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Biomedical subjects

D Sweet

Publications and source records attributed to D Sweet.

At least 19 recordsLinked to original sources
PubMed2000

Anatomical location of bitemarks and associated findings in 101 cases from the United States.

The purpose of this paper is to update and confirm previous studies that examined the anatomical location of human bitemarks. This information is useful to forensic odontologists and pathologists, physicians, and coroners who must be familiar with the most likely locations of bitemarks. The data are also useful for those involved in bitemark research. Using the legal database "Lexis," 101 bitemark cases were identified from the United States Courts of Appeal. Cases were included in the study if they provided details concerning the bitemark, such as anatomical location, number of injuries, and information concerning the victim. Information on 148 bites was collated. These data are presented in tabular and graphical form to allow comparisons between males and females, victims and perpetrators, adults and children, and the crime types associated with human bites.

Adolescent↗
PubMed1999

Saliva from cheese bite yields DNA profile of burglar: a case report.

Physical evidence in the form of a high quality bite mark was discovered on a piece of yellow cheese found at the scene of a crime. The cheese had been frozen by police for 10 days after recovery and before submission to the laboratory for testing. The double swab technique was used to collect DNA samples. A sample of the suspect's blood was obtained. Using PCR-based DNA typing at ten STR loci, (Profiler Plus, Perkin Elmer-Applied Biosystems) it was determined that the DNA from the cheese originated from the suspect. This case illustrates the importance of a) always considering human bite marks as both physical and biological evidence, and b) attempting DNA recovery in any case in which minute traces of saliva may be present, even in situations involving bacteria-rich foods.

Cheese↗
PubMed1999

Microbial fusion.

Explore the source record for details and available documents.

Bacterial Adhesion↗
PubMed1999

Potential for fraudulent use of digital radiography.

BACKGROUND: Digital radiographic images can be manipulated using personal computers. To test the potential for fraudulent use, the authors altered a series of dental radiographs, printed them to simulate duplicated films and submitted them for authorization of proposed treatment. MATERIALS AND METHODS: The authors obtained periapical radiographs of teeth that contained small restorations or were unrestored from the files of three dental patients at a private dental practice. The authors used a flatbed scanner to digitize and import the radiographs into a computer. Then they added dental caries, large restorations, fractures and periapical pathosis to the radiographs. The authors proposed to the insurance companies that the teeth in question be restored using expensive treatment, such as root-canal therapy and full-coverage crowns. RESULTS: In each case, the insurance companies authorized the proposed treatment based on the appearance of the teeth on the radiographs. The altered images illustrated an apparent need for dental treatment that was not required and that could have led to payment for treatment that was not actually performed. CONCLUSIONS: This study illustrates the potential for the fraudulent use of manipulated digital radiographic images. CLINICAL IMPLICATIONS: Dentistry should be aware of the implications of the potential for such abuse and should develop measures both to prevent it from occurring and to facilitate its detection.

Computer Security↗
PubMed1999

Identification of a skeleton using DNA from teeth and a PAP smear.

Identification of unknown living or deceased persons using dental treatment records is an established forensic technique. However, some cases remain unidentified, especially when antemortem dental records are not available for comparison to postmortem dental records. Cytological smears have been previously reported to be potential sources of DNA reference samples which can be compared to DNA recovered from found human remains. The case described here involves an adult skeleton which exhibited extensive, complex dental restorative treatment. A putative identification of the found skeleton as a missing woman was established using circumstantial evidence found at the scene. However, it became important to establish a positive identification using reliable scientific methods. When it was discovered that antemortem dental records were not available because the treatment was completed in another country and the treating dentist could not be found, cytological smears stained with Papanicolaou (PAP) stain obtained from the putative decedent's medical records were used as a reference DNA sample. DNA was recovered from the teeth of the skeleton using cryogenic grinding. Comparison of the genotypes resulted in the conclusion that the DNA originated from the same source. The use of PAP smears in this way is seen as a valuable resource in cases where positive identification using traditional dental and medical records is not possible.

Adult↗
PubMed1999

Analysis of salivary DNA evidence from a bite mark on a body submerged in water.

A female body was recovered after approximately 5.5 h in a river with slow-moving current. On the victim's right breast, a patterned injury was discovered and determined to be from human adult teeth. Evidence was collected according to established techniques including recovery of saliva from the bite mark area despite the body being found submerged in water. DNA analysis by PCR using polymorphic STR markers revealed a DNA profile of mixed origin. In addition to the victim's DNA profile, a genotype contribution from the perpetrator was identified as a minor component. The DNA typing results from the bite mark correlated with the DNA typing results obtained from other biological trace evidence identified from the victim's genital samples. The bite mark and the DNA evidence were used to screen suspects and played an important role in obtaining resolution of this case. Consequently, it is advisable that investigators routinely swab for salivary DNA in bite mark cases, even when the amount is thought to be minimal.

Adolescent↗
PubMed1998

Disseminated neonatal Trichosporon beigelii infection: successful treatment with liposomal amphotericin B.

Trichosporon beigelii, normally a low grade pathogen, can cause disseminated infection in neonates with a high associated mortality. We report a case in a 25-week gestation, 950 g female infant who had evidence of disseminated infection yet survived after treatment with the Liposomal form of Amphotericin B without any evidence of drug-induced adverse effects. A review of previous reported cases shows this form of disseminated mycosis to be rare and almost always fatal.

Amphotericin B↗
PubMed1998

Accuracy of bite mark overlays: a comparison of five common methods to produce exemplars from a suspect's dentition.

Physical comparison of a suspect's teeth to a bite mark injury using hollow volume comparison overlays is a common forensic odontology technique. Several methods are used to record characteristics of the size, shape and position of the teeth and to generate overlays. These include computer-based, radiographic, xerographic and hand-traced methods. Five common overlay production methods were compared using digital images of dental study casts as a reference standard. Area of the biting edges of the anterior teeth and relative rotation of each anterior tooth were measured and compared. The computer-based production method was determined to be the most accurate of those studied. It produced accurate representations of the biting edges of the teeth in an objective manner. The radiographic method was determined to be more accurate than the xerographic method with respect to tooth area measurement. The opposite is true with respect to tooth rotation. Hand-traced methods, from either wax impressions of teeth or directly from study casts, were determined to be inaccurate and subjective. It is recommended that forensic odontologists discontinue the use of hand-traced overlays in bite mark comparison cases.

Bites, Human↗
PubMed1998

Computer-based production of bite mark comparison overlays.

Bite mark comparison protocols include measurement and analysis of the pattern, size, and shape of teeth against similar characteristics observed in an injury on skin or a mark on an object. The physical comparison of tooth position often depends upon transparent acetate overlays to detect similarities or differences between the teeth and the bite mark. Several methods are used to produce life-sized comparison overlays. The perimeter of the biting edges of the anterior teeth are usually recorded to produce facsimile images called hollow volume overlays. Some investigators hand-trace these outlines from dental study casts, or from bite exemplars produced in wax, styrofoam, or similar materials. Some use hand-traced outlines from xerographic images produced with office photocopiers that are calibrated to produce life-sized final images. Others use radiographic images and toneline photography of wax exemplars filled with radio-opaque materials, such as metal filings or barium sulfate. Dependence upon subjective input by the odontologist to trace these images manually is considered problematic. This is because the errors incorporated at any production stage are increased in the final product. The authors have developed a method to generate accurate hollow volume overlays using computer-based techniques. A PowerPC Macintosh computer, flatbed scanner, and Adobe Photoshop (a popular graphical interface application) are used to acquire, select, arrange and export detailed data from class and individual characteristics of a suspect's teeth to acetate film loaded in a high-resolution laser printer. This paper describes this technique to enable the odontologist to produce high-quality, accurate comparison overlays without subjective input.

Bites, Human↗
PubMed1998

Recovery of DNA from human teeth by cryogenic grinding.

DNA has been previously recovered from human teeth for RFLP and PCR-based forensic analysis. In some cases, the maximum amount of undisturbed tooth structure is required for ulterior forensic analysis. But, in most cases, following comprehensive documentation, it is possible to section the tooth longitudinally or horizontally, or crush it to access the DNA-rich core. This technical report describes an alternative method to recover DNA from whole extracted human molar teeth. A 6700 freezer mill was used to pulverize 20 teeth under frozen preparation in liquid nitrogen and sterile conditions. The mean yield of DNA was 30.9 micrograms (18.4 micrograms DNA per gm tooth powder). The resulting fine powder was subjected to organic extraction and subsequently quantified using slot blot hybridization. Aliquots were successfully amplified at three short tandem repeat polymorphic loci. The technique is simple and relatively rapid. Isolation of the samples during pulverization minimizes the risk of contamination.

DNA↗
PubMed1997

An improved method to recover saliva from human skin: the double swab technique.

Human bite mark evidence is often found in violent crimes. Due to the difficulties of physically comparing an injury site on elastic and curved skin surfaces to the teeth of a suspect, the authors have considered using salivary DNA evidence to identify the bite perpetrator. Several techniques were evaluated to determine the best method of recovering saliva from human skin before extracting genomic DNA from the collection substrate. A classical stain recovery technique using a wet cotton swab was tested against one utilizing a wet filter paper. Additionally, a new method, referred to as the double swab technique, using a wet cotton swab followed by a dry cotton swab was also evaluated. After recovering a dried saliva stain, DNA was extracted using the modified Chelex method, quantified using the slot-blot procedure, and amplified at three polymorphic loci. The double swab technique showed the highest percentage recovery of saliva from human skin among the three methods studied. This technique is suggested as an improvement over the classical single wet cotton swab technique.

Bites and Stings↗
PubMed1997

PCR-based DNA typing of saliva stains recovered from human skin.

Human bites in cases of homicide, sexual assault, and abuse are often distorted due to the elasticity and curvature of the skin. Physical comparison of a bite mark to a suspect's teeth is sometimes difficult. Saliva, which is usually deposited during biting, can be collected and analyzed to identify the perpetrator. Using simulated bite mark situations in two experimental series, three samples of 40 microL of whole saliva were deposited on the skin of 27 cadavers (at 33 sites) and three samples of 100 microL of whole saliva were deposited on the skin of 5 cadavers (at 12 sites). Saliva was collected using the double swab technique at t = 5 min, t = 24 h, and t = 48 h. DNA was extracted using the modified Chelex method and submitted to PCR-based typing at two short tandem repeat loci. Results indicate that the concentration of DNA in saliva recovered from skin varies as a function of time since deposition. There is a significant decrease in concentration in the first 24 h but the concentration remains stable from 24 to 48 h. The success of PCR amplification is independent of the time since deposition or the concentration of DNA in the saliva sample. Contamination from the DNA of the cadaver was not found in any of the cases studied.

Bites, Human↗
PubMed1996

Increasing DNA extraction yield from saliva stains with a modified Chelex method.

Recovery, preservation and analysis of body fluid stains is an important aspect of forensic science. PCR-based typing of DNA extracted from recovered stains is often a crucial method to identify a perpetrator or exclude an innocent suspect. This paper reports an improved method of extracting genomic DNA from saliva stains deposited on human skin in simulated bite mark situations. Results of organic (phenol-chloroform) extraction and Chelex extraction were compared to a modified Chelex method developed by the authors. Modifications include pre-extraction preparation with proteinase K and incubations at 56 degrees C and 100 degrees C plus microconcentration of the solution. Quantification results using the classical Chelex extraction method showed that 31.9 +/- 4.22% of the deposited DNA was recovered, but using the modified Chelex extraction method DNA recovery was increased to 47.7 +/- 6.90%. The quantity and quality of extracted DNA was shown to be adequate for PCR-based typing at two STR loci.

Bites and Stings↗
PubMed1996

Personal identification through dental evidence--tooth fragments to DNA.

The most common role of the forensic dentist is the identification of deceased individuals. Comparative dental identification is used to establish to a high degree of certainty that the remains of a decedent and a person represented by antemortem dental records are the same individual. In cases where no antemortem information is available, a postmortem dental profile is completed by the forensic dentist from studies of the teeth, jaws and related facial structures so investigators can narrow the search for antemortem records to a specific population pool. Important clues in resolving the case are available if antemortem data can be obtained for comparison with the postmortem findings. In this article, these responsibilities of the forensic dentist are discussed along with the recent advances in forensic DNA technology that employ dental evidence to assist in resolving violent crimes.

Adolescent↗
PubMed1996

Recognizing and Intervening in Domestic Violence: Proactive Role for Dentistry.

Violence within families and in intimate relationships is now recognized as a widespread problem. Abuse tends to recur and may continue until the victim dies as a result of his or her injuries. Every effort should be made to intervene and stop this chain of events so that the cycle of violence will cease. Although victims are often reluctant to report their abuse, the fac that about 75% of physical injuries are inflicted to the region of the head, face, mouth, and neck places dentists in a particularly good position to recognize the signs of abuse and take steps to intervene. In this article, the signs and symptoms of physical, emotional, and sexual abuse are discussed, and the proactive steps that dental health professionals can take to record and report these cases are outlined.

Journal Article↗