Induction and the possible mechanism of ventricular tachycardia after catheter ablation with direct current shocks in dogs

Cathodal DC shocks (150-J) were administered via the His bundle to 20 closed-chest dogs, and in a further three dogs 25-J cathodal shocks were given via the left ventricular endocardium. In 18 dogs, including three that underwent left ventricular ablation, Holter electrocardiograms were recorded from 1 to 7 days after ablation, and 4 weeks after ablation. There were frequent episodes of sustained ventricular tachycardia (VT) from the first few hours after ablation to 4 days after ablation in all dogs, but both the rate and the coupling interval of VT were variable. In five conscious dogs stimulated 1 day after ablation, it was difficult to induce and terminate VT repeatedly. There was a direct relationship between the paced cycle length and the interval of the last paced beat to the initiating VT beat in three out of four dogs. In the fourth dog there was an inverse relationship. There was no transient entrainment with ventricular burst pacing during VT in any of the four dogs tested. The effects of lidocaine (2-3 mg.kg-1), verapamil (0.2-0.4 mg.kg-1), and propranolol (0.2 mg.kg-1) on VT were tested within 2 days of ablation in 10 conscious dogs. In general, both lidocaine and verapamil terminated VT, and propranolol slowed VT. In conclusion, VT soon after ablation possibly results from triggered activity, although abnormal automaticity cannot be ruled out.

Stimulatory effects of HSR-803 on ileal motor activity

Stimulatory effects of HSR-803 on intestinal motor activity in vitro were studied in guinea pig ileum. HSR-803 (1 x 10(-6)-1 x 10(-4) M) increased the amplitude of longitudinal muscle contractions and increased the frequency of peristalsis in isolated segments of guinea pig ileum. The stimulatory effect in amplitude and not frequency was abolished by 1 x 10(-6) M atropine. In the Magnus method with ileal segments, HSR-803 (1 x 10(-7) - 1 x 10(-4) M) produced contractions concentration-dependently, which were inhibited by atropine (1 x 10(-8) and 3 x 10(-8) M) and 3 x 10(-7) M tetrodotoxin (TTX). In the [3H]-quinuclidinyl benzilate (QNB) binding experiment with ileal smooth muscle, HSR-803 had low affinity for acetylcholine (ACh) receptors (pKi = 4.47 +/- 0.04). In addition, HSR-803 failed to increase the spontaneous release and the electrical stimulation-induced [3H]ACh release in ileal smooth muscle. On the other hand, HSR-803 (1 x 10(-5) M) enhanced contractions induced by ACh, but had no effect on contractions induced by carbachol, which is not hydrolyzed by acetylcholinesterase (AChE). In conclusion, HSR-803 stimulated ileal motor activity. However, HSR-803 had low affinity for ACh receptors and had no influence on ACh release. It is likely that HSR-803 stimulated motor activity mainly due to prevention of ACh hydrolysis.

Increased synthesis and specific localization of a major lysosomal membrane sialoglycoprotein (LGP107) at the ruffled border membrane of active osteoclasts

The immunocytochemical localization was investigated of a major lysosomal membrane sialoglycoprotein with a molecular mass of 107 kDa, which was designated as LGP107. The study utilized rat osteoclasts with different bone resorbing activity and osteoclast precursors at various stages of differentiation and maturation together with monospecific antibodies to this protein. Despite its localization primarily in lysosomes and endosomes in the other cell types examined, LGP107 was exclusively confined to the apical plasma membrane at the ruffled border of the active osteoclast, where the osteoclast is in contact with the bone surface. The protein was also concentrated in a number of endocytic vacuoles in the vicinity of the ruffled border membrane. However the labeling was not found in the basolateral membranes of the active osteoclast. The ruffled border membrane detached from the bone surface showed a marked decrease in the extent of the immunolabeling. The post- and/or resting osteoclasts, which were located away from the bone surface, were totally devoid of the membraneous localization of LGP107. No definite immunolabeling was found in the immature preosteoclasts. These results indicate that the protein is largely synthesized in the active osteoclast and rapidly translocated to the ruffled border membrane by vectorial vesicle transport. LGP107 is suggested to contribute to the formation and maintenance of the specialized acidic environment for bone resorption.

Characterization of four new cell lines derived from small-cell gastrointestinal carcinoma

Four human small-cell gastrointestinal carcinoma cell lines were established from tumor tissues of patients with esophageal, gastric or rectal cancer, and were studied morphologically and biochemically in comparison with small-cell lung carcinoma (SCLC) cell lines and common gastric cancer cell lines. Cells from all the small-cell gastrointestinal carcinoma lines were as small as classic SCLC cells and had characteristic neurosecretory granules. Cells from only one line grew as tightly packed spherical aggregates of floating cells, and those of the other 3 grew attached to substrate. Although high levels of creatine kinase brain isoenzyme (CK-BB) were detected in all 4 cell lines, 2 of them showed low levels of aromatic L-amino-acid decarboxylase and 3 had low levels of neuron-specific enolase (NSE). None of the lines showed simultaneous elevation of enzymes. C-myc, N-myc, and L-myc were not amplified in any of the cell lines, but c-myc mRNA was expressed in 2 lines. Our findings indicate that all small-cell gastrointestinal carcinoma cells examined belong to the variant type which is used in the classification of SCLC. Furthermore, the ECC18 line, derived from esophageal cancer, seemed to be of true endocrine cell origin, while the 3 other small-cell gastrointestinal carcinoma lines seemed to arise via neoplastic neometaplasia from adenocarcinoma cells to endocrine cells.

Effects of sustained release formulation of thyrotropin-releasing hormone on learning impairments caused by scopolamine and AF64A in rodents

The effects of a sustained-release formulation of thyrotropin-releasing hormone (TRH-SR) on learning impairments induced by scopolamine and a cholinergic neurotoxin, ethylcholine aziridinium ion (AF64A), were examined in rodents. Subcutaneous injection of TRH-SR (2.8 mg/kg as free TRH) produced a sustained increase in immunoreactive plasma TRH levels up to about 2 weeks after dosing in rats. TRH-SR (0.56 and 2.8 mg/kg) given subcutaneously 7 days before the acquisition trial markedly ameliorated scopolamine-induced amnesia in mice, as evaluated with a passive avoidance task. Repeated administration of TRH for 7 days at doses of 0.2-5 mg/kg s.c. elicited a dose-dependent recovery from amnesia induced by scopolamine, whereas only the group treated with 5 mg/kg/day showed a significant improvement. The rats with bilateral intracerebroventricular injection of AF64A (3.75 nmol/brain) showed a significant impairment in the water maze task 2 weeks after surgery. TRH-SR (0.56 and 2.8 mg/kg) also exhibited a dose-dependent ameliorating action on the deficit. These findings indicate that TRH-SR ameliorates learning impairments produced by scopolamine and AF64A, and suggest that continuous infusion of TRH may have a potent learning and memory improving action at low doses.

[Treatment of aplastic anemia with antithymocyte globulin, Lymphoser Berna]

Twenty-four patients with aplastic anemia (19 severe: 5 moderate) were treated with combined immunosuppression consisting of antithymocyte globulin (ATG: Lymphoser Berna, Swiss Serum and Vaccine Institute Berne) and high-dose methylprednisolone. Danazol or meptiostane was administered concurrently for at least 3 months. Three batches of ATG were used, two were not absorbed with thrombocytes and one was absorbed with thrombocytes for the prevention of thrombocytopenia. Nine of 20 evaluable patient (45%) had sustained improvement in hematopoiesis within 3 months of treatment. Nine of 14 patients (64%) showed a response to ATG without thrombocyte absorption, on the other hand, none of 6 patients responded to ATG with thrombocyte absorption. By life table analysis, the 3 year probability of survival was 81 +/- 27% after the combined immunosuppressive therapy. These results indicated that ATG therapy was very effective in Japanese patients with aplastic anemia.

The disposition and renal handling of enprofylline in endotoxemic rats by bacterial lipopolysaccharide (LPS)

The effects of lipopolysaccharide (LPS), isolated from Klebsiella pneumoniae (O3:K1-), on the pharmacokinetic behavior and renal handling of enprofylline, which is mainly excreted into the urine by an active tubular secretion mechanism, were investigated in rats. LPS (50 and 250 micrograms/kg) was infused for 20 to 30 min 2 hr before an intravenous administration of enprofylline (2.5 mg/kg). LPS induced a decrease in the systemic clearance and an increase in the volume of distribution at the steady state of enprofylline without any histological changes in the kidneys. No changes in the protein-binding parameters of enprofylline were observed between the control and LPS-pretreated groups, although LPS slightly decreased the albumin concentration in plasma. LPS caused decreases in the apparent maximum capacity of transport (Vmax) from 71.24 to 15.02 micrograms/min, in the Michaelis-Menten constant (KM) from 3.04 to 1.42 micrograms/ml, and in the glomerular filtration rate as estimated for inulin clearance from 3.10 to 1.87 ml/min. These results indicate that LPS decreases both the affinity and capacity of the tubular transport system, and in turn decreases the tubular secretory intrinsic clearance of enprofylline as shown by Vmax/KM. The mechanism for inducing changes in the pharmacokinetic behavior and renal handling of enprofylline by LPS may be related to the effects of LPS on tubular secretion of enprofylline and its distribution in the organs and peripheral tissues.

Expression of interleukin 6 and major histocompatibility complex molecules in tubular epithelial cells of diseased human kidneys

BACKGROUND

Interleukin-6 (IL-6) exerts multiple effects on infiltrated inflammatory cells and on structural cells in tissues. We previously reported that IL-6 expression is increased in the area of glomerular and tubular inflammation and tubular atrophy (Lab Invest 65:61, 1991). In the present study, we investigated the expression of IL-6 and HLA molecules in the tubules of patients with renal diseases, and correlate it with the morphological findings.

EXPERIMENTAL DESIGN

Specific monoclonal antibodies and indirect immunofluorescence microscopy were used to identify IL-6, HLA-ABC, and -DR molecules, CD-2+ and CD-8+ lymphocytes and macrophages, in renal tissues obtained by biopsy from 41 patients that were divided into three groups on the basis of clinical, functional, and histologic findings. Group 1 included 12 patients with signs of acute renal disease and prevalent acute tubulointerstitial lesions. Group 2 included 19 patients with signs of chronic renal disease and histologic lesions of glomerulo- and tubulointerstitial nephritis. Group 3 included 10 patients that developed an acute renal disease treated with corticosteroids. When the acute symptoms subsided and the renal biopsy was performed, lesions characteristic of chronic tubulointerstitial nephritis were found.

RESULTS

IL-6 was localized in all or in some cells of injured proximal tubules, including atrophic tubules. In one-third of specimens, there was more IL-6 in tubular cells than in infiltrated cells. The strongest expression of IL-6, HLA-ABC, and DR molecules was found in group 1, and the weakest in group 3. In the area with tubulointerstitial lesions, tubular IL-6 colocalized with HLA-ABC. Colocalization of IL-6 and HLA-DR was more evident in tubulointerstitial lesions of patients in group 2. In both groups 1 and 2, the distribution of IL-6 was statistically correlated with that of HLA-ABC and with interstitial infiltration of inflammatory cells. In group 2, there was statistical correlation between the expression of IL-6 and HLA-DR. The expression of IL-6 and of HLA molecules decreased in group 3.

CONCLUSIONS

These results suggest that tubular IL-6 may be involved in the pathogenesis of tubulointerstitial nephritis.

Purification and characterization of flavine-adenine dinucleotide phosphohydrolase from rat liver lysosomal membranes

An enzyme hydrolyzing flavine-adenine dinucleotide (FAD) to flavine mononucleotide (FMN) and adenosine monophosphate (AMP) was purified about 460-fold over the isolated lysosomal membranes with 9% recovery to apparent homogeneity, as determined from the pattern on polyacrylamide gel electrophoresis in the presence and the absence of SDS. Purification procedures included: preparation of crude lysosomal membranes, solubilization with Triton X-100, WGA-Sepharose, Con A-Sepharose, hydroxylapatite chromatography, gel filtration with Superdex 200, DEAE ion exchange chromatography, and preparative polyacrylamide gel electrophoresis. The molecular mass of the purified enzyme, estimated by gel filtration with Superdex 200, was approximately 560 kDa, and SDS-polyacrylamide gel electrophoresis showed the enzyme to be composed of four identical subunits with an apparent molecular weight of 140,000. The pH optimum for FAD hydrolysis was 8.5 with an apparent Km of 0.1 mM and the isoelectric point was pH 7.3. The activity was inhibited by o-phenanthroline, EDTA, DTT, and NEM and was slightly stimulated by Zn ion, but was not affected by Ca or Mg ions. The purified FADase contained N-linked complex type oligosaccharide chains lacking neuraminic acids. The NH2 terminal 21 amino acid residues of the purified FADase were Ser-Pro-Cys-Val-Cys-Asp-Pro-Val-Val-Val-Cys-Lys-Val-Val-Pro-Cys-Thr-Leu- Ala-Leu .

[Corneal curvature of myopia]

We classified myopia by total refractive error, measured the corneal curvature, and analyzed the relationship between the diopter value and corneal curvature in growing teen-agers and in adults in their twenties, whose myopic progress is presumed to have stopped. We adopted as the harmonic average the central 3.0 mm of the cornea. We also examined peripheral corneal curvature in upper side, lower side, temporal side and nasal side at about 4.5 mm and 6.5 mm diameter from the center. There was very little difference in the harmonic average of corneal curvature from -1D to -6D. Similarly, there was very little difference in the peripheral corneal curvature. The corneal curvature was larger from central to periphery in all directions. The upper side was larger than lower side and the nasal side was larger than the temporal side. We concluded that the refractive power did not depend on the corneal refractive power in mild to moderate myopic patients.

Haemodynamic and clinical effects of an intravenous potassium channel opener--a review

Intravenous nicorandil (4-12 mg) produced a significant decrease in mean arterial blood pressure (-5 to -15%), systemic vascular resistance (-8 to -27%), pulmonary capillary wedge pressure (-15 to -41%) and left ventricular end-diastolic pressure (-8 to -18%) in patients with coronary artery disease, myocardial infarction or congestive heart failure. Cardiac output was significantly increased (+3 to +19%) in most studies. These haemodynamic effects of intravenous nicorandil (4-8 mg) were comparable to those of nitroglycerin (0.3 mg), although a greater decrease in preload was produced by nitroglycerin. Moreover, no significant haemodynamic tolerance developed over a 12 to 24 h period during continuous infusion of nicorandil (2.4 micrograms.kg-.min-1) in patients with heart failure, in contrast to nitroglycerin infusion (0.65 microgram.kg-1 x min-1). Intravenous nicorandil (4-12 mg) was also shown to produce a slightly smaller increase (8-27%) in the diameter of the large coronary arteries compared to that of sublingual nitroglycerin (0.3 mg) (16-32%) and to cause a significant decrease in coronary vascular resistance (-9 to -53%) and a significant increase in coronary sinus flow (+6 to +81%) in patients with coronary artery disease. The efficacy of intravenous nicorandil (2-6 mg.h-1) in unstable angina pectoris has been compared with that of isosorbide dinitrate (2-5 mg.h-1) in a double-blind, multicentre trial. Over a 3 to 9 day period, nicorandil therapy tended to be more effective in abolishing anginal attacks and decreasing nitroglycerin consumption.

Purification of motility factor (GMF) from human malignant glioma cells and its biological significance in tumor invasion

Two molecular species of glioma-derived motility factor (GMF), GMF-I and GMF-II, have been purified to homogeneity from the serum-free conditioned medium of a highly invasive human glioma cell line, T98G, by gelatin affinity chromatography and heparin affinity-, DEAE-, hydroxyapatite-, gel permeation- and sulfopropyl high performance liquid chromatography. GMF-I and GMF-II showed a single protein band on non-reducing SDS-polyacrylamide gel electrophoresis with a molecular mass of 145 kDa and 165 kDa, respectively. The physico-chemical characteristics of these two GMFs are similar with respect to amino acid composition. GMF-I and GMF-II both stimulated the migration of T98G cells in a concentration-dependent manner, and the activity of GMF-I was about 5 times as strong as that of GMF-II. Checkerboard analysis demonstrated that the GMFs had not only a chemotactic effect but also a chemokinetic effect on T98G cells. C6 glioma cells and T98G cells, both of which showed high invasiveness in an in vitro invasion assay with reconstituted basement membrane, Matrigel, migrated to the GMFs with great intensity, while A172 and 9L glioma cells and normal glial cells, all of which weakly infiltrated the Matrigel barrier, migrated to the GMFs with much less intensity. These results indicate that migratory response of glioma cells to the GMFs correlates well with invasiveness, suggesting an important role(s) of the GMFs in the process of glioma cell invasion.

An acceleration of age-related increases in levels of the beta-subunit of nerve growth factor in selected tissues from senescence-accelerated mice (SAM-P/8)

An investigation was made of age-related changes in levels of the beta-subunit of nerve growth factor (beta-NGF) in selected tissues and of testosterone in serum in senescence-accelerated mice (SAM-P/8) and in the control mice (senesence-resistant mice; SAM-R/1). The concentrations of testosterone in serum were higher in SAM-P/8 than in SAM-R/1 at ages 2 and 4 mo. The level of beta-NGF in the thymus from SAM-R/1 increased with age, resulting in a statistically significant difference in its level between mice at ages 2 and 12 mo. By contrast, there was a transient increase in SAM-P/8 at around age 4 mo with a subsequent decrease. Consequently, significant differences were apparent in levels of beta-NGF between the two types of mouse at ages 2 and 4 mo. Similar results were obtained in the adrenal gland and testis. Compared to SAM-R/1 at age 2 mo, the average concentrations of beta-NGF in the hypophysis were higher in SAM-R/1 at ages 4 and 8 mo and in SAM-P/8 at all ages. In other tissues tested, no remarkable differences were detected. Our present results indicate that, in SAM-P/8, the elevation in levels of beta-NGF in the thymus, adrenal gland, testis, and hypophysis occurs in the early period of life compared to the control mice. Possible dysfunction of the disorder of hypophysis is discussed.

Increased levels of calbindin-D in serum and urine from patients treated by extracorporeal shock wave lithotripsy

Calbindin-D 28 kDa. is a vitamin D-dependent calcium binding protein that is found mainly in the distal renal tubules and central nervous tissue in humans. Calbindin-D was measured in the serum and urine before, and immediately, 2 hours or 24 hours after extracorporeal shock wave lithotripsy (ESWL*) in 83 consecutive patients. ESWL was performed with the Siemens Lithostar device in 61 patients and with the Dornier MPL9000 lithotriptor in 22. The serum 28 kDa. calbindin-D level was undetectable (less than 20 pg./ml.) in many samples, whereas urinary 28 kDa. calbindin-D could be detected in every sample. The serum 28 kDa. calbindin-D level was usually elevated after ESWL and the concentration in patients treated with the MPL9000 device was greater than in those treated with the Lithostar instrument. Urinary 28 kDa. calbindin-D levels were elevated significantly immediately and at 2 hours after ESWL, and they decreased to the baseline level within 24 hours after ESWL in the Lithostar group but remained consistently significantly elevated after ESWL in the MPL9000 group. This fact may be because the MPL9000 lithotriptor produces a stronger shock wave than does the Lithostar device during ESWL. These results suggest that 28 kDa. calbindin-D is released from damaged distal renal tubule cells into the serum and urine during ESWL and that 28 kDa. calbindin-D is a specific marker for renal damage by ESWL. To our knowledge this is the first clinical study using a sensitive enzyme immunoassay for human 28 kDa. calbindin-D to estimate renal damage during ESWL.

[Detection of myocardial ischemia by 99mTc-Teboroxime myocardial SPECT: a comparison with 201Tl myocardial SPECT]

Exercise myocardial SPECT using 99mTc-Teboroxime was performed and the regions of ischemic area were compared with 201Tl myocardial SPECT in 8 patients with coronary artery disease. All patients had no evidence of previous myocardial infarction, and underwent bicycle ergometer exercise according to a standardized multistage exercise protocol. At peak exercise, 555 MBq 99mTc-Teboroxime or 75 MBq 201Tl was injected intravenously. After termination of exercise, images were obtained with a gamma camera rotating through a 180 degrees arc from 45 degrees right anterior oblique to 45 degrees left posterior oblique. The concordance of 99mTc-Teboroxime SPECT and 201Tl SPECT was 63% in ischemic region and 83% in normal region. Furthermore, one patient underwent dipyridamole infusion and 99mTc-Teboroxime SPECT was carried out. The images obtained by dipyridamole 99mTc-Teboroxime SPECT were equivalent to the images of exercise 201Tl SPECT. 99mTc-Teboroxime SPECT seems useful for the detection of the coronary artery disease. It was suggested that evaluation of the myocardial viability in acute phase of myocardial infarction can be possible by using 99mTc-Teboroxime SPECT.

Putative, selective inhibitors of sarcoplasmic reticulum Ca+(+)-pump ATPase inhibit relaxation by nitroglycerin and atrial natriuretic factor of the rabbit aorta contracted by phenylephrine

Using three putative, selective inhibitors of the Ca+(+)-pump ATPase of sarcoplasmic reticulum (SR), cyclopiazonic acid, thapsigargin and 2,5-di-(tert-butyl)-1,4-benzohydroquinone, the mechanisms of relaxation of the arterial smooth muscle by cyclic GMP-generating vasodilators were studied in the ring preparations of the rabbit aorta. Nitroglycerin (NTG) and atrial natriuretic factor (ANF) were used as representative cyclic GMP-generating vasodilators. When the above three inhibitors of SR Ca+(+)-pump ATPase were present during the period of reloading of intracellular store sites with Ca++, the phasic contractions induced by phenylephrine or caffeine in the succeeding period in Ca+(+)-free media containing 2 mM EGTA were inhibited in a concentration-dependent manner. With 3 x 10(-5) M of cyclopiazonic acid the inhibition was almost complete for both agonists. NTG and ANF relaxed the aorta contracted by phenylephrine (10(-6) M) and produced an increase in cyclic GMP content. All the three SR Ca+(+)-pump ATPase inhibitors produced a concentration-dependent inhibition of the relaxation by NTG and ANF without affecting the increment of cyclic GMP content. These results indicate that the proper functioning of SR Ca+(+)-pump ATPase is necessary for elicitation of relaxation by NTG and ANF. Enhanced sequestration of Ca++ by SR may be an important mechanism by which these compounds induce relaxation in this type of smooth muscle.

Identification of the T cell surface signal-transducing glycoprotein sgp-60 as CD48, a counter-receptor for mouse CD2

We recently showed that CD48 is the major counter-receptor for CD2 in the murine system. To examine whether sgp-60, which has been proposed as the murine homologue of human LFA-3, is another ligand for mouse CD2, we performed the characterization of sgp-60 by using mouse CD2-human IgG chimeric protein (mCD2Rg) and anti-mouse monoclonal antibodies (mAb). Anti-sgp-60 mAb 5-8A10, as well as anti-mouse CD48 mAb HM48-1 completely inhibited the binding of mCD2Rg at the ligand site. 5-8A10 immunoprecipitated the same molecule as that recognized by HM48-1 and reacted with mouse CD48 cDNA-transfected chinese hamster ovary cells, indicating that sgp-60, recognized by 5-8A10, is identical to mouse CD48. The epitope recognized by 5-8A10 was different from that recognized by HM48-1 and OX78, suggesting that the different T cell activating property of these anti-mouse CD48 mAb depends on the epitopes they recognize. The identification of sgp-60 as CD48 further suggests a role of CD48 in regulating T cell activation.

[Cotard's syndrome in chronic schizophrenia]

A middle-aged woman who developed Cotard's syndrome after suffering from chronic schizophrenia is described. She had the delusion of negation believing that she had no possessions, but also her lung, heart, and intestines were gone. She also considered herself immortal. Medication was not useful in removing her delusions of negation and immortality.

Immunohistochemical localization of cathepsins B, D and L in the rat osteoclast

Immunohistochemical localization of cathepsins B, D and L in the osteoclasts of rat alveolar and femoral bones was investigated by using the avidin-biotin-peroxidase complex method for semithin, 1-micron-thick cryosections. Extracellular immunoreactivity for cathepsins B and L was clearly demonstrated along the bone resorption lacunae; the intensity of the extracellular immunoreactivity of cathepsin L was stronger than that of cathepsin B. However, the intracellular immunoreactivity of both cathepsins was weak compared with that of cathepsin D. The intracellular immunoreactivity of cathepsin D in the osteoclasts was clearly observed in the granules and/or vacuoles, but extracellular cathepsin D immunoreactivity was either negligible or not detected along the resorption lacunae. In the adjacent sections stained with anti-cathepsin L or D, extensive extracellular deposition of cathepsin L was found along the bone resorption lacunae, with or without osteoclasts, although the intracellular reactivity of cathepsin L was weak. This is the first morphological study in which cathepsins B and L have been demonstrated to be produced in the osteoclasts and extensively secreted into resorption lacunae, and in which cathepsin D was found to be present in the cells but scantily secreted into the lacunae. These findings suggest that cathepsins B and L directly and effectively participate in the degradation of the bone matrix.

A soluble multimeric recombinant CD2 protein identifies CD48 as a low affinity ligand for human CD2: divergence of CD2 ligands during the evolution of humans and mice

To search for possible ligands of CD2 distinct from CD58 (lymphocyte function-associated antigen 3), we have produced a soluble pentameric CD2-immunoglobulin (Ig) fusion protein (spCD2) linking the 182-amino acid human CD2 extracellular segment with CH2-CH3-CH4 domains of human IgM heavy chain, thus enhancing the micromolar affinity of the CD2 monomer through multimeric interaction. Using quantitative immunofluorescence and standard stringency wash conditions, we observed that the binding of spCD2 to human B lymphoblastoid JY cells and red blood cells is virtually inhibited by anti-CD58 TS2/9 monoclonal antibody, even though these cells express levels of CD48 and CD59 comparable to CD58. Consistent with these results, spCD2 did not show any binding to Chinese hamster ovary (CHO) cells transfected with human CD48 or CD59. However, binding studies on CD48-, CD58-, or CD59-transfected CHO cells with spCD2 under low stringency wash conditions revealed that human CD48 is a low affinity ligand of human CD2 compared with CD58 (Kd approximately 10(-4) vs. approximately 10(-6) M, respectively). The findings are noteworthy given that in the murine system CD48 is the major ligand for CD2. No detectable binding was observed to CD59-transfected CHO cells despite a report suggesting that CD59 may bind to the human CD2 adhesion domain. Importantly, in cell-cell adhesion assays between CD2+ Jurkat T cells and CD48- or CD59-transfected CHO cells, there was no conjugate formation, whereas binding of Jurkat T cells to CD58-transfected CHO cells was readily detected. Collectively, our findings provide evidence for a conservation of the CD2-CD48 interaction in the human species that may be of limited, if any, functional significance. Given the importance of the CD2-CD48 interaction in the murine system and CD2-CD58 interaction in humans, it would appear that there has been a divergence of functional CD2 ligands during the evolution of humans and mice.

Relationship between myoglobin contents and increases in cyclic GMP produced by glyceryl trinitrate and nitric oxide in rabbit aorta, right atrium and papillary muscle

Effects of glyceryl trinitrate (GTN) and nitric oxide (NO) on the cardiac functions and myocardial cyclic GMP (cGMP) contents were examined in comparison with those in the aorta and correlated with myoglobin (an inhibitor of soluble guanylate cyclase) contents using the preparations isolated from the reserpinized rabbit. GTN (10(-10)-10(-4) mol/l) produced a dose-dependent relaxation in the aorta. However, this compound exerted no effect on the rate of the spontaneous beat of the right atrium and the contraction of the papillary muscle. A transient and significant increase in cGMP was observed in the aorta with GTN (3 x 10(-6) mol/l). Although the increase was also observed in the right atrium, it was much smaller. No definite change was observed in papillary muscle. Increases in cGMP produced by NO (3 x 10(-6) mol/l) were larger and significant in all tissues; (AUCcGMP(GTN)/AUCcGMP(NO)) ratio was 30.1 for the aorta, 65.0 for the right atrium and 16.3% for the papillary muscle. Although higher concentrations of NO were necessary in the right atrium and papillary muscle to induce increases in cGMP, no differences were noted in the three tissues as regards the maximum accumulation of this substance. Furthermore, kinetic analysis of NO-induced increases in tissue cGMP indicated no marked difference in the production rate among the three tissues, while the rate of elimination of cGMP was lower in the aorta than in the atrium or the papillary muscle. The increases in cGMP observed in these three tissues were inversely related to the contents of myoglobin in respective tissues.(ABSTRACT TRUNCATED AT 250 WORDS)

Antigenic properties of Campylobacter rectus (Wolinella recta) major S-layer proteins

The antigenic properties of the surface layer (S-layer) proteins of various Campylobacter rectus strains including 24 clinical isolates and the type strain ATCC 33238 were examined. S-layer proteins were extracted from whole cells by acid treatment according to the method of McCoy et al. (Infect. Immun. 11, 517-525, 1975). The acid extracts from 23 of the isolates and ATCC 33238 contained two major proteins with molecular masses of 130 kDa and 150 kDa, both of which were identified as subunits of the S-layer after comparison with the protein profiles of acid-treated (S-layer-deficient) cells. An S-layer protein from one isolate (CI-808) demonstrated a different molecular mass (160 kDa). Both the 150-kDa proteins of ATCC 33238 and isolate CI-306 and the 160-kDa protein of CI-808 were purified by ion-exchange chromatography in the presence of urea. In Ouchterlony immunodiffusion experiments with these purified proteins and rabbit antiserum raised to each purified protein, both common and strain-specific antigenic determinants were identified in the C. rectus S-layer proteins.

Cross-linking of lipopolysaccharide (LPS) to CD14 on THP-1 cells mediated by LPS-binding protein

Recent work has established that bacterial endotoxin (LPS) binds to the plasma protein LPS-binding protein (LBP) forming high affinity complexes (LPS-LBP), that LBP is an opsonin for LPS-bearing particles, and that LPS-LBP complexes are potent agonists for monocytic cells (MO). mAb to the MO plasma membrane protein, CD14, inhibit LBP-dependent binding of LPS to MO, and LPS-LBP-dependent stimulation of cytokine release from MO. These data suggest that CD14 functions as a membrane receptor for LPS but do not demonstrate a direct association of LPS with CD14. Calcitriol was used to induce a high level of CD14 expression in the human monocyte-like cell line THP-1, resulting in enhanced responses of these cells to LPS-LBP complexes manifested by enhanced binding of LPS and a decrease in the amount of LPS needed to induce IL-8 release. An Re595 LPS derivative containing a radioiodinated, photoreactive, phenyl azide (125I-ASD-LPS) was used in cross-linking experiments to identify membrane proteins in calcitriol-treated THP-1 cells that interact with LPS. 125I-ASD-LPS was added to calcitriol-induced THP-1 cells in the presence or absence of LBP, the mixture photolyzed, and the resultant radioiodinated proteins analyzed by SDS-PAGE and autoradiography. We observed strong cross-linking of 125I-ASD-LPS to a 55-kDa membrane protein when LBP was present, but failed to observe radiolabeling of any other proteins with apparent molecular masses distinct from CD14. The cross-linked product was identified as CD14 by immunoprecipitation with anti-human CD14 mAb. Studies with human CD14 expressing transfectants of the murine B cell line 70Z/3 also revealed LBP-dependent cross-linking of 125I-ASD-LPS to CD14. These data document binding of LPS to a specific membrane protein that serves as an LPS receptor.