bluuebunny/crossref_metadata_2025 huggingface dataset:
Metagenomic investigation of the equine faecal microbiome reveals extensive taxonomic diversity
Authors: Gilroy Rachel , Leng Joy , Ravi Anuradha , Adriaenssens Evelien M. , Oren Aharon , Baker Dave , La Ragione Roberto M. , Proudman Christopher , Pallen Mark J.
Published: March 2022

Background

The horse plays crucial roles across the globe, including in horseracing, as a working and companion animal and as a food animal. The horse hindgut microbiome makes a key contribution in turning a high fibre diet into body mass and horsepower. However, despite its importance, the horse hindgut microbiome remains largely undefined. Here, we applied culture-independent shotgun metagenomics to thoroughbred equine faecal samples to deliver novel insights into this complex microbial community.

Results

We performed metagenomic sequencing on five equine faecal samples to construct 123 high- or medium-quality metagenome-assembled genomes from Bacteria and Archaea. In addition, we recovered nearly 200 bacteriophage genomes. We document surprising taxonomic diversity, encompassing dozens of novel or unnamed bacterial genera and species, to which we have assigned new Candidatus names. Many of these genera are conserved across a range of mammalian gut microbiomes.

Conclusions

Our metagenomic analyses provide new insights into the bacterial, archaeal and bacteriophage components of the horse gut microbiome. The resulting datasets provide a key resource for future high-resolution taxonomic and functional studies on the equine gut microbiome.
Knowledge, attitudes and perceptions regarding human papillomavirus among university students in Hail, Saudi Arabia
Authors: Alshammari Farhan , Khan Kashif Ullah
Published: March 2022

Background

Human papillomavirus (HPV) is a well-known cause of cervical cancer. The prevalence of HPV, insufficient preventive services, inadequate treatment access, socioeconomic conditions, certain cultural causes and values and opinions regarding cervical cancer have been established as factors contributing to the occurrence of cervical cancer in various parts of the world.

Objective

To determine university students’ knowledge, attitudes and perceptions regarding HPV and its vaccine.

Material and Methods

The present cross-sectional study included students enrolled at the University of Hail, Saudi Arabia. Data were collected from January to May 2020 using a previously validated 26-item questionnaire.

Results

A total of 386 participants responded to the survey; the response rate was 80%. The majority of the respondents (63%) were male and 332 (86%) respondents were single among the overall study population. Most respondents were aged 21–25 years (75.6%), followed by 26–30 years (12.7%). In total, 130 (33.7%) respondents reported that they had heard of HPV before, while 174 (45.1%) reported that HPV infections are rare in Saudi Arabia. Furthermore, 102 (26.4%) respondents thought that HPV causes genital warts, while almost 29.5% believed that HPV infection is a sexually transmitted disease. Nearly 76.2% of the respondents did not believe that HPV infection can occur without symptoms. Moreover, 53.4% of the respondents stated that they did not know the health problems associated with HPV infection, while 148 (38.8%) stated that cervical cancer is a health problem associated with HPV infection. When asked about their understanding of the HPV vaccine, nearly 267 (62.2%) respondents believed that there is no vaccine for HPV, while 239 (61.9%) believed that the vaccine does not minimise the risk of cervical cancer. In addition, the respondents reported that they would be far more likely to get an HPV vaccine if recommended by their doctors [relative importance index (RII) = 0.745], followed by their friends (RII = 0.675).

Conclusion

The present findings provide a clear understanding of university students’ knowledge, perceptions and attitudes regarding HPV; this information can be used to raise awareness by developing an effective educational strategy. However, further research with a larger sample size is recommended; such efforts would also aid in the development of educational services for various age ranges.
RapidHRV: an open-source toolbox for extracting heart rate and heart rate variability
Authors: Kirk Peter A. , Davidson Bryan Alexander , Garfinkel Sarah N. , Robinson Oliver J.
Published: March 2022

Heart rate and heart rate variability have enabled insight into a myriad of psychophysiological phenomena. There is now an influx of research attempting using these metrics within both laboratory settings (typically derived through electrocardiography or pulse oximetry) and ecologically-rich contexts (via wearable photoplethysmography, i.e., smartwatches). However, these signals can be prone to artifacts and a low signal to noise ratio, which traditionally are detected and removed through visual inspection. Here, we developed an open-source Python package, RapidHRV, dedicated to the preprocessing, analysis, and visualization of heart rate and heart rate variability. Each of these modules can be executed with one line of code and includes automated cleaning. In simulated data, RapidHRV demonstrated excellent recovery of heart rate across most levels of noise (>=10 dB) and moderate-to-excellent recovery of heart rate variability even at relatively low signal to noise ratios (>=20 dB) and sampling rates (>=20 Hz). Validation in real datasets shows good-to-excellent recovery of heart rate and heart rate variability in electrocardiography and finger photoplethysmography recordings. Validation in wrist photoplethysmography demonstrated RapidHRV estimations were sensitive to heart rate and its variability under low motion conditions, but estimates were less stable under higher movement settings.
ATP11A promotes EMT by regulating Numb PRRL in pancreatic cancer cells
Authors: Chen Lin , Tang Jingtong , Sheng Weiwei , Sun Jian , Ma Yuteng , Dong Ming
Published: March 2022

Purpose

The Numb protein plays a vital role in tumor development. The main aim of this study was to identify ATP11A, which is associated with the biological behavior of pancreatic cancer, and elucidate its relationship with Numb and the underlying mechanism behind this relationship.

Methods

First, data retrieved from The Cancer Genome Atlas (TCGA) and Genotype-Tissue Expression (GTEX) databases was used to investigate the expression of ATP11A mRNA and its relationship with Numb mRNA in pancreatic cancer. Western blot assays on 31 pairs of pancreatic cancer tissues and paracancerous tissues, and immunohistochemical assays on 81 pancreatic cancer specimens were performed in order to verify the expression of ATP11A in pancreatic cancer at the protein level. Next, ATP11A was overexpressed or knocked down to observe its effects on the invasion and migration ability of pancreatic cancer cells and the changes of downstream proteins. Rescue assays were conducted to determine the mechanism through which ATP11A affects Numb, ZEB1, Snail2 and other proteins. Furthermore, immunoprecipitation assays were performed to explore the interaction between ATP11A and Numb. Finally, pancreatic cancer cells were stimulated with TGFB1 and ATP11A expression was examined to explore whether the effect of ATP11A on EMT was TGFB dependent.

Results

At the mRNA level, the expression of ATP11A in pancreatic cancer tissues was significantly higher than in normal pancreatic tissues (P < 0.001). ATP11A expression was also highly correlated with Numb expression (R = 0.676). At the protein level, ATP11A expression in pancreatic cancer tissues was significantly higher than that in paracancerous tissues (P = 0.0009), and high ATP11A expression was also correlated with a worse prognosis. Moreover, our results showed that ATP11A can promote the invasion and migration of pancreatic cancer cells. Additionally, ATP11A could positively regulate the expression of Numb PRRL, Snail2 and ZEB1 proteins. The rescue experiment results showed that the enhancement effect of ATP11A on ZEB1/Snail2 was suppressed by the specific knockdown of Numb PRRL. In addition, the immunoprecipitation results showed that ATP11A could specifically bind to Numb PRRL. The expression of ATP11A was also upregulated after TGFB stimulation, suggesting that the effect of ATP11A on EMT is TGFB dependent.

Conclusion

ATP11A is significantly upregulated in pancreatic cancer tissues, where it promotes the invasion and migration ability of pancreatic cancer cells. It is also associated with adverse prognosis in pancreatic cancer. Furthermore, ATP11A affects the epithelial-to-mesenchymal transition (EMT) of pancreatic cancer by regulating the TGFB dependent Numb PRRL-ZEB1/Snail2 pathway.
The 100 Most Cited Publications on Dental Ceramics between 1980 To 2020: A Bibliometric Analysis
Authors: Shah Naisargi , Badwaik Praveen , Shah Prakruti , Jadhav Sheetal , Bhatnagar Vishrut , Idrisi Arshad
Published: March 2022

Introduction: Evidence-based dentistry provides clinically oriented decisions with the help of available scientific data and literature. The significance of an article is reflected by its citation count, the impact it has on clinical practice. This is where bibliometric studies play an important role by providing an overview of research and scientific activity by calculating bibliometric indicators that give information about the quantity of published research in a specific field. The citation index is considered an important parameter for measuring relevance in a specific field. Articles that are heavily cited are considered important in the field of dental ceramics as they can provide basic information, recent advances, and the areas that are extensively researched. Aim: To perform a bibliometric analysis of the 100 most cited publications in the field of dental ceramics, in the past 40 years from 1980 to 2020. Materials and Methods: The Scopus database was used to retrieve all publications with titles containing the term “Dental Ceramics”. Thereafter, the data obtained was arranged in a descending order and a list of the 100 most cited publications were prepared. The data was analysed for the number of citations, the journals in which they were published, its impact factor, the work of the author, country in which it was published, document type retrieved, university affiliation, funding sponsors, area of subject in study, and the number of articles published per year. Prediction of future growth trend was also analysed using data gathered in Microsoft Excel software. Results: Out of the retrieved data, 3815 was the highest number of citations recorded. Two of the articles received more than 1000 citations and 32 articles were cited less than 100 times. These 100 publications were documented form the year 1986 to 2018. Largest number of publications were made in the Journal of Dental Materials (n=31), followed by the Journal of Prosthetic Dentistry (n=12) and Journal of Dental Research (n=10). 85 of the total documents were original articles, 12 were reviews, two cited publications were books and one was a conference paper. Conclusion: The bibliometric analysis of the 100 most cited articles revealed a marked change in the trends and progress that has taken place in the field of dental ceramics amongst the researchers, clinicians and technicians.
COVID-19 Vaccine Behaviour among People Attending a Tertiary Care Center, Punjab, India
Authors: Garg Ravi Kumar , Garg Kranti , Gupta Nitin , Chopra Vishal , Gupta Ankur
Published: March 2022

Introduction: Coronavirus Disease 2019 (COVID-19) appropriate behaviour and vaccination are two critical defenses in the fight against this pandemic. As these need to be followed religiously, this preventive behaviour should be thoroughly investigated. Aim: To examine the COVID-19 vaccine behaviour amongst people attending tertiary care centre at Patiala, Punjab, India. Materials and Methods: A cross-sectional study was conducted on 200 individuals attending the Outpatient Department of Government Medical College at Patiala, Punjab, India, from 15th July to 22nd July 2021. Individuals were administered sociodemographic questionnaire, General Health Questionnaire-12- Hindi version (GHQ-12), and COVID-19 vaccine related and COVID-19 appropriate behavior related questionnaire. Actual observation by the clinician regarding proper use of face masks, hand hygiene and social distancing was done and objectively scored on 0-10 for each item with a scale interval of 2. Analysis was conducted using IBM Statistical Package for the Social Sciences (SPSS) version 22.0. Results: Only 40% individuals were vaccinated. After eligibility, there was a mean delay of 4.20±3.51 weeks (median: 4 weeks) and 13.40±3.33 weeks (median: 12 weeks) in the vaccinated and unvaccinated individuals. Out of 120, 86 unvaccinated participants planned to get vaccinated in future. Significantly lower scores were obtained for actually observed COVID-19 appropriate behaviour (proper mask usage, hand hygiene and social distancing) as noted by the clinician vs the scores as reported by the participants. Conclusion: There were few takers for the COVID-19 vaccine, even weeks after eligibility. The COVID-19 appropriate behaviour was largely not being followed properly and the false sense of following the same complicated issues further. With multiple waves of the pandemic one after the other, and booster doses of vaccination, there is still an urgent need to sensitise the population at the grass root level regarding the COVID-19 vaccine behaviour to fight this pandemic.
Association between Oral Probiotic Streptococcus Supplements and Salivary Streptococcus Mutans Count in Human Study: A Systematic Review
Authors: Poorni Saravanan , Nivedhitha MS , Srinivasan Manali Ramakrishnan , Arthi B
Published: March 2022

Introduction: Probiotics in caries prevention is a subject of growing interest due to their specific activities and inhibitory effects on the cariogenic organisms. Though numerous reviews have evaluated the effect of probiotics in caries prevention, very few have focussed on the probiotic streptococcus strains, none of them have emphasised on the effect of probiotic Streptococcus strains on the salivary Streptococcus mutans count. Aim: To evaluate the current literature on the association between oral probiotic Streptococcus supplements on the Streptococcus mutans level. Materials and Methods: A focused PICO question was formulated. Comprehensive literature searches were independently performed by two reviewers in various electronic databases. Randomised control trials in humans in which oral probiotic Streptococcus supplements were used to alter the salivary Streptococcus mutans count were included. Risk of bias and data extraction of the included articles was performed. Results: Five studies were included in the qualitative synthesis. The quality of the included studies was quite low as only one among the five studies had moderate risk of bias while all others had a high risk of bias. Conclusion: Within the limitations of the available data, it can be concluded that probiotic Streptococcus supplements have a positive effect on reducing the Streptococcus mutans levels as long as they are being used.
Single point mutation in the Rieske iron–sulfur subunit of cytochrome b6/f leads to an altered pH dependence of plastoquinol oxidation in Arabidopsis
Authors: Jahns Peter , Graf Maria , Munekage Yuri , Shikanai Toshiharu
Published: July 2002

The pgr1 mutant of Arabidopsis thaliana carries a single point mutation (P194L) in the Rieske subunit of the cytochrome b
6/f (cyt b
6/f) complex and is characterised by a reduced electron transport activity at saturating light intensities in vivo. We have investigated the electron transport in this mutant under in vitro conditions. Measurements of P700 reduction kinetics and of photosynthetic electron transport rates indicated that electron transfer from cyt b
6/f to photosystem I is not generally reduced in the mutant, but that the pH dependence of this reaction is altered. The data imply that the pH‐dependent inactivation of electron transport through cyt b
6/f is shifted by about 1 pH unit to more alkaline pH values in pgr1 thylakoids in comparison with wild‐type thylakoids. This interpretation was confirmed by determination of the transmembrane ΔpH at different stromal pH values showing that the lumen pH in pgr1 mutant plants cannot drop below pH 6 reflecting most likely a shift of the pK and/or the redox potential of the oxidised Rieske protein.
Immobilization of Potato Tuber Lipoxygenase on Oxirane Acrylic Beads
Authors: del Carmen Pinto María , Gata José Luis , Macías Pedro
Published: July 2002

In this study, lipoxygenase from potato tuber has been purified by a method involving hydrophobic chromatography and the purified enzyme immobilized by covalent coupling to oxirane acrylic beads. The immobilized lipoxygenase exhibited increased long‐term stability without a significant modification of the kinetic parameters. The comparative study on the effects of inhibitors such as dithizone, NDGA, phenidone, and β‐mercaptoethanol on the free and immobilized enzyme highlighted the importance of the lipoxygenase−support interaction, concluding that the immobilization process could cause the protection of the iron atom in the enzyme. The enzymatic specificity was maintained for the immobilized lipoxygenase, and their stability increased as compared to the free enzyme, making it feasible to use the enzyme in a multistep reaction to produce large quantities of leukotriene A4 or other related compounds of interest in the chemical industry and medicine.
X‐ray and13C solid‐state NMR studies ofN‐benzoyl‐phenylalanine
Authors: Potrzebowski M.J. , Tekely P. , Błaszczyk J. , Wieczorek M.W.
Published: July 2002

Abstract:A crystalline sample ofN‐benzoyl‐dl‐phenylalanine1and a polycrystalline sample ofN‐benzoyl‐l‐phenylalanine2were studied using13C high‐resolution solid‐state NMR spectroscopy. The X‐ray structure of thedlform was established. Sample1crystallizes in a monoclinic form with a P21/c space group,a = 11.338(1) Å,b = 9.185(1) Å,c = 14.096(2) Å, β = 107.53(3)°,V = 1400(3) Å3,Z = 4 andR = 0.053. The principal elements of the13C chemical shift tensors δiifor1and2, selectively13C (99%) labeled at the carboxyl groups were calculated. On the basis of13C δiianalysis the hydrogen bonding pattern for sample2was deduced. Enriched samples were used to establish the intermolecular distance between chemically equivalent nuclei for1and spatial proximity in heterogeneous domain for2, employing the ODESSA pulse sequence. The consistence of the complementary approach covering X‐ray data, analysis of the13C δiiparameters and ODESSA results is revealed.
Expression of solute carrier 7A4 (SLC7A4) in the plasma membrane is not sufficient to mediate amino acid transport activity
Authors: WOLF Sabine , JANZEN Annette , VÉKONY Nicole , MARTINÉ Ursula , STRAND Dennis , CLOSS Ellen I.
Published: July 2002

Member 4 of human solute carrier family 7 (SLC7A4) exhibits significant sequence homology with the SLC7 subfamily of human cationic amino acid transporters (hCATs) [Sperandeo, Borsani, Incerti, Zollo, Rossi, Zuffardi, Castaldo, Taglialatela, Andria and Sebastio (1998) Genomics 49, 230–236]. It is therefore often referred to as hCAT-4 even though no convincing transport activity has been shown for this protein. We expressed SLC7A4 in Xenopus laevis oocytes, but could not detect any transport activity for cationic, neutral or anionic amino acids or for the polyamine putrescine. In addition, human glioblastoma cells stably overexpressing a fusion protein between SLC7A4 and the enhanced green fluorescent protein (EGFP) did not exhibit an increased transport activity for l-arginine. The lack of transport activity was not due to a lack of SLC7A4 protein expression in the plasma membrane, as in both cell types SLC7A4-EGFP exhibited a similar subcellular localization and level of protein expression as functional hCAT-EGFP proteins. The expression of SLC7A4 can be induced in NT2 teratocarcinoma cells by treatment with retinoic acid. However, also for this endogenously expressed SLC7A4, we could not detect any transport activity for l-arginine. Our data demonstrate that the expression of SLC7A4 in the plasma membrane is not sufficient to induce an amino acid transport activity in X. laevis oocytes or human cells. Therefore, SLC7A4 is either not an amino acid transporter or it needs additional (protein) factor(s) to be functional.
Glucose transport regulation by p210 Bcr–Abl in a chronic myeloid leukaemia model
Authors: Bentley J. , Walker I. , McIntosh E. , Whetton A. D. , Owen‐Lynch P. J. , Baldwin S. A.
Published: July 2002

The regulation of nutrient transport by both cytokines and oncogenes has been linked to haemopoietic cell survival. In this study, we found that activation of Bcr–Abl protein tyrosine kinase was associated with the stimulation of glucose transport in the multipotent haemopoietic cell line FDCP‐mix, a cell model for chronic‐phase chronic myeloid leukaemia (CML). Bcr–Abl upregulation of glucose transport was mediated by phosphatidylinositol‐3‐kinase. The observation that Bcr–Abl can regulate glucose transport in a CML cell model raises the possibility that glucose transport regulation may have a role to play in the aberrant survival of stem cells in the chronic phase of CML.
Hyperleptinaemia in young adults following cranial irradiation in childhood: growth hormone deficiency or leptin insensitivity?
Authors: Brennan  , Rahim  , Blum  , Adams  , Eden  , Shalet
Published: July 2002

OBJECTIVE

In order to explore the mechanism of obesity in long‐term survivors of childhood leukaemia, fat mass, lean body mass and serum leptin were assessed in a cohort of 32 (17 males) adults who had received cranial irradiation (XRT) in childhood as part of their treatment for acute lymphoblastic leukaemia (ALL), and compared with 35 age and body mass index (BMI) matched young adults (18 male).

DESIGN

Thirty‐one patients and 18 controls had fat mass and lean body mass assessed by dual x‐ray absorptiometry (DEXA), using a lunar DPX‐L scanner. Serum leptin concentrations were also measured in 27 patients and all controls. Growth hormone status had previously been determined using an insulin tolerance test and arginine stimulation test. Nine patients were classified as severe growth hormone (GH) deficient (group 1), 12 patients as GH insufficient (group 2) and 11 patients as normal (group 3).

RESULTS

BMI and absolute fat mass were not significantly different between the patients and controls regardless of their gender (P = 0.1 and P = 0.14 respectively). In contrast, absolute lean mass was significantly reduced (P < 0.01) and leptin concentrations were significantly increased (P < 0.001) in patients compared with controls. BMI, fat mass and leptin concentrations but not lean mass were significantly different between the three GH status groups (P < 0.01, P < 0.01, P = 0.004, and P = 0.67 respectively). When leptin concentrations were expressed per unit of fat mass, they were increased in the patients compared with the controls (P = 0.03) with significant differences between the GH status groups (P = 0.004), being significantly higher in the severe GH deficient group.

CONCLUSIONS

Young adults who receive cranial irradiation in childhood are prone to GH deficiency and hyperleptinaemia. The pathophysiological significance of the hyperleptinaemia remains to be established but it has occurred either as a consequence of radiation induced hypothalamic damage or GH deficiency.
Vascular reactivity in acromegalic patients: preliminary evidence for regional endothelial dysfunction and increased sympathetic vasoconstriction
Authors: Maison Patrick , Démolis Pierre , Young Jacques , Schaison Gilbert , Giudicelli Jean‐François , Chanson Philippe
Published: July 2002

BACKGROUND AND OBJECTIVES

Hypertension is found in one‐third of acromegalic patients. An heterogenous distribution of cardiac output has been recently demonstrated in acromegalic patients with an increased blood flow at the level of the upper limb, suggesting that acromegalic patients may have some degree of endothelial dysfunction. Elsewhere, studies involving hypopituitary GH‐deficient adults have shown that GH and/or IGF‐I may have direct effect on endothelial function.

SUBJECTS AND METHODS

We thus compared cutaneous vasoreactivity responses in 10 normotensive patients with active acromegaly (A) (six women and four men) aged 25–59 (mean, 43.2 years), whose basal GH and IGF‐I levels ranged from 7.4 to 158 mU/l and from 401 to 1690 μg/l, respectively, and in 10 normal age‐ and sex‐matched controls (NC) by means of Laser Doppler flowmetry at the levels of the palm and the dorsum of the right hand. Circulatory skin velocities were studied basally and after increasing skin temperature to 44 °C (in order to study direct nonspecific vasodilatation response which is independent of endothelial or autonomous nervous system and reflects normal vascular muscle function), after shear‐stress (known to produce flow‐dependent vasodilatation, mediated by nitric oxyde (NO) originating from endothelial cells) and after cold‐stress applied on the opposite hand (known to produce vaso‐constriction mediated by the sympathetic nervous system).

RESULTS

The warm test induced a significant (P < 0.001) and similar increase in both dorsal and palmar skin perfusion in A (mean± SD) (240 ± 96 and 238 ± 134%, respectively) and NC (232 ± 137 and 233 ± 73, respectively). Ischaemia release induced a significant increase in both dorsal and palmar skin blood flows in the two groups (P < 0.001), but reactivities in acromegalic patients were about one half of those measured in controls (22.9 ± 16.2% (A)vs. 46.9  25% (NC), 2P < 0.02, at the level of the dorsum; and 45.0 ± 43.6% (A)vs. 104.7 ± 40.1 (NC), 2P < 0.01, at the level of the palm). Cold pressor test resulted in significant decreases in both cutaneous flows (P < 0.01) in the two groups, with a larger vasoconstriction (that did not reach statistical significance) in acromegalic patients as compared with controls (P < 0.10).

CONCLUSION

Vascular smooth cell ability to produce skin vasodilatation is normal but endothelium‐dependent vasodilatation appears to be impaired while sympathetic‐mediated vasoconstrictive response might be increased in acromegaly. This endothelial dysfunction may contribute to hypertension and represent a risk factor for cardiovascular complications in acromegaly.
The reintroduction of the swift fox Vulpes velox to South Central Saskatchewan, Canada
Authors: Smeeton Clio , Weagle Ken
Published: July 2002

The Canadian Swift Fox Reintroduction Programme lasted from 1972 to 1997. From 1983 to 1997, a total of 841 captive-raised swift foxes and 91 translocated swift foxes were released in the Canadian Prairies. In South Central Saskatchewan, 406 captiveraised animals and 14 translocated animals were released from 1990 to 1997. This area was used to develop new release methods (in particular, portable protective shelters (PPS)) and saw the co-operation of a nongovernmental organization (NGO) (Cochrane Ecological Institute (CEI)) with two levels of government (Heritage Canada (Grasslands National Park) and the Government of Saskatchewan). A 1996–97 survey of swift foxes in South Central Saskatchewan estimated the population to be 87 animals. No attempt has been made to establish if this population level is sustainable.
Microstructure variation in sponges sharing growth form: The encrusting demospongesDysidea avaraandCrambe crambe
Authors: Galera Jordi , Turon Xavier , Uriz María J. , Becerro Mikel A.
Published: July 2002

The goals of this study are to assess variability of microarchitecture in sponges with a similar growth form and to look for correlates between microstructural organization, biological functions and ecological strategies. A comparison of the microstructure of the encrusting spongesDysidea avara(Dendroceratida) andCrambe crambe(Poecilosclerida) is performed. The species co‐occur in sublittoral habitats of the western Mediterranean. Histological techniques, image analysis and corrosion castings are used in order to quantify thickness, degree of development of the aquiferous system, relative amount of structural and cellular materials, and size of the choanocyte chambers in both species. The fine structure and cellular types are described and analysed through SEM/TEM. These sponges are known to feature contrasting ecological strategies:D. avarahas higher growth and clearance rates thanC. crambe, it is more susceptible to predation and uses a more opportunistic strategy of space acquisition and maintenance.C. crambegrows slowly, it is chemically protected from predation and it competes successfully for space with other invertebrates. These differences in biological strategies are here shown to have clear structural correlates:D. avarais structurally simpler, with fewer cell types and very scarce matrix material. Most of its section is occupied by the highly developed aquiferous system. Its construction is much looser than inC. crambe. In the latter species, structural complexity is higher, it produces long‐lasting structures such as the spicules, and it is more compact and thinner. It is concluded that there is wide scope for microarchitectural patterns, even in species with similar growth form, and that structural and cytological characters may prove to be useful descriptors of biological strategies in sponges.
Predicting the occurrence of diabetes mellitus in recipients of heart transplants
Authors: Depczynski B. , Daly B. , Campbell L. V. , Chisholm D. J. , Keogh A.
Published: July 2002

AimsTo establish the incidence of post‐transplant diabetes mellitus (PTDM) and factors predictive of its development.

MethodsThis was a retrospective review (using hospital records and transplant database) of 97 consecutive adult patients who underwent cardiac transplantation at St Vincent’s Hospital, Sydney, Australia.

ResultsMean follow‐up was 27 months. Excluding five patients who had pre‐existing diabetes, the cumulative incidence of PTDM was 15.7%. Pre‐transplant random blood glucose (5.6 ± 0.8 vs. 5.2 ± 0.6 mmol/l,P < 0.05), family history (46% vs. 15%,P < 0.05) and a continuing requirement for insulin on the second post‐transplant day (54% vs. 15%,P < 0.01) differed in those who developed PTDM as opposed to those who remained free of diabetes. Patients who developed PTDM had received slightly higher mean doses of prednisolone at three months (0.21 ± 0.03 vs. 0.19 ± 0.03 mg. kg−1.day−1,P < 0.01). Of the factors identifiable prior to initial hospital discharge, only family history of diabetes mellitus and second post‐transplant day insulin requirement independently predicted the occurrence of PTDM.

ConclusionsA family history of diabetes and the need for insulin beyond the first 24 h after transplantation are factors identifiable prior to hospital discharge, which predict patients at risk of developing PTDM. In such patients, consideration to minimizing the dose of glucocorticoids should be given where possible.
Corneal swelling and recovery following wear of thick hydrogel contact lenses in insulin‐dependent diabetics
Authors: Skaff Amanda , Cullen Anthony P. , Doughty Michael J. , Fonn Desmond
Published: July 2002

Thick, 0.34 mm, 38% water hydrogel lenses were fitted, under a pressure patch, no one eye of 18 type I diabetic patients (aged 18–40 years) to assess the acute response to hypoxia and hypercapnia; the response was compared with that in 18 healthy, aged‐matched non‐diabetic subjects; the closed‐eye lens wear was started mid‐morning. Pre‐lens wear assessments were made of acuity, intraocular pressure (IOP), central corneal thickness (CCT) and corneal appearance by biomicroscopy. The mean duration of the diabetes was 13 ± 7 years and the average fasting blood glucose was 8.7 ± 3.3 mM l−1. Baseline CCT values were marginally greater in diabetic patients (600 ± 33 μm) compared with a group of non‐diabetic control subjects (584 ± 26 μm; P > 0.5). A 7.7 ± 2.1% increase in CCT was measured after 3 h lens wear in the diabetic patients while an average 10.6 ± 2.4% increase in CCT was measured in the control subjects (P < 0.05). The recovery of corneal thickness to baseline values in diabetic patients was slower (at 44.8 ± 2.0% per hour) than the control subjects (53.9 ± 2.1 per hour; P < 0.05) although recovery of corneal thickness occurred in both groups within 2.5–3 h. IOP values (non‐contact tonometry) were higher in the diabetic patients than in the controls (14.5 ± 2.9 vs 12.4 ± 1.7 mmHg; P < 0.01). Overall, those corneas with greater baseline CCT values tended to swell less than those with lower baseline CCT values (r = 0.582). Positive correlations were also found between corneal thickness and IOP and blood glucose. The diabetic patients thus tended to have slightly thicker corneas (but this could be related to blood glucose or IOP rather than true corneal disease) and also had corneas that tended to swell less with a contact lens stress test (but this could be constitutively due to the slight oedema already present). The different corneal response in diabetic patients may thus be the result of physical determinants such as initial oedema and IOP and not the result of a disease of the cornea itself.
The Pulfrich effect in optometric practice
Authors: Heron G. , McQuaid Maire , Morrice Elizabeth
Published: July 2002

The Pulfrich effect can occur spontaneously, giving severe symptoms of changed visual perception in a variety of conditions in which an interocular latency difference has occurred. The symptoms principally involve misjudgements on the location of objects, especially when driving. Interocular latency differences can inadvertently be created in patients in practice and this study has investigated the Pulfrich effect in anisocoria, uniocular mydriasis, and with uniocular tint (X‐chrom lens). In all cases a Pulfrich effect was consistently evident and compared to the size of the effect provoked by neutral density filters. The results show that with anisocoria, uniocular mydriasis and the X‐chrom lens, the provoked Pulfrich effect is similar to that found reported previously in cases of trauma. These cases had severe visual symptoms so that care should be exercised in practice, where procedures likely to provoke the Pulfrich effect are contemplated. Specifically, patients who have received uniocular mydriasis in practice should be cautioned about the possible visual effects and advised not to drive until the effect of the mydriatic has finished and equal pupil sizes have been restored.
Night driving: effects of glare from vehicle headlights on motion perception
Authors: Anderson Stephen J. , Holliday Ian E.
Published: July 2002

Elderly drivers often experience disability glare at night from the headlights of oncoming vehicles. To assess the effect of glare from vehicle headlights on visual performance for seeing moving targets, experiments were performed at night on a dimly lit road with observers seated in a stationary motor car viewing a computer‐generated stimulus display at a distance of 23 m (the stopping distance for 50 kph). The display was set 2 m to the side of a second stationary car whose position on the road was that of an oncoming vehicle with respect to the observer. The headlights of the observer's car were on low‐beam while those of the opposing car were switched off (control condition), on low‐beam or on high‐beam. Experiments were performed using mean display luminances of 50 cd/m2 and 0.5 cd/m2. Spatial contrast sensitivity functions for the directional discrimination of drifting (8 Hz) sinusoidal gratings were measured using three different viewing conditions: normal vision (binocular visual acuity (BVA) = 6/6); blurred vision (BVA = 6/9‐); and simulated intraocular lens opacities (BVA =6/6 ‐). The data were fitted with an exponential function, which was extrapolated to 100% contrast to estimate dynamic visual acuity. The results show that simulated lens opacities, which have little or no effect on standard day time measures of visual acuity, have a marked effect on night‐time measures of contrast sensitivity for moving targents. Taking into account the average luminance of objects lit by road lighting, we estimate that high‐beam glare reduces maximum contrast sensitivity by an order of magnitude in persons affected by mild lens opacities, giving a dynamic acuity of 1.0 c/deg (6/180 Snellen equivalent) or less. From this and other studies we argue that there is now a strong case for the introduction of vehicle‐licensing sight re‐testing at regular intervals in the UK. In addition, we suggest that vehicle‐licensing authorities consider the feasibility of introducing sight tests under night‐time driving conditions.
Varifocal contact lenses for the correction of presbyopia
Authors: Port Michael , Refson Kathleen , Minards Jane
Published: July 2002

A Nissel + 1.75 D PS45 lens' label power seems to be made up of about + 0.75 D distance and + 0.75 D near addition. There are individual variations which will depend on pupil size, corneal shape, lens position and ocular aberrations. When a + 0.75 Bausch & Lomb U3 lens was used as a control, there was also a significant increase in ‘accommodation’ measured (+ 0.75 D), but this could not be explained. When two other lenses with an aspheric surface were studied, they also showed a near addition effect. In this supplementary study the changes were explained by changes in spectacle accommodation. A lens with two spherical surfaces did not show the expected increase in spectacle accommodation. Astigmatism, as a general rule, was not corrected by the PS45 lens, although the very occasional case did show some reduction. Visual acuity and contrast sensitivity at 8 cpd and 3 cpd were not significantly affected when compared to the control lens.
Clinical uses of the scanning laser ophthalmoscope
Authors: Culham Louise , Fitzke Fred , Marshall John G.
Published: July 2002

The scanning laser ophthalmoscope (SLO), designed in the early 1980s, has many advantages over conventional imaging techniques. Continuous, real‐time images are displayed on a TV monitor and usually recorded on video‐tape. Images can be obtained without pupil dilation and it is often possible to image through cataract and other media opacities. The lasers used for retinal imaging, helium‐neon, argon and infra‐red diode, are low powered and the light levels used in the SLO are about 1000 times less than in conventional fundus photography. Fluorescein and indocyanine green angiography can be performed and the dynamic sequences recorded on video‐tape.

Several systems are available, for example Rodenstock, Zeiss and Heidelberg, and each have specific features. Typically the field of view is 20 or 40 degrees. Instruments can work in a non‐confocal, confocal or indirect mode. While the non‐confocal mode is used for general retinal imaging, in the confocal mode, thin slices of a structure can be imaged, e.g. the optic nerve head, and by means of a computer three‐dimensional reconstruction is possible. In the indirect mode, the image is formed from structures that scatter light, e.g. the choroidal vessels.

The SLO also has the ability to perform psychophysical measurement. Any graphics which can be displayed on a TV monitor can be encoded into the scanning laser beam. The stimuli can be altered in character, size, contrast and velocity. The tests that allow assessment of visual function include visual acuity, retinal perimetry and measurements of fixation stability. Scrolled text can be used to allow precise evaluation of reading ability at different retinal locations.

Using these tests we have investigated residual vision in patients with macular disease. Microperimetry was able to define accurately the size and location of retinal lesions and in some patients residual visual function was detected in areas that appeared to be non‐functioning. Some patients had fixation stability which was exceptionally poor whilst in others it was normal. The ability to recognize scrolling text declined with increasing retinal eccentricity and decreasing text contrast. The imaging and psychophysical abilities of SLOs are providing valuable information on patients with retinal diseases.
Blue‐on‐yellow perimetry
Authors: Hudson Chris , Wild John
Published: July 2002

Laboratory based studies which employ foveal stimuli have demonstrated a selective short‐wavelength sensitive (SWS) pathway deficit prior to visual field loss in glaucomatous patients. Early glaucomatous visual field loss as revealed by conventional perimetry, however, is generally accepted to occur outside the fovea. Consequently, blue‐on‐yellow perimetry was developed which permits the assessment of SWS function across the central visual field. This new clinical technique employs a blue stimulus to preferentially stimulate the SWS pathway and a high luminance yellow background to saturate the other receptor types. Clinical studies suggest that blue‐on‐yellow perimetry reveals early glaucomatous field loss before conventional perimetry which follows a pattern dictated by the anatomy of the retinal nerve fibre bundles.

Blue‐on‐yellow perimetry is particularly prone to attenuation by the ocular media and macular pigment because of the use of a short‐wavelength stimulus. Ocular media absorption (OMA) increases with increase in age (approx. a 10 dB increase in mean OMA between 20 and 70 years relative to 410 nm), exhibits a large variation between individuals of the same age (approx. 9 dB) and is exaggerated in diabetics. Both OMA and forward light scatter (LS) result in a diffuse reduction of blue‐on‐yellow sensitivity. Macular pigment absorption (MPA) does not vary systematically with age (P > 0.05) but exhibits a large variation between individuals (approx. 10 dB relative to 460 nm). MPA results in a symmetrical reduction of blue‐on‐yellow sensitivity centred on the fovea (mean foveal MPA 4 dB, P < 0.001) with 5° eccentricity.

The psychophysical techniques employed to quantify OMA, forward LS and MPA are time‐consuming and not suitable as routine clinical procedures. Methods of analysis which avoid the use of absolute sensitivity values need to be employed to identify abnormality in the blue‐on‐yellow visual field. Such an approach may rely on the identification of change in shape (i.e. pattern standard deviation) or symmetry (i.e. glaucoma hemifield test) of the visual field. Alternatively, the clustering of stimulus locations with markedly reduced sensitivity and the conformity of clusters to recognized patterns of glaucomatous nerve fibre loss should provide sensitive measures of abnormality.
Research opportunities in the Hospital Eye Service
Authors: Woodward E. G.
Published: July 2002

An analysis was undertaken of higher degrees by research awarded to optometrists based in the Hospital Eye Service since 1968. When these were considered in conjunction with current registration for higher degrees, it was possible to analyse research areas.

The most popular topics were glaucoma, detection and measurement of progression (5); cornea (4); ocular biometry (3); infant vision and development (3); keratoconus (3); and contact lenses (3).

In recent years, the scope of research has increased considerably and now embraces epidemiology, health economics and interdisciplinary decision making with other healthcare professionals.

Successful completion rates for British College of Optometrist's Scholars for higher degrees for the hospital and university sectors were analysed. The total completion rate was 16/26 (65.4%), university based: 11/20 (55%), and hospital based: 6/6 (100%).
Differences in apparent contrast in yellow and white light
Authors: Rabin LTC Jeff , Wiley Roger
Published: July 2002

The purpose of this study was to investigate suprathreshold contrast perception in white and yellow light. The contrast of black‐on‐white letters was adjusted to match the perceived contrast of yellow‐on‐yellow letters presented simultaneously on a video display. At lower contrasts (7–15%), the apparent contrast of yellow letters was slightly enhanced compared to black‐on‐white letters (mean enhancement = 23%), but this effect diminished with increasing contrast. The slight enhancement in yellow light was independent of letter size, and could not be explained by luminance differences between yellow and white displays. This effect may relate to the subjective improvement often reported when wearing yellow (blue‐blocking) lenses.
Dyslexia: the link with visual deficits
Authors: Evans Bruce J. W. , Drasdo Neville , Richards Ian L.
Published: July 2002

Some research reports suggest that visual anomalies may have a causative role in dyslexia, and on this basis certain forms of therapy have been proposed. Recently, we have published the initial results of a matched group study which found dyslexia to be associated with binocular instability, reduced amplitude of accommodation, and reduced contrast sensitivity for both low spatial frequencies and uniform field flicker. The binocular instability was best identified by measuring the vergence amplitude: a modified Dunlop test failed to differentiate reliably between the two groups. Here, we report a significant correlation between flicker threshold and binocular instability, thus linking sensory and motor visual correlates of dyslexia. We also present further new analyses on the interaction between optometric variables and the psychometric measurement of coding skills. The results of these analyses disagree with a recent claim that binocular vision anomalies might cause poor performance at coding tasks. Our studies indicate that visual characteristics are not the major aetiological factors in specific reading difficulty.
Visual evoked potentials in children with developmental coordination disorder
Authors: Mon‐Williams M. A. , Mackie R. T. , McCulloch D. L. , Pascal E.
Published: July 2002

Children who demonstrate problems with skilled movement in the absence of physical handicap are formally designated as suffering from developmental coordination disorder (DCD). Diagnosis of DCD was confirmed by the ‘movement assessment battery for children’. Visually evoked potentials (VEPs) were recorded to evaluate the integrity of the visual pathway and to rule out the presence of any neurological lesions affecting visual input. Binocular, pattern onset VEPs were recorded in 14 children with DCD aged between five and seven years, and an age‐matched control group using pattern onset, high contrast, grating stimuli. Implicit times to the first and second peaks and troughs were measured, and results between the two groups were compared. Inattention and movement artefact meant that VEPs were more difficult to record within the DCD group, resulting in smaller amplitudes of the waveform, but no significant differences in the implicit times were observed between the DCD group and controls. Further research is required to determine the specific source of the neurological deficits in DCD but a problem with the integrity of the afferent visual pathway does not appear to be a causal factor.
The exact solution for the centre thickness of spectacle and contact lenses
Authors: De Faria e Sousa Sidney J. , Ventura Liliane
Published: July 2002

The available methods for the exact calculation of centre thickness presuppose that one knows simultaneously both surfaces of the lens and that the lens' power is determined afterwards. However, this approach is of secondary importance in practical situations. The issue in daily practice is the determination of the centre thickness of lenses that already have explicit vertex powers. In such cases one can set only one surface. The other has to be calculated following the prescription, the known surface and the optical effect of the centre thickness. Exact solution for this problem leads to four expressions, reflecting the number of ways one can treat it. Two of them are complete second‐order algebraic equations and the other two, complete third‐order algebraic equations. The practical value of the latter is limited by the fact that one cannot always obtain their three roots by pure algebraic procedures.