The Role of Packaging Size on Contamination Rates during Simulated Presentation to a Sterile Field

Objective

The objective of this study was to assess the impact of package size on the contact between medical devices and non-sterile surfaces (i.e. the hands of the practitioner and the outside of the package) during aseptic presentation to a simulated sterile field. Rationale for this objective stems from the decades-long problem of hospital-acquired infections. This work approaches the problem from a unique perspective, namely packaging size.

Design

Randomized complete block design with subsampling.

Setting

Research study conducted at professional conferences for surgical technologists and nursing professionals.

Participants

Ninety-seven healthcare providers, primarily surgical technologists and nurses.

Methods

Participants were gloved and asked to present the contents of six pouches of three different sizes to a simulated sterile field. The exterior of pouches and gloves of participants were coated with a simulated contaminant prior to each opening trial. After presentation to the simulated sterile field, the presence of the contaminant on package contents was recorded as indicative of contact with non-sterile surfaces and analyzed in a binary fashion using a generalized linear mixed model.

Results

Recruited subjects were 26–64 years of age (81 females, 16 males), with 2.5–44 years of professional experience. Results indicated a significant main effect of pouch size on contact rate of package contents (P = 0.0108), whereby larger pouches induced greater rates of contact than smaller pouches (estimates±SEM: 14.7±2.9% vs. 6.0±1.7%, respectively).

Discussion and Conclusion

This study utilized novel methodologies which simulate contamination in aseptic presentation. Results of this work indicate that increased contamination rates are associated with larger pouches when compared to smaller pouches. The results add to a growing body of research which investigate packaging''s role in serving as a pathway for product contamination during aseptic presentation. Future work should investigate other packaging design factors (e.g. material, rigidity, and closure systems) and their role in contamination.     

Single origin of human commensalism in the house sparrow

The current, virtually worldwide distribution of the house sparrow (Passer domesticus) is a result of its commensal relationship with humans. It has been suggested that long before the advent of agriculture, an early glacial advance resulted in two disjunct ranges of ancestral house sparrows - one in the Middle East and another on the Indian subcontinent. Differentiation during this period of isolation resulted in two major groups of subspecies: the domesticus group and the indicus group. According to this hypothesis, commensalism with humans would have evolved independently in the two regions and at least twice. An alternative hypothesis is that morphological differences between the subspecies represent very recent differentiation, following expansions from a single source. To test between these hypotheses, we analysed genetic variation at the mitochondrial DNA control region and at three nuclear loci from several house sparrow populations in Europe, Asia and North Africa. No differentiation between the indicus and domesticus groups was found, supporting the single origin hypothesis. One of the subspecies in the indicus group, P. d. bactrianus, differs ecologically from other house sparrows in being migratory and in preferentially breeding in natural habitat. We suggest that bactrianus represents a relict population of the ancestral, noncommensal house sparrow. When agricultural societies developed in the Middle East about 10 000 years ago, a local house sparrow population of the bactrianus type adapted to the novel environment and eventually became a sedentary, human commensal. As agriculture and human civilizations expanded, house sparrows experienced a correlated and massive expansion in range and numbers. The pattern of genetic variation analysed here is consistent with this scenario.     

Liporotein particles in the jejunal mucosa of fetal rats.

The jejunal mucosa of fetal rats contains particles of the same size, electron density and distribution as particles identified by others in adult jejunum as very low density lipoprotein particles. These particles are first seen in 19-day fetuses at which time the jejunal mucosa is still relatively undifferentiated and formation of villi is just beginning. They become progressively more abundant during the last 3 days of gestation as differentiation proceeds and are seen in virtually all absorptive cells in the apical third of jejunal villi of fetuses at term.     

Renal Carcinogenesis After Uninephrectomy

Nephrectomized rats have widely been used to study chronic renal failure. Interestingly, renal cell carcinoma occurred in the remnant kidney after uninephrectomy (UNX). In this study, we probed insulin-like growth factor (IGF)-1 signaling pathway in UNX-induced renal cancer. Adult male Sprague-Dawley rats were randomized into two groups: UNX rats (n = 22) and sham-operated rats (n = 12). Rats were killed at 3, 7, and 10 months. After 7 months after nephrectomy, the UNX rats developed renal cell carcinoma with increased expression of proliferating cell nuclear antigen, and 68.2% (15/22) of the animals exhibited invasive carcinoma. Western blot demonstrated significant down-regulation of IGF binding protein 3 contrasting with the up-regulation of protein kinase Cζ and Akt/protein kinase B in the renal cancer tissues. These findings indicate a unique rat model of UNX-induced renal cancer associated with enhanced IGF-1 signaling pathway.     

Legacy effects of low N diets on a vernal folivore: deprivation leads to gluttony

We tested for legacy effects of low-N diets offered to newly emerged second-instar spruce budworm (Choristoneura fumiferana) larvae for a duration of either one or two full instars on their growth and nutritional physiology in the sixth instar. The experimental design evaluated the effects of initial diet, final diet, and sex on energy consumption, assimilation, retention, and growth rates. Legacy effects were apparent after two instars of low-N diet exposure and were manifested by elevated ( approximately 10%) consumption rates (RCRs) coupled to elevated ( approximately 10%) growth rates (RGRs) and elevated ( approximately 3%) body energy densities, i.e., heightened fat deposition. However, initial dietary N levels had no legacy main effects on food assimilation efficiencies (ADs), and gross (ECI) and net (ECD) food conversion efficiencies. RCR and AD were dependent on an initial x final diet interaction (i.e., nonlinear legacy effects). RGR depended on an initial diet x sex interaction but not on an initial x final diet interaction. Therefore, the legacy effects of low-N initial diets on RGR and body energy density were simply additive to final diet effects. Final diet universally affected all indices and interacted with sex. Low-N final diets increased RCR ( approximately 41%) and decreased AD (14-18%) but unexpectedly increased ECD (21-24%) and RGR ( approximately 36%). Females generally had higher performance than males on the low-N diets but often only matched males on the high-N diets. Low-N initial diets extended larval development times ( approximately 7-26%) and lowered growth rates (6-24%) to the sixth instar, depending on duration of diet exposure, but did not affect total growth achieved by the start of the sixth instar.     

Application of magnetic techniques in the field of drug discovery and biomedicine

Magnetic separation technology, using magnetic particles, is quick and easy method for sensitive and reliable capture of specific proteins, genetic material and other biomolecules. The technique offers an advantage in terms of subjecting the analyte to very little mechanical stress compared to other methods. Secondly, these methods are non-laborious, cheap and often highly scalable. Moreover, techniques employing magnetism are more amenable to automation and miniaturization. Now that the human genome is sequenced and about 30,000 genes are annotated, the next step is to identify the function of these individual genes, carrying out genotyping studies for allelic variation and SNP analysis, ultimately leading to identification of novel drug targets. In this post-genomic era, technologies based on magnetic separation are becoming an integral part of todays biology laboratory. This article briefly reviews the selected applications of magnetic separation techniques in the field of biotechnology, biomedicine and drug discovery.     

Graft survival and effectiveness of dermal substitution in burns and reconstructive surgery in a one-stage grafting model

Survival of the autograft and objective parameters for scar elasticity were evaluated after dermal substitution for acute burns and reconstructive surgery. The dermal substitute, which was based on bovine type I collagen and elastin-hydrolysate, was evaluated by intraindividual comparison in a clinical trial. The substitute was applied in a one-step procedure in combination with a split-thickness autograft. This treatment was compared with the conventional treatment, the split-thickness antograft. After 1 week, the percentage of autograft survival was assessed. The Cutometer SEM 474 was used to obtain objective measurements of skin elasticity parameters 3 to 4 months postoperatively. Forty-two pairs of wounds (31 patients, age 32.9 +/- 19.3 years; burned surface area, 19.8 +/- 14.5 percent) were treated because of acute burns. Reconstructive surgery was performed on 44 pairs of wounds (31 patients, age 33.9 +/- 17.5 years). Autograft survival was not altered by the substitute for reconstructive wounds, although a slight but significant reduction (p = 0.015) was established in the burn category for substituted compared with nonsubstituted wounds. However, the necessity for regrafting was not increased by substitution. Cutometer measurements of reconstructive wounds with a dermal substitute demonstrated a significant increase of pliability (50 percent, p < 0.001), elasticity (defined as immediate extension, 33 percent, p = 0.04), maximal extension (33 percent, p = 0.002), and immediate retraction (31 percent, p = 0.01), as compared with nonsubstituted wounds. After burn surgery, no improvement was found for the different elasticity parameters. Dermal substitution in a one-stage grafting model seems feasible with respect to graft survival. Skin elasticity was considerably improved by the collagen/elastin dermal substitute after reconstructive surgery.     

Challenges of including human exposure to chemicals in food packaging as a new exposure pathway in life cycle impact assessment

Purpose

Limiting exposure to potentially toxic chemicals in food packaging can lead to environmental impact trade-offs. No available tool, however, considers trade-offs between environmental impacts of packaging systems and exposure to potentially toxic chemicals in food packaging. This study therefore explores the research needs for extending life cycle impact assessment (LCIA) to include exposure to chemicals in food packaging.

Methods

The LCIA framework for human toxicity was extended for the first time to include consumer exposure to chemicals in food packaging through the product intake fraction (PiF) metric. The related exposure pathway was added to LCIA without other modifications to the existing toxicity characterization framework used by USEtox®, i.e., effect factor derivation. The developed method was applied to a high impact polystyrene (HIPS) container case study with the functional unit of providing 1 kg of yogurt in single servings. Various exposure scenarios were considered, including an evidence-based scenario using concentration data and a migration model. Human toxicity impact scores in comparative toxic units (CTU_h) for the use stage were evaluated and then compared to human toxicity impact scores from a conventional LCIA methodology.

Results and discussion

Data allowed toxicity characterization of use stage exposure to only seven chemicals in HIPS out of fourty-four identified. Data required were the initial concentration of chemicals in food packaging, chemical mass transfer from packaging into food, and relevant toxicity information. Toxicity characterization demonstrated that the combined CTU_h for HIPS material acquisition, manufacturing, and disposal stages exceeded the toxicity scores related to consumer exposure to previously estimated concentrations of the seven characterizable chemicals in HIPS, by about two orders of magnitude. The CTU_h associated with consumer exposure became relevant when migration was above 0.1% of the European regulatory levels. Results emphasize missing data for chemical concentrations in food contact materials and a need to expand the current USEtox method for effect factor derivation (e.g., to consider endocrine disruption, mixture toxicity, background exposure, and thresholds when relevant).

Conclusions

An LCIA method was developed to include consumer exposure to chemicals in food packaging. Further study is required to assess realistic scenarios to inform decisions and policies, such as circular economy, which can lead to trade-offs between environmental impacts and potentially toxic chemicals in packaging. To apply the developed method, data regarding occurrence, concentration, and toxicity of chemicals in food packaging are needed. Revisiting the derivation of effect factors in future work could improve the interpretation of human toxicity impact scores.