The effect of long-term storage on measured plasma lactate concentrations and prospective lactate results from a multicenter trial of antiretroviral therapy

2005 ◽  
Vol 43 (9) ◽  
Author(s):  
Michael P. Dubé ◽  
Douglas W. Kitch ◽  
Robert A. Parker ◽  
Beverly L. Alston-Smith ◽  
Kathleen Mulligan
Keyword(s):  
Antiretroviral Therapy ◽  
Real Time ◽  
Mixed Model ◽  
Linear Mixed Model ◽  
Frozen Storage ◽  
Multicenter Trial ◽  
Plasma Lactate ◽  
Handgrip Exercise ◽  
Potassium Oxalate ◽  
Long Term Storage

AbstractPlasma lactate measurements are typically performed in real time, limiting their usefulness in multicenter or longitudinal studies. To determine the stability of lactate specimens, blood was drawn in sodium fluoride/potassium oxalate tubes from 13 volunteers before and after 5min of handgrip exercise to intentionally increase lactate concentrations. Plasma was stored at −70°C. Aliquots were assayed in real time and after 1, 3, 6, 9, 12, 18, and 24months. Real-time lactate concentrations measured at baseline ranged from 0.52 to 2.23mmol/L before and from 2.91 to 11.04mmol/L after handgrip exercise. Using a linear mixed model, the estimated change from baseline at month 24 was 1.67% (95% confidence interval, −0.70% to 4.03%) for pre-exercise samples and 0.39% (95% CI, −1.13% to 1.91%) for post-exercise samples. Stored serial specimens from 232 HIV-infected subjects in a multicenter trial of antiretroviral therapy were also assayed centrally. Among those, median plasma lactate increased from baseline to 64weeks by 0.4mmol/L with zidovudine+lamivudine treatment and by 0.6mmol/L with didanosine+stavudine (each p<0.001 from baseline; p=0.04 for difference between groups over time). When performed as in this study, frozen storage with central batch lactate analysis is appropriate for prospectively collected samples in multicenter trials.

scholarly journals Estimates of the Time From Seroconversion to Antiretroviral Therapy Initiation Among People Newly Diagnosed With Human Immunodeficiency Virus From 2006 to 2015, New York City

2019 ◽  
Vol 71 (8) ◽  
pp. e308-e315
Author(s):  
McKaylee M Robertson ◽  
Sarah L Braunstein ◽  
Donald R Hoover ◽  
Sheng Li ◽  
Denis Nash
Keyword(s):  
Human Immunodeficiency Virus ◽  
Antiretroviral Therapy ◽  
Hiv Testing ◽  
Mixed Model ◽  
Linear Mixed Model ◽  
Population Based ◽  
Cd4 Count ◽  
Hiv Diagnosis ◽  
Art Initiation ◽  
Immunodeficiency Virus

Abstract Background We estimated the time from human immunodeficiency virus (HIV) seroconversion to antiretroviral therapy (ART) initiation during an era of expanding HIV testing and treatment efforts. Methods Applying CD4 depletion parameters from seroconverter cohort data to our population-based sample, we related the square root of the first pretreatment CD4 count to time of seroconversion through a linear mixed model and estimated the time from seroconversion. Results Among 28 162 people diagnosed with HIV during 2006–2015, 89% initiated ART by June 2017. The median CD4 count at diagnosis increased from 326 (interquartile range [IQR], 132–504) cells/µL to 390 (IQR, 216–571) cells/µL from 2006 to 2015. The median time from estimated seroconversion to ART initiation decreased by 42% from 6.4 (IQR, 3.3–11.4) years in 2006 to 3.7 (IQR, 0.5–8.3) years in 2015. The time from estimated seroconversion to diagnosis decreased by 28%, from a median of 4.6 (IQR, 0.5–10.5) years to 3.3 (IQR, 0–8.1) years from 2006 to 2015, and the time from diagnosis to ART initiation reduced by 60%, from a median of 0.5 (IQR, 0.2–2.1) years to 0.2 (IQR, 0.1–0.3) years from 2006 to 2015. Conclusions The estimated time from seroconversion to ART initiation was reduced in tandem with expanded HIV testing and treatment efforts. While the time from diagnosis to ART initiation decreased to 0.2 years, the time from seroconversion to diagnosis was 3.3 years among people diagnosed in 2015, highlighting the need for more effective strategies for earlier HIV diagnosis.

scholarly journals Long-Term Stability of 18 Nutritional Biomarkers Stored at −20 °C and 5 °C for up to 12 Months

2018 ◽  
Vol 3 (1) ◽  
pp. 100-108
Author(s):  
Huiping Chen ◽  
Maya R Sternberg ◽  
Rosemary L Schleicher ◽  
Christine M Pfeiffer
Keyword(s):  
Mixed Model ◽  
Linear Mixed Model ◽  
Iron Status ◽  
Geometric Mean ◽  
Water Soluble ◽  
Reference Condition ◽  
Term Stability ◽  
Long Term Stability ◽  
Long Term Storage

Abstract Background Consistent information on long-term storage stability for a broad range of nutritional biomarkers is lacking. We investigated the stability of 18 biomarkers stored at suboptimal temperatures (−20 °C and 5 °C) for up to 12 months. Methods Multiple vials of serum or whole blood pools (3 concentrations) were stored at −20 °C or 5 °C, removed from the −20 °C freezer after 3, 6, 9, and 12 months and from the 5 °C refrigerator after 6 and 12 months, and placed into a −70 °C freezer until analysis at study completion. Vials stored continuously at −70 °C were used as the reference condition for optimal storage. We measured 18 biomarkers: 4 iron status, 1 inflammation, 8 water-soluble vitamin, and 5 fat-soluble vitamin. For each temperature, we calculated geometric mean concentrations and average percent changes of geometric means across pools relative to the reference condition estimated from a linear mixed model. Results Most biomarkers (13 of 18) showed no difference in concentration after 12 months of storage at −20 °C. Serum ferritin (1.5%), soluble transferrin receptor (−1.7%), and folate (−10.5%) showed small to moderate significant changes at 6 months, but changes were acceptable based on biologic variability. Serum pyridoxal-5′-phosphate (−18.6% at 9 months) and vitamin C (−23% at 6 months) showed large and unacceptable changes at −20 °C. All serum fat-soluble vitamins and iron status indicators, vitamin B12, total homocysteine, and methylmalonic acid showed acceptable changes when stored at 5 °C for up to 12 months. Conclusions Overall, we found good long-term stability for multiple nutritional biomarkers stored at suboptimal temperatures.

scholarly journals PSVII-28 Program Chair Poster Pick: Effects of SMAD6 and SUGCT genes on Litter traits in pigs

2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 463-464
Author(s):  
Lyubov Getmantseva ◽  
Siroj Bakoev ◽  
Varvara Shevtsova ◽  
Nekruz Bakoev ◽  
Nikolay Bardukov
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Mixed Model ◽  
Linear Mixed Model ◽  
Fluorescent Dyes ◽  
Dominant Effect ◽  
Swine Industry ◽  
Large White ◽  
Litter Weight ◽  
Litter Traits

Abstract One of the main goals in the swine industry is a finding of significant SNPs associated with Litter traits. Therefore, SNPs localized in SMAD6 (g.164674664G &gt;A) and SUGCT (g.53672799A &gt;G) genes are of great interest. The purpose of this work is optimizing the SNPs genotyping for real-time PCR technology and detection additive and dominant effects on Litter Traits. The research was conducted on Large White breed sows (n = 400). Total number born (TNB), Total number born alive (NBA), Litter weight, piglets born alive (BALWT) were estimated. Associative analysis was performed using the Linear mixed model (LMM) procedure in the R (coded additive effect 0, 1, 2 and dominant effect 0, 1, 0). For the Real-time PCR genotyping we used the TaqMan method, based on the 5`nuclease activity of Taq polymerase, which detaches nucleotides from oligonucleotide probes hybridized with DNA. Two TaqMan probes with different polymorphic sites are needed. These probes have different fluorescent dyes at the 5’ end and fluorescence dampers at the 3’ end. The primers for SNP_g.164674664G &gt;A genotyping: R6G-TGGTCCCCGGGACAGGC-BHQ-1; FAM-TGGTTCCCGGGACAGGC-BHQ-1; F5’-CAAGGTCAGACAAAGGGACTGC-3’; R5’-ACTGTATGTAAAGCATGGTGTAAGC-3’ The primers for SNP_g.53672799A &gt;G genotyping: FAM-CTTCAGCATCTGAACAGAACA-BHQ-1 R6G-CTTCAGCGTCTGAACAGAACA-BHQ-1 F5’-GGAACTGCTATCTGTTTCATTTCTT-3’ R5’-GGAGCTCAAATCCCAGTATTGC-3’. The additive and dominant effects of SNP_g.164674664G &gt;A on Litter weight are determined. Litter weight were 1.8 (12.6%, P &lt; 0.05) and 1.1 (7.7%, P &lt; 0.05) higher in sows of SNP_g.164674664_AA and SNP_g.164674664_AG genotypes respectively. The negative dominant effect SNP_g.53672799_AG is found for TNB and BALWT (Table). Homozygous sows comparing to heterozygous, have higher TNB and BALWT by 0.7 (4.7%, P ≤ 0.05) and 1.0 (7.4%, P ≤ 0.05), respectively. The reported study was funded by RFBR according to the research project № 18-016-00050-A.

Analyzing discontinuities in longitudinal count data: A multilevel generalized linear mixed model.

2020 ◽  
Author(s):  
James L. Peugh ◽  
Sarah J. Beal ◽  
Meghan E. McGrady ◽  
Michael D. Toland ◽  
Constance Mara
Keyword(s):  
Count Data ◽  
Mixed Model ◽  
Linear Mixed Model ◽  
Generalized Linear Mixed Model ◽  
Longitudinal Count Data

Predicting bycatch hotspots based on suitable habitat derived from fishery-independent data

2020 ◽  
Vol 641 ◽  
pp. 159-175
Author(s):  
J Runnebaum ◽  
KR Tanaka ◽  
L Guan ◽  
J Cao ◽  
L O’Brien ◽  
...  
Keyword(s):  
Habitat Suitability ◽  
Mixed Model ◽  
Linear Mixed Model ◽  
Gulf Of Maine ◽  
Homarus Americanus ◽  
Management Tool ◽  
American Lobster ◽  
Suitable Habitat ◽  
Climate Conditions ◽  
Suitability Index

Bycatch remains a global problem in managing sustainable fisheries. A critical aspect of management is understanding the timing and spatial extent of bycatch. Fisheries management often relies on observed bycatch data, which are not always available due to a lack of reporting or observer coverage. Alternatively, analyzing the overlap in suitable habitat for the target and non-target species can provide a spatial management tool to understand where bycatch interactions are likely to occur. Potential bycatch hotspots based on suitable habitat were predicted for cusk Brosme brosme incidentally caught in the Gulf of Maine American lobster Homarus americanus fishery. Data from multiple fisheries-independent surveys were combined in a delta-generalized linear mixed model to generate spatially explicit density estimates for use in an independent habitat suitability index. The habitat suitability indices for American lobster and cusk were then compared to predict potential bycatch hotspot locations. Suitable habitat for American lobster has increased between 1980 and 2013 while suitable habitat for cusk decreased throughout most of the Gulf of Maine, except for Georges Basin and the Great South Channel. The proportion of overlap in suitable habitat varied interannually but decreased slightly in the spring and remained relatively stable in the fall over the time series. As Gulf of Maine temperatures continue to increase, the interactions between American lobster and cusk are predicted to decline as cusk habitat continues to constrict. This framework can contribute to fisheries managers’ understanding of changes in habitat overlap as climate conditions continue to change and alter where bycatch interactions could occur.

Long-term seizure outcomes after pediatric temporal lobectomy: does brain MRI lesion matter?

2019 ◽  
Vol 24 (2) ◽  
pp. 200-208
Author(s):  
Ravindra Arya ◽  
Francesco T. Mangano ◽  
Paul S. Horn ◽  
Sabrina K. Kaul ◽  
Serena K. Kaul ◽  
...  
Keyword(s):  
Repeated Measures ◽  
Mixed Model ◽  
Linear Mixed Model ◽  
Hippocampal Sclerosis ◽  
Brain Mri ◽  
Temporal Lobectomy ◽  
Seizure Freedom ◽  
Seizure Onset

OBJECTIVEThere is emerging data that adults with temporal lobe epilepsy (TLE) without a discrete lesion on brain MRI have surgical outcomes comparable to those with hippocampal sclerosis (HS). However, pediatric TLE is different from its adult counterpart. In this study, the authors investigated if the presence of a potentially epileptogenic lesion on presurgical brain MRI influences the long-term seizure outcomes after pediatric temporal lobectomy.METHODSChildren who underwent temporal lobectomy between 2007 and 2015 and had at least 1 year of seizure outcomes data were identified. These were classified into lesional and MRI-negative groups based on whether an epilepsy-protocol brain MRI showed a lesion sufficiently specific to guide surgical decisions. These patients were also categorized into pure TLE and temporal plus epilepsies based on the neurophysiological localization of the seizure-onset zone. Seizure outcomes at each follow-up visit were incorporated into a repeated-measures generalized linear mixed model (GLMM) with MRI status as a grouping variable. Clinical variables were incorporated into GLMM as covariates.RESULTSOne hundred nine patients (44 females) were included, aged 5 to 21 years, and were classified as lesional (73%), MRI negative (27%), pure TLE (56%), and temporal plus (44%). After a mean follow-up of 3.2 years (range 1.2–8.8 years), 66% of the patients were seizure free for ≥ 1 year at last follow-up. GLMM analysis revealed that lesional patients were more likely to be seizure free over the long term compared to MRI-negative patients for the overall cohort (OR 2.58, p < 0.0001) and for temporal plus epilepsies (OR 1.85, p = 0.0052). The effect of MRI lesion was not significant for pure TLE (OR 2.64, p = 0.0635). Concordance of ictal electroencephalography (OR 3.46, p < 0.0001), magnetoencephalography (OR 4.26, p < 0.0001), and later age of seizure onset (OR 1.05, p = 0.0091) were associated with a higher likelihood of seizure freedom. The most common histological findings included cortical dysplasia types 1B and 2A, HS (40% with dual pathology), and tuberous sclerosis.CONCLUSIONSA lesion on presurgical brain MRI is an important determinant of long-term seizure freedom after pediatric temporal lobectomy. Pediatric TLE is heterogeneous regarding etiologies and organization of seizure-onset zones with many patients qualifying for temporal plus nosology. The presence of an MRI lesion determined seizure outcomes in patients with temporal plus epilepsies. However, pure TLE had comparable surgical seizure outcomes for lesional and MRI-negative groups.

scholarly journals Reducing Aggression by Developing Emotional and Inhibitory Control

2021 ◽  
Vol 18 (10) ◽  
pp. 5263
Author(s):  
Miriam Romero-López ◽  
María Carmen Pichardo ◽  
Ana Justicia-Arráez ◽  
Judit Bembibre-Serrano
Keyword(s):  
Psychosocial Development ◽  
Mixed Model ◽  
Linear Mixed Model ◽  
Generalized Linear Mixed Model ◽  
Emotional Control ◽  
Control Group ◽  
Post Intervention ◽  
Mixed Model Analysis ◽  
Intervention Measures ◽  
Experimental Group

The objective of this study is to measure the effectiveness of a program on improving inhibitory and emotional control among children. In addition, it is assessed whether the improvement of these skills has an effect on the reduction of aggressive behavior in pre-school children. The participants were 100 children, 50 belonging to the control group and 50 to the experimental group, aged between 5 and 6 years. Pre-intervention and post-intervention measures of inhibitory and emotional control (BRIEF-P) and aggression (BASC) were taken. A Generalized Linear Mixed Model analysis (GLMM) was performed and found that children in the experimental group scored higher on inhibitory and emotional control compared to their peers in the control group. In addition, these improvements have an effect on the decrease in aggressiveness. In conclusion, preventive research should have among its priorities the design of such program given their implications for psychosocial development.

scholarly journals Socioeconomic Conditions and Landowners’ Perception Affect the Intention to Restore Polylepis Forests in the Central Andes of Peru

Forests ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 118
Author(s):  
Lunel Joseph ◽  
Raúl Marino Yaranga Cano ◽  
Marco Arizapana-Almonacid ◽  
Marcela Venelli Pyles ◽  
Flávia Freire de Siqueira ◽  
...  
Keyword(s):  
Rural Communities ◽  
Mixed Model ◽  
Linear Mixed Model ◽  
Negative Impact ◽  
Positive Impact ◽  
Central Andes ◽  
Socioeconomic Conditions ◽  
Native Flora ◽  
The Family ◽  
Andes Region

Research Highlights: Families more dependent on crops as the main source of income of properties have a greater intention of restoring Polylepis forest areas. However, this intention reduces with the increase of family dependence on subsistence products supplied by Polylepis forests. Properties where the chances of restoration of Polylepis forests are greater are those where the educational and technical level is better. Objectives: We aimed to comprehend which socioeconomic factors of rural properties and families’ perception were determinant for the intention to restore Polylepis forests in the Central Andes region of Peru. Material and Methods: We collected data through visits and the application of questionnaires. We selected 13 rural communities in the Tulumayo River Basin. We randomly sampled 10 to 20 families in each community, depending on its size, totaling 200 families. We used generalized linear mixed model (GLMM) to test which variables affect the intention to restore the forest. Results: When crops are the main source of income in the property, the families have more intention to restore Polylepis areas, on the other hand, when Polylepis forests are an important source of products for the family subsistence, the intention to restore forests reduces, indicating that higher technological status has a positive impact on restoration. The perception that Polylepis forests are important for the existence of water sources had a positive impact on the families’ intention to restore the areas. However, the perception that Polylepis forests are important for native flora persistence had a negative impact on the intention to restore their areas. Conclusions: Our results showed that investment in improving the productivity of the properties and in the education of their landowners should increase the success of eventual programs for restoration of Polylepis forests.

Sign in / Sign up

Export Citation Format

Share Document