Infectious diseases in wild mice (Mus musculus) collected on and around the University of Pennsylvania (Philadelphia) Campus

Laboratory mice serve as important models in biomedical research. Monitoring these animals for infections and infestations and excluding causative agents requires extensive resources. Despite advancements in detection and exclusion over the last several years, these activities remain challenging for many institutions. The infections and infestations present in laboratory mouse colonies are well documented, but their mode of introduction is not always known. One possibility is that wild rodents living near vivaria somehow transmit infections to and between the colonies. This study was undertaken to determine what infectious agents the wild mice on the University of Pennsylvania (Philadelphia) campus were carrying. Wild mice were trapped and evaluated for parasites, viruses, and selected bacteria by using histopathology, serology, and PCR-based assays. Results were compared with known infectious agents historically circulating in the vivaria housing mice on campus and were generally different. Although the ectoparasitic burdens found on the 2 populations were similar, the wild mice had a much lower incidence of endoparasites (most notably pinworms). The seroprevalence of some viral infections was also different, with a low prevalence of mouse hepatitis virus among wild mice. Wild mice had a high prevalence of murine cytomegalovirus, an agent now thought to be confined to wild mouse populations. Helicobacter DNA was amplified from more than 90% of the wild mice (59% positive for H. hepaticus). Given the results of this study, we conclude that wild mice likely are not a source of infection for many of the agents that are detected in laboratory mouse colonies at the University of Pennsylvania.

[Contribution of paleopathology to defining the pathocoenosis of infectious diseases (Part one)]

Studying the remains of mummies obtained by archaeological research may provide key information concerning historical pathocoenosis. Paleopathology makes it possible to recognise, characterise and connect different features involved in human pathocoenosis, such as epidemiology, in a historical perspective, and cultural development, via the introduction of new livestock farming techniques and agriculture in general. Several distinct pathologies may produce direct and indirect changes in the skeleton of affected individuals. Therefore bone remains represent very important sources of information to study such diseases. Changes related to trauma and nutrition deficiency as well as secondary signs, induced by tuberculosis, brucellosis, leprosy, syphilis, malaria, periostitis and aspecific osteomyelitis, persist in bones. In addition, other diseases may cause indirect alterations and subsequent secondary bone in the skeleton via different mechanisms. A secondary bone dimorphism may be induced by poliomyelitis. Aspecific lesions may arise in a skeletal bone and then cause secondary alterations in near-bone segments. Reviewing studies of paleopathologic research found in the literature, we emphasize the relationship between the appearance of major infectious diseases and the development of human activities; whereas it is clear that the introduction of livestock farming had a key role in the pathocoenosis of distinct infections such as tuberculosis, brucellosis and leprosy, some doubts and uncertainty remain in relation to the origin of others with epidemiologically important pathologies, such as syphilis.

[Heat shock proteins and their role in the development of pathological processes]

Heat shock proteins (HSPs) are the most conserved proteins present in the archea, pro- and eukaryotes. HSPs have a dual function depending on their intra- or extracellular location. Intracellular HSPs play a cytoprotective role providing the cells with mechanisms to prevent damage caused by misfolded, damaged, aggregated, or insoluble proteins. Extracellularly located or membrane-bond HSPs participate in both innate and adaptive immune responses. The recent review focuses on the role of HSPs in the pathogenesis of infections, autoimmune, cardiovascular, oncological, neurodegenerative, and other diseases. HSPs may serve as potential molecular targets for therapeutic intervention in the treatment of various diseases, including cancer, Alzheimer's and Parkinson's diseases. Some HSPs may be used as immunoadjuvants or as HSP-based vaccines for the treatment of infections and cancers.

Clinico-pathological discrepancies in a general university hospital in São Paulo, Brazil

INTRODUCTION

The autopsy rate has continuously diminished over the past few decades, reducing the quality of medical care and the accuracy of statistical health data.

OBJECTIVE

To assess the accuracy of clinical diagnoses by comparing pre- and postmortem findings, and to identify potential risk factors for misdiagnoses.

METHODS

Retrospective evaluations performed between June 2001 and June 2003 in a 2,500-bed tertiary university hospital in São Paulo, Brazil, including 288 patients who died at that institution and had a postmortem examination.

RESULTS

Clinical and autopsy records were reviewed and compared for categorization using the adapted Goldman criteria. The overall major and minor discrepancy rates were 16.3% and 28.1%, respectively. The most common missed diagnoses were pulmonary embolism, pneumonia, and myocardial infarction, and the most prevalent underlying diseases were infectious diseases, cerebro-cardiovascular conditions, and malignancies. Patients age 60 or older had an increased risk of diagnostic disagreement, as did female patients. The period of hospitalization, last admission unit at the hospital and underlying disease were not significantly related to the pre-mortem diagnostic accuracy.

DISCUSSION

The discrepancy rate found in this study is similar to those reported globally. The factors influencing diagnostic accuracy as well as the most commonly missed diagnoses are also consistent with the literature.

CONCLUSION

Autopsy remains a crucial tool for improving medical care, and effort must be focused on increasing its practice worldwide.

CD8+ T cell efficacy in vaccination and disease

Much effort has been devoted to the design of vaccines that induce adaptive cellular immunity, in particular CD8+ T cells, which have a central role in the host response to viral infections and cancers. To date, however, the development of effective T cell vaccines remains elusive. This is due, in part, to the lack of clearly defined correlates of protection and the inherent difficulties that hinder full characterization of the determinants of successful T cell immunity in humans. Recent data from the disparate fields of infectious disease and tumor immunology have converged, with an emphasis on the functional attributes of individual antigen-specific T cell clonotypes, to provide a better understanding of CD8+ T cell efficacy. This new knowledge paves the way to the design of more effective T cell vaccines and highlights the importance of comprehensive immunomonitoring.

Relationship between prognosis of biliary atresia and infection of cytomegalovirus

BACKGROUND

The etiology of biliary atresia is still unknown. It is generally accepted that virus infection may be one of the important causes that lead to biliary atresia. This study aimed to illustrate the relationship between infection of cytomegalovirus and prognosis of biliary atresia.

METHODS

From January 2002 to March 2004, 27 patients who had undergone Kasai's procedure because of biliary atresia were investigated for cytomegalovirus -IgG, IgM and pp65, and their mothers were also examined for confirmation of cytomegalovirus infection. The patients were divided into three groups: infection free group, cytomegalovirus positive group and cytomegalovirus infection group. The rate of jaundice disappearance and the incidence of reflux cholangitis were analyzed statistically. The histopathological changes of the liver were also analyzed.

RESULTS

The positive expression of cytomegalovirus -IgM and cytomegalovirus-pp65 in the patients was higher than that in their mothers (48% versus 14.81% and 37% versus 3.78%, respectively). Compared with the other two groups (80% in the infection free group, and 82% in the cytomegalovirus positive group), the rate of jaundice disappearance after operation in the cytomegalovirus infection group (36%) was significantly lower (P<0.05), and the incidence of reflux cholangitis was higher (P<0.05). Histopathological examination also showed that the degree of liver fibrosis and inflammation was more serious (P<0.05).

CONCLUSIONS

There is a strong correlation between cytomegalovirus infection and a lower rate of jaundice disappearance, also a higher post-operational reflux cholangitis. Liver fibrosis seems to be more severe in biliary atresia patients with cytomegalovirus infection.

The damage-response framework of microbial pathogenesis and infectious diseases

Historical and most currently held views of microbial pathogenesis and virulence are plagued by confusing and imprecise terminology and definitions that require revision and exceptions to accommodate new basic science and clinical information about microbes and infectious diseases. These views are also inherently unable to account for the ability of some microbes to cause disease in certain, but not other hosts, because they are grounded in singular, either microbe-or host-centric views. The damage-response framework is an integrated theory of microbial pathogenesis that puts forth the view that microbial pathogenesis reflects the outcome of an interaction between a host and a microbe, with each entity contributing to the nature of the outcome, which in turn depends on the amount of host damage that results from the host-microbe interaction. This view is able to accommodate new information and explain why infection with the same microbe can have different outcomes in different hosts. This chapter describes the origins and conceptual underpinnings of and the outcomes of infection put forth in, the damage-response framework.

Developmental effects on neonatal mortality and subsequent cerebral palsy in infants exposed to intrauterine infection

BACKGROUND

Intrauterine bacterial infection is important as a high risk factor associated with subsequent brain damage of the newborn.

AIMS

To see if mature fetuses require both hypoxia and intrauterine infection to lead to cerebral palsy, while premature fetuses need infection alone.

STUDY DESIGN

A retrospective cohort study.

SUBJECTS

230 singleton live-born infants of 22 to 32 weeks of gestation, exposed to intrauterine infection during labor and delivery, from 1995 to 2002.

METHODS

Mortality and incidence of cerebral palsy at 2 years old were compared among the 3 groups; immature (n=89, 22-27 weeks), premature (n=73, 28-33 weeks) and mature (n=68, >34 weeks). The relationship between cerebral palsy and fetal pH values was examined.

OUTCOME MEASURES

Mortality and cerebral palsy.

RESULTS

Mortality and cerebral palsy were significantly decreased with advancing gestation. Mortality was significantly decreased after 28 weeks of gestation while cerebral palsy was significantly decreased after 34 weeks of gestation. Acidosis was associated with cerebral palsy in mature infants, but not in less mature infants.

CONCLUSIONS

: Premature infants were more susceptible to intrauterine infection to cause death or cerebral palsy than mature infants. Mature infants may require exposures to both infection and hypoxia but less mature infants need infection alone to cause cerebral palsy, suggesting different pathogenesis during the developmental stage.

Inactivation of amyloid-enhancing factor (AEF): study on experimental murine AA amyloidosis

It is known that amyloid-enhancing factor (AEF) shortens the preamyloid phase in experimentally induced AA amyloidosis in mice. Because it is reported that AEF serves as both a nidus and a template for amyloid formation, AA amyloidosis may have transmissibility by a prion-like mechanism. It has been shown that amyloid fibrils also have AEF activity, and amyloid fibrils with AEF activity were named fibril-amyloid enhancing factor (F-AEF). In this study, we investigated methods to inactivate the AEF activity. AEF was extracted from the thyroid gland obtained at autopsy of a patient with AA amyloidosis. Before injection into mice, AEF was treated with several methods for inactivation. Of all the tested treatments, 1 N NaOH, 0.1 N NaOH, and autoclaving consistently demonstrated complete inactivation of AEF. Heat treatment led to incomplete inactivation, but 0.01 N NaOH, 0.001 N NaOH, pepsin, trypsin, pronase, and proteinase K treatment had no effect on AEF activity. By analysis with transmission electron microscopy, the AEF preparation contains amyloid fibrils, and a change of ultrastructure was shown after 1 N NaOH, 0.1 N NaOH, and autoclaving treatment. Furthermore, immunoblotting of AEF with antihuman AA antibody revealed that the protein band was scarcely found after autoclaving, 1 N NaOH, and 0.1 N NaOH treatment. Our results suggest that, similar to Creutzfeldt-Jakob disease (CJD), amyloidosis may require chemical or autoclaving decontamination.

Infection After Acute Ischemic Stroke

Background and Purpose— Infection after experimental focal ischemia may result from brain-induced immunodepression, but it is unsettled whether a similar syndrome occurs in human stroke.

Summary of Review— Many patients develop infections shortly after acute stroke regardless of optimal management. Mortality is higher in these patients and the severity of stroke is the strongest determinant of the infectious risk. However, it is controversial whether infections promote neurological worsening or alternatively represent a marker of severe disease. The brain and the immune system are functionally linked through neural and humoral pathways, and decreased immune competence with higher incidence of infections has been demonstrated in several acute neurological conditions. In experimental brain ischemia, infections are associated with the activation of the autonomous nervous system and neuroendocrine pathways, which increase the strength of anti-inflammatory signals. A strong cytokine-mediated anti-inflammatory response was recently observed in stroke patients at higher risk of infection, although infection could not demonstrate an independent association with the progression of the symptoms.

Conclusions— The appearance of infection in patients with acute stroke obeys in part to immunological mechanisms triggered by acute brain injury. An excessive anti-inflammatory response is a key facilitating factor for the development of infection, and it is likely that this immunological response represents an adaptive mechanism to brain ischemia. Contrarily, it is unclear whether infection contributes independently to poor outcome in human stroke. Overall, a better understanding of the cross-talk between the brain and the immune system might lead to more effective therapies in patients with acute stroke.

A robustness-based approach to systems-oriented drug design

Many potential drugs that specifically target a particular protein considered to underlie a given disease have been found to be less effective than hoped, or to cause significant side effects. The intrinsic robustness of living systems against various perturbations is a key factor that prevents such compounds from being successful. By studying complex network systems and reformulating control and communication theories that are well established in engineering, a theoretical foundation for a systems-oriented approach to more effectively control the robustness of living systems, particularly at the cellular level, could be developed. Here, I use examples that are based on existing drugs to illustrate the concept of robustness, and then discuss how a greater consideration of the importance of robustness could influence the design of new drugs that will be intended to control complex systems.

Infective disorders of the gastrointestinal tract

Gastrointestinal infections are a major cause of morbidity and mortality worldwide. Infectious organisms are often recovered by microbiological methods, but surgical pathologists may play a very valuable role in diagnosis. This review will focus on infective disorders of the gastrointestinal tract with an emphasis on enterocolitides caused by food‐ and water‐borne pathogens. Diagnostic histological features of selected enteric infections will be emphasized, including those that mimic other inflammatory conditions of the gut (such as ischaemia or idiopathic inflammatory bowel disease), along with available diagnostic methods that can aid in diagnosis.

Current and future drugs targeting one class of innate immunity receptors: the Toll-like receptors

Innate immunity receptors are germline-encoded receptors that can sense molecular signatures of pathogens and cancer cells. Recent advances in immunology demonstrate the key role of these receptors in inflammation and initiation of subsequent immune responses, including adaptive immunity. Pharmaceutical interest in this field has grown with the retrospective demonstration that some marketed drugs targeting cancer or infectious diseases act via those receptors. In this review, I present an update on the scientific rationale for targeting one class of innate immunity receptor, the Toll-like receptors, and an update on the development status of corresponding drug candidates in infectious diseases, cancer, allergy and vaccines.

Pneumonia models and innate immunity to respiratory bacterial pathogens

Preclinical sepsis models have been used for decades to study the pathophysiologic processes during sepsis and shock. Although these studies revealed promising immunomodulating agents for the treatment of sepsis, clinical trials evaluating the efficacy of these new agents in patients with sepsis were disappointing. The main reason for this unsatisfactory experience might be that unlike the clinical situation, most of these preclinical models are devoid of a localized infectious source from which the infection disseminates. Studies on the effects of several immunomodulating strategies have demonstrated strikingly opposite results when sepsis models with a more natural route of infection, such as pneumonia, were used. In this review, we will give insights into pneumonia models and discuss results and differences in the innate immune responses during distinct pulmonary infection models.

DNA microarrays--an armory for combating infectious diseases in the new century

DNA microarrays are high-throughput platforms that take advantage of the vast amount of sequence information and allow scientists to perform gene expression profiling or genotyping studies on a "global" or "genome-wide" scale. The global monitoring of gene expression in hosts and pathogens, either separately or interactively, has given us systemic views of the disease mechanisms. Ongoing improvements in DNA sequencing and microarray technologies continue to open up new opportunities for better understanding and developing more effective approaches in diagnosis, treatments, and preventions of infectious diseases. This review focuses on the latest developments and applications of the DNA microarray technologies designed for studying pathogens in the areas of pathogenesis, host-pathogen interaction, drug response, vaccine development, and disease agent identification. Issues and challenges in the analysis, management and interpretation of microarray data are also addressed.

[New immunology--immunology of pattern recognition receptors]

Pattern recognition receptors (PRRs) have been found on all cells of the body--cells of the innate and adaptive immune systems, epithelial and endothelial cells, keratinocytes, etc. PRRs can recognize specific molecular structures of microorganisms as well as allergens and other substances. The interaction with ligands of foreign microorganisms activates PRRs, after which host cells start to produce cytokines to both specifically activate innate immunity and to control adaptive immune reactions. On the other hand, no immune response develops against microorganisms of the normal microflora. Practically, the development of all immune responses is controlled by PRRs. These responses start in epithelial cells, skin cells, and vascular epithelial cells, which meet alien first. The immune system uses these cells to control the composition of normal microflora. Accordingly, the definition of immune system functions should be complemented by the regulation of body's microflora in addition to the protection from alien and altered self.

The thymus is a common target organ in infectious diseases

Infectious disease immunology has largely focused on the effector immune response, changes in the blood and peripheral lymphoid organs of infected individuals, and vaccine development. Studies of the thymus in infected individuals have been neglected, although this is progressively changing. The thymus is a primary lymphoid organ, able to generate mature T cells that eventually colonize secondary lymphoid organs, and is therefore essential for peripheral T cell renewal. Recent data show that normal thymocyte development and export can be altered as a result of an infectious disease. One common feature is the severe atrophy of the infected organ, mainly due to the apoptosis-related depletion of immature CD4⁺CD8⁺ thymocytes. Additionally, thymocyte proliferation is frequently diminished. The microenvironmental compartment of the thymus is also affected, particularly in acute infectious diseases, with a densification of the epithelial network and an increase in the deposition of extracellular matrix. In the murine model of Chagas disease, intrathymic chemokine production is also enhanced, and thymocytes from Trypanosoma cruzi-infected mice exhibit greater numbers of cell migration-related receptors for chemokines and extracellular matrix, as well as increased migratory responses to the corresponding ligands. This profile is correlated with the appearance of potentially autoreactive thymus-derived immature CD4⁺CD8⁺ T cells in peripheral organs of infected animals. A variety of infectious agents—including viruses, protozoa, and fungi—invade the thymus, raising the hypothesis of the generation of central immunological tolerance for at least some of the infectious agent-derived antigens. It seems clear that the thymus is targeted in a variety of infections, and that such targeting may have consequences on the behavior of peripheral T lymphocytes. In this context, thymus-centered immunotherapeutic approaches potentially represent a new tool for the treatment of severe infectious diseases.

Anatomic laboratory and forensic aspects of biological threat agents

Anatomic pathology of surgical and cytologic samples and forensic autopsies is a critical component of our defense against biological terrorism. In many instances, rapid, valuable diagnosis may be obtained by the proper immediate use of the anatomic pathology laboratory. Included in this field is the work of medical examiners and coroners, who are essential public health partners for terrorism preparedness and response. The investigation of sudden, suspicious, violent, unattended, and unexplained deaths may provide the first clue to a deliberate biological attack. Medicolegal autopsies are essential to making organism-specific diagnoses in deaths caused by biological terrorism.

Pathological findings in a captive colony of maras (Dolichotis patagonum )

This paper describes the causes of death of 54 maras (Dolichotis patagonum) in a captive colony in Mexico over a period of seven years. There were 35 adults, 11 juveniles, five neonates, two fetuses and one stillbirth--27 males, 21 females and six whose sex was not determined. Trauma was the cause of 25 deaths, and there were eight cases of fatal bacterial infection. Besnoitiosis was the only parasitic disease found frequently (13 cases), and was associated with fatal interstitial pneumonia in three juveniles. Right-sided hypertrophic cardiomyopathy attributed to high altitude was observed in 26 maras, and in three cases death was attributed to acute cardiac dysfunction. Two maras died of disseminated histoplasmosis and two of hyperthermia. Additional causes of death included one case each of uterine torsion, intestinal intussusception, aspiration pneumonia and hydranencephaly. Gastric erosions with luminal haemorrhage were found in 27 of the maras and splenic lymphoid depletion in 20, changes that were attributed to stress.