Identification of chondromodulin I as a novel endothelial cell growth inhibitor. Purification and its localization in the avascular zone of epiphyseal cartilage

Cartilage is unique among tissues of mesenchymal origin in that it is resistant to vascular invasion due to an intrinsic angiogenic inhibitor. During endochondral bone formation, however, calcified cartilage formed in the center of the cartilaginous bone rudiment allows vascular invasion, which initiates the replacement of cartilage by bone. The transition of cartilage from the angioresistant to the angiogenic status thus plays a key role in bone formation. However, the molecular basis of this phenotypic transition of cartilage has been obscure. We report here purification of an endothelial cell growth inhibitor from a guanidine extract of bovine epiphyseal cartilage. The N-terminal amino acid sequence indicated that the inhibitor was identical to chondromodulin I (ChM-I), a cartilage-specific growth-modulating factor. Purified ChM-I inhibited DNA synthesis and proliferation of vascular endothelial cells as well as tube morphogenesis in vitro. Expression of ChM-I cDNA in COS7 cells indicated that mature ChM-I molecules were secreted from the cells after post-translational modifications and cleavage from the transmembrane precursor at the predicted processing signal. Recombinant ChM-I stimulated DNA synthesis and proteoglycan synthesis of cultured growth plate chondrocytes, but inhibited tube morphogenesis of endothelial cells. In situ hybridization and immunohistochemical studies indicated that ChM-I is specifically expressed in the avascular zone of cartilage in developing bone, but not present in calcifying cartilage. These results suggest a regulatory role of ChM-I in vascular invasion during endochondral bone formation.

Identification of an autocrine chondrocyte colony-stimulating factor: chondromodulin-I stimulates the colony formation of growth plate chondrocytes in agarose culture

Chondrocytes are unique among non-transformed cells in that they are capable of anchorage-independent growth in soft agar. Fibroblast growth factor (FGF) is known as a potent colony-stimulating factor for chondrocytes. However, cartilage extracts contain a potent colony-stimulating activity which is not explicable only by contaminating FGF. We previously isolated the 25 kDa cartilage-specific glycoprotein chondromodulin-I (ChM-I) which stimulates the growth of chondrocytes. In the present study, we observed that ChM-I stimulates the colony formation of rabbit growth plate chondrocytes in agarose culture. ChM-I alone weakly stimulated the formation of chondrocyte colonies, but it markedly stimulated colony formation synergistically in the presence of an optimal dose of FGF-2. This effect was dependent on the dose of ChM-I. These results suggest that ChM-I participates in an autocrine signaling mechanism for the anchorage-independent growth of chondrocytes in vitro.

Purification and cloning of hepatocyte growth factor activator inhibitor type 2, a Kunitz-type serine protease inhibitor

Hepatocyte growth factor (HGF) activator is a serine protease responsible for proteolytic activation of HGF in response to tissue injury and thus plays an important role in the regulation of biological functions of HGF in regenerating tissue. We previously purified an inhibitor of HGF activator (HGF activator inhibitor type 1, HAI-1) from the conditioned medium of a human stomach carcinoma cell line MKN45 and cloned its cDNA. HAI-1 is a novel member of the Kunitz family of serine protease inhibitors. In the present study, we purified a second type of HGF activator inhibitor (HAI-2) from the conditioned medium of MKN45 cells and molecularly cloned its cDNA. The cDNA sequence revealed that HAI-2 is derived from a precursor protein of 252 amino acids and contains two Kunitz domains, indicating that HAI-2 is also a member of the Kunitz family of serine protease inhibitors. The primary translation product of HAI-2 has a hydrophobic sequence in the COOH-terminal region, suggesting that, like HAI-1, HAI-2 is produced in a membrane-associated form and secreted in a proteolytically truncated form. Because HAI-2 and HAI-1 are potent inhibitors specific for HGF activator, they may be involved in regulation of proteolytic activation of HGF in injured tissues.

Inhibition of DNA synthesis and tube morphogenesis of cultured vascular endothelial cells by chondromodulin-I

Cartilage is an avascular tissue, and exhibits anti-angiogenic properties. Cartilage extracts have been shown to contain an inhibitor for DNA synthesis in vascular endothelial cells in vitro. Here we purified the inhibitory activity in the 10-50 kDa fraction of guanidine extracts from fetal bovine epiphyseal cartilage, and found that the inhibitor was identical with chondromodulin-I (ChM-I). Purified ChM-I inhibited tube morphogenesis of cultured vascular endothelial cells, as well as DNA synthesis. These results indicate that cartilage-specific glycoprotein ChM-I may participate in the maintenance of avascularity and anti-angiogenic properties of cartilage.

Time dependent alterations of serum matrix metalloproteinase-1 and metalloproteinase-1 tissue inhibitor after successful reperfusion of acute myocardial infarction

OBJECTIVE

To test the hypothesis that changes in serum matrix metalloproteinase-1 (MMP-1) and tissue inhibitors of metalloproteinase-1 (TIMP-1) after acute myocardial infarction reflect extracellular matrix remodelling and the infarct healing process.

PATIENTS

13 consecutive patients with their first acute myocardial infarction who underwent successful reperfusion.

METHODS

Blood was sampled on the day of admission, and on days 2, 3, 4, 5, 7, 14, and 28. Serum MMP-1 and TIMP-1 were measured by one step sandwich enzyme immunoassay. Left ventricular volume indices were determined by left ventriculography performed four weeks after the infarct.

RESULTS

Serum concentrations of both MMP-1 and TIMP-1 changed over time. The average serum MMP-1 was more than 1 SD below the mean control values during the initial four days, increased thereafter, reaching a peak concentration around day 14, and then returned to the middle control range. Negative correlations with left ventricular end systolic volume index and positive correlations with left ventricular ejection fraction were obtained for serum MMP-1 on day 5, when it began to rise, and for the magnitude of rise in MMP-1 on day 5 compared to admission. Serum TIMP-1 at admission was more than 1 SD below the mean control value, and increased gradually thereafter, reaching a peak on around day 14. Negative correlations with left ventricular end systolic volume index and positive correlations with left ventricular ejection fraction were obtained for serum TIMP-1 on days 5 and 7, and for the magnitude of rise in TIMP-1 on days 5 and 7 compared to admission.

CONCLUSIONS

Both MMP-1 and TIMP-1 showed significant time dependent alteration after acute myocardial infarction. Thus MMP-1 and TIMP-1 may provide useful information in evaluating the healing process as it affects left ventricular remodelling after acute myocardial infarction.

Plasma interleukin-6 is not a mediator of changes in lipoprotein lipase activity in cancer patients

BACKGROUND/AIMS

Cancer cachexia is characterized by a variety of metabolic disorders. Alterations in fat metabolism have been reported to be associated with suppression of tissue lipoprotein lipase (LPL) activity in tumor-bearing animals. Interleukin-6 (IL- 6) has been documented to reduce tissue LPL activity and may play a role in inducing cancer cachexia. This study was conducted to clarify the changes in LPL activity and the role of IL-6 in patients with either gastrointestinal cancer or breast cancer.

METHODOLOGY

Twelve patients with colorectal cancer, 7 patients with gastric cancer, 7 patients with breast cancer and 5 normal volunteers were studied. Serum concentrations of triglycerides (TG), non-esterified fatty acids (NEFA) and IL-6 were measured. LPL activity was measured in plasma post-heparin administration. The relationships of LPL activity to tumor progression, body weight loss and serum IL-6 levels were examined. The effect of tumor resection on LPL activity was also studied.

RESULTS

LPL activity was suppressed with tumor progression in patients with either gastrointestinal cancer or breast cancer. Suppression of LPL activity and the degree of weight loss were negatively correlated in patients with either gastric or colorectal cancer (r = -0.5826, p = 0.011) but not in patients with breast cancer. The decrease in LPL activity was not always reversed after resection of the tumor. Circulating IL-6 did not correlate with either plasma LPL activity or tumor progression.

CONCLUSIONS

Reduced LPL activity in patients with advanced gastrointestinal or breast cancer may reflect changes in nutritional status. Serum IL-6 is less likely to be a mediator of these alterations.

Isolation and conformational analysis of fragment peptide corresponding to the heparin-binding site of hepatocyte growth factor

Hepatocyte growth factor (HGF) is a potent mitogen for hepatocytes. The mitogenic activity of HGF is mediated by its binding to a high-affinity receptor, c-Met. Heparan sulfate is an initial binding site for HGF, based on its relative abundance on the cell surface. The binding of HGF to heparin or heparin-like molecules may induce oligomerization of HGF and facilitate c-Met-dependent mitogenesis [Zioncheck et al. (1995) J. Biol.Chem. 270, 16871-16878]. Thus, heparin binding is important for the biological activity of HGF. To identify the heparin-binding site of HGF, we isolated fragment peptides corresponding to the site by limited proteolysis and chemical degradation of recombinant human HGF (rhHGF). The heparin-binding ability of the peptides was expressed as their elution positions on heparin-affinity column chromatography with NaCl gradient elution. Because all of the heparin-binding peptides obtained in this study were isolated from the N-terminal hairpin-loop region (PyrGlu32-Asn127) of HGF, the region was identified as the heparin-binding site of HGF. One of the isolated peptides, Phe42-Glu111, containing the N-terminal hairpin-loop structure, was considered a suitable model peptide for the heparin-binding site of HGF. From the observation using circular dichroism spectroscopy, it was indicated that the secondary structure of the peptide changed from a random structure to a beta-sheet-like structure upon heparin binding. In addition, oligomerization of HGF in the presence of heparin was observed by dynamic light scattering. Based on our evidence, it is considered that the conformational change in the heparin-binding site may induce the oligomerization of HGF.

Use of a bovine jugular vein graft with natural valve for right ventricular outflow tract reconstruction: a one-year animal study

OBJECTIVE

We evaluated a bovine jugular vein graft with a natural trileaflet valve for right ventricular outflow tract reconstruction in a canine study for an entire year.

METHODS

Heparinized bovine jugular vein grafts with a natural valve cross-linked with a hydrophilic polyepoxy compound of 18 to 20 mm in internal diameter were implanted in the right ventricular-pulmonary arterial position in eight dogs, and the main natural pulmonary artery was ligated. Anticoagulants were not used after implantation. Five grafts were retrieved on day 182 after implantation and the other three grafts on days 196, 375, and 385, respectively, and were inspected by macroscopic and microscopic observation. Cardiac catheterization, followed by angiography and echocardiography, was done just before graft retrieval.

RESULTS

No graft kinking or regurgitation of the valve was observed. Echocardiography showed natural valve motion without thickening of the leaflets. Blood pressure in the conduits ranged from 18/9 to 31/4 mm Hg, in the right ventricle from 18/4 to 40/0 mm Hg, and the gradient varied from 0 to 14 mm Hg. The explanted conduits maintained their original shape, softness, and pliability with good coaptation of valves, without calcification or degenerative changes, except for one leaflet with slight deformation. In microscopic observation, endothelial cells lined the luminal surface of the conduit except for the areas adjacent to the valve.

CONCLUSION

The graft worked perfectly as a right ventricular-pulmonary arterial valved conduit without anticoagulant therapy for a long time.

[Assessment of quality of life in long-term results of patients over 75 years old after emergent cardiovascular surgery]

Long-term results in QOL of patients over 75 years old after emergent cardiovascular surgery were examined. From January 1991 to June 1996, 46 patients underwent cardiovascular surgery. 22 patients who had elective surgery (elective group) and 15 patients who had emergency surgery (emergency group) tolerated with the operation: Two-year survival rate after surgery was 80.7% in the elective group and 78% in the emergency group, and relative survival rate was 0.89 in the elective group and 0.86 in the emergency group. As regards to the ability to live independently, 89% of elective group and 75% of emergency group showed good improvement, and there was no significant difference between two groups. The rate of patients who did not feel anxiety for disease at all was 61.1% in the elective group and 41.7% in the emergency group. The relationship between the patient and his family was good in both groups. For physical condition, the emergency group was superior to the elective group with no significant difference. Although QOL was relatively good after emergency surgery, some items were inferior compared with elective surgery. To improve the long-term results, elective surgery is required to avoid emergency surgery.

[Surgery for acute aortic dissection extending to the aortic root using gelatine-resorcine-formol biological glue--a case report]

A 73-year-old woman was admitted with chest pain of sudden onset and hypotension. Enhanced CT showed the dilated ascending aorta with an intimal flap. Emergency surgery was performed under a diagnosis of type A acute aortic dissection and cardiac tamponade. Replacement of the ascending aorta was planned, but during the operation we found that the dissection had extended to the aortic root and that the laceration of the adventitia was located just distal to the aortic annulus. Since the laceration was closer to the aortic annulus than the coronary ostium, it was impossible to reconstruct the aortic stump by classical techniques using Teflon felt strips. Gelatine-Resorcine-Formol (GRF) glue was therefore used to reinforce the proximal aortic stump. We then curved the suture line of the proximal anastomosis so as to resect the laceration while preserving the ostia of the coronary arteries. We were thus able to perform simple replacement of the ascending aorta successfully and the postoperative course was uneventful. By using GRF glue, replacement of the aortic root can be avoided in such cases.

Molecular cloning of cDNAs for mouse low-molecular-weight and high-molecular-weight prekininogens

We isolated cDNAs encoding low-molecular-weight (L-) and high-molecular-weight (H-) prekininogens from a mouse liver cDNA library using rat T-kininogen cDNA and rat H-kininogen cDNA respectively, as probes. The signal peptide, the heavy chain, and the bradykinin moiety, which are common between the two prekininogens, consist of 20, 359, and 9 amino acids, respectively, while the light chains of the L- and H-prekininogens are composed of 44 and 273 amino acids, respectively. All 19 cysteine residues present in both mouse prekininogens are located at the same positions relative to those of human origin. The light chain of H-prekininogen contains a characteristic 15-repeated His-Gly sequence and a conserved sequence for binding prekallikrein or factor XI. Northern blotting or reverse transcription-polymerase chain reaction followed by Southern blotting using mouse L- and H-kininogen cDNAs demonstrated that both L- and H-kininogens are predominantly expressed in the liver and kidney. L-Kininogen mRNA was also expressed in other tissues, such as the adrenal gland, brain, spinal cord, testis, lung, heart, and skin, while levels of H-kininogen mRNA in these tissues were too low to detect, suggesting that L-kininogen is synthesized in various tissues of mouse, while H-kininogen is exclusively synthesized in the liver and kidney. A genomic Southern blot using H-prekininogen cDNA revealed that the L- and H-prekininogen mRNAs in mouse are probably encoded by a single gene, as is the case in both human and bovine.

Hepatocyte growth factor activator inhibitor, a novel Kunitz-type serine protease inhibitor

Hepatocyte growth factor (HGF) activator is a serine protease that is produced and secreted by the liver and circulates in the blood as an inactive zymogen. In response to tissue injury, the HGF activator zymogen is converted to the active form by limited proteolysis. The activated HGF activator converts an inactive single chain precursor of HGF to a biologically active heterodimer in injured tissue. The activated HGF may be involved in the regeneration of the injured tissue. In this study, we purified an inhibitor of HGF activator from the conditioned medium of a human MKN45 stomach carcinoma cell line and molecularly cloned its cDNA. The sequence of the cDNA revealed that the inhibitor has two well defined Kunitz domains, suggesting that the inhibitor is a member of the Kunitz family of serine protease inhibitors. The sequence also showed that the primary translation product of the inhibitor has a hydrophobic sequence at the COOH-terminal region. Inhibitory activity toward HGF activator was detected in the membrane fraction as well as in the conditioned medium of MKN45 cells. These results suggest that the inhibitor may be produced as a membrane-associated form and secreted by the producing cells as a proteolytically truncated form.

Laminin alpha 1, alpha 2, alpha 4 and beta 1 chain mRNA expression in mouse embryonic, neonatal, and adult hearts

We examined the relative expression of laminin alpha 1, alpha 2, alpha 4 and beta 1 chain genes in the heart of embryonic, neonatal and adult BALb/c mice. The reverse transcriptase-polymerase chain reaction was employed to determine the mRNA expression of these chains because of the relatively small amount of RNA extracted from rat embryonic hearts. Glyceraldehyde 3-phosphate dehydrogenase and beta-actin were used as internal controls. Among the hearts examined, a relatively high expression of laminin alpha 1 chain was observed in the embryonic hearts, while its expression was very weak in the neonatal and negligible in the adult hearts. Conversely, expression of laminin alpha 2 chain was virtually not observed in the embryonic hearts, but this chain was expressed weakly in the neonatal and substantially in the adult hearts. Similar to laminin alpha 1, laminin alpha 4 was expressed in the embryonic hearts, while its expression was relatively weak in the neonatal and adult hearts. Laminin beta 1 was expressed in the hearts of mice at all stages examined. These results demonstrate that the laminin chain gene expression changes in the different developmental stages of the hearts of BALb/c mice.

Time-dependent increases in syndecan-1 and fibroglycan messenger RNA expression in the infarct zone after experimentally induced myocardial infarction in rats

BACKGROUND

Syndecan-1 and fibroglycan, heparan sulphate proteoglycans, play important roles in extracellular matrix formation via their biological functions.

OBJECTIVE

To examine experimentally the sequential changes in syndecan-1 and fibroglycan messenger RNA (mRNA) expression after acute myocardial infarction.

MATERIALS AND METHODS

The left coronary arteries of male Sprague-Dawley rats were ligated and the hearts were excised on days 1-14, 28 and 42. Syndecan-1 and fibroglycan mRNA expression in the infarct and non-infarct zones and in sham-operated hearts was determined by reverse transcriptase-polymerase chain reaction. Amplified products were quantified by densitometry of the electrophoresed bands stained with ethidium bromide and standardized relative to the glyceraldehyde 3-phosphate dehydrogenase or beta-actin mRNA expression. Northern hybridization was also performed in the infarct and non-infarct zones on day 3.

RESULTS

Expression both of syndecan-1 and of fibroglycan mRNA began to increase on day 2. The expression attained maximum levels on day 3. The maximum levels of syndecan-1 and fibroglycan expression were, respectively, sevenfold and fivefold the preligation level and the level in the sham-operated hearts. The levels remained elevated until day 14, whereupon they declined gradually, returning to the control levels by around day 42. Northern blotting also demonstrated that there was an increased expression both of syndecan-1 and of fibroglycan mRNA in the infarct compared with that in the non-infarct zone on day 3.

CONCLUSION

Our results demonstrated that there are sequential increases in the expression both of syndecan-1 and of fibroglycan mRNA in the infarct zone after experimentally induced myocardial infarction in rats, suggesting that these proteoglycans play some role in the pathological course of infarction.

Deep lamellar keratoplasty with complete removal of pathological stroma for vision improvement

AIMS/BACKGROUND

Deep lamellar keratoplasty (DLK) was performed to restore visual acuity in 120 eyes with corneal stromal opacification. DLK is believed to be an effective treatment in eyes in which endothelial cell function had been preserved, and in which there was no epithelial or stromal oedema. The purpose of this study was to evaluate the effectiveness of this treatment.

METHODS

The stroma was excised to the extent that only Descemet's membrane remained, at least in the optical zone. Donor corneas of full, or almost full, thickness with Descemet's membrane removed, or which had been lathed to a thickness of 0.4 mm from the endothelial side, were attached by suturing.

RESULTS

In 113 eyes which were observed for 6 months or more postoperatively in which average prospective visual acuity was 0.09, average postoperative visual acuity improved to 0.6. Specular microscopy 1 month postoperatively revealed average endothelial cell counts of 2225 (SD 659)/mm2, while 24 months postoperatively this value was 1937 (642)/mm2 (cell loss 13%). Puncturing of Descemet's membrane during surgery occurred in 47 of 120 eyes (39.2%), but after 12 months, there was no difference in visual acuity or number of endothelial cells between these eyes and those in which no puncturing had occurred.

CONCLUSIONS

There was no postoperative endothelial rejection reaction with DLK, and restoration of postoperative visual acuity was quite adequate. Compared with penetrating keratoplasty, DLK allows endothelial cell counts to be maintained for a longer period. In addition, results can be expected to be more consistent over the long term with DLK.

Low-affinity nerve growth factor receptor is associated with motoneuron axonal pathways

The unidentified cell-surface antigen recognized by monoclonal antibody M7412 is distributed along motoneuron axonal outgrowth pathways in chicken embryos. To better characterize its role in motoneuron development, the M7412 antigen was purified from chicken embryos by immunoaffinity chromatography. Its N-terminal amino acid sequence corresponded to that predicted for chicken low-affinity nerve growth factor receptor (LNGFR). Experiments were performed to confirm that LNGFR was indeed the antigen recognized by M7412. First, M7412 bound to recombinant chicken LNGFR expressed in mammalian cells. Second, a rabbit serum raised to the purified antigen showed the same staining pattern in chicken embryos as did M7412. Lastly, a novel method for direct detection of nerve growth factor (NGF) bound to its receptors was used to show that in mixed spinal cord cultures, only neurons that expressed M7412 antigen had low-affinity binding sites for NGF. Furthermore, at the subcellular level, M7412 labeling was co-localized with bound NGF. The M7412 antigen is thus chicken LNGFR, whose role in motoneuron outgrowth pathways is discussed.

A novel growth-promoting factor derived from fetal bovine cartilage, chondromodulin II. Purification and amino acid sequence

During endochondral bone formation, cartilage cells show increased matrix synthesis and rapid proliferation. We found that cartilage matrix contains at least two types of heparin binding growth-promoting components. One, with a higher affinity to heparin, was identified as chondromodulin I (Hiraki, Y., Tanaka, H., Inoue, H. , Kondo, J., Kamizono, A., and Suzuki, F. (1991) Biochem. Biophys. Res. Commun. 175, 871-977). In this study, we isolated a novel growth-promoting component, chondromodulin II, which has a lower heparin affinity, from the dissociative extracts of fetal bovine epiphyseal cartilage. Chondromodulin II stimulated the proteoglycan synthesis in rabbit cultured growth plate chondrocytes, an expression of the differentiated phenotype of chondrocytes. It also stimulated DNA synthesis in chondrocytes in both the absence and the presence of fibroblast growth factor-2. The apparent molecular mass of chondromodulin II on SDS-polyacrylamide gel electrophoresis was 16 kDa. Its complete amino acid sequence was determined by overlapping sequences of the peptides released by endopeptidase digestion and CNBr cleavage. Chondromodulin II consists of 133 amino acids (calculated Mr = 14,548). The sequence was unique but homologous to the repeats 1 and 2 of the deduced amino acid sequence of the chicken mim-1 gene, which is specifically transactivated by the v-Myb oncogene product in promyelocytes. We also found a minor component with a higher heparin affinity, chondromodulin III, in cartilage extracts. Chondromodulin III stimulated DNA synthesis in chondrocytes in vitro, and its N-terminal sequence was identical with ribosomal protein L31 lacking the N-terminal three amino acids. These findings suggest that the growth and differentiation of chondrocytes are regulated by multiple components in the cartilage matrix.

Expression of low-molecular-weight kininogen mRNA in human fibroblast WI38 cells

Expression of the low-molecular-weight kininogen (L-kininogen) mRNA in the human fibroblast cell line WI38 was examined by means of the reverse-transcription polymerase chain reaction and Southern blotting using human L-kininogen cDNA as a probe. The results demonstrated that WI38 fibroblasts expressed L-kininogen mRNA and that the expression was stimulated by 1 mM dibutyryl cAMP or 10 microM prostaglandin E2. Dexamethasone (1 microM) inhibited the stimulatory effect of prostaglandin E2. These results suggest that human fibroblasts supply L-kininogen, a protein precursor of the inflammatory mediator kinins, to connective tissues in response to inflammatory stimuli and that glucocorticoids may exert the antiinflammatory effect in part by inhibiting the local production of L-kininogen.

[Surgical treatment for active infective endocarditis : septic embolization and mycotic aneurysms]

From 1978 through 1995, surgical treatment for active infective endocarditis (native valve) was performed in 17 patients. The indication for operation at the active phase was progressive heart failure in 5 (A-group) and uncontrolled infection in 12 (B-group). Operative findings showed vegetations in all cases, perforations of the valve in 6, rupture of tendon in 2, and annular abscesses in 2. One patient in B-group died 14 days after the operation with postoperative mediastinitis and sepsis. There was no perioperative complications in A-group. In B-group before operations 8 patients (66.7%) has an embolic event before operations. The anatomic sites of embolization were the central nervous system (3 patients), viscera (2 patient) and peripheral arteries (3 patients). And after operation there were 2 mycotic aneurysms of the hepatic artery and the popliteal artery, and 1 pyogenic spondylitis. We conclude that the risk of embolization is high in patients undergoing surgery at active phase of infective endocarditis because of uncontrolled infection ; thus, such patients should be carefully monitored for emboli and mycotic aneurysms.

Extracellular matrix components in dilated cardiomyopathy. Immunohistochemical study of endomyocardial biopsy specimens

Fibrotic change is one of the characteristic features of the heart with idiopathic dilated cardiomyopathy (DCM), but the extracellular matrix components have not been fully clarified. Fibronectin, laminin, and types IV, I and III collagen staining using the avidin-biotin-peroxidase complex method was conducted to study the localization of extracellular matrix components in biopsy specimens obtained from 7 patients with DCM. Fibronectin was observed in the endomysium and perimysium, co-existent with types I and III collagen; it was also distributed nonhomogeneously in the replacement fibrotic lesions. The staining intensity in a section varied substantially from location to location. Laminin surrounded the myocytes and was distributed in the endomysium localized together with type IV collagen, but it was not found in the perimysium. Weak but positive staining was observed in replacement fibrotic lesions in 2 patients. Similarly to laminin, type IV collagen staining was observed around the myocytes and in the endomysium. It was also observed in replacement fibrotic lesions in 4 patients either with or without laminin. Type I collagen, localized together with type III collagen, was distributed in both the endomysium and perimysium. It was also distributed nonhomogeneously in the replacement fibrotic lesions. Similar staining to type I collagen was seen for type III collagen. In summary, all examined components were observed in the fibrotic lesions with no primary deficit of any examined component being demonstrated. The variability of staining intensity and positive fibronectin staining suggests that the phases of fibrotic changes differed substantially from location to location.

Relationship between response to interferon therapy and detection of hepatitis C virus RNA by differential flotation centrifugation

Circulating hepatitis C virus (HCV) particles can be fractionated by means of differential flotation centrifugation. It is reported that in the bottom fraction HCV is in the form immune complexes, whereas in the top, it is free of antibodies. We evaluated the significance of circulating complex and free HCV in chronic hepatitis C, and assessed the relationship in terms of the response to interferon (IFN) therapy. We examined sera before, just after, and 1 year after administering IFN to 18 patients with chronic hepatitis C, 10 of whom responded (group CR), and 8 did not (group NR). The amounts of virus were similar between both groups before therapy. After differential flotation centrifugation with 1.063 g/ml of NaCl, the top and bottom fractions were assayed for HCV RNA. Before therapy, HCV RNA was detected in the top fraction in 1 of 10 in group CR, and in 6 of 8 in group NR (P < 0.05, chi-square test). HCV RNA was positive in the bottom fraction of all samples. In a follow-up study of group NR, HCV RNA was detected in the top fraction in 3 of 8 just after IFN therapy, and in 7 of 8 after 1 year. This study suggests that the presence of HCV in the top fraction can predict a poor response to IFN therapy.

Fibroblasts synthesize kininogen in response to inflammatory mediators

Mouse fibroblasts in vitro secret kininogen (KGN). Rat fibroblasts also synthesized and secreted T-KGN in vitro. KGN production by these fibroblasts is greatly stimulated by dibutyryl cAMP, prostaglandin E2 and tumor necrosis factor. Human fibroblast WI-38 cells also express the L-KGN gene, which was stimulated by dibutyryl cAMP and prostaglandin E2. These results demonstrate that fibroblasts express the KGN gene, and suggest that the expression is regulated by inflammatory mediators. RT-PCR, using specific primers for the T-KGN and L-KGN genes, reveals that the rat hind-paw express both T- and L-KGN mRNAs, and the expression of both KGN mRNAs was increased in the hind-paw 24 h after inducing inflammation by injecting Freund's complete adjuvant into the paw. Thus, it is suggested that local connective tissues express the KGN gene, and that the expression is enhanced under pathological conditions, such as inflammation.

[Comparison between intermittent retrograde cold blood cardioplegia and retrograde crystalloid cardioplegia]

Intermittent retrograde cold blood cardioplegia was compared with retrograde crystalloid cardioplegia. Twenty-two adult patients underwent open heart surgery divided into two groups. Group BCP (n = 10) was protected with 15 degrees C blood containing potassium 15 mEq/l; Group CCP (n = 12) was protected with 4 degrees C St. Thomas' Hospital cardioplegic solution. Lactate, pyruvate, and CK-MB levels in coronary sinus blood were measured at 5 and 15 minutes after aortic unclamping and 5 minutes after weaning from cardiopulmonary bypass (CPB) in both groups. CPB time, cross-cross clamp time, incidence of postoperative low output syndrome and spontaneous return to sinus rhythm after aortic unclamping were not different between two groups. Cardiac index and pulmonary capillary wedge pressure measured immediately after weaning from CPB, were not different in both groups. Lactate level was significantly low in group BCP. Lactate uptaking ratio of myocardium was significantly high in group BCP. CK-MB levels were not different between two groups. Cold blood cardioplegia was seemed to provide better aerobic myocardial metabolism during aortic cross clamp. However, CK-MB levels and hemodynamic studies were not different.

Diagnostic significance of thrombin-antithrombin III complex (TAT) and D-dimer in patients with deep venous thrombosis

Thrombin-antithrombin III (TAT) and D-dimer were measured in 50 patients suspected of deep venous thrombosis (DVT) to assess the usefulness of these indicators in the diagnosis of DVT. DVT was diagnosed by ultrasonography (compression method and Doppler imaging). In patients who were negative for DVT (Group A), TAT was 3.8 +/- 2.36 micrograms/L (mean +/- SD) and D-dimer was 0.7 +/- 0.69 micrograms/ml, whereas in patients diagnosed with DVT (Group B), TAT was 20.4 +/- 19.10 micrograms/L (p < 0.001) and D-dimer was 9.0 +/- 9.21 micrograms/ml (p < 0.001). Thus, Group B had significantly higher levels of both markers. Moreover, 19 of the 23 cases in Group B had acute DVT, with symptoms appearing within 2 weeks of onset. When the cutoff for a positive diagnosis of DVT was set at TAT of 7.0 micrograms/L or more and D-dimer of 3.0 micrograms/ml or more, sensitivity was 84%, specificity was 96%, and accuracy was 90%. Based on these results, we concluded that TAT and D-dimer are extremely useful in screening for acute DVT.