The legacy of immigration policies and employment exclusion: Assessing the relationship between employment exclusions and immigrant health

Restrictive federal and state immigration policies create conditions of employment exclusion that may negatively influence the health of immigrants. In particular, these policy effects are reflected in labor market and workplace experiences that determine the types of work and employment opportunities that immigrants are able to access and pursue. This study examines the relationship between both cumulative and individual measures of employment exclusion and self-rated health and psychological distress among Asian and Latino immigrants in California, and whether this relationship is modified by legal status. We used data from the Research on Immigrant Health and State Policy (RIGHTS) study (n = 2010). We used both multivariable logistic regression and linear regression models for our analyses. For cumulative models, labor market exclusion was associated with poor health (OR = 1.21, 95% CI: 1.01, 1.46). Workplace exclusion was also associated with poor self-rated health (OR = 1.45, 95% CI: 1.15, 1.82) and increased psychological distress (β = 0.69, 95% CI: 0.31, 1.07). For individual measures of employment exclusion, settling for a job - a labor market exclusion - and working in a dangerous job and experiencing wage theft - workplace exclusions - were associated with poor health and increased psychological distress. There was no evidence that the association between employment exclusions and health varied by legal status. These findings demonstrate that the combined effect of employment exclusions is detrimental to immigrant health. To improve population health, public health researchers should continue to interrogate the policy conditions at the federal, state, and local level that exclude immigrants from employment opportunities and workplace protections.

Hong Kong consensus recommendations on the management of pancreatic ductal adenocarcinoma

This project was undertaken to develop the first set of consensus statements regarding the management of pancreatic ductal adenocarcinoma (PDAC) in Hong Kong, with the goal of providing guidance to local clinicians. A multidisciplinary panel of experts discussed issues surrounding current PDAC management and reviewed evidence gathered in the local context to propose treatment recommendations. The experts used the Delphi approach to finalise management recommendations. Consensus was defined as ≥80% acceptance among all expert panel members. Thirty-nine consensus statements were established. These statements cover all aspects of PDAC management, including diagnosis, resectability criteria, treatment modalities according to resectability, personalised management based on molecular profiling, palliative care, and supportive care. This project fulfils the need for guidance regarding PDAC management in Hong Kong. To assist clinicians with treatment decisions based on varying levels of evidence and clinical experience, treatment options are listed in several consensus statements.

Compact Yb fiber few-cycle pulse source based on precision pulse compression and shaping with an adaptive fiber Bragg grating

We generate bandwidth limited 10 µJ pulses of 92 fs pulse width using an adaptive fiber Bragg grating stretcher (FBG) in conjunction with a Lyot filter. The temperature controlled FBG is used to optimize the group delay, whereas the Lyot filter counteracts gain narrowing in the amplifier chain. Soliton compression in a hollow core fiber (HCF) allows for access to the few-cycle pulse regime. Adaptive control further enables the generation of nontrivial pulse shapes.

Limited liver resections in the posterosuperior segments: international multicentre propensity score-matched and coarsened exact-matched analysis comparing the laparoscopic and robotic approaches

Background

Limited liver resections (LLRs) for tumours located in the posterosuperior segments of the liver are technically demanding procedures. This study compared outcomes of robotic (R) and laparoscopic (L) LLR for tumours located in the posterosuperior liver segments (IV, VII, and VIII).

Methods

This was an international multicentre retrospective analysis of patients who underwent R-LLR or L-LLR at 24 centres between 2010 and 2019. Patient demographics, perioperative parameters, and postoperative outcomes were analysed; 1 : 3 propensity score matching (PSM) and 1 : 1 coarsened exact matching (CEM) were performed.

Results

Of 1566 patients undergoing R-LLR and L-LLR, 983 met the study inclusion criteria. Before matching, 159 R-LLRs and 824 L-LLRs were included. After 1 : 3 PSM of 127 R-LLRs and 381 L-LLRs, comparison of perioperative outcomes showed that median blood loss (100 (i.q.r. 40–200) versus 200 (100–500) ml; P = 0.003), blood loss of at least 500 ml (9 (7.4 per cent) versus 94 (27.6 per cent); P < 0.001), intraoperative blood transfusion rate (4 (3.1 per cent) versus 38 (10.0 per cent); P = 0.025), rate of conversion to open surgery (1 (0.8 per cent) versus 30 (7.9 per cent); P = 0.022), median duration of Pringle manoeuvre when applied (30 (20–46) versus 40 (25–58) min; P = 0.012), and median duration of operation (175 (130–255) versus 224 (155–300); P < 0.001) were lower in the R-LLR group compared with the L-LLR group. After 1 : 1 CEM of 104 R-LLRs with 104 L-LLRs, R-LLR was similarly associated with significantly reduced blood loss and a lower rate of conversion to open surgery.

Conclusion

Based on a matched analysis of well selected patients, both robotic and laparoscopic access could be undertaken safely with good outcomes for tumours in the posterosuperior liver segments.

Coherent supercontinuum shaping for multiple wavelength optimization over an octave

We shape the spectrum of an octave spanning supercontinuum from an erbium fiber laser. The group delay dispersion is controlled through the temperature profile of a chirped fiber Bragg grating. We demonstrate control of spectral broadening, switching in spectral windows, and optimizing power at six wavelengths corresponding to Yb, Ca, and Sr clock transitions, an f-2f pair, and a C-band reference for frequency transfer applications. We verify locking of the shaped f-2f beat note, and the coherence of the shaped supercontinuum by interference with an unshaped supercontinuum branch with relative frequency deviation of 10^-17 at 1 s averaging time.

Acute kidney injury following hepatectomy and its impact on long-term survival for patients with hepatocellular carcinoma

Background

Acute kidney injury (AKI) is increasingly being recognized after hepatectomy. This study aimed to identify factors predicting its occurrence and its impact on long-term outcome among patients with hepatocellular carcinoma (HCC).

Methods

This was a retrospective analysis of the incidence of AKI, factors predicting its occurrence, and its impact on patients undergoing hepatectomy between September 2007 and December 2018. A subgroup analysis included patients with histologically proven HCC.

Results

The incidence of AKI was 9.2 per cent in 930 patients. AKI was associated with increased mortality, morbidity, posthepatectomy liver failure (PHLF), and a longer hospital stay. On multivariable analysis, study period December 2013 to December 2018, diabetes mellitus, mean intraoperative BP below 72.1 mmHg, operative blood loss exceeding 377ml, high Model for End-Stage Liver Disease (MELD) score, and PHLF were predictive factors for AKI. Among 560 patients with HCC, hypertension, BP below 76.9 mmHg, blood loss greater than 378ml, MELD score, and PHLF were predictive factors. The 1-, 3-, and 5-year overall survival rates were 74.1, 59.2, and 51.6 per cent respectively for patients with AKI, and 91.8, 77.9, and 67.3 per cent for those without AKI. Corresponding 1-, 3-, and 5-year disease-free survival rates were 56.9, 42.3, and 35.4 per cent respectively in the AKI group, and 71.7, 54.5, and 46.2 per cent in the no-AKI group. AKI was an independent predictor of survival in multivariable analysis.

Conclusion

AKI is associated with longer hospital stay, and higher morbidity and mortality rates. It is also associated with shorter long-term survival among patients with HCC. To avoid AKI, control of blood loss and maintaining a reasonable BP (72–77 mmHg) during hepatectomy is important.

All-optical serrodyne frequency shifter

We describe and demonstrate a method to induce a single-sideband serrodyne-like optical frequency shift in an all-fiber device. The time-varying phase-shift is generated by cross-phase modulation in a nonlinear fiber. Unlike electro-optic based serrodyne methods, which require a high-fidelity and high-bandwidth analog electrical ramp modulation signal, the proposed optical method uses a simple pulsed pump and can be made simultaneously both low-loss and polarization-independent. We demonstrate the technique by shifting a 1550 nm optical signal 150 MHz in a 1.5 dB insertion-loss polarization-independent frequency shifter and show a pathway to multi-GHz shifting frequencies.

A Case of Hyperreactio Luteinalis Complicated With Biochemical Hyperandrogenism, Symptomatic Hyperthyroidism and Preeclampsia

Background: Hyperreactio luteinalis (HL) describes the development of multiple large ovarian cysts during pregnancy, which regress post-partum. We report a case of HL complicated with preeclampsia, biochemical hyperandrogenism and hyperthyroidism. Clinical Case: A 31-year-old non-obese Chinese woman presented at 14-week gestation for lower abdominal pain. USG showed a single fetus, multiple ovarian cysts with largest measured 39.5ml. She complained of hand tremor, palpitation but no vomiting. She had no goiter, orbitopathy or family history of thyroid disease. fT4 was 23.1pmol/L (normal: 9.8-19.8pmol/L) and TSH was <0.01mIU/L. Anti-TG, anti-TPO and anti-TSHR antibodies were negative. She had history of silent miscarriage at 6-week gestation in her first pregnancy 2 years ago, USG showed normal ovaries at that time. Carbimazole was started at 16-week gestation for fT4 26.6pmol/L (normal: 9.4-18.5pmol/L). The largest ovarian cyst increased to 130ml at 19-week gestation. Serum β-hCG was 251926IU/L (normal: 4060-165400IU/L). HL with hCG-mediated hyperthyroidism was suspected. Serum total testosterone was 22.9nmol/L (normal: 2.2-10.7nmol/L) and serum androstenedione was 70.5nmol/L (normal: 0.28-9.81nmol/L). Ferriham Gallwey score was 4. fT4 fell to 13.8pmol/L (normal: 8.8-17.0pmol/L) but TSH remained suppressed. Carbimazole was stopped at 22-week gestation with no rebound in fT4 level. She developed preeclampsia and GDM at 27-week gestation. IUGR was evident despite decreasing β-hCG level and ovarian cyst shrinkage. She had emergency LSCS for severe preeclampsia at 33-week gestation. A 1510g female baby with normal genitalia was delivered. Placenta pathology was normal. 2 days after delivery, β-hCG fell to 7081IU/L; fT4 was 9.9pmol/L (normal: 9-19pmol/L) and TSH was 0.25mIU/L (normal: 0.35-4.5mIU/L). Clinical Lessons: 1) hCG stimulates growth of ovarian stroma and androgen secretion, results in virilization in 30% of HL patients. However, only 5% of patients had hyperthyroidism. LH and hCG are structurally similar and bind to the same receptor. In contrast, hCG is a weak agonist of TSH receptor: a hCG level of more than 100000IU/L is required to cause clinical thyrotoxicosis. Since 30% of HL patients have normal hCG level, this may explain the lower incidence of hyperthyroidism than hyperandrogenism. 2) Degree of maternal virilization does not correlate with testosterone level. Study by Condic et al. found significant overlap of testosterone levels in women with (13.7-197.5nmol/l) and without (6.2-37.3nmol/l) virilization. Genetic polymorphism of androgen receptor may account for the different clinical manifestation. Fetal virilization is rare, due to protective role of placental aromatase. 3) Elevated hCG in apparently “normal” singleton pregnancy may be due to poor placentation in early gestation and is a risk factor for preeclampsia and IUGR in HL patients.

Robotic versus laparoscopic hepatectomy: application of the difficulty scoring system

BACKGROUND

The development of robotic system may help to relieve the difficulties encountered during laparoscopic hepatectomy. A difficulty scoring system (DSS) was developed to assess the difficulty of various laparoscopic liver resection procedures. The aim of this study is to explore if the DSS is applicable in robotic hepatectomy and to compare the outcomes of robotic hepatectomy and laparoscopic hepatectomy among different difficulty levels.

METHODS

Clinical data from all consecutive patients who underwent robotic and conventional laparoscopic hepatectomy at the Prince of Wales Hospital, Hong Kong, were prospectively collected and reviewed. The difficulty level of operations was graded using the DSS. Perioperative outcomes of robotic and conventional laparoscopic hepatectomy were compared at each difficulty level.

RESULTS

A total of 107 and 94 patients underwent robotic and laparoscopic hepatectomy during the study period, respectively. Among them, 16 and 2 patients were operated for recurrent pyogenic cholangitis, respectively, and were excluded because no mark for tumour location can be assigned. For robotic hepatectomy, a higher DSS was significantly correlated with higher minor complication rate (p = 0.001), more intraoperative blood loss (p = 0.002), longer operation time (p < 0.001) and longer post-operative hospital stay (p < 0.001). The mean DSS scores of robotic and laparoscopic hepatectomy were 4.5 and 3.6, respectively. (p = 0.004). For cases with low (DSS 1-3) and intermediate (DSS 4-6) difficulty level, there was no significant difference in operative blood loss, operation time and overall complications rate. Only 2 cases (2.2%) with high difficulty level were operated with laparoscopic approach while 20% of patients operated with robotic approach had DSS > 6.

CONCLUSIONS

DSS significantly correlated with surgical outcomes in patient who underwent robotic hepatectomy. Perioperative outcomes following robotic and conventional laparoscopic hepatectomy were similar in cases with low and intermediate difficulty. However, robotic system allowed minimally invasive approach in cases with higher difficulty level.

Enhanced recovery after surgery for liver resection

INTRODUCTION

Enhanced recovery after surgery (ERAS) reduces postoperative length of hospital stay and patient stress response to liver surgery. The aim of the present study was to evaluate the efficacy and feasibility of an ERAS programme for liver resection.

METHODS

A multidisciplinary ERAS protocol was implemented for both open and laparoscopic liver resection in a tertiary hospital in Hong Kong. The clinical outcomes of patients who underwent liver resection and underwent the ERAS perioperative programme were compared with those who received a conventional perioperative programme between September 2015 and July 2016. Propensity score matching analysis was used to minimise background differences.

RESULTS

A total of 20 patients who underwent liver resection were recruited to the ERAS programme. Their clinical outcomes were compared with another 20 patients who received hepatectomy under a conventional perioperative programme after propensity score matching. The ERAS programme was associated with a significantly shorter length of hospital stay (P=0.033) without an increase in complication rates in patients who underwent open liver resection. There was no such significant association in patients who underwent laparoscopic liver resection. No patients required readmission in this cohort.

CONCLUSIONS

The ERAS perioperative programme for liver resection is safe and feasible. It significantly shortened the hospital stay after open liver resection but not after laparoscopic liver resection.

Rovibrational quantum state resolution of the C60 fullerene

The unique physical properties of buckminsterfullerene, C₆₀, have attracted intense research activity since its original discovery. Total quantum state-resolved spectroscopy of isolated C₆₀ molecules has been of particularly long-standing interest. Such observations have, to date, been unsuccessful owing to the difficulty in preparing cold, gas-phase C₆₀ in sufficiently high densities. Here we report high-resolution infrared absorption spectroscopy of C₆₀ in the 8.5-micron spectral region (1180 to 1190 wave number). A combination of cryogenic buffer-gas cooling and cavity-enhanced direct frequency comb spectroscopy has enabled the observation of quantum state-resolved rovibrational transitions. Characteristic nuclear spin statistical intensity patterns confirm the indistinguishability of the 60 carbon-12 atoms, while rovibrational fine structure encodes further details of the molecule's rare icosahedral symmetry.

Traumatic Liver Injury in Hong Kong: The Management Strategy and Outcome

Introduction

Management of liver injury is challenging and evolving. The aim of this article is to review the outcome of traumatic liver injury in Chinese people in Hong Kong.

Materials & methods

Records of 40 patients with hepatic injury who received treatment at the Prince of Wales Hospital between December 2000 and May 2005 were reviewed. Demographic data, severity of liver injury, Injury Severity Score (ISS), haemodynamic status and Glasgow Coma Scale (GCS) score on admission, investigations made, concomitant injuries, management scheme, and outcome of patients were analysed.

Results

There were 23 male and 17 female patients with a mean age of 31.3 (SD=15.4) years. Road traffic accident was the most common injury mechanism (65%). Half of the patients were treated by non-operative management (NOM). None of them required surgery during subsequent management. Patients in the operative management (OM) group had a significantly higher ISS (p=0.026), but there was no significant difference in the mortality rate between the OM and NOM groups. Patients with stable haemodynamic status and who were treated non-operatively had a significantly shorter hospital stay (p=0.006). High grade liver injury (OR=8.0, 95% CI=1.2 to 53.8, p=0.03) and ISS greater than 25 (OR=21.6, 95% CI=2.0 to 225.3, p=0.01) were independent risk factors for mortality on multivariate analysis.

Conclusions

Non-operative management of liver injury can be safely accomplished in haemodynamically stable patients, with the possible benefit of a shorter hospital stay.

Midinfrared frequency comb by difference frequency of erbium and thulium fiber lasers in orientation-patterned gallium phosphide

We generate over 60 mW of pulses with wavelengths from 6 to 11 micrometers by difference frequency mixing between erbium and thulium fiber amplifiers in orientation-patterned GaP with a photon conversion efficiency of 0.2. By stabilizing the repetition rate of the shared oscillator and adding a frequency shifter to one arm, the output becomes a frequency comb with tunable carrier envelope offset.

Harmonic generation in solids with direct fiber laser pumping

High harmonic generation in solids presents the possibility for bringing attosecond techniques to semiconductors and a simple source for frequency comb spectroscopy in the vacuum ultraviolet. We generate up to the seventh harmonic of a Tm fiber laser by focusing in silicon or zinc oxide. The harmonics are strong and stable, with no indication of material damage. Calculations show the potential for generating nineteenth harmonic photons at 12 eV photons of energy.

Three-photon absorption in optical parametric oscillators based on OP-GaAs

We report on, to the best of our knowledge, the first singly resonant (SR), synchronously pumped optical parametric oscillator (OPO) based on orientation-patterned gallium arsenide (OP-GaAs). Together with a doubly resonant (DR) degenerate OPO based on the same OP-GaAs material, the output spectra cover 3 to 6 μm within ∼3  dB of relative power. The DR-OPO has the highest output power reported to date from a femtosecond, synchronously pumped OPO based on OP-GaAs. We observed strong three-photon absorption with a coefficient of 0.35±0.08  cm³/GW² for our OP-GaAs sample, which limits the output power of these OPOs as mid-IR light sources. We present a detailed study of the three-photon loss on the performance of both the SR- and DR-OPOs, and compare them to those without this loss mechanism.

Three-photon absorption in optical parametric oscillators based on OP-GaAs

We report on, to the best of our knowledge, the first singly resonant (SR), synchronously pumped optical parametric oscillator (OPO) based on orientation-patterned gallium arsenide (OP-GaAs). Together with a doubly resonant (DR) degenerate OPO based on the same OP-GaAs material, the output spectra cover 3 to 6 μm within ∼3  dB of relative power. The DR-OPO has the highest output power reported to date from a femtosecond, synchronously pumped OPO based on OP-GaAs. We observed strong three-photon absorption with a coefficient of 0.35±0.08  cm³/GW² for our OP-GaAs sample, which limits the output power of these OPOs as mid-IR light sources. We present a detailed study of the three-photon loss on the performance of both the SR- and DR-OPOs, and compare them to those without this loss mechanism.

CT features of mediastinal lymphangiohemangioma associated with superior vena cava ectasia: A case report

We present a case of mediastinal mesenchymal tumor in a 53-year-old woman with a 1-month history of chest tightness. A histological diagnosis of lymphangiohemangioma was obtained by excisional biopsy. CT findings are reported with emphasis on its association with intratumoral superior vena cava ectasia.

Fourier transform and Vernier spectroscopy using an optical frequency comb at 3-5.4 μm

We present a versatile mid-infrared frequency comb spectroscopy system based on a doubly resonant optical parametric oscillator tunable in the 3-5.4 μm range and two detection methods: a Fourier transform spectrometer (FTS) and a continuous-filtering Vernier spectrometer (CF-VS). Using the FTS with a multipass cell, we measure high precision broadband absorption spectra of CH₄ at 3.3 μm and NO at 5.25 μm, the latter for the first time with comb spectroscopy, and we detect atmospheric species (CH₄, CO, CO₂, and H₂O) in air in the signal and idler ranges. Multiline fitting yields minimum detectable concentrations of 10-20  ppb Hz^-1/2 for CH₄, NO, and CO. For the first time in the mid-infrared, we perform CF-VS using an enhancement cavity, a grating, and a single detector, and we measure the absorption spectrum of CH₄ and H₂O in ambient air at ∼3.3  μm, reaching a 40 ppb concentration detection limit for CH₄ in 2 ms.

Simultaneous multi-frequency topological edge modes between one-dimensional photonic crystals

We show theoretically that, in the limit of weak dispersion, one-dimensional binary centrosymmetric photonic crystals can support topological edge modes in all photonic bandgaps. By analyzing their bulk band topology, these "harmonic" topological edge modes can be designed in a way that they exist at all photonic bandgaps opened at the center of the Brillouin zone, at all gaps opened at the zone boundaries, or both. The results may suggest a new approach to achieve robust multi-frequency coupled modes for applications in nonlinear photonics, such as frequency upconversion.

Self-referenced, accurate and sensitive optical frequency comb spectroscopy with a virtually imaged phased array spectrometer

We present a cavity-enhanced direct optical frequency comb spectroscopy system with a virtually imaged phased array (VIPA) spectrometer and either a dither or a Pound-Drever-Hall (PDH) locking scheme used for stable transmission of the comb through the cavity. A self-referenced scheme for frequency axis calibration is shown along with an analysis of its accuracy. A careful comparison between both locking schemes is performed based on near-IR measurements of the carbon monoxide ν=3←0 band P branch transitions in a gas sample with known composition. The noise-equivalent absorptions (NEA) for the PDH and dither schemes are 9.9×10(-10) cm(-1) and 5.3×10(-9) cm(-1), respectively.

Midinfrared frequency comb from self-stable degenerate GaAs optical parametric oscillator

We pump a degenerate frequency-divide-by-two optical parametric oscillator (OPO) based on orientation-patterned GaAs with a stable Tm frequency comb at 2 micrometer wavelength and measure the OPO comb offset frequency and linewidth. We show frequency division by two with sub-Hz relative linewidth of the comb teeth. The OPO thermally self-stabilizes and oscillates for nearly an hour without any active control.

Antiviral therapy improves post-hepatectomy survival in patients with hepatitis B virus-related hepatocellular carcinoma: a prospective-retrospective study

BACKGROUND

The effect of antiviral therapy on the post-hepatectomy long-term survival in patients with hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC) remains uncertain.

AIM

To evaluate the effect of antiviral therapy on post-hepatectomy survival and recurrence in patients with HBV-related HCC.

METHODS

This was a prospective-retrospective study of a total of 404 patients who underwent hepatectomy for HBV-related HCC in a tertiary academic hospital. Data on patient and tumour characteristics, tumour recurrence, treatment for recurrence and survival were compared between antiviral and no antiviral groups.

RESULTS

Patient's and tumour characteristics were comparable between the two groups, except a higher proportion of patients with cirrhosis in the antiviral group. With a mean follow-up time of 52.4 months, antiviral group had a better 5-year overall survival (66.7% vs. 56.0%, P = 0.001) while there was no significant difference in the 5-year disease-free survival (44.7% vs. 38.1%, P = 0.166). Use of antiviral therapy was associated with better liver function reserve at the time of recurrence and a greater proportion of patients could receive curative treatment for recurrence (38.5% vs. 24.3%, P = 0.041). There was no significant different in the hazard ratios of patients who started antiviral therapy before or after operation (P = 0.054).

CONCLUSIONS

Use of antiviral therapy improves the long-term post-hepatectomy survival in patients with HBV-related HCC. With a better liver function reserve at the time of recurrence, a greater proportion of patients in antiviral group could receive curative treatment for recurrence.

An uncommon cause of Cushing's syndrome in a 70-year-old man

Cushing's syndrome due to exogenous steroids is common, as about 1% of the general populations use exogenous steroids for various indications. Although endogenous Cushing's syndrome due to ectopic adrenocorticotropic hormone from a pancreatic neuroendocrine tumour is rare, a correct and early diagnosis is important. The diagnosis and management require high clinical acumen and collaboration between different specialists. We report a case of ectopic adrenocorticotropic hormone Cushing's syndrome due to pancreatic neuroendocrine tumour with liver metastasis. Early recognition by endocrinologists with timely surgical resection followed by referral to oncologists led to a favourable outcome for the patient up to 12 months after initial presentation.

Alignment dependent enhancement of the photoelectron cutoff for multiphoton ionization of molecules

The multiphoton ionization rate of molecules depends on the alignment of the molecular axis with respect to the ionizing laser polarization. By studying molecular frame photoelectron angular distributions from N(2), O(2), and benzene, we illustrate how the angle-dependent ionization rate affects the photoelectron cutoff energy. We find alignment can enhance the high energy cutoff of the photoelectron spectrum when probing along a nodal plane or when ionization is otherwise suppressed. This is supported by calculations using a tunneling model with a single ion state.

Midinfrared frequency combs from coherent supercontinuum in chalcogenide and optical parametric oscillation

We observe the coherence of the supercontinuum generated in a nanospike chalcogenide-silica hybrid waveguide pumped at 2 μm. The supercontinuum is shown to be coherent with the pump by interfering it with a doubly resonant optical parametric oscillator (OPO) that is itself coherent with the shared pump laser. This enables coherent locking of the OPO to the optically referenced pump frequency comb, resulting in a composite frequency comb with wavelengths from 1 to 6 μm.

Late presentation of simple virilising 21-hydroxylase deficiency in a Chinese woman with Turner's syndrome

Classical congenital adrenal hyperplasia due to 21-hydroxylase deficiency is a well-known disorder of sexual development (previously known as ambiguous genitalia) in genotypic female neonates. We report on a 66-year-old Chinese, brought up as male, with a simple virilising form of congenital adrenal hyperplasia associated with Turner's syndrome (karyotype 45,X/47,XXX/46,XX). His late presentation was recognised due to his exceptionally short stature and persistent sexual ambiguity. His condition was only brought to medical attention as he developed a huge abdominal mass, which later turned out to be a benign ovarian mucinous cyst. It is therefore important to look out for co-existing congenital adrenal hyperplasia in patients with Turner's syndrome and virilisation, after the presence of Y chromosome material has been excluded.

Mid-infrared supercontinuum generation in As2S3-silica "nano-spike" step-index waveguide

Efficient generation of a broad-band mid-infrared supercontinuum spectrum is reported in an arsenic trisulphide waveguide embedded in silica. A chalcogenide "nano-spike", designed to transform the incident light adiabatically into the fundamental mode of a 2-mm-long uniform section 1 µm in diameter, is used to achieve high launch efficiencies. The nano-spike is fully encapsulated in a fused silica cladding, protecting it from the environment. Nano-spikes provide a convenient means of launching light into sub-wavelength scale waveguides. Ultrashort (65 fs, repetition rate 100 MHz) pulses at wavelength 2 µm, delivered from a Tm-doped fiber laser, are launched with an efficiency ~12% into the sub-wavelength chalcogenide waveguide. Soliton fission and dispersive wave generation along the uniform section result in spectral broadening out to almost 4 µm for launched energies of only 18 pJ. The spectrum generated will have immediate uses in metrology and infrared spectroscopy.

Carrier envelope offset frequency of a doubly resonant, nondegenerate, mid-infrared GaAs optical parametric oscillator

We measure the carrier envelope offset (CEO) frequency of the mid-infrared frequency comb (wavelength tunable between 3 and 6 μm) from a doubly resonant nondegenerate synchronously pumped optical parametric oscillator (SPOPO) as a function of the CEO frequency of the Tm-fiber pump laser. We show that the CEO frequency of the SPOPO signal wave is a linear function of the CEO frequency of the pump laser, with a slope determined by the signal to pump center-frequency ratio.

Ultrasonographic findings in eyes with retinopathy of prematurity in malaysia

RetCam is an excellent screening tool for the detection of retinopathy of prematurity (ROP). However, affordability is a barrier when adopting the use of RetCam in developing countries. We aimed to describe different stages of ROP using ultrasonographic B-scan and to evaluate the association between funduscopic examinations and ultrasonographic B-scan findings in premature neonates with ROP in Malaysia. A descriptive cross sectional study was conducted in 90 eyes of 47 premature neonates with different stages of ROP in three tertiary hospitals in Malaysia. Experienced ophthalmologists performed detailed funduscopic examinations using binocular indirect ophthalmoscopy (BIO). A masked examiner performed a 10 MHz ultrasonographic B-scan evaluation with 12 meridian position images within 48 hours of clinical diagnosis. Data from the clinical examination and ultrasonographic findings were collected and analysed. We recruited 37 eyes (41.1%) with stage 1 ROP, 29 eyes (32.3%) with stage 2, 18 eyes (20.0%) with stage 3, and 3 eyes (3.3%) with stages 4 and 5 based on the clinical assessment. Ultrasonography correctly identified 3 (8.1%) stage 1 eyes, 17 (58.6%) stage 2 eyes, 13 (72.2%) stage 3 eyes, and 3 each (100%) of the stage 4 and 5 eyes. There was a significant association between the funduscopic signs and the ultrasound findings for stage 2 ROP and above (Fisher's exact test, p <0.001). In conclusion, all stages of ROP were detected and described with a 10 MHz ultrasonic B-scan system. A significant association was observed between funduscopic signs and ultrasonographic findings in premature Malaysian neonates with stage 2 ROP and above.

Randomized clinical trial of open hepatectomy with or without intermittent Pringle manoeuvre

BACKGROUND

The intermittent Pringle manoeuvre (IPM) is commonly applied during liver resection. Few randomized trials have addressed its effectiveness in reducing blood loss and the results have been conflicting. The present study investigated the hypothesis that IPM could reduce blood loss during liver resection by 50 per cent.

METHODS

Between May 2008 and April 2011, patients who underwent elective open hepatectomy were randomized into an IPM or no Pringle manoeuvre (NPM) group and stratified according to the presence or absence of cirrhosis. Data on demographics, type of hepatectomy, operative blood loss, duration of operation, mortality, morbidity and postoperative liver function were recorded and analysed. The primary endpoint was operative blood loss.

RESULTS

There were 63 patients in each group. Median (range) operative blood loss was 370 (50-3600) ml in the IPM group versus 335 (40-3160) ml in the NPM group (P = 1·000). There were no differences in blood loss in different phases of the operation, blood loss per area of liver transected or blood transfusion rate, nor in total duration of operation or liver transection time. Postoperative serum alanine aminotransferase levels were higher in the IPM group (P < 0·001). There were more postoperative complications in the IPM group (41 versus 24 per cent; P = 0·036).

CONCLUSION

The IPM did not reduce blood loss, but was associated with raised levels of postoperative liver parenchymal enzymes and more complications.

REGISTRATION NUMBER

NCT00730743 (http://www.clinicaltrials.gov).

Prevalence of undiagnosed diabetes mellitus and cardiovascular risk factors in Hong Kong professional drivers

AIMS

To investigate the prevalence of undiagnosed diabetes mellitus (DM) and cardiovascular risk factors among professional drivers in Hong Kong.

METHODS

Chinese professional drivers with no history of DM were invited to complete a questionnaire on their health status, followed by taking their body measurements, fasting blood glucose (FG) and lipids. 75g OGTT were performed when FG≥5.6 to <7.0mmol/L.

RESULTS

Of these 3376 drivers (male 92.6%, mean age 50.9±7.6 years), the prevalence of undiagnosed DM, prediabetes, and metabolic syndrome was 8.1% (272/3376, 95% CI 7.1-9.0%), 10.0% (337/3376, 95% CI 9.0-11.0%) and 26.8% (904/3376, 95% CI 25.3-28.3%) respectively, while the corresponding WHO Standard Population age-standardized prevalence was 7.8%, 9.0% and 24.7% respectively. Many of them were obese (51.2%), had hypertension (57.0%) and high cholesterol (58.7%), and a third had hypertriglyceridaemia (34.9%) and low HDL-cholesterol (29.3%). Their median working hours were 60.0 (IQR 14)h. Majority had exercise <1h/week (56.0%) and ate out ≥6times/week (54.9%).

CONCLUSIONS

Hong Kong professional drivers have higher prevalence of undiagnosed DM, cardiovascular risk factors and metabolic syndrome than the general population. Therefore, health care measures targeting against them should be taken to prevent and detect DM and cardiovascular diseases.

Surgical ablation of hepatocellular carcinoma with 2.45-GHz microwave: a critical appraisal of treatment outcomes

OBJECTIVE

To evaluate the efficacy and safety of a new generation of 2.45-GHz microwave to ablate hepatocellular carcinoma by surgical approach. DESIGN; Case series with prospective follow-up.

SETTING

A university teaching hospital in Hong Kong.

PATIENTS

From March 2009 to January 2011, 26 consecutive patients (19 men and 7 women) with a median age of 63 (range, 49-79) years with hepatocellular carcinoma were recruited. Five (19%) of the patients had recurrent hepatocellular carcinoma after previous treatment.

INTERVENTION

Microwave ablation for hepatocellular carcinomas (one tumour, n=24; two tumours, n=2) using a laparoscopic (n=16) or open approach (n=10).

MAIN OUTCOME MEASURES

Operative mortality and morbidity, rate of incomplete ablation, recurrence rate, and survival rate.

RESULTS

The median tumour diameter was 3.8 cm (range, 2.0-6.0 cm). Complications occurred in five (19%) of the patients; only one was ablation-related, and there was no operative mortality. One (4%) of the patients experienced incomplete ablation. Recurrent tumours were noted in 11 (42%) of the patients (5 were local, 2 were remote, and 4 were multifocal) after a median follow-up of 14 (range, 4-26) months. The failure rate for local disease control was 23%, and was 14% if patients with recurrent hepatocellular carcinoma were excluded. All but one patient survived until the time of censorship. The mean survival was 25 (standard deviation, 1) months.

CONCLUSION

This new-generation microwave technique is safe and effective for local ablation of hepatocellular carcinoma. It is a valuable treatment option for patients who are not candidates for hepatectomy.

Single-incision laparoscopic cholecystectomy: from four wounds to one

OBJECTIVE

To review the initial results and surgical outcomes of single-incision laparoscopic cholecystectomy.

DESIGN

Prospective case series.

SETTING

A university teaching hospital and a regional hospital in Hong Kong.

PATIENTS

All patients undergoing single-incision laparoscopic cholecystectomy from August 2009 to March 2011.

RESULTS

Fifty patients underwent single-incision laparoscopic cholecystectomy during the study period. The indications for surgery included symptomatic gallstones (n=43) and gallbladder polyps (n=7). The mean operating time was 78 (standard deviation, 24) minutes. Forty-five of the patients successfully underwent single-incision laparoscopic cholecystectomy, giving a success rate of 90%. In the remaining five patients, additional working ports were constructed to obtain better exposure and dissection around Calot's triangle. On comparing the results of the initial 25 cases to the subsequent 25 cases, in the latter group the operating time was significantly shorter (86 vs 71 minutes; P=0.02), and the success rate was higher (80% vs 100%; P=0.05). During the median follow-up period of 6.8 months, four patients had complications, which included: postoperative urinary retention (n=2), one each with a haematoma and an incisional hernia. No patient endured bile duct injury, postoperative bile leakage, or haemorrhage in our series.

CONCLUSION

Single-incision laparoscopic cholecystectomy is feasible and safe for treatment of uncomplicated gallbladder diseases. There was a reduction in the operating time and increase in success rate with accumulation of experience. Nevertheless, surgeons should be cautious about the potential risks of this new technique.

A randomized-controlled trial to investigate the effects of rivoglitazone, a novel PPAR gamma agonist on glucose-lipid control in type 2 diabetes

AIM

To examine the efficacy, safety and tolerability of rivoglitazone, a novel thiazolidinedione (TZD), and explore its effects on glucose and lipid control compared to placebo and pioglitazone in Chinese type 2 diabetic patients who are treatment naÏve or treated with a single oral blood glucose-lowering drug.

METHODS

This was a double-blind, randomized, placebo- and active-controlled study. A total of 287 Chinese type 2 diabetic patients with suboptimal glycaemic control (defined as HbA1c ≥6.5 to <10% and fasting plasma glucose ≥7 to ≤15 mmol/l) were enrolled. One hundred and seventy-four eligible patients were randomized into one of the five treatment arms for 12 weeks: placebo, pioglitazone 30 mg daily, rivoglitazone of dose 0.5, 1.0 or 1.5 mg daily. In a full set analysis, we used analysis of covariance to compare the primary endpoint defined as change in HbA1c from baseline to week 12/last observation carried forward in the rivoglitazone group at each dose level with the placebo group.

RESULTS

Changes in HbA1c were -0.11% in the 0.5-mg group; -0.22% in the 1-mg group and -0.17% in the 1.5-mg rivoglitazone group; -0.06% in the 30-mg pioglitazone group and 0.61% in the placebo group. Compared to placebo, changes were significant in all active treatment groups (all p < 0.05). Increase in high-density lipoprotein cholesterol and decrease in triglyceride were observed in the rivoglitazone 1 and 1.5 mg groups, respectively, compared to placebo from baseline to week 12 (p < 0.05). Drug-related oedema was reported in eight patients (7.7%) in all rivoglitazone groups compared to six patients (16.2%) in the pioglitazone group and one patient (3.0%) in the placebo group.

CONCLUSIONS

Rivoglitazone is an efficacious, safe and well-tolerated TZD which improved glycaemic control in Chinese type 2 diabetic patients up to 3 months.

Molecular analysis of congenital adrenal hyperplasia due to 21-hydroxylase deficiency in Hong Kong Chinese patients

BACKGROUND

Congenital adrenal hyperplasia (CAH) caused by 21-hydroxylase deficiency (21OHD) is an autosomal recessive disorder due to mutation in the CYP21A2 gene.

OBJECTIVE

To elucidate the genetic basis of 21-hydroxylase-deficient CAH in Hong Kong Chinese patients.

PATIENTS AND METHODS

Mutational analysis of the CYP21A2 gene was performed on 35 Hong Kong Chinese patients with 21OHD using direct DNA sequencing and multiplex ligation-dependent probe amplification (MLPA).

RESULTS

The genetic findings of 21 male and 14 female patients are the following: c.293-13A/C>G (intron 2 splice site; 20 alleles), p.I172N (13), p.R356W (7), p.Q318X (4). A total of 20 mutant alleles contained gross deletion/conversion of all or part of the CYP21A2 gene. A novel mutation, c.1367delA (p.D456fs), was detected in one patient. One patient had only a heterozygous mutation detected. Out of 35 patients, 16 would have been incorrectly genotyped if either DNA sequencing or MLPA alone was used for molecular analysis.

CONCLUSIONS

The frequency of various mutations in the studied patients differs from those reported in other Asian populations. Gross deletion/conversion accounts for nearly one-third of the genetic defects. Therefore, laboratories must include methods for detecting point mutations as well as gross deletions/conversions to avoid misinterpretation of genotype. Genotyping has increasingly been proven to be a useful tool for supplementing, if not replacing, hormonal profiling for the diagnosis of 21OHD.

Risk of development of diabetes mellitus in Chinese women with persistently impaired glucose tolerance after gestational diabetes

OBJECTIVES

To estimate the cumulative incidence for the development of diabetes mellitus in Chinese women with persistently impaired glucose tolerance after gestational diabetes, and evaluate putative risk factors.

DESIGN

Historical cohort study.

SETTING

A regional hospital in Hong Kong.

PATIENTS

Women with postpartum impaired glucose tolerance (as confirmed by a 75-gram oral glucose tolerance test 6 weeks after delivery) seen between January 2000 and December 2006.

RESULTS

After a mean follow-up period of 52 (standard deviation, 22; range, 12-106) months, 47 (20%) of the 238 women converted to diabetes mellitus. Concomitant postpartum impaired fasting plasma glucose levels increased the risk of future diabetes mellitus by 3.5-fold (95% confidence interval, 1.7-7.0; P=0.001) when compared to those with postpartum impaired glucose tolerance only. Based on multivariate analysis, only antepartum and postpartum fasting plasma glucose levels predicted future development of diabetes mellitus. At 1 year after delivery in 95/159 (60%) of the women, glucose tolerance regressed to normal, while in only 9/159 (6%) it progressed to diabetes mellitus. At this stage, 29% of those with impaired glucose regulation (impaired glucose tolerance, impaired fasting glucose or both) compared to 2% of those whose glucose tolerance reverted to normal developed diabetes mellitus upon subsequent follow-up (P<0.001). In all, 24/159 (15%) fulfilled the definition of metabolic syndrome and its presence was associated with 4.7-fold increased risk of future diabetes mellitus (95% confidence interval, 1.7-13.4; P=0.004).

CONCLUSIONS

Women with persistent postpartum impaired glucose tolerance after gestational diabetes have a high risk of developing diabetes mellitus. However, a significant proportion of these women regress to normal glucose tolerance 1 year after delivery, and their risk of progression to diabetes mellitus is lower than those with persistent impaired glucose regulation. Therefore, women with a history of gestational diabetes, particularly those with persistent glucose intolerance 6 weeks and 1 year after delivery, should have regular surveillance for the development of diabetes mellitus.

Testicular signaling is the potential target of perfluorooctanesulfonate-mediated subfertility in male mice

Perfluorooctanesulfonate (PFOS) was produced and used by various industries and in consumer products. Because of its persistence, it is ubiquitous in air, water, soil, wildlife, and humans. Although the adverse effects of PFOS on male fertility have been reported, the underlying mechanisms have not yet been elucidated. Here, for the first time, the effects of PFOS on testicular signaling, such as gonadotropin, growth hormone, insulin-like growth factor, and inhibins/activins were shown to be directly related to male subfertility. Sexually mature 8-wk-old CD1 male mice were administered by gavages in corn oil daily with 0, 1, 5, or 10 mg/kg PFOS for 7, 14, or 21 days. Serum concentrations of testosterone and epididymal sperm counts were significantly lower in the mice after 21 days of the exposure to the highest dose compared with the controls. The expression levels of testicular receptors for gonadotropin, growth hormone, and insulin-like growth factor 1 were considerably reduced on Day 21 in mice exposed daily to 10 or 5 mg/kg PFOS. The transcript levels of the subunits of the testicular factors (i.e., inhibins and activins), Inha, Inhba, and Inhbb, were significantly lower on Day 21 of daily exposure to 10, 5, or 1 mg/kg PFOS. The mRNA expression levels of steroidogenic enzymes (i.e., StAR, CYP11A1, CYP17A1, 3beta-HSD, and 17beta-HSD) were notably reduced. Therefore, PFOS-elicited subfertility in male mice is manifested as progressive deterioration of testicular signaling.

Amiodarone-induced thyroid dysfunction in the Hong Kong Chinese population

OBJECTIVE

To determine the frequency, risk factors, clinical features, and management of amiodarone-induced thyroid dysfunctions.

DESIGN

Retrospective study.

SETTING

A regional hospital in Hong Kong.

PATIENTS

Patients who had been prescribed amiodarone for at least 6 months from 1 October 2005 to 30 September 2007.

RESULTS

A total of 390 patients (mean age, 70 years; standard deviation, 9 years; 54% male) with a median follow-up of 43 (interquartile range, 25-69) months were studied. Hypothyroidism developed in 87 (22%) of the patients (mean age, 72 years; standard deviation, 7 years; 56% male) and thyrotoxicosis in 24 (6%) of the patients (65 years; 11 years; 54% male). Increased baseline thyrotropin (thyroid-stimulating hormone) level appeared to be predictive of amiodarone-induced hypothyroidism, in which a thyroid-stimulating hormone level of 4 mIU/L or above was associated with a 4.7-fold increase in the risk (95% confidence interval, 1.9-11.7; P<0.001). Compared with those who remained euthyroid on amiodarone, thyrotoxicosis developed in younger patients. In these patients, the classical symptoms of thyroid dysfunction were frequently absent, although worsening of underlying arrhythmias, their cardiac condition, weight loss, and over-warfarinisation were suggestive of amiodarone-induced thyrotoxicosis. In both amiodarone-induced thyrotoxicosis and hypothyroidism, the disease course was benign. Patients with the former showed a good response to anti-thyroid drugs and steroid therapy.

CONCLUSIONS

Amiodarone-induced thyroid dysfunction is common among our population. As the clinical presentations are usually vague and atypical, regular biochemical monitoring of thyroid function is warranted, particularly in patients with elevated baseline thyroid-stimulating hormone level. The disease course of amiodarone-induced thyrotoxicosis is usually benign and remits with timely administration of anti-thyroid medications, with or without corticosteroids.

Direct mid-infrared femtosecond pulse shaping with a calomel acousto-optic programmable dispersive filter

Direct amplitude and phase shaping of mid-infrared femtosecond pulses is realized with a calomel-based acousto-optic programmable dispersive filter transparent between 0.4 and 20 μm. The shaped pulse electric field is fully characterized with high accuracy, using chirped-pulse upconversion and time-encoded arrangement spectral phase interferometry for direct electric field reconstruction techniques. Complex mid-infrared pulse shapes at a center wavelength of 4.9 μm are generated with a spectral resolution of 14 cm(-1), which exceeds by a factor of 5 the reported experimental resolutions of calomel-based filters.

The analgesic efficacy of continuous wound instillation with ropivacaine after open hepatic surgery

The analgesic efficacy of continuous local anaesthetic wound instillation after open hepatic surgery was evaluated. Forty-eight patients scheduled for elective liver surgery were assigned to receive either ropivacaine 0.25% or saline infusion at 4 ml.h(-1) for 68 h via two multi-orifice indwelling catheters placed within the musculo-fascial layer before skin closure; plasma ropivacaine concentrations were measured during the infusion. Supplemental analgesia was provided by intravenous patient-controlled analgesia morphine. Patients in the ropivacaine group had decreased mean (SD) total morphine consumption (58 (30) mg vs 86 (44) mg, p = 0.01) and less pain at rest as well as after spirometry at 4, 12, 24, 48 and 72 h postoperatively (p < 0.01). Forced vital capacity was reduced postoperatively in both groups, but the reduction was greater in the saline group at 12 and 24 h (p = 0.03). The mean plasma concentration of ropivacaine increased to 2.05 (0.78) μg.ml(-1) at the point when the infusion was terminated.

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.

A community-acquired methicillin-resistant Staphylococcus aureus liver abscess

Liver abscesses caused by community-acquired methicillin-resistant Staphylococcus aureus are rarely reported. We report such a case in a 25-year-old man who presented with an intermittent fever. He had a history of prolonged antibiotic use for acne and skin abscesses. The liver abscess was successfully treated with percutaneous drainage and a prolonged course of linezolid. To our knowledge, this is the first reported case of a community-acquired methicillin-resistant Staphylococcus aureus liver abscess in Hong Kong, demonstrating the increasing threat posed by this multidrug-resistant organism. This case also suggests that a different epidemiology and route of infection may apply to community-acquired methicillin-resistant Staphylococcus aureus liver abscesses in contrast to the more common pyogenic liver abscesses.

Suppression of perturbed free-induction decay and noise in experimental ultrafast pump-probe data

We apply a Fourier filtering technique for the global removal of coherent contributions, like perturbed free-induction decay, and noise, to experimental pump-probe spectra. A further filtering scheme gains access to spectra otherwise only recordable by scanning the probe's center frequency with adjustable spectral resolution. These methods cleanse pump-probe data and allow improved visualization and simpler analysis of the contained dynamics. We demonstrate these filters using visible pump/mid-infrared probe spectroscopy of ligand dissociation in carboxyhemoglobin.

Removing cross-phase modulation from midinfrared chirped-pulse upconversion spectra

We observe that narrow spectral features in mid-infrared spectra obtained by chirped-pulse up-conversion are strongly distorted by cross-phase modulation between the mid-infrared field and the chirped pulse. We discuss the consequences of this effect on spectral resolution, and introduce a correction method that recovers masked lines. This simple correction can be applied either when the upconverted field is fully characterized, such as in multidimensional spectroscopy, or when causality can be used, such as in absorption spectroscopy, which we demonstrate experimentally.