Reagent-free crosslinking of aqueous gelatin: manufacture and characteristics of gelatin gels irradiated with gamma-ray and electron beam

In order to obtain a gelatin hydrogel crosslinked by a reagent-free method, gamma-ray and electron beam radiation was applied to porcine, bovine and fish gelatin gels and the products were characterized by measuring the gel fraction, the swelling ratio and the enzymatic degradability. On increasing the radiation dose, the gel fraction increased and both the swelling ratio and the enzymatic degradability decreased. The transition temperature from gel to sol of the hydrogel containing more than 5% mammal gelatins increased up to more than 90 degrees C when gamma-ray or electron beam were irradiated by more than 10 kGy. The results show that the degree of crosslinking of irradiated gelatin hydrogels increases with increasing irradiation dose and with decreasing concentration. It is suggested that the radiation crosslinking occurs around the physical crosslinking point or multiple helix structure of gelatin gel.     

Human myometrial cells in culture express specific binding sites for urinary trypsin inhibitor

Urinary trypsin inhibitor (UTI), which is present in amniotic fluid, prevents uterine contractility during pregnancy possibly via specific binding protein mechanisms. To test for the presence of UTI binding sites on the cell surface, we prepared cultured myometrial cells obtained at biopsy from 12 pregnant women and performed binding, competition, and cross-linking experiments using a specific radiolabelled UTI as a ligand. We report for the first time two classes of binding sites of differing affinities. Scatchard analysis at 4 degrees C, using radioiodinated UTI, revealed that UTI binds to 35 000 high affinity binding sites/cell (K(d) = 9.1x10(-9) mol/l) and 450 000 lower affinity binding sites/cell (K(d) = 3.5x10(-7) mol/l) in cultured myometrial cells. It appears to be the low affinity site that is internalized, and this has been identified as a protein of approximately 45 kDa by cross-linking and immunoaffinity labelling studies. Monoclonal antibodies against the NH(2)-terminal fragment of UTI abrogated specific binding of this protein to the cells. Treatment of the cells with hyaluronidase resulted in >80% inhibition of the [(125)I]-labelled UTI binding to the cells. These data show that the UTI binding site, which is hyaluronidase sensitive, is expressed on the surface of human uterine myometrial cells to accumulate the UTI molecule during pregnancy.     

Proteomics analysis of the centromere complex from HeLa interphase cells: UV-damaged DNA binding protein 1 (DDB-1) is a component of the CEN-complex, while BMI-1 is transiently co-localized with the centromeric region in interphase

CENP-A, a centromere-specific histone H3, is conserved throughout eukaryotes, and formation of CENP-A chromatin defines the active centromere region. Here, we report the isolation of CENP-A chromatin from HeLa interphase nuclei by chromatin immunoprecipitation using anti-CENP-A monoclonal antibody, and systematic identification of its components by mass spectrometric analyses. The isolated chromatin contained CENP-B, CENP-C, CENP-H, CENP-I/hMis 6 and hMis 12 as well as CENP-A, suggesting that the isolated chromatin may represent the centromere complex (CEN-complex). Mass spectrometric analyses of the CEN-complex identified approximately 40 proteins, including the previously reported centromere proteins and the proteins of unknown function. In addition, we unexpectedly identified a series of proteins previously reported to be related to functions other than chromosome segregation, such as uvDDB-1, XAP8, hSNF2H, FACTp180, FACTp80/SSRP1, polycomb group proteins (BMI-1, RING1, RNF2, HPC3 and PHP2), KNL5 and racGAP. We found that uvDDB-1 was actually localized to the centromeric region throughout cell cycle, while BMI-1 was transiently co-localized with the centromeres in interphase. These results give us new insights into the architecture, dynamics and function of centromeric chromatin in interphase nuclei, which might reflect regulation of cell proliferation and differentiation.     

Pulmonary synovial sarcoma with polypoid endobronchial growth: a case report, immunohistochemical and cytogenetic study

A rare case of primary pulmonary synovial sarcoma with polypoid endobronchial growth in a 42-year-old Japanese woman is described. Left upper sleeve lobectomy was performed for the polypoid tumor measuring 2.5 cm in the left major bronchus and the patient was treated with adjuvant chemotherapy. Three years later, a recurrent tumor was discovered. Microscopically, this tumor was characterized by a proliferation of oval to spindle-shaped cells arranged in sheets and fascicles and covered by the thin normal bronchial epithelium. Immunohistochemically, tumor cells were positive for vimentin, and focally positive for pancytokeratin recognized by AE1/AE3, cytokeratin 7 and epithelial membrane antigen. A chimera gene, SYT-SSX1, was detected. Recently, primary pulmonary synovial sarcoma is an increasingly recognized clinical entity; however, most of these tumors present as a parenchymal mass. The present case is a unique example of primary synovial sarcoma of endobronchial polypoid type. This case suggests that pulmonary synovial sarcoma might originate from bronchial submucosal stromal tissue.     

Ontogeny of plasma cells in the early rat yolk sac

The present study investigated the development of plasma cells in the early rat yolk sac (days 10-16 of gestation) by light microscopy, transmission electron microscopy, immunoelectron microscopy, and indirect immunofluoresce techniques. Cells delineating the morphology of plasma cells in the yolk sac were observed as early as 12 days of embryonic life. As for positive immune staining for the intra-cytoplasmic immunoglobulin (Ig) production (IgA, IgM and IgG), the intensity of the immune staining was very weak on days 10 and 11 of gestation, while it turned very dense on day 12 of gestation. At 14 days of gestation, the number of positive cells was markedly reduced. Immunoelectron microscopy visualized products of the immune reaction in cisterns of the rough endoplasmic reticulum. Conventional electron microscopic examination of 12, 13, and 16-day yolk sacs confirmed the development and differentiation of plasma cells with their well-known ultrastructural features, making this the first study to demonstrate these in the early rat yolk sac. The development of plasma cells in the early yolk sac implies the ability of the yolk sac to effect a humoral immune response at this stage of fetal life. The probable role of plasma cells in the yolk sac is also discussed.     

Malignant nerve sheath tumor of acoustic nerve

A malignant nerve sheath tumor of the acoustic nerve was found in a 54-year-old man whose right acoustic nerve signs had shown gradual worsening during the previous five years. No stigmata of von Recklinghausen's disease were noted. The tumor at autopsy extensively involved the brain stem, cerebellar hemisphere, tentorium of cerebellum, and cerebral occipitotemporal lobe on the right side. Histologically, the tumor was characterized by extreme hypercellularity, pleomorphism, and high mitotic activity. Ultrastructurally, there was an external lamina around the interdigitated cytoplasm of the tumor cells. Long-spacing collagens and junctional devices were also noted. This case is, to our knowledge, the first reported of a malignant nerve sheath tumor in the acoustic nerve.     

The antiallergic agent amoxanox suppresses SRS-A generation by inhibiting lipoxygenase

Amoxanox has potent antiallergic activity because it inhibits the release of chemical mediators such as histamine and leukotrienes. We studied the in vitro effect of amoxanox on arachidonic acid metabolism, including the lipoxygenase and cyclooxygenase pathways. Amoxanox inhibited calcium ionophore A23187-induced formation of 5-HETE, LTB4, SRS-A (LTC4, LTD4 and LTE4), and 12-HETE in rat peritoneal resident monocytes. These results indicate that amoxanox inhibits 5- and 12-lipoxygenases. The compound, however, did not affect the formation of TXB2 or 6-keto-PGF1 alpha in guinea pig lung fragments and PGE2 or PGF2 alpha in bovine seminal vesicles, suggesting that it did not inhibit cyclooxygenase. These results show that the antiallergic action of amoxanox is associated, at least in part, with the reduction of leukotrienes due to the inhibition of lipoxygenases.     

Engagement of gaze in capturing targets for future sequential manual actions

We investigated the role of saccadic gaze fixations in encoding target locations for planning a future manual task consisting of a sequence of discrete target-oriented actions. We hypothesized that fixations of the individual targets are necessary for accurate encoding of target locations and that there is a transfer of sequence information from visual encoding to manual recall. Subjects viewed four targets presented at random positions on a screen. After various delays following target extinction, the subjects marked the remembered target locations on the screen with the tip of a hand-held stick. When the targets were presented simultaneously among distracting elements, the overall accuracy of marking increased with presentation time and total number of targets fixated because the subjects had to serially fixate the individual targets to locate them. Without distractors, the marking accuracy was similarly high regardless of duration of target presentation (0.25-8 s) and number of targets fixated; it was comparable to that with distractors when all four targets had been fixated. This indicates parallel encoding of target locations largely based on peripheral vision. Location memory was stable in these tasks over the delay periods investigated (0.5-8 s). With parallel encoding there was a "shrinkage" in the visuomotor transformation, i.e., the distances between the markings were systematically smaller than the corresponding inter-target distances. When the targets were presented sequentially without distractors, marking accuracy improved with the total number of targets fixated and shrinkage in the visuomotor transformation occurred only with parallel encoding, i.e., when subjects did not fixate the targets. In all experimental conditions for trials in which targets were fixated during encoding, there was little correspondence between the marking sequence and the sequence in which the targets were fixated. We conclude that subjects benefit from fixating targets for subsequent target-oriented manual actions when the targets are presented among distractors and when presented sequentially; when distinct targets are presented simultaneously against a blank background, they are efficiently encoded in parallel largely by peripheral vision.     

Age-related changes of the myelinated fibers in the human corticospinal tract: a quantitative analysis

A quantitative analysis was made of the myelinated fibers in the lateral corticospinal tract (LCST) at the levels of the 6th cervical, 7th thoracic and 4th lumbar spinal segments in 20 patients between 19 and 90 years old, and who died of non-neurological diseases. The diameter frequency histograms of myelinated fibers of LCST showed a bimodal pattern with a sharp peak of the small myelinated fibers and broad slope of the large myelinated fibers. The ratio of small fiber to large fiber densities was significantly higher in the 6th cervical (P<0.05) and 4th lumbar segments (P<0.01) than in the 7th thoracic segments. The density of small myelinated fibers was significantly lowered with advancing age (P<0.050.001), while that of large myelinated fibers was not significantly decreased in the aged patients, although it showed a slight age-dependent declining tendency. Age-dependent decline of small fiber density was more prominent in the cervical and lumbar segments. Retraction of the axon-collaterals from large-diameter myelinated fibers, which are abundant in the cervical and lumbar segments, may contribute to the age-related diminution of the small myelinated fibers in the LCST.Part of this work was supported by grants from the Ministry of Welfare and Health of Japan, and a grant from Uehara Memorial Research Foundation