Serial surveys of Hong Kong medical students regarding attitudes towards HIV/AIDS from 2007 to 2017.

INTRODUCTION: With widespread adoption of antiretroviral therapy, human immunodeficiency virus (HIV) epidemiology has changed since the late 2000s. Accordingly, attitudes towards the disease may also have changed. Because medical students are future physicians, their attitudes have important implications in access to care among patients with HIV/acquired immunodeficiency syndrome (AIDS). Here, we performed a survey to compare medical students' attitudes towards HIV/AIDS between the late 2000s (2007-2010) and middle 2010s (2014- 2017). METHODS: From 2007 to 2010, we surveyed three cohorts of medical students at the end of clinical training to assess their attitudes towards HIV/AIDS. From 2014 to 2017, we surveyed three additional cohorts of medical students at the end of clinical training to compare changes in attitudes towards HIV/AIDS between the late 2000s and middle 2010s. Each set of three cohorts was grouped together to maximise sample size; comparisons were performed between the 2007-2010 and 2014-2017 cohorts. RESULTS: From 2007 to 2010, 546 medical students were surveyed; from 2014 to 2017, 504 students were surveyed. Compared with students in the late 2000s, significantly fewer students in the mid-2010s initially encountered patients with HIV during attachment to an HIV clinic or preferred to avoid work in a field involving HIV/AIDS; significantly more students planned to specialise in HIV medicine. Student willingness to provide HIV care remained similar over time: approximately 78% of students were willing to provide care in each grouped cohort. CONCLUSION: Although medical students had more positive attitudes towards HIV/AIDS, their willingness to provide HIV care did not change between the late 2000s and middle 2010s.

Mixed methods study on elimination of tuberculosis in Hong Kong.

INTRODUCTION: Tuberculosis (TB) commonly affects developing countries. Several developed regions in Asian still have a stagnant intermediate TB burden. Information to adequately inform TB strategies is lacking. We conducted a mixed methods study to fill this information gap in Hong Kong. METHODS: Data from the Hong Kong government were used to analyse trends of TB notification rates compared with World Health Organization (WHO) targets. A review of policy documents and literature was conducted to evaluate TB control and elimination in Hong Kong. RESULTS: Extrapolated trends showed that Hong Kong will be unable to meet the WHO target of a 90% drop in incidence rate by 2030. The policy review showed that the Hong Kong government has not set a clear strategy and timeline for specific goals in TB control and elimination. The literature review found that older adults are largely responsible for the stagnant TB prevalence because of reactivation of latent TB infection (LTBI), while mortality of hospitalised patients with TB is still high because of delayed diagnosis and treatment. CONCLUSION: Tuberculosis incidence is currently under control in Hong Kong, but further actions are needed if the elimination targets are to be achieved. Improved diagnostic tools are required, and policies targeting LTBI in older adults should be implemented to achieve the WHO target by 2030.

Interpreting the transmissibility of the avian influenza A(H7N9) infection from 2013 to 2015 in Zhejiang Province, China.

Three epidemic waves of human influenza A(H7N9) were documented in several different provinces in China between 2013 and 2015. With limited understanding of the potential for human-to-human transmission, it was difficult to implement control measures efficiently or to inform the public adequately about the application of interventions. In this study, the human-to-human transmission rate for the epidemics that occurred between 2013 and 2015 in Zhejiang Province, China, was analysed. The reproduction number (R), a key indicator of transmission intensity, was estimated by fitting the number of infections from poultry to humans and from humans to humans into a mathematical model. The posterior mean R for human-to-human transmission was estimated to be 0·27, with a 95% credible interval of 0·14-0·44 for the first wave, whereas the posterior mean Rs decreased to 0·15 in the second and third waves. Overall, these estimates indicate that a human H7N9 pandemic is unlikely to occur in Zhejiang. The reductions in the viral transmissibility and the number of poultry-transmitted infections after the first epidemic may be attributable to the various intervention measures taken, including changes in the extent of closures of live poultry markets.

Spontaneous circumferential intramural esophageal dissection complicated with esophageal perforation and esophageal-pleural fistula: a case report and literature review.

Spontaneous intramural esophageal dissection (IED) is a rare disease entity. There are few reports of spontaneous IED requiring surgical treatment. Hereby, we report a 37-year-old gentleman who was diagnosed to have spontaneous extensive circumferential IED complicated with esophageal perforation, empyema, and esophageal-pleural fistula. Esophageal stenting and drainage of empyema were unsuccessful. Computed tomography and gastrografin contrast swallow demonstrated a leak to the pleural cavity, suggestive of esophageal-pleural fistula. Subsequently, a two-stage operation was performed: cervical esophagogastrostomy to bypass the perforated esophagus, followed by esophagectomy and decortication of the right lung. The patient recovered and was discharged home after a 3-week hospitalization. The management principles and recent published literature related to IED were reviewed.

Recanalization of Left Subclavian Vein Total Occlusion Jailed by Superior Vena Cava Stent Using Culotte Stenting Technique With a Dedicated Venous Stent.

This case demonstrates that the high radial strength of a dedicated nitinol venous stent is able to achieve good acute angiographic results and clinical efficacy.

Evaluation of computerized analysis of sperm movement characteristics and differential sperm tail swelling patterns in predicting human sperm in vitro fertilizing capacity.

Multivariate discriminant analysis was used to evaluate the usefulness of computer image analysis of sperm movement characteristics and differential patterns of sperm tail swelling after hypoosmotic treatment for predicting the human sperm in vitro fertilizing capacity assessed by the zona-free hamster egg penetration assay. Fifty-five semen samples, mostly normospermic, from untreated infertility clinic patients were analyzed. The % normal sperm morphology, linearity of seminal sperm movement, seminal sperm head beat frequency, mean and maximum amplitudes of lateral head displacement, and hypoosmotic sperm tail swelling patterns c, d and f were selected by multivariate discriminant analysis to be capable of discriminating the samples exhibiting the presence or the absence of sperm in vitro fertilizing capacity. The % total sperm tail swelling did not give additional information about in vitro fertilizing capacity. These preliminary data suggest that computer image analysis of sperm movement characteristics and differential evaluation of hypoosmotic sperm tail swelling might be useful for the prediction of human sperm fertility. Further prospective studies are necessary to validate their predictive functions.

Whole-body retention, excretion and metabolism of [74As]arsenic acid in the hamster.

In order to assess the whole-body retention, excretion and metabolism of inorganic arsenic, male and female hamsters were given either a single oral or i.v. dose of 74As (congruent to 33' microCi/hamster; 0.01 micrograms arsenic/hamster) as arsenic acid. 74As radioactivity was measured in the whole body, urine and feces for up to 35 days. 24-h samples of urine were analyzed for arsenic metabolites. For the i.v. dosed hamsters, the half-period of elimination for the first component (65% of the dose) was 0.40 days; the second component (35% of the dose) had a half-period of 4.5 days. For the orally dosed hamsters, the half-period of elimination for the first component (98% of the dose) was 0.29 days; the second component (2% of the dose) had a half-period of 3.8 days. Differences in the percent of dose excreted between oral and i.v. dosed hamsters appeared to be due to the increased fecal excretion of arsenic (70%) in the orally dosed hamsters as compared to the i.v.v dosed hamsters (6%). No statistically significant differences between the i.v. and oral treatments were found in the half-periods of elimination for either of the 2 components. Analysis of the urine for metabolites revealed arsenic was present as dimethylarsinic acid and inorganic arsenic.

The prevalence of low vision and blindness in Canada.

PURPOSE: The purpose of this study was to ascertain the prevalence and primary causes of visual impairment in a representative Canadian population. METHODS: We reviewed a representative sample of patients who attended ophthalmologists' offices in a medium-sized Canadian city between 1996 and 2001 in order to estimate the prevalence of visual impairment. Demographic data, visual diagnoses, best-corrected visual acuities (BCVA), and visual field information were recorded. Visual status was categorized based on accepted World Health Organization (WHO) and North American criteria. Population data were obtained from the Canadian census. RESULTS: The prevalence of low vision and blindness in our population was 35.6 and 3.8 per 10 000 individuals, according to the WHO classification, and 71.2 and 23.6 per 10 000 individuals, using the North American definition. Among individuals with some vision loss (vision worse than 20/40), cataract and visual pathway disease were the most common causes, together accounting for 40% of visual impairment. Age-related macular degeneration and other retinal diseases were the next most common causes of vision loss. Diabetic retinopathy and glaucoma were less frequently encountered as causes of visual impairment. CONCLUSION: The overall prevalence of low vision and blindness in Canada are in keeping with data from large population-based studies from other developed nations. Cataract, visual pathway disease, and macular degeneration are the leading causes of visual impairment. These results are important for enhancing our understanding of the scope of vision health in Canada and may direct future health planning and cost-utilization research.

Low power laser therapy and analgesic action.

OBJECTIVE: The semiconductor or laser diode (GaAs, 904 nm) is the most appropriate choice in pain reduction therapy. SUMMARY BACKGROUND DATA: Low-power density laser acts on the prostaglandin (PG) synthesis, increasing the change of PGG2 and PGH2 into PG12 (also called prostacyclin, or epoprostenol). The last is the main product of the arachidonic acid into the endothelial cells and into the smooth muscular cells of vessel walls, that have a vasodilating and anti-inflammatory action. METHODS: Treatment was performed on 372 patients (206 women and 166 men) during the period between May 1987 and January 1997. The patients, whose ages ranged from 25 to 70 years, with a mean age of 45 years, suffered from rheumatic, degenerative, and traumatic pathologies as well as cutaneous ulcers. The majority of patients had been seen by orthopedists and rheumatologists and had undergone x-ray examination. All patients had received drug-based treatment and/or physiotherapy with poor results; 5 patients had also been irradiated with He:Ne and CO2 lasers. Two-thirds were experiencing acute symptomatic pain, while the others suffered long-term pathology with recurrent crises. We used a pulsed diode laser, GaAs 904 nm wavelength once per day for 5 consecutive days, followed by a 2-day interval. The average number of applications was 12. We irradiated the trigger points, access points to the joint, and striated muscles adjacent to relevant nerve roots. RESULTS: We achieved very good results, especially in cases of symptomatic osteoarthritis of the cervical vertebrae, sport-related injuries, epicondylitis, and cutaneous ulcers, and with cases of osteoarthritis of the coxa. CONCLUSIONS: Treatment with 904-nm diode laser has substantially reduced the symptoms as well as improved the quality of life of these patient, ultimately postponing the need for surgery.

Determination of arsenic in urine and feces by dry ashing, atomic absorption spectrometry.

A dry ashing flameless atomic absorption procedure was used to determine fish-arsenic in human urine and feces. Samples were dry ashed with Mg(NO3)2--MgO and dissolved in 6N HCl. Arsine was generated by the addition of NaBH4 and swept into a thermally heated silica tube furnace. Recoveries of several arsenic compounds added to samples ranged from 85 to 117%. The detection limit was about 3 ppb as for 10 g sample. Effects of the presence of common cations, anions and acids were studied.

Recovery studies of selenium using dry ashing procedure with ashing aid.

A previously reported dry ashing procedure for the decomposition of marine samples prior to arsenic determination is demonstrated to be equally applicable to the analysis of selenium. Quantitative recovery of selenium as inorganic or organic compounds in a variety of plants and animal tissues is demonstrated using 75Se tracer and X-ray fluorescence techniques. The dry ashing procedure is simpler than the official AOAC method, which uses a mixture of H2SO4, HNO3 and HC10(4).

Dry ashing, hydride generation atomic absorption spectrometric determination of arsenic and selenium in foods.

A dry ashing, flameless atomic absorption spectrometric method was evaluated to determine arsenic and selenium in foods. Samples were dry-ashed with Mg(NO3)2-MgO and dissolved in HCl. Selenate was reduced to selenite by boiling in 4N HCl. Selenate was reduced to selenite by boiling in 4N HCl, and arsenate to arsenite by treatment with KI. Hydrides of arsenic and selenium were generated by the addition of NaBH4 and were swept by nitrogen and hydrogen into a thermally heated silicate tube furnace. The detection limit was about 5 ppb for each element based on a 10 g sample. Analytical results obtained for several samples of NBS reference materials agreed with the certified values. The procedure was evaluated by another laboratory and results were satisfactory.

Isolation of Arabidopsis thaliana mutants hypersensitive to gamma radiation.

A screening method for mutants of Arabidopsis thaliana hypersensitive to gamma-radiation has been devised. Plants grown from ethyl methanesulfonate (EMS)-treated seeds were irradiated at the seedling stage, which is highly radiosensitive due to extensive cell division. Severe growth inhibition of mutant plants by a gamma-ray dose which only slightly affects wild-type plants was the selective criterion. Twelve true-breeding hypersensitive lines were isolated from a total of 3394 screened plants. Genetic analysis of five of the lines revealed five new genes, designated RAD1-RAD5. These Arabidopsis RAD mutants are phenotypically similar to mutants in the RAD52 epistasis group of Saccharomyces cerevisiae, which are highly sensitive to ionizing radiation but not hypersensitive to UV light. One possibility is that the Arabidopsis mutants are defective in a nonhomologous or illegitimate recombination mechanism used by plants for repair of chromosome breaks.

Leaky transcription termination produces larger and smaller than genome size hepatitis B virus X gene transcripts.

The genomic DNA of hepatitis B virus (HBV) is circular and has only one known transcription termination site. The HBV X protein coding sequence is flanked by this transcription termination site at the 3' end and a promoter element at the 5' end. Transcription initiating from the X promoter and terminating at the termination site would produce a transcript 0.7 kb in length, which we have detected in cell lines that produce HBV particles. Unexpectedly, a 3.9-kb transcript containing two copies of the X gene sequence was also detected in these cell lines. Polymerase chain reaction analysis indicates that this 3.9-kb transcript contains sequences from both upstream and downstream of the termination site. Thus, transcription of this 3.9-kb transcript initiates from the X promoter, reads through the termination site, and terminates the second time it encounters the site. Analysis using an SV40-derived vector indicates that the transcription termination site in the HBV genome is also leaky for X gene transcription when a heterologous promoter initiates the transcription. Based on these results, the mechanism of how the transcription termination of HBV mRNA is regulated is discussed.

Sex- and species-related differences in the biotransformation of isosorbide dinitrate by various tissues of the rabbit and rat.

The biotransformation of isosorbide dinitrate (ISDN) by various tissues of the rabbit and rat was examined. Incubation of 2 X 10(-7) M ISDN at 37 degrees C with tissue homogenates of liver, lung, kidney, intestine, skeletal muscle, aorta, and erythrocytes from the rabbit and rat resulted in a significant disappearance of ISDN after a 30-min incubation (also, 5-min incubation for liver). The disappearance of ISDN in each tissue homogenate was accompanied by an equimolar production of the mononitrate metabolites, isosorbide-2-mononitrate (2-ISMN) and isosorbide-5-mononitrate (5-ISMN), with the exception of liver homogenates where the loss of ISDN could not be accounted for by mononitrate formation. The relative rate of ISDN disappearance in various tissue homogenates was for the male rabbit, liver greater than lung approximately intestine greater than kidney greater than erythrocytes approximately skeletal muscle approximately aorta; for the female rabbit, liver greater than kidney approximately lung approximately intestine greater than erythrocytes approximately skeletal muscle approximately aorta; and for the male rat, liver greater than intestine greater than erythrocytes greater than skeletal muscle greater than lung approximately kidney. A sex difference in the percent disappearance of ISDN was observed in homogenates of lung and intestine from male and female rabbits. In addition, a sex difference in the ratio of metabolite (2-ISMN/5-ISMN) formed by denitration of ISDN was seen in homogenates of lung, skeletal muscle, and erythrocyte lysate.(ABSTRACT TRUNCATED AT 250 WORDS)

Determination of isosorbide dinitrate biotransformation in various tissues of the rabbit by capillary column gas-liquid chromatography.

A selective and sensitive capillary column gas-liquid chromatographic procedure has been developed for the simultaneous determination of isosorbide dinitrate (ISDN) and its mononitrate metabolites in rabbit blood and tissue homogenates. The method has a limit of detection of 0.1 ng ml-1 for ISDN, 1 ng ml-1 for isosorbide 5-mononitrate (5-ISMN), and 2 ng ml-1 for isosorbide 2-mononitrate (2-ISMN). The day-to-day coefficients of variation were 2.5, 6.8, and 11.3 per cent for ISDN, 5-ISMN, and 2-ISMN, respectively. The within-day coefficients of variation were 2.7, 4.9 and 6.5 per cent for ISDN, 5-ISMN, and 2-ISMN, respectively. The procedure was used to determine the biotransformation of ISDN (2 X 10(-7) M) to 5-ISMN and 2-ISMN by various rabbit tissue homogenates. The relative rate of biotransformation of ISDN was liver greater than lung approximately equal to intestine greater than kidney greater than blood approximately equal to skeletal muscle, with the lung and intestine homogenates being about two-thirds as active as liver homogenates. These results indicate that extrahepatic biotransformation of ISDN, especially by lung and intestine, may contribute to the systemic clearance of ISDN in the rabbit.