Impact of a novel pre-hospital stroke notification programme on acute stroke care key performance indicators in Hong Kong: a multicentre prospective cohort study with historical controls.

INTRODUCTION: Early identification and initiation of reperfusion therapy is essential for suspected acute ischaemic stroke. A pre-hospital stroke notification (PSN) protocol using FASE (facial drooping, arm weakness, speech difficulties, and eye palsy) was implemented to improve key performance indicators (KPIs) in acute stroke care delivery. We assessed KPIs and clinical outcomes before and after PSN implementation in Hong Kong. METHODS: This prospective cohort study with historical controls was conducted in the Accident and Emergency Departments of four public hospitals in Hong Kong. Patients were screened using the PSN protocol between August 2021 and February 2022. Suspected stroke patients between August 2020 and February 2021 were included as historical controls. Door-to-needle (DTN) and door-to-computed tomography (DTC) times before and after PSN implementation were compared. Clinical outcomes including National Institutes of Health Stroke Scale score at 24 hours and modified Rankin Scale score at 3 months after intravenous recombinant tissue-type plasminogen activator (IV-rtPA) were also assessed. RESULTS: Among the 715 patients (266 PSN and 449 non-PSN) included, 50.8% of PSN patients and 37.7% of non-PSN patients had a DTC time within 25 minutes (P<0.001). For the 58 PSN and 134 non-PSN patients given IV-rtPA, median DTN times were 67 and 75.5 minutes, respectively (P=0.007). The percentage of patients with a DTN time within 60 minutes was higher in the PSN group than in the non-PSN group (37.9% vs 21.6%; P=0.019). No statistically significant differences in clinical outcomes were observed. CONCLUSION: Although the PSN protocol shortened DTC and DTN times, clinical outcomes did not significantly differ.

Multilevel diffractive lens in the MWIR with extended depth-of-focus and wide field-of-view.

Optics in the mid-wave-infra-red (MWIR) band are generally heavy, thick and expensive. Here, we demonstrate multi-level diffractive lenses; one designed using inverse design and another using the conventional propagation phase (the Fresnel zone plate or FZP) with diameter = 25 mm and focal length = 25 mm operating at λ=4µm. We fabricated the lenses by optical lithography and compared their performance. We show that the inverse-designed MDL achieves larger depth-of-focus and better off-axis performance when compared to the FZP at the expense of larger spot size and reduced focusing efficiency. Both lenses are flat with thickness ≤0.5 mm and weigh ≤3.63 g, which are far smaller than their conventional refractive counterparts.

Binary orbits as the driver of γ-ray emission and mass ejection in classical novae.

Classical novae are the most common astrophysical thermonuclear explosions, occurring on the surfaces of white dwarf stars accreting gas from companions in binary star systems. Novae typically expel about 10(-4) solar masses of material at velocities exceeding 1,000 kilometres per second. However, the mechanism of mass ejection in novae is poorly understood, and could be dominated by the impulsive flash of thermonuclear energy, prolonged optically thick winds or binary interaction with the nova envelope. Classical novae are now routinely detected at gigaelectronvolt γ-ray wavelengths, suggesting that relativistic particles are accelerated by strong shocks in the ejecta. Here we report high-resolution radio imaging of the γ-ray-emitting nova V959 Mon. We find that its ejecta were shaped by the motion of the binary system: some gas was expelled rapidly along the poles as a wind from the white dwarf, while denser material drifted out along the equatorial plane, propelled by orbital motion. At the interface between the equatorial and polar regions, we observe synchrotron emission indicative of shocks and relativistic particle acceleration, thereby pinpointing the location of γ-ray production. Binary shaping of the nova ejecta and associated internal shocks are expected to be widespread among novae, explaining why many novae are γ-ray emitters.

Phospholamban cardiomyopathy: a Canadian perspective on a unique population.

INTRODUCTION: Phospholamban cardiomyopathy is an inherited cardiomyopathy, characterised by a defect in regulation of the sarcoplasmic reticulum Ca2+ pump, often presenting with malignant arrhythmias and progressive cardiac dysfunction occurring at a young age. METHODS: Phospholamban R14del mutation carriers and family members were identified from inherited arrhythmia clinics at 13 sites across Canada. Cardiac investigations, including electrocardiograms, Holter monitoring (premature ventricular complexes, PVCs), and imaging results were summarised. RESULTS: Fifty patients (10 families) were identified (median age 30 years, range 3-71, 46% female). Mutation carriers were more likely to be older, have low-voltage QRS, T­wave inversion, frequent PVCs, and cardiac dysfunction, compared to unaffected relatives. Increasing age, low-voltage QRS, T­wave inversion, late potentials, and frequent PVCs were predictors of cardiac dysfunction (p < 0.05 for all). Older carriers (age ≥45 years) were more likely to have disease manifestations than were their younger counterparts, with disease onset occurring at an older age in Canadian patients and their Dutch counterparts. DISCUSSION: Among Canadian patients with phospholamban cardiomyopathy, clinical manifestations resembled those of their Dutch counterparts, with increasing age a major predictor of disease manifestation. Older mutation carriers were more likely to have electrical and structural abnormalities, and may represent variable expressivity, age-dependent penetrance, or genetic heterogeneity among Canadian patients.

Reductions in all-cause and cause-specific mortality among HIV-infected individuals receiving antiretroviral therapy in British Columbia, Canada: 2001-2012.

OBJECTIVES: Since 2006, the British Columbia HIV/AIDS Drug Treatment Program (DTP) has expanded enrolment and dramatically increased its number of participants. We examined the effect this expansion has had on the underlying cause of death in HIV-infected individuals. METHODS: We analysed data from participants aged 18 years and older in the DTP to measure 2-year mortality rates and causes of death from 2001 to 2012. We conducted tests of trend for all-cause and cause-specific mortality, and compared demographics and characteristics of individuals. Cox proportional hazard models were used to determine the risk of death. RESULTS: A total of 8185 participants received antiretroviral therapy (ART) during the study period. Mortality declined from 3.88 per 100 person-years (PY) in 2001-2002 to 2.15 per 100 PY in 2011-2012 (P = 0.02). There were significant decreases in HIV-related deaths (2.34 to 0.56 per 100 PY; P = 0.02) and deaths attributable to chronic liver disease (0.20 to 0.09 per 100 PY; P = 0.01), cardiovascular disease (0.24 to 0.05 per 100 PY; P = 0.03) and suicides (0.47 to 0 per 100 PY; P = 0.003). Multivariate models, adjusted for age, gender, history of injecting drug use, AIDS diagnoses and baseline CD4 cell counts, demonstrated that initiation of ART in all time periods after 2001-2002 was independently associated with reduced mortality (P < 0.001). CONCLUSIONS: We observed declines in HIV-related mortality and certain non-HIV-related causes of death among participants in the BC DTP from 2001 to 2012. These findings suggest that there may be broader benefits to the increasingly liberal HIV treatment guidelines, including reductions in death caused by cardiovascular disease and chronic liver disease.

A limit on the variation of the speed of light arising from quantum gravity effects.

A cornerstone of Einstein's special relativity is Lorentz invariance-the postulate that all observers measure exactly the same speed of light in vacuum, independent of photon-energy. While special relativity assumes that there is no fundamental length-scale associated with such invariance, there is a fundamental scale (the Planck scale, l(Planck) approximately 1.62 x 10(-33) cm or E(Planck) = M(Planck)c(2) approximately 1.22 x 10(19) GeV), at which quantum effects are expected to strongly affect the nature of space-time. There is great interest in the (not yet validated) idea that Lorentz invariance might break near the Planck scale. A key test of such violation of Lorentz invariance is a possible variation of photon speed with energy. Even a tiny variation in photon speed, when accumulated over cosmological light-travel times, may be revealed by observing sharp features in gamma-ray burst (GRB) light-curves. Here we report the detection of emission up to approximately 31 GeV from the distant and short GRB 090510. We find no evidence for the violation of Lorentz invariance, and place a lower limit of 1.2E(Planck) on the scale of a linear energy dependence (or an inverse wavelength dependence), subject to reasonable assumptions about the emission (equivalently we have an upper limit of l(Planck)/1.2 on the length scale of the effect). Our results disfavour quantum-gravity theories in which the quantum nature of space-time on a very small scale linearly alters the speed of light.

Measurement of separate cosmic-ray electron and positron spectra with the fermi large area telescope.

We measured separate cosmic-ray electron and positron spectra with the Fermi Large Area Telescope. Because the instrument does not have an onboard magnet, we distinguish the two species by exploiting Earth's shadow, which is offset in opposite directions for opposite charges due to Earth's magnetic field. We estimate and subtract the cosmic-ray proton background using two different methods that produce consistent results. We report the electron-only spectrum, the positron-only spectrum, and the positron fraction between 20 and 200 GeV. We confirm that the fraction rises with energy in the 20-100 GeV range. The three new spectral points between 100 and 200 GeV are consistent with a fraction that is continuing to rise with energy.

Spectrum of the isotropic diffuse gamma-ray emission derived from first-year Fermi Large Area Telescope data.

We report on the first Fermi Large Area Telescope (LAT) measurements of the so-called "extragalactic" diffuse gamma-ray emission (EGB). This component of the diffuse gamma-ray emission is generally considered to have an isotropic or nearly isotropic distribution on the sky with diverse contributions discussed in the literature. The derivation of the EGB is based on detailed modeling of the bright foreground diffuse Galactic gamma-ray emission, the detected LAT sources, and the solar gamma-ray emission. We find the spectrum of the EGB is consistent with a power law with a differential spectral index gamma = 2.41 +/- 0.05 and intensity I(>100 MeV) = (1.03 +/- 0.17) x 10(-5) cm(-2) s(-1) sr(-1), where the error is systematics dominated. Our EGB spectrum is featureless, less intense, and softer than that derived from EGRET data.

Fermi large area telescope measurements of the diffuse gamma-ray emission at intermediate galactic latitudes.

The diffuse galactic gamma-ray emission is produced by cosmic rays (CRs) interacting with the interstellar gas and radiation field. Measurements by the Energetic Gamma-Ray Experiment Telescope (EGRET) instrument on the Compton Gamma-Ray Observatory indicated excess gamma-ray emission greater, > or approximately equal to 1 GeV relative to diffuse galactic gamma-ray emission models consistent with directly measured CR spectra (the so-called "EGRET GeV excess"). The Large Area Telescope (LAT) instrument on the Fermi Gamma-Ray Space Telescope has measured the diffuse gamma-ray emission with improved sensitivity and resolution compared to EGRET. We report on LAT measurements for energies 100 MeV to 10 GeV and galactic latitudes 10 degrees < or = |b| < or = 20 degrees. The LAT spectrum for this region of the sky is well reproduced by a diffuse galactic gamma-ray emission model that is consistent with local CR spectra and inconsistent with the EGRET GeV excess.

Experience sharing on the implementation of telehealth system in Hong Kong.

With the growth of the ageing population in Hong Kong, healthcare professionals believe that there will be a great demand of healthcare service at the community level. In 2000, the first prototype of telehealth system was developed, tested and validated by the School of Nursing, The Hong Kong Polytechnic University. With the advancement of information technology and inexpensive video- conference facility, an inter-clinic patient-centered healthcare information system has been evolved and used by a number of satellite clinics since 2003. In order to foster the importance of personal healthcare education at the community level, different versions of the telehealth system were designed and developed for school children and teenagers. Now the research team is focusing on the development of the pocket PC's version. Experience on the deployment of such technology-intensive system in healthcare was discussed in this paper.

Galanin: an unassuming neuropeptide moves to center stage in reproduction.

Galanin is a neuropeptide widely distributed throughout the reproductive system, including the brain, pituitary, testes, ovaries, and accessory reproductive tracts of both sexes. Within the hypothalamus, a subset of GnRH-producing neurons also synthesizes galanin. Galanin gene expression in these GnRH neurons is highly inducible by estrogen. Galanin is thought to play an important role in the generation of the preovulatory LH surge, and may serve other functions yet to be discovered.

Proopiomelanocortin neurons are direct targets for leptin in the hypothalamus.

Leptin is a protein product of the obese (ob) gene, which is secreted by adipocytes and functions as a satiety factor to regulate food intake. The expression of the leptin receptor in several hypothalamic nuclei suggests that multiple neuronal subtypes are targets for leptin's action. Products of the proopiomelanocortin (POMC) gene are known to affect feeding behavior, and POMC neurons share a similar distribution with leptin receptor mRNA in the arcuate nucleus. We used double label in situ hybridization and computerized image analysis to test the hypothesis that POMC neurons coexpress the leptin receptor. Quantitative analysis confirmed that POMC neurons in the hypothalamus express leptin receptor mRNA. Based on this observation, we infer that POMC neurons and the products of the POMC gene may be part of the signaling pathway mediating leptin's action on feeding and perhaps other physiological functions.

Regulation of hypothalamic proopiomelanocortin mRNA by leptin in ob/ob mice.

The hormone leptin acts on the brain to regulate feeding, metabolism, and reproduction; however, its cellular targets and molecular mechanisms of action remain to be fully elucidated. The melanocortins, which are derived from the precursor proopiomelanocortin (POMC), are also implicated in the physiological regulation of body weight. POMC-containing neurons express the leptin receptor, and thus it is conceivable that the POMC gene itself may be part of the signaling pathway involved in leptin's action on the brain. Using in situ hybridization and computerized image analysis, we tested the hypothesis that the POMC gene is a target for regulation by leptin by comparing cellular levels of POMC mRNA in the hypothalamus among groups of leptin-deficient (ob/ob) mice, leptin-treated ob/ob mice, and wild-type controls. POMC mRNA levels were significantly reduced throughout the arcuate nucleus in vehicle-treated ob/ob mice relative to wild-type controls, whereas POMC mRNA levels in leptin-treated ob/ob mice were indistinguishable from wild-type controls. These observations suggest that one or more products of POMC serve as an integrative link between leptin and the central mechanisms governing body weight regulation and reproduction.

Leptin is a metabolic signal to the reproductive system.

Leptin, a newly-discovered hormonal product of the obese (ob) gene, is expressed by adipocytes and thought to play a role in the regulation of food intake and metabolism. We tested the hypothesis that leptin signals metabolic information to the reproductive system by examining its effects on the reproductive system of ob/ob mice, which have a congenital deficiency in leptin and are infertile. We treated pair-fed males and females with leptin (50 microg twice daily, ip) or vehicle (n=10/group) for 14 days, after which the animals were bled and killed. Leptin-treated females had significantly elevated serum levels of LH, increased ovarian and uterine weights, and stimulated aspects of ovarian and uterine histology compared to controls. Leptin-treated males had significantly elevated serum levels of FSH, increased testicular and seminal vesicle weights, greater seminal vesicle epithelial cell height, and elevated sperm counts compared to controls. These results demonstrate that leptin stimulates the reproductive endocrine system in both sexes of ob/ob mice and suggest that leptin may serve as a permissive signal to the reproductive system of normal animals.

Leptin is a metabolic gate for the onset of puberty in the female rat.

The timing of puberty onset in mammals is tightly coupled to the animal's nutritional and metabolic state. We conducted two experiments to test the hypothesis that leptin acts as a metabolic signal for the onset of puberty. In the first experiment, we administered leptin (6.3 micrograms/g twice daily) to a group of normal prepubertal female rats and compared their rate of sexual maturation to that of two control groups. The group of leptin-treated animals and one group of control animals were allowed to eat ad lib, while the other group of control animals was pair-fed to the leptin-treated group. Food intake in the leptin-treated group was reduced to approximately 80% of the ad lib-fed control group, resulting in retarded growth in both leptin-treated and pair-fed animals. All measured indices of pubertal maturation-age at vaginal opening, age at first estrus, ovarian weight, ovulatory index (corpora lutea/ovarian section), uterine weight, and uterine cross-sectional area-were significantly delayed in the pair-fed group but not different between the leptin-treated group and ad lib-fed controls. The second experiment was similar to the first, except that both the leptin-treated group and the pair-fed group were fed at 70% of the ad lib-fed controls. Under these conditions, leptin only partially reversed the delay in sexual maturation, as reflected by the age at vaginal opening and first estrus. These results suggest that leptin is not the primary signal that initiates the onset of puberty but that instead, it acts in a permissive fashion, as a metabolic gate, to allow pubertal maturation to proceed-if and when metabolic resources are deemed adequate; moreover, these observations suggest that other metabolic factors, besides leptin, influence the timing of puberty onset under conditions of more severe dietary stress.

The spectrum and significance of primary hypophysitis.

Hypophysitis can present clinically as a mass lesion of the sella turcica. Secondary hypophysitis occurs in cases where a definite etiologic agent or process inciting the inflammatory reaction can be identified. In contrast, primary hypophysitis refers to inflammation confined to the pituitary gland with no identifiable etiologic associations. We report three cases of primary hypophysitis to illustrate the spectrum of three clinicopathological entities that encompass this disease: lymphocytic hypophysitis, granulomatous hypophysitis, and xanthomatous hypophysitis. Our three patients underwent surgery, with variable response. However, conservative, supportive treatment with or without surgical decompression is generally favored over aggressive and extensive surgical resection that results in hypopituitarism. We conclude that the optimal management of patients with hyophysitis requires a high index of suspicion before extensive surgical resection. Histological confirmation of the diagnosis of hypophysitis can be obtained by performing a biopsy or by requesting an intraoperative frozen section consultation.

Molecular basis off hurthle cell papillary thyroid carcinoma.

Among thyroid neoplasms, Hurthle cell tumors (HCTs) have traditionally been a distinct diagnostic category. Hurthle cell adenomas are encapsulated follicular lesions with benign behavior. Hurthle cell carcinomas exhibit unequivocal capsular and/or vascular invasion; they are aggressive tumors with a poor prognosis. Recently, Hurthle cell papillary thyroid carcinomas (PTCs) have been identified on morphological grounds. We hypothesize that a subset of HCTs represent PTC with clinical, histological, and immunohistochemical features based on specific molecular events. ret/PTC gene rearrangements give rise to novel oncogenes that are unique to PTC. We studied a group (n = 50) of HCTs for ret/PTC gene rearrangements. Tumors were examined for papillary differentiation by light microscopic evaluation of nuclear features, by RT-PCR for ret/PTC gene rearrangements, and by immunohistochemistry for ret. Among 24 noninvasive tumors, 13 contained ribonucleic acid for ret/PTC-1, -2, or -3, and 9 of these were immunoreactive for ret. Among 19 Hurthle cell carcinomas, 15 had focal nuclear hypochromasia with grooves and/or inclusions; expressed transcripts of ret/PTC-1, -2, or-3; and exhibited ret positivity. Tumors with ret/PTC gene rearrangements tended to have lymph node metastases rather than hematogenous spread. Our results indicate that a subset of HCTs exhibit features of PTC that are attributable to specific gene rearrangements, resulting in expression of ret/PTC oncogenes. These data support subclassification of HCTs into three groups: Hurthle cell adenomas, Hurthle cell carcinomas, and Hurthle cell PTC.

Analysis of ret/PTC gene rearrangements refines the fine needle aspiration diagnosis of thyroid cancer.

Papillary carcinoma (PC) represents the most common malignancy of the thyroid gland. Therefore, the assessment of fine needle aspiration biopsies of thyroid nodules rests heavily on the identification of nuclear features of PC. The ret/PTC oncogene, formed by several gene rearrangements, is specific for PC among thyroid tumors. In this study we examined thyroid aspirates for the presence of ret/PTC gene rearrangements by RT-PCR and Southern hybridization. We prospectively collected thyroid aspirates in Cytolyt solution and prepared slides for cytological examination using the ThinPrep method. All remaining material was then used for nucleic acid extraction with subsequent RT-PCR for the housekeeping gene PGK-1 to ensure ribonucleic acid integrity, for thyroglobulin to ensure the presence of follicular epithelial cells, and for the three most common ret/PTC gene rearrangements (ret/PTC-1, -2, and -3). The results of the first 73 cases with surgical follow-up were correlated with the cytological diagnosis and final histopathology. ret/PTC gene rearrangements were detected in 17 of 33 samples (52%) that were PC on histopathology; the presence of gene rearrangements was confirmed by molecular analysis of corresponding surgically resected frozen tissue. There were no false positives. The identification of ret/PTC gene rearrangements refined the diagnosis of PC in 9 of 15 specimens (60%) that would otherwise have been considered indeterminate and in 2 of 6 that were considered insufficient for cytological diagnosis. The results indicate that RT-PCR for ret/PTC is a specific marker that can be applied to fine needle aspiration biopsies and improves the diagnosis of malignancy when used as an adjunct to traditional cytology.

Primary structure of a cardioactive neuropeptide from the tobacco hawkmoth, Manduca sexta.

The amino acid sequence of the first of a family of insect cardioregulatory peptides from the tobacco hawkmoth, Manduca sexta, has been determined using a combination of Edman degradation microsequencing and mass spectroscopy. This peptide contains 9 amino acid residues and an observed mass for the monoisotopic protonated molecule of 956.4 Da. There are two cysteines at positions 3 and 9 forming a disulfide bridge and the carboxyl-terminus is amidated. The structure of this peptide, Pro-Phe-Cys-Asn-Ala-Phe-Thr-Gly-Cys-NH2, is identical to a peptide recently isolated from crabs called crustacean cardioactive peptide (CCAP) and we propose that this peptide be named Manduca CCAP.

Amino acid sequence of CAP2b, an insect cardioacceleratory peptide from the tobacco hawkmoth Manduca sexta.

The primary structure of a novel insect neuropeptide, Cardioacceleratory Peptide 2b (CAP2b), from the tobacco hawkmoth Manduca sexta has been established using a combination of mass spectroscopy, Edman degradation microsequencing, amino acid analysis, and biological assays. The sequence of CAP2b, pyroGlu-Leu-Tyr-Ala-Phe-Pro-Arg-Val-amide, has a molecular weight of 974.6 and is blocked at both the amino and carboxyl ends. Examination of several national computer protein data bases failed to reveal other peptides or proteins with any sequence homology to CAP2b indicating that this is likely to be a novel insect neuropeptide. This peptide may be a general activator of insect viscera since it causes an increase in heart rate in Manduca and in Drosophila, and has also been implicated in the regulation of fluid secretion by the Malphigian tubules of Drosophila.