Sudden unexpected death as a result of primary aortoduodenal fistula identified with postmortem computed tomography.

Aortoenteric fistula (AEF) is an uncommon source of upper gastrointestinal (GI) tract hemorrhage, commonly occurring in persons with previous aortic surgery. Non-surgery related AEFs (primary AEFs) may occur in association with atherosclerotic lesions, infections, malignancies, or, rarely, result from penetrating/eroding foreign bodies. Given its rarity, primary AEF is not commonly considered in the pathologist's preliminary list of differential diagnoses at the commencement of an autopsy; however, the use of postmortem cross-sectional imaging may allow for the identification of primary AEF as a reasonable differential diagnoses prior to conventional autopsy. The current case outlines the forensic presentation, postmortem computed tomography (PMCT) features, and autopsy findings of a recent case of primary AEF resulting in lethal gastrointestinal hemorrhage. In such cases, PMCT features supporting primary AEF as the underlying cause of death include an atherosclerotic aneurysm abutting a segment of the GI tract with no definite soft tissue plane of separation, luminal GI contents of similar radiographic density to the aortic contents, lack of previous aortic surgery, and lack of a competing explanation for GI hemorrhage or a competing cause of death. Deaths from massive enteric hemorrhage without a medical history to suggest an underlying cause for the hemorrhage would fall under medicolegal jurisdiction and may, by examination of scene and circumstances alone, initially seem suspicious. This case demonstrates how PMCT could be used by a team of expert forensic radiologists and forensic pathologists to rapidly feedback vital information on the cause and manner of death to the criminal justice system.

Fatal laryngeal angioedema: a case report and a workup of angioedema in a forensic setting.

Angioedema is an episodic swelling of the deep dermis, subcutis, and/or submucosal tissue due to an increase in local vascular permeability. Swelling may involve skin, respiratory, and gastrointestinal tracts. The most commonly involved areas are the periorbital region and the lips. Here we report a case of a fatal laryngeal obstruction due to angioedema likely caused by an angiotensin-converting-enzyme inhibitor. The decedent, a 58-year-old man, was witnessed developing sudden facial swelling and acute respiratory difficulties quickly followed by unresponsiveness. His past medical history suggested that this was his second episode of angioedema without urticaria. Postmortem examination revealed a complete laryngeal obstruction in the absence of infection, neoplasm, or autoimmune disease. Postmortem computed tomography of the head and neck showed a complete obstruction of the upper airway. Based on the current understanding of the pathophysiology of different types of angioedema, we will suggest a workup of angioedema without urticaria in the forensic setting and offer readers resources they can use in their practice.

Functional characterization of human immunodeficiency virus type 1 nef genes in patients with divergent rates of disease progression.

We have studied the sequence and function of the human immunodeficiency virus type 1 (HIV-1) nef genes from nine patients with highly divergent rates of disease progression enrolled in a longitudinal study of HIV disease. Over an average of 7.8 years of follow-up, three patients had net positive changes in CD4+ T-cell counts, three patients had net negative changes in CD4+ T cells but did not develop AIDS, and three patients progressed to AIDS. The nef gene from each of these patients was amplified and cloned, and the sequence of 8 to 10 clones was determined. Only 2 of 88 (2.3%) nef genes recovered from these nine patients were grossly defective. Moreover, there was no relationship between the phylogeny of nef sequences and the corresponding rates of disease progression from these patients. Representative nef genes from all nine patients were tested for their abilities to downregulate cell surface CD4 in a transient-transfection assay. There was no correlation found between the functions of the nef genes from these patients and their corresponding rates of disease progression. We conclude that the nef gene is not a common mediator of the rate of HIV disease progression in natural infection.

Defective accessory genes in a human immunodeficiency virus type 1-infected long-term survivor lacking recoverable virus.

We have been studying a patient who acquired human immunodeficiency virus (HIV) infection via a blood transfusion 13 years ago. She has remained asymptomatic since that time. The blood donor and two other recipients have all died of AIDS. Although this patient has shown persistently strong seroreactivity to HIV type 1 (HIV-1) antigens by Western blot (immunoblot), she has been continually HIV culture negative in results from multiple laboratories over the last 6 years and has a very low viral burden. Her CD4+ T-cell count has fluctuated around a mean of 399 cells per microliters, with little change in lymphocyte subset percentages. Strong cellular immune responses to HIV-1 epitopes by this patient have been demonstrated. We now report the results of an intensive molecular genetic analysis of the HIV-1 proviral quasispecies from this patient sampled over 5 years. Long terminal repeat region sequences supported the argument for normal basal and Tat-mediated promoter activities. Sequential sequencing of the nef gene revealed a low frequency (8.3%) of defective genes and a striking lack of sequence evolution. Functional analysis of predominant nef genes by both a cell surface CD4 downregulation and a viral infectivity complementation assay showed wild-type function. In contrast, sequential analysis of an amplicon containing the vif, vpr, vpu, tat1, and rev1 genes revealed the presence of inactivating mutations in 64% of the clones. These data suggest that this patient, initially infected with a virulent swarm of HIV-1, is presently infected with a more-attenuated viral quasispecies as a result of effective host immunity.

Naturally occurring genotypes of the human immunodeficiency virus type 1 long terminal repeat display a wide range of basal and Tat-induced transcriptional activities.

The primary body of information on the structure of human immunodeficiency virus type 1 (HIV-1) long terminal repeat (LTR)/gag leader genotypes has been determined from the analysis of cocultivated isolates. Functional studies of this regulatory portion of the provirus have been derived from the study of in vitro-generated mutations of laboratory-adapted molecular clones of HIV-1. We have performed a longitudinal analysis of molecular clones from the LTR/gag leader region amplified directly from the peripheral blood of four patients over three years. We have found a remarkable number of point mutations and length polymorphisms in cis- and trans-acting regulatory elements within this cohort. Most of the length polymorphisms were associated with duplications of Sp1 and TCF-1 alpha sequences. These mutations were associated with a wide range of transcriptional activities for these genotypes in a reporter gene assay. Mutations in conserved Sp1 sequences correlated with a diminished capacity of such genotypes to bind purified Sp1 protein. Although no generalized trend in transcriptional activity was seen, a single patient accumulated mutations in NF-kappa B, Sp1, and TAR elements over this period. The analysis of naturally occurring mutations of LTR genotypes provides a means to study the molecular genetic consequences of virus-host interactions and to assess the functional impact of HIV therapeutics.

Negative-strand RNA transcripts are produced in human immunodeficiency virus type 1-infected cells and patients by a novel promoter downregulated by Tat.

Current understanding of human immunodeficiency virus type 1 (HIV-1) transcription is based on unidirectional expression of transcripts with positive-strand polarity from the 5' long terminal repeat. We now report HIV-1 transcripts with negative-strand polarity obtained from acutely and chronically infected cell lines by use of a template orientation-specific reverse transcriptase-PCR assay. These findings were confirmed in natural infection by analysis of RNA derived from peripheral blood mononuclear cell samples from 15 HIV-1-infected patients. A cDNA derived from a 2.3-kb polyadenylated HIV-1 RNA with negative-strand polarity which encodes a highly conserved 189-amino-acid open reading frame antiparallel to the envelope gene was isolated from acutely infected A3.01 cells. Through use of reporter gene constructions, we further found that a novel negative-strand promoter functions within the negative response element of the 3' long terminal repeat, which is downregulated by coexpression of Tat. Site-directed mutagenesis experiments demonstrated that NF-kappa B I and USF sites are crucial for negative-strand promoter activity. These data extend the coding capacity of HIV-1 and suggest a role for antisense regulation of the viral life cycle.