An experimentally supported, mathematical explanation of the gas chromatographic elution behaviour of the long-chain carbon members of the homologous series

By substituting the saturated vapour phase tension of the pure normal hydrocarbons described by the Clausius-Clapeyron law into the accepted expression of the specific retention volume (V_g,T), a theoretically coherent and relatively simple mathematical evidence of the elution behaviour of the homologous members has been deduced. It gives exponential retention time dependence on carbon number for isothermal, and nearly equidistant (i.e., approximately linear retention-time dependence on carbon number) elution for linear temperature programmed gas chromatographic runs. The final equations are in close correlation with the experimental results. Special emphasis is placed on the fact that a good approximation—not strict physical laws—have been found.     

Chromosomal changes in bovine papillomavirus type 1-induced Syrian hamster tumors

Bovine papillomavirus type 1 (BPV-1) induced fibrosarcomas in the Syrian hamster were studied cytogenetically by G- and C-banding techniques. All tumor derived cells showed chromosome abnormalities that remained stable during serial tumor transplantations. Cells without chromosome abnormalities found in two cultures were derived from the host animals on account of heterochromatin polymorphisms. In most tumors pseudodiploid cells prevailed, some cells were hypodiploid lacking one or two chromosomes, and one tumor showed two hyperdiploid cell clones with one and three additional chromosomes, respectively. Some of the chromosome abnormalities apparently are nonrandom. Three chromosomes (#1, #4, and #15) were most frequently involved in aberrations.     

Mortality prognostication scores do not predict long-term,health-related quality of life after burn: A burn model system national database study

ObjectiveDespite improved mortality rates after burn injury, many patients face significant long-term physical and psychosocial disabilities. We aimed to determine whether commonly used mortality prognostication scores predict long-term, health-related quality of life after burn injury. By doing so, we might add evidence to support goals of care discussions and facilitate shared decision-making efforts in the hours and days after a life-changing injury.MethodsWe used the multicenter National Institute of Disability, Independent Living and Rehabilitation Research Burn Model System database (1994–2019) to analyze SF-12 physical (PCS) and mental component (MCS) scores among survivors one year after major burn injury. Ninety percent of the observations were randomly assigned to a model development dataset. Multilevel, mixed-effects, linear regression models determined the relationship between revised Baux and Ryan Scores and SF-12 measures. Additionally, we tested a model with disaggregated independent and other covariates easily obtained around the time of index admission: age, sex, race, burn size, inhalation injury. Residuals from the remaining 10% of observations in the validation dataset were examined.ResultsThe analysis included 1606 respondents (median age 42 years, IQR 28–53 years; 70% male). Median burn size was 16% TBSA (IQR 6–30) and 13% of respondents sustained inhalation injury. Higher revised Baux and Ryan Scores and age, burn size, and inhalation injury were significantly correlated with lower PCS, but were not correlated with MCS. Female sex, black race, burn size, and inhalation injury correlated with lower MCS. All models poorly explained the variance in SF-12 scores (adjusted r² 0.01–0.12).ConclusionHigher revised Baux and Ryan Scores negatively correlated with long-term physical health, but not mental health, after burn injury. Regardless, the models poorly explained the variance in SF-12 scores one year after injury. More accurate models are needed to predict long-term, health-related quality of life and support shared decision-making during acute burn care.     

Agreement between proxy- and self-report scores on PROMIS health-related quality of life domains in pediatric burn survivors: a National Institute on Disability,Independent Living,and Rehabilitation Research Burn Model System Study

Quality of Life Research - To examine agreement between pediatric burn survivor self- and caregiver proxy-report on multiple PROMIS domains and examine factors associated with differences between...     

Personal Experiences of Pregnancy and Fertility in Individuals with Spinal Cord Injury

Individuals with spinal cord injuries (SCIs) often face a number of barriers in family planning and pregnancy. These barriers can be structural (i.e. inaccessible health care provider offices and providers unfamiliar with fertility, pregnancy, and SCI) or social (i.e. friends, family, and even providers suggesting that individuals with SCI should not have children), and can affect both men and women. Additionally, much of the information about SCI and pregnancy is from a medical perspective and the psychosocial aspects of pregnancy for individuals with SCI have not been considered. 253 men and women with SCI were asked about the information they received about SCI and pregnancy, where they received this information, and how their SCI affected their family planning. The responses shared in this study can be used to inform individuals who work with people with SCI to better assist their clients or patients who have sustained SCI and are considering pregnancy.     

Testing measurement invariance of the patient-reported outcomes measurement information system pain behaviors score between the US general population sample and a sample of individuals with chronic pain

Purpose

In order to test the difference between group means, the construct measured must have the same meaning for all groups under investigation. This study examined the measurement invariance of responses to the patient-reported outcomes measurement information system (PROMIS) pain behavior (PB) item bank in two samples: the PROMIS calibration sample (Wave 1, N = 426) and a sample recruited from the American Chronic Pain Association (ACPA, N = 750). The ACPA data were collected to increase the number of participants with higher levels of pain.

Methods

Multi-group confirmatory factor analysis (MG-CFA) and two item response theory (IRT)-based differential item functioning (DIF) approaches were employed to evaluate the existence of measurement invariance.

Results

MG-CFA results supported metric invariance of the PROMIS–PB, indicating unstandardized factor loadings with equal across samples. DIF analyses revealed that impact of 6 DIF items was negligible.

Conclusions

Based on the results of both MG-CFA and IRT-based DIF approaches, we recommend retaining the original parameter estimates obtained from the combined samples based on the results of MG-CFA.

     

Exploratory and confirmatory factor analysis of the PROMIS pain quality item bank

Purpose

The assessment of pain sensation and quality is a key component in understanding the experience of individuals with chronic pain. This study evaluated the factor structure of the patient-reported outcome measurement information system (PROMIS) pain quality item bank.

Methods

As part of the PROMIS project, we developed a pool of 37 pain quality items, based on a review of existing pain questionnaires and development of new items. A web-based survey was designed and completed by 845 members of the general population and 967 individuals with different types of chronic pain. Exploratory factor analysis (EFA) was conducted on a random split-half sample of the data to examine the factor structure of the 37 PROMIS pain quality items in the general population and in a chronic pain sample. A confirmatory factor analysis was conducted in the holdout sample.

Results

The EFA of the pain quality items resulted in comparable six-factor solutions for the general and chronic pain samples: (1) pulling/tugging pain; (2) tingling/numbness pain; (3) sharp/stabbing pain; (4) dull/aching pain; (5) pounding/pulsing pain; and (6) affective pain. The confirmatory factor analysis in the holdout sample supported this factor structure.

Conclusions

Further research is needed to evaluate the psychometric characteristics of the derived scales based on their factor scores.     

Antitumoral activity of a sulphur-containing platinum complex with an acidic pH optimum

Platinum complexes are essential tools for cancer treatment despite their toxic side effects. Here we describe a new platinum complex with sulphurs as complexing atoms (thioplatin). PURPOSE: To demonstrate that the antitumoral activity of a new sulphur-containing platinum compound (thioplatin) depends on a slightly acidic pH. METHODS: Platinum uptake by tumour cells and interaction with DNA was determined at slightly acidic or alkaline pH. To demonstrate low in vivo toxicity the effects of thioplatin on body weight, blood urea nitrogen, white blood cell count and the histopathological appearance of small intestines and kidneys were evaluated at doses that displayed antitumoral effects against human small-cell lung cancer and human colorectal cancer xenotransplants in nude mice. RESULTS: The slightly acidic pH optimum of thioplatin was proven by the altered electrophoretic mobility of plasmid DNA, quantitation of the platinum content in the DNA of tumour cells and cytotoxicity studies. Thioplatin displayed antitumoral activity without severe side effects such as weight loss, renal ischaemia, destruction of villi in the small intestine or leukopenia as observed at comparable doses of cisplatin. Furthermore, probably due to its lipophilic nature, thioplatin was taken up readily even by cisplatin-resistant cells. In vivo studies with human tumour xenografts in nude mice showed a therapeutic index of thioplatin five to ten times higher than that of cisplatin.