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Biomedical subjects

P J Knudsen

Publications and source records attributed to P J Knudsen.

At least 19 recordsLinked to original sources
PubMed2001

Mobile autopsy teams in the investigation of war crimes in Kosovo 1999.

On request of the International Criminal Tribunal for the former Yugoslavia (ICTY), the Danish-Swedish forensic teams worked in Kosovo during the summer and the fall of 1999. The teams worked mainly as "mobile teams" at sites with few graves. Only two larger sites were examined. Most of the bodies were buried separately. A few "multiple burial" graves were examined, but no mass graves were encountered. The main purpose of the autopsies was to establish the cause and manner of death. Identification was of less importance, but a majority of the bodies had been identified prior to the autopsy. A total of 308 bodies, mainly males, were examined. The age varied greatly with a mean age of 47 years. The most common cause of death was gun shot wounds and the most common manner of death was homicide.

Adolescent↗
PubMed1999

Hydrophobic thickness of fluid planar monooleylglycerol membranes maximally thinned by inversed micellisation.

A procedure of making membranes of amphiphilic materials at the bottom of a U-shaped flexible plastic tube within an aqueous medium is described. The membranes were made sufficiently large in order for the annulus area to be neglected. Consequently the hydrophobic thickness of the membrane could be measured by a capacitance technique assuming the relative permittivity of the hydrophobic part of the bilayer. Introduction of an AC microvolt technique allowed manufacture of stable thick membranes by quenching the electroconstriction observed when DC electrical potentials in the millivolt range are used. By continuously monitoring the hydrophobic thickness and by use of the AC microvolt technique the membrane-thinning process by chemical means could be studied in isolation because the electroconstriction was quenched. The maximally thinned hydrophobic thickness of a monooleylglycerol membrane measured at 38 degrees C was found to be 25+/-1.2 A. Criteria and argumentation for maximal thinning of the membrane are put forward. A distinction between genuine and modified cholesterol was demonstrated to be possible by the described method.

Journal Article↗
PubMed1997

The destabilizing effect of body armour on military rifle bullets.

Soft body armour is designed to give protection against fragments and some low velocity bullets but is not designed to stop high velocity rifle bullets. Reports have claimed that soft body armour might disturb the stability of bullets that penetrate it, and that this might increase the size of the lesions. The reason for such an effect might be early yaw of the bullet, so we studied the behaviour of bullets which had passed through soft body armour. A 7.62 x 39 mm AK-47 rifle was fired from a permanent stand using full metal jacketed lead core bullets at a range of 30 m. Soft body armour composed for 14 and 28 layers of aramid fibres (Kevlar) was placed at 90 degrees and 60 degrees to the line of fire. Yaw was measured by the shadowgraph technique and a TERMA Doppler radar. A total of ten shots without body armour, and ten shots with each of the two types of body armour at the two angles were used. The results of the shadowgraph and Doppler radar measurements showed a proportional correlation between the two methods of determining the bullet yaw. The semiquantitative approach of the Doppler radar measurement was in agreement with the more concise measurement using the photographic technique. Velocity loss and loss of spin rate from penetrating 14 or 28 ply Kevlar was negligible. We observed induced instability after penetration of 14 and particularly 28 ply Kevlar, dependence of yaw with respect to the number of layers of Kevlar as well as to the angle of the body armour with respect to the line of fire.

Denmark↗
PubMed1996

DNA typing of cellular material on perforating bullets.

DNA typing of cellular debris from perforating bullets was investigated following shooting experiments. A total of 14 perforating gunshots were fired into 9 calves. PCR typing of tissue fragments was done using bovine-specific primers flanking a 247 bp segment within the bovine lactoglobulin gene. Positive amplification results were obtained for all 9 hollow point (HP) and all 5 full metal jacket (FMJ) bullets. In contrast to HP bullets the smooth surfaces of the FMJ bullets did not have visible biological material, which resulted in weaker bands in the DNA analysis compared to HP bullets. Tissue seemed to accumulate at the base of the projectiles. Due to the lack of a suitable marker in bovines, only a species identification was carried out on the DNA from tissue on the bullets. The small amount of DNA extract (up to 5%) required for specification is promising for the successful application of a set of short tandem repeat (STR) systems for individualization in humans. By individualizing tissue on perforating bullets, the bullet and the victim it passed through can be linked. This can assist the investigation of gunshot deaths, especially when several persons are involved in a gun fight.

Animals↗
PubMed1996

Training in wound ballistics: operation exercise at the Defence Medical Training Centre.

The Defence Medical Training Centre has for a number of years been conducting exercises to give Danish National Service (conscript) surgeons and dentists the opportunity to observe and treat gunshot wounds. The exercises are intended to complement the theoretical training given at the Centre, which has been granted permission by the Ministry of Justice to use experimental animals in the training program. The animals used are shot in the abdomen and both thighs and are kept anesthetized during the exercise but, if possible, breathe spontaneously. Assisted ventilation is available at all times. The weapons used are military weapons: a low velocity 9-mm semiautomatic pistol, SIG P210, a medium velocity rifle, US M1 Carbine, and a high velocity rifle, the AK-74. The ammunition used is conventional, full metal jacketed bullets. Having been shot, the animals are given first aid by the participants who play the roles of ordinary soldiers. The animals are then taken to the regimental aid post, where they are attended by a surgeon for the first time. Intravenous tubes, chest tubes, hemostats, etc. are applied, whereupon the animals are transported by military ambulance to the field hospital. There the abdominal wounds are examined by laparotomy and relevant intraabdominal procedures are performed. The leg wounds are treated by debridement along the lines advocated by the Emergency War Surgery-NATO Handbook. This exercise allows the Defence Medical training Centre to teach wound ballistics in a realistic setting. It is hoped that the pupils will never need the skills acquired at the exercise, but, next to going to war or to some of the more violent parts of the world, Operation Exercise is the best preparation for the demands placed on a medical officer.

Animals↗
PubMed1996

New technology in wound ballistics: the Doppler radar.

The feasibility of using Doppler radar to obtain more accurate measurements of velocity and yaw angle of bullets was investigated. Anesthetized pigs were shot at a range of 9-10 meters, and velocity measurements were obtained using Doppler radar and photocells. The data from the two types of equipment was compared. Excellent correspondence was found between the measurements of entry velocities of low, medium, and high velocity bullets, i.e., an average deviation of less than 1% (range 0-2%). Measurements of exit velocities of low and medium velocity bullets corresponded just as well, but measurements of exit velocities of high velocity bullets was complicated in both methods by signal cluttering caused by fragments of tissue released from the exit wound and by the deflection of the bullet. A Doppler radar was used to follow the movements of the bullet, to determine the velocity, and, if possible, to determine when the bullet stabilizes and the exact yaw angles continuously. We were able to design a system in which even small caliber bullets could be followed for 15-20 meters. It was possible to detect yaw even with these small calibers, and the radar was not disturbed by additional equipment. Using Doppler radar to measure velocity offers important benefits--simple set up, minimal risk of damage to equipment by stray bullets, and very good accuracy. The results of measuring yaw angles of bullets are promising, as far as determining the point of stability is concerned, but further work is necessary to be able to measure the angle of yaw exactly.

Animals↗
PubMed1995

Terminal ballistics of 7.62 mm NATO bullets: experiments in ordnance gelatin.

Military rifle bullets are assumed to tumble 180 degrees in the target and end up facing backwards, but intact. It has been claimed, however, that a German version of the 7.62 mm x 51 (7.62 mm NATO) bullet may fragment at ranges up to 100 m. A lack of strength in the jacket, causing it to break at the cannelure when hitting the target at high impact velocity, has been held responsible for this behaviour. The Danish Armed Forces use a 7.62 mm x 51 bullet, produced by Ammunitionsarsenalet (AMA), which is similar in design. Since the legality of this and similar bullets may be questioned in view of the Hague Declaration of 1899, we decided to supplement an investigation of actual fatal cases with an investigation using ordnance gelatin. In order to compare various makes of bullets on an equal basis, they were fired into ordnance gelatin at various ranges and, consequently with various impact velocities. Bullets manufactured by the US Government, Bofors (Sweden), Raufoss (Norway) and AMA were used. The AMA bullet M/75 used previously was found to fragment at ranges up to approx. 100 m, corresponding to impact velocities of approx. 715 m/sec, while all the other 3 types of bullets were intact at ranges down to 2.5 m, corresponding to impact velocities of approx. 810 m/sec. The final prototype of an AMA bullet to answer this criticism proved capable of withstanding fragmentation as well as the foreign makes previously tested. It will enter series production in late 1995.

Firearms↗
PubMed1995

The crash of the Partnair Convair 340/580 in the Skagerrak: traumatological aspects.

In September 1989 an aircraft carrying 55 people crashed into the sea north of Denmark. There was no warning of the crash. The medico-legal investigation of the accident concentrated on finding clues to the cause of the accident, and identifying the victims, all of whom perished. These were found in two groups--31 were immediately recovered from the surface of the sea and 19 were collected from the sea or shore during the following months. The injuries in the two groups differed, indicating that the aircraft broke up in mid-air. One group probably fell into the sea after a free fall, while the other probably remained in the wreckage until hitting the surface. The victims' injuries showed no evidence of fire or explosion. The technical investigators concluded that the aircraft broke up due to a structural failure in the tail.

Accidents, Aviation↗
PubMed1995

The crash of the Partnair Convair 340/580 in the Skagerrak: identification of the deceased.

In 1989, a Norwegian Convair aircraft crashed into the sea near the northwest coast of Jutland. Apparently, the aircraft had disintegrated in midair. On board were 50 passengers and a crew of 5. There were no survivors. Immediately after the crash 31 bodies were found. During the next 10 days, 11 bodies were recovered from the seabed and within the next 6 months, a further 8 bodies were found. Five bodies were never recovered. All the bodies found were positively identified based on personal effects combined with medical and dental findings. Different models for cooperation between the Primary ID-group, who were responsible for the final identification, and the ID-teams, who performed the examination of the bodies, were tested. It was concluded that the fastest and most reliable results were obtained when the ID-teams responsible for the examination of the bodies also took part in the reconciliation sessions.

Accidents, Aviation↗
PubMed1994

The initial yaw of some commonly encountered military rifle bullets.

The yaw angle in flight of high velocity bullets has been discussed for a number of years, due to its contribution to the tumbling of the bullet in the target. Since few unclassified reports of contemporary bullets are available, we investigated the yaw angles of the bullets used in the M16A2, G3, AK-47 and AK-74 rifles by the shadowgraph technique. Our results show that bullets from military rifles tend to stabilize at less than 3 degrees within 25 m, and this angle has been thought to be insignificant in the production of gunshot wounds. Bullets from some modern small calibre high velocity rifles such as the M16A2 and the AK-74 can have quite large yaw angles in their initial flight. The results, which confirm the opinion of contemporary writers, should settle the controversy in this area of wound ballistics.

China↗
PubMed1994

Doppler radar velocity measurements for wound ballistics experiments.

Bullet velocity is a basic parameter in wound ballistics studies. It is usually measured electronically by means of a variety of solid or photoelectric barriers connected to equipment measuring the time elapsing between impulses, enabling the velocity to be calculated. With the advent of Doppler radar velocity measurement of large calibre artillery shells, the use of this equipment for wound ballistics experiments was investigated. Anaesthetized pigs were shot at a range of 9-10 metres and the velocities measured by Doppler radar and photocells were compared. A very good correspondence between the measured entry and exit velocities in low and medium velocity bullets was found, i.e. an average deviation of less than 1% (range 0-2%) between the two types of equipment. In high velocity bullets measurement of entry velocities was just as good, but in both methods measurement of the exit velocity was complicated by the cluttering of signals by fragments of tissue released from the exit wound and the deflection of the bullet, Doppler radar offers important benefits - simple set up, minimal risk of damage of equipment by stray bullets and very good accuracy - and may replace photocells and similar equipment in studies involving low and medium velocity bullets. Measurement of the exit velocity of high velocity bullets is unsatisfactory in both methods, and it is necessary to improve the Doppler radar method in order to measure that as well.

Acceleration↗
PubMed1993

Cytology in ballistics. An experimental investigation of tissue fragments on full metal jacketed bullets using routine cytological techniques.

Particulate matter on bullets may be used to decide which target they have passed through, and tissue fragments are the obvious candidates for study. In order to determine if recognizable tissue fragments could be found on full metal jacketed bullets, 44 such bullets were fired against anesthetized pigs and 36 were recovered. On 4 bullets fragments of tissue could be identified by routine cytological techniques. The procedure should be attempted in selected cases where it is imperative to know if a bullet has passed through tissue.

Animals↗
PubMed1993

Terminal ballistics of the 7.62 mm NATO bullet. Autopsy findings.

The 7.62 mm x 51 military rifle bullet (7.62 mm NATO) as manufactured in Denmark, and in some other countries as well, has been claimed to fragment when fired at ranges encountered in forensic practice. All autopsied cases of death due to this bullet in Denmark since 1975 were investigated by studying autopsy reports and the bullets retrieved by the police. With one exception, all bullets that were found in, or known to have passed through the body, had fragmented. This behaviour is assumed to be due to a lack of strength in the jacket causing it to break at the cannelure when hitting the target at high velocity. The fragments will increase the already sizeable lesions and may leave the body through several separate exit wounds, presenting problems both for the surgeon treating survivors and for the forensic scientists when defining the direction of the shot. The legality of this and similar bullets in view of the Hague Declaration of 1899 may be questioned, and we feel that the bullet should be redesigned. A programme to this end has been initiated by the Danish state owned ammunition factory.

Accidents↗
PubMed1991

The peritoneal elastic lamina.

The structure and extent of the submesothelial elastic tissue of the peritoneum, tentatively termed the peritoneal elastic lamina (lamina elastica peritonei, LEP), was studied in autopsy and biopsy material by light microscopy. The investigation confirms the presence of a well-defined network of elastic fibres just beneath the basement membrane of the visceral and parietal peritoneum in man. The LEP is claimed to be analogous to similar elastic tissue in other serosal cavities, the pleura and the pericardium, as previously described. The LEP may be useful for normal anatomical as well as pathoanatomical investigations.

Elastic Tissue↗
PubMed1990

Hemodialysis-related induction of beta 2-microglobulin synthesis and release by mononuclear phagocytes.

We have investigated beta 2-microglobulin (beta 2M) synthesis and release by blood leukocytes and isolated mononuclear phagocytes. Since beta 2M was discovered to form amyloid fibrils in patients undergoing long term, chronic hemodialysis and monomeric beta 2M levels in plasma of these patients are highly elevated, and since hemodialysis-related factors that increase beta 2M production are unknown, we evaluated beta 2M production by mononuclear phagocytes under a variety of conditions. We utilized a novel enzyme-lined immunoabsorbant assay to quantitate beta 2M release. Adherence of macrophages onto polystyrene or Cuprophan membranes does not induce beta 2M synthesis or release. In contrast, interaction of macrophages with lipopolysaccharide, gamma-interferon, tumor necrosis factor, or interleukin 1 induces synthesis or release. In contrast, interaction of macrophages with lipopolysaccharide, gamma-interferon, tumor necrosis factor, or interleukin 1 induces synthesis and release of beta 2M, indicating that beta 2M synthesis is increased during macrophage activation. Exposing leukocytes or macrophages to changes in osmotic or oncotic pressure induces a rapid release of beta 2M and interleukin 1 into the cellular medium. These results suggest that during hemodialysis, beta 2M production is more likely to result from endotoxin contamination, or osmotic and oncotic changes, rather than direct interaction of mononuclear phagocytes with cellulosic membranes.

Cell Adhesion↗