Identification of seven novel HLA class I alleles in New Zealand.

Seven new HLA class I alleles have been identified in the New Zealand population in the process of routine HLA typing and they are described here. Unusual bead positivity in Luminex typing identified potential new alleles in a bone marrow registry donor (B*40:285) and two HIV patients prior to abacavir prescription (B*14:02:09, B*41:29). In addition, four new class I alleles were identified through class I sequencing-based typing (SBT) outside of exons 2 and 3. One mutation was identified in exon 4 (new allele C*12:125) and three have been found in exon 5, an exon rarely sequenced. Two stem cell transplant recipients (B*07:02:45, C*03:279) had novel mutations in exon 5 and one was found in exon 5 of a potentially matched unrelated donor from DKMS, previously thought to be B*40:02:01 (B*40:303).

Prevalence and significance of white-coat hypertension and masked hypertension in type 2 diabetics.

OBJECTIVES: To explore the prevalence of various categories of hypertension in diabetic patients, and assess any corresponding associations with end-organ complications. DESIGN: Cross-sectional study. SETTING: Tertiary centre of a regional hospital in Hong Kong. PATIENTS: All ambulatory type 2 diabetic patients attending our clinics from January 2002 to November 2004 were invited to participate in the protocol. RESULTS: A total of 133 diabetic patients were included; 82 had normal clinic blood pressures, 15 (18%) of whom had masked hypertension, the remaining 67 (82%) had 'normotension'. The remaining 51 patients had high clinic blood pressures, of whom 28 (55%) had white-coat hypertension and 23 (45%) had sustained hypertension. Urinary albumin excretion rate was higher in patients with masked hypertension (10 mg/day; range, 7-580 mg/day) and sustained hypertension (7 mg/day; 7-3360 mg/day) in comparison to those with white-coat hypertension (7 mg/day; 7-109 mg/day) or 'normotension' (7 mg/day; 7-181 mg/day) [P<0.01]. Likewise, the prevalence of albuminuria was significantly higher in patients with masked hypertension (40%) and sustained hypertension (26%) than in those with 'normotension' (6%) and white-coat hypertension (11%) [P<0.01]. The prevalence of left ventricular hypertrophy was significantly higher in subjects with masked hypertension (38%) and sustained hypertension (26%) compared to patients with 'normotension' (8%) or white-coat hypertension (11%) [P<0.01]. Left ventricular diastolic dysfunction was more prevalent in patients with masked hypertension (46%), sustained hypertension (48%), and white-coat hypertension (43%) in comparison to subjects with 'normotension' (18%) [P=0.01]. CONCLUSION: Masked hypertension is associated with a higher prevalence of albuminuria, left ventricular diastolic dysfunction, and hypertrophy. White-coat hypertension carries a more benign prognosis than sustained hypertension and masked hypertension. Our cross-sectional study supports the recommendation to performing ambulatory blood pressure measurements in type 2 diabetic patients.

Use of lithium in the treatment of thyrotoxicosis.

OBJECTIVES: To evaluate the efficacy and safety of lithium in the treatment of thyrotoxicosis, and to study the dose and serum levels at which therapeutic response occurs. DESIGN: Retrospective study. SETTING: Thyroid clinic of a regional hospital in Hong Kong. PATIENTS: Thirteen patients with thyrotoxicosis pending therapy with radioiodine or surgery, in whom thionamides were contra-indicated due to adverse reactions or failure of treatment. MAIN OUTCOME MEASURES: Free thyroxine levels, time to euthyroidism, and side-effects of lithium. RESULTS: A satisfactory response, defined as a fall by 40% or more in free thyroxine levels and clinical improvement, was achieved in eight patients within 1 to 2 weeks of lithium therapy. In four others, response occurred in 3 to 5 weeks. Response was slow and inadequate in one patient due to 'escape'. The median dosage of lithium was 750 mg daily, with a range of 500 to 1500 mg daily. The median serum lithium level was 0.63 mmol/L. Lithium toxicity was observed in one patient. CONCLUSIONS: A relatively low dose of lithium offers a safe and effective alternative means of controlling thyrotoxicosis in patients who cannot tolerate or do not respond to thionamides.

Combined orbital irradiation and systemic steroids compared with systemic steroids alone in the management of moderate-to-severe Graves' ophthalmopathy: a preliminary study.

OBJECTIVE: To assess the efficacy and safety of combined orbital irradiation and systemic steroids in the management of moderate-to-severe Graves' ophthalmopathy. DESIGN: Single-blind randomised prospective study. SETTING: Regional hospital, Hong Kong. PATIENTS: Sixteen patients with active moderate-to-severe Graves' ophthalmopathy who were randomly assigned to steroid therapy (ST group) or combination therapy of orbital irradiation and systemic steroids (SRT group) between June 2000 and June 2003. MAIN OUTCOME MEASURES: NOSPECS scoring system, total eye score, subjective eye score, and extra-ocular muscle thickness as determined by either computed tomographic or magnetic resonance imaging scans. RESULTS: The study was completed by 15 of 16 patients. Both groups experienced improvement in total eye score, soft tissue swelling, ocular motility, visual acuity, and subjective eye score at 52-week follow-up. Total eye score improved earlier in the SRT group, achieving statistical significance (P<0.05) at as early as 4 weeks of follow-up. Improvement in ocular parameters was greater and led to a significantly greater reduction in total eye score than in the ST group at weeks 16, 24, and 52. Maximum extra-ocular muscle thickness was significantly reduced in the SRT group only. No change was observed in proptosis in either group. No serious adverse effect was observed with the addition of orbital irradiation to steroid therapy. CONCLUSION: A combination of orbital irradiation and systemic steroids is well tolerated and more effective than steroids alone in the treatment of active moderate-to-severe Graves' ophthalmopathy. It achieves greater and more rapid improvement in soft tissue swelling, ocular motility, and visual acuity.

Medullary thyroid carcinoma in Hong Kong Chinese patients.

OBJECTIVE: To study the clinical parameters and treatment outcome of medullary thyroid carcinoma in Hong Kong Chinese patients. DESIGN: Retrospective study. SETTING: Regional oncology unit, Hong Kong. PATIENTS: Patients with medullary thyroid carcinoma who were identified among 1656 patients with thyroid malignancies seen in a single institute in Hong Kong from January 1960 to June 2003. MAIN OUTCOME MEASURES: Ten-year cause-specific survival, locoregional failure-free survival, and distant metastasis failure-free survival. RESULTS: Twenty-two (1.3%) patients with medullary thyroid carcinoma were identified. The mean age at diagnosis was 43.7 (standard deviation, 16.5) years. The sex ratio was 1:1. The 10-year cause-specific survival, locoregional failure-free survival, and distant metastasis failure-free survival were 75.4%, 82.0%, and 62.4%, respectively. Lymph node metastasis was present in seven (31.8%) patients at diagnosis. Distant metastasis developed in nine (40.9%) patients: lung, 3 (13.6%); bone, 5 (22.7%); liver, 2 (9.1%); mediastinum, 4 (18.2%). Seven (31.8%) patients died of distant metastasis. Mediastinal (n=3) and bone metastases (n=3) were important causes of death. Genetic study confirmed multiple endocrine neoplasia type 2A in 3 (25.0%) of 12 patients who all had bilateral and multifocal diseases. Younger age (<45 years) was associated with better survival, better locoregional control, and less distant metastasis. Patients with pT1N0 disease (n=3) had an excellent prognosis: all were disease-free following total thyroidectomy. Among eight patients who received external radiation therapy, seven achieved good locoregional control. In seven patients with lymph node metastasis, external radiation therapy gave 100% (4/4) locoregional control compared with 33.3% (1/3) in those without external radiation therapy. Chemotherapy using dacarbazine and 5-fluorouracil was tried in three patients with poor response. CONCLUSIONS: Early stage (T1N0) medullary thyroid carcinoma is associated with a very good prognosis. Postoperative external radiation therapy can achieve good locoregional control in patients with lymph node metastasis or locally advanced disease.

A novel B(var) allele (547 G>A) demonstrates differential expression depending on the co-inherited ABO allele.

BACKGROUND AND OBJECTIVES: Genetic analysis of group B donors in Korea was performed. MATERIALS AND METHODS: Exons 6 and 7 were sequenced in 12 phenotypically B3 donors 6 B3, 6 A1B3. RESULTS: Consensus sequences all B3 and 2/6 A1B3 donors were present. Four A1B3 donors demonstrated a novel B allele, B(var), in the context of A101/ or A102/B(var) genotypes. Family studies based on an A1B3 donor with the B(var) allele and on another unrelated subject with identical genotype and phenotype revealed B(var)/O01 genotypes with full B-antigen expression. CONCLUSIONS: B(var) allele is subject to differential expression, depending on the co-inherited ABO allele.

A patient with an increased troponin level without evidence of ischaemic cardiac injury.

A 74-year-old man was admitted for chest infection with acute exacerbation of chronic obstructive pulmonary disease. He was incidentally found to have an increased serum level of cardiac troponin I, despite the absence of symptoms and electrocardiographic evidence of ischaemic heart disease. Troponin I became undetectable after the serum was treated with polyethylene glycol, which removed any interfering antibodies. Serum cardiac troponin T was also undetectable after this treatment. Interference of the cardiac troponin I assay by heterophilic antibodies was thus confirmed. Because of the possibility of false-positive results due to immunoassay interference, clinicians should be alerted whenever laboratory findings are incompatible with the clinical picture, and should be ready to perform additional laboratory tests.

The serological and genetic basis of the cis-AB blood group in Korea.

BACKGROUND AND OBJECTIVES: The cis-AB blood group is rare, although relatively common amongst Koreans. The serological characteristics and genetic basis of Korean cis-AB blood donors were investigated. MATERIALS AND METHODS: Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP), designed to detect the cis-AB01 allele, was performed on 194 AB samples which demonstrated weak or unusual expression of either or both of the A or B antigens. RESULTS AND CONCLUSIONS: Sixty cis-AB01 donors were identified. cis-AB01/O01 or O02 were the most common genotypes (36/60) detected only in A(2)B(3) donors, and cis-AB01/B101 (nine of 60) was the least common genotype identified only in A(2)B donors. Surprisingly cis-AB01/A102 (15/60) was identified in a variety of phenotypes (A(1)B(3), A(1)B(x) or el, A(int)B(3)).

Consensus statement on iodine deficiency disorders in Hong Kong.

This article reviews the available data on the study of iodine deficiency disorders in Hong Kong and to discuss the approach towards preventing such disorders in Hong Kong. The importance of iodine and iodine deficiency disorders is described, and the available data on the dietary iodine intake and urinary iodine concentration in different populations of Hong Kong are summarised and discussed. Dietary iodine insufficiency among pregnant women in Hong Kong is associated with maternal goitrogenesis and hypothyroxinaemia as well as neonatal hypothyroidism. Borderline iodine deficiency exists in the expectant mothers in Hong Kong. Women of reproductive age, and pregnant and lactating women should be made aware and educated to have an adequate iodine intake, such as iodised salt, as an interim measure. A steering group involving all stakeholders should be formed to advise on the strategy of ensuring adequate iodine intake, including universal iodisation of salt in Hong Kong. Continuous surveillance of iodine status in the Hong Kong population is necessary.

A Chinese family with familial dysalbuminaemic hyperthyroxinaemia.

We report the results of biochemical and genetic studies in a Chinese family with familial dysalbuminaemic hyperthyroxinaemia. Total thyroxine levels were 1.2 to 1.7 times the upper limit of the reference range and free thyroxine levels were 1.2 to 1.6 times the upper reference limit. Concentrations of thyroid-stimulating hormone (thyrotropin) and free tri-iodothyronine were normal in all family members tested. Overall, thyroid function tests showed high total thyroxine levels in five males and two females over two generations in the family. The diagnosis of familial dysalbuminaemic hyperthyroxinaemia was confirmed by the detection of a guanine to adenine missense mutation in the second nucleotide of codon 218 of the gene encoding human serum albumin, showing that the mutation in this family is the same as that previously found in Caucasian populations.

Use of the low-dose corticotropin stimulation test for the diagnosis of secondary adrenocortical insufficiency.

OBJECTIVE: To assess the clinical utility and safety of the low-dose corticotropin stimulation test in the diagnosis of secondary adrenocortical insufficiency. DESIGN: Prospective study. SETTING: Regional hospital, Hong Kong. PARTICIPANTS: Seventy-two Chinese patients with suspected secondary adrenocortical insufficiency. MAIN OUTCOME MEASURE: Serum cortisol response during the low-dose corticotropin stimulation test, using the insulin tolerance test as the gold standard. RESULTS: The 30-minute cortisol level during the low-dose corticotropin stimulation test was most closely correlated (r=0.79) with the peak cortisol level achieved during the insulin tolerance test. The optimum sensitivity and specificity of the low-dose corticotropin stimulation test were obtained at a cut-off value of 550 nmol/L or more for the 30-minute cortisol level. Using the insulin tolerance test as the gold standard for comparison, the low-dose corticotropin stimulation test had a sensitivity of 97%, a specificity of 78%, a positive predictive value of 81%, and a negative predictive value of 97% at this cut-off value. The positive likelihood ratio was 4.4 and the negative likelihood ratio 0.04. CONCLUSION: The low-dose corticotropin stimulation test, using the cortisol response at 30 minutes after synacthen 1 microg is a safe, convenient, and sensitive method for screening abnormalities of the hypothalamic-pituitary-adrenocortical axis in Chinese patients suspected of having secondary adrenocortical insufficiency.

Quantitative comparison of expression with adeno-associated virus (AAV-2) brain-specific gene cassettes.

This study compared a range of mammalian CNS expression cassettes in recombinant adeno-associated virus (AAV-2) vectors using strong endogenous promoter sequences, with or without a strong post-regulatory element and polyadenylation signal. Changes in these elements led to transgene expression varying by over three orders of magnitude. In experiments conducted in primary cell culture and in >100 stereotactically injected rats, we observed highly efficient and stable (>15 months) gene expression in neurons and limited expression in glia; the highest expression occurred with endogenous, nonviral promoters such as neuron-specific enolase and beta-actin. The packaging size of AAV-2 was maximized at 5.7 kb without impairing gene expression, as judged by direct comparison with a number of smaller AAV-2 constructs. The genomic insert size and titer were confirmed by Southern blot and quantitative PCR, and infectivity was tested by particle titer using ELISA with a conformation-dependent epitope that requires the full intact capsid. A packaging and purification protocol we describe allows for high-titer, high-capacity AAV-2 vectors that can transduce over 2 x 10(5) neurons in vivo per microliter of vector, using the strongest expression cassette.

A case of giant malignant phaeochromocytoma.

Malignant phaeochromocytoma is defined as the presence of tumour deposits at sites that are normally devoid of chromaffin cells. We report on a 63-year-old man who had a giant malignant phaeochromocytoma of the right adrenal gland that encased the inferior vena cava. The urinary excretion rates of catecholamines and their metabolites were normal, except for normetanephrine, which was excreted at a higher rate than normal. The tumour was surgically unresectable by laparotomy. Postoperatively, the patient was given a 4-month trial of subcutaneous octreotide and intravenous meta-iodobenzylguanidine I 131. Occult lung secondary tumours were first detected by meta-iodobenzylguanidine scintigraphy after 2 years, and the patient died of bone and lung metastases 1 year later. Because phaeochromocytoma is rare, local experience in managing this disease is limited. This report alerts physicians of the methods of diagnosing and managing surgically unresectable malignant phaeochromocytoma.

Physical and biological properties of cationic triesters of phosphatidylcholine.

The properties of a new class of phospholipids, alkyl phosphocholine triesters, are described. These compounds were prepared from phosphatidylcholines through substitution of the phosphate oxygen by reaction with alkyl trifluoromethylsulfonates. Their unusual behavior is ascribed to their net positive charge and absence of intermolecular hydrogen bonding. The O-ethyl, unsaturated derivatives hydrated to generate large, unilamellar liposomes. The phase transition temperature of the saturated derivatives is very similar to that of the precursor phosphatidylcholine and quite insensitive to ionic strength. The dissociation of single molecules from bilayers is unusually facile, as revealed by the surface activity of aqueous liposome dispersions. Vesicles of cationic phospholipids fused with vesicles of anionic lipids. Liquid crystalline cationic phospholipids such as 1, 2-dioleoyl-sn-glycero-3-ethylphosphocholine triflate formed normal lipid bilayers in aqueous phases that interacted with short, linear DNA and supercoiled plasmid DNA to form a sandwich-structured complex in which bilayers were separated by strands of DNA. DNA in a 1:1 (mol) complex with cationic lipid was shielded from the aqueous phase, but was released by neutralizing the cationic charge with anionic lipid. DNA-lipid complexes transfected DNA into cells very effectively. Transfection efficiency depended upon the form of the lipid dispersion used to generate DNA-lipid complexes; in the case of the O-ethyl derivative described here, large vesicle preparations in the liquid crystalline phase were most effective.

O-ethylphosphatidylcholine: A metabolizable cationic phospholipid which is a serum-compatible DNA transfection agent.

1,2-dioleoyl-sn-glycero-3-ethylphosphocholine was prepared in a one-step reaction from phosphatidylcholine by reaction with ethyl trifluoromethanesulfonate. This and related O-alkyl phosphatidylcholines constitute the first chemically stable triesters of biological lipid structures and the first cationic derivatives of phospholipids consisting entirely of biological metabolites linked with ester bonds. The complex of cationic phospholipid and plasmid DNA transfected cells with high efficiency. Maximum efficiency of transfection was obtained with complexes in which the positive charge was a few percent in excess over the negative charge. Modest stimulation of transfection of common cell lines was obtained by continuous culture in the presence of 10% serum. Incubation of the phospholipid complex for at least 2 h at 37 degrees C in nearly pure serum had no deleterious effects on transfection efficiency. The lipid has low toxicity; BHK cells tolerated amounts of 2 mg/2 x 10(6) cells at concentrations of 1 mg/mL. The lipid is biodegradable; it was hydrolyzed by phospholipase A(2) in vitro and was metabolized with a half-life of a few days in cells in culture. The synthetic route to cationic phospholipids is well suited to the preparation of derivatives that are tailor-made to have a wide variety of different properties.

Absence of PAX2 gene mutations in patients with primary familial vesicoureteric reflux.

Vesicoureteric reflux (VUR) is a common childhood condition characterised by regurgitation of urine from the bladder to the kidney. It is the commonest cause of end stage renal failure in children and an important cause in adults. Primary VUR is often familial, suggesting that genetic factors play an important role in its aetiology. Recently, VUR was observed as part of a syndrome, involving optic nerve colobomas and renal anomalies, caused by mutations of the PAX2 gene. PAX2 is a member of the paired box family of genes and is expressed in the ureteric bud and differentiating nephrogenic mesenchyme of the developing kidney. PAX2 has been shown to play a critical role in the development of both the kidney and the ureter. The occurrence of VUR in one family with the PAX2 mutation, and the expression pattern of PAX2 in developing ureteric bud, strongly suggested that PAX2 could be the cause of primary familial VUR. Single strand conformational polymorphism (SSCP) analysis of 23 affected subjects in eight families with primary familial VUR showed no alterations in exons 2-5 of the PAX2 gene. In addition, a polymorphic dinucleotide repeat marker located within the PAX2 gene segregated independently of the disease trait in one large family who primarily had VUR or reflux nephropathy. These results suggest that PAX2 is not a major cause of primary familial reflux.

Primary hyperparathyroidism in Hong Kong: an analysis of 44 cases.

Primary hyperparathyroidism is increasingly being diagnosed subsequent to the detection of hypercalcaemia using multichannel auto-analyser screening. This paper provides a local picture of the clinical presentation and management of primary hyperparathyroidism. A retrospective review was conducted of 44 patients with primary hyperparathyroidism who were treated at the Queen Elizabeth Hospital between January 1987 and July 1996. Twenty-five (56.8%) of the patients were asymptomatic. Only three (6.8%) patients gave radiograms that had features indicating primary hyperparathyroidism; seven (15.9%) had renal stones. The patients underwent one or more of the following localisation procedures: computerised tomography, ultrasonography, thallium-technetium subtraction scanning, and technetium Tc 99m sestamibi scanning. The latter method was the most sensitive (64.3%). Ten adenomas that could not be localised by any of these procedures were successfully removed during surgery. Surgery was successful in 94.4% of cases and surgical outcome was comparable to that reported in the literature.

Pharmacokinetics, pharmacodynamics, long-term efficacy and safety of oral 1-deamino-8-D-arginine vasopressin in adult patients with central diabetes insipidus.

1. The pharmacokinetics and pharmacodynamics of intranasal (IN) and oral 1-deamino-8-D-arginine vasopressin (DDAVP) were compared in 10 Chinese adults with central diabetes insipidus previously controlled on IN DDAVP. This was followed by comparison of the acute pharmacodynamics of commonly used oral preparations (containing 100, 200 and 400 micrograms per tablet) and a 1 year prospective evaluation of the long-term safety and efficacy of oral DDAVP. 2. Following 20 micrograms IN and 200 micrograms orally, respective plasma DDAVP concentrations peaked after 45.6 +/- 7.3 and 93.3 +/- 3.3 (mean +/- s.e.mean) min, reaching 24.1 +/- 4.7 and 15.1 +/- 3.2 pmol 1(-1) and respective terminal half-lives were 2.2 +/- 0.1 and 2.0 +/- 0.1 h. Based on the area under the concentration-time-curve, the bioequivalent IN/oral ratio was 1:16. 3. As judged by changes in urine flow rate and osmolality after IN or oral (100, 200 or 400 micrograms) DDAVP, antidiuretic activity increased rapidly during the second hour and peaked at 4 h. The antidiuresis duration and magnitude correlated with the oral dose (P < 0.001 and < 0.05 respectively), and was least following 100 micrograms (P < 0.01 vs 200 or 400 micrograms). Increasing the dose from 200 to 400 micrograms did not increase maximal antidiuretic activity significantly, but there was a trend towards a longer duration of action (P = 0.076). 4. During the 1-year prospective study with oral DDAVP 300-600 micrograms per day in two to three doses, stable and satisfactory antidiuresis (comparable with that on previous IN therapy) was maintained; tablets were well-tolerated and no side-effect warranted drug withdrawal. 5. These findings suggest that the 100 and 200 micrograms preparations of oral DDAVP are adequate for the long-term control of central diabetes insipidus in our population, and that the 400 micrograms preparation may have a role if the frequency of administration is to be reduced.