overall survival (70.0 +/- 10.2 per cent versus 79.6 +/- 8.3 per cent, P = 0.41) between the two groups at 3 years by long-rank test. With the use of risk-directed therapy and improved supportive care, two-thirds of our patients are able to enjoy long-term event-free survival.