Fine needle aspiration of Langerhans cell histiocytosis of the lymph nodes. A report of six cases

BACKGROUND: Fine needle aspiration (FNA) diagnosis of Langerhans cell histiocytosis (LCH) of the lymph nodes has been described rarely. CASES: LCH was confined to the lymph nodes in six children. The FNA smears showed high cellularity composed of many isolated Langerhans cells (LCs) with nuclear grooves and intranuclear inclusions. Also seen were numerous eosinophils, lymphocytes, giant cells, dendriticlike cells, macrophages and Charcot-Leyden crystals in a background of eosinophilic granules. Immunohistochemical study revealed a positive reaction with S-100 protein. CONCLUSION: The presence of LCs with nuclear grooves, eosinophils, giant cells and a positive reaction with S-100 protein aided the diagnosis of LCH of the lymph nodes. Charcot-Leyden crystals, intranuclear inclusions and dendriticlike cells were seen in this study. These findings have not been reported before in lymph node FNA smears of LCH.     

Cytology of leukemic lymphadenopathy

OBJECTIVE: To describe the cytomorphologic features of leukemic cells in lymph node aspiration material. STUDY DESIGN: We studied lymph node fine needle aspiration (FNA) smears of 36 leukemic patients. In 23 cases the lymphadenopathy was noticed simultaneously with marrow leukemia, and in the other 13 cases the lymphadenopathy was noticed during a relapse. Special stains, such as periodic acid Schiff, Sudan Black-B, Oil Red-O and nonspecific esterase, were used in special cases. RESULTS: Thirty-three cases were diagnosed as lymphoma, 1 as extramedullary hematopoiesis and 2 as leukemic involvement. CONCLUSION: Leukemic lymphadenopathy can be misdiagnosed as lymphoma on FNA smears. The clinical findings, previous history, hematologic studies and immunocytochemical studies are essential to the differentiation of leukemic smears from lymphoma. However, in some cases the leukemic infiltration can be diagnosed with certainty, provided that the smears show the characteristic findings, such as Auer rods and neoplastic promyelocytes with azurophilic granules.     

Intraoperative cytologic crush preparation findings in craniopharyngioma: a study of 72 cases

OBJECTIVE: To describe the intraoperative crush preparation and the cytologic features of craniopharyngioma and the differential diagnosis. STUDY DESIGN: Twelve cases of craniopharyngioma were diagnosed by crush preparation cytology in the Department of Pathology, Shiraz Medical School, and formed the basis of this study. The patients' ages ranged from 7 to 43 years; 3 were female and 9 male. The cytologic findings together with the histologic findings were studied. RESULTS: All cases had a high yield of cells, consisting of honeycomb sheets of epithelial cells with and without palisading rows of cells, papillary clusters, squamous cell clusters, anucleated squames, calcification, multinucleated giant cells, cholesterol crystals, glandular or rosettelike structures, ciliated columnar cells and spindle cells. The smears were diagnosed as suggestive of craniopharyngioma. Histologic sections confirmed the cytologic diagnoses. CONCLUSION: Intraoperative cytologic crush preparation findings are helpful in the diagnosis of craniopharyngioma, when combined with clinical information. Crush preparation cytology is important in the diagnosis of central nervous system tumors.     

Parental care trade‐offs in the inter‐brood phase in Barn Swallows Hirundo rustica

In seasonal environments with limited time and energy resources, double‐brooded birds face trade‐offs in the timing of their two reproductive attempts and in the effort allocated to the first and the second broods. In the Barn Swallow Hirundo rustica a long care period for the first brood enhances the survival of first‐brood chicks, but also delays the start of the second brood, which in turn reduces the survival prospects of second‐brood chicks. Probably as a response to this trade‐off, double‐brooded Barn Swallows reduce the period of post‐fledging care for first‐brood fledglings. By radiotracking whole families, we investigated the determinants of this behaviour and its consequences for the survival of the first‐brood fledglings. The end of the females’ investment in post‐fledging care of the first brood was related to the beginning of egg synthesis for the second clutch. With the start of egg synthesis, females significantly reduced provisioning rates to the first‐brood fledglings to less than one‐fifth of the previous rates, while the proportion of time they spent foraging remained high. Assuming that the females’ foraging success was constant, we conclude that their energy income was allocated to egg production rather than fledgling provision. Males did not compensate for the females’ reduced feeding rates. Thus the start of egg production for the second clutch had a marked effect on the quantity of food received by first‐brood fledglings. In parallel with the changes in parental behaviour and provisioning rates, we observed a marked drop in the daily survival rate of first‐brood chicks. These results support the hypothesis that females face a strong trade‐off in the allocation of energy to subsequent broods. Energy allocation to a second clutch involves a cost in terms of reduced provisioning, and as a result the survival of first‐brood chicks is compromised. This is probably outweighed by the improved success of an early second brood.     

Small fragment homologous replacement-mediated modification of genomic beta-globin sequences in human hematopoietic stem/progenitor cells

An ultimate goal of gene therapy is the development of a means to correct mutant genomic sequences in the cells that give rise to pathology. A number of oligonucleotide-based gene-targeting strategies have been developed to achieve this goal. One approach, small fragment homologous replacement (SFHR), has previously demonstrated disease-specific genotypic and phenotypic modification after introduction of small DNA fragments (SDFs) into somatic cells. To validate whether the gene responsible for sickle cell anemia (beta-globin) can be modified by SFHR, a series of studies were undertaken to introduce sickle globin sequences at the appropriate locus of human hematopoietic stem/progenitor cells (HSPCs). The characteristic A two head right arrow T transversion in codon 6 of the beta-globin gene was indicated by restriction fragment length polymorphic (RFLP) analysis of polymerase chain reaction (PCR) products generated by amplification of DNA and RNA. At the time of harvest, it was determined that the cells generally contained 相似文献   

Atmospheric water vapor as driver of litter decomposition in Mediterranean shrubland and grassland during rainless seasons

Litter production in many drought‐affected ecosystems coincides with the beginning of an extended season of no or limited rainfall. Because of lack of moisture litter decomposition during such periods has been largely ignored so far, despite potential importance for the overall decay process in such ecosystems. To determine drivers and extent of litter decay in rainless periods, a litterbag study was conducted in Mediterranean shrublands, dwarf shrublands and grasslands. Heterogeneous local and common straw litter was left to decompose in open and shaded patches of various field sites in two study regions. Fresh local litter lost 4–18% of its initial mass over about 4 months without rainfall, which amounted to 15–50% of total annual decomposition. Lab incubations and changes in chemical composition suggested that litter was degraded by microbial activity, enabled by absorption of water vapor from the atmosphere. High mean relative humidity of 85% was measured during 8–9 h of most nights, but the possibility of fog deposition or dew formation at the soil surface was excluded. Over 95% of the variation in mass loss and changes in litter nitrogen were explained by characteristics of water‐vapor uptake by litter. Photodegradation induced by the intense solar radiation was an additional mechanism of litter decomposition as indicated by lignin dynamics. Lignin loss from litter increased with exposure to ultraviolet radiation and with initial lignin concentration, together explaining 90%–97% of the variation in lignin mass change. Our results indicate that water vapor, solar radiation and litter quality controlled decomposition and changes in litter chemistry during rainless seasons. Many regions worldwide experience transient periods without rainfall, and more land area is expected to undergo reductions in rainfall as a consequence of climate change. Therefore, absorption of water vapor might play a role in decomposition and nutrient cycling in an increasing number of ecosystems.     

Comparative transfection of DNA into primary and transformed mammalian cells from different lineages

Background  

The delivery of DNA into human cells has been the basis of advances in the understanding of gene function and the development of genetic therapies. Numerous chemical and physical approaches have been used to deliver the DNA, but their efficacy has been variable and is highly dependent on the cell type to be transfected.     

Evidence that the phytochrome gene family in black cottonwood has one PHYA locus and two PHYB loci but lacks members of the PHYC/F and PHYE subfamilies

The phytochrome photoreceptors play important roles in the photoperiodic control of vegetative bud set, growth cessation, dormancy induction, and cold-hardiness in trees. Interestingly, ecotypic differences in photoperiodic responses are observed in many temperate- zone tree species. Northern and southern ecotypes of black cottonwood (Populus trichocarpa Torr. & Gray), for example, exhibit marked differences in the timing of short-day-induced bud set and growth cessation, and these responses are controlled by phytochrome. Therefore, as a first step toward determining the molecular genetic basis of photoperiodic ecotypes in trees, we characterized the phytochrome gene (PHY) family in black cottonwood. We recovered fragments of one PHYA and two PHYB using PCR-based cloning and by screening a genomic library. Results from Southern analyses confirmed that black cottonwood has one PHYA locus and two PHYB loci, which we arbitrarily designated PHYB1 and PHYB2. Phylogenetic analyses which included PHY from black cottonwood, Arabidopsis thaliana and tomato (Solanum lycopersicum) suggest that the PHYB/D duplications in these species occurred independently. When Southern blots were probed with PHYC, PHYE, and PHYE heterologous probes, the strongest bands that we detected were those of black cottonwood PHYA and/or PHYB. These results suggest that black cottonwood lacks members of the PHYC/F and PHYE subfamilies. Although black cottonwood could contain additional PHY that are distantly related to known angiosperm PHY, our results imply that the PHY family of black cottonwood is less complex than that of other well-characterized dicot species such as Arabidopsis and tomato. Based on Southern analyses of five black cottonwood genotypes representing three photoperiodic ecotypes, substantial polymorphism was detected for at least one of the PHYB loci but not for the PHYA locus. The novel character of the PHY family in black cottonwood, as well as the differences in polymorphism we observed between the PHYA and PHYB subfamilies, indicates that a number of fundamental macro- and microevolutionary questions remain to be answered about the PHY family in dicots.