Non-fatal injuries sustained by seatbelt wearers: a comparative study.

The injuries sustained by 969 drivers and front-seat passengers in road-traffic accidents were studied. Altogether 196 (20-2%) of the drivers and passengers were wearing seat belts and 773 (79-8%) were not. The injuries among the two groups differed greatly in both severity and distribution. A total of 54 (27-6%) of the seatbelt wearers sustained one or more fractures compared with 300 (38-8%) of the non-wearers, and 18 (9-2%) of the seatbelt wearers were severely injured compared with 300 (38-8%) of the non-wearers. Soft-tissue injuries to the face were sustained by only 29 (14-8%) of the seatbelt wearers compared with 425 (55%) of the non-wearers. Since wearing seatbelts may become compulsory, the type and pattern of injuries to be expected in wearers should be appreciated.     

Effect of seat belts on injuries to front and rear seat passengers.

Data on 2520 occupants of cars involved in accidents were analysed in relation to injury and the severity of the crash to investigate the effect of rear seat passengers on injury to restrained and unrestrained front seat occupants and vice versa. Unrestrained front seat occupants showed a higher incidence of serious injury when there were rear seat passengers. The presence of a rear seat passenger did not affect significantly the overall incidence of injury among restrained front seat occupants within the range of crash severity considered. Unrestrained rear seat passengers behind unrestrained front seat occupants showed a higher incidence of moderate injury and a lower incidence of no injury than those behind restrained front seat occupants. It is concluded that legislation on seat belts has not greatly increased the risk of person to person injury.     

Local muscle blood flow and sustained contractions of human arm and back muscles.

The endurance during sustained contraction of elbow, flexors, elbow extensors, and back extensors was tested in 3 human subjects. The force level used was varied between ca. 15 and ca. 75% of maximal isometric strength (IS). The clearance of 133Xe from contracting muscles was registered during and after the endurance test. In this way it was possible to determine whether muscle blood flow (MBF) was increased or had stopped during the contraction. Experiments with artificial ischaemia of the upper arm together with MBF measurements showed that MBF was of no importance for continuing sustained contractions above a certain force level, which was 50,25, and 40% of IS for elbow flexors, elbow extensors and back extensors, respectively. However, the level, where longer lasting ( greater than 15 min) sustained contraction is possible is directly related to MBF. These levels were 22, 15, and 20% IS for elbow flexors, elbow extensors, and back extensors, respectively.     

Report on injuries sustained by patients treated at the Birmingham General Hospital following the recent bomb explosions.

As a result of recent bomb explosions a total of 82 patients were treated at the Birmingham General Hospital, 61 with minor injuries. Bomb injuries may be divided into three main groups due to the blast effect (such as blast lung and ruptured tympanic membranes), the flash (such as burns to the exposed part of the body), and shrapnel (which may cause a wide variety of injuries). The amount of warning of such explosions is usually minimal, and so the prepared accident schemes of most hospitals are inappropriate. If the disaster occurs outside normal working hours much responsibility initially falls on the resident staff. This report gives some idea of the type of injuries they are likely to see.     

Infection by Wolbachia: from passengers to residents

Wolbachia are endosymbiotic alpha-proteobacteria harboured by terrestrial arthropods and filarial nematodes, where they are maternally transmitted through egg cytoplasm. According to the host group, Wolbachia have developed two contrasting symbiotic strategies. In arthropods, symbiosis is secondary (i.e. facultative), and Wolbachia insure their transmission as reproduction parasites. However, despite of the efficiency of the manipulation mechanisms used, Wolbachia are limited to the state of passenger because some factors can prevent the association between Wolbachia and their hosts to become permanent. On the contrary, symbiosis is primary (i.e. obligatory) in filarial nematodes where Wolbachia insure their transmission via a mutualistic relationship, leading them to become permanent residents of their hosts. However, a few examples show that in arthropods too some Wolbachia have started to present the first stages of a mutualistic behaviour, or are even truly indispensable to their host. Whatever its strategy, Wolbachia infection is a spectacular evolutionary success, this symbiotic bacterium representing one of the most important biomass of its kind. To cite this article: H. Merçot, D. Poinsot, C. R. Biologies 332 (2009).     

The transmission of translational seat vibration to the head--II. Horizontal seat vibration

The second part of this study of the six axes of head motion caused by translational seat vibration is concerned with the effect of fore-and-aft (x-axis) and lateral (y-axis) seat vibration. Seat-to-head transmissibilities have been determined at frequencies up to 16 Hz for each of the three translational and three rotational axes of the head during exposure to random vibration of the seat. Repeatability measures within a single subject and studies of the variability across a group of twelve subjects have been conducted with two seating conditions: a rigid seat with a backrest, and the same seat with no backrest. Fore-and-aft seat motion mainly resulted in head motion within the mid-sagittal plane (x-z plane). Without the backrest, transmissibilities for the fore-and-aft, vertical and pitch axes of the head were greatest at about 2 Hz. The backrest greatly increased head vibration at frequencies above 4 Hz and caused a second peak in the transmissibility curves at about 6 to 8 Hz. Lateral seat motion mainly caused lateral head motion with a maximum transmissibility at about 2 Hz. The backrest had little effect on the transmission of lateral vibration to the head. For both axes of excitation inter-subject variability was much greater than intra-subject variability.     

The transmission of translational seat vibration to the head--I. Vertical seat vibration

Vibration in the three translational (fore-and-aft, lateral and vertical) and the three rotational (roll, pitch and yaw) axes of the head has been measured during exposure to whole-body random vibration. Using an instrumented bar gripped between the teeth, the influence of variations in bite grip and bite-bar mass on movements of the head were found to be small up to a mass of 375 g. The repeatability of measures of seat-to-head transmissibility within a single subject and the variability in transmissibility across a group of twelve subjects have been determined with two seating conditions: a rigid seat with a backrest and the same seat with no backrest. Seat-to-head transmissibilities associated with vertical seat vibration are presented at frequencies up to 25 Hz for all six axes of head vibration both with and without a backrest. Head motion occurred principally in the fore-and-aft, vertical and pitch axes of the head. The backrest increased the magnitude of head vibration in most cases. Intra-subject variability was generally small compared to inter-subject variability.     

Use of automobile seat restraints by children in two Canadian cities.

A telephone survey was conducted in Montreal and Calgary to determine the extent to which parents use safety restraints for their children in cars, the types of restraints used and the factors associated with such use. Of the combined sample 39% reported that their child regularly used a restraint, and 47% of the children in Montreal and 55% of those in Calgary wore an age-appropriate safety device. Birth order and the child''s and the respondent''s ages were significantly related to the use of restraints. However, the respondent''s use of seatbelts was the factor most likely to affect the rate of use of restraints for children. Although a large proportion of the parents with younger children owned a carseat, one in four did not use it regularly. Parents who did not use carseats believed they were useless or dangerous; many preferred to hold the child in their laps or arms. The seatbelt law in Quebec and the existence of a carseat rental program in Calgary appear to have had some influence on the rate of the use of restraints for children.