Detection of human coronavirus RNA in surgical smoke generated by surgical devices

BACKGROUND

Gaseous by-products generated by surgical devices - collectively referred to as 'surgical smoke' - present the hazard of transmitting infective viruses from patients to surgical teams. However, insufficient evidence exists to evaluate and mitigate the risks of SARS-CoV-2 transmission via surgical smoke.

AIM

To demonstrate the existence and infectivity of human coronavirus RNA in surgical smoke using a model experiment and to evaluate the possibility of lowering transmission risk by filtration through a surgical mask.

METHODS

Pelleted HeLa-ACE2-TMPRSS2 cells infected with human coronavirus were incised by electric scalpel and ultrasonic scalpel, separately. A vacuum system was used to obtain surgical smoke in the form of hydrosol. Reverse transcription-quantitative polymerase chain reaction was used to analyse samples for the presence of viral RNA, and infectivity was determined through plaque assay. Furthermore, a surgical mask was placed centrally in the vacuum line to evaluate its ability to filter viral RNA present in the surgical smoke.

FINDINGS

In this model, 1/10⁶ to 1/10⁵ of the viral RNA contained in the incision target was detected in the collected surgical smoke. The virus present in the smoke was unable to induce plaque formation in cultured cells. In addition, filtration of surgical smoke through a surgical mask effectively reduced the amount of viral RNA by at least 99.80%.

CONCLUSION

This study demonstrated that surgical smoke may carry human coronavirus, though viral infectivity was considerably reduced. In clinical settings, surgical mask filtration should provide sufficient additional protection against potential coronavirus, including SARS-CoV-2, infection facilitated by surgical smoke.

High and pointed type of femoral localized reaction frequently extends to complete and incomplete atypical femoral fracture in patients with autoimmune diseases on long-term glucocorticoids and bisphosphonates

Once a localized reaction (beaking) was detected, discontinuation of bisphosphonates (BPs) and switching to vitamin D supplementation or teriparatide therapy effectively improved its shape. When the localized reaction was high, of the pointed type, and/or accompanied by prodromal pain, the risks of complete and incomplete atypical femoral fracture increased and consideration of prophylactic fixation for such patients was required.

INTRODUCTION

Femoral localized reaction (localized periosteal thickening of the lateral cortex, beaking) is reported to precede atypical femoral fractures (AFFs) and to develop in 8-10% of patients with autoimmune diseases taking BPs and glucocorticoids. The aims of the present study were to retrospectively investigate the shapes of localized reaction to consider how to manage the condition.

METHODS

Twenty femora of 12 patients with autoimmune diseases who were on BPs and glucocorticoids exhibited femoral localized reaction. The heights of localized reaction were measured and the shapes classified as pointed, arched, and other. Localized reaction changes were divided into three categories: deterioration, no change, and improvement. A severe form of localized reaction was defined; this was associated with prodromal pain, de novo complete AFF, or incomplete AFF with a fracture line at the localized reaction.

RESULTS

The mean height of localized reaction was 2.3 ± 0.8 mm (range, 1.0-3.7 mm) and the pointed type was 35%. Localized reaction was significantly higher (3.3 ± 0.8 vs. 2.1 ± 0.7 mm; p = 0.003) and the pointed type more common (78 vs. 27%; p = 0.035) in those with the severe form of localized reaction. Seven patients with localized reactions discontinued BPs just after localized reaction was detected, but five continued on BPs for 2 years. Localized reaction deterioration was more common in patients who continued than discontinued BPs (100 vs. 29%; p = 0.027). After 2 years, all patients had discontinued BPs and localized reaction did not deteriorate further in any patient.

CONCLUSIONS

Once a localized reaction was detected, discontinuation of BPs and switching to vitamin D supplementation or teriparatide therapy effectively improved it. When the localized reaction was high, of the pointed type, and/or accompanied by prodromal pain, the risks of complete and incomplete AFF increased and consideration of prophylactic fixation for such patients was required.

The cumulative incidence of and risk factors for latent beaking in patients with autoimmune diseases taking long-term glucocorticoids and bisphosphonates

SUMMARY

The incidence of beaking, which has been reported to precede atypical femoral fracture, was high and increased over 2 years in patients with autoimmune diseases who were taking bisphosphonates and glucocorticoids. Regular femoral X-rays are strongly recommended to screen for beaking, and bisphosphonate drug holidays should be considered.

INTRODUCTION

Atypical femoral fractures (AFFs) have been recently recognized as complications associated with bisphosphonate (BP) use. AFFs are considered to be stress fractures; localized periosteal thickening of the lateral cortex is often present at the fracture site; this thickening is termed "beaking." Beaking has been reported to precede AFF. The aims of the present study were to evaluate the incidence of latent beaking in patients with autoimmune diseases taking BPs and glucocorticoids and to identify risk factors for beaking.

METHODS

A total of 125 patients with autoimmune diseases who were taking BPs and glucocorticoids was included; 116 patients underwent X-rays and analysis of serum and urine bone metabolic markers annually for 2 years. Mean patient age was 54.5 years; there were 105 (90.5%) females and the mean duration of disease was 13.2 years. Focal lateral cortical thickening in femoral X-rays was defined as beaking.

RESULTS

Beaking was detected in 15 femora of 10 patients (8.0%) at the time of recruitment. Over the 2-year observation period, the incidence of beaking increased to 21 femora of 12 patients (10.3%), and a complete AFF at the location of beaking occurred in one patient. Beaking was associated with a longer duration of BP treatment (6.1 ± 1.0 years vs. 5.0 ± 2.9 years, p = 0.01). Age 40-60 years, BP therapy ≥4 years, and diabetes mellitus were significantly associated with beaking.

CONCLUSIONS

The incidence of beaking was high, and increased over 2 years, in patients with autoimmune diseases who were taking BPs and glucocorticoids. Regular femoral X-rays are strongly recommended to screen for beaking. Long-term BP/glucocorticoid use was a risk factor for beaking in patients with autoimmune diseases; BP drug holidays should be considered.

Oral administration of an HSP90 inhibitor, 17-DMAG, intervenes tumor-cell infiltration into multiple organs and improves survival period for ATL model mice

In the peripheral blood leukocytes (PBLs) from the carriers of the human T-lymphotropic virus type-1 (HTLV-1) or the patients with adult T-cell leukemia (ATL), nuclear factor kappaB (NF-κB)-mediated antiapoptotic signals are constitutively activated primarily by the HTLV-1-encoded oncoprotein Tax. Tax interacts with the I κB kinase regulatory subunit NEMO (NF-κB essential modulator) to activate NF-κB, and this interaction is maintained in part by a molecular chaperone, heat-shock protein 90 (HSP90), and its co-chaperone cell division cycle 37 (CDC37). The antibiotic geldanamycin (GA) inhibits HSP90's ATP binding for its proper interaction with client proteins. Administration of a novel water-soluble and less toxic GA derivative, 17-dimethylaminoethylamino-17-demethoxygeldanamycin hydrochloride (17-DMAG), to Tax-expressing ATL-transformed cell lines, C8166 and MT4, induced significant degradation of Tax. 17-DMAG also facilitated growth arrest and cellular apoptosis to C8166 and MT4 and other ATL cell lines, although this treatment has no apparent effects on normal PBLs. 17-DMAG also downregulated Tax-mediated intracellular signals including the activation of NF-κB, activator protein 1 or HTLV-1 long terminal repeat in Tax-transfected HEK293 cells. Oral administration of 17-DMAG to ATL model mice xenografted with lymphomatous transgenic Lck-Tax (Lck proximal promoter-driven Tax transgene) cells or HTLV-1-producing tumor cells dramatically attenuated aggressive infiltration into multiple organs, inhibited de novo viral production and improved survival period. These observations identified 17-DMAG as a promising candidate for the prevention of ATL progression.

Negative effect of transforming growth factor-beta-1 on intestinal anastomotic tissue regeneration

To examine the involvement of transforming growth factor-beta(1 )(TGF-beta(1)) in intestinal anastomotic repair, we administered a TGF-beta(1)-neutralizing antibody to rats after operation, and then examined its influence on the healing process and interaction with other peptide growth factors. Thirty male Sprague-Dawley rats were subjected to primary anastomosis after transection of the small intestine (n = 30) and treated by intraperitoneal administration of IgG (n = 15) or the TGF-beta(1) neutralizing antibody (n = 15). Treatment with the antibody against TGF-beta(1) resulted in more definite mucosal growth and increased vascularity on day 5 after surgery. Augmented mRNA expression of epidermal growth factor and vascular endothelial growth factor, and an increased number of cells that expressed these peptides in granulation tissue were demonstrated by RT-PCR and immunohistochemical staining. Taken together it was indicated that TGF-beta(1) has negative effects on regeneration of the bowel wall mucosa and angiogenesis in the course of intestinal anastomotic wound healing.

Propofol depressed neutrophil hydrogen peroxide production more than midazolam, whereas adhesion molecule expression was minimally affected by both anesthetics in rats with abdominal sepsis

The treatment of sepsis may require mechanical ventilation of the lungs and sedation. Because neutrophils are the most important effector cells for protecting against sepsis, and propofol and midazolam are the most widely used anesthetics for sedation, we studied the effects of these two anesthetics on the neutrophil function during sepsis. Sepsis was induced in rats by cecal ligation and puncture. At either 4 h or 24 h after cecal ligation and puncture, blood and peritoneal neutrophils were obtained, incubated with the test anesthetics, and the hydrogen peroxide (H(2)O(2)) production and CD11b/c expression were determined by flow cytometry. In both early (at 4 h) and late (at 24 h) sepsis, propofol and midazolam depressed H(2)O(2) production by blood and peritoneal neutrophils at clinical concentrations. Propofol caused more depression than midazolam (P < 0.005). In both early and late sepsis, the effect of the anesthetics on the up-regulation of the stimulation-induced CD11b/c expression on blood neutrophils was minimal at clinical concentrations. If these results ultimately become clinically relevant, midazolam may be preferable to propofol for sedation during sepsis.

Regulatory mechanisms for transforming growth factor beta as an autocrine inhibitor in human hepatocellular carcinoma: implications for roles of smads in its growth

Transforming growth factor beta (TGF-beta) initiates signaling through heteromeric complexes of transmembrane type I and type II serine/threonine kinase receptors. Activated TGF-beta type I receptor phosphorylates receptor-regulated Smads (2 and 3). Antagonistic Smad 7 forms stable association with the activated TGF-beta type I receptor, blocking phosphorylation of receptor-regulated Smads. On the other hand, elevated serum concentration of TGF-beta along with resistance to its growth-inhibitory effect is commonly observed in human hepatocellular carcinoma (HCC) patients. In this study, we investigated the mechanisms of resistance to tumor-derived TGF-beta in human HCC and hepatoblastoma-derived cell lines, focusing on the roles of receptor-regulated Smads and antagonistic Smad 7. HuH-7 and HepG2 cells showed poor response to TGF-beta-mediated growth inhibition. Because neutralization of TGF-beta in the medium or blockage of signal transduction pathway by inductions of dominant negative Smad 2/3 resulted in a stimulation of cell growth, tumor-derived TGF-beta signal acts on cell growth negatively. However, Smad 7 induced by TGF-beta negatively regulated Smad 2 action and rendered most Smad 2 proteins in the cytoplasm. Taken together, these results indicate that endogenous TGF-beta-mediated induction of Smad 7 results in a higher "threshold" for the antiproliferative signals mediated by receptor-regulated Smads, and can be involved in reduced responsiveness to the cytokine in some human HCC cells.

Transcriptional activation of JC virus by human T-lymphotropic virus type I Tax protein in human neuronal cell lines

Polyomavirus JC (JCV) causes the human demyelinating disease, progressive multifocal leukoencephalopathy (PML). The recent demonstration of cases of PML in association with human T-lymphotropic virus type I (HTLV-I) infection prompted us to examine whether the HTLV-I-encoded regulatory protein Tax activates JCV transcription. By employing a dual luciferase assay, we initially found that the expression of Tax activated the transcriptional potential of both early and late promoters of JCV in human neuronal but not in non-neuronal cells. We subsequently analyzed the mechanism of Tax-induced activation of the JCV promoter in neuronal cells with the following results: 1) the JCV promoter that lacks the NF-kappaB-binding motif could not be activated by Tax; 2) the overexpression of IkappaBalpha abolished Tax-induced transcriptional activation of the JCV promoter; 3) a Tax mutant (M22) lacking the potential for activation via the NF-kappaB pathway did not activate the JCV promoter. Furthermore, Tax enhances the gene expression of JCV T antigen and VP1. We examined mechanisms of the cell-specific activation of the JCV promoter by Tax. Electrophoretic mobility shift assay demonstrated the presence of Tax-bound protein(s) that were specifically present in non-neuronal cells. This study is the first demonstration of the activation of JCV promoter by HTLV-I Tax in an NF-kappaB-dependent manner.

Morphologic differentiation of HL-60 cells is associated with appearance of RPTPbeta and induction of Helicobacter pylori VacA sensitivity

Phorbol 12-myristate 13-acetate (PMA) induces differentiation of human leukemic HL-60 cells into cells with macrophage-like characteristics and enhances the susceptibility of HL-60 cells to the Helicobacter pylori VacA toxin (de Bernard, M., Moschioni., M., Papini, E., Telford, J. L., Rappuoli, R., and Montecucco, C. (1998) FEBS Lett. 436, 218-222). We examined the mechanism by which HL-60 cells acquire sensitivity to VacA, in particular, looking for expression of RPTPbeta, a VacA-binding protein postulated to be the VacA receptor (Yahiro, K., Niidome, T., Kimura, M., Hatakeyama, T., Aoyagi, H., Kurazono, H., Imagawa, K., Wada, A., Moss, J., and Hirayama, T. (1999) J. Biol. Chem. 274, 36693-36699). PMA induced expression of RPTPbeta mRNA and protein as determined by RNase protection assay and indirect immunofluorescence studies, respectively. Vitamin D(3) and interferon-gamma, which stimulate differentiation of HL-60 cells into monocyte-like cells, also induced VacA sensitivity and expression of RPTPbeta mRNA, whereas 1. 2% Me(2)SO and retinoic acid, which stimulated the maturation of HL-60 into granulocyte-like cells, did not. RPTPbeta antisense oligonucleotide inhibited induction of VacA sensitivity and expression of RPTPbeta. Double immunostaining studies also indicated that newly expressed RPTPbeta colocalized with VacA in PMA-treated HL-60 cells. In agreement with these data, BHK-21 cells, which are insensitive to VacA, when transfected with the RPTPbeta cDNA, acquired VacA sensitivity. All data are consistent with the conclusion that acquisition of VacA sensitivity by PMA-treated HL-60 cells results from induction of RPTPbeta, a protein that functions as the VacA receptor.

Autocrine stimulatory mechanism by transforming growth factor beta in human hepatocellular carcinoma

The serum concentration of transforming growth factor beta (TGF-beta) is elevated as tumors progress in hepatocellular carcinoma (HCC) patients. In this study, we examined whether modulation of tumor-derived TGF-beta signal transduction contributes to malignant progression. We investigated the production of TGF-beta1, the biological effects of TGF-beta and neutralizing antibody on HCC cells, activation of Smad 2, Smad 3, and Smad 4, induction of antagonistic Smads (Smad 6 and Smad 7), and promoter activities of two target genes, plasminogen activator inhibitor type 1 (PAI-1) and p15INK4B. In human cell lines HCC-M and HCC-T, TGF-beta accelerates their proliferation. Smad 2 was activated constitutively by an autocrine mechanism, because in the absence of exogenous TGF-beta, a high level of Smad 2 phosphorylation, induction of PAI-1 transcripts, and nuclear localization of Smad 2 were observed. This constitutive activation of Smad 2 was, at least in part, attributable to the lack of induction of antagonistic Smads by TGF-beta. However, Smads activated by tumor-derived TGF-beta constantly suppressed p151NK4B expression. In addition, 3 of 10 human HCC tissues showed nuclear localization of Smad 2 and low mRNA levels of p15INK4B and antagonistic Smads but a high level of PAI-1. Our observations suggest that this constant suppression of the p15INK4B gene could be involved in the malignant progression of HCC.

Involvement of the p38 mitogen-activated protein kinase pathway in transforming growth factor-beta-induced gene expression

Transforming growth factor-beta (TGF-beta)-activated kinase 1 (TAK1), a member of the mitogen-activated protein kinase kinase kinase family, is suggested to be involved in TGF-beta-induced gene expression, but the signaling mechanism from TAK1 to the nucleus remains largely undefined. We have found that p38 mitogen-activated protein kinase, and its direct activator MKK6 are rapidly activated in response to TGF-beta. Expression of dominant negative MKK6 or dominant negative TAK1 inhibited the TGF-beta-induced transcriptional activation as well as the p38 activation. Constitutive activation of the p38 pathway in the absence of TGF-beta induced the transcriptional activation, which was enhanced synergistically by coexpression of Smad2 and Smad4 and was inhibited by expression of the C-terminal truncated, dominant negative Smad4. Furthermore, we have found that activating transcription factor-2 (ATF-2), which is known as a nuclear target of p38, becomes phosphorylated in the N-terminal activation domain in response to TGF-beta, that ATF-2 forms a complex with Smad4, and that the complex formation is enhanced by TGF-beta. In addition, expression of a nonphosphorylatable form of ATF-2 inhibited the TGF-beta-induced transcriptional activation. These results show that the p38 pathway is activated by TGF-beta and is involved in the TGF-beta-induced transcriptional activation by regulating the Smad-mediated pathway.

[Incidence rate of acute myocardial infarction in Hokkaido, Japan]

A survey of acute myocardial infarctions (AMI) that occurred from October 1990 through September 1993 in Obihiro City, Hokkaido, was conducted. A total of 114 new cases of AMI was registered over the 3-year period. The incidence rate of AMI was 33.4 cases per 100,000 men per year and 137 cases per 100,000 women per year (total, 23.2 cases). The mean age at which AMI occurred was 11 years higher in women (71.1 +/- 9.4 years) than in men (60.0 +/- 11.8 years). In men, AMI was most common during the eighth decade of life, while in women the incidence of AMI increased after menopause. The ratio of cases of AMI to cases of stroke in the same period was 1:4.5. These results did not differ from the results of other surveys done over the same period in seven other area of Japan. To study risk factors for myocardial infarction, the data were grouped according to the results of medical examinations. Hypertension, diabetes, obesity and smoking were common among people with AMI. The incidence rate of hypercholesterolemia did not differ between those with AMI and those without, and only a relatively small number of people with AMI drank alcohol. Past reports have pointed out changes in the 'structure' of cardiovascular disease in Japan, which have accompanied changes in diet and lifestyle. This study has shows that aging hypertension, diabetes, obesity, and smoking are risk factors for myocardial infarction. Proper management, including early detection of these factors, will help to prevent of ischemic heart disease in Japan.

[Prevalence of glucose intolerance in Japan--from the National Circulatory Disorders Basic Survey, 1990]

The prevalence of glucose intolerance was surveyed in 8,063 people over 30 years old from the general population of Japan. The data used in the analysis were from the Fourth National Circulatory Disorders Basic Survey, which was conducted in 1990. Survey items included history of diabetes mellitus, body mass index (BMI) and daily life activity. Blood and urine were also examined, and the blood glucose levels, presence or absence of sugar in urine, and levels of glycohemoglobin (HbA1c) were determined. Glucose intolerance was identified from the blood glucose level, HbA1c level and history of diabetes mellitus. The frequency of glucose intolerance was 8.6% in all subjects (11.9% in men and 6.3% in women). The frequency was higher in older people: 1.7 times higher in men over 65 years old and 2.5 times higher in women over 65 years old. Among people over 40 years old, glucose intolerance was significantly more prevalent in men than in women. It was also significantly more prevalent in men living in big cities than in men living in rural areas. Among obese male subjects and men with a low level of activity in daily life, the frequency of glucose intolerance was higher than in normal male subjects. The level of activity in daily life tended to be lower for people living in big cities than for those in rural areas. The results suggest that the prevalence of glucose intolerance depends on the environment in which people live. The results also indicate that raising the level of activities in daily life might help prevent diabetes mellitus.

Histiocytoid breast carcinoma: histological, immunohistochemical, ultrastructural, cytological and clinicopathological studies

Histiocytoid breast carcinoma (HBC) is a rare variant of breast carcinoma and often causes a diagnostic dilemma because of its histological similarities to some types of breast cancer and benign lesions. To elucidate the incidence of HBC and its biological properties, histological specimens from 1010 breast cancer patients treated at Yokohama Minami Kyosai Hospital between 1972 and 1996 were reviewed. Three cases of pure HBC and three cases of combined HBC (two with pleomorphic lobular carcinoma and one with apocrine ductal carcinoma) were found, yielding an incidence of 0.3% for each. Two of the three pure HBC cases contained foci of in situ lobular carcinoma. Targetoid and Indian file invasive patterns, the features characteristic of lobular carcinoma, were present in all three pure HBC cases and in two of the three combined HBC with pleomorphic lobular carcinoma. These results, together with those of previous studies, suggested that the majority of HBC are of lobular origin, although the apocrine ductal origin is also possible in a small number of HBC. Diastase-resistant periodic acid-Schiff-positive granules and granular immunoreactivities for gross cystic disease fluid protein-15 (GCDFP-15) were characteristic of the histiocytoid tumor cells in both the pure and combined HBC, suggesting the apocrine differentiation of tumor cells. All three pure HBC cases were in stage 1 and were free of the disease for up to 5 years and 1 month after the lumpectomy. Thus, the prognosis of HBC appears to be dependent on the stage of the disease and may not always be poor, as indicated by the original report mentioning a preferential eyelid metastasis.

Identification of ligand recognition sites in heat-stable enterotoxin receptor, membrane-associated guanylyl cyclase C by site-directed mutational analysis

Guanylyl cyclase C (STaR), a receptor protein for heat-stable enterotoxin (STa) elaborated by Escherichia coli, is associated with and spans the plasma membrane of mammalian intestinal cells. The extracellular domain functions in the binding of STa and the association of each domain to an oligomeric form. Two amino acid residues, Arg-136 and Asp-347, were identified as the residues binding to STa in the extracellular domain of pig STaR by site-directed mutagenesis and analysis of expression on 293T cells. Replacement of these residues by other amino acid residues resulted in the loss of binding of pig STaR to STa, and as a result, STa-induced guanylyl cyclase activity was eliminated. Furthermore, mutation in a region (from Asp-347 to Val-401) which is close to the transmembrane domain caused a significant reduction in both STa-binding activity and guanylyl cyclase catalytic activity. These results suggest that the region adjacent to the transmembrane domain plays an important role in facilitating a favorable conformation of STaR for STa binding.

Uncleaved env gp160 of human immunodeficiency virus type 1 is degraded within the Golgi apparatus but not lysosomes in COS-1 cells

The fate of newly synthesized human immunodeficiency virus type 1 env gp160 was examined in COS-1 cells. The results of morphological chase experiments involving cycloheximide demonstrated that gp160 was retained in the Golgi apparatus for longer than the half-life of the molecule. The degradation of gp160 was insensitive to both bafilomycin A1 and leupeptin (< 0.2 mM), which block lysosomal proteolysis. However, degradation was effectively suppressed by leupeptin at higher concentrations, maximally at 1.7 mM. Furthermore, undegraded gp160 was accumulated in the Golgi apparatus, but was not detected in lysosomes. These results indicate that in COS-1 cells gp160 is not degraded in lysosomes, but rather that degradation takes place in the Golgi apparatus.

[Randomized controlled study on adjuvant immunochemotherapy with carmofur (HCFU) for noncuratively resected and unresected gastric cancer]

To evaluate the efficacy of adjuvant immunochemotherapy, especially the long-term administration of HCFU to patients with noncuratively resected and unresected gastric cancer, a randomized controlled study was conducted by 16 institutions in Hokkaido. After surgery, 185 patients were divided into two groups using the envelope method; group A (84 patients) treated by MMC (4 mg, twice a week, total 1 mg/kg)+OK-432 (or PSK): group B (101 patients) treated with MMC+OK-432+HCFU (600 mg, per day). The 5- and 10-year survival rates were 9.8 and 3.1% in group A, and 11.1 and 11.1% in group B (p=0.062). Better survival rates were obtained in those cases with unresected, S3, or peritoneal dissemination in group B. These results suggested the long-term administration of HCFU was effective for noncuratively resected and unresected gastric cancer.

HTLV-1 Tax enhances NF-kappa B2 expression and binds to the products p52 and p100, but does not suppress the inhibitory function of p100

Tax protein of HTLV-1 triggers transcriptional activation through enhancers, NF-kappa B binding site, 21-bp enhancer, and serum response element. Previously, we demonstrated binding of Tax to transcription factors NF-kappa B1 p105 and p50. Here, we report that Tax enhances expression of NF-kappa B2 at the mRNA level and proteins; the effect was more apparent on the p52 expression than on its precursor p100, suggesting post-translational regulation. Consistent with these observations, HTLV-1-infected T-cell lines expressed higher levels of p52. Tax binds to the protein products p52 and p100 which inhibits NF-kappa B proteins forming cytoplasmic complexes; the binding to p100 was preferential over NF-kappa B1 p105. However, Tax did not induce efficient dissociation of the cytoplasmic complexes p100/c-Rel or p100/p65, and thus did not induce nuclear translocation of c-Rel or p65. This was in sharp contrast to the previous observation that Tax dissociated the p105/c-Rel and I kappa B-gamma/p65 complexes. These results indicate that HTLV-1 Tax interacts with NF-kappa B2 p100 and p52 and upregulate the NF-kappa B function, but their contribution to Tax-mediated transcriptional regulation differs from those of NF-kappa B1.

Identification of transcriptional activation domain of TREB5, a CREB/ATF family protein that binds to HTLV-1 enhancer

TREB5 (hXBP-1) protein is a transcription factor that recognizes the CRE-like element in enhancers of human T-cell leukemia virus and MHC class II gene and activates their transcription. TREB5 is a member of the CREB/ATF family, containing a basic amino acid region and leucine zipper structure (b-Zip structure). To characterize the key domain of TREB5 for transcriptional activation, mutational analysis was carried out. The C-terminal region of 148-221 amino acids was identified as an activation domain and was also active when fused to Gal4 DNA binding domain. This domain contains three unique regions rich in glutamic acid, glutamine, or serine/threonine and is active in both osteosarcoma (HOS) and T (Jurkat) cell lines. All of these three regions are essential; however, a part of the serine/threonine region was dispensable in Jurkat, but not in HOS cells. In addition to the activation domain, the N-terminal region showed activity in conjunction with the b-Zip structure, but not with the Gal4 DNA binding domain. Furthermore, this region showed activity in Jurkat cells, but not in HOS cells. These results suggest that TREB5 has two activational functions in transcription and may provide diversity in cell-type-specific transcriptional activation, possibly through dimerization with other b-Zip proteins and phosphorylation.

[Effect of continuous infusion of 5-fluorouracil and daily low-dose cisplatin for inoperable recurrent cancer of the stomach and colon]

With the use of cisplatin to enhance the effect of 5-FU, a combined approach was designed to treat patients with inoperable recurrent cancer of the stomach (15) and colon (6). This CDDP-5-FU therapy consisted of intermittent infusion of CDDP at a dose of 6 mg/m2 every day and continuous infusion of 5-FU at a daily dose of 200 mg/m2 for 2 weeks with a 2-week interval in between. There were 1CR and 6PR, and the overall response rate was 40.0%. Toxicity was manifested in slight nausea or vomiting in two patients (10.0%), but there was no nephrotoxity. Thrombocytopenia of Grade 4 was found in 1 patient and leucopenia of Grade 3 in another. The efficiency of performance status was in 14 patients (66.7%). Combination of daily low-dose cisplatin and 5-FU is a tolerable treatment for patients with inoperable recurrent stomach and colon cancer. It is suggested that CDDP plays a role as not only an effector but also a modulator in biochemical modulation of 5-FU in this therapy. The infusion schedule is also suitable for chemotherapy of outpatients. Further studies on the appropriate infusion of CDDP and 5-FU are needed.

[A case of metastatic breast cancer successfully treated with weekly low-dose epirubicin (EPI), cyclophosphamide (CPA), 5-fluorouracil (5-FU) and medroxyprogesterone (MPA)]

We reported a case of successful treatment of disseminated breast cancer with epirubicin (EPI), 5-fluorouracil (5-FU), and medroxyprogesterone (MPA). The patient was a 49-year-old female with bone and liver metastasis developed 5 years after surgery. The primary tumor was ER-positive, and she had been treated previously with adjuvant therapy using UFT and tamoxifen. The treatment consisted of 3 cycles of thrice-weekly EPI (40mg), 5-FU (500mg) and CPA (500mg). The patient was then treated with a weekly schedule of EPI (10mg), 5-FU (50mg/day), CPA (50mg/day) and MPA (400mg/day). After 2 years, her bone and liver metastasis showed remarkable remission (PR). No side effects of this chemotherapy were observed. In the search for palliative treatments which have a minimal impact on normal lifestyle, low toxicity is important. PR was continued for 2 years, and the patient enjoyed a favorable quality of life. This low dose-weekly approach was very well tolerated, yet was effective.

Pig intestinal membrane-bound receptor (guanylyl cyclase) for heat-stable enterotoxin: cDNA cloning, functional expression, and characterization

A cDNA encoding the receptor protein for a heat-stable enterotoxin (STa) produced by enterotoxigenic Escherichia coli was cloned from intestinal epithelial cells of a 10-week-old pig. The cDNA had an open reading frame of 3,219 base pairs and coded for a protein with 1,073 amino acid residues. The mature protein consisted of 1,050 amino acid residues with a molecular mass of ca. 121 kDa and was 87% and 82% identical with the human and rat protein, respectively. The CHO cell line overexpressing the pig recombinant STa receptor specifically bound to a photoaffinity-labeled analog of STa and showed marked elevation of the cellular content of cGMP in response to STa.