Morphology and Spectral Absorption Characteristics of Retinal Photoreceptors in the Southern Hemisphere Lamprey (Geotria australis)

The morphology and spectral absorption characteristics of the retinal photoreceptors in the southern hemisphere lamprey Geotria australis (Agnatha) were studied using light and electron microscopy and microspectrophotometry. The retinae of both downstream and upstream migrants of Geotria contained two types of cone photoreceptor and one type of rod photoreceptor. Visual pigments contained in the outer segments of these three photoreceptor types had absorbance spectra typical of porphyropsins and with wavelengths of maximum absorbance (downstream/upstream) at 610/616 nm (long-wavelength-sensitive cone,LWS),515/515nm(medium-wavelength-sensitive cone, MWS), and 506/500 nm (medium-wavelength-sensitive rod). A "yellow" photostable pigment was present in the myoid region of all three types of photoreceptor in the downstream migrant. The same short-wavelength-absorbing pigment, which prevents photostimulation of the beta band of the visual pigment in the outer segment, was present in the rods and LWS cones of the upstream migrant, but was replaced by a large transparent ellipsosome in the MWS cones. Using microspectrophotometric and anatomical data, the quantal spectral sensitivity of each photoreceptor type was calculated. Our results provide the first evidence of a jawless vertebrate, represented today solely by the lampreys and hagfishes, with two morphologically and physiologically distinct types of cone photoreceptors, in addition to a rod-like photoreceptor containing a colored filter (a cone-like characteristic). In contrast, all other lampreys studied thus far have either (1) one type of cone and one type of rod, or (2) a single type of rod-like photoreceptor. The evolution or retention of a second type of cone in adult Geotria is presumably an adaptation to life in the brightly lit surface waters of the Southern Ocean, where this species lives during the marine phase of its life cycle. The functional significance of the unique visual system of Geotria is discussed in relation to its life cycle and the potential for color vision

Vision in the Southern Hemisphere Lamprey Mordacia Mordax: Spatial Distribution, Spectral Absorption Characteristics, and Optical Sensitivity of a Single Class of Retinal Photoreceptor

The dorso-laterally located eyes of the southern hemisphere lamprey Mordacia mordax (Agnatha) contain a single morphological type of retinal photoreceptor, which possesses ultrastructural characteristics of both rods and cones. This photoreceptor has a large refractile ellipsosome in the inner segment and a long cylindrical outer segment surrounded by a retinal pigment epithelium that contains two types of tapetal reflectors. The photoreceptors form a hexagonal array and attain their peak density (33,200 receptors0mm2) in the ventro-temporal retina. Using the size and spacing of the photoreceptors and direct measures of aperture size and eye dimensions, the peak spatial resolving power and optical sensitivity are estimated to be 1.7 cycles deg21 (minimum separable angle of 34'7'' ) and 0.64 mm2 steradian (white light) and 1.38 mm2 steradian (preferred wavelength or lmax), respectively. Microspectrophotometry reveals that the visual pigment located within the outer segment is a rhodopsin with a wavelength of maximum absorbance (lmax) at 514 nm. The ellipsosome has very low absorptance (,0.05) across the measured spectrum (350-750 nm) and probably does not act as a spectral filter. In contrast to all other lampreys studied, the optimized receptor packing, the large width of the ellipsosome-bearing inner segment, together with the presence of a retinal tapetum in the photophobic Mordacia, all represent adaptations for low light vision and optimizing photon capture

Risk of peanut- and tree-nut-induced anaphylaxis during Halloween, Easter and other cultural holidays in Canadian children.

BACKGROUND: It is not established whether the risk of anaphylaxis induced by peanuts or tree nuts in children increases at specific times of the year. We aimed to evaluate the risk of peanut-and tree-nut-induced anaphylaxis during certain cultural holidays in Canadian children. METHODS: We collected data on confirmed pediatric cases of anaphylaxis presenting to emergency departments in 4 Canadian provinces as part of the Cross-Canada Anaphylaxis Registry. We assessed the mean number of cases per day and incidence rate ratio (IRR) of anaphylaxis induced by unknown nuts, peanuts and tree nuts presenting during each of 6 holidays (Halloween, Christmas, Easter, Diwali, Chinese New Year and Eid al-Adha) versus the rest of the year. We estimated IRRs and 95% confidence intervals (CIs) using Poisson regression. RESULTS: Data were collected for 1390 pediatric cases of anaphylaxis between 2011 and 2020. Their median age was 5.4 years, and 864 (62.2%) of the children were boys. During Halloween and Easter, there were higher rates of anaphylaxis to unknown nuts (IRR 1.66, 95% CI 1.13-2.43 and IRR 1.71, 95% CI 1.21-2.42, respectively) and peanuts (IRR 1.86, 95% CI 1.12-3.11 and IRR 1.57, 95% CI 0.94-2.63, respectively) compared to the rest of the year. No increased risk of peanut- or tree-nut-induced anaphylaxis was observed during Christmas, Diwali, Chinese New Year or Eid al-Adha. Anaphylaxis induced by unknown nuts, peanuts and tree nuts was more likely in children aged 6 years or older than in younger children. INTERPRETATION: We found an increased risk of anaphylaxis induced by unknown nuts and peanuts during Halloween and Easter among Canadian children. Educational tools are needed to increase awareness and vigilance in order to decrease the risk of anaphylaxis induced by peanuts and tree nuts in children during these holidays

Effectiveness of a Web-Based Self-Help Program for Suicidal Thinking in an Australian Community Sample: Randomized Controlled Trial

Background: Treatment for suicidality can be delivered online, but evidence for its effectiveness is needed. Objective: The goal of our study was to examine the effectiveness of an online self-help intervention for suicidal thinking compared to an attention-matched control program. Methods: A 2-arm randomized controlled trial was conducted with assessment at postintervention, 6, and, 12 months. Through media and community advertizing, 418 suicidal adults were recruited to an online portal and were delivered the intervention program (Living with Deadly Thoughts) or a control program (Living Well). The primary outcome was severity of suicidal thinking, assessed using the Columbia Suicide Severity Rating Scale. Results: Intention-to-treat analyses showed significant reductions in the severity of suicidal thinking at postintervention, 6, and 12 months. However, no overall group differences were found. Conclusions: Living with Deadly Thoughts was of no greater effectiveness than the control group. Further investigation into the conditions under which this program may be beneficial is now needed. Limitations of this trial include it being underpowered given the effect size ultimately observed, a high attrition rate, and the inability of determining suicide deaths or of verifying self-reported suicide attempts.This study was supported by a grant from the Australian National Health and Medical Research Council (NHMRC; GNT1046317) and forms part of the program of research conducted by the NHMRC Centre of Research Excellence in Suicide Prevention (GNT1042580). The funder does not have any role or ultimate authority in the study design; collection, management, analysis, and interpretation of data; writing of the report; or the decision to submit the report for publication. AC is supported by NHMRC Early Career Fellowship 1122544. PB is supported by NHMRC Early Career Fellowship 1083311. HC is supported by NHMRC Fellowship 1056964

Changes in the visual system of teleost fishes during growth and settlement: an ecological perspective

Nearly all tropical teleost fishes have a pelagic larval phase. Species that settle to a demersal reef-associated mode of life experience dramatic changes in habitat and light environment at this time. In many cases, behaviour associated with feeding, predator avoidance and diel activity also changes. These changes are often rapid, overnight, events. The growth of the eye and extent to which the visual system of larval fishes alters during settlement was investigated in fish with ecologically differing adult lifestyles.\ud \ud The ocular morphology of 18 species of tropical teleosts caught from a variety of locations across the northern Great Barrier Reef, Australia, was examined prior to and following settlement. Detailed retinal cell counts of 6 species with differing post-settlement lifestyles were carried out on fish covering a range of developmental stages. These were: the reef fish Stethojulis strigiventer (Family Labridae), a microcarnivore; Pomacentrus moluccensis and Pomacentrus bankanensis (Family Pomacentridae), a planktivore and herbivore respectively; Apogon doederleini (Family Apogonidae), a nocturnal planktivore; the inter-reef fish Upeneus tragula (Family Mullidae), a benthic carnivore; and the inshore planktivore Ambassis vachelli (Family Ambassidae). A microspectrophotometric investigation of the visual pigment compliment of Upeneus tragula was carried out over the settlement period. In addition microspectrophometric measurements obtained from the adults of four additional tropical teleosts are presented.\ud \ud Fish that settled at small and intermediate sizes showed changes in retinal cell densities prior to settlement which appeared to be in anticipation of the post-settlement lifestyle. Upeneus tragula, a species that remained pelagic for an extended period was found to maintain adaptations for a pelagic lifestyle in both structural and visual pigment compliment. At settlement the retina of this species under went rapid changes in structure as a double layer of cones in the dorsal retina amalgamated to form a single layer. The loss of long-wavelength sensitivity also occurred at this time.\ud \ud The theoretical ability of an eye to resolve fine detail improved rapidly as eye size increased. Mechanisms for increasing sensitivity in nocturnal species were found. These included an increase in rod densities and a lowering of Matthiessen's ratio. The ocular features found in the variety of fish examined were considered in relation to the light environment and behaviours of the fish at respective phases of their life history

Guidelines for the treatment of alcohol problems.

Contents: Chapter 1: Introductory comments 13 • Purpose of the Guidelines 13 • Audience for the Guidelines 14 • Levels of Evidence 14 Chapter 2: Access to treatment: overcoming barriers 21 Chapter 3: Screening and assessment 25 • The need for screening 25 • In-depth assessment before more intensive treatment 33 Chapter 4: Patient-treatment matching 55 Chapter 5: Alcohol withdrawal management 59 • Alcohol withdrawal syndrome 59 • Medical care for alcohol withdrawal complications 61 • Home-based, outpatient and inpatient withdrawal management 69 • Supervised medicated and non-medicated withdrawal management 73 Chapter 6: Post-withdrawal treatment setting 83 • Who should receive residential treatment? 84 • Potential improvements to residential/therapeutic community care 86 Chapter 7: Brief interventions 91 Chapter 8: Psychosocial interventions 99 • Characteristics of effective clinicians 99 • Counselling 100 • Motivational interviewing 103 • Cognitive-behavioural interventions 107 • Skills training 108 • Behavioural self-management 112 • Cognitive restructuring 114 • Cue exposure 116 • Couples and family therapy 117 • Self-guided materials 120 • Standardised versus tailored treatment 121 Chapter 9: Relapse prevention 127 • Identifying factors associated with relapse 127 • Strategies for assessing relapse risk 128 • Reducing the risk of relapse 129 • Pharmacotherapies for relapse prevention 130 Chapter 10: Extended care 145 • Treatment retention 145 • Alcoholics Anonymous 145 • Assertive outreach and structured aftercare 147 Chapter 11: Interventions for specific client groups 151 • Adolescents and young adults 151 • Cognitive impairment 155 • Comorbid disorders 158 • Gender 161 • Indigenous clients 164 Chapter 12: How to put it together 169 • When there is no time available 172 • Brief, one session, face-to-face interventions 172 • Brief outpatient interventions 173 • Longer multi-session outpatient interventions 174 • Brief inpatient/residential withdrawal management 175 • Day patient and inpatient/residential interventions 175 References 179 Appendices 19

Metamorphosis of the visual and barbel sensory systems at settlement in the reef fish Upeneus tragula (Family Mullidae)

Settlement for a reef fish involves a major change in sensory stimuli as the fish undergoes metamorphosis and moves from planktonic to demersal existence. This study examines the nature of structural changes in the sensory system at settlement for the goatfish Upeneus tragula (Family Mullidae). Pelagic-stage fish were collected using purse-seines around aggregation rafts or in light traps off Lizard Island, on the Northern Great Barrier Reef, during the summers of 1989/90 and 1990/91. Settled fish were caught from the reef using fence-nets. Changes in the visual system and out-growths of the olfactory and gustatory system (barbels) were examined in detail, using various morphometric and histological techniques. Major changes were found to occur in both systems. An unusual double-layer of cone photoreceptors and high densities of bipolar (neural processing) cells were found in the dorsal retina during the pelagic stages; this double-cone layer was lost, and both the cone and bipolar cell densities reduced during the 6-12 h settlement period. This may represent an overall reduction in relative visual acuity. Sensory barbels, which aid in the detection and manipulation of prey items once settled, underwent rapid growth at settlement, largely due to the expansion of taste bud cells. These changes to the sensory system are likely to be linked to the changes in environmental stimuli which occur during settlement