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Choice of PCR microtube can impact on the success of long-range PCRs

Chua EW, Miller AL, Kennedy MA

Anal Biochem, 2015 May 15;477:115-7.
PMID: 25766577 DOI: 10.1016/j.ab.2015.02.023

We compared four brands of microtubes with respect to their suitability for long-range polymerase chain reactions (PCRs). One of the four brands was found to have an inhibitory effect, decreasing PCR yields. The effect was universal across different PCR or enzyme systems. Increased ultraviolet absorbance suggests leaching of unknown chemical species into PCR mixtures. However, this could not be confirmed by high-performance liquid chromatography-mass spectrometry analysis. Nevertheless, our article demonstrates a clear impact of the choice of microtubes on long-range PCR success. Due consideration should be given to the PCR microtubes when determining optimal reaction conditions for long-range PCR.
Relationship between head growth and neurodevelopmental outcome of Malaysian very low birthweight infants during the 1st year of life

Ong LC, Boo NY, Chandran V, Zamratol SM, Allison L, Teoh SL, et al.

Ann Trop Paediatr, 1997 Sep;17(3):209-16.
PMID: 9425375

A prospective study was carried out to (i) compare head growth patterns of 103 very low birthweight (VLBW, < 1500 g) Malaysian infants and 98 normal birthweight (NBW, 2500- < 4500 g) controls during the 1st year of life; and (ii) examine the relationship between neurodevelopmental outcome at 1 year of age and occipito-frontal head circumferences (OFC) at birth and at 1 year of age in VLBW babies. When compared with those of NBW infants at birth, mid-infancy and 1 year of age, the mean OFC ratios (observed/expected OFC at 50th percentile) of VLBW infants were significantly lower (p < 0.001). Small-for-gestational-age (SGA) VLBW babies had significantly lower mean OFC ratios than their appropriate-for-gestational-age (AGA) VLBW counterparts at birth (p < 0.001), but this difference was no longer seen at mid-infancy or at 1 year of age. Logistic regression analysis showed that abnormal late neonatal cranial ultrasound findings (odds ratio 8.5, 95% confidence interval 4.12-22.07; p < 0.001) and each additional day of oxygen therapy (odds ratio 1.15, 95% confidence interval 1.00-4.45; p = 0.045) were significant risk factors associated with neurodevelopmental disability at 1 year of age, while mean OFC ratios at birth or at 1 year of age were not. Poor postnatal head growth per se did not predict disability, but probably reflected the consequences of "brain injury" as evidenced by abnormal brain scans.
Comparison of morbidities in very low birthweight and normal birthweight infants during the first year of life in a developing country

Boo NY, Ong LC, Lye MS, Chandran V, Teoh SL, Zamratol S, et al.

J Paediatr Child Health, 1996 Oct;32(5):439-44.
PMID: 8933407

OBJECTIVE: To compare the morbidities in the very low birthweight (VLBW; < 1500 g) and normal birthweight (NBW; > or = 2500 g) Malaysian infants during the first year of life.
METHODOLOGY: Prospective observational cohort study of consecutive surviving VLBW infants and randomly sampled NBW infants born in the Kuala Lumpur Maternity Hospital between 1 December 1989 and 31 December 1992. Infants were followed up regularly during the first year of life, after correction for prematurity.
RESULTS: Compared with NBW infants (n = 106), VLBW infants (n = 127) had significantly higher risk of failure to thrive (odds ratio [OR] = 8.0, 95% confidence intervals [CI]: 1.1 to 354.3), wheezing (OR = 3.7, 95% CI: 1.6 to 9.3), rehospitalization (OR = 2.3, 95% CI: 1.1 to 5.0), cerebral palsy (OR = 8.6, 95% CI: 2.0 to 77.6), neurosensory hearing loss (OR = 12.0, 95% CI: 1.7 to 513.6) and visual loss (7.9 vs 0%, P = 0.002). The mean mental developmental index (MDI) and mean psychomotor developmental index (PDI) at 1 year of age were significantly lower among VLBW infants (MDI 99 [SD = 28], PDI 89 [SD = 25]) than NBW infants (MDI 106 [SD = 18], PDI 101 [SD = 18]) (95% CI for difference between means being MDI: -14.1 to -1.7; and PDI: -17.6 to -6.0). Logistic regression analysis showed that among VLBW infants: (i) male sex, Malay ethnicity and bronchopulmonary dysplasia were significant risk factors associated with wheezing; (ii) longer duration of oxygen therapy during the neonatal period, seizures after the post-neonatal period and wheezing were significant risk factors associated with rehospitalization; and (iii) longer duration of oxygen therapy during the neonatal period was a significant risk factor associated with adverse neurodevelopmental outcome during the first year of life.
CONCLUSIONS: Compared with NBW infants, VLBW Malaysian infants had significantly higher risks of physical and neuro-developmental morbidities.
Fulltext Neurodevelopmental outcome of Malaysian very low birth weight infants: predictive value of cranial ultrasound appearances

Ong LC, Boo NY, Chandran V, Zulfiqar A, Zamratol SM, Allison L, et al.

Singapore Med J, 1997 Mar;38(3):108-11.
PMID: 9269376

The aim of the study was to determine the predictive value of cranial ultrasound scans done in the neonatal period for neurodevelopmental outcome of the Malaysian very low birthweight (VLBW, < 1500 grams) infants assessed at 12 months of corrected age. Of the 101 infants studied, 68 (67.3%) were neurodevelopmentally normal at one year of age, 18 (17.8%) had major and 15 (14.9%) had minor neurodevelopmental impairment. Neurodevelopmental outcome was normal in 66/88 (75.0%) infants who did not have severe intraventricular haemorrhage (IVH) or periventricular intraparenchymal echo densities (PVE) in the first week of life, and in 57/73 (78.1%) with uncomplicated scans at discharge. In contrast, 11/13 (84.6%) with parenchymal echo densities or severe intraventricular bleed in the early neonatal period and 17/28 (60.7%) with complicated scans at discharge had adverse sequelae. There was a significant association between lesions seen on cranial ultrasound in the neonatal period and subsequent neurodevelopmental impairment. Late neonatal ultrasound scans appear to be a better predictor of short-term neurodevelopmental outcome than early scans.
Environmental and anthropogenic factors synergistically affect space use of jaguars

Thompson JJ, Morato RG, Niebuhr BB, Alegre VB, Oshima JEF, de Barros AE, et al.

Curr Biol, 2021 Aug 09;31(15):3457-3466.e4.
PMID: 34237270 DOI: 10.1016/j.cub.2021.06.029

Large terrestrial carnivores have undergone some of the largest population declines and range reductions of any species, which is of concern as they can have large effects on ecosystem dynamics and function.1-4 The jaguar (Panthera onca) is the apex predator throughout the majority of the Neotropics; however, its distribution has been reduced by >50% and it survives in increasingly isolated populations.5 Consequently, the range-wide management of the jaguar depends upon maintaining core populations connected through multi-national, transboundary cooperation, which requires understanding the movement ecology and space use of jaguars throughout their range.6-8 Using GPS telemetry data for 111 jaguars from 13 ecoregions within the four biomes that constitute the majority of jaguar habitat, we examined the landscape-level environmental and anthropogenic factors related to jaguar home range size and movement parameters. Home range size decreased with increasing net productivity and forest cover and increased with increasing road density. Speed decreased with increasing forest cover with no sexual differences, while males had more directional movements, but tortuosity in movements was not related to any landscape factors. We demonstrated a synergistic relationship between landscape-scale environmental and anthropogenic factors and jaguars' spatial needs, which has applications to the conservation strategy for the species throughout the Neotropics. Using large-scale collaboration, we overcame limitations from small sample sizes typical in large carnivore research to provide a mechanism to evaluate habitat quality for jaguars and an inferential modeling framework adaptable to the conservation of other large terrestrial carnivores.
A global-scale screening of non-native aquatic organisms to identify potentially invasive species under current and future climate conditions

Vilizzi L, Copp GH, Hill JE, Adamovich B, Aislabie L, Akin D, et al.

Sci Total Environ, 2021 Sep 20;788:147868.
PMID: 34134389 DOI: 10.1016/j.scitotenv.2021.147868

The threat posed by invasive non-native species worldwide requires a global approach to identify which introduced species are likely to pose an elevated risk of impact to native species and ecosystems. To inform policy, stakeholders and management decisions on global threats to aquatic ecosystems, 195 assessors representing 120 risk assessment areas across all six inhabited continents screened 819 non-native species from 15 groups of aquatic organisms (freshwater, brackish, marine plants and animals) using the Aquatic Species Invasiveness Screening Kit. This multi-lingual decision-support tool for the risk screening of aquatic organisms provides assessors with risk scores for a species under current and future climate change conditions that, following a statistically based calibration, permits the accurate classification of species into high-, medium- and low-risk categories under current and predicted climate conditions. The 1730 screenings undertaken encompassed wide geographical areas (regions, political entities, parts thereof, water bodies, river basins, lake drainage basins, and marine regions), which permitted thresholds to be identified for almost all aquatic organismal groups screened as well as for tropical, temperate and continental climate classes, and for tropical and temperate marine ecoregions. In total, 33 species were identified as posing a 'very high risk' of being or becoming invasive, and the scores of several of these species under current climate increased under future climate conditions, primarily due to their wide thermal tolerances. The risk thresholds determined for taxonomic groups and climate zones provide a basis against which area-specific or climate-based calibrated thresholds may be interpreted. In turn, the risk rankings help decision-makers identify which species require an immediate 'rapid' management action (e.g. eradication, control) to avoid or mitigate adverse impacts, which require a full risk assessment, and which are to be restricted or banned with regard to importation and/or sale as ornamental or aquarium/fishery enhancement.