Pathology and pathogenesis of bioterrorism-related inhalational anthrax

During October and November 2001, public health authorities investigated 11 patients with inhalational anthrax related to a bioterrorism attack in the United States. Formalin-fixed samples from 8 patients were available for pathological and immunohistochemical (IHC) study using monoclonal antibodies against the Bacillus anthracis cell wall and capsule. Prominent serosanguinous pleural effusions and hemorrhagic mediastinitis were found in 5 patients who died. Pulmonary infiltrates seen on chest radiographs corresponded to intraalveolar edema and hyaline membranes. IHC assays demonstrated abundant intra- and extracellular bacilli, bacillary fragments, and granular antigen-staining in mediastinal lymph nodes, surrounding soft tissues, and pleura. IHC staining in lung, liver, spleen, and intestine was present primarily inside blood vessels and sinusoids. Gram's staining of tissues was not consistently positive. In 3 surviving patients, IHC of pleural samples demonstrated abundant granular antigen-staining and rare bacilli while transbronchial biopsies showed granular antigen-staining in interstitial cells. In surviving patients, bacilli were not observed with gram's stains. Pathological and IHC studies of patients who died of bioterrorism-related inhalational anthrax confirmed the route of infection. IHC was indispensable for diagnosis of surviving anthrax cases. The presence of B. anthracis antigens in the pleurae could explain the prominent and persistent hemorrhagic pleural effusions.     

Dural repair using acellular human dermis: experience with 200 cases: technique assessment

OBJECTIVE: Many craniotomies require a watertight dural closure. When primary dural repair is not possible, a graft is necessary. Autograft material is not always easily accessible or available, necessitating the use of other material. We performed 200 craniotomies using an acellular human dermal graft (AlloDerm; LifeCell Corp., The Woodlands, TX) to determine its suitability as a dural substitute. METHODS: From June 1996 through March 1998, all patients at Allegheny General Hospital who required a dural substitute graft and in whom autograft harvest was impractical or impossible received the acellular dermal autograft. The running suture technique was used to form a watertight seal. RESULTS: After follow-up for a minimum of 1 year, seven patients have required subsequent surgery. Three patients developed cerebrospinal fluid leaks that were repaired without removing the dermal graft. Four patients developed wound infections that required debridement. In each patient, the graft seemed to be uninvolved in the infectious process and was left in place. The patients were administered antibiotics postoperatively, and there have been no recurrent infections. No adhesion formation or scarring was noted around or underneath the graft in any patient. CONCLUSION: AlloDerm is a reasonable alternative to the available dural graft materials. Its handling characteristics are similar to those of dura, it is biologically inert, and it does not produce adhesion formation.     

Adipose tissue polyunsaturated fatty acids and metabolic syndrome among adult parents and their children

Background and aims

Polyunsaturated fatty acids (PUFA) may play a role in the etiology of the metabolic syndrome (MetS). The aim of the study was to examine the associations of adipose tissue PUFA biomarkers with MetS among parents and children in Mesoamerica.

Diabetic neuropathic cachexia and acute bilateral cataract formation following rapid glycaemic control in a newly diagnosed type 1 diabetic patient.

In patients with Type 1 diabetes mellitus (DM), the development of complications within the first few years of diagnosis is very unusual and the development of complications within weeks of commencement of insulin therapy is exceptional. Diabetic neuropathic cachexia, unlike the other more common neuropathies associated with diabetes, is a rare form of peripheral neuropathy characterized by profound weight loss, painful dysaesthesias over the limbs and trunk with spontaneous resolution usually occurring within a year. The morphologically distinct diabetic or metabolic cataract in patients with newly diagnosed Type 1 DM is also a rare complication. We describe the first case of a young man with newly diagnosed Type 1 DM who developed these two rare complications within 3 months of diagnosis and insulin therapy commencement. Rapid development of complications in this patient raises two possibilities, i.e. a probable link between the pathophysiology of these two complications following rapid glycaemic control, and a subset of patients with unusual susceptibility to complications. We re-emphasize the need for vigilant monitoring of complications in young diabetic patients, even in the first few years of their disease. In particular, young patients with visual impairment should be evaluated carefully for evidence of treatable eye complications.     

A novel sensor kinase-response regulator hybrid controls biofilm formation and type VI secretion system activity in Burkholderia cenocepacia

Burkholderia cenocepacia is an important opportunistic pathogen causing serious chronic infections in patients with cystic fibrosis (CF). Adaptation of B. cenocepacia to the CF airways may play an important role in the persistence of the infection. We have identified a sensor kinase-response regulator (BCAM0379) named AtsR in B. cenocepacia K56-2 that shares 19% amino acid identity with RetS from Pseudomonas aeruginosa. atsR inactivation led to increased biofilm production and a hyperadherent phenotype in both abiotic surfaces and lung epithelial cells. Also, the atsR mutant overexpressed and hypersecreted an Hcp-like protein known to be specifically secreted by the type VI secretion system (T6SS) in other gram-negative bacteria. Amoeba plaque assays demonstrated that the atsR mutant was more resistant to Dictyostelium predation than the wild-type strain and that this phenomenon was T6SS dependent. Macrophage infection assays also demonstrated that the atsR mutant induces the formation of actin-mediated protrusions from macrophages that require a functional Hcp-like protein, suggesting that the T6SS is involved in actin rearrangements. Three B. cenocepacia transposon mutants that were found in a previous study to be impaired for survival in chronic lung infection model were mapped to the T6SS gene cluster, indicating that the T6SS is required for infection in vivo. Together, our data show that AtsR is involved in the regulation of genes required for virulence in B. cenocepacia K56-2, including genes encoding a T6SS.     

Short-Term Memory During Stage-2 Sleep

A recently-proposed model of dream recall phenomena (Koulack & Goodenough, 1976) assumes a short-term memory store which functions during sleep, and from which either dreams or externally-delivered stimuli can be retrieved if the subject is awakened during the life of the short-term trace. To test this assumption, two experiments were designed to examine short-term memory for auditory stimuli over intervals of uninterrupted stage-2 sleep. A random series of single-digit numbers was presented at the rate of one every 30 sec throughout the night, at an intensity slightly above normal conversational levels. Subjects habituated to the sound and did not awaken spontaneously. Experimental awakenings took place either at 1 sec (Experiment 1) or at 1, 5, or 10 sec (Experiment 2) after selected target stimuli, and the subjects were asked to recall which number they had heard. Significant recall was obtained over intervals of up to 10 sec, and the likelihood of recall was inversely related to reaction times to the awakening stimulus. Repeating the target numbers at 30-sec intervals increased EEG alpha activity and K-complex amplitude, suggesting that some form of trace persists for at least 30 sec.