Cloned mouse cells with natural killer function and cloned suppressor T cells express ultrastructural and biochemical features not shared by cloned inducer T cells.

We have examined the morphology, cytochemistry, and biochemistry of mouse leukocyte subsets by analyzing cloned leukocyte populations specialized to perform different immunologic functions. Cloned cells expressing high-affinity plasma membrane receptors for IgE and mediating natural killer (NK) lysis and cloned antigen-specific suppressor T cells contained prominent osmiophilic cytoplasmic granules similar by ultrastructure to those of mouse basophils. Both clones also incorporated 35SO4 into granule-associated sulfated glycosaminoglycans, expressed a characteristic ultrastructural pattern of nonspecific esterase activity, incorporated exogenous [3H]5-hydroxytryptamine, and contained cytoplasmic deposits of particulate glycogen. By contrast, cloned inducer T cells lacked cytoplasmic granules and glycogen, incorporated neither 35SO4 nor [3H]5-hydroxytryptamine, and differed from the other clones in pattern of nonspecific esterase activity. These findings establish that certain cloned cells with NK activity and cloned suppressor T cells express morphologic and biochemical characteristics heretofore associated with basophilic granulocytes. However, these clones differ in surface glycoprotein expression and immunologic function, and the full extent of the similarities and differences among these populations and basophils remains to be determined.

Mast cell clones: a model for the analysis of cellular maturation.

Cloned mouse mast cells resemble, by ultrastructure, immature mast cells observed in vivo. These mast cell clones can be grown in the absence of any other cells, facilitating direct investigations of their biochemistry and function. We find that cloned mast cells express plasma membrane receptors (Fc epsilon R) that bind mouse IgE with an equilibrium constant (KA) similar to that of normal mouse peritoneal mast cells. In addition, cloned mast cells do not display detectable la antigens and cannot enhance lg secretion when added to lymphocyte cultures or mediate natural killer lysis. In the presence of 1 mM sodium butyrate, cloned mast cells stop dividing and acquire abundant electron-dense cytoplasmic granules similar to those of mature mast cells. Their histamine content increases concomitant with cytoplasmic granule maturation and may exceed that of untreated mast cells by 50-fold. Unlike peritoneal mast cells, cloned mast cells incorporate 35SO4 into chondroitin sulfates rather than heparin. These findings demonstrate that, unlike fully differentiated mouse peritoneal mast cells, cloned immature mouse mast cells contain no heparin and low levels of histamine. In addition, they establish that high-affinity Fc epsilon R are expressed early in mast cell maturation, well before completion of cytoplasmic granule synthesis and mediator storage.

The effect of rabeprazole on regional gastric acidity and the postprandial cardia/gastro-oesophageal junction acid layer in normal subjects: a randomized, double-blind, placebo-controlled study.

BACKGROUND: Postprandial intragastric acidity is not uniform. Postprandial proximal gastric acid pockets have been described in the present study. AIM: To determine the effects of rabeprazole on regional intragastric acidity and proximal acid pockets. METHODS: Ten normal subjects underwent two 8-day oral dosing regimens with placebo or rabeprazole 20 mg each morning in a randomized, double-blind protocol. Oesophago-gastric pH monitoring was performed on days 1 and 8. RESULTS: Rabeprazole increased fasting and postprandial gastric pH to above 4 in each area of the stomach on days 1 and 8. With placebo, acid pockets were identified at the cardia/gastro-oesophageal junction in 62 and 50 of 150 pull-throughs on days 1 and 8, respectively. Acid pockets were detected postprandially 3.1 +/- 0.2-5.8 +/- 0.1 cm below the proximal border of the lower oesophageal sphincter with a mean pH drop from 4.6 +/- 0.1 to 1.5 +/- 0.1. Rabeprazole decreased the number of acid pockets to 30 and 27 on days 1 and 8, respectively. Rabeprazole also decreased their length and magnitude of the pH drop. CONCLUSIONS: Rabeprazole increased intragastric pH on day 1 and 8 and maintained an elevated pH during and after meals. Postprandial acid pockets, identified in the region of the cardia/gastro-oesophageal junction area postprandially, were decreased in number, length and magnitude by rabeprazole.

Differential effects of sham feeding and meal ingestion on ghrelin and pancreatic polypeptide levels: evidence for vagal efferent stimulation mediating ghrelin release.

UNLABELLED: Ghrelin has been suggested to function as an appetite-stimulating signal from the gastrointestinal tract to the brain acting through a vagal afferent pathway. Ghrelin levels rise before meals and fall after meal ingestion. The purpose of this study was to investigate factors which regulate ghrelin release into the circulation by determining changes in systemic ghrelin concentrations after sham feeding and meal ingestion. METHODS: Fifteen normal subjects underwent sham feeding of a bacon and cheese toasted sandwich. Serial blood samples were obtained before and every 5 min for another 30 min during sham feeding and for 30 min after actual meal ingestion. Radioimmunoassay was used to measure plasma ghrelin and pancreatic polypeptide concentrations. RESULTS: During sham feeding, plasma ghrelin concentration increased from 1730+/-237 to 1917+/-269 pg/mL (P<0.05) and plasma pancreatic polypeptide increased from 417+/-50 to 841+/-97 pg/mL (P<0.01). Subsequent meal ingestion was characterized by an increase in pancreatic polypeptide from 782+/-88 to 1710+/-119 pg/mL (P<0.01), but no significant change in ghrelin levels. CONCLUSIONS: Plasma ghrelin and pancreatic polypeptide concentrations increase with sham feeding. This suggests a vagal efferent pathway mediating ghrelin release. In contrast to pancreatic polypeptide which rises with actual meal ingestion, ghrelin levels did not change.

[Cutaneous myiasis caused by a double infestation with larvae of Dermatobia hominis and Cochliomyia hominivorax]. / Cutane myiasis door een dubbelinfestatie met larven van Dermatobia hominis en Cochliomyia hominivorax.

In a 51-year-old man who had visited Surinam, cutaneous myiasis was diagnosed, caused by simultaneous infestation with the larvae of two different species of flies: Dermatobia hominis and Cochliomyia hominivorax. On his right lower arm the man had two solitary, furuncle-like lesions with a central breathing hole. Two days after these holes had been occluded with vaseline, two white larvae of D. hominis emerged. On both ankles the man had large, undermined ulcers containing hundreds of creeping larvae about 2 cm in length with a salmon-like colour: C. hominivorax. The larvae were removed from the ulcers by hand and by rinsing with physiological saline, after which the wounds healed rapidly. Myiasis is seen in the Netherlands mostly in people returning from a holiday in myiasis-endemic areas.

The role of serum phosphate level and acute ischemic bowel disease.

The objectives of this study were to determine whether an elevated serum phosphate level is predictive of acute ischemic bowel disease and whether it serves as a prognostic indicator in patients with intestinal ischemia. A retrospective chart review was performed at an urban teaching hospital emergency department. Twenty-three patients with documented acute ischemic bowel disease from 1990 through 1994 were compared with 27 patients with acute abdominal disease entities unrelated to intestinal ischemia. The sensitivity, specificity, and positive and negative predictive values of serum phosphate were 26%, 85%, 60%, and 58% respectively. Levels of phosphate in patients with intestinal ischemia versus controls were 4.20 versus 3.41 mg/dL (P = .1338). The length of bowel necrosis in the experimental group with elevated phosphate versus normal phosphate level was 57.53 cm versus 99.00 cm (P = .4132). Although not statistically significant, linear regression revealed slightly positive correlations in those with elevated phosphate versus normal phosphate level (in the experimental group) with the length of bowel necrosis and duration of hospital stay as r= .155 (P = .4813) and r= .134 (P= .5418), respectively. Serum phosphate level independently has no diagnostic or prognostic value in acute ischemic bowel disease.

Proteins synthesized by inducer T cells: evidence for a mitogenic peptide shared by inducer molecules that stimulate different cell types.

Inducer T lymphocytes synthesize and secrete peptides that stimulate growth and differentiation of many cell types, including lymphocytes and monocytes that kill foreign organisms, B lymphocytes, mast cells and hematopoietic precursor cells. To define these inducer molecules more precisely, we have generated clones of these T cells as a source of homogeneous material for biochemical analysis. These clones synthesize peptides that stimulate T and B cells to divide and that also induce the latter cells to secrete immunoglobulin. Inducer cells synthesize a 14 kilodalton growth polypeptide that stimulates T and B lymphocytes, as well as other cell types, to divide. This 14 kilodalton peptide is normally associated with different, larger peptides that appear to focus its mitogenic activity to one or another target cell.

Purified glial fibrillary acidic protein and desmin are distinct intermediate filament proteins exhibiting similar properties.

Glial fibrillary acidic (GFA) protein and desmin were purified from bovine brain and large intestine, respectively, and used in a comparison of the major protein components of two classes of intermediate filaments, the glial and smooth muscle filaments. The proteins are similar in size, charge, and amino acid composition, but clearly distinct. By sodium dodecyl sulfate-gel electrophoresis, GFA protein is about 5,000 daltons smaller than desmin. GFA protein is composed of three isoelectric variants which are all slightly more basic than the two variants observed for desmin. One-dimensional peptide mapping following limited proteolysis under denaturing conditions or following cyanogen bromide cleavage demonstrates that the proteins are not closely related in primary structure. Assembly-disassembly experiments reveal that the proteins share solubility properties and that negatively stained preparations of in vitro polymerized filaments are very similar. Limited proteolysis under native conditions demonstrates substructural similarities; comparative peptide mapping following digestion with chymotrypsin and trypsin suggests related core polypeptides of about 37,000 and 21,000 daltons. We conclude that GFA protein and desmin are distinct with respect to primary structure, but probably represent two of the more closely related classes of intermediate filament proteins.

Analysis of insulin-specific T cell clones. I. Strategy for production of clonotypic antibody.

A novel strategy for production of T cell clone-specific antiserum is described. Clones that are both antigen-specific and alloreactive can be injected in small numbers i.v. into a strain which expresses the appropriate alloantigens, inducing consistently high-titered antisera containing antibodies to the unique T cell receptor molecules on these cells. The antisera characterized in this report block activation of these cells by either antigen plus autologous class II products or alloantigen. Furthermore, in the absence of antigen, the antiserum strongly stimulates the specific clones to divide, and to synthesize and secrete various proteins. Consistent with the findings of other investigators, the antiserum immunoprecipitates a disulfide-linked dimer of 90,000 m.w. from the surfaces of cells with the appropriate specificity.

Bacteroides peritonitis associated with colon cancer in a continuous ambulatory peritoneal dialysis patient.

Peritonitis is not an uncommon complication of continuous ambulatory peritoneal dialysis (CAPD). We report a case of Bacteroides fragilis-induced bacterial peritonitis, probably due to clinically occult malignancy, in a 76-year-old woman on CAPD.

A cloned cell with NK function resembles basophils by ultrastructure and expresses IgE receptors.

Natural killer (NK) cells are defined by their ability to lyse certain tumour cells in vitro without previous exposure to them, and have been postulated as effectors of immune surveillance against spontaneous neoplasms. Because they kill some non-neoplastic lymphoid cells, they may also have a role in immunoregulation. NK cell activity resides in a small proportion of normal mouse spleen cells (less than 5%) that have been difficult to characterize completely. They may represent a heterogeneous group of effector cells whose precise relationship to other myelopoietic or immunological cells has remained obscure. We have previously described a cloned mouse cell line (Cl. Ly 1-2-NK-1+/11) with the functional characteristics of natural killer cells activated by interferon or other factors. We now find that this cloned line, like basophils and mast cells, expresses high-affinity plasma membrane receptors (Fc epsilon R) specific for IgE antibody. In addition, the clone contains cytoplasmic granules similar by ultrastructure to those of basophils of the mouse and other species. Our findings indicate that cells sharing morphological and biochemical features of basophilic granulocytes can mediate NK lysis.