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Biomedical subjects

Claudia Lengerke

Publications and source records attributed to Claudia Lengerke.

7 recordsLinked to original sources
PubMed2006

Histocompatible embryonic stem cells by parthenogenesis.

Genetically matched pluripotent embryonic stem (ES) cells generated via nuclear transfer or parthenogenesis (pES cells) are a potential source of histocompatible cells and tissues for transplantation. After parthenogenetic activation of murine oocytes and interruption of meiosis I or II, we isolated and genotyped pES cells and characterized those that carried the full complement of major histocompatibility complex (MHC) antigens of the oocyte donor. Differentiated tissues from these pES cells engrafted in immunocompetent MHC-matched mouse recipients, demonstrating that selected pES cells can serve as a source of histocompatible tissues for transplantation.

Animals↗
PubMed2006

Cytomegalovirus pneumonia after stem cell transplantation: correlation of CT findings with clinical outcome in 30 patients.

OBJECTIVE: The purpose of our study was to assess the correlation between early high-resolution CT findings of cytomegalovirus (CMV) pneumonia in patients with blood disorders and their clinical outcomes. CONCLUSION: The initial high-resolution CT findings in immunocompromised patients with CMV pneumonia seem to predict the patient's outcome being unfavorable in those forms of disease beginning mostly bilaterally as diffuse or patchy ground-glass opacity followed by progressive air-space consolidation. Also, a change in the CT morphology of pulmonary lesions toward diffuse ground-glass opacity seems to correlate with an unfavorable disease course.

Adult↗
PubMed2005

Initial CT manifestations of invasive pulmonary aspergillosis in 45 non-HIV immunocompromised patients: association with patient outcome?

PURPOSE: To assess early high-resolution computer tomographic (CT) signs of invasive pulmonary aspergillosis (IPA) in non-HIV immunosuppressed patients and their potential association with patient's outcome, including frequency and severity of pulmonary hemorrhage, taking also in consideration the impact of other known risk factors contributory to IPA. MATERIAL AND METHODS: A retrospective review of serial CT scans was performed in 45 immunocompromised patients with a total of 46 episodes of invasive pulmonary aspergillosis. All patients underwent CT beginning with the day they showed clinical or laboratory signs of infection. Serial follow-up CT included more than two, up to 12 CT examinations. Patient's outcome was judged by clinical and radiological follow-up and classified as survival, death by IPA, or death unrelated to IPA. The influence of patient's age, underlying disease, hematopoietic stem cell transplantation, neutropenia, graft versus host disease, and antifungal therapy onset was also statistically considered. RESULTS: Three main CT findings were identified: small nodules (<1cm) 43% (20/46), large nodules 21% (10/46) and consolidations, either in patchy+/-segmental 26% (12/46), or peribronchial distribution+/-tree in bud 9% (4/46). In 11 patients (24%) we found a combination of two or more of these signs: 9 (19%) patients presented concurrent small nodules accompanied by reticulation, tree in bud or peribronchial infiltrates, while 2 (4%) patients showed large pulmonary nodules accompanied by large consolidations. An accompanying "halo" sign was observed in 38 patients (82%). Crescent sign followed by cavitation was encountered in 29 patients (63%). Two patients succumbed to massive pulmonary bleeding caused by IPA. Twenty-one patients (15/46) deceased in this series, 12 of them succumbed to IPA, 1 died from cerebral invasive aspergillosis, while in 9 patients the cause of death was not primarily IPA. Manifest pulmonary hemorrhage occurred in 19% (9/46) of IPA episodes. CONCLUSION: Initial CT findings of invasive pulmonary aspergillosis consist mainly of small nodules or patchy consolidations, showing in 82% of cases an early halo sign. Serious pulmonary hemorrhage was an infrequent clinical complication in our series, with an attributable mortality of 4.3%. IPA-related lethality was 26%, in our cohort. None of the early HRCT signs seemed to predict outcome.

Adolescent↗
PubMed2005

Significance of the "halo" sign for progression and regression of nodular pulmonary amyloidosis: radiographic-pathological correlation (2005:6b).

We describe a case of a systemic amyloidosis of kappa-AL type, presenting at CT as focal lung parenchymal nodules or areas of consolidation with or without a halo,showing different sizes and morphologic kinetics at follow-up. Lesions accompanied by a halo revealed faster progression and earlier response to chemotherapy with almost complete resolution after high dose therapy with a cytostatic alkylating agent(Melphalan) and autologous peripheral stem cell transplantation than their counterparts without a halo. Amyloid deposition was histologically confirmed, and severe inflammatory activity was found in and at the margins of the amyloidomas, the latter correlating in CT with the halo sign. In our case, this sign had a high prediction for growth kinetics and response to therapy of pulmonary amyloid.

Amyloid↗
PubMed2005

Patterning definitive hematopoietic stem cells from embryonic stem cells.

Derived from the inner cell mass of blastocysts, embryonic stem cells (ESCs) retain the pluripotent features of early embryonic epiblast cells. In vitro, ESCs undergo spontaneous differentiation into a multitude of tissues, and thus are a powerful tool for the study of early developmental processes and a promising resource for cell-based therapies. We have pursued the derivation of functional, multipotent and engraftable hematopoietic stem cells (HSCs) from ESCs in order to investigate the genetic pathways specifying blood formation, as well as to lay the foundation for hematopoietic cell replacement therapies based on engineered ESCs. Theoretically, the generation of HSCs from patient-specific ESCs derived by nuclear transfer could provide for autologous hematopoietic therapies for the treatment of malignant and genetic bone marrow disorders. Although significant progress has been made in achieving hematopoietic differentiation from both murine and human ESCs, we have only a primitive understanding of the underlying mechanisms that specify hematopoietic cell fate, and a very limited capacity to direct the differentiation of the definitive HSC that would be suitable for clinical engraftment studies. Here we will review the progress to date and the significant problems that remain, and outline a strategy to achieve the directed differentiation of HSCs under conditions that might be appropriate for clinical scale-up and disease applications.

Animals↗
PubMed2002

Improved detection of splenosis in patients with haematological disorders: the role of combined transmission-emission tomography.

The purpose of this study was to evaluate the use of combined transmission and emission tomography (TET) for correct localisation of heterotopic splenic tissue and differentiation of splenosis from other masses. The TET technique comprises the fusion of SPET and CT data obtained using the same imaging device to allow perfect overlap of anatomical and functional images. TET was performed in seven patients who either had haematological disorders and relapsing anaemia or thrombocytopenia after splenectomy or were under immunosuppression for different reasons. These patients presented 20 equivocal lesions on CT or MRI. Presence of splenic tissue was investigated using technetium-99m labelled colloids or heat-damaged red blood cells. Findings of spleen scintigraphy, TET and CT or MRI were compared with respect to localisation of splenosis and correct classification of lesions by CT or MRI. Histological validation was achieved by surgery or biopsy in all cases. All 20 lesions demonstrated by CT or MRI were correctly classified by TET as splenosis. Three additional lesions initially overlooked by CT or MRI could be detected. Diagnostic relevance was highest for intrahepatic, intrapulmonary or pleural splenic implants. It is concluded that TET allows exact localisation of heterotopic splenic tissue in patients with suspected splenosis.

Adult↗