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Biomedical subjects

Stefan Pollak

Publications and source records attributed to Stefan Pollak.

At least 19 recordsLinked to original sources
PubMed2005

Low-volume amplification on chemically structured chips using the PowerPlex16 DNA amplification kit.

In forensic DNA analysis, improvement of DNA typing technologies has always been an issue. It has been shown that DNA amplification in low volumes is a suitable way to enhance the sensitivity and efficiency of amplification. In this study, DNA amplification was performed on a flat, chemically structured glass slide in 1-microl reaction volumes from cell line DNA contents between 1,000 and 4 pg. On-chip DNA amplification reproducibly yielded full allelic profiles from as little as 32 pg of template DNA. Applicability on the simultaneous amplification of 15 short tandem repeats and of a segment of the Amelogenin gene, which are routinely used in forensic DNA analysis, is shown. The results are compared to conventional in-tube amplification carried out in 25-microl reaction volumes.

Case-Control Studies↗
PubMed2005

Sharp force injuries in clinical forensic medicine--findings in victims and perpetrators.

The injury findings in 58 perpetrators and 158 victims surviving bodily injuries due to sharp force are presented here. Defence injuries were found in 45.9% of the victims without any significant differences between males and females. There was no clear predominance of defence injuries on the left forearm and hand, as is known from autopsy studies; the right and the left hands were affected with an almost identical frequency. Regarding other parts of the victims' bodies, the topographic distribution of injuries showed a marked concentration on the left side (63.7%). The thorax, head and neck were frequently affected (45.9%, 15.3% and 15.3%, respectively), and less often the abdomen (11.1%), the lumbar and gluteal region (6.3%) and the lower extremities (6.1%). In surviving victims with only one singular stab apart from the upper limbs, the incidence of additional defence injuries on the hands and/or forearms was significantly higher (28.3%) than in fatalities. When the perpetrators had unintentionally cut their own hands, the frequency of these injuries on the right and left hands was almost equal.

Adolescent↗
PubMed2004

Cuts to the offender's own hand--unintentional self-infliction in the course of knife attacks.

In a knife attack the perpetrator can unintentionally injure his own hand, if the knife does not have an adequate handguard and the tip of the blade hits a solid, mostly bony structure while being violently thrust into the victim's body. The injuries occurring under these conditions are localized on the flexor side of the knife-holding hand and may include the index, middle, ring and little fingers. They are seen particularly often on the little finger at the level of the proximal phalanx and in the skin fold of the proximal interphalangeal joint. The majority of these cuts run transversely to the longitudinal axis of the fingers and can show a step-like arrangement with different distances to the metacarpophalangeal joints, often from ulnar-proximal to radial-distal. In the six cases presented the injuries were most pronounced on the ulnar side of the hand. When the flexor tendons of the fingers are also severed and the tendon stumps are strongly retracted this indicates that the fist was firmly closed at the time of the injury.

Adolescent↗
PubMed2004

Prevalence of rhabdomyolysis in drug deaths.

Rhabdomyolysis has repeatedly been reported as a possible consequence of illicit drug consumption especially in clinical literature. In order to investigate the prevalence of rhabdomyolysis in cases of drug deaths, immunohistochemical staining of kidney sections with a myoglobin antibody was performed at 103 consecutive fatal drug poisonings. The control group consisted of 107 unselected forensic autopsies. With regard to the presence of intratubular myoglobin, 33% of the study group were categorized as "strongly positive", 17.5% as "slightly positive" and 49.5% as "negative". No single substance showed a particularly high incidence of rhabdomyolysis nor were there correlations to special combinations of substances. In the control group a "strongly positive" result after myoglobin staining was observed in only 10.3% of 107 cases, a "slightly positive" result in 13.1% and a "negative" result in 76.6%. The findings suggest that rhabdomyolysis is a frequent consequence of illicit drug consumption and that it is not promoted by a single factor, but by a combination of several factors.

Adult↗
PubMed2004

Different methods to determine length heteroplasmy within the mitochondrial control region.

The first and second hypervariable regions of the human mitochondrial DNA control region contain two homopolymeric stretches of cytosine (nt 16184-16193 and nt303-315, respectively). According to the Cambridge reference sequence these homopolymeric stretches are interrupted by thymine (T), at positions 16189 and 310, respectively. Monotonous runs of the same base have been suggested to be hot spots for mutations, probably caused by replication slippage, resulting in length heteroplasmy. This paper describes a rapid method based on restriction cleavage of labelled PCR products encompassing the homopolymeric tract in HVII to quantify the relative proportions of different length variants present in an individual. To compare the accuracy of this method, cloned PCR products from several heteroplasmic individuals have been additionally sequenced.

Artifacts↗
PubMed2003

Mitochondrial DNA control region diversity in hairs and body fluids of monozygotic triplets.

Length heteroplasmy of the homopolymeric cytosine stretch in the hypervariable region II of the mitochondrial D-loop was investigated in blood, buccal cells and hair shafts of monozygotic triplets. The proportions of length heteroplasmy were determined by cloning and sequencing of multiple independent clones. Blood and buccal cells showed an accumulation of molecules with one and two insertions of cytosine residues in relation to the Cambridge Reference Sequence (CRS). The results did not show statistically significant differences between blood and buccal cells of one and the same individual and also not between the three monozygotic brothers. In the hair samples a loss of cytosine residues was established in all three monozygotic individuals compared to blood and buccal cells, suggesting that this must be a regular process. Furthermore, the hair shaft samples showed significant differences between the frequencies of 7, 8 or 9 Cs in the poly C region comparing the three individuals (p<0.008) and in addition there were highly significant differences (p<0.0001) when comparing the results for six different hairs of each individual separately. From these results it can be assumed that besides a common genetic bottleneck during embryonic development, a post-embryonic bottleneck seems to exist in each hair follicle.

Adult↗
PubMed2003

Problems associated with the diagnosis of vitality in burned bodies.

The most important signs of vitality in burned bodies are soot deposits in the respiratory tract, the esophagus and the stomach as well as elevated CO-Hb values in the blood. But these findings show only that a person was exposed to fire fumes while alive; they are no indicator for vital heat exposure. As the external findings in burned bodies are often not very conclusive due to postmortem consumption by the fire, the internal findings are all the more important. Macroscopic signs that hot fumes were inhaled may be edematous swelling and vesicular detachment of the mucosa in the pharynx, the larynx and/or the upper section of the esophagus. As histological changes in the respiratory tract soot deposits, vesicular detachment of the epithelium, hyperemia and edema of the tracheal and bronchial mucosa as well as increased secretion of mucus have been described. These findings may partly be absent although the victim was alive during the fire, which can make diagnosis more difficult. Especially in peracute deaths vitality findings are usually sparse. The significance of the macroscopic and histological parameters of vitality was systematically investigated on the basis of our own autopsy material from the years 1996-2002 (88 cases) and compared with the statements found in the literature. In our study material, the vitality parameters were incomplete in 23% of the burned corpses. In 3% of the cases the question whether there was an antemortem heat exposure could not be answered.

Adolescent↗
PubMed2003

Sequence polymorphisms within the human mitochondrial genes MTATP6, MTATP8 and MTND4.

By sequencing the control region of mitochondrial DNA, the majority of human DNA samples can be differentiated. A further increase in differentiation probability may be possible, e.g. by extending the sequenced region to coding regions of the mitochondrial genome. Restriction to those positions that do not result in a change of the amino acids guarantees that the information thus obtained does not refer to phenotypically relevant information. In the present study the sequence data of the mitochondrial genes MTATP6, MTATP8 and MTND4 were collected from 109 subjects and analyzed in order to define variable positions suitable for identification purposes. There were 32 variable base positions among 850 bases studied from MTATPase genes and 1,200 bases of the MTND4 gene showed 28 variable positions. "Hot spots" for base exchanges were found in both regions and one position (position 11,719 in the MTND4 gene) seems to be suitable for SNP investigation for forensic purposes.

DNA, Mitochondrial↗
PubMed2002

Diagnosis of a captive-bolt injury in a skull extremely destroyed by fire.

The authors report on a combined suicide of a 71-year-old farmer who fired a shot to his forehead with a livestock stunner before burning himself. As the fire was fueled by a pile of firewood it burnt for many hours, thus, causing subtotal incineration of the body. The remaining bones were calcined and reduced to a residual mass of only 3 kg. In spite of the extreme destruction, a circular bone defect corresponding to the site where the captive-bolt had entered the skull could be identified in the frontal squama. The example of this suicide is used to illustrate the problems of distinguishing between mechanical and thermal fractures. As expected, the attempted isolation and amplification of both nuclear and mitochondrial DNA for the purpose of identification was not successful.

Abattoirs↗
PubMed2002

Role for reelin in the development of granule cell dispersion in temporal lobe epilepsy.

The reelin signaling pathway plays a crucial role during the development of laminated structures in the mammalian brain. Reelin, which is synthesized and secreted by Cajal-Retzius cells in the marginal zone of the neocortex and hippocampus, is proposed to act as a stop signal for migrating neurons. Here we show that a decreased expression of reelin mRNA by hippocampal Cajal-Retzius cells correlates with the extent of migration defects in the dentate gyrus of patients with temporal lobe epilepsy. These results suggest that reelin is required for normal neuronal lamination in humans, and that deficient reelin expression may be involved in migration defects associated with temporal lobe epilepsy.

Adaptor Proteins, Signal Transducing↗
PubMedDate not supplied

[Fatal thoracic compression after being partially run over by an automobile].

The authors report on a fatal pedestrian accident in which the victim lay on the street and got under a car being run over by one of the front wheels. Both the car driver and the killed pedestrian were strongly alcohol-intoxicated at the time of the accident (2.45 a.m.). After the car had come to a standstill, the pedestrian remained trapped under the car until she was rescued by the fire brigade. On the basis of the autopsy findings and the technical expert opinion it could be reconstructed that the pedestrian's death was not caused by the consequences of being run over by the car, but by the subsequent compression of her thorax in the final accident position.

Accidents, Traffic↗
PubMedDate not supplied

[Injury pattern in fatal automobile accident passengers due to rear-end collisions].

The article reports on the injury pattern seen in fatally wounded car passengers after rear-end collisions on motorways. The study material included 5 rear-end collisions, in which 9 car occupants (5 drivers and 4 front-seat passengers) were killed. The change in velocity (delta v) was above 60 km/h in all the reported cases. The injury pattern showed the following characteristics: extensive soft-tissue traumatization (subcutaneous haematomas, blood-filled pockets, "décollements") not discernible from outside on the back of the trunk, mostly in the lumbosacral region; dorsal serial rib fractures, often combined with fractures of the spine (including the sacrum and the coccyx) and/or the pelvis; ruptures of the aorta at the typical sites of predisposition; ruptures of the liver and spleen (particularly at the visceral surfaces).

Accidents, Traffic↗
PubMedDate not supplied

[Forensic medicine significance of the fluid content of the sphenoid sinuses].

In the forensic literature the opinion is often held that the presence of aqueous liquid in the paranasal sinuses in conjunction with other findings (plume of froth around the mouth and nostrils, emphysema aquosum, Paltauf's spots, increased haemolysis etc.) can be regarded as a sign of drowning. Especially the sphenoid sinus is easily accessible at autopsy; its content can be aspirated from the base of the skull with a cannula. The valency of the liquid content in the sphenoid sinuses was consecutively investigated in 60 deaths by drowning and 157 other deaths. The results showed that in 92% of the deaths by drowning between 1 ml and 4 ml of aqueous fluid could be found in the sphenoid sinuses. However, a positive result was also obtained in 52% of the other cases autopsied, but in the control group the average volume of the aspirate was smaller than in the group of deaths by drowning.

Adolescent↗
PubMedDate not supplied

[Fatal accident with a special automobile].

The authors report on a traffic accident in which the passenger of a Light Four-wheeled Vehicle (Microcar) approved for use by a disabled person was killed after a rear collision with a compact car. The severity of the accident trauma was critically determined by the vehicle's light construction. Consideration is also given to the legal situation regarding registration and driver's license issues.

Accidents, Traffic↗
PubMedDate not supplied

[Contact shot from infantry weapons with a flash-suppressor].

The number of reports on contact shots from firearms with a flash suppressor attached to the muzzle is small. On the basis of a case report (suicidal shot to the forehead with a Kalschnikow AKMS 47 assault rifle) the morphological peculiarities (characteristics soot pattern, relatively small powder cavity and only minor skin tears in the presence of a bony support) are presented and the conclusions to be drawn from the findings regarding the flash-suppressor, the shot distance, the angle of the shot and the way of holding the weapon are discussed.

Adult↗
PubMedDate not supplied

[Injury potential of soft-air pistols].

Report on a case in which an 8-year-old girl was injured on the left anterior thoracic wall by two shots fired by her 14-year-old cousin from a soft-air pistol (replica of mod. 17 make Glock, cal. 6 mm, solid plastic bullets); the projectiles caused two skin lesions, both reaching into the subcutis. The results of our own shooting tests with 2 different soft-air pistols and the injuries seen in our case confirm that soft-air pistols may cause penetrating soft-tissue injuries when fired from a short distance.

Adolescent↗