Co-amplification of microbial DNA: A novel observation of a misconstrued second peak at locus D7S820.

DNA fingerprinting, a gold standard, is one of the most powerful tool in applied sciences especially helpful in criminal investigation. Entering in advanced era of forensic DNA, profile reading is much trickier than ever. An unusual DNA profile was observed from a nail swab of female brutally murdered in a domestic violence case. At first, DNA profile was misconstrued as heterozygote at locus D7S820 but later, it was confirmed as homozygous from other evidence items submitted in the same case. Subsequent reprocessing of the same sample, from the extraction stage through to DNA profiling and DNA profile form victim's blood, conclusively established that the unusual peak is from a non-specific microbial presence at that locus.

Identification of the polymer-bounded drugs on the fabric surface: A challenge to the forensic drug analysts.

Drug trafficking through concealment has always been a method of choice for drug traffickers all around the world. This case shares a new trend in the smuggling of illicit drugs by applying a coating of drug and polymer mixture on fabric. A white fabric sample was submitted by a law enforcement agency to detect the presence of any explosive material on its surface. Later on it was also tested for illicit drugs. Stereomicroscope and Scanning Electron Microscope/Energy Dispersive X-ray Detector (SEM/EDX) were applied for microscopic examination. Acetone extract of the sample was analyzed for explosives by explosive detection kit, Gas Chromatography Mass Spectrometry (GCMS), and Fourier Transform Infrared Spectroscopy (FTIR). The routine method involving methanol as solvent was used to check heroin presence. Methanol extract of the sample was analyzed by Mecke test and GCMS. Stereomicroscope and SEM/EDX revealed the presence of some unusual coating on one side of fabric. No explosive material was detected; instead GCMS (method 1) confirmed the presence of heroin (mass fragments 268, 310, 327, and 369 m/z) and FTIR spectrum revealed presence of a polymeric material (dyneema). No drug was identified by GCMS (method 2). Method 2 was modified by replacing methanol with acetone and including an additional step of sonication for 30 min. Acetone extract showed green color with Mecke reagent and a strong signal of heroin on GCMS. This modified extraction method acted well to unbind the coated material from the fabric and to disentangle the drug from the polymer.

PFSA DNA database: A tool to hunt the serial offenders.

A forensic DNA database comprises of thousands of DNA profiles generated from suspects, convicts or even from common people from society. It is used for the cross-matching of DNA profiles obtained from evidence items collected from a crime scene. These databases are playing a core role in clearing the innocent and solving the dead-end unresolved crimes ultimately leading to crime reduction. In March, 2017, a nine years old minor girl was raped in district Khushab (Province Punjab). The medico-legal examiner indicated brutal sexual violence on the victim. Police apprehended a suspect who was excluded as the source of foreign male DNA from tested evidence items. Thus the case put up a question mark on the capabilities and efficiency of the police. An unknown male DNA profile obtained from evidence items was uploaded to PFSA DNA Database to maintain record. Later on, a suspect was arrested by Karachi (Province Sindh) police in another rape case, DNA profile of suspect was searched in the PFSA DNA Database. This generated DNA profile matched with the foreign DNA profile obtained from evidence items of minor victim, hence this atrocious crime was resolved. PFSA DNA Database provides support to criminal prosecution and also leads to identify potential suspects. It took years of effort to develop the rich PFSA DNA Database which subsequently proved to be fruitful in the exoneration of innocents and conviction of offenders in criminal cases.

Fatal Intoxications Due to Administration of Isosorbide Tablets Contaminated with Pyrimethamine.

In January 2012, 664 cases of pyrimethamine toxicity and 151 deaths were reported among cardiac patients that had recently received free medicines from pharmacy of Punjab Institute of Cardiology, Lahore, Pakistan. These patients, ages ranged from 58 to 75 years, were prescribed simvastatin, clopidogrel, aspirin soluble, isosorbide mononitrate, and amlodipine. On examination of medications being given to them, it was found that a particular batch of isosorbide mononitrate tablets was contaminated with 50 mg pyrimethamine. Cardiac patients were taking isosorbide contaminated with pyrimethamine twice daily (100 mg pyrimethamine/day), whereas therapeutic dose of pyrimethamine for malaria is 25 mg/week. Postmortem urine, cardiac blood, and femoral blood specimens of three deceased males were submitted to author's laboratory for analysis. Postmortem toxicological analysis revealed that pyrimethamine concentration fell within the range of 1-10 µg/mL by liquid chromatography. Clinical, autopsy, histopathological, and toxicological findings strongly suggested toxicity due to pyrimethamine accumulation that resulted in deaths of these cardiac patients.