Stimuli for acquired resistance to Heligmosomoides polygyrus from intestinal tissue resident L3 and L4 larvae

L3 and L4 stages of H.polygyrus were prevented from developing further and were probably killed within 24 h of treatment with ivermectin although total parasite burdens, particularly when treatment was given 4-6 days after infection, declined over a longer period lasting several days. Strong resistance to challenge infection was expressed by infected mice dosed with ivermectin during the tissue phase of larval development. Even immunizing infections as brief as 12-36 h (when only L3 larvae would have been present in the mucosa) elicited strong acquired immunity. When infections were terminated 4-6 days after infection, acquired resistance was 95-100%. The stronger resistance of mice exposed to both L3 and L4 stages was associated with the recognition of low molecular weight polypeptides in adult worm homogenate and there was a highly significant correlation between percentage protection and anti-L4/anti-adult worm serum IgG1 antibodies.     

Unusual properties of mitochondria from the human term placenta are caused by alkaline phosphatase

Human placental mitochondria prepared by a new isolation procedure exhibit low but well coupled rates of state 3 respiration with different substrates (succinate: 32.3 nmol O2/mg/min, RCI = 4.4; pyruvate: 12.6 nmol O2/mg/min, RCI R = 4.2; palmitoylcarnitine: 16.6 nmol O2/mg/min, RCI R = 4.9). The addition of the uncoupler FCCP increased the respiratory rates (succinate: 40.7 nmol O2/mg/min; pyruvate: 21.2 nmol O2/mg/min: palmitoylcarnitine: 25.4 nmol O2/mg/min). The low respiratory rates correlate well with a low capacity of the respiratory chain as shown by the specific contents of cytochrome c (0.15 nmol/mg), cytochrome b (0.19 nmol/mg) and cytochrome oxidase (0.14 nmol/mg) as well as with the low content of adenine nucleotides (2.71 nmol/mg). These data together with the finding of high activities of alkaline phosphatase (2.2 U/mg) support the view that human placental mitochondria are contaminated with nonmitochondrial membranes. Since it was not possible to obtain functionally intact mitochondria with negligible activities of alkaline phosphatase the influence of this enzyme on the extramitochondrial adenine nucleotide turnover was investigated. Alkaline phosphatase splits phosphate from ATP, ADP and AMP with different rates resulting in an intermediate accumulation of AMP. Mitochondrial adenylate kinase (0.16 U/mg) regenerated ADP from AMP and ATP resulting in drastically decreased ADP/O ratios and prolonged state 3 respirations. Inhibiting the adenylate kinase with diadenosine pentaphosphate the ADP regeneration from AMP and ATP was suppressed which, in turn, enhanced the ADP/O ratios. In the absence of magnesium ions, if both the alkaline phosphatase and the adenylate kinase are inhibited normal ADP/O ratios and state 3-state 4 transitions can be observed. Under these conditions, human placental mitochondria showed normal properties comparable to those of mitochondria from other tissues with the only exception of low specific activities.     

Spray Drying: Retention of Volatile Compounds Revisited

Retention or loss of trace volatile compounds during spray drying can be vital for product quality. Examples of cases where loss or retentions of volatile substances are important include retention of balanced flavor and aroma in food products, removal of odiferous substances, and control of the release of volatile organic compounds to the atmosphere. Factors and mechanisms determining losses of these substances are reviewed. Losses can occur during atomization, from undisturbed drops and as a result of morphological development. On the basis of this insight, several avenues for controlling the retention of volatile substances are identified and analyzed. These include control of atomizer pressure or rotation speed, choice of spray angle, configuration of air input, lteration of the air temperature profile, feed concentration, the presence of an oil phase and/or suspended solids, foaming of the feed, feed composition, and steam blanketing of the atomizer.

The quality of a spray-dried product can be strongly affected by the presence or absence of volatile compounds that were present in the feed to the spray dryer. For example, spray-dried coffee and tea have suffered from a air and thereby avoid bubble formation, expansion and bursting for deaerated feeds (20). This approach produces a product with high bulk density. If that result is cceptable, then it should also be a way of precluding volatiles loss due to morphological development.     

Monoclonal antibodies recognizing epitopes on the extracellular face and intracellular N-terminus of the human erythrocyte anion transporter (band 3) and their application to the analysis of South East Asian ovalocytes

This report describes the production and characterization of 13 rodent monoclonal antibodies to the human erythrocyte anion transport protein AE1 (syn. band 3). Eleven antibodies (4 murine and 7 rat) recognize epitopes dependent on the integrity of the third extracellular loop of the protein. Two antibodies (1 murine and 1 rat) recognize epitopes on the N-terminal cytoplasmic domain. Quantitative binding studies using radioiodinated IgG and Fab fragments of antibodies to extracellular epitopes on AE1 ranged from 77,000 to 313,000 (IgG) and from 241,000 to 772,000 (Fab) molecules bound at saturation. The results indicate that the epitopes recognized by different antibodies vary in their accessibility and suggest that there is heterogeneity in the organization of individual AE1 molecules in the red blood cell membrane. Quantitative binding studies on South East Asian ovalocytes using several antibodies to AE1 and an anti-Wrb show a marked reduction in the number of antibody molecules bound at saturation. These results are consistent with the existence of highly cooperative interactions between transmembrane domains of AE1 in normal erythrocytes and the disruption of these interactions in the variant AE1 found in South East Asian ovalocytes.     

Giant desmosomes in tumors

The lengths of desmosomal profiles were measured in sections of tumor tissue from cases of mesothelioma, adenocarcinoma, squamous cell carcinoma, thymoma, and meningioma. Giant desmosomes (length of profile 1 micron or greater than 1 micron) were found in all the above-mentioned tumors except adenocarcinomas. The largest desmosomal profile in adenocarcinoma was approximately 0.8 micron long; the largest in mesothelioma was approximately 2 microns long. Our observations suggest that one of the ways in which giant desmosomes arise is by growth and fusion of adjacent desmosomes. Giant desmosomes may at times help in distinguishing mesothelioma from adenocarcinoma, but this is a rather rare phenomenon. In this study giant desmosomes were found in only 2 out of 10 cases of mesothelioma.     

HEASUREHENT OF INSTANTANEOUS RATES OF LOSS OF VOIATILE COMPOUNDS DURING DRYING OF DROPS

A novel technique serves to monitor instantaneous rates of loss of a volatile solute from a suspended drop during drying. A highly sensitive electron capture detector is used to monitor concentrations of SF6 released into a flowing gas stream from a suspended, drying drop. Simultaneously, the appearance and morphological development of the drop are monitored with a video camera. This provides the wherewithal of relating instantaneous rates of loss of the volatile solute to particular events during the development of particle morphology.

Initial experiments have been carried out with drops of aqueous solutions of glucose, sucrose, maltodextrin and coffee extract. The results clearly display the onset of the volatiles-retentive selective diffusion phenomenon. There is also substantial loss of the volatile component later in the drying process, when the drops undergo repeated ex ansion, bursting and cratering due to the formation of internaf bubbles. These experiments appear to be the first quantitative demonstration of major losses accompanying changes in drop morphology.