Disruption of microtubules as an early sign of irreversible ischemic injury. Immunohistochemical study of in situ canine hearts

Structural disruption of the cytoskeleton may be involved in irreversible ischemic injury. In the present study, ischemic changes in microtubules during various periods of myocardial ischemia were studied with an immunohistochemical technique in open-chest dogs. In intact myocardium, microtubules were stained as a filamentous network throughout cytoplasm and a circular network around the nucleus, which disappeared with colchicine treatment. In brief ischemia of less than 15 minutes, microtubule patterns were unaltered. After 20 minutes, however, characteristic microtubule stains were partly lost in patchy lesions. As an increase in ischemic period, lesions of loss of microtubule stains were increased in number and size. After 120 minutes of reperfusion following 60 minutes of ischemia, the lesions with intact actin filaments but with disrupted microtubules were replaced by the severely injured cells in which the regular myofibrillar registrations were distinctly disrupted. After 24 hours of reperfusion following 40 minutes of occlusion of the left circumflex artery, the percent area of disrupted microtubules at 40 minutes of ischemia was replaced by that of irreversibly injured lesions in the posterior papillary muscle. These results indicate that disruption of microtubules during ischemia heralds irreversible ischemic injury. However, in in vitro study, the myocardium incubated in hypoxic solution for 60-120 minutes demonstrated earlier disruption of the microtubules than the vinculin. Electron microscopic study also showed minimal irreversible changes in the lesions with disrupted microtubules. Thus, taken together, we conclude that microtubules that support the structural integration of myofibrils and other organelles are disrupted in severe myocardial ischemia before the irreversible injury, promoting the irreversible change after reperfusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Significance of the contribution of aerobic and anaerobic components to several distance running performances in female athletes

To assess the most important determinant for successful distance running (800 m, 1500 m and 3000 m events) in female athletes, measurements of several anaerobic indices were made (peak power, mean power) using the Wingate anaerobic test (WAnT), and aerobic indices such as oxygen uptake (VO2) or running velocity (v) at lactate threshold (LT), VO2 or v at onset of blood lactate accumulation (OBLA), running economy (RE), and maximal oxygen uptake were determined using the incremental treadmill test. The RE was represented by a VO2 value measured at 240 m.min-1 of a standard treadmill velocity. A stepwise multiple regression analysis (SAS stepwise procedure) combined the best features of forward inclusion and backward elimination to determine the most important factors in predicting the performance of running these distances as dependent variables. The stepwise procedure showed that the blood lactate variables such as LT and/or OBLA are highly correlated with, and contributed to predicting performance running 800 m-3000 m, whereas the anaerobic component was related only to running 800 m. In conclusion, blood lactate variables account for a large part of the variation in distance running performance in female as in male runners. The component of the anaerobic system which can be measured by the WAnT was shown to contribute to performance in running 800 m, but not in longer distances.

The role of Na+/H+ exchange in norepinephrine-induced protein synthesis in neonatal cultured rat cardiomyocytes

It is reported that Na+ influx contributes to stretch-induced cardiac hypertrophy. Na+ influx may also be involved in cardiac hypertrophy induced by catecholamine. In the present study, to test whether Na+/H+ exchange plays an important role in norepinephrine-induced cardiac hypertrophy, the effect of Na+/H+ exchange inhibitor, amiloride on protein synthesis was studied in cultured neonatal rat cardiomyocytes in serum free medium. [3H]Phenylalanine uptake was determined 24 and 48 hours after administration of norepinephrine with and without amiloride. In the control, norepinephrine increased [3H]phenylalanine uptake in a dose dependent manner (10(-5)-10(-7) M). Prazosin (10(-7) M) and amiloride (10(-5)-10(-4) M) significantly attenuated the norepinephrine mediated protein synthesis. These results indicate that alpha 1-adrenergic stimulation enhances the protein synthesis through activation of Na+/H+ exchange. Therefore, Na+ influx and/or PH increase may play a key role in cardiac hypertrophy.

[Ferruginous bodies in the lungs of the general population during a 45-year period and mineralogical examination]

In order to determine the level of asbestos pollution in the lungs of members of the general population in and around Tokyo, the incidence of ferruginous bodies in autopsied or resected lungs during 5 periods over the 45 years from 1937 to 1981 was studied by a light microscopy. Core fibres, after removal of their ferruginous coatings with oxalic acid, and uncoated fibres were analyzed using a scanning electron microscope equipped with a Kevex energy-dispersive X-ray spectrometer. The incidence of ferruginous bodies in 5 g (wet) of digested lung tissue was shown to be 10% in period I (1937-1941), 18% in period II (1947-1951), 70% in period III (1958-1963), 74.4% in period IV (1970-1973) and 81.0% in period V (1980-1981). The major types of core fibres of ferruginous bodies were found to be asbestos, including amosite, crocidolite, chrysotile and the tremolite-actiolite series, but a small number of fibers of materials other than asbestos were also detected. In contrast, a large number of short fibers less than 5 microns in length in 1 g of wet lung tissue were classified as belonging to Mg + Si fibers (the ratio of Mg to Si components being 30% or over) and presumed to be chrysotile. Thus an annual increase in asbestos deposition in lungs of people living in and around Tokyo has been demonstrated and fine chrysotile fibers less than 5 microns in length seem to be the main type of deposited fibers.

Effect of a histidine-excess diet on a tetrahydrofolylpolyglutamate pattern in rat liver

The effect of a histidine-excess diet on the hepatic folylpolyglutamate pattern in rat was studied. Rats were fed ad libitum 9.7% casein basal diets with 0.6% methionine (controls) or the basal diets with 3.5% histidine. The average daily weight gain and the food intake in histidine-supplemented rats (His-rats) did not significantly differ from controls. The liver weight in His-rats, however, was 50% higher than controls. Hepatic methyltetrahydropteroylpentaglutamate (CH3-H4PteGlu5), and tetrahydropteroylmonoglutamate concentrations in His-rats was 5.7- and 2-fold higher than controls, respectively. The tetrahydropteroylpentaglutamate (H4PteGlu5) concentration in the His-rats was 74% lower than controls. Considering the homeostasis of folate cofactors in tissues, these results suggest that the hepatic regeneration systems for H4PteGlu5 in His-rats might be repressed and an apparent methylfolate trap might be attained rather on a pteroylpentaglutamate level than a monoglutamate level, and that the activity for catabolizing the excess histidine might exceed the regenerating activity for folate cofactors.

[Stress analysis of bridge abutment teeth with cemented dowels]

Stress analysis of bridge abutment teeth having cemented dowels was conducted using a two-dimensional finite element method. The results obtained are as follows: 1. In fixed-fixed bridges, compressive stress was found concentrated within the dowel, on the mesial side of the dowel apex, and in the distocervical part of the crown. 2. In cantilever bridges, tensile stress was found concentrated in the disto-occlusal and mesiocervical parts of the crown, and along the mesial sides of the root and the dowel. Compressive stress was concentrated in the distocervical part of the crown, along the distal sides of the root and dowel, and on the mesial side of the dowel apex. 3. In comparison with fixed-fixed bridges, stresses were significantly greater in cantilever bridges in the abutment teeth, the dowel, and crown margins. 4. In both fixed and cantilever bridges, stresses increased in relation to the length of the span. The rate of increase was less, however, in fixed-fixed than cantilever bridges.

Tumor uptake of [48V]vanadyl-chlorine e6Na as a tumor-imaging agent in tumor-bearing mice

[48V]Vanadyl-chlorine e6Na (48V-Chl) which was synthesized by insertion of 48V (positron emitter) into chlorine e6Na (Chl), a chlorophyll derivative having a similar structure to pheophorbide-a (Pheo), localized rapidly in experimental mammary carcinoma. The tumor-to-organ ratios of 48V-Chl were higher than those of 48V-labeled Pheo (48V-Pheo), and 48V-Chl showed a clear tumor image with low accumulation in liver, depending on the biodistribution of metal-free Chl having an affinity with tumor. 48V-Chl seems to be more suitable than 48V-Pheo as a tumor-imaging agent for photodynamic therapy of tumors.

A case of Fabry's disease in a patient with no alpha-galactosidase A activity caused by a single amino acid substitution of Pro-40 by Ser

We analyzed a male patient with Fabry's disease who had no activity of the lysosomal hydrolase alpha-galactosidase A (alpha-GalA) and female members of his family. We cloned a cDNA that encoded the mutant alpha-GalA, determined its nucleotide sequence, and found two nucleotide differences between the mutant and the wild-type cDNAs. Although one difference was silent, the other difference, a C-to-T transition at nucleotide number 118, resulted in an amino acid substitution of Pro-40 by Ser. A transient expression assay demonstrated that this missense mutation was the cause of the deficiency of alpha-GalA activity in the patient. In vitro mutagenesis experiments demonstrated that Pro-40 is critical for the appearance of alpha-GalA activity.

An epidemiologic and histopathological study of sudden cardiac death in Osaka Medical Examiner's Office

From 1982 to 1986, 1230 sudden death cases were autopsied in Osaka Medical Examiner's Office. Among them, 810 cases were sudden cardiac deaths (SCD) including coronary heart disease (77%), cardiomyopathy (7%), valvular disease (3%). All SCD cases were dead within 24 hours of the appearance of the fatal symptoms, and most of them (72%) were considered instantaneous death. Many of the fatal symptoms began in bed (31%), at bath (17%), at toilet (8%), or at work (8%). Thirty-four percent of them were thought by themselves or by their families to be healthy before the death. Hypertension (38%), coronary heart disease (13%) and diabetes mellitus (11%) were the major past history recorded. Microscopic observation of the hearts of 200 cases autopsied in 1986 showed various cardiac lesions: hypertrophy, atrophy, degenerations of myocytes, cellular and fatty infiltrations of the interstitium. According to their cardiac lesions and degrees of severity of coronary sclerosis, patients who died suddenly were divided into 8 groups as follows: 1. myocardial infarction (41) 2. myocarditis (6) 3. hypertrophic cardiomyopathy (19) 4. chronic ischemia with severe coronary sclerosis (65) 5. chronic ischemia with moderate coronary sclerosis (27) 6. small vessel disease (18) 7. amyloidosis (1) 8. unknown (23). These results suggest that coronary heart disease and hypertension play an important role in SCD.

Possible different mechanisms of B cell activation in systemic lupus erythematosus and rheumatoid arthritis: opposite expression of low-affinity receptors for IgE (CD23) on their peripheral B cells

To clarify the differential state of B cell activation in patients with systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA), we investigated the expression of low-affinity receptor for IgE (Fc epsilon RII; CD23) on their peripheral B cells by a cytofluorometry using H107 (CD23) and Leu-16 (CD20) monoclonal antibodies. The percentage of CD23-negative B cells in total lymphocytes was significantly greater in both groups of patients than in normal subjects, suggesting the hyperactivity of late-phase B cells in both diseases. However, the increase of CD23-negative B cells in RA was brought about by the increased number of total B cells, although that in SLE was mainly based on the relative decrease of CD23-positive B cells. The number of IgD-positive B cells was decreased, and the number of colony-forming B cells was markedly increased in SLE patients. These observations indicate that a B cell abnormality is mainly qualitative in SLE but quantitative in RA.

Physiological determinants of race walking performance in female race walkers

The purpose of this study was to determine the relationship between race pace on a 5 km walking performance and velocity at the lactate threshold (V-LT), VO2 at the lactate threshold (VO2-LT), velocity at which blood lactate corresponded to 4 mM level (V-OBLA), VO2 at which blood lactate corresponded to 4 mM level (VO2-OBLA), walking economy (steady state VO2 at a standard velocity) and maximal oxygen uptake (VO2max) in eight female race walkers. A multiple stepwise linear regression analysis was employed to predict the race pace on a 5 km walking performance as dependent variable. Since V-OBLA was highly correlated to 5 km race walking performance (r = 0.94, P less than 0.001), it was selected as the first predictor. When VO2max was added to V-OBLA as the second predictor the predictive accuracy increased significantly, but multiple R did not increase significantly by adding variables of walking economy or other parameters as independent variance. As a result, the combination of V-OBLA and VO2max as independent variables accounted for the greatest amount of total variance (97 per cent). It is suggested that blood lactate variable such as V-OBLA can account for a large portion of the variance in race pace on a 5 km walking performance.

Human spleen histone H1. Isolation and amino acid sequences of three minor variants, H1a, H1c, and H1d

Following the previous determination of the main variant H1b of human spleen histone H1, we have determined the complete amino acid sequence of another variant, H1d. Limited chymotryptic digestion of H1d produced four fragments, I to IV, and one partial fragment I-II, as in the case of H1b. These fragments were aligned with two overlapping peptides, produced by another enzyme from the intact H1d. We also confirmed the C-terminal sequence of H1d by carboxypeptidase digestion. This H1d has an acetylated N-terminal serine, equimolar alanine or valine residue at 17, and is composed of 212 residues. The molecular weight was 21,233 for the alanine variant and 21,261 for the valine variant in the unmodified form. We also deduced the total sequences of H1a and H1c in a similar way, considering the maximum homology with H1b and H1d. Each N-terminal serine residue is acetylated, too. H1a consists of 222 amino acid residues and has a molecular weight of 22,178 in its unmodified form; the H1c consists of 220 residues and has a molecular weight of 22,218 in that form. The human spleen H1 sequences varied to about the same extent in the N-terminal 40 and C-terminal 110 residues. However, the sequences of the about 70 internal residues are well conserved between the variants. The extent of differences among the human H1 variants is similar to, or rather smaller than, those among the mammalian somatic H1 species. The implications of these differences in the sequence for H1 function are discussed from the evolutionary viewpoint.

[Immunohistochemical study of idiopathic bronchiolitis obliterans organizing pneumonia]

To examine the characteristics of idiopathic BOOP and to compare them with those of organizing pneumonia (OP) with known causes, immunohistochemical examinations using monoclonal antibodies against T- and B-lymphocytes which are available for formaldehyde-fixed and paraffin-embedded sections, and polyclonal antibodies against human IgG, IgA and IgM, and bovine S-100 protein, were carried out, along with conventional histopathological examinations. Histopathological observations demonstrated that both of the 7 BOOP cases and 5 OP cases had polypoid masses of organizing tissue in the lumen of small airways, alveolar ducts, and some alveolar sacs, and infiltration of pulmonary interstitium by a large number of lymphocytes and moderate number of plasma cells, eosinophils and mast cells. Degree of bronchiolo-alveolitis was greater in idiopathic BOOP. Immunohistochemically, the majority of lymphocytes which had diffusely infiltrated into the interstitium were T-lymphocytes, the degree of which was higher in the cases of BOOP. On the other hand, B-lymphocytes were seen mainly in the lymphoid follicles. Furthermore, S-100 protein positive dendritic cells were noted in the lymphocyte rich interstitium in the all cases of both groups, and similarly between two groups. Immunoglobulin (Ig) positive plasma cells were also seen, but there was no evidence indicating the preferential increase of plasma cells which produce a particular class of Ig. These observations suggest that there might be some immunological mechanisms in the pathogenesis of BOOP in which T-lymphocytes, mast cells and eosinophils are involved.

Introduction and expression of the human insulin gene in adult rat liver

Liposomes associated with gangliosides and loaded with the human insulin gene were incubated with HVJ (Sendai virus) and red blood cell membranes containing non-histone chromosomal protein, high mobility group 1 (HMG-1), or bovine serum albumin (BSA) to form vesicle complexes. These vesicle complexes were then injected into the portal vein of adult rats. The insulin gene co-introduced with HMG-1 was transported into the nuclei of liver cells much more efficiently than the gene co-introduced with BSA. Moreover, the amount of transcript of the insulin gene co-introduced with HMG-1 was more than 10 times greater than that of the gene co-introduced with BSA. Similar amounts of DNA and RNA of human insulin were found in the liver within 7 days after injection of the gene, and then the amounts of both decreased rapidly. The level of human insulin in rat serum gradually increased to a maximum (20-30 microunits/ml) after 7 or 8 days and then decreased rapidly.

Adenosine-induced hyperemia attenuates myocardial ischemia in coronary microembolization in dogs

We have recently reported that coronary microembolization sustains myocardial ischemia with hyperemic response of coronary blood flow (CBF) induced by massive release of adenosine from the ischemic myocardium. In this study, we tested the hypothesis that this hyperemic flow caused by released adenosine improves myocardial ischemia. In eight dogs (control), microspheres (5.0 X 10(4)/ml of base-line CBF) were repetitively injected until CBF decreased toward zero, and the changes in CBF, fractional shortening, lactate extraction ratio (LER), and adenosine release were studied. In 15 other dogs, an identical procedure was done with an intracoronary infusion of prazosin (4 micrograms.kg-1.min-1, n = 8) or theophylline (0.1 mg.kg-1.min, n = 7) to elucidate the effect of adenosine, since prazosin inhibits release of adenosine from ischemic myocardium and theophylline blocks adenosine receptors. In 16 other dogs, hemodynamic and metabolic parameters were examined with and without these drugs after a single injection of microspheres (1.0 X 10(5)/ml of base-line CBF). In the control group, CBF increased to 170 +/- (SE) 14% of the base-line CBF at 16-30% of maximal embolization. In contrast, intracoronary infusion of prazosin markedly attenuated adenosine release and hyperemic response and significantly deteriorated both fractional shortening and LER. Theophylline also significantly attenuated the hyperemic response and tended to decrease both fractional shortening and LER. A salutary effect of adenosine release was further confirmed by the improvement of ischemic changes in the same dog after withdrawal of prazosin and theophylline associated with an increase in CBF. Thus we conclude that adenosine released from ischemic myocardium improves ischemia in microembolization through the hyperemic response.

[Three-dimensional reconfirmation of the gingivo-periosteal microvasculature and its angiogenesis during the healing process]

Periodontal surgical procedures are conducted largely on the basis of the angiogenic and fibrogenic activity of the periosteum. Therefore, it is considered that correlating treatment with this healing activity of the periosteum is a key to a successful outcome. The purpose of the present study was to reconfirm the periosteal microvasculature in the periodontal region, and closely observe the role of the vasculature in wound healing and its angiogenesis during the healing process by means of a vascular corrosion cast. In 30 adult mongrel dogs with healthy periodontium, the basic morphology of the periosteal vasculature was observed, with the left maxillary attached gingiva and alveolar mucosal regions serving as a control. A 6 x 6 mm incision was made in the right attached gingiva in order to remove a layer of not slear at a predetermined position, and the healing process was observed on the 5th, 7th, 14th, 21st, and 28th postoperative day. A difference in histological construction between the gingiva and the alveolar mucosa was observed in the vasculature, which enabled easy distinction of muco-gingival junction from the periosteal vasculature. In addition, the fact that the gingivo-periosteal vasculature served as a base for vigorous angiogenesis associated with gingival regeneration and bone resorption and formation was made clear when a layer of partial thickness was removed.

An increase in myocardial beta-adrenoceptors to compensate for postischaemic dysfunction following coronary micro-embolisation in dogs

This study examined whether beta-adrenoceptors increase in number during recovery from prolonged myocardial stunning and whether they compensate for lack of physiological response to beta-adrenergic stimulation in this abnormality. The left coronary artery was embolished in anaesthetised dogs with non-labelled microspheres (15 +/- 1 micron; 1.2 X 10(6).kg-1 body weight). Haemodynamic studies were performed before (control) and 24 h and 1 week after embolisation, in the conscious state. Myocardial noradrenaline content, plasma catecholamine concentrations and the density of beta-adrenoceptors (Bmax) were also assessed at three study intervals. At 24 h after embolisation, both systolic and diastolic cardiac function was significantly depressed. The inotropic response to isoprenaline was preserved, but the response to forskolin was markedly depressed. One week after embolisation, resting systolic function was restored to control levels and histological examination showed absence of myocardial necrosis. Although plasma noradrenaline concentration had returned to normal, myocardial noradrenaline content had decreased by 36% and the density of beta-adrenoceptors had increased by 48%. Myocardial relaxation was still impaired and the inotropic response to forskolin was also still depressed, whereas the response to isoprenaline was normal. Moreover, the down regulation of the increased beta-adrenoceptors by isoprenaline infusion for 24 h unmasked the latent systolic dysfunction. These results indicate that the density of beta-adrenoceptors increases during the recovery process from prolonged myocardial stunning and that this increase may compensate, at least in part, for impairment of the inotropic mechanism distal to the beta-adrenoceptors.

Evidence for an intraluminal mediator in rat pancreatic enzyme secretion: reconstitution of the pancreatic response with dietary protein, trypsin and the monitor peptide

New evidence has been obtained suggesting that the "monitor" peptide is an essential intraluminal mediator in the stimulation of pancreatic enzyme secretion in response to protein intake in rats. Experiments were performed in vivo using a mixture of 50 mg of ovalbumin, alpha-lactalbumin or casein, 2 micrograms of purified protease-sensitive, cholecystokinin-releasing monitor peptide and 1 mg of porcine trypsin which was infused by cannula into the duodenum of atropine-treated rats. The small intestine had previously been washed with bicarbonate to eliminate proteases and the pancreatic juice was diverted. The amount of trypsin secreted in 2 h was comparable to that of rats in which the pancreatic juice was returned into the duodenum. However, in the presence of a monitor peptide--specific antibody which recognizes the N-terminal region of the peptide, the monitor peptide did not induce any pancreatic response. Therefore, the characteristic pattern of pancreatic enzyme secretion in response to protein intake can be reproduced by infusing only three components--dietary proteins, porcine trypsin and the purified monitor peptide.

Role of alpha 1-adrenoceptor activity in progression of cardiac hypertrophy in guinea pig hearts with pressure overload

To elucidate the role of alpha 1- and beta-adrenergic activities in pressure overload hypertrophy, changes of alpha 1- and beta-adrenoceptors were measured by radioligand binding assay, and the preventive effects of alpha 1- and beta-adrenoceptor blockade on cardiac hypertrophy were assessed in guinea pigs after aortic banding. Five days after banding, dry weight of left ventricle had not increased, though wet weight increased due to marked intercellular oedema. In this period, the maximum binding capacity of [3H] prazosin increased to 31.1 (SEM 2.2) fmol.mg-1 from (sham operation) 17.0(2.1) fmol.mg protein-1, p less than 0.01, whereas the maximum binding capacity of [3H]dihydroalprenolol did not increase: 143(16) fmol.mg-1 (banded) v 153(13) fmol.mg-1 (sham). Three weeks after aortic banding, the maximum binding capacity of both ligands increased to 45.6(5.5) fmol.mg-1 and 232(21) fmol.mg-1, respectively, accompanied by a significant increase in left ventricular dry weight, from 0.46(0.02) mg.g-1 (sham) to 0.62(0.08) mg.g-1 (banded), p less than 0.01. Continuous subcutaneous administration of the alpha 1-blocker bunazosin (0.1 mg.kg-1.d-1) significantly attenuated the increase in left ventricular dry weight whereas the beta-blocker propranolol (5 mg.kg-1.d-1) did not: 0.55(0.03) v 0.66(0.04) mg.g-1 respectively, after 3 weeks. These results show that pressure overload elicited an increase in myocardial alpha 1-adrenoceptors before the onset of cardiac hypertrophy, and that an alpha 1-blocker could prevent the development of hypertrophy in the pressure overloaded heart.

Tetrahymena HMG nonhistone chromosomal protein. Isolation and amino acid sequence lacking the N- and C-terminal domains of vertebrate HMG 1

The complete amino acid sequence of a high mobility group (HMG) nonhistone chromosomal protein of the ciliated protozoan Tetrahymena pyriformis (GL strain) was determined. This protein was extracted with 0.5 M HClO4 together with histone H1 (molar ratio 1:1) from the whole histone extract, then purified by gel filtration and reverse-phase HPLC. The HMG protein showed a single electrophoretic band on SDS gel electrophoresis. The amino acid sequence was determined by Edman degradation of intact protein, BrCN fragments, and their staphylococcal protease and tryptic peptides. Thus the total sequence, consisting of 99 amino acid residues and having a molecular weight of 11,626, was completely determined. Phosphorus analysis of the tryptic peptides, containing serine or threonine, showed that this HMG protein was phosphorylated at two positions, each 6-7%, and contained 0.15 mol phosphate/mol protein. This Tetrahymena HMG is rather similar to the central part of vertebrate HMG 1 in terms of the amino acid sequence and the hydropathy profile.

In vivo binding of the winged bean basic lectin labeled with iodo[2-14C]acetic acid to the intestinal epithelial cells of the rat

Winged bean basic lectin was labeled with iodo[2-14C]acetic acid. The radiolabeling affected neither the antigenicity nor the hemagglutinating activity of the lectin. A liquid test meal consisting of [14C]lectin and an unabsorbable marker, [3H]polyethylene glycol (PEG), was administered to rats in order to investigate behavior of the lectin in the gastrointestinal tract. At 1 h after administration, 54% of the administered [14C]lectin was still in the stomach, 1% had reached the cecum, and 1-6% was found in the intestinal mucosa, indicating that the lectin was binding to the mucosa. In another experiment, rats were fed a commercial nonpurified diet for 3 d after administration of the test meal. About 87% of the administered lectin as well as 83% of [3H]PEG was recovered from the feces during these 3d. Lectin bound to the epithelial cells of the intestinal mucosa was recovered by liberating it from the cells with D-galactose. The recovered lectin showed both hemagglutinating activity and the antigenicity identical with those of the original lectin. These results clearly indicated that the lectin remained intact in the gastrointestinal tract while a part of it was bound to the intestinal mucosa, the rest being excreted directly into feces.

Heterogeneity in terms of interleukin 4-dependent regulation of Fc epsilon...receptor/CD23 expression on chronic B-lymphocytic leukemia cells

To discriminate the stages of maturation arrest of leukemic B cells, we have investigated the cell surface expression of Fc epsilon RII (H107 antigen) on leukemic B cells from 6 patients with chronic type B-lymphocytic leukemia (B-CLL) by a double staining method combined with cytofluorometry, and their production of soluble Fc epsilon RII by an ELISA technique. Fc epsilon RII was expressed on mu+/delta- cells of case 5 as well as on mu+/delta+ cells of cases 1, 2 and 4, but not on mu+/delta+ cells in cases 3 and 6. The cultivation of leukemic cells with IL-4 not only increased the percentage of Fc epsilon RII+ cells but also enhanced the production of soluble Fc epsilon RII+ in most cases. However, IL-4 had no effects on mu+/delta-/Fc epsilon RII+ cells of case 5, which appeared to correspond to a rather late stage of normal B cell differentiation. Moreover, while leukemic B cells from case 1 spontaneously produced large amounts of soluble Fc epsilon R, the release seemed to be inhibited by an addition of IL-4. From our observations, it is speculated that IgM+/IgD+/Fc epsilon RII- leukemic B cells express surface membrane Fc epsilon RII and produce soluble Fc epsilon RII following stimulation with IL-4, and that IgM+/IgD-/Fc epsilon RII+ B-CLL cells may exist at some late stage of B cell differentiation.