[HPV-associated carcinomas of the female genital tract. Molecular mechanisms of development]. / HPV-assoziiertes Karzinom des weiblichen Genitaltrakts. Molekulare Mechanismen der Entstehung.

Infections with human papillomaviruses (HPV) are a common occurrence in both men and women. In contrast HPV-associated neoplasias are relatively rare and occur only in certain areas of the body. The virus has obviously developed efficient mechanisms for its persistence without inducing too much damage to the host. The formation of neoplasia seems to be more an exception. Epigenetic mechanisms play an important role in the regulation of viral gene expression. Investigations have indicated that exactly the transition from the permissive infection stage to a transformation stage, where neoplastic alterations can occur due to expression of the viral oncogenes, is associated with certain methylation patterns of the viral genome which promote the expression of the oncogenes E6 and E7. The transforming stage is seen as the actual carcinogenic event and can be immunohistochemically detected by the biomarker p16(INK4a).

Transmissible mink encephalopathy: infectivity of corneal epithelium.

Corneal epithelium from hamsters dying of transmissible mink encephalopathy contained a virus titer of 10-4.8 times the 50 percent lethal dose (10-4.8 LD50) per 0.05 milliliter when assayed as a cell suspension derived directly from the infected animal. After one passage in tissue culture, an equivalent concentration of cells contained only 10-0.8 LD50 per 0.05 milliliter.. It is concluded that corneal tissues are infectious; the infectivity may be mainly associated with free nerve endings. However, the most important immediate inference is that corneas from human beings affected with Creuzfeldt-Jakob disease are likely to be lethal if transplanted to healthy recipients.

Experimental subacute spongiform virus encephalopathies in primates and other laboratory animals.

The host range of subacute spongiform virus encephalopathies is described. The asymptomatic incubation period and the duration of the illnesses in various species of animal hosts is discussed along with information on additional species of Old World and New World monkeys and the domestic cat, which have been shown to be susceptible to subacute spongiform virus encephalopathies.

Infection-specific particle from the unconventional slow virus diseases.

Scrapie-associated fibrils, first observed in brains of scrapie-infected mice, were also observed in scrapie-infected hamsters and monkeys, in humans with Creutzfeldt-Jakob disease, and in kuru-infected monkeys. These fibrils were not found in a comprehensive series of control brains from humans and animals affected with central nervous system disorders resulting in histopathologies, ultrastructural features, or disease symptoms similar to those of scrapie, kuru, and Creutzfeldt-Jakob disease. These fibrils are also found in preclinical scrapie and in the spleens of scrapie-infected mice; they are a specific marker for the "unconventional" slow virus diseases, and may be the etiological agent.

Prion diseases.

There have been remarkably rapid advances in the understanding of prion diseases over the past year. The controversial notion that the transmissible agent may be an abnormal isoform of a host-encoded protein, the prion protein, is now gaining wide acceptance. The conundrum of how a disease can both be inherited as an autosomal dominant condition and also be experimentally transmissible by inoculation is beginning to make sense.

Imaging of slow viruses.

The symptoms associated with slow viral or prion diseases of the central nervous system tend to have multiple neurologic symptoms, and different patients may present with different symptoms. This review discusses the most common slow virus infections and their imaging findings.

Utility of positive bronchoalveolar lavage in predicting respiratory failure after hematopoietic stem cell transplantation: a retrospective analysis.

Pulmonary complications occur frequently after hematopoietic stem cell transplantation (HSCT) and account for considerable mortality when associated with respiratory failure. Bronchoalveolar lavage (BAL) is commonly used in the diagnostic evaluation of pulmonary infiltrates in HSCT patients. Although the yield of BAL is well established in this setting, the impact on outcome is controversial. In addition, respiratory failure in HSCT patients is associated with high mortality. To determine if positive BAL predicted less respiratory failure and better survival, a retrospective review (between 1992 and 1998) of all HSCT patients who had bronchoscopy with BAL as part of their diagnostic evaluation for new pulmonary infiltrates was performed. Twenty-one patients met the inclusion criteria. Eleven patients (52%) had a positive BAL, defined as the isolation of infectious microorganisms or pulmonary hemorrhage in the lavage specimen. Most of the positive findings were pathogenic organisms (bacterial, fungal, and viral). Respiratory failure (defined as need for both intubation and mechanical ventilation) occurred in 11 of 21 patients (52%)-8 of 11 (73%) who had positive BAL compared with 3 of 10 (30%) who had negative BAL (P = .09). The overall mortality rate was 11 of 21 patients (52%). All deaths except one occurred as a direct result of respiratory failure. Although this study confirmed the high mortality rate in HSCT patients with respiratory failure, the BAL results were not predictive of outcome.

[Disease concept of the slow virus infection].

This article gives a brief history of the terminology of slow virus infection, the conceptual change that occurred in it, the features common to slow infection and the current concept of slow virus infection. Björn Sigurdsson from the field of veterinary medicine proposed slow virus infection as unique mode of infection in 1954. Its initial concept was remodeled along with the general acceptance of prion theory of sheep scrapie that was proposed in 1982. The features common to slow infection include very long latency, unanimous poor prognosis, central nervous system involvement, etc. Currently the slow infection comprises those caused by slow conventional viruses that is the slow virus infection (for example subacute sclerosing panencephalitis and progressive multifocal encephalopathy in human and visna-maedi in sheep) and prion diseases (for example kuru, Creutzfeldt-Jakob disease, Gerstmann-Sträussler-Scheinker syndrome in human, scrapie and bovine spongiform encephalopathy).

[Establishment of the concept of prion diseases].

The history of prion diseases is derived from descriptions of scrapie of sheep and goats in the eighteenth century. In 1920, Creutzfeldt-Jakob disease was reported as the first case of human prion diseases, which was recognized as subacute spongiform encephalopathy, one of neurodegenerative diseases. Afterwards, many transmission experiments were performed, which lead to the establishment of the fundamental concept, transmissible spongiform encephalopathy(TSE). The infectious agent was supposed to be a novel virus, so TSE was classified into slow virus infection. In 1982, Prusiner investigated the infectious fraction of scrapie-infected brain homogenate, defined the infectious agent as proteinaceous infectious particles that resist inactivation by procedures that modify nucleic acid and newly designated as prion after virion in viral infection.

Helminths as vectors of pathogens in vertebrate hosts: a theoretical approach.

Pathogens frequently use vectors to facilitate transmission between hosts and, for vertebrate hosts, the vectors are typically ectoparasitic arthropods. However, other parasites that are intimately associated with their hosts may also be ideal candidate vectors; namely the parasitic helminths. Here, we present empirical evidence that helminth vectoring of pathogens occurs in a range of vertebrate systems by a variety of helminth taxa. Using a novel theoretical framework we explore the dynamics of helminth vectoring and determine which host-helminth-pathogen characteristics may favour the evolution of helminth vectoring. We use two theoretical models: the first is a population dynamic model amalgamated from standard macro- and microparasite models, which serves as a framework for investigation of within-host interactions between co-infecting pathogens and helminths. The second is an evolutionary model, which we use to predict the ecological conditions under which we would expect helminth vectoring to evolve. We show that, like arthropod vectors, helminth vectors increase pathogen fitness. However, unlike arthropod vectors, helminth vectoring increases the pathogenic impact on the host and may allow the evolution of high pathogen virulence. We show that concomitant infection of a host with a helminth and pathogen are not necessarily independent of one another, due to helminth vectoring of microparasites, with profound consequences for pathogen persistence and the impact of disease on the host population.

Intracerebral inoculation of experimental animals with brain tissue from patients with schizophrenia. Failure to observe consistent or specific behavioral and neuropathological effects.

To test the possibility that some cases of schizophrenia result from infection with a transmissible slow viral agent, 57 experimental animals (six chimpanzees, 12 Old World monkeys, 17 New World monkeys, and 22 guinea pigs) were inoculated intracerebrally with brain tissue from ten patients and followed up for six years. Behavioral comparisons with control animals revealed no consistent behavioral differences. Histological, immunohistochemical, and morphometric examination of brains of animals that died revealed no specific neuropathological abnormalities. These findings do not support a role for a virus-induced slow infection in the pathogenesis of schizophrenia but must be weighed against methodological limitations in animal susceptibility, disease communicability, and assay sensitivity.

Antiserum to scrapie-associated fibril protein reacts with amyloid plaques in familial transmissible dementia.

Scrapie-associated fibrils (SAF) are disease-specific markers for the unconventional agent-induced, transmissible spongiform encephalopathies. Polyclonal rabbit antiserum to SAF protein was reacted with brain sections from scrapie-infected mice, two familial cases of transmissible dementia, and three cases of Alzheimer's disease (AD). Specific immunostaining of cerebral amyloid plaques occurred in the scrapie-infected mice and in the two familial cases of transmissible dementia. No immunoreactivity was detected in senile plaques or neurofibrillary tangles in the three cases of AD. Our results suggest that SAF, the causative pathogenic agent, and extracellular deposits of amyloid in the brain are closely related. Immunohistochemical detection of SAF protein could serve as a useful diagnostic adjunct in the postmortem evaluation of difficult cases of dementia. The identification of SAF protein in the brains of two affected members of a family combining the clinical and pathological features of Creutzfeldt-Jakob disease (CJD) and the Gerstmann-Straüssler syndrome (GSS) substantiates earlier conclusions of a nosological relationship between the two. Our study provides further evidence of the similarity of SAF protein to prion protein (PrP 27-30).

Senile dementia of the Alzheimer type: possibility of infectious etiology in genetically susceptible individuals.

The concept that SDAT is caused by an infectious agent acting in a genetically susceptible host was approached from a number of standpoints. The similarities between SDAT and the transmissible encephalopathies are discussed. One of the areas of similarity is the influence of genetic background on the development and expression of both conditions. Evidence is presented showing that genetics plays a role in many cases of SDAT and that there are known genetically controlled phenomena, the incidence of which is positively correlated with SDAT. For human encephalopathies the genetics of CJD and GSS are detailed. In experimental systems with scrapie, the influence of genetic control, operating through both host and agent, on the outcome of infection with scrapie is described. The events controlled include length of incubation period, type of lesions and their distribution and intensity. In the context of the human diseases, scrapie provides a model for the known human encephalopathies and for SDAT.

The illusion of simplicity: the medical model revisited.

Traditional medical models have been found to be linear, restrictive, and oversimplified. Only a truly biological model, encompassing evolutionary as well as molecular and cellular biology, can account for the complex origins, forms, and effects of disease, which are illustrated by a discussion of hepatitis B and slow virus disease. An updated biological model of disease takes into account predisposition to disease, the timing and route of infection, multiple disease forms, variable adaptive response, and the role of social and cultural factors and views disease as a failure of adaptation in one or more systems. Its application to psychiatry is shown in a discussion of stress, bereavement, and separation.

Stem loops in HIV and prion protein mRNAs.

Tat-dependent trans-activation in HIV requires presentation of a CUGGG pentanucleotide at the end of a stem loop within the tar site of the viral long terminal repeat. A tandem repeat within the open reading frame of the prion protein (PrP) mRNA is able to form similar stem loop structures with which the HIV tat protein could interact, disturbing PrP translation. Self-amplification of such a disturbance has been suggested as the cause of the scrapie group of diseases, including the scrapie-like human dementiae. The same mechanism may underly AIDS encephalopathy.

Gerstmann-Sträussler-Scheinker disease. I. Extending the clinical spectrum.

We present the clinical findings in affected members of a large kindred with Gerstmann-Sträussler-Scheinker disease. Sixty-four patients exhibited progressive ataxia, dementia, and parkinsonian features. Inheritance appears to be autosomal dominant. Impaired smooth-pursuit eye movements, defective short-term memory, clumsiness of the hands, and ataxia of gait develop in the late 30s to early 60s. Eye movement abnormalities are characteristic of cerebellar dysfunction. Dementia progresses gradually over several years. Later, rigidity and bradykinesia appear and, at this stage, there is often psychosis or severe depression with rapid weight loss. Death occurs in 6 months to 2 years after onset of rigidity. Magnetic resonance imaging in 2 affected individuals showed cerebellar atrophy. There is decreased T2 signal in the basal ganglia, consistent with iron deposition.

Gerstmann-Sträussler-Scheinker disease. II. Neurofibrillary tangles and plaques with PrP-amyloid coexist in an affected family.

Azzarelli et al reported an Indiana kindred affected by a hereditary disorder, characterized clinically by ataxia, parkinsonism, and dementia. Recently, we studied neuropathologically the 3rd and 4th cases that came to autopsy among the patients of this family. As in 2 patients examined previously, amyloid plaques were widespread throughout the cerebrum and the cerebellum, whereas neurofibrillary tangles were numerous in the cerebral cortex, the hippocampus, and the substantia innominata. Amyloid plaques were not recognized by polyclonal antibodies against the Alzheimer's disease amyloid A4 protein, but did contain epitopes recognized by antibodies against a prion protein. Spongiform changes were occasionally observed and were mild. Our findings indicate that this familial disorder is a form of or is related to Gerstmann-Sträussler-Scheinker disease. The consistent presence of numerous neurofibrillary tangles may be important in differentiating a distinct subgroup of patients with familial Gerstmann-Sträussler-Scheinker disease, and indicates that a disturbance of the cytoskeleton might be part of the neuronal pathology of Gerstmann-Sträussler-Scheinker disease.

Clinical significance of types of cerebellar amyloid plaques in human spongiform encephalopathies.

We report three patients with both spongiform encephalopathy and cerebellar amyloid plaques; one showed kuru-like plaques and was diagnosed as having Creutzfeldt-Jakob disease (CJD), and two had multicentric plaques and were diagnosed as having Gerstmann-Sträussler-Scheinker disease (GSSD). Evaluation of these cases and review of others previously reported suggests a clinicopathologic correlation between type of cerebellar plaque and neurologic clinical course. CJD patients who showed kuru-like plaques generally had disease with early onset (average age, 49.1 years) and long duration (average, 34 months), as compared with CJD patients without kuru-like plaques. GSSD patients usually had multicentric cerebellar plaques, and cases were usually familial, had early age of onset (average, 42.7 years), and were of long duration (average, 73 months). Myoclonus was infrequent in GSSD patients and pathologically spongiform change was minimal; spinal tract degeneration was common.

CNS amyloid proteins in neurodegenerative diseases.

The amyloid plaques found in neurodegenerative diseases show considerable morphologic diversity. Two amyloidogenic proteins have been isolated from the brains of humans and animals with neurodegenerative diseases--beta-protein from Alzheimer's disease (AD) and Down's syndrome, and prion protein (PrP) from scrapie and Creutzfeldt-Jakob disease (CJD). Using monoclonal antibodies to a synthetic peptide corresponding to a portion of beta-protein and rabbit antiserum to hamster scrapie PrP 27-30, we examined in situ amyloid plaques on sections from cases of neurodegenerative diseases, including cases with a spectrum of plaque types. Anti-beta-peptide stained cerebrovascular and plaque core amyloid in all AD cases as well as cerebrovascular amyloid and senile plaque core amyloid in five elderly CJD cases. Anti-PrP stained plaques in CJD, kuru, and Gerstmann-Sträussler syndrome cases but not cerebrovascular amyloid or plaques in AD. Dual localization experiments showed that in cases with a mixture of plaque types, the antibodies identified different populations of plaques that showed anatomic heterogeneity. Colocalization of the two proteins was not observed in any plaque type. The data suggest that in neurodegenerative diseases two major plaque types exist, which have different etiologic origins. Our results emphasize the need for classification of CNS amyloids based not on their morphology but on the macromolecular components comprising these pathologic polymers.

Familial dementia with PrP-positive amyloid plaques: a variant of Gerstmann-Sträussler syndrome.

We present a 22-year follow-up of a large and unusual kindred previously reported as familial Alzheimer's disease (FAD). However, detailed clinical and neuropathologic evaluation of family members and brain autopsy on another affected individual now make the diagnosis of FAD unlikely. Our patient, as well as members of this family, had numerous amyloid plaques and rare neurofibrillary tangles. These plaques were quite atypical for Alzheimer's disease (AD); many were quite large (up to 500 microns in diameter) and contained several amyloid cores, some with neuritic components. The plaques were present throughout the cerebral cortex and striatum, but not in the cerebellum. By electron microscopy, they had radiating star-shaped amyloid cores containing 8- to 10-nm fibrils, and a few dystrophic neurites. They were strongly immunoreactive with antiserum to prion protein but did not react with the antiserum to the amyloid A4 protein of AD. Although the cerebellum was uninvolved, this family appears to represent another clinical and neuropathologic variant of Gerstmann-Sträussler syndrome.