[Suppression of spontaneous AC potentials in guinea pig cochlea by external tones]

Spontaneous electrical oscillations (AC potentials) were observed in the cochlea of three guinea pigs without any exposure to noise or drugs. The AC potentials disappeared completely within one minute after the cessation of artificial ventilation, and were suppressed by presenting external tones to the ear. As the frequency of the external tone was displaced toward that of the spontaneous oscillation, the signals were increasingly suppressed. Exposure to intense tone produced residual suppression of the AC potentials for several minutes. The time course of recovery from the suppression appeared to be similar to that in the noise induced temporary threshold shift measured psychoacoustically. From these results, it was concluded that the spontaneous AC potentials in the guinea pig cochlea were generated by the active mechanical vibration system at the area on the basilar membrane where the characteristic frequency corresponded to that of the AC potentials.

Prognostic significance of Ki-67 labeling indices obtained using MIB-1 monoclonal antibody in patients with supratentorial astrocytomas

BACKGROUND

Identification of the prognosis of patients with gliomas is important for selecting and evaluating the effectiveness of treatment. The aim of this study was to evaluate the Ki-67 labeling index (LI) using the newly generated MIB-1 monoclonal antibody (MoAb) as a prognostic indicator for patients with astrocytomas.

METHODS

Ki-67 immunohistochemistry was performed on paraffin sections to estimate the growth potential of 72 supratentorial astrocytomas using the MIB-1 MoAb after hydrated autoclaving treatment. Multivariate analysis using the Cox proportional hazard stepwise model was used to evaluate the influence of Ki-67 LI, as well as other prognostic factors, on the duration of survival of patients with supratentorial astrocytomas.

RESULTS

The mean Ki-67 LI was 3.8% (+/- 2.7%; standard deviation [SD]) in Grade 2 gliomas (n = 19), 18.4% (+/- 9.7% SD) in Grade 3 gliomas (n = 25), and 31.6% (+/- 12.9% SD) in Grade 4 gliomas (n = 28). Multivariate survival analysis showed that histologic grade, Ki-67 LI, and Karnofsky performance status (KPS) score before and after treatment were independent, statistically significant prognostic factors for patients with all grades of astrocytomas. In high grade lesions, Ki-67 LI, tumor location (superficial vs. deep), and KPS score after treatment were significant prognostic variables, whereas histologic grade did not meet the significance level for entry into the stepwise model.

CONCLUSIONS

These results indicate that the Ki-67 LI obtained using MIB-1 MoAb is an important and practical tool for estimating biologic behavior of gliomas, as well as for predicting survival.

In vivo antitumor effect of cytotoxic T lymphocytes engineered to produce interferon-gamma by adenovirus-mediated genetic transduction

Immunotherapy with adoptive transfer of genetically-modified cytotoxic T lymphocytes (CTL) is a promising approach for cancer gene therapy. We developed an adoptive therapy model with murine tumor-specific CTL, to which very efficient (up to 100%) gene introduction was achieved by using recombinant adenoviral vectors. Through a comparative study on the antitumor effects of CTL genetically modified with cytokine genes, transduction with interferon-gamma gene resulted in a prominent increase in therapeutic efficacy of CTL in both metastatic and subcutaneous tumor models. Further additive effect was obtained by the adoptive cellular therapy in combination with vaccination of cytokine gene-modified tumor cells. Our findings provide a hopeful strategy of adoptive immunotherapy for human cancers.

Immunohistochemical detection of Ki-67 in replicative smooth muscle cells of rabbit carotid arteries after balloon denudation

BACKGROUND AND PURPOSE

Ki-67 immunohistochemistry has been shown to be useful for paraffin sections from human species after wet heating. We applied Ki-67 immunohistochemistry to rabbit arteries after balloon denudation and compared the results with proliferating cell nuclear antigen (PCNA) immunohistochemistry.

METHODS

Monoclonal antibodies MIB-1 for Ki-67 and PC-10 for PCNA were used to detect replicative smooth muscle cells in rabbit carotid arteries during a period of 4 weeks after balloon endothelial denudation.

RESULTS

We demonstrated clear immunoreactivities for Ki-67 in paraffin sections of rabbit arteries after hydrated autoclaving. Ki-67-positive smooth muscle cells appeared throughout the thickened intima 1 week after endothelial denudation. At 2 weeks, Ki-67-positive cells were confined to the surface layer of the intima. PCNA-positive cells appeared in almost the same location by 2 weeks after endothelial denudation but were significantly greater in number than Ki-67-positive cells. PCNA-positive cells remained in the surface layer of the intima 4 weeks after endothelial denudation, while Ki-67-positive cells had almost disappeared from the intima.

CONCLUSIONS

Our results indicate that Ki-67 immunohistochemistry using MIB-1 monoclonal antibody provides a powerful tool, even in rabbit species, for the detection of replicative smooth muscle cells during the repair of arterial injury and that it detects replicative cells more accurately than PCNA immunohistochemistry.

Serum concentrations of IL-5, GM-CSF, and IL-3 and the production by lymphocytes in various eosinophilia

The concentrations of interleukin-5 (IL-5), granulocyte-macrophage colony-stimulating factor GM-CSF, and interleukin-3 (IL-3) in serum and in IL-2-stimulated lymphocyte culture medium (L-IL2-CM) prepared from patients with reactive eosinophilia were measured by enzyme-linked immunosorbent assay (ELISA). Serum IL-5 levels were increased in 16 out of 42 cases. GM-CSF and IL-3 were below the detectable levels in all sera examined. The concentrations of IL-5 and GM-CSF in L-IL2-CM were increased in 10 out of 29 patients. IL-3 was below the detectable levels in all L-IL2-CM.

Immunohistochemical detection of progesterone receptors and the correlation with Ki-67 labeling indices in paraffin-embedded sections of meningiomas

Female sex steroids may play a role in the proliferation of meningiomas. We investigated the progesterone receptor (PgR) immunoreactivities and the Ki-67 labeling indices in the formalin-fixed, paraffin-embedded sections of meningiomas from 39 patients. After autoclave pretreatment of the sections (which were immersed in a citrate buffer), the sections were incubated with the monoclonal antibody for the PgR and the MIB-1 monoclonal antibody for the Ki-67 antigen. In the meningiomas studied, the immunoreactivity for the PgR was moderately to strongly positive in 51%, weakly positive in 21%, and negative in 28%. The nuclear staining for the PgR was clear, and no tumors were positive for the estrogen receptor. The Ki-67 labeling indices of the PgR-positive meningiomas (mean +/- standard deviation, 2.35 +/- 2.12%) were significantly lower than those of the PgR-negative meningiomas (6.53 +/- 4.83%) (P < 0.05). Two meningiomas that had recurred more than once showed high Ki-67 labeling indices and negative immunostaining for the PgR. These findings indicate that the PgR status may be closely related to the growth potentials of the meningiomas. Our results confirm that the immunodetection of the PgR and the Ki-67 antigen on the paraffin sections of meningiomas provides a practical tool for estimating the biological behavior of the meningiomas.

Antitumor effect induced by granulocyte/macrophage-colony-stimulating factor gene-modified tumor vaccination: comparison of adenovirus- and retrovirus-mediated genetic transduction

Irradiated tumor cells genetically modified to secrete granulocyte/macrophage-colony-stimulating factor (GM-CSF tumor vaccine) are potent stimulators of systemic antitumor immunity. For the preparation of a GM-CSF gene-modified tumor vaccine, it is important to achieve efficient genetic transduction of tumor cells, leading to an appropriate expression of the induced gene. In this report, with a view to developing a protocol for an effective cancer vaccination therapy, we examined the vaccination efficacies of tumor cells secreting GM-CSF by either adenovirus- or retrovirus-mediated genetic transduction. By using an adenoviral vector, Adex1CAmGMCSF, a highly efficient gene delivery and a high-level expression of the GM-CSF gene were achieved. Unexpectedly, animal vaccination studies showed that the GM-CSF tumor vaccine transduced with the Adex1CAmGMCSF recombinant adenovirus (adenoviral GM-CSF tumor vaccine) was less efficacious than that transduced with the MFGmGMCSF recombinant retrovirus (retroviral GM-CSF tumor vaccine). The GM-CSF serum concentration attained by the adenoviral GM-CSF tumor vaccine was much higher than that obtained by the retroviral GM-CSF tumor vaccine. Our findings indicate that an optimal level of GM-CSF production is important for the tumor vaccine to elicit an adequate response in the host antitumor immunity.

Endogenous bone-resorbing factors in estrogen deficiency: cooperative effects of IL-1 and IL-6

Estrogen deficiency causes a marked bone loss by stimulating osteoclastic bone resorption. To explore the endogenous bone-resorbing factors involved in estrogen deficiency, we examined the bone-resorbing activity present in the supernatant fraction of mouse bone marrow collected from ovariectomized (OVX) mice. Adding bone marrow supernatants at 20-80% to organ cultures of mouse long bones dose-dependently stimulated bone resorption. The endogenous bone-resorbing activity present in bone marrow supernatants from OVX mice was much higher than that from sham-operated mice 2-4 weeks after surgery, and it was significantly diminished by indomethacin in vitro. Anti-IL-1 alpha antibody completely neutralized the bone-resorbing activity present in bone marrow supernatants from OVX mice. Antibodies against IL-1 beta, IL-6, and IL-6 receptors also neutralized it, but partially. The concentration of IL-1 alpha measured by ELISA was much higher in bone marrow supernatants than in sera, but it was not appreciably changed before or after OVX. The concentration of IL-1 beta in bone marrow supernatants from OVX mice was less than the detection limit. OVX stimulated IL-1 activity in bone marrow supernatants measured by means of the proliferation of thymocytes. However, the level of IL-1 alpha present in bone marrow supernatants from OVX mice was insufficient to stimulate bone resorption. Compared with the serum concentration, bone marrow supernatants contained a much higher level of IL-6 as well, and it was further increased by OVX. However, IL-6 alone present in bone marrow supernatants from OVX mice again did not stimulate bone resorption.(ABSTRACT TRUNCATED AT 250 WORDS)

Kinetics of 125I-PDGF binding and down-regulation of PDGF receptor in human arterial smooth muscle cell strains during cellular senescence in vitro

Platelet-derived growth factor (PDGF) is one of the major mitogens in serum to stimulate replication of human smooth muscle cells (SMCs) in culture. Previous studies using human fibroblasts failed to demonstrate changes in the receptor systems for growth factors during cellular senescence. We investigated the kinetics of 125I-PDGF(-BB) binding and down-regulation of the PDGF receptor in three human arterial SMC strains during cellular aging. The number of specific 125I-PDGF binding sites per cell increased slightly at a population doubling level (PDL) of 60%-80% of life span and then decreased at the PDL above 90%. The number of receptors per cell-surface area decreased with increasing in vitro age. The apparent Kd for the 125I-PDGF binding decreased with in vitro senescence. The internalization and degradation of 125I-PDGF per receptor were significantly reduced in senescent SMCs and the amount of 125I-PDGF that escaped degradation and was recycled back to the cell surface was significantly greater in senescent SMCs than young cells. Furthermore, down-regulation of the PDGF receptor was significantly greater in senescent SMCs than young cells. Immunoblot studies demonstrated that changes in beta-subunit of the PDGF receptor accounted for those in the studies using 125I-PDGF and that tyrosine phosphorylation of the PDGF receptor was significantly greater in young SMCs than aged cells. Our results suggest that age-related changes in the receptor systems for PDGF may be important contributors to the failure of DNA synthesis in senescent SMCs.

Cytokine-gene-modified tumor vaccination intensified by a streptococcal preparation OK-432

Vaccinations with tumor cells engineered to express certain cytokines have been demonstrated to induce potent and specific antitumor immunity. In our previous report, we carried out a comparative study on the ability of cytokine-gene-modified tumor vaccines to induce host immune responses, and found that irradiated tumor cells, genetically modified to secrete granulocyte/macrophage-colony-stimulating factor (GM-CSF tumor vaccine), were the most potent stimulators of systemic antitumor immunity. In this report, using the experimental tumor models in which the GM-CSF tumor vaccine was less effective in immunopotentiation, we found that the combined use of a biological response modifier (BRM) OK-432 remarkably enhanced the antitumor activity induced by the GM-CSF tumor vaccine. These data indicate the possible role of a BRM such as OK-432 to intensify further the specific tumor vaccination therapy.

Identification of integrins involved in cell adhesion to native and denatured type I collagens and the phenotypic transition of rabbit arterial smooth muscle cells

Rabbit smooth muscle cells (SMC) in primary culture attached to and started proliferating on native and heat-denatured type I collagens, although the amount of cell attachment to denatured collagen was significantly lower. The cells adhered poorly and were unable to grow on commercial gelatin. In contrast, synthetic SMC in secondary culture could adhere to gelatin and grew as well on gelatin as on native type I collagen. The SMC in the contractile state adhered to native type I collagen through the alpha 1 beta 1 and alpha 3 beta 1 integrins. The cells in the intermediate phenotype also adhered to the substrate through the alpha 1 beta 1 and alpha 3 beta 1 integrins, but the relative amount of alpha 3 integrin decreased. The initial adhesion of cells in secondary culture to native type I collagen was mediated only by the alpha 1 beta 1 integrin. The cell-binding sequences did not contain DGEA (Asp-Gly-Glu-Ala) or RGD (Arg-Gly-Asp). In contrast, cell adhesion to heat-denatured type I collagen was mediated only by the alpha 1 beta 1 integrin in the contractile state and by the alpha 1 beta 1, alpha 2 beta 1, and alpha 3 beta 1 integrins in the synthetic state. In heat-denatured type I collagen, the sequences DGEA and RGD served as a recognition site for the alpha 2 beta 1 and alpha 3 beta 1 integrins. Our results suggest that rabbit SMC can recognize the native and denatured type I collagens through interactions with the triple helix-binding receptors and alpha chain-binding receptors and that the expression pattern of integrins changes in conjunction with the phenotypic properties of vascular SMC.

Enhancement of retrovirus-mediated gene transduction efficiency by transient overexpression of the amphotropic receptor, GLVR-2

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Changes in elastin-binding proteins during the phenotypic transition of rabbit arterial smooth muscle cells in primary culture

Elastin, a major constituent of the media, may play an important role in the attachment, migration, and phenotypic properties of vascular smooth muscle cells (SMC). We examined binding proteins and binding sites on elastin in rabbit arterial SMC in primary culture. Freshly isolated cells on alpha-elastin underwent phenotypic transition from a contractile to a synthetic state after 5 days of culture under serum-deficient conditions (1% FBS) and began to proliferate after 6 days of culture (48 h later than on plastic dishes). SMC in the contractile state expressed two binding proteins (130 and 36 kDa), while the 130-kDa band was undetectable in cells in the synthetic state. The adhesion of freshly isolated cells and cells in the synthetic state to alpha-elastin was significantly inhibited by a monoclonal anti-elastin receptor antibody (BCZ-67). The synthetic peptide VGVAPG (Val-Gly-Val-Ala-Pro-Gly), which contains the recognition sequence for the elastin receptor, inhibited the adhesion of freshly isolated cells to alpha-elastin at 0.01-1 mM, but showed no inhibitory activity on the adhesion of cells in the synthetic state at 0.01 mM. These findings suggest that alpha-elastin suppresses the phenotypic transition of rabbit arterial SMC by interacting with the high-molecular-size (130 kDa) binding protein for a cell-binding sequence VGVAPG, while cells in the synthetic state can recognize alpha-elastin through interactions with the low-molecular-size (36 kDa) binding protein for the sequence VGVAPG.

[Effect of acid aspiration on right lymph duct lymph flow and prostaglandin metabolites in dogs]

Aspiration of acid gastric contents into the airways is a major cause of pulmonary injury. The author investigated the effects of intratracheal instillation of hydrochloric acid in the anesthetized dogs on pulmonary hemodynamics, pulmonary lymph flow and protein content, and stable metabolites of prostaglandin F2 alpha (PGF2 alpha), prostacyclin (PGI2) and thromboxane A2 (TXA2). The author measured the concentrations of 15-keto-13, 14-H2-PGF2 alpha, 6-keto-PGF1 alpha and TXB2 in blood and pulmonary (right duct) lymph by specific radioimmunoassay. After intratracheal instillation of 0.1 N HCL, 3 ml.kg-1, the right duct lymph flow increased significantly from 1.3 to 4.5 ml.h-1, and pulmonary lymph-to-plasma protein ratio increased significantly from 0.63 to 0.70. There was no significant change in hemodynamics after acid instillation. There was no significant change in arterial or mixed-venous blood levels of any of the three metabolites. After acid instillation, the right duct lymph concentrations increased 2-fold for PGI2 metabolite, 3-fold for TXB2, and 7-fold for PGF2 alpha metabolite. The flow of metabolites (concentration x flow) increased 13-fold for 6-keto-PGF1 alpha, 14-fold for TXB2, and 40-fold for PGF1 alpha metabolite. The author concludes that intratracheal instillation of hydrochloric acid in anesthetized dogs: 1) increases pulmonary microvascular permeability, and 2) stimulates the pulmonary generation of PGF2 alpha, prostacyclin and thromboxane, and that 3) the analysis of pulmonary lymph flow and its constituents is a useful means for the study of lung injuries.

Human leukocyte antigen in patients with moyamoya disease

BACKGROUND AND PURPOSE

Progressive stenosis or occlusion of bilateral internal carotid arteries by fibrocellular intimal thickening results in cerebral ischemia in moyamoya disease. In an attempt to elucidate the still-unknown etiologic factors in moyamoya disease, we assessed human leukocyte antigens in patients with this disease.

METHODS

We investigated 32 unrelated Japanese patients with moyamoya disease for typing of human leukocyte antigen A, B, C, and DR/DQ and compared the results with those from 178 unrelated control subjects.

RESULTS

We found a significant association of human leukocyte antigen B51 with moyamoya disease (corrected P < .05, chi 2 test). Although no significant associations were observed in DR/DQ typing, the frequency of the B51-DR4 combination was significantly higher in moyamoya patients than in control subjects (P < .002, Fisher's exact test).

CONCLUSIONS

These findings suggest that there may be a genetic predisposition for moyamoya disease and that host factors may play a role in the development of intimal thickening in early childhood.

[Complete remission achieved by low-dose Ara-C, aclarubicin and rhG-CSF (CAG) therapy in acute non-lymphocytic leukemia with monosomy 7 occurring after severe aplastic anemia]

We report a case of acute myelogenous leukemia (AML), which developed from severe aplastic anemia (SAA) and was successfully treated by low-dose Ara-C and aclarubicin with concomitant use of G-CSF (CAG therapy). A 37-year-old male was admitted for scrutiny of pancytopenia and diagnosed as SAA because of hypocellular bone marrow without abnormal or dysplastic cells. Although hematopoiesis recovered with steroid pulse therapy followed by administration of anabolic steroids, 29 months after initial onset of SAA, he presented as AML (FAB-M6), as his bone marrow Contained 21.6% leukemic myeloblasts and 56% of erythroblasts. Chromosome study revealed 45, XY, -7 in 14 of 20 cells analyzed. Complete remission was achieved by administration of low-dose Ara-C (20 mg/m2 for 7 days) and aclarubicin (14 mg/m2 for 4 days) along with G-CSF (200 micrograms/m2 for 7 days), without any severe complications. In the previous reports in Japan since 1982, 7 out of 8 cases with AML developing from SAA died within a year. Our results indicate that CAG therapy is useful for treatment for this subset of AML with poor prognosis.

Effects of acoustic overstimulation on 2f1-f2 distortion product in the cochlear microphonics

The cochlear microphonics (CM) in response to two-tone stimuli as well as the threshold of compound action potential (CAP) were measured before and after exposure to 4 kHz pure tone at 100 dB SPL for 10 min. Although the loss of CM output at the primary frequencies was limited to around 2 dB, the 2f1-f2 distortion products in the CM (CM-DPs) were markedly reduced immediately after the exposure, especially at low primary levels (i.e. less than 65 dB). The low level CM-DPs recovered gradually near the initial level within 7 days from the exposure. The elevation of CAP threshold closely paralleled with the reduction of CM-DPs in not only the acute phase but also in the recovery phase from the exposure. These results show that the active transduction process in the cochlea was affected by acoustic overstimulation. This impairment of the active transduction was postulated to play an important role in developing the noise induced temporary threshold shift.

Cell adhesion molecules acting between C6 glioma and endothelial cells

The interactions between tumor cells and endothelium play a key role in the process of tumor growth, local invasion, and distant metastasis. In the present study, we examined the adhesion of C6 glioma cells to bovine endothelial cell (EC) monolayers and defined the cell adhesion molecules acting between these cells. Pretreatment of the EC monolayer with cytokines, tumor necrosis factor (TNF)-alpha, interleukin (IL)-1 beta, and interferon (INF)-gamma, significantly increased the adhesion of C6 glioma cells to the EC monolayer. The effect lasted more than 24 hours and was protein-synthesis dependent. The adhesion of C6 glioma cells to TNF-activated ECs was blocked by the monoclonal antibody to the intercellular adhesion molecule-1 (ICAM-1) or beta 2 integrin, whereas that of melanoma cells was not. These findings provide evidence that ICAM-1 and beta 2 integrin function as inducible cell surface molecules that can support the adhesion of C6 glioma cells to ECs, and may contribute to the characteristic growth of glial tumors in vivo.

Serum concentrations of interleukin-5 and the production of lymphocytes in reactive eosinophilia

The concentrations of interleukin-5 (IL-5) in serum and in IL-2-stimulated lymphocyte culture medium (L-IL2-CM) prepared from patients with reactive eosinophilia were measured by enzyme-linked immunosorbent assay. The serum IL-5 concentration was increased in 16 of 34 cases. The concentrations of IL-5 in L-IL2-CM were increased in 8 of 21 patients.

Adoptive immunotherapy with murine tumor-specific T lymphocytes engineered to secrete interleukin 2

Adoptive immunogene therapy of cancer is not widely studied, although it has been proposed as a promising strategy for cancer gene therapy. One of the major obstacles to this approach is the difficulty in introducing cytokine genes efficiently into T lymphocytes. In this report, we developed an adoptive immunotherapy model with murine tumor-specific cytotoxic T lymphocytes. By using an adenoviral vector, we achieved up to 100% gene transduction of murine T lymphocytes. Treatment of mice with the cytotoxic T lymphocytes genetically modified to produce interleukin 2 resulted in reduction of tumor metastasis and longer survival from intracerebral tumor death, providing a hopeful strategy for treatments of human cancers.