Warthin''s tumour: unusual vs. common morphological findings in fine needle aspiration biopsies

Fine needle aspiration biopsies (FNA) of 47 Warthin's tumours confirmed by histology were re-evaluated for cytomorphological findings. The majority of aspirates (37/47) contained a typical background with proteinaceous substance and cell debris, along with cellular elements represented by oncocytic, lymphoid, and mast cells with degranulated cytoplasm. Uncommon cellular findings were true squamous cells (1/47), atypical cells with vacuoles (1/47), osteoclastic giant cells (1/47), epithelioid cells (1/47), mast cells with preserved granules in cytoplasm (3/47), and siderophages (4/47). Uncommon findings in the background were corpora amylacea-like structures and homogeneous bright red droplets. Squamous cells and atypical cells with vacuoles caused diagnostic difficulties in distinguishing a Warthin's tumour from a squamous cell or mucoepidermoid carcinoma. However, other unusual cellular and background findings were not worrying; therefore, they are merely regarded as a curiosity in the cytomorphological appearance of the tumour.     

Reduction of conductance-based neuron models

We present a scheme for systematically reducing the number of differential equations required for biophysically realistic neuron models. The techniques are general, are designed to be applicable to a large set of such models and retain in the reduced system as high a degree of fidelity to the original system as possible. As examples, we provide reductions of the Hodgkin-Huxley system and the A-current model of Connor et al. (1977).     

Selective cloning of hybridoma cells for enhanced immunoglobulin production using flow cytometric cell sorting and automated laser nephelometry

Techniques for selective cloning of murine hybridoma cells by flow cytometric cell sorting and use of automated laser nephelometry to determine the resultant clones' immunoglobulin secretion levels are described. Using a commercially available attachment to a fluorescence-activated cell sorter, individual hybridoma cells were successfully distributed into microtiter wells in an automated manner based on their forward angle light scatter properties and their reaction to fluorescein-conjugated anti-mouse-IgG. The techniques were used to estimate successfully the frequency of immunoglobulin-secreting cells in established cultures. In addition, heterogeneity of cell surface immunoglobulin expression was observed and utilized as a criterion for flow sorting of new hybridoma variants. In these studies, clones derived from high (anti-IgG) intensity sorting regions yielded cultures with enhanced immunoglobulin secretion levels, as determined by automated laser nephelometry. Furthermore, the surface immunoglobulin phenotype of the derived clones was conserved in subsequent progeny. Finally, it was established that inclusion of propidium iodide in the hybridoma cell sorting mixtures improved cloning efficiency by facilitating enhanced discrimination and elimination of nonviable cells. Our results indicate that flow cytometric-assisted single cell deposition provides positive attributes of several traditional hybridoma cloning techniques and, in addition, furnishes a tool for steering the cloning process toward selection of enhanced immunoglobulin producing cultures.     

Low molecular weight C1q-precipitins in hypocomplementemic vasculitis-urticaria syndrome: partial purification and characterization as immunoglobulin.

A lupus-like syndrome involving chronic urticaria with cutaneous vasculitis, systemic symptoms, hypocomplementemia with preferential depletion of C1q, and low m.w. (7S) C1q-precipitins has recently been defined. The C1q-precipitin activity (C1q-p) seems to represent a diagnostic marker of the disease, but its chemical nature is not yet clear. We have partially purified and characterized C1q-p from the serum of two patients with this syndrome and compared its activity with the C1q-precipitating activity of aggregated human gamma-globulin (AHGG) anti-C1q antibodies, and several polynucleotides including DNA and polyinosinic acid. C1q-p was found to partition with IgG during precipitation by ammonium sulfate and low ionic strength buffer as well as during column chromatography on DEAE-cellulose and G-200 Sephadex. Like AHGG, but in complete contrast to the polynucleotides, the C1q-precipitating activity of C1q-p was sensitive to pepsin, trypsin, and acidic conditions, but unaffected by DNAse or RNAse; the C1q-precipitating activity of anti-C1q antibody was not diminished by any of these procedures. Thus, C1q-p consists of gamma-migrating protein of low m.w., and its C1q-precipitating activity is indistinguishable from that of AHGG. These results are consistent with the concept that C1q-p is comprised, at least in part, of IgG that binds C1q via the Fc portion of the molecule.     

Water in the Avian Egg Overall Budget of Incubation

The loss of mass in eggs during incubation was examined andevidence is presented to show that this is essentially due toloss of water. The mean fraction of water lost by diffusionthroughout incubation is 0.150 ± 0.025 S D per gram ofegg and 0.162 ± 0.026 S D per gram of egg content for81 species. The water fraction of fresh eggs and of hatchingeggs was examined in 32 species divided according to maturityat hatching, and found to be very similar within each category(83% in altricial 83% in semi-altricial 78% in semi-precocial72% in precocial eggs). The 11% difference between the altricialand precocial categories is statistically significant. Duringincubation, dry matter is metabolized increasing the water fractionwhich is further increased by metabolic water production. Hence,water loss during incubation is mandatory if the relative watercontent of an egg at the end of incubation is to remain essentiallythe same as at the beginning. Equations are developed whichallow one to estimate the difference between diffusive waterloss and the total water loss in altricial and piecocial eggscaused by additional water loss during pipping and hatching.     

Gas Exchange of the Avian Egg Time, Structure, and Function

Data are presented for oxygen consumption water loss duringincubation water vapor conductance of the shell and pore numberof avian eggs and the way in which these values relate not onlyto egg mass but also to incubation time. It is proposed thatall these functions are proportional to the product of egg massand rate of development where the latter is defined as the inverseof incubation time. These interrelationships account at theend of incubation for similar O₂ and CO₂ tensions in the airspace of eggs utilization of calories (0.5 kcal g^–1) andwater loss (15 g g^–1)     

Modification of high molecular weight plasmic degradation products of human crosslinked fibrin.

The predominant high molecular weight products of plasmic digestion of human crosslinked fibrin Fragments DD, E and (DD)E complex were purified by column gel filtration in a non-dissociating buffer or by ion-exchange chromatography on DEAE-cellulose. The structure of the degradation products was studied by proteolytic degradation, polyacrylamide gel electrophoresis immunodiffusion and sucrose density gradient centrifugation. Unaltered derivatives were very resistant to proteolytic degradation by plasmin. In the the presence of 10 mM EDTA the (DD)E complex did not dissociate, but similar to Fragment DD, became susceptible to plasmic degradation forming Fragment D derivatives. The (DD)E complex dissociated in 3 M urea at pH 5.5, had an altered conformation as evidenced by its aggregability and by its increased susceptibility to degradation by plasmin resulting in the formation of Fragment d. The gammagamma chain remnants of Fragment DD were attacked first, followed by cleavage of the beta chain remnants. It is concluded that plasmin resistance is a function of the intact structure and it is not directly dependent on the presence of the crosslink bonds or calcium ions.     

Synthesis of symmetric and unsymmetric 1,4-bis(p-R-phenylethynyl)benzenes via palladium/copper catalyzed cross-coupling and comments on the coupling of aryl halides with terminal alkynes

A series of symmetric 1, 4-bis(p-R-phenylethynyl)benzenes (6a-h) have been prepared via Pd¹¹/Cu¹ catalyzed cross- coupling of 1, 4-diiodobenzene (5) and p-substituted phenylethynes (4a-h). Similarly, the unsymmetric analogues (9a-c) were obtained from 1-iodo-4-(p-nitrophenylethynyl)benzene (8) and p-substituted phenylethynes (4c, 4d, 4g). Quantitative analysis of 1,4-(trimethylsilyl)butadiyne (10), produced in the catalytic coupling of ethynyltri- methylsilane with aryl halides using PdCl₂(PPh₃)₂/CuI in an amine solvent, confirmed that catalyst initiation proceeds via reduction of Pd¹¹ to Pd⁰ with concomitant oxidative homo-coupling of two ethynyltrimethylsilane molecules producing exactly one equivalent of 10 based on Pd¹¹. If air is present, the PdCl₂(PPh₃)₂/CuI/amine mixture provides a very effective system for catalytic oxidative homo-coupling of terminal alkynes to diynes and thus air must be rigorously excluded from the cross-coupling reactions. Hydrodehalogenation can compete effectively with the cross-coupling reaction for highly fluorinated aryl halides. Under certain conditions, the fluorinated aryl bromide or iodide can serve as the oxidant for the alkyne to diyne oxidative homo-coupling reaction. This can be avoided by appropriate choice of reaction conditions and reagents. These competing pathways have significant implications for the cross-coupling of aryl halides with terminal alkynes and are discussed herein.