Tunneling between dissimilar high-T(c) oxide superconductors.

We report the first successful fabrication and measurement of high-T(c) heterojunctions with different oxide electrodes, YBa(2)Cu(3)O(7-y) and Bi(2)Sr(2)CaCu(2)O(y). Different kinds of junction characteristics are observable according to the magnitude of the tunnel resistance. With higher tunnel resistance, gap structures corresponding to two gaps are clearly observed, ensuring that the conventional tunneling scheme is also valid for this geometry. Peculiar behavior for the zero bias conductance peak is also observable. Josephson current is found to flow between these dissimilar superconductors.

Diamagnetic activity above Tc as a precursor to superconductivity in La2-xSrxCuO4 thin films.

Superconductors show zero resistance to electric current, and expel magnetic flux (the Meissner effect) below the transition temperature (Tc). In conventional superconductors, the 'Cooper pairs' of electrons that are responsible for superconductivity form only below Tc. In the unconventional high-Tc superconductors, however, a strong electron correlation is essential for pair formation: there is evidence that some pairs are formed above Tc in samples that have less than the optimal density of charge carriers (underdoped) and an energy gap-the 'pseudogap'-appears to be present. Moreover, excitations that look like the vortices that carry magnetic flux inside the superconducting state have been reported above Tc (refs 6, 7). Although the origin of the pseudogap remains controversial, phase fluctuations above Tc, leading to some form of local superconductivity or local pairing, seem essential. Here we report magnetic imaging (scanning SQUID microscopy) of La2-xSrxCuO4 thin films. Clear quantized vortex patterns are visible below Tc (18-19 K), and we observe inhomogeneous magnetic domains that persist up to 80 K. We interpret the data as suggesting the existence of diamagnetic regions that are precursors to the Meissner state.

Growth factors: importance in wound healing and maintenance of transparency of the cornea.

The mechanism of corneal wound healing has not been clarified yet. However, evidence has accumulated that various kinds of growth factor such as epidermal growth factor (EGF), fibroblast growth factor (FGF), transforming growth factor (TGF), keratinocyte growth factor (KGF), hepatocyte growth factor (HGF), platelet-derived growth factor (PDGF) and insulin-like growth factor (IGF) play a key role in corneal wound healing. For example, these growth factors are expressed in the corneal epithelial cells, keratocytes and endothelial cells, and their receptors are expressed in the corneal cells. Furthermore, these growth factors promote the proliferation of corneal cells and induce the migration of corneal cells. In addition to the growth factors, inflammatory cytokines such as interleukin (IL)-1, IL-6 and TNF-alpha are involved in corneal wound healing. These cytokines are expressed in the normal and inflammatory cornea after infections, alkaliburn, etc. where they control the growth of corneal cells and induce the migration of corneal cells. Thus, a number of growth factors and cytokines function in the regulation of corneal cell proliferation and in the maintenance of corneal transparency.

Effects of PDGF on the migration of rabbit corneal fibroblasts and epithelial cells.

PURPOSE: We investigated the effects of human platelet-derived growth factor (PDGF) isomers on the migration of rabbit corneal fibroblasts and epithelial cells in the presence or absence of fibronectin (FN). METHODS: A modified Boyden's chamber method was used to detect cell migration. Cells placed in the inner chamber were incubated with PDGF in the outer chamber at 37 degrees C at 24 h. In addition, epithelial cells were incubated in the presence or absence of FN. The migrated cells were stained and the cell number counted under a microscope. Checkerboard analysis was used to distinguish chemotaxis from chemokinesis. RESULTS: Natural PDGF and PDGF-BB enhanced the migration of corneal fibroblasts, whereas PDGF-AA did not. As for corneal epithelial cells, all the isomers of PDGF enhanced the migration, but only in the presence of FN, as in the absence of FN or at a low concentration gradient of FN, there was no enhanced cell migration. A checkerboard assay demonstrated that PDGF-BB had a chemotactic effect on the migration of corneal fibroblasts and epithelial cells, whereas PDGF-AA had a chemotactic effect on only corneal epithelial cells. CONCLUSION: These results suggest that PDGF is involved in corneal wound healing by stimulating the migration of corneal epithelial cells in the presence of FN and fibroblasts.

New method for evaluation of hard contact lens materials with regard to cell injury by dynamic contact.

To establish a new method for evaluation of contact lens materials, we studied the porcine endothelial cell injury caused by dynamic contact (rotatory rubbing) with three kinds of hard contact lenses (HCL). The HCLs used were 1) PMMA HCL, 2) oxygen-permeable HCL composed of a graft copolymer of dextran derivative and methylmethacrylate (MMA) (Suncon Mild II, 12 Dk), and 3) oxygen-permeable-HCL composed of a copolymer of a monomer containing silicone, a monomer containing fluorine, and MMA (RGPL-A, 216 Dk). Cell injury rates were significantly different among these HCLs (Suncon Mild II < PMMA < RGPL-A) although there were no differences in rotatory rubbing forces. The smoothness of HCL surface, the qualities of injured cell layers observed by scanning electron microscopy, and the water wettability of HCLs were not correlated with cell injury rate. These results suggest that physicochemical properties of materials other than rotatory rubbing force, smoothness, and water wettability were involved in the cell injury. Our evaluation method for biomaterials that injure the corneal endothelial cells by dynamic contact should be very useful for the development of biomaterials or medical devices, including HCLs and intracardiac and urethral catheters.

Influence of dynamic contact of hard contact lens materials on corneal epithelial cells examined by rose bengal staining.

PURPOSE: To establish a method for evaluation of less irritating contact lens materials by dynamic contact with cornea, we examined epithelial and endothelial cell injury to the porcine cornea caused by rotatory rubbing with four kinds of hard contact lenses (HCL). METHODS: The HCLs used were (1) polymethylmethacrylate (PMMA) HCL, (2) gas-permeable HCL composed of a graft co-polymer of dextran derivative and methylmethacrylate (MMA) (Suncon Mild II(TM), 12 Dk), (3) gas-permeable HCL composed of a graft co-polymer of dextran derivative, a monomer containing silicone, a monomer containing fluorine and MMA (New Dx HCL-136, 32 Dk), and (4) gas-permeable HCL composed of a monomer containing silicone, a monomer containing fluorine and MMA(RGPL-A, 216 Dk). Using a specially designed apparatus, we produced a standardized injury to the epithelium or endothelium of porcine corneas by holding the HCL against the corneal surface while rotating the lens rapidly. RESULTS: After rotatory rubbing of the HCL on the epithelium, the degree of rose bengal staining of the epithelial cells, indicating degeneration of the cells and mucin detachment, were significantly different among these HCLs (New Dx HCL-136 < Suncon Mild II(TM), PPMA < RGPL-A), and the cell injury rates of the endothelium were also significantly different among them (Suncon Mild II(TM) < New Dx HCL-136, PMMA < RGPL-A). The water-wettability of HCLs was not directly correlated with cell injury rates on epithelial and endothelial cells. CONCLUSIONS: Both the New Dx HCL-136 and Suncon Mild II(TM), which have a common composition of graft co-polymer of dextran derivative, are less irritating to the epithelium and to the endothelium. Also a very few patients complaints regarding Suncon Mild II(TM) wearing in individuals with dry eyes have been reported. Therefore, we would expect that the New Dx HCL-136 should be satisfactory for wear by individuals with dry eyes.

Enhancing effect of platelet-derived growth factors on migration of corneal endothelial cells.

To investigate the role of platelet-derived growth factor (PDGF) in corneal wound healing, we examined the effect of human natural PDGF, recombinant PDGF-BB, and PDGF-AA on the migration of rabbit corneal endothelial cells. In a modified Boyden chamber in fetal bovine serum-free conditions, natural PDGF and PDGF-BB, at a concentration of 1-3 or 10 ng/ml, enhanced the migration of endothelial cells, whereas at a higher concentration (10 or 30 ng/ml), this enhanced migration was suppressed; the optimal concentration range for enhancing migration was 3-10 ng/ml. PDGF-AA did not enhance the migration. Natural PDGF and PDGF-BB activity was found for up to 6 h after the beginning of culture, and was completely blocked by anti-PDGF neutralizing antibodies. A checkerboard assay demonstrated that PDGF-BB had a chemotactic effect on the corneal endothelial cell migration. These results suggest that natural PDGF and PDGF-BB, but not PDGF-AA, are involved in corneal wound healing by stimulating the migration of corneal endothelial cells.

Enhancement of growth of rabbit corneal endothelial cells by PDGF.

The effect of platelet-derived growth factor (PDGF) on the growth of rabbit corneal endothelial cells and the expression of PDGF receptor mRNA in these cells were examined in the present study. When rabbit corneal endothelial cells were cultured in the presence of natural PDGF, recombinant PDGF-BB, and PDGF-AA for 1, 3, and 5 days, natural PDGF and recombinant PDGF-BB enhanced the growth of the endothelial cells, but PDGF-AA did not. This growth promotion was suppressed by anti-PDGF antibody. PDGF enhanced also the incorporation of 3H-thymidine into the cells. When PDGF was combined with epidermal growth factor (EGF), the additive effect was recognized. The expression of the PDGF receptor mRNA was found in the endothelial cells by the polymerase chain reaction (PCR) method. It was concluded from these results that PDGF enhanced the growth of the corneal endothelial cells and that the PDGF receptor mRNA was expressed in these cells. These results suggest that PDGF may regulate corneal endothelial cell growth.

Enhancement of fibronectin-induced migration of corneal epithelial cells by cytokines.

PURPOSE: To examine the enhancing effect of cytokines on the corneal epithelial cell migration induced by fibronectin (FN). METHODS: A modified Boyden chamber method was used to detect chemotactic cell migration. Cells plated in the inner chamber were incubated with FN, cytokines, or both in the outer chamber at 37 degrees C for 24 hours. Cells that had migrated were stained and counted under a microscope. Checkerboard analysis was used to distinguish chemotaxis from chemokinesis. RESULTS: FN induced epithelial cell migration, but interleukin (IL)-1 alpha, IL-6, tumor necrosis factor (TNF)-alpha, and epidermal growth factor (EGF) alone did not. These cytokines, even at very low concentrations (0.1 to 100 pg/ml), enhanced FN-induced migration to levels about twofold those observed with FN alone. Checkerboard analysis demonstrated that EGF, but not IL-1 alpha, IL-6, or TNF-alpha, stimulated the chemokinesis of corneal epithelial cells in the presence of FN. CONCLUSION: EGF enhanced corneal epithelial cell migration by increasing chemokinesis, whereas IL-1 alpha, IL-6, and TNF-alpha enhanced this migration by increasing the FN-induced chemotactic activity, although these cytokines themselves do not have chemokinetic and chemotactic activity.

Extent of pontine pyramidal tract Wallerian degeneration and outcome after supratentorial hemorrhagic stroke.

BACKGROUND AND PURPOSE: Pyramidal tract Wallerian degeneration has been detected on magnetic resonance imaging (MRI) as T2-weighted high-intensity areas. We analyzed the relation between the extent of brain stem Wallerian degeneration and activities of daily living (ADL) after supratentorial hemorrhagic stroke. METHODS: Twenty-six patients with supratentorial hemorrhage were examined on the coronal T2-weighted image of the pons 3 months or later after stroke, and the percentage of Wallerian degeneration in the pons was calculated. The patients were divided into three groups. In group A (n = 6), MR films were taken 3 to 6 months from the onset, and the ADL assessment was done within 2 months from the MRI. In group B (n = 11), MR films were taken 3 to 6 months from the onset, and the ADL assessment was done within 10 months from the MRI (mean, 15.5 months from the onset). In group C (n = 9), MR films were taken after 10 to 17 months (mean, 12.0 months) from the ictus, and the ADL assessment was done simultaneously. Barthel Index score was used for quantitative ADL assessment. RESULTS: All patients showed various degrees of pontine pyramidal tract Wallerian degeneration associated with capsular involvement by the hematoma. In group A, the percentage of degeneration did not correlate with the Barthel Index score (r = .2101, P = .6895). An inverse relation between percentage of degeneration and Barthel Index score was seen in groups B (r = .7354, P = .0099) and C (r = .888, P = .0014). In groups B and C, Wallerian degeneration was higher in patients with Barthel scores less than 60 (P = .005). CONCLUSIONS: The extent of pontine Wallerian degeneration on MRI 3 months or later after the stroke correlated with the patient's Barthel Index score 1 year after the stroke.

Asymptomatic syringomyelia associated with cerebellopontine angle meningioma--case report.

A 66-year-old female with a 3-year history of left trigeminal neuralgia presented with an unusual left cerebellopontine angle meningioma associated with asymptomatic syringomyelia at the C2 to C4 levels diagnosed by magnetic resonance (MR) imaging. Two months after total tumor removal, the syringomyelia had diminished without shunting. MR images are useful as a basis for early diagnosis of syringomyelia.

[A case of malignant melanoma with orbital metastasis which caused the first symptoms].

A thirty-four-year-old man was admitted to our hospital because of the disturbed visual acuity and pain on the eye movement of the right eye. He had prominent right eye and CT-scan and MRI of the brain disclosed a tumor which could be obviously distinguished from the extraocular muscles, optic nerve and the bulb of eye in the retrobulbar region. On operation we identified dark-red solid tumor which was 3.0cm in diameter, and diagnosed it malignant melanoma pathologically. Because postoperative study detected amelanotic melanoma in the white patch on the right upper extremity, this right orbital tumor was considered to be the metastasis of it from the right upper extremity. Metastatic malignant melanoma of the skin to the orbit is very rare, while most of the eye-associated malignant melanoma originates from uveal tract, special choroid, and conjunctiva. This case was the 26th case of these in the world and the first case in Japan, furthermore the 4th case in the world whose first symptoms were caused by the orbital metastasis.

Intracerebral leukemic mass in acute myelogenous leukemia.

Leukemic intracranial space occupying lesions are rare. A 69 year old man with acute myelogenous leukemia was found to have an intracranial leukemic mass at the time of his remission period. Computed tomography and magnetic resonance imaging study demonstrated a large irregular mass in the right temporal lobe. After total removal of the tumor, the patient was treated with whole brain irradiation and intrathecal chemotherapy. After surviving for 7 months, the patient expired of hematologic relapse.

Familial occurrence of moyamoya disease with intracranial hemorrhage--report of two cases.

The authors report an instance of familial moyamoya disease involving a 47-year-old female and her 18-year-old daughter, both of whom initially presented, within a 1-year period, with intracranial hemorrhage. Cerebral angiography showed the typical features of moyamoya disease. The mother, whose disease was more advanced, underwent superficial temporal-middle cerebral artery bypass, with satisfactory results. Human leukocyte antigen typing was performed in both cases. The pertinent literature is reviewed.

Capsule types of Klebsiella pneumoniae isolated from the genital tract of mares with metritis, extra-genital sites of healthy mares and the genital tract of stallions.

A survey of K. pneumoniae was performed on cervical swabs, feces and nasal swabs of mares and on samples from the genital tract of stallions from 1980 to 1986 in south-western Hokkaido, Japan. K1 was the predominant type (79 of 88, 89.8%) in the metritis cases due to K. pneumoniae in mares of racing breeds. The same type was isolated from semen and swabs of the fossa glandis of 6 of 20 (30.0%) of the stallions of racing breeds. Heavily encapsulated and less heavily encapsulated K1 strains were isolated from the stallions. Mares bred to stallions carrying heavily encapsulated strains developed metritis, while those bred to stallions carrying less heavily encapsulated strains did not. K39 was isolated from cervical swabs solely from metritis-infected mares of draft breeds and not from any mares of the racing breeds examined. Untypable strains were isolated from cervical swabs in 7 of 88 (8.0%) metritis cases of mares of racing breeds and from semen in 7 of 19 (36.8%) stallions of racing breeds and they were predominant in feces (19 of 21, 90.5%) and nasal swabs (3 of 4, 75.0%) of healthy mares of racing breeds.