Prevalence and co-occurrence of cognitive impairment in children and young people up to 12-months post infection with SARS-CoV-2 (Omicron variant)

BACKGROUND

Cognitive impairment is often reported after SARS-CoV-2 infection, yet evidence gaps remain. We aimed to (i) report the prevalence and characteristics of children and young people (CYP) reporting "brain fog" (i.e., cognitive impairment) 12-months post PCR-proven SARS-CoV-2 infection and determine whether differences by infection status exist and (ii) explore the prevalence of CYP experiencing cognitive impairment over a 12-month period post-infection and investigate the relationship between cognitive impairment and poor mental health and well-being, mental fatigue and sleep problems.

METHODS

The Omicron CLoCk sub-study, set up in January 2022, collected data on first-time PCR-test-positive and PCR-proven reinfected CYP at time of testing and at 3-, 6- and 12-months post-testing. We describe the prevalence of cognitive impairment at 12-months, indicating when it was first reported. We characterise CYP experiencing cognitive impairment and use chi-squared tests to determine whether cognitive impairment prevalence varied by infection status. We explore the relationship between cognitive impairment and poor mental health and well-being, mental fatigue and trouble sleeping using validated scales. We examine associations at 3-, 6- and 12-months post-testing by infection status using Mann-Whitney U and chi-square tests.

RESULTS

At 12-months post-testing, 7.0 % (24/345) of first-positives and 7.5 % (27/360) of reinfected CYP experienced cognitive impairment with no difference between infection-status groups (p = 0.78). The majority of these CYP experienced cognitive impairment for the first time at either time of testing or 3-months post-test (no difference between the infection-status groups; p = 0.60). 70.8 % of first-positives experiencing cognitive impairment at 12-months, were 15-to-17-years-old as were 33.3 % of reinfected CYP experiencing cognitive impairment (p < 0.01). Consistently at all time points post-testing, CYP experiencing cognitive impairment were more likely to score higher on all Strengths and Difficulties Questionnaire subscales, higher on the Chalder Fatigue sub-scale for mental fatigue, lower on the Short Warwick-Edinburgh Mental Wellbeing Scale and report more trouble sleeping.

CONCLUSIONS

CYP have a fluctuating experience of cognitive impairment by 12-months post SARS-CoV-2-infection. Cognitive impairment is consistently correlated with poorer sleep, behavioural and emotional functioning over a 12-month period. Clinicians should be aware of cognitive impairment post-infection and its co-occurring nature with poorer sleep, behavioural and mental health symptoms.

Feasibility, acceptability and preliminary effectiveness of a mental health drop-in centre for the siblings of young people attending a paediatric hospital

Siblings of children with long-term conditions (LTCs) can have significantly elevated mental health needs, but these are often overlooked. A pragmatic single-arm feasibility pilot assessed feasibility, acceptability and preliminary effectiveness of a drop-in centre in a paediatric hospital addressing mental health needs of patients with LTCs, their carers and siblings. The drop-in centre accepted self-referral and supplemented existing provision offering a suite of interventions, including signposting, diagnostic assessments and/or guided self-help. This paper reports on feasibility, acceptability and preliminary outcomes of this centre for siblings. Eighteen siblings aged 2-17 used the centre. Sixteen of their parents completed the Strengths and Difficulties Questionnaires at baseline and 6 months post-baseline, and ten completed parent-reported PedsQL across two time points. Preliminary effectiveness results demonstrated a decrease in mental health symptoms with large effect size (score reduction of 3.44, 95% CI [1.25, 5.63], d = 0.84) and small effect on quality of life, with scores increasing from a median of 69.91, 95% CI [53.57, 91.67], to a median of 80.44, 95% CI [67.39, 89.13], r = 0.11 for these siblings. 88% of parents were satisfied with this provision for their sibling child. This study highlights the feasibility and value of assessing siblings for emotional and behavioural difficulties and providing them with an accessible, effective and acceptable intervention.

[Arthroscopic biceps tenodesis with a «relaxed» technique.Clinical and radiological results of a prospective cohort]

INTRODUCTION

in the treatment the long head of the biceps tendon (LHBT) pathology, the «relaxed tenodesis» is an arthroscopic articular suprapectoral tenodesis that seeks to lower the tension on the LHBT, and therefore, theoretically avoid persistent pain.

OBJECTIVE

to assess clinical and radiological results of «relaxed» tenodesis in a prospective cohort of patient with work related illness.

MATERIAL AND METHODS

prospective cohort, 54 shoulders with «relaxed» tenodesis performed with an intra-articular interference screw by the same surgeon, from October 2014 to 2018, in a level 1 trauma center. Demographic, clinical, functional and radiologic results were analyzed. On 6 months follow-up, a sonographic and clinical assessment was performed.

RESULTS

mean age 49 ± 9, mean follow-up 16 ± 4 months. The main diagnosis was a rotator cuff tear in 79%, primary biceps pathology in 10% and other pathologies in 11%. At the end of follow-up, the cohort showed active anterior elevation 157.7 ± 22.7, external rotation 47 ± 16.6, median internal rotation T12, Constant Score 83 ± 12.05 points, subjective shoulder value 83 ± 12.97% and pain visual analogue scale 1.4 ± 1.7 points. One patient had a biceps tear and two had cosmetic arm asymmetry. On ultrasound 98% had the LHBT in situ and 10% had inflammatory changes on the bicipital groove. There were complications in 21% of the sample.

CONCLUSIONS

«relaxed biceps tenodesis» is a technique that shows good clinical, functional and sonographic results, with low failure rate.

Huntington's Disease in Chile: Epidemiological and Genetic Aspects

INTRODUCTION

Huntington's disease (HD) is a neurodegenerative, autosomal dominant disabling condition due to an expansion of the CAG trinucleotide in the HTT gene. Motor, psychiatric, and cognitive disorders characterize it. Chilean reports on HD in the era of molecular diagnosis were wanted.

METHODS

This is a retrospective analysis of a prospective cohort of patients with HD seen at the Center for Movement Disorders (CETRAM) in Chile between 2013 and 2019. Sociodemographic, genotype, and neuropsychiatric features were investigated.

RESULTS

One hundred three probands with HD were identified. The majority (63.1%) were born in the metropolitan region, followed by the VIII and V regions with 8.73% and 7.76%, respectively. When pedigrees were analyzed, ninety unrelated families encompassing 1,007 individuals were identified; among relatives, other 35 manifested HD, and 106 died of HD. Besides, five hundred seventy-nine individuals were at genetic risk. The minimum estimated prevalence of HD in Chile in 2019 was 0.72 × 100,000 inhabitants. The mean CAG repeats (CAGR) of 47.2 ± 10.74 for the expanded allele and 17.93 ± 2.05 for the normal allele. The mean age of onset was 41.39 ± 13.47 years. Juvenile cases represented 7.8% of this cohort, and 4.9% had a late onset. There was a negative correlation between the age of onset and the CAGR of the expanded allele (r =-0.84 p < 0.0001). Besides, 79.6% had a family history of HD.

CONCLUSIONS

This is the first report characterizing genetics, motor, and neuropsychiatric features in patients with HD in Chile. The mean length of CAGR expansion of the abnormal allele was similar to previous reports in North America (i.e., Mexico and Canada) and higher than that reported in the neighboring country of Argentina. According to previous estimations, the minimal prevalence of HD in Chile may be lower than expected.

Predictive model for long COVID in children 3 months after a SARS-CoV-2 PCR test

BACKGROUND

To update and internally validate a model to predict children and young people (CYP) most likely to experience long COVID (i.e. at least one impairing symptom) 3 months after SARS-CoV-2 PCR testing and to determine whether the impact of predictors differed by SARS-CoV-2 status.

METHODS

Data from a nationally matched cohort of SARS-CoV-2 test-positive and test-negative CYP aged 11-17 years was used. The main outcome measure, long COVID, was defined as one or more impairing symptoms 3 months after PCR testing. Potential pre-specified predictors included SARS-CoV-2 status, sex, age, ethnicity, deprivation, quality of life/functioning (five EQ-5D-Y items), physical and mental health and loneliness (prior to testing) and number of symptoms at testing. The model was developed using logistic regression; performance was assessed using calibration and discrimination measures; internal validation was performed via bootstrapping and the final model was adjusted for overfitting.

RESULTS

A total of 7139 (3246 test-positives, 3893 test-negatives) completing a questionnaire 3 months post-test were included. 25.2% (817/3246) of SARS-CoV-2 PCR-positives and 18.5% (719/3893) of SARS-CoV-2 PCR-negatives had one or more impairing symptoms 3 months post-test. The final model contained SARS-CoV-2 status, number of symptoms at testing, sex, age, ethnicity, physical and mental health, loneliness and four EQ-5D-Y items before testing. Internal validation showed minimal overfitting with excellent calibration and discrimination measures (optimism-adjusted calibration slope: 0.96575; C-statistic: 0.83130).

CONCLUSIONS

We updated a risk prediction equation to identify those most at risk of long COVID 3 months after a SARS-CoV-2 PCR test which could serve as a useful triage and management tool for CYP during the ongoing pandemic. External validation is required before large-scale implementation.

Long COVID (post-COVID-19 condition) in children: a modified Delphi process

OBJECTIVE

The aim of this study was to derive a research definition for 'Long COVID (post-COVID-19 condition)' in children and young people (CYP) to allow comparisons between research studies.

DESIGN

A three-phase online Delphi process was used, followed by a consensus meeting. Participants were presented with 49 statements in each phase and scored them from 1 to 9 based on how important they were for inclusion in the research definition of Long COVID in CYP. The consensus meeting was held to achieve representation across the stakeholder groups. Statements agreed at the consensus meeting were reviewed by participants in the Patient and Public Involvement (PPI) Research Advisory Group.

SETTING

The study was conducted remotely using online surveys and a virtual consensus meeting.

PARTICIPANTS

120 people with relevant expertise were divided into three panels according to their area of expertise: Service Delivery, Research (or combination of research and service delivery) and Lived Experience. The PPI Research Advisory group consisted of CYP aged 11-17 years.

MAIN OUTCOME MEASURES

Consensus was defined using existing guidelines. If consensus was achieved in two or more panels or was on the border between one and two panels, those statements were discussed and voted on at the consensus meeting.

RESULTS

Ten statements were taken forward for discussion in the consensus meeting and five statements met threshold to be included in the research definition of Long COVID among CYP. The research definition, aligned to the clinical case definition of the WHO, is proposed as follows: Post-COVID-19 condition occurs in young people with a history of confirmed SARS-CoV-2 infection, with at least one persisting physical symptom for a minimum duration of 12 weeks after initial testing that cannot be explained by an alternative diagnosis. The symptoms have an impact on everyday functioning, may continue or develop after COVID infection, and may fluctuate or relapse over time. The positive COVID-19 test referred to in this definition can be a lateral flow antigen test, a PCR test or an antibody test.

CONCLUSIONS

This is the first research definition of Long COVID (post-COVID-19 condition) in CYP and complements the clinical case definition in adults proposed by the WHO.

P-080 Intrauterine insemination (IUI) success rates in patients with suboptimal total processed motile sperm count (TPMSC) using a second consecutive semen sample

Study question

Is it effective to request a second consecutive semen sample in patients with less than 1 million TPMSC in a first semen sample for IUI?

Summary answer

In men with TPMSC under one million, the issuing of a second consecutive sample reached pregnancy rates similar to those published for IUI.

What is known already

IUI offers a comparable cumulative live birth rate in 3-4 cycles compared to IVF and can be preferred as a cost-effective first-line treatment in mild male factor or unexplained infertility. The quality of the processed semen sample is an important factor for the IUI success.

The WHO recommends an abstinence period to ensure best quality of semen samples. However, it has been observed that when men with moderate male factor who are unable to meet the minimum requirements for IUI are asked to produce a second sample better counts are obtained; questioning the time correlation between abstinence and semen quality.

Study design, size, duration

This was a retrospective study conducted in the reproductive medicine unit of a private hospital in Chile between July 2015 and March 2021. All patients who underwent IUI in the study period that had an TPMSC less than 1 million in the eyaculate and to whom a second consecutive sample was requested were included.

Participants/materials, setting, methods

118 patients who underwent 140 IUI cycles were included in the study. All the patients with an PMSC under 1 million at the time of the IUI were requested a second consecutive semen sample within an hour or two from the previous eyaculate. The second samples were processed and used for insemination. The primary outcome was pregnancy rate. The secondary outcomes were semen quality (TPMSC of first and second semen samples).

Main results and the role of chance

Between 2015 and 2021 there were 140 IUI cycles in which a second consecutive semen sample was requested, including 118 patients. Overall 17 pregnancies were achieved. The pregnancy rate per cycle was 12,14% and the pregnancy rate per patient was 14,4%. The live birth rate per patient was 10,2%.

Regarding the sperm sample analysis, the median TPMSC of the first semen sample was 261.437. The median PMSC of the second consecutive sample was 7.315.000. 126 patients had an TPMSC of 0 in the first semen sample while only 9 patients had an IMSC of 0 in the second sample. In five cases a third consecutive sample was requested of which 4 patients had their cycles canceled because they did not meet the target PMSC. One patient had an TPMSC of 1.687.000 in the third sample.

Finally, of the 118 patients who did not meet the requirements for IUI with the first sample, only 19 cycles were canceled.

Limitations, reasons for caution

The study has the limitation of being a retrospective and descriptive study with no contol group. Also the group is heterogeneous because it includes patients with different female factors for infertility.

Wider implications of the findings

In developing countries and low-income settings the IUI remains a more accessible alternative in patients with infertility. Routinely recollecting a second semen sample in men with TPMSC &lt;1 million would reduce cycle cancellation rates due to not achieving an optimal TPMSC, reaching pregnancy rates similar to those published for IUI.

Trial registration number

Not applicable

Physical and mental health 3 months after SARS-CoV-2 infection (long COVID) among adolescents in England (CLoCk): a national matched cohort study

BACKGROUND

We describe post-COVID symptomatology in a non-hospitalised, national sample of adolescents aged 11-17 years with PCR-confirmed SARS-CoV-2 infection compared with matched adolescents with negative PCR status.

METHODS

In this national cohort study, adolescents aged 11-17 years from the Public Health England database who tested positive for SARS-CoV-2 between January and March, 2021, were matched by month of test, age, sex, and geographical region to adolescents who tested negative. 3 months after testing, a subsample of adolescents were contacted to complete a detailed questionnaire, which collected data on demographics and their physical and mental health at the time of PCR testing (retrospectively) and at the time of completing the questionnaire (prospectively). We compared symptoms between the test-postive and test-negative groups, and used latent class analysis to assess whether and how physical symptoms at baseline and at 3 months clustered among participants. This study is registered with the ISRCTN registry (ISRCTN 34804192).

FINDINGS

23 048 adolescents who tested positive and 27 798 adolescents who tested negative between Jan 1, 2021, and March 31, 2021, were contacted, and 6804 adolescents (3065 who tested positive and 3739 who tested negative) completed the questionnaire (response rate 13·4%). At PCR testing, 1084 (35·4%) who tested positive and 309 (8·3%) who tested negative were symptomatic and 936 (30·5%) from the test-positive group and 231 (6·2%) from the test-negative group had three or more symptoms. 3 months after testing, 2038 (66·5%) who tested positive and 1993 (53·3%) who tested negative had any symptoms, and 928 (30·3%) from the test-positive group and 603 (16·2%) from the test-negative group had three or more symptoms. At 3 months after testing, the most common symptoms among the test-positive group were tiredness (1196 [39·0%]), headache (710 [23·2%]), and shortness of breath (717 [23·4%]), and among the test-negative group were tiredness (911 [24·4%]), headache (530 [14·2%]), and other (unspecified; 590 [15·8%]). Latent class analysis identified two classes, characterised by few or multiple symptoms. The estimated probability of being in the multiple symptom class was 29·6% (95% CI 27·4-31·7) for the test-positive group and 19·3% (17·7-21·0) for the test-negative group (risk ratio 1·53; 95% CI 1·35-1·70). The multiple symptoms class was more frequent among those with positive PCR results than negative results, in girls than boys, in adolescents aged 15-17 years than those aged 11-14 years, and in those with lower pretest physical and mental health.

INTERPRETATION

Adolescents who tested positive for SARS-CoV-2 had similar symptoms to those who tested negative, but had a higher prevalence of single and, particularly, multiple symptoms at the time of PCR testing and 3 months later. Clinicians should consider multiple symptoms that affect functioning and recognise different clusters of symptoms. The multiple and varied symptoms show that a multicomponent intervention will be required, and that mental and physical health symptoms occur concurrently, reflecting their close relationship.

FUNDING

UK Department of Health and Social Care, in their capacity as the National Institute for Health Research, and UK Research and Innovation.

Prediction of N95 Respirator Fit from Fogging of Eyeglasses: A Pilot Study

Aim and objective

Fogging of eyeglasses while wearing N95 respirators is common. It is commonly held that the N95 respirator has a poor fit if there is fogging of eyeglasses. We conducted this prospective, pilot study to determine if fogging of eyeglasses predicts poor fit of N95 respirator.

Materials and methods

Seventy volunteer healthcare workers from a tertiary intensive care unit in Sydney, Australia participated. The participants donned one of the following N95 respirators: three-panel flat-fold respirator (3M 1870), cup-shaped respirator (3M 1860), or a duckbill respirator. After a satisfactory "user seal check" as recommended by the manufacturer, the participants donned eyeglasses and checked for fogging. A quantitative fit test (QnFT) of the respirator was then performed (using PortaCount Respirator Fit Tester 8048, TSI Inc., Minnesota, USA). A fit factor of <100 on quantitative fit testing indicates poor fit. The sensitivity and specificity for fogging of eyeglasses (index test) to predict the poor fit of N95 respirator was determined, compared to QnFT (gold standard test).

Results

Fogging of eyeglasses as a predictor of poor respirator fit (i.e., fit factor <100 on QnFT) had sensitivity of 71% (95% CI, 54-85%) and specificity 46% (95% CI, 29-63%). The odds ratio of fogging as a predictor for poor fit was 2.10 (95% CI, 0.78-5.67), with a two-tailed p-value of 0.22 (not significant). The receiver operating characteristic curve for fogging of eyeglasses as a diagnostic test had the area under the curve of 0.59.

Conclusion

Fogging of eyeglasses is neither a sensitive nor a specific predictor for poor fit of N95 respirators.

How to cite this article

Kyaw S, Johns M, Lim R, Stewart WC, Rojas N, Thambiraj SR, et al. Prediction of N95 Respirator Fit from Fogging of Eyeglasses: A Pilot Study. Indian J Crit Care Med 2021;25(9):976-980.

[Actinomyces sp. brain abscess: a rare infection in children. A case report]

Despite advances in diagnostic and treatment techniques, intracranial infections remain serious diseases with an estimated incidence of between 0.3 and 1.3 cases/100,000 inhabitants. We present a previously healthy patient with an intraoperative diagnostic of brain abscess, in whom although the culture showed polymicrobial development, Actinomyces sp was presumptively identified in the pathological anatomy. Given this finding, prolonged combined antibiotic therapy was performed with good evolution. Absceso cerebral por Actinomyces sp.: una infección infrecuente en niños. A propósito de un caso Actinomyces sp. brain abscess: a rare infection in children. A case report The presentation of this suppurative process was nonspecific and the contribution of the anatomopathology in the etiological diagnosis was relevant. The identification of an unusual microorganism defined the need to deepen the identification of predisposing factors.

Long COVID and the mental and physical health of children and young people: national matched cohort study protocol (the CLoCk study)

INTRODUCTION

There is uncertainty surrounding the diagnosis, prevalence, phenotype, duration and treatment of Long COVID. This study aims to (A) describe the clinical phenotype of post-COVID symptomatology in children and young people (CYP) with laboratory-confirmed SARS-CoV-2 infection compared with test-negative controls, (B) produce an operational definition of Long COVID in CYP, and (C) establish its prevalence in CYP.

METHODS AND ANALYSIS

A cohort study of SARS-CoV-2-positive CYP aged 11-17 years compared with age, sex and geographically matched SARS-CoV-2 test-negative CYP. CYP aged 11-17 testing positive and negative for SARS-CoV-2 infection will be identified and contacted 3, 6, 12 and 24 months after the test date. Consenting CYP will complete an online questionnaire. We initially planned to recruit 3000 test positives and 3000 test negatives but have since extended our target. Data visualisation techniques will be used to examine trajectories over time for symptoms and variables measured repeatedly, separately by original test status. Summary measures of fatigue and mental health dimensions will be generated using dimension reduction methods such as latent variables/latent class/principal component analysis methods. Cross-tabulation of collected and derived variables against test status and discriminant analysis will help operationalise preliminary definitions of Long COVID.

ETHICS AND DISSEMINATION

Research Ethics Committee approval granted. Data will be stored in secure Public Health England servers or University College London's Data Safe Haven. Risks of harm will be minimised by providing information on where to seek support. Results will be published on a preprint server followed by journal publication, with reuse of articles under a CC BY licence. Data will be published with protection against identification when there are small frequencies involved.

TRIAL REGISTRATION NUMBER

ISRCTN34804192; Pre-results.

Self-organization and energy of superparamagnetic nets

Superparamagnetic filaments assemble, building one-layered aggregates due to the screening effect inherited from the dipole interaction potential in a colloidal blend. The magnetic energy of rectangular and irregular ribbons is computed to obtain their mean length at thermodynamic equilibrium, in good agreement with experimental measurements.

A qPCR Targeted Against the Viral Replication Origin Designed to Quantify Total Amount of Filamentous Phages and Phagemids

Filamentous bacteriophages are widely used in phage display technology. The most common quantification method is lysis plaque formation test (PFT). This technique has several disadvantages, and only quantifies infective phages and is not effective when phagemids are used. We developed a qPCR method directed against the M13 replication origin, which detects between 3.3 × 10³ and 3.3 × 10⁸ viral genome copies with a linearity of R ²  = 0.9998. Using this method we were able to observe a difference of approximately ten more phages than with the PFT. This difference was not due to the presence of a free genome, which suggests the presence of non-infective particles. Using a DNaseI treatment, we observed the presence of 30% to 40% of unpackaged genome in recombinant phage modified in PIII or PVIII. The qPCR method with a DNase I treatment is an efficient method to quantify the total amount of filamentous phages.

A Descriptive Analysis of the Interactions During Clinical Supervision

This study intends to analyze some skills trained during supervision. In it we describe sets of interactions (based on the American Psychological Association [APA], 2006; competency domains) happened between the supervisor and the supervisee during the supervision process. Interactions from twelve supervisor-supervisee dyads during asynchronous and direct, and individual and group supervision sessions were video recorded for this purpose. The recordings helped to determine, classify, and define behavioral response classes in each dyad's interactions. Percentages of time spent in each behavior class were computed. A reliability of 95% CI [0.91, 0.95] among observers was obtained. The behavior classes in which more time was spent were assessment, intervention, and conceptualization skills. Behavior classes in which less time was spent were related to emotional and interpersonal processes. These findings are discussed by linking the evidence-based theory on supervision with the time spent in each behavior class.

Reconstruction of the microalga Nannochloropsis salina genome-scale metabolic model with applications to lipid production

Background

Nannochloropsis salina (= Eustigmatophyceae) is a marine microalga which has become a biotechnological target because of its high capacity to produce polyunsaturated fatty acids and triacylglycerols. It has been used as a source of biofuel, pigments and food supplements, like Omega 3. Only some Nannochloropsis species have been sequenced, but none of them benefit from a genome-scale metabolic model (GSMM), able to predict its metabolic capabilities.

Results

We present iNS934, the first GSMM for N. salina, including 2345 reactions, 934 genes and an exhaustive description of lipid and nitrogen metabolism. iNS934 has a 90% of accuracy when making simple growth/no-growth predictions and has a 15% error rate in predicting growth rates in different experimental conditions. Moreover, iNS934 allowed us to propose 82 different knockout strategies for strain optimization of triacylglycerols.

Conclusions

iNS934 provides a powerful tool for metabolic improvement, allowing predictions and simulations of N. salina metabolism under different media and genetic conditions. It also provides a systemic view of N. salina metabolism, potentially guiding research and providing context to -omics data.

Electronic supplementary material

The online version of this article (doi:10.1186/s12918-017-0441-1) contains supplementary material, which is available to authorized users.

Self-assembly processes of superparamagnetic colloids in a quasi-two-dimensional system

Superparamagnetic colloids gather depending on the magnitude of the magnetic field applied, forming chains and ribbons in a quasi-two-dimensional chamber. The results presented in this work are in good agreement with recent experimental multistable data for the mean length of the aggregates in thermodynamic equilibrium.

The fern cavitation catapult: mechanism and design principles

Leptosporangiate ferns have evolved an ingenious cavitation catapult to disperse their spores. The mechanism relies almost entirely on the annulus, a row of 12-25 cells, which successively: (i) stores energy by evaporation of the cells' content, (ii) triggers the catapult by internal cavitation, and (iii) controls the time scales of energy release to ensure efficient spore ejection. The confluence of these three biomechanical functions within the confines of a single structure suggests a level of sophistication that goes beyond most man-made devices where specific structures or parts rarely serve more than one function. Here, we study in detail the three phases of spore ejection in the sporangia of the fern Polypodium aureum. For each of these phases, we have written the governing equations and measured the key parameters. For the opening of the sporangium, we show that the structural design of the annulus is particularly well suited to inducing bending deformations in response to osmotic volume changes. Moreover, the measured parameters for the osmoelastic design lead to a near-optimal speed of spore ejection (approx. 10 m s(-1)). Our analysis of the trigger mechanism by cavitation points to a critical cavitation pressure of approximately -100 ± 14 bar, a value that matches the most negative pressures recorded in the xylem of plants. Finally, using high-speed imaging, we elucidated the physics leading to the sharp separation of time scales (30 versus 5000 µs) in the closing dynamics. Our results highlight the importance of the precise tuning of the parameters without which the function of the leptosporangium as a catapult would be severely compromised.

Cefazolin high-inoculum effect in methicillin-susceptible Staphylococcus aureus from South American hospitals

OBJECTIVES

Clinical failures with cefazolin have been described in high-inoculum infections caused by methicillin-susceptible Staphylococcus aureus (MSSA) producing type A β-lactamase. We investigated the prevalence of the cefazolin inoculum effect (InE) in MSSA from South American hospitals, since cefazolin is used routinely against MSSA due to concerns about the in vivo efficacy of isoxazolyl penicillins.

METHODS

MSSA isolates were recovered from bloodstream (n = 296) and osteomyelitis (n = 68) infections in two different multicentre surveillance studies performed in 2001-02 and 2006-08 in South American hospitals. We determined standard-inoculum (10(5)cfu/mL) and high-inoculum (10(7) cfu/mL) cefazolin MICs. PFGE was performed on all isolates that exhibited a cefazolin InE. Multilocus sequence typing (MLST) and sequencing of part of blaZ were performed on representative isolates.

RESULTS

The overall prevalence of the cefazolin InE was 36% (131 isolates). A high proportion (50%) of MSSA isolates recovered from osteomyelitis infections exhibited the InE, whereas it was observed in 33% of MSSA recovered from bloodstream infections. Interestingly, Ecuador had the highest prevalence of the InE (45%). Strikingly, 63% of MSSA isolates recovered from osteomyelitis infections in Colombia exhibited the InE. MLST revealed that MSSA isolates exhibiting the InE belonged to diverse genetic backgrounds, including ST5, ST8, ST30 and ST45, which correlated with the prevalent methicillin-resistant S. aureus clones circulating in South America. Types A (66%) and C (31%) were the most prevalent β-lactamases.

CONCLUSIONS

Our results show a high prevalence of the cefazolin InE associated with type A β-lactamase in MSSA isolates from Colombia and Ecuador, suggesting that treatment of deep-seated infections with cefazolin in those countries may be compromised.

[Hypercholesterolemia reduction in children and adolescents after two years of intervention]

INTRODUCTION

Hypercholesterolemia, one of the main risk factors for cardiovascular diseases, can be detected since childhood. The early detection and a suitable educational process would allow to generate changes of habits and to decrease its prevalence. In 2003, total cholesterol (TC) > 170 mg/dl was found in 39.2% school children and adolescents, aged 5-17 years, of Jovita, Córdoba.

OBJECTIVE

To assess cholesterol levels decrease after an educational process and to analyze the relation between hypercholesterolemia and family history for cardiovascular diseases.

METHODS

Formal and no formal educational intervention was developed for two years, through curricular adaptations, talks, campaigns in radio and TV, graphic press, drama, workshops and leaflets. In 2005, cholesterol level was assessed, along with a survey on changes of nutritional habits and physical activity, and family history.

RESULTS

A group of 161 students was assesses in both opportunities. There was a significant reduction in total cholesterol (average 13 mg/dl; p< 0.0000), 51 students (31.7%) normalized their TC values (<170 mg/dl). The effect of regression to the average was 3 mg/dl. In a group of 66 students with TC > 199 mg/dl, the variations of the averages were: TC= -21 mg/dl, LDL-C= -16 mg/dl. The survey revealed improvements in the habits; family history was positive in 59%, unknown in 14%, and negative in 27%, the last ones had the best response to the intervention.

CONCLUSION

A significant reduction of TC was obtained in the studied population; this may be due to the educational intervention. More than a quarter of the individuals presented negative family history for cardiovascular risk factors. Decrease in TC was proportionally better in this group than in those with positive family history.

Testicular adrenal rest tumors and Leydig and Sertoli cell function in boys with classical congenital adrenal hyperplasia

CONTEXT

Infertility observed in adult males with congenital adrenal hyperplasia (CAH) has been associated with testicular adrenal rest tumors (TART) that may originate during childhood.

OBJECTIVE

Our objective was to describe the prevalence of TART and Sertoli and Leydig cell function in a group of boys aged 2-10 yr with CAH and to compare prevalence with that of a control group.

DESIGN

From August 2005 to January 2007, 19 patients with classical CAH (CAH group) were referred from seven endocrinology centers.

METHODS

We studied 19 subjects in the CAH group and, as a control group, 13 boys from the community that did not have testicular diseases. A complete physical exam was performed. High-resolution ultrasound was used to determine TART prevalence. Inhibin B and anti-Müllerian hormone were used as Sertoli cell markers. The ratio between basal testosterone levels and testosterone levels 72 h after beta-human chorionic gonadotropin (5000 U/m2) treatment [(T72- T0)/T0] was used to evaluate Leydig cell response.

RESULTS

CAH and control groups were comparable in chronological age (5.9 vs. 5.6 yr; P = 0.67) and bone age/chronological age ratio (1.09 vs. 1.03; P = 0.09). TART prevalence was four of 19 (21%) in the CAH group. Lower values for inhibin B (49.2. vs. 65.2 pg/ml; P = 0.018), anti-Müllerian hormone (70.1 vs. 94.2 ng/ml; P = 0.002), and (T72- T0)/T0 (5.6 vs. 13.6; P < 0.01) were observed in the CAH group.

CONCLUSION

TART in prepubertal males with classic CAH could be found during childhood. We also report differences in markers of gonadal function in a subgroup of patients, especially in those with inadequate control.

Improvement of reproductive performance in crossbred zebu anestrous primiparous cows by treatment with norgestomet implants or 96 h calf removal

The aim of the present study was to compare the effect of norgestomet implants (NI) and calf removal (CR) for 96 h on estrus induction and first service fertility in crossbred zebu primiparous anestrous cows after 120 days postpartum. A total of 152 cows in a tropical environment were allotted to three experimental groups: CR for 96 h (n = 51), NI for 9 days plus 500 IU of PMSG at implant removal (n = 51) and a control group (CG) without treatment (n = 50). Estrous rate (%) and mean interval to first estrus (days) were 50.9 and 26.3+/-6.8; 60.7 and 13.8+/-6.8; 16.0% and 61.8+/-5.9 days for groups CR, NI and CG, respectively. CR and NI were statistically similar, however, both groups were different (P < 0.01) when compared with CG. Calving interval to first service and to conception were: CR: 151.2+/-8.4 and 157.8+/-21.4; NI: 145.2+/-8.5 and 150.9+/-21.3; CG: 186.8+/-7.3 and 201.0+/-18.5. A difference (P < 0.01) was found in both intervals when comparing the CR and NI with CG, with longer intervals for cows in the CG group. First service conception rates were 61.5, 67.7 and 62.5% for groups CR, NI and CG, respectively, and were not different (P > 0.05). These results demonstrate the efficacy of NI + PMSG or temporary CR for 96 h in inducing a fertile estrus and shortening the interval to estrus and to conception in primiparous crossbred anestrous zebu cows in the tropics.

Comparison of the antibody response in adult cattle against different epitopes of Brucella abortus lipopolysaccharide

The comparison of serological responses in a sample of adult, vaccinated and held-infected bovines with Brucella abortus is reported. Indirect enzyme immunoassav (EIA) titration curves and Western blotting tests for smooth-type lipopolysaccharide (S-LPS), rough-type LPS (R-LPS) and lipid A were performed. In the initial screening of sera, an overall prevalence of 20.5% was found, which corresponds to a country with a high incidence of brucellosis. End-point EIA titres against LPS antigens from vaccinated and field-infected cows were not significantly different. However, the absorbance values in the titration curves were significantly higher for S-LPS as compared with the other antigens. A high correlation coefficient (r = 0.933) was obtained when the titres to R-LPS versus lipid A were compared. Western blotting reactions of vaccinated and held-infected animals were indistinguishable. S-LPS, R-LPS and lipid A epitopes were recognized in a heterogeneous manner. In general, the number of bovines that reacted against LPS was higher in the field-infected group, with a stronger binding to S-LPS. Based on our observations, the vaccinated and field-infected bovines are capable of producing similar antibody responses to the Brucella main outer surface antigen, LPS. It should be emphasized that the humoral response of cattle to Brucella LPS contains significant amounts of antibodies to other antigenic moieties of this important surface molecule, which may contribute to the immunity to brucellosis.

Modulation of the susceptibility of human erythrocytes to snake venom myotoxic phospholipases A(2): role of negatively charged phospholipids as potential membrane binding sites

Cerrophidion (Bothrops) godmani myotoxins I (CGMT-I) and II (CGMT-II), Asp-49 and Lys-49 phospholipases A(2) (PLA2s), which drastically differ in enzymatic activity, were devoid of direct hemolytic effects on erythrocytes (RBC) from different species despite the fact that enzymatically active CGMT-I was able to hydrolyze RBC membrane phospholipids and disrupt liposomes prepared from RBC lipids. Human RBC did not become susceptible to the toxins after treatment with neuraminidase or after altering membrane fluidity with cholesterol or sublytic concentrations of detergent. Unlike normal RBC, significant hemolysis was induced by CGMT-II and another similar Lys-49 isoform, B. asper MT-II (BAMT-II), in RBC enriched with phosphatidylserine (PS). Hemolysis was greater in RBC preincubated with pyridyldithioethylamine (PDA), a potent inhibitor of aminophospholipid transport. RBC enriched with phosphatidic acid (PA) also became susceptible to the myotoxins but was unaffected by PDA. Cells enriched with phosphatidylcholine (PC) remained resistant to the action of the toxins. BAMT-II also induced damage in black lipid membranes prepared with PS but not PC alone. When RBC binding of BAMT-II was measured by enzyme-linked immunosorbent assay, it was observed that PS- and PA-enriched erythrocytes were always able to capture more toxin than normal and PC-enriched RBC. This effect was significantly improved by PDA (in the case of PS) and it was observed either in the presence or in the absence of calcium in the medium. These data suggest that negatively charged lipids in the outer leaflet of cell membranes constitute myotoxic PLA2 binding sites. The scarcity of anionic phospholipids in the outer leaflet of RBC could explain their resistance to the action of these PLA2s.

Substance abuse and criminal recidivism: a prospective study of adolescents

Studies of substance abuse among delinquents have shown mixed results on criminal recidivism. The present study evaluates personality traits associated with substance abuse and recidivism among delinquent boys, and prospectively determines the extent to which these factors are predictive of criminal recidivism. 134 incarcerated boys (x = 15.9 +/- 1.1) completed the Weinberger Adjustment Inventory and the Substance Abuse Screening Inventory. Youth were prospectively followed for up to 4.5 years following release. Among incarcerated delinquents, personality traits are predictive of a positive substance abuse screen and recidivism. A trend indicating a possible interaction between personality and treatment is observed. If these findings are replicated, personality traits may play a role in predicting substance abuse as well as individual delinquent responses to treatment.

[In vitro immunosuppressive effect of low density lipoproteins]

BACKGROUND

Immune cells participate in the formation of atheromatous plate, however little is known about the effects of native or oxidatively modified lipoproteins on these cells.

AIM

To study the effects of lipoproteins on in vitro mononuclear cell proliferation.

MATERIAL AND METHODS

Peripheral blood mononuclear cells were obtained from 10 patients with type 2 diabetes mellitus (aged 52 +/- 9 years old with a disease duration of 8.2 +/- 5.7 years and a mean glycosilated hemoglobin of 9.3 +/- 2.2%) and 10 non diabetic healthy controls (aged 50.3 +/- 7.1 years old). These were stimulated with phytohemagglutinin (PHA) alone or in the presence of native LDLS, malondialdehyde modified LDLs or glycated LDLs. Proliferation was measured as 3H-thymidine incorporation and expressed as Stimulation Index (SI).

RESULTS

SI of patients and healthy subjects, after PHA stimulation were similar: (57.5 +/- 29.8 and 61.1 +/- 23.5) respectively LDLs did not induce proliferation in neither group. Native LDLs produced a 98% inhibition of PHA induced proliferation. Malondialdehyde modified and glycated LDLs caused a 50% inhibition. The suppressive effect was maintained when lipoproteins were incorporated to culture media 60 min prior or after PHA stimulation.

CONCLUSIONS

Lipoproteins inhibit in vitro PHA induced peripheral blood mononuclear cell proliferation both in diabetic and in non diabetic subjects.

A polyisoprenylated benzophenone from Cuban propolis

A novel polyisoprenylated benzophenone (1) has been isolated from an ethanol extract of Cuban propolis. Its structure has been determined using high-field 2D NMR techniques. Compound 1 showed significant antimicrobial and antifungal activity against a variety of bacteria and yeasts.

[Immune response against modified low-density lipoproteins in patients with non-insulin-dependent diabetes mellitus]

BACKGROUND

Diabetes mellitus is a risk factor for atherosclerosis. Low density lipoproteins are considered a key factor in the formation of atheroma and the immune system has an important contribution to this process.

AIM

To quantify the immune response against modified low density lipoproteins in patients with non insulin dependent diabetes mellitus.

MATERIAL AND METHODS

LDLs obtained from blood of healthy subjects, were glycated or altered with malondialdehyde and used as antigens. Serum autoantibodies against these LDLs were measured by ELISA in 22 patients with non insulin dependent diabetes mellitus aged 46 to 67 years old and 13 healthy controls aged 41 to 65 years old. Basal and LDL stimulated tumor necrosis factor a production in vitro, by peripheral leukocytes of diabetics and controls was also measured.

RESULTS

The ratio of glycated LDL/native LDL antibodies was higher in diabetics than in controls (9.37 +/- 2.72 and 0.41 +/- 0.11 respectively p < 0.05) and the ratio of MDA modified LDL/native LDL antibodies was not significantly different (8.64 +/- 3.83 and 2.14 +/- 1.26 respectively, NS). Tumor necrosis or production by leukocytes was higher in diabetics than in controls in basal conditions (53.3 +/- 15.3 and 26.9 +/- 14.7 arbitrary units (a.u.) respectively), when stimulated with native LDL (46.5 +/- 5 and 24.3 +/- 9.4 a.u. respectively), when stimulated with malondialdehyde modified LDL (50 +/- 16.2 and 24.4 +/- 7.7 a.u. respectively) or when stimulated with glycated LDL (38.3 +/- 8.8 and 14.4 +/- 7.5 a.u. respectively).

CONCLUSIONS

Diabetic patients have an enhanced immune response against low density lipoproteins, factor that could contribute to the accelerated atherogenesis of this disease.

Heterogeneity of Brucella abortus lipopolysaccharides

This work demonstrates that Brucella lipopolysaccharide (LPS) preparations are a family of related molecules which display heterogeneity not only at the level of the O polysaccharide, but also at the core oligosaccharide and the lipid A. Sodium dodecyl sulphate/polyacrylamide gel electrophoresis and Western blotting showed that LPS from Brucella strains displayed molecular weight and antigenic heterogeneity. Smooth-type LPS (S-LPS) from B. abortus demonstrated three broad high-molecular-weight bands corresponding to S-LPS, and a low-molecular-weight band corresponding to O antigen lacking rough-type LPS (R-LPS). B. abortus R-LPS displayed four bands in increasing proportions as the molecular weight diminished. Immunodetection on high-performance thin-layer chromatography (HPTLC) with monoclonal antibodies (mAb) showed that R-LPS displayed three diffuse bands. HPTLC of O polysaccharide revealed two fast migrating bands recognized by antibodies. Gel chromatography and HPTLC analysis of core oligosaccharides from R-LPS demonstrated molecular weight heterogeneity as well as heterogeneous banding pattern, with no obvious correspondence between the two profiles. Immunodetection of lipid A on HPTLC plates revealed two major and three minor bands. Reactivity with mAbs suggested that regardless of the lipid A heterogeneity the basic structure of lipid A backbone is maintained.

[Significance of human leptospirosis in Mexico. Detection of Leptospira antibodies in a blood donor population]

The presence of specific serum antibodies has been used as a diagnostic test for human leptospirosis. The presence of these antibodies in humans is indicative of an active natural infection. Its detection after exposure denotes the presence of immunity. Serum samples from 206 adult blood donors were analyzed with a microscopic agglutination assay against 7 serovars of Leptospira interrogans. A total of 7% were positive with the following serovar distribution; shermani 53%, canicola 33%, pyrogens 20%, pomona 13% and icterohaemorrhagiae 6%. The highest frequency of seropositivity was found in the 20 year to 39 age group. These results in asymptomatic individuals show that leptospirosis is a frequent zoonosis in Mexico.

Immunochemical identification of Brucella abortus lipopolysaccharide epitopes

Sera from Brucella abortus-infected and -vaccinated bovines recognized four lipopolysaccharide (LPS) determinants: two in the O-polysaccharide (A and C), one in the core oligosaccharide from rough Brucella LPS (R), and one in lipid A (LA). From 46 different hybridomas secreting monoclonal antibodies (MAbs) against various LPS moieties, 9 different specificities were identified. Two epitopes, A and C/Y, were present in the O-polysaccharide. Two epitopes were found in the core oligosaccharide (R1 and R2) of rough Brucella LPS. MAbs against R1 and R2 epitopes reacted against LPS from different rough Brucella species; however, MAbs directed to the R2 epitope also reacted against enterobacterial LPS from deep rough mutants. Three epitopes (LA1, LA2, and LA3) were located in the lipid A backbone. Different sets of MAbs recognized two epitopes in the lipid A-associated outer membrane protein (LAOmp3-1 and LAOmp3-2). LPS preparations from smooth brucellae had small amounts of rough-type LPS. Although LPS from rough brucellae did not show smooth-type LPS in western blots (immunoblots), two hybridomas generated from mice immunized with rough B. abortus produced antibodies against smooth B. abortus LPS. Results are discussed in relation to the structure and function of B. abortus LPS and to previous findings on the epitopic density of the molecule.

[Persistent microalbuminuria in insulin-dependent diabetics and cardiovascular risk factors]

A possible association of cardiovascular risk factors and early diabetic nephropathy was investigated in 32 patients. Microalbuminuria (radioimmunoassay), total and HDL cholesterol and triglycerides (enzymatic methods), glycosylated hemoglobin (colorimetric methods), Apo A1 and B (immunonephelometric) and LDL were measured. Microalbuminuria was present in 28% of patients. Compared to subjects with no microalbuminuria they had increased levels of cholesterol (200.2 +/- 13.5 (SE) vs 168.6 +/- 9.4 mg/dl, p < 0.025) and LDL cholesterol (171.9 +/- 14.1 vs 137.4 +/- 9.1 mg/dl, p < 0.025). Systolic blood pressure was also higher in patients with microalbuminuria (127.8 +/- 3.9 vs 114.5 +/- 2.8 mmHg, p < 0.01). Microalbuminuria was correlated to the level of diastolic blood pressure (r = 0.74, p < 0.025). Thus, persistent microalbuminuria in insulin dependent diabetic patients is associated to cardiovascular risk factors which may explain the increased cardiovascular morbidity and mortality in these patients.

[Tuberculosis and diabetes mellitus: a longitudinal-retrospective study in a teaching hospital]

We analyzed 1529 diabetic patients seen between 1959 and 1982 at a teaching hospital in Concepción, Chile. 116 of them were insulin dependent diabetics. Gestational diabetes was excluded. The 10 year actuarial risk of acquiring tuberculosis was 24.2% for insulin-dependent diabetics and 4.8% for the rest (p less than 0.001). The risk of the diabetic population as a whole was 5.9% compared to 0.8% for the population at large. Thus, diabetics are a high risk group for tuberculosis, especially insulin-dependent patients whose risk is about 38 times higher than the general population under 40 years of age.

[Spermatogonia types in tepezcuintle (Cuniculus paca). Ultrastructural study]

Ultrastructural studies of different types of spermatogonia by thin section techniques and transmission electron microscopy showed that Cuniculus paca has two types of Type A spermatogonia (A-O and A-1). Samples were taken at different stages of the cycle in the seminiferous tubule epithelium presented a similar pattern as those of other rodents. Type B spermatogonia are similar to those of the rat, the difference being that the heterochromatic zones are larger and more numerous. Both characteristics differentiate them from preleptotenic spermatocytes.