Hemodynamic study on flow patterns in the carotid bifurcation before and after carotid endarterectomy using cine magnetic resonance imaging

Blood flow in the cervical carotid bifurcation was investigated by cine magnetic resonance imaging. In patients without stenosis, a low-intensity stream was demonstrated from the beginning of the carotid bulb, which was more distinct in the systolic phase. In patients with stenotic carotid bifurcations, the low-intensity flow was also present but was more prominent than in the non-stenotic bifurcation. This low-intensity stream may be due to the change from steady to turbulent flow due to the geometric characteristics of the carotid bifurcation or atheromatous plaque, similar to the flow separation phenomenon in fluid dynamics because of the coincidence of location and flow pattern. After carotid endarterectomy, turbulent flow was seen at the proximal and distal ends of the endarterectomy. Close follow-up and administration of antiplatelet agents are necessary to prevent restenosis due to mural thrombosis induced by such turbulent flow.

Odorant-regulated Ca2+ gradients in rat olfactory neurons

Olfactory neurons respond to odors with a change in conductance that mediates an influx of cations including Ca2+. The concomitant increase in [Cai] has been postulated to play a role in the adaptation to maintained odorant stimulation (Kurahashi, T., and T. Shibuya. 1990. Brain Research. 515:261-268. Kramer, R. H., and S. A. Siegelbaum. 1992. Neuron. 9:897-906. Zufall, F., G. M. Shepherd, and S. Firestein. 1991. Proceedings of the Royal Society of London, B. 246:225-230.) We have imaged the distribution of [Cai] in rat olfactory neurons (RON) using the Ca2+ indicator fura-2. A large percentage of the RON (42%, n = 35) responded to odorants with an increase in [Cai]. About half of the responding neurons displayed an increase in [Cai] at the apical end of the cell, but not at the soma. Moreover, in those cells that responded to odors with a standing [Cai] gradient, the gradient could be maintained for long periods of time (minutes) provided that the cells were continuously stimulated. In contrast, K(+)-induced depolarization elicited a more homogeneous increase in [Cai]. The spatially inhomogeneous increase in [Cai] elicited by odorants in some cells has important implications for the role of Ca2+ in adaptation because channels and enzymes regulated by Ca2+ will be affected differently depending on their location.

K+ channel-opening action and KRN2391-induced reduction of Ca2+ sensitivity of arterial smooth muscle

To clarify the vasodilating mechanism of KRN2391, a novel vasodilator having a combined nitrate-like and K+ channel-opening action, we investigated its effects on membrane potentials, intracellular Ca2+ concentrations ([Ca2+]i) and force of contraction in canine coronary artery. KRN2391 hyperpolarized the membrane of arterial smooth muscle cells in 5 and 30 mM KCl-physiological salt solutions. KRN2391 reduced the increases in [Ca2+]i and force of contraction induced by 30 mM KCl-physiological salt solution and the effect on [Ca2+]i was almost abolished by 10(-5) M glibenclamide, although the effect on force of contraction was only partially inhibited. The [Ca2+]i-force curves in the presence of KRN2391 or the selective K+ channel openers Ki4032 and cromakalim were shifted to the right, as compared to the control curve determined by varying the extracellular Ca2+ concentration ([Ca2+]o). This finding indicates that these substances reduce the Ca2+ sensitivity of contractile elements (Ca2+ desensitization). The Ca(2+)-desensitizing action of KRN2391 was partly antagonized by 10(-5) M glibenclamide. There was no interaction between nitroglycerin and cromakalim or Ki4032. These results suggest that, in addition to the nitrate-like action, the opening of the K+ channel by KRN2391 reduces not only [Ca2+]i but also the Ca2+ sensitivity of contractile elements, resulting in vasodilatation.

Selective impairment of the cytoplasmic Ca2+ response to glucose in pancreatic beta cells of streptozocin-induced non-insulin-dependent diabetic rats

Pancreatic islets from the streptozocin-induced non-insulin-dependent diabetes mellitus (NIDDM) rat model showed a diminished insulin response to 16.7 mmol/L glucose, but the insulin response to arginine remained intact. To evaluate the importance of intracellular calcium concentration ([Ca2+]i) in the diminished insulin response to glucose, the [Ca2+]i of pancreatic beta cells was investigated using fura-2. Glucose produced heterogeneous responses of [Ca2+]i, which were in beta-cell clusters of both the control and NIDDM groups. Many cells showed initial slight decreases of [Ca2+]i, which were followed by gradual and large increments of [Ca2+]i after glucose stimulation of beta cells in the control group. On the other hand, the increase of [Ca2+]i in response to glucose was markedly diminished in beta cells of the NIDDM group compared with controls. The average lag time to [Ca2+]i elevation of beta cells in the NIDDM group was significantly longer than that of the control group. Arginine produced marked increases of [Ca2+]i, in contrast to the effect of glucose stimulation in the NIDDM group. These results suggest that the diminished and delayed [Ca2+]i increases in beta cells of NIDDM rats in response to glucose stimulation are responsible for the selectively impaired insulin response to glucose in the rat model of NIDDM.

Mechanism of action of KRN2391 in canine coronary vascular bed

The present studies were performed to clarify the mechanism of action of KRN2391 in various sizes of canine coronary artery. We used the responses of isolated large and small coronary arteries and the changes in coronary blood flow (CBF) as indicators reflecting the responses of conductive arteries and resistive arterioles, respectively. In isolated small coronary artery, the effect of KRN2391 (10(-8)-10(-5) M) was antagonized by either methylene blue or glibenclamide. In isolated large coronary artery, the vasorelaxant effect of KRN2391 (10(-8)-10(-5) M) and nicorandil (10(-7)-10(-4) M) were antagonized by methylene blue (10(-5) M) but not by glibenclamide (10(-6) M). The relaxant effect of cromakalim was antagonized by glibenclamide but not by methylene blue in isolated large coronary artery. Intracoronary arterial injection of KRN2391, nicorandil or cromakalim produced an increase in CBF dose-dependently. Glibenclamide (5 mg/kg, i.v.) attenuated the increase in CBF caused by KRN2391, nicorandil and cromakalim. ED20, the dose that produced an increase in CBF by 20 ml/min, increased about 5-fold for KRN2391 and nicorandil and about 12-fold for cromakalim after administration of glibenclamide. These results suggest that the mechanism of action of KRN2391 and nicorandil depends on the segment of coronary arteries; i.e., they show a nitrate action alone in large coronary artery, and a K-channel opening action in addition to a nitrate action as the size of the coronary artery decreases.

WS1279, a novel lipopeptide isolated from Streptomyces willmorei. Biological activities

WS1279, a new lipopeptide isolated from the fermentation broth of Streptomyces willmorei No. 1279, stimulated the proliferation of mouse bone marrow cells in vitro and accelerated the recovery of granulocyte counts in bone marrow from leukopenia induced by mitomycin C (MMC) in mice. The glycerylcysteine moiety of WS1279 is necessary and the lipid peptide structure is required for manifestation of full stimulating activity in vitro. WS1279 was the most effective on the proliferation of bone marrow cells among the tested immunostimulants in vitro. However, the effect of WS1279 on restoration of reduced granulocyte counts in MMC-induced leukopenia in mice was less than that of FK-565, lipopolysaccharide, picibanil or forphenicinol. WS1279 augmented host resistance to infection with Staphylococcus aureus 47 in normal and immunosuppressed mice.

Amino acids and peptides. XXXVI. Synthesis of enkephalin chloromethyl ketone and evaluation of its inhibitory activity against endopeptidase 22.19

Boc-Tyr-Gly-Gly-Phe-Leu-Ch2Cl was synthesized by the conventional solution method. During the course of acid hydrolysis (6N HCl, 110 degrees C, 18h) of Boc-Phe-Leu-CH2Cl, side reaction occurred, resulting in low recovery of Phe residue on amino acid analysis. The inhibitory activity of the synthesized Boc-Tyr-Gly-Gly-Phe-Leu-CH2Cl against endopeptidase 22.19, an enzyme related to the metabolism of opioid peptides, was examined.

A one-step sandwich enzyme immunoassay for tissue inhibitor of metalloproteinases-2 using monoclonal antibodies

A one-step sandwich enzyme immunoassay system was developed with a pair of monoclonal antibodies against two individual oligopeptides prepared from the amino acid sequence of the human tissue inhibitor of metalloproteinases-2 (TIMP-2). The assay system consisting of two simultaneous immunoreactions used a solid phase monoclonal antibody and a horse-radish peroxidase-labeled monoclonal antibody. The system detected a free form of TIMP-2 and that complexed with active forms of matrix metalloproteinases (MMPs) giving a different sensitivity for each MMP but not TIMP-2 complexed with the precursor of 72 kDa gelatinase/type IV collagenase (MMP-2). The sensitivity of the system was 1.6 microgram/l (16 pg/assay) and linearity was obtained between 6.3 and 50 micrograms/l (63-500 pg/assay). TIMP-2 levels in the sera of 20 patients with rheumatoid arthritis (68 +/- 25 micrograms/l, mean +/- S.D.) and 13 patients with hepatocellular carcinoma (76 +/- 46 micrograms/l) were significantly higher (P < 0.05) than those of 18 normal subjects (5.6 +/- 7.4 micrograms/l). In contrast, the levels in the sera of 10 patients with gastric cancer (45 +/- 18 micrograms/l) and 7 patients with cancer of the uterus (36 +/- 13 micrograms/l) were significantly lower (P < 0.05 or P < 0.01) than those of normal subjects. Immunoreactivity analyses suggested that the precursor of MMP-2 in normal sera exists in a complexed form with TIMP-2 by interacting with the C-terminal domain of TIMP-2.

Use of the hemagglutinating virus of Japan (HVJ)-liposome method for analysis of infiltrating lymphocytes induced by hepatitis B virus gene expression in liver tissue

We previously developed a method for introducing foreign genes into liver tissue using liposomes with incorporated hemagglutinating virus of Japan (HVJ, Sendai virus), and found that liver cells transfected with the E. coli beta-galactosidase gene or the gene for hepatitis B virus (HBV) surface protein (HBsAg) expressed these proteins in vivo. Here, we analyzed cellular reactions leading to hepatitis in the liver by expressing the genes of HBV in vivo. Lymphocytes were eluted directly from liver transfected with the HBsAg genes and shown to be cytotoxic only to cells expressing HBsAg in vitro. These lymphocytes were identified as cytotoxic T lymphocytes with the CD4- CD8+ phenotype. Transfer of these lymphocytes to transgenic mice with the whole HBV genome led to elevation of the serum glutamic-pyruvic transaminase (SGPT) level, indicating the induction of hepatitis due to the cytotoxic T lymphocytes in vivo. Similarly, direct transfer of the gene for the HBV secretory core protein (HBeAg) induced expression of HBeAg in hepatocytes and the appearance of antibody against HBeAg in the serum. However, using this system, we found that the lymphocytes infiltrating the transfected liver showed no cytotoxicity specific for HBeAg. These results indicate that expression of HBsAg, one of the components of virions, in animal liver induced hepatitis efficiently through generation of specific cytotoxic T lymphocytes (CTL) without any expression of the other viral components. This in vivo experimental system should be useful for evaluating how expression of a given gene induces cellular reactions and intrinsic functions in the living body.

A one-step sandwich enzyme immunoassay for human matrix metalloproteinase 1 (interstitial collagenase) using monoclonal antibodies

Interstitial collagenase (EC 3.4.24.7, matrix metalloproteinase-1, MMP-1) is synthesized and secreted by many cells, and plays an important role in a wide variety of pathophysiological degradation processes of extracellular matrices. The activity of MMP-1 is regulated by tissue inhibitors of metalloproteinases, TIMP-1 or TIMP-2, which form a non-covalent complex with the active enzyme. We raised monoclonal antibodies against zymogen of MMP-1, proMMP-1 purified from human skin fibroblasts. The antibodies recognized both precursor and active forms of MMP-1, but did not cross-react with 72-kDa and 92-kDa gelatinase/type IV collagenases or stromelysin-1. A specific and sensitive one-step sandwich enzyme immunoassay for human MMP-1 was developed using a solid phase monoclonal antibody and a horseradish peroxidase-labeled monoclonal antibody (Fab'). The assay can be completed within 1 h (30 min for immunoreaction and 15 min for color development) and the sensitivity is 0.12 microgram/l with the linearity between 0.12 and 10 micrograms/l. Active MMP-1 shows 1.3-fold higher absorption at 492 nm than proMMP-1. However, the recognition rate of MMP-1 is decreased to approximately 50% and < 3% for the MMP-1-TIMP-1 and MMP-1-TIMP-2 complex forms, respectively. The MMP-1 levels in human sera from 120 healthy subjects are shown to be in the range of 8.5 +/- 5.2 micrograms/l (mean +/- S.D.) and the levels of 95% of the samples range from 0 to 20 micrograms/l.

Magnetic resonance imaging study on the results of surgery for cervical compression myelopathy

The morphologic changes and signal intensity of the spinal cord on preoperative magnetic resonance images were correlated with postoperative outcomes in 74 patients undergoing decompressive cervical surgery for compressive myelopathy. The transverse area of the spinal cord on T1-weighted images at the level of maximum compression was closely correlated with the severity of myelopathy, duration of disease, and recovery rate as determined by the Japanese Orthopaedic Association score. In patients with ossification of the posterior longitudinal ligament or cervical spondylotic myelopathy, the increased intramedullary T2-weighted magnetic resonance imaging signal at the site of maximal cord compression and duration of disease significantly influenced the rate of recovery. A multiple regression equation was then developed with these three variables to predict surgical outcomes.

Exocrinopathy resembling Sjögren's syndrome induced by a murine retrovirus

BACKGROUND

Sjögren's syndrome (SS) is characterized by lymphocytic infiltration into, and destruction of exocrine glands, resulting in dryness of the mouth and eyes. The disease is considered to have an autoimmune etiology, however, its etiopathogenesis remains largely unknown. Recently, retrovirus is suggested to participate in the pathogenesis of SS, because SS-like lesions are reported in HIV infection or in human T cell leukemia virus type I infection. Moreover, human intracisternal A-type retroviral particles are reported to be detected in SS patients. During the course of our study on the histopathology of mice infected with a murine retrovirus, we happened to find SS-like exocrinopathy in those mice.

EXPERIMENTAL DESIGN

Four-week-old C57BL/6 (B6) mice were injected intraperitoneally with LP-BM5 murine leukemia virus. This virus is known to induce splenomegaly, lymphadenopathy followed by lymphoid malignancy, and profound immunodeficiency in sensitive strains of mice. From 4 to 16 weeks after the virus inoculation, the infected mice were sacrificed and their submandibular and lacrimal glands were analyzed light and electron microscopically and immunohistochemically. The existence of the virus in the lesion in situ was also analyzed by the same method, and additionally by a polymerase chain reaction method.

RESULTS

Periductal lymphocytic infiltration into the submandibular and lacrimal glands was observed in all the virus-infected mice at 4 weeks after the infection and progressed with time. Extraglandular lymphocytic infiltration was also observed in liver, kidney, lung, and pancreas. Immunohistochemical examination revealed that most infiltrating cells into the glands were composed of CD3+ T cells (CD4-dominant), Mac-1+ cells, and B220+ cells. The virus genome was detected in submandibular glands by immunohistochemistry or by polymerase chain reaction. In addition, retroviral particles were secreted into the lumen of exocrine ducts of submandibular glands.

CONCLUSIONS

This might be an SS animal model that is induced by a certain defined retrovirus. This experimental system might provide us with valuable information for analyzing the mechanisms of how a retrovirus could induce SS.

Glucose sensitivity of ATP-sensitive K+ channels is impaired in beta-cells of the GK rat. A new genetic model of NIDDM

In the Goto-Kakizaki rat, a new genetic model of NIDDM, insulin response to glucose is selectively impaired. To elucidate the mechanism of this abnormality, we studied the properties of ATP-sensitive K+ channels, the inhibition of which is a key step of insulin secretion induced by fuel substrates, using the patch-clamp technique. The glucose-sensitivity of KATP channels was considerably reduced in GK rats. However, the inhibitory effects of ATP on channel activity and unitary conductance were not significantly different between control and GK rats. Thus, it appears that the impaired insulinotropic action of glucose in beta-cells of GK rats is attributable to insufficient closure of the KATP channels, probably because of deficient ATP production by impaired glucose metabolism. KATP-channel activities in both control and diabetic beta-cells were found to be equally suppressed by glyceraldehyde and 2-ketoisocaproate. These results strongly suggest that the step responsible for the metabolic dysfunction of diabetic beta-cells is located within the glycolytic pathway before glyceraldehyde-3-phosphate or in the glycerol phosphate shuttle.

[Immunohistochemical study of c-erbB-2 proto-oncogene product in prostatic cancer]

The c-erbB-2 proto-oncogene product is expressed in adenocarcinomas of breast cancer and ovarian cancer, and its significance as a prognostic factor has been increasingly noted. We immunohistochemically studied the expression of c-erbB-2 proto-oncogene product using anti-c-erbB-2 gene product polyclonal antibody (Nichirei), which was produced using a synthetic peptide at the C-terminal portion as the immunogen. The subjects consisted of 52 patients with prostatic cancer who were treated at the Department of Urology, Shiga University of Medical Science, from 1982 to 1990. The expression of c-erbB-2 gene was observed in 40 of the 52 patients (76.9%). The positive rate was highest in patients with poorly differentiated cancer and in stage D2 patients, but there were no significant differences in positive rates among patients with different histological types or clinical stages. The probability that progression would occur was significantly (p < 0.05) lower in the group that tested positive for c-erbB-2 than in the group that tested negative among 33 stage D2 patients after 5 years of treatment. When cause specific survival rates were calculated using the Kaplan-Meier method, the group that tested positive had a significantly (p < 0.001) poorer outcome than the group that tested negative after 3 years and 6 months of treatment. The above results suggest that c-erbB-2 expression in prostatic cancer may be useful in predicting the prognosis of the disease.

Cytolytic activity of intestinal intraepithelial lymphocytes in germ-free mice is strain dependent and determined by T cells expressing gamma delta T-cell antigen receptors

We have compared the cytolytic activities and the cellular compositions of the intestinal intraepithelial lymphocyte (i-IEL) populations in three different combinations of conventional (CV) and germ-free (GF) mice. Cytolytic activity of i-IELs expressing gamma delta T-cell antigen receptors (TCRs) is strain dependent in CV mice (high vs. low), and this strain-dependent variability is unaltered in the GF condition. Although absolute numbers of gamma delta i-IELs are slightly decreased, the composition of CD8 alpha alpha+ and CD4-CD8- subsets and the usage of TCR gamma- and delta-chain variable gene segments by gamma delta i-IELs remain the same in GF mice. By contrast, cytolytic activity of alpha beta TCR-expressing i-IELs is uniformly high in CV mice but attenuated sharply in the GF condition. A conspicuous decrease in the total numbers of alpha beta i-IELs is also noted, and CD8 alpha beta+ and CD4+CD8+ subsets are reduced, whereas the CD8 alpha alpha+ subset is expanded in GF mice. These results indicate that microbial deprivation preferentially influences the alpha beta i-IEL population to decrease and become noncytolytic but has little effect on the pool size or characteristics of gamma delta i-IELs. Consequently, cytolytic activity of freshly isolated i-IELs from GF mice is determined by T cells expressing gamma delta TCRs and is found to be strain dependent.

Vasorelaxant action of Ki1769, a new pyridinecarboximidamide, in isolated porcine coronary artery

The characteristics of KRN2391 (N-cyano-N'-(2-nitroxyethyl)-3-pyridinecarboximidamide monomethansulfonate) and its phenethyl and 2-hydroxyethyl derivatives (Ki1769 and Ki3315) were studied in isolated porcine coronary arteries. KRN2391, Ki1769 and Ki3315 produced concentration-dependent relaxation of coronary arteries contracted by 25 mM KCl and the order of relaxant potency was KRN2391 > Ki1769 > Ki3315. At the maximum effect, KRN2391 produced nearly complete relaxation but Ki1769 produced about 66% relaxation. The maximum effect of Ki3315 could not be obtained because of its solubility. The relaxation induced by KRN2391 was antagonized by glibenclamide and methylene blue but relaxations caused by Ki1769 and Ki3315 were antagonized by glibenclamide alone. The antagonistic effect of glibenclamide on Ki1769- and Ki3315-induced relaxations was more potent than that on KRN2391-induced relaxation. KRN2391 induced relaxation of coronary arteries contracted by 40 mM KCl in a concentration-dependent manner but the effect of KRN2391 was smaller against 40 mM KCl-induced contractions than against 25 mM KCl-induced contractions. Ki1769 had almost no effect on coronary arteries contracted by 40 mM KCl. These results suggest that pyridinecarboximidamide derivatives which do not possess a nitroxyl group have vasodilating ability based on a K+ channel opening action.

Depth profiles of pH and PO2 in the isolated brain stem-spinal cord of the neonatal rat

We have measured depth profiles of extracellular pH (pHECR) and PO2 (PtO2) as well as the kinetics of changes of pHECR in the isolated brain stem-spinal cord preparation of the neonatal rat using pH and PO2 microelectrodes that entered from the ventral surface. When the preparation was superfused with control mock cerebrospinal fluid (Control mock CSF; pH = 7.5, PO2 = 630 Torr, PCO2 = 28 Torr, at 27 degrees C), the pH in the medulla diminished with a nearly constant gradient from the surface to a depth of about 1000 microns, the slope being about 0.1 pH unit per 100 microns. A similar gradient in the 200 to 300 microns of the CSF above the surface suggested existence of unstirred layers despite continuously flowing superfusate. The pH gradient in the spinal cord was somewhat smaller than that in the medulla. The PO2 gradients in both medulla and spinal cord were about 100 Torr per 100 microns from 200 microns above to 100 to 200 microns below the surface; PO2 reached zero at about 450 (medulla) to 600 microns (spinal cord). Although the preparation was anoxic and acidic except for a small layer below the surface, respiratory activity was recorded for several hours in C4 phrenic roots. The kinetics of changes in pHECF were recorded at 100 and 200 microns depth while rapidly replacing the control mock CSF by more acidic CSF, either with increased PCO2 ("Respiratory acidosis") or by adding fixed acid ("Metabolic acidosis"). The changes in pHECF were smaller than those in pHCSF, particularly during respiratory acidosis, as a result of the buffering of the brain tissue. Our results show the importance of superficial layers of the ventral medulla in producing respiratory rhythmicity; they further suggest that somewhat alkaline CSF (pH about 7.8) should be used in this preparation to ensure physiologic surface pH values despite unstirred surface layers.

Hypercapnia and medullary neurons in the isolated brain stem-spinal cord of the rat

We have extracellularly recorded single neuron activity in the ventral medulla of the isolated brain stem-spinal cord preparation of the neonatal rat (37 preparations) in order to test their sensitivity to changes in CO2/H+. Search for neuronal activity was performed when the preparation was superfused with control mock CSF (equilibrated with 2% CO2, 90% O2 in N2; pH = 7.8 at 27 degrees C). Neurons, found down to about 500 microns from the surface, could be classified as R neurons when they showed rhythmic discharge in phase with phrenic activity, recorded from C4 ventral roots; or as Non-R neurons when they did not exhibit such phasic discharge. Among the 89 Non-R neurons, 20 responded to rapidly replacing the control CSF by hypercapnic CSF (8% CO2, 90% O2 in N2; pH = 7.2) with increased, 44 with reduced activity, while 25 did not respond to hypercapnia. Five Non-R neurons became phasic with respiration during hypercapnia. Of the 14 R neurons, 10 fired predominantly in expiration (R-E), 4 in inspiration (R-I). Only one R-E and two R-I neurons were excited by hypercapnia, the remaining were either inhibited or did not respond. Excited Non-R and R neurons were mainly encountered in rostral parts of those areas in the ventral medulla that have been reported as chemosensitive.

Voltage clamping of a frog (Rana catesbeiana) taste cell with a single microelectrode

1. Receptor currents in frog taste cells induced by taste stimuli of NaCl and HCl were studied in situ using a voltage clamp method with a single microelectrode. 2. Under voltage clamping of a taste cell at -20 mV an inward receptor current of a mean of 176 pA was induced by taste stimulation with 0.5 M NaCl and the input resistance was largely reduced during the stimulation. 3. A large sustained inward current was evoked by HCl stimulation but the input resistance was slightly reduced. 4. Increasing the holding potential in the negative direction linearly increased the inward receptor current by NaCl stimulation but did not remarkably change it by HCl stimulation.

Epithelial basement membrane in alkali-burned corneas in rats. Immunohistochemical study

We investigated the altered immunolocalization of the components of epithelial basement membrane (BM) in rats with alkali burns of the cornea. Type IV collagen, laminin, and fibronectin were immunohistochemically stained in the alkali-burned corneas after various intervals. Linear laminin immunoreactivity, which represented the localization of the BM, was interrupted, probably by epithelial enzymes, under the regenerating epithelium after 24 h. A normal configuration was restored on day 7, when the central corneal BM showed a type IV collagen immunoreactivity that was not detected in BM of normal cornea. The exact cause of the development of type IV collagen immunoreactivity in the healing BM was not determined. Laminin, type IV collagen, and fibronectin, which were not detected in normal stroma, were all detected in the healing corneal stroma with repopulated keratocytes. Moreover, the BM zone under the regenerating epithelium showed fibronectin immunoreactivity on days 5-14. Distribution of these components of BM seemed to be normal 2 months postburn. The alteration of BM components is thought to be an important marker of the healing process in corneas burned with alkali.

Nucleotide sequence of tobamovirus Ob which can spread systemically in N gene tobacco

The genomic RNA sequence of tobamovirus Ob (Ob), which can spread systemically in tobacco carrying the N gene, was determined. It consists of 6507 nucleotides and contains four open reading frames, exactly corresponding to the genomic organization of tobamoviruses known so far, i.e. encoding the 130K, 180K, 30K and coat proteins. There were no nucleotide overlaps between any open reading frames. The Ob nucleic acid sequence, predicted protein sequences and gene organization were compared with those of other tobamoviruses reported previously. This virus was originally reported as a tomato mosaic virus; however, the nucleotide sequence data given here refute this classification. The determinants that allow tobamovirus Ob to overcome the N gene, a feature peculiar to this virus, were not identified apart from sequence data. This virus should be regarded as a new tobamovirus. The determinants interacting with the tentative N gene product have not yet been analysed.

An elastinolytic enzyme detected in the culture medium of human arterial smooth muscle cells

The culture medium of human arterial smooth muscle cells exhibits an elastinolytic activity with 68 and 64 kDa on elastin substrate gels. The enzymatic activities are inhibited by ethylenediamine tetraacetic acid, a metalloproteinase inhibitor, but not by other inhibitors of serine, cysteine and aspartic proteinases. The proteinase in the culture medium is activatable by 4-aminophenylmercuric acetate and degrades insoluble elastin. Compared to other matrix metalloproteinases (MMP), the activity shows the similar elastinolytic pattern to that by MMP-2 purified from human rheumatoid synovium, while MMP-3 and MMP-9 have different lytic patterns and MMP-1 possesses no elastinolytic activity. An immunoblot analysis demonstrated that the 68-kDa enzyme is MMP-2. An immunofluorescence study illustrates that MMP-2 is localized within the cytoplasm of the smooth muscle cells. These findings suggest that the elastinolytic enzyme secreted by human arterial smooth muscle cells is MMP-2.