Mental health in Ireland during the Covid pandemic: Evidence from two longitudinal surveys

BACKGROUND

The Covid pandemic arrived in Ireland on February 29, 2020. In the following weeks various restrictions were introduced to stem the spread of the disease. Anxiety over the spread of the disease and over the restrictions introduced had an adverse effect upon mental health. This study examines the change in mental health for two groups: young adults aged around 23 at the time of onset of Covid (the 1998 cohort) and a sample of principal carers (PCs) of children who were aged 13 at the onset of Covid (the 2008 cohort).

METHODS

Data were obtained from the two cohorts of the longitudinal Growing Up In Ireland (GUI) survey. The sample included 1953 young adults (from the 1998 cohort) and 3547 principal carers (from the 2008 cohort). Mental health as measured by the Centre for Epidemiological Studies Depression-8 scale was obtained for the last pre-Covid wave and for the Covid wave (surveyed in December 2020). Observations for which CES-D8 was not available in either pre or post Covid waves were excluded. Post-Covid sampling weights were applied. The change in depression rates was decomposed into a growth and distribution effect using a Shapley decomposition. The socioeconomic gradient of CES-D8 was examined pre and post Covid using concentration indices and a transition matrix was constructed to examine the dynamics of changes in CES-D8 and depression pre and post-Covid.

RESULTS

Relative to the last pre-Covid survey, mental health, as measured by CES-D8 deteriorated for both the young adults of the 1998 cohort and the PCs of the 2008 cohort. For young adults, the deterioration was more pronounced for females. There was no observable socioeconomic gradient for poor mental health amongst young adults, both pre and post Covid. For mothers from the 2008 cohort, a gradient was observed during the pre-COVID-19 pandemic period with poorer mental health status for lower-income and less educated mothers. This gradient was less pronounced post-Covid, the levelling-off arising from a greater deterioration in mental health for higher-income and better-educated PCs.

CONCLUSION

Both observed cohorts showed a significant deterioration in mental health post Covid. For young adults the effect was significantly more pronounced among females and this is consistent with generally poorer mental health amongst females in this age group. There was little or no socioeconomic gradient observed for young adults, but the gradient became more shallow for principal carers. Care must be taken in terms of drawing policy implications from this study as the Covid-19 pandemic was arguably a unique event, even allowing for the likelihood of future pandemics. However, the study highlights the vulnerability of young adults, especially females, to the mental health effects arising from major public health shocks.

Diamond-Like Carbon: A Surface for Extreme, High-Wear Environments

In this study, we present an in-depth characterization of a diamond-like carbon (DLC) film, using a range of techniques to understand the structure and chemistry of the film both in the interior and particularly at the DLC/air surface and DLC/liquid interface. The DLC film is found to be a combination of sp2 and sp3 carbon, with significant oxygen present at the surface. The oxygen seems to be present as OH groups, making the DLC somewhat hydrophilic. Quartz-Crystal Microbalance (QCM) isotherms and complementary neutron reflectivity data indicate significant adsorption of a model additive, bis(2-ethylhexyl) sulfosuccinate sodium salt (AOT) surfactant, onto the DLC from water solutions and indicate the adsorbed film is a bilayer. This initial study of the structure and composition of a model surfactant is intended to give a clearer insight into how DLC and additives function as antiwear systems.

How Reproducible are Surface Areas Calculated from the BET Equation?

Porosity and surface area analysis play a prominent role in modern materials science. At the heart of this sits the Brunauer-Emmett-Teller (BET) theory, which has been a remarkably successful contribution to the field of materials science. The BET method was developed in the 1930s for open surfaces but is now the most widely used metric for the estimation of surface areas of micro- and mesoporous materials. Despite its widespread use, the calculation of BET surface areas causes a spread in reported areas, resulting in reproducibility problems in both academia and industry. To prove this, for this analysis, 18 already-measured raw adsorption isotherms were provided to sixty-one labs, who were asked to calculate the corresponding BET areas. This round-robin exercise resulted in a wide range of values. Here, the reproducibility of BET area determination from identical isotherms is demonstrated to be a largely ignored issue, raising critical concerns over the reliability of reported BET areas. To solve this major issue, a new computational approach to accurately and systematically determine the BET area of nanoporous materials is developed. The software, called "BET surface identification" (BETSI), expands on the well-known Rouquerol criteria and makes an unambiguous BET area assignment possible.

From computational high-throughput screenings to the lab: taking metal–organic frameworks out of the computer

Computational high-throughput screenings (HTS) have become a standard method of sieving the vast amount of metal–organic frameworks (MOFs) data. But not many HTS studies have been able to bring MOFs to the lab.

Age-Related Macular Degeneration and the Aging Brain

Age-related macular degeneration (AMD), a leading cause of vision loss in older Americans, is associated with cognitive decline and, particularly, worse performance on verbal fluency tasks. To determine whether AMD is associated with changes in brain structure that may underlie decline in cognition, we conducted a longitudinal, observational study of 39 visually impaired AMD patients and 33 age-matched peers with healthy eyes. Participants (mean age 74.3) underwent cognitive assessments and 3T magnetic resonance imaging (MRI) at baseline and two years. At baseline, AMD patients exhibited lower cortical volume and worse white matter tract integrity, especially in inter-hemispheric connections (FDR <0.05). Principal components analyses revealed faster white matter decline in the AMD group, especially in visual cortex and left hemisphere, which is implicated in language tasks. Understanding patterns of regional brain atrophy in AMD sheds light on mechanisms for the AMD-cognition link and opens windows of opportunity for intervention.

Identifying Differing Intracellular Cargo Release Mechanisms by Monitoring In Vitro Drug Delivery from MOFs in Real Time

Metal-organic frameworks (MOFs) have been proposed as biocompatible candidates for the targeted intracellular delivery of chemotherapeutic payloads, but the site of drug loading and subsequent effect on intracellular release is often overlooked. Here, we analyze doxorubicin delivery to cancer cells by MIL-101(Cr) and UiO-66 in real time. Having experimentally and computationally verified that doxorubicin is pore loaded in MIL-101(Cr) and surface loaded on UiO-66, different time-dependent cytotoxicity profiles are observed by real-time cell analysis and confocal microscopy. The attenuated release of aggregated doxorubicin from the surface of Dox@UiO-66 results in a 12 to 16 h induction of cytotoxicity, while rapid release of pore-dispersed doxorubicin from Dox@MIL-101(Cr) leads to significantly higher intranuclear localization and rapid cell death. In verifying real-time cell analysis as a versatile tool to assess biocompatibility and drug delivery, we show that the localization of drugs in (or on) MOF nanoparticles controls delivery profiles and is key to understanding in vitro modes of action.

BMI mobility and obesity transitions among children in Ireland

This paper examines mobility and changes in Body Mass Index (BMI) for a sample of Irish children/adolescents across three waves of the longitudinal Growing Up in Ireland dataset. Particular attention is paid to transitions across the key BMI thresholds of overweight and obesity. Analysis is carried out by gender and by maternal education. In general, mobility is observed, with intra-generational rank-rank BMI coefficients of around 0.63 compared to coefficients of around 0.77 for the mothers of the children over the same time period. Across the distribution as a whole there is relatively little variation by gender and maternal education. However there a gender difference in terms of mobility out of obesity with the Shorrocks mobility index across categories of normal weight/overweight/obesity taking a value of 0.56 for females as opposed to 0.71 for males. This relative lack of mobility is more observed in later rather than earlier adolescence.

Psychological Distress and Zika, Dengue and Chikungunya Symptoms Following the 2016 Earthquake in Bahía de Caráquez, Ecuador

On 16 April 2016, a 7.8 magnitude earthquake struck coastal Ecuador, resulting in significant mortality and morbidity, damages to infrastructure, and psychological trauma. This event coincided with the first outbreak of Zika virus (ZIKV) and co-circulation with dengue virus (DENV) and chikungunya virus (CHIKV). We tested whether the degree of psychological distress was associated with the presence of suspected DENV, CHIKV, ZIKV (DCZ) infections three months after the earthquake. In July 2016, 601 household members from four communities in Bahía de Caráquez, Manabí Province, Ecuador, were surveyed in a post-disaster health evaluation. Information was collected on demographics, physical damages and injuries, chronic diseases, self-reported psychological distress, and DCZ symptoms. We calculated the prevalence of arbovirus and distress symptoms by community. ANOVA was used to compare the mean number of psychological distress symptoms between people with versus without suspected DCZ infections by age, gender, community and the need to sleep outside of the home due to damages. The prevalence of suspected DCZ infections was 9.7% and the prevalence of psychological distress was 58.1%. The average number of psychological distress symptoms was significantly higher among people with suspected DCZ infections in the periurban community of Bella Vista, in women, in adults 40-64 years of age and in individuals not sleeping at home (p < 0.05). The results of this study highlight the need to investigate the interactions between psychological distress and arboviral infections following natural disasters.

Childhood obesity and maternal education in Ireland

This paper analyses the socioeconomic gradient of childhood obesity in Ireland using the Growing Up in Ireland data with three innovations compared to previous work in the area. A different measure of socioeconomic status, maternal education, is employed. In addition, the depth and severity of obesity are examined as well as the incidence. Finally, the use of two waves of longitudinal data permits the analysis of the persistence of obesity. Results show that overall childhood obesity stabilised between the two waves. However the socioeconomic gradient becomes steeper in wave 2 for girls and in particular when depth, severity and persistence of obesity are accounted for. Girls whose mothers fail to complete secondary education are shown to be at a particular disadvantage.

The poverty effects of a 'fat-tax' in Ireland

To combat growing levels of obesity, health-related taxes have been suggested with taxes on foods high in fat or sugar. Such taxes have been criticised on the basis of their regressivity and potentially adverse impact upon poverty. This paper analyses the effect of such taxes on a range of poverty measures and also examines the effect of a revenue-neutral tax subsidy mixed with a tax on unhealthy food combined with a subsidy on more healthy food. Using Irish expenditure data, the results indicate that taxes on high fat/sugar goods on their own will be regressive but that a tax-subsidy combination can be broadly neutral with respect to poverty.

The potential impact on obesity of a 10% tax on sugar-sweetened beverages in Ireland, an effect assessment modelling study

BACKGROUND

Some governments have recently shown a willingness to introduce taxes on unhealthy foods and drinks. In 2011, the Irish Minister for Health proposed a 10% tax on sugar sweetened beverages (SSBs) as a measure to combat childhood obesity. Whilst this proposed tax received considerable support, the Irish Department of Finance requested a Health Impact Assessment of this measure. As part of this assessment we set out to model the impact on obesity.

METHODS

We used price elasticity estimates to calculate the effect of a 10% SSB tax on SSB consumption. SSBs were assumed to have an own-price elasticity of -0.9 and we assumed a tax pass-on rate to consumers of 90%. Baseline SSB consumption and obesity prevalence, by age, sex and income-group, for Ireland were taken from the 2007 Survey on Lifestyle and Attitude to Nutrition. A comparative risk assessment model was used to estimate the effect on obesity arising from the predicted change in calorie consumption, both for the whole population and for sub-groups (age, sex, income). Sensitivity analyses were conducted on price-elasticity estimates and tax pass-on rates.

RESULTS

We estimate that a 10% tax on SSBs will result in a mean reduction in energy intake of 2.1 kcal/person/day. After adjustment for self-reported data, the 10% tax is predicted to reduce the percentage of the obese adult population (body mass index [BMI] ≥ 30 kg/m(2)) by 1.3%, equating to 9,900 adults (95% credible intervals: 7,750 to 12,940), and the overweight or obese population (BMI ≥ 25 kg/m(2)) by 0.7%, or 14,380 adults (9,790 to 17,820). Reductions in obesity are similar for men (1.2%) and women (1.3%), and similar for each income group (between 1.1% and 1.4% across income groups). Reductions in obesity are greater in young adults than older adults (e.g. 2.9% in adults aged 18-24 years vs 0.6% in adults aged 65 years and over).

CONCLUSIONS

This study suggests that a tax on SSBs in Ireland would have a small but meaningful effect on obesity. While such a tax would be perceived as affecting the whole population, from a health prospective the tax will predominantly affect younger adults who are the main consumers of SSBs.

Adjusting the obesity thresholds for self-reported BMI in Ireland: a cross-sectional analysis

OBJECTIVE

To investigate the optimal adjustment to be made to obesity thresholds when using self-reported body mass index (BMI).

DESIGN

A cross-sectional study.

SETTING

Data from the Survey of Lifestyle, Attitudes and Nutrition in Ireland, a nationally representative dataset using the Geodirectory (a listing of all residential addresses in Ireland compiled by the postal service) as the sampling frame.

PARTICIPANTS

A nationally representative sample of 10 364 adults aged 18+, carried out by face-to-face interview with clinical measurement applied to a number of outcomes to a representative subsample of 2174. After discarding the observations with missing values and errors, the eventual sample was 1874.

PRIMARY AND SECONDARY OUTCOME MEASURES

BMI based on measured and self-reported weight and height.

BACKGROUND

It is generally found that self-reported BMI understates true or measured BMI and accordingly revised obesity thresholds have been suggested.

METHODS

Data from the 2007 Survey of Lifestyles, Attitudes and Nutrition in Ireland were used to analyse self-reported and measured BMI. The self-reported BMI threshold was adjusted to obtain the optimal signal for measured BMI using different criteria viz. efficiency (maximum number of correct classifications), maximisation of Youden's J, maximisation of OR, minimisation of cost of misclassification and constrained optimisation.

RESULTS

The optimal threshold differed substantially depending on the criterion adopted for choosing it, with thresholds of 29.1 (efficiency criterion), 27.5 (Youden's J) and 26.0 (FN rate of 5%). Standard criteria such as Youden's J index were shown to implicitly impose relative costs of false-negatives and false-positives which may not always correspond to the values of the analyst.

CONCLUSIONS

When adjusting self-reported BMI thresholds in order to obtain the optimal signal for 'true' obesity, analysts should explicitly choose the relative costs of false-positives and false-negatives.

Opinions of children about participation in medical genetic research

AIMS

The objective was to evaluate children's opinions about their participation in a large research project.

METHODS

Polish children between 6 and 14 years of age completed a questionnaire about their participation in the Polish Gabriel study (which aims to identify genetic and environmental causes of asthma). In total 706 questionnaires were collected.

RESULTS

Children's main motivation for participation was wanting to know whether they were healthy or not. Most children could think of no reasons to reconsider participation. Children aged 6-10 years might reconsider participating because they did not know what was going to happen. A third of the children were not informed by anybody about the study. Especially the youngest children indicated a need for a tailored letter (42%). The youngest children were less often asked for their opinion about participation. All children preferred that both parents and children are asked for consent or assent. Children who were not informed or not asked for their opinion seemed less emotionally involved in the study.

CONCLUSION

While researchers and parents tend to focus their information provision to older children and include them in decision-making, especially the younger children expressed a need for more tailored information and involvement in their participation in research.

Ordinal and cardinal measures of health inequality: an empirical comparison

When measuring health inequality using ordinal data, analysts typically must choose between indices specifically based upon ordinal data and more standard indices using ordinal data, which has been transformed into cardinal data. This paper compares inequality rankings across a number of different approaches and finds considerable sensitivity to the choice between ordinal- and cardinal-based indices. There is relatively little sensitivity to the ethical choices made by the analyst in terms of the weight attached to different parts of the distribution.

Mental stress in Ireland, 1994-2000: a stochastic dominance approach

The General Health Questionnaire (GHQ) is frequently used as a measure of mental well-being with those people with values below a certain threshold regarded as suffering from mental stress. Comparison of mental stress levels across populations may then be sensitive to the chosen threshold. This paper uses stochastic dominance techniques to show that mental stress fell in Ireland over the 1994-2000 period regardless of the threshold chosen. Decomposition techniques suggest that changes in the proportion unemployed and in the protective effect of income, education and marital status upon mental health were the principal factors underlying this fall.

Sample selection versus two-part models revisited: the case of female smoking and drinking

There is a well-established debate between Heckman sample selection and two-part models in health econometrics, particularly when no obvious exclusion restrictions are available. Most of this debate has focussed on the application of these models to health care expenditure. This paper revisits the debate in the context of female smoking and drinking, and evaluates the two approaches on three grounds: theoretical, practical and statistical. The two-part model is generally favoured but it is stressed that this comparison should be carried out on a case-by-case basis.

GP reimbursement and visiting behaviour in Ireland

In Ireland, approximately 30% of the population receive free GP services (medical card patients) while the remainder (private patients) must pay for each visit. In 1989, the manner in which GPs were reimbursed by the State for their medical card patients was changed from fee-for-service to capitation while private patients continued to pay on a fee-for-service basis. Concerns about supplier-induced demand were in part responsible for this policy change. The purpose of this paper is to examine the extent to which the utilisation of GP services is influenced by the reimbursement system facing GPs, by comparing visiting rates for the two groups before and after this change. Using a difference-in-differences approach on pooled micro-data from 1987, 1995 and 2000, we find that medical card eligibility has a consistently positive and significant effect on the utilisation of GP services. However, the differential in visiting rates between medical card patients and others did not narrow between 1987 and 1995 or 2000, as might have been anticipated if supplier-induced demand played a major role prior to the change in reimbursement system.

The use of lamotrigine, vigabatrin and gabapentin as add-on therapy in intractable epilepsy of childhood

PURPOSE

Lamotrigine (LTG), vigabatrin (VGB) and gabapentin (GBP) are three anti-epileptic drugs (AEDs) used in the treatment of children with epilepsy for which long-term retention rates are not currently well known. This study examines the efficacy, long-term survival and adverse event profile of these three agents used as add-on therapy in children with refractory epilepsy over a 10-year period.

METHODS

Three separate audits were conducted between February 1996 and September 2000. All children studied had epilepsy refractory to other AEDs. Efficacy was confirmed if a patient became seizure free or achieved >50% reduction in seizure frequency for 6 months or more after starting therapy. Adverse events and patient survival for each drug were recorded at the end of the study period.

RESULTS

Between September 1990 and February 1996, 132 children received LTG, 80 VGB and 39 GBP. At the 10-year follow-up audit, 33% of the children on LTG had a sustained beneficial effect on their seizure frequency in contrast to 19% for VGB and 15% for GBP. No significant difference in efficacy was found in children with partial seizures. Children with epileptic encephalopathy (EE) including myoclonic-astatic epilepsy and Lennox-Gastaut Syndrome (LGS) achieved a more favorable response to LTG. The main reasons for drug withdrawal were lack of efficacy for VGB, apparent worsening of seizures for GBP and the development of a rash for LTG.

CONCLUSIONS

Lamotrigine is a useful add-on therapy in treating children with epilepsy. It has a low adverse event profile and a sustained beneficial effect in children with intractable epilepsy.

Placental fetal thrombotic vasculopathy is associated with neonatal encephalopathy*1

Neonatal encephalopathy (NE) remains an important cause of morbidity and mortality in the term infant, and many cases have an antepartum, rather than an intrapartum, etiology. Chronic processes such as thrombosis result in changes in the placenta. We sought to determine whether histopathological examination of the placenta in cases of NE, focusing on these changes, could identify significant antenatal processes that are not recognized by clinical assessment alone. Infants born at term with NE were identified retrospectively over a 12-year period. Placental tissue from deliveries during the study period was available for reexamination. Controls were selected from a cohort of 1000 consecutive deliveries on which clinical and pathological data were collected as part of an earlier study. Bivariate and multivariate analyses of clinical and pathological factors for cases and controls were used to test for an independent association with NE. Clinical and placental data was collected on 93 cases of NE and 387 controls. The placental features of fetal thrombotic vasculopathy (FTV), funisitis (signifying a fetal response to infection), and accelerated villous maturation were independently associated with NE. Of the clinical factors studied, meconium-stained liquor and abnormal cardiotocograph were independently associated. There were no independently associated clinical antenatal factors. Placental features of infection, thrombosis, and disturbed uteroplacental flow are significant independent factors in the etiology of NE in this study. Acute and chronic features suggest that NE may result from acute stress in an already compromised infant. The absence of significant clinical antenatal factors supports the value of placental examination in the investigation of infants with NE.

Dynamics of the COPII coat with GTP and stable analogues

We have developed an assay to monitor the assembly of the COPII coat onto liposomes in real time. We show that with Sar1pGTP bound to liposomes, a single round of assembly and disassembly of the COPII coat lasts a few seconds. The two large COPII complexes Sec23/24p and Sec13/31p bind almost instantaneously (in less than 1 s) to Sar1pGTP-doped liposomes. This binding is followed by a fast (less than 10 s) disassembly due to a 10-fold acceleration of the GTPase-activating protein activity of Sec23/24p by the Sec13/31p complex. Experiments with the phosphate analogue BeFx suggest that Sec23/24p provides residues directly involved in GTP hydrolysis on Sar1p.

First record and morphology of Myialges caulotoon (Acari: Epidermoptidae) from Galapagos hosts

Hippoboscid flies were collected from wild birds on Santiago and Fernandina Islands, Galapagos, Ecuador in August 1985. An epidermoptid mite, identified as Myialges caulotoon, was found on Icosta nigra from Galapagos Hawks and on Olfersia sordida from Brown Pelicans and a Flightless Cormorant. This report is the first record of Myialges from the 2 birds endemic to Galapagos. It is also the first report to provide an identity of a species of Myialges from Galapagos hosts.

Low altitude dose measurements from APEX, CRRES and DMSP

Dosimeter data taken on the APEX (1994-1996), CRRES (1990-1991) and DMSP (1984-1987) satellites have been used to study the low altitude (down to 350 km) radiation environment. Of special concern has been the inner edge of the inner radiation belt due to its steep gradient. We have constructed dose models of the inner edge of the belt from all three spacecraft and put them into a personal computer utility, called APEXRAD, that calculates dose for user-selected orbits. The variation of dose for low altitude, circular orbits is given as a function of altitude, inclination and particle type. Dose-depth curves show that shielding greater than approximately 1/4 in Al is largely ineffectual for low altitude orbits. The contribution of outer zone electrons to low altitude dose is shown to be important only for thin shields and to have significant variation with magnetic activity and solar cycle.

Identification of amino acids within the MHC molecule important for the interaction with the adenovirus protein E3/19K

The E3/19K protein of human adenovirus type 2 binds to class I MHC Ags thereby interfering with their cell surface expression and Ag presentation function. Currently, it is unclear exactly which structure of MHC molecules is recognized by the E3/19K protein. We have previously demonstrated that the murine H-2Kd Ag is able to associate with E3/19K, whereas the allelic H-2Kk molecule is not. By using exon shuffling between Kd and Kk molecules, the alpha 1 and alpha 2 domains of MHC class I molecules were identified as essential structures for binding the viral protein. In this report, we have examined the contribution of individual amino acids within the alpha 2 domain of MHC for binding E3/19K. First, we show that within this domain the alpha-helical part is most important for the interaction with E3/19K. By using site-directed mutagenesis, Kd-specific amino acids were introduced into the alpha-helix of the alpha 2 domain of Kk. By using the expression of mutagenized proteins in E3/19K+ cells, we have identified Tyr 156 and Leu 180 as being essential for the association with the E3/19K protein. In addition, Kd residue Glu 163 seems to contribute to the complex formation. Furthermore, analysis of a panel of Kd/Dd recombinants indicates that a similar region in the Dd molecule, namely, the C-terminal half of the alpha 2 domain, affects binding to E3/19K. Combining these results with Ab binding data, we present two alternative models of how the adenovirus protein may bind to the alpha 1 and alpha 2 domains.

Identification of amino acids within the MHC molecule important for the interaction with the adenovirus protein E3/19K

The E3/19K protein of human adenovirus type 2 binds to class I MHC Ags thereby interfering with their cell surface expression and Ag presentation function. Currently, it is unclear exactly which structure of MHC molecules is recognized by the E3/19K protein. We have previously demonstrated that the murine H-2Kd Ag is able to associate with E3/19K, whereas the allelic H-2Kk molecule is not. By using exon shuffling between Kd and Kk molecules, the alpha 1 and alpha 2 domains of MHC class I molecules were identified as essential structures for binding the viral protein. In this report, we have examined the contribution of individual amino acids within the alpha 2 domain of MHC for binding E3/19K. First, we show that within this domain the alpha-helical part is most important for the interaction with E3/19K. By using site-directed mutagenesis, Kd-specific amino acids were introduced into the alpha-helix of the alpha 2 domain of Kk. By using the expression of mutagenized proteins in E3/19K+ cells, we have identified Tyr 156 and Leu 180 as being essential for the association with the E3/19K protein. In addition, Kd residue Glu 163 seems to contribute to the complex formation. Furthermore, analysis of a panel of Kd/Dd recombinants indicates that a similar region in the Dd molecule, namely, the C-terminal half of the alpha 2 domain, affects binding to E3/19K. Combining these results with Ab binding data, we present two alternative models of how the adenovirus protein may bind to the alpha 1 and alpha 2 domains.

Genetic typing using automated electrophoresis and fluorescence detection

Multi-color fluorescence detection systems offer unique advantages when compared to single label detection methods for DNA typing, genetic disease testing, population fingerprinting, and DNA mapping. Internal controls are easily used and identified by different color dye labels. Multiple independent samples or multiple analyses of the same sample are run in each lane of a gel. Precision of size assignment and quantification are improved. Here, we will review a variety of methods used to analyze DNA and present the advantages of the multi-color fluorescence dye approach. An automated and quantitative DNA typing assay for human identification is shown. This method is an improvement over previous manual techniques and uses multi-color fluorescence labeling, electrophoresis and real-time detection methodology.

Tropical spastic paraparesis: clinical, immunological, and virological studies in two patients from Martinique

Two patients from Martinique with tropical spastic paraparesis had antibodies to human T-lymphotropic virus type I (HTLV-I) in serum and spinal fluid but no antibodies to other retroviruses tested. They presented with spastic weakness of both lower extremities, hyperreflexia with upgoing toes, sphincteric dysfunction, and normal sensation. By means of agarose isoelectric focusing and selective immunoblotting we demonstrated an increased intrathecal synthesis of IgG antibodies to HTLV-I in the spinal fluid. Unique oligoclonal bands of IgG antibodies to HTLV-I were present in the cerebrospinal fluid. Using a battery of monoclonal antibodies we also found in these patients an increased number of circulating T cells that expressed activation markers. We conclude that the HTLV-I retrovirus associated with tropical spastic paraparesis has both lymphocytotropic and neurotropic properties.

Effect of atrial natriuretic factor on acid-base homeostasis

Both micropuncture and clearance studies have shown that the anion excreted in the urine in response to the increased glomerular filtration rate and solute load induced by atrial natriuretic factor (ANF) depends on the pre-existing acid-base status. In normal animals, the kidney is relatively better at reabsorbing bicarbonate than chloride, as ANF increases luminal flow so that a chloruresis without bicarbonaturia ensues. In contrast, during chronic hypochloraemic metabolic alkalosis, alkalaemia renders the kidney unable to reabsorb the increment in filtered bicarbonate induced by ANF so that bicarbonaturia occurs with amelioration of the alkalosis. Since the relative magnitudes of chloride versus bicarbonate excretion rates in response to ANF are a function of the plasma anion concentrations, ANF tends to correct acid-base disorders.

Virus antibodies in the cerebrospinal fluid of multiple sclerosis patients detected with ELISA tests

The enzyme-linked immunosorbent assay (ELISA) was used to determine levels of specific IgG antibodies against measles, rubella, vaccinia, corona (OC43) and mumps viruses in cerebrospinal fluid (CSF) and serum of 18 patients with clinically definite multiple sclerosis (MS), 8 patients with optic neuritis (ON), 27 patients with other neurological disease (OND), and 88 control subjects without central nervous system disease. Serum antibody levels were not significantly different between the four groups. Differences in the frequency and levels of CSF antibodies between the four groups were observed. Control patients had serum/CSF antibody ratios from 2.0 to 3.0 (log) with an average of 2.5 corresponding to a 320-fold difference between serum and CSF antibody levels. MS patients had ratios from 1.1 to 2.1 with an average of 1.6. The average was 2.0 for the ON patients. The average for the OND patients was similar to the controls. The altered serum/CSF ratios for several viruses within an individual patient was similar. These results suggest that nonspecific immunostimulation is responsible for the increased levels of CSF virus antibodies.

Serological Investigation of the possibility of congenital transmission of papovavirus JC

In an examination of paired sera from pregnant women, 9 of 57 women who had JC virus antibodies in their first specimens exhibited virus reactivation, as judged by a fourfold or greater rise in JC virus hemagglutination-inhibiting antibodies; 43 women remained seronegative through pregnancy. JC virus-specific immunoglobulin M was not demonstrated in umbilical cord sera of six infants born to mothers showing reactivation or in 300 additional umbilical cord sera from normal pregnancies.

Comparison of hemagglutination inhibition test and enzyme-linked immunosorbent assay for determining antibody to rubella virus

The hemagglutination inhibition test (HAI) and the enzyme-linked immunosorbent assay (ELISA) for detecting antibody to rubella virus were compared by testing 25 sets of paired sera taken before and after infection and 10 sets of sera taken during acute and convalescent stages of the disease and by screening 700 serum samples from the Collaborative Perinatal Project, NIH/NINCDS. The tests were found to be comparable in their ability to detect positive and negative sera, rises in titers, and seroconversions. When a purified antigen and carefully prepared reagents were used, ELISA was found to be as accurate and reliable as HAI. ELISA required no pretreatment of serum, could easily be automated, and was less time-consuming than HAI.

CSF oligoclonal bands, immunoglobulins, and viral antibodies in progressive myoclonus epilepsy

We studied CSF and serum samples from 16 patients with progressive myoclonus epilepsy (PME). These patients had juvenile-onset PME with evidence of autosomal recessive inheritance and no Lafora bodies. Twelve of the 16 patients with PME had immunologic abnormalities. Oligoclonal gamma bands were seen in six of the eight patients from whom sufficient CSF was available. The CSF albumin and serum/CSF albumin ratios were normal in all 16 patients, indicating the presence of intact blood-brain barriers. Six of the 16 patients showed increased CSF IgG levels and five had an increased CNS IgG synthesis. All patients had normal serum and CSF IgM and IgA levels. Three patients, all with bands, had reduced measles and/or vaccinia serum/CSF antibody ratios. The findings suggest altered immune response of the CNS of some patients with PME apparently caused by nonspecific immunostimulation.

Serological investigation of BK papovavirus infection in pregnant women and their offspring

Paired sera from 150 pregnant women and 387 umbilical cord sera were tested for BK virus (BKV) antibodies. The hemagglutination inhibition, neutralization, and indirect immunofluorescence tests were employed for the detection of antibodies. Treatment of serum with anti-gamma Fc and tests of immunoglobulin M (IgM) fractions for antibodies were utilized as required to detect and validate the presence of virus-specific IgM. The BKV antibody prevalence in the sera collected at the time of the first prenatal visit was 75% by hemagglutination inhibition and 91% by neutralization tests. A total of 95% of the women had antibodies by at least one of the three serological tests. Five of 100 women with normal pregnancies exhibited BKV activity during pregnancy as evidenced by a greater than fourfold rise in BKV hemagglutination inhibition antibody titers and acquisition of BKV-specific IgM. The antibody rise occurred in the younger women and appeared to be a result of reactivation of the virus rather than of primary infection. Two instances of possible recent BKV infections were identified. BKV-specific IgM was not detected in any of the 387 umbilical cord sera which included three specimens from infants born to mothers with definite or probable BKV activity during pregnancy and 50 specimens with IgM levels of > 20 mg/100 ml. The results indicate that few women in the child-bearing age are nonimmune to BKV and that, although reactivation of infection occurs in pregnancy, congenital transmission of the virus either does not occur or is rare.

Swine influenza virus vaccination in patients with multiple sclerosis

A double-blind, placebo-controlled study was conducted to evaluate the safety and efficacy of inactivated influenza virus vaccines in patients with multiple sclerosis. The vaccine used contained 200 chick cell-agglutinating (CCA) units of influenza A/New Jersey/76 and 200 CCA units of influenza A/Victoria/75 whole viruses (Merrell-National Laboratories, Cincinnati, Ohio). The frequency of clinical relapses of multiple sclerosis was the same in the vaccine-treated (four of 33 patients) and placebo-treated (four of 33) groups. An untreated control group had a slightly higher rate of relapses (four of 22). Toxic reactions to the vaccine were not a significant problem. The efficacy of the vaccination as measured by titers of hemagglutination-inhibiting antibody was comparable to that reported for the general population. However, patients with preexisting antibody were less responsive to the vaccine than normal controls studied previously. The patients who did not respond to the vaccine tended to be older and more disabled. There were no changes in titers of antibody to rubeola or rubella virus after vaccination or in relation to change in clinical course. It is concluded that the vaccine is safe and effective in patients with multiple sclerosis.