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.

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.

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.

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.

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.

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.

Patterns of isosorbide dinitrate and glyceryl trinitrate metabolites formed by selected segments of the rabbit gastrointestinal tract.

Homogenates of selected segments of the rabbit gastrointestinal tract (GIT) were studied for their ability to biotransform isosorbide dinitrate (ISDN) and glyceryl trinitrate (GTN) to their mono- and di-nitrate metabolites, respectively. In addition, preferential formation of certain metabolites was investigated by examination of the patterns of metabolites formed by the various homogenates. After a 30-min incubation of ISDN with GIT homogenates (pH 7.4, 37 degrees C), the percent disappearance of ISDN and the ratio of isosorbide-2-mononitrate (2-ISMN) to isosorbide-5-mononitrate (5-ISMN) were as follows: stomach, 32%, 0.8; duodenum, 65%, 0.1; jejunum, 59%, 0.2; ileum, 38% , 1.2; cecum, 33%, 2.7; and colon, 32%, 3.4. After a 5-min incubation of GTN with GIT homogenates, the percent disappearance of GTN and the ratio of glyceryl-1,3-dinitrate (1,3-GDN) to glyceryl-1,2-dinitrate (1,2-GDN) were as follows: duodenum, 54%, 0.65; ileum, 73%, 0.68; and colon, 61%, 0.17. Incubation of 2 x 10(-7) M ISDN with mucosal and muscularis homogenates of duodenum, jejunum, and ileum resulted in significant losses of ISDN with an equimolar formation of the mononitrate metabolites. Most of the metabolic activity for ISDN resided in the mucosal layer of each section. The ratio of 2-ISMN to 5-ISMN varied in each section (stomach to colon) and cross section (mucosal versus muscularis) of the GIT. We conclude that the metabolism of ISDN and GTN by the GIT may contribute to the high clearance of these organic nitrates, and the low oral bioavailability of ISDN. Also, multiple mechanisms appear to be involved in the biotransformation of ISDN and GTN in the rabbit GIT.

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.

A comparative study of the inhibition of hepatic aldehyde dehydrogenases in the rat by methyltetrazolethiol, calcium carbimide, and disulfiram.

Methyltetrazolethiol (1-methyl-5-mercapto-1,2,3,4-tetrazole, MTT) is a heterocyclic substituent of the cephalosporin antibiotics, cefamandole, cefoperazone, and moxalactam. Pretreatment of rats with MTT has been reported to increase blood acetaldehyde concentration after ethanol administration. The time course of MTT-induced inhibition of hepatic aldehyde dehydrogenases (ALDH) was determined in adult, male Sprague-Dawley rats in comparison with the hepatic ALDH inhibition induced by calcium carbimide (calcium cyanamide, CC) and disulfiram (D). The apparent onset of maximal inhibition of hepatic low Km ALDH occurred at 2 h for 50 mg/kg MTT (subcutaneous, s.c.) and 7 mg/kg CC (oral) and at 24 h for 300 mg/kg D (oral). The relative magnitude of maximal inhibition of low Km ALDH was CC greater than D greater than MTT. The relative duration of enzyme inhibition was D greater than MTT greater than CC. High Km ALDH was only inhibited by CC. Hepatic low Km ALDH was selectively inhibited by s.c. and oral administration of 125 mg/kg MTT. For s.c. administration of 125 mg/kg MTT, the magnitude of maximal enzyme inhibition and the duration of inhibition were greater than for the 50 mg/kg dose. Oral administration of 125 mg/kg MTT produced similar inhibition of hepatic low Km ALDH compared with s.c. administration of the same dose. The time course of blood ethanol and acetaldehyde concentrations was determined for the intravenous infusion of two 0.3-g/kg doses of ethanol to rats that were pretreated orally with saline (1 h), MTT (125 mg/kg, 2 h), or CC (7 mg/kg, 1 h). The relative increase in blood acetaldehyde concentration compared with saline pretreatment was CC greater than MTT. The elimination of ethanol from blood was slower in the MTT- and CC-pretreated animals, and this effect was more pronounced for CC pretreatment. Overall, the data demonstrate that the characteristics of hepatic ALDH inhibition for MTT are different from those of the known ALDH inhibitors, CC and D.

Effect of 5-isosorbide mononitrate on isosorbide dinitrate-induced relaxation of rabbit aortic rings.

The ability of isosorbide dinitrate (ISDN) and its two metabolites, 5-isosorbide mononitrate (5-ISMN) and 2-isosorbide mononitrate (2-ISMN), to relax phenylephrine-contracted rabbit aortic rings was compared. The three organic nitrates demonstrated similar efficacy. ISDN was found to be the most potent (median effective dose (ED50); 1.5 X 10(-7) +/- 1.1 X 10(-7) M), followed by 2-ISMN (ED50, 1.8 X 10(-6) +/- 9 X 10(-7) M) and 5-ISMN (ED50, 8.2 X 10(-6) +/- 3.6 X 10(-6) M). The log dose-response curve of ISDN in rabbit aortic rings was constructed in the absence and presence of three fixed concentrations of 5-ISMN (5 X 10(-6), 10(-5), and 3 X 10(-5) M). No shift in the ISDN dose-response curve at high ISDN concentrations was noted in the presence of 5-ISMN. Using the isobolographic method with fixed ISDN/5-ISMN ratio mixtures, no evidence for an antagonistic effect of 5-ISMN on ISDN-induced vasodilation was obtained. Analysis of the fixed ISDN/5-ISMN ratio mixture responses by the median-effect plot showed no antagonistic effect. It is concluded that in rabbit aortic rings 5-ISMN, the major metabolite of ISDN, is not an antagonist of ISDN at a "nitrate receptor," and no support is provided for the hypothesis that the accumulation in plasma of metabolites (e.g., 5-ISMN) with longer half-lives than the parent drug explains tolerance to organic nitrates.