Comparison of bone structure and microstructure in the metacarpal heads between patients with psoriatic arthritis and healthy controls: an HR-pQCT study.

Human cadaveric study has indicated that the metacarpal head (MCH) is intracapsular in location. We hypothesized that exposure to the intra-articular inflammatory milieu in psoriatic arthritis (PsA) will lead to bone loss in the MCH. INTRODUCTION: To compare the bone structure and microstructure in the MCH between patients with PsA and healthy controls by high-resolution peripheral quantitative CT (HR-pQCT), and to ascertain factors associated with bone loss in PsA patients. METHODS: Sixty-two PsA patients without joint destruction and 62 age-, gender-, and body mass index-matched healthy subjects underwent HR-pQCT imaging of the second and third MCH (MCH 2&3). The number and volume of bone erosion and enthesiophytes, as well as volumetric bone mineral density (vBMD) and microstructure at the MCH 2&3, were recorded. Correlation analysis and multivariable linear regression models were used to determine the association of demographic and disease-specific variables with compromised bone structure and microstructure in PsA. RESULTS: At the MCH 2&3, bone erosion (p = 0.003) and enthesiophyte (p = 0.000) volumes in PsA patients were significantly larger than healthy controls. In PsA patients, older age was associated with a larger erosion and enthesiophyte volume. Concerning the mean vBMD and microstructure at the MCH 2&3, PsA patients had significantly lower mean vBMD (average vBMD - 6.9%, trabecular vBMD - 8.8%, peri-trabecular vBMD - 7.7%, meta-trabecular vBMD - 9.8%), trabecular bone volume fraction (- 8.8%), and trabecular thickness (- 8.1%) compared with control subjects. Multivariable regression analysis revealed that older age and a higher C-reactive protein level were associated with trabecular bone loss. CONCLUSIONS: PsA patients had a higher burden of bone damages (erosions and enthesiophytes) and trabecular bone loss compared with healthy control at the MCH. Inflammation contributed to the deterioration in trabecular microstructure in these patients.

Tropospheric volatile organic compounds in China.

Photochemical smog, characterized by high concentrations of ozone (O3) and fine particles (PM2.5) in the atmosphere, has become one of the top environmental concerns in China. Volatile organic compounds (VOCs), one of the key precursors of O3 and secondary organic aerosol (SOA) (an important component of PM2.5), have a critical influence on atmospheric chemistry and subsequently affect regional and global climate. Thus, VOCs have been extensively studied in many cities and regions in China, especially in the North China Plain, the Yangtze River Delta and the Pearl River Delta regions where photochemical smog pollution has become increasingly worse over recent decades. This paper reviews the main studies conducted in China on the characteristics and sources of VOCs, their relationship with O3 and SOA, and their removal technology. This paper also provides an integrated literature review on the formulation and implementation of effective control strategies of VOCs and photochemical smog, as well as suggestions for future directions of VOCs study in China.

Evaluation of the effectiveness of air pollution control measures in Hong Kong.

From 2005 to 2013, volatile organic compounds (VOCs) and other trace gases were continuously measured at a suburban site in Hong Kong. The measurement data showed that the concentrations of most air pollutants decreased during these years. However, ozone (O3) and total non-methane hydrocarbon levels increased with the rate of 0.23 ± 0.03 and 0.34 ± 0.02 ppbv/year, respectively, pointing to the increasing severity of photochemical pollution in Hong Kong. The Hong Kong government has ongoing programs to improve air quality in Hong Kong, including a solvent program implemented during 2007-2011, and a diesel commercial vehicle (DCV) program since 2007. From before to after the solvent program, the sum of toluene, ethylbenzene and xylene isomers decreased continuously with an average rate of -99.1 ± 6.9 pptv/year, whereas the sum of ethene and propene increased by 48.2 ± 2.0 pptv/year from before to during the DCV program. Despite this, source apportionment results showed that VOCs emitted from diesel exhaust decreased at a rate of -304.5 ± 17.7 pptv/year, while solvent related VOCs decreased at a rate of -204.7 ± 39.7 pptv/year. The gasoline and liquefied petroleum gas vehicle emissions elevated by 1086 ± 34 pptv/year, and were responsible for the increases of ethene and propene. Overall, the simulated O3 rate of increase was lowered from 0.39 ± 0.03 to 0.16 ± 0.05 ppbv/year by the solvent and DCV programs, because O3 produced by solvent usage and diesel exhaust related VOCs decreased (p < 0.05) by 0.16 ± 0.01 and 0.05 ± 0.01 ppbv/year between 2005 and 2013, respectively. However, enhanced VOC emissions from gasoline and LPG vehicles accounted for most of the O3 increment (0.09 ± 0.01 out of 0.16 ± 0.05 ppbv/year) in these years. To maintain a zero O3 increment in 2020 relative to 2010, the lowest reduction ratio of VOCs/NOx was ∼1.5 under the NOx reduction of 20-30% which was based on the emission reduction plan for Pearl River Delta region in 2020.

Focused parathyroidectomy without intra-operative parathyroid hormone monitoring for primary hyperparathyroidism: results in a low-volume hospital.

BACKGROUND: The role of routine intra-operative parathyroid hormone monitoring for sporadic primary hyperparathyroidism is contentious. Satisfactory results can be achieved in high-volume centres. The results of low-volume hospitals are rarely studied. METHODS: A retrospective, non-comparative study was conducted. From November 2002 to October 2012, 105 patients with clinically sporadic primary hyperparathyroidism underwent focused parathyroidectomy without intra-operative parathyroid hormone monitoring. Single adenoma was localised on pre-operative ultrasonography or sestamibi scan. The cure rate, surgical complication rate and pathology findings were evaluated. RESULTS: Most of the operations (63.8 per cent) were performed under local anaesthesia. All but two patients (98.1 per cent) were cured after surgery. There was only one case of double adenomas. No recurrent hyperparathyroidism was observed after a mean follow up of 56.9 months. Surgical complications comprised two cases (1.9 per cent) of transient vocal fold palsy and one case (1.0 per cent) of permanent vocal fold palsy. Seven patients (6.7 per cent) suffered temporary hypocalcaemia. CONCLUSION: Satisfactory results of focused parathyroidectomy without routine intra-operative parathyroid hormone monitoring for appropriately selected primary hyperparathyroidism cases can be attained in a low-volume hospital.

Right-sided pyriform sinus fistula in an adult.

Pyriform sinus fistula is important despite its rarity, as it can induce a recurrent neck abscess. Most of the reported cases occur in children and the majority affect only the left side. We report a patient with a pyriform sinus fistula of the right neck in an adult, which was successfully treated by surgery. The aetiology of this entity is also discussed herein.

Disease control of differentiated thyroid carcinomas by hemithyroidectomy.

INTRODUCTION: Most differentiated thyroid carcinomas (DTC) are treated by total thyroidectomy in Hong Kong. This study investigates the outcome of tumour control in selected patients treated by hemithyroidectomy, which is beneficial in terms of having a lower operative morbidity. METHODS: This is a retrospective study of prospectively collected data from our cancer registry. Patients with pathologically proven differentiated thyroid carcinoma were stratified into risk groups according to the patients' age, tumour size, extrathyroid spread and distant metastasis. Low-risk patients were managed with hemithyroidectomy without postoperative radioactive iodine. Central compartment lymph node dissection was also carried out if the diagnosis was confirmed preoperatively. The oncological outcome and surgical morbidity were evaluated. RESULTS: A total of 236 patients with the diagnosis of DTC underwent a thyroidectomy at our institution during a 24-year period. 93 patients were initially treated by hemithyroidectomy. Subsequent evaluation was focused on this subgroup. The mean follow-up period was 63.3 +/- 55.1 months. The mean tumour diameter was 22.1 +/- 20.8 mm. The histopathologic diagnoses were papillary carcinoma (69 cases; 74.2 percent), follicular carcinoma (20 cases; 21.5 percent) and Hurthle cell carcinoma (four cases; 4.3 percent). 23 (24.7 percent) patients underwent hemithyroidectomy coupled with central compartment dissection. Pathologically proven lymph node metastasis was diagnosed in 12 (12.9 percent) patients. Transient vocal cord palsy occurred in six (6.5 percent) patients, while permanent vocal cord palsy occurred in two (2.2 percent). Local tumour recurrence arose in only one (1.1 percent) patient. No patient succumbed to the thyroid cancer. CONCLUSION: Hemithyroidectomy coupled with central compartment dissection in selected cases of DTC can achieve excellent tumour control with minimal surgical morbidity.

Mammographic determination of breast volume by elliptical cone estimation.

BACKGROUND: We propose a new breast volume calculation method, treating the breast as an elliptical cone on craniocaudal and medial-lateral-oblique mammograms. This study aims to compare the accuracy and reproducibility of this proposed calculation method to the old Katariya method, which calculates breast volume as a circular cone on the craniocaudal mammogram only. MATERIALS AND METHODS: From January 2005 to December 2006, 83 mastectomy patients with recorded breast weight and available preoperative mammographic films were included in the present study. Two surgeons independently measured breast height and width on the preoperative craniocaudal and medial-lateral-oblique mammograms. Breast volume was calculated as a circular cone in the craniocaudal view, and as an elliptical cone in both the craniocaudal and the medial-lateral-oblique mammograms. The accuracy of each method was determined and compared by linear regression analyses. Interobserver variability was assessed by bivariate correlation. RESULTS: The most accurate formula for calculating breast volume was the one that assumed the elliptical cone projection. The mean error of estimated breast volume using the elliptical cone (EC) formula is 3.8 cm(3) (standard deviation [SD] = 133 cm(3)). The mean error of traditional circular cone (CC) formula is -51.3 cm(3) (SD = 182 cm(3)). From a linear regression model, the correlation coefficient of estimated breast volume using EC formula measured 0.977, whereas that using the CC formula measured 0.952 (Fig. 1). Measurements were reproducible between the two independent observers; the Pearson correlation for the EC formula is 0.93 (p < 0.001), and that for the CC formula is 0.95 (p < 0.001). CONCLUSIONS: Breast volume can be accurately determined from measurements made on mammograms. The proposed EC formula calculating breast volume on both the craniocaudal and the medial-lateral-oblique mammograms may be more accurate, as the horizontal and vertical dimensions of the breast are not always the same. In addition, height measurement on the medial-lateral-oblique film can eliminate the compression error as the craniocaudal film may miss the base of the breast and underestimate the breast volume. Taking both mammogram views for measurement is comparably reproducible to the traditional method. Reproducibility of measurement can be further enhanced by better defining the point of measurements.

Cosmetic outcome and percentage of breast volume excision in oncoplastic breast conserving surgery.

BACKGROUND: Since breast-conserving surgery demonstrated identical long term survival on seven randomized trials, it has become the preferred treatment option over mastectomy. Oncoplastic surgery applying simple reshaping and displacement techniques allows inclusion of patients with large tumors in the group selected for breast-conserving surgery. However, the cosmetic outcome and the degree of patient satisfaction, especially in relation to the original breast volume and the percentage of breast tissue excised is not well documented. OBJECTIVE: The present study was designed to assess patient satisfaction with cosmetic outcome after oncoplastic breast-conserving surgery, and to establish the correlation between patient satisfaction and percentage of breast volume excision (PBVE). MATERIALS AND METHODS: A total of 169 Asian patients underwent breast-conserving surgery for primary breast cancer at either United Christian Hospital (UCH) or Hong Kong Sanatorium and Hospital (HKSH) from Nov 2007 to Jan 2008 by two breast surgeons. Among this group, 162 patients with breast-conserving surgery incorporating oncoplastic techniques were prospectively recruited for study. Tumor characteristics, patient satisfaction, cosmetic outcome and surgeons' score were prospectively documented. Breast volume (BV) calculation was based on preoperative mammography (BV = 1/3pir(1)r(2)h), which was validated by our previous study to correlate strongly with actual BV (r = 0.98). PBVE was calculated by dividing the fresh specimen weight by the calculated BV. A standardized questionnaire was used to assess patient satisfaction and surgeons' score on cosmetic outcome during the first 1-3 postoperative months. The correlation between PBVE and patient satisfaction was studied. RESULTS: The median age of the group of patients studied was 52 years (range: 20-96 years). The median tumor size was 2.5 cm (range: 0.6-5 cm). The median breast volume was 493 cm(3) (range: 210-1,588 cm(3)). The median PBVE was 7.4% (range: 1-42%), and 94% of patients were very satisfied or satisfied with the cosmetic outcome. In addition, 85% of patients felt that the treated breast was nearly identical with or only slightly different from the untreated breast. In scoring breast shape, surgeons indicated that 89% of the treated breasts were identical to or only minimally different from the untreated breast. Patient satisfaction decreased significantly when the PBVE exceeded 20%. Neither tumor location nor distance of the tumor from the nipple had any effect on patient satisfaction. CONCLUSIONS: This study showed high patient satisfaction and good cosmetic outcome after oncoplastic breast-conserving surgery, even in small breast sized Asian women. The application of oncoplastic technique allows large volume excision, and satisfaction remains high with breast volume excision less than 20% regardless of tumor location or distance of the tumor from the nipple. More complicated oncoplastic techniques, e.g., breast replacement, might be required if breast volume excision exceeds 20%.

On the relationship between ozone and its precursors in the Pearl River Delta: application of an observation-based model (OBM).

BACKGROUND, AIM, AND SCOPE: Photochemical smog, characterized by high concentrations of O(3) and fine particles, is of great concern in the urban areas, in particular megacities and city clusters like the Pearl River Delta. MATERIALS, METHODS, AND RESULTS: Ambient ozone (O(3)) and its precursors were simultaneously measured at two sites in the Pearl River Delta, namely, Wan Qing Sha (WQS) in Guangzhou and Tung Chung (TC) in Hong Kong, from 23 October to 01 December 2007 in order to explore their potential relationship. Eight high O(3) episode days were identified at WQS and two at TC during the sampling campaign, indicating a more serious O(3) pollution in Guangzhou than in Hong Kong. An observation-based model was employed to determine the ozone-precursor relationship. At both sites, O(3) production was found to be volatile organic compound (VOC)-limited, which is consistent with previous observations. Anthropogenic hydrocarbons played a key role in O(3) production, while reducing nitric oxide emissions aided the buildup of O(3) concentrations. Among VOC species, the summed relative incremental reactivity (RIR) of the top 12 compounds accounted for 89% and 85% of the total RIR at WQS and TC, respectively, indicating that local photochemical O(3) formation can be mainly attributed to a small number of VOC species. DISCUSSION AND CONCLUSIONS: A large increment in both simulated HO(2) and O(3) concentrations was achieved with additional input of hourly carbonyl data. This suggested that apart from hydrocarbons, carbonyls might significantly contribute to the O(3) production in the Pearl River Delta.

Primary hepatic peripheral T-cell lymphoma in a patient with chronic hepatitis B infection.

We report a case of primary hepatic peripheral T-cell lymphoma in a patient with hepatitis B virus-related cirrhosis. This patient presented with a solitary hepatic lesion with computed tomography and magnetic resonance imaging features that did not resemble hepatocellular carcinoma. Subsequent biopsy of the lesion revealed that it was a peripheral T-cell lymphoma. The patient was successfully treated with multi-agent chemotherapy followed by radiofrequency ablation. Although hepatocellular carcinoma is the most frequently encountered primary hepatic tumour in patients with hepatitis B virus-related cirrhosis, primary hepatic lymphoma should also be borne in mind. Nevertheless, primary hepatic lymphoma is a rare entity, and has no proven association with chronic hepatitis B infection.

Kuttner's tumour (chronic sclerosing sialadenitis) of the submandibular gland: a clinical perspective.

OBJECTIVE: To study clinical perspectives pertaining to chronic sclerosing sialadenitis, which is also known as Kuttner's tumour. DESIGN: Retrospective medical chart review. SETTING: Regional hospital, Hong Kong. PATIENTS: From February 2005 to February 2007, nine cases with Kuttner's tumour were identified from our hospital electronic database. INTERVENTIONS: They underwent submandibular sialadenectomy under either local (n=6) or general (n=3) anaesthesia. MAIN OUTCOME MEASURES: The results of preoperative ultrasonography, fine-needle aspiration cytology, and intra-operative frozen section examination were correlated with the final diagnosis. Operative morbidity was also evaluated. RESULTS: The mean age of the patients at diagnosis was 61 years; three were females. Three had bilateral submandibular swellings. Following preoperative ultrasonography in six of the patients, tumours were suspected in two, an enlarged lymph node in one, and diffuse enlargement was visualised in the other three. Six patients had preoperative fine-needle aspiration cytology; five yielded scanty acini with normal-looking ductal cells, variable degrees of infiltration by chronic inflammatory cells without granuloma admixing fibrosis. In the sixth patient, only bland-looking epithelial cells, indicative of ductal differentiation suspicious of neoplasm were noted. Intra-operative frozen section examination was conducted in three patients: chronic inflammation without evidence of carcinoma was visualised in each. Operations performed under local anaesthesia were well tolerated; only one patient endured a transient, marginal facial nerve palsy. CONCLUSIONS: Kuttner's tumour is by no means rare. When supported by ultrasonography and fine-needle aspiration cytology, an accurate diagnosis can be made preoperatively and surgery can be reserved for symptomatic cases. Submandibular sialadenectomy is a safe and effective means of treating Kuttner's tumour, and can be accomplished under local anaesthesia.

Spontaneous intra-hepatic haemorrhage in a patient with fever of unknown origin.

Polyarteritis nodosa is a systemic necrotising vasculitis that affects the small- and medium-sized arteries. Multifocal aneurysmal formation in the renal, hepatic, and mesenteric vasculature is a hallmark of this condition, and spontaneous aneurysmal rupture may occur, resulting in life-threatening haemorrhage. We describe a 42-year-old man who initially presented with fever of unknown origin. A diagnosis could not be reached at that time despite extensive investigations. The fever subsided spontaneously after 8 weeks, and the patient remained well for 6 years until he was admitted again for evaluation of fever. During his hospital stay, he developed a spontaneous massive intra-hepatic haemorrhage resulting in hepatic rupture and a haemoperitoneum. The bleeding was controlled at emergency laparotomy. An abdominal angiography demonstrated multiple microaneurysms in the hepatic and mesenteric arterial vasculature. The clinical findings suggested polyarteritis nodosa, and the source of bleeding was probably a ruptured intra-hepatic artery aneurysm.

Good enough tools for global warming policy making.

We present a simple analysis of the global warming problem caused by the emissions of CO2 (a major greenhouse gas) into the atmosphere resulting from the burning of fossil fuels. We provide quantitative tools which enable policymakers and interested citizens to explore the following issues central to the global warming problem. (i) At what rate are we permitted to continue to emit CO2 after the global average atmospheric concentration has 'stabilized' at some chosen target level? The answer here provides the magnitude of the effort, measured by the necessary total reduction of today's global (annual) emissions rate to achieve stabilization. We shall see that stabilized emissions rates for all interesting stabilized concentration levels are much lower than the current emissions rate, but these small finite values are very important. (ii) Across how many years can we spread the total effort to reduce the annual CO2 emissions rate from its current high value to the above-mentioned low and stabilized target value? The answer here provides the time-scale of the total mitigation effort for any chosen atmospheric concentration target level. We confirm the common understanding that targets below a doubling of the pre-industrial concentration create great pressure to produce action immediately, while targets above double the pre-industrial level can tolerate longer periods of inaction. (iii) How much harder is the future mitigation effort, if we do not do our share of the job now? Is it a good idea to overshoot a stabilization target? The quantitative answers here provide the penalty of procrastination. For example, the mitigation task to avoid doubling the pre-industrial level is a problem that can be addressed gradually, over a period extending more than a century, if started immediately, but procrastination can turn the effort into a much more urgent task that extends over only a few decades. We also find that overshooting target levels is a bad idea. The quality of public discourse on this subject could be much enhanced if ball-park quantitative answers to these questions were more widely known.

Intestinal tuberculosis in a regional hospital in Hong Kong: a 10-year experience.

OBJECTIVE: To study the clinical and pathological characteristics of patients with intestinal tuberculosis. DESIGN: Retrospective study. SETTING: United Christian Hospital, Hong Kong. PATIENTS: Patients with intestinal tuberculosis diagnosed between January 1995 and December 2004 inclusive. RESULTS: The median age of the 13 male and 9 female patients was 53 years (range, 12-81 years). Nineteen (86%) had a definitive diagnosis of intestinal tuberculosis confirmed by the presence of caseating granulomas and/or acid-fast bacilli in histological specimens. In three (14%) the diagnosis was based on histology revealing non-caseating granulomas and a positive response to anti-tuberculous treatment. Common symptoms included abdominal pain (82%), diarrhoea (55%), weight loss (55%), and fever (45%). Three (14%) of the patients were complicated by intestinal obstruction, and another two (9%) had intestinal perforation. Four (18%) had concomitant active pulmonary tuberculosis. The most frequently involved site was the ileocaecal region, which was affected in 19 (86%) patients. Other sites included the jejunum, ascending and sigmoid colon. The diagnosis of intestinal tuberculosis was facilitated by examination of colonoscopic biopsy specimens (11 patients), and by examination of resected surgical specimens in the remainder. Two patients died from terminal malignancy. The remainder completed anti-tuberculous therapy and responded satisfactorily. CONCLUSIONS: The diagnosis of intestinal tuberculosis is difficult due to the lack of specific signs or symptoms. Colonoscopy with ileoscopy are useful tools in the search for colonic and terminal ileal tuberculosis. Surgical exploration is reserved for equivocal cases and for those who present as emergencies.

Tuberculosis intestinal perforation during anti-tuberculosis treatment.

Intestinal perforation is an uncommon but potentially fatal complication of intestinal tuberculosis. We report on a 63-year-old HIV-negative man who developed terminal ileal perforation approximately 3.5 months following initiation of anti-tuberculous treatment for pulmonary tuberculosis and a concomitant tuberculous perianal abscess. Clinical and radiological improvements were initially evident following commencement of anti-tuberculous treatment, and the paradoxical response phenomenon was suspected. The patient subsequently underwent surgical resection of the affected bowel segment with primary anastomosis, and made an uneventful recovery. Anti-tuberculous medication was continued for another 12 months, and after a further 12 months there was no evidence of recurrent tuberculosis. This case illustrates that tuberculous intestinal perforation can develop during chemotherapy for tuberculosis. Prompt diagnosis and appropriate surgical treatment are essential to avoid morbidity and mortality.

Predictors of peptic ulcer rebleeding after scheduled second endoscopy: clinical or endoscopic factors?

BACKGROUND AND STUDY AIMS: In a previous study we demonstrated the efficacy of second-look endoscopy with therapy within 16 - 24 hours after index endoscopy in reducing major recurrent peptic ulcer bleeding. In this study, we sought to identify factors that might predict further rebleeding after this scheduled second-look endoscopy. PATIENTS AND METHODS: We studied 249 patients (181 men, 68 women) with acute bleeding peptic ulcers who were treated at the United Christian Hospital, Hong Kong from 1999 to 2002 and who underwent a scheduled second endoscopy. Those patients who developed rebleeding after the second endoscopy were evaluated, and possible predictive factors for rebleeding were analyzed using a logistic regression model. RESULTS: Of the 249 patients who underwent scheduled second-look endoscopy, 17 patients (6.8 %) developed rebleeding: seven of these patients were treated by another endoscopic therapy; ten patients required surgery. The overall mortality rate was 3.1 %. A logistic regression analysis performed on the possible predictive factors for rebleeding found that the following factors were associated with a significant risk of further rebleeding after scheduled second endoscopy: American Society of Anesthesiologists (ASA) grade III or grade IV status (odds ratio 3.81, 95 % CI 1.27 - 11.44), ulcer size greater than 1.0 cm (odds ratio 4.69, 95 % CI 1.60 - 13.80), and a finding of persistent stigmata of recent hemorrhage at the scheduled second endoscopy (odds ratio 6.65, 95 % CI 2.11 - 20.98). CONCLUSIONS: Endoscopic factors, including large ulcer size and the persistence of endoscopic stigmata of recent hemorrhage are important predictors for recurrent bleeding after scheduled second endoscopy.

Surgical management of substernal goitre: local experience.

OBJECTIVES: To examine the presentation, workup, and surgical complications of substernal goitre. DESIGN: Retrospective study. SETTING: Regional hospital, Hong Kong. PATIENTS: Twenty-four mostly elderly patients (mean age, 60.1 years) who underwent thyroidectomy for substernal goitres between 2000 and 2003 (substernal goitres were defined as those having either a caudal mass transgressing the fourth thoracic vertebra or having more than 50% of their overall mass residing within the thorax). MAIN OUTCOME MEASURES: Symptoms, histopathological diagnoses, morbidities, and complications. RESULTS: Dyspnoea was the most common symptom (n=8, 33%). Three (12.5%) patients presented with acute airway obstruction; however, 13 (54.2%) were asymptomatic apart from the presence of cervical masses. Computed tomographic scans were performed on all but two patients. Malignancy was present in 12.6% of patients, or 16.8% if occult papillary carcinoma is included. Partial or full sternotomies were performed in two (8.3%) patients. Complications included recurrent laryngeal nerve injury (n=1, 2.7% of nerves at risk), transient hypoparathyroidism (n=2, 13.3% of patients at risk), haematoma (n=1, 2.7%), pneumonia (n=1, 2.7%), and wound infection (n=1, 2.7%). There was no operative mortality or permanent hypoparathyroidism. The complication rate was significantly lower in the asymptomatic patients (P=0.033 by Fisher's exact test); clinicopathological parameters were otherwise statistically comparable between the two groups. CONCLUSIONS: There is rarely any mortality in thyroidectomy for substernal goitre, and the morbidity is also very low, especially in asymptomatic patients. In the absence of contra-indications, substernal goitre should be treated with early surgery rather than having it run the risk of acute airway distress or cancer.

Recurrent variceal bleeding in a young woman.

Congenital hepatic fibrosis is an uncommon fibrocystic disorder affecting the intrahepatic bile ducts. It has autosomal recessive inheritance. The main consequence of this condition is portal hypertension and it is often misdiagnosed as cirrhosis. Patients with congenital hepatic fibrosis usually present during childhood or early adolescence with oesophageal variceal bleeding. Portosystemic shunt surgery is the treatment of choice for these patients as the risk of postoperative hepatic encephalopathy is low. We report a patient with congenital hepatic fibrosis who presented with oesophageal variceal bleeding at the age of 16 years, initially misdiagnosed as having cryptogenic liver cirrhosis. The patient experienced two further episodes of oesophageal variceal bleeding in subsequent years. She eventually underwent portosystemic shunt surgery. One year after the operation, the shunt remained patent on Doppler ultrasonography, and there had been no further episodes of variceal bleeding post-surgery.

Effects of thyroid hormone on the development of immune system in zebrafish.

Effects of thyroxine (T4) and methimazole (MMI) on the development of the zebrafish immune system were investigated using continuous immersion treatment experiments. The effects of the treatments on thymus development were determined using computer-aided thymus morphometric analyses on in situ hybridization serial sections of the thymus while the effects on immune-related gene expression levels were monitored using quantitative real-time PCR. The findings indicate that thymus development and thymopoiesis, as indicated by thymus size, thymus Rag-1-positive region, and TCRAC expression level, were affected by T4 and MMI-treatments. With the exception of Ikaros, MMI-treated fish has lower immune-related gene expression levels, although it is not certain whether the effect resulted indirectly from the concomitant growth-retardation and/or directly from an effect on lymphopoiesis itself. The findings were comparable with those in mammalian system, thus providing the first evidence that the thyroid relationship with thymus development and lymphopoiesis is likely to be conserved from fish to higher vertebrates. It suggests the possibility of using zebrafish as a model system to investigate the molecular mechanisms involved in thyroid hormone-dependent disorders in the immune system.