How thirty years of focused safety development has influenced injury outcome in volvo cars.

ABSTRACT This study points out how thirty years of focused safety development has produced a steady decrease in injury rates in car crashes, strongly influenced by a well-structured process. An important part of this process is the knowledge gained by accident research based on collection of data from real world crashes, and the feedback of this research into development work. Statistical analysis shows that the MAIS 2+ injury rate for the most recent car models has decreased by two-thirds compared to the rate for the oldest car models. Calculation of the effect of specific development steps will be given as examples.

WHIPS--Volvo's Whiplash Protection Study.

Whiplash associated disorders (WAD) resulting from rear end car impacts are an increasing problem. WAD are usually not life threatening, but are one of the most important injury categories with regard to long-term consequences. This paper is a review of Volvo's Whiplash Protection Study (WHIPS), which is the result of more than ten years of concentrated research efforts in the area of neck injuries in car collisions, with the focus on rear end car impacts. The study follows the whole chain from accident research to the development of a seat for increased protection against WAD. Results from Volvo's accident research are summarized. Existing biomechanical knowledge regarding possible injury mechanisms are presented and discussed. Based on the interpretation of accident research and biomechanical knowledge, guidelines for improved protection against WAD in rear end impacts are presented. Requirements and test methods based on the guidelines are explained. An important part of the study is a new rear end impact dummy, BioRID. Test results using the new dummy are presented. Finally, the paper explains the design of a new seat for increased WAD protection, the WHIPS-seat. Results from the accident research and biomechanical research emphasize the importance of considering the whole spine of the occupant and, accordingly, the whole seat when addressing WAD in rear end impacts, with a particular focus on low and moderate impact severity. Low and moderate impact severity crashes should be focused. Also important to consider are the individual differences between occupants, the seating position and the variety of seating postures. All results, including sub-system testing, mathematical modeling, sled testing, as well as geometrical parameters show that the WHIPS-seat will have considerable potential for offering increased protection against WAD in rear end impacts.

Injury severity assessment for car occupants in frontal impacts, using disability scaling.

Injury classification and assessment is one of the most important fields of injury prevention. At present, injury assessment focuses primarily on the risk of fatalities, in spite of the fact that most people who are injured survive the trauma. The net result of a fatality-based approach is that safety and vehicle engineers must make decisions with an incomplete, and sometimes misleading, picture of the traffic safety problem. By applying disability scaling reflecting long-term consequences to injury data, the most significant disabling injuries can be identified. The priorities change with the level of disability used in the scaling. In this study, the risk of permanent medical disability due to different injuries was derived and linked to abbreviated injury scale (AIS) values for 24,087 different injured body regions. This material is based on insurance data. To study how the importance of different bodily injuries changes with different severity assessments in a realistic real-world injury distribution, Swedish insurance industry disability scaling was applied to 3066 cases of belted Volvo drivers involved in frontal collisions. Crash severity was included in the study by using equivalent barrier speed (EBS). When lower levels of disability are included, injuries to the neck and the extremities become the most important, while brain and skull injuries become the most prominent at higher levels of disability. The results presented in this article should be regarded as a contribution to the development of a suitable disability scaling method. The results can also be utilized to further injury research and vehicle design aimed at reducing injuries which have the most important long-term disability consequences.

Correlation of occupant injuries in traffic accidents and dummy responses in mathematical simulations.

This report describes a method of evaluating the real safety of a car or a design feature by correlating data from mathematical simulations and occupant data from accidents. Extensive accident material with a certain car model is used to describe facial injuries for belted drivers in frontal impacts. In a carefully validated model, simulations are carried out at different crash test speeds and for different dummy sizes. The data from the accident material and from the simulations are correlated with special attention to crash severity, occupant size, trajectory, and contact speed.

Rearward-facing child seats--the safest car restraint for children?

During recent years the use of child restraints in cars in Sweden has rapidly increased. The fact that the different restraint systems prevent injuries has been substantiated, as is shown in this paper. The major emphasis is put on the benefits of using rearward-facing child seats for children 0 to 4 years of age. Attitudes concerning child safety in cars and the misuse problem are also discussed. Based on Volvo's accident material it is shown that the injury-reducing effect of the rearward-facing child seat is superior to all present types of child restraints in cars. This paper is mainly based upon Volvo's own traffic accident material. This paper is based upon accidents that occurred between the years 1976 and 1988 and comprises some 13,000 accidents involving approximately 22,000 people. In 1,500 of these accidents at least one child (0 to 14 years) was present in the vehicle. In addition to the collection of accident data, separate attitude studies have been carried out, concerning child safety in cars.

Cellular metabolism of arsenocholine.

The biotransformation of arsenocholine and arsenobetaine, which are organic arsenic compounds present in certain aquatic organisms, has been studied in vitro using synthetic reference substances. Incubation of arsenocholine with different liver cell fractions showed arsenocholine to be biotransformed only in presence of the mitochondrial fraction. The biotransformation products were arsenobetaine aldehyde, arsenobetaine, trimethylarsine oxide and trimethylarsine. Arsenobetaine was the major metabolite and it was formed via arsenobetaine aldehyde. Trimethylarsine oxide was formed via a side reaction from arsenobetaine aldehyde. Further reduction of trimethylarsine oxide, produced trimethylarsine. In vitro studies of arsenobetaine, did not show any formation of trimethylarsine oxide or trimethylarsine. Furthermore, cytotoxicity of arsenobetaine or arsenocholine in isolated hepatocytes was not observed.

Quantitative determination of arsenocholine and acetylarsenocholine in aquatic organisms using pyrolysis and gas chromatography/mass spectrometry.

A method for qualitative and quantitative analysis of trace amounts of quaternary organoarsenicals such as arsenocholine and acetylarsenocholine has been developed. The method is based on pyrolysis, gas chromatography/mass spectrometry and use of deuterium-labelled internal standards. Arsenocholine and acetylarsenocholine have been estimated in fish from arsenic-polluted brackish water and compared with the same species of fish from unpolluted water. The investigation also includes some fish and crustacea from marine water. The presence of arsenocholine and acetylarsenocholine in different aquatic organisms indicate the existence of a general metabolic pathway for these compounds in aquatic ecosystems.

Biotransformation of dimethylarsinic acid in mouse, hamster and man.

The metabolism of dimethylarsinic acid (DMA) a common pesticide and the main metabolite of inorganic arsenic in mammals, has been studied in mice, hamsters and man. Mice and hamsters were administered a single dose of 74As-DMA (40 mg As/kg body weight) orally, while a human subject ingested DMA corresponding to 0.1 mg As/kg body weight. Ion exchange chromatography, paper electrophoresis, thin layer chromatography as well as arsine generation--gas chromatography combined with atomic absorption spectrophotometry or mass spectrometry were used to characterize the arsenic metabolites in urine and feces collected over 48 hours after treatment. In mice and hamsters 3.5% and 6.4% of the dose, respectively, were excreted in urine in the form of trimethylarsine oxide (TMAO). No TMAO was found in feces. A DMA-complex was detected in urine and feces. It amounted to about 13% of the dose in mice and 15% in hamsters. About 80-85% of the dose was eliminated in urine and feces in the form of unmetabolized DMA. No demethylation of DMA to inorganic arsenic was observed. In man, about 4% of the dose was excreted in urine as TMAO and about 80% as DMA.

Identification and quantification of arsenocholine and acetylarsenocholine in trace amounts in biological material by use of pyrolysis gas chromatography/mass spectrometry.

An analytical method, based on a selective extraction and pyrolysis gas chromatography/mass spectrometry assay of arsenocholine and acetylarsenocholine in aquatic organisms, is described. Characteristic fragmentation patterns were obtained from pyrolytically demethylated compounds. The molecules were rearranged in unique pathways which differed from those of corresponding nitrogen analogues. Qualitative determination of arsenocholine and acetylarsenocholine was achieved by gas chromatographic as well as mass spectrometric analysis of the thermal degradation products (trimethylarsine, dimethylvinylarsine and the demethylated arsenocholine or acetylarsenocholine). Arsenocholine and acetylarsenocholine in fish from industrially polluted water were isolated and identified. Massfragmentographic quantification of the arsenic compounds in fish was carried out by use of deuterium labelled analogues of arsenocholine and acetylarsenocholine as internal standards. The method showed a high sensitivity.

Synthesis of 73As-radiolabelled arsenobetaine and arsenocholine for metabolic studies and their fate and distribution in laboratory animals.

73As-labelled arsenobetaine and arsenocholine have been synthesized in mg scales in this laboratory. Specific radioactivities in the range of 100 muCi (3.7 MBq) 73As/mg As have been employed. Further purification of the synthesized compounds has been performed by ion exchange chromatography.

Acetylarsenocholine: a cholinergic agonist.

The pharmacological properties of acetylarsenocholine, an arsenic analogue of acetylcholine, were investigated. Acetylarsenocholine behaved as a cholinergic ligand both in the central and peripheral nervous system. It bound to nicotinic receptors in rat medulla-pons with a KD of 15 microM and to muscarinic receptors in rat cerebral cortex with a KD of 10 microM. It behaved also as an agonist at presynaptic muscarinic receptors in guinea pig ileum myenteric plexus preparation. Arsenocholine is an alternative substrate for choline acetyltransferase and acetylarsenocholine is an alternative substrate for acetylcholinesterase.

A rapid method for the selective analysis of total urinary metabolites of inorganic arsenic.

Total urinary arsenic has traditionally been used for assessing occupational exposure to inorganic arsenic. However, dietary arsenic, especially from seafood, may greatly influence this value. This paper describes a fast and convenient method for routinely measuring the combined amount of inorganic arsenic, methylarsonic acid, and dimethylarsinic acid, which are the major urinary metabolites after exposure to inorganic arsenic. Organic arsenic compounds of marine origin are not biotransformed to inorganic arsenic or methylated arsenic acids to any significance in the human body. They do not produce arsines when treated with the reducing agent in the proposed method and will therefore not interfere with the measurements. The sensitivity, accuracy, and precision of the proposed method are sufficient for the determination of concentrations of arsenic normally found in the urine of nonexposed persons. The method is based on a commercially available hydride generation kit attached to an atomic absorption spectrophotometer.