Radical Copolymerization of α‐Trifluoromethylacrylic Acid with Vinylidene Fluoride and Vinylidene Fluoride/Hexafluoropropene

Summary: The radical copolymerization of α‐trifluoromethylacrylic acid (TFMAA) with vinylidene fluoride (VDF), initiated by tert‐butyl 2,2‐dimethyl peroxypropanoate (or tert‐butyl peroxypivalate) is presented. The kinetics of copolymerization were investigated from a series of eight reactions for which the initial [VDF]₀/[TFMAA]₀ molar ratios ranged between 15.0/85.0 and 89.4/10.6. The compositions of the copolymers, i.e. the molar ratios of VDF and TFMAA monomeric units, were determined mainly by ¹⁹F and ¹H NMR spectroscopy. According to the Tidwell and Mortimer method, the reactivity ratios, r_i, were assessed to be: r_VDF = 0.33 ± 0.09 and r_TFMAA = 0 at 55 °C, leading to copolymers of mainly alternating structure. Then, the radical terpolymerization of TFMAA with VDF and hexafluoropropene (HFP), initiated by 2,5‐bis(tert‐butylperoxy)‐2,5‐dimethylhexane is described and the thermal properties of the materials produced are discussed.

     

Acute Effects of Inhaled Urban Particles and Ozone : Lung Morphology, Macrophage Activity, and Plasma Endothelin-1

We studied acute responses of rat lungs to inhalation of urban particulate matter and ozone. Exposure to particles (40 mg/m³ for 4 hours; mass median aerodynamic diameter, 4 to 5 μm; Ottawa urban dust, EHC-93), followed by 20 hours in clean air, did not result in acute lung injury. Nevertheless, inhalation of particles resulted in decreased production of nitric oxide (nitrite) and elevated secretion of macrophage inflammatory protein-2 from lung lavage cells. Inhalation of ozone (0.8 parts per million for 4 hours) resulted in increased neutrophils and protein in lung lavage fluid. Ozone alone also decreased phagocytosis and nitric oxide production and stimulated endothelin-1 secretion by lung lavage cells but did not modify secretion of macrophage inflammatory protein-2. Co-exposure to particles potentiated the ozone-induced septal cellularity in the central acinus but without measurable exacerbation of the ozone-related alveolar neutrophilia and permeability to protein detected by lung lavage. The enhanced septal thickening was associated with elevated production of both macrophage inflammatory protein-2 and endothelin-1 by lung lavage cells. Interestingly, inhalation of urban particulate matter increased the plasma levels of endothelin-1, but this response was not influenced by the synergistic effects of ozone and particles on centriacinar septal tissue changes. This suggests an impact of the distally distributed particulate dose on capillary endothelial production or filtration of the vasoconstrictor. Overall, equivalent patterns of effects were observed after a single exposure or three consecutive daily exposures to the pollutants. The experimental data are consistent with epidemiological evidence for acute pulmonary effects of ozone and respirable particulate matter and suggest a possible mechanism whereby cardiovascular effects may be induced by particle exposure. In a broad sense, acute biological effects of respirable particulate matter from ambient air appear related to paracrine/endocrine disruption mechanisms.     

Use of real-time PCR to process the first galactomannan-positive serum sample in diagnosing invasive aspergillosis

Positive galactomannan (GM) anti-genemias are included as a microbiological item in the diagnosis of probable or possible invasive aspergillosis (IA). Because false-positive GM results frequently occur, at least two positive results on two different samples are required. Waiting for clinical specimens can delay the initiation of treatment. As an alternative, we wondered whether detection of circulating Aspergillus DNA on the first positive GM serum sample could aid in diagnosing IA. Therefore, we retrospectively screened the first GM-positive serum samples from 29 patients from our hematology unit for Aspergillus DNA using real-time PCR. We compared the real-time PCR results with the final classification of proven, probable, and possible IA according to consensual criteria. No clear correlation between PCR results and the classification with the medical files could be shown. However, a positive PCR result was associated with a poor prognosis (Fisher's test; P=0.01). Our preliminary data suggest that a positive PCR result could indicate a more advanced stage of the disease. Therefore, concomitant positive PCR and GM results may justify the initiation of antifungal therapy in neutropenic patients. In contrast, a negative PCR on the first positive GM sample may argue for postponing costly antifungal administration until additional arguments for the diagnosis of IA are presented.     

Instability of characteristics amongst coagulase-negative staphylococci causing endocarditis

Variation in typing of clinically significant isolates of coagulase-negative staphylococci (CNS) was determined by five typing methods with 143 isolates obtained from 19 patients over periods from 2 days to 1 year. In only one case did all isolates give exactly the same typing pattern by all five tests. No single method, or simple combination, provided a ready means of confirming the relatedness of separate isolates. The most frequently useful tests were antibiotic susceptibility and extrachromosomal DNA banding patterns. However, the results of biotyping, serotyping and phage typing were also helpful in showing the relationship between different isolates from a given patient. In most cases a core pattern varying by the gain or loss of a small number of features, characterised a given patient's isolates. In two causes, apparently radical changes in the infecting organism were observed, and confirmed by restriction endonuclease analysis. Care should be taken when successive isolates of CNS show distinct typing differences in deciding their clinical relevance.     

Putative founder effect of Arg338* AP4M1 (SPG50) variant causing severe intellectual disability,epilepsy and spastic paraplegia: Report of three families

Bi-allelic variants affecting one of the four genes encoding the AP4 subunits are responsible for the “AP4 deficiency syndrome.” Core features include hypotonia that progresses to hypertonia and spastic paraplegia, intellectual disability, postnatal microcephaly, epilepsy, and neuroimaging features. Namely, AP4M1 (SPG50) is involved in autosomal recessive spastic paraplegia 50 (MIM#612936). We report on three patients with core features from three unrelated consanguineous families originating from the Middle East. Exome sequencing identified the same homozygous nonsense variant: NM_004722.4(AP4M1):c.1012C>T p.Arg338* (rs146262009). So far, four patients from three other families carrying this homozygous variant have been reported worldwide. We describe their phenotype and compare it to the phenotype of patients with other variants in AP4M1. We construct a shared single-nucleotide polymorphism (SNP) haplotype around AP4M1 in four families and suggest a probable founder effect of Arg338* AP4M1 variant with a common ancestor most likely of Turkish origin.     

Patients’ preferences for sphincter preservation versus abdominoperineal resection for low rectal cancer

BackgroundSurgery for low rectal cancer can be associated with severe bowel dysfunction and impaired quality of life. It is important to determine how patients value the trade-off between anorectal dysfunction versus abdominoperineal resection. Therefore, the objective was to determine patients’ preferences for treatment for low rectal cancer.MethodsAmbulatory patients without colorectal cancer at a single high-volume academic colorectal referral center from September 2019 to March 2020 were included. Patients with prior stoma or malignancy were excluded. Participants were presented with a hypothetic scenario describing a low rectal cancer. A threshold task identified preferences for functional and oncologic outcomes for sphincter preservation versus abdominoperineal resection.ResultsA total of 123 patients were recruited. Patients preferred abdominoperineal resection over sphincter preservation if there were more than a mean of 6.7 (standard deviation 4.0) daily bowel movements, 1.9 (standard deviation 2.6) daily episodes of stool incontinence, and 6.5 (standard deviation 3.2) gas incontinence. Abdominoperineal resection was preferred over sphincter preservation in 38% if daily activities were altered owing to fecal urgency. Patients were willing to accept a 10% (interquartile range, 5?25) absolute increase in risk of margin involvement with sphincter preservation to avoid abdominoperineal resection. Abdominoperineal resection was the preferred option overall for 18% of patients.ConclusionAn important proportion of patients would prefer abdominoperineal resection over sphincter preservation owing to the impairments in anorectal function associated with sphincter preservation. The decision to perform sphincter preservation or abdominoperineal resection should consider how the patients’ value functional outcomes with a low anastomosis.     

The impact of obesity on compensatory mechanisms in response to progressive sagittal malalignment

Background Context

Obesity's impact on standing sagittal alignment remains poorly understood, especially with respect to the role of the lower limbs. Given energetic expenditure in standing, a complete understanding of compensation in obese patients with sagittal malalignment remains relevant.

The “Yes, I Quit” Smoking Cessation Course: Does it Help Women in a Low Income Community Quit?

The objectives were to evaluate the impact of Yes, I Quit (a smoking cessation course tailored for women in a low income, low education community), and to identify baseline predictors of short and longer-term self-reported cessation. The impact was evaluated in a before-after study design with no comparison group. Baseline data were collected in self-administered questionnaires at the beginning of the first session of the course. Follow-up data were collected in telephone interviews at one, three and six months after the designated Quit Day. Self-reported quit rates among 122 participants were 31.1%, 24.7% and 22.3% at one, three and six months. Non-quitters reduced their consumption by 10.3, 8.3, and 7.1 cigarettes per day at one, three and six months. Multivariate logistic regression analyses showed that being in excellent/good health was significantly associated with cessation at one month (odds ratio (OR) = 2.4). Being married (OR = 13.0) and no other smokers in the household (OR = 3.6) were associated with three-month cessation. Only being married was associated with six-month cessation (OR = 6.8). Yes, I Quit produced quit rates among low income, low education participants comparable to those reported for cessation programs directed at the general population of smokers. Good health is associated with early cessation, while support from a spouse is important to maintaining a nonsmoking status among quitters.     

Restriction endonuclease analysis of Staphylococcus epidermidis DNA may be a useful epidemiological marker.

We compared the epidemiological markers of 13 Staphylococcus epidermidis strains isolated from an adult inpatient during a febrile episode and 23 S. epidermidis strains isolated during a presumptive outbreak of nosocomial infection in a neonatal ward. The total DNA restriction endonuclease analysis (REA) was processed along with the following conventional markers: biotyping, serotyping, phage typing, antibiotic susceptibility profiles, and plasmid profiles. The REA method was reproducible, giving stable results both in vitro and in vivo. For the hospitalized adult patient, the conventional markers of the 13 strains were concordant and the restriction profiles were identical. Five restriction groups were demonstrated during the course of the outbreak. Within two of the groups, the identities of all of the markers were used to verify whether all of the isolates belonged to the same cell clone. In a third group, combined analysis of the conventional markers and REA had to be used to demonstrate isolate similarity. On the other hand, in another group, none of the markers were similar; interpretation was not easy. An epidemiological study of S. epidermidis infections in hospitals must take into account all of the epidemiological markers: biotypes, serotypes, phage types, antibiograms, plasmid profiles, and REA.