A novel mutation in pseudohypoparathyroidism type 1a in a Chinese woman and her son with hypocalcaemia.

Pseudohypoparathyroidism is a rare genetic disorder characterised by end-organ resistance to parathyroid hormone due to a defect of the guanine nucleotide-binding protein alpha that simulates activity of the polypeptide 1 (GNAS) gene. Patients with type 1a pseudohypoparathyroidism display different features of Albright's hereditary osteodystrophy as well as multi-hormone resistance. We describe a Chinese woman and her son, who presented with different symptoms of pseudohypoparathyroidism and clinically manifested different degree of Albright's hereditary osteodystrophy. Genetic study detected a mutation [NM_000516.4(GNAS):c682C>T (p.Arg228Cys)] in the GNAS gene.

Primary hyperaldosteronism among Chinese hypertensive patients: how are we doing in a local district in Hong Kong.

OBJECTIVES: To estimate the point prevalence of primary hyperaldosteronism in a government out-patient setting and to compare associated patient characteristics with those having essential hypertension. DESIGN: Case series with external comparison. SETTING: A single public hospital (Caritas Medical Centre) and all five associated general out-patient clinics in Sham Shui Po district in Hong Kong. PATIENTS: All patients with confirmed primary hyperaldosteronism and randomly selected patients with essential hypertension from a medical specialist clinic and general out-patient clinics, retrieved from a computer database for the period January 2007 to December 2008. MAIN OUTCOME MEASURES: Estimated point prevalence of primary hyperaldosteronism among hypertensive patients treated in the public sector of Sham Shui Po district. Patient age when hypertension was diagnosed, number of antihypertensive drugs used for treatment, and the presence of target organ damage in the patients with primary hyperaldosteronism and those with essential hypertension were compared. RESULTS: Among the 46 012 patients receiving antihypertensive treatment, 49 were confirmed to have primary hyperaldosteronism. The estimated point prevalence of primary hyperaldosteronism among these hypertensive patients was 0.106% only, which was far smaller than figures from other countries. When compared with the 147 patients with essential hypertension by multivariate analysis, those with primary hyperaldosteronism were: (1) associated with longer durations of hypertension (odds ratio=1.14; 95% confidence interval, 1.06-1.24) despite being younger at the time of study, (2) likely to be taking three or more antihypertensive drugs (odds ratio=2.51; 95% confidence interval, 1.59-3.95), and (3) more likely to have left ventricular hypertrophy (odds ratio=5.01; 95% confidence interval, 1.83-13.69). All primary hyperaldosteronism patients studied presented with hypokalaemia. The need for antihypertensive drugs was markedly reduced after adrenalectomy for adrenal adenoma. CONCLUSIONS: Primary hyperaldosteronism, which is potentially a surgically curable cause of hypertension, appeared to be underdiagnosed in our locality. Screening by aldosterone-renin ratio of high-risk individuals may help improve patient outcomes.

Phaeochromocytoma in the Hong Kong Chinese population.

OBJECTIVE: To review the clinical manifestations of phaeochromocytoma in a Hong Kong Chinese population. DESIGN: Retrospective review. SETTING. Five public hospitals in Hong Kong. PATIENTS: Seventeen patients with operated phaeochromocytoma between 1994 and 2003 were reviewed retrospectively. RESULTS: Six patients (35%) were men, 11 (65%) were women. The mean age at presentation was 47 (range, 17-72) years. The diagnosis post-presentation was delayed by 1 to 132 months. Over 70% of the patients had hypertension. The most frequent symptoms were headache (53%), palpitations (53%), and sweating (41%); all these symptoms were present in 24% of the patients. Four (24%) had hereditary phaeochromocytoma/paraganglioma syndrome. The sensitivity of 24-hour urinary catecholamine measurements was 82%. Mean urinary adrenaline and noradrenaline concentrations were respectively 7- and 8-fold greater than the upper reference limits. Computed tomography and metaiodobenzylguanidine scintigraphy were the most widely used means for tumour localisation (sensitivity, 100% and 87% respectively). Approximately 65% of the patients had intra-adrenal tumours; 53% were on right side, 18% were bilateral. All the patients were prescribed phenoxybenzamine (dosage range, 20-120 mg/day) preoperatively. Two thirds of the patients had improved blood pressure 1 year after the operation. No malignancy was reported after a mean follow-up period of 7 years. CONCLUSION: Our series of patients with phaeochromocytomas commonly had a high frequency of normotension and extra-adrenal tumours. A high index of clinical suspicion and appropriate biochemical investigations are necessary to make the diagnosis, especially for patients manifesting adrenal incidentaloma and extra-adrenal lesion.

Severe right heart failure in two patients with thyrotoxicosis.

Congestive heart failure is a recognised complication of uncontrolled thyrotoxicosis but isolated right heart failure is rarely seen in association with thyrotoxicosis. Two cases of right heart failure associated with thyrotoxicosis are presented. In a 45-year-old man with right heart failure, investigations for all common secondary causes of right heart failure were negative. The only concurrent disease identified was thyrotoxicosis. The right heart failure subsided after treatment of the thyrotoxicosis. In a 36-year-old woman, the right heart failure had two underlying causes, thyrotoxicosis and an atrial septal defect. Treatment of thyrotoxicosis alone resulted in improvement of pulmonary hypertension and right heart failure. Thyrotoxicosis should be considered as a possible cause of pulmonary hypertension or isolated right heart failure.

Selective alterations in biosynthetic and endocytic protein traffic in Madin-Darby canine kidney epithelial cells expressing mutants of the small GTPase Rac1.

Madin-Darby canine kidney (MDCK) cells expressing constitutively active Rac1 (Rac1V12) accumulate a large central aggregate of membranes beneath the apical membrane that contains filamentous actin, Rac1V12, rab11, and the resident apical membrane protein GP-135. To examine the roles of Rac1 in membrane traffic and the formation of this aggregate, we analyzed endocytic and biosynthetic trafficking pathways in MDCK cells expressing Rac1V12 and dominant inactive Rac1 (Rac1N17). Rac1V12 expression decreased the rates of apical and basolateral endocytosis, whereas Rac1N17 expression increased those rates from both membrane domains. Basolateral-to-apical transcytosis of immunoglobulin A (IgA) (a ligand for the polymeric immunoglobulin receptor [pIgR]), apical recycling of pIgR-IgA, and accumulation of newly synthesized GP-135 at the apical plasma membrane were all decreased in cells expressing Rac1V12. These effects of Rac1V12 on trafficking pathways to the apical membrane were the result of the delivery and trapping of these proteins in the central aggregate. In contrast to abnormalities in apical trafficking events, basolateral recycling of transferrin, degradation of EGF internalized from the basolateral membrane, and delivery of newly synthesized pIgR from the Golgi to the basolateral membrane were all relatively unaffected by Rac1V12 expression. Rac1N17 expression had little or no effect on these postendocytic or biosynthetic trafficking pathways. These results show that in polarized MDCK cells activated Rac1 may regulate the rate of endocytosis from both membrane domains and that expression of dominant active Rac1V12 specifically alters postendocytic and biosynthetic membrane traffic directed to the apical, but not the basolateral, membrane.

The importance of the interpretation of urine catecholamines is essential for the diagnosis and management of patient with dopamine-secreting paraganglioma.

Phaeochromocytoma or paraganglioma that exclusively secretes dopamine is very rare. This case illustrates its atypical presentation and the importance of interpretative reporting for urine catecholamines leading to the diagnosis and subsequent management of a patient with this condition. We report a 71-year-old Chinese woman with a large dopamine-secreting paraganglioma. She presented with low back pain for six months. On examination, a right abdominal mass was palpable incidentally. Her blood pressure was normal throughout. Serial 24-h urine collections for catecholamines showed enormous elevation of urine dopamine excretion to 80.7 micromol/day (normotensive:<2.6 m mol/day). However, the daily excretions of urine adrenaline and noradrenaline, as well as their metabolites were within their respective reference intervals. Good communication between chemical pathologists and physicians prompted the arrangement of the whole body 131I-meta-iodobenzylguanidine (MIBG) scintigraphy, which showed a large signal in the right upper quadrant of the abdomen corresponding to a large extra-adrenal tumour detected by both ultrasonography and computerized tomography (CT) of the abdomen. Histological section of the tumour tissue revealed paraganglioma, which stained positive for chromogranin and neuron-specific enolase. After four months, the patient presented with chest symptoms and CT of the thorax revealed multiple nodules. Lung metastases were suspected. However, follow-up urine catechola- mine and dopamine excretions were again within their respective normotensive reference intervals. A second MIBG scintigraphy was performed, but no specific uptake at either the thorax or the abdomen could be demonstrated. Fine-needle aspiration cytology using the thoracoscopic technique was performed and immunochemical staining of the biopsy specimen showed the presence of non- small-cell carcinoma of the lung.

A founder mutation (R254X) of SLC22A5 (OCTN2) in Chinese primary carnitine deficiency patients.

Mutations in the SLC22A5 gene, which encodes for the plasma membrane carnitine transporter OCTN2, cause primary carnitine deficiency (PCD). After our first report of OCTN2 mutations in Chinese, three more Chinese PCD patients were identified. The parents of these families were non-consanguineous and these families were unrelated. Two novel truncating mutations were found: R254X, a single-base mutation at cDNA position 981 (c.981C>T); and Y387X (c.1382T>G). Two probands, one each from Taiwan and Macau, were homozygous for R254X. The other proband from Taiwan carried both R254X and Y387X. Two additional heterozygote carriers of R254X were also identified among 250 control samples, while none was detected for Y387X. The population carrier rate for R254X would be about 1 in 125. Haplotypes of R254X alleles were examined and patients homozygous for R254X were also homozygous for the same haplotype of intragenic and microsatellites markers. Analysis of population frequencies of haplotypes revealed that the chance of 4 chromosomes having arisen as independent events was 0.016. We conclude that R254X is probably a founder mutation in Chinese. Other previously reported mutations found in the Japanese population were also screening in 250 control samples but no carrier was identified, indicating that they were either very rare or not present in Southern Chinese.

Inhibitors of NF-kappaB and AP-1 gene expression: SAR studies on the pyrimidine portion of 2-chloro-4-trifluoromethylpyrimidine-5-[N-(3', 5'-bis(trifluoromethyl)phenyl)carboxamide].

We investigated the structure-activity relationship studies of N-[3, 5-bis(trifluoromethyl)phenyl][2-chloro-4-(trifluoromethyl)pyrimidin-5 -yl]carboxamide (1), an inhibitor of transcription mediated by both NF-kappaB and AP-1 transcription factors, with the goal of improving its potential oral bioavailability. Compounds were examined for cell-based activity, were fit to Lipinski's rule of 5, and were examined for potential gastrointestinal permeability using the intestinal epithelial cell line, Caco-2. Selected groups were substituted at the 2-, 4-, and 5-positions of the pyrimidine ring using solution-phase combinatorial methodology. The introduction of a fluorine in the place of 2-chlorine of 1 resulted in a compound with comparable activity. However, other substitutions at the 2-position resulted in a loss of activity. The trifluoromethyl group at the 4-position could be replaced with a methyl, ethyl, chlorine, or phenyl without a substantial loss of activity. The carboxamide group at the 5-position is critical for activity. If it was moved to the 6-position, the activity was lost. The 2-methyl analogue of 1 (81) showed comparable in vitro activity and improved Caco-2 permeability compared to 1.

Infective thyroiditis in two cases of systemic lupus erythematosus.

We report on two patients with systemic lupus erythematosus, both of whom developed suppurative thyroiditis. One suffered from Staphylococcus aureus-induced thyroiditis and the other had tuberculous thyroiditis. The occurrence of tuberculous thyroiditis in systemic lupus erythematosus has not previously been reported. The diagnoses were made by fine-needle aspiration biopsy and subsequent bacteriological confirmation. Transient alteration of thyroid function was observed in both patients. In patients with systemic lupus erythematosus who present with fever and anterior neck pain, infection of the thyroid gland should be considered, and appropriate investigations undertaken.

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.

Incidence and progression of diabetic retinopathy in Hong Kong Chinese with type 2 diabetes mellitus.

OBJECTIVE: We conducted a cohort study to determine the incidence and progression of diabetic retinopathy (DR) in a Chinese population with type 2 diabetes mellitus in a district hospital in Hong Kong, and to identify the risk factors associated with the development and progression of DR over 4 years. RESEARCH DESIGN AND METHODS: A total of 413 type 2 diabetic patients who followed up in our diabetic clinic and had a diabetic complication screening performed in 2001 were studied. The final analysis included 354 subjects (85.7%) after a mean follow-up period of 4.2 years. The severity of DR was graded according to the modified Early Treatment Diabetic Retinopathy Study (ETDRS). The relationship between clinical variables and DR development and progression was determined. RESULTS: The baseline prevalence of DR was 39.2%. On 4-year follow-up, the incidence of DR was 20.3% (43 of 212). In those with baseline DR, 34.7% (42 of 121) progressed by >or=2 steps in ETDRS. On multivariate analysis, a high baseline glycosylated hemoglobin (HbA(1c)) was the only predictor of DR development, while macroalbuminuria and high mean HbA(1c) predicted progression. Regression of DR, defined by a >or=2-step decrement in ETDRS, occurred in 13.2% (12 of 91) of subjects and was associated with lower baseline HbA(1c) and absence of albuminuria. CONCLUSION: The incidence of DR in our study was similar to--but progression of DR was higher than--those reported in Caucasians. More frequent retinal screening should be offered to those with baseline DR, high HbA(1c), or albuminuria. Good glycemic control is important in order to prevent the development and progression of DR, and can lead to regression of DR.

Cardiac blood flow studies in fetuses with haemoglobin Bart's disease.

Blood flow across the atrioventricular valves and outflow tracts was measured in 55 normal fetuses and 32 fetuses with haemoglobin (Hb) Bart's disease between 18 and 26 weeks of gestation. The mean velocities remained unchanged in both normal and affected fetuses over the gestations studied. The volume flow across both atrioventricular valves and outflow tracts increased as the gestation advanced in both normal and affected fetuses, but was significantly higher in affected than in normal fetuses. The same magnitude of increased flow was found in both hydropic and non-hydropic fetuses with Hb Bart's disease. These findings suggest that fetuses with severe and long-standing anaemia have a remarkable cardiac compensatory mechanism for the maintenance of tissue oxygenation. In response to anaemia and circulatory loading, the cardiac chambers and outflow tracts enlarge proportionately up to twice the normal values. Because of this response and the operation of the Frank-Starling mechanism, the heart is able to maintain a normal mean velocity of propulsion and the net output is increased to two to three times that in normal fetuses. Hydropic changes in these anaemic fetuses appear unrelated to cardiac failure as cardiac failure is not observed at the time that hydropic changes develop.

Fat-free mass estimation by bioelectrical impedance and anthropometric techniques in Chinese children.

There is limited information on the accuracy of bioelectrical impedance analysis (BIA) for estimating body composition in children. The purpose of this study was to evaluate BIA measurements for estimating fat mass and fat-free mass in 94 Chinese boys and girls aged 11-17 years. Percent fat (%fatskf) and fat-free mass (FFMskf) were predicted by regression of skinfolds in an equation which is founded on a multicomponent model of body composition in children. Multiple-regression analyses were applied to the data to determine if height2 divided by resistance (resistance index) (RI) could accurately predict FFMskf and %fat. Correlations (R) and predictive accuracy (standard error of the estimate, S.E.E.) for FFMskf for RI alone were 0.94 and 2.7 kg; for RI and body mass this improved to 0.96 and 2.2 kg, and for estimation of %fatskf from RI and body mass these values were 0.78 and 4.7%, respectively. A previously published prediction equation, developed on Caucasian children and which also used RI and body mass, was also cross-validated with the Chinese sample in this study. There was no difference between the predicted values from this equation and FFM and %fat predicted by the skinfold technique. The correlation coefficient for FFM was 0.96 and the S.E.E. was similar to that originally reported for the Caucasian sample. We conclude that BIA is a reliable and acceptably accurate method of estimating anthropometrically determined body composition in Chinese youth.

Effects of SP500263, a novel selective estrogen receptor modulator, on bone, uterus, and serum cholesterol in the ovariectomized rat.

We describe here the activity of a novel selective estrogen receptor modulator, SP500263. When given to adult ovariectomized (OVX) rats for 28 days at doses of 0.3, 1, or 3 mg/kg/day, we found that SP500263 partially protected against OVX-induced loss of bone mineral content in the distal ends of femurs and in the whole bone. SP500263 also antagonized the OVX-induced increase in body weight. However, unlike 17beta-estradiol, SP500263 at efficacious doses did not prevent the OVX-induced loss in uterine wet weight. A small but significant effect on uterine wet weight was noted with raloxifene dosed at 1 mg/kg. As expected, SP500263 but not raloxifene acted as an estrogen antagonist on the uterus in adult rats when administered for 7 days at 30 mg/kg/day. Finally, SP500263 had no statistically significant effects on total serum cholesterol and serum triglycerides in OVX rats treated for 28 days. Raloxifene had no significant effects on body weight, bone mineral content, and serum cholesterol or triglycerides in the OVX-rat model. In summary, SP500263 is a new orally active SERM that acts in rats as an estrogen agonist on bone without causing uterine stimulatory effects.