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Invasive Stage (invasive + stage)

Distribution by Scientific Domains

Medical Sciences	42%
Life Sciences	42%

Selected Abstracts

Differential transcriptome profiling identifies Plasmodium genes encoding pre-erythrocytic stage-specific proteins

MOLECULAR MICROBIOLOGY, Issue 5 2004
Karine Kaiser
Summary Invasive sporozoite and merozoite stages of malaria parasites that infect mammals enter and subsequently reside in hepatocytes and red blood cells respectively. Each invasive stage may exhibit unique adaptations that allow it to interact with and survive in its distinct host cell environment, and these adaptations are likely to be controlled by differential gene expression. We used suppression subtractive hybridization (SSH) of Plasmodium yoelii salivary gland sporozoites versus merozoites to identify stage-specific pre-erythrocytic transcripts. Sequencing of the SSH library and matching the cDNA sequences to the P. yoelii genome yielded 25 redundantly tagged genes including the only two previously characterized sporozoite-specific genes encoding the circumsporozoite protein (CSP) and thrombospondin-related anonymous protein (TRAP). Twelve novel genes encode predicted proteins with signal peptides, indicating that they enter the secretory pathway of the sporozoite. We show that one novel protein bearing a thrombospondin type 1 repeat (TSR) exhibits an expression pattern that suggests localization in the sporozoite secretory rhoptry organelles. In addition, we identified a group of four genes encoding putative low-molecular-mass proteins. Two proteins in this group exhibit an expression pattern similar to TRAP, and thus possibly localize in the sporozoite secretory micronemes. Proteins encoded by the differentially expressed genes identified here probably mediate specific interactions of the sporozoite with the mosquito vector salivary glands or the mammalian host hepatocyte and are not used during merozoite,red blood cell interactions. [source]

Subungual melanoma: Histological examination of 50 cases from early stage to bone invasion

THE JOURNAL OF DERMATOLOGY, Issue 11 2008
Miki IZUMI
ABSTRACT Subungual melanoma is a rare form of malignant melanoma. It is extremely difficult to differentiate it histologically from benign melanonychia striata or melanocytic nevus, especially in the early stage. We divided 50 cases of subungual melanoma into four groups according to clinical progress, and examined their histological findings in each respective stage. In the early stage (19 cases), atypical melanocytes were polygonal showing slight nuclear atypia with no mitoses at all. In six out of 19 cases (31.6%), the atypical melanocytes proliferated more in the hyponychium than in the nail matrix, and only very few in the nail bed. Periungual pigmentation (Hutchinson's sign) appeared from the early stage in almost all cases. With stage progression (middle stage, 13 cases; progressive stage, 13 cases; and bone invasive stage, five cases) the number of atypical melanocytes and their degree of nuclear atypia increased, and the ascent of atypical melanocytes and pagetoid spread became conspicuous. Mitoses became apparent only from the progressive stage. From these observations, we would like to propose three new pathological clues of early stage subungual melanoma: (i) "skip lesion", proliferation of the tumor cells are more prominent in the hyponychium than in the nail bed or nail matrix; (ii) histological confirmation of Hutchinson's sign; and (iii) epithelial thickening and/or compact arrangement of the elongated basal cells. [source]

Depression, anxiety and body image after treatment for invasive stage one epithelial ovarian cancer

AUSTRALIAN AND NEW ZEALAND JOURNAL OF OBSTETRICS AND GYNAECOLOGY, Issue 6 2009
Karin C. H. M. BISSELING
Background:, Diagnosis of epithelial ovarian cancer (EOC) in young women has major implications including those to their reproductive potential. We evaluated depression, anxiety and body image in patients with stage I EOC treated with fertility sparing surgery (FSS) or radical surgery (RS). We also investigated fertility outcomes after FSS. Methods:, A retrospective study was undertaken in which 62 patients completed questionnaires related to anxiety, depression, body image and fertility outcomes. Additional information on adjuvant therapy after FSS and RS and demographic details were abstracted from medical records. Both bi- and multivariate regression models were used to assess the relationship between demographic, clinical and pathological results and scores for anxiety, depression and body image. Results:, Thirty-nine patients underwent RS and the rest, FSS. The percentage of patients reporting elevated anxiety and depression (subscores , 11) were 27% and 5% respectively. The median (interquartile range) score for Body Image Scale (BIS) was 6 (3,15). None of the demographic or clinical factors examined showed significant association with anxiety and BIS with the exception of ,time since diagnosis'. For depression, post-menopausal status was the only independent predictor. Among those 23 patients treated by FSS, 14 patients tried to conceive (seven successful), resulting in seven live births, one termination of pregnancy and one miscarriage. Conclusion:, This study shows that psychological issues are common in women treated for stage I EOC. Reproduction after FSS is feasible and led to the birth of healthy babies in about half of patients who wished to have another child. Further prospective studies with standardised instruments are required. [source]

Type II fatty acid synthesis is essential only for malaria parasite late liver stage development

CELLULAR MICROBIOLOGY, Issue 3 2009
Ashley M. Vaughan
Summary Intracellular malaria parasites require lipids for growth and replication. They possess a prokaryotic type II fatty acid synthesis (FAS II) pathway that localizes to the apicoplast plastid organelle and is assumed to be necessary for pathogenic blood stage replication. However, the importance of FAS II throughout the complex parasite life cycle remains unknown. We show in a rodent malaria model that FAS II enzymes localize to the sporozoite and liver stage apicoplast. Targeted deletion of FabB/F, a critical enzyme in fatty acid synthesis, did not affect parasite blood stage replication, mosquito stage development and initial infection in the liver. This was confirmed by knockout of FabZ, another critical FAS II enzyme. However, FAS II-deficient Plasmodium yoelii liver stages failed to form exo-erythrocytic merozoites, the invasive stage that first initiates blood stage infection. Furthermore, deletion of FabI in the human malaria parasite Plasmodium falciparum did not show a reduction in asexual blood stage replication in vitro. Malaria parasites therefore depend on the intrinsic FAS II pathway only at one specific life cycle transition point, from liver to blood. [source]

Gallbladder cancer: a morphological and molecular update

HISTOPATHOLOGY, Issue 2 2009
Robert David Goldin
Gallbladder cancer (GBC) shows a marked geographical variation in its incidence, with the highest figures being seen in India and Chile and relatively low levels in many Western countries. Risk factors for its development include the presence of gallstones, infection and the presence of an anomalous pancreatobiliary ductal junction. It can arise from either a pathway involving metaplasia or dysplasia or one in which there is a pre-existing adenoma. The former is the more common and, because it is often not associated with a macroscopically recognizable lesion, leads to the recommendation that all gallbladders need to be examined microscopically. Accurate staging of invasive cancers is essential to determine prognosis and treatment, and this requires extensive tumour sampling. A number of genetic alterations have been identified in the preinvasive and invasive stages of GBC and they support the morphological evidence of there being two pathways by which tumours develop. Some of these genetic changes are associated with particular risk factors. For example, cases with anomalous pancreatobiliary ductal junction show a higher frequency of K-ras mutations. Some changes are associated with differences in prognosis. For example, cancers without expression of p21 but with expression for p27 have a better prognosis, whereas those that express c-erb-B2 have a worse one. Work has also been done on identifying clinical, imaging and other factors that indicate that patients have a higher risk of having GBC. This is particularly important in high-incidence areas in which GBC is a significant public health problem. [source]

Proteomic comparison of four Eimeria tenella life-cycle stages: Unsporulated oocyst, sporulated oocyst, sporozoite and second-generation merozoite

PROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 19 2009
Kalpana Lal
Abstract We report the proteomes of four life-cycle stages of the Apicomplexan parasite Eimeria tenella. A total of 1868 proteins were identified, with 630, 699, 845 and 1532 found in early oocysts (unsporulated), late oocysts (sporulated), sporozoites and second-generation merozoites, respectively. A multidimensional protein identification technology shotgun approach identified 812 sporozoites, 1528 merozoites and all of the oocyst proteins, whereas 2-D gel proteomics identified 230 sporozoites and 98 merozoite proteins. Comparing the invasive stages, we find moving junction components RON2 in both, whereas AMA-1 and RON4 are found only in merozoites and AMA-2 and RON5 are only found in sporozoites, suggesting stage-specific moving junction proteins. During early oocyst to sporozoite development, refractile body and most "glideosome" proteins are found throughout, whereas microneme and most rhoptry proteins are only found after sporulation. Quantitative analysis indicates glycolysis and gluconeogenesis are the most abundant metabolic groups detected in all stages. The mannitol cycle "off shoot" of glycolysis was not detected in merozoites but was well represented in the other stages. However, in merozoites we find more protein associated with oxidative phosphorylation, suggesting a metabolic shift mobilising greater energy production. We find a greater abundance of protein linked to transcription, protein synthesis and cell cycle in merozoites than in sporozoites, which may be residual protein from the preceding massive replication during schizogony. [source]

Rhoptries are major players in Toxoplasma gondii invasion and host cell interaction

CELLULAR MICROBIOLOGY, Issue 4 2007
Jean François Dubremetz
Summary Rhoptries are unique secretory organelles shared by all Apicomplexan invasive stages. They are exocytosed upon host cell invasion and their contents are involved in creating the moving junction that propels the parasite in the cell and in building the parasitophorous vacuole in which the parasite will develop. In addition, some rhoptry proteins are targeted to the host cell nucleus. The array of roles played by these organelles has considerably expanded in the recent years, making them a major clue to the understanding of the early interaction between these parasites and their host. Yet, our knowledge on these organelles is still very poor and much has to be done before we get a clear view of the part they play in Apicomplexan biology. [source]