Bruton's tyrosine kinase activity is negatively regulated by Sab, the Btk-SH3 domain-binding protein

Bruton's tyrosine kinase (Btk) is a cytoplasmic tyrosine kinase that is crucial for human and murine B cell development, and its deficiency causes human X-linked agammaglobulinemia and murine X-linked immunodeficiency. In this report, we describe the function of the Btk-binding protein Sab (SH3-domain binding protein that preferentially associates with Btk), which we reported previously as a newly identified Src homology 3 domain-binding protein. Sab was shown to inhibit the auto- and transphosphorylation activity of Btk, which prompted us to propose that Sab functions as a transregulator of Btk. Forced overexpression of Sab in B cells led to the reduction of B cell antigen receptor-induced tyrosine phosphorylation of Btk and significantly reduced both early and late B cell antigen receptor-mediated events, including calcium mobilization, inositol 1, 4,5-trisphosphate production, and apoptotic cell death, where the involvement of Btk activity has been demonstrated previously. Together, these results indicate the negative regulatory role of Sab in the B cell cytoplasmic tyrosine kinase pathway.

Stages III and IV squamous cell carcinoma of the mouth: three-year experience with superselective intraarterial chemotherapy using cisplatin prior to definitive treatment

PURPOSE

This study was designed to assess the 3-year experience with superselective intraarterial chemotherapy prior to definitive treatment for stages III and IV squamous cell carcinomas of the mouth.

METHODS

Twenty-two patients prospectively received superselective intraarterial chemotherapy using relatively low-dose cisplatin via a transfemoral approach. The locations of the tumors were the tongue (n = 12), gingiva (n = 5), buccal mucosa (n = 2), hard palate (n = 1), floor of the mouth (n = 1), and lip (n = 1). After intraarterial chemotherapy, 21 patients underwent surgery (n = 14), radiation therapy (n = 6), or both (n = 1). The survival rate of 25 patients who underwent surgery with/without radiation therapy until 1992 at Kumamoto University Hospital was also evaluated as a historical control. The survival curve was calculated with the Kaplan-Meier method, and the statistical difference between survival curves was determined with the generalized Wilcoxon test.

RESULTS

The overall response rate was 95% [complete response (tumor completely resolved), 24%; partial response (tumor reduction > or = 50%), 71%]. Fifty-two intraarterial infusions were performed without any catheter-related complications. Mild and transient local toxicity such as edema or mucositis of the infused area was relatively common. One patient died of renal failure from cisplatin. After a median follow-up of 20 months (range 2-41 months), the estimated 3-year survival rate for patients who underwent intraarterial chemotherapy plus surgery was 91%. The survival of the patients who underwent intraarterial chemotherapy plus surgery tended to be longer than that of the historical control.

CONCLUSIONS

Early tumor reduction without delay of subsequent treatments can be obtained by intraarterial chemotherapy while minimizing complications and possibly improving survival. Further investigations of long-term survival with larger series need to be performed.

MR imaging of squamous cell carcinoma of the floor of the mouth. Appearance of the sublingual and submandibular glands

PURPOSE

To determine the diagnostic value of MR imaging for tumors of the floor of the mouth and the effects of the tumors on the sublingual and submandibular glands.

MATERIAL AND METHODS

Thirty-seven patients with proven squamous cell carcinoma of the floor of the mouth underwent MR imaging, including unenhanced T1-weighted, T2-weighted, dynamic, and contrast-enhanced T1-weighted images. The appearance of the tumor and the sublingual and submandibular glands was assessed qualitatively and quantitatively.

RESULTS

All tumors demonstrated replacement of the normal signal intensity in the adjacent sublingual gland. Twenty-one patients (57%) had abnormal signal intensity of the submandibular gland without tumor invasion, presumably secondary to submandibular duct obstruction by the tumor. Unenhanced T1-weighted images provided high contrast between tumor and sublingual gland. Tumors limited within the gland were well detected on unenhanced T1-weighted images. Large tumors extending beyond the gland were well delineated on dynamic images, but no better than on T2-weighted images.

CONCLUSION

At MR imaging for tumor of the floor of the mouth, one must carefully evaluate the appearance of the sublingual and submandibular glands. Contrast-enhanced studies are unnecessary when the tumor is limited within the sublingual gland on precontrast MR images.

Quantitative analysis of interleukin 6 (IL-6) in patients with IgA nephropathy after tonsillectomy

The biological response to tonsillectomy was studied in 21 patients suffering from chronic tonsillitis with or without IgA nephropathy (IgAN). Serum and urinary interleukin-6 (IL-6) levels were measured before and after tonsillectomy. Serum IL-6 levels in case of IgAN peaked 3 h after tonsillectomy and more rapidly than control cases. No significant differences were observed between two cases through the time. Urinary IL-6 levels were significantly higher before and at 6 and 48 h after tonsillectomy in IgAN cases. Stimulation of tonsils caused serum IL-6 elevation and changes in urinary IL-6 levels in IgAN cases. Elevation of urinary IL-6 levels after tonsillectomy in patients with IgAN may reflect an increase in the production of IL-6 in the kidneys. Measurement of urinary IL-6 levels after tonsillectomy is useful to elucidate the efficacy of tonsillectomy in IgAN patients.

Dynamic magnetic resonance imaging of head and neck lesions

Dynamic magnetic resonance imaging (MRI) has been used to improve the detection of tumors, to determine the tumor extension, and to make differential diagnosis. Most malignant lesions of the head and neck show early enhancement and early washout of contrast media on dynamic MRI, but the tumor characterization remains unclear. Pharmacokinetic analysis of dynamic MRI can provide information about the permeability of Gd-DTPA in the tumor that may reflect the oxygen concentration of the tumor and the amount of drug delivered to the tumor. This information may be useful in the prediction of radiation and/or chemotherapy response of the tumor.

Tranilast inhibits the proliferation of human coronary smooth muscle cell through the activation of p21waf1

Restenosis after percutaneous transluminal coronary angioplasty (PTCA) occurs due to vascular smooth muscle cell proliferation and migration. Recently, tranilast, an anti-allergic drug, has been used for the prevention of restenosis after PTCA. To determine the molecular mechanism involved, the effect of tranilast on the proliferation of human coronary smooth muscle cells (SMCs) was investigated. Tranilast arrested the proliferation of human coronary SMCs at the G0/G1 phase of the cell cycle. In association with this inhibitory effect, tranilast increased p21waf1 and p53 tumor suppressor factor, and decreased cyclin-dependent kinase 2 (CDK2) activity. These results suggest that tranilast inhibits the proliferation of human coronary SMCs during restenosis after PTCA via an induction of p21waf1 and p53. Tranilast may thus allow us to prevent restenosis after PTCA by interfering with this mechanism.

Involvement of wiskott-aldrich syndrome protein in B-cell cytoplasmic tyrosine kinase pathway

Bruton's tyrosine kinase (Btk) has been shown to play a role in normal B-lymphocyte development. Defective expression of Btk leads to human and murine immunodeficiencies. However, the exact role of Btk in the cytoplasmic signal transduction in B cells is still unclear. This study represents a search for the substrate for Btk in vivo. We identified one of the major phosphoproteins associated with Btk in the preB cell line NALM6 as the Wiskott-Aldrich syndrome protein (WASP), the gene product responsible for Wiskott-Aldrich syndrome, which is another hereditary immunodeficiency with distinct abnormalities in hematopoietic cells. We demonstrated that WASP was transiently tyrosine-phosphorylated after B-cell antigen receptor cross-linking on B cells, suggesting that WASP is located downstream of cytoplasmic tyrosine kinases. An in vivo reconstitution system demonstrated that WASP is physically associated with Btk and can serve as the substrate for Btk. A protein binding assay suggested that the tyrosine-phosphorylation of WASP alters the association between WASP and a cellular protein. Furthermore, identification of the phosphorylation site of WASP in reconstituted cells allowed us to evaluate the catalytic specificity of Btk, the exact nature of which is still unknown.

Interferon-gamma inhibits the myofibroblastic phenotype of rat palatal fibroblasts induced by transforming growth factor-beta1 in vitro

Interferon-gamma (IFN-gamma), a multifunctional cytokine, has been noted as a potential therapeutic agent for various fibrotic disorders, including excessive scar tissue formation. We previously reported that transforming growth factor-beta1 (TGF-beta1) induced the myofibroblastic phenotype in palatal fibroblasts derived from palatal mucosa, and that such effects might have a close link to palatal scar formation. In the present study, we examined the effects of IFN-gamma on TGF-beta1-pretreated palatal fibroblasts for the purpose of clarifying the suppressive potency against myofibroblastic phenotype expression in vitro. IFN-gamma significantly altered the spindle morphology of TGF-beta1-pretreated palatal fibroblasts into the polygonal one that was similar to the non-treated palatal fibroblasts. This change was parallel with a decrease in the expression of alpha-smooth muscle actin protein, a marker for myofibroblast, as determined by immunoblot analysis. Northern blot analysis showed that IFN-gamma inhibited proalpha2(I) collagen mRNA expression that was stimulated by TGF-beta1 pretreatment for 24 h. Furthermore, IFN-gamma decreased the cell contractility enhanced by TGF-beta1 pretreatment for 24 h in a three-dimensional collagen gel culture system. These results suggest that IFN-gamma may have negative effects with regard to controlling the myofibroblastic phenotype induced by TGF-beta1 in palatal fibroblasts.

DNA analysis by microfabricated capillary electrophoresis device

The LIGA (Lithographie Galvanoformung Abformung) process using synchrotron radiation lithography is applied to the microfabrication of capillary array electrophoresis (CAE) device. Laser-induced fluorescence detection system for the CAE device has been constructed by the modification of laser confocal fluorescence microscopy. DNA molecules were detected during migrating in the microchannels filled with polymer separation matrices under electric field to optimize the separation conditions for DNA analysis. Based on this observation, we demonstrated that microfabricated CAE device is realized the fast separation of DNA.

Focal enhanced areas of the liver on computed tomography in a patient with superior vena cava obstruction

We present a patient with superior vena cava (SVC) obstruction in whom two areas of increased hepatic enhancement within the left lobe were seen on abdominal computed tomography (CT). The significance of this case is that abnormal enhancements of the liver on abdominal CT in the regions described should be suggestive of an SVC obstruction on this basis alone.

Simultaneous analysis of genes by capillary electrophoresis with a laser-induced fluorescence detector using a stepwise field strength gradient

A mixture of polymerase chain reaction (PCR) products, 100, 105, 300, 310, 485, and 500 base pair (bp) DNA fragments, was analyzed by capillary electrophoresis equipped with a laser-induced fluorescence detector (CE-LIF) using a stepwise gradient of electric field strength. The optimum condition for the analysis of PCR products was 0.5% methylcellulose and 160 V/cm from 0 to 10 min and 270 V/cm from 10 to 17 min. The length (bp) of DNA could be estimated from the relationship between the relative migration time and bp length. The relative standard deviation (R.S.D.) of DNA size (bp) was less than 3.5% and the difference from the true value was only 2.4 bp.

A case of follicular thyroid cancer with tracheal stenosis responded to external radiation therapy

We report the case of a 70-year-old man with follicular carcinoma of the thyroid who complained of worsening dyspnea and was successfully treated by external radiation therapy. The total dose given was 61 Gy in 28 fractions. This case suggests that external radiation therapy is effective for the management of differentiated thyroid cancer with critical stenosis of the trachea that is inoperable and difficult to treat with radioiodine.

Hyperintense basal ganglia lesions on T1-weighted images in hereditary hemorrhagic telangiectasia with hepatic involvement

We present two patients with hereditary hemorrhagic telangiectasia (HHT) accompanied by multiple hepatic arteriovenous malformations (AVMs) whose cranial MRI demonstrated high signal intensity in the basal ganglia on T1-weighted images. Manganese levels in peripheral blood were very high in both patients. These two cases indicate that there may be a significant relationship between high intensity basal ganglia and multiple hepatic AVMs. While the precise mechanism of the signal alternation in the basal ganglia is unproven, high blood levels of manganese in these patients suggest that abnormal intensity in the basal ganglia may be due to deposition of manganese.

Analysis of variable number of tandem repeats of human genome D1S80 locus using capillary electrophoresis with laser-induced fluorescence detector

The conventional method of identifying individuals by DNA in the field of forensic medicine is slab gel electrophoresis, which is time-consuming, labor-intensive, and nonquantitative. Accordingly, the use of capillary electrophoresis with a laser-induced fluorescence detector (CE-LIF), human genome D1S80 locus, a DNA marker which has a variable number of tandem repeats (VNTR) on chromosome 1, was examined to improve DNA analysis for identification. Using an internal standard, fragment size of VNTR was accurately and rapidly determined.

[Characteristics and progress of treatment for gastric cancers detected by mass screening]

We devised an X-ray examination to detect early gastric cancer, especially small gastric cancer, during the period between 1996 and 1997. As a result, the rate of gastric cancer detection by mass screening was 0.50%; and the rate of early gastric cancer detection was 79%. 1. Characteristics of gastric cancer detected by mass screening: Characteristics of gastric cancer were depressive-type undifferentiated cancer less than 4.0 cm diameter in work-place screening and depressive-type differentiated cancer less than 4.0 cm in area screening; 2. gastric cancer less than 2.0 cm in diameter was 75 (68%) of the 110 cases (total detected gastric cancer). 2) We have to consider that gastric cancer differs by sex and age. 3) EMR accounted for 39 (35%) of the 110 cases in treatment. This method resulted in a higher gastric cancer detection rate and served to maintain QOL.

Osseous primitive neuroectodermal tumor--a case report

PNET and Ewing sarcoma are pathologically distinct entities with very similar clinical and radiological characteristics. Immunohistochemical studies are needed to distinguish PNET from Ewing sarcoma, with the former being characterized by neural differentiation. We present the case of a 17-year-old man with immunohistochemically confirmed PNET in the cervical vertebrae.

Optimal image resolution for digital storage of radiotherapy-planning images

PURPOSE

To evaluate the quality of digitized radiation-planning images at different resolution and to determine the optimal resolution for digital storage.

METHODS AND MATERIALS

Twenty-five planning films were scanned and digitized using a film scanner at a resolution of 72 dots per inch (dpi) with 8-bit depth. The resolution of scanned images was reduced to 48, 36, 24, and 18 dpi using computer software. Image qualities of these five images (72, 48, 36, 24, and 18 dpi) were evaluated and given scores (4 = excellent; 3 = good; 2 = fair; and 1 = poor) by three radiation oncologists. An image data compression algorithm by the Joint Photographic Experts Group (JPEG) (not reversible and some information will be lost) was also evaluated.

RESULTS

The scores of digitized images with 72, 48, 36, 24, and 17 dpi resolution were 3.8 +/- 0.3, 3.5 +/- 0.3, 3.3 +/- 0.5, 2.7 +/- 0.5, and 1.6 +/- 0.3, respectively. The quality of 36-dpi images were definitely worse compared to 72-dpi images, but were good enough as planning films. Digitized planning images with 72- and 36-dpi resolution requires about 800 and 200 KBytes, respectively. The JPEG compression algorithm produces little degradation in 36-dpi images at compression ratios of 5:1.

CONCLUSION

The quality of digitized images with 36-dpi resolution was good enough as radiation-planning images and required 200 KBytes/image.

The 21-kDa polypeptide (VAP21) in the rabies virion is a CD99-related host cell protein

In our monoclonal antibody (MAb) stocks prepared against the BHK-21 cell antigens, two (#11875 and 28276) recognized a 21-kDa polypeptide (referred to as VAP21) which is efficiently incorporated into the rabies virion. By using these MAbs, we isolated the cDNA clones that encoded a polypeptide of 144 amino acids from our BHK-21 cell cDNA library. Based on the following evidence, the cDNA was assumed to encode a full-length sequence of VAP21 antigen: i) expression of the cDNA in animal cells resulted in the production of a polypeptide recognized by the two MAbs, and its electrophoretic mobility was the same as that of authentic VAP21 antigen; and ii) immunization with the products from the cDNA-transformed E. coli cells raised specific antibodies in rabbits that recognized a 21-kDa polypeptide in the virion. From the deduced amino acid sequence, it is suggested that the VAP21 antigen has a molecular structure of type-I transmembrane protein containing characteristic proline-rich and glycine-rich regions in its ectodomain. Homology searches resulted in finding homologous sequences (totally about 40% homology) in the human MIC2 gene product (CD99; 32-kDa) of T lymphocytes. These results suggest that the VAP21 antigen in the rabies virion is a cellular CD99-related transmembrane protein.

[Basic studies on IL-2 gene therapy for head and neck carcinoma]

Basic studies on transduction of the interleukin-2 (IL-2) gene into tumor cells were carried out in order to develop a new immunotherapy for head and neck carcinomas. We transduced the IL-2 gene into KB cells using defective herpes simplex viral (HSV) amplicon vector as the gene transfer vehicle. A high level of IL-2 was produced by IL-2 gene transduced KB cells (KB/IL-2). Human peripheral blood mononuclear cells (PBMC) cultured in medium containing the culture supernatant of KB/IL-2 cells showed stronger cytotoxic activity against KB cells than the control. In in vivo studies, high levels of IL-2 and interferon-gamma (IFN-gamma) were detected in the serum of nude mice transplanted with KB/IL-2 cells. The spleen cells of KB/IL-2 cell-transplanted nude mice exhibited high cytotoxic activity. Three of 5 nude mice transplanted with KB/IL-2 cells were completely cured of their tumor, and all 3 mice survived for over 120 days. All 5 nude mice transplanted with KB/lacZ cells, and all 5 nude mice transplanted with KB cells died within 120 days as a result of tumor progression. In conclusion, transduction of IL-2 gene tumor cells was corroborated by the high level of IL-2 produced by KB/IL-2 cells. The mechanisms of tumor rejection on KB/IL-2 transplanted nude mice were thought to be that effector cells stimulated by IL-2 derived from transplanted KB/IL-2 cells killed tumor cells, and IFN-gamma produced by activated NK cells showed a synergistic effect on tumor cells-killing.

Cyclin D1 expression as a prognostic factor in advanced hypopharyngeal carcinoma

Hypopharyngeal carcinoma (HPC) has a poor prognosis. We investigated the expression of cyclin D1 in 34 advanced HPCs, and the value of cyclin D1 expression was evaluated as a predictive marker in terms of the prognosis of HPC, compared with other clinical factors. Using immunohistochemical staining, 20 of 34 patients showed positive immunoreactivity for cyclin D1. The statistical trend of the survival rate was lower in the cyclin D1-positive patients than in the cyclin D-negative ones (p = 0.0805). The predictive factors for the survival rate were effectiveness of neo-adjuvant chemotherapy (F = 8.698) (p = 0.0066), cyclin D1 expression (F = 6.244) (p = 0.0191) and N classification (F = 5.037) (p = 0.0335). The cyclin D1-positive patients had approximately four-fold higher mortality than the cyclin D1-negative ones. These data indicate that the expression of cyclin D1, in advanced patients with hypopharyngeal carcinoma is a useful marker for prognosis.