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General Pathology Jj Rippey Pdf [NEW] Download

The overall incubation period for VHF ranges from 2 to 21 days. There is a wide constellation of clinical manifestations with varying degrees of severity in patients infected with these viruses, and not all patients develop classic VHF syndrome. The exact nature of the disease depends on viral virulence, routes of exposure, dose and host factors. Patients with VHF generally have nonspecific symptoms such as fever, myalgia and prostration; clinical examination may show only conjunctival injection, mild hypotension, flushing and petechial hemorrhages. Illness caused by filoviruses, flaviviruses and Rift Valley fever (RVF) viruses tends to have an abrupt onset, whereas the pathology triggered by arenaviruses has a more insidious onset. For Lassa fever patients, hemorrhagic manifestations are not pronounced; and neurological complications are infrequent, develop late and manifest only in the most severely ill group. Deafness is a frequent long-term consequence of severe Lassa fever. For the South American arenaviruses, neurological and hemorrhagic manifestations are much more prominent. Hepatic involvement is common for all VHFs, but only a small percentage of patients with RVF, Crimean-Congo HF (CCHF), Marburg hemorrhagic fever, Ebola hemorrhagic fever and yellow fever manifest a clinical picture dominated by jaundice and other evidence of hepatic failure. VHF mortality may be substantial, ranging from 5% to 20% or higher in recognized cases. Ebola outbreaks in Africa have had particularly high case fatality rates, from 50% up to 90%3,4,5.

General Pathology Jj Rippey Pdf Download

Schizophrenia is a common yet devastating mentaldisorder characterized by a series of cognitive, behavioral andemotional dysfunctions, none of which are pathognomonic for thedisease. It includes both positive symptoms, mainly represented byhallucinations and delusions and negative ones, such as bluntedaffect, avolition and social isolation, along with disturbedattention, executive function and working memory (1). Structural changes in the brain (whitematter, grey matter, size) have been shown in controlledneuropathology leading to the idea that schizophrenia might be atrue psychosomatic disorder (2). Theonset is either abrupt or insidious, anywhere between lateadolescence and mid of the 4th decade, followed by an episodic anddeteriorating course, with every new episode worsening theprognosis (3,4). Genetic epidemiological studies suggestthat the life time risk of developing schizophrenia in generalpopulation is 0.5-1%, although it increases considerably whenrelatives with the disorder are present (5). Even though the established geneticcomponent of schizophrenia is high (heritability of 0.8), much ofits genetic architecture remains unknown (6). As many other complex psychiatricdisorders, for example the intrapsychic dissociative phenomenon(also genetically conditioned) (7),schizophrenia is a multifactorial disorder, which encompasses theinterplay of multiple susceptibility genes, epigenetic processesand environmental factors (8). Largestudies on de novo, common and rare variants pointed to manycausal aspects from the N-methyl-D-aspartate receptor signaling andpostsynaptic density (PSD), calcium channels, targets of micro-RNAmiR-137, glutamate pathways, processes related to neurogenesis andsynaptic integrity and yet there are many unknown pathogenicpathways in the etiology of schizophrenia (9-13)as well as linking neuroendocrine aspects during pregnancy andpostpartum life of the female patient affecting the new borndevelopment (14). We explored thecontributions to the understanding of schizophrenia genetics of theclassical twin and linkage studies, as well as the newer candidategene and genome-wide association studies (GWAS), with the impliedrisk loci and single nucleotide polymorphism (SNP) and thecritical, so-called copy number variation (CNV).

A study by Davis and Phelps (18) tries to investigate this unaccountedfor prenatal environment in twins, hypothesizing that monochorionicmonozygotic (MC-MZ) twins are more concordant for schizophreniathan dichorionic monozygotic (DC-MZ) twins. Their hypothesis is inaccord with the latest studies that show an increased risk ofschizophrenia for children exposed to infectious disease especiallyin the second trimester (20-22).Because there are no studies investigating placentation in twinsand the risk for schizophrenia, the authors used mirroredhandedness as a retrospective marker for placentation. Ifplacentation occurs within 4 days of fertilization, the twins willbe DC-MZ, developing separate placentas and chorions and almostalways separate circulations with the mother (23). However, if twining occurs after day4, the twins will be MC-MZ and will share fetal circulation in 90%of cases. Twinning after day 4 will result in mirror imaginglimited to the ectodermal layer and observed phenotypically asmirror hair swirls, dermal ridge patterns on hands and feet or handpreferences (24,25). Only mirror hand preference was usedas placentation marker in the study of 71 pairs of twins. Theretrospective marker of mirror handedness for placentation has afew shortcomings that decrease its statistical power: handedness isa characteristic that could be caused by other factors than latetwinning such as learning, brain pathology or perinatal stressorsand MC twins with same-handedness could be considered DC twins withsame handedness or vice versa confounding the study groups.Nevertheless, within the 71 case-study there were far moreopposite-hand twin pairs that developed schizophrenia or psychosis(9 out of 15 pairs, 60%) compared with the same hand preferencegroup (18 out of 56, 32.1%) (18).The low number of opposite-hand cases and the rate of MC twinningof generally 60% could mean that the opposite-hand group is in factMC twins. Likewise, the relatively high concordance (32.1%) forschizophrenia in the DC-MZ twins' group would imply that many ofthe second study group are MC-MZ same-handed twins (18). A way of validating these resultswould be a study with clear data for placentation, obtainedpost-partum; nonetheless, this study covers a mainly ignoredpossible source of schizophrenia in identical twins.


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