Antigenic and genetic analysis of a recently isolated H1N1 swine influenza virus.

Hemagglutinins (HA) of H1N1 swine influenza viruses isolated in the United States have remained antigenically and genetically conserved for many years. In contrast to such conservation, the HA of A/Swine/Nebraska/1/92 (Sw/Neb) could readily be distinguished from those of contemporary porcine viruses. Twenty-eight amino acid mutations differentiated the HA of Sw/Neb and A/Swine/Indiana/1726/88, the most recent H1N1 swine influenza virus for which HA sequence data were available. Among these differences were mutations at potential asparagine-linked glycosylation sites and charge changes at many residues. The Sw/Neb virus also could be differentiated from other swine influenza viruses in hemagglutination-inhibition assays with monoclonal antibodies to recent H1 swine HA. Nonetheless, overall sequence analysis of the HA and the nucleoprotein genes of Sw/Neb indicated that this virus was more closely related genetically to classic H1N1 swine influenza viruses than to H1N1 avian or human viruses. Infection of swine with Sw/Neb under experimental conditions induced clinical signs and lesions typical of swine influenza. However, affected swine in the field had high, persistent fevers, but relatively mild signs of respiratory tract disease. This study indicated that an antigenically and genetically novel variant of swine influenza virus was detected in the United States.

Some observations relating to behind-body armour blunt trauma effects caused by ballistic impact.

Live, anesthetised pigs were used to assess behind-armour blunt trauma effects. The thoraco-abdominal body region was covered with varying thicknesses of Kevlar fabric packets. This soft body armour was applied, either in direct contact with the thoracic wall of the animals, or with different plastic foam sheets, so-called trauma packs, between the armour and the skin. The live animals were surgically evaluated, and then sacrificed. Blocks of soft soap were subjected to equal tests and the behind-armour indentations were measured. The results indicate that serious injury to the body armour-protected chest may be caused by the impact of nonpenetrating bullets and shotgun pellets. Severe pulmonary contusions and lacerations were found when the energy transferred through the body armour was estimated to be high.

Intrathoracic pressure variations in an anthropomorphic dummy exposed to air blast, blunt impact, and missiles.

Experiments with an anthropomorphic dummy for blast research demonstrated that pressures recorded in the lung model of the dummy could be correlated to primary air blast effects on the lungs of experimental animals. The results presented here were obtained with a dummy of the type mentioned above, but with the lung model modified to improve geometric similarity to man. Blast experiments were performed in a shock tube, and impact experiments in a special impact machine. Experiments with nonpenetrating missiles were performed with small-caliber firearms and the dummy protected by body armor. Severity indices derived from the blast experiments were related to established criteria for primary lung injury in man. Impacts delivered in the impact machine and by nonpenetrating missiles are compared. Relationships between severity of impact based on experiments with animals and primary lung injury in man are discussed.

Terminal behaviour of deforming bullets.

Some types of deforming bullets, including soft-point hunting ammunition and so-called shotgun slugs, were fired against blocks of soft soap and against the muscular parts of the hind legs of live, anesthetised pigs. The deformation, breakup, and retardation of the bullets within the targets were recorded by means of a multi-flash X-ray setup. The extent of the soft-tissue damage was evaluated by means of debridement performed by a highly skilled surgeon. The excised tissue was then accurately weighed. The potential to transfer energy of these bullets was, as could be anticipated, extremely high, and the injuries caused were very large. The relations between bullet velocity, construction, deformation, breakup, and the resulting injuries are discussed.

Wound ballistics of Swedish 5.56-mm assault rifle AK 5.

The recently adopted Swedish standard 5.56-mm assault rifle Ak 5, with ammunition 5.56-mm sk ptr 5 stkprj, closely similar to the Belgian weapon FNC, with corresponding ammunition SS 109, was fired against blocks of soft soap and against the muscular parts of the hind legs of live, anesthetised pigs. The behaviour and retardation of the bullets within the targets were recorded by means of a stereo, multiflash X-ray setup. The extent of the soft-tissue damage was evaluated in sections by means of debridement performed by a highly skilled surgeon. The excised tissue was then accurately weighed. The energy transfer characteristics and the wounding potential of the weapon are discussed.

A proposed standard methodology for estimating the wounding capacity of small calibre projectiles or other missiles.

A standard methodology for estimating the energy transfer characteristics of small calibre bullets and other fast missiles is proposed, consisting of firings against targets made of soft soap. The target is evaluated by measuring the size of the permanent cavity remaining in it after the shot. The method is very simple to use and does not require access to any sophisticated measuring equipment. It can be applied under all circumstances, even under field conditions. Adequate methods of calibration to ensure good accuracy are suggested. The precision and limitations of the method are discussed.

LOcal effects of antibacterial therapy (benzyl-penicillin) on missile wound infection rate and tissue devitalization when debridement is delayed for twelve hours.

Spherical steel bullets (0.88 g, 6.00 mm in diameter, impact velocity around 1000 m/s, smooth-bore rifle) were used for infliction of trauma to the thigh of pigs. The aim was to find out the effect of early antibiotic therapy (benzyl-penicillin) on wound infection rate and on the local progressive tissue devitalization when debridement was delayed until 12 hours after infliction of trauma. The main study on infection and tissue devitalization contained 20 missile wounds; the pilot study on cell metabolism 13 wounds. In the first group 11 pigs, and in the second group 7 pigs were treated with penicillin. Debridement was performed 12 hours after the infliction of trauma. Bacteriological analyses were done on tissue samples from the wound after pc treatment. The contents of adenosine triphosphate, creatine phosphate, glucose, glucose 6-phosphate and lactate were analysed in tissue samples from the wound with and without pc-treatment 12 h after trauma. The usual growth of bacteria when debridement was delayed for 12 h was totally inhibited by the early provision of penicillin. The amount of devitalized tissue-removed in relation to transferred energy was significantly reduced after the treatment as compared to the non-pc-group. The results of the studies on cell metabolism point to a graded tissue damage and possibly reversible injuries in the periphery of the wound, and to less metabolic disturbances after pc-treatment. The results indicated that early general supply of antibiotics may confine the local tissue injury when delayed debridement is anticipated.

The extent of muscle tissue damage following missile trauma one, six and twelve hours after the infliction of trauma, studied by the current method of debridement.

Spherical missiles with velocities around 1000 m/s were used to inflict missile trauma to one thigh of pigs. The determination of the impact and exit velocities made it possible to calculate the extent of energy transferred to the tissue. About one third of the pigs were treated surgically within one hour after the trauma, one third after a delay of 6 hours and one third after 12 hours. The surgical procedure consisted of debriding muscle tissue which showed impaired contractility and/or consistency and discoloration and/or lack of capillary bleeding - the current criteria of non-viability. The amount of debrided muscle tissue from each wound was weighed and the amount of debrided muscle tissue per joule transferred to the tissue was calculated. As compared to operations performed within one hour the average of the debrided muscle tissue per joule was greater after 6 hours delay and even still greater after 12 hours. However, the difference between the averages after 6 and 12 hours were not statistically significant.

[Tension band wiring of canine and feline supracondylar epiphyseal femoral fractures (author's transl)]. / Osteosutur i "åtta" för behandling av suprakondylära femurfrakturer i epifyslinjen hos hund och katt.

The present investigation describes the treatment of 27 cases of canine and feline supracondylar epiphyseal--metaphyseal femoral fractures with tension band wire. The wire was passed through transversal parallell drill holes, one in each fragment. The wires intercrossed dorsally. Stable fixation followed tightening of the wires. 20 out of 25 primarily successful cases were re-examined. 19 were completely well. One case showed a slight transient lameness following hard exercise.

The extent of tissue damage in missile wounds one and six hours after the infliction of trauma studied by the current method of debridement.

Spherical missiles with velocities around 1000 m/s were used to inflict simultaneously missile trauma to both thighs of pigs. The determination of the impact and exit velocity enabled the extent of energy transferred to the tissues to be calculated. One thigh of each pig was treated surgically within one hour and the other one after a delay of 6 hours after trauma. The surgical procedure consisted of debriding muscle tissue which showed impaired contractility, consistency, discoloration or lack of capillary bleeding--current criteria of non-viability. The amount of debrided muscle tissue at the first operation showed a linear regression versus the extent of energy transfer, whereas after 6 hours no relation could be found between the amount of debrided tissue and energy transfer. There was no significant difference between the amount of debrided tissue per joule of transferred energy when the results of the two operations on each pig were compared.

[Postoperative staphylococcal infection as a late complication following treatment of pseudarthrosis (author's transl)]. / Postoperativ stafylokockinfektion som senkomplikation till behandling av pseudartros.

The study describes a case of postoperative infection following surgery of a humeral pseudarthrosis in a dog. The infection was manifested by fistulas which healed after treatment with different antibacterial drugs, but recurred on six different occasions during a period of twenty months after the operation. Staphylococcus aureus or epidermidis was isolated after aerobic incubation while no microbes were detected after anaerobic incubation. The infection appeared to be localized to a suture of polypropylene. The infection regressed and no more fistulas appeared after this suture had been removed.