Drakolide Structure-activity Relationships for Sexual Attraction of Zeleboria Wasp Pollinator.

Orchids pollinated by sexual deception lure their specific male pollinators by sex pheromone mimicry. Despite the growing list of chemically diverse semiochemicals known to be involved, the chemical basis and flexibility of this extreme pollinator specificity are not fully understood. One promising but rarely applied tool is the synthesis and field testing of chemically related variants for investigating the structural specificity of the pheromone mimics. Here, we build on the discovery of the unusual semiochemical blend used by Drakaea micrantha to sexually lure its male Zeleboria thynnine wasp pollinator. This blend consists of a ß-ketolactone (drakolide) and two specific hydroxymethylpyrazines, presumably drawn from two distinct biosynthetic pathways. Here, we synthesized and tested the activity of various stereo- and structural isomers of the naturally occurring drakolide. Our study confirmed that in blends with the two pyrazines, both a mixture of stereoisomers, and the specific stereoisomer of the natural drakolide, elicit high rates of landings and attempted copulations. However, in the absence of pyrazines, both the number of responses and the level of sexual attraction were significantly reduced. When structural analogs were substituted for the natural drakolide, attractiveness and degree of sexual behaviour varied but were generally reduced. Based on our findings, and prior knowledge that related hydroxymethylpyrazines are active in other Drakaea spp., we conclude that the dual sex pheromone mimicry of D. micrantha likely evolved via initial changes in just one of the two biosynthetic pathways. Most plausibly, this involved modifications in the drakolides, with the pyrazines as a 'pre-adaption' enhancing the sexual response.

A Specific Blend of Drakolide and Hydroxymethylpyrazines: An Unusual Pollinator Sexual Attractant Used by the Endangered Orchid Drakaea micrantha.

Bioactive natural products underpin the intriguing pollination strategy used by sexually deceptive orchids. These compounds, which mimic the sex pheromones of the female insect, are emitted in particular blends to lure male insect pollinators of specific species. By combining methods from field biology, analytical chemistry, electrophysiology, crystallography, and organic synthesis, we report that an undescribed ß-hydroxylactone, in combination with two specific hydroxymethylpyrazines, act as pollinator attractants in the rare hammer orchid Drakaea micrantha. This discovery represents an unusual case of chemically unrelated compounds being used together as a sexual attractant. Furthermore, this is the first example of the identification of pollinator attractants in an endangered orchid, enabling the use of chemistry in orchid conservation. Our synthetic blend is now available to be used in pollinator surveys to locate suitable sites for plant conservation translocations.

Pen Torch Transillumination: Difficult Venepuncture Made Easy.

INTRODUCTION: Our novel technique of pen torch transillumination (PTI) uses a cheap and easily available instrument (Penlite-LP212®, Energizer®, Missouri, USA) to visualize superficial veins invisible to the naked eye. We evaluate the efficacy of PTI in improving venepuncture success rate (SR) for patients with poor venous access. METHODS: This prospective randomized controlled trial looked at adult patients (n = 69) aged 21-90 with difficult venous access (history of ≥3 consecutive attempts required for successful cannulation during the current admission) requiring non-emergent venepuncture. Patients underwent venepuncture over the upper-limb using one of the following: conventional venepuncture (control); Veinlite® EMS (TransLite®, Texas, USA), a commercial transillumination device; PTI. Outcome measures were: successful cannulation within 2 attempts and total duration of venepuncture. Fisher's exact and Kruskal-Wallis tests were performed. RESULTS: A significantly larger number of patients had successful venepuncture within 2 attempts using PTI (22/23, 95.7%) and Veinlite (23/23, 100%), compared to the controls (7/23, 30.4%) (p < 0.05). The total duration required for successful venepuncture was significantly shorter for Veinlite (mean 3.7 min, 1.0-5.3 min) and PTI (mean 8.5 min, range 1.08-27 min) compared to the controls (mean 23.2 min, range 1.88-46.5 min) (p < 0.05). CONCLUSIONS: PTI allows users to visualize veins invisible to the naked eye. Thrombosed/tortuous veins, branch points and valves, are easily identified and avoided. It has comparable efficacy to Veinlite® and is cheaper (Veinlite®-USD 227 vs. Penlite-LP212®-USD 7.00) and more easily available. PTI improves patient care, especially in developing regions where costs are a concern.

Types and distribution of congenital heart defects associated with trisomy 21 in Singapore.

AIM: Atrioventricular septal defect (AVSD) is widely accepted as the most common type of congenital heart defect in trisomy 21. Most of these studies, however, were conducted in Caucasian communities. The few Asian studies that had been conducted on this subject yielded different results. In the largest study of its kind in Asia, we described the distribution of types of congenital heart defects associated with trisomy 21 in Singapore. METHODS: Five hundred and eighty-eight patients with trisomy 21 born in 1996-2010, and confirmed by karyotyping, were included in the study. The diagnosis of congenital heart defects were made on echocardiography. Variables extracted for analysis were demographics (race and gender) and the types of congenital heart defects. Except for complex cyanotic heart defects, haemodynamically significant lesions were accounted for separately in cases where more than one type of congenital heart defect coexisted in a patient. RESULTS: Ventricular septal defect (VSD) (39.2%) was the most common congenital heart defect associated with trisomy 21 in our study, followed by patent ductus arteriosus (34.3%), secundum atrial septal defect (23.4%) and AVSD (15.6%). This study validates previous smaller Asian studies identifying VSD as the most common cardiac lesion associated with trisomy 21. A high proportion (25.0%) of trisomy 21 patients with tetralogy of Fallot also had AVSDs. Coarctation of the aorta was uncommon. CONCLUSION: VSD was the most common congenital heart defect seen in trisomy 21 in our study. A high proportion (25.0%) of trisomy 21 patients with tetralogy of Fallot also had AVSDs.

Smoking Characteristics and Readiness-to-Quit Status Among Smokers Attending Preoperative Assessment Clinic - A Prospective Cohort Study.

BACKGROUND: Perioperative smoking is associated with an increased incidence of general postoperative morbidity and mortality. The perioperative period is recognized as an important "teachable moment" that can motivate patients to adopt health changing behaviors. OBJECTIVE: In this study, we aimed to determine the prevalence of smokers among elective surgical patients in an Asian tertiary hospital. We also investigated their smoking characteristics, previous quitting attempts, readiness-to-quit status as well as knowledge of smoking-related postoperative complications. METHODS: We conducted a single-center prospective cohort study among all patients who attended a preoperative assessment clinic within a 2-month period (August to September 2020) using a preoperative smoking questionnaire. RESULTS: A total of 3362 patients participated in the study, of which 348 (10.4%) were current smokers. More than half (65.6%) of the smokers had previously attempted to quit smoking, with most (78%) having made more than one attempt. Forty-nine percent of current smokers were in the pre-contemplation stage of quitting and thirty-one percent were in the contemplation stage. Only twenty-one percent were in the preparation stage of quitting. Thirty-eight percent of patients recognized the importance of smoking cessation perioperatively but only twenty-eight percent were confident of quitting perioperatively. Less than sixty percent of smokers were aware of at least one type of smoking-related postoperative complication. Less than half of the patients (45%) had ever received advice on perioperative smoking cessation from the surgeons. CONCLUSION: A thorough understanding of smokers' smoking characteristics, barriers to quit and readiness-to-quit status are crucial to establishing a successful multidisciplinary perioperative smoking cessation program. Counselling should address knowledge deficits and be tailored to a patient's stage-of-change in order to seize this precious perioperative "teachable moment".

Tuberculosis care: enhancing directly observed therapy in a peri-urban, low socioeconomic status neighbourhood.

Tuberculosis (TB) is a major health issue in the Philippines. TB-Care was introduced in 2011 to tackle pulmonary TB among the urban poor in Payatas, Quezon City, Philippines. We evaluated the efficacy of TB-Care in increasing treatment success and compliance rates. This retrospective case series reviewed 44 patients with pulmonary TB enrolled in TB-Care from 2013 to 2014. Diagnosis and treatment of pulmonary TB was made in accordance with World Health Organization guidelines. Treatment outcomes included cure, completed treatment, successfully treated, failed treatment and transferred to another facility. 14 (73.7%) out of 19 patients tested were bacteriologically cured. The average 100% compliance rate was 90.8% over six months. The programme successfully treated 39 (88.6%) patients. This was comparable to the overall national treatment success rate of 90% for Philippines and 79% for Singapore, with higher compliance rates than were previously reported in this community.