Baby in the bathwater: Should we abandon the use of body temperature thresholds to quantify expression of torpor?

Boyles et al. (this issue) argue against the use of body temperature (T_b) thresholds to quantify the expression of torpor in endotherms and our purpose is to provide a counterpoint argument. We contend that T_b thresholds provide valuable information about ecological factors influencing the evolution of thermoregulation. We also point out shortcomings of the so-called heterothermy index proposed as an alternative. However, to be clear, we do agree with Boyles et al. (this issue) that the use of torpor thresholds can limit some aspects of the study of thermoregulation and applaud the more widespread incorporation of theoretical underpinnings proposed by Boyles et al. (this issue) and others.     

Should we use closed or open infusion containers for prevention of bloodstream infections?

Background

Chronic lung infection with the bacterium Pseudomonas aeruginosa is one of the hallmarks of cystic fibrosis (CF) and is associated with worsening lung function, increased hospitalisation and reduced life expectancy. A virulent clonal strain of P. aeruginosa (Australian epidemic strain I; AES-I) has been found to be widespread in CF patients in eastern Australia.

Methods

Suppression subtractive hybridization (SSH) was employed to identify genetic sequences that are present in the AES-I strain but absent from the sequenced reference strain PAO1. We used PCR to evaluate the distribution of several of the AES-I loci amongst a collection of 188 P. aeruginosa isolates which was comprised of 35 AES-I isolates (as determined by PFGE), 78 non-AES-I CF isolates including other epidemic CF strains as well as 69 P. aeruginosa isolates from other clinical and environmental sources.

Results

We have identified a unique AES-I genetic locus that is present in all 35 AES-I isolates tested and not present in any of the other 153 P. aeruginosa strains examined. We have used this unique AES-I locus to develop a diagnostic PCR and a real-time PCR assay to detect the presence of P. aeruginosa and AES-I in patient sputum samples.

Conclusions

We have developed diagnostic PCR assays that are 100% sensitive and 100% specific for the P. aeruginosa strain AES-I. We have also shown that Whatman FTA^® Elute cards may be used with PCR-based assays to rapidly detect the presence of P. aeruginosa strains in CF sputum.     

Should the Same Safety Scrutiny of Antiobesity Medications be Applied to Other Chronic Usage Drugs?

Obesity treatment is highly stigmatized, mainly because of the stigma of obesity itself. The frequent withdrawal of medications, lorcaserin being the last example, contributes to this stigma, but it is also probably a reflection of it, as data suggest that the threshold for a withdrawal is lower than with other classes of drugs. Safety should always be an absolute priority for every new medication, especially when used on a chronic basis; however, the safety scrutiny given to antiobesity medications is not given for other medications, such as postmenopausal hormone therapy and central nervous system drugs for psychiatric use. The withdrawal of medications for obesity can also impact future research in the area, so we need transparency and equality. Transparency in knowing exactly what reason led to a drug being discontinued and equality in long‐term safety should be a concern with any medication prescribed for chronic diseases.     

Should we expect substitution rate to depend on population size?

The rate of nucleotide substitution is generally believed to be a decreasing function of effective population size, at least for nonsynonymous substitutions. This view was originally based on consideration of slightly deleterious mutations with a fixed distribution of selection coefficients. A realistic model must include the occurrence and fixation of some advantageous mutations that compensate for the loss of fitness due to deleterious substitutions. Some such models, such as so-called "fixed" models, also predict a population size effect on substitution rate. An alternative model, presented here, predicts the near absence of a population size effect on substitution rate. This model is based on concave log-fitness functions and a fixed distribution of mutational effects on the selectively important trait. Simulations of an instance of the model confirm the approximate insensitivity of the substitution rate to population size. Although much experimental evidence has been claimed to support the existence of a population size effect, the body of evidence as a whole is equivocal, and much of the evidence that is supposed to demonstrate such an effect would also suggest that it is very small. Perhaps the proposed model applies well to some genes and not so well to others, and genes therefore vary with regard to the population size effect.     

Should we abandon Kielland's forceps?

To assess the risks associated with the use of Kielland''s forceps 2708 consecutive deliveries were studied prospectively and the neonatal outcome related to the mode of delivery. Of the 1191 primigravidas, 279 (23.4%) underwent instrumental delivery, of whom 65 (5.5%) were delivered with Kielland''s forceps. There was no difference in early neonatal outcome (as judged by Apgar scores, intubations, and admission to the special care baby unit) between these babies and those delivered normally or by non-rotational forceps, but a higher proportion of the 127 (10.7%) delivered by emergency caesarean section were compromised. Of the 1517 multigravid patients, only 57 (3.8%) underwent instrumental delivery, 15 (1.0%) by Kielland''s forceps. Among these babies, also, the outcome was no worse than for those delivered normally, but the babies delivered by caesarean section showed a greatly increased incidence of low Apgar scores, intubations, and admission to the special care baby unit. There were no stillbirths or neonatal deaths among babies delivered by Kielland''s forceps, nor were there any cases of severe birth trauma or of obvious neonatal morbidity.     

Should we expand the indications for analysis of fetal chromosomes?

The usual indications of amniocentesis for prenatal diagnosis are briefly reviewed. Some situations which are note included in these usual indications are discussed: mothers of 34 years, young aunts of a trisomic child, patients with a previous aborted conceptus diagnosed as trisomic by histological examination of the placenta or tissue culture. It is anticipated that, if accepted, these "unusual" criteria would not overload a given laboratory with an excess of analysis, and would certainly relief anxiety of motivated couples.     

Influencing relatives to respect donor autonomy: Should we nudge families to consent to organ donation?

Refusing consent to organ donation remains unacceptably high, and improving consent rates from family or next‐of‐kin is an important step to procuring more organs for solid organ transplantation in countries where this approval is sought. We have thus far failed to translate fully our limited understanding of why families refuse permission into successful strategies targeting consent in the setting of deceased organ donation, primarily because our interventions fail to target underlying cognitive obstacles. Novel interventions to overcome these hurdles, incorporating an understanding of cognitive psychology and behavioral change therapy, may be beneficial. One potential intervention is to use the concept of nudge theory, where decision‐making is influenced by encouraging positive reinforcement and indirect suggestion. Purposefully nudging families to given consent for organ donation by understanding, and then overcoming, their inherent cognitive biases is novel but also controversial. This article explores the roles of relatives in decisions about organ donation, how nudge theory translates to organ donation and discusses the arguments for and against its application.     

Should the use of DDT be revived for malaria vector control?

Indoor residual spraying with DDT was the principle method by which malaria transmission was eradicated or greatly reduced in many countries between the late 1940s and 1970s. Since then, decreasing use of DDT has been associated with a resurgence of malaria in India, Sri Lanka, former Soviet Central Asia, Zanzibar, Venezuela and several other Latin American countries. In India and Zanzibar, DDT resistance in vectors, as well as a decline in spray coverage, are probable causes of reduced effectiveness of DDT in recent decades. In southern Europe, eradication of malaria transmission was achieved by DDT spraying in the 1940s and 50s and eradication has been sustained by adequate treatment of imported human malaria cases. In the highlands of Madagascar and South Africa, recent reversion to DDT spraying has been successful in stemming resurgences of malaria. Continued use of DDT for vector control, but not for agriculture, is approved by the Stockholm Convention on Persistent Organic Pollutants. DDE residues in breast milk have been associated with DDT anti-malaria spraying in South Africa, but it is not known whether this is harmful. A claimed association of DDE residues with breast cancer have not been substantiated. There is a recent report of association of DDE residues with probability of premature birth; the possible relevance of this to anti-malarial use of DDT should be investigated. In Colombia, testing of the DDT stockpile for suspensibility, DDT resistance in Anopheles darlingi and investigation of the present affordability of widespread spraying with DDT, compared with alternative chemicals, are recommended.