Global, regional, and national consumption of animal-source foods between 1990 and 2018: findings from the Global Dietary Database

Background

Methods

Findings

Interpretation

Funding

Incorporating geography into a new generalized theoretical and statistical framework addressing the modifiable areal unit problem

Background

All analyses of spatially aggregated data are vulnerable to the modifiable areal unit problem (MAUP), which describes the sensitivity of analytical results to the arbitrary choice of spatial aggregation unit at which data are measured. The MAUP is a serious problem endemic to analyses of spatially aggregated data in all scientific disciplines. However, the impact of the MAUP is rarely considered, perhaps partly because it is still widely considered to be unsolvable.

Results

It was originally understood that a solution to the MAUP should constitute a comprehensive statistical framework describing the regularities in estimates of association observed at different combinations of spatial scale and zonation. Additionally, it has been debated how such a solution should incorporate the geographical characteristics of areal units (e.g. shape, size, and configuration), and in particular whether this can be achieved in a purely mathematical framework (i.e. independent of areal units). We argue that the consideration of areal units must form part of a solution to the MAUP, since the MAUP only manifests in their presence. Thus, we present a theoretical and statistical framework that incorporates the characteristics of areal units by combining estimates obtained from different scales and zonations. We show that associations estimated at scales larger than a minimal geographical unit of analysis are systematically biased from a true minimal-level effect, with different zonations generating uniquely biased estimates. Therefore, it is fundamentally erroneous to infer conclusions based on data that are spatially aggregated beyond the minimal level. Instead, researchers should measure and display information, estimate effects, and infer conclusions at the smallest possible meaningful geographical scale. The framework we develop facilitates this.

Conclusions

The proposed framework represents a new minimum standard in the estimation of associations using spatially aggregated data, and a reference point against which previous findings and misconceptions related to the MAUP can be understood.

Electronic supplementary material

The online version of this article (10.1186/s12942-019-0170-3) contains supplementary material, which is available to authorized users.

Prevalence of Dementia in People Aged 60 Years and Above: Results from the WiSE Study

BACKGROUND

The challenge of an aging population with its expected attendant problem of an increase in the number of people with dementia is a growing concern across the world.

OBJECTIVE

The aims of this study were to establish the prevalence and risk factors of dementia in Singapore among the elderly resident population (aged 60 years and above).

METHODS

The WiSE study was a comprehensive single phase, cross-sectional, epidemiological survey that adapted the 10/66 protocol to establish the 10/66 and the Diagnostic and Statistical Manual of mental disorders -fourth edition (DSM-IV) diagnosis of dementia. 10/66 and DSM-IV dementia diagnosis as established by the survey questionnaires was validated by comparing against a gold standard of clinical assessment.

RESULTS

A total of 2,565 respondents completed the study giving a response rate of 65.6%. The validity of 10/66 dementia was higher (sensitivity = 95.6%, specificity = 81.8%) than that of DSM-IV dementia (sensitivity = 75.6%, specificity = 88.6%) when compared against the clinical gold standard. The study found that the prevalence of 10/66 dementia was 10% in the older adult population while the prevalence of DSM-IV dementia was 4.6%. Older age (75 years and above); no formal education, or completed primary education (versus higher education); homemaker and retired status (versus employed); and a history of stroke were associated with a higher risk of 10/66 dementia.

CONCLUSION

The establishment of accurate data on the number of people with dementia is essential in the planning of services and initiatives.

Benefits of Using CD45RA and CD28 to Investigate CD8 Subsets in Kidney Transplant Recipients

The deleterious role of CD8 T cells in kidney graft outcome has regained interest over the years, and memory T cells are considered as one of the main hurdles to achieve transplantation success. Monitoring the CD8 immune response in transplant recipients involved a heterogeneous combination of markers, but the justification of their choice is rarely stated. Whereas the number of parameters is not an issue in phenotypic analysis, functional assays have to accommodate the cell number with the narrowing of the subset. The aim of the study was to investigate the similarities and differences of the subsets identified using three nomenclatures (CD45RA and CCR7/CD27/CD28) in kidney transplant recipients with stable graft function. We found that all three nomenclatures can identify naïve and effector memory (EM) rheumatoid arthritis T cell CD8 with similar features. Whereas CM CD8 could only be documented using CCR7 and CD45RA, the characteristics of EM CD8 will differ according to the nomenclature. We found that the use of the CD45RA and CD28 gives the benefit of examining two EM populations at early and late differentiation states. This systematic comparison provides a cohesive layout of the advantages of using these nomenclature strategies in kidney transplant recipients to guide the choice of their use.

Body mass index and risk of mental disorders in the general population: results from the Singapore Mental Health Study

OBJECTIVE

The aims of the current study were to elucidate the association between body mass index (BMI) and mental disorders and to examine whether these associations are moderated by socio-demographic correlates and comorbid physical disorders.

METHODS

The Singapore Mental Health Study (SMHS) surveyed adult Singapore residents (Singapore citizens and permanent residents) aged 18 years and above. The survey was conducted from December 2009 to December 2010. The diagnoses of mental disorders were established using the World Mental Health Composite International Diagnostic Interview version 3.0 (CIDI 3.0). BMI was calculated using height and weight which were self-reported by respondents. The Euro-Qol-5Dimensions (EQ-5D) was used to measure the health related quality of life (HRQoL) in the sample.

RESULTS

Six thousand and six hundred sixteen respondents completed the study (response rate of 75.9%) and constituted a representative sample of the adult resident population in Singapore. Being underweight was associated with both lifetime (adjusted odds ratio (OR): 2.3) and 12-month obsessive-compulsive disorder (adjusted OR: 4.4). Obesity was associated with 12-month alcohol dependence (adjusted OR: 8.4). There were no significant differences in the EQ-5D indices or the EQ-VAS scores among the four BMI groups in the population.

CONCLUSIONS

Our findings are somewhat unique and different from those reported in research from Western countries. There is a need for further cross-cultural research to explore and identify genetic, metabolic and cultural differences that underlie the interaction between obesity and mental illnesses.

The Singapore Mental Health Study: an overview of the methodology

The Singapore Mental Health Study (SMHS) is a population-based, cross-sectional, epidemiological study on the Singapore multi-ethnic adult population. This article provides an overview of the research design and methods used which took into consideration the unique characteristics of the country and its multi-ethnic population. A face-to-face household survey of Singapore residents aged 18 years and above was undertaken from 2009 to 2010. The nationally representative probability sample was derived using a disproportionate stratified sampling method. In order to increase precision for subgroup estimations the design was stratified with over-sampling of Malays, Indians and those aged 65 years and above. Respondents were assessed using the English, Chinese (computerized) and Malay (paper and pencil based) version of the Composite International Diagnostic Interview (CIDI) 3.0 to establish lifetime and 12-month prevalence of mental disorders, the current use of mental health services (both Western and traditional services), the treatment gaps and loss of role functioning.

A Population-based Survey of Mental Disorders in Singapore

Introduction: Mental illnesses are not only a growing public health concern but also a major social and economic issue affecting individuals and families throughout the world. The prevalence of mental disorders, the extent of disability caused by these disorders, and services utilisation of these patients has been well studied in developed countries. The aim of this study was to establish the prevalence of select mental disorders and their associated sociodemographic correlates in the adult Singapore resident population. Materials and Methods: This was a cross-sectional, population-based, epidemiological study of adult Singapore residents aged 18 years and above. The subjects were randomly selected using a disproportionate stratified sampling method. The diagnoses of selected mental disorders including major depressive disorder (MDD), dysthymia, bipolar (bipolar I & II) disorders, generalised anxiety disorder (GAD), obsessive compulsive disorder (OCD), alcohol abuse and alcohol dependence were established using the Composite International Diagnostic Interview, which is a fully structured diagnostic instrument that assesses lifetime and 12-month prevalence of mental disorders. Results: Among the 6616 respondents (response rate of 75.9%), 12.0% had at least one lifetime affective, anxiety, or alcohol use disorders. The lifetime prevalence of MDD was 5.8% and that of bipolar disorder was 1.2%. The combined lifetime prevalence of the 2 anxiety disorders, GAD and OCD was 3.6%, with the latter being more common than GAD (0.9% and 3.0% respectively). The lifetime prevalence of alcohol abuse and dependence were found to be 3.1% and 0.5% respectively. Age, gender, ethnicity, marital status and chronic physical illnesses were all significant correlates of mental disorders. Conclusion: The identified associated factors would help guide resource allocation, policy formulation and programme development in Singapore. Key words: Affective disorders, Alcohol, Anxiety disorders, Population-based survey

A population-based survey of mental disorders in Singapore

INTRODUCTION

Mental illnesses are not only a growing public health concern but also a major social and economic issue affecting individuals and families throughout the world. The prevalence of mental disorders, the extent of disability caused by these disorders, and services utilisation of these patients has been well studied in developed countries. The aim of this study was to establish the prevalence of select mental disorders and their associated sociodemographic correlates in the adult Singapore resident population.

MATERIALS AND METHODS

This was a cross-sectional, populationbased, epidemiological study of adult Singapore residents aged 18 years and above. The subjects were randomly selected using a disproportionate stratified sampling method. The diagnoses of selected mental disorders including major depressive disorder (MDD), dysthymia, bipolar (bipolar I & II) disorders, generalised anxiety disorder (GAD), obsessive compulsive disorder (OCD), alcohol abuse and alcohol dependence were established using the Composite International Diagnostic Interview, which is a fully structured diagnostic instrument that assesses lifetime and 12-month prevalence of mental disorders.

RESULTS

Among the 6616 respondents (response rate of 75.9%), 12.0% had at least one lifetime affective, anxiety, or alcohol use disorders. The lifetime prevalence of MDD was 5.8% and that of bipolar disorder was 1.2%. The combined lifetime prevalence of the 2 anxiety disorders, GAD and OCD was 3.6%, with the latter being more common than GAD (0.9% and 3.0% respectively). The lifetime prevalence of alcohol abuse and dependence were found to be 3.1% and 0.5% respectively. Age, gender, ethnicity, marital status and chronic physical illnesses were all significant correlates of mental disorders.

CONCLUSION

The identified associated factors would help guide resource allocation, policy formulation and programme development in Singapore.

Microbial contamination of contact lenses and lens care accessories of soft contact lens wearers (university students) in Hong Kong

PURPOSE

This study aimed to examine the rates of microbial contamination, and identify contaminants associated with contact lenses and lens care accessories used by a group of young contact lens wearers.

METHODS

Collected contact lenses, lens cases, and lens care solutions were studied by bacterial culture. Contamination rates of these samples were recorded and compared with those reported in previous studies.

RESULTS

Of the samples tested, 9% of lens extracts, 34% of case extracts and 11% of solution samples were contaminated with ocular pathogenic microorganisms. Serratia spp., Staphylococcus aureus and coagulase-negative staphylococci were the most common microorganisms isolated. Lens cases were the most frequently contaminated item. Lens cases also yielded the widest range of bacterial isolates. Contact lenses used by occasional wearers were associated with a higher contamination rate. Using either saline or multipurpose solution to rinse lenses before use appeared to be effective in reducing incidence of contamination.

CONCLUSION

Our findings demonstrate that contact lenses and lens care accessories are not well maintained by contact lens wearers. Regular reviews and reinforcement of lens care procedures for the usage and care of contact lenses and lens care accessories is therefore important and essential.

Impact of working status on breastfeeding in Singapore: evidence from the National Breastfeeding Survey 2001

BACKGROUND

This study uses data from the 2001 Singapore National Breastfeeding Survey to examine factors, including working status, associated with breastfeeding duration.

METHODS

All women who delivered in the eight hospitals with obstetric services in Singapore from 1 April to 31 May 2001 were invited to participate in a survey on infant feeding and nutrition at 2 and 6 months postpartum. A total of 2149 respondents were interviewed for variables that were known or suspected to be associated with breastfeeding initiation and duration. Cox proportional hazards model was used to determine the associated effect of working status on breastfeeding duration. Kaplan-Meier estimate and survival curves were compared between working and non-working mothers.

RESULTS

Working status had no effect on initiation of breastfeeding, but had an effect on breastfeeding duration. The median breastfeeding duration for non-working and working mothers was 9 weeks and 8 weeks, respectively. This difference was significant by log rank test [hazard ratio (HR) = 1.27, 95% confidence interval (CI) 1.14-1.41, P value <0.001]. About 31% of non-working mothers breastfed for up to 6 months as compared to 20% of working mothers. Working mothers were more likely to stop breastfeeding than non-working mothers (HR = 1.61, 95% CI 1.43-1.85, P value = 0.001) after adjusting for potential confounders. The most important reason for working mothers stopping breastfeeding between 2 and 6 months was attributable to work.

CONCLUSION

More breastfeeding-friendly initiatives need to be put in place at workplaces to encourage working mothers to continue breastfeeding upon returning to work.

Aging and mfERG topography

AIM

To study the effect of aging retina on the multifocal electroretinogram (mfERG).

METHODS

A total of 18 young subjects (age 18-24 years) and 36 elderly subjects (aged 60-85 years) with intraocular lenses (IOLs) were recruited for this study. No subjects had significant eye diseases or media opacities. mfERG was measured in standard conditions using the VERIS system (version 4.1). There were three groups of 18 subjects: (1) 18-25 years, (2) 60-70 years, and (3) 75-85 years. mfERG responses were grouped into central, paracentral, and peripheral regions for analysis. The N1 amplitude, P1 amplitude, N1 latency, and P1 latency of the first-order responses were analysed.

RESULTS

Age had no effect on P1 latency, N1 amplitude, and P1 amplitude; however, N1 latencies from central to peripheral regions were significantly longer for group 3 than for group 1.

CONCLUSIONS

This study suggests that measured age-related decreases in mfERG responses are due to optical factors (decrease in retinal light levels, scatter) before the age of 70 years, but neural factors significantly affect mfERG topography after the age of 70 years.

Screening for myopia and refractive errors using LogMAR visual acuity by optometrists and a simplified visual acuity chart by nurses

PURPOSE

To compare the sensitivity and specificity of a widespread method of screening for refractive errors in Singapore schoolchildren using a simplified acuity screening chart with a more rigorous method using the Early Treatment Diabetic Retinopathy Study (ETDRS) chart. A secondary aim is to estimate the best cutoff values for the detection of refractive errors using these two methods.

METHODS

This is a population-based study, involving 1779 schoolchildren from three schools in Singapore. Logarithm of the minimum angle of resolution (logMAR) visual acuity was recorded using a modified Bailey-Lovie chart by trained optometrists, and visual acuity measurement was also undertaken using a simplified 7-line visual acuity screening chart by school health nurses. The main outcome measures were the receiver-operating characteristics (ROC's) of logMAR and the simplified screening visual acuity to detect myopia or any refractive errors. The difference between measurements, simplified screening visual acuity--logMAR visual acuity, was calculated.

RESULTS

The optimal threshold using the simplified screening visual acuity chart for the detection of myopia or any refractive error was 6/12 or worse. Using logMAR visual acuity, the most efficient threshold for the detection of myopia was 0.26, but this was 0.18 for the detection of any refractive error. The area under the ROC curves was significantly greater in the case of the logMAR visual acuity measurement compared with the simplified screening visual acuity measurement for the detection of myopia or any refractive errors. The 95% limits of agreement for the two methods (simplified screening--logMAR acuity) was -0.219 to +0.339.

CONCLUSIONS

Bearing in mind that the visual acuity measurements were performed by two different groups of professionals, visual acuity screening using the ETDRS method appears to be more accurate than the simplified charts for the detection of myopia or any refractive errors in children.

Effects of different degrees of cataract on the multifocal electroretinogram

AIM

To study the effect of different degrees of nuclear cataract on the multifocal electroretinogram (mfERG).

METHODS

mfERGs were recorded from 30 elderly subjects with very mild, mild, or moderate nuclear cataracts using a VERIS System (version 4.1). The subjects were divided into three groups (10 in each group) according to their degree of nuclear cataracts as classified according to the Lens Opacities Classification System III (LOCS III). No subjects had any significant eye disease or degenerative changes except for cataracts. The mfERG responses were grouped into six concentric rings for analysis. Both the N1 and P1 amplitudes and the latencies of N1 and P1 of first-order responses were used for analysis.

RESULTS

Amplitudes of N1 and P1 from the central retina (14 degrees) were significantly reduced in patients with mild or moderate cataract when compared with subjects with very mild cataract. However, there was no significant reduction of N1 and P1 amplitudes in the para-central retina (14-40 degrees). There was no difference in the latencies of N1 and P1 in these three groups of subjects.

CONCLUSIONS

The mfERG responses from the central retina (central 14 degrees) were affected by the severity of cataract, but responses from the paracentral retina (14-40 degrees) were not affected. This suggests that in interpreting the mfERG in subjects with mild or moderate cataract subjects some care should be taken as reduced amplitudes (N1 and P1) will be expected from the central retina.

Myopia in Singapore kindergarten children

PURPOSE

The purpose of this study was to examine whether close-up work was related to myopia in Singapore kindergarten children.

METHODS

One hundred twenty-eight children, ages 3 to 7 years, from a kindergarten in Singapore were examined by cycloplegic autorefraction. The parents also completed a questionnaire on the different types of close-up work activities each child was engaged in, socioeconomic status, and parental history of myopia.

RESULTS

Myopic children spent 3.0 hours per day (median) on close-up work activity, while nonmyopic children spent 2.0 hours per day (median) on close-up work activity. The prevalence of myopia in the sample was 8.6%.

CONCLUSION

Close-up work activity was not related to myopia in pre-school children.

The assessment of obesity: methods for measuring body fat and global prevalence of obesity

Fat is a normal component of the human body that is stored in adipose tissue. Obesity can be defined as a condition of excessive fat accumulation to the extent that health and well-being are affected. Body fat can be determined in vivo in different ways, using rather accurate laboratory techniques or using simple estimation techniques that can also be applied in field conditions. For population studies, the World Health Organization defines cut-off values for obesity based on the body mass index (BMI): weight/height squared (kg/m2). Generally, for adults, if the BMI exceeds 25 kg/m2, a subject is considered to be overweight, and if the BMI exceeds the value of 30 kg/m2, a subject is considered obese. However, the relationship between body fat percentage and BMI differs between ethnic groups, and, as a consequence, cut-off points for overweight and obesity based on BMI will have to be ethnicity specific. This means that, in some populations, the cut-off points could be lower or higher than the recommended figures. Adapting cut-off point values will have important consequences for prevalence data in some countries as the prevalence of obesity will dramatically increase or decrease. The prevalence of obesity, in children as well as in adults, is high in many countries all over the world and is rising. Given the impact of obesity on health, this is a public health issue that needs to be addressed seriously.

Body mass index and percent body fat: a meta analysis among different ethnic groups

OBJECTIVE

To study the relationship between percent body fat and body mass index (BMI) in different ethnic groups and to evaluate the validity of the BMI cut-off points for obesity.

DESIGN

Meta analysis of literature data.

SUBJECTS

Populations of American Blacks, Caucasians, Chinese, Ethiopians, Indonesians, Polynesians and Thais.

MEASUREMENTS

Mean values of BMI, percent body fat, gender and age were adapted from original papers.

RESULTS

The relationship between percent body fat and BMI differs in the ethnic groups studied. For the same level of body fat, age and gender, American Blacks have a 1.3 kg/m2 and Polynesians a 4.5 kg/m2 lower BMI compared to Caucasians. By contrast, in Chinese, Ethiopians, Indonesians and Thais BMIs are 1.9, 4.6, 3.2 and 2.9 kg/m2 lower compared to Caucasians, respectively. Slight differences in the relationship between percent body fat and BMI of American Caucasians and European Caucasians were also found. The differences found in the body fat/BMI relationship in different ethnic groups could be due to differences in energy balance as well as to differences in body build.

CONCLUSIONS

The results show that the relationship between percent body fat and BMI is different among different ethnic groups. This should have public health implications for the definitions of BMI cut-off points for obesity, which would need to be population-specific.

Reduction in stereoacuity with age and reduced retinal illuminance

Stereoacuity has been reported to decrease significantly in the seventh decade of life. Could this decrease be due to a reduction of retinal illuminance in the ageing eye? In this study, we used a more rigorous psychophysical procedure than that used previously, on 35 subjects, aged 21-67 years, to determine if the reported effect of age on stereoacuity could be replicated. We also compared the stereoacuity of 15 healthy young adults under normal and reduced retinal illuminance. A forced-choice algorithm was used to improve the accuracy of measurements. Results suggest that the reduced retinal illuminance resulting from normal ageing is not the cause of the decreased stereoacuity found with ageing.

PEG-coated lipid vesicles with encapsulated technetium-99m as blood pool agents for nuclear medicine

Unilamellar lipid vesicles of average diameter 200 nm containing 30 mM glutathione were internally labeled with 99mTc using exametazime (HMPAO) to transport technetium across the lipid bilayer. Vesicles were prepared both in the absence and presence of the lipid-polymer conjugate phosphatidylethanolamine-monomethoxy polyethylene glycol 5000 (PE-MPEG). Labeling efficiency both in the absence and presence of surface polymer was greater than 95% and the vesicles retained greater than 95% of their contents when incubated against 50% human serum at 37 degrees C for 12 h. When introduced intravenously into rabbits at a total lipid concentration of 4 mumol/kg (3.5 mg/kg), radiolabeled vesicles without surface polymer were rapidly cleared from the circulation with a half-life of approx. 30 min and delivered to liver and spleen, however if the lipid vesicles were prepared containing 3 or 4.5 mol percent PE-MPEG the circulation half-life of the label was approx. 5 and 10 h, respectively, and RES uptake was suppressed. These studies confirm a previous report of the utility of exametazime for preparing 99mTc-labeled lipid vesicles and demonstrate that extended circulation half-lives are achievable for 99mTc-labeled vesicles without recourse to high lipid doses and reticuloendothelial blockade. Applications to use exametazime as a blood pool marker in nuclear medicine are discussed.

Enhanced IgG production in eRDF media with and without serum. A comparative study

The performance of three basal media RPMI, DMEM/F12 (DF) and eRDF (enhanced RDF, RPMI:DMEM:F12 in 2:1:1) were evaluated in cultures with and without serum with respect to cell proliferation, metabolism and monoclonal antibody (Mab) productivity. Based on the ease of adaptation, growth rate, maximum cell density and Mab production, the media were ranked as follows: eRDF > DF > RPMI. This was true for serum-free (SF) and serum supplemented (SS) media in static and shaker cultures. Growth performances in static and shaker cultures were consistently 20-50% lower in all three SF media compared to the corresponding SS conditions. Antibody titres in DF/SF and RPMI/SF cultures, irrespective of the culture condition, were generally similar or slightly lower than their SS counterparts. However, eRDF/SF medium yielded a much higher Mab titre (193 mg l-1) compared to eRDF/SS medium (145 mg l-1). This was also six times higher than the lowest titre of 30 mg l-1 in RPMI/SF medium. Hybridomas in eRDF/SF were further adapted to media without bovine serum albumin (eRDF/SF-BSA). Maximum cell densities in these cultures improved with scale up, from 1.1 x 10(6) ml-1 in static, to 1.9 x 10(6) ml-1 in shaker flasks, to 2.5 x 10(6) ml-1 in bioreactors. However, Ig levels remained between 100-130 mg l-1 which were much lower than in eRDF/SF medium. Thus BSA appears to be necessary for Ig production. The manufacturing cost (excluding purification) of Ig using eRDF was calculated to be between 17-50% of the price of the other two media and therefore this is regarded as the best medium for Ig production.

Glycosylation and high-level secretion of human tumour necrosis factor-beta in recombinant baculovirus-infected insect cells

Human tumour necrosis factor-beta (TNF-beta) was produced in eukaryotic cells using the insect baculovirus cloning and expression system. A novel insect signal sequence, the honey-bee (Apis mellifera) prepromelittin secretory sequence, was used to aid in the post-translational modifications, glycosylation and secretion of recombinant human TNF-beta. Human TNF-beta cDNA was cloned using the insect baculovirus vector pAcC4s. Expression of the human TNF-beta was regulated by the insect Autographa californica nuclear-polyhedrosis-virus polyhedrin promoter. The 5' end of the TNF-beta cDNA was fused to the honey-bee prepromelittin signal sequence on the baculovirus vector. Insect [Spodoptera frugiperda (Sf9)] cells infected with the recombinant baculovirus secreted high levels of recombinant human TNF-beta into the culture medium. The amount of TNF-beta secreted by the Sf9 cells was estimated to be 28 micrograms of TNF-beta/ml of culture medium at 60-72 h post infection. The secreted human TNF-beta was a 22.5 kDa polypeptide which was glycosylated. Amino acid sequencing of the N-terminus of the recombinant human TNF-beta purified from the infected Sf9-cell culture confirmed that the secreted product was indeed human TNF-beta. This demonstrates that the honey-bee prepromelittin signal sequence was efficiently recognized and accurately cleaved in the Sf9 insect cells. The insect-derived TNF-beta exhibited a high cytotoxic activity similar to that of the native human TNF-beta when assessed by cytotoxic assays using murine L929 cells. Thus the insect baculovirus expression vector can be used for the production of abundant quantities of biologically active, glycosylated human TNF-beta protein.

Age, gender, and tear break-up time

We investigated the effect of age and gender on the tear break-up time (TBUT) of 2 groups of normal, asymptomatic subjects [92 Hong Kong-Chinese (HK-Chinese) and 76 Singapore-Chinese (S-Chinese)] using the conventional fluorescein-instillation technique. The mean TBUT (+/- SD) is 6.5 (+/- 4.0) s for the S-Chinese and 7.8 (+/- 2.4) s for the HK-Chinese. The mode was 7.0 s for HK-Chinese and 5.0 s for S-Chinese. About 80% of the subjects of each group have TBUT less than 10 s. The TBUT of both groups of Chinese decreases with age. It was found that TBUT was significantly different between the two sexes in the S-Chinese but no equivalent effect was observed in the HK-Chinese.

Role of heredity in the genesis of myopia

Previous studies suggest that myopia in parents may influence the genesis of myopia in their offspring. In this study, we surveyed 2888 children of Chinese descent in China and Hong Kong to determine the relationship between the refractive state of parents and their children. The age range of the children was 7-17 years. Refraction was measured using a Canon R-22 objective infrared autorefractor and a survey on family history of ametropia was conducted using a questionnaire. We found that children with myopic parents are more likely to be myopic.

Breakfast practices in the Asian region

Studies on changing dietary patterns throughout the Asian region have focused largely on overall alterations in nutrient intakes and changes in the consumption of various food groups. Changes in individual meal patterns have received little attention. Although country and regional differences occur, the first meal of the day, breakfast, tends to take the form of a traditional meal in most south-east Asian countries. Grain and cereal products, such as rice and wheat and rice noodles, appear to be dietary staples at breakfast In some countries, the more traditional grain products are being replaced by alternative cereals, such as bread. Lifestyle changes and accompanying urbanization together with rising affluence, appear to be largely responsible for dietary alterations. The health implications of these changes require further investigation.

Schirmer test. I. A review

Since its introduction by Schirmer in 1903, the Schirmer test has been widely used for the assessment of the adequacy of tear production. Although the faults of the Schirmer test have been well documented, it is nevertheless still being used to assess tear production, especially in the diagnosis of keratoconjunctivitis sicca (KCS) and for screening potential contact lens wearers. We summarize the findings and conclusions of some of the previous studies.

Schirmer test. II. A clinical study of its repeatability

In most parts of the world, the Schirmer test (ST) is still the main test used by optometrists for the assessment of tear adequacy in the screening of potential contact lens wearers and as an aid in the diagnosis of "dry" eye. We tested the reliability of a 1-min ST in nine normal Hong Kong-Chinese (HK-Chinese) subjects during five to seven visits over a period of 2 weeks. For 4 of the subjects, the test consistently measured 0 mm/1 min, and 68% of the test results were less than 6 mm/1 min, a value suggested as the lower limit for normal asymptomatic eyes. The results obtained were inconsistent and it is concluded that the ST is unreliable and of little clinical value in this population.

Studies on the chronopharmacology of ethanol

Male subjects (n = 10) were given ethanol (0.75 g/kg) at four equally spaced times in the 24 hr cycle (9 am, 3 pm, 9 pm 3 am) in random order. Blood ethanol concentrations were monitored by breath analysis and measurements were made of the blood or plasma levels of ethanol, acetaldehyde, acetate, pyruvate, lactate and cortisol. Blood pressure, heart rate and body temperature were measured before and at 60 and 120 min after ethanol administration and the effects of ethanol on a number of behavioural parameters and mood were studied. After ethanol ingestion, there was a significant decrease in body temperature, systolic blood pressure, plasma cortisol and pyruvate levels, whilst acetate levels and the lactate:pyruvate ratio were significantly increased. Standing steadiness, critical flicker fusion threshold and divided attention tracking control were significantly impaired under ethanol and self-report data indicated a significant decrease in alertness, co-ordination, concentration and attentiveness. Although a significantly higher peak blood ethanol concentration was attained at the 9 am session, other time-of-day differences did not reach significance and the pharmacokinetics of ethanol were essentially unchanged. Since the only significant diurnal variations in the response to ethanol identified in this study (apart from the subjective results) were for plasma cortisol concentrations and body temperature (both of which are well known to exhibit diurnal rhythmicity), it appears that major circadian variability in the metabolic and/or behavioural effects of ethanol is unlikely to occur.

Crystalline lens power in myopia

Growth of the eye shows a coordinated pattern whereby the reduction in refractive power of the cornea and crystalline lens tends to reduce the myopia that would otherwise result from the normal increase in axial length. There is some controversy as to whether the reduction in crystalline lens power is influenced by the refractive state of the eye, i.e., an active role in the emmetropization process, or is simply related to the changing lens dimension occurring with growth. We measured ocular dimensions and determined the crystalline lens powers in 19 myopes and 19 emmetropic subjects matched for age, gender, and ethnic origin. No significant difference was found in corneal radius of curvature for the two groups, but there was a significant difference (p < 0.05) in crystalline lens power of 2.30 D. These results suggest that greater compensation for axial elongation of the eye was afforded by the decrease in crystalline lens power than by corneal flattening.

Reliability of the tear break-up time technique of assessing tear stability and the locations of the tear break-up in Hong Kong Chinese

The measurement of tear break-up time (TBUT) in assessing stability of the tear film is somewhat controversial, even though the technique is widely used. We examined reliability of the technique within and among examiners and conclude that measurements of TBUT can be made reliably; full-beam observation of the cornea is preferable to scanning the cornea with a narrow slit in making the measurements. There may be differences in TBUT measurements made in the same subjects among examiners, but these differences are smaller with more experienced practitioners. In the Hong Kong Chinese (HK-Chinese), tear break-up appears to be more likely to first occur in the inferior periphery of the cornea. In this population mean TBUT is about 7.20 s; assuming a Gaussian distribution of TBUT values, 2.1 s should be adopted as the lower limit for normal TBUT in HK-Chinese.

Tear break-up time is related to blink frequency

The relationship between tear break-up time and blink frequency was investigated in a group of 41 subjects. A significant relationship between tear break-up time and blinking was found. This suggests that tear stability plays an important role in stimulating normal involuntary blinking.

Binocular inhibition: psychophysical and electrophysiological evidence

Binocular summation, defined as an increase in the binocular response compared with the monocular, occurs when the sensitivities of the two eyes are equal. We investigated the psychophysical and electrophysiological binocular response to a difference in monocular retinal illuminance. Different levels of unequal monocular sensitivities were induced by means of neutral density filters placed in front of one eye. Both studies produced similar results. In the absence of filters, maximum binocular summation was produced. With increasing difference in monocular illuminance, the binocular response decreased steadily until it reached a level below the monocular. The clinical implications of binocular inhibition, a perceptual phenomenon similar to Fechner's Paradox, are discussed.

Do intraocular lenses with ultraviolet absorbing chromophores protect against macular oedema?

In a prospective study, designed to test the effect of intraocular lenses containing an ultraviolet absorbing chromophore on the incidence of post-operative cystoid macular oedema, 55 patients undergoing extracapsular cataract extraction were randomly allocated to receive intraocular lenses with or without an ultra-violet absorbing chromophore. Post-operative fluorescein angiography showed no difference in the incidence of macular oedema in those patients receiving an intraocular lens with an ultraviolet absorbing chromophore compared with patients receiving a standard posterior chamber intraocular lens.

Causes of blindness and partial sight in the Bradford Metropolitan District from 1980 to 1985

A retrospective review of the BD8 forms submitted for the period 1980-85 in the Bradford Metropolitan District was conducted to ascertain the incidence and causes of blindness and partial sight. A total of 1485 cases were registered in this period of which 755 (50%) were included in the Blind register and 730 (49.2%) in the Partially Sighted register. Age-related macular degeneration was the most important cause of visual handicap, accounting for 43.9% of all registrations, followed by glaucoma (16.2%), diabetic retinopathy (6.3%), myopic degeneration (6.1%), optic atrophy (4.4%), cerebrovascular disease (3.8%), cataracts (3.6%), retinal vascular occlusive disease (3.2%), corneal opacities (3.0%), congenital anomalies (2.7%), retinitis pigmentosa/tapeto-retinal degeneration (1.9%), retinal detachment (1.8%) and others (3.1%). The ratio of female to male registrations was 1.8:1. Eighty-four per cent of this sample population was above the age of 60 years at the time of registration.

Edge contrast sensitivity in optometric practice: an assessment of its efficacy in detecting visual dysfunction

The utility of the Melbourne Edge Test (MET) in optometric practice was evaluated by screening 293 consecutive patients who presented for routine eye examination. The MET identified ocular abnormalities in 37 eyes. Of these, 36 also manifested a reduction of visual acuity. The incidence of "false positives" was 1.0%. The MET test failed to detect ocular abnormalities revealed by conventional examination techniques in 29 eyes (4.9%), of which 28 exhibited Snellen acuity losses.

Contrast sensitivity and pattern ERG in Waldenstrom's macroglobulinaemia

Patients with Waldenstrom's macroglobulinaemia (WM) and age matched controls have been examined using tests of contrast sensitivity and pattern electroretinography. The patients with WM were in remission on maintenance treatment and had only moderately elevated plasma viscosity. They showed evidence of abnormal contrast sensitivity but there was no significant difference in amplitude of the pattern ERG between patients and controls.

Performance of amblyopic children on printed contrast sensitivity test charts

Forty consecutive amblyopic patients between the ages of 3 and 12 years attending the Orthoptic Clinic for assessment and treatment were tested on the AO Contrast Sensitivity System [Arden grating test (AGT)] and the VISTECH Contrast Sensitivity Charts. Recordings were unsuccessful in more than 50% of these patients on both test systems. Of those who could successfully complete the AGT, false negative results were noted in 62.5% of the amblyopic eyes and false positive results were found in 25% of the normal fellow eyes. On the near VISTECH chart, all normal and amblyopic eyes produced results that were outside the specified limit of normality. On the distance VISTECH chart, 25% of the normal fellow eyes gave false positive results and 25% of the amblyopic eyes gave false negative results. From these findings, it is doubtful whether either test system has a role in the routine clinical assessment of amblyopia.